,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 ,small capitals have been converted to ,,solid capitals4 ,illustrations have been moved so they do not break up paragraphs4 ,old spellings have been preserved1 e4g4 dioxid instead of dioxide4 ,typographical and punctuation errors have been silently corrected4 ,,principles ,,and ,,practice ,,of ,,agricultural ,,analysis4 ,a ,,manual ,,for ,,the ,,estimation ,,of ,,soils1 ,,fertilizers1 ,,and ,,agricultural ,,products4 ,,for ,,the ,,use ,,of ,,analysts1 ,,teachers1 ,,and ,,students ,,of ,,agricultural ,,chemistry4 ,,volume ,,ii4 ,,fertilizers4 ,,by ,,harvey ,w4 ,,wiley1 ,,chemist ,,of ,,the ,u4 ,s4 ,,department ,,of ,,agriculture4 ,,easton1 ,,pa41 ,,chemical ,,publishing ,,co41 #ahie4 ,,copyright1 #ahie1 ,,by ,,harvey ,w4 ,,wiley4 ,,preface ,,to ,,volume ,,second4 ,in this volume an attempt has been made to treat the subject of fertilizers and fertilizing materials in the manner followed in the first volume with soils4 ,the general principles of fertilizer manufacture and application have been presented in so far as they seemed to throw light on the rational method of examination and analysis4 ,the standard methods of analysis in use in this and other countries1 have been presented with sufficient fullness for the guidance of the skilled worker1 and the information of the student4 ,to those who make use of a book only for routine work or for preparation for an examination1 this volume1 as its predecessor1 will be found to have little attraction4 ,this fact1 however1 will not be a cause of regret to the author whose purpose has been1 avowedly1 to present to the busy worker and student a broad view of a great subject which each one does not have the time to search out for himself4 ,it is a matter of regret1 however1 that the contents of the volume have again exceeded all expectations4 ,it was found impracticable to secure any greater condensation without departing from the purpose1 and impairing the completeness of the work4 ,when work is done with no prospect of financial compensation1 it is gratifying to find it appreciated1 and the author will be content to have this volume meet with as kindly a reception as has been accorded volume one4 ,,harvey ,w4 ,,wiley4 ,,washington1 ,d4 ,c41 ,end of ,july1 #ahie4 ,,table ,,of ,,contents ,,of ,,volume ,,second4 ,,part ,,first4 ,,phosphates ,,and ,,phosphatic ,,fertilizers4 ,introduction1 pp4 #a-d4--,natural fertilizers2 ,waste matters as fertilizing materials2 ,valuation of fertilizing ingredients4 ,general ,analytical ,processes1 pp4 #d-ae4--,taking samples2 ,fertilizing minerals2 ,mixed fertilizers2 ,french methods of taking samples2 ,sampling stable manures2 ,preparation of sample in laboratory2 ,french and ,german methods2 ,drying fertilizer samples2 ,moisture in acid phosphates4 ,analysis of ,mineral ,phosphates1 pp4 #ae-ci4--;,constituents to be determined2 ,direct estimation of phosphoric acid2 ,official method2 ,preparation of solution2 ,use of tartaric acid2 ,determination of water and organic matters2 ,carbon dioxid2 ,soluble and insoluble matter2 ,silica and insoluble bodies2 ,estimation of lime2 ,ammonium oxalate method2 ,immendorff method2 ,estimation of iron and alumina2 ,the acetate and ,hess methods2 ,methods of ,jones and ,crispo2 ,geological ,survey method2 ,method of ,marioni and ,fasselli2 ,method of ,krug and ,mc,elroy2 ,method of ,wyatt2 ,estimation of magnesia2 of sulfuric acid2 of fluorin4 ,general ,methods for ,phosphoric ,acid1 pp4 #ci-eg4--,preliminary considerations2 ,estimation as stannic phosphate2 ,water soluble acid2 ,citrate insoluble acid2 ,total phosphoric acid2 ,norwegian methods2 ,german experiment station methods2 ,soluble phosphoric acid2 ,swedish methods2 ,dutch methods2 ,errors in molybdate method2 ,color of pyrophosphate2 ,solution in sulfuric acid4 ,the ,citrate ,method1 pp4 #eg-gj4--;,general principles2 ,halle method2 ,swedish method2 ,methods adopted at the ,brussels ,congress2 ,dutch method for citrate soluble acid2 ,comparative accuracy of citrate and molybdate methods4 ,basic ,phosphatic ,slags1 pp4 #gj-hf4--;,history and manufacture2 ,composition2 ,molecular structure2 ,solubility2 ,separation and solution2 ,estimation of total acid2 ,alternate method2 ,halle method of analysis2 ,dutch method2 ,estimation of citrate soluble acid in basic slags2 ,wagner's shaking and digesting apparatus2 ,estimation of caustic lime in slags2 ,detection of adulteration4 ,volumetric ,determination of ,phosphoric ,acid1 pp4 #hf-ajf4--;,classification of methods2 ,uranium method2 ,preparation of sample2 ,precipitation of the phosphoric acid by magnesium citrate2 ,composition of magnesium citrate solution2 ,solution of ammonium magnesium phosphate2 ,preparation of standard solutions2 ,verifying standard solutions2 ,conduct of the analysis2 ,phosphoric acid in superphosphates2 ,determination of soluble and reverted phosphoric acid2 ,conclusions4 ,titration of the ,yellow ,precipitate1 pp4 #ajf-aah4--,pemberton's method2 ,conduct of the analysis2 ,reactions2 ,calculation of results2 ,comparison with ,official method2 ,titration as a lead compound2 ,water soluble acid2 ,estimation of phosphoric acid in presence of a large excess of iron2 ,emmerton method2 ,method of ,dudley and ,noyes2 ,the ,jones reductor2 ,the volumetric silver method4 ,technical ,determination of ,phosphoric ,acid1 pp4 #aah-abe4--;,desirability of methods2 ,reagents employed2 ,conduct of the molybdenum method2 ,conduct of the citrate method2 ,treatment of mineral phosphates and basic slags2 ,analysis of superphosphates4 ,miscellaneous ,notes on ,phosphates and ,phosphatic ,fertilizers1 pp4 #abf-aej4--,time required for precipitation2 ,examination of the pyrophosphate2 ,iodin in phosphates2 ,chromium in phosphates2 ,estimation of ,vanadium2 ,fluorin in bones2 ,note on separation of iron and alumina from phosphoric acid2 ,ammonium citrate soluble acid2 ,influence of time and strength of solvent on solution2 ,arbitrary ,determination of reverted phosphoric acid2 ,digestion apparatus of ,huston2 ,huston's mechanical stirrer2 ,citrate method with small percentage of phosphoric acid2 ,direct precipitation of the citrate soluble phosphoric acid2 ,availability of phosphatic fertilizers2 ,direct weighing of the molybdenum precipitate4 ,chemistry of the ,manufacture of ,superphosphates1 pp4 #aej-aef4--,reactions with phosphates2 with fluorids2 with carbonates2 with iron and alumina2 with magnesium compounds2 ,determination of quantity of sulfuric acid2 ,phosphoric acid superphosphates2 ,authorities cited in ,part ,first4 ,,part ,,second4 ,,nitrogen ,,in ,,fertilizers ,,and ,,fertilizing ,,materials4 ,kinds of ,nitrogen in ,fertilizers1 pp4 #afa-afi4--;,determination of state of combination2 ,microscopic examination2 ,seeds and seed residues2 ,fish scrap2 ,dried blood and tankage2 ,horn1 hoof1 and hair2 ,ammoniacal nitrogen2 ,nitrogen in guanos2 ,nitric nitrogen4 ,methods of ,analysis1 pp4 #afi-aib4--;,classification of methods2 ,official methods2 ,combustion in copper oxid2 ,official volumetric method2 ,mercury pump2 ,combustion furnace2 ,process of combustion2 ,method of ,johnson and ,jenkins2 ,calculating results2 ,reading barometer2 ,tension of aqueous vapor2 ,aqueous tension in solutions of potassium hydroxid2 ,tables for calculating results2 ,soda-lime process2 ,official ,french method2 ,the ruffle soda-lime method2 ,official ruffle method2 ,boyer's ruffle method4 ,moist ,combustion ,process1 pp4 #aib-bbj4--;,historical2 ,method of ,kjeldahl2 ,theory of the reactions2 ,preparation of reagents2 ,dutch kjeldahl method2 ,halle kjeldahl method2 ,official kjeldahl method2 ,distillation apparatus2 ,patrick's distilling flask2 ,modification of the kjeldahl process2 ,method of ,wilfarth2 ,method of ,asboth2 ,method of ,jodlbaur2 ,dutch jodlbaur method2 ,halle jodlbaur method2 ,official method for nitric nitrogen2 ,method of ,scovell2 ,gunning method2 ,reactions of the gunning method2 ,official gunning method2 ,gunning method adapted to nitrates4 ,determination of ,nitrogen in ,definite ,forms of ,combination1 pp4 #bba-bca4--;,introductory considerations2 ,nitrogen as ammonia2 ,method of ,boussingault2 ,determination of thiocyanates2 ,separation of albuminoid nitrogen2 ,separation of nitric nitrogen2 ,separation of ammoniacal nitrogen2 ,ulsch method for mixed fertilizers2 ,method of ,schlesing-,wagner2 ,schmitt's modified method2 ,krger's method4 ,sodium ,nitrate1 pp4 #bca-bdg4--;,functions of sodium nitrate2 ,commercial forms of ,chile saltpeter2 ,percentage of nitrogen in ,chile saltpeter2 ,adulteration of ,chile saltpeter2 ,the ,halle zinc-iron method for estimating nitrogen in ,chile saltpeter2 ,french method2 ,gantter's volumetric method2 ,method of difference2 ,application of ,chile saltpeter to the soil2 ,taking samples of soil to determine nitric nitrogen2 ,the nitrifiable solution2 ,quantity of ,chile saltpeter per acre2 ,consumption of ,chile saltpeter2 ,authorities cited in ,part ,second4 ,,part ,,third4 ,potash in ,fertilizing ,materials and ,fertilizers1 pp4 #bdh-bff4--;,introduction2 ,forms of potash2 ,organic sources of potash2 ,tobacco stems and waste2 ,cottonseed hulls and meal2 ,wood ashes2 ,fertilizing value of ashes2 ,sugar beet molasses2 ,residue of wineries2 ,destruction of organic matter2 ,ignition with sulfuric acid2 ,potash in mineral deposits2 ,occurrence and history2 ,changes in potash salts in situ2 ,kainit2 ,carnallit2 ,polyhalit2 ,krugit2 ,sylvin2 ,sylvinit2 ,kieserit2 ,schnit2 ,potassium sulfate2 ,potassium magnesium carbonate2 ,potash in factory residues2 ,quantity of potash salts used4 ,methods of ,analysis1 pp4 #bff-bhi4--;,classification of methods2 ,platinic chlorid method2 ,official method2 ,alternate official method2 ,solution of organic compounds2 ,factors for calculation2 ,halle potash method2 ,dutch method2 ,swedish method2 ,method of the ,german ,kali syndicate2 ,method for high grade potash salts2 ,barium oxalate method2 de ,roode method for kainit2 ,calcium chlorid method2 ,rapid control method2 ,determination from metallic platinum2 ,errors in platinum method2,effect of concentration on accuracy2 ,differences in form of crystals of potassium platinochlorid2 ,recovery of the platinum waste4 ,estimation of ,potash as ,perchlorate1 pp4 #bhi-cja4--;,general principles2 ,caspari's method of preparing perchloric acid2 ,kreider's method2 ,keeping properties of perchloric acid2 ,the analytical process for determining potassium as perchlorate2 ,removal of sulfuric acid2 ,applicability of the process2 ,accuracy of the process2 ,authorities cited in ,part ,third4 ,,part ,,fourth4 ,miscellaneous ,fertilizers1 pp4 #cjb-cbd4--;,classification2 ,forms of lime2 ,application of lime2 ,action of lime2 ,analysis of lime2 ,gypsum1 or land plaster2 ,analysis of gypsum2 ,common salt2 ,green vitriol2 ,stall manures2 ,hen manure2 ,guanos and cave deposits2 ,official ,french method for phosphoric acid in guanos2 ,leather waste2 ,wood ashes2 ,analysis of wood ashes2 ,method of analysis used in this laboratory2 ,official method for estimating alkalies in wood ashes2 ,statement of results2 ,authorities cited in ,part ,fourth2 ,index4 ,,illustrations ,,to ,,volume ,,second4 ,page4 ,figure #a4 ,apparatus for crushing mineral fertilizers #e 8 #b4 ,plate grinder for minerals #f 8 #c4 ,shaking apparatus for superphosphates #fj 8 #d4 ,shaking machine for ammonium magnesium phosphate #fd 8 #e4 ,rssler ignition furnace #fe 8 #f4 ,wagner's digestion apparatus for slags #gi 8 #g4 ,jones' reduction tube #aae 8 #h4 ,huston's digesting apparatus #adb 8 #i4 ,huston's mechanical stirrer #ade 8 #aj4 ,mercury pump and azotometer #agd 8 #aa4 ,moist combustion apparatus of the ,halle agricultural laboratory #bja 8 #ab4 ,distillation apparatus of ,halle agricultural laboratory #bjc 8 #ac4 ,distilling apparatus #bjh 8 #ad4 ,schlesing-,wagner apparatus #bbi 8 #ae4 ,halle nitric acid apparatus #bcd 8 #af4 ,gantter's nitrogen apparatus #bcg 8 #ag4 ,geological relations of the potash deposits near ,stassfurt #beh ,,volume ,,second4 ,,examination ,,of ,,fertilizing ,,materials1 ,,fertilizers1 ,,and ,,manures4 ,,part ,,first4 ,,preliminary ,,treatment ,,and ,,phosphates4 #a4 ,introduction4--,in the first volume the principal plant foods occurring in soils have been named and the methods of estimating them described4 ,as fertilizers are classed those materials which are added to soils to supply supposed deficiencies in plant foods1 or to render more available the stores already present4 ,there is little difference between the terms fertilizer and manure4 ,in common language the former is applied to goods prepared for the farmer by the manufacturer or mixer1 while the latter is applied to the stores accumulated about the stables or made elsewhere on the farm4 ,thus it is common to speak of a barnyard or stall manure and of a commercial fertilizer4 ,one of the objects of the analysis of soils1 as described in the first volume of this work1 is to determine the character of the fertilizer which should be added to a field in order to secure its maximum fertility4 ,one purpose of the present part is to determine the fitness of offered fertilizing material to supply the deficiencies which may be revealed by a proper study of the needs of the soil4 #b4 ,natural ,fertilizers4--,in the succession of geologic epochs which has marked the natural history of the earth there have been brought together in deposits of greater or less magnitude the stores of plant food unused by growing crops or which may once have been part of vegetable and animal organisms4 ,some of these deposits have been mentioned in the first volume1 paragraphs #aa1 #ab1 and #ah4 ,for a full description of the extent and origin of these deposits the reader is referred to works on economic geology4 ,these deposits are the chief sources of the commercial fertilizers which are offered to the farmers of to-day and to which the agricultural analyst is called upon to devote much of his time and labor4 ,the methods of determining the chemical composition and agricultural value of these deposits1 as practiced by the leading chemists of this country and ,europe1 will be fully set forth in the following pages4 #c4 ,waste ,matters as ,fertilizing ,materials4--,in addition to the natural products just mentioned the analyst will be called on also to deal with a great variety of waste materials which1 in the last few years1 have been saved from the dbris of factories and abattoirs1 and prepared for use on the farm4 ,among these waste matters may be mentioned1 bones1 horns1 hoofs1 hair1 tankage1 dried blood1 fish scrap1 oil cakes1 ashes1 sewage1 and sewage precipitates1 offal of all kinds1 leather scraps1 and organic dbris in general4 ,it is important1 before beginning an analysis1 to know the origin of the substances to be determined4 ,as has already been pointed out in volume first the process which would be accurate with a substance of a mineral origin might lead to error if applied to the same element in organic combination4 ,this is particularly true of phosphorus and potash4 ,a simple microscopic examination will usually enable the analyst to determine the nature of the sample4 ,in this manner1 in the case of a phosphate1 it would at once be determined whether it was bone1 mineral1 or basic slag4 ,the odor1 color1 and general consistence will also aid in the determination4 #d4 ,valuation of ,fertilizing ,ingredients4--,perhaps there are no more numerous and perplexing questions propounded to the analyst than those which relate to the value of fertilizing materials4 ,there is none harder to answer4 ,as a rule these questions are asked by the farmer1 and refer to the fertilizers put down on his fields4 ,in such cases the cost of transportation is an important factor in the answer4 ,the farther the farmer is removed from the place of fertilizer manufacture the greater1 as a rule1 will be the cost4 ,whether the transportation is over land or by water also plays an important part in the final cost4 ,the discovery of new stores of fertilizing materials has also much to do with the price4 ,this fact is especially noticeable in this country1 where the price of crude phosphates at the mines has fallen in a few years from nearly six dollars to three dollars and forty-three cents per ton#a4 ,this decrease has been largely due to discoveries of vast beds of phosphatic deposits in ,florida1 ,north ,carolina1 ,tennessee1 and ,virginia4 ,the state of trade1 magnitude of crops1 and the vigor of commerce also affect1 in a marked degree1 the cost of the raw materials of commercial fertilizers4 #e4 ,trade ,values of ,fertilizing ,ingredients in ,raw ,materials and ,chemicals4--,the values proposed by the ,massachusetts ,experiment ,station are given below4#b ,cents per pound4 ,nitrogen in ammonia salts1 #ai 8 8 nitrates1 #ad ,organic nitrogen in dry and fine-ground fish1 meat1 blood1 and in high-grade mixed fertilizers1 #ah 8 8 8 cottonseed meal1 linseed meal1 and castor pomace1 #ae 8 8 8 fine-ground bone and tankage1 #af 8 8 8 fine-ground medium bone and tankage1 #ae 8 8 8 medium bone and tankage1 #ab 8 8 8 coarse bone and tankage1 #g 8 8 8 hair1 horn shavings1 and coarse fish scraps1 #g ,phosphoric acid soluble in water1 #f 8 8 soluble in ammonium citrate1 #e 8 8 in fine bone and tankage1 #e 8 8 in fine medium bone and tankage1 #d 8 8 in medium bone and tankage1 #c 8 8 in coarse bone and tankage1 #b 8 8 in fine-ground fish1 cottonseed meal1 linseed meal1 castor pomace1 and wood-ashes1 #e 8 8 insoluble 7in ammonium citrate7 in mixed fertilizers1 #b ,potash as high-grade sulfate1 and in mixtures free from muriate1 #e 8 8 muriate1 #d ,the manurial constituents contained in feed stuffs are valued as follows3 ,organic nitrogen1 #ae ,phosphoric acid1 #e ,potash1 #e ,the organic nitrogen in superphosphates1 special manures1 and mixed fertilizers of a high grade is usually valued at the highest figures laid down in the trade values of fertilizing ingredients in raw materials2 namely1 eighteen and one-half cents per pound1 it being assumed that the organic nitrogen is derived from the best sources2 viz41 animal matter1 as meat1 blood1 bones1 or other equally good forms1 and not from leather1 shoddy1 hair1 or any low-priced1 inferior form of vegetable matter1 unless the contrary is evident4 ,in such materials the insoluble phosphoric acid is valued at two cents a pound4 ,these values change as the markets vary4 ,the scheme of valuation prepared by the ,massachusetts station does not include phosphoric acid in basic slags4 ,by many experimenters the value of the acid in this combination1 tetracalcium phosphate1 is fully equal to that in superphosphates soluble in water and ammonium citrate4 ,it would perhaps be safe to assign that value to all the phosphoric acid in basic slags soluble in a five per cent citric acid solution4 ,untreated fine-ground phosphates1 especially of the soft variety1 so abundant in many parts of ,florida1 have also a high manurial value when applied to soils of an acid nature or rich in humus4 ,on other soils of a sandy nature1 or rich in calcium carbonate1 such a fertilizer would have little value4 ,the analyst in giving an opinion respecting the commercial value of a fertilizer1 must be guided not only by the source of the material1 its fineness or state of decomposition1 and its general physical qualities1 but also by the nature of the crop which it is to nourish and the kind of soil to which it is to be applied4 ,,general ,,analytical ,,processes4 #f4 ,taking ,samples4--,it is impracticable to give definite directions for taking samples of fertilizers which will be applicable to all kinds of material and in all circumstances4 ,if the chemist himself have charge of the taking of the sample1 it will probably be sufficient to say that it should accurately represent the total mass of material sampled4 ,generally the samples which are brought to the chemist have been taken without his advice or direction and he is simply called upon to make an analysis of them4 ,illustration3 ,,figure #a4 ,,apparatus ,,for ,,crushing ,,mineral ,,fertilizers4 #g4 ,minerals ,containing ,fertilizing ,materials4--,when possible1 the samples should be accompanied by a description of the mines where they are procured and a statement of the geologic conditions in which the deposits were made4 ,as large a quantity of the material as can be conveniently obtained and transported should be secured4 ,where a large quantity of mineral matter is at hand it should first be put through a crusher4 ,many forms of crusher1 driven by hand and other power1 are on the market4 ,among these may be mentioned the ,alden1 ,blake1 ,bisworth1 ,forster1 and ,lipsay machines4#c ,they are all constructed essentially on the same principle1 the pieces of mineral being broken into small fragments between two heavy vibrating steel plates4 ,the general form of these instruments is seen in ,fig4 #a4 ,the fragments coming from the crusher can be reduced to a coarse powder by means of the iron plate and crusher shown in ,fig4 #b4 ,where only a small quantity of mineral is at hand the apparatus just mentioned may be used at once after breaking the sample into small fragments by means of a hammer4 ,finally the sample1 if to be dissolved in an acid or soluble materials only1 is reduced to a powder in an iron mortar until it will pass a sieve with a one or1 better1 one-half millimeter circular mesh4 ,the powder thus obtained must be stirred with a magnet to remove all iron particles that may have been incorporated with the mass by abrasion of the instruments employed4 ,if a complete mineral analysis of the sample is to be secured1 the material freed from iron1 as above described1 is to be rubbed to an impalpable powder in an agate mortar4 ,illustration3 ,,figure #b4 ,,plate ,,grinder ,,for ,,minerals4 #h4 ,mixed ,fertilizers4--,in fertilizing materials in bulk1 the first requisite is that they shall be thoroughly mixed so that a given volume of the material may represent1 practically1 definite quantities of the materials sampled4 ,the finer the material is1 in the original state1 and the more thoroughly it has been mixed1 the better the sample will be4 ,if the sample be already in sacks it will be sufficient to take portions by means of the ordinary trier1 such as is used for sampling sugar and other substances4 ,this consists of a long metal implement such as would be formed by a longitudinal section of a tube4 ,the end is pointed and suited for penetrating into the sack and the materials contained therein4 ,on withdrawing it1 the semi-circular concavity is found filled with the material sampled4 ,samples in this way should be taken from various parts of the sack and these samples well mixed together and a subsample of the amount necessary to be taken to the laboratory can then be obtained4 #i4 ,method of the ,french ,experiment ,stations4--,in the method employed by the ,french ,experiment ,stations it is directed that in no case should stones or other foreign particles be removed from the fertilizer sampled1 but they should enter into the sample taken in1 as nearly as possible1 the same proportions as they exist in the whole mass4 ,in the case of stones or other solid masses which are to be sampled1 as many samples as possible should be taken from all parts of the heap and these should be reduced to a coarse powder1 thoroughly mixed together and sampled4 ,in case the material is in the form of a paste1 if it is homogeneous1 it will be sufficient to mix it well and take the sample directly2 but in case there is a tendency for the pasty mass to separate into two parts1 of which the one is a liquid and the other1 more of a solid consistence1 it may be well to take samples from each in case they can not be thoroughly incorporated by stirring4 #aj4 ,method of the ,french ,association of ,sugar ,chemists4--,the method adopted by the ,french sugar chemists directs that the sample should be taken from the fertilizer in bulk or from a portion used for industrial purposes4#d ,the sample for analysis is to be taken from the above sample after it has been sent to the laboratory4 ,the method of taking should be varied according to the condition of the substances to be analyzed4 ,the large sample selected from the goods delivered to commerce having been delivered at the laboratory1 the analytical sample is taken as follows3 ,when the industrial sample1 more or less voluminous1 reaches the laboratory1 the chemist is to begin by taking a note of the marks1 labels1 and descriptions found thereon1 and of the nature and state of the package which contains it1 and the date of its arrival4 ,all this information should be entered upon the laboratory book and afterwards transcribed on the paper containing the results of the analysis1 as well as the name of the person sending it4 ,this having been done1 the sample is to be properly prepared in order that a portion may be taken representing exactly the mean composition of the whole4 ,if it is in a state of fine powder1 such as ground phosphates and certain other fertilizers1 it is sufficient to pass it two or three times through a sieve with meshes one millimeter in diameter1 taking care to break up the material each time in order to mix it and to pulverize the fragments which the sieve retains4 ,the whole is afterwards spread in a thin layer upon a large sheet of paper1 and a portion is taken here and there upon the point of a knife until about twenty grains are removed1 and from this the portion subjected to analysis is afterwards taken4 ,if the sample comes in fragments1 more or less voluminous1 such as phosphatic rocks or coarsely pulverized guanos containing agglomerated particles1 it is necessary first to reduce the whole to powder by rubbing it in a mortar or in a small drug mill4 ,it is next passed through a sieve of the size mentioned above and that which remains upon the sieve pulverized anew until all has passed through4 ,this precaution is very important1 since the parts which resist the action of the pestle the most have often a composition different from those which are easily broken4 ,when the products to be analyzed contain organic materials1 such as horn1 flesh1 dry blood1 etc41 the pulverization is often a long and difficult process1 and results in a certain degree of heating which drives off some of the moisture in such a way that the pulverized product is at the last drier1 and1 consequently1 richer than the primitive sample4 ,it is important to take account of this desiccation1 and since the pulverization of a mass so voluminous can not be made without loss1 the determination of the total weight of the sample before and after pulverization does not give exact results4 ,in such a case it is indispensable to determine the moisture1 both before and after pulverizing1 and to calculate the analytical results obtained upon the pulverized sample back to the original sample4 ,in order to escape this necessity1 as well as the difficulties resulting from the variations in moisture during transportation1 some chemists have thought it better to always dry the commercial products before submitting them to analysis1 and to report their results in the dry state1 accompanied by a determination of the moisture1 leaving thus to the one interested the labor of calculating the richness in the normal state1 that is to say1 in the real state in which the merchandise was delivered4 ,in addition to the fact that this method allows numerous chances of errors1 many substances undergoing important changes in their composition by drying alone1 it has been productive of the most serious consequences4 ,the sellers have placed their wares on the market with the analysis of the material in a dry state1 and a great number of purchasers have not perceived the fraud concealed under this expression so innocent in appearance4 ,it is thus that there has been met with in the markets guano containing twenty-five per cent of water1 which was guaranteed to contain twelve per cent of phosphoric acid1 when1 in reality1 it contained only eight per cent in the moist state4 #aa4 ,barn-,yard ,manures4--,the sampling of stall and barnyard manures is more difficult on account of the fact that the materials are not homogeneous and that they are usually mixed with straw and other dbris from the feed trough1 and only the greatest care and patience will enable the operator to secure a fair sample4 ,in the case of liquid manures the liquid should be thoroughly stirred before the sample is taken4 ,frear points out the difficulty of securing representative samples of stall manure and describes methods of removing it4#e ,the stall manure sampled had been piled in the cattle-yard for a time and the cattle were allowed to run over the heaps for an hour or two each day4 ,pigs were also allowed free access to the heaps in order to insure a more perfect mixture of the ingredients4 ,twenty-nine loads of #c1jjj pounds each were taken from the exposed heap and thirty-four loads of #b1jjj pounds each were taken from the covered heap4 ,from each load were removed two carefully selected portions of ten pounds each1 which were placed in separate covered boxes numbered ,a and ,b4 ,when the sampling was completed these boxes were covered4 ,after being removed to the laboratory the boxes were weighed and the contents thoroughly mixed4 ,two samples of twelve liters volume each1 were drawn from each box4 ,one-third of this was chopped in a large meat chopper and the other two-thirds taken into the laboratory without being cut4 ,these samples1 on entering the laboratory1 were weighed and dried at a temperature of #fj4 ,smaller samples were then drawn from each of these and ground in a drug mill for analysis4 ,duplicate samples taken in this way1 while they did not give absolutely concordant results1 showed a near approximation4 ,a more careful sampling on the line proposed would1 in all probability1 secure absolutely agreeing results in duplicate samples4 #ab4 ,preparation of ,sample in ,laboratory4--,the method of preparing mineral fertilizers for analysis has been given under directions for sampling4 ,many difficulties attend the proper preparation of other samples1 and the best approved methods of procedure are given below3 ,according to the directions given by the ,association of ,official ,agricultural ,chemists the sample should be well intermixed1 finely ground1 and passed through a sieve having circular perforations one millimeter in diameter4#f ,the processes of grinding and sifting should take place as rapidly as possible so that there may be no gain or loss of moisture during the operation4 #ac4 ,method of the ,french ,agricultural ,stations4--,the manner of proceeding recommended by the ,french stations varies with the fertilizer4#g ,if it is not already in the form of a powder it is necessary to pulverize it as finely as possible by rubbing it up in a mortar4 ,in certain cases1 as with superphosphates1 the material should be passed through a sieve having apertures of one millimeter diameter1 all the larger parts being pulverized until they will pass this sieve4 ,when the matters are too pasty to be divided in the mortar they should be divided by means of a knife or a spatula4 ,they should then be incorporated with a known weight of inert1 pulverulent matter such as fine sand1 with which they should be thoroughly mixed and in subsequent calculations the quantity of sand or other inert matter added must be taken into consideration4 ,usually a pasty state of a fertilizer is due to the humidity of the mixture4 ,in this case a considerable volume of the sample is taken and dried and then reduced to a pulverulent state4 ,in the subsequent calculations1 however1 the percentage of moisture lost must be taken into consideration4 ,before drying a sample it is necessary to take into consideration whether or not the product will be modified by desiccation as would be the case1 for instance1 with superphosphates4 ,with these1 which are often in a state more or less agglomerated1 it is recommended to introduce into them1 in order to divide them1 a certain quantity of calcium sulfate in order to obtain them in a pulverulent state4 ,in the case of animal dbris they should be divided as finely as possible with the aid of scissors and then passed through a drug mill if dry enough4 ,they are then mixed by hand and may finally be obtained in a state of considerable homogeneity4 ,when fertilizers are in a pasty state more or less liquid1 they are dried at #ajj1 first introducing a little oxalic acid in case they contain any volatile ammoniacal compounds4 ,the product of desiccation is then passed through a mill4 ,before treating in this way it is necessary to be sure that the composition will not be altered by drying4 ,in the case of a mixture containing superphosphates and nitrate1 for instance1 drying would eliminate the nitric acid4 ,in such a case the free phosphoric acid should be neutralized with a base like lime4 ,in the case of fertilizers containing both nitrates and volatile ammoniacal compounds the addition of oxalic acid might also set free nitric acid during the desiccation4 ,in such a case it is necessary to dry two samples2 one with the addition of oxalic acid for the purpose of estimating the ammonia1 and the other without the acid for the purpose of estimating the nitrate4 ,a qualitative analysis should precede all the operations so as to determine the nature of the material to be operated on4 #ad4 ,german ,method4--,in the method pursued by the ,german experiment stations it is directed3#h 7#a7 ,dry samples of fertilizers must be passed through a sieve and afterwards well mixed4 7#b7 ,with moist fertilizers1 which can not be subjected to the above process1 the preparation should consist in a careful and thorough mixing1 without sieving4 7#c7 ,on the arrival of the samples in the laboratory their weight should be determined4 ,the half of the sample is prepared for analysis and the other part1 to the amount of a kilo1 should be placed in a glass vessel1 closed air-tight1 and placed in a cool place for at least a quarter of a year from the time of its reception1 in order that it may be subjected to any subsequent investigations which may be demanded4 7#d7 ,in the case of raw phosphates and bone-black the amount of water which they contain should be determined at from #aje to #aaj4 ,samples which in drying lose ammonia in any way1 should have this ammonia determined4 7#e7 ,samples which are sent to other laboratories for control analyses1 should be sent securely packed in air-tight glass bottles4 7#f7 ,the weight of the samples sent should be entered in the certificates of analysis4 7#g7 ,samples which1 on pulverizing1 change their content of water1 must have the water content estimated in both the coarse and powdered condition and the results of the analysis must be calculated to the water content of the original coarse substance4 #ae4 ,special ,cases4--,many cases arise of such a nature as to make it impossible to lay down any rule which can be followed with success4 ,as in almost every other process in agricultural chemistry the analyst in such cases must be guided by his judgment and experience4 ,keeping in view the main object1 viz41 to secure in a few grams of material a fair representation of large masses he will generally be able to reach the required result by following the broad principles already outlined4 ,in many cases the details of the work and the adaptations necessary to success must be left to his own determination4 #af4 ,drying ,samples of ,fertilizers4--,the determination of the uncombined moisture in a sample of fertilizer is not an easy task4 ,in some cases1 as in powdered minerals1 drying to constant weight at the temperature of boiling water is sufficient4 ,in organic matters containing volatile nitrogenous compounds1 these must first be fixed by oxalic or sulfuric acid1 before the desiccation begins4 ,if any excess of sulfuric acid be added1 however1 drying at #ajj becomes almost impossible4 ,particular precautions must be observed in drying superphosphates4 ,in drying samples preparatory to grinding for analysis1 it is best to stop the process as soon as the materials can be pulverized4 ,in general1 samples should be dried only to determine water1 and the analytical processes should be performed on the undried portions4 ,it is not necessary1 as a rule1 to dry samples of fertilizers in an inert atmosphere1 such as hydrogen or carbon dioxid4 ,drying in vacuo may be practiced when it is desired to secure a speedy desiccation or one at a low temperature4 #ag4 ,official ,methods4--,the ,official ,agricultural ,chemists direct1 in the case of potash salts1 sodium nitrate1 and ammonium sulfate1 to heat from one to five grams in a flat platinum or aluminum dish at #acj until the weight is constant4#i ,the loss in weight is taken to represent the water4 ,in all other cases heat two grams1 or five grams if the sample be very coarse1 for five hours in a steam-bath4 ,in the ,german stations in the case of untreated phosphates and bone-black the moisture is estimated at from #aje to #aaj4 ,samples which lose ammonia should have the weight of ammonia given off at that temperature1 determined separately4 ,for purposes of comparison it would be far better to have all contents of moisture determined at the boiling-point of water4 ,while this varies with the altitude and barometric pressure yet it is quite certain that the loss on drying to constant weight at all altitudes is practically the same4 ,where the atmospheric pressure is diminished for any cause the water escapes all the more easily4 ,this1 practically1 is a complete compensation for the diminished temperature at which water boils4 ,where the samples contain no ingredient capable of attacking aluminum1 they can be conveniently dried1 in circular dishes of this metal about seven centimeters in diameter and one centimeter deep1 to constant weight1 at the temperature of boiling water4 #ah4 ,moisture in ,monocalcium ,phosphates4--,in certain fertilizers1 especially superphosphates1 containing the monocalcium salt1 the estimation of water is a matter of extreme difficulty on account of the presence of free acids and of progressive changes in the sample due to different degrees of heat4 ,stoklasa has studied these changes and reaches the following results#aj3 ,a chemically pure monocalcium phosphate of the following composition1 viz41 ,ca,o #bb4cf per cent4 ,p,o #ef4fg 8 8 ,h,o #ba4ec 8 8 was subjected to progressive dryings4 ,the loss of water after ten hours was #a4hc per cent2 after twenty hours1 #b4df per cent2 after thirty hours1 #e4ba per cent2 after forty hours1 #f4cb per cent2 after fifty hours1 #f4dc per cent4 ,this loss of water remained constant at #f4dc per cent4 ,this loss represents one molecule of water as compared with the total molecular magnitude of the mass treated4 ,a calcium phosphate1 therefore1 of the following composition1 ,ca,h7,,po7,h,o loses1 after forty hours1 drying at #ajj1 its water of crystallization4 ,the calcium phosphate produced by this method forms opaque crystals which are not hygroscopic and which give1 on analysis1 the following numbers3 ,ca,o #bd4jb per cent4 ,p,o #af4gd 8 8 ,h,o #ae4ji 8 8 ,the temperature can be raised to #aje without marked change4 ,if the temperature be raised to #bjj the decomposition of the molecule is hastened according to the following formula3 #d ,ca,h7,,po7 ,ca,p,o ,ca7,,po7 ,ca,h,p,o #b ,h,,po #d ,h,o4 ,the chemical changes during the drying of monocalcium phosphates can be represented as follows1 temperature #bjj for one hour3 #h;,ca,h7,,po7,h,o #d;,ca,h7,,po7 ,ca7,,po7 ,ca,p,o ,ca,h,p,o #b;,h,,po #ab;,h,o4 ,the further drying at #bjj produces the following decomposition3 #d;,ca,h7,,po7 ,ca7,,po7 ,ca,p,o ,ca,h,p,o #b;,h,,po #b;,ca7,,po7 #d;,ca,h,p,o ,ca,p,o #b;,h,,po #e;,h,o4 #b;,ca7,,po7 #d;,ca,h,p,o ,ca,,po #b;,h,,po #f;,ca7,,po7 #b;,ca,h,p,o #e;,h,o4 ,finally1 pyrophosphate at #baj is completely decomposed into metaphosphate and water according to the following formula3 #f;,ca7,,po7 #b;,ca,h,p,o #h;,ca7,,po7 #b;,h,o4 ,provided the drying is made at once at #baj the sum of the changes produced as indicated above1 can be represented by the following formula3 #h;,ca,h7,,po7,h,o #h;,ca7,,po7 #bd;,h,o4 ,,complete ,,analysis ,,of ,,mineral ,,phosphates4 #ai4 ,constituents to be ,determined4--,the most important point in the analysis of mineral phosphates is to determine their content of phosphoric acid4 ,of equal scientific interest1 however1 and often of great commercial importance is the determination of the percentage of other acids and bases present4 ,the analyst is often called on1 in the examination of these bodies1 to make known the content of water both free and combined1 of organic and volatile matter1 of carbon dioxid1 sulfur1 chlorin1 fluorin1 silica1 iron1 alumina1 calcium1 manganese1 magnesia1 and the alkalies4 ,the estimation of some of these bodies presents problems of considerable difficulty1 and it would be vain to suppose that the best possible methods are now known4 ,especially is this the case with the processes which relate to the estimation of the fluorin1 silica1 iron1 alumina1 and lime4 ,the phosphoric acid1 however1 which is the chief constituent from a commercial point of view1 it is believed1 can now be determined with a high degree of precision4 ,often the estimation of some of the less important constituents is of great interest in determining the origin of the deposits1 especially in the case of fluorin4 ,while the merchant is content with knowing the percentage of phosphoric acid and the manufacturer asks in addition only some knowledge of the quantity of iron1 alumina1 and lime the analyst in most cases is only content with a complete knowledge of the constitution of the sample at his disposal4 #bj4 ,direct ,estimation of the ,phosphoric ,acid4--,it often happens1 in the case of a mineral phosphate1 that the only determination desired is of the phosphoric acid4 ,in this instance the analyst may proceed as follows3 ,if the qualitative test shows the usual amount of phosphoric acid1 two grams of the sample passed through a sieve1 with a millimeter mesh1 are placed in a beaker and thoroughly moistened with water4 ,the addition of water is to secure an even action of the hydrochloric acid on the carbonates present4 ,the beaker is covered with a watch-glass and a little hydrochloric acid is added from time to time until all effervescence has ceased4 ,there are then added about thirty cubic centimeters of aqua regia and the mixture raised to the boiling-point on a sand-bath or over a lamp4 ,the heating is continued until chlorin is no longer given off and solution is complete4 ,the volume of the solution is then made up to #bjj cubic centimeters without filtering1 filtered1 and an aliquot part of the filtrate1 usually fifty cubic centimeters1 representing half a gram of the original sample1 taken for the determination of the phosphoric acid according to the method of the ,official ,agricultural ,chemists4 ,the small quantity of insoluble material does not introduce any appreciable error into the process when the volume is made up to #bjj or #bej cubic centimeters4 #ba4 ,method of the ,official ,agricultural ,chemists for ,total ,phosphoric ,acid4--,to the hot solution1 for every decigram of phosphorus pentoxid which may be present1 add fifty cubic centimeters of the molybdic solution4 ,digest at #fe for an hour1 filter1 and wash with water or ammonium nitrate solution#aa4 ,test the filtrate by renewed digestion with additional molybdate reagent4 ,dissolve the precipitate on the filter with ammonia in hot water and wash into a beaker1 making the volume of filtrate and washings not more than #ajj cubic centimeters4 ,nearly neutralize with hydrochloric acid1 cool1 and add magnesia mixture from a burette at the rate of about one drop a second1 stirring vigorously1 meanwhile4 ,the quantity of magnesia mixture to be added is not prescribed in the official method but it should always be in excess of the amount necessary for complete precipitation4 ,for each decigram of phosphorus pentoxid1 from eight to ten cubic centimeters should be used4 ,fifteen minutes after the last of the magnesia mixture has been stirred in1 thirty cubic centimeters of ammonia of #j4ie specific gravity are added and the beaker set aside for two hours or longer4 ,the ammonium magnesium phosphate is separated by filtration1 dried1 ignited gently at first1 and finally over a blast-lamp and weighed as magnesium pyrophosphate4 ,the factors for calculating the phosphorus pentoxid and tricalcium phosphate from the weight of pyrophosphate are given below on the two bases2 viz41 hydrogen equals #a1 and oxygen equals #af4 ,h #a4 ,mg,p,o #j4fcigf ,p,o ,mg,p,o #a4cifd ,ca7,,po7 ,p,o #b4ahbg ,ca7,,po7 ,o #af4 ,mg,p,o #j4fcgib ,p,o ,mg,p,o #a4cibf ,ca7,,po7 ,p,o #b4ahca ,ca7,,po7 #bb4 ,preparation of ,solutions4--,molybdic ,solution4--,dissolve #ajj grams of molybdic acid in #djj grams or #dag cubic centimeters of ammonia1 of #j4if specific gravity1 and pour the solution thus obtained into #a1ejj grams or #a1bej cubic centimeters of nitric acid1 of #a4bj specific gravity4 ,keep the mixture in a warm place for several days1 or until a portion heated to #dj deposits no yellow precipitate of ammonium phosphomolybdate4 ,decant the solution from any sediment and preserve in glass-stoppered vessels4 ,magnesia ,mixture4--,dissolve twenty-two grams of recently ignited calcined magnesia in dilute hydrochloric acid1 avoiding an excess of the latter4 ,add a little calcined magnesia in excess1 and boil a few minutes to precipitate iron1 alumina1 and phosphoric acid2 filter1 add #bhj grams of ammonium chlorid1 #gjj cubic centimeters of ammonia of specific gravity #j4if1 and water enough to make a volume of two liters4 ,instead of the solution of twenty-two grams of calcined magnesia1 #aaj grams of crystallized magnesium chlorid may be used4 ,dilute ,ammonia for ,washing4--,one volume of ammonia1 of #j4if specific gravity1 mixed with three volumes of water1 or usually one volume of concentrated ammonia with six volumes of water4 #bc4 ,use of ,tartaric ,acid in ,phosphoric ,acid ,estimation4--,in the presence of iron the molybdate mixture is likely to carry down some ferric oxid with the yellow precipitate4 ,to prevent this1 and also hinder the separation of molybdic acid in the solution on long standing1 tartaric acid has been recommended4 ,jptner has found that the presence of tartaric acid does not interfere with the separation of the yellow precipitate1 as some authorities assert4#ab ,even #ajj grams of the acid in one liter of molybdate solution produce no disturbing effect4 ,molybdate solution treated with tartaric acid did not show any separation of molybdic acid when kept for a year at room temperatures4 ,the presence of tartaric acid1 therefore1 is highly recommended by him to prevent the danger of obtaining both ferric oxid and molybdic acid with the yellow precipitate4 #bd4 ,water and ,organic ,matters4--,the sample1 according to the practice of ,chatard1 should be ground fine enough to leave no residue on an eighty mesh sieve1 and should be thoroughly mixed by passing it three times through a forty mesh sieve#ac4 ,two grams are weighed into a tared platinum crucible4 ,this1 with its lid1 is placed in an air-bath at #aje1 and heated for at least three hours4 ,the lid is then put on1 and the crucible is placed in a desiccator and weighed as soon as cold4 ,the loss in weight is the moisture4 ,wyatt recommends that two grams of the fine material be heated in ground watch-glasses1 the edges of which are separated so as to allow the escape of the moisture4#ad ,the heating is continued for three hours at #aaj1 the watch-glasses then closed and held by the clip1 cooled in a desiccator1 and weighed4 ,this method is excellent for very hygroscopic bodies1 but where quick-acting balances are used1 scarcely necessary for a powdered mineral4 ,the residue from the moisture determination is gradually heated to full redness over a bunsen1 and then ignited over the blast-lamp4 ,this operation is repeated after weighing until a constant weight is obtained4 ,the loss 7after deducting the percentage of carbon dioxid as found in another portion7 may be taken as water and organic matter4 ,this method is sufficient for all practical purposes2 but when minerals containing fluorin are strongly ignited1 a part of the fluorin is expelled2 hence1 if more accurate determinations are required1 the loss of fluorin must be taken into account4 ,in this laboratory it has been proved that a pure calcium fluorid undergoes progressive decomposition at a bright red heat with formation of lime4 ,wyatt directs that the combined water and organic matters be determined in the residue from the moisture estimation as follows3 ,the residue is brushed into a weighed platinum crucible1 which is heated over a small bunsen for ten minutes and then brought to full heat of a blast-lamp for five minutes4 ,after cooling1 the total loss is determined by weighing4 ,after deducting the carbon dioxid determined in a separate portion1 the residual loss is regarded as due to combined moisture and organic matter4 #be4 ,carbon ,dioxid4--,many forms of compact apparatus have been devised for this estimation1 but none of them is satisfactory if accurate results are desired4#ae ,not to mention other objections1 many phosphates must be heated nearly to the boiling-point with dilute acid to effect complete decomposition of the carbonates4 ,the distillation method described by ,gooch#af is excellent1 and when once the apparatus is set up1 its work will be found to be rapid and satisfactory4 ,wyatt regards the estimation of carbon dioxid as one of the most important for factory use4 ,the carbonates present in a sample indicate the loss of an equivalent amount of acid in the process of conversion into superphosphate4#ag ,the apparatus employed for estimating carbon dioxid may be any one of those in ordinary use for this purpose4 ,the principle of the process depends on the liberation of the gas with a mineral acid1 its proper desiccation1 and subsequent absorption by a caustic alkali1 best in solution4 ,the apparatus of ,knorr1 described in volume first1 page #cch1 may be conveniently used4 ,the weight of the sample to be used should be regulated by the content of carbonate4 ,when this is very high1 from one to two grams will be found sufficient2 when low1 a larger quantity must be used4 ,hydrochloric is preferred as the solvent acid4 ,those forms of apparatus which are weighed as a whole and the carbon dioxid determined by reweighing after its expulsion1 are not as reliable as the absorption apparatus mentioned4 #bf4 ,soluble and ,insoluble ,matter4--,five grams of the fine phosphate are put into a beaker1 twenty-five cubic centimeters of nitric acid1 7specific gravity #a4bj7 and #ab4e cubic centimeters of hydrochloric acid 7specific gravity #a4ab7 are added4 ,the beaker1 covered with a watch-glass1 is placed upon the water-bath for thirty minutes#ah4 ,the contents of the beaker are well stirred from time to time1 and at the end of the period the beaker is removed from the bath1 filled with cold water1 well stirred1 and allowed to settle4 ,the solution is next filtered into a half liter flask1 and the residue is thoroughly washed with cold water1 partially dried1 and then ignited1 7finishing with the blast-lamp7 and brought to constant weight4 ,the figures thus obtained will1 however1 be incorrect1 because the fluorin liberated during the solution of the phosphates dissolves a portion of the silica4 ,hence1 the results are too low4 ,nevertheless1 as the same action would occur in the manufacture of a superphosphate from the material1 the determination may be considered1 as a fair approximation to commercial practice4 ,the ignited residue must be tested for phosphorus pentoxid4 #bg4 ,preparation of the ,solution4--,the flask containing the filtrate is filled to the mark with cold water1 and the solution is thoroughly mixed by twice pouring into a dry beaker and returning it to the flask4 ,cold water is used for washing the residue1 since if hot water be used1 the sesquichlorids are apt to become basic and insoluble1 and hence to remain in the residue and on the filter paper4 ,besides1 as the flask is to be filled to the mark1 the contents must be cold before any volumetric measurements can be made4 #bh4 ,silica and ,insoluble ,bodies4--,wyatt describes the following method for determining the total insoluble or siliceous matters in a mineral phosphate#ai4 ,five grams of the fine sample are placed in a porcelain dish with about thirty cubic centimeters of aqua regia4 ,the dish is covered with a funnel1 placed on a sand-bath and1 after solution is complete1 evaporated to dryness with care to prevent sputtering4 ,when dry the residue is moistened with hydrochloric acid and again dried1 rubbing meanwhile to a fine powder4 ,the heat of the bath is then increased to #abe and maintained at this temperature for about ten minutes4 ,when cool1 the residue is treated with fifty cubic centimeters of hydrochloric acid for fifteen minutes4 ,the acid is then diluted and filtered on a gooch1 which is washed with hot water until the filtrate amounts to a quarter of a liter4 ,the residue in the crucible is dried1 ignited1 and weighed4 ,this method1 unless the solution be subsequently boiled with nitric acid1 may not retain all the phosphoric acid in the ortho form4 ,it is difficult to estimate the total silica by the ordinary methods of mineral analysis4 ,this is due to the fact that in an acid solution of a substance containing silicates and fluorids the whole of the silica or the fluorin1 as the case may be may escape as silicofluorid on evaporation4 ,again1 it is not easy to decompose calcium phosphate by fusing with sodium carbonate4 ,if an attempt be made to do this1 however1 the process should be conducted as follows3 ,a portion of the sample is ground to an impalpable powder in an agate mortar4 ,from one to two grams of the substance are mixed with five times its weight of sodium carbonate and fused with the precautions given in standard works on quantitative analysis4 ,the fused mass is digested in water1 boiled1 and filtered1 and the residue washed first with boiling water and afterwards with ammonium carbonate4 ,the filtrate contains all the fluorin as sodium fluorid and1 in addition to this1 sodium carbonate1 silicate1 and aluminate4 ,mix the filtrate with ammonium carbonate and heat for some time1 replacing the ammonium carbonate which evaporates4 ,separate by filtration the silicic acid hydrate and aluminum hydroxid which are formed and wash them with ammonium carbonate4 ,to separate the last portions of silica from the filtrate1 add a solution of zinc oxid in ammonia4 ,evaporate until no more ammonia escapes and separate1 by filtration1 the zinc silicate and oxid4 ,determine the silica in this precipitate by dissolving in nitric acid1 evaporating to dryness1 taking up with nitric acid and separating the undissolved silica by filtration4 ,in the alkaline filtrate the fluorin may be estimated by the usual method as calcium salt4 #bi4 ,estimation of ,lime4--,one hundred cubic centimeters of the solution 7containing one gram of the original substance7 are evaporated in a beaker to about fifty cubic centimeters2 ten cubic centimeters of dilute sulfuric acid 7one to five7 are added2 and the evaporation is continued on the water-bath until a considerable crop of crystals of gypsum has formed#bj4 ,the solution is then allowed to cool1 when it generally becomes pasty1 owing to the separation of additional gypsum4 ,when it is cold1 #aej cubic centimeters of ninety-five per cent alcohol are slowly added1 with continual stirring1 and the whole is allowed to stand for three hours1 being stirred from time to time4 ,after three hours1 it is filtered1 with the aid of a filter-pump1 into a distillation flask1 and the beautifully crystalline precipitate1 which does not adhere to the beaker1 is washed with ninety-five per cent alcohol4 ,the filter1 with the precipitate1 is gently removed from the funnel and inverted into a platinum crucible1 so that1 by squeezing the point of the filter1 the precipitate is made to fall into the crucible1 and the paper can be pressed down smoothly upon it4 ,on gentle heating of the crucible1 the remaining alcohol burns off1 and when the paper has been completely destroyed1 the heat is raised to the full power of a bunsen for about five minutes4 ,after cooling in a desiccator the crucible containing the calcium sulfate1 is weighed4 ,the filtration may also be accomplished on asbestos felt4 #cj4 ,the ,ammonium ,oxalate ,method4--,this method has been extensively used in this country in commercial work1 and is best carried out as described by ,wyatt4#ba ,the total filtrates from the iron and alumina precipitates1 secured as described in paragraph #cc1 are well mixed and concentrated to a volume of about #ajj cubic centimeters4 ,there are added about twenty cubic centimeters of a saturated solution of ammonium oxalate1 and after stirring1 the mixture is allowed to cool and remain at rest for six hours4 ,the supernatant liquid is poured through a filter1 the residue washed three times by decantation with hot water and brought upon the filter4 ,the beaker and precipitate are washed at least three times4 ,the precipitate is dried and ignited at low redness for ten minutes4 ,the temperature is then raised by a blast and the ignition continued for five minutes longer1 or until the lime is obtained as oxid4 ,the precipitate is likely to contain magnesia4 ,the magnesia is estimated in the filtrates from the lime determination by first mixing them and concentrating to #ajj cubic centimeters1 which1 after cooling1 are made strongly alkaline with ammonia4 ,after allowing to stand for twelve hours the ammonium magnesium phosphate is collected and reduced to magnesium pyrophosphate by the usual processes4 ,if one gram of the original material has been used the pyrophosphate obtained1 multiplied by #j4cf1 will give the weight of magnesia contained therein4 #ca4 ,lime ,method of ,immendorff4--,the tedious processes required to determine the lime in the presence of iron1 alumina1 and large quantities of phosphoric acid are well known to analysts4 ,immendorff has published a method1 accompanied by the necessary experimental data1 based on the comparative insolubility of calcium oxalate in very dilute solution of hydrochloric acid4 ,he has shown in the data given that the lime is all precipitated in the conditions named and that the precipitate1 when properly prepared1 is not contaminated with weighable amounts of the other substances found in the original solution#bb4 ,the ease with which oxalic acid can be determined volumetrically with potassium permanganate solution aids greatly in the time-saving advantages of the process4 ,in a hydrochloric acid solution of a mineral phosphate an aliquot part of the filtrate representing about #bej milligrams of calcium oxid1 usually about twenty-five cubic centimeters1 should be taken for the analysis4 ,ammonia is added in slight excess and then the acid reaction restored with hydrochloric until shown plainly by litmus4 ,the solution is then heated and the lime thrown down by adding a solution of ammonium oxalate in excess4 ,in order to secure a greater dilution of the hydrochloric acid after the precipitation has been made1 water should be added until the volume is half a liter4 ,before filtering1 the whole should be cooled to room temperature4 ,the precipitate should be washed first with cold and afterwards with warm water4 ,the well-washed precipitate is dissolved in hot dilute sulfuric acid and the solution1 while hot1 titrated with a standard solution of potassium permanganate set by a solution of ammonio-ferrous sulfate4 ,if one cubic centimeter of the permanganate represent #j4jje gram of iron it will correspond almost exactly to #j4jjce gram of calcium oxid4 ,example4--,sample of rather poor mineral phosphate1 five grams in half a liter4 ,strength of potassium permanganate1 one cubic centimeter equivalent to #j4jjfig gram of iron and to #j4jjcdhd gram of calcium oxid4 ,twenty-five cubic centimeters of the solution1 representing one quarter of a gram1 in which the lime was precipitated as above described1 required #i4f cubic centimeters of the potassium permanganate to saturate the oxalic acid4 ,then #i4f #j4jjcdhd #j4jccddfd gram1 or #ac4ch per cent of calcium oxid4 ,the method is also applicable to basic slags4 #cb4 ,estimation of ,iron and ,alumina in ,mineral ,phosphates4--,when mineral phosphates are to be used for the manufacture of superphosphates by treatment with sulfuric acid their content of iron and alumina becomes a matter of importance4 ,by reason of the poor drying qualities of the sulfates of these bases their presence in any considerable excess of a few per cent becomes exceedingly objectionable4 ,the accurate estimation of these ingredients is not only then a matter of scientific interest but one of great commercial significance to the manufacturer4 ,the conventional methods so long in use depending on the precipitation of the iron and alumina as phosphates in the presence of acetic acid have been proved to be somewhat unreliable4 ,not only does the acetic acid fail to prevent the precipitation of some of the lime1 but it also dissolves more or less of the iron and aluminum phosphates4 ,the solution of the precipitate and its reprecipitation by the addition of ammonia1 may free the second precipitate from lime1 but it increases the error due to the solubility of the aluminum salt4 ,the methods recently introduced for the estimation of iron and alumina in presence of excess of lime and phosphoric acid are not entirely satisfactory1 but are the best which can now be offered4 #cc4 ,the ,acetate ,method4--,the principle of this process is based on the fact that in a solution containing iron1 alumina1 lime1 and phosphoric acid the iron and aluminum phosphates can be thrown down in a slightly acid solution by ammonium acetate while the calcium phosphate remains in solution4 ,the acidity in the older methods is due to acetic and can be secured by making the solution slightly alkaline with ammonia and adding acetic to slight acidity4 ,one of the best methods of conducting the operation is that of ,c4 ,glaser#bc4 ,glaser's modification of the older processes is based on the assumption that at #gj the aluminum phosphate is quantitatively precipitated by ammonium acetate in a dilute hydrochloric acid solution and that the mixed precipitates of iron and aluminum phosphates obtained at this temperature are free of lime4 ,the operation is conducted in the following manner3 ,the hydrochloric acid solution of the phosphate must contain no free chlorin and is treated with a few drops of a methyl orange solution4 ,ammonia is added until nearly neutral1 but the acid reaction is retained as shown by the indicator4 ,a few cubic centimeters of ammonium acetate are added1 which produce a yellow coloration of the liquid and also a complete precipitation of the iron and aluminum phosphates when warmed to #gj4 ,at this temperature the precipitation of any calcium phosphate is avoided4 ,a small quantity of the lime may be carried down mechanically and therefore the precipitate should be dissolved in hydrochloric acid and the precipitation again made as above after the addition of some sodium phosphate4 ,if the original solution contain any free chlorin1 as may be the case when aqua regia is employed as solvent1 before beginning the separation1 ammonia should be added in slight excess and the acidity restored by hydrochloric after adding the indicator4 ,in washing the precipitates1 water of not over #gj must be used4 ,as has been shown by ,hess in the work cited in the next paragraph1 the statement of ,c4 ,glaser to the effect that the precipitates obtained as above are free of lime has not been proved to be strictly correct4 ,the process1 however1 is a distinct improvement over the older methods and forms the basis of the amended process given below1 which appears to be sufficiently accurate to entitle the acetate method to favorable consideration4 #cd4 ,method of ,hess4--,hess has lately made a thorough investigation of the standard methods of determining the iron and aluminum oxids in the presence of phosphoric acid and has shown that the assumption that the composition of the precipitate is represented by the formula ,al7,,po7 ,fe7,,po7 is erroneous#bd4 ,in the washing of the precipitated iron and aluminum phosphates there is a progressive decomposition of the compound with the production of a basic salt4 ,the composition of the precipitate at the end is dependent chiefly upon the way in which the washing takes place4 ,it is quite difficult to always secure a washing in exactly the same way and the final composition of the precipitate varies with almost every determination4 ,it is not1 therefore1 an accurate proceeding to take half the weight of the precipitate as phosphoric acid or as iron oxid and alumina4 ,in every case it is necessary to dissolve the precipitate and determine the phosphoric acid in the regular way4 ,hess proposes the following method for carrying out the acetate process of separation3 ,the mineral phosphate should be dissolved in hydrochloric acid and the solution made up to such a volume as shall contain in each fifty cubic centimeters1 one gram of the original substance4 ,this quantity of the solution is diluted with two or three times its volume of water to which a drop of methyl orange solution 7#a-ajj7 is added1 and ammonia added with constant stirring until the solution is just colored and still reacts slightly acid4 ,without taking any account of the precipitate which is produced by this approximate neutralization of the solution1 there are added fifty cubic centimeters of acid ammonium acetate which in one liter contains #bej grams of commercial ammonium acetate4 ,the acidity of the solution is due to an excess of acetic in the commercial salt4 ,the temperature is then carried to #gj and the precipitate produced immediately separated by filtration1 washed four times with water below #gj1 and again dissolved in dilute hydrochloric acid4 ,the dissolved precipitate is treated with ten cubic centimeters of a ten per cent ammonium phosphate solution and again almost neutralized as described above1 twenty-five cubic centimeters of the ammonium acetate solution added and warmed to #gj4 ,the precipitate obtained is once more dissolved and precipitated as above described1 and is then collected upon a filter1 washed1 ignited1 and weighed4 ,the residue after ignition is dissolved in the crucible by heating with a little concentrated hydrochloric acid1 and washed into a beaker4 ,any silicic acid present is separated by filtration1 ignited1 and weighed1 and subtracted from the total weight of the precipitate4 ,to the filtrate is added ammonia to diminish the acidity1 but not sufficient to produce a precipitate and the clear solution is treated with thirty cubic centimeters of the ordinary ammoniacal citrate solution and fifteen cubic centimeters of magnesium mixture1 and the precipitation of the ammonium magnesium phosphate hastened by stirring with a glass rod4 ,it is advisable to always make the filtrate from the third precipitation slightly ammoniacal and to boil it for a long time4 ,if the operation have been carried on correctly1 there occurs only a slight precipitate of ,ca,p,o amounting only to a few milligrams4 ,in some cases it may be necessary to dissolve the precipitate and reprecipitate the iron and aluminum phosphates a fourth time4 ,the whole time required for the triple precipitation1 according to ,hess1 if all the operations be properly conducted1 is from three to four hours4 ,it is therefore possible by this variation of the acetate method to secure a determination of the iron and alumina as phosphates in the same time which is occupied by the ,glaser-,jones method when the separation of lime is taken into account4 ,if the solution of the mineral phosphate employed contain any notable quantity of organic material1 it must be destroyed by boiling with bromin or some other oxidation agent1 before the precipitation by the acetate method is commenced4 ,the presence of silicic acid need not be taken into special consideration since this can be detected and determined in the phosphate precipitates after they have been ignited and weighed4 ,while the determinations of the phosphoric acid in ,hess' method were made by precipitation in the presence of citrate1 he found that they agree perfectly with the previous precipitations with molybdic solution4 #ce4 ,method of ,glaser4--,the principle on which this method rests depends on the preliminary removal of the lime by conversion into calcium sulfate and its precipitation in the presence of strong alcohol4#be ,it is conducted as follows3 ,five grams of the phosphate are dissolved in a mixture of twenty-five cubic centimeters of nitric acid of #a4b specific gravity and about #ab4e cubic centimeters of hydrochloric acid of #a4ab specific gravity1 and made up to a volume of half a liter1 and filtered4 ,one hundred cubic centimeters of the filtrate1 equivalent to one gram of the substance1 are placed in a quarter liter flask and twenty-five cubic centimeters of sulfuric acid of #a4hd specific gravity added4 ,the flask is allowed to stand for about five minutes and meanwhile shaken a few times4 ,about #ajj cubic centimeters of alcohol of ninety-five per cent are then added and the flask filled with alcohol to the mark and well shaken4 ,a certain degree of concentration takes place and this is compensated for by lifting the stopper and filling again with alcohol to the mark and shaking a second time4 ,after allowing to stand for half an hour the contents of the flask are filtered1 #ajj cubic centimeters of the filtrate being equal to four-tenths gram of the substance4 ,this volume1 filtered1 is evaporated in a platinum dish until the alcohol is driven off4 ,the alcohol-free residue is heated to boiling in a beaker with about fifty cubic centimeters of water4 ,ammonia is added to alkaline reaction1 but in order to avoid strong effervescence it is not added during the boiling4 ,the excess of ammonia is evaporated1 the flask allowed to cool1 the contents filtered1 precipitate and filter washed with warm water1 ignited1 and the phosphates of iron and alumina weighed4 ,half of the weight of the precipitate represents the weight of ,fe,o ,al,o4 ,the estimation1 as before indicated1 should be carried on without delay1 the whole time required not exceeding from one and a half to two hours4 #cf4 ,jones' ,variation4--,the method of ,glaser described above1 as practiced by the ,german chemists1 has been found by ,jones to be inaccurate on account of the alcohol not being added in sufficient quantity in the precipitation of calcium sulfate and for the additional reason that the amount of sulfuric acid added is more than is actually necessary#bf4 ,jones modifies the method as follows3 ,ten grams of the material are dissolved in nitro-hydrochloric acid and the solution made up to #ejj cubic centimeters and filtered4 ,fifty cubic centimeters of this solution1 representing one gram1 are evaporated to twenty-five cubic centimeters and1 while still hot1 ten cubic centimeters of dilute sulfuric acid 7one to five7 added4 ,the mixture is then well stirred and cooled4 ,one hundred and fifty cubic centimeters of ninety-five per cent alcohol are next added and after stirring1 the solution is allowed to stand three hours4 ,the calcium sulfate is collected on a filter1 washed with alcohol1 and the filtrate and washings collected in an erlenmeyer4 ,the washing is completed when the last ten drops1 after dilution with an equal volume of water1 are not colored with a drop of methyl orange4 ,the moist calcium sulfate is transferred to a platinum crucible1 the filter placed on it1 the alcohol burned off1 the filter incinerated1 and the calcium sulfate ignited and weighed4 ,the contents of the flask are heated to expel the alcohol1 the residue washed into a beaker1 made slightly alkaline with ammonia1 and again heated till all the ammonia is driven off4 ,this treatment is necessary to prevent the precipitate from being contaminated with magnesia4 ,the precipitate is collected on a filter1 washed four times with hot water1 or water containing ammonium nitrate1 dried1 ignited1 and weighed4 ,one-half of the weight of the precipitate represents the weight of the ferric and aluminic oxids4 #cg4 ,estimation of ,iron and ,alumina in ,phosphates by ,crispo's ,method4--,the phosphate of ferric iron is subject to a slight decomposition in presence of both hot and cold water with a tendency to the production of basic compounds4 ,it is soluble to a slight extent in hot and cold acetic acid1 almost insoluble in ammonium acetate1 and quite insoluble in ammonium chlorid and nitrate4 ,aluminum phosphate is likewise soluble1 to a slight degree1 in acetic acid and ammonium acetate1 and insoluble in ammonium chlorid and nitrate4 ,the method of ,crispo for the separation of iron and alumina in phosphates is based on the above properties4#bg ,five grams of the mineral phosphate are dissolved in fifty cubic centimeters of aqua regia1 composed of forty cubic centimeters of hydrochloric acid of #a4aj1 and ten of nitric acid of #a4bj specific gravity1 and this solution is diluted to half a liter4 ,to fifty cubic centimeters of the filtered solution are added two of ammonia 7#j4if7 and fifty of a half saturated solution of ammonium chlorid1 and the whole boiled4 ,the liquid should remain clear1 but if it become cloudy add a little dilute nitric acid1 drop by drop1 until the turbidity is removed1 and then ten cubic centimeters of a saturated solution of ammonium acetate1 and boil for three minutes1 cool1 and filter4 ,the precipitate is washed twice with a ten per cent solution of ammonium chlorid and redissolved with two cubic centimeters of nitric acid1 and the filter washed with hot water4 ,the phosphoric acid is separated by forty cubic centimeters of molybdate solution1 and the precipitate washed three or four times with a one per cent nitric acid solution4 ,to the filtrate are added fifty cubic centimeters of a one-half saturated ammonium chlorid solution1 ammonia is added in slight excess to produce precipitation and the mixture boiled for a few minutes4 ,after filtering1 the precipitate is washed with hot water three or four times1 dissolved in two cubic centimeters of nitric acid1 and the filter washed with hot water4 ,again1 fifty cubic centimeters of half saturated ammonium chlorid are added and the precipitate thrown down once more by ammonia in slight excess4 ,the precipitate is washed with hot water and finally ignited and weighed as iron and aluminum oxids4 ,according to ,crispo1 the original ,glaser method1 with its various modifications1 is not to be considered reliable1 and the choice lies between the molybdic method as usually practiced1 and his own for the accurate estimation of iron and alumina4 ,manganese disturbs the accuracy of the results unless the directions given are carefully followed4 ,manganese phosphate is soluble at all temperatures below fifty4 ,if then the mixture of the phosphates be allowed to cool before filtering1 the iron and aluminum salts are not contaminated with manganese4 ,this method of ,crispo is somewhat tedious1 but it is claimed that these variations of the molybdic method render it exact in respect of the determination of iron and alumina4 #ch4 ,method ,employed in ,geological ,survey4--,chatard gives the following directions for conducting the ,glaser-,jones process#bh3 ,the distillation flask containing the alcoholic filtrate is connected with its condenser and heated on a water-bath until no more alcohol comes over4 ,this distillate1 if mixed with a little sodium carbonate and redistilled over quicklime1 can be used over and over again1 so that the expense for alcohol is really very slight1 while in the use of the ,glaser method1 with its large amount of sulfuric acid1 all the alcohol is lost4 ,when the distillation is ended the residue in the flask is washed into a platinum dish and evaporated to a small bulk on the water-bath4 ,the dark brown color produced is due to the presence of organic matter and this must be destroyed1 as it prevents the complete precipitation of the phosphate in the subsequent operation4 ,the organic matter is best destroyed by removing the dish from the bath1 adding a small quantity of pure sodium nitrate1 and heating very carefully over the naked flame1 keeping the dish well covered with a watch-glass to avoid spattering4 ,the mass fuses to a colorless1 viscous liquid1 becoming glassy when cooled and is readily soluble in a hot very dilute solution of nitric acid4 ,the solution transferred to a beaker is made distinctly alkaline with ammonia and carefully neutralized with acetic acid1 diluted with hot water1 boiled1 and the precipitate allowed to settle1 after which it is separated by filtration4 ,after the precipitate has been completely transferred to the filter1 the washing is completed with a dilute solution of ammonium nitrate4 ,the precipitate is dried1 ignited1 cooled1 and weighed4 ,the determinations should be made in pairs1 one portion being used for the estimation of the phosphoric acid by fusing with a little sodium carbonate1 and the other1 after fusion with sodium carbonate1 is dissolved with sulfuric acid and the iron reduced and titrated with potassium permanganate solution4 ,the filtrate from the iron and alumina determination is evaporated to a small bulk1 made strongly ammoniacal and allowed to stand for some time when the magnesia present separates as ammonium magnesium phosphate which is determined in the usual way4 ,if1 during the evaporation of the filtrate1 any flocculent matter separate1 it should be removed by filtration and examined before precipitating the magnesia4 #ci4 ,variation of ,marioni and ,fasselli4--,glaser's method has been shown to be subject to errors by ,marioni and ,fasselli#bi in the following respects3 #a4 ,the precipitation of a small quantity of calcium phosphate with the ferric and aluminum phosphates4 #b4 ,the possible precipitation of basic phosphates if all the iron and alumina are not combined with phosphoric acid in the mineral4 #c4 ,the partial solubility of ferric and aluminum phosphates in dilute acetic acid4 #d4 ,the decomposition of ferric orthophosphate into soluble acid phosphate and insoluble basic salt by boiling4 ,to avoid these errors the following procedure is proposed3 ,from one to five grams of the phosphate are boiled in a flask for ten minutes with fifteen cubic centimeters of strong hydrochloric acid1 and afterwards diluted with a double volume of water4 ,a few crystals of potassium chlorate are added1 and several drops of nitric acid1 and the liquid boiled to expel chlorin4 ,it is then filtered and washed until the volume of the filtered liquid amounts to #aej cubic centimeters4 ,after cooling1 a half gram of ammonium phosphate in solution is added1 and two cubic centimeters of glacial acetic acid1 followed by dilute ammonia1 drop by drop1 until a slight precipitate persists on stirring4 ,again the same quantity of acetic acid is added as above1 well shaken1 and left for two hours4 ,the precipitate is collected on a filter and washed with a one per cent ammonium phosphate solution4 ,the precipitate is dissolved by a minimum quantity of hydrochloric acid and the solution collected in the same vessel in which the precipitation took place4 ,a second precipitation is conducted just as described above4 ,the precipitate is washed as above described and ignited at a dull red heat4 ,half the weight obtained represents the ferric oxid and alumina4 #dj4 ,method of ,ogilvie4--,for the separation of alumina from phosphoric acid ,ogilvie recommends that the filtrate from the phosphomolybdate precipitate be neutralized with ammonia1 the precipitate thus formed redissolved in nitric acid1 again precipitated with ammonia1 filtered1 ignited1 and weighed as aluminum oxid4#cj ,if iron be present it will1 of course1 appear in the product4 ,for use in the examination of mineral phosphates the method can not have a wide application without amendment4 #da4 ,method of ,krug and ,mc,elroy4--,krug and ,mc,elroy show that when sufficient alcohol is added to precipitate all of the calcium sulfate in the ,glaser method1 it will also cause a precipitation of a considerable quantity of iron1 by means of which the calcium sulfate will be colored4#ca ,the presence of potassium and ammonium salts also affects very notably the precipitation of calcium4 ,the method employed by them1 in order to avoid these sources of error1 is as follows3 ,one hundred cubic centimeters1 equivalent to one gram of the substance1 in a nitric acid solution1 are placed in a half liter flask and a solution of ammonium molybdate added until all the phosphoric acid has been precipitated4 ,the addition of ammonium nitrate will hasten the separation of the ammonium phosphomolybdate4 ,the liquid should be allowed to stand for twelve hours4 ,the flask is then filled to the mark1 the contents well shaken1 filtered through a dry filter1 and duplicate samples of #bjj cubic centimeters each of the filtrate taken for analysis4 ,a small quantity of ammonium nitrate is dissolved in the liquid1 and ammonia cautiously added1 keeping the solution as cool as possible4 ,the iron and alumina are precipitated as hydroxids4 ,the mixed hydroxids are collected on a filter1 washed with water1 the filtrate and washings being collected in a beaker4 ,the precipitate should be dissolved with a small quantity of a solution of ammonium nitrate and nitric acid1 again precipitated with ammonia1 filtered1 washed1 ignited1 and weighed4 ,this treatment is for the purpose of excluding all possibility of error from the presence of molybdic anhydrid4 ,after weighing1 the mixed oxids should be fused with sodium bisulfate1 the magma dissolved in water1 and the iron determined volumetrically with potassium permanganate after reduction to the ferrous state4 ,mc,elroy has further shown by experiments in this laboratory that even the molybdate method of separating the iron and alumina from phosphoric acid with the improvements as first suggested by ,krug and himself1 may not always give reliable results4#cb ,in a solution containing ferrous iron equivalent to #ef4d milligrams of ferric oxid1 were placed enough of a solution of sodium phosphate to correspond to #ajj milligrams of phosphorus pentoxid4 ,the precipitate was dissolved by adding nitric acid1 oxidized with bromin water1 and the phosphoric acid thrown out with ammonium molybdate4 ,the precipitate was washed with weak nitric acid and the combined filtrate and washings neutralized with ammonia4 ,the resultant precipitate was dissolved in a solution of ammonium nitrate and nitric acid1 filtered1 and again precipitated with ammonia4 ,in two instances the quantities of material recovered after ignition were #ef4i and #eg4c milligrams1 respectively1 instead of the theoretical amount1 viz41 #ef4d milligrams4 ,when the work was repeated after the addition of #djj milligrams of calcium oxid the weight of the precipitate recovered was #fb4c and #fc4a milligrams in duplicate determinations4 ,similar determinations were made with a known weight1 viz41 #ce4f milligrams of alumina4 ,the treatment of the mixture was precisely as indicated above for iron4 ,the quantity of alumina finally obtained was #bh4i and #bi4c milligrams1 respectively1 in duplicate determinations4 ,when the lime was added1 however1 the weights of alumina1 recovered1 fell to #ai4h and #bj4f milligrams1 respectively4 ,these results show that the molybdate method for the separation of iron and alumina in the presence of a large excess of lime and phosphoric acid is subject to widely varying results1 but that the error due to the excess of iron in the weighed product is partly corrected by the one due to deficiency of alumina4 #db4 ,method of ,wyatt4--,a method largely used in this country1 both in private laboratories and by fertilizer factories1 for determining iron and alumina1 is described by ,wyatt#cc4 ,it is claimed for this method that1 while it may not be strictly accurate1 yet it is rapid and easy1 and in the hands of trained analysts yields concordant results4 ,fifty cubic centimeters of the first solution of the sample in aqua regia1 or an amount thereof equivalent to one gram of the phosphate1 in a beaker1 are rendered alkaline by ammonia4 ,the resulting precipitate is first redissolved by hydrochloric acid1 and a slight alkalinity is again produced with ammonia4 ,fifty cubic centimeters of strong acetic acid are next added1 the mixture stirred and placed in a cool place and left until cold4 ,the precipitate is then separated by filtration and washed twice with boiling water4 ,the vessel holding the filtrate is replaced by the beaker in which the precipitation was made4 ,the precipitate is dissolved in a little fifty per cent hot hydrochloric acid and the filter washed with hot water4 ,after rendering slightly alkaline1 as in the first instance1 the treatment with acetic acid is repeated as described4 ,the precipitate is washed this time1 twice with cold water containing a little acetic acid and three times with hot water4 ,the precipitate is dried1 ignited1 and weighed as iron and aluminum phosphate4 ,half of this weight may be taken to represent the quantity of iron and aluminum oxids4 ,to separate the iron and alumina the precipitate just described is dissolved in hot hydrochloric acid1 filtered into a #ajj cubic centimeter flask1 and made up to the mark by hot wash-water4 ,the phosphoric acid is determined in one-half of the filtrate and in the remaining half the iron is reduced with zinc and determined with potassium permanganate in the usual way4 ,the phosphoric acid and iron having been thus determined the alumina is estimated by difference4 ,the chief objection to this process is in the excessive quantity of acetic acid used and the danger of solution of the precipitated phosphates caused thereby4 #dc4 ,estimation of the ,lime and ,magnesia4--,the filtrate and washings from the first precipitation1 7paragraph #da17 of iron and alumina in the method of ,krug and ,mc,elroy1 above described1 are collected and sufficient ammonium oxalate is added to precipitate the calcium4 ,the precipitated calcium is very fine and should be collected on a gooch1 under pressure4 ,the filtrate and washings from the calcium precipitate are again collected1 and a solution of sodium phosphate added to precipitate the magnesia4 ,the solution must be kept cool and slightly alkaline with ammonia during the above operations in order to prevent the separation of molybdic anhydrid4 #dd4 ,estimation of ,sulfuric ,acid4--,as a rule1 sulfates are not abundant in mineral phosphates4 ,in case the samples are pyritiferous1 however1 considerable quantities of sulfuric acid may be found after treatment with aqua regia4 ,the acid is precipitated with barium chlorid1 in the usual way1 in an aliquot portion of the filtrate first obtained4 ,the precipitate of barium sulfate is washed with hot water until clean1 dried1 ignited1 and weighed4 ,if the portion of the filtrate taken represent half a gram of the original material then the weight of barium sulfate obtained multiplied by #j4fheh will give the quantity of sulfur trioxid in one gram4 #de4 ,estimation of ,fluorin by the ,method of ,berzelius as ,modified by ,chatard4--,the method of estimating fluorin as proposed by ,berzelius1 has been found quite satisfactory in the laboratory of the ,geological ,survey1 with the modifications given below4#cd ,two grams of the phosphate are intimately mixed in a large platinum crucible with three grams of precipitated silica and twelve grams of pure sodium carbonate1 and the mixture is gradually brought to clear fusion over the blast-lamp4 ,when the fusion is complete the melt is spread over the walls of the crucible1 which is then rapidly cooled 7preferably by a blast of air74 ,if this have been properly done1 the mass separates easily from the crucible1 and the subsequent leaching is hastened4 ,the mass1 detached from the crucible1 is put into a platinum dish into which whatever remains adhering to the crucible1 or its lid1 is also washed with hot water4 ,a reasonable amount of hot water is now put into the dish1 which is covered and digested on the water-bath until the mass is thoroughly disintegrated4 ,to hasten this1 the supernatant liquid may1 after awhile1 be poured off1 the residue being washed into a small porcelain mortar1 ground up1 returned to the dish and boiled with fresh water until no hard grains are left4 ,the total liquid is then filtered1 and the residue is washed with hot water4 ,the filtrate 7which should amount to about half a liter7 is nearly neutralized with nitric acid 7methyl orange being used as indicator71 some pure sodium bicarbonate is at once added1 and the solution 7in a platinum dish1 if one large enough is at disposal1 otherwise in a beaker7 is placed on the water-bath1 when it speedily becomes turbid through separation of silica4 ,as soon as the solution is warm it is removed from the bath1 stirred1 allowed to stand for two or three hours1 and then filtered by means of the filter-pump and washed with cold water4 ,the filtrate is concentrated to about a quarter of a liter and nearly neutralized1 as before1 some sodium carbonate is added1 and the phosphoric acid is precipitated with silver nitrate in excess4 ,the precipitate is separated by filtration and washed with hot water1 and the excess of silver in the filtrate is removed with sodium chlorid4 ,the filtrate from the silver chlorid 7after addition of some sodium bicarbonate7 is evaporated to its crystallizing point1 then cooled and diluted with cold water2 still more sodium bicarbonate is added1 and the whole is allowed to stand1 when additional silica will separate1 and this is to be removed by filtration4 ,this final solution is nearly neutralized1 as before2 a little sodium carbonate solution is added2 it is heated to boiling and an excess of solution of calcium chlorid is added4 ,the precipitate of calcium fluorid and carbonate must be boiled for a few minutes1 when it can be easily filtered and washed with hot water4 ,the precipitate is then washed from the filter into a small platinum dish and evaporated to dryness1 while the filter1 after being partially dried and used to wipe off any particles of the precipitate adhering to the dish in which it was formed1 is burned1 and the ash is added to the main precipitate4 ,this1 when dry1 is ignited1 and allowed to cool2 dilute acetic acid is added in excess1 and the whole is evaporated to dryness1 being kept on the water-bath until all odor of acetic acid has disappeared4 ,the residue is then treated with hot water1 digested1 filtered on a small filter1 washed with hot water1 partially dried1 put into a crucible1 carefully ignited1 and weighed as calcium fluorid4 ,the calcium fluorid is then dissolved in sulfuric acid by gentle heating and agitation1 evaporated to dryness on a radiator1 ignited at full red heat1 and weighed as calcium sulfate4 ,from this weight the equivalent weight of calcium fluorid should be calculated1 and this should be very close to that actually found as above1 but should never exceed it4 ,the difference1 which is generally about a milligram 7sometimes more71 is due to silica precipitated with the fluorid4 ,the percentage of fluorin is1 therefore1 always calculated from the weight of the sulfate1 and not from that of the fluorid obtained4 ,the main improvements in this method are the use of sodium bicarbonate to separate