,,standard ,,methods ,,for ,,the ,,examination ,,of ,,water ,,and ,,sewage ,,fourth ,,edition ,revised by committees of the ,american ,public ,health ,association1 ,american ,chemical ,society1 and referees of the ,association of ,official ,agricultural ,chemists ,,american ,,public ,,health ,,association #afi ,,massachusetts ,,avenue ,,boston #aibj ,copyright1 #aiag and #aibj ,by the ,american ,public ,health ,association ---------------------------------------- -------------------------------- ,,contents4 ,,page ,,preface ,,to ,,the ,,fourth ,,edition vii ,,collection ,,of ,,samples #a ,,quantity ,,of ,,water ,,required ,,for ,,analysis #a ,,bottles #a ,,time ,,interval ,,between ,,collection ,,and ,,analysis #b ,,representative ,,samples #c ,,physical ,,examination #d ,,temperature #d ,,turbidity #d ,,turbidity ,,standard #d ,,platinum ,,wire ,,method #e ,,turbidimetric ,,method #g ,,coefficient ,,of ,,fineness #h ,,color #i ,,comparison ,,with ,,platinum-,,cobalt ,,standards #i ,,comparison ,,with ,,glass ,,disks #aj ,,comparison ,,with ,,nessler ,,standards #aj ,,lovibond ,,tintometer #aa ,,odor #ab ,,cold ,,odor #ab ,,hot ,,odor #ab ,,expression ,,of ,,results #ab ,,chemical ,,examination #ad ,,expression ,,of ,,results #ad ,,forms ,,of ,,nitrogen #ae ,,ammonia ,,nitrogen #ae ,,determination ,,by ,,distillation #ae ,,measurement ,,of ,,ammonia ,,nitrogen #af ,,comparison ,,with ,,ammonia ,,standards #af ,,comparison ,,with ,,permanent ,,standards #ag ,,modification ,,for ,,sewage #ah ,,determination ,,by ,,direct ,,nesslerization #ai ,,albuminoid ,,nitrogen #bj ,,organic ,,nitrogen #ba ,,nitrite ,,nitrogen #bb ,,nitrate ,,nitrogen #bc ,,phenoldisulfonic ,,acid ,,method #bc ,,reduction ,,method #bd ,,total ,,nitrogen #be ,,oxygen ,,consumed #be ,,recommended ,,method #bf ,,other ,,methods #bg ,,residue ,,on ,,evaporation #bi ,,total ,,residue #bi ,,fixed ,,residue ,,and ,,loss ,,on ,,ignition #bi ,,suspended ,,matter #cj ,,determination ,,with ,,gooch ,,crucible #cj ,,determination ,,by ,,filtration #cj ,,determination ,,of ,,volume #cj ,,fixed ,,residue ,,and ,,loss ,,on ,,ignition #cj ,,hardness #cj ,,total ,,hardness ,,by ,,calculation #ca ,,total ,,hardness ,,by ,,soap ,,method #ca ,,total ,,hardness ,,by ,,soda ,,reagent ,,method #cd ,,temporary ,,hardness ,,by ,,titration ,,with ,,acid #cd ,,non-,,carbonate ,,hardness ,,by ,,soda ,,reagent ,,method #cd ,,non-,,carbonate ,,hardness ,,by ,,soap ,,method #ce ,,alkalinity #ce ,,procedure ,,with ,,phenolphthalein #cf ,,procedure ,,with ,,methyl ,,orange #cg ,,procedure ,,with ,,lacmoid #cg ,,procedure ,,with ,,erythrosine #cg ,,bicarbonate #cg ,,normal ,,carbonate #ch ,,hydroxide #ch ,,alkali ,,carbonates #ci ,,acidity #ci ,,total ,,acidity #dj ,,free ,,carbon ,,dioxide #dj ,,free ,,mineral ,,acids #da ,,mineral ,,acids ,,and ,,sulfates ,,of ,,iron ,,and ,,aluminium #da ,,chloride #da ,,iron #dc ,,total ,,iron #dd ,,colorimetric ,,method #dd ,,comparison ,,with ,,iron ,,standards #de ,,comparison ,,with ,,permanent ,,standards #df ,,volumetric ,,method #df ,,dissolved ,,iron #dg ,,suspended ,,iron #dg ,,ferrous ,,iron #dg ,,ferric ,,iron #dh ,,manganese #dh ,,persulfate ,,method #dh ,,bismuthate ,,method #di ,,lead1 ,,zinc1 ,,copper1 ,,and ,,tin #ej ,,lead #ea ,,zinc #eb ,,copper #ec ,,tin #ed ,,mineral ,,analysis #ef ,,residue ,,on ,,evaporation #ef ,,alkalinity ,,and ,,acidity #ef ,,chloride #ef ,,nitrate ,,nitrogen #ef ,,separation ,,of ,,silica1 ,,iron1 ,,aluminium1 ,,calcium1 ,,and ,,magnesium #ef ,,silica #ef ,,iron ,,and ,,aluminium #eg ,,calcium #eg ,,magnesium #eg ,,separation ,,of ,,sulfate1 ,,sodium1 ,,and ,,potassium #eh ,,sulfate #eh ,,sodium1 ,,potassium ,,and ,,lithium #eh ,,potassium #ei ,,lithium #fj ,,bromine1 ,,iodine1 ,,arsenic1 ,,and ,,boric ,,acid #fa ,,bromine ,,and ,,iodine #fa ,,arsenic #fc ,,boric ,,acid #fc ,,hydrogen ,,sulfide #fc ,,chlorine #fd ,,dissolved ,,oxygen #fe ,,ether-,,soluble ,,matter #fi ,,relative ,,stability ,,of ,,effluents #fi ,,biochemical ,,oxygen ,,demand ,,of ,,sewages ,,and ,,effluents #ga ,,relative ,,stability ,,method #ga ,,sodium ,,nitrate ,,method #gb ,,analysis ,,of ,,sewage ,,sludge ,,and ,,mud ,,deposits #gc ,,collection ,,of ,,sample #gc ,,reaction #gc ,,specific ,,gravity #gd ,,moisture #gd ,,volatile ,,and ,,fixed ,,matter #gd ,,total ,,organic ,,nitrogen #gd ,,ether-,,soluble ,,matter #ge ,,ferrous ,,sulfide #gf ,,biochemical ,,oxygen ,,demand #gf ,,analysis ,,of ,,chemicals #gg ,,reagents #gg ,,sulfate ,,of ,,aluminium #gh ,,insoluble ,,matter #gh ,,oxides ,,of ,,aluminium ,,and ,,iron #gh ,,total ,,iron #gi ,,ferric ,,iron #gi ,,ferrous ,,iron #hj ,,basicity ,,ratio #hj ,,lime #hj ,,sulfate ,,of ,,iron #ha ,,insoluble ,,matter #ha ,,iron ,,as ,,ferrous ,,sulfate #ha ,,acidity #ha ,,soda ,,ash #hb ,,insoluble ,,matter #hb ,,available ,,alkali #hb ,,chemical ,,bibliography #hb ,,microscopical ,,examination #hi ,,microscopical ,,bibliography #ia ,,bacteriological ,,examination #ib ,,apparatus #ib ,,sample ,,bottles #ib ,,pipettes #ib ,,dilution ,,bottles #ib ,,petri ,,dishes #ib ,,fermentation ,,tubes #ib ,,materials #ic ,,water #ic ,,meat ,,extract #ic ,,peptone #ic ,,sugars #ic ,,agar #ic ,,gelatin #ic ,,litmus #ic ,,general ,,chemicals #ic ,,methods #ic ,,preparation ,,of ,,culture ,,media #ic ,,titration #ic ,,sterilization #id ,,nutrient ,,broth #ie ,,sugar ,,broths #ie ,,nutrient ,,gelatin #ie ,,nutrient ,,agar #if ,,litmus ,,or ,,azolitmin ,,solution #if ,,litmus-,,lactose-,,agar #ig ,,endo',s ,,medium #ig ,,collection ,,of ,,sample #ih ,,storage ,,and ,,transportation ,,of ,,sample #ih ,,dilutions #ih ,,plating #ii ,,incubation #ii ,,counting #ii ,,the ,,test ,,for ,,the ,,presence ,,of ,,members ,,of ,,the ,b4 ,,coli ,,group #ajj ,,presumptive ,,test #ajj ,,partially ,,confirmed ,,test #aja ,,completed ,,test #ajb ,,application ,,of ,,these ,,tests #ajb ,,expression ,,of ,,results #ajc ,,summary ,,of ,,these ,,tests #ajd ,,interpretation ,,of ,,results #ajf ,,differentiation ,,of ,,fecal ,,from ,,non-,,fecal ,,members ,,of ,,the ,b4 ,,coli ,,group #ajf ,,methyl ,,red ,,test #ajg ,,voges-,,proskauer ,,test #ajh ,,routine ,,procedure ,,for ,,bacteriological ,,examination #ajh ,,bacteriological ,,bibliography #aaj ,,index #aac ,,preface ,,to ,,fourth ,,edition4 ,the ,committee on ,standard ,methods of ,bacteriological ,water ,analysis was reorganized in #aiah with the following membership3 ,f4 ,p4 ,gorham1 chairman1 ,l4 ,a4 ,rogers1 ,w4 ,g4 ,bissell1 ,h4 ,e4 ,hasseltine1 ,h4 ,w4 ,redfield1 with ,m4 ,levine as adjunct member4 ,this committee made a report in #aiah which was not acted on by the ,laboratory ,section1 and in #aiai made a revised report1 recommending certain changes in ,standard ,methods1 which were adopted by the section and which are now incorporated in this present fourth edition4 ,following are the more important changes3 ,new brands of peptone authorized4 ,phenol ,red ,method of ,hydrogen-ion ,concentration4 ,five-tenths per cent of sugar specified for broths instead of #a per cent4 ,sterilization of sugar is media specified in greater detail4 ,preparation of ,endo ,medium4 ,synthetic ,medium for the ,methyl ,red ,test4 ,there are no changes in the chemical methods in this edition4 ,,american ,,public ,,health ,,association4 ,,laboratory ,,section4 ,,standard ,,methods ,,for ,,the ,,examination ,,of ,,water ,,and ,,sewage4 ,compiled and revised by committees of the ,american ,public ,health ,association and the ,american ,chemical ,society and referees of the ,association of ,official ,agricultural ,chemists4 ,,collection ,,of ,,samples4 ,,quantity ,,required ,,for ,,analysis4 ,the minimum quantity necessary for making the ordinary physical1 chemical1 and microscopical analyses of water or sewage is #b liters2 for the bacteriological examination1 #ajj cc4 ,in special analyses larger quantities may be required4 ,,bottles4 ,the bottles for the collection of samples shall have glass stoppers1 except when physical1 mineral1 or microscopical examinations only are to be made4 ,jugs or metal containers shall not be used4 ,sample bottles shall be