,transcriber's ,notes3 ,underscores 80 before and after a word or phrase indicate italics in the original text4 ,equal signs 80 before and after a word or phrase indicate bold in the original text4 ,a single underscore after a symbol indicates a subscript4 ,small capitals have been converted to ,,solid capitals4 ,illustrations have been moved so they do not break up paragraphs4 ,antiquated spellings have been preserved4 ,typographical and punctuation errors have been silently corrected4 ,the 8,,corrections ,,for ,,vol4 ,,iii40 listed at the end of the book have already been applied to the text by the transcriber4 ,,principles ,,and ,,practice ,,of ,,agricultural ,,analysis4 ,a ,,manual ,,for ,,the ,,examination ,,of ,,soils1 ,,fertilizers1 ,,and ,,agricultural ,,products4 ,,for ,,the ,,use ,,of ,,analysts1 ,,teachers1 ,,and ,,students ,,of ,,agricultural ,,chemistry4 ,,volume ,,iii4 ,,agricultural ,,products4 ,,by ,,harvey ,w4 ,,wiley1 ,,chemist ,,of ,,the ,u4 ,s4 ,,department ,,of ,,agriculture4 ,,easton1 ,,pa4 ,,chemical ,,publishing ,,co4 #ahig4 ,,copyright1 #ahig1 ,,by ,,harvey ,w4 ,,wiley4 ,,preface ,,to ,,volume ,,third4 ,the concluding volume of the ,principles and ,practice of ,agricultural ,analysis has been written in harmony with the plan adopted at the commencement of the first volume4 ,in it an effort has been made to place the analyst or student en rapport with all the best methods of studying the composition of agricultural products4 ,during the progress of the work the author has frequently been asked why some special method in each case has not been designated as the proper one to be used4 ,to do this would be a radical departure from the fundamental idea of the work2 viz41 to rely on the good judgment and experience of the chemist4 ,it is not likely that the author's judgment in such matters is better than that of the analyst using the book1 and1 except for beginning students pursuing a course of laboratory instruction1 a biased judgment is little better than none at all4 ,for student's work in the laboratory or classroom it is probable that a volume of selected methods based on the present work may be prepared later on1 but this possible future need has not been allowed to change the purpose of the author as expressed in the preface of the second volume 8to present to the busy worker a broad view of a great subject40 ,for the courtesy and patience of the publishers1 for the uniformly commendatory notices of the reviewers of volumes one and two1 and for the personal encouraging expressions of his professional brethren the author is sincerely grateful4 ,he finds in this cordial reception of his book a grateful compensation for long years of labor4 ,the plates of the first edition of the three volumes have been destroyed in order to insure a re-writing of the second edition when it shall be demanded1 in order to keep it abreast of the rapid progress in the field of agricultural chemical analysis4 ,,washington1 ,d4 ,c41 ,beginning of ,january1 #ahig4 ,,table ,,of ,,contents ,,of ,,volume ,,third4 ,,part ,,first4 ,,sampling1 ,,drying1 ,,incineration ,,and ,,extractions4 ,introduction1 pp4 #a-c4--,methods of study2 ,scope of the work2 ,limitations of work2 ,general manipulations4 ,methods of ,sampling1 pp4 #c-ac4--,vegetable substances2 ,animal substances2 ,preserving samples2 ,collecting samples2 ,grinding samples2 ,grinding apparatus4 ,drying ,organic ,bodies1 pp4 #ac-cf4--,volatile bodies2 ,drying ovens2 ,air baths2 ,drying in vacuum2 ,electric drying ovens2 ,steam coil apparatus2 ,drying in hydrogen2 ,drying in tubes2 ,drying viscous liquids2 ,general principles of drying4 ,incineration1 pp4 #cf-dj4--,principles of incineration2 ,products of combustion2 ,purpose and conduct of incineration2 ,german ash method2 ,courtonne's muffle4 ,extraction of ,organic ,bodies1 pp4 #dj-eg4--,object of extraction2 ,solvents2 ,methods of extraction2 ,extraction by digestion2 ,extraction by percolation2 ,apparatus for extraction2 ,knorr's extraction apparatus2 ,soxhlet's extraction apparatus2 ,compact extraction apparatus2 ,recovery of solvents2 ,authorities cited in ,part ,first4 ,,part ,,second4 ,,sugars ,,and ,,starches4 ,introduction1 pp4 #eh-fb4--;,carbohydrates2 ,nomenclature2 ,preparation of pure sugar2 ,classification of methods of analysis4 ,analysis by ,density of ,solution1 pp4 #fc-gb4--,principles of the method2 ,pyknometers2 ,calculating volume of pyknometers2 ,hydrostatic balance2 ,areometric method2 ,correction for temperature2 ,brix hydrometer2 ,comparison of brix and baum degrees2 ,errors due to impurities4 ,estimation of ,sugars with ,polarized ,light1 pp4 #gd-abj4--,optical properties of sugars2 ,polarized light2 ,nicol prism2 ,polariscope2 ,kinds of polariscopes2 ,character of light2 ,description of polarizing instruments3 ,laurent polariscope2 ,polariscope lamps2 ,soleil-,ventzke polariscope2 ,half ,shadow polariscope2 ,triple field polariscope2 ,setting the polariscope2 ,control observation tube2 ,quartz plates2 ,correcting quartz plates2 ,application of quartz plates2 ,sugar flasks2 ,preparing sugar solutions for polarization2 ,alumina cream2 ,errors due to lead solutions2 ,double polarization2 ,mercuric compounds2 ,bone-black2 ,inversion of sugar2 ,clerget's method2 ,influence of strength of solution2 ,calculation of results2 ,method of ,lindet2 ,use of invertase2 ,activity of invertase2 ,inversion by yeast2 ,determination of sucrose2 ,determination of raffinose2 ,specific rotatory power2 ,calculating specific rotatory power2 ,variations in specific rotatory power2 ,gyrodynatic data2 ,birotation4 ,chemical ,methods of ,estimating ,sugar1 pp4 #abj-adi4--;,general principles2 ,classification of methods2 ,reduction of mercuric salts2 ,sachsse's solution2 ,volumetric copper methods2 ,action of copper solution on dextrose2 ,fehling's solution2 ,list of copper solutions2 ,volumetric laboratory method2 ,filtering tubes2 ,correction of errors2 ,permanganate process2 ,modified permanganate method2 ,specific gravity of cuprous oxid2 ,soldaini's process2 ,relation of reducing sugar to quantity of suboxid2 ,factors for different sugars2 ,pavy's process2 ,peska's process2 ,method of ,allein and ,gaud2 ,method of ,gerrard2 ,sidersky's modification2 ,titration of excess of copper4 ,gravimetric ,copper ,methods1 pp4 #adi-agj4--;,general principles2 ,laboratory copper method2 ,halle method2 ,allihn's method2 ,meissl's method2 ,determination of invert sugar2 ,estimation of milk sugar2 ,determination of maltose2 ,preparation of levulose2 ,estimation of levulose4 ,miscellaneous ,methods of ,sugar ,analysis1 pp4 #aga-aif2 ,phenylhydrazin2 ,molecular weights of carbohydrates2 ,birotation2 ,estimation of pentosans2 ,determination of furfurol2 ,method of ,tollens2 ,method of ,stone2 ,method of ,chalmot2 ,method of ,krug2 ,precipitation with pyrogalol2 ,precipitation with phloroglucin2 ,fermentation methods2 ,estimating alcohol2 ,estimating carbon dioxid2 ,precipitation with earthy bases2 ,barium saccharate2 ,strontium saccharate2 ,calcium saccharate2 ,qualitive tests2 ,optical tests2 ,cobaltous nitrate test2 ,the ,dextrose group2 ,tests for levulose2 ,tests for galactose2 ,tests for invert sugar2 ,compounds with phenylhydrazin2 ,detection of sugars by means of furfurol2 ,bacterial action on sugars4 ,determination of ,starch1 pp4 #aif-bbf4--;,constitution of starch2 ,separation of starch2 ,methods of separation2 ,separation with diastase2 ,separation in an autoclave2 ,principles of analysis2 ,estimation of water2 ,estimation of ash2 ,estimation of nitrogen2 ,hydrolysis with acids2 ,factors for calculation2 ,polarization of starch2 ,solution at high pressure2 ,method of ,hibbard2 ,precipitation with barium hydroxid2 ,disturbing bodies in starch determinations2 ,colorimetric estimation of starch2 ,fixation of iodin2 ,identification of starches2 ,vogel's table2 ,muter's table2 ,blyth's classification2 ,preparation of starches for the microscope2 ,mounting in canada balsam2 ,description of typical starches2 ,authorities cited in ,part ,second4 ,,part ,,third4 ,,separation ,,and ,,determination ,,of ,,carbohydrates ,,in ,,crude ,,or ,,manufactured ,,agricultural ,,products4 ,sugars in ,vegetable ,juices1 pp4 #bbg-bec4--;,introduction2 ,sugar in the sap of trees2 ,sugar in sugar canes2 ,weighing pipettes2 ,gravimeter2 ,reducing sugars in juices2 ,preservation of juices2 ,direct estimation of sugar2 ,cutting or shredding canes2 ,methods of analysis2 ,drying and extracting2 ,examination of bagasse2 ,fiber in canes2 ,sugar beets2 ,estimation of sugar in sugar beets2 ,machines for pulping beets2 ,instantaneous diffusion2 ,pellet's process2 ,alcohol digestion2 ,extraction with alcohol2 ,determination of sugar in mother beets2 ,determination of sugars without weighing2 ,continuous observation tube4 ,analysis of ,sirups and ,massecuites1 pp4 #bed-bfd4--,specific gravity2 ,determination of water2 ,determination of ash2 ,determination of reducing sugars2 ,estimation of minute quantities of invert sugar2 ,soldaini's gravimetric method2 ,weighing the copper as oxid2 ,analyses for factory control4 ,separation of ,carbohydrates in ,mixtures1 pp4 #bfd-bib4--,occurrence of sugars2 ,optical methods2 ,optical neutrality of invert sugar2 ,separation of sucrose and invert sugar2 ,separation of sucrose and raffinose2 ,determination of levulose2 ,formula for calculating levulose2 ,separation of sucrose from dextrose2 ,estimation of lactose in milk2 ,error due to volume of precipitate2 ,separation of sucrose1 levulose and dextrose2 ,sieben's method2 ,wiechmann's method2 ,copper carbonate method2 ,winter's process2 ,separation with lead oxid2 ,analysis of commercial glucose and grape sugar2 ,fermentation method2 ,oxidation method2 ,removal of dextrose by copper acetate2 ,separation of dextrin with alcohol4 ,carbohydrates in ,milk1 pp4 #bic-bih4--;,copper tartrate method2 ,the official method2 ,the copper cyanid process2 ,separation of sugars in evaporated milks2 ,method of ,bigelow and ,mc,elroy4 ,separation and ,determination of ,starch and ,fiber1 pp4 #bih-cjf4--,occurrence2 ,separation of starch2 ,dry amyliferous bodies2 ,indirect method of determining water2 ,removal of oils and sugars2 ,preparation of diastase2 ,estimation of starch in potatoes2 ,constitution of cellulose2 ,fiber in cellulose2 ,official method2 ,separation of cellulose3 ,solubility of cellulose2 ,qualitive reactions for cellulose2 ,rare carbohydrates2 ,authorities cited in ,part ,third4 ,,part ,,fourth4 ,,fats ,,and ,,oils4 ,general ,principles1 pp4 #cji-caf4--,nomenclature2 ,composition2 ,principal glycerids2 ,presses for extraction2 ,solvents2 ,freeing extracts of petroleum2 ,freeing fats of moisture2 ,sampling and drying for analysis2 ,estimation of water4 ,physical ,properties of ,fats and ,oils1 pp4 #cag-cej4--,specific gravity2 ,balance for determining specific gravity2 ,expression of specific gravity2 ,coefficient of expansion of oils2 ,densities of common fats and oils2 ,melting point2 ,determination in capillary tube2 ,determination by spheroidal state2 ,solidifying point2 ,temperature of crystallization2 ,refractive power2 ,refractive index2 ,abbe's refractometer2 ,pulfrich's refractometer2 ,refractive indices of common oils2 ,oleorefractometer2 ,butyrorefractometer2 ,range of application of the butyrorefractometer2 ,viscosity2 ,torsion viscosimeter2 ,microscopic appearance2 ,preparation of fat crystals2 ,observation of fat crystals with polarized light2 ,spectroscopic examination of oils2 ,critical temperature2 ,polarization2 ,turbidity temperature4 ,chemical ,properties of ,fats and ,oils1 pp4 #cea-djf4--,solubility in alcohol2 ,coloration produced by oxidants2 ,nitric acid coloration2 ,phosphomolybdic acid coloration2 ,picric acid coloration2 ,silver nitrate coloration2 ,stannic bromid coloration2 ,auric chlorid coloration2 ,thermal reactions2 ,heat of sulfuric saponification2 ,maumen's process2 ,method of ,richmond2 ,relative maumen figure2 ,heat of bromination2 ,method of ,hehner and ,mitchell2 ,author's method2 ,haloid addition numbers2 ,hbl number2 ,character of chemical reaction2 ,solution in carbon tetrachlorid2 ,estimation of the iodin number2 ,use of iodin monochlorid2 ,preservation of the hbl reagent2 ,bromin addition number2 ,method of ,hehner2 ,halogen absorption by fat acids2 ,saponification2 ,saponification in an open dish2 ,saponification under pressure2 ,saponification in the cold2 ,saponification value2 ,saponification equivalent2 ,acetyl value2 ,determination of volatile fat acids2 ,removal of the alcohol2 ,determination of soluble and insoluble fat acids2 ,formulas for calculation2 ,determination of free fat acids2 ,identification of oils and fats2 ,nature of fat acids2 ,separation of glycerids2 ,separation with lime2 ,separation with lead salts2 ,separation of arachidic acid2 ,detection of peanut oil2 ,bechi's test2 ,milliau's test2 ,detection of sesam oil2 ,sulfur chlorid reaction2 ,detection of cholesterin and phytosterin2 ,absorption of oxygen2 ,elaidin reactions2 ,authorities cited in ,part ,fourth4 ,,part ,,fifth4 ,,separation ,,and ,,estimation ,,of ,,bodies ,,containing ,,nitrogen4 ,introduction and ,definitions1 pp4 #daj-dah4--,nature of nitrogenous bodies2 ,classification of proteids2 ,albuminoids2 ,other forms of nitrogen2 ,occurrence of nitrates4 ,qualitive ,tests for ,nitrogenous ,bodies1 pp4 #dah-dbb4--,nitric acid2 ,amid nitrogen2 ,ammoniacal nitrogen2 ,proteid nitrogen2 ,qualitive tests for albumni2 ,qualitive tests for peptones and albuminates2 ,action of polarized light on albumins2 ,alkaloidal nitrogen4 ,estimation of ,nitrogenous ,bodies in ,agricultural ,products1 pp4 #dbc-dcb4--,total nitrogen2 ,ammoniacal nitrogen2 ,amid nitrogen2 ,sachsse's method2 ,preparation of asparagin2 ,estimation of asparagin and glutamin2 ,cholin and betain2 ,lecithin2 ,factors for calculating results2 ,estimation of alkaloidal nitrogen4 ,separation of ,proteid ,bodies in ,vegetable ,products1 pp4 #dcb-ddh4--,preliminary treatment2 ,character of proteids2 ,separation of gluten2 ,extraction with water2 ,action of water on composition of proteids2 ,extraction with dilute salt solution2 ,separation of bodies soluble in water2 ,separation of the globulins2 ,proteids soluble in dilute alcohol2 ,solvent action of acids and alkalies2 ,method of extraction2 ,methods of drying separated proteids2 ,determination of ash2 ,determination of carbon and hydrogen2 ,estimation of nitrogen2 ,determination of sulfur2 ,dialysis4 ,separation and ,estimation of ,nitrogenous ,bodies in ,animal ,products1 pp4 #ddh-dfb4--,preparation of sample2 ,extraction of muscular tissues2 ,composition of meat extracts2 ,analysis of meat extracts2 ,use of phosphotungstic acid2 ,separation of albumoses and peptones2 ,estimation of gelatin2 ,estimation of nitrogen in flesh bases2 ,treatment of residue insoluble in alcohol2 ,pancreas peptone2 ,albumose peptone2 ,authorities cited in ,part ,fifth4 ,,part ,,sixth4 ,,dairy ,,products4 ,milk1 pp4 #dfd-eab4--;,composition of milk2 ,alterability of milk2 ,effects of boiling on milk2 ,micro-organisms of milk2 ,sampling milk2 ,scovell's milk sampler2 ,preserving milk for analysis2 ,freezing point2 ,electric conductivity2 ,viscosity2 ,acidity and alkalinity2 ,determination of acidity2 ,opacity2 ,creamometry2 ,specific gravity2 ,lactometry2 ,quvenne lactometer2 ,lactometer of the ,new ,york ,board of ,health2 ,density of sour milk2 ,density of milk serum2 ,total solids2 ,formulas for calculating total solids2 ,determination of ash2 ,estimation of fat2 ,fat globules2 ,number of fat globules2 ,counting globules2 ,classification of methods of analysis2 ,dry extraction methods2 ,official methods2 ,variations of extraction methods2 ,gypsum method2 ,estimation of fat in malted milk2 ,comparison of fat methods2 ,wet extraction methods2 ,solution in acid2 ,solution in alkali2 ,method of ,short2 ,method of ,thrner2 ,liebermann's method2 ,densimetric methods2 ,areometric methods2 ,lactobutyrometer2 ,volumetric methods of fat analysis2 ,method of ,patrick2 ,the lactocrite2 ,modification of ,lindstrm2 ,babcock's method2 ,method of ,leffmann and ,beam2 ,method of ,gerber2 ,proteid bodies in milk2 ,estimation of total proteid matter2 ,copper sulfate as a reagent2 ,precipitation by ammonium sulfate2 ,precipitation by tannic acid2 ,separation of casein from albumin2 ,estimation of casein2 ,factors for calculation2 ,separation of casein2 ,separation of casein with carbon dioxid2 ,separation of albumin2 ,separation of globulin2 ,precipitants of milk proteids2 ,precipitation by dialysis2 ,carbohydrates in milk2 ,dextrinoid body in milk2 ,amyloid bodies in milk4 ,butter1 pp4 #eab-ebc4--;,general principles of analysis2 ,appearance of melted butter2 ,microscopic examination2 ,refractive power2 ,estimation of water1 fat1 casein1 ash and salt2 ,volatile and soluble acids2 ,relative proportion of glycerids2 ,saponification value2 ,reichert number2 ,reichert-,meissl method2 ,elimination of sulfurous acid2 ,errors due to poor glass2 ,molecular weight of butter2 ,substitutes for and adulterants of butter2 ,butter colors4 ,cheese and ,koumiss1 pp4 #ebd-ecf4--;,composition of cheese2 ,manufacture of cheese2 ,official methods of analysis2 ,process of ,mueller2 ,separation of fat from cheese2 ,filled cheese2 ,separation of nitrogenous bodies2 ,preparation of koumiss2 ,determination of carbon dioxid2 ,acidity2 ,estimation of alcohol2 ,proteids in koumiss2 ,separation by porous porcelain2 ,separation by precipitation with alum2 ,separation with mercury salts2 ,determination of water and ash2 ,composition of koumiss2 ,authorities cited in ,part ,sixth4 ,,part ,,seventh4 ,,miscellaneous ,,agricultural ,,products4 ,cereals and ,cereal ,foods1 pp4 #eda-ede4-- ,classification2 ,general methods of analysis2 ,composition and analysis of bread2 ,determination of alum in bread2 ,chemical changes produced by baking4 ,fodders1 ,grasses1 and ,ensilage1 pp4 #ede-edg4--;,general principles of analysis2 ,organic acids in ensilage2 ,changes due to fermentation2 ,alcohol in ensilage2 ,comparative values of dry fodder and ensilage4 ,flesh ,products1 pp4 #edg-eee4--,names of meats2 ,sampling2 ,general methods of analysis2 ,examination of nitrogenous bodies2 ,fractional analysis of meats2 ,starch in meats2 ,detection of horse flesh4 ,methods of ,digestion1 pp4 #eee-efd4--;,artificial digestion2 ,amylolytic ferments2 ,aliphalytic ferments2 ,proteolytic ferments2 ,pepsin and pancreatin2 ,digestion in pancreas extract2 ,artificial digestion of cheese2 ,natural digestion2 ,digestibility of pentosans4 ,preserved ,meats1 pp4 #efe-eff4--,methods of examination2 ,estimation of fat2 ,meat preservatives4 ,determination of ,nutritive ,values1 pp4 #eff-egf4--,nutritive value of foods2 ,comparative value of food constituents2 ,nutritive ratio2 ,calorimetric analysis of foods2 ,combustion in oxygen2 ,bomb calorimeter2 ,manipulation and calculation2 ,computing the calories of combustion2 ,calorimetric equivalents2 ,distinction between butter and oleomargarin4 ,fruits1 ,melons and ,vegetables1 pp4 #egg-ehb4-- ,preparation of samples2 ,separation of carbohydrates2 ,examination of the fresh matter2 ,examination of fruit and vegetable juices2 ,separation of pectin2 ,determination of free acid2 ,composition of fruits2 ,composition of ash of fruits2 ,dried fruits2 ,zinc in evaporated fruits2 ,composition of melons4 ,tea and ,coffee1 pp4 #ehb-ehh4--,special points in analysis2 ,estimation of caffein2 ,iodin method2 ,spencer's method2 ,separation of chlorophyll2 ,determination of proteid nitrogen2 ,carbohydrates of coffee2 ,estimation of galactan2 ,revised factors for pentosans2 ,use of roentgen rays4 ,tannins and ,allied ,bodies1 pp4 #ehh-eif4-- ,occurrence and composition2 ,detection and estimation2 ,precipitation with metallic salts2 ,the gelatin method2 ,the hide powder method2 ,permanganate gelatin method2 ,permanganate hide powder method2 ,preparation of infusion4 ,tobacco1 pp4 #eif-faj4--;,fermented and unfermented tobacco2 ,acid and basic constituents2 ,composition of ash2 ,composition of tobacco2 ,estimation of water2 ,estimation of nitric acid2 ,estimation of sulfuric and hydrochloric acids2 ,estimation of oxalic1 malic and citric acids2 ,estimation of acetic acid2 ,estimation of pectic acid2 ,estimation of tannic acid2 ,estimation of starch and sugar2 ,estimation of ammonia2 ,estimation of nicotin2 ,polarization method of ,popovici2 ,estimation of amid nitrogen2 ,fractional extraction2 ,burning qualities2 ,artificial smoker4 ,fermented ,beverages1 pp4 #faj-fda4-- ,description2 ,important constituents2 ,specific gravity2 ,determination of alcohol2 ,distilling apparatus2 ,specific gravity of the distillate2 ,hydrostatic plummet2 ,calculating results2 ,table giving percentage of alcohol by weight and volume2 ,determination of percentage of alcohol by means of vapor temperature2 ,improved ebullioscope2 ,indirect determination of extract2 ,determination of total acids2 ,determination in a vacuum2 ,estimation of water2 ,total acidity2 ,volatile acids2 ,tartaric acid2 ,tartaric1 malic and succinic acids2 ,polarizing bodies in fermented beverages2 ,reducing sugars2 ,polarization of wines and beers2 ,application of analytical methods2 ,estimation of carbohydrates2 ,determination of glycerol2 ,coloring matters2 ,determination of ash2 ,determination of potash2 ,sulfurous acid2 ,salicylic acid2 ,detection of gum and dextrin2 ,determination of nitrogen2 ,substitutes for hops2 ,bouquet of fermented and distilled liquors2 ,authorities cited in ,part ,seventh2 ,index4 ,,illustrations ,,to ,,volume ,,third4 ,page4 ,figure #a4 ,mill for grinding dry samples #g 0 #b4 ,comminutor for green samples #i 0 #c4 ,rasp for sugar beets #aj 0 #d4 ,dreef grinding apparatus #aa 0 #e4 ,water jacket drying oven #ad 0 #f4 ,thermostat for ,steam-,bath #ae 0 #g4 ,spencer's drying oven #ag 0 #h4 ,electric vacuum drying oven #ai 0 #i4 ,steam coil drying oven #ba 0 #aj4 ,carr's vacuum drying oven #bb 0 #aj4 7,bis47 vacuum oven open #bc 0 #aa4 ,apparatus for drying in a current of hydrogen #be 0 #ab4 ,caldwell's hydrogen drying apparatus #bg 0 #ac4 ,liebig's ente #bh 0 #ad4 ,drying apparatus used at the ,halle ,station #bi 0 #ae4 ,wrampelmayer's oven #cj 0 #af4 ,ulsch drying oven #ca 0 #ag4 ,courtoune muffle #ci 0 #ah4 ,knorr's extraction apparatus #de 0 #ai4 ,extraction flask #df 0 #bj4 ,extraction tube #df 0 #ba4 ,extraction siphon tube #df 0 #bb4 ,soxhlet extraction apparatus #dh 0 #bc4 ,compact condensing apparatus #di 0 #bd4 ,improved compact extraction apparatus #ea 0 #be4 ,knorr's apparatus for recovering solvents #ed 0 #bf4 ,apparatus for recovering solvents from open dishes #ee 0 #bg4 ,common forms of pyknometers #fc 0 #bh4 ,bath for pyknometers #ff 0 #bi4 ,aereometers1 pyknometers and hydrostatic balance #fh 0 #cj4 ,hydrostatic balance #fi 0 #ca4 ,course of rays of light in a nicol #gg 0 #cb4 ,theory of the nicol #gh 0 #cc4 ,laurent lamp #hc 0 #cd4 ,lamp for producing constant monochromatic flame #he 0 #ce4 ,field of vision of a ,laurent polariscope #hf 0 #cf4 ,laurent polariscope #hh 0 #cg4 ,tint polariscope #hi 0 #ch4 ,double compensating shadow polariscope #ia 0 #ci4 ,triple shadow polariscope #ib 0 #dj4 ,apparatus for producing a triple shadow #ib 0 #da4 ,control observation tube #ie 0 #db4 ,apparatus for the volumetric estimation of reducing sugars #aca 0 #dc4 ,apparatus for the electrolytic deposition of copper #aea 0 #dd4 ,apparatus for filtering copper suboxid #aed 0 #de4 ,apparatus for reducing copper suboxid #aed 0 #df4 ,distilling apparatus for pentoses #agi 0 #dg4 ,autoclave for starch analysis #aii 0 #dg4 7,bis74 ,maercker's hydrolyzing apparatus for starch #bjd 0 #dh4 ,maranta starch #cej 0 #di4 ,potato starch #cej 0 #ej4 ,ginger starch #cej 0 #ea4 ,sago starch #cej 0 #eb4 ,pea starch #cej 0 #ec4 ,bean starch #cej 0 #ed4 ,wheat starch #cej 0 #ee4 ,barley starch #cej to face #bbj 0 #ef4 ,rye starch #cej 0 #eg4 ,oat starch #cej 0 #eh4 ,indian corn starch #cej 0 #ei4 ,rice starch #cej 0 #fj4 ,cassava starch #aej 0 #fa4 ,indian corn starch #aej 0 #fb4 ,laboratory cane mill #bcj 0 #fc4 ,weighing pipette #bca 0 #fd4 ,gird's gravimeter #bcc 0 #fe4 ,machine for cutting canes #bcf 0 #ff4 ,cane cutting mill #bcg 0 #fg4 ,apparatus for pulping beets #bdc 0 #fh4 ,apparatus for cold diffusion #bde 0 #fi4 ,sickel-,soxhlet extractor #bdg 0 #gj4 ,scheibler's extraction tube #bdh 0 #ga4 ,battery for alcoholic digestion #bej 0 #gb4 ,rasp for sampling mother beets #bea 0 #gc4 ,hand press for beet analysis #bea 0 #gd4 ,perforating rasp #beb 0 #ge4 ,tube for continuous observation #bec 0 #ge4 7,bis74 ,chandler and ,rickett's ,polariscope #bff 0 #gf4 ,apparatus for polarimetric observations at low temperatures #bfg 0 #gg4 ,construction of desiccating tube #bfh 0 #gh4 ,apparatus for polarizing at high temperatures #bfi 0 #gi4 ,oil press #cab 0 #hj4 ,apparatus for fractional distillation of petroleum ether #cad 0 #ha4 ,section showing construction of a funnel for hot filtration #caf 0 #hb4 ,balance and ,westphal sinker #cah 0 #hc4 ,melting point tubes #cbb 0 #hd4 ,apparatus for the determination of melting point #cbd 0 #he4 ,apparatus for determining crystallizing point #cbg 0 #hf4 ,abbe's refractometer #cbi 0 #hg4 ,charging position of refractometer #ccj 0 #hh4 ,prism of ,pulfrich's refractometer #cca 0 #hi4 ,pulfrich's new refractometer #ccb 0 #ij4 ,heating apparatus for ,pulfrich's refractometer #ccc 0 #ia4 ,spectrometer attachment #ccc 0 #ib4 ,oleorefractometer #cce 0 #ic4 ,section showing construction of oleorefractometer #cce 0 #id4 ,butyrorefractometer #cci 0 #ie4 ,doolittle's viscosimeter #cdc 0 #if4 ,lard crystals #fe 0 #ig4 ,refined lard crystals #fe to face #cdh 0 #ih4 ,apparatus for determining rise of temperature with sulfuric acid #ceh 0 #ii4 ,apparatus for determining heat of bromination #cfb 0 #ajj4 ,olein tube #cgd 0 #aja4 ,apparatus for saponifying under pressure #chj 0 #ajb4 ,apparatus for the distillation of volatile acids #chh 0 #ajc4 ,apparatus for amid nitrogen #dbe 0 #ajd4 ,sachsse's eudiometer #dbe 0 #aje4 ,dialyzing apparatus #ddg 0 #ajf4 ,scovell's milk sampling tube #dgj 0 #ajg4 ,lactoscope1 lactometer1 and creamometer #dgd 0 #ajh4 ,areometric fat apparatus #dic 0 #aji4 ,babcock's butyrometer and acid measure #ejj 0 #aaj4 ,gerber's butyrometers #ejb 0 #aaa4 ,gerber's centrifugal #ejc 0 #aab4 ,thermometer for butyrorefractometer #eae 0 #aac4 ,apparatus for determining carbon dioxid in koumiss #ecc 0 #aad4 ,cuts of mutton #edh 0 #aae4 ,cuts of beef #edh 0 #aaf4 ,cuts of pork #edh 0 #aag4 ,bath for artificial digestion #eei 0 #aah4 ,bag for collecting feces #efc 0 #aai4 ,fecal bag attachment #efc 0 #abj4 ,hempel and ,atwater's calorimeter #egj 0 #aba4 ,apparatus for acetic acid #fjc 0 #abb4 ,apparatus for smoking #faj 0 #abc4 ,metal distilling apparatus #fac 0 #abd4 ,distilling apparatus #fad 0 #abe4 ,improved ebullioscope #fbc ,,volume ,,third4 ,,agricultural ,,products4 ,,part ,,first4 ,,sampling1 ,,drying1 ,,incineration ,,and ,,extractions4 #a4 ,introduction4--,the analyst may approach the examination of agricultural products from various directions4 ,in the first place he may desire to know their proximate and ultimate constitution irrespective of their relations to the soil or to the food of man and beast4 ,secondly1 his study of these products may have reference solely to the determination of the more valuable plant foods which they have extracted from the soil and air4 ,lastly1 he may approach his task from a hygienic or economic standpoint for the purposes of determining the wholesomeness or the nutritive and economic values of the products of the field1 orchard1 or garden4 ,in each case the object of the investigation will have a considerable influence on the method of the examination4 ,it will be the purpose of the present volume to discuss fully the principles of all the standard processes of analysis and the best practice thereof1 to the end that the investigator or analyst1 whatever may be the design of his work1 may find satisfactory directions for prosecuting it4 ,as in the previous volumes1 it should be understood that these pages are written largely for the teacher and the analyst already skilled in the principles of analytical chemistry4 ,much is therefore left to the individual judgment and experience of the worker1 to whom it is hoped a judicious choice of approved processes may be made possible4 #b4 ,scope ,of the ,work4--,under the term agricultural products is included a large number of classes of bodies of most different constitution4 ,in general they are the products of vegetable and animal metabolism4 ,first of all come the vegetable products1 fruits1 grains and grasses4 ,these may be presented in their natural state1 as cereals1 green fruits and fodders1 or after a certain preparation1 as starches1 sugars and flours4 ,they may also be met with in even more advanced stages of change1 as cooked foods1 alcohols and secondary organic acids1 such as vinegar4 ,in general1 by the term agricultural products is meant not only the direct products of the farm1 orchard and forest1 but also the modified products thereof and the results of manufacture applied to the raw materials4 ,thus1 not only the grain and straw of wheat are proper materials for agricultural analysis1 but also flour and bran1 bread and cakes made therefrom4 ,in the case of maize and barley1 the manufactured products may extend much further1 for not only do we find starch and malt1 but also alcohol and beer falling within the scope of our work4 ,in respect of animal products1 the agricultural analyst may be called on to investigate the subject of leather and tanning2 to determine the composition of meat1 milk and butter2 to pass upon the character of lard1 oleomargarine1 and1 in general1 to determine as fully as possible the course of animal food in all its changes between the field1 the packing house and the kitchen4 #c4 ,limitations of ,work4--,it is evident from the preceding paragraph1 that in order to keep the magnitude of this volume within the limits fixed for a single volume the text must be rigidly confined to the fundamental principles and practice of agricultural analysis4 ,the interesting region of pharmacy and allied branches1 in respect of plant analysis1 can find no description here1 and in those branches of technical chemistry1 where the materials of elaboration are the products of the field only a superficial view can be given4 ,the main purpose and motive of this volume must relate closely to the more purely agricultural processes4 #d4 ,general ,manipulations4--,there are certain analytical operations which are more or less of a general nature1 that is1 they are of general application without reference to the character of the material at hand4 ,among these may be mentioned the determination of moisture and of ash1 and the estimation of matters soluble in ether1 alcohol and other solvents4 ,these processes will be first described4 ,preliminary to these analytical steps it is of the utmost importance that the material be properly prepared for examination4 ,in general1 this is accomplished by drying the samples until they can be ground or crushed to a fine powder1 the attrition being continued until all the particles are made to pass a sieve of a given fineness4 ,the best sieve for this purpose is one having circular apertures half a millimeter in diameter4 ,some products1 both vegetable and animal1 require to be reduced to as fine a state as possible without drying4 ,in such instances1 passing the product through a sieve is obviously impracticable4 ,special grinding and disintegrating machines are made for these purposes and they will be described further on4 ,there are some agricultural products which have to be prepared for examination in special ways and these methods will be given in connection with the processes for analyzing the bodies referred to4 ,nearly all the bodies1 however1 with which the analyst will be concerned1 can be prepared for examination by the general methods about to be described4 #e4 ,preparation of the ,sample4 7a7 ,vegetable ,substances4--,for all processes of analysis not executed on the fresh sample1 substances of a vegetable nature should1 if in a fresh state1 be dried as rapidly as possible to prevent fermentative changes4 ,it is often of interest to determine the percentage of moisture in the fresh sample4 ,for this purpose a representative portion of the sample should be rapidly reduced to as fine a condition as possible4 ,to accomplish this it should be passed through a shredding machine1 or cut by scissors or a knife into fine pieces4 ,a few grams of the shredded material are dried in a flat-bottomed dish at progressively increasing temperatures1 beginning at about #fj and ending at from #ajj to #aaj4 ,the latter temperature should be continued for only a short time4 ,the principle of this process is based upon the fact that if the temperature be raised too high at first1 some of the moisture in the interior cells of the vegetable substance can be occluded by the too rapid desiccation of the exterior layers which would take place at a high temperature4 ,the special processes for determining moisture will be given in another place4 ,the rest of the sample should be partly dried at a lower temperature or air-dried4 ,in the case of fodders and most cattle foods the samples come to the analyst in a naturally air-dried state4 ,when grasses are harvested at a time near their maturity they are sun-dried in the meadows before placing in the stack or barn4 ,such sun-dried samples are already in a state fit for grinding4 ,green grasses and fodders should be dried in the sun1 or in a bath at a low temperature from #ej to #fj until all danger of fermentative action is over1 and then air- or sun-dried in the usual way4 ,seeds and cereals usually reach the analyst in a condition suited to grinding without further preliminary preparation4 ,fruits and vegetables present greater difficulties4 ,containing larger quantities of water1 and often considerable amounts of sugar1 they are dried with greater difficulty4 ,the principles which should guide all processes of drying are those already mentioned1 viz41 to secure a sufficient degree of desiccation to permit of fine grinding and at a temperature high enough to prevent fermentative action1 and yet not sufficiently high to cause any marked changes in the constituents of the vegetable organism4 7b7 ,animal ,substances4--,the difficulties connected with the preliminary treatment of animal substances are far greater than those just mentioned4 ,such samples are composed of widely differing tissues1 blood1 bone1 tendon1 muscle and adipose matters1 and all the complex components of the animal organism are to be considered4 ,the whole animal may be presented for analysis1 in which case the different parts composing it should be separated and weighed as exactly as possible4 ,where only definite parts are to be examined it is best to separate the muscle1 bone1 and fat as well as may be1 before attempting to reduce the whole to a fine powder4 ,the soft portions of the sample are to be ground as finely as possible in a meat or sausage cutter4 ,the bones are crushed in some appropriate manner1 and thus prepared for further examination4 ,where the flesh and softer portions are to be dried and finely ground1 the presence of fat often renders the process almost impossible4 ,in such cases the fat must be at least partially removed by petroleum or other solvent4 ,in practically fat-free samples the material1 after grinding in a meat cutter1 can be partially dried at low temperatures from #fj to #ge1 and afterwards ground in much the same manner as is practiced with vegetable substances4 ,as is the case with the preliminary treatment of vegetable matters1 it is impossible to give any general directions of universal applicability4 ,the tact and experience of the analyst in all these cases are better than any dicta of the books4 ,in some instances1 as will appear further on1 definite directions for given substances can be given1 but in all cases the general principles of procedure are on the lines already indicated4 #f4 ,preserving ,samples4--,in most cases1 as is indicated in the foregoing paragraphs1 the sample may be dried before grinding to such a degree as to prevent danger from fermentation or decay4 ,the fine-ground samples are usually preserved in glass-stoppered bottles1 carefully marked or numbered4 ,in some cases it is advisable to sterilize the bottles after stoppering1 by subjecting them to a temperature of #ajj for some time4 ,in the case of cereals assurance should be had that the samples do not contain the eggs of any of the pests that often destroy these products4 ,as a rule1 samples should be kept for a time after the completion of the analytical work1 and this is especially true in all cases where there is any prospect of dispute or litigation4 ,in general it may be said1 that samples should be destroyed only when they are spoiled1 or when storage room is exhausted4 #g4 ,collecting ,samples4--,when possible1 the analyst should be his own collector4 ,there is often as much danger from data obtained on non-representative samples as from imperfect manipulation4 ,when personal supervision is not possible1 the sample when received1 should be accompanied by an intelligible description of the method of taking it1 and of what it represents4 ,in all cases the object of the examination must be kept steadily in view4 ,where comparisons are to be made the methods of collecting must be rigidly the same4 ,the processes of analysis1 as conducted with agricultural products1 are tedious and difficult4 ,the absolutely definite conditions that attend the analysis of mineral substances1 are mostly lacking4 ,the simple determinations of carbon1 hydrogen1 nitrogen and sulfur1 which are required in the usual processes of organic analysis1 are simplicity itself when compared with the operations which have to be performed on agricultural products to determine their character and their value as food and raiment4 ,we have to do here with matters on which the sustenance1 health and prosperity of the human race are more intimately concerned than with any other of the sciences4 ,this fact also emphasizes the necessity for care in collecting the materials on which the work is to be performed4 #h4 ,grinding ,samples4--,in order to properly conduct the processes of agricultural analysis it is important to have the sample finely ground4 ,this arises both from the fact that such a sample is apt to contain an average content of the various complex substances of which the material under examination is composed1 and because the analytical processes can be conducted with greater success upon the finely divided matter4 ,in mineral analysis it is customary to grind the sample to an impalpable powder in an agate mortar4 ,with agricultural products1 however1 such a degree of fineness is difficult to attain1 and moreover1 is not necessary4 ,there is a great difference of opinion among analysts respecting the degree of fineness desirable4 ,in some cases we must be content with a sample which will pass a sieve with a millimeter mesh2 in fact it may be found impossible1 on account of the stickiness of the material1 to sift it at all4 ,in such cases a thorough trituration1 so as to form a homogeneous mass will have to be accepted as sufficient4 ,where bodies can be reduced to a powder however1 it is best to pass them through a sieve with circular perforations half a millimeter in diameter4 ,a finer degree of subdivision than this is rarely necessary4 #i4 ,the ,grinding ,apparatus4--,the simplest form of apparatus for reducing samples for analysis to a condition suited to passing a fine sieve is a mortar4 ,where only a few samples are to be prepared and in small quantities1 it will not be necessary to provide anything further4 ,after the sample is well disintegrated it is poured on the sieve and all that can pass is shaken or brushed through4 ,the sieve is provided with a receptacle1 into which it fits closely1 to avoid loss of any particles which may be reduced to a dust4 ,the top of the sieve1 when shaken1 may also be covered if there be any tendency to loss from dust4 ,any residue failing to pass the sieve is returned to the mortar and the process thus repeated until all the material has been secured in the receiver4 ,the particles more difficult of pulverization are often different in structure from the more easily pulverized portions1 and the sifted matter must always be carefully mixed before the subsample is taken for examination4 ,often the materials1 or portions thereof1 will contain particles tough and resistant to the pestle1 but the operator must have patience and persistence1 for it is highly necessary to accurate work that the whole sample be reduced to proper size4 ,illustration3 ,,figure #a4 ,,mill ,,for ,,grinding ,,dry ,,samples4 ,where many samples are to be prepared1 or in large quantities1 mills should take the place of mortars4 ,for properly air-dried vegetable substances1 some form of mill used in grinding drugs may be employed4 ,grinding surfaces of chilled corrugated steel are to be preferred4 ,the essential features of such a mill are that it be made of the best material1 properly tempered1 and that the parts be easily separated for convenience in cleaning4 ,the grinding surfaces must also be so constructed and adjusted as to secure the proper degree of fineness4 ,in fig4 #a is shown a mill of rather simple construction1 which has long been in satisfactory use in this laboratory4 ,small mills may be operated by hand power1 but when they are to be used constantly steam power should be provided4 ,in addition to the removal of nearly all the moisture by air-drying there are many oleaginous seeds which cannot be finely ground until their oil has been removed4 ,for this purpose the grinding surfaces of the mill are opened so that the seeds are only coarsely broken in passing through4 ,the fragments are then digested with light petroleum in a large flask1 furnished with a reflux condenser4 ,after digestion the fragments are again passed through the mill adjusted to break them into finer particles4 ,the alternate grinding and digestion are thus continued until the pulverization is complete4 ,on a small specially prepared sample the total content of oil is separately determined4 ,fresh animal tissues are best prepared for preliminary treatment by passing through a sausage mill4 ,the partially homogeneous mass thus secured should be dried at a low temperature and reground as finely as possible4 ,where much fat is present it may be necessary to extract it as mentioned above1 in the case of oleaginous seeds4 ,in such cases both the moisture and fat in the original material should be determined on small specially prepared samples with as great accuracy as possible4 ,bones1 hoofs1 horns1 hair and hides present special difficulties in preparation1 which the analyst will have to overcome with such skill and ingenuity as he may possess4 ,the analyst will find many specially prepared animal foods already in a fairly homogeneous form1 such as potted and canned meats1 infant and invalid foods1 and the like4 ,even with these substances1 however1 a preliminary grinding and mixing will be found of advantage before undertaking the analytical work4 ,many cases will arise which are apparently entirely without the classification given above4 ,but even in such instances the analyst should not be without resources4 ,frequently some dry inert substance may be mixed with the material in definite quantities1 whereby it is rendered more easily prepared4 ,perhaps no case will be presented where persistent and judicious efforts to secure a fairly homogeneous sample for analysis will be wholly unavailing4 ,illustration3 ,,figure #b4 ,,comminutor ,,for ,,green ,,samples4 ,in the case of green vegetable matters which require to be reduced rapidly to a fine state of subdivision in order to secure even a fairly good sample some special provision must be made4 ,this is the case with stalks of maize and sugar cane1 root crops1 such as potatoes and beets1 and green fodders1 such as clover and grasses4 ,the chopping of these bodies into fine fodders by hand is slow and often impracticable4 ,the particles rapidly lose moisture and it is important to secure them promptly as in the preparation of beet pulp for polarization4 ,for general use we have found the apparatus shown in fig4 #b quite satisfactory in this laboratory4 ,it consists of a series of staggered circular saws carried on an axis and geared to be driven at a high velocity1 in the case mentioned1 #a1djj revolutions per minute4 ,the green material is fed against the revolving saws by the toothed gear-work shown1 and is thus reduced to a very fine pulp1 which is received in the box below4 ,stalks of maize1 green fodders1 sugar canes1 beets and other fresh vegetable matters are by this process reduced to a fine homogeneous pulp1 suited for sampling and for analytical operations4 ,such pulped material can also be spread in a fine layer and dried rapidly at a low temperature1 thus avoiding danger of fermentative changes when it is desired to secure the materials in a dry condition or to preserve them for future examination4 ,samples of sorghum cane1 thus pulped and dried1 have been preserved for many years with their sugar content unchanged4 ,illustration3 ,,figure #c4 ,,rasp ,,for ,,sugar ,,beets4 ,such a machine is also useful in preparing vegetable matter for the separation of its juices in presses4 ,samples of sugar cane1 sugar beets1 apples and other bodies of like nature can thus be prepared to secure their juices for chemical examination4 ,such an apparatus we have found is fully as useful and indispensable in an agricultural laboratory as a drug mill for air-dried materials4 ,it is often desirable in the preparation of roots for sugar analysis to secure them in a completely disintegrated state1 that is with the cellular tissues practically all broken4 ,such a pulped material can be treated with water and the sugar juices it contains thus at once distributed to all parts of the liquid mass4 ,the operation is known as instantaneous diffusion4 ,the pulp of the vegetable matter is thus introduced into the measuring flask along with the juices and the content of sugar can be easily determined4 ,several forms of apparatus have been devised for this purpose1 one of which is shown in fig4 #c4 ,this process1 originally devised by ,pellet1 has come into quite general use in the determination of the sugar content of beets4#a ,it is observed that it can be applied to other tubers1 such as the turnip1 potato1 artichoke1 etc4 ,it is desirable1 therefore1 that an agricultural laboratory be equipped with at least three kinds of grinding machines2 viz41 first1 the common drug mill used for grinding seeds1 air-dried fodders1 and the like2 second1 a pulping machine like the system of staggered saws above described for the purpose of reducing green vegetable matter to a fine state of subdivision1 or one like the pellet rasp for tubers2 third1 a mill for general use such as is employed for making sausages from soft animal tissues4 ,illustration3 ,,figure #d4 ,,dreef ,,grinding ,,apparatus4 #aj4 ,grinding ,apparatus at ,halle ,station4--,the machine used at the ,halle station for grinding samples for analysis is shown in ,fig4 #d4b ,it is so adjusted as to have both the upper and lower grinding surfaces in motion4 ,the power is transmitted through the pulley ,d1 which is fixed to an axis carrying also the inner grinding attachment ,b4 ,through ,c1 ,c1 ,c1 and ,c1 the reverse motion is transmitted to the outer grinder ,a4 ,by means of the lever ,e the two grinding surfaces can be separated when the mill is to be cleaned4 ,the dree mill above described is especially useful for grinding malt1 dry brewers' grains1 cereals for starch determinations and similar dry bodies4 ,it is not suited to grinding oily seeds and moist samples4 ,these1 according to the ,halle methods1 are rubbed up in a mortar until of a size suited to analysis1 and samples such as moist residues1 wet cereals1 mashes1 beet cuttings1 silage1 etc41 are dried before grinding4 ,if it be desired to avoid the loss of acids which may have been formed during fermentation1 about ten grams of magnesia should be thoroughly incorporated with each kilogram of the material before drying4 #aa4 ,preliminary ,treatment of ,fish4--,the method used by ,atwater in preparing fish for analysis is given below4#c ,the same process may also be found applicable in the preparation of other animal tissues4 ,the specimens1 when received at the laboratory1 are at once weighed4 ,the flesh is then separated from the refuse and both are weighed4 ,there is always a slight loss in the separation1 due to evaporation and to slimy and fatty matters and small fragments of the tissues which adhere to the hands and the utensils employed in preparing the sample4 ,perfect separation of the flesh from the other parts of the fish is difficult1 but the loss resulting from imperfect separation is small4 ,the skin of the fish1 although it has considerable nutritive value1 should be separated with the other refuse4 ,the partial drying of the flesh for securing samples for analytical work is accomplished by chopping it as finely as possible and subjecting from fifty to one hundred grams of it for a day to a temperature of #if in an atmosphere of hydrogen4 ,after cooling and allowing to stand in the open air for twelve hours1 the sample is again weighed1 and then ground to a fine powder and made to pass a sieve with a half millimeter mesh4 ,if the samples be very fat they cannot be ground to pass so fine a sieve4 ,in such a case a coarser sieve may be used or the sample reduced to as fine and homogeneous a state as possible1 and bottled without sifting4 ,the reason for drying in hydrogen is to prevent oxidation of the fats4 ,as will be seen further on1 however1 such bodies can be quickly and accurately dried at low temperatures in a vacuum1 and thus all danger of oxidation be avoided4 ,in fact1 the preliminary drying of all animal and vegetable tissues1 where oxidation is to be feared1 can be safely accomplished in a partial vacuum by methods to be described in another place4 ,in order to be able to calculate the data of the analysis to the original fresh state of the substance1 a portion of the fresh material should have its water quantitively determined as accurately as possible4 ,,drying ,,organic ,,bodies4 #ab4 ,volatile ,bodies4--,in agricultural analysis it becomes necessary to determine the percentage of bodies present in any given sample which is volatile at any fixed temperature4 ,the temperature reached by boiling water is the one which is usually selected4 ,it is true that this temperature varies with the altitude and within somewhat narrow limits at the same altitude1 due to variations in barometric pressure4 ,as the air pressure to which any given body is subjected1 however1 is a factor in the determination of its volatile contents1 it will be seen that within the altitudes at which chemical laboratories are found1 the variations in volatile content will not be important4 ,this arises from the fact that while water boils at a lower temperature1 as the height above the sea level increases1 the corresponding diminished air pressure permits a more ready escape of volatile matter4 ,as a consequence1 a body dried to constant weight at sea level1 where the temperature of boiling water is #ajj1 will show the same percentage of volatile matter as if dried at an altitude where water boils at #ii4 ,when1 therefore1 it is desirable to determine the volatile matter in a sample approximately at #ajj1 it is better to direct that it be done in a space surrounded by steam at the natural pressure rather than at exactly #ajj1 a temperature somewhat difficult to constantly maintain4 ,however1 where it is directed or desired to dry to constant weight exactly at #ajj1 it can be accomplished by means of an air-bath or by a water-jacketed-bath under pressure1 or to which enough solid matter is added to raise the boiling-point to #ajj4 ,it is not often1 however1 that it is worth while to make any special efforts to secure a temperature of #ajj4 ,when bodies are to be dried at temperatures above #ajj1 such as #aje1 #aaj1 and so on1 an air-bath is the most convenient means of securing the desired end4 ,the different kinds of apparatus to be employed will be described in succeeding paragraphs4 #ac4 ,drying at the ,temperature of ,boiling ,water4--,the best apparatus for this process is so constructed as to have an interior space entirely surrounded with boiling water or steam1 with the exception of the door by which entrance is gained thereto4 ,the metal parts of the apparatus are constructed of copper1 and to keep a constant level of water and avoid the danger of evaporating all the liquid1 it is advisable to have a reflux condenser attached to the apparatus4 ,it is also well to secure entrance to the interior drying oven1 not only by the door1 but also by small circular openings1 which serve both to hold a thermometer and to permit of the aspiration of a slow stream of dry air through the apparatus during the progress of desiccation4 ,the gaseous bodies formed by the volatilization of the water and other matters are thus carried out of the drying box and the process thereby accelerated4 ,the bath should be heated by a burner so arranged as to distribute the flame as evenly as possible over the base4 ,a single lamp1 while it will boil the water in the center1 will not keep it at the boiling-point on the sides4 ,the temperature of the interior of the bath will not therefore reach #ajj4 ,the interior of the oven should be coated with a non-detachable carbon paint to promote the radiation of the heat from its walls1 as well as to protect the parts from oxidation where acid fumes are produced during desiccation4 ,instead of a reflux condenser a constant water level may be maintained in the bath by means of a mariotte bottle or other similar device4 ,illustration3 ,,figure #e4 ,,water-,,jacketed ,,drying ,,oven4 ,when a bath of this kind is arranged for use with a partial vacuum1 it should be made cylindrical in shape1 with conical ends1 as shown in fig4 #e1 in order to bear well the pressure to which it is subjected4 ,among the many forms of steam-baths offered1 the analyst will have but little difficulty in selecting one suited to his work4 ,to avoid radiation the exterior of the apparatus should be covered with a non-conducting material4 ,illustration3 ,,figure #f4 ,,thermostat ,,for ,,steam-,,bath4 #ad4 ,drying ,in a ,closed ,water ,oven4--,when it is desired to keep the temperature of a drying oven exactly at #ajj instead of at the heat of boiling water1 a closed water oven with a thermostat is to be employed4 ,the oven should be so constructed as to secure a free circulation of the water about the inner space4 ,since as a rule the water between the walls of the apparatus will be subjected to a slight pressure1 these walls should be made strong1 or the cylindrical form of apparatus should be used4 ,the thermostat used by the ,halle ,station is shown in ,fig4 #f4d ,a shaped tube1 with a bulb on one arm and a lateral smaller tube sealed on the other1 is partly filled with mercury and connected by rubber tubes on the right with the gas supply1 and on the left with the burner4 ,the end carrying the bulb is connected directly by a rubber and metal tube with the water space of the oven4 ,this device is provided with a valve which is left open until the temperature of the drying space reaches about #ie4 ,the tube conducting the gas is held in the long arm of the by means of a cork through which it passes air-tight and yet is loose enough to permit of its being moved4 ,its lower end is provided with a long shaped slit4 ,when the valve leading to the water space is closed and the water reaches the boiling point1 the pressure of the vapor depresses the mercury in the bulb arm of the and raises it in the other4 ,as the mercury rises it closes the wider opening of the shaped slit1 thus diminishing the flow of gas to the burner4 ,by moving the gas entry tube up or down a position is easily found in which the temperature of the drying space1 as shown by the thermometer1 is kept accurately and constantly at #ajj4 ,in a bath arranged in this way a steam condenser is not necessary4 ,since1 however1 in laboratories which are not at a higher altitude than #a1jjj feet the boiling-point of water is nearly #ajj1 it does not seem necessary to go to so much trouble to secure the exact temperature named4 ,there could be no practical difference in the percentage of moisture determined at #ajj1 and at the boiling-point of water at a temperature not more than #a lower4 #ae4 ,drying in an ,air-,bath4--,in drying a substance in a medium of hot air surrounded by steam1 as has been described1 the process is1 in reality1 one of drying in air4 ,the apparatus usually meant by the term air-bath1 however1 has its drying space heated directly by a lamp1 or indirectly by a stratum of hot air occupying the place of steam in the oven already described4 ,the simplest form of the apparatus is a metal box1 usually copper1 heated from below by a lamp4 ,in the jacketed forms the currents of hot air produced directly or indirectly by the lamp are conducted around the inner drying oven1 thus securing a more even temperature4 ,the bodies to be dried are held on perforated metal or asbestos shelves in appropriate dishes1 and the temperature to which they are subjected is determined by a thermometer1 the bulb of which is brought as near as possible to the contents of the dish4 ,one advantage of the air-bath is in being able to secure almost any desired temperature from that of the room to one of #aej or even higher4 ,its chief disadvantage lies in the difficulty of securing and maintaining an even temperature throughout all parts of the apparatus4 ,radiation from the sides of the drying oven should be prevented by a covering of asbestos or other non-combustible and non-conducting substance4 ,the burner employed should be a broad one and give as even a distribution of the heat as possible over the bottom of the apparatus4 ,illustration3 ,,figure #g4 ,,spencer',s ,,drying ,,oven4 #af4 ,spencer's ,air-,drying ,oven4--,in order to secure an even distribution of the heat in the desiccating space of the oven1 ,spencer has devised an apparatus1 shown in the figure1 in which the temperature is maintained evenly throughout the apparatus by means of a fan4#e ,the oven has a double bottom1 the space between the two bottoms being filled with air4 ,the sides are also double1 the space between being filled with plaster4 ,the fan is driven by a toy engine connected with the compressed air service or other convenient method4 ,thermometers placed in different parts of the apparatus1 while in use1 show a rigidly even heat at all points so long as the fan is kept in motion4 ,the actual temperature desired can be controlled by a gas regulator4 ,this form of apparatus is well suited to drying a large number of samples at once4 ,portions of liquids and viscous masses may also be dried by enclosing them in bulbs and connecting with a vacuum4 ,spencer's oven can also be used to advantage in drying viscous liquids in a partial vacuum4 ,for this purpose the flask ,a1 ,fig4 #g1 containing the substance is made with a round bottom to resist the atmospheric pressure4 ,its capacity is conveniently from #aej to #bjj cubic centimeters4 ,it is closed with a rubber stopper carrying a trap1 ,h ,h1 to keep the evaporated water from falling back4 ,the details of the construction of the trap ,h are shown at the right of the figure4 ,the vapors enter at the lateral orifice1 just above the bulb1 while the condensed water falls back into the bulb instead of into the flask ,a4 ,a series of flasks can be used at once connected through the stopcocks ,g with the circular tube ,e leading to the vacuum4 ,a water pump easily exhausts the apparatus1 maintaining a vacuum of about twenty-seven inches4 ,the hot air in the oven is kept in motion by the fan ,b1 thus ensuring an even temperature in every part4 ,the flask ,a may be partly filled with sand or pumice stone before the addition of the samples to be dried1 and the weight of water lost is determined by weighing ,a before and after desiccation4 ,if it be desired to introduce a slow current of dry air or some inert gas into ,a1 it is easily accomplished by passing a small tube1 connected with the dry air or gas supply1 through the rubber stopper and extending it into the flask as far as possible without coming into contact with the contents4 #ag4 ,drying ,under ,diminished ,air ,pressure4--,the temperature at which any given body loses its volatile products is conditioned largely by the pressure to which it is subjected4 ,at an air pressure of #gfj millimeters of mercury1 water boils at #ajj but it is volatilized at all temperatures4 ,as the pressure diminishes the temperature at which a body loses water at a given rate falls4 ,this is a fact of importance to be considered in drying many agricultural products4 ,this is especially true of those containing oils and sugars1 nearly the whole number4 ,invert sugar especially is apt to suffer profound changes at a temperature of #ajj1 the levulose it contains undergoing partial decomposition4 ,oils are prone to oxidation and partial decomposition at high temperatures in the presence of oxygen4 ,in drying in a partial vacuum therefore a double advantage is secured1 that of a lower temperature of desiccation and in presence of less oxygen4 ,it is not necessary to have a complete vacuum4 ,there are few organic products which cannot be completely deprived of their volatile matters at a temperature of from #gj to #hj in a partial vacuum in which the air pressure has been diminished to about one-quarter of its normal force4 ,illustration3 ,,figure #h4 ,,electric ,,vacuum ,,drying ,,oven4 #ah4 ,electric ,drying-,bath4--,the heat of an electric current can be conveniently used for drying in a partial vacuum by means of the simple device illustrated in ,fig4 #h4 ,in ordering a heater of this kind the voltage of the current should be stated4 ,the current in use in this laboratory has a voltage of about #abj1 and is installed on the three wire principle4 ,it is well to use a rheostat with the heater in order to control the temperature within the bell jar4 ,the ground rim of the bell jar rests on a rubber disk placed on a thick ground glass or a metal plate1 making an air-tight connection4 ,a disk of asbestos serves to separate the heater from the dish containing the sample1 in order to avoid too high a temperature4 #ai4 ,steam ,coil ,apparatus4--,for drying at the temperature of superheated steam1 it is convenient to use an apparatus furnished with layers or coils of steam pipes4 ,the drying may be accomplished either in the air or in a vacuum4 ,in this laboratory a large drying oven1 having three shelves of brass steam-tubes and sides of non-conducting material1 is employed with great advantage4 ,the series of heating pipes is so arranged as to be used one at a time or collectively4 ,each series is furnished with a separate steam valve1 and is provided with a trap to control the escape of the condensed vapors4 ,in the bottom of the apparatus are apertures through which air can enter1 which after passing through the interior of the oven escapes through a ventilator at the top4 ,with a pressure of forty pounds of steam to the square inch and a free circulation of air1 the temperature on the first shelf of the apparatus is about #ih2 on the second from #ajc to #ajd1 and on the third about #ajj4 ,the vessels containing the bodies to be dried are not placed directly on the brass steam pipes1 but the latter are first covered with thick perforated paper or asbestos4 ,for drying large numbers of samples1 or large quantities of one sample1 such an apparatus is almost indispensable to an agricultural laboratory4 ,illustration3 ,,figure #i4 ,,steam ,,coil ,,drying ,,oven4 ,a smaller apparatus is shown in ,fig4 #i4 ,the heating part ,g is made of a small brass tube arranged near the bottom in a horizontal coil and continued about the sides in a perpendicular coil4 ,bodies placed on the horizontal shelf are thus entirely surrounded by the heating surfaces except at the top4#f ,the steam pipe ,s is connected with the supply by the usual method1 and the escape of the condensation is controlled either by a valve or trap in the usual way4 ,the whole apparatus is covered by a bell jar ,b1 resting on a heavy cast-iron plate ,p1 through which also the ends of the brass coil pass4 ,the upper surface of the iron plate may be planed1 or a planed groove may be cut into it1 to secure the edge of the bell jar4 ,when the air is to be exhausted from the apparatus1 a rubber washer should be placed under the rim of the bell jar4 ,the latter piece of apparatus may either be closed1 as shown in the figure1 by a rubber stopper1 or it is better1 though not shown1 to have a stopper with three holes4 ,one tube passes just through the stopper and is connected with the vacuum2 the second passes to the bottom of the apparatus and serves to introduce a slow stream of dry air or of an inert gas during the desiccation4 ,the third hole is for a thermometer4 ,when no movement of the residual gas in the apparatus is secured1 a dish containing strong sulfuric acid ,s' is placed on the iron plate and under the horizontal coil1 as is shown in the figure4 ,the sulfuric acid so placed does not reach the boiling-point of water1 and serves to absorb the aqueous vapors from the residual air in the bell jar4 ,by controlling the steam supply the desiccation of a sample can be secured in the apparatus at any desired temperature within the limit of the temperature of steam at the pressure used4 ,where no steam service is at hand a strong glass flask may be used as a boiler1 in which case the trap end of the coil must be left open4 ,the vacuum may be supplied by an air or bunsen pump4 ,when a vacuum is not used an atmosphere of dry hydrogen may be supplied through ,h4 ,illustration3 ,,figure #aj4 ,,carr',s ,,vacuum ,,drying ,,oven4 ,illustration3 ,,figure #aj4 7,,bis7 ,,vacuum ,,oven ,,open4 #bj4 ,carr's ,vacuum ,oven4--,a convenient drying oven has been devised in this laboratory by ,carr4#g ,it is made of a large tube1 preferably of brass4 ,the tube may be from six to nine inches in diameter and from twelve to fifteen inches long4 ,one end is closed air-tight by a brass end-piece attached by a screw1 or brazed4 ,the other end is detachable and is made air-tight by ground surfaces and a soft washer4 ,in the figure this movable end-piece is shown attached by screw-nuts1 but experience has shown that these are not necessary4 ,on the upper longitudinal surfaces are apertures for the insertion of a vacuum gauge and for attachment to a vacuum apparatus4 ,in the figure the thermometer and aperture for introducing dry air or an inert gas are shown in the movable end disk1 but they would be more conveniently placed in the fixed end4 ,the oven is heated below by a gas burner1 which conveniently should be as long as the oven4 ,the heat is not allowed to strike the brass cylinder directly1 but the latter is protected by a piece of asbestos paper4 ,the temperature inside of the oven can be easily kept practically constant by means of a gas regulator1 not shown in the figure1 or by a little attention to the lamp4 ,for a vacuum of twenty inches a temperature of about #hj should be maintained4 ,when the vacuum is more complete a lower temperature can be employed4 ,this apparatus is simple in construction1 strong1 cheap1 and highly satisfactory in use4 #ba4 ,drying in ,hydrogen4--,in some of the processes of agricultural analysis it becomes important to dry the sample in hydrogen or other inert gas4 ,this may be accomplished by introducing the dry gas desired into some form of the apparatus already described4 ,the drying may either be accomplished in an atmosphere of hydrogen practically at rest or in a more limited quantity of the gas in motion4 ,the latter method is to be preferred by reason of its greater rapidity4 ,the analyst has at his command many forms of apparatus designed for the purpose mentioned above4 ,it will be sufficient here to describe only two1 devised particularly for agricultural purposes4 ,the first one of these1 designed by the author1 was intended especially for drying the samples of fodders for analysis according to the methods of the ,association of ,agricultural ,chemists4#h ,illustration3 ,,figure #aa4 ,,apparatus ,,for ,,drying ,,in ,a ,,current ,,of ,,hydrogen4 ,for the purpose of drying materials contained in flasks and tubes in a current of hydrogen the apparatus shown in ,fig4 #aa is used4 ,this apparatus consists of a circular box1 ,b1 conveniently made of galvanized iron1 having a movable cover1 ,s1 fitted for the introduction of steam into the interior of the apparatus4 ,condensed steam escapes at ,w4 ,a stream of perfectly pure and dry hydrogen enters at ,h1 passes up through the material to be dried1 down through the bulb ,v1 containing sulfuric acid1 and follows the direction of the arrows through the rest of the apparatus4 ,the stream of hydrogen is thus completely dried by passing through bulbs containing sulfuric acid1 on the way from one piece of the apparatus to the other4 ,a1 represents a flask such as is used1 with the extraction apparatus described4 ,the apparatus which we have used will hold eight tubes or flasks at a time1 and thus a single stream of hydrogen is made to do duty eight times in drying eight separate samples4 ,the great advantage of the apparatus is in the fact that the stream of hydrogen must pass over and through the substance to be dried4 ,in order to prevent any sulfuric acid from being carried forward into the next tube the bulb ,k1 above the sulfuric acid1 may be filled with solid pieces of soda or potash4 ,this apparatus has been in use for a long time and no accidents from sulfuric acid being carried forward have occurred1 and there is no danger1 provided the stream of hydrogen is kept running at a slow rate4 ,if1 however1 by any accident the stream of hydrogen should be admitted with great rapidity1 particles of the sulfuric acid might be carried forward and spoil the next sample4 ,to avoid any such accident as this the proposal to introduce the potash bulb has been made4 ,the apparatus works with perfect satisfaction1 and it is believed that when properly adjusted check weighings can be made by weighing the bulbs1 showing their increase in weight1 which will give the volatile matter1 and weighing the flasks or tubes1 which will show the loss of weight4 ,the only chance for error in weighing the bulbs is that some of the volatile matter may be material which is not dissolved in sulfuric acid1 and is thus carried on and out of the apparatus4 ,the blackening of the sulfuric acid in the bulbs1 in the drying of all forms of organic matter1 shows that the loss in weight of such bodies is not due to water alone1 but also to organic volatile substances1 which are capable of being decomposed by the sulfuric acid1 thus blackening it4 #bb4 ,caldwell's ,hydrogen ,drying-,bath4--,an excellent device for drying in hydrogen has been described by ,caldwell4#i ,a vessel of copper or other suitable material serves to hold the tubes containing the samples to be dried4 ,it should be about twenty-four centimeters long1 fifteen high1 and eight wide4 ,this vessel is contained in another made of the same material and of the dimensions shown in the figure4 ,on one side the edge of this containing vessel may not be more than one centimeter high and the bath should rest against it4 ,the other side is made higher to form a support for the drying tubes as indicated4 ,illustration3 ,,figure #ab4 ,,caldwell',s ,,hydrogen ,,drying ,,apparatus4 ,the tube containing the substance a d is made of glass and may be closed by the ground stoppers c b or the tube stoppers e f4 ,at a it carries a perforated platinum disk for holding the filtering felt4 ,the tube should be about thirteen centimeters long and have an internal diameter of about twenty millimeters4 ,with its stoppers it should weigh only a little over thirty grams4 ,the asbestos felt should not be thick enough to prevent the free passage of gas4 ,passing diagonally through the bath are metal tubes1 preferably made of copper1 and of such a size as just to receive the glass drying tubes4 ,if these be a little loose they should be made tight by wrapping them with a narrow coil of paper at either end of the tubular receptacle4 ,the entrance of cold air between the glass tube and its metal holder is thus prevented1 and the glass tube is held firmly in position4 ,the glass tube should be weighed with its two solid stoppers4 ,afterwards the sample1 about two grams1 is placed on the asbestos felt and the stoppers replaced and the whole reweighed4 ,the exact weight of the sample is thus obtained4 ,the solid stoppers are then removed and the tube stoppers inserted4 ,the lower end of the tube is then connected with the supply of dry hydrogen4 ,the upper tube stopper is connected by a rubber tube with a small bottle containing sulfuric acid through which the escaping hydrogen is made to bubble4 ,a double purpose is thus secured2 moisture is kept from entering the drying tube and the rate at which the hydrogen is passing is easily noted4 ,after the drying is completed the solid stoppers are again inserted1 the tube cooled in a desiccator and weighed4 ,the loss of weight is entered as water4 ,the tube containing the sample can afterwards be put into an extractor and treated with ether or petroleum in the manner hereafter described4 ,this apparatus requires more hydrogen than the one previously described1 but it is rather simple in construction1 is easily controlled1 and has given satisfactory results4 ,illustration3 ,,figure #ac4 ,,liebig',s ,,ente4 #bc4 ,drying in ,liebig's ,tubes4--,in drying samples1 especially of fodders1 the method practiced at the ,halle ,station is to place them in drying tubes1 the form of which is shown in ,fig4 #ac4 ,a stream of illuminating gas1 previously dried by passing over sulfuric acid and calcium chlorid1 is directed through the tubes4#aj ,many of these tubes can be used at once1 arranged as shown in ,fig4 #ad4 ,when the air is all driven out the stream of gas can be ignited so as to regulate the flow properly by the size of the flame4 ,the tubes are held in drying ovens1 as shown in the figure1 the temperature of which should be kept at #aje-ajg4 ,the drying should be continued for eight or ten hours4 ,at the end of this time the gas in the tube is to be expelled by a stream of dry air and the tubes cooled in a desiccator and weighed4 ,there are few advantages in this method not possessed by the processes already described4 ,the samples1 moreover1 are not left in a condition for further examination1 either by incineration or extraction4 ,illustration3 ,,figure #ad4 ,,drying ,,apparatus ,,used ,,at ,,the ,,halle ,,station4 #bd4 ,wrampelmayer's ,drying ,oven4--,the apparatus used at the ,wageningen ,station1 in ,holland1 for drying agricultural samples1 was devised by ,wrampelmayer and is shown in ,fig4 #ae4 ,the oven is so constructed as to permit of drying in a stream of inert gas4 ,illuminating gas is let into the drying space of the oven through the tube ,a ,b4 ,at ,b the entering gas is heated by the same lamp which boils the liquid in the water space of the apparatus4 ,the hot gas is dried in the calcium chlorid tube c and then passes into the oven at ,d4 ,at ,e it leaves the apparatus and is thence conducted to the lamp ,f1 used for heating the bath4 ,the lamp should be closed by a wire gauze diaphragm to prevent any possible explosion by reason of any admixture with the air in the oven4 ,the condensation of the aqueous vapors is effected by means of the condenser ,g4 ,in the drying space is a small shelf holder1 which1 by means of the hook ,h1 can be removed from the apparatus4 ,the drying space is closed from the upper part of the apparatus1 which contains no water by the cover ,j1 resting on a support ,k4 ,this rim is covered with a rubber gasket ,l1 by means of which the cover ,j can be fastened with a bayonet latch air-tight4 ,this fastening is shown at ,n4 ,being closed in this way the part of the cylindrical oven above the cover may be left entirely open4 ,instead of the rather elaborate method of closing the bath1 some simple and equally effective device might be used4 ,the cover ,j is best made with double metallic walls enclosing an asbestos packing4 ,illustration3 ,,figure #ae4 ,,wrampelmayer',s ,,oven4 ,it is evident that this oven could be used with an atmosphere of carbon dioxid or of air1 provided the gas for heating were derived from a separate source and the tube between ,e and ,f broken4 ,in a drying oven designed by the author1 the movable top is made with double walls and the space between is joined to the steam chamber by means of a flexible metallic tube1 thus entirely surrounding the drying space with steam4 #be4 ,the ,ulsch ,drying ,oven4--,a convenient drying oven is described by ,ulsch which varies from the ordinary form of a water-jacketed drying apparatus in having a series of drying tubes inserted in the water-steam space4 ,illustration3 ,,figure #af4 ,,ulsch ,,drying ,,oven4 ,the arrangement of the oven is shown in the accompanying figure4 ,the water space is filled only to about one-third of its height4 ,when the heat is applied the cock c is left open until the steam has driven out all the air4 ,it is then closed and the temperature of the bath is then regulated by the manometer e1 connected with the bath by d4 ,the bottom of the manometer cylinder contains enough mercury to always keep sealed the end of the manometer tube4 ,the rest of the space is filled with water4 ,at the top the manometer tube is expanded into a small bulb which serves as a gas regulator1 as shown in the figure4 ,the gas is admitted also by a small hole above the mercury in the bulb1 so that when the end of the gas inlet tube is sealed enough gas still passes through to keep the lamp burning4 ,with a mercury pressure of thirty centimeters the temperature of the bath will be about #aje4 ,the walls of the bath should be made strong enough to bear the pressure corresponding to this degree4 ,the drying can be accomplished either in the cubical drying box a or in the drying tubes made of thin copper and disposed as shown in the figure4 ,the natural draft is shown by the arrows4 ,the substance is held in boats placed in the tube as indicated4 ,the air in traversing the tube is brought almost to the temperature of the water-steam space in which the tube lies4 ,the natural current of hot air can easily be replaced by a stream of dry illuminating or other inert gas4 #bf4 ,drying ,viscous ,liquids4--,in the case of cane juices1 milk1 and similar substances1 the paper coil method may be used4#aa ,the manipulation is conducted as follows3 ,a strip of filtering paper from five to eight centimeters wide and forty centimeters in length1 is rolled into a loose coil and dried at the temperature of boiling water for two hours1 placed in a dry glass-stoppered weighing tube1 cooled in a desiccator and weighed4 ,the stoppered weighing tube prevents the absorption of hygroscopic moisture4 ,about three cubic centimeters of the viscous or semi-viscous liquid are placed in a flat dish covered by a plate of thin glass and weighed4 ,the coil is then placed on end in the dish1 and the greater part of the liquid is at once absorbed4 ,the proportions between the coil and the amount of liquid should be such that the coil will not be saturated more than two-thirds of its length4 ,it is then removed and placed dry end down in a steam-bath and dried two hours4 ,the dish1 covered by the same plate of glass1 is again weighed1 the loss in weight representing the quantity of liquid absorbed by the coil4 ,after drying for the time specified the coil is again placed in the hot weighing tube1 cooled and its weight ascertained4 ,the increase represents the solid matter in the sample taken4 ,this method has been somewhat modified by ,josse1 who directs that it be conducted as follows3#ab ,filter-paper is cut into strips from one to two centimeters wide and three meters long4 ,the strips are crimped so they will not lie too closely together and then wrapped into coils4 ,these coils can absorb about ten cubic centimeters of liquid4 ,one of them is placed in a flat dish about two centimeters high and seven in diameter1 and dried as described1 covered1 cooled and weighed4 ,there are next placed in the dish and weighed one or two grams of the massecuite1 molasses1 etc41 which are to be dried and the dish again weighed and the total weight of the matter added1 determined by deducting the weight of the dish and cover4 ,about eight cubic centimeters of water are added1 the material dissolved with gentle warming1 the coil placed in the dish1 and the whole dried for two hours4 ,the cover is then replaced and the whole cooled in a desiccator and weighed4 ,the increase in weight represents the dry matter in the sample taken4 ,the above method of solution of a viscous sample in order to divide it evenly for desiccation is based on the principle of the method first proposed by the author and ,broadbent for drying honeys and other viscous liquids4#ac ,in this process the sample of honey1 molasses1 or other viscous liquid is weighed in a flat dish1 dissolved in eighty per cent alcohol1 and then a weighed quantity of pure dry sand added1 sufficient to fill the dish three-quarters full4 ,the alcoholic solution of the viscous liquid is evenly distributed throughout the mass of sand by capillary attraction1 and thus easily and rapidly dried when placed on the bath4 ,pumice stone1 on account of its great porosity1 is also an excellent medium for the distribution of a viscous liquid in aiding the process of desiccation4 ,the method has been worked out in great detail in this laboratory by ,carr and ,sanborn1#ad and most excellent results obtained4 ,round aluminum dishes two centimeters high and from eight to ten centimeters in diameter are conveniently used for this process4 ,the pumice stone is dried and broken into fragments the size of a pea before use4 #bg4 ,general ,principles of ,drying ,samples4--,it would be a needless waste of space to go into further details of devices for desiccation4 ,a sufficient number has been given to fully illustrate all the principles involved4 ,in general1 it may be said that drying in the open air at a temperature not exceeding that of boiling water can be safely practiced with the majority of samples4 ,for instance1 we have found practically no change in this laboratory in the composition of cereals dried in the air and in an inert gas4 ,the desiccation should in all cases be accomplished as speedily as possible4 ,to this end the atmosphere in contact with the sample should be dry and kept in motion4 ,an oven surrounded by boiling water and steam is to be preferred to one heated by air4 ,constancy of temperature is quite as important as its degree and this steadiness is most easily secured by steam at atmospheric pressure4 ,where higher temperatures than #ajj are desired the steam must be under pressure1 or the boiling-point of the water may be raised by adding salt or other soluble matters4 ,a bath of paraffin or calcium chlorid may also be used or a sand or air-bath may be employed4 ,the analyst must not forget1 however1 that inorganic matters are prone to change at temperatures above #ajj1 even in an inert atmosphere1 and higher temperatures must be used with extreme caution4 ,drying in partial vacuum and in a slowly changing atmosphere may be practiced with all bodies and must be employed with some4 ,the simple form of apparatus already described will be found useful for this purpose4 ,at a vacuum of twenty inches or more1 even unstable organic agricultural products are in little danger of oxidation4 ,in the introduction of a dry gas1 therefore1 air will be found as a rule entirely satisfactory4 ,in the smaller form of vacuum apparatus described1 however1 there is no objection to the employment of hydrogen or of carbon dioxid4 ,the gas entering the apparatus should be dried by passing over calcium chlorid or by bubbling through sulfuric acid4 ,in this laboratory the vacuum is provided by an air-pump connected with a large exhaust cylinder4 ,this cylinder is connected by a system of pipes to all the working desks4 ,the chief objection to this system is the unsteadiness of the pressure4 ,when only a few are using the vacuum apparatus for filtering or other purposes the vacuum will stand at about twenty inches4 ,when no one is using it the vacuum will rise to twenty-eight or twenty-nine inches4 ,at other times1 when in general use1 it may fall to fifteen inches4 ,where a constant vacuum is desired for drying1 therefore1 it is advisable to connect the apparatus with a special aspirator which will give a pressure practically constant4 ,the dishes containing the sample should be low and flat1 exposing as large a surface as possible4 ,for viscous liquids it will be found advisable to previously fill the dishes with pumice stone or other inert absorbent material to increase the surface exposed4 ,the special methods of drying milk1 sirup1 honeys1 and like bodies1 will be described in the paragraphs devoted to these substances4 ,in drying agricultural products1 not only water but all other matters volatile at the temperature employed are expelled4 ,it is only necessary to conduct the products of volatilization through sulfuric acid to demonstrate the fact that organic bodies are given off4 ,in the case mentioned the sulfuric acid will be speedily changed to a brown and even black color by these bodies4 ,it is incontestable1 however1 that in most cases the essential oils and other volatile matters thus escaping are not large in quantity and could not appreciably affect the percentage composition of the sample4 ,in such cases the whole of the loss on drying is entered in the note book as water4 ,there are evidently many products1 however1 where a considerable percentage of the volatile products is not water4 ,the percentage of essential oils1 which have a lower boiling-point than water1 can be determined in a separate sample and this deducted from the total loss on drying will give the water4 ,simple as it seems1 the determination of water in agricultural products often presents peculiar difficulties and taxes to the utmost the patience and skill of the analyst4 ,having set forth the substantial principles of the process and indicated its more important methods1 there is left for the worker in the laboratory the choice of processes already described1 or1 in special cases1 the device of new ones and adaption of old ones to meet the requirements of necessity4 ,,incineration4 #bh4 ,determination of ,ash4--,the principle to be kept in view in the preparation of the ash of agricultural products is to conduct the incineration at as low a temperature as possible to secure a complete combustion4 ,the danger of too high a temperature is two-fold4 ,in the first place some of the mineral constituents constantly present in the ash1 notably1 some of the salts of potassium and sodium are volatile at high temperatures and thus escape detection4 ,in the second place1 some parts of the ash are rather easily fusible and in the melted state occlude particles of unburned organic matter1 and thus protect them from complete oxidation4 ,both of these dangers are avoided1 and an ash practically free of carbon obtained1 by conducting the combustion at the lowest possible temperature capable of securing the oxidation of the carbonaceous matter4 #bi4 ,products ,of ,combustion4--,the most important product of combustion1 from the present point of view1 is the mineral residue obtained4 ,the organic matter of the sample undergoes decomposition in various ways1 depending chiefly on its nature4 ,complex volatile compounds are formed first largely of an acid nature4 ,the residual carbon is oxidized to carbon dioxid and the hydrogen to water4 ,the relative proportions of these bodies formed1 in any given case1 depend on the conditions of combustion4 ,with a low temperature and a slow supply of oxygen1 the proportion of volatile organic compounds is increased4 ,at a high temperature1 and in a surplus of oxygen1 the proportions of water and carbon dioxid are greater4 ,at the present time1 however1 our attention is to be directed exclusively to the mineral residue2 the organic products of combustion belonging to the domain of organic chemistry4 ,as has already been intimated1 the ash of agricultural samples consists of the mineral matters derived from the tissues1 together with any accidental mineral impurities which may be present1 some unburned carbon1 and the sulfur1 phosphorus1 chlorin1 nitrogen1 etc41 existing previously in combination with the mineral bases4 ,the organic sulfur and phosphorus may also undergo complete or partial oxidation during incineration and be found in the ash4 ,unless special precautions be taken1 however1 a portion of the organic sulfur and phosphorus may escape as volatile compounds during the combustion4#ae ,the organic nitrogen is probably completely lost1 at most1 only traces of it being oxidized during the combustion in such a way as to combine with a mineral base4 ,the rare mineral elements that are taken up by plants will also be found in the ash4 ,here the analyst would look for copper1 boron1 zinc1 manganese1 and the other elements which1 when existing in the soil1 are apt to be found in the tissues of the plants1 not1 perhaps1 as organic or essential compounds1 but as concomitants of the other mineral foods absorbed by growing vegetation4 ,this fact is often of importance in toxicological and hygienic examinations of foods4 ,for instance1 traces of copper or of boron in the ash of a prescribed food would not be evidence of the use of copper or borax salts as preservatives unless it could be shown that the soil on which the food in question was grown was free of these bodies4 ,this fact manifestly applies only to those cases where mere traces of these rare bodies are in question4 ,the presence of considerable quantities of them1 enough to be inimical to health1 could only be attributed to artificial means4 #cj4 ,purpose and ,conduct of ,incineration4--,in burning a sample of an agricultural product the analyst may desire to secure either a large sample of ash for analytical purposes as already described or to determine the actual percentage of ash4 ,the first purpose is secured in many ways4 ,in the preparation of ash for manurial purposes1 for instance1 little care is exercised either to prevent volatilization of mineral matters or to avoid the occurrence of a considerable quantity of carbon in the sample4 ,with this operation we have1 at present1 nothing whatever to do4 ,in preparing a sample of ash for chemical analysis it is important1 where a sufficient quantity of the sample can be obtained1 to use as large a quantity of it as convenient4 ,while it is true that very good results may be secured on very small samples1 it is always advisable to have a good supply of the material at hand4 ,since the materials burned have only from one to three per cent of ash1 a kilogram of them will supply only from ten to thirty grams4 ,to supply all needful quantities of material and replace the losses due to accident1 whenever possible at least twenty grams of the ash should be prepared4 ,the combustion can be carried on in platinum dishes with all bodies free of metallic oxids capable of injuring the platinum4 ,otherwise porcelain or clay dishes may be employed4 ,as a rule the combustion is best conducted in a muffle at a low red heat4 ,with substances very rich in fusible ash1 as for instance the cereals1 it is advisable to first char them1 extract the greater part of the ash with water1 and afterwards burn the residual carbon4 ,the aqueous extract can then be added to the residue of combustion and evaporated to dryness at the temperature of boiling water4 ,during the combustion the contents of the dish should not be disturbed until the carbon is as completely burned out as possible4 ,the naturally porous condition in which the mass is left during the burning is best suited to the entire oxidation of the carbon4 ,at the end however1 it may become necessary to bring the superficial particles of unburned carbon into direct contact with the bottom of the dish by stirring its contents4 ,in most instances very good results may be obtained by burning the ash in an open dish without the aid of a muffle4 ,in this case a lamp should be used with diffuse flame covering as evenly as possible the bottom of the dish and thus securing a uniform temperature4 ,the carbon1 when once in active combustion1 will as a rule be consumed1 and an ash reasonably pure be obtained4 ,the second purpose held in view by the analyst is to determine the actual content of ash in a sample4 ,for this purpose only a small quantity of the material should be used1 generally from two to ten grams4 ,the combustion should be conducted in flat-bottomed1 shallow dishes1 and at a low temperature4 ,in many cases the residue1 after determining the moisture1 can be at once subjected to incineration1 and thus an important saving of time be secured4 ,a muffle1 with gentle draft1 will be found most useful for securing a white ash4 ,the term1 white ash1 is sometimes a deceptive one4 ,in samples containing iron or manganese1 the ash may be practically free of carbon and yet be highly colored4 ,the point at which the combustion is to be considered as finished therefore should be at the time the carbon has disappeared rather than when no coloration exists4 ,in general the methods of incineration are the same for all substances1 but some cases may arise in which special processes must be employed4 ,some analysts prefer to saturate the substance before incineration with sulfuric acid1 securing thus a sulfated ash4 ,this is practiced especially with molasses4 ,in such cases the ash obtained is free of carbon dioxid and roughly the difference in weight is compensated for by deducting one-tenth of the weight of the ash when comparison is to be made with ordinary carbonated ash4 ,naturally this process could not be used when sulfuric acid is to be determined in the product4 ,illustration3 ,,figure #ag4 ,,courtoune ,,muffle4 #ca4 ,german ,ash ,method4--,the method pursued at the ,halle ,station for securing the percentage of ash in a sample is as follows3#af ,five grams of the air-dried sample are incinerated in a platinum dish and the ash ignited until it has assumed a white1 or at least a bright gray tint4 ,as soon as combustible gases are emitted at the beginning of the incineration they are ignited and allowed to burn as long as possible4 ,it is advisable to hasten the oxidation by stirring the mass with a piece of platinum wire4 ,if the ash should become agglomerated1 as sometimes happens with rich food materials1 it must be separated by attrition4 ,the ash1 when cooled on a desiccator1 is to be weighed4 ,when great exactness is required1 it is advised1 as set forth in a former paragraph1 to first carbonize the mass and then extract the soluble ash with hot water before completing the oxidation4 ,when the latter is complete and the dish cooled the aqueous extract is added1 evaporated to dryness and the incineration completed4 #cb4 ,courtonne's ,muffle4--,the ordinary arrangement of a muffle1 as in assaying1 may be conveniently used in incineration4 ,a special muffle arrangement has been prepared by ,courtonne which not only permits of the burning of a large number of samples at once1 but also effects a considerable saving in gas4 ,the muffle as shown in ,fig4 #ag1 is made in two stages1 and the floor projects in front of the furnace1 forming a convenient hearth4 ,the incineration is commenced on the upper stage1 where the temperature is low1 and finished on the lower one at a higher heat4 ,the furnace is so arranged as to permit the flame of the burning gas to entirely surround the muffle4 ,the draft and temperature within the muffle are controlled by the fire-clay door shown resting on the table4 ,,treatment ,,with ,,solvents4 #cc4 ,object ,of ,treatment4--,the next step1 in the analytical work1 after sampling1 drying1 and incinerating1 is the treatment of the sample with solvents4 ,the object of this work is to separate the material under examination into distinct classes of bodies distinguished from each other by their solubilities4 ,it is not the purpose of this section to describe the various bodies which may be separated in this way1 especially from vegetable products4 ,for this description the reader may consult the standard works on plant analysis4#ag ,the chief object of a strictly agricultural examination of a field or garden product is to determine its food value4 ,this purpose can be accomplished without entering into a minute separation of nearly allied bodies4 ,for example1 in the case of carbohydrates it will be sufficient as a rule1 to separate them into four classes4 ,in the first class will be found those soluble in water as the ordinary sugars4 ,in the second group will be found those which1 while not easily soluble in water1 are readily rendered so by treatment with certain ferments or by hydrolysis with an acid4 ,the starches are types of this class4 ,in the third place are found those bodies which resist the usual processes of hydrolysis either with an acid or alkali1 and therefore remain in the residue as fiber4 ,cellulose is a type of these bodies4 ,in the fourth class are included those bodies which on hydrolysis with an acid yield furfurol on distillation1 and therefore belong to the type containing five atoms of carbon or some multiple thereof in their molecule4 ,for ordinary agricultural purpose the separation is not even as complete as is represented above4 ,what is true of the carbohydrates applies equally well to the fats and to other groups4 ,especially in the analysis of cereals and of cattle foods1 the treatment with solvents is confined to the use in successive order of ether or petroleum1 alcohol1 dilute acids1 and alkalies1 the latter at a boiling temperature4 ,the general method of treatment with these solvents will be the subject of the following paragraphs4 #cd4 ,extraction of the ,fats and ,oils4--,two solvents are in general use for the extraction of fats and oils2 viz41 ethylic ether and a light petroleum4 ,the former is the more common reagent4 ,before use it should be made as pure as possible by washing first with water1 afterwards removing the water by lime or calcium chlorid1 and then completing the drying by treatment with metallic sodium4 ,the petroleum spirit used should be purified by several fractional distillations until it has nearly a constant boiling-point of from #de to #ej4 ,the detailed methods of preparing these reagents will be given in another place4 ,for rigid scientific determinations the petroleum is to be preferred to the ether4 ,it is equally as good a solvent for fats and oils and is almost inert in respect to other vegetable constituents4 ,ether1 on the other hand1 dissolves chlorophyll and its partial oxidation products1 resins1 alkaloids and the like4 ,the extract obtained by ether is therefore less likely to be a pure fat than that secured by petroleum4 ,for purposes of comparison1 however1 the ether should be employed1 inasmuch as it has been used almost exclusively in analytical operations in the past4 #ce4 ,methods ,of ,extraction4--,the simplest method for accomplishing the extraction of fat from a sample consists in treating it with successive portions of the solvent in an open dish or a closed flask4 ,this process is actually employed in some analytical operations1 as1 for instance1 in the determination of fat in milk4 ,experience has shown1 however1 that a portion of the substance soluble1 for instance1 in ether1 passes very slowly into solution1 so that a treatment such as that just described would have to be long continued to secure maximum results4 ,the quantity of solvent required would thus become very large and in the case of ether would entail a great expense4 ,for the greater number of analytical operations1 therefore1 some device is employed for using the same solvent continually4 ,the methods of extraction therefore fall into two general classes2 viz41 extraction by digestion and extraction by percolation4 ,this classification holds good also for other solvents besides ether and petroleum4 ,in general1 the principles and practice of extraction described for ether may serve equally well for alcohol1 acetone and other common solvents4 #cf4 ,extraction by ,digestion4--,in the use of ether or petroleum the sample is covered with an excess of the solvent and allowed to remain for some time in contact therewith4 ,the soluble portions of the sample diffuse into the reagent4 ,the speed of diffusion is promoted by stirring the mixtures4 ,the operation may be conducted in an open dish or a flask4 ,inasmuch as the residue is1 as a rule1 to be dried and weighed1 an open dish is to be preferred4 ,to avoid loss of reagent and to prevent filling a working room with very dangerous gases1 the temperature of digestion should be kept below the boiling-point of the solvent4 ,the greater part of the soluble matter will be extracted with three or four successive applications of the reagent1 but1 as intimated above1 the last portions of the soluble material are extracted with difficulty by this process4 ,in pouring off the solvent care must be exercised to avoid loss of particles of the sample suspended therein4 ,to this end it is best to pour the solvent through a filter4 ,for the extraction of large quantities of material for the purpose of securing the extract for future examination1 or simply to remove it1 the digestion process is usually employed4 ,this excess of solvent required is easily recovered by subsequent distillation and used again4 ,the method is rarely used for the quantitive estimation of the extract1 the process of continuous percolation being more convenient and more exact4 #cg4 ,extraction by ,percolation4--,in this method the solvent employed is poured on the top of the material to be extracted and allowed to pass through it usually by gravitation alone1 sometimes with the help of a filter-pump4 ,the principle of the process is essentially that of washing precipitates4 ,two distinct forms of apparatus are in use for this process4 ,in the first kind the solvent is poured over the material and after percolation is secured by distillation in another apparatus4 ,in the second kind the solvent is secured after percolation in a flask where it is at once subjected to distillation4 ,the vapors of the solvent are conducted by appropriate means to a condenser placed above the sample4 ,after condensation the solvent is returned to the upper part of the sample4 ,the percolation thus becomes continuous and a very small quantity of the solvent may thus be made to extract a comparatively large amount of material4 ,this process is particularly applicable to the quantitive determination of the extract4 ,after distillation and drying the latter may be weighed in the flask in which it was received or the sample may be dried and weighed in the vessel in which it is held both before and after extraction4 ,one great advantage of the continuous extraction method lies in the fact that when it is once properly started it goes on without further attention from the analyst save an occasional examination of the flow of water through the condenser and of the rate of the distillation4 ,for this reason the process may be continued for many hours without any notable loss of time4 ,the vapor of the solvent in passing to the condenser may pass through a tube out of contact with the material to be extracted or it may pass directly around the tube holding the sample4 ,in the former case the advantage is secured of conducting the extraction at a higher temperature1 but there is danger of boiling the solvent in contact with the material and thus permitting the loss of a portion of the sample4 #ch4 ,apparatus ,used for ,extractions4--,for extraction by digestion1 as has already been said1 an open dish may be used4 ,when large quantities of material are under treatment1 heavy flasks1 holding from five to ten liters1 will be found convenient4 ,in these cases a condenser can be attached to the flask and the extraction conducted at the boiling temperature of the solvent4 ,during the process of extraction it is advisable to shake the flask frequently4 ,by proceeding in this way the greater part of the solvent matter will be removed after three or four successive treatments4 ,in extraction by percolation various forms of apparatus are employed4 ,the ordinary percolators of the manufacturing pharmacist may be used for the larger operations1 while the more elaborate forms of continuous extractors will be found most convenient for quantitive work4 ,in each case the analyst must choose that process and form of apparatus best suited to the purpose in view4 ,in the next paragraphs will be described some of the more common forms of apparatus in use4 #ci4 ,knorr's ,extraction ,apparatus4--,the apparatus which has been chiefly used in this laboratory for the past few years is shown in the accompanying figure4#ah ,the principle of the construction of the apparatus lies in the complete suppression of stoppers and in sealing the only joint of the device with mercury4 ,the construction and operation of the apparatus will be understood by a brief description of its parts4 ,a is the flask containing the solvent1 ,w a steam bath made by cutting off the top of a bottle1 inverting it and conducting the steam into one of the tubes shown in the stopper while the condensed water runs out of the other4 ,the top of the bath is covered with a number of concentric copper rings1 so that the opening may be made of any desirable size4 ,b represents the condenser1 which is a long glass tube on which a number of bulbs has been blown1 and which is attached to the hood for holding the material to be extracted1 as represented at ,b1 making a solid glass union4 ,before joining the tube at ,b the rubber stopper which is to hold it into the outside condenser of ,b is slipped on1 or the rubber stopper may be cut into its center and slipped over the tube after the union is made4 ,in case alcohol is to be used for the solvent1 requiring a higher temperature1 the flask holding the solvent is placed entirely within the steam-bath1 as represented at ,a4 ,illustration3 ,,figure #ah4 ,,knorr',s ,,extraction ,,apparatus4 ,illustration3 ,,figure #ai4 ,,extraction ,,flask4 ,illustration3 ,,figure #bj4 ,,extraction ,,tube4 ,illustration3 ,,figure #ba4 ,,extraction ,,siphon ,,tube4 ,a more detailed description of the different parts of the apparatus can be seen by consulting ,figs4 #ai1 #bj1 and #ba4 ,in ,a1 ,fig4 #ai1 is represented a section of the flask which holds the solvent1 showing how the sides of the hood containing the matters to be extracted pass over the neck of the flask1 and showing at ,s a small siphon inserted in the space between the neck of the flask and the walls of the hood for the purpose of removing any solvent that may accumulate in this space4 ,a view of the flask itself is shown at ,a4 ,it is made by taking an ordinary flask1 softening it about the neck and pressing the neck in so as to form a cup1 as indicated at ,a1 to hold the mercury which seals the union of the flask with the condenser4 ,the flask is held in position by passing a rubber band below it1 which is attached to two glass nipples1 b1 blown onto the containing vessel1 as shown in ,fig4 #ah4 ,the material to be extracted may be contained in an ordinary tube1 as shown in ,fig4 #bj1 which may be made from a test tube drawn out1 as indicated in the figure1 having a perforated platinum disk sealed in at ,d4 ,the containing tube rests upon the edges of the flask containing the solvent by means of nipples shown at t4 ,if a siphon tube is to be used1 one of the most convenient forms is shown in ,fig4 #ba1 in which the siphon lies entirely within the extracting tube1 thus being protected from breakage4 ,by means of this apparatus the extractions can be carried on with a very small quantity of solvent1 there being scarcely any leakage1 even with the most volatile solvents1 such as ether and petroleum4 ,the apparatus is always ready for use1 no corks are to be extracted1 and no ground glass joints to be fitted4 #dj4 ,soxhlet's ,extraction ,apparatus4--,a form of continuous extraction apparatus has been proposed by ,soxhlet which permits the passage of the vapors of the solvent into the condenser by a separate tube and the return of the condensed solvent after having stood in contact with the sample1 to the evaporating flask by a siphon4 ,the advantage of this process lies in freeing the sample entirely from the rise of temperature due to contact with the vapors of the solvent1 and in the second place in the complete saturation of the sample with the solvent before siphoning4 ,the sample is conveniently held in a cylinder of extracted filter-paper open above and closed below4 ,this is placed in the large tube between the evaporating flask and the condenser4 ,the sample should not fill the paper holder1 and if disposed to float in the solvent1 should be held down with a plug of asbestos fiber or of glass wool4 ,the extract may be transferred1 by dissolving in the solvent1 from the flask to a drying dish1 or it may be dried and weighed in the flask where first received4 ,illustration3 ,,figure #bb4 ,,soxhlet ,,extraction ,,apparatus4 ,there are many forms of apparatus of this kind1 one of which is shown in ,fig4 #bb1 but a more extended description of them is not necessary4 ,the disadvantages of this process as compared with ,knorr's1 are quite apparent4 ,the connections with the evaporating flask and condenser are made with cork stoppers1 which must be previously thoroughly extracted with ether and alcohol4 ,these corks soon become dry and hard and difficult to use4 ,the joints are likely to leak1 and grave dangers of explosion arise from the vapors of the solvents escaping into the working room4 ,moreover1 it is an advantage to have the sample warmed by the vapors of the solvent during the progress of the extraction1 provided the liquid in direct contact with the sample does not boil with sufficient vigor to cause loss4 ,the use of extraction apparatus with ground glass joints is also unsatisfactory4 ,by reason of unequal expansion and contraction these joints often are not tight4 ,they are also liable to break and thus bring danger and loss of time4 #da4 ,compact ,extraction ,apparatus4--,in order to bring the extraction apparatus into a more compact form1 the following described device has been successfully used in this laboratory4#ai ,the condenser employed is made of metal and is found entirely within the tube holding the solvent4 ,this form of condenser is shown in ,fig4 #bc1 in which the tube ,e serves to introduce the cold water to the bottom of the condensing device4 ,the tube ,d serves to carry away the waste water4 ,the tube ,f serves for the introduction of the solvent by means of a small funnel4 ,when the solvent is introduced and has boiled for a short time1 the tube ,f should be closed4 ,in each of the double conical sections of the condenser a circular disk ,b is found1 which causes the water flowing from ,a upward to pass against the metallic surfaces of the condenser4 ,a section of the double conical condenser is shown in the upper right hand corner4 ,it is provided with two small hooks hh1 soldered on the lower surface1 by means of which the crucible ,g can be hung with a platinum wire4 ,the condenser is best made smooth and circular in form4 ,the crucible ,g1 which holds the material to be extracted1 can be made of platinum1 but for sake of economy also of porcelain4 ,the bottom of the porcelain crucible is left open excepting a small shelf1 as indicated1 which supports a perforated disk of platinum on which an asbestos film is placed4 ,illustration3 ,,figure #bc4 ,,compact ,,condensing ,,apparatus4 ,the whole apparatus is of such size as to be easily contained in the large test-tube ,t4 ,the mouth of the test-tube is ground so as to fit as smoothly as possible to the ground-brass plate of the metallic condenser ,p4 ,in case it is desired to weigh the extract it may be done directly by weighing it in the test-tube ,t after drying in the usual way at the end of the extraction2 or a glass flask ,h1 made to fit freely into the test-tube1 may be used1 in which case a little mercury is poured into the bottom of the tube to seal the space between ,h and ,t4 ,to prevent spirting of the substance in ,h1 or projecting any of the extracted material without or against the bottom of the crucible ,g1 the funnel represented by the dotted lines in the right hand section may be used4 ,heat may be applied to the test-tube either by hot water1 or steam1 or by a bunsen1 which permits of the flame being turned down to minimum proportions without danger of burning back4 ,when the test-tube alone is used it is advisable to first put into it some fragments of pumice stone1 particles of platinum foil1 or a spoonful of shot1 to prevent bumping of the liquid when the lamp is used as the source of heat4 ,any air which the apparatus contains is pushed out through ,f when the boiling begins1 the tube ,f not being closed until the vapor of the liquid has reached its maximum height4 ,with cold water in the condenser the vapor of ether very rarely reaches above the lower compartment and the vapor of alcohol rarely above the second4 ,when the plate ,p is accurately turned so as to fit the ground surface of the mouth of ,t1 it is found that ten cubic centimeters of anhydrous ether or alcohol are sufficient to make a complete extraction1 and there is not much loss of solvent in six hours4 ,the thickness of the asbestos film in ,g1 or its fineness1 is so adjusted as to prevent too rapid filtration so that the solvent may just cover the material to be extracted1 or1 after the material is placed in a crucible1 a plug of extracted glass wool may be placed above it for the purpose of distributing the solvent evenly over the surface of the material to be extracted and of preventing the escape of fine particles4 ,illustration3 ,,figure #bd4 ,,improved ,,compact ,,extraction ,,apparatus4 ,in very warm weather the apparatus may be arranged as shown in figure #bd4 ,the bath for holding the extraction tubes is made in two parts1 ,k and ,k4 ,the bath ,k has a false bottom shown in the dotted line ,o1 perforated to receive the ends of the extraction tubes and which holds them in place and prevents them from touching the true bottom1 where they might be unequally heated by the lamp4 ,the upper bath ,k has a perforated bottom1 partly closed with rubber-cloth diaphragms ,g ,n ,h4 ,the extraction tubes passing through this bath1 water-tight1 permit broken ice or ice-water to be held about their tops1 and thus secure a complete condensation of the vapors of the solvent which in warm weather might escape the metal condenser4 ,in practice care must be taken to avoid enveloping too much of the upper part of the extraction tube with the ice-water1 otherwise the vapors of the solvent will be chiefly condensed on the sides of the extraction tube and will not be returned through the sample4 ,it is not often that the upper bath is needed1 and then only with ether1 never with alcohol4 ,this apparatus has proved especially useful with alcohol1 using1 as suggested1 glycerol in the bath4 ,the details of its further construction and arrangement are shown in the figure4 ,the extraction tubes are most conveniently arranged in a battery of four1 one current of cold water passing in at ,a and out at ,b1 serving for all4 ,the bath is supported on legs long enough to allow the lamp plenty of room4 ,the details of the condenser ,m are shown in ,b1 ,a1 ,t1 ,f1 and ,l4 ,instead of a gooch ,l for holding the sample a glass tube ,r1 with a perforated platinum disk ,q1 may be used4 ,the water line in the bath is shown by ,w4 ,this apparatus may be made very cheaply and without greatly impairing its efficiency by using a plain concentric condenser and leaving off the upper bath ,k4 #db4 ,solvents ,employed4--,it has already been intimated that the chief solvents employed in the extraction of agricultural samples are ether or petroleum and aqueous alcohol4 ,the ether used should be free of alcohol and water1 the petroleum should be subjected to fractional distillation to free it of the parts of very high and very low boiling points1 and the alcohol as a rule should contain about twenty per cent of water4 ,there are many instances1 however1 where other solvents should be used4 ,the use of aqueous alcohol is sometimes preceded by that of alcohol of greater strength or practically free of water4 ,for the extraction of soluble carbohydrates 7sugars7 cold or tepid water is employed1 the temperature of which is not allowed to rise high enough to act upon starch granules4 ,for the solution of the starch itself an acid solvent is used at a boiling temperature1 whereby the starch molecules undergo hydrolysis and form dextrin or soluble sugars 7maltose1 dextrose74 ,by this process also the carbohydrates1 whose molecules contain five1 or some multiple thereof1 atoms of carbon form soluble sugars of which xylose and arabinose are types4 ,the solvent action of acids followed by treatment with dilute alkalies at a boiling temperature1 completes practically the solution of all the carbohydrate bodies1 save cellulose and nearly related compounds4 ,the starch carbohydrates are further dissolved by the action of certain ferments such as diastase4 ,dilute solutions of mineral salts exert a specific solvent action on certain nitrogenous compounds and serve to help separate the albuminoid bodies into definite groups4 ,under the proper headings the uses of these principal solvents will be described1 but a complete discussion of their action1 especially on samples of a vegetable origin1 should be looked for in works on plant analysis4#bj ,the application of acids and alkalies for the extraction of carbohydrates1 insoluble in water and alcohol1 will be described1 in the paragraphs devoted to the analysis of fodders and cereals4 ,the extraction of these matters1 made soluble by ferments1 will be discussed in the pages devoted to starch and artificial digestion4 ,it is thus seen that the general preliminary treatment of a sample preparatory to specific methods of examination is confined to drying1 extraction with ether and alcohol1 and incineration4 #dc4 ,recovery of the ,solvent4--,in using such solvents as ether1 chloroform1 and others of high value1 it is desirable often to recover the solvent4 ,various forms of apparatus are employed for this purpose1 arranged in such a way as both to secure the solvent and to leave the residue in an accessible condition1 or in a form suited to weighing in quantitive work4 ,when the extractions are made according to the improved method of ,knorr1 the flask containing the extract may be at once connected with the apparatus shown in figure #be4ba ,a represents the flask containing the solvent to be recovered1 ,w the steam-bath1 ,b the condenser sealed by mercury1 ,m and ,r the flask receiving the products of condensation4 ,it will be found economical to save ether1 alcohol1 and chloroform even when only a few cubic centimeters remain after the extraction is complete4 ,in the figure the neck of the flask ,a is represented as narrower than it really is4 ,the open end of the connecting tube1 which is sealed on ,a by mercury1 should be the same size as the tube connecting with the condenser in the extraction apparatus4 ,illustration3 ,,figure #be4--,,knorr',s ,,apparatus ,,for ,,receiving ,,solvents4 ,illustration3 ,,figure #bf4 ,,apparatus ,,for ,,recovering ,,solvents ,,from ,,open ,,dishes4 ,it often happens that materials which are dissolved by the ordinary solvents in use are to be collected in open dishes in order that their properties may be studied4 ,at the same time large quantities of solvents must be used1 and it is desirable to have some method of recovering them4 ,the device shown in ,fig4 #bf has been found to work excellently well for this purpose4#bb ,it consists of a steam-bath1 ,w1 and a bottle1 ,b1 with the bottom cut off1 resting on an iron dish1 ,p1 containing a small quantity of mercury1 enough to seal the bottom of the bottle4 ,the dish containing the solvent is placed on the mercury1 and the bottle placed down over it1 forming a tight joint4 ,on the application of steam the solvent escapes into the condenser1 ,c1 and is collected as a liquid in the flask ,a4 ,in very volatile solvents the flask ,a may be surrounded with ice1 or ice-cold water passed through the condenser4 ,when an additional quantity of the solvent is to be added to the dish for the purpose of evaporating it is poured into the funnel ,f1 and the stopcock ,h opened1 which allows the material to run into the dish in ,b without removing the bottle4 ,in this way many liters of the solvent may be evaporated in any one dish1 and the total amount of extract obtained together4 ,at the last the bottle ,b is removed1 and the extract which is found in the dish is ready for further operations4 ,,authorities ,,cited ,,in ,,part ,,first4 #a ,sidersky3 ,trait d',analyse des ,matires ,sucres1 p4 #caa4 #b ,die ,agricultur-,chemische ,versuchs-,station1 ,halle a_/,s41 ,s4 #cd4 7,read ,dreef instead of ,dree47 #c ,report of ,commissioner of ,fish and ,fisheries1 #ahhh1 p4 #fhf4 #d ,vid4 op4 cit4 #b1 p4 #ad4 #e ,journal of the ,american ,chemical ,society1 ,vol4 #ae1 p4 #hc4 #f ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #bh1 p4 #aja4 #g ,not yet described in any publication4 ,presented at #abth annual meeting of the ,association of ,agricultural ,chemists1 ,aug4 #gth1 #ahie4 #h ,vid4 op4 cit4 #f1 p4 #ajj4 #i ,cornell ,university ,agricultural ,experiment ,station1 ,bulletin #ab4 #aj 7bis4 p4 #bh74 ,vid4 op4 cit4 #b1 p4 #ae4 #aa ,bulletin ,no4 #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,part ,first pp4 #he-f4 #ab ,bulletin de #a' ,association des ,chimistes de ,sucrerie1 #ahic1 p4 #fef4 #ac ,chemical ,news1 ,vol4 #eb1 p4 #bhj4 #ad ,presented to #abth ,annual ,convention of the ,association of ,official ,agricultural ,chemists1 ,sept4 #gth1 #ahie4 #ae ,vid4 ,volume ,first1 p4 #daa4 #af ,vid4 op4 cit4 #b1 p4 #ag4 #ag ,dragendorff1 ,plant ,analysis4 #ah ,vid4 op4 cit4 #f1 p4 #if4 #ai ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #g1 p4 #fe1 and ,journal of the ,american ,chemical ,society1 ,march #ahic4 #bj ,vid4 op4 cit4 #af4 #ba ,vid4 op4 cit4 #f1 p4 #ii4 #bb ,vid4 op4 cit4 #f1 p4 #ajc4 ,,part ,,second4 ,,sugars ,,and ,,starches4 #dd4 ,introduction4--,carbohydrates1 of which sugars and starches are the chief representatives1 form the great mass of the results of vegetable metabolism4 ,the first functions of the chlorophyll cells of the young plant are the condensation of carbon dioxid and water4 ,the simplest form of the condensation is formaldehyd1 ,,ch,o4 ,there is no convincing evidence1 however1 that this is the product resulting from the functional activity of the chlorophyll cells4 ,the first evidence of the condensation is found in more complex molecules2 viz41 those having six atoms of carbon4 ,it is not the purpose of this work to discuss the physiology of this process1 but the interested student can easily find access to the literature of the subject4#bc ,when a sample of a vegetable nature reaches the analyst he finds by far the largest part of its substance composed of these products of condensation of the carbon dioxid and water4 ,the sugars1 starches1 pentosans1 lignoses1 and celluloses all have this common origin4 ,of many air-dried plants these bodies form more than eighty per cent4 ,in green plants the sugars exist chiefly in the sap4 ,in plants cut green and quickly dried by artificial means the sugars are found in a solid state4 ,they also exist in the solid state naturally in certain sacchariferous seeds4 ,many sugar-bearing plants when allowed to dry spontaneously lose all or the greater part of their sugar by fermentation4 ,this is true of sugar cane1 sorghum1 maize stalks1 and the like4 ,the starches are found deposited chiefly in tubers1 roots or seeds4 ,in the potato the starch is in the tuber1 in cassava the tuber holding the starch is also a root1 in maize1 rice and other cereals the starch is in the seeds4 ,the wood-fibers2 viz41 pentosans1 lignose1 cellulose1 etc41 form the framework and support of the plant structure4 ,of all these carbohydrate bodies the most important as foods are the sugars and starches1 but a certain degree of digestibility cannot be denied to other carbohydrate bodies with the possible exception of pure cellulose4 ,in the following paragraphs the general principles of determining the sugars and starches will be given and afterwards the special processes of extracting these bodies from vegetable substances preparatory to quantitive determination4 #de4 ,nomenclature4--,in speaking of sugars it has been thought best to retain for the present the old nomenclature in order to avoid confusion4 ,the terms dextrose1 levulose1 sucrose1 etc41 will therefore be given their commonly accepted significations4 ,a more scientific nomenclature has recently been proposed by ,fischer1 in which glucose is used as the equivalent of dextrose and fructose as the proper name for levulose4 ,all sugars are further classified by ,fischer into groups according to the number of carbon atoms found in the molecule4 ,we have thus trioses1 tetroses1 pentoses1 hexoses1 etc4 ,such a sugar as sucrose is called hexobiose by reason of the fact that it appears to be formed of two molecules of hexose sugars4 ,for a similar reason raffinose would belong to the hexotriose group4#bd ,again1 the two great classes of sugars as determined by the structure of the molecule are termed aldoses and ketoses according to their relationship to the aldehyd or ketone bodies4 ,since sugars may be optically twinned1 that is composed of equal molecules of right and left-handed polarizing matter it may happen that apparently the same body may deflect the plane of polarization to the right1 to the left1 or show perfect neutrality4 ,natural sugars1 as a rule1 are optically active1 but synthetic sugars being optically twinned are apt to be neutral to polarized light4 ,to designate the original optical properties of the body therefore the symbols d1 l1 and i1 meaning dextrogyratory1 levogyratory1 and inactive1 respectively1 are prefixed to the name4 ,thus we may have d1 l1 or i glucose1 d1 l1 or i fructose1 and so on4 ,the sugars that are of interest here belong altogether to the pentose and hexose groups2 viz41 ,c,h,o and ,c,h,o1 respectively4 ,of the hexobioses1 sucrose1 maltose1 and lactose are the most important1 and of the hexotrioses1 raffinose4 ,in this manual1 unless otherwise stated1 the term dextrose corresponds to d glucose1 and levulose to d fructose4 ,in this connection1 however1 it should be noted that the levulose of nature1 or that which is formed by the hydrolysis of inulin or sucrose is not identical in its optical properties with the l fructose of ,fischer4 #df4 ,preparation of ,pure ,sugar4--,in using the polariscope or in testing solutions for the chemical analysis of samples1 the analyst will be required to keep always on hand some pure sugar4 ,several methods of preparing pure sugar have been proposed4 ,the finest granulated sugar of commerce is almost pure4 ,in securing samples for examination those should be selected which have had a minimum treatment with bluing in manufacture4 ,the best quality of granulated sugar when pulverized1 washed with ninety-five per cent and then with absolute alcohol and dried over sulfuric acid at a temperature not exceeding #ej will be found nearly pure4 ,such a sugar will1 as a rule1 not contain more than one-tenth per cent of impurities1 and can be safely used for all analytical purposes4 ,it is assumed in the above that the granulated sugar is made from sugar cane4 ,granulated beet sugars may contain raffinose and so may show a polarization in excess of #ajj4 ,this sugar may be purified by dissolving seventy parts by weight in thirty parts of water4 ,the sugar is precipitated by adding slowly an equal volume of ninety-six per cent alcohol with constant stirring1 the temperature of the mixture being kept at #fj4 ,while still warm the supernatant liquor is decanted and the precipitated sugar washed by decantation several times with strong warm alcohol4 ,the sugar1 on a filter1 is finally washed with absolute alcohol and dried in a thin layer over sulfuric acid at from #ce to #dj4 ,by this process any raffinose which the sugar may have contained is completely removed by the warm alcohol4 ,since beet sugar is gradually coming into use in this country it is safer to follow the above method with all samples4#be ,in former times it was customary to prepare pure sugar from the whitest crystals of rock candy4 ,these crystals are powdered1 dissolved in water1 filtered1 precipitated with alcohol1 washed and dried in the manner described above4 #dg4 ,classification of ,methods4--,in the quantitive determination of pure sugar the various processes employed may all be grouped into three classes4 ,in the first class are included all those which deduce the percentage of sugar present from the specific gravity of its aqueous solution4 ,the accuracy of this process depends on the purity of the material1 the proper control of the temperature1 and the reliability of the instruments employed4 ,the results are obtained either directly from the scale of the instruments employed or are calculated from the arbitrary or specific gravity numbers observed4 ,it is evident that any impurity in the solution would serve to introduce an error of a magnitude depending on the percentage of impurity and the deviation of the density from that of sugar4 ,the different classes of sugars1 having different densities in solution1 give also different readings on the instruments employed4 ,it is evident1 therefore1 that a series of tables of percentages corresponding to the specific gravities of the solutions of different sugars would be necessary for exact work4 ,practically1 however1 the sugar which is most abundant1 viz41 sucrose1 may be taken as a representative of the others and for rapid control work the densimetric method is highly useful4 ,in the second class of methods are grouped all those processes which depend upon the property of sugar solutions to rotate the plane of polarized light4 ,natural sugars all have this property and if their solutions be found neutral to polarized light it is because they contain sugars of opposite polarizing powers of equal intensity4 ,some sugars turn the polarized plane to the right and others to the left1 and the degree of rotation in each case depends1 at equal temperatures and densities of the solutions1 on the percentages of sugars present4 ,in order that the optical examination of a sugar may give correct results the solution must be of a known density and free of other bodies capable of affecting the plane of polarized light4 ,in the following paragraphs an attempt will be made to give in sufficient detail the methods of practice of these different processes in so far as they are of interest to the agricultural analyst4 ,the number of variations1 however1 in these processes is so great as to make the attempt to fully discuss them here impracticable4 ,the searcher for additional details should consult the standard works on sugar analysis4#bf ,in the third class of methods are included those which are of a chemical nature based either on the reducing power which sugar solutions exercise on certain metallic salts1 upon the formation of certain crystalline and insoluble compounds with other bodies or upon fermentation4 ,under proper conditions solutions of sugar reduce solutions of certain metallic salts1 throwing out either the metal itself or a low oxid thereof4 ,in alkaline solutions of mercury and copper1 sugars exercise a reducing action1 throwing out in the one case metallic mercury and in the other cuprous oxid4 ,with phenylhydrazin1 sugars form definite crystalline compounds1 quite insoluble1 which can be collected1 dried and weighed4 ,there is a large number of other chemical reactions with sugars such as their union with the earthy bases1 color reactions with alkalies1 oxidation products with acids1 and so on1 which are of great use qualitively and in technological processes1 but these are of little value in quantitive determinations4 ,,the ,,determination ,,of ,,the ,,percentage ,,of ,,sugar ,,by ,,the ,,density ,,of ,,its ,,solution4 #dh4 ,principles of the ,method4--,this method of analysis is applied almost exclusively to the examination of one kind of sugar1 viz41 the common sugar of commerce4 ,this sugar is derived chiefly from sugar cane and sugar beets and is known chemically as sucrose or saccharose4 ,the method is accurate only when applied to solutions of pure sucrose which contain no other bodies4 ,it is evident however1 that other bodies in solution can be determined by the same process1 so that the principle of the method is broadly applicable to the analyses of any body whatever in a liquid state or in solution4 ,gases1 liquids and solids1 in solution1 can all be determined by densimetric methods4 ,broadly stated the principle of the method consists in determining the specific gravity of the liquid or solution1 and thereafter taking the percentage of the body in solution from the corresponding specific gravity in a table4 ,these tables are carefully prepared by gravimetric determinations of the bodies in solution of known densities1 varying by small amounts and calculation of the percentages for the intervening increments or decrements of density4 ,this tabulation is accomplished at definite temperatures and the process of analysis secured thereby is rapid and accurate1 with pure or nearly pure solutions4 #di4 ,determination of ,density4--,while not strictly correct from a physical point of view1 the terms density and specific gravity are here used synonymously and refer to a direct comparison of the weights of equal volumes of pure water and of the solution in question1 at the temperature named4 ,when not otherwise stated1 the temperature of the solution is assumed to be #ae4e4 ,illustration3 ,,figure #bg4 ,,common ,,forms ,,of ,,pyknometers4 ,the simplest method of determining the density of a solution is to get the weight of a definite volume thereof4 ,this is conveniently accomplished by the use of a pyknometer4 ,a pyknometer is any vessel capable of holding a definite volume of a liquid in a form suited to weighing4 ,it may be a simple flask with a narrow neck distinctly marked1 or a flask with a ground perforated stopper1 which1 when inserted1 secures always the same volume of liquid contents4 ,a very common form of pyknometer is one in which the central stopper carries a thermometer and the constancy of volume is secured by a side tubulure of very small or even capillary dimensions1 which is closed by a ground glass cap4 ,the apparatus may not even be of flask form1 but assume a quite different shape as in ,sprengel's tube4 ,pyknometers are often made to hold an even number of cubic centimeters1 but the only advantage of this is in the ease of calculation which it secures4 ,as a rule1 it will be found necessary to calibrate even these1 and then the apparent advantage will be easily lost4 ,a flask which is graduated to hold fifty cubic centimeters1 may1 in a few years1 change its volume at least slightly1 due to molecular changes in the glass4 ,some of the different forms of pyknometers are shown in the accompanying figures4 ,in use the pyknometer should be filled with pure water of the desired temperature and weighed4 ,from the total weight the tare of the flask and stopper1 weighed clean and dry1 is to be deducted4 ,the remainder is the weight of the volume of water of the temperature noted1 which the pyknometer holds4 ,the weight of the solution under examination is taken in the same way and at the same temperature1 and thus a direct comparison between the two liquids is secured4 ,example4--,let the weight of the pyknometer be #ae4bihe grams4 and its weight with pure water at #ae4e be #bf4icbg 0 ,then the weight of water is #aa4fcdb 0 ,the weight filled with the sugar solution is #bh4cbfc 0 ,then the weight of the sugar solution is #ac4jbgh 0 ,the specific gravity of the sugar solution is therefore1 #ac4jbgh #aa4fcdb #a4aaih4 ,for strictly accurate results the weight must be corrected for the volume of air displaced1 or in other words1 be reduced to weights in vacuo4 ,this however is unnecessary for the ordinary operations of agricultural analysis4 ,if the volume of the pyknometer be desired1 it can be calculated from the weight of pure water which it holds1 one cubic centimeter of pure water weighing one gram at #d4 ,the weights of one cubic centimeter of water at each degree of temperature from #a to #dj1 are given in the following table3 ,,table ,,showing ,,weights ,,of ,,one ,,cubic ,,centimeter ,,of ,,pure ,,water ,,at ,,temperatures ,,varying ,,from #a ,,to #dj4 ,weight1 ,weight1 ,temperature4 ,gram4 ,temperature4 ,gram4 #j #j4iiihga #ba #j4iihjdg #a #j4iiiibh #bb #j4iighbf #b #j4iiiifi #bc #j4iigfja #c #j4iiiiia #bd #j4iigcfg #d #a4jjjjjj #be #j4iigabj #e #j4iiiiij #bf #j4iifhff #f #j4iiiigj #bg #j4iiffjc #g #j4iiiicc #bh #j4iihcca #h #j4iiihhf #bi #j4iiejea #i #j4iiihbd #cj #j4iiegfe #aj #j4iiigdg #ca #j4iiedja #aa #j4iiifee #cb #j4iiejhg #ab #j4iiiedi #cc #j4iidgfe #ac #j4iiidcj #cd #j4iiddcf #ad #j4iiibii #ce #j4iidjih #ae #j4iiiafj #cf #j4iicgbj #af #j4iiijjb #cg #j4iiccgj #ag #j4iihhda #ch #j4iicjcj #ah #j4iihfed #ci #j4iibfhj #ai #j4iihdfj #dj #j4iibccj #bj #j4iihbei ,from the table and the weight of water found1 the volume of the pyknometer is easily calculated4 ,example4--,let the weight of water found be #aa4gbhib grams1 and the temperature #bj4 ,then the volume of the flask is equal to #aa4gbhib #j4iihbei1 viz41 #aa4ie cubic centimeters4 #ej4 ,use of ,pyknometer at ,high ,temperatures4--,it is often found desirable to determine the density of a liquid at temperatures above that of the laboratory1 e4 g41 at the boiling-point of water4 ,this is easily accomplished by following the directions given below3 ,weight of ,flask4--,use a small pyknometer of from twenty-five to thirty cubic centimeters capacity4 ,the stopper should be beveled to a fine edge on top and the lower end should be slightly concave to avoid any trapping of air4 ,the flask is to be thoroughly washed with hot water1 alcohol and ether1 and then dried for some time at #ajj4 ,after cooling in a desiccator the weight of the flask and stopper is accurately determined4#bg ,illustration3 ,,figure #bh4 ,,bath ,,for ,,pyknometers4 ,weight of ,water4--,the flask in an appropriate holder1 ,fig4 #bh1 conveniently made of galvanized iron1 is filled with freshly boiled and hot distilled water and placed in a bath of pure1 very hot distilled water1 in such a way that it is entirely surrounded by the liquid with the exception of the top4 ,the water of the bath is kept in brisk ebullition for thirty minutes1 any evaporation from the flask being replaced by the addition of boiling distilled water4 ,the stopper should be kept for a few minutes before use in hot distilled water and is then inserted1 the flask removed1 wiped dry1 and1 after it is nearly cooled to room temperature1 placed in the balance and weighed when balance temperature is reached4 ,a convenient size of holder will enable the analyst to use eight or ten flasks at once4 ,the temperature at which water boils in each locality may also be determined2 but unless at very high altitudes1 or on days of unusual barometric disturbance the variations will not be great1 and will not appreciably affect the results4 #ea4 ,alternate ,method of ,estimating the ,weight of ,water in ,flasks4--,formulas for calculating the volume ,v1 in cubic centimeters1 of a glass vessel from the weight ,p of water at the temperature t contained therein1 and the volume ,v at any other temperature t' are given by ,landolt and ,brnstein4#bh ,they are as follows3 p ,v ,p --- d p ,v ,p ---- #a 7t- t7 d p weight 7in brass weights7 of one cubic centimeter ,h,o in vacuo4 ,this is so nearly one gram that it will not affect the result in the fifth place of decimals and may therefore be disregarded4 ,hence the formula stands3 #a ,v ,p ---- #a 7t-t72 in which d d density of water at temperature t4 #j4jjjjbe1 the cubical expansion coefficient of glass4 ,from this volume the weight of the water may be readily obtained by referring to tables #ac1 #ad and #ae;a in ,landolt and ,brnstein's book4 #eb4 ,example ,showing ,determination of ,specific ,gravity of a ,fat4--,the flask is emptied of its water1 rinsed with alcohol and ether1 and dried again for a few minutes at #ajj4 ,it is then filled with the dry1 hot1 fresh-filtered fat1 which should be entirely free from air bubbles4 ,the stoppered flask is then replaced in the water-bath1 kept for thirty minutes at the temperature of boiling water1 removed1 and treated as above4 ,the weight of fat having been determined1 the specific gravity is obtained by dividing it by the weight of water previously found4 ,example4 ,grams4 ,weight of flask1 dry #aj4jaig ,weight of flask1 plus water #cg4cdab ,weight of water #bg4cbae ,weight of flask1 plus fat #cd4faaa ,weight of fat #bd4eiad ,specific gravity #bd4eiad #bg4cbae #j4ijjjh4 ,the weight of the flask dry and empty and the weight of water at #ii to #ajj contained therein may be used constantly if great care be taken in handling and cleaning the apparatus4 ,example4 ,grams4 ,weight of flask1 dry and empty #aj4jjbh ,weight of flask after three weeks' use #aj4jjcj ,illustration3 ,,figure #bi4 ,,aereometers1 ,,pyknometers1 ,,and ,,hydrostatic ,,balance4 #ec4 ,determination of ,density by the ,hydrostatic ,balance4--,while the pyknometer is useful in control work and in fixing standards of comparison1 it is not used extensively in practical work4 ,quicker methods of determination are desired in such work1 and these are found in the use of other forms of apparatus4 ,a convenient method of operation consists in determining the weight of a sinker1 whose exact weights in air and in pure water of a definite temperature1 have been previously determined4 ,the instrument devised by ,mohr and modified by ,westphal1 is based upon that principle1 and is extensively used in practical work4 ,the construction of this apparatus and also that of the pyknometers and areometers is shown in the illustrations1 figures #bi and #cj4 ,illustration3 ,,figure #cj4 ,,hydrostatic ,,balance4 ,the weight of the sinker is so adjusted that the index of the balance arm marks zero when the sinker is wholly immersed in pure water at the standard temperature4 ,the density of a solution of sugar at the same temperature1 is then determined by placing the rider-weights on the divided arm of the balance1 until the index again marks zero4 ,the density can then be read directly from the position of the weights in the arm of the balance or calculated therefrom4 #ed4 ,the ,areometric ,method4--,the most rapid method of determining the density of a solution and the one in most common use1 is based on the distance to which a heavy bulb with a slender graduated stem will sink therein4 ,an instrument of this kind is called an areometer4 ,many forms of this instrument are employed but they all depend on the same principle and differ only in the manner of graduation4 ,the one of widest application has the stem graduated in such a manner as to give directly the specific gravity of the solution in which it is placed4 ,others are made with a special graduation giving directly the percentage of solid matter in the solution4 ,these instruments can be used only for the special purposes for which they are constructed4 ,other forms are provided with an arbitrary graduation1 the numbers of which by appropriate tables can be converted into expressions of specific gravity or of per cents of dissolved matters4 ,it is not practicable to give here1 a discussion of the principles of the construction of areometers4#bi ,the two which are commonly used1 are the baum hydrometer and the balling or brix spindle4 ,in the baum instrument the zero of the scale is fixed at the point marked by the surface of distilled water at #ae1 and the point to which it sinks in pure monohydrated sulfuric acid at the same temperature is marked #ff1 corresponding to a specific gravity of #a4hdbg4 ,the specific gravity corresponding to any degree of the scale1 may be calculated in the absence of a table giving it1 by the following formula #add4c ,p -----------4 #add4c - d ,in this formula ,p is the density and d the degree of the scale4#cj ,in former times the baum instruments were graduated with a solution of common salt and a different formula was employed for calculating specific gravity1 but these older instruments are no longer in common use4 ,the following table shows the specific gravities of solutions corresponding to baum degrees from #a to #ge consecutively#ca3 ,degree ,specific ,degree ,specific ,degree ,specific ,degree ,specific baum gravity baum gravity baum gravity baum gravity #j #a4jjjj #ai #a4aeaf #ch #a4cegd #eg #a4febg #a #a4jjfi #bj #a4afjh #ci #a4cgjc #eh #a4fgai #b #a4jadj #ba #a4agjb #dj #a4chcd #ei #a4fiae #c #a4jbab #bb #a4agih #da #a4cifh #fj #a4gaae #d #a4jbhe #bc #a4ahie #db #a4dajd #fa #a4gcba #e #a4jceh #bd #a4aiid #dc #a4dbdd #fb #a4geca #f #a4jdcc #be #a4bjie #dd #a4dchf #fc #a4ggdh #g #a4jeji #bf #a4baig #de #a4decj #fd #a4gifh #h #a4jehf #bg #a4bcja #df #a4dfgh #fe #a4haid #i #a4jffe #bh #a4bdjg #dg #a4dhbi #ff #a4hdbg #aj #a4jgdd #bi #a4bead #dh #a4dihc #fg #a4hffe #aa #a4jhbe #cj #a4bfbd #di #a4eadj #fh #a4hiji #ab #a4jijf #ca #a4bgce #ej #a4ecja #fi #a4iafa #ac #a4jihi #cb #a4bhdi #ea #a4edfe #gj #a4idah #ad #a4ajgd #cc #a4bifd #eb #a4efcb #ga #a4ifhc #ae #a4aaei #cd #a4cjha #ec #a4ehjb #gb #a4iiee #af #a4abdf #ce #a4cbja #ed #a4eigh #gc #b4jbce #ag #a4acce #cf #a4ccbc #ee #a4faeg #gd #b4jebc #ah #a4adbd #cg #a4cddg #ef #a4fcdj #ge #b4jhai #ee4 ,correction for ,temperature4--,the baum hydrometer should be used at the temperature for which it is graduated1 usually #ae4 ,in this country the mean temperature of our working rooms is above #ae4 ,the liquid in the hydrometer flask should therefore be cooled to a trifle below #ae1 or kept in a bath exactly at #ae while the observation is made4 ,when this is not convenient1 the observation may be made at any temperature1 and the reading corrected as follows3 ,when the temperature is above #ae multiply the difference between the observed temperature and fifteen1 by #j4jdga and add the product to the observed reading of the baum hydrometer2 when the temperature on the other hand1 is below fifteen1 the corresponding product is subtracted4#cb #ef4 ,the ,balling or ,brix ,hydrometer4--,the object of the balling or brix instrument is to give in direct percentages the solid matter in solution4 ,it is evident that for this purpose the instrument must be graduated for a particular kind of material1 since ten per cent of sugar in solution1 might have a very different specific gravity from a similar quantity of another body4 ,instruments of this kind graduated for pure sugar1 find a large use in technical sugar analysis4 ,to attain a greater accuracy and avoid an instrument with too long a stem1 the brix hydrometers are made in sets4 ,a convenient arrangement is to have a set of three graduated as follows2 one from #j to #cj1 one from #be to #ej1 and one from #de to #he4 ,when the percentage of solid matter dissolved is over seventy the readings of the scale are not very reliable4 #eg4 ,correction for ,temperature4--,the brix as the baum scale is graduated at a fixed temperature4 ,this temperature is usually #ag4e4 ,the following table shows the corrections to be applied to the scale reading when made at any other temperature3#cc ,,per ,,cent ,,of ,,sugar ,,in ,,solution4 #j4 #e4 #aj4 #ae4 #bj4 #be4 #cj4 #ce4 #dj4 #ej4 #fj4 #gj4 #ge4 ,temp4 ,to be subtracted from the degree read4 #j #j4ag #j4cj #j4da #j4eb #j4fb #j4gb #j4hb #j4ib #j4ih #a4aa #a4bb #a4be #a4bi #e #j4bc #j4cj #j4cg #j4dd #j4eb #j4ei #j4fe #j4gb #j4ge #j4hj #j4hh #j4ia #j4id #aj #j4bj #j4bf #j4bi #j4cc #j4cf #j4ci #j4db #j4de #j4dh #j4ej #j4ed #j4eh #j4fa #aa #j4ah #j4bc #j4bf #j4bh #j4ca #j4cd #j4cf #j4ci #j4da #j4dc #j4dg #j4ej #j4ec #ab #j4af #j4bj #j4bb #j4bd #j4bf #j4bi #j4ca #j4cc #j4cd #j4cf #j4dj #j4db #j4df #ac #j4ad #j4ah #j4ai #j4ba #j4bb #j4bd #j4bf #j4bg #j4bh #j4bi #j4cc #j4ce #j4ci #ad #j4ab #j4ae #j4af #j4ag #j4ah #j4ai #j4ba #j4bb #j4bb #j4bc #j4bf #j4bh #j4cb #ae #j4ji #j4aa #j4ab #j4ad #j4ad #j4ae #j4af #j4af #j4ag #j4ag #j4ai #j4ba #j4be #af #j4jf #j4jg #j4jh #j4ji #j4aj #j4aj #j4aa #j4ab #j4ab #j4ab #j4ad #j4af #j4ah #ag #j4jb #j4jb #j4jc #j4jc #j4jc #j4jd #j4jd #j4jd #j4jd #j4jd #j4je #j4je #j4jf ,to be added to the degree read4 #ah #j4jb #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jc #j4jb #ai #j4jf #j4jh #j4jh #j4ji #j4ji #j4aj #j4aj #j4aj #j4aj #j4aj #j4aj #j4jh #j4jf #bj #j4aa #j4ad #j4ae #j4ag #j4ag #j4ah #j4ah #j4ah #j4ai #j4ai #j4ah #j4ae #j4aa #ba #j4af #j4bj #j4bb #j4bd #j4bd #j4be #j4be #j4be #j4bf #j4bf #j4be #j4bb #j4ah #bb #j4ba #j4bf #j4bh #j4ca #j4ca #j4cb #j4cb #j4cb #j4cc #j4cd #j4cb #j4bi #j4be #bc #j4bg #j4cb #j4ce #j4cg #j4ch #j4ci #j4ci #j4ci #j4dj #j4db #j4ci #j4cf #j4cc #bd #j4cb #j4ch #j4da #j4dc #j4dd #j4df #j4df #j4dg #j4dg #j4ej #j4df #j4dc #j4dj #be #j4cg #j4dd #j4dg #j4di #j4ea #j4ec #j4ed #j4ee #j4ee #j4eh #j4ed #j4ea #j4dh #bf #j4dc #j4ej #j4ed #j4ef #j4eh #j4fj #j4fa #j4fb #j4fb #j4ff #j4fb #j4eh #j4ee #bg #j4di #j4eg #j4fa #j4fc #j4fe #j4fh #j4fh #j4fi #j4gj #j4gd #j4gj #j4fe #j4fb #bh #j4ef #j4fd #j4fh #j4gj #j4gb #j4gf #j4gf #j4gh #j4gh #j4hb #j4gh #j4gb #j4gj #bi #j4fc #j4ga #j4ge #j4gh #j4gi #j4hd #j4hd #j4hf #j4hf #j4ij #j4hh #j4hj #j4gh #cj #j4gj #j4gh #j4hb #j4hg #j4hg #j4ib #j4ib #j4id #j4id #j4ih #j4id #j4hh #j4hf #ce #a4aj #a4ag #a4bb #a4bd #a4cj #a4cb #a4cc #a4ce #a4cf #a4ci #a4cd #a4bg #a4be #dj #a4ej #a4fa #a4fg #a4ga #a4gc #a4gi #a4gi #a4hj #a4hb #a4hc #a4gh #a4fi #a4fe #ej ---- #b4fe #b4ga #b4gd #b4gh #b4hj #b4hj #b4hj #b4hj #b4gi #b4gj #b4ef #b4ea #fj ---- #c4hg #c4hh #c4hh #c4hh #c4hh #c4hh #c4hh #c4ij #c4hb #c4gj #c4dc #c4da #gj ---- ---- #e4ah #e4bj #e4ad #e4ac #e4aj #e4jh #e4jf #d4ij #d4gb #d4dg #d4ce #hj ---- ---- #f4fb #f4ei #f4ed #f4af #f4ch #f4cj #f4bf #f4jf #e4hb #e4ej #e4cc ,according to observations of ,gerlach1 the correction for temperature varies with the concentration of the solution and the range of temperature as shown in the table4 #eh4 ,comparison of ,brix and ,baum ,degrees4--,the following table shows the degree baum and the specific gravity of a sugar solution for each degree brix 7per cent of sugar in solution7 from zero to ninety-five3#cd ,degree ,degree ,specific ,degree ,degree ,specific brix4 baum4 gravity4 brix4 baum4 gravity4 #a4j #j4f #a4jjchh #cg4j #bj4g #a4afdac #b4j #a4a #a4jjggi #ch4j #ba4b #a4afibj #c4j #a4g #a4jaagc #ci4j #ba4h #a4agdcj #d4j #b4c #a4jaegj #dj4j #bb4c #a4agidc #e4j #b4h #a4jaigj #da4j #bb4i #a4ahdfj #f4j #c4d #a4jbcgc #db4j #bc4d #a4ahiha #g4j #d4j #a4jbggi #dc4j #bd4j #a4aieje #h4j #d4e #a4jcahg #dd4j #bd4e #a4bjjcc #i4j #e4a #a4jceii #de4j #be4j #a4bjefe #aj4j #e4g #a4jdjad #df4j #be4f #a4baajj #aa4j #f4b #a4jddca #dg4j #bf4a #a4bafci #ab4j #f4h #a4jdheb #dh4j #bf4f #a4bbahb #ac4j #g4d #a4jebgf #di4j #bg4b #a4bbabh #ad4j #g4i #a4jegjc #ej4j #bg4g #a4bcbgh #ae4j #h4e #a4jfacc #ea4j #bh4b #a4bchcb #af4j #i4j #a4jfeff #eb4j #bh4h #a4bdcij #ag4j #i4f #a4jgjjb #ec4j #bi4c #a4bdiea #ah4j #aj4a #a4jgdda #ed4j #bi4h #a4beeag #ai4j #aj4g #a4jghhd #ee4j #cj4d #a4bfjhf #bj4j #aa4c #a4jhcbi #ef4j #cj4i #a4bffeh #ba4j #aa4h #a4jhggh #eg4j #ca4d #a4bgbce #bb4j #ab4d #a4jibca #eh4j #ca4i #a4bghaf #bc4j #ac4j #a4jifhf #ei4j #cb4e #a4bhdjj #bd4j #ac4e #a4ajade #fj4j #cc4j #a4bhihi #be4j #ad4a #a4ajfjg #fa4j #cc4e #a4bieha #bf4j #ad4f #a4aajgb #fb4j #cd4j #a4cjagg #bg4j #ae4b #a4aaeda #fc4j #cd4e #a4cjagg #bh4j #ae4g #a4abjac #fd4j #ce4a #a4cacha #bi4j #af4c #a4abdhh #fe4j #ce4f #a4caihi #cj4j #af4h #a4abifg #ff4j #cf4a #a4cbfja #ca4j #ag4d #a4acddi #fg4j #cf4f #a4ccbag #cb4j #ah4j #a4acicd #fh4j #cg4a #a4cchcf #cc4j #ah4e #a4addbc #fi4j #cg4f #a4cddfj #cd4j #ai4a #a4adiae #gj4j #ch4a #a4cejhh #ce4j #ai4f #a4aedaa #ga4j #ch4f #a4cegbj #cf4j #bj4a #a4aeiaa #gb4j #ci4a #a4cfcee #gc4j #ci4f #a4cfiie #he4j #de4e #a4ddihf #gd4j #dj4a #a4cgfci #hf4j #df4j #a4defgh #ge4j #dj4f #a4chbhg #hg4j #df4e #a4dfcgd #gf4j #da4a #a4chici #hh4j #dg4j #a4dgjgd #gg4j #da4f #a4cieie #hi4j #dg4e #a4dgggh #gh4j #db4a #a4djbed #ij4j #di4i #a4dhdhf #gi4j #db4f #a4djiah #ia4j #dh4d #a4diaii #hj4j #dc4a #a4daehf #ib4j #dh4i #a4diiae #ha4j #dc4f #a4dbbeh #ic4j #di4c #a4ejfce #hb4j #dd4a #a4dbicd #id4j #di4h #a4eacei #hc4j #dd4f #a4dcfad #ie4j #ej4c #a4ebjhg #hd4j #de4a #a4ddbih #ei4 ,error ,due to ,impurities4--,the fact that equal per cents of solid bodies in solution affect the specific gravity in different degrees has already been noted4 ,the specific gravities of the solutions of the common sugars1 however1 are so nearly the same for equal per cents of solid matter in solution as to render the use of a brix hydrometer quite general for technical purpose4 ,for the mineral salts which often occur in sugar solutions the case is quite different4 ,a twenty per cent solution of cane sugar at #ag4e has a specific gravity #a4jhcbi and of dextrose #a4jhcaj1 practically identical4 ,but a solution of calcium acetate of similar strength has a specific gravity of #a4jhgd2 of sodium sulfate #a4jhjg1 and of potassium nitrate #a4acei4 ,this latter number would correspond to a sugar content of nearly twenty-seven per cent4 ,the brix scale can1 therefore1 be regarded as giving only approximately the percentage of solid matter in sugar solutions and1 while useful in technical work1 should never be relied upon for exact analytical data4 ,,the ,,determination ,,of ,,sugar ,,with ,,polarized ,,light4 #fj4 ,optical ,properties of ,natural ,sugars4--,the solutions of all natural sugars have the property of deflecting the plane of polarized light and the degree of deflection corresponds to the quantity of sugar in solution4 ,by measuring the amplitude of the rotation produced the percentage of sugar in the solution can be determined4 ,in order to secure accuracy in the determinations it is necessary that only one kind of sugar be present1 or1 if more than one1 that the quantities of all but one be determined by other means1 and the disturbances produced thereby in the total rotation be properly arranged4 ,in point of fact the process in practice is applied chiefly to cane and milk sugars1 both of which occur in nature in an approximately pure state4 ,the process is also useful in determining cane sugar when mixed with other kinds1 by reason of the fact that this sugar after hydrolysis by treatment with a weak acid for a long or a strong acid for a short time1 definitely changes its rotating power4 ,since1 by the same treatment1 the rotating power of other sugars which may be present is only slightly altered1 the total disturbance produced is approximately due to the inversion of the cane sugar4 ,dextrose and maltose arising from the hydrolysis of starch may also be determined with a fair degree of accuracy by their deportment with polarized light4 ,when a solution of natural sugars shows negative results when examined with polarized light1 it is due to an admixture of two or more sugars of opposite polarizing powers in such proportions as to produce neutrality4 ,this condition often occurs in the examination of honeys or in submitting artificial sugars to polarimetric observations4 ,in the latter case the neutrality is caused by the tendency manifested by artificially produced sugars to form twin compounds of optically opposite qualities4 ,the instrument used for measuring the degree of deflection produced in a plane of polarized light is called a polariscope1 polarimeter1 or optical saccharimeter4 ,for a theoretical discussion of the principles of polarization and the application of these principles in the construction of polariscopes1 the reader is referred to the standard works on optics and the construction of optical instruments4#ce ,for the purposes of this work a description of the instruments commonly employed and the methods of using them will be sufficient4 #fa4 ,polarized ,light4--,when a ray of light has been repeatedly reflected from bright surfaces or when it passes through certain crystalline bodies it acquires peculiar properties and is said to be polarized4 ,polarization is therefore a term applied to a phenomenon of light1 in which the vibrations of the ether are supposed to be restricted to a particular form of an ellipse whose axes remain fixed in direction4 ,if the ellipse become a straight line it is called plane polarization4 ,this well-known phenomenon is most easily produced by a nicol prism1 consisting of a cut crystal of calcium carbonate 7,iceland spar74 ,this rhombohedral crystal1 the natural ends of which form angles of #ga and #aji1 respectively1 with the opposite edges of its principal section1 is prepared as follows3 ,the ends of the crystals are ground until the angles just mentioned become #fh and #aab4 ,the crystal is then divided diagonally at right angles with the planes of the ends and with the principal section1 and after the new surfaces are polished they are joined again by canada balsam4 ,the principal section of this prism passes through the shorter diagonal of the two rhombic ends4 ,if now a ray of light fall on one of the ends of this prism1 parallel with the edge of its longer side1 it suffers double refraction1 and each ray is plane polarized1 the one at right angles with the other4 ,that part of the entering ray of light which is most refracted is called the ordinary and the other the extraordinary ray4 ,the refractive index of the film of balsam being intermediate between those of the rays1 permits the total reflection of the ordinary ray1 which1 passing to the blackened sides of the prism1 is absorbed4 ,the extraordinary ray passes the film of balsam without deviation and emerges from the prism in a direction parallel with the incident ray1 having1 however1 only half of its luminous intensity4 ,two such prisms1 properly mounted1 furnish the essential parts of a polarizing apparatus4 ,they are called the polarizer and the analyzer1 respectively4 ,if now the plane of vibration in each prism be regarded as coincident with its principal section1 the following phenomena are observed3 ,if the prisms are so placed that the principal sections lie in the prolongation of the same plane1 then the extraordinary polarized ray from the polarizer passes into the analyzer1 which practically may be regarded in this position as a continuation of the same prism4 ,it happens1 therefore1 that the extraordinary polarized ray passes through the analyzer exactly as it did through the polarizer1 and is not reflected by the film of balsam1 but emerges from the analyzer in seemingly the same condition as from the polarizer4 ,if now the analyzer be rotated #ahj1 bringing the principal section again in the same plane1 the same phenomenon is observed4 ,but if the rotation be in either direction only #ij1 then the polarized ray from the first prism1 incident on the second1 deports itself exactly as the ordinary ray1 and on meeting the film of balsam is totally reflected4 ,the field of vision1 therefore1 is perfectly dark4 ,in all other inclinations of the planes of the principal sections of the two prisms the ray incident in the analyzer is separated into two1 an ordinary and extraordinary1 varying in luminous intensity in proportion to the square of the cosine of the angle of the two planes4 ,illustration3 ,,figure #ca4 ,,course ,,of ,,rays ,,of ,,light ,,in ,a ,,nicol4 ,thus1 by gradually turning the analyzer1 the field of vision passes slowly from maximum luminosity to complete obscurity4 ,the expression crossed nicols refers to the latter condition of the field of vision4 #fb4 ,description of the ,prism4--,in a nicol made as described above1 ,fig4 #ca1 suppose a ray of light parallel with the longer side of the prism be incident to the end a b at m4 ,by the double refracting power of the spar the ray is divided into two1 which traverse the first half of the prism4 ,the two rays are polarized at right angles to one another4 ,the less refracted ray when it strikes the film of ,canada balsam passes through it without interference4 ,the more refracted ray strikes the balsam at o at such an angle as to be totally reflected and made to pass out of the prism in the direction o r4 ,if the prism be blackened at the surface the ray will be entirely absorbed4 ,the other ray passes on through the other half of the prism and emerges in the direction of qs4 ,it is evident that the emergent light from a nicol has only half the illuminating power possessed by the immergent rays4 ,the polarized plane of light from the nicol just described may be regarded as passing also into a second nicol of essentially the same construction as the first4 ,this second nicol1 called the analyzer1 is so constructed as to revolve freely about its longitudinal axis1 and is attached to a graduated circle in such a way that the degree of rotation can be accurately read4 ,if the planes of polarization of the two nicols are coincident when prolonged1 the ray of light passing from the first nicol will pass through the second practically unchanged in character or intensity4 ,if1 however1 the analyzing nicol be turned until the plane of polarization is at right angles to that of the polarizer the immergent ray will suffer refraction in such a manner as to be totally reflected when reaching the film of balsam and will be thus entirely lost4 ,in making a complete revolution of the analyzer1 therefore1 two positions of maximum intensity of light and two of darkness will be observed4 ,in intermediate positions the ray immergent to the analyzer will be separated as in the first instance into two rays g p varying intensities1 one of which will be always totally reflected4 ,illustration3 ,,figure #cb4 ,,theory ,,of ,,the ,,nicol4 ,in ,fig4 #cb is given a more detailed illustration of the action of the rays of light4 ,the film of balsam is represented as enlarged and of the thickness bb4 ,draw the perpendiculars represented by the dotted lines n n1 n n1 n n and n n4 ,in passing into the prism at m both refracted rays are bent towards the normal m n4 ,the degree of deflection depends on the refractive index of the two rays #a4eb and #a4ff respectively4 ,the refractive index of the extraordinary ray in calcspar being #a4eb1 and in ,canada balsam #a4ed1 it suffers but little disturbance in passing from one to the other4 ,on the other hand the balsam1 being considerably less refractive for the ordinary ray than the calcspar1 causes that ray to diverge outwards from the normal o n1 and to such a degree as to suffer total reflection4 ,the critical angle1 that is the angle at which a ray issuing from a more refractive into a less refractive medium1 emerges just parallel to the bounding surfaces1 depends on the relative index of refraction4 ,in the case under consideration the ratio for balsam and spar is #a4ed_/a4ff #j4ibh sin #fh4 ,therefore the limiting value of m o n so that m o may just emerge in the direction od is #fh4 ,if now mo were parallel to o d the angle m o n1 would be just #fh1 being opposite b a d4 which has been ground to #fh in the construction of the prism4 ,but in passing into the prism1 m o is refracted so that the angle m o n is greater than b a d4 ,it is therefore always certain that by grinding b a d to #fh the ordinary ray m o will be with certainty entirely thrown out in every case4 ,in respect of the analyzing nicol the following additional observations will be found useful4 ,in all uniaxial crystals there are two directions at right angles to each other1 one of greatest and one of least resistance to the propagation of luminous vibrations4 ,these planes are in the direction of the principal axis and at right angles thereto4 ,only light vibrating in these two directions can be transmitted through calcspar2 and all incident light propagated by vibrations in a plane at any other angle to the principal section is resolved into two such component rays4 ,but the velocities of transmission in the two directions are unequal1 that is1 the refractive index of the spar for the two rays is different4 ,if the analyzing nicol be so adjusted as to receive the emergent light from the polarizer when the corresponding planes of the two prisms are coincident when extended1 the emergent extraordinary ray falling into a plane of the same resistance as that it had just left is propagated through the second nicol with the same velocity that it passed the first one4 ,it is therefore similarly refracted4 ,if1 however1 the two prisms be so arranged that corresponding planes cross then the extraordinary ray falls into a plane which it traverses with greater velocity than it had before and is accordingly refracted and takes the course which ends in total reflection at the film of balsam4 ,no light therefore can pass through the prism in that position4 ,if any other substance1 as for instance a solution of sugar1 capable of rotating a plane of polarized light1 be interposed between the two nicols the effect produced is the same as if the analyzer had been turned to a corresponding degree4 ,when the analyzer is turned to that degree the corresponding planes again coincide and the light passes4 ,this is the principle on which the construction of all polarizing instruments is based4#cf #fc4 ,the ,polariscope4--,a polariscope for the examination of solutions of sugar consists essentially of a prism for polarizing the light1 called a nicol1 a tube of definite length for holding the sugar solution1 a second nicol made movable on its axis for adjustment to the degree of rotation and a graduated arc for measuring it4 ,instead of having the second nicol movable1 many instruments have an adjusting wedge of quartz of opposite polarizing power to the sugar1 by means of which the displacement produced on the polarized plane is corrected4 ,a graduated scale and vernier serve to measure the movement of the wedges and give in certain conditions the desired reading of the percentage of sugar present4 ,among the multitude of instruments which have been devised for analytical purposes1 only three will be found in common use1 and the scope of this volume will not allow space for a description of a greater number4 ,for a practical discussion of the principles of polarization and their application to optical saccharimetry1 the reader may conveniently refer to the excellent manuals of ,sidersky1 ,tucker1 ,landolt1 and ,wiechmann4#cg #fd4 ,kinds of ,polariscopes4--,the simplest form of a polarizing apparatus consists of two nicol prisms1 one of which1 viz41 the analyzer1 is capable of rotation about its long axis4 ,the prolongation of this axis is continuous with that of the other prism1 viz41 the polarizer4 ,the two prisms are sufficiently removed from each other to allow of the interposition of the polarizing body whose rotatory power is to be measured4 ,for purposes of description three kinds of polarimeters may be mentioned4 #a4 ,instruments in which the deviation of the plane of polarization is measured by turning the analyzer about its axis4 ,instruments of this kind conform to the simple type first mentioned1 and are coeteris paribus the best4 ,the ,laurent1 ,wild1 ,landolt-,lippich1 etc41 belong to this class4 #b4 ,instruments in which both nicols are fixed and the direction of the plane of polarized light corrected by the interposition of a wedge of a solid polarizing body4 ,belonging to this class are the apparatus of ,soleil1 ,duboscq1 ,scheibler1 and the compensating