the silica1 and the keeping of the earlier solutions as dilute as possible1 which can not be done1 if ammonium carbonate be used for the separation of the silica4 ,these changes make the fluorin estimation1 although still tedious1 far more rapid than before1 and the results are very satisfactory4 #df4 ,modification of ,wyatt4--,by reason of the tediousness of the method of ,chatard given above1 ,wyatt has sought to shorten the process by the following modification3#ce ,five grams of the finely ground phosphate are fused in a platinum dish with fifteen grams of the mixed carbonates of sodium and potassium and three grams of fine sand4 ,after fusing very thoroughly with a strong heat for a quarter of an hour1 the dish is removed from the fire and cooled4 ,its contents1 dissolved in hot water1 are then put into a half liter flask1 and a considerable excess of ammonium carbonate is added to the liquid4 ,all the soluble silica falls out of solution1 and the flask1 after cooling1 is made up to the mark with distilled water1 well shaken1 and then set aside for twenty-four hours to settle4 ,at the end of this time #bjj cubic centimeters are carefully decanted through a filter2 the filter is well washed1 and the filtrate1 after being nearly neutralized with hydrochloric acid1 is treated with an excess of calcium chlorid solution4 ,the precipitate1 consisting of phosphate1 fluorid1 and some calcium carbonate1 is allowed to settle1 and is then carefully washed with boiling water1 first by decantation several times1 and finally on the filter4 ,after being properly dried in the gas-oven1 calcined1 and cooled1 the residue is treated with acetic acid1 placed upon the water-bath1 and evaporated to complete dryness4 ,the calcium acetate is now well washed out by several treatments with boiling water1 and the residue is brought upon a filter1 dried1 calcined1 and weighed4 ,the weight represents the calcium phosphate and fluorid contained in two grams of the original sample2 and if the calcium phosphate in the residue be determined1 according to the usual methods1 the difference will be calcium fluorid and may be thus estimated4 ,example4--,assuming the calcined residue of calcium phosphate and fluorid in two grains of the original sample to have amounted to one and six-tenths gram and the calcium phosphate in this quantity to have been determined as #a4edj gram1 the calcium fluorid is thus proved to be #j4jfj gram1 and1 therefore1 #b3 #j4fj33ajj3 x #c per cent calcium fluorid which1 multiplied by #j4dhig1 gives #a4df per cent of fluorin4 ,the above method1 while shorter1 is not to be preferred to the ,chatard process when great accuracy is desired4 ,all the soluble silica may not fall out of the solution as ,wyatt says4 ,finally the fluorin is calculated from small differences in the weight of very heavy precipitates and all the error of the process may be found affecting the numbers for fluorin4 ,for commercial purposes1 however1 the method is to be recommended for its comparative brevity4 ,,general ,,methods ,,for ,,estimating ,,phosphoric ,,acid ,,in ,,fertilizers4 #dg4 ,preliminary ,considerations4--,the chief sources of the phosphoric acid in commercial fertilizers are the mineral phosphates and bones4 ,in respect of the analyses of mineral phosphates detailed directions have been given in the preceding pages4 ,bones are valuable for fertilizing materials1 both because of their content of phosphoric acid and of their organic nitrogen4 ,the methods of treating bones for their phosphoric acid will be found in the general methods for fertilizing materials1 and their nitrogen content can be determined by the processes to be described hereafter4 ,other fertilizing materials also contain phosphorus1 as ashes1 tankage1 oil cakes1 and other organic products4 ,in general1 the methods for determining the phosphoric acid is the same in all cases1 but the means of destroying the organic matter precedent to the analysis vary in different cases4 ,in most cases a simple ignition is sufficient1 while1 if the phosphorus be found in certain organic products1 the oxidation must be accomplished by one of the methods described in the processes adopted by the official chemists1 or by the means described in volume first1 paragraph #cgh or #chb4 ,in all cases of acid phosphates and superphosphates1 the water and ammonium citrate soluble phosphoric acid is to be determined as well as the total4 ,in basic slags the amount soluble in ammonium citrate or dilute citric acid is also to be ascertained4 ,in all cases where soluble or so-called reverted acid is to be considered1 the analysis must be performed without previous desiccation or ignition4 ,if water content or loss on ignition are to be considered1 the operation to determine them must be conducted on a separate part of the sample4 ,the methods of analysis which have been adopted by associations of chemists should be given the preference in the conduct of the work1 although it must be admitted that they may contain sources of error1 and may be in no respect superior to processes employed by chemists in their private capacity4 ,in this country the methods adopted by the ,association of ,official ,agricultural ,chemists should be followed as closely as possible4 ,the great merit of other methods1 however1 must not be denied4 ,especially those methods which shorten the time required or diminish the labor and expense of the analysis are worthy of careful consideration4 ,in factory work1 for instance1 it is often far more important for the chemist to be able to rapidly determine the phosphoric acid in a great number of samples with approximate accuracy than to confine his work to one with absolute precision4 ,some of the shorter methods1 moreover1 notably the citrate process1 appear to be quite1 if not altogether1 as reliable as the molybdate method1 while in the case of the uranium volumetric process1 it must not be forgotten that it is almost the only one practiced in ,france4 ,other volumetric processes are given in full1 as1 for instance1 the one perfected by ,pemberton1 but data are still lacking to justify their strong recommendation4 ,it should be remembered that this manual is not written for the beginner but rather for the chemist already acquainted with the principles and practice of general chemical analysis1 and it is1 therefore1 expected that each analyst will make intelligent use of the data placed at his disposal4 #dh4 ,determination of ,phosphoric ,acid with ,preliminary ,precipitation as ,stannic ,phosphate4--,this method1 once much in use and highly recommended1 is now almost unknown among the processes of fertilizer control4 ,it was first proposed and described by ,girard1 and rests on the precipitation of the phosphoric acid in a nitric acid solution by means of metallic tin4#cf ,the stannic acid formed by the oxidation of the tin unites with the phosphoric acid held in a free state by the nitric acid4 ,the precipitation of the phosphoric acid is said to be complete1 but a trace of it has been found in the iron and alumina subsequently separated from the solution4 ,the precipitate obtained is dissolved in caustic potash1 whereby soluble potassium metastannate and phosphate are obtained4 ,following is the method of conducting the analysis as described by ,crookes3#cg ,the phosphate should be dissolved in nitric acid1 and any chlorin present be expelled by repeated evaporations with the solvent4 ,finally1 to the evaporated mass the strongest nitric acid is added4 ,pure tin-foil is added and heat applied4 ,the phosphoric acid is precipitated by the stannic acid formed4 ,the quantity of tin used should be from six to eight times as great as that of the phosphoric acid present4 ,the precipitate is collected on a filter1 washed1 and dissolved in caustic potash4 ,the solution is saturated with hydrogen sulfid1 and on adding acetic acid in slight excess the tin sulfid is separated and removed by filtration4 ,the whole of the phosphoric acid1 supposed to be almost free of tin1 is now found in the filtrate4 ,the filtrate is concentrated to small bulk and any tin sulfid present separated by filtering1 and the phosphoric acid finally removed from the ammoniacal filtrate by precipitation with magnesia mixture4 ,the chief difficulties of this method are to be found1 on the one hand1 in the retention of some of the phosphoric acid by the iron and alumina which may be present1 and on the other1 in the presence of some tin in the final magnesium pyrophosphate4 ,if the tin be all removed as sulfid1 the latter source of error will be avoided4 ,it is difficult to secure pure metallic tin1 and this is another disturbing element in the process4 ,it can not be recommended for the work which agricultural analysts are usually called on to perform4#ch #di4 ,water-,soluble ,phosphoric ,acid4--,the method of procedure recommended by the ,association of ,official ,chemists is as follows3#ci ,place two grams of the sample in a nine centimeter filter2 wash with successive small portions of cold water1 allowing each portion to pass through before adding more1 until the filtrate measures about #bej cubic centimeters4 ,if the filtrate be turbid1 add a little nitric acid4 ,make up to any convenient definite volume2 mix well2 take any convenient portion and proceed as under total phosphoric acid4 #ej4 ,citrate-,insoluble ,phosphoric ,acid4--,heat #ajj cubic centimeters of strictly neutral ammonium citrate solution of #a4ji specific gravity to #fe in a flask placed in a bath of warm water1 keeping the flask loosely stoppered to prevent evaporation4 ,when the citrate solution in the flask has reached #fe1 drop into it the filter containing the washed residue from the water-soluble phosphoric acid determination1 close tightly with a smooth rubber stopper1 and shake violently until the filter paper is reduced to a pulp4 ,place the flask back into the bath and maintain the water in the bath at such a temperature that the contents of the flask will stand at exactly #fe4 ,shake the flask every five minutes4 ,at the expiration of exactly thirty minutes from the time the filter and residue were introduced1 remove the flask from the bath and immediately filter as rapidly as possible4 ,it has been shown by ,sanborn1 in this laboratory1 that the filtration is greatly facilitated by adding asbestos pulp4 ,wash thoroughly with water at #fe4 ,transfer the filter and its contents to a crucible1 ignite until all organic matter is destroyed1 add from ten to fifteen cubic centimeters of strong hydrochloric acid1 and digest until all phosphate is dissolved2 or return the filter with contents to the digestion flask1 add from thirty to thirty-five cubic centimeters of strong nitric1 and from five to ten cubic centimeters of strong hydrochloric acid1 and boil until all the phosphate is dissolved4 ,dilute the solution to #bjj cubic centimeters4 ,if desired1 the filter and its contents can be treated according to methods 7#a71 7#b71 or 7#c71 under total phosphoric acid4 ,mix well2 filter through a dry filter2 take a definite portion of the filtrate and proceed as under total phosphoric acid4 ,in case a determination of citrate-insoluble phosphoric acid be required in non-acidulated goods it is to be made by treating two grams of the phosphatic material1 without previous washing with water1 precisely in the way above described1 except that in case the substance contain much animal matter 7bone1 fish1 etc471 the residue insoluble in ammonium citrate is to be treated by one of the processes described below under total phosphoric acid1 7#a71 7#b71 or 7#c74 #ea4 ,total ,phosphoric ,acid4--,in case of ignition the residual material is to be dissolved in hydrochloric acid4 ,the following methods of treating the raw material1 using two grams in each case1 may be employed3 7#a7 ,evaporate with five cubic centimeters of magnesium nitrate1 ignite1 and dissolve in hydrochloric acid4 7#b7 ,boil in a ,kjeldahl flask graduated to #bej cubic centimeters1 with from twenty to thirty cubic centimeters of strong sulfuric acid1 adding from two to four grams of sodium or potassium nitrate at the beginning of the digestion and a small quantity after the solution has become nearly colorless2 or adding the nitrate in small portions from time to time4 ,after the solution is colorless1 add #aej cubic centimeters of water and boil for a few minutes1 cool1 and make up to volume4 7#c7 ,digest with strong sulfuric acid and such other reagents as are used in either the plain or modified ,kjeldahl or ,gunning methods for estimating nitrogen4 ,do not add any potassium permanganate1 but after the solution has become colorless add about #ajj cubic centimeters of water and boil for a few minutes1 cool1 and make up to a convenient volume2 two and five-tenths grams of substance and a digestion flask graduated to #bej cubic centimeters are recommended4 ,this method will be found convenient when both the nitrogen and the total phosphoric acid are to be determined in a fertilizer4 ,in this case1 after diluting the volume and mixing1 a part for the estimation of nitrogen1 may be removed with a pipette and the remainder then filtered through a dry filter and a portion taken for the determination of the total phosphoric acid4 7#d7 ,dissolve in thirty cubic centimeters of concentrated nitric acid and a small quantity of hydrochloric acid4 7#e7 ,add thirty cubic centimeters of concentrated hydrochloric acid1 heat1 and add cautiously1 in small quantities at a time1 about five-tenths gram of finely-pulverized potassium chlorate4 7#f7 ,dissolve in from fifteen to thirty cubic centimeters of strong hydrochloric and from three to ten cubic centimeters of nitric acid4 ,this method is recommended for fertilizers containing much iron or aluminum phosphate4 ,boil until all phosphates are dissolved and all organic matter is destroyed2 cool and dilute to #bjj or #bej cubic centimeters2 mix and pass through a dry filter2 take an aliquot part of the filtrate corresponding to a quarter1 half1 or one gram1 neutralize with ammonia1 and clear with a few drops of nitric acid4 ,in case hydrochloric or sulfuric acid have been used as a solvent1 add about fifteen grams of dry ammonium nitrate4 ,to the hot solutions1 for every decigram of phosphorus pentoxid that is present1 add fifty cubic centimeters of molybdic solution4 ,digest at about #fe for an hour1 filter1 and wash with water or ammonium nitrate solution4 ,test the filtrate by renewed digestion and the addition of more molybdic solution4 ,dissolve the precipitate on the filter with ammonia and hot water and wash into a beaker to a bulk of not more than #ajj cubic centimeters4 ,nearly neutralize with hydrochloric acid1 cool1 and add magnesia mixture from a burette2 add slowly 7about one drop per second71 stirring vigorously4 ,after fifteen minutes add thirty cubic centimeters of ammonia solution of #j4ie density4 ,let stand for some time2 two hours are usually enough4 ,filter1 wash with dilute ammonia1 ignite gently at first and then at white heat for ten minutes1 and weigh4 ,for the quantity of magnesia mixture to be added see paragraph #ba4 #eb4 ,citrate-,soluble ,phosphoric ,acid4--,the sum of the water-soluble and citrate-insoluble subtracted from the total gives the citrate-soluble phosphoric acid4 #ec4 ,preparation of ,reagents4--7#a7 ,ammonium ,citrate ,solution4--7a7 ,mix #cgj grams of commercial citric acid with #a1ejj cubic centimeters of water1 nearly neutralize with commercial ammonia1 cool1 add ammonia until exactly neutral 7testing with saturated alcoholic solution of corallin7 and bring to a volume of two liters4 ,test the specific gravity1 which should be #a4ji at #bj1 before using4 7b7 ,alternate ,method4--,to #cgj grams of commercial citric acid add commercial ammonia1 of #j4if specific gravity1 until nearly neutral2 reduce the specific gravity to nearly #a4ji and proceed as follows3 ,prepare a solution of fused calcium chlorid #bjj grams to the liter1 and add four volumes of strong alcohol4 ,make the mixture exactly neutral1 using a small amount of freshly prepared corallin solution as a preliminary indicator1 and test finally by withdrawing a portion1 diluting with an equal volume of water1 and testing with cochineal solution4 ,fifty cubic centimeters of this solution will precipitate the citric acid from ten cubic centimeters of the citrate solution4 ,to ten cubic centimeters of the nearly neutral citrate solution add fifty cubic centimeters of the alcoholic calcium chlorid solution1 stir well1 filter at once through a folded filter1 dilute with an equal volume of water1 and test the reaction with neutral solution of cochineal4 ,if acid or alkaline1 add ammonia or citric acid1 as the case may be1 to the citrate solution1 mix1 and test again as before4 ,repeat this process until a neutral reaction of the citrate solution is obtained4 ,at the end the specific gravity must be #a4ji at #bj4 7#b7 ,molybdic ,solution4--,see paragraph #bb4 7#c7 ,ammonium ,nitrate ,solution4--,dissolve #bjj grams of commercial ammonium nitrate in water and bring to a volume of two liters4 7#d7 ,magnesia ,mixture4--,see paragraph #bb4 7#e7 ,dilute ,ammonia for ,washing4--,see paragraph #bb4 7#f7 ,magnesium ,nitrate4--,dissolve #cbj grams of calcined magnesia in nitric acid1 avoiding an excess of the latter2 then add a little calcined magnesia in excess1 boil1 filter from the excess of magnesia1 ferric oxid1 etc41 and bring to volume of two liters4 #ed4 ,official ,methods with ,norwegian ,fertilizers4--,the ,director of the ,chemical ,control ,station of ,norway1 expresses the opinion1 that for ,norwegian1 ,swedish1 ,danish1 and ,german conditions1 the ,american methods for the determination of phosphoric acid1 notwithstanding their analytical exactness1 are quite inapplicable4#dj ,in those countries are found many1 in part1 poorly pulverized and badly mixed manures1 such as ammonium superphosphate1 potassium superphosphate1 and potassium ammonium superphosphate1 and these can not usually be so well pulverized and mixed that one can take out a true average sample of from two to two and five-tenths grams4 ,care in the analysis is useless when the material employed does not represent the average condition of the materials investigated4 ,therefore1 in the countries named1 often from ten to twenty grams1 and almost never less than five grams of substance are taken in the preparation of the solutions1 except for instance1 in the determination of nitrogen and reverted phosphoric acid4 #ee4 ,the ,molybdic ,acid ,method1 as ,practiced by ,direction of the ,union of the ,german ,experiment ,stations4--,the method adopted by the ,german ,experiment ,stations is essentially that used at ,halle4#da ,the samples are brought into solution in the following way3 ,for the estimation of phosphoric acid in bone-meal1 fish-guano and raw phosphates1 and the total phosphoric acid in superphosphates1 five grams of the sample are dissolved in fifty cubic centimeters of aqua regia1 made of three parts of hydrochloric acid of #a4ab specific gravity and one part of nitric acid of #a4be specific gravity1 or the solution may be made of a mixture of twenty cubic centimeters of nitric acid of #a4db specific gravity and fifty cubic centimeters of sulfuric acid of #a4h specific gravity4 ,the boiling should continue for half an hour4 ,the solution is made up to half a liter and filtered4 ,fifty cubic centimeters of the filtrate containing the phosphoric acid1 with double superphosphates twenty-five cubic centimeters1 are digested with #bjj cubic centimeters of ammonium molybdate solution for three hours at #ej in a water-bath and1 after cooling1 filtered1 so that as little as possible of the precipitate is collected upon the filter1 which is made of strong paper4 ,the yellow precipitate is washed by decantation in the flask nine times with twenty cubic centimeters of molybdic solution diluted with one volume of water and the filter washed out once with the same quantity of liquid4 ,the funnel1 with the filter1 is immediately placed upon the flask and the portion of the precipitate collected in the filter dissolved in five per cent ammonia1 which is easily accomplished by throwing ammonia upon it from a wash-bottle4 ,afterwards the filter is washed with a sufficient quantity of hot water and finally removed4 ,the contents of the flask are neutralized warm1 with hydrochloric acid1 the acid being added until the precipitate first formed1 after continued shaking1 is again dissolved in the liquid4 ,the solution is then cooled and treated1 drop by drop1 with constant stirring1 with twenty cubic centimeters of magnesia mixture4 ,finally twenty-five cubic centimeters of dilute ammonia solution are added1 the precipitate is not shaken1 and1 after two hours1 is filtered through a gooch4 ,for the filtering of the ammonium magnesium phosphate by the molybdic method1 freshly prepared felts are always employed since the remarkably fine crystalline precipitates will pass through a filter which has once been used4 ,it is necessary also that special precautions be taken in the ignition4 ,the crucible should be heated in a platinum cap1 which has the purpose of protecting the contents of the crucible from the access of reducing gases during the ignition4 ,after redness has been reached the cap can be removed and the crucible transferred to a blast where it is strongly ignited for ten minutes before weighing4 ,the precipitate should be pure white4 ,the molybdic solution is prepared as follows3 #aej grams of ammonium molybdate are dissolved in a liter of water1 and after the solution is completely cooled1 poured into a liter of nitric acid of #a4b specific gravity4 #ef4 ,estimation of ,soluble ,phosphoric ,acid4--#a4 ,the extraction of the superphosphates is made as follows3 ,twenty grams of the superphosphates are placed in a liter flask with #hjj cubic centimeters of water and shaken continuously for thirty minutes4 ,the flask is then filled with water to the mark and the whole again thoroughly shaken and filtered4 ,for shaking1 a machine is recommended1 driven by hand or water power4 ,the normal rate of the machine is fixed at #aej turns per minute4 #b4 ,the solution of the total superphosphates1 obtained as above1 must be boiled with nitric acid before the precipitation of the phosphoric acid in order to convert any phosphoric acid present as pyrophosphoric into tribasic phosphoric acid4 ,for each twenty-five cubic centimeters of the superphosphate solution ten cubic centimeters of concentrated nitric acid are added and the mixture boiled4 #c4 ,the precipitation of the phosphoric acid is conducted by the molybdenum method as usually practiced4 #d4 ,for the estimation of iron and alumina in each of the superphosphates the ,glaser method is recommended provisionally4 #eg4 ,methods for ,phosphoric ,acid used in the ,norway ,stations4#db--a4 ,description of the ,method for ,total ,phosphoric ,acid4--,for determining the phosphoric acid in bone-meal1 fish-guano1 and superphosphates1 five grams of the substance1 with twenty cubic centimeters of nitric acid of #a4db specific gravity1 and fifty cubic centimeters of sulfuric acid of #a4h specific gravity1 are boiled half an hour in a half liter flask1 diluted with water1 and after cooling1 made up to the mark4 ,fifty cubic centimeters of the filtrate are made alkaline with ammonia1 then acid with nitric acid1 precipitated with fifty cubic centimeters of molybdic solution for every one-tenth gram of phosphorus pentoxid present1 heated over the water-bath for one hour1 and allowed to stand twelve hours more1 when the supernatant liquid is separated by decantation the precipitate washed thoroughly with dilute molybdate solution 7#a3 #d7 dissolved in warm dilute ammonia1 and the filter washed with hot water4 ,the ammoniacal solution is neutralized with hydrochloric acid1 cooled1 mixed1 drop by drop1 with constant stirring1 with from ten to twenty cubic centimeters of magnesia mixture1 and after a quarter of an hour one-third the volume of ten per cent ammonia is added4 ,this is allowed to stand two hours1 is filtered1 washed with five per cent of ammonia until the disappearance of the chlorin reaction1 dried1 burned in an open crucible over a bunsen1 and finally for a quarter of an hour1 in a covered crucible heated over the blast4 #b4 ,water-,soluble ,phosphoric ,acid4--,to twenty grams of the substance in a liter flask1 are added #hjj cubic centimeters of water1 and shaken every fifteen minutes for two hours2 the volume made up to the mark and the phosphoric acid in fifty cubic centimeters of the filtrate1 equaling one gram substance1 is determined as under total4 #c4 ,reverted ,citrate-,soluble ,phosphoric ,acid4--,two and five-tenths grams substance are rubbed up with water1 then washed upon the filter with about #ajj cubic centimeters of water1 the residue on the filter washed into a flask with a part of the measured citrate solution1 and digested one hour at #ce to #dj with #bjj cubic centimeters of ,petermann's citrate solution4 ,the water and citrate extracts are made up to a quarter of a liter each1 and the phosphoric acid determined in from twenty-five to fifty cubic centimeters1 according to the quantity present4 ,solutions4 #a4 ,molybdate ,solution4--#cge grams of ammonium molybdate are dissolved in two and five-tenths liters of water1 and the solution poured into two and five-tenths liters of nitric acid of #a4bj specific gravity4 #b4 ,magnesia ,mixture4--#bge grams of crystallized magnesium chlorid and #cej grams of ammonium chlorid are dissolved in #cbej cubic centimeters of water and filled up to five liters with ammonia of #j4if specific gravity4 #c4 ,petermann's ,solution4--,one kilogram of citric acid is dissolved in about two liters of water and #acej cubic centimeters of ammonia of #j4ibe specific gravity and filled up with water to #egej cubic centimeters4 ,the solution then has a specific gravity of #a4ji2 #cjj cubic centimeters of ammonia of #j4ibe specific gravity are now added4 #eh4 ,swedish ,official ,method for ,determination of ,phosphoric ,acid4#dc--,the ,swedish chemists determine phosphoric acid in fertilizers both by the molybdate and the citrate methods4 ,these methods carefully conducted according to the directions given below1 give very concordant results4 ,in doubtful cases the former method is taken as the deciding one1 it having proved by long practice to give very satisfactory results4 ,reagents for the ,molybdate ,method4--#a4 ,molybdic ,solution4--,prepared by dissolving #ajj grams of finely powdered molybdic acid with heat1 in #djj grams of eight per cent ammonia of #j4ifg specific gravity and pouring the solution into #a1ejj grams of nitric acid of one and two-tenths specific gravity2 or else by dissolving #aej grams ammonium molybdate in one liter of hot water1 and pouring the solution into one liter of nitric acid of #a4b specific gravity4 ,prepared in this way1 the molybdic solution will contain1 in the former case five per cent1 in the latter case from five to six per cent of molybdic acid1 and #ajj cubic centimeters of it are required for precipitating one-tenth gram of phosphorus pentoxid4 #b4 ,magnesia ,mixture4--,prepared from #aaj grams of crystallized magnesium chlorid1 #adj grams ammonium chlorid1 #gjj grams of eight per cent ammonia of #j4ifg specific gravity and #a1cjj grams of distilled water4 ,the mixture is filtered after a few days1 if necessary2 ten cubic centimeters of the same are required for precipitating one-tenth gram of phosphorus pentoxid4 #c4 ,ten per cent ammonia of #j4iei specific gravity4 7a7 ,water-,soluble ,phosphoric ,acid4--#a4 ,preparation of the ,aqueous ,solution4--,of superphosphates and in general fertilizers containing water-soluble phosphoric acid1 a sample of twenty grams is taken1 and water poured over it in a mortar2 lumps are crushed lightly1 but completely with the pestle without pulverizing it finer2 the whole mass is then washed into a graduated flask holding one liter1 which at once is filled up to the mark4 ,the volume taken up by the residue insoluble in water1 is left out of consideration in the calculation4 ,the sample is left standing in the flask 7which is occasionally shaken7 at the ordinary temperature of the room for two hours1 and the solution is then filtered4 #b4 ,the ,determination4--,take twenty-five cubic centimeters of the superphosphate solution thus prepared 7when a twenty per cent sample is taken equal to one-tenth gram phosphorus pentoxid72 add a quantity of molybdic solution sufficient for complete precipitation1 leave standing for four hours in a beaker covered with a watch-glass2 decant the solution through a small filter1 wash the precipitate first by decantation1 then on filter1 with a mixture containing #ajj parts molybdic solution1 twenty parts nitric acid of #a4b specific gravity1 and eighty parts water1 until a few drops put into alcohol1 to which some dilute sulfuric acid has been added1 does not1 any longer1 cause turbidity4 ,the molybdic precipitate is now washed with but little water from the filter into a beaker1 and particles adhering to the filter are dissolved by a hot mixture of one part ammonia and three parts water1 which is allowed to flow into the beaker till the precipitate is1 finally1 completely dissolved in it4 ,to the clear solution1 add dilute hydrochloric acid while stirring1 till the yellow precipitate formed by the acid is no longer immediately dissolved2 then add from six to eight cubic centimeters of ammonia through the filter4 ,the volume of the solution is not to exceed seventy-five cubic centimeters4 ,it is now cooled completely and one cubic centimeter of magnesia mixture is added from a burette for every centigram of phosphorus pentoxid which it is expected to contain1 and finally one-quarter of its volume of ammonia is added4 ,the precipitate may be filtered after four hours4 ,this is washed on the filter1 preferably by means of suction1 with a mixture of one part ammonia and three parts water till the filtrate is entirely free from chlorin4 ,after drying1 heat the precipitate1 first gently1 then stronger1 and finally with a blast for a few minutes and then weigh it4 ,treated with hydrochloric acid it must leave no insoluble residue 7,si,o71 nor should hydrogen sulfid cause any precipitation in the solution thus formed 7,mo,o74 7b7 ,total ,phosphoric ,acid4--#a4 ,in ,superphosphates4--,for the determination of total phosphoric acid1 treat a weighed quantity of the superphosphate with nitric acid1 if necessary to bring a difficultly soluble residue into solution1 with addition of hydrochloric acid1 or of potassium chlorate1 to destroy organic matter present4 ,dilute the solution to a definite volume1 and determine the phosphoric acid in a measured quantity of the same1 as directed under 7a7 #b2 if hydrochloric acid or potassium chlorate1 be applied in the preparation of the solution1 however1 not till the measured quantity has been repeatedly evaporated to dryness with concentrated nitric acid4 #b4 ,in ,bone-meal4--,destroy organic matter in five grams of the sample by ignition1 dissolve the residue in nitric acid1 filter from the insoluble residue1 dilute the filtrate to half a liter1 take an aliquot part containing about one-tenth gram phosphorus pentoxid and determine the phosphoric acid as directed under 7a7 #b4 #c4 ,in ,fish-guano 7and other fertilizing materials of organic origin74--,the organic matter cannot here be removed by simple ignition1 as in this way a loss of phosphorus may take place2 ,it is therefore destroyed either in the wet way through nitric acid and potassium chlorate or in the dry way by fusion with a mixture of potassium nitrate and sodium carbonate1 otherwise the procedure is as in 7b7 #a4 #d4 ,in ,mineral ,phosphates4--,determine the phosphoric acid in a solution obtained by nitric acid2 organic matter is destroyed preferably in the wet way4 #e4 ,in ,basic ,slag4--,dissolve ten grams of powdered slag by treating it with #ajj cubic centimeters of fuming hydrochloric acid with heat2 wash the solution into a graduated half liter flask1 fill to the mark1 shake well1 and filter4 ,determine the phosphoric acid in twenty-five cubic centimeters of the clear filtrate1 according to 7a7 #b1 after having first1 however1 evaporated the solution to dryness and then at least three times evaporated the residue to dryness with concentrated nitric acid4 #ei4 ,method ,employed by the ,royal ,experiment ,station of ,holland4--,a4 ,soluble ,phosphoric ,acid4#dd--,the necessary reagents are3 7#a7 ,molybdate solution1 made by dissolving #aej grams of ammonium molybdate in a liter of water and pouring the solution into a liter of nitric acid of #a4bj specific gravity4 7#b7 ,a ten per cent solution of ammonium nitrate4 7#c7 ,strong and dilute ammonia1 the latter being between two and five-tenths and three per cent of #j4ihh specific gravity4 7#d7 ,magnesia mixture made by dissolving #aaj grams of crystallized magnesium chlorid1 #adj grams of ammonium chlorid1 and #gjj cubic centimeters of ammonia of #j4if specific gravity in water and bringing the solution to two liters4 7#e7 ,ammoniacal citrate solution1 made by dissolving #ejj grams of citric acid in a liter of water1 and mixing with four liters of ten per cent ammonia of #j4if specific gravity4 ,manipulation4--,place twenty grams of substance in a mortar together with some cold distilled water or pure rain water1 stir1 and decant the water and suspended matters into a liter flask4 ,after this has been repeated several times1 rub up the residual mass and wash it all into the flask4 ,fill up to about #ijj cubic centimeters and allow to stand two hours 7twenty-four hours in the case of double phosphates with more than twenty-two per cent of soluble phosphoric acid71 shaking repeatedly2 or shaking continuously1 for half an hour4 ,fill up to the liter mark and filter through a dry filter4 ,take portions of twenty-five or fifty cubic centimeters for each determination1 add #ajj cubic centimeters of molybdate solution for each #ajj milligrams of phosphorus pentoxid present1 warm to about #hj for an hour1 filter1 and wash the precipitate with the ammonium nitrate solution4 ,add a little molybdate solution to the filtrate1 warm1 and1 if a fresh precipitate be observed1 it is to be added to the first4 ,the precipitate is to be dissolved in ammonia1 and hydrochloric acid carefully added until the precipitate caused by it only slowly redissolves on stirring4 ,the phosphoric acid is precipitated from the clear liquid which is still ammoniacal with magnesia mixture1 using ten cubic centimeters for each #ajj milligrams of phosphorus pentoxid present4 ,this is added1 drop by drop1 and the liquid kept stirred during the addition4 ,allow it to stand at least two hours1 filter1 wash with dilute ammonia1 dry1 and ignite4 ,this last is done at first with a very small flame but is finished with the blast-lamp or in a ,rssler furnace4 ,to insure burning to whiteness1 nitric acid may be used1 but not more than one or two drops4 ,b4 ,total ,phosphoric ,acid4--7#a7 ,for bone and flesh-meal1 fish-guano1 and similar fertilizers the reagents necessary are the same as before4 ,carefully burn five grams to ash1 boil the ash for half an hour with nitric acid of #a4cb specific gravity1 dilute with water1 and1 after cooling1 dilute to #ejj cubic centimeters4 ,filter through a dry filter and take fifty cubic centimeters of the filtrate4 ,add #ajj cubic centimeters of the molybdate solution for each #ajj milligrams of phosphorus pentoxid present4 ,treat further as before described4 7#b7 ,phosphates1 guanos1 bone-black1 etc4 ,one gram of substance1 after powdering1 and1 if necessary1 igniting1 is covered with four cubic centimeters of hydrochloric acid of #a4ac specific gravity and a little water and heated for an hour and a half4 ,evaporate to dryness without filtration1 making repeated additions of nitric acid until no more vapors of hydrochloric acid are evolved4 ,boil the residue with nitric acid1 cool1 make up to #ajj cubic centimeters with water1 and shake4 ,filter and treat fifty cubic centimeters of the resulting solution by the molybdate method and proceed further as before described4 #fj4 ,sources of ,error in the ,molybdate ,method4--,when conducted with proper care1 the gravimetric molybdate method is one of the most exact processes known to analytical chemistry4 ,there are1 however1 some sources of error in the process which should be avoided as carefully as possible or taken into account4 #a4 ,error ,due to ,occluded ,silica4--,when silica passes into solution in the original sample1 and this may be the case especially with mineral phosphates1 it may appear both in the yellow precipitate and in the final magnesium pyrophosphate4 ,in all such cases the residue1 after ignition1 should be dissolved in hydrochloric acid1 and any insoluble residue weighed as silica and deducted from the first weight4 ,if the silica be removed by evaporating the solution of the original material to dryness1 and igniting to destroy organic matter1 care must be taken to reconvert all phosphoric acid into the ortho form by long boiling with nitric acid before precipitation4 ,another method of avoiding any trouble from silica consists in using sulfuric and a little nitric acid as the solvent for the original substance4 ,silica is not soluble in hot concentrated sulfuric acid4 ,the volume of the sulfuric should be about ten times that of the nitric acid used1 and the boiling be continued until sulfuric vapors are evolved4 #b4 ,error ,due to ,arsenic4--,only in rare cases will arsenic be found in phosphatic fertilizing materials4 ,in case of pyritic phosphates1 the iron disulfid may carry arsenic4 ,the solution in such a case is best accomplished in hydrochloric acid4 ,if aqua regia be used1 all nitric acid should be removed by repeated evaporation with hydrochloric4 ,the arsenic can then be precipitated in the hot dilute hydrochloric acid solution by hydrogen sulfid4 #c4 ,error ,due to ,occluded ,magnesia4--,the danger of contamination of the yellow precipitate with magnesium oxid has been pointed out by some authors4 ,the re-solution of the precipitate followed by a second precipitation is the usual remedy proposed4 ,lorenz states that this source of error may be entirely avoided by the addition of two per cent of citric acid to the phosphomolybdate solution4#de #d4 ,error ,due to ,volatility of ,phosphoric ,acid4--,this source of error has been made the subject of a special study by ,neubauer4#df ,from the results1 a table has been constructed1 the use of which is recommended for phosphoric acid determinations4 ,the source of error in this method lies exclusively in the loss of phosphoric acid by volatilization4 ,the magnesia-covered crucible lid offers a very good control of this error1 and its use is recommended to the analyst4 ,of course1 the presence of sulfur in the gas used for ignition is liable to disturb this check4 ,the following course of procedure in the determination of phosphoric acid can be recommended to avoid or correct this error3 ,separate the phosphoric acid in the form of the yellow precipitate and wash this latter in the usual way4 ,too high a heat should not be employed1 nor should the solutions be allowed to stand too long lest excess of molybdic acid separate4 ,dissolve the phosphomolybdate in #ajj cubic centimeters of cold two and five-tenths per cent ammonia and add as many cubic centimeters of the usual magnesia mixture 7fifty-five grams magnesium chlorid and seventy grams ammonium chlorid dissolved in a liter of two and five-tenths per cent ammonia7 as there are centigrams of phosphorus pentoxid present4 ,addition should not be made faster than ten cubic centimeters per minute4 ,stir during the addition4 ,after the precipitation1 stir briskly once more and then allow to stand at least three hours4 ,wash with two and five-tenths per cent ammonia till the chlorin reaction disappears1 dry the filter1 and introduce into a well-cleaned crucible which has been thoroughly ignited4 ,place the lid at an angle1 carbonize the filter1 and gradually raise the heat1 though not higher than a medium red heat1 till the pyrophosphate becomes completely white4 ,when this happens bring the blast into action and ignite to constant weight4 ,the weight finally accepted must not change even after half an hour's ignition4 ,upon this requirement especial stress must be laid4 ,pure magnesium pyrophosphate does not suffer any loss even after several hours' ignition nor does a good platinum crucible4 ,to the weighed amount of pyrophosphate1 add the correction given in the table4 ,for example1 if the weight be #bej milligrams1 the correction to be added is four and two-tenths milligrams1 and the correct weight is then #bed4b milligrams4 ,multiplication of the sum by sixty-four gives the amount of phosphorus pentoxid in the weight taken for analysis4 ,,correction ,,for ,,phosphoric ,,acid ,,determination4 ,found1 ,lost1 ,found1 ,lost1 ,mg,p,o milligrams ,mg,p,o milligrams in grams4 ,mg,p,o4 in grams4 ,mg,p,o4 #j4aj #j4f #j4bd #d4j #j4ab #j4h #j4be #d4b #j4ad #a4b #j4bf #d4f #j4ae #a4d #j4bg #e4j #j4af #a4f #j4bh #e4e #j4ag #b4d #j4bi #f4a #j4ah #b4f #j4cj #f4h #j4ai #c4b #j4ca #g4f #j4bj #c4e #j4cb #h4f #j4ba #c4f #j4cc #i4f #j4bb #c4h #j4cd #aj4f ,when phosphoric acid is to be estimated as pyrophosphate it must always be first separated as molybdate1 even when the original solution contains no bases capable of forming insoluble phosphates1 as otherwise these corrections will not be applicable4 ,using these corrections the estimation of phosphoric acid becomes one of the most accurate of known analytical methods4 #fa4 ,the ,color of the ,magnesium ,pyrophosphate4--,after the final ignition of the magnesium pyrophosphate1 whether secured by the citrate or the molybdic method1 a black or grayish tint is often noticed4 ,this may be due to traces of organic matter brought down by the precipitate and especially to a lack of care in the initial ignition4 ,many devices have been proposed for the purpose of avoiding this coloration1 although general experiments have shown that there is no appreciable increase in the weight of the precipitate when colored in this way4 ,when the precipitation is carried on according to the citrate method1 ,neubauer#dg proposes to eliminate this coloration by the use of ammonium sulfate4 ,about seven cubic centimeters of a saturated solution of ammonium sulfate should be added to the solution before the precipitation by the magnesium mixture4 ,with this precaution it is possible to obtain a perfectly white precipitate after five minutes of ignition4 ,the lively glowing of the precipitate throughout the whole mass at the time of changing into pyrophosphate1 is much more easily observed by this treatment than when the mass is gray or black4 ,even should the addition of the ammonium sulfate solution to one containing a large amount of lime produce a precipitate of crystalline calcium sulfate1 it is of no importance inasmuch as the ammonium citrate immediately dissolves large quantities of the calcium salt4 ,in this laboratory a white pyrophosphate is easily obtained by treating the precipitate on the gooch after washing free of chlorids with a drop or two of ammonium nitrate4 ,the ignition is commenced very gently at first and afterwards when the mass is white the blast is used4 ,if the ignited residue be gray it may sometimes be whitened by moistening with a drop or two of nitric acid1 burning at a very low temperature1 followed by the blast4 ,there is no appreciable difference in weight between a gray and white pyrophosphate4 #fb4 ,determination of ,phosphoric ,acid and ,nitrogen in the ,same ,solution by ,treatment with ,sulfuric ,acid and ,mercury4--,fertilizing materials which contain organic nitrogen and phosphoric acid1 such as bones1 are of such a nature that it is often difficult to obtain a fair sample of them in quantities suited to the direct determination2 viz41 about one gram4 ,thus it often becomes important to take a much larger quantity of the material1 to bring it into solution and to take an aliquot part thereof4 ,it may also often happen that it is important to determine the phosphoric acid in the same sample which has been used for the determination of the nitrogen by moist combustion with sulfuric acid and mercury4 ,in this connection1 however1 it is somewhat difficult to avoid the precipitation of some of the mercury with the phosphoric acid4 ,the mercuric sulfate which is produced by the ,kjeldahl method is not precipitated in the presence of ammoniacal solution of ammonium citrate1 but there may be small quantities of mercurous salts present or some finely divided metallic mercury which may contaminate mechanically the phosphate precipitate4 ,these disturbing influences may be removed by previous treatment with sodium chlorid4 ,if from fifty to sixty cubic centimeters of sulfuric acid have been used for the solution and oxidation and this be made up to half a liter1 it will be sufficiently dilute to permit an almost quantitative separation of the mercurous chlorid produced by treatment with sodium chlorid4 ,neubauer1 who has proposed this method1 finds that when sodium chlorid is used previous to the precipitation of the phosphoric acid1 a precipitate of ordinary size contains1 at most1 only one milligram of mercury1 while without the use of sodium chlorid as much as four milligrams may be found4 ,the details of the method employed by ,neubauer are as follows3 ,ten grams of the fertilizing material are placed in a half liter flask with from fifty to sixty cubic centimeters of strong sulfuric acid1 two grams of mercury1 and a little paraffin to prevent foaming4 ,the oxidation is carried on as usual in the ,kjeldahl method4 ,the liquid1 after cooling1 is diluted with water and one cubic centimeter of a citrate solution of sodium chlorid added1 cooled1 filled to the mark1 filtered1 and fifty cubic centimeters taken for the determination of the phosphoric acid1 according to the citrate method and the same quantity for the determination of the ammonia by distillation4 ,,the ,,citrate ,,method4 #fc4 ,general ,principles4--,it has been seen that in the molybdic method there is introduced a process at considerable cost1 both of reagents and time1 having for its object the separation of the phosphoric acid from all the other acids and bases which may have been present in the original sample4 ,the phosphorus is thus obtained in composition with molybdenum and ammonium in a form easily soluble in ammonia1 from which it can be accurately separated by means of a soluble salt of magnesia4 ,the citrate method has for its object the suppression of this intermediate step and the determination of the phosphoric acid by direct precipitation in presence of iron1 lime1 and alumina4 ,the principle on which it is based rests on the well-known power of an alkaline ammonium citrate to hold in solution the salts of iron1 alumina1 and lime1 while at the same time it permits of the separation of phosphoric acid1 as ammonium magnesium phosphate4 ,in no case can the citrate method be regarded as an exact analytical process1 but large experience has shown that the errors of the method are compensatory and that it affords a good and ready method for fertilizer control4 ,when phosphoric acid solutions which contain no iron1 lime1 alumina1 or manganese1 are precipitated in presence of ammonium citrate the results obtained vary markedly with the quantity of magnesia mixture employed4 ,grupe and ,tollens#dh were the first to point out that a portion of the phosphoric acid might remain in solution1 but that the precipitate might contain a sufficient excess of magnesia to compensate for the loss4 ,it has been further shown by ,glaser#di that a portion of the phosphoric acid may be lost by volatilization in the citrate method4 ,when the ignition is carried on in a crucible where the cover is coated with magnesia to intercept the volatilized acid1 a considerable quantity of it can be recovered by the molybdic method4 ,where too little magnesia mixture is employed1 therefore1 two sources of loss are to be guarded against2 viz41 a part of the phosphoric acid may remain in solution and another part be volatilized on ignition4 ,the explanation of the volatilization is as follows3 ,in the presence of ammonium citrate1 magnesium chlorid may be partly converted into magnesium citrate and ammonium chlorid4 ,there may be a time1 therefore1 in the precipitation with not too great excess of magnesia mixture1 when proportionally there is little magnesium chlorid and much ammonium chlorid present4 ,the formation of a salt represented by the formula ,mg7,,nh77,,po7 may take place which1 upon ignition1 breaks up into ,mg7,,po7 and finally passes into ,mg,p,o with loss of ,p,o4 ,this theoretical condition has but little weight1 however1 practically in the analysis of fertilizers1 since in these cases a large quantity of lime is always present4 ,but even in these cases traces of volatile ,p,o may be discovered4 ,wells#ej has shown that the citrate method gives good results in certain conditions but that this accuracy is reached by a fortunate compensation of errors4 ,the ammonium magnesium salt does not precipitate all the phosphoric acid in this process1 but contains enough impurities to make up for this loss4 ,johnson#ea in conjunction with ,osborne has shown that the results by the citrate method practiced in accordance with the details laid down by ,vgel1 are too low1 but that this difficulty could be overcome by using more and stronger magnesia mixture and a larger quantity of strong ammonia solution4 ,the citrate method was found to give unsatisfactory results when iron and alumina were present in any considerable quantity4 ,in the examination of the final ignited precipitate1 which should be pure magnesium pyrophosphate1 it was found to consist of only #id4ih to #ig4hc per cent of that salt4 ,the chief impurity found was calcium oxid1 the percentage of which varied from #b4je to #c4ie in six cases4 ,there was also a considerable percentage of loss due1 probably1 to magnesia and pyrophosphoric acid4 ,the presence of large quantities of iron and alumina also impairs the accuracy of the molybdate method when the precipitation of the yellow salt takes place at too high a temperature4 ,when the temperature of precipitation in the method is above #ej the results are likely to be too high while a great excess of nitric acid in the reagent may produce a contrary effect4 ,in the latter case the filtrate from the yellow salt should be mixed with additional quantities of molybdate solution until no further precipitate takes place4 ,many methods of conducting the citrate method have been proposed but the best of them are based on the one elaborated at the experiment station of ,halle by ,bhring1 and which will be given in the next paragraph1 followed by some other methods in use in other localities4 #fd4 ,method of the ,halle ,agricultural ,experiment ,station4#eb--,the citrate method1 as described by ,morgen1 is the one employed4#ec ,the principle depends upon the direct precipitation of the phosphoric acid by magnesia mixture4 ,by the addition of a solution of ammonium-citrate the precipitation of lime1 iron1 alumina1 and other bases1 is prevented4 ,the precipitate of ammonium magnesium phosphate is converted by ignition into magnesium pyrophosphate and weighed as such4 ,by the use of this method a part of the phosphoric acid sometimes escapes precipitation and a portion of the other bases is sometimes thrown down with the precipitate4 ,experience has shown that by adhering to certain precautions the weight of impurities in the precipitate may be made to correspond exactly to the weight of the phosphoric acid which escapes precipitation4 ,illustration3 ,,figure #c4 ,,shaking ,,apparatus ,,for ,,superphosphates4 7#a7 ,soluble ,acid4--,the soluble phosphates are first brought into solution in such a way that one liter of water contains the soluble phosphoric acid from twenty grams of the substance4 ,twenty grams are rubbed in a porcelain mortar with water and through a wide-necked funnel washed into a bottle-shaped flask in which a little water has been previously placed4 ,the flasks employed are made of thick glass in order to withstand shaking4 ,after the substance is washed1 the flasks are filled to the mark and closed with rubber stoppers4 ,they are then placed upon a shaking rack as indicated in ,fig4 #c1 which is also furnished with an apparatus for separating the fine meal from basic slag4 ,on a table1 as shown in the figure1 is fastened a movable horizontal board by means of hinges4 ,at the left hand of this movable board is placed an open wooden box in which is a perforated shelf for the purpose of holding the flasks1 so as to prevent their striking together during the shaking4 ,for the best results the substance to be examined should be placed in the flask in a dry state and then #hjj cubic centimeters of water added and shaken by means of the machine indicated for half an hour4 ,afterwards the flasks are filled up to the mark1 well shaken1 and filtered through double folded filters into ordinary flasks of about #djj cubic centimeters capacity4 ,before any of the filtrate is collected1 the first that runs through should be well shaken in the receiving flasks and rejected4 ,fifty cubic centimeters of the filtrate thus collected1 corresponding to one gram of the substance1 should be used for the determination4 7#b7 ,total ,acid4--,for total phosphoric acid1 including the insoluble portions1 the material is treated as follows3 ,five grams of the substance are placed in a #ejj cubic centimeter flask with twenty cubic centimeters of nitric acid of #a4db specific gravity1 and fifty cubic centimeters of pure concentrated sulfuric acid1 and boiled briskly for half an hour4 ,with substances which contain much organic material1 a little paraffin is added to avoid frothing4 ,such substances also require a larger quantity of nitric acid than that above specified4 ,the flasks are allowed to cool1 water added1 again allowed to cool1 and filled up to the mark at #ag4e4 ,if hydrochloric instead of sulfuric acid be used in making the above solution1 when the citrate method is employed1 the results are always too high because the precipitate contains lime and alumina in such quantities as to render any compensation for them inaccurate4 ,in addition to this the sulfuric has this great advantage over the hydrochloric acid2 viz41 in not separating silicic acid1 inasmuch as the silicic acid is insoluble in boiling sulfuric acid4 7#c7 ,citrate-,soluble ,acid4--,two grams of the sample are digested with #ajj cubic centimeters of citrate solution1 #a4ji specific gravity1 for half an hour at #ej in a beaker4 ,afterwards the soluble matter is separated by filtration with the aid of a filter-pump and the residue washed with a solution of one part water and one part citrate solution until all the dissolved phosphoric acid is removed from the filter4 ,generally three or four washings are sufficient4 ,the residue on the filter is dried1 ignited1 and dissolved in a mixture of two cubic centimeters of nitric and twenty cubic centimeters of sulfuric acid1 the solution made up to a volume of #bjj cubic centimeters1 filtered1 and #ajj cubic centimeters of the filtrate taken for the determination4 ,the acid in the filtrate is nearly neutralized and fifty cubic centimeters of citrate solution are added1 and afterwards twenty-five cubic centimeters of magnesia mixture and twenty cubic centimeters of twenty-four per cent ammonia4 ,after standing for forty-eight hours1 the precipitate is separated by filtration1 ignited1 and weighed in the usual way4 ,the difference between the total phosphoric acid and that in the insoluble residue1 after treatment with ammonium citrate1 as above1 gives the quantity of phosphoric acid soluble in the citrate solution4 ,the difference between the total citrate-soluble and the water-soluble gives the quantity of the reverted phosphoric acid4 ,the ammonium citrate solution used for the digestion is made as follows3 ,two hundred and fifty grams of crystallized citric acid are dissolved in half a liter of hot water1 diluted with #eej cubic centimeters of water1 #bgf cubic centimeters of twenty-four per cent ammonia added1 and finally1 exactly neutralized by adding1 little by little1 fifty per cent citric acid solution4 ,the ,halle methods of separating the water and citrate-soluble acids appear to be less complete and reliable than those in use by the ,official ,agricultural ,chemists of this country4 ,the precipitation of basic phosphates1 when large quantities of water are used at once in separating soluble acid1 must tend to diminish the quantity obtained1 while the lack of care in assuring the neutrality of the citrate solution might lead to varying results4 7#d7 ,double ,superphosphates4--,in the case of double superphosphates1 which sometimes contain large quantities of pyrophosphate1 the solution is made in the usual way so that in #ajj cubic centimeters there will be contained two grams of the substance4 ,usually ten grains are taken and the volume made up to half a liter4 ,twenty-five cubic centimeters of the filtrate are diluted with seventy-five cubic centimeters of water and the pyro converted to orthophosphoric acid by heating with ten cubic centimeters of strong nitric acid on a sand-bath4 ,the heating should be continued until the volume be reduced to twenty-five cubic centimeters4 ,the strongly acid liquid is made alkaline with ammonia1 and afterwards slightly acid with nitric1 and the rest of the process is carried on in the usual way4 7#e7 ,phosphoric ,acid in the ,residue of ,superphosphate ,manufacture4--,in the mixture of superphosphates and gypsum1 the residue of the manufacture of double superphosphates1 the phosphoric acid is estimated in the following manner3 ,five grams of the substance are placed in a dish1 rubbed up with absolute alcohol1 and washed into a #bej cubic centimeter flask4 ,the flask is filled with absolute alcohol to the mark1 closed with a stopper1 and with frequent shaking1 allowed to stand for two hours2 it is thereupon filtered as quickly as possible2 fifty cubic centimeters of the filtrate corresponding to one gram of the substance1 are taken for the estimation4 ,this fifty cubic centimeters is evaporated on a sand-bath to a sirupy consistence1 diluted with water1 and treated1 as in the case of the soluble phosphates above mentioned4 ,in all cases as described above1 after the solutions are obtained they are treated with the ammonium citrate solution and the phosphoric acid estimated as in the first instance given4 7#f7 ,solutions ,employed4-- 7a7 ,the citrate solution is made as follows3 #a1ejj grams of citric acid are dissolved in water1 treated with five liters of twenty-four per cent ammonia1 and made up to fifteen liters4 7b7 ,the magnesia mixture is made as follows3 #ejj grams of magnesium chlorid1 #a1jej grams of ammonium chlorid1 three and five-tenths liters of twenty-four per cent ammonia1 and six and five-tenths liters of distilled water are used4 ,in the case of the superphosphates fifty cubic centimeters of the citrate solution are employed and with the basic slags #ajj cubic centimeters2 and in both cases twenty-five cubic centimeters of the magnesia mixture4 7#g7 ,details of the ,manipulation4--,on the addition of the citrate solution there should be no permanent troubling of the liquid but there should be a total clearing up thereof4 ,in order to facilitate this1 after the addition of the citrate solution1 the flasks should be gently shaken in order to distribute the solution throughout the mass4 ,solutions from bone-black superphosphates show sometimes1 after the addition of the citrate solution1 a more or less strong opalescence1 but this opalescence does not influence the results4 ,should it happen that with superphosphates which are made from raw material containing large excesses of iron or clay1 fifty cubic centimeters of the citrate solution are not sufficient to prevent the other bases from being precipitated1 an additional quantity up to twenty-five cubic centimeters may be added4 ,the addition of the magnesia mixture must follow as quickly as possible after the addition of the citrate solution to avoid a separation of crystalline calcium phosphate4 ,on the addition of the citrate solution there is always a rise in temperature4 ,inasmuch as the precipitation of the phosphoric acid with magnesia must take place in the cold1 the liquid must be cooled after the addition of the citrate1#ed and the cooling should take place as quickly as possible4 ,the above method was adopted by the chemical section of the ,international ,agricultural ,congress held at ,vienna1 ,september1 #ahij4ee ,illustration3 ,,figure #d4 ,,shaking ,,machine ,,for ,,ammonium ,,magnesium ,,phosphate4 ,in order to hasten the precipitation of the ammonium magnesium phosphate and to prevent the fixation of the precipitate on the walls of the erlenmeyer1 the flask should be shaken for half an hour4 ,for this purpose the flasks should be closed with smooth well-fitting rubber stoppers and placed in a shaking machine4 ,the shaking machine of the form given in ,fig4 #d1 recommended by the ,halle station1 is very conveniently used for this purpose4 ,on a vertical axis are carried two stages for holding the flasks4 ,the flasks are prevented from striking each other by means of the partitions shown4 ,the apparatus is conveniently driven by a small water-motor1 as indicated1 which imparts to the stages a partial back and forth revolution4 ,after shaking for half an hour1 any precipitate adhering to the rubber stoppers is carefully washed off with ammonia water into the flask4 ,the filtration can be made immediately after the shaking or after two or three days2 the results are the same4 ,illustration3 ,,figure #e4 ,r,,ssler ,,ignition ,,furnace4 ,the filtration of the ammonium magnesium phosphate is made through perforated crucibles4 ,the asbestos felt is prepared in the following way3 ,the coarse fibers of asbestos are chopped up with a sharp knife on a glass plate and boiled for two hours with strong hydrochloric acid2 afterwards1 by repeated washing with distilled water they are freed from acid and the too fine particles of asbestos which would tend to make the filter too impervious4 ,after the last wash-water is poured off1 the asbestos is suspended in water and used for making the felt on the filter4 ,the preparation of the crucible and the filtration under pressure are accomplished in the usual way4 ,the ignition of the precipitate is accomplished in a ,rssler ignition oven1 ,fig4 #e4 ,when the muffle of the furnace shows a white heat or a white-red heat it is at the proper temperature for the estimation4 ,at higher temperatures1 the asbestos felt is easily injured4 ,generally1 an ignition of five minutes is sufficient1 but with double superphosphates1 ten minutes are required4 #fe4 ,the ,swedish ,citrate ,method4#ef--,this method of determining phosphoric acid is founded on the fact that phosphoric acid in the presence of calcium salts1 without it being necessary1 previously1 to convert it into phosphomolybdate1 is precipitated directly by magnesia mixture from a solution1 to which ammonium citrate has been added1 provided first1 that the solution contain a sufficient quantity of sulfuric acid1 and second1 that only as much citrate be added as is required to keep the calcium salts in alkaline solution4#eg ,reagents4 7#a7 ,citric ,acid ,solution4--,prepared by dissolving #ejj grams of citric acid in water1 and completing to a volume of one liter4 7#b7 ,ten ,per ,cent ,ammonia of #j4iei specific gravity4 7#c7 ,magnesia ,mixture1 of the usual composition4 ,the various processes are conducted as follows3 7a7 ,water-,soluble ,phosphoric ,acid4--,add twenty cubic centimeters of citric acid solution to fifty cubic centimeters of the water-soluble solution obtained according to the ,swedish molybdenum method1 and then add thirty-three cubic centimeters of ammonia4 ,when the mixture has cooled1 add slowly twenty-five cubic centimeters of the magnesia mixture1 and then forty-two cubic centimeters of the ammonia4 ,keep the solution stirred by means of a closely clipped feather which is pressed tightly against the sides of the beaker2 by this process the phosphate is precipitated after half an hour in pure condition and completely1 without1 in the least1 sticking to the wall of the beaker2 filter1 wash1 and ignite1 as usually directed4 7b7 ,insoluble ,phosphoric ,add4--,moisten1 in a porcelain dish1 ten grams of the powdered sample with water2 add fifty cubic centimeters of concentrated sulfuric acid1 and heat for fifteen minutes so high that fumes of sulfuric acid will escape4 ,when the mass has cooled1 wash it into a half liter graduated flask1 fill to the mark1 and shake well4 ,after filtration1 the clear filtrate may1 after some time1 turn turbid by separation of calcium sulfate1 but as the ammonium citrate1 which is afterwards added1 again brings the precipitate into solution1 it is of no importance4 ,take fifty cubic centimeters of the solution1 corresponding to one gram of the powdered sample1 add twenty cubic centimeters of the citric acid solution1 neutralize the mixture approximately1 but not exactly1 by ammonia2 after cooling1 add twenty-five cubic centimeters of magnesia mixture2 stir the fluid by means of a feather1 as described above1 till no more precipitate is formed1 and finally add thirty-three cubic centimeters of ammonia while stirring for a couple of minutes more2 after half an hour the precipitate may be separated by filtration1 washed1 and ignited1 as usually directed4 ,the above process is essentially the one used with basic slags4 ,when much organic matter is present1 by continuing the heating with sulfuric acid for some time1 it may be destroyed4 #ff4 ,methods ,adopted by the ,brussels ,congress1 #ahid4--,the report of the committee on methods of analysis of phosphoric acid requires the molybdate method to be used in all cases where the quantity to be determined is very small4 ,in other cases the citrate method may be employed4#eh 7#a7 ,soluble ,phosphoric ,acid4--,the soluble phosphoric acid is determined by the method adopted at ,brussels in the following manner3 ,five grams of the sample are rubbed to a powder in a mortar1 and then from fifty to sixty cubic centimeters of water added4 ,after allowing to settle for a few minutes the liquid portion is decanted upon a filter4 ,this operation is repeated three or four times4 ,finally the solid portions are washed upon the filter1 and the washing with water is continued until the filtrate amounts to about three-quarters of a liter4 ,a few drops of hydrochloric acid are added until the filtrate is perfectly clear1 and the volume is then made up to one liter4 ,fifty cubic centimeters of the solution are then treated with thirty cubic centimeters of ammonium citrate solution and one-third as much ammonia4 ,afterwards thirty cubic centimeters of magnesia mixture are added1 drop by drop1 with constant stirring4 ,for superphosphates containing more than eighteen per cent of phosphoric acid only one gram is taken1 for ordinary superphosphates two grams1 and for compound fertilizers four grams4 ,the sample is first treated as above for soluble acid until the filtrate amounts to #bjj cubic centimeters1 then clarified with a drop of nitric acid1 and made up to a quarter of a liter4 7#b7 ,reverted ,phosphoric ,acid4--,the filter containing the residue is then introduced into a quarter liter flask and treated with #ajj cubic centimeters of ,petermann's alkaline ammonium citrate solution1 vigorously shaken1 and left at room temperature for fifteen hours4 ,it is then digested for an hour at #dj and filtered4 ,fifty cubic centimeters of the filtrate are placed in a flask and1 with constant shaking1 thirty-five cubic centimeters of magnesia mixture added4 ,the aqueous solution is treated in the same way4 ,the precipitate is collected1 ignited and weighed1 and multiplied by #j4fd for phosphoric acid4 ,the total acid is determined in the usual way4 #fg4 ,dutch ,method for ,citrate-,soluble ,phosphoric ,acid4#ei--,the reagents necessary are3 7#a7 ,citrate solution1 prepared according to ,petermann4 ,dissolve #afe grams of citric acid in #gjj cubic centimeters of water1 mix with #bej cubic centimeters of ammonia of #j4ib specific gravity1 and1 after cooling1 bring to the volume of one liter4 7#b7 ,magnesia mixture prepared according to ,petermann4 ,dissolve #djj grams of crystallized magnesium chlorid1 #hjj grams of ammonium chlorid1 and #a1fjj cubic centimeters of ammonia of #j4if specific gravity in water1 and dilute to five liters4 ,the quantity to be taken for the analysis is five grams where the fertilizer contains less than six per cent of phosphoric acid 7mixed fertilizers72 two grams where it contains more than six and less than fifteen per cent 7common superphosphates72 and one gram where it contains more than fifteen per cent 7double superphosphates74 ,place the weighed substance in a mortar and cover with #ajj cubic centimeters of citrate solution4 ,gently rub up1 wash into a half liter flask1 and heat in a water-bath for an hour to a temperature between #ce and #ch4 ,allow to cool1 fill up to #ejj cubic centimeters1 and filter through a dry double filter4 ,if it is not clear at the first filtration1 pour through the filter again1 repeating this till clearness is attained4 ,measure #ajj cubic centimeters and add seventy-five cubic centimeters of magnesia mixture1 allowing the latter to flow into the former very slowly1 and constantly stirring during the influx4 ,allow to stand fifteen hours1 filter1 wash with ammonia of #j4if specific gravity1 dry1 ignite1 and weigh4 ,the per cent of phosphoric acid1 except where otherwise indicated1 is always to be given as per cent of anhydrous acid 7,p,o74 #fh4 ,comparative ,accuracy of the ,citrate and ,molybdate ,methods4--,the general use of the citrate method of determining phosphoric acid by the ,german chemists has led ,johnson#fj to review some trials of that method in the ,yale laboratory made as early as #ahhj4 ,these determinations have lately been repeated in comparison with the ordinary molybdate methods with the result that in sixty-seven determinations on bone-dust1 superphosphate1 cotton-hull ashes1 cottonseed-meal1 tankage1 bone-char1 phosphatic guano1 and phosphate rock1 only three citrate results differed from those obtained by the molybdate method by more than three-tenths of one per cent4 ,the greatest discrepancy between the two methods was #j4da per cent1 and the average difference was #j4ji per cent4 ,the citrate method was found to give poor results when iron and alumina were present in considerable quantity4 ,ignited precipitates by the citrate method were found to contain as high as four per cent of lime1 and iron and alumina in small quantities when these bodies were abundant in the original substance4 ,in the molybdate method the rapid precipitation from solutions at #fe was found to give unsatisfactory results and it was found necessary to conduct the process at temperatures between #dj and #ej4 ,with a relative excess of nitric or a relative deficiency of molybdic acid some phosphoric acid may easily escape precipitation4 ,the chief objection to precipitating at #fe is found in the fact that in presence of considerable iron and alumina some of these bodies may be found in the yellow precipitate1 whence they pass to the final ammonium magnesium phosphate4 ,the citrate method1 therefore1 only gives safe results by compensating errors which in every class of phosphates must be empirically determined4 ,the molybdate method gives results too high when iron and alumina are present in considerable quantity and the yellow precipitate is obtained at temperatures above #ej4 ,on the other hand1 if there1 be a great relative excess of nitric acid the results may be too low unless the filtrates from the yellow precipitate be mixed with additional molybdic solution and digested until no further precipitate is formed4 ,comparative determinations made1 by both methods1 by the ,association of ,german ,experiment ,stations have led to the conclusion that both give practically the same results when each one is conducted with the proper precautions peculiar to it4#fa ,in the latter part of #ahib1 at the general meeting of the ,association1 it was declared that the citrate method1 after having been subjected to repeated tests1 was found to be satisfactory1 changing the composition of the solution so that it might have #a1ajj instead of #a1jjj grams of citric acid and four liters of twenty-four per cent ammonia to each ten liters4 ,the data afforded by the citrate method1 when applied to an artificial mixture of known composition1 were more satisfactory than those obtained by the molybdic process4 ,in this laboratory the citrate method has been found to give nearly agreeing results with the old process4 ,it is much shorter and less expensive2 and is recommended most favorably for practical use1 suggesting1 however1 that with every new kind of phosphate or phosphatic fertilizer varying notably in composition from the standard1 the work should be checked at first by comparison with the molybdenum method4 ,,basic ,,phosphatic ,,slags4 #fi4 ,history and ,manufacture4--,the basic process for the manufacture of ,bessemer steel is known in ,europe as the ,thomas or ,thomas and ,gilchrist process1 and the slags rich in phosphate1 one of the waste products of the process1 are known by the same name4 ,in this country all the phosphatic slags which have been made in the manufacture of steel have been obtained working under the patents of ,reese1 and1 when prepared for the market1 are known as odorless phosphate4 ,the only place where these slags have been made in this country is ,pottstown1 ,pennsylvania4 ,in ,europe they are extensively manufactured1 in ,england1 ,france1 and ,germany1 and their use for agricultural purposes has increased until it is quite equal to that of superphosphates4 ,the quantity of basic slag manufactured in ,germany in #ahic was #gej1jjj tons2 in ,england #afj1jjj2 in ,france #aae1jjj1 making the total production of central ,europe about #a1jjj1jjj1 a quantity sufficient to fertilize nearly #e1jjj1jjj acres4 #gj4 ,process of ,manufacture4--,the principle of the process depends upon the arrangement of the furnaces1 by means of which the phosphoric acid in the pig iron is caused to combine with the lime which is used as a flux in the converters4 ,a general outline of the process is as follows3 ,the pigs1 which contain from two to four per cent of phosphorus1 are melted and introduced into a ,bessemer converter lined with dolomite powder cemented with coal-tar1 into which has previously been placed a certain quantity of freshly-burned lime4 ,for an average content of three per cent of phosphorus in the pig iron1 from fifteen to twenty pounds of lime are used for each #ajj pounds of pig iron4 ,as soon as the melted pig iron has been introduced into the converter1 the air-blast is started1 the converter placed in an upright position1 and the purification of the mass begins4 ,the manganese in the iron is converted into oxid1 the silicon into silica1 the carbon into carbon dioxid and oxid1 and the phosphorus into phosphoric acid4 ,by reason of the oxidation processes1 the whole mass suffers a rise of temperature amounting in all to about #gjj above the temperature of the melted iron4 ,at this temperature the lime which has been added1 melts1 and1 in this melted state1 combines with the phosphoric acid1 and the liquid mass floats upon the top of the metallic portion1 which has1 by this process1 been converted into steel4 ,as soon as the process1 which occupies only about fifteen minutes1 is completed1 the fused slag is poured off into molds1 allowed to cool1 broken up1 and ground to a fine powder4 ,for each five tons of steel which are made in this way1 about one ton of basic slag is produced4 ,in another process1 in order to make a slag richer in phosphoric acid1 a lime is employed which contains a considerable percentage of phosphate4 ,although the slag thus produced is richer in phosphoric acid1 it is doubtful whether it is any more available for plant growth than that made in the usual way with lime free from phosphoric acid4 ,in other words1 when a basic slag is made with a lime free from phosphoric acid1 nearly the whole of the phosphoric acid is combined as tetrabasic calcium phosphate4 ,on the other hand1 when the lime employed contains some of the ordinary mineral phosphate the basic slag produced becomes a mixture of this mineral phosphate with the tetracalcium salt4 ,the mineral phosphate is probably not rendered any more available than it was before4 ,it is easily seen from the above outline of the process of manufacture1 that basic slags can have a very widely divergent composition4 ,when made from pig iron poor in phosphorus1 the slag will have a large excess of uncombined lime and consequently the content of phosphoric acid will be low4 ,when made from pigs rich in phosphorus there may be a comparative deficiency of lime1 and in this case the content of phosphoric acid would be unusually high4 ,it is found also that the content of iron in the slag varies widely4 ,in general1 the greater the content of iron the harder the slag and the more difficult to grind4 ,if the pig iron contain sulfur1 as is often the case1 this sulfur is found also in the slag in combination with the lime1 either as a sulfid or sulfate4 ,no certain formula can therefore be assigned to basic slags and the availability of each one must be judged by its chemical composition4 #ga4 ,composition of ,basic ,slag4--,the slags produced by the method above outlined may be amorphous or crystalline4 ,when large masses are slowly cooled the interior often discloses a crystalline composition4 ,in some samples analyzed in this laboratory the crystals were found to be of two forms2 viz41 acicular and tabular4#fb ,they had the following composition3 ,,calculated ,,per ,,cents ,,as ,ca,o4 ,fe,o4 ,al,o4 ,mg,o4 ,v,o4 ,p,o4 ,si,o4 ,acicular crystals #db4fi #bj4ih #c4ga #j4di #j4ah #bg4jf #d4if ,tabular crystals #ec4fa #i4fd #j4ia #j4jh ---- #cc4ib #a4ge ,these data show that the two sets of crystals belong to two distinct mineral forms4 ,the presence of vanadium in one of the samples is worthy of remark1 and leads to the suggestion that in the slags made of phosphoriferous pigs may be found any of the rare metals which may exist in the ores from which the pigs were made4 ,the amorphous portions may have a widely varying composition and consequent content of phosphoric acid4 ,in all good slags1 however1 whether in crystalline form or as amorphous powder1 the lime and phosphoric acid will be found combined as tetracalcium phosphate 7,ca,p,o74 #gb4 ,molecular ,structure of ,tetracalcium ,phosphate4--,several theories have been advanced in respect of the atomic arrangement of the elements contained in a molecule of tetracalcium phosphate4 ,it must be confessed that so little is known concerning the reactions of this body as to make theories of its constitution largely visionary4 ,but the existence in definite crystalline form of this salt shows that it is not merely an intimate mechanical mixture1 but a true molecular form4 ,as a type of the supposed arrangement of its particles the graphic formula proposed by ,kormann may be consulted2 viz41 ,illustration ,the crystals of this salt1 as may be seen by inspection of the analytical data1 contain other bodies than calcium1 oxygen1 and phosphorus4 ,it would be of interest to push the investigation of their constitution further and see if crystals of pure tetracalcium phosphate could be obtained1 and under what conditions they would be contaminated by other metallic oxids4 ,usually1 by the color of the crystals1 it will be easy to determine something of the nature1 if not the extent of the contamination4 #gc4 ,solubility of ,phosphatic ,slags4--,the high agricultural value of basic slags led to an early study of their solubility in ammonium citrate1 citric acid1 and other organic solutions4 ,even finely ground mineral phosphates and bones are soluble to some extent in ammonium citrate1 as was pointed out as long ago as #ahhb4fc ,the most common solvents used for basic slags are ammonium citrate and citric acid4 ,the ammonium citrate should be the same as that used for the determination of reverted phosphoric acid and the citric acid solution commonly used contains five grams in a hundred cubic centimeters4 ,the slags of different origin and even of different age vary greatly in respect of the quantity of soluble matter they contain4 ,it is believed1 however1 that a very fair idea of the agricultural value of a slag may be obtained by determining its degree of solubility in one of the menstrua named4 #gd4 ,separation by ,sifting4--,the relative availability of a slag1 as in the case of a mineral phosphate1 is determined by the percentage of fine material it contains4 ,sieves of varying apertures are used to determine this percentage4 ,a one-half millimeter or a one-quarter millimeter circular aperture is best1 and the percentage of the total material passing through is determined4 ,a method used in ,germany consists in sifting the slag in a sieve twenty centimeters in diameter the meshes of which are from #j4ad to #j4ag millimeter square and which measure diagonally from #j4bb to #j4bd millimeter4 #ge4 ,solution of ,phosphatic ,slags4--,sulfuric acid has been found to be an excellent solvent for basic slags preparatory to the determination of phosphoric acid4 ,there is1 however1 no unanimity of opinion concerning the best method or means of solution4 ,aqua regia and nitric acid are objected to because they may convert any phosphorus in combination with the iron into phosphoric acid and thus increase the quantity present4#fd ,but iron phosphid is seldom or ever found in slags and therefore this objection is not always tenable4 ,sulfuric acid has also been deemed objectionable because the gypsum separated is likely to carry with it some of the other substances to be determined4 ,hydrochloric acid is also excluded by some from the list of solvents because it dissolves so many of the foreign elements in the slag and thus tends to complicate the subsequent determination1 especially of magnesia4 ,further than this a hydrochloric acid solution is not suited to the use of the citrate method now so commonly employed4 ,when hydrochloric acid is used1 moreover1 the dissolved silica must be removed and thus the time required for making a phosphoric acid determination is much increased4 ,if the sample be sufficiently fine the occlusion of undissolved phosphate particles by the gypsum formed when sulfuric acid is used is not to be feared and the disturbance of volume by the gypsum is pretty nearly constant and can be allowed for4 ,when five grams of slag are used the mean volume of gypsum in the solution is about two cubic centimeters4 #gf4 ,estimation of ,total ,acid4--,in the determination of total phosphoric acid in a slag1 twenty-five cubic centimeters of the strongest sulfuric acid are placed in an erlenmeyer having a wide neck1 and with careful shaking five grams of the fine slag meal gradually added4 ,the flask is heated over a naked flame until solution is complete4 ,when the mass is cold it is washed into a quarter liter flask2 again allowed to cool1 filled with water to the mark1 and two cubic centimeters of water corresponding to the volume of gypsum undissolved1 are added1 well mixed1 and filtered4 ,in fifty cubic centimeters of the filtrate the phosphoric acid is determined by either the molybdic or citrate methods already described4 #gg4 ,alternate ,method4--,the following method may also be used3 ,ten grams of the substance are heated with fifty cubic centimeters of concentrated sulfuric acid until white vapors have been evolved for some time4 ,the operation lasts for about fifteen minutes and can be carried on in a half liter flask or in a porcelain dish4 ,without regarding the undissolved material the volume of the liquid is now made up to half a liter and filtered4 ,the filtered liquid becomes turbid after some time through the separation of calcium sulfate1 but this turbidity should not be regarded4 ,to fifty cubic centimeters of the solution1 corresponding to one gram of substance1 twenty cubic centimeters of citric acid solution 7#ejj grams citric acid to the liter7 are added1 and it is afterwards nearly neutralized by the addition of ten per cent ammonia and the liquid1 which is warmed by this operation1 cooled4 ,there are now added twenty-five cubic centimeters of the ordinary magnesium chlorid mixture and the solution stirred until turbidity is produced1 one-third of its volume of ten per cent ammonia added1 and again stirred for about a minute4 ,instead of the addition of the citric acid and ammonia the ammonium citrate prepared as follows1 may be added3 #a1ejj grams of citric acid are dissolved with water1 made up to three liters and five liters of twenty-four per cent ammonia and seven liters of water added4 ,the rest of the operation is carried on in the usual manner4 #gh4 ,halle ,method for ,basic ,slag4--,the total phosphoric acid is estimated at the ,halle ,station by the following process3#fe ,ten grams of the substance are moistened in a porcelain dish with a few drops of water and about five cubic centimeters of a one to one solution of sulfuric acid added1 and after the mass has hardened1 which takes place very soon1 fifty cubic centimeters of concentrated sulfuric acid are added and stirred with a glass rod until it is evenly distributed throughout the whole mass4 ,in stirring this mixture the greatest care must be taken1 otherwise the substance would remain attached to the sides of the dish1 which during later heating would cause loss through spurting4 ,the complete solution now takes place after a few hours' heating on a sand-bath4 ,during the cooling the jelly-like mass must be stirred with a glass rod1 and after it is cool1 by means of a washing-bottle1 gently along the sides of the dish1 water is added1 and when the mixture becomes hot it is again cooled and washed into a half liter flask1 which is made up to the mark at a temperature of #ag4e and filtered4 ,when the acid filtrate stands for some time there is often a separation of gypsum which1 however1 does not in any way influence the subsequent analysis1 which is made in the usual manner4 ,fifty cubic centimeters of the filtrate1 representing one gram of the original substance1 are placed in an erlenmeyer4 ,in the case of double superphosphates which often contain large quantities of pyrophosphates1 twenty-five cubic centimeters of the filtrate just obtained1 equivalent to five grams of the substance1 are diluted with seventy-five cubic centimeters of water1 ten cubic centimeters of nitric acid of #a4db specific gravity added1 and heated on a sand-bath to convert the pyro into orthophosphates4 ,the heating should be continued until the liquid is reduced to its original volume of twenty-five cubic centimeters4 ,the strongly acid liquid is saturated with ammonia and with the addition of a drop of rosolic acid as an indicator1 again acidified with nitric acid1 and treated as with superphosphates4 #gi4 ,dutch ,method for ,basic ,slag4--,heat ten grams of the sample with fifty cubic centimeters of sulfuric acid 7#a4hd specific gravity7 till white vapors are evolved1 shaking or stirring constantly4 ,after cooling make the fluid up to #ejj cubic centimeters with water1 taking no account of the undissolved substance4 ,filter1 and to fifty cubic centimeters of the filtrate add #ajj cubic centimeters of the ammoniacal citrate solution1 and after cooling1 twenty-five cubic centimeters of magnesia mixture4 ,stir or shake for a sufficient time4 ,after the lapse of two hours the precipitate is to be separated by filtration and treated in the usual manner4 #hj4 ,estimation of ,citrate-,soluble ,phosphoric ,acid in ,basic ,slag4--,experience has shown that the manurial value of basic slags does not depend alone on their content of phosphoric acid4 ,slags may contain tri- as well as tetracalcium phosphate1 and even this latter salt may exist in states of differing availability4 ,in determining the availability of basic slag for manurial purposes its solubility in ammonium citrate is considered the best standard4 ,but this solubility will evidently be influenced by the basicity of the sample1 or in other words1 by the quantity of lime present4 ,a slag rich in calcium oxid would deport itself differently with a given ammonium citrate solution from one in which the lime had been chiefly converted into carbonate4 ,if possible1 therefore1 all samples should be reduced to the same state of basicity before the action of any given solvent is determined4 ,wagner proposes to neutralize the basicity of a slag in the following manner3#ff ,five grams of the slag are placed in a half liter flask which is then filled up to the mark with a one per cent solution of citric acid and shaken for half an hour4 ,after filtering1 fifty cubic centimeters are titrated with a standard soda solution using phenolphthalein as indicator4 ,this gives the quantity of citric acid necessary to neutralize the slag4 ,to a second portion of five grams of the sample in a half liter flask are added #bjj cubic centimeters of water and enough five per cent citric acid solution to neutralize the lime and then #bjj cubic centimeters of acid ammonium citrate made as indicated below4 ,after filling to the mark with water it is shaken for half an hour and filtered4 ,to fifty cubic centimeters of the filtrate are added #ajj cubic centimeters of molybdic solution and heated to #hj4 ,after cooling1 the precipitate is filtered and the phosphoric acid estimated in the usual way4 ,the acid ammonium citrate solution used is made as follows3 ,dissolve #afj grams of citric acid with enough ammonia to represent about twenty-eight grams of nitrogen and make up with water to one liter4 ,the exact method is given in #hb4 ,the molybdic solution is made by dissolving #abe grams of molybdic acid in a slight excess of two and a half per cent of ammonia1 adding #djj grams of ammonium nitrate1 diluting to one liter and pouring the solution into one liter of nitric acid having a specific gravity of #a4ai4 ,after allowing to stand at room temperature for one day the mixture is filtered and is then ready for use4 #ha4 ,wagner's ,shaking ,apparatus4--,the latest directions given by ,wagner for determining the phosphoric acid in slags and raw phosphates soluble in citrate solutions1 are the following3#fg ,five grams of the material as it is sent into commerce without grinding or sifting1 are placed in a half liter flask and covered with nearly a quarter liter of water1 and then #bjj cubic centimeters of citrate solution added1 prepared as described below4 ,the flask is filled to the mark with water4 ,the flasks1 which are of the shape shown in the figure1 are closed with rubber stoppers1 and without delay placed for half an hour in a rotating apparatus1 7,fig4 #f7 which is turned on its axis from thirty to forty times a minute4 ,if a shaking apparatus be used instead of the one mentioned1 #bjj cubic centimeters of the citrate solution should be placed in a half liter flask1 filled to the mark with water1 and the contents poured into a liter flask containing the phosphate4 ,this flask should be placed in a nearly horizontal position in the apparatus and the agitation be continued for half an hour4 ,on removal from the apparatus the mixture is filtered and fifty cubic centimeters thereof treated with double the quantity of molybdic solution at #hj and the precipitate separated after cooling4 ,the precipitate is carefully washed with one per cent nitric acid mixture1 after which the filter is broken and the precipitate washed into a beaker with two per cent ammonia and the filter washed therewith until about #ajj cubic centimeters have been used4 ,if the solution is turbid from the presence of silicic acid it should be precipitated a second time by addition of molybdic solution until the acid reaction is restored4 ,the ammoniacal solution of the yellow precipitate is treated1 drop by drop1 with constant stirring1 with fifteen cubic centimeters of magnesia mixture1 and set aside for two hours4 ,the precipitate is collected1 washed1 ignited1 and weighed in the usual manner4 ,the direct precipitation of the phosphoric acid by the magnesia solution in presence of citrate is not advisable because of the almost general presence of silicic acid which would cause the results to be too high4 ,illustration3 ,,figure #f4 ,,wagner',s ,,digestion ,,apparatus ,,for ,,slags4 ,the chief objection to this method of ,wagner lies in the failure to control the temperature at which the digestion with citrate solution is made4 ,huston has shown1 as will be described further on1 that the temperature exercises a great influence in digestion with citrate4 ,since the laboratory temperature1 especially in this country1 may vary between #aj and #ce1 it is evident that on the same sample the ,wagner method would give very discordant results at different seasons of the year4 #hb4 ,solutions ,employed in the ,wagner ,method4--#a4 ,ammonium ,citrate4--,in one liter there should be exactly #aej grams of citric acid and #bg4ic grams of ammonia1 equivalent to twenty-three grams of nitrogen4 ,the following example illustrates the preparation of ten liters of the solution3 ,in two liters of water and three and a half liters of eight per cent ammonia1 #a1ejj grams of citric acid are dissolved and the cooled solution made up exactly to eight liters4 ,dilute twenty-five cubic centimeters of this solution to #bej cubic centimeters and treat twenty-five cubic centimeters of this with three grams of calcined magnesia and distill into forty cubic centimeters of half normal sulfuric acid4 ,suppose the ammonia nitrogen found correspond to twenty cubic centimeters of fourth normal soda-lye4 ,then in the eight liters are contained 7#bj4j #j4jjce #hjjj7 ---------------------- #bbd grams #b4e of ammonia nitrogen4 ,then in order to secure in the ten liters the proper quantity of ammonia there must be added two liters of water containing #bcj - #bbd six grams of nitrogen or seven and three-tenths grams ammonia2 viz41 ninety-four cubic centimeters of #j4ifg specific gravity4 #b4 ,molybdate ,solution4--,dissolve #abe grams of molybdic acid in dilute two and five-tenths per cent ammonia1 avoiding a large excess of the solvent4 ,add #djj grams of ammonium nitrate1 dilute with water to one liter and pour the solution into one liter of nitric acid of #a4ai specific gravity4 ,allow the preparation to stand for twenty-four hours at #ce and filter4 #c4 ,magnesia ,mixture4--,dissolve #aaj grams of pure crystallized magnesium chlorid and #adj grams of ammonium chlorid in #gjj cubic centimeters of eight per cent ammonia and #acj cubic centimeters of water4 ,allow to stand several days and filter4 #hc4 ,estimation of ,lime4--,when the lime is to be determined in basic slags some difficulty may be experienced by reason of danger of contamination of the oxalate precipitate with iron and especially manganese1 which is often present in slags4 ,holleman#fh proposes to estimate the lime in basic slag by a modification of the methods of ,classen and ,jones4 ,the manipulation is as follows3 ,fifty cubic centimeters of the solution of slag1 equivalent to one gram of substance1 are evaporated to a small volume1 twenty cubic centimeters of neutral ammonium oxalate solution 7one to three7 added to the residue and heated on a water-bath with frequent stirring1 until the precipitate is pure white and free from lumps4 ,the time required is usually about ten minutes4 ,the precipitate is collected on a filter and washed with hot water until the filtrate contains no oxalic acid4 ,the precipitated calcium oxalate must be snow-white4 ,the filter is broken and the calcium oxalate washed through1 first with water and finally with warm1 dilute hydrochloric acid 7one to one74 ,the calcium oxalate is dissolved by adding fifteen cubic centimeters of concentrated hydrochloric acid1 the solution evaporated to a volume of about twenty-five cubic centimeters and ten cubic centimeters of dilute sulfuric acid 7one to five71 and #aej cubic centimeters of ninety-six per cent alcohol added4 ,after standing three hours or more the precipitate is separated by filtration and washed with ninety-six per cent alcohol until the washings show no acid reaction with methyl orange4 ,the calcium sulfate precipitated is dried to constant weight4 ,this method gives a pure precipitate of calcium sulfate1 containing only traces of manganese4 #hd4 ,estimation of ,caustic ,lime4--,the lime mechanically present in basic slags is likely to be found as oxid or hydroxid1 especially when the sample is of recent manufacture4 ,in the form of oxid the lime may be determined by solution in sugar4 ,in this process one gram of the fine slag meal is shaken for some time with a solution of sugar1 as suggested by ,stone and ,scheuch4#fi ,the dissolved lime is separated as oxalate by treatment of the solution with the ammonium salt4 ,the calcium oxalate may be determined by ignition in the usual way or volumetrically by solution in sulfuric acid and titration of the free oxalic acid with potassium permanganate solutions4 ,the standard solution of permanganate should be of such a strength as to have one cubic centimeter equivalent to about #j4ja gram of iron4 ,the iron value of the permanganate used multiplied by #j4e will give the quantity of calcium oxid found4 #he4 ,detection of ,adulteration of ,phosphatic ,slags4--,the high agricultural value of phosphatic slags has led to their adulteration and even to the substitution of other bodies4 ,several patents have also been granted for the manufacture of artificial slags of a value said to be an approximation to that of the by-products of the basic pig iron process4 7#a7 ,method of ,blum4--,one of the earliest methods of examining basic slag for adulterations is the method of ,blum4#gj ,this method rests upon the principle of the determination of the carbon dioxid in the sample4 ,the basic phosphatic slag is supposed to contain no carbon dioxid4 ,this is true only in case it is freshly prepared4 ,the tetrabasic phosphate1 after being kept for some time1 gradually absorbs carbon dioxid from the air4 ,as high as nineteen per cent of carbon dioxid have been found in slags which have been kept for a long while4 ,when the slag has absorbed so much of carbon dioxid and water from the air as to be no longer profitable for market1 it can be restored to its original condition by ignition4 7#b7 ,method of ,richter-,forster4--,one of the common adulterants of tetrabasic phosphate is aluminum phosphate4 ,the method of detecting this when mixed with the slag is described by ,richter-,forster4#ga ,the method depends on the fact that soda-lye dissolves the aluminum phosphate1 although it does not dissolve any calcium phosphoric acid from the slag4 ,two grams of the sample to be tested are treated with ten cubic centimeters of soda-lye of from #g to #h ,c4 in a small vessel with frequent shaking for a few hours at room temperature4 ,after filtration the filtrate is made acid with hydrochloric and afterwards slightly alkaline with ammonia4 ,with pure basic slag there is a small trace of precipitate produced1 but this is due to a little silica which can be dissolved in a slight excess of acetic acid4 ,if1 however1 the basic slag contain aluminum phosphate1 a dense jelly-like precipitate of aluminum phosphate is produced4 7#c7 ,method of ,jensch4--,edmund ,jensch#gb determines the tetrabasic phosphate in slags by solution in organic acids1 and prefers citric acid for this purpose4 ,this method was also recommended by ,blum#gc4 ,it is well known that the tetrabasic phosphate in slags is completely soluble in citric acid while the tribasic phosphate is only slightly1 if at all1 attacked4 ,the neutral ammonium salts of organic acids do not at first attack the tribasic phosphate at all1 and they do not completely dissolve the tetrabasic phosphate4 ,the solution used by ,jensch is made as follows3 ,fifty grams of crystallized citric acid are dissolved in one liter of water4 ,a weaker acid dissolves the tetrabasic phosphate too slowly and a stronger one attacks the tribasic phosphate present4 ,schucht recommends the following method of procedure3#gd ,one gram of the slag1 finely ground1 is treated in a beaker glass with about #aej cubic centimeters of ,jensen's citric acid solution and warmed for twelve hours in an air-bath at from #ej to #gj with frequent shaking4 ,afterwards it is diluted with #ajj cubic centimeters of water1 boiled for one minute and filtered4 ,the filter is washed thoroughly with hot water and the phosphoric acid is estimated in the filtrate in the usual way4 ,with artificial mixtures of basic slags and other phosphates the quantity of basic slag can be determined by the above method4 7#d7 ,method of ,wrampelmeyer4--,according to ,wrampelmeyer the most convenient method for discovering the adulteration of basic slag is the use of the microscope4#ge ,all finely ground natural phosphates are light colored and with a strong magnification appear as rounded masses4 ,in basic slags the particles are mostly black but there are often found red-colored fragments having sharp angles which refract their light in a peculiar way so that1 with a very little experience1 they can be recognized as being distinctive marks of pure basic slag4 ,in artificial mixtures of these two phosphates1 which we have made in our laboratory1 we have been able to detect with certainty as little as one per cent of added mineral phosphate4 ,one form of adulterating natural mineral phosphates has been mixing them with finely pulverized charcoal or soot to give them the black appearance characteristic of the basic slags4 ,this form of adulteration is at once disclosed by simple ignition or by microscopic examination4 7#e7 ,loss on ,ignition4--,if all doubts cannot be removed by the use of the microscope1 the loss on ignition should be estimated4 ,natural phosphates all give a high loss on ignition1 ranging from eight to twenty-four per cent1 while a basic slag gives only a very slight loss on ignition1 especially when fresh4 ,a basic slag which has stood for a long while and absorbed carbon dioxid and moisture1 may give a loss on ignition approximating1 in a maximum case1 the minimum loss on ignition from a natural phosphate4 ,in experiments made in this laboratory in testing for loss on ignition1 we have uniformly found that natural mineral phosphates will lose from nearly one to two and one-half times as much on ignition as a basic slag which has been kept for two years4 ,a basic slag in the laboratory more than two years old gave1 as loss on ignition1 #d4ab per cent4 ,several samples of finely ground ,florida phosphates gave the following percentages of loss on ignition1 as compared with a sample of slag4 ,odorless phosphate #d4ab4 ,florida phosphates #h4jf1 #f4ij1 #i4eh1 #f4dj1 #aj4ch1 and #aj4fg respectively4 ,there are some mineral phosphates1 however1 which are ignited before being sent to the market4 ,we have one such sample in our laboratory from ,florida which gave1 on ignition1 a loss of only one and four-tenths per cent4 ,in this case it is seen that the application of the process of ignition would not discriminate between a basic slag and a mineral phosphate4 ,it may often be of interest to know what part of the loss1 on ignition1 is due to water in form of moisture4 ,in such cases the sample should first be dried to constant weight in a steam-bath and then ignited4 ,in the following data are found the results obtained here with samples treated as above indicated and also ignited directly4 ,number one is a basic slag two years old and the others ,florida phosphates4 ,heated to #ajj ,c4 then ignited4 ,ignited directly4 ,loss at ,loss on ,total ,loss on #ajj ,c4 ignition4 loss4 ignition4 ,no4 #a 7,slag7 #b4eg #a4gg #d4cd #d4ab ,no4 #b 7,rock7 #b4fa #e4ai #g4hj #h4jf ,no4 #c 8 #a4ji #e4gg #f4hf #f4ij ,no4 #d 8 #j4db #i4bj #i4fb #i4eh ,no4 #e 8 #a4ha #d4hc #f4fd #f4dj ,no4 #f 8 #d4cf #f4eb #aj4hh #aj4hc ,no4 #g 8 #c4ca #g4ja #aj4cb #aj4fg 7#f7 ,presence of ,sulfids4--,another point noticed in this laboratory is that the basic slags uniformly contain sulfids which are decomposed upon the addition of an acid with an evolution of hydrogen sulfid4 7#g7 ,presence of ,fluorin4--,in applying the test for fluorin1 it has been uniformly found here that the mineral phosphates respond to the fluorin test while the basic slags1 on the contrary1 respond to the hydrogen sulfid test4 ,this test1 however1 was applied only to the few samples we have had and may not be a uniform property4 ,the absence of fluorin might not prove the absence of adulteration1 but its presence would1 ,i believe1 certainly prove the fact of the adulteration in that particular sample4 ,the fluorin test is applied by ,bttcher in the following manner3#gf ,from ten to fifteen grams of the slag are placed in a beaker ten centimeters high and from five to six centimeters in diameter1 with fifteen cubic centimeters of concentrated sulfuric acid1 stirred with a glass rod1 and covered with a watch-glass on the under side of which a drop of water hangs4 ,if there be formed upon the drop of water a white murky rim1 it is proof that a mineral phosphate containing fluorin has been added4 ,after from five to ten minutes you can notice on the clean watch-glass the etching produced by the hydrofluoric acid4 ,according to ,bttcher an adulteration of ten per cent of raw phosphate in slag can be detected by this method4 7#h7 ,solubility in ,water4--,solubility in water is also a good indication1 natural phosphates being totally insoluble in water1 while a considerable quantity of the basic slag will be dissolved in water on account of the calcium oxid or hydroxid which it contains4 ,if the loss on ignition is low1 and the volume-weight and water-solubility high1 the analyst may be certain that the sample is a pure slag4 ,in comparative tests made in our laboratory with a sample of basic slag and seven samples of ,florida phosphate1 the percentages of material dissolved by water and by a five per cent solution of citric acid were found to be as follows3 ,sol4 in five per cent ,water-soluble4 citric acid4 ,per cent4 ,per cent4 ,odorless phosphate #j4ig #af4aj ,florida phosphate #j4ja #d4ae 8 8 #j4ji #d4ff 8 8 #j4jb #c4dc 8 8 #j4jh #c4fa 8 8 #j4jb #c4gi 8 8 #j4je #d4df 8 8 #j4jb #d4bd ,from the above data it is seen that the solvent action of water especially would be of value inasmuch as it dissolves only a mere trace of the mineral phosphates1 approximating one per cent of the amount dissolved from basic slag4 ,in the case of the citric acid it is found that the amount of materials soluble in this solvent for basic slag is fully four times as great as for the mineral phosphates4 ,both of these processes1 therefore1 have considerable value for discriminating between the pure and adulterated article of basic slag4 7#i7 ,specific ,gravity4--,the estimation of the volume specific gravity is also a good indication for judging of the purity of the slag4 ,this is best done by weighing directly a given volume4 ,basic slag will have a volume-weight of about one and nine-tenths1 while natural phosphates will have about one and six-tenths4 7#aj7 ,conclusions4--,from the above rsum of the standard methods which are in use for determining the adulteration of basic slag1 it is seen that there are many cases in which grave doubt might exist even after the careful application of all the methods mentioned4 ,if we had only to consider the adulteration of basic slag with certain of the mineral phosphates1 that is1 tricalcium phosphate1 the problem would be an easy one1 but when we add to this the fact that iron and aluminum phosphates are employed in the adulteration1 and that artificial slags may be so used1 the question becomes more involved4 ,in doubtful cases one after another of the methods should be applied until there is no doubt whatever of the judgment which should be rendered4 ,,volumetric ,,determination ,,of ,,phosphoric ,,acid4 #hf4 ,classification of ,methods4--,the time required for a gravimetric determination of phosphoric acid has led analysts to try the speedier if less accurate processes1 depending on the use of volumetric methods4 ,the chief difficulty with these methods has been in securing some sharp method of distinguishing the end reaction4 ,in most cases it has been found necessary to remove a portion of the titrated solution and prepare it for final testing by subsidence or filtration4 ,as is well known1 this method of determining the end reaction is less accurate and more time-consuming than those processes depending on a change of color in the whole mass4 ,all the volumetric processes now in general use may be divided into two classes2 viz41 7#a7 the direct precipitation of phosphoric acid and the determination of the end reaction by any appropriate means1 and 7#b7 the previous separation of the phosphoric acid1 usually by means of a citro-magnesium or molybdenum mixture1 and in the latter case the subsequent titration of the yellow ammonium phosphomolybdate either directly or after reduction to a lower form of oxidation4 ,in respect of extent of application by far the most important volumetric method is the one depending on titration by a uranium salt after previous separation by ammoniacal magnesium citrate4 ,a promising method after previous separation by molybdenum is the one proposed by ,pemberton1 but it has not yet come into general use4 ,for small quantities of phosphoric acid or of phosphorus1 such as are found in steels and irons1 the method of ,emmerton1 either as originally proposed or as modified by ,dudley and ,noyes1 is in frequent use4 ,where volumetric methods are applied to products separated by molybdic solution1 the essential feature of the analytical work is to secure a yellow precipitate of constant composition4 ,if this could be uniformly done such methods would rival the gravimetric processes in accuracy4 ,hence it is highly important in these methods that the yellow precipitate should be secured as far as possible1 under constant conditions of strength of solution1 duration of time1 and manner of precipitation4 ,in these cases1 and in such only1 can the quicker volumetric methods be depended on for accurate results4 ,the direct volumetric precipitation of the phosphoric acid by a uranium salt or otherwise is practiced only when the acid is combined with the alkalies and when iron and alumina are absent and only small quantities of lime present4 ,this method has therefore but little practical value for agricultural purposes4 ,in all volumetric analyses the accuracy of the burettes1 pipettes1 and other graduated vessels should be proved by careful calibration4 ,many of the disagreements in laboratories where the analytical work is conducted equally well can be due to no other cause than the inaccuracy of the graduated vessels which are found in commerce4 ,burettes should not only be calibrated for the whole volume but for at least every five cubic centimeters of the graduation4 ,,uranium ,,method ,,as ,,practiced ,,by ,,the ,,french ,,chemists4 #hg4 ,the ,uranium ,method4--,since the phosphoric acid of practical use for agricultural purposes is nearly always combined with lime1 alumina1 and iron1 its volumetric estimation by means of a standard solution of a uranium salt is to be preceded by a preliminary separation by means of an ammoniacal magnesium citrate solution4 ,the principle of the method was almost simultaneously published by ,sutton1#gg ,neubauer1#gh and ,pincus4#gi ,the phosphoric acid may also be separated by means of molybdic solution or by tin or bismuth4#hj ,in practice1 however1 it has been found that when the uranium method is to be used the magnesium citrate separation is the most convenient4 ,since this is the method practiced almost universally in ,france1 the method there used will be given in detail4 ,it is based essentially on the process described by ,joulie4#ha #hh4 ,preparation of ,sample4--7#a7 ,incineration4--,since the organic matters present in a phosphatic fertilizer often interfere with the employment of uranium as a reagent1 it is necessary to incinerate the sample taken for analysis4#hb 7#b7 ,solution of the ,material4--,all phosphates1 with the exception of certain aluminum phosphates1 amblygonite for example1 are easily dissolved in nitric and hydrochloric acids more or less dilute1 especially on ebullition4 ,the best solvent1 however1 for calcium phosphates for the uranium method is incontestably hydrochloric acid which also very easily dissolves the iron and aluminum phosphates1 which are often found present with calcium phosphates4 7#c7 ,nitric ,acid4--,in many laboratories nitric acid is preferred in order to avoid1 in part1 the solution of ferric oxid which interferes with the determination of phosphoric acid in certain processes4 ,since it does not act in this way for the citro-magnesium uranium method1 it is preferable to employ hydrochloric acid1 especially because it dissolves the iron completely and permits thus the operator to judge of the success of the solvent action by the completely white color of the residue4 7#d7 ,pyritic ,phosphates4--,certain phosphates contain pyrites which hydrochloric acid does not dissolve1 and there is left consequently1 a residue more or less colored4 ,in this case it is necessary to add some nitric acid and to prolong the boiling until the pyrite has disappeared1 since it might retain a small quantity of phosphoric acid in the state of iron phosphate4 7#e7 ,sulfuric ,acid4--,some chemists decompose the phosphates by means of dilute sulfuric acid4 ,this method1 which is certainly able to give good results for certain products and for certain processes1 presents numerous inconveniences which tend to render its use objectionable for volumetric purposes4 ,the calcium sulfate which is formed1 requires prolonged washings which lead to chances of fatal error4 ,if an aluminum phosphate be under examination1 containing only very little or no lime1 sulfuric acid is to be preferred to hydrochloric and nitric acids1 since it attacks amblygonite1 which1 as has been before stated1 resists the action of the other two acids4 ,but these are cases which are met with very rarely1 and which can always be treated by the general method by previously fusing the material with a mixture of sodium and potassium carbonate4 ,in the great majority of cases the decomposition by hydrochloric acid is very easily accomplished by simply boiling in a glass vessel1 and without effecting the separation of the silica4 ,this operation is only necessary after the substance has been fused with alkaline carbonates1 or1 in case of substances which contain decomposable silicates giving gelatinous silica with hydrochloric acid4 ,there are two methods see 7#f7 and 7#g7 of securing a solution of the sample taken which varies from one to five1 and even ten grams1 according to the apparent homogeneity of the material to be analyzed4 7#f7 ,solution by ,filtration and ,washing4--,the ordinary method can be employed consisting in decomposing the substance by an acid1 filtering1 and washing the residue upon the filter1 and combining all the wash-waters to make a determinate volume4 ,afterwards an aliquot fraction of the whole is taken for the precipitation4 ,this method is long1 and presents some chances of error1 when the insoluble residue is voluminous and contains silica which obstructs the pores of the paper and renders the filtration difficult4 7#g7 ,volumetric ,solution4--,it is advisable to substitute volumetric solution for solution by filtration and washing1 which is accomplished by decomposing the substances in a graduated flask1 the volume being afterwards made up to the mark with distilled water after cooling4 ,the solution is then filtered without washing1 and by means of a pipette an aliquot part of the original volume is taken for precipitation4 ,thus all retardations in the process are avoided1 and likewise the chances of error from washing on the filter4 ,it is true that this method may lead to a certain error due to the volume of the insoluble matter which is left undecomposed1 but since this insoluble matter is usually small in quantity1 and since it is always possible to diminish the error therefrom by increasing the volume of the solution1 this cause of error is much less to be feared than those due to the difficulties which may occur in the other method4 ,let us suppose1 in order to illustrate the above1 that we are dealing with a phosphate containing fifty per cent of insoluble sand which may be considered as an extreme limit4 ,in working on four grams of the material in a flask of #ajj cubic centimeters capacity1 there will be an insoluble residue of two grams occupying a volume of about one cubic centimeter1 the density of the sand being generally nearly two4 ,the one hundred cubic centimeter flask will then contain only ninety-nine cubic centimeters of the real solution1 and the error at the most would be #j4ja4 ,this error could be reduced to one-half by dissolving only two grams of the material in place of four1 or by making the volume up to #bjj instead of #ajj cubic centimeters4 ,in general it may be said that the errors which do not exceed #j4ja of the total matter under treatment1 are negligible for all industrial products4 ,the method of volumetric solution does not present any further inconvenience4 ,it deserves to be and has been generally adopted by reason of its rapidity in all the laboratories where many analyses are to be made4 ,in the volumetric method great care should be taken not to make up to the volume until after the cooling to room temperature1 which may be speedily secured by immersing the flask in cold water4 ,care should also be exercised in taking the sample for analysis by means of the pipette immediately after filtration1 and filtration should take place as soon as the volume is made up to the standard4 ,by operating in this way the possible variations from changes of volume due to changes of temperature are avoided4 7#h7 ,examination for ,arsenic ,acid4--,when the sample examined contains pyrites1 arsenic is often present4 ,when the decomposition has been effected by means of nitric acid1 arsenic acid may be produced4 ,this deports itself in all circumstances like phosphoric acid1 and if it is present in the matter under examination it will be found united with the phosphoric acid and determined therewith afterwards4 ,it is easy to avoid this cause of error by passing first a current of sulfurous acid through the solution1 carrying it to the boiling-point in order to drive out the excess of sulfurous acid1 and afterwards precipitating the arsenic by a current of hydrogen sulfid4 ,after filtration1 the rest of the operation can be carried on as already described4 #hi4 ,precipitation of the ,phosphate by ,magnesium ,citrate4--,by means of an accurate pipette a quantity of the solution representing from #j4abe to #j4bej gram or more is taken1 according to the presumed richness of the product to be examined4 ,in order that the following operations may go on well1 it is necessary that the quantity of phosphoric acid contained in the sample should be about fifty milligrams4 ,the sample being measured is run into a beaker1 and there are added1 first1 ten cubic centimeters of magnesium citrate solution1 and second1 a large excess of ammonia4 ,if the quantity of the magnesium citrate solution be sufficient1 the mixture should at first remain perfectly limpid and only become turbid at the end of some moments and especially after the mixture is stirred4 ,if there should be an immediate turbidity produced it is proof that the quantity of magnesium citrate solution employed has been insufficient1 and it is necessary to begin again by doubling its amount4 ,good results cannot be obtained by adding a second portion of the magnesium citrate solution to the original1 since the iron and aluminum phosphates which are once formed are redissolved with difficulty4 ,many chemists at the present time abstain from using the magnesium citrate solution and replace it by a solution of citric acid and one of magnesium sulfate1 which they pour successively into the sample under examination4 ,this is a cause of grave errors which it is necessary to point out4 ,joulie has indeed recognized the fact that the precipitation of the phosphoric acid is not completed in presence of ammonium citrate except it is employed in conjunction with a sufficient excess of magnesia4 ,but the foreign matters which accompany the phosphoric acid require different quantities of ammonium citrate in order to keep them in solution1 and it is important to increase the magnesium solution at the time of increasing the citric acid in order to maintain them always in the same proportion4 ,this is easily accomplished by measuring the two solutions1 but it is much more easily done by uniting them and adding them together4 #ij4 ,the ,magnesium ,citrate ,solution4--,the formula originally proposed by ,joulie1 and modified by ,millot1 and adopted by the ,french ,association of ,chemists1 is as follows3 ,citric acid1 #djj grams2 pure magnesium carbonate1 forty grams2 caustic magnesia1 twenty grams2 distilled water1 half a liter4 ,after solution1 add enough of ammonia to render strongly alkaline1 requiring about #fjj cubic centimeters4 ,make the volume up with distilled water to one and a half liters4 ,if the solution be turbid1 it is proof that the magnesia or the carbonate employed contains some phosphoric acid which is to be separated by filtration1 and the solution can then be preserved indefinitely4 #ia4 ,time of ,subsidence4--,when the phosphoric acid is precipitated by the mixture above mentioned1 it is necessary to allow it to subside for a certain time under a bell jar in order to avoid the evaporation of the ammonia4 ,in order to give plenty of time for this subsidence1 it is well to make the precipitations in the afternoon and the filtrations the following morning4 ,there are thus secured twelve to fifteen hours of repose1 which is time amply sufficient for all cases4 #ib4 ,filtration and ,washing4--,filtration is performed easily and rapidly upon a small filter without folds placed in a funnel with a long stem of about two millimeters internal diameter4 ,placed in a series of six or eight1 they allow the filtration to take place in regular order without loss of time1 the first filter being always empty by the time the last one is filled4 ,the supernatant liquid from the precipitate should first be decanted on the filter1 avoiding the throwing of the filtrate on the filter which would greatly retard the process1 especially if it should contain a little silica1 as often happens4 ,when the clear liquid is thus decanted as completely as possible1 the rest of the precipitate is treated with water to which one-tenth of its volume of ammonia has been added1 and the washing is continued by decantation as at first1 and afterwards by washing upon the filter until the filtered solution gives no precipitate with sodium phosphate4 ,four washings are generally sufficient to attain this result4 ,if the operations which precede have been well-conducted1 the total phosphoric acid contained in the material under examination is found upon the filter-paper1 except the small portion which remains adhering to the beaker in which the precipitation has been made4 ,the determination of the phosphoric acid comprises the following operations3 ,first1 solution of the ammonium magnesium phosphate and second1 titration by means of a standard solution of uranium4 #ic4 ,solution of the ,ammonium ,magnesium ,phosphate4--,the phosphate which has been collected upon the filter is dissolved by a ten per cent solution of pure nitric acid4 ,this solution is caused to pass into the beaker in which the precipitation was made in order to dissolve the particles of phosphate which remain adherent to its sides2 and this solution is then thrown upon the filter4 ,the filtrate is then received in a flask of about #aej cubic centimeters capacity1 marked at seventy-five cubic centimeters4 ,after two or three washings with the acidulated water1 the filter itself is detached from the funnel and introduced into the vessel which contains the solution4 ,the whole of the filtrate being collected in the flask it is saturated by one-tenth ammoniacal water until a slight turbidity is produced4 ,one or two drops of dilute nitric acid are now added until the liquor becomes limpid1 and the flask is placed upon a sand-bath in order to carry the liquid to the boiling-point4 ,after ebullition there are added five cubic centimeters of acid sodium acetate in order to cause the free nitric acid to disappear and immediately the titration1 by means of a standard solution of uranium1 is undertaken4 #id4 ,acid ,sodium ,acetate4--,the acid sodium acetate is prepared as follows3 ,crystallized sodium acetate1 #ajj grams2 glacial acetic acid1 fifty cubic centimeters2 distilled water1 enough to make one liter4 #ie4 ,standard ,solution of ,uranium4--,a solution of uranium is to be prepared as follows3 ,pure uranium nitrate1 forty grams2 distilled water1 about #hjj cubic centimeters4 ,dissolve the uranium nitrate in the distilled water and add a few drops of ammonia until a slight turbidity is produced1 and then a sufficient amount of acetic acid to cause this turbidity to disappear4 ,the volume is then completed to one liter with distilled water4 ,the uranium nitrate often contains some uranium phosphate and some ferric nitrate4 ,it is important that it be freed from these foreign substances4 ,this is secured by dissolving it in distilled water and precipitating it by sodium carbonate1 which redissolves the uranium oxid and precipitates the iron phosphate and oxid4 ,the filtered liquor is saturated with nitric acid1 and the uranium oxid reprecipitated by ammonia4 ,it is then washed with distilled water by decantation and redissolved in nitric acid1 as exactly as possible1 evaporated1 and crystallized4 ,the crystals are taken up with ether1 which often leaves still a little insoluble matter4 ,the solution is filtered1 and the ether evaporated4 ,the salt which remains is perfectly pure4 ,it frequently happens when the uranium nitrate has not been properly purified that the solution prepared as has been indicated above1 deposits a light precipitate of phosphate which alters its strength and affords a cause of error4 ,only those solutions should be employed which have been prepared some days in advance1 and which have remained perfectly limpid4 ,the solution of uranium thus obtained contains uranium nitrate1 a little ammonium nitrate1 a very small quantity of uranium acetate1 some ammonium acetate1 and a little free acetic acid4 ,its sensibility is the more pronounced as the acetates present in it are less in quantity4 ,it is important1 therefore1 never to prepare the solution with uranium acetate4 #if4 ,typical ,solution of ,phosphoric ,acid4--,in order to titrate a solution of uranium1 it is necessary to have a standard solution of phosphoric acid2 that is to say1 a solution containing a precise and known quantity of that acid in a given volume4 ,this solution is prepared by means of acid ammonium phosphate1 a salt which is easily obtained pure and dry4 ,sometimes as it may contain a small quantity of neutral phosphate which modifies the relative proportions of phosphoric acid and ammonia1 and it is indispensable to have its strength verified4 ,the titer of the typical solution should be such that it requires for the precipitation of the phosphoric acid which it contains1 a volume of the solution of uranium almost exactly equal to its own1 in order that the expansions or contractions which the two liquors undergo1 by reason of changes in the temperature of the laboratory1 should be without influence upon the results4 ,the solution of uranium prepared as has been indicated above1 precipitates almost exactly five milligrams of phosphoric acid per cubic centimeter2 the typical solution of phosphoric acid is prepared with eight and one-tenth grams of acid ammonium phosphate pure and dry1 which is dissolved in a sufficient quantity of distilled water to make one liter4 ,the acid ammonium phosphate containing #fa4gd per cent of anhydrous phosphoric acid1 the quantity above gives exactly five grams of that acid in a liter1 or five milligrams in a cubic centimeter4 #ig4 ,verification of the ,strength of the ,standard ,solution of ,phosphoric ,acid4--,the strength of the standard solution of phosphoric acid is verified by evaporating a known volume1 fifty cubic centimeters for example1 with a solution of ferric hydroxid containing a known quantity of ferric oxid4 ,the mass having been evaporated to dryness1 and ignited in a platinum crucible1 gives an increase in the weight of the iron oxid exactly equal to the amount of anhydrous phosphoric acid contained therein1 both the nitric acid and ammonia being driven off by the heat4 ,to prepare the solution of ferric hydroxid1 dissolve twenty grams of iron filings in hydrochloric acid4 ,the solution is filtered to separate the carbon1 and it is converted into ferric nitrate by nitric acid1 and the solution diluted with distilled water1 and the ferric oxid precipitated by a slight excess of ammonia4 ,the precipitate1 washed by decantation with distilled water until the wash-water no longer gives a precipitate with silver nitrate1 is redissolved in nitric acid1 and the solution is concentrated or diluted1 as the case may be1 to bring the volume to one liter4 ,in order to determine the quantity of ferric oxid which it contains1 fifty cubic centimeters are evaporated to dryness1 ignited1 and weighed4 ,a second operation like the above is carried on by adding fifty cubic centimeters of the standard solution of phosphoric acid1 and the strength of the solution thus obtained is marked upon the flask4 ,if the operation have been properly carried on1 three or four duplicates will give exactly the same figures4 ,if there are sensible differences1 the whole operation should be done over from the first4 #ih4 ,titration of the ,solution of ,uranium4--,in a #aej cubic centimeter flask marked at seventy-five cubic centimeters1 are poured ten cubic centimeters of the standard solution of phosphoric acid measured with an exact pipette2 five cubic centimeters of the acid sodium acetate are added1 and distilled water enough to make about thirty cubic centimeters1 and the whole carried to the boiling-point4 ,the titration is then carried on by allowing the solution of uranium to fall into the flask from a graduated burette1 thoroughly shaking after each addition of the uranium1 and trying a drop of the liquor with an equal quantity of a ten per cent solution of potassium ferrocyanid upon a greased white plate4 ,since the quantity of the uranium solution present will be very nearly ten cubic centimeters at first1 nine cubic centimeters can be run in without testing4 ,afterwards1 the operation is continued by adding two or three drops at a time until the test upon the white plate with the potassium ferrocyanid shows the end of the reaction4 ,when there is observed in the final test a slight change of tint1 the flask is filled up to the mark with boiling distilled water and the process tried anew4 ,if in the first part of the operation the point of saturation have not been passed1 it is still usually necessary to add a drop or two of the uranium solution in order to produce the characteristic reddish coloration1 and this increase is rendered necessary by the increase in the volume of the liquid4 ,proceeding in this manner two or three times allows the attainment of extreme precision1 inasmuch as the analyst knows just when to look for the point of saturation4 ,correction4--,the result of the preceding operation is not absolutely exact4 ,it is evident indeed that in addition to the quantity of uranium necessary for the exact precipitation of the phosphoric acid1 it has been necessary to add an excess sufficient to produce the reaction upon the potassium ferrocyanid4 ,this excess is rendered constant by the precaution of operating always upon the same volume2 namely1 seventy-five cubic centimeters4 ,it can be determined then once for all by making a blank determination under the same conditions but without using the phosphoric acid4 ,the result of this determination is that it renders possible the correction which it is necessary to make by subtracting the quantity used in the blank titration from the preceding result in order to obtain the exact strength of the uranium solution4 ,the operation is carried on as follows3 ,in a flat-bottomed flask of about #aej cubic centimeters capacity and marked at seventy-five cubic centimeters1 by means of a pipette1 are placed five cubic centimeters of the solution of sodium acetate2 some hot distilled water is added until the flask is filled to the mark1 and it is then placed upon a sand-bath and heated to the boiling-point4 ,it is taken from the fire1 the volume made up to seventy-five cubic centimeters with a little hot distilled water1 and one or two drops of the solution of uranium are allowed to flow into the flask from a graduated burette previously filled exactly to zero4 ,after each drop of the solution of uranium the flask is shaken and the liquid tried upon a drop of potassium ferrocyanid1 as has been previously indicated4 ,for a skilled eye1 four to six drops are generally necessary to obtain the characteristic coloration2 that is from two-tenths to three-tenths of a cubic centimeter4 ,beginners often use from five-tenths to six-tenths1 and sometimes even more4 ,the sole important point is to arrest the operation as soon as the reddish tint is surely seen1 for afterwards the intensity of the coloration does not increase proportionally to the quantity of liquor employed4 ,it is well to note that at the end of some time the coloration becomes more intense than at the moment when the solutions are mixed1 so that care must be taken not to pass the saturation-point4 ,this slowness of the reaction is the more marked as there is more sodium or ammonium acetate in the standard solutions4 ,this is the reason that it is important to introduce always the same quantity2 namely1 five cubic centimeters4 ,this is also the reason why the uranium acetate should not be employed in preparing the standard solution of uranium which ought to contain the least possible amount of acetate in order that the necessary quantity which is carried into each test should be as small as possible and remain without appreciable influence4 ,if it were otherwise1 the sensibility of the reaction would be diminished in proportion as a larger quantity of uranium solution was employed1 giving rise to errors which would be as much more important as the quantities of phosphoric acid to be determined were greater4 ,the correction for the uranium solution having been determined it is written upon the label of the bottle containing it4 ,causes of ,errors4--,in the work which has just been described1 some causes of error may occur to which the attention of analysts should be called4 ,the first is the error which may arise from the consumption of the small quantity of uranium phosphate which is taken with a stirring rod when the liquid is tested with potassium ferrocyanid4 ,it is very easy to be assured that the end of the reaction has really been reached4 ,for this purpose it is only necessary to note the quantity of the solution already employed and to add to it afterwards four drops2 shake1 and make a new test with a drop of the potassium ferrocyanid placed near the spot which the last one occupied4 ,if a decidedly reddish tint does not appear at the moment of removing the glass rod1 it is to be concluded that the first appearance was an illusion1 and the addition of uranium is to be continued4 ,if1 on the contrary1 the coloration appear of a decided tint1 the preceding number may be taken for exact4 ,it is then always beneficial to close the titration by this test of four supplementary drops which will exaggerate the coloration and confirm the figure found4 ,the second cause of error1 and one moreover which is the most frequently met with1 consists in passing the end of the reaction by adding the uranium too rapidly4 ,in place of giving then a coloration scarcely perceptible1 the test with the drop of potassium ferrocyanid gives a very marked coloration4 ,in this case the analysis can still be saved4 ,for this purpose the analyst has1 at his disposal1 a tenth normal solution prepared with #ajj cubic centimeters of the standard solution of phosphoric acid diluted to one liter with distilled water4 ,ten cubic centimeters of this tenth normal solution are added1 and the titration continued4 ,at the end1 the amount of additional phosphoric acid used is subtracted from the total4 ,a third cause of error is found in the foam which is often found in the liquid1 due to the shaking4 ,this foam may retain a portion of the last drops of the solution of uranium which fall upon its surface and prevent its mixture with the rest of the liquid4 ,if the glass stirring rod in being removed from the vessel pass through this froth charged with uranium1 the characteristic coloration is obtained before real saturation is reached4 ,consequently it is necessary to avoid1 as much as possible1 the formation of the foam1 and especially to take care never to take the drop for test after agitation except in the middle of the liquid where the foam does not exist4 ,suppose the titration has been made upon ten cubic centimeters of the normal solution of phosphoric acid in the conditions which we have just indicated1 and the figure for the uranium obtained is #aj4b cubic centimeters2 if now the correction1 which may be supposed to amount to two-tenths cubic centimeter1 be subtracted there will remain ten cubic centimeters of the uranium solution which would have precipitated exactly fifty milligrams of phosphoric acid4 ,the quantity of phosphoric acid which precipitates one cubic centimeter of the solution will be consequently expressed by the proportion _/ five milligrams1 which is exactly the strength required4 ,in the example which has just been given1 the inscription upon the flask holding the standard solution would be as follows3 ,solution of uranium1 one cubic centimeter equals five milligrams of phosphorus pentoxid2 correction1 two-tenths cubic centimeter4 #ii4 ,titration of the ,sample4--,the strength of the solution of uranium having been exactly determined1 by means of this solution the strength of the sample in which the phosphoric acid has been previously prepared as ammonium magnesium phosphate is ascertained4 ,in this case the quantity of phosphoric acid being unknown1 it is necessary to proceed slowly and to duplicate the tests in order not to pass beyond the point of saturation4 ,from this there necessarily results a certain error in consequence of the removal of quite a number of drops of the solution of the sample before the saturation is complete4 ,it is therefore necessary to make a second determination in which there is at once added almost the quantity of the solution of uranium determined by the first analysis4 ,afterwards the analysis is finished by additions of very small quantities of uranium until saturation is reached4 ,suppose1 for instance1 that the sample was that of a mineral phosphate1 five grams of which were dissolved in #ajj cubic centimeters1 and of which ten cubic centimeters of the solution prepared as above required #ae4c cubic centimeters of the standard solution of uranium4 ,we then would have the following data3 ,mineral phosphate1 five grams of the material dissolved in twenty cubic centimeters of hydrochloric acid4 ,water1 sufficient quantity to make #ajj cubic centimeters4 ,quantity taken1 ten cubic centimeters #j4ej gram of the sample taken4 ,solution of uranium required #ae4c cubic centimeters4 ,correction #j4b 8 8 ---- ,actual quantity of uranium solution #ae4a 8 8 ,strength of the solution of uranium1 one cubic centimeter fivemilligrams ,p,o4 ,then ,p,o in #j4ej gram of the material #e #ae4a #ge4ej milligrams4 7#ge4e x #ajj7 ,then the per cent of ,p,o ----------- #ae4aj4 #ej ,the sample under examination ought always to be prepared in duplicate1 either by making a single precipitation and re-solution of the ammonium magnesium phosphate which is made up to a certain volume and an aliquot portion of which is taken for the analysis1 or by making two precipitations under the conditions previously described4 ,when the content of phosphoric acid in the material under examination is very nearly known1 the double operation may be avoided1 especially if it be required to have rapid and only approximate analyses1 such as those which are made for general control and for the conduct of manufacturing operations4 ,but when analyses are to be used to serve as the basis of a law or for the control of a market1 they should always be made in duplicate1 and the results ought not to be accepted when the numbers obtained are widely different1 since the agreement of the two numbers will show that the work has been well executed4 ,this method of analysis1 much longer to describe than to execute1 gives results perfectly exact and always concordant when it is well carried out1 provided that the standard solutions1 upon which it rests for its accuracy1 are correctly prepared and frequently verified in the manner indicated4 ,the strength of the solution of uranium ought to be verified every three or four days4 ,the strength of the standard solution of phosphoric acid should be verified each time that the temperature of the laboratory undergoes any important change4 ,a solution prepared1 for example1 in winter when the temperature of the laboratory is from #ae to #ah would no longer be exact in summer when the temperature reaches #bh or #cj4 #ajj4 ,condition of ,phosphoric ,acid in ,superphosphates4--,superphosphates are the products of the decomposition of phosphates by sulfuric or hydrochloric acid4 ,they contain phosphoric acid combined with water1 with lime1 with magnesia1 and with iron and alumina in various proportions4 ,these combinations may be classed in three categories3 ,first1 those compounds soluble in water2 second1 those insoluble in water1 but very soluble in ammoniacal salts of the organic acids such as the citrate and oxalate2 and third1 phosphates not soluble in any of the above-named reagents4 ,in the products soluble in water are met free phosphoric acid1 monocalcium phosphate1 acid magnesium phosphate1 and the iron and aluminum phosphates dissolved in the excess of phosphoric acid4 ,in the products insoluble in water but soluble in the ammonium citrate are found bicalcium phosphate and iron and aluminum phosphates1 which together constitute the phosphates called reverted4 ,these compounds reduced to a very fine state of division in the process of manufacture are considered to contain phosphoric acid of the same economic value4 #aja4 ,determination of the ,total ,phosphoric ,acid in ,superphosphates and ,fertilizers4--,the process is carried on exactly as for an ordinary phosphate1 and with all the care indicated in connection with the sampling1 the incineration1 the solution by means of hydrochloric acid1 and the separation of the phosphoric acid in the state of ammonium magnesium phosphate1 and finally in the titration by uranium4 #ajb4 ,determination of ,soluble and ,reverted ,phosphoric ,acid4--,to make this determination a method unique and applicable to all cases consists in extracting1 at first1 the soluble constituents in distilled water1 and following this operation by digestion in the ammonium citrate4 ,the products soluble in water can be determined either separately or at the same time as the products soluble in the ammonium citrate according to the taste of the people interested1 without its being necessary to modify very greatly the method of operation4 ,the determination of the soluble phosphoric acid comprises first1 the solution of the soluble constituents in distilled water2 second1 the solution of the reverted phosphates in ammonium citrate2 third1 the precipitation of the phosphoric acid dissolved in the two preceding operations1 and its determination4 #ajc4 ,preparation of the ,sample for ,analysis4--,the sample sent to the chemical expert is prepared as has been indicated2 that is to say1 it is poured on a sieve of which the meshes have a diameter of one millimeter1 and sifted upon a sheet of white paper4 ,the parts which do not pass the sieve are broken up either by the hand or in a mortar and added1 through the sieve1 to the first portions4 ,the product is well mixed and1 in this state1 the mass presents all the homogeneity desirable for analysis4 ,some fertilizers are received in a pasty state which does not permit of their being sifted4 ,it is necessary in such a case to mix them with their own weight either of precipitated calcium sulfate dried at #afj or with fine sand washed with hydrochloric acid and dried1 which divides the particles perfectly and permits of their being passed through the meshes of the sieve4 #ajd4 ,extraction of the ,products ,soluble in ,distilled ,water4--,the substance having been prepared as has just been indicated1 one and a half grams are placed in a glass mortar4 ,twenty cubic centimeters of distilled water are added1 and the substance gently suspended therein4 ,after standing for one minute1 the supernatant part is decanted into a small funnel provided with a filter-paper and placed in a flask marked at #aej cubic centimeters4 ,this operation is repeated five times and is terminated by an intimate breaking up of the matter with distilled water4 ,when the volume of #ajj cubic centimeters of the filtrate has been obtained1 the residue in the mortar is placed on the filter1 and the washing is continued until the total volume reaches #aej cubic centimeters4 ,the filtrate is shaken in order to render the liquor homogeneous1 and is transferred to a precipitating glass of about #cjj cubic centimeters capacity4 #aje4 ,solution of the ,reverted ,phosphates by ,ammonium ,citrate4--,the filter from the above process is detached from the funnel and is introduced into a flask marked at #aej cubic centimeters together with sixty cubic centimeters of alkaline ammonium citrate prepared in the following manner3 ,pure citric acid1 #djj grams4 ,ammonia of #bb1 #ejj cubic centimeters4 ,the ammonia is poured upon the citric acid in the form of crystals in a large dish4 ,the mass becomes heated1 and the solution takes place rapidly4 ,when it is complete and the solution is cold it is poured into a flask of one liter capacity1 and the flask is filled up to the mark with strong ammonia4 ,it is preserved for use in a well-stoppered bottle4 ,the solution must be strongly alkaline4 ,the flask in which the filter-paper is introduced1 together with the ammonium citrate1 is stoppered and shaken violently in order to disintegrate the filter-paper and put the reverted phosphates in suspension4 ,there are added then about sixty cubic centimeters of distilled water1 and the flask is shaken and left for twelve hours at least1 or at most for twenty-four hours4 ,the volume is made up to #aej cubic centimeters with distilled water1 and1 after mixture1 the solution is filtered4 ,there are thus obtained two solutions which can be precipitated together or separately according to circumstances4 ,the most usual process is to combine the two equal volumes of twenty-five1 fifty1 or one hundred cubic centimeters1 representing one-quarter1 one-half1 or one gram of the material according to its presumed richness1 in a precipitating flask to which are added from ten to twenty cubic centimeters of the solution of magnesia made up as follows3 ,magnesium carbonate1 #ej grams4 ,ammonium chlorid1 #ajj 8 ,water1 #ejj cubic centimeters4 ,hydrochloric acid1 #abj 8 8 ,after complete solution of the solid matters in the above1 add #ajj cubic centimeters of ammonia of #bb strength1 and distilled water enough to make one liter4 ,the solutions are thoroughly mixed in a precipitating glass1 an excess of ammonia added1 and allowed to stand for twelve hours under a bell jar4 ,the phosphoric acid contained in the liquor is separated as ammonium magnesium phosphate4 ,it is collected upon a small filter1 washed with a little ammoniacal water1 redissolved1 and titrated with the uranium solution in the manner already indicated4 ,example3 ,the following is an example of this kind of a determination3 7#a7 ,one and one-half grams of the superphosphate and distilled water enough to make #aej cubic centimeters4 7#b7 ,filter-paper with reverted phosphates1 sixty cubic centimeters of ammonium citrate1 and a sufficient quantity of distilled water to make #aej cubic centimeters4 ,aqueous solution 7#a7 #be cc #j4be grams of the sample4 ,citrate solution 7#b7 #be cc ,add magnesium solution twenty cubic centimeters and ammonia in excess1 and allow from twelve to twenty-four hours of digestion1 then filter and wash1 dissolve and titrate4 ,required of solution of uranium #h4ee cubic centimeters 7#a cubic centimeter #e milligrams ,p,o74 ,correction #j4bj4 ,remainder #h4ce #j4jje #j4jdage gram ,p,o for #j4be gram of the sample4 ,then #j4jdage #j4be #af4g per cent4 ,from the above data there would be #af4g per cent of phosphoric acid soluble in water and in ammonium citrate4 ,if it be desirable to have separately the phosphoric acid soluble in water1 a separate precipitation is made of the aqueous solution alone by means of the magnesium citrate solution4 ,the precipitate washed with ammoniacal water is redissolved and titrated in the manner indicated4 ,in subtracting from the figures obtained with the two solutions together the number obtained for the phosphoric acid soluble in water1 the number representing the phosphoric acid soluble in ammonium citrate alone1 is obtained4 ,it is to be noted that the determinations with uranium require always two successive titrations4 ,it would therefore be an advantage in all operations to precipitate a weight of ammonium magnesium phosphate sufficient for allowing this precipitate to be dissolved and made up to #ajj cubic centimeters on which amount it would be possible to execute two1 three1 or four determinations1 and thus to obtain a figure absolutely incontestable4 #ajf4 ,conclusions4--,it has been seen from the above data that the ,french chemists have worked out the uranium volumetric method with great patience and attention to detail4 ,where many determinations are to be made it is undoubtedly possible for an analyst to reach a high degree of accuracy as well as to attain a desirable rapidity1 by using this method4 ,for a few determinations1 however1 the labor of preparing and setting the standard solutions required would be far greater than the actual determinations either by the molybdate or citrate gravimetric methods4 ,for control work in factories and for routine work connected with fertilizer inspection1 the method has sufficient merit to justify a comparison with the processes already in use by the official chemists of this country4 ,the use of an alkaline ammoniacal citrate solution1 however1 for the determination of reverted acid renders any comparison of the ,french method with our own impossible4 ,on the other hand the ,french method for water-soluble acid is based on the same principle as our own2 viz41 washing at first with successive small portions of water1 and thus avoiding the decomposition of the soluble phosphates1 which is1 likely to occur when too great a volume of water is added at once4 ,in the matter of the temperature and time as affecting the solubility of reverted acid1 the ,french method is also distinctly inferior to our own4 ,the digestion is allowed to continue from twelve to twenty-four hours1 at the pleasure of the analyst1 and meanwhile it is subjected to room temperature4 ,it is not difficult to see that this treatment in the same sample would easily yield disagreeing results between twelve hours at a winter temperature and twenty-four hours at summer heat4 ,,the ,,determination ,,of ,,phosphoric ,,acid ,,by ,,titration ,,of ,,the ,,yellow ,,precipitate4 #ajg4 ,pemberton's ,volumetric ,method4--,in order to shorten the work of determining the phosphoric acid1 numerous attempts have been made to execute the final determination directly on the yellow precipitate obtained by treating a solution of a phosphate with ammonium molybdate in nitric acid4 ,the composition of this precipitate appears to be somewhat variable1 and this fact has cast doubt on the methods of determination based on its weight4 ,its most probable composition is expressed by the following formula1 7,,nh7,,po7,mo,o74 ,for convenience in writing reactions this formula should usually be doubled4 ,pemberton has described a volumetric determination of phosphoric acid in the yellow precipitate which has the merit of being rapid4#hc ,in this laboratory the method has not given very satisfactory results when compared with the molybdate gravimetric process4 ,it has however attracted so much attention from analysts as to merit description1 and the details of the process are therefore given4 #ajh4 ,the ,process4--,one gram of phosphate rock1 or from two to three grams of phosphatic fertilizer1 are dissolved in nitric acid1 and1 without evaporation1 diluted to #bej cubic centimeters4 ,without filtering1 twenty-five cubic centimeters are placed in a four-ounce beaker and ammonia added until a slight precipitate begins to form4 ,five cubic centimeters of nitric acid of one and four-tenths specific gravity are then added1 and afterwards ten cubic centimeters of saturated solution of ammonium nitrate and enough water to make the volume about sixty-five cubic centimeters4 ,the contents of the beaker are boiled1 and while still hot1 five cubic centimeters of the aqueous solution of ammonium molybdate added4 ,additional quantities of the molybdate are added1 if necessary1 until the whole of the phosphorus pentoxid is thrown-out4 ,after allowing to settle for a moment the contents of the beaker are poured upon a filter seven centimeters in diameter4 ,the precipitate is thoroughly washed with water1 both by decantation and on the filter4 ,the filter with its precipitate is transferred to a beaker and titrated with standard alkali1 in the presence of phenolphthalein4 ,each cubic centimeter of alkali employed should correspond to one milligram of phosphorus pentoxid1 7,p,o74 ,the reagents employed have the composition indicated below3 ,ammonium ,molybdate4--,ninety grams of the crystals of ammonium molybdate are placed in a large beaker and dissolved in a little less than one liter of water4 ,the beaker is allowed to stand over night and the clear liquor decanted4 ,any undissolved acid is brought into solution in a little ammonia water and added to the clear liquor4 ,if a trace of phosphoric acid be present a little magnesium sulfate is added and enough ammonia to produce a slight alkaline reaction4 ,the volume of the solution is then made up to one liter4 ,each cubic centimeter of this solution is capable of precipitating three milligrams of phosphorus pentoxid4 ,standard ,potassium ,hydroxid4--,this solution is made of such strength that one cubic centimeter is equivalent to one milligram of phosphorus pentoxid4 ,treated with acid of normal strength1 #ajj cubic centimeters are required to neutralize #cb4cg cubic centimeters thereof4 ,standard ,acid4--,this should have the same strength1 volume for volume1 as the standard alkali solution4 ,it is made by diluting #cbc4g cubic centimeters of normal acid to one liter4 ,indicator4--,the indicator to be used is an alcoholic solution of phenolphthalein1 one gram in #ajj cubic centimeters of sixty per cent alcohol1 and half a cubic centimeter of this should be used for each titration4 ,thomson has shown#hd that of the three hydrogen atoms in phosphoric acid two must be saturated with alkali before the reaction with phenolphthalein is neutral4 ,therefore1 when the yellow precipitate is broken up by an alkali1 according to the reaction to follow1 only four of the six molecules of ammonium are required to form a neutral ammonium phosphate as determined by the indicator employed4 ,the remaining two molecules of ammonium unite with the molybdenum forming also a salt neutral to the indicator4 ,phenolphthalein is preferred because1 as has been shown by ,long1 its results are reliable in the presence of ammonium salts unless they be present in large quantity1 and if the solution be cold and the indicator be used in sufficient quantity4#he ,to prepare the indicator for this work1 one gram of phenolphthalein is dissolved in #ajj cubic centimeters of sixty percent alcohol4 ,at least one-half of a cubic centimeter of the solution is used for each titration4 ,the advantages claimed for the method are its speed and accuracy4 ,much time is saved by avoiding the necessity for the removal of the silica by evaporation4 ,the results of analyses with and without the removal of the silica are practically identical4 ,when the silica is not removed it is noticed that the filtrate from the yellow precipitate has a yellow tint4 ,the reaction is represented by the following formula3 7,,nh77,,po77,mo,o7 #df,,koh 7,,nh77,,hpo7 7,,nh7,mo,o #bc,k,mo,o #bb;,h,o4 ,from this reaction it is seen that the total available acidity of one molecule of the yellow precipitate titrated against phenolphthalein is equivalent to twenty-three molecules of potassium hydroxid4 ,calculation of ,results4--,the standard alkali is of such strength that one cubic centimeter is equal to one per cent of phosphoric acid when one gram of material is employed and one-tenth of it taken for each determination4 ,in a given case one gram of a sample was taken and one-tenth of the solution used4 ,fifty cubic centimeters of alkali were added to the yellow precipitate4 ,it required thirty-two cubic centimeters of standard alkali to neutralize the excess4 ,the alkali consumed by the yellow precipitate was #ej - #cb #ah4 ,the sample therefore contained eighteen per cent of phosphoric acid4 ,comparison with ,official ,method4--,a comparison of the ,pemberton volumetric with the official method of the ,association of ,agricultural ,chemists has been made by ,day and ,bryant4#hf ,the comparisons were made on samples containing from #a4de to #cg4bh per cent of phosphoric acid and resulted as follows3 ,per cent ,per cent ,p,o1 ,p,o1 ,substance4 ,official4 ,pemberton4 ,no4 #a4 ,florida rock #a4de #a4cb 8 #b4 8 8 #d4dj #d4ec 8 #c4 ,sodium phosphate #ai4gh #ai4ii 8 #d4 8 8 #ai4gb #ai4gc 8 #e4 ,florida rock #cg4bh #cg4bb ,this near agreement shows the reliability of the method4 ,the comparison of the ,pemberton volumetric method with the official gravimetric method was investigated by the reporter of the ,association of ,official ,agricultural ,chemists in #ahid4hg ,the individual variations were found to be greater than in the regular method but the average results were nearly identical therewith4 ,the method works far better with small percentages of phosphoric acid than with large4 ,where the average of the results by the official methods gave #ab4be per cent1 the volumetric process gave #aa4ij per cent1 whereas in the determination of a smaller percentage the results were #b4gb and #b4gc per cent1 respectively4 ,kilgore proposes a variation of the method which differs from the original in two principal points4#hh ,first the temperature of precipitation in the ,pemberton process is #ajj2 but in the modified form from #ee to #fj4 ,at the higher temperature there is danger of depositing molybdic acid4 ,the second difference is in the composition of the molybdate solution employed4 ,the official molybdate solution contains about sixty grams of molybdenum trioxid in a liter while the ,pemberton solution contains sixty-six grams4 ,there is therefore not much difference in strength4 ,the absence of nitric acid1 however1 from the ,pemberton solution favors the deposition of the molybdic acid when heat is applied4 ,kilgore1 therefore1 conducts the analysis as follows3 ,the solution of the sample is made according to the official nitric and hydrochloric acid method for total phosphoric acid4 ,for the determination1 twenty or forty cubic centimeters are taken1 corresponding to two-tenths or four-tenths gram of the sample4 ,ammonia is added until a slight precipitate is produced and the volume is then made up1 with water1 to seventy-five cubic centimeters4 ,add some ammonium nitrate solution1 from ten to fifteen cubic centimeters1 but this addition is not necessary unless much of the nitric acid has been driven off during solution4 ,heat in water-bath to #fj and precipitate with some freshly filtered official molybdate solution4 ,allow to stand for five minutes1 filter as quickly as possible1 wash four times by decantation using from fifty to seventy-five cubic centimeters of water each time1 and then wash on a filter until all acid is removed4 ,the solution and titration of the yellow precipitate are accomplished as in the ,pemberton method4 ,the agreement of the results obtained by this modified method was much closer with the official gravimetric method than those obtained by the ,pemberton process4 #aji4 ,estimation of ,phosphoric ,acid as a ,lead ,compound4--,in the volumetric lead method1 as described by ,wavelet1 the phosphoric acid is precipitated by the magnesium citrate solution as in the uranium method of ,joulie1 as practiced by the ,french chemists1 and the washing of the precipitate and its solution in nitric acid are also conducted as in that method4#hi ,after solution in nitric acid ammonia is added to neutrality and the solution is then made acid with acetic4 ,the phosphoric acid is precipitated in the acid solution by a standard solution of lead nitrate1 the precipitate having the formula ,p,o#c,pb,o4 ,the end reaction is determined by placing a drop of the titrated mixture on a white greased dish in contact with a drop of a five per cent solution of potassium iodid4 ,when all the phosphoric acid is precipitated the least excess of the lead salt is revealed by the characteristic yellow precipitate of lead iodid4 ,the author of the process claims that the lead phosphate is insoluble in the excess of acetic acid and that the phosphate itself does not give any yellow coloration with potassium iodid4 ,the process is quite as exact as the uranium method and the end reaction is far sharper and the standard reagents are easily made and preserved4#ij ,the method described merits1 at least1 a comparative trial with the uranium process1 but cannot be recommended as exact until further approved by experience4 ,the reagents employed have the following composition3 7#a7 ,disodium phosphate solution containing #aj4jhe grams per liter 7#b7 ,sodium acetate 8 8 #ej4jjj 8 8 8 7#c7 ,lead nitrate 8 8 #dj4jjj 8 8 8 7#d7 ,potassium iodid 8 8 #ej4jjj 8 8 8 ,the titrations should be conducted in the cold4 #aaj4 ,water-,soluble ,phosphoric ,acid4--,glaser has modified the volumetric method of ,kalmann and ,meissels for the volumetric estimation of water-soluble phosphoric acid so as to avoid the double titration required by the original method4#ia ,if methyl orange be used as an indicator in the original method1 the determination does not at once lead to the tricalcium salt1 but the liquid still contains1 after neutralization1 some monocalcium phosphate1 which is determined by a further titration with phenolphthalein4 ,in the modified method the total phosphoric acid is estimated in one operation as a tricalcium salt4 ,this is secured1 by adding1 at the proper time1 an excess of calcium chlorid4 ,two grams of the superphosphate are shaken with water several times1 and1 after settling1 filtered1 and the insoluble residue finally washed on the filter until the total volume of the filtrate is a quarter of a liter4 ,of this1 fifty cubic centimeters are taken and titrated with tenth normal soda-lye1 with addition of two drops of methyl orange1 until the acid reaction has entirely disappeared4 ,there is then added some neutral calcium chlorid solution in excess4 ,if iron and alumina be present1 a precipitate is produced of which no account need be made4 ,the acid reaction is thus restored4 ,five drops of the phenolphthalein solution are added and the titration continued until the alkaline reaction is noted throughout the whole mass4 ,each cubic centimeter of the soda-lye corresponds1 in the first titration1 to #g4a1 and in the second to #c4ee milligrams of phosphoric acid4 #aaa4 ,estimation of ,phosphoric ,acid in the ,presence of a ,large ,excess of ,iron4--,the method given below1 due to ,emmerton1 depends upon the precipitation of a phosphomolybdate1 of constant composition1 in the presence of a large excess of iron1 as in the analysis of iron and steel and iron ores4#ib ,the molybdenum trioxid obtained is reduced by zinc to ,mo,o4 ,the action of permanganate on this compound is shown in the following equation3 #e,mo,o #ag7,k,o,mn,o7 #fj,mo,o #ag,k,o #cd,mn,o4 ,seventeen molecules of permanganate are equal to sixty molecules of molybdenum trioxid4 ,the iron or steel is dissolved in nitric acid1 evaporated to dryness1 heated1 and redissolved in hydrochloric acid1 then treated again with nitric acid and evaporated until a clear and concentrated solution is obtained free from hydrochloric acid4 ,the solution obtained is diluted to forty cubic centimeters with water and washed into a #djj cubic centimeter flask1 making the total volume about seventy-five cubic centimeters4 ,add strong ammonia1 shaking after each addition1 until the mass sets to a thick jelly from the ferric hydroxid4 ,add a few more cubic centimeters of ammonia and shake thoroughly1 being sure the ammonia is present in excess4 ,add next nitric acid gradually1 with shaking1 until the precipitate has all dissolved2 add enough more nitric acid to make the solution a clear amber color4 ,the volume should now be about #bej cubic centimeters4 ,bring the solution to #he and add1 at once1 forty cubic centimeters of molybdate solution of the following strength3 ,dissolve #ajj grams of molybdic acid in #cjj cubic centimeters of strong ammonia and #ajj cubic centimeters of water1 and pour the solution into #a1bej cubic centimeters of nitric acid 7#a4bj72 close the flask with a rubber stopper1 wrap it in a thick cloth1 and shake violently for five minutes4 ,collect the precipitate on a filter1 using pump1 and wash with dilute nitric acid 7#a ,,hno3 #ej ,h,o74 ,if a thin film of the precipitate should adhere to the flask it can be removed by the ammonia in the next operation4 ,wash the molybdate precipitate into a #ejj cubic centimeter flask with dilute ammonia 7#a ,h,n3 #d ,h,o71 using about thirty cubic centimeters4 ,add hot dilute sulfuric acid 7#a ,h,,so3 #d ,h,o7 and cover the flask with a small funnel4 ,add ten grams of granulated zinc and heat until rapid action begins1 and then heat gently for five minutes4 ,the reduction is then complete4 ,during the reduction the colors1 pink1 plum1 pale green1 and dark green1 are seen in the molybdate solution1 the latter color marking the end of the reaction4 ,to remove the zinc1 pour through a large folded filter1 wash with cold water1 and fill up the filter once with cold water4 ,but little oxidation takes place in this way4 ,a port-wine color is seen on the filter1 but this does not indicate a sufficient oxidation to make an error4 ,in titrating1 the wine color becomes fainter and finally the solution is perfectly colorless and shows a single drop in excess of the permanganate4 ,the permanganate solution1 for convenience1 is made so that one cubic centimeter is equal to #j4jjja gram of phosphorus4 ,with iron its value is one cubic centimeter equals #j4jjfada gram of iron2 and one cubic centimeter equals #j4jjeegd gram of molybdenum trioxid4 #aab4 ,variation of ,dudley and ,noyes4--,the method of ,emmerton to determine small quantities of phosphoric acid1 or of phosphorus in presence of a large excess of iron1 has been modified by ,dudley and ,pease1#ic and by ,noyes and ,royse4#id ,as modified1 the method is not intended for fertilizer analysis1 but the principle on which it rests may some time1 with proper modifications1 find application in fertilizer work4 ,the reduction is accomplished in a ,jones' tube1#ie much simplified1 so as to render it suitable for common use4 ,the molybdic acid is reduced to a form1 or series of forms1 corresponding to molybdenum sesquioxid1 as in the ,emmerton method1 and subsequently as in that method1 titrated by a set solution of potassium permanganate4 ,the iron or steel filings1 containing phosphorus1 are brought into solution by means of nitric acid4 ,for this purpose two grams of them are placed in a half liter flask together with fifty cubic centimeters of nitric acid of #a4ah specific gravity4 ,the mixture is boiled for one minute1 and ten cubic centimeters of permanganate solution of one and a quarter per cent added4 ,boil again until the pink color disappears4 ,ferrous sulfate solution is next to be carefully added1 shaking meanwhile1 until the solution clears4 ,cool to #ej and add eight cubic centimeters of ammonia of #j4ij specific gravity1 stopper the flask1 and shake until any precipitate which may form is redissolved4 ,cool or warm1 as the case may be1 until the solution is as many degrees above or below #fj as the molybdic solution is above or below #bg4 ,add sixty cubic centimeters of molybdic solution1 stopper1 and shake on a machine or by hand for five minutes4 ,after remaining at rest for five minutes pour into a nine centimeter filter of fine texture and wash with the acid ammonium sulfate solution in quantities of from five to ten cubic centimeters each time4 ,the filtrate and washings must be perfectly bright4 ,continue the washings until the filtrate gives no color with hydrogen sulfid4 ,dissolve the yellow precipitate with twelve cubic centimeters of #j4if ammonia diluted with an equal volume of water1 and wash the filter with #ajj cubic centimeters of water4 ,finally add to the filtrate and wash-water eighty cubic centimeters of water and ten of strong sulfuric acid4 ,pass the mixture through the ,jones' reducing tube and follow it with #bjj cubic centimeters of water1 taking care that no air enter the tube during the operations4 ,the solution collected in the flask should be at once titrated with potassium permanganate4 ,solutions used3 7#a7 ,nitric acid4--,one part of nitric acid of #a4db specific gravity and two parts of water by volume4 ,the specific gravity of the mixture is about #a4ah4 7#b7 ,permanganate solution for oxidizing4--,dissolve #ab4e grams of potassium permanganate in one liter of water4 7#c7 ,ferrous sulfate4--,fresh crystals not effervesced and free from phosphorus4 7#d7 ,ammonia4--,the strong ammonia used should have a specific gravity of about #j4ij and the dilute of #j4if at #ae4e4 7#e7 ,molybdic ,solution4--,dissolve #ajj grams of molybdic anhydrid in #djj cubic centimeters of ammonia of #j4if specific gravity and pour the solution slowly1 with constant stirring1 into one liter of nitric acid of about #a4bj specific gravity4 ,heat the mixture to #de and add one cubic centimeter of a ten per cent solution of sodium phosphate1 stir vigorously1 and allow to stand in a warm place for eighteen hours4 ,filter before using4 7#f7 ,add ,ammonium ,sulfate4--,to half a liter of water add #bg4e cubic centimeters of #j4if ammonia and twenty-four cubic centimeters of strong sulfuric acid1 and make the volume one liter with water4 7#g7 ,potassium ,permanganate for ,titration4--,dissolve four grams of potassium permanganate in two liters of water1 heat nearly to boiling for an hour1 allow to stand for eighteen hours1 and filter on asbestos felt4 ,the solution must not come in contact with rubber or other organic matter4 ,the solution may be standardized with thoroughly air-dried ammonium oxalate in solution with a little dilute sulfuric acid and with ammonium ferrous sulfate partly crystallized in small crystals from a slightly acid solution4 ,the crystals should be well washed and quickly air-dried in a thin layer4 ,the factors #a_/a #a_/d #b_/b and #a_/g should be used respectively to calculate the iron equivalent4 ,the phosphorus equivalent is obtained by multiplying the iron equivalent by #ca 7#cf #ef7 #j4jaech4 ,illustration3 ,,figure #g4 ,,jones' ,,reduction ,,tube4 ,reduction ,apparatus4--,the reduction of the molybdic acid to molybdenum trioxid is accomplished in a tube first proposed by ,jones4 ,the apparatus is shown in ,figure #g4 ,a piece of moderately heavy glass tubing thirty-five centimeters long with an internal diameter of two centimeters is drawn out at the lower end so as to pass into the stopper of a flask4 ,a circular piece of perforated platinum or porcelain rests on the constricted portion of the tube and this is covered with an asbestos felt4 ,the tube is then nearly filled with powdered zinc which is washed1 before using1 with dilute sulfuric acid 7#a3 #bj74 ,a1 ,b1 ,c represent different methods of filtering the molybdic solution4 ,in ,a a platinum cone is placed in the constricted portion of the tube and the asbestos felt placed thereon and the tube then filled with the granulated zinc4 ,in ,b there is first inserted a perforated disk then some very fine sand and this is covered with another disk4 ,in ,c there is a perforated disk which is covered with asbestos felt4 ,the filtering arrangement should be such as to prevent any zinc particles from reaching the flask and yet permitting the filtration to go on without much difficulty4 ,a blank determination is first made by adding to #ahj cubic centimeters of water1 twelve of #j4if ammonia and ten of strong sulfuric acid4 ,this is poured through the reducing tube and followed with #bjj cubic centimeters of water taking care that no air enter the apparatus4 ,hydrogen peroxid is formed if air enter4 ,even after standing for a few moments the tube should be washed with dilute sulfuric acid before again using it4 ,the filtrate should be titrated with the permanganate solution and the amount required deducted from the following amounts obtained with the molybdic salt4 ,calculations4--,the calculations of the amount of phosphorus in a given sample of iron or steel are made according to the following data3 ,in a given case let it be supposed that the permanganate solution is set with a solution of piano wire and it is found that one cubic centimeter of permanganate liquor is equal to #j4jjcdff gram of metallic iron4 ,it is found that #ij4gf parts of molybdic acid will produce the same effect on permanganate as #ajj parts of iron4 ,hence one cubic centimeter of permanganate solution is equivalent to #j4jjcdff #j4ijgf #j4jjcade gram of molybdic acid4 ,in the yellow precipitate formed1 in the conditions named for the analysis it is found that the phosphorus is one and nine-tenths per cent of the molybdic acid present4 ,therefore one cubic centimeter of permanganate liquor is equal to #j4jjcade #j4jai #j4jjjjeig gram of phosphorus4 ,if then1 for example1 in a sample of iron or steel eight and six-tenths cubic centimeters of permanganate solution1 after correction1 be found necessary to oxidize the molybdic solution after passing through the ,jones' reducing tube1 the amount of phosphorus found is #j4jjjjeig #h4f #j4jea per cent4 #aac4 ,the ,silver ,method4--,the separation of the phosphoric acid by silver according to the method of ,perrot has been investigated by ,spencer1 who found the process unreliable4#if ,by a modification of the process1 however1 ,spencer obtained fairly satisfactory results4 ,the principle of this method depends on the separation of the phosphoric acid by silver carbonate and the subsequent titration thereof with standard uranium solution after the removal of the excess of silver4 ,the operation is conducted as follows3 ,the fertilizer is first ignited until all organic matter and residual carbon are destroyed4 ,solution is then accomplished by means of nitric acid and the volume completed to a definite quantity4 ,an aliquot part is taken1 after filtration1 varying with the supposed strength of the solution so as to contain about #ajj milligrams of phosphorus pentoxid4 ,in the slightly nitric acid solution add freshly prepared silver carbonate in excess1 that is1 sufficient to saturate any free acid present and also to combine with all the phosphoric acid4 ,wash thoroughly with hot water and then dissolve the mixed phosphate and silver carbonate in nitric acid and remove the silver from the solution with sodium chlorid4 ,the phosphoric acid is determined in the filtrate by means of a standard solution of uranium nitrate in the manner already described4 ,spencer found that the separation of the phosphoric acid by the silver method was more exact than by the ,joulie magnesium citrate process4 ,with practice on the part of the analyst in determining the end reaction the process is both rapid and accurate4 ,the method is also inexpensive1 as both the silver and uranium are easily recovered from the waste4 #aad4 ,volumetric ,silver ,method4--,holleman has proposed a modification of the silver method for the volumetric determination of phosphoric acid1 which is conducted in the following manner3#ig ,in a flask of #bjj cubic centimeters capacity1 are placed fifty cubic centimeters of the liquid to be analyzed1 which should not contain more than two-tenths gram of phosphoric acid4 ,the solution is treated with ten cubic centimeters of a normal solution of sodium acetate and afterwards with a slight excess of decinormal silver solution1 four and five-tenths cubic centimeters for each #j4ja gram of phosphoric acid4 ,the solution is then neutralized with tenth normal sodium hydroxid1 the amount required having been previously determined by titrating ten cubic centimeters of the liquid to be analyzed1 using phenolphthalein as an indicator4 ,five times the quantity required for the neutralization of the ten cubic centimeters is added1 less one-half cubic centimeter4 ,by this treatment the phosphoric acid in the presence of sodium acetate is completely precipitated as silver phosphate4 ,the excess of silver is determined by diluting the mixture to #bjj cubic centimeters1 filtering1 and titrating #ajj cubic centimeters of the filtrate with ammonium thiocyanate4 ,the presence of sulfuric and nitric acids does not interfere with the reaction1 but of course hydrochloric acid must be absent4 ,alkalies and alkaline earth metals may be present1 but not the heavy metals4 ,when iron and aluminum are present #ajj cubic centimeters of the solution are precipitated with thirty cubic centimeters of normal sodium acetate1 the phosphoric acid is determined in fifty cubic centimeters of the filtrate1 and the precipitate of iron and aluminum phosphates is ignited and weighed1 and its weight multiplied by #b4bbe is added to the phosphoric anhydrid found volumetrically4 ,if ammonia be present it must be removed by boiling1 as otherwise it affects the titration with phenolphthalein4 ,for agricultural purposes this method can have but little value inasmuch as the phosphates to be examined almost always have a certain proportion of iron and aluminum4 ,inasmuch as the amount of these bases has to be determined gravimetrically1 there would be no gain in time and no simplification of the processes by the use of the volumetric method as proposed4 ,,technical ,,determination ,,of ,,phosphoric ,,acid4 #aae4 ,desirability ,of ,methods4--,in the preceding paragraphs1 has been given a statement of the principal methods now in use by chemists and others connected with fertilizer control for the scientific and agronomic determinations of phosphoric acid1 and its agricultural value4 ,a rsum of the important methods1 in a form suited to use in a factory for preparing phosphatic fertilizers for the market1 seems desirable4 ,in these factories the chemists have been accustomed to use their own1 or private methods1 and there has not been a general disposition among them to publish their methods and experience for the common benefit4 ,for factory processes1 a method should be not only reasonably accurate1 but also simple and rapid4 ,it is evident1 therefore1 that the general principles already indicated must underlie any method which would prove useful to factory work4 ,albert has made a rsum of such methods applicable for factory control1 and these are given here for convenience1 although they are1 in many respects1 but condensed statements of methods already described4#ih #aaf4 ,reagents4--,molybdate ,solution4--,one hundred and ten grams of pure molybdic acid are dissolved in ammonia of nine-tenths specific gravity and diluted with water to one liter4 ,the solution is poured into one liter of nitric acid1 of one and two-tenths specific gravity1 and1 after standing a few days1 filtered4 ,concentrated ,ammonium ,nitrate ,solution4--,seven hundred and fifty grams of pure ammonium nitrate are dissolved in water and made up to one liter4 ,magnesia ,mixture4--,fifty-five grams of magnesium chlorid2 seventy grams of ammonium chlorid2 #acj cubic centimeters of ammonia of nine-tenths specific gravity are dissolved and diluted with water to one liter4 ,two and ,one-,half ,per ,cent ,ammonia4--,one hundred cubic centimeters of ammonia of nine-tenths specific gravity are diluted with water to one liter4 ,joulie's ,citrate ,solution4--,four hundred grams of citric acid are dissolved in ammonia of nine-tenths specific gravity and diluted to one liter with ammonia of the same strength4 ,wagner's ,citrate ,solution4--,one hundred and fifty grams of citric acid are exactly neutralized with ammonia1 then ten grams of citric acid added and diluted to one liter with water4 ,sodium ,acetate ,solution4--,one hundred grams of sodium acetate1 crystallized1 are dissolved in water1 treated with #ajj cubic centimeters of acetic acid1 and diluted to one liter with water4 ,calcium ,phosphate ,solution4--,about ten grams of dry1 pure tribasic calcium phosphate are dissolved in nitric acid and diluted with water to one liter4 ,in this solution the phosphoric acid is determined gravimetrically by the molybdate or citrate method1 and the value of the solution marked on the flask containing it4 ,titrated ,uranium ,solution4--,two hundred and fifty grams of uranium nitrate are dissolved in water1 twenty-five grams of sodium acetate added1 and the whole diluted to seven liters4 ,one cubic centimeter of this solution corresponds to about #j4jje gram of phosphorus pentoxid4 ,in order to determine its exact value proceed as follows3 ,twenty-five cubic centimeters of the calcium phosphate solution which1 for example1 has been found to contain #j4ajcag gram of phosphorus pentoxid1 are neutralized in a porcelain dish with ammonia1 acidified with acetic1 treated with ten cubic centimeters of sodium acetate solution1 and warmed4 ,through a burette as much uranium solution is allowed to flow as is necessary to show in a drop of the solution taken out of the dish1 when treated with a drop of pure potassium ferrocyanid1 a slight brown color4 ,in order to be certain1 this operation is repeated two or three times with new quantities of twenty-five cubic centimeters of calcium phosphate solution4 ,example3 ,twenty-five cubic centimeters of the calcium phosphate