carefully cleansed each time before using4 ,this may be done by treating with sulfuric acid and potassium bichromate1 or with alkaline permanganate1 followed by a mixture of oxalic and sulfuric acids1 and by thoroughly rinsing with water and draining4 ,the stoppers and necks of the bottles shall be protected from dirt by tying cloth1 thick paper or tin foil over them4 ,for shipment bottles shall be packed in cases with a separate compartment for each bottle4 ,wooden boxes may be lined with corrugated fibre paper1 felt1 or similar substance1 or provided with spring corner strips1 to prevent breakage4 ,lined wicker baskets also may be used4 ,bottles for bacteriological samples shall be sterilized as directed on page #ih4 ,,interval ,,before ,,analysis4 ,in general1 the shorter the time elapsing between the collection and the analysis of a sample the more reliable will be the analytical results4 ,under many conditions analyses made in the field are to be commended1 as data so obtained are frequently preferable to data obtained in a distant laboratory after the composition of the water has changed4 ,the time that may be allowed to elapse between the collection of a sample and the beginning of its analysis cannot be stated definitely4 ,it depends on the character of the sample1 the examinations to be made1 and other conditions4 ,the following are suggested as fairly reasonable maximum limits4 ,physical and chemical analysis4 ,ground waters #gb hours ,fairly pure surface waters #dh ,polluted surface waters #ab ,sewage effluents #f ,raw sewages #f ,microscopical examination4 ,ground waters #gb hours ,fairly pure surface waters #bd ,waters containing fragile organisms ,immediate examination ,bacteriological examination4 ,samples kept at less than #aj;,c #bd hours ,if a longer period elapses between collection and examination the time should be noted4 ,if sterilized by the addition of chloroform1 formaldehyde1 mercuric chloride1 or some other germicide samples for sanitary chemical examination may be allowed to stand for longer periods than those indicated1 but as this is a matter which will vary according to circumstances1 no definite procedure is recommended4 ,if unsterilized samples of sewage1 sewage effluents1 and highly polluted surface waters are analyzed after greater intervals than those suggested caution must be used in interpreting analyses of the organic content1 which frequently changes materially upon standing4 ,determinations of dissolved gases1 especially oxygen1 hydrogen sulfide1 and carbon dioxide1 should be made at the time of collection in order to be reasonably accurate1 in accordance with the directions given hereafter in connection with each determination4 ,,representative ,,samples4 ,care should be taken to obtain a sample that is truly representative of the liquid to be analyzed4 ,with sewages this is especially important because marked variations in composition occur from hour to hour4 ,satisfactory samples of some liquids can be obtained only by mixing together several portions collected at different times or at different places--the details as to collection and mixing depending upon local conditions4 ,,physical ,,examination4 ,,temperature4 ,the temperature of the sample1 if taken1 shall be taken at the time of collection1 and shall be expressed preferably in degrees ,centigrade1 to the nearest degree1 or closer if more precise data are required4 ,the thermophone#aji is recommended for obtaining the temperature of water at various depths below the surface4 ,,turbidity4 ,the turbidity of water is due to suspended matter1 such as clay1 silt1 finely divided organic matter1 microscopic organisms1 and similar material4 ,,turbidity ,,standard4#aaj ,the standard of turbidity shall be that adopted by the ,united ,states ,geological ,survey1 namely1 a water which contains #ajj parts per million of silica in such a state of fineness that a bright platinum wire #a millimeter in diameter can just be seen when the center of the wire is #ajj millimeters below the surface of the water and the eye