apparatus of ,schmidt and ,haensch4 #c4 ,apparatus in which the analyzer is set at a constant angle with the polarizer1 and the compensation secured by varying the length or concentration of the interposed polarizing liquid4 ,the apparatus of ,trannin belongs to this class4 #fe4 ,appearance of ,field of ,vision4--,polarimeters are also classified in respect of the appearance of the field of vision4 #a4 ,tint ,instruments4--,the field of vision in these instruments in every position of the nicols1 except that on which the plane of vibration of the polarized light is coincident with the three principal sections1 is composed of two semi-disks of different colors4 #b4 ,shadow ,instruments4--,the field of vision in this class of polarimeters in all except neutral positions1 is composed of two semi-disks1 one dark and one yellow4 ,as the neutral position is approximated the two disks gradually assume a light yellow color1 and when neutrality is reached they appear to be equally colored4 ,the ,laurent1 ,schmidt and ,haensch shadow and ,landolt-,lippich instruments1 are of this class4 #c4 ,striated ,instruments4--,in this class the field of vision is striated4 ,the lines may be tinted as in ,wild's polaristrobometer or black1 as in the ,duboscq and ,trannin instruments4 ,the neutral position is indicated either by the disappearance of the striae 7,wild7 or by the phenomenon of their becoming continuous4 7,duboscq1 ,trannin47 #ff4 ,character of ,light ,used4--,polariscopes may be further divided into two classes1 based on the kind of light employed4 #a4 ,instruments which ,use ,ordinary ,white ,light4--7,oil lamp1 etc47 ,scheibler1 ,schmidt and ,haensch4 #b4 ,instruments ,employing ,monochromatic ,light4--7,sodium flame1 etc47 ,laurent1 ,landolt-,lippich1 etc4 #fg4 ,interchangeable ,instruments4--,some of the instruments in common use are arranged to be used either with ordinary lamp or gas light1 or with a monochromatic flame4 ,laurent's polarimeter is one of this kind4 ,the compensating instruments also may have the field of vision arranged for tints or shadows4 ,theoretically the best instrument would be one in which the light is purely monochromatic1 the field of vision a shadow1 and the compensation secured by the rotation of the second nicol4 ,the accuracy of an instrument depends1 however1 on the skill and care with which it is constructed and used4 ,with quartz wedges properly ground and mounted1 and with ordinary white light1 polariscopes may be obtained which give readings as accurate as can be desired4 ,since many persons are more or less affected with color-blindness1 the shadow are to be preferred to the tint fields of vision4 ,for practical use in sugar analysis the white light is much more convenient than the monochromatic light4 ,for purposes of general investigation the polarimeters built on the model of the laurent are to be preferred to all others4 ,such instruments are not only provided with a scale which shows the percentage of sucrose in a solution1 but also with a scale and vernier by means of which the angular rotation which the plane of vibration has suffered1 can be accurately measured in more than one-quarter of the circle4 ,,description ,,of ,,polarizing ,,instruments4 #fh4 ,rotation ,instruments4--,this instrument has already been described as one in which the extent of deviation in the plane of polarized light caused by the intervention of an optically active substance is measured by rotating one of the nicols about its axis and measuring the degree of this rotation by a vernier on a graduated arc4 ,in ,germany these instruments are called polaristrobometers1 and in ,france polarimtrs4 ,in ,england and this country the term polariscope or polarimeter is applied without discrimination to all kinds of optical saccharimeters4 ,the polariscope of ,mitscherlich was one of the earliest in use4 ,it has now been entirely superseded by more modern and accurate instruments4 #fi4 ,the ,laurent ,instrument4--,a polariscope adapted by ,laurent to the use of monochromatic yellow light is almost exclusively used in ,france and to a considerable extent in this country4 ,in case a worker is confined to the use of a single instrument1 the one just mentioned is to be recommended as the best suited to general work4 ,it has the second nicol1 called the analyzer1 movable and the degree of rotation produced is secured in angular terms directly on a divided circle4 ,the scale is graduated both in angular measurements and in per cents of sugar for a definite degree of concentration of the solution and length of observation tube4 ,the normal solution in the laurent instrument contains #af4ai grams of pure sugar in #ajj true cubic centimeters1 and the length of the observation tube is #bjj millimeters4 ,both the angular rotation and the direct percentage of sugar can be read at the same time4 ,great accuracy can be secured by making the readings in each of the four quadrants4 ,the light is rendered yellow monochromatic by bringing into the flames of a double bunsen1 spoons made of platinum wire1 which carry fragments of fused sodium chlorid4 ,illustration3 ,,figure #cc4 ,,laurent ,,lamp4 #gj4 ,the ,laurent ,burner4--,the theory of the illumination of the laurent burner is illustrated by the accompanying ,fig4 #cc4 ,the lamp consists essentially of two bunsens1 surmounted by a chimney4#ch ,a curved spoon made of platinum gauze serves to hold the fused particles of sodium chlorid which are used to produce the yellow light4 ,the spoon is shown at ,g1 held by the arm ,f1 fastened by the key ,p4 ,the interior intense flame ,b ,b is surrounded by an exterior less highly colored flame ,a ,a4 ,it is important that the optical axis of the polariscope be directed accurately upon the disk ,b1 which is the most intense part of the illumination4 ,the point of the spoon carrying the salt should be coincident with the prolongation of the lamp ,,tt1 so that it just strikes the edge of the blue flame4 ,care should be taken not to press the spoons into the interior of the flame as by so doing the intensity of the illumination is very much diminished4 ,great care must be observed in the position of the spoon ,g1 and the platinum arm ,f being flexible1 the operator with a little patience1 will be enabled to properly place the spoon by bending it4 ,moreover1 if the spoon be pressed too far into the flame1 the melted particles of salt collecting in the bottom of ,g may drop into the lamp and occlude the orifices through which the gas enters4 ,the light of the yellow flame produced by the lamp may be further purified by passing through a prism filled with a solution of potassium dichromate1 or better1 a homogeneous disk cut from a crystal of that salt4 ,since the flame produced by the above device is not perfectly constant1 being more intense at the moment of introducing a fresh portion of the fused salt1 the author has used a lamp designed to furnish an absolutely constant flame4#ci ,this device which is shown in ,fig4 #cd1 is based on the principle of adding constantly a fresh portion of the salt to the flame4 ,the flame is thus kept perfectly uniform in its intensity4 ,the lamp consists essentially of two wheels with platinum gauze perimeters and platinum wire spokes1 driven by a clock-work ,d1 and mounted by the supports ,,aa as shown in the figure4 ,the sodium salt1 chlorid or bromid1 in dilute solution1 is placed in the porcelain crucibles ,f1 supported by ,,bb as indicated in the figure1 to such a depth that the rims of the platinum wheels dip beneath the surface as they revolve4 ,the salt is volatilized by the lamp ,e4 ,by means of the crossed bands the wheels are made to revolve in opposite directions as indicated by the arrows4 ,the solution of the salt which is taken up by the platinum net-work of the rim of the wheel1 thus has time to become perfectly dry before it enters the flame and the sputtering which a moist salt would produce is avoided4 ,at every instant1 by this arrangement1 a minute fresh portion of salt is introduced into the flame with the result of making a perfectly uniform light which can be used for hours without any perceptible variation4 ,the mechanism of the apparatus is so simple that no further description is necessary4 ,the polariscope should be so directed toward the flame as to bring into the field of vision its most luminous part4 ,the platinum wheels are adjustable and should be so arranged as to produce between them an unbroken yellow flame4 ,the wheels are eight centimeters in diameter and are driven at a rate to make one revolution in from six to ten minutes4 ,illustration3 ,,figure #cd4 ,,lamp ,,for ,,producing ,,constant ,,monochromatic ,,flame4 #ga4 ,construction of ,laurent's ,apparatus4--,the shadow polariscope invented by ,laurent is constructed as follows3 ,the polarizer is a special nicol which is not fixed in its position1 but is so arranged as to be turned through a small arc about its axis4 ,by this device1 the quantity of light passing through it can be regulated1 and the apparatus is thus useful with colored solutions which are not easily cleared by any of the common bleaching agents4 ,the greater the quantity of light admitted1 however1 the less delicate is the reading of the shadow produced4 ,the plane of polarized light emergent from this prism1 falls on a disk of glass half covered by a thin lamina of quartz which thus divides the field of vision into halves4 ,it is this semi-disk of quartz which is the distinguishing feature of the apparatus4#dj ,the polarized light thus passes without hindrance the half field of vision which is covered by the glass only1 but can not pass the quartz plate unless its axis is set in a certain way4 ,the field of vision may be thus half dark1 or both halves may be equally illuminated or equally dark according to the position of the nicol analyzer which is freely movable about its axis and carries a vernier and reading glass over a graduated circle4 ,the field of vision in the laurent may have any of the following forms4#da ,let the polarizer be first so adjusted that the plane of polarization of the transmitted pencil of light is parallel to the axis of the plate lying in the direction ,a ,b4 ,the two halves of the field of vision will then appear equally illuminated in every position of the analyzer4 ,but if the polarizing nicol be inclined to ,,ab at an angle a1 the plane of polarization of the rays passing through the quartz plate will undergo deviation through an equal angle in the opposite direction4 ,illustration3 ,,figure #ce4 ,,field ,,of ,,vision ,,of ,a ,,laurent ,,polariscope4 ,it happens from this1 that when in the uncovered half of the field1 the plane of polarization has the direction ,,ac1 in the other half it will have the direction ,,ac4 ,when the analyzer is rotated1 if its plane of polarization lie in the direction cc1 the rays polarized parallel to ,,ac will be completely extinguished and the corresponding half of the field will be dark4 ,the opposite happens when the plane of polarization lies in the direction of cc4 ,when one-half of the field is thus obscured1 the other suffers only a partial diminution in the intensity of its illumination4 ,when the middle position bb is reached in the rotation of the analyzer1 the illumination of the two halves is uniform1 and this is the point at which the zero of the scale is reached4 ,the slightest rotation of the analyzer to the right or left of this neutral point will cause a shadow to appear on one of the halves of the field1 which by an oscillatory movement of the analyzer1 seems to leap from side to side4 ,the smaller the angle a or ,,bac1 the more delicate will be the shading and the more accurate the observation4 ,this angle being adjustable by the mechanism already described1 should be made as small as will permit the admission of the quantity of light requisite for accurate observation4 ,the various pieces composing the polariscope are arranged in the following positions1 beginning on the right of ,fig4 #cf1 and passing to the left1 where the observer is seated4#db #a4 ,the lamp ,,vv1 ,,tt1 ,,aa1 or the wheel burner3 #b4 ,the lens ,b for condensing the rays and rendering them parallel3 #c4 ,the tube ,i1 blackened inside to carry the lens3 #d4 ,a thin lamina ,e1 cut from a crystal of potassium bichromate1 serving to render the sodium light more monochromatic3 ,when the saccharine liquids under examination are colored the crystal of bichromate is removed before the observation is made4 #e4 ,the polarizer ,r1 which is rotatable through a small angle by the lever ,k3 #f4 ,the lever ,,jk for rotating the tube containing the polarizer3 ,this is operated by the rod ,x extending to the left4 #g4 ,diaphragm ,d1 half covered with a lamina of quartz4 #h4 ,trough ,l for holding the observation tube3 ,in the large instrument shown in the figure1 it is more than half a meter in length and arranged to hold an observation tube #ejj millimeters long4 #i4 ,disk ,c1 carrying divided circle and arbitrary sugar scale3 #aj4 ,mirror ,m1 to throw the light of the lamp on the vernier of the scale3 ,illustration3 ,,figure #cf4 ,,laurent ,,polariscope4 #aa4 ,reading glass ,n1 carried on the same radius as the mirror and used to magnify and read the scale3 #ab4 ,device ,f1 to regulate the zero of the instrument3 #ac4 ,tube ,h1 carrying a nicol analyzer and ocular ,o for defining the field of vision3 ,this tube is rotated by the radial arm ,g1 carrying the mirror and reading glass4 #gb ,manipulation4--,the lamp having been adjusted1 the instrument1 in a dark room1 is so directed that the most luminous spot of the flame is in the line of vision4 ,an observation tube filled with water is placed in the trough and the zero of the vernier is placed accurately on the zero of the scale4 ,the even tint of the field of vision is then secured by adjusting the apparatus by the device number #ab4 #gc ,the ,soleil-,ventzke ,polariscope4--,a form of polariscope giving a colored field of vision was in use in this country almost exclusively until within ten years1 and is still largely employed4 ,there are many forms of tint instruments1 but the one almost exclusively used here is that mentioned4 ,a full description of their construction and manipulation is given by ,tucker4#dc ,by the introduction of a third rotating nicol in front of the lens next to the lamp1 the sensitive tint at which the reading is made can be kept at a maximum delicacy4 ,these instruments are capable of rendering very reliable service1 especially in the hands of those who have a delicate perception of color4 ,they are inferior1 however1 to the shadow instruments in delicacy1 and are more trying to the eye of the observer4 ,the shadow instruments therefore1 especially those making use of an ordinary kerosene lamp1 have practically driven the tint polariscopes out of use4 ,the general arrangement of a tint instrument as modified by ,scheibler is shown in ,fig4 #cg4 ,illustration3 ,,figure #cg4 ,,tint ,,polariscope4 ,beginning on the right of the figures1 its optical parts are as follows3 ,a is a nicol which1 with the quartz plate ,b1 forms the apparatus for producing the light rose neutral tint4 ,the proper degree of rotation of these two parts is secured by means of the button ,l attached to the rod carrying the ratchet wheel as shown4 ,the polarizing nicol is at ,c1 and ,d is a quartz disk1 one-half of which is right-handed and the other left-handed4 ,at ,g is another quartz plate belonging to the analyzing part of the apparatus4 ,this1 together with the fixed quartz wedge ,f1 and the movable quartz wedge ,e1 constitute the compensating apparatus of the instrument whereby the deviation produced in the plane of polarized light by the solution in the tube is restored4 ,next to the compensating apparatus is the analyzing nicol which in this instrument is fixed in a certain place1 viz41 the zero of the scale4 ,the analyzer and the telescope for observing the field of vision are carried in the tube ,,hj4 ,the movable quartz wedge has a scale which is read with a telescope ,k1 provided with a mirror inclined at an angle of #de1 just over the scale and serving to illuminate it4 ,the quartz wedges are also provided with a movement by which the zero point of the scale can be adjusted4 ,a kerosene lamp with two flat wicks is the best source of illumination and the instrument should be used in a dark room and the light of the lamp1 save that which passes through the polariscope1 be suppressed by a shade4 ,the sensitive or transition tint is produced by that position of the regulating apparatus which gives a field of view of such a nature that a given small movement of the quartz compensating wedge gives the greatest contrast in color between the halves of the field of vision4 ,for most eyes a faint rose-purple tint1 as nearly colorless as possible1 possesses this quality4 ,a slight movement of the quartz wedge by means of the screw head ,m will1 with this tint1 produce on one side a faint green and on the other a pink color1 which are in strong contrast4 ,the neutral point is reached by so adjusting the quartz wedge as to give to both halves of the field the same faint rose-purple tint4 #gd4 ,the ,shadow ,polariscope for ,lamp ,light4--,this form of instrument is now in general use for saccharimetric purposes4 ,it possesses on the one hand1 the advantages of those instruments using monochromatic light1 and on the other1 the ease of manipulation possessed by the tint polariscopes4 ,it differs from the tint instrument in dispensing with the nicol and quartz plate used to regulate the sensitive tint1 and in having its polarizing nicol peculiarly constructed in harmony with the optical principles of the jellet-corny prism4 ,the more improved forms of the apparatus have a double quartz wedge compensation4 ,the two wedges are of opposite optical properties1 and serve to make the observations more accurate by mutual correction4 ,the optical arrangement of the different parts of such a polariscope is shown in the following figure4 ,the lenses for concentrating the rays of light and rendering them parallel are contained in the tube ,n4 ,at ,o is placed the modified polarizing nicol4 ,the two compensating quartz wedges are moved by the milled screw-heads ,,eg4 ,the rest of the optical apparatus is arranged as described under the tint polariscope4 ,for practical purposes1 only one of the wedges is employed1 but for all accurate work the readings should be made with both wedges and thus every possible source of error eliminated4 ,illustration3 ,,figure #ch4 ,,double ,,compensating ,,shadow ,,polariscope4 #ge4 ,the ,triple ,shadow ,instrument4--,when properly made1 all the instruments which have been mentioned1 are capable of giving accurate results if used in harmony with the directions given4 ,in the use of polariscopes having colored fields of vision a delicate sense of distinguishing between related tints is necessary to good work4 ,color-blind observers could not successfully use such apparatus4 ,in the shadow instruments it is only necessary to distinguish between the halves of a field of vision unequally illuminated and to reduce this inequality to zero4 ,a neutral field is thus secured of one intensity of illumination and of only one color1 usually yellow4 ,such a field of vision permits of the easy discrimination between the intensity of the coloration of its two halves1 and is consequently not trying to the eye of the observer1 and allows of great accuracy of discrimination4 ,this field of vision has lately been still further improved by dividing it into three parts instead of two4 ,an instrument of this kind1 ,fig4 #ci1 in use in this laboratory1 permits a delicacy of reading not possessed by any other instrument used for sugar analysis1 and approaching that of the standard ,landolt-,lippich apparatus1 used by us for research work and for determining the rotation of quartz plates and testing the accuracy of other polariscopes4 ,illustration3 ,,figure #ci4 ,,triple ,,shadow ,,polariscope4 ,the triple shadow is secured by interposing in front of the polarizing nicol two small nicols as indicated in ,fig4 #dj4 ,the end views in different positions of the polarizer are shown in the lower part of the diagrams4 ,illustration3 ,,figure #dj4 ,,apparatus ,,for ,,producing ,a ,,triple ,,shadow4 ,instead of the comparison of the intensity of the illumination being made on the halves of the field of vision it is made by comparing the segments of the halves with a central band1 which also changes in intensity synchronously with the two segments1 but in an opposite direction4 ,,the ,,analytical ,,process4 #gf4 ,general ,principles4--,having described the instruments chiefly employed in the optical examination of sugar solutions1 the next step is to apply them to the analytical work4 ,a common set of directions for use will be found applicable to all instruments with such modifications only as are required by peculiarities of construction4 ,with the best made instruments it is always advisable to have some method of controlling the accuracy of the observation4 ,the simplest way of doing this is to test the apparatus by standard quartz plates4 ,these plates are made from right-handed polarizing quartz crystal ground into plates of definite thickness and accurately tested by standard instruments4 ,theoretically such quartz plates deflect the plane of polarized light in a degree proportionate to their thickness1 but practically some small deviations from the rule are found4 ,with a source of light of the same tint1 and at a constant temperature1 such plates become a safe test for the accuracy of the graduation of polariscopes4 ,they are more convenient for use than pure sugar solutions of known strength which are the final standards in all disputed cases4 ,these quartz plates are conveniently mounted in tubes of the same size as those holding the sugar solution1 and thus fit accurately into the trough of the polariscope1 the optical axis of which passes through their center4 ,the quartz plate when used for setting the scale of a polariscope should be placed always in the same position4 ,in some plates slight differences of reading may be noticed on rotating the tubes holding them4 ,theoretically1 such differences should not exist1 but in practice they are sometimes found4 ,the temperature of observation should also be noted1 and if not that at which the value of the plate was fixed a proper correction should be made4 #gg4 ,setting the ,polariscope4--,while mention has been made of several forms of apparatus in the preceding paragraphs1 those in common use are limited to a very small number4 ,in this country quite a number of color instruments may still be found1 together with a few laurents1 and a constantly increasing number of shadow instruments for use with lamp light4 ,the following description of setting the polariscope is especially adapted to the last named instrument1 but the principles of adjustment are equally applicable to all4 ,the scale of the instrument is first so adjusted by means of the adjusting screws provided with each instrument1 as to bring the zero of the vernier and that of the scale exactly together4 ,the telescope or ocular is then adjusted until the sharp line separating the halves of the field of vision is brought into focus4 ,this being accomplished an observation tube filled with pure water is placed in the apparatus and the telescope again adjusted to bring the dividing line of the field into focus4 ,the beginner especially1 should repeatedly study this adjustment and be impressed with the fact that only in a sharply defined field are practical observations of any worth4 ,the importance of having all the lenses perfect and all the cover glasses without a flaw may be fully appreciated when it is remembered that the polarized ray1 already deprived of half its original luminous power1 must pass through several centimeters of crystallized calcium carbonate1 and half a dozen disks of glass and quartz1 and as many lenses before reaching the eye of the observer4 ,only with the greatest care and neatness is it possible to secure the required degree of illumination4 ,the zero point having been well studied and accurately adjusted1 the scale of the instrument may be tried with a series of quartz plates of known polarizing power at the temperature of the observation4 ,in the apparatus with double quartz wedge compensation1 it will be noticed that the marks on one scale are black and on the other red4 ,the black is the working and the red the control scale4 ,to operate this instrument1 the red scale is placed exactly at the zero point4 ,the black scale is also placed at zero1 and if the field of vision is not neutral1 it is made so by the micrometer screw with which the black scale is provided4 ,in a right-handed solution1 the red scale is left at zero and the black one moved to the right until neutrality in the field of vision is reached and the reading is taken4 ,the observation tube containing the sugar solution is taken out and the red scale moved until the field of vision is again neutral and the reading of the red scale taken4 ,the two readings should agree4 ,any failure in the agreement shows some fault either in adjusting the apparatus or in its construction1 or some error in manipulation4 ,the double compensating shadow instruments are more readily tested for accuracy in all parts of the scale than those of any other construction4 ,the two compensating wedges are cut with the greatest care1 one from a left-handed and the other from a right-handed perfectly homogeneous quartz crystal4 ,since faults in these wedges are due either to lack of parallelism of surface1 or of perpendicularity to the optical axis of the crystal1 and since these faults of crystallization or construction must be in a very limited degree common they would not coincide once in many thousand times in the two wedges4 ,this is easily shown by the theory of probabilities4 ,if1 therefore1 the two readings made at any point1 should not agree1 it must be due either to a fault in one of the wedges1 or to a fault in reading or a lack of adjustment1 as has been mentioned4 ,in such cases the readings should be retaken and the errors are usually easily discovered4 #gh4 ,control ,observation ,tube4--,instead of using quartz plates of known values for testing the accuracy of the scale1 an observation tube may be used1 the length of which can be varied at the pleasure of the observer4 ,the construction of a tube of this kind is shown in ,fig4 #dj4 ,the tube ,b is movable telescopically in ,a by means of the ratchet wheel shown4 ,it is closed at ,d water-tight by a glass disk4 ,the tube ,b fits as accurately into ,a as is possible to permit of free movement1 and any liquid which may infilter between its outer surface and the inner surface of ,a is prevented from gaining exit by the washer ,c1 which fits both tubes water-tight4 ,the ratchet which moves ,b in ,a carries a millimeter scale and vernier ,n whereby the exact thickness of the liquid solution between the surfaces of the glass disks ,d and ,e can be always determined4 ,illustration3 ,,figure #da4 ,,control ,,observation ,,tube4 ,by this device the length of liquid under observation can be accurately read to a tenth of a millimeter4 ,the cover glass ,e is held in position by any one of the devices in common use for this purpose in the case in question1 by a bayonet fastening4 ,the funnel ,t1 communicating directly with the interior of ,a1 serves to hold the solution1 there being always enough of it to fill the tube when ,d is removed to the maximum distance from ,c1 which is usually a little more than #bjj millimeters4 ,let the control tube be adjusted to #bjj millimeters and filled with a solution of pure sugar1 which reads #ajj per cent or degrees in a #bjj millimeter tube4 ,since the degree of rotation is1 other things being equal1 proportional to the length of the column of polarizing solution1 it follows that if the tube ,b be moved inward until the distance between ,d and ,c is #ajj millimeters1 the scale should read #ej or per cent4 ,by adjusting the length of the distance between ,b and ,c it is easily seen that every part of the scale can be accurately tested4 ,the tube should be filled by removing the funnel and closing the orifice with a screw cap which comes with the apparatus4 ,the cap ,e is then removed and the tube filled in the ordinary manner4 ,this precaution is practiced to avoid carrying air bubbles into the tube when filled directly through the funnel4 ,with a little care1 however1 this danger may be avoided1 or should air bubbles enter they can be easily removed by inclining the tube4 ,in case the solution used be not strictly pure it may still be employed for testing the scale4 ,suppose1 for instance1 that a solution made up in the usual way1 has been made from a sample containing only #ii4d per cent of sugar4 ,then in order to have this solution read #ajj on the scale the tube should be set at #bja4b millimeters1 according to the formula #bjj #ajj --------- #bja4b4 #ii4d ,by a similar calculation the position of the tube for reading any desired degree on the scale can be determined4 ,the importance of controlling all parts of the scale in compensating instruments is emphasized by the fact that a variation of only #j4jaf millimeter in the thickness of the compensating wedge will cause a change of one degree in the reading of the instrument4 #gi4 ,setting the ,polariscope with ,quartz ,plates4--,pure sugar is not always at the command of the analyst1 and it is more convenient practically to adjust the instrument by means of quartz plates1 the sugar values of which have been previously tested for the character of the light used4 ,assuming the homogeneity of a plate of quartz1 the degree of deflection which it imparts to a plane of polarized light depends on the quality of the light1 the thickness of the plate1 and the temperature4 ,in respect of the quality of light1 red polarized rays are least1 and violet most deflected4 ,the degree of rotation produced with any ray1 at a given temperature1 is directly proportional to the thickness of the plate4 ,temperature affects the rotating power of a quartz plate in a degree highly significant from a scientific point of view and not wholly negligible for practical purposes4 ,the rotating power of a quartz plate increases with the temperature and the variation may be determined by the formula given below3#dd ,the formula is applicable for temperatures between #j and #ajj4 ,its values are expressed in degrees of angular measure which can be converted into degrees of the sugar scale by appropriate factors3 ,formula4--a a7#a #j4jjjadft72 in which a polarization in angular degrees at #j1 t the temperature of observation and a the rotation desired4 ,example4--,a quartz plate which has an angular rotation of #cc at #j will have a rotation at #bj of #cc4jihcd4 a #cc7a #j4jjjadf #bj7 #cc4jihcd4 ,since in instruments using the ventzke scale one degree of the sugar scale is equal to #j4cdfg degree angular measure1 the sugar value of the quartz plate mentioned is equal to #ie4dg percent2 #cc4jihcd #j4cdfg #ie4dg4 ,the sugar value of this plate at #j is #ie4ah per cent2 #cc #j4cdfg #ie4ah4 #hj4 ,tables for ,correcting ,quartz ,plates4--,instead of calculating the variation in quartz plates for each temperature of observation1 it is recommended by the ,bureau of ,internal ,revenue of the ,treasury1 to use control quartz plates the values of which at any given temperature1 are found on a card which accompanies each one4#de ,the variations given1 are from temperatures between #aj and #ce4 ,three control plates are provided with each instrument used by the ,bureau1 for polarimetric work in the custom houses1 or in ascertaining bounties to be paid on the production of domestic sugars4 ,for example1 the case of a sugar which polarizes #hj4e may be cited4 ,one of the control plates nearest to this number1 is found to have at the temperature of observation1 a polarization of #ia4d1 the reading being made in each case at #be4 ,on consulting the card which accompanies the control plate1 it is seen that its value at the temperature mentioned1 is #ia4g4 ,the reading of the instrument is therefore too low by three-tenths of a degree1 and this quantity should be added to the observed polarization1 making it #hj4h4 ,in this method of correcting the reading for temperature1 it is assumed that the compensating wedges of the instrument1 are free of error at the points of observation4 ,the plates used for the purpose above1 are all standardized in the office of weights and measures of the ,coast and ,geodetic ,survey1 before delivery to the analysts4 #ha4 ,applicability of ,quartz ,plates4--,quartz plates which are correctly set for one instrument or kind of light1 should be equally accurate for the sugar scales of all instruments1 using the same sugar factor4 ,in other words a quartz plate which reads #ii on a scheibler color polariscope1 should give the same reading on the sugar scale of a shadow compensating or a monochromatic direct reading apparatus using #bf4jdh grams of sugar4 ,the most useful quartz plates for sugar analysis1 are those which give the readings at points between #hj and #if1 which cover the limits of ordinary commercial sugars4 ,for molasses the plates should read from #de to #ee4 ,for sugar juices of the cane and beet1 the most convenient graduation would be from #aj to #bj1 but plates of this value would be too thin for practical work and are not in use4 ,when quartz plates are to be used for control purposes1 they should be purchased from reliable manufacturers1 or better1 tested directly against pure sugar solutions by the observer4 ,in practice we have found quartz plates as a rule1 true to their markings4 #hb4 ,the ,sugar ,flask4--,sugar solutions are prepared for polarization in flasks graduated to hold fifty or one hundred cubic centimeters4 ,for scientific work a flask is marked to hold #ajj grams of distilled water at #d4 ,the weights are all to be reduced to a vacuum standard4 ,one flask having been marked in this way1 others may be compared directly therewith by means of pure mercury4 ,for this purpose the flasks must be perfectly dry and the mercury pure1 leaving no stain on the sides of the flask4 ,the glass must also be strong enough to undergo no change in shape from the weight of mercury used4 ,for sugar work the true #ajj gram flask is not usually employed1 but one graduated by weighing at #ag4e4 ,these flasks are graduated by first weighing them perfectly dry1 filling with distilled water and again weighing fifty and fifty-five1 or #ajj and #aaj grams of water at the temperature named4 ,since the volume of water at #ag4e is greater than at #d the sugar flask in ordinary use has a greater volume by about #j4be cubic centimeter than the true flask4 ,the observer should always secure a statement from the dealer in respect of the volume of the flask used in testing the scale of the polariscope purchased4 ,in the graduation of a flask in true cubic centimeters1 when brass weights are used it will be necessary to correct the weight of each gram of water by adding to it one milligram1 which is almost exactly the weight of the volume of air displaced by one gram of water in the circumstances named4 ,if the flask be first counterbalanced and it be desired to mark it at #ajj cubic centimeters the sum of the weights placed in the opposite pan should be #ajj - #j4ajj #ii4ijj grams4 ,while this is not a rigidly exact correction it will be sufficient for all practical purposes4 ,a liter of dry air weighs #a4bicff grams2 and #ajj cubic centimeters of water would therefore displace #j4abi gram of air4 ,but the brass weights also displace a volume of air which when deducted reduces the correction to be made for the water to nearly the one named4 ,for convenience in inverting sugar solutions the flasks used in practical work are graduated at fifty and fifty-five and #ajj and #aaj cubic centimeters respectively4 #hc4 ,preparing ,sugar ,solutions for ,polarization4--,if sugar samples were always pure the percentage of sugar in a given solution could be directly determined by immediate polarization4 ,such cases1 however1 are rarely met in practice4 ,in the majority of cases the sample is not only to be brought into solution but is also to be decolorized and rendered limpid by some one of the methods to be described4 ,a perfectly limpid liquid is of the highest importance to secure correct observations4 ,with a cloudy solution the field of vision is obscured1 the dividing line of the two halves1 or the double line in the triple field1 becomes blurred or invisible and the intensity of illumination is diminished4 ,a colored liquid which is bright is far more easy to polarize than a colorless liquid which is turbid4 ,in fact1 it is only rarely in sugar work that samples will be found which require any special decolorizing treatment other than that which is received in applying the reagents which serve to make the solutions limpid4 ,in the following paragraphs the approved methods of clarifying sugar solutions preparatory to observation in the polariscope will be described4 #hd4 ,alumina ,cream4--,the hydrate of alumina1 commonly known as alumina cream1 is always to be preferred as a clarifying agent in all cases where it can be successfully applied4#df ,it is a substance that acts wholly in a mechanical way and therefore leaves the sugars in solution unchanged1 carrying out only suspended matters4 ,in the preparation of this reagent a solution of alum is treated with ammonia in slight excess1 the aluminum hydroxid produced washed on a filter or by decantation until neutral in reaction4 ,the hydroxid is suspended in pure water in proportions to produce a creamy liquid4 ,although apparently very bulky1 the actual space occupied by the amount of dry hydroxid added in a few cubic centimeters is so small as to produce no disturbing effect of importance on the volume of the sugar solution4 ,the cream thus prepared is shaken just before using and from one to five cubic centimeters of it1 according to the degree of turbidity of the saccharine solution1 are added before the volume in the flask is completed to the mark4 ,after filling the flask to the mark the ball of the thumb is placed over the mouth and the contents well shaken and allowed to stand for a few moments before filtering4 ,the alumina cream is well suited to use with solutions of commercial sugars of not too low a grade and of most honeys and high grade sirups4 ,it is usually not powerful enough to clarify beet and cane juices1 molasses and massecuites4 #he4 ,basic ,lead ,acetate4--,a solution of basic lead acetate is an invaluable aid to the sugar analyst in the preparation of samples for polarimetric observation4 ,it acts as a clarifying agent by throwing out of solution certain organic compounds and by uniting with the organic acids in solution forms an additional quantity of precipitate1 and these precipitates act also mechanically in removing suspended matters from solution4 ,the action of this reagent is therefore much more vigorous than that of alumina cream4 ,coloring matters are often precipitated and removed by treatment with lead acetate4 ,it happens therefore that there are few samples of saccharine bodies whose solutions cannot be sufficiently clarified by lead acetate to permit of polarimetric observation4 ,the reagent is most frequently employed of the following strength3#dg ,boil for half an hour in one and a half liters of water #dfd grams of lead acetate and #bfd grams of litharge with frequent stirring4 ,when cool1 dilute with water to two liters1 allow to stand until clear1 and decant the solution4 ,the specific gravity of this solution is about #a4bfg4 ,in a solution of basic lead acetate of unknown strength the percentage of lead acetate may be determined from its specific gravity by the following table3#dh ,,percentage ,,of ,,lead ,,acetate ,,corresponding ,,to ,,different ,,specific ,,gravities ,,at #ae4 ,percentage of ,percentage of ,specific gravity4 lead acetate4 ,specific gravity4 lead acetate4 #a4jabg #b #a4bjdj #bh #a4jbee #d #a4bbaa #cj #a4jchf #f #a4bcie #cb #a4jebj #h #a4begi #cd #a4jfed #aj #a4bgfh #cf #a4jgif #ab #a4biff #ch #a4jici #ad #a4cafc #dj #a4ajhd #af #a4ccgf #db #a4abcd #ah #a4cehh #dd #a4achd #bj #a4chaj #df #a4aedd #bb #a4djda #dh #a4agjd #bd #a4dbga #ej #a4ahfi #bf #hf4 ,errors ,due to use of ,lead ,solutions4--,in the use of lead solutions there is danger of errors intruding into the results of the work4 ,these errors are due to various sources4 ,lead subacetate solution1 when used with low grade products1 or sugar juices1 or sirups from beets and canes1 precipitates albuminous matters and also the organic acids present4 ,the bulk occupied by these combined precipitates is often of considerable magnitude1 so that on completing the volume in the flask the actual sugar solution present is less than indicated4 ,the resulting condensation tends to give too high a polarimetric reading4 ,with purer samples this error is of no consequence1 but especially with low grade sirups and molasses it is a disturbing factor1 which must be considered4 ,one of the best methods of correcting it has been proposed by ,scheibler4#di ,to #ajj cubic centimeters of a solution of the sample1 ten of lead solution are added1 and after shaking and filtering the polarimetric reading is taken4 ,another quantity of #ajj cubic centimeters of the solution with ten of lead is diluted to #bbj cubic centimeters1 shaken1 filtered1 and polarized4 ,double the second reading1 subtract it from the first1 multiply the difference by #b4b1 and deduct the product from the first reading4 ,the remainder is the correct polarization4 ,the process just described is for the usual work with beet juices and sirups4 ,for cane juices measured by the graduated pipette1 hereafter to be described1 and for weighed samples of molasses and massecuites1 the following method of calculation is pursued4#ej ,to the sample dissolved in water1 add a measured portion of the lead subacetate solution1 make its volume #ajj cubic centimeters and observe the polarimetric reading4 ,prepare a second solution in the same way and make the volume double that of the first and again take the polarimetric reading4 ,multiply the second reading by two1 subtract the product from the first reading and multiply the remainder by two1 and subtract the product from the first reading4 ,example4--,first polarization #cj4j ,second polarization #ad4i ,then #cj - 7#b #ad4i #bi4h7 #j4b #j4b #b #j4d and #cj - #j4d #bi4f ,the corrected reading therefore shows that the sample contained #bi4f per cent of sugar4 #hg4 ,error ,due to ,action of ,lead ,subacetate on ,levulose4--,in the use of lead subacetate solution not only is there danger of error due to the causes just described1 but also to a more serious one1 arising from the chemical interaction of the clarifying agent and levulose4#ea ,lead subacetate forms a chemical union with levulose and the resulting compound has a different rotatory power from the left-handed sugar in an uncombined state4 ,by adding a sufficient quantity of subacetate solution1 the left-handed rotation of levulose may be greatly diminished if not entirely destroyed4 ,in this case the dextrose1 which with levulose forms inverted sugar1 serves to increase the apparent right rotation due to the sucrose in solution4 ,the reading of the scale is therefore higher than would be given by the sucrose alone4 ,if the lead subacetate could be added in just the proportion to make the invert sugar neutral to polarized light1 its use would render the analysis more accurate2 but such a case could only arise accidentally4 ,to correct the error1 after clarification1 the compound of levulose and lead may be decomposed by the addition of acetic acid according to the method of ,spencer4 ,in this case the true content of sucrose can only be obtained by the method of inversion proposed by ,clerget1 which will be described in another paragraph4 #hh4 ,clarification with ,mercuric ,compounds4--,where the disturbing bodies in a solution are chiefly of an albuminoid nature1 one of the best methods of securing clarification is by the use of a solution containing an acid mercuric compound4#eb ,in the case of milk this method is to be preferred to all others4 ,albuminoid bodies themselves1 have the property of deflecting the plane of polarization1 as a rule1 to the left1 and therefore1 should be completely removed from solutions containing right-handed sugars such as lactose4 ,for this purpose the mercuric compound is more efficient than any other4 ,it is prepared and used as follows4#ec ,dissolve mercury in double its weight of strong nitric acid and dilute the solution with an equal volume of water4 ,one cubic centimeter of this solution is sufficient to clarify fifty times its volume of milk4 #hi4 ,decolorization by ,means of ,bone-,black4--,where the means already described fail to make a solution sufficiently colorless to permit of the passage of a ray of polarized light1 recourse should be had to a decolorizing agent4 ,the most efficient of these is bone-black4 ,for laboratory work it is finely ground and should be dry if added to an already measured solution4 ,when moist it should be added to the flask before the volume is completed1 and a correction made for the volume of the dry char employed4 ,bone-black has the power of absorbing a certain quantity of sugar1 and for this reason as little of it should be employed as is sufficient to secure the end in view4 ,if not more than one gram of the char be used for #ajj cubic centimeters of solution1 the error is not important commercially4 ,the error may be avoided by placing the char on the filter and rejecting the first half of the filtered solution4 ,the char becomes saturated with the first portion of the solution1 and does not absorb any sugar from the second4 ,this method1 however1 does not secure so complete a decolorization as is effected by adding the black directly to the solution and allowing to stand for some time with frequent shaking4 #ij4 ,remarks on ,analytical ,process4--,since large weights of sugar are taken for polarization1 a balance which will weigh accurately to one milligram may be used4 ,in commercial work the weighing is made in a counterpoised dish with a prominent lip1 by means of which the sample can be directed into the mouth of the flask after partial solution4 ,where the air in the working room is still1 an uncovered balance is most convenient4 ,with a little practice the analyst will be able to dissolve and transfer the sample from the dish to the flask without danger of loss4 ,the source of light used in polarizing should be in another room1 and admitted by a circular opening in the partition4 ,in a close polarizing room1 which results from the darkening of the windows1 the temperature will rapidly rise if a lamp be present1 endangering notably the accuracy of the work1 and also interfering with the comfort of the observer4 ,the greatest neatness must be practiced in all stages of the work1 and especially the trough of the polariscope must be kept from injury which may arise from the leaking of the observation tubes4 ,dust and dirt of all kinds must be carefully excluded from the lenses1 prisms1 wedges and plates of the instrument4 #ia4 ,determination of ,sucrose by ,inversion4--,in the foregoing paragraphs directions have been given for the estimation of sugar 7sucrose7 by its optical properties4 ,it has been assumed so far1 that no other disturbing bodies have been present1 save those which could be removed by the clarifying agents described4 ,the case is different when two or more sugars are present1 each of which has a specific relation to polarized light4 ,in such cases some method must be used for the optical determination of sucrose1 which is independent of the influence of the other polarizing bodies1 or else recourse must be had to other methods of analysis4 ,the conversion of the sucrose present into invert sugar by the action of an acid or a ferment1 affords an opportunity for the estimation of sucrose in mixed sugars1 by purely optical methods4 ,this process rests upon the principle that by the action of a dilute acid for a short time1 or of a ferment for a long time1 the sucrose is completely changed1 while other sugars present are not sensibly affected4 ,neither of these assumptions is rigidly correct but each is practically applicable4 ,the sucrose by this process of hydrolysis is converted into an equal mixture of levulose and dextrose4 ,the former1 at room temperatures1 has the higher specific rotating power1 and the deflection of the plane of polarization in a solution of inverted sugar is therefore to the left4 ,the levorotatory power of invert sugar varies with the temperature1 and this arises from the optical properties of the levulose4 ,the influence of temperature on the rotating power of other sugars1 is not imperceptible in all cases1 but in practice is negligible4 ,this method of analysis is invaluable in control work in factories1 in the customs and in agricultural laboratories4 ,since the rotating power of levulose diminishes as the temperature rises1 an accurate thermometric observation must accompany each polarimetric reading4 ,at about #hh the rotatory powers of dextrose and levulose are equal1 and a solution of pure invert sugar examined at that degree1 is found to be neutral to polarized light4 #ib4 ,clerget's ,method of ,inversion4--,the classical method of ,clerget for the determination of cane sugar by double polarization before and after inversion1 was first described in a memoir presented to the ,society of ,encouragement for ,national ,industry on the #adth of ,october1 #ahdf4 ,the following description of the original method is taken from a reprint of the proceedings of that ,society1 dated ,nov4 #ahdf3 ,clerget points out first the observation of ,mitscherlich regarding the influence of temperature on the rotatory power of invert sugar1 and calls attention to the detailed experiments he has made which resulted in the determination of the laws of the variation4 ,from these studies he was able to construct a table of corrections1 applicable in the analysis of all saccharine substances in which the cane sugar is polarized before and after inversion4 ,the basis of the law rests upon the observation that a solution of pure sugar1 polarizing #ajj on the sugar scale1 before inversion1 will polarize #dd to the left after inversion at a temperature of zero4 ,the quantity of sugar operated upon by ,clerget amounted to #af4dga grams in #ajj cubic centimeters of liquid4 ,on the instrument employed by him this quantity of sugar in #ajj cubic centimeters gave a reading of #ajj to the right on the sugar scale when contained in a tube twenty centimeters in length4 ,the process of inversion carried on by ,clerget is as follows3 ,the sugar solution is placed in a flask1 marked on the neck at #ajj and #aaj cubic centimeters2 or if smaller quantities are used1 in a flask marked on the neck at fifty and fifty-five cubic centimeters4 ,the flask is filled with the sugar solution to the first mark and then a sufficient quantity of strong hydrochloric acid added to bring the volume of the liquid to the second mark4 ,the mouth of the flask is then closed with the thumb and its contents thoroughly mixed by shaking4 ,a thermometer is placed in the flask which is set in a water-bath in such a way that the water comes just above the level of the liquid in the neck of the flask4 ,the water is heated in such a manner as to bring the temperature of the contents of the flask1 as determined by the thermometer1 exactly to #fh and at such a rate as to require fifteen minutes to reach this result4 ,at the end of fifteen minutes the temperature having reached #fh the flask is removed and placed at once in another water-bath at the temperature of the room1 to which temperature the contents of the flask are cooled as rapidly as possible4 ,to make the polarimetric observation a tube twenty-two centimeters in length is filled with the inverted sugar solution by means of a tubulure in its center1 which serves not only the purpose of filling the tube but also afterwards to carry the thermometer1 by means of which the temperature of observation can be taken4 ,if the sugar solution be turbid1 or contain any lead chlorid due to the previous use of basic lead acetate in clarification1 it should be filtered before being introduced into the observation tube4 ,this tube being one-tenth longer than the original compensates for the dilution caused by the addition of the hydrochloric acid in inversion4 ,when reading1 the bulb of the thermometer should be withdrawn far enough to permit the free passage of the ray of light and the exact temperature of the solution noted4 ,the above outline of ,clerget's method of inversion is given in order that the analyst may compare it with any of the variations which he may find in other works4 ,the chief points to which attention is called1 are1 first1 the fact that only a little over sixteen grams of sugar are used for ten cubic centimeters of strong hydrochloric acid1 and second1 that the time of heating is exactly fifteen minutes1 during which time the contents of the flask should be raised from room temperature to exactly #fh4 ,from the above it is seen that the process of ,clerget1 as originally described1 can be applied directly to all instruments1 using approximately sixteen grams of sugar in #ajj cubic centimeters4 ,experience has also shown that even when larger quantities of sugar are employed1 as for instance1 approximately twenty-six grams1 the inversion is effected with practical completeness in the same circumstances4 ,it is advised1 therefore1 that in all analytical processes1 in which cane sugar is to be determined by the process of inversion with an acid1 the original directions of ,clerget be followed as strictly as possible4 ,experience has shown that no one of the variations proposed for ,clerget's original method has any practical advantage and the analyst is especially cautioned against those methods of inversion in which the temperature is continued at #fh for fifteen minutes or in which it is allowed to go above that degree4 #ic4 ,influence of ,strength of ,solution and ,time of ,heating on the ,inversion of ,sucrose4--,as has been intimated1 the strength of a sugar solution and the time of heating with hydrochloric acid are factors that must be considered in determining a formula for the calculation of sucrose by inversion4 ,the ,clerget formula holds good only for the conditions specified and these conditions must be rigidly adhered to in order to secure the proper results4 ,this matter has been thoroughly studied by ,borntrger1 who also gives a nearly complete bibliography of the subject4#ed ,as a result of his investigations it seems well established that the original ,clerget formula is practically correct for the conditions indicated1 ,borntrger modifying it only by substituting in the formula #adc4ff for #add4 ,this is so nearly the same as the ,clerget factor that it is not advisable to substitute it therefor4 ,if1 however1 the inverted sugar solution be diluted to double its volume before polarization the factor proposed by ,landolt1 viz41 #adb4d1 gives more nearly accurate results4 ,if the hydrochloric acid be neutralized before polarization by an alkaline body1 the character of the salt which is formed also influences1 to a greater or less extent1 the specific rotatory power of the solution4 ,hydrochloric acid itself also influences the rotation to a certain degree4#ee #id4 ,calculation of ,results4--,the percentage of sucrose in a solution which has been polarized before and after inversion is calculated by an appropriate formula from the data obtained or is taken directly from tables4 ,these tables are too long to insert here1 and in point of fact the calculation can be made from the formula almost as quickly as the result can be taken from a table4 ,two factors are commonly used in the calculations1 one based on the supposition that a sugar solution polarizing #ajj to the right will1 after inversion1 give a reading of #dd to the left1 at zero temperature4 ,in the second formula in common use the polarization to the left in the circumstances mentioned above is assumed to be #db4d1 a number reached by ,landolt after a long series of experiments4#ef ,the principle of the calculation of the percentage of sucrose is based upon the original observation of ,clerget to the effect that the algebraic difference of the two readings1 divided by #add1 less half of the temperature1 will give the percentage of sucrose desired4 ,the formula by which this is obtained is a - b ,s -----------4 ,k - t ---- #b ,in this formula a is the polarization on the sugar scale before inversion1 b the polarization after inversion1 ,k the constant representing the algebraic difference of the two polarizations of pure sugar at #j and t the temperature of the observation4 ,to ,k may be assigned the values #add or #adb4d1 the one in more common use4 ,in case the polarization1 after inversion1 is to the left1 which is more commonly the case1 the sum of the two readings is taken for a - 7-b7 a b2 when both polarizations are to the right or left the difference is taken4 ,s is the percentage of sucrose desired4 ,example4--,let the polarization before inversion be #ie and after inversion -#bf and the temperature #bj #ie #bf ,then ,s -------- #aba #acd #ij4f4 #add - #aj ,substituting the value #adb4d for ,k1 the result of the calculation is #ia4d4 ,in high grade sugars1 therefore1 the difference in the results secured by taking the two values of ,k amounts to about #a per cent of sucrose4 ,for a further discussion of the theory and practice of inversion the reader is referred to the articles of ,herles1 ,herzfeld1 and ,wohl4#eg #ie4 ,method ,of ,lindet4--,courtonne recommends the method of ,lindet for securing the inversion instead of the method of ,clerget4#eh ,modified by ,courtonne1 the method is as follows3 ,make two or three times the normal weight of sugar dissolved in water to a volume of #bjj or #cjj cubic centimeters1 as the case may be4 ,after thoroughly mixing proceed as follows3 ,first1 to ,obtain the ,polarization ,direct4--,place fifty or #ajj cubic centimeters of the prepared solution in a flask marked at fifty and fifty-five or at #ajj and #aaj cubic centimeters1 add a sufficient quantity of lead acetate to secure a complete clarification1 make the volume to fifty-five or #aaj cubic centimeters1 shake thoroughly1 filter1 and polarize in a #bbj millimeter tube4 ,second1 to ,obtain the ,rotation after ,inversion4--,place twenty cubic centimeters of the original solution1 in a flask marked at fifty cubic centimeters1 containing five grams of powdered zinc4 ,the flask should be placed in boiling water4 ,add1 little by little so as to avoid a too rapid evolution of hydrogen1 ten cubic centimeters of hydrochloric acid made of equal parts of the strongest acid and water4 ,after the operation is terminated1 cool to the temperature of the room1 make the volume to fifty cubic centimeters1 polarize1 and determine the rotation4 ,the volume occupied by the zinc which is not dissolved1 will be about one-half cubic centimeter1 hence the deviation should be multiplied by the factor #b4dge in order to get the true deviation which would have been produced by the pure liquor4 ,we have then3 ,a the deviation direct4 ,b the deviation after inversion4 ,c the algebraic difference of the deviations4 ,the amount of sucrose1 therefore1 would be calculated by the formula of ,creydt1#ei ,c - #j4dic;,a ,x --------------2 #j4hbg for raffinose the formula would be ,a - ,s ,y ---------1 #a4eg in which ,s is the deviation due to the sucrose present4 ,the solutions inverted in the manner described are absolutely colorless4 ,there is no need of employing bone-black to secure the saccharimetric reading nor does it present any uncertainty4 ,it is thought by ,courtonne that this method will soon take the place of the method of ,clerget on account of the advantages above mentioned4 ,the method will be somewhat improved by adopting the following suggestions3 #a4 ,instead of allowing any arbitrary number for the volume of the undissolved zinc1 decant the liquid1 after inversion1 into another flask and wash repeatedly with hot water until all trace of sugar is removed from the flask in which the inversion took place4 #b4 ,instead of polarizing in a #bjj millimeter tube make the observation in a #ejj millimeter tube1 which will permit of the reading being made without any correction whatever4 #if4 ,inversion by ,means of ,invertase4--,instead of using acids for the inversion of cane sugar the hydrolysis can be easily effected by means of a ferment derived from yeast4 ,a complete history of the literature and characteristics of this ferment1 together with a study of its properties and the various methods of preparing it1 has been given by ,o',sullivan and ,tompson4#fj ,in the preparation of invertase1 the method found most effective is the following3 ,the yeast is allowed to liquify for at least a month in a fairly warm room without stirring4 ,at the end of this time the surface is removed and any supernatant liquid poured away4 ,the lower sedimentary part is thrown on a quick-acting filter and allowed to drain for two days4 ,to the filtrate1 alcohol of specific gravity #j4hg is gradually added to the extent of one and a half times its volume1 with continued and vigorous stirring4 ,the process of adding the alcohol and stirring should require about half an hour1 after which the mixture is allowed to stand for twenty-four hours to allow the precipitated invertase to settle4 ,the supernatant liquid is poured away and the precipitate washed several times on successive days by decantation with alcohol of #j4ib specific gravity4 ,when the washings become nearly colorless the precipitate is thrown on a filter1 allowed to drain1 and immediately removed and mixed with a large bulk of alcohol of #j4ib specific gravity4 ,the precipitate is again collected1 mixed thoroughly with its own bulk of water1 and some alcohol of #j4ig specific gravity1 allowed to stand for a few hours and thrown on a filter4 ,the filtrate contains the invertase4 #ig4 ,determination of ,activity of ,invertase4--,the activity of a solution of invertase1 prepared as above1 is measured by the number of minutes required for it to reduce to zero the optical power of a solution of #ajj times its weight of cane sugar at a temperature of #ae4e4 ,in order to facilitate the action of the invertase1 a trace of sulfuric acid is added to the solution4 ,the manipulation is as follows3 ,fifty grams of sucrose are dissolved in water and made to a volume of nearly a quarter of a liter and placed in a bath maintained at #ae4e4 ,half a gram of the invertase is added1 the time noted1 the solution immediately made up to a quarter of a liter and well shaken4 ,the contents of the flask are poured rapidly into five beakers2 the actual quantity in each beaker is not necessarily the same4 ,to each of these beakers1 in succession1 are added the following amounts of decinormal sulfuric acid1 viz41 one-tenth1 three-tenths1 six-tenths1 one1 and one and four-tenths cubic centimeters4 ,after an hour a small quantity of the solution is taken from beaker ,no4 #c and the reaction of the invertase stopped by adding a few drops of strong potassium hydroxid and the time of adding this reagent noted4 ,this solution is then read in the polariscope and the percentage of sugar inverted is calculated from the formula ,c,h,o ,h,o ,c,h,o ,c,h,o4 ,the calculation of the amount of cane sugar inverted is based on the formula1 7#ch4d - d7 #j4eah p4 ,in this formula d equals the divisions of the sugar scale read on the polariscope2 p the percentage of cane sugar inverted2 #ch4d the reading on the sugar scale of the original sugar solution and #ea4h the total number of divisions of the cane sugar scale that the polariscope reading would fall through if all the sugar were inverted4 ,the observation tubes used in the polarization are only #ajj millimeters in length4 ,after stopping the action of the invertase with potassium hydroxid the solution is allowed to stand for some time before polarization inasmuch as the dextrose formed appears to assume the state of birotation and some time is required for it to reach its normal rotatory power4 ,if the invertase be used in the alcoholic solution a sufficient quantity should be added to be equivalent to #j4ja of the sucrose present4 ,the time which the contents of beaker ,no4 #c will take to reach optical activity is calculated in a manner described by ,o',sullivan and ,tompson1 but too long to be inserted here4#fa ,the five beakers mentioned above are examined in succession and the amount of sulfuric acid best suited to the maximum inversion thus determined4 ,this quantity is then used in subsequent hydrolyses with the given sample of invertase4 ,the action of invertase on sucrose is very rapid at the first and becomes very much slower towards the end4 ,at a temperature of #ae4e it is advisable to let the solution stand for forty-eight hours in order to be sure that complete inversion has taken place4 ,for this reason the method by inversion by means of invertase is one of no great practical importance1 but it may often be useful to the analyst when the employment of an acid is inadmissible4 #ih4 ,inversion by ,yeast4--,owing to the difficulty of preparing invertase1 ,o',sullivan and ,thompson#fb propose to use yeast as the hydrolytic agent1 as first suggested by ,kjeldahl4 ,it is shown that in the use of yeast it is not necessary to employ thymol or any other antiseptic4 ,the method of procedure is as follows3 ,the cane sugar solution of usual strength should not be alkaline1 but1 if possible1 should be exactly neutral4 ,if there be any ferment suspected1 the temperature should be momentarily raised to #hj to destroy its activity4 ,the polariscopic reading of the solution is then taken at #ae4e and the amount of copper reduced by the solution should also be determined4 ,fifty cubic centimeters of the solution are poured into a beaker and raised to a temperature of #ee in a constant temperature bath4 ,some brewers yeast amounting to about one-tenth of the total amount of sugar to be inverted1 pressed in a towel1 is thrown into the hot solution and the whole stirred until mixture is complete4 ,the solution is left for four hours in the water-bath1 at the end of this time it is cooled to #ae4e1 a little freshly precipitated aluminum hydroxid added1 and the volume made to #ajj cubic centimeters4 ,a portion of this solution is filtered and its polariscopic reading observed4 ,the solution is then left till the next day1 when another polariscopic reading is taken in order to prove that inversion is complete4 ,the copper reducing power is also determined4 ,the method of calculating the results is the same as when invertase is used4 ,the following formulas are employed4 a the number of divisions indicated by the polariscopic reading for a #bjj millimeter tube3 a the same number after inversion3 m the number of the divisions of the polariscopic scale which #bjj millimeters of the sugar solution containing one gram of cane sugar per #ajj1 alter at #ae4e on being inverted3 ,in the case of the ventzke polarimeter scale1 one gram of cane sugar in #ajj cubic centimeters1 indicates #c4hd divisions and after inversion it gives -#a4cd div4 ,in experiments of this kind1 therefore1 m #e4ah4 ,p the weight of cane sugar present in #ajj cubic centimeters of the original solution3 ,the formula employed then is a - #b;a ,p -----------4 m ,for the copper reduction data the following are used3 ,g the weight of #ajj cubic centimeters of the original solution3 ,g2 the same for the inverted solution3 ,allowance must be made here both for the dilution and for the #e per cent increase of the inverted sugar1 but the latter number is so small that it need not be calculated accurately4 w the weight of the original solution used for the estimation3 w the same factor for the inverted solution3 k the weight of cupric oxid reduced by w3 k the same factor for w3 p the weight of cane sugar present in #ajj cubic centimeters of the original solution3 ,the formula to be employed then is ,g k ,g k p #j4dcjh7b ------ - -----74 w w ,this method has been applied to the estimation of cane sugar in molasses1 apple juices and other substances4 ,it is recommended by the authors as a simple and accurate means of estimating sucrose in all solutions containing it4 ,the methods of making the copper reductions will be given hereafter4 #ii4 ,application of the ,process4--,in practice the process of inversion is used chiefly in the analysis of molasses and low grade massecuites4 ,in approximately pure sugars the direct polarization is sufficiently accurate for all practical purposes4 ,in molasses resulting from the manufacture of beet sugar are often found considerable quantities of raffinose1 and the inversion process has been adapted to that character of samples4 ,in molasses1 in sugar cane factories1 the disturbing factors are chiefly invert sugars and gums4 ,the processes used for molasses will be given in another paragraph4 ,in certain determinations of lactose the process of inversion is also practiced1 but in this case the lactose is converted into dextrose and galactose1 and the factors of calculation are altogether different4 ,the process has also been adapted by ,mc,elroy and ,bigelow to the determination of sucrose in presence of lactose1 and this method will be described further on4 ,in general the process of inversion is applicable to the determination of sucrose in all mixtures of other optically active bodies1 which are not affected by the methods of inversion employed4 #ajj4 ,determination of ,sucrose and ,raffinose4--,raffinose is a sugar which often occurs in beets1 and is found chiefly in the molasses after the chief part of the sucrose has been removed by crystallization4 ,it is also found in many seeds1 notably in those of the cotton plant4 ,in a pure solution of sucrose and raffinose1 both sugars may be determined by the inversion method of ,creydt4#fc ,the inversion is effected by means of hydrochloric acid in the manner described by ,clerget4 ,the following formulas are calculated for a temperature of observation of #bj1 and the readings should be made as near that temperature as possible4 ,c - #j4dic;,a 7#a7 ,s -------------- #j4hbg ,a - ,s #f 7#b7 ,r --------- #a4jag;,a - ------4 #a4eg #a4bih ,in these formulas ,s and ,r are the respective per cents of sucrose and raffinose desired1 ,a the polarization in sugar degrees before inversion1 ,b the polarization after inversion read at #bj1 and ,c is the algebraic difference between ,a and ,b4 ,it must be understood that these formulas are applicable only to a solution containing no other optically active substances1 save sucrose and raffinose4 #aja4 ,specific ,rotatory ,power4--,in order to compare among themselves the rotations produced on a plane of polarized light by different optically active bodies in solution1 it is convenient to refer them all to an assumed standard4 ,the degree of rotation which the body would show in this condition1 is found by calculation1 since1 in reality1 the conditions assumed are never found in practice4 ,in the case of sugars and other optically active bodies1 the standard of comparison is called the specific rotatory power4 ,this factor in any given case1 is the angular rotation which would be produced by any given substance in a pure anhydrous state if it were one decimeter in length and of a specific gravity equal to water4 ,these are conditions which evidently do not exist in the case of sugars1 since crystalline sugar particles have no polarizing power1 and it would be impossible to pass a ray of light through an amorphous sugar column of the length specified4 ,the specific rotatory power is therefore to be regarded as a purely theoretical factor1 calculated from the actual data obtained by the examination of the solution of any given substance4 ,if the length of the observation tube in decimeters be represented by l1 the percentage of the polarizing body in #ajj grams by p1 and the specific gravity of the solution by d1 and the observed angle of rotation by a1 then the factor is calculated from the formula3 a4 #ajj a,dj ---------------4 p4 d4 l4 ,the symbols ,dj refer to the character of light employed1 ,d indicating the monochromatic sodium flame1 and j the transition tint from white light4 ,if the weight of the polarizing body c be given or known for #ajj cubic centimeters of the solution the formula becomes a4 #ajj a,dj ----------4 c4 l4 ,the latter formula is the one easier of application since it is only necessary in applying it to dissolve a given weight of the active body in an appropriate solvent and to complete the volume of the solution exactly to #ajj cubic centimeters4 ,it is therefore unnecessary in this case to determine the specific gravity4 #ajb4 ,formulas for ,calculating ,specific ,rotatory ,power4--,in order to determine the specific rotatory power 7gyrodynat#fd7 of a given substance it is necessary to know the specific gravity and percentage composition or concentration of its solution1 and to examine it with monochromatic polarized light in an instrument by which the angular rotation can be measured4 ,the gyrodynat of any body changes with its degree of concentration1 in some cases with the temperature1 and always with the color of the light4 ,with the red rays the gyrodynat is least and itprogressively increases as the violet end of the spectrum is approached4 ,in practice the yellow ray of the spectrum has been found most convenient for use1 and in the case of sugars the gyrodynat is always expressed either in terms of this ray or if made with color compensating instruments in terms of the sensitive or transition tint4 ,in the one case the symbol used is 7a7,d and in the other 7a7j4 ,from this statement it follows that 7a7,d is always numerically less than 7a7j4 ,unless otherwise specified the gyrodynat of a body is to be considered as determined by yellow monochromatic light1 and therefore corresponds to a,d4#fe #ajc4 ,variations in ,specific ,rotatory ,power4--,the gyrodynat of any optically active body varies with the nature of the solvent1 the strength of the solution1 and the temperature4#ff ,since water is the only solvent of importance in determining the gyrodynat of sugars it will not be necessary here to discuss the influence of the nature of the solvent4 ,in respect of the strength of the solution it has been established that in the case of cane sugar the gyrodynat decreases while with dextrose it increases with the degree of concentration4 ,the influence of temperature on the gyrodynat of common sugars is not of great importance save in the case of levulose1 where it is the most important factor1 the gyrodynat rapidly increasing as the temperature falls4 ,it is of course understood that the above remarks do not apply to the increase or decrease in the volume of a solution at changed temperatures4 ,this influence of temperature is universally proportional to the change of volume in all cases1 and this volumetric change is completely eliminated when the polarizations are made at the temperatures at which the solutions are completed to standard volumes4 #ajd4 ,gyrodynatic ,data for ,common ,sugars4--,in the case of cane sugar the gyrodynat for twenty-five grams of sugar in #ajj grams of solution at #bj is a,d #ff4cg4 ,this is about the degree of concentration of the solutions employed in the shadow lamplight polariscopes4 ,for seventeen grams of sugar in #ajj grams of solution the number is a,d #ff4di4 ,this is approximately the degree of concentration for the laurent instrument4 ,for any degree of concentration according to ,tollens the gyrodynat may be computed by the following formula3 a,d #ff4chf #j4jaejcep - #j4jjjcihfp1 in which p is the number of grams of sugar in #ajj grams of the solution4#fg ,in the table constructed by ,schmitt the data obtained are as follows3 ,in #ajj parts by weight ,specific ,rotation a of solution4 gravity ,concentration for #ajj mm4 ,sugar p4 ,water q4 at #bj ,c4 d4 c pd4 at #bj ,c4 a,d4 #fd4igge #ce4jbbe #a4cafej #he4edcb #ef4acd #fe4fbj #ed4ifdc #de4jceg #a4begcb #fi4ajgf #de4ecc #fe4iai #ci4iggg #fj4jbbc #a4agffd #dg4jcib #ca4agd #ff4bgb #be4jjai #gd4iiha #a4ajcfg #bg4eich #ah4cce #ff4dda #af4iibf #hc4jjgd #a4jfggg #ah4addb #ab4jfd #ff4dhh #i4iiig #ij4jjjc #a4jchbj #aj4chag #f4iab #ff4egd #d4iige #ie4jjbe #a4jaghg #e4jhfh #c4chh #ff4fji #a4iihf #ih4jjad #a4jjfjg #b4jajg #a4cdc #ff4hjb #aje4 ,bi-,rotation4--,some sugars in fresh solution show a gyrodynat much higher than the normal1 sometimes lower4 ,the former phenomenon is called bi- the latter semi-rotation4 ,dextrose shows birotation in a marked degree1 also maltose and lactose4 ,after standing for a few hours1 or immediately on boiling1 solutions of these sugars assume their normal state of rotation4 ,the addition of a small quantity of ammonia also causes the birotation to disappear4#fh ,this phenomenon is doubtless due to a certain molecular taxis1 which remains after solution is apparently complete4 ,the groups of molecules thus held in place have a certain rotatory power of their own and this is superadded to that of the normal solution4 ,after a time1 under the stress of the action of the solvent1 these groups are broken up and the solution then assumes its normal condition4 #ajf4 ,gyrodynat of ,dextrose4--,the gyrodynat of dextrose1 as has already been mentioned1 increases with the degree of concentration1 thus showing a property directly opposite that of sucrose4 ,the general formula for the anhydrous sugar is a,d #eb4gah #j4jagjhgp #j4jjjdbgap4 ,in this formula p represents the grams of dextrose in #ajj grams of the solution4 ,in a ten per cent solution the gyrodynat of dextrose is therefore nearly exactly a,d#bj #ec4 ,as calculated by ,tollens the gyrodynats corresponding to several degrees of concentration are shown in the following table3 p grams in #ajj a,d#bj calculated for grams of solution4 anhydrous dextrose4 #g4fhai #eb4hi #i4biid #eb4id #i4cgab #eb4id #aj4jfad #eb4if #aj4fbgi #eb4ih #ab4iejh #ec4je #ah4fbaa #ec4be #ca4faci #ec4hc #dj4gdcb #ed4cd #dc4ihhc #ed4ed #ec4jbca #ee4ag #hb4faaa #eg4hj #ajg4 ,gyrodynats of ,other ,sugars4--,of the other sugars it will be sufficient to mention only levulose1 maltose1 lactose1 and raffinose4 ,for complete tables of gyrodynatic powers the standard books on carbohydrates may be consulted4#fi ,the gyrodynat of levulose is not definitely established4 ,at #ad the number is nearly expressed by a,d#ad -#ic4g4 ,invert sugar1 which should consist of exactly equal molecules of dextrose and levulose1 has a gyrodynat expressed by the formula a,d#j -#bg4i1 with a concentration equivalent to #ag4ba grams of sugar in #ajj cubic centimeters4 ,the gyrodynat decreases with increase of temperature1 according to the formula a,dt -7#bg4i - #j4cbt74 ,according to this formula the solution is neutral to polarized light at #hg4b1 and this corresponds closely to the data of experiment4 ,maltose1 in a ten per cent solution at #bj1 shows a gyrodynat of a,d#bj #ach4c4 ,the general formula for other degrees of concentration is a,d #adj4cge - #j4jahcgp - #j4jiet1 in which p represents the number of grams in #ajj grams of the solution and t the temperature of observation4 ,in the case of lactose a,d #eb4ec1 and this number does not appear to be greatly influenced by the degree of concentration2 but is somewhat diminished by a rising temperature4 ,the gyrodynat of raffinose in a ten per cent solution is a,d #ajd4e4 ,,chemical ,,methods ,,of ,,estimating ,,sugars4 #ajh4 ,general ,principles4--,the methods for the chemical estimation of sugars in common use depend on the reducing actions exerted on certain metallic salts1 whereby the metal itself or some oxid thereof1 is obtained4 ,the reaction is either volumetric or the resulting oxid or metal may be weighed4 ,the common method is1 therefore1 resolved into two distinct processes1 and each of these is carried out in several ways4 ,not all sugars have the faculty of exerting a reducing action on highly oxidized metallic salts and the most common of them all1 viz41 sucrose is practically without action4 ,this sugar1 however1 by simple hydrolysis1 becomes reducing1 but the two components into which it is resolved by hydrolytic action do not reduce metallic salts in the same proportion4 ,moreover1 in all cases the reducing power of a sugar solution is largely dependent on its degree of concentration1 and this factor must always be taken into consideration4 ,salts of copper and mercury are most usually selected to measure the reducing power of a sugar and in point of fact copper salts are almost universally used4 ,copper sulfate and carbonate are the salts usually employed1 and of these the sulfate far more frequently1 but after conversion into tartrate4 ,practically1 therefore1 the study of the reducing action of sugar as an analytical method will be confined almost exclusively to the determination of its action on copper tartrate4 ,direct gravimetric methods are also practiced to a limited extent in the determination of sugars as in the use of the formation of sucrates of the alkaline earths and of the combinations which certain sugars form with phenylhydrazin4 ,within a few years this last named reaction has assumed a marked degree of importance as an analytical method4 ,the most practical treatment of this section1 therefore1 for the limited space which can be given it1 will be the study of the reducing action of sugars1 both from a volumetric and gravimetric point of view1 followed by a description of the best approved methods of the direct precipitation of sugars by such reagents as barium hydroxid and phenylhydrazin4 ,,volumetric ,,methods4 #aji4 ,classification4--,among the volumetric methods will be given those which are in common use or such as have been approved by the practice of analysts4 ,since the use of mercuric salts is now practiced to a limited extent1 only a brief study of that process will be attempted4 ,with the copper methods a somewhat extended description will be given of those depending on the use of copper sulfate1 and a briefer account of the copper carbonate process4 ,in the copper sulfate method two distinct divisions must be noted1 viz41 first an indirect process depending first upon the reduction of the copper to a suboxid1 the subsequent action of this body on iron salts1 measured finally by titration with potassium permanganate2 and second1 a direct process determined either by the disappearance of the blue color from the copper solution1 or by the absence of copper from a drop of the solution withdrawn and tested with potassium ferrocyanid4 ,this last mentioned reaction is one which is found in common use4 ,the volumetric methods are not1 as a rule1 as accurate as the gravimetric1 depending on weighing the resultant metal1 but they are far more rapid and well suited to technical control determinations4 #aaj4 ,reduction of ,mercuric ,salts4--,the method of determining sugar by its action on mercuric salts1 is due to ,knapp4#gj ,the method is based on the observation that dextrose and other allied sugars1 will reduce an alkaline solution of mercuric cyanid1 and that the mercury will appear in a metallic state4 ,the mercuric liquor is prepared by adding to a solution of ten grams of mercuric cyanid1 #ajj cubic centimeters of a solution of caustic soda of #a4ade specific gravity1 and making the volume to one liter with water4 ,the solution of sugar to be titrated1 should be as nearly as possible of one per cent strength4 ,to #ajj cubic centimeters of the boiling solution1 the sugar solution is added in small portions from a burette and in such a way as to keep the whole mass in gentle ebullition4 ,to determine when all the mercuric salt has been decomposed1 a drop of the clear boiling liquid is removed and brought into contact with a drop of stannous chlorid solution on a white surface4 ,a brownish black coloration or precipitate will indicate that the mercury is not all precipitated4 ,fresh portions of the sugar must then be added1 until no further indication of the presence of mercury is noted4 ,the approximate quantity of sugar solution required to precipitate the mercury having thus been determined1 the process is repeated by adding rapidly1 nearly the quantity of sugar solution required1 and then only a few drops at a time1 until the reduction is complete4 ,one hundred cubic centimeters of the mercuric cyanid solution prepared as directed above1 will be completely reduced by #bjb milligrams of dextrose1 #bjj 0 0 invert sugar1 #aih 0 0 levulose1 #cjh 0 0 maltose1 #caa 0 0 lactose4 ,by reason of the unpleasant odor of the boiling mercuric cyanid when in presence of a reducing agent1 the process should be conducted in a well ventilated fume chamber4 ,with a little practice the process is capable of rapid execution1 and gives reasonably accurate results4 #aaa4 ,sachsse's ,solution4--,the solution of mercuric salts proposed by ,sachsse1 is made by dissolving eighteen grams of mercuric iodid in twenty-five cubic centimeters of an aqueous solution of potassium iodid4 ,to this solution are added #bjj cubic centimeters of potash lye1 containing eighty grams of caustic potash4 ,after mixing the solution1 the volume is completed to one liter4 ,the sugar solutions used to reduce this mixture1 should be more dilute than those employed with the mercuric cyanid1 and should not be over one-half per cent in strength4 ,the end of the reduction is determined as already described4 ,after a preliminary trial1 nearly all the sugar necessary to complete reduction1 should be added at once1 and the end of the reduction then determined by the addition of successive small quantities4 ,one hundred cubic centimeters of the mercuric iodid solution prepared as directed above1 require the following quantities of sugar to effect a complete reduction3 #cbe milligrams of dextrose1 #bfi 0 0 invert sugar1 #bac 0 0 levulose1 #dia 0 0 maltose1 #chg 0 0 lactose4 ,by reason of the great difference between the reducing power of dextrose and levulose in this solution1 it has been used in combination with the copper reduction method1 to be described1 to determine the relative proportion of dextrose and levulose in a mixture4#ga ,it is now known that copper solutions require slightly different quantities of dextrose1 levulose1 or invert sugar to effect complete reduction1 but the variations are not great and in the calculation above mentioned1 it may be assumed that these differences do not exist4 ,instead of using stannous chlorid as an indicator1 the end of the reaction may be determined as follows3 ,a disk of filtering paper is placed over a small beaker containing some ammonium sulfid4 ,a drop of the clear hot solution is placed on this disk1 and if salts of mercury be still present a dark stain will be produced2 or a drop of the ammonium sulfid may be brought near the moist spot formed by the drop of mercury salt4 ,an alkaline solution of zinc oxid may also be used4 ,the methods depending on the use of mercuric salts have1 of late1 been supplanted by better processes1 and space will not be given here to their further discussion4 #aab4 ,the ,volumetric ,copper ,methods4--,the general principle on which these methods depend1 is found in the fact that certain sugars1 notably1 dextrose1 7glucose71 levulose1 7fructose71 maltose and lactose1 have the property of reducing an alkaline solution of copper to a lower state of combination1 in which the copper is separated as cuprous oxid4 ,the end of the reaction is either determined by the disappearance of the blue color of the solution1 or by the reaction produced by a drop of the hot filtered solution1 when placed in contact with a drop of potassium ferrocyanid acidified with acetic4 ,the copper salt which is found to give the most delicate and reliable reaction1 is the tartrate4 ,the number of volumetric processes proposed and which are in use1 is very great1 and an attempt even to enumerate all of these can not be made in this volume4 ,a few of the most reliable and best attested methods will be given1 representing if possible1 the best practice in this and other countries4 ,the rate of reduction of the copper salt to suboxid1 is influenced by the rate of mixing with the sugar solutions1 the temperature1 the composition of the copper solution and the strength of the sugar solution4 ,the degree of reduction is also modified by the rate at which the sugar solution is added1 and by the degree and duration of heating1 and all these variables together1 make the volumetric methods somewhat difficult and their data1 to a certain extent1 discordant4 ,by reason1 however1 of the ease with which they are applied and the speed of their execution1 they are invaluable for approximately correct work and for use in technical control4 #aac4 ,historical4--,it is not the purpose in this paragraph to trace the development of the copper reduction method for the determination of reducing sugars1 but only to refer to the beginning of the exact analytical application of it4 ,peligot1 as early as #ahdd1 made a report to the ,society for the ,encouragement of ,national ,industry on methods proposed by ,barreswil and ,fromherz for the quantitive estimation of sugar by means of copper solution4#gb ,these methods were based on the property of certain sugars to reduce alkaline copper solution to a state of cuprous oxid first announced by ,trommer4#gc ,this was followed by a paper by ,falck on the quantitive determination of sugar in urine4#gd ,in #ahdh the methods1 which have been proposed1 were critically examined by ,fehling1 and from the date of his paper the determination of sugar by the copper method may be regarded as resting on a scientific basis4#ge ,since the date mentioned the principal improvements in the process have been in changing the composition of the copper solution in order to render it more stable1 which has been accomplished by varying the proportions of copper sulfate1 alkali and tartaric acid4 ,for the better keeping of the solution the method of preserving the copper sulfate and the alkaline tartrates in separate flasks and only mixing them at the time of use has been found very efficacious4#gf ,for testing for the end of the reaction by means of an acetic acid solution of potassium ferrocyanid the filtering tube suggested by the author1 the use of which will be described further on1 has proved quite useful4 ,pavy has suggested that by the addition of ammonia to the copper solution the precipitated suboxid may be kept in solution and the end of the reaction thus easily distinguished by the disappearance of the blue color4#gg ,allen has improved on this method by covering the hot mixture with a layer of paraffin oil whereby any oxidation of the suboxid is prevented4#gh ,the introduction and development of the gravimetric process depending on securing the reduced copper oxid in a metallic state as developed by ,allihn1 ,soxhlet1 and others1 completes the resum of this brief sketch of the rise and development of the process4 #aad4 ,action of ,alkaline ,copper ,solution on ,dextrose4--,the action to which dextrose and other reducing sugars are subjected in the presence of a hot alkaline copper solution is two-fold in its nature4 ,in the first place there is an oxidation of the sugar which is transformed into tartronic1 formic and oxalic acids1 the two latter in very small quantities4 ,at the same time another part of the sugar is attacked directly by the alkali and changed to complex products among which have been detected lactic1 oxyphenic and oxalic acids1 also two bodies isomeric with dioxyphenolpropionic acid4 ,when the sugar is in large excess melassic and glucic acids have also been detected4 ,the glucic acid may be regarded as being formed by simple dehydration but becomes at once resolved into pyrocatechin and gluconic acid according to the reaction ,c,h,o ,c,h,o ,c,h,o4 ,the gluconic acid also is decomposed and gives birth to lactic and glyceric acids according to the formula ,c,h,o ,c,h,o ,c,h,o4 ,the glyceric acid also in the presence of a base is changed into lactic and oxalic acids4 ,between lactic acid and pyrocatechin1 existing in a free state1 there is produced a double reciprocal etherification in virtue of which there arise two ethers isomeric with hydrocaffeic acid1 ,c,h,o4 ,one of these bodies is an acid and corresponds to the constitution ,,ch _/ ,o ,,ch _/ ,c,h ,,co,h 7#b7 ,,oh 7#b7 and the other is of an alcoholic nature corresponding to the formula ,,co ,,choh ,,ch 7#a7 _/ ,c,h ,,oh 7#b7 ,of all these products only oxyphenic and lactic acids and their ethers and oxalic acid remain unchanged and they can be isolated4 ,all the others are transformed in an acid state and they can only be detected by operating in the presence of metallic oxids capable of precipitating them at the time of their formation4#gi #aae4 ,fehling's ,solution4--,the copper solution which has been most used in the determination of reducing sugars is the one proposed by ,fehling as a working modification of the original reagent used by ,trommer4#hj ,following is the formula for the preparation of the fehling solution3 ,pure crystallized copper sulfate ,cu,s,o4#e;,h,o1 #cd4fd grams3 ,potassium tartrate1 #aej4jj 0 ,sodium hydroxid1 #ij4jj 0 ,the copper sulfate is dissolved in water and the potassium tartrate in the aqueous solution of the sodium hydroxid which should have a volume of about #gjj cubic centimeters4 ,the two solutions are mixed and the volume completed to a liter4 ,each cubic centimeter of this solution will be reduced by five milligrams of dextrose1 equivalent to four and a half milligrams of sucrose4 ,the reaction which takes place is represented by the following molecular proportions3 ,c,h,o #aj;,cu,s,o4#e;,h,o ,dextrose4 ,copper sulfate4 #ahj #bdid ,fehling's solution is delicate in its reactions but does not keep well1 depositing cuprous oxid on standing especially in a warm place exposed to light4 ,the fehling liquor was soon modified in its constitution by substituting #agc grams of the double sodium and potassium tartrate for the neutral potassium tartrate first used1 and1 in fact1 the original fehling reagent contained forty grams of copper sulfate instead of the quantity mentioned above4 ,other proportions of the ingredients are also given by many authors as fehling solution4 #aaf4 ,comparison of ,copper ,solutions for ,oxidizing ,sugars4--,for the convenience of analysts there is given below a tabular comparison of the different forms of fehling liquor which have been proposed for oxidizing sugars4 ,the table is based on a similar one prepared by ,tollens and ,rodewald1 amended and completed by ,horton4#ha ,the solutions are arranged alphabetically according to authors' names3 #a4 ,allihn3 #cd4f grams copper sulfate1 solution made up to half a liter2 #agc grams potassium-sodium tartrate2 #abe grams potassium hydroxid 7equivalent to #hi4b grams sodium hydroxid7 solution made up to half a liter4 #b4 ,a4 ,h4 ,allen3 #cd4fd grams copper sulfate1 solution made up to #ejj cubic centimeters2 #ahj grams potassium-sodium tartrate2 #gj grams sodium hydroxid 7not less than #ig ,na,o,h71 solution made up to half a liter4 #c4 ,bdeker3 #cd4fe grams copper sulfate2 #agc grams potassium-sodium tartrate2 #dhj cubic centimeters sodium hydroxid solution1 #a4ad specific gravity2 #fg4c grams sodium hydroxid2 fill to one liter2 #j4ahj gram grape sugar reduces according to ,bdeker1 #cf4a cubic centimeters of the copper solution #j4cig gram copper oxid4 ,the same quantity of milk sugar reduces1 however1 only twenty-seven cubic centimeters copper solution #j4bih copper oxid4 #d4 ,boussingault3 #dj grams copper sulfate2 #afj grams potassium tartrate2 #acj grams sodium hydroxid4 #e4 ,dietzsch3 #cd4fe grams copper sulfate2 #aej grams potassium-sodium tartrate2 #bej grams sodium hydroxid solution1 #a4bj specific gravity2 #aej grams glycerol4 #f4 ,fleischer3 #fi4bgh grams copper sulfate dissolved in about half a liter of water1 add to this #bjj grams tartaric acid2 fill to one liter with concentrated sodium hydroxid solution2 twenty cubic centimeters copper solution forty cubic centimeters sugar solution1 that contain in every cubic centimeter five milligrams grape sugar4 #g4 ,fehling3 #dj grams copper sulfate2 #afj grams di-potassium tartrate #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4ab specific gravity1 or from #ed4f to #fc4g grams sodium hydroxid1 fill to #aaed4d cubic centimeters4 #h4 ,gorup-,besanez3 #cd4fe grams copper sulfate2 #agc grams potassium-sodium tartrate2 #dhj cubic centimeters sodium hydroxid solution1 #a4ad specific gravity2 equal #fg4c sodium hydroxid4 ,fill to one liter4 #i4 ,grimaux3 #dj grams copper sulfate2 #afj grams potassium-sodium tartrate2 #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4bj specific gravity1 equal to #ib4e-ajg4i grams sodium hydroxid4 ,fill to #aaed4d cubic centimeters4 ,ten cubic centimeters of this solution are completely decolorized by #j4jej gram glucose4 #aj4 ,holdefleis3 #cd4fcb grams copper sulfate in one liter of water2 #abe grams potassium hydroxid1 equivalent to #hi4b grams sodium hydroxid2 #agc grams potassium-sodium tartrate4 ,fill to one liter4 #aa4 ,hoppe-,seyler3 #cd4fe grams copper sulfate2 #agc grams potassium-sodium tartrate2 #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4ab specific gravity2 equal to #fc4j-gc4e grams potassium hydroxid4 ,fill to one liter4 ,one cubic centimeter is reduced by exactly #j4jje gram grape sugar4 #ab4 ,krocker3 #f4bh grams copper sulfate2 #cd4f grams potassium-sodium tartrate2 #ajj cubic centimeters sodium hydroxid solution1 #a4ad specific gravity4 ,fill to #bjj cubic centimeters4 ,in #ajj cubic centimeters of this solution is contained #j4cad gram copper sulfate1 which is reduced by #j4jej grape sugar4 #ac4 ,liebermann3 #d grams copper sulfate2 #bj grams potassium-sodium tartrate2 #gj grams sodium hydroxid solution1 #a4ab specific gravity4 ,fill to #aae4e cubic centimeters4 #ad4 ,lwe3 #ae grams copper sulfate2 #fj grams glycerol2 #hj cubic centimeters sodium hydroxid1 #a4cd specific gravity2 #afj cubic centimeters water4 ,fill to half a liter4 #ae4 ,mohr3 #cd4fd copper sulfate2 #aej grams di-potassium tartrate2 #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4ab specific gravity1 equal to #gj4e-hb4c grams sodium hydroxid4 ,fill to one liter4 #af4 ,mrcker3 #ce grams copper sulfate1 solution made up to one liter3 #age grams potassium-sodium tartrate2 #abe grams potassium hydroxid1 equivalent to #hi4b grams sodium hydroxid1 solution made up to one liter4 #ag4 ,maumen3 #cge grams copper sulfate2 #ahh grams potassium-sodium tartrate2 #aff grams potassium hydroxid4 ,fill to nine liters4 #ah4 ,monier3 #dj grams copper sulfate2 #c grams stannic chlorid2 #hj grams cream of tartar2 #acj grams sodium hydroxid4 ,fill to one liter4 #ai4 ,neubauer and ,vogel3 #cd4fci grams copper sulfate2 #agc grams potassium-sodium tartrate2 #ejj-fjj grams sodium hydroxid solution1 #a4ab specific gravity4 ,fill to one liter4 #bj4 ,pasteur3 #dj grams copper sulfate2 #aje grams tartaric acid2 #hj grams potassium hydroxid2 #acj grams sodium hydroxid4 #ba4 ,possoz3 #dj grams copper sulfate2 #cjj grams potassium-sodium tartrate2 #bi grams sodium hydroxid2 #aei grams sodium bicarbonate1 allow to stand six months before use4 ,fill to one liter4 ,one cubic centimeter equals #j4jegg gram dextrose4 ,one cubic centimeter equals #j4jedh gram cane sugar4 #bb4 ,rth3 #cd4fd grams copper sulfate2 #adc grams potassium-sodium tartrate2 #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4ab specific gravity4 ,fill to one liter4 #bc4 ,rodewald and ,tollens3 #cd4fci grams copper sulfate1 solution made up to half a liter2 #agc grams potassium-sodium tartrate2 #fj grams sodium hydroxid1 solution made up to half a liter4 #bd4 ,schorlemmer3 #cd4fd grams copper sulfate2 #bjj grams potassium-sodium tartrate2 #fjj-gjj cubic centimeters sodium hydroxid solution1 #a4bj specific gravity4 ,fill to one liter4 #be4 ,soxhlet3 #cd4fci grams copper sulfate1 solution made up to half a liter4 #agc grams potassium-sodium tartrate2 #ea4f grams sodium hydroxid1 solution made up to half a liter4 #bf4 ,soldaini3 #c4dfd grams copper sulfate2 #big grams potassium bicarbonate4 ,fill to one liter4 #bg4 ,violette3 #cd4fd grams copper sulfate2 #ahg4j potassium-sodium tartrate2 #gh4j sodium hydroxid made up to one liter4 ,ten cubic centimeters equal #j4jej gram dextrose4 ,ten cubic centimeters equal #j4jdge gram cane sugar4 #aag4 ,volumetric ,method used in this ,laboratory4--,the alkaline copper solution preferred in this laboratory has the composition proposed by ,violette4 ,the copper sulfate and alkaline tartrate solutions are kept in separate vessels and mixed in proper proportions immediately before use1 and diluted with about three volumes of water4 ,the reduction is accomplished in a long test tube at least twenty-five centimeters in length1 and from thirty-five to forty millimeters in diameter4 ,the sugar solution employed should contain approximately one per cent of reducing sugar4 ,if it should have a greater content it should be reduced with water to approximately the one named4 ,if it have a less content1 it should be evaporated in a vacuum at a low temperature until it reaches the strength mentioned above4 ,a preliminary test will indicate almost the exact quantity of the sugar solution to be added to secure a complete reduction of the copper4 ,this having been determined the whole quantity should be added at once to the boiling copper solution1 the test tube held in the open flame of a lamp giving a large circular flame and the contents of the tube kept in brisk ebullition for just two minutes4 ,the lamp is withdrawn and the precipitated suboxid allowed to settle4 ,if a distinct blue color remain an additional quantity of the sugar solution is added and again boiled for two minutes4 ,when the blue coloration is no longer distinct1 the presence or absence of copper is determined by aspirating a drop or two of the hot solution with the apparatus described below4 ,this clear filtered liquor is then brought into contact with a drop of potassium ferrocyanid solution acidulated with acetic4 ,the production of a brown precipitate or color indicates that some copper is still present1 in which case an additional quantity of the sugar solution is added and the operation continued as described above until after the last addition of sugar solution no coloration is produced4 #aah4 ,the ,filtering ,tube4--,the filtering tube used in the above operation is made of a long piece of narrow glass tubing with thick walls4 ,the length of the tube should be from forty to forty-five centimeters4 ,one end of the tube being softened in the flame is pressed against a block of wood so as to form a flange4 ,over this flange is tied a piece of fine linen4#hb ,instead of using a linen diaphragm the tube is greatly improved1 as suggested by ,knorr1 by sealing into the end of the tube while hot a perforated platinum disk4 ,before using1 the tube is dipped into a vessel containing some suspended asbestos felt and by aspiration a thin felt of asbestos is formed over the outer surface of the platinum disk4 ,by inverting the tube the water which has entered during aspiration is removed4 ,the tube thus prepared is dipped into the boiling solution in the test tube above described and aspiration continued until a drop of the liquor has entered the tube4 ,it is then removed from the boiling solution1 the asbestos felt wiped off with a clean towel1 and the drop of liquor in the tube blown through the openings in the platinum disk and brought into contact with a drop of potassium ferrocyanid in the usual way4 ,in this way a drop of the liquor is secured without any danger of a reoxidation of the copper which may sometimes take place on cooling4 ,illustration3 ,,figure #db4 ,,apparatus ,,for ,,the ,,volumetric ,,estimation ,,of ,,reducing ,,sugars4 ,the careful analyst by working in this way with the volumetric method is able to secure highly accurate results4 ,the apparatus used is shown in the accompanying illustration4 #aai4 ,suppression of the ,error ,caused by the ,action of the ,alkali on ,reducing ,sugars4--,three methods are proposed by ,gaud for correcting or suppressing the error due to the action of the alkali upon reducing sugars4 ,in the first place1 the common method followed may be employed1 depending upon the use of an alkaline copper solution of known composition and the employment of a reducing sugar solution of a strength varying between one-half and one per cent4 ,the error which is introduced into such a reaction is a constant one and the solution having been tested once for all against pure sugar is capable of giving fairly accurate results4 ,in the second place1 a table may be constructed in which the error is determined for sugar solutions for varying strengths1 viz41 from one-tenth of one per cent to ten per cent4 ,if y represent the error and x the exact percentage of reducing sugar present then the correction may be made by the following formula2 y -#j4jjjjdhjax #j4jbhgfceix4 ,in order to use this formula in practice the percentage of reducing sugar obtained by the actual analysis must be introduced and may be represented by 4 ,the formula for correction then becomes #j4jbhgfx - #a4jjjjdhx #j2 whence the value of x is easily computed4 ,in the third place1 the error may be eliminated by substituting for an alkali which acts upon the glucose one which does not1 viz41 ammonia4 ,at the temperature of boiling water ammonia does not have any decomposing effect upon reducing sugars4 ,it is important1 however1 that the reduction take place in an inert atmosphere in order to avoid the oxidation of the dissolved cuprous oxid and the temperature need not be carried beyond #hj4 ,the end of the reaction can be easily distinguished in this case by the disappearance of the blue color4 ,when one reaction is finished the copper may be completely reoxidized by conducting through it a current of air or oxygen for half an hour1 when an additional quantity of ammonia may be added to supply any that may have evaporated1 and a new reduction accomplished with exactly the same quantity of copper as was used in the first4 ,the solution used by ,gaud contains #cf4fe grams of crystallized copper sulfate dissolved in water and the volume completed to one liter with ordinary aqueous ammonia4#hc #abj4 ,permanganate ,process for the ,estimation of ,reducing ,sugars4--,dextrose1 invert sugar1 and other reducing sugars can also be determined with a fair degree of accuracy by an indirect volumetric process1 in which a standard solution of potassium permanganate is used as the final reagent4#hd ,the principle of the process is based upon the observation that two molecules of dextrose reduce from an alkaline cupric tartrate solution five molecules of cuprous oxid4 ,the five molecules of cuprous oxid thus precipitated when added to an acid solution of ferric sulfate1 will change five molecules of the ferric sulfate to ten molecules of ferrous sulfate4 ,the reaction is illustrated by the following equation3 #e;,cu,o #e;,fe7,,so7 #e;,h,,so #aj;,cu,s,o #gae parts #bjjj parts #dij parts #aeie parts #aj;,fe,s,o #e;,h,o #aebj parts #ij parts ,the ten molecules of ferrous sulfate formed as indicated in the above reaction1 are reoxidized to ferric sulfate by a set solution of potassium permanganate4 ,this reaction is illustrated by the equation given below3 #aj;,fe,s,o ,k,mn,o #e;,h,,so #e;,fe7,,so7 #aebj parts #caf4b parts #ghd parts #bjjj parts #b,mn,s,o ,k,,so #h;,h,o #cjb parts #agd4b parts #add parts4 ,by the study of the above equations it is seen that two molecules of dextrose or other similar reducing sugar1 are equivalent to one molecule of potassium permanganate1 as is shown by the following equations3 #b;,c,h,o #e;,cu,o #aj;,fe,s,o ,k,mn,o #cfj parts #gae parts #aebj parts #caf4b parts ,it is thus seen that #caf4b parts by weight of potassium permanganate are equivalent to #cfj parts by weight of dextrose2 or one part of permanganate corresponds to #a4ache parts by weight of dextrose4 ,if1 therefore1 the amount of permanganate required in the above reaction to restore the iron to the ferric condition1 be multiplied by the factor mentioned above1 the quotient will represent in weight the amount of dextrose which enters into the reaction4 ,the standard solution of potassium permanganate should contain #d4cib grams of the salt in a liter4 ,one cubic centimeter of this solution is equivalent to five milligrams of dextrose4 #aba4 ,manipulation4--,the saccharine solution whose strength is to be determined should contain approximately about one per cent of sugar4 ,of this solution ten cubic centimeters are placed in a porcelain dish together with a considerable excess of fehling solution4 ,when no sucrose is present1 the mixture may be heated to the temperature of boiling water and kept at that temperature for a few minutes until all the reducing sugar is oxidized4 ,there should be enough of the copper solution used to maintain a strong blue coloration at the end of the reaction4 ,a greater uniformity of results will be secured by using in all cases a considerable excess of the copper solution4 ,when sucrose or other non-reducing sugars are present1 the temperature of the reaction should not be allowed to exceed #hj and the heating may be continued somewhat longer4 ,at this temperature the copper solution is absolutely without action on sucrose4 ,the precipitated suboxid is allowed to settle1 the supernatant liquid poured off through a filter and the suboxid washed thoroughly a number of times by decantation with hot water1 the washings being poured through the filter4 ,this process of washing is greatly facilitated by decanting the supernatant liquid from the porcelain dish first into a beaker and from this into a third beaker and so on until no suboxid is carried off4 ,finally the wash water is poured through a filter-paper bringing as little as possible of the suboxid onto the paper4 ,the suboxid on the filter-paper and in the beakers is next dissolved in a solution of ferric sulfate made strongly acid with sulfuric2 or in a sulfuric acid solution of ammonia ferric sulfate which is more easily obtained free from impurities than the ferric sulfate4 ,when all is dissolved from the beakers the solution is poured upon the suboxid which still remains in the porcelain dish4 ,when the solution is complete it is washed into a half liter flask and all the vessels which contain the suboxid are also thoroughly washed and the wash waters added to the same flask4 ,the whole is rendered strongly acid with sulfuric and made up to a volume of half a liter4 ,the process carried out as directed1 when tested against pure sugar1 gives good results1 not varying from the actual content of the sugar by more than one-tenth per cent below or three-tenths above the true content4 ,the distinct pink coloration imparted to the solution by the permanganate solution as soon as the iron is all oxidized to the ferric state marks sharply the end of the reaction4 ,in this respect this process is very much to be preferred to the usual volumetric processes depending upon the coloration produced with potassium ferrocyanid by a copper salt for distinguishing the end of the reaction4 ,it is less convenient than the ordinary volumetric process by reason of the somewhat tedious method of washing the precipitated cuprous oxid4 ,when a large number of analyses is to be made1 however1 the whole can be washed with no more expenditure of time than is required for a single sample4 ,one analyst can1 in this way1 easily attend to fifty or a hundred determinations at a time4 ,in the application of the permanganate method to the analysis of the juices of sugar cane and sorghum it is directed to take #ajj cubic centimeters of the expressed juice and clarify by the addition of twenty-five cubic centimeters of basic lead acetate1 diluted with water1 containing enough of the lead acetate1 however1 to produce a complete clarification4 ,it is not necessary to remove the excess of lead from the filtrate before the determination4 ,ten cubic centimeters of the filtrate correspond to eight cubic centimeters of the original juice4 ,for percentage calculation the specific gravity of the original juice must be known4 ,before the addition of the alkaline copper solution1 from fifty to seventy-five cubic centimeters of water should be added to the clarified sugar juice and the amount of fehling solution used in each case should be from fifty to seventy-five cubic centimeters4 ,the heating at #ge should be continued for half an hour in order to insure complete reduction and oxidation of the sugar4 ,the sucrose can also be estimated in the same juices by inverting five cubic centimeters of the clarified juice with five cubic centimeters of dilute hydrochloric acid1 by heating for an hour at a temperature not above #ij4 ,before adding the acid for inversion1 about #ajj cubic centimeters of water should be poured over the five cubic centimeters of sugar solution4 ,the washing of the suboxid and the estimation of the amount reduced are accomplished in the manner above described4 ,this method has been extensively used in this laboratory and with very satisfactory results4 ,the only practical objection which can be urged to it is in the time required for filtering4 ,this fault is easily remedied by adopting the method of filtering through asbestos felt described in the next paragraph4 ,for the sake of uniformity1 however1 the copper solution should be boiled for a few minutes before the addition of the sugar in order to expel all oxygen1 the sugar solutions should be made with recently boiled water and the precipitation of the suboxid should be accomplished by heating for just thirty minutes at #ge4 ,at the end of this time an equal volume of cold1 recently boiled1 water should be added and the filtration at once accomplished4 #abb4 ,modified ,permanganate ,method4--,the permanganate method as used by ,ewell1 in this laboratory1 is conducted as follows3 ,after the precipitate is obtained1 according to the directions given in the methods described1 it is thoroughly washed with hot1 recently boiled water1 on a gooch4 ,the asbestos1 with as much of the precipitate as possible1 is transferred to the beaker in which the precipitation was made1 beaten up with from twenty-five to thirty cubic centimeters of hot1 recently boiled water1 and from fifty to seventy-five cubic centimeters of a saturated solution of ferric sulfate in twenty-five per cent sulfuric acid are added to the beaker and then poured through the crucible to dissolve the cuprous oxid remaining therein4 ,if the precipitate be first beaten up with water as directed1 so that no large lumps of it remain1 there is no difficulty in dissolving the oxid in the ferric salt2 while if any lumps of the oxid be allowed to remain there is great difficulty4 ,after the solution is obtained1 it is titrated with a solution of potassium permanganate of such a strength that each cubic centimeter is equivalent to #j4ja gram of copper4 ,in triplicate determinations made by this method the precipitates obtained required after solution in the ferric salt1 #bh4g1 #bh4i1 #bh4f cubic centimeters of potassium permanganate solution1 respectively4 ,for the quantities taken this was equivalent to an average percentage of reducing sugars of #d4ai4 ,the percentage obtained by the gravimetric method was #d4bf4 ,the method seems to be sufficiently accurate for all ordinary purposes and is extremely rapid4 ,the permanganate solution used should be standardized by means of metallic iron1 but in ordinary work it is also recommended to standardize by check determinations of reducing sugars in the same sample by the gravimetric method4 #abc4 ,determination of ,reducing ,sugar by the ,specific ,gravity of the ,cuprous ,oxid4--,gaud proposes to determine the percentage of reducing sugar from the specific gravity of the cuprous oxid4 ,the manipulation is carried out as follows3 ,in a porcelain dish are placed fifty cubic centimeters of the alkaline copper solution and an equal quantity of water and the mixture maintained in ebullition for two or three minutes4 ,the dish is then placed on a boiling water-bath and twenty-five cubic centimeters of a reducing sugar of approximately one per cent strength added at once4 ,the reduction is thus secured at a temperature below #ajj1 which is an important consideration in securing the minimum decomposing effect of the alkali upon the sugar4 ,the dish is kept upon the water-bath for about ten minutes when the reduction is complete and the supernatant liquor should still be intensely blue4 ,the precipitate is washed by decantation with boiling water1 taking care to avoid the loss of any of the cuprous oxid4 ,the washing is continued until the wash waters are neutral to phenolphthalein4 ,the cuprous oxid is then washed into a pyknometer of from twenty to twenty-five cubic centimeters capacity1 the exact content of which has been previously determined at zero4 ,it is filled with boiling water1 the stopper inserted1 and after cooling the flask is weighed4 ,let ,p be the weight of the pyknometer plus the liquid and the precipitate1 the total volume of which is equal to the capacity of the flask at the temperature at which it was filled1 that is ,v ,v #a #c7t-t74 ,this formula is essentially that given in paragraph #ea1 for calculating the volume of a pyknometer at any temperature1 substituting for #c1 the cubical expansion of glass1 viz41 #j4jjjjbe4 ,the specific gravity of the dry cuprous oxid is #e4hha and let the specific gravity of water at the temperature of filling1 which can be taken from any of the tables of the density of water1 be d4 ,the total weight p of the precipitated suboxid may then be calculated by the following formula3 ,p-,vd ,p -----------4 #a - d ---- ,the density of water at #ii1 which is about the mean temperature of boiling water for laboratories in general1 is #j4ieicd1 and this may be taken as the weight of one cubic centimeter for purposes of calculation in the formula above4 ,in order to obtain exact results1 it is important that the weight ,p be reduced to a vacuum4 ,the weight of cuprous oxid not varying proportionally to the weight of reducing sugar1 it is necessary to prepare a table showing the principal numerical values of the two1 in order to be able to calculate easily all the possible values1 either directly from the table or by appropriate interpolations4 ,following are the chief values which are necessary for the calculation3 ,milligrams ,milligrams ,milligrams ,milligrams cuprous oxid4 dextrose4 cuprous oxid4 dextrose4 #aj #e4dac #ajj #df4bba #bj #i4gfa #bjj #ia4jdg #cj #ad4aig #cjj #ach4hdb #ej #bc4jcf #djj #ahh4ibh ,it is claimed by the author that the above method is both simple and rapid and can be applied with an error of not more than one-thousandth if the corrections for temperature and pressure be rigorously applied4#he #abd4 ,the ,copper ,carbonate ,process4--,while the copper solutions which have been mentioned in previous paragraphs have only a slight action on sucrose and dextrin yet on prolonged boiling even these bodies show a reducing effect due probably to a preliminary change in the sugar molecules whereby products analogous to dextrose or invert sugar are formed4 ,in order to secure a reagent1 to which the sugar not reducing alkaline copper solutions might be more resistant ,soldaini has proposed to employ a liquor containing the copper as carbonate instead of as tartrate4#hf ,this solution is prepared by adding to a solution of forty grams of copper sulfate one of equal strength of sodium carbonate4 ,the resulting copper carbonate and hydroxid are collected on a filter1 washed with cold water1 and dried4 ,the reaction which takes place is represented by the following formula3 #b;,cu,s,o #b,na,,co ,h,o ,cu,c,o ,cu,o,h #b,na,,so ,,co4 ,the dry precipitate obtained1 which will weigh about fifteen grams1 is placed in a large flask with about #dbj grams of potassium bicarbonate and #adjj cubic centimeters of water4 ,the contents of the flask are heated on a steam-bath for several hours with occasional stirring until the evolution of carbon dioxid has ceased4 ,during this time the liquid is kept at the same volume by the addition of water1 or by attaching a reflux condenser to the flask4 ,the potassium and copper compounds at the end of this time will be found dissolved and the resulting liquor will have a deep blue color4 ,after filtration the solution is boiled for a few minutes and cooled to room temperature4 ,the volume is then completed to two liters4 ,a more direct method of preparing the solution1 and one quite as effective1 consists in adding the solution of the copper sulfate directly to the hot solution of potassium bicarbonate and heating and shaking the mixture until the copper carbonate formed is dissolved4 ,after filtering the volume is made as above4 ,the proportions of reagents employed are placed by ,preuss at #ae4h grams of crystallized copper sulfate and #eid grams of potassium bicarbonate4#hg ,the soldaini reagent is extremely sensitive and is capable of detecting as little as half a milligram of invert sugar4 ,the presence of sucrose makes the reagent more delicate1 and it is especially useful in determining the invert sugar arising during the progress of manufacture by the action of heat and melassigenic bodies on sucrose4 #abe4 ,the ,analytical ,process4--,as in the case of fehling solution a great many methods of conducting the analysis with the soldaini reagent have been proposed4 ,the general principle of all these processes is the one already described for the alkaline copper tartrate solution1 viz41 the addition of the reducing sugar solution to the boiling reagent1 and the determination of the end of the reaction by the disappearance of the copper4#hh ,practically1 however1 these methods have had no general application1 and the use of the soldaini reagent has been confined chiefly to the determination of invert sugar in presence of a large excess of sucrose4 ,for this purpose the sugar solution is not added until the blue color of the reagent has been destroyed1 but on the other hand1 the reagent has been used in excess1 and the cuprous oxid formed collected and weighed as metallic copper4 ,the weight of the metallic copper found1 multiplied by the factor #j4cedf1 gives the weight of invert sugar in the volume of the sugar solution used4 ,according to ,preuss1 the factor is not a constant one1 but varies with the quantity of invert sugar present1 as is seen in the formula y #b4bhfh #c4cx #j4jjdax1 in which x the invert sugar1 and y the metallic copper4#hi #abf4 ,tenth ,normal ,copper ,carbonate ,solution4--,in the study of some of the solutions of copper carbonate1 proposed for practical work1 ,ettore ,soldaini was impressed with the difficulty of dissolving so large a quantity of carbonate in the solvent employed4#ij ,the solution recommended by ,bodenbender and ,scheller1#ia in which forty grams of the crystallized copper sulfate were used1 failed to disclose an equivalent amount of copper in the reagent ready for use4 ,for this reason a tenth-normal copper solution is prepared by ,soldaini containing the equivalent of #c4dfd grams of copper sulfate in one liter4 ,the reagent is easily prepared by adding slowly the dissolved or finely powdered copper salt to a solution of #big grams of potassium bicarbonate1 and after complete solution of the copper carbonate formed1 completing the volume to one liter4 ,with this reagent as little as one-quarter of a milligram of reducing sugar can be easily detected4 ,for the quantitive estimation of sugar a solution of the above strength is to be preferred to the other forms of the soldaini reagent by reason of the ease of direct comparison with standard fehling solutions4 ,the analytical process is conducted with the tenth-normal solution1 prepared by ,soldaini and described above1 as follows3 ,place #ajj cubic centimeters of the reagent in each of several porcelain dishes heat to boiling1 and add little by little the sugar solution to one dish until the blue color has disappeared4 ,having thus determined nearly the exact quantity of sugar solution required for the copper in #ajj cubic centimeters of the reagent the whole of the sugar solution is added at once1 varying slightly the amounts added to each dish4 ,the boiling is continued for fifteen minutes1 and the contents of the dishes poured on filters4 ,that filtrate which contains neither copper nor sugar represents the exact quantity of sugar solution which contained fifty milligrams of dextrose4 #abg4 ,relation of ,reducing ,sugar to ,quantity of ,copper ,suboxid ,obtained4--,the relation of the quantity of copper reduced to the amount of sugar oxidized by the copper carbonate solution has been determined by ,ost1 and the utility of the process thereby increased4#ib ,the solution used should have the following composition3 #bc4e grams of crystallized copper sulfate1 #bej grams of potassium carbonate1 and #ajj grams of potassium bicarbonate in one liter4 ,without an indicator the end reaction is distinctly marked by the passage of the blue color into a colorless solution4 ,ost affirms that this solution is preferable to any form of fehling liquor because it can be kept indefinitely unchanged2 it attacks sucrose far less strongly1 and an equal quantity of sugar precipitates nearly double the quantity of copper4 ,the boiling requires a longer time1 as a rule ten minutes1 but this is a matter of no importance1 when the other advantages are taken into consideration4 ,the relations of the different sugars to the quantity of copper precipitated are given in the table in the next paragraph4 #abh4 ,factor for ,different ,sugars4--,for pure dextrose the relation between sugar and copper reduced has been determined by ,ost1 and the data are given in the table below4 ,the data were obtained by adding to fifty cubic centimeters of the copper solution twenty-five cubic centimeters of sugar solutions of varying strength and collecting1 washing1 and reducing the cuprous oxid obtained in a current of hydrogen in a glass tube by the method described further on4 ,the boiling in all cases was continued1 just ten minutes1 although a slight variation from the standard time did not produce so great a difference as with fehling reagent4 ,in the case of dextrose1 when fifty milligrams were used with fifty cubic centimeters of the solution1 the milligrams of copper obtained after six1 ten and twenty minutes' boiling were #afd4f1 #afe4e1 and #aff4i respectively4#ic ,the data differ considerably from those obtained by ,herzfeld1 but in his experiments the boiling was continued only for five minutes1 and this is not long enough to secure the proper reduction of the copper4#id ,,table ,,showing ,,the ,,quantity ,,of ,,copper ,,reduced ,,by ,,different ,,sugars4 ,copper4 ,invert ,sugar4 ,dextrose4 ,levulose4 ,galactose4 ,arabinose4 ,milli- ,milli- ,milli- ,milli- ,milli- ,milli- grams4 grams4 grams4 grams4 grams4 grams4 #ej #ae4b #ae4f #ad4g #ag4d #ag4j #ee #af4f #ag4j #af4a #ai4a #ah4f #fj #ah4j #ah4e #ag4e #bj4h #bj4c #fe #ai4d #ai4i #ah4i #bb4e #ba4i #gj #bj4h #ba4d #bj4c #bd4b #bc4e #ge #bb4c #bb4i #ba4g #be4i #be4a #hj #bc4g #bd4d #bc4j #bg4g #bf4g #he #be4b #be4h #bd4c #bi4c #bh4c #ij #bf4f #bg4c #be4g #ca4a #bi4i #ie #bh4a #bh4h #bg4a #cb4h #ca4e #ajj #bi4e #cj4c #bh4e #cd4e #cc4a #aje #ca4j #ca4h #bi4i #cf4b #cd4g #aaj #cb4d #cc4c #ca4b #ch4j #cf4c #aae #cc4i #cd4h #cb4f #ci4g #cg4i #abj #ce4c #cf4c #cd4j #da4d #ci4e #abe #cf4h #cg4h #ce4d #dc4a #da4a #acj #ch4b #ci4c #cf4h #dd4h #db4h #ace #ci4g #dj4h #ch4b #df4e #dd4d #adj #da4a #db4c #ci4f #dh4c #df4j #ade #db4f #dc4h #da4j #ej4j #dg4f #aej #dd4j #de4c #db4e #ea4h #di4c #aee #de4e #df4h #dc4i #ec4f #ej4i #afj #dg4j #dh4c #de4c #ee4d #eb4f #afe #dh4e #di4h #df4g #eg4b #ed4c #agj #ej4j #ea4d #dh4a #ei4j #ee4i #age #ea4e #eb4i #di4e #fj4h #eg4e #ahj #ec4j #ed4e #ea4j #fb4g #ei4b #ahe #ed4e #ef4j #eb4e #fd4e #fj4i #aij #ef4j #eg4f #ed4j #ff4d #fb4g #aie #eg4e #ei4b #ee4e #fh4c #fd4d #bjj #ei4a #fj4h #eg4j #gj4c #ff4b #bje #fj4g #fb4d #eh4f #gb4c #fh4j #baj #fb4d #fd4a #fj4b #gd4c #fi4h #bae #fd4a #fe4h #fa4h #gf4c #ga4f #bbj #fe4h #fg4e #fc4e #gh4c #gc4e #bbe #fg4e #fi4b #fe4b #hj4c #ge4d #bcj #fi4c #gj4i #ff4i #hb4d #gg4c #bce #ga4a #gb4g #fh4g #hd4e #gi4c #bdj #gb4i #gd4e #gj4f #hf4f #ha4c #bde #gd4h #gf4d #gb4e #hh4i #hc4d #bej #gf4g #gh4d #gd4d #ia4b #he4e #bee #gh4f #hj4e #gf4e #ic4e #hg4f #bfj #hj4e #hb4h #gh4h #ie4i #hi4h #bfe #hb4e #he4a #ha4a #ih4c #ib4b #bgj #hd4g #hg4e #hc4e #ajj4g #id4f #bge #hg4a #hi4i #he4i #ajc4c #ig4a #bhj #hi4g #ib4d #hh4f #ajf4a #ii4f #bhe #ib4c #id4i #ia4c #aji4j #ajb4c #bij #ie4a #ig4f #id4b #aab4j #aje4a #bie #ih4j #ajj4d #ig4b #aae4a #ajg4i #bih #ajj4j #ajb4e #ii4j #aag4j #aji4e ,,volumetric ,,methods ,,based ,,upon ,,the ,,use ,,of ,,an ,,ammoniacal ,,copper ,,solution4 #abi4 ,pavy's ,process4--,the well-known solubility of cuprous oxid in ammonia led ,pavy to adopt a copper reagent containing ammonia in the volumetric determination of reducing sugars4#ie ,in ,pavy's process an alkaline copper solution is employed made up in the usual way1 to which a sufficient quantity of ammonia is added to hold in solution all the copper when precipitated as cuprous oxid4 ,the solution used by ,pavy has the following composition3 ,one liter contains ,crystallized copper sulfate #cd4fe grams ,potassium-sodium tartrate #agc4jj 0 ,caustic potash #afj4jj 0 ,for use #abj cubic centimeters of the above reagent are mixed with #cjj of ammonia of specific gravity #j4hh1 and the volume completed to one liter with distilled water4 ,twenty cubic centimeters of this reagent are equivalent to ten milligrams of dextrose or invert sugar when added in a one per cent solution4 ,in the use of ammoniacal copper solution1 care must be taken that all the liquids employed be entirely free of oxygen and that the contents of the flask in which the reduction takes place be in some way excluded from contact with the air4 ,pavy secured this by conducting the reduction in a flask closed with a stopper carrying two holes2 one of these served for the introduction of the burette carrying the sugar solution and the other carried a tube dipping into a water seal by means of a slit rubber tube1 which would permit of the exit of the vapors of steam and ammonia1 but prevent the regurgitation of the water into the flask4 ,the complete decoloration of the copper solution marks the end of the reaction4 ,the usual precautions in regard to the length of the time of boiling must be observed4 ,it is easy to see that in the ,pavy process the quantity of ammonia in the solution is rapidly diminished during the boiling and this has led to the suggestion of other methods to exclude the air4 ,among these have been recommended the introduction of a current of hydrogen or carbon dioxid4 ,one of the best methods of procedure is that proposed by ,allen1 who recommends covering the copper solution by a layer of paraffin oil 7kerosene74#if #acj4 ,process ,of ,peska4--,peska has also independently made use of ,allen's method of covering the solutions with a layer of paraffin oil and finds it reliable4#ig ,the copper reagent employed by him has the following composition3 ,crystallized copper sulfate #f4ibg grams ,ammonia1 twenty-five per cent strength #afj4jj cc4 ,the copper sulfate is dissolved in water1 the ammonia added1 and the volume completed to half a liter with distilled water4 ,a second solution containing half a liter is made by dissolving #cd4e grams of potassium-sodium tartrate and ten grams of sodium hydroxid and completing the cool solution to half a liter with distilled water4 ,in all cases the water used in making up the above solutions must be freshly boiled to exclude the air4 ,for the titration1 fifty cubic centimeters of each of the above solutions are taken1 mixed and covered with a layer of paraffin oil half a centimeter in depth4 ,the reduction is not accomplished at a boiling temperature1 but at from #hj to #he4 ,the manipulation is conducted as follows3 ,the mixed solutions are placed in a beaker1 covered with oil1 and heated to #hj4 ,the temperature is measured by a thermometer which also serves as a stirring rod4 ,the sugar solution is run down the sides of the beaker from a burette of such a shape as to be protected from the heat4 ,after each addition of the sugar solution the mixture is carefully stirred1 keeping the temperature at from #hj to #he4 ,the first titration is made to determine approximately the quantity of sugar solution necessary to decolorize the copper4 ,this done1 the actual titration is accomplished by adding at once the total amount of sugar solution necessary to decolorize1 less about one cubic centimeter4 ,any sugar solution adhering to the side of the beaker is washed down by distilled water1 the contents of the beaker well stirred1 and the temperature kept at #he for two minutes4 ,the rest of the sugar solution is then added in quantities of one-tenth of a cubic centimeter until the decoloration is completed4 ,the total time of the final titration should not exceed five minutes4 ,the sugar solution should be as nearly as possible of one per cent strength4 ,if a lower degree of strength be employed a larger quantity of the sugar is necessary to reduce a given quantity of copper4 ,in the case of dextrose1 when a one per cent solution is used1 eight and two-tenths cubic centimeters1 corresponding to #hj4b milligrams of dextrose1 are required to reduce #ajj cubic centimeters of the mixed reagent4 ,on the other hand1 when the sugar solution is diluted to one-tenth of a per cent strength #hb4a milligrams are required4 ,with invert sugar slightly larger quantities are necessary1 the reducing power being as #id4i to #ajj as compared with dextrose4 ,with a one per cent strength of invert sugar it is found that eighty-four milligrams are required to reduce #ajj cubic centimeters of the mixed reagent and when the strength of the invert sugar is reduced to one-tenth per cent #hg4jc milligrams are required4 #aca4 ,method ,of ,allein and ,gaud4--,allein and ,gaud have proposed a further modification of the ammonia process which consists essentially in the suppression of rochelle salt and fixed caustic alkali and the entire substitution therefor of ammonia4 ,ammonia acts with much less vigor upon sugars than the caustic alkalies1 and it is therefore claimed that the decomposition of the sugar due to the alkali is reduced to a minimum when ammonia is employed4#ih ,the copper solution is made as follows3 ,dissolve #h4giaf grams of electrolytic copper in ninety-three grams of concentrated sulfuric acid diluted with an equal volume of water4 ,complete the resulting solution to one liter with concentrated ammonia4 ,ten cubic centimeters of this solution are equal to fifty grams of dextrose4 ,it is recommended that the reduction be accomplished in an atmosphere of hydrogen1 but it is apparent that the use of kerosene is permissible in this case1 and on account of its greater simplicity it is to be recommended as the best means of excluding the oxygen4 ,the reduction is accomplished at a temperature of about #hj4 ,it is also proposed to reoxidize the copper by substituting a current of air for the hydrogen at the end of the reaction1 and thus use the same copper a number of times4 ,the danger of loss of ammonia1 and the difficulty of determining when the oxidation is complete1 render this regeneration of the reagent undesirable4 #acb4 ,method of ,gerrard4--,the method of ,gerrard does not depend upon the use of ammonia1 but the principle involved is the same1 viz41 the holding of the separated cuprous oxid in solution and the determination of the end of the reaction by the disappearance of the blue color4 ,as first proposed by ,gerrard1 the copper sulfate solution is made of double the strength usually employed and to each #ajj cubic centimeters thereof1 before use1 three and three-tenths grams of potassium cyanid are added4 ,this is sufficient to hold the precipitated cuprous oxid in solution4#ii ,the original method of ,gerrard is found difficult of execution and the author1 in conjunction with ,allen1 has lately modified it and reduced it to a practical working basis4#ajj ,in the new method the ordinary fehling solution is employed and it is prepared for use in the following way3 ,ten cubic centimeters of the fehling solution1 or half that quantity of each of the component parts kept in separate bottles1 are placed in a porcelain dish with forty cubic centimeters of water and brought to the boiling-point4 ,to the boiling liquid is added1 from a pipette1 a five per cent solution of potassium cyanid until the blue color just disappears1 or only a very faint tint of blue remains1 avoiding any excess of the cyanid4 ,a second portion of the fehling solution equal to that first employed is added1 and to the boiling mixture the solution of sugar is added1 from a burette1 until the blue color disappears4 ,the contents of the dish should be kept boiling during the addition of the sugar solution4 ,the volume used will contain fifty milligrams of dextrose4 ,the sugar solution should be of such a strength as to contain no more than half a per cent of reducing sugar4 ,the principle of the preparation of the solution may be stated as follows3 ,if to a solution of copper sulfate1 potassium be added until the blue color disappears1 a double cyanid of copper and potassium cyanid is formed according to the following reaction3 ,cu,s,o #d,,kcn ,cu7,,cn74#b,,kcn ,k,,so4 ,this double cyanid is a salt of considerable stability4 ,it is not decomposed by alkalies1 hydrogen or ammonium1 sulfid4 ,with mineral acids it gives a whitish1 curdy precipitate4 ,with fehling solution the same double cyanid is formed as that described above4 ,if1 however1 fehling solution be present in excess of the amount necessary to form the double cyanid of copper1 this excess can be used in the oxidation of reducing sugar and the colorless condition of the solution will be restored as soon as the excess of the fehling is destroyed4 ,the double cyanid holds in solution the cuprous oxid formed and thus complete decoloration is secured4 #acc4 ,sidersky's ,modification of ,soldaini's ,process4--,in all cases where the sugar solutions are not too highly colored1 ,sidersky finds that the method of reduction in a large test tube1 as practiced by ,violette1 is applicable with the copper carbonate solution4#aja ,for more exact work it is preferred to determine the quantity of copper reduced by an indirect volumetric method4 ,the sugar solution1 properly clarified and the lead removed if subacetates have been used1 is made of such a volume as to contain less than one per cent of reducing sugars4 ,in a flask or large test tube are placed #ajj cubic centimeters of the copper solution1 which is boiled for a short time and the sugar solution added1 little by little1 from a pipette1 at such a rate as not to stop the ebullition4 ,the boiling is continued for five minutes after the last addition of the sugar4 ,the vessel is taken from the flame and #ajj cubic centimeters of cold water added1 the whole brought on an asbestos felt and the cuprous oxid washed with hot water until the alkaline reaction has disappeared4 ,the residual cuprous oxid is dissolved in a measured quantity of set sulfuric acid1 semi- or fifth-normal1 a few particles of potassium chlorate added1 and the mixture boiled to convert any cuprous into cupric sulfate4 ,the reaction is represented by the following formula3 #c;,cu,o #f;,h,,so ,k,cl,o #f;,cu,s,o ,k,cl #f;,h,o4 ,the residual sulfuric acid is titrated with a set alkali in excess1 ammonia being preferred4 ,the solution of ammonia is made by diluting #bjj cubic centimeters of commercial aqua ammonia with #hjj of water4 ,its strength is determined by adding a little copper sulfate solution as indicator and then the set solution of sulfuric acid until the blue color disappears4 ,the copper sulfate secured from the cuprous sulfate as described above is cooled1 and a quantity of the ammonia1 equal to twenty-five cubic centimeters of the set sulfuric acid1 added4 ,the excess of the ammonia is then determined by titration with the sulfuric acid1 the disappearance of the blue color being the indication of the end of the reaction4 ,the number of cubic centimeters of the set sulfuric acid required to saturate the ammonia represents the equivalent of cuprous oxid originally present4 ,one cubic centimeter of normal sulfuric acid is equivalent to #j4jcag gram of metallic copper4 ,to determine the weight of invert sugar oxidized1 multiply the weight of copper1 calculated as above described1 by the factor #j4cedf4ajb ,for a general application of this method of analysis the relative quantities of copper reduced by different quantities of sugar must be taken into consideration4 ,while1 as has already been stated1 the copper carbonate process has heretofore been applied chiefly to the detection of invert sugar1 it has merits which justify the expectation that it may some time supplant the fehling liquor both for volumetric and gravimetric work4 ,large volumes of the reagent can be prepared at once and without danger of subsequent change4 ,the action of the reagent on the hexobioses and trioses is far less vigorous than that of the alkaline copper tartrate1 and the end reactions for volumetric work are1 at least1 as easily determined in the one case as the other4 #acd4 ,method ,depending on ,titration of ,excess of ,copper4--,instead of measuring the quantity of copper reduced1 either by its disappearance or by reducing the cuprous oxid to a metallic state1 ,politis has proposed a method of analysis depending on the titration of the residual copper4#ajc ,the reagents employed are3 7#a7 ,a copper solution containing #bd4ie grams of crystallized copper sulfate1 #adj grams of sodium and potassium tartrate1 and twenty-five grams of sodium hydroxid in one liter3 7#b7 ,a solution of sodium thiosulfate containing #bd4h grams of the salt in one liter3 7#c7 ,a solution of potassium iodid containing #ab4g grams of iodin in one liter4 ,the reaction is represented by the formula #b;,cu,cl #d,,ki ,cu,i #d,k,cl ,i4 ,the analytical process is carried out as follows3 ,in a #ajj cubic centimeter flask are boiled fifty cubic centimeters of the copper solution1 ten cubic centimeters of about one-tenth per cent reducing sugar solution are added1 the boiling continued for five minutes1 the flask filled to the mark with boiling water and its contents filtered4 ,fifty cubic centimeters of the hot filtrate are cooled1 slightly acidified1 potassium iodid solution added in slight excess2 and the iodin set free determined by titration with sodium thiosulfate4 ,the quantity of iodin obtained corresponds to the unreduced copper remaining after treatment with the reducing sugar4 ,the number of cubic centimeters of thiosulfate used subtracted from twenty-five will give the number of cubic centimeters of the copper solution which would be reduced by five cubic centimeters of the sugar solution used4 ,example4--,in the proportions given above it was found that eleven cubic centimeters of thiosulfate were required to saturate the iodin set free4 ,then #be - #aa #ad cubic centimeters of copper solution reduced by five cubic centimeters of the sugar solution4 ,since one cubic centimeter of the copper solution is reduced by #j4jjcf gram of dextrose the total dextrose in the five cubic centimeters #j4jjcf #e #j4jahj gram4 ,the above method does not seem to have any practical advantage over those based on noting the disappearance of the copper and is given only to illustrate the principle of the process4 ,while the titration of the iodin by sodium thiosulfate is easily accomplished in the absence of organic matter1 it becomes difficult1 as shown by ,ewell1 when organic matters are present1 as they always are in the oxidation of a sugar solution4 ,ewell has therefore proposed to determine the residual copper by a standard solution of potassium cyanid1 but the method has not yet been developed4#ajd ,,gravimetric ,,copper ,,methods4 #ace4 ,general ,principles4--,in the preceding pages the principles of the volumetric methods of sugar analysis by means of alkaline copper solution have been set forth4 ,they depend either on the total decomposition of the copper solution employed by the reducing sugar1 or else on the collection and titration of the cuprous oxid formed in the reaction4 ,in the gravimetric methods the general principle of the process rests upon the collection of the cuprous oxid formed and its reduction to metallic copper1 the weight of which serves as a starting point in the calculations of the weight of reducing sugar1 which has been oxidized in the solution4 ,the factors which affect the weight of copper obtained are essentially those which influence the results in the volumetric method4 ,the composition of the copper solution1 the temperature at which the reduction is accomplished1 the time of heating1 the strength of the sugar solution and the details of the manipulation1 all affect more or less the quantity of copper obtained4 ,as in the volumetric method also1 the kind of reducing sugar must be taken in consideration1 dextrose1 levulose1 invert sugar1 maltose and other sugars having each a definite factor for reduction in given conditions4 ,it follows1 therefore1 that only those results are of value which are obtained under definite conditions1 rigidly controlled4 #acf4 ,gravimetric ,methods of the ,department of ,agriculture ,laboratory4--,the process used in this laboratory is based essentially on the methods of ,maercker1 ,behrend1 ,morgen1 ,meissl1 ,hiller and ,allihn4#aje ,where dextrose alone is present1 the table of factors proposed by ,allihn is used and also the copper solution corresponding thereto4 ,for pure invert sugar1 the tables and solutions of ,meissl are used4 ,for invert sugar in the presence of sucrose1 the table and process proposed by ,hiller are used4 ,illustration3 ,,figure #dc4 ,,apparatus ,,for ,,the ,,electrolytic ,,deposition ,,of ,,copper4 ,the reduction of the copper solution and the electrolytic deposition of the copper are accomplished as follows3 ,the copper and alkali solutions are kept in separate bottles4 ,after mixing the equivalent volume of the two solutions in a beaker1 heat is applied and the mixture boiled4 ,to the boiling liquid the proper volume of the cold sugar solution is added4 ,this must always be less than the amount required for complete reduction4 ,the solution is again brought into ebullition and kept boiling exactly two minutes4 ,a two-minute sand glass is conveniently used to determine the time of boiling4 ,at the end of this time an equal volume of freshly boiled cold water is added1 and the supernatant liquor at once passed through a gooch under pressure4 ,the residual cuprous oxid is covered with boiling water and washed by decantation until the wash water is no longer alkaline4 ,it is more convenient to wash in such a way that1 at the end1 the greater part of the cuprous oxid is in the gooch4 ,the felt and cuprous oxid are then returned to the beaker in which the reduction is made4 ,the gooch is moistened with nitric acid to dissolve any adhering oxid and then is washed into the beaker4 ,enough nitric acid is added to bring all the oxid into solution1 an excess being avoided1 and a small amount of water added4 ,the mixture is again passed under pressure through a gooch having a thin felt1 to remove the asbestos and the filtrate collected in a flask of about #aej cubic centimeters capacity4 ,the washing is continued until the gooch is free of copper1 when the volume of the filtrate should be about #ajj cubic centimeters4 ,the liquid is transferred to a platinum dish holding about #age cubic centimeters and the flask washed with about twenty-five cubic centimeters of water4 ,from three to five cubic centimeters of strong sulfuric acid are added and the copper deposited by an electric current4 #acg4 ,precipitating the ,copper4--,when no more nitric acid is used than indicated in the previous paragraph1 it will not be necessary to remove it by evaporation4 ,the platinum dishes containing the solutions of the cuprous oxid are arranged as shown in the figure for the precipitation of the copper by the electric current4 ,each of the supporting stands has its base covered with sheet-copper1 on which the platinum dishes rest4 ,the uprights are made of heavy glass rods and carry the supports for the platinum cylinders which dip into the copper solutions4 ,the current used is from the city service and is brought in through the lamp shown at the right of the figure4 ,this current has a voltage of about #abj4 ,after passing the lamp it is conducted through the regulator shown at the right1 a glass tube closed below by a stopper carrying a piece of platinum foil1 and above by one holding a glass tube1 in the lower end of which is sealed a piece of sheet platinum connected1 through the glass tube1 with the lamp4 ,the regulating tube contains dilute sulfuric acid4 ,the strength of current desired is secured by adjusting the movable pole4 ,a battery of this kind easily secures the precipitation of sixteen samples at once1 but only twelve are shown in the figure4 ,the practice here is to start the operation at the time of leaving the laboratory in the afternoon4 ,the next morning the deposition of the copper will be found complete4 ,the wiring of the apparatus is shown in the figure4 ,the wire from the regulator is connected with the base of the first stand1 and thence passes through the horizontal support to the base of the second1 and so on4 ,the return to the lamp is accomplished by means of the upper wire4 ,this plan of arranging the apparatus has been used for two years1 and with perfect satisfaction4 ,where a street current is not available1 the following directions may be followed3 ,use four gravity cells1 such as are employed in telegraphic work1 for generating the current4 ,this will be strong enough for one sample and by working longer for two4 ,connect the platinum dish with the zinc pole of the battery4 ,the current is allowed to pass until all the copper is deposited4 ,where a larger number of samples is to be treated at once1 the size of the battery must be correspondingly increased4 #ach4 ,method ,used at the ,halle ,station4--,the method used at the ,halle station is the same as that originally described by ,maercker for dextrose4#ajf ,the copper solution employed is the same as in the allihn method1 viz41 #cd4fd grams of copper sulfate in #ejj cubic centimeters1 and #agc grams of rochelle salt and #abe grams of potassium hydroxid in the same quantity of water4 ,in a porcelain dish are placed thirty cubic centimeters of copper solution and an equal quantity of the alkali1 sixty cubic centimeters of water added and the mixture boiled4 ,to the solution1 in lively ebullition1 are added twenty-five cubic centimeters of the dextrose solution to be examined which must not contain more than one per cent of sugar4 ,the mixture is again boiled and the separated cuprous oxid immediately poured into the filter and washed with hot water1 until the disappearance of an alkaline reaction4 ,for filtering1 a glass tube is employed1 provided with a platinum disk1 and resembling in every respect similar tubes used for the extraction of substances with ether and alcohol4 ,the arrangement of the filtering apparatus is shown in ,fig4 #dd4 ,in the ,halle method it is recommended that the tubes be prepared by introducing a platinum cone in place of the platinum disk and filling it with asbestos felt1 pressing the felt tightly against the sides of the glass tube and making the asbestos fully one centimeter in thickness4 ,this is a much less convenient method of working than the one described above4 ,after filtration and washing1 the cuprous oxid is washed with ether and alcohol and dried for an hour at #aaj1 and finally reduced to metallic copper in a stream of pure dry hydrogen1 heat being applied by means of a small flame4 ,the apparatus for the reduction of the cuprous oxid is shown in ,fig4 #de4 ,the metallic copper1 after cooling and weighing1 is dissolved in nitric acid1 the tube washed with water1 ether and alcohol1 and again dried1 when it is ready for use a second time4 ,the percentage of dextrose is calculated from the milligrams of copper found by ,allihn's table4 ,illustration3 ,,figure #dd4 ,,apparatus ,,for ,,filtering ,,copper ,,suboxid4 ,illustration3 ,,figure #de4 ,,apparatus ,,for ,,reducing ,,copper ,,suboxid4 #aci4 ,tables for ,use in the ,gravimetric ,determination of ,reducing ,sugars4--,the value of a table for computing the percentage of a reducing sugar present in a solution1 is based on the accuracy with which the directions for the determination are followed4 ,the solution must be of the proper strength and made in the way directed4 ,the degree of dilution prescribed must be scrupulously preserved and the methods of boiling during reduction and washing the reduced copper1 followed4 ,the quantity of copper obtained by the use of different alkaline copper solutions and of sugar solutions of a strength different from that allowed by the fixed limits1 is not a safe factor for computation4 ,it must be understood1 therefore1 that in the use of the tables the directions which are given are to be followed in every particular4 #adj4 ,allihn's ,gravimetric ,method for the ,determination of ,dextrose4--,reagents3 ,i4 #cd4fci grams of ,cu,s,o4#e;,h,o1 dissolved in water and diluted to half a liter3 ,,ii4 #agc grams of rochelle salts dissolved in water and diluted #abe grams of ,,koh1 to half a liter4 ,manipulation3 ,place thirty cubic centimeters of the copper solution 7,i71 thirty cubic centimeters of the alkaline tartrate solution 7,,ii71 and sixty cubic centimeters of water in a beaker and heat to boiling4 ,add twenty-five cubic centimeters of the solution of the material to be examined1 which must be so prepared as not to contain more than one per cent of dextrose1 and boil for two minutes4 ,filter immediately after adding an equal volume of recently boiled cold water and obtain the weight of copper by one of the gravimetric methods given4 ,the corresponding weight of dextrose is found by the following table3 ,,allihn',s ,,table ,,for ,,the ,,determination ,,of ,,dextrose4 7,a7 ,milligrams of copper4 7,b7 ,milligrams of dextrose4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #aj #f4a #df #bc4i #hb #da4h #aah #fj4a #aed #gh4f #aa #f4f #dg #bd4d #hc #db4c #aai #fj4f #aee #gi4a #ab #g4a #dh #bd4i #hd #db4h #abj #fa4a #aef #gi4f #ac #g4f #di #be4d #he #dc4d #aba #fa4f #aeg #hj4a #ad #h4a #ej #be4i #hf #dc4i #abb #fb4a #aeh #hj4g #ae #h4f #ea #bf4d #hg #dd4d #abc #fb4f #aei #ha4b #af #i4j #eb #bf4i #hh #dd4i #abd #fc4a #afj #ha4g #ag #i4e #ec #bg4d #hi #de4d #abe #fc4g #afa #hb4b #ah #aj4j #ed #bg4i #ij #de4i #abf #fd4b #afb #hb4g #ai #aj4e #ee #bh4d #ia #df4d #abg #fd4g #afc #hc4c #bj #aa4j #ef #bh4h #ib #df4i #abh #fe4b #afd #hc4h #ba #aa4e #eg #bi4c #ic #dg4d #abi #fe4g #afe #hd4c #bb #ab4j #eh #bi4h #id #dg4i #acj #ff4b #aff #hd4h #bc #ab4e #ei #cj4c #ie #dh4d #aca #ff4g #afg #he4c #bd #ac4j #fj #cj4h #if #dh4i #acb #fg4b #afh #he4i #be #ac4e #fa #ca4c #ig #di4d #acc #fg4g #afi #hf4d #bf #ad4j #fb #ca4h #ih #di4i #acd #fh4b #agj #hf4i #bg #ad4e #fc #cb4c #ii #ej4d #ace #fh4h #aga #hg4d #bh #ae4j #fd #cb4h #ajj #ej4i #acf #fi4c #agb #hg4i #bi #ae4e #fe #cc4c #aja #ea4d #acg #fi4h #agc #hh4e #cj #af4j #ff #cc4h #ajb #ea4i #ach #gj4c #agd #hi4j #ca #af4e #fg #cd4c #ajc #eb4d #aci #gj4h #age #hi4e #cb #ag4j #fh #cd4h #ajd #eb4i #adj #ga4c #agf #ij4j #cc #ag4e #fi #ce4c #aje #ec4e #ada #ga4h #agg #ij4e #cd #ah4j #gj #ce4h #ajf #ed4j #adb #gb4c #agh #ia4a #ce #ah4e #ga #cf4c #ajg #ed4e #adc #gb4i #agi #ia4f #cf #ah4i #gb #cf4h #ajh #ee4j #add #gc4d #ahj #ib4a #cg #ai4d #gc #cg4c #aji #ee4e #ade #gc4i #aha #ib4f #ch #ai4i #gd #cg4h #aaj #ef4j #adf #gd4d #ahb #ic4a #ci #bj4d #ge #ch4c #aaa #ef4e #adg #gd4i #ahc #ic4g #dj #bj4i #gf #ch4h #aab #eg4j #adh #ge4e #ahd #id4b #da #ba4d #gg #ci4c #aac #eg4e #adi #gf4j #ahe #id4g #db #ba4i #gh #ci4h #aad #eh4j #aej #gf4e #ahf #ie4b #dc #bb4d #gi #dj4c #aae #eh4f #aea #gg4j #ahg #ie4g #dd #bb4i #hj #dj4h #aaf #ei4a #aeb #gg4e #ahh #if4c #de #bc4d #ha #da4c #aag #ei4f #aec #gh4a #ahi #if4h 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #aij #ig4c #bcc #abj4a #bgf #adc4c #cai #afg4j #cfb #aia4a #aia #ig4h #bcd #abj4g #bgg #adc4i #cbj #afg4e #cfc #aia4g #aib #ih4d #bce #aba4b #bgh #add4d #cba #afh4a #cfd #aib4c #aic #ih4i #bcf #aba4g #bgi #ade4j #cbb #afh4f #cfe #aib4i #aid #ii4d #bcg #abb4c #bhj #ade4e #cbc #afi4b #cff #aic4d #aie #ajj4j #bch #abb4h #bha #adf4a #cbd #afi4g #cfg #aid4j #aif #ajj4e #bci #abc4d #bhb #adf4f #cbe #agj4c #cfh #aid4f #aig #aja4j #bdj #abc4i #bhc #adg4b #cbf #agj4i #cfi #aie4a #aih #aja4e #bda #abd4d #bhd #adg4g #cbg #aga4d #cgj #aie4g #aii #ajb4j #bdb #abe4j #bhe #adh4c #cbh #agb4j #cga #aif4c #bjj #ajb4f #bdc #abe4e #bhf #adh4h #cbi #agb4e #cgb #aif4h #bja #ajc4a #bdd #abf4j #bhg #adi4e #ccj #agc4a #cgc #aig4d #bjb #ajc4g #bde #abf4f #bhh #adi4d #cca #agc4g #cgd #aih4j #bjc #ajd4b #bdf #abg4a #bhi #aej4i #ccb #agd4b #cge #aih4f #bjd #ajd4g #bdg #abg4f #bij #aea4j #ccc #agd4h #cgf #aii4a #bje #aje4c #bdh #abh4a #bia #aea4f #ccd #age4c #cgg #aii4g #bjf #aje4h #bdi #abh4g #bib #aeb4a #cce #age4i #cgh #bjj4c #bjg #ajf4c #bej #abi4b #bic #aeb4g #ccf #agf4e #cgi #bjj4h #bjh #ajf4h #bea #abi4g #bid #aec4b #ccg #agg4j #chj #bja4d #bji #ajg4d #beb #acj4c #bie #aec4h #cch #agg4f #cha #bjb4j #baj #ajg4i #bec #acj4h #bif #aed4c #cci #agh4a #chb #bjb4e #baa #ajh4d #bed #aca4d #big #aed4i #cdj #agh4g #chc #bjc4a #bab #aji4j #bee #aca4i #bih #aee4d #cda #agi4c #chd #bjc4g #bac #aji4e #bef #acb4d #bii #aef4j #cdb #agi4h #che #bjd4c #bad #aaj4j #beg #acc4j #cjj #aef4e #cdc #ahj4d #chf #bjd4h #bae #aaj4f #beh #acc4e #cja #aeg4a #cdd #ahj4i #chg #bje4d #baf #aaa4a #bei #acd4a #cjb #aeg4f #cde #aha4e #chh #bjf4j #bag #aaa4f #bfj #acd4f #cjc #aeh4b #cdf #ahb4a #chi #bjf4e #bah #aab4a #bfa #ace4a #cjd #aeh4g #cdg #ahb4f #cij #bjg4a #bai #aab4g #bfb #ace4g #cje #aei4c #cdh #ahc4b #cia #bjg4g #bbj #aac4b #bfc #acf4b #cjf #aei4h #cdi #ahc4g #cib #bjh4c #bba #aac4g #bfd #acf4h #cjg #afj4d #cej #ahd4c #cic #bjh4h #bbb #aad4c #bfe #acg4c #cjh #afj4i #cea #ahd4i #cid #bji4d #bbc #aad4h #bff #acg4h #cji #afa4e #ceb #ahe4d #cie #baj4j #bbd #aae4c #bfg #ach4d #caj #afb4j #cec #ahf4j #cif #baj4f #bbe #aae4i #bfh #ach4i #caa #afb4f #ced #ahf4f #cig #baa4b #bbf #aaf4d #bfi #aci4e #cab #afc4a #cee #ahg4b #cih #baa4g #bbg #aaf4i #bgj #adj4j #cac #afc4g #cef #ahg4g #cii #bab4c #bbh #aag4d #bga #adj4f #cad #afd4b #ceg #ahh4c #djj #bab4i #bbi #aah4j #bgb #ada4a #cae #afd4h #ceh #ahh4i #dja #bac4e #bcj #aah4e #bgc #ada4g #caf #afe4c #cei #ahi4d #djb #bad4a #bca #aai4j #bgd #adb4b #cag #afe4i #cfj #aij4j #djc #bad4f #bcb #aai4f #bge #adb4h #cah #aff4d #cfa #aij4f #djd #bae4b 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #dje #bae4h #dag #bbb4h #dbi #bbi4h #dda #bcf4i #dec #bdd4j #djf #baf4d #dah #bbc4c #dcj #bcj4d #ddb #bcg4e #ded #bdd4f #djg #bag4j #dai #bbc4i #dca #bca4j #ddc #bch4a #dee #bde4b #djh #bag4e #dbj #bbd4e #dcb #bca4f #ddd #bch4g #def #bde4g #dji #bah4a #dba #bbe4a #dcc #bcb4b #dde #bci4c #deg #bdf4c #daj #bah4g #dbb #bbe4g #dcd #bcb4h #ddf #bci4h #deh #bdf4i #daa #bai4c #dbc #bbf4c #dce #bcc4d #ddg #bdj4d #dei #bdg4e #dab #bai4i #dbd #bbf4i #dcf #bcc4i #ddh #bda4j #dfj #bdh4a #dac #bbj4d #dbe #bbg4e #dcg #bcd4e #ddi #bda4f #dfa #bdh4g #dad #bba4j #dbf #bbh4j #dch #bce4a #dej #bdb4b #dfb #bdi4c #dae #bba4f #dbg #bbh4f #dci #bce4g #dea #bdb4h #dfc #bdi4i #daf #bbb4b #dbh #bbi4b #ddj #bcf4c #deb #bdc4d #ada4 ,meissl's ,table for ,invert ,sugar4--,invert sugar is usually the product of the hydrolysis of sucrose4 ,the following table is to be used when the hydrolysis is complete1 i4 e41 when no sucrose is left in the solution4 ,the solution of copper sulfate and of the alkaline tartrate are made up as follows3 #cd4fd grams of copper sulfate in half a liter1 and #agc grams of rochelle salt and #ea4f grams sodium hydroxid in the same volume4 ,the quantity of sugar solution used must not contain more than #bde nor less than ninety milligrams of invert sugar4 ,in the determination twenty-five cubic centimeters of the copper solution and an equal volume of the alkaline tartrate are mixed and boiled1 the proper amount of sugar solution added to secure a quantity of invertose within the limits named1 the volume completed to #ajj cubic centimeters with boiling water1 and the mixture kept in lively ebullition for two minutes4 ,an equal volume of recently boiled cold water is added and the cuprous oxid at once separated by filtration on asbestos under pressure1 and washed free of alkali with boiling water4 ,the metallic copper is secured by one of the methods already described4 ,,table ,,for ,,invert ,,sugar ,,by ,,meissl ,,and ,,wien4#ajg 7,a7 ,milligrams of copper4 7,b7 ,milligrams of invert sugar4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ij #df4i #acc #fi4g #agf #ic4j #bai #aag4j #ia #dg4d #acd #gj4c #agg #ic4e #bbj #aag4e #ib #dg4i #ace #gj4h #agh #id4a #bba #aah4a #ic #dh4d #acf #ga4c #agi #id4f #bbb #aah4g #id #dh4i #acg #ga4i #ahj #ie4b #bbc #aai4b #ie #di4e #ach #gb4d #aha #ie4g #bbd #aai4h #if #ej4j #aci #gb4i #ahb #if4b #bbe #abj4d #ig #ej4e #adj #gc4e #ahc #if4h #bbf #abj4i #ih #ea4a #ada #gd4j #ahd #ig4c #bbg #aba4e #ii #ea4f #adb #gd4e #ahe #ig4h #bbh #abb4a #ajj #eb4a #adc #ge4a #ahf #ih4d #bbi #abb4f #aja #eb4g #add #ge4f #ahg #ii4j #bcj #abc4b #ajb #ec4b #ade #gf4a #ahh #ii4e #bca #abc4h #ajc #ec4g #adf #gf4g #ahi #ajj4a #bcb #abd4c #ajd #ed4c #adg #gg4b #aij #ajj4f #bcc #abd4i #aje #ed4h #adh #gg4h #aia #aja4b #bcd #abe4e #ajf #ee4c #adi #gh4c #aib #aja4g #bce #abf4j #ajg #ee4i #aej #gh4i #aic #ajb4c #bcf #abf4f #ajh #ef4d #aea #gi4d #aid #ajb4i #bcg #abg4b #aji #ef4i #aeb #hj4j #aie #ajc4d #bch #abg4h #aaj #eg4e #aec #hj4e #aif #ajd4j #bci #abh4c #aaa #eh4j #aed #ha4j #aig #ajd4f #bdj #abh4i #aab #eh4e #aee #ha4f #aih #aje4a #bda #abi4e #aac #ei4a #aef #hb4a #aii #aje4g #bdb #acj4j #aad #ei4f #aeg #hb4g #bjj #ajf4c #bdc #acj4f #aae #fj4a #aeh #hc4b #bja #ajf4h #bdd #aca4b #aaf #fj4g #aei #hc4h #bjb #ajg4d #bde #aca4h #aag #fa4b #afj #hd4c #bjc #ajg4i #bdf #acb4c #aah #fa4g #afa #hd4h #bjd #ajh4e #bdg #acb4i #aai #fb4c #afb #he4d #bje #aji4a #bdh #acc4e #abj #fb4h #afc #he4i #bjf #aji4f #bdi #acd4a #aba #fc4c #afd #hf4e #bjg #aaj4b #bej #acd4f #abb #fc4i #afe #hg4j #bjh #aaj4h #bea #ace4b #abc #fd4d #aff #hg4f #bji #aaa4c #beb #ace4h #abd #fd4i #afg #hh4a #baj #aaa4i #bec #acf4c #abe #fe4e #afh #hh4f #baa #aab4e #bed #acf4i #abf #ff4j #afi #hi4b #bab #aac4j #bee #acg4e #abg #ff4e #agj #hi4g #bac #aac4f #bef #ach4a #abh #fg4a #aga #ij4c #bad #aad4b #beg #ach4f #abi #fg4f #agb #ij4h #bae #aad4g #beh #aci4b #acj #fh4a #agc #ia4d #baf #aae4c #bei #aci4h #aca #fh4g #agd #ia4i #bag #aae4h #bfj #adj4d #acb #fi4b #age #ib4d #bah #aaf4d #bfa #adj4i 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #bfb #ada4e #cje #aff4h #cdh #aib4f #cia #bai4c #bfc #adb4a #cjf #afg4c #cdi #aic4b #cib #bai4i #bfd #adb4g #cjg #afg4i #cej #aic4h #cic #bbj4e #bfe #adc4b #cjh #afh4e #cea #aid4d #cid #bba4b #bff #adc4h #cji #afi4a #ceb #aie4j #cie #bba4h #bfg #add4d #caj #afi4g #cec #aie4f #cif #bbb4d #bfh #add4i #caa #agj4c #ced #aif4b #cig #bbc4a #bfi #ade4e #cab #agj4i #cee #aif4h #cih #bbc4g #bgj #adf4a #cac #aga4e #cef #aig4d #cii #bbd4c #bga #adf4g #cad #agb4a #ceg #aih4j #djj #bbd4i #bgb #adg4b #cae #agb4g #ceh #aih4f #dja #bbe4g #bgc #adg4h #caf #agc4c #cei #aii4b #djb #bbf4d #bgd #adh4d #cag #agc4i #cfj #aii4h #djc #bbg4a #bge #adi4j #cah #agd4e #cfa #bjj4d #djd #bbg4h #bgf #adi4e #cai #age4a #cfb #bja4a #dje #bbh4f #bgg #aej4a #cbj #age4f #cfc #bja4g #djf #bbi4c #bgh #aej4g #cba #agf4b #cfd #bjb4c #djg #bcj4j #bgi #aea4c #cbb #agf4h #cfe #bjc4j #djh #bcj4g #bhj #aea4i #cbc #agg4d #cff #bjc4f #dji #bca4d #bha #aeb4e #cbd #agh4j #cfg #bjd4b #daj #bcb4a #bhb #aec4a #cbe #agh4f #cfh #bjd4h #daa #bcb4h #bhc #aec4g #cbf #agi4b #cfi #bje4e #dab #bcc4e #bhd #aed4c #cbg #agh4h #cgj #bjf4a #dac #bcd4c #bhe #aed4i #cbh #ahj4d #cga #bjf4g #dad #bce4j #bhf #aee4e #cbi #aha4j #cgb #bjg4c #dae #bce4g #bhg #aef4a #ccj #aha4f #cgc #bjh4j #daf #bcf4d #bhh #aef4g #cca #ahb4b #cgd #bjh4f #dag #bcg4a #bhi #aeg4b #ccb #ahb4h #cge #bji4b #dah #bcg4h #bij #aeg4h #ccc #ahc4e #cgf #bji4i #dai #bch4e #bia #aeh4d #ccd #ahd4a #cgg #baj4e #dbj #bci4b #bib #aei4j #cce #ahd4g #cgh #baa4a #dba #bci4i #bic #aei4f #ccf #ahe4d #cgi #baa4g #dbb #bdj4f #bid #afj4b #ccg #ahf4j #chj #bab4d #dbc #bda4c #bie #afj4h #cch #ahf4f #cha #bac4j #dbd #bdb4j #bif #afa4d #cci #ahg4b #chb #bac4f #dbe #bdb4g #big #afb4j #cdj #ahg4h #chc #bad4c #dbf #bdc4d #bih #afb4f #cda #ahh4d #chd #bad4i #dbg #bdd4a #bii #afc4b #cdb #ahi4j #che #bae4e #dbh #bdd4i #cjj #afc4h #cdc #ahi4f #chf #baf4a #dbi #bde4f #cja #afd4d #cdd #aij4b #chg #baf4h #dcj #bdf4c #cjb #afe4j #cde #aij4h #chh #bag4d #cjc #afe4f #cdf #aia4d #chi #bah4j #cjd #aff4b #cdg #aib4j #cij #bah4g #adb4 ,table for the ,determination of ,invert ,sugar 7,reducing ,sugars7 in the ,presence of ,sucrose4--,the method adopted by the ,association of ,official ,agricultural ,chemists is essentially that proposed by ,meissl and ,hiller4#ajh ,prepare a solution of the material to be examined in such a manner that it contains twenty grams of the mixed sugars in one hundred cubic centimeters1 after clarification and the removal of the excess of lead4 ,prepare a series of solutions in large test tubes by adding one1 two1 three1 four1 five etc4 cubic centimeters of this solution to each tube successively4 ,add five cubic centimeters of the mixed copper reagent to each1 heat to boiling1 boil two minutes and filter4 ,note the volume of sugar solution which gives the filtrate lightest in tint1 but still distinctly blue4 ,place twenty times this volume of the sugar solution in a #ajj cubic centimeter flask1 dilute to the mark1 and mix well4 ,use fifty cubic centimeters of the solution for the determination1 which is conducted as already described1 until the weight of copper is obtained4 ,for the calculation of the results use the following formulas and table of factors of ,meissl and ,hiller3#aji ,let ,cu the weight of the copper obtained2 ,p the polarization of the sample2 ,w the weight of the sample in the fifty cubic centimeters of the solution used for determination2 ,f the factor obtained from the table for conversion of copper to invert sugar2 ,cu ---- approximate absolute weight of invert sugar ,z2 #b #ajj ,z ----- approximate per cent of invert sugar y2 ,w #ajj,p ------- ,r1 relative number for sucrose2 ,p y #ajj - ,r ,i1 relative number for invert sugar2 ,cu ---- per cent of invert sugar4 ,w ,z indicates the vertical column1 and the ratio of ,r to ,i1 the horizontal column of the table1 which are to be used for the purpose of finding the factor 7,f7 for calculating copper to invert sugar4 ,example3--,the polarization of a sugar is #hf4d1 and #c4bef grams of it 7,w7 are equivalent to #j4bij gram of copper4 ,then3 ,cu #j4bij ---- ----- #j4ade ,z #b #b #ajj #ajj ,z ----- #j4ade ------ #d4de y ,w #c4bef #ajj,p #hfdj -------- ------------ #ie4a ,r ,p y #hf4d #d4de #ajj - ,r #ajj - #ie4a #d4i ,i ,r 3 ,i #ie4a 3 #d4i ,by consulting the table it will be seen that the vertical column headed ,i #aej is nearest to ,z1 #ade1 the horizontal column headed #ie3 #e is nearest to the ratio of ,r to ,i1 #ie4a3 #d4i4 ,where these columns meet we find the factor #ea4b1 which enters into the final calculation3 ,cu,f 4#bij #ea4b ----- ------------- #d4ef the true per cent of invert sugar4 ,w #c4bef ,,meissl ,,and ,,hiller',s ,,factors ,,for ,,the ,,determination ,,of ,,more ,,than ,,one ,,per ,,cent ,,of ,,invert ,,sugar4 ,ratio of ,approximate absolute weight of invert sugar ,z4 sucrose ,i ,i ,i ,i ,i ,i ,i to invert #bjj #age #aej #abe #ajj #ge #ej sugar mg4 mg4 mg4 mg4 mg4 mg4 mg4 ,r 3 ,i4 #j 3 #ajj #ef4d #ee4d #ed4e #ec4h #ec4b #ec4j #ec4j #aj 3 #ij #ef4c #ee4c #ed4d #ec4h #ec4b #eb4i #eb4i #bj 3 #hj #ef4b #ee4b #ed4c #ec4g #ec4b #eb4g #eb4g #cj 3 #gj #ef4a #ee4a #ed4b #ec4g #ec4b #eb4f #eb4f #dj 3 #fj #ee4i #ee4j #ed4a #ec4f #ec4a #eb4e #eb4d #ej 3 #ej #ee4g #ed4i #ed4j #ec4e #ec4a #eb4c #eb4b #fj 3 #dj #ee4f #ed4g #ec4h #ec4b #eb4h #eb4a #ea4i #gj 3 #cj #ee4e #ed4e #ec4e #eb4i #eb4e #ea4i #ea4f #hj 3 #bj #ee4d #ed4c #ec4c #eb4g #eb4b #ea4g #ea4c #ij 3 #aj #ed4f #ec4f #ec4a #eb4f #eb4a #ea4f #ea4b #ia 3 #i #ed4a #ec4f #eb4f #eb4a #ea4f #ea4b #ej4g #ib 3 #h #ec4f #ec4a #eb4a #ea4f #ea4b #ej4g #ej4c #ic 3 #g #ec4f #ec4a #eb4a #ea4b #ej4g #ej4c #di4h #id 3 #f #ec4a #eb4f #ea4f #ej4g #ej4c #di4h #dh4i #ie 3 #e #eb4f #eb4a #ea4b #ej4c #di4d #dh4i #dh4e #if 3 #d #eb4a #ea4b #ej4g #di4h #dh4i #dg4g #df4i #ig 3 #c #ej4g #ej4c #di4h #dh4i #dg4g #df4b #de4a #ih 3 #b #di4i #dh4i #dh4e #dg4c #de4h #dc4c #dj4j #ii 3 #a #dg4g #dg4c #df4e #de4a #dc4c #da4b #ch4a #adc4 ,table for the ,estimation of ,milk ,sugar4--,the solutions to be used for this table are the same as those employed in the preceding table for the estimation of invert sugar4 ,the milk sugar is supposed to be in a pure form in solution before beginning the analysis4 ,the method to be employed for milk will be given in the part devoted to dairy products4 ,in the conduct of the work twenty-five cubic centimeters of the copper solution are mixed with an equal quantity of the alkaline tartrate mixture1 and from twenty to one hundred cubic centimeters of the sugar solution added1 according to its concentration4 ,this solution should not contain less than seventy nor more than #cjf milligrams of lactose4 ,the volume is completed to #aej cubic centimeters with boiling water and kept in lively ebullition for six minutes4 ,the rest of the operation is conducted in the manner already described4 ,from the weight of copper obtained the quantity of milk sugar is determined by inspecting the table4 ,it is recommended to use such a weight of milk sugar as will give about #bjj milligrams of copper4 ,,table ,,for ,,determining ,,milk ,,sugar4 7,a7 ,milligrams of copper4 7,b7 ,milligrams of milk sugar4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ajj #ga4f #abj #hf4d #adj #aja4c #afj #aaf4d #aja #gb4d #aba #hg4b #ada #ajb4j #afa #aag4a #ajb #gc4a #abb #hg4i #adb #ajb4h #afb #aag4i #ajc #gc4h #abc #hh4g #adc #ajc4e #afc #aah4f #ajd #gd4f #abd #hi4d #add #ajd4c #afd #aai4d #aje #ge4c #abe #ij4a #ade #aje4a #afe #abj4b #ajf #gf4a #abf #ij4i #adf #aje4h #aff #abj4i #ajg #gf4h #abg #ia4f #adg #ajf4f #afg #aba4g #ajh #gg4f #abh #ib4d #adh #ajg4c #afh #abb4d #aji #gh4c #abi #ic4a #adi #ajh4a #afi #abc4b #aaj #gi4j #acj #ic4h #aej #ajh4h #agj #abc4i #aaa #gi4h #aca #id4f #aea #aji4f #aga #abd4g #aab #hj4e #acb #ie4c #aeb #aaj4c #agb #abe4e #aac #ha4c #acc #if4a #aec #aaa4a #agc #abf4b #aad #hb4j #acd #if4i #aed #aaa4i #agd #abg4j #aae #hb4g #ace #ig4f #aee #aab4f #age #abg4h #aaf #hc4e #acf #ih4c #aef #aac4d #agf #abh4e #aag #hd4b #acg #ii4a #aeg #aad4a #agg #abi4c #aah #he4j #ach #ii4h #aeh #aad4i #agh #acj4a #aai #he4g #aci #ajj4e #aei #aae4f #agi #acj4h 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ahj #aca4f #bbc #afd4b #bff #aig4b #cji #bca4d #aha #acb4d #bbd #afd4i #bfg #aih4j #caj #bcb4b #ahb #acc4a #bbe #afe4g #bfh #aih4h #caa #bcb4i #ahc #acc4i #bbf #aff4d #bfi #aii4e #cab #bcc4g #ahd #acd4g #bbg #afg4b #bgj #bjj4c #cac #bcd4e #ahe #ace4d #bbh #afg4i #bga #bja4a #cad #bce4c #ahf #acf4b #bbi #afh4f #bgb #bja4i #cae #bcf4a #ahg #acg4j #bcj #afi4d #bgc #bjb4g #caf #bcf4h #ahh #acg4g #bca #agj4a #bgd #bjc4e #cag #bcg4f #ahi #ach4e #bcb #agj4i #bge #bjd4c #cah #bch4d #aij #aci4c #bcc #aga4f #bgf #bje4a #cai #bci4b #aia #adj4j #bcd #agb4d #bgg #bje4i #cbj #bdj4j #aib #adj4h #bce #agc4a #bgh #bjf4g #cba #bdj4g #aic #ada4f #bcf #agc4i #bgi #bjg4e #cbb #bda4e #aid #adb4c #bcg #agd4f #bhj #bjh4c #cbc #bdb4c #aie #adc4a #bch #age4d #bha #bji4a #cbd #bdc4a #aif #adc4i #bci #agf4b #bhb #bji4i #cbe #bdc4i #aig #add4f #bdj #agf4i #bhc #baj4g #cbf #bdd4f #aih #ade4d #bda #agg4g #bhd #baa4e #cbg #bde4d #aii #adf4b #bdb #agh4e #bhe #bab4c #cbh #bdf4b #bjj #adf4i #bdc #agi4c #bhf #bac4a #cbi #bdg4j #bja #adg4g #bdd #ahj4a #bhg #bac4i #ccj #bdg4g #bjb #adh4e #bde #ahj4h #bhh #bad4g #cca #bdh4e #bjc #adi4b #bdf #aha4f #bhi #bae4e #ccb #bdi4b #bjd #aej4j #bdg #ahb4d #bij #baf4c #ccc #bej4j #bje #aej4g #bdh #ahc4b #bia #bag4a #ccd #bej4h #bjf #aea4e #bdi #ahd4j #bib #bag4i #cce #bea4f #bjg #aeb4b #bej #ahd4h #bic #bah4g #ccf #beb4e #bjh #aec4j #bea #ahe4e #bid #bai4e #ccg #bec4c #bji #aec4g #beb #ahf4c #bie #bbj4c #cch #bed4a #baj #aed4e #bec #ahg4a #bif #bba4a #cci #bed4i #baa #aee4b #bed #ahg4i #big #bba4i #cdj #bee4g #bab #aef4j #bee #ahh4g #bih #bbb4g #cda #bef4e #bac #aef4g #bef #ahi4d #bii #bbc4e #cdb #beg4d #bad #aeg4e #beg #aij4b #cjj #bbd4d #cdc #beh4b #bae #aeh4b #beh #aia4j #cja #bbe4b #cdd #bei4j #baf #aei4j #bei #aia4h #cjb #bbe4i #cde #bei4h #bag #aei4g #bfj #aib4e #cjc #bbf4g #cdf #bfj4f #bah #afj4d #bfa #aic4c #cjd #bbg4e #cdg #bfa4d #bai #afa4b #bfb #aid4a #cje #bbh4c #cdh #bfb4c #bbj #afa4i #bfc #aid4i #cjf #bbi4a #cdi #bfc4a #bba #afb4g #bfd #aie4g #cjg #bbi4h #cej #bfc4i #bbb #afc4d #bfe #aif4d #cjh #bcj4f #cea #bfd4g 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ceb #bfe4e #cfe #bgf4b #cgg #bhf4e #chi #bif4h #cec #bff4c #cff #bgg4a #cgh #bhg4d #cij #big4g #ced #bfg4b #cfg #bgg4i #cgi #bhh4b #cia #bih4e #cee #bfh4j #cfh #bgh4h #chj #bhi4a #cib #bii4d #cef #bfh4h #cfi #bgi4f #cha #bhi4i #cic #cjj4c #ceg #bfi4f #cgj #bhj4e #chb #bij4h #cid #cja4a #ceh #bgj4d #cga #bha4d #chc #bia4g #cie #cjb4j #cei #bga4b #cgb #bhb4b #chd #bib4e #cif #cjb4h #cfj #bgb4a #cgc #bhc4a #che #bic4d #cig #cjc4g #cfa #bgb4i #cgd #bhc4i #chf #bid4b #cih #cjd4f #cfb #bgc4g #cge #bhd4h #chg #bie4a #cii #cje4d #cfc #bgd4e #cgf #bhe4g #chh #bif4j #djj #cjf4c #cfd #bge4c #add4 ,table for the ,determination of ,maltose4--,the copper and alkaline solutions employed for the oxidation of maltose are the same as those used for invert and milk sugars4 ,in the manipulation twenty-five cubic centimeters each of the copper and alkali solutions are mixed and boiled and an equal volume of the maltose solution added1 which should not contain more than one per cent of the sugar4 ,the boiling is continued for four minutes1 an equal volume of cold recently boiled water added1 the cuprous oxid separated by filtration and the metallic copper obtained in the manner already described4 ,the weight of maltose oxidized is then ascertained from the table4 ,example4 ,weight of impure maltose taken1 ten grams to a liter3 ,quantity used1 twenty-five cubic centimeters3 ,weight of copper obtained #bfh milligrams3 ,weight of maltose oxidized #bcg milligrams3 ,weight of impure maltose taken #bej milligrams3 ,percentage of maltose in sample #id4h4 ,,table ,,for ,,maltose4 7,a7 ,milligrams of copper4 7,b7 ,milligrams of maltose4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #cj #be4c #ce #bi4f #dj #cc4i #de #ch4c #ca #bf4a #cf #cj4e #da #cd4h #df #ci4a #cb #bg4j #cg #ca4c #db #ce4g #dg #dj4j #cc #bg4i #ch #cb4b #dc #cf4e #dh #dj4i #cd #bh4g #ci #cc4a #dd #cg4d #di #da4h 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ej #db4f #id #ha4b #ach #abj4f #ahb #afj4a #ea #dc4e #ie #hb4a #aci #aba4e #ahc #afj4i #eb #dd4d #if #hc4j #adj #abb4d #ahd #afa4h #ec #de4b #ig #hc4i #ada #abc4c #ahe #afb4g #ed #df4a #ih #hd4h #adb #abd4b #ahf #afc4f #ee #dg4j #ii #he4g #adc #abe4a #ahg #afd4e #ef #dg4h #ajj #hf4f #add #abf4j #ahh #afe4d #eg #dh4g #aja #hg4e #ade #abf4i #ahi #aff4c #eh #di4f #ajb #hh4d #adf #abg4h #aij #afg4b #ei #ej4d #ajc #hi4b #adg #abh4g #aia #afh4a #fj #ea4c #ajd #ij4a #adh #abi4f #aib #afi4j #fa #eb4b #aje #ia4j #adi #acj4e #aic #afi4h #fb #ec4a #ajf #ia4i #aej #aca4d #aid #agj4g #fc #ec4i #ajg #ib4h #aea #acb4c #aie #aga4f #fd #ed4h #ajh #ic4g #aeb #acc4b #aif #agb4e #fe #ee4g #aji #id4f #aec #acd4a #aig #agc4d #ff #ef4f #aaj #ie4e #aed #ace4j #aih #agd4c #fg #eg4d #aaa #if4d #aee #ace4i #aii #age4b #fh #eh4c #aab #ig4c #aef #acf4h #bjj #agf4a #fi #ei4b #aac #ih4a #aeg #acg4g #bja #agg4j #gj #fj4a #aad #ii4j #aeh #ach4f #bjb #agg4i #ga #fa4j #aae #ii4i #aei #aci4e #bjc #agh4g #gb #fa4h #aaf #ajj4h #afj #adj4d #bjd #agi4f #gc #fb4g #aag #aja4g #afa #ada4c #bje #ahj4e #gd #fc4f #aah #ajb4f #afb #adb4b #bjf #aha4d #ge #fd4e #aai #ajc4e #afc #adc4a #bjg #ahb4c #gf #fe4d #abj #ajd4d #afd #add4j #bjh #ahc4b #gg #ff4b #aba #aje4c #afe #add4i #bji #ahd4a #gh #fg4a #abb #ajf4b #aff #ade4h #baj #ahe4j #gi #fh4j #abc #ajg4a #afg #adf4g #baa #ahe4i #hj #fh4i #abd #ajh4j #afh #adg4f #bab #ahf4h #ha #fi4g #abe #ajh4i #afi #adh4e #bac #ahg4g #hb #gj4f #abf #aji4h #agj #adi4d #bad #ahh4f #hc #ga4e #abg #aaj4g #aga #aej4c #bae #ahi4e #hd #gb4d #abh #aaa4f #agb #aea4b #baf #aij4d #he #gc4b #abi #aab4e #agc #aeb4j #bag #aia4b #hf #gd4a #acj #aac4d #agd #aeb4i #bah #aib4a #hg #ge4j #aca #aad4c #age #aec4h #bai #aic4j #hh #ge4i #acb #aae4b #agf #aed4g #bbj #aic4i #hi #gf4h #acc #aaf4a #agg #aee4f #bba #aid4h #ij #gg4g #acd #aag4j #agh #aef4e #bbb #aie4g #ia #gh4f #ace #aag4i #agi #aeg4d #bbc #aif4f #ib #gi4e #acf #aah4h #ahj #aeh4c #bbd #aig4e #ic #hj4c #acg #aai4g #aha #aei4b #bbe #aih4d 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #bbf #aii4c #bde #baf4c #bfd #bcc4d #bhc #bej4d #bbg #bjj4b #bdf #bag4b #bfe #bcd4c #bhd #bea4c #bbh #bja4a #bdg #bah4a #bff #bce4b #bhe #beb4b #bbi #bjb4j #bdh #bai4j #bfg #bcf4a #bhf #bec4a #bcj #bjb4i #bdi #bai4i #bfh #bcg4j #bhg #bed4j #bca #bjc4h #bej #bbj4h #bfi #bcg4i #bhh #bed4i #bcb #bjd4g #bea #bba4g #bgj #bch4h #bhi #bee4h #bcc #bje4f #beb #bbb4f #bga #bci4g #bij #bef4f #bcd #bjf4e #bec #bbc4e #bgb #bdj4f #bia #beg4e #bce #bjg4d #bed #bbd4d #bgc #bda4e #bib #beh4d #bcf #bjh4c #bee #bbe4c #bgd #bdb4d #bic #bei4c #bcg #bji4a #bef #bbf4b #bge #bdc4c #bid #bfj4b #bch #baj4j #beg #bbg4a #bgf #bdd4b #bie #bfa4a #bci #baj4i #beh #bbh4j #bgg #bde4a #bif #bfb4j #bdj #baa4h #bei #bbh4i #bgh #bdf4j #big #bfb4h #bda #bab4g #bfj #bbi4h #bgi #bdf4i #bih #bfc4g #bdb #bac4f #bfa #bcj4g #bhj #bdg4h #bii #bfd4f #bdc #bad4e #bfb #bca4f #bha #bdh4g #cjj #bfe4e #bdd #bae4d #bfc #bcb4e #bhb #bdi4f #ade4 ,preparation of ,levulose4--,it is not often that levulose1 unmixed with other reducing sugars1 is brought to the attention of the analyst4 ,it probably does not exist in the unmixed state in any agricultural product4 ,the easiest method of preparing it is by the hydrolysis of inulin4 ,a nearly pure levulose has also lately been placed on the market under the name of diabetin4 ,it is prepared from invert sugar4 ,inulin is prepared from dahlia bulbs by boiling the pulp with water and a trace of calcium carbonate4 ,the extract is concentrated to a sirup and subjected to a freezing temperature to promote the crystallization of the inulin4 ,the separated product is subjected to the above operations several times until it is pure and colorless4 ,it is then washed with alcohol and ether and is reduced to a fine powder4 ,before the repeated treatment with water it is advisable to clarify the solution with lead subacetate4 ,the lead is afterwards removed by hydrogen sulfid and the resultant acetic acid neutralized with calcium carbonate4 ,by the action of hot dilute acids inulin is rapidly converted into levulose4 ,levulose may also be prepared from invert sugar1 but in this case it is difficult to free it from traces of dextrose4 ,the most successful method consists in forming a lime compound with the invert sugar and separating the lime levulosate and dextrosate by their difference in solubility4 ,the levulose salt is much less soluble than the corresponding compound of dextrose4 ,in the manufacture of levulose from beet molasses1 the latter is dissolved in six times its weight of water and inverted with a quantity of hydrochloric acid1 proportioned to the quantity of ash present in the sample4 ,after inversion the mixture is cooled to zero and the levulose precipitated by adding fine-ground lime4 ,the dextrose and coloring matters in these conditions are not thrown down4 ,the precipitated lime levulosate is separated by filtration and washed with ice-cold water4 ,the lime salt is afterwards beaten to a cream with water and decomposed by carbon dioxid4 ,the levulose1 after filtration1 is concentrated to the crystallizing point4#aaj #adf4 ,estimation of ,levulose4--,levulose1 when free of any admixture with other reducing sugars1 may be determined by the copper method with the use of the subjoined table1 prepared by ,lehmann4#aaa ,the copper solution is the same as that used for invert sugar1 viz41 #fi4bgh grams of pure copper sulfate in one liter4 ,the alkali solution is prepared by dissolving #cdf grams of rochelle salt and #bej grams of sodium hydroxid in water and completing the volume to one liter4 ,manipulation4--,twenty-five cubic centimeters of each solution are mixed with fifty of water and boiled4 ,to the boiling mixture twenty-five cubic centimeters of the levulose solution are added1 which must not contain more than one per cent of the sugar4 ,the boiling is then continued for fifteen minutes1 and the cuprous oxid collected1 washed and reduced to the metallic state in the usual way4 ,the quantity of levulose is then determined by inspection from the table given below4 ,other methods of determining levulose in mixtures will be given further on4 ,,table ,,for ,,the ,,estimation ,,of ,,levulose4 7,a7 ,milligrams of copper4 7,b7 ,milligrams of levulose4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #bj #g4ae #fb #ca4ff #ajd #ef4he #adf #hb4ha #ba #g4gh #fc #cb4be #aje #eg4df #adg #hc4dc #bb #h4da #fd #cb4hd #ajf #eh4jg #adh #hd4jf #bc #i4jd #fe #cc4dc #ajg #eh4fh #adi #hd4fh #bd #i4fg #ff #cd4jb #ajh #ei4cj #aej #he4ca #be #aj4cj #fg #cd4fb #aji #ei4ia #aea #he4ic #bf #aj4ha #fh #ce4ba #aaj #fj4eb #aeb #hf4ee #bg #aa4cc #fi #ce4ha #aaa #fa4ac #aec #hg4af #bh #aa4hd #gj #cf4dj #aab #fa4gd #aed #hg4hh #bi #ab4cf #ga #cg4jj #aac #fb4cf #aee #hh4dj #cj #ab4hg #gb #cg4ei #aad #fb4ig #aef #hi4je #ca #ac4df #gc #ch4ai #aae #fc4eh #aeg #hi4fi #cb #ad4je #gd #ch4gh #aaf #fd4ba #aeh #ij4cd #cc #ad4fd #ge #ci4ch #aag #fd4hd #aei #ij4ih #cd #ae4bc #gf #ci4ih #aah #fe4df #afj #ia4fc #ce #ae4hb #gg #dj4eh #aai #ff4ji #afa #ib4bf #cf #af4dj #gh #da4ag #abj #ff4gb #afb #ib4ij #cg #af4ii #gi #da4gg #aba #fg4cb #afc #ic4ec #ch #ag4eg #hj #db4cg #abb #fg4ib #afd #id4ag #ci #ah4af #ha #db4ig #abc #fh4ec #afe #id4hj #dj #ah4gd #hb #dc4eg #abd #fi4ac #aff #ie4dd #da #ai4cb #hc #dd4af #abe #fi4gc #afg #if4jh #db #ai4ia #hd #dd4gf #abf #gj4ce #afh #if4gg #dc #bj4di #he #de4cf #abg #gj4if #afi #ig4cc #dd #ba4jh #hf #de4if #abh #ga4eh #agj #ig4ii #de #ba4ff #hg #df4eg #abi #gb4ai #aga #ih4fc #df #bb4be #hh #dg4ag #acj #gb4ha #agb #ii4bg #dg #bb4hc #hi #dg4gh #aca #gc4dc #agc #ii4ij #dh #bc4db #ij #dh4ch #acb #gd4je #agd #ajj4ed #di #bd4jj #ia #dh4ih #acc #gd4fg #age #aja4ah #ej #bd4ei #ib #di4eh #acd #ge4bi #agf #aja4hb #ea #be4ah #ic #ej4ah #ace #ge4ia #agg #ajb4df #eb #be4gf #id #ej4gh #acf #gf4ec #agh #ajc4aa #ec #bf4ce #ie #ea4ch #acg #gg4ae #agi #ajc4ge #ed #bf4ic #if #ea4ih #ach #gg4gg #ahj #ajd4ci #ee #bg4eb #ig #eb4eh #aci #gh4ci #aha #aje4jd #ef #bh4aa #ih #ec4ai #adj #gi4ja #ahb #aje4fh #eg #bh4gj #ii #ec4gi #ada #gi4fd #ahc #ajf4cc #eh #bi4cj #ajj #ed4ci #adb #hj4bh #ahd #ajf4ig #ei #bi4hi #aja #ee4jj #adc #hj4ia #ahe #ajg4fb #fj #cj4dh #ajb #ee4fb #add #ha4ee #ahf #ajh4bg #fa #ca4jg #ajc #ef4bc #ade #hb4ah #ahg #ajh4ib 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #ahh #aji4ef #bcb #ach4eg #bgf #afh4fh #cbj #aii4ig #ahi #aaj4ba #bcc #aci4be #bgg #afi4cg #cba #bjj4ga #aij #aaj4hf #bcd #aci4ah #bgh #agj4jf #cbb #bja4dd #aia #aaa4ej #bce #adj4ei #bgi #agj4ge #cbc #bjb4ah #aib #aab4ad #bcf #ada4bg #bhj #aga4dd #cbd #bjb4ia #aic #aab4gh #bcg #ada4id #bha #agb4ad #cbe #bjc4fe #aid #aac4db #bch #adb4fb #bhb #agb4he #cbf #bjd4ci #aie #aad4jf #bci #adc4bi #bhc #agc4ee #cbg #bje4ac #aif #aad4gb #bdj #adc4ig #bhd #agd4bf #cbh #bje4hh #aig #aae4ch #bda #add4fe #bhe #agd4if #cbi #bjf4fb #aih #aaf4jd #bdb #ade4cb #bhf #age4fg #ccj #bjg4cf #aii #aaf4gj #bdc #adf4jj #bhg #agf4ci #cca #bjh4aj #bjj #aag4cf #bdd #adf4fg #bhh #agg4aj #ccb #bjh4hc #bja #aah4jb #bde #adg4ce #bhi #agg4hb #ccc #bji4eg #bjb #aah4fh #bdf #adh4jc #bij #agh4ec #ccd #baj4cj #bjc #aai4cc #bdg #adh4ga #bia #agi4bd #cce #baa4jd #bjd #aai4ii #bdh #adi4dj #bib #agi4ie #ccf #baa4gh #bje #abj4fe #bdi #aej4jh #bic #ahj4fe #ccg #bab4eb #bjf #aba4cj #bej #aej4gf #bid #aha4fc #cch #bac4be #bjg #aba4if #bea #aea4dd #bie #ahb4jg #cci #bac4ii #bjh #abb4fa #beb #aeb4ab #bif #ahb4gh #cdj #bad4gc #bji #abc4bg #bec #aeb4ha #big #ahc4di #cda #bae4dh #baj #abc4ib #bed #aec4di #bih #ahd4ba #cdb #baf4bc #baa #abd4eh #bee #aed4ag #bii #ahd4ib #cdc #baf4ig #bab #abe4bd #bef #aed4ia #cjj #ahe4fc #cdd #bag4gb #bac #abe4ij #beg #aee4fe #cja #ahf4ce #cde #bah4dg #bad #abf4ef #beh #aef4dj #cjb #ahg4jf #cdf #bai4ba #bae #abg4bb #bei #aeg4ad #cjc #ahg4gh #cdg #bai4ig #baf #abg4he #bfj #aeg4hh #cjd #ahh4di #cdh #bbj4ga #bag #abh4dh #bfa #aeh4di #cje #ahi4ba #cdi #bba4df #bah #abi4aj #bfb #aei4ji #cjf #ahi4ic #cej #bbb4ba #bai #abi4gc #bfc #aei4gj #cjg #aij4fe #cea #bbb4if #bbj #acj4cf #bfd #afj4cj #cjh #aia4cg #ceb #bbc4gb #bba #aca4jg #bfe #afj4ia #cji #aib4ji #cec #bbd4dg #bbb #aca4gg #bff #afa4fc #caj #aib4ha #ced #bbe4bc #bbc #acb4dh #bfg #afb4ce #caa #aic4ec #cee #bbe4ih #bbd #acc4ah #bfh #afc4jg #cab #aid4be #cef #bbf4gd #bbe #acc4hi #bfi #afc4gi #cac #aid4ig #ceg #bbg4di #bbf #acd4ef #bgj #afd4ea #cad #aie4fi #ceh #bbh4be #bbg #ace4bc #bga #afe4ba #cae #aif4da #cei #bbi4jj #bbh #ace4hi #bgb #afe4ij #caf #aig4ab #cfj #bbi4gf #bbi #acf4hi #bgc #aff4fj #cag #aig4hc #cfa #bcj4eb #bcj #acg4bc #bgd #afg4bi #cah #aih4ee #cfb #bca4bh #bca #acg4ij #bge #afg4ii #cai #aii4bf #cfc #bcb4je 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 #cfd #bcb4ha #cgj #bcg4ci #cgf #bda4hg #chb #bdf4be #cfe #bcc4eg #cga #bch4af #cgg #bdb4ea #chc #bdg4ag #cff #bcd4cc #cgb #bch4ic #cgh #bdc4ae #chd #bdh4jh #cfg #bce4aj #cgc #bci4fi #cgi #bdc4gi #che #bdh4ii #cfh #bce4hf #cgd #bdj4df #chj #bdd4dc #cfi #bcf4fc #cge #bda4bc #cha #bde4cd #adg4 ,precipitation of ,sugars with ,phenylhydrazin4--,the combination of phenylhydrazin with aldehyds and ketones was first studied by ,fischer1 and the near relationship of these bodies to sugar soon led to the investigation of the compounds formed thereby with this reagent4#aab ,reducing sugars form with phenylhydrazin insoluble crystalline bodies1 to which the name osazones has been given4 ,the reaction which takes place is a double one and is represented by the following formulas3 ,dextrose4 ,phenylhydrazin4 ,dextrose-phenylhydrazone4 ,c,h,o ,c,h,,nh4,,nh ,c,h,o4,n4,,nhc,h ,h,o and ,c,h,o4,n4,,nhc,h ,c,h,,nh4,,nh ,phenyldextrosazone4 ,c,h,o7,n4,,nhc,h7 #b;,h,o4 ,the dextrosazone is commonly called glucosazone4 ,the osazones formed with the commonly occurring reducing sugars are crystalline1 stable1 insoluble bodies which can be easily separated from any attending impurities and identified by their melting points4 ,glucosazone melts at #bje1 lactosazone at #bjj and maltosazone at #bjf4 ,the osazones are precipitated in the following way3 ,the reducing sugar1 in about ten per cent solution1 is treated with an excess of the acetate of phenylhydrazin in acetic acid and warmed to from #ge to #he4 ,in a short time the separation is complete and the yellow precipitate formed is washed1 dried and weighed4 ,the sugar can be recovered from the osazone by decomposing it with strong hydrochloric acid by means of which the phenylhydrazin is displaced and a body1 osone1 is formed1 which by treatment with zinc dust and acetic acid1 is reduced to the original sugar4 ,the reactions which take place are represented by the following equations3#aac ,glucososone4 ,c,h,o7,n4,,nh4,c,h7 #b;,h,o ,c,h,o #b;,c,h,n,h ,dextrose 7,glucose74 ,c,h,o ,h ,c,h,o4 ,for the complete precipitation of dextrose as osazone ,lintner and ,krber show that the solution of dextrose should not contain more than one gram in #ajj cubic centimeters4 ,twenty cubic centimeters containing #j4b gram dextrose should be used for the precipitation4#aad ,to this solution should be added one gram of phenylhydrazin and one gram of fifty per cent acetic acid4 ,the solution is then to be warmed for about two hours and the precipitate washed with from sixty to eighty cubic centimeters of hot water and dried for three hours at #aje4 ,one part of the osazone is equivalent to one part of dextrose when maltose and dextrin are absent4 ,when these are present the proportion is one part of osazone to #a4jd of dextrose4 ,where levulose is precipitated instead of dextrose #a4dc parts of the osazone are equal to one part of the sugar4 ,sucrose is scarcely at all precipitated as osazone until inverted4 ,after inversion and precipitation as above1 #a4cc parts osazone are equal to one part of sucrose4 ,the reaction with phenylhydrazin has not been much used for quantitive estimations of sugars1 but it has been found especially useful in identifying and separating reducing sugars4 ,it is altogether probable1 however1 that in the near future phenylhydrazin will become a common reagent for sugar work4 ,maquenne has studied the action of phenylhydrazin on sugars and considers that this reaction offers the only known means of precipitating these bodies from solutions where they are found mixed with other substances4#aae ,the osazones1 which are thus obtained1 are usually very slightly soluble in the ordinary reagents1 for which reason it is easy to obtain them pure when there is at the disposition of the analyst a sufficient quantity of the material4 ,but if the sugar to be studied is rare and if it contain1 moreover1 several distinct reducing bodies1 the task is more delicate4 ,it is easy then to confound several osazones which have almost identical points of fusion2 for example1 glucosazone with galactosazone4 ,finally1 it becomes impossible by the employment of phenylhydrazin to distinguish glucose1 dextrose or mannose from levulose alone or mixed with its isomers4 ,indeed1 these three sugars give1 with the acetate of phenylhydrazin the same phenylglucosazone which melts at about #bje4 ,it is noticed that the weights of osazones which are precipitated when different sugars are heated for the same time with the same quantity of the phenylhydrazin1 vary within extremely wide limits4 ,it is constant for each kind of sugar if the conditions under which the precipitation is made are rigorously the same4 ,there is then1 in the weight of the osazones produced1 a new characteristic of particular value4 ,the following numbers have been obtained by heating for one hour at #ajj1 one gram of sugar with #ajj cubic centimeters of water and five cubic centimeters of a solution containing forty grams of phenylhydrazin and forty grams of acetic acid per hundred4 ,after cooling the liquid1 the osazones are received upon a weighed filter1 washed with #ajj cubic centimeters of water1 dried at #aaj and weighed4 ,the weights of osazones obtained are given in the following table3 ,weight of the osazones4 ,character of the sugar4 gram4 ,sorbine1 crystallized #j4hb ,levulose 0 #j4gj ,xylose 0 #j4dj ,glucose1 anhydrous #j4cb ,arabinose1 crystallized #j4bg ,galactose 0 #j4bc ,rhamnose 0 #j4ae ,lactose 0 #j4aa ,maltose 0 #j4aa ,with solutions twice as dilute as those above1 the relative conditions are still more sensible1 and the different sugars arrange themselves in the same order1 with the exception of levulose1 which shows a slight advantage over sorbine and acquires the first rank4 ,from the above determinations1 it is shown that levulose and sorbine give vastly greater quantities of osazones1 under given conditions1 than the other reducing sugars4 ,it would be easy1 therefore1 to distinguish them by this reaction and to recognize their presence also even in very complex mixtures1 where the polarimetric examination alone would furnish only uncertain indications4 ,it is remarkable that these two sugars are the only ones among the isomers or the homologues of dextrose1 actually known1 which possess the functions of an acetone4 ,they are not1 however1 easily confounded1 since the glucosazone forms beautiful needles which are ordinarily visible to the naked eye1 while the sorbinosazone is still oily and when heated never gives perfectly distinct crystals4 ,this method also enables us to distinguish between dextrose and galactose1 of which the osazone is well crystallized and melts at almost the same temperature as the phenylglucosazone4 ,finally1 it is observed that the reducing sugars give less of osazones than the sugars which are not capable of hydrolysis1 and consequently differ in their inversion products4 ,it is specially noticed in this study of the polyglucoses 7bioses1 trioses71 that this new method of employing the phenylhydrazin appears very advantageous4 ,it is sufficient to compare the weights of the osazones to that which is given under the same conditions by a known glucose1 in order to have a very certain verification of the probabilities of the result of the chemical or optical examination of the mixture which is under study4 ,all the polyglucoses which have been examined from this point of view give very decided results4 ,the numbers which follow have reference to one gram of sugar completely inverted by dilute sulfuric acid1 dissolved in #ajj cubic centimeters of water1 and treated with two grams of phenylhydrazin1 the same quantity of acetic acid1 and five grams of crystallized sodium acetate4 ,all these solutions have been compared with the artificial mixtures and corresponding glucoses1 with the same quantities of the same reagents4 ,the following are the results of the examination3 ,weight of the osazone4 ,character of the sugar4 gram4 #a ,saccharose1 ordinary #j4ga ,glucose and levulose 74#ebf g each7 #j4gc #b ,maltose #j4ee ,glucose 7#a4jeb g7 #j4eh #c ,raffinose1 crystallized #j4dh ,levulose1 glucose and galactose 74#ccc g each7 #j4ec #d ,lactose1 crystallized #j4ch ,glucose and galactose 74#ejj g each7 #j4ci ,it is noticed that the agreement for each saccharose is as satisfactory as possible4 ,numbers obtained with the products of inversion are always a little low by reason of the destructive action of sulfuric acid1 and in particular1 upon levulose4 ,this is1 moreover1 quite sensible when the product has to be heated for a long time with sulfuric acid in order to secure a complete inversion4 ,it is evident from the data cited from the papers of ,fischer1 ,maquenne1 and others1 that the determination of sugars by this method is not a very difficult analytical process and may1 in the near future1 become of great practical importance4 #adh4 ,molecular ,weights of ,carbohydrates4--,in the examination of carbohydrates the determination of the molecular weights is often of the highest analytical value4 ,the uncertainty in respect of the true molecular weights of the carbohydrates is gradually disappearing by reason of the insight into the composition of these bodies1 which recently discovered physical relations have permitted4 ,raoult1 many years ago1#aaf proposed a method of determining molecular weights which is particularly applicable to carbohydrates soluble in water4 ,the principle of ,raoult's discovery may be stated as follows3 ,the depression of the freezing point of a liquid1 caused by the presence of a dissolved liquid or solid1 is proportionate to the absolute amount of substance dissolved and inversely proportionate to its molecular weight4 ,the following formulas may be used in computing results3 ,c observed depression of freezing point3 ,p weight of anhydrous substance in #ajj grams3 ,c --- ,a depression produced by one gram substance in #ajj grams3 ,p ,k depression produced by dissolving in #ajj cubic centimeters a number of grams of the substance corresponding to its molecular weight3 ,m molecular weight3 ,c ,then we have1 ,k ---- ,m4 ,p ,k is a quantity varying with the nature of the solvent but with the same solvent remaining sensibly constant for numerous groups of compounds4 ,the value of ,c ,a ---- ,p can be determined by experiment4 ,the molecular weight can therefore be calculated from the formula ,k ,m ----4 ,a ,with organic compounds in water the value of ,k is almost constant4 ,brown and ,morris#aag report results of their work in extending ,raoult's investigations of the molecular weight of the carbohydrates4 ,the process is carried on as follows3 ,a solution of the carbohydrate is prepared containing a known weight of the substance in #ajj cubic centimeters of water4 ,about #abj cubic centimeters of the solution are introduced into a thin beaker of about #djj capacity4 ,this beaker is closed with a stopper with three holes4 ,through one of these a glass rod for stirring the solution is inserted4 ,the second perforation carries a delicate thermometer graduated to #j4je4 ,the temperature is read with a telescope4 ,the beaker is placed in a mixture of ice and brine at a temperature from #b to #c below the freezing point of the solution4 ,the solution is cooled until its temperature is from #j4e to #a below the point of congelation4 ,through the third aperture in the stopper a small lump of ice taken from a frozen portion of the same solution1 is dropped1 causing at once the freezing process to begin4 ,the liquid is briskly stirred and as the congelation goes on the temperature rises and finally becomes constant4 ,the reading is then taken4 ,the depression in the freezing point1 controlled by the strength of the solution1 should never be more than from #a to #b4 ,the molecular weights may also be determined by the boiling points of their solutions as indicated by the author1#aah ,beckmann1#aai ,hite1 ,orndorff and ,cameron4#abj ,the method applied to some of the more important carbohydrates gave the following results3 ,,dextrose4 ,calculated for ,c,h,o4 ,found4 ,m #ahj ,m #ahj4b ,,sucrose4 ,calculated for ,c,h,o4 ,found4 ,m #cdb ,m #ccg4e ,,invertose 7,,dextrose ,,and ,,levulose74 ,calculated for ,c,h,o4 ,found4 ,m #ahj ,m #agd4c ,,maltose4 ,calculated for ,c,h,o4 ,found4 ,m #cdb ,m #cbb ,,lactose4 ,calculated for ,c,h,o4 ,found4 ,m #cdb ,m #cde ,,arabinose4 ,calculated for ,c,h,o4 ,found4 ,m #aej ,m #aej4c ,,raffinose4 ,calculated for ,c,h,o4#e;,h,o4 ,found4 ,m #eid ,m #ebh #adi4 ,birotation4--,as is well known1 dextrose exhibits in fresh solutions the phenomenon of birotation4 ,the authors supposed that this phenomenon might have some relation to the size of the molecule4 ,they1 therefore1 determined the molecular volume of freshly dissolved dextrose by the method of ,raoult and found ,m #ahj4 ,the high rotatory power of recently dissolved dextrose is therefore not due to any variation in the size of its molecule4 ,the mathematical theory of birotation is given by ,mller as follows4#aba ,in proportion as the unstable modification ,a is transformed into the stable modification ,b1 the rotation will vary4 ,let the specific rotatory power of ,b and a that of ,a1 both in the anhydrous state4 ,let now p grams of the substance be dissolved in ,v cubic centimeters of solvent and observed in a tube l decimeters in length4 ,the time from making the solution is represented by 4 ,the angle of rotation is read at the time 4 ,let x the mass of ,a1 and y that of ,b1 and the equation is derived4 axl yl --------- ------3 ,v ,v ,but x y p l whence 7a - #a7x p ----4 ,v ,if now there be introduced into the calculation the final angle of rotation 1 which can be determined with great exactness2 we have pl 7a - #a7x ------- and consequently #a ------------1 ,v p 7a - #a7x whence ------------- --- - #a4 p ,this equation gives the quantity x of the unstable matter which is transformed into the stable modification in the time 4 ,it must be admitted that the quantity dx which is changed during the infinitely small time d is proportional to the mass x which still exists at the moment 1 whence dx -,cxd where ,c represents a constant positive factor4 ,from this is derived the equation dx ----- -,cd4 x ,integrating and calling x the quantity of matter changed to the stable form at the moment 1 corresponding to a rotation 1 we have #a x ,c ------- log4 nap4 ----1 and taking into consideration - x the equation given above1 and substituting common for superior logarithms we get #a - ,c --------- log4 ---------4 - - ,experience has shown that such a constant ,c really exists1 and its value can be easily calculated from the data of ,parcus and ,tollens4#abb ,the mean value of ,c from these data is #j4jcja for arabinose2 #j4jbja for xylose2 #j4jcic for rhamnose2 #j4jbjb for fucose2 #j4jjibg for galactose2 #j4jjdje for lactose2 #j4jjebd for maltose1 and for dextrose1 #j4jjcdh at #aa to #ac and #j4jjcih from #ac to #ae4 ,the constant ,c as is well known1 increases as the temperature is raised4 ,the constant ,c1 at a given temperature1 measures the progress of the phenomenon of the change from the unstable to the stable state4 ,it will be noticed that among the sugars possessing multirotation properties the pentoses possess a much higher speed of transformation than the others4 #aej4 ,estimation of ,pentose ,sugars and ,pentosans as ,furfurol4--,the production of furfurol by distilling carbohydrates with an acid has already been mentioned4 ,tollens and his associates have shown that with pentose sugars1 and carbohydrate bodies yielding them1 the production of furfurol is quantitive4 ,the production and estimation of furfurol have been systematically studied by ,krug1 to whose paper the reader is referred for the complete literature of the subject4#abc ,the essential principles of the operation are based on the conversion of the pentoses into furfurol by distilling with a strong acid1 and the subsequent precipitation and estimation of the furfurol formed in the first part of the reaction4 ,the best method of conducting the distillation is as follows3 ,five grams of the pentose substance are placed in a flask of about a quarter liter capacity1 with #ajj cubic centimeters of hydrochloric acid of #a4jf specific gravity4 ,the arrangement of the apparatus is shown in ,fig4 #df4 ,the flame of the lamp is so regulated as to secure about two cubic centimeters of distillate per minute4 ,illustration3 ,,figure #df4 ,,distilling ,,apparatus ,,for ,,pentoses4 ,the distillate is received in a graduated cylinder and as soon as thirty cubic centimeters are collected1 an equal quantity of hydrochloric acid1 of the strength noted1 is added to the distilling flask1 allowing it to flow in slowly so as not to stop the ebullition4 ,the process is continued until a drop of the distillate gives no sensible reaction for furfurol when tested with anilin acetate4 ,the test is applied as follows3 ,place a drop of the distillate on a piece of filter paper moistened with anilin acetate4 ,the presence of furfurol will be disclosed by the production of a brilliant red color4 ,usually about three hours are consumed in the distillation1 during which time a little less than #djj cubic centimeters of distillate is obtained4 ,the distillate is neutralized with solid sodium carbonate and1 in order to have always the same quantity of common salt present1 #aj4b grams of sodium chlorid are added for each fifty cubic centimeters of water necessary to make the total volume to half a liter4#abd ,the reactions with pentosans probably consist in first splitting up of the molecule into a pentose and the subsequent conversion of the latter into furfurol according to the following equations3 7,c,h,o7 7,h,o7 7,c,h,o7 ,pentosan4 ,water4 ,pentose4 and 7,c,h,o7 7,c,h,o7 7#c;,h,o74 ,pentose4 ,furfurol4 ,water4 #aea4 ,determination of ,furfurol4--,the quantity of furfurol obtained by the process mentioned above may be determined in several ways4 ,as ,furfuramid4--,when ammonia is added to a saturated solution of furfurol1 furfuramid1 7,c,h,o7,n1 is formed4 ,in order to secure the precipitate it is necessary that the furfurol be highly concentrated and this can only be accomplished by a tedious fractional distillation4 ,this method1 therefore1 has little practical value4 ,as ,furfurolhydrazone4--,furfurol is precipitated almost quantitively1 even from dilute solutions1 by phenylhydrazin4 ,the reaction is represented by the equation3 ,c,h,n ,c,h,o ,c,h,n,o ,h,o4 ,phenylhydrazin4 ,furfurol4 ,furfurolhydrazone4 ,water4 #aeb4 ,volumetric ,methods4--,tollens and ,gnther have proposed a volumetric method which is carried out as follows3#abe ,the distillation is accomplished in the manner described4 ,the distillate is placed in a large beaker1 neutralized with sodium carbonate and acidified with a few drops of acetic4 ,phenylhydrazin solution of known strength is run in until a drop of the liquid1 after thorough mixing1 shows no reaction for furfurol with anilin acetate4 ,the reagent is prepared by dissolving five grams of pure phenylhydrazin and three of glacial acetic acid in distilled water1 and diluting to #ajj cubic centimeters4 ,the solution is set by dissolving from two-tenths to three-tenths gram of pure furfurol in half a liter of water and titrating with the phenylhydrazin as indicated above4 ,the quantity of the pentose used has a great influence on the result4 ,with nearly a gram of arabinose about fifty per cent of furfurol were obtained while when nearly five grams were used only about forty-six per cent of furfurol were found4 ,with xylose a similar variation was found1 the percentage of furfurol1 decreasing as the quantity of pentose increased4 ,the method1 therefore1 gives only approximately accurate results4 #aec4 ,method of ,stone4--,another volumetric method proposed by ,stone is based on the detection of an excess of phenylhydrazin by its reducing action on the fehling reagent4#abf ,a standard solution of phenylhydrazin is prepared by dissolving one gram of the hydrochlorate and three grams of sodium acetate in water and completing the volume of the liquor to #ajj cubic centimeters4 ,this solution contains #a4did milligrams of phenylhydrazin in each cubic centimeter1 theoretically equivalent to #a4cbh milligrams of furfurol4 ,the reagent is set by titrating against a known weight of furfurol4 ,pure furfurol may be prepared by treating the crude article with sulfuric acid and potassium dichromate1 and subjecting the product to fractional distillation4 ,the distillate is treated with ammonia and the furfuramid formed is purified by recrystallizing from alcohol and drying over sulfuric acid4 ,one gram of this furfuramid is dissolved in dilute acetic acid and the volume completed to one liter with water4#abg ,the phenylhydrazin solution being unstable1 is to be prepared at the time of use4 ,the titration is conducted as follows3 ,twenty-five cubic centimeters of the distillate obtained from a pentose body1 by the method described above1 are diluted with an equal volume of water1 a certain quantity of the phenylhydrazin solution added to the mixture from a burette and the whole heated quickly to boiling4 ,the flask is rapidly cooled and a portion of its contents poured on a filter4 ,the filtrate should have a pale yellow color and be perfectly clear4 ,if it become turbid on standing1 it should be refiltered4 ,two cubic centimeters of the clear filtrate are boiled with double the quantity of the fehling reagent4 ,if phenylhydrazin be present1 the color of the mixture will change from blue to green4 ,by repeating the work1 with varying quantities of phenylhydrazin1 a point will soon be reached showing the end of the reaction in a manner entirely analogous to that observed in volumetric sugar analysis4 ,in practice the volumetric methods have given place to the more exact gravimetric methods described below4 #aed4 ,gravimetric ,methods4--,the distillation is carried on and the volume of the distillate completed to half a liter as described above4 ,chalmot and ,tollens then proceed as follows3#abh ,ten cubic centimeters of a solution of phenylhydrazin acetate1 containing in #ajj cubic centimeters twelve grams of the phenylhydrazin and seven and a half grams of glacial acetic acid dissolved and filtered1 are added to the distillate and the mixture stirred with an appropriate mechanism for half an hour4 ,the furfurolhydrazone at the end of this time will have separated as small reddish-brown crystals4 ,the mixture is then thrown onto an asbestos filter and the liquid separated with suction4 ,the suction should be very gradually applied so as not to clog the felt4 ,the precipitate adhering to the beaker is washed into the filter with #ajj cubic centimeters of water4 ,the precipitate is dried at about #fj and weighed4 ,as a check the hydrazone may be dissolved in hot alcohol1 the filter well washed1 dried and again weighed4 ,to obtain the weight of furfurol the weight of hydrazone found is multiplied by #j4eaf and #j4jbe added to compensate for the amount which was held in solution or removed by washing4 ,less than one per cent of pentose can not be determined by this method since that amount is equalled by the known losses during the manipulation4 ,factor4--,to convert the furfurol found into pentoses1 the following factors are used3 ,per cent furfurol ,multiply for obtained from ,multiply for ,multiply for penta-glucoses five grams of arabinose by4 xylose by4 by4 pentoses4 #b4e per cent or less #a4ij #a4gj #a4fg #e4j 0 0 0 more #b4jd #a4ij #a4ib #aee4 ,method ,of ,krug4--,in conducting the determination of furfurol1 according to the method of ,chalmont and ,tollens just noticed1 ,krug observed that the filtrate1 after standing for some time1 yielded a second precipitate of furfurol hydrazone4 ,great difficulty was also experienced in collecting the precipitate upon the filter on account of the persistency with which it stuck to the sides of the vessel in which the precipitation took place4#abi ,in order to avoid these two objections1 ,krug modified the method as described below and this modified method is now exclusively used in this laboratory4 ,after the precipitation of the furfurol hydrazone1 it is stirred vigorously1 by means of an appropriate mechanical stirrer1 for at least half an hour and then allowed to rest for twenty-four hours4 ,on filtering after that length of time the filtrate remains perfectly clear and no further precipitation takes place4 ,after the filtration is complete and the beaker and filtering tube well washed1 no attempt is made to detach the part of the filtrate adhering to the beaker but the whole of the precipitate1 both that upon the filter and that adhering to the sides of the beaker1 is dissolved in strong alcohol1 from thirty to forty cubic centimeters being used4 ,the alcoholic solution is collected in a small weighed flask1 the alcohol evaporated at a gentle heat and the last traces of water removed by heating to #fj and blowing a current of dry air through the flask4 ,after weighing the precipitate of furfurol hydrazone1 obtained as above1 the calculation of the weight of pentose bodies is accomplished by means of the usual factors4 #aef4 ,precipitation of ,furfurol with ,pyrogalol4--,furfurol is thrown out of solution in combination with certain phenol bodies by heating together in an acid solution4 ,hotter has proposed a method for the determination of furfurol based on the above fact4#acj ,the furfurol is obtained by distillation in the manner already described and hydrochloric acid is added if necessary to secure twelve per cent of that body in a given volume4 ,the furfurol is thrown out of an aliquot portion by heating with an excess of pyrogalol in closed tubes for about two hours at #aaj4 ,the reaction takes place in two stages1 represented by the following equations3 ,c,h,o ,c,h,o ,c,h,o and #b;,c,h,o ,c,h,o ,h,o4 ,the aliquot part of the distillate used should not contain more than one-tenth of a gram of furfurol4 ,the precipitate formed in this way is collected on an asbestos felt1 dried at #ajc and weighed4 ,the weight obtained divided by #a4igd gives the corresponding amount of furfurol4 ,there is some difficulty experienced in loosening the precipitate from the sides of the tubes in which the heating takes place1 but this defect can be overcome by heating in covered beakers in an autoclave4 #aeg4 ,precipitation with ,phloroglucin4--,instead of using pyrogalol for the precipitating reagent phloroglucin may be employed4 ,the method of procedure proposed by ,councler for this purpose is given below4#aca ,the furfurol is prepared by distillation in the usual way4 ,the volume of the distillate obtained is completed to half a liter with twelve per cent hydrochloric acid1 and an aliquot portion1 varying in volume with the percentage of furfurol is withdrawn for precipitation4 ,this portion is placed in a glass-stoppered flask with about twice the quantity of finely powdered phloroglucin necessary to combine with the furfurol present4 ,the contents of the flask are well shaken and allowed to stand fifteen hours4 ,the precipitate is collected on an asbestos filter1 washed free of chlorin1 dried at the temperature of boiling water and weighed4 ,the theoretical quantity of precipitate corresponding to one part of furfurol1 viz41 #b4bb parts1 is never obtained since the precipitate is not wholly insoluble in water4 ,the actual proportions between the precipitate and the original furfurol vary with the amount of precipitate obtained4 ,when the weight of the precipitate is #bjj milligrams and over1 #b4ab parts correspond to one part of furfurol4 ,when the weight of the precipitate varies from fifty to #ajj milligrams1 the ratio is as #b4je3a and when only about twenty-five milligrams of precipitate are obtained the ratio is as #a4ih3a4 ,the quantity of pentose bodies corresponding to the furfurol is calculated from the factors given by ,tollens in a preceding paragraph4 ,the reaction which takes place with furfurol and phloroglucin is simply a condensation of the reagents with the separation of water4 ,it is very nearly represented by the following formula3 #b;,c,h,o ,c,h,o ,c,h,o ,h,o4 ,furfurol4 ,phloroglucin ,condensation ,water4 product4 ,it has been shown by ,welbel and ,zeisel1#acb that in the presence of twelve per cent of hydrochloric acid phloroglucin itself is condensed into dark insoluble compounds4 ,when three molecules of furfurol and two molecules of phloroglucin are present1 the bodies are both condensed and separated by continued action4 ,when from one and a quarter to three parts of phloroglucin by weight are used to one part of furfurol1 the weight of the precipitate obtained under constant conditions may serve sufficiently well for the calculation of the furfurol4 ,the precipitates contain chlorin1 which they give up even in the cold1 to water4 ,for these reasons the analytical data obtained by the method of ,councler1 given above1 are apt to be misleading4 ,it is probable also that similar conditions may to a certain extent prevail in the separation of furfurol with phenylhydrazin1 and further investigation in this direction is desirable4 ,for the present the very best method that can be recommended for the estimation of pentoses and pentosans is the conversion thereof into furfurol and the separation of the compound with phenylhydrazin acetate4 #aeh4 ,estimation of ,sugars by ,fermentation4--,when a solution of a hexose sugar is subjected to the action of certain ferments a decomposition of the molecule takes place with the production of carbon dioxid and various alcohols and organic acids4 ,under the action of the ferment of yeast ,saccharomyces cerevisiae the sugar yields theoretically only carbon dioxid and ethyl alcohol1 as represented by the equation3 ,c,h,o #b;,c,h,o #b;,,co4 ,the theoretical quantities of alcohol and carbon dioxid obtained according to this equation are #ea4aa percent of alcohol and #dh4hi per cent of carbon dioxid4 ,when the yeast ferment acts on cane sugar the latter first suffers inversion1 and the molecules of dextrose and levulose produced are subsequently converted into alcohol and carbon dioxid as represented below3 ,c,h,o ,h,o #b;,c,h,o #b;,c,h,o #d;,c,h,o #d;,,co4 ,cane sugar1 plus the water of hydrolysis1 will yield theoretically #ec4h per cent of alcohol and #ea4e per cent of carbon dioxid4 ,in practice the theoretical proportions of alcohol and carbon dioxid are not obtained because of the difficulty of excluding other fermentative action1 resulting in the formation especially of succinic acid and glycerol4 ,moreover1 a part of the sugar is consumed by the yeast cells to secure their proper growth and development4 ,in all only about ninety-five per cent of the sugar can be safely assumed as entering into the production of alcohol4 ,about #dh4e per cent of alcohol are all that may be expected of the weight of dextrose or invert sugar used4 ,only sugars containing three molecules of carbon or some multiple thereof are fermentable4 ,thus the trioses1 hexoses1 nonoses1 etc41 are susceptible of fermentation1 while the tetroses1 pentoses1 etc41 are not4 #aei4 ,estimating ,alcohol4--,in the determination of sugar by fermentation1 a rather dilute solution not exceeding ten per cent should be used4 ,a quantity of pure yeast1 equivalent to four or five per cent of the sugar used1 is added1 and the contents of the vessel1 after being well shaken1 exposed to a temperature of from #be to #cj until the fermentation has ceased1 which will be usually in from twenty-four to thirty-six hours4 ,the alcohol is then determined in the residue by the methods given hereafter4 ,the weight of the alcohol obtained multiplied by #ajj and divided by #dh4e1 will give the weight of the hexose reducing sugar which has been fermented4 ,ninety-five parts of sucrose will give #ajj parts of invert sugar4 ,example4--,let the weight of alcohol obtained be #j4fbe gram4 ,then #j4fbe #ajj #dh4e #a4bhi grams1 the weight of the hexose1 which has been fermented2 #a4bhi grams of dextrose or levulose correspond to #a4bbe of sucrose4 #afj4 ,estimating ,carbon ,dioxid4--,the sugar may also be determined by estimating the amount of carbon dioxid produced during the fermentation4 ,for this purpose the mixture of sugar solution and yeast1 prepared as above mentioned1 is placed in a flask whose stopper carries two tubes1 one of which introduces air free of carbon dioxid into the contents of the flask1 and the other conducts the evolved carbon dioxid into the absorption bulbs4 ,in passing to the absorption bulbs the carbon dioxid is freed of moisture by passing through another set of bulbs filled with strong sulfuric acid4 ,during the fermentation1 the carbon dioxid is forced through the bulbs by the pressure produced1 or better1 a slow current of air is aspirated through the whole apparatus4 ,the aspiration is continued after the fermentation1 has ceased1 until all the carbon dioxid is expelled4 ,towards the end1 the contents of the flask may be heated to near the boiling-point4 ,the increase of the weight of the potash bulbs will give the weight of carbon dioxid obtained4 ,a hexose reducing sugar will yield about #df4e per cent of its weight of carbon dioxid4 ,the calculation is made as suggested for the alcohol process4 ,the fermentation process has little practical value save in determining sucrose in presence of lactose1 as will be described in another place4 #afa4 ,precipitation of ,sugars in ,combination with the ,earthy ,bases4--,the sugars combine in varying proportions with the oxids and hydroxids of calcium1 strontium and barium4 ,sucrose especially1 furnishes definite crystalline aggregates with these bases in such a way as to form the groundwork of several technical processes in the separation of that substance from its normally and abnormally associated compounds4 ,these processes have little use as analytical methods1 but are of great value1 as mentioned1 from a technical point of view4 #afb4 ,barium ,saccharate4--,this compound is formed by mixing the aqueous solutions of barium hydroxid and sugar4 ,the saccharate separates in bright crystalline plates or needles from the warm solution1 as ,c,h,o,ba,o4 ,one part of this precipitate is soluble in about forty-five parts of water1 both at #ae and #ajj4 #afc4 ,strontium ,saccharates4--,both the mono- and distrontium saccharates are known1 viz41 ,c,h,o,sr,o #e;,h,o and ,c,h,o#b,sr,o4 ,the monosalt may be easily secured by adding a few of its crystals to a mixture of sugar and strontium hydroxid solutions4 ,the disaccharate is precipitated as a granular substance when from two to three molecules of strontium hydroxid are added to a boiling sugar solution4 ,the reaction is extensively used in separating the sugar from beet molasses4 #afd4 ,calcium ,saccharates4--,three calcium saccharates are known in which one molecule of sugar is combined with one1 two and three molecules of lime respectively4 ,the monosaccharate is obtained by mixing the sugar and lime in the proper proportion and precipitating by adding alcohol4 ,the precipitate is partly granular and partly jelly-like1 and is soluble in cold water4 ,the dicalcium compound is obtained in the same way and has similar properties4 ,both1 on boiling1 with water1 form the trisaccharate and free sugar4 ,the tricalcium saccharate is the most important of these compounds1 and may be obtained directly by mixing freshly burned and finely ground lime 7,ca,o7 with a very cold dilute solution of sugar4 ,the compound crystallizes with three or four molecules of water4 ,when precipitated as described above1 however1 it has a granular1 nearly amorphous structure1 and the process is frequently used in the separation of sugar from beet molasses4 ,in the laboratory but little success has been had in using even the barium hydroxid as a chemical reagent1 and therefore the reactions mentioned above are of little value for analytical purposes4 ,in separating sugar from vegetable fibers and seeds1 however1 the treatment with strontium hydroxid is especially valuable the sugar being subsequently recovered in a free state by breaking up the saccharate with carbon dioxid4 ,the technical use of these reactions also is of great importance in the beet sugar industry4 #afe4 ,qualitive ,tests for the ,different ,sugars4--,the analyst will often be aided in examining an unknown substance by the application of qualitive tests1 which will disclose to him the nature of the saccharine bodies with which he has to deal4 #aff4 ,optical ,test for ,sucrose4--,the simplest test for the presence of sucrose is made with the polariscope4 ,a small quantity of the sample under examination is dissolved in water1 clarified by any of the usual methods1 best with alumina cream1 and polarized4 ,a portion of the liquor is diluted with one-tenth its volume of strong hydrochloric acid and heated to just #fh1 consuming about fifteen minutes time in the operation4 ,the mixture is quickly cooled and again polarized in a tube one-tenth longer than before used2 or the same tube may be used and the observed reading of the scale increased by one-tenth4 ,if sucrose be present the second reading will be much lower than the first1 or may even be to the left4 #afg4 ,cobaltous ,nitrate ,test for ,sucrose4--,sucrose in solution may be distinguished from other sugars by the amethyst violet color which it imparts to a solution of cobaltous nitrate4 ,this reaction was first described by ,reich1 in #ahef1 but has only lately been worked out in detail4 ,the test is applied as follows3 ,to about fifteen cubic centimeters of the sugar solution add five cubic centimeters of a five per cent solution of cobaltous nitrate4 ,after thoroughly mixing the two solutions1 add two cubic centimeters of a fifty per cent solution of sodium hydroxid4 ,pure sucrose gives by this treatment an amethyst violet color1 which is permanent4 ,pure dextrose gives a turquoise blue color which soon passes into a light green4 ,when the two sugars are mixed the coloration produced by the sucrose is the predominant one1 and one part of sucrose in nine parts of dextrose can be distinguished4 ,if the sucrose be mixed with impurities such as gum arabic or dextrin1 they should be precipitated by alcohol or basic lead acetate1 before the application of the test4 ,dextrin may be thrown out by treatment of the solution with barium hydroxid and ammoniacal lead acetate4 ,the reaction may also be applied to the detection of cane sugar in wines1 after they are thoroughly decolorized by means of lead acetate and bone-black4 ,the presence of added sucrose to milk1 either in the fresh or condensed state1 may also be detected after the disturbing matters are thrown out with lead acetate4 ,the presence of sucrose in honey may also be detected by this process4 ,the reaction has been tried in this laboratory with very satisfactory results4 ,the amethyst violet coloration with sucrose is practically permanent4 ,on boiling the color is made slightly bluish1 but is restored to the original tint on cooling4 ,dextrose gives at first a fine blue color which in the course of two hours passes into a pale green4 ,a slight flocculent precipitate is noticed in the tube containing the dextrose4 ,maltose and lactose act very much as dextrose1 but in the end do not give so fine a green color4 ,if the solutions containing dextrose1 lactose and maltose be boiled1 the original color is destroyed and a yellow-green color takes its place4 ,the reaction is one which promises to be of considerable practical value to analysts1 as it may be applied for the qualitive detection of sucrose in seeds and other vegetable products4#acc #afh4 ,the ,dextrose ,group4--,in case the carbohydrate in question shows a right-handed rotation and the absence of sucrose is established by the polariscopic observation described above1 the presence of the dextrose group may be determined by the following test4#acd ,five grams of the carbohydrate are oxidized by boiling with from twenty to thirty cubic centimeters of nitric acid of #a4ae specific gravity1 and then at gentle heat evaporated to dryness with stirring4 ,if much mucic acid be present1 as will be the case if the original matter contained lactose some water is added and the mixture well stirred1 and again evaporated to dryness to expel all nitric acid4 ,the residue should be of a brown color4 ,the mass is again mixed with a little water and the acid reaction neutralized by rubbing with fine-ground potassium carbonate4 ,the carbonate should be added in slight excess and acetic acid added to the alkaline mixture1 which is concentrated by evaporation and allowed to stand a few days4 ,at the end of this time potassium saccharate has formed and is separated from the mother liquid by pouring on a porous porcelain plate4 ,the residue is collected1 dissolved in a little water and again allowed to crystallize1 when it is collected on a porous plate1 as before1 and washed by means of an atomizer with a little aqueous spray until it is pure white and free of any oxalic acid4 ,the residual acid potassium saccharate may be weighed after drying and then converted into the silver salt4 ,the potash salt for this purpose is dissolved in water1 neutralized with ammonia and precipitated with a solution of silver nitrate4 ,the precipitate is well stirred1 collected on a gooch and washed and dried in a dark place4 ,it contains #ej4id percent of silver4 ,all sugars which contain the dextrose group yield silver saccharate when treated as above described4 ,inulin1 sorbose1 arabinose and galactose yield no saccharic acid under this treatment1 and thus it is shown that they contain no dextrose group4 ,milk sugar1 maltose1 the dextrins1 raffinose and sucrose yield saccharic acid when treated as above and therefore all contain the dextrose group4 #afi4 ,levulose4--,the levulose group of sugars1 wherever it occurs1 when oxidized with nitric acid1 gives rise to tartaric1 racemic1 glycolic and oxalic acids1 which are not characteristic1 being produced also by the oxidation of other carbohydrates4 ,a more distinguishing test is afforded by the color reactions produced with resorcin4#ace ,the reagent is prepared by dissolving half a gram of resorcin in thirty cubic centimeters each of water and strong hydrochloric acid4 ,to the sugar solution under examination an equal volume of strong hydrochloric acid is added1 and then a few drops of the reagent4 ,the mixture is gently warmed1 and in the presence of levulose develops a fire-red color4 ,dextrose1 lactose1 mannose and the pentoses do not give the coloration1 but it is produced by sorbose in a striking degree1 and also by sucrose and raffinose since these sugars contain the levulose group4 #agj4 ,galactose4--,the galactose which arises from the hydrolysis of milk sugar is readily recognized by the mucic acid which it gives on oxidation with nitric acid4#acf ,the analytical work is conducted as follows3 ,the body containing galactose or galactan is placed in a beaker with about sixty cubic centimeters of nitric acid of #a4ae specific gravity for each five grams of the sample used4 ,the beaker is placed on a steam-bath and heated1 with frequent stirring1 until two-thirds of the nitric acid have been evaporated4 ,the residual mixture is allowed to stand over night and the following morning is treated with ten cubic centimeters of water1 allowed to stand for twenty-four hours1 filtered through a gooch1 and the collected matter washed with twenty-five cubic centimeters of water1 dried at #ajj and weighed4 ,the mucic acid collected in this way will amount to about thirty-seven per cent of the milk sugar or seventy-five per cent of the galactose oxidized4 ,raffinose yields under similar treatment1 about twenty-three per cent of mucic acid1 which proves that the galactose group is contained in that sugar4 ,raffinose1 therefore1 is composed of one molecule each of dextrose1 levulose1 and galactose4 #aga4 ,invert ,sugar4--,the presence of a trace of invert sugar accompanying sucrose can be determined by ,soldaini's solution1 paragraph #abd1 or by boiling with methyl blue4#acg ,methyl blue is the hydrochlorate of an ammonium base1 which1 under the influence of a reducing agent1 loses two atoms of hydrogen and becomes a colorless compound4 ,the test for invert sugar is made as follows3 ,the reagent is prepared by dissolving one gram of methyl blue in water4 ,if the sugar solution is not clear1 twenty grams of the sugar are dissolved in water clarified by lead subacetate1 the volume completed to #ajj cubic centimeters1 and the solid matters separated by filtration4 ,the filtrate is made slightly alkaline with sodium carbonate to remove the lead4 ,a few drops of soda lye solution are then added and the mixture thrown on a filter4 ,to twenty-five cubic centimeters of the filtrate a drop of the methyl blue solution is added1 and a portion of the liquor heated in a test tube over the naked flame4 ,if1 after boiling for one minute1 the coloration disappear1 the sample contains at least #j4ja per cent of invert sugar2 if the solution remain blue it contains none at all or less than #j4ja per cent4 ,the test may also be made with the dilute copper carbonate solution of ,ost described further on4 #agb4 ,compounds with ,phenylhydrazin4--,many sugars may also be qualitively distinguished by the character of their compounds with phenylhydrazin4 ,in general1 it may be said that those sugars which reduce fehling solution form definite crystalline compounds with the reagent named4 ,if a moderately dilute hot solution of a reducing sugar be brought into contact with phenylhydrazin acetate1 a crystalline osazone is separated4 ,the reaction takes place between one molecule of the sugar and two molecules of the hydrazin compound1 according to the following formula3 ,c,h,o #b;,c,h,n,h ,c,h,n,o #b;,h,o ,h4 ,the hydrogen does not escape but combines in the nascent state with the excess of phenylhydrazin to form anilin and ammonia4 ,the precipitation is accomplished as follows3 ,one part by weight of the sugar1 two parts of phenylhydrazin hydrochlorate1 and three parts of sodium acetate are dissolved in twenty parts of water and gradually heated on the water-bath4 ,the osazone slowly separates in a crystalline form and it is freed from the mother liquor by filtration1 and purified by solution in alcohol and recrystallization4 ,the crystals are composed of yellow needles1 which are difficultly soluble in water and more easily in hot alcohol4 ,the crystals are not decomposed by a dilute acid but are destroyed by the action of strong acids4 ,dextrosazone4--,the crystals melt at from #bjd to #bje1 reduce fehling liquor1 and dissolved in glacial acetic acid are slightly left rotating4 ,levulosazone4--,this body has the same properties as the dextrose compound4 ,maltosazone4--,this substance melts at #bjf with decomposition4 ,it is left rotating4 ,its structure is represented by the formula ,c,h,n,o4 ,galactosazone4--,this substance1 ,c,h,n,o1 has the same centesimal composition as the corresponding bodies produced from dextrose and levulose4 ,it is distinguished from these compounds1 however1 by its low melting point1 viz41 #aic4 ,the above comprise all the phenylosazones which are important from the present point of view4 ,sucrose1 by inversion1 furnishes a mixture of dextros- and levulosazones when treated with phenylhydrazin1 while starch and dextrin yield the dextros- or maltosazone when hydrolyzed4 ,lactose yields a mixture of dextros- and galactosazones when hydrolyzed and treated as above described4 ,the reactions with phenylhydrazin are approximately quantitive and it is possible that methods of exact determination may be based on them in the near future4#ach #agc4 ,other ,qualitive ,tests for ,sugars4--,the analyst may sometimes desire a more extended test of qualitive reactions than those given above4 ,the changes of color noticed on heating with alkalies may often be of advantage in discriminating between different sugars4 ,the formation of definite compounds with the earthy and other mineral bases may also be used for qualitive determinations4 ,one of the most delicate qualitive tests is found in the production of furfurol and this will be described in the following paragraphs4 #agd4 ,detection of ,sugars and ,other ,carbohydrates by ,means of ,furfurol4--,the production of furfurol 7furfuraldehyd7 as noted in paragraph #aej1 is also used quantitively for the determination of pentose sugars and pentosans4 ,furfurol was first obtained from bran 7furfur71 whence its name1 by treating this substance with sulfuric acid1 diluted with three volumes of water1 and subjecting the mixture to distillation4 ,its percentage composition is represented by the symbol ,c,h,o1 and its characteristics as an aldehyd by the molecular structure ,c,h,o1,c-,,ho4 ,carbohydrates in general1 when treated as described above for bran1 yield furfurol1 but only in a moderate quantity1 with the exception of the pentoses4 ,mylius has shown#aci that ,pettenkofer's reaction for choleic acid is due to the furfurol arising from the cane sugar employed1 which1 with the gall acid1 produces the beautiful red-blue colors characteristic of the reaction4 ,von ,udrnszky#adj describes methods for detecting traces of carbohydrates by the furfurol reaction1 which admit of extreme delicacy4 ,the solution of furfurol in water1 at first proposed by ,mylius1 is to be used and it should not contain more than two and two-tenths per cent1 while a solution containing five-tenths per cent furfurol is found to be most convenient4 ,the furfurol1 before using1 should be purified by distillation1 and1 as a rule1 only a single drop of the solution used for the color reaction4 ,the furfurol reaction proposed by ,schiff#ada appears to be well suited for the detection of carbohydrates4 ,it is made as follows3 ,xylidin is mixed with an equal volume of glacial acetic acid and the solution treated with some alcohol4 ,strips of filter paper are then dipped in the solution and dried4 ,when these strips of prepared paper are brought in contact with the most minute portion of furfurol1 furoxylidin is formed1 ,c,h,,och7,c,h,,nh71 producing a beautiful red color4 ,in practice1 a small portion of the substance1 supposed to contain a carbohydrate1 is placed in a test tube and heated with a slight excess of concentrated sulfuric acid4 ,the prepared paper is then placed over the mouth of the test tube so as to be brought into contact with the escaping vapors of furfurol4 ,the furfurol reaction with -naphthol for some purposes1 especially the detection of sugar in urine1 is more delicate than the one just described4 ,this reaction was first described by ,molisch#adb1 who1 however1 did not understand its real nature4 ,the process is carried on as follows3 ,the dilute solution should contain not to exceed from #j4je to one-tenth per cent of carbohydrates4 ,if stronger1 it should be diluted4 ,place one drop of the liquid in a test tube with two drops of fifteen per cent alcoholic solution of -naphthol1 add carefully one-half cubic centimeter of concentrated sulfuric acid1 allowing it to flow under the mixture4 ,the appearance of a violet ring over a greenish fringe indicates the presence of a carbohydrate4 ,if the substance under examination contain more than a trace of nitrogenous matter1 this must be removed before the tests above described are applied4 ,if the liquids be mixed by shaking when the violet ring is seen1 a carmine tint with a trace of blue is produced4 ,if this be examined with a spectroscope1 a small absorption band will be found between ,d and ,e1 and from ,f outward the whole spectrum will be observed4 ,one drop of dextrose solution containing #j4je per cent of sugar gives a distinct reaction by this process4 ,it can be used1 therefore1 to detect the presence of as little as #j4jbh milligram of grape sugar4 ,this test has been found exceedingly delicate in this laboratory1 and sufficiently satisfactory without the spectroscopic adjunct4 ,the furfurol reaction is useful in detecting the presence of minute traces of carbohydrates but is of little value in discriminating between the different classes of these bodies4 ,it is not practical here to go into greater detail in the description of qualitive reactions4 ,the analyst1 desiring further information1 should consult the standard works on sugar chemistry4#adc #age4 ,detection of ,sugars by ,bacterial ,action4--,many forms of bacteria manifest a selective action towards sugars and this property may in the future become the basis of a qualitive and even quantitive test for sugars and other carbohydrates4 ,our present knowledge of the subject is due almost exclusively to the researches of ,smith1 conducted at the ,department of ,agriculture4#add ,dextrose is the sugar first and most vigorously attacked by bacterial action1 and by proper precautions the whole of the dextrose may be removed from mixtures with sucrose and lactose4 ,the development of other forms of micro-organisms which will have the faculty of attacking other and special forms of carbohydrates is to be looked for with confident assurance of success4 ,,determination ,,of ,,starch4 #agf4 ,constitution of ,starch4--,the molecule of starch is without doubt formed by the condensation of a large number of hexose bodies4 ,on account of its great insolubility its molecular weight has not been determined with any degree of accuracy4 ,its formula may be expressed either as 7,c,h,o7 or 7,c,h,o74 ,it is insoluble in cold water and other common solvents and does not pass into solution in any reagent without undergoing a change of structure4 ,in hot water it forms a paste and when heated under pressure with water it undergoes a partial change and becomes soluble4 ,heated with acids or subjected to the action of certain ferments it suffers hydrolysis and is transformed into dextrin1 maltose and dextrose4 ,in analytical work an attempt is usually made to transform the starch entirely into dextrose1 the quantity of which is then determined by some of the processes already given4 ,all starches possess the property of giving an intensely blue color with iodin and this reaction serves to detect the most minute quantity of the material4 ,starch grains derived from different sources are distinguished by differences in size and appearance4 ,in most cases a careful examination of the starch particles will reveal their origin4#ade ,the greatest part of the cereal grains is composed of starch1 the percentage ranging from sixty to eighty4 ,rice has the greatest percentage of starch in its composition of any substance4 ,certain root crops are also rich in starch1 such as the potato1 artichoke and cassava4 ,starch appears as one of the first products of vegetable metabolism1 according to some authorities1 preceding the formation of sugars4 ,by reason of its greater complexity1 however1 it is more probable that the production of simple sugars precedes the formation of the more complex molecule4 ,starch granules are probably used as a food by the plant in the building of more complex structures and the excess of this food is stored in the seeds and in tubers4 #agg4 ,separation of ,starch ,particles4--,advantage is taken of the insolubility of the starch particles to secure their separation from the other vegetable structures with which they are associated4 ,the substances containing starch are reduced to a pulp as fine as possible1 and this pulp being placed in a fine cloth the starch particles are washed through the cloth with water4 ,the milky filtrate carrying the starch is collected in an appropriate holder and1 after some time1 the particles subside4 ,they may then be collected and dried4 ,while this process is the one used commercially in the manufacture of starch1 it can only give approximate data respecting the actual quantity of starch in a given weight of the sample4 ,it is not quite possible by this method to get all the starch separated from the rest of the vegetable matter1 and particles of foreign substances1 such as cellulose and albuminoid matters1 may pass through the filter cloth and be found with the deposited granules4 ,it follows from this that the quantitive determination of the starch in a given sample by any direct method is only approximately exact4 #agh4 ,methods of ,separation4--,hot acids cannot be safely employed to dissolve starch from its natural concomitants because other carbohydrate bodies become soluble under similar conditions4 ,in such cases the natural sugars which are present should be removed by cold water and the starch dissolved from the residue by a diastatic ferment4 ,instead of this the sugars may be determined in a separate portion of the pulped material and the starch1 together with the sugars1 determined1 and the quantity of sugar found deducted from the final result4 ,in these cases the final determinations are made on the sugars1 after inverting the sucrose1 and proceeding as directed for invert sugars in paragraph #ada4 ,the starch1 after separation with diastase1 is converted into dextrose by one of the methods to be given and the resulting dextrose determined by one of the approved methods4 #agi4 ,separation with ,diastase4--,diastase or malt extract at a temperature of about #fe rapidly renders starch soluble4 ,cereals1 potato meal and other starch-holding bodies are dried1 first at a low temperature1 and extracted with ether or petroleum to remove fat4 ,the material is then rubbed up with water1 boiled1 cooled to #fe1 and treated with malt extract 7diastase7 prepared as given below4 ,one kilogram of ground green malt is mixed with one liter of glycerol and an equal quantity of water1 and allowed to stand1 with frequent shaking1 for eight days4 ,after that time the mixture is filtered1 first through a small filter press and afterwards through paper4 ,in case no filter press is at hand the mixture may be pressed in a bag and the liquor obtained1 filtered4 ,malt extract obtained in this way will keep its diastatic properties for a long time4 ,in its use1 blank determinations must be made of the dextrose produced by treating equal portions of it with hydrochloric acid4 ,for three grams of starchy material twenty-five cubic centimeters of the malt solution should be used and the mixture kept at #fe for two hours4#adf #ahj4 ,method in ,use at the ,halle ,station4--,the method of separating starch from cereals1 potatoes and other starch-holding materials1 employed at the ,halle station1 is essentially the same as already described4#adg ,the malt extract used is prepared immediately beforehand1 inasmuch as no preservative is added to it4 ,it can be quickly prepared by digesting1 for a short time at not above #ej1 #ajj grams of finely ground dried malt with one liter of water and separating the extract by filtration4 ,this extract will keep only a few hours4 ,the material in which the starch is to be determined is dried and extracted with ether4 ,from two to four grams of the extracted material1 according to the amount of starch which it contains1 are boiled for half an hour with #ajj cubic centimeters of water1 cooled to #fe1 treated with ten cubic centimeters of malt extract and kept at the temperature named for half an hour4 ,it is then again boiled for fifteen minutes1 cooled to the temperature mentioned and again treated with malt extract as above4 ,two treatments with malt extract are usually sufficient to bring all the starch into solution4 ,finally it is again boiled and the volume completed to #bej cubic centimeters and thrown upon a filter4 ,two hundred cubic centimeters of the filtrate are converted into dextrose by boiling with hydrochloric acid1 and the rest of the analysis is conducted in the usual manner4 ,the dextrose value of the quantity of malt extract used must be determined upon a separate portion thereof1 and the quantity of dextrose found deducted from the total amount obtained in the analysis4 ,illustration3 ,,figure #dg4 ,,autoclave ,,for ,,starch ,,analysis4 #aha4 ,separation by ,hydrolysis with ,water at ,high ,temperatures4--,instead of dissolving the starch with diastase1 it may be brought into solution by heating with water under pressure4 ,the former method employed of heating in sealed flasks has been entirely superceded by heating in an autoclave4 ,the materials are best held in metal beakers furnished with a cover which prevents loss from boiling if the pressure should be removed too rapidly after the completion of the operation4 ,the autoclave is a strong metal vessel capable of resisting the pressure of several atmospheres4 ,it is furnished with a pressure gauge ,c and a safety valve ,d1 as shown in the figure4 ,the top is securely screwed on by means of a wrench1 shown at the right hand side4 ,in the figure a portion of the case is represented cut away to show the arrangement of the metal beakers inside4 ,in the method of ,reinke1 as practiced at the ,halle station1 and in this laboratory1 about three grams of the starchy substance are placed in each of the metal beakers with twenty-five cubic centimeters of a one per cent lactic acid solution and thirty cubic centimeters of water4 ,the contents of the beaker are thoroughly mixed and they are then heated for two and a half hours in the autoclave1 at a pressure of three and a half atmospheres4 ,the addition of the lactic acid is for the purpose of protecting any sugar which may be present from decomposition at the high pressure and temperature employed4 ,after the completion of the heating1 the autoclave is allowed to cool1 the cover is removed and the beakers taken out and their contents washed with hot water into quarter liter flasks4 ,after cooling1 the volume is completed with cold water1 and after standing for half an hour1 with frequent shaking1 the contents of the flasks are filtered and #bjj cubic centimeters of the filtrate in each case converted into dextrose with hydrochloric acid in the usual way4 ,in order to obtain agreeing results1 it is highly necessary that the substance before treatment should be ground to a fine powder4 ,the addition of the lactic acid1 as practiced in the reinke method1 tends to give somewhat high results1 due probably to the hydrolytic action of the acid on the fiber present4 ,when starchy bodies are heated in the autoclave for the determination of their starch by polarimetric methods1 or for ordinary determinations1 the use of lactic acid should be omitted4 ,example4--,the following data indicate the methods of calculation to be followed in the determination of the percentage of starch in the material by diastatic hydrolysis3 ,three grams of a barley were inverted by diastase1 as directed above1 the volume of the solution made a quarter of a liter1 filtered1 #bjj cubic centimeters of the filtrate converted into dextrose by hydrochloric acid1 the volume completed to half a liter with water and fifty cubic centimeters thereof oxidized by the alkaline copper solution in the usual way4 ,the amount of copper obtained was #cca milligrams1 corresponding to #agd milligrams of dextrose4 ,the amount of malt extract used in hydrolyzing the barley mentioned above1 was ten cubic centimeters4 ,the diastatic solution inverted with hydrochloric acid and treated as indicated above1 yielded #aia milligrams of copper1 corresponding to ninety-eight milligrams of dextrose in ten cubic centimeters of the malt extract4 ,the quantity of malt extract represented in the final determination of copper1 however1 was only one and six-tenths cubic centimeters4 ,we then have3 ,total dextrose #agd milligrams ,dextrose in one and six-tenths cubic centimeters malt extract #af milligrams ,dextrose corresponding to #bdj milligrams of barley #aeh milligrams ,calculated on the proportion that dextrose is to starch1 as ten is to nine1 this is equivalent to #adb milligrams of starch4 ,the percentage of starch in the original substance1 therefore1 was equivalent to #adb multiplied by #ajj1 divided by #bdj1 viz41 #ei4ag4 #ahb4 ,principles of the ,methods of ,determination4--,in the approximately pure state in which starch exists in the trade1 it may be determined by conversion into dextrose and estimating the latter by one of the methods given4 ,it is probable that there is no known method by which starch can be entirely converted into dextrose1 and all the methods of hydrolysis1 when used for quantitive purposes1 must be standardized1 not by the theoretical quantity of dextrose which a given weight of pure starch should yield1 but by the actual quantity obtained4 ,starch is not largely converted into dextrose by any of the diastatic ferments which produce principally maltose and dextrins4 ,recourse must therefore be had to strong acids4 ,in practice1 hydrochloric is the one usually employed4 ,by the action of a hot mineral acid1 not only is starch converted into dextrose1 but also the dextrose found is subjected to changes4 ,in such cases an opposing action seems to be exerted by the hydrolytic agent1 a part of the dextrose formed suffering a partial condensation1 and thus assuming a state of higher molecular weight1 approaching the constitution of the dextrins4 ,another part of the dextrose may also suffer oxidation and thus disappear entirely in respect of the further steps in starch analysis4 ,in such cases1 the best the analyst can do is to conduct the hydrolysis in as nearly as possible constant conditions1 and to assume that the percentage of dextrose present at a given time bears a constant ratio to the quantity of starch hydrolyzed4 ,in reality almost all the starch appears finally as dextrose1 and by proceeding on the assumption noted above a fairly satisfactory accounting may be made of the remainder4 ,starch being insoluble1 it cannot be determined directly by its rotatory power4 ,when heated for a few hours in contact with water at a high pressure1 starch becomes soluble1 and in this state has a fairly constant gyrodynat1 viz41 a,d #aig4 ,starch is also rendered soluble by rubbing it in a mortar for about ten minutes with an excess of strong hydrochloric acid1 and in this way a quick approximate idea may be obtained of the percentage present4 ,starch prepared in this manner1 however1 has a strong reducing power on metallic salts1 showing that a part of it has already1 even in so short a time1 assumed the state of maltose or dextrose4 ,the gyrodynat of pure anhydrous starch in such conditions varies from a,d #aig to a,d #aid4 ,starch is also rendered soluble by boiling with salicylic acid1 whereby a solution is obtained having a gyrodynat of a,d #bjj7;circa74 ,the methods of procedure for the analysis of starch will be set forth in detail in the following paragraphs4 #ahc4 ,estimation of ,water4--,in prepared or commercial starches the water may be determined by heating in a partial vacuum4 ,the temperature at first should be low1 not exceeding #fj4 ,after drying for an hour at that heat the temperature may be gradually increased4 ,the last traces of water come off from starch with difficulty1 and the final temperature may be carried a little beyond #ajj without danger of decomposition4 ,ost recommends the use of an atmosphere of hydrogen or illuminating gas4#adh ,one and a half grams of the finely powdered sample are placed in the drying tube described in paragraph #bc1 and heated in a stream of dry hydrogen4 ,the temperature at first is kept at about #fj for several hours and is then gradually increased to #abj4 ,ost states that even at #aej the sample preserves its pure white color1 but so high a temperature is not necessary4 ,maercker1 at the ,halle station1 makes use of the same process1 but employs illuminating gas instead of hydrogen4 ,the importance of beginning the desiccation at a low temperature arises from the fact that at a higher temperature1 before the greater part of the water is driven off1 the starch will suffer a partial fusion and form a paste which is very difficult to dry4 ,the dried sample must be kept in a stoppered vessel to prevent the absorption of hygroscopic moisture4 #ahd4 ,estimation of ,ash4--,when the drying is accomplished in a flat platinum dish1 the same sample may serve for incineration4 ,otherwise the incineration may be accomplished in another portion of the sample by following directions already given4#adi #ahe4 ,nitrogen4--,even very pure samples of starch may contain a little nitrogen which is most conveniently determined by moist combustion4#aej ,as a rule1 in commercial starches of good quality1 the quantity of pure starch may be considered to be the remainder after subtracting the sum of the weights of water1 ash and nitrogen multiplied by #f4be1 from the original weight of the sample taken4 ,example3-- ,per cent of moisture found #ab4he 0 0 0 ash found #j4jh 0 0 0 nitrogen #f4be #j4bg ----- ,sum #ac4bj ,per cent of pure starch in sample #hf4hj ,samples of starch usually contain also traces of fat and fiber1 and these when present in weighable quantities1 should be determined and proper deductions made4 #ahf4 ,hydrolysis with ,acids4--,the acids commonly chosen for hydrolyzing starch are sulfuric and hydrochloric4 ,the former has the advantage of being more easily removed from the finished product but the latter performs the work with less damage to the sugars formed4 ,for commercial purposes sulfuric and for analytical practice hydrochloric acids are commonly employed4 ,illustration3 ,,figure #dg 7,,bis74 ,,maercker',s ,,hydrolyzing ,,apparatus ,,for ,,starch4 ,the best process for analytical purposes is the one proposed by ,sachsse4#aea ,in this method the starch is heated with the hydrolyzing mixture in the proportion of three grams to #bjj cubic centimeters of water and twenty of hydrochloric acid of #a4abe specific gravity1 containing five and six-tenths grams of the pure gas4 ,the heating is continued for three hours on a steam-bath4 ,maercker recommends1 instead of the above procedure1 heating for two hours at gentle ebullition in an oil-bath4 ,in this method three grams of the starch are reduced to paste with #bjj cubic centimeters of water1 and then boiled for two hours with fifteen cubic centimeters of hydrochloric acid of #a4abe specific gravity4 ,the erlenmeyers in which the hydrolysis takes place are heated in an oil-bath and are provided with reflux condensers made of long glass tubes on which some bulbs have been blown1 as shown in the accompanying figure4 ,in all cases after hydrolysis the solution is neutralized1 made to a standard volume and an aliquot part1 after filtration1 diluted to contain an amount of dextrose suited to the use of the table by ,allihn for calculating the percentage of sugar4 ,in diluting the solution preparatory to the estimation of dextrose1 it is well to remember that nine parts of starch will furnish theoretically ten parts of dextrose4 ,since three grams of the sample are used1 containing approximately eighty-five per cent of starch1 the quantity of dextrose present is a little less than three grams4 ,the solution should therefore contain not less than #cjj cubic centimeters4 #ahg4 ,factor for ,calculating ,starch from the ,dextrose ,obtained4--,if all the starch could be converted into dextrose without loss1 the quantity of it could be easily calculated theoretically on the supposition that the formula of starch is 7,c,h,o74 ,the factor by this assumption is1 starch dextrose #j4ij4 ,if the starch have the formula assigned to it by ,ngeli1 viz41 ,c,h,o the formula becomes1 starch dextrose #j4iah4 ,ost prefers to work by ,sachsse's method and to use the factor #j4ibe to convert the dextrose into starch4#aeb ,in view of all the facts in the case it appears that the analyst will reach nearly correct results by converting the starch into dextrose by heating for three hours at #ajj with hydrochloric acid or for two hours at gentle ebullition as directed above1 determining the resultant dextrose and multiplying the weight thereof by #j4ib4 #ahh4 ,polarization of ,starch4--,starch may be prepared for polarization by dissolving it in cold hydrochloric acid4 ,the process as carried out by ,effront is as follows4#aec ,five grams of starch are rubbed with twenty cubic centimeters of cold concentrated hydrochloric acid for nearly ten minutes or until the solution is quite clear4 ,the volume is completed to #bjj cubic centimeters with water and the solution polarized4 ,by this process there is always produced a notable quantity of reducing sugars1 and for this reason it must be admitted that a portion of the starch has suffered complete hydrolysis4 ,ost therefore recommends the use of an acid of #a4ag specific gravity1 and the gyrodynat of the soluble starch thus produced is found to vary from a,d #aif4c to #aif4g4 ,when acid of #a4bj specific gravity is employed the gyrodynat falls to a,d #aid4b4aed ,for approximately correct work the solution with the weaker hydrochloric acid and subsequent polarization is to be recommended as the most rapid method for starch determination4 ,it will be of interest to add the observation that the gyrodynat of maltose has lately been redetermined by ,ost1 who finds it to be a,d #acg4jd #j4ai4aee #ahi4 ,solutions of ,starch at ,high ,pressure4--,starch may also be brought into a condition suited to polarization by dissolving in water at a high temperature and pressure4 ,the solution is accomplished in an autoclave as described in #aha4 ,from two to three grams of starch are used and from eighty to ninety cubic centimeters of water4 ,the starch is first reduced to a pasty state by heating with the water and1 when evenly distributed throughout the flask1 is rendered soluble by heating from three to five hours in an autoclave at from two to three atmospheres4 ,the material is entirely without action on an alkaline copper solution4 ,after heating1 the volume of the solution is completed to #ajj cubic centimeters and it is then polarized4 ,the gyrodynat of starch dissolved in this way varies from a,d #aif4e to #aig4aef ,starch is prepared by ,baudry for polarization by boiling with salicylic acid4#aeg ,the gyrodynat of starch dissolved in this way is a,d #bjj4be4 #aij4 ,polarization after ,solution in ,dilute ,nitric ,acid4--,guichard recommends saccharification with ten per cent nitric acid 7ten cubic centimeters strong acid1 ninety cubic centimeters water74#aeh ,this treatment1 even after prolonged boiling1 gives only a light straw color to the solution which does not interfere with its polarization with a laurent instrument4 ,in working on cereals four grams of the finely ground material1 in which the bran and flour are intimately mixed1 are used4 ,the material is placed in a flask of about #ejj cubic centimeters capacity1 with #ajj cubic centimeters of the dilute acid4 ,the flask is closed with a stopper carrying a reflux condenser4 ,after boiling for an hour the contents of the flask are filtered and examined in the saccharimeter4 ,the dextrose formed is determined by the polarimetric data and the quantity of starch transformed calculated from the dextrose4 ,the following formula is used3 av #be #j4jaf ,a ------------------4 #b #eb4h ,in this formula a the rotation in angular degrees1 v the volume of the liquid and ,a the starch transformed4 ,in this method no account is taken of the sucrose and other sugars which are present in cereals4 ,in the case of sucrose the left-handed sugar produced by treatment with nitric acid would diminish the rotation to the right and thus introduce an error4 ,on the other hand the dextrose formed from the fiber of the bran would be calculated as starch4 ,if these two errors should be compensating the method might prove practical4 #aia4 ,rapid ,estimation ,of ,starch4--,for the rapid estimation of starch in cereals1 cattle foods and brewery refuse1 ,hibbard recommends a method which is carried out as follows3 ,the malt extract is prepared by covering ground1 dry malt with water containing from fifteen to twenty per cent of alcohol4 ,the object of adding alcohol is to preserve the filtered extract4 ,it exercises a slight retarding effect on the action of the diastase1 but prevents the malt extract from fermenting4 ,after standing for a few hours in contact with the malt1 the liquid is separated by filtration and is then ready for use4 ,the substance in which the starch is to be determined should be dry enough to be finely pulverized1 but previous extraction with ether is omitted4 ,enough of the material to contain at least half a gram of starch is placed in a flask with fifty cubic centimeters of water and from one to two cubic centimeters of malt extract added4 ,the mixture is at once heated to boiling with frequent shaking to prevent the formation of clots4 ,the addition of the diastase before boiling is to aid in preventing the formation of lumps4 ,after boiling a minute the mixture is cooled to #fj and from two to three cubic centimeters of the malt extract added4 ,it is then slowly heated until it again boils1 consuming about fifteen minutes1 when1 after cooling1 it is tested with iodin for starch4 ,if a blue color be produced the operation above described is repeated until it fails to reappear4 ,the mixture is then made up to a standard volume1 thrown on a linen filter and an aliquot part of the filtrate1 representing from #bjj to #cjj milligrams of starch1 is boiled with five cubic centimeters of hydrochloric acid1 of thirty per cent strength1 for half an hour4 ,the total volume of the liquid before boiling should be completed to sixty cubic centimeters4 ,by the method above described1 it is claimed that the determination of starch in a cereal or similar substance can be completed within two hours4 ,the chief amount of time saved is in the heating with the malt extract1 which instead of being continued for two hours1 as usually directed1 can be accomplished in thirty minutes4#aei #aib4 ,precipitation of ,starch with ,barium ,hydroxid4--,the tendency of carbohydrate bodies to unite with the earthy bases has been utilized by ,asboth as a basis for the quantitive determination of starch4#afj ,about three grams of the finely ground sample containing the starch1 or one gram of pure starch1 are rubbed up in a mortar with water and the detached starch remaining suspended in the wash water is poured off4 ,this operation is repeated until all the starch is removed4 ,in difficult cases hot water may be used4 ,the starch thus separated is heated in a quarter liter flask to the boiling point to reduce it to the condition of paste4 ,when the paste is cold it is treated with fifty cubic centimeters of the barium hydroxid solution1 the flask closed and well shaken for two minutes4 ,the volume is then completed to the mark with forty-five per cent alcohol1 the flask well shaken and allowed to stand4 ,in a short time the barium-starch compound separates and settles4 ,fifty cubic centimeters of the clear supernatant liquor are removed with a pipette1 or the liquor may be passed through a filter and the quantity mentioned removed for titration of the residual barium hydroxid after the addition of a few drops of phenolphthalein solution4 ,the quantity of barium hydroxid remaining1 deducted from the original quantity1 gives the amount which has entered into composition with the starch2 the composition of the molecule being ,ba,o,c,h,o1 which contains #ai4aj per cent of barium oxid and #hj4ij per cent of starch4 ,the set solution of barium hydroxid must be preserved from contact with the carbon dioxid of the air4 ,the burette should be directly attached to the bottle holding the set solution1 by any of the usual appliances1 and the air entering the bottle must be deprived of carbon dioxid4 ,the water used in the work must be also free of air1 and this is secured by boiling immediately before use4 ,example4--,a sample of flour selected for the analysis weighed #c4bab grams4 ,the starch was separated and reduced to paste in the manner described above4 ,thirty and four-tenths cubic centimeters of tenth-normal hydrochloric acid were exactly neutralized by ten cubic centimeters of the barium hydroxid solution4 ,after treatment as above described1 fifty cubic centimeters of the clear liquor1 corresponding to ten cubic centimeters of the added barium hydroxid1 required #ai4je cubic centimeters of tenth-normal hydrochloric acid4 ,then #cj4d - #ai4je #aa4ce1 and #aa4ce x #e #ef4ge1 which number corresponds to the total titration of the residual barium hydroxid in terms of tenth-normal hydrochloric acid4 ,this number multiplied by #j4jcbd1 viz41 starch corresponding to one equivalent of barium1 gave #a4hchg grams of starch or #eg4bd per cent of the weight of flour employed4 ,the barium hydroxid method has been given a thorough trial in this laboratory and the results have been unsatisfactory when applied to cereals4 ,the principle of the process1 however1 appears to be sound1 and with a proper variation of working details1 it may become practical4 #aic4 ,disturbing ,bodies in ,starch ,determinations4--,stone has made a comparison of the standard methods of starch determinations1 and the results of his work show that in the case of pure starch all of the standard methods give approximately correct figures4 ,for instance1 in the case of a pure potato starch1 the following data were obtained3 ,by inversion with hydrochloric acid1 #he4ge per cent2 by inversion with oxalic and nitric acids1 #he4ge per cent2 by solution in salicylic acid1 #he4dg per cent2 and by precipitation with barium hydroxid1 #he4eh per cent4#afa ,when these methods are used1 however1 for the determination of starch in its original state1 the widest variations are secured4 ,stone shows that these variations are due chiefly to the inverting effect of the reagents employed upon the pentosans present4 ,in experiments made with pure xylan obtained from wheat straw1 the methods employed gave from #dd4gc to #fg4af per cent of material1 which would be calculated by the usual methods as starch4 ,stone also shows that the pentosans are practically unaffected by the action of diastase or malt extract4 ,pure xylan treated with diastase1 under the condition in which starch is converted into maltose and other soluble carbohydrates1 fails to give any subsequent reaction whatever with alkaline copper solution4 ,in all cases1 therefore1 where starch occurs in conjunction with pentose bodies1 it is necessary to separate it by diastatic action before applying any of the methods of conversion of the starch into dextrose or its precipitation by barium hydroxid4 #aid4 ,colorimetric ,estimation of ,starch4--,the production of the intensely blue color which starch gives with iodin has been used not only as the basis of a qualitive method1 but also of many attempts at quantitive determination4 ,these attempts have1 as a rule1 been attended with very unsatisfactory results1 due both to the extraordinary delicacy of the reaction and to the fact that starches of different origin do not always give exactly the same intensity of tint when present in the same quantity4 ,at the present it must be admitted that little should be expected of any quantitive colorimetric test4 ,in case such a test is desired the procedure described by ,dennstedt and ,voigtlnder may be followed4#afb ,a weighed quantity of the starch-holding material1 containing approximately half a gram of starch1 is placed in a two liter flask and boiled with a liter of water4 ,after cooling1 the volume is completed to two liters and the starch allowed to subside4 ,five cubic centimeters of the clear supernatant liquor are placed in a graduated cylinder holding #ajj1 and marked in half cubic centimeters4 ,one drop of a solution of iodin in potassium iodid is added and the volume completed to the mark4 ,a half gram of pure starch is treated in the same way and different measured portions of the solution treated as above until the color of the first cylinder is matched4 ,from the quantity of pure starch in the matched cylinder the quantity in the sample is determined4 ,the test should be made in duplicate or triplicate4 ,if a violet color be produced instead of a blue1 it may be remedied by treating the sample with alcohol before the starch granules are dissolved4 #aie4 ,fixation of ,iodin4--,in addition to forming a distinctive blue color with iodin1 starches have the power of fixing considerable quantities of that substance4 ,the starches of the cereals have this power in a higher degree than those derived from potatoes4 ,in presence of a large excess of iodin the starches of rice and wheat have a maximum iodin-fixing power of about nineteen per cent of their weight4 ,when only enough of iodin is employed to enter into combination the percentage absorbed varies from nine to fifteen per cent4 ,the absorption of iodin by starches is a matter of importance from a general chemical standpoint1 but as at present determined has but little analytical value4 ,it is evident1 however1 that this absorption must take place according to definite chemical quantities and the researches of investigators may in the future discover some definite quantitive method of measuring it4#afc #aif4 ,identification of ,starches of ,different ,origin4--,it is often important1 especially in cases of suspected adulteration1 to determine the origin of the starch granules4 ,for this purpose the microscope is the sole resort4 ,in many cases it is easy to determine the origin of the starch by the size or the shape and marking of the grains4 ,in mixtures of more than one kind of starch the distinguishing features of the several starches can be clearly made out in most instances4 ,there are1 however1 many instances where it is impossible to discriminate by reason of the fact that the characteristics of starch granules vary even in the same substance and from year to year with varying conditions of culture4 ,in many cases the illustrations of the forms and characteristics of starch granules which are found in books are misleading and no reliance can be placed on any illustrations which are not either photographs or drawings made directly from them4 ,in the microscopic study of starches the analyst will be greatly helped by the following descriptions of the characteristic appearance of the granules and the classifications based thereon4#afd #aig4 ,vogel's ,table of the ,different ,starches and ,arrowroots of ,commerce4--,a4 ,granules simple1 bounded by rounded surfaces4 ,i4 ,nucleus central1 layers concentric4 a4 ,mostly round1 or from the side1 lens-shaped4 #a4 ,large granules #j4jcif-j4jebh mm1 rye starch3 #b4 ,large granules #j4jceb-j4jcif mm1 wheat starch3 #c4 ,large granules #j4jbfd mm1 barley starch4 b4 ,egg-shaped1 oval1 kidney-shaped3 ,hilum often long and ragged3 #a4 ,large granules #j4jcb-j4jgi mm1 leguminous starches4 ,,ii4 ,nucleus eccentric1 layers plainly eccentric or meniscus-shaped4 a4 ,granules not at all or only slightly flattened3 #a4 ,nucleus mostly at the smaller end2 #j4jf-j4aj mm1 potato starch3 #b4 ,nucleus mostly at the broader end or towards the middle in simple granules2 #j4jbb-j4jfj mm1 maranta starch4 b4 ,granules more or less strongly flattened4 #a4 ,many drawn out to a short point at one end4 a4 ,at most #j4jfj mm long1 curcuma starch3 b4 ,as much as #j4acb mm long1 canna starch3 #b4 ,many lengthened to bean-shaped1 disk-shaped1 or flattened2 nucleus near the broader end2 #j4jdd-j4jge mm1 banana starch3 #c4 ,many strongly kidney-shaped2 nucleus near the edge2 #j4jdh-j4jef mm1 sisyrinchium starch3 #d4 ,egg-shaped2 at one end reduced to a wedge1 at the other enlarged2 nucleus at smaller end2 #j4je-j4jg mm1 yam starch3 ,b4 ,granules simple or compound1 single granules or parts of granules1 either bounded entirely by plain surfaces1 many-angled1 or by partly round surfaces4 ,i4 ,granules entirely angular4 #a4 ,many with prominent nucleus3 ,at most #j4jjff mm1 rice starch3 #b4 ,without a nucleus3 ,the largest #j4jjhh mm1 millet starch3 ,,ii4 ,among the many-angled also rounded forms4 a4 ,no drum-shaped forms present1 angular form predominating4 #a4 ,without nucleus or depression very small2 #j4jjdd mm1 oat starch3 #b4 ,with nucleus or depression2 #j4jacb-j4jbbj mm4 a4 ,nucleus or its depression considerably rounded2 here and there the granules united into differently formed groups2 buckwheat starch3 b4 ,nucleus mostly radiate or star-shaped2 all the granules free2 maize 7corn7 starch3 b4 ,more or less numerous kettledrum and sugar-loaf like forms4 #a4 ,very numerous eccentric layers2 the largest granules #j4jbb-j4jceb mm1 batata 7sweet potato7 starch3 #b4 ,without layers or rings2 #j4jjh-j4jbb mm4 a4 ,in the kettledrum-shaped granules the nucleal depression mostly widened on the flattened side2 #j4jjh-j4jbb mm1 cassava starch3 b4 ,depression wanting or not enlarged4 aa4 ,nucleus small1 eccentric2 #j4jjh-j4jaf mm1 pachyrhizus starch3 bb4 ,nucleus small1 central1 or wanting4 aaa4 ,many irregular angular forms2 #j4jjh-j4jagf mm1 sechium starch3 bbb4 ,but few angular forms2 some with radiate1 nucleal fissure2 #j4jjh-j4jagf mm1 chestnut starch4 ,c4 ,granules simple and compound2 predominant forms1 oval1 with eccentric nucleus and numerous layers2 the compound granule made up of a large granule and one or more relatively small kettledrum-shaped ones2 #j4jbe-j4jff mm1 sago starch4 #aih4 ,muter's ,table for the ,detection of ,starches when ,magnified about #bcj ,diameters4 ,all measurements are given in decimals of an inch4 ,group ,i3 ,all more or less oval in shape and having both hilum and rings visible4 ---------------------------------------- ------------------------- ,name4 ,shape4 ,normal ,remarks4 measurements4 ---------------------------------------- ------------------------- ,tous les mois,oval1 with flat #j4jjcgj ,hilum annular1 near one ends to #j4jjahe end and incomplete rings4 ,potato ,oval #j4jjbgj ,hilum annular1 rings to #j4jjadh incomplete1 shape and size very variable4 ,bermuda ,sack-shaped #j4jjadh ,hilum distinct annular1 arrowroot to #j4jjabi shape variable1 rings faint4 ,st4 ,vincent ,oval-oblong #j4jjadh ,hilum semi-lunar1 rings arrowroot to #j4jjabi faint1 shape not very variable4 ,natal ,broadly ovate #j4jjadh ,hilum annular1 in arrowroot to #j4jjabi center and well marked complete rings4 ,galangal ,skittle-shaped ,about #j4jjace;,hilum elongated1 very faint incomplete rings4 ,calumba ,broadly 0 #j4jjahe;,hilum semi-lunar1 faint pear-shaped but complete rings1 shape variable4 ,orris root ,elongated-oblong 0 #j4jjjib;,hilum faint1 shape characteristic4 ,turmeric ,oval-oblong1 0 #j4jjadh,very strongly marked conical incomplete rings4 ,ginger ,shortly conical1 0 #j4jjadh;,hilum and rings with rounded scarcely visible1 angles4 shape variable but characteristic4 ---------------------------------------- --------------------------- ,group ,,ii3 ,with strongly developed hilum more or less stellate4 ---------------------------------------- ------------------------- ,name4 ,shape4 ,normal ,remarks4 measurements4 ---------------------------------------- ------------------------- ,bean ,oval-oblong ,about #j4jjace;,fairly uniform4 ,pea ,like bean #j4jjaaa ,very variable in size1 to #j4jjjgd with granules under #j4jjaaa preponderating4 ,lentil ,like bean ,about #j4jjaaa;,hilum1 a long depression seldom radiate4 ,nutmeg ,rounded 0 #j4jjjee,the small size and rounded form distinctive4 ,dari ,elongated 0 #j4jjjgd;,irregular appearance and hexagon great convexity distinctive4 ,maize ,round and 0 #j4jjjgd,the rounded angles of the polygonal polygonalgranules distinctive4 ---------------------------------------- ------------------------- ,group ,,iii3 ,hilum and rings practically invisible4 ---------------------------------------- ------------------------- ,name4 ,shape4 ,normal ,remarks4 measurements4 ---------------------------------------- ------------------------- ,wheat ,circular and #j4jjahe ,very variable in size and flat to #j4jjjji very dull polarization in water4 ,barley ,slightly ,about #j4jjjgc,the majority measuring angular about #j4jjcgc circles distinctive1 and a few four times this size4 ,rye ,like barley #j4jjadh ,small granules1 quite to #j4jjjji round1 and here and there cracked4 ,jalap ,like wheat ,polarizes brightly in water4 ,rhubarb do4 #j4jjjee ,polarizes between jalap to #j4jjjcc and wheat1 and runs smaller and more convex4 ---------------------------------------- ------------------------- ,senega ,like wheat #j4jjadh- #j4jjjji ,bayberry do4 #j4jjjgd- ,measurements the #j4jjjaa only guide4 ,sumbul do4 #j4jjjgd- #j4jjjji ---------------------------------------- ------------------------- ,chestnut ,very variable #j4jjjij- ,variable form1 and small #j4jjjji but regular size1 distinctive4 ,acorn ,round-oval ,about #j4jjjgd,small and uniform size1 distinctive4 ,calabar bean ,oval-oblong #j4jjbif ,large size and shape to #j4jjahj characteristic4 ,licorice ,elongated-oval,about #j4jjjah,small size and shape distinctive4 ,hellebore ,perfectly #j4jjjcg ,small1 regular size and 7green or rotund to #j4jjjji rotundity1 distinctive4 black7 ,hellebore ,irregular #j4jjjee ,irregular shape and faint 7white7 to #j4jjjji central depression1 distinctive4 ---------------------------------------- ------------------------- ,group ,,iv3 ,more or less truncated at one end4 ---------------------------------------- ------------------------ ,name4 ,shape4 ,normal ,remarks4 measurements4 ---------------------------------------- ------------------------ ,cassia ,round #j4jjaaa ,round or muller shaped to #j4jjjah granules and faint circular hilum4 ,cinnamon ,like cassia #j4jjjgd ,more frequently truncated to #j4jjjji than cassia1 and smaller4 ,sago 7raw7 ,oval-ovate #j4jjbfj ,has circular hilum at to #j4jjaaa convex end and rings faintly visible4 ,sago 0 #j4jjbfj ,has a large oval or 7prepared7 to #j4jjaaa circular depression1 covering one-third nearly of each granule4 ,tapioca ,roundish #j4jjjgd ,a little over fifty per to #j4jjjee cent truncated by one facet1 and a pearly hilum4 ,arum ,like tapioca ,about #j4jjjef,smaller than tapioca and truncated by two facets4 ,belladonna do4 ,not distinguishable from tapioca4 ,colchicum do4 ,about #j4jjjgd,larger than tapioca1 and contains many more truncated granules4 ,scammony do4 0 #j4jjjde,smaller than tapioca1 more irregular1 and hilum not visible4 ,cancella ,very variable #j4jjjcc- ,very variable1 form and #j4jjjbb small size the only points4 ,podophyllum ,like tapioca ,about #j4jjjdj,like scammony1 but has visible hilum in most of the granules4 ,aconite do4 0 #j4jjjcg,like tapioca1 but half the size4 ---------------------------------------- ------------------------ ,group ,v3 ,all granules more or less polygonal4 ---------------------------------------- ------------------------- ,name4 ,shape4 ,normal ,remarks4 measurements4 ---------------------------------------- ------------------------- ,tacca ,poly- or #j4jjjge ,distinguished from maize hexagonal to #j4jjjcg by its sharp angles4 ,oat ,polygonal ,about #j4jjjcg,larger than rice and hilum visible in some granules4 ,rice do4 #j4jjjcj- ,measurement using #j4jjjbj one-eighth or one-twelfth inch power1 and then hilum visible4 ,pepper do4 #j4jjjbj- ,do4 #j4jjjjb ,ipecacuanha do4 ,about #j4jjjah,some round and truncated granules1 adhering in groups of three4 ---------------------------------------- ------------------------- #aii4 ,blyth's ,classification4--,blyth gives the following scheme for the identification of starch granules by their microscopic appearance4#afe ,division ,i4--,starches showing a play of colors with polarized light and selenite plate3 ,the hilum and concentric rings are clearly visible1 and all the starch granules1 oval or ovate4 ,canna arrowroot1 potato1 arrowroot1 calumba1 orris root1 ginger1 galangal and turmeric belong to this division4 ,division ,,ii4--,starches showing no iridescence1 or scarcely any1 when examined by polarized light and selenite3 ,class ,i4--,the concentric rings are all but invisible1 and the hilum stellate4 ,the bean1 pea1 maize1 lentil1 dari and nutmeg starches are in this class4 ,class ,,ii4--,starches which have both the concentric rings and hilum invisible in the majority of granules3 this important class includes wheat1 barley1 rye1 chestnut1 acorn1 and many starches in medicinal plants4 ,class ,,iii4--,all the granules are truncated at one end4 ,this class includes sago1 tapioca and arum1 several drugs and cinnamon and cassia4 ,class ,,iv4--,in this class all the granules are angular in form and it includes oats1 tacca1 rice1 pepper and ipecacuanha4 #bjj4 ,preparation of ,starches for ,microscopical ,examination4--,the approximately pure starches of commerce may be prepared for microscopic examination by rubbing them up with water and mounting some of the suspended particles by one of the methods to be described below4 ,in grains1 seeds and nuts the starch is separated by grinding with water and working through fine linen4 ,the starch which is worked through is allowed to subside1 again beaten up with water if necessary and the process continued until the grains are separated sufficiently for microscopic examination4 ,a little potash or soda lye may be used1 if necessary1 to separate the granules from albuminous and other adhering matter4 ,the analyst should have a collection of samples of all common starches of known origin for purposes of comparison4 ,the granules are mounted for examination by plain light in a medium of glycerol and camphor water4 ,when polarized light is used the mounting should be in ,canada balsam4#aff ,the reader can find excellent photomicrographs of the more common starches in ,griffith's book4#afg #bja4 ,appearance in ,balsam with ,polarized ,light4--,mounted in balsam the starches are scarcely visible under any form of illumination with ordinary light1 the index of refraction of the granules and the balsam being so nearly alike4 ,when1 however1 polarized light is used the effect is a striking one4 ,it is very easy to distinguish all the characteristics1 except the rings1 the center of the cross being at the nucleus of the granule4 ,with the selenite plate a play of colors is produced1 which is peculiar to some of the starches and forms the basis of ,blyth's classification4 #bjb4 ,description ,of ,typical ,starches4--,the more commonly occurring starches are described by ,richardson as they appear under the microscope magnified about #cej diameters4#afh ,the illustrations1 with the exception of the cassava starch1 and the maize starch accompanying it were drawn by the late ,dr4 ,geo4 ,marx from photographs made by ,richardson in this laboratory4 ,the two samples excepted were photographed for the author by ,dr4 ,g4 ,l4 ,spencer4 ,maranta ,starch4--,of the same type as the potato starch are the various arrowroots1 the only one of which commonly met with in this country being the ,bermuda1 the starch of the rhizome of ,maranta arundinacea1 and the starch of turmeric4 ,the granules are usually not so varied in size or shape as those of the potato1 averaging about #j4jg millimeter in length as may be seen in ,fig4 #dh4 ,they are about the same size as the average of the potato1 but are not often found with the same maximum or minimum magnitude1 which circumstance1 together with the fact that the end at which the nucleus appears is broader in the maranta and more pointed in the potato1 enables one to distinguish the two starches without difficulty4 ,with polarized light the results are similar to those seen with potato starch1 and this is a ready means of distinguishing the two varieties1 by displaying in a striking way the form of the granule and position of the hilum4 ,potato ,starch4--,the starch grains of the potato are very variable in size1 being found from #j4je to #j4aj millimeter in length1 and in shape from oval and allied forms to irregular and even round in the smallest4 ,these variations are illustrated in ,fig4 #di1 but the frequency of the smaller granules is not as evident as in some other cases4 ,the layers are visible in some granules with great distinctness and in others hardly at all1 being rather more prominent in the starch as obtained from a freshly cut surface4 ,the rings are more distinct1 too1 near the hilum or nucleus1 which in this1 as in all tuberous starches1 is eccentric1 shading off toward the broader or more expanded portion of the granule4 ,the hilum appears as a shadowy depression1 and with polarized light its position is well marked by the junction of the arms of the cross4 ,with polarized light and a selenite plate a beautiful play of colors is obtained4 ,the smaller granules1 which are nearly round1 may readily be confused with other starches1 but their presence serves at once to distinguish this from maranta or ,bermuda arrowroot starch4 ,rarely compound granules are found composed of two or three single ones each with its own nucleus4 ,ginger ,starch4--,this starch is of the same class as those from the potato and maranta and several others which are of underground origin4 ,in outline the granules are not oval like those named1 but more rectangular1 having more obtuse angles in the larger ones and being cylindrical or circular in outline in the smaller1 as indicated in ,fig4 #ej4 ,they average nearly the same size as maranta starch1 but are much more variable1 both in size and form4 ,the rings are scarcely visible even with the most favorable illuminations4 ,sago ,starch4--,this exists in two modifications in the market2 as raw and as prepared sago4 ,in the prepared condition it is characterized by a larger circular depression in the center of most of the granules4 ,the rings are not visible4 ,they are mostly circular in form or approaching it1 and vary from #j4jbe to #j4jfe millimeter in diameter1 as indicated in ,fig4 #ea4 ,illustration3 ,,fig4 #dh4 ,,maranta ,,starch #cej4 ,illustration3 ,,fig4 #di4 ,,potato ,,starch #cej4 ,illustration3 ,,fig4 #ej4 ,,ginger ,,starch #cej4 ,illustration3 ,,fig4 #ea4 ,,sago ,,starch #cej4 ,illustration3 ,,fig4 #eb4 ,,pea ,,starch #cej4 ,illustration3 ,,fig4 #ec4 ,,bean ,,starch #cej4 ,,drawn ,,by ,,geo4 ,,marx4 ,a4 ,hoen ,co41 ,lithocaustic ,illustration3 ,,fig4 #ed4 ,,wheat ,,starch #cej4 ,illustration3 ,,fig4 #ee4 ,,barley ,,starch #cej4 ,illustration3 ,,fig4 #ef4 ,,rye ,,starch #cej4 ,illustration3 ,,fig4 #eg4 ,,oat ,,starch #cej4 ,illustration3 ,,fig4 #eh4 ,,indian ,,corn ,,starch #cej4 ,illustration3 ,,fig4 #ei4 ,,rice ,,starch #cej4 ,,drawn ,,by ,geo4 ,,marx4 ,a4 ,hoen ,co41 ,lithocaustic ,illustration3 ,,fig4 #fj4 ,,cassava ,,starch #aej4 ,,plain ,,illumination4 ,illustration3 ,,fig4 #fa4 ,,indian ,,corn ,,starch #aej4 ,,plain ,,illumination4 ,a4 ,hoen ,co41 ,lithocaustic ,pea and ,bean ,starches4--,these starches produce but a slight effect with polarized light4 ,the rings are scarcely visible1 and the hilum is stellate or much cracked along a median line1 the bean more so than the pea1 the latter resembling fresh dough kneaded again into the center as in making rolls1 and the former the shape assumed by the same after baking4 ,the grains of both are somewhat variable in size1 ranging from #j4jbe to #j4aj millimeter in length1 as shown in ,figs4 #eb and #ec4 ,wheat ,starch grains are quite variable in size1 varying from #j4je to #j4jaj millimeter in diameter4 ,they belong to the same class as barley and rye1 the hilum being invisible and the rings not prominent4 ,the granules are circular disks in form1 and there are now and then contorted depressions resembling those in pea starch4 ,they are the least regular of the three starches named and do not polarize actively4 ,the typical forms of these granules are shown in ,fig4 #ed4 ,barley ,starch is quite similar to that of wheat1 but the grains do not vary so much in size1 averaging #j4je millimeter4 ,they have rings which are much more distinct1 and very small granules adhering to the largest in bud-like forms1 as seen in ,fig4 #ee4 ,rye ,starch is more variable in size1 many of the granules not exceeding #j4jb millimeter1 while the largest reach #j4jf to #j4jg millimeter4 ,it lacks distinctive characteristics entirely1 and is the most simple in form of all the starches4 ,fig4 #ef shows the appearance of the granules under the microscope4 ,oat ,starch is unique1 being composed of large compound masses of polyhedral granules from #j4ab to #j4jb millimeter in length1 the single granules averaging #j4jb to #j4jae millimeter4 ,it does not polarize actively1 and displays neither rings nor hilum4 ,the illustration1 ,fig4 #eg1 shows its nature with accuracy4 ,indian ,corn ,starch4--,the granules of maize starch are largely of the same size1 from #j4jb to #j4jc millimeter in diameter1 with now and then a few which are much smaller4 ,they are mostly circular in shape or rather polyhedral1 with rounded angles1 as shown in ,figs4 #eh and #fa4 ,they form very brilliant objects with polarized light1 but with ordinary illumination show but the faintest sign of rings and a well-developed hilum1 at times star-shaped1 and at others more like a circular depression4 ,rice ,starch is very similar to that of maize1 and is easily confused with it1 the grains being about the same size4 ,the grain1 however1 is distinguished from it by its polygonal form1 and its well defined angles1 as indicated in ,fig4 #ei4 ,the hilum is more prominent and more often stellate or linear4 ,several granules are at times united4 ,cassava ,starch4--,this variety of starch is obtained from the root of the sweet cassava1 which grows in great profusion in ,florida4 ,it is compared with maize starch in ,figs4 #fj and #fa4 ,in the illustration the granules are represented as magnified #aej diameters4 ,the grains of the cassava starch measure about #j4jab millimeter in diameter and resemble very nearly maize starch1 except that they have greater evenness of outline4#afi ,for further descriptions of starch grains the reader is referred to the work of ,griffith1 already cited4 ,these descriptions1 it will be seen1 do not agree entirely with those of some other authors1 but they are based on a somewhat extensive experience4 ,there are peculiarities of size1 shape and appearance of starch granules1 which must be allowed for1 and the necessity for every investigator to compare a starch which he is desirous of identifying with authentic specimens1 must always be recognized4 ,,authorities ,,cited ,,in ,,part ,,second4 #bc ,vines1 ,vegetable ,physiology4 #bd ,berichte der deutschen chemischen ,gesellschaft1 ,band #bc1 ,s4 #bacf2 ,stone1 ,agricultural ,science ,vol4 #f1 p4 #ahj4 ,page #ei1 eighth line from bottom insert 8original0 before 8optical40 ,page #fj1 second line from top1 read d instead of l fructose4 #be ,herles1 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahij4 ,s4 #bag4 #bf ,tucker2 ,wiechmann2 ,sidersky2 von ,lippman2 ,tollens and ,spencer4 #bg ,bulletin ,no4 #bh1 ,department of ,agriculture1 ,division of ,chemistry1 p4 #aig4 #bh ,physikalisch-,chemische ,tabellen1 ,s4 #db4 #bi ,tucker's ,manual of ,sugar ,analysis1 pp4 #ajj et seq4 #cj ,vid4 op4 cit4 supra1 p4 #ajh4 #ca ,op4 cit4 supra1 p4 #aji4 #cb ,op4 cit4 supra1 p4 #aaj4 #cc ,op4 cit4 supra1 p4 #aad4 #cd ,spencer's ,handbook for ,sugar ,manufacturers1 p4 #ib4 #ce ,landolt's ,handbook of the ,polariscope1 pp4 #ie et seq4 #cf ,robb1 vid4 op4 cit4 supra1 p4 #h4 #cg ,spencer's ,handbook for ,sugar ,manufacturers1 pp4 #bb et seq4 ,tucker's ,manual of ,sugar ,analysis1 pp4 #abj et seq4 #ch ,sidersky2 ,trait d',analyse des ,matires ,sucres1 p4 #ajd4 #ci ,journal of the ,american ,chemical ,society1 #ahic4 ,vol4 #ae1 p4 #aba4 #dj ,comptes rendus1 #ahgi4 ,seance du #bjth ,octobre #ahgi2 ,dingler's polytechniches ,journal1 ,band #bbc1 ,s4 #fjh4 #da ,landolt's ,handbook of the ,polariscope4 p4 #abj4 #db ,sidersky2 ,trait d',analyse des ,matires ,sucres1 p4 #ig4 #dc ,manual of ,sugar ,analysis1 pp4 #adc et seq4 #dd ,landolt und ,brnstein1 ,physikalisch-,chemische ,tabellen4 ,s4 #dfj4 #de ,bulletin ,no4 #ca4 ,department of ,agriculture1 ,division of ,chemistry1 p4 #bcb4 #df ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie4 #ahgj1 ,s4 #bbc4 #dg ,tucker's ,manual of ,sugar ,analysis1 p4 #afd4 #dh 7bis74 ,gerlach1 ,spencer's ,handbook for ,sugar ,manufacturers1 p4 #ia4 #di ,vid4 op4 cit4 supra1 p4 #de4 #ej ,vid4 loc4 et op4 cit4 supra4 #ea ,gill2 ,journal of the ,chemical ,society1 ,vol4 #bd1 #ahga1 p4 #ia4 #eb ,wiley2 ,american ,chemical ,journal1 ,vol4 #f1 p4 #bhi4 #ec ,vid4 op4 cit4 supra1 p4 #cja4 #ed ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahij4 ,s4 #hgf4 #ee ,weber and ,mc,pherson2 ,journal of the ,american ,chemical ,society4 ,vol4 #ag1 p4 #cbj2 ,bulletin ,no4 #dc4 ,department of ,agriculture1 ,division of ,chemistry1 p4 #abf4 #ef ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahhh1 ,s4 #ea4 #eg ,vid4 op4 cit4 supra1 ,ss1 #fii und #gfc2 #ahij4 ,s4 #bag4 #eh ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,may1 #ahij1 p4 #dca4 #ei ,neue ,zeitschrift fr ,rbenzucker-,industrie1 ,band #ai1 ,s4 #ga4 #fj ,journal of the ,chemical ,society1 ,transactions1 ,vol4 #eg1 pp4 #hcd1 et seq4 #fa ,op4 cit4 supra1 p4 #hff4 #fb ,op4 cit4 supra1 #ahia1 p4 #df4 #fc ,neue ,zeitschrift fr ,rbenzucker-,industrie1 ,band #ai1 ,s4 #ga4 #fd ,from and 774 #fe ,landolt's ,handbook of the ,polariscope1 p4 #abe4 #ff ,vid4 op4 cit4 supra1 pp4 #dh et seq4 #fg ,berichte der deutschen chemischen ,gesellschaft1 #ahgg1 ,s4 #adjc4 #fh ,die landwirtschaftlichen ,versuchs-,stationen1 ,band #dj1 ,s4 #cjg4 #fi ,spencer's ,handbook for ,sugar ,manufacturers1 p4 #hj2 ,landolt's ,handbook of the ,polariscope1 p4 #baf2 ,tollens' ,handbuch der ,kohlenhydrate4 #gj ,annalen der ,chemie and ,pharmacie1 ,may1 #ahgj4 #ga ,tucker's ,manual of ,sugar ,analysis1 p4 #bjh4 #gb ,rapport fait a la ,socit d',encouragement d',agriculture2 ,journal de ,pharmacie et de ,chimie1 #ahdd4 #c;d serie1 ,tome #f1 p4 #cja4 #gc ,annalen der ,chemie und ,pharmacie1 ,band #ci1 ,s4 #cfa4 #gd ,jahrbcher fr praktische ,heilkunde1 #ahde1 ,s4 #eji4 #ge ,archives fr ,physiologische ,heilkunde1 #ahdh1 ,band #g1 ,s #fd4 #gf ,rodewald and ,tollens2 ,berichte der deutschen chemischen ,gesellschaft1 ,band #aa1 ,s4 #bjgf4 #gg ,chemical ,news1 ,vol4 #ci1 p4 #gg4 #gh ,the ,analyst1 ,vol4 #ai1 p4 #aha4 #gi ,gaud2 ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,apr4 #ahie1 p4 #fbi2 ,comptes rendus1 #ahid1 ,tome #aai1 p4 #fjd4 #hj ,annalen der ,chemie und ,pharmacie1 ,b4 #gb1 ,s4 #ajf4 #ha ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #d1 p4 #cgj4 #hb ,wiley2 ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,april1 #ahhd4 #hc ,vid4 op4 cit4 supra1 #ahie1 p4 #fdb2 ,comptes rendus1 ,tome #aai1 #ahid1 p4 #fej4 #hd ,annual ,report1 ,united ,states ,department of ,agriculture1 #ahgi1 p4 #fe2 ,zeitschrift fr ,analytische ,chemie1 ,band #ab1 ,s4 #bif2 ,mohr ,titrirmethode1 sechste auflage1 ,s4 #ejh4 #he ,comptes rendus1 #ahid1 ,tome #aai1 p4 #dgh4 #hf ,gazetta ,chimica ,italiana1 ,tome #f1 p4 #cbb4 #hg ,sidersky2 ,trait d',analyse des ,matires ,sucres1 p4 #adh4 #hh ,vid4 op4 cit4 supra1 p4 #adi4 #hi ,neue ,zeitschrift fr die ,rbenzucker-,industrie1 ,band #bb1 ,s4 #bbj4 #ij ,zeitschrift des ,vereins fr ,rbenzucker-,industrie1 #ahhi1 ,s4 #icc4 #ia ,vid4 op4 cit4 supra1 #ahhg1 ,s4 #adg4 #ib ,berichte der deutschen chemischen ,gesellschaft1 ,band #bc1 ,no4 #ad1 ,s4 #cjjc2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahia1 ,s4 #ig4 #ic ,ost2 vid4 op4 et loc4 cit4 supra4 #id ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahij1 ,s4 #ahg4 #ie ,chemical ,news1 ,vol4 #ci1 p4 #gg4 #if ,the ,analyst1 #ahid1 p4 #aha4 #ig ,chemical ,news1 ,vol4 #ga1 p4 #bce4 #ih ,journal de ,pharmacie et de ,chimie1 #ahid1 ,tome #cj1 p4 #cje4 #ii ,pharmaceutical ,journal1 7#c71 #bc1 p4 #bjh4 #ajj ,vid4 op4 cit4 supra1 7#c71 #be1 p4 #iac4 #aja ,sidersky2 ,bulletin de l',association des ,chimistes1 ,juillet1 #ahhf et ,sept4 #ahhh4 #ajb ,bodenbender and ,scheller2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahhg1 ,s4 #ach4 #ajc ,vid4 op4 cit4 supra1 #ahhi1 ,s4 #ice4 #ajd ,ewell2 ,manuscript communication to author4 #aje ,journal fr praktische ,chemie1 #ahhj1 ,band #bb1 #df2 ,handbuch der ,spiritusfabrication1 #ahij1 ,s4 #gi2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahgi1 ,s4 #ajej2 ,ibid1 #ahhc1 ,s4 #gfi2 ,ibid1 #ahhi1 ,s4 #gcd4 #ajf ,handbuch der ,spiritusfabrication1 #ahij1 #gi4 #ajg ,wein2 ,tabellen zur quantitativen ,bestimmung der ,zuckerarten1 ,s4 #ac4 7,the caption for the table on page #aei should read as on page #afj47 #ajh ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahhi1 ,s4 #gce4 #aji ,bulletin ,no4 #dc1 ,department of ,agriculture1 ,division of ,chemistry1 p4 #bji4 #aaj ,chemiker-,zeitung1 #ahic1 ,s4 #edh4 #aaa ,wein2 ,tabellen zur quantitativen ,bestimmung der ,zuckerarten1 ,s4 #ce4 #aab ,berichte der deutschen chemischen ,gesellschaft1 ,band #af1 ,s4 #ffa4 #aac ,vid4 op4 cit4 supra1 ,band #bb1 ,s4 #hg4 #aad ,chemisches ,centralblatt1 #ahie1 ,band #b1 ,s4 #ff4 #aae ,comptes rendus2 ,tome #aab1 ,no4 #ae1 p4 #gii4 #aaf ,vid4 op4 cit4 supra1 ,tome #id1 p4 #aeag4 #aag ,journal of the ,chemical ,society1 ,june1 #ahhh1 p4 #faj4 7,in the formulas for lactose and arabinose read ,h and ,h respectively47 #aah ,american ,chemical ,journal1 ,vol4 #aa1 ,no4 #g1 p4 #dfi4 #aai ,chemisches ,centralblatt1 #ahhi1 ,no4 #g4 #abj ,american ,chemical ,journal1 ,vol4 #ag1 ,no4 #g1 pp4 #ejg1 #eag4 #aba ,comptes rendus1 ,tome #aah1 p4 #dbf4 #abb ,justus ,liebig's ,annalen der ,chemie1 #ahij4 ,band #beg1 ,s4 #afj4 #abc ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #g1 pp4 #fh et seq4 #abd ,flint and ,tollens2 ,berichte der deutschen chemischen ,gesellschaft1 ,band #be1 ,s4 #biab4 #abe ,vid4 op4 cit4 supra1 ,band #bc1 ,s4 #agea4 7,read ,gnther47 #abf ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #e1 p4 #dba4 #abg ,vid4 op4 cit4 supra1 p4 #dbf4 #abh ,berichte der deutschen chemischen ,gesellschaft1 ,band #bd1 ,s4 #cege4 #abi ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #g1 p4 #gd4 #acj ,chemiker-,zeitung1 ,band #ag1 #agdc4 #aca ,vid4 op4 cit4 supra1 ,band #ah1 ,n4 #ea1 ,s4 #iff4 #acb ,monatshefte fr ,chemie1 ,band #af1 ,s4 #bhc2 ,berichte der deutschen chemischen ,gesellschaft1 ,referate ,band #bh1 ,s4 #fbi4 #acc ,papasogli2 ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,juillet #ahie1 p4 #fh4 #acd ,gans und ,tollens2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 ,band #ch1 ,s4 #aabf4 #ace ,berichte der deutschen chemischen ,gesellschaft1 #bj1 ,s4 #aha2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahia1 ,s4 #hie4 #acf ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahia1 ,s4 #hia4 #acg ,chemiker-,zeitung1 #ahhh1 ,no4 #b2 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahhh1 ,s4 #cdg4 #ach ,fischer2 ,berichte der deutschen chemischen ,gesellschaft1 ,band #bj1 ,s4 #hba2 ,band #ba1 ,ss4 #ihh2 #bfca4 #aci ,zeitschrift fr physiologische ,chemie1 ,band #aa1 ,s4 #dib4 #adj ,vid4 op4 cit4 supra1 ,band #ab1 ,no4 #d1 ,ss4 #cee et seq2 ,no4 #e1 ,ss4 #cgg et seq4 #ada ,berichte der deutschen chemischen ,gesellschaft1 ,band #bj1 ,s4 #edj4 #adb ,sitzungsberichte der ,mathematisch-,naturwissenschaften in ,wien1 ,band #ic1 ,heft #b1 ,s4 #iab4 #adc ,tollens2 ,handbuch der ,kohlenhydrate2 von ,lippmann1 ,chemie der ,zuckerarten4 #add ,wilder ,quarter-,century ,book1 #ahic2 ,abdruck aus dem ,centralblatt fr ,bakteriologie und ,parasitenkunde1 ,band #ah1 #ahie1 ,no4 #a2 ,american ,journal of ,medical ,sciences1 ,sept41 #ahie4 #ade ,griffiths1 ,principal ,starches used as ,food2 ,ngeli's ,beitrge zur nheren ,kenntniss der ,strkegruppe4 #adf ,zeitschrift fr ,physiologische ,chemie1 ,band #ab1 ,ss4 #ge-gh4 #adg ,maercker2 ,handbuch der ,spiritusfabrikation1 #ahij1 ,s4 #ij4 #adh ,chemiker-,zeitung1 ,band #ai1 ,s4 #aeja4 #adi ,paragraphs #bh-cb1 this volume4 #aej ,vol4 #b1 p4 #bjd4 #aea ,chemisches ,centralblatt1 #ahgg1 ,band #h1 ,s4 #gcb4 #aeb ,chemiker-,zeitung1 ,band #ai1 ,s4 #aeja4 #aec ,vid4 op4 cit4 supra1 ,s4 #aejb2 ,moniteur ,scientifique1 #ahhg1 p4 #ech4 #aed ,chemiker-,zeitung1 ,band #ai1 ,s4 #aejb4 #aee ,vid4 op4 cit4 supra1 #ahie1 ,s4 #agbg4 #aef ,chemiker-,zeitung1 ,band #ai1 ,s4 #aejb4 #aeg ,jahresberichte der ,agrikulturchemie1 #ahib1 ,s4 #ffd4 #aeh ,journal de ,pharmacie et de ,chimie1 #e1 ,srie1 ,tome #be1 p4 #cid4 #aei ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #fd4 #afj ,repertorium der ,analytischen ,chemie1 #ahhg1 ,s4 #bii4 #afa ,journal of the ,american ,chemical ,society1 ,vol4 #af1 p4 #gbf4 #afb ,frschungs ,berichte ber ,lebensmittel1 ,hamburg2 ,abs41 ,the ,analyst1 ,vol4 #bj1 p4 #baj4 #afc ,rouvier2 ,comptes rendus1 ,tome #ajg1 pp4 #bgb1 #bgh2 ,tome #aaa1 pp4 #fd1 #ahf2 ,tome #abj1 p4 #aagi4 #afd ,bulletin #ac1 ,department of ,agriculture1 ,division of ,chemistry1 pp4 #aed et4 seq4 #afe ,foods1 ,their ,composition and ,analysis1 p4 #aci4 #aff ,richardson1 ,vid4 op4 cit4 #adb1 p4 #aeh4 #afg ,principal ,starches used as ,food1 ,cirencester1 ,baily ,son1 ,market ,place4 #afh ,vid4 op4 cit4 #adb1 pp4 #aeh et seq4 #afi ,bulletin #dd1 ,department of ,agriculture1 ,division of ,chemistry1 p4 #ad4 ,,part ,,third4 ,,processes ,,for ,,detecting ,,and ,,determining ,,sugars ,,and ,,starches ,,and ,,other ,,carbohydrates ,,in ,,crude ,,or ,,manufactured ,,agricultural ,,products4 #bjc4 ,introduction4--,in the preceding part directions have been given for the estimation of sugars and starches in approximately pure forms4 ,in the present part will be described the most approved methods of separating these bodies and other carbohydrates from crude agricultural products and for their chemical examination4 ,in many respects the processes which in a small way are used for preparing samples for analysis are employed on a large scale for technical and manufacturing purposes4 ,it is evident1 however1 that the following paragraphs must be confined strictly to the analytical side of the question inasmuch as anything more than mere references to technical processes would lead into wide digressions4 ,in the case of sugars the analyst is for the most part quite as much in need of reliable methods of extraction and preparation as of processes for analysis4 ,with starches the matter is more simple and the chief methods of separating them for examination were necessarily described in the previous part4 ,sugars in fresh plants exist almost entirely in solution4 ,this is true of all the great sources of the sugar of commerce1 viz41 the palm1 the maple1 the sugar beet and sugar cane4 ,this statement is also true of fruits and the natural nectar of flowers4 ,by natural or artificial drying the sugar may be reduced to the solid or semisolid state as in the cases of raisins and honey4 ,in certain seeds1 deficient in water1 sugars may possibly exist in a solid state naturally1 as may be the case with sucrose in the peanut and raffinose in cotton seed4 ,starches on the other hand when soluble1 are probably not true starches1 but they partake more or less of a dextrinoid nature4 ,fine starch particles occur abundantly in the juices of some plants1 as for instance sorghum1 where they are associated with sugar and can be obtained from the expressed juice by subsidence4 ,but even in such a case it is not certain that the starch enters into the general circulation4 ,it is more likely formed locally by biochemical condensation of its constituents4 ,starches in a soluble or semisoluble state are transported1 as a rule1 to the tubers or seeds of plants where they are accumulated in large quantities as a reserve food for future growth4 ,for a study of the plant metabolism whereby starch is produced and for its histological and physiological properties the reader may consult the standard authorities on vegetable physiology4#agj #bjd4 ,sugar in the ,sap of ,trees4--,many trees at certain seasons of the year1 carry large quantities of sugar in their sap4 ,among these the maple and sugar palm are preeminent4 ,the sap is secured by cutting a pocket into the side of the tree or by boring into it and allowing the sap to run into an appropriate receptacle through a spile4 ,the content of sugar in the sap of the maple and palm varies greatly4 ,in some cases it falls as low as one and a half and in others rises to as much as six or seven per cent4#aga ,in most cases the sugar in the maple sap is pure sucrose1 but towards the end of the flowing season it may undergo changes of a viscous nature due to fermentation1 or inversion1 forming traces of invert sugar4 ,in this country the sap of the maple may flow freely on any warm day in winter1 but the sugar season proper begins about ,february #aeth in ,southern ,ohio and ,indiana1 and about ,march #beth in ,vermont4 ,it lasts from six weeks to two months4 ,the sap flows best during moderately warm1 still days1 after a light freeze4 ,in addition to sugar the maple sap contains a trace of albuminoid matters and some malic acid combined with lime4 ,as a rule it can be subjected to polarization without preliminary clarification4 #bje4 ,determination of ,sugar in ,saps4--,in most cases the sap may be directly polarized in a #bjj millimeter tube4 ,its specific gravity is obtained by a spindle or pyknometer1 and the percentage of sugars taken directly from the table on page #gc1 the degree brix corresponding to the sugar percentage4 ,on polarizing1 the sugar percentage is calculated as follows3 ,multiply the specific gravity of the sap by #ajj and divide the product by #bf4jdh4 ,divide the direct reading of the sap on the sugar scale by the quotient obtained above1 and the quotient thus obtained will be the correct percentage of sugar in the original solution4 ,the formula is applicable for those instruments in which #bf4jdh grams represent the normal quantity of sugar which in #ajj cubic centimeters reads #ajj divisions on the scale4 ,when other factors are used they should be substituted for #bf4jdh in the above formula4 ,the principle of the calculation is based on the weight of the sap which is contained in #ajj cubic centimeters1 and this is evidently obtained by multiplying #ajj by the specific gravity of the sap4 ,since #bf4jdh is the normal quantity of sugar in that volume of the solution the quotient of the actual weight divided by that factor shows how many times too great the observed polarization is4 ,the simple division of the polariscope reading by this factor gives the correct reading4 ,example3 ,let the specific gravity of the sap be #a4jae and the observed polarization be #ae4j4 ,then the true percentage of sugar in the sap is found by the equation3 #aja4e 3 #bf4jdh #ae4j 3 x4 ,whence x #c4he percentage of sugar in the sap4 ,the process outlined above is not applicable when a clarifying reagent such as lead subacetate or alumina cream must be used4 ,but even in these cases it will not be found necessary to weigh the sap4 ,a sugar flask graduated at #ajj and #aaj cubic centimeters is used and filled to the first mark with the sap1 the specific gravity of which is known4 ,the clarifying reagent is added1 the volume completed to the second mark with water1 and the contents of the flask well shaken and thrown on a dry filter4 ,the observation tube1 which should be #bbj millimeters in length1 is then filled with the clear filtrate and the rest of the process is as described above4 ,a #bjj millimeter tube may also be used in this case and the observed reading increased by one-tenth4 ,illustration3 ,,fig4 #fb4 ,,laboratory ,,cane ,,mill4 ,illustration3 ,,fig4 #fc4 ,,weighing ,,pipette4 #bjf4 ,estimation of ,sugar in the ,sap of ,sugar ,cane and ,sorghum4--,in bodies like sugar cane and sorghum the sap containing the sugar will not flow as in the cases of the maple and sugar palm4 ,the simplest way of securing the sap of the bodies named is to subject them to pressure between rolls4 ,a convenient method of obtaining the sap or juice is by passing the cane through a small three-roll mill indicated in the figure4 ,small mills of this kind have been used in this division for many years and with entire satisfaction4 ,small canes1 such as sorghum1 may be milled one at a time1 or even two or three when they are very small4 ,in the case of large canes1 it is necessary that they be split and only half of them used at once4 ,the mill should not be crowded by the feed in such a way as to endanger it or make it too difficult for the laborer to turn4 ,from fifty to sixty per cent of the weight of a cane in juice may be obtained by passing it through one of these small mills4 ,experience has shown that there is a little difference between the juice as first expressed and the residual sap remaining in the bagasse1 but the juice first expressed may be used for analysis for control purposes as a fair representative of all that the cane contains4 ,to determine the percentage of juice expressed1 the canes may be weighed before passing through the mill and the juice collected4 ,its weight divided by the weight of the original cane will give the per cent of the juice expressed1 calculated on the whole cane4 ,instead of weighing the juice the bagasse may also be collected and weighed2 but on account of the rapidity with which it dries the operation should be accomplished without delay4 ,the expressed juice is clarified with lead subacetate1 filtered and polarized in the manner described in former paragraphs4 ,instead of weighing the juice1 its specific gravity may be taken by an accurate spindle and the volume of it1 equivalent to a given weight1 measured from a sucrose pipette4#agb ,a sucrose pipette for cane juice has a graduation on the upper part of the stem which enables the operator to deliver double the normal weight for the polariscope used1 after having determined the density of the juice by means of a spindle4 ,a graduation of from #e to #be of the brix spindle will be sufficient for all variations in the density of the juice1 or one covering a range of from #aj to #bj will suffice for most instances4 ,the greater the density of the juice the less volume of it will be required for the weight mentioned4 ,for general use1 the sucrose pipette is graduated on the stem to deliver from forty-eight to #ej4e cubic centimeters1 the graduations being in terms of the brix spindle4 ,the graduation of the stem of this instrument is shown in the accompanying figure4 ,in the use of the pipette it is only necessary to fill it to the degree on the stem corresponding to the degree brix found in the preliminary trial4 ,the quantities of juice corresponding to each degree and fractional degree of the brix spindle are given in the following table2 calculated for the normal weight #bf4jdh grams for the ventzke and for #af4ai grams for the laurent scale4 ,the measured quantities of juice are placed in a #ajj cubic centimeter sugar flask1 treated with the proper quantity of lead subacetate1 the volume completed to the mark1 and the juice filtered and polarized in a #bjj millimeter tube4 ,the reading of the polariscope is divided by two for the factor #bf4jdh and by three for the factor #af4ai4 ,,table ,,for ,,use ,,of ,,sucrose ,,pipettes4 ,cubic centimeters ,cubic centimeters of juice for #bf4jdh of juice for #af4ai ,degrees factor4 ,divide ,degrees factor4 ,divide brix4 reading by two4 brix4 reading by three4 #e4j #ea4a #e4j #dg4f #e4d #ea4j #e4g #dg4e #e4g #ej4i #f4c #dg4d #f4d #ej4h #f4h #dg4c #f4i #ej4g #g4c #dg4b #g4d #ej4f #g4h #dg4a #g4i #ej4e #h4c #dg4j #h4d #ej4d #h4i #df4i #h4i #ej4c #i4e #df4h #i4d #ej4b #aj4j #df4g #i4i #ej4a #aj4e #df4f #aj4d #ej4j #aa4j #df4e #aj4i #di4i #aa4f #df4d #aa4d #di4h #ab4a #df4c #aa4i #di4g #ab4g #df4b #ab4d #di4f #ac4c #df4a #ab4i #di4e #ac4h #df4j #ac4d #di4d #ad4c #de4i #ac4i #di4c #ad4h #de4h #ad4d #di4b #ae4c #de4g #ad4i #di4a #ae4i #de4f #ae4d #di4j #af4d #de4e #ae4i #dh4i #ag4j #de4d #af4d #dh4h #ag4e #de4c #af4i #dh4g #ah4j #de4b #ag4d #dh4f #ah4f #de4a #ag4i #dh4e #ai4a #de4j #ah4d #dh4d #ai4g #dd4i #ah4i #dh4c #bj4b #dd4h #ai4d #dh4b #ai4i #dh4a ,in ordering sucrose pipettes the factor for which they are to be graduated should be stated4 ,it is evident also that with the help of the foregoing table the measurements may be made by means of a burette4 ,for instance1 if the degree brix is found to be #ai4i1 #dh4a cubic centimeters are to be used4 ,this quantity can be easily run from a burette4 ,in order to make the pipette more convenient it has been customary in this laboratory1 as practiced by ,carr1 to attach a glass tube with a stopcock by means of a rubber tube to the upper part of the pipette1 whereby the exact level of the juice in the stem of the pipette can be easily set at any required mark4 ,in the polarization of dilute solutions1 such as are found in the saps and juices referred to above1 it must not be forgotten that the gyrodynat of the sucrose is increased as the density of the solution is diminished4 ,this change introduces a slight error into the work which is of no consequence from a technical point of view1 but becomes a matter which must be considered in exact determinations4 ,to avoid the annoyance of calculating the gyrodynat for every degree of concentration1 tables have been constructed by ,schmitz and ,crampton by means of which the actual percentage of sugar1 corresponding to any degree of polarization1 is determined by inspection4 ,these tables may be used when extremely accurate work is required4#agc ,illustration3 ,,figure #fd4 ,,gird',s ,,gravimeter4 #bjg4 ,measuring ,sugar ,juices with a ,gravimeter4--,a convenient method of weighing sugar juices is the gravimetric process designed by ,gird4#agd ,the apparatus is fully illustrated by ,fig4 #fd4 ,the hydrometer ,f has a weight of #bf4jdh grams and its stem is also graduated in degrees brix4 ,the juice is poured into the cylinder ,a and allowed to stand until air bubbles have escaped4 ,in filling ,a the finger is held over the orifice ,g so that the siphon tube ,b is completely filled1 the air escaping at the vent ,c4 ,after the tube is filled the finger is withdrawn from ,g and all the liquid which will run out at ,g allowed to escape4 ,the sugar flask ,d is now brought under ,g and the hydrometer ,f allowed to descend into ,a4 ,the hydrometer will displace exactly its own weight of liquid4 ,for convenience of reading1 the index ,e may be used which is set five degrees above the surface of the liquid in ,a4 ,the number of degrees brix read by ,e is then diminished by five4 ,the hydrometer has been improved since the description given by the addition of a thermometer which1 in addition to carrying a graduation in degrees1 also shows the correction to be made upon the degree brix for each degree read4 ,it is evident that the hydrometer may be made of any weight1 and thus the delivery of any desired amount of juice be secured4 #bjh4 ,determination of ,reducing ,bodies in ,cane ,juices4--,sucrose in cane juices is constantly accompanied with reducing sugars1 or other bodies which have a similar action on fehling liquor1 which interfere to a considerable degree with the practical manufacture of sugar4 ,it is important to determine with a moderate degree of accuracy the quantity of these bodies4 ,these sugars or reducing bodies are of a peculiar nature4 ,the author pointed out many years ago that these reducing bodies were without action on polarized light1 and for this reason proposed the name anoptose as one characteristic of their nature4#age ,it is also found that these bodies do not yield theoretically the quantity of alcohol which a true sugar of the hexose type would give4#agf ,it is entirely probable1 therefore1 that they are quite different in their nature from many of the commonly known sugars4 ,on account of the difficulty of separating these bodies in a pure state their actual copper reducing power is not known4 ,for practical purposes1 however1 it is assumed to be the same as that of dextrose or invert sugar and the percentage of these bodies present is calculated on that assumption4 ,in the determination of these sugars or reducing bodies1 the quantity weighed may be determined by an apparatus entirely similar to the sucrose pipette just described above4 ,the quantity of juice used should be diluted as a rule to such a degree as not to contain more than one per cent of the reducing bodies4 ,for the best work1 the juices should be clarified with lead subacetate and the excess of lead removed with sodium carbonate4 ,for technical control work in sugar factories1 this process may be omitted as in such cases rapidity of work is a matter of considerable importance and the approximate estimation of the total quantity of reducing bodies is all that is desired4 ,for volumetric work1 the solution of copper and the method of manipulation described in paragraph #aag are most conveniently used4 #bji4 ,preservation of ,sugar ,juices for ,analysis4--,lead subacetate not only clarifies the juices of canes and thus permits of their more exact analytical examination1 but also exercises preservative effects which enable it to be used as a preserving agent and thus greatly diminish the amount of work necessary in the technical control of a sugar factory4 ,instead1 therefore1 of the analyst being compelled to make an examination of every sample of the juice1 aliquot portions representing the different quantities can be preserved and one analysis made for all4 ,this method has been thoroughly investigated by ,edson1 who also finds that the errors1 which may be introduced by the use of the lead subacetate in the analytical work1 may be entirely avoided by using the normal lead acetate4#agg ,in the use of the normal lead acetate1 much less acetic acid is required in the polariscopic work than when the subacetate is used4 ,the normal lead acetate is not so good a clarifying agent as the subacetate1 but its efficiency in this respect is increased by the addition of a little acetic acid4 ,in its use1 it is not necessary to remove the lead1 even for the determination of the reducing bodies4 ,for further details in regard to the technical determination of reducing bodies1 special works may be consulted4#agh #baj4 ,direct ,determination of ,sugars in ,canes4--,the methods1 which have just been described1 of securing the juices of cane by pressure and of determining the sugars therein1 do not give the actual percentage of sugar in the cane4 ,an approximate result may be secured by assuming that the cane is composed of ninety parts of juice and ten parts of cellular tissues and other insoluble matters4 ,this assumption is approximately true in most cases1 but there are often conditions arising which render the data calculated on the above assumption misleading4 ,in any particular case in order to be certain that the correct percentage of sugar is secured it will be necessary to determine the fiber in the cane4 ,this is an analytical process of considerable labor and especially so on account of the difficulty of securing samples which represent the average composition of the cane4 ,the fibrous structure of the canes1 the hardness of their external covering and the toughness of their nodes or joints render the sampling extremely difficult4 ,moreover1 the content of sugar varies in different parts of the cane4 ,the parts nearest the ground are1 as a rule1 richer than the upper joints and this is especially true of sugar cane4 ,in order1 therefore1 to get a fair sample1 even of a single cane1 all parts of it must be considered4 ,several methods of the direct determination of sugar in canes have been proposed and will be described below4 ,illustration3 ,,figure #fe4 ,,machine ,,for ,,cutting ,,canes4 #baa4 ,methods of ,cutting or ,shredding the ,cane for ,analytical ,purposes4--,a simple method of cutting canes into small pieces which will permit of an even sampling is very much to be desired4 ,the cutting apparatus shown in ,fig4 #fe has been long in use in this laboratory4 ,the canes by it are cut into thin slices1 but the cutting edge of the knife being perpendicular to the length of the cane renders the use of the instrument somewhat laborious and unsatisfactory4 ,a considerable time is required to cut a single cane and the slices which are formed should be received in a vessel which will protect them as much as possible from evaporation during the process of the work4 ,instead of the apparatus above a small cane cutting machine arranged with four knives on a revolving disk maybe used4 ,the apparatus is shown in ,fig4 #ff4 ,the cane is fed against the knives through the hole shown in the open front of the apparatus and the knives thus strike the cane obliquely4#agi ,the knives can be set in the revolving disk at any desired position so as to cut the canes into chips as fine as may be desired4 ,the cossettes furnished by this method may be sampled directly for the extraction of the sugar4 ,in the case of the cossettes from both instruments described above a finer subdivision may be secured by passing them through a sausage cutter4 ,illustration3 ,,figure #ff4 ,,cane ,,cutting ,,mill4 ,the best method for shredding canes1 however1 is to pass them through the apparatus described on page #i4 ,that machine gives an extremely fine1 moist mass1 which is of uniform nature and capable of being directly sampled4 #bab4 ,methods of ,determination4--,even the finely divided material obtained by the machine just described is not suited to give an instantaneous diffusion for polarization as is done by the finely ground beet pulp to be described further on4 ,for the determination of sugar a proper weight of the cossettes or pulp obtained as described above1 taken after thorough mixing1 is placed in a flask graduated properly and treated with water4#ahj ,the flask in which the mixture takes place should be marked to compensate for the volume of the fiber of the cane4 ,when the normal weight of cane is taken for the ventzke scale1 viz41 #bf4jdh1 the flask should be graduated at #ajb4f cubic centimeters4 ,if double the normal weight be taken1 the flask should be graduated at #bje4b cubic centimeters4 ,this graduation is based on the assumption of the presence of fiber amounting to ten per cent of the weight of the cossettes4 ,the fiber is so nearly the density of the juice obtained as to be regarded as one gram equal to one cubic centimeter4 ,the flask is at first filled almost full of water and then warmed to near the boiling point for an hour with frequent shaking4 ,it is then filled to a little above the mark1 the contents well mixed and warmed for ten minutes more with frequent shaking4 ,after cooling1 the volume is made up to the mark1 well shaken and poured upon a filter4 ,the filtrate is collected in a sugar flask marked at fifty and fifty-five cubic centimeters4 ,when filled to the first mark a proper quantity of lead subacetate is added1 the volume completed to the second mark with water1 the contents of the flask well shaken1 poured upon a filter and the filtrate polarized in the usual way4 ,the reducing sugar is determined in an aliquot part of the filtrate by one of the alkaline copper methods4 #bac4 ,determination by ,drying and ,extraction4--,instead of the diffusion and polarization method just described1 the fine pulp obtained may be dried1 the dried residue ground in a drug mill and extracted with aqueous alcohol or with water4 ,to facilitate the calculation when this method is employed1 the water content of a small portion of the well sampled pulp is determined4 ,the rest of the pulp is dried1 first for a few hours at a temperature not above #fj or #gj1 and then at the temperature of boiling water1 either in the open air or a partial vacuum1 until all the water is driven off4 ,the dried residue can then be preserved in well stoppered bottles for the determination of sugar at any convenient period4 ,the finely ground dried residue for this purpose is placed in an extraction apparatus and thoroughly exhausted with eighty per cent alcohol4 ,the extract is dried and weighed1 giving the total weight of all sugars present4 ,after weighing1 the extract is dissolved in water1 made up to a definite volume and the reducing sugars determined in an aliquot portion thereof by the usual methods4 ,the weight of reducing sugars found1 calculated for the whole extract deducted from the total weight of this extract will give the weight of the sucrose in the sample4 ,from this number the content of sugar in the original cane is determined from the percentage of water found in the original sample4 ,example4--,in a sample of finely pulped canes the content of water is found to be #gf4e per cent4 ,the thoroughly dried pulp is ground and extracted with aqueous alcohol4 ,five grams give two and five-tenths grams of the extract4 ,the extract is dissolved in water1 made up to a definite volume and the reducing sugars determined in an aliquot part and calculated for the whole1 amounting to #aej milligrams4 ,the extract is therefore composed of #b4ce grams of sucrose and #j4ae gram of reducing sugars4 ,the calculation is now made to the original sample which contained #gf4e per cent of water and #bc4e per cent of dry matter1 as follows3 #e 3 x 33 #bc4e 3 #ajj1 whence x #ba4bg1 the weight of the original material corresponding to five grams of the dry substance4 ,the original composition of the sample is therefore expressed by the following numbers3 ,per cent4 ,sucrose #aa4a ,reducing sugars #j4g ,water #gf4e ,fiber 7insoluble matter7 #aa4g #bad4 ,examination of the ,bagasse4--,the method just described for the examination of canes may be also applied to the analysis of bagasses1 with the changes made necessary by the increased percentage of fiber therein4 ,on account of the large surface exposed by the bagasse1 the sampling1 shredding and weighing should be accomplished as speedily as possible to avoid loss of moisture4 ,the optical examination of bagasses is rendered difficult by reason of the uneven pressure to which the canes are subjected4 ,with fairly good milling in technical work the bagasses will have at least thirty per cent of fiber4 ,the method for the polariscopic examination is therefore based upon that assumption1 but the volume of the solution must be changed for varying percentages of fiber in the bagasse4 ,on account of the smaller percentage of sugar1 it is convenient to take double or three times the normal weight of the bagasse for examination4 ,since large sugar flasks are not commonly to be had the diffusion of the bagasse may be conducted in a quarter liter flask4 ,in a quarter liter flask place #eb4jif grams of the finely shredded bagasse1 very nearly fill the flask with water and extract the sugar as described for canes in the foregoing paragraphs4 ,in the weight of bagasse used there will be1 in round numbers1 fifteen grams of fiber4 ,when the volume of water is completed to the mark the actual content of liquid in the flask will therefore be only #bce cubic centimeters4 ,fifty cubic centimeters of the filtrate are placed in a sugar flask marked at fifty and fifty-five cubic centimeters1 the proper quantity of lead subacetate solution added1 the volume completed to the upper mark1 the contents of the flask well shaken1 filtered and polarized in a #bjj millimeter tube4 ,let the reading obtained be four degrees and increase this by one-tenth for the increased volume of solution above fifty cubic centimeters4 ,the true reading is therefore four degrees and four-tenths4 ,this reading1 however1 must be corrected1 because the original volume instead of being #bjj cubic centimeters1 is #bce cubic centimeters4 ,the actual percentage of sugar in the sample examined is obtained by the following proportion3 #bjj 3 #bce #d4d 3 x4 ,the correct reading is therefore #e4b1 the percentage of sugar in the sample examined4 ,the results obtained by the method just described may vary somewhat from the true percentage by reason of the variation of the content of fiber in the bagasse4 ,it is1 however1 sufficiently accurate for technical control in sugar factories and on account of its rapidity of execution is to be preferred for this purpose4 ,more accurate results would be obtained by drying the bagasse1 and proceeding with the examination in a manner entirely analogous to that described for the extraction of sugar from dried canes by aqueous alcohol4 ,in both instances the reducing sugar is determined in the manner already mentioned4 #bae4 ,determination of ,fiber in ,cane4--,in estimating the content of sugar in canes by the analysis of the expressed juices1 it is important to make frequent determinations of the fiber for the purpose of obtaining correct data for calculation4 ,in periods of excessive drought1 or when the canes are quite mature1 the relative content of fiber is increased1 while1 on the other hand1 in case of immature canes1 or during excessive rainfalls1 it is diminished4 ,the chief difficulty in determining the content of fiber in canes is found in securing a representative sample4 ,on account of the hard and fibrous nature of the envelope and of their nodular tissues1 canes are reduced to a fine pulp with great difficulty by the apparatus in ordinary use4 ,a fairly homogeneous pulp1 however1 may be obtained by means of the shredder described on page #i4 ,the canes having been shredded as finely as possible1 a weighed quantity is placed in any convenient extraction apparatus and thoroughly exhausted with hot water4 ,the treatment with hot water should be continued until a few drops of the extract evaporated on a watch glass will leave no sensible residue4 ,the residual fiber is dried to constant weight at the temperature of boiling water1 cooled in a desiccator and rapidly weighed and the percentage of fiber calculated from the data obtained4 ,on account of the great difficulty of securing a homogeneous pulp1 even with the best shredding machines1 the determination should be made in duplicate or triplicate and the mean of the results entered as the percentage of fiber4 ,the term fiber as used in this sense1 must not be confounded with the same term employed in the analysis of fodders and feeding stuffs4 ,in the latter case the term is applied to the residue left after the successive treatment of the material with boiling1 dilute acid and alkali4 ,the analysis of canes for feeding purposes is conducted in the general manner hereinafter described for fodders4 #baf4 ,estimation of ,sugar in ,sugar ,beets4--,the methods employed for the determination of the sugar content of beets are analogous to those used for canes1 with such variations in the method of extraction as are made possible and necessary by the difference in the nature of these sacchariferous plants4 ,the sugar beet is more free of fiber and the hard and knotty substances composing the joints of plants are entirely absent from their composition4 ,for this reason they are readily reduced to a fine pulp1 from which the sugar is easily extracted4 ,the analytical processes are also greatly simplified by the complete absence of reducing sugars from the juices of healthy beets4 ,the only sugar aside from sucrose which is present in these juices is raffinose1 and this is not found in healthy beets1 except when they have been injured by frost or long keeping4 ,in practical work1 therefore1 the determination of sucrose completes the analysis in so far as sugars are concerned4 ,four methods of procedure will illustrate all the principles of the various processes employed4 #bag4 ,estimation of ,sucrose in the ,expressed ,juice4--,in the first method the beets are reduced by any good shredding machine1 to a fine pulp1 which is placed in a press and the juice expressed4 ,in this liquor1 after clarification with lead subacetate1 the sucrose is determined by the polariscope4 ,the methods of measuring1 clarifying and polarizing are the same as those described for saccharine juices in paragraphs #hc-he4 ,the mean percentage of juice in the sugar beet is ninety-five4 ,the corrected polariscopic reading obtained multiplied by #j4ie will give the percentage of sugar in the beet4 ,example4--,the solids in a sample of beet juice1 as measured by a brix spindle1 are #ag4e per cent4 ,double the normal weight of the juice is measured from a sucrose pipette1 placed in a sugar flask1 clarified1 the volume completed to #ajj cubic centimeters1 the contents of the flask well shaken and filtered4 ,the polariscopic reading obtained is #bi4j4 ,then 7#bi4j #b7 #j4ie #ac4h percentage of sucrose in the beet4 #bah4 ,instantaneous ,diffusion4--,in the second process employed for determining the sugar content of beets1 the principle involved depends on the use of a pulp so finely divided as to permit of the almost instant diffusion of the sugar present throughout the added liquid4 ,this diffusion takes place even in the cold and the process thus presents a convenient and rapid method for the accurate determination of the percentage of sugar in beets4 ,the pulping is accomplished by means of the machine described on page #aj1 or the one shown in ,fig4 #fg4 ,the beet is pressed against the rapidly revolving rasp by means of the grooved movable block and the finely divided pulp is received in the box below4 ,these machines afford a pulp which is impalpable and which readily permits an almost instantaneous diffusion of its sugar content4 ,illustration3 ,,fig4 #fg4 ,,apparatus ,,for ,,pulping ,,beets4 #bai4 ,pellet's ,method of ,cold ,diffusion4--,the impalpable pulp having been obtained1 by one of the processes described1 the content of sugar therein is determined as follows3#aha ,a normal or double normal quantity of the pulp is quickly weighed1 to avoid evaporation1 in a sugar dish with an appropriate lip1 and washed into the flask1 which should be graduated1 as shown in ,fig4 #fh1 to allow for the volume of the fiber or marc of the beet4 ,since the beet pulp contains1 on an average1 four per cent of marc1 the volume which is occupied thereby is assumed to be a little more than one cubic centimeter4 ,since it is advisable to have as large a volume of water as convenient1 it is the practice of ,pellet to wash the pulp into a flask graduated at #bja4ce cubic centimeters4 ,if a #bjj cubic centimeter flask be used1 the weight of the pulp should be #be4hg instead of #bf4jdh grams4 ,after the pulp is washed into the flask1 about six cubic centimeters of lead subacetate of #cj baum are added1 together with a little ether1 to remove the foam4 ,the flask is now gently shaken and water added to the mark and the contents thoroughly shaken4 ,if the pulp is practically perfect1 the filtration and polarization may follow immediately4 ,the filter into which the contents of the flask are poured should be large enough to hold the whole quantity4 ,it is recommended to add a drop or two of strong acetic acid just before completing the volume of the liquid in the flask to the mark4 ,the polarization should be made in a #djj millimeter tube1 which will give directly the percentage of sugar present4 ,it is not necessary to heat the solution in order to insure complete diffusion1 but the temperature at which the operation is conducted should be the ordinary one of the laboratory4 ,in case the pulp is not as fine as should be1 the flask should be allowed to stand for half