solution containing #j4ajcag gram of phosphorus pentoxid1 gave as a mean of three determinations #bc4b cubic centimeters of the uranium solution necessary to produce the brown color with potassium ferrocyanid4 ,consequently #j4ajcag #bc4b #j4jjdde gram of phosphorus pentoxid equivalent to one cubic centimeter of uranium solution4 ,if1 for instance1 a quantity of fertilizer weighing exactly five grams1 require ten cubic centimeters of the uranium solution for the complete precipitation of its phosphoric acid1 then the quantity of phosphoric acid contained in the fertilizer would be equivalent to #aj #j4jjde1 equivalent to #j4jdde gram of phosphorus pentoxid4 ,the fertilizer1 therefore1 contains eight and nine-tenths per cent of phosphorus pentoxid4 ,conduct of the ,molybdenum ,method4--,this method rests upon the precipitation of the phosphorus pentoxid by a solution of ammonium molybdate in nitric acid1 solution of the precipitate in ammonia1 and subsequent precipitation with magnesia4 ,manipulation4--,twenty-five or fifty cubic centimeters of a solution of the phosphate which has been made up to a standard volume and containing about one-tenth gram of phosphorus pentoxid1 are placed in a beaker together with #ajj cubic centimeters of the molybdate solution and treated with as much ammonium nitrate solution as will be sufficient to give the liquid a content of fifteen per cent of ammonium nitrate4 ,the contents of the beaker are well mixed and warmed for about twenty minutes at from #fj to #hj4 ,after cooling1 they are filtered and the precipitate washed on the filter with cold water until a drop of the filtrate saturated with ammonia does not become opaque on treatment with ammonium oxalate4 ,the filtrate is then washed from the filter with two and one-half per cent ammonia solution and precipitated slowly and with constant stirring by the magnesia mixture4 ,after standing for two hours the ammonium magnesium phosphate is separated by filtration1 washed with two and one-half per cent ammonia until the filtrate contains no more chlorin1 and ignited4 ,conduct of the ,citrate ,method4--,the principle of this method depends upon the fact that when a sufficient quantity of ammonium citrate is added to phosphate solutions1 iron1 alumina1 and lime are retained in solution when1 on the addition of the magnesia mixture in the presence of free ammonia1 the phosphoric acid is completely precipitated as ammonium magnesium phosphate4 ,manipulation4--,from ten to fifty cubic centimeters of the solution of the phosphate to be determined are treated with fifteen cubic centimeters of the ,joulie citrate solution avoiding warming4 ,a few pieces of filter-paper1 the ash content of which is known1 are thrown in and1 with stirring1 fifteen cubic centimeters of magnesia mixture slowly added and if necessary also some free ammonia4 ,by the small pieces of filter-paper the collection of the precipitate against the sides of the vessel and on the stirring rod is prevented and in this way the production of the precipitate hastened4 ,after standing from one-half an hour to two hours the mixture is filtered1 ignited1 and weighed4 ,if it be preferred to estimate the phosphoric acid by titration1 the precipitate is dissolved in a little nitric acid1 made slightly alkaline with ammonia1 and then acid with acetic and then afterwards titrated with the standard uranium solution4 ,conduct of the ,uranium ,method4--,the principle upon which this method rests depends upon the fact that uranium nitrate or acetate precipitates uranium phosphate from solutions containing phosphoric acid and which contain no other free acid except acetic4 ,in the presence of ammonium salts the precipitate is uranium ammonium phosphate having the formula ,,po,,nh,ur,o4 ,the smallest excess of soluble uranium salt is at once detected by the ordinary treatment with potassium ferrocyanid4 ,manipulation4--,in all cases the solution is first made slightly alkaline with ammonia and then acid by a few drops of acetic1 so that no free mineral acid may be present4 7#a7 ,with liquids free from iron3 ,if1 on the addition of ammonium or sodium acetate1 no turbidity be produced1 the liquid is free from iron and alumina4 ,in this case from ten to fifty cubic centimeters of the solution containing about one-tenth gram of phosphorus pentoxid are treated with ten cubic centimeters of sodium acetate1 and afterwards with a quantity of uranium solution corresponding1 as nearly as possible1 to its supposed content of phosphorus pentoxid1 and heated to boiling4 ,from the heated liquid by means of a glass rod1 one or two drops are taken and placed upon a porcelain plate and one drop of a freshly prepared solution of potassium ferrocyanid allowed to flow on it4 ,if no brown color be seen at the point of contact of the two drops1 additional quantities of the uranium solution are added and1 after boiling1 again tested with potassium ferrocyanid until a brown color is distinctly visible4 ,the quantity of the uranium solution thus having been determined1 duplicate analyses can be made and the whole quantity of the uranium solution added at once with the exception of the last drops1 which are added as before4 7#b7 ,solutions containing iron and alumina4 ,the solution is treated with the ammonium citrate solution of ,joulie1 the magnesia mixture added slowly1 and the precipitate collected on a filter and washed with two and one-half per cent ammonia4 ,the precipitate is then dissolved in nitric acid1 made alkaline with ammonia1 and then acid with acetic4 ,this solution is then treated with ten cubic centimeters of sodium acetate and titrated with uranium1 as described in 7#a74 ,as an alternative method1 #bjj cubic centimeters of the superphosphate solution may be treated with fifty cubic centimeters of sodium acetate1 allowed to stand for some time1 and filtered through a filter of known ash content4 ,in fifty cubic centimeters of the filtrate1 which correspond to forty cubic centimeters of the original solution1 phosphoric acid may be determined as described above4 ,the precipitate1 consisting of iron and aluminum phosphates1 is washed three times on the filter with boiling water1 dried1 and ignited in a platinum dish4 ,the weight of ignited precipitate1 diminished by the weight of the ash contained in the filter and divided by two1 gives the quantity of phosphorus pentoxid which it is necessary to add to that obtained by titration4 #aag4 ,determination of the ,phosphoric ,acid in all ,phosphates and ,basic ,slags4-- 7#a7 ,total phosphoric ,acid3 ,five grams of the fine phosphate meal1 or slag meal1 are moistened in a flask of #ejj cubic centimeters content with some water and boiled on a sand-bath with forty cubic centimeters of hydrochloric acid of from #af to #bj ,beaum4 ,the boiling is continued until only a few cubic centimeters of a thick jelly of silicic acid remain4 ,after cooling1 some water is added and the phosphate shaken until the thick lumps of silica are finely divided4 ,the flask is then filled to #ejj cubic centimeters and its contents filtered4 ,fifty cubic centimeters of the filtrate are treated with fifteen cubic centimeters of the ,joulie solution and treated in the manner described with magnesia mixture1 precipitated1 ignited1 and weighed4 ,the precipitate can also be dissolved and treated with uranium solution as described4 ,the method used by ,oliveri may also be employed and it is carried out as indicated in the following description3#ii ,a weighed quantity of the slag is reduced to a fine powder4 ,to five grams of the sample is added three times its weight of potassium chlorate and the whole is intimately mixed4 ,the mixture is then placed in a porcelain dish and hydrochloric acid is added1 little by little1 until the potash salt is completely decomposed4 ,it is evaporated until the mass is dry4 ,the material is then treated with fuming nitric acid1 and the determination of the phosphorus is made by the ordinary gravimetric method4 ,by carrying on the operation as described above1 a reduction of phosphoric acid is avoided1 and the presence of an abundant quantity of potash prevents the formation of basic iron phosphate which is insoluble in nitric acid4 7#b7 ,citrate-,soluble ,phosphoric ,acid4--,one gram of the basic slag or phosphate is placed in a #ajj cubic centimeter flask and covered with ,wagner's acid citrate solution making the total volume up to #ajj cubic centimeters4 ,with frequent shaking the flask is kept at #dj for an hour1 or it may be allowed to stand for twelve hours at room temperature with frequent shaking4 ,in fifty cubic centimeters of the filtrate from this flask the phosphoric acid is determined by the magnesia mixture as described4 ,since1 in the present case1 the precipitate of ammonium magnesium phosphate contains some silicic acid it cannot be directly ignited but must be treated in the following manner3 ,the precipitate and the filter are thrown into a porcelain dish1 the filter-paper torn up into shreds with a glass rod1 the precipitate dissolved in nitric acid1 neutralized with ammonia1 acidified with acetic1 and treated with uranium solution4 ,the phosphoric acid may also be estimated by the gravimetric method by dissolving the precipitate again in hydrochloric or nitric acid1 evaporating to dryness1 and drying for one hour at from #aaj to #abj1 dissolving again in hydrochloric acid1 filtering1 and washing the precipitate well4 ,the filtrate1 which is now free from silica1 can be treated with ,joulie's solution1 precipitated with magnesia mixture1 the precipitate washed1 ignited1 and weighed as described4 ,the molybdenum method is preferred in the estimation of citrate-soluble phosphoric acid1 especially in slags4 ,for this purpose fifty cubic centimeters of the filtrate from the solution of one gram of slag in #ajj cubic centimeters of ,wagner's citrate liquid are treated with #ajj cubic centimeters of molybdenum solution and thirty cubic centimeters of ammonium nitrate solution1 warmed for twenty minutes at #hj1 filtered after cooling1 and the yellow precipitate washed with cold water4 ,the water will gradually dissolve all the silicic acid from the yellow precipitate and carry it into the filtrate4 ,the yellow precipitate is then dissolved in two and one-half per cent liquid ammonia and precipitated with magnesia mixture and the precipitate washed1 ignited1 and weighed in the way described4 #aah4 ,determination of ,phosphoric ,acid in ,superphosphates4--7#a7 ,citrate-,soluble ,phosphoric ,acid4--,five grams of the superphosphate are rubbed with #ajj cubic centimeters of ,wagner's acid citrate solution in a mortar and washed into a flask of #ejj cubic centimeters content and diluted to #ejj cubic centimeters with water4 ,with frequent shaking the flask is allowed to stand for twelve hours1 after which its contents are filtered4 ,fifty cubic centimeters of the filtrate are treated with ten cubic centimeters of the ,joulie solution and fifteen cubic centimeters of the magnesia mixture and1 if necessary1 made distinctly alkaline with ammonia1 vigorously stirred1 and1 after two hours1 filtered4 ,the precipitate is washed1 ignited1 and weighed as described1 or titrated1 after solution in nitric acid and the addition of sodium acetate1 with uranium solution4 ,example3 ,the weighed precipitate has #j4abgb gram ,mg,p,o then the phosphate contains #ab4gb #b #j4fd #af4bh per cent of citrate-soluble ,p,o4 7#b7 ,water-,soluble ,phosphoric ,acid4--,twenty grams of superphosphate are rubbed in a mortar and washed into a flask of one liter content and made up to the mark with water4 ,after two hours' digestion with frequent shaking1 the contents of the flask are filtered through a folded filter4 ,twenty-five cubic centimeters of the filtrate equivalent to five-tenths gram of the substance are precipitated with magnesia mixture1 the precipitate filtered1 washed1 ignited1 and weighed1 or the moist filtrate may be dissolved upon the filter with a little nitric acid1 treated with sodium acetate1 and titrated1 as described1 with uranium solution4 ,example3 #ad4e cubic centimeters of the uranium solution are required for the precipitate from twenty-five cubic centimeters of the original solution #j4e gram superphosphate2 it contains then #ad4e #j4jjdde #j4jfde gram ,p,o4 ,consequently the superphosphate contains #ab4ij per cent of water-soluble ,p,o4 ,total ,phosphoric ,add4--,twenty grams of the superphosphate are boiled with fifty cubic centimeters of hydrochloric acid of from #af to #ah ,beaum for about ten minutes and1 after cooling1 made up to one liter with water and filtered4 ,twenty-five cubic centimeters of the filtrate are treated with ten cubic centimeters of ,joulie's citrate solution1 a few pieces of filter-paper thrown in1 fifteen cubic centimeters of magnesia mixture added1 and the whole thoroughly stirred4 ,after standing two hours the contents of the flask are filtered and the precipitate is washed with dilute ammonia and the filter and the precipitate are placed in a platinum crucible4 ,the crucible is heated slowly until the moisture is driven off and the filter burned4 ,then the temperature is gradually raised to a white heat4 ,the residue is cooled and weighed4 ,example3 ,the precipitate weighs1 after the subtraction of the filter ash1 #j4acij gram2 then the superphosphate contains #ac4ij #b #j4fd #ag4gi per cent phosphoric acid4 ,,miscellaneous ,,notes ,,on ,,phosphates ,,and ,,phosphatic ,,fertilizers4 #aai4 ,time ,required for ,precipitation of ,phosphoric ,acid4--,the length of time required for the complete precipitation of the phosphoric acid by molybdate mixture is perhaps much less than generally supposed4 ,at #fe the precipitation1 as shown by de ,roode1 is complete in five minutes4#ajj ,in a given case the weight of pyrophosphate obtained after five minutes was #j4jfgf gram1 and exactly the same weight was found after twenty-four hours4 ,in view of these facts analysts would often be able to save time by omitting the delay usually demanded by the setting aside of the yellow precipitate for a few hours in order to secure a complete separation of the phosphoric acid4 ,in the method of the official chemists it is directed that the digestion at #fe be continued for one hour1 and this time may possibly be shortened with advantage4 ,in all cases1 however1 where there is any doubt in regard to the complete separation1 some of the molybdate solution should be added to the filtrate and1 with renewed digestion1 it should be noted whether any additional precipitate be formed4 #abj4 ,examination of the ,pyrophosphate4--,in fertilizer control it is not usually thought necessary to examine the magnesium pyrophosphate for impurities4 ,among those most likely to be found is silica4 ,it is proper1 in all cases where accuracy is required1 to dissolve the precipitate in nitric acid1 boil for some time to convert the pyro- into orthophosphate1 and reprecipitate with molybdate and magnesia mixture4 ,this treatment will separate the silica which remains practically insoluble after the first ignition4 ,it has been observed by some analysts that the results obtained by the official method are a trifle too high and also that on re-solution the second precipitate of pyrophosphate weighs less than the first4#aja ,the difference in most cases is very little but it may become a quantity of considerable magnitude in samples where soluble silica is found in notable quantities4 ,the danger of contamination with iron1 alumina1 and arsenic has already been mentioned but it is not of sufficient importance to warrant further attention4 #aba4 ,iodin in ,phosphates4--,the presence of iodin has been detected in many natural phosphates and is of interest in the discussion of the problem of their origin4#ajb ,a qualitative test for the detection of iodin may be applied in the following manner3 ,some finely ground phosphate is mixed with strong sulfuric acid and the gases arising from the reaction are aspired into some carbon disulfid or chloroform4 ,the violet coloration arising indicates the presence of iodin4 ,the gases carrying the iodin may also be brought into contact with starch-paste producing the well-known blue color4 ,the quantity of iodin present in a phosphate is rarely more than one or two-tenths of one per cent4 ,it can be determined as a silver salt1 in the absence of chlorin or by any of the standard methods found in works on qualitative analysis4 ,iodin is quite a constant constituent of ,florida phosphates4 ,for a quantitative determination1 the sample is treated with an excess of strong sulfuric acid in a closed flask and during the decomposition a stream of air is aspired through the flask and caused to bubble through absorption bulbs containing sodium hydroxid in solution4 ,the temperature of the decomposition may be raised to about #bjj4 ,after the solution of the sample the sodium iodid formed is oxidized by heating with potassium permanganate1 acidulated and mixed with a solution of potassium iodid to hold the free iodin in solution4 ,the free iodin is determined in the usual way by titration with standard sodium thiosulfate solution4 ,the reactions preparatory to the titration are represented by the following formulas3 #b,,ki ,h,,so ,k,,so #b;,,hi4 #b;,,hi ,h,,so #b;,h,o ,,so #b;,i4 #f;,i #f,na,o,h ,na,i,o #e,na,i #c;,h,o4 ,na,i #b,k,mn,o ,h,o ,na,i,o #b,,koh #b,mn,o4 ,,hio #e;,,hi #f;,i #c;,h,o4 ,the titration is represented by the following reaction3 #b,na,s,o #b;,i #b,na,i #b,na,i ,na,s,o4 ,the decinormal solution of sodium thiosulfate may be used4 ,grind the crystals of the salt to a fine powder1 dry between blotting papers1 and use #bd4h grams of the dried salt per liter4 ,the quantity of iodin found in phosphates is so minute that it is hardly worth while to make a quantitative determination of it4 #abb4 ,occurrence of ,chromium in ,phosphates4--,in some phosphates a small quantity of chromium has been found4 ,in a sample of phosphate from the ,island of ,los ,roques in the ,caribbean ,sea1 ,gilbert found three-fourths per cent of chromium oxid 7,cr,o74 ,the phosphates containing chromium have a greenish color and are characterized by great insolubility in solutions containing organic acids4 ,the chromium is to be determined by the usual methods described in mineral analysis4 #abc4 ,estimation of ,vanadium4--,in the complete analysis of basic slags it becomes necessary to determine the presence of vanadium and its quantity4 ,the method used in this laboratory for the purpose is the volumetric process of ,lindemann4#ajc ,it is conducted as follows3 ,dissolve four grams of the finely powdered slag in sixty cubic centimeters of dilute sulfuric acid 7#a3 #d71 boil for a few minutes1 cool1 make the volume up to #ajj cubic centimeters1 filter1 and take an aliquot part for the determination4 ,add decinormal potassium permanganate solution in slight excess to secure the oxidation of the vanadium to vanadium pentoxid4 ,add1 drop by drop1 a weak solution of ferrous sulfate until the pink color just disappears4 ,prepare a ferrous sulfate solution by dissolving #b4ahc grams of piano wire in sulfuric acid and making the volume to one liter4 ,titrate the vanadic mixture with this solution until a drop of the clear liquor removed and brought in contact with potassium ferricyanid shows a distinctive blue-green color4 ,one cubic centimeter of the ferrous sulfate solution is equivalent to #j4jjb gram of vanadium1 #j4jjbhhh gram of vanadium dioxid1 and #j4jjcfdh gram of vanadium pentoxid4 ,the ferrous sulfate solution may also be made and standardized by any of the approved methods in common use4 ,the method described by ,blair1 designed especially for the estimation of vanadium in iron and steel1 is conducted in the following manner3#ajd ,five grams of the drillings are dissolved in fifty cubic centimeters of nitric acid of #a4bd specific gravity4 ,the solution is evaporated to dryness in a porcelain dish and heated thereafter until the nitrates are nearly decomposed4 ,after cooling1 the dried mass is transferred to a mortar and finely ground with thirty grams of dry sodium carbonate and three grams of sodium nitrate4 ,the finely ground materials are placed in a platinum dish and fused for an hour at a high temperature4 ,spread the fused mass over the sides of the dish while cooling1 and afterwards dissolve in hot water1 filter1 and wash until the volume is a little over half a liter4 ,add nitric acid to decompose carbonates1 but not completely1 and boil to get rid of carbon dioxid1 being careful to keep the mass always slightly alkaline4 ,add nitric acid1 drop by drop1 until slightly in excess1 and then sodium carbonate to marked alkalinity1 boil1 and filter4 ,add a slight excess of nitric acid to the filtrate1 and the development of a yellow color will indicate the presence of vanadic acid4 ,add to the solution a small quantity of mercurous nitrate and then an excess of mercuric oxid1 suspended in water to render the solution neutral and insure the complete precipitation of mercurous vanadate4 ,the mercurous salt also precipitates phosphoric1 chromic1 tungstic1 and molybdic acids which may be present4 ,boil1 filter1 and wash the precipitate with hot water1 dry1 and ignite4 ,fuse the residue with sodium carbonate and a little nitrate4 ,dissolve the fused mass1 after cooling1 in a little water and filter4 ,add to the filtrate1 ammonium chlorid in excess1 from three to five grams for each #ajj cubic centimeters of the solution1 and allow to stand1 with occasional stirring1 for some time4 ,ammonium vanadate1 insoluble in a saturated solution of ammonium chlorid1 separates as a white powder4 ,it is necessary to keep the solution alkaline1 and a drop of ammonia should be added from time to time for this purpose4 ,the appearance of a yellowish tint at any time indicates that the solution has become acid1 and this acidity must be corrected1 or else the results will be too low4 ,separate the ammonium vanadate by filtration2 wash first with a saturated solution of ammonium chlorid containing a little free ammonia1 and then with alcohol4 ,dry1 ignite1 and moisten with a few drops of nitric acid2 again ignite to obtain the compound as vanadium pentoxid4 ,this compound contains #ef4bb per cent of vanadium4 ,the method of ,rosenheim and ,holversheet may also be used4#aje ,it is based on the preliminary precipitation of the vanadic acid as a barium or lead salt4 ,the substance supposed to contain vanadium is first brought into solution in such a manner as to secure it as vanadic acid1 which is then precipitated with barium chlorid or lead acetate4 ,the precipitate is boiled with hydrochloric acid and potassium bromid1 and the liberated bromin determined by the quantity of iodin set free from potassium iodid4 ,in the absence of bodies1 such as molybdic acid1 which are reduced by sulfurous acid or hydrogen sulfid1 the vanadic acid may also be determined by reducing it with one of these reagents and1 after removing the excess by boiling1 titrating the vanadium tetroxid with potassium permanganate4 ,when vanadic and phosphoric acids occur together the former may be first reduced to tetroxid with sulfurous acid1 and after expelling excess of this reagent1 the phosphoric acid may be separated with molybdate solution and removed by filtration4 ,when the amount of vanadic acid is large the phosphoric acid should be separated rapidly at #ee-fj1 using a considerable excess of the molybdate2 or the vanadic acid may first be determined in the solution volumetrically by the bromin process above described1 and afterwards the phosphoric acid obtained by evaporating to dryness with a little sulfuric acid1 taking the residue up with water1 reducing the vanadic with sulfurous acid and precipitating the phosphoric acid with molybdate solution as described above4 #abd4 ,fluorin in ,bones4--,fluorin is not only a constituent of mineral phosphates but also of bones4 ,according to the researches of ,carnot there is often as much as one-half per cent of calcium fluorid in bones and teeth4#ajf ,gabriel has suggested a means of determining a minimum limit of fluorin in bones and teeth by the development of etchings in comparison with known quantities of pure calcium fluorid4 ,the minimum quantity of calcium fluorid necessary to produce a distinct etching1 in known conditions1 having been determined1 the test is applied to known weights of ignited bone or teeth4 ,he concludes from his results1 that the ash of bones and teeth often contains less than one-tenth per cent of fluorin4 ,since1 however1 there is a loss of fluorin from calcium fluorid1 on ignition1 the whole of the fluorin may not have been available in the tests described4 #abe4 ,note on the ,separation of ,iron and ,aluminum ,phosphates from the ,calcium ,compound4--,there are many points of difference noted in the descriptions given by authors of the deportment of the iron1 and aluminum phosphates in presence of a large excess of the calcium salt4 ,especially is this true of the statements made by ,hess and ,glaser#ajg in paragraphs #cd and #ce4 ,the subject is of such importance1 from an analytical point of view1 as to merit a careful study4 ,in this laboratory a thorough investigation of the mutual deportment of these three phosphates has been made by ,brown with the following results3#ajh ,when a mixture containing a known weight of the salts was treated exactly as ,hess directs1 in no case was there a complete separation of the iron aluminum phosphate from the calcium salt4 ,in order to discover the cause of the failure1 pure solutions of calcium and iron aluminum phosphates were treated under identical conditions by the necessary reagents4 ,fifty cubic centimeters of a solution of calcium phosphate1 containing about one gram of the salt1 were treated with #ajj cubic centimeters of water and fifty cubic centimeters of the commercial ammonium acetate containing #aej grams of the salt in a liter4 ,an immediate precipitate was produced at ordinary temperature1 and on heating to #fj it became abundant4 ,the addition of ammonium chlorid1 phosphate1 and nitrate in successive portions1 does not prevent the precipitation4 ,making the solution more dilute lessens the difficulty when twenty cubic centimeters of a ten per cent solution of ammonium phosphate are first added1 followed by the usual quantity of ammonium acetate2 a clear crystalline precipitate is sometimes observed4 ,experience also shows that the trouble is not due to an excess of the ammonium acetate4 ,in treating a solution of iron aluminum phosphate1 in similar circumstances1 with the ammonium acetate1 it is found that a complete precipitation takes place4 ,since diluting the solution of the calcium salt diminishes its tendency to form a precipitate with the ammonium acetate the true method of separation seems to lie in that direction4 ,the calcium salt is held completely in solution when the separation is made in the following way4 ,the solution containing the mixed phosphates is diluted so as to contain not more than one gram thereof in half a liter4 ,to this is added one drop of dimethylanilin orange1 and afterwards ammonium hydroxid1 until a very slight precipitate is formed4 ,the mixture is heated to #gj and from twenty to twenty-five cubic centimeters of a twenty-five per cent solution of acid ammonium acetate are added1 enough to change the rose color of the indicator to orange4 ,the iron aluminum phosphate is separated by filtration and washed with a hot five per cent solution of ammonium nitrate4 ,the washed precipitate shows no impurity due to calcium1 as proved by dissolving it1 reprecipitating and filtering1 adding ammonium hydroxid to the filtrate1 and heating for a long time4 ,sometimes a slight troubling of the clear liquid may be observed which may be due to a slight solubility of the iron aluminum phosphate in washing1 an accident that may occur if the temperature be allowed to fall below #gj1 but no weighable amount of material is obtained4 ,if due to calcium phosphate1 a greater dilution in the first precipitation will remove even this mere trace of that salt4 ,in the above conditions the contamination of the iron aluminum precipitate with calcium phosphate may be entirely avoided4 ,we had also undertaken here the problem of separating the phosphoric acid by the citrate method1 followed by a destruction of the citric acid in the filtrate by combustion with sulfuric acid according to the kjeldahl process1 and final separation of the iron and alumina in the residues when our attention was called to substantially the same process as described by ,jean4#aji ,the method merits a further critical examination4 #abf4 ,phosphoric ,acid ,soluble in ,ammonium ,citrate4--,there is no other point connected with the determination of phosphoric acid which has excited so much discussion and about which there is such difference of opinion as the solubility of phosphates in ammonium citrate4 ,it was clearly established by ,huston1 in #ahhb1 that the ammonium citrate1 as used in fertilizer analysis1 would attack normal tricalcium phosphate as it exists in bones4#aaj ,in a raw bone1 finely ground1 containing #bj4bh per cent of phosphoric acid1 the following quantities were found to be soluble in a neutral ammonium citrate solution of #a4ji specific gravity4 ,time of digestion1 thirty minutes4 ,temperature #cj #dj #ej #fj ,per cent ,p,o dissolved #b4gf #d4ja #c4ci #e4hh ,from this it appears that the quantity of acid dissolved increases with the temperature of digestion with the exception of the number obtained at #ej4 ,when the time of digestion was increased there was also found a progressive increase in the amount of acid passing into solution4 ,at #dj for forty-five minutes the per cent dissolved was #d4ig1 and at #dj for one hour it was #e4ib4 ,these early determinations had the effect of calling attention to the thoroughly empirical process which was in use1 in many modified forms1 by agricultural chemists1 the world over for determining so-called reverted phosphoric acid in fertilizers4 ,since the publication of the paper above named many investigations have been undertaken by ,huston and others relating to this matter4#aaa ,the general results of these studies1 tabulated by ,huston1 are given below4#aab ,,influence ,,of ,,the ,,time ,,of ,,digestion4 7,a7 ,temperature1 degrees ,c4 7,b7 ,citrate-soluble phosphoric acid4 7,c7 ,total phosphoric acid4 ,material4 ,authority4 7,a7 ,time of 7,b7 7,c7 digestion4 ,per cent4 ,per cent4 ,bone meal1 ,f4 ,b4 ,dancy1 #fe hour #aj4fj #ai4ge #fe #a 8 #aa4bh #ai4ge ,orchilla ,f4 ,b4 ,dancy1 #fe 8 #f4fb #ba4fh guano1 #fe #a 8 #f4he ,navassa ,f4 ,b4 ,dancy1 #fe 8 #d4fd #ca4bg rock1 #fe #a 8 #d4ha #ca4bg ,navassa ,f4 ,b4 ,dancy1 #fe 8 #i4jj #aa4dg superphos41 #fe #a 8 #i4ba #aa4dg ,bone meal1 ,h4 ,a4 ,huston1 #dj 8 #d4ja #bj4bh #dj #a 8 #e4ib #bj4bh ,bone meal1 ,h4 ,a4 ,huston and #fe 8 #f4ag #bc4eh raw1 ,w4 ,j4 ,jones1 ,jr41 #fe #a 8 #f4di #bc4eh #fe #b hours #h4bb #bc4eh #fe #e 8 #i4ca #bc4eh ,steamed ,h4 ,a4 ,huston and #fe hour #aj4ei #bg4fg bone1 ,w4 ,j4 ,jones1 ,jr41 #fe #a 8 #ab4ba #fe #b hours #ad4fa #fe #e 8 #ag4id #fe #aj 8 #ai4gc ,florida ,h4 ,a4 ,huston and #fe hour #j4ef #ai4ge soft rock1 ,w4 ,j4 ,jones1 ,jr41 #fe #b hours #a4fi #fe #e 8 #a4dg ,precipitated ,h4 ,a4 ,huston and #fe hour #bf4gb #cc4cd calcium ,w4 ,j4 ,jones1 ,jr41 #fe 8 #bg4bf phosphate #fe #a 8 #bg4bh from glue #fe #b hours #bg4bi works1 ,pamunky ,h4 ,a4 ,huston and #fe hour #d4dc #ac4hd phosphate1#aac ,w4 ,j4 ,jones1 ,jr41 #fe #a 8 #h4bh #fe #b hours #aj4cd #fe #e 8 #aa4hj #fe #aj 8 #ab4eh ,calcined ,h4 ,a4 ,huston and #fe hour #ba4bd #de4ae ,redonda1 ,w4 ,j4 ,jones1 ,jr41 #a 8 #ca4gj #b hours #cf4ib #e 8 #da4jj #aj 8 #db4gj ,south ,h4 ,a4 ,huston and #fe hour #b4hb #be4ea ,carolina ,w4 ,j4 ,jones1 ,jr41 #a 8 #c4ac rock1 #b hours #c4eg #e 8 #c4hh ,,influence ,,of ,,temperature4 7,a7 ,temperature1 degrees ,c4 7,b7 ,citrate-soluble phosphoric acid4 7,c7 ,total phosphoric acid4 ,material4 ,authority4 ,time of 7,a7 7,b7 7,c7 ,digestion ,per cent4 ,per cent4 ,apatite ,t4 ,s4 ,gladding#aad hour #dj #j4cj ,canadian1 8 #fe #j4ef ,orchilla ,t4 ,s4 ,gladding1 8 #dj #d4fc guano1 8 #fe #d4ha ,south ,t4 ,s4 ,gladding1 8 #dj #a4ji ,carolina 8 #fe #a4ce river rock1 ,navassa ,t4 ,s4 ,gladding1 8 #dj #b4gc rock1 8 #fe #b4ec ,grand ,t4 ,s4 ,gladding1 8 #dj #a4af ,connetable1 8 #fe #a4if ,redonda1 ,s4 ,w4 ,johnson and 8 #dj #a4gj #cf4fh ,e4 ,h4 ,farrington1 8 #fe #a4he ,south ,s4 ,w4 ,johnson and 8 #dj #a4cb #be4dh ,carolina ,e4 ,h4 ,farrington1 8 #fe #a4fe rock1 ,orchilla ,s4 ,w4 ,johnson and 8 #dj #d4ib #ba4je guano1 ,e4 ,h4 ,farrington1 8 #fe #e4he ,navassa ,s4 ,w4 ,johnson and 8 #dj #d4aj #bi4ij rock1 ,e4 ,h4 ,farrington1 8 #fe #d4bb ,acid ,s4 ,w4 ,johnson and 8 #dj #aa4ie #af4ej ,navassa1 ,e4 ,h4 ,farrington1 8 #fe #ac4ec ,fine-ground ,s4 ,w4 ,johnson and 8 #dj #i4dj #bc4ej bone1 ,e4 ,h4 ,farrington1 8 #fe #ab4ij ,south ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #a4gb #bd4ej ,carolina also ,h4 ,c4 ,white1 8 #fe #b4aa land rock1 ,orchilla ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #f4dh #ae4he guano1 also ,h4 ,c4 ,white1 8 #fe #f4ge ,calcined ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #e4gj #dd4he ,redonda1 also ,h4 ,c4 ,white1 8 #fe #aj4bj ,raw ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #d4di #dc4gi ,redonda1 also ,h4 ,c4 ,white1 8 #fe #g4ib ,acid ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #c4ee #ah4be phosphate1 also ,h4 ,c4 ,white1 8 #fe #d4je ,s4 ,c4 #aj4ce per cent water-soluble1 ,acid ,c4 ,v4 ,sheppard1 ,jr4 8 #dj #aj4he #af4bj ,navassa1 also ,h4 ,c4 ,white1 8 #fe #aa4jj #b4he per cent water-soluble1 ,bone1 ,h4 ,a4 ,huston1 8 #cj #b4gf #bj4bh 8 #dj #d4ja 8 #ej #c4ci 8 #fj #e4hh ,acid ,sheppard and 8 #dj #c4df #ae4ie phosphate1 ,robertson1 8 #fj #c4hb #aa4da per cent water-soluble1 ,calcined ,h4 ,a4 ,huston1 8 #dj #b4ah #de4df ,redonda1 8 #ej #e4eb 8 #fe #ba4bd 8 #ge #cb4ij 8 #he #ci4eb ,calcined ,h4 ,a4 ,huston and #e hours #dj #bf4gh #db4ij ,redonda1 ,w4 ,j4 ,jones1 ,jr41 #e 8 #fe #ch4ai #e 8 #he #da4eg ,pamunky ,h4 ,a4 ,huston and #e 8 #dj #c4aj #ac4hd phosphate1 ,w4 ,j4 ,jones1 ,jr41 #e 8 #fe #aa4hj #e 8 #he #ab4hb ,raw bone1 ,h4 ,a4 ,huston and #b 8 #dj #e4if #bc4eh ,w4 ,j4 ,jones1 ,jr41 #b 8 #fe #h4bb #b 8 #he #h4ga ,steamed ,h4 ,a4 ,huston and #e 8 #dj #af4jb #bg4fg bone1 ,w4 ,j4 ,jones1 ,jr41 #e 8 #fe #bj4bb #e 8 #he #bj4ff ,precipitated ,h4 ,a4 ,huston and #b 8 #dj #bd4ad #cc4cd calcium ,w4 ,j4 ,jones1 ,jr41 #b 8 #fe #bc4de phosphate #b 8 #he #bb4df from glue works1 ,florida ,h4 ,a4 ,huston and #b 8 #dj #j4jj #ai4ge soft rock1 ,w4 ,j4 ,jones1 ,jr41 #b 8 #fe #a4fi #b 8 #he #a4ii ,,influence ,,of ,,quantity ,,of ,,material ,,used4 7,a7 ,temperature1 degrees ,c4 7,b7 ,quantity of material used4 7c7 ,citrate-soluble phosphoric acid4 7,d7 ,total phosphoric acid4 ,material4 ,authority4 ,time 7,a7 7,b7 7,c7 7,d7 ,grams4 ,per cent4 ,per cent4 ,orchilla ,f4 ,b4 ,dancy1 hour #dj #b4j #i4id #ba4fh guano1 8 #dj #a4j #ab4ad 8 #dj #j4e #ac4ea 8 #fe #b4j #f4fb 8 #fe #a4j #i4cc ,redonda1 ,s4 ,w4 ,johnson 8 #dj #b4j #a4gj #cf4fh and ,e4 ,h4 8 #dj #j4d #c4df ,farrington1 8 #fe #b4j #a4he 8 #fe #j4d #e4bf ,south ,s4 ,w4 ,johnson 8 #dj #b4j #a4cb #be4dh ,carolina and ,e4 ,h4 8 #dj #j4d #a4cc rock1 ,farrington1 8 #fe #b4j #a4fe 8 #fe #j4d #c4cf ,orchilla ,t4 ,s4 ,gladding1 8 #fe #b4j #e4hg guano1 8 #fe #j4d #ac4je ,calcined ,h4 ,a4 ,huston1 8 #fe #j4e #af4hj #de4df ,redonda1 8 #fe #a4j #ah4bf 8 #fe #b4j #ba4bd 8 #fe #c4j #bc4bb 8 #fe #e4j #bd4ff 8 #fe #aj4j #bh4fd ,calcined ,h4 ,a4 ,huston1 #e hours #fe #j4e #da4gg #de4df ,redonda1 #e 8 #fe #b4j #da4ec #e 8 #fe #h4j #ci4hf ,pamunky ,h4 ,a4 ,huston #e 8 #fe #j4e #aa4ha #ac4hd phosphate1 and ,w4 ,j4 #e 8 #fe #b4j #aa4hj ,jones1 ,jr41 #e 8 #fe #d4j #aa4dd ,raw bone1 ,h4 ,a4 ,huston #b 8 #fe #j4e #af4di #bc4eh and ,w4 ,j4 #b 8 #fe #b4j #h4bb ,jones1 ,jr41 #b 8 #fe #d4j #g4bb ,steamed ,h4 ,a4 ,huston #e 8 #fe #j4e #bf4dj #bg4fg bone1 and ,w4 ,j4 #e 8 #fe #b4j #ag4id ,jones1 ,jr41 #e 8 #fe #d4j #ab4ab ,precipitated ,h4 ,a4 ,huston #b 8 #fe #j4e #cc4cd #cc4cd calcium and ,w4 ,j4 #b 8 #fe #b4j #bg4bi phosphate ,jones1 ,jr41 #b 8 #fe #d4j #ai4di from glue works1 ,florida ,h4 ,a4 ,huston #b 8 #fe #j4e #e4ej #ai4ge soft rock1 and ,w4 ,j4 #b 8 #fe #b4j #a4fi ,jones1 ,jr41 #b 8 #fe #d4j #a4bg ,influence of ,acidity and ,alkalinity4 7,a7 ,temperature1 degrees ,c4 7,b7 #ajj cc neutral citrate citric acid4 7,c7 #ajj cc neutral citrate ammonia equivalent to citric acid4 7,d7 ,per cent of phosphoric acid dissolved4 7,e7 ,per cent total phosphoric acid4 ,material4 ,authority4 ,time 7,a7 7,b7 7,c7 7,d7 7,e7 ,navassa ,t4 ,s4 ,gladding#aae hour #fe #j4jj #j4jj #b4ec rock1 8 #fe #j4gcc gm #d4hg 8 #fe #j4gcc gm #a4bb ,south ,t4 ,s4 ,gladding1 8 #fe #j4jj #j4jj #a4ce ,carolina 8 #fe #j4gcc 8 #b4hi rock1 8 #fe #j4gcc 8 #a4jf ,grand ,t4 ,s4 ,gladding1 8 #fe #j4jj #j4jj #a4ig connetable1 8 #fe #j4gcc 8 #a4ab 8 #fe #j4gcc 8 #aa4dd ,dissolved ,h4 ,b4 ,mc,donnell1 8 #fe #j4jj #j4jj #b4di #aa4ea bone-black 8 #fe #j4ja 8 #b4db and 8 #fe #j4ja 8 #b4cg cottonseed-meal1 ,ground ,h4 ,b4 ,mc,donnell1 8 #fe #j4jj #j4jj #h4ff #bf4fb bone1 8 #fe #j4ja 8 #i4ah 8 #fe #j4ja 8 #h4jj ,calcined ,h4 ,b4 ,mc,donnell1 8 #fe #j4jj #j4jj #cj4fa #de4aa ,redonda1 8 #fe #j4ja 8 #bi4db 8 #fe #j4ja 8 #cb4dg ,dissolved ,h4 ,a4 ,huston1 8 #fe #j4jj #j4jj #b4bd #aa4cb bone-black 8 #fe #a4jj 8 #b4bd and 8 #fe #a4jj 8 #b4ba cottonseed-meal1 ,ground ,h4 ,a4 ,huston 8 #fe #j4jj #j4jj #h4gh #bf4ce bone1 and ,w4 ,j4 8 #fe #a4jj 8 #ac4dh ,jones1 ,jr41 8 #fe #a4jj 8 #e4ce ,calcined ,h4 ,a4 ,huston 8 #fe #j4jj #j4jj4 #be4ed #de4ae ,redonda1 and ,w4 ,j4 8 #fe #a4jj 8 #ah4hd ,jones1 ,jr41 8 #fe #a4jj 8 #ce4bj ,south ,h4 ,a4 ,huston 8 #fe #j4jj #j4jj #a4ha #bg4fg ,carolina and ,w4 ,j4 8 #fe #a4jj 8 #d4ei rock1 ,jones1 ,jr41 8 #fe #a4jj 8 #j4gd ,basic ,h4 ,a4 ,huston 8 #fe #j4jj #j4jj #f4ih #ai4db slag1 and ,w4 ,j4 8 #fe #a4j 8 #aj4ab ,jones1 ,jr41 8 #fe #a4j 8 #e4di ,pamunky ,h4 ,a4 ,huston #e h'rs #fe #j4jj #j4jj #aa4hj #ac4hd phosphate1 and ,w4 ,j4 #e 8 #fe #a4j #aa4gi ,jones1 ,jr41 #e 8 #fe #a4j 8 #ab4bh ,raw bone1 ,h4 ,a4 ,huston #b 8 #fe #j4jj #j4jj #h4bb #bc4eh and ,w4 ,j4 #b 8 #fe #a4j 8 #aa4bj ,jones1 ,jr41 #b 8 #fe #a4j 8 #d4jb ,steamed ,h4 ,a4 ,huston #e 8 #fe #j4jj #j4jj #ag4id #bg4fg bone1 and ,w4 ,j4 #e 8 #fe #a4j 8 #bb4ee ,jones1 ,jr41 #e 8 #fe #a4j 8 #i4fd ,precipitated ,h4 ,a4 ,huston #b 8 #fe #j4jj #j4jj #bd4bj #cc4cd calcium and ,w4 ,j4 #b 8 #fe #a4j 8 #cj4gj phosphate ,jones1 ,jr41 #b 8 #fe #a4j 8 #bj4fg from glue works1 ,florida ,h4 ,a4 ,huston1 #b 8 #fe #j4jj #j4jj #a4fi #ai4ge soft rock1 and ,w4 ,j4 #b 8 #fe #a4j 8 #c4cg ,jones1 ,jr41 #b 8 #fe #a4j 8 #j4gb ,calcined ,h4 ,a4 ,huston #e 8 #fe #j4jj #j4jj #dj4fd #dd4cj ,redonda1 and ,w4 ,j4 #e 8 #fe #a4j 8 #dj4je ,jones1 ,jr41 #e 8 #fe #a4j 8 #da4ja ,in the above tabulations no mention is made of the work of ,fresenius1 ,neubauer1 and ,luck1 on whose researches the citrate method is based1 but an examination of their original paper shows that the temperature conditions are not carefully enough controlled to justify us in tabulating their results4#aaf ,an attempt has been made to include in the above tables1 work made under well-defined conditions1 which will illustrate the various points under consideration4 ,while each authority of value upon the subject is represented1 no attempt has been made to include all the work done by any of them4 ,one element that seems to have been generally overlooked in discussing the problem is that nearly all results have been obtained from one-half hour's treatment of the material4 ,this means simply the study of an incomplete reaction1 and one which is interrupted while the solution is very rapidly going on4 ,this1 of course1 is only clearly brought out by a comparison of long-time and short-time work in the various tables4 ,in the opinion of ,huston very much more work will have to be done before it can be assumed that we have any very clear knowledge of this subject1 and very likely the final result will be that all kinds of goods cannot be examined by the same method4 ,the fact that half a gram of dicalcium phosphate is instantly soluble in #ajj cubic centimeters of citrate solution1 at ordinary temperatures1 while an equal amount of iron and aluminum phosphate is acted upon very slowly at ordinary temperatures will probably have to be taken into consideration1 as well as the fact that dicalcium phosphate is less soluble in hot solutions of ammonium citrate than it is in cold solutions1 while the reverse is true of the precipitated iron and aluminum phosphate4 ,at present1 the only conclusion that can be safely drawn from the work1 is that it would be unsafe to make any generalization upon the subject until more facts are at hand1 except that the present methods are unscientific and1 unsatisfactory4 ,as the work progresses1 new features present themselves1 and in such a way as to show that they must be given careful consideration before drawing any final conclusions in the matter4 #abg4 ,arbitrary ,determination of ,reverted ,phosphoric ,acid4--,the so-called reverted phosphoric acid1 that is1 the acid insoluble in water and soluble in a solution of ammonium citrate1 is the most difficult constituent of commercial fertilizers from the point of view of the scientific analyst4 ,a review of all the standard methods which have been given in the preceding pages for its determination must convince every careful observer that1 as a rule1 each process is based on arbitrary standards1 and can give only concordant results when carried out under strictly unvarying conditions4 ,for this reason there can be no just comparison between the results obtained by different methods1 which vary from each other only in slight particulars4 ,when1 on the other hand1 the processes are radically different1 the deviations in data become more pronounced4 ,in such a condition of affairs the analyst is left to choose between methods4 ,he must be guided in his choice not only by what seems to be the most scientific and accurate process1 but also1 to a certain extent1 by the general practice of his professional brethren4 ,for this country1 therefore1 it is strongly urged that the methods adopted by the ,association of ,official ,agricultural ,chemists1 be followed in every detail4 ,by the phrase 8reverted phosphoric acid10 was originally meant an acid once soluble in water1 as ,ca,h7,,po71 and afterwards changed to a form insoluble in water1 but soluble in ammonium citrate as ,ca,h7,,po74 ,but in practice this has never been the true signification of the term4 ,in the manufacture of acid and superphosphates there is formed1 more or less of the dicalcium phosphate1 either directly or after a time1 and this salt which1 in no sense can be called reverted1 is entirely soluble in ammonium citrate4 ,the iron and aluminum phosphates are also1 to a certain degree1 soluble in the same reagent4 ,when an acid phosphate1 containing various forms of calcium phosphate1 is applied to a soil containing iron and alumina1 the soluble parts of the compound tend to become fixed by union with those bases1 or by precipitation as ,ca,h7,,po74 ,but it is not alone reverted phosphate formed in this way1 which the analyst is called on to determine in a fertilizer1 although he may have occasion to treat it in soil analysis4 ,the expression 8reverted phosphoric acid10 therefore1 in practice not only includes a dicalcium phosphate1 which once may have been the monocalcium salt1 but also all of that salt originally existing in the superphosphate1 and formed directly during its manufacture1 as well as any iron and aluminum phosphates present which are soluble in ammonium citrate4 ,the expression 8citrate-soluble0 is1 therefore1 to be preferred to 8reverted0 phosphoric acid4 ,in the reversion of the phosphoric acid in superphosphates the iron plays a far more important role than the aluminum sulfate4 ,it was formerly supposed that the reversion took place as indicated in the following formula3 #b;,ca,h7,,po7 ,fe,o #b7;,ca,h,p,o1 ,fe,p,o7 #c;,h,o1 while ,wagner affirms that the reverted acid compounds consist of varying quantities of ferric oxid1 aluminum oxid1 phosphorus pentoxid1 and calcium oxid1 in various states of combination4#aag ,the more probable reaction is the following3 #c;,ca,h7,,po7 ,fe7,,so7 #d;,h,o #b7;,fe,p,o1 #b;,h,,po1 #b;,h,o7 #c;,ca,s,o4 ,this reaction can be demonstrated by adding to a superphosphate solution one of a ferric salt4 ,in addition to free phosphoric acid1 iron phosphate is separated1 which gradually passes into an insoluble form by the abstraction of water due to the crystallization of the gypsum4 ,the alumina present in a superphosphate seems to have no direct influence on the process of reversion4 ,its phosphate salt is not acted on by the acid calcium phosphate4 ,even when a superphosphate solution is treated with alum no precipitation is produced1 except on warming1 and this disappears when the mass is again cold4 ,it is therefore not necessary in the process of manufacture to separate the alumina by digestion with a hot soda-lye before treating the mass with sulfuric acid4 ,in order to avoid the reversion of the phosphoric acid several plans have been proposed4 ,one of the best is to use a little excess of sulfuric acid in the manufacture4 ,this tends to hold the phosphoric acid in soluble form but is objectionable on account of drying1 handling1 and shipping the fertilizer4 ,during the digestion1 moreover1 it is important that the temperature does not rise above #abj4 ,another method consists in adding to the dissolved rock a quantity of common salt chemically equivalent to its iron content4 ,ammonium sulfate also helps to hold the phosphoric acid water-soluble4 #abh4 ,influence of ,movement4--,the influence of time and temperature of digestion1 and of variations in the composition of the ammonium citrate on the quantity of phosphoric acid dissolved by that reagent has been pointed out4 ,of great importance also in the process is the character of the movement to which the materials are subjected during the digestion4 ,for this reason various mechanical devices have been constructed to secure uniformity of solution4 ,inasmuch as the temperature factor must also be faithfully observed1 the best of these devices are so arranged as to admit of a uniform motion within a bath of water kept at the desired temperature which1 by the ,association method1 is #fe4 ,illustration3 ,,figure #h4 ,,huston',s ,,digesting ,,apparatus4 #abi4 ,digestion ,apparatus for ,reverted ,phosphates4--,the digestion apparatus used by ,huston consists of two wheels twenty-five centimeters in diameter1 mounted on the same axis1 having a clear space of four and one-half centimeters between them4#aah ,in the periphery of each wheel are cut twelve notches1 which are to receive the posts bearing the rings through which the necks of the flasks pass4 ,the posts are held in place by nuts which are screwed down on the faces of the wheel4 ,should it become necessary to take the apparatus apart1 it is only necessary to loosen the nuts and the set screw holding one wheel to the shaft and all the parts can at once be removed4 ,the posts extend ten centimeters beyond the face of the wheels1 and the rings are four centimeters in internal diameter4 ,perforated plates1 bearing a cross-bar1 and held in place by strong spiral springs attached to the plate and the base of the posts1 serve to hold the flasks in place4 ,each plate has a number stenciled through it for convenience in identifying the flasks when it is time to remove them4 ,attached to the outside of each post1 close to the outer end1 is a heavy wire which passes entirely around the apparatus1 serving to keep the plates in place after they are removed from the flasks4 ,the apparatus is mounted on a substantial framework1 thirty-six centimeters high and thirty centimeters wide at the base4 ,the space in which the wheel revolves is fourteen centimeters wide4 ,the base bars connecting the two sides are extended seven centimeters beyond one side1 and serve for the attachment of lateral bracing4 ,at the top of the framework1 at one side1 is attached a heavy bar forty-five centimeters long1 which serves to carry the cog gearing which transmits the power4 ,the upright shaft carries a cone pulley to provide for varying the speed4 ,the usual speed is two revolutions a minute for the wheel carrying the flasks4 ,the entire apparatus is made of brass4 ,the details of construction are shown in ,fig4 #h4 ,round-bottomed flasks are used1 and rubber stoppers are held in place by tying or by a special clamp shown at the lower right-hand of the figure4 ,when high temperatures are used1 the plates and flasks are handled by the hooks shown at the left and right-hand upper corners of the figure4 ,when any other than room temperature is desired1 the whole apparatus is immersed in water contained in the large galvanized tank forming the back-ground of the figures4 ,the tank is seventy-five centimeters long1 seventy-five centimeters high1 and thirty centimeters wide4 ,at one end1 near the top1 is an extension to provide space for heating the fluid in the flasks before introducing the solid in such cases as may be desired4 ,the apparatus is held in place by angle irons soldered to the bottom of the tank and a brace resting against the upright bar bearing the gear-wheels4 ,the water in the tank is heated by injecting steam1 or by burners under the tank4 ,as the tank holds about #cjj pounds of water the work is not subject to sudden changes of temperature1 and little trouble has been experienced in raising and maintaining the temperature of the water1 especially when steam is used4 ,an electric motor1 or a small water-motor with only a very moderate head of water1 will furnish ample power4 #acj4 ,comparison of ,results4--,the following data show the results obtained by the digester as compared with those furnished by the official method1 temperature and time of digestion being the same in each instance4 ,,ammonium ,,citrate ,,solution ,,on ,,phosphates4 ---------------------------------------- --------------------------- ,time ,total ,removed ,removed of phos4 by official by ,substance4 treatment4 acid4 method4 digester4 ,per cent4 ,per cent4 ,per cent4 ---------------------------------------- --------------------------- hour #bg4fg #aj4ei #ad4eb #a 8 #ab4ba #ad4hb #b hours #ad4fa #ag4ef ,steamed bone1 #c 8 #af4dh #ah4ec #e 8 #ag4id #bj4bb #g 8 #ah4ii #bj4be #aj 8 #ai4gc #ba4ah ---------------------------------------- --------------------------- hour #ac4hf #d4dc #d4aa #a 8 #h4bh #f4hb #b hours #aj4cd #i4gf ,marl1 #c 8 #aa4jj #aa4ca #e 8 #aa4hj #aa4hc #h 8 #ab4ea #ab4fd #aj 8 #ab4eh #ac4jj ---------------------------------------- --------------------------- hour #ai4ch #ab4ji #ab4bh #a 8 #ab4dg #ab4dj ,acidulated bone1 #b hours #ab4bj #ab4dc #c 8 #ab4dj #ab4bd #e 8 #ab4dc #ab4bf ---------------------------------------- --------------------------- ,bone1 hour #ba4dj #f4ig #h4dh ,ammoniated dissolved bone1 8 #ah4bb #i4bh #aj4fc ,cottonseed-meal and castor pomace1 8 #b4eb #j4bc #j4be ,phospho bone1 8 #af4ee #g4jf #g4ba ---------------------------------------- --------------------------- ,in comparing duplicates1 the results from the use of the digester are found to be subject to less variation than those from the usual method4 #aca4 ,huston's ,mechanical ,stirrer4--,the stirring apparatus shown in ,fig4 #i differs from those which have heretofore come into use1 in requiring but a single belt to drive all the stirring rods1 and in having all the parts protected from the laboratory fumes4#aai ,the details of the belt system are shown in the small diagram in the lower central part of the figure4 ,the apparatus is mounted on a substantial wooden box1 #bjj centimeters long1 thirty centimeters high1 and eighteen centimeters wide4 ,the driving pulleys1 ten centimeters in diameter1 are enclosed in the upper part of the case4 ,the shafts on which these pulleys are mounted extend through the bottom of the enclosing box and carry a wooden disk1 eleven centimeters in diameter1 to prevent particles of foreign matter from falling into the beakers4 ,the shafts extend two centimeters below these disks1 and to the end of the shafts the bent stirring rods are attached by rubber tubing4 ,the board forming the support of the driving pulleys is extended two centimeters in front of the apparatus1 and in this extension twelve notches are cut1 in which are held the corks carrying the tubes which contain the solution to be used in precipitating the material in the beakers4 ,illustration3 ,,figure #i4 ,,huston',s ,,mechanical ,,stirrer4 ,the ends of these tubes are drawn out to a fine point so as to deliver the liquid at the rate of about one drop per second4 ,the front of the apparatus is hinged and permits the whole to be closed when not in use1 or during the precipitation4 ,the apparatus has proven extremely satisfactory in the precipitation of ammonium magnesium phosphate4 ,the precipitate is very crystalline1 and where the stirring is continued for some minutes1 after the magnesia solution has all been added1 no amorphous precipitate is observed on longer standing4 #acb4 ,the ,citrate ,method ,applied to ,samples with ,small ,content of ,phosphoric ,acid4--,it is well established that the citrate method does not give satisfactory results when applied to samples containing small percentages of phosphoric acid1 especially when these are of an organic nature1 as for instance1 cottonseed cake-meal4 ,in this laboratory attempts have been made to remedy this defect in the process so as to render the use of the method possible even in such cases4#abj ,satisfactory results have been obtained by adding to the solution of the cake-meal a definite volume of a phosphate solution of known strength4 ,solutions of ordinary mineral phosphates are preferred for this purpose4 ,the following example will show the application of the modified method3 ,in a sample of cake-meal1 7cottonseed cake and castor pomace7 the content of phosphoric acid obtained by the molybdate method1 was #b4eb per cent4 ,determined directly by the citrate method1 the following data were obtained3 ,allowing to stand thirty hours after adding magnesia mixture1 #a4jh and #a4ec per cent in duplicates4 ,allowing to stand seventy-two hours after adding magnesia mixture1 #b4ag and #b4cj per cent in duplicates4 ,in each case fifty cubic centimeters of the solution were taken1 representing half a gram of the sample4 ,in another series of determinations twenty-five cubic centimeters of the sample were mixed with an equal volume of a mineral phosphate solution1 the value of which had been previously determined by both the molybdic and citrate methods4 ,the fifty cubic centimeters thus obtained represented a quarter of a gram each of the cake-meal and mineral phosphates4 ,the filtration followed eighteen hours after adding the magnesia mixture4 ,the following data show the results of the determinations3 ,per cent ,per cent ,per cent ,per cent ,p,o in ,p,o in ,p,o ,p,o in mineral organic found in organic phosphate4 sample4 mixture #b4 sample4 #a #ae4cg #b4eb #ag4ij #b4ec #b #bi4af #b4eb #ca4fh #b4eb #c #ca4cg #b4eb #cc4hc #b4de #d #ca4eh #b4eb #cd4bj #b4fb ---- ,mean content of ,p,o in organic sample #b4ec ,it is thus demonstrated that the citrate method can be applied with safety even to the determination of the phosphoric acid in organic compounds where the quantity present is less than three per cent4 ,it is further shown that solutions of mineral phosphates varying in content of phosphoric acid from fifteen to thirty-two per cent may be safely used for increasing the content of that acid to the proper degree for complete precipitation4 ,in cases where organic matters are present they should be destroyed by moist combustion with sulfuric acid as in the determination of nitrogen to be described in the next part4 #acc4 ,direct ,precipitation of the ,citrate-,soluble ,phosphoric ,acid4--,the direct determination of citrate-soluble phosphoric acid by effecting the precipitation by means of magnesia mixture in the solution obtained from the ammonium citrate digestion1 has been practiced for many years by numbers of ,european chemists1 and the process has even obtained a place in the official methods of some ,european countries4 ,various objections have been urged1 however1 against the general employment of this method in fertilizer analysis on account of the inaccuracies in the results obtained in certain cases1 and it has1 therefore1 been used to but a very limited extent in this country4 ,since it is impracticable to effect the precipitation with ammonium molybdate in the presence of citric acid the previous elimination or destruction of this substance has been recognized as essential to the execution of a process involving the separation of the phosphoric acid as phosphomolybdate4 ,it is evident from the data cited in the preceding paragraph1 that great accuracy may be secured in this process by adding a sufficient quantity of a solution of a mineral phosphate and proceeding by the citrate method4 ,ross has also proposed to estimate the acid soluble in ammonium citrate directly by first destroying the organic matter by moist combustion with sulfuric acid4#aba ,he recommends the following process3 ,after completion of the thirty minutes' digestion of the sample with citrate solution1 twenty-five cubic centimeters are filtered at once into a dry vessel4 ,if the liquid be filtered directly into a dry burette1 twenty-five cubic centimeters can be readily transferred to another vessel without dilution4 ,after cooling1 run twenty-five cubic centimeters of the solution into a digestion flask of #bej-cjj cubic centimeters capacity1 add about fifteen cubic centimeters of concentrated sulfuric acid and place the flask on a piece of wire gauze over a moderately brisk flame2 in about eight minutes the contents of the flask commence to darken and foaming begins1 but this will occasion no trouble1 if an extremely high1 or a very low flame be avoided4 ,in about twelve minutes the foaming ceases and the liquid in the flask appears quite black2 about one grain of mercuric oxid is now added and the digestion is continued over a brisk flame4 ,the operation can be completed in less than half an hour with ease1 and in many cases1 twenty-five minutes4 ,after cooling1 the contents of the flask are washed into a beaker1 ammonia is added in slight excess1 the solution is acidified with nitric1 and after the addition of fifteen grams of ammonium nitrate1 the process is conducted as usual4 ,in case as large an aliquot as fifty cubic centimeters of the original filtrate be used1 ten cubic centimeters of sulfuric acid are added1 and the digestion is conducted in a flask of #cjj-ejj cubic centimeters capacity2 after the liquid has blackened and foaming has progressed to a considerable extent1 the flask is removed from the flame1 fifteen cubic centimeters more of sulfuric acid are added1 and the flask and contents are heated at a moderate temperature for two or three minutes2 the mercuric oxid is then added and the operation completed as before described4 ,following are some of the advantages offered by the method described3 7#a7 ,it dispenses with the necessity of the execution of the frequently tedious operation of bringing upon the filter and washing the residue from the ammonium citrate digestion1 while the ignition of this residue together with the subsequent digestion with acid and filtration are also avoided4 7#b7 ,it affords a means for the direct estimation of that form of phosphoric acid which1 together with the water-soluble1 constitutes the available phosphoric acid1 thus enabling the latter to be determined by making only two estimations4 7#c7 ,in connection with the advantages above mentioned it permits of a considerable saving of time1 as well as of labor required in manipulation4 ,in addition to the tests with mercuric oxid1 both potassium nitrate and potassium sulfate were used in the digestion to facilitate oxidation4 ,with the former1 several additions of the salt were necessary to secure a satisfactory digestion1 and even then the time required was longer than with the mercury or mercuric oxid digestion4 ,with potassium sulfate1 the excessive foaming which took place interfered greatly with the execution of the digestion process4 #acd4 ,availability of ,phosphatic ,fertilizers4--,there is perhaps no one question more frequently put to analysts by practical farmers than the one relating to the availability of fertilizing materials4 ,the object of the manufacturer should be to secure each of the valuable ingredients of his goods in the most useful form4 ,the ideal form in which phosphoric acid should come to the soil is one soluble in water4 ,even in localities where heavy rains may abound1 there is not much danger of loss of soluble acid by percolation4 ,as has before been indicated1 the soluble acid tends to become fixed in all normal soils1 and to remain in a state accessible to the rootlets of plants1 and yet free from danger of leaching4 ,for this reason1 by most agronomists1 the water-soluble acid is not regarded as more available than that portion insoluble in water1 yet soluble in ammonium citrate4 ,in many of the ,states the statutes1 or custom1 prescribe that only the water and citrate-soluble acid shall be reckoned as available1 the insoluble residue being allowed no place in the estimates of value4 ,in many instances such a custom may lead to considerable error1 as in the case of finely ground bones and some forms of soft and easily decomposable tricalcium phosphates4 ,there are also1 on the markets1 phosphates composed largely of iron and aluminum salts1 and these appear to have an available value often in excess of the quantities thereof soluble in ammonium citrate4 ,as a rule the apatites1 when reduced to a fine powder and applied to the soil1 are the least available of the natural phosphates4 ,next in order come the land rock and pebble phosphates which1 in most soils1 have only a limited availability4 ,the soft fine-ground phosphates1 especially in soils rich in humus1 have an agricultural value1 almost1 if not quite equal to a similar amount of acid in the acid phosphates4 ,fine-ground bones also tend to give up their phosphoric acid with a considerable degree of readiness in most soils4 ,natural iron and aluminum phosphates1 have also1 as a rule1 a high degree of availability4 ,in each case the analyst must consider all the factors of the case before rendering a decision4 ,not only the relative solubility of the different components of the offered fertilizer in different menstrua must be taken into consideration1 but also the character of the soil to which it is to be applied1 the time of application1 and the crop to be grown4 ,by a diligent study of these conditions the analyst may1 in the end1 reach an accurate judgment of the merits of the sample4 #ace4 ,direct ,weighing of the ,molybdenum ,precipitate4--,it has already been stated that many attempts have1 been made to determine the phosphoric acid by direct weighing as well as by titration1 as in the ,pemberton method4 ,the point of prime importance in such a direct determination is to secure an ammonium phosphomolybdate mixture of constant composition4 ,unless this can be done no direct method1 either volumetric or gravimetric1 can give reliable results4 ,hanamann#abb proposes to secure this constant composition by varying somewhat the composition of the molybdate mixture and precipitating the phosphoric acid under definite conditions4 ,the molybdate solution employed is prepared as follows3 ,molybdic acid #ajj grams4 ,ten per cent ammonia #a4j liter4 ,nitric acid 7#a4bdf sp4 gr47 #a4e liters4 ,the precipitation of the phosphoric acid is conducted in the cold with constant stirring4 ,it is complete in half an hour4 ,the ammonium phosphomolybdate is washed with a solution of ammonium nitrate and then with dilute nitric acid1 dried1 and ignited at less than a red heat4 ,it should then have a bluish-black color throughout4 ,such a body contains #d4jah per cent of phosphoric anhydrid4 ,twenty-five cubic centimeters of a sodium phosphate solution containing fifty milligrams of phosphoric acid1 treated as above1 gave a bluish-black precipitate weighing #a4bdi grams1 which1 multiplied by #j4jdajah1 equaled #ej4jah milligrams of phosphorus pentoxid4 ,the method should be tried on phosphates of various kinds and contents of phosphorus pentoxid before a definite judgment of its merits is formed4 ,,chemistry ,,of ,,the ,,manufacture ,,of ,,superphosphates4 #acf4 ,reactions with ,phosphates4--,in this country the expressions 8acid0 and 8super0 phosphates are used interchangeably4 ,a more correct use of the terms would designate by 8acid0 the phosphate formed directly from tricalcium phosphate by the action of sulfuric acid1 while by 8super0 would be indicated a similar product formed by the action of free phosphoric acid on the same materials4 ,in ,germany the latter compound is called double phosphate4 ,the reaction which takes place in the first instance is represented by the following formula3 #c;,ca7,,po7 #f;,h,,so #ab;,h,o #d;,h,,po ,ca7,,po7 #f7;,ca,s,o#b;,h,o72 and #d;,h,,po ,ca7,,po7 #c;,h,o #c;,ca,h7,,po7,h,o4 ,a simpler form of the reaction is expressed as follows3 ,ca7,,po7 #b;,h,,so #e;,h,o ,ca,h7,,po7,h,o #b;,ca,s,o#b;,h,o4 ,if #caj parts1 by weight1 of fine-ground tricalcium phosphate be mixed with #aif parts of sulfuric acid and ninety parts of water1 and the resulting jelly be quickly diluted with a large quantity of water1 and filtered1 there will be found in the filtrate about three-quarters of the total phosphoric as free acid4 ,if1 however1 the jelly1 at first1 formed as above1 be left to become dry and hard1 the filtrate1 when the mass is beaten up with water and filtered1 will contain monocalcium phosphate1 ,ca,h7,,po74 ,if the quantity of sulfuric acid used be not sufficient for complete decomposition1 the dicalcium salt is formed directly according to the following reaction3 ,ca7,,po7 ,h,,so #f;,h,o ,ca,h7,,po7#d;,h,o ,ca,s,o#b;,h,o4 ,this arises1 doubtless1 by the formation1 at first1 of the regular monocalcium salt and the further reaction of this with the tricalcium compound1 as follows3 ,ca,h7,,po7 ,h,o ,ca7,,po7 #g;,h,o #b;,ca,h7,,po7#d;,h,o4 ,this reaction represents1 theoretically1 the so-called reversion of the phosphoric acid4 ,when there is an excess of sulfuric acid there is a complete decomposition of the calcium salts with the production of free phosphoric acid and gypsum4 ,the reaction is represented by the following formula3 ,ca7,,po7 #c;,h,,so #f;,h,o #b;,h,,po #c;,ca,s,o#b;,h,o4 ,the crystallized gypsum absorbs the six molecules of water in its molecular structure4 #acg4 ,reactions with ,fluorids4--,since calcium fluorid is present in nearly all mineral phosphates1 the reactions of this compound must be taken into consideration in a chemical study of the manufacture of acid phosphates4 ,when treated with sulfuric acid the first reaction which takes place consists in the formation of hydrofluoric acid3 ,ca,f ,h,,so #b;,,hf ,ca,s,o4 ,since1 however1 there is generally some silica in reach of the nascent acid1 all1 or a portion of it1 combines at once with this silica1 forming silicon tetrafluorid3 #d;,,hf ,si,o #b;,h,o ,si,f4 ,this compound1 however1 is decomposed at once in the presence of water1 forming hydrofluosilicic acid3 #c,si,f #b;,h,o ,si,o #b;,h,si,f4 ,the presence of calcium fluorid in natural phosphates is extremely objectionable from a technical point of view1 both on account of the increased consumption of oil of vitriol which it causes1 but also by reason of the injurious nature of gaseous fluorin compounds produced4 ,each #ajj pounds of calcium fluorid entails the consumption of #abe4f pounds of sulfuric acid4 #ach4 ,reaction with ,carbonates4--,most mineral phosphates contain calcium carbonate in varying quantities4 ,this compound is decomposed on treatment with sulfuric acid according to the reaction3 ,ca,c,o ,h,,so ,ca,s,o ,h,o ,,co4 ,when present in moderate amounts1 calcium carbonate is not an objectionable impurity in natural phosphates intended for acid phosphate manufacture4 ,the reaction with sulfuric acid which takes place produces a proper rise in temperature throughout the mass1 while the escaping carbon dioxid permeates and lightens the whole mass1 assisting thus in completing the chemical reaction by leaving the residual mass porous1 and capable of being easily dried and pulverized4 ,where large quantities of carbonate in proportion to the phosphate are present the sulfuric acid used should be dilute enough to furnish the necessary water of crystallization to the gypsum formed4 ,for each #ajj parts1 by weight1 of calcium carbonate1 eighty parts of sulfuric anhydrid are necessary1 or #abe parts of acid of #a4gaj specific gravity #fj ,beaum4 ,in some guanos a part of the calcium is found as pyrophosphate1 and this is acted upon by the sulfuric acid in the following way3 ,ca,p,o ,h,,so ,ca,h,p,o ,ca,s,o4 #aci4 ,solution of the ,iron and ,alumina ,compounds4--,iron may occur in natural phosphates in many forms4 ,it probably is most frequently met with as ferric or ferrous phosphate1 seldom as ferric oxid1 and often as pyrite1 ,fe,s4 ,the iron also may sometimes exist as a silicate4 ,the alumina is found chiefly in combination with phosphoric acid1 and as silicate4 ,where a little less sulfuric acid is employed1 as is generally the case1 than is necessary for complete solution1 the iron phosphate is attacked as represented below3 #c;,fe,p,o #c;,h,,so ,fe,p,o#b;,h,,po ,fe7,,so74 ,when an excess of sulfuric acid is employed1 the formula is reduced to the simple one3 #b;,fe,p,o #c;,h,,so #b;,h,,po ,fe7,,so74 ,a part of the iron sulfate formed reacts with the acid calcium phosphate present to produce a permanent jelly-like compound1 difficult to dry and handle4 ,as much as two per cent of iron phosphate1 however1 may be present without serious interference with the commercial handling of the product4 ,by using more sulfuric acid as much as four or five per cent of the iron phosphate can be held in solution4 ,larger quantities are very troublesome from a commercial point of view4 ,the reaction of the ferric sulfate with monocalcium phosphate1 is as follows3 #c;,ca,h7,,po7 ,fe7,,so7 #d;,h,o #b7;,fe,p,o#b;,h,,po#b;,h,o7 #c;,ca,s,o4 ,pyrite and the silicates containing iron are not attacked by sulfuric acid1 and these compounds are therefore left1 in the final product1 in a harmless state4 ,if the pyritic iron is to be brought into solution aqua regia should be employed4 ,with sufficient acid the aluminum phosphate is decomposed with the formation of aluminum sulfate and free phosphoric acid3 ,al,p,o #c;,h,,so ,al7,,so7 #b;,h,,po4 #adj4 ,reaction with ,magnesium ,compounds4--,the mineral phosphates1 as a rule1 contain but little magnesia4 ,when present it is probably as an acid salt1 ,mg,h,p,o4 ,its decomposition takes place in slight deficiency or excess of sulfuric acid respectively as follows3 #b,mg,h,p ,h,,so #b;,h,o ,mg,h7,,po7#b;,h,o ,mg,s,o and ,mg,h,p,o ,h,,so ,h,,po ,mg,s,o4 ,the magnesia1 when in the form of oxid1 is capable of producing a reversion of the monocalcium phosphate1 as is shown below3 ,ca,h7,,po7 ,mg,o ,ca,mg,h7,,po7 ,h,o4 ,one part by weight of magnesia can render three and one-half parts of soluble monocalcium phosphate insoluble4 #ada4 ,determination of ,quantity of ,sulfuric ,acid ,necessary for ,solution of a ,mineral ,phosphate4--,the theoretical quantity of sulfuric acid required for the proper treatment of any phosphate may be calculated from its chemical analysis and by the formulas and reactions already given4 ,for the experimental determination the method of ,rmpler may be followed4#abc ,twenty grams of the fine phosphate are placed in a liter flask with a greater quantity of accurately measured sulfuric acid than is necessary for complete solution4 ,the acid should have a specific gravity of #a4dee or #de ,b4 ,the mixture is allowed to stand for two hours at #ej4 ,it is then cooled1 the flask filled with water to the mark1 well shaken1 and the contents filtered4 ,fifty cubic centimeters of the filtrate are treated with tenth normal soda-lye until basic phosphate begins to separate4 ,the excess of acid used is then calculated4 ,example3 ,twenty grams of phosphate containing #bh4c per cent of phosphoric acid1 #aj4j per cent of calcium carbonate1 #e4e per cent of calcium fluorid1 and #b4d per cent of calcium chlorid were treated as above with sixteen cubic centimeters of sulfuric acid containing #aj4bd grams of sulfur trioxid4 ,in titrating fifty cubic centimeters of the filtrate obtained as described above1 #aj4d cubic centimeters of tenth normal soda-lye were used1 equivalent to #j4jdaf gram of sulfur trioxid4 ,then #aj4bd #ej #ajjj #j4eabj total sulfur trioxid in fifty cubic centimeters of the filtrate1 and #j4eabj - #j4jdaf #j4dgjd gram1 the amount of sulfur trioxid consumed in the decomposition4 ,therefore the sulfur trioxid required for decomposition is #dg4jd per cent of the weight of the phosphate employed4 ,one hundred parts of the phosphate would therefore require #dg4jd parts of sulfur trioxid to #gc4f parts of sulfuric acid of #a4gaj specific gravity or #ib4a parts of #a4ecj specific gravity4 ,a more convenient method than the one mentioned above consists in treating a small quantity of the phosphate1 from one-half to one kilogram1 in the laboratory1 or fifty kilograms in a lead box1 just as would be practiced on a large scale4 ,a few tests with these small quantities1 followed by drying and grinding will reveal to the skilled operator the approximate quantity and strength of sulfuric acid to be used in each case4 ,the quantities of sulfuric acid as determined by calculation from analyses and by actual laboratory tests agree fairly well in most instances4 ,there is1 however1 sometimes a marked disagreement4 ,the general rule of practice is to use always an amount of sulfuric acid sufficient to produce and maintain water-soluble phosphoric acid in the fertilizer1 but the sulfuric acid must not be used in such quantity as to interfere with the subsequent drying1 grinding1 and marketing of the acid phosphate4 ,for convenience the following table may be used for calculating the quantity of oil of vitriol needed for each unit of weight of material noted3 ,,one ,,part ,,by ,,weight ,,of ,,each ,,substance ,,below ,,requires3 ,,sulfuric ,,acid ,,by ,,same ,,unit ,,of ,,weight4 ,at #dh ,at #ej ,at #eb ,at #ed ,at #ee ,b4 ,b4 ,b4 ,b4 ,b4 ,tricalcium phosphate #a4eij #a4eag #a4ddf #a4chb #a4ceb ,iron phosphate #a4fcj #a4eeh #a4dhe #a4dbj #a4cij ,aluminum phosphate #b4jbe #a4icj #a4hci #a4gef #a4gba ,calcium carbonate #a4fdj #a4efe #a4die #a4dbh #a4daa ,calcium fluorid #b4jjf #b4jaj #a4iaf #a4hcj #a4gid ,magnesium carbonate #a4idj #a4hfj #a4gge #a4fij #a4ffj ,example4--,suppose for example a phosphate of the following composition is to be treated with sulfuric acid2 viz41#abd ,moisture and organic #d4jj per cent4 ,calcium phosphate #ee4jj 8 ,calcium carbonate #c4jj 8 ,iron and aluminum phosphate nearly all alumina #f4ej 8 ,magnesium carbonate #j4ge 8 ,calcium fluorid #b4be 8 ,insoluble #bh4jj 8 ,using sulfuric acid of #ej ,b41 the following quantities will be required for each #ajj kilograms4 ,kilos of acid required4 ,calcium phosphate1 fifty-five kilos #hc4dd 8 carbonate three and a half kilos #e4dh 8 fluorid1 two and a quarter 8 #d4eb ,aluminum and iron phosphate1 six and a half kilos #ab4ee ,magnesium carbonate1 three-quarters of a kilo #a4dj ----- ,total #ajg4ci #adb4 ,phosphoric ,acid ,superphosphates4--,if a mineral phosphate be decomposed by free phosphoric in place of sulfuric acid the resulting compound will contain about three times as much available phosphoric acid as is found in the ordinary acid phosphate4 ,the reaction takes place according to the following formulas3 7#a7 ,ca7,,po7 #d;,h,,po #c;,h,o #c;,,cah7,,po7,h,o4 7#b7 ,ca7,,po7 #b;,h,,po #ab;,h,o #c;,ca,h7,,po7#d;,h,o4 ,in each case the water in the final product is probably united as crystal water with the calcium salts produced4 ,the monocalcium salt formed in the first reaction is soluble in water and the dicalcium salt in the second reaction in ammonium citrate4 ,where fertilizers are to be transported to great distances there is a considerable saving of freight by the use of such a high-grade phosphate1 which may1 at times1 contain over forty per cent of available acid4 ,the phosphoric acid used is made directly from the mineral phosphate by treating it with an excess of sulfuric acid4 ,,authorities ,,cited ,,in ,,part ,,first4 #a ,day1 ,mineral ,resources of the ,united ,states #aic1 pp4 #gjc1 et seq4 #b ,massachusetts ,agricultural ,experiment ,station1 ,bulletin #ea1 ,march1 #ahid4 #c ,brown1 ,manual of ,assaying1 p4 #bd4 #d ,bulletin de l',association des ,chimistes de ,sucrrie1 ,no4 #b1 pp4 #g1 et seq4 #e ,proceedings of the ,twelfth and ,thirteenth ,meetings of the ,society for the ,promotion of ,agricultural ,science1 p4 #adj4 #f ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin #dc1 p4 #cda4 #g ,rapport adress par le ,comit des ,stations agronomiques au sujet des ,methodes suivre dans l',analyse des ,matires fertilisantes4 #h ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #ch1 ,s4 #cjc4 #i ,vid4 op4 cit4 #f1 p4 #cda4 #aj ,zeitschrift fr analytische ,chemie1 #ahij1 ,s4 #cij4 #aa ,vid4 op4 cit4 #f1 p4 #cdb4 #ab ,chemisches ,centralblatt1 ,band #b1 ,s4 #hac4 #ac ,transactions of the ,american ,institute of ,mining ,engineers1 ,vol4 #ba1 p4 #afe4 #ad ,phosphates of ,america1 p4 #add4 #ae ,vid4 op4 et loc4 cit4 #ac4 #af ,u4 ,s4 ,geological ,survey1 ,bulletin ,no4 #dg4 #ag ,vid4 op4 et loc4 cit4 #ad4 #ah ,vid4 op4 et loc4 cit4 #ac4 #ai ,vid4 op4 cit4 #ad1 p4 #adg4 #bj ,transactions of the ,american ,institute of ,mining ,engineers1 ,vol4 #ba1 p4 #afh4 #ba ,phosphates of ,america1 p4 #aec4 #bb ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #cd1 ,s4 #cgi4 #bc ,zeitschrift fr analytische ,chemie1 #ahib1 ,s4 #chc4 #bd ,zeitschrift fr angewandte ,chemie1 #ahid1 ,ss4 #fgi und #gja4 #be ,vid4 op4 cit4 supra1 #ahhi1 p4 #fcf4 #bf ,vid4 op4 cit4 #bd1 #ahia1 p4 #c4 #bg ,rapports presentes au ,congrs ,international de ,chimie ,appliqu1 ,bruxelles1 ,aot1 #ahid1 p4 #bf4 #bh ,vid4 op4 et loc4 cit4 #bj4 #bi ,le ,stazioni ,sperimentali ,agrarie ,italiane1 ,vol4 #bc1 p4 #ca4 #cj ,crookes' ,select ,methods1 p4 #ech4 #ca ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #e1 p4 #fga4 ,for additional authorities on these methods consult ,meyer and ,wohlrab1 ,zeitschrift fr angewandte ,chemie1 #ahia1 ,ss4 #agj und #bdc4 ,gruber1 ,zeitschrift fr analytische ,chemie1 ,band #cj1 ,s4 #bjf4 ,shephard1 ,chemical ,news1 ,may #bi1 #ahia1 p4 #bea4 ,vgel1 ,zeitschrift fr angewandte ,chemie1 #ahia1 ,band #ab1 ,s4 #ceg4 #cb ,journal of the ,american ,chemical ,society1 ,april1 #ahie4 #cc ,vid4 op4 cit4 #ba1 p4 #aej4 #cd ,transactions of the ,american ,institute of ,mining ,engineers1 ,vol4 #ba1 p4 #agj4 #ce ,vid4 op4 cit4 supra1 p4 #agc4 #cf ,comptes rendus1 ,tome #ed1 p4 #dfh4 #cg ,crookes' ,select ,methods1 p4 #ejj4 #ch ,for details of method see ,fresenius quantitative ,analysis4 #ci ,u4 ,s4 ,department of ,agriculture1 ,chemical ,division1 ,bulletin #dc1 p4 #cda4 #dj ,letter to ,b4 ,w4 ,kilgore1 ,reporter for ,phosphoric ,acid to the ,association of ,official ,agricultural ,chemists4 #da ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #ch1 ,s4 #cjd4 #db ,communicated by ,dr4 ,solberg4 #dc ,from the ,official ,swedish ,methods2 translated for the author by ,f4 ,w4 ,woll4 #dd ,methoden van ,onderzock aan de ,rijkslandbouw-proefstations1 #ahic1 p4 #d4 #de ,zeitschrift fr analytische ,chemie1 #ahic1 ,s4 #fd4 #df ,journal of the ,american ,chemical ,society1 ,vol4 #af4 #dg ,zeitschrift fr angewandte ,chemie1 #ahid1 ,s4 #fgh4 #dh ,journal fr ,landwirtschaft1 ,band #cj1 ,s4 #bc4 #di ,vid4 op4 cit4 #dg1 p4 #edd4 #ej ,vid4 op4 cit4 #df1 ,vol4 #af1 p4 #dfb4 #ea ,vid4 op4 et loc4 cit4 supra4 #eb ,die ,agricultur-,chemische ,versuchs-,station1 ,halle a_/,s41 ,ss4 #ef1 et seq4 #ec ,chemische ,industrie1 #ahij4 #ed ,vid4 op4 et loc4 cit4 #eb4 #ee ,chemiker ,zeitung1 #ahij1 ,no4 #ge1 ,s4 #abdf4 #ef ,vid4 op4 cit4 #dc4 #eg ,glaser1 ,zeitschrift fr analytische ,chemie1 #bd1 #agh 7#ahhe74 ,laubheimer1 ,ibid1 #be1 #daf 7#ahhf74 ,mller1 ,tagebl4 d4 ,naturforscher-,vers4 zu ,wiesbaden1 #ahhf1 #cfe4 ,vgel1 ,chemiker ,zeitung1 #ahhh1 #he4 ,stutzer1 ,ibid1 #dib4 ,seifert1 ,ibid1 #acij4 v4 ,reis1 ,zeitschrift fr angewandte ,chemie1 #ahhh1 #ced4 ,loges1 ,reportorium fr analytische ,chemie1 #g1 #he 7#ahhg74 ,kassuer1 ,zeitschrift fr ,nahrungsmitteluntersuchung und ,hygiene1 #b1 #bb 7#ahhh74 ,c4 ,mller1 ,die ,landwirtschaftlichen ,versuchs-,stationen1 #ce1 #dch 7#ahhh74 #eh ,l',engrais1 ,tome #i1 p4 #ibh4 #ei ,vid4 op4 et loc4 cit4 #dd4 #fj ,journal of the ,american ,chemical ,society1 ,vol4 #af1 p4 #dfb4 #fa ,die ,landwirtschaftlichen ,versuchs-,stationen1 ,band #da1 ,s4 #cbi4 #fb ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #e1 p4 #fhe4 #fc ,vid4 op4 cit4 supra1 ,vol4 #c1 p4 #dac4 #fd ,zeitschrift fr angewandte ,chemie1 #ahhf1 ,s4 #ced4 #fe ,vid4 op4 cit4 #eb1 p4 #fa4 #ff ,vid4 op4 cit4 #ee1 ,vol4 #ah1 p4 #aaec4 #fg ,chemiker ,zeitung1 #ahid1 ,no4 #hh1 p4 #aicd4 #fh ,op4 cit4 supra1 #ahib1 p4 #adga4 #fi ,vid4 op4 cit4 #fj1 p4 #gba4 #gj ,zeitschrift fr analytische ,chemie1 ,band #bi1 ,s4 #djh4 #ga ,mitteilungen der deutschen ,landwirtschafts ,gesellschaft1 #ahij-'ia1 ,no4 #aa1 ,s4 #aca4 #gb ,zeitschrift fr angewandte ,chemie1 #ahhh1 ,s4 #bii4 #gc ,vid4 op4 cit4 #gj1 p4 #dji4 #gd ,vid4 op4 cit4 #gb1 #ahij1 p4 #eie4 #ge ,vid4 op4 cit4 #fa1 ,tome #dc1 p4 #ahc4 #gf ,chemiker ,zeitung1 ,band #ah1 ,s4 #efe4 #gg ,chemical ,news1 ,vol4 #a1 p4 #ig4 #gh ,archive fr ,wissenschaftliche ,heilkunde1 ,band #d1 ,s4 #bbh4 #gi ,journal fr praktische ,chemie1 ,band #gj1 ,s4 #ajd4 #hj ,sutton's ,volumetric ,analysis1 p4 #bcg4 #ha ,bulletin de la ,socit des ,agriculteurs de ,france1 #ahgf1 p4 #ec4 #hb ,manual ,agenda des ,fabricants de ,sucre1 #ahhi1 p4 #cjg4 #hc ,journal of the ,american ,chemical ,society1 ,vol4 #ae1 p4 #chb1 and ,vol4 #af1 p4 #bgh4 #hd ,chemical ,news1 ,vol4 #dg1 p4 #abg4 #he ,american ,chemical ,journal1 ,vol4 #aa1 p4 #hd4 #hf ,vid4 op4 cit4 #hc1 ,vol4 #af1 p4 #bhb4 #hg ,bulletin #dc1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #hh4 #hh ,vid4 op4 cit4 supra1 p4 #ia4 #hi ,repertoire de ,pharmacie1 #ahic1 p4 #aec4 #ij ,revue de ,chimie ,analytique ,appliqu1 #ahic1 p4 #aac4 #ia ,chemiker ,zeitung1 #ahid1 ,s4 #aecc4 #ib ,blair1 ,analysis of ,iron and ,steel1 p4 #ie4 #ic ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #g1 p4 #ajh4 #id ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #abi4 #ie ,vid4 op4 cit4 #ib1 p4 #ii4 #if ,eighth ,annual ,report of ,purdue ,university1 p4 #bch4 #ig ,receuil des ,travaux ,chimiques1 ,tome #ab1 pp4 #a1 et seq4 ,journal of the ,chemical ,society 7,abstracts71 ,vol4 #fd1 p4 #dif4 #ih ,zeitschrift fr angewandte ,chemie1 #ahia1 ,ss4 #bgi1 et seq4 #ii ,le ,stazioni ,sperimentali ,agrarie ,italiane1 ,february1 #ahia4 #ajj ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #dc4 #aja ,vid4 op4 et loc4 cit4 supra4 #ajb ,l',engrais1 ,tome #aj1 p4 #fe4 #ajc ,journal of ,analytical and ,applied ,chemistry1 ,vol4 #e1 p4 #fid4 ,zeitschrift fr analytische ,chemie1 ,band #ah1 ,s4 #ii4 #ajd ,vid4 op4 cit4 #ib1 p4 #ajc4 #aje ,journal of the ,chemical ,society 7,abstracts71 ,vol4 #eh1 p4 #acdc4 #ajf ,comptes rendus1 ,tome #aad1 p4 #aahi4 #ajg ,vid4 op4 cit4 #bd and #be4 #ajh ,report communicated to author by ,w4 ,g4 ,brown4 #aji ,chemisches ,centralblatt1 #ahie1 p4 #efb4 #aaj ,wiley1 ,report on ,fertilizers to ,indiana ,state ,board of ,agriculture1 #ahhb4 #aaa ,proceedings of the ,association of ,official ,agricultural ,chemists1 ,atlanta1 #ahhd1 p4 #ai4 ,report of ,indiana ,state ,board of ,agriculture1 #ahhb1 p4 #bcj1 and ,proceedings of the ,association of ,official ,agricultural ,chemists1 ,atlanta1 #ahhd1 p4 #cj4 ,huston and ,jones4 7,these gentlemen are now investigating all materials used as sources of phosphoric acid in fertilizers2 their results here quoted are from unpublished work1 and include but a small part of the work so far done47 ,american ,chemical ,journal1 ,march1 #ahhd1 p4 #a4 ,proceedings of the ,association of ,official ,agricultural ,chemists1 ,atlanta1 #ahhd1 p4 #bc4 ,ibid1 p4 #bh4 ,ibid1 p4 #ch4 ,ibid1 p4 #de4 ,u4 ,s4 ,department of ,agriculture1 ,chemical ,division1 ,bulletin ,no4 #g1 p4 #ah4 ,ibid1 ,bulletin ,no4 #bh1 p4 #aga4 ,ibid1 ,bulletin ,no4 #ca1 p4 #ajj4 ,ibid1 ,bulletin ,no4 #ca1 p4 #ii4 #aab ,manuscript communication to author4 #aac ,pamunky phosphate is the so-called 8olive earth0 found along the ,pamunky river1 in ,virginia4 ,it is almost all precipitated iron and aluminum phosphates1 and the product is peculiar in that the iron is almost all in the ferrous condition4 #aad ,in the work of ,t4 ,s4 ,gladding only fifty cubic centimeters of citrate were used4 #aae ,in the work of ,t4 ,s4 ,gladding only fifty cubic centimeters of citrate were used4 #aaf ,zeitschrift fr analytische ,chemie1 ,band #aj1 ,s4 #acc4 #aag ,lehrbuch der ,dngerfabrication4 #aah ,bulletin #ed1 ,purdue ,agricultural ,experiment ,station1 p4 #d4 #aai ,vid4 op4 cit4 supra1 p4 #g4 #abj ,runyan and ,wiley2 ,paper presented to ,washington ,section of the ,american ,chemical ,society1 ,april #aa1 #ahie4 #aba ,bulletin #ch1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #af4 #abb ,chemiker ,zeitung1 #ahie1 ,s4 #eec4 #abc ,die ,kuflichen ,dungermittel ,stoffe1 dritte ,auflage1 #ahhi4 #abd ,wyatt1 ,phosphates of ,america1 p4 #abh4 ,,part ,,second4 ,,nitrogen ,,in ,,fertilizers4 #adc4 ,kinds of ,nitrogen in ,fertilizers4--,nitrogen is the most costly of the essential plant foods4 ,it has been shown in the first volume1 paragraph #bc1 that the popular notion regarding the relatively great abundance of nitrogen is erroneous4 ,it forms only #j4jb per cent of the matter forming and pertaining to the earth's crust4 ,the great mass of nitrogen forming the bulk of the atmosphere is inert and useless in respect of its adaptation to plant food4 ,it is not until it becomes oxidized by combustion1 electrical discharges1 or the action of certain microorganisms that it assumes an agricultural value4 ,having already1 in the first volume1 described the relation of nitrogen to the soil it remains the sole province of the present part to study it as aggregated in a form suited to plant fertilization4 ,in this function nitrogen may claim the attention of the analyst in the following forms3 #a4 ,in organic combination in animal or vegetable substances1 forming a large class of bodies1 of which protein may be taken as the type4 ,dried blood or cottonseed-meal illustrates this form of combination4 #b4 ,in the form of ammonia or combinations thereof1 especially as ammonium sulfate1 or as amid nitrogen4 #c4 ,in a more highly oxidized form as nitrous or nitric acid usually united with a base of which ,chile saltpeter may be taken as a type4 ,the analyst has often to deal with single forms of nitrogenous compounds1 but in many instances may also find all the typical forms in a single sample4 ,among the possible cases which may arise the following are types3 a4 ,the sample under examination may contain nitrogen in all three forms mentioned above4 b4 ,there may be present nitrogen in the organic form mixed with nitric nitrogen4 c4 ,ammoniacal nitrogen may replace the nitric in the above combination4 d4 ,the sample may contain no organic but only nitric and ammoniacal nitrogen4 e4 ,only nitric or ammoniacal nitrogen may be present4 #add4 ,determination of the ,state of ,combination4--,some of the sample is mixed with a little powdered soda-lime4 ,if ammoniacal nitrogen be present free ammonia is evolved even in the cold and may be detected either by its odor or by testing the escaping gas with litmus or turmeric paper4 ,a glass rod moistened with strong hydrochloric acid will produce white fumes of ammonium chlorid when brought near the escaping ammonia4 ,if the sample contain any notable amount of nitric acid it will be revealed by treating an aqueous solution of it with a crystal of ferrous sulfate and strong sulfuric acid4 ,the iron salt should be placed in a test-tube with a few drops of the solution of the fertilizer and the sulfuric acid poured down the sides of the tube in such a way as not to mix with the other liquids4 ,the tube must be kept cold4 ,a dark brown ring will mark the disk of separation between the sulfuric acid and the aqueous solution in case nitric acid be present4 ,if water produce a solution of the sample too highly colored to be used as above1 alcohol of eighty per cent strength may be substituted4 ,the coloration produced in this case is of a rose or purple tint4 ,nitric nitrogen may also be detected by means of brucin4 ,if a few drops of an aqueous solution of brucin be mixed with the same quantity of an aqueous extract of the sample under examination and strong sulfuric acid be added1 as described above1 there will be developed at the disk of contact between the acid and the mixed solutions a persistent rose tint varying to yellow4 ,to detect the presence of organic albuminoid nitrogen the residue insoluble in water1 when heated with soda-lime1 will give rise to ammonia which may be detected as described above4 #ade4 ,microscopic ,examination4--,if the chemical test reveal the presence of organic nitrogen the next point to be determined is the nature of the substance containing it4 ,often this is revealed by simple inspection1 as in the case of cottonseed-meal4 ,frequently1 however1 especially in cases of fine-ground mixed goods1 the microscope must be employed to determine the character of the organic matter4 ,it is important to know whether hair1 horn1 hoof1 and other less valuable forms of nitrogenous compounds have been substituted for dried blood1 tankage1 and more valuable forms4 ,in most cases the qualitative chemical1 and microscopic examination will be sufficient4 ,there may be cases1 however1 where the analyst will be under the necessity of using other means of identification suggested by his skill and experience or the circumstances connected with any particular instance4 ,in such cases the general appearance1 odor1 and consistence of the sample may afford valuable indications which will aid in discovering the origin of the nitrogenous materials4 ,,sources ,,of ,,nitrogenous ,,fertilizers4 #adf4 ,seeds and ,seed ,residues4--,the proteid matters in seeds and seed residues1 after the extraction of the oil1 are highly prized as sources of nitrogenous fertilizers either for direct application or for mixing4 ,typical of this class of substances is cottonseed-meal1 the residue left after the extraction of the oil which is accomplished at the present time mostly by hydraulic pressure4 ,the residual cakes contain still some oil but nearly half their weight consists of nitrogenous compounds4 ,the following table gives the composition of a sample of cottonseed-meal3 ,ash #g4fj per cent4 ,fiber #d4ij 8 ,oil #aj4ja 8 ,protein #ea4ab 8 ,digestible carbohydrates1 etc4 #bf4cg 8 ,while the above shows the composition of a single sample of the meal it should be remembered that there may be wide variations from this standard due either to natural composition or to different degrees of the extraction of the oil4 ,the composition of the ash is given below3 ,phosphoric acid1 ,p,o #ca4ja per cent4 ,potash1 ,k,o #ce4ej 8 ,soda1 ,na,o #j4eg 8 ,lime1 ,ca,o #e4fh 8 ,magnesia1 ,mg,o #ae4ai 8 ,sulfuric acid1 ,,so #c4ij 8 ,insoluble1 #j4fi 8 ,carbon dioxid and undetermined1 #g4df 8 ,the cakes left after the expression of the oil from flaxseed and other oily seeds are also very rich in nitrogenous matters2 but these residues are chiefly used for cattle-feeding