of the observer is #a4b meters above the wire1 the observation being made in the middle of the day1 in the open air1 but not in sunlight1 and in a vessel so large that the sides do not shut out the light so as to influence the results4 ,the turbidity of such water is arbitrarily fixed at #ajj parts per million4 ,for preparation of the silica standard dry ,pear's 8precipitated fuller's earth0 and sift it through a #bjj-mesh sieve4 ,one gram of this preparation in #a liter of distilled water makes a stock suspension which contains #a1jjj parts per million of silica and which should have a turbidity of #a1jjj4 ,test this suspension1 after diluting a portion of it with nine times its volume of distilled water1 by the platinum wire method to ascertain if the silica has the necessary degree of fineness and if the suspension has the necessary degree of turbidity4 ,if not1 correct by adding more silica or more water as the case demands4,a ,footnote ,a3 ,this method of correction very slightly alters the coefficient of fineness of the standard1 but does not noticeably affect its use4 ,standards for comparison shall be prepared from this stock suspension by dilution with distilled water4 ,for turbidity readings below #bj1 standards of #j1 #e1 #aj1 #ae1 and #bj shall be kept in clear glass bottles of the same size as that containing the sample2 for readings above #bj1 standards of #bj1 #cj1 #dj1 #ej1 #fj1 #gj1 #hj1 #ij1 and #ajj shall be kept in #ajj cc4 ,nessler tubes approximately #bj millimeters in diameter4 ,comparison with the standards shall be made by viewing both standard and sample sidewise toward the light by looking at some object and noting the distinctness with which the margins of the object can be seen4 ,the standards shall be kept stoppered1 and both sample and standards shall be thoroughly shaken before making the comparison4 ,in order to prevent any bacterial or algal growths from developing in the standards a small amount of mercury bichloride may be added to them4 ,,platinum ,,wire ,,method4#db ,this method requires a rod with a platinum wire #a mm4 in diameter inserted in it about #a inch from one end of the rod and projecting from it at a right angle at least #be mm4 ,near the other end of the rod1 at a distance of #a4b meters from the platinum wire1 a small ring shall be placed directly above the wire through which1 with his eye directly above the ring1 the observer shall look when making the examination4 ,the rod shall be graduated as follows3 ,the graduation mark of #ajj shall be placed on the rod at a distance of #ajj mm4 from the center of the wire4 ,other graduations shall be made according to ,table #a1 which is based on the best obtainable data4 ,the distances recorded in ,table #a are intended to be such that when the water is diluted the turbidity readings will decrease in the same proportion as the percentage of the original water in the mixture4 ,these graduations are those on what is known as the ,u4 ,s4 ,geological ,survey ,turbidity ,rod of #aijb4aje ,table #a4--;,,graduation ,,of ,,turbidity ,,rod4 ,turbidity ,vanishing depth of wire 7mm474 7parts per million74 #g #ajie #h #iga #i #hgc #aj #gid #aa #gbi #ab #fgd #ac #fbg #ad #ehg #ae #eea #af #ebj #ag #dic #ah #dfh #ai #ddf #bj #dbf #bb #cia #bd #cfa #bf #ccf #bh #cad #cj #bif #ce #beg #dj #bbh #de #bje #ej #ahg #ee #aga #fj #aeh #fe #adg #gj #ach #ge #acj #hj #abb #he #aaf #ij #aaj #ie #aje #ajj #ajj #aaj #ic #abj #hf #acj #ha #adj #gf #aej #gb #afj #fh4g #ahj #fb4d #bjj #eg4d #bej #di4a #cjj #dc4b #cej #ch4h #djj #ce4d #ejj #cj4i #fjj #bg4g #hjj #bc4d #ajjj #bj4i #aejj #ag4a #bjjj #ad4h #cjjj #ab4a ,procedure4--,lower the rod vertically into the water as far as the wire can be seen and read the level of the surface of the water on the graduated scale4 ,this will indicate the turbidity4 ,the following precautions shall be taken to insure correct results3 ,observations shall be made in the open air1 preferably in the middle of the day and not in direct sunlight4 ,the wire shall be kept bright and clean4 ,if for any