an hour after filling1 before filtration4 ,an insufficient amount of lead subacetate may permit some rotatory bodies other than sugar to pass into solution1 and care should be taken to have always the proper quantity of clarifying material added4 ,the presence of these rotating bodies1 mostly of a pectic nature1 may be shown by extracting the pulp first with cold water until all the sugar is removed1 and afterwards with boiling water4 ,the liquor obtained from the last precipitation will show a decided right-handed rotation1 unless first treated with lead subacetate1 in which case the polarization will be zero4 ,a very extended experience with the instantaneous cold aqueous diffusion has shown that the results obtained thereby are quite as reliable as those given by hot alcoholic or aqueous digestion4 #bbj4 ,flask for ,cold ,diffusion and ,alcohol ,digestion4--,for convenience in washing the pulp into the sugar flask1 the latter is made with an enlarged mouth as shown in ,fig4 #fh4 ,the dish holding the weighed quantity of pulp is held with the lip in the mouth of the flask1 and the pulp washed in by means of a jet of water furnished from a pressure bottle or washing flask4 ,the flask shown is graduated for the normal weight of pulp1 viz41 #bf4jdh grams4 ,the marking is on the constricted neck and extends from #ajj to #aja4c cubic centimeters4 ,this permits of making the proper allowance for the volume occupied by the marc or fiber1 but this is unnecessary for the usual character of control analyses4 ,in the case of healthy1 fresh beets1 the volume occupied by the marc is nearly one and three-tenths cubic centimeters for the normal polariscopic weight of #bf4jdh grams of pulp4 ,for the laurent instrument this volume is nearly one cubic centimeter4 ,illustration3 ,,figure #fh4 ,,apparatus ,,for ,,cold ,,diffusion4 #bba4 ,extraction with ,alcohol4--,the third method of determining sugar in beets is by alcoholic extraction4 ,the principle of the method is based on the fact that aqueous alcohol of not more than eighty per cent strength will extract all the sugar from the pulp1 but will not dissolve the pectic and other rotatory bodies1 which1 in solution1 are capable of disturbing the rotatory power of the sugar present4 ,it is also further to be observed that the rotatory power of pure sucrose1 in an aqueous alcoholic solution1 is not sensibly different from that which is observed in a purely aqueous liquid4 ,the pulp1 which is to be extracted1 should be in as fine a state of subdivision as convenient1 and the process may be carried on in any of the forms of extraction apparatus already described1 or in the apparatus shown in ,fig4 #fi4 ,the extraction tube1 of the ordinary forms of apparatus1 however1 is scarcely large enough to hold the required amount of pulp1 and therefore special tubes and forms of apparatus have been devised for this method of procedure4 ,in weighing the pulp for extraction1 a quarter1 half1 or the exact amount required for the polariscope employed1 should be used4 ,if the tubes are of sufficient size the full weight may be taken1 viz41 #bf4jdh or #af4ai grams for the instruments in ordinary use4 ,since the pulp contains a large quantity of water1 the extraction could be commenced with alcohol of standard strength1 viz41 about ninety-five per cent4 ,the volume of alcohol employed should be such as will secure a strength of from seventy to eighty per cent when mixed with the water contained in the pulp4 ,the flask receiving the extract should be kept in continuous ebullition and the process may be regarded as complete in about one hour1 when the pulp has been properly prepared4 ,the method of extracting beet pulp with alcohol is due to ,scheibler1 and in its present form the process is conducted according to the methods described by ,scheibler1 ,sickel1 and ,soxhlet4#ahb ,illustration3 ,,fig4 #fi4 ,,sickel-,,soxhlet ,,extractor4 ,if the pulp be obtained by any other means than that of a fine rasp1 the extraction of the sugar by the aqueous alcohol takes a long time1 and even a second extraction may be necessary4 ,it is convenient to use as a flask for holding the solvent1 one already graduated at #ajj or #aaj cubic centimeters4 ,a flask especially constructed for this purpose1 has a constricted neck on which the graduations are made1 and a wide mouth serving to attach it to the extracting apparatus1 as shown in ,fig4 #fh4 ,when the extract is obtained in this way1 it is not necessary to transfer it to a new flask before preparing it for polarization4 ,when the extraction is complete1 the source of heat is removed1 and when all the alcohol is collected in the flask1 the latter is removed from the extraction apparatus1 cooled to room temperature1 a sufficient quantity of lead subacetate added1 the flask well shaken1 the volume completed to the mark with water1 again well shaken and the contents of the flask thrown upon the filter4 ,it is important to avoid loss of alcohol during filtration4 ,for this purpose it is best to have a folded filter and to cover the funnel immediately after pouring the contents of the flask upon the filter paper1 with a second larger funnel4 ,the stem of the funnel carrying the filter paper1 should dip well into the flask receiving the filtrate4 ,as in other cases of filtering sugar juices for polarization1 the first portions of the filtrate received should be rejected4 ,the percentage of sugar is obtained in the filtrate in the usual way4 ,where a weight of pulp equal to the normal factor of the polariscope employed is used1 and the extract collected in a #ajj cubic centimeter flask1 the percentage of sugar is directly obtained by making the reading in a #bjj millimeter tube4 ,with other weights of pulp1 or other sizes of flask1 the length of the observation tube may be changed or the reading obtained corrected by multiplication or division by an appropriate factor4 ,a battery of sickel-soxhlet extractors is shown in ,fig4 #fi4ahc ,illustration3 ,,fig4 #gj4 #bbb4 ,scheibler's ,extraction ,tube4--,in order to secure a speedy extraction of large quantities of pulp1 ,scheibler recommends the use of the extraction tube shown in ,fig4 #gj4ahd ,the apparatus is composed of three concentric glass cylinders4 ,the outer and middle cylinders are sealed together at the top1 and the inner one is movable and carries a perforated diaphragm below1 for filtering purposes4 ,near the top it is provided with small circular openings1 whereby the alcoholic vapors may gain access to the condenser 7not shown74 ,the middle cylinder is provided with two series of apertures1 through the higher of which the vapor of alcohol passes to the condenser1 while the alcohol which has passed through the pulp and collected between the inner and middle cylinders1 flows back through the lower into the flask 7not shown7 containing the boiling alcohol4 ,the middle cylinder is provided with a curved bottom to prevent the filtering end of the inner tube from resting too tightly against it4 ,the tube containing the pulp is thus protected from the direct heat of the alcoholic vapors during the progress of extraction by a thin cushion of liquid alcohol4 #bbc4 ,alcoholic ,digestion4--,the fourth method of determining sugar in beet pulp1 is by means of digestion with hot alcohol4 ,the principle of this method is precisely the same as that which is involved in aqueous diffusion in the cold4 ,the diffusion1 however1 in the case of the alcohol1 is not instantaneous1 but is secured by maintaining the mixture of the pulp and alcohol for some time at or near the boiling point4 ,the methods of preparing the pulp1 weighing it and introducing it into the digestion flask are precisely those used for aqueous digestion1 but in the present case a somewhat coarser pulp may be employed4 ,the method is commonly known as the rapp-degener process4#ahe ,any convenient method of heating the alcohol may be used4 ,in this laboratory the flasks are held on a false bottom in a bath composed of two parts of glycerol and one of water4 ,one side of the bath holder is made of glass1 as shown in ,fig4 #ga1 in order to keep the flasks in view4 ,in order to avoid the loss of alcohol1 the digestion flask should be provided with a reflux condenser1 or be attached to an ordinary condenser1 which will reduce the vapors of alcohol again to a liquid4 ,unless the weather be very warm1 the reflux condenser may consist of a glass tube of rather wide bore and at least one meter in length1 as shown in ,fig4 #ga4 ,a slight loss of alcohol during the digestion is of little consequence4 ,a convenient method of procedure is the following4 ,double the quantity of the beet pulp required for the ventzke polariscope1 viz41 #eb4jif grams1 weighed in a lipped metal dish1 is washed1 by means of alcohol1 into a flask marked at #bjb4f cubic centimeters1 and the flask filled two-thirds with ninety-five per cent alcohol and well shaken4 ,afterwards1 a proper quantity of lead subacetate is added1 and then sufficient alcohol to complete the volume to the mark4 ,the flask is then attached to the condenser1 placed in a water-glycerol bath and heated to a temperature of #ge for about forty-five minutes4 ,at the end of this time1 the flask is removed from the bath and condenser1 cooled quickly with water1 alcohol added to the mark and well shaken4 ,the filtration should be accomplished with precautions1 to avoid the loss of alcohol mentioned in paragraph #bba4 ,the filtrate is examined in the polariscope in a #bjj millimeter tube1 and the reading obtained gives directly the percentage of sugar in the sample examined4 ,half the quantity of pulp mentioned1 in a #aja4c cubic centimeter flask1 may also be used4 ,a convenient form of arranging a battery of flasks is shown in the accompanying figure4 ,illustration3 ,,fig4 #ga4 ,,battery ,,for ,,alcoholic ,,digestion4 #bbd4 ,determination of ,sugar in ,mother ,beets4--,in selecting mother beets for seed production1 it is necessary to secure only those of a high sugar content4 ,this is accomplished by boring a hole about two and a half centimeters in diameter obliquely through the beet by means of the apparatus shown in ,fig4 #gb4 ,the beet is not injured for seed production by this process1 and the pulp obtained is used for the determination of sugar4 ,the juice is expressed by means of the small hand press shown in ,fig4 #gc4 ,since only a small quantity of juice is obtained1 it is advisable to prepare it for polarization in a sugar flask marked at fifty cubic centimeters4 ,the density of the juice1 by reason of its small volume1 is easiest obtained by the hydrostatic balance1 as described in paragraph #ec4 ,in lieu of this1 the juice may be quickly weighed in a counterbalanced dish on a balance giving results accurate to within one milligram4 ,the rest of the analytical process is similar to that already described4 ,illustration3 ,,fig4 #gb4 ,,rasp ,,for ,,sampling ,,mother ,,beets4 ,illustration3 ,,fig4 #gc4 ,,hand ,,press ,,for ,,beet ,,analysis4 ,illustration3 ,,fig4 #gd4 #bbe4 ,aqueous ,diffusion4--,the process of instantaneous aqueous diffusion may also be applied to the examination of mother beets4 ,for this purpose the beets are perforated by a rasp1 devised by ,keil1 shown lying on the floor in ,fig4 #gb1 the characteristics of which are shown in ,fig4 #gd4 ,the conical end of the rasp is roughened in such a way as to reduce the beet to an impalpable pulp4 ,this end is fastened by a bayonet fastening to the cylindrical carrier or arm in such a way that1 by means of a groove in the conical end of the rasp1 the pulp is introduced into the cylinder4 ,the cylinder is provided with a small piston by means of which the pulp can be withdrawn when the cylindrical portion of the rasp is detached from the driving machinery4 ,it is important that the rasp be driven at a high rate of speed1 viz41 from #aejj to #bjjj revolutions a minute4 ,the sample of pulp at this rate of revolution is taken almost instantly1 and with skilled manipulators the whole operation of taking a sample1 removing the rasp by means of its bayonet fastenings1 withdrawing the sample of pulp and replacing the rasp ready for another operation does not consume more than from ten to twenty seconds4 ,from three to four samples may thus be taken in a minute4 ,the samples of pulp as taken are dropped into numbered dishes corresponding to the numbers on the beets4 ,one-quarter of the normal weight for the polariscope is used for the analysis4 ,the pulp is placed in a fifty cubic centimeter flask1 water and lead subacetate added1 the flask well shaken1 filled to the mark with water1 again well shaken1 the contents thrown on the filter1 and the filtrate polarized in a #djj millimeter tube1 giving the direct percentage of sugar4 ,for practical purposes the percentage of marc in the beet may be neglected4 ,if the polarization take place in a #bjj millimeter tube the number obtained should be multiplied by two for the content of sugar4 ,in numbering sugar beets which are to be analyzed for seed production1 it is found that a small perforated tin tag bearing a number may be safely affixed to the beet by means of a tack4 ,it is not safe to use paper tags as they may become illegible by becoming wet before the sorting of the beets is completed4 ,where from #ajjj to #bjjj beets are to be examined in a day1 the number of the beets and the dishes corresponding thereto must be carefully controlled to avoid confusion and mistakes4 #bbf4 ,determination of ,sugars without ,weighing4--,an ingenious device for the rapid analysis of mother beets is based upon the use of a machine which cuts from the beet a core of given dimensions and this core is subsequently reduced to a pulp which is treated with cold water and polarized in the manner described above4 ,the cutting knives of the sampler can be adjusted to take a core of any desired size4 ,since the beets used for analysis have essentially the same specific gravity1 the cores thus taken weigh sensibly the same and the whole core is used for the analysis1 thus doing away with the necessity of weighing4 ,the core obtained is reduced to a pulp in a small machine so adjusted as to permit the whole of the pulp1 when prepared1 to be washed directly into the sugar flask4 ,by the use of this machine a very large number of analyses can be made in a single day1 and this is highly important in the selection of mother beets1 for often #ej1jjj or #ajj1jjj analyses are to be made in a short time4 ,illustration3 ,,fig4 #ge4 ,,tube ,,for ,,continuous ,,observation4 #bbg4 ,continuous ,diffusion ,tube4--,to avoid the delay occasioned by filling and emptying observation tubes in polariscopic work1 where large numbers of analyses of canes and beets are to be made1 ,pellet has devised a continuous diffusion tube1 by means of which a solution1 which has just been observed1 is rapidly and completely displaced by a fresh solution4 ,this tube1 improved by ,spencer1 is shown in ,fig4 #ge4 ,the fresh solution is poured in at the funnel1 displacing completely the old solution which flows out through the tube at the other end4 ,the observer watches the field vision and is able to tell when the old solution is completely displaced by the clearing of the field1 at which time the reading of the new solution can be quickly made4 ,when solutions are all ready for examination an expert observer can easily read1 by the aid of this device1 from four to five of them in a minute4 #bbh4 ,analysis of ,sirups and ,massecuites4--,the general principles which control the analysis of sirups and massecuites are the same whether these products be derived from canes or beets4 ,in the case of the products of canes1 the sirups or massecuites contain chiefly sucrose1 invert sugar1 and other copper reducing bodies1 inorganic matters and water4 ,in the case of products derived from sugar beets the contents are chiefly sucrose1 inorganic matters1 a trace of invert sugar1 raffinose and water4 ,the principles of the determination of these various constituents have already been described4 #bbi4 ,specific ,gravity4--,the specific gravity of sirups and molasses can be determined by the spindle in the usual way1 but in the case of molasses which is quite dense1 the spindle method is not reliable4 ,it is better1 therefore1 both in molasses and massecuites1 to determine the density by dilution4 ,for this purpose1 as described by ,spencer1 a definite weight of material1 from #bjj to #bej grams1 is dissolved in water and the volume of the solution completed to half a liter4 ,a portion of the solution is then placed in a cylinder and the quantity of total solids contained therein determined in the usual way by a brix or specific gravity hydrometer4 ,in case #bej grams of the material be used the calculation of the brix degree for the original material is conducted according to the following formula3 ,g ,b ,v x -------------4 ,w ,in the above formula x is the required brix degree1 ,v the volume of the solution1 ,b the observed brix degree of the solution1 and ,g the corresponding specific gravity obtained from the table on page #gc4 ,when only small quantities of the material are at hand the hydrostatic balance 7#ec7 should be employed4 ,for this purpose twenty-five grams of the material are dissolved in water and the volume of the solution made up to #ajj cubic centimeters4 ,the sinker of the hydrostatic balance is placed in the solution and equilibrium secured by placing the weights upon the arm of the balance in the usual manner4 ,since the arm of the balance is graduated to give1 by direct reading1 the specific gravity1 the density can be obtained at once4 ,example4--,let the position of the weights or riders upon the balance arm be as follows3 7#a7 at point of suspension of the bob #a4jjj 7#c7 at mark #g on beam #j4jg 7#d7 at mark #i on beam #j4jji ,specific gravity #a4jgi ,the nearest brix degree corresponding to this specific gravity 7#eh7 is #ai4 ,the total weight of the solution is equal to #ajj #a4jgi1 viz41 #ajg4i grams4 ,since the solution contains nineteen per cent of solid matter as determined by the hydrostatic balance1 the total weight of solid matter therein is #ajg4i #ai #ajj #bj4e grams4 ,the total per cent4 of solid matter in the original sample is therefore #bj4e #be #ajj #hb and the specific gravity corresponding thereto 7page #gd7 is #a4dbicd4 ,the specific gravity of a massecuite may also be determined in pyknometers especially constructed for this purpose4#ahf #bcj4 ,determination ,of ,water4--,the accurate determination of water in sirups and massecuites is a matter of considerable difficulty4 ,the principles of conducting the process 7#bf71 applicable also to the determination of water in honeys and other viscous liquids1 are as follows3 ,in all cases where invert sugar is present the drying should be conducted at a temperature not exceeding #ge or #hj4 ,in dense molasses and massecuites a weighed quantity should be dissolved and made up to a definite volume and an aliquot portion taken for the determination4 ,in order to secure complete desiccation at a low temperature1 the drying should be accomplished in partial vacuum 7pages #bb1 #bc74 ,the process of desiccation should be conducted in shallow1 flat-bottom dishes which may be conveniently and cheaply made of aluminum and the process is hastened by filling the dish previously with thoroughly dried fragments of pumice stone4 ,when the sample does not contain any invert sugar the desiccation can be safely accomplished at the temperature of boiling water4 ,drying should be continued in all cases until practically constant weight is obtained4 #bca4 ,determination ,of ,ash4--,ash is an important constituent of the sirups1 molasses1 and massecuites from canes and exists in very much larger quantities in the same products from beets4 ,the ash may be determined directly by careful incineration1 but it is customary to add a few drops of sulfuric acid1 sufficient to combine with all the bases present and be in slight excess4 ,the presence of sulfuric acid is of some advantage in the beginning of the carbonization and renders the process somewhat easier of accomplishment4 ,when sulfuric acid is used1 the weight of ash obtained must be diminished by one-tenth to allow for the increased weight obtained by the conversion of the carbonates into sulfates4 ,in general1 the principles and methods described on pages #cf-dj are to be employed4 #bcb4 ,determination of ,reducing ,sugars in ,sirups1 ,molasses1 and ,massecuites4--,the quantity of reducing sugars in the products derived from the sugar beet1 as a rule1 is insignificant4 ,in the products from sugar cane there are large quantities of reducing matters which1 in general1 are determined by any of the standard methods already given4 ,it has been shown by the author#ahg that the juices of healthy sugar canes contain a small quantity of invert sugar1 but this statement has been contradicted by ,bloufret4#ahh ,it is certain1 however1 that the reducing bodies derived from the products of manufacture of sugar cane and sorghum deport themselves in a manner somewhat different from pure invert sugar4 ,in the absence of definite information in respect of the constitution of these bodies1 the methods applicable to dextrose and invert sugar may be applied4 ,since the paragraphs relating to these processes were printed some important improvements in the preparation of the alkaline copper solutions have been made4 ,the copper carbonate solution1 as has already been said1 is peculiarly suited to the determination of reducing sugars in the presence of sucrose and the modified forms of this solution1 and the methods of employing them with invert sugar1 dextrose1 levulose1 and maltose1 are described below4 #bcc4 ,estimation of ,minute ,quantities of ,invert ,sugar in ,mixtures4--,the method of ,hiller and ,meissl1 paragraph #adb1 may be used for the estimation of small quantities of invert sugar in mixtures4 ,a modified form of ,soldaini's reagent is1 however1 to be preferred for this purpose4 ,ost has proposed and tested a copper carbonate solution for the purpose mentioned which gives reliable results4#ahi ,the solution has the following composition3 ,one liter contains #c4f grams crystallized copper sulfate4 #bej4j 0 potassium carbonate4 #ajj4j 0 hydrogen potassium sulfate4 ,this reagent undergoes no change when kept for a long while1 especially in large vessels4 ,even in smaller vessels it can be kept for a year or more without undergoing any change4 ,the method of analysis is the same as that described in paragraph #abh1 with the exception that the boiling is continued for only five minutes instead of ten1 and the quantities of the copper and sugar solutions used are doubled1 being #ajj and fifty cubic centimeters respectively4 ,in no case must the solution used contain more than thirty-eight milligrams of invert sugar4 ,the quantity of sucrose in the mixture is obtained by polarization 7#id74 ,ost has also recalculated the reduction values of the common sugars for the strong copper carbonate solution1 and the numbers obtained are slightly different from those given on page #adb4aij ,for different percentages of invert sugar in mixtures of sucrose1 the quantities of invert sugar are calculated from the number of milligrams of copper obtained by the following table3 7,a7 ,milligrams of copper obtained4 7,b7 ,pure invert sugar4 7,c7 ,invert sugar4 7,d7 ,sucrose4 ,,milligrams ,,of ,,invert ,,sugar ,,in ,,mixtures ,,of #e7;,c7 #b7;,c7 #a4e7;,c7 #a4j7;,c7 #j4h 7,c7 #j4f7;,c7 #j4e7;,c7 7,a7 7,b7 #ie7;,d7 #ih7;,d7 #ih4e7;,d7 #ii4j7;,d7 #ii4b 7,d7 #ii4d7;,d7 #ii4e7;,d7 #hh #cg4i #cg4a #cf4j #ce4d #cd4g #cd4b #cc4i #cc4f #he #cf4c #ce4e #cd4e #cd4j #cc4d #cb4i #cb4e #cb4b #hj #cc4i #cc4j #cc4b #ca4g #ca4b #cj4g #cj4b #bi4i #ge #ca4f #cj4g #cj4j #bi4e #bi4j #bh4e #bh4a #bg4g #gj #bi4d #bh4e #bg4h #bg4d #bf4h #bf4d #be4i #be4f #fe #bg4c #bf4c #be4g #be4c #bd4g #bd4c #bc4h #bc4e #fj #be4b #bd4b #bc4f #bc4b #bb4f #bb4b #ba4h #ba4e #ee #bc4a #bb4a #ba4f #ba4b #bj4f #bj4b #ai4h #ai4f #ej #ba4b #bj4a #ai4f #ai4b #ah4f #ah4c #ag4i #ag4g #de #ai4c #ah4b #ag4f #ag4b #af4g #af4c #af4j #ae4h #dj #ag4c #af4c #ae4g #ae4c #ad4h #ad4e #ad4b #ad4j #ce #ae4d #ad4e #ac4h #ac4d #ac4j #ab4g #ab4e #ab4c #cj #ac4e #ab4f #ab4j #aa4f #aa4b #aa4j #aj4h #aj4f #be #aa4e #aj4h #aj4c #aj4j #i4e #i4c #i4a #i4j #bj #i4f #i4a #h4f #h4c #g4i #g4g #g4e #g4c #ae #g4g #g4c #f4i #f4g #f4c #f4a #e4h #e4f #aj #e4h #e4d #e4a #e4j #d4g #d4e #d4b #c4i ,,milligrams ,,of ,,invert ,,sugar ,,in ,,mixtures ,,of #j4d7;,c7 #j4c7;,c7 #j4b7;,c7 #j4a7;,c7 #j4je7;,c7 #j4jb7;,c7 7,a7 #ii4f7;,d7 #ii4g7;,d7 #ii4h7;,d7 #ii4i7;,d7 #ii4ie7;,d7 #ii4ih7;,d7 #hh #cc4c #he #cb4j #ca4h #hj #bi4g #bi4e #ge #bg4d #bg4b #gj #be4c #be4j #fe #bc4b #bb4h #fj #ba4b #bj4h #bj4d #ee #ai4c #ah4i #ah4e #ej #ag4d #ag4j #af4g #de #ae4f #ae4c #ad4i #dj #ac4h #ac4e #ac4b #ce #ab4a #aa4i #aa4e #aj4c #cj #aj4d #aj4b #i4i #h4h #be #h4h #h4f #h4b #g4c #bj #g4a #f4i #f4f #e4h #d4i #ae #e4d #e4b #e4j #d4d #c4g #b4j #aj #c4h #c4e #c4d #c4j #b4e #a4g #bcd4 ,soldaini's ,method ,adapted to ,gravimetric ,work4--,by reason of their better keeping qualities and because of their less energetic action on non-reducing sugars1 copper carbonate solutions are to be preferred to the alkaline copper tartrate solutions for gravimetric determinations of reducing sugars in cane juices and sugar house products1 provided the difficulties which attend the manipulation can be removed4 ,ost has succeeded in securing perfectly satisfactory results with copper carbonate solution by slightly varying the composition thereof and continuing the boiling1 for the reduction of the copper1 ten minutes4#aia ,the copper solution is made as follows3 #ag4e grams crystallized copper sulfate4 #bej4j 0 potassium carbonate4 #ajj4j 0 0 bicarbonate4 ,the above ingredients are dissolved in water and the volume of the solution completed to one liter4 ,the object of the potassium bicarbonate is to secure in the solution an excess of carbon dioxid and thus prevent the deposition of basic copper carbonate on keeping4 ,the manipulation is conducted as follows3 ,one hundred cubic centimeters of the copper solution are mixed with half that quantity of the sugar solution in a large erlenmeyer1 which is placed upon a wire gauze1 heated quickly to boiling and kept in ebullition just ten minutes4 ,the sugar solution should contain not less than eighty nor more than #aej milligrams of the reducing sugar1 and the quantity of the solution representing this should be diluted to fifty cubic centimeters before mixing with the copper solution4 ,after boiling1 the contents of the erlenmeyer are quickly cooled and filtered with suction through an asbestos filter and the whole of the copper suboxid washed into the filter tube4 ,this precipitated suboxid is washed once with a little potassium carbonate solution then with hot water and finally with alcohol1 well dried1 heated to redness1 and the copper oxid obtained reduced to metallic copper in an atmosphere of hydrogen entirely free of arsenic4 ,from the weight of metallic copper obtained the quantity of sugar which has been oxidized is calculated from the tables below4 ,it is evident that the process given above may be varied so as to conform to the practice observed in this laboratory of cooling the boiling solution sufficiently at once by adding to it an equal volume of recently boiled1 cold water1 collecting the precipitated copper suboxid in a gooch1 and1 after washing it1 securing solution in nitric acid and the precipitation of the copper by electrolysis4 ,,table ,,showing ,,milligrams ,,dextrose1 ,,levulose ,,and ,,invert ,,sugar ,,oxidized1 ,,corresponding ,,to ,,milligrams ,,of ,,copper ,,reduced4 ,copper4 ,dextrose4 ,levulose4 ,invert4 #dce #aeb4c #ade4i #adg4e #dcj #adi4h #adc4d #ade4c #dbe #adg4c #adj4i #adc4a #dbj #add4h #ach4d #adj4h #dae #adb4c #ace4i #ach4e #daj #aci4h #acc4e #acf4b #dje #acg4c #aca4a #acc4i #djj #acd4i #abh4g #aca4f #cie #acb4e #abf4d #abi4c #cij #acj4a #abd4a #abg4j #che #abg4h #aba4h #abd4h #chj #abe4e #aai4e #abb4f #cge #abc4c #aag4b #abj4d #cgj #aba4a #aae4j #aah4b #cfe #aai4j #aab4h #aaf4j #cfj #aaf4i #aaj4f #aac4i #cee #aad4h #ajh4e #aaa4h #cej #aab4h #ajf4d #aji4h #cde #aaj4h #ajd4c #ajg4h #cdj #ajh4h #ajb4c #aje4h #cce #ajf4h #ajj4c #ajc4h #ccj #ajd4i #ih4d #aja4h #cbe #ajc4j #if4e #ii4i #cbj #aja4a #id4f #ih4j #cae #ii4b #ib4h #if4b #caj #ig4d #ia4j #id4d #cje #ie4f #hi4b #ib4f #cjj #ic4h #hg4e #ij4i #bie #ib4j #he4h #hi4b #bij #ij4b #hd4a #hg4e #bhe #hh4d #hb4d #he4h #bhj #hf4g #hj4h #hd4a #bge #he4j #gi4b #hb4d #bgj #hc4c #gg4f #hj4g #bfe #ha4e #gf4a #gi4a #bfj #gi4h #gd4f #gg4e #bee #gh4a #gc4a #ge4i #bej #gf4e #ga4f #gd4c #bde #gd4i #gj4a #gb4g #bdj #gc4c #fh4f #ga4a #bce #ga4g #fg4b #fi4e #bcj #gj4a #fe4g #fh4j #bbe #fh4e #fd4c #ff4e #bbj #ff4i #fb4h #fe4j #bae #fe4c #fa4d #fc4e #baj #fc4h #ei4i #fb4j #bje #fb4b #eh4e #fj4e #bjj #fj4g #eg4j #ei4j #aie #ei4a #ee4f #eg4e #aij #eg4f #ed4a #ef4j #ahe #ef4j #eb4g #ed4e #ahj #ed4e #ea4b #ec4a #age #ec4j #di4h #ea4f #agj #ea4e #dh4d #ej4b #afe #ej4j #df4i #dh4g #afj #dh4e #de4e #dg4c #aee #dg4j #dd4a #de4h #aej #de4e #db4g #dd4d #ade #dd4j #da4c #db4i #adj #db4e #ci4i #da4e #ace #da4j #ch4e #dj4a #acj #ci4f #cg4a #ch4f #abe #ch4a #ce4g #cg4b #abj #cf4g #cd4c #ce4h #aae #ce4b #cb4i #cd4c #aaj #cc4g #ca4f #cb4i #aje #cb4b #cj4c #ca4d #ajj #cj4g #bi4j #cj4j #ie #bi4b #bg4g #bh4e #ij #bg4h #bf4d #bg4a #he #bf4c #be4a #be4f #hj #bd4h #bc4h #bd4b #ge #bc4c #ba4e #bb4h #gj #ba4h #bj4b #ba4d ,,corresponding ,,table ,,for ,,maltose4 ,milligrams ,milligrams ,milligrams maltose maltose copper anhydrid hydrate obtained4 oxidized4 oxidized4 #dce #bfc4g #bgg4f #dcj #bei4c #bgc4j #dbe #bee4j #bfh4d #dbj #bej4i #bfd4a #dae #bdg4j #bfj4j #daj #bdc4b #bef4j #dje #cci4d #beb4j #djj #bce4f #bdh4j #cie #bca4i #bdd4a #cij #bbh4b #bdj4b #che #bbd4f #bcf4d #chj #bba4a #bcb4g #cge #bag4g #bbi4a #cgj #bad4d #bbe4f #cfe #baa4a #bbb4b #cfj #bjg4i #bah4h #cee #bjd4g #bae4d #cej #bja4e #bab4a #cde #aih4c #bjh4g #cdj #aie4b #bje4d #cce #aib4j #bjb4a #ccj #ahh4h #aih4h #cbe #ahe4g #aie4d #cbj #ahb4e #aib4a #cae #agi4d #ahh4h #caj #agf4c #ahe4f #cje #agc4c #ahb4d #cjj #agj4c #agi4b #bie #afg4c #agf4a #bij #afd4d #agc4j #bhe #afa4d #afi4i #bhj #aeh4e #aff4h #bge #aee4e #afc4g #bgj #aeb4f #afj4g #bfe #adi4g #aeg4f #bfj #adf4h #aed4f #bee #adc4i #aea4e #bej #ada4a #adh4e #bde #ach4b #ade4e #bdj #ace4d #adb4e #bce #acb4e #aci4e #bcj #abi4g #acf4e #bbe #abf4h #acc4e #bbj #abd4j #acj4f #bae #aba4b #abg4f #baj #aah4d #abd4g #bje #aae4g #aba4h #bjj #aab4i #aah4i #aie #aaj4b #aaf4j #aij #ajg4d #aac4a #ahe #ajd4g #aaj4b #ahj #aja4i #ajg4c #age #ii4b #ajd4d #agj #if4d #aja4e #afe #ic4g #ih4f #afj #ij4i #ie4g #aee #hh4b #ib4h #aej #he4d #hi4i #ade #hb4f #hg4j #adj #gi4i #hd4a #ace #gg4a #ha4b #acj #gd4d #gh4c #abe #ga4f #ge4d #abj #fh4i #gb4e #aae #ff4a #fi4f #aaj #fc4d #ff4g #aje #fj4f #fc4h #ajj #eg4i #fj4i #ie #ee4a #eh4j #ij #eb4c #ee4a #he #di4f #eb4b #hj #df4h #ei4c #ge #dd4a #ef4d #gj #da4d #ec4e #bce4 ,weighing the ,copper as ,oxid4--,in the usual methods of the determination of reducing bodies1 the percentage is calculated either volumetrically from the quantity of the sugar solution required to decolorize a given volume of the alkaline copper solution1 or the reduced copper suboxid is brought into a metallic state by heating in an atmosphere of hydrogen or by electrolytic deposition4 ,a quicker method of procedure is found in completing the oxidation of the cupric oxid by heating to low redness in a current of air4#aib ,for this determination the precipitation of the cuprous oxid and its filtration are made in the usual manner4 ,the cuprous oxid is collected in a filtering tube1 made by drawing out to proper dimensions a piece of combustion tube1 and has a length of about twelve centimeters in all4 ,the unchanged part of the tube is about eight centimeters in length and twelve millimeters in diameter4 ,it is filled by first putting in a plug of glass wool and covering this with an asbestos felt on top of which another plug of glass wool is placed4 ,after the cuprous oxid is collected in the tube it is washed with boiling water1 alcohol and ether4 ,the rubber tube connecting it with the suction is of sufficient length to permit the tube being taken in one hand and brought into a horizontal position over a bunsen4 ,the tube is gradually heated1 rotating it meanwhile1 until any residual moisture1 alcohol or ether1 is driven off from the filtering material4 ,the layer of glass wool holding the cuprous oxid is gradually brought into the flame and as the oxidation begins the material will be seen to glow4 ,the heating is continued for some time after the glowing has ceased1 in all for three or four minutes1 the tube and the copper oxid which it contains being brought to a low redness4 ,the current of air passing over the red-hot material in this time oxidizes it completely4 ,the filtering tube1 before use1 must be ignited and weighed in exactly the same manner as described above4 ,the heat is so applied as not to endanger the rubber tube attached to one end of the filtering tube nor to burn the fingers of the operator as he turns the tube during the heating4 ,after complete oxidation the tube is cooled in a desiccator and weighed1 the increase of weight giving the copper oxid4 ,for the atomic weights1 #fc4c copper and #ae4if oxygen1 one gram of copper oxid is equivalent to #j4gihfd gram of copper1 and for the weights #fc4ag copper and #ae4if oxygen1 one gram of copper oxid equals #j4gihca gram of copper4 ,from the amount of metallic copper calculated by one of these factors1 the reducing sugar is determined by the tables already given4 #bcf4 ,estimation of ,dry ,substance1 ,polarization and ,apparent ,purity for ,factory ,control4--,for technical purposes the methods of determining the above factors1 proposed by ,weisberg and applicable to concentrated sirups1 massecuites1 and molasses1 may be used4#aic ,five times the half normal quantity of the material1 viz41 #fe4ab grams1 are placed in a quarter liter flask1 dissolved in water and the flask filled to the mark4 ,in the well shaken mixture1 which is allowed to stand long enough to be free of air1 the degree brix is estimated by an accurate spindle4 ,for example1 in the case of molasses1 let the number obtained be #ah4h4 ,fifty cubic centimeters of the solution are poured into a #ajj cubic centimeter flask1 the proper quantity of lead subacetate added1 the flask filled to the mark with water1 its contents filtered1 and the filtrate polarized in a #bjj millimeter tube4 ,let the number obtained on polarization be #bb4a4 ,this number may be used in two ways4 ,if it be multiplied by two the polarization of the original sample is obtained2 in this case1 viz41 #dd4b4 ,in the second place1 if #dd4b be multiplied by #j4bfjdh and this product divided by the specific gravity corresponding to #ah4h4 viz41 #a4jgh1 the quotient #aj4fh is secured representing the polarization or per cent of sugar contained in the solution of which the degree brix was #ah4h4 ,from the numbers #ah4h and #aj4fh the apparent purity of the solution1 #ef4h1 is calculated1 viz41 #aj4fh #ajj by #ah4h4 ,the original product as calculated above gives a polarization of #dd4b and this number multiplied by #ajj and divided by #ef4h gives #gg4h1 or the apparent percentage of dry matter4 ,the original sample of molasses1 therefore1 had the following composition3 ,degree brix 7total solids7 #gg4h per cent4 ,sucrose #dd4b 0 ,solids1 not sucrose #cc4f 0 ,apparent purity #ef4h 0 ,it is seen from the above that with a single weighing and a single polarization1 and within from ten to fifteen minutes1 all needful data in respect of the proper treatment of molasses for the practical control and direction of a factory can be obtained4 ,in case a laurent polariscope is used1 five times the normal weight1 viz41 eighty-one grams of the raw material are used and the process conducted as above4 ,,sucrose1 ,,dextrose1 ,,invert ,,sugar1 ,,levulose1 ,,maltose1 ,,raffinose1 ,,dextrin ,,and ,,lactose ,,in ,,mixtures4 #bcg4 ,occurrence4--,sucrose and invert sugar are found together in many commercial products1 especially in raw sugars and molasses made from sugar cane1 and in these products sucrose is usually predominant4 ,they also form the principal saccharine contents of honey1 the invert sugar1 in this case1 being the chief ingredient4 ,in commercial grape sugar1 made from starch1 dextrose is the important constituent1 while in the hydrolysis of starch by a diastatic ferment1 maltose is principally produced4 ,in the manufacture of commercial glucose by the saccharification of starch with sulfuric acid1 dextrin1 maltose1 and dextrose are the dominant products1 while in the similar substance midzu ame1 maltose and dextrose are chiefly found1 and only a small quantity of dextrose4#aid ,in honeys derived from the exudations of coniferous trees are found also polarizing bodies not enumerated above and presumably of a pentose character4#aie ,in evaporated milks are usually found large quantities of sucrose in addition to the natural sugar therein contained4 ,these mixtures of carbohydrates often present problems of great difficulty to the analyst1 and the following paragraphs will be devoted to an elucidation of the best approved methods of solving them4 ,,optical ,,methods4 #bch4 ,sucrose and ,invert ,sugar4--,the chemical methods of procedure to be followed in the case of a sample containing both sucrose and invert sugar have been given in sufficient detail in preceding paragraphs 7#abd1 #aga74 ,when1 however1 it is desirable to study further the composition of the mixture1 important changes in the method are rendered imperative4 ,while the estimation of the sucrose and the total invert sugar1 or the sum of the dextrose and levulose1 is easy of accomplishment the separate determination of the dextrose and levulose is not so readily secured4 ,in the latter case the total quantity of the two sugars may be determined1 and after the destruction or removal of one of them the other be estimated in the usual way2 or in the mixture the levulose can be determined by the variation in its gyrodynat1 caused by changes of temperature4 #bci4 ,optical ,neutrality of ,invert ,sugar4--,the gyrodynat of levulose decreases as the temperature rises 7#ajg7 and at or near a temperature of #hg4b1 it becomes equal to that of dextrose1 and1 therefore1 pure invert sugar composed of equal molecules of levulose and dextrose is optically neutral to polarized light at that temperature4 ,on this fact ,chandler and ,ricketts have based a method of analysis which excludes any interference in polarization due to invert sugar4#aif ,to secure the polarization at approximately a temperature of #hg1 a water-bath is placed between the nicols of an ordinary polariscope in such a way as to hold a tubulated observation tube in the optical axis of the instrument4 ,the ends of the bath1 in the prolongation of this axis1 are provided with clear glass disks4 ,the space between the cover glasses of the observation tube and the glass disks of the bath is occupied by the water of the bath4 ,when this is kept at a constant temperature it does not interfere with the reading4 ,the observation tube may be of glass1 but preferably is constructed of metal plated with platinum on the inside4 ,for the most exact work the length of the observation tube1 at #hg1 is determined by measurement or calculation4 ,the bath is heated with alcohol lamps or other convenient means4 ,the arrangement of the apparatus is shown in ,fig4 #ge4 ,in a mixture of sucrose and invert sugar any rotation of the plane of polarized light at #hg is due to the sucrose alone4 ,in a mixture of dextrose and sucrose the polarization is determined1 and1 after inversion1 again determined at #hg4 ,the latter number is due to dextrose alone1 and the difference between the two gives the rotation due to sucrose4 ,illustration3 ,,fig4 #ge4--;,,chandler ,,and ,,ricketts' ,,polariscope4 #bdj4 ,sucrose and ,raffinose4--,in raw sugars made from beet molasses considerable quantities of raffinose are found4 ,the method of inversion and polarization in such cases is described in paragraph #ajj4 ,in making the inversion by the method proposed by ,lindet 7#ie71 and conducting the polarization on a laurent instrument1 a slightly different formula1 given below1 is used2 viz43 ,c - #j4dhia;,a ,s --------------- #j4haj ,a - ,s and ,r ----------1 #a4ed in which the several letters refer to the same factors as are indicated by them in the formula of ,creydt4 ,in the application of the formula just given the normal weight of the mixed raw sugars used is #af4b grams4#aig #bda4 ,optical ,determination of ,levulose4--,the determination of levulose by optical methods alone is made possible by reason of the fact that the gyrodynats of the sugars with which it is associated are not sensibly affected by changes of temperature4 ,the principle of the process1 as developed by the author1 rests on the ascertainment of the change in the gyrodynat of levulose when its rotation is observed at widely separated temperatures4#aih ,the observation tube employed for reading at low temperatures is provided with desiccating end tubes1 which prevent the deposition of moisture on the cover glasses4 ,the relations of this device to the optical parts of the apparatus are illustrated in ,fig4 #gf4 ,illustration3 ,,fig4 #gf4--;,,apparatus ,,for ,,polarimetric ,,observations ,,at ,,low ,,temperatures4 ,the protecting tubes are made of hard rubber and the desiccation is secured by surrounding the space between the rubber and the perforated metal axis with fragments of potash or calcium chlorid4 ,the details of the construction are shown in a horizontal section through the center of the observation tube in ,fig4 #gg4 ,in this figure the observation tube1 made of glass or metal1 is represented by i1 the metal jacket1 open at the top in the ,v shape as described1 by k4 ,the observation tube is closed by the heavy disk b made of non-polarizing glass4 ,this disk is pressed against the end of the observation tube by the rubber washer a1 when the drying system about to be described is screwed on to k4 ,the apparatus for keeping the cover glass dry is contained in the hard rubber tube m and consists of a perforated cylinder of brass e1 supported at one end by the perforated disk c and at the outer ends by the arms d4 ,it is closed by a cover glass of non-polarizing glass s and can be screwed on to the system h at n4 ,the space p is filled with coarse fragments of caustic soda1 potash1 or calcium chlorid by removing the cover glass s4 ,the perforated disk c prevents any of the fragments from entering the axis of observation4 ,when the cover glass s is replaced1 it just touches the free end of the perforated metal tube preventing any of the fragments of the drying material from falling into the center at the outer end4 ,when this drying tube is placed in position1 the contents of the observation tube i can be kept at the temperature of zero for an indefinite time without the deposition of a particle of moisture either upon the glass b or s4 ,illustration3 ,,fig4 #gg4--;,,construction ,,of ,,desicating ,,tube4 ,for determining the rotation at a high temperature the apparatus of ,chandler and ,ricketts 7#bch7 may be used or the following device3 ,the polarizing apparatus shown above1 ,fig4 #gf1 may be used after the ,v shape box is removed from the stand1 which is so constructed as to receive a large box covered with asbestos felt an inch thick4 ,the observation tube is held within this box in the same way as in the one just described so that the hot water extends not only the entire length of the tube but also covers the cover glasses4 ,in both cases the cover glasses are made of heavier glass and are much larger in diameter than found in the ordinary tubes for polariscopes4 ,the protecting cylinders of hard rubber are not needed at high temperatures but can be left on without detriment4 ,the illustration1 ,fig4 #gh1 shows the arrangement of the apparatus with a silver tube in position1 which can be filled and emptied without removing it4 ,illustration3 ,,fig4 #gh4--;,,apparatus ,,for ,,polarizing ,,at ,,high ,,temperatures4 ,in practice the water is heated with a jet of steam and an even temperature is secured by a mechanical stirrer kept slowly in motion4 ,with such a box it is easy to maintain a temperature for several hours which will not vary more than half a degree4 ,the temperature for reading the hot solutions was fixed at #hh1 this being nearly the temperature at which a mixture of equal molecules of levulose and dextrose is optically inactive4 ,in every case the sugar solutions were made up to the standard volume at the temperatures at which they were to be read and thus the variations due to expansion or contraction were avoided4 ,when solutions are read at a high temperature1 they must be made with freshly boiled water so as to avoid the evolution of air bubbles which may otherwise obscure the field of vision4 ,by means of the apparatus described it is easy for the analyst to make a polarimetric reading at any temperature desired4 ,in all cases the observation tube should be left at least a half an hour and sometimes longer in contact with the temperature control media before the reading is made4 ,the appearance of the field of vision is usually a pretty fair index of the point of time at which a constant temperature is established throughout all parts of the system4 ,any variation in temperature produces a distortion of the field of vision while a constant fixed temperature will disclose the field of vision in its true shape and distinctness of outline4 ,principles of the ,calculation4--,if #bf4jdh grams of pure sucrose be dissolved in water and the volume made #ajj cubic centimeters1 it will produce an angular rotation of #cd4fh when examined in a #bjj millimeter tube with polarized sodium monochromatic light4 ,upon the cane sugar scale of an accurately graduated shadow instrument the reading will be #ajj divisions corresponding to #ajj per cent of pure sucrose4 ,in the complete inversion of the cane sugar the reaction which takes place is represented by the following formula3 -- ,c,h,o ,h#j ,c,h,o ,c,h,o4 ,the minus and plus signs indicate that the resulting invert sugar is a mixture of equal parts of levulose 7d fructose7 and dextrose 7d glucose74 ,we are not concerned here with the fact that a complete inversion of cane sugar is a matter of great difficulty nor with the danger which is always experienced of destroying a part of one of the products of inversion4 ,they are matters which may cause a variation in the analytical data afterward1 but do not affect the principles on which the process is based4 ,in the inversion of #bf4jdh grams of cane sugar there are therefore produced #ac4ga grams of levulose and #ac4ga grams of dextrose or1 in all1 #bg4db grams of the mixed sugars4 ,the angular rotation which would be produced by #ac4ga grams of dextrose in a volume of #ajj cubic centimeters and through a column #bjj millimeters in length is1 with sodium light1 #ad4ec equivalent to #da4hi divisions of the cane sugar scale4 ,the specific rotatory power of a dextrose solution of the density given is almost exactly #ec1 and this number is used in the calculations4 ,in a mixture of the two sugars under the conditions mentioned and at a temperature of #j the angular rotation observed is -#ae4ae equivalent to #dc4cg divisions of the cane sugar scale4 ,the rotation due to the dextrose is #ad4ec4 ,therefore the total negative rotation due to levulose at #j is #ae4ae #ad4ec #bi4fh4 ,hence the gyrodynat of levulose at #j and in the degree of concentration noted is readily calculated from the formula #bi4fh #ajj ,d - ------------ -#ajh4bd4 #b #ac4ga ,since at #hh 7circa7 the mixture of levulose and dextrose is neutral to polarized light1 it follows that at that temperature the specific rotatory power of levulose is equal to that of dextrose1 viz41 #ec4 ,d - #ec4 ,the total variation in the specific rotatory power of levulose1 between zero and #hh1 is #ee4bd4 ,the variation for each degree of temperature1 therefore1 of the specific rotatory power of levulose is equal to #ee4bd divided by #hh1 which is equal to #j4fbh4 ,from these data it is easy to calculate the specific rotatory power of levulose for any given temperature4 ,for instance1 let it be required to determine the gyrodynat of levulose at a temperature of #bj4 ,it will be found equal to #ajh4bd - #j4fbh #bj #ie4fh4 ,the required rotatory power is then a ,d -#ie4fh4 ,in these calculations the influence of the presence of hydrochloric acid upon the rotatory power of the levulose is neglected4 ,since the variation in angular rotation in the mixture at different temperatures is due almost wholly to the change in this property of the levulose it follows that the variation for each degree of temperature and each per cent of levulose can be calculated4 ,careful experiments have shown that the variation in the rotatory power of levulose between #j and #hh is represented by a straight line4 ,for #ac4ga grams per #ajj cubic centimeters the variation for each degree of temperature is equal to #dc4cg #hh #j4di divisions on the cane sugar scale1 or #ae4ae #hh #j4agbb angular measure4 ,if #ac4ga grams of levulose in #ajj cubic centimeters produce the deviations mentioned for each degree of temperature1 one gram would give the deviation obtained by the following calculations3 ,for the cane sugar scale #j4di #ac4ga #j4jceg and for angular rotation #j4agbb #ac4ga #j4jabef4 ,the above data afford a simple formula for calculating the percentage of levulose present from the variation observed in polarizing a solution containing levulose1 provided that the quantity of levulose present is approximately fourteen grams per #ajj cubic centimeters4 ,example4--,suppose in a given case the difference of reading between a solution containing an unknown quantity of levulose at #j and #hh is equal to thirty divisions of the cane sugar scale4 ,what weight of levulose is present8 ,we have already seen that one gram in #ajj cubic centimeters produces a variation of #j4jceg division for #a4 ,for #hh this would amount to #c4adaf divisions4 ,the total weight of levulose present is therefore #cj #c4adaf #i4edi grams4 ,in the case given #bf4jdh grams of honey were taken for the examination4 ,the percentage of levulose was therefore #i4edi #ajj #bf4jdh #cf4ff per cent4 ,if it be inconvenient to determine the polarimetric observations at temperatures so widely separated as #j and #hh the interval may be made less4 ,in the above case if the readings had been made at #bj and #gj the total variation would have been only _/ of the one given1 viz41 #ag4je divisions of the cane sugar scale4 ,the calculation would then have proceeded as follows3 #j4jceg #ej #a4ghe4 ,then1 #ag4je #a4ghe #i4eeb grams of levulose1 from which the actual percentage of levulose can be calculated as above4 ,with honeys the operation is to be conducted as follows3 ,since honeys contain approximately twenty per cent of water and in the dry substance have approximately forty-five per cent of levulose1 about #ch4ej grams of the honey should be taken to get approximately #ac4h grams of levulose4 ,in the actual determination the calculations may be based on the factors above noted1 but without respect to the degree of concentration4 ,if half the quantity of dextrose noted be present its specific rotatory power is only reduced to about #eb4ge1 and this will make but little difference in the results4 ,in the case of honey #ac4jbd grams of the sample are conveniently used in the examination1 half the normal weight for the ventzke sugar scale4 ,the error1 however1 due to difference in concentration is quite compensated for by the ease of clarification and manipulation4 ,alumina cream alone is used in the clarification1 thus avoiding the danger of heating the solution to a high temperature in the presence of an excess of lead acetate4 ,an interesting fact is observed in cooling solutions of honey to #j4 ,the maximum left hand rotation is not reached as soon as the temperature reaches #j but only after it has been kept at that temperature for two or three hours4 ,the line representing the change in rotatory power in solutions of honey between #aj and #hh is practically straight but from #aj to #j1 if measured by the readings taken without delay1 it is decidedly curved2 the reading being less at first than it is afterwards4 ,after three hours the #j becomes sensibly constant and then the whole line is nearly straight1 but still with a slight deficiency in the reading at the #j4 ,for this reason the computations should be based on readings between #aj and #hh rather than on a number covering the whole range of temperature4 ,nevertheless1 if the solution be kept at #aj for three hours before the final reading is taken1 no error of any practical magnitude is introduced4 ,the calculations given above1 for the cane sugar scale1 can also be made in an exactly similar manner for angular rotation4 ,the angular variation produced by one gram of levulose for #a of temperature is #j4jabef4 ,for #hh this would become #a4ajebh4 ,suppose the total observed angular deviation in a given case between #j and #hh to be #aj4djd1 then the weight of levulose present is #aj4djd #a4ajebh #i4dac grams4 ,in the case mentioned #bf4jdh grams of honey were taken for the examination4 ,the percentage of levulose present1 therefore1 was #i4dac #ajj #bf4jdh #cf4ac4 #bda4 ,general ,formula for the ,calculation of ,percentage of ,levulose4--,let ,k deviation in divisions of the cane sugar scale or in angular rotation produced by one gram of levulose for #a temperature4 ,let ,t and t temperatures at which observations are made4 ,let ,r observed deviation in rotation4 ,let ,w weight of levulose obtained4 ,let ,l per cent of levulose required4 ,r ,then ,l --------------- ,w4 ,k7,t - t7 ,in most genuine honeys the value of ,r between #j and #hh is approximately thirty divisions of the cane sugar scale or #aj angular measure for #bf4jdh grams in #ajj cubic centimeters1 read in a #bjj millimeter tube1 or1 for #ac4jbd grams in #ajj cubic centimeters read in a #djj millimeter tube4 ,the method of analysis outlined above has been applied in the examination of a large number of honeys with most satisfactory results4 ,it can also be applied with equal facility to other substances containing levulose4 #bdb4 ,sucrose and ,dextrose4--,in mixtures these two sugars are easily determined by optical processes1 provided no other bodies sensibly affecting the plane of polarized light be present4 ,the total deviation due to both sugars is determined in the usual way4 ,the percentage of sucrose is afterwards found by the inversion method 7#ib74 ,the rotation1 in the first instance due to the sucrose1 is calculated from the amount of this body found by inversion1 and the residual rotation is caused by the dextrose4 ,the percentage of dextrose is easily calculated by a simple proportion into which the numbers expressing the gyrodynats of sucrose and dextrose enter4 ,when the readings are made on a ventzke scale the calculations are made as follows3 ,weight of sample used #bf4jdh grams4 ,first polarization #hh4e ,polarization after inversion #aj4e ,temperature #bj4j ,percentage of sucrose #eh4d ,rotation due to dextrose #cj4a ,percentage of dextrose3 #ff4e 3 #ec x 3 #cj4a2 whence x #cg4h4 ,the sample examined therefore contains #eh4d per cent of sucrose and #cg4h per cent of dextrose4 ,it is evident that the method just described is also applicable when maltose1 dextrin1 or any other sugar or polarizing body1 not sensibly affected by the process of inversion to which the sucrose is subjected1 is substituted for dextrose4 ,when1 however1 more than two optically active bodies are present the purely polariscopic process is not applicable4 ,in such cases the chemical or the combined chemical and optical methods described further on can be employed4 #bdc4 ,lactose in ,milk4--,by reason of its definite gyrodynat lactose in milk is quickly and accurately determined by optical methods1 when proper clarifying reagents are used to free the fluid of fat and nitrogenous substances4 ,soluble albuminoids have definite levogyratory powers and1 if not entirely removed1 serve to diminish the rotation due to the lactose4 ,milk casein precipitated by magnesium sulfate has the following gyrodynatic numbers assigned to it3#aii ,dissolved in water a,d -#hj 0 0 very dilute solution a,d -#hg4 0 0 dilute sodium hydroxid solution a,d -#gf4 0 0 strong potassium hydroxid solution a,d -#ia4 ,the hydrates of albumen have rotation powers which vary from a,d -#ga4dj to a,d -#gi-je4 ,from the chaotic state of knowledge concerning the specific rotating power of the various albumens1 it is impossible to assign any number which will bear the test of criticism4 ,for the present1 however1 this number may be fixed at a,d -#gj for the albumens which remain in solution in the liquids polarized for milk sugar4#bjj ,many reagents have been prepared for the removal of the disturbing bodies from milk in order to make its polarization possible4 ,among the precipitants which have been used in this laboratory may be mentioned3#bja 7#a7 ,saturated solution basic lead acetate1 specific gravity #a4ig3 7#b7 ,nitric acid solution of mercuric nitrate diluted with an equal volume of water3 7#hh47 7#c7 ,acetic acid1 specific gravity #a4jdj1 containing twenty-nine per cent acetic acid3 7#d7 ,nitric acid1 specific gravity #a4aig1 containing thirty per cent nitric acid3 7#e7 ,sulfuric acid1 specific gravity #a4bee1 containing thirty-one per cent sulfuric acid3 7#f7 ,saturated solution of sodium chlorid3 7#g7 ,saturated solution of magnesium sulfate3 7#h7 ,solution of mercuric iodid in acetic acid1 formula2 potassium iodid1 #cc4b grams2 mercuric chlorid1 #ac4e grams2 strong acetic acid1 #bj4j cubic centimeters2 water #fdj cubic centimeters4 ,alcohol1 ether1 and many solutions of mineral salts1 hydrochloric and other acids are also used as precipitants for albumen1 but none of them presents any advantages4 ,experience has shown that the best results in polariscopic work are secured by the use of either the mercuric iodid or the acid mercuric nitrate for clarifying the milk4 ,the latter reagent should be used in quantities of about three cubic centimeters for each #ajj of milk4 ,it is evident when it is desired to determine the residual nitrogen in solution1 the former reagent must be employed4 ,the quantity of albuminoid matter left in solution after clarification with mercurial salts is so minute as to exert no sensible effect on the rotation of the plane of polarized light produced by the lactose4 ,for purposes of calculation the gyrodynat of lactose in the ordinary conditions of temperature and concentration may be represented by a,d #eb4e 7#ajg74 ,polarization4--,the proper weight of milk is placed in a sugar flask1 diluted with water1 clarified with the mercuric salt1 the volume completed to the mark1 and the contents shaken and poured on a filter4 ,the filtrate is polarized in tubes of convenient length4 ,the observed rotation may be expressed either in degrees of angular measurement or of the sugar scale4 ,the weight of milk used may be two or three times that of the normal weight calculated for the instrument employed4 ,instead of weighing the milk a corresponding volume determined by its specific gravity may be delivered from a burette-pipette 7p4 #bca74 ,for the laurent polariscope three times1 and for the half-shadow instruments for lamplight1 twice the normal weight of milk should be used4 ,for approximately sixty cubic centimeters of milk the flask should be marked at #aje cubic centimeters in compensation for the volume of precipitated solids or the reading obtained from a #ajj cubic centimeter flask1 decreased by one-twentieth4 ,for the laurent instrument the normal weight of lactose is determined by the following proportions3 ,gyrodynat of sucrose1 #ff4e3 lactose3 #eb4e x3 #af4ai4 ,whence x #bj4ea1 that is1 the number of grams of pure lactose in #ajj cubic centimeters required to read #ajj divisions of the sugar scale of the instrument4 ,for the ventzke scale the normal quantity of lactose required to read #ajj divisions is found from the following equation3 #ff4d3 #eb4e x3 #bf4jdh ,whence x #cb4gd4 ,in the one case three times the normal weight of milk is #fa4ec and in the other twice the normal weight1 #fe4dh grams4 #bdd4 ,error due to ,volume of ,precipitate4--,vieth states that the volume allowed for the precipitated solids in the original process1 viz41 two and four-tenths cubic centimeters1 is not sufficiently large4#bjb ,in such cases it is quite difficult to decide on any arbitrary correction based on the supposed quantities of fat and albuminoids present4 ,a better method than to try to compensate for any arbitrary volume is to remove entirely the disturbing cause or eliminate it by indirect means4 ,to wash the precipitate free of sugar without increasing the bulk of the filtrate unduly would be extremely difficult and tend1 moreover1 to bring some of the precipitated matters again into solution4 ,it is better1 therefore1 to eliminate the error by double dilution and polarization 7#hf74 ,the principle of this method is based on the fact1 that1 within limits not sensibly affecting the gyrodynat by reason of different densities1 the polarizations of two solutions of the same substance are inversely proportional to their volumes4 ,for convenience1 it is recommended that the volumes of the samples in each instance be #ajj and #bjj cubic centimeters1 respectively1 in which case the true reading is obtained by the simple formula given in the latter part of #hf4 ,in this laboratory the double dilution method of determining the volume of the precipitate is conducted as follows3#bjc ,in each of two flasks marked at #ajj and #bjj cubic centimeters1 respectively1 are placed #fe4eb grams of milk1 four cubic centimeters of mercuric nitrate added1 the volume completed to the mark and the contents of the flask well shaken4 ,after filtering1 the polarization is made in a #djj millimeter tube by means of the triple shadow polariscope described in #ge4 ,from the reading thus obtained the volume of the precipitate and the degree of correction to be applied are calculated as in the subjoined example4 ,the flasks should be filled at near the temperature at which the polarizations are made and the observation room must be kept at practically a constant temperature of #bj to avoid the complications which would be produced by changes in the gyrodynat of lactose and the value of the quartz plates and wedges of the apparatus by marked variations in temperature4 ,example4--,weight of milk used in each case #fe4eb grams4 ,polarimetric reading from the #ajj cubic centimeter flask1 #bj4hd 0 0 0 0 #bjj 0 0 0 #aj4ae ,then #aj4ae #b #bj4cj #bj4hd - #bj4cj #j4ed #j4ed #b #a4jh #bj4hd - #a4jh #ai4gf #ai4gf #d #d4id1 which is the corrected reading showing the percentage of lactose in the sample used4 ,the volume of the precipitate is calculated as follows3 #bj4hd #d #e4ba1 the apparent percentage of lactose present4 ,then #e4ba3 #d4id #ajj3 x4 ,whence x #id4hb4 ,from this number it is seen that the true volume of the milk solution polarized is #id4hb instead of #ajj cubic centimeters1 whence the volume occupied by the precipitate is #ajj - #id4hb #e4ah cubic centimeters4 ,so little time is required to conduct the analysis by the double dilution method as to render it preferable in all cases where incontestable data are desired4 ,where arbitrary corrections are made the volume allowed for the precipitate may vary from two and a half cubic centimeters in milks poor in fat1 to six for those with a high cream content4 ,for milks of average composition sufficient accuracy is secured by making an arbitrary correction of five cubic centimeters for the volume of the precipitate4 ,,separation ,,of ,,sugars ,,by ,,chemical ,,and ,,chemical-,,optical ,,methods4 #bde4 ,conditions of ,separation4--,in the foregoing paragraphs the optical methods for determining certain sugars have been described4 ,many cases arise1 however1 in which these processes are inapplicable or insufficient4 ,in these instances1 the analyst1 as a rule1 will be able to solve the problem presented by the purely chemical methods which have been previously described1 or by a combination of the chemical and optical processes4 ,not only have the different sugars distinctive relations to polarized light1 but also they are oxidized by varying quantities of metallic salts and these differences are sufficiently pronounced to secure in nearly every instance1 no matter how complex1 data of a high degree of accuracy4 ,the carbohydrates of chief importance1 from an agricultural point of view1 are starch and sucrose2 while the alternation products of chief importance1 derived therefrom by chemical and biological means1 are dextrin1 maltose1 dextrose and invert sugar4 #bdf4 ,sucrose1 ,levulose1 and ,dextrose4--,the purely chemical methods of separating these three sugars have been investigated by ,wiechmann4#bjd ,they are based on the data obtained by determining the percentage of reducing sugars1 both before and after the inversion of the sucrose1 and before and after the removal of the levulose4 ,for the destruction of the levulose1 the method of ,sieben is employed1 and attention is called to the fact that the complete removal of the levulose by this process is difficult of accomplishment1 and is probably attended with alterations of the other sugars present4 #bdg4 ,sieben's ,method of ,determining ,levulose4--,the decomposing action of hot hydrochloric acid on levulose1 and its comparative inaction on dextrose are the basis of ,sieben's process4#bje ,the hydrochloric acid employed should contain about #bbj grams of the pure gas per liter1 that is1 be of twenty-two per cent strength1 corresponding to #a4ajh specific gravity4 ,if the substance acted on be invert sugar1 its solution should be approximately of two and a half per cent strength4 ,to #ajj cubic centimeters of such a solution1 sixty of the hydrochloric acid are added1 and the mixture immersed in boiling water for three hours4 ,after quickly cooling1 the acid is neutralized with sodium hydrate of thirty-six times normal strength4 ,ten cubic centimeters of the hydrate solution will thus neutralize the sixty of hydrochloric acid which have been used to destroy the levulose4 ,the work of ,wiechmann discloses the fact1 easily prevised1 that the method used for destroying levulose is not always effective and that action of the reagent is not exclusively confined to the levogyrate constituent of the mixture4 ,nevertheless1 data of reasonable accuracy may be secured by this process1 which is best carried out as described by ,wiechmann4 ,in this connection the possibility of the polymerization of the dextrose molecules1 when heated with hydrochloric acid1 must not be overlooked4 #bdh4 ,the ,analytical ,process4--,the total quantity of invert sugar in a given solution is determined by the methods already given 7#acf1 #ada47 ,after this has been accomplished1 the levulose is destroyed as described above1 and the dextrose determined by any approved method 7#acf1 #adj74 ,in the presence of sucrose1 the sum of the reducing sugars is first determined as in #acf1 #adb4 ,after the inversion of the sucrose1 the invert sugar is again determined1 and the increased quantity found1 calculated to sucrose4 ,the levulose is then destroyed by hydrochloric acid1 and the dextrose determined as described above4 ,the quantity of sucrose may also be determined by an optical method 7#ia1 #ib1 #id474 #bdi4 ,calculation of ,results4--,if we represent by a the weight of metallic copper reduced by the invert sugar present in a solution containing sucrose1 and by b that obtained after the inversion of the sucrose1 the quantity of copper corresponding to the sucrose is b - a c4 ,after the destruction of the levulose1 the copper reduced by the residual dextrose may be represented by d4 ,the weight of copper equivalent to the levulose is1 therefore1 b - d e4 ,from the tables already given1 the corresponding quantities of the sugars equivalent to c1 d1 and e are directly taken4 ,example3 #afc4h milligrams invert sugar4 a #cjj milligrams #aef4e 0 dextrose4 #ahe4fc 0 levulose4 b #ejj 0 d #bge 0 #adb4h 0 dextrose4 c #bjj 0 #ajf4c 0 invert sugar4 e #bbe 0 #acc4hi 0 levulose4 ,the #ajf4c milligrams of invert sugar equivalent to c1 correspond to #aja milligrams of sucrose4 ,the quantity of dextrose equivalent to #bge milligrams of copper is #adb4h4 ,of this amount #ec4ae milligrams are due to the inverted sucrose1 leaving #hi4fe milligrams arising from the invert sugar and dextrose originally present4 ,this quantity is equivalent to #age milligrams of copper4 ,of the #cjj milligrams of copper obtained in the first instance1 #abe are due to levulose in the original sample1 corresponding to #fi4gc milligrams which number1 multiplied by two1 gives the invert sugar present4 ,the sample examined1 therefore1 had the following composition3 ,sucrose #aja4jj milligrams4 ,invert sugar #aci4df 0 ,dextrose #ai4ib 0 ------ ,sum #bfj4ch 0 ,on the other hand1 if the invert sugar be calculated from the quantity corresponding to the #bbe milligrams of copper corresponding to e1 the data will be very different from those given above4 ,in this instance of the levulose found corresponding to #bbe milligrams of copper1 viz41 #acc4hi1 #ec4ae milligrams are due to the inverted sucrose4 ,then the quantity due to the invert sugar at first present is #acc4hi - #ec4ae #hj4gd milligrams4 ,since half the weight of invert sugar is levulose1 the total weight of the invert sugar at first present is #afa4dh1 leaving only #h4ia milligrams due to added dextrose4 ,the difficulties in these calculations doubtless arise from the imperfect destruction of the levulose1 and from variations in the reducing action of sugars on copper salts in the presence of such large quantities of sodium chlorid4 #bej4 ,calculation from ,data obtained with ,copper ,carbonate4--,the wide variations observed in different methods of calculations in the preceding paragraph1 are due in part to the different degrees of oxidation exerted on alkaline copper tartrate by the dextrose and levulose4 ,better results are obtained by conducting the analytical work with ,ost's modification of ,soldaini's solution 7#abh74 ,the relative quantities of levulose and dextrose oxidized by this solution are almost identical1 and the calculations1 therefore1 result in nearly the same data1 whether made from the numbers obtained with the residual dextrose or from the levulose destroyed4 ,the method of applying this method is illustrated in the following calculation4 ,example4--,in a mixture of sucrose1 invert sugar1 and dextrose1 the quantities of copper obtained by using the copper carbonate solution were as follows3 ,copper obtained before inversion a #aej milligrams4 0 0 after 0 b #bej 0 0 0 0 destroying lev'e d #acg4e 0 0 equivalent to inverted sucrose b - a c #ajj 0 0 0 0 levulose b - d e #aab4e 0 #dd4j milligrams invert sugar4 a #aej milligrams ,cu #de4c 0 dextrose4 #db4e 0 levulose4 d #acg4e 0 0 #da4ee 0 dextrose4 c #ajj 0 0 #bi4e 0 invert sugar #bh4jbe sucrose4 e #aab4e 0 0 #ca4i 0 levulose4 #ad4ge milligrams of dextrose #dh4e milligrams ,cu4 #ad4ge 0 0 levulose #ea4e 0 0 #acg4e - #dh4e #hi4j milligrams ,cu due to dextrose present before inversion4 #hi4j milligrams ,cu #bg milligrams dextrose before inversion4 #aej4j - #hi4j 0 0 #fa4j 0 ,cu due to levulose present before inversion4 #fa4j 0 0 #ag4h 0 levulose before inversion4 #ag4h #b #ce4f milligrams invert sugar present before inversion4 #bg4j - #ag4h #i4b 0 dextrose 0 0 0 ,again3 #aab4e - #ea4e #fa4j milligrams ,cu due to levulose present before inversion4 #fa4j milligrams ,cu #ag4h milligrams levulose4 #ag4h 0 levulose indicate #ce4f milligrams invert sugar4 ,dextrose in invert sugar before inversion #ag4h milligrams4 ,total dextrose before inversion #bg4j milligrams4 ,dextrose above amount required for invert sugar #bg4j - #ag4h #i4b milligrams4 ,the respective quantities of the three sugars in the solution are1 therefore3 ,sucrose #bh4jbe milligrams4 ,invert sugar #ce4f 0 ,dextrose #i4b 0 ,the calculations made from the later data 7#bcd7 give almost the same results4 #bea4 ,winter's ,process4--,winter has proposed a method of separating dextrose and levulose in the presence of sucrose based on the selective precipitation produced on treating mixtures of these sugars in solution with ammoniacal lead acetate4#bjf ,the reagent is prepared immediately before use by adding ammonia to a solution of lead acetate until the opalescence which is at first produced just disappears4 ,the separation is based on the fact that the compound of sucrose with the reagent is easily soluble in water1 while the salts formed with levulose and dextrose are insoluble4 ,the separation of the sugars is accomplished as follows3 ,the ammoniacal lead acetate is added to the solution of the mixed sugars until no further precipitate is produced4 ,the precipitated matters are digested with a large excess of water and finally separated by filtration4 ,the sucrose is found in the filtrate in the form of a soluble lead compound1 from which it is liberated by treatment with carbon dioxid4 ,the lead carbonate produced is separated by filtration and the sucrose is estimated in an aliquot part of the filtrate by optical or chemical methods4 ,the precipitate containing the lead compounds of dextrose and levulose is washed free of sucrose1 suspended in water and saturated with carbon dioxid4 ,by this treatment the lead compound with dextrose is decomposed and1 on filtration1 the dextrose will be found in the filtrate1 while the lead compound of the levulose is retained upon the filter with the lead carbonate4 ,after well washing the precipitate1 it is again suspended in water and saturated with hydrogen sulfid4 ,by this treatment the lead levulosate compound is broken up and the levulose obtained1 on subsequent filtration1 in the filtrate4 ,the dextrose and levulose1 after separation as above described1 may be determined in aliquot parts of their respective filtrates by the usual gravimetric methods4 ,before determining the levulose the solution should be heated until all excess of hydrogen sulfid is expelled4 ,this method was used especially by ,winter in separating the various sugars obtained in the juices of sugar cane4 ,it has not been largely adopted as a laboratory method1 and on account of the time and trouble required for its conduct1 is not likely to assume any very great practical importance4 #beb4 ,separation of ,sugars by ,lead ,oxid4--,in addition to the combination with the earthy bases1 sugar forms well defined compounds with lead oxid4 ,one of these compounds is of such a nature as to have considerable analytical and technical value4 ,its composition and the method of preparing it have been pointed out by ,kassner4#bjg ,sucrose1 under conditions to be described1 forms with the lead oxid a diplumbic saccharate1 which separates in spheroidal crystals1 and has the composition corresponding to the formula ,c,h,o,pb #e;,h,o4 ,the precipitation takes place quantitively and should be conducted as follows3 ,the substance containing the sucrose1 which may be molasses1 sirups or concentrated juices1 is diluted with enough water to make a sirup which is not too viscous4 ,lead oxid suspended in water is stirred into the mass in such proportion as to give about two parts of oxid to one of the sugar4 ,the stirring is continued for some time until the oxid is thoroughly distributed throughout the mass and until it becomes thick by the commencement of the formation of the saccharate4 ,as soon as the mass is sufficiently thickened to prevent the remaining lead oxid from settling1 the stirring may be discontinued and the mixture is left for twenty-four hours1 at the end of which time the sucrose has all crystallized in the form of lead saccharate4 ,the crystals of lead saccharate can be separated by a centrifugal machine or by passing through a filter press1 and are thoroughly washed with cold water1 in which they are almost insoluble4 ,the washed crystals are beaten up with water into a thick paste and the lead separated as basic carbonate by carbon dioxid4 ,the sucrose is found in solution in the residual liquor and is concentrated and crystallized in the usual way4 ,reducing sugars have a stronger affinity for the lead oxid than the sucrose1 and this fact is made use of to effect a nearly complete separation when they are mixed together4 ,in order to secure this the lead oxid is added in the first place only in sufficient quantity to combine with the reducing sugars present1 the process being essentially that described above4 ,the reducing sugars which are precipitated as lead dextrosates1 lead levulosates1 etc41 are separated in the usual way by a centrifugal or a filter press1 and the resulting liquor1 which contains still nearly all the sucrose1 is subjected to a second precipitation by the addition of lead oxid4 ,the second precipitation obtained is almost pure diplumbic saccharate4 ,in the precipitation of the sugar which is contained in the beet molasses1 where only a trace or very little invert sugar is present1 the sucrose is almost quantitively separated1 and by the concentration of the residual liquor1 potash salts are easily obtained4 ,in this case1 after the decomposition of the lead saccharate by carbon dioxid1 the residual sugar solution is found entirely free of lead4 ,where invert sugar is present1 however1 in any considerable proportions1 it is found to exercise a slightly soluble influence on the lead saccharate1 and in this case a trace of lead may pass into solution4 ,for technical purposes1 this is afterwards separated by hydrosulfuric acid or the introduction of lime sulfid4 ,lead oxid is regenerated from the basic lead carbonate obtained by heating in retorts to a little above #bfj1 and the carbon dioxid evolved can also be used again in the technical process4 #bec4 ,commercial ,glucose and ,grape ,sugar4--,the commercial products obtained by the hydrolysis of starch are known in the trade as glucose or grape sugar4 ,the former term is applied to the thick sirup obtained by concentrating the products of a partial hydrolysis1 while the latter is applied to the solid semi-crystalline mass1 secured by continuing the hydrolyzing action until the intermediate products are almost completely changed to dextrose4 ,in this country the starch employed is obtained almost exclusively from maize1 and the hydrolyzing agent used is sulfuric acid4#bjh ,the products of conversion in glucose are chiefly dextrins and dextrose with some maltose1 and in grape sugar almost entirely dextrose4 ,when diastase is substituted for an acid1 as the hydrolytic agent1 maltose is the chief product1 the ferment having no power of producing dextrose4 ,in the glucose of ,japan1 known as midzu ame dextrin and maltose are the chief constituents4#bji ,commercial glucose is used chiefly by confectioners for manufacturing table sirups and for adulterating honey and molasses4 ,commercial grape sugar is chiefly employed by brewers as a substitute for barley and other grains4 ,in ,europe1 the starch which is converted into glucose1 is derived principally from potatoes4 ,the method employed in conversion1 whether an acid or diastatic action1 is revealed not only by the nature of the product1 but also by the composition of its ash4 ,in the case of diastatic conversion the ash of the sample will contain only a trace of sulfates1 no chlorin1 and be strongly alkaline1 while the product of conversion with sulfuric acid will give an ash rich in sulfates with a little lime and be less strongly alkaline4 ,the process of manufacture in this country consists in treating the starch1 beaten to a cream with water1 with sulfuric acid1 usually under pressure1 until the product shows no blue color with iodin4 ,the excess of acid is removed with marble dust1 the sirup separated by filtration1 whitened by bleaching with sulfurous acid or by passing it through bone-black and evaporated to the proper consistence in a vacuum4 ,the solid sugar1 consisting mostly of dextrose1 is made in the same manner1 save that the heating with the acid is continued until the dextrin and maltose are changed into maltose4 ,the product is either obtained in its ordinary hydrated form or by a special method of crystallization secured as bright anhydrous crystals4 ,solutions of dextrose1 when first made1 show birotation1 but attain their normal gyrodynatic state on standing for twenty-four hours in the cold1 or immediately on boiling4 #bed4 ,methods ,of ,separation4--,the accurate determination of the quantities of the several optically active bodies formed in commercial glucose is not possible by any of the methods now known4 ,approximately accurate data may be secured by a large number of processes1 and these are based chiefly on the ascertainment of the rotation and reducing power of the mixed sugars1 the subsequent removal of the dextrose and maltose by fermentation or oxidation and the final polarization of the residue4 ,the difficulties which attend these processes are alike in all cases4 ,fermentation may not entirely remove the reducing sugars or may act slightly on the dextrin4 ,in like manner the oxidation of these sugars by metallic salts may not entirely decompose them1 may leave an optically active residue1 or may affect the optical activity of the residual dextrin4 ,the quantitive methods of separating these sugars by means of phenylhydrazin1 lead salts or earthy bases have not been developed into reliable and applicable laboratory processes4 ,at the present time the analyst must be contented with processes confessedly imperfect1 but which1 with proper precautions1 yield data which are nearly correct4 ,the leading methods depending on fermentation and oxidation combined with polarimetric observations will be described in the subjoined paragraphs4 #bee4 ,fermentation ,method4--,this process is based on the assumption that1 under certain conditions1 dextrose and maltose may be removed from a solution and the dextrin be left unchanged4 ,in practice1 approximately accurate results are obtained by this method1 although the assumed conditions are not strictly realized4 ,in the prosecution of this method the polarimetric reading of the mixed sugars is made1 and the maltose and dextrose removed therefrom by fermentation with compressed yeast4 ,the residual dextrins are determined by the polariscope on the assumption that their average gyrodynat is #aic4 ,in the calculation of the quantities of dextrose and maltose their gyrodynats are fixed at #ec and #ach respectively4 ,the total quantity of reducing sugar is determined by the usual processes4 ,the relative reducing powers of dextrose and maltose are represented by #ajj and #fb respectively4 ,the calculations are made by the following formulas3#baj ,r reducing sugars as dextrose d dextrose m maltose d dextrin ,p total polarization 7calculated as apparent gyrodynat7 ,p rotation after fermentation 7calculated as apparent gyrodynat74 ,whence ,r d #j4fbm 7#a7 ,p #ec;d #achm #afc;d 7#b7 ,p #aic;d 7#c7 ,from these three equations the values of d1 m1 and d are readily calculated3 ,example3 ,to find d and m3 ,subtract 7#c7 from 7#b7 ,p #ec;d #accm #aic;d ,p #aic;d -------------------------------------- ,p - ,p #ec;d #achm 7#d7 ,multiply 7#a7 by #ec and subtract from 7#d7 ,p - ,p #ec;d #achm #ec,r #ec;d #cb4hfm ---------------------------------------- --- ,p - ,p - #ec,r #aje4adm 7#e7 ,p - ,p - #ec,r ,whence m ------------------ 7#f7 #aje4ad d ,r - #j4fbm 7#g7 ,p d ---- 7#h7 #aic ,sidersky assigns the values a,d #ach4c and a,d #aid4h to maltose and dextrin respectively in the above formulas4#baa ,illustration3 ,in the examination of a sample #bf4jdh grams of midzu ame in #ajj cubic centimeters were polarized in a #bjj millimeter tube and the following data were obtained3 ,polarization of sample in angular degrees #fi4jf1 which is equal to an apparent gyrodynat of #acb4f3 ,total reducing sugar as dextrose #cc4cc per cent3 ,polarization in angular degrees after fermentation #cj4hd a,d #ei4b4 ,substituting these values in the several equations gives the following numbers3 7#a7 #j4cccc d #j4fbm 7#b7 #acb4f #ec;d #achm #aic;d 7#c7 #ei4b #aic;d 7#d7 #gc4d #ec;d #achm 7#e7 #ee4gd #aje4adm 7#f7 m #j4ecja #ec4ja per cent4 7#g7 d #cccc - #cbhf #j4jjdg #jj4dg per cent4 7#h7 d #ei4b #aic #j4cjfg #cj4fg 0 0 ,summary3 ,sample of midzu ame3 ,percentage of dextrin #cj4fg per cent4 0 0 maltose #ec4ja 0 0 0 0 dextrose #jj4dg 0 0 0 0 water #ad4fa 0 0 0 0 ash #jj4ca 0 0 ----- ,sum #ii4jg 0 0 ,undetermined #j4ic 0 0 ,for polarization the lamplight shadow polariscope employed for sugar may be used1 and the degrees of the sugar 7ventzke7 scale converted into angular degrees by multiplying by #j4cdfg4 ,the process of fermentation is conducted as described in the paragraph given further on1 relating to the determination of lactose in the presence of sucrose4 #bef4 ,the ,oxidation ,method4--,the removal of the reducing sugars may be accomplished by oxidation instead of fermentation4 ,the process of analysis is in all respects similar to that described in the foregoing paragraph1 substituting oxidation for fermentation4#bab ,for the oxidizing agent mercuric cyanid is preferred1 and it is conveniently prepared by dissolving #abj grams of mercuric cyanid and an equal quantity of sodium hydroxid in water mixing the solutions and completing the volume to one liter4 ,if a precipitate be formed in mixing the solutions it should be removed by filtering through asbestos4 ,for the polarization1 ten grams of the sugars in #ajj cubic centimeters is a convenient quantity4 ,ten cubic centimeters of this solution are placed in a flask of water marked at fifty cubic centimeters1 a sufficient quantity of the mercuric cyanid added to remain in slight excess after the oxidation is finished 7from twenty to twenty-five cubic centimeters7 and the mixture heated to the boiling point for three minutes4 ,the alkali1 after cooling1 is neutralized with strong hydrochloric acid and the passing from alkalinity to acidity will be indicated by a discharge of the brown color which is produced by heating with the alkaline mercuric cyanid4 ,the heating with the mercury salt should be conducted in a well ventilated fume chamber4 ,the calculation of the results is conducted by means of the formulas given in the preceding paragraph4 ,in the original paper describing this method1 it was stated that its accuracy depended on the complete oxidation of the reducing sugar in a manner leaving no optically active products1 and on the inactivity of the reagents used in respect to the dextrin present4 ,these two conditions are not rigidly fulfilled1 as is shown by ,wilson4#bac ,according to his data maltose leaves an optically active residue1 which gives a somewhat greater right hand rotation than is compensated for by the diminished rotation of the dextrin4 ,wilson1 however1 confesses that the dextrin used contained reducing sugars1 which would not be the case had it been prepared by the process of treating it with alkaline mercuric cyanid as above indicated4 ,upon the whole1 the oxidation of the reducing sugar by a mercury salt gives results which1 while not strictly accurate1 are probably as reliable as those afforded by fermentation4 ,the author has attempted to supplant both the oxidation and fermentation methods by removing the reducing sugars with a precipitating reagent1 such as phenylhydrazin1 but the methods are not sufficiently developed for publication4 #beg4 ,removal of ,dextrose by ,copper ,acetate4--,maercker first called attention to the fact that ,barfoed's reagent 7one part copper acetate in fifteen parts of water1 and #bjj cubic centimeters of this solution mixed with five cubic centimeters of thirty-eight per cent4 acetic acid7 reacts readily with dextrose1 while it is indifferent to maltose and dextrins4 ,sieben's method of removing dextrose is based on this fact4#bad ,it is found that under certain conditions pure maltose does not reduce either the acidified or neutral solution of copper acetate1 while dextrose or a mixture of dextrose and maltose does so readily4 ,it is also shown that the fermentation residue under suitable conditions acts like maltose4 ,maltose solutions reduce the reagent after boiling four minutes while at #dj-de they have no effect even after standing four days4 ,the amount of copper deposited by dextrose1 under the latter conditions1 is found to depend to a certain extent on the amount of free acetic acid present1 and as the solutions of copper acetate always contain varying quantities of acetic acid which cannot be removed without decomposition and precipitation of basic salt1 the use of an absolutely neutral solution is impracticable4 ,the reagent prepared according to ,barfoed's directions is almost saturated1 but a half normal solution is preferable4 ,sieben proposes two solutions3 ,i1 containing #ae4hf grams copper and #j4ef gram acetic anhydrid per liter2 ,,ii1 containing #ae4hf grams copper and three grams acetic anhydrid per liter4 ,the reduction of the dextrose is secured by placing #ajj cubic centimeters of the solution in a bottle1 adding the sugar solution1 stoppering and keeping in a water-bath at #dj-de two or three days4 ,an aliquot portion is then drawn off and the residual copper precipitated by boiling with forty-five cubic centimeters of the alkali solution of the fehling reagent and forty cubic centimeters of one per cent dextrose solution1 filtered and weighed as usual4 ,the results show that either solution can be used1 and that standing for two days at #de is sufficient4 ,one hundred cubic centimeters of the copper solution are mixed with ten cubic centimeters of the sugar solution containing from two-tenths to five-tenths gram of dextrose1 as this dilution gives the best results4 ,no reduction is found to have taken place when solutions containing five-tenths gram maltose or five-tenths gram fermentation residue are used4 ,the data can not be compiled in the form of a table similar to ,allihn's1 as it is impossible to obtain a solution of uniform acidity each time1 and the solution will have to be standardized by means of a known pure dextrose solution and the result obtained with the unknown sugar solution properly diluted compared with this4 ,this method of ,sieben's has never been practiced to any extent in analytical separations and can not1 therefore1 be strongly recommended without additional experience4 #beh4 ,removal of ,dextrin by ,alcohol4--,by reason of its less solubility1 dextrin can be removed from a solution containing also dextrose and maltose by precipitation with alcohol4 ,it is impracticable1 however1 to secure always that degree of alcoholic concentration which will cause the coagulation of all the dextrins without attacking the concomitant reducing sugars4 ,in this laboratory it has been found impossible to prepare a dextrin by alcoholic precipitation1 which did not contain bodies capable of oxidizing alkaline copper solutions4 ,the solution containing the dextrin is brought to a sirupy consistence by evaporation and treated with about ten volumes of ninety per cent alcohol4 ,after thorough mixing1 the precipitated dextrin is collected on a filter and well washed with alcohol of the strength noted4 ,it is then dried and weighed4 ,if weaker solutions of dextrin are used1 the alcohol must be of correspondingly greater strength4 ,in the filtrate the residual maltose and dextrose may be separated and determined by the chemical and optical methods already described4 ,,carbohydrates ,,in ,,milk4 #bei4 ,the ,copper ,tartrate ,method4--,the lactose in milk is readily estimated by the gravimetric copper method described in paragraph #adc4 ,before the application of the process the casein and fat of the milk should be removed by an appropriate precipitant1 and an aliquot part of the filtrate1 diluted to contain about one per cent of milk sugar1 used for the determination4 ,the clarification is very conveniently secured by copper sulfate or acetic acid1 as described in the next paragraph4 ,a proper correction should be made for the volume occupied by the precipitate and1 for general purposes1 with whole milk of fair quality this volume may be assumed to be five per cent4 ,one hundred grams of milk will give a precipitate occupying approximately five cubic centimeters4 ,in the analytical process1 to twenty cubic centimeters of milk1 diluted with water to eighty1 is added a ten per cent solution of acetic acid1 until a clear whey is shown after standing a few minutes1 when the volume is completed to #ajj cubic centimeters with water1 and the whole1 after thorough shaking1 thrown on a filter4 ,an aliquot part of the filtrate is neutralized with sodium carbonate and used for the lactose determination4 ,this solution contains approximately one per cent of lactose4 ,in a convenient part of it the lactose is determined and the quantity calculated for the whole4 ,this quantity represents the total lactose in the twenty cubic centimeters of milk used4 ,the weight of the milk is found by multiplying twenty by its specific gravity4 ,from this number the percentage of lactose is easily found4 ,in this process the milk is clarified by the removal of its casein and fat4 ,other albuminoids remain in solution and while these doubtless disturb the subsequent determination of lactose1 any attempt at their removal would be equally as disadvantageous4 ,the volume of the precipitate formed by good1 whole milk when the process is conducted as above described1 is about one cubic centimeter1 for which a corresponding correction is readily made4 #bfj4 ,the ,official ,method4--,the alkaline copper method of determining lactose1 adopted by the ,association of ,official ,agricultural ,chemists1 is essentially the procedure proposed by ,soxhlet4#bae ,dilute twenty-five cubic centimeters of the milk1 held in a half liter flask1 with #djj cubic centimeters of water and add ten cubic centimeters of a solution of copper sulfate of the strength given for ,soxhlet's modification of ,fehling's solution1 page #abi2 add about seven and a half cubic centimeters of a solution of potassium hydroxid of such strength that one volume of it is just sufficient to completely precipitate the copper as hydroxid from one volume of the solution of copper sulfate4 ,in place of a solution of potassium hydroxid of this strength eight and a half cubic centimeters of a half normal solution of sodium hydroxid may be used4 ,after the addition of the alkali solution the mixture must still have an acid reaction and contain copper in solution4 ,fill the flask to the mark1 shake and filter through a dry filter4 ,place fifty cubic centimeters of the mixed copper reagent in a beaker and heat to the boiling point4 ,while boiling briskly1 add #ajj cubic centimeters of the lactose solution1 prepared as directed above1 and boil for six minutes4 ,filter immediately and determine the amount of copper reduced by one of the methods already given1 pages #adi-aee4 ,obtain the weight of lactose equivalent to the weight of copper found from the table on page #afc4 #bfa4 ,the ,copper ,cyanid ,process4--,it has been found by ,blyth that the copper cyanid process of ,gerrard gives practically the same results in the determination of sugar in milk as are obtained by optical methods4#baf ,the milk for this purpose is clarified1 by precipitating the casein with acetic acid in the following manner3 ,twenty-five cubic centimeters of milk are diluted with an equal volume of distilled water1 and strong acetic acid added until the casein begins to separate4 ,the liquid is heated to boiling and1 while hot1 centrifugated in any convenient machine4 ,the supernatant liquid obtained is separated by filtration and the solid matter thrown upon the filter and well washed with hot water4 ,the filtrate and washings are cooled and completed to a volume of #ajj cubic centimeters4 ,this liquid is of about the proper dilution for use with the copper cyanid reagent4 ,the percentage of sugar determined by this reagent agrees well with that obtained by the optical method1 when no other sugars than lactose are present4 ,if there be a notable difference in the results of the two methods other sugars must be looked for4 ,the presence of dextrin may be determined by testing a few drops of the clear liquor with iodin1 which1 in the presence of dextrin1 gives a reddish color4 ,other sugars are determined by obtaining their osazones4 ,for this purpose the filtrate obtained as above should be concentrated until the volume is about thirty cubic centimeters4 ,any solid matter which separates during the evaporation is removed by filtration4 ,the osazones are precipitated in the manner described in paragraph #adg4 ,on cooling1 the almost solid crystalline mass obtained is placed on a filter1 washed with a little cold water1 the crystals then pressed between blotting paper and dried at a temperature of #ajj4 ,the dry osazones obtained are dissolved in boiling absolute alcohol1 of which just sufficient is used to obtain complete solution4 ,the alcoholic solution is set aside for twelve hours and the separation of a crystalline product after that time shows that dextrose or invert sugar is present4 ,milk sugar alone gives no precipitate but only a slight amorphous deposit4 ,the lactosazone is precipitated by adding a little water to the hot alcoholic solution and the crystals thus obtained should be dissolved in boiling absolute alcohol and reprecipitated by the addition of water at least three times in order to secure them pure4 ,the osazones are identified by their melting points1 paragraph #agb4 ,the first part of this method does not appear to have any advantage over the optical process by double dilution 7p4 #bgh71 and requires more time4 #bfb4 ,sugars in ,evaporated ,milks4--,in addition to the lactose normally present in evaporated milks the analyst will1 in most cases1 find large quantities of sucrose4 ,the latter sugar is added as a preservative and condiment4 ,by reason of the ease with which sucrose is hydrolyzed1 evaporated milk containing it may have also some invert sugar among its contents4 ,a method of examination is desirable1 therefore1 which will secure the determination of lactose1 sucrose and invert sugar in mixtures4 ,the probability of the development of galactose and dextrose during the evaporation and conservation of the sample1 is not great4 ,the best method of conducting this work is the one developed by ,bigelow and ,mc,elroy4#bag ,the principle on which the method is based rests on the fact that in certain conditions1 easily supplied1 the sucrose and invert sugar present in a sample may be entirely removed by fermentation and the residual lactose secured in an unchanged condition4 ,the lactose is finally estimated by one of the methods already described4 ,the details of the process follow3 ,on opening a package of evaporated milk1 its entire contents are transferred to a dish and well mixed4 ,several portions of about twenty-five grams each are placed in flasks marked at #ajj cubic centimeters4 ,to each of the flasks enough water is added to bring all the sugars into solution and normal rotation is made certain by boiling4 ,after cooling1 the contents of the flasks are clarified by mercuric iodid in acetic acid solution4 ,the clarifying reagent is prepared by dissolving fifty-three grams of potassium iodid1 twenty-two grams of mercuric chlorid1 and thirty-two cubic centimeters of strongest acetic acid in water1 mixing the solutions and completing the volume to one liter4 ,the clarification is aided by the use of alumina cream 7#hd74 ,the flask is filled to the mark1 and the contents well shaken and poured on a filter4 ,after rejecting the first portion of the filtrate the residue is polarized in the usual manner4 ,two or more separate portions of the sample are dissolved in water in flasks of the size mentioned1 heated to #ee1 half a cake of compressed yeast added to each and the temperature kept at #ee for five hours4 ,the residue in each flask is treated as above described1 the mercuric solution being added before cooling to prevent the fermentative action of the yeast1 and the polarization noted4 ,by this treatment the sucrose is completely inverted1 while the lactose is not affected4 ,the percentage of sucrose is calculated by the formulas given in paragraph #id1 using the factor #adb4f4 ,at the temperature noted the yeast exercises no fermentative1 but only a diastatic action4 ,in each case the volume of the precipitated milk solids is determined by the double dilution method1 and the proper correction made 7p4 #bgh74 ,the lactose remaining is determined by chemical or optical methods1 but it is necessary1 in all cases where invert sugar is supposed to be present1 to determine the total reducing sugars in the original sample as lactose4 ,if the quantity thus determined and the amount of sucrose found as above are sufficient to produce the rotation observed in the first polarization1 it is evident that no invert sugar is present4 ,when the polarization observed is less than is equivalent to the quantity of sugar found1 invert sugar is present1 which tends to diminish the rotation produced by the other sugars4 ,in this case it is necessary to remove both the sucrose and invert sugar by a process of fermentation1 which will leave the lactose unchanged4 ,this is accomplished by conducting the fermentation in the presence of potassium fluorid1 which prevents the development of the lactic ferments4 ,for this purpose #cej grams of the evaporated milk are dissolved in water and the solution boiled to secure the normal rotation of the lactose4 ,after cooling to #hj1 the casein is thrown down by adding a solution containing about four grams of glacial phosphoric acid and keeping the temperature at #hj for about fifteen minutes4 ,after cooling to room temperature1 the volume is completed to one liter with water1 well shaken and poured onto a filter4 ,an aliquot part of the filtrate is nearly neutralized with a noted volume of potassium hydroxid4 ,enough water is added to make up1 with the volume of potassium hydroxid used1 the total space occupied by the precipitated solid1 corresponding to that part of the filtrate1 and if necessary1 refilter4 ,the volume occupied by the precipitated solids is easily determined by polarization and double dilution4 ,the filtrate1 obtained from the process described above1 is placed in portions of #ajj cubic centimeters each in #bjj cubic centimeter flasks with about twenty milligrams of potassium fluorid in solution1 and half a cake of compressed yeast4 ,the yeast is broken up and evenly distributed1 and the fermentation is allowed to proceed for ten days at a temperature of from #be to #cj4 ,at the end of this time experience has shown that all of the sucrose and invert sugar has disappeared1 but the lactose remains intact4 ,the flasks are filled to the mark with water and the lactose determined by chemical or optical methods4 ,by comparing the data obtained from the estimation of the total reducing sugars before fermentation or inversion and the estimation of the lactose after fermentation1 the quantity of invert sugar is easily calculated4 ,the experience of this laboratory shows that invert sugar is rarely present in evaporated milks1 which is an indication that the sucrose added thereto does not generally suffer hydrolysis4 ,the mean percentage of added sucrose found in evaporated milks is about forty4 ,,separation ,,and ,,determination ,,of ,,starch4 #bfc4 ,occurrence4--,many bodies containing starch are presented for the consideration of the agricultural analyst4 ,first in importance are the cereals1 closely followed by the starchy root crops4 ,many spices and other condiments also contain starchy matters4 ,in the sap of some plants1 for instance sorghum1 at certain seasons1 considerable quantities of starch occur4 ,in the analysis of cereals and other feeding stuffs1 it has been the usual custom to make no separate determination of starch1 but to put together all soluble carbohydrates and estimate their percentage by subtracting from #ajj the sum of the percentages of the other constituents of the sample4 ,this aggregated mass has been known as nitrogen-free extract4 ,recent advances in methods of investigation render it advisable to determine the starch and pentosan carbohydrates separately and to leave among the undetermined bodies the other unclassed substances1 chiefly of a carbohydrate nature1 soluble in boiling dilute acid and alkali4 #bfd4 ,separation of ,starch4--,starch being insoluble in its natural state1 it is impossible to separate it from the other insoluble matters of plants by any known process4 ,in bringing it into solution it undergoes certain changes of an unknown nature1 but tending to produce a dextrinoid body4 ,nevertheless1 in order to procure the starch in a state of purity suited to analytical processes1 it becomes necessary to dissolve the starch from the other insoluble bodies that naturally accompany it4 ,as has been shown in preceding paragraphs1 there are only two methods of securing the solution of starch which fully meet the conditions of accurate analysis4 ,these are the methods depending on the use of diastatic ferments and on the employment of heat and pressure in the presence of water4 ,these two processes have been described in considerable detail in paragraphs #agi-aha4 ,it is important1 in starch determinations1 to remove from the sample the sugar and other substances soluble in water and also the oils1 when present in large quantities1 before subjecting it to the processes for rendering the starch soluble4 #bfe4 ,desiccation of ,amyliferous ,bodies4--,the removal of sugars and oils is best secured in amyliferous substances after they are deprived of their moisture4 ,as has already been suggested1 the desiccation should be commenced at a low temperature1 not above #fj1 and continued at that point until the chief part of the water has escaped4 ,the operation may be conducted in one of the ways already described 7pp4 #ab-bg74 ,there is great difference of opinion among analysts in respect of the degree of temperature to which the sample should be finally subjected1 but for the purposes here in view1 it will not be found necessary to go above #aje4 ,before beginning the operation the sample should be as finely divided as possible1 and at its end the dried residue should be ground and passed through a sieve of half a millimeter mesh4 #bff4 ,indirect ,method of ,determining3 ,water in ,starch4--,it is claimed by ,block#bah that it is necessary to dry starch at #afj in order to get complete dehydration4 ,wet starch as deposited with its maximum content of water has nine molecules thereof1 viz41 ,c,h,o #i;,h,o4 ,ordinary commercial starch has about eighteen per cent of water with a formula of ,c,h,o #b;,h,o4 ,the percentage of water may be determined by ,block's feculometer or ,block's dose-fcule4 ,the first apparatus determines the percentage of anhydrous starch by volume1 and the second by weight4 ,block's assumption that starch can absorb only fifty per cent of its weight of water is the basis of the determination4 ,a noted weight of starch is rubbed up with water until saturated1 the water poured off1 the starch weighed1 dried on blotting paper until it gives off no more moisture and again weighed4 ,half of the lost weight is water1 from which the original per cent of water can be calculated4 ,this at best seems to be a rough approximation and not suited to rigorous scientific determination4 #bfg4 ,removal of ,oil and ,sugar4--,the dried1 finely powdered sample1 obtained as described above1 is placed in any convenient extractor 7#cc-dc7 and the oil or fat it contains removed by the usual solvents4 ,for ordinary purposes1 even with cereals1 this preliminary extraction of the oil is not necessary1 but it becomes so with oily seeds containing starch4 ,the sugar is subsequently removed by extraction with eighty per cent alcohol and the residue is then ready for the extraction of the starch4 ,in most cases the extraction with alcohol will be found sufficient4 ,in some bodies1 for instance the sweet potato 7batata71 the quantity of sugar present is quite large1 and generally some of it is found4 ,if not present in appreciable amount1 the alcohol extraction may also be omitted4 ,the sample having been prepared as indicated1 the starch may be brought into solution by one of the methods described in paragraphs #agi-aha1 preference being given to the aqueous digestion in an autoclave4 ,the dissolved starch is washed out of the insoluble residue and determined by optical or chemical methods #ahf-aid4 #bfh4 ,preparation of ,diastase for ,starch ,solution4--,the methods of preparing malt extract for use in starch analysis have been described in paragraph #agi4 ,if a purer form of diastase is desired it may be prepared by following the directions given by ,long and ,baker4#bai ,digest #bjj grams of ground malt for twenty-four hours with three parts of twenty per cent alcohol4 ,separate the extract by filtration and to the filtrate add about one and a half liters of ninety-three per cent alcohol and stir vigorously4 ,after the precipitate has subsided the supernatant alcohol is removed by a syphon1 the precipitate is brought onto a filter and washed with alcohol of a strength gradually increasing to anhydrous1 and finally with anhydrous ether4 ,the diastase is dried in a vacuum over sulfuric acid and finally reduced to a fine powder before using4 ,thus prepared1 it varies in appearance from a white to a slightly brownish powder4 ,made at different times and from separate portions of malt1 it may show great differences in hydrolytic power4 #bfi4 ,estimation of ,starch in ,potatoes by ,specific ,gravity4--,a roughly approximate determination of the quantity of starch in potatoes can be made by determining their specific gravity4 ,since the specific gravity of pure starch is #a4fe1 it follows that the richer a potato is in starch the higher will be its specific gravity4 ,the specific weight of substances like potatoes is conveniently determined by suspending them in water by a fine thread attached to the upper hook of a balance pan4 ,there may be a variation of the percentage of other constituents in potatoes as well as of starch1 and therefore the data obtained from the following table can only be correct on the assumption that the starch is the only variable4 ,in practice1 errors amounting to as much as two per cent may be easily made1 and therefore the method is useful only for agronomic and commercial and not for scientific purposes4 ,the method is especially useful in the selection of potatoes of high starch content for planting4 ,the table is constructed on the weight in grams in pure water of #ajjjj grams of potatoes and the corresponding per cents of dry matter and starch are given4 ,it is not always convenient to use exactly #ajjjj grams of potatoes for the determination1 but the calculation for any given weight is easy4#bbj ,example4--,let the weight of a potato in air be #aei grams1 and its weight in water #ad4h grams4 ,then the weight of #ajjjj grams of potatoes of like nature in water would be found from the equation #aei3 #ajjjj #ad4h3 x4 ,whence x #ica nearly4 ,in the table the nearest figure to #ica is #icj1 corresponding to #bd4f per cent of dry matter and #ah4h per cent of starch4 ,when the number found is half way between the numbers given in the table the mean of the data above and below can be taken4 ,in other positions a proper interpolation can be made if desired but for practical purposes the data corresponding to the nearest number can be used4 ,,table ,,for ,,calculating ,,starch ,,in ,,potatoes ,,from ,,specific ,,gravity4 #ajjjj grams of potatoes weigh in ,per cent ,per cent water4 dry matter4 starch4 ,grams4 #gej #ai4i #ad4a #gfj #bj4a #ad4c #ggj #bj4c #ad4e #ghj #bj4g #ad4i #gij #bj4i #ae4a #hjj #ba4b #ae4d #haj #ba4d #ae4f #hbj #ba4f #ae4h #hcj #bb4j #af4b #hdj #bb4b #af4d #hej #bb4d #af4f #hfj #bb4g #af4i #hgj #bb4i #ag4a #hhj #bc4a #ag4c #hij #bc4e #ag4g #ijj #bc4g #ag4i #iaj #bd4j #ah4b #ibj #bd4b #ah4d #icj #bd4f #ah4h #idj #bd4h #ai4j #iej #be4j #ai4b #ifj #be4b #ai4d #igj #be4e #ai4g #ihj #be4i #bj4a #iij #bf4a #bj4c #ajjj #bf4c #bj4e #ajaj #bf4e #bj4g #ajbj #bf4i #ba4a #ajcj #bg4b #ba4d #ajdj #bg4d #ba4f #ajej #bg4f #ba4h #ajfj #bh4j #bb4b #ajgj #bh4c #bb4e #ajhj #bh4e #bb4g #ajij #bh4g #bb4i #aajj #bi4a #bc4c #aaaj #bi4c #bc4e #aabj #bi4e #bc4g #aacj #bi4h #bd4j #aadj #cj4b #bd4d #aaej #cj4d #bd4f #aafj #cj4f #bd4h #aagj #ca4j #be4j #aahj #ca4c #be4e #aaij #ca4e #be4g #abjj #ca4g #be4i #abaj #cb4a #bf4c #abbj #cb4c #bf4e #abcj #cb4e #bf4g #abdj #cc4j #bg4b #abej #cc4b #bg4d #abfj #cc4d #bg4f #abgj #cc4f #bg4h #abhj #cd4a #bh4c #abij #cd4c #bh4e #acjj #cd4e #bh4g #acaj #cd4i #bi4a #acbj #ce4a #bi4c #accj #ce4d #bi4f #acdj #ce4h #cj4j #acej #cf4j #cj4b #acfj #cf4b #cj4d #acgj #cf4f #cj4h #bgj4 ,constitution of ,cellulose4--,the group of bodies known as cellulose comprises many members of essentially the same chemical constitution but of varying properties4 ,the centesimal composition of pure cellulose is shown by the following numbers3 ,carbon1 #dd4b per cent ,hydrogen1 #f4c 0 0 ,oxygen1 #di4e 0 0 corresponding to the formula ,c,h,h4 ,according to the view of ,cross and ,bevan1 cellulose conforms in respect of its ultimate constitutional groups to the general features of the simple carbohydrates1 but differs from them by reason of a special molecular configuration resulting in a suppression of the activity of constituent groups in certain respects1 and an increase in activity of others4#bba #bga4 ,fiber and ,cellulose4--,the carbohydrates of a plant insoluble in water are not composed exclusively of starch4 ,there are1 in addition to starch1 pentosan fibers yielding pentose sugars on hydrolysis and furfuraldehyd on distillation with a strong acid4 ,the quantitive methods for estimating the pentosan bodies are given in paragraphs #aej-aeg4 ,the method to be preferred is that of ,krug 7#aee74 ,in the estimation of cattlefoods and of plant substances in general the residue insoluble in dilute boiling acid and alkali is called crude or indigestible fiber4 ,the principle on which the determination depends rests on the assumption that all the protein1 starch and other digestible carbohydrates will be removed from the sample by successive digestion at a boiling temperature with acid and alkali solutions of a given strength4 ,it is evident that the complex body obtained by the treatment outlined above is not in any sense a definite chemical compound1 but it may be considered as being composed partly of cellulose4 #bgb4 ,official ,method of ,determining ,crude ,fiber4--,the method of estimating crude fiber1 adopted by the ,association of ,official ,agricultural ,chemists1 is as follows3#bbb ,extract two grams of the substance with ordinary ether1 at least almost completely1 or use the residue from the determination of the ether extract4 ,to this residue1 in a half liter flask1 add #bjj cubic centimeters of boiling #a4be per cent sulfuric acid2 connect the flask with an inverted condenser1 the tube of which passes only a short distance beyond the rubber stopper into the flask4 ,boil at once1 and continue the boiling for thirty minutes4 ,a blast of air conducted into the flask may serve to reduce the frothing of the liquid4 ,filter1 wash thoroughly with boiling water until the washings are no longer acid1 rinse the substance back into the same flask with #bjj cubic centimeters of a boiling #a4be per cent solution of sodium hydroxid1 free or nearly free of sodium carbonate1 boil at once and continue the boiling for thirty minutes in the same manner as directed above for the treatment with acid4 ,filter into a gooch1 and wash with boiling water until the washings are neutral1 dry at #aaj1 weigh and incinerate completely4 ,the loss of weight is crude fiber4 ,the filter used for the first filtration may be linen1 one of the forms of glass wool or asbestos filters1 or any other form that secures clear and reasonably rapid filtration4 ,the solutions of sulfuric acid and sodium hydroxid are to be made up of the specified strength1 determined accurately by titration and not merely from specific gravity4 ,the experience of this laboratory has shown that results practically identical with those got as above1 are obtained by conducting the digestions in hard glass beakers covered with watch glasses4 ,the ease of manipulation in the modification of the process just mentioned is a sufficient justification for its use4 #bgc4 ,separation of ,cellulose4--,hoppe-,seyler observed that cellulose1 when melted with the alkalies at a temperature as high as #bjj1 was not sensibly attacked4#bbc ,lange has based a process for determining cellulose on this observation4#bbd ,the process1 as improved by him1 is carried out as follows3 ,from five to ten grams of the substance are moistened with water and placed in a porcelain dish with about three times their weight of caustic alkali free of nitrates and about twenty cubic centimeters of water4 ,the porcelain dish should be deep and crucible shaped and should be placed in an oil-bath1 the temperature of which is easily controlled4 ,the contents of the dish are stirred with the thermometer bulb until all foaming ceases and the temperature of the mixture is then kept at from #age to #ahj for an hour4 ,after the melt has cooled to #hj about seventy-five cubic centimeters of hot water are added to bring it into solution and it is then allowed to cool4 ,the solution is acidified with sulfuric and placed in large centrifugal tubes4 ,after being made slightly alkaline with soda lye1 the tubes are subjected to continued energetic centrifugal action until the cellulose is separated4 ,the supernatant liquid can be nearly all poured off and the separated cellulose is broken up1 treated with hot water and again separated by centrifugal action4 ,the cellulose is finally collected upon the asbestos felt1 washed with hot water1 alcohol and ether1 dried and weighed4 ,with a little practice it is possible to complete the separation of cellulose in two and one-half hours4 #bgd4 ,solubility of ,cellulose4--,cellulose resembles starch in its general insolubility1 but1 unlike starch1 it may be dissolved in some reagents and afterwards precipitated practically unchanged or in a state of hydration4 ,one of the simplest solvents of cellulose is zinc chlorid in concentrated aqueous solution4 ,the solution is accomplished with the aid of heat1 adding one part by weight of cotton to six parts of zinc chlorid dissolved in ten parts of water4 ,a homogeneous sirup is obtained by this process1 which is used in the arts for making the carbon filaments of incandescent electric lamps4 ,in preparing the thread of cellulose1 the solution1 obtained as described above1 is allowed to flow1 in a fine stream1 into alcohol1 whereby a cellulose hydrate is precipitated1 which is freed from zinc hydroxid by digesting in hydrochloric acid4 ,hydrochloric acid may be substituted for water in preparing the reagent above noted1 whereby a solvent is secured which acts upon cellulose readily in the cold4 ,a solution of ammoniacal cupric oxid is one of the best solvents for cellulose4 ,the solution should contain from ten to fifteen per cent of ammonia and from two to two and a half of cupric oxid4 ,in the preparation of this reagent1 ammonium chlorid is added to a solution of cupric salt and then sodium hydroxid in just sufficient quantity to precipitate all of the copper as hydroxid4 ,the precipitate is well washed on a linen filter1 squeezed as dry as possible and dissolved in ammonia of #j4ib specific gravity4 ,the cellulose is readily precipitated from the solution in cuprammonium by the addition of alcohol1 sodium chlorid1 sugar1 or other dehydrating agents4 ,solutions of cellulose are used in the arts for many purposes4#bbe #bge4 ,qualitive ,reactions for ,detecting ,cellulose4--,cellulose may be identified by its resistance to the action of oxidizing agents1 to the halogens and to alkaline solutions4 ,it is further recognized by the sirupy or gelatinous solutions it forms with the solvents mentioned above4 ,the cellulose hydrates precipitated from solutions have in some instances the property of forming a blue color with iodin4 ,a characteristic reaction of cellulose is secured as follows3 ,to a saturated solution of zinc hydrochlorate1 of #b4jj specific gravity1 are added six parts by weight of potassium iodid dissolved in ten parts of water and this solution is saturated with iodin4 ,cellulose treated with this reagent is at once stained a deep blue violet color4#bbf ,for the characteristics of cellulose occurring in wood the researches of ,lindsey may be consulted4#bbg #bgf4 ,more ,rarely ,occurring ,carbohydrates4--,it is not possible here to give more space to the rarer forms of carbohydrates1 to which the attention of the agricultural analyst may be called4 ,nearly a hundred kinds of sugars alone have been detected in the plant world4 ,for descriptions of the properties of these bodies and the methods of their detection and determination1 the standard works on carbohydrates may be consulted4#bbh ,,authorities ,,cited ,,in ,,part ,,third4 #agj ,vines2 ,physiology of ,plants4 ,ngeli2 ,beitrge zur nheren ,kenntniss der ,strkegruppe4 #aga ,bulletin #e1 ,department of ,agriculture1 ,division of ,chemistry1 pp4 #aia et seq43 ,bulletin #be1 ,new ,hampshire ,experiment ,station4 #agb ,spencer2 ,handbook for ,sugar ,manufacturers1 p4 #ca4 #agc ,vid4 op4 cit4 supra1 pp4 #ajb1 #ajh4 #agd ,journal of the ,american ,chemical ,society1 ,vol4 #af1 p4 #fgg4 #age ,botanical ,gazette1 ,vol4 #ab1 ,no4 #c4 #agf ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,tome #ac1 p4 #acc4 #agg ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #d1 p4 #cha4 #agh ,spencer's ,handbook for ,sugar ,manufacturers1 pp4 #cj et seq4 #agi ,bulletin de l',association des ,chimistes de ,sucrerie et de ,distillerie1 ,tome #ac1 p4 #bib4 #ahj ,vid4 op4 cit4 supra1 ,tome #b1 p4 #cfi4 #aha ,dosage du ,sucre ,cristallisable dans la ,betterave1 pp4 #aag et seq43 ,journal of the ,american ,chemical ,society1 ,vol4 #af1 p4 #bff4 #ahb ,neue ,zeitschrift fr ,rbenzucker-,industrie4 ,band #c1 ,s4 #cdb2 ,band #ad1 ,s4 #bhf3 ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahgf1 ,s4 #fib3 ,dingler's ,polytechnisches ,journal1 ,band #bcb1 ,s4 #dfa4 #ahc ,sidersky3 ,trait d' ,analyse des ,matires ,sucres1 p4 #cjd4 #ahd ,neue ,zeitschrift fr ,rbenzucker-,industrie1 ,band #ad1 ,s4 #bhf4 #ahe ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 ,band #cb1 ,s4 #hfa4 #ahf ,spencer's ,handbook for ,sugar ,manufacturers1 p4 #db4 #ahg ,bulletin ,no4 #d of the ,chemical ,society of ,washington1 pp4 #bb1 et seq4 #ahh ,vid4 op4 et loc4 cit4 #g4 #ahi ,chemiker-,zeitung1 ,band #ai1 ,s4 #ahcj4 #aij ,vid4 op cit4 supra1 ,s4 #aghd4 #aia ,vid4 op4 cit4 supra1 ,s4 #ahbi4 #aib ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahie1 ,s4 #hdd4 #aic ,journal des ,fabricants de ,sucre1 #ahie1 ,no4 #cc4 #aid ,journal of the ,american ,chemical ,society1 ,vol4 #b1 p4 #chg3 ,agricultural ,science1 ,feb4 #ahib4 #aie ,american ,chemical ,journal1 ,vol4 #ac1 p4 #bd4 #aif ,tucker2 ,manual of ,sugar ,analysis1 p4 #bhg3 ,wiechmann2 ,sugar ,analysis1 p4 #ea4 #aig ,sidersky2 vid4 op4 cit41 #ad1 p4 #aig4 #aih ,journal of the ,american ,chemical ,society1 ,vol4 #ah1 p4 #ha3 ,allen2 ,commercial ,organic ,analysis1 ,vol4 #a1 p4 #bia4 #aii ,handbuch der ,physiologisch- und ,pathologisch-,chemischen ,analyse1 ,s4 #bhf4 #bjj ,khne und ,chittenden2 ,american ,chemical ,journal1 ,vol4 #f1 p4 #de4 #bja ,vid4 op4 cit4 supra1 p4 #bhi4 #bjb ,analyst1 ,vol4 #ac1 p4 #fd4 #bjc ,journal ,american ,chemical ,society1 ,vol4 #ah1 p4 #dch4 #bjd ,school of ,mines ,quarterly1 ,vols4 #aa and #ab4 ,in a later method 7,school of ,mines ,quarterly1 ,vol4 #ac1 ,no4 #c7 ,wiechman describes the separation of the sugars by one polariscopic and two gravimetric determinations1 one before and one after inversion4 ,the polariscopic examination is made in a ten per cent solution at a temperature of #bj4 ,the gyrodynats of sucrose1 dextrose and levulose at the temperature mentioned are fixed at #ff4e1 #ec4e and -#ha4i respectively4 ,the gravimetric determinations are conducted according to the methods already described4 ,in the formulas for calculating the results a represents sucrose1 b reducing sugars1 x the dextrose1 y the levulose1 and d the observed polarization expressed in degrees angular measure4 ,the gyrodynats of sucrose1 dextrose and levulose divided by #ajj are represented by s1 d and l4 ,the calculations are made from the following formulas3 7as xd7 - yl p4 7as xd7 p yl4 xd p yl - as4 p yl - as x -----------------4 d ,in this calculation the gyrodynat of levulose is about ten degrees lower than that of most authorities4 #bje ,vid4 op4 cit41 #bc1 ,band #bd1 ,s4 #hfi4 #bjf ,vid4 op4 cit4 supra1 #ahhh1 ,s4 #ghb4 #bjg ,neue ,zeitschrift fr ,rbenzucker-,industrie1 ,band #ce1 ,s4 #aff4 #bjh ,journal of the ,american ,chemical ,society1 ,vol4 #b1 p4 #cii3 ,science1 ,oct4 #a1 #ahha3 ,proceedings ,american ,association for the ,advancement of ,science1 #ahha1 p4 #fa3 ,sugar ,cane1 ,vol4 #ac1 p4 #ecc1 pp4 #fa-ff4 #bji ,wiley and ,mc,elroy2 ,agricultural ,science1 ,vol4 #f1 p4 #eg4 #baj ,chemical ,news1 ,vol4 #df1 p4 #age4 #baa ,vid4 op4 cit1 #ad1 p4 #ceb4 #bab ,vid4 op4 et loc4 cit41 #da4 #bac ,vid4 op4 cit41 #da1 ,vol4 #fe1 p4 #afi4 #bad ,zeitschrift des ,vereins fr die ,rbenzucker-,industrie1 #ahhd1 ,s4 #hed4 #bae ,bulletin #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #fj4 #baf ,the ,analyst1 ,vol4 #bj1 p4 #aba4 #bag ,journal ,american ,chemical ,society1 ,vol4 #ae1 p4 #ffh4 #bah ,comptes rendus1 ,tome #aah1 p4 #adg4 #bai ,journal of the ,chemical ,society1 ,transactions1 #ahie1 p4 #gce4 #bbj ,die agrikultur-chemische ,versuchsstation1 ,halle1 a_/,s41 ,s4 #aad4 #bba ,cellulose1 p4 #gg4 #bbb ,vid4 op4 cit41 #df1 p4 #fc4 #bbc ,zeitschrift fr physiologische ,chemie1 ,band #ac1 ,s4 #hd4 #bbd ,zeitschrift fr angewandte ,chemie1 #ahie1 ,s4 #efa4 #bbe ,vid4 op4 cit41 #eb1 pp4 #h et seq4 #bbf ,vid4 op4 cit4 supra1 p4 #ae4 #bbg ,composition of ,wood1 ,agricultural ,science1 ,vol4 #g1 pp4 #di1 #ig and #afa4 #bbh ,tollens2 ,handbuch der ,kohlenhydrate3 von ,lippmann2 ,chemie der ,zuckerarten4 ,,part ,,fourth4 ,,fats ,,and ,,oils4 #bgg4 ,nomenclature4--,the terms fat and oil are often used interchangeably and it is difficult in all cases to limit definitely their application4 ,the consistence of the substance at usual room temperatures may be regarded as a point of demarcation4 ,the term fat1 in this sense1 is applied to glycerids which are solid or semi solid1 and oil to those which are quite or approximately liquid4 ,a further classification is found in the origin of the glycerids1 and this gives rise to the groups known as animal or vegetable fats and oils4 ,in this manual1 in harmony with the practices mentioned above1 the term fat will be used to designate an animal or vegetable glycerid which is solid1 and the term oil one which is liquid at common room temperature1 viz41 about #bj4 ,there are few animal oils1 and few vegetable fats when judged by this standard1 and it therefore happens that the term oil is almost synonymous with vegetable glycerid and fat with a glycerid of animal origin4 ,nearly related to the fats and oils is the group of bodies known as resins and waxes4 ,this group of bodies1 however1 can be distinguished from the fats and oils by chemical characteristics4 ,the waxes are ethers formed by the union of fatty acids and alcohols of the ethane1 and perhaps also of the ethylene series4#bbi ,this chemical difference is not easily expressed and the terms themselves often add confusion to the meaning1 as for instance1 japan wax is composed mostly of fats1 and sperm oil is essentially a wax4 #bgh4 ,composition4--,fats and oils are composed chiefly of salts produced by the combination of the complex base glycerol with the fat acids4 ,certain glycerids1 as the lecithins1 contain also phosphorus in organic combinations1 nitrogen1 and possibly other inorganic constituents in organic forms4 ,by the action of alkalies the glycerids are easily decomposed1 the acid combining with the inorganic base and the glycerol becoming free4 ,the salts thus produced form the soaps of commerce and the freed base1 when collected and purified1 is the glycerol of the trade4 ,when waxes are decomposed by alkalies1 fatty acids and alcohols of the ethane series are produced4 ,the natural glycerids formed from glycerol1 which is a trihydric 7triatomic7 alcohol1 are found in the neutral state composed of three molecules of the acid1 united with one of the base4 ,if ,r represent the radicle of the fat acid the general formula for the chemical process by which the salt is produced is3 ,glycerol4 ,acid4 ,salt4 ,water4 ,o4,h ,o4,r ,c,h,o4,h #c,r4,,oh ,c,h,o4,r #c;,h,o4 ,o4,h ,o4,r ,the resulting salts are called triglycerids or neutral glycyl ethers4#bcj ,in natural animal and vegetable products1 only the neutral salts are found1 the mono- and diglycerids resulting from artificial synthesis4 ,for this reason the prefix tri is not necessarily used in designating the natural glycerids1 stearin1 for instance1 meaning the same as tristearin4 #bgi4 ,principal ,glycerids4--,the most important glycerids which the analyst will find are the following3 ,olein1 ,c,h,o7,o4,c,h,o74 ,stearin1 ,c,h,o7,o4,c,h74 ,palmitin1 ,c,h,o7,o4,c,h,o74 ,linolein1 ,c,h,o7,o4,c,h,o74 ,butyrin1 ,c,h,o7,o4,c,h,o74 ,olein is the chief constituent of most oils2 palmitin is found in palm oil and many other natural glycerids2 stearin is a leading constituent of the fats of beeves and sheep1 and butyrin is a characteristic constituent of butter1 which owes its flavor largely to this glycerid and its nearly related concomitants4 #bhj4 ,extraction of ,oils and ,fats4--,preparatory to a physical and chemical study of the fats and oils is their separation from the other organic matters with which they may be associated4 ,in the case of animal tissues this is usually accomplished by the application of heat4 ,the operation known as rendering may be conducted in many different ways4 ,for laboratory purposes1 the animal tissues holding the fat are placed in a convenient dish and a degree of heat applied which will liquify all the fat particles and free them from their investing membranes4 ,the temperature employed should be as low as possible to secure the desired effect1 but fats can be subjected for some time to a heat of a little more than #ajj1 without danger of decomposition4 ,the direct heat of a lamp1 however1 should not be applied1 since it is difficult to avoid too high a temperature at the point of contact of the flame and dish4 ,the dry heat of an air-bath or rendering in an autoclave or by steam is preferable4 ,the residual animal matter is subjected to pressure and the combined liquid fat freed from foreign matters by filtering through a jacket filter1 which is kept at a temperature above the solidifying point of the contents4 ,on a large scale1 as in rendering lard1 the fat is separated by steam in closed vats which are strong enough to withstand the steam pressure employed4 ,for analytical purposes it is best to extract the fat from animal tissues in the manner described1 since the action of solvents is slow on fat particles enveloped in their containing membranes1 and the fats1 when extracted1 are liable to be contaminated with extraneous matters4 ,in dried and ground flesh meal1 however1 the fat may be extracted with the usual solvents4 ,for the quantitive determination of fat in bones or flesh1 the sample1 as finely divided as possible1 is thoroughly dried1 and the fat separated from an aliquot finely powdered portion by extraction with chloroform1 ether1 or petroleum4 ,the action of anhydrous ether on dried and powdered animal matters is apparently a continuous one4 ,dormeyer has shown that even after an extraction of several months additional matter goes into solution4#bca ,the fat in such cases can be determined by saponification with alcoholic potash and the estimation of the free fatty acids produced4 ,from vegetable substances1 such as seeds1 the fat is extracted either by pressure or by the use of solvents4 ,for quantitive purposes1 only solvents are employed4 ,the dry1 finely ground material is exhausted with anhydrous ether or petroleum spirit1 in one of the convenient forms of apparatus already described 7#cc-dc74 ,in very oily seeds great difficulty is experienced in securing a fine state of subdivision suited to complete extraction4 ,in such cases it is advisable to conduct the process in two stages4 ,in the first stage the material1 in coarse powder1 is exhausted as far as possible and the percentage of oil determined4 ,the residue is then easily reduced to a fine powder1 in an aliquot part of which the remaining oil is determined in the usual way4 ,illustration3 ,,fig4 #gi4--,,oil ,,press4 ,in securing oils for physical and chemical examination both pressure and solution may be employed4 ,the purest oils are secured by pressure at a low temperature4 ,to obtain anything like a good extraction some sort of hydraulic pressure must be used4 ,in this laboratory a press is employed in which the first pressure is secured by a screw and this is supplemented by hydraulic pressure in which glycerol is the transmitting liquid4 ,the construction of the press is shown in the accompanying figure4 ,the whole press is warmed to nearly #ajj4 ,the hot finely ground oily material1 enclosed in a cloth bag1 is placed in the perforated cylinder and compressed as firmly as possible by turning with the hands the wheel shown at the top of the figure4 ,the final pressure is secured by the screw shown at the bottom of the figure whereby a piston is driven into a cylinder containing glycerol4 ,the degree of pressure obtained is equal to #cjj atmospheres4 ,even with the best laboratory hydraulic pressure not more than two-thirds of the total oil contents of oleaginous seeds can be secured and the process is totally inapplicable to securing the oil from tissues when it exists in quantities of less than ten per cent4 ,to get practically all of the oil the best method is to extract with carefully distilled petroleum of low boiling point4 ,in the preparation of this reagent the petroleum ether of commerce1 containing bodies boiling at temperatures of from #ce to #hj1 is repeatedly fractioned by distillation until a product is obtained which boils at from #de to #fj4 ,the distillation of this material is conducted in a large flask heated with steam1 furnished with a column containing a number of separatory funnels and connected with an appropriate condenser4 ,the distillate is secured in a bottle packed with broken ice1 as shown in ,fig4 #hj4 ,a thermometer suspended in the vapor of the petroleum serves to regulate the process4 ,too much care to avoid accidents cannot be exercised in this operation4 ,not only must steam be used in heating1 but all flame and fire must be rigidly excluded from the room in which the distillation takes place1 and the doors leading to other rooms where gas jets may be burning must be kept closed4 ,in the beginning of the process1 as much as possible of the petroleum boiling under #de must be removed and rejected4 ,the distillation is then continued until the temperature rises above #fj4 ,the parts of the distillate saved between these temperatures are redistilled under similar conditions4 ,other portions of the petroleum1 boiling at other temperatures1 may be secured in the same way4 ,the products may be in a measure freed of unpleasant odors by redistilling them from a mixture with lard4 ,when used for quantitive purposes the petroleum ether must leave no residue when evaporated at #ajj4 ,illustration3 ,,fig4 #hj4--;,,apparatus ,,for ,,fractional ,,distillation ,,of ,,petroleum ,,ether4 #bha4 ,freeing ,extracted ,oils from ,petroleum4--,the petroleum ether which is used for extracting oils tends to give them an unpleasant odor and flavor and its entire separation is a matter of some difficulty4 ,the greater part of the solvent may be recovered as described in paragraph #dc4 ,heating the extracted oil for several hours in thin layers1 will remove the last traces of the solvent1 but affords opportunity for oxidation1 especially in the case of drying oils4 ,an effective means of driving off the last traces of petroleum is to cause a current of dry carbon dioxid to pass through the sample contained in a cylinder and heated to a temperature of from #he to #ij4 ,the atmosphere of the inert gas will preserve the oil from oxidation and the sample will1 as a rule1 be found free of the petroleum odor after about ten hours treatment4 ,ethyl ether or chloroform may be used instead of petroleum1 but these solvents act on other matters than the glycerids1 and the extract is therefore liable to be contaminated with more impurities than when the petroleum ether is employed4 ,other solvents for fats are carbon tetrachlorid1 carbon disulfid1 and benzene4 ,in general1 petroleum ether should be employed in preference to other solvents1 except in the case of castor oil1 which is difficultly soluble in both petroleum and petroleum ethers4 #bhb4 ,freeing ,fats ,of ,moisture4--,any excess of water in glycerids will accumulate at the bottom of the liquid sample and can be removed by decanting the fat or separating it from the oil by any other convenient method4 ,the warm oil may be almost entirely freed of any residual moisture by passing it through a dry filter paper in a jacket funnel kept at a high temperature4 ,a section showing the construction of such a funnel with a folded filter paper in place1 is shown in ,fig4 #ha4 ,the final drying1 when great exactness is required1 is accomplished in a vacuum1 or in an atmosphere of inert gas1 or in the cold in an exsiccator over sulfuric acid4 ,in drying1 it is well to expose the hot oil as little as possible to the action of the air4 ,wherever convenient1 it should be protected from oxidation by some inert gas or a vacuum4 #bhc4 ,sampling for ,analysis4--,it is a matter of some difficulty to secure a representative sample of a fat or oil for analytical purposes4 ,the moisture in a fat is apt to be unevenly distributed1 and the sampling is to be accomplished in a manner to secure the greatest possible uniformity4 ,when the quantity of material is of considerable quantity a trier may be used which will remove a cylindrical or partly cylindrical mass from the whole length or depth4 ,by securing several subsamples of this kind1 and well mixing them1 an average sample of the whole mass may be secured4 ,where the fat is found in different casks or packages samples should be drawn from each as described above4 ,the subsamples are mixed together in weights corresponding to the different casks from which they are taken and the mass obtained by this mixture divided into three equal portions4 ,two of these parts are melted in a dish at a temperature not exceeding #fj1 with constant stirring1 and when fully liquid the third part is added4 ,as a rule1 the liquid fat retains enough heat to melt the added quantity4 ,as soon as the mixed fats begin to grow pasty the mass is vigorously stirred to secure an intimate mixture of the water and other foreign bodies4#bcb ,illustration3 ,,fig4 #ha4--,,section ,,showing ,,construction ,,of ,a ,,funnel ,,for ,,hot ,,filtration4 ,in the case of butter fat the official chemists recommend that subsamples be drawn from all parts of the package until about #ejj grams are secured4 ,the portions thus drawn are to be perfectly melted in a closed vessel at as low a temperature as possible1 and when melted the whole is to be shaken violently for some minutes till the mass is homogeneous1 and sufficiently solidified to prevent the separation of the water and fat4 ,a portion is then poured into the vessel from which it is to be weighed for analysis1 and this should nearly or quite fill it4 ,this sample should be kept in a cold place till analyzed4#bcc #bhd4 ,estimation of ,water4--,in the official method for butter fat1 which may be applied to all kinds1 about two grams are dried to constant weight1 at the temperature of boiling water1 in a dish with flat bottom1 having a surface of at least twenty square centimeters4 ,the use of clean dry sand or asbestos is admissible1 and is necessary if a dish with round bottom be employed4 ,in the method recommended by ,benedikt1 about five grams of the sampled fat are placed in a small flask or beaker and dried at #ajj with occasional stirring to bring the water to the surface4 ,according to the method of ,sonnenschein1 the sample is placed in a flask carrying a cork1 with an arrangement of glass tubes1 whereby a current of dry air may be aspirated over the fat during the process of drying4 ,when the flask is properly fitted its weight is taken1 the fat put in and reweighed to get the exact amount4 ,the fat is better preserved by aspirating carbon dioxid instead of air4#bcd ,the moisture may also be readily determined by drying on pumice stone1 as described in paragraph #bf4 ,in this case it is well to conduct the desiccation in vacuum or in an inert atmosphere to prevent oxidation4 ,,physical ,,properties ,,of ,,fats4 #bhe4 ,specific ,gravity4--,the specific gravity of an oil is readily determined by a westphal balance 7#ec71 by a spindle1 by a sprengel tube1 or more accurately by a pyknometer4 ,the general principles governing the conduct of the work have already been given 7#dh-ei74 ,the methods described for determining the density of sugar solutions are essentially the same as those used for oils1 but it is to be remembered that oils and fats are lighter than water and the graduation of the sinkers for the hydrostatic balance1 and the spindles for direct determination must be for such lighter liquids4 ,the necessity of determining the density of a fat at a temperature above its melting point is manifest1 and for this reason the use of the pyknometer at a high temperature 7#dj to #ajj7 is to be preferred to all the other processes1 in the case of fats which are solid at temperatures below #be4 ,illustration3 ,,fig4 #hb4--;,,balance ,,and ,,westphal ,,sinker4 ,when great delicacy of manipulation is desired1 combined with rapid work1 an analytical balance and westphal sinker may be used conjointly4#bce ,in this case it is well to have two or three sinkers graduated for #bj1 #be1 and #dj1 respectively4 ,nearly all fats1 when melted and cooled to #dj1 remain in a liquid state long enough to determine their density4 ,the sinkers are provided with delicate thermometers1 and the temperature1 which at the beginning is a little above the degree at which the sinker is graduated1 is allowed to fall to just that degree1 when the equilibrium is secured in the usual manner4 ,the sinker is conveniently made to displace just five grams of distilled water at the temperature of graduation1 but it is evident that a round number is not necessary1 but only convenient for calculation4 #bhf4 ,expression of ,specific ,gravity4--,much confusion arises in the study of data of densities because the temperatures at which the determinations are made are not expressed4 ,the absolute specific gravity would be a comparison of the weight of the object at #d1 with water at the same temperature4 ,it is evident that such determinations are not always convenient1 and for this reason the determinations of density are usually made at other temperatures4 ,in the case of a sinker1 which at #ce displaces exactly five grams of water1 the following statements may be made3 ,one cubic centimeter of water at #ce weighs #j4iidjih gram4 ,the volume of a sinker displacing five grams of water at that temperature is therefore #e4jbig cubic centimeters4 ,this volume of water at #d weighs #e4jbig grams4 ,in a given case the sinker placed in an oil at #ce is found to displace a weight equal to #d4egbe grams corresponding to a specific gravity of #ce_/ce #j4iade4 ,from the foregoing data the following tabular summary is constructed3 ,weight of #e4jbhg cubic centimeters of oil at #ce1 #d4egbe grams4 0 0 #e4jbig 0 0 0 water at #ce1 #e4jjjj 0 0 0 #e4jbig 0 0 0 0 0 #d1 #e4jbig 0 ,relative weight of oil at #ce1 to water at #ce1 #j4iade grams4 0 0 0 0 0 #ce1 0 0 0 #d1 #j4ijib 0 #bhg4 ,coefficient of ,expansion of ,oils4--,oils and fats of every kind have almost the same coefficient of expansion with increasing temperature4 ,the coefficient of expansion is usually calculated by the formula ,d - ,d ---------------- 7t - t7,d in which represents the coefficient of expansion1 ,d the density at the lowest temperature1 ,d the density at the highest temperature1 t the lowest1 and t the highest temperatures4 ,in the investigations made by ,crampton it was shown that the formula would be more accurate1 written as follows3#bcf ,d - ,d --------------------------- 7t - t7 ,d ,d --------------- #b ,the absolute densities can be calculated from the formula ,k1 in which represents the coefficient of absolute expansion1 the apparent coefficient of expansions observed in glass vessels1 and ,k the cubical coefficient of expansion of the glass vessel4 ,the mean absolute coefficient of expansion for fats and oils1 for #a as determined by experiment1 is almost exactly #j4jjjh1 and the apparent coefficient of expansion nearly #j4jjjgg4bcg #bhh4 ,standard of ,comparison4--,in expressing specific gravities it is advisable to refer them always to water at #d4 ,the temperature at which the observation is made should also be given4 ,thus the expression of the specific gravity of lard1 determined at different temperatures1 is made as follows3 #ae4e #dj d ------ #j4iaaha2 d ----- #j4hifgi2 #d #d #ajj and d ---- #j4heiig1 #d indicating the relative weights of the sample under examination at #ae4e1 #dj1 and #ajj1 respectively1 to water at #d4 #bhi4 ,densities of ,common ,fats and ,oils4--,it is convenient to have at hand some of the data representing the densities of common fats and oils1 and the following numbers are from results of determinations made in this laboratory3#bch #ae4e #dj #ajj ,temperature4 d -----4 d ---4 d ----4 #d #d #d ,leaf lard #j4iaaha #j4hifgi #j4heiig ,lard stearin #j4ijife #j4hiddc #j4hegej ,oleostearin #j4ijgad #j4hibbc #j4heegb ,crude cottonseed oil #j4ibjaf #j4ijdhf #j4hfgci ,summer 0 0 #j4ibjee #j4ijdif #j4hffha ,winter 0 0 #j4ibagi #j4ijfab #j4hfggd ,refined 0 0 #j4ibaej #j4ijegc #j4hfgad ,compound lard 0 #j4iaeae #j4ijjjj #j4hfbhi ,olive oil #j4iaeje #j4hiife #j4hfafh #bij4 ,melting ,point4--,the temperature at which fats become sensibly liquid is a physical characteristic of some importance4 ,unfortunately1 the line of demarcation between the solid and liquid states of this class of bodies is not very clear4 ,few of them pass per saltum from one state to the other4 ,in most cases there is a gradual transition1 which1 between its initial and final points1 may show a difference of several degrees in temperature4 ,it has been noted1 further1 that fats recently melted behave differently from those which have been solid for several hours4 ,for this reason it is advisable1 in preparing glycerids for the determination of their melting point1 to fuse them the day before the examination is to be made4 ,the temperature at which a glycerid passes from a liquid to a solid state is usually higher than that at which it resumes its solid form4 ,if1 however1 the change of temperature could be made with extreme slowness1 exposing the sample for many hours at near its critical temperature1 these differences would be much less marked4 ,many methods have been devised for determining the melting point of fats1 and none has been found that is satisfactory in every respect4 ,in some cases the moment at which fluidity occurs is assumed to be that one when the small sample loses its opalescence and becomes clear4 ,in other cases the moment of fluidity is determined by the change of shape of the sample or by observing the common phenomena presented by a liquid body4 ,in still other cases1 the point at which the sample becomes fluid is determined by the automatic completion of an electric circuit1 which is indicated by the ringing of a bell4 ,this latter process has been found very misleading in our experience4 ,only a few of the proposed methods seem to demand attention here1 and some of those1 depending on the visible liquefaction of a small quantity of the fat or based on the physical property1 possessed by all liquids when removed from external stress1 of assuming a spheroidal state will be described4 ,other methods which may demand attention in any particular case may be found in the works cited4#bci #bia4 ,determination in a ,capillary ,tube4--,a capillary tube is dipped into the melted fat and when filled one end of the tube is sealed in the lamp and it is then put aside in a cool place for twenty-four hours4 ,at the end of this time the tube is tied to the bulb of a delicate thermometer the length used or filled with fat being of the same length as the thermometer bulb4 ,the thermometer and attached fat are placed in water1 oil1 or other transparent media1 and gently warmed until the capillary column of fat becomes transparent4 ,at this moment the thermometric reading is made and entered as the melting point of the fat4 ,in comparative determinations the same length of time should be observed in heating1 otherwise discordant results will be obtained4 ,as in all other methods1 the resulting members are comparative and not absolute points of fusion1 and the data secured by two observers on the same sample may not agree1 if different methods of preparing the fat and different rates of fusion have been employed4 ,illustration3 ,,fig4 #hc4--,,melting ,,point ,,tubes4 ,several modifications of the method just described are practiced1 and perhaps with advantage in some cases4 ,in one of these a small particle of the fat is solidified in a bulb blown on a small tube1 as indicated in ,fig4 #hc1 tube a4 ,the tube1 in an upright position1 is heated in a convenient bath until the particle of fat just begins to run assuming soon the position shown in tube b4 ,this temperature is determined by a thermometer1 whose bulb is kept in contact with the part of the observation tube containing the fat particle4 ,the rise of temperature is continued until the fat collected at the bottom of the bulb is entirely transparent4 ,this is called the point of complete fusion4#bdj ,pohl covers the bulb of a thermometer with a thin film of fat1 and the instrument is then fixed in a test tube1 in such a way as not to touch the bottom1 and the film of fat warmed by the air-bath until it fuses and collects in a droplet at the end of the thermometer bulb4#bda ,carr has modified this process by inserting the thermometer in a round flask in such a way that the bulb of the thermometer is as nearly as possible in the center4 ,by this device the heating through the intervening air is more regular and more readily controlled4#bdb ,a particle of fat placed on the surface of clean mercury will melt when the mercury is raised to the proper temperature4 ,where larger quantities of the fat are employed1 a small shot or pellet of mercury may be placed upon the surface and the whole warmed until the metal sinks4 ,of the above noted methods1 the analyst will find some form of capillary tube or the use of a film of the fat on the bulb of a thermometer the most satisfactory4#bdc ,hehner and ,angell have modified the sinking point method by increasing the size of the sinker without a corresponding increase in weight4 ,this is accomplished by blowing a small pear-shaped float1 nearly one centimeter in diameter and about two long4 ,the stem of the pear is drawn out and broken off1 and while the bulb is still warm1 the open end of the stem is held in mercury1 and a small quantity of this substance1 sufficient in amount to cause the float to sink slowly through a melted fat1 is introduced into the bulb of the apparatus and the stem sealed4 ,the whole bulb should displace about one cubic centimeter of liquid and weigh1 after filling with mercury1 about three and four-tenths grams4 ,in conducting the experiment about thirty grams of the dry melted fat are placed in a large test tube and cooled by immersing the tube in water at a temperature of #ae4 ,the tube containing the solidified fat is placed in a bath of cold water and the sinker is placed in the center of the surface of the fat4 ,the bath is slowly heated until the float disappears4 ,the temperature of the bath is read just as the bulb part of the float disappears4 ,the method is recommended especially by the authors for butter fat investigations4#bdd #bih4 ,melting ,point ,determined by the ,spheroidal ,state4--,the method described by the author1 depending on the assumption of the spheroidal state of a particle of liquid removed from all external stress1 has been found quite satisfactory in this laboratory1 and has been adopted by the official chemists4#bde ,in the preparation of the apparatus there are required3 7a7 a piece of ice floating in distilled water that has been recently boiled1 and 7b7 a mixture of alcohol and water of the same specific gravity as the fat to be examined4 ,this is prepared by boiling distilled water and ninety-five per cent alcohol for a few minutes to remove the gases which they may hold in solution4 ,while still hot1 the water is poured into the test tube described below until it is nearly half full4 ,the test tube is then nearly filled with the hot alcohol1 which is carefully poured down the side of the inclined tube to avoid too much mixing4 ,if the alcohol is not added until the water has cooled1 the mixture will contain so many air bubbles as to be unfit for use4 ,these bubbles will gather on the disk of fat as the temperature rises and finally force it to the top4 ,illustration3 ,,fig4 #hd4--;,,apparatus ,,for ,,the ,,determination ,,of ,,melting ,,point4 ,the apparatus for determining the melting point is shown in ,fig4 #hd1 and consists of 7a7 an accurate thermometer reading easily tenths of a degree2 7b7 a cathetometer for reading the thermometer 7but this may be done with an eye-glass if held steadily and properly adjusted72 7c7 a thermometer2 7d7 a tall beaker1 thirty-five centimeters high and ten in diameter2 7e7 a test tube thirty centimeters long and three and a half in diameter2 7f7 a stand for supporting the apparatus2 7g7 some method of stirring the water in the beaker 7for example1 a blowing bulb of rubber1 and a bent glass tube extending to near the bottom of the beaker74 ,the disks of fat are prepared as follows3 ,the melted and filtered fat is allowed to fall from a dropping tube from a height of about twenty cubic centimeters on a smooth piece of ice floating in recently boiled distilled water4 ,the disks thus formed are from one to one and a half centimeters in diameter and weigh about #bjj milligrams4 ,by pressing the ice under the water the disks are made to float on the surface1 whence they are easily removed with a steel spatula1 which should be cooled in the ice water before using4 ,they should be prepared a day or at least a few hours before using4 ,the test tube containing the alcohol and water is placed in a tall beaker1 containing water and ice1 until cold4 ,the disk of fat is then dropped into the tube from the spatula1 and at once sinks until it reaches a part of the tube where the density of the alcohol-water is exactly equivalent to its own4 ,here it remains at rest and free from the action of any force save that inherent in its own molecules4 ,the delicate thermometer is placed in the test tube and lowered until the bulb is just above the disk4 ,in order to secure an even temperature in all parts of the alcohol mixture in the vicinity of the disk1 the thermometer is gently moved from time to time in a circularly pendulous manner4 ,the disk having been placed in position1 the water in the beaker is slowly heated1 and kept constantly stirred by means of the blowing apparatus already described4 ,when the temperature of the alcohol-water mixture rises to about #f below the melting point1 the disk of fat begins to shrivel1 and gradually rolls up into an irregular mass4 ,the thermometer is now lowered until the fat particle is even with the center of the bulb4 ,the bulb of the thermometer should be small1 so as to indicate only the temperature of the mixture near the fat4 ,a gentle rotatory movement from time to time should be given to the thermometer bulb4 ,the rise of temperature should be so regulated that the last #b of increment require about ten minutes4 ,the mass of fat gradually approaches the form of a sphere1 and when it is sensibly so the reading of the thermometer is to be made4 ,as soon as the temperature is taken the test tube is removed from the bath and placed again in the cooler4 ,a second tube1 containing alcohol and water1 is at once placed in the bath4 ,the test tube 7ice water having been used as a cooler7 is of low enough temperature to cool the bath sufficiently4 ,after the first determination1 which should be only a trial1 the temperature of the bath should be so regulated as to reach a maximum of about #a4e above the melting point of the fat under examination4 ,the edge of the disk should not be allowed to touch the sides of the tube4 ,this accident rarely happens1 but in case it should take place1 and the disk adhere to the sides of the tube1 a new trial should be made4 ,triplicate determinations should be made1 and the second and third results should show a near agreement4 ,example4--,melting point of sample of butter3 ,degrees4 ,first trial #cc4ae ,second trial #cc4je ,third trial #cc4jj ,the fatty acids1 being soluble in alcohol1 cannot be treated as the ordinary glycerids4 ,but even those glycerids which are slightly soluble in alcohol may be subjected to the above treatment without fear of experiencing any grave disturbance of the fusing points4 #bic4 ,solidifying ,point4--,the temperature at which a fat shows incipient solidification is usually lower than the point of fusion4 ,the same difficulties are encountered in determining the temperature of solidification as are presented in observing the true melting point4 ,the passage from a transparent liquid to an opaque solid is gradual1 showing all the phases of turbidity from beginning opalescence to complete opacity4 ,the best the analyst can do is to determine1 as accurately as possible1 the temperature at which the more solid glycerids of the mixture begin to form definite crystals4 ,this point is affected to a marked degree by the element of time4 ,a fat cooled just below its melting point will become solid after hours1 or days1 whereas it could be quickly cooled far below that temperature and still be limpid4 ,the methods of observation are the same for the glycerids and fatty acids1 and the general process of determination is sufficiently set forth in the following description of the method as used in this laboratory4#bdf ,illustration3 ,,fig4 #he4--;,,apparatus ,,for ,,determining ,,crystallizing ,,point4 ,the melted fat or fat acid is placed in a test tube contained in a large bottle1 which serves as a jacket to protect the tube from sudden or violent changes of temperature4 ,the efficiency of the jacket may be increased by exhausting the air therefrom1 as in the apparatus for determining the heat of bromination1 hereafter described4 ,a very delicate thermometer1 graduated in tenths of a degree1 and having a long bulb1 is employed4 ,by means of the reading glass1 the reading can be made in twentieths of a degree4 ,the arrangement of the apparatus is shown in ,fig4 #he4 ,the test tube is nearly filled with the melted matter4 ,the bottom of the jacket should be gently warmed to prevent a too rapid congelation in the bottom of the test tube containing the melted fat1 and the tube is to be so placed as to leave an air space between it and the bottom of the bottle4 ,the thermometer is suspended in such a manner as to have the bulb as nearly as possible in the center of the melted fat4 ,the thermometer should be protected from air currents and should be kept perfectly still4 ,in case the congealing point is lower than room temperature the jacket may be immersed in a cooling mixture1 the temperature of which is only slightly below the freezing point of the fatty mass4 ,when crystals of fat begin to form1 the descent of the mercury in the stem of the thermometer will become very slow and finally reach a minimum1 which should be noted4 ,as the crystallization extends inwards and approaches the bulb of the thermometer a point will be reached when the mercury begins to rise4 ,at this time the partially crystallized mass should be vigorously stirred with the thermometer and again left at rest in as nearly1 the original position as possible4 ,by this operation the mercury will be made to rise and its maximum position should be noted as the true crystallizing point of the whole mass4 ,in comparing different samples1 it is important that the elements of time in which the first crystallization takes place should be kept1 as nearly as possible1 the same4 ,a unit of one hour in cooling the mixture from a temperature just above its point of fusion until the incipient crystallization is noticed1 is a convenient one for glycerids and for fat acids4 #bid4 ,determination of ,refractive ,power4--,the property of refracting light is possessed by fats in different degrees and these differences are of great help in analytical work4 ,the examination may be made by the simple refractometer of ,abbe or ,bertrand1 or by the more elaborate apparatus of ,pulfrich4 ,the comparative refractive power of fats can also be observed by means of the oleorefractometer of ,amagat-,jean or the differential refractometer of ,zune4#bdg ,for details of the construction of these apparatus1 with a description of the optical principles on which they are based1 the papers above cited may be consulted4 ,in this laboratory the instruments which have been employed are three in number1 viz41 ,abbe's small refractometer1 ,pulfrich's refractometer using yellow light1 and the oleorefractometer of ,amagat-,jean4 ,a brief description of the methods of manipulating these instruments is all that can be attempted in this manual4 #bie4 ,refractive ,index4--,refractive index is an expression employed to characterize the measurement of the degree of deflection caused in a ray of light in passing from one transparent medium into another4 ,it is the quotient of the sine of the angle of the incident1 divided by the sine of the angle of the refracted ray4 ,in the case of oils which remain liquid at room temperatures1 the determinations can be made without the aid of any device to maintain liquidity4 ,in the case of fat which becomes solid at ordinary room temperatures1 the determination must either be made in a room artificially warmed or the apparatus must have some device1 as in the later instruments of ,abbe and ,pulfrich1 and in the apparatus of ,amagat-,jean1 whereby the sample under examination can be maintained in a transparent condition4 ,in each case the accuracy of the apparatus should be tested by pure water1 the refractive index of which at #ah is #a4ccc4 ,the refractive index is either read directly on the scale as in ,abbe's instrument1 or calculated from the angles measured as in ,pulfrich's apparatus4 ,illustration3 ,,fig4 #hf4--;,,abbe',s ,,refractometer4 #bif4 ,abbe's ,refractometer4--,for practical use the small instrument invented by ,abbe will be found sufficient4 ,the one which has been in use for many years in this laboratory is shown in ,fig4 #hf4 ,the illustration represents the apparatus in the position preliminary to reading the index4 ,in preparing the sample of oil for observation the instrument is turned on its axis until the prisms between which the oil is placed assume a horizontal position1 as is seen in ,fig4 #hg4 ,the movable prism is unfastened and laid aside1 the fixed prism covered with a rectangular shaped piece of tissue paper on which one or two drops of the oil are placed4 ,the movable prism is replaced in such a manner as to secure a complete separation of the two prisms by the film of oiled tissue paper4 ,a little practice will enable the analyst to secure this result4 ,after the paper disk holding the fat is secured by replacing the upper prism1 the apparatus is placed in its normal position and the index moved until the light directed through the apparatus by the mirror shows the field of vision divided into dark and light portions4 ,the dispersion apparatus is now turned until the rainbow colors on the part between the dark and light fields have disappeared4 ,before doing this1 however1 the telescope1 the eyepiece of the apparatus1 is so adjusted as to bring the cross lines of the field of vision distinctly into focus4 ,the index of the apparatus is now moved back and forth until the line of the two fields of vision falls exactly at the intersection of the cross lines4 ,the refractive index of the fat under examination is then read directly upon the scale by means of a small magnifying glass4 ,to check the accuracy of the first reading1 the dispersion apparatus should be turned through an angle of #ahj until the colors have again disappeared1 and1 after adjustment1 the scale of the instrument again read4 ,these two readings should nearly coincide1 and their mean is the true reading of the fat under examination4 ,illustration3 ,,fig4 #hg4--;,,charging ,,position ,,of ,,refractometer4 ,for butter fats the apparatus should be kept in a warm place1 the temperature of which does not fall below #cj4 ,for reducing the results obtained to a standard temperature1 say #be1 the factor #j4jjjagf may be used4 ,as the temperature rises the refractive index falls4 ,example4--,refractive index of a butter fat determined at #cb4d #a4dedj1 reduced to #be as follows3 #cb4d -#be #g4d2 #j4jjjagf #g4d #j4jjac2 then #a4dedj #j4jjac #a4deec4 ,the instrument used should be set with distilled water at #ah1 the theoretical refractive index of water at that temperature being #a4ccc4 ,in the determination above given1 the refractive index of pure water measured #a4ccjj2 hence the above numbers should be corrected for theory by the addition of #j4jjcj1 making the corrected index of the butter fat mentioned at the temperature given1 #a4dehc4 #big4 ,pulfrich's ,refractometer4--,for exact scientific measurements1 ,pulfrich's apparatus has given here entire satisfaction4 ,in this instrument a larger quantity of the oil is required than for the abbe1 and this quantity is held in a cylindrical glass vessel luted to the top of the prism4 ,the method of accomplishing this and also an illustration of the refraction of the rays of light are shown in ,fig4 #hh4 ,illustration3 ,,fig4 #hh4--,,prism ,,of ,,pulfrich',s ,,refractometer4 ,the angle i is measured by a divided circle read with the aid of a small telescope4 ,the index of the prism of highly refractive glass ,n is known4 ,the oil is seen at n4 ,the light used is the yellow sodium ray 7,d74 ,from the observed angle the refractive index of n is calculated from the formula n ,n - sini4 ,for convenience the values of n for all usual values of i are computed once for all and arranged for use in tabular form4 ,the latest model of ,pulfrich's apparatus1 arranged both for liquid and solid bodies1 and also for spectrometric observation is shown in ,fig4 #hi4 ,when the sodium light is used it is placed behind the apparatus and the light is collected and reflected on the refractive prism by the lens ,n4 ,through ,h and ,g is secured the micrometric reading of the angle on the scale ,d by means of the telescopic arrangement ,f ,e4 ,for regulating the temperature of the oil and adjacent parts1 a stream of water at any desired temperature is made to circulate through ,l and ,s in the direction indicated by the arrows4 ,the manner in which this is accomplished is shown in the cross section of that part of the apparatus as indicated in ,fig4 #ij4 ,illustration3 ,,fig4 #hi4--,,pulfrich',s ,,new ,,refractometer4 ,illustration3 ,,fig4 #ij4--;,,heating ,,apparatus ,,for ,,pulfrich',s ,,refractometer4 ,illustration3 ,,fig4 #ia4--,,spectrometer ,,attachment4 ,for further details of the construction and operation of the apparatus the original description may be consulted4#bdh ,in case a spectrometric observation is desired the ,h ray1 for instance1 is produced by the geissler tube ,q1 ,fig4 #ia4 ,the light is concentrated and thrown upon the refractive prism by the lens ,p1 the lens ,n1 ,fig4 #hi1 being removed for this purpose4 ,tables1 for correcting the dispersion and for calculating the indices for each angle and fraction thereof1 and for corrections peculiar to the apparatus1 accompany each instrument4 #bih4 ,refractive ,indices of some ,common ,oils4--,the following numbers show the refractive indices obtained by ,long for some of the more common oils4 ,the light used was the yellow ray of the sodium flame4#bdi ,refractive ,calculated ,name4 ,temperature4 index4 for #be4 ,olive oil 7,france7 #bf4f #a4dfgc #a4dfgg 0 0 7,california7 #be4d #a4dfgg #a4dfgh ,cottonseed oil #bd4h #a4dgbb #a4dgba 0 0 #bf4c #a4dgjc #a4dgji 0 0 #be4c #a4dgah #a4dgai ,sesam oil #bd4h #a4dgbh #a4dgbh 0 0 #bf4h #a4dgaj #a4dgaf ,castor 0 #be4d #a4dgga #a4dggc ,lard 0 #bg4c #a4dfeg #a4dfff ,peanut 0 #be4c #a4dfif #a4dfif ,in case of the use of ,abbe's apparatus1 in which diffused sunlight is the source of the illumination1 the numbers obtained cannot be compared directly with those just given unless the apparatus be first so adjusted as to read with distilled water at #ah1 #a4ccc4 ,in this case the reading of the scale gives the index as determined by the yellow ray4 ,the numbers obtained with ,abbe's instrument for some common oils are given below4#bej ,in the determinations the instrument was set with water at #ah1 reading #a4ccjj1 and they were corrected by adding #j4jjcj in order to compensate for the error of the apparatus4 ,material4 ,calculated for #be4 ,corrected index4 ,lard #a4dfbj #a4dfej ,cotton oil #a4dfgd #a4dgjd ,olive oil stearin #a4dehb #a4dfaj ,lard stearin #a4deid #a4dfbd #bii4 ,oleorefractometer4--,instead of measuring the angular value of the refractive power of an oil it may be compared with some standard on a purely arbitrary scale4 ,such an apparatus is illustrated by the oleorefractometer of ,amagat-,jean1 or by ,zeiss's butyrorefractometer4 ,in the first named instrument1 ,fig4 #ib1 the oil to be examined is compared directly with another typical oil and the shadow produced by the difference in refraction is located on a scale read by a telescope and graduated for two different temperatures4#bea ,the internal structure of the apparatus is shown in ,fig4 #ic4 ,illustration3 ,,fig4 #ib4--,,oleorefractometer4 ,illustration3 ,,fig4 #ic4--,,section ,,showing ,,construction ,,of ,,oleorefractometer4 ,in the center of the apparatus a metal cylinder1 ,a1 is found carrying two plate glass pieces1 ,c ,b1 so placed as to form an angle of #ajg4 ,this cylinder is placed in a larger one1 provided with two circular glass windows4 ,to these two openings are fixed to the right and left1 the telescopic attachments1 ,g1 ,v1 ,s1 ,e1 and the apparatus ,m1 ,h1 ,s1 ,e1 for rendering the rays of light parallel4 ,the field of vision is divided into two portions1 light and dark1 by a semicircular stop inserted in the collimator1 and contains the double scale shown in the figure placed at ,h4 ,the field of vision is illuminated by a gas or oil lamp placed at a convenient distance from the collimator4 ,the inner metallic cylinder ,a is surrounded with an outer one1 to which the optical parts are attached at ,d ,d by means of plane glass plates4 ,this cylinder is in turn contained in the large water cylinder ,p ,p1 carrying a thermometer in the opening shown at the top on the left4 ,the manipulation of the apparatus is very simple4 ,the outer cylinder is filled with water1 at a temperature below #bb1 the middle one with the typical oil furnished with the instrument1 the cover of the apparatus carrying the thermometer placed in position and the cup-shaped funnel inserted in the cylinder ,a1 which is at first also filled with the typical oil4 ,the whole system is next brought slowly to the temperature of #bb by means of the lamp shown in ,fig4 #ib4 ,the telescope is adjusted to bring the scale of the field of vision into focus and the line dividing the light and shadow of the field should fall exactly on #j;a4 ,if this be not the case the #j is adjusted by screws provided for that purpose until it is in proper position4 ,the typical oil is withdrawn from ,a by the cock ,r1 the cylinder washed with a little of the oil to be examined and then filled therewith4 ,on again observing the field of vision the line separating the shadow from the light will be found moved to the right or left1 if the oil have an index different from that of the typical oil4 ,the position of the dividing line is read on the scale4 ,for fats the temperature of the apparatus is brought exactly to #de and the scale #j;b is used4 ,in other respects the manipulation for the fats is exactly that described for oils4 ,in the use of #j;a1 in case the room be warmer than #bb1 all the liquids employed should be cooled below #bb before being placed in the apparatus4 ,it is then only necessary to wait until the room temperature warms the system to #bb4 ,in the case of fats it is advisable to heat all the liquids to about #ej and allow them to cool to #de instead of heating them to that temperature by means of the lamp4 ,one grave objection to this instrument is found in the absence of the proper scientific spirit controlling its manufacture and sale1 as evidenced by the attempt to preserve the secret of the composition of the typical oil and the negligence in testing the scale of the instruments which will be pointed out further along4 ,according to ,jean#beb the common oils1 when purified1 give the following readings at #bb3 ,peanut oil #c4e to #f4e ,colza 0 #ag4e 0 #ba4j ,cotton 0 #ah4j 0 #ah4j ,linseed 0 #dg4j 0 #ed4e ,lard 0 #e4e 0 #e4e ,olive 0 #a4e 0 #j4j ,sesam 0 #ag4e 0 #ai4j ,oleomargarin -#ae4j 0 -#ae4j ,butter fat -#cj4j 0 -#cj4j ,mutton oil #j4j 0 #j4j ,fish 0 #ch4j 0 #ch4j ,in this instrument1 therefore1 vegetable and fish oils1 as a rule1 show a right hand1 and animal fats a left hand deviation4 ,the oleorefractometer has been extensively used in this laboratory and the data obtained thereby have been found useful4 ,we have not found1 however1 the values fixed by ,jean to be constant4 ,the numbers for lard have varied from -#c4j to -#aj4j1 and other fats have shown almost as wide a variation from the values assigned by him4 ,jean states that the number for lard1 determined by the oleorefractometer1 is -#ab1 and he gives a definite number for each of the common oils and fats4 ,on trying the pure lards of known origin in this instrument1 ,i have never yet found one that showed a deviation of -#ab divisions of the scale2 but ,i have no doubt that there are many such lards in existence4 ,the pure normal lards derived from the fat of a single animal would naturally show greater variations in their chemical and physical properties1 than a typical lard derived from the mixed fats of a great many animals4 ,in leaf lard1 rendered in the laboratory1 the reading of the oleorefractometer was found to be -#aj1 while with the intestinal lard it was -#i4 ,on the other hand1 a lard rendered from the fat from the back of the animal showed a reading of only -#c1 and a typical cottonseed oil a reading of #ab4 ,according to the statement of ,jean1 a lard which gives even as low a refractive number as -#i1 by his instrument1 would be adjudged at least one-quarter cottonseed oil4 ,after a thorough trial of the instrument of ,jean1 ,i am convinced that it is of great diagnostic value1 but if used in the arbitrary manner indicated by the author it would lead to endless error and confusion4 ,in other words1 this instrument is of greater value in analyses than ,abbe's ordinary refractometer1 because it gives a wider expansion in the limits of the field of vision1 and therefore can be more accurately read1 but it is far from affording a certain means of discovering traces of adulteration with other fats4 #cjj4 ,variations in the ,instruments4--,in the use of the oleorefractometer1 attention should be called to the fact that1 through some negligence in manufacture1 the instruments do not give1 in all instances1 the same reading with the same substance4 ,allen obtained the following data with a sample of lard examined in three instruments1 viz41 #d4e1 #f1 and #aa4 ,such wide differences in the scales of the instruments cannot fail to disparage the value of comparative determinations4 ,the variations in samples of known origin1 when read on the same instrument1 however1 will show the range of error to which the determinations made with the oleorefractometer are subject4 ,pearmain has tabulated a large number of observations of this kind1 covering #bdj samples of oils4#bec ,following are the data relating to the most important oils4 ,,at #bb4 ,highest ,lowest ,mean reading4 reading4 reading4 ,name of oil4 ,degrees4 ,degrees4 ,degrees4 ,almond #aj4e #h4j #i4e ,peanut #g4j #e4j #f4j ,castor #db4j #ci4j #dj4j ,codliver #df4j #dj4j #dd4j ,cottonseed 7crude7 #ag4j #af4j #af4e 0 7refined7 #bc4j #ag4j #ba4e ,lard oil -#a4j #j4j #j4j ,linseed 7crude7 #eb4j #dh4j #ej4j 0 7refined7 #ed4j #ej4j #eb4e ,olive #c4e #a4j #b4j ,rape #bj4j #af4j #ag4e ,sesam #ag4j #ac4j #ae4e ,sunflower #ce4j #ce4j #ce4j ,tallow oil -#e4j -#a4j -#c4j ,oleic acid -#cc4j -#bi4j -#cb4j ,,at #de4 ,butter -#cd4j -#be4j -#cj4j ,oleomargarin -#ah4j -#ac4j -#ae4j ,lard -#ad4j -#h4j -#aj4e ,tallow -#ah4j -#ae4j -#af4j ,paraffin #eh4e #ed4j #ef4j ,illustration3 ,,fig4 #id4--;,,butyrorefractometer4 #cja4 ,butyrorefractometer4--,another instrument graduated on an arbitrary scale is the butyrorefractometer of ,zeiss4 ,this apparatus1 which resembles in some respects the instrument of ,abbe1 differs therefrom essentially in dispensing with the revolving prisms of ,amici1 whereby the chromatic fringing due to dispersion is corrected1 and on having the scale fixed for one substance1 in this instance1 pure butter fat4 ,the form of the instrument is shown in ,fig4 #id4 ,the achromatization for the butter fat is secured in the prisms between which a film of the fat is placed1 as in the ,abbe instrument4 ,when a fat1 differing from that for which the instrument is graduated is introduced1 the fringes of the dark and light portions of the field will not only be colored 7difference in dispersion71 but the line of separation will also be displaced 7difference in refractive power74 ,the apparatus is therefore used in the differential determination of these two properties4 ,it must not be forgotten1 however1 that butter fats differ so much in these properties among themselves as to make possible the condemnation of a pure as an adulterated sample4 #cjb4 ,method of ,charging the ,apparatus4--,the prism casing of the instrument is opened by turning the pin ,f to the right and pushing the half ,b of the prism casing aside4 ,the prism and its appendages must be cleaned with the greatest care1 the best means for this purpose being soft clean linen moistened with a little alcohol or ether4 ,melt the sample of butter in a spoon and pour it upon a small paper filter held between the fingers and apply the first two or three drops of clear butter fat so obtained to the surface of the prism contained in prism casing ,b4 ,for this purpose the apparatus should be raised with the left hand so as to place the prism surface in a horizontal position4 ,press ,b against ,a and replace ,f by turning it in the opposite direction into its original position2 thereby ,b is prevented from falling back and both prism surfaces are kept in close contact4 #cjc4 ,method of ,observation4--,while looking into the telescope1 give the mirror ,j such a position as to render the critical line which separates the bright left part of the field from the dark right part distinctly visible4 ,it may also be necessary to move or turn the instrument about a little4 ,first it will be necessary to ascertain whether the space between the prism surfaces be uniformly filled with butter1 for1 if not1 the critical line will not be distinct4 ,by allowing a current of water of constant temperature to flow through the apparatus1 some time previous to the taking of the reading1 the at first somewhat hazy critical line approaches in a short time1 generally after a minute1 a fixed position and quickly attains its greatest distinctness4 ,when this point has been reached note the appearance of the critical line 7i4 e41 whether colorless or colored and in the latter case of what color72 also note the position of the critical line on the centesimal scale1 which admits of the tenth divisions being conveniently estimated1 and at the same time read the thermometer4 ,by making an extended series of successive readings and by employing an assistant for melting and preparing the small samples of butter1 from twenty-five to thirty refractometric butter tests may1 after a little practice1 be made in an hour4 ,the readings of the refractive indices of a large number of butter samples made at #be are1 by means of a table which will be found below1 directly reduced to scale divisions and yield the following equivalents3#bed ,natural butter 7#a4deij-a4dfbj7 3 #di4e-ed4j scale divisions4 ,margarin 7#a4dfej-a4dgjj7 3 #eh4f-ff4d 0 0 ,mixtures 7#a4dfbj-a4dfij7 3 #ed4j-fd4h 0 0 ,whenever1 in the refractometric examination of butter at a temperature of #be1 higher values than #ed4j are found for the critical lines these samples will1 according to ,wollny1 by chemical analysis1 always be found to be adulterated2 but in all samples in which the value for the position of the critical line does not fall below #eb4e1 chemical analysis maybe dispensed with and the samples may be pronounced to be pure butter4 ,in calculating the position of the critical line for other temperatures than #be allow for #a variation of temperature a mean value of #j4ee scale division4 ,the following table1 which has been compiled in this manner1 shows the values corresponding to various temperatures1 each value being the upper limit of scale divisions admissible in pure butter3 ,temp4 ,sc4 div4 ,temp4 ,sc4 div4 ,temp4 ,sc4 div4 ,temp4 ,sc4 div4 #de #da4e #dj #dd4b #ce #dg4j #cj #di4h #dd #db4j #ci #dd4h #cd #dg4e #bi #ej4c #dc #db4f #ch #de4c #cc #dh4a #bh #ej4h #db #dc4a #cg #de4i #cb #dh4f #bg #ea4d #da #dc4g #cf #df4d #ca #di4b #bf #ea4i #dj #dd4b #ce #dg4j #cj #di4h #be #eb4e ,if1 therefore1 at any temperature between #de and #be values be found for the critical line1 which are less than the values corresponding to the same temperature according to the table1 the sample of butter may safely be pronounced to be natural1 i4 e41 unadulterated butter4 ,if the reading show higher numbers for the critical line the sample should be reserved for chemical analysis4 ,a special thermometer for use in the examination of butter will be described in the section devoted to dairy products4 #cjd4 ,range of ,application of the ,butyrorefractometer4--,the extended range of the ocular scale of the refractometer1 n #a4db to #a4di1 which embraces the refractive indices of the majority of oils and fats1 renders the instrument applicable for testing oils and fats and also for examining glycerol4 ,by reference to the subjoined table the scale divisions may be transformed into terms of refractive indices4 ,it gives the refractive indices for yellow light for every ten divisions of the scale4 ,the differential column gives the change of the refractive indices in terms of the fourth decimal per scale division4 ,owing to the accuracy with which the readings can be taken 7#j4a scale division7 the error of the value of n rarely exceeds one unit of the fourth decimal of n4 ,,table ,,of ,,refractive ,,indices4 ,scale div4 n,d4 4 ,scale div4 n,d4 4 #j #a4dbbj #h4j #ej #a4deic #f4f #aj #a4dcjj #g4g #fj #a4dfej #f4d #bj #a4dcgg #g4e #gj #a4dgbc #f4j #cj #a4ddeb #g4b #hj #a4dghc #e4g #dj #a4debd #f4i #ij #a4dhdj #e4e #ej #a4deic #ajj #a4dhie ,the process of observation is precisely the same as that already described4 ,in cases1 however1 where the critical line presents very broad fringes 7turpentine1 linseed oil1 etc47 it is advisable to repeat the reading with the aid of a sodium flame4 #cje4 ,viscosity4--,an important property of an oil1 especially when its lubricating qualities are considered1 is the measure of the friction which the particles exert on other bodies and among themselves1 in other words1 its viscosity4 ,in the measure of this property no definite element can be considered1 but the analyst must be content with comparing the given sample with the properties of some other liquid regarded as a standard4 ,the usual method of procedure consists in determining the time required for equal volumes of the two liquids to pass through an orifice of given dimensions1 under identical conditions of temperature and pressure4 ,in many instances the viscosity of oils is determined by comparing them with water or rape oil1 while1 in other cases1 a solution of sugar is employed as the standard of measurement4 ,in case rape oil be taken as a standard and its viscosity represented by #ajj the number representing the viscosity of any other oil may be found by multiplying the number of seconds required for the outflow of fifty cubic centimeters by #ajj and dividing by #ece4 ,if the specific gravity vary from that of rape oil1 viz41 #j4iae1 at #ae1 a correction must be made by multiplying the result obtained above by the specific gravity of the sample and dividing the product by #j4iae4 ,if n be the observed time of outflow in seconds and s the specific gravity the viscosity is expressed as follows3#bee n #ajj s n #ajj s ,v ---------------- ----------------4 #ece #j4aie #dhi4ebe ,illustration3 ,,fig4 #ie4--;,,doolittle',s ,,viscosimeter4 ,it is important that the height of the oil in the cylinders from which it is delivered be kept constant1 and this is secured by supplying additional quantities1 on the principle of the mariotte bottle4 #cjf4 ,the ,torsion ,viscosimeter4--,in this laboratory the torsion viscosimeter1 based on the principle described by ,babcock is used4 ,the instrument employed is the one described by ,doolittle4#bef ,the construction of the apparatus is illustrated in ,fig4 #ie4 ,a steel wire is suspended from a firm support and fastened to a stem which passes through a graduated horizontal disk1 thus permitting the accurate measurement of the torsion of the wire4 ,the disk is adjusted so that the index point reads exactly #j1 thus showing that there is no torsion in the wire4 ,a brass cylinder seven centimeters long by five in diameter1 having a slender stem by which to suspend it1 is immersed in the oil and fastened by a thumbscrew to the lower part of the stem of the disk4 ,the oil cup is surrounded by a bath of water or high fire-test oil1 according to the temperature at which it is desired to determine the viscosity4 ,this temperature obtained1 while the disk is resting on its supports1 the wire is twisted #cfj by rotating the milled head at the top4 ,the disk being released1 the cylinder rotates in the oil by virtue of the torsion of the wire4 ,the action now observed is identical with that of the simple pendulum4 ,if there were no resistance to be overcome1 the disk would return to #j1 and the momentum thus acquired would carry it #cfj in the opposite direction4 ,but the resistance of the oil to the rotation of the cylinder causes the revolution to fall short of #cfj1 and the greater the viscosity of the oil the greater will be the resistance1 and also the retardation4 ,this retardation is found to be a very delicate measure of the viscosity of the oil4 ,this retardation may be read in a number of ways1 but the simplest is to read directly the number of degrees of retardation between the first and second complete arcs covered by the rotating pendulum4 ,for example1 suppose the wire be twisted #cfj and the disk released so that rotation begins4 ,in order to obtain an absolute reading to start from1 which shall be independent of any slight error in adjustment1 ignore the starting point and make the first reading of the index at the end of the first swing4 ,the disk is allowed to complete a vibration and the needle is read again at its nearest approach to the first point read4 ,the difference in the two readings will measure the retardation due to the viscosity of the liquid4 ,in order to eliminate errors duplicate determinations are made1 the milled head being rotated in an opposite direction in the second one4 ,the mean of the two readings will represent the true retardation4 ,each instrument is standardized in a solution of pure cane sugar1 as proposed by ,babcock1 and the viscosity1 in each case1 is a number representing the number of grams of sugar in #ajj cubic centimeters1 which1 at #bb1 would produce the retardation noted4 ,each instrument is accompanied by a table which contains the necessary corrections for it and the number expressing the viscosity1 corresponding to the different degrees of retardation1 as read on the index4 ,the following numbers1 representing the viscosity of some oils as determined by the method of ,doolittle1 were obtained by ,krug4#beg ,peanut oil #dh4ej ,olive 0 #ec4jj ,cottonseed 0 #df4be ,linseed 0 #cc4ej #cjg4 ,microscopic ,appearance4--,when fats are allowed to slowly crystallize from an ethereal solution they may afford crystalline forms1 which1 when examined with a magnifying glass1 yield valuable indications of the nature and origin of the substance under examination4#beh ,the method of securing fat crystals for microscopic examination1 which has been used in this laboratory1 is as follows3 ,from two to five grams of the fat are placed in a test tube and dissolved in from ten to twenty cubic centimeters of ether4 ,the tube is loosely stoppered with cotton and allowed to stand1 for fifteen hours or longer1 in a moderately warm room where no sudden changes of temperature are likely to take place4 ,it is advisable to prepare several solutions of the same substance with varying properties of solvent1 for it is not possible to secure in a given instance those conditions which produce the most characteristic crystals4 ,the rate and time of the crystallization should be such that the microscopic examination can take place when only a small portion of the fat has separated in a crystalline condition4 ,a drop of the mass containing the crystals is removed by means of a pipette1 placed on a slide1 a drop of cotton or olive oil added1 a cover glass gently pressed down on the mixture and the preparation subjected to microscopic examination4 ,several slides should be prepared from the same or different crystallizations4 ,sometimes the results of an examination made in this way are very definite1 but the analyst must be warned not to expect definite data in all cases4 ,often the microscopic investigations result in the production of negative or misleading observations1 and1 at best1 this method of procedure must be regarded only as helpful and confirmatory4 ,a modification of the method of preparation described above has been suggested by ,gladding4#bei ,about five grams of the melted fat are placed in a small erlenmeyer1 dissolved in a mixture of ten cubic centimeters of absolute alcohol mixed with half that quantity of ether4 ,the flask is stoppered with a plug of cotton and allowed to stand in a cool place for about half an hour4 ,by this treatment the more easily crystallizable portions of the fat separate in a crystalline form1 while the triolein and its nearly related glycerids remain in solution4 ,the crystalline product is separated by filtration through paper wet with alcohol and washed once with the solvent mentioned above4 ,after drying in the air for some time the crystals are removed from the paper and dissolved in twenty-five cubic centimeters of ether1 the cotton plug inserted1 and the erlenmeyer placed1 in a standing position1 in a large beaker containing water4 ,the water jacket prevents any sudden changes of temperature and affords an opportunity for the uniform evaporation of the ether which should continue for fifteen hours or longer in a cool place4 ,other solvents1 viz41 alcohol1 chloroform1 carbon disulfid1 carbon tetrachlorid1 petroleum and petroleum ether have been extensively used in the preparation of fat crystals for microscopic examination1 but in our experience none of these is equal to ether when used as already described4 #cjh4 ,microscopic ,appearance of ,crystals of ,fats4--,for an extended study and illustration of the characteristics of fat crystals the bulletin of the ,division of ,chemistry1 already cited1 may be consulted4 ,in the case of lard1 there is a tendency1 more or less pronounced1 to form prismatic crystals with rhombic ends4 ,beef fat on the other hand shows a tendency to form fan-shaped crystals in which the radii are often curved4 ,typical crystals of swine and beef fat are shown in the accompanying figures1 #if and #ig4bfj ,in mixtures of swine and beef fats the typical crystals are not always developed1 but in most cases the fan-shaped crystals of the beef fat will appear more or less modified when that fat forms twenty per cent or more of the mixture4 ,when only five or ten per cent of the beef fat on the one hand or a like amount of swine fat on the other are present the expectation of developing any characteristic crystals of the minimum constituent is not likely to be realized4 ,the typical crystals of lard are thought by some experts to be palmitin and those of beef fat stearin1 but no direct evidence has been adduced in support of these a priori theories4 ,in the experience of this laboratory1 as described by ,crampton1#bfa the differences between the typical crystallization of beef and swine fats are plainly shown4 ,in mixed fats1 on the contrary1 confusing observations are often made4 ,in a mixture of ten per cent of beef and ninety per cent of swine fats a uniform kind of crystallization is observed1 not distinctly typical1 but the characteristics of the lard crystals predominate4 ,in many cases a positive identification of the crystals is only made possible by repeated crystallizations4 ,in the examination of so-called refined lards1 which are mixtures of lard and beef fat1 the form of aggregation of the crystals is found to resemble the fan-shaped typical forms of beef fat4 ,when the single crystals1 however1 are examined with a higher magnifying power1 they are not found to be pointed but blunt1 and some present the appearance of plates with oblique terminations1 but not so characteristic as those obtained from pure lard4 ,in other cases in compound lards no beef fat crystals are observed and these lards may have been made partly of cotton oil stearin4 ,when a lard crystal presents its edge to observation it may readily escape identification1 or may even be mistaken for a crystal of beef fat4 ,in order to insure a side view the cover glass should be pressed down with a slight rotatory movement1 whereby some of the lard crystals at least may be made to present a side view4 #cji4 ,observation of ,fat ,crystals with ,polarized ,light4--,the appearance of fat crystals1 when observed by means of polarized light alone or with the adjunct of a selenite plate1 is often of value in distinguishing the nature and origin of the sample4#bfb ,every fat and oil which is amorphous will present the same set of phenomena when observed with polarized light through a selenite plate1 but when a fat has been melted and allowed to cool slowly the field of vision will appear mottled and particolored when thus examined4 ,this method has been largely used in the technical examination of butter for adulterants1 and the microscope is extensively employed by the chemists of the ,bureau of ,internal ,revenue for this purpose4 ,in the examination of the crystals of butter fat by polarized light a cross is usually observed when the nicols are turned at the proper angle1 but the cross1 while almost uniformly seen with butter1 is not distinctive1 since other fats often show it4 ,these forms of crystals are best obtained by heating the butter fat to the boiling-point of water for about a minute and then allowing it to slowly solidify1 and stand for twenty-four hours4 ,pure butter1 properly made1 is never subjected to fusion1 and hence1 when examined through a selenite plate1 presents a uniform field of vision similarly illuminated and tinted throughout4 ,in oleomargarin1 the fats are sometimes1 during their preparation1 in a fused condition4 ,the field of vision is therefore filled to a greater or less extent with crystals more or less perfect in form4 ,some of these crystals1 being doubly refracting1 will impart to a selenite field a mottled appearance4 ,such a phenomenon is therefore indicative of a fraudulent butter or of one which has been at some time subjected to a temperature at or above its fusing point4 #caj4 ,spectroscopic ,examination of ,oils4--,the presence of chlorophyll or of its alteration products is a characteristic of crude oils of vegetable origin4 ,in refined oils1 even when of a vegetable origin1 all traces of the chlorophyll products may disappear4 ,the absorption bands given by oils are not all alike and in doubtful cases a suspected sample should be compared with one of known origin4 ,in conducting the examination1 the oil in a glass vessel with parallel sides1 is placed in front of the slit of the spectroscope and any absorption band is located by means of the common divided scale and by the color of the spectrum on which it falls4 ,olive and linseed oils give three sharply defined absorption bands1 a very dark one in the red1 a faint one on the orange and a well marked one in the green4 ,sesame1 arachis1 poppyseed and cottonseed oils also show absorption bands4 ,castor and almond oils do not affect the spectrum4 ,illustration3 ,fig4 #if4 ,,lard ,,crystals #fe4 ,illustration3 ,fig4 #ig4 ,,refined ,,lard 7,,beef ,,fat7 ,,crystals #fe4 ,a4 ,hoen ,co41 ,lithocaustic4 ,rape and flaxseed oils absorb a part of the spectrum but do not affect the rest of it4 ,the spectroscope is of little practical utility in oil analysis4#bfc #caa4 ,critical ,temperature of ,solution4--,the study of the critical temperature of solution of oils has been made by ,crismer1 who finds it of value in analytical work4#bfd ,if a fatty substance be heated under pressure1 with a solvent1 e4 g41 alcohol1 it will be noticed that as the temperature rises the meniscus of separation of the two liquids tends to become a horizontal plane4 ,if at this point the contents of the tube be thoroughly mixed by shaking and then be left at rest1 a point will soon be reached at which the two liquids again separate1 and this point is distinctly a function of temperature4 ,following is a description of a convenient method of determining the critical temperature of the solution of fats and oils for experimental purposes4 ,tubes are prepared for holding the reagents in such a way that1 after the introduction of the fat and alcohol1 they can be easily sealed4 ,the capacity of these tubes should be about five cubic centimeters4 ,they should be charged with about one cubic centimeter of the dry filtered fat and about twice that quantity of ninety-five per cent alcohol4 ,care should be exercised to avoid touching the upper sides of the tube with the reagents4 ,when charged the tubes are sealed in the flame of a lamp and attached to the bulb of a delicate thermometer in such a manner as to have the surface of its liquid contents even with the top of the bulb4 ,the tube is conveniently fastened to the thermometer by a platinum wire4 ,for duplicate determinations two tubes may be fastened to the same thermometric bulb4 ,the apparatus thus prepared is placed in a large vessel filled with strong sulfuric acid4 ,the operator should be careful to protect himself from the danger which might arise from an explosion of the sealed tubes during heating4 ,it is advisable in all cases to observe the reaction through a large pane of clear glass4 ,the bath of sulfuric acid is heated by any convenient means and an even temperature throughout the mass is secured by stirring with the thermometer and its attachments4 ,when the meniscus which separates the two liquids becomes a horizontal plane the thermometer is removed and the liquid in the tubes well mixed until it appear homogeneous4 ,the thermometer is replaced in the bath1 which is allowed to cool slowly1 and the phenomena which take place in the sealed tubes are carefully noted4 ,the critical temperature of solution is that at which the two liquids begin to separate4 ,this moment is easily noted4 ,it is1 moreover1 preceded by a similar phenomenon taking place in the capillary part of the tube which retains a drop of the mixture on shaking4 ,in this droplet an opalescence is first noted4 ,in the mass of the liquid this opalescence1 a few seconds afterwards1 is observed to permeate the whole1 followed by the formation of zones and finally of the reappearance of the meniscus of separation between the two liquids4 ,the temperature at this moment of opalescence preceding the separation of the liquid is the critical temperature of solution4 ,with alcohol of #j4haie specific gravity1 at #ae4e 7ninety-five per cent71 the observed critical temperatures for some of the more common fats and oils are as given below3 ,butter fat #ajj4j ,oleomargarin #abe4j ,peanut oil #abc4j ,cotton 0 #aaf4j ,olive 0 #abc4j ,sesam 0 #aba4j ,colza 0 #acb4e ,mutton tallow #aaf4j ,beef marrow #abe4j ,nut oil #ajj4e ,when the alcohol is not pure or if it be of a different density from that named1 the numbers expressing the critical temperature of solution will vary from those given above4 #cab4 ,polarization4--,the pure glycerids are generally neutral to polarized light4 ,in oils the degree of polarization obtained is often variable1 sometimes to the right and sometimes to the left4 ,olive oil1 as a rule1 shows a slight right hand polarization4 ,peanut1 sesam1 and cottonseed oils vary in polarizing power1 but in no case is it very marked4 ,castor oil polarizes slightly to the right4 ,in determining the polarizing power of an oil it should be obtained in a perfectly limpid state by filtration and observed through a tube of convenient length1 as a rule1 #bjj millimeters4 ,the deviation obtained may be expressed in divisions of the sugar scale of the instrument or in degrees of angular rotation4 #cac4 ,turbidity ,temperature4--,the turbidity temperature of a fat1 when dissolved in glacial acetic acid1 as suggested by ,valenta1 may prove of some diagnostic value4#bfe ,the fats are dissolved1 with the aid of heat1 in glacial acetic acid and1 on slowly cooling1 the temperature at which they become turbid is observed4 ,the following data observed by ,jones are given for comparison4#bff ,the numbers represent the turbidity temperature of the fat when treated with the glacial acetic acid1 and allowed to cool slowly4 ,butter fat1 from #dj to #gj1 mostly from #eb to #fe2 oleomargarin1 #ie to #ajf2 rape oil1 #aja2 sesam oil1 #gg2 linseed oil1 #ec to #eg2 lard oil1 #if2 olive oil1 #hi2 peanut oil1 #fa to #hh4 ,it is important in this test that the acetic acid be absolutely glacial4 ,about three cubic centimeters of the glacial acetic acid1 and three of the fat1 should be used4 ,,chemical ,,properties4 #cad4 ,solubility in ,alcohol4--,as has already been noted1 the glycerids are freely soluble in ether1 chloroform1 carbon bisulfid1 acetone1 carbon tetrachlorid1 and some other less commonly used solvents4 ,their solubility in absolute alcohol is variable and the determination of its degree may often be useful in analytical work4 ,the method used by ,milliau for determining the degree of solubility is as follows3#bfg ,the fatty matter is deprived of its free acids by shaking for half an hour with twice its volume of ninety-five per cent alcohol4 ,after standing until the liquids are separated1 the oil or fat is drawn off and washed three times with distilled water4 ,the sample is deprived of water by filtering through a hot jacket filter and a given weight of the dry sample is well shaken with twice its weight of absolute alcohol4 ,a weighed portion of the alcoholic solution obtained is evaporated to remove the alcohol and the weight of the residual fat determined4 ,from the data obtained the percentage of solubility is calculated4 ,olive oils1 when treated as described above1 show a solubility of about forty-three parts per thousand of absolute alcohol1 cotton oil sixty-two parts1 sesam forty-one parts1 peanut sixty-six parts1 colza twenty parts1 and flaxseed seventy parts per thousand4 #cae4 ,coloration ,produced by ,oxidants4--,when oils and fats are mixed with oxidizing reagents1 such as sulfuric and nitric acids1 the glycerids are partly decomposed with the production of colors which have some analytical significance4 ,the most simple method of applying these tests is by the use of a thick porcelain plate provided with small cup-shaped depressions for holding the few drops of material required4 ,two or three drops of the oil under examination are placed in each of the cups1 a like quantity of the oxidizing reagent added1 and the mixture stirred with a small glass rod4 ,the colors produced are carefully noted and the mixture is allowed to remain at room temperature for at least twelve hours in order that the final tint may be observed4 ,the sulfuric acid used for this reaction should have a specific gravity of one and seven-tenths and the nitric acid should have the usual commercial strength of the strongest acid4 ,pure lard1 when treated with sulfuric acid1 as above described1 shows but little change of color while the vegetable oils mostly turn brown or black4 ,in addition to the reagents mentioned many others1 including sulfuric and nitric acids1 sulfuric acid and potassium bichromate1 chlorin1 ammonia1 hydrogen peroxid1 sodium hydroxid and aqua regia are used4 ,only a few of these tests seem to have sufficient analytical importance to merit any detailed description4#bfh #caf4 ,coloration in ,large ,masses4--,instead of applying the color test in the small way just described1 larger quantities of the fat may be used1 either in the natural state or after solution in petroleum or other solvent4 ,for this purpose about ten cubic centimeters of the oil are shaken with a few drops of sulfuric acid or sulfuric and nitric acids4 ,lard1 when thus treated 7five drops of sulfuric acid to ten cubic centimeters of lard7 shows practically no coloration4 ,when treated with an equal volume of sulfuric acid and shaken1 the lard on separating has a brown-red tint4#bfi ,olive oil1 with a few drops of sulfuric acid1 gives a green color1 while cottonseed1 peanut and other vegetable oils1 when thus treated with sulfuric and nitric acids1 show brown to black coloration4 ,the delicacy of the reaction may be increased by first dissolving the fat or oil in petroleum ether4 ,in the use of the coloration test with solvents1 a convenient method is to dissolve about one cubic centimeter of the fat in a test tube in petroleum ether1 add one drop of strong sulfuric acid and shake4 ,in the case of lard1 the color does not change or becomes yellow or red4 ,cottonseed oil1 similarly treated1 shows a brown or black color4#bgj #cag4 ,special ,nitric ,acid ,test4--,a special nitric acid test for cottonseed oil is made with nitric acid of exactly #a4cge specific gravity at #ae4 ,this test is especially valuable in detecting cottonseed in olive oil4 ,the operation is conveniently conducted by shaking together equal volumes of the oil and acid in a test tube until an intimate mixture or emulsion is secured4 ,when any considerable quantity of cottonseed oil is present an immediate brown coloration is produced1 from the intensity of which the relative proportion of cottonseed oil in the case of a mixture may be roughly approximated4 ,when only a little cottonseed oil is present in the mixture1 the test tube containing the reagents should be set aside for several hours before the final observation is made4 #cah4 ,coloration with ,phosphomolybdic ,acid4--,among the color tests1 one which we have found of use is the coloration produced in certain oils1 mostly of a vegetable origin1 by phosphomolybdic acid4#bga ,the method of applying the test is extremely simple4 ,a few cubic centimeters of the oil or melted lard are dissolved in an equal volume of chloroform1 and a third volume of ten per cent phosphomolybdic acid added4 ,the mouth of the test tube is closed with the thumb1 and the whole is violently shaken4 ,on being left in repose1 the phosphomolybdic acid gathers at the top1 and the coloration produced therein is easily observed4 ,cottonseed oil and peanut oil both give a beautiful green when treated in this way1 which is turned to a blue on the addition of ammonia4 ,linseed oil gives a green color1 but forms a kind of emulsion which obscures the color to some extent4 ,the pure lards rendered in the laboratory give no coloration whatever to the reagent1 but it retains its beautiful amber color in every case4 ,mixtures containing as little as ten per cent cottonseed oil and ninety per cent lard1 show a distinct greenish tint1 while twenty per cent cottonseed oil gives a distinct green4 ,this reaction1 therefore1 may be considered of great value1 and on account of its easy application it should come into wide use4 ,but it is probable that different samples of cottonseed oil1 refined to different degrees or in different ways1 vary in their deportment with phosphomolybdic acid as they do with silver nitrate4 ,in other words1 there may be some samples of cottonseed oil which will not give the green color when treated as above1 or so faintly as to have no diagnostic value in mixtures4 ,this reaction shows itself with nearly all vegetable oils but those which have been chemically treated either for the purpose of bleaching1 or for the removal of the acidity1 do not respond to the test at all1 or else in a feeble manner1 and that only after standing some time4 ,lard1 goose fat1 tallow1 deer fat1 butter fat1 etc41 show no change in color on being treated with this reagent1 either with or without the addition of alkali4 ,the presence of a small quantity of vegetable oil betrays itself by the appearance of the above mentioned coloration1 the intensity of which forms an approximate measure of the amount of vegetable oil present in the sample4 ,in experiments with suspected lards1 which deviated in their iodin absorption numbers from those of genuine lard1 the results were concordant1 the color deepening as the iodin figure rose4 ,the mineral fats 7paraffin1 vaselin7 are without action on this reagent1 and the only animal fat which reduces it is codliver oil4 ,in like manner some samples of lard may be found which exhibit a deportment with this reagent similar to that shown with vegetable oils1 and tallow and lard oil have been shown to give more distinct reactions than some of the vegetable oils4#bgb ,the phosphomolybdic acid may be prepared by precipitating a solution of ammonium molybdate with sodium phosphate and dissolving the washed precipitate in a warm solution of sodium carbonate4 ,the solution is evaporated to dryness and the dry residue subjected to heat4 ,if a blue coloration be produced it may be discharged by adding a little nitric acid and reheating4 ,the residue is dissolved in water1 acidified with nitric and made of such a strength as to contain about ten per cent of the substance4 #cai4 ,coloration with ,picric ,acid4--,if to ten cubic centimeters of oil a cold saturated solution of picric acid in ether be added and the latter be allowed to evaporate slowly1 the acid remains dissolved in the oil1 to which it communicates a brown color4 ,pure lard1 after the evaporation of the ether1 appears of a citron-yellow color2 if cottonseed oil be present1 however1 the mixture assumes a brown-red color4#bgc #cbj4 ,coloration with ,silver ,nitrate4--,a modification of ,bechi's method of reducing silver nitrate1 given further on1 has been proposed by ,brull4#bgd ,the reagent employed consists of twenty-five parts of silver nitrate in #a1jjj parts of alcohol of ninety-five per cent strength4 ,twelve cubic centimeters of the oil to be examined and five of the reagent are placed in a test tube1 held in a vessel containing boiling water1 and the ebullition continued for about twenty minutes4 ,at the end of this time an olive oil1 even if it be an impure one1 will show a beautiful green tint4 ,with seed oils the results are quite different4 ,cotton oil submitted to this treatment becomes completely black4 ,peanut oil shows at first a brown-red coloration and finally a somewhat green tint1 losing its transparency4 ,sesam oil is distinguished by a red-brown tint very pronounced and remaining red4 ,colza oil takes on a yellowish green coloration1 becomes turbid and is easily distinguished in its reaction from olive oil4 ,in mixtures of olive oil with the other oils1 any notable proportion of the seed oils can be easily determined by the above reactions4 ,natural butter treated with this reagent retains its primitive color4 ,that containing margarin becomes a brick-red and as little as five per cent of margarin in butter can be detected by this test4 ,with ten per cent the tint is very pronounced4 #cba4 ,coloration with ,stannic ,bromid4--,this reagent is prepared by adding dry bromin1 drop by drop1 to powdered or granulated tin held in a flask immersed in ice water1 until a persistent red color indicates that the bromin is in excess4 ,in the application of this reagent three or four drops of it are added successively to a little less than that quantity of the oil1 the mixture well stirred and set aside for a few minutes4 ,the unsaponifiable matters of castor oil give a green color when thus treated1 sandal wood oil a blood-red color and cedar oil a purplish color4#bge #cbb4 ,coloration with ,auric ,chlorid4--,the use of auric chlorid for producing colorations in oils and fats was first proposed by ,hirschsohn4#bgf ,one gram of auric chlorid is dissolved in #bjj cubic centimeters of chloroform and about six drops of this reagent added to five cubic centimeters of the oil to be tested4 ,in the case of cottonseed oil a beautiful red color is produced4 ,i have found that even pure lards give a trace of color sometimes with this reagent1 and therefore the production of a slight red tint cannot in all cases be regarded as conclusive of the presence of cottonseed oil4#bgg ,in general1 it may be said that the color reactions with fats and oils have a certain qualitive and sorting value1 and in any doubtful case they should not be omitted4 ,their value can only be established by comparison under identical conditions with a large number of fats and oils of known purity4 ,the analyst must not depend too confidingly on the data found in books1 but must patiently work out these reactions for himself4 #cbc4 ,thermal ,reactions4--,the measurement of the heat produced by mixing glycerids with reagents which decompose them or excite other speedy chemical reactions1 gives valuable analytical data4 ,these measurements may be made in any convenient form of calorimeter4 ,the containing vessel for the reagents should be made of platinum or some other good conducting metal not affected by them4 ,the heat produced is measured in the usual way by the increment in temperature noted in the mass of water surrounding the containing vessel4 ,the determination of the heat produced in chemical reactions is a tedious and delicate operation requiring special forms of apparatus for different substances4 ,the time element in these operations is a matter of importance1 since it is necessary to work in rooms subject to slight changes of temperature and to leave the apparatus for some time at rest1 in order to bring it and its contents to a uniform temperature4 ,for these reasons the more elaborate methods of calorimetric examination are not well suited to ordinary analytical work1 and the reader is referred to standard works on thermal chemistry for the details of such operations4#bgh ,for our purpose here a description of two simple thermal processes1 easily and quickly conducted1 will be sufficient1 while a description of the method of determining the heat of combustion of foods will be given in another place4 #cbd4 ,heat of ,sulfuric ,saponification4--,maumen was the first to utilize the production of heat caused by mixing sulfuric acid with a fat as an analytical process4#bgi ,in conducting the process a sulfuric acid of constant strength should be employed inasmuch as the rise of temperature produced by a strong acid is much greater than when a weaker acid is employed4 ,the process is at best only comparative and it is evident that the total rise of temperature in any given case depends on the strength of the acid1 the character1 and purity of the fat or oil1 the nature of the apparatus and its degree of insulation1 the method of mixing and the initial temperature4 ,for this reason the data given by different analysts vary greatly4#bhj ,for some of the methods of conducting the operation the reader may consult the work of ,allen1 cited above1 or other authorities4#bha ,in this laboratory the process is conducted as follows3#bhb ,the initial temperature of the reagents should be a constant one4 ,for oils #bj is a convenient starting point and for fats about #ce1 at which temperature most of them are soft enough to be easily mixed with the reagent4 ,the acid employed should be the pure monohydrated form1 specific gravity at #bj1 #a4hde4 ,the apparatus used is shown in ,fig4 #ih4 ,illustration3 ,,fig4 #ih4--;,,apparatus ,,for ,,determining ,,rise ,,of ,,temperature ,,with ,,sulfuric ,,acid4 ,the test tube which holds the reagents is twenty-four centimeters in length and five in diameter4 ,it is provided with a stopper having three perforations1 one for a delicate thermometer1 one for a bulb funnel for delivering the sulfuric acid1 and one to guide a stirring rod bent into a spiral as shown4 ,the thermometer is read with a magnifying glass4 ,fifty cubic centimeters of the fat are placed in the test tube and ten of sulfuric acid in the funnel and the apparatus is exposed at the temperature desired until all parts of it1 together with the reagents1 have reached the same degree4 ,the test tube holding the oil should be placed in a vacuum-jacket tube1 such as will be described in paragraph #caf4 ,the oil is allowed to run in as rapidly as possible from the funnel and the stirring rod is moved up and down two or three times until the oil and acid are well mixed4 ,care must be exercised to stir no more than is necessary for good mixing4 ,the mercury is observed as it ascends in the tube of the thermometer and its maximum height is noted4 ,with the glass it is easy to read to tenths1 when the thermometer is graduated in fifths of a degree4 ,when oils are tested which produce a rise of temperature approaching #ajj1 in the above circumstances1 7cottonseed1 linseed and some others7 either smaller quantities should be used or the oil diluted with some inert substance or dissolved in some inert solvent of high boiling point4 ,for a study of the variations produced in the rise of temperature when varying proportions of oil and acid are used1 the work of ,munroe may be consulted4#bhc ,the thermlaeometer described by ,jean is a somewhat complicated piece of apparatus and does not possess any advantage over the simple form described above4#bhd ,instead of expressing the data obtained in thermal degrees showing the rise of temperature1 ,thompson and ,ballentyne refer them to the heat produced in mixing sulfuric acid and water4#bhe ,the observed thermal degree of the oil and acid divided by that of the water and acid is termed the specific temperature reaction4 ,for convenience in writing1 this quotient is multiplied by #ajj4 ,the respective quantities of acid and water are ten and fifty cubic centimeters4 ,this method of calculation has the advantage of eliminating to a certain degree the variations which arise in the use of sulfuric acid of differing specific gravities4 ,in the following table are given the comparative data obtained for some common oils4#bhf ,acid of #ie4d ,acid of #if4h ,acid of #ii per cent4 per cent4 per cent4 _/----------------- _/---------------- _/-------------- ,rise of ,specific ,rise of ,specific ,rise of ,specific temp4 temp4 temp4 temp4 temp4 temp4 with reaction4 with reaction with reaction4 ,kind of oil4 the oil4 the oil4 the oil4 #j #j #j #j #j #j ,olive oil #cf4e #ie #ci4d #he #dd4h #if ,rapeseed oil #di4j #abg #cg4j #hi #eh4j #abd ,castor oil #cd4j #hh ,linseed oil #ajd4e #bgj #abe4b #bfi #cbe4 ,method of ,richmond4--,the rise of temperature produced by mixing an oil and sulfuric acid is determined by ,richmond in a simple calorimeter1 which is constructed by fitting a small deep beaker inside a larger one with a packing of cotton4 ,the heat capacity of the system is determined by adding to ten grams of water1 in the inner beaker1 at room temperature1 twenty-five grams of water of a noted higher temperature and observing the temperature of the mixture4 ,the cooling of the system1 during the time required for one determination of heat of sulfuric saponification1 does not exceed one per cent of the whole number of calories produced4#bhg ,between the limits of ninety-two per cent and one hundred per cent the rise of temperature observed is directly proportional to the strength of the acid4 ,relative ,maumen ,figure4--,the total heat evolved per mean molecule is called by ,richmond the relative maumen figure4 ,it is calculated as follows3 ,let x percentage of sulfuric acid in the acid employed2 h heat capacity of calorimeter in grams of water2 ,r observed rise of temperature 7twenty-five grams of oil1 five cubic centimeters sulfuric acid72 ,k potash absorbed for saponification 7#ai4e per cent of potassium hydroxid1 standard of comparison72 ,m relative maumen figure3 #ba4e #bj h #ai4e ,then ,m ,r ----------- --------- -----4 x - #gh4e #bj ,k #cbf4 ,heat of ,bromination4--,the rise of temperature caused by mixing fats with sulfuric acid has long been used to discriminate between different fats and oils4 ,hehner and ,mitchell propose a similar reaction based upon the rise of temperature produced by mixing bromin with the sample4#bhh ,the action of bromin on unsaturated fatty bodies is instantaneous and is attended with a considerable evolution of heat4 ,since the action of bromin on many of the oils is very violent it is necessary to dilute the reagent with chloroform or glacial acetic acid4 ,owing to its high boiling point the acetic acid has some advantage over chloroform for this purpose4 ,the tests are conveniently made in a vacuum-jacket tube4 ,in such a tube there is no loss of heat by radiation4 ,the bromin is measured in a pipette having at its upper end a tube filled with caustic lime held between plugs of asbestos4 ,the bromin sample to be tested and the diluent employed are kept at the same temperature before beginning the trial4 ,they are quickly mixed and the rise of temperature noted4 ,the oil is first dissolved in the chloroform and the bromin then added4 ,a somewhat constant relation is noticed between the rise of temperature and the iodin number when one gram of oil1 ten cubic centimeters of chloroform and one cubic centimeter of bromin are used4 ,if the rise in temperature in degrees be multiplied by #e4e the product is approximately the iodin number of the sample4 ,thus a sample of lard gave a rise in temperature of #aj4f and an iodin number of #eg4ae4 ,the number obtained by multiplying #aj4f by #e4e is #eh4c4 ,in like manner the numbers obtained for some common oils are as follows3 ,material4 ,rise of temperature ,iodin ,no4 ,calculated with bromin4 ,iodin ,no4 ,butter fat #f4f #cg4a #cf4c ,olive oil #ae4j #hj4h #hb4e ,maize 0 #ba4e #abb4j #aah4b ,cotton 0 #ai4d #ajg4a #ajf4g ,castor 0 #ae4j #hc4h #hb4e ,linseed oil #cj4d #afj4g #afg4b ,codliver 0 #bh4j #add4j #adj4j #cbg4 ,modification of the ,heat of ,bromination ,method4--,the method described above by ,hehner and ,mitchell presents many grave difficulties in manipulation1 on account of the inconvenience of handling liquid bromin4 ,the process is made practicable by dissolving both the oil or fat and the bromin in chloroform1 or better in carbon tetrachlorid1 in which condition the bromin solution is easily handled by means of a special pipette4#bhi ,in order to make a number of analyses of the same sample ten grams of the fat may be dissolved in chloroform or carbon tetrachlorid and the volume completed with the same solvent to fifty cubic centimeters4 ,in like manner twenty cubic centimeters of the bromin are dissolved in one of the solvents named and the volume completed to #ajj cubic centimeters therewith4 ,for convenience of manipulation the solutions are thus made of such a strength that five cubic centimeters of each represent one gram of the fat and one cubic centimeter of the liquid bromin respectively4 ,illustration3 ,,fig4 #ii4 ,,apparatus ,,for ,,determining ,,heat ,,of ,,bromination4 ,the apparatus used for the work is shown in the accompanying figure4 ,the pipette for handling the bromin solution is so arranged as to be filled by the pressure of a rubber bulb1 thus avoiding the danger of sucking the bromin vapor into the mouth4 ,the filling is secured by keeping the bromin solution in a heavy erlenmeyer with a side tubulure such as is used for filtering under pressure4 ,the solutions are mixed in a long tube1 held in a larger vessel1 from which the air is exhausted to secure a minimum radiation of heat4 ,a delicate thermometer graduated in tenths serves to register the rise of temperature4 ,the fat solution is first placed in the test tube1 with care not to pour it down the sides of the tube but to add it by means of a pipette reaching nearly to the bottom4 ,the whole apparatus having been allowed to come to a standard temperature the bromin solution is allowed to run in quickly from the pipette4 ,no stirring is required as the liquids are sufficiently mixed by the addition of the bromin solution4 ,the mercury in the thermometer rapidly rises and is read at its maximum point by means of a magnifying glass4 ,with a thermometer graduated in tenths1 it is easy to read to twentieths of a degree4 ,it is evident that the rise of temperature obtained depends on similar conditions to those mentioned in connection with sulfuric saponification4 ,each system of apparatus must be carefully calibrated under standard conditions and when this is done the comparative rise of temperature obtained with various oils and fats will prove of great analytical use4 ,it is evident that the ratio of this rise of temperature to the iodin number must be determined for every system of apparatus and for every method of manipulation employed1 and no fixed factor can be given that will apply in every case4 ,with the apparatus above described and with the method of manipulation given the following data were obtained for the oils mentioned3 ,rise of temperature4 ,olive oil #bj4e ,refined cottonseed oil #be4g ,sunflowerseed oil #bh4d ,calycanthusseed oil #bi4j ,bromin and chloroform1 when mixed together1 give off heat1 due to the chemical reaction resulting from the substitution of bromin for hydrogen in the chloroform molecule and the formation of hydrobromic acid4 ,for this reason the data obtained1 when chloroform is used as a solvent1 are slightly higher than with carbon tetrachlorid4 ,the use of the latter reagent is therefore to be preferred4 #cbh4 ,haloid ,addition ,numbers4--,many of the glycerids possess the property of combining directly with the haloids and forming thereby compounds in which the haloid1 by simple addition1 has become a part of the molecule4 ,olein is a type of this class of unsaturated glycerids4 ,the process may take place promptly as in the case of bromin or move slowly as with iodin4 ,the quantity of the haloid absorbed is best determined in the residual matter and not by an examination of the fat compound4 ,by reason of the ease with which the amount of free iodin in solution can be determined1 this substance is the one which is commonly employed in analytical operation on fats4 ,in general1 the principle of the operation depends on bringing the fat and haloid together in a proper solution and allowing the addition to take place by simple contact4 ,the quantity of the haloid in the original solution being known1 the amount which remains in solution after the absorption is complete1 deducted from that originally present1 will give the quantity which has entered into combination with the glycerid4 #cbi4 ,hbl's ,process4--,in determining the quantity of iodin which will combine with a fat1 the method first proposed by ,hbl1 or some modification thereof1 is universally employed4#bij ,in the determination of the iodin number of a glycerid it is important that it be accomplished under set conditions and that iodid be always present in large excess4 ,it is only when data are obtained in the way noted that they can be regarded as useful for comparison and determination4 ,many modifications of ,hbl's process have been proposed1 but it is manifestly impracticable to give even a summary of them here4 ,as practiced in the chemical laboratory of the ,agricultural ,department and by the ,association of ,official ,agricultural ,chemists1 it is carried out as follows3#bia 7#a7 ,,preparation ,,of ,,reagents4 7a74 ,iodin ,solution4--,dissolve twenty-five grams of pure iodin in #ejj cubic centimeters of ninety-five per cent alcohol4 ,dissolve thirty grams of mercuric chlorid in #ejj cubic centimeters of ninety-five per cent alcohol4 ,the latter solution1 if necessary1 is filtered1 and then the two solutions mixed4 ,the mixed solution should be allowed to stand twelve hours before using4 7b74 ,decinormal ,sodium ,thiosulfate ,solution4--,dissolve #bd4h grams of chemically pure sodium thiosulfate1 freshly pulverized as finely as possible and dried between filter or blotting paper1 and dilute with water to one liter1 at the temperature at which the titrations are to be made4 7c74 ,starch ,paste4--,one gram of starch is boiled in #bjj cubic centimeters of distilled water for ten minutes and cooled to room temperature4 7d74 ,solution of ,potassium ,iodid4--,one hundred and fifty grams of potassium iodid are dissolved in water and the volume made up to one liter4 7e74 ,solution of ,potassium ,bichromate4--,dissolve #c4hgd grams of chemically pure potassium bichromate in distilled water and make the volume up to one liter at the temperature at which the titrations are to be made4 7#b74 ,,determination4 7a74 ,standardizing the ,sodium ,thiosulfate ,solution4--,place twenty cubic centimeters of the potassium bichromate solution1 to which have been added ten cubic centimeters of the solution of potassium iodid1 in a glass stopper flask4 ,add to this mixture five cubic centimeters of strong hydrochloric acid4 ,allow the solution of sodium thiosulfate to flow slowly into the flask until the yellow color of the liquid has almost disappeared4 ,add a few drops of the starch paste1 and with constant shaking continue to add the sodium thiosulfate solution until the blue color just disappears4 ,the number of cubic centimeters of thiosulfate solution used multiplied by five is equivalent to one gram of iodin4 ,example4--,twenty cubic centimeters of potassium bichromate solution required #af4b sodium thiosulfate2 then #af4b #e #ha number cubic centimeters of thiosulfate solution equivalent to one gram of iodin4 ,then one cubic centimeter thiosulfate solution #j4jabd gram of iodin3 7,theory for decinormal solution of sodium thiosulfate1 one cubic centimeter #j4jabg gram of iodin47 7b74 ,weighing the ,sample4--,about one gram of butter fat is placed in a glass stopper flask1 holding about #cjj cubic centimeters1 with the precautions to be mentioned for weighing the fat for determining volatile acids4 7c74 ,absorption of ,iodin4--,the fat in the flask is dissolved in ten cubic centimeters of chloroform4 ,after complete solution has taken place thirty cubic centimeters of the iodin solution 7#a7 7a7 are added4 ,the flask is now placed in a dark place and allowed to stand1 with occasional shaking1 for three hours4 7d74 ,titration of the ,unabsorbed ,iodin4--,one hundred cubic centimeters of distilled water are added to the contents of the flask1 together with twenty cubic centimeters of the potassium iodid solution4 ,any iodin which may be noticed upon the stopper of the flask should be washed back into the flask with the potassium iodid solution4 ,the excess of iodin is taken up with the sodium thiosulfate solution1 which is run in gradually1 with constant shaking1 until the yellow color of the solution has almost disappeared4 ,a few drops of starch paste are added1 and the titration continued until the blue color has entirely disappeared4 ,toward the end of the reaction the flask should be stoppered and violently shaken1 so that any iodin remaining in solution in the chloroform may be taken up by the potassium iodid solution in the water4 ,a sufficient quantity of sodium thiosulfate solution should be added to prevent a reappearance of any blue color in the flask for five minutes4 7e74 ,setting the ,value of the ,iodin ,solution by the ,thiosulfate ,solution4--,at the time of adding the iodin solution to the fat1 two flasks of the same size as those used for the determination should be employed for conducting the operation described above1 but without the presence of any fat4 ,in every other respect the performance of the blank experiments should be just as described4 ,these blank experiments must be made each time the iodin solution is used4 ,example of ,blank ,determinations4--,thirty cubic centimeters of iodin solution required #df4d cubic centimeters of sodium thiosulfate solution3 ,thirty cubic centimeters of iodin solution required #df4h cubic centimeters of sodium thiosulfate solution3 ,mean1 #df4f cubic centimeters4 ,weight of fat #a4jdgi grams ,quantity of iodin solution used #cj4j cubic centimeters ,thiosulfate equivalent to iodin used #df4f 0 0 ,thiosulfate equivalent to remaining iodin #ad4g 0 0 ,thiosulfate equivalent to iodin absorbed #ca4i 0 0 ,percent of iodin absorbed1 #ca4i #j4jabd #ajj #a4jdgi #cg4ge4 #ccj4 ,character of ,chemical ,reaction4--,the exact nature of the chemical process which takes place in this reaction is not definitely known4 ,hbl supposed that the products formed were chloro-iodid-additive compounds1 and he obtained a greasy product from oleic acid1 to which he ascribed the formula ,c,h,i,cl,o4 ,by others it is thought that chlorin alone may be added to the molecule4#bib ,in general1 it may be said that none of the glycerids capable of absorbing halogens is able to take on a quantity equivalent to theory4#bic ,while the saturated fatty acids 7stearic series7 theoretically are not able to absorb iodin some of them are found to do so to a small degree4 ,it is evident1 therefore1 that it is not possible to calculate the percentage of unsaturated glycerids in a fat from their iodin number alone4 ,according to the data worked out by ,schweitzer and ,lungwitz both addition and substitution of iodin take place during the reaction4#bid ,this fact they determined by titration with potassium iodate and iodid according to the formula #e;,,hi ,,hio #f;,i #f;,h,o4 ,the authors confess that whenever free hydriodic acid is found in the mixture that iodin substitution has taken place and that for each atom of hydrogen eliminated from the fat molecule two atoms of iodin disappear1 one as the substitute and the other in the form of hydriodic acid4 ,when carbon bisulfid or tetrachlorid is used as a solvent no substitution takes place and pure additive compounds are formed4 ,the following process is recommended to secure a pure iodin addition to a glycerid3 ,about one gram or a little less of the oil or fat is placed in a glass stopper flask1 to which are added about seven-tenths of a gram of powdered mercuric chlorid and twenty-five cubic centimeters of a solution of iodin in carbon bisulfid4 ,the stopper is made tight by smearing it with powdered potassium iodid1 tied down1 and the mixture is heated for some time under pressure4 ,by this method it is found that no hydriodic acid is formed1 and hence all the iodin which disappears is added to the molecule of the glycerid4 ,the additive numbers obtained for some oils are appended3 ,time of ,per cent ,per cent ,oil4 heating4 ,temperature4 iodin added4 hbl number4 ,lard oil #cj minutes4 #ej4j #gc4j #gh4d ,cottonseed oil #b hours4 #ej4j #ajc4j #ajf4e ,oleic acid #b 0 #fe4e #ic4h #cca4 ,solution in ,carbon ,tetrachlorid4--,gantter has called attention to the fact that the amount of iodin absorbed by fat does not depend alone upon the proportion of iodin present but also upon the amount of mercuric chlorid in the solution4#bie ,increasing amounts of mercuric chlorid cause uniformly a much greater absorption of the iodin4 ,for this reason he proposes to discard the use of mercuric chlorid altogether for the hbl test and to use a solvent which will at the same time dissolve both the iodin and the fat4 ,for this purpose he uses carbon tetrachlorid4 ,the solutions are prepared as follows3 ,iodin ,solution4--,ten grams of iodin are dissolved in one liter of carbon tetrachlorid4 ,in the preparation of this solution the iodin must not be thrown directly into the flask before the addition of the tetrachlorid4 ,iodin dissolves very slowly in carbon tetrachlorid and the solution is made by placing it in a sufficiently large weighing glass and adding a portion of the carbon tetrachlorid thereto4 ,the solution is facilitated by stirring with a glass rod until the added tetrachlorid is apparently charged with the dissolved iodin4 ,the dissolved portion is then poured into a liter flask1 new portions added to the iodin and this process continued until the iodin is completely dissolved1 and then sufficient additional quantities of the tetrachlorid are added to fill the flask up to the mark4 #ccb4 ,sodium ,thiosulfate ,solution4--,dissolve #ai4ebh grams of pure sodium thiosulfate in #ajjj cubic centimeters of water4 ,for determining the strength of the solution by titration1 the solution of iodin in carbon tetrachlorid and a solution of sodium thiosulfate in water are each placed in a burette4 ,a given volume of the iodin solution is first run into a flask with a glass stopper and afterward the sodium thiosulfate added little by little until1 after a vigorous shaking1 the liquid has only a little color4 ,some solution of starch is then added and shaken until the mixture becomes deep blue4 ,the sodium thiosulfate solution is added drop by drop1 with vigorous shaking after each addition1 until the solution is completely decolorized4 ,if both solutions have been correctly made with pure materials they will be of equal strength2 that is1 ten cubic centimeters of the iodin solution will be exactly decolorized by ten cubic centimeters of the sodium thiosulfate solution4 #ccc4 ,method of ,conducting the ,absorption4--,the quantity of the fat or oil employed should range from #ajj to #bjj milligrams1 according to the absorption equivalent4 ,these quantities should be placed in flasks with glass stoppers in the ordinary way4 ,in the flasks are placed exactly fifty cubic centimeters of the iodin solution equivalent to #ejj milligrams of iodin1 and the flask is then stoppered and shaken until the fat or oil is completely dissolved4 ,in order to avoid the volatilization of the iodin finally1 sufficient water is poured into the flask to form a layer about one millimeter in thickness over the solution containing the iodin and fat4 ,the stopper should be carefully inserted and the flask allowed to stand at rest for fifty hours4 #ccd4 ,estimation of the ,iodin ,number4--,this is determined in the usual way by titration of the amount of iodin left in excess after the absorption as above described4 ,the iodin number is to be expressed by the number of milligrams of iodin which are absorbed by each #ajj milligrams of fat4 ,example4--,one hundred and one milligrams of flaxseed oil were dissolved in fifty cubic centimeters of the carbon tetrachlorid solution of iodin and allowed to stand as above described for fifty hours4 ,at the end of this time1 #db4c cubic centimeters of the sodium thiosulfate solution were required to decolorize the excess of iodin remaining4 ,statement of ,results4--,fifty cubic centimeters of the sodium thiosulfate equal #ejj milligrams of iodin2 therefore1 #db4c cubic centimeters of the thiosulfate solution equal #dbc milligrams of iodin4 ,the difference equals seventy-seven milligrams of iodin absorbed by #aja milligrams of the flaxseed oil4 ,therefore1 the iodin number equivalent and the milligrams of iodin absorbed by #ajj milligrams of flaxseed oil equal #gf4b4 ,it is evident from the above determination that the iodin number of the oil1 when obtained in the manner described1 is less than half that secured by the usual hbl process4 ,since the solvent employed1 however1 is more stable than chloroform when in contact with iodin or bromin1 the proposed variation is one worthy of the careful attention of analysts4 ,mc,ilhiney has called especial attention to the low numbers given by the method of ,gantter1 and from a study of the data obtained concludes that iodin alone will not saturate glycerids1 no matter what the solvents may be4#bif ,it is clear1 therefore1 that the process of ,gantter cannot give numbers which are comparable with those obtained by the usual iodin method4 ,any comparative value possessed by the data given by the process of ,gantter must be derived by confining it to the numbers secured by the carbon tetrachlorid process alone4 #cce4 ,substitution of ,iodin ,monochlorid for ,hbl's ,reagent4--,ephraim has shown that iodin monochlorid may be conveniently substituted for the hbl reagent with the advantage that it can be safely used at once1 while the hbl reagent undergoes somewhat rapid changes when first prepared4 ,the present disadvantage of the process is found in the fact that the iodin monochlorid of commerce is not quite pure and each new lot requires to be titrated for the determination of its purity4 ,the reagent is prepared of such a strength as to contain #af4be grams of iodin monochlorid per liter4 ,the solvent used is alcohol4 ,the operation is carried out precisely as in the hbl method1 substituting the alcoholic solution of iodin monochlorid for the iodin reagent proposed by ,hbl4#big ,if the iodin monochlorid solution1 after acting on the oil1 be titrated without previous addition of potassium iodid a new value is obtained1 the chloriodin number4 ,in titrating1 the sodium thiosulfate is added until the liquid1 which is made brown by the separated iodin1 becomes yellow4 ,at this point the solution is diluted1 starch paste added1 and the titration completed4 #ccf4 ,preservation of the ,hbl ,reagent4--,to avoid the trouble due to changes in the strength of ,hbl's reagent1 ,mahle adds hydrochloric acid to it at the time of its preparation4#bih ,the reagent is prepared as follows3 ,twenty-five grams of iodin dissolved in a quarter of a liter of ninety-five per cent alcohol are mixed with the same quantity of mercuric chlorid in #bjj cubic centimeters of alcohol1 the same weight of hydrochloric acid of #a4ai specific gravity added and the volume of the mixture completed to half a liter with alcohol4 ,after five days such a solution gave1 on titration1 #di4ah instead of #di4ca grams per liter of iodin4 ,it will be observed that this solution is double the usual strength1 but this does not influence the accuracy of the analytical data obtained4 ,it appears that the hbl number is not1 therefore1 an iodin number1 but expresses the total quantity of iodin1 chlorin and oxygen absorbed by the fat during the progress of the reaction4 #ccg4 ,bromin ,addition ,number4--,in the process of ,hbl and others an attempt is made to determine the quantity of a halogen1 e4g41 iodin1 which the oil1 fat or resin will absorb under certain conditions4 ,the numbers obtained1 however1 represent this absorption only approximately1 because the halogen may disappear through substitution as well as absorption4 ,whether or not a halogen is added1 i4 e41 absorbed or substituted1 may be determined experimentally4 ,the principle on which the determination depends rests on the fact that a halogen1 e4 g41 bromin1 forms a molecule of hydrobromic acid for every atom of bromin substituted1 while in a simple absorption of the halogen no such action takes place4 ,if1 therefore1 bromin be brought into contact with a fat1 oil or resin1 the determination of the quantity of hydrobromic acid formed will rigidly determine the quantity of bromin substituted during the reaction4 ,if this quantity be deducted from the total bromin which has disappeared1 the relative quantities of the halogen added and substituted are at once determined4 ,in the method of ,mc,ilhiney#bii bromin is used instead of iodin because the addition figures of iodin are in general much too low4 ,the ,reagents4--,the following solutions are employed3 #a4 ,one-third normal bromin dissolved in carbon tetrachlorid3 #b4 ,one-tenth normal sodium thiosulfate3 #c4 ,one-tenth normal potassium hydroxid4 ,the ,manipulation4--,from a quarter to one gram of the fat1 oil or resin1 is dissolved in ten cubic centimeters of carbon tetrachlorid in a dry bottle of #ejj cubic centimeters capacity1 provided with a well-ground glass stopper4 ,an excess of the bromin solution is added1 the bottle tightly stoppered1 well shaken and placed in the dark4 ,at the end of eighteen hours the bottle is placed in a freezing mixture and cooled until a partial vacuum is formed4 ,a piece of wide rubber tubing an inch and a half long is slipped over the lip of the bottle so as to form a well about the stopper4 ,this well having been filled with water the stopper is lifted and the water is sucked into the bottle absorbing all the hydrobromic acid which has been formed4 ,the well should be kept filled with water1 as it is gradually taken in until in all twenty-five cubic centimeters have been added4 ,the bottle is next well shaken and from ten to twenty cubic centimeters of a twenty per cent potassium iodid solution added4 ,the excess of bromin liberates a corresponding amount of iodin1 which is determined by the thiosulfate solution in the usual way1 after adding about seventy-five cubic centimeters of water4 ,the total bromin which has disappeared is then calculated from the data obtained1 the strength of the original bromin solution having been previously determined4 ,the contents of the bottle are next transferred to a separatory funnel1 the aqueous portion separated1 filtered through a linen filter1 a few drops of thiosulfate solution added1 if a blue color persist1 and the free hydrobromic acid determined by titration with potassium hydroxid1 using methyl orange as indicator4 ,the end reaction is best observed by placing the solution in a porcelain dish1 adding the alkali in slight excess1 and titrating back with tenth-normal hydrochloric acid until the pink tint is perceived4 ,from the number of cubic centimeters of alkali used the amount of bromin present as hydrobromic acid is calculated1 and this expressed as percentage gives the bromin substitution figure4 ,the bromin substitution figure multiplied by two and subtracted from the total absorption gives the addition figure4 ,following are the data for some common substances3 ,total bromin absorption in ,bromin addition ,bromin substitution ,substance4 eighteen hours4 figure4 figure4 ,rosin #bab4gj #j4jj #ajf4ce ,raw linseed oil #ajb4hh #ajb4hh #jj4jj ,boiled 0 0 #ajc4ib #ajc4ib #jj4jj ,salad cotton 0 #fe4ed #fd4bf #j4fd ,sperm 0 #ef4fj #ed4eb #a4jd ,by the process just described it is possible to detect mixtures of rosins and rosin oils with animal and vegetable oils4 ,in this respect it possesses undoubted advantages over the older methods4 #cch4 ,method ,of ,hehner4--,the absorption of bromin which takes place when unsaturated fats are brought into contact with that reagent was made the basis of an analytical process1 proposed by ,allen as long ago as #ahhj4cjj ,in the further study of the phenomena of bromin absorption1 as indicated by ,mc,ilhiney1 ,hehner modified the method as indicated below4#cja ,from one to three grams of the sample are placed in a tared wide-mouthed flask and dissolved in a little chloroform4 ,bromin is added to the solution1 drop by drop1 until it is in decided excess4 ,the flask is placed on a steam-bath and heated until the greater part of the bromin is evaporated1 when some more chloroform is added and the heating continued until all the free bromin has escaped4 ,the flask is put in a bath at #abe and dried to constant weight4 ,a little acrolein and hydrobromic acid escape during the drying and the residue may be colored1 or a heavy bromo oil be obtained4 ,the gain in weight represents the bromin absorbed4 ,the bromin number may be converted into the iodin number by multiplying by #a4ehge4cjb ,illustration3 ,,fig4 #ajj4--,,olein ,,tube4 #cci4 ,halogen ,absorption and ,addition of ,fat ,acids4--,instead of employing the natural glycerids for determining the degree of action with the halogens the acids may be separated by some of the processes of saponification hereafter described and used as directed for the glycerids themselves4 ,it is doubtful if any practical advantage arises from this variation of the process4 ,if the fat acids be separated1 however1 it is possible to get some valuable data from the halogen absorption of the fractions4 ,theoretically the stearic series of acids would suffer no change in contact with halogens while the oleic series is capable of a maximum absorptive and additive action4 ,on this fact is based a variation of the iodin process in which an attempt is made to separate the oleic acid from its congeners and to apply the halogen to the separated product4 ,the method of separation devised by ,muter is carried out as follows3#cjc ,the separatory or olein tube consists of a wide burette stem1 provided with a lateral stopcock1 and drawn out below to secure a clamp delivery tube1 and at the top expanded into a bulb closed with a ground glass stopper1 as shown in ,fig4 #ajj4 ,forty cubic centimeters of liquid are placed in the tube and the surface is marked #j4 ,above this the graduation is continued in cubic centimeters to #bej1 which figure is just below the bulb at the top4 ,the process of analysis is conducted as follows3 ,about three grams of the oil or fat are placed in a flask1 with fifty cubic centimeters of alcoholic potash lye1 containing enough potassium hydroxid to ensure complete saponification4 ,the flask is closed and heated on a water-bath until saponification is complete4 ,the pressure flask to be described hereafter may be conveniently used4 ,after cooling1 the excess of alkali is neutralized with acetic acid in presence of phenolphthalien and then alcoholic potash added until a faint pink color is produced4 ,in a large porcelain dish place #bjj cubic centimeters of water and thirty of a ten per cent solution of lead acetate and boil4 ,pour slowly1 with constant stirring1 into the boiling liquid the soap solution prepared as above described1 and allow to cool1 meanwhile continuing the stirring4 ,at the end1 the liquid remaining is poured off and the solid residue washed with hot water by decantation4 ,the precipitate of lead salts is finally removed from the dish into a stoppered bottle1 the dish washed with pure ether1 the washings added to the bottle together with enough ether to make the total volume thereof #abj cubic centimeters4 ,the closed bottle is allowed to stand for twelve hours with occasional shaking1 by which time the lead oleate will have been completely dissolved4 ,the insoluble lead salts are next separated by filtration1 and the filtrate collected in the olein tube4 ,the washing is accomplished by ether and1 to avoid loss1 the funnel is covered with a glass plate4 ,the ethereal solution of lead oleate is decomposed by dilute hydrochloric acid1 using about forty cubic centimeters of a mixture containing one part of strong acid to four of water4 ,the olein tube is closed and shaken until the decomposition is complete1 which will be indicated by the clearing of the ethereal solution4 ,the tube is allowed to remain at rest until the liquids separate and the aqueous solution is run out from the pinch-cock at the lower end4 ,the residue is washed with water by shaking1 the water drawn off as just described1 and the process continued until all acidity is removed4 ,water is then added until the separating plane between the two liquids is at the zero of the graduation1 and enough ether added to make the ethereal solution of a desired volume1 say #bjj cubic centimeters4 ,after well mixing1 the ethereal solution or an aliquot part thereof1 e4g41 fifty cubic centimeters1 is removed by the side tubulure and nearly the whole of the ether removed from the portion by distillation4 ,to the residue are added fifty cubic centimeters of pure alcohol and the solution is titrated for oleic acid with decinormal sodium hydroxid solution4 ,each cubic centimeter of the hydroxid solution used is equivalent to #j4jbhb gram of oleic acid4 ,the total quantity of oleic acid contained in the amount of fat used is readily calculated from the data obtained4 ,to determine the iodin absorption of the free acid another measured quantity of the ethereal solution containing as nearly as possible half a gram of oleic acid1 is withdrawn from the olein tube1 and the ether removed in an atmosphere of pure carbon dioxid4 ,to the residue1 without allowing it to come in contact with the air1 fifty cubic centimeters of ,hbl's reagent are added and the flask put aside in the dark for twelve hours4 ,at the end of this time thirty-five cubic centimeters of a ten per cent solution of potassium iodid are added1 the contents of the flask made up to a quarter of a liter with water1 fifteen cubic centimeters of chloroform added1 and the excess of iodin titrated in the way already described4 ,the percentage of iodin absorbed is calculated as already indicated4 ,lane has proposed a more rapid process for the above determination4#cjd ,the lead soaps are precipitated in a large erlenmeyer and cooled rapidly in water1 giving the flask meanwhile a circular motion which causes the soaps to adhere to its walls4 ,wash with hot water1 rinsing once with alcohol1 add #abj cubic centimeters of ether1 attach a reflux condenser1 and boil until the lead oleate is dissolved1 cool slowly1 to allow any lead stearate which has passed into solution to separate1 and filter into the olein tube4 ,the rest of the operation is conducted as described above4 ,the percentage of oleic acid and its iodin absorption in the following glycerids are given in the table below3 ,cottonseed oil4 ,lard4 ,peanut oil4 ,per cent oleic acid #ge4af #fd4ae #gi4hd ,per cent iodin absorbed #ada4if #ii4dh #aad4jj #cdj4 ,saponification4--,in many of the analytical operations which are conducted on the glycerids it is necessary to decompose them4 ,when this is accomplished by the action of a base which displaces the glycerol from its combination with the fat acids1 the resulting salts are known as soaps and the process is named saponification4 ,in general use the term saponification is applied1 not only strictly1 as above defined1 but also broadly1 including the setting free of the glycerol either by the action of strong acids or by the application of superheated steam4 ,in chemical processes the saponification of a glycerid is almost always accomplished by means of soda or potash lye4 ,this may be in aqueous or alcoholic solution and the process is accomplished either hot or cold1 in open vessels or under pressure4 ,it is only important that the alkali and glycerid be brought into intimate contact4 ,the rate of saponification is a function of the intimacy of contact1 the nature of the solvent and the temperature4 ,for chemical purposes1 it is best that the decomposition of the glycerid be accomplished at a low temperature and for most samples this is secured by dissolving the alkali in alcohol4 ,in respect of solvents1 that one would be most desirable1 from theoretical considerations1 which acts on both the glycerids and alkalies4 ,in the next rank would be those which dissolve one or the other of the materials and are easily miscible1 as1 for instance1 carbon tetrachlorid for the glycerid and alcohol for the alkali4 ,as a rule1 the glycerid is not brought into solution before the saponification process is commenced4 ,instead of using an alcoholic solution of sodium or potassium hydroxid the sodium or potassium alcoholate may be employed1 made by dissolving metallic sodium or potassium in alcohol4 ,it is probable1 however1 that a little water is always necessary to complete the process4 ,if a fat be dissolved in ether and treated with sodium alcoholate1 a granular deposit of soap is soon formed and the saponification is completed in twenty-four hours4 ,as much as #aej grams of fat can be saponified with ten grams of metallic sodium dissolved in #bej cubic centimeters of absolute alcohol4#cje ,for practical purposes the alcoholic solution of the hydroxid is sufficient4 ,the chemical changes which fats undergo on saponification are of a simple kind4 ,when the process is accomplished by means of alkalies1 the alkaline base takes the place of the glycerol as indicated in the following equation3 ,triolein #hhd4 ,potassium hydroxid #afh4 ,c,h7,o4,c,h,o7 #c,,koh ,potassium oleate #ifj4 ,glycerol #ib4 7,,ko4,c,h,o7 ,c,h7,,oh74 ,the actual changes which take place in ordinary saponification are not so simple1 however1 since natural glycerids are mixtures of several widely differing fats1 each of which has its own rate of decomposition4 ,palmitin and stearin1 for instance1 are saponified more readily than olein and some of the saponifiable constituents of resins and waxes are extremely resistant to the action of alkalies4 ,the above equation may be regarded as typical for saponification in aqueous or alcoholic solutions in open dishes or under pressure4 ,if the alkali used be prepared by dissolving metallic sodium or potassium in absolute alcohol 7sodium alcoholate or ethoxid7 the reaction which takes place is probably represented by the equation given below3 ,c,h7,o4,c,h,o7 #c;,c,h4,o,na ,c,h7,o,na7 #c;,c,h,o4,o4,c,h1 in which it is seen that complete saponification cannot occur without the absorption of some water1 by which the sodium glyceroxid is converted into glycerol and sodium hydroxid1 the latter compound eventually uniting with the ethyl ether of the fat acid4#cjf ,glycerids are decomposed when heated with water under a pressure of about sixteen atmospheres or when subjected to a current of superheated steam at #bjj4 ,the reaction consists in the addition of the elements of water1 whereby the glyceryl radicle is converted into free glycerol and the fat acid is set free4 ,the chemical change which ensues is shown below3 ,c,h7,o4,c,h,o7 #c;,h,o #c;,c,h,o ,c,h7,,oh74 ,the details of saponification with sulfuric acid are of no interest from an analytical point of view4#cjg #cda4 ,saponification in an ,open ,dish4--,the simplest method of saponifying fats is to treat them with the alkaline reagent in an open dish4 ,in all cases the process is accelerated by the application of heat4 ,vigorous stirring also aids the process by securing a more intimate mixture of the ingredients4 ,this method of decomposing glycerids1 however1 is not applicable in cases where volatile ethers may be developed4 ,these ethers may escape saponification and thus prevent the formation of the maximum quantity of soap4 ,while not suited to exact quantitive work1 the method is convenient in the preparation of fat acids which are to be the basis of subsequent analytical operations1 as1 for instance1 in the preparation of fat acids for testing with silver nitrate4 ,large porcelain dishes are conveniently used and the heat is applied in any usual way1 with care to avoid scorching the fat4 #cdb4 ,saponification under ,pressure4--,the method of saponification which has given the best satisfaction in my work and which has been adopted by the ,association of ,official ,agricultural ,chemists is described below4#cjh ,reagents4--,the reagents employed are a solution of pure potash containing #ajj grams of the hydroxid dissolved in fifty-eight grams of recently boiled distilled water1 alcohol of approximately ninety-five per cent strength redistilled over caustic soda1 and sodium hydroxid solution prepared as follows3 ,one hundred grams of sodium hydroxid are dissolved in #ajj cubic centimeters of distilled water4 ,the caustic soda should be as free as possible from carbonates1 and be preserved from contact with the air4 ,apparatus4--,a saponification flask2 it has a round bottom and a ring near the top1 by means of which the stopper can be tied down4 ,the flask is arranged for heating as shown in ,fig4 #aja4 ,a pipette graduated to deliver forty cubic centimeters is recommended as being more convenient than a burette for measuring the solutions3 ,a pipette with a long stem graduated to deliver #e4ge cubic centimeters at #ej4 ,manipulation4--,the fat to be examined should be melted and kept in a dry warm place at about #fj for two or three hours1 until the water has entirely separated4 ,the clear supernatant fat is poured off and filtered through a dry filter paper in a jacket funnel containing boiling water4 ,should the filtered fat1 in a fused state1 not be perfectly clear1 it must be filtered a second time4 ,the final drying is accomplished at #ajj in a thin layer in a flat bottom dish1 in partial vacuum or an atmosphere of inert gas4 ,the saponification flasks are prepared by thoroughly washing with water1 alcohol1 and ether1 wiping perfectly dry on the outside1 and heating for one hour at the temperature of boiling water4 ,the hard flasks used in moist combustions with sulfuric acid for the determination of nitrogen are well suited for this work4 ,the flasks should be placed in a tray by the side of the balance and covered with a silk handkerchief until they are perfectly cool4 ,they must not be wiped with a silk handkerchief within fifteen or twenty minutes of the time they are weighed or else the electricity developed will interfere with weighing4 ,the weight of the flasks having been accurately determined1 they are charged with the melted fat in the following way3 ,illustration3 ,,fig4 #aja4--;,,apparatus ,,for ,,saponifying ,,under ,,pressure4 ,the pipette with a long stem1 marked to deliver #e4ge cubic centimeters1 is warmed to a temperature of about #ej4 ,the fat1 having been poured back and forth once or twice into a dry beaker in order to thoroughly mix it1 is taken up in the pipette1 the nozzle of the pipette having been previously wiped to remove any externally adhering fat1 is carried to near the bottom of the flask and #e4ge cubic centimeters of fat allowed to flow into the flask4 ,after the flasks have been charged in this way they should be re-covered with the silk handkerchief and allowed to stand for fifteen or twenty minutes1 when they are again weighed4 #cdc4 ,methods of ,saponification4--,in the ,presence of ,alcohol4--,ten cubic centimeters of ninety-five per cent alcohol are added to the fat in the flask1 and then two cubic centimeters of the sodium hydroxid solution4 ,a soft cork stopper is inserted and tied down with a piece of twine4 ,the saponification is completed by placing the flask upon the water or steam-bath4 ,the flask during the saponification1 which should last one hour1 should be gently rotated from time to time1 being careful not to project the soap for any distance up its sides4 ,at the end of an hour the flask1 after having been cooled to near the room temperature1 is opened4 ,without the ,use of ,alcohol4--,to avoid the danger of loss from the formation of ethers1 and the trouble of removing the alcohol after saponification1 the fat may be saponified with a solution of caustic potash in a closed flask without using alcohol4 ,the operation is carried on exactly as indicated above for saponification in the presence of alcohol1 using potassium instead of sodium hydroxid solution4 ,for the saponification1 use two cubic centimeters of the potassium hydroxid solution which are poured on the fat after it has solidified in the flask4 ,great care must be taken that none of the fat be allowed to rise on the sides of the saponifying flask to a point where it cannot be reached by the alkali4 ,during the process of saponification the flask can only be very gently rotated in order to avoid the difficulty mentioned4 ,this process is not recommended with any apparatus except a closed flask with round bottom4 ,potash is used instead of soda so as to form a softer soap and thus allow a more perfect saponification4 ,the saponification may also be conducted as follows3 ,the alkali and fat in the melted state are shaken vigorously in the saponification flask until a complete emulsion is secured4 ,the rest of the operation is then conducted as above4 #cdd4 ,saponification in the ,cold4--,by reason of the danger of loss from volatile ethers in the hot alcoholic saponification1 a method for successfully conducting the operation in the cold is desirable4 ,such a process has been worked out by ,henriques4#cji ,it is based upon the previous solution of the fat in petroleum ether1 in which condition it is so easily attacked by the alcoholic alkali as to make the use of heat during the saponification unnecessary4 ,the process is conveniently conducted in a porcelain dish covered with a watch glass4 ,five grams of the fat are dissolved in twenty-five cubic centimeters of petroleum ether and treated with an equal quantity of four per cent alcoholic soda lye4 ,the process of saponification begins at once and is often indicated by the separation of sodium salts4 ,it is best to allow the action to continue over night and1 with certain difficultly saponifiable bodies1 such as wool fat and waxes1 for twenty-four hours4 ,in the case of butter fat an odor of butyric ether may be perceived at first but it soon disappears4 ,after the saponification is complete1 the excess of alkali is determined by titration in the usual way with set hydrochloric acid1 using phenolphthalien as indicator4 ,for the determination of volatile acids1 the mixture1 after saponification is complete1 is evaporated rapidly to dryness1 the solid matter being reduced to powder with a glass rod1 after which it is transferred to a distilling flask and the volatile acids secured by the usual processes4 ,in comparison with the saponification and reichert-meissl numbers obtained with hot alcoholic potash1 the numbers given by the cold process are found to be slightly higher with those fats which give easily volatile ethers4 ,on account of the simplicity of the process and the absence of danger of loss from ethers1 it is to be recommended instead of the older methods in case a more extended trial of it should establish the points of excellence claimed above4 #cde4 ,saponification ,value4--,the number of milligrams of potassium hydroxid required to completely saturate one gram of a fat is known as the saponification value of the glycerid4 ,the process of determining this value1 as worked out by ,koettstorfer and modified in the laboratory of the ,department of ,agriculture1 is as follows3#caj ,the saponification is accomplished with the aid of potassium hydroxid and in the flask and manner described in the preceding paragraph4 ,about two grams of the fat will be found a convenient quantity4 ,great care must be exercised in measuring the alkaline solution1 the same pipette being used in each case and the same time for draining being allowed in every instance4 ,blanks are always to be conducted with each series of examinations4 ,as soon as the saponification is complete1 the flask is removed from the bath1 allowed to cool and its contents are titrated with seminormal hydrochloric acid and phenolphthalien as indicator4 ,the number expressing the saponification value is obtained by subtracting the number of cubic centimeters of seminormal hydrochloric acid required to neutralize the alkali after saponification from that required to neutralize the alkali of the blank determinations1 multiplying the result by #bh4jf and dividing the product by the number of grams of fat employed4 ,example4--,weight of sample of fat used #a4ecb grams3 ,number of cubic centimeters half normal hydrochloric acid required to saturate blank1 #bb4e3 ,number of cubic centimeters of half normal hydrochloric acid required to saturate the alkali after saponification #ab4j3 ,difference1 #aj4e cubic centimeters3 ,then #aj4ej #bh4jf #a4ecb #aib4c4 ,this latter number represents the saponification value of the sample4 #cdf4 ,saponification ,equivalent4--,allen defines the saponification equivalent as the number of grams of fat saponified by one equivalent1 viz41 #ef4a grams of potassium hydroxid4#caa ,the saponification equivalent is readily calculated from the saponification value using it as a divisor and #efajj as a dividend4 ,conversely the saponification value may be obtained by dividing #efajj by the saponification equivalent4 ,no advantage is gained by the introduction of a new term so nearly related to saponification value4 #cdg4 ,saponification ,value of ,pure ,glycerids4--,the theoretical saponification values of pure glycerids are given in the following table4#cab ,molecular ,saponification ,name4 ,symbol4 weight4 value4 ,butyrin ,c,h7,o4,c,h,o7 #cjb #eeg4c ,valerin ,c,h7,o4,c,h,o7 #cdd #dhi4b ,caproin ,c,h7,o4,c,h,o7 #chf #dch4c ,caprin ,c,h7,o4,c,h,o7 #eed #cje4j ,laurin ,c,h7,o4,c,h,o7 #fch #bfc4h ,myristin ,c,h7,o4,c,h,o7 #gbb #bcc4a ,palmitin ,c,h7,o4,c,h,o7 #hjf #bjh4h ,stearin ,c,h7,o4,c,h,o7 #hij #ahi4a ,olein ,c,h7,o4,c,h,o7 #hhd #aij4d ,linolein ,c,h7,o4,c,h,o7 #hgh #aia4g ,ricinolein ,c,h7,o4,c,h,o7 #icb #ahj4f ,euricin ,c,h7,o4,c,h,o7 #ajeb #afj4j ,from the above table it is seen that in each series of glycerids the saponification equivalent falls as the molecular weight rises4 #cdh4 ,acetyl ,value4--,hydroxy acids and alcohols1 when heated with glacial acetic acid1 undergo a change which consists in substituting the radicle of acetic acid for the hydrogen atom of the alcoholic hydroxyl group4 ,this change is illustrated by the equations below3#cac ,for a ,fat ,acid3 ,ricinoleic acid4 ,acetic anhydrid4 ,c,h7,,oh74,,cooh 7,c,h,o7,o ,acetyl-ricinoleic acid4 ,acetic acid4 ,c,h7,o4,c,h,o7,,cooh ,,hc,h,o4 ,for an ,alcohol3 ,cetyl alcohol4 ,acetic anhydrid4 ,cetyl acetate4 ,acetic acid4 ,c,h4,,oh 7,c,h,o7,o ,c,h4,c,h,o ,,hc,h,o4 ,determination4--,the method of determining the acetyl value of a fat or alcohol has been described by ,benedikt and ,ulzer4#cad ,the operation is conducted on the fat acids and not on the glycerids containing them4 ,the insoluble fat acids are prepared as directed in paragraph #cdj4 ,from twenty to fifty grams of the fat acids are boiled with an equal volume of acetic anhydrid1 in a flask with a reflux condenser1 for two hours4 ,the contents of the flask are transferred to a larger vessel of about one liter capacity1 mixed with half a liter of water and boiled for half an hour4 ,to prevent bumping1 some bubbles of carbon dioxid are drawn through the liquid by means of a tube drawn out to a fine point and extending nearly to the bottom of the flask4 ,the liquids are allowed to separate into two layers and the water is removed with a syphon4 ,the oily matters are treated several times with boiling water until the acetic acid is all washed out4 ,the acetylated fat acids are filtered through a dry hot jacket filter and an aliquot part1 from three to five grams1 is dissolved in absolute alcohol4 ,after the addition of phenolphthalien the mixture is titrated as in the determination of the saponification value4 ,the acid value thus obtained is designated as the acetyl acid value4 ,a measured quantity of alcoholic potash1 standardized by seminormal hydrochloric acid1 is added1 the mixture boiled and the excess of alkali determined by titration4 ,the quantity of alkali consumed in this process measures the acetyl value4 ,the sum of the acetyl acid and the acetyl values is the acetyl saponification value4 ,the acetyl value is therefore equal to the difference of the saponification and acid values of the acetylated fat acids4 ,in other words1 the acetyl value indicates the number of milligrams of potassium hydroxid required to neutralize the acetic acid obtained by the saponification of one gram of the acetylated fat acids4 ,example4--,a portion of the fat acids acetylated as described1 weighing #c4cgi grams1 is exactly neutralized by #ag4b cubic centimeters of seminormal potassium hydroxid solution1 corresponding to #ag4b #j4jbhje #j4dhbe gram of the hydroxid1 hence #j4dhbe #ajjj #c4cgi #adb4h1 the acetyl acid value of the sample4 ,after the addition of #cb4h cubic centimeters more of the seminormal potash solution1 the mixture is boiled to saponify the acetylated fat acids4 ,the residual potash requires #ad4b cubic centimeters of seminormal hydrochloric acid4 ,the quantity of potash required for the acetic acid is therefore #cb4h - #ad4c #ah4e cubic centimeters or #ah4e #j4jbhje #j4eahi gram of potassium hydroxid4 ,then #j4eahi #ajjj #c4cgi #aec4f acetyl value of sample4 ,the sum of these two values1 viz41 #adb4h and #aec4f is #bif4d1 which is the acetyl saponification value of the sample4 ,as with the iodin numbers1 however1 it is also found that acids of the oleic series give an acetyl value when treated as above1 and it has been proposed by ,lewkowitsch to determine1 in lieu of the data obtained1 the actual quantity of acetic acid absorbed by fats4#cae ,this is accomplished by saponifying the acetylated product with alcoholic potash and determining the free acetic acid by distillation1 in a manner entirely analogous to that used for estimating volatile fat acids described further on4 ,the rle which the acetyl value plays in analytical determinations is interesting1 but the data it gives are not to be valued too highly4 #cdi4 ,determination of ,volatile ,fat ,acids4--,the fat acids which are volatile at the temperature of boiling water1 consist chiefly of butyric and its associated acids occurring in the secretions of the mammary glands4 ,among vegetable glycerids cocoanut oil is the only common one which has any notable content of volatile acids4 ,the boiling points of the above acids1 in a pure state1 are much higher than the temperature of boiling water2 for instance1 butyric acid boils at about #afb4 ,by the expression volatile acids1 in analytical practice1 is meant those which are carried over at #ajj1 or a little above1 with the water vapor1 whatever be their boiling point4 ,the great difficulty of removing the volatile from the non-volatile fat acids has prevented the formulation of any method whereby a sharp and complete separation can be accomplished4 ,the analyst1 at the present time1 must be content with some approximate process which1 under like conditions1 will give comparable results4 ,instead1 therefore1 of attempting a definite determination1 he confines his work to securing a partial separation and in expressing the degree of volatile acidity in terms of a standard alkali4 ,to this end1 a definite weight of the fat is saponified1 the resulting soap decomposed with an excess of fixed acid1 and a definite volume of distillate collected and its acidity determined by titration with decinormal alkali4 ,the weight of fat operated on is either two and a half#caf or five grams4#cag ,numerous minor variations have been proposed in the process1 the most important of which is in the use of phosphoric instead of sulfuric acid in the distillation4 ,an extended experience with both acids has shown that no danger is to be apprehended in the use of sulfuric acid and that on the whole it is to be preferred to phosphoric4#cah ,the process as used in this laboratory and as adopted by the official agricultural chemists is conducted as follows3#cai #cej4 ,removal of the ,alcohol4--,the saponification is accomplished in the manner already described1 7#cda-cdd7 and when alcoholic potash is used proceed as follows3 ,the stopper having been laid loosely in the mouth of the flask1 the alcohol is removed by dipping the flask into a steam-bath4 ,the steam should cover the whole of the flask except the neck4 ,after the alcohol is nearly removed1 frothing may be noticed in the soap1 and to avoid any loss from this cause or any creeping of the soap up the sides of the flask1 it should be removed from the bath and shaken to and fro until the frothing disappears4 ,the last traces of alcohol vapor may be removed from the flask by waving it briskly1 mouth down1 to and fro4 ,dissolving the ,soap4--,after the removal of the alcohol the soap should be dissolved by adding #ajj cubic centimeters of recently boiled distilled water1 or eighty cubic centimeters when aqueous potassium hydroxid has been used for saponification1 and warming on the steam-bath1 with occasional shaking1 until the solution of the soap is complete4 ,setting free the ,fat ,acids4--,when the soap solution has cooled to about #fj or #gj1 the fat acids are separated by adding forty cubic centimeters of dilute sulfuric acid solution containing twenty-five grams of acid in one liter1 or sixty cubic centimeters when aqueous potassium hydroxid has been used for saponification4 ,melting the ,fat ,acid ,emulsion4--,the flask is restoppered as in the first instance and the fat acid emulsion melted by replacing the flask on the steam-bath4 ,according to the nature of the fat examined1 the time required for the fusion of the fatty acid emulsions may vary from a few minutes to several hours4 ,the ,distillation4--,after the fat acids are completely melted1 which can be determined by their forming a transparent1 oily layer on the surface of the water1 the flask is cooled to room temperature1 and a few pieces of pumice stone added4 ,the pumice stone is prepared by throwing it1 at a white heat1 into distilled water1 and keeping it under water until used4 ,the flask is connected with a glass condenser1 ,fig4 #ajb1 slowly heated with a naked flame until ebullition begins1 and then the distillation continued by regulating the flame in such a way as to collect #aaj cubic centimeters of the distillate in1 as nearly as possible1 thirty minutes4 ,the distillate should be received in a flask accurately marked at #aaj cubic centimeters4 ,illustration3 ,,fig4 #ajb4--;,,apparatus ,,for ,,the ,,distillation ,,of ,,volatile ,,acids4 ,titration of the ,volatile ,acids4--,the #aaj cubic centimeters of distillate1 after thorough mixing1 are filtered through perfectly dry filter paper1 #ajj cubic centimeters of the filtered distillate poured into a beaker holding about a quarter of a liter1 half a cubic centimeter of phenolphthalien solution added and decinormal barium hydroxid solution run in until a red color is produced4 ,the contents of the beaker are then returned to the measuring flask to remove any acid remaining therein1 poured again into the beaker1 and the titration continued until the red color produced remains apparently unchanged for two or three minutes1 ,the number of cubic centimeters of decinormal barium hydroxid solution required should be increased by one-tenth to represent the entire distillate4 ,the number thus obtained expresses1 in cubic centimeters of decinormal alkali solution1 the volatile acidity of the sample4 ,in each case blank distillations of the reagents used should be conducted under identical conditions1 especially when alcoholic alkali is used for saponification4 ,it is difficult to secure alcohol which will not yield a trace of volatile acid in the conditions named4 ,the quantity of decinormal alkali required to neutralize the blank distillate is to be deducted from that obtained with the sample of fat4 #cea4 ,determination of ,soluble and ,insoluble ,fat ,acids4--,the volatile fat acids are more or less soluble in water1 while those which are not distillable in a current of steam are quite insoluble4 ,it is advisable1 therefore1 to separate these two classes of fat acids1 and the results thus obtained are perhaps more decidedly quantitive than are given by the distillation process just described4 ,the methods used for determining the percentage of insoluble acids are essentially those of ,hehner4#cbj ,many variations of the process have been proposed1 especially in respect of the soluble acids4#cba ,the process1 as conducted in this laboratory and approved by the ,association of ,official ,agricultural ,chemists1 is as follows3 ,preparation of ,reagents4--,sodium ,hydroxid ,solution4--,a decinormal solution of sodium hydroxid is used4 ,each cubic centimeter contains #j4jjdj gram of sodium hydroxid and neutralizes #j4jjhh gram of butyric acid 7,c,h,o74 ,alcoholic ,potash ,solution4--,dissolve forty grams of good caustic potash in one liter of ninety-five per cent alcohol redistilled over caustic potash or soda4 ,the solution must be clear and the potassium hydroxid free from carbonates4 ,standard ,acid ,solution4--,prepare accurately a half normal solution of hydrochloric acid4 ,indicator4--,dissolve one gram of phenolphthalien in #ajj cubic centimeters of ninety-five per cent alcohol4 ,determination4--,soluble ,acids4--,about five grams of the sample are placed in the saponification flask already described1 fifty cubic centimeters of the alcoholic potash solution added1 the flask stoppered and placed in the steam-bath until the fat is entirely saponified4 ,the operation may be facilitated by occasional agitation4 ,the alcoholic potash is always measured with the same pipette and uniformity further secured by allowing it to drain the same length of time 7thirty seconds74 ,two or three blank experiments are conducted at the same time4 ,in from five to thirty minutes1 according to the nature of the fat1 the liquid will appear perfectly homogeneous and1 when this is the case1 the saponification is complete and the flask is removed and cooled4 ,when sufficiently cool1 the stopper is removed and the contents of the flask rinsed with a little ninety-five per cent alcohol into an erlenmeyer1 of about #bjj cubic centimeters capacity1 which is placed on the steam-bath together with the blanks until the alcohol is evaporated4 ,the blanks are titrated with half normal hydrochloric acid1 using phenolphthalien as indicator1 and one cubic centimeter more of the half normal hydrochloric acid than is required to neutralize the potash in the blanks is run into each of the flasks containing the fat acids4 ,the flask is connected with a reflux condenser and placed on the steam-bath until the separated fat acids form a clear stratum on the upper surface of the liquid4 ,the flask and contents are cooled in ice-water4 ,the fat acids having quite solidified1 the liquid contents of the flask are poured through a dry filter into a liter flask1 taking care not to break the cake4 ,between #bjj and #cjj cubic centimeters of water are brought into the flask1 the cork with the condenser reinserted and the flask placed on the steam-bath until the cake of acid is thoroughly melted4 ,during the melting of the cake of fat acids1 the flask should occasionally be agitated with a rotary motion in such a way that its contents are not made to touch the cork4 ,when the fat acids have again separated into an oily layer1 the flask and its contents are cooled in ice-water and the liquid filtered through the same filter into the same liter flask as before4 ,this treatment with hot water1 followed by cooling and filtration of the wash water1 is repeated three times1 the washings being added to the first filtrate4 ,the mixed washings and filtrate are made up to one liter1 and #ajj cubic centimeters thereof in duplicate are titrated with decinormal sodium hydroxid4 ,the number of cubic centimeters of sodium hydroxid required for each #ajj cubic centimeters of the filtrate is multiplied by ten4 ,the number so obtained represents the volume of decinormal sodium hydroxid neutralized by the soluble fat acids of the fat1 plus that corresponding to the excess of the standard acid used1 viz41 one cubic centimeter4 ,the number is therefore to be diminished by five1 corresponding to the excess of one cubic centimeter of half normal acid4 ,this corrected volume multiplied by #j4jjhh gives the weight of soluble acids as butyric acid in the amount of fat saponified4 ,insoluble ,acids4--,the flask containing the cake of insoluble fat acids from the above determination and the paper through which the soluble fat acids have been filtered are allowed to drain and dry for twelve hours1 when the cake1 together with as much of the fat acids as can be removed from the filter paper1 is transferred to a weighed evaporating dish4 ,the funnel1 with the filter1 is then placed in an erlenmeyer and the paper thoroughly washed with absolute alcohol4 ,the flask is rinsed with the washings from the filter paper1 then with pure alcohol1 and the rinsings transferred to the evaporating dish4 ,the dish is placed on the steam-bath until the alcohol is evaporated1 dried for two hours at #ajj1 cooled in a desiccator and weighed4 ,it is again placed in the air-bath for two hours1 cooled as before and weighed4 ,if there be any considerable decrease in weight1 reheat two hours and weigh again4 ,the final weighing gives the weight of insoluble fat acids in the sample1 from which the percentage is easily calculated4 ,the quantity of non-volatile and insoluble acids in common glycerids is from ninety-five to ninety-seven parts in #ajj4 ,the glycerids yield almost the same proportion of fat acids and glycerol when the acids are insoluble and have high molecular weights4 ,when the acids are soluble and the molecular weight low the proportion of acids decreases and that of glycerol increases4 ,in the following table will be found the data secured by quantitive saponification and separation of soluble and insoluble acids found in the more common glycerids3#cbb ,yield per #ajj parts ,molecular weight of of glycerid4 ,glycerid4 ,fat acid4 ,glycerid4 ,fat acid4 ,fat acid4 ,glycerol4 ,stearin ,stearic #hij #bhd #ie4gc #aj4cd ,olein ,oleic #hhd #bhb #ie4gj #aj4da ,palmitin ,palmitic #hjf #bef #ie4bh #aa4db ,myristin ,myristic #gbb #bbh #id4dg #ab4gd ,laurin ,lauric #fch #bjj #id4ie #ad4db ,caprin ,capric #eid #agb #ic4ad #ae4dh ,caproin ,caproic #chf #aaf #ij4af #bc4hc ,butyrin ,butyric #cjb #hh #hg4da #cj4df ,the general expression for the saponification of a neutral fat is ,c,h,o4,r #c;,h,o #c,r4,,oh ,c,h,o1 in which ,r represents the acid radicle4 ,it is evident from this that the yield of more than #ajj parts of fat acids and glycerol given by glycerids is due to the absorption of water during the reaction4 #ceb4 ,formulas for ,general ,calculations4--,for calculating the theoretical yields of fat acids and glycerol1 the following general formulas may be used3 ,let ,m the molecular weight of the fat acid3 ,k saponification value3 ,f the quantity of free fat acids in the glycerid3 ,n the quantity of neutral fat in the glycerid3 ,a the number of milligrams of potassium hydroxid required to saturate the free acid in one gram of the sample4 ,the free acid is determined by the method given below4 ,m grams of a fat acid require #efajj milligrams of potassium hydroxid for complete neutralization while ,f grams corresponding to #ajj grams of fat are saturated by #ajj ,a milligrams of the alkali4 ,then ,m 3 #efajj ,f 3 #ajj;,a4 ,,am ,whence ,f ------ 7#a74 #efa ,likewise since ,m grams of fat acid require the quantity of potassium hydroxid mentioned above we have3 #a 3 ,k ,m 3 #efajj1 #efajj ,whence ,m ------ 7#b74 ,k ,substituting this value of ,m in 7#a7 we have ,a #efajj #ajj;,a ,f ------------ ------- 7#c74 #efa ,k ,k ,it is evident that it is not necessary to calculate the acid value 7,a7 of the sample and the saponification value 7,k7 of the free fat acids1 the ratio ,a_/,k alone being required4 ,it will be sufficient therefore to substitute for ,a and ,k the number of cubic centimeters of alkali solutions required for one gram of the fat and one gram of the fat acids1 respectively4 ,if a and b represent these numbers the formula may be written #ajj;a ,f ------- 7#d72 b #ajj;a and ,n #ajj - ,f #ajj - ------ 7#e74 b ,to simplify the determinations1 it may be assumed that the free fat acids have the same molecular weight as those still in combination with the glycerol in any given sample4 ,on this assumption1 the process may be carried on by determining the acid value ,a and the saponification value ,k for the total fat acids4 ,the mean molecular weight ,m1 the percentage of free fat acids ,f1 and the proportion of neutral fat ,n1 may then be calculated from the formulas 7#b71 7#c71 7#d71 and 7#e74 ,further1 let ,g the quantity of glycerol and ,l that of fat acids obtainable from one gram of neutral fat1 that is1 _/ of ,h the percentage of total fat acids4 ,the molecular weight of the neutral fat in each case is #c,m #ch4 ,therefore1 #c,m #ch parts of neutral fat yield #c,m parts of fat acids and ninety-two parts of glycerol 7,c,h,o #ib74 ,h #c,m ,then ,l ----- ---------- 7#f72 #ajj #c,m #ch #ib and ,g --------- 7#g74 #c,m #ch ,n per cent of neutral fat yields1 therefore1 on saponification1 the following theoretical quantities of fat acids ,f1 and glycerol ,g expressed as parts per hundred4 #c,m ,f ,n -------- 7#h72 #c,m #ch #ib and ,g ,n --------- 7#i74 #c,m #ch ,formula 7#i7 expresses also the total yield of glycerol from any given sample4 ,for a further discussion of this part of the subject a work of a more technical character may be consulted4#cbc #cec4 ,determination of a ,free ,fat ,acid in a ,fat4--,the principle of the method rests upon the comparative accuracy with which a free fat acid can be titrated with a set alkali solution when phenolphthalien is used as an indicator4 ,among the many methods of manipulation which the analyst has at his command there is probably none more simple and accurate than that depending on the solution of the sample in alcohol1 ether1 chloroform1 or carbon tetrachlorid4 ,any acidity of the solvent is determined by separate titration and the proper correction made4 ,either an aqueous or alcoholic solution of the alkali may be used1 preferably the latter4 ,the alkaline solution may be approximately or exactly decinormal1 but it is easier to make it approximately so and to determine its real value before each operation by titration against a standard decinormal solution of acid4 ,about ten grams of the sample and fifty cubic centimeters of the solvent will be found convenient quantities4 ,example4--,ten grams of rancid olive oil dissolved in alcohol ether require three and eight-tenths cubic centimeters of a solution of alcoholic potash to saturate the free acid present4 ,when titrated with decinormal acid the potash solution is found to contain #be4g milligrams of potassium hydroxid in each cubic centimeter4 ,the specific gravity of the oil is #j4iag and the weight used therefore #i4ag grams4 ,then the total quantity of potassium hydroxid required for the neutralization of the acid is #be4g #c4h #ig4g milligrams4 ,the acid value ,a is therefore3 #c4h #be4g ,a ----------- #aj4f #i4ag ,it is customary to regard free acid as oleic1 molecular weight #bhb4 ,on this assumption the percentage of free acids in the above case is found by the formula #c4h #be4g #bhb ,a 7per cent7 ----------------- #e4ce #efa #i4ag #ced4 ,identification of ,oils and ,fats4--,properly1 the methods of identifying and isolating the different oils and fats should be looked for in works on food adulteration4 ,there are1 however1 many characteristics of these glycerids which can be advantageously discussed in a work of this kind4 ,many cases arise in which the analyst is called upon to determine the nature of a fat and discover whether it be admixed with other glycerids4 ,it is important often to know in a given case whether an oil be of animal or vegetable origin4 ,many of the methods of analysis already described are found useful in such discriminations4 ,for instance1 a large amount of soluble or volatile acids in the sample under examination1 would indicate the presence of a fat derived from milk while the form of the crystals in a solid fat would give a clue to whether it were the product of the ox or the swine4 ,in the succeeding paragraphs will be briefly outlined some of the more important additional methods of determining the nature and origin of fats and oils of which the history is unknown4 ,the data obtained by means of the methods which have been described1 both physical and chemical1 are all useful in judging the character and nature of a glycerid of unknown origin4 ,the colorations produced by oxidizing agents1 in the manner already set forth will be found useful1 especially when joined to those obtained with cottonseed and sesame oils yet to be described4 ,for instance1 the red coloration produced by nitric acid of #a4cg specific gravity is regarded by some authorities as characteristic of cottonseed oil as well as the reduction by it of silver nitrate4 ,the coloration tests with silver nitrate 7paragraph #cbj7 and with phosphomolydic acid 7paragraph #cah7 are also helpful in classifying oils in respect of their animal or vegetable origin4 ,the careful consideration of these tests1 together with a study of the numbers obtained by treating the samples with iodin1 and the heat of bromination and sulfuric saponification1 is commended to all who are interested in classifying oils4 ,in addition to these reactions a few specific tests are added for more detailed work4 #cee4 ,consistence4--,it has already been said that oils are mostly of vegetable origin and the solid fats of animal derivation4 ,in the animal economy it would be a source of disturbance to have in the tissues a large body of fat which would remain in a liquid state at the normal temperature of the body4 ,nearly all the animal fats are found to have a higher melting point than the body containing them4 ,an exception is found in the case of butter fat1 but it should be remembered that this fat is an excretion and not intended for tissue building until it has undergone subsequent digestion4 ,fish oils are another notable exception to the rule1 but in this case these oils can hardly be regarded as true glycerids in the ordinary sense of that term4 ,in general1 it may be said that a sample of a glycerid1 which in its natural state remains liquid at usual room temperatures1 is probably an oil of vegetable origin4 ,fish oils have also an odor and taste which prevent them from being confounded with vegetable oils4 ,in oils which are manufactured from animal glycerids such as lard oil1 the discrimination is more difficult but peculiarities of taste and color are generally perceptible4 #cef4 ,nature of the ,fat ,acid4--,when it is not possible to discriminate between samples by the sensible physical properties just described1 much light can be thrown on their origin by the determination of their other physical properties1 such as specific gravity1 refractive index1 melting point1 etc41 in the manner already fully described4 ,further light may be furnished by saponification and separation of the fat acids4 ,the relative quantities of oleic1 stearic1 palmitic1 and other acids will help to a correct judgment in respect of the nature of the sample4 ,the vegetable oils and lard oils1 for instance1 consist chiefly of olein2 lard and tallow contain a large proportion of stearin2 palm oil and butter fat contain considerable portions of palmitin1 and the latter is distinguished moreover by the presence of soluble and volatile acids combined as butyrin and its associated glycerids4 ,oleic acid can be rather readily separated from stearic and palmitic by reason of the solubility of its lead salts in ether4 ,one method of accomplishing this separation has already been described 7paragraph #cci74 #ceg4 ,separation with ,lime4--,a quicker1 though perhaps not as accurate a separation of the oleic from the palmitic and stearic acids1 is accomplished by means of lime according to the method developed by ,bondzyuski and ,rufi4#cbd ,this process is used chiefly1 however1 to separate the free fat acids 7palmitic1 stearic7 from the neutral fat and the free oleic acid4 ,it probably has no point of superiority over the lead process4 #ceh4 ,separation of the ,glycerids4--,the fact that olein is liquid at temperatures allowing palmitin and stearin to remain solid1 permits of a rough separation of these two classes of bodies by mechanical means4 ,the mixed fats are first melted and allowed to cool very slowly4 ,in these conditions the stearin and palmitin separate from the olein in a crystalline form and the olein is removed by pressure through bags4 ,in this way lard is separated into lard oil1 consisting chiefly of olein1 and lard stearin1 consisting largely of stearin4 ,beef 7caul7 fat is in a similar manner separated into a liquid 7oleo-oil7 and a solid 7oleo-stearin7 portion4 ,it is evident that these separations are only approximate1 but by repeated fractionations a moderately pure olein or stearin may be obtained4 #cei4 ,separation as ,lead ,salts4--,muter's process1 with a special piece of apparatus1 has already been described 7#cci74 ,for general analytical work the special tube may be omitted4 ,in a mixture of insoluble free fat acids all are precipitated by lead acetate1 and the resulting soap may be extracted with ether1 either with successive shakings or in a continuous extraction apparatus4 ,in this latter case a little of the lead stearate or palmitate may pass into solution in the hot ether and afterwards separate on cooling4 ,when the operation is conducted on from two to three grams of the dry mixed acids1 the percentage proportions of the soluble and insoluble acids 7in ether7 can be determined4 ,the lead salt which passes into solution can be decomposed and the oleic acid removed1 dried and weighed4 ,dilute hydrochloric acid is a suitable reagent for decomposing the lead soap4 ,the difference between the weight of the oleic acid and that of the mixed acids before conversion into lead soap furnishes the basis for the calculation4 ,for further details in respect of the fat acids the reader may consult special analytical works4#cbe #cfj4 ,separation of ,arachidic ,acid4--,peanut oil is easily distinguished from other vegetable glycerids by the presence of arachidic acid4 ,the method used in this laboratory for separating arachidic acid is a modification of the usual methods based on the process as carried out by ,milliau4#cbf ,about twenty grams of the oil are saponified with alcoholic soda1 using twenty cubic centimeters of #cf baum soda solution diluted with #ajj cubic centimeters of ninety per cent alcohol4 ,when the saponification is complete1 the soda is converted into the lead soap by treatment with a slight excess of a saturated alcoholic solution of lead acetate4 ,good results are also obtained by using dilute alcohol1 viz41 fifty per cent1 instead of ninety per cent1 in preparing the lead acetate solution4 ,while still warm the supernatant liquid is decanted1 the precipitate washed by decantation with warm ninety per cent alcohol and triturated with ether in a mortar four times1 decanting the ethereal solution in each instance4 ,by this treatment all of the lead oleate and hypogaeate are removed and are found in the ethereal solution1 from which they can be recovered and the acids set free by hydrochloric acid and determined in the usual way4 ,the residue is transferred to a large dish containing two or three liters of pure water and decomposed by the addition of about fifty cubic centimeters of strong hydrochloric acid4 ,the lead chlorid formed is soluble in the large quantity of water present1 which should be warm enough to keep the free acids in a liquid state in which form they float as a clear oily liquid on the surface4 ,the free acids are decanted and washed with warm water to remove the last traces of lead chlorid and hydrochloric acid4 ,the last traces of water are removed by drying in a thin layer in vacuo4 ,practically all of the acids1 originally present in the sample except oleic and hypogaeic1 are thus obtained in a free state and their weight is determined4 ,the arachidic acid may be separated almost quantitively by dissolving the mixed acids in forty cubic centimeters of ninety per cent alcohol1 adding a drop of hydrochloric acid1 cooling to #af and allowing to stand until the arachidic acid has crystallized4 ,the crystals are purified by washing twice with twenty cubic centimeters of ninety per cent and three times with the same quantity of seventy per cent alcohol4 ,the residual impure arachidic acid is dissolved in boiling absolute alcohol1 poured through a filter and washed with pure hot alcohol4 ,the filtrate is evaporated to dryness and heated to #ajj until a constant weight is obtained4 ,from the above data1 the percentages of oleic1 hypogaeic1 arachidic and other acids in the sample examined are calculated4 ,in the above process1 owing to the pasty state of the lead soaps1 the trituration in a mortar with ether is found troublesome4 ,the extraction of the lead oleate and hypogaeate is facilitated by throwing the pasty ethereal mass on a filter and washing it thoroughly with successive portions of about fifty cubic centimeters of ether4 ,by this variation1 it was found by ,krug in this laboratory1 that less ether was required and a more complete removal of the lead oleate effected4 ,the solution of the lead oleate is completed by about half a dozen washings with ether as above described4 ,the extraction may also be secured by placing the lead soaps in a large extracting apparatus and proceeding as directed in paragraph #dj4 ,the residue is washed from the filter paper into a large porcelain dish and decomposed as already described with hydrochloric acid4 ,after the separation is complete1 the mixture is cooled until the acids are solid4 ,the solid acids are then transferred to a smaller dish1 freed of water and dissolved in ether4 ,the ethereal solution is washed with water to remove any traces of lead salt or of hydrochloric acid4 ,after the removal of the ether1 the arachidic acid is separated as has already been described4 ,the melting point of pure arachidic acid varies from #gc to #ge4 #cfa4 ,detection of ,arachis 7,peanut7 ,oil4--,kreis has modified the usual process of ,renard for the detection of arachis oil1 by precipitating the solution of the fat acid with an alcoholic instead of an aqueous solution of lead acetate1 in a manner quite similar to that described above4#cbg ,the fat acids are obtained in the usual manner1 washed with hot water and the acids from twenty grams of the oil dissolved in #ajj cubic centimeters of ninety per cent alcohol4 ,the solution is cooled in ice-water and the fat acids precipitated by the addition of fifteen grams of lead acetate dissolved in #aej cubic centimeters of ninety per cent alcohol4 ,the precipitate1 after standing for two hours1 is separated by filtration through cotton wool and is extracted for six hours with ether4 ,the residue is boiled with #bej cubic centimeters of five per cent hydrochloric acid until the fat acids appear as a clear oily layer upon the surface4 ,the acids thus obtained are washed with hot water to remove lead chlorid1 dried by pressing between blotting paper1 dissolved in #ajj cubic centimeters of ninety per cent alcohol1 cooled to #ae and allowed to stand for several hours1 after which time any arachidic acid present is separated by crystallization and identified in the usual manner4 ,when it is not important to obtain all of the acid present1 the process may be simplified in the following manner3 ,the fat acids obtained from twenty grams of oil are dissolved in #cjj cubic centimeters of ether and treated at the temperature of ice-water with a quantity of the alcoholic lead acetate solution mentioned above4 ,lead oleate remains in solution and the precipitate which forms after a few hours consists almost wholly of the lead salts of the solid fat acids4 ,the precipitate is collected1 washed with ether and identified in the usual manner4 #cfb4 ,cottonseed ,oil1 ,bechi's ,test4--,crude1 fresh cottonseed oil1 when not too highly colored1 and generally the refined article1 may be distinguished from other oils by the property of reducing silver salts in certain conditions4 ,the reaction was first noticed by ,bechi and has been the subject of extensive discussions4#cbh ,the process as proposed by ,bechi has been modified in many ways but apparently without improving it4 ,it is conducted as follows3 ,one gram of silver nitrate is dissolved in #bjj cubic centimeters of ninety-eight per cent alcohol and forty cubic centimeters of ether and one drop of nitric acid added to the mixture4 ,ten cubic centimeters of the oil are shaken in a test tube with one cubic centimeter of this reagent1 and then with ten cubic centimeters of a mixture containing #ajj cubic centimeters of amyl alcohol and ten of colza oil4 ,the mixture is divided into two portions1 one of which is put aside for future comparison and the other plunged into boiling water for fifteen minutes4 ,a deep brown or black color1 due to the reduction of silver1 reveals the presence of cottonseed oil4 ,in this laboratory the heating is accomplished in a small porcelain dish on which is often deposited a brilliant mirror of metallic silver4 ,the white color of the porcelain also serves as a background for the observation of the coloration produced4 ,in most instances a green color has been noticed after the reduction of the silver is practically complete4 ,unless cottonseed oil has been boiled or refined in some unusual way1 the test1 as applied above1 is rarely negative4 ,the reduction of the silver is doubtless due to some aldehydic principle1 present in extremely minute quantities1 and which may be removed by some methods of technical treatment4 ,the silver nitrate test therefore is reliable when the reduction takes place1 but the absence of a distinct reaction may not in all cases prove the absence of cottonseed oil4 #cfc4 ,milliau's ,process4--,milliau has proposed the application of the silver salt directly to the free fat acids of the oil instead of to the oil itself4#cbi ,about fifteen cubic centimeters of the oil are saponified with alcoholic potash in the usual manner1 #aej cubic centimeters of water added to the dish and the mixture boiled until the alcohol is evaporated4 ,the fat acids are freed by the addition of decinormal sulfuric acid and as they rise to the surface in a pasty condition are removed with a spoon4 ,the free acids are washed with distilled water4 ,the water is drained off and the free acids dissolved in fifteen cubic centimeters of ninety-two per cent alcohol and two cubic centimeters of a three per cent solution of silver nitrate4 ,the test tube containing the mixture is well shaken and placed in a water-bath1 out of contact with light1 and left until about one-third of the alcohol is evaporated4 ,ten cubic centimeters of water are added1 the heating continued for a few minutes and the color of the supernatant fat acids observed4 ,the presence of cottonseed oil is revealed by the production of a lustrous precipitate which colors the fat acids black4 ,in some cases the process of ,milliau gives better results than the original method of ,bechi1 but this is not always the case4 ,it does away with the use of amyl alcohol and colza oil1 but its manipulation is more difficult4 ,in all doubtful cases the analyst should apply both methods4 #cfd4 ,detection of ,sesame ,oil4--,milliau has pointed out a characteristic reaction of this oil which may be used with advantage in cases of doubtful identity4#ccj ,the identification is based on the fact that the free acids of sesame oil1 or some concomitant thereof1 give a rose-red color when brought in contact with a solution of sugar in hydrochloric acid4 ,the analytical process is conducted as follows3 ,about fifteen grams of the oil are saponified with alcoholic soda and when the reaction is complete treated with #bjj cubic centimeters of hot water and boiled until the alcohol is removed4 ,the fat acids are set free with decinormal sulfuric acid and removed with a spoon as they rise to the surface in a pasty state1 in which condition they are washed by shaking with water in a large test tube4 ,when washed1 the acids are placed in an oven at #aje until the greater part of the water is evaporated and the acids begin to become fluid4 ,at this point they are treated with half their volume of hydrochloric acid saturated with finely ground sugar4 ,on shaking the mixture1 a rose color is developed which is characteristic of the sesame oil4 ,other oils give either no coloration or at most a yellow tint4 #cfe4 ,the ,sulfur ,chlorid ,reaction4--,some vegetable oils1 when treated with sulfur chlorid1 give a hard product similar to elaidin1 while lard does not4 ,this reaction is therefore helpful in discriminating between some vegetable and animal glycerids4 ,the process which is described by ,warren has been used with some satisfaction in this laboratory4#cca ,five grams of the oil or fat are placed in a tared porcelain dish and treated with two cubic centimeters of carbon bisulfid and the same quantity of sulfur chlorid4 ,the dish is placed on a steam-bath and its contents stirred until the reaction is well under way4 ,the heating is continued until all volatile products are evaporated1 the hard mass being well rubbed up to facilitate the escape of imprisoned vapors4 ,the powdered or pasty mass is transferred to a filter and washed with carbon bisulfid to remove all unaltered oil4 ,the washing with carbon bisulfid is hastened by pressure and about #bjj cubic centimeters of the solvent should be used4 ,after drying1 the weight of insoluble matter is obtained and deducted from the total weight of the sample used4 ,the color and tenacity of the hard1 insoluble portion are characteristic4 ,the quantitive part of the operation appears to have but little value1 but applied qualitively in this laboratory it produces hard1 leathery masses with cotton1 olive and peanut oils1 and but little change in lard and beef fats4 ,qualitively applied1 the process is conducted as described above but without making the weighings4 ,in this instance it is as easy of application as the process of ,bechi and is deserving of greater attention than has been given it by analysts4 ,in the combination which takes place between the sulfur and the fat it is probable that only addition products are formed1 since the quantity of alkali required for saponification is not diminished by previously treating the fat with sulfur chlorid4#ccb ,the reactions which take place are probably well represented by the following equations1 in which oleic acid is treated with sulfur chlorid3 ,c,h,o ,s ,c,h,s4,o4 ,c,h,s4,o ,na,o,h ,c,h,,so,na ,h,o4 #cff4 ,detection of ,cholesterin and ,phytosterin in ,glycerids4--,cholesterin is often found in animal glycerids and a corresponding body1 phytosterin1 is sometimes found in oils of a vegetable origin4#ccc ,when one of these two bodies is present it may be useful in distinguishing between animal and vegetable glycerids4 ,they are detected as follows3 ,fifty grams of the glycerids in each case are saponified with alcoholic alkali1 preferably potash1 in order to have a soft soap4 ,after saponification is complete1 the alcohol is evaporated and the residual soap dissolved in two liters of water4 ,the mixture is shaken with ether and the ethereal solution evaporated to a small bulk4 ,the residue1 which may contain a small quantity of unsaponified fat1 is again treated with alcoholic potash and subjected a second time to the action of ether1 as indicated above1 with the addition of a few drops of water and of alcohol if the emulsion separate slowly4 ,the ethereal extract finally secured is allowed to evaporate slowly and the cholesterin 7phytosterin7 is obtained in a crystalline form4 ,the melting point of the cholesterin crystals is #adf and that of the phytosterin #acb4 ,cholesterin crystallizes in thin rhombic tables while phytosterin separates in stellar aggregates or in bundles of long needles4 ,when dissolved in chloroform the two products show different color reactions with sulfuric acid1 cholesterin giving a cherry and phytosterin a blue-red tint4 ,in a mixture of animal and vegetable glycerids the two products are obtained together and the melting point of the mixture may afford some idea of the relative quantities of each present4 ,it is evident1 however1 that no reliable judgment can be formed from these data of the relative proportions of the two kinds of glycerids in the original sample4 #cfg4 ,cholesterin and ,paraffin in ,ether ,extracts4--,in ethereal extracts of some bodies1 especially of flowers of the chrysanthemum1 paraffin is found combined with cholesterin4 ,the two bodies may be separated as follows3#ccd ,the ether extract is treated with aqueous then with alcoholic potash several times2 the residue soluble in ether is a solid body melting at from #gj to #ajj4 ,if the ethereal solution be cooled in a mixture of snow and salt1 a crystalline deposit is formed4 ,this substance1 purified by repeated precipitations1 is obtained colorless in fine crystalline scales melting at #fd4 ,it is very soluble in ether1 benzene and chloroform1 almost insoluble in cold alcohol1 and somewhat soluble in hot4 ,its percentage composition is3 ,per cent4 ,carbon #he4jj ,hydrogen #ad4ie ,it is therefore a paraffin4 ,the ethereal solution1 freed by the above process from paraffin1 leaves on evaporation a crystalline mass which is cholesterin1 retaining still a small quantity of fat matters4 ,in treating the crystals with alcoholic potash these fat bodies are saponified and the residue is taken up with ether4 ,the cholesterin is obtained in fine needles melting at from #agj to #agf4 ,it presents all the reactions of cholesterin1 especially the characteristic reaction with chloroform and sulfuric acid4 #cfh4 ,absorption of ,oxygen4--,among oils a distinction is made between those which oxidize readily and those which are of a more stable composition4 ,linseed oil1 for instance1 in presence of certain metallic oxids1 absorbs oxygen readily and is a type of the drying oils1 while olive oil represents the opposite type4 ,the method of determining the quantity of oxygen absorbed is due to ,livache and is carried out as follows3#cce ,precipitated metallic lead 7by zinc7 is mixed in a flat dish1 with the oil to be tested1 in the proportions of one gram of lead to three-quarters of a gram of oil1 and exposed to the air and light of the workroom4 ,the dish is weighed from time to time until there is no longer any increase in weight4 ,instead of lead1 finely divided copper has been used by ,krug in this laboratory1 but the percentage of absorption of oxygen is not so high with copper as with lead4 ,krug found the quantities of oxygen absorbed1 after nine days1 by the samples treated with copper and lead respectively to be the following3 ,copper1 per cent ,lead1 per oxygen absorbed4 cent oxygen absorbed4 ,olive oil #a4fi #b4jc ,cottonseed oil #d4be #e4cj ,peanut oil #b4gd #c4hg ,linseed oil #e4ee #g4cb ,livache found that linseed oil absorbed about twice as much oxygen as indicated by the data just given4 #cfi4 ,elaidin ,reactions4--,in discriminating between oils and fats having a preponderance of olein and others with a smaller proportion of that glycerid1 the conversion of the olein into its isomer elaidin is of diagnostic value4 ,the following will be found a convenient method of applying this test3#ccf ,about ten cubic centimeters of the oil are placed in a test tube together with half that quantity of nitric acid and one gram of mercury4 ,the mixture is shaken until the mercury dissolves when the mass is allowed to remain at rest for twenty minutes4 ,at the end of this time it is again shaken and placed aside4 ,in from one to three hours the reaction is complete4 ,olive1 peanut and lard oils give very hard elaidins4 ,the depth to which a plunger of given weight and dimensions sinks into an elaidin mixture at a given temperature1 has been used as a measure of the percentage of olein contained in the sample of oil1 but it is evident that such a determination is only roughly approximate4 ,copper may be used instead of mercury for the generation of the oxids of nitrogen1 but it is not so effective4 ,the vapors of nitric oxids may also be conducted directly into the oil from a convenient generator4 ,the reaction may also be accomplished by shaking the oil with nitric acid and adding1 a drop at a time1 a solution of potassium nitrite4 ,,authorities ,,cited ,,in ,,part ,,fourth4 #bbi ,benedikt and ,lewkowitsch2 ,oils1 ,fats1 ,waxes1 p4 #a4 #bcj ,op4 cit4 supra1 p4 #df4 #bca ,archiv fr ,physiologie1 #ahie1 ,band #fa1 ,s4 #cda3 ,chemiker-,zeitung ,repertorium1 ,band #af1 ,s4 #cch4 #bcb ,vid4 op4 cit4 #a1 p4 #fc4 #bcc ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #be4 #bcd ,journal of the ,society of ,chemical ,industry1 #ahhf1 p4 #ejh4 #bce ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #dbc4 #bcf ,vid4 op4 cit4 supra1 p4 #dce4 #bcg ,vid4 op4 cit4 supra1 p4 #dcg4 #bch ,vid4 op4 et loc4 cit4 supra4 #bci ,benedikt and ,lewkowitsch2 ,oils1 ,fats1 and ,waxes1 pp4 #if et seq43 ,zune2 ,analyse des ,beurres1 pp4 #bf et seq4 #bdj ,journal of the ,society of ,chemical ,industry1 #ahhe1 p4 #ece4 #bda ,vid4 op4 cit4 #a1 p4 #ig4 #bdb ,vid4 op4 cit4 #g1 p4 #ddc4 #bdc ,vid4 op4 cit4 #a1 pp4 #ig and #ih4 #bdd ,butter1 its ,analysis and ,adulterations1 p4 #bd4 #bde ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cd4 #bdf ,vid4 op4 cit4 #g1 p4 #ddg4 #bdg ,analyse des ,beurres1 pp4 #cc et #fc3 ,zeitschrift fr ,instrumentenkunde1 #ahhg1 ,ss4 #af1 #ee1 #cib1 #ddd3 ,zeitschrift fr physikalische ,chemie1 ,band #ah1 ,s4 #bid4 7,ou4 pp4 #cbh-i and #ccd read ,amagat for ,armagat47 #bdh ,zeitschrift fr physikalische ,chemie1 ,band #ah1 ,s4 #bid4 #bdi ,american ,chemical ,journal1 ,vol4 #aj1 p4 #cib4 #bej ,vid4 op4 cit4 #g1 pp4 #dgc et seq4 #bea ,jean2 ,chimie ,analytique des ,matires ,grasses1 p4 #bf4 #beb ,vid4 op4 cit4 supra1 p4 #ca4 #bec ,the ,analyst1 ,vol4 #bj1 p4 #ace4 #bed ,schlussbericht ber die ,butteruntersuchungsfrage1 ,milchwirthschaftlicher ,verein1 ,korrespondenzblatt1 ,no4 #ci1 #ahia1 ,s4 #ae4 #bee ,vid4 op4 cit4 #g1 p4 #ge4 #bef ,journal of the ,american ,chemical ,society1 ,vol4 #ae1 p4 #agc4 #beg ,communicated by ,krug to author4 #beh ,vid4 op4 cit4 #g1 pp4 #ddi et seq4 #bei ,vid4 op4 cit4 #bh1 ,vol4 #ah1 p4 #ahi4 #bfj ,vid4 op4 cit4 #g1 ,plates #cb and #ce4 #bfa ,vid4 op4 cit4 supra1 p4 #deb4 #bfb ,vid4 op4 cit4 supra41 p4 #ic4 #bfc ,vogel2 ,practische ,spectralanalyse1 ,s4 #bgi3 ,zune2 ,analyse des ,beurres1 ,tome #b1 p4 #dh3 ,benedikt and ,lewkowitsch2 ,oils1 ,fats1 ,waxes1 p4 #hc4 #bfd ,bulletin de l',association ,belge des ,chimistes1 ,tome #i1 p4 #ade4 #bfe ,journal of the ,chemical ,society1 ,abstracts1 ,vol4 #df1 p4 #ajgh3 ,dingler's ,polytechnisches ,journal1 ,band #beb1 ,s4 #bif4 #bff ,the ,analyst1 ,july #ahid1 p4 #aeb4 #bfg ,rapport sur les ,procd pour reconnitre les ,falsifications des ,huiles d',olive1 p4 #cg4 #bfh ,vid4 op4 cit4 #g1 p4 #bea4 #bfi ,taylor2 ,annual ,report ,u4 ,s4 ,department of ,agriculture1 #ahgg1 p4 #fbb3 ,milliau2 ,journal of the ,american ,chemical ,society1 ,vol4 #ae1 p4 #aec4 #bgj ,gantter2 ,zeitschrift fr analytische ,chemie1 #ahic1 ,band #cb1 ,s4 #cjc4 #bga ,welmans2 ,journal of the ,society of ,chemical ,industry1 #ahib1 p4 #edh4 #bgb ,vid4 op4 cit4 #a1 p4 #bed4 #bgc ,pharmaceutische ,zeitung1 #ahia1 p4 #gih3 ,the ,analyst1 ,vol4 #ag1 p4 #ei4 #bgd ,comptes rendus1 ,tome #aab1 p4 #aje4 #bge ,pearmain and ,moor2 ,the ,analyst1 ,vol4 #bj1 p4 #agd4 #bgf ,pharmaceutische ,zeitschrift fr ,russland1 #ahhh1 ,s4 #gba3 ,american ,journal of ,pharmacy1 #ahhi1 p4 #bc4 #bgg ,vid4 op4 cit4 #g1 p4 #ejb4 #bgh ,muir2 ,elements of ,thermal ,chemistry1 p4 #be et seq4 #bgi ,comptes rendus1 ,tome #ce 7#aheb71 p4 #egb4 #bhj ,allen2 ,commercial ,organic ,analysis1 ,vol4 #b1 p4 #ef4 #bha ,vid4 op4 cit4 #a1 p4 #bce2 et op4 cit4 #bc1 p4 #bag4 #bhb ,vid4 op4 cit4 #g1 p4 #dd4 #bhc ,vid4 op4 cit4 supra1 p4 #dde3 ,proceedings ,american ,public ,health ,association1 ,vol4 #aj4 #bhd ,vid4 op4 cit4 #bc1 p4 #fa4 #bhe ,journal of the ,society of ,chemical ,industry1 #ahia1 p4 #bcd4 #bhf ,vid4 op4 cit4 #a1 p4 #bdj4 #bhg ,the ,analyst1 ,vol4 #bb1 p4 #eh4 #bhh ,vid4 op4 cit4 supra1 ,vol4 #bj1 p4 #adf4 #bhi ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #cgh4 #bij ,dingler's ,polytechnisches ,journal1 #ahhd1 ,ss4 #bec-bha3 ,journal of the ,society of ,chemical ,industry1 #ahhd1 p4 #fda4 #bia ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cb4 #bib ,liebermann2 ,berichte der deutschen chemischen ,gessellschaft1 ,band #bd1 ,s4 #daag4 #bic ,vid4 op4 cit4 #a1 p4 #acf4 #bid ,vid4 op4 cit4 #eg1 #ahie1 pp4 #acj and #ajcj4 #bie ,zeitschrift fr analytische ,chemie1 ,band #cb1 ,ss4 #aha et seq4 #bif ,vid4 op4 cit4 #fa1 ,vol4 #af1 p4 #cgb4 #big ,zeitschrift fr angewandte ,chemie1 #ahie1 ,s4 #bed4 #bih ,chemiker-,zeitung1 ,band #ai1 ,ss4 #aghf and #ahca4 #bii ,vid4 op4 cit4 #fa1 ,vol4 #af1 p4 #bgg4 #cjj ,pharmaceutical ,journal1 ,sept4 #be1 #ahhj4 #cja ,vid4 op4 cit4 #ei1 ,vol4 #bj1 p4 #ej4 #cjb ,williams2 vid4 op4 cit4 supra1 ,vol4 #bj1 p4 #bgg4 #cjc ,vid4 op4 cit4 #ei1 #ahhi1 p4 #fa4 #cjd ,vid4 op4 cit4 #fa1 ,vol4 #ae1 p4 #aaj4 #cje ,zeitschrift fr physiologische ,chemie1 ,band #ad1 ,s4 #eii2 ,band #ab1 ,s4 #cba2 ,band #af1 ,s4 #aeb4 #cjf ,vid4 op4 cit4 #a1 p4 #fj4 #cjg ,vid4 op4 cit4 supra1 p4 #eeg4 #cjh ,vid4 op4 cit4 #g1 p4 #dei2 vid4 op4 cit4 #fc1 p4 #bg4 #cji ,vid4 op4 cit4 #fi1 #ahie1 ,s4 #gba4 #caj ,vid4 op4 cit4 #fg1 ,band #ah1 ,s4 #aii3 vid4 op4 cit4 #g1 pp4 #eh-dfa3 vid4 op4 cit4 #fc1 p4 #cj4 #caa ,vid4 op4 cit4 #eb1 p4 #dj4 #cab ,vid4 op4 cit4 #a1 p4 #aai4 #cac ,vid4 op4 cit4 supra1 p4 #abg4 #cad ,monatshefte fr ,chemie und verwandte ,theile anderer ,wissenschaften1 ,band #h1 ,s4 #dj4 #cae ,vid4 op4 cit4 #eg1 #ahij1 p4 #hdf4 #caf ,reichert2 vid4 op4 cit4 #fg1 ,band #ah1 ,s4 #fh4 #cag ,meissl2 vid4 op4 cit4 #fb1 ,band #bcc1 ,s4 #bbi4 #cah ,vid4 op4 cit4 #a1 p4 #aba4 #cai ,vid4 op4 cit4 #fc1 p4 #bh4 #cbj ,vid4 op4 cit4 #fg1 ,band #af1 ,s4 #ade2 ,band #ah1 ,s4 #fh3 vid4 op4 cit4 #g1 p4 #ec3 vid4 op4 cit4 #ei1 #ahgg1 p4 #adg4 #cba ,vid4 op4 cit4 #eg1 #ahhh1 pp4 #ebf and #fig3 ,american ,chemical ,journal1 ,vol4 #aj1 p4 #cbf3 vid4 op4 cit4 #a1 pp4 #abc-abg4 #cbb ,vid4 op4 cit4 #a1 p4 #adc4 #cbc ,vid4 op4 ch4 #g1 p4 #adc4 #cbd ,vid4 op4 cit4 #fg1 #ahij1 ,s4 #d4 #cbe ,allen2 ,commercial ,organic ,analysis1 ,vol4 #b1 pp4 #bbd-bcf4 #cbf ,analyse ,chimique des ,matires ,grasses1 p4 #ac4 #cbg ,chemiker-,zeitung1 ,band #ai1 ,s4 #dea4 #cbh ,annali del ,laboratorio ,chimico1 #ahia-ib1 p4 #aig3 ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #dfe3 ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #a1 p4 #ddi2 ,vol4 #b1 pp4 #aai and #bge2 vid4 op4 cit4 #caa4 #cbi ,rapport present a l',academie ,sciences le #bj fevrier1 #ahhc3 ,analyse des ,matires ,grasses1 p4 #ag3 ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #ddf4 #ccj ,analyse des ,matires ,grasses1 p4 #ae4 #cca ,chemical ,news1 #ahhh1 p4 #aac3 ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #dfh4 #ccb ,vid4 op4 cit4 #fi1 #ahie1 ,s4 #ece4 #ccc ,justus ,liebig's ,annalen der ,chemie1 ,band #aib1 ,s4 #agh3 vid4 op4 cit4 #fg1 ,band #bf1 ,s4 #ege3 vid4 op4 cit4 #g1 p4 #ead4 #ccd ,journal de ,pharmacie et de ,chimie1 #ahhi1 p4 #ddg4 #cce ,moniteur ,scientifique1 ,tome #ac1 p4 #bfc3 vid4 op4 cit4 #fi1 #ahhd1 ,s4 #bfb4 #ccf ,vid4 op4 cit4 #g1 p4 #eae4 ,,part ,,fifth4 ,,separation ,,and ,,estimation ,,of ,,bodies ,,containing ,,nitrogen4 #cgj4 ,nature of ,nitrogenous ,bodies4--,the nitrogenous bodies1 valuable as foods1 belong to the general class of proteids and albuminoids4 ,they are composed chiefly of carbon1 hydrogen1 oxygen1 sulfur and nitrogen4 ,some of them1 as lecithin and nuclein1 contain phosphorus instead of sulfur1 but these resemble the fats rather than the proteids4 ,nitrogenous organic bodies of the class mentioned above are designated by the general name proteids4 ,the term albumin is restricted in a physiological sense to a certain class of proteids4 ,the term albuminoid is often used synonymously1 as above1 for proteids1 but1 more strictly speaking1 it should be reserved for that class of bodies such as gelatin1 mucin1 keratin and the like1 not really proteids1 but1 nevertheless1 closely resembling them4#ccg ,in chemical composition the proteids are characterized by the relative constancy of their nitrogen content1 the mean percentage of this element being about sixteen1 but varying in some instances more than two units from that number4 #cga4 ,classification of ,proteids4--,many classifications of the proteids have been given based on physical1 chemical and physiological characteristics4 ,in respect of origin1 they are divided into two great classes1 viz41 vegetable and animal4 ,in respect of their physical and chemical properties the following classification of the proteids may be made4#cch ,albumins4--,these are proteids soluble in water and not precipitated from their aqueous solutions by sodium chlorid or magnesium sulfate4 ,they are easily coagulated by heat and are represented by three great classes1 viz41 egg-1 serum-1 and lactalbumin4 ,egg albumin occurs in the white of egg2 serum albumin is found in the serum of the blood4 ,vegetable albumins have been prepared from wheat1 rye1 potatoes1 and papaws4 7,carica ,papaya74 ,these vegetable albumins are coagulated by heat at about #gj and are not precipitated by the salt solutions named above1 nor by acetic acid4 ,the myrosin of mustard seeds also resembles vegetable albumin4 ,globulins4--,these bodies are insoluble in water1 soluble in dilute solutions of neutral salts1 but precipitated therefrom by saturation with sodium chlorid or magnesium sulfate4 ,they are coagulated by heat4 ,among others belonging to this group are serum globulin1 fibrinogen1 myosin1 crystalin1 and globin4 ,serum globulin is found in the serum of blood2 cell globulin is found in lymph cells2 fibrinogen occurs in the blood plasma2 plasmin1 in blood plasma2 myosin1 in dead muscles2 vitellin1 in the yolk of eggs2 crystalin1 in the lens of the eye2 haemoglobin1 in the red pigment of the blood2 haemocyanin1 in the blood of certain low grade animals4 ,vegetable globulins are found in the cereals1 leguminous plants1 papaws and other vegetables1 and are divided into two groups1 myosins and paraglobulins4 ,the vegetable myosins coagulate at from #ee to #fj and are precipitated from a saline solution by removing the salt by dialysis4 ,in this form1 however1 they lose their true nature as globulins1 becoming insoluble in weak saline solutions4 ,the vegetable paraglobulins are coagulated at from #gj to #ge4 ,vegetable vitellin1 which is not included in this classification1 can be obtained in a crystalline form and of remarkable purity4#cci ,albuminates4--,this name is given to the compounds of the proteids with metallic oxids or bases1 and also to acid and alkali albumins4 ,they are insoluble in water or dilute neutral salts1 but easily soluble in strong acids or alkalies4 ,casein is a type of this group4 ,acid albumin is made from egg albumin by treatment with hydrochloric acid2 alkali albumin is formed in egg albumin by the action of a dilute alkali2 trinitroalbumin is formed from dry albumin by treatment with nitric acid2 casein or caseinogen is the chief proteid in milk4 ,the chief vegetable albuminates are legumin and conglutin4 ,legumin is a vegetable casein and occurs chiefly in peas1 beans and other leguminous seeds4 ,it is prepared by extracting the meal of the seeds mentioned with dilute alkali1 filtering the extract1 precipitating with acetic acid1 washing the precipitate with alcohol1 and drying over sulfuric acid4 ,treated with sulfuric acid it yields leucin1 tyrosin and glutamic and aspartic acids4 ,conglutin is prepared in a similar manner from almonds4 ,it is probable that these bodies do not exist as such in the fresh seeds in question but are produced therein from the other proteids by the alkali used in extraction4 ,a further description of vegetable proteids will be found in the special paragraphs devoted to the study of these bodies in the principal cereals4 ,proteoses4--,this name is applied to proteids which are not coagulated by heat1 but most of them are precipitated by saturated solutions of neutral salts4 ,they are also precipitated by nitric acid4 ,they are formed from other proteids by the action of proteolytic ferments4 ,the albumoses represent this group4 ,protoalbumose is soluble in distilled water and weak saline solutions and is precipitated by mercuric chlorid and copper sulfate4 ,heteroalbumose is insoluble in distilled water1 but soluble in weak saline solutions1 from which it separates when the salts are removed by dialysis4 ,deuteroalbumose is soluble in distilled water and saline solutions and is not precipitated on saturation with sodium chlorid4 ,it is thrown out by mercuric chlorid but not by copper sulfate4 ,vegetable proteoses are known as phytalbumoses1 two of which have been found in the juice of the papaw mentioned above4 ,they have also been found in cereals4 ,peptones4--,these bodies are very soluble in water but are not thrown out by heat1 by saturation with neutral salts1 nor by nitric acid4 ,they are completely precipitated by tannin and by strong alcohol4 ,the peptones are the only soluble proteids which are not precipitated by saturation with ammonium sulfate4 ,the principal animal varieties are hemi- and anti-peptones4 ,these forms of proteids do not appear to exist as such in vegetable products but are produced in large quantities by treating other proteids with pepsin or pancreatin4 ,in sprouting plants1 there appears to be a widely diffused ferment capable of converting the proteids of the cotyledons into peptonoid bodies and thus fitting them for entering the tissues of the new plant4 ,insoluble ,proteids4--,this class includes a miscellaneous collection of nitrogenous bodies not belonging to any of the definite groups already mentioned4 ,fibrin and gluten are types of these insoluble bodies4 ,fibrin is formed from the fibrinogen of fresh blood and causes coagulation4 ,when washed free of red blood corpuscles it is a white elastic solid4 ,it is insoluble in water and is converted into albumoses and peptones by trypsin and pepsin4 ,it swells up when treated with a very weak one-tenth per cent solution of hydrochloric acid and dissolves to acid albumin when heated therewith4 ,gluten is the most important of the insoluble vegetable proteids and forms the chief part of the nitrogenous constituents of wheat4 ,it is readily prepared by washing wheat flour in cold water1 as will be described further on4 ,it is probably a composite body formed by the process of extraction from at least two proteid bodies existing in wheat4 ,when dried it forms a horny elastic mass of a yellow-gray color4 ,gluten is composed of two bodies1 one soluble the other insoluble in alcohol4 ,the part insoluble in alcohol has been called vegetable fibrin1 and the soluble part is subdivided into two portions1 one unicedin or vegetable unicin1 and the other glutin 7gliadin7 or vegetable gelatin4 ,gluten1 according to some authorities1 does not properly exist in wheat flour1 but is formed therein by the action of water and certain ferments from free existing proteids4 ,a better explanation of the composition of gluten is that of ,osborne1 which will be given further on4 #cgb4 ,albuminoids4--,in this paragraph the term albuminoids is not employed as synonymous with proteids but as characteristic of a class of bodies nearly resembling them1 but1 nevertheless1 differing from them in many important particulars4 ,following is an abstract of their classification as given in ,watt's dictionary4#cdj ,collagen4--,the nitrogenous portions of connective tissues are largely composed of collagen4 ,by boiling water it is converted into gelatin4 ,it may be prepared from tendons as follows3 ,the tendinous tissues are shredded as finely as possible and extracted with cold water to remove the soluble proteids4 ,thereafter they are subjected for several days to the action of lime water1 which dissolves the cement holding the fibers together4 ,the residual insoluble matter is washed with water1 weak acetic acid1 and again with water4 ,the residue is chiefly collagen1 mixed1 however1 with some elastin and nuclein4 ,with dilute acids and alkalies collagen swells up after the manner of fibrin4 ,the organic nitrogenous matter of bone consists largely of collagen1 which is sometimes called ossein4 ,gelatin4--,when the white fibers of collagen1 obtained as above1 are subjected to the action of boiling water or of steam under pressure they dissolve and form gelatin4 ,isinglass is a gelatin made from the swimming bladder of the sturgeon or other fish4 ,glue is an impure gelatin obtained from hides and bones4 ,pure gelatin may be prepared from the commercial article by removing all soluble salts therefrom by treatment with cold water1 dissolving in hot water and filtering into ninety per cent alcohol4 ,the gelatin separates in the form of white filaments and these are removed and dried4 ,gelatin is insoluble in cold but soluble in hot water4 ,it is insoluble in alcohol1 ether and chloroform4 ,its hot aqueous solutions deflect the plane of polarized light to the left4 ,its gyrodynat varies with temperature and degree of dilution and is also influenced by acids and alkalies4 ,at #cj it is ,d -#acj4 ,gelatin is not precipitated by acetic acid nor lead acetate solution1 in which respect it differs from chondrin4 ,if boiled for a day1 or in a short time if heated to #adj in a sealed tube1 gelatin loses its power of setting and is split up into two peptonoid bodies1 semi-glutin and hemi-collin4 ,gelatin is easily digested but cannot take the place of other proteids in nutrition4 ,mucin4--,this albuminoid1 together with globulin1 forms the principal part of connective tissue4 ,it is also present in large quantities in mucus and is the chief lubricant of mucous membranes4 ,it is extremely difficult to prepare mucin in a state of purity1 and it is not certain that it has ever been accomplished4 ,it is precipitated but not rendered subsequently insoluble by sodium chlorid1 magnesium sulfate and alcohol4 ,when boiled with sulfuric acid it yields leucin and tyrosin and1 with caustic soda1 pyrocatechin4 ,met- and ,paralbumin4--,metalbumin is a form of mucin and differs from paralbumin by giving no precipitate when boiled4 ,both bodies yield reducing sugars when boiled with dilute sulfuric acid4 ,nuclein4--,the nitrogenous matters which form the nuclei of the ultimate cells are called nuclein4 ,nuclein resembles mucin in many physical properties but contains phosphorus4 ,it is also1 like mucin1 resistant to pepsin digestion4 ,the nuclein of eggs and milk probably contains iron4 ,nuclein is found also in cells of vegetable origin and in yeast and mildew4 ,nucleoproteids4--,these are bodies which yield both nuclein and albumin when boiled with water or treated with dilute acids or alkalies4 ,many nucleoproteids have the physical properties of mucus and the sliminess of the bile and of the synovial liquid is due to them4 ,they are the chief nitrogenous constituent of all protoplasm4 ,chondrin4--,chondrin is obtained from cartilage by boiling with water4 ,the solutions of chondrin set on cooling in the manner of gelatin4 ,they are precipitated by the same reagents used for throwing out gelatin and mucin4 ,chondrin is also levorotatory4 ,by some authorities chondrin is regarded as a mixture of gelatin and mucin4 ,elastin4--,the elastic fibers of connective tissue are composed of this material4 ,it can be prepared from the neck muscles by boiling with ether and alcohol to remove fats and then for a day and a half with water to extract the collagens4 ,the residue is boiled with strong acetic acid and thereafter