and only the undigested portions of them pass into the manure4 ,cottonseed cake-meal is not so well suited for cattle-feeding as the others mentioned1 because of the cholin and betan which it contains2 often in sufficient quantities to render its use dangerous to young animals4 ,the danger in feeding increases as the total quantity of the two bases and also as the relative quantity of cholin to betan1 the former base being more poisonous than the latter4 ,in a sample of the mixed bases prepared in this laboratory from cottonseed cake-meal the cholin amounted to #ag4e and the betan to #hb4e per cent of the whole4#abe ,the nitrogen contained in these bases is also included in the total nitrogen found in the meal4 ,the actual proteid value of the numbers obtained for nitrogen is therefore less than that obtained for the whole of the nitrogen by the quantity present as nitrogenous bases4 ,in the ,united ,states cottonseed cake-meal is used in large quantities as a direct fertilizer but not so extensively for mixing as some of the other sources of nitrogen4 ,its delicate yellow color serves to distinguish it at once from the other bodies used for similar purposes4 ,no special mention need be made of other oil-cake residues4 ,they are quite similar in their composition and uses1 and manner of treatment and analysis to the cottonseed product4 #adg4 ,fish ,scrap4--,certain species of fish1 such as the menhaden1 are valued more highly for their oil and refuse than for food purposes4 ,but even where fish in large quantities are prepared for human food1 there is a considerable quantity of waste matter which is valuable for fertilizing purposes4 ,the residue of fish from which the fat and oil have been extracted1 is dried and ground for fertilizing uses4 ,the fish scrap thus obtained is used extensively1 especially on the ,atlantic border of the ,united ,states1 for furnishing the nitrogenous ingredient in mixed fertilizers1 and also for direct application to the fields4 ,in fish flesh deprived of oil and water1 the content of phosphoric acid is about two and one-half per cent1 while the proteid matter may amount to three-quarters of the whole4#abf ,the use of fish for fertilizing purposes is not new4 ,as early as #afba the settlers at ,plymouth were taught to fertilize their maize fields by ,squanto1 an ,indian4 ,according to ,goode1 the value of nitrogen derived from the menhaden alone was two million dollars in #ahge4abg ,in #ahgh it is estimated that #bjj1jjj tons of these fish were captured between ,cape ,henry and the ,bay of ,fundy4 ,the use of fish scrap for nitrogenous fertilizing has1 since then1 become an established industry1 and the analyst may well examine his samples for this source of nitrogen when they are manufactured at points on the ,atlantic coast1 in proximity to great fishing centers4 #adh4 ,dried ,blood and ,tankage4--,the blood and dbris from abattoirs afford abundant sources of nitrogen in a form easily oxidized by the microorganisms of the soil4 ,blood is prepared for use by simple drying and grinding4 ,the intestines1 scraps1 and fragments of flesh resulting from trimming and cutting1 are placed in tanks and steamed under pressure to remove the fat4 ,the residue is dried and ground1 forming the tankage of commerce4 ,dried blood is richer in proteid matter than any other substance in common use for fertilizing purposes4 ,when in a perfectly dry state1 it may contain as much as fourteen per cent of nitrogen1 equivalent to nearly eighty-eight per cent of proteid or albuminoid matter4 ,tankage is less rich in nitrogen than dried blood1 but still contains enough to make it a highly desirable constituent of manures4 ,naturally1 it would vary more in its nitrogen content than dried blood4 #adi4 ,horn1 ,hoof1 and ,hair4--,these bodies1 although quite rich in nitrogen1 are not well suited to fertilizing purposes on account of the extreme slowness of their decomposition4 ,their presence1 therefore1 should be regarded in the nature of a fraud1 because by the usual methods of analysis they show a high percentage of nitrogen1 and therefore acquire a fictitious value4 ,the relative value of the nitrogen in these bodies as compared with the more desirable forms1 is given in paragraph #e4 #aej4 ,ammoniacal ,nitrogen4--,in ammonia compounds1 nitrogen is used chiefly for fertilizing purposes as sulfate4 ,the ideal nitrogenous fertilizer would be a combination of the ammoniacal and nitric nitrogen found in ammonium nitrate4 ,the high cost of this substance excludes its use except for experimental purposes4 #aea4 ,nitrogen in ,guanos4--,the nitrogen in guanos may be found partly as organic1 partly as ammoniacal1 and partly as nitric nitrogen4 ,the high manurial value of guanos and bat deposits in caves1 is due not only to their phosphoric acid1 but also to the fact that part of the nitrogen is immediately available1 while a part becomes assimilable by nitrification during the growing season4 ,the content of nitrogen in guanos is extremely variable1 and depends largely on the climatic conditions to which the deposit has been subjected4 ,the state in which it exists is also a variable one1 but with a constant tendency to assume finally the nitric condition4 ,the well-known habits of birds in congregating in rookeries during the nights1 and at certain seasons of the year1 tend to bring into a common receptacle the nitrogenous matters which they have gathered and which are deposited in their excrement and in the decay of their bodies4 ,the feathers of birds are particularly rich in nitrogen1 and the nitrogenous content of the flesh of fowls is also high4 ,the decay therefore1 of remains of birds1 especially if it take place largely excluded from the leaching of water1 tends to accumulate vast deposits of nitrogenous matter4 ,if the conditions in such deposits be favorable to the processes of nitrification1 the whole of the nitrogen1 or at least the larger part of it1 which has been collected in this dbris1 becomes finally converted into nitric acid1 and is found combined with appropriate bases as deposits of nitrates4 ,the nitrates of the guano deposits1 and of the deposits in caves1 arise in this way4 ,if these deposits be subject to moderate leaching1 the nitrate may become infiltered into the surrounding soil1 making it very rich in this form of nitrogen4 ,the beds and surrounding soils of caves are often found highly impregnated with nitrates4 ,while for our purpose1 deposits of nitrates only are to be considered which are of sufficient value to bear transportation1 yet much interest attaches to the formation of nitrates in the soil even when they are not of commercial importance4 ,in many soils of tropical regions not subject to heavy rainfalls1 the accumulation of these nitrates is very great4 ,mntz and ,marcano#abh have investigated many of these soils1 to which attention was called first by ,humboldt and ,boussingault4 ,they state that these soils are incomparably more rich in nitrates than the most fertile soils of ,europe4 ,the samples which they examined were collected from different parts of ,venezuela and from the valleys of the ,orinoco1 as well as on the shore of the ,sea of ,antilles4 ,the nitrated soils are very abundant in this region of ,south ,america1 where they cover large surfaces4 ,their composition is variable1 but in all of them calcium carbonate and phosphate are met with1 and organic nitrogenous material4 ,the nitric acid is found always combined with lime4 ,in some of the soils as high as thirty per cent of calcium nitrate have been found4 ,nitrification of organic material takes place very rapidly the year round in this tropical region4 ,these nitrated soils are everywhere abundant around caves1 as described by ,humboldt1 which serve as the refuge of birds and bats4 ,the nitrogenous matters1 which come from the decay of the remains of these animals1 form true deposits of guano1 which are gradually spread around1 and which1 in contact with the limestone and with access of air1 suffer complete nitrification with the fixation of the nitric acid by the lime4 ,large quantities of this guano are also due to the dbris of insects1 fragments of elytra1 scales of the wings of butterflies1 etc41 which are brought together in those places by the millions of cubic meters4 ,the nitrification1 which takes place in these deposits1 has been found to extend its products to a distance of several kilometers through the soil4 ,in some places the quantity of calcium nitrate is so great in the soils that they are converted into a plastic paste by this deliquescent salt4 #aeb4 ,nitric ,nitrogen4--,in its purer forms1 and suited to manurial purposes1 nitric acid exists in combination with sodium as a compound commonly known as ,chile saltpeter4 ,the existence of these nitrate deposits has long been known4#abi ,the old ,indian laws originally prohibited the collection of the salt1 but nevertheless it was secretly collected and sold4 ,up to the year #ahba1 soda saltpeter was not known in ,europe except as a laboratory product4 ,about this time the naturalist1 ,mariano de ,rivero1 found on the ,pacific coast1 in the ,province of ,tarapac1 immense new deposits of the salt4 ,later the salt was found in equal abundance in the ,territory of ,antofagasta1 and further to the south in the desert of ,atacama1 which forms the ,department of ,taltal4 ,at the present time the collection and export of saltpeter from ,chile is a business of great importance4 ,the largest export which has ever taken place in one year was in #ahij1 when the amount exported was #ibg1bij1dcj kilograms2 of this quantity #fdb1ejf1ihe kilograms were sent to ,england and #hf1abd1hgj kilograms to the ,united ,states4 ,since that time the imports of this salt into the ,united ,states have largely increased4 ,according to ,pissis#acj these deposits are of very ancient origin4 ,this geologist is of the opinion that the nitrate deposits are the result of the decomposition of feldspathic rocks1 the bases thus produced gradually becoming united with the nitric acid provided from the air4 ,according to the theory of ,nllner#aca the deposits are of more modern origin1 and due to the decomposition of marine vegetation4 ,continuous solution of soils beneath the sea gives rise to the formation of great lakes of saturated water1 in which occurs the development of much marine vegetation4 ,on the evaporation of this water1 due to geologic isolation1 the decomposition of nitrogenous organic matter causes generation of nitric acid1 which1 coming in contact with the calcareous rocks1 attacks them1 forming calcium nitrate1 which1 in presence of sodium sulfate1 gives rise to a double decomposition into sodium nitrate and calcium sulfate4 ,the fact that iodin is found in greater or less quantity in ,chile saltpeter is one of the chief supports of this hypothesis of marine origin1 inasmuch as iodin is always found in sea plants1 and not in terrestrial plants4 ,further than this1 it must be taken into consideration that these deposits of sodium nitrate contain neither shells nor fossils1 nor do they contain any calcium phosphate4 ,the theory1 therefore1 that they are due to animal origin is scarcely tenable4 ,lately extensive nitrate deposits have been discovered in the ,u4 ,s4 of ,columbia4#acb ,these deposits have been found extending over thirty square miles and vary in thickness from one to ten feet4 ,the visible supply is estimated at #g1cgb1hjj1jjj tons1 containing from #a4j to #ac4e percent of nitrate4 ,the deposits consist of a mixture of sodium nitrate1 sodium chlorid1 calcium sulfate1 aluminum sulfate1 and insoluble silica4 ,it is thought that the amount of these deposits will almost equal those in ,chile and ,peru4 ,,methods ,,of ,,analysis4 #aec4 ,classification of ,methods4--,in general there are three direct methods of determining the nitrogen content of fertilizers4 ,first the nitrogen may be secured in a gaseous form and the volume thereof1 under standard conditions1 measured and the weight of nitrogen computed4 ,this process is commonly known as the absolute method4 ,practically it has passed out of use in fertilizer work1 or is practiced only as a check against new and untried methods1 or on certain nitrogenous compounds which do not readily yield all their nitrogen by the other methods4 ,the process1 first perfected by ,dumas1 who has also given it his name1 consists in the combustion of the nitrogenous body in an environment of copper oxid by which the nitrogen1 by reason of its inertness1 is left in a gaseous state after the oxidation of the other constituents2 viz41 carbon and hydrogen1 originally present4 ,in the second class of methods the nitrogen is converted into ammonia which is absorbed by an excess of standard acid1 the residue of which is determined by subsequent titration with a standard alkali4 ,there are two distinct processes belonging to this class1 in one of which ammonia is directly produced by dry combustion of an organic nitrogenous compound with an alkali1 and in the other ammonium sulfate is produced by moist combustion with sulfuric acid1 and the salt thus formed is subsequently distilled with an alkali1 and the free ammonia thus formed estimated as above described4 ,nitric nitrogen may also be reduced to ammonia by nascent hydrogen either in an acid or alkaline solution as described in volume first4 ,in the third class of determinations is included the estimation of nitric nitrogen by colorimetric methods as described in the first volume4 ,these processes have little practical value in connection with the analyses of commercial fertilizers1 but find their chief use in the detection and estimation of extremely minute quantities of nitrites and nitrates4 ,in the following paragraphs will be given the standard methods for the determination of nitrogen in practical work with fertilizing materials and fertilizers4 #aed4 ,official ,methods4--,the methods adopted by the ,association of ,official ,agricultural ,chemists have been developed by more than ten years of co-operative work on the part of the leading agricultural chemists of the ,united ,states4 ,these methods should be strictly followed in all essential points by all analysts in cases where comparison with other data are concerned4 ,future experience will doubtless improve the processes both in respect of accuracy and simplicity1 but it must be granted that1 as at present practiced1 they give essentially accurate results4 #aee4 ,volumetric ,estimation by ,combustion with ,copper ,oxid4--,this classical method of analysis is based on the supposition that by the combustion of a substance containing nitrogen in copper oxid and conducting the products of the oxidation over red-hot copper oxid and metallic copper1 all of the nitrogen present in whatever form will be obtained in a free state and can subsequently be measured as a gas4 ,the air originally present in all parts of the apparatus must first be removed either by a mercury pump or by carbon dioxid or by both together1 the residual carbon dioxid being absorbed by a solution of caustic alkali4 ,great delicacy of manipulation is necessary to secure a perfect vacuum and as a rule a small quantity of gas may be measured other than nitrogen so that the results of the analyses are often a trifle too high4 ,the presence of another element associated with nitrogen1 or the possible allotropic existence of that element1 may also prove to be a disturbing factor in this long-practiced analytical process4 ,for instance1 if nitrogen be contaminated with another element1 e4 g41 argon1 of a greater density the commonly accepted weight of a liter of nitrogen is too great and tables of calculation based on that weight would give results too high4 ,first will be given the official method for this process1 followed by a few simple variations thereof1 as practiced in this laboratory4 #aef4 ,the ,official ,volumetric ,method4--,this process may be used for nitrogen in any form of combination4#acc ,the apparatus and reagents needed are as follows3 ,combustion tube of best hard ,bohemian glass1 about sixty-six centimeters long and #ab4g millimeters internal diameter4 ,azotometer of at least #ajj cubic centimeters capacity1 accurately calibrated4 ,sprengel mercury air-pump4 ,small paper scoop1 easily made from stiff writing paper4 ,coarse cupric oxid4--,to be ignited and cooled before using4 ,fine cupric oxid4--,prepared by pounding ordinary cupric oxid in a mortar4 ,metallic copper4--,granulated copper1 or fine copper gauze1 reduced and cooled in a current of hydrogen4 ,sodium bicarbonate4--,free from organic matter4 ,caustic potash solution4--,make a supersaturated solution of caustic potash in hot water4 ,when absorption of carbon dioxid1 during the combustion1 ceases to be prompt1 the solution must be discarded4 ,filling the tube4--,of ordinary commercial fertilizers take from one to two grams for analysis4 ,in the case of highly nitrogenized substances the amount to be taken must be regulated by the amount of nitrogen estimated to be present4 ,fill the tube as follows3 7#a7 ,about five centimeters of coarse cupric oxid3 7#b7 ,place on the small paper scoop enough of the fine cupric oxid to fill1 after having been mixed with the substance to be analyzed1 about ten centimeters of the tube2 pour on this the substance1 rinsing the watch-glass with a little of the fine oxid1 and mix thoroughly with a spatula2 pour into the tube1 rinsing the scoop with a little fine oxid3 7#c7 ,about thirty centimeters of coarse cupric oxid3 7#d7 ,about seven centimeters of metallic copper3 7#e7 ,about six centimeters of coarse cupric oxid 7anterior layer73 7#f7 ,a small plug of asbestos3 7#g7 ,from eight-tenths to one gram of sodium bicarbonate3 7#h7 ,a large1 loose plug of asbestos2 place the tube in the furnace1 leaving about two and five-tenths centimeters of it projecting2 connect with the pump by a rubber stopper smeared with glycerol1 taking care to make the connection perfectly tight4 ,operation4--,exhaust the air from the tube by means of the pump4 ,when a vacuum has been obtained allow the flow of mercury to continue2 light the gas under that part of the tube containing the metallic copper1 the anterior layer of cupric oxid 7see 7#e7 above71 and the sodium bicarbonate4 ,as soon as the vacuum is destroyed and the apparatus filled with carbon dioxid1 shut off the flow of mercury and at once introduce the delivery-tube of the pump into the receiving arm of the azotometer just below the surface of the mercury seal1 so that the escaping bubbles will pass into the air and not into the tube1 thus avoiding the useless saturation of the caustic potash solution4 ,set the pump in motion and when the flow of carbon dioxid has very nearly or completely ceased1 pass the delivery-tube down into the receiving arm1 so that the bubbles will escape into the azotometer4 ,light the gas under the thirty centimeter layer of oxid1 heat gently for a few moments to drive out any moisture that may be present1 and bring to a red heat4 ,heat gradually the mixture of substance and oxid1 lighting one jet at a time4 ,avoid a too rapid evolution of bubbles1 which should be allowed to escape at the rate of about one per second or a little faster4 ,when the jets under the mixture have all been turned on1 light the gas under the layer of oxid at the end of the tube4 ,when the evolution of gas has ceased1 turn out all the lights except those under the metallic copper and anterior layer of oxid1 and allow to cool for a few moments4 ,exhaust with the pump and remove the azotometer before the flow of mercury is stopped4 ,break the connection of the tube with the pump1 stop the flow of mercury1 and extinguish the lights4 ,allow the azotometer to stand for at least an hour1 or cool with a stream of water until a permanent volume and temperature have been reached4 ,adjust accurately the level of the potash solution in the bulb to that in the azotometer2 note the volume of gas1 temperature1 and height of barometer2 make calculation as usual1 or read results from tables4 #aef4 ,note on ,official ,volumetric ,method4--,the determination of nitrogen in its gaseous state by combustion with copper oxid1 has practically gone out of use as an analytical method4 ,the official chemists rarely use it even for control work on samples sent out for comparative analysis4 ,the method recommended differs considerably from the process of ,jenkins and ,johnson1 on which it is based4 ,the only source of oxygen in the official method is in the copper oxid4 ,hence it is necessary that the oxid in immediate contact with the organic matter be in a sufficiently fine state of subdivision1 and that the substance itself be very finely powdered and intimately mixed with the oxidizing material4 ,failure to attend to these precautions will be followed by an incomplete combustion and a consequent deficit in the volume of nitrogen obtained4 ,the copper oxid before using is ignited1 and is best filled into the tube while still warm by means of a long pointed metal scoop1 or other convenient method4 ,the copper spiral1 after use1 is reduced at a red heat in a current of hydrogen1 and may thus be used many times4 #aeg4 ,the ,pump4--,any form of mercury pump which will secure a complete vacuum may be used4 ,a most excellent one can be arranged in any laboratory at a very small expense4 ,the pump used in this laboratory for many years answers every purpose1 and costs practically nothing1 being made out of old material not very valuable for other use4 ,the construction of the pump and its use in connection with the combustion tube will be clearly understood from the following description3 ,illustration3 ,,figure #aj4 ,,mercury ,,pump ,,and ,,azotometer4 ,a glass bulb ,i is attached1 by means of a heavy rubber tube carrying a screw clamp1 to the glass tube ,a1 having heavy walls and a small internal diameter1 and being one meter or more in length4 ,the tube ,a is continued in the form of a ,u1 the two arms being joined by very heavy rubber tubing securely wired4 ,the ends of the glass tubes in the rubber should be bent so that they come near together and form the bend of the ,u1 the rubber simply holding them in place4 ,this is better then to have the tube continuous1 avoiding danger of breaking4 ,a tee tube1 ,t1 made of the same kind of glass as ,a1 is connected by one arm1 a1 with the manometer ,b1 by a heavy rubber union well wired4 ,the union is made perfectly air-tight by the tube filled with mercury held by a rubber stopper4 ,the middle arm of the tee1 a1 is expanded into a bulb1 ,e1 branching into two arms1 one of which is connected with ,a and the other with the delivery-tube ,f1 by the mercury-rubber unions1 ,,mm1 just described4 ,the interior of the bulb ,e should be of such a shape as to allow each drop of mercury to fall at once into ,f without accumulating in large quantity and being discharged in mass4 ,the third arm of the tee a is bent upwards at the end and passes into a mercury sealing tube1 ,d1 where it is connected by means of a rubber tube with the delivery-tube from the furnace4 ,the flow of the mercury is regulated by the clamp ,c1 and care should be taken that the supply does not get so low in ,i as to permit air bubbles to enter ,a4 ,the manometer ,b dips into the tube of mercury ,h4 ,a pump thus constructed is simple1 flexible1 and perfectly tight4 ,the only part which needs to be specially made is the tee and the one in use here was blown in our own laboratory4 ,the bent end of the delivery-tube ,f may also be united to the main tube by a rubber joint thus aiding in inserting it into the ,v-shaped nozzle of the azotometer4 ,the azotometer used is the one devised by ,schiff and modified by ,johnson and ,jenkins4#acd ,we prefer to get the ,v nozzles separately and join them to any good burette by a rubber tube4 ,the water-jacket is not necessary1 but the apparatus can be left exposed until it reaches room temperature4 ,any form of mercury pump capable of securing a vacuum may be used1 but the one just described is commended by simplicity1 economy1 effectiveness1 and long use4 #aeh4 ,the ,pump and ,combustion ,furnace4--,the pump and combustion furnace1 as used in the laboratory1 are shown in ,fig4 #aj4 ,the pump is constructed as just described1 and rests in a wooden tray which catches and holds any mercury which may be spilled4 ,the furnace is placed under a hood which carries off the products of the burning lamps and the hot air4 ,a well-ventilated hood is an important accessory to this process1 especially when it is carried on in summer4 ,a small mercury pneumatic trough catches the overflow from the pump and also serves to immerse the end of the delivery-tube during the exhaustion of the combustion tube4 ,the other details of the arrangement and connections have been sufficiently shown in the previous paragraph4 #aei4 ,volumetric ,method in this ,laboratory4--,it has been found convenient here to vary slightly the method of the official chemists in the following respects3 ,the tube used for the combustion is made of hard refractory glass1 which will keep its shape at a high red heat4 ,it is drawn out and sealed at one end after being well cleaned and dried4 ,it should be about eighty centimeters in length and from twelve to fourteen millimeters in internal diameter4 ,the relative lengths of the spaces occupied by the several contents of the tube are approximately as follows3 ,sodium bicarbonate1 two2 asbestos1 three2 coarse copper oxid1 eight2 fine copper oxid1 containing sample1 sixteen2 coarse copper oxid1 twenty-five2 spiral copper gauze1 ten to fifteen2 copper oxid1 eight2 and asbestos plug1 five centimeters1 respectively4 ,the copper oxid should be heated for a considerable time to redness in a muffle with free access of air before using and the copper gauze be reduced to pure metallic copper in a current of hydrogen at a low red heat4 ,the anterior layer of copper oxid serves to oxidize any hydrogen that may have been occluded by the copper4 ,when a sample is burned containing all or a considerable part of the nitrogen as nitrates1 the longer piece of copper gauze is used4 #afj4 ,the ,combustion4--,the tube having been charged and connected with the pump it is first freed from air by running the pump until the mercury no longer rises in the manometer4 ,the end of the tube containing the sodium bicarbonate is then gently heated so that the evolution of carbon dioxid will be at such a rate as to slowly depress the mercury in the manometer1 but never fast enough to exceed the capacity of the pump to remove it4 ,the lamp is extinguished under the sodium carbonate and the carbon dioxid completely removed by means of the pump4 ,the delivery-tube is then connected with the azotometer1 and the combustion tube carefully heated from the front end backwards1 the copper gauze and coarse copper oxid being raised to a red heat before the part containing the sample is reached4 ,when the nitrogen begins to come off1 its flow should be so regulated by means of the lamps under the tube1 as to be regular and not too rapid4 ,from half an hour to an hour should be employed in completing the combustion4 ,since most samples of fertilizer contain organic matter1 the nitrogen will be mixed with aqueous vapor and carbon dioxid4 ,the former is condensed before reaching the azotometer1 and the latter is absorbed by the potassium hydroxid4 ,when the sample is wholly of a mineral nature it should be mixed with some pure sugar1 about half a gram1 before being placed in the tube4 ,when bubbles of gas no longer come over1 the heat should be carried back until there is a gradual evolution of carbon dioxid under the conditions above noted4 ,finally the gas is turned off and the pump kept in operation until the manometer again shows a perfect vacuum when the operation may be considered finished4 ,in the manipulation our chief variation from the official method consists in connecting the combustion apparatus with the measuring tube before the heat is applied to the front end of the combustion tube4 ,any particles of the sample which may have stuck to the sides of the tube on filling will thus be subject to combustion and the gases produced measured4 ,where it is certain that no such adhesion has taken place it is somewhat safer on account of the possible presence of occluded gases to heat the front end of the tube before connecting the combustion apparatus with the azotometer4 #afa4 ,method of ,johnson and ,jenkins4--,in the method of ,johnson and ,jenkins the principal variation from the process described consists in introducing into the combustion tube a source of oxygen whereby any difficultly combustible carbon may be easily oxidized and all the nitrogen be more certainly set free4#ace ,the potassium chlorate used for this purpose is placed in the posterior part of the tube1 which is bent at slight angle to receive it4 ,the sodium bicarbonate is placed in the anterior end of the tube4 ,the combustion goes on as already described1 and at its close the potassium chlorate is heated to evolve the oxygen4 ,the free oxygen is absorbed by the reduced copper oxid1 or consumed by the unburned carbon4 ,any excess of oxygen is recognized at once by its action on the copper spiral4 ,as soon as this shows signs of oxidation the evolution of the gas is stopped4 ,care must be taken not to allow the oxygen to come off so rapidly as to escape entire absorption by the contents of the combustion tube4 ,in such a case the nitrogen in the measuring tube would be contaminated4 ,it is rarely necessary in fertilizer analysis to have need of more oxygen than is contained in the copper oxid powder in contact with the sample during the progress of combustion4 #afb4 ,calculation of ,results4--,the nitrogen originally present in a definite weight of any substance having been obtained in a gaseous form its volume is read directly in the burette in which it is collected4 ,this instrument may be of many forms but the essential feature of its construction is that it should be accurately calibrated2 and the divisions so graduated as to permit of the reading of the volume accurately to a tenth of a cubic centimeter4 ,for this purpose it is best that the internal diameter of the measuring tube be rather small so that at least each ten cubic centimeters occupies a space ten centimeters long4 ,the volume occupied by any gas varies directly with the temperature and inversely with the pressure to which it is subjected4 ,the quantity of aqueous vapor which a moist gas may contain is also a factor to be considered4 ,inasmuch as the nitrogen in the above process of analysis is collected over a strong solution of potassium hydroxid capable of practically keeping the gas in a dry state the tension of the aqueous vapor may be neglected4 #afc4 ,reading the ,barometer4--,nearly all the barometers in use in this country have the scale divided in inches and the thermometers thereunto attached are graduated in ,fahrenheit degrees4 ,this is especially true of the barometers of the ,weather ,bureau which are the most reliable and most easy of access to analysts4 ,it is not necessary to correct the reading of the barometer for altitude1 but it is important to take account of the temperature at the time of observation4 ,there is not space here to give minute directions for using a barometer4 ,such directions have been prepared by the ,weather ,bureau and those desiring it can get copies of the circular4#acf ,the temperature of a barometer affects its accuracy in two ways4 ,first the metal scale expands and contracts with changing temperatures3 ,second1 the mercury expands and contracts also at a much greater rate than the scale4 ,if a barometer tube hold thirty cubic inches of mercury the contents will be one ounce lighter at #hj ,f4 than at #cb ,f4 ,the true pressure of the air is therefore not shown by the observed height of the mercurial column unless the temperature of the scale and of the mercurial column be considered4 ,tables of correction for temperature are computed by simple formulas based on the known coefficients of expansion of mercury and brass4 ,for barometers with brass scales the following formula is used for making the correction3 t - #bh4fc ,c -h --------------------- 4 #a4aact #ajigh ,in this formula t temperature in degrees ,fahrenheit and h observed reading of the barometer in inches4 ,example3--,temperature observed #gb4e ,barometer reading observed1 #bi4dae inches1 from which ,c #j4aafe1 and this number1 according to the conditions of the formula1 is to be subtracted from the observed reading4 ,the true reading in the case given is1 therefore1 #bi4bih inches or #gdd4b millimeters4 ,the observed reading #gdg4a 8 ----- ,and the correction #b4i 8 ,unless extremely accurate work be required the correction for temperature is of very little importance in nitrogen determinations in fertilizers4 ,each instrument sent out by the ,weather ,bureau is accompanied by a special card of corrections therefor1 but these are of small importance in fertilizer work4 ,in order then to get the correct weight of the gas from its volume the reading of the thermometer and barometer at the time of measurement must be carefully noted4 ,however1 after the end of the combustion1 the azotometer should be carried into another room which has not been affected by the combustion and allowed to stand until it has reached the room temperature4 ,every true gas changes its volume under varying temperatures at the same rate and this rate is the coefficient of gaseous expansion4 ,for one degree of temperature it amounts to #j4jjcffe of its volume4 ,representing the coefficient of expansion by ,k the volume of the gas as read by ,v1 the volume desired at any temperature by ,v1 the temperature at which the volume is read by t and the desired temperature by t1 the change in volume may be calculated by the following formula3 ,v ,v#a ,k7t - t74 ,example4--,let the volume of nitrogen obtained by combustion be thirty-five cubic centimeters1 and the temperature of observation #bb4 ,what would be the volume of the gas at #j8 ,making the proper substitutions in the formula the equation is reduced to the form below3 ,v #cea #j4jjcffe7j-bb7 or ,v #ce7a - #j4jhjfc7 #cb4ah4 ,thirty-five cubic centimeters of nitrogen therefore measured at #bb become #cb4ah cubic centimeters when measured at #j4 ,when gases are to be converted into weight after having been determined by volume1 their volume at #j must first be determined2 but this volume must also be calculated to some definite barometric pressure4 ,by common consent this pressure has been taken as that exerted by a column of mercury #gfj millimeters in height4 ,since the volume of a gas is inversely proportional to the pressure to which it is subjected1 the calculation is made according to that simple formula4 ,let the reading of the barometer1 at the time of taking the volume of gas1 be ,h1 and any other pressure desired ,h4 ,then we have the general formula3 ,,hv ,v 3 ,v ,h 3 ,h2 and ,v ----4 ,h ,example3 ,let the corrected reading of the barometer at the time of noting the volume of the gas be #gdj millimeters1 and the volume of the gas reduced to #j be #cb4ah cubic centimeters4 ,what will this volume be at a pressure of #gfj millimeters8 ,substituting the proper values in the formula1 we have3 7#cb4ah #gdj7 ,v ------------- #ca4cc #gfj ,therefore1 a volume of nitrogen which occupies a space of thirty-five cubic centimeters at a temperature of #bb1 and at a barometric pressure of #gdj millimeters1 becomes #ca4cc cubic centimeters at a temperature of #j and a pressure of #gfj millimeters4 ,one liter of nitrogen at #j and #gfj millimeters pressure weighs #a4bedef grams2 and one cubic centimeter therefore #j4jjabedef gram4 ,to find the weight of gas obtained in the above supposed analysis1 it will only be necessary to multiply this number by the volume of nitrogen expressed in cubic centimeters under the standard conditions2 viz41 #j4jabedef #ca4cc #j4jcicje gram4 ,if the sample taken for analysis weighed half a gram1 the percentage of nitrogen found would be #g4he4 #afd4 ,tension of the ,aqueous ,vapor4--,it has been shown by experience that when a gas is collected over a potash solution containing fifty per cent of potassium hydroxid1 the tension of the aqueous vapor is so far diminished as to be of no perceptible influence on the final result4 ,to correct the volume of a gas1 therefore1 so collected for this tension1 would involve an unnecessary calculation for practical purposes4 ,if a gas thus collected should be transferred to a burette over mercury1 on which some water floats1 then the correction should be made4 ,at #j the tension of aqueous vapor will support a column of mercury #d4ebe millimeters high1 and at #dj one of #ed4ifi millimeters4 ,the following table gives the tension of aqueous vapors in millimeters of a mercurial column for each degree of temperature from zero to forty4 ,tension of ,tension of vapor in vapor in ,temperature4 millimeters4 ,temperature4 millimeters4 #j #d4ebe #ba #ah4eje #a #d4hfg #bb #ai4fge #b #e4bca #bc #bj4iji #c #e4fai #bd #bb4baa #d #f4jcb #be #bc4ehb #e #f4dga #bf #be4jbf #f #f4ici #bg #bf4edg #g #g4dcf #bh #bh4adh #h #g4ifd #bi #bi4hcb #i #h4ebe #cj #ca4fjb #aj #i4abf #ca #cc4dfd #aa #i4gea #cb #ce4dai #ab #aj4dba #cc #cg4dgc #ac #aa4acj #cd #ci4fcj #ad #aa4hhb #ce #da4hic #ae #ab4fgg #cf #dd4bfh #af #ac4eai #cg #df4geh #ag #ad4dji #ch #di4cfh #ah #ae4cea #ci #eb4ajc #ai #af4cde #dj #ed4ifi #bj #ag4cif ,when a gas is in contact with water the aqueous vapor is diffused throughout the mass1 and the pressure to which the mixture is subjected1 is partly neutralized by the tension of the water vapor4 ,the real pressure to which the gas1 whose volume is to be determined is subjected1 is therefore diminished by that tension4 ,if for instance a gas in contact with water show a volume of thirty-five cubic centimeters at #bb and #gdj millimeters barometric pressure its volume is really greater than if it were perfectly dry4 ,how much greater can be determined by inspecting the table1 for at #bb the tension of water vapor is #ai4fge millimeters of mercury4 ,the real pressure to which the volume of gas is subjected is therefore #gdj - #ai4fge #gbj4cbe millimeters4 ,if1 therefore1 in the example given1 the nitrogen were in contact with water1 the calculation would proceed as follows3 #cb4ah #gbj4cbe ,v ----------------- #cj4e1 #gfj and #cj4e #a4bedef #ch4bf4 ,hence1 #ch4bf milligrams of nitrogen correspond to #g4fe per cent1 when half a gram of substance is taken for the combustion4 #afe4 ,aqueous ,tension in ,solutions of ,potassium ,hydroxid4--,even in strong solutions of potassium hydroxid the tension of aqueous vapor is not destroyed1 but is reduced to a minimum1 which is negligible in the calculation of the percentage by weight of the nitrogen in a sample of fertilizer4 ,when dilute solutions of a caustic alkali are used however1 the neglect of the tension of the aqueous vapor may cause an error of some magnitude4 ,in such cases the strength of the solution should be known and correction made according to the following table3#acg ,millimeters tension of aqueous vapor for ,,koh solutions of ---------------------------------------- ------------- ,temperature4 #i4ji per #af4ff per #bc4jh per #bh4eg per #cb4hi per cent4 cent4 cent4 cent4 cent4 #aj4jj #h4fb #h4ja #g4ca #f4ej #e4fb #aa4jj #i4ba #h4ef #g4hb #f4ie #f4ja #ab4aj #i4ij #i4ba #h4da #g4dg #f4df #ac4jj #aj4ej #i4gg #h4ib #g4ic #f4hf #ac4ie #aa4ag #aj4ci #i4di #h4dd #g4cj #ae4ae #ab4jf #aa4bb #aj4be #i4aa #g4hf #af4jj #ab4gd #aa4he #aj4hb #i4fb #h4cc #ag4jj #ac4eg #ab4fc #aa4ed #aj4bf #h4hh #ah4jj #ad4df #ac4de #ab4bi #aj4ic #i4dg #ai4jj #ae4ci #ad4cc #ac4ji #aa4fe #aj4ji #bj4jj #af4ch #ae4be #ac4ic #ab4dj #aj4ge #ba4jj #ag4db #af4bb #ad4hb #ac4bj #aa4dd #ba4hb #ah4cb #ag4jf #ae4ei #ac4hh #ab4jd #bc4jj #ai4fh #ah4cb #af4ge #ad4ib #ab4id #bd4jj #bj4ib #ai4dg #ag4hj #ae4hf #ac4gf #be4jj #bb4ai #bj4fg #ah4ia #af4he #ad4fb #bf4jj #bc4ee #ba4id #bj4jg #ag4hi #ae4ec #bf4ih #bd4ie #bc4be #ba4bg #ah4if #af4df #bg4ic #bf4ch #bd4ei #bb4ea #bj4jg #ag4de #bi4jj #bh4jh #bf4ah #bc4if #ba4ch #ah4ei #cj4jj #bi4gf #bg4gd #be4dj #bb4fg #ai4gb #ca4jj #ca4ea #bi4ch #bf4ia #bd4jc #bj4ia #cb4ac #cc4fa #ca4cd #bh4gb #be4fe #bb4cd #cc4jj #ce4cj #cb4ic #cj4ah #bf4ig #bc4ej #cd4jj #cg4cd #cd4hd #ca4id #bh4ef #bd4hi #aff4 ,use of ,volumetric ,method4--,for practical purposes it may be said that the volumetric determination of nitrogen in fertilizer analysis has gone entirely out of use4 ,for control and comparison it is still occasionally practiced but it has had to give way to the more speedy and fully as accurate processes of moist combustion with sulfuric acid which have come into general use in the last decade4 ,the student and analyst however should not fail to master its details and become skilled in its use4 ,there are certain nitrogenous substances such as the alkaloids which are quite refractory when subjected to moist combustion4 ,while such bodies may not occur in fertilizers it is well to have at hand a means of accurately determining their nitrogen content4 #afg4 ,tables for ,calculating ,results4--,where many analyses are to be made by the copper oxid process it has proved convenient to shorten the work of calculating analyses by taking the data given in computation tables4#ach ,before using these tables it must be known whether they are calculated on the supposition that the gas is measured in a moist state1 partly moist1 or wholly dry4 ,where the nitrogen is collected over water a table must be used in which allowance has been made for the tension of aqueous vapor4 ,in case a saturated solution of a caustic alkali be used in the azotometer it is customary to take no account of the tension and the table employed must be constructed on this supposition4 ,in point of fact even in the strongest alkali solution there is a certain amount of tension but this is so slight as only to affect the results in the second place of percentage decimals4 ,since1 as a rule1 only a few analyses are made by this method it will be found safer to use a caustic alkali solution of given strength and to calculate the results from the tables of aqueous tensions given above4 #afh4 ,the ,soda-,lime ,process4--,this process originally perfected by ,varrentrap and ,will1 and improved by ,peligot1 was used almost exclusively by analysts until within the last decade for the determination of nitrogen not existing in the nitric form4 ,it is based on the principle that when nitrogen exists as a salt of ammonia1 or as an amid1 or as proteid matter1 it is converted into gaseous ammonia by combustion with an alkali4 ,this ammonia can be carried into a set solution of acid by a stream of gas free of ammonia and the excess of acid remaining after the combustion is complete can be determined by titration against a standard alkali solution4 ,the results under proper conditions are accurate even when a small quantity of nitric nitrogen is present4 ,when1 however1 there is any considerable quantity of this compound in the sample the method becomes inapplicable by reason of non-reduction of some of the nitrogen oxids produced by the combustion4 ,in bodies very rich in nitrogen such as urea all the nitrogen is not transformed directly into ammonia at the commencement of the combustion4 ,a portion of it may unite with a part of the carbon to form cyanogen1 which may unite with the soda to form sodium cyanid4 ,with an excess of alkali1 however1 and prolonged combustion this product will be finally decomposed and all the nitrogen be secured as ammonia4 ,the nascent hydrogen which unites with the nascent nitrogen during the combustion is also derived from the organic matter which always contains enough carbon to decompose the water formed in order to be oxidized to carbon dioxid4 ,while at first1 therefore1 during combustion1 the hydrogen may unite with the oxygen1 it becomes again free by the oxidation of the carbon and in this condition unites with the nascent nitrogen to form ammonia4 ,in addition to carbon dioxid1 ammonia1 and free hydrogen there may also be found among the products of combustion marsh and olefiant gases and other hydrocarbon compounds which dilute1 to a greater or less extent1 the ammonia formed and help to carry it out of the combustion tube and into the standard acid4 #afi4 ,the ,official ,method4--,reagents and ,apparatus4--7#a7 ,standard solutions and indicator the same as for the kjeldahl method3 7#b7 ,dry granulated soda-lime1 fine enough to pass a #b4e millimeter sieve3 7#c7 ,soda-lime1 fine enough to pass a #a4be millimeter sieve4#aci ,soda-lime may be easily and cheaply prepared by slaking two and one-half parts of quicklime with a strong solution of one part of commercial caustic soda1 care being taken that there is enough water in the solution to slake the lime4 ,the mixture is then dried and heated in an iron pot to incipient fusion1 and1 when cold1 ground and sifted as above4 ,instead of soda-lime ,johnson's mixture of sodium and calcium carbonate1 or slaked lime may be used4 ,slaked lime may be granulated by mixing it with a little water to form a thick mass1 which is dried in the water-oven until hard and brittle4 ,it is then ground and sifted as above4 ,slaked lime is much easier to work with than soda-lime1 and gives excellent results1 though it is probable that more of it should be used in proportion to the substance to be analyzed than is the case with soda-lime4 7#d7 ,asbestos1 which has been ignited and kept in a glass-stoppered bottle4 7#e7 ,combustion tubes about forty centimeters long and twelve millimeters internal diameter1 drawn out to a closed point at one end4 7#f7 ,large-bulbed ,u tubes with glass stop-cock1 or ,will's tubes with four bulbs4 ,manipulation4--,the substance to be analyzed should be powdered finely enough to pass through a sieve of one millimeter mesh2 from seven-tenths to one and four-tenths grams1 according to the amount of nitrogen present1 are taken for the determination4 ,into the closed end of the combustion tube1 put a small loose plug of asbestos1 and upon it about four centimeters of fine soda-lime4 ,in a porcelain dish or mortar1 mix the substance to be analyzed1 thoroughly but quickly1 with enough fine soda-lime to fill about sixteen centimeters of the tube1 or about forty times as much soda-lime as substance1 and put the mixture into the combustion tube as quickly as possible by means of a wide-necked funnel1 rinsing out the dish and funnel with a little more fine soda-lime1 which is to be put in on top of the mixture4 ,fill the rest of the tube to within about five centimeters of the end with granulated soda-lime1 making it as compact as possible by tapping the tube gently while held in a nearly upright position during the filling4 ,the layer of granulated soda-lime should not be less than twelve centimeters long4 ,lastly1 put in a plug of asbestos about two centimeters long1 pressed rather tightly1 and wipe out the end of the tube to free it from adhering soda-lime4 ,connect the tube by means of a well-fitting rubber stopper or cork with the ,u tube or ,will's bulbs1 containing ten cubic centimeters of standard acid1 and adjust it in the combustion furnace so that the end of the tube projects about four centimeters from the furnace1 supporting the ,u tube or ,will's bulb suitably4 ,heat the portion of the tube containing the granulated soda-lime to a moderate redness1 and when this is attained extend the heat gradually through the portion containing the substance1 so as to keep up a moderate and regular flow of gases through the bulbs1 maintaining the heat of the first part until the whole tube is heated uniformly to the same degree4 ,continue the combustion until gases have ceased bubbling through the acid in the bulbs1 and the mixture of substance and soda-lime has become white1 or nearly so1 which shows that the combustion is finished4 ,the process should occupy about three-quarters of an hour1 or not more than one hour4 ,remove the heat1 and when the tube has cooled below redness break off the closed tip and aspirate air slowly through the apparatus for two or three minutes to bring all the ammonia into the acid4 ,disconnect the tube1 wash the acid into a beaker or flask1 and titrate with the standard alkali4 ,during the combustion the end of the tube projecting from the furnace must be kept heated sufficiently to prevent the condensation of moisture1 yet not enough to char the stopper4 ,the heat may be regulated by a shield of tin slipped over the projecting end of the combustion tube4 ,it is found very advantageous to attach a bunsen valve to the exit tube1 allowing the evolved gases to pass out freely1 but preventing a violent sucking back in case of a sudden condensation of steam in the bulbs4 #agj4 ,the ,official ,french ,method4--,the ,french chemists prefer to drive out the traces of ammonia remaining in the combustion tube by means of the gases arising from the decomposition of oxalic acid4#adj ,the operation is conducted by mixing about one gram of oxalic acid with enough of dry granular soda-lime to form a layer of four centimeters in length at the bottom of the tube4 ,the rest of the tube is then charged substantially as directed above4 ,at the end of the combustion the oxalic acid is decomposed by heat furnishing sufficient hydrogen to remove from the tube all traces of ammonia which it may contain4 ,the ,french chemists employ1 for titration1 either normal acids and alkalies or some decimal thereof or else an acid of such strength as to have each cubic centimeter thereof correspond to ten milligrams of nitrogen1 thus making the computation of results exceedingly simple4 ,such an acid is secured when one liter thereof contains thirty-five grams of pure monohydric sulfuric acid or forty-five grams of pure crystallized oxalic acid4 ,the corresponding alkaline reagent should contain1 in each liter1 forty grams of pure potassium hydroxid4 #aga4 ,the ,hydrogen ,method4--,thibault and ,wagner recommend that the combustion with soda-lime be conducted in an atmosphere of hydrogen1#ada and ,loges replaces this by common illuminating gas freed from ammonia by conducting it through a tube filled with glass balls moistened with dilute sulfuric acid4#adb ,in these cases the combustion tube is left open at both ends and the materials under the tube confined to the proper position by asbestos plugs4 ,the gases used act in a merely mechanical manner and their use affords so few advantages over the method of aspirating air at the end of the combustion as to render it unadvisable4 #agb4 ,coloration of the ,product4--,it often happens1 especially in the combustion of animal products1 such as tankage and fish scrap1 that the acid securing the ammonia is deeply colored by the condensation of some of the other products of combustion4 ,this coloration interferes in a very serious way with the delicacy of the indicator used to determine the end of the reaction4 ,in this case the liquid may be mixed with an alkali and distilled and the ammonia secured in a fresh portion of the standard acid as in the moist combustion process to be hereafter described4 #agc4 ,general ,considerations4--7#a7 ,preparation of ,sample4--,in the soda-lime method it is of great importance that the organic substances be in a fine state of subdivision so as to admit of intimate mixture with the alkali4 ,in cases where fragments of hoof1 horn1 hair1 or similar substances are to be prepared for combustion it is advisable to first decompose them by heating with a small quantity of sulfuric acid4 ,the excess of acid may be neutralized with marble dust and the resulting mixture dried1 rubbed to a fine powder1 and mixed with the soda-lime in the usual way4 ,care must be taken not to lose any of the ammonia from the sulfate which may be formed in mixing with the soda-lime in filling the tube4 7#b7 ,purity of ,soda-,lime4--,the soda-lime employed must be entirely free of nitrogenous compounds and some blank combustions should be made in proof of its purity4 7#c7 ,temperature4--,the temperature of the combustion should not be allowed to exceed low redness4 ,at very high temperatures there would be danger of decomposing the ammonia4 7#d7 ,aspiration of ,air4--,before aspiring a current of air through the tube to remove the last traces of ammonia the gas should be put out under the furnace and the tube be allowed to cool below redness to avoid any danger of acting on the nitrogen in the air4 #agd4 ,the ,ruffle ,soda-,lime ,method4--,many attempts have been made to adapt the soda-lime method to the determination of nitric nitrogen4 ,of these the process devised by ,ruffle is the only one which has proved successful4#adc ,the method is founded on the action of sulfurous vapors on the nitrogen oxids produced during the combustion whereby sulfuric acid is formed and the nascent nitrogen is joined with hydrogen to form ammonia4 ,by this process all the nitrogen contained in the sample1 even if in the nitric form1 is finally obtained as ammonia4 ,in the original method the reagents employed were a mixture of sodium thiosulfate and soda-lime and a mixture of charcoal1 sulfur1 and granulated soda-lime4 ,subsequently the official chemists substituted sugar for the charcoal4#add ,the method was used for a long time by the official chemists and came into general favor until displaced by the simpler and cheaper processes of the moist combustion method adapted to nitric nitrogen4 ,as finally modified and used by the official chemists the process was conducted as described below4 #age4 ,the ,official ,ruffle ,method4--#ade,reagents4--7#a7 ,standard solutions and indicator the same as for the kjeldahl method4 7#b7 ,a mixture of equal parts by weight of fine-slaked lime and finely powdered sodium thiosulfate dried at #ajj3 7#c7 ,a mixture of equal parts of weight of finely powdered granulated sugar and flowers of sulfur3 7#d7 ,granulated soda-lime1 as described under the soda-lime method3 7#e7 ,combustion tubes of hard ,bohemian glass seventy centimeters long and one and three-tenths centimeters in diameter3 7#f7 ,bulbed ,u tubes or ,will's bulbs1 as described under the soda-lime method3 ,manipulation4--7a7 ,clean the ,u tube and introduce ten cubic centimeters of standard acid4 7b7 ,fit the cork and glass connecting tube4 ,fill the tube as follows3 7#a7 ,a loosely fitting plug of asbestos1 previously ignited1 and then two and five-tenths to three and five-tenths centimeters of the thiosulfate mixture3 7#b7 ,the weighed portion of the substance to be analyzed is intimately mixed with from five to ten grams of the sugar and sulfur mixture3 7#c7 ,pour on a piece of glazed paper or in a porcelain mortar a sufficient quantity of thiosulfate mixture to fill about twenty-five centimeters of the tube2 then add the substance to be analyzed1 as previously prepared1 mix carefully1 and pour into the tube2 shake down the contents of the tube2 rinse off the paper or mortar with a small quantity of the thiosulfate mixture and pour into the tube2 then fill up with soda-lime to within five centimeters of the end of the tube3 7#d7 ,place another plug of ignited asbestos at the end of the tube and close with a cork3 7#e7 ,hold the tube in a horizontal position and tap on the table until there is a gas-channel along the top of the tube3 7#f7 ,make connection with the ,u tube containing the acid2 aspirate and see that the apparatus is tight4 ,the ,combustion4--,place the prepared combustion tube in the furnace1 letting the open end project a little1 so as not to burn the cork4 ,commence by heating the soda-lime portion until it is brought to a full red heat4 ,then turn on slowly jet after jet toward the outer end of the tube1 so that the bubbles come off two or three a second4 ,when the whole tube is red hot and the evolution of the gas has ceased and the liquid in the ,u tube begins to recede toward the furnace1 attach the aspirator to the other limb of the ,u tube1 break off the end of the tube1 and draw a current of air through for a few minutes4 ,detach the ,u tube and wash the contents into a beaker or porcelain dish2 add a few drops of the cochineal solution1 and titrate4 #agf4 ,observations4--,in our experience we have found it much more satisfactory to adhere to the earlier directions for preparing the mixture of thiosulfate and alkali4 ,we much prefer to make the mixture with soda-lime and without the previous drying of the sodium salt4 ,ruffle himself says that the sodium thiosulfate should be dry but not deprived of its water of crystallization4#adf ,the best method to dry the crystal powder without depriving it of its crystal water is to press it between blotting papers4 ,the official method also contains a typographical error in prescribing that the combustion tube should have a length of thirty centimeters where evidently thirty inches were meant4 ,ruffle's original tube was twenty-two inches in length4 ,as is seen from the above description the method is essentially a reduction process by the action of a powerful deoxidizer in the presence of an alkali4 ,the crystals of the thiosulfate salt cannot be brought into direct contact with a pure alkali1 like soda or potash1 without forming at once a wet mass which would tend to cake and obstruct the tube4 ,the soda-lime is therefore a mechanical device to prevent this fusion4 ,where many analyses are to be made an iron tube1 for economical reasons1 may be substituted for the glass2 but the glass tube permits a more intelligent observation of the progress of the analysis4 ,since charcoal has very high absorbent powers it will be found always to contain a little nitrogen which may be in a form to generate ammonia during the combustion4 ,the charcoal used should therefore be previously boiled with caustic soda or potash solution1 dried1 powdered1 and preserved in well-stoppered bottles4 ,although pure sugar is practically free of nitrogen1 even when it is used1 it is advisable to occasionally make a blank determination and thus ascertain the correction to be made for possible contamination4 #agg4 ,boyer's ,modification of ,ruffle's ,method4--,the principle of the method rests on the observation that if nitrates be heated in a combustion tube with calcium oxalate and soda-lime1 not more than two-thirds of the total nitrogen appear as ammonia2 but if a certain proportion of sulfur be added the whole of the nitrogen is recovered4#bc ,the process may be divided into two reactions2 viz43 7#a7 ,action of the calcium oxalate upon the sodium nitrate in presence of soda-lime3 7#b7 ,the action of sulfurous acid and of calcium oxalate upon the sodium nitrate in presence of soda-lime4 ,the analysis is conducted as follows3 ,dry and pulverize one-half gram of nitrate 7,na or ,k7 and mix it intimately with fifty grams of the reducing compound containing approximately ten per cent sulfur1 #bb4e per cent neutral calcium oxalate1 and #fg4e per cent soda-lime4 ,the combustion tube is charged as follows3 ,length of tube fifty-five centimeters3 ,diameter of tube seventeen millimeters3 ,add first two grams pulverized calcium oxalate3 ,add next ten grams pulverized soda-lime3 8 8 ten grams of the reducing compound3 8 8 the nitrate incorporated with fifty grams of the reducing mixture3 ,add next ten grams of the reducing mixture3 8 8 ten grams pulverized soda-lime3 ,the tube is then lightly closed with an asbestos plug4 ,the tube is heated gradually from the front backwards1 the calcium oxalate furnishing finally the gas necessary to drive out the last traces of ammonia4 ,the process is equally applicable to the determination of nitrogen in all its forms or to mixtures thereof4 ,the method has also been applied to the mixture of ammoniacal and organic nitrogen and to the mixture of ammoniacal1 nitric1 and organic nitrogen1 the combustions having been made both in an iron and a glass tube4 ,the amounts of material to be used vary from one-half gram to a gram1 according to its richness in nitrogen4 ,the combustion should be terminated in forty minutes4 ,when a combustion is terminated1 the acid containing the ammonia is placed in a beaker and boiled for two or three minutes to drive off the sulfurous and carbonic acids4 ,the titration is then conducted in the usual manner4 ,the combustion can be carried on just as well in an iron tube as in a glass one4 ,the reagents employed1 especially soda-lime1 being hygroscopic1 a little water is disengaged in heating1 which is condensed at the cold extremity of the tube1 and which may absorb a little ammonia1 unless special precautions are taken to have the materials dry4 ,,the ,,moist ,,combustion ,,process4 #agh4 ,historical4--,as long ago as #ahfh ,wanklyn proposed to conduct the combustion of organic bodies in a wet way1 using potassium permanganate as the oxidizing body4#adg ,about ten years after this he attempted to extend the method so as to estimate the quantity of proteid matter in a sample by treatment with an alkaline solution in presence of the permanganate salt4 ,one gram of the finely pulverized sample was treated in a liter flask with one-tenth normal potash lye4 ,after digestion for some time1 from ten to twenty cubic centimeters were taken for the determination4 ,according to the supposition of ,wanklyn1 pure albuminoid matters thus treated yielded one-tenth of their weight of ammonia1 or about fifty per cent of the total nitrogen appeared as ammonia4 ,the ammonia content of the sample was determined by the colorimetric process devised by ,nessler4 ,it is needless to add that the process of ,wanklyn proved to be of no practical use whatever1 acting differently on different albuminoid matters1 and even on the same substance4 ,no other attempt was made to perfect the moist combustion process until ,kjeldahl#adh introduced the sulfuric acid method in #ahhc4 ,the simplicity1 economy1 and adaptability of this method have brought it into general use4 ,at first the process was only applied to organic nitrogenous compounds in the absence of nitrates1 but especially by the modifications proposed by ,asboth1 ,jodlbaur1 and ,scovell1 it has been made applicable to all cases1 with the possible exception of a few alkaloidal and allied bodies4 ,the moist combustion process for determining nitrogen is now generally employed by chemists in all countries1 not only for fertilizer control1 but also for general work4 #agi4 ,the ,method of ,kjeldahl4--,the process originally proposed by ,kjeldahl is applicable only to nitrogenous bodies free of nitric nitrogen4 ,the principle of the process is based on the action of concentrated sulfuric acid at the boiling-point in decomposing nitrogenous compounds without producing volatile combinations and the subsequent completion of the oxidation by means of potassium permanganate4 ,the original process has been modified by many analysts but the basic principle of it has remained unchanged4 ,it will therefore prove useful here to describe the process as originally given4#adi ,the weighed substance is placed in a small flask4 ,with solid bodies this is a very simple operation1 but with liquids more difficult4 ,liquids which are not decomposed1 on heating1 should be evaporated in a thin glass dish which can be ground up and placed in the digestion flask with the desiccated sample4 ,the strongest sulfuric acid is added in sufficient quantity to secure complete decomposition1 not less than ten cubic centimeters in any case4 ,the acid must be free of ammonia and be kept in such a way as not to absorb ammonia from the atmosphere of the laboratory4 ,to guard against danger of error from such an impurity frequent control determinations should be made4 ,in control experiments one or two grams of pure sugar should be used as the organic matter4 ,if the acid employed contain traces of ammonia the necessary corrections should be made in each analysis4 ,the flask having been charged is placed on a wire gauze over a small flame4 ,the organic matter becomes black and tar-like and soon there is a rapid decomposition attended with the evolution of gaseous products among which sulfur dioxid is found4 ,to avoid danger from spurting1 the digestion flask should be placed in an oblique position4 ,the flask should have1 at least1 a capacity of #ajj cubic centimeters and a long neck and be made of a kind of glass capable of withstanding the action of the boiling acid4 ,particles of the carbonized organic matter left on the sides of the flask by the foaming of the mass at first are gradually dissolved by the vapors of the boiling acid as the digestion proceeds4 ,the action of the sulfuric acid is not entirely finished when gases cease to be given off but the digestion should be continued until the liquid in the flask is clear and colorless or nearly so4 ,usually about two hours are required to secure this result4 ,when aided by the means mentioned below the time of digestion can be very materially shortened4 ,by adding some fuming sulfuric acid1 or glacial phosphoric acid1 the dilution caused by the formation of water in the combustion of the organic matter1 can be avoided4 ,for albuminoid bodies it is hardly necessary to continue the combustion until all carbonaceous matter is destroyed4 ,the full complement of ammonia is usually obtained after an hour's combustion even if the liquid be still black or brown1 but with other nitrogenous bodies the case is different so that upon the whole it is safest to secure complete decoloration4 ,the temperature must be maintained at the boiling-point of the acid or near thereto since at a lower temperature1 for instance from #ajj to #aej1 the formation of ammonia is incomplete4 ,since all organic substances of whatever kind are dissolved by the boiling acid the previous pulverization of the material need be carried only far enough to secure a fair sample4 ,many substances give up practically all their nitrogen as ammonium sulfate when heated with sulfuric acid as1 for instance1 urea1 asparagin1 and the glutens4 ,in most of the other organic bodies fully ninety per cent of the nitrogen are likewise secured as the ammonium salt4 ,in the aromatic compounds1 or even in the form of amid in anilin salts1 the nitrogen is more resistant to the action of sulfuric acid4 ,in the alkaloids where the nitrogen is probably a real component of the benzol skeleton the formation of ammonia is very incomplete4 ,but even in the cases where the conversion of the nitrogen into ammonia is practically perfect it is advisable to finish the process by completing the oxidation with potassium permanganate4 ,the permanganate should be used in a dry powdered form and added little by little to the hot contents of the digestion flask1 the latter being held in an upright position and removed meanwhile from the lamp4 ,when carefully performed there is no danger of loss of ammonia although the oxidation is1 at times1 so vigorous as to be attended with evolution of light4 ,the permanganate must always be added in excess and until a permanent green color is produced4 ,the flask is then gently heated for from five to ten minutes over a small flame1 but this is not important4 ,the heating must not be too strong or else a strong evolution of oxygen will take place with a consequent reduction of the manganese compound4 ,when this happens the liquid again becomes clear and there is a loss of ammonia4 ,after cooling1 the contents of the flask are diluted with water1 the green color giving place to a brown with a rise of temperature4 ,after cooling a second time the whole is brought into a distillation flask of about three-quarters of a liter capacity and attached to a condenser which ends in a vessel containing titrated sulfuric acid4 ,about forty cubic centimeters of sodium hydroxid solution of one and three-tenths specific gravity are added and the stopper at once inserted to prevent any loss of ammonia4 ,to prevent bumping during the distillation some zinc dust is added securing an evolution of hydrogen during the progress of the distillation4 ,in this case the bumping is prevented until near the end of the operation when it begins anew1 probably by reason of the separation of solid sodium sulfate4 ,after the end of the distillation1 the excess of acid remaining in the receiver is determined by a set alkali solution and thus the quantity of ammonia obtained easily calculated4 ,kjeldahl1 however1 preferred to titrate the solution after adding potassium iodate and iodid1 a mixture which in the presence of a strong acid sets free a quantity of iodin equivalent to the free acid present4 ,the iodin thus set free is titrated by a set solution of sodium thiosulfate using starch as an indicator4 ,the merits of this method are sharpness of the end reaction and the possibility of using only a small quantity of the nitrogenous body for the combustion4 ,the sulfuric acid used in the receiver is made of the same strength as the thiosulfate solution2 viz41 about one-twentieth normal4 ,thirty cubic centimeters of this were found to be the proper amount for use with substances taken in such quantities as to produce ammonia enough to neutralize about half of it4 ,the titration is carried on as follows3 ,a few crystals of potassium iodid are dissolved in the acid mixture obtained after the distillation is completed1 then a few drops of the starch-paste and finally a few drops of a four per cent solution of potassium iodate4 ,the iodin set free is then oxidized by the addition of the one-twentieth normal sodium thiosulfate solution until the blue color disappears4 ,example3 ,sulfuric acid used1 #cj cc4 ,equivalent to sodium thiosulfate1 #cj cc4 ,blank combustion required1 #bi4h cc thiosulfate solution4 ,combustion of #j4fde gram of barley #ad4e cc 8 8 required1 ------- ,thiosulfate corresponding to barley1 #ae4c cc4 ,in the computation it is more simple to multiply the corresponding number of cubic centimeters of thiosulfate by seven1 half the atomic weight of nitrogen1 and divide the product by the weight of the substance taken1 which will give the per cent of nitrogen therein4 #ae4c #g ,then ---------- #ajj #a4ff per cent of nitrogen in sample taken4 #j4fde ,a more detailed description of the method of making the titration follows3 ,after the distillation is finished the condensing-tube is rinsed with a little water1 after which the sulfuric acid unneutralized in the receiver is determined4 ,it is advisable first to test the reaction of the distillate with litmus paper before going any further2 for if at any time all the acid should be found neutralized it will be necessary to add a sufficient quantity of one-twentieth normal sulfuric acid before adding the potassium iodid1 etc41 otherwise the determination will be irreparably lost4 ,add to the contents of the flask ten cubic centimeters of the potassium iodid and two cubic centimeters of the potassium iodate solutions1 described further on1 and the sodium thiosulfate is then run in from a burette till the fluid1 which is constantly kept agitated by shaking the flask1 shows only a bare trace of yellow coloration from the iodin still present4 ,starch solution is then added1 and the blue color obtained is at once removed by additional thiosulfate solution4 ,when some experience has been gained1 the eye is able to discern1 with great certainty1 even the slight coloration caused by only a small trace of free iodin4 ,in regard to the sensitiveness of the end reaction and the accuracy of the result1 this method of titration leaves nothing to be wished for4 ,the strength of the thiosulfate solution is determined in exactly the same manner1 and with starch as an indicator4 ,for this purpose1 measure ten cubic centimeters of one-twentieth normal sulfuric acid into an erlenmeyer1 add #abj cubic centimeters of ammonia-free water1 ten cubic centimeters of potassium iodid solution1 and two cubic centimeters of iodate solution2 add thiosulfate solution till the fluid shows only the above-mentioned light yellow tint1 then add starch1 and finally thiosulfate4 ,in this way the strength of the thiosulfate is ascertained1 which of course must be occasionally re-determined1 under exactly the same conditions as with the nitrogen determinations themselves1 and every possible error is thereby excluded4 ,that the solution once decolorized within a short time again assumes a deep blue color1 is a matter of no concern1 inasmuch as both solutions are added in such a manner that the end reaction lies exactly at the point when the starch iodid reaction distinctly disappears4 #ahj4 ,theory of the ,reactions4--,as has been seen above the final product of heating a nitrogenous organic compound with sulfuric acid and an oxidizing body is ammonium sulfate4 ,the various steps by which this is obtained have been traced by ,dafert3#aej 7#a7 ,the sulfuric acid abstracts from the organic matter the elements of water3 7#b7 ,the sulfur dioxid produced by the action of the residual carbon on sulfuric acid exercises a reducing effect on the nitrogenous bodies present3 7#c7 ,from the nitrogenous bodies produced by the above reduction ammonia is formed by the action of an oxidizing body3 7#d7 ,the ammonia formed is at once fixed by the acid as ammonium sulfate4 ,according to the theory of ,asboth the hydrogen which is formed during the action of sulfuric acid on organic matter1 when in a nascent state1 also aids greatly in the production of ammonia4 ,this idea is based on the fact that with those bodies which afford a deficit of hydrogen the formation of ammonia is imperfect4#aea #aha4 ,preparation of ,reagents4--7#a7 ,pure ,sulfuric ,acid4--,as is well known the so-called pure sulfuric acid in the market usually contains ammonia1 a fact which compelled ,kjeldahl to determine the quantity of nitrogen in the acid in every instance1 and to make correction for the same in the analysis4 ,an acid absolutely free from this impurity may1 however1 easily be prepared by the distillation of the commercial article in a small glass retort holding easily about #djj cubic centimeters4 ,to conduct this operation without danger it is only necessary to arrange the apparatus so that the heavy fluid is heated to boiling1 not from the bottom of the retort1 but from its sides1 and that the upper portion of the body and neck is kept sufficiently warm so that the sulfuric acid fumes are not allowed to condense and flow back into the retort4 ,both these ends are attained simply by surrounding the retort with a piece of sheet iron1 cylinder-shaped beneath1 and with an oval upper part1 having an opening of about one centimeter in diameter for the neck of the retort4 ,to conduct the distillation a burner is used with an arrangement for spreading the flame4 ,to avoid with certainty all bumping of the sulfuric acid and the resulting danger therefrom1 the lamp is so arranged that only the products of combustion go up between the retort and its iron hood1 without allowing the flame itself to come into contact with the glass vessel4 ,the retort should be filled about half full1 or with #bjj cubic centimeters of acid4 ,by this device1 without any danger whatever1 about one liter of sulfuric acid may be distilled in a day4 ,the retort will stand numerous distillations4 ,once begun1 the distillation takes care of itself2 it is necessary to discontinue it when only the bottom of the retort is covered with sulfuric acid1 and to fill fresh acid through a funnel when the retort has cooled off4 ,the first twenty cubic centimeters of the distillate going over are collected by themselves and rejected4 ,what comes over later is1 as shown by experience1 absolutely ammonia-free1 and can be used without any correction1 for the nitrogen determinations according to ,kjeldahl4 ,the acid is kept in a stoppered bottle in a place not reached by ammonia fumes4 ,the ten cubic centimeter pipette used for measuring the quantity of sulfuric acid required for each determination1 is fastened in the perforated rubber stopper with which the bottle is kept closed1 and is itself closed above by a small rubber tube with a plug of glass wool in it4 7#b7 ,potassium ,permanganate4--,crystals of this salt are crushed 7not pulverized7 with a pestle into small pieces of about one-half millimeter size1 which are kept in a long glass tube of about ten millimeters diameter1 closed with a stopper4 7#c7 ,ammonia-free ,water4--,common distilled water cannot be used in the determination of nitrogen according to ,kjeldahl1 since it contains ammonia4 ,it may be obtained free from the same by redistillation in a large glass retort with the addition of a few drops of sulfuric acid4 ,all vessels used in the determination are rinsed out beforehand with this water4 7#d7 ,ammonia-free ,soda-lye is most conveniently prepared by adding #bgj grams of common sodium hydroxid in sticks1 little by little1 to one liter of distilled water which is kept continually boiling1 by means of a small flame1 in a good-sized silver dish4 ,the dish is kept covered with a glass plate4 ,care has to be exercised not to add the alkali too rapidly1 nor in too large quantities at a time for in this case the fluid will boil too violently at every addition of the alkali4 ,after the operation is finished the lye is at once siphoned into a glass flask1 and when cold1 is poured into a glass-stoppered bottle4 7#e7 ,one-twentieth ,normal ,sulfuric ,acid is prepared from sulfuric acid and water both absolutely ammonia-free1 and is kept in a place where no fumes of ammonia can reach it1 in a well-stoppered glass bottle1 the stopper being smeared with vaseline4 7#f7 ,sodium ,thiosulfate ,solution4--,this should be of the same strength as the one-twentieth normal sulfuric acid4 ,it is prepared by dissolving the salt in ammonia-free water1 and is compared with the acid1 to which has been added potassium iodid and iodate1 using starch as an indicator1 in the manner described above4 ,the solution is kept in a well-stoppered bottle1 in the dark4 ,when the salt and water used are perfectly pure1 it will keep unchanged for a long time4 7#g7 ,potassium ,iodid4--,dissolve five grams of chemically pure potassium iodid in ammonia-free water and make the volume #ajj cubic centimeters4 ,ten cubic centimeters of this solution are used for each determination2 keep the solution in the dark and in a well-stoppered bottle4 7#h7 ,potassium ,iodate4--,dissolve four grams of chemically pure potassium iodate in ammonia-free water and make the volume #ajj cubic centimeters4 ,use two cubic centimeters of this solution for each determination4 7#i7 ,starch ,solution4--,digest pure starch for about a week with dilute hydrochloric acid1 wash perfectly free from chlorin by decantation1 and finally dry it between filter-paper4 ,the starch is then dissolved in water with the aid of heat4 ,such a solution will keep for an indefinite time1 if it be saturated with common salt4 ,ten grams of this starch are dissolved in #a1jjj cubic centimeters of ammonia-free water2 use one or two cubic centimeters for each determination4 #ahb4 ,kjeldahl ,method as ,practiced by the ,holland ,royal ,experiment ,station4--,necessary ,reagents3 #a4 ,phosphosulfuric acid1 made by mixing a liter of sulfuric acid of specific gravity #a4hd with #bjj grams of phosphoric anhydrid3 #b4 ,alkaline sodium sulfid solution1 made by dissolving #ejj grams of sodium hydroxid and six grams of sodium sulfid or eight and one-half grams of potassium sulfid1 in a liter of water3 #c4 ,mercury3 #d4 ,paraffin in small pieces3 #e4 ,dilute sulfuric acid and dilute potash solution1 both of known strength3 #f4 ,pieces of previously ignited pumice stone or of granulated zinc3 #g4 ,neutral solution of rosolic acid or litmus4 ,apparatus3 ,the apparatus necessary consists of oxidation flasks of about #bjj cubic centimeters capacity and distillation flasks of about #ejj cubic centimeters capacity1 both of bohemian glass4 ,copper may be used for the distillation flasks4#aeb ,the ,process3 ,a gram of the sample to be analyzed is placed in an oxidation flask together with twenty cubic centimeters of phosphosulfuric acid and a drop of mercury1 about #fjj milligrams1 and heated till the fluid becomes colorless4 ,after cooling1 dilute and wash the contents of the flask into a distillation flask4 ,the resulting volume should be about #cjj cubic centimeters4 ,add #ajj cubic centimeters of the alkaline sodium sulfid solution and some pieces of ignited pumice stone or granulated zinc4 ,distill the ammonia1 receiving the distillate in a flask containing a known volume of the standard sulfuric acid4 ,titrate with tenth-normal potash1 using litmus or rosolic acid as indicator4 #ahc4 ,the ,kjeldahl ,method as ,practiced at the ,halle ,station4--,the method at present in vogue in the ,german stations of conducting the moist combustion process is well illustrated by the method of procedure followed at ,halle4#bi ,from seven-tenths to one and five-tenths grams of the sample are taken for analysis according to its richness in nitrogen4 ,because of the fact that so small a quantity of the sample is taken it is of the highest importance that it be perfectly homogeneous throughout its entire mass4 ,otherwise1 grave errors may arise4 ,from the sample1 as sent to the laboratory1 the analyst should take a subsample and this should be rubbed to a fine powder and the part used for analysis carefully taken therefrom4 ,if the sample be moist it may be rubbed up with an equal weight of gypsum1 in which case a double quantity is taken for the determination4 ,substances like bone-meal1 which do not keep well mixed1 especially when occasionally shaken1 should be intimately mixed before each weighing4 ,the sample taken for analysis is placed in a glass flask of about #aej cubic centimeters capacity4 ,the flasks should be made of a special glass to withstand the tension of the combustion4 ,those made by ,kavalier at ,sazava1 in ,bohemia1 have proved to be the most lasting4 ,a globule of mercury weighing a little less than one gram is placed in the flask and also twenty cubic centimeters of pure sulfuric acid of #a4hde specific gravity4 ,the mercury is conveniently measured by an apparatus suggested by ,wrampelmayer4 ,it consists of an iron tube holding mercury1 and is conveniently filled1 from time to time1 from a supply vessel placed in a higher position and joined by means of a heavy glass tube and rubber tube connections4 ,the lower end of the iron tube is provided with a movable iron stopper having a pocket just large enough to hold a globule of mercury1 weighing a little less than a gram4 ,on turning the stopper the pocket is brought opposite a discharge orifice and the measured globule of mercury is discharged4 ,with substances which tend to produce a strong foaming a little paraffin is used4 ,the flasks after they are charged are placed on circular digesting ovens under a hood as shown in figure #aa4 ,illustration3 ,,figure #aa4 ,,moist ,,combustion ,,apparatus ,,of ,,the ,,halle ,,agricultural ,,laboratory4 ,at first the tripodal support of the flasks is so turned as to bring them between the lamps and in this way a too rapid reaction is at first avoided4 ,after half an hour the tripods are so turned as to bring each flask directly over the lamp1 the flame of which is allowed to impinge directly against the glass4 ,the flame is so regulated that after the evolution of the sulfur dioxid has nearly ceased the contents of the flask are brought into gentle ebullition4 ,the boiling is continued until the contents of the flask are colorless1 usually about two hours4 ,as a rule such substances as cottonseed-meal and dried blood will take a longer time for complete combustion than other fertilizing materials4 ,during the combustion the flasks are closed with an oblong loose-fitting unground glass stopper4 ,when the oxidation is finished the contents of the flasks are allowed to cool1 the stoppers are removed1 and enough water is added to fill the flasks about three-quarters full4 ,the flasks are gently shaken1 and the possibility of breaking1 from the heat developed1 must not be overlooked4 ,to avoid confusion the flasks are all numbered before beginning the work1 and the numbers noted by the analyst in connection with the samples4 ,the contents of each one are next poured into the distillation flask and the digestion vessels are washed with #ajj cubic centimeters of water in three portions1 and the wash-water added to the liquid4 ,sometimes in washing out the digestion flask yellow basic mercury compounds separate on its walls1 but this does not1 in any way1 influence the accuracy of the results4 ,the distillation flasks should have about #fjj cubic centimeters capacity4 ,to avoid the transfer the digestion may take place in the distillation flask in which case the latter must be made of special glass as indicated4 ,to the liquid thus transferred are added seventy-five cubic centimeters of soda-lye containing one and one-half times as much potassium sulfid as is necessary to combine with the mercuric sulfate present4 ,the lye is of such a strength that sixty cubic centimeters are sufficient to neutralize the acid present4 ,it has a specific gravity of #a4cge and contains thirty-three grams of potassium sulfid in a liter4 ,in order to avoid the bumping which may take place during the distillation1 some granulated zinc should be added4 ,the distillation flask is closed with a rubber stopper carrying a bulb-tube which ends above in a glass tube about three-quarters of a meter long1 bent at an acute angle1 and passing obliquely downward on a convenient support4 ,this tube is connected by a rubber1 with the end tube bent nearly at a right angle and dipping into the standardized acid in the erlenmeyer receiver4 ,the general arrangement of the distilling apparatus is shown in figure #ab4 ,since the contents of the vessel are warmed by mixing with the soda-lye1 the flame can be turned on at full head at once at the commencement of the operation4 ,in about a quarter of an hour the liquid in the receiver will be at the boiling-point1 and the boiling should be continued for five minutes more1 making twenty minutes in all for the completion of the distillation4 ,by this boiling the contents of the receiver are not charged with carbon dioxid1 as might happen if a condenser were used4 ,the receiver contains twenty cubic centimeters of a standardized sulfuric acid solution and about fifty cubic centimeters of water4 ,illustration3 ,,figure #ab4 ,,distillation ,,apparatus ,,of ,,halle ,,agricultural ,,laboratory4 ,the acid used should contain #ch4a grams of sulfuric acid of #a4hde specific gravity in a liter2 and it should be set by titration with chemically pure sodium carbonate4 ,for this purpose seven-tenths gram of sodium carbonate is heated in a platinum crucible for two hours over a small flame1 weighed1 and placed in an erlenmeyer together with twenty cubic centimeters of the sulfuric acid1 care being taken to avoid loss from the vigorous evolution of carbon dioxid4 ,after boiling for ten minutes all the carbon dioxid is removed from solution4 ,after cooling1 the excess of acid is determined by titration with a standardized barium hydroxid solution1 using rosolic acid as indicator4 ,the solution of barium hydroxid is made as follows3 ,digest1 with warm water1 #bfj grams of caustic baryta1 ,ba7,,oh71 until it is nearly all dissolved1 filter1 and make up to a volume of ten liters and keep in a flask free of carbon dioxid4 ,a solution of barium hydroxid is to be preferred to the corresponding sodium compound for titration4 ,if traces of carbonate be formed in the two liquids1 the sodium salt will remain in solution while the barium compound will settle at the bottom of the flask4 ,the ,indicator4--,the indicator used to determine the end of the reaction is made by dissolving one gram of rosolic acid in fifty cubic centimeters of alcohol4 ,from one to two drops are enough for each titration4 ,the color reaction is less definite as the quantity of ammonia in the liquid increases4 ,when the titration solutions have been prepared as above described it is found to require about ninety of the barium hydroxid to neutralize twenty cubic centimeters of the sulfuric acid4 ,by direct titration with sodium carbonate it is ascertained how many grams of nitrogen the twenty cubic centimeters of sulfuric acid represent4 ,example4--,suppose the weight of the dried sodium carbonate prepared as above directed is #j4fihi gram4 ,na,,co1 ,n ,then #j4fihi 3 #ec x 3 #ad ,whence x #j4ahdfae gram of nitrogen4 ,suppose further that twenty cubic centimeters of sulfuric acid solution require ninety-four cubic centimeters of barium hydroxid for complete saturation and after treatment with the above amount of sodium carbonate1 ten and a half cubic centimeters of the barium solution to neutralize the remaining acid4 ,then #id - #aj4e #hc4e ,and #j4ahdfae3 #hc4e x3 #id4 ,whence x #j4bjghcj gram of nitrogen corresponding to twenty cubic centimeters of the sulfuric acid used4 ,then #j4bjghc #id #j4jjbbaa gram of nitrogen corresponding to one cubic centimeter of the barium hydroxid solution4 ,if then in the analysis of a fertilizer it is found that #fj4e cubic centimeters are required to neutralize the excess of sulfuric acid after distillation the percentage of nitrogen in the sample is found as follows3 #fj4e #j4jjbbaa #j4accgg4 #j4bjghc - #j4accgg #j4jgdjf4 #j4jgdjf #ajj #g4djf per cent nitrogen in sample when one gram is taken for the combustion4 #ahd4 ,the ,official ,kjeldahl ,method4 ,not ,applicable in the ,presence of ,nitrates4#aec--,reagents4--7#a7 ,acids4--7a7 ,standard hydrochloric acid the absolute strength of which has been determined by precipitating with silver nitrate1 and weighing the silver chlorid as follows3 ,to any convenient quantity of the acid to be standardized1 add solution of silver nitrate in slight excess1 and two cubic centimeters of pure nitric acid1 of specific gravity #a4b4 ,heat to boiling-point1 and keep at this temperature for some minutes without allowing violent ebullition1 constantly stirring until the precipitate assumes the granular form4 ,allow to cool somewhat1 and then pass the fluid through the asbestos4 ,wash the precipitate by decantation1 with #bjj cubic centimeters of very hot water1 to which have been added eight cubic centimeters of nitric acid and two cubic centimeters of dilute solution of silver nitrate containing one gram of the salt in #ajj cubic centimeters of water4 ,the washing by decantation is performed by adding the hot mixture in small quantities at a time1 and beating up the precipitate well with a thin glass rod after each addition4 ,the pump is kept in action all the time1 but to keep out dust during the washing the cover is only removed from the crucible when the fluid is to be added4 ,put the vessels containing the precipitate aside1 return the washings once through the asbestos so as to obtain them quite clear1 remove them from the receiver1 and set aside to recover the excess of silver4 ,rinse the receiver and complete the washing of the precipitate with about #bjj cubic centimeters of cold water4 ,half of this is used to wash by decantation and the remainder to transfer the precipitate to the crucible with the aid of a trimmed feather4 ,finish washing in the crucible1 the lumps of silver chlorid being broken down with a glass rod4 ,remove the second filtrate from the receiver and pass about twenty cubic centimeters of ninety-eight per cent alcohol through the precipitate4 ,dry at from #adj to #aej4 ,exposure for half an hour is found more than sufficient1 at this temperature1 to dry the precipitate thoroughly4 7b7 ,standard sulfuric acid1 the absolute strength of which has been determined by precipitation with barium chlorid and weighing the resulting barium sulfate3 ,for ordinary work half normal acid is recommended1 i4 e41 containing #ah4bbhe grams of hydrochloric or #bd4eahe grams sulfuric acid to the liter2 for work in determining very small amounts of nitrogen1 one-tenth normal