reason observations cannot be made directly under natural conditions a pail or tank may be filled with water and the observation taken in that1 but if this is done care shall be taken that the water is thoroughly stirred before the observation is made1 and no vessel shall be used for this purpose unless its diameter is at least twice as great as the depth to which the wire is immersed4 ,waters which have a turbidity greater than #ejj shall be diluted with clear water before the observations are made1 but if this is done the degree of dilution shall be reported4 ,,turbidimetric ,,method4 ,several forms of turbidimeter or diaphanometer#gc have been suggested for use4 ,the simplest and most satisfactory form is the candle turbidimeter4#aaf ,this consists of a graduated glass tube with a flat polished bottom1 enclosed in a metal case4 ,this is supported over an ,english standard candle and so arranged that one may look vertically down through the tube at the flame of the candle4 ,the observation is made by pouring the sample of water into the tube until the image of the flame of the candle just disappears from view4 ,care shall be taken not to allow soot or moisture to accumulate on the lower side of the glass bottom of the tube so as to interfere with the accuracy of the observations4 ,the graduations on the tube correspond to turbidities produced in distilled water by certain numbers of parts per million of silica standard4 ,in order to insure uniform results it is necessary to have the distance between the top rim of the candle and the bottom of the tube constant1 and this distance shall be #g4f cm4 or #c inches4 ,the observations shall be made in a darkened room or with a black cloth over the head4 ,it is allowable to substitute for the candle an electric light4 ,calibrate the apparatus to correspond with the ,united ,states ,geological ,survey scale4 ,the figures in ,table #b on page #h are believed to be approximately correct for the candle turbidimeter but should be checked by the experimenter4 ,it is allowable to calibrate the tube of the instrument with waters of known turbidity prepared by making a series of dilutions of the silica standard with distilled water4 ,from the figures obtained in calibrating plot a curve from which the turbidity of a sample may be read when the depth of water in the tube has been obtained4 ,table #b4--;,,graduation ,,of ,,candle ,,turbidimeter4 ,depth of liquid ,turbidity 7cm474 7parts per million of silica74 #b4c #ajjj #b4f #ijj #b4i #hjj #c4b #gjj #c4e #fej #c4h #fjj #d4a #eej #d4e #ejj #d4i #dej #e4e #djj #e4f #cij #e4h #chj #e4i #cgj #f4a #cfj #f4c #cej #f4d #cdj #f4f #ccj #f4h #cbj #g4j #caj #g4c #cjj #g4e #bij #g4h #bhj #h4a #bgj #h4d #bfj #h4g #bej #i4a #bdj #i4e #bcj #i4i #bbj #aj4c #baj #aj4i #bjj #aa4d #aij #ab4j #ahj #ab4g #agj #ac4e #afj #ad4d #aej #ae4d #adj #af4f #acj #ah4j #abj #ai4f #aaj #ba4e #ajj ,the results of turbidity observations shall be expressed in whole numbers which correspond to parts per million of silica and recorded as follows3 ,turbidity between #a;and #ejrecorded to nearestunit #ea #ajj #e #aja #ejj #aj #eja #ajjj #ej #ajja greater #ajj ,,coefficient ,,of ,,fineness#hj ,the quotient obtained by dividing the weight of suspended matter in the sample by the turbidity1 both expressed in the same unit1 shall be called the coefficient of fineness4 ,if the quotient is greater than unity the matter in suspension is coarser and if it is less than unity it is finer than the standard4 ,,color4 ,the 8color10 or the 8true color10 of water shall be considered the color that is due only to substances in solution2 that is1 it is the color of the water after the suspended matter has been removed4 ,in stating results the word 8color0 shall mean the 8true color0 unless otherwise designated4 ,the 8apparent color0 shall be considered as including not only the true color but also any color produced by substances in suspension4 ,it is the color of the original unfiltered sample4 ,the platinum-cobalt method of measuring color shall be considered as