with strong soda until the fibers begin to smell4 ,it is then treated with weak acetic acid and for a day with dilute hydrochloric acid4 ,the acid is removed by washing with water and the residue is elastin4 ,there is no solvent which acts on elastin without decomposing it4 ,it is digested by both pepsin and trypsin with the formation of peptones4 ,keratin4--,this nitrogenous substance is found chiefly in hairs1 nails1 and horns4 ,it is essentially an alteration proteid product due to peripheral exposure4 ,it is prepared by digesting the fine ground material successively with ether1 alcohol1 water and dilute acids4 ,the residue is keratin4 ,an imperfect aqueous solution may be secured by heating for a long time under pressure to #bjj4 ,it is also dissolved by boiling the materials mentioned above with alkalies1 and when the solution thus obtained is treated with water1 hydrogen sulfid is evolved1 showing that the sulfur of the molecule is loosely combined4 ,horn swells up when treated with dilute acetic acid and dissolves in the boiling glacial acid4 ,when treated with hot dilute sulfuric acid it yields aspartic and volatile fat acids1 leucin and tyrosin4 ,keratin1 when burning1 gives off a characteristic odor as is perceived in burning hair4 ,other ,albuminoids4--,among the albuminoids of less importance may be mentioned neurokeratin found in the medullary sheath of nerve fibers2 chitin occurring in the tissues of certain invertebrates2 conchiolin1 found in the shells of mussels and snails2 spongin1 occurring in sponges2 fibroin forming silk and spiders webs2 and hyalin or hyalogen found in edible birds' nests4 ,the nitrogenous bases in flesh which are soluble in cold water1 viz41 kreatin1 kreatinin1 carnin1 sarkin and xanthin are not classed among the albuminoid bodies1 since they have a much higher percentage of nitrogen than is found in true proteid bodies1 and are further differentiated from them by the absence of sulfur4 #cgc4 ,other ,forms of ,nitrogen4--,in addition to the proteids and albuminoids mentioned above1 agricultural products may contain nitrogen in the form of ammonia1 amid nitrogen and nitric acid4 ,the quantities of nitrogen thus combined are not large but often of sufficient magnitude to demand special study4 ,in general1 these bodies belong to transition products1 representing stages in the transfer of nitrogen from the simple to complex forms of combination1 or the reverse4 ,for instance1 the nitrogen which finally appears in the proteids of a plant has entered its organism chiefly as nitric acid1 and the nitric acid which is found in a vegetable product is therefore a representative of the quantity of unabsorbed nitrogen present in the tissues at the moment when the vital activity of the plant is arrested4 ,in some instances1 it is found that the absorption of nitrates by vegetable tissues takes place in far larger quantities than is necessary for their nutrition1 and in these cases the excess of nitrates accumulates1 sometimes to a remarkable extent4 ,in a case cited in the reports of the ,kansas ,agricultural ,experiment ,station1 where ,indian corn was grown on ground which had been used for a hog pen1 the quantity of potassium nitrate found in the dried stalks was somewhat remarkable4 ,when one of the stalks was cut in two and tapped lightly upon a table1 crystals of potassium nitrate were easily obtained in the form of fine powder4 ,on splitting the cornstalk the crystals in the pith could be seen without the aid of a microscope4 ,on igniting a piece of the dried stalk it burned rapidly with deflagration4 ,the percentage of potassium nitrate in the dried material was #ah4h4 ,cattle eating this fodder were poisoned4#cda ,in preserved meat products large quantities of oxidized nitrogen are often found1 and these come from the use of potassium nitrate as a preserving and coloring agent4 ,ammonia is rarely found in vegetable tissues in greater quantities than mere traces1 but may often exist in weighable amounts in animal products4 ,amid nitrogen is found rather constantly associated with proteid matters in vegetable products4 ,asparagin and glutamin are instances of amid bodies of frequent occurrence4 ,betain and cholin are found in cottonseed4 ,the occurrence of nitrogen1 in the form of alkaloids1 is of interest to agricultural chemists in this country1 chiefly from its presence as nicotin in tobacco and from a toxicological point of view1 but in other localities the production of alkaloids1 as for instance in opium1 tea and coffee1 is a staple agricultural industry4 ,the methods of separating and determining these forms of nitrogen will be given further on4 ,this description can evidently not include an extended compilation of the methods of separating and determining alkaloidal bodies1 with the exception of those with which the agricultural analyst will be called upon frequently to deal1 viz41 nicotin and caffein and nitrogenous bases such as betain and cholin4 ,,qualitive ,,tests ,,for ,,nitrogenous ,,bodies4 #cgd4 ,nitric ,acid4--,any nitric acid or nitrate which an agricultural product may contain may be leached out by treating the fine-ground material with cold water4 ,from vegetable matters this extract is evaporated to a small bulk1 filtered1 if necessary1 and tested for nitric acid by the usual treatment with ferrous sulfate and sulfuric acid4 ,in the case of vegetable substances there will not usually be enough of organic matter to interfere with the delicacy of the reaction1 but in animal extracts this may occur4 ,colored extracts should be decolorized with animal char 7bone-black7 before they are subjected to examination4 ,it is not well to attempt to remove the organic matters1 but1 since they are more insoluble in water than the nitrates1 the solution containing both may be evaporated to dryness and treated with a quantity of cold water insufficient for complete solution4 ,the nitrates will be found in the solution obtained in a larger proportionate quantity than before4 #cge4 ,amid ,nitrogen4--,one or more atoms of the hydrogen in ammonia may be replaced by acid or basic bodies 7alcohol radicles74 ,in the former cases amids1 in the latter amins result4 ,in the ratio of displacement there are formed primary1 secondary1 and tertiary bodies determined by the number of hydrogen atoms replaced4 ,the primary amids are the only ones of these bodies that are of interest in this connection4 ,the amids are easily decomposed1 even on heating with water and the more readily with acids and alkalies1 the amido radicle being converted into ammonia4 ,a type of these reactions is given below4 ,,ch4,,co4,,nh ,h,o ,,ch4,,co4,,oh ,h,n4 ,on boiling an amid with hydrochloric acid1 the ammonia is procured as chlorid whence it is easily expelled by heating with an alkali4 ,in a body free of ammonia1 an amid is easily detected by subjecting the substance containing it to the action of hot hydrochloric acid1 filtering1 neutralizing the free acid with sodium hydroxid1 adding an excess thereof and distilling into an acid4#cdb ,in case the quantity of ammonia produced is very small it may be detected by the nessler reagent4#cdc ,amids are soluble in a fresh1 well washed preparation of cupric hydrate suspended in water4 ,the hydrate also passes into solution forming a liquid of a deep blue color4 ,if amids be added to a cold solution of potassium nitrate in sulfuric acid free nitrogen is evolved4 #cgf4 ,ammoniacal ,nitrogen4--,this combination of nitrogen may be detected by distilling the sample1 or an aqueous extract thereof1 with magnesia or barium carbonate4 ,the ammonia is collected in an acid and detected therein by the usual qualitive reactions4 #cgg4 ,proteid ,nitrogen4--,there are a few general qualitive reactions for proteid nitrogen and some special ones for distinct forms thereof4 ,below will be given a few of those reactions which are of most importance to the agricultural analyst3 ,conversion into ,ammonia4--,all proteid matters are converted into ammonia on boiling with strong sulfuric acid in presence of an oxygen carrier4 ,mercury is the substance usually selected to effect the transfer of the oxygen4 ,bodies which are found to be free of nitrates1 ammonia and amids1 are subjected directly to oxidation with sulfuric acid1 and the ammonia produced thereby is distilled and detected in the manner already suggested4 ,if nitrogen be present in the form of ammonia1 amids and nitrates1 the substance may be heated with an acid1 hydrochloric or acetic1 thrown on a filter1 washed with hot dilute acid and the residue tested as above for proteid nitrogen4 ,biuret ,reaction4--,when proteid matter is dissolved in sulfuric acid1 the solution1 made alkaline with potassium hydroxid and treated with a few drops of a solution of copper sulfate1 gives a violet coloration4 ,this is commonly known as the biuret reaction1 because the substance ,c,h,n,o1 biuret1 left on heating urea to #afj gives the coloration noted in the conditions mentioned4 ,it has been found by ,bigelow1 in this laboratory1 that if a solution is to be examined containing a very small amount of a proteid or similar body1 the copper sulfate solution should not contain more than four grams of ,cu,s,o4#e;,h,o in #ajj cubic centimeters of water1 and the test should first be made by adding to the solution one or two drops of this copper sulfate solution1 and then a strong excess of potassium or sodium hydroxid4 ,the test may be repeated1 using from one-half to two cubic centimeters of the copper sulfate solution1 according to the amount of proteid present4 ,if too much of the copper sulfate solution be employed its color may conceal that of the reaction4 ,heating to the boiling point sometimes makes the violet color more distinct4 ,if a solid is to be examined it is first suspended in water1 and in this state treated in the same manner as a solution4 ,if solution is not complete1 the mixture should be filtered when the color produced may be observed in the filtrate4 ,proteoses and peptones give a red to red-violet and other proteids a violet to violet-blue coloration4 ,xanthoproteic ,reaction4--,strong nitric acid produces a yellow coloration of proteid matter1 which is intensified on warming4 ,on treating the yellow mixture with ammonia in slight excess the color is changed to an orange or red tint4 #cgh4 ,qualitive ,tests for ,albumin4--,albumin is one of the chief proteids and exists in both animal and vegetable substances4 ,it is soluble in cold water and may therefore be separated from many of its nearly related bodies which are insoluble in that menstruum4 ,in aqueous solutions its presence may be determined by the general reactions for proteid matters given above or by the following tests3 ,precipitation by ,heat4--,albumin is coagulated by heat4 ,vegetable albumins become solid at about #fe and those of animal origin at a somewhat higher temperature 7#ge74 ,some forms of animal albumin1 however1 as for instance that contained in the serum1 coagulate at a lower temperature4 ,precipitation by ,acids4--,dilute acids also precipitate albumins especially with the aid of heat4 ,practically all the albumins are thrown out of solution by application of heat in the presence of dilute acids4 ,mercuric ,salts4--,acid mercuric nitrate and a mixture of mercuric chlorid1 potassium iodid and acetic acid completely precipitate all albuminous matters4#cdd ,the yellow or red color produced on heating albumin with the mercuric nitrate is known as ,million's reaction4 #cgi4 ,qualitive ,test for ,peptones and ,albuminates4--,when peptones and albuminates are dissolved in an excess of glacial acetic acid and the solution treated with sulfuric acid a violet color is produced and also a faint fluorescence4 ,separation of ,peptones and ,albumoses4--,in a solution of peptones and albumoses the latter may be precipitated by saturating the solution with finely powdered zinc or ammonium sulfate4 ,action of ,phosphotungstic ,acid4--,all proteid matters in aqueous1 alkaline or acid solutions1 are precipitated by sodium phosphotungstate in a strongly acid solution4 ,acetic1 phosphoric1 or sulfuric acid may be used for producing the required acidity1 preference being given to the latter4 ,action of ,trichloracetic ,acid4--,in the precipitation of albumin by trichloracetic acid1 there is formed a compound of the two bodies which to #ajj parts of albumin has #bf4h parts of the trichloracetic acid4 ,the different albuminoid bodies obtained by precipitation behave in a similar manner4 ,there are formed flocculent precipitates insoluble both in dilute and concentrated acids in the cold and also at a high temperature1 with the exception of the hemialbumose compound4#cde ,albumin peptone1 however1 gives with the acid named in concentrated solution a precipitate easily soluble in an excess of the reagent4 ,in the analysis of cow's milk but not of human milk1 this acid can be used for the estimation of the albuminoid substances4 ,with both kinds of milk it can be used for the estimation of the albumin after the removal of the casein4 ,after precipitation of the albuminoid bodies1 the milk sugar can be estimated by polarizing the filtrate and1 volumetrically after removal of the excess of the acid by evaporation4 ,by means of trichloracetic acid it is possible to separate albumin peptone from mucus and mucus peptone4 ,a similar reaction is also produced by dichloracetic acid1 but the reaction with this last agent is less delicate than with the other4 ,neither mucus nor albumin is precipitated by chloracetic acid4 #chj4 ,action of ,albumins on ,polarized ,light4--,many of the albumins and albuminates1 when in solution1 strongly deflect the plane of polarized light to the left4#cdf ,the gyrodynats of some of the albumins and albuminates are given below3 ,serum albumin ,d -#eg4c to -#fd4f4 ,egg albumin ,d -#ce4e to -#ch4a4 ,serum globulin ,d -#dg4h4 ,milk albumin ,d -#gf4j to -#ia4j4 ,our knowledge of the gyrodynatic numbers of the proteids and allied bodies is too fragmentary to be of any great help in analytical work4 ,in practice1 the rotatory power of these bodies becomes a disturbing force in the determination of milk sugar4#cdg ,a further study of this property of certain proteids may lead to analytical processes for their detection and determination1 but no reliable methods for this can now be recorded4 #cha4 ,alkaloidal ,nitrogen4--,only a general statement can be made here in respect of the detection of alkaloidal nitrogen in vegetable or animal tissues4 ,alkaloids are not found in healthy animal tissues and the description of methods for isolating and detecting ptomaines is foreign to the purpose of this work4 ,in vegetable tissues the presence of alkaloids may be established by the following methods of examination4 ,the fine-ground tissues are made to pass a sieve of half millimeter mesh and when suspended in water are acidified with sulfuric4 ,the mixture is then thoroughly extracted by shaking in a separatory funnel with petroleum ether1 benzene and chloroform1 successively4 ,some resins1 glucosids and a few alkaloidal bodies not important here are extracted by this treatment4 ,the residue is made distinctly alkaline with ammonia and treated as above with the same solvents4 ,in the solution obtained as last mentioned nearly all the alkaloidal bodies found in plants are contained4 ,all the alkaloids in a plant may be obtained by digesting the finely divided material with dilute sulfuric acid4 ,the acid solution thus obtained is made nearly neutral with ammonia or magnesia1 concentrated to a sirup1 and gums1 mucilage1 etc4 thrown out by adding about three volumes of ninety-five per cent alcohol4 ,the alkaloids are found in the filtrate4 ,the alcohol is evaporated from the filtrate and the residue tested for alkaloids by group reagents4#cdh ,potassium mercuric iodid and phosphotungstic and molybdic acids are types of these reagents4 ,the same group reagents may also be applied to the extracts obtained with petroleum ether1 benzene and chloroform1 in all cases1 after the removal of the solvents by evaporation4 ,,estimation ,,of ,,nitrogenous ,,bodies ,,in ,,agricultural ,,products4 #chb4 ,total ,nitrogen4--,any one of the methods heretofore described for the estimation of total nitrogen in soils or fertilizers is applicable for the same purpose to agricultural products4 ,one among these1 however1 is so superior in the matter of convenience and certainty1 as to make it preferable to any other4 ,the moist combustion of the sample with sulfuric acid with subsequent distillation of the ammonia produced is the process which is to be recommended4#cdi ,the usual precautions for securing a representative sample should be observed1 but no further directions are needed4 ,in all cases hereafter1 where the estimation of nitrogen is enjoined1 it is understood that the moist combustion process is to be used unless otherwise stated4 #chc4 ,estimation of ,ammoniacal ,nitrogen4--,if the distillation of ammonia be accomplished with the aid of magnesia alba or barium carbonate it may be safely conducted on the finely ground materials or1 in case of animal bodies1 in as fine a state of subdivision as may be conveniently secured4 ,since the salts of ammonia are easily soluble in water they may be all obtained in aqueous solution1 and the distillation of this solution with magnesia gives correct results4 ,experience has shown that the stronger alkalies1 such as sodium and potassium hydroxids1 cannot be safely used in the distillation of ammonia from mixtures containing organic nitrogenous materials because of the tendency of these bodies to decomposition1 in the circumstances1 yielding a portion of their nitrogen as ammonia4 ,barium carbonate acts with less vigor on non-ammoniacal nitrogenous matters than magnesia1 and in some cases1 as pointed out further on1 may be substituted therefor with advantage4 ,there is no danger of failing to obtain a part of the ammonia on distillation with magnesia provided the latter does not contain more than a trace of carbonate4#cej ,when no easily decomposable organic nitrogenous matters are present1 the distillation may be conducted with the stronger alkalies in the manner prescribed4#cea ,all the necessary details of conducting the distillation are found in the preceding volumes of this work4 #chd4 ,estimation of ,amid ,nitrogen4--,in bodies containing no ammonia1 or from which the ammonia has been removed by the method described in the preceding paragraph1 the nitrogen in the amid bodies is converted into ammonia by boiling for about an hour with five per cent sulfuric or hydrochloric acid4 ,the ammonia thus produced is estimated in the usual manner after distillation over magnesia free of carbonate4 ,the free acid is exactly neutralized with sodium or potassium carbonate before the addition of the magnesia4 ,the results are given in terms of asparagin4 ,the reaction which takes place in the decomposition of the amid body is indicated by the following equation3 ,asparagin4 ,sulfuric ,aspartic ,ammonium acid4 acid4 sulfate4 #b;,c,h,n,o #b;,h,o ,h,,so #b;,c,h,,no 7,h,n7,,so4 ,half of the nitrogen contained in the amid body is thus obtained as ammonia4 ,it is advisable to calculate all the amid nitrogen in agricultural products as asparagin4 #che4 ,sachsse's ,method4--,a method for the determination of amid bodies by liberation of free nitrogen has been described by ,sachsse and ,kormann4#ceb ,it is based on the reaction which takes place when amid bodies are brought into contact with nitrites in presence of an acid4 ,the mixture of the reagents by which the gas is set free is accomplished in the apparatus shown in ,fig4 #ajc4 ,the vessel ,a has a capacity of about fifty cubic centimeters and carries a stopper with three perforations for the arrangement shown4 ,illustration3 ,,fig4 #ajc4--;,,apparatus ,,for ,,amid ,,nitrogen4 ,illustration3 ,,fig4 #ajd4--,,sachsse',s ,,eudiometer4 ,about six cubic centimeters of a concentrated aqueous solution of potassium nitrite are placed in ,a and the lower parts of the tubes a and b are filled with water to a little above e in order to exclude the air therefrom4 ,dilute sulfuric acid is placed in one of the funnels and an aqueous solution of the amid in the other4 ,the air is displaced from the empty part of ,a by introducing the sulfuric acid1 a little at a time1 whereby nitrous acid and nitric oxid are evolved4 ,this operation is continued until all the air has been driven out through c d1 the open end of d being kept in the liquid in the dish shown in ,fig4 #ajd4 ,the eudiometer in which the evolved nitrogen is measured is shown in ,fig4 #ajd1 and should have a capacity of about fifty cubic centimeters1 and be graduated to fifths4 ,it is filled with the solution of ferrous sulfate contained in ,b by sucking at g1 after which the clamp h is replaced1 the cock f closed1 and the free end of d placed in the lower end of the eudiometer4 ,the solution of the amid is run slowly into the generator ,a1 ,fig4 #ajc1 together with small additional quantities of the sulfuric acid when the evolution of gas becomes slow4 ,from time to time h is opened and fresh quantities of the ferrous solution allowed to flow into the eudiometer4 ,any trace of the amid remaining in the funnel is washed into ,a with pure water1 with care to avoid the introduction of air4 ,when the liquid in ,a assumes a permanent blue color the decomposition is complete4 ,the residual gas is driven out of ,a by filling with water4 ,the tubes d and h1 after all the nitric oxid is absorbed1 are removed from the eudiometer which is transferred to a cylinder containing water and immersed therein until the two liquid surfaces are at the same level and the volume of the nitrogen observed4 ,after correction for temperature and pressure1 the weight of the nitrogen is calculated4 ,twenty-eight parts by weight of nitrogen correspond to #aej of pure asparagin1 #aha of tyrosin and #aca of leucin4#cec ,this method of procedure is difficult of manipulation and is apt to give results that are too high4 ,it cannot be preferred to the more simple and accurate processes already described4 #chf4 ,preparation of ,asparagin4--,in case the analyst desires to prepare a quantity of asparagin for comparative purposes it may be easily accomplished in the following way3 ,a sufficient quantity of pease or beans is sprouted in a dark place and allowed to grow until the reserve food of the seed is exhausted4 ,the young sprouts are gathered1 shredded and subjected to strong pressure4 ,the juice thus obtained is boiled to coagulate the albumin1 and thrown on a filter4 ,the filtrate is evaporated to a thin sirup and set aside to allow the asparagin to separate in a crystallized form4 ,if the crystals at first formed are colored they may be dissolved1 decolorized with bone-black1 and recrystallized4 ,instead of the above method the young shoots may be shredded1 extracted with hot water and the extract treated as above4 ,a larger yield of the asparagin is obtained by the latter process than by the one mentioned above4#ced #chg4 ,detection and ,estimation of ,asparagin and ,glutamin4--,of all the amid bodies asparagin is the most important from an agricultural standpoint1 because of its wide distribution in vegetable products4#cee ,asparagin is easily obtained from the aqueous extracts of plants by crystallization4#cef ,in addition to its crystalline characteristics asparagin may be identified by the following tests4 ,heated with alkalies1 including barium hydroxid1 asparagin yields ammonia4 ,boiled with dilute acids it forms ammonium salts4 ,a warm aqueous solution dissolves freshly prepared copper hydroxid with the production of a deep blue color4 ,sometimes1 on cooling1 crystals of the copper compound formed are separated4 ,asparagin crystallizes with one molecule of water4 ,glutamin gives essentially the reactions characteristic of asparagin1 but crystallizes without water in small white needles4 ,asparagin is easily detected with the aid of the microscope by placing sections of vegetable tissues containing it in alcohol4 ,after some time microscopic crystals of asparagin are separated4 ,the presence of large quantities of soluble carbohydrates seriously interferes with the separation of asparagin in crystalline form4 ,for the detection of glutamin the liquid containing it is boiled with dilute hydrochloric acid1 by which ammonia and glutamic acid are formed4 ,on the addition of lead acetate to the solution the glutamic acid is thrown out as a lead salt1 in which1 after its decomposition with hydrogen sulfid1 the characteristic properties of glutamic acid can be established4 ,the above process is chronophagous and also uncertain where the quantity of glutamin is very small and that of other soluble organic matters very large4 ,a much better process1 both for the detection of glutamin and asparagin1 is the following1 based on the property possessed by mercuric nitrate of precipitating amids4 ,the aqueous extract containing the amid bodies is mixed with lead acetate until all precipitable matters are thrown out and the mixture poured into a filter4 ,to the filtrate is added a moderately acid solution of mercuric nitrate4 ,the precipitate produced is collected on a filter1 washed1 suspended in water1 decomposed with hydrogen sulfid and again filtered4 ,the amid bodies 7glutamin1 asparagin1 etc47 are found in the filtrate and can be detected and estimated by the processes already described4 ,a reaction showing the presence of an amid body is not a positive proof of the presence of asparagin or glutamin1 since among other amids1 allantoin may be present4 ,this substance is found in the sprouts of young plants and also in certain cereals1 as shown by researches in this laboratory4#ceg ,allantoin1 glutamin1 and asparagin1 when obtained in solution by the above process1 may be secured1 by careful evaporation and recrystallization1 in well defined crystalline forms4 ,asparagin gives lustrous1 rhombic prisms1 easily soluble in hot water1 but insoluble in alcohol and ether4 ,allantoin is regarded as a diureid of glyoxalic acid and has the composition represented by the formula ,c,h,n,o4 ,it crystallizes in lustrous prisms having practically the same solubility as asparagin4 ,glutamin is the amid of amidoglutaric acid4 ,it crystallizes in fine needles4 ,its structural formula is represented as ,,co4,,nh _/ ,c,h7,,nh7 ,,co,h4 #chg4 ,cholin and ,betain4--,cholin is a nitrogenous base found in both animal and plant tissues4 ,its name is derived from the circumstance that it was first discovered in the bile4 ,it is found in the brain1 yolk of eggs1 hops1 beets1 cottonseed and many other bodies4 ,when united with glycerolphosphoric acid it forms lecithin1 a compound of great physiological importance4 ,from a chemical point of view1 cholin is oxyethyltrimethyl-ammonium hydroxid1 ,,oh _/ ,c,h 2 7,c,h,,no74 ,n7,,ch74,,oh ,it is crystallized with difficulty and is deliquescent4 ,its most important compound1 from an analytical point of view1 is its platinum salt ,c,h,o,n,cl,pt,cl4 ,this salt crystallizes in red-yellow plates and is insoluble in alcohol4 ,betain1 ,c,h,,no1 is the product of the oxidation of cholin4 ,in this laboratory the bases are separated from cottonseed and from each other by the process described below4#ceh ,about five pounds of fine-ground cottonseed cake are extracted with seventy per cent alcohol4 ,the material should not be previously treated with dilute mineral acids because of the danger of converting a part of the cholin into betain4 ,the alcohol is removed from the filtered extract and the residue dissolved in water4 ,the aqueous solution is treated with lead acetate until no further precipitation takes place1 thrown on a filter1 the lead removed from the filtrate with hydrogen sulfid and the liquid evaporated to a viscous syrup4 ,the sirup is extracted with alcohol containing one per cent of hydrochloric acid4 ,the solution thus obtained is placed in a deep beaker and the bases precipitated by means of an alcoholic solution of mercuric chlorid4 ,the complete separation of the salts requires at least two weeks4 ,the double salts of the bases and mercury thus obtained1 after freeing from the mother liquor1 are recrystallized from a solution in water and from the pure product thus obtained the mercury is removed after solution in water1 by hydrogen sulfid4 ,the filtrate1 after separating the mercury1 contains the bases as chlorids 7hydrochlorates74 ,the solution of the chlorids is evaporated slowly in 7pene7 vacuo to a thick sirup and set over sulfuric acid to facilitate crystallization4 ,the hydrochlorates are obtained in this way colorless and in well-shaped crystalline forms4 ,in a quantitive determination1 a small amount of the fine meal is extracted at once with one per cent hydrochloric acid in seventy per cent alcohol1 the salts obtained purified as above and weighed4 ,the following process serves to determine the relative proportions of cholin and betain in a mixture of the two bases4 ,a definite weight of the chlorids1 prepared as directed above1 is extracted by absolute alcohol4 ,this treatment dissolves all the cholin chlorid and a little of the betain salt4 ,the alcoholic solution is evaporated and again extracted with absolute alcohol4 ,this process is repeated three times and at the end the cholin chlorid is obtained free of betain4 ,in a sample of cottonseed cake examined in this laboratory the two bases were found present in the following relative proportions1 viz41 cholin #ag4e per cent1 betain #hb4e per cent4 ,thus purified the cholin is finally precipitated by platinum chlorid4 ,for a description of the special reaction1 by means of which cholin and betain are differentiated1 the paper cited above may be consulted4 ,these bodies have acquired an economic interest on account of their occurrence in cottonseed meal1 which is so extensively used as a cattle food4 ,it is evident from the relative proportions in which they occur that the less nocuous base1 betain1 is the more abundant4 ,it is possible1 however1 that the base originally formed is cholin and that betain is a secondary product4 ,experience has shown that it is not safe to feed cottonseed meal to very young animals1 while moderate rations thereof may be given to full-grown animals without much expectation of deleterious results4 ,in the case of toxic effects it is fair to presume that a meal has been fed in which the cholin is relatively more abundant than the betain4 #chi4 ,lecithin4--,lecithin is a nitrogenous body1 allied both to the fats and proteids and containing glycerol and phosphoric acid4 ,its percentage composition is represented with some accuracy by the formula ,c,h,,npo1 or according to ,hoppe-,seyler1 ,c,h,,npo4 ,it appears to be a compound of cholin with glycerolphosphoric acid4 ,it is widely distributed both in animal and vegetable organisms1 in the latter especially in pease and beans4 ,from a physiological point of view1 lecithin is highly important as the medium for the passage of phosphorus from the organic to the inorganic state1 and the reverse4 ,this function of lecithin has been thoroughly investigated in this laboratory by ,maxwell4#cei ,in the extraction of lecithin from seeds 7pease1 beans1 etc47 it is not possible to secure the whole of the substance by treatment with ether alone4#cfj ,the extraction of the lecithin may1 however1 be entirely accomplished by successive treatments for periods of about fifteen hours with pure ether and alcohol4 ,this is better than to mix the solvents1 since1 in this case1 the ether having the lower boiling point is chiefly active in the extraction4 ,when the extraction is accomplished by digestion and not in a continuous extracting apparatus the two solvents may be mixed together and thus used with advantage4 ,after the evaporation of the solvents1 the lecithin is ignited with mixed sodium and potassium carbonate whereby the organic phosphorus is secured without loss in an inorganic form4 ,where greater care is desired1 the method described for organic phosphorus in soils may be used4#cfa ,the inorganic phosphorus thus obtained is estimated in the usual way as magnesium pyrophosphate4 ,for analytical purposes1 the extraction of lecithin from vegetable substances is conducted in this laboratory as follows3#cfb ,the fine-ground pea or bean meal is placed in an extraction apparatus and treated continuously with anhydrous ether for fifteen hours4 ,the ether in the apparatus is replaced with absolute alcohol and the extraction continued for six hours longer4 ,the alcoholic extract is evaporated to dryness and treated with ether4 ,the part of the lecithin at first insoluble in ether becomes soluble therein after it has been removed from the vegetable tissues by alcohol4 ,moreover1 any trace of inorganic phosphorus which may have been removed by the alcohol1 is left undissolved on subsequent treatment with ether4 ,the ether extract from the alcohol residue is added to that obtained directly1 the ether removed by evaporation1 and the total lecithin oxidized and the residue used for the estimation of phosphorus as already described4 ,in determining the lecithin in eggs1 the procedure employed for vegetable tissues is slightly changed4#cfc ,the whole egg1 excluding the shell1 is placed in a flask with a reflux condenser and boiled for six hours with absolute alcohol4 ,the alcohol is then removed from the flask by evaporation and the residue treated in like manner with ether for ten hours4 ,the ether is removed and the dry residue rubbed to a fine powder1 placed in an extractor and treated with pure ether for ten hours4 ,the extract thus secured is oxidized after the removal of the ether by fusion with mixed alkaline carbonates and the phosphorus determined in the usual way4 #cij4 ,factor for ,calculating ,results4--,the percentage of lecithin is calculated from the weight of magnesium pyrophosphate obtained by multiplying it by the factor1 #g4bgjc4cfd ,this factor is calculated from the second formula for lecithin given above1 in which the percentage of phosphorus pentoxid1 ,p,o1 is #h4ghi4 ,example4--,in fifty-four grams of egg1 exclusive of the shell1 is found an amount of organic phosphorus yielding #j4jhdh gram of magnesium pyrophosphate4 ,then #j4jhdh #g4bgjc #j4fafeb and #j4fafeb #ajj #ed #a4ad4 ,therefore the percentage of lecithin in the egg is #a4ad4 #cia4 ,estimation of ,alkaloidal ,nitrogen4--,the alkaloids contain nitrogen in a form more difficult of oxidation than that contained in proteid or albuminoid forms4 ,it is doubtful whether any of the nitrogen in alkaloids becomes available for plant nutrition by any of the usual processes of fermentation and decay to which nitrogenous bodies are submitted in the soil4 ,likewise1 it is true that it is not attacked by the digestive processes in any way preparatory to its assimilation as food by the animal tissues4 ,alkaloidal nitrogen is therefore not to be regarded as a food either for the animal or plant4 ,for the general methods of estimating alkaloids the reader is referred to standard works on plant chemistry and toxicology4 ,the alkaloids of interest in this manual are those which are found in tobacco1 tea1 coffee and a few other products of agricultural importance4 ,the best methods of isolating and estimating these bodies will be given in the part of the volume devoted to the special consideration of the articles mentioned4 ,,separation ,,of ,,proteid ,,bodies ,,in ,,vegetable ,,products4 #cib4 ,preliminary ,treatment4--,the chief disturbing components of vegetable tissues1 in respect of their influence on the separation and estimation of the proteid constituents1 are fats and oils and coloring matters4 ,in many cases these bodies are present in such small quantities as to be negligible1 as1 for instance1 in rice4 ,in other cases they exist in such large proportions as to present almost insuperable difficulties to analytical operations1 as is the case with oily seeds4 ,in all instances1 however1 it is best to remove these bodies1 even when present in small proportions1 provided it can be done without altering the character of the proteid bodies4 ,this is secured by extracting the fine-ground vegetable material first with petroleum ether1 and afterwards with strong alcohol and ether4 ,practically1 all of the fatty bodies and the greater part of the most objectionable coloring matters are removed by this treatment4 ,the extraction should in all cases be made at low temperatures1 not exceeding #ce1 to avoid the coagulating effect of higher temperatures upon the albuminous bodies which may be present4 ,in this laboratory1 fatty seeds1 as for instance peanuts1 are first ground into coarse meal1 then extracted with petroleum ether1 ground to a fine meal and the fat extraction completed with petroleum ether1 ninety-five per cent alcohol and pure sulfuric ether4 ,the residue of the last solvent may be removed by aspirating air through the extracted meal4 ,in some cases1 it is advisable to extract with ethyl ether before as well as after the alcoholic extraction4 ,this treatment removes at least a part of the water and prevents the dilution of the first part of alcohol added to such an extent as to make it dissolve some of the proteid matters4 ,in each case1 a portion of the alcoholic extract should be tested qualitively for proteid matter4 ,if any be found1 stronger alcohol should be used for1 at least1 the first extraction4 ,a portion of the meal1 prepared as above directed1 is extracted with a ten per cent solution of sodium chlorid1 as described further on1 and a measured portion of the filtered extract diluted with water until the proteid matter in solution begins to be precipitated4 ,by this treatment the proper strength of the salt solution1 to be used for the subsequent extraction1 is determined4 ,to save time in dialyzing1 the solution of salt employed as a solvent should be as dilute as possible4 ,the mixture of meal and solvent sometimes filters with difficulty4 ,in these cases1 it is advisable to first pour it into a linen bag from which the liquid portion can be removed by gentle pressure and subsequently filtered through paper4 ,as a last resort1 the liquid secured from the linen filter can be saturated with ammonium1 zinc or magnesium sulfate1 whereby all the proteid matters are thrown out4 ,after filtering1 the residue is again dissolved in salt solution and can then be readily filtered through paper4 ,the clear filtrate should be tested by fractional precipitation by heat and the final filtrate by acetic acid1 as will be described further on4 ,the proteid matter may be further freed from amid compounds by treatment with copper sulfate4#cfe ,this treatment is not advisable1 however1 except for the purpose of determining the total proteid nitrogen in the sample4 ,the action of the water1 heat and cupric sulfate combined is capable of inducing grave changes in the character of the residual matter which would seriously interfere with the results of subsequent studies of the nature of the proteid bodies4 ,in many instances1 as with cereal grains1 the separation of the proteid bodies is accomplished by no further preliminary treatment than is necessary to reduce them to the proper degree of fineness4 #cic4 ,diversity of ,character4--,the proteids which occur in vegetable products are found in all parts of the tissues of the plants1 but in cereals especially in the seeds4 ,in grass crops and in some of the legumes1 such as clover1 the nitrogenous matters are chiefly found in the straw and leaves4 ,the general classification of these bodies has already been given1 but each kind of plant presents marked variations1 not only in the relative proportions of the different classes1 but also in variations in the nature of each class4 ,for this reason the study of vegetable proteids is1 in some respects1 a new research for each kind of plant examined4 ,there are1 however1 some general principles which the analyst must follow in his work1 and an attempt will be made here to establish these and to construct thereon a rational method of conducting the investigation4 ,in the separation and estimation of complex bodies so nearly related to each other1 it is difficult not only to secure satisfactory results1 but also to prevent the transformation of some forms of proteid matter into others nearly related thereto by the action of the solvents used for separation and precipitation4 #cid4 ,separation of ,gluten from ,wheat ,flour4--,the most important proteid in wheat is the body known as gluten1 a commercial name given to the nitrogenous matters insoluble in cold water4 ,the gluten thus obtained does not represent a single chemical compound1 but is a complex consisting of at least two proteid bodies1 which together form an elastic1 pasty mass1 insoluble in cold water containing a trace of mineral salts4 ,this mass has the property of holding mechanically entangled among its particles bubbles of gas1 which1 expanding under the action of heat during cooking1 give to bread made of glutenous flours its porous property4 ,in respect of proteids1 the ,american wheats1 as a rule1 are quite equal to those of foreign origin4 ,this is an important characteristic when it is remembered that both the milling and food values of a wheat depend largely on the nitrogenous matter which is present4 ,it must not be forgotten1 however1 that merely a high percentage of proteids is not always a sure indication of the milling value of a wheat4 ,the percentage of gluten to the other proteid constituents of a wheat is not always constant1 and it is the gluten content of a flour on which its bread making qualities chiefly depend4 ,the percentage of moist gluten gives1 in a rough way1 the property of the glutenous matter of absorbing and holding water under conditions as nearly constant as can be obtained4 ,in general1 it may be said that the ratio between the moist gluten and the dry gluten in a given sample is an index for comparison with other substances in the same sample4 ,upon the whole1 however1 the percentage of dry gluten must be regarded as the safer index of quality4 ,in respect of the content of glutenous matter1 our domestic wheats are distinctly superior to those of foreign origin4 ,they are even better than the ,canadian wheats in this respect4 ,it may be fairly inferred1 therefore1 that while our domestic wheats give a flour slightly inferior in nutritive properties to that derived from foreign samples1 it is nevertheless better adapted for baking purposes1 and this quality more than compensates for its slight deficiency in respect of nutrition1 a deficiency1 which1 however1 is so minute as to be hardly worth considering4#cff ,the gluten is separated in this laboratory from the other constituents of a flour by the following process3 ,ten grams of the fine-ground flour are placed in a porcelain dish1 well wet with nearly an equal weight of water at a temperature of not to exceed #ae1 and the mass worked into a ball with a spatula1 taking care that none of it adheres to the walls of the dish4 ,the ball of dough is allowed to stand for an hour1 at the end of which time it is held in the hand and kneaded in a stream of cold water until the starch and soluble matter are removed4 ,the ball of gluten thus obtained is placed in cold water and allowed to remain for an hour when it is removed1 pressed as dry as possible between the hands1 rolled into a ball1 placed in a flat bottom dish and weighed4 ,the weight obtained is entered as moist gluten4 ,the dish containing the ball of gluten is dried for twenty hours in a steam-bath1 again weighed1 and the weight of material obtained entered as dry gluten4 ,the determination of dry and moist gluten cannot in any sense be regarded as an isolation and estimation of a definite chemical compound4 ,for millers' and bakers' purposes1 however1 the numbers thus obtained have a high practical value4 ,a typical wheat grown in this country will contain about #bf4ej per cent of moist and #aj4be per cent of dry gluten4 ,the gluten of wheat is composed of two proteid bodies1 gliadin and glutenin4#cfg ,gliadin contains #ag4ff per cent1 and glutenin #ag4di per cent of nitrogen4 ,gliadin forms a sticky mass when mixed with water and is prevented from passing into solution by the small content of mineral salts present in the flour4 ,it serves to bind together the other ingredients of the flour1 thus rendering the dough tough and coherent4 ,glutenin serves to fix the gliadin and thus to make it firm and solid4 ,glutenin alone cannot yield gluten in the absence of gliadin1 nor gliadin without the help of glutenin4 ,soluble metallic salts are also necessary to the formation of gluten1 and act as suggested above1 by preventing the solution of the gliadin in water1 during the process of washing out the starch4 ,no fermentation takes place in the formation of gluten from the ingredients named4 ,the gluten1 which is obtained in an impure state by the process above described1 is1 therefore1 not to be regarded as existing as such in the wheat kernel or flour made therefrom1 but to arise by a union of its elements by the action of water4 #cie4 ,extraction with ,water4--,it is quite impossible to get an extract from fine-ground vegetable matter in pure water because the soluble salts of the sample pass at once into solution and then a pure water solvent becomes an extremely dilute saline solution4 ,the aqueous extract may1 however1 be subjected to dialysis1 whereby the saline matter is removed and the proteid matter1 not precipitated during the dialytic process1 may be regarded as that part of it in the original sample soluble in pure water4 ,nevertheless1 in many instances1 it is important to obtain an extract with cold water4 ,in oatmeal the aqueous extract is obtained by ,osborne as follows3#cfh ,five pounds of fine-ground meal are shaken occasionally with six liters of cold water for twenty-four hours1 the liquid removed by filtration and pressure and the extraction continued with another equal portion of water in the manner noted4 ,the two liquid extracts are united and saturated with commercial ammonium sulfate which precipitates all the dissolved proteid matter4 ,the filtrate obtained is collected on a filter1 washed with a saturated solution of ammonium sulfate and removed as completely as possible from the filter paper by means of a spatula4 ,any residual precipitate remaining on the paper is washed into the vessel containing the removed precipitate and the undissolved precipitate well beaten up in the liquid1 which is placed in a dialyzer with a little thymol1 to prevent fermentation1 and subjected to dialysis for about two weeks4 ,at the end of that time1 the contents of the dialyzer are practically free of sulfates4 ,the contents of the dialyzers are then thrown on a filter and in the filtrate are found those proteids first extracted with water1 precipitated with ammonium sulfate and redissolved from this precipitated state by pure water4 ,in the case of oatmeal1 this proteid matter is not coagulated by heat1 and may be obtained in the dry state by the evaporation of the filtrate last mentioned at a low temperature in vacuo4 ,it is evident that the character of the proteid matter thus obtained will vary with the nature of the substance examined4 ,in the case of oats1 it appears to be a proteose and not an albumin4 #cif4 ,action of ,water on ,composition of ,proteids4--,when a body1 such as oatmeal1 containing many proteids of nearly related character1 is exposed to the action of a large excess of water1 the proteid bodies may undergo important changes whereby their relations to solvents are changed4 ,after oatmeal has been extracted with water1 as described above1 the proteid matter originally soluble in dilute alcohol undergoes an alteration and assumes different properties4 ,the same remark is applicable to the proteid body soluble in dilute potash4 ,nearly all the proteid matter of oatmeal is soluble in dilute potash1 if this solvent be applied directly1 but if the sample be previously treated with water or a ten per cent salt solution the subsequent proportion of proteid matter soluble in dilute potash is greatly diminished4#cfi ,water applied directly to the oatmeal apparently dissolves an acid albumin1 a globulin or globulins1 and a proteose4 ,the bodies1 however1 soluble in water1 exist only in small quantities in oatmeal4 ,experience has shown that in most instances1 it is safer to begin the extraction of a cereal for proteid matter with a dilute salt solution rather than with water1 and to determine the matters soluble in water alone by subsequent dialysis4 #cig4 ,extraction with ,dilute ,salt ,solution4--,in general1 it is advisable to begin the work of separating vegetable proteids by extracting the sample with a dilute brine usually of ten per cent strength4 ,as conducted by ,osborne and ,voorhees1 on wheat flour1 the manipulation is carried on as follows3#cgj ,the fine-ground whole wheat flour1 about four kilograms1 is shaken with twice that weight of a ten per cent sodium chlorid solution1 strained through a sieve1 to break up lumps1 and allowed to settle for sixteen hours4 ,at the end of this time1 about half of the supernatant liquid is removed by a siphon or by decantation and filtered4 ,two liters more of the salt solution are added1 the mixture well stirred and the whole brought onto the filter used above4 ,the filtrate is collected in successive convenient portions and each portion1 as soon as it is obtained1 is saturated with ammonium sulfate4 ,all the proteid matter is precipitated by this reagent4 ,the precipitate is collected on a filter1 redissolved in a convenient quantity of the salt solution and dialyzed for fourteen days or until all sulfates and chlorids are removed4 ,the proteid matter1 which is separated on dialysis1 in this instance1 is a globulin4 ,the proteid matter not precipitated on dialysis is assumed to be that part of the original substance soluble in water4 ,a part of the water soluble proteid matter obtained as above is coagulated by heat at from #ej to #hj4 ,the part not separated by heat gives a precipitate on saturation with sodium chlorid4 ,in wheat there are found soluble in water two albumins and a proteose4#cga ,in separating the albumin coagulating at a low boiling point from the dialyzed solution mentioned above1 it is heated to #fj for an hour1 the precipitate collected on a gooch1 washed with hot water 7#fj71 and then successively with ninety-five per cent alcohol1 water-free alcohol and ether4 ,on drying the residual voluminous matter on the filter over sulfuric acid1 it becomes dense and horny1 having in an ash free state1 according to ,osborne1 the following composition3 ,per cent4 ,carbon #ec4jf ,hydrogen #f4hb ,nitrogen #ag4ja ,sulfur #a4cj ,oxygen #ba4ha #cih4 ,treatment without ,precipitation with ,ammonium ,sulfate4--,where abundant means are at hand for dialyzing large volumes of solution1 the preliminary treatment of the solution made with ten per cent sodium chlorid with ammonium sulfate may be omitted4 ,when the precipitated proteids are to be used for the estimation of the nitrogen therein contained1 it has been proposed to substitute the corresponding zinc salt for the ammonium sulfate4#cgb ,this reagent has given satisfactory results in this laboratory and while a larger experience is desirable before commending it as an acceptable substitute in all cases1 yet its obvious advantage1 in being free of nitrogen for the use mentioned1 entitles it to careful consideration4 ,the manipulation1 with the exception of the precipitation with ammonium sulfate1 is the same as that described in the preceding paragraph4 ,the globulins are completely precipitated when the dialysis is complete and may be separated from the soluble albumins and proteoses by filtration4 #cii4 ,separation of the ,bodies ,soluble in ,water4--,albumins4--,by the methods of treatment just described1 the proteid matters soluble in ten per cent sodium chlorid solution are separated into two classes1 viz41 globulins insoluble in pure water and albumins and proteoses soluble in pure water4 ,the aqueous solution will also contain any amids or nitrogenous bases soluble in the dilute saline solution and in water4 ,osborne and ,voorhees have found that the best way of separating the albumins in the pure aqueous solution is by the application of heat4#cgc ,by means of a fractional coagulation the albumins are divided into classes1 viz41 those separating at from #fj to #fe and those remaining in solution at that temperature but separating up to #he4 ,the respective quantities of these albumins are determined by collecting them in a filter and estimating the nitrogen therein by moist combustion in the usual way4 ,even a larger number of albumins may be secured1 as in the maize kernel1 by such a fractional precipitation by means of heat4 ,chittenden and ,osborne find in this instance that the precipitation begins at about #dj4cgd ,proteose4--,after the separation of the albumins by heat the filtrate may still contain proteid matter4 ,this matter belongs to the proteose class4 ,it may be partially secured by concentrating the filtrate1 after the removal of the albumins1 to a small bulk when a part of the proteose body will separate4 ,it may be thrown out entirely by treating the filtrate above mentioned with fine-ground salt until it is saturated or by adding salt until the solution contains about twenty per cent thereof and precipitating the proteose by acetic acid4#cge #djj4 ,separation of the ,globulins4--,the globulins which are extracted with ten per cent solution of sodium chlorid and precipitated on dialysis may be separated by fractional solution into several bodies of nearly related properties4 ,this solution is conveniently accomplished by saline solvents of increasing strength4 ,in the case of the maize globulins1 ,chittenden and ,osborne employ dilute solutions of common salt for effecting the separation1 beginning with a quarter of a per cent and ending with a two per cent mixture4#cgf #dja4 ,proteids ,soluble in ,dilute ,alcohol4--,some of the proteid bodies which are soluble in dilute salt solution and in water are also soluble in alcohol4 ,since these bodies are more easily identified by the processes already described1 attention will be given in this paragraph solely to those proteid bodies which are insoluble in water or dilute salt solution and are soluble in dilute alcohol4 ,for the extraction of these bodies1 the residue1 left after extraction with a ten per cent solution of sodium chlorid or with water1 is mixed with enough strong alcohol to secure by the admixture with the water present in the sample an alcohol of about seventy-five per cent strength4 ,the mixture is well shaken and digested for some time1 at a temperature of about #df1 and thrown on a filter which is kept at about the same temperature4 ,the residue is again mixed with alcohol of the same strength 7seventy-five per cent7 using about four liters for two and a half kilos of the original material4 ,during the second digestion the temperature is kept at about #fj4 ,the latter operation is repeated three times and in each case the filtrate obtained is evaporated separately4#cgg ,this process is especially applicable to the meal from maize kernels1 which contains a high relative percentage of an alcohol soluble proteid1 zein4 ,the chief part of the zein is found in the first two extracts1 obtained as described above4 ,on evaporation1 the zein separates as a tough1 leathery1 yellow-colored mass on the walls of the containing vessel4 ,it is cut into small pieces and digested for several days in cold1 pure alcohol4 ,this is followed by digestion with a mixture of ether and pure alcohol1 and finally with pure ether4 ,by this treatment a part of the zein becomes insoluble in seventy-five per cent alcohol4 ,the part soluble in dilute alcohol is precipitated by pouring it into water4 ,another method of preparing zein is to extract the meal with seventy-five per cent alcohol after it has been treated with a ten per cent salt solution4 ,in this case the extraction is continued with seventy-five per cent alcohol in successive portions until no more proteid matter passes into solution4 ,the several extracts are united and the alcohol removed by distillation1 by which process the zein is separated4 ,it is washed with distilled water1 until the sodium chlorid is removed1 dissolved in warm alcohol of about eighty per cent strength and any insoluble matter removed by filtration4 ,on evaporating the filtrate nearly to dryness1 the zein is separated and pressed as free of water as possible1 yielding a yellow1 elastic substance resembling molasses candy4 ,this preparation is purified by digestion with pure alcohol and ether in the manner described4 ,the two zeins which are secured by the treatment1 one soluble and the other insoluble in alcohol1 are practically identical in composition4#cgh ,zein freshly precipitated by pouring its alcoholic solution in water is wholly insoluble in water1 and1 on boiling therewith1 is changed into the variety insoluble in dilute alcohol4 ,boiled with dilute sulfuric acid1 six in #cjj cubic centimeters of water1 it melts1 forming a gummy mass1 which is very slowly attacked by the acid yielding proteoses and peptones4 ,heated with stronger sulfuric acid it undergoes decomposition1 yielding leucin1 tyrosin1 and glutamic acid4 #djb4 ,solvent ,action of ,acids and ,alkalies4--,in the preceding paragraphs1 a synopsis has been given of the methods of separating proteid matters in such a manner as to secure them in a pure state in the same conditions as they exist in the natural substances4 ,a very large percentage of the proteid matter is still left undissolved after extraction with the solvents already mentioned4 ,often important information may be gained concerning the nature of the residual proteid matters by fractional extraction with dilute acids and alkalies4 ,when the strength of these solutions is such that they contain about one per cent of the acid or alkali1 the whole of the proteid matter may be dissolved by boiling successively with acid and alkali for half an hour4 ,the proteid matter passing into solution in these cases is usually changed in character1 assuming the nature of proteoses or allied bodies1 when treated with an acid1 and becoming albuminates when boiled with an alkali4 ,easily soluble carbohydrate matter is also removed by this treatment so that the residue obtained consists largely of cellulose and is known as crude or insoluble fiber4 ,the removal of all the bodies soluble in dilute boiling acid and alkali is accomplished by the method described in paragraph #bgb4 ,for research purposes1 the solvent action of dilute alkali is of chief importance to the analyst1 and the extraction of the proteid matter1 after all that is soluble in water1 common salt solution and alcohol has been removed1 should commence with a solution of potassium or sodium hydroxid containing not over two-tenths per cent of the alkali4 ,it has been shown by ,osborne that the solvent action of very dilute alkali1 in the cold1 may be exerted without changing the character of the dissolved proteid4#cgi #djc4 ,method of ,extraction4--,the solvent employed is usually a two-tenths per cent solution of potassium hydroxid4 ,it may be added directly to the substance or may follow extraction with water1 salt solution or alcohol4 ,in the former case1 the manipulation is illustrated by the following description of the treatment of oatmeal3#chj ,one hundred grams of oatmeal are mixed with half a liter of a two-tenths per cent potassium hydroxid solution and allowed to stand for some time at room temperature4 ,the mixture is strained through a cloth to remove the chaff and the residue is stirred with another small portion of the solvent1 again strained in the same cloth and the residue squeezed dry4 ,the strained liquids are united and enough more of the solvent added to make the volume #gjj cubic centimeters4 ,after standing for some time1 the insoluble matter settles to the bottom of the vessel and the supernatant liquid is decanted4 ,more solvent is added to the residue1 well mixed therewith and treated as above4 ,it is advisable to make a third extraction in the same way4 ,the extracts are united1 passed through a filter1 the proteid matter in solution thrown out by acetic acid1 washed with water1 alcohol and ether and dried over sulfuric acid4 ,the methods of procedure1 when the sample has been previously extracted with water1 salt solution or alcohol1 are essentially the same as that just described and the reader may consult the paper of ,osborne for details4#cha #djd4 ,methods of ,drying ,separated ,proteids4--,in the preceding paragraphs1 the analyst has been directed1 in most instances1 to dry the proteid matter1 after it is secured in as pure a form as possible1 at room temperature1 over sulfuric acid4 ,by this treatment the preparation may be obtained in a form suited to the study of its physical properties1 since its solubility has not been affected by subjecting it to a high temperature4 ,when it is desired to use the sample only for chemical analysis it is not necessary to wait on the slow process above mentioned4 ,in this case the sample may be dried in an inert atmosphere at the temperature of a steam-bath or even at #aaj4 ,it is better1 however1 to avoid so high a temperature and to conduct the desiccation in vacuo at a heat not above that of boiling water4 ,the sample1 before drying1 should be reduced to the finest possible state of comminution1 otherwise particles of aqueous vapor may be retained with great tenacity4 ,in many cases it is advisable to dry the sample pretty thoroughly1 then grind to a fine powder and finish the desiccation with the pulverulent mass4 ,this treatment can be followed when the quantity of the material is considerably in excess of that required for the analytical operations4 #dje4 ,determination of ,ash4--,no method of treatment is known by means of which vegetable proteid matters may be obtained entirely free of mineral matters4 ,the mineral bases may be naturally present in the proteid matter as organic and inorganic salts1 or they may be mechanically entangled therewith1 having been derived either from the other tissues of the plant or from the solvents employed4 ,it is necessary in calculating the analytical data to base the computation on the ash free substance4 ,the percentage of ash is determined by any of the standard processes or by heating the sample in a combustion tube1 to very low redness1 in a current of oxygen4 ,the total residue obtained is used in calculating the percentage of ash1 and the weights of material subsequently used for the determination of carbon1 hydrogen1 nitrogen and sulfur are corrected for the calculations by deducting the quantity of mineral matter contained therein4 ,by reason of the highly hygroscopic nature of the dry proteid bodies1 they must be kept over a desiccating material and weighed quickly on a balance1 in an atmosphere which is kept free of moisture by the usual methods4 #djf4 ,carbon and ,hydrogen4--,carbon and hydrogen are estimated in proteid matters by combustion with copper oxid4 ,osborne prefers to burn the sample in a platinum boat in a current of air or of oxygen free of moisture and carbon dioxid4#chb ,it is advisable to use also a layer of lead chromate in addition to the copper oxid and metallic copper4 ,the method of conducting the combustion has already been described4#chc ,the analyst should have at his disposal a quantity of pure sugar1 which may be used from time to time in testing the accuracy of the work4 ,in beginning a series of combustions this precaution should never be omitted4 ,the addition of the lead chromate is to make more certain the absorption of oxidized sulfur produced during the combustion4 #djg4 ,estimation of ,nitrogen4--,in most cases it is found convenient1 during the progress of separating vegetable proteids1 to determine the quantity of each kind by estimating the nitrogen by moist combustion and computing the quantity of proteid matter by multiplying the nitrogen by #f4be4 ,the estimation of the nitrogen is made either on an aliquot part of the extract or by direct treatment of the residue4 ,in the pure extracted proteid matter the nitrogen is most conveniently determined by moist combustion1 but it may also be obtained either by combustion with soda-lime or with copper oxid1 or by other reliable methods4#chd ,the percentages of nitrogen found in the principal proteid bodies1 together with the factors for computing the weights of the proteid bodies from the weights of nitrogen found1 are given below3 ,name of body4 ,percentage of nitrogen4 ,factor4 ,mucin #ac4hj to #ad4ac #g4be to #g4jh ,chondrin #ad4bj to #ad4fe #g4jd to #f4hc ,albuminates #ac4hg #g4ba ,oat proteids #ae4he #f4ca ,serum globulin #ae4fc #f4dj ,egg albumin #ae4ga to #ag4he #f4cg to #e4fj ,maize proteids #af4jf #f4bb ,casein #ae4da to #af4bi #f4di to #f4ac ,serum albumin #ae4if #f4bg ,syntonin #af4aj #f4ba ,keratin #af4bj to #ag4gj #f4ag to #e4fe ,fibrinogen #af4fe #f4ja ,peptones #af4ff to #ag4ac #f4jj to #e4hd ,elastin #af4ge #e4ig ,wheat proteids #af4hj to #ah4ci #e4ie to #e4dd ,fibrin #af4ia #e4ia ,flax seed proteids #ag4gj to #ah4gh #e4fe to #e4cc #djh4 ,determination of ,sulfur4--,sulfur is a characteristic constituent of the proteid bodies1 existing in quantities approximating one per cent of their weight4 ,in the estimation of sulfur1 it is first converted into sulfuric acid1 which is thrown out by a soluble barium salt and the sulfur finally weighed as barium sulfate4 ,all the sulfur existing in the organic state in a proteid may be obtained by burning in a current of oxygen and conducting the gaseous products of combustion through solid sodium or potassium carbonate at or near a red heat4#che ,the organic sulfur may also be converted into sulfuric acid by fusing the proteid body with a mixture of sodium hydroxid and potassium nitrate4 ,the fused mass1 after cooling1 is dissolved in water1 the solution acidified with hydrochloric1 evaporated to dryness to decompose nitrates and remove excess of hydrochloric acid and dissolved in a large excess of water4 ,after standing for a day1 the solution is filtered and the sulfuric acid thrown out of the hot filtrate with a slight excess of barium chlorid solution4 ,the usual precautions in precipitating1 filtering and igniting the barium sulfate are to be observed4#chf #dji4 ,general ,observations4--,in the preceding paragraphs have been stated the general principles upon which the separation of vegetable proteid matters depends1 and a description has been given of the several processes by which this separation is accomplished4 ,in each case1 however1 special conditions exist which require special modifications of the general processes1 and these can only be successfully secured by the skill1 judgment and patient labor of the investigator4 ,many of these cases have been already worked out1 and the valuable data secured by ,chittenden1 ,osborne and others1 are accessible to the analyst in the papers already cited4 ,in the case of the proteids in the peanut1 a similar work has been done in this laboratory by ,bigelow1 the data of which have not yet been published4 ,it is only by a careful study of the work already done as outlined here and as published in full in the cited papers1 that the analyst will be able to secure trustworthy guidance for future investigations4 #daj4 ,dialysis4--,one of the most important of the operations connected with the separation and analysis of proteids is the removal of the salts whereby their solutions are secured4 ,this is accomplished by subjecting the solutions of the proteid matters to dialysis4 ,the solution is placed in bags made of parchment dialysis paper4 ,these bags are tied about a glass tube1 whereby access may be had to their contents during the progress of the work4 ,since the volume of the liquid increases during the process1 the bags should not be filled too full in the beginning4 ,illustration3 ,,fig4 #aje4 ,,dialyzing ,,apparatus4 ,in this laboratory the dialysis is carried out by ,bigelow with the city water from the ,potomac1 which is first passed through a battery of porous porcelain filtering tubes to remove any suspended silt or micro-organisms4 ,if unfiltered water be used1 the germs therein cause a fermentation in the proteid matter1 which seriously interferes with the value of the data obtained1 and which can only be avoided by the use of an antiseptic1 such as an alcoholic solution of thymol4 ,even with filtered water1 the use of a few drops of the solution mentioned is often necessary4 ,to avoid the use of too great quantities of the filtered water1 the dialyzers are arranged en batterie1 as shown in the figure4 ,the filtered water enters the first vessel and thence passes through all4 ,the parchment bags are frequently changed from vessel to vessel1 each being brought successively into the first vessel in contact with the fresh water4 ,in some cases the final steps in the dialysis may be accomplished in distilled water4 ,it is advisable to conduct a fractional preliminary dialysis of the salt solution containing proteids in such a way as to secure the globulins precipitated in each interval of twenty-four hours4 ,each portion thus secured may be examined with the microscope4 ,usually a period of two weeks is required to entirely remove the mineral salts from solution4 ,if prepared parchment tubes be used for the dialysis1 they should be first tested for leaks1 and should not be more than half filled4 ,by the use of a large number of these tubes a greater surface is exposed to dialytic action1 and the time required to complete the operation is correspondingly decreased4 ,,separation ,,and ,,estimation ,,of ,,nitrogenous ,,bodies ,,in ,,animal ,,products4 #daa4 ,preparation of the ,sample4--,animal products present many difficulties in respect of the reduction thereof to a sufficiently comminuted condition for analytical examination4 ,in the case of bones1 the choppers used for preparing them for feeding to fowls are the most efficient apparatus for reducing them to fragments4 ,in this condition they may be ground to a finer state in a sausage machine4 ,the flesh of animals may be reduced by this machine1 with two or three grindings1 to a fairly homogeneous mass4 ,subsequent grinding in a mortar with powdered glass or sharp sand may serve to reduce the sample to a finer pulp1 but is not usually necessary and should be avoided when possible4 ,the sample thus prepared serves for the estimation of water1 ash and fat by methods already described4 ,the sample should be prepared in quantities of considerable magnitude1 the whole of any organ or separate portion of the body being used when possible4 ,in examining the whole body the relative weights of blood1 bones1 viscera1 muscle1 hide and other parts should first of all be ascertained and noted4 #dab4 ,treatment of ,muscular ,tissues for ,nitrogenous ,bodies4--,for the present purpose a brief sketch of the method of separating the nitrogenous bodies in the muscular tissues of the body is all that can be attempted4 ,for methods of examining the different organs and parts of the body in greater detail1 standard works on physiological chemistry may be consulted4#chg ,extraction with ,cold ,water4--,a noted quantity of the finely divided tissues is mixed with several volumes of ice-cold water and well rubbed occasionally for several hours1 the temperature meanwhile being kept low4 ,the mixture is poured into a linen bag and the liquid portion removed by gentle pressure4 ,the residue in like manner is treated with fresh portions of cold water until it gives up no further soluble matters4 ,an aliquot portion of the extract is concentrated to a small bulk and serves for the determination of total nitrogen4 ,the methods of separating and estimating nitrogenous bodies in flesh soluble in water will be given in considerable detail further on4 ,extraction with ,ammonium ,chlorid and ,hydrochloric ,acid4--,the residue1 after exhaustion with cold water1 is extracted with a solution of ammonium chlorid containing #aej grams of the salt in a liter4 ,this method of extraction is entirely similar to that with water just described4 ,globulins and myosin pass into solution by this treatment4 ,the residual mass is washed as free as possible of the solvent and is then further extracted with dilute hydrochloric acid containing four cubic centimeters of the fuming acid in a liter4 ,the treatment with dilute acid is continued until no further substance passes into solution4 ,this is determined by neutralizing a portion of the extract with sodium carbonate1 or by the direct addition of potassium ferrocyanid4 ,in either case absence of a precipitate indicates that no nitrogenous matters are present in the solution4 ,extraction with ,alkali4--,the residue from the acid extraction is washed with water until the acid is removed and then extracted in a similar manner with a dilute solution of sodium or potassium hydroxid containing not to exceed two grams of the caustic to the liter4 ,when this residue is finally washed with water and a little acetic acid1 it will be found that practically all the purely albuminous bodies contained in the tissues have been extracted with the exception of any fibrin1 which the blood1 present in the tissues at the commencement of the extraction1 may have contained4 ,the extract should be acidified with acetic as soon as obtained4 ,extraction with ,boiling ,water4--,the residual matter boiled for some time with water will part with its collagen1 which1 when transformed by the heat into glutin1 passes into solution4 ,the sarcolemma1 membranes1 elastic fibers and keratin remain undissolved4 #dac4 ,contents of the ,several ,extracts4--,by the systematic treatment of muscular tissues in the manner just described1 the nitrogenous bodies they contain are separated into five classes1 viz43 ,cold ,water ,extract4--,this contains serum albumin1 serum globulin1 muscle albumin1 myosin1 mucin and peptone4 ,ammonium ,chlorid ,extract4--,this solution contains the globulins and also in many cases some myosin and serum globulin4 ,hydrochloric ,acid ,extract4--,when the extractive matter removed by hydrochloric acid1 thrown out by sodium carbonate and well washed with water1 has a neutral reaction1 it consists of syntonin1 when acid1 of an albuminate4 ,alkali ,extract4--,the acid albumin of the animal tissue is found in the alkaline solution and may be thrown out by making the solution slightly acid4 ,insoluble ,residue4--,the fifth class contains the insoluble nitrogenous bodies mentioned above4 #dad4 ,general ,observations4--,only a brief rsum of the methods of treating animal tissues for nitrogenous bases is given above1 since a more elaborate discussion of these principles and methods would lead too far away from the main purpose of this manual4 ,for practical purposes1 the most important of these bodies are those soluble in water and the methods of treating these will be handled at some length4 ,unfortunately1 the methods of determining the exact qualities of these bodies are not as satisfactory in case of animal as in vegetable nitrogenous bodies4 ,the flesh bases1 soluble in water1 contain a much larger percentage of nitrogen than is found in true proteid bodies1 and therefore the multiplication of the weight of nitrogen found therein by #f4be does not give even a near approximation of the actual quantities of the nitrogenous bodies present in the sample4 ,some of the flesh bases contain more than twice as much nitrogen as is found in proteids1 and in such cases #c4ab1 and not #f4be1 would be the more correct factor to use in the computation4 ,when possible1 therefore1 these bodies should be precipitated and weighed after drying1 but this is not practicable in many instances4 ,the sole resource of the chemist in such cases is to determine the nature of the body as nearly as possible by qualitive reactions1 then to determine the total nitrogen therein and multiply its weight by the corresponding factor4 ,the principal flesh bases have the following percentages of nitrogen and the approximate factors for calculating analytical data are also given3 ,name of base4 ,formula4 ,per cent ,factor4 nitrogen4 ,glutin ,c,h,n,o #ag4ie #e4eg ,carnin ,c,h,n,o #ca4aa #c4ba ,kreatin ,c,h,n,o #cb4jf #c4ab ,kreatinin ,c,h,n,o #cg4ag #b4fi ,sarkin ,c,h,n,o #da4ah #b4dc #dae4 ,composition of ,meat ,extracts4--,the meat extracts of commerce contain all the constituents of meat that are soluble in warm water4 ,the parts which are soluble in warm water and not in cold are found in the cold aqueous solution as suspended or sedimentary matters4 ,among the nitrogenous bodies present are included albumin1 albumose and peptone among the proteids1 carnin1 kreatin1 kreatinin1 sarkin and xanthin among the non-proteids1 and inosinic and uric acids and urea among other nitrogenous bodies4 ,among the non-nitrogenous bodies are found lactic and butyric acids1 inosit and glycogen4 ,among mineral bodies occurs the phosphates and chlorids of the common bases4 ,in addition to these bodies1 meat extracts may also contain gelatin and other decomposition products of proteid matter4 ,since meat extract is supposed to be prepared by the digestion of the meat free of bones and put in cold water or in warm water not above #ge1 the presence of gelatin would indicate a different method of preparation1 viz41 either by boiling water or water heated above the boiling point under pressure4 ,in a properly prepared extract1 the percentage of gelatin is very small4 ,approximately one-tenth of the whole nitrogen present is in the form of albumoses and only a trace as peptones4 ,by far the greater part of the nitrogen exists as flesh bases 7kreatin1 etc474 ,the composition of three meat extracts1 numbers one and two solid and number three liquid1 is given in the subjoined table4#chh ,no4 #a4 ,no4 #b4 ,no4 #c4 ,per cent4 ,per cent4 ,per cent4 ,total nitrogen #i4bh #i4ad #b4gg ,nitrogen as albumin trace #j4jh trace 0 0 albumose #j4if #a4ba #j4gj 0 0 peptone trace trace none 0 0 flesh bases #f4ha #e4ig #a4ef 0 0 ammonia #j4dg #j4da #j4ji 0 in compounds insoluble in sixty-six per cent alcohol #j4ba #j4cc #j4be 0 0 other bodies #j4hc #a4ad #j4ag #dag4 ,analysis of ,meat ,extracts4--,the analysis of a meat extract should include the determination of the water1 ash and total nitrogen4 ,after multiplying the nitrogen which exists as proteids by #f4be and adding together the percentages of all the ingredients1 ash1 water1 etc41 including ammonia1 the sum is to be subtracted from #ajj and the difference entered as non-nitrogenous organic matter4 ,the nature of this conglomerate has already been explained4 ,water4--,it is advisable to determine the water in a partial vacuum 7#bj7 or in an atmosphere of hydrogen 7#bc-be74 ,the water may also be determined in solid extracts by placing about five grams of the material in a flat bottom tin foil dish about fifty-five millimeters in diameter and twenty millimeters deep4 ,the material is dissolved in enough warm water to fill the dish a little over one-half and the liquid is then absorbed by adding a weighed quantity of fibrous asbestos or of dry fragments of pumice stone4 ,the asbestos is to be preferred because of the fact that it may be subsequently cut into small bits for the determination of the gelatin4 ,the dish thus prepared is dried to constant weight in a steam-bath or vacuum oven4 ,the weight of the dish and of the added absorbent1 together with that of the material employed and of the dried dish and its contents1 give the data for calculating the percentage of water4 ,the contents of the dish are used as described further on for the determination of gelatin4 ,in liquid extracts the water is determined in an entirely analogous manner1 using about twenty grams of the material and omitting the solution in water4 ,in solid extracts1 the part insoluble in cold water is determined separately4 ,ash4--,the ash is determined by ignition at the lowest possible temperature1 best in a muffle 7#bh-cb74 ,the ash should be examined qualitively4 ,where a quantitive analysis is desired1 larger quantities of the extract are incinerated and the constituents of the ash determined in the usual way4#chi ,total ,nitrogen4--,since nitrates are not present unless added in the manufacture1 the total nitrogen is best determined by moist combustion4#cij ,nitric ,nitrogen4--,the extract should be tested for nitrates and if present they are determined in the manner already described4#cia ,ammoniacal ,nitrogen4--,when ammonia is present it is determined by distillation with magnesia4#cib ,since boiling with magnesia may cause the distillation of more ammonia than is present as ammonium salts1 the plus being due to the decomposition of some other nitrogenous compounds1 ,stutzer replaces the magnesia with barium carbonate4#cic ,proteid ,nitrogen ,insoluble in ,sixty-,two ,per ,cent ,alcohol4--,the aqueous solution is treated with strong alcohol until the mixture contains about sixty-two per cent of the reagent4 ,the precipitate produced is separated by filtration1 washed with sixty-two per cent alcohol and the nitrogen therein determined4 ,albumose ,nitrogen4--,this is secured by saturating the aqueous solution with zinc or ammonium sulfate4 ,the separated albumoses are skimmed from the surface1 thrown in a filter1 washed with a saturated solution of zinc sulfate and the nitrogen determined therein by moist combustion4 ,in the filtrate from the above separation1 peptone is detected qualitively by adding a few drops of dilute solution of copper sulfate 7biuret reaction74 ,kreatin1 ,kreatinin and ,other ,flesh ,bases4--,the clear1 aqueous solution of the extract is acidified with sulfuric1 mixed with a solution of sodium phosphotungstate and allowed to stand for about six days4 ,the precipitate is collected1 washed with a solution of the precipitant1 and the nitrogen therein determined4 ,the nitrogen found1 less that due to ammonia1 represents the total nitrogenous matter precipitated by the phosphotungstic acid4 ,from this quantity is deducted the nitrogen in the proteids1 precipitated by sixty-two per cent alcohol and by ammonium or zinc sulfate1 and the remainder represents the nitrogen in flesh bases4 ,the nitrogen thrown out by the phosphotungstic acid is deducted from the total nitrogen1 and the remainder represents the nitrogenous bodies not precipitable by the reagent named4 ,this method of separating the nitrogenous matters in meat extracts is based on the observation that these bodies contain at most only a small quantity of peptones1 so small as to be safely negligible4#cid ,quantities used for ,analysis4--,in conducting the separations above noted1 it will be found convenient to use in each case about five grams of the solid or twenty of the liquid extract4 ,in the nitrogen determinations1 the weight of the sample should be inversely proportional to its content of nitrogen4 #dag4 ,preparation of the ,phosphotungstic ,reagent4--,the phosphotungstic reagent is conveniently prepared as follows3 ,dissolve #abj grams of sodium phosphate and #bjj of sodium tungstate in one liter of water and add to the solution #ajj cubic centimeters of strong sulfuric acid4 ,when the reagent is prepared for general purposes it is customary to acidify with nitric1 but in the present instance1 inasmuch as the precipitate is used for the determination of nitrogen1 it is evident that sulfuric should be substituted for nitric acid4 ,in all cases the analyst must be assured of the strong acidity of the reagent1 and in addition to this the solutions of proteid matter to which the reagent is added must first be made strongly acid with sulfuric4 #dah4 ,zinc ,sulfate as ,reagent for ,separating ,albumoses from ,peptones4--,when the albumoses are separated from the peptones1 by precipitation with ammonium sulfate1 there may be danger of some of this reagent adhering to the albumose1 and in this way the quantity of nitrogen obtained on analysis may be increased4 ,to avoid an accident of this kind ,bmer replaces the ammonium by zinc sulfate4#cie ,since the precipitation of the albumoses by saturated saline solutions depends on their hydrolytic power1 the substitution of another salt for ammonium sulfate capable of strongly attracting water1 may be made if that salt does not possess any objectionable property4 ,crystallized zinc sulfate will dissolve in less than its own weight of cold water and is therefore well suited for the purpose in view4 ,in the case of a meat extract1 the precipitation is accomplished as follows3 ,fifty cubic centimeters of the extract1 freed from all solid matter by filtration and containing about two grams of the soluble proteids1 are saturated in the cold with finely powdered zinc sulfate4 ,the separated albumoses collect on the surface and are skimmed off1 poured on a filter and washed with cold saturated zinc sulfate solution4 ,the filter and its contents are used for the determination of nitrogen by moist combustion4#cif ,the filtrate from the precipitated albumoses gives no biuret reaction1 and1 therefore1 as in the use of ammonium sulfate1 is free of albumin4 ,the biuret reaction is applied to the zinc sulfate filtrate as follows3 ,the filtrate is greatly diluted with water and freed of zinc by means of a saturated solution of sodium carbonate4 ,the filtrate free of zinc is evaporated on the steam-bath1 made strongly alkaline with sodium hydroxid and treated with a few drops of a two per cent copper sulfate solution1 added successively4 ,another advantage possessed by the zinc sulfate is found in the fact that in the filtrate from the separated albumoses the peptones and other flesh bases can be thrown out by phosphotungstic acid4 ,before the application of the reagent1 the filtrate should be made strongly acid by adding about an equal volume of dilute sulfuric acid 7one part of acid to four of water47 ,the nitrogen in the precipitate thus obtained is determined by moist combustion in the manner already suggested4 ,if the proteid matters contain salts of ammonium it is probable that a difficultly soluble double sulfate of zinc and ammonium1 7,,nh7,,so4,zn,s,o4#f;,h,o1 will be found in the precipitate4 ,ammonium salts1 if present1 should therefore be removed by distillation with magnesia4 ,it is better1 however1 to throw down the ammonia with the first zinc precipitate1 distil this with magnesia and determine the amount of nitrogen derived from the ammonia compounds4 ,in a second sample1 the total nitrogen is determined by moist combustion and the difference between the two results gives that due to albumoses4 #dai4 ,examination for ,muscular ,tissue4--,some samples of meat extracts contain small quantities of finely ground muscular tissue4 ,for detecting this the extract is treated with cold water and the insoluble residue examined with a microscope4 ,if muscular tissue be found1 about eight grams of the extract or twenty-five of the fluid preparation1 are treated with cold water1 the insoluble matter collected upon a filter1 washed with cold water1 and the nitrogen determined in the residue4 ,the percentage of nitrogen multiplied by #f4be gives the quantity of muscle fiber proteids present4 ,the filtrate from the above determination is acidified with acetic1 boiled1 any precipitate which is formed collected and the nitrogen therein determined4 ,the nitrogen obtained multiplied by #f4be gives the quantity of coagulable albumin present4 ,an aliquot portion of the filtrate is used for the determination of nitrogen and the percentage therein found1 deducted from the total nitrogen of the sample1 gives a remainder which may be used as a representative of the whole of the nitrogen present in the form of albumin and muscular tissue4 #dbj4 ,estimation of ,gelatin4--,the tin foil dish and its contents used for the determination of water1 as above described1 are cut into small pieces1 placed in a beaker and extracted four times with absolute alcohol4 ,after the removal of the alcohol1 the residue is extracted with ice water containing ten per cent of alcohol1 in which a small piece of ice is kept to avoid a rise of temperature4 ,the beaker should be shaken during the extraction1 which should last for about two minutes4 ,where large numbers of samples are treated at once1 any convenient form of shaking machine may be employed4 ,at least two extractions with ice water must be made4 ,the residue is then collected upon a filter and washed with ice water until the washings are completely colorless4 ,the residue on the filter is replaced in the beaker1 boiled with water1 well washed on the filter with boiling water1 the filtrate and washings concentrated and the nitrogen therein determined4 ,the principle of this determination is based on the fact that gelatin is almost completely insoluble in ice water while serum peptones and albumin peptones are almost completely soluble in that reagent4 ,on the other hand1 the flesh bases and the proteids present are almost completely removed by the preliminary treatment with alcohol and ice water or are left undissolved by the hot water4 ,the solution in boiling water1 therefore1 contains practically nothing but gelatin4#cig ,in a later article1 ,stutzer modifies the method given above as follows3#cih ,of dry and moist extracts from five to seven grams and of liquid extracts from twenty to twenty-five grams are used for the determination and placed in tin foil dishes1 as described above4 ,in case of solid extracts1 a sufficient quantity of warm water is added to completely dissolve them1 the solution being facilitated by stirring4 ,in case the solution is too thin it should be concentrated before going further4 ,it is treated with a sufficient amount of dust-free ignited sand to completely absorb it1 and the dish and its contents are then dried to a constant weight4 ,the dried contents of the dish are rubbed up in a mortar1 the dish cut into fine bits1 and all placed in a beaker4 ,the solid syrphete#cii is extracted four times with #ajj cubic centimeters of absolute alcohol1 the alcohol in each case being poured through an asbestos filter for the purpose of collecting any matters suspended therein4 ,in a large flask are placed #ajj grams of alcohol1 #cjj grams of ice and #fjj grams of cold water1 and the flask is placed in a large vessel and packed with finely divided ice4 ,four beakers marked b1 c1 d1 e are also placed in ice and the beaker containing the syrphete1 left after extraction with absolute alcohol as above mentioned1 is marked a and also placed in pounded ice4 ,the extraction with cold alcoholic water proceeds as follows3 ,in beaker a are poured #ajj cubic centimeters of the mixture in the large flask1 its contents are stirred for two minutes and then the liquid portion poured off into beaker b to which1 at the same time1 a piece of ice is added4 ,in beaker a are poured again #ajj cubic centimeters from the large flask1 treated as above described1 and the liquid extract poured into beaker c4 ,in like manner the extraction in beaker a is continued until each of the beakers has received its portion of the extract4 ,by this time the liquid over the sand in beaker a should be completely colorless4 ,the filtration of the liquid extract is accomplished as follows3 ,in a funnel of about seven centimeters diameter is placed a perforated porcelain plate about four centimeters in diameter which is covered with asbestos felt with long fiber4 ,three filters are prepared in this way4 ,on the first filter are poured the contents of beaker b4 ,after the liquid has passed through1 the sand and other residue in beaker a are transferred to the filter and the beaker and residue washed with the alcoholic ice water from the large flask4 ,the filtration should be accomplished under pressure4 ,on the second filter are poured the contents of beaker c4 ,on the third filter the contents of beakers d and e4 ,the washing with alcoholic ice water from the large flask is continued in each instance until the filtrate is colorless4 ,at the same time the asbestos filter1 which was used in the first instance for filtering the absolute alcohol extract1 is washed with the alcoholic ice water mixture from the large flask4 ,at the end the sand remaining in beaker a together with all the asbestos filters are brought together into a porcelain dish1 boiled two or three times with water1 the aqueous solution filtered and the filtrate concentrated and used for the estimation of the nitrogen4 ,the quantity of nitrogen found multiplied by #f4be represents the proteid matter in the gelatin of the sample4 ,the object of the multiple filters1 described above1 is to accelerate the process1 and they are required because the gelatin quickly occludes the filter pores4 ,for this reason the asbestos filters are found to operate better than those made of paper4 ,it should be mentioned that the residue of the peptones insoluble in alcohol may contain1 in addition to gelatin1 also small quantities of albumoses4 ,from the quantity of albumose nitrogen found1 it is understood that the nitrogen in the form of coagulable albumin1 determined as described in the first process mentioned above1 is to be deducted1 since these coagulable albumins are insoluble in alcohol4 #dba4 ,estimation of ,nitrogen in the ,flesh ,bases ,soluble in ,alcohol4--,about five grams of the dry extract1 ten grams of the extract containing water or twenty-five grams of the liquid extract are placed in a beaker and enough water added in each case to make about twenty-five cubic centimeters in all4 ,usually no water need be added to the liquid extracts4 ,very thin peptone solutions should be evaporated until the content of water is reduced to seventy-five per cent4 ,the solution1 prepared as above indicated1 is treated slowly with constant stirring with #bej cubic centimeters of absolute alcohol1 the stirring continued for some minutes and the vessel set aside for twelve hours1 at the end of which time the precipitate is separated by filtration and washed repeatedly with strong alcohol4 ,leucin1 tyrosin and a part of the flesh bases are dissolved by alcohol4 ,the alcohol is removed by distillation and the residue dissolved in water4 ,any flocky residue which remains on solution with water is removed by filtration1 the nitrogen determined therein and the quantity thereof added to the albumose nitrogen found1 as hereafter described4 ,the volume of the aqueous solution is completed with water to half a liter4 ,one hundred cubic centimeters of this solution are used for the determination of total nitrogen1 and another #ajj cubic centimeters for the determination of ammoniacal nitrogen by distillation with barium carbonate4 ,a part of the ammonia may have escaped during the preliminary distillation of the alcohol and therefore the amount found may not represent the whole amount originally present4 ,the use of the above determination is principally to ascertain the correction to be made in the amount of total nitrogen found in the first #ajj cubic centimeters of the solution4 #dbb4 ,treatment of the ,residue ,insoluble in ,alcohol4--,the residue insoluble in alcohol is washed from the filter into the beaker in which the first solution was made4 ,the aqueous mixture is warmed on a water-bath until the alcohol adhering to the precipitate is completely evaporated1 when the contents of the beaker are poured upon a filter free of nitrogen4 ,a small part of the albumose1 by reason of the treatment with alcohol1 tends to remain undissolved1 and it is advisable to collect this albumose upon a filter1 wash it well with hot water and estimate the nitrogen therein4 ,the quantity of nitrogen thus found is to be added to the albumose nitrogen determined as described later on4 ,the total filtrate obtained from the last filtration is made up to a volume of half a liter1 of which fifty cubic centimeters are used for the determination of total nitrogen1 fifty cubic centimeters for the determination of gelatin1 albumose and peptone1 and #ajj cubic centimeters for the residual peptones4 ,the albumose1 together with the gelatin and peptones carried down with it1 is precipitated with zinc or ammonium sulfate solution1 and its per cent calculated from the amount of nitrogen found in the precipitate4 ,the true peptone is determined by subtracting the quantity of nitrogen determined as albumose from the total nitrogen in solution4 ,the rest of the liquid1 viz41 #cjj cubic centimeters1 is evaporated to a small volume and tested qualitively for true peptones as follows3 ,to separate the albumose and gelatin a concentrated liquor is treated with an excess of finely divided ammonium sulfate so that a part of the salt remains undissolved4 ,the separated albumose1 gelatin and undissolved ammonium salts are collected on a filter1 the filtrate mixed with a few drops of dilute copper sulfate solution and a considerable quantity of concentrated soda or potash lye added4 ,care should be taken that the quantity of copper is not too great1 otherwise the peculiar red coloration will be obscured by the blue color of the copper solution4 #dbc4 ,pancreas ,peptone4--,the filtrate obtained as described above1 by treating the portion of the material insoluble in alcohol with warm water1 contains in addition to the albumose and gelatin the whole of the pancreas peptone which may be present4 ,to separate this peptone1 #ajj cubic centimeters of the aqueous solution are evaporated in a porcelain dish until the volume does not exceed ten cubic centimeters4 ,when cool1 at least #ajj cubic centimeters of a saturated cooled solution of ammonium sulfate solution are added1 the mixture thoroughly stirred1 the precipitate collected upon a filter and washed with a cold saturated solution of ammonium sulfate4 ,the contents of the filter are dissolved in boiling water1 the filter thoroughly washed and the filtrate and washings evaporated in a porcelain dish with the addition of barium carbonate until1 on the addition of new quantities of barium carbonate1 no further trace of ammonia can be discovered4 ,the residue is extracted with water1 the barium sulfate and carbonate present separated by filtration1 well washed and the nitrogen determined in the evaporated filtrate and washings in the usual way and multiplied by #f4be to determine the quantity of pancreas peptone4 #dbd4 ,albumose ,peptone4--,a part of the albumose peptone which may be present is determined in conjunction with the other bodies mentioned above4 ,the chief quantity is found in the solution of the residue insoluble in alcohol in the following manner3 ,fifty cubic centimeters of the solution of this residue in hot water are mixed with an equal volume of dilute sulfuric acid1 one volume of acid to three of water1 in the cold1 and a solution of sodium phosphotungstate added until it produces no further precipitate4 ,the precipitate is washed with dilute sulfuric acid and the nitrogen determined therein4 ,the nitrogen thus found is derived from the albumose1 pancreas peptone and gelatin4 ,the quantity of nitrogen in the pancreas peptone and gelatin1 as above described1 is subtracted from the total quantity found in the phosphotungstic acid precipitated1 and the remainder represents the nitrogen due to the albumose4 #dbe4 ,nitrogen in the ,form of ,flesh ,bases ,insoluble in ,alcohol4--,this is determined by subtracting the quantity of nitrogen1 determined by the phosphotungstic acid method already described1 from the total quantity of nitrogen found in the precipitate insoluble in alcohol and soluble in water4 ,,authorities ,,cited ,,in ,,part ,,fifth4 #ccg ,watts' ,dictionary of ,chemistry1 new edition1 ,vol4 #d1 p4 #cbg4 #cch ,vid4 op4 cit4 supra1 p4 #ccj4 #cci ,barbieri1 ,journal fr praktische ,chemie1 neue ,folge ,band #ah1 ,s4 #aad4 #cdj ,vid4 op4 cit4 #a1 p4 #cci4 #cda ,bulletin ,no4 #di1 ,kansas ,experiment ,station1 ,may1 #ahie4 #cdb ,this work1 ,vol4 #b1 p4 #bjh4 #cdc ,vid4 op4 cit4 supra1 ,vol4 #a1 p4 #egj4 #cdd ,wiley1 ,american ,chemical ,journal1 ,vol4 #f1 ,no4 #e1 p4 #bhi4 #cde ,obermayer1 ,chemiker-,zeitung ,repertorium1 ,oct4 #ahhi1 ,s4 #bfi4 #cdf ,hoppe-,seyler1 ,handbuch der physiologisch- und pathologisch-chemischen ,analyse1 ,s4 #bfi4 #cdg ,wiley1 ,american ,chemical ,journal1 ,vol4 #f1 p4 #bhi4 #cdh ,dragendorff's ,plant ,analysis1 p4 #ee4 #cdi ,this work1 ,vol4 #b1 pp4 #aib et seq4 #cej ,chemiker-,zeitung1 ,band #bj1 ,s4 #aea4 #cea ,this work1 ,vol4 #b1 p4 #bjg4 #ceb ,landwirtschaftlichen ,versuchs-,stationen1 ,band #ag1 ,s4 #cba3 ,zeitschrift fr analytische ,chemie1 ,band #ad1 ,s4 #chj4 #cec ,vid4 op4 cit4 #ab1 p4 #bde4 #ced ,landwirtschaftlichen ,versuchs-,stationen1 ,band #af1 ,s4 #fa4 #cee ,berichte der deutschen chemischen ,gesellschaft1 ,band #aj1 ,ss4 #he1 #aii2 ,band #af1 ,s4 #cab3 ,chemiker-,zeitung1 ,band #bj1 ,s4 #ade4 #cef ,zeitschrift fr analytische ,chemie1 ,band #bb1 ,s4 #cbe4 #ceg ,richardson and ,crampton1 ,berichte der deutschen chemischen ,gesellschaft1 ,band #ai1 ,s4 #aahj4 #ceh ,maxwell1 ,american ,chemical ,journal1 ,vol4 #ac1 p4 #dgj4 #cei ,vid4 op4 cit4 supra1 ,vol4 #ae1 p4 #ahe4 #cfj ,vid4 op4 cit4 supra1 ,vol4 #ac1 p4 #ac3 ,schulze1 ,zeitschrift physiologische ,chemie1 ,band #ad1 ,s4 #dia4 #cfa ,this work1 ,vol4 ,i1 p4 #daa4 #cfb ,vid4 op4 cit41 #bb1 ,vol4 #ac1 p4 #ae4 #cfc ,vid4 op4 cit4 supra1 ,vol4 #ae1 p4 #ahh4 #cfd ,hoppe-,seyler1 ,handbuch der physiologisch- und pathologisch-chemischen ,analyse1 ,s4 #afi4 #cfe ,this work1 ,vol4 #b1 p4 #bbe4 #cff ,bulletin ,no4 #de1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #ea4 #cfg ,osborne and ,voorhees1 ,american ,chemical ,journal1 ,vol4 #ae1 p4 #dgj4 #cfh ,vid4 op4 cit4 supra1 ,vol4 #ac1 p4 #che4 #cfi ,vid4 op4 cit4 supra1 p4 #dab4 #cgj ,vid4 op4 cit4 supra1 ,vol4 #ae1 p4 #djb4 #cga ,vid4 op4 cit4 supra1 p4 #djd4 #cgb ,zeitschrift fr analytische ,chemie1 ,band #cd1 ,s4 #efb4 #cgc ,vid4 op4 cit4 #cd1 p4 #djd4 #cgd ,vid4 op4 cit4 #c1 p4 #dee4 #cge ,osborne and ,voorhees1 vid4 op4 cit4 #cd1 p4 #dji4 #cgf ,vid4 op4 cit4 supra1 ,vol4 #ac1 p4 #dfd4 #cgg ,chittenden and ,osborne1 op4 cit4 supra1 ,vol4 #ad1 p4 #cb4 #cgh ,vid4 op4 cit4 supra1 p4 #da4 #cgi ,vid4 op4 cit4 supra1 p4 #fci4 #chj ,vid4 op4 cit4 supra1 ,vol4 #ac1 p4 #cii4 #cha ,vid4 op4 cit4 supra1 pp4 #cie1 #djj1 #dja4 #chb ,vid4 op4 cit4 supra1 p4 #dji4 #chc ,this work1 ,vol4 #a1 p4 #cai4 #chd ,this work1 ,vol4 #b1 pp4 #afi et seq4 #che ,vid4 op4 cit4 #dg1 p4 #dbj4 #chf ,osborne1 vid4 op4 cit4 #dd1 p4 #daj4 #chg ,hoppe-,seyler1 ,handbuch der physiologisch- und pathologisch-chemischen ,analyse4 #chh ,knig und ,bmer1 ,zeitschrift fr analytische ,chemie1 ,band #cd1 ,s4 #efj4 #chi ,this work1 ,vol4 #b1 pp4 #big1 #bih4 #cij ,vid4 op4 cit4 supra1 p4 #ahd4 #cia ,vid4 op4 cit4 supra1 p4 #bjf4 #cib ,this work1 ,vol4 ,i1 p4 #dej2 ,vol4 #b1 p4 #bbf4 #cic ,zeitschrift fr analytische ,chemie1 ,band #cd1 ,s4 #cgg4 #cid ,knig und ,bmer1 vid4 op4 cit4 supra1 ,s4 #efj4 #cie ,vid4 op4 cit4 supra1 ,s4 #efb4 #cif ,vid4 op4 cit4 #ec1 p4 #ahd4 #cig ,vid4 op4 cit4 #eg1 ,s4 #cgd4 #cih ,vid4 op4 cit4 supra1 ,s4 #efh4 #cii ,from 4 ,,part ,,sixth4 ,,dairy ,,products4 #dbf4 ,introductory4--,the importance of dairy products has led to the publication of a vast amount of literature relating thereto1 and it seems almost a hopeless task to present even a typical abstract of the various analytical processes which have been proposed and used in their study4 ,the general principles which have been developed in the preceding parts of this volume are applicable to the study of dairy products1 and the analyst who is guided by them can intelligently examine the bodies specially considered in the present part4 ,there have been developed1 however1 many valuable processes for the special examination of dairy products1 which are of such a nature that they could not be properly discussed in the preceding pages4 ,in the present part an effort will be made to present in a typical form the most important of these processes and to state the general principles on which they are based4 ,this subject is naturally subdivided into three parts1 viz41 milk1 butter and cheese4 ,the milk sugar industry is not of sufficient importance to receive a special classification4 ,,milk4 #dbg4 ,composition of ,milk4--,the composition of milk not only varies with the genus and species of the mammal from which it is derived1 but also depends in a marked degree on idiosyncrasy4#djj ,milk is a mixture containing water1 proteids1 fat1 carbohydrates1 organic and inorganic acids and mineral salts4 ,there have also been observed in milk in minute quantities ammonia1 urea1 hypoxanthin1 chyme1 chyle1 biliverdin1 cholesterin1 mucin1 lecithin1 kreatin1 leucin and tyrosin4 ,in the fermentation which milk undergoes in incipient decomposition there is sometimes developed from the proteid matter1 as pointed out by ,vaughn1 a ptomaine1 tyrotoxicon1 which is a virulent poison4#dja ,the presence of these last named bodies is of interest chiefly to the physiologist and pathologist and can receive no further attention here4 ,from a nutritive point of view1 the important components of milk are the fats1 proteids and sugar1 but especially in the nourishment of the young the value of lime and phosphoric acid must be remembered4 ,the mean composition of the most important milks1 as determined by recent analyses1 is given below3 ,water4 ,sugar4 ,proteids4 ,fat4 ,ash4 ,per cent4 ,per cent4 ,per cent4 ,per cent4 ,per cent4 ,cow #hf4ij #d4hj #c4fj #d4jj #j4gj ,human #hh4ge #f4jj #a4ej #c4de #j4cj ,goat #he4gj #d4de #d4cj #d4ge #j4hj ,ass #hi4ej #f4be #b4jj #a4ge #j4ej ,mare #ij4ge #e4gj #b4jj #a4bj #j4ce ,sheep #hj4hj #d4ij #f4ee #f4he #j4ij ,the mean composition of milk1 as given by ,watts and ,knig1 is given in the following tables3 ,,watts4 ,mineral ,water4 ,solids4 ,proteids4 ,fats4 ,sugar4 ,salts4 ,woman #hg4fe #ab4ce #c4jg #c4ia #e4ja #j4ag ,ass #ij4gj #i4cj #a4gj #a4ee #e4hj #j4ej ,cow #hf4ef #ac4dd #d4jh #d4jc #d4fj #j4gc ,goat #hf4gf #ac4bd #d4bc #d4dh #c4ia #j4fb ,sheep #hc4ca #af4fi #e4gc #f4je #c4if #j4fh ,mare #hb4hd #ag4af #a4fd #f4hg #h4fe ,k,,nig4 ,casein and ,milk ,water4 ,fat4 albumin4 sugar4 ,ash4 ,woman #hg4da #c4gh #b4bi #f4ba #j4ca ,mare #ij4gh #a4ba #a4ii #e4fg #j4ce ,ass #hi4fd #a4fc #b4bb #e4ii #j4ea ,cow #hg4ag #c4fi #c4ee #d4hh #j4ga ,the average composition of #abj1edj samples of cow milk1 as determined by analysis1 extending over a period of eleven years1 was found by ,vieth to be as follows3#djb ,per cent4 ,total solids #ab4i ,solids not fat #h4h ,fat #d4a ,the quantity of solids and fat in milk is less after longer than after shorter periods between milkings4 ,the quantity of solids and fat in cow milk is less in the spring than in the autumn4 ,the chief organic acid naturally present in milk is citric1 which exists probably in combination with lime4 ,the mean content of citric acid in milk is about one-tenth of one per cent4#djc ,citric acid is not found in human milk1 and probably exists only in the mammary secretions of herbivores4 ,among the mineral acids of milk1 phosphoric is the most important1 but a part of the phosphorus found as phosphoric acid in the ash of milk may come from pre-existing organic phosphorus 7lecithin1 nuclein74 ,the sulfuric acid1 which is found in the ash of milk1 is derived from the sulfur of the proteid matter during ignition4 ,lactic acid is developed from lactose during the souring of milk as the result of bacterial activity4 ,gases are also found in solutions of milk1 notably carbon dioxid1 which gives to freshly drawn milk its brothy appearance4 ,the ash of milk has the following composition expressed as grams per liter of the original milk3#djd ,grams ,probable form ,grams ,component4 per liter4 of combination4 per liter4 sodium chlorid #j4ifb ,chlorin #j4ij potassium chlorid #j4hcj ,,kh,,po #a4aef ,k,,hpo #j4hec ,phosphoric acid #b4db ,mg,h,p,o #j4ccf ,ca,h,p,o #j4fga ,ca7,,po7 #j4hjf ,potassium #a4hj 7as shown above7 and as potassium citrate #j4die ,sodium #j4di sodium chlorid #j4ifb ,lime #a4ij 7as shown above7 and as calcium citrate #b4acc ,magnesia #j4bj ,mg,h,p,o #j4ccf ,the percentage composition of the ash of milk1 according to ,fleischmann and ,schrott1 is expressed as follows3#dje ,per cent4 ,potassium oxid1 ,k,o #be4db ,sodium oxid1 ,na,o #aj4id ,calcium oxid1 ,ca,o #ba4de ,magnesium oxid1 ,mg,o #b4ed ,iron oxid1 ,fe,o #j4aa ,sulfuric acid1 ,,so #d4aa ,phosphoric acid1 ,p,o #bd4aa ,chlorin1 ,cl #ad4fj ------ #ajc4bh ,less ,cl as ,o #c4bh ------ #ajj4jj #dbh4 ,alterability of ,milk4--,the natural souring and coagulation of milk is attributed by most authorities to bacterial action produced by infection from the air or containing vessels4#djf ,pasteur1 however1 shows that fresh milk sterilized at a temperature of #aaj may be exposed to the air without danger of souring4#djg ,after about three days1 however1 a fermentation is set up which is totally different from that produced by the microzymes naturally present in the milk4 ,this point has been further investigated by ,bchamp1 who finds that the natural souring of milk is accomplished without the evolution of any gas1 while the fermentation produced in sterilized milk by the microbes of the air1 is uniformly attended by a gaseous development4#djh ,as a result of his investigations1 he concludes that the souring of milk takes place spontaneously by reason of milk being an organic matter1 in the physiological sense of the term1 and that this alteration is produced solely by the natural microzymes of the milk4 ,according to ,bchamp1 the milk derived from healthy animals is capable of spontaneous alteration1 which consists in the development of lactic acid and alcohol1 and of curd in those milks which contain caseinates produced by the precipitating action of the acids formed4 ,oxygen and the germs which are present in the air1 according to him1 have nothing to do with this alteration in the properties of milk4 ,milk belongs to that class of organic bodies like blood1 which are called organic from a physiological point of view1 on account of containing automatic forces which produce rapid changes therein when they are withdrawn from the living organisms4 ,after milk has become sour by the spontaneous action of the microzymes which it contains1 there are developed micro-organisms1 such as vibriones and bacteria from a natural evolution from the microzymes4 ,milk which is sterilized at a high temperature1 viz41 that of boiling water or above1 is no longer milk in the true physiological sense of that term4 ,the globules of the milk undergo changes and the microzymes a modification of their functions1 so that in milk thus altered by heat1 they are able to produce a coagulation without development of acidity4 ,the microzymes thus modified1 however1 retain to a large extent their ability to become active4 ,human milk differs from cow milk in containing neither caseinates nor casein1 but special proteid bodies1 and also a galactozyme or galactozymase functionally very different from that which exists in cow milk4 ,the extractive matter is also a special kind1 consisting of milk globules and microzymes belonging particularly to it and containing three times less phosphate and mineral salts than cow milk4 ,boiling the milk of the cow or other animals does not render it similar to that of woman4 ,there is no treatment1 therefore1 of any milk which renders it entirely suited to the nourishment of infants4 ,the composition of the milk of the cow may be represented by three groups3 #a4 ,organic elements in suspension2 consisting chiefly of the globules of the milk1 which are mostly composed of the fat1 of an epidermoid membrane containing mineral matter of special soluble albumins and of microzymes containing also mineral matter4 #b4 ,dissolved constituents2 consisting of caseinates1 lactalbuminates1 galactozymase1 holding phosphates in combination1 lactose1 extractive matter1 organic phosphates of lime1 acetates1 urea and alcohol4 #c4 ,mineral matters in solution2 consisting of sodium and calcium chlorids1 carbon dioxid and oxygen4#dji ,it will be noticed from the above classification that ,bchamp fails to mention citrate of lime4 ,it is scarcely necessary to add to this brief rsum of the theories of ,bchamp that they are entirely at variance with the opinions held by nearly all his contemporaries4 #dbi4 ,effects of ,boiling on ,milk4--,on boiling1 the albumin in milk is coagulated and on separating the proteid bodies by saturation with magnesium sulfate no albumin is found in the filtrate4 ,the total casein precipitated from boiled is therefore greater than from unboiled milk4 ,jager has shown that the casein can be precipitated from boiled milk by rennet1 but with greater difficulty than from unboiled4#daj ,according to this author in #c4ge per cent of proteid in milk there are found #c4ae per cent of casein1 #j4ce of albumin and #j4be of globulin4 #dcj4 ,appearance of the ,milk4--,the color1 taste1 odor and other sensible characters of the milk are to be observed and noted at the time the sample is secured4 ,any variation from the faint yellow color of the milk is due to some abnormal state4 ,a reddish tint indicates the admixture of blood1 while a blue color is characteristic of the presence of unusual micro-organisms4 ,odor and taste will reveal often the character of the food which the animals have eaten4 ,any marked departure of the sample from the properties of normal milk should at once lead to its condemnation for culinary or dietetic purposes4 #dca4 ,micro-,organisms of the ,milk4--,milk is a natural culture solution for the growth of micro-organisms1 and they multiply therein with almost incredible rapidity4 ,some of these are useful1 as1 for instance1 those which are active in the ripening of cream1 and others are of an injurious nature1 producing fermentations which destroy the sugars or proteids of the milk and develop acid1 alcohol1 mucous or ptomaine products4 ,it is not possible here to even enumerate the kinds of micro-organisms which abound in milk and the reader is referred to the standard works on that subject4#daa ,for analytical purposes it is important that the sample be kept as free as possible of all micro-organisms1 good or bad1 which may be accomplished by some of the methods given below4 #dcb4 ,sampling ,milk4--,it is not difficult to secure for examination representative samples of milk1 if the proper precautions be taken4 ,on the other hand1 the ease and rapidity with which a milk undergoes profound changes render necessary a careful control of the methods of taking samples4 ,the most rapid changes to which a mass of milk is obnoxious are due to the separation of the fat particles and to the action of bacteria4 ,even after standing for a few minutes1 it will be found that the fat globules are not evenly distributed4 ,before securing the sample for analysis1 it is necessary to well stir or mix the milk4 ,a mean sample may also be secured from a can of milk by the sampling tube devised by ,scovell1 which will be described below4 ,in securing samples1 a full detailed description of the cow or herd furnishing them is desirable1 together with all other data which seem to illustrate in any way the general and particular conditions of the dairy4 ,samples are to be preserved in clean1 well stoppered vessels1 properly numbered and securely sealed4 ,illustration3 ,,fig4 #ajf4--,,scovell',s ,,milk ,,sampling ,,tube4 #dcc4 ,scovell's ,milk ,sampler4--,in sampling large quantities of milk in pails or shipping cans1 it is exceedingly inconvenient to mix the milk by pouring from one vessel to another or by any easy process of stirring4 ,in order to get representative samples in such conditions1 ,scovell has put in use a sampler1 by means of which a typical portion of the milk may be withdrawn from a can without either pouring or stirring4 ,the construction of the sampler is shown in ,fig4 #ajf1 representing it in outline and longitudinal section4 ,the tube a1 made of brass1 is open at both ends and of any convenient dimensions4 ,its lower end slides in a large tube b1 closed at the bottom and having three elliptical1 lateral openings c1 which admit the milk as the tube is slowly depressed in the contents of the can4 ,in getting the sample1 a is raised as shown in profile4 ,when the bottom of b reaches the bottom of the can a is pushed down as shown in the section4 ,the milk contained in the sampler is then readily withdrawn4 #dcd4 ,preserving ,milk for ,analysis4--,pasteurizing or boiling the sample is not advisable by reason of the changes produced in the milk by heat4 ,the milk sample may be preserved by adding to it a little chloroform1 one part in #ajj being sufficient4 ,boric and salicylic acids may also be used1 but not so advantageously as formaldehyd or mercuric chlorid4 ,rideal has observed that one part of formaldehyd will preserve #aj1jjj parts of milk in a fresh state for seven days4 ,the formaldehyd sold in the trade contains about one part of formaldehyd in #cbj of the mixture4 ,one-half pint of this commercial article is sufficient for about twenty gallons of milk1 corresponding to about one part of pure formaldehyd to #de1jjj parts of milk4 ,rideal much prefers formalin 7formaldehyd7 to borax or boric acid as a milk preservative4 ,no ill effects due to its toxic action have been observed1 even when it is consumed in a one per cent solution4#dab ,samples of milk can be kept in this way from four to six weeks by adding about one drop of the commercial formaldehyd to each ounce of sample4 ,the analyst should remember in such cases that the formaldehyd may not all escape on evaporation1 on account of forming some kind of a compound with the constituents of the milk1 as is pointed out by ,bevan4#dac ,bevan suggests that the formaldehyd may not actually be retained in the sample1 but that the increase in the apparent amount of total solids is due to the conversion of the lactose into galactose4 ,this point1 however1 has not been determined4 ,richmond and ,boseley propose to detect formalin by means of diphenylamin4 ,a solution of diphenylamin is made with water1 with the help of just enough sulfuric acid to secure a proper solvent effect4 ,the liquid to be tested1 which is supposed to contain formaldehyd1 or the distillate therefrom1 is added to this solution and boiled4 ,if formaldehyd be present1 a white flocculent precipitate is deposited1 which is colored green if the acid used contain nitrates4 ,for other methods of detecting formalin and for a partial literature of the subject the paper mentioned above may be consulted4 ,one gram of fine-ground mercuric chlorid dissolved in #b1jjj grams of milk will preserve it1 practically unchanged1 for several days4 ,one gram of potassium bichromate dissolved in one liter of milk will also preserve it for some time4 ,thymol1 hydrochloric acid1 carbon disulfid1 ether and other antiseptics may also be employed4 ,no more of the preserving agent should be used than is required to keep the milk until the analysis is completed4 ,all methods of preservation are rendered more efficient by the maintenance of a low temperature1 whereby the vitality of the bacteria is greatly reduced4 #dce4 ,freezing ,point of ,milk4--,by reason of its content of sugar and other dissolved solids1 the freezing point of milk is depressed below #j4 ,a good idea of the purity of whole milk is secured by subjecting it to a kryoscopic test4 ,the apparatus employed for this purpose is that used in general analytical work in the determination of freezing points4 ,pure full milk freezes at about #j4ee below zero1 and any marked variation from this number shows adulteration or abnormal composition4#dad ,a simple apparatus1 especially adapted to milk1 is described by ,beckmann4#dae ,the kryoscopic investigation may also be extended to butter fat dissolved in benzol4 #dcf4 ,electric ,conductivity of ,milk4--,the electric conductivity of milk may also be used as an index of its composition4 ,the addition of water to milk diminishes its conductivity4#daf ,this method of investigation has at present but little practical value4 #dcg4 ,viscosity ,of ,milk4--,the viscosity of milk may be determined by the methods already described4 ,any variation from the usual degree of fluidity is indicated either by the abstraction of some of the contents of the milk1 the addition of some adulterant or the result of fermentation4 #dch4 ,acidity and ,alkalinity of ,milk4--,fresh milk of normal constitution has an amphoteric reaction4 ,it will redden blue and blue red litmus paper4 ,this arises from the presence in the milk of both neutral and acid phosphates of the alkalies4 ,a saturated alkaline phosphate1 i4 e41 one in which all the acid hydrogen of the acid has been replaced by the base has an alkaline reaction while the acid phosphates react acid4 ,when fresh milk is boiled its reaction becomes strongly alkaline and this arises chiefly from the escape of the dissolved carbon dioxid4 ,by the action of micro-organisms on the lactose of milk1 the alkaline reaction soon becomes acid1 and delicate test paper will show this decomposition long before it becomes perceptible to the taste4 ,it is advisable to test the reactions of the milk as soon as possible after it is drawn from the udder1 both before and after boiling4 #dci4 ,determination of the ,acidity of ,milk4--,in the determination of the acidity of milk it is important that it first be freed of the carbon dioxid it contains4#dag ,van ,slyke has found that too high results are obtained by the direct titration of milk for acidity1 and when the milk is previously diluted the results are also somewhat too high4#dah ,good results are got by diluting the milk with hot water and boiling for a short time to expel the carbon dioxid4 ,twenty-five cubic centimeters of milk are diluted with water to about a quarter of a liter1 as above1 two cubic centimeters of a one per cent alcoholic phenolphthalien added and the titration accomplished by decinormal alkali4 ,this variation of the methods of procedure1 suggested by ,hopkins and ,powers1 appears to be the best process at present known for the determination of acidity4 ,the reader is referred to the paper cited above for references to other methods which have been proposed4 #ddj4 ,opacity ,of ,milk4--,the white color and opacity of milk are doubtless due to the presence of the suspended fat particles and to the colloid casein4 ,on the latter it is probably principally dependent since the color of milk is not very sensibly changed after it has passed the extractor1 which leaves not to exceed one-tenth of one per cent of fat in it4 ,some idea of the quality of the milk1 however1 may be obtained by determining its opacity4 ,this is accomplished by the use of a lactoscope4 ,the one generally employed was devised by ,feser and is shown in ,fig4 #ajg4 ,the instrument consists of a cylindrical glass vessel of a little more than #ajj cubic centimeters content1 in the lower part of which is set a cone of white glass marked with black lines4 ,into this part are placed four cubic centimeters of milk4 ,a small quantity of water is added and the contents of the vessel shaken4 ,this operation is repeated until the black lines on the white glass just become visible4 ,the graduations on the left side show the volume of water which is necessary to bring the dark lines into view1 while those on the right indicate approximately the percentage of fat present4 ,among the other lactoscopes which have been used may be mentioned those of ,donn1 ,vogel1 ,hoppe-,seyler1 ,trommer1 ,seidlitz1 ,reischauer1 ,mittelstrass1 ,hnocque1 and ,heusner4#dai ,since the invention of so many quick and accurate methods of fat estimation these instruments have little more than a historical interest4 ,illustration3 ,,fig4 #ajg4--,,lactoscope1 ,,lactometer ,,and ,,creamometer4 #dda4 ,creamometry4--,the volume of cream which a sample of milk affords under arbitrary conditions of time and temperature is sometimes of value in judging the quality of milk4 ,a convenient creamometer is a small cylinder graduated in such a way that the volume of cream separated in a given time can be easily noted4 ,there are many kinds of apparatus used for this purpose1 a typical one being shown in ,fig4 #ajg4 ,the usual time of setting is twenty-four hours4 ,a quicker determination is secured by placing the milk in strong glass graduated tubes and subjecting these to centrifugal action4 ,the process is not exact and is now rarely practiced as an analytical method1 even for valuing the butter making properties of milk4 #ddb4 ,specific ,gravity4--,the specific gravity of milk is uniformly referred to a temperature of #ae4 ,generally no attempt is made to free the milk of dissolved gases beforehand4 ,this should not be done by boiling but by placing the sample in a vacuum for some time4 ,any of the methods described for determining specific gravity in sugar solutions may be used for milk 7#dh-ei74 ,the specific gravity of milk varies in general from #a4jbh to #a4jcd4 ,nearly all good cow milk from herds will show a specific gravity varying from #a4jcj to #a4jcb4 ,in extreme cases from single cows the limits may exceed those first given above1 but such milk cannot be regarded as normal4 ,increasing quantities of solids not fat in solution1 tend to increase the specific gravity1 while an excess of fat tends to diminish it4 ,there is a general ratio existing between the solids not fat and the fat in cow milk1 which may be expressed as #i3 #d4 ,the removal of cream and the addition of water in such a manner as not to affect the specific gravity of the sample disturbs this ratio4 ,the determination of the specific gravity alone1 therefore1 cannot be relied upon as an index of the purity of a milk4 #ddc4 ,lactometry4--,a hydrometer especially constructed for use in determining the density of milk is called a lactometer4 ,in this country the one most commonly used is known as the lactometer of the ,new ,york ,board of ,health4 ,it is a hydrometer1 delicately constructed1 with a large cylindrical air space and a small stem carrying the thermometric and lactometric scales4 ,it is shown held in the creamometer in ,fig4 #ajg4 ,the milk is brought to a temperature of #fj ,f4 and the reading of the lactometer scale observed4 ,this is converted into a number expressing the specific gravity by means of a table of corresponding values given below4 ,each mark on the scale of the instrument corresponds to two degrees and these marks extend from #j to #abj4 ,the numbers of this scale can be converted into those corresponding to the direct reading instrument1 described in the next paragraph1 by multiplying them by #j4bi4 ,the minimum density for whole milk at #fj ,f4 is fixed by this instrument at #ajj1 corresponding to a specific gravity of #a4jbi4 ,the instrument is also constructed without the thermometric scale4 ,the mean density of many thousand samples of pure milk1 as observed by the ,new ,york authorities1 is #a4jcai4 ,the specific gravity is easily secured1 and while not of itself decisive1 should always be determined4 ,the specific gravity of milk increases for some time after it is drawn and should be made both when fresh and after the lapse of several hours4#dbj ,,table ,,showing ,,specific ,,gravities ,,corresponding ,,to ,,degrees ,,of ,,the ,,new ,,york ,,board ,,of ,,health ,,lactometer4 ,,temperature #fj ,f4 ,degree4 ,sp4 gr4 ,degree4 ,sp4 gr4 #ij #a4jbfai #ajf #a4jcjgd #ia #a4jbfci #ajg #a4jcajc #ib #a4jbffh #ajh #a4jcacb #ic #a4jbfig #aji #a4jcafa #id #a4jbgbf #aaj #a4jcaij #ie #a4jbgee #aaa #a4jcbai #if #a4jbghd #aab #a4jcbdh #ig #a4jbhac #aac #a4jcbgg #ih #a4jbhdb #aad #a4jccjf #ii #a4jbhga #aae #a4jccce #ajj #a4jbijj #aaf #a4jccfd #aja #a4jbibi #aag #a4jccic #ajb #a4jbieh #aah #a4jcdbb #ajc #a4jbihg #aai #a4jcdea #ajd #a4jcjaf #abj #a4jcdhj #aje #a4jcjde #ddd4 ,direct ,reading ,lactometer4--,a more convenient form of lactometer is one which gives the specific gravity directly on the scale4 ,the figures given represent those found in the second and third decimal places of the number expressing the specific gravity4 ,thus #ca on the scale indicates a specific gravity of #a4jca4 ,this instrument is also known as the lactometer of ,quvenne4 ,for use with milk1 the scale of the instrument does not need to embrace a wider limit than from #be to #ce1 and such an instrument is capable of giving more delicate readings than when the scale extends from #ad to #db1 as is usually the case with the quvenne instrument4 ,langlet has invented a lactoscope with a scale1 showing the corrections to be applied for temperatures other than #ae4 ,a detailed description of this instrument1 as well as the one proposed by ,pinchon1 is unnecessary4#dba #dde4 ,density of ,sour ,milk4--,coagulated milk cannot be used directly for the determination of the specific gravity1 both because of its consistence and by reason of the fact that the fat is more or less completely separated4 ,in such a case1 the casein may be dissolved by the addition of a measured quantity of a solvent of a known specific gravity1 the density of the resulting solution determined and that of the original milk calculated from the observed data4 ,ammonia is a suitable solvent for this purpose4#dbb #ddf4 ,density of the ,milk ,serum4--,the specific gravity of the milk serum1 after the removal of the fat and casein by precipitation and filtration1 may also be determined4 ,for normal cow milk the number is about #a4jbg4 #ddg4 ,total ,solids4--,the direct gravimetric determination of the total solids in milk is attended with many difficulties1 and has been the theme of a very extended periodical literature4 ,a mere examination of the many processes which have been proposed would require several pages4 ,the most direct method of procedure is to dry a small quantity of milk in a flat-bottom dish to constant weight on a steam-bath4 ,the surface of the dish should be very large1 even for one or two grams of milk2 in fact the relation between the quantity of milk and the surface of the dish should be such that the fluid is just sufficient in amount to moisten the bottom of the dish with the thinnest possible film4 ,the dish1 during drying1 is kept in a horizontal position at least until its contents will not flow4 ,the water of the sample will be practically all evaporated in about two hours4 ,the operation may be accelerated by drying in vacuo4 ,the drying may also be accomplished by using a flat-bottom dish containing some absorbent1 such as sand1 pumice stone1 asbestos or crysolite4 ,the milk may also be absorbed by a dried paper coil and dried thereon 7#bf74 ,it is convenient to determine the water in the sample subsequently to be used for the gravimetric determination of the fat1 and this is secured by the adoption of the paper coil method1 as suggested by the author1 or by the use of a perforated metal tube containing porous asbestos1 as proposed by ,babcock4#dbc ,the process is conveniently carried out as follows3 ,provide a hollow cylinder of perforated sheet metal sixty millimeters long and twenty millimeters in diameter1 closed five millimeters from one end by a disk of the same material4 ,the perforations should be about #j4g millimeter in diameter and as close together as possible4 ,fill loosely with from one and a half to two and a half grams of dry woolly asbestos and weigh4 ,introduce a weighed quantity of milk 7about five grams74 ,dry at #ajj for four hours4 ,during the first part of the drying the door of the oven should be left partly open to allow escape of moisture4 ,cool in a desiccator and weigh4 ,repeat the drying until the weight remains constant4 ,place in an extractor and treat with anhydrous ether for two hours4 ,evaporate the ether and dry the fat at #ajj4 ,the extracted fat is weighed and the number thus obtained may be checked by drying and weighing the cylinder containing the residue4 ,the asbestos best suited for use in this process should be of a woolly nature1 quite absorbent1 and1 previous to use1 be ignited to free it of moisture and organic matter4 ,a variety of serpentine1 crysolite is sometimes used instead of asbestos4 ,when the content of water alone is desired1 it is accurately determined by drying in vacuo over pumice stone 7page #cc74 ,the methods above mentioned are typical and will prove a sufficient guide for conducting the desiccation1 either as described or by any modification of the methods which may be preferred4 #ddh4 ,calculation of ,total ,solids4--,by reason of the ease and celerity with which the density of a milk and its content of fat can be obtained1 analysts have found it convenient to calculate the percentage of total solids instead of determining it directly4 ,this is accomplished by arbitrary formulas based on the data of numerous analyses4 ,these formulas give satisfactory results when the samples do not vary widely from the normal and may be used with advantage in most cases4 ,among the earliest formulas for the calculation may be mentioned those of ,fleischmann and ,morgen1#dbd ,behrend and ,morgen1#dbe ,claus1 ,stutzer and ,meyer1#dbf ,hehner1#dbg and ,hehner and ,richmond4#dbh ,without doing more than citing these papers it will be sufficient here to give the formulas as corrected by the most recent experience4 ,in the formula worked out by ,babcock the specific gravity of the sample is represented by ,s1 the fat by ,f1 and the solids not fat by t4 ,the formula is written as follows3#dbi #ajj,s - ,,fs t 7 ----------------- - #a77bej - #b4e ,f74 #ajj - #a4jgec;,,fs ,in this formula it is assumed that the difference between the specific gravity of the milk serum and that of water is directly proportional to the per cent of solids in the serum1 but this assumption is not strictly correct4 ,even in extreme cases1 however1 the error does not amount to more than #j4je per cent4 ,since a given amount of milk sugar increases the density of a milk more than the same quantity of casein1 it is evident that the formula would not apply to those instances in which the ratio between these two ingredients is greatly disturbed1 as for instance1 the whey4 ,the formula of ,hehner and ,richmond1 in its latest form1 is expressed as follows3 ,g ,t #j4bfbe ---- #a4b;,f1 ,d in which ,t represents the total solids1 ,g the reading of the quvenne lactometer1 ,d the specific gravity1 and ,f the fat4 ,example4--,let the reading of the lactometer be #ca1 corresponding to ,d #a4jca1 and the percentage of fat be three and five-tenths1 what is the percentage of the total solids8 ,substituting these values in the formulas we have #ca ,t #j4bfbe ----- #a4b #c4e #ab4ji4 #a4jca ,to simplify the calculations1 ,richmond's formula may be written ,g #f;,f ,t ----- ----- #j4ad4 #d #e ,calculated by this shortened formula from the above data ,t #ab4ji1 the same as given in the larger formula4 ,calculating the solids not fat in the hypothetical case given above by ,babcock's formula1 we get t #h4df1 and this plus #c4e gives #aa4if1 which is slightly lower than the number obtained by the richmond process4 ,the babcock formula may be simplified by substituting the number expressing the reading of the quvenne lactometer for that donating the specific gravity1 in other words1 the specific gravity multiplied by #ajj and the quotient diminished by #ajjj4 ,the formulas for solids not fat and total solids then become ,l ,l t ---- #j4b;,f1 and ,t ----- #a4b;,f1 #d #d in which ,l represents the reading of the lactometer4 ,by the addition of the constant factor #j4ad the results calculated by the formula of ,babcock are the same as those obtained by the method of ,richmond4 ,in the following table are given the solids not fat in milks as calculated by ,babcock's formula4 ,to obtain the total solids add the per cent of fat to solids not fat4 ,to obtain total solids according to ,richmond's formula increase that number by #j4ad4 ,,table ,,showing ,,per ,,cent ,,of ,,solids ,,not ,,fat ,,in ,,milk ,,corresponding ,,to ,,qu,,venne',s ,,lactometer ,,readings ,,and ,,per ,,cent ,,of ,,fat4 ,per cent ,lactometer reading at #fj ,f4 of fat4 #bf4 #bg4 #bh4 #bi4 #cj4 #ca4 #cb4 #cc4 #cd4 #ce4 #cf4 #j4j #f4ej #f4ge #g4jj #g4be #g4ej #g4ge #h4jj #h4be #h4ej #h4ge #i4jj #j4a #f4eb #f4gg #g4jb #g4bg #g4eb #g4gg #h4jb #h4bg #h4eb #h4gg #i4jb #j4b #f4ed #f4gi #g4jd #g4bi #g4ed #g4gi #h4jd #h4bi #h4ed #h4gi #i4jd #j4c #f4ef #f4ha #g4jf #g4ca #g4ef #g4ha #h4jf #h4ca #h4ef #h4ha #i4jf #j4d #f4eh #f4hc #g4jh #g4cc #g4eh #g4hc #h4jh #h4cc #h4eh #h4hc #i4jh #j4e #f4fj #f4he #g4aj #g4ce #g4fj #g4he #h4aj #h4ce #h4fj #h4he #i4aj #j4f #f4fb #f4hg #g4ab #g4cg #g4fb #g4hg #h4ab #h4cg #h4fb #h4hg #i4ab #j4g #f4fd #f4hi #g4ad #g4ci #g4fd #g4hi #h4ad #h4ci #h4fd #h4hi #i4ad #j4h #f4ff #f4ia #g4af #g4da #g4ff #g4ia #h4af #h4da #h4ff #h4ia #i4af #j4i #f4fh #f4ic #g4ah #g4dc #g4fh #g4ic #h4ah #h4dc #h4fh #h4ic #i4ah #a4j #f4gj #f4ie #g4bj #g4de #g4gj #g4ie #h4bj #h4de #h4gj #h4ie #i4bj #a4a #f4gb #f4ig #g4bb #g4dg #g4gb #g4ig #h4bb #h4dg #h4gb #h4ig #i4bb #a4b #f4gd #f4ii #g4bd #g4di #g4gd #g4ii #h4bd #h4di #h4gd #h4ii #i4bd #a4c #f4gf #g4ja #g4bf #g4ea #g4gf #h4ja #h4bf #h4ea #h4gf #i4ja #i4bf #a4d #f4gh #g4jc #g4bh #g4ec #g4gh #h4jc #h4bh #h4ec #h4gh #i4jc #i4bh #a4e #f4hj #g4je #g4cj #g4ee #g4hj #h4je #h4cj #h4ee #h4hj #i4je #i4cj #a4f #f4hb #g4jg #g4cb #g4eg #g4hb #h4jg #h4cb #h4eg #h4hb #i4jg #i4cb #a4g #f4hd #g4ji #g4cd #g4ei #g4hd #h4ji #h4cd #h4ei #h4hd #i4ji #i4cd #a4h #f4hf #g4aa #g4cf #g4fa #g4hf #h4aa #h4cf #h4fa #h4hf #i4aa #i4cg #a4i #f4hh #g4ac #g4ch #g4fc #g4hh #h4ac #h4ch #h4fc #h4hh #i4ad #i4ci #b4j #f4ij #g4ae #g4dj #g4fe #g4ij #h4ae #h4dj #h4ff #h4ia #i4af #i4da #b4a #f4ib #g4ag #g4db #g4fg #g4ib #h4ag #h4db #h4fh #h4ic #i4ah #i4dc #b4b #f4id #g4ai #g4dd #g4fi #g4id #h4ai #h4dd #h4gj #h4ie #i4bj #i4de #b4c #f4if #g4ba #g4df #g4ga #g4if #h4ba #h4df #h4gb #h4ig #i4bb #i4dg #b4d #f4ih #g4bc #g4dh #g4gc #g4ih #h4bc #h4dh #h4gd #h4ii #i4bd #i4di #b4e #g4jj #g4be #g4ej #g4ge #h4jj #h4be #h4ej #h4gf #i4ja #i4bf #i4ea #b4f #g4jb #g4bg #g4eb #g4gg #h4jb #h4bg #h4eb #h4gh #i4jc #i4bh #i4ec #b4g #g4jd #g4bi #g4ed #g4gi #h4jd #h4bi #h4ed #h4hj #i4je #i4cj #i4ee #b4h #g4jf #g4ca #g4ef #g4ha #h4jf #h4ca #h4eg #h4hb #i4jg #i4cb #i4eg #b4i #g4jh #g4cc #g4eh #g4hc #h4jh #h4cc #h4ei #h4hd #i4ji #i4cd #i4ei #c4j #g4aj #g4ce #g4fj #g4he #h4aj #h4cf #h4fa #h4hf #i4aa #i4cf #i4fa #c4a #g4ab #g4cg #g4fb #g4hg #h4ac #h4ch #h4fc #h4hh #i4ac #i4ch #i4fd #c4b #g4ad #g4ci #g4fd #g4hi #h4ae #h4dj #h4fe #h4ij #i4ae #i4da #i4ff #c4c #g4af #g4da #g4ff #g4ib #h4ag #h4db #h4fg #h4ib #i4ah #i4dc #i4fh #c4d #g4ah #g4dc #g4fi #g4id #h4ai #h4dd #h4fi #h4id #i4bj #i4de #i4gj #c4e #g4bj #g4de #g4ga #g4if #h4ba #h4df #h4ga #h4if #i4bb #i4dg #i4gb #c4f #g4bb #g4dh #g4gc #g4ih #h4bc #h4dh #h4gc #h4ih #i4bd #i4di #i4gd #c4g #g4bd #g4ej #g4ge #h4jj #h4be #h4ej #h4ge #i4jj #i4bf #i4ea #i4gf #c4h #g4bf #g4eb #g4gg #h4jb #h4bg #h4eb #h4gg #i4jb #i4bh #i4ec #i4gh #c4i #g4bh #g4ed #g4gi #h4jd #h4bi #h4ed #h4gi #i4jd #i4cj #i4ee #i4hj #d4j #g4cj #g4ef #g4ha #h4jf #h4ca #h4ef #h4ha #i4jf #i4cb #i4eg #i4hc #d4a #g4cb #g4eh #g4hc #h4jh #h4cc #h4eh #h4hc #i4jh #i4cd #i4ei #i4he #d4b #g4cd #g4fj #g4he #h4aj #h4ce #h4fj #h4he #i4aa #i4cf #i4fb #i4hg #d4c #g4cf #g4fb #g4hg #h4ab #h4cg #h4fb #h4hh #i4ac #i4ch #i4fd #i4hi #d4d #g4ch #g4fd #g4hi #h4ad #h4ci #h4fd #h4ij #i4ae #i4dj #i4ff #i4ia #d4e #g4dj #g4ff #g4ia #h4af #h4da #h4ff #h4ib #i4ag #i4db #i4fh #i4ic #d4f #g4dc #g4fh #g4ic #h4ah #h4dc #h4fh #h4id #i4ai #i4dd #i4gj #i4ie #d4g #g4de #g4gj #g4ie #h4bj #h4de #h4gj #h4if #i4ba #i4df #i4gb #i4ig #d4h #g4dg #g4gb #g4ig #h4bb #h4dg #h4gb #h4ih #i4bc #i4dh #i4gd #i4ii #d4i #g4di #g4gd #g4ii #h4bd #h4di #h4gd #i4jj #i4be #i4ej #i4gf #aj4ja #e4j #g4ea #g4gf #h4ja #h4bf #h4ea #h4gf #i4jb #i4bg #i4eb #i4gh #aj4jc #e4a #g4ec #g4gh #h4jc #h4bh #h4ec #h4gi #i4jd #i4bi #i4ed #i4hj #aj4je #e4b #g4ee #g4hj #h4je #h4cj #h4ee #h4ha #i4jf #i4ca #i4ef #i4hb #aj4jg #e4c #g4eg #g4hb #h4jg #h4cb #h4eg #h4hc #i4jh #i4cc #i4eh #i4hd #aj4ji #e4d #g4ei #g4hd #h4ji #h4cd #h4fj #h4he #i4aj #i4cf #i4fa #i4hf #aj4aa #e4e #g4fa #g4hf #h4aa #h4cf #h4fb #h4hg #i4ab #i4ch #i4fc #i4hh #aj4ac #e4f #g4fc #g4hh #h4ac #h4ci #h4fd #h4hi #i4ae #i4dj #i4fe #i4ij #aj4ae #e4g #g4fe #g4ij #h4ae #h4da #h4ff #h4ia #i4ag #i4db #i4fg #i4ib #aj4ag #e4h #g4fg #g4ib #h4ag #h4dc #h4fh #h4id #i4ai #i4dd #i4fi #i4id #aj4ai #e4i #g4fi #g4id #h4bj #h4de #h4gj #h4if #i4ba #i4df #i4ga #i4if #aj4bb #f4j #g4ga #g4if #h4bb #h4dg #h4gb #h4ih #i4bc #i4dh #i4gc #i4ih #aj4bd #ddi4 ,determination of ,ash4--,in the determination of the solid residue obtained by drying milk1 it is important to observe the directions already given 7#bh-cb74 ,in the direct ignition of the sample1 a portion of the sulfur and phosphorus may escape oxidation and be lost as volatile compounds4 ,this loss may be avoided by the use of proper oxidizing agents or by conducting the combustion as heretofore described4#dcj ,in the official method1 it is directed to add six cubic centimeters of nitric acid to twenty of milk1 evaporate to dryness and ignite the residue at a low red heat until free of carbon4#dca ,it is doubtful if this precaution be entirely sufficient to save all the sulfur and phosphorus1 but the method is evidently more reliable than the common one of direct ignition without any oxidizing reagent whatever4 ,,estimation ,,of ,,fat4 #dej4 ,form of ,fat in ,milk4--,the fat in milk occurs in the form of globules suspended in the liquid1 in other words in the form of an emulsion4 ,many authorities have asserted that each globule of fat is contained in a haptogenic membrane composed presumably of nitrogenous matter1 but there is no convincing evidence of the truth of this opinion4 ,the weight of experimental evidence is in the opposite direction4 ,the supposed action of the membrane and the phenomena produced thereby are more easily explained by the surface tension existing between the fat globules and the menstruum in which they are suspended4 ,babcock affirms that the spontaneous coagulation of the fibrin present in milk tends to draw the fat globules into clusters1 and this tendency can be arrested by adding a little soda or potash lye to the milk as soon as it is drawn4#dcb ,the diameter of the fat globules is extremely variable1 extending in some cases from two to twenty micromillimeters4 ,in cow milk1 the usual diameters are from three to five micromillimeters4 #dea4 ,number of ,fat ,globules in ,milk4--,the number of fat globules in milk depends on their size and the percentage of fat4 ,it is evident that no definite statement of the number can be made4 ,there is a tendency1 on the part of the globules1 to diminish in size and increase in number as the period of lactation is prolonged4 ,to avoid large numbers1 it is convenient to give the number of globules in #j4jjja cubic millimeter4 ,this number may be found within wide limits depending on the individual1 race1 food and other local conditions to which the animal or herd is subjected4 ,in general1 in whole milk this number will be found between #adj and #bej4 #deb4 ,method of ,counting ,globules4--,the number of globules in milk is computed with the aid of the microscope4 ,the most convenient method is the one devised by ,babcock4#dcc ,in carrying out this computation1 capillary tubes1 from two to three centimeters long and about one-tenth millimeter in internal diameter1 are provided4 ,the exact diameter of each tube1 in at least three points1 is determined by the micrometer attachment of the microscope1 and from these measurements the mean diameter of the tube is calculated4 ,this known1 its cubic content for any given length is easily computed4 ,ten cubic centimeters of the milk are diluted with distilled water to half a liter and one end of a capillary tube dipped therein4 ,the tube is quickly filled with diluted milk and each end is closed with a little wax to prevent evaporation4 ,several of these tubes being thus prepared1 they are placed in a horizontal position on the stage of the microscope and covered with glycerol and a cover glass4 ,the tubes are left at rest for some time until all the fat globules have attached themselves to the upper surfaces1 in which position they are easily counted4 ,the micrometer is so placed as to lie parallel with the tubes1 and the number of globules1 corresponding to each division of its scale1 counted4 ,the mean number of globules corresponding to each division of the micrometer scale is thus determined4 ,to compare the data obtained with each tube they are reduced to a common basis of the number of globules found in a length of fifty divisions of the micrometer scale in a tube having a diameter of #ajj divisions1 using the formula #ajjjjn ,n ---------1 d in which n the number of globules found in the standard length of tube measured and d the diameter of the tube4 ,it is not difficult to actually count all the globules in a length of fifty divisions of the scale1 but the computation may also be made from the mean numbers found in a few divisions4 ,the usual number of globules found in a length of #j4a millimeter in a tube #j4a millimeter in diameter1 varies from fifty to one hundred4 ,example4--,the length of one division of the micrometer scale is #j4jjb millimeter1 and the internal diameter of the tube #j4a millimeter4 ,the content of a tube1 of a length of #j4jjb #ej #j4a millimeter1 is therefore #j4jjjghed cubic millimeter4 ,the cubic content of a tube #ajj scale divisions in diameter and fifty in length is #j4jjcadaf cubic millimeter4 ,the number of globules found in fifty divisions of the tubes used is #dj4 ,then the number which would be contained in a tube of a diameter of #ajj divisions of the micrometer scale and a length of fifty divisions thereof is #ajjjjn #djjjjj ,n -------- ------ #afj4 d #bejj ,since the milk is diluted fifty times1 the actual number of globules corresponding to the volume given is #hjjj4 ,it is convenient to reduce the observations to some definite volume1 exempla gratia1 #j4jjja cubic centimeter4 ,the equation for this in the above instance is #j4jjcadaf3 #j4jjja #hjjj3 x1 whence x #bbc1 number of fat globules in #j4jjja cubic millimeter4 ,in one cubic millimeter of milk there are therefore #b1bcj1jjj fat globules1 and in one cubic centimeter #b1bcj1jjj1jjj globules4 ,in a single drop of milk there are from one to two hundred million fat globules4#dcd #dec4 ,classification of ,methods of ,determining ,fat in ,milk4--,the fat1 being the most valuable of the constituents of milk1 is the subject of a number of analytical processes4 ,an effort will be made here to classify these various methods and to illustrate each class with one or more typical processes4 ,in general the methods may be divided into analytical and commercial1 those of the first class being used for scientific and of the other for trade purposes4 ,for normal milk1 some of the trade methods have proved to be quite as accurate as the more chronokleptic analytical processes to which1 in disputed cases1 a final appeal must be taken4 ,when the analyst is called upon to determine the fat in a large number of samples of milk some one of the trade methods may often be adopted with great advantage4 #ded4 ,dry ,extraction ,methods4--,among the oldest and most reliable methods of determining fat in milk1 are included those processes based on the principle of drying the milk and extracting the fat from the residue by an appropriate solvent4 ,the solvents generally employed are ether and petroleum spirit of low boiling point4 ,the methods of drying are legion4 ,in extracting with ether1 it must not be forgotten that other bodies than fat may pass into solution on the one hand and on the other any substituted glycerid1 such as lecithin or nuclein1 which may be present may escape solution1 at least in part4 ,perhaps petroleum spirit1 boiling at from #de to #fj1 is the best solvent for fat1 but it is almost the universal custom in this and other countries to use ether4 #dee4 ,the ,official ,methods4--,in the methods adopted by the ,association of ,official ,agricultural ,chemists two processes are recommended4 7#a7 ,the ,asbestos ,process3 ,in this process it is directed to extract the residue from the determination of water by the asbestos method 7#ddg7 with anhydrous pure ether until the fat is removed1 evaporate the ether1 dry the fat at #ajj and weigh4 ,the fat may also be determined by difference1 after drying the extracted cylinders at #ajj4 7#b7 ,paper ,coil ,method3 ,this is essentially the method proposed by ,adams as modified by the author4#dce ,coils made of thick filter paper are cut into strips #f4be by #fb4e centimeters1 thoroughly extracted with ether and alcohol1 or the weight of the extract corrected by a constant obtained for the paper4 ,if this latter method be used1 a small amount of anhydrous sodium carbonate should be added4 ,paper free of matters soluble in ether is also to be had for this purpose4 ,from a weighing bottle about five grams of milk are transferred to the coil by a pipette1 taking care to keep dry the lower end of the coil4 ,the coil1 dry end down1 is placed on a piece of glass1 and dried at a temperature of boiling water for one hour1 or better1 dried in hydrogen at a temperature of boiling water1 transferred to an extraction apparatus and extracted with absolute ether or petroleum spirit boiling at about #de4 ,the extracted fat is dried in hydrogen and weighed4 ,experience has shown that drying in hydrogen is not necessary4 ,the fat may be conveniently dried in partial vacuo4 #def4 ,variations of ,extraction ,method4--,the method of preparing the milk for fat extraction is capable of many variations4 ,some of the most important follow3 7#a7 ,evaporation on ,sand3 ,the sand should be pure1 dry and of uniform size of grain4 ,it may be held in a dish or tube4 ,the dish may be made of tin foil1 so that it can be introduced with its contents into the extraction apparatus after the desiccation is complete4 ,for this purpose1 it is cut into fragments of convenient size after its contents have been poured into the extractor4 ,the scissors used are washed with the solvent4 7#b7 ,evaporation on ,kieselguhr3 ,dry kieselguhr 7infusorial earth1 tripoli7 may take the place of the sand as above noted4 ,the manipulation is the same as with sand4 7#c7 ,evaporation on ,plaster of ,paris1#dcf 7,soxhlet ,method71#dcg 7#d7 ,on ,pumice ,stone1 7#e7 ,on ,powdered ,glass1 7#f7 ,on ,chrysolite3#dch ,the manipulation in these cases is conducted as with sand and no detailed description is required4 7#g7 ,evaporation on ,organic ,substances3 ,these variations would fall under the general heading of drying on paper4 ,the following materials have been used2 viz41 sponge1#dci lint1#ddj and wood pulp4#dda ,in these variations the principal precautions to be observed are to secure the organic material in a dry state and free of any matter soluble in the solvent used4 7#h7 ,dehydration with ,anhydrous ,copper ,sulfate3 ,in this process the water of the sample is absorbed by powdered anhydrous copper sulfate1 the residual mass extracted and the butter fat obtained determined by saponification and titration4#ddb ,in the manipulation about twenty grams of the anhydrous copper sulfate are placed in a mortar1 a depression made therein in such a manner that ten cubic centimeters of milk can be poured into it without wetting it through to the mortar4 ,the water is soon absorbed when the mass is ground with a little dry sand and transferred to the extractor4 ,petroleum spirit of low boiling point is used as a solvent1 successive portions of about fifteen cubic centimeters each being forced through the powdered mass under pressure4 ,two or three treatments with the petroleum are required4 ,the residual butter fat1 after the evaporation of the petroleum1 is saponified with a measured portion1 about twenty-five cubic centimeters1 of seminormal alcoholic potash lye4 ,the residual alkali is determined by titration with seminormal hydrochloric acid in the usual manner4 ,from the data obtained is calculated the quantity of alkali employed in the saponification4 ,the weight of butter fat extracted is then calculated on the assumption that #bcj milligrams of potash are required to saponify one gram of the fat4 #deg4 ,gypsum ,method for ,sour ,milk4--,in sour milk1 extraction of the dry residue with ether is attended with danger of securing a part of the free lactic acid in the extract4 ,this may be avoided1 at least in part1 by making the milk neutral or slightly alkaline before desiccation4 ,this method is illustrated by a variation of ,soxhlet's method of drying on gypsum proposed by ,khn4#ddc ,the curdled milk is treated with potash lye of forty per cent strength until the reaction is slightly alkaline4 ,for absorbing the sample before drying1 a mixture is employed consisting of twenty-five grams of plaster of paris1 four of precipitated carbonate of lime and two of acid potassium sulfate4 ,to this mixture ten grams of the milk1 rendered alkaline as above noted1 are added in a desiccating dish1 the excess of moisture evaporated at #ajj1 the residual mass finely ground and extracted with ether for four hours4 ,a little gypsum may be found in the solution1 but in such small quantities as not to interfere seriously with the accuracy of the results obtained4 #deh4 ,estimation of ,fat in ,altered ,milk4--,in altered milk the lactose has usually undergone a fermentation affording considerable quantities of lactic acid4 ,if such milks be treated by the extraction method for fat1 the results will always be too high1 because of the solubility of lactic acid in ether4 ,vizern#ddd has proposed to avoid this error by first warming the soured milk for a few minutes to #dj1 at which temperature the clabber is easily divided by vigorous shaking4 ,of the milk thus prepared1 thirty grams are diluted with two or three volumes of water and poured onto a smooth and moistened filter4 ,the vessel and filter are washed several times until the filtrate presents no further acid reaction4 ,the filter and its contents are next placed in a vessel containing some fine washed sand4 ,a small quantity of water is added1 sufficient to form a paste4 ,with a stirring rod1 the filter is entirely broken up and the whole mass thoroughly mixed4 ,dried on the water bath the material is subjected to extraction in the ordinary way4 ,several analyses made on fresh milk and on milk kept for several months show that almost identical results are obtained4 ,in respect of this process there would be danger1 on long standing1 of the formation of free acids from butter glycerids1 and these acids would be removed by the process of washing prescribed4 ,in this case the quantity of fat obtained would be less than in the original sample4 #dei4 ,comparison of ,methods4--,an immense amount of work has been done by analysts in comparing the various types of extraction methods outlined above4#dde ,the consensus of opinion is that good results are obtained by all the methods when properly conducted1 and preference is given to the two methods finally adopted by the ,association of ,official ,chemists4 ,as solvents1 pure ether and petroleum spirit of low boiling point are preferred4 ,the direct extraction gravimetric processes are important1 since it is to these that all the other quicker and easier methods must appeal for the proof of their accuracy4 #dfj4 ,wet ,extraction ,methods4--,it has been found quite impracticable to extract the fat from milk by shaking it directly with the solvent4 ,an emulsion is produced whereby the solvent itself becomes incorporated with the other constituents of the milk1 and from which it is not separated easily even with the aid of whirling4 ,the disturbing element which prevents the separation of the solvent is doubtless the colloid casein1 since1 when this is previously rendered soluble1 the separation of the solvent holding the fat is easily accomplished4 ,the principle on which the methods of wet extraction are based is a simple one2 viz41 to secure a complete or partial solution of the casein and subsequently to extract the fat with a solvent immiscible with water4 ,the methods may be divided into three great classes2 viz41 7#a7 those in which the solvent is evaporated from the whole of the extracted fat and the residual matters weighed2 7#b7 processes in which an aliquot part of the fat solution is employed and the total fat calculated from the data secured2 7#c7 the density of the fat solution is determined at a definite temperature and the percentage of fat corresponding thereto determined from tables or otherwise4 ,methods 7#a7 and 7#b7 are practically identical in principle and one or the other may be applied according to convenience or to local considerations4 ,the methods may be further subdivided in respect of the reagents used to secure complete or partial solution of the casein1 as1 for instance1 alkali or acid4#ddf #dfa4 ,solution in an ,acid4--,a good type of these processes is the method of ,schmid4#ddg ,in this process ten cubic centimeters of milk are placed in a test tube of about five times that content1 graduated to measure small volumes4 ,an equal quantity of hydrochloric acid is added1 the mixture shaken1 boiled until it turns dark brown1 and cooled quickly4 ,the fat is extracted by shaking with thirty cubic centimeters of ether4 ,after standing some time the ethereal solution separates and its volume is noted4 ,an aliquot part of the solution is removed1 the solvent evaporated1 and the weight of fat in the whole determined by calculation4 ,the schmid process has been improved by ,stokes1#ddh ,hill1#ddi and ,richmond4#dej ,the most important of these variations consists in weighing instead of measuring the milk employed1 thus insuring greater accuracy4 ,dyer and ,roberts affirm that the ether dissolves some of the caramel products formed on boiling condensed milk with hydrochloric acid1 and that the data obtained in such cases by the process of ,schmid are too high4#dea ,since lactic acid is also slightly soluble in ether1 sour milk should not be extracted with that solvent4 ,in these cases petroleum spirit1 or a mixture of petroleum and ether1 as suggested by ,pinette1 may be used4#deb ,another variation consists in extracting the fat with several portions of the solvent and evaporating all the extracts thus obtained to get the total fat4 ,this method is perhaps the best of those in which the fat is extracted from the residual liquid after the decomposition of the casein by an acid1 and may be recommended as both reliable and typical within the limitations mentioned above4 #dfb4 ,solution in an ,alkali4--,the casein of milk is not so readily dissolved in an alkali as in an acid1 but the solution is sufficient to permit the extraction of the fat4 ,soda and potash lyes and ammonia are the alkaline bodies usually employed4 ,to promote the separation of the emulsions1 alcohol is added with advantage4 ,the principle of the process rests on the observed power of an alkali to free the fat globules sufficiently to allow them to dissolve in ether or some other solvent4 ,when the solvent has separated from the emulsion at first formed1 the whole or a part of it is used for the determination of fat in a manner entirely analogous to that employed in the process with the acid solutions described above4 ,there are many methods based on this principle1 and some of the typical ones will be given below4 ,experience has shown that extraction from an alkaline solution is more troublesome and less perfect than from an acid and these alkaline methods are1 therefore1 not so much practiced now as they were formerly4 #dfc4 ,method of ,short4--,instead of measuring the volume of the separated fat1 ,short has proposed a method in which the casein is dissolved in an alkali and the fat at the same time saponified4 ,the soap thus produced is decomposed by sulfuric acid and the volume of the separated fat acids noted4 ,this volume represents eighty-seven per cent of the corresponding volume of fat4#dec ,the solvent employed is a mixture of sodium and potassium hydroxids1 containing in one liter #abe and #aej grams1 respectively1 of these alkalies4 ,the sample of milk is mixed with half its volume of the reagent and placed in boiling water for two hours4 ,by this treatment the casein is dissolved and the fat saponified4 ,after cooling to about #fj1 the soap is decomposed by the addition of equal parts of sulfuric and acetic acids4 ,the tubes containing the mixture are again placed in boiling water for an hour and they are then filled with boiling water to within one inch of the top4 ,the tubes may either be furnished with a graduation or the column of fat be measured by a scale4 #dfd4 ,method of ,thrner4--,the process of ,short is conducted by ,thrner as follows3#ded ,ten cubic centimeters of milk measured at #ae are saponified1 in tubes fitting a centrifugal1 by the addition of one and a half cubic centimeters of an alcoholic potash lye1 containing #afj grams of potassium hydroxid per liter1 or one cubic centimeter of an aqueous fifty per cent soda lye4 ,the saponification is hastened by setting the tubes in boiling water1 where they remain for two minutes4 ,the soap formed is decomposed with a strong acid1 sulfuric preferred1 the tubes placed in the centrifugal and whirled for four minutes1 when the fat acids will be formed in the narrow graduated part of the tube and the volume occupied thereby is noted after immersion in boiling water4 ,thrner's process is not followed in this country1 but is used to a considerable extent in ,germany4#dee #dfe4 ,liebermann's ,method4--,in this method1 fifty cubic centimeters of milk1 at ordinary temperatures1 are placed in a glass cylinder twenty-five centimeters high and about four and a half internal diameter2 five cubic centimeters of potash lye of #a4bg specific gravity are added1 the cylinder closed with a well fitting cork stopper and thoroughly shaken4#def ,after shaking1 fifty cubic centimeters of petroleum spirit1 boiling point about #fj1 are added4 ,the cylinder is again stoppered and vigorously shaken until an emulsion is formed4 ,to this emulsion fifty cubic centimeters of alcohol of ninety-five per cent strength are added1 and the whole again thoroughly shaken4 ,after four or five minutes the petroleum spirit1 containing the fat1 separates4 ,in order to insure an absolute separation of the fat1 however1 the shaking may be repeated three or four times for about one-quarter minute1 waiting each time between the shakings until the spirit separates4 ,of the separated petroleum spirit twenty cubic centimeters are placed in a small weighed flask4 ,the use of the flask is recommended on account of the ease with which the petroleum spirit can be evaporated without danger of loss of fat4 ,instead of the flask a weighed beaker or other weighed dish may be employed4 ,the petroleum spirit is carefully evaporated on a water-bath and the residue dried at #aaj to #abj for one hour4 ,the weight found multiplied by five gives the content of fat in #ajj cubic centimeters of the milk4 ,the percentage by weight can then be calculated by taking into consideration the specific gravity of the milk employed4 ,the results obtained by this method agree well with those obtained by the paper coil method1 when petroleum spirit instead of sulfuric ether is used as the solvent for the fat4 ,sulfuric ether1 however1 gives an apparently higher content of fat because of the solution of other bodies not fat present in the milk4 #dff4 ,densimetric ,methods4--,instead of evaporating the separated fat solution and weighing the residue1 its density may be determined and the percentage of fat dissolved therein obtained by calculation1 or more conveniently from tables4 ,the typical method of this kind is due to ,soxhlet1 and until the introduction of modern rapid volumetric processes1 it was used perhaps more extensively than any other proceeding for the determination of fat in milk4#deg ,the reagents employed in the process are ether saturated with water and a potash lye containing #djj grams of potash in a liter4 ,the principle of the process is based on the assumption that a milk made alkaline with potash will give up all its fat when shaken with ether and the quantity of fat in solution can be determined by ascertaining the specific gravity of the ethereal solution4 ,illustration3 ,,fig4 #ajh4 ,,areometric ,,fat ,,apparatus4 ,the apparatus is arranged as shown in ,fig4 #ajh1 whereby it is easy to drive the ethereal fat solution into the measuring vessel by means of the bellows shown4 ,in the bottle1 seen at the right of the engraving are placed #bjj cubic centimeters of milk1 ten of the potash lye and sixty of the aqueous ether4 ,the milk and potash are first added and well shaken1 the ether then added1 and the contents of the bottle are shaken until a homogeneous emulsion is formed4 ,the bottle is then set aside for the separation of the ethereal solution1 which is promoted by gently jarring it from time to time4 ,when the chief part of the solution has separated1 a sufficient quantity of it is driven over into the measuring apparatus1 by means of the air bulbs1 to float the hydrometer contained in the inner cylinder4 ,after a few moments the scale of the oleometer is read and the percentage of fat calculated from the table4 ,all the measurements are made at a temperature of #ag4e4 ,the temperature is preserved constant by filling the outer cylinder of the apparatus with water4 ,if the room be warmer than #ag4e1 the water added should be at a temperature slightly below that and vice versa4 ,the oleometer carries a thermometer which indicates the moment when the reading is to be made4 ,the scale of the oleometer is graduated arbitrarily from #dc to #ff1 corresponding to the specific gravities #j4gdc and #j4gff1 respectively1 or to corresponding fat contents of #b4jg and #e4ab per cent1 in the milk1 a range which covers most normal milks4 ,in the use of the table the per cents corresponding to parts of an oleometer division can be easily calculated4 ,,table ,,for ,,calculating ,,per ,,cent ,,of ,,fat ,,in ,,milk ,,by ,,areometric ,,method ,,of ,,soxhlet4 ,reading of ,per cent fat ,reading of ,per cent fat oleometer4 in milk4 oleometer4 in milk4 #dc #b4jg #ee #c4di #dd #b4ah #ef #c4fc #de #b4cj #eg #c4ge #df #b4dj #eh #c4ij #dg #b4eb #ei #d4jc #dh #b4fd #fj #d4ah #di #b4gf #fa #d4cb #ej #b4hh #fb #d4dg #ea #c4jj #fc #d4fc #eb #c4ab #fd #d4gi #ec #c4be #fe #d4ie #ed #c4cg #ff #e4ab #dfg4 ,application of the ,areometric ,method4--,soxhlet's method1 as outlined above1 with many modifications1 has been extensively used in ,europe and to a limited degree in this country1 and the results obtained are in general satisfactory1 when the sample is a mixed one from a large number of cows and of average composition4 ,the author has shown that the process is not applicable to abnormal milk and often not to milk derived from one animal alone4#deh ,the chief difficulty is found in securing a separation of the emulsion4 ,this trouble can usually be readily overcome by whirling4 ,any centrifugal machine1 which can receive the bottle in which the emulsion is made1 may be employed for that purpose4 ,since the introduction of more modern and convenient methods of fat determination1 the areometric method has fallen into disuse and perhaps is no longer practiced in this country4 ,it is valuable now chiefly from the fact that many of the recorded analyses of milk fat were made by it1 and also for its typical character in representing all methods of analysis of fat in milk based on the density of ethereal solutions4 #dfh4 ,the ,lactobutyrometer4--,a typical instrument for measuring the volume of fat in a milk is known as ,marchand's lactobutyrometer4 ,it is based on the observation that ether will dissolve the fat from milk when the casein is wholly or partly dissolved by an alkali1 and further1 that the fat in an impure form can be separated from its ethereal solution by the action of alcohol4 ,experience has shown that all the fat is not separated from the ethereal solution by this process1 and also that the part separated is a saturated solution in ether4 ,the method cannot be rigorously placed in the two classes given above1 but being volumetric demands consideration here chiefly because of its historical interest4#dei ,the instrument employed by ,marchand is a tube about thirty centimeters long and twelve in diameter1 closed at one end and marked in three portions of ten cubic centimeters