acid is recommended4 ,in titrating mineral acids against ammonia solutions1 use cochineal as indicator4 7c7 ,sulfuric acid1 specific gravity #a4hd1 free of nitrates and also of ammonium sulfate1 which is sometimes added in the process of manufacture to destroy nitrogen oxids3 7#b7 ,standard alkali1 the strength of which1 relative to the acid1 has been accurately determined4 ,one-tenth normal ammonia solution1 i4 e41 containing #a4gjea grams of ammonia to the liter1 is recommended for accurate work3 7#c7 ,metallic mercury or mercuric oxid1 prepared in the wet way3 ,that prepared from mercuric nitrate can not be safely used4 7#d7 ,potassium permanganate finely pulverized3 7#e7 ,granulated zinc1 pumice stone1 or one-half gram of zinc dust is to be added to the contents of the flasks in distillation1 when found necessary1 in order to prevent bumping3 7#f7 ,potassium sulfid4--,a solution of forty grams of commercial potassium sulfid in one liter of water3 7#g7 ,soda4--,a saturated solution of sodium hydroxid free of nitrates3 7#h7 ,indicator4--,solution of cochineal prepared as follows3 ,tincture of cochineal is prepared by digesting for a day or two1 at ordinary temperatures1 and frequently agitating1 three grams of pulverized cochineal in a mixture of fifty cubic centimeters of strong alcohol with #bjj cubic centimeters of distilled water4 ,the solution is decanted or filtered through ,swedish paper4 ,apparatus4--7#a7 ,kjeldahl digestion flasks of hard1 moderately thick1 well-annealed glass3 ,these flasks are about twenty-two centimeters long1 with a round1 pear-shaped bottom1 having a maximum diameter of six centimeters and tapering out gradually in a long neck1 which is two centimeters in diameter at the narrowest part1 and flared a little at the edge4 ,the total capacity is from #bbe to #bej cubic centimeters4 7#b7 ,distillation flasks of ordinary shape1 of #eej cubic centimeters capacity1 or preferably flasks of well-annealed glass1 of the same capacity1 of pear-shaped bottom1 for both digestion and distillation1 fitted with a rubber stopper and a bulb-tube above to prevent the possibility of sodium hydroxid being carried over mechanically during distillation3 ,the bulbs are about three centimeters in diameter1 the tubes being of the same diameter as the condenser and cut off obliquely at the lower end4 ,this is adjusted to the tube of the condenser by a rubber tube4 ,manipulation4--7#a7 ,the ,digestion4--,from seven-tenths to three and five-tenths grams of the substance to be analyzed1 according to its proportion of nitrogen1 are brought into a digestion flask with approximately seven-tenths gram of mercuric oxid or its equivalent in metallic mercury and twenty cubic centimeters of sulfuric acid4 ,the flask is placed in an inclined position1 and heated below the boiling-point of the acid for from five to fifteen minutes or until frothing has ceased4 ,if the mixture froth badly1 a small piece of paraffin may be added to prevent it4 ,the heat is then raised until the acid boils briskly4 ,no further attention is required until the contents of the flask have become a clear liquid1 which is colorless or at least has only a very pale straw color4 ,the flask is then removed from the frame1 held upright1 and while still hot1 potassium permanganate is dropped in carefully and in small quantities at a time until1 after shaking1 the liquid remains of a green or purple color4 7#b7 ,the distillation4--,after cooling1 the contents of the flask are transferred to the distilling flask with about #bjj cubic centimeters of water1 a few pieces of granulated zinc1 pumice stone1 or one-half gram of zinc dust when found necessary to keep the contents of the flask from bumping1 and twenty-five cubic centimeters of potassium sulfid solution are added1 shaking the flask to mix its contents4 ,next add fifty cubic centimeters of the soda solution1 or sufficient to make the reaction strongly alkaline1 pouring it down the sides of the flask so that it does not mix at once with the acid solution4 ,connect the flask with the condenser1 mix the contents by shaking1 and distil until all ammonia has passed over into the standard acid4 ,the first #aej cubic centimeters of the distillate will generally contain all the ammonia4 ,this operation usually requires from forty minutes to one hour and a half4 ,the distillate is then titrated with standard alkali4 ,the use of mercuric oxid in this operation greatly shortens the time necessary for digestion1 which is rarely over an hour and a half in case of substances most difficult to oxidize1 and is more commonly less than an hour4 ,in most cases the use of potassium permanganate is quite unnecessary1 but it is believed that in exceptional cases it is required for complete oxidation1 and in view of the uncertainty it is always used4 ,the potassium sulfid removes all the mercury from the solution1 and so prevents the formation of mercurammonium compounds which are not completely decomposed by soda solution4 ,the addition of zinc gives rise to an evolution of hydrogen and prevents violent bumping4 ,previous to use1 the reagents should be tested by a blank experiment with sugar1 which will partially reduce any nitrates that are present1 which might otherwise escape notice4 ,illustration3 ,,figure #ac4 ,,distilling ,,apparatus4 #ahe4 ,the ,distillation ,apparatus in ,use in the ,laboratory of the ,department of ,agriculture4--,in this laboratory the distilling apparatus is arranged as shown in ,figure #ac4 ,the flasks are the same as are used in the digestion4 ,they are connected to the block tin condensers by the bulb and rubber tubes1 shown hanging on the projecting ends of the block tin condensers on the right and left of the figure4 ,the condensers are contained in a trough through which cold water flows during the distillation4 ,the bulb above the flask carries an emergent tube which extends to near the center of the bulb and is bent laterally to avoid any danger of carrying over any alkali that may be projected into the bulb during boiling4 ,the boiling is continued usually for nearly an hour or until bumping begins4 ,the table on which the apparatus is placed is so arranged as to permit of easy access on all sides4 ,the standard acid is held in erlenmeyers placed on wooden blocks so that the end of the condenser which is a drawn-out glass tube1 dips beneath the surface of the acid4 #ahf4 ,patrick's ,distilling ,flask4--,to avoid the expense and annoyance attending the breaking of the distilling flasks ,patrick has proposed to make them of copper4#aed ,the size1 about half a liter1 made for the evolution of oxygen for experimental purposes1 may be used4 ,a little excess of potassium sulfid is used to make up for any of it which might be consumed by the copper4 ,about twenty-five cubic centimeters of this solution are recommended4 ,no zinc or pumice stone is required to prevent bumping and the distillation may be finished within thirty minutes1 thus securing a saving of time4 ,there will doubtless be a slight corrosion of the flasks by the sulfid employed but where the gunning oxidation process is practiced this danger would be avoided4 #ahg4 ,modifications of the ,kjeldahl ,process4--,it would be impracticable here to give even a summary of the many unimportant changes which the moist combustion process has undergone since the first papers of its author were published4 ,these changes may be divided into three classes2 viz41 #a4 ,those changes which refer solely to the quantities of substance taken for analysis1 to the composition of the acid mixture1 to the duration of the digestion1 to the form and size of the flasks1 both for digestion and distillation1 and to the manner of distillation and of titration4 ,for references to the papers on these subjects the reader may consult the periodic journals4#aee ,the most important of these minor changes are the following3 ,instead of the titration by means of separated iodin most chemists have had recourse to the simpler method of direct titration of the excess of acid by a set solution of an alkali4 ,barium1 sodium1 and potassium hydroxids are the alkaline solutions most employed4 ,this process permits of a larger quantity of the sample being taken for combustion and of the use of a larger quantity of acid in the receiver4 ,it also implies the use of a larger digestion flask4 ,in fact it is now quite common to make the digestion in a special glass flask large enough to be used also for the distillation4 ,this saves one transfer of the material with the possible danger of loss attending it4 ,in the distillation it is a common practice1 especially in ,germany1 to do away with the condensing worm and to carry a long glass tube from the distilling flask directly into the acid on the receiver4 ,the only inconvenience in this method is the heating of the contents of the receiving flask1 but this is attended with no danger of loss of ammonia and the distillate1 on account of the high temperature it acquires1 is left free of carbon dioxid4 ,many of these minor changes have tended to simplify the process1 but without affecting the principle of the method in the least4 #b4 ,in the second place a class of changes may be mentioned in which there is a marked difference in the method of effecting the oxidation secured by the introduction of a substance1 usually a metal1 during the digestion for the purpose of accelerating the oxidation4 ,in the original process the only aid to oxidation was applied at the end of the digestion in the use of potassium permanganate4 ,in the modifications now under consideration a metallic oxid or metal is applied at the beginning of the digestion4 ,copper and mercury are the metals usually employed4 ,a separate paragraph will be given to the description of this modification known as the process of ,wilfarth4 #c4 ,the third class of changes is even more radical in its nature1 having for its object the adaptation of the moist combustion method to oxidized or mineral nitrogen4 ,the chief feature of this class of changes consists in the introduction of a substance rich in hydrocarbons1 and capable of easily forming nitro compounds1 for the purpose of holding the oxids of nitrogen which are formed during the combustion and helping finally to reduce them to the form of ammonia4 ,the chief varieties of this class of changes were proposed by ,asboth1 ,jodlbaur1 and ,scovell1 and will be fully set forth in separate paragraphs4 #ahh4 ,method of ,wilfarth4--,the basis of this modification as already noted rests on the fact that certain metallic oxids have the power of carrying oxygen1 and thus assisting in a katalytic way in the combustion of organic matter4#aef ,the copper and mercury oxids are best adapted for this purpose and experience has shown that mercuric oxid1 or even metallic mercury gives the best results4 ,the manipulation is carried out as follows3 ,from one to three grams of the sample1 according to its richness in nitrogen1 are heated with a mixture of twenty cubic centimeters of acid containing two-fifths fuming and three-fifths ordinary sulfuric acid4 ,to this is added about seven-tenths gram of mercuric oxid prepared in the wet way from a mercury salt free of nitrogen4 ,the combustion takes place in the usual kjeldahl flask4 ,if the boiling be continued until the liquid is entirely colorless1 final oxidation with potassium permanganate is unnecessary4 ,to save time the combustion may be stopped when a light amber color is reached1 and then the oxidation finished with permanganate4 ,before distilling1 a sufficient quantity of potassium sulfid is added to precipitate all the mercury as sulfid and thus prevent the formation of mercurammonium compounds which would produce a deficit of ammonia4 ,a convenient strength of the sulfid solution is obtained by dissolving forty grams of potassium sulfid in one liter of water4 ,bumping at the end of the distillation is not usual1 especially if potash-lye be used1 but should it occur it may be stopped by the addition of zinc dust4 ,only when a large excess of potassium sulfid is used is there an evolution of hydrogen sulfid1 the presence of which1 however1 does not influence the accuracy of the results4 ,the presence of mercuric sulfid in the solution tends to prevent bumping during the distillation1 but it is advisable1 nevertheless1 to use a little zinc dust4 ,other minor modifications consist of forming the acid mixture with equal volumes of concentrated and fuming sulfuric acid containing in one liter #ajj grams of phosphoric acid anhydrid1#aeg and using metallic mercury instead of mercuric oxid2 or a mixture of half a gram of copper sulfate and one gram of metallic mercury1#aeh or half a gram of copper oxid and a few drops of platinic chlorid solution containing #j4jd gram of platinum in a cubic centimeter4#aei #ahi4 ,modification of ,asboth4--,in order to adapt the moist combustion process to nitric nitrogen ,asboth proposed the use of benzoic acid4#afj ,for half a gram of saltpeter #a4ge grams of benzoic acid should be used4 ,at the end of the combustion the residual benzoic acid is oxidized by means of potassium permanganate with a subsequent reheating4 ,if the nitrogen be present as an oxid or as cyanid1 one gram of sugar is added4 ,the metallic element added is half a gram of copper oxid4 ,asboth also recommends that the soda-lye used in the distillation be mixed with sodium potassium tartrate for the purpose of holding the copper and manganese oxids in solution and thus preventing bumping4 ,the alkaline liquor contains in one liter #cej grams of the double tartrate and #cjj grams of sodium hydroxid4 ,the principle on which the use of benzoic acid rests is found in the fact that it easily yields nitro-compounds and thus prevents the loss of the nitrogen oxids1 these readily combining with the benzoic acid4 ,the nitro-compounds can be subsequently converted into ammonia by treatment with potassium permanganate4 ,the pyridin and chinolin groups of bodies do not yield all their nitrogen as ammonia by the above treatment4 ,the conclusions drawn by ,asboth from the analytical data obtained were3 7#a7 ,sugar should be used in the ordinary kjeldahl process in those cases where the nitrogen in the organic substance is present as oxids or as cyanogen4 7#b7 ,in the case of nitrates good results may be secured with benzoic acid but permanganate must be added at the end4 7#c7 ,the kjeldahl-wilfarth process can be applied with substances difficultly decomposed1 e4 g41 alkaloidal bodies4 #aij4 ,variation of ,jodlbaur4--,the benzoic acid method1 although a step forward1 is not entirely satisfactory in the treatment of nitrates by moist combustion4 ,jodlbaur has proposed to substitute for the benzoic1 phenolsulfuric acid4#afa ,from two to five-tenths gram of a nitrate are treated with twenty cubic centimeters of concentrated sulfuric and two and a half of phenolsulfuric acid1 together with three grams of zinc dust and five drops of a solution of platinic chlorid of the strength mentioned above4 ,the phenolsulfuric acid is prepared by dissolving fifty grams of phenol in #ajj cubic centimeters of strong sulfuric acid4 ,the combustion is continued until the solution is colorless1 which may take as much as five hours4 ,if phosphoric acid anhydrid be used as recommended above1 the time of the combustion may be diminished by one-half1 but in such a case the glass of the combustion flask is strongly attacked and is quite likely to break4 ,with substances very rich in nitrates it is advisable to rub them first with dry gypsum4 ,the theory of the process rests on the fact that by a careful admixture of a nitrogenous substance diluted with land plaster1 with phenolsulfuric acid1 it is possible to change the nitric acid into nitro-phenol1 and by the reducing action of zinc dust to change the nitro-product formed into amido-phenol4 ,this afterwards is transformed into ammonium sulfate by heating with sulfuric acid1 by which process1 at the same time1 all other nitrogenous compounds present in the substance1 as with ,kjeldahl's method1 likewise form ammonium sulfate1 only with the difference that addition of mercury is here absolutely necessary for the complete transformation of the slowly decomposed amido-phenol which again brings about the necessity of decomposing the nitrogenous mercury compounds formed in the solution by potassium sulfid1 which is added after or with the soda-lye4 #aia4 ,the ,dutch ,jodlbaur ,method4--,the ,royal ,experiment ,station of ,holland directs that the jodlbaur process be carried out as indicated below4#afb ,the reagents necessary are3 #a4 ,phenolsulfuric acid1 prepared by dissolving #ajj grams of pure crystallized phenol in pure sulfuric acid 7#a4hd7 and making up the solution to a liter with the same sulfuric acid3 #b4 ,zinc1 carefully washed and thoroughly dried3 #c4 ,sodium hydroxid solution1 the same as is used in the kjeldahl method3 #d4 ,potassium sulfid solution1 made by dissolving #cee grams of potassium sulfid 7,k,s71 or sodium sulfid solution1 made by dissolving #bej grams of sodium sulfid 7,na,s7 in a liter of water4 ,as apparatus1 are necessary oxidation flasks holding about #bjj cubic centimeters1 and distillation flasks holding about #gej cubic centimeters1 both of bohemian glass4 ,manipulation4--,weigh one gram of substance1 moisten it with water1 dry1 and introduce into an oxidation flask4 ,cover with fifteen cubic centimeters of phenolsulfuric acid and1 after cooling1 thoroughly mix by gently shaking4 ,after five minutes add from two to three grams of zinc in small proportions1 keeping the flask cool1 then twenty cubic centimeters of sulfuric acid1 and finally two drops of mercury4 ,boil the mixture till the fluid is colorless4 ,cool and dilute4 ,wash into a distillation flask and add an excess of sodium hydroxid solution and twenty-five cubic centimeters of the sodium 7or potassium7 sulfid solution4 ,distil and titrate as in the kjeldahl method4 #aib4 ,the ,halle-,jodlbaur ,method4--,at the ,halle station it is the uniform practice to mix the nitrate with gypsum before the combustion4#afc ,in the case of ,chile phosphates ten grams are rubbed with an equal amount of gypsum1 and two grams of the mixture1 equal to one gram of the nitrate1 taken for the determination4 ,in the case of saltpeter mixtures which contain over eight per cent of nitrogen1 one gram of the mixture with gypsum is taken1 of guanos one and a half grams1 and of lower forms of nitrates or mixtures thereof1 from three to five grams4 ,the sample1 as prepared above1 is treated with thirty cubic centimeters of a mixture of phenolsulfuric acid and phosphoric acid anhydrid4 ,the mixture is prepared by dissolving sixty-six grams of phenol and #bej grams of phosphoric anhydrid in strong sulfuric acid1 and1 after cooling1 mixing the two solutions and making the volume up to #a1fej cubic centimeters with pure sulfuric acid4 ,the mixture contains1 in thirty cubic centimeters1 one and two-tenths grams of phenol and four grams of phosphoric anhydrid4 ,in the use of phenolsulfuric acid the the presence of phosphoric anhydrid is indispensable in keeping the sulfuric acid water-free and in absorbing the water produced by the combustion4 ,the phenolsulfuric acid used contains only enough phenol to reduce half a gram of saltpeter4 ,the sample and acid mixture having been put in the combustion flask the latter is shaken1 at intervals1 for an hour1 and the contents cooled4 ,the conversion of the nitrates into nitro-phenol compounds is finished in this time1 and the next step consists in reducing these bodies to the amido-phenol group4 ,this is accomplished in the cold by nascent hydrogen produced by the addition of zinc dust to the mixture4 ,from one to three grams of the dust are to be used in proportion to the quantity of nitrates originally present4 ,the flask should be placed in a cooling mixture and the zinc dust added in small portions to prevent a too violent evolution of hydrogen4 ,after the reduction is ended the flask is allowed to stand for two hours1 after which the combustion1 distillation1 and titration are accomplished in the usual way4 ,on cooling1 after the end of the combustion1 the contents of the flask become solid4 ,they may be brought again into liquid state by shaking and gentle warming4 #aic4 ,the ,official ,kjeldahl ,method for ,nitric ,nitrogen4--,as has already been stated1 the presence of certain organic compounds1 rich in hydrocarbons1 permits the reduction of nitric nitrogen to ammonia by combustion with sulfuric acid4 ,benzol1 phenol1 and salicylic acid have all been used for this purpose4 ,the official chemists have adopted for their method the salicylic acid process first proposed by ,scovell4#afd ,besides the reagents and apparatus given under the ,kjeldahl method there will be needed3 7#a7 ,zinc dust3 ,this should be an impalpable powder2 granulated zinc or zinc filings will not answer4 7#b7 ,sodium thiosulfate3 7#c7 ,commercial salicylic acid3 ,it is found most convenient to prepare a solution of #cc4c grams of salicylic acid in one liter of the strongest sulfuric acid1 and keep it for use rather than to mix it for each combustion4 ,we prefer the thiosulfate process first mentioned below4 ,in the zinc dust method there has been noticed a tendency for the distillation flask to break just at the end of the process4 ,the ,manipulation4--,place from seven-tenths to three and five-tenths grams of the substance to be analyzed in a kjeldahl digesting flask1 add sixty cubic centimeters of sulfuric acid containing one gram of salicylic acid1 and shake until thoroughly mixed1 then add five grams of crystallized sodium thiosulfate2 or add to the substance thirty cubic centimeters of sulfuric acid containing two grams of salicylic acid1 then add gradually two grams of zinc dust1 shaking the contents of the flask at the same time4 ,finally place the flask on the stand for holding the digestion flasks1 where it is heated over a low flame until all danger from frothing has passed4 ,the heat is then raised until the acid boils briskly and the boiling continued until white fumes no longer pour out of the flask4 ,this requires about five or ten minutes4 ,add now approximately seven-tenths gram of mercuric oxid or its equivalent in metallic mercury1 and continue the boiling until the liquid in the flask is colorless or nearly so4 ,in case the contents of the flask are likely to become solid before this point is reached add ten cubic centimeters more of sulfuric acid4 ,complete the oxidation with a little potassium permanganate in the usual way1 and proceed with the distillation as described in the kjeldahl method4 ,the reagents should be tested by blank experiments4 #aid4 ,the ,gunning ,moist ,combustion ,process4--,the modification proposed by ,gunning was based upon the observation that in the ordinary kjeldahl process the excess of sulfur trioxid in the beginning of the operation soon escapes or unites with water in a form not easily decomposed4#afe ,during the progress of the combustion the acid diminishes in strength until it is below the concentration represented by the formula ,h,,so1 and in this diluted condition the oxidation takes place more slowly4 ,gunning proposes to avoid this difficulty by mixing potassium sulfate with the sulfuric acid4 ,this salt forms with the sulfuric acid1 acid salts which1 by heating1 lose water easier than acid and as is well known1 they not only act as decomposing and oxidizing media as well as sulfuric acid1 but even in a higher degree1 resembling the action of sulfuric acid at high temperatures and under pressure4 ,by heating this mixture of sulfuric acid and potassium sulfate with organic matters in an open vessel1 not only the water originally present1 but that which is formed during the oxidation is driven off without loss of acid4 ,for this reason instead of the oxidizing mixture becoming weaker1 the acid becomes stronger1 the boiling-point rises and this1 combined with the fluidity of the mass favors the decomposition and oxidation of the organic matter in a constantly increasing ratio4 ,the original mixture used by ,gunning had the following composition2 viz41 one part of potassium sulfate and two parts of strong sulfuric acid4 ,the substances are united by heat and1 on cooling1 are in a semi-solid state1 melting1 however1 easily on the application of heat and assuming a condition to be easily poured from vessel to vessel4 ,the quantity of the sample taken should vary in proportion to its nitrogenous content from half a gram to a gram4 ,the combustion takes place in flasks entirely similar to those used in the ordinary kjeldahl process4 ,in the case of liquids1 they should be previously evaporated to dryness before the addition of the oxidizing mixture4 ,at the beginning of the combustion there is a violent foaming attended with evolution of some acid and much water1 and afterwards of stronger acid4 ,this loss of acid should not be allowed to go far enough to produce too great concentration of the material in the flask4 ,one of the best ways to avoid it is to place a funnel in the flask covered with a watch-glass which will permit of the condensation and return of the escaping acid4 ,as soon as the foaming ceases1 the flame should be so regulated as to permit of the volatilized acid being condensed upon the sides of the flask4 ,in the end a colorless mass is obtained in which no metallic oxids are present1 and this mass can at once be diluted with water1 treated with alkali1 and distilled4 ,according to the nature of the substance from half an hour to an hour and a half are required for the complete combustion4 ,modifications of the ,gunning ,method4--,as in the case of the kjeldahl method1 numerous minor modifications of the gunning method have been made1 the most important of which relate to its application to substances containing nitrates4 ,in general the same processes are employed in this case as with the kjeldahl method4 ,one of the best modifications consists in the use of the mixture of salicylic and sulfuric acids followed by the addition of sodium thiosulfate or of potassium sulfate or sulfid4 ,these modifications will be given in detail under the official methods4 #aie4 ,reactions of the ,gunning ,process4--,the various reactions which take place during the combustion according to the gunning method have been tabulated by ,van ,slyke4#aff ,the first reaction to take place is the union of sulfuric acid and potassium sulfate to form potassium acid sulfate in accordance with the following equation3 7#a7 ,k,,so ,h,,so #b,,khso4 ,when heated1 the potassium acid sulfate decomposes1 forming potassium disulfate and water1 thus3 7#b7 #b,,khso ,k,s,o ,h,o4 ,the potassium disulfate at a higher temperature decomposes1 forming normal potassium sulfate and sulfur trioxid1 thus3 7#c7 ,k,s,o ,k,,so ,,so4 ,at a sufficiently high temperature the two preceding reactions may take place in one1 thus3 #b,,khso ,k,,so ,h,o ,,so4 ,at the temperature at which these reactions take place1 the water that is set free does not recombine with the sulfur trioxid nor with the sulfuric acid that is present in excess1 but is expelled from the mixture2 hence the mixture becomes more concentrated during the digestion4 ,the sulfur trioxid set free acts upon the organic matter in the powerful manner peculiar to it1 and the potassium sulfate formed in the last reaction above unites with another molecule of sulfuric acid1 and the same round of reactions is repeated continuously so long as there is an excess of free sulfuric acid present in the mixture4 ,as the liquid becomes more concentrated with the continuation of the digestion1 the boiling-point increases so that the effect is the same as heating under pressure4 ,the danger of too great concentration and risk of consequent loss of nitrogen is avoided by using increased proportions of sulfuric acid4 ,as compared with the kjeldahl the gunning method presents the following advantages3 7#a7 ,the gunning method requires fewer reagents4 ,as no form of mercury is used no potassium sulfid is needed1 and there is no risk of loss from the presence of mercurammonium compounds4 7#b7 ,the solution to which caustic soda is added is clear1 so that in neutralizing1 it is an easy matter to avoid great excess of alkali1 and so1 in most cases1 to avoid foaming and bumping in distillation4 7#c7 ,in the blank determinations less nitrogen is found in the reagents used in the gunning method4 ,in only one case was more nitrogen reported in a blank by this method2 in all the others the amount averaged considerably less4 #aif4 ,the ,official ,gunning ,method4--,in a digestion flask holding from #bej to #ejj cubic centimeters place from seven-tenths to two and eight-tenths grams of the substance to be analyzed1 according to its proportion of nitrogen4 ,then add ten grams of powdered potassium sulfate and from fifteen to twenty-five cubic centimeters 7ordinarily about twenty cubic centimeters7 of concentrated sulfuric acid4 ,conduct the digestion as in the kjeldahl process1 starting with a temperature below boiling-point and increasing the heat gradually until frothing ceases4 ,digest until colorless or nearly so4 ,do not add either potassium permanganate or potassium sulfid4 ,dilute1 neutralize1 and distil as in the kjeldahl method4 ,in neutralizing1 it is convenient to add a few drops of phenolphthalein indicator1 by which one can tell when the acid is completely neutralized1 remembering that the pink color1 which indicates an alkaline reaction1 is destroyed by a considerable excess of strong fixed alkali4 ,the distillation and titration are conducted as in the kjeldahl method4 ,in distilling1 the use of zinc or of any substance to prevent bumping or foaming is generally unnecessary1 if too great an excess of fixed alkali be avoided4 ,the amount of sulfuric acid recommended by ,gunning is two grams for each gram of potassium sulfate2 but ,voorhees has found that this mixture is so viscous as to cause troublesome foaming frequently1 and after cooling it cakes in a hard mass1 which may be difficult to redissolve4#afg ,to avoid foaming and caking1 he has found it an effective means to increase the amount of sulfuric acid used1 taking instead of two grams to one of potassium sulfate three or four grams of acid to one of potassium sulfate4 ,it is1 therefore1 suggested in carrying out the work1 to use from five to twenty-five cubic centimeters 7ordinarily about twenty cubic centimeters7 of sulfuric acid for ten grams of potassium sulfate4 ,in case the potassium sulfate is not free from nitrogen compounds1 one or two recrystallizations will make it pure4 #aig4 ,gunning ,method ,adapted to ,nitrates4--,the essential features of this modification are due to ,winton and ,voorhees4#afh ,the modifications of the kjeldahl method1 for similar purposes1 furnished the material details for the gunning modified process4 ,winton reports good results from digesting for two hours1 from half a gram to a gram of the sample with thirty cubic centimeters of sulfuric containing two grams of salicylic acid1 in a flask of half a liter capacity4 ,two grams of zinc dust are then slowly added1 with constant shaking1 and the flask heated1 at first gently1 until1 after a few minutes boiling1 dense fumes are no longer emitted4 ,three grams of potassium sulfate are next added and the boiling continued until the solution is colorless1 or if iron be present1 until a light straw color is produced4 ,on cooling1 when the mixture begins to solidify1 water is added with caution1 and afterwards sodium hydroxid1 and the ammonia is obtained by distillation4 ,in the process1 as conducted by ,voorhees1 about one gram of the sample is digested with ten grams of potassium sulfate and thirty cubic centimeters of sulfuric containing one gram of salicylic acid1 and three grains of zinc sulfid4 ,the heat is kept down until frothing ceases1 and then the mass kept in gentle ebullition until clear4 ,the distillation is accomplished with the usual precautions4 ,the voorhees process is superior to that recommended by ,winton in adding the potassium sulfate at the beginning of the combustion4 #aih4 ,official ,gunning ,method ,modified to ,include the ,nitrogen of ,nitrates4--,in a digestion flask holding from #bej to #ejj cubic centimeters1 place from seven-tenths to three and five-tenths grams of the substance to be analyzed1 according to the amount of nitrogen present4 ,add from thirty to thirty-five cubic centimeters of salicylic acid mixture1 namely1 thirty cubic centimeters of sulfuric to one gram of salicylic acid1 shake until thoroughly mixed1 and allow to stand from five to ten minutes1 with frequent shaking2 then add five grams of sodium thiosulfate and ten grams of potassium sulfate4 ,heat very gently until frothing ceases1 then strongly until nearly colorless4 ,dilute1 neutralize1 and distil the same as in the gunning method4 ,,determination ,,of ,,nitrogen ,,in ,,definite ,,forms ,,of ,,combination4 #aii4 ,introductory ,considerations4--,in the foregoing pages has been given a summary of the methods most in vogue for the estimation of nitrogen in fertilizers and fertilizing materials4 ,there are many cases in which the analyst may have to deal with a definite chemical compound1 and where a modified or shorter method may be used4 ,there are other cases in which the nitrogen may be present in two or three definite forms1 as in artificially mixed fertilizers1 and where it is desirable to show the proportions in which the various forms are present4 ,for these reasons it is necessary to be able to use methods by which the percentage of nitrogen in its various forms may be relatively as well as absolutely determined4 ,such a case would be presented for instance1 in that of a fertilizer containing dried blood1 sodium nitrate1 and ammonium sulfate4 ,it is evident here that the total nitrogen could be determined by the volumetric method by combustion with copper oxid1 or by the moist combustion process adapted to nitric nitrogen1 but the method of determining the percentage of each constituent has not yet been described4 ,we have to deal here with a case entirely similar to that of phosphoric acid in a superphosphate4 ,there is no doubt whatever of the uneven assimilability of the different forms of nitrogen4 ,a nitrate1 for instance1 is already in condition for assimilation by plants4 ,an ammoniacal salt is only partly changed to a state suited to plant nutrition while organic nitrogen is forced to undergo a complete transformation before it becomes available to supply the needs of the growing plant4 ,it is important1 therefore1 equally to the analyst1 the merchant1 and the agronomist1 to know definitely the forms of combination in which the nitrogen exists and the relative proportion of the different combinations4 #bjj4 ,nitrogen as ,ammonia4--,the most frequent form in which nitrogen as ammonia is used for fertilizing is as sulfate4 ,the method of determination to be described is1 however1 equally applicable to all ammonia salts4 ,when no other form of nitrogenous compound is present the ammonia can be easily and directly determined by distillation with soda- or potash-lye1 as described in the final part of the moist combustion process4 ,to one gram of the ammonia salt add from #bjj to #cjj cubic centimeters of water and thirty grams of the soda-lye used in the moist combustion process2 distil1 collect the ammonia1 and titrate the excess of sulfuric acid exactly as there described4 ,fresenius recommends that the ammonia expelled by distillation be taken up by one-fifth normal sulfuric acid1 the excess of which is titrated with one-fifth normal soda1 using phenolphthalein as an indicator4 ,if the distillate1 on examination1 be found to contain thiocyanate1 soda-lye cannot be used for the expulsion of ammonia1 but1 in its place1 caustic magnesia is applied4 ,in all cases where organic matter containing nitrogen is present1 caustic magnesia must be substituted for the soda solution4 ,the magnesia must be added in sufficient excess and the distillation continued a little longer than is necessary when soda-lye is used4 ,otherwise the details of the operation are the same4 ,in a mixed fertilizer containing organic nitrogen and ammonia salts1 the total nitrogen can be determined by the moist combustion process1 and the ammoniacal nitrogen by distillation with magnesia4 ,the difference between the two results will give the nitrogen due to the organic matter4 ,to avoid any danger whatever of decomposing organic nitrogenous compounds1 the ammonia may be determined in the cold by treatment with soda-lye1 under a bell-jar containing some set sulfuric acid4 ,the operation must be allowed to continue for many days4 ,even at the end of a long time it will be found that some ammonia is still escaping4 ,it may therefore be finally inferred that all the nitrogen as ammonia is not obtained by this process1 or that even magnesia may gradually convert other nitrogenous compounds into ammonia4 ,in this connection the methods of determining ammonia in soils #djf1 #djg1 and #djh of volume one may be consulted4 #bja4 ,method of ,boussingault4--,the official ,french method is essentially the original method of ,boussingault with slight modifications4 ,it is conducted as follows3#afi ,in case the sample is ammonium sulfate about half a gram is placed in a flask of half a liter capacity1 together with #cjj cubic centimeters of distilled water and two grams of caustic magnesia4 ,the flask is connected with a condenser of glass or metal which ends in a tube drawn out to a point and dipping beneath the set acid in the receiver in the usual way4 ,the acid is colored with litmus or lacmoid tincture4 ,the distillation is continued until about #ajj cubic centimeters have gone over4 ,the receiver is then removed with the usual precautions and the residual acid titrated4 ,suppose twenty cubic centimeters of normal acid have been employed and twelve and a half cubic centimeters of normal alkali be necessary to neutralize the excess of the acid4 ,then the nitrogen is found by the following equations3 #bj4j - #ab4e #g4e and #g4e #j4jad #j4aje gram weight of nitrogen found4 ,then #j4aje #ajj #e #ba4jj per cent of nitrogen found4 ,the distilling apparatus of ,aubin is preferred by the ,french chemists1 an apparatus so arranged with a reflux partial condenser1 that nearly all the aqueous vapor is returned in a condensed state to the flask while the ammonia1 on account of its great volatility1 is carried over into the receiver4 ,to avoid the regurgitation which might be caused by the concentrated ammonia gas coming in contact with the acid the separable part of the condensing tube is expanded into a bulb large enough to hold all the acid which lies above its mouth4 ,by the means of this apparatus the ammonia is all collected in the standard acid without greatly increasing its volume and the titration is thus rendered sharper4 ,the employment of caustic magnesia has the advantage of not decomposing any organic matters or cyanids that may be present4 ,if the sample under examination hold part of its ammonia as ammonium magnesium phosphate it will be necessary first to treat it with sulfuric acid in order to set the ammonia free and then to use enough of the magnesium oxid to neutralize the excess of the sulfuric acid and still supply the two grams necessary for the distillation4 ,when the sample contains a considerable quantity of organic matter it sometimes tends to become frothy towards the end of the distillation4 ,this trouble can be avoided by introducing into the flask one or two grams of paraffin4 ,where carbon dioxid is given off during the distillation the contents of the receiver must be boiled before titration1 or else lacmoid must be used as an indicator instead of litmus4 #bjb4 ,determination of ,thiocyanates in ,ammoniacal ,fertilizers4--,the extended use of ammonium sulfate as a fertilizer renders it important to determine the actual constituents which may be present in samples of this material4 ,the following bodies have been found in commercial ammonium sulfates3 ,sulfuric acid1 chlorin1 ammonia1 thiocyanic acid1 potash1 soda1 lime and iron oxid4 ,these are found in the soluble portions4 ,in the insoluble portions have been found silica1 sulfuric acid1 lime1 magnesia and iron oxid4 ,a sample of commercial ammonium sulfate analyzed by ,jumeau contained the following substances3#agj ,per cent4 ,moisture #aj4eaji ,ammonium sulfate #fg4hdec ,ammonium thiocyanate #i4cice ,sodium sulfate #i4bdbi ,potassium sulfate #j4iggd ,calcium sulfate #j4fhjj ,iron thiocyanate #j4ejjj ,magnesium chlorid traces ,silica #j4jhcj ,undetermined #j4gfgj ,the determination of the thiocyanic acid in the thiocyanate is generally made by the oxidation of the sulfur to sulfuric acid and its subsequent weighing in the form of barium sulfate4 ,jumeau has modified the method by determining the amount of the thiocyanate by means of a titrated liquid4 ,the method is practiced as follows3 ,a solution of ammonium thiocyanate is prepared1 containing eight grams of this salt per liter1 and its exact content of thiocyanate is rigorously determined by titration with silver nitrate or by the weight of the barium sulfate produced after the oxidation of the sulfur4 ,ten cubic centimeters of the titrated liquor are taken and diluted with water to about #ajj cubic centimeters and ten cubic centimeters of pure sulfuric acid added4 ,afterward1 drop by drop1 a solution of potassium permanganate is added1 containing about ten grams of that salt per liter4 ,the permanganate is instantly decolorized4 ,there is an evolution of hydrocyanic acid as the thiocyanate passes to the state of sulfuric acid4 ,a single drop in excess gives to the mixture the well-known rose coloration of the permanganate solution which persists for several hours4 ,the number of cubic centimeters necessary to produce the persistent rose tint is noted and the same operation is carried on with from one-half to one gram of the unknown product which is to be assayed4 ,a simple proportion indicates the content of the thiocyanate in the unknown body4 ,the process is of great exactitude and permits the rapid determination of thiocyanic acid in the presence of chlorids1 cyanids1 etc41 which remain without action upon the permanganate4 ,in case chlorids and cyanids are absent the thiocyanate can be determined directly by silver nitrate either by weighing the precipitate or by the process of ,volhardt based upon the precipitation of the silver by thiocyanate in the presence of a ferric salt4 ,the end of the reaction is indicated by the red coloration which the liquid shows when the thiocyanate is in excess4 #bjc4 ,separation of ,albuminoid from ,amid and ,other ,forms of ,nitrogen in ,organic ,fertilizers4--,it may be of interest to the dealer1 farmer1 and analyst1 to discriminate between the albuminoid and other nitrogen in fertilizers1 such as oil-cakes4 ,the final value of the nitrogen for plant nourishment is not greatly different1 but the immediate availability for nitrification is a matter of some importance4 ,the most convenient process in such a case is the copper hydroxid separation process as improved by ,stutzer4#aga ,the process is conveniently carried out in accordance with the method prescribed by the official chemists4#agb ,total ,crude ,protein4--,determine nitrogen as directed for nitrogen in fertilizers and multiply the result by #f4be for the crude protein4 ,determination of ,albuminoid ,nitrogen4--,to from seven-tenths to eight-tenths gram of the substance in a beaker add #ajj cubic centimeters of water1 heat to boiling1 or in the case of substances rich in starch1 heat on the water-bath ten minutes1 and add a quantity of cupric hydroxid mixture containing from one-half to six-tenths gram of the hydroxid2 stir thoroughly1 filter when cold1 wash with cold water1 and put the filter and its contents into the concentrated sulfuric acid for the determination of nitrogen4 ,the filter-papers used must be practically free of nitrogen4 ,add sufficient potassium sulfid solution to completely precipitate all copper and mercury1 and proceed as in the moist combustion process for nitrogen4 ,if the substance examined consist of seed of any kind1 or residues of seeds1 such as oil-cake or anything else rich in alkaline phosphates1 add a few cubic centimeters of a concentrated solution of alum just before adding the cupric hydroxid1 and mix well by stirring4 ,this serves to decompose the alkaline phosphates4 ,if this be not done cupric phosphate and free alkali may be formed1 and the protein-copper may be partially dissolved in the alkaline liquid4 ,cupric ,hydroxid4--,prepare the cupric hydroxid as follows3 ,dissolve #ajj grams of pure cupric sulfate in five liters of water1 and add twenty-five cubic centimeters of glycerol2 add a dilute solution of sodium hydroxid until the liquid is alkaline2 filter1 rub the precipitate up with water containing five cubic centimeters of glycerol per liter1 and then wash by decantation or filtration until the washings are no longer alkaline4 ,rub the precipitate up again in a mortar with water containing ten per cent of glycerol1 thus preparing a uniform gelatinous mass that can be measured out with a pipette4 ,determine the quantity of cupric hydroxid per cubic centimeter of this mixture4 ,amid ,nitrogen4--,the albuminoid nitrogen determined as above subtracted from the total1 gives that part of the organic nitrogen existing in the sample as amids and in other allied forms4 #bjd4 ,separation of ,nitric and ,ammoniacal from ,organic ,nitrogen4--,the nitrogen being present in three forms1 viz41 organic1 ammoniacal1 and nitric1 the separation of the latter two may be accomplished by the following procedure3#agc ,one gram of the fertilizer is exhausted on a small filter with a two per cent solution of tannin1 using from thirty to forty cubic centimeters in small portions4 ,this is sufficient to dissolve all the nitrates and the greater portion of the ammoniacal salts1 while the tannin renders insoluble all the organic nitrogenous compounds4 ,the filter and its contents are treated for nitrogen by the kjeldahl process4 ,when the distillation and titration are completed the solution obtained by the aqueous tannin is added to the distilling flask and the operation continued4 ,this represents the ammoniacal nitrogen4 ,the nitric acid is estimated by the ferrous iron or other appropriate method in another portion of the substance4 ,this method can be used even when the fertilizer contains ammonium magnesium phosphate4 ,in this case digest one gram for fifteen hours in dilute soda-lye solution1 which easily dissolves the ammonium magnesium phosphate4 ,filter and wash the insoluble part with the tannin solution4 ,the residue is treated as above4 ,the filtered solution distilled with soda-lye furnishes the ammonia4 ,the nitrates are estimated by one of the methods above mentioned4 #bje4 ,nitric ,nitrogen4--,the methods of estimating nitric nitrogen1 both when present in weighable quantities and as mere traces have been sufficiently described in the first volume4 ,for convenience1 however1 the standard methods of procedure will be given here4 ,the moist combustion methods adapted to nitrates and the volumetric copper oxid process have already been described4 ,of the reduction methods the process of ,ulsch is one of the easiest of application and also reliable4 ,as practiced by the official chemists the manipulation is conducted as described in the first volume1 page #eci4 #bjf4 ,ulsch ,method1 ,applicable to ,mixed ,fertilizers4--,the method of ,ulsch which is found to give good results with pure nitrates or with nitrates in the absence of other forms of nitrogen may also be adapted to mixed fertilizers containing nitrogen in more than one form4 ,street has developed such a method and shown1 by analytical data1 that it is applicable in a great number of cases4#agd ,the process is based on the substitution of magnesia for soda in the distillation and is carried on as follows3 ,place one gram of the sample in a half liter flat-bottomed flask4 ,add about thirty cubic centimeters of water1 one gram of reduced iron1 and ten cubic centimeters of sulfuric acid diluted with an equal volume of water1 shake well1 and allow to stand for a short time4 ,this will remove the danger of an explosion caused by the otherwise violent action which takes place4 ,close the neck of the flask with a rubber stopper through which passes a glass dropping-bulb filled with water4 ,the flask having been stoppered1 place it on a slab to which a moderate heat is applied4 ,allow the solution to come slowly to a boil and then boil for five minutes and cool4 ,add about #ajj cubic centimeters of water1 a little paraffin1 and about five grams of magnesium oxid4 ,boil for forty minutes1 after which time all the ammonia will be distilled1 and collect the ammonia in set acid4 ,the magnesia causes a slight frothing1 which can easily be controlled by adding a little paraffin and by bringing to a boil very gradually4 ,fully forty minutes are necessary to distil all the ammonia4 ,tests were made after thirty minutes boiling and traces of ammonia were still found2 after forty minutes these traces entirely disappeared4 ,the method is a quick one4 ,one man can easily do six determinations at a time1 and these six determinations can be made in but a little over an hour4 ,magnesia gives results closely agreeing with theory and causes a very slight frothing1 which can be easily controlled4 ,one gram of reduced iron is sufficient in all ordinary complete fertilizers4 ,magnesia is preferred to caustic soda in the distillation because it produces less frothing and by reason of the danger of some of the soda-lye being carried over mechanically and thus tending to produce an error of a plus nature4 ,in the use of magnesia1 assurance must be had that it is strongly in excess4 ,being less active in its effects a longer time for the distillation must be taken than when soda-lye is used4 ,the modified ulsch method just described is recommended provisionally and with the expectation that each analyst will ascertain its true merits before allowing it to displace longer approved processes4 #bjg4 ,method of ,schlsing-,wagner4--,the ,schlsing-,wagner method for estimating nitrogen in the nitrates of fertilizers is carried out at the ,halle ,experiment ,station as follows3#age ,a flask1 figure #ad1 of about #bej cubic centimeters capacity1 is provided with a rubber stopper with two holes4 ,through one of them is passed the stem of a funnel carrying a glass stop-cock4 ,the other carries a delivery-tube leading to the receiving vessel4 ,the end of the delivery tube is bent so as to pass easily under the mouth of the measuring burette and is covered with a piece of rubber tubing4 ,fifty cubic centimeters of saturated ferrous chlorid solution and the same quantity of ten per cent hydrochloric acid are placed in the flask4 ,the ferrous chlorid solution is obtained by dissolving nails or other small pieces of iron in hot hydrochloric acid and it is kept in glass stoppered flasks1 of about fifty cubic centimeters capacity1 entirely filled4 ,the content of one flask is enough for about twelve determinations and by using the whole content of a flask as soon as possible after opening1 any danger of oxidation which would take place in a large flask frequently opened is avoided4 ,illustration3 ,,figure #ad4 ,,schl,,sing-,,wagner ,,apparatus4 ,the contents of the flask are boiled until all the air is driven off4 ,the delivery-tube is then placed under the measuring-tube1 which is filled with forty per cent potash-lye4 ,the measuring-tube is previously almost filled with potash-lye and then a few drops of water added and the tube covered with a piece of filter-paper4 ,by a careful and quick inversion the measuring-tube can be brought into the vessel receiving it without any danger of air entering4 ,the boiling is continued for some time and when no more air escapes1 the end of the delivery-tube is brought into another freshly filled measuring-tube and the estimation is commenced4 ,ten cubic centimeters of a normal saltpeter solution1 containing two and a half grams of pure sodium nitrate in #ajj cubic centimeters are placed in the funnel and1 with continued boiling1 allowed to pass1 drop by drop1 into the flask4 ,when almost all has run out the funnel is washed three times with ten cubic centimeters of ten per cent hydrochloric acid and this is allowed to pass1 drop by drop1 into the flask4 ,when no more nitric oxid is evolved the measuring-tube is transferred to a large jar filled with distilled water4 ,the solution of the substance to be examined should be taken in such quantity as will give about the same quantity of gas as is furnished by the ten cubic centimeters test nitrate solution before described2 viz41 about seventy cubic centimeters4 ,eight or ten determinations can be made1 one following the other1 and at the end another determination with normal sodium nitrate solution should be made as a check4 ,at the end of the operation all of the measuring-tubes are in the large jar filled with distilled water4 ,the temperature of the surrounding water will soon be imparted to the contents of each tube and the volume of nitric oxid is read by bringing the level within and without the measuring-tube to the same point4 ,the percentages are calculated for the given temperature and barometer pressure in the usual way2 or to avoid computation the volume can be compared directly with the volume furnished by a normal nitrate solution1 which is a much simpler method4 #bjh4 ,schmitt's ,modified ,method4--,the method is a modification of that already described by the author in which a mixture of powdered zinc and iron is used as a reducing agent4#agf ,the process is carried out as follows3 ,ten grams of the nitrate are dissolved and the volume made up to half a liter4 ,ten cubic centimeters of glacial acetic acid and ten grams of the fine metallic powder1 iron and zinc1 are placed in a flask of a capacity of about three-quarters of a liter and twenty-five cubic centimeters of the solution of the nitrate added4 ,the flask is covered during the reduction to prevent loss by spraying1 and after the solution is complete1 which is the case in about ten minutes1 the contents of the flask are diluted with from #bjj to #cjj cubic centimeters of water1 thirty cubic centimeters of caustic soda of #a4be specific gravity added1 and the whole distilled as in the kjeldahl process4 ,it must be noted that it is essential that the iron be finely divided2 it is mixed with the powdered zinc in equal parts4 ,the total nitrogen can be determined in guanos and nitrate mixtures by the following simple alteration in procedure3 ,one gram of the substance is dissolved in water1 five cubic centimeters of glacial acetic acid1 and from two to three grams of the mixed metallic powder added1 and the whole gently heated for ten or fifteen minutes4 ,after the contents of the flask have cooled1 twenty-five cubic centimeters of sulfuric acid are cautiously added in small portions1 undue frothing being restrained by the addition of a fragment of paraffin wax4 ,the acetic acid is then driven off by heating1 and the remaining contents of the flask boiled until the organic matter is completely decomposed1 as in the kjeldahl process4 ,about two hours boiling is required4 ,neutralization and distillation are then practiced as in the ordinary manner4 ,the method is also applicable to the determination of nitrates in drinking water1 provided nitrites and ammonia be absent4 #bji4 ,krger's ,method for ,nitric ,acid4--,about three-tenths gram of the substance dissolved in water is mixed with twenty cubic centimeters of a hydrochloric acid solution of stannous chlorid holding #aej grams of tin per liter4#agg ,one and a half grams of spongy tin prepared by the action of zinc on stannous chlorid are added4 ,the flask containing the mixture is heated until the tin is dissolved1 by which time the nitric acid is completely reduced4 ,the subsequent distillation and titration are accomplished as usual4 ,in the case of nitro and nitroso compounds1 after the solution of the tin1 twenty cubic centimeters of sulfuric acid are added and heated until sulfuric vapors escape4 ,after cooling1 the amido substances formed are oxidized by potassium bichromate before the distillation takes place4 ,krger also estimates the nitrogen in benzol1 pyridin1 and chinolin derivatives by dissolving them in sulfuric acid1 using from two-tenths to eight-tenths of a gram of the alkaloidal bodies and1 after cooling the solution1 oxidizing by adding finely powdered potassium bichromate4#agh ,about half a gram more of the potassium bichromate should be used than is necessary for the oxidation of the substances in solution4 ,the entire oxidation does not consume more than from fifteen to thirty minutes4 ,,sodium ,,nitrate4 #baj4 ,functions of ,sodium ,nitrate4--,practically the only form of oxidized nitrogen which is of importance from an agronomic point of view is sodium nitrate1 often known in commerce by the name ,chile saltpeter4 ,applied to a growing crop it at once becomes dissolved at the first rainfall or by the natural moisture of the soil4 ,it carries thus to the rootlets of plants a supply of nitrogen in the most highly available state4 ,there is perhaps no other kind of plant food which is offered to the living vegetable in a more completely predigested state1 and none to which a quicker response will be given4 ,by reason of its high availability1 however1 it must be used with care4 ,a too free use of such a stimulating food may have1 in the end1 an injurious effect upon the crop1 and is quite certain to lead to the waste of a considerable portion of expensive material4 ,for this reason sodium nitrate should be applied with extreme care1 in small quantities at a time and only when it is needed by the growing crop4 ,it would be useless1 for instance1 to apply this fertilizer in the autumn with the expectation of its benefitting the crop to a maximum degree the following spring4 ,again1 if the application of this salt should be made just previous to a heavy rain almost or quite the whole of it would be removed beyond the reach of the absorbing organs of the plant4 ,when once the nitric acid has been absorbed by the living rootlet it is held with great tenacity4 ,living plants macerated in water give up only a trace of nitric acid1 but if they be previously killed with chloroform the nitric acid they contain is easily leached out4 ,the molecule of sodium nitrate is decomposed in the process of the absorption of the nitric acid4 ,the acid enters the plant organism and the soda is excreted and left to combine with the soil acids4 ,the nascent soda may thus play a role of some importance in decomposing particles of minerals containing potash or phosphoric acid4 ,it is probable that the decomposition of the sodium nitrate takes place in the cells of the absorbing plant organs for it is difficult to understand how it could be accomplished externally4 ,while the soda therefore is of no importance as a direct plant food it can hardly be dismissed as of no value whatever in the process of fertilization4 ,many of the salts of soda as1 for instance1 common salt1 are quite hygroscopic and serve to attract moisture from the air and thus become carriers of water between the plant and the air in seasons of drought2 and sodium nitrate itself is so hygroscopic as not to be suited to the manufacture of gunpowder4 ,to recapitulate3 ,the chief functions of sodium nitrate are to give to the plant a supply of oxidized nitrogen ready for absorption into its tissues and incidentally to aid1 by the residual soda1 in the decomposition of silt particles containing potash or phosphoric acid and in supplying to the soil salts of a more or less deliquescent nature4 #baa4 ,commercial ,forms of ,chile ,saltpeter4--,the ,chile saltpeter of commerce may reach the farmer or analyst in the lumpy state in which it is shipped or as finely ground and ready for application to the fields4 ,unless the farmer is provided with means for grinding1 the latter condition is much to be preferred4 ,it permits of a more even distribution of the salt and thus encourages economy in its use4 ,for the chemist also it is advantageous to have the finely ground material1 which condition permits more easily a perfect sampling1 a process which1 with the unground salt1 is attended with no little difficulty4 #bab4 ,percentage of ,nitrogen in ,chile ,saltpeter4--,chemically pure sodium nitrate contains #af4di per cent of nitrogen4 ,the salt of commerce is never pure4 ,it contains moisture1 potash1 magnesia1 lime1 sulfur1 chlorin1 iodin1 silica and insoluble materials1 and traces of other bodies4 ,the value of the salt depends1 therefore1 not only on the market value of nitrogen at the time of sale1 but also on its content of nitrogen4 ,the nitrate of commerce varies greatly in its nitrogen content and is sold on a guaranty of its purity4 ,the best grades range in nitrogen from fifteen to sixteen per cent4 ,the content of nitrogen has long been estimated in the trade by determining the other constituents and counting the rest as nitrogen4 ,this practice arose in former times when no convenient method was at hand for determining nitric nitrogen4 ,the process is tiresome and unreliable because all errors of every kind are accumulated in the nitrogen content1 but inasmuch as the method is still required by many merchants1 the analyst should be acquainted with it1 and it is therefore given further along4 ,the usual methods for determining nitric nitrogen may be applied in all cases where samples of sodium nitrate are under examination1 but some special processes are added for convenience4 #bac4 ,adulteration of ,chile ,saltpeter4--,the analyst is the only protector of the farmer in guarding against the practice of adulteration of sodium nitrate aside from the honesty of the dealer4 ,even the honest dealer is compelled to protect himself against fraud1 and therefore1 the world over1 commerce in this fertilizer is now conducted solely on the analyst's certificate4 ,happily1 therefore1 adulteration is almost unknown because it is certain to be detected4 ,formerly1 the saltpeter was adulterated with common salt1 or low grade salts from the potash mines2 but it is an extremely rare thing now to find any impurities in the salts other than those naturally present4 ,in every case the analyst may grow suspicious when he finds the content of nitrogen in a sample to fall below thirteen per cent4 ,it must not be forgotten1 however1 that some potassium nitrate may be present in the sample1 and since that salt contains only #ac4hg per cent of nitrogen its presence would tend to lower the value of the fertilizer2 but although the potash itself is a fertilizer of value it is not worth more than one-third as much as nitrogen4 ,in all cases of suspected adulteration1 it is advisable to make a complete analysis4 ,the results of this work will1 as a rule1 lead the analyst to a correct judgment4 ,illustration3 ,,figure #ae4 ,,halle ,,nitric ,,acid ,,apparatus4 #bad4 ,the ,halle ,zinc-,iron ,method4--,for determining the nitrogen in ,chile saltpeter the reduction method is conducted at the ,halle ,station as follows3#agi ,ten grams of the nitrate are dissolved in one liter and fifty cubic centimeters of the solution corresponding to half a gram of the sample1 taken for each determination4 ,the apparatus employed is shown in ,fig4 #ae4 ,a mixture of five grams of zinc dust and an equal weight of iron filings is employed as the source of hydrogen4 ,the reduction takes place in an alkaline medium secured by adding to the other materials mentioned1 eighty cubic centimeters of soda-lye of #a4cj specific gravity4 ,the respective quantities of iron and zinc may be measured instead of weighed1 as exact proportions are not required4 ,after the addition of all the materials the flask is allowed to stand for an hour at room temperature4 ,the distillation is then commenced and continued until at least #ajj cubic centimeters of distillate have been collected4 ,the receiving flasks are ordinary erlenmeyers1 each of which contains twenty cubic centimeters of set sulfuric acid1 as in the usual kjeldahl process4 ,the flasks are sealed with a few drops of water by the device shown in the figure4 ,after the end of the operation the water in each one is washed back into its proper flask with freshly boiled water4 ,during the vigorous evolution of hydrogen1 at the beginning of the operation1 some kind of a safety arrangement is necessary to prevent the particles of soda-lye being carried over by the bubbles of that gas4 ,the siphon bulb shown in the figure is found effective for this purpose4 ,in this operation better results are obtained by condensing the escaping steam1 and for this reason the block tin tubes are conducted through a tank supplied with a current of cold water4 ,the ends of the tubes should not dip below the surface of the liquid in the receivers4 ,when the condensed liquid collects in considerable quantities in the safety tube the lamp should be extinguished under the flask1 which permits the return of the liquid to the flask by means of the siphon4 ,this should be done two or three times during the progress of the distillation to prevent a too high concentration of the soda-lye1 thus endangering the flask4 ,the excess of the acid in the receiver is determined by titration1 as in the regular kjeldahl method4 ,blank determinations should be made1 from time to time1 and corrections made in harmony therewith4 #bae4 ,method of the ,french ,sugar ,chemists4--,the nitrogen in ,chile saltpeter is estimated by the ,french chemists according to the method of ,schlsing1 described in the first volume1 page #ejj4 ,in order to avoid the trouble of calculating the results from the volume of nitric oxid obtained1 a determination is first made with a pure salt1 sodium or potassium nitrate4 ,the volume of gas obtained is read directly without correction and taken for direct comparison4 ,the comparison is made as follows3 ,the solutions of the pure salts and of the sample to be analyzed are made of such a strength as to contain sixty-six grams of sodium nitrate1 or eighty grams of potassium nitrate1 in a liter4 ,five cubic centimeters of such a solution will yield a little less than #ajj cubic centimeters of nitric oxid under usual conditions4 ,let the volume of gas obtained with the pure salt be v2 and that with the sample be v4 ,the calculation is then made from the equation3 v x ---- ----4 v #ajj ,example3 ,let ninety-five cubic centimeters be the volume of gas from five cubic centimeters of the pure salt 7sodium nitrate71 and #ia4e cubic centimeters be the volume of gas from five cubic centimeters of the sample2 then #ia4e x ---- ----1 whence x #if4ca4 #ie #ajj ,hence the sample analyzed contains #if4ca per cent of sodium nitrate4 ,since the pure sodium nitrate contains #af4dg per cent of nitrogen the sample under examination would contain #af4dg #if4ca ------------- #ae4hf per cent4 #ajj ,it is evident that this comparative method is quite easy of application when the sample under examination has no other nitrate in it except that combined with the one base4 #baf4 ,volumetric ,method of ,gantter4--,the process proposed by ,gantter for determining the nitrogen1 volumetrically1 in ,chile saltpeter and other nitrates is based on the following principles3#ahj 7#a7 ,if a nitrate be heated in contact with sulfuric and phosphorous acids1 nitrous acid will be formed4 7#b7 ,if nitrous acid be boiled with ammonium chlorid1 nitrogen will be quantitatively evolved from both compounds4 ,these processes are illustrated by the following formulas3 7a7 ,n,o ,p,o ,n,o ,p,o4 7b7 ,n,o #b,,nh,cl #b,n #c;,h,o #b;,h,cl4 ,illustration3 ,,figure #af4 ,,gantter',s ,,nitrogen ,,apparatus4 ,it is seen from the above that the nitrate will give1 by this treatment1 double the volume of nitrogen which it contains4 ,in practice1 the two reactions may be secured in one operation by warming the nitrate solution slowly with sulfuric and phosphorous acids and ammonium chlorid4 ,the nitric acid1 as it becomes free1 gives a part of its oxygen to the phosphorous compound1 and the nitrous acid1 in a nascent state1 is at once reduced by the ammonium chlorid4 ,there are two sources of error which must be guarded against in the work2 a portion of the nitrogen may escape reduction to the elementary state1 or some of the nitrate may fail to be decomposed4 ,these errors are easily avoided if the reaction be begun slowly1 so that the evolution of gas may be gradual4 ,the temperatures at first should1 therefore1 be kept as low as possible4 ,the development of red fumes1 showing the presence of undecomposed nitrogen oxids1 shows that the results will be too low4 ,it is necessary1 also1 to provide for the absorption of the hydrochloric acid which is formed4 ,the reaction is very conveniently conducted in the apparatus shown in ,fig4 #af4 ,the decomposition takes place in the flask ,a and the mixed gases pass into the absorption bulb ,c4 ,the delivery-tube is very much expanded1 as shown in the figure1 so that no soda-lye can enter ,a during the cooling of the flask4 ,the absorption bulb is connected with ,a and ,b by the tubes a and b as shown4 ,the tube d connects the apparatus with the gasvolumeter4#aha ,the bulb ,b serves as a pipette for the introduction of the decomposing acid4 ,the operation is conducted as follows3 ,three cubic centimeters of the nitrate solution1 containing no more than #cjj milligrams of substance1 are placed in the flask ,a with half a gram each of crystallized ammonium chlorid and phosphorous acid4 ,in the bulb ,b are placed seven cubic centimeters of sulfuric acid to which has been added one-third its volume of water4 ,two cubic centimeters of acid are allowed to flow from ,b into ,a4 ,the apparatus is brought to a constant temperature by being immersed in a large cylinder1 ,e1 containing water at a temperature which can easily be controlled4 ,when this constant temperature has been reached the apparatus is taken from the cooling cylinder which contains also a smaller cylinder1 ,d1 nearly filled with water and connected through f with the measuring apparatus ,m4 ,the barometer-tube ,f is half filled with colored water so that the pressure may be equalized before and after the operation4 ,the flask ,a is warmed very gently at first1 and the nitrogen evolved is conducted into ,d driving an equivalent volume of water into ,m4 ,the evolution of the gas must be carefully controlled and the heat at once removed if it become too rapid4 ,the appearance of a red color shows the evolution of oxids of nitrogen rendering the analysis inexact4 ,when the evolution of nitrogen has nearly ceased the lamp is removed and some more sulfuric acid allowed to flow into ,a from ,b1 after which ,a is again heated1 this time to the boiling-point4 ,all vapors of hydrochloric acid produced are absorbed by the soda-lye in ,c4 ,the boiling is continued a few minutes1 but not long enough to darken the liquid in ,a4 ,after replacing the apparatus in the cylinder ,e and bringing both temperature and pressure to the same point as before the beginning of the operation1 the volume of nitrogen evolved is determined by measuring the water in ,m4 ,the apparatus is first set by using pure potassium or sodium nitrate4 ,since the temperature and pressure do not vary much within an hour or two the volume of water obtained with a sample of white saltpeter can be compared directly with that given off by the same weight of a pure potassium or sodium nitrate without correction4 ,example4--,two hundred and fifty milligrams of potassium nitrate1 containing #cd4fbe milligrams of nitrogen1 displaced in a given case sixty cubic centimeters of water2 therefore one cubic centimeter of water equals #j4egh milligram of nitrogen4 ,if #bhi instead of #bej milligrams be taken then the number of cubic centimeters of water displaced divided by five will give the per cent of nitrogen4 #bag4 ,method of ,difference4--,in the analysis of ,chile saltpeter by the direct method a variation of #j4be per cent in the content of nitrogen is allowed from the dealers' guaranty4 ,this would allow a total variation in the content of sodium nitrate of #a4eb per cent4 ,dealers and shippers have always been accustomed to estimate the quantity of sodium nitrate in a sample by difference2 i4 e41 by estimating the constituents not sodium nitrate and subtracting the sum of the results from #ajj4 ,chile saltpeter usually contains sodium nitrate1 water1 insoluble ferruginous matters1 sodium chlorid1 sodium sulfate1 magnesium chlorid1 sodium iodate1 calcium sulfate and sometimes small quantities of potassium nitrate4 ,when the total sodium nitrate is to be estimated by difference the following procedure1 arranged by ,crispo1#ahb may be followed3 ,water4--,dry ten grams of the finely powdered sample to constant weight at #aej-afj4 ,chlorin4--,the residue1 after drying1 is dissolved and the volume made up to one-fourth liter with water and the chlorin determined in one-fifth thereof and calculated as sodium chlorid4 ,insoluble4--,twenty grams are treated with water until all soluble matter has disappeared1 filtered on a tared gooch1 and the filtrate dried to constant weight4 ,sulfuric ,acid4--,the sulfuric acid is precipitated by barium chlorid in the slightly acid filtrate from the insoluble matter4 ,the acidity is produced by a few drops of nitric acid4 ,the rest of the process is conducted in the usual way4 ,magnesia4--,this is precipitated by ammonium sodium phosphate1 filtered1 ignited1 and weighed as pyrophosphate4 ,the magnesium is then calculated as chlorid4 ,magnesia is rarely found in excess of one-fourth per cent4 ,when this amount is not exceeded the estimation of it may be neglected without any great error4 ,as has already been said the chlorin is all calculated as sodium chlorid4 ,if a part of it be combined with one-fourth per cent of magnesia it would represent #j4ei per cent of magnesium chlorid instead of #j4gc per cent sodium chlorid4 ,in omitting the estimation of the magnesia therefore the importer is only damaged to the extent of #j4ad per cent of sodium nitrate4 ,sodium ,iodate4--,this body1 present only in small quantities1 may also be neglected4 ,in case the content of this body should reach one-fourth per cent the estimation of chlorin by titration using potassium chromate as indicator is impracticable4 ,such an instance1 however1 is rarely known4 ,approximate ,results4--,when the determinations outlined above have been carefully made it is claimed that the result obtained by subtraction from #ajj will not vary more than from two-tenths to three-tenths per cent from the true content of sodium nitrate4 ,the method1 however1 cannot be considered strictly scientific and is much more tedious and chronophagous than the direct determination4 ,in the direct determination1 however1 the analyst must assure himself that potassium is present in only appreciable quantities otherwise the per cent of sodium nitrate will be too low4 ,the presence of potassium nitrate is a detriment in this respect only2 viz41 that it contains a less percentage of nitrogen than the corresponding sodium salt4 ,as a fertilizer1 the value of ,chile saltpeter may be increased by its content of potassium4 #bah4 ,the ,application of ,chile ,saltpeter to the ,soil4--,the analyst is often asked to determine the desirability of the use of sodium nitrate as a fertilizer and the methods and times of applying it4 ,these are questions which are scarcely germane to the purpose of this work but which1 nevertheless1 for the sake of convenience may be briefly discussed4 ,in the first place it may be said that the data of a chance chemical analysis will not afford a sufficiently broad basis for an answer4 ,a given soil may be very rich in nitrogen as revealed by chemical analysis1 and yet poor in an available supply4 ,this is frequently the case with vegetable soils1 containing1 as they do1 large quantities of nitrogen but holding it in practically an inert state4 ,i have found such soils very rich in nitrogen1 yet almost entirely devoid of nitrifying organisms4 ,it is necessary therefore in reaching a judgment on this subject from analytical data to consider the different states in which the nitrogen may exist in a soil and above all the nitrifying power of the soil if the nitrogen be chiefly present in an organic state4 ,culture solutions should therefore be seeded with samples of the soil under examination and the beginning and rapidity of the nitrification carefully noted4 ,in conjunction with this the nitrogen present in the soil in a nitric or ammoniacal form should be accurately determined4 ,these determinations should be made according to the directions given in the first volume1 pp4 #ddh-edh4 ,for the determination of nitrifying power we prefer the following method3 #bai4 ,taking ,samples of ,soil in ,sterilized ,tubes4--,brass tubes are prepared twenty centimeters in length and one and a half in diameter4 ,one end is ground to a beveled edge and compressed in a mold so as to make the cutting edge slightly smaller in diameter than the internal diameter of the tube4 ,it is then ground or filed until smooth and sharp4 ,the blunt end of the tube is stoppered loosely with cotton and it is then sterilized by heating for an hour to #aej4 ,rubber caps are provided and each one has placed at the bottom a rubber ball to prevent the rubber from being cut by the edges of the brass tube4 ,the caps should be of two distinct colors4 ,half of the rubber caps are sterilized by being boiled for an hour in water for three successive days4 ,the caps cannot be heated to #aej dry heat with safety4 ,on removing the brass tube from the sterilizing oven as soon as it is cool enough to handle1 a sterilized rubber cap is slipped over its cutting end4 ,an unsterilized cap is then slipped over the other end containing the cotton plug4 ,inasmuch as the cotton plug is never removed it is not necessary to sterilize the cap covering it4 ,large numbers of the tubes can thus be prepared for use and they can be safely transmitted to a distance by express or mail4 ,for convenience1 each tube is encased in a small cloth bag1 which is tied with a cord carrying a tag on which the necessary data can be recorded at the time of taking the sample4 ,the tubes and their rubber caps thus carefully sterilized should not be removed from their cloth envelopes until the moment of taking each sample4 ,after the sample has been taken and the cap replaced on the tube the latter should be immediately enclosed in the cloth sack and labeled with one of the tags therewith enclosed4 ,the sample should be taken in two kinds of soil1 in one instance in a cultivated soil1 which is most characteristic of the locality1 and in the second place a virgin soil of the same type4 ,the virgin soil may be either soil which has been covered with grass or in forest4 ,the spots at which the samples are to be taken having been previously selected1 the tags for each tube should be prepared beforehand so as to avoid delay at the time of sampling4 ,a pit with straight walls should be dug1 the sides of which are at least two feet wide and even three feet would be better4 ,the pit should be about forty-two inches deep4 ,one of the sides having been made perfectly smooth and without allowing the loose fragments from the top to fall down and adhere to the walls below1 the spots at which the samples are to be taken should be marked with a tape line at the following points2 viz41 three1 fifteen1 twenty-seven1 and thirty-nine inches1 respectively1 below the surface4 ,beginning at the bottom point1 carefully scrape off the surface of the wall over an area slightly larger than that of the end of the sample tube by means of a spatula1 which1 just previous to use1 has been held for a moment or two in the flame of an alcohol or other convenient lamp4 ,the sample tube having been removed from its sack1 it will be noted that the end covered with black rubber is the one which is to be held in the hand1 and this black rubber cap should be first removed being careful not to extract the plug of sterilized cotton which closes the end of the tube4 ,holding the tube firmly by the end1 the fingers extending only about two inches from the end1 remove the light-colored cap and push the tube with a turning motion into the side of the pit at the point where the surface has been removed with the sterilized spatula4 ,when this is properly done the tube will be filled with a cylinder of soil equal to the length of the part of the tube penetrating the wall of the pit4 ,the tube is then withdrawn1 the light rubber cap first replaced1 and then the black one4 ,the light rubber cap should be held in the hand during the process in such a way that no dust or particles of soil are permitted to contaminate its inner walls4 ,for this purpose the open end of the cap should be held downward4 ,for the same reason after the removal of the light rubber cap the brass tube should be carefully preserved from dust or fragments1 the open end1 that is the cutting end1 being held downward until ready for use4 ,after one tube has been filled1 capped1 replaced in the sack and labeled1 the spatula should be again sterilized and samples taken in regular order until the top one is finished4 #bbj4 ,directions for ,taking ,bulk ,samples4--,from the sides of the pit described above1 bulk samples should be taken as follows3 ,by means of a spade the soil should be removed from the four sides to the depth of six or nine inches or until the change of color between the soil and subsoil is noted2 in all enough to make about #aej pounds of the air-dried soil4 ,in the same way take a sample of the subsoil to the depth of nine additional inches4 ,remove all stones1 large pebbles1 sticks1 roots1 etc41 and spread the samples in a sheltered place where they can be air-dried as rapidly as possible4 ,the bulk samples should be taken both from the cultivated and virgin soils4 ,in selecting the cultivated soil1 preference should be given to those soils which have not been fertilized within a few years4 ,if recent fertilization have been practiced the character and amount of it should be noted4 #bba4 ,the ,nitrifiable ,solution4--,the solution to test the nitrifying power of the samples collected as above described is conveniently made as follows3 ,potassium phosphate1 one gram per liter4 ,magnesium sulfate1 half a gram per liter4 ,calcium chlorid1 a trace4 ,ammonium sulfate1 #bjj milligrams of nitrogen per liter4 ,calcium carbonate1 in excess4 ,one liter of the above solution is enough for ten samples1 each of #ajj cubic centimeters4 ,this quantity is placed in an erlenmeyer1 which is stoppered with cotton and sterilized by being kept at #ajj for an hour on three successive days4 ,the erlenmeyer should be sterilized beforehand by heating for an hour at #aej4 ,the freshly precipitated and washed calcium carbonate should be sterilized separately and added to each erlenmeyer at the time of seeding4 ,enough should always be used to be in excess of the nitrous and nitric acids found4 ,the seeding is accomplished by filling a sterilized spoon which holds approximately half a gram of the soil1 from the contents of one of the brass tubes1 lifting the plug in the erlenmeyer and transferring quickly to the flask4 ,this should be done in a perfectly still room1 preferably as high above the ground as possible and in a place free from dust and under cover4 ,the cotton plug being replaced the erlenmeyer is shaken until the sample of soil added is thoroughly disintegrated and intimately mixed with its contents4 ,with care and experience the seeding is easily accomplished without danger of accidental contamination4 ,at the end of each period of five days the beginning and progress of nitrification should be determined by some of the methods described in volume first4 ,either the ammonia can be determined by nesslerizing or the nitrous and nitric acids estimated4 ,for nitrous acid we prefer the method described in volume first1 paragraph #ejd1 and for nitric the one in same volume paragraphs #dig and #dih4 ,by supplementing the analysis of a soil by the above described experiments in nitrification the analyst will be able to judge with sufficient accuracy of its needs for nitric nitrogen4 #bbb4 ,quantity of ,chile ,saltpeter to be ,applied4--,the quantities of ,chile saltpeter which should be applied per acre vary with so many conditions as to make any definite statement impossible4 ,on account of the great solubility of this salt no more should be used than is necessary for the nutrition of the crop4 ,for each #ajj pounds used1 from fourteen to fifteen pounds of nitrogen will be added to the soil4 ,field crops1 as a rule1 will require less of the salt than garden crops4 ,there is an economic limit to the application which should not be passed4 ,as a rule #bej pounds per acre will prove to be a maximum dressing4 ,the character of the crop must also be considered4 ,different amounts are required for sugar beets1 tobacco1 wheat1 and other standard crops4 ,it is rarely the case that a crop demands a dressing of ,chile saltpeter alone4 ,it will give the best effects1 as a rule1 when applied with phosphoric acid or potash4 ,but this is a branch of the subject which cannot be entered into at greater length in this manual4 ,the reader is referred to ,stutzer's work on ,chile saltpeter for further information4#ahc #bbc4 ,consumption of ,chile ,saltpeter4--,the entire consumption of sodium nitrate for manurial purposes in the whole world for #ahid was #iib1aej metric tons1 valued at #da1jjj1jjj4 ,for the several countries using it the consumption was distributed as follows3 ,germany #cig1bjj tons4 ,france #ahg1ajj 8 ,england #aag1jjj 8 ,belgium #abc1jjj 8 ,united ,states #ajj1jjj 8 ,holland #ef1gjj 8 ,italy and ,spain #e1bjj 8 ,other countries #e1iej 8 ------- ,total #iib1aej 8 ,the above figures represent the actual commerce of each country in ,chile saltpeter1 and may not give the exact consumption4#ahd ,for instance1 ,germany exports sodium nitrate to ,russia and ,austria1 but it imports this salt from ,holland and ,belgium4 ,belgium imports from ,france1 but its exportation is greater than its importations from that country1 so that its actual consumption on the farm probably falls considerably below that given on the table4 ,holland also exports larger quantities than are imported from neighboring states4 ,the exports from ,england are inconsiderable compared with the quantities received1 amounting only to about #e1jjj tons a year1 while the exportations from ,france reach nearly #aj1jjj tons4 ,sodium nitrate has a moderate value at the factories where it is prepared for shipment in ,chile4 ,its chief value at the ports where it is delivered for consumption comes from freights and profits of the syndicate4 ,the factories1 where it is prepared for the market1 are at or near the deposits1 and the freights thence to the sea coast are very high4 ,the rail roads which have been constructed to the high plateaux which contain the deposits1 have been built at a very great cost1 and the freights charged are correspondingly high4 ,there is also a tax of #a4bj levied on each ton exported4 ,deducting all costs of transportation and export duties the actual value of sodium nitrate at the factory1 ready for shipment1 is about sixteen dollars in gold a ton4 ,,authorities ,,cited ,,in ,,part ,,second4 #abe ,american ,chemical ,journal1 ,vol4 #ac1 ,no4 #g4 #abf ,atwater3 ,report of the ,u4 ,s4 ,commissioner of ,fish and ,fisheries1 #ahhh1 pp4 #fgi-hfh4 #abg ,american ,naturalist1 ,vol4 #ad1 p4 #dgc4 #abh ,wiley3 ,retiring ,address as ,president of ,american ,chemical ,society1 ,baltimore ,meeting1 ,dec4 #ahic1 ,journal of the ,american ,chemical ,society1 ,vol4 #af1 pp4 #ag-bj4 #abi ,vid4 op4 et4 loc4 cit4 supra4 #acj ,vid4 op4 et4 loc4 cit4 #d4 #aca ,vid4 op4 et4 loc4 cit4 #d4 #acb ,vid4 op4 et4 loc4 cit4 #d4 #acc ,bulletin ,no4 #dc1 p4 #cdc 7to paragraph #aef74 #acd ,american ,chemical ,journal1 ,vol4 #b1 pp4 #bg1 et seq4 #ace ,vid4 op4 et4 loc4 cit4 supra4 #acf ,weather ,bureau3 ,barometers and ,measurements of ,atmospheric ,pressures4 #acg ,physikalisch-,chemische ,tabellen ,landolt und ,brnstein1 ,s4 #cb4 #ach ,battle and ,dancy3 ,conversion ,tables1 p4 #cd4 #aci ,bulletin ,no4 #dc1 p4 #cdh 7to paragraph #afi74 #adj ,guide pour le dosage de l',azote ,no4 #c1 p4 #h4 #ada ,zeitschrift fr analytische ,chemie1 ,band #bc1 ,s4 #eeg4 #adb ,chemiker ,zeitung1 ,band #h1 ,s4 #agdg4 #adc ,journal of the ,chemical ,society1 ,transactions1 #ahha1 p4 #hg4 #add ,bulletin ,no4 #af1 p4 #ea4 #ade ,bulletin ,no4 #bh1 p4 #aic 7to paragraph #age74 #adf ,journal ,society of ,chemical ,industry1 ,vol4 #b1 p4 #ba4 #adg ,bulletin de l',association des ,chimistes de ,sucrrie1 ,tome #i1 p4 #eih4 7bis p4 #aib7 ,journal ,chemical ,society2 ,transactions1 ,vol4 #ba1 p4 #afa4 #adh ,zeitschrift fr analytische ,chemie1 ,band #bb1 ,s4 #cff4 #adi ,vid4 op4 cit4 supra1 pp4 #cgj1 et seq4 #aej ,vid4 op4 cit41 #bd4 ,band #bd1 ,s4 #dee4 #aea ,chemisches ,centralblatt1 #ahhf1 ,s4 #afe4 #aeb ,nederlandsche ,staatscourant1 ,jan4 #aa1 #ahic4 #aec ,die ,agricultur-,chemische ,versuchs-,station1 ,halle a_/,s41 ,s4 #cd4 7bis4 p4 #bjd7 ,bulletin ,no4 #dc1 p4 #cde4 #aed ,bulletin ,no4 #ca1 #adb4 #aee ,fresenius1 quantitative ,analyse1 #fth ,auflage1 ,s4 #gca4 #aef ,zeitschrift fr ,analytische ,chemie1 ,band #bd1 ,s4 #dee4 #aeg ,vid4 op4 cit4 supra1 ,band #be1 ,s4 #adi4 #aeh ,archive der ,pharmacie #c1 ,band #bc1 ,s4 #agg4 #aei ,chemisches ,centralblatt1 #ahhf1 ,s4 #cge4 #afj ,vid4 op4 cit4 supra1 ,s4 #afa4 #afa ,vid4 op4 cit4 #ce1 ,s4 #dcc4 #afb ,vid4 op4 et4 loc4 cit4 #bh4 #afc ,vid4 op4 cit4 #bi1 ,s4 #dd4 #afd ,bulletin ,no4 #af1 p4 #ea4 #afe ,zeitschrift fr analytische ,chemie1 ,band #bh1 ,s4 #ahh4 #aff ,bulletin ,no4 #ce1 p4 #fh4 #afg ,bulletin ,no4 #ce1 p4 #bjb4 #afh ,bulletin ,no4 #aab1 ,connecticut ,agricultural ,experiment ,station1 and ,bulletin ,no4 #ce1 p4 #if4 #afi ,guide pour le dosage de l',azote1 p4 #ad4 #agj ,revue de ,chimie ,analytique ,applique1 ,tome #a1 p4 #ea4 #aga ,chemiker ,zeitung1 ,band #d1 ,s4 #cfj4 #agb ,bulletin ,no4 #dc1 p4 #cfa4 #agc ,bulletin de la ,socit ,chimique1 #ahij1 p4 #cbd4 #agd ,bulletin ,no4 #ce1 p4 #hh4 #age ,die ,agricultur-,chemische ,versuchs-,station1 ,halle a_/,s41 ,s4 #ej4 #agf ,vid41 ,vol4 #a1 p4 #eci4 #agg ,berichte der deutschen chemischen ,gesellschaft1 ,band #bg1 ,s4 #afcc4 #agh ,vid4 op4 et4 loc4 cit4 supra4 #agi ,vid4 op4 cit4 #ea1 ,s4 #dh4 #ahj ,zeitschrift fr analytische ,chemie1 ,band #cd1 ,s4 #bf4 #aha ,vid4 op4 cit4 supra1 ,band #cb1 ,s4 #eec4 #ahb ,l',engrais1 ,tome #i1 p4 #hgg4 #ahc ,der ,chile ,saltpeter2 ,seine ,bedeutung und ,anwendung als ,dngemittel4 #ahd ,l',engrais1 #e ,avril1 #ahie1 p4 #cbd4 ,,part ,,third4 ,,potash ,,in ,,fertilizing ,,materials ,,and ,,fertilizers4 #bbd4 ,introduction4--,the potash present in unfertilized soils has been derived from the decay of rocks containing potash minerals4 ,among these potash producers feldspars are perhaps the most important4 ,for a discussion of the nature of their decomposition and the causes producing it the first part of volume first may be consulted4 ,potash is quite as extensively distributed as phosphoric acid and no true soils are without it in some proportion4 ,its presence is necessary to plant growth and it forms1 in combination with organic and mineral acids1 an essential part of the vegetable organism1 existing in exceptionally rich quantities in the seeds4 ,it is possible that potash salts1 such as the chlorid1 sulfate1 and phosphate may be assimilated as such1 but1 as with other compounds1 we must not deny to the plant the remarkable faculty of being able to decompose its most stable salts and to form from the fragments thus produced entirely new compounds4 ,this is certainly true of the potash compounds existing in plants in combination with organic acids4 ,the potash which is assimilated by plants exists in the soil chiefly in a mineral state1 and that added as fertilizer is chiefly in the same condition4 ,that part of the potash in a soil arising directly from the decomposition of vegetable matters may exist partly in organic combination1 but this portion1 in comparison with the total quantity absorbed by the plant1 is insignificant4 ,it is then safe to assume that at least a considerable part of the potash absorbed by the plant is decomposed from its original form of combination by the vegetable biochemical forces1 and is finally incorporated in the plant tissues in forms determined by the same powerful forces of vegetable metabolism4 ,the analyst is not often called upon to investigate the forms in which the potash exists in plants1 when engaged in investigation of fertilizers4 ,it is chiefly found in combination with organic and phosphoric acids1 and on ignition will appear as phosphate or carbonate in the ash4 #bbe4 ,forms in which ,potash is ,found in ,fertilizers4--,the chief natural sources of potash used in fertilizer fabrication are3 ,first1 organic compounds1 such as desiccated mineral matters1 tobacco waste1 cottonseed hulls1 etc42 second1 the ash derived from burning terrestrial plants of all kinds2 third1 the natural mineral deposits1 such as ,stassfurt salts4 ,all of these forms of potash may be found in mixed fertilizers4 ,while the final methods of analyses are the same in all cases the preliminary treatment is very different1 being adapted to the nature of the sample4 ,for analytical purposes1 it is highly important that the potash be brought into a soluble mineral form1 and that any organic matters which the sample contains be destroyed4 ,if the sample be already of a mineral nature1 it may still be mixed with other organic matter and then it requires treatment as above1 for it is not safe always to rely solely on the solubility of the potash mineral1 and the solution1 moreover1 in such cases1 is likely to contain organic matter4 ,in some ,states1 only that portion of the potash soluble in water is allowed to be considered in official fertilizer work4 ,in these cases it is evident that the organic matter present should not be destroyed in the original sample1 but only in the aqueous solution4 ,since1 however1 the potash occluded in organic matter becomes constantly available as the process of decay goes on1 it is not just to exclude it from the available supply4 ,it may not be so immediately available as when in a soluble mineral state1 but it is not long before it becomes valuable4 ,experience has shown1 moreover1 that phosphorus1 nitrogen1 and potash are all more valuable finally when applied to the soil in an organic form4 ,this fact is a corroboration of the theory already advanced that all mineral compound bodies are probably decomposed before they enter as component parts into the tissues of the vegetable organism4 ,it is highly probable1 therefore1 that the potash existing in organic compounds1 finely divided and easily decomposed1 is of equal1 if not greater value to plant life than that already in a soluble mineral state4 ,the organic matter1 when present1 is destroyed1 either by ignition at a low temperature1 or by moist combustion with an oxidizing agent before the potash is precipitated4 ,,organic ,,sources ,,of ,,potash4 #bbf4 ,tobacco ,stems and ,waste4--,until within a few years tobacco stems and other waste from factories1 were treated as a nuisance in this country1 and burned or dumped into streams4 ,by burning and saving the ash the potash contained in the stems and waste would be recovered in a form suitable for field use4 ,the nitrogen1 however1 contained in these waste materials1 both in the form of nicotin and of albuminoids would be lost4 ,ignition of this waste1 therefore1 should not be practiced4 ,it should be prepared for use by grinding to a fine powder4 ,applied to the soil in this condition the powder may be useful as an insecticide as well as a fertilizer4 ,tobacco stems contain from twelve to twenty-seven per cent of moisture1 and from twelve to twenty per cent of ash4 ,the composition of the stems from two celebrated tobacco growing regions is subjoined3#ahe ,kentucky stems4 ,connecticut stems4 ,moisture #bf4gj per cent4 #ac4dg per cent4 ,organic and volatile #fj4ah 8 8 #gj4he 8 8 ,ash #ac4ab 8 8 #ae4fh 8 8 ,the ash calculated to the original substance had the following composition3 ,kentucky stems4 ,connecticut stems4 ,phosphoric acid #j4fg per cent4 #j4ec per cent4 ,potash #h4jc 8 8 #f4da 8 8 ,it is thus seen that about half the ash of tobacco stems is composed of potash4 ,the stalks of the tobacco have almost the same composition as the stems1 but the percentage of ash is not quite so great4 ,in three samples analyzed at the ,connecticut station the percentages of ash found in the water-free substance were #f4fd1 #g4jj1 and #g4df respectively4 ,the pure ash of the stalks was found to have the following composition3#ahf ,description of samples4 ,constituents ,cut ,aug4 #bb4 ,cut ,sept4 #ag4 ,silica #j4hb per cent4 #j4eg per cent4 ,iron and aluminum oxids #a4ch 8 8 #a4ch 8 8 ,lime #ad4ja 8 8 #af4eh 8 8 ,magnesia #f4fd 8 8 #g4cf 8 8 ,potash #ef4cd 8 8 #ed4df 8 8 ,soda #a4bh 8 8 #a4af 8 8 ,sulfuric acid #h4jf 8 8 #f4ge 8 8 ,phosphoric acid #f4cg 8 8 #f4bg 8 8 ,chlorin #f4ee 8 8 #g4je 8 8 ------ ------ #aja4de 8 8 #aja4eh 8 8 ,deduct oxygen chlorin #a4de 8 8 #a4eh 8 8 ------ ------ #ajj4jj 8 8 #ajj4jj 8 8 ,the leaves of the tobacco contain more ash than the stalks or stems1 but the percentage of potash therein is less4 ,in eighteen samples analyzed at the ,colorado station the percentages of moisture in the leaf varied from #f4jh to #bh4jj1 and those of ash from #bb4fj to #bh4jj4ahg ,the percentages of potash in the ash varied from #ae4bj to #bf4cj4 ,in these data the carbon dioxid1 sand1 etc41 are included1 while in those quoted from the ,connecticut station they were excluded4 #bbg4 ,cottonseed ,hulls and ,meal4--,a considerable quantity of potash is added to the soil in cottonseed meal and hulls4 ,the practice of burning the hulls cannot be recommended1 although it is frequently practiced1 for the incineration does not increase the quantities of phosphoric acid and potash1 while it destroys the availability of the nitrogen4 ,nevertheless the analyst will often have to deal with samples of the raw materials above mentioned1 as well as with the ash of the hulls1 in which the potash can be determined by some one of the standard methods to be described4 ,in general it is found that the hulls of seeds and the bark and leaves of plants have a greater percentage of ash than the interior portions4 ,in the case of cottonseed however1 an exception is to be noted4 ,the cottonseed meal in the air-dried state has about seven per cent of ash1 while the hulls have only about three4 ,when it is remembered1 however1 that the greater part of the oil has been removed from the meal it will be seen that in the whole seed in the fresh state the discrepancy is not so marked4 ,in the crude ash of the hulls the percentage of potash varies generally from twenty to twenty-five per cent1 but in numerous cases these limits are exceeded4 ,in twelve samples of cottonseed hull ashes examined by the ,connecticut station the mean percentage of potash in the crude sample was #bb4dg1 and the extremes #ae4eg and #cj4bd per cent respectively4#ahh ,in determining the value of the ash per ton the content of phosphoric acid must also be taken into account4 ,cottonseed meal contains about #a4ge per cent of potash4 ,since the mean percentage of ash in the meal is seven1 the mean content of potash in the crude ash is about twenty-five4 #bbh4 ,wood ,ashes4--,unleached wood ashes furnish an important quantity of potash fertilizer4 ,the composition of the ash of woods is extremely variable4 ,not only do different varieties of trees have varying quantities of ash1 but in the same variety the bark and twigs will give an ash quite different in quantity and composition from that furnished by the wood itself4 ,in general the hard woods1 such as hickory1 oak1 and maple1 furnish a quality of ash superior for fertilizing purposes to that afforded by the soft woods1 such as the pine and tulip trees4 ,the character of the unleached wood ashes found in the trade is indicated by the subjoined analyses4 ,the first table contains the mean1 maximum and minimum results of the analyses of ninety-seven samples by ,goessmann4#ahi ,mean composition of wood ashes4 ,means4 ,maxima4 ,minima4 ,potash #e4e #aj4b #b4e ,phosphoric acid #a4i #d4j #j4c ,lime #cd4c #ej4i #ah4j ,magnesia #c4e #g4e #b4c ,insoluble #ab4i #bg4i #b4a ,moisture #ab4j #bh4f #j4g ,carbon dioxid and undetermined #bi4i ,in sixteen analyses made at the ,connecticut station the data obtained are given below3#aij ,means4 ,maxima4 ,minima4 ,potash #e4c #g4g #d4j ,phosphoric acid #a4d #a4h #j4i ,in fifteen analyses of ashes from domestic wood-fires in ,new ,england stoves1 the following mean percentages of potash and phosphoric acid were found3 ,potash #i4fc ,phosphoric acid #b4cb ,in leaching1 ashes lose chiefly the potassium carbonate and phosphate which they contain4 ,leached and unleached ,canada ashes have the following composition3 ,unleached4 ,leached4 ,insoluble #ac4j per cent4 #ac4j per cent4 ,moisture #ab4j 8 8 #cj4j 8 8 ,calcium carbonate and hydroxid #fa4j 8 8 #ea4j 8 8 ,potassium carbonate #e4e 8 8 #a4a 8 8 ,phosphoric acid #a4i 8 8 #a4d 8 8 ,undetermined #f4f 8 8 #c4e 8 8 ,in the wood ashes of commerce therefore1 it is evident that the proportion of the potash to the lime is relatively low4 ,the number of parts by weight of the chief ingredients of the ash in ten thousand pounds of woods of different kinds is given in the table below together with the percentage composition of the pure ash1 that is the crude ash deprived of carbon and carbon dioxid4 ,,pounds ,,of ,,the ,,ingredients ,,named ,,in ,,ten ,,thousand ,,pounds ,,of ,,wood4 ---------------------------------------- ------------------------ ,dogwood4 ,sycamore4 ,post oak4 ,ash4 ,cornus ,platanus ,q4 ,f4 florida4occidentalis4obtusiloba4,america na4 ---------------------------------------- ------------------------ ,potash #i4jb #ah4jf #af4he #ad4id ,phosphoric acid #e4gb #i4ee #f4if #a4ae ,lime #f4da #bd4gc #ce4fa #g4fj ,magnesia #ad4fg 4#di #e4bh 4#aj ---------------------------------------- ----------------------- ---------------------------------------- ----------------- ,red ,hickory4 ,white ,magnolia4 oak4 ,carya oak4 ,m4 ,q4 tomentosa4 ,q4 grandiflora4 rubra4 alba4 ---------------------------------------- ---------------- ,potash #ac4ie #ac4hj #aj4fj #g4ac ,phosphoric acid #e4ih #e4hc #b4di #c4ai ,lime #bg4dj #ah4dj #g4he #ad4ba ,magnesia #c4je #d4hf 4#ij #b4id ---------------------------------------- ---------------- ---------------------------------------- ------------------------- ,georgia ,yellow ,black ,chestnut4 ,old field pine4 pine4 pine4 ,castanea pine4 ,p4 ,p4 ,picea vesca or ,p4 mitis4 palustris4mitis4nigra4sativa4 ---------------------------------------- ------------------------ ,potash #e4ja #d4ed #c4jb #b4ij 4#gi ,phosphoric acid #a4bd 4#if 4#ib #a4ji 4#gc ,lime #ah4jd #ae4af #ab4df #g4ic #ab4ab ,magnesia #b4jc 4#gd 4#aj 4#cd #a4ag ---------------------------------------- ------------------------ ,,the ,,pure ,,ashes ,,of ,,the ,,woods ,,contain ,,the ,,following ,,per ,,cents ,,of ,,the ,,ingredient ,,named4 ---------------------------------------- ------------------------ ,dogwood4 ,sycamore4 ,post oak4 ,ash4 ,cornus ,platanus ,q4 ,f4 florida4occidentalis4obtusiloba4,america na4 ---------------------------------------- ------------------------ ,potash #bh4jd #bc4ag #ba4ib #df4jd ,phosphoric acid #h4ea #ab4bc #i4jj #c4eh ,lime #ch4ic #ca4fb #df4ci #bc4eg ,magnesia #f4hj 4#fb #f4hh 4#fj ---------------------------------------- ----------------------- ---------------------------------------- ----------------- ,red ,hickory4 ,white ,magnolia4 oak4 ,carya oak4 ,m4 ,q4 tomentosa4 ,q4 grandiflora4 rubra4 alba4 ---------------------------------------- ---------------- ,potash #bd4ff #bh4fj #db4af #ai4ed ,phosphoric acid #aj4ee #aa4ig #i4dh #h4ge ,lime #dh4bf #cg4id #bi4he #ch4id ,magnesia #e4ch #aj4jd #c4dc #h4je ---------------------------------------- ---------------- ---------------------------------------- ------------------------- ,georgia ,yellow ,black ,chestnut4 ,old field pine4 pine4 pine4 ,castanea pine4 ,p4 ,p4 ,picea vesca or ,p4 mitis4 palustris4mitis4nigra4sativa4 ---------------------------------------- ------------------------ ,potash #ae4ce #ai4gj #ad4cj #ah4aj #c4he ,phosphoric acid #c4hb #d4ah #d4cc #f4gf #d4aa ,lime #ee4bd #fe4ec #eh4ih #di4ah #fg4gc ,magnesia #f4be #c4bj 4#ej #b4aa #f4ed ---------------------------------------- ------------------------ #bbi4 ,fertilizing ,value of ,ashes4--,primarily1 the fertilizing value of wood-ashes depends on the quantity of plant food which they contain4 ,with the exception of potash and phosphoric acid1 however1 the constituents of wood-ashes have little1 if any1 commercial value4 ,the beneficial effects following the application of ashes1 however1 are greater than would be produced by the same quantities of matter added in a purely manurial state4 ,the organic origin of these materials in the ash has caused them to be presented to the plant in a form peculiarly suited for absorption4 ,land treated generally with wood-ashes becomes more amenable to culture1 is readily kept in good tilth1 and thus retains moisture in dry seasons and permits of easy drainage in wet4 ,these effects are probably due to the lime content of the ash1 a property moreover favorable to nitrification and adapted to correcting acidity4 ,injurious iron salts1 which are sometimes found in wet and sour lands1 are precipitated by the ash and rendered innocuous or even beneficial4 ,a good wood-ash fertilizer therefore is worth more than would be indicated by its commercial value calculated in the usual way4 #bcj4 ,molasses from ,sugar-,beets4--,the residual molasses resulting after the extraction of all the crystallizable sugar in beet-sugar manufacture is very rich in potash4 ,the molasses contains from ten to fifteen per cent of ash4 ,the composition of the ash varies greatly in the content of potash as well as of the other constituents4#aia ,the content of potassium carbonate varies from twenty-two to fifty-five per cent and1 in addition to this1 some potassium sulfate and chlorid are usually present4 ,the following figures give the composition of a good quality of beet-molasses ash3 ,potassium carbonate #de4cj per cent ,sodium 8 #ac4hf 8 ,potassium chlorid #bb4dj 8 8 sulfate #h4jj 8 ,silica1 lime1 alumina1 water1 phosphoric acid1 and undetermined #ae4hb 8 ,thus1 in #ajj parts of such an ash over three-quarters are potash salts4 ,the molasses may be applied directly to the soil or diluted and sprayed over the fields4 #bca4 ,residue of ,wineries4--,the pomace of grapes after being pressed or fermented for wine production contains considerable quantities of potash as crude argol or acid potassium tartrate4 ,this material can be applied directly to the soil or first burned1 when its potash will be secured in the form of carbonate4 ,the use of the winery refuse for fertilizing purposes has not assumed any commercial importance in this country4 #bcb4 ,destruction of ,organic ,matter by ,direct ,ignition4--,the simplest and most direct method for destroying organic matter is by direct ignition4 ,the incineration may be conducted in the open air or in a muffle and the temperature should be as low as possible4 ,in no case should a low red heat be exceeded4 ,by reason of the moderate draft produced in a muffle and the more even heat which can be maintained this method of burning is to be preferred4 ,with the exercise of due care1 however1 excellent results can be obtained in an open dish or one partly closed with a lid4 ,at first1 with many samples1 the organic matter will burn of its own accord after it is once ignited1 and during this combustion the lamp should be withdrawn4 ,the ignition in most cases should be continued in a platinum dish but should the sample contain any reducible metal capable of injuring the platinum a porcelain vessel should be used4 ,the lamp should give a diffused flame to avoid overheating of any portions of the dish and to secure more uniform combustion4 ,in using a muffle the heat employed should be only great enough to secure combustion and the draft should be so regulated as to avoid loss due to the mechanical deportation of the ash particles4 #bcc4 ,ignition with ,sulfuric ,acid4--,the favorable action of sulfuric acid in securing a perfect incineration may also be utilized in the preparation of samples containing organic matter for potash determinations4 ,in this case the bases which by direct ignition would be secured as carbonates are obtained as sulfates4 ,in the method adopted by the official chemists it is directed to saturate the sample with sulfuric acid and to ignite in a muffle until all organic matter is destroyed4#aib ,afterwards1 when cool the ash is moistened with a little hydrochloric acid and warmed1 whereby it is the more easily detached from the dish4 ,the potash is then determined by any one of the standard methods4 ,this method has several advantages over the direct ignition4 ,where any chlorids of the alkalies are present in the ash there is danger of loss of potash from volatilization4 ,this is avoided by the sulfate process4 ,moreover1 there is not so much danger in this method of occluding particles of carbon in the ash4 #bcd4 ,the ,destruction of ,organic ,matter by ,moist ,combustion4--,in the process of ignition to destroy organic matter or remove ammonium salts in the determination of potash1 there are often sources of error which may cause considerable loss4 ,this loss1 as has already been mentioned1 may arise from the volatilization of the potash salts or mechanically from spattering4 ,in order to avoid these causes of error de ,roode has used aqua regia both for the destruction of the ammonium salts and for the oxidation of the organic matter at least sufficiently to prevent any subsequent reduction of the platinum chlorid4#aic ,his method consists in boiling a sample of the fertilizer1 or an aliquot portion of a solution thereof with aqua regia4 ,the proposed method has not yet had a sufficient experimental demonstration to warrant its use1 but analysts may find it profitable to compare this process with the standard methods4 ,the organic matter may also be destroyed by combustion with sulfuric acid1 as in the kjeldahl method for nitrogen4 ,the residue1 however1 contains ammonium sulfate and a large excess of sulfuric acid1 and for both reasons would not be in a fit condition for the estimation of potash4 ,it is suggested that the organic matter might also be destroyed by boiling with strong hydrochloric acid1 to which from time to time1 small quantities of sodium chlorate free of potash is added4 ,subsequently the solution could be boiled with addition of a little nitric acid and the ammonium salts be removed4 ,,potash ,,in ,,mineral ,,deposits4 #bce4 ,occurrence and ,history4--,the generally accepted theory of the manner in which potash has been collected into deposits suited to use as a fertilizer has already been described4#aid ,the ,stassfurt deposits1 which have for many years been almost the sole source of potash in fertilizers1 were first known as mines of rock salt4 ,in #ahci1 having previously been acquired by the ,prussian treasury1 they were abandoned by reason of the more economical working of rock salt quarries in other localities4#aie ,it was determined thereafter to explore the extent of these mines by boring1 and a well was sunk to the depth of #bdf meters1 when the upper layer of the salt deposit was reached4 ,the boring was continued into the salt to a total depth of #eha meters without reaching the bottom4 ,the results of these experiments were totally unexpected4 ,instead of getting a brine saturated with common salt1 one was obtained containing large quantities of potassium and magnesium chlorids4#aif ,shafts were sunk in other places1 and with such favorable results1 that in #ahfb potash salts became a regular article of commerce from that locality4 ,at first these salts were regarded as troublesome impurities in the brine from which common salt was to be made1 but at this time the common salt has come to be regarded as the disturbing factor4 ,at the present time the entire product is controlled by a syndicate of nine large firms located at ,stassfurt and vicinity4 ,outside of the syndicate properties a shaft has been sunk at ,anderbeck1 7,halberstadt17 which1 however1 has produced only carnallit1 since kainit has not been found there4 ,also at ,sondershausen1 potash salts have been discovered and a shaft is now sinking there4 ,it is thus seen that the potash deposits extend over a wide area in ,germany1 and there is little fear of the deposits becoming exhausted in many centuries4 ,in this country no potash deposits of any commercial importance have been discovered2 but the geological conditions requisite to these formations have not been wanting1 and their future discovery is not improbable4 ,illustration3 ,,figure #ag4 ,,geological ,,relations ,,of ,,the ,,potash ,,deposits ,,near ,,stassfurt4 #bcf4 ,changes in ,potash ,salts in ,situ4--,the deposits of potash salts are not all found at the present in the same condition in which they were first deposited from the natural brines4 ,the layers of salt have been subjected to the usual upheavals and subsidences peculiar to geological history4 ,the layers of salt were thus tilted and the edges often brought to the surface4 ,here they were exposed to solution1 and the dissolved brine afterward separated its crystallizable salts in new combinations4 ,for instance1 kieserit and the potassium chlorid of the carnallit were first dissolved and there was left a salt compound chiefly of potassium and sodium chlorids1 sylvinit4 ,in some cases there was a mutual reaction between the magnesium sulfate and the potassium chlorid and the magnesium potassium sulfate1 schnit1 was thus produced4 ,this salt is also prepared at the mines artificially4 ,the most important of these secondary products however1 from the agricultural standpoint1 is kainit4 ,this salt arose by the bringing together of potassium sulfate1 magnesium sulfate1 and magnesium chlorid1 and was formed everywhere about the borders of the layers of carnallit wherever water could work upon them4 ,in quantity the kainit1 as might be supposed1 is far less than the carnallit1 the latter existing in immense deposits4 ,there is however quite enough of it to satisfy all the demands of agriculture for an indefinite time4 ,in fact for many purposes the carnallit can take the place of kainit without detriment to the growing crops4 ,the relative positions and quantities of the layers of mineral matters in the potash mines1 and the depth in meters at which they are found is shown in ,fig4 #ag4aig #bcg4 ,kainit4--,the most important of the natural salts of potash for fertilizing purposes is the mixture known as kainit4 ,it is composed in a pure state of a molecule each of potassium sulfate1 magnesium sulfate1 magnesium chlorid1 and water4 ,chemically it is represented by the symbols3 ,k,,so,mg,s,o,mg,cl,h,o4 ,its theoretical percentage of potash 7,k,o71 oxygen #af1 is #bc4b4 ,pure kainit1 however1 is never found in commerce4 ,it is mixed naturally as it comes from the mines with common salt1 potassium chlorid1 gypsum1 and other bodies4 ,the content of potash in the commercial salt is therefore only a little more than half that of the pure mineral4 ,in general it may be taken at #ab4e per cent1 of which more than one per cent is derived from the potassium chlorid present4 ,the following analysis given by ,maercker may be regarded as typical3#aih ,potassium sulfate #ba4c per cent ,magnesium 8 #ad4e 8 ,magnesium chlorid #ab4d 8 ,potassium 8 #b4j 8 ,sodium 8 #cd4f 8 ,calcium sulfate 7gypsum7 #a4g 8 ,water #ab4g 8 ,alumina #j4h 8 ,kainit occurs as a crystalline1 partly colorless1 partly yellow-red mass4 ,when ground1 in which state it is sent into commerce1 it forms a fine1 gray-colored mass containing many small yellow and red fragments4 ,it is not hygroscopic and if it become moist it is due to the excess of common salt which it contains4 ,according to ,maercker kainit was formerly regarded as a potassium magnesium sulfate4 ,but this conception does not even apply to the pure salt much less to that which comes from the mines4 ,if1 therefore1 the agronomist desire a fertilizer free from chlorin he would be deceived in choosing kainit which may sometimes contain nearly fifty per cent of its weight of chlorids4 ,where a fertilizer free of chlorin is desired1 as for instance1 in the culture of tobacco1 kainit cannot be considered4 ,in many other cases1 however1 the chlorin content of this body instead of being a detriment may prove positively advantageous1 the chlorids on account of their easy diffusibility through the soil serving to distribute the other ingredients4 ,by reason of the presence of common salt and magnesium chlorid the ground kainit delivered to commerce tends to harden into compact masses4 ,to prevent this in ,germany it is recommended to mix it with about two and a half per cent of fine-ground dry peat4 ,such a mixture is recommended in all cases where the freshly ground kainit is not to be immediately applied to the soil4 #bch4 ,carnallit4--,this mineral is a mixture of even molecules of potassium and magnesium chlorids crystallized with six molecules of water4 ,it is represented by the symbols ,k,cl,mg,cl#f;,h,o4 ,as it comes from the mines it contains small quantities of potassium and magnesium sulfates and small quantities of other accidental impurities4 ,existing as it does in immense quantities it has been extensively used for the manufacture of the commercial potassium chlorid 7muriate of potash74 ,for many purposes in agriculture1 for instance1 fertilizing tobacco fields1 it is not suited1 and it is less widely used as a fertilizer in general than its alteration product kainit4 ,its direct use as a fertilizer however is rapidly increasing since later experience has shown that chlorin compounds are capable of a far wider application in agriculture without danger of injury than was formerly supposed4 ,as it comes from the mines1 the ,stassfurt carnallit has the following composition3#aii ,potassium chlorid #ae4e per cent4 ,magnesium 8 #ba4e 8 8 ,magnesium sulfate #ab4a 8 8 ,sodium chlorid #bb4d 8 8 ,calcium sulfate #a4i 8 8 ,water #bf4a 8 8 ,undetermined #j4e 8 8 ,pure carnallit would have the following composition3 ,chlorin #ch4c per cent4 ,potassium #ad4j 8 8 ,magnesium #h4g 8 8 ,water #ci4j 8 8 ,equivalent to ,potassium chlorid #bf4h 8 8 ,magnesium 8 #cd4b 8 8 ,water #ci4j 8 8 ,the commercial article as taken from the mines1 as is seen above1 has less potash 7,k,o7 than kainit1 the mean content being about nine and nine-tenths per cent4 ,those proposing to use this body for fertilizing purposes should bear in mind that it contains less potash and more chlorin than kainit4 ,carnallit occurs in characteristic brown-red masses4 ,on account of its highly hygroscopic nature it should be kept as much as possible out of contact with moist air and should not be ground until immediately before using4 ,by reason of the greater bulk in proportion to its content of potash and its hygroscopic nature and consequent increased difficulty in handling1 the price per unit of potash in carnallit is less than in kainit4 ,in some localities small quantities of ammonium chlorid have been found with carnallit but not to exceed one-tenth per cent4 ,it has therefore no practical significance to the farmer but may be of interest to the analyst4 #bci4 ,polyhalit4--,polyhalit is a mineral occurring in ,stassfurt deposits and consisting of a mixture of potassium1 magnesium1 and calcium sulfates1 with a small proportion of crystal water4 ,this mineral1 on account of its being practically free of chlorin1 would be one especially desirable for use in those cases1 as in the culture of tobacco1 where chlorids are injurious4 ,unfortunately1 it does not occur in sufficient quantities to warrant the expectation of its ever being found in masses large enough to become a general article of commerce4 ,it is found only in pockets or seams among the other ,stassfurt deposits1 and there is no assurance given on finding one of these deposits of polyhalit that it will extend to any great distance4 ,the composition of the mineral is shown by the following formula3 ,k,,so,mg,s,o7,ca,s,o7,h,o4 ,its percentage composition is shown by the following numbers3 ,potassium sulfate #bh4ij per cent4 ,magnesium sulfate #ai4ic 8 8 ,calcium sulfate #de4ah 8 8 ,water #e4ii 8 8 ,the percentage of potash corresponding to the above formula is #ae4fb4 ,it therefore contains a considerable excess of potash over kainit1 and on account of its freedom from chlorids1 would be preferred for many purposes4 #bdj4 ,krugit4--,this mineral occurs associated with polyhalit and differs from it only in containing four molecules of calcium sulfate instead of two4 ,its formula is3 ,k,,so,mg,s,o7,ca,s,o7,h,o4 ,as it comes from the mines it is frequently mixed with a little common salt4 ,its mean percentage composition as it comes from the mines is given in the following numbers3 ,potassium sulfate #ah4fj per cent4 ,magnesium sulfate #ad4gj 8 8 ,calcium sulfate #fa4jj 8 8 ,sodium chlorid #a4ej 8 8 ,water #d4bj 8 8 ,the percentage of potash corresponding to the above formula is #aj4je4 ,it is therefore less valuable than kainit in so far as its content of potash is concerned4 ,this salt also exists in limited quantities and is not likely to become an important article of commerce4 #bda4 ,sylvin4--,one of the alteration products of carnallit is a practically pure potassium chlorid which1 as it occurs in the ,stassfurt mines is known as sylvin4 ,the alteration of the carnallit arises from its solution in water from which1 on subsequent evaporation1 the potassium chlorid is deposited alone4 ,this mineral is found in only limited quantities in the ,stassfurt deposits and it therefore does not have any great commercial importance4 #bdb4 ,sylvinit4--,this mineral has been mined in recent years in considerable quantities4 ,it is1 in fact1 only common salt carrying large quantities of potassium chlorid together with certain other accidental impurities4 ,it was probably formed by the drying up of a saline mass in such a way as not to permit the complete separation of its mineral constituents4 ,the average composition of sylvinit as it comes from the mines is given in the following table3 ,potassium chlorid #cj4ee per cent4 ,sodium chlorid #df4je 8 ,potassium sulfate #f4ie 8 ,magnesium sulfate #d4hj 8 ,magnesium chlorid #b4ed 8 ,calcium sulfate #a4hj 8 ,water and insoluble #g4bi 8 ,this salt is richer in chlorin than any other of the ,stassfurt potash minerals1 containing altogether #gi4ad per cent of chlorids4 ,its potash content amounts to #bc4jd per cent1 but in proportion to the potash which it contains1 it is relatively poorer in chlorin than kainit and carnallit4 ,on account of its high content of potash the freights on a given weight thereof as contained in sylvanit are lower than for kainit and carnallit4 #bdc4 ,kieserit4--,the mineral kieserit is essentially magnesium sulfate and it does not necessarily contain any potash salts4 ,under the name of kieserit1 however1 or bergkieserit1 there is mined a mixture of carnallit and kieserit1 which is a commercial source of potash4 ,the mixture contains the following average content of the bodies named3 ,potassium chlorid #aa4hj per cent4 ,magnesium sulfate #ba4ej 8 ,magnesium chlorid #ag4bj 8 ,sodium chlorid #bf4gj 8 ,calcium sulfate #j4hj 8 ,water #bj4gj 8 ,insoluble #a4cj 8 ,this mixture contains only about seven per cent of potash and would not prove profitable when used at a distance from the mines on account of the cost of freights4 ,it has proved valuable1 however1 for a top dressing for meadow lands in the vicinity of ,stassfurt4 #bdd4 ,schnit4--,among the ,stassfurt deposits there occurs in small quantities a mineral1 schnit1 which is composed of the sulfates of potassium and magnesium4 ,the quantity of the mineral occurring naturally is very small and therefore it has no commercial importance4 ,when1 however1 kainit is washed with water the common salt and magnesium chlorid which it contains being more soluble are the first leached out1 and the residue has approximately the composition of the pure mineral4 ,this mixture1 as prepared in the way mentioned above1 has the following average composition3 ,potassium sulfate #ej4dj per cent4 ,magnesium sulfate #cd4jj 8 ,sodium chlorid #b4ej 8 ,water #aa4fj 8 ,the percentage of potash corresponding to the above composition is #bg4b4 ,this substance being so rich in potash1 and practically free of chlorids1 is well suited to transportation to great distances and for general use in the field4 ,since1 however1 a considerable expense attends the manufacture of the artificial schnit1 the advantages above named give it very little1 if any1 advantage in competition with the other potash salts as they come from the mines4 ,it has1 however1 an especial value for the fertilization of tobacco and vineyards4 #bde4 ,potassium ,sulfate4--,several grades of potassium sulfate are found in the market for fertilizing purposes1 some of them quite pure1 containing over ninety-seven per cent of the pure sulfate4 ,the following data show the composition of a high grade and low grade potassium sulfate of commerce3 ,high grade4 ,low grade4 ,potassium sulfate #ig4bj per cent4 #ij4fj per cent4 ,potassium chlorid #j4cj 8 #a4fj 8 ,magnesium sulfate #j4gj 8 #b4gj 8 ,magnesium chlorid #j4dj 8 #a4jj 8 ,sodium chlorid #j4bj 8 #a4bj 8 ,insoluble #j4bj 8 #j4cj 8 ,water #j4gj 8 #b4bj 8 ,naturally1 high grade sulfates of this kind can only be prepared in chemical factories built especially for the work4 ,the result is that the potash per unit is raised greatly in price4 ,when1 however1 the fertilizers are to be transported to a great distance1 the saving in freight often more than compensates for the higher price of the potash4 ,it therefore happens that there are many places in this country where the actual price of potash per pound is less in high grade sulfates than in kainit or carnallit4 ,when1 in addition to this1 the especial fitness of the high grade sulfates for certain forms of fertilization1 especially tobacco growing1 is considered1 it is seen that at this distance from the mines these high grade salts are of no inconsiderable importance4 ,the percentage of potash in the high grade sulfates often exceeds fifty4 #bdf4 ,potassium ,magnesium ,carbonate4--,this salt has lately been manufactured and used to a considerable extent1 especially for tobacco fertilizing4 ,as furnished to the trade it has the following average composition3 ,potassium carbonate #ce to #dj per cent4 ,magnesium carbonate #cc to #cf 8 ,water of crystallization #be 8 ,potassium chlorid1 potassium sulfate1 and insoluble #b to #c 8 ,the content of potash1 as is seen from the above formula1 amounts to from seventeen to eighteen per cent4 ,the compound is completely dry1 is not hygroscopic1 and is1 therefore1 always ready for distribution4 ,it is especially to be recommended for all those intensive cultures where it is feared that chlorids and sulfates will prove injurious1 especially in the cultivation of tobacco4 #bdg4 ,potash in ,factory ,residues4--,the residues from the potash factories in ,stassfurt and vicinity contain considerable quantities of potash and attempts have been made to recover this waste and put it into form for fertilizing uses4 ,the waste waters of the factories are sometimes collected and evaporated1 and the residue incinerated4 ,the content of potash in these residues is extremely variable1 usually quite low1 and they1 therefore1 cannot be recommended for fertilizing purposes1 especially if they are to be transported to any distance4 #bdh4 ,quantity of ,potash ,salts ,used4--,the total quantity of potash delivered to consumers from the ,stassfurt mines in #ahia1 the last year for which complete statistics are at hand was #dac1ejh tons of kainit and sylvinit1 #ci1ddd tons of carnallit1 #ah1jgh tons of sulfate1 and #ab1dec tons of the potassium magnesium sulfate4 ,of the above quantities1 #aae1bde tons of kainit were shipped to ,north ,america1 and of the high grade sulfate mentioned1 #ac1cbb tons were sent to other countries1 and of the potassium magnesium sulfate1 #aa1jha tons were exported4 ,,methods ,,of ,,analysis4 #bdi4 ,classification of ,methods4--,to detect the presence of potash in a mixture the aid of the spectroscope may be invoked4 ,in the scale of the spectrum divided into #agj parts1 on which the sodium line falls at #ej1 potassium gives three faint rather broad bands1 two red1 falling at #ag and #bg1 and one plum-colored band1 near the extreme right of the spectrum1 at #aec4 ,potassium1 however1 does not give brilliant and well-marked spectral bands1 such as are afforded by its associates rubidium1 caesium1 sodium1 and lithium4 ,a convenient qualitative test which1 for practical purposes will be quite sufficient1 may be secured by dipping a platinum loop into a strong acid solution of the supposed potash compound1 and viewing through a piece of cobalt glass1 the coloration produced thereby when held in the flame of a bunsen4 ,the red-purple tint thereby produced should be compared with that coming from a pure potash salt similarly treated4 ,if a fertilizer sample give no indication of potash when treated as above it may be safely concluded that it does not contain any weighable quantity of potash4 ,for the estimation of the percentage of potash present in a given sample it may be safely assumed that all of value in agriculture will be given up to an aqueous or slightly acid solution if organic matter have been destroyed as indicated in a previous paragraph4 ,in the case of minerals insoluble in a dilute acid the potash may be determined by some one of the processes given in the first volume4#bjj ,the potash having been obtained in an aqueous or slightly acid 7hydrochloric7 solution1 it may be determined either by precipitation as potassium platinochlorid or as potassium perchlorate4 ,the former method is the one which has been almost exclusively used by analysis in the past1 but the latter one is coming into prominence and by reason of the greater economy attending its practice and the excellent results obtained by some analysts1 demands a generous consideration4 #bej4 ,the ,platinic ,chlorid ,method4--,the principle of this method rests on the great insolubility of the potassium platinochlorid in strong alcohol and the easy solubility of some of its commonly attending salts2 viz41 sodium1 etc41 in the same reagent4 ,before the precipitation of the potash it is necessary to remove the bases of the earths1 sulfates1 etc4 ,barium chlorid and hydroxid1 ammonium oxalate or carbonate1 sulfuric acid1 etc41 are used in conjunction or successively to effect these purposes in the manner hereinafter described4 ,the filtrate and washings containing the potash are evaporated to dryness and gently ignited to expel excess of ammonium salts and in the residue taken up with water and acidulated with hydrochloric acid1 the potash is precipitated with platinic chlorid solution4 ,the best methods of executing the analysis follow4 #bea4 ,the ,official ,agricultural ,method4--,this method is based on the processes at first proposed by ,lindo#bja and ,gladding1#bjb and is given below as adapted to mixed fertilizers and mineral potash salts4#bjc 7#a7 ,in ,superphosphates4--,boil ten grams with #cjj cubic centimeters of water thirty minutes4 ,to the hot solution add ammonia in slight excess1 and then a sufficient quantity of ammonium oxalate to precipitate all the lime present2 cool and make up to half a liter1 mix thoroughly1 and filter through a dry filter2 evaporate fifty cubic centimeters1 corresponding to one gram1 nearly to dryness1 add one cubic centimeter of dilute sulfuric acid 7#a to #a71 evaporate to dryness and ignite to whiteness4 ,as all the potash is in form of sulfate1 no loss need be apprehended by volatilization of potash1 and a full red heat must be maintained until the residue is perfectly white4 ,this residue is dissolved in hot water1 plus a few drops of hydrochloric acid1 and a slight excess of platinum solution is added4 ,this solution is then evaporated to a thick paste in a small dish1 and eighty per cent alcohol added4 ,in evaporating1 special precaution should be taken to prevent absorption of ammonia4 ,the precipitate is washed thoroughly with alcohol by decantation and on the filter1 as usual4 ,the washing should be continued even after the filtrate is colorless4 ,ten cubic centimeters of the ammonium chlorid solution1 prepared as hereinafter directed1 are run through the filter1 or the washing may be performed in the dish4 ,the ten cubic centimeters will contain the bulk of the impurities1 and are thrown away4 ,fresh portions of ten cubic centimeters of the ammonium chlorid are run through the filter several times 7#e or #f74 ,the filter is then washed thoroughly with pure alcohol1 dried1 and weighed as usual4 ,care should be taken that the precipitate is perfectly soluble in water4 ,the platinum solution used contains one gram of metallic platinum in every ten cubic centimeters4 ,to prepare the washing solution of ammonium chlorid1 place in a bottle #ejj cubic centimeters of water and #ajj grams of ammonium chlorid and shake till dissolved4 ,now pulverize five or ten grains of potassium platinochlorid1 put in the bottle and shake at intervals for six or eight hours2 let settle over night1 then filter off the liquid into a second bottle4 ,the first bottle is then ready for preparation of a fresh supply when needed4 7#b7 ,potassium ,chlorids4--,in the analysis of these salts an aliquot portion of the solution1 containing a half gram1 is evaporated with forty cubic centimeters of the platinum solution and a few drops of hydrochloric acid1 and washed as before4 7#c7 ,potassium ,sulfate1 ,kainit1 ,etc4--,in the analysis of kainit1 dissolve ten grams of the pulverized salt in #cjj cubic centimeters of boiling water1 add ammonia to slight excess1 then a sufficient quantity of ammonium oxalate to throw down all lime present2 cool and make up to half a liter1 mix thoroughly1 and filter on a dry filter2 from twenty-five cubic centimeters1 corresponding to a half gram1 proceed to remove the ammonia1 as in the analysis of superphosphates2 dissolve the residue in hot water1 plus a few drops of hydrochloric acid1 and add fifteen cubic centimeters of platinum solution4 ,in the analysis of high-grade sulfate and of double-manure salt 7potassium sulfate1 magnesium sulfate1 containing about twenty-seven per cent of potassium oxid71 make up the solution as above1 but omit the precipitation1 evaporation1 etc42 to an aliquot part equal to a half gram add fifteen cubic centimeters of platinum solution4 ,in all cases special care must be taken in the washing with alcohol to remove all the double platinum sodium chlorid which may be present4 ,the washing should be continued some time after the filtrate is colorless4 ,twenty-five cubic centimeters of the ammonium chlorid solution are employed instead of ten cubic centimeters1 and the twenty-five cubic centimeters poured through at least six times to remove all sulfates and chlorids4 ,wash finally with alcohol2 dry and weigh as usual4 #beb4 ,alternate ,method for ,potash4--,boil ten grams of the prepared sample for thirty minutes with #cjj cubic centimeters of water1 and1 after cooling and without filtering1 make up to one liter and filter through a dry filter4 ,if the sample have ten per cent of potassium oxid1 use fifty cubic centimeters of the filtrate2 if less than ten per cent of potassium oxid 7ordinary potash fertilizers71 use #ajj cubic centimeters of the filtrate4 ,in each case make the volume up to #aej cubic centimeters1 heat to #ajj1 and add1 drop by drop with constant stirring1 a slight excess of barium chlorid1 and1 without filtering1 in the same manner add barium hydrate in slight excess4 ,filter while hot and wash until the precipitate is free of chlorids4 ,add to the filtrate one cubic centimeter of strong ammonium hydrate1 and then a saturated solution of ammonium carbonate1 until the excess of barium is precipitated4 ,heat and add1 in fine powder1 a half gram of pure oxalic acid or #j4ge gram of ammonium oxalate4 ,filter1 wash free of chlorids1 evaporate the filtrate to dryness in a platinum dish1 and ignite carefully over the free flame1 below red heat1 until all volatile matter is driven off4 ,the residue is digested with hot water1 filtered through a small filter1 and washed with successive small portions of water until the filtrate amounts to thirty cubic centimeters or more4 ,to this filtrate1 add two drops of hydrochloric acid1 in a porcelain dish1 and from five to ten cubic centimeters of a solution of ten grams of platinic chlorid in #ajj cubic centimeters of water4 ,the mixture is evaporated on a water-bath to a thick sirup1 as above1 treated with alcohol of eighty per cent strength1 washed by decantation1 collected in a gooch or other form of filter1 washed with strong alcohol1 afterwards with five cubic centimeters of ether1 dried for thirty minutes at #ajj1 and weighed4 ,it is desirable1 if there be an appearance of foreign matter in the double salt1 that it should be washed1 according to the previous method1 with ten cubic centimeters of the half-concentrated solution of ammonium chlorid1 which has been saturated by shaking with potassium platinochlorid4 #bec4 ,method of ,solution for ,organic ,compounds4--,in case the potash is contained in organic compounds1 like tobacco stems1 cottonseed hulls1 etc41 weigh ten grams1 saturate with strong sulfuric acid1 and ignite in a muffle to destroy organic matter4 ,add a little strong hydrochloric acid to moisten the mass and warm slightly so as to loosen it in the dish4 ,proceed then as in the lindo-gladding or alternate method4 #bed4 ,factors4--,the use of the factors #j4cjef for converting potassium platinochlorid to potassium chlorid and #j4aicjh for converting it to potassium oxid is advised4 ,the latter number is almost identical with that used by the ,halle and ,stassfurt chemists viz41 #j4aibg and #j4aibh respectively4 #bee4 ,methods ,used at the ,halle ,station4--7#a7 ,in ,kainits and other ,mineral ,salts of ,potash4#bjd--;,five grams of the prepared sample are boiled for half an hour in a half liter flask with from twenty to thirty cubic centimeters of concentrated hydrochloric acid and #ajj cubic centimeters of water1 and afterwards as much water added as is necessary to fill the flask about three quarters full1 and the sulfuric acid is then precipitated with barium chlorid4 ,to avoid an excess of barium chlorid the solution used is of known strength and is added first in such quantity as would precipitate the sulfuric acid from a kainit of low sulfuric acid content4 ,the mixture is then boiled1 allowed to settle and tried with a dropping tube containing barium chlorid4 ,if a further precipitate be given a few drops more of barium chlorid solution are added1 again boiled and allowed to settle4 ,this is continued until barium chlorid gives no precipitation4 ,after the barium chlorid gives no more precipitate a drop of dilute sulfuric acid is added to test for excess of barium4 ,the operation is continued with the sulfuric acid until it no longer gives a precipitate of barium sulfate4 ,by the alternate use of the barium chlorid and sulfuric acid the exact neutral point can soon be secured4 ,when this point is reached the liquid is allowed to cool1 the flask is filled to the mark1 its contents filtered1 and of the filtrate fifty cubic centimeters1 equal to half a gram of the substance1 taken for further estimation4 ,this quantity is evaporated on a water-bath to a sirupy consistence in a porcelain dish with ten cubic centimeters of platinic chlorid4 ,the platinic chlorid solution should contain one gram of platinum in each ten cubic centimeters4 ,the residue is treated with eighty per cent alcohol and1 with stirring1 allowed to stand for an hour4 ,the precipitate is then collected on a gooch1 either of platinum or porcelain1 washed about eight times with eighty per cent alcohol and the potassium platinochlorid dried for two hours at #ajj4 ,after weighing the precipitate is dissolved in hot water and the residue washed under pressure1 first with hot water and then with alcohol4 ,the crucible with the asbestos felt is dried at #ajj and weighed4 ,any impurities which the double salt may have carried down with it are left on the filter and the weight of the original precipitate can thus be corrected4 ,the weight of potassium platinochlorid is multiplied by #j4aibg and the product corresponds to the weight of ,k,o in the sample taken4 7#b7 ,estimation of ,potash in ,guanos and ,other ,fertilizers containing ,organic ,substances4--,ten grams of the substances are carefully incinerated at a low temperature in a platinum dish4 ,after ignition the contents of the dish are placed in a half liter flask and boiled for an hour with hydrochloric acid and a few drops of nitric acid4 ,the sulfuric acid can then be precipitated directly with barium chlorid1 or better1 allow the flask to cool1 fill to the mark1 filter and treat an aliquot part of the filtrate with barium chlorid as described above4 ,the filtrate from the separated sulfate of barium is neutralized with ammonia and all the bases1 with the exception of magnesia and the alkalies1 precipitated with ammonium carbonate2 boil1 fill to the mark and filter4 ,of this filtrate evaporate from #ajj to #bjj cubic centimeters in a platinum dish4 ,after evaporation the ammonium salts are driven off by careful ignition1 the residue taken up with hot water and filtered through as small a filter as possible into a porcelain dish2 the magnesia remaining in the precipitate4 ,the filtrate is acidified with a few drops of hydrochloric acid1 ten cubic centimeters of platinic chlorid added and the further determination conducted as with kainit4 #bef4 ,dutch ,method4--,the process used at the ,royal ,agricultural ,station of ,holland is almost identical with that employed at ,halle4#bje ,a4 ,method for ,stassfurt and other ,potash ,salts4--,the necessary reagents are3 #a4 ,a dilute solution of barium chlorid3 #b4 ,a solution of platinic chlorid containing one gram of platinum in ten cubic centimeters3 ,it must be wholly free from platinous chlorid and nitric acid1 and partially freed from an excess of hydrochloric acid by repeated evaporations with water4 #c4 ,alcohol of eighty per cent strength by the volume3 ,the methods of bringing the potash into solution and of precipitating the sulfuric acid are the same as for the ,halle process described above4 ,add then twenty cubic centimeters of the platinum solution and evaporate the mixture nearly to dryness4 ,add a sufficient quantity of eighty per cent alcohol and stir for some time4 ,allow to stand and then filter through a gooch dried at #abj4 ,finally wash with eighty per cent alcohol1 dry at #abj1 and weigh4 ,b4 ,method for ,potash ,superphosphate and other mixed ,fertilizers4--,the reagents necessary are the same as under ,a1 and1 in addition1 a saturated solution of barium hydrate and a solution of ammonium carbonate mixed with ammonia4 ,boil twenty grams of the substance with water for half an hour1 cool1 make up to half a liter and filter4 ,boil fifty cubic centimeters of the filtrate1 and add barium chlorid till no more precipitate forms4 ,mix with baryta water to strong alkaline reaction1 cool1 make up to #ajj cubic centimeters and filter4 ,raise fifty cubic centimeters of the filtrate to the boiling temperature and add ammonium carbonate solution till no more precipitate forms3 ,cool1 make up to #ajj cubic centimeters and filter4 ,transfer fifty cubic centimeters of the filtrate to a platinum dish1 evaporate and heat the residue1 avoiding too high a temperature1 till the ammonia salts are expelled4 ,dissolve the residue in water1 filter1 and treat the filtrate as described under ,a4 #beg4 ,swedish ,methods4--,the ,swedish chemists determine the potash in mineral salts by the platinum chlorid process1 but with certain variations from the processes already given4 ,the manipulation is conducted as follows3#bjf ,weigh one gram of the sample to be examined and pour about #cjj cubic centimeters of hot water over it in a beaker and filter after complete solution2 add one cubic centimeter of hydrochloric acid1 heat nearly to boiling1 add dilute barium chlorid solution from a pipette or burette in a very fine stream stirring1 slowly and carefully1 till all sulfuric acid is completely precipitated1 and only a trace of the precipitant is in excess4 ,if the precipitation be conducted in the way given the barium sulfate will come down in crystalline condition1 and settle rapidly within a few minutes1 and almost immediately after the precipitation is finished may be filtered clear4 ,the filtrate and washings from the barium sulfate are brought into a liter flask2 fill this to the mark1 take out fifty cubic centimeters with a pipette1 evaporate the greater portion on a water-bath in a porcelain dish1 transfer the residue by means of ammonia-free water to a beaker of fifty cubic centimeters capacity1 add ten cubic centimeters of platinic chlorid solution1 stir well with a glass rod1 evaporate on a water-bath to a sirupy condition1 allow to cool1 and if the residue be too dry1 add a few drops of water to allow the sodium platinochlorid to take up crystal water with certainty1 stir well1 add alcohol after a few minutes1 mix carefully1 leave the mixture standing for a while in the beaker covered with a watch glass1 stirring occasionally2 finally decant the solution1 which must be of a dark yellow color1 through a very small filter1 wash the precipitate in the beaker repeatedly with small quantities of alcohol and decant2 then transfer the precipitate to the filter1 wash with alcohol1 dry the filter and the precipitate at a gentle heat till all alcohol has evaporated1 carefully transfer the contents of the filter to a watch glass placed on white glazed paper2 dissolve the potassium platinochlorid still remaining on the filter in small quantities of boiling water1 evaporate the filtrate on a water-bath in an accurately weighed platinum dish to dryness and transfer the same to the main portion of the chlorid from the watch glass4 ,in order to obtain the salt free of the corresponding combinations of sodium1 barium1 calcium1 and magnesium1 which salts1 although soluble in alcohol1 may make the salt impure1 before weighing1 treat the precipitate twice with small quantities of cold water which will dissolve these impurities2 evaporate the solution after addition of one cubic centimeter of platinic chlorid nearly to dryness on a water-bath1 treat the residue in the same way as given before1 add the small quantity of potassium platinochlorid which is hereby obtained together with the main portion to the platinum dish1 dry at #acj1 and weigh4 ,only after having been treated in this way may the precipitated potassium platinochlorid be considered absolutely pure4 ,the ,stassfurt salts contain magnesia1 often in large quantities and as a consequence the potassium platinochlorid precipitated directly is likely to be contaminated therewith4 #beh4 ,methods for the ,analysis of ,carnallit1 ,kainit1 ,sylvinit1 and ,kieserit4--,the chemists of the ,german ,potash ,syndicate use the following methods in the analysis of the raw products mentioned above4#bjg 7#a7 ,preparation of the ,sample4--,it is advisable to take from a large well mixed mass at least half a kilogram for the analytical sample and this should be ground to a fine powder in a mill or mortar4 7#b7 ,estimation of the ,potash by the ,precipitation ,method4--,in a half liter flask are placed #ce4gj grams of kainit or sylvinit1 or #cj4ef grams of carnallit or bergkieserit1 which are boiled with #cej cubic centimeters of water after the addition of ten cubic centimeters of hydrochloric acid4 ,after cooling the flask is filled to the mark with water1 well shaken1 and its contents filtered4 ,fifty cubic centimeters of the filtrate are treated in a #bjj cubic centimeter flask with a solution of barium chlorid1 the flask filled to the mark1 well shaken1 and its contents filtered4 ,twenty cubic centimeters of the filtrate1 corresponding to #j4cegj or #j4cjef gram of the substance1 are treated with five cubic centimeters of platinic chlorid solution and the potassium estimated according to the usual methods4 7#c7 ,estimation of ,potash 7,k,o7 in ,raw ,potash ,salts4--7a7 ,for the determination of potash alone in carnallit1 kainit1 and sylvinit one hundred grams of the well-mixed sample are put into a graduated flask holding one liter and dissolved by boiling with half a liter of water1 acidulated with ten cubic centimeters of hydrochloric4 ,the purpose of adding hydrochloric acid is to bring any polyhalit that might be present in the salts into solution and which it is difficult to dissolve in pure water4 ,after dissolving and cooling the flask is filled up to the mark4 ,the solution1 after mixing1 is filtered through a dry filter and #ajj cubic centimeters of the filtrate1 corresponding to ten grams substance1 are put into a half liter flask by means of a pipette4 ,after the addition of #bjj-cjj cubic centimeters of water the solution is heated to boiling and the sulfuric acid accurately precipitated with normal barium chlorid solution1 containing #ajd grams of the dry salt in one liter4 ,the volume of the precipitate is calculated from the amount of barium solution used and from the specific gravity of the barium sulfate4 ,after cooling1 the flask is filled up with water as far above the mark as equals the volume of the calculated barium precipitate1 and1 after thorough mixing1 the solution is filtered again through a dry filter4 ,fifty cubic centimeters of this filtrate1 corresponding to one gram substance1 are evaporated upon the water-bath with a sufficient amount of platinic chlorid4 ,the residue of potassium platinochlorid is washed with ninety per cent alcohol1 dried at #abj1 and weighed4 7b7 ,if it be desired to determine separately the quantity of potash present in the form of sulfate and in the form of chlorid1 as for example in kainit and in sulfate of potash1 or if it is to be determined whether potassium sulfate is in combination with a proportionate amount of magnesium chlorid1 as in kainit1 or in combination with magnesium sulfate alone1 as in schnit1 it then becomes necessary to determine besides potash the percentages of chlorin1 sulfuric acid1 lime1 magnesia1 the total alkalies1 water1 and the residue insoluble in water4 ,for this purpose #ajj grams of the sample are dissolved1 the solution is filtered1 the filter washed1 and the filtrate made up to one liter2 a part of the liquid is taken for the determination of sulfuric acid2 by precipitating with barium chlorid1 and another part for the determination of lime and magnesia4 ,for the determination of the alkali chlorids1 #ajj cubic centimeters of the solution1 corresponding to ten grams substance1 are acidulated with hydrochloric1 and1 after heating to boiling1 the sulfuric acid is completely precipitated with barium chlorid1 with the precaution of using not more of the barium solution than is necessary for the complete precipitation4 ,fifty cubic centimeters of the filtered solution1 corresponding to one gram substance1 are evaporated to dryness in order to drive off the hydrochloric acid4 ,magnesium chlorid is decomposed by igniting with oxalic acid or with mercuric oxid4 ,after ignition1 the residue is moistened with a little ammonium carbonate for the purpose of converting the calcium oxid that may have been formed into calcium carbonate4 ,the alkali chlorids1 which are entirely free of lime and magnesia1 are weighed1 and potassium chlorid is determined by means of platinic chlorid4 ,the amount of sodium chlorid is obtained by deducting potassium chlorid from the mixed chlorids4 ,for the water determination five grams of the sample are ignited and the loss of weight is determined4 ,the ignited mass is dissolved in water1 and for the purpose of determining the quantity of magnesium chlorid that may have been decomposed by the ignition the percentage of chlorin is determined by titration4 ,the difference in the contents of chlorin before and after ignition is subtracted from the loss in weight1 after allowance has been made for the absorption of oxygen and for the loss of hydrogen4 ,the rest is water4 ,the results obtained are calculated in the following manner3 ,from the total amount of the sulfuric acid found1 that portion is deducted which is combined with calcium as calcium sulfate2 the rest of the sulfuric acid is divided into two equal parts for the purpose of calculating the contents of potassium sulfate and magnesium sulfate1 according to the molecular proportion in which these salts are present in kainit and in schnit4 ,if there be an excess of potash left uncombined with sulfuric acid1 then it is in the form of potassium chlorid2 likewise the amount of magnesia1 uncombined with sulfuric acid1 is to be reckoned as magnesium chlorid4 ,the result of this calculation will tell how much potash is in the form of kainit 7,k,,so1 ,mg,s,o1 ,mg,cl with #f;,h,o7 and how much of it is in the form of schnit 7,k,,so1 ,mg,s,o1 with #f;,h,o7 and how much in the form of potassium chlorid4 ,the sodium is reckoned as sodium chlorid4 7c7 ,in calculating the contents of potash1 of potassium chlorid1 and of potassium sulfate from the weighed potassium platinochlorid1 the factors #j4aibh1 #j4cjef1 and #j4ceff are used1 assuming that the atomic weight of platinum is #aig4ah4 7d7 ,the two methods which have been described under a and b1 and which are in common use in the ,stassfurt potash industry1 i4 e41 the so-called precipitation method1 and the oxalic acid method1 give almost identical results4 ,the first method1 however1 deserves preference on account of greater simplicity in cases where potash alone is to be determined4 ,finkner's method likewise gives results which agree well with the results obtained by the customary methods4 ,it consists in evaporating the salt solution with a sufficient quantity of platinic chlorid without previously removing the sulfuric acid1 reducing the potassium platinochlorid1 and weighing the metallic platinum4 ,the following are the results of comparative analyses3 #a4 ,after the precipitation method #bb4jb per cent ,k,cl #b4 ,after the oxalic acid method #bb4jc per cent ,k,cl #c4 ,after ,finkner's method #bb4ja per cent ,k,cl ,in another sample of carnallit the following results were obtained3 #a4 ,after the precipitation method #ag4hh per cent ,k,cl #b4 ,after the oxalic acid method #ag4hh per cent ,k,cl ,in a third sample of carnallit the content of potassium chlorid was as follows3 #a4 ,after the precipitation method #ah4dd per cent #b4 ,after the oxalic acid method #ah4ch per cent ,the ,anhalt chemists object to precipitating the sulfuric acid and alkaline earths with barium oxid and ammonium carbonate1 and afterwards the potash with platinic chlorid4 ,the results obtained with this method are1 according to them1 very inaccurate1 and always too low4 ,this is explained by the fact that it is impossible to precipitate sulfuric acid without at the same time precipitating some of the potash1 unless it be in an acid solution4 ,a separation of the alkaline earths1 if potash alone is to be determined1 is superfluous1 for the reason that calcium and magnesium platinochlorid are soluble in ninety per cent alcohol1 even with more facility than sodium platinochlorid4 #bei4 ,methods for ,concentrated ,potash ,salts4--,in the preceding paragraphs have been given the methods used by the ,stassfurt syndicate for the estimation of potash in the raw salts as they come from the mines4 ,following are the methods used by the same syndicate for the concentrated approximately pure compounds and the other salts which accompany them4 ,potassium ,chlorid4--,the following process is used for the estimation of potassium and other constituents of the high grade chlorids of commerce4 ,in a half liter flask are placed #g4fdje grams of the finely powdered sample1 which is dissolved and made up to the mark4 ,with salts which contain more than half a per cent of sulfuric acid the preliminary conversion of the sulfates into the corresponding chlorin compounds1 by precipitation with barium chlorid solution1 is necessary4 ,twenty cubic centimeters of the above solution1 corresponding to #j4cjef gram of the salt1 are placed in a flat porcelain dish having a diameter of about ten centimeters and1 after the addition of five cubic centimeters of the platinic chlorid solution1 evaporated on the water-bath with constant stirring until1 after cooling1 the sirupy liquid passes quickly into a fine crystalline condition4 ,the residue is rubbed into a fine powder with a glass rod1 mixed with twenty cubic centimeters of ninety-six per cent alcohol and dried at #abj to a constant weight4 ,it is weighed while warm and brought on a moistened filter with alcohol1 care being taken that the liquid does not touch the edge of the filter4 ,the filtration can be carried on under a moderate pressure4 ,the complete washing of the potassium platinochlorid can be easily accomplished upon the filter4 ,the filter and the precipitate1 after as much of the alcohol wash has been removed as is possible1 are dried at #abj to constant weight and weighed while still warm4 ,one milligram of the potassium platinochlorid thus obtained corresponds to a tenth per cent of potassium chlorid4 ,estimation of ,sodium ,chlorid4--,for the estimation of the sodium chlorid which may be present in the potassium chlorid twelve and a half grams of the latter salt are dissolved in a quarter liter flask with twenty-five cubic centimeters of boiling water after the addition of a little potassium carbonate for the purpose of converting the magnesium and calcium compounds into carbonates4 ,after filtration #ajj cubic centimeters corresponding to five grams of the salt are evaporated to dryness in a porcelain or platinum dish after the addition of a few drops of concentrated hydrochloric acid in order to convert any calcium carbonate which may be present into chlorid4 ,the residue is gently ignited and weighed4 ,in this mixture of potassium and sodium chlorids the potassium chlorid may be estimated in the usual way and the sodium chlorid determined by difference or the respective proportions of the two bases may be calculated after the determination of the total chlorin by precipitation with a standard solution of silver nitrate4 ,estimation of ,magnesium ,chlorid4--,in order to estimate the amount of magnesium chlorid in high grade muriate of potash1 twenty-five grams of the latter salt are dissolved in a half liter flask and treated with ten cubic centimeters of a normal solution of potash lye4 ,the flask is then filled to the mark with water1 thoroughly shaken and its contents filtered4 ,fifty cubic centimeters of the filtrate are then titrated with one-tenth normal sulfuric acid4 ,the calcium compounds which remain in solution do not influence the result4 ,the quantity of magnesium chlorid originally present corresponds to the number of cubic centimeters of the normal potash lye which has disappeared in the operation4 ,the reaction which takes place is represented by the following equation3 ,mg,cl #b,,koh ,mg,o,h #b,k,cl4 ,potassium ,sulfate4--,the quantity of potassium sulfate contained in the high grade sulfates of commerce is determined in the following manner3 ,in a half liter flask are placed #h4ibce grams of the finely ground sample which is dissolved in about #cej cubic centimeters of boiling water after the addition of twenty cubic centimeters of hydrochloric acid4 ,the sulfuric acid is thrown out by the addition1 drop by drop1 of a barium chlorid solution1 the contents of the flask being kept boiling meanwhile and thoroughly stirred4 ,from time to time the addition of the barium chlorid is stopped and the upper part of the liquid allowed to become clear by the subsidence of the barium sulfate4 ,it is then noticed whether or not an additional drop of the barium chlorid solution produces a turbidity4 ,any excess of barium chlorid is removed by the careful addition of sulfuric acid4 ,after the precipitation is complete and the contents of the flask are cooled1 it is filled up to the mark with water and its contents filtered4 ,twenty cubic centimeters of the filtrate1 corresponding to #j4ceg gram of the original salt are precipitated by platinic chlorid in the usual manner and the resulting potassium platinochlorid collected and weighed4 ,one milligram of the potassium platinochlorid thus obtained corresponds to one-tenth per cent of potassium sulfate in the original salt4 ,to the percentage of potassium sulfate thus found three-tenths per cent are to be added for a correction when high grade potassium sulfate is taken4 ,if the sample be a high grade sulfate of potassium and magnesium no correction should be applied4 ,estimation of ,potassium ,chlorid and ,potassium ,sulfate in ,calcined ,manurial ,salts4--,in these salts #ae4bha grams for potassium chlorid or #ag4hdg grams for potassium sulfate are dissolved in a half liter flask after the addition of ten cubic centimeters of hydrochloric acid4 ,the flask is filled to the mark and its contents filtered and #bej cubic centimeters placed in a half liter flask and treated with barium chlorid solution as indicated above4 ,the rest of the operation is exactly as has been described4 ,in each case one milligram of the potassium platinochlorid corresponds to one-tenth per cent of the desired salt4 ,estimation of ,magnesium ,sulfate in ,kieserit4--,ten grams of the finely powdered kieserit are boiled for one hour in a half liter flask two-thirds full of water4 ,after cooling1 from fifty to sixty cubic centimeters of double normal potash lye and twenty cubic centimeters of a ten per cent neutral potassium oxalate solution are added1 the flask filled to the mark1 and after being well shaken and standing for a quarter of an hour1 filtered4 ,the reaction is represented by the formula ,mg,s,o #b,,koh ,mg,o,h ,k,,so4 ,fifty cubic centimeters of the filtrate are then titrated with one-tenth normal sulfuric acid4 ,to the percentage of magnesium sulfate found by this process two-tenths per cent are to be added as a correction4 ,barium ,chlorid ,solution4--,dissolve #abb grams of crystallized barium chlorid in water in a liter flask4 ,add fifty cubic centimeters of hydrochloric acid and water to the mark and shake well4 #bfj4 ,the ,barium ,oxalate ,method4--,the principle of this process1 worked out by ,schweitzer and ,lungwitz#bjh is based on the fact that in an ammoniacal solution1 by means of barium oxalate1 all the alkaline earths can be precipitated as oxalates1 and sulfuric acid in similar circumstances can be thrown down as a barium salt and the iron and alumina as hydroxids4 ,the reagents used to secure this precipitation are ammonia and barium oxalate4 ,for the determination of potash in a superphosphate the analytical process is conducted as follows3 ,ten grams of the superphosphate are mixed with half a liter of water and fifteen grams of barium oxalate dissolved in hydrochloric acid4 ,the mixture is boiled for twenty minutes and treated with some hydrogen peroxid to oxidize any ferrous iron that may be present4 ,afterwards the solution is made alkaline with ammonia4 ,after cooling1 it is made up to a given volume 7half a liter7 and filtered4 ,an aliquot part of the filtrate is evaporated to dryness1 ignited1 extracted with hot water and1 after the addition of a few drops of hydrochloric acid1 the potassium is precipitated with platinic chlorid1 and collected and weighed in the usual manner3 ,or the ignited residue may be dissolved directly in dilute hydrochloric acid and the rest of the process carried out as indicated4 ,in kainit the process is conducted as follows3 ,ten grams of the powdered sample are treated with a hydrochloric acid solution of the barium oxalate containing ten grams of the salt4 ,the rest of the operation is conducted as described above4 ,in the use of this method it is important that always enough of the barium oxalate solution be employed to fully saturate all the sulfuric acid which may be present4 #bfa4 ,method of ,de,roode for ,kainit4--,all the potash contained in kainit1 according to de ,roode1 passes readily into aqueous solution4#bji ,on evaporating this aqueous solution to a pasty condition with enough platinic chlorid to unite with all the halogens present all the other bodies can be washed out of the potassium platinochlorid by ammonium chlorid solution and the pure platinum salt thus obtained1 which is washed and dried in the usual way4 ,de ,roode therefore asserts that it is quite useless to previously precipitate the solution of kainit with barium chlorid1 ammonium oxalate1 or carbonate4 ,before the addition of alcohol to the residue obtained by evaporation with platinic chlorid the sodium sulfate present renders the platinum salt sticky and difficult to wash1 but the disturbing sodium compound can be readily removed by washing with ammonium chlorid solution4 ,the method of direct treatment has the advantage of avoiding the occlusion of potash in other precipitates and the danger of loss on ignition4 ,the method as used by de ,roode gives results about one-tenth per cent higher than are obtained by the official processes4 #bfb4 ,the ,calcium ,chlorid ,method4--,huston has proposed the addition of calcium chlorid to the solution of a fertilizer in the determination of potash1 in order to furnish sufficient calcium to form tricalcium phosphate with all the phosphoric acid present1 and thereby permit of the use of platinum dishes in the lindo-gladding method4#baj ,in testing this process de ,roode found that when sufficient calcium chlorid was added to combine with all the phosphoric acid present and then ammonia added in excess and a portion of the solution filtered1 no test for phosphoric acid could be obtained2 but1 that if in addition to the calcium chlorid and ammonia1 some ammonium oxalate or carbonate was added1 a filtered portion of the solution gave a test for phosphoric acid4#baa ,this is accounted for by the fact that the calcium phosphate1 which is precipitated by the ammonia1 is changed by the ammonium oxalate or carbonate into calcium oxalate or carbonate and ammonium phosphate1 so that the very object for which the calcium chlorid was added is defeated by the addition of the ammonium oxalate or carbonate4 ,in order to make the use of calcium chlorid effective it is necessary to filter the liquid from the precipitate formed by the calcium chlorid and ammonia and then add the ammonium oxalate or carbonate to the filtrate4 ,this necessitates two separate filtrations and makes the proposed method of ,huston as long as the old process4 #bfc4 ,rapid ,control ,method for ,potash ,salts4--,for rapid control work where great accuracy is not required ,albert recommends that the finely ground substance be placed in a liter flask and about #djj cubic centimeters of water added and three cubic centimeters of hydrochloric acid4#bab ,after boiling1 barium chlorid is added drop by drop as long as a precipitate is produced4 ,after cooling1 the flask is filled to the mark and shaken and its contents filtered through a dry filter4 ,an aliquot portion of the filtrate is evaporated with platinum chlorid solution in a smooth porcelain dish almost to dryness and the mass treated with alcohol1 filtered through a weighed filter1 and well washed with alcohol4 ,the filter is then dried in an air-bath to a constant weight4 ,for the different kinds of potash materials on the market the following proportions are recommended3 ,kainit or ,carnallit4--,twenty grams in one liter3 ,fifty cubic centimeters of the filtrate are evaporated with forty of platinic chlorid solution4 ,the weight of potassium platinochlorid obtained #ai4c gives the per cent of ,k,o4 ,sulfate of ,potash4--,fifteen grams in one liter3 ,twenty cubic centimeters of the solution are evaporated with fifteen of platinic chlorid4 ,the weight of potassium platinochlorid obtained #fd4cc gives the per cent of ,k,o4 ,potassium ,chlorid4--,ten grams in one liter3 ,twenty-five cubic centimeters are evaporated with fifteen of platinic chlorid solution4 ,the weight of the precipitate obtained #gg4b gives the per cent of ,k,o4 #bfd4 ,weighing the ,precipitate as ,metallic ,platinum4--,hilgard calls attention to the difficulty of weighing the double chlorid of platinum and potash as such1 although he acknowledges that in the gooch this weighing can be made with great accuracy4#bac ,he prefers to estimate the platinum in the metallic state and uses for this purpose a platinum crucible the inside of which1 half way up from the bottom1 is coated with a layer of platinum sponge1 which is conveniently prepared by the decomposition of a few decigrams of the platinum double salt by inclining the crucible and rotating it during the progress of the reduction1 using about a quarter of an hour in all4 ,the platinum sponge produced in this way greatly favors the decomposition of the double salt for analytical purposes4 ,the decomposition of the salt takes place quickly and quietly and at conveniently low temperatures4 ,when the decomposition is ended the crucible is strongly heated so as to hold the platinum sponge1 which is produced1 together sufficiently to prevent its being removed in the subsequent washing of the crucible by decantation4 ,by the ignition at a high temperature necessary to secure this1 the greater part of the calcium chlorid is volatilized4 ,after cooling1 a few drops of concentrated hydrochloric acid are placed in the crucible and if the slightest yellow color be shown the acid is evaporated and the ignition repeated1 with the addition of a little oxalic acid4 ,in most cases the slight yellow color produced comes from a trace of iron and will therefore appear again after the second ignition4 ,the crucible is subsequently washed by repeated decantations1 finally with boiling water1 and after drying is ignited and weighed4 ,the advantage of this process is that without further trouble the reduced metal is completely freed of any salts of the alkaline earths1 etc41 which have been carried down with it and also from any of the uncombined sodium chlorid which may not have been washed out by the alcohol4 ,in fact1 the results obtained in this way are nearly always lower than those obtained through the direct weighing of the double salt1 and the wash water which is first poured off contains1 as a rule1 traces of the alkaline earths and almost without exception some sodium chlorid4 ,correction for the filter ash is unnecessary because the ash is completely dissolved by the treatment received4 ,the platinum sponge which is collected in the crucible in this way is removed in case it does not adhere to the sides and the crucible is then ready for the next operation4 #bfe4 ,sources of ,error in the ,platinum ,method4--,in the comparative work done in the determination of potash by the members of the ,association of ,official ,agricultural ,chemists there has been noted1 from year to year1 marked differences in the data obtained by different analysts4 ,such differences often are due to personal errors1 or a failure to accurately follow the directions for manipulation4 ,sometimes1 however1 they are due to sources of error in the processes employed4 ,in the platinum method these sources of error have been long known to exist4 ,chief among these is the remarkable facility with which potash becomes incorporated with the precipitates of other bodies4 ,the character and magnitude of some of these errors have lately been studied by ,robinson4#bad ,many precipitates occlude potash and hold it so firmly that it cannot be washed out with hot water although the potash compounds present in the precipitate are perfectly soluble4 ,it appears to be a kind of molecular adhesion4 ,barium sulfate has this property of attaching potash molecules in a high degree1 and ferric and aluminic compounds only to a slightly less extent4 ,to reduce the losses1 consequent on the conditions just mentioned1 to a minimum1 the sulfuric acid and earthy bases should be very slowly precipitated1 with violent agitation1 at a boiling temperature4 ,another source of loss in the platinum method arises from the use of a solution of ammonium chlorid for washing the potassium platinochlorid precipitate4 ,there is danger here1 not only of the solution of the impurities present in the precipitate1 but also of a double decomposition by means of which some ammonium may be substituted for the potassium in the washed product4 ,in the official method1 moreover1 there is danger of securing a final precipitate which may contain traces of calcium and magnesium sulfates when these bodies are abundantly present in the sample taken for analysis4 ,the careful analyst must guard against these sources of error1 but it is probably true that he will never secure a practically chemically pure precipitate of potassium platinochlorid when working on the mixed fertilizers found in commerce4 #bff4 ,effect of ,concentration on the ,accuracy of ,potash ,analysis4--,winton has also studied the sources of error in the determination of potash as platinochlorid1 especially with reference to the effect of the concentration of the solution at the time of precipitation4#bae ,he finds that the method of precipitating in concentrated solutions and drying the potassium platinochlorid at #acj1 depends for its accuracy upon the mutual compensation of three errors2 viz41 7#a7 to the solubility of the potassium salt in eighty per cent alcohol1 7#b7 to the presence of water in the crystals which is not driven off at #acj1 and 7#c7 the use of a factor based on the wrong atomic weight of platinum4 ,he finds1 further1 that the error due to the presence of water occluded in the crystals can be reduced to a minimum1 and the process of drying greatly simplified1 by adding the solution of platinum chlorid to the potash solution in a dilute condition1 not exceeding one per cent in strength4 ,the potassium platinochlorid thus produced can be very effectively dried at #ajj4 ,the error due to the solubility of the salt in eighty per cent alcohol can also be greatly reduced by using ninety-five per cent alcohol4 ,the error due to the wrong factor1 based on the old atomic weight of platinum1 viz41 #j4cjef1 can be corrected by using the factor based on the recently determined atomic weight of platinum1 viz41 #aie1 which is #j4cjfhh4 #bfg4 ,differences in ,crystalline ,form4--,winton has also observed a distinct difference in the crystals of potassium platinochlorid when obtained from concentrated and dilute solutions4#baf ,when platinic chlorid is added to a concentrated solution of potassium chlorid1 a large part of the salt which is formed is precipitated in a pulverulent state1 the remainder being deposited on evaporation4 ,after treating with alcohol1 filtering1 and drying1 the double salt is found in the state of a fine powder which1 when examined under the microscope1 is found to consist largely of radiating crystals4 ,the characteristic form is one having six arms formed by the intersection1 at right angles1 of three bars4 ,numerous globular cavities in the crystals are observed in which mother liquid is enclosed4 ,for this reason the salt is not easily dried at #ajj1 but when so dried loses additional moisture at #acj1 and still more at #afj4 ,the total additional loss1 after drying at #ajj1 from this cause may amount to as much as six-tenths per cent of potassium chlorid4 ,when1 however1 the solution of the potassium salt is so dilute that no precipitate at all is formed on the addition of platinic chlorid1 the double salt is all deposited1 as well as formed slowly1 during the evaporation and occurs exclusively as octahedra4 ,these octahedra are comparatively free of cavities1 and give up practically all their moisture when dried at #ajj4 ,a method of procedure therefore for potash determination1 based on the above principle of the addition of the reagent to dilute solutions1 and drying the double salt produced upon evaporation1 after washing with ninety-five per cent alcohol at #ajj1 and using the factor #j4cjfhh for potassium chlorid and #j4aici for potassium oxid1 gives good results and is regarded as better than any of the methods which prescribe the addition of platinic chlorid to highly concentrated potash solutions4 #bfh4 ,factors for ,potash ,estimation4--,the factor now in use by the official chemists to convert potassium platinochlorid into potash 7,k,o7 is #j4aicjh1 and for potassium chlorid #j4cjef4 ,wolfbauer gives the differences which may arise by computing the potash from its platino-double chlorid by the different values assigned to the atomic weight of platinum4#bag ,the common factor used to obtain potassium chlorid from potassium platinochlorid is based on the atomic weight #aig4ah and is derived from the formula3 #b7ci4ac #ce4df7 #adi4ah ------------------------------ ------ #j4cjeeg4 #b #ci4ac #aig4ah #f #ce4df #dhh4bj ,the variations arising from taking other assigned values for the atomic weight of platinum are shown in the following table3 ,factor for potassium ,relation to factor chlorid from #j4cjeeg in per cent ,atomic ,determined weight of or ,potassium ,potassium ,platinum4 calculated platino- ,platinum4 platino- ,platinum4 by chlorid4 chlorid4 #aig4ah ,berzelius #j4cjeeg #j4gefeh #ajj4jj #ajj4jj #aig4hh ,andrews #j4cjeag #j4gecij #ii4hf #ii4fe #aie4jf ,haberstadt #j4cjfij #j4gfdfh #ajj4dd #aja4jg ,seubert #aid4hg and ,clark #j4cjgjj #j4gfeee #ajj4dg #aja4bj ,the factor #j4cjef is regarded as the best for the computation from potassium platinochlorid and #j4geff from platinum4 ,it is also suggested that it is better to make the computation from the reduced platinum than from the double salt4 #bfi4 ,recovery of the ,platinum ,waste and ,preparation of the ,platinic ,chlorid ,solution4--7#a7 ,by ,reduction in ,alkaline ,alcohol4--,all filtrates containing platinic chlorid1 all precipitates of potassium platinochlorid and all residues of metallic platinum should be carefully preserved and the platinum recovered therefrom by the following process3 ,the platinum residues are placed in a large porcelain dish4 ,since these residues contain a large amount of alcohol they should be diluted with about one-third their volume of water1 and when boiling treated with some sodium carbonate4 ,the solid potassium platinochlorids should not be added until the liquid is boiling1 and then only little by little4 ,the heating on the water-bath is continued until the liquid floating over the platinum sponge is quite clear and only slightly yellow4 ,the liquid is then poured off and the reduced platinum purified by boiling with hydrochloric acid and water4 ,it is then dried and ignited to destroy any organic matter which may be present4 ,it is advisable to boil the finely divided platinum once with strong nitric acid1 and after this is poured off the solution of the platinum is effected in a large porcelain dish over a water-bath by adding about four times its weight of hydrochloric acid1 warming1 and adding nitric acid1 little by little4 ,after the platinum is in solution the evaporation is continued until a drop of the liquid1 removed by a glass rod1 quickly solidifies4 ,the crystalline mass which is formed on cooling is taken up with water and filtered1 and then a sufficient amount of water added so that each ten cubic centimeters will contain one gram of platinum4 ,the specific gravity of this solution is #a4ah at ordinary temperatures4 ,special care must be taken that the solution contains neither platinous chlorid nor nitrogen compounds4 ,if the first named compound be present it should be converted into platinic chlorid by treatment with fuming hydrochloric acid and a little nitric acid4 ,the last mentioned compound may be removed by evaporating successively with hydrochloric acid and water4 ,if the platinic chlorid be made from waste platinum1 the danger of contamination with iridium must be considered4 ,in such a case the platinum should be separated as ammonium platinochlorid1 which can afterwards be reduced as above indicated4 ,a convenient test of the purity of platinic chlorid solution is accomplished by the precipitation of a known weight of chemically pure potassium salt4 7#b7 ,by ,reduction in ,nascent ,hydrogen4--,the platinum residues1 filtrates containing platinum1 etc41 are collected in a large flask and evaporated in a large dish on a water-bath1 and reduced by means of zinc and hydrochloric acid to metallic platinum1 the mass being warmed until all the zinc has been dissolved4 ,the supernatant liquid standing over the spongy platinum is decanted and the spongy mass boiled twice with distilled water4 ,the spongy platinum is then brought on a filter and washed till the filtrate shows no acid reaction4 ,the filter and platinum sponge are next incinerated in a platinum dish and the residue weighed4 ,the weighed mass of pure platinum is dissolved in hydrochloric acid1 with the addition of as little nitric acid as possible1 and1 after cooling1 filtered4 ,the filtrate is afterwards evaporated in a porcelain dish on a water-bath to a sirupy consistence1 taken up with water and filtered4 ,to this filtrate enough water is now added to make the solution correspond to one gram of metallic platinum in ten cubic centimeters4 ,,the ,,estimation ,,of ,,potash ,,as ,,perchlorate4 #bgj4 ,general ,principles4--,by reason of the great cost of platinum chlorid analysts have sought for a reagent of a cheaper nature and yet capable of forming an insoluble compound with potash4 ,phosphomolybdic and perchloric acids are the reagents which have given the most promising results4#bah ,the principle of the method with the latter salt is based on the insolubility of potassium perchlorate in strong alcohol containing a little perchloric acid and the comparative easy solubility of the other bases usually associated with potassium in water4 ,the ,french chemists have stated that magnesia1 when present in considerable quantities1 interferes with the accuracy of the results4 ,since in soil analysis considerable quantities of magnesia are often found1 this base1 according to the ,french chemists1 should previously be removed when present in any considerable quantity1 by the process described in the first volume4 ,kreider1 however1 as will be seen further on1 working in the presence of magnesia1 did not notice any disturbing effects caused thereby4 ,the method is applicable to the common potash salts of the trade and with certain precautions to mixed salts4 ,as will be mentioned later on1 sulfuric acid should be previously removed and this is likely to introduce an error on account of the tendency of barium sulfate to entangle particles of potash among its molecules and thus remove them from solution4 ,the barium sulfate should be precipitated slowly and in a strongly acid 7nitric or hydrochloric7 solution4 ,the loss1 which is inevitable1 is thus reduced to a minimum and does not seriously affect the value of the