each4 ,the upper part is divided in tenths of a cubic centimeter4 ,the superior divisions are subdivided so that the readings can be made to hundredths of a cubic centimeter4 ,the tube is filled with milk to the first mark and two or three drops of a twenty-five per cent solution of soda lye added thereto4 ,ether is poured in to the second mark1 the tube closed and vigorously shaken4 ,alcohol of about ninety per cent strength is added to the upper mark1 the tube closed1 shaken and allowed to stand in a vertical position1 with occasional jolting1 until the separation of the liquids is complete4 ,in order to promote the separation the tube is placed in a cylinder containing water at #dj4 ,when the separation is complete the milk serum is found at the bottom1 the mixture of alcohol and ether in the middle and the fat at the top4 ,the mixture of ether and alcohol contains #j4abf gram of fat1 and each cubic centimeter of the separated ether fat #j4bcc gram of fat4 ,the total volume of the separated fat1 multiplied by #j4bcc1 and the product increased by #j4abf1 will give the weight of fat in the ten cubic centimeters of milk employed4 ,example4--,milk used1 ten cubic centimeters of #a4jcb specific gravity #aj4cb grams4 ,the observed volume of the saturated ether fat solution is two cubic centimeters4 ,then the weight of fat is #b #j4bcc #j4abf #j4eib gram4 ,the percentage of fat in the sample is #j4eib #ajj #aj4cb #e4gd4 ,in the apparatus used in this laboratory the upper division of the graduation is marked #ab4f1 because this represents the quantity of fat which remains in the ether-alcohol mixture for one liter of milk4 ,from this point the graduation is extended downward to ninety-five1 which1 for ten cubic centimeters of milk1 represents #j4ie gram4 ,after the fat has separated1 enough ninety-five per cent alcohol is added to bring the upper surface exactly to the graduation #ab4f4 ,the number of grams per liter of milk is then read directly from the scale4 ,in respect of applicability1 the observation made regarding ,soxhlet's areometric method may be repeated4 ,in practical work in this country the lactobutyrometer is no longer used1 but many of the recorded determinations of fat in milk have been made by this method4 #dfi4 ,volumetric ,methods4--,for practical purposes1 the volumetric methods of estimating fat in milk have entirely superseded all the other processes4 ,it has been found that the fat readily separates in a pure state from the other constituents of milk whenever the casein is rendered completely soluble2 whereas no process has yet been devised whereby the fat can be easily separated in a pure state from milk which has not been treated with some reagent capable of effecting a solution of the casein4 ,the volumetric methods may be divided into two classes2 viz41 7#a7 ,those in which the fat is separated by the simple action of gravity1 and 7#b7 those in which the natural action of gravity is supplanted by centrifugal motion4 ,each of these classes embraces a large number of variations and some of the typical ones will be described in the following paragraphs4 ,as solvents for the casein a large number of reagents has been used1 including alkalies and single and mixed acids4 ,in practice1 preference is given to the least complex and most easily prepared solvents4 #dgj4 ,method ,of ,patrick4--,a typical illustration of the method of collecting the fat after solution of the casein1 without the aid of whirling1 is found in the process devised by ,patrick4#dfj ,the solvent employed is a mixture of acetic1 sulfuric and hydrochloric acids1 saturated with sodium sulfate1 in the respective volumetric proportions of nine1 five and two4 ,the separation is accomplished in a large test tube drawn out near the top into a constricted neck which is graduated to measure the volume of the separated fat or to give direct percentage results4 ,the tube should have a content of about twenty-five cubic centimeters below the upper mark on the neck4 ,in use #aj4d cubic centimeters of milk and a sufficient quantity of the mixed acids to fill it nearly to the upper mark are placed in the tube1 together with a piece of pumice stone1 and the mixture boiled4 ,on cooling below #ajj1 the fat will separate and the volume thereof may be measured in the constricted portion of the tube4 ,the volume of the fat may be converted into weight on multiplying by #j4hh at #fj1 or more conveniently the percentage of fat be taken from a table4 ,in practice1 the tube is filled with the milk and acid mixture nearly up to the neck1 its contents well mixed and additional acid mixture added until the liquid is raised in the tube above the neck4 ,after mixing a second time1 the contents are boiled for five minutes and the fat allowed to collect in the expanded part of the tube above the neck4 ,when the fat has collected1 the mixture is boiled gently a second time for a few minutes4 ,by this treatment the fat is mixed with the upper portions of the acid liquid and clarified4 ,the clearing of the fat may be hastened by sprinkling over it a little effloresced sodium sulfate4 ,the fat is brought into the graduated neck by opening a small orifice in the belly of the tube1 which is closed by means of a rubber band4 ,when the temperature has reached #fj1 the space occupied by the fat is noted and the numbers obtained express the percentage of fat in the sample4 ,this process is illustrative of the principle of analysis1 but is no longer used in analytical determinations4 #dga4 ,the ,lactocrite4--,one of the earliest methods for fat estimation in milk1 depending on the solution of the casein and the collection of the fat by means of whirling1 is based on the use of a centrifugal machine known as the lactocrite4 ,this apparatus is modeled very like the machine usually employed for creamery work1#dfa and at one time was extensively used1 but it has now given place to less troublesome and expensive machines4 ,the acid mixture for freeing the fat of casein is composed of glacial acetic acid carrying five per cent of sulfuric4 ,the samples of milk are heated with the acid mixture in test tubes provided with stoppers and short glass tubes to return the condensation products4 ,the hot mixture is poured into a small metallic cylindrical cup holding about three cubic centimeters4 ,this cup fits by means of an accurately ground shoulder on a metal casing1 carrying inside a heavy glass graduated tube of small internal diameter4 ,the excess of the milk mixture escapes through a small aperture in the metallic screw cap of the metal holder4 ,the metal holder is cut away on both sides in order to expose the graduations on the glass tube4 ,the glass tube is held water-tight by means of perforated elastic washers4 ,thus prepared the tubes are inserted in the radial holes of a revolving steel disk previously heated to a temperature of #fj4 ,the whirling is accomplished in a few minutes by imparting to the steel disk a speed of about #f1jjj revolutions per minute4 ,at the end of this operation the fat is found in a clear column in the small glass tube and the number of the divisions it occupies in this tube is noted4 ,each division of the scale represents one-tenth per cent of fat4 ,this apparatus is capable of giving accurate results when all its parts are in good working order4 ,in this laboratory the chief difficulty which its use has presented is in keeping the joints in the glass metal tube tight4 ,this description of the apparatus is given to secure an illustration of the principle involved1 a principle which has been worked out in later times into some of the most rapid and practical processes of estimating fat in milk4 #dgb4 ,modification of ,lindstrm4--,many modifications have been proposed for conducting the determination of fat by means of the lactocrite1 but they do not involve any new principle and are of doubtful merit4 ,in the modification suggested by ,lindstrm1 which has attained quite an extended practical application1 the solvent mixture is composed of lactic and sulfuric acids and the butyrometer tubes are so changed as to permit the collection of the fat in the graduated neck after whirling1 by means of adding water4 ,the apparatus is also adjusted to secure the congelation of the fat column before its volume is noted4#dfb ,the analyst can read the fat volume at his leisure when it is in the solid state and is not confused by changes of volume during the observation4 ,the best acid mixture has been found to be composed of #ajj volumes of lactic1 an equal amount of acetic and fifteen volumes of sulfuric acids4#dfc ,illustration3 ,,fig4 #aji4 ,,babcock',s ,,butyrometer ,,and ,,acid ,,measure4 #dgc4 ,the ,babcock ,method4--,among the many quick volumetric methods which have been proposed for the determination of fat in milk1 none has secured so wide an application as that suggested by ,babcock4#dfd ,the chief point of advantage in the use of this method is found in effecting the solution of the casein by means of sulfuric acid of about #a4hc specific gravity4 ,by this reagent the casein is dissolved in a few moments without the aid of any other heat than that generated by mixing the milk with the reagent4 ,the bottle in which the separation is made is shown in ,fig4 #aji4 ,the graduations on the neck are based on the use of eighteen grams of milk4 ,to avoid the trouble of weighing1 the milk is measured from a pipette graduated to deliver eighteen grams of milk of the usual specific gravity4 ,while it is true that normal milk may vary somewhat in its density1 it has been found that a pipette marked at #ag4f cubic centimeters delivers a weight which can be safely assumed to vary but slightly from the one desired4 ,the graduated bottle holds easily thirty-five cubic centimeters of liquid in its expanded portion and the volume of milk just noted is mixed with an equal volume of sulfuric acid1 conveniently measured from the lip cylinder shown in the figure4 ,the complete mixture of the milk and acid is effected by gently rotating the bottle until its contents are homogeneous4 ,the final color of the mixture varies from dark brown to black4 ,while still hot1 the bottles are placed in a centrifugal machine and whirled for at least five minutes4 ,the most convenient machine1 where it is available1 is the one driven by a jet of steam4 ,the revolutions of the centrifugal should be at least #gjj per minute for a twenty inch and #a1bjj for a twelve inch wheel4 ,after five minutes the bottles are removed and filled to the upper mark or nearly so with hot water1 replaced in the machine and whirled for at least one minute4 ,the fat will then be found in a clearly defined column in the graduated neck of the bottle4 ,in reading the scale1 the extreme limits between the lowest point marked by the lower meniscus and the highest point marked by the edge of the upper meniscus are to be regarded as the termini of the fat column4 ,in testing cream by the babcock process1 it may either be diluted until the column of fat secured is contained in the graduated part of the neck or specially graduated bottles may be used4 ,condensed ,milk3 ,in applying the babcock test to condensed milk1 it is necessary to weigh the sample and to use only about eight grams4#dfe ,this quantity is placed in the bottle and dissolved in ten cubic centimeters of water and the analysis completed as above4 ,the reading noted is multiplied by eighteen and divided by the weight of the sample taken4 ,skim ,milk3 ,in determining the fat in skim milk and whey1 it is desirable to use a bottle of double the usual capacity1 but with the same graduation on the neck4 ,the percentage of fat noted is divided by two4 ,cheese3 ,five grams are a convenient quantity of cheese to employ4 ,to this quantity in the bottle are added fifteen cubic centimeters of hot water and the flask gently shaken and warmed until the cheese is softened4 ,the treatment with acid and whirling are the same as described above4 ,the noted reading is multiplied by eighteen and divided by five4 #dgd4 ,solution in ,amyl ,alcohol and ,hydrochloric and ,sulfuric ,acids4--,leffmann and ,beam have proposed to aid the solution of the casein in sulfuric acid by the previous addition to the milk of a mixture of equal volumes of amyl alcohol and hydrochloric acid4#dff ,in this process the same graduated flasks may be used as in the babcock process1 or a special flask may be employed4 ,in this case the graduation of the neck is for fifteen cubic centimeters of milk1 and each one and a half cubic centimeters is divided into eighty-six parts4 ,the quantity of milk noted is placed in the flask1 together with three cubic centimeters of the mixture of amyl alcohol and hydrochloric acid1 and well shaken4 ,to the mixture1 sulfuric acid of #a4hc specific gravity is added until the belly of the flask is nearly full and the contents well mixed by shaking4 ,when the casein is dissolved1 the addition of the sulfuric acid is continued until the flask is filled to the upper mark and again the contents mixed4 ,it is well to close the mouth of the flask with a stopper while shaking4 ,the bottle is placed in a centrifugal and whirled for a few moments1 when the fat is collected in the graduated neck and its volume noted4 ,the process is also known in this country as the beimling method4#dfg ,the fat separated in the above process is probably mixed with a little fusel oil1 and therefore it is advisable to use the specially graduated bottle instead of one marked in absolute volumes4#dfh ,the method1 when conducted according to the details found in the papers cited1 gives accurate results1 but is somewhat more complicated than the babcock process and is not now used to any great extent in analytical work4 #dge4 ,method of ,gerber4--,the method proposed by ,gerber for estimating fat in milk is based on the processes of ,babcock1 ,beimling and ,beam already described4 ,the tubes in which the decomposition of the milk and the measurement of the fat are accomplished are of two kinds1 one open at only one end for milk and the other open at both ends for cheese4 ,they are closed during the separation by rubber stoppers4#dfi ,illustration3 ,,fig4 #aaj4 ,,gerber',s ,,butyrometers4 ,the apparatus have been greatly improved and simplified since the first description of them was published and have come into extensive use in ,europe and to a limited extent in this country4#dgj ,the butyrometer tubes are made of various sizes and shapes1 but the most convenient are those noted above as shown in ,fig4 #aaj4 ,before adding the strong sulfuric acid1 one cubic centimeter of amyl alcohol is mixed with the milk in the butyrometer4 ,this admixture serves to clarify the fat and render the reading more easy4 ,the centrifugal is run by hand1 and the required speed of rotation is given it by means of a cord wrapped spirally about its axis1 as shown in ,fig4 #aaa4 ,the cord in the new machines is replaced by a leather strap working on a ratchet4 ,illustration3 ,,fig4 #aaa4 ,,gerber',s ,,centrifugal4 ,the process is more speedy than that of ,babcock1 and the results have been shown by a large experience to be reliable and accurate4 ,the sulfuric acid employed is of #a4hbe to #a4hcj specific gravity4 ,there is no danger of loss by the formation of volatile ethers where the quantity of amyl alcohol used does not exceed one cubic centimeter4 ,in a comparison of the respective merits of the methods of ,babcock1 ,thrner and ,gerber1 made by ,hausamann1 the first place is awarded to the ,gerber process4#dga ,in the figure #aaj1 the butyrometers marked #b1 #e and #h are for milk1 and those numbered #a1 #c and #g are for cream and cheese4 ,in conducting the analysis1 ten cubic centimeters of the sulfuric acid are placed in the butyrometer with one cubic centimeter of the amyl alcohol4 ,when mixed1 eleven cubic centimeters of the milk are added and the contents of the tube well mixed1 the tube stoppered and placed in the centrifugal4 ,the larger tubes1 open at both ends1 require double the quantities of the reagents mentioned4 ,the measurements are made at about #ae4 ,minute directions for conducting the analyses with milk1 skim milk1 buttermilk1 cream1 condensed milk1 cheese and butter accompany each apparatus4 ,,proteid ,,bodies ,,in ,,milk4 #dgf4 ,kinds of ,proteid ,bodies in ,milk4--,the proteid bodies in milk are all found in at least partial solution4 ,some authorities state that a portion of the casein is present in the form of fine particles suspended after the manner of the fat globules4#dgb ,the number and kind of proteid bodies are not known with definiteness4 ,among those which are known with certainty are casein1 albumin1 peptone and fibrin4 ,the latter body was discovered in milk by ,babcock4#dgc ,lactoglobulin and lactoprotein are also names given to imperfectly known proteid bodies in milk4 ,lactoprotein is not precipitated either by acids or by heat and is therefore probably a peptone4 ,by far the greater part of the proteid matters in milk is casein4 ,casein has been called caseinogen by ,halliburton1#dgd and paracasein by ,schulze and ,rse4#dge ,casein has intimate relations to the mineral matters in milk1 and is probably itself made up of several proteid bodies of slightly differing properties4 ,in general all that class of proteid matter contained in milk which is precipitated by rennet or a weak acid1 or spontaneously on the development of lactic acid1 is designated by the term casein1 while the albumins and peptones in similar conditions remain in solution4 ,casein contains phosphorus1 presumably as nuclein4 ,fibrin is recognized in milk by the reactions it gives with hydrogen peroxid or gum guiacum4 ,the decomposition of hydrogen peroxid is not a certain test for fibrin1 inasmuch as pus and many other bodies will produce the same effect4 ,if the milk decompose hydrogen peroxid1 however1 before and not after boiling1 an additional proof of the presence of fibrin is obtained1 since boiled fibrin does not act on the reagent4#dgf ,the gum guiacum test is applied by dipping a strip of filter paper into the milk and drying4 ,the solution of gum guiacum is applied to the dried paper and the presence of fibrin is recognized by the blue color which is produced4 ,the fibrin is probably changed into some other proteid during the ripening of cream in which the fibrin is chiefly found4 ,the albumin in milk is coagulated by boiling1 while the casein remains practically unaffected when subjected to that temperature4 #dgg4 ,estimation of ,total ,proteid ,matter4--,the total proteid matter in milk is determined by any of the general methods applicable to the estimation of total nitrogen1 but the moist combustion method is by far the most convenient4 ,from the total nitrogen1 that which represents ammonia or other nonproteid nitrogenous bodies1 is to be deducted and the remainder multiplied by an appropriate factor4 ,practically all the nitrogen obtained is derived from the proteid matters and1 as a rule1 no correction is necessary4 ,the factors employed for calculating the weight of proteid matter from the nitrogen obtained vary from #f4be to #g4jd4 ,it is desirable that additional investigations be made to determine the magnitude of this factor4 ,it is suggested that provisionally the factor #f4dj be used4 ,in the method adopted by the ,association of ,official ,agricultural ,chemists it is directed that about five grams of milk be placed in the oxidizing flask and treated without previous evaporation exactly as described for the estimation of total nitrogen in the absence of nitrates4 ,the nitrogen obtained is multiplied by #f4be to get the total proteid matter4#dgg ,in order to prevent the too great dilution of the sulfuric acid1 the milk may be evaporated to dryness or nearly so before oxidation4 ,in this laboratory it is conveniently done by placing the milk first in the oxidizing flask1 connecting this with the vacuum service and placing the flask in hot water4 ,the aqueous contents of the milk are quickly given off at a temperature not exceeding #he1 and the time required is only a few minutes4 ,the milk may also be dried in dishes made of thin glass or tin foil and1 after desiccation1 introduced with the fragments of the dishes into the oxidizing flask4 ,the preliminary drying in the oxidizing flask is recommended as the best4 ,sldner oxidizes the nitrogen in human milk by boiling ten cubic centimeters thereof for three hours with twenty-five of sulfuric acid1 fifty milligrams of copper oxid and three drops of a four per cent platinic chlorid solution1 and1 after distilling the ammonia1 uses the factor #f4ci for calculating the proteid matter4 ,according to this author human milk is much less rich in nitrogenous constituents than is generally supposed1 containing not more than one and a half per cent thereof in average samples collected at least a month after parturition4#dgh #dgh4 ,precipitation of ,total ,proteids with ,copper ,sulfate4--,this method of throwing out the total proteids of milk is due to ,ritthausen4#dgi ,the proteids and fat are precipitated together by the addition of a measured volume of copper sulfate solution1 containing #fc4ib grams of the crystallized salt in one liter4 ,the process1 as modified by ,pfeiffer1 is conducted as follows3#dhj ,ten grams of milk are diluted with ten times that much water1 five cubic centimeters of the copper sulfate solution added and then soda lye solution drop by drop until the copper is just precipitated4 ,this is determined by testing a few drops of the filtrate with soda lye1 which1 when the copper is precipitated1 will give neither a turbidity nor a blue color4 ,the mixture is poured into a dry tared filter1 the precipitate washed with hot water1 dried to constant weight and weighed4 ,the fat is removed from the dry pulverized mass by extraction with ether and the residue dried and weighed4 ,the quantity of copper oxyhydrate contained in the precipitate is calculated from the quantity of the copper solution used and amounts to #j4bjbf gram4 ,the casein thus prepared contains not only the copper compound named1 but also some of the sodium sulfate formed on the addition of the soda lye and other mineral salts present in the milk and from which it is quite impossible to completely free it4 ,there are also many other objections to the process1 and the product is of such a nature as to render the data obtained by the method very doubtful4 ,this method is chiefly valuable on account of its historical interest4 ,not only are the drying and weighing of the precipitate rendered unnecessary by the modern methods of determining nitrogen1 but there are numerous sources of error which seem to throw doubt on the accuracy of the results4 ,the copper hydroxid does not lose all its water even on drying at #abe4dha ,the method therefore can only be recommended for practical purposes when all the tedious processes of drying1 extracting and calculating the quantity of copper oxid are abandoned and the moist washed precipitate used directly for the determination of nitrogen4 #dgi4 ,proteid ,bodies by ,ammonium ,sulfate4--,all the proteid bodies except peptones are precipitated from milk on saturation with ammonium sulfate4 ,this method has little analytical value because of the presence of nitrogenous salt in the precipitate4 ,zinc sulfate may be substituted for the ammonium salt and thus a determination of proteid matter other than peptone be obtained4 ,this result subtracted from the total proteid nitrogen gives that due to peptone4 #dhj4 ,total ,proteid ,matter by ,tannic ,acid4--,for the determination of the total proteid matter in milk ,sebelien uses the following process4#dhb ,from three to five grams are diluted with three or four volumes of water1 a few drops of a saline solution added 7sodium phosphate1 sodium chlorid1 magnesium sulfate1 et similia71 and the proteid bodies thrown out with an excess of tannic acid solution4 ,the precipitate is washed with an excess of the precipitant and the nitrogen therein determined and multiplied by #f4cg4 #dha4 ,separation of ,casein from ,albumin4--,sebelien prefers magnesium sulfate or sodium chlorid to acetic acid as the best reagent for separating casein from lactalbumin4 ,of the two saline reagents mentioned1 the former is the better4 ,the milk is first diluted with a double volume of the saturated saline solution and then the fine powdered salt added until saturation is secured4 ,the casein is completely thrown out by this treatment1 collected on a filter1 washed with the saturated saline solution1 and the nitrogen therein determined4 ,the difference between the total and casein nitrogen gives the quantity due to the albumin plus the almost negligible quantity due to globulin4#dhc #dhb4 ,van ,slyke's ,method of ,estimating ,casein4--,the casein may be separated from the other albuminoids in milk by the procedure proposed by ,van ,slyke4#dhd ,ten grams of the fresh milk are diluted with ninety cubic centimeters of water and the temperature raised to #dj4 ,the casein is thrown down with a ten per cent solution of acetic acid1 of which about one and a half cubic centimeters are required4 ,the mixture is well stirred and the precipitate allowed to subside4 ,the whey is decanted onto a filter1 and the precipitate washed two or three times with cold water1 brought finally onto the filter and washed once or twice with cold water4 ,the filter paper and its contents are used for the determination of nitrogen in the usual way4 ,the casein is calculated from the nitrogen found by multiplication by the factor #f4be4 ,milk may be preserved for this method of determination by adding to it one part of finely powdered mercuric chlorid for each two thousand parts of the sample4 ,the method is not applicable to curdled milk4 #dhc4 ,theory of ,precipitation4--,most authorities now agree in supposing that the state of semisolution in which the casein is held in milk is secured by the presence of mineral matters in the milk1 in some intimate combination with the casein4 ,among these bodies lime is of the most importance4 ,the action of the dilute acid is chiefly on these mineral bodies1 releasing them from combination with the casein1 which1 being insoluble in the milk serum1 is precipitated4 #dhd4 ,factors for ,calculation4--,most analysts still use the common proteid factor1 #f4be1 in calculating the quantity of proteids from the nitrogen determined by analysis4 ,for casein many different factors have been proposed4 ,according to ,makeris the factor varies from #f4hc to #g4jd4dhe ,munk gives #f4cd for human and #f4cg for cow milk4#dhf ,sebelien adopts the latter factor1 and ,hammersten nearly the same2 viz41 #f4ci4 ,the weight of authority1 at the present time1 favors a factor considerably above #f4be for calculating the casein and1 in fact1 the total proteids of milk from the weight of nitrogen obtained4 #dhe4 ,bchamp's ,method of ,preparing ,pure ,casein4--,the casein in about one liter of milk is precipitated by adding gradually about three grams of glacial acetic acid diluted with water4 ,the addition of the acid is arrested at the moment when litmus paper shows a slightly acid reaction4 ,the precipitate thus produced1 containing all the casein1 the milk globules and the microzymes1 is separated by filtration1 being washed by decantation before collecting it on the filter4 ,on the filter it is washed with distilled water and the fat removed by shaking with ether4 ,the residue is suspended in water1 dissolved in the least possible quantity of ammonium carbonate1 any insoluble residue 7microzymes1 globules7 separated by filtration and the pure casein thrown out of the filtrate by the addition of acetic acid4 ,the washing with distilled water1 solution in ammonium carbonate1 filtration and reprecipitation are repeated three or four times in order to obtain the casein entirely free of other substances4 ,casein thus prepared is burned to a carbon free ash with difficulty and contains but little over one-tenth per cent of mineral matter4#dhg #dhf4 ,separation of ,casein with ,carbon ,dioxid4--,the supersaturation of the lime compounds of casein with carbon dioxid diminishes the solvent action of the lime and thus helps to throw out the proteid matter4 ,for this reason ,hoppe-,seyler recommends the use of carbon dioxid to promote the precipitation of the casein4#dhh ,the milk is diluted with about twenty volumes of water and treated1 drop by drop1 with very dilute acetic acid as long as a precipitate is formed4 ,a stream of pure carbon dioxid is conducted through the mixture for half an hour1 and it is allowed to remain at rest for twelve hours1 when the casein will have all gone down and the supernatant liquid will be clear4 ,albumins and peptones are not thrown out by this treatment4 ,the method of precipitation is advantageously modified by saturating the diluted milk with carbon dioxid before adding the acetic acid1 less of the latter being required when used in the order just noted4#dhi #dhg4 ,separation of ,albumin4--,in the filtrate from the casein precipitate the albumin may be separated by heating to #hj4 ,it may also be precipitated by tannic acid1 in which case it may contain a little globulin4 ,it may also be thrown out by saturation with ammonium or zinc sulfates4 ,the latter reagent is to be preferred when the nitrogen is to be determined in the precipitate4 ,the quantities of albumin and globulin1 especially the latter1 present in milk are small compared with its content of casein4 #dhh4 ,separation of ,globulin4--,the presence of globulin in milk is demonstrated by ,sebelien in the following manner3#dij ,the milk is saturated with finely powdered common salt and the precipitate produced is separated by filtration4 ,this filtrate in turn is saturated with magnesium sulfate4 ,the precipitate produced by this reagent is collected on a filter1 dissolved in water and precipitated by saturation with sodium chlorid4 ,this process is repeated several times4 ,the final precipitate is proved to be globulin by the following reactions3 ,when a solution of it is dialyzed the proteid body separates as a flocculent precipitate1 which is easily dissolved in a weak solution of common salt4 ,the clear solution thus obtained becomes turbid on adding water1 and more so after the addition of a little acetic acid4 ,a neutral solution of the body is also completely precipitated by saturation with sodium chlorid4 ,these reactions serve to identify the body as a globulin and not an albumin4 ,all the globulin in milk is not obtained by the process1 since a part of it is separated with the casein in the first precipitation4 #dhi4 ,other ,precipitants of ,milk ,proteids4--,many other reagents besides those mentioned have been used for precipitating milk proteids1 wholly or in part4 ,among these may be mentioned the dilute mineral acids1 lactic acid1 rennet1 mercuric iodid in acetic acid1 phosphotungstic acid1 acid mercuric nitrate1 lead acetate and many others4 ,it has been shown by the author that many of these precipitants do not remove all the nitrogen but that among others the mercury salts are effective4#dia ,when nitrogen is to be subsequently determined the acid mercuric nitrate cannot be employed4 #dij4 ,precipitation by ,dialysis4--,since the casein is supposed to be held in solution by the action of salts it is probable that it may be precipitated by removing these salts by dialysis4 #dia4 ,carbohydrates in ,milk4--,the methods of determining lactose in milk1 both by the copper reduction and optical processes1 have been fully set forth in foregoing paragraphs 7#bdc1 #bdd1 #bei1 #bfb74 ,in general1 the optical method by double dilution is to be preferred as practically exact and capable of application with the minimum consumption of time4#dib ,for normal milks a single polarization is entirely sufficient1 making an arbitrary correction for the volume occupied by the precipitated proteids and fat4 ,this correction is conveniently placed at six and a half per cent of the volume of milk employed4 ,the polarimetric estimation of lactose in human milk is likely to give erroneous results by reason of the existence in the serum of polarizing bodies not precipitable by the reagents commonly employed for the removal of proteids4#dic ,the same statement may be made in respect of ass and mare milk4 ,the use of acetopicric acid for removing disturbing bodies1 as proposed by ,thibonet#did does not insure results free from error4 ,with the milks above mentioned1 it is safer to rely on the data obtained by the alkaline copper reagents4 #dib4 ,dextrinoid ,body in ,milk4--,in treating the precipitate1 produced in milk by copper sulfate1 with alcohol and ether for the purpose of removing the fat1 ,ritthausen isolated a dextrin like body quite different from lactose in its properties4#die ,the alcohol ether extract evaporated to dryness leaves a mass not wholly soluble in ether1 and therefore not composed of fat4 ,this residue extracted with ether1 presents flocky particles1 soluble in water and mostly precipitated therefrom by alcohol4 ,this body has a slight reducing effect on alkaline copper salts and produces a gray color with bismuth nitrate4 ,the quantity of this material is so minute as to lead ,ritthausen to observe that it does not sensibly affect the fat determinations when not separated4 ,it is not clearly demonstrated that it is a dextrinoid body and the analyst need not fear that the optical determination of milk sugar will be sensibly affected thereby4 ,raumer and ,spth assume that certain discrepancies1 observed by them in the data obtained for lactose by the copper and optical methods1 are due to the presence of this dextrinoid body1 but no positive proof thereof is adduced4#dif #dic4 ,amyloid ,bodies in ,milk4--,herz has observed in milk a body having some of the characteristics of starch4#dig ,observed by the microscope1 these particles have some of the characteristics of the starch grains of vegetables1 with a diameter of from ten to thirty-five micromillimeters4 ,they are colored blue by iodin4 ,when boiled with water1 however1 these particles differ from starch in not forming a paste4 ,the particles are most abundant in the turbid layer found immediately beneath the ether fat solution in the areometric process of ,soxhlet4 ,the amyloid particles may be collected from cheese and butter by boiling with water1 when they settle and can be observed on the sediment after freeing of fat by ether4 ,some of the statements regarding the adulteration of dairy products with starch may have been made erroneously by reason of the natural occurrence of these particles4 ,as in the case of the dextrin like body mentioned above this starchy substance1 if it really exist1 occurs in too minute a quantity to influence the results of any of the analytical methods heretofore described4 ,in connection with the supposed presence of an amyloid body in milk1 it should be remembered that certain decomposition nitrogenous bodies give practically the same reactions as are noted above4#dih ,among these may be mentioned chitin1 which occurs very extensively in the animal world4 ,the proof of the existence of dextrinoid and amyloid bodies in milk rests on evidence which should be thoroughly revised before being undoubtedly accepted4 ,,analysis ,,of ,,butter4 #did4 ,general ,principles4--,the general analysis of butter fat is conducted in accordance with the methods described in the part of this volume devoted to the examination of fats and oils4 ,the methods of sampling1 drying1 filtering1 and of determining physical and chemical properties1 are there developed in sufficient detail to guide the analyst in all operations of a general nature4 ,there remain for consideration here only the special processes practiced in butter analysis and which are not applied to fats in general4 ,these processes naturally relate to the study of those properties of a distinctive nature1 by means of which butter is differentiated from other fats for which it may be mistaken or with which it may be adulterated4 ,these special studies1 therefore1 are directed chiefly to the consideration of the peculiar physical properties of butter fat1 to its content of volatile acids and to its characteristic forms of crystallization as observed with the aid of the microscope4 ,for dietetic1 economic and legal reasons1 it is highly important that the analyst be able to distinguish a pure butter from any substitute therefor4 #die4 ,appearance of ,melted ,butter4--,fresh1 pure butter1 when slowly melted1 shows after a short time the butter fat completely separated1 of a delicate yellow color and quite transparent4 ,old samples of butter do not give a fat layer of equal transparency4 ,oleomargarin1 or any artificial butter when similarly treated1 gives a fat layer opalescent or opaque4 ,by means of this simple test an easy separation of pure from adulterated butter may be effected4 ,in mixtures1 the degree of turbidity shown by the separated fats may be regarded as a rough index of the amount of adulteration4 ,in conducting the work1 the samples of butter1 in convenient quantities according to the size of the containing vessel1 are placed in beakers and warmed slowly at a temperature not exceeding #ej4 ,after a lapse of half an hour the observations are made4 ,if one part of the melted butter be shaken with two volumes of warm water 7#dj7 and set aside for five minutes the fat is still found as an emulsion1 while oleomargarin1 similarly treated1 shows the fat mostly separated4 ,this process has some merit1 but must not be too highly valued4#dii #dif4 ,microscopic ,examination of ,butter4--,the microscope is helpful in judging the purity of butter and the admixture of foreign fats1 if not in too small quantity to be of any commercial importance1 can easily be detected by this means4#ejj ,the methods of preparing butter fat in a crystalline state are the same as those described in paragraphs #cjg-cji4 ,the crystals of butter fat differ greatly in appearance with the different methods of preparation4 ,when butter is melted1 filtered1 heated to the boiling point of water and slowly cooled1 it forms spheroidal crystalline masses as seen by the microscope1 which present a well defined cross with polarized light4 ,this cross is not peculiar to butter fat1 but is developed therein with greater distinctiveness than in other fats of animal origin4 ,pure1 fresh1 unmelted butter1 when viewed with polarized light through a plate of selenite1 presents a field of vision of uniform tint1 varying with the relative positions of the nicols4 ,when foreign fats1 previously melted1 as in rendering1 are mixed with the butter the crystallization they undergo disturbs this uniformity of tint and the field of vision appears particolored4 ,old1 rancid or melted butter may give rise to the same or similar phenomena under like conditions of examination4 ,the microscope thus becomes a most valuable instrument for sorting butters and in distinguishing them in a preliminary way from oleomargarin4 ,illustration3 ,,fig4 #aab4 ,,thermometer ,,for ,,butyrorefractometer4 #dig4 ,judgment of ,suspected ,butter or ,lard by ,refractive ,power4--,in discriminating between pure and adulterated butters by the aid of the butyrorefractometer 7#cja71 the absolute reading of the instrument is of less importance than the difference which is detected between the highest permissible numbers1 for any degree of temperature1 and the actual reading obtained at that temperature4 ,these differences1 within certain limits1 do not perceptibly vary with the temperature1 and heretofore they have been determined with the aid of a table1 and in this respect the observations have been made the more laborious4 ,wollny has rendered these tables unnecessary by constructing a thermometer in which the mercury column does not indicate degrees of temperature1 but the highest permissible number for butter or lard at the temperature of observation4 ,the scale of the instrument is so adjusted as to include temperatures of from #cj to #dj1 which renders it suited to the examination of butter and lard4 ,the oleothermometer is shown in ,fig4 #aab4 ,the side of the scale ,b is for butter and that marked ,s for lard4 ,the use of the instrument is the simplest possible4 ,the sample of fat is placed in the prisms in the usual manner4 ,when the mercury in the thermometer is at rest1 the scale of the instrument is read4 ,in the case of a butter1 if the reading of the scale give a higher number than that indicated by the thermometer1 the sample is pronounced suspicious and the degree of suspicion is proportional to the difference of the two readings4 #dih4 ,estimation of ,water1 ,fat1 ,casein1 ,ash and ,salt4--,the methods proposed by the author for conducting these determinations1 with minor amendments1 have been adopted by the ,association of ,official ,agricultural ,chemists4#eja ,water4--,the sample held in a flat bottom dish is dried to constant weight at about #ajj4 ,the weight of the sample used should be proportional to the area of the bottom of the dish1 which should be just covered by the film of melted fat4 ,the dish may be previously partly filled with sand1 asbestos or pumice stone4 ,the drying may take place in the air1 in an inert gas or in a vacuum4 ,fat4--,the fat in a sample of butter is readily determined by treating the contents of the dish after the determination of water with an appropriate solvent4 ,the process is conducted as follows3 ,the dry butter from the water determination is dissolved in the dish with ether or petroleum spirit4 ,the contents of the dish are then transferred to a weighed gooch with the aid of a wash bottle containing the solvent1 and washed till free of fat4 ,the crucible and contents are heated at the temperature of boiling water till the weight is constant4 ,the weight of fat is calculated by difference from the data obtained4 ,the fat may also be determined by drying the butter on asbestos or sand1 and subsequently extracting the fat by anhydrous alcohol free ether4 ,the extract1 after evaporation of the ether1 is dried to constant weight at the temperature of boiling water and weighed4 ,casein or ,curd and ,ash4--,the crucible containing the residue from the fat determination is covered and heated1 gently at first1 gradually raising the temperature to just below redness4 ,the cover may then be removed and the heat continued till the contents of the crucible are white4 ,the loss in weight of the crucible and contents represents casein or curd1 and the residue is mineral matter or ash4 ,salt4--,it is the usual custom in the manufacture of butter in this country to add1 as a condiment1 a certain proportion of salt4 ,in ,europe1 the butter offered for consumption is usually unsalted4 ,a convenient method of determining the quantity of salt is found in the removal thereof1 from the sample1 by repeated washing with hot water and in determining the salt in the wash water by precipitation with silver nitrate4 ,the operation is conducted as follows3 ,from five to ten grams of the sample are placed in a separatory funnel1 hot water added1 the stopper inserted and the contents of the funnel well shaken4 ,after standing until the fat has all collected on top of the water1 the stopcock is opened and the water is allowed to run into an erlenmeyer1 being careful to let none of the fat globules pass4 ,hot water is again added to the beaker1 and the extraction is repeated several times1 using each time from ten to twenty cubic centimeters of water4 ,the resulting washings contain all but a mere trace of the sodium chlorid originally present in the butter4 ,the sodium chlorid is determined in the filtrate by a set solution of silver nitrate1 using a few drops of a solution of potassium chromate as an indicator4 ,it is evident that the quantity of salt may also be determined from the ash or mineral matter obtained1 as above noted1 by the same process4 ,if desirable1 which is rarely the case1 the gravimetric method of estimating the silver chlorid may be used4 #dii4 ,volatile or ,soluble ,acids4--,the distinguishing feature of butter1 from a chemical point of view1 is found in its content of volatile or soluble fat acids4 ,among the volatile acids are reckoned those which are carried over in a current of steam at a temperature only slightly higher than that of boiling water4 ,as soluble acids are regarded those which pass without great difficulty into solution in hot water4 ,these two classes are composed essentially of the same acids4 ,of these butyric is the most important1 followed by caproic1 caprylic and capric acids4 ,small quantities or rather traces of acetic1 lauric1 myristic and arachidic acids are also sometimes found in butter4 ,palmitic1 stearic and oleic acids also occur in large quantities4 ,the above named acids1 in combination with glycerol1 form the butter fat4 #ejj4 ,relative ,proportion of ,ingredients4--,the composition of butter fat is given differently by different authorities4#ejb ,a typical dry butter fat may be regarded as having the following composition3 ,per cent4 ,butyrin #g4jj ,caproin1 ,caprylin and ,caprin #b4cj ,olein #cg4gj ,palmitin1 stearin1 etc4 #ec4jj ,pure butter fat consists principally of the above glycerids1 some coloring principles1 varying in quantity and composition with the food of the animal1 and a trace of lecithin1 cholesterol1 phytosterol and a lipochrome4 #eja4 ,estimation of ,volatile or ,soluble ,acids4--,the volatile or soluble acids in butter fat are estimated by the methods already described 7#cdi1 #cea74 ,in practice preference is given to the method of determining volatile acids1 based on the principle that under standard conditions practically all the acids of this nature are secured in a certain volume of the distillate4 ,this assumption is not strictly true1 but the method offers a convenient and reliable manner of obtaining results which1 if not absolute1 are at least comparative4 ,the quantity of acid distilled is determined by titration with tenth normal alkali and for convenience the data are expressed in terms of the volume of the alkali consumed4 ,five grams of normal butter fat will give a distillate1 under the conditions given1 requiring about twenty-eight cubic centimeters of tenth normal alkali for complete saturation4 ,this is known as the reichert-meissl number4 ,occasionally this number may rise to thirty-two or may sink to twenty-five4 ,cases have been reported where it fell below the latter number1 but such samples cannot be regarded as normal butter4 ,the determination of the reichert-meissl number is the most important of the chemical processes applied to butter fat analysis4 #ejb4 ,saponification ,value and ,reichert ,number4--,it may often be convenient to make the same sample of butter fat serve both for the determination of the saponification value and of the reichert number4 ,for this purpose it is convenient to use exactly five grams of the dry filtered fat4 ,the saponification may be accomplished either under pressure or by attaching a reflux condenser to the flask as suggested by ,bremer4#ejc ,when the saponification1 which is accomplished with alcoholic potash lye containing about #a4be grams in each ten cubic centimeters of seventy per cent alcohol1 is finished1 and the contents of the flask are cooled1 the residual alkali is titrated with a set sulfuric acid solution1 using phenolphthalein as indicator4 ,when the color has almost disappeared1 an additional quantity of the indicator is added and the titration continued until the liquid is of an amber tint4 ,a sample of the alkali1 treated as above1 is titrated at the same time and from the two sets of data obtained1 the saponification number is calculated as indicated in paragraph 7#cde74 ,a few drops of the alcoholic lye are added to the contents of the flask and the alcohol removed by evaporation4 ,the residual soap and potassium sulfate are dissolved in #ajj cubic centimeters of recently boiled water1 some pieces of pumice added1 and the volatile acids removed by distillation in the usual way after adding an excess of sulfuric acid4 ,it is important to conduct blank distillations in the same form of apparatus to determine the magnitude of any corrections to be made4 ,the size of the distilling flask and the form of apparatus to prevent mechanical projection of sulfuric acid into the distillate should be the same in all cases4 #ejc4 ,modification of the ,reichert-,meissl ,method4--,kreis has proposed the use of strong sulfuric acid for saponifying the fats1 the saponification and distillation being accomplished in one operation4 ,a source of error of some inconvenience in this method is due to the development of sulfurous acid by the reducing action of the organic matter on the oil of vitriol4 ,pinette proposes to avoid this difficulty by adding1 before the distillation is begun1 sufficient potassium permanganate to produce a permanent red coloration4 ,by this means the sulfurous acid is completely oxidized and its transfer to the standard alkali during distillation entirely prevented4 ,the same result is accomplished by ,micko by the use of potassium bichromate4 ,the details of the manipulation are as follows3#ejd ,about five grams of the fused fat 7butter or oleomargarin7 are placed in a flask of approximately #cjj cubic centimeters capacity4 ,after cooling1 there are added ten cubic centimeters of sulfuric acid containing three grams of water to each ninety-seven grams of the strongest acid4 ,the fat and acid are well mixed by a gentle rotatory motion of the flask and placed in a water bath at a temperature of #ce 7circa7 for fifteen minutes4 ,at the end of this time the flask is removed from the bath and #abe cubic centimeters of water added1 little by little1 keeping the contents cool4 ,next are added four cubic centimeters of a four per cent solution of potassium bichromate4 ,the contents of the flask are vigorously shaken and1 after five minutes1 a solution of ferrous sulfate is added gradually from a burette until the reaction with a drop of potassium ferrocyanid shows a slight excess of the iron salt4 ,the volume of the liquor in the flask is then increased to #aej cubic centimeters by the addition of water and #aaj cubic centimeters distilled4 ,after mixing and filtering through a dry filter1 the acid in #ajj cubic centimeters is determined by standard tenth normal barium hydroxid solution and the number thus obtained increased by one-tenth representing the total acid obtained4 #ejd4 ,elimination of ,sulfurous ,acid4--,prager and ,stern#eje propose to eliminate the sulfurous acid by a stream of air1 succeeded by one of carbon dioxid1 and proceed as follows3 ,five grams of the butter fat are brought into a liter flask1 ten cubic centimeters of strong sulfuric acid are added and the flask is kept for ten minutes at #cj-cb with constant agitation4 ,when the liquid is cold1 air is bubbled through it until the odor of sulfurous acid has disappeared4 ,one hundred cubic centimeters of water are added1 with precautions against rise of temperature1 and carbon dioxid is bubbled through for ten minutes4 ,this is then displaced by a stream of air for another ten minutes1 the delivery tube is washed into the flask with fifty cubic centimeters of water and the distillation is effected4 ,the following results are quoted3 ,cubic centimeters of tenth normal alkali required by five grams of butter fat3 ,reichert-,meissl4 ,prager-,stern4 ,sample a #bi4hf #bi4fj 0 b #cj4bc #bi4fe 0 c #bh4cd #bg4gf 0 d #bh4bj #bh4aj ,the authors do not comment on the possibility of loss of acids other than sulfurous in the stream of air1 but they admit that further investigation is requisite to render the suggestion of ,kreis serviceable4 #eje4 ,errors ,due to ,poor ,glass4--,the easy solubility of the glass holding the reagents is the cause of some of the difficulties attending the determination of the saponification value4 ,the separated silica tends to carry down1 mechanically1 a part of the alkali4 ,this is shown by the fact that after the color has been discharged by titration with acid and the flask set aside a reappearance of the red color is noticed1 after a time1 beginning at the bottom of the flask4#ejf ,in order to avoid difficulties of this nature1 either cold saponification should be practiced or the digestion vessels used for moist combustion in sulfuric acid be employed4 ,errors may also be easily introduced by the use of uncalibrated burettes and from the employment of varying quantities of the phenolphthalein solution4 #ejf4 ,estimation of the ,molecular ,weight of ,butter and ,butter ,substitutes4--,garelli and ,carono have proposed a method for discriminating between butter and its substitutes by the kryoskopic determination of molecular weights4 ,the molecular weights of stearin1 palmitin and olein are #hij1 #hjf and #hhd1 and of butyrin1 caproin and caprylin #cjc1 #chf and #dgj respectively4 ,pure butter1 therefore1 has a lower mean molecular weight than margarin4 ,the method and apparatus of ,beckmann are used in the determination1 fifteen grams of benzol being employed as a solvent4 ,the constant for the molecular depression of the benzol is found to be #ec4 ,the molecular weight obtained with samples of pure butter varied from #fif to #gaf1 and for oleomargarin from #ghj to #hhc4 ,the figures obtained with mixtures of twenty1 twenty-five1 thirty-three and fifty per cent of margarin with butter were #gfa1 #gbj1 #gbh and #gdi respectively4 ,the method can be relied upon to classify samples as follows3 #a4 ,pure butter4 #b4 ,butter containing margarin4 #c4 ,suspicious butter4#ejg #ejg4 ,substitutes and ,adulterants of ,butter4--,in this country1 butter is never adulterated with cocoa or sesame oil1 as is sometimes the case in other lands4 ,the common substitute for butter here is oleomargarin1 and the most common butter adulterant1 neutral lard4 ,the methods of analyses1 by means of which these bodies can be identified1 have already been sufficiently described4 ,by the use of certain digestive ferments and other bodies1 butter may be made to hold an excessive quantity of casein1 sugar and water in the form of a somewhat permanent emulsion4#ejh ,this form of adulteration is revealed at once on melting the sample4 #ejh4 ,furfurol ,reaction with ,sesame ,oil4--,olive oil and sometimes butter are mixed with the cheaper body1 sesame oil4 ,the latter is detected with certainty1 from the red coloration it gives when mixed with furfurol and hydrochloric acid4 ,instead of furfurol1 some body yielding it when subjected to the action of hydrochloric acid1 viz41 sucrose or a pentose sugar1 may be used4 ,it has been found by ,wauters1 however1 that an alcoholic solution of two grams of furfuraldehyd in #ajj cubic centimeters of alcohol is the best reagent4 ,one-tenth of a cubic centimeter of this reagent is used for each test4#eji ,the test is made as follows3 ,the quantity of the furfuraldehyd solution mentioned above is mixed with ten cubic centimeters of hydrochloric acid1 and there are added1 without mixing1 an equal volume of the suspected oil4 ,on standing1 a red coloration is produced at the zone of separation of the two liquids4 ,if the oil be sesame1 the coloration is produced instantly4 ,as little as one per cent of sesame in a mixed oil will show the color in two minutes4 ,the manipulation is also varied by shaking together the reagents and the melted butter4 ,turmeric1 which is sometimes used in coloring butter1 also gives the rose-red color when treated with hydrochloric acid1 but turmeric supplies its own furfuraldehyd4 ,it is easy to distinguish therefore the coloration due to sesame oil1 which is developed only when furfuraldehyd is present1 from that due to the turmeric1 which is produced without the aid of the special reagent4 #eji4 ,butter ,colors4--,where cows are deprived of green food and root crops1 such as carrots1 and kept on a poorly balanced ration1 the butter made from their milk may be almost colorless4 ,to remedy this defect it is quite a common practice to color the product artificially4 ,almost the sole coloring matter used in this country is anatto4#eaj ,other coloring matters which are occasionally employed are turmeric1 saffron1 marigold leaves1 yellow wood 7,chlorophora tinctoria71 carrot juice1 chrome yellow 7lead chromate7 and dinitrocresol4 ,the use of small quantities of anatto1 turmeric or saffron is unobjectionable1 from a sanitary point of view1 but this is not the case with such a substance as lead chromate4 ,the detection of anatto or saffron in butter may be accomplished by the method of ,cornwall4#eaa ,about five grams of the warm filtered fat are dissolved in about fifty cubic centimeters of ordinary ether1 in a wide tube1 and the solution is vigorously shaken for from ten to fifteen seconds1 with from twelve to fifteen cubic centimeters of a very dilute solution of caustic potash or soda in water1 only alkaline enough to give a distinct reaction with turmeric paper1 and to remain alkaline after separating from the ethereal fat solution4 ,the corked tube is set aside1 and in a few hours1 at most1 the greater part of the aqueous solution1 now colored more or less yellow by the anatto1 can be drawn from beneath the ether with a pipette or by a stopcock below1 in a sufficiently clear state to be evaporated to dryness and tested in the usual way with a drop of concentrated sulfuric acid4 ,sometimes it is well to further purify the aqueous solution by shaking it with some fresh ether before evaporating it1 and any fat globules that may float on its surface during evaporation should be removed by touching them with a slip of filter paper2 but the solution should not be filtered1 because the filter paper may retain much of the coloring matter4 ,the dry yellow or slightly orange residue turns blue or violet blue with sulfuric acid1 then quickly green1 and finally brownish or somewhat violet this final change being variable1 according to the purity of the extract4 ,saffron can be extracted in the same way2 it differs from anatto very decidedly1 the most important difference being in the absence of the green coloration4 ,genuine butter1 free from foreign coloring matter1 imparts at most a very pale yellow color to the alkaline solution2 but it is important to note that a mere green coloration of the dry residue on addition of sulfuric acid is not a certain indication of anatto 7as some books state7 because the writer has thus obtained from genuine butter1 free from foreign coloring matter1 a dirty green coloration1 but not preceded by any blue or violet-blue tint4 ,blank tests should be made with the ether4 ,turmeric is easily identified by the brownish to reddish stratum that forms between the ethereal fat solution and the alkaline solution before they are intimately mixed4 ,it may be even better recognized by carefully bringing a feebly alkaline solution of ammonia in alcohol beneath the ethereal fat solution with a pipette1 and gently agitating the two1 so as to mix them partially4 ,another method of separating artificial coloring matter has been proposed by ,martin4#eab ,a method of determining the relative amount of butter color has been worked out by ,babcock4#eac ,,examination ,,of ,,cheese4 #eaj4 ,composition ,of ,cheese4--,pure cheese is made from whole milk by precipitating the casein with rennet4 ,the precipitated casein carries down also the fat of the milk and a little lactose and whey remain incorporated with the cheesy mass4 ,the ingredients of cheese are therefore those of the whole milk less the greater part of the whey1 id est1 milk sugar1 lactalbumin1 globulin1 soluble mineral matters and water4 ,in the conversion of the crude precipitate noted above into the cheese of commerce1 it is subjected to a ripening process which is chiefly conditioned by bacterial action4 ,it is not possible here to enter into a discussion of methods of isolating and identifying the bacteria which promote or retard the ripening process4#ead ,as a rule1 about a month is required for the curing process1 before the cheeses are ready for boxing and shipment4 ,the most important changes during ripening take place in the proteid matter1 which is so altered as to become more palatable and more digestible as a result of the bacterial activity4 ,the percentage composition of the principal cheeses of commerce are shown in the following table3#eae ,water1 ,casein1 ,fat1 ,sugar1 ,ash1 ,per cent4 ,per cent4 ,per cent4 ,per cent4 ,per cent4 ,cheddar #cd4ch #bf4ch #cb4ga #b4ie #c4eh ,cheshire #cb4ei #cb4ea #bf4jf #d4ec #d4ca ,stilton #cj4ce #bh4he #ce4ci #a4ei #c4hc ,brie #ej4ce #ag4ah #be4ab #a4id #e4da ,neufchatel #dd4dg #ad4fj #cc4gj #d4bd #b4ii ,roquefort #ca4bj #bg4fc #cc4af #b4jj #f4ja ,edam #cf4bh #bd4jf #cj4bf #d4fj #d4ij ,swiss #ce4hj #bd4dd #cg4dj #b4cf ,full cream1 #ch4fj #be4ce #cj4be #b4jc #d4jg 7mean of #adc analyses7 ,it is evident that the composition of the cheese will vary with the milk from which it is made and the manipulation to which it is subjected4 ,a good ,american green cheese made from milk of the composition noted below will have the composition which is appended4#eaf ,,table ,,showing ,,mean ,,composition ,,of ,,milk ,,and ,,cheese ,,made ,,therefrom4 ,milk4 ,cheese4 ,per cent4 water #hg4ch #cf4gj 0 0 fat #c4gc #cd4ah 0 0 proteids #c4ac #bc4dd 0 0 sugar1 ash etc4 #e4gf #e4fh ,from the above it is seen that in full milk cheese the ratio of fat to casein is #a4df3 #a1 and to solids not fat #a4ag3 #a4 ,this is a point of some importance in judging the purity of a cheese4 ,when the full milk of a mixed herd is used the percentage of fat in a cheese will always be considerably higher than that of casein4 #eaa4 ,manipulation of the ,milk4--,when sweet milk is received at the cheese factory1 a starter of sour milk is added to it in order to hasten its ripening4 ,when it is thought that the proper degree of acidity has been secured1 it is subjected to a rennet test4 ,in this test #afj cubic centimeters of the milk are heated to #cj and mixed with five cubic centimeters of the rennet solution made by diluting five cubic centimeters of the rennet of commerce with fifty cubic centimeters of water4 ,the number of seconds required for the milk to curdle is noted4 ,the observation is facilitated by distributing throughout the milk a few fine fragments of charcoal4 ,the contents of the vessel are given a circular motion and1 at the moment of setting1 the movement of the black particles is suddenly arrested4 ,if coloring matter be added to the milk1 it should be done before it becomes sour4 ,the quantity of rennet required is determined by the nature of the cheese which it is desired to make4 ,for a cheese to be rapidly cured1 enough rennet should be added to produce coagulation in from fifteen to twenty minutes1 and when slow curing is practiced in from thirty to forty-five minutes4 ,when the mass is solid so that it can be cut with a knife1 the temperature is raised to #cg1 and it is tested on a hot iron until it forms threads an eighth of an inch in length4 ,this test is made by applying an iron heated nearly to redness to the curd4 ,when the curd is in proper condition threads from a few millimeters to two centimeters in length are formed1 when the iron is withdrawn4 ,the longer threads indicate1 but only to a limited extent1 a higher degree of acidity4#eag ,this test is usually made about two and one-half hours from the time of coagulation4 ,the whey is then drawn off through a strainer and the curd is placed on racks with linen bottoms in order that the residual whey may escape1 the curd being stirred meanwhile4 ,in from fifteen to twenty minutes it can be cut into blocks eight or ten inches square and turned over4 ,this is repeated several times in order to facilitate the escape of the whey4 ,when the curd assumes a stringy condition1 it is run through a mill and cut into small bits and is ready for salting1 being cooled to #bg before the salt is added4 ,from two to three pounds of salt are used for each #ajj pounds of curd4 ,the curd is then placed in the molds and pressed into the desired form4 ,the cheeses thus prepared are placed on shelves in the ripening room and the rinds greased4 ,they should be turned and rubbed every day during the ripening1 which takes place at a temperature of from #ae to #ah4eah #eab4 ,official ,methods of ,analysis4--,the methods of cheese analysis recommended by the ,association of ,official ,agricultural ,chemists are provisional and are not binding on its members4 ,they are as follows3#eai ,preparation of ,sample4--,where the cheese can be cut1 a narrow wedge reaching from the edge to the center will more nearly represent the average composition than any other sample4 ,this should be chopped quite fine1 with care to avoid evaporation of water1 and the several portions for analysis taken from the mixed mass4 ,when the sample is obtained with a cheese trier1 a plug perpendicular to the surface one-third of the distance from the edge to the center of the cheese more nearly represents the average composition than any other4 ,the plug should either reach entirely or half way through the cheese4 ,for inspection purposes the rind may be rejected1 but for investigations where the absolute quantity of fat in the cheese is required the rind should be included in the sample4 ,it is well1 when admissible1 to secure two or three plugs on different sides of the cheese1 and1 after splitting them lengthwise with a sharp knife1 use portions of each for the different determinations4 ,determination of ,water4--,from five to ten grams of cheese are placed in thin slices in a weighed platinum or porcelain dish which contains a small quantity of freshly ignited asbestos to absorb the fat4 ,the dish is heated in a water oven for ten hours and weighed2 the loss in weight is considered as water4 ,if preferred1 the dish may be placed in a desiccator over concentrated sulfuric acid and dried to constant weight4 ,in some cases this may require as much as two months4 ,the acid should be renewed when the cheese has become nearly dry4 ,determination of ,ether ,extract4--,grind from five to ten grams of cheese in a small mortar with about twice its weight of anhydrous copper sulfate4 ,the grinding should continue until the cheese is finely pulverized and evenly distributed throughout the mass1 which will have a uniform light blue color4 ,this mixture is transferred to a glass tube having a strong filter paper1 supported by a piece of muslin1 tied over one end4 ,put a little anhydrous copper sulfate into the tube next to the filter before introducing the mixture containing the cheese4 ,on top of the mixture place a tuft of ignited asbestos1 and place the tube in a continuous extraction apparatus and treat with anhydrous ether for fifteen hours4 ,dry the fat obtained at #ajj to constant weight4 ,determination of ,nitrogen4--,the nitrogen is determined by the kjeldahl method1 using about two grams of cheese1 and multiplying the percentage of nitrogen found by #f4be for proteid compounds4 ,determination of ,ash4--,the dry residue from the water determination may be used for the ash determination4 ,if the cheese be rich in fat1 the asbestos will be saturated therewith4 ,this may be carefully ignited and the fat allowed to burn1 the asbestos acting as a wick4 ,no extra heat should be applied during this operation1 as there is danger of spurting4 ,when the flame has died out1 the burning may be completed in a muffle at low redness4 ,when desired1 the salt may be determined in the ash in the manner specified under butter 7#dih74 ,determination of ,other ,constituents4--,the sum of the percentages of the different constituents1 determined as above1 subtracted from #ajj will give the amount of organic acids1 milk sugar etc41 in the cheese4 #eac4 ,process of ,mueller4--,the process of ,mller1#ebj as modified by ,kruger1#eba is conducted as follows3 ,about ten grams of a good average sample of cheese are rubbed in a porcelain mortar with a mixture of three parts of alcohol and one part of ether4 ,after the mixed liquids have been in contact with the cheese five or ten minutes they are poured upon a weighed filter of from fifteen to sixteen centimeters diameter1 and this process is repeated from one to three times1 after which the contents of the mortar are brought upon the filter4 ,the filtrate is received in a weighed flask1 the alcohol ether driven off by evaporation and the residue dried4 ,since it is difficult to get all the particles of cheese free from the mortar1 it is advisable to perform the above process in a weighed dish which can afterwards be washed thoroughly with ether and alcohol and dried and the amount of matter remaining thereon accounted for4 ,the residue remaining in the flask after drying is treated several times with pure warm ether1 and the residue also remaining upon the filter mentioned above is completely extracted with ether4 ,the dried residue obtained in this way from the filter plus the residue in the flask which received the filtrate1 plus the amount left upon the dish in which the cheese was originally rubbed up1 constitute the total dry matter of the cheese freed of fat4 ,all the material soluble in ether should be collected together1 dried and weighed as fat4 ,by this process the cheesy mass is converted into a fine powder which can be easily and completely freed from fat by ether1 and can be dried without becoming a gummy or horny mass4 ,for the estimation of the nitrogen1 about three grams of the well grated cheese are used and the nitrogen determined by moist combustion with sulfuric acid4#ebb ,for the estimation of ash1 about five grams are carbonized1 extracted with water1 and the ash determined as described below4#ebc ,char from two to three grams of the substance and burn to whiteness at the lowest possible red heat4 ,if a white ash cannot be obtained in this manner1 exhaust the charred mass with water1 collect the insoluble residue on a filter1 burn1 add this ash to the residue from the evaporation of the aqueous extract and heat the whole to a low redness till the ash is white4 #ead4 ,separation of ,fat from ,cheese4--,it is often desirable to secure a considerable quantity of the cheese fat for physical and chemical examination without the necessity of effecting a complete quantitive separation4 ,in this laboratory this is accomplished by the method of ,henzold4#ebd ,the cheese1 in quantities of about #cjj grams1 is cut into fragments about the size of a pea and treated with #gjj cubic centimeters of potash lye1 which has previously been brought to a temperature of about #bj4 ,the strength of the lye should be such that about fifty grams of the caustic potash are contained in each liter of the solution4 ,the treatment is conveniently conducted in a wide neck flask and the solution of the casein is promoted by vigorous shaking4 ,after from five to ten minutes1 it will be found that the casein is dissolved and the fat is found swimming upon the surface of the solution in the form of lumps4 ,the lumps of fat are collected in as large a mass as possible by a gentle shaking to and fro4 ,cold water is poured into the flask until the fat is driven up into the neck1 whence it is removed by means of a spoon4 ,the fat obtained in this way is washed a few times with as little cold water as possible in order to remove the residue of potash lye which it may contain4 ,experience shows that the fat by this treatment is not perceptibly attacked by the potash lye4 ,in a short time1 by this procedure1 the fat is practically all separated and is then easily prepared for chemical analysis by filtering and drying in the manner already described 7#bhc74 ,the fat may also be separated1 but with less convenience1 by partially drying the sample1 reducing it to a finely divided state and applying any of the usual solvents4 ,the solvent is removed from the extract by evaporation and the residual fat is filtered and prepared for examination as usual4 #eae4 ,filled ,cheese4--,the skim milk coming from the separators is unfortunately too often used for cheese making4 ,the abstracted fat is replaced with a cheaper one1 usually lard4 ,these spurious cheeses are found in nearly every market and are generally sold as genuine4 ,the purchasers only discover the fraud when the cheese is consumed4 ,many of the ,states have forbidden by statute the manufacture and sale of this fraudulent article4 ,imported cheeses may also be regarded with suspicion1 inasmuch as the method of preparing filled cheese is well known and extensively practiced abroad4 ,a mere determination of the percentage of fat in the sample is not an index of the purity of the cheese4 ,it is necessary to extract the fat by one of the methods already described and1 after drying and filtering1 to submit the suspected fat to a microscopic and chemical examination4 ,a low content of volatile fat acid and the occurrence of crystalline forms foreign to butter will furnish the data for a competent judgment4 ,when the reichert-meissl number falls below twenty-five the sample may be regarded with suspicion4 ,the detection of the characteristic crystals of lard or tallow is reliable corroborating evidence 7#cjh74 ,it is stated by ,khn#ebe that the margarin factory of ,mohr1 at ,bahrenfeld-,altona1 has made for many years a perfect emulsion of fat with skim milk4 ,this product has been much used in the manufacture of filled cheese which is often found upon the ,german market4 #eaf4 ,separation of the ,nitrogenous ,bodies in ,cheese4--,the general methods of separation already described for proteid bodies 7#dag-dbe7 are also applicable to the different nitrogenous bodies present in cheese1 representing the residue of these bodies as originally occurring in the milk1 and also the products which are formed therefrom during the period of ripening4 ,for practical dietary and analytical purposes1 these bodies may be considered in three groups3 7a7 ,the useless 7from a nutrient point of view7 nitrogenous bodies1 including ammonia1 nitric acid1 the phenylamido-propionic acids1 tyrosin1 leucin and other amid bodies4 7b7 ,the albumoses and peptones1 products of fermentation soluble in boiling water4 7c7 ,the caseins and albuminates1 insoluble in boiling water4 ,the group of bodies under 7a71 according to ,stutzer1 may be separated from the groups 7b7 and 7c7 by means of phosphotungstic acid4 ,for this purpose a portion of an intimate mixture of fine sand and cheese 7#ajj cheese1 #djj sand7 corresponding to five grams of cheese1 is shaken for fifteen minutes with #aej cubic centimeters of water4 ,after remaining at rest for another fifteen minutes #ajj cubic centimeters of dilute sulfuric acid 7one acid1 three water7 are added1 followed by treatment with the phosphotungstic acid as long as any precipitate is produced4 ,the mixture is thrown on a filter and the insoluble matters washed with dilute sulfuric acid until the filtrate amounts to half a liter4 ,of this quantity an aliquot part 7#bjj cubic centimeters7 is used for the determination of nitrogen4 ,from the quantity of nitrogen found1 that representing the ammonia1 as determined in a separate portion1 is deducted and the remainder represents the nitrogen present in the cheese as amids4#ebf ,albumoses and ,peptones4--,albumoses and peptones are determined in cheese by the following method3#ebg ,a quantity of the sand mixture already described1 corresponding to five grams of the cheese1 is treated with about #ajj cubic centimeters of water1 heated to boiling1 and the clear liquid above the sand poured into a flask of half a liter capacity4 ,the extraction is continued with successive portions of water in like manner until the volume of the extract is nearly half a liter4 ,when cold1 the volume of the extract is completed to half a liter with water1 the liquor filtered1 #bjj cubic centimeters of the filtrate treated with an equal volume of dilute sulfuric acid 7one to three7 and phosphotungstic acid added until no further precipitate takes place4 ,the nitrogen is determined in the precipitate after filtration and washing with dilute sulfuric acid4 ,casein and ,albuminates4--,the quantity of casein and albuminates in cheese is calculated by subtracting from the total nitrogen that corresponding to ammonia1 amids1 that in the indigestible residue and that corresponding to the albumose and peptone4 ,in three samples of cheese1 viz41 camembert1 swiss1 and gervais1 ,stutzer found the nitrogen1 determined as above1 distributed as follows3#ebh ,camembert4 ,swiss4 ,gervais4 ,n as ammonia #ac4j #c4g #a4f ,n as amids #ch4e #i4j #e4b ,n as albumose peptone #cj4e #h4f #ae4e ,n indigestible #d4j #b4d #h4f ,n as casein1 albuminates #ad4j #gf4c #fi4a ,ammoniacal ,nitrogen4--,the ammoniacal nitrogen is determined by mixing a quantity of the sand-cheese corresponding to five grams of cheese1 with #bjj cubic centimeters of water1 adding an excess of barium carbonate and collecting the ammonia by distillation in the usual way4 ,digestible ,proteids4--,the digestible proteids in cheese are determined by the process of artificial digestion1 which will be described in the part of this volume treating of the nutritive value of foods4 ,these data show the remarkable changes which the proteids undergo where the ripening is carried very far as in the camembert cheese4 #eag4 ,koumiss4--,fermented mare milk has long been a favorite beverage in the ,east1 where it is known as koumiss4 ,in ,europe and this country cow milk is employed in the manufacture of fermented milk1 although it is less rich in lactose than mare milk4 ,the process of manufacture is simple1 provided a suitable starter is at hand4 ,a portion of a previous brewing is the most convenient one1 the fermentation being promoted by the addition of a little yeast4 ,after the process of fermentation is finished the koumiss is placed in bottles and preserved in a horizontal position in a cellar1 where the temperature is not allowed to rise above #ab4 #eah4 ,determination of ,carbon ,dioxid4--,the carbon dioxid in koumiss is conveniently estimated by connecting the bottle by means of a champagne tap with a system of absorption bulbs4#ebi ,the exit tube from the koumiss bottle passes first into an erlenmeyer1 which serves to break and retain any bubbles that pass over4 ,the water is next removed by means of sulfuric acid4 ,the koumiss bottle is placed in a bath of water which is raised to the boiling point as the evolution of the gas is accomplished4 ,the arrangement of the apparatus is shown in ,fig4 #aac4 ,at the end of the operation any residual carbon dioxid in the apparatus is removed by aspiration after removing the tap and connecting it with a soda-lime tube to hold the carbon dioxid in the air4 ,a large balance suited to weighing the koumiss bottle is required for this determination4 ,the carbon dioxid may also be determined1 but less accurately1 by loss of weight in the koumiss bottle after adding weight of water retained in the apparatus4 #eai4 ,acidity4--,although koumiss may contain a trace of acetic acid1 it is best to determine the acid as lactic4 ,the clarification is most easily accomplished by mixing the koumiss with an equal volume of ninety-five per cent alcohol1 shaking and filtering4 ,the first filtrate will usually be found clear4 ,if not it is refiltered4 ,in an aliquot part of the filtrate the acidity is determined by titration with tenth-normal sodium hydroxid solution1 using phenolphthalein as indicator4 ,the necessary corrections for dilution and volume of the precipitated casein are to be made4 ,a linen filter may be used when paper is found too slow4 ,illustration3 ,,fig4 #aac4 ,,apparatus ,,for ,,determining ,,carbon ,,dioxid ,,in ,,koumiss4 #ebj4 ,alcohol4--,half a liter of koumiss1 to which #ajj cubic centimeters of water have been added1 is distilled until the distillate amounts to #ejj cubic centimeters4 ,if the distillate be turbid #ajj cubic centimeters of water are added and the distillation repeated4 ,the alcohol is determined by the processes described hereafter4 #eba4 ,lactose4--,the milk sugar may be determined by any of the methods described1 but most conveniently by double dilution and polarization 7#hf74 #ebb4 ,fat4--,evaporate twenty grams of the sample to dryness and extract with pure ether or petroleum spirit in the manner already described 7#dee74 ,the analysis is more quickly accomplished by the volumetric method of ,babcock or ,gerber 7#dgc-dge74 #ebc4 ,proteids4--,the total proteids are most easily estimated by the official kjeldahl method4#ecj ,the separation of the proteid bodies is accomplished by the methods described in paragraphs #dge-dhi4 ,in addition to the methods already described for separating the soluble and suspended proteid bodies in milk1 and which may be used also for koumiss1 the following should also be mentioned as of especial worth3 ,separation by ,filtration through ,porous ,porcelain4--,a purely physical method1 and one which is to be recommended by reason of the absence of any chemical action upon the different proteid matters1 is that proposed by ,lehmann1 depending upon the principle that when milk is forced through porous porcelain1 the albumin passes through together with the milk1 sugar and other soluble constituents as a clear filtrate1 while the casein and fat are perfectly retained4#eca ,by this method it is quite certain that the albumin and other perfectly soluble proteids of milk may be obtained in the purest form4 ,separation by ,precipitation with ,alum4--,probably the best chemical method of separating the two classes of proteid matters is that proposed by ,schlosmann1 which is effected by means of precipitating the casein with a solution of alum4#ecb ,the principle of this separation rests upon the fact that a solution of potash alum1 when added to milk diluted with four or five times its volume of water1 will completely separate the casein without affecting the albumin or globulin4 ,the operation is conducted as follows3 ,ten cubic centimeters of the milk are diluted with from three to five times that quantity of water and warmed to a temperature of about #dj4 ,one cubic centimeter of a concentrated solution of potash alum is added1 the mixture well stirred and the coagula which are formed allowed to subside4 ,if the coagulation of the casein does not take place promptly1 a small addition of the alum solution is made1 usually not exceeding half a cubic centimeter1 until the precipitation is complete4 ,the temperature during the process should be kept as nearly as possible #dj4 ,after a few minutes1 the mixture is poured upon a filter and the filtrate1 if not perfectly clear1 is poured back until it is secured free of turbidity4 ,in difficult cases the filtration may be promoted by the addition of some common salt or calcium phosphate1 the latter acting mechanically in holding back the fine particles of casein4 ,the precipitate is washed with water at a temperature of #dj1 and afterwards with alcohol1 not allowing the alcohol wash water to flow into the filtrate4 ,when the water has been chiefly removed from the precipitate by washing with alcohol1 the fat of the precipitated casein is removed with ether and the residue used for the determination of nitrogen in the usual way4 ,the albumin is removed from the filtrate by a tannin solution in the manner already described 7#dhj74 ,if it be desired to separate the albumin and globulin1 the methods described in paragraph #cii may be used4 #ebd4 ,mercurial ,method4--,a volumetric method for determining the total proteid matter in milk has lately been proposed by ,deniges4#ecc ,it is based upon the observation that in the precipitation of proteid matter by mercury salts1 a definite quantity of mercury in proportion to the amount of proteid1 is carried down therewith4 ,the precipitation is made with a mercurial salt of known strength and the excess of the mercurial salt in the filtrate is determined by titration4 ,for the details of the manipulation1 the paper cited above may be consulted4 #ebe4 ,water and ,ash4--,from two to five grams of the koumiss are dried to constant weight in a flat platinum dish over ignited sand1 asbestos or pumice stone1 and the dried residue incinerated4 #ebf4 ,composition of ,koumiss4--,the composition of koumiss varies with the character of the milk used and the extent of the fermentation4 ,some of the data obtained by analysts are given below3#ecd ,,composition ,,of ,,koumiss4 ,carbon ,kind ,water1 ,sugar1 ,alcohol1 ,fat1 ,proteid1 dioxid1 ,acidity1 of ,per ,per ,per ,per ,per ,per ,per milk4 cent4 cent4 cent cent4 cent4 cent4 cent4 ,cow #hi4cb #d4ch #j4gf #b4jh #b4ef #j4hc #j4dg ,probably #c4ie #a4ch #j4hh #b4hi #j4hb cow skim'd ,mare #ia4hg #j4gi #b4hi #a4ai #a4ia #a4jd ,from the above it is seen that koumiss is made either from whole or skim milk1 and that the percentage of alcohol may vary within large limits1 its proportion being inverse to that of the milk sugar4 ,koumiss is a beverage which is very palatable1 easily digested and one which is not appreciated in this country in proportion to its merits1 especially for the use of invalids4 ,,authorities ,,cited ,,in ,,part ,,sixth4 #djj ,wiley2 ,proceedings of the ,society for the ,promotion of ,agricultural ,science1 #ahhi1 p4 #hd4 7,omit 8food0 before idiosyncrasy47 #dja ,pharmaceutical ,journal and ,transactions1 ,series #c1 ,vol4 #ah1 p4 #dgi4 #djb ,the ,analyst1 #ahib1 p4 #he4 #djc ,henkel2 ,wiener ,landwirtschaftliche ,zeitung1 #ahhh1 ,s4 #dja3 ,bulletin ,no4 #bd1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #aee4 #djd ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #ce1 ,s4 #cea3 ,bulletin ,no4 #bd1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #aea4 #dje ,baumeister2 ,milch und ,molkerei-,producte1 ,s4 #af4 #djf ,bulletins ,nos4 #i and #be of the ,office of ,experiment ,stations1 ,u4 ,s4 ,department of ,agriculture3 ,farmers' ,bulletins ,nos4 #i and #bi1 ,u4 ,s4 ,department of ,agriculture4 #djg ,annales de ,chimie et de ,physique1 #c;e ,srie1 ,tome #fd1 p4 #fa4 #djh ,bulletin de la ,socit ,chimique de ,paris1 #c ,srie1 ,tome #ae-af1 p4 #bdh4 #dji ,vid4 op4 cit4 supra1 p4 #dec4 #daj ,central-,blatt fr medicinische ,wissenschaft1 ,band #cd1 ,s4 #ade4 #daa ,conn2 ,farmers' ,bulletins #i and #be1 ,office of ,experiment ,stations1 ,u4 ,s4 ,department of ,agriculture3 ,farmers' ,bulletins #i and #bi1 ,department of ,agriculture3 ,les ,microbes et leur ,rle dans la ,laiterie ,freudenreich3 ,langlois1 ,le ,lait1 pp4 #ie et seq4 #dab ,the ,analyst1 ,vol4 #bj1 p4 #aeg4 #dac ,vid4 op4 cit4 supra1 p4 #aeb4 #dad ,forschungs-,berichte ber ,lebensmittel etc41 ,band #b1 ,s4 #cfh4 #dae ,vid4 op4 cit4 supra1 ,band #a1 ,s4 #dbb4 #daf ,vid4 op4 cit4 supra1 ,s4 #cgb4 #dag ,hopkins and ,powers2 ,bulletin ,no4 #dg1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #abg4 #dah ,bulletin ,no4 #ch1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #aah4 #dai ,becke2 ,die ,milchprfungs-,methoden1 ,s4 #de3 ,rouvier2 ,le ,lait1 p4 #de4 #dbj ,the ,analyst1 #ahij1 ,vol4 #af1 p4 #agj4 #dba ,rouvier2 ,le ,lait1 p4 #ce4 #dbb ,central-,blatt fr ,nahrungs und ,genussmittel ,chemie1 ,band #ac1 ,s4 #bgg4 #dbc ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cf4 #dbd ,journal fr ,landwirtschaft1 #ahhb1 ,s4 #bic2 #ahhe1 ,s4 #bea4 #dbe ,vid4 op4 cit4 supra1 #ahgi1 ,s4 #bdi4 #dbf ,forschungen auf dem ,gebiete der ,viehhaltung1 #ahgi1 ,s4 #bfe4 #dbg ,the ,analyst1 ,vol4 #g1 p4 #abi4 #dbh ,vid4 op4 cit4 supra1 ,vol4 #ac1 p4 #bf4 #dbi ,bulletin ,no4 #dg1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #abc4 #dcj ,this work1 ,vol4 #a1 page #daa4 #dca ,bulletin ,no4 #af1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cf4 #dcb ,sixth ,annual ,report ,wisconsin ,agricultural ,experiment ,station1 p4 #fd4 #dcc ,fourth ,annual ,report ,new ,york 7,geneva7 ,agricultural ,experiment ,station1 p4 #bih4 #dcd ,woll2 ,seventh ,annual ,report ,wisconsin ,agricultural ,experiment ,station1 p4 #bch4 #dce ,the ,analyst1 #ahhe1 p4 #df3 ,bulletin ,no4 #ac1 ,part #a1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #hf4 #dcf ,haidlen2 ,die ,milchprfungs-,methoden1 ,s4 #ab4 #dcg ,dingler's polytechnisches ,journal1 ,band #bcb1 ,s4 #dfa4 #dch ,macfarlane2 ,the ,analyst1 ,vol4 #ah1 p4 #gc4 #dci ,duclaux2 ,le ,lait1 p4 #agf4 #ddj ,abraham2 ,the ,analyst1 ,vol4 #i1 p4 #bb4 #dda ,gantter2 ,zeitschrift fr analytische ,chemie1 ,band #bf1 ,s4 #fgg4 #ddb ,morse1 ,piggot and ,burton2 ,american ,chemical ,journal1 ,vol4 #i1 pp4 #ajh and #bbb4 #ddc ,chemiker-,zeitung ,repertorium1 #ahhi1 ,s4 #bbh4 #ddd ,journal de ,pharmacie et de ,chimie1 #ahij1 p4 #dfj4 #dde ,richmond2 ,the ,analyst1 ,vol4 #ag1 p4 #dh3 ,bulletins #bh1 #ca1 #ce1 #ch1 #dc1 and #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture4 #ddf ,bulletin ,no4 #bh1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #ca4 #ddg ,zeitschrift fr analytische ,chemie1 ,band #bg1 ,s4 #dfd4 #ddh ,chemical ,news1 ,nov4 #ahhi4 #ddi ,the ,analyst1 ,vol4 #af1 p4 #fg4 #dej ,vid4 op4 cit4 supra1 ,vol4 #ah1 p4 #ec4 #dea ,vid4 op4 cit4 supra1 ,vol4 #ag1 p4 #ha4 #deb ,chemiker-,zeitung1 ,band #ae1 ,s4 #ahcc4 #dec ,journal of ,analytical ,chemistry1 #ahhh1 ,vol4 #b1 p4 #cga3 ,fifth ,annual ,report ,wisconsin ,agricultural ,experiment ,station4 #ded ,molkerei ,zeitung1 #ahib1 ,no4 #a2 ,chemisches ,central-,blatt1 #ahib1 ,band #b1 ,s4 #dbi4 #dee ,chemiker-,zeitung1 ,band #ah1 ,s4 #ahaf2 ,band #ai1 ,s4 #cdh4 #def ,zeitschrift fr analytische ,chemie1 ,band #cb1 ,s4 #afh4 #deg ,zeitschrift des ,landwirtschaftlichen ,vereins in ,bayern1 #ahhj2 ,zeitschrift fr analytische ,chemie1 ,band #bj1 ,s4 #deb4 #deh ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #ib4 #dei ,instruction sur l',emploi du ,lactobutyrometer1 ,paris1 #ahef et #ahgh3 ,becke2 ,die ,milchprfungs-,methoden1 ,s4 #ff4 #dfj ,bulletin ,no4 #h1 ,iowa ,agricultural ,experiment ,station1 p4 #bie4 #dfa ,dingler's polytechnisches ,journal1 ,band #bfa1 ,s4 #bai4 #dfb ,milch ,zeitung1 ,band #ba1 ,s4 #dif4 #dfc ,op4 cit4 supra1 ,band #bb1 ,s4 #he4 #dfd ,bulletin ,no4 #bd1 ,wisconsin ,agricultural ,experiment ,station4 #dfe ,bulletin ,no4 #ca1 ,wisconsin ,agricultural ,experiment ,station4 #dff ,the ,analyst1 ,vol4 #ag1 p4 #hc4 #dfg ,bulletin ,no4 #ba1 ,vermont ,agricultural ,experiment ,station4 #dfh ,vid4 op4 cit4 #fg1 ,vol4 #ag1 p4 #add2 ,vol4 #ah1 p4 #acj2 ,vol4 #ai1 p4 #fb4 #dfi ,chemiker-,zeitung1 ,band #af1 ,s4 #ahci4 #dgj ,vid4 op4 cit4 supra1 ,band #ai1 ,s4 #cdh2 ,band #ah1 ,s4 #ahaf4 #dga ,vid4 op4 cit4 supra1 ,band #ai1 ,s4 #cdh4 #dgb ,comptes rendus1 ,tome #ajg1 p4 #ggb2 ,hoppe-,seyler's ,handbuch der ,physiologisch- und ,pathologisch-,chemischen ,analyse1 ,s4 #dgi4 #dgc ,proceedings of the ,society for the ,promotion of ,agricultural ,science1 #ahhh1 p4 #ac4 #dgd ,journal of ,physiology1 ,vol4 #aa1 p4 #dei4 #dge ,die ,land wirtschaftlichen ,versuchs-,stationen1 ,band #ca1 ,s4 #aca4 #dgf ,sixth ,annual ,report of the ,wisconsin ,agricultural ,experiment ,station1 p4 #fd4 #dgg ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cf4 #dgh ,zeitschrift fr ,biologie1 ,band #cc1 ,s4 #dc4 #dgi ,journal fr praktische ,chemie1 #b1 ,band #ae1 ,s4 #cbi4 #dhj ,vid4 op4 cit4 #gi1 ,band #cc1 ,neue ,folge1 #ae1 ,s4 #ee4 #dha ,stenberg2 ,zeitschrift fr physiologische ,chemie1 ,band #ac1 ,s4 #ach4 #dhb ,vid4 op4 cit4 supra1 ,s4 #acg4 #dhc ,vid4 op4 cit4 supra1 ,s4 #afj4 #dhd ,journal of the ,american ,chemical ,society1 ,vol4 #ae1 p4 #fdd4 #dhe ,handbuch der ,physiologisch- und ,pathologisch-,chemischen ,analyse1 ,s4 #bhe4 7,read1 ,makris instead of ,makeris47 #dhf ,zeitschrift fr ,biologie1 ,band #bc1 ,s4 #fd4 #dhg ,bulletin de la ,socit ,chimique de ,paris1 #c ,srie1 ,tome #aa1 p4 #aeb4 #dhh ,vid4 op4 cit4 #hf1 ,s4 #dhg4 #dhi ,zeitschrift fr ,nahrungsmittel-,untersuchung1 ,band #aj1 ,s4 #ajd4 #dij ,zeitschrift fr physiologische ,chemie1 ,band #i1 ,s4 #dde4 #dia ,american ,chemical ,journal1 ,vol4 #f1 p4 #bhi4 #dib ,journal of the ,american ,chemical ,society1 ,vol4 #ah1 p4 #dbh4 #dic ,journal de ,pharmacie et de ,chimie1 #f;e ,srie1 ,tome #d1 p4 #fe4 #did ,contribution l'tude des ,lactoses1 ,thse pour le diplme suprieure de ,pharmacie1 ,paris1 #ahib4 7,read ,thibault instead of ,thibonet47 #die ,journal fr praktische ,chemie1 ,neue ,folge1 ,band #ae1 ,s4 #cdh4 #dif ,zeitschrift fr angewandte ,chemie1 #ahif1 ,s4 #gb4 #dig ,chemisches ,central-,blatt1 #ahib1 ,band #b1 ,s4 #ajbh4 #dih ,vid4 op4 cit4 supra1 ,band #ba1 ,s4 #gec4 #dii ,vid4 op4 cit4 #ij1 ,s4 #hf4 #ejj ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 pp4 #bi et seq4 #eja ,vid4 op4 cit4 supra1 pp4 #gc-ge3 ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #bf4 #ejb ,benedikt and ,lewkowitsch2 ,oils1 ,fats and ,waxes1 p4 #dij4 #ejc ,forsuchungs-,berichte ber ,lebensmittel1 #ahie1 ,band #b1 ,s4 #dbd2 ,chemiker-,zeitung ,repertorium1 #ahif1 ,band #bj1 ,s4 #ae4 #ejd ,revue ,internationale des ,falsifications1 ,mai1 #ahic1 p4 #aeg4 #eje ,chemiker-,zeitung1 #ahic1 ,band #ag1 ,s4 #dfh4 #ejf ,zeitschrift fr angewandte ,chemie1 #ahif1 ,s4 #agg4 #ejg ,vid4 op4 cit4 #ij1 ,aug4 #bf1 #ahid1 ,s4 #bai2 ,le ,stazioni ,sperimentali ,agrarie ,italiane1 #ahic1 pp4 #be-gg4 #ejh ,farmers' ,bulletin ,no4 #ab1 ,u4 ,s4 ,department of ,agriculture4 #eji ,bulletin de l',association ,belge des ,chimistes1 ,tome #i1 p4 #bgi4 #eaj ,vid4 op4 cit4 #aja1 p4 #bf4 #eaa ,vid4 op4 cit4 supra1 p4 #bg3 ,chemical ,news1 ,vol4 #ee1 p4 #di4 #eab ,vid4 op4 cit4 #aaa1 p4 #bh4 #eac ,vid4 op4 et4 loc4 cit4 supra4 #ead ,russell2 ,dairy ,bacteriology4 #eae ,woll2 ,dairy ,calendar1 p4 #bbc4 #eaf ,van ,slyke2 ,bulletin #hb1 ,new ,series1 ,new ,york ,agricultural ,experiment ,station1 p4 #fed4 #eag ,babcock2 ,twelfth ,annual ,report ,wisconsin ,agricultural ,experiment ,station1 p4 #acc4 #eah ,woll2 ,dairy ,calendar1 #ahie1 p4 #bbj4 #eai ,bulletin ,no4 #df1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #cg4 #ebj ,landwirtschaftliches ,jahrbuch1 #ahgb1 part #a4 #eba ,molkerei ,zeitung1 #ahic1 ,nos4 #bj1 #bb4 #ebb ,this work1 ,vol4 #b1 p4 #bjd4 #ebc ,vid4 op4 cit4 #abj1 p4 #bd4 #ebd ,milch ,zeitung1 #ahie1 ,band #bd1 ,s4 #gbi3 ,chemiker-,zeitung ,repertorium1 ,band #ai1 ,s4 #cgb4 #ebe ,chemiker-,zeitung1 #ahie1 ,s4 #eed4 #ebf ,zeitschrift fr analytische ,chemie1 ,band #ce1 ,s4 #dig4 #ebg ,vid4 op4 cit4 supra1 ,s4 #dii4 #ebh ,vid4 op4 cit4 supra1 ,s4 #ejb4 #ebi ,bulletin ,no4 #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 pp4 #aah1 #bic4 #ecj ,this work1 ,vol4 #b1 p4 #bjd4 #eca ,pflger's ,archiv1 ,band #ef1 ,s4 #eeh4 #ecb ,hoppe-,seyler's ,zeitschrift fr physiologische ,chemie1 ,band #bb1 ,s4 #bac4 #ecc ,bulletin de la ,socit ,chimique de ,paris1 ,tomes #ae-af1 p4 #aabf4 #ecd ,american ,chemical ,journal1 ,vol4 #h1 p4 #bjj3 ,bulletin #ac1 ,division of ,chemistry1 ,u4 ,s4 ,department of ,agriculture1 p4 #abj4 ,,part ,,seventh4 ,,miscellaneous ,,agricultural ,,products4 #ebg4 ,classification4--,in the preceding parts have been set forth the fundamental principles underlying the conduct of agricultural analysis and a rsum of the best practice of the art4 ,the analyst1 as a rule1 will seldom be required to undertake investigations which are unnoticed in the preceding pages4 ,cases will arise1 however1 in which problems are presented which can not be solved by the rules already elucidated4 ,in respect of the great classes of agricultural bodies1 it will be observed that dairy products have already received special mention4 ,in respect of foods and fodders in general1 it is evident that they are chiefly composed of moisture1 ash1 carbohydrates1 oils and proteid matters4 ,the methods of identifying1 separating and estimating these constituents have been fully set forth4 ,it is not necessary1 therefore1 to study in this part the analytical processes which are applicable to cereals1 cattle foods and other food products1 further than is necessary to present in the most important cases a working rsum of principles and methods4 ,there remain1 however1 certain products of importance which require some special modifications of treatment1 and it is to these that the present part will be chiefly devoted4 ,among these are found tobacco1 tea and coffee1 fruits1 fermented and distilled drinks and certain animal products4 ,it is evident that an enumeration of all agricultural products1 with a description of their methods of examination1 would be impracticable in the available space and undesirable by reason of the repetition which would be required4 ,in each case the analyst1 in possession of the methods described1 will be able to adapt the means at his disposal to the desired purpose to better advantage than any rigid directions could possibly secure4 ,in respect of the analytical methods of determining the nutritive value of foods1 they may be divided into chemical and physiological4 ,the chemical methods embrace the thermal and artificial digestion investigations1 and the physiological include those which are carried out with the help of the animal organisms4 ,in the latter case the digestive process is checked by the analysis of the foods before ingestion and of the excreta of all kinds during and after digestion4 ,it is evident that a detailed description of this method should be looked for in works devoted to physiological chemistry4 ,,cereals ,,and ,,cereal ,,foods4 #ebh4 ,general ,analysis4--,the cereals are prepared for analysis by grinding until the fragments pass a sieve having circular perforations half a millimeter in diameter4 ,the moisture1 ash1 ether extract1 proteids and carbohydrates are determined by some one of the processes already described in detail4 ,in this country the methods of the ,association of ,official ,agricultural ,chemists are generally followed4#ece ,for convenience these methods are summarized below4 ,moisture4--,dry from two to three grams of the fine-ground sample for five hours1 at the temperature of boiling water1 in a current of dry hydrogen4 ,if the substance be held in a glass vessel1 the latter should not be in contact with the boiling water4 ,ash4--,char from two to three grams of the sample and burn to whiteness at the lowest possible red heat4 ,if a white ash can not be obtained in this manner1 exhaust the charred mass with water1 collect the insoluble residue on a filter1 burn it1 add this ash to the residue from the evaporation of the aqueous extract and heat the whole to low redness until the ash is white4 ,ether ,extract4--,pure ether is prepared by washing the commercial article four or five times with water to free it of the chief part of the alcohol it contains4 ,the residual water is mostly removed by treating the liquid with caustic soda or potash4 ,any residual alcohol or water is finally removed by the action of metallic sodium4 ,the ether thus prepared is stoppered1 after the evolution of hydrogen has ceased1 and is kept over metallic sodium4 ,immediately before use it should be distilled out of contact with moist air4 ,the residue from the determination of moisture1 as described above1 is extracted in an appropriate apparatus 7#ci7 with the pure ether for sixteen hours4 ,the extract is dried to constant weight4 ,the weight may be checked by drying and weighing the extraction tube and its contents before and after the operation4 ,crude ,proteids4--,proceed as in the method of determining nitrogen in the absence of nitrates and multiply the weight of nitrogen obtained by #f4be4 ,this factor is a general one1 but should not be rigidly applied4 ,in each instance1 according to the nature of the cereal1 the appropriate factor1 pointed out in paragraph #djg should be used1 and the factor #f4be be applied only in those cases where a special factor is not given4 ,the factors for the common cereals are wheat #e4gj1 rye #e4fb1 oats #f4jf1 maize #f4bb1 barley #e4hb and flaxseed #e4fb4 ,for separating the proteid matters consult paragraphs #cib-daj4 ,in the case of wheat the methods of ,teller may be consulted4#ecf ,amid ,nitrogen4--,the albuminoid nitrogen is determined as directed in paragraph #bjc of volume ,,ii4 ,the difference between this number and that representing the total nitrogen gives the nitrogen as amids4 ,fiber and ,carbohydrates4--,the methods of analysis are described in detail in ,part ,third4 #ebi4 ,bread4--,in general1 the same processes are followed in bread analysis as are used with cereals and flours4 ,in addition to the regular analytical processes1 breads are to be examined for adulterants1 bleaching and coloring matters1 and for the purpose of determining the changes which have taken place in their nutrient constituents in the processes of fermentation and cooking4 ,temperature of ,baking4--,the interior of a loaf during the process of baking does not attain the high temperature commonly supposed4 ,this temperature is rarely found to be more than one degree above the boiling point of water4#ecg ,in biscuits and other thin cakes1 which become practically dry and which by reason of their thinness are the more readily penetrated by heat1 the temperature may go as high as #aaj4 ,soluble ,extract4--,the quantity of matters both in flour and bread1 soluble in cold water1 is determined by extraction in the usual way and drying the extract4 ,soluble albuminoids1 sugars and mineral salts are extracted by this process4 ,when possible1 the operation should be conducted both on the bread and the flour from which it is made4 ,color4--,in baker's parlance is found an apparent contradiction of terms1 since it speaks of bread with 8no color0 when the loaf is dark brown1 while a white loaf is said to have a high color4 ,an ideal color for the interior of a loaf is a light cream tint1 which is more desirable than a pure white4#ech ,the texture1 odor and flavor of the loaf are also to be considered1 but these are properties of more importance to the technical expert than to the analyst4 ,quantity of ,water4--,it is not possible to set a rule of limitation in respect of the quantity of water a bread should hold4 ,for full loaves1 perhaps forty per cent is not too high a maximum1 while some authors put it as low as thirty-four per cent4 ,some flours are capable of holding more water than others1 and the loaf should have just enough water to impart to the slice of bread the requisite degree of softness and the proper texture4 ,most breads will have a content of water ranging from thirty to forty per cent4 ,in biscuits and other thin cakes the moisture is much less in quantity4 ,acidity4--,the acidity of both bread and flour is determined by shaking ten grams of the sample with #bjj cubic centimeters of distilled water for fifteen minutes1 pouring the mass on a filter and titrating an aliquot part of the filtrate with tenth-normal alkali4 ,the acidity is reckoned as lactic acid in the case of breads raised by fermentation4 ,nature of ,nitrogenous ,compounds4--,the methods of investigation are described in paragraphs #cib-daj4 #ecj4 ,determination of ,alum in ,bread4--,the presence of alum in bread may be detected by means of logwood4 ,five grams of fresh logwood chips are digested with #ajj cubic centimeters of amyl alcohol4 ,one cubic centimeter of this decoction and the same quantity of a saturated solution of ammonium carbonate are mixed with ten grams of flour and an equal quantity of water4 ,with pure flour1 a slight pink tint is produced4 ,in the presence of alum the color changes to a lavender or blue1 which is persistent on heating4 ,the test may be varied by diluting five cubic centimeters of the reagents mentioned with ninety cubic centimeters of water and pouring the mixture over ten grams of the crumbled bread4 ,after standing for five minutes1 any residual liquid is poured off and the residue1 washed once with a little water1 is dried in a steam bath1 when the blue color is developed if alum be present4#eci #eca4 ,chemical ,changes ,produced by ,baking4--,changes of a chemical nature1 produced in bread by baking1 are found chiefly in modifications of the starch and proteids4 ,the starch is partly converted into dextrin and the albumins are coagulated4 ,the changes in digestion coefficient are determined by the methods which follow4 ,the fermentations which precede the baking are due to the usual decompositions of the carbohydrates under the influence of yeast germs4 ,,fodders1 ,,grasses ,,and ,,ensilage4 #ecb4 ,general ,principles4--,the analyst1 in examining the fibrous foods of cattle1 is expected to determine moisture1 ash1 fiber and other carbohydrates1 ether extract and albuminoid and amid nitrogen4 ,if a more exhaustive study be required1 the sugar and starch are separated from the other non-nitrogenous matters1 the carbohydrate bodies yielding furfuraldehyd separately determined and the ash subjected to a quantitive analysis4 ,the processes are conducted in harmony with the principles and methods of procedure fully set forth in the preceding pages4 ,green fodders and grasses are easily dried and sampled by comminution in the shredder described on page #i1 and roots by that shown on page #aj4 ,the moisture is determined by drying a small sample of the shredded mass1 while the rest of it is dried1 first at about #fj and finally at #ajj1 or a little above1 ground to a fine powder and subjected to analysis by methods already described4 ,the food values as obtained by analysis should be compared1 when possible1 with those secured by natural and artificial digestion4 ,ensilage is shredded and analyzed in precisely the same way1 but in drying1 the content of volatile acids formed during fermentation must be considered4 ,in other words1 the loss on drying ensilage at #ajj1 or slightly above1 is due not only to the escape of water but also to the volatilization of the acetic acid1 which is one of the final products of fermentation which the mass undergoes in the silo4 #ecc4 ,organic ,acids in ,ensilage4--,in the examination of ensilage1 the organic acids which are present may be determined by the processes described in following paragraphs4 ,the acetic acid1 formed chiefly by fermentation1 is conveniently determined by the method given for tobacco further on4 ,lactic acid is detected and estimated by expressing the juice from a sample of ensilage1 removing the acetic acid by distillation1 repeated once or twice1 and treating the filtered residue with zinc carbonate in excess1 filtering and determining the zinc lactate in the filtrate4 ,the zinc is determined by the method described for evaporated apples and the lactic acid calculated from the weight of zinc found4 ,crystallized zinc lactate contains #ah4ah per cent of water and #bg4bg per cent of zinc oxid4#edj #ecd4 ,changes due to ,fermentation in the ,silo4--,silage differs from green fodder in having less starch and sugar1 more acetic and lactic acids and alcohol and a higher proportion of amid to albuminoid nitrogen4#eda ,there is also a considerable loss of nitrogenous substances in ensilage1 due probably to their conversion into ammonium acetate1 which is lost on drying4 #ece4 ,alcohol in ,ensilage4--,the fermentation which takes place in the silo is not wholly of an alcoholic nature1 as the development of lactic acid1 noted above1 clearly indicates4 ,the alcohol which is formed may escape and but small quantities can be detected in the ripened product4 ,so small is this quantity of alcohol that it appears to be useless to try to secure a quantitive estimation of it4 ,qualitively1 it may be detected by collecting it in a distillate1 which is neutralized or made slightly alkaline with soda or potash lye and redistilled4 ,the greater part of the alcohol will be found in the first few cubic centimeters1 which are made alkaline with potash lye and as much iodin added as can be without giving a red tint to the solution4 ,any alcohol which is present will soon separate as iodoform4 #ecf4 ,comparative ,values of ,fodder and ,ensilage4--,in judging of the comparative values of green and dry fodders for feeding purposes1 it is necessary to secure representative samples in the green1 quickly dried and ensilaged condition4 ,it is quite certain that the greater part of the sugar contained in green fodders is lost both by natural curing and by placing in a silo4 ,when well cured by the usual processes there is but little loss of nitrogenous matters1 but in the silo this loss is of considerable magnitude1 amounting in some instances to as much as thirty per cent4 ,the ideal way of preparing green fodders in order to preserve the maximum food value efficiently1 is to shred them and dry rapidly by artificial heat1 or in the sunlight1 until they are in a condition which insures freedom from fermentation4 ,in this condition1 when placed in bales1 under heavy pressure1 the food constituents are preserved in the highest available form4 ,the immense sugar content of the stalks of maize and sorghum could be preserved in this way almost indefinitely4 ,,flesh ,,products4 #ecg4 ,names ,of ,meats4--,the parts of the animal from which the meats are taken have received distinctive names1 which serve to designate the parts of the carcass offered for sale4 ,these names are not invariable and naturally are quite different in many markets4 ,in this country there is some degree of uniformity among butchers in naming the meats from different parts4 ,the names in scientific use for the parts of mutton1 beef and pork are found in the accompanying illustrations4#edb #ech4 ,sampling4--,when possible the whole animal should constitute the sample4 ,the relative weights of blood1 intestinal organs1 hide1 hoofs1 horns1 bones and edible flesh are determined as accurately as possible4 ,the general method of preparing samples of animal products is given in paragraph #e4 ,illustration3 ,,fig4 #aad4 ,illustration3 ,,fig4 #aae4 ,illustration3 ,,fig4 #aaf4 ,illustration3 ,,names ,,of ,,cuts ,,of ,,meat4 ,the method of sampling employed by ,atwater and ,woods is essentially that just noted4#edc ,the sample1 as received at the laboratory1 is weighed1 the flesh 7edible portion7 is then separated from the refuse 7skin1 bones etc47 and both portions weighed4 ,there is always a slight loss in the separation1 evidently due to evaporation and to small fragments of the tissues that adhere to the hands and to the implements used in preparing the sample4 ,the perfect separation of the flesh from the other tissues is difficult1 but the loss resulting from this is small4 ,in sampling the material for analysis1 it is finely chopped1 either in a tray or in a sausage cutter1 and in each case is well mixed4 #eci4 ,methods of ,analysis4--,the general methods for the analyses of food products are applicable to meats and animal products in general4 ,in the separation of the nitrogenous constituents the methods described in paragraphs #daa-dad are followed4 ,it is not safe to estimate as proteids the total nitrogen multiplied by #f4be1 since the flesh bases have much higher percentages of nitrogen than are found in proteid matters4 ,as indicated in paragraph #bhj the complete extraction of dried meats by ether is difficult of accomplishment4 ,after a few hours it may be assumed that the total extract will represent the fat1 although additional soluble matters are obtained by continuing the process4 ,the heat producing power may be calculated from the analytical data secured4 ,the methods which have been described in the preceding pages will be found sufficient for guidance in the examination of animal products1 and the analyst will find them1 when modified to suit particular cases1 adapted to the isolation and estimation of proximate food principles4 ,the methods of analyses followed by ,atwater and ,woods are given below3#edd ,water and ,water-,free ,substance4--,the drying is done in ordinary water ovens at a temperature of nominally #ajj1 but actually at #if and #ih4 ,for each analysis of animal tissues 7flesh7 one or more samples of from fifty to one hundred grams of the freshly chopped substance are weighed on a small plate1 heated for from twenty-four to forty-eight hours1 cooled1 allowed to stand in the open air for about twenty-four hours1 weighed1 ground1 sifted through a sieve with circular holes one-half millimeter in diameter1 bottled and set aside for analysis4 ,in case of fat samples which cannot be worked through so fine a sieve1 either a coarser sieve is used or the substance crushed as finely as practicable and bottled without sifting4 ,for the complete desiccation1 about two grams of material are dried for three hours4 ,it is extremely difficult to get an absolutely constant weight1 though it is found that this is in most cases approximately attained in four hours4 ,nitrogen1 ,protein1 ,albuminoids etc4--,the nitrogen is determined in the partly dried substance by the method of ,kjeldahl4 ,the protein is calculated by multiplying the percentage of nitrogen by #f4be4 ,the nitrogenous matters in meats and fish1 i4 e41 in the materials which have practically no carbohydrates1 are also estimated by subtracting the sum of ether extract and ash from the water-free substance1 or the sum of water1 ether extract and ash from the fresh substance1 the remainder being taken as proteids1 albuminoids etc41 by difference4 ,while this is not an absolutely correct measure of the total nitrogenous matter1 it is doubtless more nearly so than the product of the nitrogen multiplied by #f4be4 ,fat 7,ether ,extract74--,the fat is extracted with ether in the usual manner4 ,the point at which the extraction is complete is not always easy to determine4 ,for the most part1 the extraction is continued for such time as experience indicates to be sufficient1 and then the flask is replaced by another and the extraction repeated until the new flask shows no increase in weight4 ,according to experience1 the fat of many animal tissues is much more difficult to extract than that of most vegetable substances4 ,in general1 the greater the percentage of fat in a substance the more difficult is the removal of the last traces4 ,dried flesh is frequently so hard that the fineness of the material to be extracted seems to be a very important matter4 ,ash4--,ash is determined by the method recommended by the ,association of ,official ,agricultural ,chemists4 ,food ,value--,potential ,energy4--,the food materials are not necessarily burned in the calorimeter1 but the fuel value of a pound of each of the foods1 as given in the tables1 is obtained by multiplying the number of hundredths of a pound of protein and of carbohydrates by #ah4f and the number of hundredths of a pound of fat by #db4b1 and taking the sum of these three products as the number of calories of potential energy in the materials4 ,more reliable results are obtained by using the factors obtained by ,stohmann2 viz41 #egca calories for proteids1 #iejj calories for common glycerids1 #ibca calories for butter fat1 #cgdf calories for pentose sugars1 #cgdi calories for dextrose and levulose and #ciec calories for sucrose and milk sugar4#ede #edj4 ,further ,examination of ,nitrogenous ,bodies4--,it is evident that both of the methods proposed above for the examination of the nitrogenous constituents of meats are unreliable4 ,if the total nitrogen be determined and multiplied by #f4be the product does not by any means represent the true quantity of nitrogenous matter since the flesh bases contain in some instances more than twenty-five per cent of nitrogen4 ,if1 on the other hand1 the water1 ash and fat in a meat sample be determined and the sum of their per cents be subtracted from #ajj1 the difference represents the nitrogenous bodies plus all undetermined matters and errors of analysis4 ,the assumption that meats are free of carbohydrates is not tenable since glycogen is constantly found therein and in horse flesh in comparatively large amounts4 ,in a thoroughly scientific analysis of meats1 the nitrogenous bodies should be separated and determined by groups1 according to the principles developed in paragraphs #daa-dad4 ,this process requires a great amount of analytical work and in general it will be sufficient to make a cold water extract to secure the flesh bases and a hot water extract to secure the gelatin4 ,the nitrogen is then determined in each of these portions separately4 ,the nitrogen in the cold water extract is multiplied by four1 in the hot water extract by six and in the residue by #f4be4 ,the sum of these products represents approximately the total nitrogenous matter in the sample4 ,aqueous extracts containing nitrogen are easily prepared for moist combustion by placing them in the digestion flasks1 connecting the latter with the vacuum service and evaporating the contents of the flask nearly to dryness4 ,the sulfuric acid is then added and the nitrogen converted into ammonia and determined in the usual manner4 #eda4 ,fractional ,analysis of ,meats4--,a better idea of the composition of a meat is obtained by separating its constituents into several groups by the action of different solvents4 ,this method has been elaborated by ,knorr4#edf ,the separation of the meats in edible portion and waste and the determination of moisture and fat are conducted as already described4 ,the residue from the fat extraction is exhausted with alcohol1 and in the extract are found the nitrogenous bases kreatin1 kreatinin1 sarkin and xanthin1 and urea1 lactic1 butyric1 acetic and formic acids1 glycogen and inosit4 ,in the residue from the alcohol extraction1 the proteid nitrogen is determined in a separate sample4 ,a separate portion of the sample is ground to a fine paste and repeatedly rubbed up with cold water1 which is poured through a tared filter4 ,when the extraction is complete1 the filter and its contents are dried and the dry residue determined4 ,this residue represents the nitrogenous constituents of the muscle fibers and their sheaths together with any other bodies insoluble in cold water4 ,the filtrate from the cold water extraction is heated to boiling to precipitate the albuminous matters which are collected1 dried and weighed1 or the nitrogen therein determined and the albuminous matters calculated by multiplying by the usual factor4 ,the filtrate from the coagulated albuminous bodies is evaporated to dryness and weighed4 ,it consists essentially of the same materials as the alcoholic extract mentioned above4 ,the ash and nitrogen in the aqueous extract are also determined4 ,the mean content of the edible parts of common meats1 expressed as per cents in groups as mentioned1 follow3 ,per cent4 ,water #gc4aa ,ash #a4ah ,total soluble matter #bf4hi ,phosphoric acid #j4di ,per cent4 ,proteids insoluble in cold water #ac4gf ,of which coagulable by heat #b4bd ,cold water extract #c4ef ,ash in water extract #a4ji ,of which phosphoric acid #j4ch ,per cent4 ,fat #d4ic ,alcohol extract #c4jc ,proteids in residue from alcohol #ag4hh ,total nitrogen in sample #c4cg #edb4 ,estimation of ,starch in ,sausages4--,starchy substances are sometimes added to sausages for the purpose of increasing their weight4 ,the presence of starch in a sausage is easily detected by iodin4 ,the quantity may be determined by the following process3#edg ,the principle of the process is based upon the observation that while starch is easily soluble in an aqueous solution of the alkalies1 it is insoluble in an alcoholic solution thereof4 ,the chief constituents of meat1 viz41 fat and proteid matters1 on the other hand1 are readily soluble in an alcoholic solution of potash or soda4 ,this renders the separation of the starch easy4 ,the sample is warmed on a water bath with a considerable excess of an eight per cent solution of potassium hydroxid in alcohol whereby the fat and flesh are quickly dissolved4 ,the starch and other carbohydrate bodies1 remain in an undissolved state4 ,in order to prevent the gelatinizing of the soap which is formed1 the mass is diluted with warm alcohol1 the insoluble residue collected upon a filter and washed with alcohol until the alkaline reaction disappears4 ,the residue is then treated with aqueous potassium hydroxid solution1 whereby the starch is brought into solution and1 after filtration1 is treated with alcohol until it is all precipitated4 ,the precipitated starch is collected upon a filter1 washed with alcohol and finally with ether1 dried and weighed4 ,starch prepared in this way contains a considerable quantity of potash1 the amount of which can be determined by incineration4 ,in order to avoid this trouble1 the starch1 after separation in the first instance as above mentioned and solution in aqueous potassium hydroxid1 is precipitated on the addition of enough acetic to render the solution slightly acid4 ,the precipitated starch1 in this instance1 is practically free of potash1 since potassium acetate is soluble in alcohol4 #edc4 ,detection of ,horse ,flesh4--,since horse flesh has become an important article of human food and is often sold as beef and sausage1 a method of distinguishing it is desirable4 ,the comparative anatomist is able to detect horse flesh when accompanied by its bones1 or in portions sufficiently large for the identification of muscular characteristics4 ,it is well known that horse flesh contains a much higher percentage of glycogen than is found in other edible meats4 ,niebel has based a method of detecting horse flesh upon this fact1 the glycogen being converted into dextrose and determined in the usual way4 ,whenever the percentage of reducing sugars in the dry fat-free flesh exceeds one per cent1 ,niebel infers that the sample under examination is horse flesh4#edh ,the reaction for horse flesh1 proposed by ,brutigam and ,edelmann1 is preferred by ,baumert4 ,in this test about fifty grams of the flesh are boiled for an hour with #bjj cubic centimeters of water1 the filtered bouillon evaporated to about half its volume1 treated with dilute nitric acid and the clear filtrate covered with iodin water4 ,horse flesh1 by reason of its high glycogen content1 produces a burgundy red zone at the points of contact of the two liquids4 ,in the case of sausages1 if starch have been added1 a blue zone is produced1 and if dextrin be present1 a red zone1 both of which obscure the glycogen reaction4 ,the starch is easily removed by treating the bouillon with glacial acetic acid4 ,no method is at present known for separating dextrin from glycogen4 ,the detection of horse flesh is a matter of considerable importance to agriculture as well as to the consumers1 especially of sausages4 ,a considerable quantity of horse flesh is annually sent to the market1 little of which presumably is sold under its own name4 ,as a cheap substitute for beef and pork in sausages1 its use must be regarded as fraudulent1 although no objection can be urged against its sale when offered under its own name4#edi ,,methods ,,of ,,digestion4 #edd4 ,artificial ,digestion4--,the nutrient values of cereals and other foods are determined both by chemical analysis and by digestion experiments4 ,the heat forming properties of foods are disclosed by combustion in a calorimeter1 but the quantity of heat produced is not in every case a guide to the ascertainment of the nutritive value4 ,this is more certainly shown1 especially in the case of proteid bodies1 by the action of the natural digestive ferments4 ,it is probable that the digestion1 which is secured by the action of these ferments without the digestive organs1 is not always the same as the natural process1 but when the conditions which prevail in natural digestion are imitated as closely as possible the effects produced can be considered as approximately those of the alimentary canal in healthy action4 ,three classes of ferments are active in artificial digestion1 viz41 amylolytic ferments1 serving to hydrolyze starch and sugars and to convert them into dextrose1 maltose and levulose1 aliphalytic ferments1 which decompose the glycerids and proteolytic ferments1 which act on the nitrogenous constituents of foods4 ,when these ferments are made to act on foods under proper conditions of acidity and temperature1 artificial digestion ensues1 and by the measurement of the extent of the action an approximate estimate of their digestibility can be secured4 ,in artificial digestion1 the temperature should be kept near that of the body1 viz41 at about #dj4 ,the soluble ferments which are active in the digestion of foods1 as has been intimated1 comprise three great classes4 ,among the first class1 viz41 the amylolytic ferments1 are included not only those which convert starch into dextrose1 but also those which cause the hydrolysis of sugars in general4 ,among these may be mentioned ptyalin1 invertase1 trehalase1 maltase1 lactase1 diastase1 inulase1 pectase and cyto-hydrolytic ferments which act upon the celluloses and other fibers4 ,among the aliphalytic ferments1 in addition to those which act also upon proteid matter1 may be mentioned a special one1 lipase4 ,in the third class of ferments are found pepsin1 trypsin or pancreatin and papain4 ,for the latest information in regard to the nature of the soluble ferments and their nomenclature1 the work of ,bourquelot may be consulted4#eej #ede4 ,amylytic ,ferments4--,a very active ferment of this kind is found in the saliva4 ,saliva may be easily collected from school boys1 who will be found willing to engage in its production if supplied with a chewing gum4 ,a gum free of sugar is to be used1 or if the chewing gum of commerce is employed1 the saliva should not be collected until the sugar has disappeared4 ,a dozen boys with vigorous chewing will soon provide a sufficient quantity of saliva for practical use4 ,the amylolytic digestion is conducted in the apparatus hereinafter described for digestion with pepsin and pancreatin4 ,the starch or sugar in fine powder is mixed with ten parts of water and one part of saliva and kept at about #cg4e for a definite time4 ,the product is then examined for starch1 sucrose1 maltose1 dextrose1 dextrin and levulose by the processes already described4 ,in natural digestion the hydrolysis of the carbohydrates is not completed in the mouth4 ,the action of the ferment is somewhat diminished in the stomach1 but not perhaps until half an hour after eating4 ,the dilute hydrochloric acid in the stomach1 which accumulates some time after eating1 is not active in this hydrolysis4 ,on the contrary the amylolytic ferment of the saliva is somewhat enfeebled by the presence of an acid4 ,the active principle of the saliva is ptyalin4 ,the diastatic hydrolysis of starch has already been described 7#agi74 ,it is best secured at a somewhat higher temperature than that of the human stomach4 #edf4 ,aliphalytic ,ferments4--,in the hydrolysis of glycerids in the process of digestion the fat acids and glycerol are set free4 ,whether the glycerids be completely hydrolyzed before absorption is not definitely known4 ,in certain cases where large quantities of oil have been exhibited for remedial purposes1 the fat acids and soaps have been found in spherical masses in the dejecta#eea and have been mistaken for gall stones4 ,the fat which enters the chyle appears to be mostly unchanged1 except that it is emulsified4#eeb ,the aliphalytic ferment can be prepared from the fresh pancreas1 preferably from animals that have not been fed for forty hours before killing4 ,it is important to prepare the ferment entirely free of any trace of acid4 ,the fresh glands are rubbed to a fine paste with powdered glass and extracted for four days with pure glycerol1 to which one part of one per cent soda solution has been added4 ,the filtered liquor contains aliphalytic1 proteolytic and amylytic ferments1 and is employed for saponification by shaking with the fat to form an emulsion and keeping the mixture1 with occasional shaking1 at a temperature of from #dj to #fj4 ,the free acids can be titrated or separated from the unsaponified fats by solution in alcohol4#eec ,heretofore it has not been possible to separate a pure aliphalytic ferment from any of the digestive glands4 ,the digestion of carbohydrates and that of fats are intimately associated1 and these two classes of foods seem to play nearly the same rle in the animal economy4 ,the aliphalytic ferments1 prepared from the fresh pancreas1 act also on the glucosids and other ester-like carbohydrate bodies4 ,since the fats may be regarded as ethers1 the double action indicates the similarity of composition in the two classes of bodies4#eed ,the aliphalytic ferments exist also in plants and have been isolated from rape seed4#eee #edg4 ,proteolytic ,ferments4--,the most important process in artificial digestion is the one relating to the action of the ferments on proteid matters4 ,the hydrolysis of fats and carbohydrates by natural ferments takes place best in an alkaline medium1 while in the case of proteids when pepsin is used an acid medium is preferred4 ,since the acidity of the stomach is due chiefly to hydrochloric1 that acid is employed in artificial digestion4 ,the hydrolyte used is uniformly the natural ferment of the gastric secretions1 viz41 pepsin2 but this is often followed by the pancreatic ferment1 7pancreatin1 trypsin7 in an alkaline medium4 ,during the digestion1 the proteids are changed into peptones1 and the measurement of this change determines the degree of digestion4 ,the total proteid matter is determined in the sample1 and after the digestion is completed1 the soluble peptones are removed by washing and the residual insoluble proteid matter determined by moist combustion4 ,the difference in the two determinations shows the quantity of proteid matter digested4 ,the investigations of ,khn on the digestion of proteids may be profitably consulted4#eef ,for a summary of digestion experiments in this country the rsum prepared by ,gordon may be consulted4#eeg ,the method followed in this laboratory is fully described by ,bigelow and ,hamilton4#eeh #edh4 ,ferments ,employed4--,both the pepsins of commerce and those prepared directly from the stomachs of pigs may be used4 ,the commercial scale pepsin is found1 as a rule1 entirely satisfactory1 and more uniform results are secured by its use than from pepsin solutions made from time to time from pig stomachs4 ,in the preparation of the pepsin solution one gram of the best scale pepsin is dissolved in one liter of #j4cc per cent hydrochloric acid4 ,two grams of the sample of food products1 in fine powder1 are suspended in #ajj cubic centimeters of the solution and kept1 with frequent shaking1 at a temperature of #dj for twelve hours4 ,the contents of the flask are poured on a wet filter1 the residue on the filter well washed with water not above #dj1 the filter paper and its contents transferred to a kjeldahl flask and the residual nitrogen determined and multiplied by #f4be to get the undigested proteid matter4 ,a large number of digestions can be conducted at once in a bath shown in ,fig4 #aag4eei ,the quantity of water in the bath should be as large as possible4 #edi4 ,digestion in ,pepsin and ,pancreatin4--,the digestion of the proteids is not as a rule wholly accomplished by the stomach juices1 and1 therefore1 in order to secure in artificial digestion results approximating those produced in the living organism1 it is necessary to follow the treatment with pepsin by a similar one with the pancreas juices4 ,the method employed in this laboratory is essentially that of ,stutzer modified by ,wilson4#efj ,illustration3 ,,fig4 #aag4 ,,bath ,,for ,,artificial ,,digestion4 ,the residue from the pepsin digestion1 after washing1 is treated for six hours at near #dj with #ajj cubic centimeters of pancreas solution1 prepared as follows3 ,free the pancreas of a healthy steer of fat1 pass it through a sausage grinder1 rub one kilogram in a mortar with fine sand and allow to stand for a day or longer4 ,add three liters of lime water1 one of glycerol1 of #a4bc specific gravity1 and a little chloroform and set aside for six days4 ,separate the liquor by pressure in a bag and filter it through paper4 ,before using1 mix a quarter of a liter of the filtrate with three-quarters of a liter of water and five grams of dry sodium carbonate1 or its equivalent crystallized1 heat from #ch to #dj for two hours and filter4#efa ,in order to avoid the trouble of preparing the pancreas solution pure active pancreatin may be used4#efb ,one and a half grams of pure pancreatin and three grams of sodium carbonate are dissolved in one liter of water and #ajj cubic centimeters of this solution are used for each two grams of the sample4 ,in all cases where commercial pepsin and pancreatin are used1 their activity should be tested with bodies such as boiled whites of eggs1 whose coefficient of digestibility is well known and those samples be rejected which do not prove to have the required activity4#efc #eej4 ,digestion in ,pancreas ,extract4--,in order to save the time required for successive digestions in pepsin and pancreatin ,niebling has proposed to make the digestion in the pancreas extract alone4#efd ,this process and also a slight modification of it have been used with success by ,bigelow and ,mc,elroy4#efe ,two grams of the sample are washed with ether and placed in a digestion flask with #ajj cubic centimeters of two-tenths per cent hydrochloric acid4 ,the contents of the flask are boiled for fifteen minutes1 cooled1 and made slightly alkaline with sodium carbonate4 ,one hundred cubic centimeters of the unfiltered pancreas solution1 prepared as directed above1 are added and the digestion continued at #dj for six hours4 ,the residue is thrown on a filter1 washed1 and the nitrogen determined4 ,the method is simplified by the substitution of active commercial pancreatin for pancreas extract4 ,the solution of the ferment is made of the same strength as is specified above4 #eea4 ,artificial ,digestion of ,cheese4--,the artificial digestion of cheese is conducted by ,stutzer as follows3#eff ,the digestive liquor is prepared from the fresh stomachs of pigs by cutting them into fine pieces and mixing with five liters of water and #ajj cubic centimeters of hydrochloric acid for each stomach4 ,to prevent decomposition1 two and a half grams of thymol1 previously dissolved in alcohol1 are added to each #fjj cubic centimeters of the mixture4 ,the mixture is allowed to stand for a day with occasional shaking1 poured into a flannel bag and the liquid portion allowed to drain without pressing4 ,the liquor obtained in this way is filtered1 first through coarse and then through fine paper1 and when thus prepared will keep several months without change4 ,it is advisable to determine the content of hydrochloric acid in the liquor by titration and this content should be two-tenths of a per cent4 ,the cheese to be digested is mixed with sand as previously described1 freed of fat by extraction with ether1 and a quantity corresponding to five grams of cheese placed in a beaker1 covered with half a liter of the digestive liquor and kept at a temperature of #dj for forty-eight hours4 ,at intervals of two hours the flasks are well shaken and five cubic centimeters of a ten per cent solution of hydrochloric acid added and this treatment continued until the quantity of hydrochloric acid amounts to one per cent4 ,after the digestion is finished1 the contents of the beaker are thrown on a filter1 washed with water and the nitrogen determined in the usual way in the residue4 ,by allowing the pepsin solution to act for two days as described above1 the subsequent digestion with pancreas solution is superfluous4 #eeb4 ,suggestions ,regarding ,manipulation4--,the filter papers should be as quick working as possible to secure the separation of all undissolved particles4 ,they should be of sufficient size to hold the whole contents of the digestion flask at once1 since if allowed to become empty and partially dry1 filtration is greatly impeded4 ,the residue should be dried at once if not submitted immediately to moist combustion4 ,after drying1 the determination of the nitrogen can be made at any convenient time4 ,beaker flasks1 i4 e41 lip erlenmeyers with a wide mouth are most convenient for holding the materials during digestion4 ,the flasks are most conveniently held by a crossed rubber band attached at either end to pins in the wooden slats extending across the digestive bath4 ,the bath should be suspended by cords from supports on the ceiling and a gentle rotatory motion imparted to it resembling the peristaltic action attending natural digestion4 #eec4 ,natural ,digestion4--,the digestion of foods by natural processes is determined chiefly by the classes of ferments already noted4 ,the principle underlying digestive experiments with the animal organism may be stated as follows3 ,a given weight of food of known composition is fed to a healthy animal under the conditions of careful control and preparation already mentioned4 ,the solid dejecta of the animal during a given period are collected and weighed daily1 being received directly from the animal in an appropriate bag1 safely secured1 as is shown in the accompanying figure4 ,the dejecta are weighed1 dried1 ground to a fine powder1 mixed and a representative part analyzed4 ,the difference between the solid bodies in the dejecta and those given in the food during the period of experiment represents those nutrients which have been digested and absorbed during the passage of the food through the alimentary canal4 ,the urine1 containing solid bodies representing the waste of the animal organism1 does not require to be analyzed for the simple control of digestive activity outlined above4 ,in a complete determination of this kind the exhalations from the surface of the body and from the lungs are also determined4 ,in the latter case the human animal is selected for the experiment2 in the former it is more convenient to employ the lower animals1 such as the sheep and cow4 ,the arrangement of the stalls and of the apparatus for collecting the excreta should be such as is both convenient and effective4#efg ,the method of constructing a bag for attachment to a sheep is shown in ,fig4 #aah4 ,it is made according to the directions given by ,gay1 of heavy cloth and in such a way as to fit closely the posterior parts of the animal4#efh ,when attached1 its appearance is shown in ,fig4 #aai4 ,illustration3 ,,fig4 #aah4--;,,bag ,,for ,,collecting ,,feces4 ,illustration3 ,,fig4 #aai4--;,,fecal ,,bag ,,attachment4 ,healthy animals in the prime of life are used1 and the feeding experiments are conducted with as large a number of animals as possible1 in order to eliminate the effects of idiosyncrasy4 ,the food used is previously prepared in abundant quantity and its composition determined by the analysis of an average sample4 ,the feeding period is divided into two parts4 ,in the first part the animal is fed for a few days with the selected food until it is certain that all the excreta are derived from the nutrients used4 ,in the second part the same food is continued and the excreta collected1 weighed1 the moisture determined1 and the total weight of the water-free excreta ascertained4 ,the first part should be of at least seven and the second of at least five days duration4 ,the urine and dung are analyzed separately4 ,males are preferred for the digestion experiments because of the greater ease of collecting the urine and feces without mixing4 ,for ordinary purposes the feces only are collected4 ,the methods of analysis do not differ from those described for the determination of the usual ingredients of a food4 ,example4--,the following data taken from the results of digestive experiments1 obtained at the ,maine ,station1 will illustrate the method of comparing the composition of the food with that of the feces and of determining the degree of digestion which the proteids and other constituents of the food have undergone4 ,,composition ,,of ,,maize ,,fodder ,,and ,,of ,,feces ,,therefrom ,,after ,,feeding ,,to ,,sheep4 ,,before ,,drying4 ,water1 ,ash1 ,proteid1 ,fiber1 ,fat1 ,undetermined1 per per per per per per ,food4 cent4 cent4 cent4 cent4 cent4 cent4 ,sweet maize #hc4he #a4ac #b4ah #d4ad #j4fb #h4jh ,feces #gb4ja 444 444 444 444 444 ,,dry4 ,ash1 ,proteid1 ,fiber1 ,fat1 ,undetermined1 per per per per per ,food4 cent4 cent4 cent4 cent4 cent4 ,sweet maize #g4ja #ac4eb #be4fc #c4hf #di4ih ,feces #ad4db #ag4eb #ai4cd #b4fh #df4jd ,,daily ,,weights4 ,green1 ,dry1 ,food4 grams4 grams4 ,sweet maize #beba #djg ,feces #dde #abe ,,per ,,cent ,,digested4 ,food4 ,ash1 ,proteid1 ,fiber1 ,undetermined1 ,fat1 ,sweet maize #cg4j #fj4b #gf4i #ga4h #gh4c ,in the above instance it is seen that the coefficient of digestibility extended from #cg4j per cent in the case of the mineral components of the food1 to #gh4c per cent in the case of the fats4 ,these data are taken only from the results obtained from a single sheep and one article of food4 ,the mean data secured from two animals and three kinds of maize fodder show the following per cents of digestibility3 ,ash #ci4d1 proteid #fa4h1 fiber #gf4g1 undetermined matters #gb4a1 fat #gf4d4 ,the undetermined matters are those usually known as nitrogen free extract and composed chiefly of pentosans and other carbohydrates4#efi #eed4 ,natural ,digestibility of ,pentosans4--,the digestibility of pentosan bodies in foods under the influence of natural ferments has been investigated by ,lindsey and ,holland4#egj ,the feeding and collection of the feces is carried on as described above and the relative proportions of pentosan bodies in the foods and feces determined by estimating the furfuraldehyd as prescribed in paragraph #aej4ega ,,preserved ,,meats4 #eee4 ,methods of ,examination4--,in general the methods of examination are the same as those applied in the study of fresh meats4 ,the contents of water1 salt and other preservatives1 fat and nitrogenous matters are of most importance4 ,when not already in a fine state1 the preserved meats are run through meat cutters until reduced to a fine pulp4 ,most potted meats are already in a state of subdivision well suited to analytical work4 ,the composition of preserved meats has been thoroughly studied in this laboratory by ,davis4#egb #eef4 ,estimation ,of ,fat4--,attention has already been called to the difficulty of extracting the fat from meats by ether or other solvents4#egc ,in preserved meats1 as well as in fresh1 it is preferable to adopt some method which will permit of the decomposition of the other organic matters and the separation of the fat in a free state4 ,the most promising methods are those employed in milk analyses for the solution of nitrogenous matters4 ,sulfuric or hydrochloric acid may be used for this purpose1 preference being given to sulfuric4 ,the separated fats may be taken up with ether or separated by centrifugal action4 ,a method of this kind for preserved meats1 suggested by ,hefelmann1 is described below4 ,about six grams of the moist preserved meat are placed in a calibrated test tube and dissolved in twenty-five cubic centimeters of fuming hydrochloric acid4 ,the tube is placed in a water bath1 quickly heated to boiling and kept at that temperature for half an hour4 ,about twenty cubic centimeters of cold water are added and the temperature lowered to #cj1 then twenty cubic centimeters of ether and the tube gently shaken to promote the solution of the fat4 ,when the ether layer has separated1 its volume is read and an aliquot part removed by means of a pipette1 dried and weighed4 ,the separation of the ethereal solution is greatly promoted by whirling4 ,the mean proportions of the ingredients of preserved meats are about as follows3 ,per cent4 ,water #fg4j ,dry matter #cc4j ,of which ,nitrogenous bodies #ai4j ,fats #aj4e ,ash and undetermined #c4e #eeg4 ,meat ,preservatives4--,various bodies are used to give taste and color to preserved meats and to preserve them from fermentation4 ,the most important of these bodies are common salt1 potassium and sodium nitrates1 sulfurous1 boric1 benzoic and salicylic acids1 formaldehyd1 saccharin and hydronaphthol4 ,a thorough study of the methods of detecting and isolating these bodies has been made in this laboratory by ,davis and the results are yet to be published as a part of ,bulletin #ac4 ,,determination ,,of ,,nutritive ,,values4 #eeh4 ,nutritive ,value of ,foods4--,the value of a food as a nutrient depends on the amount of heat it gives on combustion in the tissues of the body1 i4 e4 oxidation1 and in its fitness to nourish the tissues of the body1 to promote growth and repair waste4 ,the foods which supply heat to the body are organic in their nature and are typically represented by fats and carbohydrates4 ,the foods which promote growth and supply waste are not only those which preeminently supply heat1 but also include the inorganic bodies and organic nitrogenous matters represented typically by the proteids4 ,it is not proper to say that one class of food is definitely devoted to heat forming and another to tissue building1 inasmuch as the same substance may play an important rle in both directions4 ,as heat formers1 carbohydrates and proteids have an almost equal value1 as measured by combustion in oxygen1 while fat has a double value for this purpose4 ,the assumption that combustion in oxygen forms a just criterion for determining the value of a food must not be taken too literally4 ,there are only a few bodies of the vast number which burn in oxygen that are capable of assimilation and oxidation by the animal organism4 ,only those parts of the food that become soluble and assimilable under the action of the digestive ferments1 take part in nutrition and the percentage of food materials digested varies within wide limits but rarely approaches #ajj4 ,it may be safely said that less than two-thirds of the total food materials ingested are dissolved1 absorbed1 decomposed and assimilated in the animal system4 ,we have no means of knowing how far the decomposition 7oxidation7 extends before assimilation1 and therefore no theoretical means of calculating the quantity of heat which is produced during the progress of digestion4 ,the vital thermostat is far more delicate than any mechanical contrivance for regulating temperature and the quantity of food1 in a state of health1 converted into heat1 is just sufficient to maintain the temperature of the body at a normal degree4 ,any excess of heat produced1 as by violent muscular exertion1 is dissipated through the lungs1 the perspiration and other secretions of the body4 ,pure cellulose or undigestible fiber1 when burned in oxygen1 will give a thermal value approximating that of sugar1 but no illustration is required to show that when taken into the system the bodily heat afforded by it is insignificant in quantity4 ,thermal values1 therefore1 have little comparative usefulness in determining nutritive worth1 except when applied to foods of approximately the same digestive coefficient4 #eei4 ,comparative ,value of ,food ,constituents4--,it has already been noted that1 judged by combustion in oxygen1 carbohydrates and proteids have about half the thermal value possessed by fats4 ,commercially1 the values of foods depend in a far greater degree on their flavor and cooking qualities than upon the amount of nutrition they contain4 ,butter fat1 which is scarcely more nutritious than tallow1 is worth twice as much in the market1 while the prices paid for vegetables and fruits are not based to any great extent on their food properties4#egd ,in cereals1 especially in wheat1 the quantity of fat is relatively small1 and starch is the preponderating element4 ,in meats1 carbohydrates are practically eliminated and fats and proteids are the predominating constituents4 ,in the markets1 fats and proteids command far higher prices than sugars and starches4 ,the relative commercial food value of a cereal may be roughly approximated by multiplying the percentages of fat and protein by two and a half and adding the products to the percentage of carbohydrates less insoluble fiber4 ,this method was adopted in valuing the cereals at the ,world's ,columbian ,exposition4#ege #efj4 ,nutritive ,ratio4--,in solid foods the nutritive ratio is that existing between the percentage of proteids and that of carbohydrates1 increased by multiplying the fat by two and a half and adding the product4 ,in a cereal containing twelve per cent of protein1 seventy-two of carbohydrates1 exclusive of fiber1 and three of fat1 the ratio is #ab3 #gb #c #b4e #f4e4 ,instead of calculating the nutritive ratio directly from the data obtained by analysis1 it may be reckoned from the per cents of the three substances in the sample multiplied by their digestive coefficient4 ,since the relative amounts of proteids1 fats and carbohydrates digested do not greatly differ1 the numerical expression of the nutritive ratio is nearly the same when obtained by each of these methods of calculation4 ,where the proportion of protein is relatively large the ratio is called narrow1 #a3 #d 444 #f4 ,when the proportion of protein is relatively small the ratio is called broad #a3 #h 444 #ab4 ,in feeding1 the nutritive ratio is varied in harmony with the purpose in view1 a narrow ratio favoring the development of muscular energy1 and a wide one promoting the deposition of fat and the development of heat4 ,these principles guide the scientific farmer in mixing rations for his stock1 the work horses receiving a comparatively narrow and the beeves a relatively wide ratio in their food4 #efa4 ,calorimetric ,analyses of ,foods4--,the general principles of calorimetry have been already noticed4 ,the theoretical and chemical relations of calorimetry have been fully discussed by ,berthelot1 ,thomsen1 ,ostwald and ,muir4#egf ,in the analyses of foods the values as determined by calculation or combustion are of importance in determining the nutritive relations4 ,atwater has presented a rsum of the history and importance of the calorimetric investigations of foods to which the analyst is referred4#egg ,in the computation of food values the percentages of proteids1 carbohydrates and fats are determined and the required data obtained by applying the factors #dajj1 #eejj and #icjj calories for one gram of carbohydrates1 proteids and fats respectively4 ,for most purposes the computed values are sufficient1 but it is well to check them from time to time by actual combustions in a calorimeter4 #efb4 ,combustion in ,oxygen4--,the author made a series of combustions of carbonaceous materials in oxygen at the laboratory of ,purdue ,university in #ahgg1 the ignition being secured by a platinum wire rendered incandescent by the electric current4 ,the data obtained were unsatisfactory on account of the crudeness of the apparatus4 ,the discovery of the process of burning the samples in oxygen at a high pressure has made it possible to get expressions of thermal data which while not yet perfect1 possess a working degree of accuracy4 ,the best form of bomb calorimeter heretofore employed is that of ,hempel1 as modified by ,atwater and ,woods4#egh ,a section of this calorimeter1 with all the parts in place1 is shown in ,fig4 #abj4 ,in the figure the steel cylinder ,a1 about #ab4e centimeters deep and #f4b in diameter1 represents the chamber in which the combustion takes place4 ,its walls are about half a centimeter thick and it weighs about three kilograms4 ,it is closed1 when all the parts are ready and the sample in place1 by the collar ,c1 which is secured gas tight by means of a powerful spanner4 ,the cover is provided with a neck ,d carrying a screw ,e and a valve screw ,f4 ,in the neck ,d1 where the bottom of the cylinder screw ,e rests1 is a shoulder fitted with a lead washer4 ,through ,g the oxygen used for combustion is introduced4 ,the upper edge of the cylinder ,a is beveled and fits into a groove in the cover ,b1 carrying a soft metal washer4 ,to facilitate the screwing on of the cover1 ball bearings ,,kk1 made of hard steel1 are introduced between the collar and the cover4 ,the platinum wires ,h and ,i support the platinum crucible holding the combustible bodies which are ignited by raising the spiral iron wire connecting them to the temperature of fusion by an electric current4 ,the combustion apparatus when charged is immersed in a metal cylinder ,m1 containing water and resting on small cylinders of cork4 ,the water is stirred by the apparatus ,,ll4 ,the cylinder ,m is contained in two large concentric cylinders1 ,n1 ,o1 made of non-conducting materials and covered with disks of hard rubber4 ,the space between ,o and ,n may be filled with water4 ,the temperature is measured by the thermometer ,p1 graduated to hundredths of a degree and the reading is best accomplished by means of a cathetometer4 ,illustration3 ,,fig4 #abj4 ,,hempel ,,and ,,atwater',s ,,calorimeter4 #efc4 ,the ,williams ,calorimeter4--,the calorimeter bomb has been improved by ,williams by making it of aluminum bronze of a spheroidal shape4 ,the interior of the bomb is plated with gold4 ,by an ingenious arrangement of contacts the firing is secured by means of a permanently insulated electrode fixed in the side of the bomb4 ,the calorimetric water1 as well as that in the insulating vessel1 is stirred by means of an electrical screw so regulated as to produce no appreciable degree of heat mechanically4 ,the combustion is started by fusing a fine platinum wire of definite length and thickness by means of an electric current4 ,the heat value of this fusion is determined and the calories produced deducted from the total calories of the combustion4 ,the valve admitting the oxygen is sealed automatically on breaking connection with the oxygen cylinder4 ,the effluent gases1 at the end of the combustion1 may be withdrawn through an alkaline solution and any nitric acid therein thus be fixed and determined4#egi #efd4 ,manipulation and ,calculation4--,the material to be burned is conveniently prepared by pressing it into tablets4 ,the oxygen is supplied from cylinders1 of which two should be used1 one at a pressure of more than twenty atmospheres4 ,by this arrangement a pump is not required4 ,in practical use1 a known weight of the substance to be burned is placed in the platinum capsule1 the cover of the bomb screwed on1 after all adjustments have been made1 and the apparatus immersed in the water contained in ,m1 which should be about #b below room temperature4 ,all the covers are placed in position and the temperature1 of the water in ,m begins to rise4 ,readings of the thermometer are taken at intervals of about one minute for six minutes1 at which time the temperature of the bomb and calorimetric water may be regarded as sensibly the same4 ,the electric current is turned on1 the iron wire at once melts1 ignites the substance and the combustion rapidly takes place4 ,in the case of bodies which do not burn readily ,atwater adds to them some naphthalene1 the thermal value of which is previously determined4 ,the calories due to the combustion of the added naphthalene are deducted from the total calories obtained4 ,the temperature of the water in ,m rises rapidly at first1 and readings are made at intervals of one minute for five minutes1 and then again after ten minutes4 ,the first of the initial readings1 the one at the moment of turning on the current1 and the last one mentioned above are the data from which the correction1 made necessary by the influence of the temperature of the room1 is calculated by the following formulas4#ehj ,the preliminary readings of the thermometer at one minute intervals are represented by t1 t1 t 444 t4 ,the last observation t is taken as the beginning temperature of the combustion and is represented in the formulas for calculations by 4 ,the readings after combustion are also made at intervals of one minute1 and are designated by 1 444 4 ,the readings are continued until there is no observed change between the last two4 ,generally this is secured by five or six readings4 ,the third period of observations begins with the last reading 1 which in the next series is represented by t1 t 444 t4 ,in order to make the formulas less cumbersome let t - t ------------ v1 n - #a t - t ------------- v1 n - #a t t t 444 t --------------------------- t1 n t t t 444 t and -------------------------------- t4 n ,the correction to be made to the difference between - for the influence of the outside temperature is determined by the formula of ,regnault-,pfaundler1 which is as follows3 v - v t -------------- 7 r -------- - nt7 - 7n - #a7v1 t - t #b in which r is calculated from the observation of the thermometer 1 etc41 made immediately after the combustion4 ,it is equal to the sum of observations 1 etc41 increased by an arbitrary factor equivalent to 7 - 7_/#i1 which is made necessary by reason of the irregularity of the temperature increase during the first minute after combustion1 the mean temperature during that minute being somewhat higher than the mean of the temperatures at the commencement and end of that time4 ,the quantity of heat formed by the combustion of the iron wire used for igniting the sample is to be deducted from the total heat produced4 ,this correction may be determined once for all1 the weight of the iron wire used being noted and that of any unburned portion being ascertained after the combustion4 ,ten milligrams of iron1 on complete combustion1 will give sixteen calories4 ,in the combustion of substances containing nitrogen1 or in case the free nitrogen of the air be not wholly expelled from the apparatus before the burning1 nitric acid is formed which is dissolved by the water produced4 ,the heat produced by the solution of nitric acid in water is #ad4c calories per gram molecule4 ,the quantity of nitric acid formed is determined by titration and a corresponding reduction made in the total calculated calories4 ,in the titration of nitric acid it is advisable to make use of an alkaline solution1 of which one liter is equivalent to #d4djf grams of nitric acid4 ,one cubic centimeter of the reagent is equivalent to a quantity of nitric acid represented by one calorie4 ,since the materials of which the bomb is composed have a specific heat different from that of water1 it is necessary to compute the water thermal value of each apparatus4 ,the hydrothermal equivalent of the whole apparatus is most simply determined by immersing it at a given temperature in water of a different temperature4#eha ,with small apparatus this method is quite sufficient1 but there are many difficulties attending its application to large systems weighing several kilograms4 ,in these cases the hydrothermal equivalent may be calculated from the specific heats of the various components of the apparatus4 ,in calculating these values the specific heats of the various components of the apparatus are as follows3 ,brass #j4jic ,steel #j4ajig ,platinum #j4jcbd ,copper #j4jibde ,lead #j4jcae ,oxygen #j4bchi ,glass #j4aij ,mercury #j4jccb ,hard rubber #j4ccabe ,example4--,it is required to calculate the hydrothermal value of a calorimeter composed of the following substances3 ,hydrothermal value4 ,steel bomb and cover1 #bhej grams #j4ajig #cab4fe grams4 ,platinum lining1 capsule and wires1 #abj grams #j4jcbd #c4hi 0 ,lead washer1 #ajj grams #j4jcae #c4ae 0 ,brass outer cylinder1 #ejj grams #j4jic #df4ej 0 ,mercury in thermometer1 #aj grams #j4jccb #j4cc 0 ,glass 7part of thermometer in water71 #aj grams #j4ai #a4ij 0 ,brass stirring apparatus 7part in water71 #ajj grams #j4jic #i4cj 0 ------ ,total water value of system #cgg4gb 0 ,when a bomb of #cjj cubic centimeters capacity is filled with oxygen at a pressure of twenty-four atmospheres it will hold about ten grams of the gas1 equivalent to a water value of #b4dj grams4 ,hence the water value of the above system when charged1 assuming the bomb to be of the capacity mentioned1 is #chj4ab grams4 ,if the cylinder holding the water be made of fiber or other non-conducting substance1 its specific heat is best determined by filling it in a known temperature with water at a definite different temperature4 ,it is advisable to have the water cylinder of such a size as to permit the use of a quantity of water for the total immersion of the bomb which will weigh1 with the water value of the apparatus1 an even number of grams4 ,in the case above1 #bfbb4bh grams of water placed in the cylinder will make a water value of #c1jjj grams1 which is one quite convenient for calculation4 #efe4 ,computing the ,calories of ,combustion4--,in the preceding paragraph has been given a brief account of the construction of the calorimeter and of the methods of standardizing it and securing the necessary corrections in the data directly obtained in its use4 ,an illustration of the details of computing the calories of combustion taken from the paper of ,stohmann1 ,kleber and ,langbein1 will be a sufficient guide for the analyst in conducting the combustion and in the use of the data obtained4#ehb ,weight of substance burned1 #a4jg grams4 ,water value of system 7water apparatus71 #b1ejj grams4 ,preliminary thermometric readings1 t #bf4h2 t #bg4b2 t #bg4g2 t #bh4a2 t #bh4e2 t #bh4i4 ,thermometric reading after combustion1 #bh4i2 #bjb2 #bac2 #bad4b2 #bad4j4 ,final thermometric readings1 t #bad4j2 t #bac4h2 t #bac4f2 t #bac4e2 t #bac4c2 t #bac4a2 t #bab4i2 t #bab4g2 t #bab4f2 t #bab4d2 t #bab4b4 ,from the formulas given above the following numerical values are computed3 v #j4db4 v -#j4ah4 t #bg4i4 t #bac4a4 n #e4 - r ------- #ffg4 #i ,substituting these values in the formula of ,regnault-,pfaundler1 the value of the correction for the influence of the external air is #j4db - 7-#j4ah7 #bad #bi t --------------- 7#fgg --------- - 7#e #bg4i77 #bac4a - #bg4i #b - 7#d #j4db7 #j4de1 which is to be added to the end temperature 7 #bad4j74 ,the computation is then made from the following data3 ,corrected end temperature 7 #j4de7 #bad4de #ae4cfii ,beginning temperature 77 #bh4ij #ab4hdjf ,increase in temperature #ahe4ee #b4ebic ,total calories #b4ebic #bejjj #fcbc4c ,of which there were due to iron burned #i4a 0 0 0 0 nitric acid dissolved #h4b ,total calories due to one gram of substance #ehic4e ,the thermometric readings are given in the divisions of the thermometer which in this case are so adjusted as to have the number #bh4ij correspond to #ab4hdjf1 and each division is nearly equivalent to #j4jad thermometric degree4 ,the number of calories above given is the proper one when the computation is made to refer to constant volume4 ,by reason of the consumption of oxygen and the change of temperature1 although mutually compensatory1 the pressure may be changed at the end of the operation4 ,the conversion of the data obtained at constant volume referred to constant pressure may be made by the following formula1 in which ,q represents the calories from constant volume and ,q the desired data for constant pressure1 ,o the number of oxygen atoms1 ,h the number of hydrogen atoms in a molecule of the substance1 and #j4bia a constant for a temperature of about #ah1 at which the observations should be made4 ,h ,q ,q 7--- - ,o7 #j4bia4 #b #eff4 ,calorimetric ,equivalents4--,by the term calorie is understood the quantity of heat required to raise one gram of water1 at an initial temperature of about #ah1 one degree4 ,the term #8,calorie' denotes the quantity of heat1 in like conditions1 required to raise one kilogram of water one degree4 ,for purposes of comparison and for assisting the analyst in adjusting his apparatus so as to give reliable results1 the following data1 giving the calories of some common food materials1 are given3 ,substance4 ,chemical composition4 ,proteids4 ,calories4 ,c4 ,h4 ,n4 ,s4 ,o4 ,per ,per ,per ,per ,per cent4 cent4 cent4 cent4 cent4 ,serum albumin #eiag4h #ec4ic #g4fe #ae4ae #a4ah #bb4ji ,casein #ehfg4j #ed4jb #g4cc #ae4eb #j4ge #bb4ch ,egg albumin #egce4j #eb4ie #g4ej #ae4ai #a4ea #bb4he ,meat free of fat and extracted with water #egbj4j #eb4aa #f4gf #ah4ad #j4if #bb4ff ,peptone #ebih4h #ej4aj #f4de #af4db #a4bd #be4gi ,proteids 7mean7 #egcj4h #eb4ga #g4ji #af4jb #a4jc #bc4ae ,glycerids4 ,butterfat #ibca4c ,linseed oil #idhh4j ,olive oil #idfg4j ,carbohydrates4 ,formula4 ,arabinose #cgbb4j ,c,h,o ,xylose #cgdf4j ,c,h,o ,dextrose #cgdb4f ,c,h,o ,levulose #cgee4j ,c,h,o ,sucrose #ciee4b ,c,h,o ,lactose #cgcf4h ,c,h,o ,h,o ,maltose #cidi4c ,c,h,o #efg4 ,distinction between ,butter and ,oleomargarin4--,theoretically the heats of combustion of butter fat and oleomargarin are different and de ,schweinitz and ,emery propose to utilize this difference for analytical purposes4#ehc ,the samples of pure butter fat examined by them afforded #icbj1 #icbg and #icfb calories1 respectively4 ,the calories obtained for various samples of oleomargarin varied from #iegd to #igie4 ,on mixing butter fat and oleomargarin1 a progressive increase in calorimetric power is found1 corresponding to the percentage of the latter constituent4 ,lards examined at the same time gave from #iejc to #ifed calories4 ,,fruits1 ,,melons ,,and ,,vegetables4 #efh4 ,preparation of ,sample4--,fresh fruits and vegetables are most easily prepared for analysis by passing them through the pulping machine described on page #i4 ,preliminary to the pulping they should be separated into skins1 cores1 seeds and edible portions1 and the respective weights of these bodies noted4 ,each part is separately reduced to a pulp and1 at once1 a small quantity of the well mixed substance placed in a flat bottom dish and dried1 first at a low temperature1 and finally at #ajj1 or somewhat higher1 and the percentage of water contained in the sample determined4 ,the bulk of the sample1 three or four kilograms1 is dried on a tray of tinned or aluminum wire1 first at a low and then at a high temperature1 until all or nearly all the moisture is driven off4 ,the dried pulp is then ground to as fine a powder as possible and subjected to the ordinary processes of analysis2 viz41 the determination of the moisture1 ash1 nitrogen1 fiber1 fat and carbohydrates4 ,in this method of analysis it is customary to determine the carbohydrates1 exclusive of fiber1 by subtracting the sum of the per cents of the other constituents and the nitrogen multiplied by #f4be from #ajj4 #efi4 ,separation of the ,carbohydrates4--,it is often desirable to determine the relative proportions of the more important carbohydrates which are found in fruits and vegetables4 ,the pentoses and pentosans are estimated by the method described in paragraph #aej4 ,the cane sugar1 dextrose and levulose are determined by extracting a portion of the substance with eighty per cent alcohol and estimating the reducing sugars in the extract before and after inversion by the processes described in paragraphs #bch-bea4 ,the percentages of sugars deducted from the percentage of carbohydrates1 exclusive of fiber1 give the quantity of gums1 pentosans1 cellulose and pectose bodies present4 ,pectose exists chiefly in unripe fruits4 ,by the action of the fruit acids and of a ferment1 pectose1 in the process of ripening1 is changed into pectin and similar hydrolyzed bodies soluble in water4 ,the gelatinous properties of boiled fruits and fruit juices are due to these bodies1 boiling accelerating their formation4 ,in very ripe fruits the pectin is completely transformed into pectic acids4 ,the galactan is estimated as described in #ehe4 #egj4 ,examination of the ,fresh ,matter4--,to avoid the changes which take place in drying fruits and vegetables1 it is necessary to examine them in the fresh state4 ,the samples may be first separated into meat and waste1 as suggested above1 or shredded as a whole4 ,the moisture in the pulp is determined as indicated above1 and in a separate portion the soluble matters are extracted by repeated treatment with cold water4 ,the seeds1 skins1 cellulose1 pectose and other insoluble bodies are thus separated from the sugars1 pectins1 pectic and other acids1 and other soluble matters4 ,the insoluble residue is rapidly dried and the relative proportions of soluble and insoluble matters determined4 ,the estimation of these bodies is accomplished in the usual way4 #ega4 ,examination of ,fruit and ,vegetable ,juices4--,the fruits and vegetables are pulped1 placed in a press and the juices extracted4 ,the pressure should be as strong as possible and the press described in paragraph #bhj is well suited to this purpose4 ,the specific gravity of the expressed juice is obtained and the sucrose therein determined by polarization before and after inversion4 ,the reducing sugars and the relative proportions of dextrose and levulose are determined in the usual manner4 ,in grape juice dextrose is the predominant sugar while in many other fruits left hand or optically inactive sugars predominate4 ,soluble gums1 dextrin1 pectin etc41 may be separated from the sugars by careful precipitation with alcohol1 or the total solids1 ash1 nitrogen1 ether extract and acids be determined and the carbohydrates estimated by difference4 ,from the carbohydrates the total percentage of sugars is deducted and the remainder represents the quantity of pectin1 gum and other carbohydrates present4 #egb4 ,separation of ,pectin4--,pectin exists in considerable quantities in the juice of ripe fruits 7pears7 and may be obtained in an approximately pure state from the juices by first removing proteids by the careful addition of tannin1 throwing out the soluble lime salts with oxalic acid and precipitating the pectin with alcohol4 ,on boiling with water1 pectin is converted into parapectin1 which gives a precipitate with lead acetate4 ,boiling with dilute acids converts pectin into metapectin1 which is precipitated by a barium salt4 ,pectic acid may be obtained by boiling an aqueous extract 7carrots7 with sodium carbonate and precipitating the pectic with hydrochloric acid4 ,it is a jelly-like body and dries to a horny mass4 #egc4 ,determination of ,free ,acid4--,the free acid1 or rather total acidity of fruits1 is determined by the titration of their aqueous extracts or expressed juices with a set alkali4 ,in common fruits and vegetables the acidity is calculated to malic ,c,h,o1 in grapes to tartaric ,c,h,o1 and in citrous fruits to citric acid ,c,h,o4 ,many other acids are found in fruits and vegetables1 but those mentioned are predominant in the classes given4 #egd4 ,composition of ,common ,fruits4--,the composition of common fruits in this country has been extensively investigated at the ,california ,station and the following data are derived chiefly from its bulletins4#ehd ,name4 ,total ,rind ,seed4 ,pulp4 ,juice4 ,total weight4 skin4 sugars ,sucrose in in juice4 juice4 per per per cubic per per grams4 cent4 cent4 cent4 centimeters4 cent4 cent4 ,naval orange #cjj #bh4d #bg4g #ajg #i4ib #d4hj ,mediterranean sweet orange #bjb #bg4j #j4h #bd4j #hf #i4gj #d4ce ,st4 ,michael's orange #ach #ai4b #a4f #be4i #fe4d #h4ga #c4dh ,malta ,blood orange #agg #ca4j #bd4j #ga4j #aj4cj #e4he ,eureka lemon #ajd #cb #j4ab #bd4e #ch #b4jh #j4eg ,flesh ,per cent ,apricot #fb4d #ic4he #f4ae #aj4j #ij4j #ac4ca ,prune #be4f #id4b #e4h #ba4b #gh4h #bj4j ,plum #fj4d #ie4b #d4h #bd4g #ge4c #ag4ig ,peach #ahe #ic4h #f4b #bb4e #gg4e #ag4j ,skin ,cores ,apple #ahc #ag4j #g4j #aj4bf #a4ec ,in whole fresh fruit4 ---------------------------------------- ---------------------------- ,in whole fruit4 _/----------------------------- ,name4 ,acid4 ,nitrogenous ,water4 ,dry ,ash4 bodies4 organic matter4 per per per per per cent4 cent4 cent4 cent4 cent4 ,naval orange #a4jb #a4ca #hf4ef #ac4jd #j4dj ,mediterranean sweet orange #a4ch #j4if #he4hc #ac4jf #j4da ,st4 ,michael's orange #a4ce #a4dc #hd4aj #ae4db #j4dh ,malta ,blood orange #a4fa #a4je #hd4ej #ae4je #j4de ,eureka lemon #g4ff #j4id #he4ii #ac4ej #j4ea ,apricot #j4fh #a4be #he4af #ad4ce #j4di ,prune #j4dj #a4ja #gg4ch #bb4ah #j4dd ,plum #j4dh #a4cc #gg4dc #bb4jd #j4ec ,peach #j4be #hb4ej #af4ie #j4ee ,apple#ehe #j4aa #hf4dc #ac4bh #j4bi #ege4 ,composition of ,ash of ,fruits4--,two or three kilograms of the dried sample are incinerated at a low temperature and burned to a white ash in accordance with the directions given in paragraphs #bh-cb4 ,the composition of the ash is determined by the methods already described4#ehf ,the pure ash of some common whole fruits has the following composition3#ehg ,name4 ,per ,per ,per ,per ,per ,per ,per cent cent cent cent cent cent cent pure potash4 soda4 lime4 magnesia4 ferric mangano- ash oxid4 manganic in oxid4 fruit4 ,prune #j4dg #fc4hc #b4fe #d4ff #e4dg #b4gb #j4ci ,apricot #j4ea #ei4cf #aj4bf #c4ag #c4fh #a4fh #j4cg ,orange #j4dc #dh4id #b4ej #bb4ga #e4cd #j4ig #j4cg ,lemon #j4ec #dh4bf #a4gf #bi4hg #d4dj #j4dc #j4bh ,apple #a4dd #ce4fh #bf4ji #d4jh #h4ge #a4dj ,pear #a4ig #ed4fi #h4eb #g4ih #e4bb #a4jd ,peach #d4ij #bg4ie #j4bc #h4ha #ag4ff #j4ee ---------------------------------------- -------------------- ,name4 ,per ,per ,per ,per cent cent cent cent phosphorus sulfur silica4 chlorin4 pentoxid4 trioxid4 ,prune #ad4jh #b4fh #c4jg #j4cd ,apricot #ac4ji #b4fc #e4bc #j4de ,orange #ab4cg #e4be #j4fe #j4ib ,lemon #aa4ji #b4hd #j4ff #j4ci ,apple #ac4ei #f4ji #d4cb ,pear #ae4bj #e4fi #a4di ,peach #dc4fc #j4cg #egf4 ,dried ,fruits4--,a method of preserving fruits largely practiced consists in subjecting them1 in thin slices or whole1 to the action of hot air until the greater part of the moisture is driven off4 ,the technique of the process is fully described in recent publications4#ehh ,it has been shown by ,richards that fruit subjected to rapid evaporation undergoes but little change aside from the loss of water4#ehi ,in the analyses of dried fruits the methods already described are used4 ,the presence of pectin renders the filtration of the aqueous extract somewhat difficult1 and in many cases it is advisable to determine the sugars present in the extract without previous filtration4 #egg4 ,zinc in ,evaporated ,fruits4--,fruits are commonly evaporated on trays made of galvanized iron4 ,in these instances a portion of the zinc is dissolved by the fruit acids1 and will be found as zinc malate etc41 in the finished product4 ,the presence of zinc salts is objectionable for hygienic reasons1 and therefore the employment of galvanized trays should be discontinued4 ,the presence of zinc in evaporated fruits may be detected by the following process4#eij ,the sample is placed in a large platinum dish and heated slowly until dry and in incipient combustion4 ,the flame is removed and the combustion allowed to proceed1 the lamp being applied from time to time in case the burning ceases4 ,when the mass is burned out it will be found to consist of ash and char1 which are ground to a fine powder and extracted with hydrochloric or nitric acid4 ,the residual char is burned to a white ash at a low temperature1 the ash extracted with acid1 the soluble portion added to the first extract and the whole filtered4 ,the iron in the filtrate is oxidized by boiling with bromin water and the boiling continued until the excess of bromin is removed4 ,a drop of methyl orange is placed in the liquid and ammonia added until it is only faintly acid4 ,the iron is precipitated by adding fifty cubic centimeters of a solution containing #bej grams of ammonium acetate in a liter and raising the temperature to about #hj4 ,the precipitate is separated by filtration and washed with water at #hj until free of chlorids4 ,the filtrate is saturated with hydrogen sulfid1 allowed to stand until the zinc sulfid settles and poured on a close filter4 ,it is often necessary to return the filtrate several times before it becomes limpid4 ,the collected precipitate is washed with a saturated solution of hydrogen sulfid containing a little acetic acid4 ,the precipitate and filter are transferred to a crucible1 dried1 ignited and the zinc weighed as oxid4 ,small quantities of zinc salts added to fresh apples which were dried and treated as above described1 were recovered by this method without loss4 ,other methods of estimating zinc in dried fruits are given in the bulletin cited4 ,evaporated apples contain a mean content of #bc4he per cent of water and #j4ica per cent of ash4 ,the mean quantity of zinc oxid found in samples of apples dried in the ,united ,states is ten milligrams for each #ajj grams of the fruit1 an amount entirely too small to produce any toxic effects4 ,when zinc exists in the soil it will be found as a natural constituent in the crop4#eia #egh4 ,composition of ,watermelons and ,muskmelons4--,in the examination of melons a separation of the rind1 seeds and meat is somewhat difficult of accomplishment1 since the line of demarcation is not distinct4 ,in watermelons the separation of rind and meat is made at the point where the red color of the meat disappears4 ,in muskmelons no such definite point is found and in the examination of these they are taken as a whole4 ,the total moisture1 ash and nitrogen may be determined in the whole mass or in the separate portions4 ,the sugars are most conveniently determined in the expressed juices4 ,the mean composition of the melons given below is that obtained from analyses made in the ,department of ,agriculture4#eib ,,composition ,,of ,,melons4 ,total ,total weight1 ,juice1 proteids1 ,ash1 grams4 per cent4 per cent4 per cent4 ---------------------------------------- --------------------- ,watermelons #ajccj meat #hc4ii #f4ab #j4cg rind #ha4jb ---------------------------------------- --------------------- ,muskmelons #cdjg #hj4bc #f4de #j4eg ,,composition ,,of ,,juice4 ,sucrose in ,reducing sugars ,ash in juice1 in juice1 juice1 per cent4 per cent4 per cent4 ---------------------------------------- --------------------- ,watermelons meat #a4ib meat #d4cc meat #j4ca rind #j4cd rind #b4dg rind #j4ch ---------------------------------------- --------------------- ,muskmelons #a4jb #c4jd #j4ec ,,tea ,,and ,,coffee4 #egi4 ,special ,analysis4--,aside from the examination of teas and coffees for adulterants1 the only special determinations which are required in analyses are the estimation of the alkaloid 7caffein7 and of the tannin contained therein4 ,it is chiefly to the alkaloid that the stimulating effects of the beverages made from tea and coffee are due4 ,the determination of the quantity of tannin contained in tea and coffee is accomplished by the processes described under the chapter devoted to that glucosid4 ,the general analysis1 viz41 the estimation of water1 ether extract1 total nitrogen1 fiber1 carbohydrates and ash1 with the exceptions noted above1 is conducted by the methods which have already been given4 ,for detailed instructions concerning the detection of adulterants of tea and coffee the bulletins of the ,chemical ,division1 ,department of ,agriculture1 may be consulted4#eic #ehj4 ,estimation of ,caffein 7,thein74--,the method adopted by ,spencer1 after a thorough trial of all the usual processes for estimating this alkaloid1 is as follows3#eid ,to three grams of the finely powdered tea or coffee1 in a #cjj cubic centimeter flask1 add about a quarter of a liter of water1 slowly heat to the boiling point1 using a fragment of tallow to prevent frothing1 and boil gently for half an hour4 ,when boiling begins1 the flask should be nearly filled with hot water and more added from time to time to compensate for the loss due to evaporation4 ,after cooling1 add a strong solution of basic lead acetate until no further precipitation is produced1 complete the volume to the mark with water1 mix and throw on a filter4 ,precipitate the lead from the filtrate by hydrogen sulfid and filter4 ,boil a measured volume of this filtrate to expel the excess of hydrogen sulfid1 cool and add sufficient water to compensate for the evaporation4 ,transfer fifty cubic centimeters of this solution to a separatory funnel and shake seven times with chloroform4 ,collect the chloroform solution in a tared flask and remove the solvent by gentle distillation4 ,a safety bulb1 such as is used in the kjeldahl nitrogen method1 should be employed to prevent entrainment of caffein with the chloroform vapors4 ,the extraction with chloroform is nearly complete after shaking out four times2 a delicate test1 however1 will usually reveal the presence of caffein in the watery residue even after five or six extractions1 hence seven extractions are recommended for precautionary reasons4 ,the residual caffein is dried at #ge for two hours and weighed4 ,the principal objection which has been made to ,spencer's method is that the boiling with water is not continued for a sufficient length of time4 ,for the water extraction1 ,allen prescribes at least six hours cohobation4#eie ,in this method six grams of the powdered substance are boiled with half a liter of water for six hours in a flask1 with a condenser1 the decoction filtered1 the volume of the filtrate completed to #fjj cubic centimeters with the wash water1 heated to boiling1 and four cubic centimeters of strong lead acetate solution added1 the mixture boiled for ten minutes1 filtered and half a liter of the filtrate evaporated to fifty cubic centimeters4 ,the excess of lead is removed with sodium phosphate and the filtrate and washings concentrated to about forty cubic centimeters4 ,the caffein is removed by shaking four times with chloroform4 ,older but less desirable processes are fully described by ,allen4#eif ,in ,france this method is known as the process of ,petit and ,legrip1 and it has been worked out in great detail by ,grandval and ,lajoux and by ,petit and ,terbat4#eig #eha4 ,estimation of ,caffein by ,precipitation with ,iodin4--,the caffein in this method is extracted1 the extract clarified by lead acetate and the excess of lead removed as in ,spencer's process described above4 ,the caffein is determined in the acidified aqueous solution thus prepared1 according to the plan proposed by ,gomberg1 as follows3#eih ,definite volumes of the aqueous solution of the caffein are acidulated with sulfuric and the alkaloid precipitated by an excess of a set solution of iodin in potassium iodid4 ,after filtering1 the excess of iodin in an aliquot part of the filtrate is determined by titration with a tenth normal solution of sodium thiosulfate4 ,the filtration of the iodin liquor is accomplished on glass wool or asbestos4 ,the results of the analyses are calculated from the composition of the precipitated caffein periodid2 viz41 ,c,h,n,o4,,hi4,i4 ,the weight of the alkaloid is calculated from the amount of iodin required for the precipitation by the equation #d;,i3 ,c,h,n,o #ejh3 #aid4 ,from this equation it is shown that one part of iodin is equivalent to #j4chai part of caffein1 or one cubic centimeter of tenth normal iodin solution is equal to #j4jjdhe gram of iodin4 ,in practice1 it is recommended to divide the aqueous extract of the alkaloid1 prepared as directed above1 into two portions1 one of which is treated with the iodin reagent without further preparation1 and the other after acidulation with sulfuric4 ,after ten minutes1 the residual iodin is estimated in each of the solutions as indicated above4 ,the one portion1 containing only the acetic acid resulting from the decomposition of the lead acetate1 serves to indicate whether the aqueous solution of the caffein contains other bodies than that alkaloid capable of forming a precipitate with the reagent1 since the caffein itself is not precipitated even in presence of strong acetic acid4 ,in the solution acidulated with sulfuric1 the caffein1 together with the other bodies capable of combining with iodin1 is precipitated4 ,the residual iodin is determined in each case1 and thus the quantity which is united with the caffein is easily ascertained4 ,the weight of iodin which has entered into the precipitated caffein periodid multiplied by #j4chai gives the weight of the caffein in the solution4 ,gomberg's method has been subjected to a careful comparative study by ,spencer and has been much improved by him in important particulars4#eii ,it is especially necessary to secure the complete expulsion of the hydrogen sulfid and to observe certain precautions in the addition of the iodin reagent4 ,the precipitation should be made in a glass-stoppered flask1 shaking thoroughly after the addition of the iodin and collecting the precipitate on a gooch4 ,as thus modified1 the iodin process gives results comparable with those obtained by ,spencer's method1 and it can also be used to advantage in estimating caffein in headache tablets in the presence of acetanilid4 #ehb4 ,freeing ,caffein of ,chlorophyll4--,any chlorophyll which may pass into solution and be found in the caffein may be removed by dissolving the caffein in ten per cent sulfuric acid1 filtering1 neutralizing with ammonia and evaporating to dryness4 ,the residue is taken up with chloroform1 the chloroform removed at a low temperature and the pure caffein thus obtained4#fjj #ehc4 ,proteid ,nitrogen4--,the proteid nitrogen in tea and coffee may be determined in the residue after extraction of the alkaloid by boiling water as described above4 ,more easily it is secured by determining the total nitrogen in the sample and deducting therefrom the nitrogen present as caffein4 ,the remainder1 multiplied by #f4be1 will give the quantity of proteid matter4 #ehd4 ,carbohydrates of the ,coffee ,bean4--,the carbohydrates of the coffee bean include those common to vegetable substances2 viz41 cellulose1 pentosan bodies 7xylan1 araban71 fiber etc41 together with certain sugars1 of which sucrose is pointed out by ,ewell as the chief4#fja ,in smaller quantities are found a galactose yielding body 7galactan71 as pointed out by ,maxwell1 a dextrinoid and a trace of a sugar reducing alkaline copper solution4 ,the sucrose may be separated from the coffee bean by the following process3#fjb ,the finely ground flour is extracted with seventy per cent alcohol1 the extract clarified with lead acetate1 filtered1 the lead removed from the filtrate with hydrogen sulfid1 the excess of the gas removed by boiling1 the filtrate evaporated in a partial vacuum to a sirup and the sucrose crystallized from a solution of the sirup in alcohol4 ,for a quantitive determination1 ten grams of the coffee flour are extracted with ether and the residue with seventy-five per cent alcohol4 ,this process1 conducted in a continuous extraction apparatus1 should be continued for at least twenty-four hours4 ,the alcohol is removed by evaporation1 the residue dissolved in water1 clarified with basic lead acetate1 filtered1 the precipitate washed1 the lead removed1 again filtered1 the filtrate washed and wash water and filtrate made to a definite volume4 ,in an aliquot part of this solution the sugars are determined by the alkaline copper method1 both before and after inversion4 ,from the data obtained the percentage of sucrose is calculated4 ,in a coffee examined by ,ewell the percentage of sucrose was found to be #f4cd4 ,the pentose yielding constituents of the coffee bean amount to from eight to ten per cent4 ,when coffee meal is extracted with a five per cent solution of sodium carbonate1 a gummy substance is obtained1 which is precipitable by alcohol4 ,this gum1 after washing with hydrochloric acid containing alcohol1 gives a gray1 translucent1 hard mass on drying4 ,on hydrolysis it yielded #ge4b per cent of dextrose1 on distillation with hydrochloric acid1 thirteen per cent of furfuraldehyd and1 on oxidation with nitric acid1 #ah4g per cent of mucic acid4 ,this gum1 therefore1 consists chiefly of a mixture of galactan1 xylan and araban4 #ehe4 ,estimation of ,galactan4--,from three to five grams of the substance supposed to contain galactan are placed in a beaker with sixty cubic centimeters of nitric acid of #a4ae specific gravity4 ,the mixture is evaporated on a steam bath until it is reduced to one-third of its original volume1 allowed to stand for twenty-four hours1 ten cubic centimeters of water added1 well stirred and again allowed to stand for twenty-four hours1 until the mucic acid is separated in a crystalline form4 ,to remove impurities from the mucic acid it is separated by filtration1 washed with not to exceed twenty cubic centimeters of water1 placed together with the filter in the beaker1 from twenty-five to thirty cubic centimeters of ammonium carbonate solution1 containing one part of dry ammonium carbonate1 nineteen parts of water and one part of ammonium hydroxid1 added and heated to near the boiling point4 ,the mucic acid is dissolved by the ammonium carbonate solution and any insoluble impurity separated by filtration1 the filtrate being received in a platinum dish1 the residue well washed and the entire filtrate and wash water evaporated to dryness on a steam bath acidified with dilute nitric1 well stirred and allowed to stand until the mucic acid separates in a crystalline form4 ,the separation is usually accomplished in half an hour1 after which time the crystals of mucic acid are collected on a tared filter1 or gooch1 and washed with not to exceed fifteen cubic centimeters of water followed with sixty cubic centimeters of alcohol1 then with ether1 dried at #ajj and weighed4 ,for computing the amount of galactose1 one gram of the mucic acid is equal to #a4ccc of galactose and one gram of galactose is equal to nine-tenths gram of galactan4 ,before the commencement of the operation1 the material should be freed of fatty matters in the case of oily seeds and other substances similar thereto4#fjc #ehf4 ,revised ,factors for ,pentosans4--,the factors given in paragraph #aed have lately been recalculated by ,mann1 ,kruger and ,tollens1 and as a result of their investigations the following factors are now recommended4#fjd ,the quantity of furfurol is derived from the weight of furfurolhydrazone obtained by the formula3 #a4 ,furfurolhydrazone #j4eaf #j4jajd furfurol4 #b4 ,furfurol #a4hd pentosans4 #c4 ,furfurol #a4fd xylan4 #d4 ,furfurol #b4jb araban4 ,the pentoses 7xylose1 arabinose7 may be calculated from the pentosans 7xylan1 araban7 by dividing by #j4hh4 ,the method of procedure preferred for the estimation of the pentosans is that described in paragraph #aeg4 ,the phloroglucin is dissolved in hydrochloric acid of #a4jf specific gravity before it is added to the furfurol distillate4 ,the latest factor for converting the phloroglucid obtained into furfurol is to divide by #a4hb for small quantities and #a4ic for large quantities4 ,after the furfurol is obtained1 the factors given above are applied4 #ehg4 ,application of ,roentgen ,rays to ,analysis4--,the detection of mineral matters in vegetable substances by roentgen photography has been proposed by ,ranvez4#fje ,this process will prove extremely valuable in detecting the lacing of teas with mineral substances4 ,practically1 it has been applied by ,ranvez in the detection of mineral substances mixed with saffron with fraudulent intent4 ,barium sulfate is often mixed with saffron for the purpose of increasing its weight4 ,pure saffron and adulterated samples are enclosed in capsules of black paper and exposed on the same sensitive plate for a definite time to the rays emanating from a crookes tube4 ,in this case the pure saffron forms only a very faint shadow in the developed negative1 while the parts to which barium sulfate are attached produce strong shadows4 ,the principle involved is applicable to a wide range of analytical research4 ,,tannins ,,and ,,allied ,,bodies4 #ehh4 ,occurrence and ,composition4--,the tannins and allied bodies1 which are of importance in this connection1 are those which occur in food products and beverages and also those made use of in the leather industry4 ,the term tannin is applied to a large class of astringent substances1 many of which are glucosids4 ,tannic acid is the chief constituent of the tannins1 and is found in a state of comparative purity in nutgalls4 ,the source from which the tannic acid is derived is indicated by a prefix to the name1 e4 g41 gallotannic1 from nutgalls1 and caffetannic1 from coffee etc4 ,the tannins have lately been the theme of a critical study by ,trimble1 and the reader is referred to his work for an exhaustive study of the subject4#fjf ,tannin is one of the most widely diffused compounds1 occurring in hundreds of plants4 ,commercially1 the oaks and hemlocks are the most important plants containing tannin4 ,the sumach1 mangrove1 canaigre1 palmetto and many others have also been utilized as commercial sources of tannin4 ,the tannins as a class are amorphous and odorless4 ,they are slightly acid and strongly astringent4 ,their colors vary from dark brown to pure white4 ,they are soluble in water1 alcohol1 ether and glycerol and insoluble in chloroform1 benzol1 petroleum ether1 carbon bisulfid and the oils4 ,the tannins give blue or green precipitates with iron salts and most of them brown precipitates with potassium bichromate4 ,they are all precipitated by gelatin or albumin4 ,tannins are not only generally of a glucosidal nature1 but are found quite constantly associated with reducing sugars1 or in unstable combination therewith4 ,the reducing sugars may be separated from the tannin by precipitating the latter with lead acetate and determining the glucose in the filtrate after the removal of the lead4 ,a separate portion of the tannin is hydrolyzed with sulfuric or hydrochloric acid and the reducing sugars again determined4 ,any excess of sugars over the first determination is due to the hydrolysis of the tannin glucosid4 #ehi4 ,detection and ,estimation of ,tannins4--,the qualitive reactions above mentioned serve to detect the presence of a tannin4 ,of the iron salts ferric acetate or chlorid is preferred4 ,ferrous salts do not give any reaction with dilute tannin solutions4 ,an ammoniacal solution of potassium ferricyanid forms with tannins a deep red color changing to brown4 ,in quantitive work the tannins are mostly determined by precipitation with metallic salts1 by treatment with gelatin or hide powder1 or by oxidation with potassium permanganate4 ,directions for the estimation of glucosids in general are found in ,dragendorff's book4#fjg #eij4 ,precipitation with ,metallic ,salts4--,the methods depending on precipitation of the tannins with metallic salts are but little used and only one of them will be mentioned here4 ,a full description of the others is contained in ,trimble's book4#fjh ,a method for the determination of caffetannic acid in coffee has been worked out by ,krug and used with some satisfaction4#fji ,in this method two grams of the coffee meal are digested for thirty-six hours with ten cubic centimeters of water1 a little more than twice that volume of ninety-five per cent alcohol added and the digestion continued for a day4 ,the contents of the flask are poured on a filter and the residue washed with alcohol4 ,the filtrate contains tannin1 caffetannic acid and traces of coloring matter and fat4 ,it is heated to the boiling point and clarified with a solution of lead acetate4 ,a caffetannate of lead containing forty-nine per cent of the metal is precipitated4 ,as soon as the precipitate has become flocculent it is collected on a filter1 washed with ninety per cent alcohol until the soluble lead salts are all removed1 then with ether and dried4 ,the composition of the precipitate is represented by the formula ,pb7,c,h,o74 ,the caffetannic acid is calculated by the equation3 ,weight of precipitate3 weight of caffetannic acid #abfg3 #feb4 #eia4 ,the ,gelatin ,method4--,the precipitation of tannin with gelatin is the basis of a process for its quantitive estimation which1 according to ,trimble1 is conducted as follows3#faj ,two and a half grams of gelatin and ten grams of alum are dissolved in water and the volume of the solution made up to one liter4 ,the solution of gelatin and also that of the tannin are heated to #gj and the tannin is precipitated by adding the gelatin reagent slowly1 with constant stirring1 until the precipitate coagulates1 and1 on settling1 leaves a clear liquor in which no further precipitate is produced on adding a few drops more of the reagent4 ,in case the clearing of the mixture do not take place readily1 the process should be repeated with a more dilute tannin solution4 ,the precipitate is collected on two counterpoised filter papers one placed inside the other1 dried at #aaj and weighed1 the empty filter paper being placed on the pan with the weights4 ,for pure tannin 7gallotannic acid7 fifty-four per cent of the weight of the precipitate are tannin4 ,ammonium chlorid and common salt have been used in place of the alum in preparing the reagent1 but if the proportion of alum mentioned above be used1 satisfactory results will be obtained in most cases4 #eib4 ,the ,hide ,powder ,method4--,the principle of this method is based on the change in specific gravity1 i4 e41 total solids1 which a tannin solution will undergo when brought into contact with raw hides in a state of fine subdivision4 ,the hide powder absorbs the tannin1 and the total solid content of the solution is correspondingly diminished4 ,the method is conducted according to the official directions as follows3#faa ,preparation of the ,sample4--,the bark1 wood1 leaves or other materials holding the tannins1 are dried and ground to a fine powder and thoroughly extracted with water as mentioned below4 ,in each case the solution or extraction is made as thorough as possible and the volume of the extract is made up to a definite amount4 ,quantity of ,tanning ,material4--,use such an amount of the tanning material as shall give in #ajj cubic centimeters of the filtered solution about one gram of dry solids4 ,in the case of barks1 woods1 leaves and similar materials1 transfer to a half liter flask1 fill the flask with water at approximately #hj and let stand over night in a bath which is kept at #hj1 cool1 fill to the mark1 shake well and filter4 ,in the case of extracts and sweet liquors1 wash the proper quantity into a half liter flask with water at approximately #hj1 almost filling the flask1 cool and fill to the mark4 ,determination of ,moisture4--,dry five grams of the sample in a flat bottom dish at the temperature of boiling water until the weight becomes constant4 ,determination of ,total ,solids4--,shake the solution1 which should be at a temperature of about #bj1 and immediately remove #ajj cubic centimeters with a pipette1 evaporate in a weighed dish and dry to constant weight at the temperature of boiling water4 ,determination of ,soluble ,solids4--,filter a portion of the solution through a folded filter1 returning the filtrate to the filter twice and adding a teaspoonful of kaolin1 if necessary4 ,evaporate #ajj cubic centimeters of the filtrate and dry as above4 ,determination of ,tanning ,substances4--,extract twenty grams of hide powder by shaking for five minutes with #bej cubic centimeters of water1 filter through well washed muslin or linen1 repeat the operation three times and dry as much as possible in a suitable press4 ,weigh the wet powder and determine the residual moisture in about one-fourth of the whole by drying to constant weight at #ajj4 ,shake #bjj cubic centimeters of the unfiltered solution of the tannin with the rest of the moist hide powder for about five minutes1 add five grams of barium sulfate1 shake for one minute and filter through a schleicher and schll folded filter1 ,no4 #eij1 fifteen centimeters in diameter1 returning the first twenty-five cubic centimeters of the filtrate4 ,evaporate #ajj cubic centimeters of the clear filtrate and dry the residue to constant weight at a temperature of boiling water4 ,the difference between the soluble solids obtained in the filtered tannin solution and the residue as obtained above is the amount of tanning material absorbed by the hide powder4 ,this weight must be corrected for the water retained by the hide powder4 ,the shaking must be conducted by means of a mechanical shaker1 in order to remove all the tannin substance from the solution4 ,the simple machine used by druggists1 and known as the milkshake1 is recommended4 ,testing the ,hide ,powder4--,shake ten grams of the hide powder with #bjj cubic centimeters of water for five minutes1 filter through muslin or linen1 squeeze out thoroughly by hand1 replace the residue in the flask and repeat the operation twice with the same quantity of water4 ,pass the last filtrate through paper until a perfectly clear liquid is obtained4 ,evaporate #ajj cubic centimeters of the final filtrate in a weighed dish1 dry at #ajj until the weight is constant4 ,if the residue amount to more than ten milligrams the sample should be rejected4 ,the hide powder must be kept in a dry place and tested once a month4 ,prepare a solution of pure gallotannic acid by dissolving five grams in one liter of water4 ,determine the total solids by evaporating #ajj cubic centimeters of this solution and drying to constant weight4 ,treat #bjj cubic centimeters of the solution with hide powder exactly as described above4 ,the hide powder must absorb at least ninety-five per cent of the total solids present4 ,the gallotannic acid used must be completely soluble in water1 alcohol1 acetone and acetic ether and should contain not more than one per cent of substances not removed by digesting with excess of yellow mercuric oxid on the steam bath for two hours4 ,testing the ,non-,tannin ,filtrate4 ,for ,tannin3--,test a small portion of the clear non-tannin filtrate with a few drops of a ten per cent solution of gelatin4 ,a cloudiness indicates the presence of tannin1 in which case the determination must be repeated1 using twenty-five grams of hide powder instead of twenty grams4 ,for ,soluble ,hide3--,to a small portion of the clear non-tannin filtrate1 add a few drops of the original solution1 previously filtered to remove reds4 ,a cloudiness indicates the presence of soluble hide due to incomplete washing of the hide powder4 ,in this case1 repeat the determination with perfectly washed hide powder4 #eic4 ,the ,permanganate ,gelatin ,method4--,this process1 which is essentially the method of ,lwenthal1 as improved by ,councler1 ,schroeder and ,proctor and as used by ,spencer for the determination of tannin in teas1 is conducted as described below4#fab ,the principle of the process is based on the oxidation of all bodies in solution oxidizable by potassium permanganate1 the subsequent precipitation of the tannin by a gelatin solution1 and the final oxidation1 by means of permanganate1 of the remaining organic bodies4 ,the difference between the total oxidizable matter and that left after the precipitation of the tannin represents the tannin originally in solution4 ,reagents ,required4--,the following reagents are necessary to the proper conduct of the potassium permanganate process3 7#a74 ,potassium permanganate solution containing about one and a third grams of the salt in a liter3 ,the potassium permanganate solution is set by titration against the decinormal oxalic acid solution mentioned below4 ,the end reaction with the indicator must be of the same tint in all the titrations1 i4 e41 either golden yellow or pink4 7#b74 ,tenth-normal oxalic acid solution for determining the exact titer of the permanganate solution3 7#c74 ,indigo-carmin solution to be used as an indicator and containing six grams of indigo-carmin and fifty cubic centimeters of sulfuric acid in a liter4 ,the indigo-carmin must be very pure and quite free of indigo-blue4 7#d74 ,gelatin solution1 prepared by digesting twenty-five grams of gelatin at room temperature for one hour in a saturated solution of sodium chlorid1 then heating until solution is complete1 cooling and making the volume up to one liter3 7#e74 ,a salt acid solution1 made by adding to #ige cubic centimeters of a saturated solution of sodium chlorid1 enough strong sulfuric acid to bring the volume of the mixture to one liter3 7#f74 ,powdered kaolin for promoting filtration4 ,the ,process4--,five grams of the finely powdered tea 7or other vegetable substance containing tannin7 are boiled with distilled water in a flask of half a liter capacity for half an hour4 ,the distilled water should be at room temperature when poured over the powdered tea4 ,after cooling1 the volume of the decoction is completed to half a liter1 and the contents of the flask poured on a filter4 ,to ten cubic centimeters of the filtered tea infusion are added two and a half times as much of the indigo-carmin solution and about three-quarters of a liter of distilled water4 ,the permanganate solution is run in from a burette1 a little at a time1 with vigorous stirring1 until the color changes to a light green1 and then drop by drop until the final color selected for the end of the reaction1 golden yellow or faint pink1 is obtained4 ,the number of cubic centimeters of permanganate required is noted and represented by a in the formula below4 ,the titration should be made in triplicate and the mean of the two more nearly agreeing readings taken as the correct one4 ,one hundred cubic centimeters of the filtered tea infusion1 obtained as directed above1 are mixed with half that quantity of the gelatin reagent1 the first named quantity of the acid salt solution added1 together with ten grams of the powdered kaolin1 the mixture well shaken for several minutes and poured on a filter4 ,twenty-five cubic centimeters of the filtrate1 corresponding to ten of the original tea solution are titrated with the permanganate reagent1 under the conditions given above1 and the reading of the burette made and represented by b4 ,the quantity of permanganate solution1 viz41 c1 required to oxidize the tannin is calculated from the formula a - b c4 ,the relation between the permanganate1 oxalic acid and tannin is such that #j4jdaeg gram of gallotannic acid is equivalent to #j4jfc gram of oxalic acid4 ,the relation between the oxalic acid solution and the permanganate having been previously determined the data for calculating the quantity of tannin1 estimated as gallotannic acid1 are at hand4 #eid4 ,the ,permanganate ,hide ,powder ,method4--,instead of throwing out the tannin with gelatin it may be absorbed by hide powder4 ,the principle of the process1 save this modification1 is the same as in the method just described4 ,as described by ,trimble1 the analysis is conducted according to the following directions3#fac ,reagents ,required4--,the reagents required for conducting the permanganate hide powder process are as follows3 #a4 ,permanganate ,solution4--,ten grams of pure potassium permanganate are dissolved in six liters of water4 ,the solution is standardized with pure tannin4 ,the moisture in the pure tannin is determined by drying at #ajj to constant weight and then a quantity of the undried substance1 representing two grams of the dried material1 is dissolved in one liter of water4 ,ten cubic centimeters of this solution and double that quantity of the indigo solution to be described below1 are mixed with three-quarters of a liter of water and the permanganate solution added from a burette with constant stirring until the liquid assumes a greenish color and then1 drop by drop1 until a pure yellow color with a pinkish rim is obtained4 ,fifty cubic centimeters of the pure tannin solution are digested1 with frequent shaking1 with three grams of hide powder which has been previously well moistened and dried in a press for eighteen or twenty hours1 the contents of the flask thrown on a filter and ten cubic centimeters of the filtrate titrated with the permanganate solution as directed above4 ,the difference between the amount of permanganate solution required for the first and second titrations represents the amount of pure tannin or oxidizable matter removed by the hide powder4 #b4 ,indigo ,solution4--,the indicator which is used in the titrations is prepared by dissolving thirty grams of sodium sulfindigotate in three liters of dilute sulfuric acid made by adding one volume of the strong acid to three volumes of water4 ,the solution is shaken for a few minutes1 thrown upon a filter and the insoluble residue washed with sufficient water to make the volume of the filtrate six liters4 #c4 ,hide ,powder4--,the hide powder used should be white1 wooly in character and sufficiently well extracted with water to afford no other extract capable of oxidizing the permanganate solution4 ,the ,process4--,the reagents having been prepared and tested as above1 the solution of the substance containing the tannin1 prepared as described further on1 is titrated first with the permanganate solution in the manner already given4 ,fifty cubic centimeters of the tannin solution are then shaken1 from1 time to time for eighteen hours1 with three grams of hide powder1 thrown upon a filter and ten cubic centimeters of the filtrate titrated with the potassium permanganate as above described4 ,from the data obtained1 the quantity of permanganate solution corresponding to the tannin removed by the hide powder is easily calculated4 ,the value of the permanganate solution having been previously set with a pure tannin1 renders easy of calculation the corresponding amount of pure tannin in the solution under examination4 #eie4 ,preparation of the ,tannin ,infusion4--,a sample weighing about a kilogram should be secured1 representing as nearly as possible the whole of the materials containing tannin in a given lot4 ,the sample is reduced to a fine powder and passed through a sieve containing apertures about a millimeter in diameter4 ,the quantity of the sample used for the extraction depends largely upon its content of tannin4 ,five grams of nutgalls1 ten grams of sumach or twenty grams of oak bark represent about the quantities necessary for these classes of tannin-holding materials4 ,the sample is boiled for half an hour with half a liter of water1 filtered through a linen bag into a liter flask and washed and pressed with enough water to make the volume of the filtrate equal to one liter4 ,the proper quantities of this solution are used for the analytical processes described above4 ,,tobacco4 #eif4 ,fermented and ,unfermented ,tobacco4--,samples of tobacco may reach the analyst either in the fermented or unfermented state4 ,as a basis for comparison1 it is advisable in all cases to determine the constituents of the sample before fermentation sets in4 ,the analysis1 after fermentation is complete1 will then show the changes of a chemical nature which it has undergone during the process of curing and sweating4 ,only tobacco which has undergone fermentation is found to be in a suitable condition for consumption4 ,in addition to the natural constituents of tobacco1 it may contain1 in the manufactured state1 flavoring ingredients such as licorice and sugar1 coloring matters and in some instances1 it is said1 opium or other stimulating drugs4 ,it is believed1 however1 that opium is not often found in manufactured tobacco1 and it has never been found in this laboratory in cigarettes1 although all the standard brands have been examined for it4#fad ,in researches made at the ,connecticut ,station it is shown that fermentation produces but little change in the relative quantities of nitric acid1 ammonia1 fiber and starch in the leaves1 while those of nicotin1 albuminoids and amids are diminished4 ,this is not in harmony with the generally accepted theory that starch is inverted and fermented during the process4#fae ,the nature of the ferments which are active in producing the changes which tobacco undergoes in curing1 is not definitely understood4 ,some of the organic constituents of the tobacco undergo a considerable change during the process4 ,any sugar which is found in the freshly cured leaves disappears wholly or in part4 ,as products of fermentation may also be found succinic1 fumaric1 formic1 acetic1 propionic and butyric acids4 #eig4 ,acid and ,basic ,constituents of ,tobacco4--,in unfermented and fermented tobacco are found certain organic acids1 among the most important of which are citric1 malic1 oxalic1 pectic and tannic4 ,of the inorganic acids the chief which are found are nitric1 sulfuric and hydrochloric4 ,among the bases ammonia and nicotin are the most important4 ,ammonia is found in the unfermented tobacco in only small quantities1 but in the fermented product it may sometimes reach as high as half a per cent4 ,the presence of these two nitrogenous bases in tobacco renders the estimation of the proteid matter contained therein somewhat tedious and difficult4 #eih4 ,composition of ,tobacco ,ash4--,the mineral constituents of tobacco are highly important from a commercial point of view4 ,the burning properties of tobacco depend largely upon the nature of its mineral constituents4 ,a sample containing a large quantity of chlorids burns much less freely than one in which the sulfates and nitrates predominate4 ,for this reason1 the use of potash fertilizers containing large amounts of chlorin is injudicious in tobacco culture1 the carbonates and sulfates of potash being preferred4 ,the leaves of the tobacco plant contain a much larger percentage of mineral constituents than the stems1 their respective contents of pure ash1 that is ash free from carbon dioxid1 carbon and sand1 being about seventeen and seven4 ,the pure ash of the leaves has the following mean composition3 ,potash #bi4a per cent1 soda #c4b per cent1 lime #cf4j per cent1 magnesia #g4d per cent1 iron oxid #b4j per cent1 phosphoric acid #d4g per cent1 sulfuric acid #f4j per cent1 silica #e4h per cent1 and chlorin #f4g per cent4#faf #eii4 ,composition of ,tobacco4--,the mean composition of some of the more important varieties of water-free tobacco is shown in the following table3#fag ,havana1 ,sumatra1 ,kentucky1 ,java1 per cent4 per cent4 per cent4 per cent4 ,nicotin #c4ih #b4ch #d4ei #c4cj ,malic acid #ab4aa #aa4aa #aa4eg #f4jd ,citric acid #b4je #b4ec #c4dj #c4cj ,oxalic acid #a4ec #b4ig #b4jc #c4ch ,acetic acid #j4db #j4bi #j4dc #j4bb ,tannic acid #a4ac #j4ih #a4dh #j4ea ,nitric acid #a4cb #j4fj #a4hh #j4bc ,pectic acid #aa4cf #aa4hh #h4bb #aj4ac ,cellulose #ae4gf #aj4ei #ab4dh #aa4hb ,ammonia #j4di #j4jf #j4ai #j4bc ,soluble nitrogenous matter #g4gd #h4hd #ac4ij #aj4ci ,insoluble 0 0 #i4ge #g4ig #h4aj #i4ec ,residue and chlorophyll #e4ae #h4fc #a4ii #f4de ,oil #a4jc #a4bf #b4bh #j4ha ,ash #ag4ej #ag4jc #ad4cf #ah4df ,undetermined #h4fh #ab4hh #ac4aj #ae4bj ,among the undetermined matters are included those of a gummy or resinous composition not extracted by ether1 the exact nature of which is not well understood1 and the starches1 sugars1 pentosans and galactan4 ,tobacco grown in more northern latitudes has less nicotin than the samples given in the foregoing table4 ,the following table shows the composition of tobacco grown in ,connecticut3#fah 7,a7 ,unfermented1 7,b7 ,fermented1 ,upper leaves4 ,short seconds4 ,first wrappers4 7,a7 7,b7 7,a7 7,b7 7,a7 7,b7 ,water #bc4ej #bc4dj #bg4dj #ba4aj #bg4ej #bd4ij ,pure ash #ad4hi #ae4bg #bb4he #be4be #ae4hd #af4bb ,nicotin #b4ej #a4gi #j4gg #j4ej #a4bf #a4dd ,nitric acid #a4hi #a4ig #b4ci #b4hb #b4ei #b4ce ,ammonia #j4fg #j4ga #j4af #j4af #j4cc #j4dg ,proteids #ab4ai #ac4ca #f4fi #f4ha #aa4ca #aa4fb ,fiber #g4ij #h4gh #g4hi #h4ie #i4ib #aj4db ,starch #c4bj #c4cf #b4fb #c4ja #b4hi #c4jh ,oil and fat #c4hg #c4db #b4ie #c4jd #b4hd #b4ib ,undeterm'd #bi4ci #bg4ii #bf4bh #bh4cf #be4eb #bf4hh #fjj4 ,estimation of ,water4--,in the estimation of water in vegetable substances1 as has already been noted1 it is usual to dry them in the air or partial vacuum1 or in an inert gas1 at a temperature of #ajj until a constant weight is reached4 ,by this process1 not only the water1 but all substances volatile at the temperature and in the conditions mentioned are expelled4 ,the quantity of these volatile substances in vegetable matter1 as a rule1 is insignificant and hence the total loss may be estimated as water4 ,in the case of tobacco a far different condition is presented1 inasmuch as the nicotin1 which sometimes amounts to five per cent of the weight of the sample1 is also volatile under the conditions mentioned4 ,it is advisable1 therefore1 to dry the sample of tobacco at a temperature not above fifty degrees and in a vacuum as complete as possible4 ,tobacco is also extremely rich in its content of crystallized mineral salts1 containing often water of crystallization1 and there is danger of this crystal water being lost when the sample is dried at #ajj4 ,the desiccation is conveniently made in the apparatus described on page #bb4 ,if a high vacuum be employed1 viz41 about twenty-five inches of mercury1 it is better not to allow the temperature to go above #dj or #de4 ,a rather rapid current of dry air should be allowed to pass through the apparatus for the more speedy removal of the moisture and a dish containing sulfuric acid may also be placed inside of the drying apparatus4 ,it is possible by proceeding in this way to secure constant weight in the sample after a few hours4 #fja4 ,estimation of ,nitric ,acid4--,the nitric acid in a sample of tobacco is most easily estimated by the ferrous chlorid process4#fai ,the sample is best prepared by making an alcoholic extract which is accomplished by exhausting about twenty-five grams of the fine tobacco powder with #bjj cubic centimeters for forty per cent alcohol made slightly alkaline by soda lye4 ,the mixture is boiled in a flask with a reflux condenser for about an hour4 ,after cooling1 the volume is completed to a definite quantity1 and1 after filtering1 an aliquot part is used for the analytical process4 ,it is evident that the nitric acid cannot be estimated in this case after previous reduction to ammonia by zinc or iron on account of the presence of ammonia in the sample itself4 ,if1 however1 the amount of ammonia be determined in a separate portion of the sample1 the nitric acid may be reduced in the usual way1 by zinc or iron1 the total quantity of ammonia determined by distillation1 the quantity originally present in the sample deducted and the residual ammonia calculated to nitric acid4 #fjb4 ,sulfuric and ,hydrochloric ,acids4--,these two acids are determined in the ash of the sample by the usual methods4 ,the sulfuric acid thus found represents the original sulfuric acid in combination with the bases in the mineral parts of the plant1 together with that produced by the oxidation of the organic sulfur during combustion4 ,in order to avoid all loss of sulfur during the combustion1 the precautions already given should be observed4 ,the separation of the sulfur pre-existing as sulfates from that converted into sulfates during the combustion is accomplished as previously directed4#fbj ,for ordinary purposes1 this separation is not necessary4 ,to avoid loss of chlorin from volatilization during incineration the temperature should be kept at the lowest possible point until the mass is charred1 the soluble salts extracted from the charred mass and the incineration completed as usual4 #fjc4 ,oxalic1 ,citric and ,malic ,acids4--,the separation and estimation of organic acids from vegetable tissues is a matter of great difficulty1 especially when they exist as is usually the case1 in very minute proportions4 ,during incineration1 the salts of the inorganic acids are converted into carbonates and the subsequent examination of the ash gives no indication of the character of the original acids4 ,in the case of tobacco1 the organic acids of chief importance1 from an analytical point of view1 are oxalic1 citric and malic4 ,these acids may be extracted and separated by the following process3#fba ,ten grams of the dry tobacco powder are rubbed up in a mortar with twelve cubic centimeters of dilute sulfuric acid 7one to five7 and then absorbed with coarse pumice stone powder in sufficient quantity to cause all the liquid to disappear4 ,the mass is placed in an extraction apparatus of proper size and thoroughly extracted with ether until a drop of the extract leaves no acid residue on evaporation4 ,usually about ten hours are required4 ,the organic acids are thus separated from the mineral acids4 ,the ether is removed from the extract and the residue dissolved in hot water1 cooled1 filtered1 if necessary several times1 until the solution is separated from the fat and resin which have been extracted by the ether4 ,the filtrate is neutralized with ammonia1 slightly acidified with acetic and the oxalic acid contained therein thrown out by means of a dilute solution of calcium acetate1 which must not be added in excess4 ,the calcium oxalate is separated by filtration1 and determined as lime oxid4 ,to the filtrate is added drop by drop1 with constant stirring1 a dilute solution of lead acetate1 prepared by mixing one part of a saturated solution of lead acetate with four parts of water4 ,when the precipitate formed has settled1 the clear supernatant liquid is tested by adding a drop of acetic acid and a few drops of the dilute lead acetate4 ,in case a precipitate be formed1 the addition of the lead acetate is continued until a precipitate is secured which will immediately dissolve in acetic acid4 ,at this moment the citric acid is almost completely precipitated4 ,in order to avoid the accumulation of the acetic acid by reason of the repetition of the process as above described1 the mixture is neutralized each time with dilute ammonia4 ,the precipitated neutral lead citrate obtained by the above process1 is separated by filtration and1 in order to avoid its decomposition when washed with pure water1 it is washed with a very dilute acetic acid solution of lead acetate4 ,the washing and filtration are accomplished as quickly as possible1 and the final washing is made with alcohol of thirty-six per cent strength4 ,in the filtrate the residual lead citrate1 together with a little lead malate1 are precipitated by the alcohol used as the wash and this precipitate is also separated by filtration4 ,the filtrate containing the greater part of the malic acid is evaporated to remove the alcohol and treated with lead acetate in excess4 ,afterwards it is mixed with five times its volume of thirty-six per cent alcohol containing a half per cent of acetic acid4 ,in these conditions the lead malate is completely precipitated as neutral salt1 and after standing a few hours1 is separated by filtration4 ,the three precipitates1 obtained as above1 are dried at #ajj and weighed4 ,if the precipitates have been collected on filter paper they should be removed as completely as possible1 the papers incinerated in the usual way and any reduced lead converted into nitrate and oxid by treatment with nitric acid and subsequent ignition4 ,from the quantities of lead oxid obtained1 the weights of the citric and malic acids are computed4 ,the precipitate which is obtained by the action of alcohol1 above noted1 is also dried and ignited and the lead oxid found divided equally between the citric and malic acids1 the respective quantities of which found1 are included in computing their total weights4 ,the weight of the citric acid is calculated from the formula 7,c,h,o7,pb ,h,o1 and that of the malic acid from the formula ,c,h,o,pb ,h,o4 #fjd4 ,acetic ,acid4--,for the determination of the volatile acids of the fatty series existing in tobacco1 the following process1 also due to ,schlsing1 may be followed3#fbb ,the apparatus employed is shown in ,fig4 #aba4 ,ten grams of the pulverized tobacco1 moistened with water and mixed with a little powdered tartaric acid1 are placed in the tube ,a4 ,the two ends of the tube1 ,a1 are stoppered with asbestos or glass wool4 ,steam1 generated in the flask1 ,d1 is passed into ,b4 ,after fifteen minutes1 or as soon as it is certain that the contents of ,a have reached a temperature of #ajj1 the dish1 ,f1 containing mercury1 is placed in the position shown in the figure4 ,the steam1 by this arrangement1 is forced into the lower end of ,a1 passes into the condenser ,e1 and the condensed water collected in ,c4 ,the operation should be so conducted as to avoid any condensation of water in ,b4 ,it is advisable during the progress of the distillation1 which should continue for at least twenty minutes1 to neutralize from time to time the acetic acid collected in ,c by a set solution of dilute alkali1 or1 an excess of the alkaline solution may be placed in ,c and the part not neutralized by the acetic acid determined at the end of the distillation by titration4 ,illustration3 ,,fig4 #aba4--;,,apparatus ,,for ,,acetic ,,acid4 #fje4 ,pectic ,acid4--,under this term are included not only the pectic acid but all the other bodies of a pectose nature contained in tobacco4 ,these bodies are of considerable interest1 although they do not belong to the most important constituents4 ,in fresh tobacco leaves are found three pectin bodies4 ,one pectin is soluble in water1 another is an insoluble pectose and the third is the pectose body forming salts with the alkalies1 i4 e41 true pectic acid4 ,in fermented tobacco pectic acid is found chiefly in combination with lime in the ribs of the leaves1 serving to give them the necessary stiffness4 ,for the estimation of the pectin bodies 7mucilage7 the powdered tobacco is thoroughly extracted with cold water4 ,an aliquot part of the aqueous extract is mixed with two volumes of strong alcohol and allowed to stand in a well closed vessel in a cool place for twenty-four hours4 ,the precipitate is collected on a filter1 washed with sixty-six per cent alcohol1 dried and weighed4 ,the dried residue is incinerated and the amount of ash determined4 ,in general1 vegetable mucilages contain about five per cent of ash4 ,if more than this be found1 it is due to the solution of the salts of the organic acids contained in the sample4 ,a dried vegetable mucilage1 obtained as above1 dissolves in water to a mucilaginous liquid which does not reduce alkaline copper solution until it has been hydrolyzed by boiling with a dilute mineral acid4#fbc #fjf4 ,tannic ,acid4--,this acid is separated and estimated by the processes given in paragraphs #ehi-eie4 #fjg4 ,starch and ,sugar4--,the unfermented leaves of tobacco contain considerable quantities of carbohydrates in addition to woody fiber1 pentosans1 galactan and cellulose4 ,among these1 starch is the most important4 ,sugar exists in small quantities in the fresh leaf1 usually not over one per cent4 ,during fermentation1 according to some authorities1 the starch is partially converted into sugar and the latter substance disappears under the action of the alcoholic ferments4 ,it has been found at the ,connecticut ,station1 however1 that the starch content of the leaf does not decrease during fermentation4 ,the starch and sugar may be determined in the fresh leaves by the methods already given4 ,in the manufacture of certain grades of tobacco it is customary to add a quantity of sugar4 ,the analyst may thus be called upon to determine in some cases whether the sugar found in a sample is natural or added4 ,the occurrence of natural sugars in tobacco has been investigated at the instance of the ,british ,treasury4#fbd ,the natural sugars which may be found in sun dried tobaccos usually disappear entirely during the process of fermentation4 ,it was found by the ,somerset ,house chemists that the content of sugar in commercial tobaccos varies from none at all to over fifteen per cent4 ,a remarkable example of this variation is reported in two samples from this country1 one of which1 grown in ,kentucky1 contained no sugar1 and the other grown in ,virginia1 #ae4b per cent4 ,it was noticed that the saccharin matters in the tobaccos examined were neutral to polarized light4 ,they are determined by their copper reducing power4 ,the tobacco sugars are therefore to be classed with the reducing bodies1 not optically active1 found in the juices of sorghum and sugar canes4 #fjh4 ,ammonia4--,as has already been intimated1 ammonia exists only in minute quantities in fresh tobacco leaves1 but in considerable quantities after fermentation4 ,in the estimation of ammonia1 twenty grams of the tobacco powder are digested with #bej cubic centimeters of water1 acidulated with sulfuric and after an hour enough water added to make the total quantity #djj cubic centimeters4 ,after filtration1 an aliquot part of the filtrate1 about #bjj cubic centimeters1 is treated with magnesium oxid in excess and the ammonia and nicotin removed by distillation in a current of steam4 ,the distillate is collected in dilute sulfuric acid of known strength4 ,the total amount of the two bases is determined by titration and the quantity of base representing the nicotin1 which has been determined in a separate sample1 subtracted in order to obtain the weight of the ammonia4#fbe ,the ammonia in tobacco is determined by ,nessler in the following manner3#fbf ,the powdered tobacco is mixed with water and magnesium oxid and after standing for several hours it is distilled in a current of steam1 the distillate received in dilute sulfuric acid and the process continued until a drop of the distillate gives no reaction for ammonia with the nessler reagent4 ,the excess of sulfuric acid in the distillate is neutralized with pure sodium carbonate and the nicotin precipitated by a neutral solution of mercuric iodid and potassium iodid4 ,the precipitate is separated by filtration1 the filtrate treated with sodium sulfid1 and the ammonia again obtained by distillation with an alkali1 collected in dilute solution of set sulfuric acid and determined by titration4 ,the difference of the two determinations represents the ammonia4 #fji4 ,nicotin4--,in this laboratory ,mc,elroy has made a study of some of the best approved methods for determining nicotin1 and finds the most simple and reliable to be that proposed by ,kissling4#fbg ,the finely powdered tobacco should be dried at a temperature not exceeding #fj1 or it may be partially dried at that temperature before grinding and the final drying completed afterwards4 ,twenty grams of the powdered sample are intimately mixed by means of a pestle with ten cubic centimeters of dilute alcoholic solution of soda lye1 made by dissolving six grams of sodium hydroxid in forty cubic centimeters of water and completing the volume to #ajj cubic centimeters with ninety-five per cent alcohol4 ,the mass is transferred to an extraction paper cylinder1 placed in an extraction apparatus and extracted for three hours with ether4 ,the ether is nearly all removed by careful distillation1 the residue mixed with fifty cubic centimeters of a very dilute soda lye solution 7#d to #ajj7 and subjected to distillation in a current of steam4 ,the flask containing the nicotin extract should be connected with the condensing apparatus by a safety bulb as is usual in the distillation of substances containing fixed alkali4 ,the distillation should be conducted rapidly and in such a manner that when #bjj cubic centimeters of the distillate have been collected1 not more than fifteen cubic centimeters of the liquid remain in the distillation flask4 ,in the distillate1 the nicotin is determined by titration with a set solution of dilute sulfuric acid1 using rosolic acid or phenacetolin as indicator4 ,it is advisable to titrate each fifty cubic centimeters of the distillate as it is received and the distillation is continued until the last fifty cubic centimeters give no appreciable quantity of the alkaloid4 ,in the calculations one molecule of sulfuric acid is equivalent to two molecules of nicotin according to the equation ,h,,so 7,c,h,n74 #ih #cbd ,polarization ,method4--,popovici has based a method of detecting the quantity of nicotin in tobacco on its property of rotating the plane of polarized light4#fbh ,the gyrodynat of pure nicotin is expressed by the formula a,d -#afa4f4 ,when ten parts of nicotin are mixed with ninety parts of water1 this value becomes -#gd4a4 ,by reason of this great depression in gyrodynatic value ,popovici determined the relation which exists between the dilute solutions of nicotin and the number of minutes of angular rotation produced on polarization in a #bjj millimeter tube4 ,in a solution in which two grams of nicotin are contained in fifty cubic centimeters1 each minute of angular rotation is found to correspond to #f4e milligrams of nicotin4 ,for one gram in solution in the same volume one minute of angular rotation corresponds to #e4i milligrams and for a half gram in solution to #e4g milligrams4 ,the nicotin is prepared for polarization by extracting with ether1 as indicated in the previous paragraph1 and the ethereal solution from twenty grams of tobacco is shaken with a concentrated solution of sodium phosphotungstate in nitric acid by means of which nicotin and ammonia are precipitated and rapidly settle4 ,the supernatant liquid is carefully poured off and the residue made up to a volume of fifty cubic centimeters with distilled water and the nicotin freed from any of its compounds by the addition of eight grams of finely powdered barium hydroxid4 ,in order to promote the decomposition of the nicotin compounds the mixture should be shaken at intervals for several hours4 ,the at first blue precipitate changes into blue green and finally into yellow4 ,it is separated by filtration and the somewhat yellow colored filtrate placed in an observation tube1 polarized1 the polarization calculated to minutes of angular rotation and the number of minutes thus found multiplied by the nearest factor given above4 ,the analyst will find a description of other methods of estimating nicotin in tobacco in the periodical literature of analytical chemistry4#fbi #faj4 ,estimation of ,amid ,nitrogen4--,for the estimation of amid nitrogen ten grams of the powdered tobacco are digested with #ajj cubic centimeters of forty per cent alcohol1 the extract separated by filtration1 acidified with sulfuric and the albumin1 peptone1 nicotin and ammonia precipitated with as little phosphotungstic acid as possible4 ,the precipitate is separated by filtration and seventy-five cubic centimeters of the filtrate evaporated in a thin glass or tin foil capsule after the addition of a little barium chlorid and the nitrogen determined in the residue4 ,the nitrogen thus obtained is that which was present in an amid state4 ,the nitrogen present as amids1 ammonia and nicotin subtracted from the total nitrogen leaves that present as protein4 #faa4 ,fractional ,extraction of ,tobacco4--,to determine the character of the soluble constituents of tobacco it is advisable to subject it to a fractional extraction with different reagents4 ,the reagents usually employed in the order mentioned are petroleum ether1 ether1 absolute alcohol1 water1 dilute soda lye and dilute hydrochloric acid4 ,the extract obtained by petroleum ether contains vegetable wax1 chlorophyll and its alteration products1 fat1 ethereal oils1 and resin bodies4 ,the extract with ether may be divided into water soluble and alcohol soluble bodies4 ,among the first are small quantities of glucosids and nicotin while in the alcoholic solution resin predominates4 ,the alcoholic extract is also divided into water soluble and alcohol soluble parts4 ,the first contains the nicotin1 which is insoluble in ether1 in combination with acids1 together with tannic acid and allied bodies and also the sugar4 ,the part insoluble in water consists chiefly of resin4 ,the aqueous solution contains the vegetable mucilages 7pectin7 soluble carbohydrates1 soluble proteids and organic acids4 ,the dilute soda lye solution contains chiefly proteids4 ,the dilute hydrochloric acid solution contains the starch and the oxalic acid originally combined with lime4 ,the extractions with dilute soda lye and dilute hydrochloric acid should be made at a boiling temperature4 ,the residual matter consists of a mixture of carbohydrate bodies to which the term crude fiber is usually applied4 #fab4 ,burning ,qualities4--,when tobacco is to be used for the manufacture of cigars1 or cigarettes1 or for smoking in pipes1 its ability to keep burning is a matter of great importance4 ,the tobacco1 when once ignited1 should burn for some time and form1 a fluffy ash1 free of fused mineral particles4 ,a tobacco with good burning properties is one containing nitrates in considerable quantity1 not too much sugar and starch1 a porous cellular structure and comparatively free of chlorin4 ,in determining comparative burning properties the tests may be applied to the single leaf or the tobacco may be first rolled into a cigar form and burned in an artificial smoker4 ,illustration3 ,,fig4 #abb4 ,,apparatus ,,for ,,smoking4 ,in applying the test to the leaf it is important that the ignition be made with a fuse without flame1 which maintains a uniform burning power4 ,any good slow burning fuse may be used and it is applied to the leaf in such a way that a hole may be burned in it1 leaving its edges uniformly ignited4 ,the number of seconds elapsing before the last spark is extinguished is noted4 ,at the ,connecticut ,experiment ,station a lighter1 proposed by ,nessler1 is employed4 ,it is prepared by digesting eighty grams of gum arabic in #abj cubic centimeters1 and forty grams of gum tragacanth in a quarter of a liter of water for two days1 mixing the mucilaginous masses and adding ten grams of potassium nitrate and about #cej grams of pulverized charcoal4 ,the mixture is rolled1 on a plate sprinkled with charcoal1 into sticks a few inches in length and of the diameter of a cigar and dried at a gentle heat4 ,these fuses burn slowly and without smoke and are well suited for lighting tobacco leaves4 ,several tests1 at least six1 should be made with each leaf4 ,leaves having a uniform burning power should be used as comparators and the number of seconds they burn be designated by #ajj4 ,it is important that all the samples to be tested be exposed for a day or two to the same atmosphere in order that they may have1 as nearly as possible1 the same content of moisture4 ,the burning tests1 when possible1 should be made both before and after fermentation4 ,as a rule fermentation improves the burning quality of second rate leaves1 but has little effect on leaves of the first quality4 #fac4 ,artificial ,smoker4--,for the purpose of comparing the burning properties of cigars1 or of leaves rolled into cigar form1 the artificial smoking apparatus devised by ,penfield and modified in this laboratory is employed4#fcj ,the construction of the apparatus is shown in the accompanying figure4 ,the lighted cigar is set in the tube at the left1 so that air entering the test-tube must pass through the cigar4 ,the test-tube contains enough water to seal the end of the tube carrying the cigar1 and is connected with the aspirator on the right by the ,t tube1 as shown4 ,an arm of the ,t dips just beneath the surface of the liquid in the cup in the center4 ,water flows in a slow stream into the aspirator through the tube at the extreme right1 forcing the air out through the arm of the ,t until the siphon begins to act4 ,while the water is voided through the long arm of the siphon1 air enters through the cigar1 the liquid rising in the ,t4 ,the action of the apparatus is automatic and intermittent4 ,when the cigar is about one-third burned1 it is removed without disturbing the ash cone1 and the latter examined and compared with other samples as a standard4 ,the sealing liquid of the long arm of the ,t may be mercury or water4 ,in case mercury be used1 care must be taken not to immerse the open end of the ,t more than one millimeter therein4 ,,fermented ,,beverages4 #fad4 ,description4--,among fermented beverages are included those drinks1 containing alcohol1 prepared by fermenting the sugars or starches of fruits1 cereals or other agricultural products4 ,wine and beer1 in their various forms1 and cider are the chief members of this class of bodies4 ,koumiss1 although a fermented beverage1 is not included in this classification1 having been noticed under dairy products4 ,the large number of artificial drinks1 made by mixing alcohol with fruit and synthesized essences1 is also excluded1 although the methods of analysis which are used may be applied also to them4 ,fermented beverages containing less than two per cent of alcohol are usually regarded as non-intoxicating drinks4 ,beers are of several varieties1 and the term includes lager beer1 ale1 porter and stout4 ,distilled liquors are obtained by separating the alcohols and other volatile matters from the products of fermentation by distillation4 ,it is not practicable here to attempt a description of the methods of preparing fermented drinks4 ,special works on this branch of the subject are easy of access4#fca #fae4 ,important ,constituents4--,alcohol is the most important constituent of fermented beverages4 ,the solid matters1 commonly called extract1 which are obtained on evaporation are composed of dextrins1 sugars1 organic acids1 nitrogenous bodies and mineral matters affording ash on combustion4 ,of these the dextrins and sugars form the chief part and the proteid bodies nearly ten per cent in the case of beers made of malt and hops4 ,in beers the bitter principles derived from hops1 while not important by reason of quantity1 are of the utmost consequence from a gustatory and hygienic point of view4 ,the ash of fermented beverages varies with their nature1 or with the character of the water used in making the mash4 ,in the manufacture of beer1 water containing a considerable proportion of gypsum is often used1 and this substance is sometimes added in the course of manufacture1 especially of wine4 ,the presence of common salt in the ash in any notable quantity is evidence of the addition of this condiment1 either to improve the taste of the beverage or to increase the thirst of the drinker4 ,in cider the organic acids1 especially malic1 are of importance4 ,glycerol is a product of fermentation and of the hydrolysis of the fats and oils in the substances fermented4 #faf4 ,specific ,gravity4--,in order to secure uniformity of expression1 the specific gravity of fermented beverages is determined at about #ae4f1 although that is a temperature much below the average found in ,american laboratories4 ,the specific gravity may be determined by an alcoholometer1 pyknometer or hydrostatic balance in harmony with the directions given in paragraphs #dh-ed and #bhe4 ,by reason of the extractive matters held in solution1 fermented beverages are usually heavier than water1 even if the content of alcohol be twenty per cent or more4 ,on the other hand distilled liquors are lighter than water4 #fag4 ,determination of ,alcohol4--,the determination of the percentage of alcohol present in a solution is based on two general principles4 ,on the one hand1 and this is the base of the methods in common use1 the alcohol is secured mixed only with water and its amount determined by ascertaining the specific gravity of the mixture4 ,on the other hand the quantity of alcohol in a mixture may be determined by ascertaining the temperature of the vapors produced on boiling4 ,this is the principle involved in the use of the ebullioscope4 ,the latter method is not employed to any extent in this country4 ,use of the ,alcoholometer4--,the alcoholometer usually employed is known by the name of ,gay-,lussac1 who first made practical use of it in the determination of alcohol4 ,it is constructed in such a way as to read directly the volume of absolute alcohol contained in one hundred volumes of the liquid at a temperature of #ae4f4 ,the instruments employed should be carefully calibrated and thoroughly cleaned by washing with absolute alcohol before use4 ,the stem of the instrument must be kept free from any greasy substance1 and this is secured by washing it with ether4 ,after this last washing the analyst should be careful not to touch the stem of the instrument with his fingers4 ,it is most convenient to make the determination exactly at #ae4f1 but when made at other temperatures the reading of the instrument is corrected by tables which may be found in works especially devoted to the analysis of wines4#fcb ,in this country the alcoholometer is used to some extent1 but the official method is based upon the determination of the specific gravity by an instrument constructed in every respect like the alcoholometer1 but giving the specific gravity of the liquor at #ae4f instead of its percentage by volume in alcohol4 ,the reading of the instrument having been determined at a temperature of #ae4f1 the corresponding percentage of alcohol by volume or by weight is taken directly from the table given further on4 ,illustration3 ,,fig4 #abc4 ,,metal ,,distilling ,,apparatus4 ,methods of ,distillation4--,the metal apparatus employed in the laboratory of the ,department of ,agriculture1 for the distillation of fermented beverages in order to determine the percentage of alcohol by the method given above1 is shown in the accompanying figure4 ,the apparatus consists of a retort of copper carried on supports in such a way as to permit an alcohol or bunsen lamp to be placed under it4 ,it is connected with a block tin condenser and the distillate is received in a tall graduated cylinder placed under the condenser in such a way as to prevent the loss of any alcohol in the form of vapor4 ,exactly #cjj cubic centimeters of the wine or fermented beverage are used for the distillation4 ,any acid which the wine contains is first saturated with calcium carbonate before placing in the retort4 ,exactly #ajj cubic centimeters of distillate are collected and the volume of the distillate is completed to #cjj cubic centimeters by the addition of recently distilled water4#fcc ,the cylinder containing the distillate is brought to a temperature of #ae4f1 the alcoholometer inserted and its reading taken with the usual precautions4 ,official ,method4--,the alcoholometers employed in the official methods are calibrated to agree with those used by the officers of the ,bureau of ,internal ,revenue4 ,they are most conveniently constructed1 carrying the thermometer scale in the same stem with that showing the specific gravity4 ,it is highly important that the analyst assure himself of the exact calibration of the instrument before using it4 ,inasmuch as the volume of the distillate may not be suited in all cases to the use of a large alcoholometer1 it is customary in this laboratory to determine the specific gravity by means of the hydrostatic balance1 as described further on4 ,attention is also called to the fact that1 in the official method1 directions are not given to neutralize the free acid of the fermented beverage before the distillation4 ,since the ,internal ,revenue ,bureau is concerned chiefly with the determination of alcohol in distilled liquors1 this omission is of little consequence4 ,even in ordinary fermented beverages the percentage of volatile acids1 7acetic etc417 is so small as to make the error due to the failure to neutralize it of but little consequence4 ,in order1 however1 to avoid every possibility of error1 it is recommended that in all instances the free acids of the sample be neutralized before distillation4 ,in this laboratory1 the distillations are conducted in a glass apparatus shown in the accompanying figure4 ,the manipulation is as follow3#fcd ,illustration3 ,,fig4 #abd4 ,,distilling ,,apparatus4 ,one hundred cubic centimeters of the liquor are placed in a flask of from #bej to #cjj cubic centimeters capacity1 fifty cubic centimeters of water added1 the flask attached to a vertical condenser by means of a bent bulb tube1 #ajj cubic centimeters distilled and the specific gravity of the distillate determined4 ,the distillate is also weighed1 or its weight calculated from the specific gravity4 ,the corresponding percentage of alcohol by weight is obtained from the appended table1 and this figure multiplied by the weight of the distillate1 and the result divided by the weight of the sample1 gives the per cent of alcohol by weight contained therein4 ,the percentage of alcohol by volume of the liquor is the same as that of the distillate1 and is obtained directly from the appended table4 ,in distilled liquors about thirty grams are diluted to #aej cubic centimeters1 #ajj cubic centimeters distilled and the per cent of alcohol by weight determined as above4 ,the percentage of alcohol by volume in the distillate is obtained from the appended table4 ,this figure divided by the number expressing the volume in cubic centimeters of the liquor taken for the determination 7calculated from the specific gravity71 and the result multiplied by #ajj gives the per cent of alcohol by volume in the original liquor4 #fah4 ,determining the ,specific ,gravity of the ,distillate4--,the specific gravity of the distillate may be determined by the pyknometer1 alcoholometer1 hydrostatic balance or in any accurate way4 ,the volume of the distillate is not always large enough to be conveniently used with an alcoholometer1 especially the large ones employed by the ,bureau of ,internal ,revenue4 ,in the laboratory of the ,agricultural ,department1 it is customary to determine the density of the distillate by the hydrostatic balance shown in paragraph #bhe4 ,the specific gravity is in each case determined at #ae4f1 referred to water of the same temperature1 or if at a different temperature calculated thereto4 #fai4 ,table for ,use with ,hydrostatic ,plummet4--,it is more convenient to determine the density of the alcoholic distillate at room temperature than to reduce it to the standard for which the plummet is graduated4 ,in the case of a plummet which displaces exactly five grams1 or multiple thereof1 of distilled water at #ae4f1 the corrections for temperatures between #ab4b and #cj are found in the following table1 prepared by ,bigelow4#fce ,if the weight of the alcoholic solution displaced be #d4ifjge grams the apparent specific gravity #j4iibae and the temperature of observation #be4d1 the correction1 which is additive1 as given in the table is #j4jjaia and the true specific gravity is #j4iidjf and the percentage of alcohol by volume #d4jh4 ,when the plummet does not exactly displace five grams of water at #ae4f1 but nearly so1 the table may still be used4 ,for example1 suppose the weight of water displaced be #d4ihfh instead of five grams4 ,the apparent specific gravity of the water by this plummet is #j4iigcf and the difference between this and the true specific gravity is #j4jjbfd1 which is a constant correction to be added to the specific gravity as determined in each case4 ,,correction ,,table ,,for ,,specific ,,gravity4 ,below #ae4f ,subtract2 ,above #ae4f ,add4 ,temp4 ,correction4 ,temp4 ,correction4 ,temp4 ,correction4 #ab4b #j4jjjdg #ah4b #j4jjjdc #bd4b #j4jjafc #ab4d #j4jjjdd #ah4d #j4jjjdf #bd4d #j4jjafg #ab4f #j4jjjdb #ah4f #j4jjjej #bd4f #j4jjagb #ab4h #j4jjjci #ah4h #j4jjjec #bd4h #j4jjagf #ac4j #j4jjjcg #ai4j #j4jjjeg #be4j #j4jjaha #ac4b #j4jjfcd #ai4b #j4jjjfa #be4b #j4jjahf #ac4d #j4jjjcb #ai4d #j4jjjfe #be4d #j4jjaia #ac4f #j4jjjbi #ai4f #j4jjjfh #be4f #j4jjaie #ac4h #j4jjjbg #ai4h #j4jjjgb #be4h #j4jjbjj #ad4j #j4jjjbd #bj4j #j4jjjgf #bf4j #j4jjbje #ad4b #j4jjjba #bj4b #j4jjjhj #bf4b #j4jjbaj #ad4d #j4jjjah #bj4d #j4jjjhd #bf4d #j4jjbae #ad4f #j4jjjae #bj4f #j4jjjhg #bf4f #j4jjbbj #ad4h #j4jjjab #bj4h #j4jjjia #bf4h #j4jjbbe #ae4j #j4jjjji #ba4j #j4jjjie #bg4j #j4jjbcj #ae4b #j4jjjjf #ba4b #j4jjjii #bg4b #j4jjbce #ae4d #j4jjjjc #ba4d #j4jjajc #bg4d #j4jjbdj #ae4f #j4jjjjj #ba4f #j4jjajg #bg4f #j4jjbdf #ae4h #j4jjjjc #ba4h #j4jjaaa #bg4h #j4jjbea #af4j #j4jjjjf #bb4j #j4jjaae #bh4j #j4jjbef #af4b #j4jjjji #bb4b #j4jjaai #bh4b #j4jjbfa #af4d #j4jjjab #bb4d #j4jjabc #bh4d #j4jjbfg #af4f #j4jjjaf #bb4f #j4jjabh #bh4f #j4jjbgb #af4h #j4jjjai #bb4h #j4jjacb #bh4h #j4jjbgh #ag4j #j4jjjbb #bc4j #j4jjacf #bi4j #j4jjbhc #ag4b #j4jjjbe #bc4b #j4jjadj #bi4b #j4jjbhh #ag4d #j4jjjbi #bc4d #j4jjade #bi4d #j4jjbid #ag4f #j4jjjcb #bc4f #j4jjadi #bi4f #j4jjbii #ag4h #j4jjjcf #bc4h #j4jjaed #bi4h #j4jjcjf #ah4j #j4jjjci #bd4j #j4jjaeh #cj4j #j4jjcaa ,the table is only accurate when the distillate does not contain over seven nor less than three per cent of alcohol4 ,if the distillate contain more than seven per cent of alcohol it is diluted and the compensating correction made4 #fbj4 ,calculating ,results4--,the specific gravity of the alcoholic distillate having been determined by any approved method and corrected to a temperature of #ae4f1 the corresponding per cents of alcohol by volume and by weight are found by consulting the following table4#fcf ,if1 for example1 the corrected specific gravity be exactly that given in any figure of the table the corresponding per cents are directly read4 ,if the specific gravity found fall between two numbers in the table the corresponding per cents are determined by interpolation4 ,,table ,,showing ,,percentage ,,of ,,alcohol ,,by ,,weight ,,and ,,by ,,volume4 ---------------------------------------- ------ ,specific ,per cent ,per cent gravity at alcohol alcohol #ae4f_/ae4f4 by volume4 by weight4 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4#iedhg #ch4jj #ca4eh #dhj 4#je 4#fc #dgb 4#aj 4#fg #dfe 4#ae 4#gb #deg 4#bj 4#gf #dej 4#be 4#ha #ddb 4#cj 4#he #dce 4#ce 4#ij #dbg 4#dj 4#id #dbj 4#de 4#ii 4#iedac #ch4ej #cb4jc #dje 4#ee 4#jg #cih 4#fj 4#ab #cij 4#fe 4#af #chc 4#gj 4#bj #cge 4#ge 4#be #cfh 4#hj 4#bi #cfj 4#he 4#cc #cec 4#ij 4#cg #cde 4#ie 4#db 4#iecch #ci4jj #cb4df #ccj 4#je 4#ej #cbc 4#aj 4#ee #cae 4#ae 4#ei #cjg 4#bj 4#fd #cjj 4#be 4#fh #bib 4#cj 4#gb #bhd 4#ce 4#gg #bgg 4#dj 4#ha #bfi 4#de 4#hf 4#iebfb #ci4ej #cb4ij #bed 4#ee 4#ie #bdf 4#fj 4#ii #bci 4#fe #cc4jd #bca 4#gj 4#jh #bbc 4#ge 4#ac #baf 4#hj 4#ag #bjh 4#he 4#bb #bjj 4#ij 4#bg #aic 4#ie 4#ca #j4ieahe #dj4jj #cc4ce #agg 4#je 4#ci #afi 4#aj 4#dd #afa 4#ae 4#dh #aed 4#bj 4#ec #adf 4#be 4#eg #ach 4#cj 4#fa #acj 4#ce 4#ff #abb 4#dj 4#gj #aad 4#de 4#ge 4#ieajg #dj4ej #cc4gi #jii 4#ee 4#hd #jia 4#fj 4#hh #jhc 4#fe 4#ic #jge 4#gj 4#ig #jfg 4#ge #cd4jb #jei 4#hj 4#jf #jeb 4#he 4#aa #jdd 4#ij 4#ae #jcf 4#ie 4#bj 4#iejbh #da4jj #cd4bd #jbj 4#je 4#bh #jab 4#aj 4#cc #jjd 4#ae 4#cg 4#idiif 4#bj 4#db #ihh 4#be 4#df #ihj 4#cj 4#ej #igb 4#ce 4#ee #ifd 4#dj 4#ei #ief 4#de 4#fd 4#ididh #da4ej #cd4fh #idj 4#ee 4#gc #icb 4#fj 4#gg #ibd 4#fe 4#hb #iaf 4#gj 4#hf #ijh 4#ge 4#ia #ijj 4#hj 4#ie #hib 4#he #ce4jj #hhd 4#ij 4#jd #hgf 4#ie 4#ji 4#idhfh #db4jj #ce4ac #hfj 4#je 4#ah #heb 4#aj 4#bb #hdc 4#ae 4#bg #hce 4#bj 4#ca #hbg 4#be 4#cf #hbj 4#cj 4#dj #haa 4#ce 4#de #hjb 4#dj 4#di #gid 4#de 4#ed #j4idghf #db4ej #ce4eh #ggh 4#ee 4#fc #ggj 4#fj 4#fg #gfa 4#fe 4#gb #gec 4#gj 4#gf #gde 4#ge 4#ha #gcg 4#hj 4#he #gbi 4#he 4#ij #gbj 4#ij 4#id #gab 4#ie 4#ii 4#idgjd #dc4jj #cf4jc #fif 4#je 4#jh #fhg 4#aj 4#ab #fgi 4#ae 4#ag #fgj 4#bj 4#ba #ffb 4#be 4#bc #fed 4#cj 4#cj #fde 4#ce 4#ce #fcg 4#dj 4#ci #fbh 4#de 4#dd 4#idfbj #dc4ej #cf4dh #fab 4#ee 4#ec #fjc 4#fj 4#eg #eie 4#fe 4#fb #ehf 4#gj 4#ff #egh 4#ge 4#ga #egj 4#hj 4#ge #efa 4#he 4#hj #eec 4#ij 4#hd #edd 4#ie 4#hi 4#idecf #dd4jj #cf4ic #ebg 4#je 4#ih #eai 4#aj #cg4jb #eaj 4#ae 4#jg #ejb 4#bj 4#aa #dic 4#be 4#af #dhd 4#cj 4#ba #dgf 4#ce 4#be #dfg 4#dj 4#cj #dei 4#de 4#cd 4#iddej #dd4ej #cg4ci #dda 4#ee 4#dd #dcc 4#fj 4#dh #dbd 4#fe 4#ec #daf 4#gj 4#eg #djg 4#ge 4#fb #cih 4#hj 4#ff #cij 4#he 4#ga #cha 4#ij 4#gf #cgc 4#ie 4#hj #j4idcfd #de4jj #cg4hd #cee 4#je 4#hi #cdf 4#aj 4#ic #cch 4#ae 4#ih #cbi 4#bj #ch4jb #cbj 4#be 4#jg #caa 4#cj 4#ab #cjb 4#ce 4#af #bid 4#dj 4#ba #bhe 4#de 4#be 4#idbgf #de4ej #ch4cj #bfg 4#ee 4#ce #beh 4#fj 4#ci #bej 4#fe 4#dd #bda 4#gj 4#dh #bcb 4#ge 4#ec #bbc 4#hj 4#eg #bad 4#he 4#fb #bjf 4#ij 4#ff #aig 4#ie 4#ga 4#idahh #df4jj #ch4ge #agi 4#je 4#hj #agj 4#aj 4#hd #afa 4#ae 4#hi #aeb 4#bj 4#ic #adc 4#be 4#ih #acd 4#cj #ci4jc #abe 4#ce 4#jg #aaf 4#dj 4#ab #ajg 4#de 4#af 4#idjih #df4ej #ci4ba #jhi 4#ee 4#bf #jhj 4#fj 4#cj #jga 4#fe 4#ce #jfb 4#gj 4#ci #jec 4#ge 4#dd #jdd 4#hj 4#di #jce 4#he 4#ec #jbf 4#ij 4#eh #jag 4#ie 4#fb 4#idjjh #dg4jj #ci4fg 4#iciii 4#je 4#gb #iij 4#aj 4#gf #ihj 4#ae 4#ha #iga 4#bj 4#he #ifb 4#be 4#ij #iec 4#cj 4#ie #idd 4#ce 4#ii #icd 4#dj #dj4jd #ibe 4#de 4#jh #j4iciaf #dg4ej #dj4ac #ijf 4#ee 4#ah #hih 4#fj 4#bb #hhh 4#fe 4#bg #hgi 4#gj 4#cb #hgj 4#ge 4#cg #hfa 4#hj 4#da #heb 4#he 4#df #hdb 4#ij 4#ea #hcc 4#ie 4#ee 4#ichbd #dh4jj #dj4fj #hae 4#je 4#fe #hjh 4#aj 4#fi #gif 4#ae 4#gd #ghf 4#bj 4#gh #ggg 4#be 4#hc #gfh 4#cj 4#hh #geh 4#ce 4#ib #gdj 4#dj 4#ig #gci 4#de #da4ja 4#icgcj #dh4ej #da4jf #gba 4#ee 4#aa #gaa 4#fj 4#ae #gjb 4#fe 4#bj #fib 4#gj 4#bd #fhc 4#ge 4#bi #fgc 4#hj 4#cd #ffd 4#he 4#ch #fee 4#ij 4#dc #fde 4#ie 4#dg 4#icfcf #di4jj #da4eb #fbf 4#je 4#eg #fag 4#aj 4#fa #fjg 4#ae 4#ff #eih 4#bj 4#ga #ehh 4#be 4#gf #egh 4#cj 4#hj #efi 4#ce 4#he #eei 4#dj 4#ij #eej 4#de 4#id 4#icedj #di4ej #da4ii #ecj 4#ee #db4jd #eba 4#fj 4#jh #eaa 4#fe 4#ac #ejb 4#gj 4#ah #dib 4#ge 4#bc #dhb 4#hj 4#bg #dgc 4#he 4#cb #dfc 4#ij 4#cg #ded 4#ie 4#da ---------------------------------------- --------- #fba4 ,determination of ,percentage of ,alcohol by ,means ,of ,vapor ,temperature4--,the temperature of a mixture of alcohol and water vapors is less than that of water alone and the depression is inversely proportional to the quantity of alcohol present4 ,this principle is utilized in the construction of the ebullioscope or ebulliometer4 ,in this apparatus the temperature of pure boiling water vapor is determined by a preliminary experiment4 ,this point must be frequently revised in order to correct it for variations in barometric pressure4 ,the water is withdrawn from the boiler of the apparatus1 the same volume of a wine or beer placed therein1 and the vapor temperature again determined4 ,by comparing the boiling point of the wine1 with a scale calibrated for different percentages of alcohol1 the quantity of spirit present is determined4 ,when water vapor is at #ajj a vin ordinaire having eight per cent of alcohol gives a vapor at #ic4h4 ,the presence of extractive matters in the sample1 which tend to raise its boiling point1 is neglected in the calculation of results4 #fbb4 ,improved ,ebullioscope4--,the principle mentioned in the above paragraph may be applied with a considerable degree of accuracy1 by using the improved ebullioscope described below4#fcg ,the apparatus consists of a glass flask ,f1 shaped somewhat like an erlenmeyer1 closed at the top with a rubber stopper carrying a central aperture for the insertion of the delicate thermometer ,a ,b1 and a lateral smaller aperture for connecting the interior of the flask with the condenser ,d4 ,the return of the condensed vapors from ,d is effected through the tube entering the flask ,f in such a manner as to deliver the condensed liquid beneath the surface of the liquid in ,f as shown in the figure4 ,the flask ,f contains pieces of scrap platinum or pumice stone to prevent bumping and secure an even ebullition4 ,the flask ,f rests upon a disk of asbestos1 perforated in such a way as to have the opening fully covered by the bottom of the flask4 ,to protect ,f against the influence of air currents it is enclosed in the glass cylinder ,e resting on the asbestos disk below and closed with a detachable soft rubber cover at the top4 ,the temperature between the cylinder ,e and the flask ,f is measured by the thermometer ,c and the flame of the lamp ,g should be so adjusted as to bring the temperature between the flask ,f and the cylinder ,e to about #ij at the time of reading the thermometer ,b4 ,the bulb of the thermometer ,b may be protected by a thin glass tube carrying distilled water1 so adjusted as to prevent the escape of the watery vapor into ,f4 ,the thermometer ,b is such as is used for determining molecular weights by the cryoscopic method4 ,it has a cistern at ,a which holds any excess of mercury not needed in adjusting the thermometer for any required temperature4 ,illustration3 ,,fig4 #abe4 ,,improved ,,ebullioscope4 ,a second apparatus1 exactly similar to the one described1 is conveniently used for measuring the changes in barometric pressure during the process of the analysis4 ,the temperature of the vapor of boiling water having been first determined1 the beer or wine is placed in ,f1 and the temperature of the vapor of the boiling liquid determined after the temperature of the air layer between ,e and ,f reaches about #ij1 measured on the thermometer ,c4 ,by using alcoholic mixtures of known strength the depression for each changing per cent of alcohol is determined for each system of apparatus employed1 and this having once been done1 the percentage of alcohol in any unknown liquid is at once determined by inspecting the thermometer1 the bulb of which is immersed in the vapor from the boiling liquid4 ,in the apparatus figured1 a depression of #j4h is equivalent to one per cent of alcohol by volume4 ,full directions for the manipulation of the apparatus may be found in the paper cited above4 #fbc4 ,total ,fixed ,matters4--,the residue left on evaporating a fermented beverage to dryness is commonly known as extractive matter1 or simply extract4 ,it is composed chiefly of unfermented carbohydrates1 organic acids1 nitrogenous bodies1 glycerol and mineral substances4 ,hydrochloric and sulfuric acids may also be found therein4 ,if any non-volatile preservatives have been used in the sample1 such as borax1 salicylates and the like1 these will also be found in the solid residue4 ,the bodies which escape are water1 alcohols1 ethers and essential oils4 ,the character of the residue left by wines and beers is evidently different4 ,in each case it should contain typical components which aid in judging of the purity of the sample4 ,for instance1 in beers the substitution for malt of carbohydrate bodies comparatively free of proteids1 produces a beer containing a deficiency of nitrogenous bodies4 ,pure malt beer will rarely have less than one-half of a per cent of proteids1 while beer made largely of glucose1 rice or hominy grits1 will have a much smaller quantity4 ,first will be described below the methods of determining the fixed residue left on evaporation1 and thereafter the processes for ascertaining its leading components4 #fbd4 ,methods of the ,official ,chemists4--,two methods are in use by the official chemists for determining the fixed solids in fermented beverages4#fch ,they are as follows3 ,direct ,method4--,fifty cubic centimeters of the sample are weighed1 placed in a platinum dish about eighty millimeters in diameter and capable of holding about seventy-five cubic centimeters and evaporated on the steam bath to a sirupy consistence4 ,the residue is heated for two and a half hours in a drying oven at the temperature of boiling water and weighed4 ,in ,sweet ,wines4--,ten cubic centimeters of the liquor are weighed and diluted to #ajj with water4 ,fifty cubic centimeters of this solution are evaporated as described above4 ,optional ,method4--,fifty cubic centimeters of the sample are placed in a platinum or porcelain dish and evaporated on the steam bath until the volume is reduced to one-third4 ,the dealcoholized liquid is washed into a fifty cubic centimeter flask1 cooled and made up to the original volume4 ,it is mixed thoroughly and the specific gravity ascertained with a pyknometer1 hydrostatic balance or an accurately standardized hydrometer4 ,the percentage of total solids is obtained from the appended table4 ,the column on the left of the specific gravity gives the percentage of extract in a wine1 as calculated by ,hager1 and that on the right the percentage of extract in a beer or wort1 as calculated by ,schultze4 ,according to ,baumert1 however1 ,schultze's table gives results which approximate more closely the data obtained by direct estimation than does ,hager's4 ,,tables ,,of ,,hager ,,and ,,schultze ,,for ,,the ,,determination ,,of ,,extract ,,by ,,the ,,indirect ,,method4 ,hager4 ,specific gravity4 ,schultze4 ----------------------------------- #j4hd #a4jjch #a4jj #j4hf #a4jjci #a4jb #j4hh #a4jjdj #a4je #j4ij #a4jjda #a4jh #j4ib #a4jjdb #a4aj #j4id #a4jjdc #a4ac #j4if #a4jjdd #a4ae #j4ih #a4jjde #a4ah #a4jj #a4jjdf #a4ba #a4jb #a4jjdg #a4bc #a4jd #a4jjdh #a4bf #a4jf #a4jjdi #a4bi #a4jh #a4jjej #a4ca #a4aj #a4jjea #a4cd #a4ab #a4jjeb #a4cf #a4ae #a4jjec #a4ci #a4ag #a4jjed #a4da #a4ai #a4jjee #a4dd #a4bb #a4jjef #a4df #a4be #a4jjeg #a4di #a4bg #a4jjeh #a4ea #a4cj #a4jjei #a4ed #a4cb #a4jjfj #a4ef #a4cd #a4jjfa #a4ei #a4cg #a4jjfb #a4fb #a4ci #a4jjfc #a4fd #a4db #a4jjfd #a4fg #a4dd #a4jjfe #a4fi #a4df #a4jjff #a4gb #a4dh #a4jjfg #a4gd #a4ej #a4jjfh #a4gg #a4eb #a4jjfi #a4gi #a4ee #a4jjgj #a4hb #a4eg #a4jjga #a4hd #a4ei #a4jjgb #a4hg #a4fa #a4jjgc #a4ij #a4fd #a4jjgd #a4ib #a4ff #a4jjge #a4ie #a4fh #a4jjgf #a4ig #a4gj #a4jjgg #b4jj #a4gb #a4jjgh #b4jb #a4ge #a4jjgi #b4je #a4gg #a4jjhj #b4jg #a4gi #a4jjha #b4aj #a4hb #a4jjhb #b4ab #a4hd #a4jjhc #b4ae #a4hf #a4jjhd #b4ag #a4hh #a4jjhe #b4bj #a4ij #a4jjhf #b4bc #a4ib #a4jjhg #b4be #a4id #a4jjhh #b4bh #a4if #a4jjhi #b4cj #a4ih #a4jjij #b4cc #b4jj #a4jjia #b4ce #b4jc #a4jjib #b4ch #b4je #a4jjic #b4da #b4jg #a4jjid #b4dc #b4ji #a4jjie #b4df #b4aa #a4jjif #b4dh #b4ad #a4jjig #b4ea #b4af #a4jjih #b4ec #b4ah #a4jjii #b4ef #b4ba #a4jajj #b4eh #b4bc #a4jaja #b4fa #b4be #a4jajb #b4fd #b4bg #a4jajc #b4ff #b4cj #a4jajd #b4fi #b4cb #a4jaje #b4ga #b4cd #a4jajf #b4gd #b4cf #a4jajg #b4gf #b4ch #a4jajh #b4gi #b4dj #a4jaji #b4hb #b4db #a4jaaj #b4hd #b4dd #a4jaaa #b4hg #b4df #a4jaab #b4hi #b4dh #a4jaac #b4ib #b4ej #a4jaad #b4id #b4eb #a4jaae #b4ig #b4ed #a4jaaf #b4ii #b4eg #a4jaag #c4jb #b4ei #a4jaah #c4je #b4fa #a4jaai #c4jg #b4fd #a4jabj #c4aj #b4ff #a4jaba #c4ab #b4fh #a4jabb #c4ae #b4gj #a4jabc #c4ag #b4gb #a4jabd #c4bj #b4ge #a4jabe #c4bc #b4gg #a4jabf #c4be #b4gi #a4jabg #c4bh #b4hb #a4jabh #c4cj #b4hd #a4jabi #c4cc #b4hf #a4jacj #c4ce #b4hh #a4jaca #c4ch #b4ij #a4jacb #c4da #b4ib #a4jacc #c4dc #b4id #a4jacd #c4df #b4if #a4jace #c4dh #b4ih #a4jacf #c4ea #c4jj #a4jacg #c4ed ,if it be desired to use this table for the examination of liquors containing a higher percentage of extract1 ,schultze's table 7intended originally for wort7 may be consulted4 ,gautier regards the fixed solids as the residue obtained on evaporating1 in a flat platinum dish1 ten cubic centimeters of wine at #ajj for four hours and a half4#fci ,the official ,french method is as follows3 ,twenty cubic centimeters of wine are placed in a flat bottom1 platinum dish of such a diameter that the depth of the liquid therein does not exceed one millimeter4 ,the dish should be immersed as totally as possible in the steam4 ,the heating is continued for six hours4 ,the following method is used at the municipal laboratory of ,paris3 ,twenty-five cubic centimeters of wine are placed in a flat bottom1 platinum dish seventy millimeters in diameter and twenty-five deep4 ,the dish is placed on a water bath in such a manner that it just touches the surface of the water which is kept at a constant level4 ,the heating is continued for seven hours4#fdj #fbe4 ,determination in a ,vacuum4--,to avoid the changes and decomposition produced by heating1 the fixed solids may also be determined by drying the sample in a vacuum over sulfuric acid4 ,in this laboratory1 it has been found that the process may be greatly facilitated by connecting the desiccating apparatus with the vacuum service of the working desks in which a vacuum corresponding to a mercurial column of #fjj millimeters is obtained4 ,the desiccator is provided with a valve whereby a minute current of dry air is allowed to flow through it4 ,this current is not large enough to lessen the vacuum but is sufficient to greatly accelerate the rapidity of the evaporation4 ,the evaporation is hastened also1 in a marked degree1 by absorbing the liquid with a piece of filter paper previously dried in a vacuum4 ,when it is desired to examine the residue1 however1 it must be obtained in a flat dish exposing a large surface to evaporation4 #fbf4 ,estimation of ,water4--,it is evident that the percentage of water in a fermented beverage is easily calculated when the percentage of alcohol by weight and that of the dry residue are known4 ,in a given case1 if the number of grams of alcohol in #ajj of the sample be five and that of fixed solids four and a half1 the quantity of water therein is #ajj - 7#e4j #d4e7 #ij4e grams4 ,in this case the volatile essences are counted as water1 but these1 at most1 are so small in quantity as to be practically unweighable4 ,nevertheless1 it must be admitted that direct drying1 in many cases1 may give erroneous results1 especially when the sample contains an abundance of ethers and of glycerol4 ,the loss which takes place on evaporation may be diminished by adding to the sample1 before evaporation1 a known weight of potassium sulfate in crystals1 which serves to increase the surface of evaporation1 to hasten the process and to obtain a quantity of residue in excess of that secured by direct evaporation in an open dish4 #fbg4 ,total ,acidity4--,the acidity found in fermented beverages is due both to the natural acids of the materials from which they are made1 and to those caused by fermentation4 ,the typical acids also indicate the nature of the original materials1 as malic in cider and tartaric in wine4 ,the acids of beers are due almost exclusively to fermentation1 and acetic is probably the dominant one4 ,in determining total acidity1 it is not always convenient to ascertain beforehand what acid predominates1 nor to accurately distribute the acid among its various components4 ,in the analytical work it is advisable1 therefore1 to estimate the total acid of cider as malic1 of wines as tartaric and of beers as acetic4 ,the process of titration is conducted as follows3 ,expel any carbon dioxid that is present by continued shaking4 ,transfer ten cubic centimeters to a beaker and1 in the case of white wines1 add about ten drops of a neutral litmus solution4 ,add decinormal sodium hydroxid solution until the red color changes to violet4 ,then add the reagent1 a few drops at a time1 until a drop of the liquid1 placed on delicate red litmus paper1 shows an alkaline reaction4 ,one cubic centimeter of decinormal sodium hydroxid solution #j4jjge gram tartaric1 #j4jjfg of malic and #j4jjf gram of acetic acid4 #fbh4 ,determination of ,volatile ,acids4--,fifty cubic centimeters of the sample1 to which a little tannin has been added to prevent foaming1 are distilled in a current of steam4 ,the flask is heated until the liquid boils1 when the lamp under it is turned down and the steam passed through until #bjj cubic centimeters have been collected in the receiver4 ,the distillate is titrated with decinormal sodium hydroxid solution and the result expressed as acetic acid4 ,one cubic centimeter of decinormal sodium hydroxid solution #j4jjfj gram acetic acid4 ,the acidity due to volatile acids may be determined by ascertaining the total acidity as above described1 evaporating #ajj cubic centimeters to one-third of their volume1 restoring the original volume with water and again titrating4 ,the difference between the first and second titrations represents the volatile acidity4 ,a method of determining volatile acidity in wines1 without the application of heat1 has been proposed by de la ,source4#fda ,the sample1 five cubic centimeters1 freed of carbon dioxid by shaking1 is placed in a flat dish about eight centimeters in diameter4 ,in a separate portion of the sample1 the total acidity is determined in the presence of phenolphthalien by a set solution of barium hydroxid1 one cubic centimeter of which is equal to four milligrams of sulfuric acid4 ,the sample in the flat dish is placed in a desiccator1 which contains both sulfuric acid and solid potassium hydroxid1 and left for two days1 by which time it is practically dry4 ,the residue is dissolved in two cubic centimeters of warm water and the dish is kept in the desiccator for an additional two days4 ,by this time the volatile acids1 even acetic1 will have disappeared and the residual acidity is determined after solution in water4 ,the method is also applicable when wines have been treated with an alkali4 ,in this case two samples of five cubic centimeters each are acidified with two cubic centimeters of a solution of tartaric acid containing twenty-five grams per liter4 ,this treatment sets free the volatile acids1 and their quantity is determined as before4 #fbi4 ,titration with ,phenolphthalien4--,the total acidity is also easily determined by titration with a set alkali1 using phenolphthalien as indicator4 ,colored liquors must be treated with animal black before the analysis4 ,the sample is shaken to expel carbon dioxid and five cubic centimeters added to #ajj of water containing phenolphthalien4 ,the set alkali 7tenth normal soda7 is added until the red color is discharged4 ,even wines having a considerable degree of color may be titrated in this way4#fdb ,the acidity1 expressed as tartaric1 may be stated as due to sulfuric by dividing by #a4ec4 #fcj4 ,determination of ,tartaric ,acid4--,the determination of potassium bitartrate is necessary when an estimation of the free tartaric acid is desired4#fdc ,fifty cubic centimeters of wine are placed in a porcelain dish and evaporated to a sirupy consistence1 a little quartz sand being added to render subsequent extraction easier4 ,after cooling1 seventy cubic centimeters of ninety-six per cent alcohol are added with constant stirring4 ,after standing for twelve hours1 at as low a temperature as practicable1 the solution is filtered and the precipitate washed with alcohol until the filtrate is no longer acid4 ,the alcoholic filtrate is preserved for the estimation of the tartaric acid4 ,the filter and precipitate are returned to the porcelain dish and repeatedly treated with hot water1 each extraction being filtered into a flask or beaker until the washings are neutral4 ,the combined aqueous filtrates and washings are titrated with decinormal sodium hydroxid solution4 ,one cubic centimeter of decinormal sodium hydroxid solution #j4jahh gram potassium bitartrate4 ,the alcoholic filtrate is made up to a definite volume with water and divided into two equal portions4 ,one portion is exactly neutralized with decinormal sodium hydroxid solution1 the other portion added1 the alcohol evaporated1 the residue washed into a porcelain dish and treated as above4 ,one cubic centimeter decinormal sodium hydroxid solution #j4jjge gram tartaric acid4 ,as1 however1 only half of the free tartaric acid is determined by this method3 ,one cubic centimeter decinormal sodium hydroxid #j4jaej gram of tartaric acid4 #fca4 ,modified ,berthelot-,fleury ,method4--,ten cubic centimeters of wine are neutralized with potassium hydroxid solution and mixed in a graduated cylinder with forty cubic centimeters of the same sample4 ,to one-fifth of the volume1 corresponding to ten cubic centimeters of wine1 fifty cubic centimeters of a mixture of equal parts of alcohol and ether are added and allowed to stand twenty-four hours4 ,the precipitated potassium bitartrate is separated by filtration1 dissolved in water and titrated4 ,the excess of potassium bitartrate over the amount of that constituent present in the wine corresponds to the free tartaric acid4#fdd #fcb4 ,determination of ,tartaric1 ,malic and ,succinic ,acids4--,two hundred cubic centimeters of wine are evaporated to one-half1 cooled and lead subacetate solution added until the reaction is alkaline4#fde ,the precipitate is separated by filtration and washed with cold water until the filtrate shows only a slight reaction for lead4 ,the precipitate is washed from the filter into a beaker1 by means of hot water1 and treated hot with hydrogen sulfid until all the lead is converted into sulfid4 ,it is then filtered hot and the lead sulfid washed with hot water until the washings are no longer acid4 ,the filtrate and washings are evaporated to fifty cubic centimeters and accurately neutralized with potassium hydroxid4 ,an excess of a saturated solution of calcium acetate is added and the liquid allowed to stand from four to six hours with frequent stirring4 ,it is then filtered and the precipitate washed until the filtrate amounts to exactly #ajj cubic centimeters4 ,the precipitate of calcium tartrate is converted into calcium oxid by igniting in a platinum crucible4 ,after cooling1 from ten to fifteen cubic centimeters of normal hydrochloric acid are added1 the solution washed into a beaker and accurately titrated with normal potassium hydroxid solution4 ,every cubic centimeter of normal acid saturated by the calcium oxid is equivalent to #j4jgej gram tartaric acid4 ,to the amount so obtained1 #j4jbhf gram must be added1 representing the tartaric acid held in solution in the filtrate as calcium tartrate4 ,the sum represents the total tartaric acid in the wine4 ,the filtrate from the calcium tartrate is evaporated to about twenty-five cubic centimeters1 cooled and mixed with three times its volume of ninety-six per cent alcohol4 ,after standing several hours1 the precipitate is collected on a weighed filter1 dried at #ajj and weighed4 ,it represents the calcium salts of malic1 succinic and sulfuric acids and of the tartaric acid which remained in solution4 ,this precipitate is dissolved in a minimum quantity of hydrochloric acid1 filtered and the filter washed with hot water4 ,potassium carbonate solution is added to the hot filtrate1 and the precipitated calcium carbonate separated by filtration and washed4 ,the filtrate contains the potassium salts of the above named acids4 ,it is neutralized with acetic acid1 evaporated to a small volume and precipitated hot with barium chlorid4 ,the precipitate of barium succinate and sulfate is separated by filtration1 washed with hot water and treated on the filter with dilute hydrochloric acid4 ,the barium sulfate remaining is washed1 dried1 ignited and weighed4 ,in the filtrate1 which contains the barium succinate1 the barium is precipitated hot with sulfuric acid1 washed1 dried1 ignited and weighed4 ,two hundred and twenty-three parts of barium sulfate equal #aah parts of succinic acid4 ,the succinic and sulfuric acids1 as well as the tartaric acid remaining in solution1 which is equal to #j4jbhf gram1 are to be calculated as calcium salts and the result deducted from the total weight of the calcium precipitate4 ,the remainder is the calcium malate1 of which #agb parts equal #acd parts malic acid4 ,according to ,macagno1 succinic acid may be estimated in wines by the following process3#fdf ,one liter of the wine is digested with lead hydroxid1 evaporated on the water bath and the residue extracted with strong alcohol4 ,the residual salts of lead are boiled with a ten per cent solution of ammonium nitrate1 which dissolves the salts of succinic acid4 ,the solution is filtered1 the lead removed by hydrogen sulfid1 boiled1 neutralized with ammonia and treated with ferric chlorid as long as a precipitate is formed4 ,the ferric succinate is separated by filtration1 washed and ignited4 ,the succinic acid is calculated from the weight of ferric oxid obtained4 ,malic acid in wines and ciders is determined by the method of ,berthelot in the following manner3#fdg ,the sample is evaporated until reduced to a tenth of its volume4 ,to the residue an equal volume of ninety per cent alcohol is added and the mixture set aside for some time4 ,the tartaric acid and tartrates separate1 together with the greater part of the salts of lime which may be present4 ,the supernatant liquid is decanted and a small quantity of lime added to it until in slight excess of that required to neutralize the acidity4 ,calcium malate is separated mixed with lime4 ,the solid matters are separated by filtration1 dissolved in a ten per cent solution of nitric acid1 from which the lime bimalate will separate in a crystalline form4 ,the weight of calcium bimalate multiplied by #j4ei gives that of the malic acid4 #fcc4 ,polarizing ,bodies in ,fermented ,beverages4--,the study of the nature of the carbohydrates1 which constitute an important part of the solid matters dissolved in fermented beverages1 is of the greatest importance4 ,these bodies consist of grape sugars1 sucrose1 tartaric acid and the unfermented hydrolytic products derived from starch4 ,a natural grape sugar 7chiefly dextrose7 is found in wines4 ,sucrose is also a very important constituent of sweet wines4 ,the hydrolytic products of starch are found in beers1 either as a residue from the fermentation of malt or from the rice1 glucose1 hominy grits etc41 added in brewing4 ,the character and quantities of these residues can be determined by the methods already given in the parts of this volume relating to sugars and starches4 ,for convenience1 however1 and for special application to the investigation of fermented beverages a rsum of the methods adopted by the official chemists follows3#fdh #fcd4 ,determination of ,reducing ,sugars4--,the reducing sugars are estimated as dextrose1 and may be determined by any of the methods given for the estimation thereof 7#aac-adj74 #fce4 ,polarization4--,all results are to be stated as the polarization of the undiluted sample4 ,the triple field shadow saccharimeter is recommended1 and the results are expressed in the terms of the sugar scale of this instrument4 ,if any other instrument be used1 or if it be desirable to convert to angular rotation1 the following factors may be employed3 #a ,schmidt and ,haensch #j4cdfh angular rotation ,d4 #a angular rotation ,d #b4hhce ,schmidt and ,haensch4 #a ,schmidt and ,haensch #b4fjdh ,wild 7sugar scale74 #a ,wild 7sugar scale7 #j4chdj ,schmidt and ,haensch4 #a ,wild 7sugar scale7 #j4acca angular rotation ,d4 #a angular rotation ,d #j4geaa ,wild 7sugar scale74 #a ,laurent 7sugar scale7 #j4bafg angular rotation ,d4 #a angular rotation ,d #d4faed ,laurent 7sugar scale74 ,in the above table ,d represents the angular rotation produced with yellow monochromatic light4 7a7 ,in ,white ,wines or ,beers4--,sixty cubic centimeters of wine are decolorized with three cubic centimeters of lead subacetate solution and filtered4 ,thirty cubic centimeters of the filtrate are treated with one and five-tenths cubic centimeters of a saturated solution of sodium carbonate1 filtered and polarized4 ,this gives a solution of nearly ten to eleven1 which must be considered in the calculation1 and the polariscope reading must accordingly be increased one-tenth4 7b7 ,in ,red ,wines4--,sixty cubic centimeters of wine are decolorized with six cubic centimeters of lead subacetate solution and filtered4 ,to thirty cubic centimeters of the filtrate1 three cubic centimeters of a saturated solution of sodium carbonate are added1 filtered and the filtrate polarized4 ,the dilution in this case is nearly five to six1 and the polariscope reading must accordingly be increased one-fifth4 7c7 ,in ,sweet ,wines4 7#a7 ,before ,inversion4--,one hundred cubic centimeters are decolorized with two cubic centimeters of lead subacetate solution and filtered after the addition of eight cubic centimeters of water4 ,one-half cubic centimeter of a saturated solution of sodium carbonate and four and five-tenths cubic centimeters of water are added to fifty-five cubic centimeters of the filtrate1 the liquids mixed1 filtered and polarized4 ,the polariscope reading is multiplied by #a4b4 7#b7 ,after ,inversion4--,thirty-three cubic centimeters of the filtrate from the lead subacetate in 7#a7 are placed in a flask with three cubic centimeters of strong hydrochloric acid4 ,after mixing well1 the flask is placed in water and heated until a thermometer1 placed in the flask with the bulb as near the center of the liquid as possible1 marks #fh1 consuming about fifteen minutes in the heating4 ,it is then removed1 cooled quickly to room temperature1 filtered and polarized1 the temperature being noted4 ,the polariscope reading is multiplied by #a4b4 ,because of the action of lead subacetate on invert sugar 7#hg7 it is advisable to decolorize the samples with other reagents 7#hg-hi74 7#c7 ,after ,fermentation4--,fifty cubic centimeters of wine1 which have been dealcoholized by evaporation and made up to the original volume with water1 are mixed1 in a small flask1 with well washed beer yeast and kept at #cj until fermentation has ceased1 which requires from two to three days4 ,the liquid is washed into a #ajj cubic centimeter flask1 a few drops of a solution of acid mercuric nitrate and then lead subacetate solution1 followed by sodium carbonate1 added4 ,the flask is filled to the mark with water1 shaken1 the solution filtered and polarized and the reading multiplied by two4 #fcf4 ,application of ,analytical ,methods4--7#a7 ,there is no rotation4--,this may be due to the absence of any rotatory body1 to the simultaneous presence of the dextrorotatory nonfermentable constituents of commercial dextrose and levorotatory sugar1 or to the simultaneous presence of dextrorotatory cane sugar and levorotatory invert sugar4 7a7 ,the ,wine is ,inverted4--,a levorotation shows that the sample contains cane sugar4 7b7 ,the ,wine is ,fermented4--,a dextrorotation shows that both levorotatory sugar and the unfermentable constituents of commercial dextrose are present4 ,if no change take place in either 7a7 or 7b7 in the rotation1 it proves the absence of unfermented cane sugar1 the unfermentable constituents of commercial dextrose and of levorotatory sugar4 7#b7 ,there is right rotation4--,this may be caused by unfermented cane sugar1 the unfermentable constituents of commercial dextrose or both4 7a7 ,the sugar is inverted3 7a7 ,it rotates to the left after inversion4--,unfermented cane sugar is present4 7a7 ,it rotates more than #b4c to the right4--,the unfermentable constituents of commercial dextrose are present4 7a7 ,it rotates less than #b4c and more than #j4i to the right4--,it is in this case treated as follows3 ,two hundred and ten cubic centimeters of the sample are evaporated to a thin sirup with a few drops of a twenty per cent solution of potassium acetate4 ,to the residue #bjj cubic centimeters of ninety per cent alcohol are added with constant stirring4 ,the alcoholic solution is filtered into a flask and the alcohol removed by distillation until about five cubic centimeters remain4 ,the residue is mixed with washed bone-black1 filtered into a graduated cylinder and washed until the filtrate amounts to thirty cubic centimeters4 ,when the filtrate shows a dextrorotation of more than #a4e1 it indicates the presence of unfermentable constituents of commercial dextrose4 7#c7 ,there is left rotation4--,the sample contains unfermented levorotatory sugar1 derived either from the must or mash or from the inversion of added cane sugar4 ,it may1 however1 also contain unfermented cane sugar and the unfermentable constituents of commercial dextrose4 7a7 ,the wine sugars are fermented according to directions in #bfb4 7a7 ,it polarizes #c after fermentation4--,it contains only levorotatory sugar4 7a7 ,it rotates to the right4-- ,it contains both levorotatory sugar and the unfermentable constituents of commercial dextrose4 7b7 ,the sucrose is inverted according to 7c71 in 7#b74 7b7 ,it is more strongly levorotatory after inversion4 ,in contains both levorotatory sugar and unfermented cane sugar4 #fcg4 ,estimation of ,sucrose1 ,dextrose1 ,invert ,sugar1 ,maltose and ,dextrin4--,the total and relative quantities of these carbohydrates are determined by the processes already described 7#bcg-bfb74 #fch4 ,determination of ,glycerol4--7a7 ,in ,dry ,wines and ,beers4--,one hundred cubic centimeters of wine are evaporated in a porcelain dish to about ten cubic centimeters1 a little quartz sand and milk of lime added and the evaporation carried almost to dryness4 ,the residue is mixed with fifty cubic centimeters of ninety per cent alcohol1 using a glass pestle or spatula to break up any solid particles1 heated to boiling on the water bath1 allowed to settle and the liquid filtered into a small flask4 ,the residue is repeatedly extracted in a similar manner1 with small portions of boiling alcohol1 until the filtrate in the flask amounts to about #aej cubic centimeters4 ,a little quartz sand is added1 the flask connected with a condenser and the alcohol slowly distilled until about ten cubic centimeters remain4 ,the evaporation is continued on the water bath until the residue becomes sirupy4 ,it is cooled and dissolved in ten cubic centimeters of absolute alcohol4 ,the solution may be facilitated by gentle heating on the steam bath4 ,fifteen cubic centimeters of anhydrous ether are added1 the flask stoppered and allowed to stand until the precipitate has collected on the sides and bottom of the flask4 ,the clear liquid is decanted into a tared weighing bottle1 the precipitate repeatedly washed with a few cubic centimeters of a mixture of one part of absolute alcohol and one and five-tenths parts anhydrous ether and the washings added to the solution4 ,the ether-alcohol is evaporated on the steam bath1 the residue dried one hour in a water oven1 weighed1 the amount of ash determined and its weight deducted from that of the weighed residue to get the quantity of glycerol4 7b7 ,in ,sweet ,wines4--,one hundred cubic centimeters of wine are evaporated on the steam bath to a sirupy consistence1 a little quartz sand being added to render subsequent extraction easier4 ,the residue is repeatedly treated with absolute alcohol until the united extracts amount to from #ajj to #aej cubic centimeters4 ,the solution is collected in a flask and for every part of alcohol one and five-tenths parts of ether are added1 the liquid well shaken and allowed to stand until it becomes clear4 ,the supernatant liquor is decanted into a beaker and the precipitate washed with a few cubic centimeters of a mixture of one part alcohol and one and five-tenths parts ether4 ,the united liquids are distilled1 the evaporation being finished on the water bath1 the residue is dissolved in water1 transferred to a porcelain dish and treated as under 7a74 #fci4 ,determination of ,coloring ,matters in ,wines4--,the methods of detecting the more commonly occurring coloring matters in wines as practiced by the official chemists are given below4 7a7 ,cazeneuve ,reaction4--,add two-tenths gram of precipitated mercuric oxid to ten cubic centimeters of wine1 shake for one minute and filter4 ,pure wines give filtrates which are colorless or light yellow1 while the presence of a more or less red coloration indicates that an anilin color has been added to the wine4 7b7 ,method of ,sostegni and ,carpentieri4--,evaporate the alcohol from #bjj cubic centimeters of wine4 ,add from two to four cubic centimeters of a ten per cent solution of hyrochloric acid1 immerse therein some threads of fat-free wool and boil for five minutes4 ,remove the threads1 wash them with cold water acidified with hydrochloric1 then with hot water acidified with hydrochloric1 then with pure water and dissolve the color in a boiling mixture of fifty cubic centimeters of water and two cubic centimeters of concentrated ammonia4 ,replace the threads by new ones1 acidify with hydrochloric and boil again for five minutes4 ,in the presence of anilin colors to the amount of two milligrams per liter1 the threads are dyed as follows3 ,safranin light rose-red4 ,vinolin rose-red to violet4 ,bordeaux-red rose-red to violet4 ,ponceau-red rose-red4 ,tropolin oo straw yellow4 ,tropolin ooo light orange4 7c7 ,detection of ,fuchsin and ,orseille4--,to twenty cubic centimeters of wine add ten cubic centimeters of lead acetate solution1 heat slightly and mix by shaking4 ,filter into a test-tube1 add two cubic centimeters of amyl alcohol and shake4 ,if the amyl alcohol be colored red1 separate it and divide it into two portions4 ,to one add hydrochloric acid1 to the other ammonia4 ,when the color is due to fuchsin1 the amyl alcohol will in both cases be decolorized2 when due to orseille1 the ammonia will change the color of the amyl alcohol to purple-violet4 #fdj4 ,determination of ,ash4--,the residue from the direct extract determination is incinerated at as low a heat as possible4 ,repeated moistening1 drying and heating to low redness is advisable to get rid of all organic substances4 ,when a quantitive analysis of the ash is desired1 large quantities of the sample are evaporated to dryness and the residue incinerated with the usual precautions4 #fda4 ,determination ,of ,potash4--7a7 ,kayser's ,method4--,dissolve seven-tenths gram pure sodium hydroxid and two grams of tartaric acid in #ajj cubic centimeters of wine1 add #aej cubic centimeters of ninety-two to ninety-four per cent alcohol and allow the liquid to stand twenty-four hours4 ,the precipitated potassium bitartrate is collected on a small filter and washed with fifty per cent alcohol until the filtrate amounts to #bfj cubic centimeters4 ,the precipitate and filter are transferred to the beaker in which the precipitation was made1 the precipitate dissolved in hot water1 the volume made up to #bjj cubic centimeters and fifty cubic centimeters thereof titrated with decinormal sodium hydroxid solution1 adding #j4jjd gram to the final result1 representing the potash which remains in solution as bitartrate4 7b7 ,platinum ,chlorid ,method4--,evaporate #ajj cubic centimeters of the wine to dryness1 incinerate the residue and determine the potash as in ash analysis4#fdi #fdb4 ,determination of ,sulfurous ,acid4--,one hundred cubic centimeters of wine are distilled in a current of carbon dioxid1 after the addition of phosphoric acid1 until about fifty cubic centimeters have passed over4 ,the distillate is collected in accurately set iodin solution4 ,when the distillation is finished1 the excess of iodin is determined with set sodium thiosulfate solution and the sulfurous acid calculated from the iodin used4 #fdc4 ,detection of ,salicylic ,acid4--7a7 ,spica's ,method4--,acidify #ajj cubic centimeters of the liquor with sulfuric and extract with sulfuric ether4 ,evaporate the extract to dryness1 warm the residue carefully with one drop of concentrated nitric acid and add two or three drops of ammonia4 ,the presence of salicylic acid in the liquor is indicated by the formation of a yellow color due to ammonium picrate and may be confirmed by dyeing therein a thread of fat-free wool4 7b7 ,bigelow's ,method4--,place #ajj cubic centimeters of the wine in a separatory funnel1 add five cubic centimeters of sulfuric acid 7#a-c7 and extract with a sufficient quantity of a mixture of eight or nine parts of ether to one part of petroleum ether4 ,throw away the aqueous part of the extract1 wash the ether once with water1 then shake thoroughly with about fifty cubic centimeters of water1 to which from six to eight drops of a one-half per cent solution of ferric chlorid have been added4 ,discard the aqueous solution1 which contains the greater part of the tannin in combination with iron1 wash again with water1 transfer the ethereal solution to a porcelain dish and allow to evaporate spontaneously4 ,heat the dish on the steam bath1 take up the residue with one or two cubic centimeters of water1 filter into a test-tube and add one to two drops of one-half per cent solution of ferric chlorid4 ,the presence of salicylic acid is indicated by the appearance of a violet-red coloration4 ,in the case of red wines1 a second extraction of the residue with ether mixture is sometimes necessary4 ,this method cannot be used in the examination of beers and ales4 7c7 ,girard's ,method4--,extract a portion of the acidified liquor with ether as in the preceding methods1 evaporate the extract to dryness and exhaust the residue with petroleum ether4 ,the residue from the petroleum ether extract is dissolved in water and treated with a few drops of a very dilute solution of ferric chlorid4 ,the presence of salicylic acid is indicated by the appearance of a violet-red coloration4 #fdd4 ,detection of ,gum and ,dextrin4--,four cubic centimeters of the sample are mixed with ten cubic centimeters of ninety-six per cent alcohol4 ,when gum arabic or dextrin is present1 a lumpy1 thick and stringy precipitate is produced1 whereas pure wine becomes at first opalescent and then gives a flocculent precipitate4 #fde4 ,determination of ,nitrogen4--,the best method of determining nitrogen in fermented beverages is the common one of moist combustion with sulfuric acid4 ,the sample is placed in the kjeldahl digestion flask1 which is attached to the vacuum service and placed in a steam bath until its contents are dry or nearly so4 ,the process is then conducted in harmony with the well known methods4 ,where large quantities of the sample are to be employed1 as in drinks containing but little nitrogen1 the preliminary evaporation may be accomplished in an open dish1 the contents of which are transferred to the digestion flask before any solid matter is deposited4 ,the same procedure may be followed when the sample foams too much on heating4 #fdf4 ,substitutes for ,hops4--,it is often claimed that cheap and deleterious bitters are used in brewing in order to save hops4 ,while it is doubtless true that foreign bitters are sometimes employed1 the experience of this laboratory goes to show that such an adulteration is not very prevalent in this country4#fej ,possibly strychnin1 picrotoxin1 quassin1 gentian and other bitter principles have sometimes been found in beer1 but their use is no longer common4 ,it is difficult to decide in every case whether or not foreign bitters have been added4 ,a common process is to treat the sample with lead acetate1 filter1 remove the lead from the filtrate and detect any remaining bitters by the taste4 ,all the hop bitters are removed by the above process4 ,any remaining bitter taste is due to other substances4 ,for the methods of detecting the special bitter principles in hops and other substances1 the work of ,dragendorff may be consulted4#fea #fdg4 ,bouquet of ,fermented and ,distilled ,liquors4--,the bouquet of fermented and distilled liquors is due to the presence of volatile matters which may have three different origins4 ,in the first place the materials from which these beverages are made contain essential oils and other odoriferous principles4#feb ,in the grape1 for instance1 the essential oils are found particularly in the skins4 ,these essential principles may be secured by distilling the skins of grapes in a current of steam4 ,this method of separation1 however1 cannot be regarded as strictly quantitive4 ,in the second place1 the yeasts which produce the alcoholic fermentation are also capable of producing odoriferous products4 ,these minute vegetations1 resembling in their biological relations the mushrooms1 grow in the soil and reach their maturity at about the time of the harvest of the grapes4 ,their spores are transmitted through the air1 reach the expressed grape juice and produce the vinous fermentation4 ,the particular odor due to any given yeast persists through many generations of culture showing that the body which produces the odor is the direct result of the vegetable activity of the yeast4 ,a beer yeast1 after many generations of culture1 will still give a product which smells like beer1 and in like manner a wine yeast will produce one which has the odor of wine4 ,the quantity of odorant matter produced by this vegetable action is so minute as to escape detection in a quantitive or qualitive way by chemical means4 ,these subtle perfumes arise moreover not only from the breaking up of the sugar molecule1 but are also the direct results of molecular synthesis accomplished under the influence of the yeast itself4 ,in the third place1 the fermented and distilled liquors contain odoriferous principles due to the chemical reactions which take place by the breaking up of the sugar and other molecules during the process of fermentation4 ,the alcohols and acids produced have distinct odors by which they are often recognized4 ,this is particularly true of ethylic1 propylic1 butylic1 amylic and oenanthylic alcohols and acetic acid4 ,these alcohols themselves also undergo oxidation1 passing first into the state of aldehyds which1 together with ethers1 produce the peculiar aroma which is found in various fruits4 ,the etherification noted above is of course preceded by the formation of acids corresponding to the various aldehyds present4 ,the formation of these ethers takes place very slowly during aging1 and it therefore requires three or four years for the proper ripening of wines or distilled liquors4 ,by means of artificial heat1 electricity and aeration1 the oxidizing processes above noted may be hastened1 but it is doubtful whether the products arising from this artificial treatment are as perfect as those which are formed in the natural processes4 ,,authorities ,,cited ,,in ,,part ,,seventh4 #ece ,bulletin #df1 ,chemical ,division ,u4 ,s4 ,department of ,agriculture1 pp4 #bd-be4 #ecf ,bulletin #db1 ,arkansas ,agricultural ,experiment ,station1 pp4 #ha et seq4 #ecg ,balland2 ,recherches sur les ,bls1 les ,farines et le ,pain1 p4 #bbi4 #ech ,jago2 ,flour and ,bread1 p4 #deg4 #eci ,jago2 op4 cit4 supra1 p4 #dfe4 #edj ,richardson2 ,journal of the ,chemical ,society1 ,transactions1 #ahhe1 pp4 #hd et seq4 #eda ,auct4 et op4 cit4 supra1 pp4 #hj et seq4 #edb ,bulletin #bh1 ,office of ,experiment ,stations1 ,u4 ,s4 ,department of ,agriculture1 pp4 #i1 #aj4 #edc ,bulletin #bi1 ,office of ,experiment ,stations ,u4 ,s4 ,department of ,agriculture1 p4 #h4 #edd ,op4 et4 loc4 cit4 supra4 #ede ,experiment ,station ,record1 ,vol4 #f1 pp4 #eij et seq4 #edf ,annual ,report1 ,u4 ,s4 ,department of ,agriculture1 #ahhd1 p4 #cfe4 #edg ,forschungs-,berichte ber ,lebensmittel1 ,band #c1 ,s4 #adb4 #edh ,zeitschrift fr angewandte ,chemie1 #ahie1 ,s4 #fbj4 #edi ,op4 et loc4 cit4 supra4 #eej ,les ,ferments ,solubles2 ,diastases--,enzymes4 #eea ,wiley2 ,medical ,news1 ,july1 #ahhh4 #eeb ,virchow's ,archiv41 ,band #abc1 ,s4 #bcj3 ,journal of the ,chemical ,society1 ,abstracts1 #ahib1 p4 #gee4 #eec ,ladenberg2 ,handwrterbuch der ,chemie1 ,band #d1 ,s4 #abb4 #eed ,chemisches ,centralblatt1 #ahib1 ,band #b1 ,s4 #egi4 #eee ,op4 cit4 supra1 #ahij1 ,band #b1 ,s4 #fbh4 #eef ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #dd1 ,s4 #ahh2 ,experiment ,station ,record1 ,vol4 #f1 p4 #ab4 #eeg ,experiment ,station ,record1 ,vol4 #f1 pp4 #e et seq4 7,read ,jordan instead of ,gordon47 #eeh ,journal of the ,american ,chemical ,society1 ,vol4 #af1 pp4 #eij et seq4 #eei ,from photograph made in this laboratory by ,bigelow4 #efj ,journal of the ,society of ,chemical ,industry1 ,vol4 #aj1 p4 #aah4 #efa ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #cf1 ,s4 #cba3 ,bulletin #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #ajbh4 #efb ,wilson2 ,vid4 op4 et loc4 cit4 #bf4 #efc ,u4 ,s4 ,dispensatory1 p4 #ajhh4 #efd ,landwirtschaftliche ,jahrbcher1 #ahij1 ,band #ai1 ,s4 #adi4 #efe ,bulletin #ac1 ,chemical ,division1 ,u4,s4 ,department of ,agriculture1 p4 #ajbh4 #eff ,zeitschrift fr analytische ,chemie1 ,band #ce1 ,s4 #dih4 #efg ,annual ,report of the ,maine ,agricultural ,experiment ,station1 #ahia1 p4 #be3 ,gay2 ,annales ,agronomiques1 #ahhe1 p4 #ade1 et #ahif1 pp4 #ade et seq4 #efh ,annales ,agronomiques1 ,tome #ba1 pp4 #adi1 #aej4 #efi ,vid4 op4 et loc4 cit4 primo sub #cc4 #egj ,twelfth ,annual ,report of the ,massachusetts ,agricultural ,experiment ,station1 #ahid1 p4 #age4 #ega ,see also paragraph #ehf this volume4 #egb ,manuscript prepared for publication as a part of ,bulletin #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture4 #egc ,vid4 this volume1 paragraph #bhj4 #egd ,vid4 op4 cit4 #ca1 p4 #ajbj4 #ege ,bulletin #de1 ,chemical ,division1 ,u4,s4 ,department of ,agriculture1 p4 #ab4 #egf ,berthelot2 ,essai de ,chimie ,mcanique3 ,thomsen2 ,thermo ,chemische ,untersuchungen3 ,ostwald2 ,algemeine ,chemie3 ,muir2 ,elements of ,thermal ,chemistry4 #egg ,bulletin #ba1 ,office of ,experiment ,stations1 ,u4 ,s4 ,department of ,agriculture1 pp4 #aac et seq43 ,seventh ,annual ,report ,connecticut 7,storr's7 ,agricultural ,experiment ,station1 pp4 #acc et seq4 #egh ,vid4 op4 et loc4 cit4 #dc4 #egi ,from personal inspection by author in ,williams' laboratory1 #afa ,tremont ,st41 ,boston1 ,mass4 #ehj ,journal fr praktische ,chemie1 ,band #adg ,neue ,folge ,band #ci1 ,ss4 #eag et seq4 #eha ,berthelot2 ,annales de ,chemie et de ,physique1 #f;e ,srie1 ,tome #aj1 p4 #dci4 #ehb ,vid4 op4 cit4 #df1 ,ss4 #ebb-ebc4 ,the data in paragraph #eff are taken from ,stohmann1 ,zeitschrift fr ,biologie1 ,band #ca1 ,s4 #cfd and ,experiment ,station ,record1 ,vol4 #f1 p4 #eij4 #ehc ,journal of the ,american ,chemical ,society1 ,vol4 #ah1 p4 #agd4 #ehd ,bulletins #ic1 #ig1 #aja and #ajb1 ,california ,agricultural ,experiment ,station4 #ehe ,annual ,report1 ,u4 ,s4 ,department of ,agriculture1 #ahhf1 p4 #ced4 #ehf ,this work1 ,vol4 #b1 p4 #cah4 #ehg ,vid4 ,california ,bulletins cited under #ej3 ,wolff2 ,aschen ,analyse1 ,s4 #abf4 #ehh ,bulletin #ajj1 ,cornell ,agricultural ,experiment ,station3 ,bulletin #dh1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture4 #ehi ,vid4 op4 cit4 #ea1 p4 #cec4 #eij ,vid4 op4 cit4 ultimo sub #ed4 #eia ,bulletin ,no4 #db1 ,arkansas ,agricultural ,experiment ,station1 p4 #gh4 #eib ,annual ,report1 ,u4 ,s4 ,department of ,agriculture1 #ahhd1 p4 #cdg4 #eic ,spencer2 ,bulletin #ac1 ,u4 ,s4 ,department of ,agriculture1 pp4 #hge et seq4 #eid ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #d1 p4 #cij2 ,bulletin #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #hhi4 #eie ,pharmaceutical ,journal1 ,vol4 #eb1 p4 #bac4 #eif ,commercial ,organic ,analysis1 ,vol4 #c1 part #b1 p4 #dhd4 #eig ,journal de ,pharmacie et de ,chimie1 #f ,srie1 ,tome #c1 p4 #ebi4 #eih ,journal of the ,american ,chemical ,society1 ,vol4 #ah1 p4 #cch4 #eii ,manuscript communication to author4 #fjj ,vid4 op4 cit4 #fc1 p4 #ecc4 #fja ,american ,chemical ,journal1 ,vol4 #ad1 p4 #dgc4 #fjb ,op4 et loc4 cit4 supra4 #fjc ,lindsey2 ,report made to ,thirteenth ,annual ,convention of the ,association of ,official ,agricultural ,chemists1 ,nov4 #fth1 #ahif3 ,tollens2 ,handbuch der ,kohlenhydrate1 ,band #b1 ,s4 #eb4 #fjd ,zeitschrift fr angewandte ,chemie1 #ahif1 p4 #aie1 #fje ,comptes rendus hebdomadaires de ,seances de l',academie des ,sciences1 ,tome #abb1 p4 #hda4 #fjf ,the ,tannins1 two volumes4 #fjg ,dragendorff2 ,plant ,analysis4 #fjh ,the ,tannins1 ,vol4 #a1 p4 #cc4 #fji ,bulletin #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #ijh4 #faj ,vid4 op4 cit4 #gd1 p4 #ch4 #faa ,bulletin #df1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #gg as revised at #acth annual meeting of the ,association of ,official ,agricultural ,chemists4 #fab ,vid4 op4 cit4 #ge1 p4 #hij3 ,zeitschrift fr analytische ,chemie1 ,band #be1 ,s4 #aba3 ,journal of the ,society of ,chemical ,industry1 ,vol4 #c1 p4 #hb3 ,trimble2 ,the ,tannins1 ,vol4 #a1 p4 #dd4 #fac ,vid4 op4 cit4 #gd1 p4 #dh4 #fad ,mc,elroy2 ,analyses made in this laboratory4 #fae ,annual ,report ,connecticut ,agricultural ,experiment ,station 7,new ,haven7 #ahib1 p4 #cj4 #faf ,kissling2 ,tabakkunde1 ,s4 #dj4 #fag ,vid4 op4 cit4 supra1 ,s4 #eh4 #fah ,vid4 op4 cit4 #ha1 p4 #bi4 #fai ,this work1 ,vol #a1 pp4 #ejj et seq4 #fbj ,this work1 ,vol4 #a1 p4 #dbj4 #fba ,vid4 op4 cit4 #hb1 ,s4 #fb4 #fbb ,vid4 op4 cit4 supra1 ,s4 #fd4 #fbc ,dragendorff2 ,plant ,analysis1 p4 #fe4 #fbd ,sugar1 #ahif1 ,march #aeth1 p4 #aa4 #fbe ,vid4 op4 cit4 #hb1 ,s4 #fe4 #fbf ,der ,tabak1 ,s4 #add4 #fbg ,vid4 op4 cit4 #hb1 ,s4 #fe3 ,zeitschrift fr analytische ,chemie1 ,band #ba1 ,s4 #gf3 ,band #bb1 ,s4 #aii3 ,band #cb1 ,s4 #bgg3 ,band #cd1 ,ss4 #dac-gca4 #fbh ,zeitschrift fr physiologische ,chemie ,band #ac1 ,s4 #dde3 ,band #ad1 ,s4 #ahb4 #fbi ,zeitschrift fr analytische ,chemie1 ,band #cd1 ,s4 #dac1 ,band #ce1 ,ss4 #cji1 #gca4 #fcj ,annual ,report ,connecticut ,agricultural ,experiment ,station 7,new ,haven71 #ahib1 p4 #ag4 #fca ,buell2 ,the ,cider-makers' ,manual3 ,southby2 ,systematic ,text-,book of ,practical ,brewing3 ,moritz and ,morris2 ,text-,book of the ,science of ,brewing4 #fcb ,gautier2 ,sophistication et ,analyse des ,vins1 p4 #di4 #fcc ,auct4 et4 op4 cit4 supra1 p4 #dd4 #fcd ,bulletin #df1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #fc4 #fce ,manuscript not yet published4 #fcf ,vid4 op4 cit4 #ajj1 pp4 #ie et seq4 #fcg ,wiley2 ,journal of the ,american ,chemical ,society1 ,vol4 #ah1 p4 #ajfc4 #fch ,vid4 op4 cit4 #ajj1 p4 #gj4 #fci ,vid4 op4 cit4 #ih1 p4 #fe4 #fdj ,vid4 op4 cit4 #ih1 p4 #fg4 #fda ,the ,analyst1 ,vol4 #ba1 p4 #aeh4 #fdb ,vid4 op4 cit4 #ih1 p4 #ih4 #fdc ,vid4 op4 cit4 #ajj1 p4 #gd4 #fdd ,vid4 op4 cit4 #ajj1 p4 #ge4 #fde ,vid4 op4 cit4 #ajj1 p4 #ge4 #fdf ,bulletin de la ,socit ,chimique de ,paris1 ,srie #b1 ,tome #bd1 p4 #bhh2 ,berichte der deutschen chemischen ,gesellschaft1 ,band #h1 ,s4 #beg4 #fdg ,vid4 op4 cit4 #ih1 p4 #abj4 #fdh ,bulletin #df1 ,chemical ,division ,u4 ,s4 ,department of ,agriculture1 pp4 #gb1 et4 seq4 #fdi ,this work1 ,vol4 #b1 pp4 #bfg and #cbf4 #fej ,bulletin #ac1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #bif4 #fea ,plant ,analysis1 pp4 #ch1 et seq4 #feb ,repertoire de ,pharmacie1 ,srie #c;e1 ,tome #g1 p4 #dcf4 ,,index4 ,page4 ,a ,abbe1 refractometer1 #cbi ,acetic acid1 estimation in tobacco1 #fjb ,acetyl value1 #chd1 #che ,acidity1 estimation in fermented beverages1 #bg of milk1 determination1 #dgc ,acids1 determination in fruits and vegetables1 #egi ,agricultural products1 classification of miscellaneous1 #eda description1 #a ,air-bath1 drying1 #af ,albumin1 definition1 #daj gyrodynals of hydrates1 #bgf precipitants in milk1 #bgf qualitive tests1 #dbj separation in milk1 #eji ,albuminates1 definition and properties1 #daa estimation in cheese1 #eca qualitive tests1 #dba ,albuminoids1 #dac definition1 #daj ,albumins1 action1 on polarized light1 #dbb gyrodynats1 #dbb properties1 #daj separation1 #dci ,albumose peptone1 #dfa ,albumoses1 estimation1 in cheese1 #eca separation1 from peptones1 #dee ,alcohol1 calculating1 in fermented beverages1 #faf digestion1 #bde estimation1 by vapor temperature1 #fbb in ensilage1 #edf fermented beverages1 #fab koumiss1 #ecd sugar analysis1 #ahf reagent for precipitating dextrin1 #bib table showing percentage1 #fag-fba ,alcoholic digestion1 sugar beets1 #bdh-bej ,alcoholometer1 #fab ,aliphalytic ferments1 #eef ,alkali1 action on reducing sugars1 #aca1 #acb ,alkaline copper solutions1 comparison1 #abg-abi ,alkaloidal nitrogen1 estimation1 #dcb qualitive tests1 #dbb1 #dbc ,alkaloids1 occurrence1 #dag ,allantoin1 #dbh ,allein and ,gaud1 modification of ,pavy's process1 #ade ,allen1 modification of ,pavy's process1 #add potassium cyanid process1 #adf ,allihn1 gravimetric dextrose method1 #aee-aeh ,alum1 occurrence1 in bread1 #edd reagent for casein1 #ece ,alumina cream1 clarification1 #ajj ,aluminum dishes1 drying1 #cc ,amagat-,jean1 refractometer1 #ccd-cch ,amid nitrogen1 estimation1 #dbd in cereals1 #edc tobacco1 #fjg occurrence1 #dag qualitive test1 #dah separation1 in cheese1 #ecj ,ammonia1 estimation1 in tobacco1 #fje ,ammoniacal copper solution1 #adc nitrogen1 estimation1 #dbc1 #dbd in cheese1 #eca qualitive test1 #dai ,ammonium sulfate1 reagent for milk proteids1 #ejg precipitating proteids1 #dcc ,amyl alcohol1 use1 in milk fat analysis1 #eja ,amyliferous bodies1 desiccation1 #bii ,amyloid bodies in milk1 #eab ,amylolytic ferments1 #eef ,anatto1 #ebb ,animal products1 sampling1 #ddh substances1 preparation1 #d1 #e ,anoptose1 #bcd ,antipeptones1 #dab ,aqueous diffusion1 sugar beet analysis1 #bea1 #beb ,araban1 occurrence1 #ehf ,arabinose1 molecular weight1 #agg ,arachidic acid1 separation1 #cih1 #cii ,areometric method1 application in milk fat analysis1 #did1 #die ,areometry1 #gj ,artificial digestion1 #eee manipulation1 #efa smoker1 #fji ,ash1 composition1 in milk1 #dff1 #dfg of fruit1 #ehj estimation1 #cf in butter1 #eaf cereals1 #edb fermented beverages1 #fcg koumiss1 #ecf meats1 #eej milk1 #dhb proteids1 #ddd ,german method1 #ci ,asparagin1 #dag estimation1 #dbf1 #dbg preparation1 #dbf ,aspartic acid1 #dab ,atwater and ,woods1 calorimeter1 #efi methods of meat analysis1 #edi preparation of fish1 #ab ,auric chlorid1 color test with fats and oils1 #cef ,authorities cited in ,part ,fifth1 #dfb1 #dfc ,first1 #ef1 #eg ,fourth1 #djf-dji ,second1 #bbb ,seventh1 #fda-fdd ,sixth1 #ecf-edj ,third1 #cjf-cjh ,b ,babcock1 formula1 for calculating total solids1 #dgi1 #dhj method of counting fat globules1 #dhc1 #dhd milk fat analysis1 #dii1 #ejj ,bacteria1 reactions1 on sugar1 #aif ,bagasse1 analysis1 #bci1 #bdj ,barfoed1 reagent1 for removing dextrose1 #bia1 #bib ,barium saccharate1 #ahg ,barley starch1 #bba ,basic lead acetate1 clarification1 #aja ,baum and brix degrees1 comparison1 #gc ,bean starch1 #bbj ,bechi's test for cottonseed oil1 #djj1 #dja ,beet rasp1 #aj1 #bea ,beimling1 method of milk fat analysis1 #ejb ,betain1 #dag separation from cholin1 #dbi ,bigelow and ,mc,elroy1 estimation of sugar in evaporated milks1 #bif-bih method of dialysis1 #ddg table for correcting hydrostatic plummet1 #fae ,biliverdin1 occurrence in milk1 #dfd ,birotation1 #aah mathematical theory1 #agg1 #agh ,biuret reaction1 #dai ,block1 feculometer1 #cjj ,bone-black1 decolorization1 #ajd ,bordeaux-red1 determination1 in wines1 #fcg ,bouquet of fermented and distilled liquors1 #fdj1 #fda ,bread1 acidity1 #edd amount of water1 #edd baking1 temperature1 #edc chemical changes in baking1 #ede color1 #edd methods of analysis1 #edc-ede nitrogenous compounds1 #edd soluble extract1 #edc ,brix and baum degrees1 comparison1 #gc ,bromin addition number1 #cga-cgc ,brull1 color test for fats and oils1 #cee ,butter1 adulterants1 #eba appearance of melted1 #eac with polarized light1 #ead calorimetric distinction1 from oleomargarin1 #egf colors1 #ebb detection1 #ebc fat analysis1 classification of methods1 #dhd estimation1 #dhb-ejd methods of analysis1 #eab-ebc microscopic examination1 #eac molecular weight1 #ebj refractive index1 #ead relative proportion of ingredients1 #eag substitutes1 molecular weight1 #ebj1 #eba ,butyrin1 #caj ,butyrorefractometer1 #cci-cda range of application1 #cdb ,c ,caffein1 estimation1 #ehc ,caffetannic acid1 #eij ,calcium saccharates1 #ahh ,caldwell1 hydrogen drying oven1 #bf1 #bg ,calories1 computation1 #egd-egh definition1 #egf ,calorimeter1 description1 #efi formulas for calculation1 #egb hydrothermal value1 #egc manipulation1 #ega ,calorimetric equivalents1 #egf ,calorimetry1 #efh-egf ,canada balsam1 mounting starches1 #bai ,cane cutting machines1 #bcf1 #bcg pulp1 determination of sugar1 #bch drying and extraction1 #bch sugar1 gyrodynat1 #aag1 #aah ,carbohydrates1 #eh estimation in cereals1 #edc kind1 #eh milk1 #eaa molecular weights1 #age nomenclature1 #ei occurrence1 #eh in coffee1 #ehe of rare1 #cjf separation1 #bgi in fruits and vegetables1 #egg ,carbon1 estimation in proteids1 #ddd dioxid1 determination1 in sugar analysis1 #ahf estimation1 in koumiss1 #ecb reagent for casein1 #eji tetrachlorid1 reagent in iodin addition1 #cfh ,carnin1 #daf composition1 #dea ,carr1 vacuum drying oven1 #bb1 #bc ,casein1 estimation1 in butter1 #eaf cheese1 #eca with mercurial salts1 #ece factors for calculating1 #ejh method of estimating1 #ejh precipitants in milk1 #bgf precipitation1 by alum1 #ece preparation1 #eji separation1 by filtering through porous porcelain1 #ecd from albumin1 #ejg solution1 in acid1 #dhi theory of precipitation1 #ejh ,caseinogen1 #ejd ,cassava starch1 #bbb ,cattle foods1 #ede ,cellulose1 constitution1 #cjc qualitive reactions1 #cjf separation1 #cjd solubility1 #cje ,cereals1 general principles of analysis1 #edb ,chalmot and ,tollens1 method of estimating pentosans1 #ahb ,chandler 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,electric drying oven1 #ai ,ensilage1 alcohol1 #edf changes1 due to fermentation1 #edf comparative value1 #edg organic acids1 #edf ,ether extract1 estimation1 in cereals1 #edb solvent1 #da ,evaporated fruits1 #ehj milk1 estimation of sugar1 #bif ,ewell1 method of estimating coffee carbohydrates1 #ehe permanganate method1 #acf ,excreta1 collection1 #efb1 #efc ,extract1 composition1 in fermented beverages1 #fbd estimation1 by indirect method1 #fbe in fermented beverages1 #fbd vacuum1 #fbf ,extraction apparatus1 #dc-ea by digestion1 #db percolation1 #dc compact apparatus1 #dh-ea methods1 #da1 #db with alcohol1 #bde ,f ,fat acids1 determinations of nature1 #cif formulas for calculating yield1 #cib1 #cic temperature of crystallization1 #cbg crystals1 appearance1 with polarized light1 #cdg microscopic appearance1 #cdf1 #cdg estimation1 in altered milk1 #dhg1 #dhh butter1 #eae koumiss1 #ecd meats1 #eej preserved meats1 #efc extraction1 methods1 adapted to milk1 #dhf form of globules in milk1 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,grinding apparatus1 #f-aa ,gum1 detection1 in fermented beverages1 #fci ,gypsum1 use1 in drying sour milk1 #dhg ,gyrodynat1 definition1 #aaf ,h ,haemocyanin1 #daa ,haemoglobin1 #daa ,halle drying apparatus1 #bi ,haloid absorption by fat acids1 #cgd-cgf addition numbers1 #cfd ,heat of bromination1 improved method of determining1 #cfa-cfc ,hehner and ,mitchell1 method of determining heat of bromination1 #cfa ,richmond1 formula for calculating total solids1 #dgi1 #dhj bromin addition number1 #cgc ,hemi-peptones1 #dab ,hempel1 calorimeter1 #efi ,heteroalbumose1 #dab ,hibbard1 estimation of starch1 #bjg ,hide powder1 reagent for tannins1 #eij testing1 #eib ,honey1 composition1 #bfd ,hoppe-,seyler1 cellulose1 separation1 #cjd ,hops1 bitter principles1 #fdj substitutes1 #fdj ,horse flesh1 detection1 #eed ,hbl's process1 #cfd-cfg reagent1 preservation1 #cga ,hyalin1 #daf ,hyalogen1 #daf ,hydrochloric acid1 estimation1 in tobacco1 #fjj ,hydrogen1 drying1 #bd estimation1 in proteids1 #ddd 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,koumiss1 #ecd milk1 #bge gyrodynat1 #aai molecular weight1 #agg official method of estimation1 #bid ,laurent lamp1 #hc1 #hd polariscope1 #hc construction1 #hf-hh manipulation1 #hh ,lead acetate1 preserving agent1 #bce oxid1 separation of sugars1 #bhd1 #bhe reagent for determining oxygen absorption of oils1 #dje salts1 reagents for separating fat acids1 #cig solutions1 errors1 #ajb subacetate1 action on levulose1 #ajc ,lecithin1 extraction from seeds1 #dcj1 #dca factors for calculating1 #dca occurrence and properties1 #dcj in milk1 #dfd ,leffmann and ,beam1 method of milk fat analysis1 #eja ,legumin1 #daa ,leucin1 #dab occurrence in milk1 #dfd ,levulosazone1 #aic ,levulose1 estimation1 #afh in presence of sucrose and dextrose1 #bhj-bhe general formula for calculation1 #bgd gyrodynat1 #aai optical determination1 #bfg preparation1 #afg principles of calculation1 #bgj-bgc table for calculating from copper1 #bfj estimation1 #afi-aga ,liebermann1 method of milk fat analysis1 #dga1 #dib ,liebig ente1 #bh ,light1 kind used for polarization1 #hb ,lindet1 method of inversion1 #aji1 #aaj ,lindsey and ,holland1 digestibility of pentosans1 #efd ,lindstrm1 modification of lactocrite1 #dii ,lineolin1 #caj ,lint1 use1 in drying1 #dhf ,livache1 method of determining oxygen absorption1 #dje ,long and ,baker1 diastase preparation1 #cjj table of refractive indices1 #ccd ,mc ,mc,elroy and ,bigelow1 estimation of sugar in evaporated milks1 #bif-bih estimation of nicotin1 #fje ,mc,ilhiney1 bromin addition number1 #cgb ,m ,maercker1 apparatus for hydrolysis of starch1 #bjd method of sugar analysis1 #aec-aee ,magnesium sulfate1 reagent for precipitating proteids1 #dcc ,maize starch1 #bba ,malic acid1 estimation in fermented beverages1 #fcj1 #fca tobacco1 #fja ,malt extract1 #cja ,maltosazone1 #aic ,maltose1 estimation1 #afe gyrodynat1 #aai1 #bjf molecular weight1 #agg occurrence1 in glucose1 #bfd separation from dextrin and dextrose1 #bhg-bic table for calculating from copper1 #bfa determination1 #afe-afg ,maple sugar1 #bbh conditions of manufacture1 #bbh ,maranta starch1 #bai ,massecuites1 analysis1 #bed determination of ash1 #bef reducing sugars1 #bef water1 #bee ,maumen1 heat of sulfuric saponification1 #ceg1 #ceh ,maxwell1 method of extracting lecithin1 #dcj1 #dca ,meat extracts1 analysis1 #deb-ded composition1 #dea1 #deb ,meats1 estimation of proteids1 #eej fractional analysis1 #eeb methods of analysis1 #edi-eed sampling1 #edg scientific names1#edg ,meissl1 table for invert sugar1 #aeh ,melons1 sampling1 #egg ,melting point1 determination by spheroidal state1 #cbc-cbf methods of determining1 #cba-cbf of fats and oils1 #cbj-cbc ,mercuric compounds1 clarification1 #ajd cyanid1 reagent for destroying reducing sugars1 #bij1 #bia salts1 reagent for casein1 #ece reduction by sugar1 #aba ,metabolism1 vegetable and animal1 #b ,metalbumin1 #dae ,methyl blue1 qualitive test for invert sugar1 #aib ,micro-organisms1 occurrence in milk1 #dfi ,midzu ame1 ,japan glucose1 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specific gravity1 #bed1 #bee ,monochromatic flame1 constant1 #he ,mother beets1 determination of sugar1 #bej1 #bea ,mucic acid1 test for lactose1 #aij ,mucin1 #dad ,munroe1 thermal reactions of oils1 #cei ,muscular tissues1 occurrence in meat extracts1 #def separation of nitrogenous bodies1 #ddh-dej ,muskmelons1 composition1 #eha1 #ehb ,muter1 method of determining haloid addition1 #cgd-cgf process of separating fat acids1 #cig table1 for identifying starches1 #bad-bag ,mycsin1 #daa ,myrosin1 #daa ,n ,natural digestion1 #efb ,neuclein1 #dae ,neucleoproteids1 #dae ,neurokeratin1 #daf ,nickel prism1 #gg theory1 #gg-hj ,nicotin1 estimation in tobacco1 #fje-fjg gyrodynat1 #fjf polarization1 #fjf ,nitric acid1 color test1 fats and oils1 #cec estimation in tobacco1 #fjj qualitive test1 #dah ,nitrogen1 estimation in fermented beverages1 #fci flesh bases1 #dei proteids1 #dde of total1 #dbc percentage in proteids1 #dde ,nitrogenous bases1 occurrence in animal tissues1 #dej1 #dea bodies1 composition1 #daj estimation in meats1 #eea occurrence in animal products1 #ddh-dfb qualitive tests1 #dah-dba separation in cheese1 #ecj ,nutritive ratio1 #efh values1 #eff ,o ,oat starch1 #bba ,observation tube1 continuous1 #bec ,oil press1 #cab removal from starchy bodies1 #cjj ,oils and fats1 extraction1 #caj1 #cad identification1 #cie1 #djf physical properties1 #cag1 #cde coefficient of expansion1 #cai composition1 #cji1 #caj heat of bromination1 #cfj nomenclature1 #cji spectroscopic examination1 #cdh ,oleic acid separation from palmitic1 #cig ,olein1 #caj ,oleomargarin1 calometric distinction from butter1 #egf ,oleorefractometer1 #ccd ,oleothermometer1 #ead ,organic acids1 occurrence in ensilage1 #edf ,orseille1 detection in wines1 #fcg ,osazones1 melting points1 #aic ,ost1 copper carbonate method1 #beh1 #bei solution1 #beg ,oven1 electric1 #ai hydrogen drying1 #be1 #bg steam coil1 #bj1 #ba water jacket1 drying1 #ad ,oxalic acid1 estimation in tobacco1 #fja ,oxygen1 absorption by oils1 #dje combustion1 #efi ,p ,palm sugar1 #bbh ,palmitic acid1 separation from oleic1 #cig ,palmitin1 #caj ,pancreas extract1 digestion1 #efj peptone1 #dfa ,pancreatin digestion1 #eeh preparation1 #efj ,paraffin1 occurrence in plants1 #djd1 #dje ,paralbumin1 #dae ,patrick1 volumetric method of milk fat analysis1 #dig ,pavy's process1 #adc ,pea starch1 #bbj ,peanut oil1 detection1 #djj ,pectic acid1 estimation in tobacco1 #fjc ,pectin1 occurrence1 #egg1 #egh separation1 #egh ,pectose1 occurrence1 #egg ,pellet1 continuous observation tube1 #bec method of cold diffusion1 #bdc1 #bdd ,pentosans1 digestibility1 #efd estimation1 #agh revised factors for calculating1 #ehg ,pentose sugars1 estimation1 #agg ,pepsin digestion1 #eeh preparation1 #eeh ,peptones1 #dab qualitive tests1 #dbj1 #dba separation from albumoses1 #dee in cheese1 #eca ,permanganate gelatin1 method for tannins1 #eic1 #eid hide powder method for tannins1 #eie process1 #acb modified by ,ewell1 #acf ,peska's process1 #add 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#fcb1 #fcc ,polarized light1 #ge1 #gf application to butter analysis1 #ead relation to sugar analysis1 #gd ,politis1 method of sugar analysis1 #adh ,ponceau-red1 detection in wines1 #fcg ,potash1 estimation in wines1 #fcg ,potassium cyanid1 use in sugar analysis1 #adf hydroxid1 solvent for proteids1 #ddc nitrate1 occurrence in maize stalks1 #dag preserving agent1 #dag permanganate1 reagent for tannins1 #eic ,potato starch1 #bbj ,potatoes1 estimation of starch1 #cja1 #cjb ,powdered glass1 use in drying1 #dhf ,preserved meats1 #efc ,proteid bodies1 separation1 #dcb1 #ddh nitrogen1 estimation in tea and coffee1 #ehe qualitive test1 #dai1 #dbj ,proteids1 action of acids1 #ddb classification1 #daj diversity of character1 #dcd estimation in cereals1 #edc koumiss1 #ecd meats1 #eej milk1 #eje of digestible in cheese1 #eca general principles of separation1 #ddf insoluble1 #dac kinds in milk1 #ejd methods of drying1 #ddc1 #ddd precipitation1 #dci separation1 soluble in water1 #dci1 #ddj soluble 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number1 #eah1 #eai ,resorcin1 qualitive test for levulose1 #aia ,richmond1 thermal reaction of oils1 #cei1 #cfj ,ritthausen1 method of precipitating milk proteids1 #ejf ,roentgen rays1 application to analyses1 #ehh ,rye starch1 #bba ,s ,saccharic acid1 test for dextrose group1 #aij ,sachsse's method of determining amid bodies1 #dbd1 #dbe solution1 #abb ,saffron1 #ebb ,safranin1 detection in wines1 #fcg ,sago starch1 #bbj ,salicylic acid1 detection in fermented beverages1 #fch1 #fci ,salt1 estimation in butter1 #eaf ,samples1 collecting1 #e grinding1 #f preparation1 #c1 #d preserving1 #e ,sand1 use in drying1 #dhf ,saponification1 #cgf1 #chd chemical reactions1 #cgg1 #cgh equivalent1 #chc in the cold1 #cha1 #chb methods of conducting1 #cgh1 #chb under pressure1 #cgi1 #chj value1 #chb1 #chc of butter1 #eah with alcohol1 #cha without alcohol1 #cha ,sarkin1 #daf composition1 #dea ,sausages1 occurrence of starch1 #eec ,scheibler1 double polarization1 #ajb extraction tube1 #bdh ,schmidt1 method of milk fat analysis1 #dhi de,schweinitz and ,emery1 calorimetric distinction between butter and oleomargarin1 #egf ,schweitzer and ,lungwitz1 iodin addition1 #cfg1 #cfh ,scovell1 milk sampler1 #dgj ,selenite plate1 microscopic examination of starches1 #bai use in examination of fat crystals1 #cdc ,sesame oil1 detection1 #djb furfurol reaction1 #eba ,shadow polariscope1 #ij ,short1 method of milk fat analysis1 #dij ,shredding apparatus1 #i1 #aj1 #bcf ,sidersky1 modification of ,soldaini's process1 #adg ,sieben1 method of determining levulose1 #bhj ,silver nitrate1 color test with fats and oils1 #cee ,sirups1 analysis1 #bed determination of ash1 #bef reducing sugars1 #bef water1 #bee specific gravity1 #bed ,sodium chlorid1 reagent for extracting proteids1 #dcc thiosulfate solution1 preparation1 #cfi ,soldaini copper carbonate process1 #aci1 #adj gravimetric method1 #beh ,soleil-,ventzke polariscope1 #hh1 #hi ,solidifying point of fats and oils1 #cbf1 #cbg ,soluble acids1 estimation in butter1 #eag fat acids1 determination1 #chi1 #cij ,solvent1 recovery1 #ec1 #ee in open dish1 #ee ,solvents1 #eb1 #ec object1 #dj ,sour milk1 density1 #dgg ,soxhlet1 areometric method of milk fat estimation1 #dib1 #did extraction apparatus1 #dg ,specific gravity1 areometric method1 #gj determination in distillate1 #fae example1 #fh method of expressing1 #cai standard of comparison1 #cbj heats of materials in calorimeter1 #egc rotatory power1 #aae1 #aaf causes of variation1 #aag ,spectroscopy1 oils and fats1 #cdh ,spencer1 air-drying oven1 #ag method of estimating caffein1 #ehc observation tube1 #bec ,spheroidal state1 melting point1 #cbc1 #cbf ,sponge1 use in drying1 #dhf ,spongin1 #daf ,stannic bromate1 color test with fats and oils1 #cef ,starch1 colorimetric estimation1 #baj composition1 #aif disturbing bodies in estimation1 #bji estimation in potatoes1 #cja1 #cjb sausages1 #eec of ash1 #bjc nitrogen1 #bjc water1 #bjb1 #bii with barium hydroxid1 #bjh factor for calculating from dextrose1 #bje fixation of iodin1 #baa gyrodynat of soluble1 #bjf hydrolysis at high temperatures1 #aii in an autoclave1 #aii1 #bjj with acids1 #bjc1 #bjd occurrence1 #bih in tobacco1 #fjd particles1 separation1 #aig polarization1 #bje principles of determination1 #bja properties1 #aif rapid estimation1 #bjg separation1 #cii solution at high pressure1 #bjf in nitric acid1 #bjf ,starches1 classification1 #bah description of typical1 #bai identification1 #baa microscopic examination1 #bai occurrence in the juices of plants1 #bbh ,steam coil oven1 #bj1 #ba ,stearin1 #caj ,stone1 method of estimating pentosans1 #aha ,strontium saccharates1 #ahg ,stutzer1 artificial digestion of cheese1 #efa method of estimating gelatin1 #deg ,succinic acid1 estimation in fermented beverages1 #fcj1 #fca ,sucrose1 cobaltous nitrate test1 #ahi estimation in coffee1 #ehf presence of dextrose1 #bgd levulose and dextrose1 #bhj1 #bhe raffinose1 #bff molecular weight1 #agf occurrence1 #bfd pipette1 #bca1 #bcb qualitive optical test1 #ahh separation and estimation1 #bfd ,sugar analysis1 chemical methods1 #abj classification of methods1 #fa1 #fb general remarks1 #ajd gravimetric copper methods1 #adi1 #agj ,halle method1 #aec1 #aee laboratory gravimetric method1 #aej-aec permanganate process1 #acb-ace volumetric laboratory method1 #abi1 #acj methods1 #aba ,sugar beets1 analysis1 #bdb apparatus for grinding1 #aj extraction with alcohol1 #bde1 #bdg content in maple sap1 #bbh direct determination in canes1 #bce estimation in cane and beet pulp1 #bch sap1 #bbh-bcj sugar beets1 #bdb extraction from plants1 #bcj flask1 diffusion and alcohol digestion1 #bde ,sugar flasks1 #ih1 #ii instantaneous diffusion1 #bdc juices1 preservation1 #bce mills1 #bcj preparation of pure1 #fj removal from starchy bodies1 #cjj solutions1 preparation for polarization1 #ii-ajd specific gravity1 #fb ,sugars1 determination in dried material1 #bci without weighing1 #bec estimation in fermented beverages1 #fcb1 #fce hexose1 #ei miscellaneous qualitive tests1 #aic occurrence in tobacco1 #fjd optical properties1 #gd1 #ge pentose1 #ei qualitive tests1 #ahh separation by lead oxid1 #bhd1 #bhe state of existence in plants1 #bbg ,sulfur chlorid1 reagent for oils1 #djb1 #djc determination in proteids1 #ddf loss of organic in combustion1 #cg ,sulfuric acid1 color test for fats and oils1 #ceb estimation in tobacco1 #fjj saponification1 #ceg1 #ceh ,sulfurous acid1 elimination1 #eai estimation in fermented beverage1 #fch ,t ,tannic acid1 estimation in tobacco1 #fjd reagent for milk proteids1 #ejg ,tannin1 composition1 #ehh detection1 #ehi1 #eic estimation #ehi1 #eif by hide powder method1 #eij1 #eib infusion1 preparation1 #eif occurrence1 #ehh permanganate gelatin method1 #eic1 #eid precipitation with metallic salts1 #ehi ,tartaric acid1 estimation in wine1 #bbi1 #bcj ,tea and coffee1 #ehb ,thein1 #ehc ,thermal reactions1 fats and oils1 #cef1 #cfc ,thermostat for steam bath1 #ae ,thrner1 method of milk fat analysis1 #dia ,tobacco1 acid and basic constituents1 #eig burning qualities1 #fjh composition1 #eih1 #eii of ash1 #eih fermentation1 #eif1 #eig fractional extraction1 #fjh ,tollens and ,gnther1 method of estimating pentosans1 #ahj ,torsion ,viscosimeter1 #cdb ,total solids1 calculation1 #dgh formulas for calculating1 #dgi1 #dhj ,trinitroalbumin1 #daa ,triple shadow polariscope1 #ia1 #ib ,tropolin1 detection in wines1 #fcg ,turbidity temperature1 fats and oils1 #cea ,turmeric1 #ebb ,tyrosin1 #dab occurrence in milk1 #dfd ,tyrotoxicon1 occurrence in milk1 #dfd ,u ,ulsch1 drying oven1 #ca ,unicedin1 #dac ,urea1 occurrence1 in milk1 #dfd ,v ,vacuum1 drying1 #ah ,van ,slyke1 method of estimating casein1 #ejh ,vegetable substances1 preparation1 #c1 #d ,vegetables1 sampling1 #egg ,vinolin1 detection in wines1 #fcg ,viscosimetry1 #cdb1 #cde ,viscosity of fats and oils1 #cdb ,viscous liquids1 drying1 #cb1 #cc ,vitellin1 #daa ,vogel1 table for identifying starches1 #bab1 #bac ,volatile acids1 estimation in butter1 #eag fermented beverages1 #fbg1 #fbh bodies1 drying1 #ac fat acids1 determination1 #chf1 #chh distillation1 #chg1 #chh titration1 #chh ,volume of precipitate1 calculation1 #bgi ,w ,water1 action on composition of proteids1 #dcg estimation in butter1 #eae cereals1 #edb fermented beverages1 #fbf fruits and vegetables1 #egh koumiss1 #ecf meats1 #edi tobacco1 #eii ,watermelons1 composition1 #eha1 #ehb ,wax1 occurrence in tobacco1 #fjh ,waxes1 composition1 #cji ,westphal balance1 #fi ,wheat starch1 #bba ,wiechmann1 formula for calculating sugars1 #cjg method of estimating levulose1 sucrose and dextrose1 #bhj1 #bha ,williams1 calorimeter1 #egj ,winter1 estimation of levulose and dextrose in presence of sucrose1 #bhc1 #bhd ,wood pulp1 use in drying1 #dhf ,wrampelmayer1 drying oven1 #cj ,x ,xanthin1 #daf ,xanthoproteic reaction1 #dbj ,xylan1 occurrence1 #ehf ,y ,yeast1 inversion1 #aac ,z ,zein1 #dda ,zeiss1 butyrorefractometer1 #cci1 #cda ,zinc1 occurrence1 in evaporated fruits1 #chj1 #eha sulfate1 reagent for precipitating proteids1 #dcc separating albumoses from peptones1 #dee ,,corrections ,,for ,,vol4 ,i4 ,page #e1 #aath line1 insert 8ten0 before 8thousand40 ,page #ba1 read 8,magdeburg0 instead of 8,madgeburg0 in both instances4 ,page #fa1 for per cent4 of oxygen in ulmin read 8#bh4g0 instead of 8#h4g40 ,page #fb1 for per cent4 of carbon in apocrenic acid read 8#ed4d0 instead of 8#cd4d40 ,page #aab1 #b;d line from bottom1 read 8#ad0 instead of 8#ac40 ,page #adj1 the sentence beginning 8,the burette is lowered etc40 is repeated4 ,dele one of them4 ,page #ada1 #fth line1 insert 8or air dried0 after 8moisture40 ,page #ada1 in example read #aj4be1 #aj4bb1 #ac4jg and #gf4ba for #i4eb1 #i4bb1 #ab4jg1 and #fj4ce respectively4 ,page #aeh1 #c;d line of #agb1 insert 8and estimating soluble matters therein0 after 8flow40 ,page #aei1 omit 8 0 in first formula4 ,page #bic1 #abth line1 read 8,u0 for 8,v40 ,page #cji1 last line1 read 8sixth0 for 8sixteenth40 ,page #cab1 #ast line1 read 8atmosphere0 instead of 8room40 ,page #cae1 #fth and #gth lines1 read #bii1 and #cjj1 for #bid1 and #bie1 respectively4 ,page #cbc1 #c;d line from bottom1 read #cja for #bii4 ,page #ccc1 #eth line of #caf1 insert after 8is0 8to eliminate carbon dioxid and40 ,page #ced1 #c;d line from end of 7#f7 insert after 8solution0 8acidified with acetic and20 same line1 transfer 8r0 from 8ther10 to 8pecipitate40 ,page #ceg1 #fth line from end of 7#d7 insert after 8difference0 8and the phosphoric acid estimated as in #chj1 deducted therefrom40 ,page #cfg1 #dth line1 add after 8taken10 8,the phosphoric acid may be determined as described in #cgb1 or following paragraphs40 ,page #daj1 line #ba1 dele 8dilute0 and insert 8one per cent nitric40 ,page #daj1 line #be1 after 8capsule0 insert 8adding water once or twice40 ,page #ddi1 #dth line read 8hydrobromic0 for 8hydrochloric40 ,page #deg1 reference 8#cj0 read 8,band #ch0 instead of 8,band #cg40 ,page #dfh1 #hth line1 dele 8or gypsum0 and read 8#bjj0 instead of 8#ej40 ,page #dga1 last line1 read 8not0 for 8very40 ,page #dgb1 #dth line1 insert 8un0 before 8successful40 ,page #dif1 #eth line1 insert 8the0 before 8soil40 ,page #eae1 next to last and last lines1 read 8stannous0 instead of 8zinc40 ,page #eaf1 second line1 read 8stannous0 instead of 8zinc40 ,page #eeg1 #ith line of #ejj read 8red-yellow0 instead of 8blue40 ,,corrections ,,for ,,vol4 ,,ii4 ,page #ad1 line #ba1 read 8#fa4gd per cent40 for 8#af4gd per cent40 ,page #bc1 #hth line from bottom1 read 8#j4jjbe40 for 8#j4jjce40 ,page #ed1 #ith line1 read 8white0 instead of 8yellow40 ,page #ed1 #acth line1 read 8phosphate0 instead of 8phosphomolybdate40 ,page #eg1 #hth line from bottom1 read 8saturated0 instead of 8citrate40 ,page #gc1 read 8,kosmann0 in #ajth line of paragraph #gb for 8,kormann40 ,page #aeh1 reference number #gb1 read 8#ahhi0 instead of 8#ahhh40 ,,corrections ,,for ,,vol4 ,,iii4 ,page #aa1 name of ,figure #d read 8,dreef0 instead of 8,dree40 ,page #dj1 fifth and seventh lines1 read 8,courtonne0 instead of 8,courtoune40 ,page #ei1 eighth line from bottom1 insert 8original0 before 8optical40 ,page #fj1 second line1 read 8d0 instead of 8l0 before 8fructose40 ,page #fh1 legend of ,figure #bi1 read 8areometers0 instead of 8aereometers40 ,page #adf1 sixth line from bottom1 insert 8cyanid0 after 8potassium40 ,page #aei1 instead of headings for table as given1 substitute those on page #afj4 ,page #agg1 in formula for lactose1 read 8,h0 instead of 8,h02 in formula for arabinose1 read 8,h0 instead of 8,h40 ,page #ahj1 seventh line from bottom1 read 8,gnther0 instead of 8,gunther40 ,page #aia1 read paragraph #afi4 ,seventh line read 8resorcin0 instead of 8resorsin40 ,page #bfh1 legend of ,figure #gg1 read 8,desiccating0 instead of 8,dessicating40 ,page #bhh1 in formula 7#b7 read 8#ec;d0 instead of 8#ed;d40 ,pages #cbh1 #cbi and #ccd1 read 8,amagat0 instead of 8,armagat40 ,page #cdh1 fourth line from bottom1 omit accent in 8sesame40 ,page #cfe1 7b7 first line1 read #bd4h instead of #bd4f4 ,page #dbd1 #dth line from bottom1 read 8nitrites0 instead of 8nitrates40 ,page #dbe1 #dth and #eth lines1 read 8nitrite0 instead of 8nitrate40 ,page #dde1 in table of factors for computing proteids under ,maize ,proteids1 read 8#af4jf and #f4bb0 instead of 8#ae4fd and #f4ci0 respectively4 ,page #dea1 sixth line from bottom1 read 8occur0 instead of 8occurs40 ,page #dfd1 twelfth line from bottom1 dele 8food40 ,page #dii1 ninth line from bottom1 read 8,babcock40 ,page #edc1 sixteenth line1 read 8#f4jf and #f4bb0 for 8#f4ca and #f4ci0 respectively4 ,pages #eee-eef1 read 8amylolytic0 for 8amylytic40 ,page #eee1 fifth and seventeenth lines from bottom1 insert after 8into dextrin1 maltose40 ,page #egb1 second equation1 read 8t0 instead of 8t40 ,page #egc1 #crd line from bottom1 read 8stirring0 for 8storing40 ,page #egd1 #fth line from bottom1 read 80 for 8,o#d40 ,page #ege1 #afth line from bottom1 insert 8one gram of0 before 8substance40 ,page #egf instead of #efg1 fourth line of paragraph #eff1 read 8,calorie0 instead of 8calorie40 ,page #fdd1 dele 8,band #ab1 ,ss4 #fd und #aii0 in reference #id4