numbers found4 ,it is important to have an abundant supply of pure perchloric acid1 and as this is not readily obtainable in the market the best methods of preparing it are given below4 ,the method1 while it has not been worked out extensively1 is one of merit1 and seemingly is worthy of fair trial by analysts4 ,the process is by no means a new one1 but it will not be necessary to describe here its development any further than to refer to the methods proposed by ,serullas1#bai ,schlsing1#bbj ,kraut1#bba and ,bertrand1#bbb ,the method was fully developed by a committee appointed by the ,french agricultural chemists in #ahhg4bbc ,wense has also described an improved method of estimating potash as perchlorate after the removal of sulfuric acid and also a process of preparing perchloric acid by distilling potassium perchlorate with sulfuric acid in a vacuum4#bbd ,he was also the first who proposed the plan of rendering potassium perchlorate insoluble in alcohol by dissolving a little perchloric acid therein4#bbe ,the best approved methods now known of preparing the perchloric acid and conducting the analysis will be described in the following paragraphs4 #bga4 ,caspari's ,method for ,preparing ,perchloric ,acid4--,a hessian crucible about fifteen centimeters high is filled with moderately well compressed pure potassium chlorate and gradually heated in a suitable furnace until the contents become fluid4#bbf ,the heat must then be carefully regulated to avoid loss by foaming due to the evolution of oxygen4 ,the heat is continued until oxygen is no longer given off and the surface of the liquid becomes encrusted1 which will take place in from one and a half to two hours4 ,after cooling1 the contents of the crucible are pulverized and heated1 with vigorous stirring1 to boiling1 with one and a half times their weight of water4 ,by this process the potassium chlorid which has formed during the first reaction is dissolved and is thus removed4 ,the residual salt is washed with additional quantities of cold water and finally dried4 ,to remove the potassium salt from the crude potassium perchlorate obtained as above1 recourse is had to hydrofluosilicic acid4 ,the reaction is represented by the following formula3 #b,k,cl,o ,h,si,f ,k,si,f ,h,cl,o4 ,in order to effect this decomposition the potassium perchlorate is dissolved in seven times its weight of hot water and an excess of hydrofluosilicic added to the boiling solution4 ,the boiling is continued for about an hour until particles of potassium perchlorate can no longer be detected with addition of water to compensate for evaporation4 ,on cooling the gelatinous potassium silicofluorid is deposited and the perchloric acid separated therefrom as completely as possible by decantation4 ,the residue is again boiled with water and a little hydrofluosilicic acid and the clear liquor thus obtained added to the first lot4 ,finally1 any residual perchloric acid may be removed on an asbestos felt under pressure4 ,the clear liquid thus obtained is evaporated on a steam-bath to the greatest possible degree of concentration and allowed to stand in a cool place for twenty-four hours1 whereby is effected the separation of any remaining potassium silicofluorid or potassium perchlorate4 ,the residual liquid when filtered through an asbestos felt should give a perfectly clear filtrate4 ,in order to throw out the last traces of hydrofluosilicic acid and any sulfuric acid present an equal volume of water is added1 and while cold small quantities of barium chlorid are successively added until the barium salt is present in a very slight excess4 ,the clear supernatant liquid is poured off after a few hours and evaporated until the hydrochloric acid is all expelled and white fumes of perchloric acid are noticed4 ,any potassium perchlorate still remaining will now be separated and1 in the cold1 sodium perchlorate will also be separated in crystals4 ,the clear residue is again diluted with an equal volume of water and any barium salts present carefully removed with sulfuric acid4 ,the mass is allowed to stand for one or two days1 and is then filtered through paper and is ready for use4 ,the purity of the acid obtained depends chiefly on the purity of the hydrofluosilicic acid at first used4 ,hence to get good results this acid must be free from foreign bodies4 ,if an absolutely pure product be desired the acid above obtained must be distilled in a vacuum4 #bgb4 ,method of ,kreider4--,kreider has worked out a simpler method of preparing perchloric acid which will make it easy for every analyst to make and keep a supply of this admirable yet unappreciated reagent4 ,this method is conducted as follows3#bbg ,a convenient quantity of sodium chlorate1 from #ajj to #cjj grains1 is melted in a glass retort or round-bottomed flask and gradually raised to a temperature at which oxygen is freely1 but not too rapidly evolved1 and kept at this temperature till the fused mass thickens throughout1 indicating the complete conversion of the chlorate to the chlorid and perchlorate1 which requires from one and one-half to two hours3 or the retort may be connected with a gasometer and the end of the reaction determined by the volume of oxygen expelled1 according to the equation #b,n,a,cl,o ,n,a,cl ,n,a,cl,o ,o4 ,the product thus obtained is washed from the retort to a capacious evaporating dish where it is treated with sufficient hydrochloric acid to effect the complete reduction of the residual chlorate1 which1 if the ignition has been carefully conducted with well distributed heat1 will be present in but small amount4 ,it is then evaporated to dryness on the steam-bath1 or more quickly over a direct flame1 and with but little attention until a point near to dryness has been reached1 when stirring will be found of great advantage in facilitating the volatilization of the remaining liquid and in breaking up the mass of salt4 ,otherwise the perchlorate seems to solidify with a certain amount of water and its removal from the dish1 without moistening and reheating1 is impossible4 ,after triturating the residue1 easily accomplished in a porcelain mortar1 an excess of the strongest hydrochloric acid is added to the dry salt1 preferably in a tall beaker where there is less surface for the escape of hydrochloric acid and from which the acid can be decanted without disturbing the precipitated chlorid4 ,if the salt has been reduced to a very fine powder1 by stirring energetically for a minute1 the hydrochloric acid will set free the perchloric acid and precipitate the sodium as chlorid1 which in a few minutes settles1 leaving a clear solution of the perchloric acid with the excess of hydrochloric acid4 ,the clear supernatant liquid is then decanted upon a gooch1 through which it may be rapidly drawn with the aid of suction1 and the residue retreated with the strongest hydrochloric acid1 settled1 and again decanted1 the salt being finally brought upon the filter where it is washed with a little strong hydrochloric acid4 ,a large platinum cone will be found more convenient than the crucible1 because of its greater capacity and filtering surface4 ,when the filter will not hold all the sodium chlorid1 the latter1 after washing1 may be removed by water or by mechanical means1 with precautions not to disturb the felt1 which is then ready for the remainder4 ,of course1 if water is used1 the felt had better be washed with a little strong hydrochloric acid before receiving another portion of the salt4 ,this residue will be found to contain only an inconsiderable amount of perchlorate1 when tested by first heating to expel the free acid and then treating the dry and powdered residue with ninety-seven per cent alcohol1 which dissolves the perchlorate of sodium but has little soluble effect on the chlorid4 ,the filtrate1 containing the perchloric acid with the excess of hydrochloric acid and the small per cent of sodium chlorid which is soluble in the latter1 is then evaporated over the steam-bath till all hydrochloric acid is expelled and the heavy white fumes of perchloric acid appear1 when it is ready for use in potassium determinations4 ,evidently the acid will not be chemically pure because the sodium chlorid is not absolutely insoluble in hydrochloric acid2 but a portion tested with silver nitrate will prove that the sodium1 together with any other bases which may have gone through the filter1 has been completely converted into perchlorate1 and unless the original chlorate contained some potassium or on evaporation the acid was exposed to the fumes of ammonia1 the residue of the evaporation of a portion is easily and completely soluble in ninety-seven per cent alcohol and its presence is therefore unobjectionable4 ,one cubic centimeter of the acid thus obtained gives on evaporation a residue of only #j4jcf gram1 which is completely soluble in ninety-seven per cent alcohol4 ,caspari's acid under similar treatment gave a residue in one case of #j4jbd gram and in another #j4jdg gram4 ,if1 however1 a portion of pure acid be required1 it may be obtained by distilling this product under diminished pressure and1 as ,caspari has shown1 without great loss providing the heat is regulated according to the fumes in the distilling flask4 ,some modification of the above treatment will be found necessary in case the sodium chlorate contains any potassium as an impurity1 or if the latter has been introduced from the vessel in which the fusion was made4 ,in these circumstances the hydrochloric acid would not suffice for the removal of potassium1 since a trace might also go over with the sodium and thus on evaporation a residue insoluble in ninety-seven per cent alcohol be obtained4 ,to avoid this difficulty1 the mixture of sodium perchlorate and chlorid1 after treating with hydrochloric acid for the reduction of the residual chlorate1 being reduced to a fine powder1 is well digested with ninety-seven per cent alcohol1 which dissolves the sodium perchlorate but leaves the chlorid1 as well as any potassium salt insoluble4 ,by giving the alcohol time to become saturated1 which was facilitated by stirring1 it was found on filtering and evaporating that an average of about two-tenths of a gram of sodium perchlorate are obtained for every cubic centimeter of alcohol and that the product thus obtained is comparatively free of chlorids1 until the perchlorate is nearly all removed1 when more of the chlorid seems to dissolve4 ,this treatment with alcohol is continued until on evaporation of a small portion of the latest filtrate1 only a small residue is found4 ,the alcoholic solution of the perchlorate is then distilled from a large flask until the perchlorate begins to crystallize1 when the heat is removed and the contents quickly emptied into an evaporating dish1 the same liquid being used to wash out the remaining portions of the salt4 ,when the distillation is terminated at the point indicated1 the distillate will contain most of the alcohol employed1 but in a somewhat stronger solution1 so that it requires only diluting to ninety-seven per cent to fit it for use in future preparations4 ,the salt is then evaporated to dryness on the steam-bath and subsequently treated with strong hydrochloric acid for the separation of the perchloric acid4 ,one cubic centimeter of the acid prepared in this way1 on evaporation gave a residue in one case of #j4jcfi gram1 and in another #j4jcjg gram1 completely soluble in ninety-seven per cent alcohol1 which was then ignited and the chlorin determined by silver from which the equivalent of perchloric acid in the form of salts was calculated as #j4jcje gram4 ,by neutralizing the acid with sodium carbonate1 evaporating1 igniting in an atmosphere of carbon dioxid till decomposition was complete1 collecting the oxygen over caustic potash1 allowing it to act on hydriodic acid by intervention of nitric oxid1 according to a process soon to be published1 titrating the iodin liberated1 with standard arsenic and calculating the equivalent of perchloric acid1 after subtracting the amount of acid found in the form of salts1 the amount of free acid per cubic centimeter proved to be #j4ihca gram4 ,the whole process1 even when the separation with alcohol is necessary1 can not well require more than two days and during the greater part of that time the work proceeds without attention4 #bgc4 ,keeping ,properties of ,perchloric ,acid4--,by most authorities it is asserted that perchloric acid is a very unstable body and is liable to decompose with explosive violence even when kept in the dark4 ,it is probable that this tendency to spontaneous decomposition has been exaggerated4 ,it is not even mentioned in ,gmelin's ,handbook4#bbh ,the most concentrated aqueous acid has a specific gravity of #a4fe1 is colorless1 fumes slightly when exposed to the air1 and boils at #bjj4 ,it has no odor1 possesses an oily consistence and has a strong and agreeably acid taste4 ,it reddens litmus without bleaching it and is slowly volatilized at #ach without decomposition4 ,it is unaffected by exposure to the light1 even the sun's rays4 ,it is not decomposed by hydrosulfuric1 sulfurous1 or hydrochloric acids1 nor by alcohol4 ,paper saturated with the strong acid does not take fire spontaneously1 but it deflagrates with red-hot charcoal4 ,the acid prepared by the method of ,kreider has approximately the composition of the di-hydrate1 ,h,cl,o#b;,h,o4#bbi ,unless well evaporated1 however1 it is a little more dilute than is shown by the above formula4 ,the di-hydrate is quite stable and the more dilute acid can be kept for an indefinite time4 ,kreider has kept the acid for six months and noticed no change whatever in its composition4 ,acid containing one gram of perchloric acid in a cubic centimeter has been kept three months with perfect safety4 ,there is no reason why the strong aqueous acid should not be made a regular article of commerce by dealers in chemical supplies1 under proper restrictions for storage and transportation4 ,the strong acid made in this laboratory by the ,kreider method has not given the least indication of easy or spontaneous decomposition4 #bgd4 ,the ,analytical ,process4--,the perchlorate process cannot be applied in the presence of sulfuric acid or dissolved sulfates4 ,this acid1 when present1 is to be removed by the usual methods before applying the perchloric acid4 ,phosphoric acid may be present1 but in this case a considerable excess of the reagent must be used4 ,the process1 as originally proposed by ,caspari and carried out by ,kreider1 is as follows3#bcj ,the substance1 free from sulfuric acid1 is evaporated for the expulsion of free hydrochloric acid1 the residue stirred with twenty cubic centimeters of hot water and then treated with perchloric acid1 in quantity not less than one and one-half times that required by the bases present1 when it is evaporated1 with frequent stirring1 to a thick1 sirup-like consistency1 again dissolved in hot water and evaporated1 with continued stirring1 till all hydrochloric acid has been expelled and the fumes of perchloric acid appear4 ,further loss of perchloric acid is to be compensated for by addition of more4 ,the cold mass is then well stirred with about twenty cubic centimeters of wash alcohol--ninety-seven per cent alcohol containing two-tenths per cent by weight of pure perchloric acid1 with precautions against reducing the potassium perchlorate crystals to too fine a powder4 ,after settling1 the alcohol is decanted on the asbestos filter and the residue similarly treated with about the same amount of wash alcohol1 settled1 and again decanted4 ,the residual salt is then deprived of alcohol by gently heating1 dissolved in ten cubic centimeters of hot water and a little perchloric acid1 when it is evaporated once more1 with stirring1 until fumes of perchloric acid rise4 ,it is then washed with one cubic centimeter of wash alcohol1 transferred to the asbestos1 preferably by a policeman to avoid excessive use of alcohol1 and covered finally with pure alcohol2 the whole wash process requiring from about fifty to seventy cubic centimeters of alcohol4 ,it is then dried at about #acj and weighed4 ,the substitution of a gooch for the truncated pipette employed by ,caspari will be found advantageous2 and asbestos capable of forming a close1 compact felt should be selected1 inasmuch as the perchlorate is in part unavoidably reduced1 during the necessary stirring1 to so fine a condition that it tends to run through the filter when under pressure4 ,a special felt of an excellent quality of asbestos was prepared for the determinations given below and seemed to hold the finer particles of the perchlorate very satisfactorily4 ,a number of determinations made of potassium1 unmixed with other bases or non-volatile acids1 is recorded in the following table3 ,potassium ,potassium ,error on ,error on chlorid ,volume of perchlorate potassium potassium ,error on taken4 filtrate4 found4 perchlorate4 chlorid4 potash4 ,cubic ,grams4 centimeters4 ,grams4 ,grams4 ,grams4 ,grams4 #j4ajjj #ed #j4ahea #j4jjjh-- #j4jjjd-- #j4jjjc-- #j4ajjj #eh #j4ahed #j4jjje-- #j4jjjb-- #j4jjjb-- #j4ajjj #ea #j4ahei #j4jjjj #j4jjjj #j4jjjj #j4ajjj #ej #j4ahed #j4jjje-- #j4jjjb-- #j4jjjb-- #j4ajjj #dh #j4ahei #j4jjjj #j4jjjj #j4jjjj #j4ajjj #eb #j4ahed #j4jjje-- #j4jjjb-- #j4jjjb-- ,considerable difficulty1 however1 was experienced in obtaining satisfactory determinations of potassium associated with sulfuric and phosphoric acids4 ,as ,caspari has pointed out1 the sulfuric acid must be removed by precipitation as barium sulfate before the treatment with perchloric acid is attempted1 and unless the precipitation is made in a strongly acid solution1 some potassium is carried down with the barium4 ,phosphoric acid need not be previously removed1 but to secure a nearly complete separation of this acid from the potassium1 a considerable excess of perchloric acid should be left upon the potassium perchlorate before it is treated with the alcohol4 ,when these conditions are carefully complied with1 fairly good results may justly be expected4 ,below is given a number of the results obtained3 7,a7 ,volume of filtrate4 ,cubic centimeters4 7,b7 ,potassium perchlorate found4 7,c7 ,error on potassium perchlorate4 7,d7 ,error on potassium chlorid4 7,e7 ,error on potassium potash4 ,compounds taken4 7,a7 7,b7 7,c7 7,d7 7,e7 ,grams4 ,grams4 ,grams4 ,grams4 ,grams4 ,potassium chlorid #j4aj ,calcium carbonate #j4ac #ej #j4ahhg #j4jjbg #j4jjad #j4jjjebca ,magnesium sulfate #j4ac #hb #j4ahge #j4jjaf #j4jjjh #j4jjjebcb ,ferric chlorid #j4je #hj #j4ahfa #j4jjjb #j4jjja #j4jjjabcc ,magnesium sulfate #j4je #hj #j4ahdc #j4jjaf- #j4jjjh- #j4jjje-bcd ,manganese dioxid #j4je #ib #j4ahci #j4jjbj- #j4jjaj- #j4jjjf-bce ,sodium phosphate #j4dj #fj #j4ahed #j4jjje- #j4jjjb- #j4jjjb-bcf ,in the last three experiments of the above table the amount of perchloric acid was about three times that required to unite with the bases present1 and the phosphoric acid subsequently found with the potassium was hardly enough to appreciably affect the weight1 although its absolute removal was found impossible4 ,that the magnesia does not produce any disturbing effect1 as is supposed by the ,french chemists1 ,kreider has proved by the following test3 ,one hundred and fifty milligrams of magnesium carbonate were treated with perchloric acid1 evaporated till fumes of perchloric acid appeared1 and cooled1 when the magnesium perchlorate crystallized3 ,but on treating it with about fifteen cubic centimeters of ninety-seven per cent alcohol containing two-tenths per cent of perchloric acid a perfectly clear solution was obtained4 ,if1 therefore1 a sufficient excess of acid be used1 no interference will be caused by the presence of magnesium4 ,while it is true1 therefore1 that the potassium perchlorate obtained may be contaminated with a trace of phosphoric acid1 if the latter be present in large quantity1 no fear of contamination with magnesia need be entertained if a sufficient quantity of the perchloric acid be used4 #bge4 ,removal of the ,sulfuric ,acid4--,the practical objection to the removal of the sulfuric acid in the form of barium sulfate rests on the fact of the mechanical entanglement of some of the potash in the barium salt4 ,unless special precautions are taken1 therefore1 a considerable amount of the potash will be found with the barium sulfate4 ,caspari has succeeded in reducing this amount to a minimum by the following procedure3#bcg ,the solution of barium chlorid is prepared by dissolving #abg grams of crystallized barium chlorid in water1 adding #abe cubic centimeters of thirty-five per cent hydrochloric acid1 and bringing the total volume up to one liter with water4 ,five grams of the substance from which the sulfuric acid is to be removed are boiled with #aej cubic centimeters of water and twenty of strong hydrochloric acid4 ,while the solution is still in ebullition it is treated1 drop by drop with constant stirring1 with the barium chlorid solution above mentioned1 until a slight excess is added4 ,this excess does not cause any inconvenience subsequently4 ,after the precipitation is complete the boiling is continued for a few minutes1 the mixture cooled and made up to a quarter of a liter with water4 ,no account is taken of the volume of the barium sulfate formed since1 even with the precautions mentioned1 a little potassium is thrown down and the volume of the barium sulfate tends to correct this error4 ,with a solution from which the sulfuric acid had been removed as above indicated1 ,caspari found a loss of only one milligram of potassium perchlorate in a precipitate weighing over #hjj milligrams4 #bgf4 ,applicability of the ,process4--,experience has shown that sulfuric acid is the only substance which need be removed from ordinary fertilizers preparatory to the estimation of the potash by means of perchloric acid4 ,the fact that this process can be used in the presence of phosphoric acid is a matter of great importance in the estimation of potash in fertilizers1 inasmuch as these fertilizers nearly always contain that acid4 ,the fact that the ,french chemists noticed that magnesia was a disturbing element in the process1 as has been indicated in volume first1 probably arose from its presence as sulfate4 ,neither ,caspari nor ,kreider has noticed any disturbance in the results which can be traced to the presence of magnesia as a base4 ,if ammonia be present1 however1 there is a tendency to the production of ammonium perchlorate which is somewhat insoluble in the alcohol wash used4 ,solutions therefore containing ammonia before treating by the perchlorate method for potash should be rendered alkaline by soda-lye and boiled4 ,with the precautions above mentioned1 the method promises to prove of great value in agricultural analysis1 effecting both a saving of time and expense in potash determinations4 #bgg4 ,accuracy of the ,process4--,the perchlorate was tried in conjunction with the platinum method on the two samples of potash fertilizer prepared and distributed by the official reporter on potash for #ahic4bch ,one of the samples was of a fertilizer which had been compounded for the ,florida trade and contained bone1 dried blood1 and potash1 mostly in the form of sulfate4 ,the other sample consisted of mixed potash salts1 sulfate1 chlorid1 double salt1 kainit1 and about five per cent of the triple sulfate of calcium1 potassium1 and magnesium4 ,the results obtained by ,wagner and ,caspari on the two samples follow3 ,sample ,no4 #a4 ,sample ,no4 #b4 ,per cent potash4 ,per cent potash4 ,by the platinum method #ac4be #cg4ih ,by the perchlorate method #ac4ji #cg4hb ,the perchlorate method on the whole appears to be quite as accurate as the platinum process1 requires less manipulation and can be completed in a shorter time and at less expense for reagents4 ,,authorities ,,cited ,,in ,,part ,,third4 #ahe ,connecticut ,agricultural ,experiment ,station1 ,bulletin ,no4 #ig1 p4 #g4 #ahf ,annual ,report ,connecticut ,station1 #ahib1 p4 #cb4 #ahg ,colorado ,agricultural ,experiment ,station1 ,bulletin ,no4 #aj4 #ahh ,connecticut ,agricultural ,experiment ,station1 ,bulletin ,no4 #ajc1 p4 #i4 #ahi ,annual ,report1 ,massachusetts ,agricultural ,experiment ,station1 #ahhh1 p4 #bjb4 #aij ,vid4 op4 cit4 #b1 #ahij1 p4 #aaj4 #aia ,trait de la ,fabrication de ,sucre1 ,horsin-,don1 p4 #eaa4 #aib ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #cg1 p4 #cej4 #aic ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #hf4 #aid ,volume ,first1 pp4 #ai1 et seq4 #aie ,precht3 ,die ,stassfurter ,kalisalze4 #aif ,maercker3 ,die ,kalidngung1 ,s4 #a4 #aig ,vid4 op4 cit4 supra1 p4 #c4 #aih ,vid4 op4 cit4 #ab1 p4 #e4 #aii ,vid4 op4 cit4 #ab1 p4 #g4 #bjj ,volume ,first1 pp4 #cgh1 et seq4 #bja ,chemical ,news1 ,vol4 #dd1 pp4 #gg1 #hf1 #ig1 and #abi4 #bjb ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #g1 p4 #ch4 #bjc ,vid4 supra1 ,bulletin ,no4 #dc1 p4 #cdi4 #bjd ,die ,agricultur-,chemische ,versuchs-,station1 ,halle a_/,s41 ,s4 #gf4 #bje ,methoden van onderzock aan de ,rijkslandbouw-proefstations1 #ahic1 p4 #g4 #bjf ,from the ,official ,swedish ,methods4 ,translated for the ,author by ,f4 ,w4 ,woll4 #bjg ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #ce1 p4 #fc4 #bjh ,chemiker ,zeitung1 ,band #ah1 ,s4 #acbj4 #bji ,journal of the ,american ,chemical ,society1 ,vol4 #ag1 p4 #he4 #baj ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #dc1 p4 #bf4 #baa ,vid4 op4 cit4 #be1 ,vol4 #ag1 p4 #df4 #bab ,zeitschrift fr angewandte ,chemie1 #ahia1 ,s4 #bha4 #bac ,zeitschrift fr analytische ,chemie1 ,band #cb1 ,s4 #ahd4 #bad ,vid4 op4 cit4 #be1 ,vol4 #af1 p4 #cfd4 #bae ,vid4 op4 cit4 #be1 ,vol4 #ag1 p4 #dfc4 #baf ,vid4 op4 et4 loc4 cit4 supra4 #bag ,chemiker ,zeitung1 #ahij1 ,s4 #abdf4 #bah ,volume ,first1 pp4 #cfi1 #cge4 #bai ,annales de ,chimie et de ,physique #b1 ,tome #df1 p4 #bid4 #bbj ,comptes rendus1 ,tome #gc1 p4 #abif4 #bba ,zeitschrift fr analytische ,chemie1 ,band #ad1 ,s4 #aeb4 #bbb ,chemical ,news1 ,vol4 #dd1 p4 #caf4 #bbc ,rapport adress par la ,comit des ,stations ,agronomiques1 #ahhg1 p4 #aj4 #bbd ,zeitschrift fr angewandte ,chemie1 #ahia1 ,s4 #fia4 #bbe ,vid4 op4 cit4 supra1 #ahib1 ,s4 #bcc4 #bbf ,vid4 op4 cit4 #dj1 #ahic1 ,s4 #fh4 #bbg ,american ,journal of ,science1 ,june1 #ahie1 from advance proofs sent by author4 #bbh ,watt's ,translation1 ,vol4 #b1 pp4 #cag-cah4 #bbi ,manuscript communication from ,mr4 ,kreider4 #bcj ,vid4 op4 et loc4 cit4 #dc4 #bca ,the residue showed phosphoric acid plainly when tested4 #bcb ,the residue showed phosphoric acid plainly when tested4 #bcc ,only traces of phosphoric acid found in the residue4 #bcd ,only traces of phosphoric acid found in the residue4 #bce ,only traces of phosphoric acid found in the residue4 #bcf ,only traces of phosphoric acid found in the residue4 #bcg ,zeitschrift fr angewandte ,chemie1 #ahic1 ,s4 #gc4 #bch ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 ,bulletin ,no4 #ch1 p4 #eg4 ,,part ,,fourth4 ,,miscellaneous ,,fertilizers4 #bgh4 ,classification4--,nitrogen1 phosphoric acid1 and potash are the most important of the plant foods both from a commercial and physiological point of view4 ,they are the chief constituents of the most important fertilizers and manures1 but are by no means the sole essential elements of plant nutrition4 ,lime1 magnesia1 soda1 sulfur1 chlorin1 and many other elements are found constantly in plants and must be regarded as normal constituents thereof4 ,it is the purpose here1 however1 to speak only of those substances which are used as fertilizers and which constantly or occasionally are subjected to chemical examination for determining their commercial or agronomic value4 ,these bodies may be conveniently divided into two classes2 viz41 mineral and organic4 ,among those of mineral nature may be mentioned lime1 gypsum1 marls1 wood-ashes1 common salt1 and ferrous sulfate2 among those of organic nature may be included guano1 hen manure1 stall manure1 composts1 and muck4 #bgi4 ,forms of ,lime4--,by the term lime is meant the product obtained by subjecting limestone or other lime carbonates to the action of heat until the carbon dioxid contained therein is expelled4 ,the resulting lime1 ,ca,o1 when exposed for some time to the air1 or at once on the addition of water1 is converted into the hydrate ,ca,o,h1 known as slaked lime4 ,on longer exposure to the air1 the hydrate gradually absorbs carbon dioxid and becomes converted into carbonate4 ,in whatever form1 therefore1 lime is applied to the soil1 it is found in the end1 as carbonate4 ,a distinction should also be made between lime obtained from mineral substances and that got from organic products such as shells4 ,strictly speaking this is not a definite matter1 inasmuch as limestones are sometimes but little more than aggregations of fossil shells4 ,practically1 however1 the distinction is made1 and some farmers prefer shell lime to that of any other kind4 ,gas lime1 that is lime which has been used for the purification of illuminating gas made from coal1 is hardly to be considered in this connection1 since it may contain very little even of the hydrate4 ,in this case the lime has been converted largely into carbonate and sulfid4 #bhj4 ,application of ,lime4--,for many reasons it is important that the lime be transported to the field before it has had time to be converted into hydrate4 ,the transportation costs less in this state and it can be handled with far less inconvenience than when slaked4 ,the lime should be placed in small piles and left thus1 best covered with a little earth1 until thoroughly slaked4 ,it is then spread evenly over the surface4 ,the quantity used per acre depends largely on the nature of the soil4 ,stiff clays and sour marsh lands require a larger dressing than loams or well aerated soils4 ,from three to six thousand pounds per acre are the quantities usually employed4 ,when the lime is once thoroughly incorporated in the soil it is rapidly converted into carbonate1 but while in the caustic state it may act vigorously in promoting the decay of organic matter and may prove injurious in promoting the decomposition of ammonium salts with attendant loss of nitrogen4 #bha4 ,action of ,lime4--,the benefits arising from the application of lime to agricultural lands1 although in many cases great1 do not arise from any distinct fertilizing action of its own4 ,plants need lime for growth and need plenty of it1 but as a rule any soil which is good enough to grow crops will contain enough lime to furnish that constituent of the crops for many years4 ,its action is both mechanical and chemical4 ,by virtue of the latter property it renders available for plant food bodies already existing in the soil but existing in such shape as to be unavailable for plants4 ,the supply of plant food available for the crops of one year is increased but this increase is at the expense of the following years4 ,lime is a stimulant4 ,there is an ,european proverb that 8lime enriches the father but beggars the son40 ,nevertheless1 a limestone country is usually a fertile one and soils containing plenty of lime naturally1 are nearly always rich soils4 ,it is said that the trees and plants which farmers pick out as indicative of rich land are nearly always those which prefer lime soils4 ,the mechanical action of lime on soils tends to lighten heavy clays and loams and to render firmer and more consistent the light and shifting sandy soils4 ,when a lump of clay is stirred up in a bucket of rain water the water becomes muddy and remains that way for many days4 ,if1 however1 to the bucket of muddy water a little lime water be added the suspended particles of clay begin to flocculate and soon the water is clear and the clay falls to the bottom1 nor does it again make the water muddy for a long time when stirred up with it4 ,the flocky character of the precipitate is tenaciously retained and it is necessary to knead the clay for some time to induce it to reassume its original heavy character4 ,an action like this takes place when lime is added to heavy soils so that the soil becomes more porous and assumes a better tilth on plowing4 ,with sandy soils an altogether different action takes place4 ,in making mortar1 as is well known1 sand is stirred in with milk of lime and after being exposed to air for a while the mixture becomes hard and firm1 the firmness increasing with age4 ,this is due to the fact that when the mortar dries the lime begins to absorb carbon dioxid from the air and is converted into grains of carbonate which adhere strongly to neighboring sand grains and to each other so that the whole soon gets to be a solid mass4 ,something like this takes place in the soil and the sand grains are to some extent bound together4 ,the increased firmness of the soil thus gained is often of considerable advantage4 ,besides these actions1 which are more or less mechanical1 lime exerts a chemical action on many soil constituents4 ,feldspar and other common rocks contain potash1 and this potash is in such a form as to be inaccessible to plants4 ,these rocks exist in the shape of small particles in many soils and on them lime exerts a decomposing action1 setting the potash free4 ,lime also hastens the decomposition of the nitrogenous organic matter and at the same time renders the soil more retentive of the products formed4 ,the conversion of ammonia1 resulting from the decomposition of such organic matter into nitrites and nitrates1 is not easily accomplished without a proper amount of calcium carbonate4 ,the microorganisms producing this change1 which is known as nitrification1 apparently require its presence for neutralizing the acid formed4 ,in general1 it may be said that the presence of lime hastens the putrefactive process4 ,this is the reason it is so largely used in making composts4 ,it is difficult to say just what soils will be improved by liming and what will not1 and it is a matter which must be settled by experiment in each case4 ,as a rule heavy clays and loams are benefited1 yet of two such soils1 apparently identical1 one may not be affected in any marked degree while the other may readily respond to treatment4 ,sandy soils are often improved but sometimes not4 ,sour1 boggy lands1 are usually improved by the addition of enough lime to neutralize their undue acidity4 ,marsh grasses and plants are more tolerant of acid in the soil than tame grasses are1 so that in unlimed soil the former run out the latter4 ,the application of lime alone to a very poor soil does not pay4 ,the particles of lime resting in the soil are partially dissolved by the next rainfall after application1 or by the soil moisture1 forming lime water1 and the lime is distributed in this form through the soil to some extent4 ,it all probably soon becomes converted into carbonate as ground air is usually quite rich in carbon dioxid4 ,indeed1 for many soils1 it is immaterial whether lime be applied as lime or as carbonate1 granting1 of course1 that the latter be ground to a fine powder4 ,economy is in favor of the lime1 however1 not only because it needs no grinding1 but because it is lighter than the corresponding amount of carbonate1 making a saving in transportation4 ,the difference is quite considerable1 fifty-six pounds of lime being equivalent in effect to #ajj pounds of carbonate4 ,for these reasons as well as because it possesses some valuable properties not shared by the carbonate1 it is possible that for most localities lime is to be preferred to any form of ground oyster shells1 ground limestone1 marble dust or the like4 ,one of these valuable properties not possessed by limestone1 is said to be that of acting as a fungicide and insecticide4 ,as a rule1 fungi prefer acid reaction in the substances in which they grow1 so that the strongly alkaline properties of lime may make a limed soil unsuitable for their growth4#bci #bhb4 ,analysis of ,lime4--,lime1 which is prepared for use as a fertilizer1 is rarely submitted to a chemical examination4 ,it is easy to see1 however1 that such an examination is of some importance4 ,if the real value of a sample be dependent on the content of lime1 the actual quantity present as determined by analysis1 must fix the value for agricultural purposes4 ,the more important things to be determined are the quantities of lime1 and of slaked lime1 of undecomposed calcium carbonate1 and of insoluble matter4 ,it will be also of interest to determine the respective quantities of lime present as oxid1 hydrate1 and carbonate4 ,if any question be raised in the case of slaked lime in respect of its origin1 it can usually be answered by an examination of the unburned or unslaked residues4 ,in perfectly slaked lime containing no dbris1 the analyst will be unable to discover whether it has been made from limestone1 marble or shells4 ,the lime used for agricultural purposes should be reasonably free of magnesia1 and should not be air-slaked before transportation to the field4 ,in dry air-slaking1 a considerable quantity of carbonate may be formed4 #bhc4 ,the ,process4--7#a7 ,insoluble and ,soluble ,constituents4--,a representative sample of the lime having been secured1 it is reduced to a powder and passed through a half millimeter mesh sieve or ground to a fine powder in an agate mortar4 ,digest two grams of this sample with an excess of hydrochloric acid1 for two hours with frequent stirring2 filter1 wash the residue with hot distilled water until chlorin is all removed1 and dry to constant weight4 ,the lime1 magnesia1 silica1 and other constituents of the filtrate1 are determined by the usual processes of mineral analysis4#bdj 7#b7 ,state of ,combination of the ,lime4--,in a lime containing only small quantities of magnesia the lime carbonate may be determined by estimating the carbon dioxid by any one of the reliable processes in use4#bda ,in every case sufficient acid must be employed to combine with all the bases present4 ,tartaric or hydrochloric acid may be used4 ,from the volume or weight of the carbon dioxid obtained the quantity of calcium carbonate may be calculated4 ,since magnesium carbonate is more easily decomposed by heat than the corresponding calcium compound1 any residual carbonate in a well-burned sample is probably lime4 ,the total percentage of lime in the sample is to be determined in the usual way by precipitation as oxalate and weighing as carbonate or oxid4 ,the lime existing as oxid can be determined by exposing a weighed sample in an atmosphere of aqueous vapor until all the lime is slaked4 ,after drying at #ajj the increase in weight is determined and the calcium oxid calculated from the formula1 ,ca,o ,h,o ,ca,o,h4 ,if now the total lime be represented by a2 the lime combined as carbonate by b2 and that present as oxid by c2 the quantity x existing as hydrate may be calculated from the equation x a - 7b c74 ,example3 ,let the total lime be #hh per cent4 ,ca,o as carbonate1 #b 8 8 ,ca,o as oxid1 #gh 8 8 ,then the ,ca,o as hydrate #hh - 7#b #gh7 #h per cent4 ,the total lime as oxid and hydroxid may also be separated from that present as carbonate by solution in sugar4#bdb ,one gram of calcium oxid is completely soluble in #aej cubic centimeters of a ten per cent sucrose solution4 ,magnesia1 iron and alumina do not interfere with the determinations4 #bhd4 ,gypsum or ,land ,plaster4--,this substance is highly prized as a top dressing for grass and for admixture with stall manure for the purpose of fixing ammonia4 ,its value in both cases depends upon its percentage of hydrated calcium sulfate4 ,the quantity of gypsum mined in the ,united ,states in #ahic was a little over #bej1jjj tons4 ,of this amount only about #ej1jjj tons were used as fertilizer4#bdc ,in the same time there were imported into the ,united ,states1 in round numbers1 #agj1jjj tons4 ,if the same proportionate part of this were used for fertilizing purposes1 it may be said that the annual consumption of land plaster in the ,united ,states at the present time for agricultural uses is about #ge1jjj tons4 ,gypsum1 being a very soft mineral1 is easily ground and should be in the state of a fine powder when used for fertilizing purposes4 ,it is soluble in about #ejj parts of rain water1 so that when applied as a top dressing it is carried into the soil by rain4 ,its favorable action is both as a plant food and mechanically in modifying1 in an advantageous way1 the physical constituents of the soil4 ,it is also valuable for composting and for use in stables by reason of its power of fixing ammonia by the formation of lime carbonate and ammonium sulfate3 7,h,n7,,co ,ca,s,o 7,h,n7,,so ,ca,c,o4 #bhe4 ,analysis of ,gypsum4--,for agricultural purposes it will be sufficient to determine the quantity of sulfuric acid1 and to calculate therefrom the amount of calcium sulfate in the sample3 ,or the lime may be determined and the quantity of sulfate calculated therefrom4 7#a7 ,insoluble ,matter4--,in the conduct of the work the sample of gypsum is rubbed to an impalpable powder in an agate mortar4 ,the washed sample1 about one gram1 is dissolved in a large excess of dilute hydrochloric acid1 the digestion being continued at near the boiling-point1 with frequent stirring1 for at least two hours4 ,the solution is made alkaline1 filtered1 and the residue washed and dried to constant weight4 7#b7 ,sulfuric ,acid4--,the washings and filtrate from the above determination are made up to a definite volume with water and divided into two equal parts4 ,the sulfuric acid is estimated in one part by adding to it sodium carbonate until the acidity is nearly neutralized4 ,the sulfuric acid is then thrown down at near boiling temperature by the gradual addition of barium chlorid solution4 ,the barium sulfate formed is separated1 washed1 dried1 and weighed in the usual manner4 7#c7 ,iron and ,alumina4--,to the other half of the solution a little nitric acid is added and boiled to convert any ferrous into ferric iron4 ,on the addition of ammonia the iron and alumina are separated as hydroxids1 collected on a gooch1 washed1 dried1 ignited1 and weighed as oxids4 7#d7 ,in the filtrate the lime is thrown out as oxalate1 and separated and weighed in the usual way as oxid4 ,one part of ,ca,o is equal to #b4dbhf parts of ,ca,s,o4 7#e7 ,moisture4--,dry about two grams of the sample to constant weight at #hj4 7#f7 ,water of ,crystallization4--,heat the residue from the above to #aej1 until a constant weight is obtained4 ,the loss represents water of crystallization4 7#g7 ,carbonates4--,determine the quantity of carbon dioxid evolved by the usual process1 and calculate the calcium carbonate4 #bhf4 ,solution in ,sodium ,carbonate4--,gypsum is also easily decomposed by boiling with a solution of about ten times its weight of sodium carbonate4 ,the calcium1 by this operation1 is converted into carbonate and can be collected on a gooch1 washed1 and estimated as usual1 but in this case it will contain all the insoluble matters1 from which the lime can be separated by solution in hydrochloric acid4 ,in the filtrate from the above separation the excess of sodium carbonate is removed by the addition of hydrochloric to slight acidity1 and the sulfuric acid estimated as described in the preceding paragraph4 ,pure gypsum has a composition represented by the following formula3 ,ca,s,o,h,o4 ,it contains3 ,sulfur dioxid #df4ea per cent4 ,lime #cb4ef 8 8 ,water #bj4ic 8 8 ,a commercial sample of ordinary gypsum should have about the following composition3#bdd ,ca,s,o,h,o #hh4ae per cent4 ,ca,c,o #c4ej 8 8 ,fe,o and ,al,o #a4ej 8 8 ,insoluble #b4hj 8 8 ,organic matter #j4ej 8 8 ,water and undetermined #c4ee 8 8 #bhg4 ,common ,salt4--,common salt is highly esteemed in many quarters as a top dressing for lawns and meadows1 and also for cultivated crops4 ,its action is chiefly of a mechanical and katalytic nature1 since it does not form a very large percentage of the mineral food of plants4 ,on account of its affinity for moisture it is also said to have some value as a condenser and carrier of water in times of drouth4 ,on account of its great cheapness1 selling often for less than ten dollars a ton1 its use in moderate quantity entails no great expense4 ,its ability1 however1 to pay for its own use in the increased harvest is of a doubtful character when it is applied at a cost of more than a few dollars per acre4 ,in the chemical examination of a sample of common salt which is to be used as a fertilizer1 a complete analysis is rarely necessary4 ,when desired it can be conducted according to the usual methods of mineral analysis4 ,for practical purposes the moisture1 insoluble matter1 magnesia and chlorin should be determined and the quantity of sodium chlorid calculated from the latter number4 ,traces of iodin or bromin which may be present are of no consequence4 ,the moisture is determined by drying two grams of the well-mixed and finely-powdered sample to constant weight at #ajj4 ,the chlorin is obtained by precipitation of an aliquot part of a solution of the salt by set silver nitrate1 using potassium chromate as indicator4 ,in the determination of insoluble matter it should not be forgotten that a little gypsum may be present1 and this should be dissolved by rubbing to a finer powder and by repeated digestion in water4 ,the magnesia and lime are separated and determined in the usual manner4 ,if the quantity of gypsum present be sufficient to warrant it the sulfuric acid may be separated and weighed in the manner already described4 ,common salt when present in the soil in proportions greater than one-tenth per cent is injurious to vegetation4 #bhh4 ,green ,vitriol4--,when iron is used as a fertilizer it is usually applied as ferrous sulfate4 ,the value of iron in a soil is incontestable and by reason of the fact that fertile soils are always well aerated the iron present in the arable layer is found in the ferric state4 ,when green vitriol is applied to the soil it undergoes gradual oxidation and appears finally in a more highly oxidized form4 ,iron acts directly on the plant in promoting the development of the chlorophyll cells1 and is also found in almost all parts of the vegetable organism4 ,a too great quantity of ferrous sulfate is destructive of plant growth in which respect it resembles common salt4 ,it should therefore be applied with due regard to the dangers which might arise from an excessive quantity4 ,it is not likely1 however1 that when applied in a finely powdered state at the rate of from two to four hundred pounds per acre it would ever prove poisonous to vegetation4 ,in the analysis of a sample of green vitriol it will be sufficient to determine the moisture1 water of crystallization1 iron1 and sulfuric acid4 ,the moisture may be ascertained by drying the finely powdered sample over sulfuric acid for a few hours4 ,the water of crystallization is separated by exposing the sample to a temperature of #bhe for two hours4 ,the iron may be determined by oxidizing to the ferrous state by boiling with nitric acid and then precipitating with ammonia1 and proceeding as directed for iron analysis4 ,the sulfuric acid is separated as barium sulfate and determined as already directed4 #bhi4 ,stall ,manures4--,there are no definite methods to be described for the analyses of that large class of valuable fertilizer produced in the stable and pen1 and which collectively may be called stall manures4 ,the methods of sampling have already been described1#bde but only patience and tact will enable the collector to get a fair representation of the whole mass4 ,these manures are a mixture of urine1 excrement1 waste fragments of fodder1 and the bedding used for the animals4 ,with them may also be included the night soil and waste from human habitations and the garbage from cities4 ,all of these bodies contain valuable plant foods and the phosphoric acid1 potash1 and nitrogen therein are to be determined by the methods already given for these bodies when they occur in1 or are mixed with1 organic matter4 ,in general1 stall manures are found to have a higher manurial value than is indicated by the amount of phosphorus1 potash1 and nitrogen which they contain4 ,through them there is introduced into the soil large quantities of humus bodies whereby the physical state of the soil is profoundly modified and its adaptability to the growth of crops1 as a rule increased4 ,the addition of active nitrifying ferments in stall manure is also advantageous4 ,stall manures1 however1 may in many cases prove to be injurious to a crop1 as for instance1 when they are applied in a poorly decomposed state and in a season deficient in moisture4 ,it is essential therefore that the bedding of animals be in a finely divided state1 whereby not only are the absorptive powers of the organic matter increased but also the conditions for their speedy decay favored4 ,to avoid the loss of ammonia arising from decomposing urine it is advisable to compost the stall manure with gypsum or to sprinkle it from time to time with oil of vitriol4 ,in the analysis the moisture may be estimated by drying a weighed portion of the sample to constant weight at #ajj or at a lower temperature in a vacuum4 ,the potash and phosphoric acid are determined as usual1 with previous careful incineration1 and the nitrogen secured by the moist combustion process4 #bij4 ,hen ,manure4--,this fertilizing substance is a mixture of the excrement of the fowl yard with feathers1 dust1 and other dbris4 ,measured by the standard applied to commercial fertilizers hen manure has a low value4 ,as in the case of other farm manures1 however1 it produces effects quite out of proportion to the amount of ordinary plant foods which it contains4 ,in a sample examined at the ,connecticut station the percentages of fertilizing constituents were found to be the following#bdf3 ,water #ea4hd ,organic and volatile matters #bd4bg ,ash #bc4hi ,the organic matter contained #j4fa per cent of nitrogen as ammonia and the ash #j4ig per cent of phosphoric acid1 and #j4ei per cent of potash1 all calculated to the original weight of the sample4 ,the percentage of water in this sample is undoubtedly higher than the average1 so that it can hardly be taken to represent the true composition of this manure4 ,the potash1 phosphoric acid1 and nitrogen are to be determined by some one of the standard methods already described1 the two former after careful incineration4 #bia4 ,guanos and ,cave ,deposits4--,the principal constituents of value in these deposits are nitrogen and phosphoric acid4 ,the other organic matters are also of some value but have no commercial rating4 ,the nitrogen may be present in all its forms2 viz41 organic1 ammoniacal1 amid1 and nitric1 and for this reason is well suited not only to supply nourishment to the plant in the earlier stages of its growth but also to cater to its later wants4 ,in guano deposits in caves1 due usually to the presence of bats1 similar forms of fertilizers are found and the soluble constituents due to decay and nitrification are protected from the leaching to which they would be subjected in the open air4 ,in many localities in the ,united ,states these deposits are found1 but the humidity of our climate has prevented the immense open deposits of guano that characterize some of the arid islands of the ,pacific ,ocean4 ,many bat guanos examined in this laboratory have also been found to contain potash1 in one case #a4gh per cent4 ,it is suggested therefore that the analyst do not omit to examine each sample qualitatively for this substance and to determine its amount when indications point to its presence in weighable proportions4 ,in the many samples of bat guano of ,american origin which have been analyzed in this laboratory in the last few years some very rich in plant food have been found4 ,in one instance the total percentage of nitrogen present1 was #aj4aa per cent4 ,in some cases the phosphoric acid is high but rarely in conjunction with a high content of nitrogen4 ,in one instance where the total phosphoric acid reached #ad4ec per cent1 the content of nitrogen was #d4hg per cent4 ,in respect of the processes of analysis there are no especial directions to be given4 ,the phosphoric acid1 as given below1 and the potash are to be determined by the usual methods1 the total phosphoric acid and potash after the destruction of the organic matter4 ,in old cave deposits the processes of decay and nitrification seem to have long been completed and we have found very little power of inducing nitrification in culture solutions seeded from these samples4 #bib4 ,french ,official ,method for ,total ,phosphoric ,acid in ,guanos4--,to determine the phosphoric acid in guanos1 the method officially adopted by the ,french agricultural chemists may be used4#bdg ,two grams of the sample are rubbed up in a porcelain crucible with a decigram of slaked lime to prevent the possible reduction of the phosphoric acid by the organic matter4 ,the mixture is slightly moistened with a few drops of water1 dried on a sand-bath1 and afterwards heated to redness1 best in a muffle1 until organic matter is destroyed4 ,the contents of the crucible are detached and placed in a flask of #bjj cubic centimeters capacity4 ,the crucible is well digested twice with some hydrochloric acid to dissolve any adhering fragments1 and finally washed with hot water1 the acid and water being added to the flask4 ,the contents of the flask are boiled for fifteen minutes and then poured into a flat-bottomed dish1 the flask well rinsed three or four times with small quantities of water1 and the liquor and washings are evaporated to dryness to render the silica insoluble4 ,the residue is taken up by a mixture of ten cubic centimeters each of hydrochloric acid and water1 heated for a few minutes and filtered1 and the dish well washed with successive small portions of water1 but the total volume of the filtrate and washings should not exceed eighty cubic centimeters4 ,in this filtrate the phosphoric acid may be determined by any one of the approved methods4 #bic4 ,waste ,leather4--,this material belongs probably to that class of nitrogenous substances which has already been considered in paragraph #adi4 ,the chief manurial value of the waste is found in its nitrogenous content4 ,the value of this for available plant food has been investigated by ,lindsey4#bdh ,a complete resum of the literature of the subject is also given by him4 ,the best way of identifying leather waste is by the process proposed by ,dabney4#bdi ,it depends on the color produced in a solution of iron phosphate by the tannin compounds derived from the leather4 ,the reagent is prepared by dissolving a freshly made precipitate of iron phosphate from ten grams of ferric chlorid in #djj cubic centimeters of an aqueous solution of forty grams of glacial phosphoric acid4 ,a gentle heat promotes the solution of the phosphate4 ,in the case of a fertilizer supposed to contain leather1 about one gram of the material is treated with thirty cubic centimeters of water and a few drops of sulfuric acid4 ,the mixture is boiled and poured on a filter4 ,to a portion of the filtrate some of the solution of iron phosphate is added1 and the mixture made alkaline with ammonia4 ,if leather be present in the sample1 a purple or wine color will be developed4 ,lindsey could easily detect the leather when it was added in ten per cent quantities by the above method1 and he regards this method as superior to the microscope which is unreliable in the case of finely ground material4 ,while leather1 as such1 decays slowly1 and therefore is not at once available for the nourishment of plants it acquires greater utility after digestion in sulfuric acid4 ,artificial digestion experiments with leather previously treated with sulfuric acid show that1 approximately1 seventy per cent of the nitrogen pass into solution4 ,such a prepared leather has1 therefore1 a digestive coefficient in respect of nitrogen not much inferior to most organic bodies4 ,in comparative trials with sodium nitrate it was demonstrated that nitrogen in leather1 previously dissolved in sulfuric acid1 has a rank of about sixty when it is rated at one hundred in the soda salt4 ,for the estimation of the nitrogen in leather the moist combustion process is to be preferred4 #bid4 ,analysis of ,wood ,ashes4--,the only kinds of ashes used extensively for manurial purposes are those derived from the burning of hard woods4 ,the ash of soft woods1 such as the pine1 is too poor in plant foods to warrant its transportation to any great distance for manurial purposes4 ,the methods of incineration of organic bodies for the purpose of obtaining and estimating their mineral contents will be fully discussed in the third volume of this work4 ,it is important in ash analysis to know whether there be enough of iron present to combine with all the phosphoric acid4 ,for manurial purposes it will be found sufficient to determine the percentages of potash and phosphoric acid alone4 ,for hygienic purposes it is advisable to examine the ash qualitatively and1 if necessary1 quantitatively for zinc1 lead1 copper1 boric acid1 and other bodies of a similar character which may be naturally present in the ash1 or may have been added to the organic substance from which it was prepared for preservation or other purposes4 ,the methods of making these special investigations will be discussed in the succeeding volume4 ,at present will be given1 however1 not only the methods for detecting phosphoric acid and potash1 but also for a complete analysis of an ash in so far as its usual constituents are concerned4 #bie4 ,carbon1 ,sand1 and ,silica4--,the official agricultural chemists have recommended the following procedure for the determination of the unburned carbon1 and the sand and silica4#bej ,five grams of the ash are treated in a beaker1 covered with a watch glass with fifty cubic centimeters of hydrochloric acid of #a4aae specific gravity1 and digested on the water-bath until all effervescence has ceased4 ,the cover is then removed and the liquid evaporated to complete dryness to render the silica insoluble4 ,the residue is moistened with two or three cubic centimeters of hydrochloric acid and taken up with about fifty cubic centimeters of water1 allowed to stand on the water-bath a few minutes1 filtered1 and thoroughly washed4 ,the filtrate and washings are made up to a quarter of a liter for analysis4 ,the residue is washed from the filter into a platinum dish and boiled about five minutes with twenty cubic centimeters of a saturated solution of pure sodium carbonate2 afterwards a few drops of pure sodium hydroxid solution are added and the liquid allowed to settle1 and it is then decanted through a tared gooch4 ,the residue is boiled with sodium carbonate solution and decanted as before1 a second and a third time1 and finally brought upon the felt and thoroughly washed1 first with hot water1 then with a little dilute hydrochloric acid1 and finally with hot water until free of chlorids4 ,the residue in the gooch is dried at #aaj to constant weight1 giving the carbon and sand4 ,it is then incinerated and the weight of the sand determined1 the difference giving the carbon4 ,it is advisable to examine the sand with a microscope to determine if it be pure4 ,the alkaline filtrate and washings from the carbon and sand are acidified with hydrochloric1 evaporated to dryness1 and the silica separated and determined in the usual way4 ,instead of determining soluble silica directly from the sodium carbonate solution1 as above1 another portion of the ash may be treated with hydrochloric acid and evaporated to dryness as before described1 filtered on an ordinary filter1 washed1 burned1 and weighed1 giving the weight of silica plus sand1 from which the weight of sand is deducted to obtain soluble silica4 ,it is inadmissible to separate the soluble silica from the residue after it has been ignited4 ,instead of limiting the quantity of hydrochloric acid used for moistening the dried residue1 as suggested above by the official chemists1 enough should be employed to fully saturate the mass4 ,the weight of pure ash is obtained by subtracting from the weight of the sample taken the sum of the weights of carbon1 sand1 and carbon dioxid4 #bif4 ,ferric ,phosphate and the ,alkaline ,earths4--,the ferric phosphate1 lime1 magnesia1 and manganese are determined in an aliquot part of the first hydrochloric acid solution and washings obtained above4 ,fifty or one hundred cubic centimeters may be used1 corresponding to one or two grams of the original ash4 ,the accurately measured quantity of the solution is carefully treated with ammonia until the precipitate formed on its addition becomes permanent on shaking4 ,ammonium acetate and acetic acid are then added until the mixture has assumed a strongly acid reaction4 ,the separation of the ferric phosphate precipitate is promoted by gentle warming1 and it is separated by filtration without unnecessary delay4 ,if the precipitate be not large the sample contains no manganese and alumina in weighable quantities1 and if the filtrate be not red the precipitate be washed with hot water containing a little ammonium nitrate4 ,it is then ignited and weighed as ,fe,p,o and the quantity of ferric oxid computed therefrom4 ,if1 however1 the precipitate be large it is well washed as above and then dissolved in as small a quantity as possible of hydrochloric acid1 and the solution is again precipitated as above by the addition of ammonia1 ammonium acetate1 and acetic acid4 ,the ferric phosphate obtained by the second precipitation is treated exactly as above described4 ,in case1 however1 any weighable quantities of manganese or alumina are present it will not do to weigh the precipitate of ferric phosphate directly even after a second precipitation4 ,also if the filtrate at first obtained have a red color the precipitate may contain basic ferric phosphate4 ,in this latter case it should be ignited and weighed1 then dissolved in hydrochloric acid and the ferric oxid estimated in the solution and from the difference the quantity of combined phosphoric acid calculated4 ,the separation of the iron from the phosphoric acid may be accomplished by adding tartaric acid to the hydrochloric acid solution of the iron phosphate above obtained and then ammonium chlorid and ammonia4 ,the mixture is placed in a flask and ammonium sulfid added4 ,the flask is closed1 placed in a warm place1 and allowed to stand until the supernatant liquid is clear and of a pure yellow color without a trace of green4 ,the iron is separated by filtration1 washed1 dissolved1 and estimated in the usual way4 ,if manganese and alumina be present the iron and manganese are separated from the phosphoric acid and alumina by the processes just given for the separation of iron from phosphoric acid4 ,in the filtrate the alumina and phosphoric acid are separated as follows3 ,the filtrate is evaporated in a platinum dish after the addition of an excess of pure sodium carbonate until no ammonia is set free by a further addition of the carbonate4 ,some nitric acid is then added and the evaporation continued to dryness4 ,the residue is fused and after cooling softened with water1 washed into a small beaker1 some hydrochloric acid added1 warmed1 and filtered4 ,ammonia is next added until the reaction is alkaline4 ,if no precipitate be produced no alumina is present4 ,in this case more nitric acid is added1 the solution again evaporated1 and the phosphoric acid determined by the usual methods4 ,in case a precipitate is formed1 showing the presence of alumina1 nitric acid is added until the precipitate is dissolved1 and then in slight excess and after evaporation the phosphoric acid separated by molybdic solution and determined as usual4 ,from the filtrate the excess of molybdic acid is removed by hydrogen sulfid and the alumina determined in the filtrate3 ,or the alumina may be determined directly in the hydrochloric acid solution of the melt above obtained as aluminum phosphate by adding sodium phosphate1 ammonia and acetic acid4 ,the aluminum phosphate is separated by filtration and determined in the usual manner4 ,the phosphoric acid is then determined in another aliquot part of the original filtrate from the first solution of the ash4 ,since most ashes contain an excess of phosphoric acid above the quantity required to combine with the iron it is preferable to proceed on that basis as described in the next paragraph4 #big4 ,method ,used in this ,laboratory4--,the principle of the method rests on the assumption that all the phosphoric acid may be removed from the solution by the careful addition of iron chlorid4 ,any excess of iron is then removed by ammonium acetate and the manganese1 lime1 and magnesia1 are separated in the filtrate4 ,the percentage of iron is determined by reduction of the iron in another portion of the solution and titration with potassium permanganate4 ,the process as conducted by ,mc,elroy1 is as follows3#bea ,moisture4--,if the ash contain much carbon the water is best determined by drying in vacuo to avoid oxidation4 ,sand1 ,silica1 and ,carbon4--,place a portion of the ash in a weighed platinum dish1 weigh1 and cover the sample with hydrochloric acid of #a4aae specific gravity4 ,evaporate to dryness on the water-bath1 and then heat for fifteen minutes at #aje to #aaj in an air-bath4 ,repeat the treatment with acid and drying3 ,finally cover with a third portion of acid and digest on the water-bath for an hour or two4 ,filter into a weighed gooch and wash the residue free of chlorids4 ,the gooch is best weighed with the dish to avoid the necessity of transferring the silica which may adhere to the sides of the former4 ,dry at a few degrees above the boiling temperature of water and weigh4 ,where the ash contains much charcoal the drying is best done in a vacuum at #fj to #gj4 ,the increase in weight found represents sand1 silica1 and carbon3 ,burn and reweigh4 ,the loss is carbon4 ,another portion of ash is treated as before except that it is filtered through a paper filter4 ,the filtrate is united with that of the previous sample in a graduated flask4 ,when the washing is completed the filter is placed in the dish1 a weak solution of caustic soda added1 and the mixture heated on the water-bath for some time4 ,decant while hot through a fresh filter and retreat the residue in the dish with another portion of alkali4 ,finally wash with hot water till the alkaline reaction disappears1 then with weak hydrochloric acid1 then with water until chlorids disappear4 ,the washed mass on the filter is transferred to a platinum dish and ignited4 ,the weight obtained represents sand4 ,separation of ,phosphoric ,acid4--,the united filtrates from the two determinations are placed in a graduated flask and made up to the mark4 ,an aliquot portion of this solution representing half a gram of the original ash or any other convenient quantity is transferred to a beaker and a solution of ferric chlorid added until ammonia produces a brown precipitate in the mixture4 ,neutralize with ammonia and hydrochloric acid alternately until the liquid is as little acid as it can be and still remain clear4 ,add from ten to twenty cubic centimeters of a solution of sodium acetate 7#a3aj7 and bring to a boil4 ,the liquid should be quite dilute4 ,filter and wash free of chlorids with boiling water containing some sodium acetate4 ,manganese4--,make the filtrate faintly alkaline with ammonia and add ammonium sulfid4 ,any manganese sulfid which may form is separated by filtration1 treated with dilute acetic acid and the resulting solution1 which should be clear1 heated to boiling1 nearly neutralized with caustic soda1 and mixed with bromin water4 ,the resultant manganese dioxid is to be filtered into a gooch1 ignited and weighed as ,mn,o4 ,lime4--,reacidify the filtrate from the manganese sulfid with acetic acid1 heat to boiling and add ammonium oxalate3 ,allow to stand over night1 filter through a gooch and wash with water containing acetic acid4 ,the calcium oxalate can be weighed as such1 but it is preferable to dry thoroughly and then heat in a small bunsen flame until a change can be noted passing over the precipitate4 ,if this is carefully done the residue will be calcium carbonate4 ,in any case the result is to be checked by igniting over the blast lamp to constant weight and weighing the lime thus obtained4 ,magnesia4--,in the filtrate the magnesia can be determined by sodium phosphate in the usual manner4 ,in very accurate work the calcium oxalate obtained as directed above can be dissolved and reprecipitated1 and the magnesia in the filtrate added to that in the first filtrate4 ,iron4--,for iron another aliquot portion of the original solution is taken1 acidified with sulfuric evaporated to drive off hydrochloric acid1 rediluted and passed through the ,jones reductor described in paragraph #aab4 ,the filtrate is titrated with potassium permanganate solution in the usual manner4 ,alkalies4--,for the alkalies another aliquot portion is taken and precipitated while hot1 with barium chlorid and barium hydrate1 filtered1 and ammonia and ammonium carbonate added to remove the excess of barium salt4 ,refilter1 evaporate to dryness in a platinum dish1 and ignite gently to expel all ammonia salts1 repeat this operation after taking up with water and finally heat to constant weight4 ,the weight obtained represents a mixture of potassium and sodium chlorids1 with usually carbon derived from impurities in the ammonia4 ,a little magnesia is often present4 ,the potassium is estimated by means of platinum solution1 and the potassium chlorid found deducted from the total weight gives the sodium chlorid4 ,the carbon is usually unweighable1 though it often looks as if present in considerable quantity4 ,it may be estimated1 however1 by dissolving the mixed chlorids in weak hydrochloric acid and filtering through a gooch before making the potassium estimation4 ,the estimation of the magnesia remaining with the mixed chlorids may be effected by evaporating the alcoholic solution remaining after the precipitation of the potassium to dryness1 redissolving in water1 placing the solution in a flask provided with gas tubulures1 introducing hydrogen1 and placing in the sunlight4 ,the platinum is soon reduced1 leaving the liquid colorless4 ,heating facilitates the reaction4 ,displace the hydrogen by a current of carbon dioxid1 filter1 concentrate the solution and precipitate the magnesia by sodium phosphate in the usual manner4 ,phosphoric ,acid4--,it is best to determine the phosphoric acid directly in an aliquot part of the first filtrate from the hydrochloric acid solution of the ash obtained as described under the determinations of sand1 silica and carbon4 ,when there is not enough of the material for this1 the precipitate of ferric phosphate may be dissolved and the phosphoric acid determined after separation with ammonium molybdate4 ,sulfuric ,acid4--,fifty cubic centimeters of the original hydrochloric acid filtrate1 obtained as described under the determinations of sand1 silica and carbon1 are heated to boiling1 and the sulfuric acid thrown out by the gradual addition of barium chlorid4 ,during the precipitation the mixture is kept at the boiling temperature1 but taken from the lamp and the precipitate allowed to settle from time to time until it is seen that an additional drop of the reagent causes no further precipitate4 ,the barium sulfate is collected1 dried1 and weighed in the usual manner4 ,chlorin4--,dissolve from one to five grams of the ash in nitric acid in very slight excess1 or in water4 ,if the solution be made in nitric acid the excess must be neutralized if the chlorin be determined volumetrically2 and if the solution be in water1 nitric acid must be added if the determination be gravimetric4 ,the volumetric determination is accomplished in the usual manner with a standard silver nitrate solution1 using potassium chromate as indicator4 ,the gravimetric determination is effected by precipitation with silver nitrate1 collecting1 washing1 and drying at #aej the silver chlorid obtained4 ,carbon ,dioxid4--,the carbon dioxid is most conveniently estimated in from one to five grams of the ash1 according to its richness in carbonates1 by the apparatus described in volume first1 or some similar device4#beb #bih4 ,official ,method for ,determinations of the ,alkalies4--,evaporate the filtrate and washings from the sulfuric acid determination1 paragraph #big1 in a porcelain dish to dryness1 redissolve in about fifty cubic centimeters of water and add milk of lime1 or barium hydroxid solution1 which must be perfectly free from alkalies1 until no further precipitation is produced1 and it is evident there is an excess of calcium hydroxid or barium hydroxid present2 boil for two or three minutes1 filter hot1 and wash thoroughly with boiling water1 precipitate the lime and baryta from the filtrate with ammonia and ammonium carbonate1 filter1 evaporate the filtrate to dryness in a porcelain dish1 and drive off the ammonia salts by heat below redness4#bec ,when cold1 redissolve in fifteen or twenty cubic centimeters of water1 precipitate again with a few drops of ammonia and ammonium carbonate solution1 let stand a few minutes on the water-bath and filter into a tared platinum dish and evaporate to dryness1 expel the ammonia salts by heating to just perceptible dull redness1 weigh the potassium and sodium chlorids obtained and determine the potassium chlorid with platinic chlorid as usual4 ,the potassium may also be determined by the perchlorate method1 or the total chlorin be determined volumetrically1 and the relative percentages of potassium and sodium chlorids calculated by the usual formula3 ,or multiply the weight of chlorin in the mixture by #b4ajce1 deduct from the product the total weight of the chlorids and multiply the remainder by #c4fceh4 ,the product expresses the weight of the sodium chlorid contained in the mixed salts4 ,the indirect method is only applicable when there are considerable quantities of alkalies present and where they exist in approximately molecular proportions4 ,it is therefore a process rarely to be recommended in ash analysis4 #bii4 ,statement of ,results4--,the bases which are found present in the ashes of wood and other vegetable tissues exist without doubt before incineration1 chiefly in combination with inorganic acids4 ,even the phosphorus and sulfur which after ignition appear as phosphates and sulfates1 have previous thereto existed in an organic form to a large extent4 ,the silica itself is profoundly modified in the organism of the growing plant and doubtless does not exist there in the purely mineral form in which it is found in the ash4 ,during the progress of incineration1 with proper precautions1 all the phosphorus and sulfur are oxidized and appear as phosphoric and sulfuric acids4 ,the silica is reduced to a mineral state1 and if a high heat be employed silicates are formed4 ,the organic salts of lime1 magnesia and other bases at a low temperature are converted into carbonates1 and if a higher temperature be used1 may appear as oxids4 ,the organic compounds of alkalies will be found in the ash as carbonates4 ,it would be useless1 therefore1 to try to state the results of ash analysis in forms of combination similar to those existing in the original vegetable tissues4 ,it is not certain even that we can in all cases judge of the form of combination in which the different constituents exist in the ash itself4 ,it is therefore to be preferred in a statement of ash analysis to give the bases in the form of oxids1 and the sulfur and phosphorus in the form of anhydrids1 and the chlorin in its elementary state4 ,in this case an equivalent amount of oxygen to the chlorin found must be subtracted from the total4 ,if an attempt be made to combine the acid and basic elements the chlorin should first be united with sodium1 and any excess thereof with potassium1 and the amount of base so combined calculated to oxid and deducted from the total of such base or bases present4 ,the carbonic acid present should be combined first with alkalies after the chlorin has been supplied4 ,the phosphoric acid should be combined first with the iron and afterwards with lime or magnesia4 ,in all cases the percentages should be based upon the ash1 after the carbon and sand have been deducted1 or it is also convenient at times to throw out of the results the carbon dioxid and to calculate the other constituents to the ash free of that substance4 ,in determining the quantities of mineral matters removed from soil by crops1 the ash should be determined with great care1 freed of carbon and sand1 and the calculations made on the percentage thus secured4 ,in all statements of percentages of the essential constituents of ash1 as regards fertilizing materials1 it should be specified whether the percentage is calculated on a crude ash1 the pure ash1 that is free of carbon and sand1 or upon a basis excluding the carbon dioxid4 ,for the purpose of fertilizer control1 the analyst and dealer will be satisfied1 as a rule1 with the determination of the percentages of phosphoric acid and potash alone4 ,to the other constituents of an ash is not assigned any commercial value4 ,,authorities ,,cited ,,in ,,part ,,fourth4 #bci ,compiled for author by ,mr4 ,k4 ,p4 ,mc,elroy4 #bdj ,volume ,first1 pp4 #cef et seq4 #bda ,volume ,first1 pp4 #ccg and #cij4 #bdb ,volume ,second1 p4 #ha4 #bdc ,day3 ,mineral ,resources of the ,united ,states1 #ahic1 p4 #gac4 #bdd ,frankland3 ,agricultural ,analysis1 p4 #bdj4 #bde ,volume ,second1 p4 #i4 #bdf ,annual ,report ,connecticut ,agricultural ,experiment ,station1 #ahhh1 ,part #a1 p4 #hj4 #bdg ,rapport address par le ,comt des ,stations ,agronomiques1 #ahhg1 p4 #cd4 #bdh ,agricultural ,science1 ,vol4 #h1 pp4 #b and #c1 #ahid1 and ,massachusetts ,agricultural ,station1 #abth ,annual ,report1 pp4 #bhe et seq4 #bdi ,north ,carolina ,agricultural ,experiment ,station1 ,bulletin ,no4 #c4 #bej ,bulletin ,no4 #dc1 ,chemical ,division1 ,u4 ,s4 ,department of ,agriculture1 p4 #cij4 #bea ,compiled for author by ,mr4 ,k4 ,p4 ,mc,elroy4 #beb ,volume ,first1 p4 #ccg4 #bec ,vid op4 cit4 #ab1 p4 #cia4 ,,index4 ,a ,page4 ,acid phosphates1 definition1 #aej1 #aea ,albuminoid nitrogen1 separation1 #bbe ,alkalies1 determination in ashes1 #cbj1 #cba official method for determination in ashes1 #cbb ,alkaline earths in wood ashes1 #cag ,amid nitrogen1 separation1 #bbe1 #bbh ,ammonia1 preparation for washing precipitates1 #ag ,ammoniacal nitrogen1 #aff separation1 #bbf ,ammonium citrate1 influence of acidity and alkalinity on solvent power1 #acg1 #ach movement on solvent power1 #ada quality of sample on solvent power1 #acf temperature on solvent power1 #acd time on solvent power1 #acc preparation1 #dd solvent for phosphoric acid1 #acb nitrate solution1 preparation1 #de ,animal dbris1 treatment1 #aa ,aqueous vapor1 measurement of tension1 #ahj1 #aha ,arsenic1 error1 #ed ,asboth1 method for nitrogen1 #bab ,ashes1 analysis1 statement of results1 #cbc1 #cbd composition1 #beb fertilizing value1 #bed percentage in various woods1 #bec ,authorities cited in ,part ,first1 #aef-afj ,fourth1 #cbd ,second1 #bdf1 #bdg ,third1 #cjj1 #cja ,b ,barium oxalate1 reagent for potash determination1 #bha ,barometer1 method of use1 #agh1 #agi ,basic phosphatic slags1 technical analysis1 #abc slags1 ,dutch method for analysis1 #gg ,halle method for analysis1 #gf ,berzelius1 method of estimating fluorin1 #ce1 #cf ,blood1 dried1 #afe ,brown1 separation of iron and alumina in phosphates1 #aca ,c ,calcium carbonates1 function in manufacture of superphosphates1 #aeb fluorids1 reactions1 #aeb ,carbon dioxid1 determination in ashes1 #cbb phosphates1 #ai estimation1 #ai in wood ashes1 #cae1 #cai ,carnallit1 #bfj method for analysis1 #bgd-bgg ,cave deposits1 #cab ,chatard1 modification of ,berzelius method1 #ce-cg ,glaser-,jones process1 #cj1 #ca organic matters in phosphates1 #ah ,chile saltpeter1 #afh1 #bce adulteration1 #bcd analysis1 #bcd application1 #bdj commercial forms1 #bcc consumption1 #bde ,gantter's method1 #bcf-bch method of difference1 #bci1 #bdj ,french sugar chemists1 #bcf percentage of nitrogen1 #bcc quantity applied1 #bdd zinc-iron method1 #bcd1 #bce ,chlorin1 determination in ashes1 #cbb ,chromium1 occurrence in phosphates1 #abh ,citrate and molybdate methods1 comparative accuracy1 #fi insoluble phosphoric acid1 #da method1 #eg-ei applicability1 #ade1 #adf ,swedish modification1 #ff1 #fg soluble phosphoric acid1 #dd direct precipitation1 #adg ,dutch method1 #fh ,coloration of distillate1 #ahg ,combustion furnace1 #age ,copper oxid combustion1 #agj ,cottonseed hulls and meal1 composition1 #bea ,crispo1 method of estimating iron and alumina1 #bi1 #cj ,d ,dilute ammonia1 preparation1 #de ,distillate1 coloration1 #ahg ,distillation apparatus1 #bjh ,dudley and ,pease1 determination of phosphoric acid in the presence of iron1 #aac ,f ,factors for calculating potash analysis1 #bgj phosphoric acid analysis1 #ag ,ferric phosphate in wood ashes1 #cag1 #cah ,ferrous sulfate1 analysis1 #caj1 #caa uses1 #caj ,fertilizers1 cost of transportation1 #b definition1 #a drying samples1 #ab ,german methods1 #ac official methods1 #ac natural1 #a objects of analysis1 #a sampling mixed1 #f ,french method1 #g method of ,french sugar chemists1 #g treatment of samples in laboratory1 #aj ,fertilizing ingredients1 trade values1 #c valuation1 #b materials1 minerals containing1 #e sampling organic1 #h ,fish scrap1 #acd ,fluorin1 estimation in phosphates1 #ce-ch occurrence in bones1 #acj ,g ,german experiment stations1 methods for determining phosphoric acid1 #de1 #df ,glaser method for estimating iron and alumina1 #bd1 #be1 #bg ,gooch distillation method1 #ai ,green vitriol1 analysis1 #caj1 #caa uses1 #caj ,grinding apparatus for fertilizers1 #f ,guanos1 #cab analysis1 #cac nitrogen content1 #aff origin1 #afg ,gunning method1 #baf1 #bag adapted to nitrates1 #bbj official1 #bai for nitrates1 #bbj process1 reactions1 #bah ,gypsum1 #cjg amount used1 #cjg analysis1 #cjh1 #cji use for composting1 #cjg1 #cjh ,h ,halle method for potash1 #bgj1 #bga ,hen manure1 #cab ,hess1 method for estimating iron and alumina in phosphates1 #be1 #bf ,holleman1 silver method for phosphoric acid1 #aag ,horn1 hoof1 and hair1 #afe ,huston1 calcium chlorid method1 #bhb digestion apparatus1 #adb1 #adc mechanical stirrer1 #add1 #ade solubility of reverted phosphoric acid1 #acb1 #aci ,i ,immendorff1 method for estimating lime1 #bc ,indicator for nitrogen determination1 #bjd ,iodin1 determination in phosphates1 #abg ,iron1 acetate method1 #bd determination in ashes1 #cbj estimation in phosphates1 #bd-bf1 #bh-ca ,j ,jodlbaur method1 ,dutch variation1 #bac1 #bad for nitrogen1 #bab1 #bac ,halle modification1 #bad ,johnson and ,jenkins1 method for nitrogen1 #agg citrate method1 #ei comparison of citrate and molybdate methods1 #fi1 #gj ,jones modification of ,glaser method1 #bh reductor1 #aae ,jptner1 tartaric acid solution1 #ag ,k ,kainit1 #bei methods for analysis1 #bgd-bgg ,kieserit1 #bfc methods for analysis #bgd-bgg ,kjeldahl method1 #aib-baf ,dutch process1 #bjj ,halle process1 #bjj-bjd modifications1 #bji-baf official for nitric nitrogen1 #bae process1 #bjd-bjg original process1 #aic-aif preparation of reagents1 #afg-aii theory of reactions1 #aig ,knorr apparatus for carbon dioxid1 #ai ,kreider1 perchlorate process1 #bif ,krug and ,mc,elroy1 estimation of iron and alumina in phosphates1 #cb1 #cc ,krugit1 #bfb ,l ,land plaster1 #cag ,leather waste1 #cad ,lime1 action1 #cjc-cje analysis1 #cje application1 #cjc as a fungicide and insecticide1 #cje compounds used as fertilizer1 #cjb determination1 in ashes1 #cbj of state of combustion1 #cjf1 #cjg estimation in basic slags1 #hj1 #ha phosphates1 #ba-bc1 #ce of caustic1 #ha preparation of sample1 #cjf ,mc ,mc,elroy1 method of analysis for wood ashes1 #cai-cbb separation of iron and alumina from phosphoric acid1 #cc1 #cd ,m ,manganese1 determination in ashes1 #cbj ,magnesia1 determination in wood ashes1 #cbj error due to occluded1 #ed estimation in phosphates1 #ce mixture1 preparation1 #ag1 #de removal in perchlorate process1 #bih ,magnesium compounds1 action in manufacture of superphosphates1 #aed nitrate1 preparation1 #de pyrophosphate1 color1 #ee1 #ef ,manure1 definition1 #a sampling barnyard1 #i ,marioni and ,fasselli1 modification of ,glaser's method1 #ca1 #cb ,mercury pump1 #agc1 #agd ,mills for crushing fertilizing minerals1 #e ,minerals containing fertilizing materials1 #e ,moist combustion process1 historical1 #aib ,moisture1 determination in ashes1 #bai in monocalcium phosphates1 #ac1 #ad ,molybdate and citrate methods1 comparative accuracy1 #fi method1 adopted by ,brussels congress1 #fg sources of error1 #ec ,molybdedum precipitate1 direct weighing1 #aej ,molybdic solution1 preparation1 #ag1 #de ,morgen1 citrate method1 #fj-fe ,n ,neubauer1 investigation of error1 #ed1 #ee ,nitric nitrogen1 #afh estimation1 #bbg ,krger's method1 #bca ,schlesing-,wagner method1 #bbh1 #bbi ,schmitt's modification1 #bcj ,ulsch method1 #bbg separation1 #bbf ,nitrifiable solution1 #bdc ,nitrogen analysis1 calculation of results1 #agg table for calculating results1 #ahc as ammonia1 #bba1 #bbb determination by ,boussingault1 #bbb1 #bbc cost per pound1 #c1 #d forms of occurrence1 #afa1 #afb kinds in fertilizers1 #afa method of volumetric determination in laboratory1 #age1 #agf methods of analysis1 classification1 #afi official methods1 #agj volumetric method1 #aga1 #agb qualitative determination of form1 #afb1 #afc ,nitrogenous fertilizers1 source1 #afc1 #afi ,norwegian methods1 #de1 #dg ,noyes and ,royse1 determination of phosphoric acid in the presence of iron1 #aac1 #aad ,o ,official method for phosphoric acid1 #af volumetric method1 rarely used1 #agc ,ogilvie1 separation of alumina from phosphoric acid1 #ca1 #cb ,organic fertilizing materials1 sampling1 #h matters1 destruction1 #bee by moist combustion1 #bef sulfuric acid1 #ef1 #eg1 #adg1 #adh in phosphates1 #ci ignition with sulfuric acid1 #bee in phosphates1 #ah ,p ,patrick1 distilling flask1 #bji ,pemberton method1 comparison with official1 #aji of preparing reagents1 #ajg1 #ajh volumetric method for phosphoric acid1 #ajf ,perchlorate process1 accuracy1 #cjj applicability1 #bii comparison of results1 #bih method of ,kreider1 #bif1 #big ,perchloric acid1 composition1 #bie keeping properties1 #bie preparation1 method of ,caspari1 #bij1 #bia ,kreider1 #bib-bid reagent for potash1 #bhf ,phosphates1 constituents to be determined1 #ae insoluble matter1 #bj low cost1 #c moisture in monocalcium1 #ac1 #ad natural manurial value1 #d preparation of solution1 #bj soluble matter1 #ai ,phosphatic fertilizers1 availability1 #adh1 #adi slags1 adulteration1 #ha detection1 #hb-hf analysis1 #ge-ha manufacture1 #ga1 #gb solubility1 #gd ,phosphomolybdic acid1 reagent for potash1 #bhi ,phosphoric acid1 condition in superphosphates1 #aja cost per pound1 #c determination as stannic phosphate1 #dj by official method1 #af titration of yellow precipitate1 #ajf-aaj in ashes1 #cba basic slag1 #ea bone meal1 #ea fish-guano1 #ea mineral phosphates1 #ea1 #ec superphosphates1 #ej direct estimation1 #ae ,dutch method of determination1 #ea-ec error due to volatility1 #ed estimation as a lead compound1 #aaj in presence of iron1 #aab molybdenum technical method1 #abj1 #aba preparation of reagents for technical determination1 #aah1 #aai separation in wood ashes1 #cai silver method1 #aaf1 #aag sources1 #ci ,swedish methods of determining1 #di1 #ej technical determination1 #aah-abe volumetric uranium method1 #aba1 #abb time required for precipitation1 #abf typical solution1 #ie used for superphosphate manufacture1 #aef volumetric determination1 #hf-aah ,platinic chlorid1 method for potash1 #bfg official1 #bfg1 #bfh ,platinum method1 sources of error1 #bhd1 #bhe waste1 recovery1 #bhg-bhi weighing metallic precipitate1 #bhc1 #bhd ,polyhalit1 #bfa ,potash analysis1 classification of methods1 #bff consumption1 #bfe1 #bff cost per pound1 #d ,dutch method for analysis1 #bgb estimation as perchlorate1 #bhi-cjj table of factors1 #bhg forms found in fertilizers1 #bdi ,halle method for analysis1 #bgj1 #bga in molasses1 #bed winery residues1 #bee methods of analysis1 #bff-cjj occurrences in mineral deposits1 #bef1 #beg official alternate method1 #bfi recovered from factory residues1 #bfe salts1 changes in situ1 #beg control method for analysis1 #bhc effect of concentration on accuracy of analysis1 #bhe1 #bhf geological occurrence1 #beh methods for analyzing concentrated1 #bgh-bhj solution from organic compounds1 #bgj sources1 #bdh ,swedish method for analysis1 #bgc ,potassium hydroxid solution1 tension of vapor1 #ahb magnesium carbonate1 #bfe platinochlorid1 differences in crystalline form1 #bhf sulfate1 grades as fertilizers1 #bfd ,pyrophosphate1 examination1 for impurities1 #abf ,r ,reverted phosphates1 reversion by ammonium citrate1 #ajc1 #ajd phosphoric acid1 arbitrary determination1 #aci definition1 #aci1 #adj determination by uranium method1 #ajb ,robinson1 sources of error in platinum method1 #bhd1 #bhe ,roode1 de1 method for kainit1 #bha ,ross1 direct precipitation of citrate soluble phosphoric acid1 #adg ,ruffle method1 #ahh ,boyer's modification1 #aij1 #aia official1 #ahh-aij ,s ,salt1 #cji analysis1 #caj ,samples1 directions for taking bulk1 #bdc ,french method of preparation1 #aj ,german method of preparation1 #aj official method of preparation1 #aj special cases1 #ab taking1 #d ,sanborn1 method of filtering phosphoric acid1 #db ,sand in wood ashes1 #cae1 #caf1 #cai ,schnit1 #bfd ,schweitzer and ,lungwitz1 method for potash1 #bha ,scovell1 method for nitrogen1 #bae ,seeds and seed residues1 #afc ,shaking apparatus1 #gh1 #gi ,silica1 error due to occluded1 #ec estimation in phosphates1 #bj in wood ashes1 #cae1 #caf1 #cai ,slags1 basic phosphate1 #gj composition1 #gb1 #gc manufacture1 #ga1 #gb ,soda-lime process1 #ahc1 #ahd ,french method1 #ahf hydrogen method1 #ahg official method1 #ahd-ahf preparation of samples1 #ahg ,sodium nitrate1 functions1 #bca1 #bcb value1 #bdf ,soluble phosphoric acid1 determination by uranium method1 #ajb ,german method of estimating1 #dg1 #dh ,spencer1 silver method for phosphoric acid1 #aaf ,stall manures1 #caa ,stannic chlorid1 reagent for determining phosphoric acid1 #dj ,sterilized tubes1 for sampling1 #bda ,stone and ,scheuch1 estimation of caustic lime1 #ha ,sulfuric acid1 determination in ashes1 #cba estimation in phosphates1 #ce quantity used in the manufacture of superphosphates1 #aed1 #aee removal in perchlorate process1 #bih ,superphosphates1 action of iron and alumina compounds in manufacture1 #aec chemical reactions in manufacture1 #aea definition1 #aej1 #aea determination by uranium method1 #ajb manufacture1 #aej-aef with phosphoric acid1 #aef quantity of sulfuric acid used in manufacture1 #aed1 #aee technical analysis1 #abd1 #abe ,sylvin1 #bfb ,sylvinit1 #bfc methods for analysis1 #bgd-bgg ,t ,tankage1 #afe ,tartaric acid1 use1 in molybdenum solution1 #ag ,tetracalcium phosphate1 molecular structure1 #gc ,thiocyanates in fertilizers1 determination1 #bbd ,tobacco stems1 #bej and waste1 composition of ash1 #bej waste1 #bej ,total phosphoric acid1 treatment1 #db1 #dc ,u ,uranium method for phosphoric acid1 #hh-aja preparation of standard solution1 #id process1 causes of errors1 #ih1 #ii correction1 #ig titration of sample of phosphate1 #ajj solution1 titration1 #if ,v ,vanadium1 methods of estimation1 #abh1 #abi ,van ,slyke1 reactions of gunning method1 #bah ,voorhees1 method for nitrates1 #bbj ,w ,waste matters as fertilizers1 #b ,water1 determination in phosphates1 #ah soluble phosphoric acid1 #da volumetric estimation1 #aaa ,wells1 citrate method1 #ei ,wilfarth1 method for nitrogen1 #baa ,winton and ,voorhees1 gunning method for nitrates1 #bbj potash analysis1 #bhe1 #bhf ,wood ashes1 #bea1 #cae composition1 #beb ,wyatt1 method for determining iron and alumina in phosphates1 #cd estimating fluorin1 #cg1 #ch lime1 #bb