the standard1 and the unit of color shall be that produced by #a part per million of platinum4 ,,comparison ,,with ,,platinum-,,cobalt ,,standards4#dc ,reagents4--,dissolve #a4bdf grams of potassium platinic chloride 7,pt,cl#db,k,cl71 containing #j4e gram platinum1 and #a4jj gram crystallized cobalt chloride 7,co,cl#b4f;,h#b,o71 containing #j4be gram of cobalt1 in water with #ajj cc4 concentrated hydrochloric acid1 and dilute to #a liter with distilled water4 ,this solution has a color of #ejj4 ,dilute this solution with distilled water in #ej cc4 ,nessler tubes to prepare standards having colors of #j1 #e1 #aj1 #ae1 #bj1 #be1 #cj1 #ce1 #dj1 #ej1 #fj1 and #gj4 ,keep these standards in ,nessler tubes of such diameter that the graduation mark is between #bj and #be cm4 above the bottom and of such uniformity that they match within such limit that the distance from the bottom to the graduation mark of the longest tube shall not exceed that of the shortest tube by more than #f mm4 ,protect the tubes from dust and light when not in use4 ,procedure4--,the color of a sample shall be observed by filling a standard ,nessler tube to the height equal to that in the standard tubes with the sample and by comparing it with the standards4 ,the observation shall be made by looking vertically downward through the tubes upon a white or mirrored surface placed at such angle that light is reflected upward through the column of liquid4 ,water that has a color greater than #gj shall be diluted before making the comparison1 in order that no difficulties may be encountered in matching the hues4 ,water containing matter in suspension shall be filtered1 before the color observation is made1 until no visible turbidity remains4 ,if the suspended matter is coarse1 filter paper may be used for this purpose2 if the suspended matter is fine1 the use of a ,berkefeld filter is recommended4 ,the ,pasteur filter shall not be used as it exerts a marked decolorizing action4 ,the apparent color1 if determined1 shall be determined on the original sample without filtration4 ,the true and the apparent color of clear waters or waters with low turbidities are substantially the same4 ,the results of color determinations shall be expressed in whole numbers and recorded as follows3 ,color between #a and #ej recorded to nearest unit #ea #ajj #e #aja #bej #aj #bea #ejj #bj4 ,,comparison ,,with ,,glass ,,disks4#aje ,as the platinum-cobalt standard method is not well adapted for field work1 the color of the water to be tested may be compared with that of glass disks held at the end of metallic tubes through which they are viewed by looking toward a white surface4 ,the glass disks are individually calibrated to correspond with colors on the platinum scale4 ,experience has shown that the glass disks used by the ,u4 ,s4 ,geological ,survey give results in substantial agreement with those obtained by the platinum determinations1 and their use is recognized as a standard procedure4 ,,comparison ,,with ,,nessler ,,standards4 ,inasmuch as the ,nessler scale#fb and the natural water scale#bbdi which agrees with it except for colors less than #bj1 have been largely used in the past1 the old results may be converted#aag into terms of the platinum standard by means of the ratios in ,table #c1 but they must not be considered as universally applicable as the variable sensitiveness of the ,nessler solution introduces an uncertain factor4 ,table #c4--,,values ,,for ,,converting ,,colors ,,by ,,the ,,natural ,,water ,,scale ,,into ,,colors ,,by ,,the ,,platinum ,,standard ,,in ,,parts ,,per ,,million4,b ,modified ,nessler or natural #j4jj4j4ja4j4jb4j4jc4j4jd4j4je4j4jf4j4jg 4j4jh4j4ji4 water standard4 ,platinum-cobalt standard color4 #j4jj #j #b #d #f #h #i #aa #ac #ae #ag 4#aj #ah #ai #bj #bj #ba #bb #bc #bd #bd #bf 4#bj #bf #bg #bg #bh #bi #bi #cj #ca #cb #cb 4#cj #cc #cd #cd #ce #ce #cf #cg #cg #ch #ch 4#dj #ci #dj #dj #da #db #db #dc #dd #de #de 4#ej #df #dg #dg #dh #dh #di #ej #ej #ea #ea 4#fj #eb #ec #ec #ed #ed #ee #ef #ef #eg #eg 4#gj #eh #eh #ei #ei #fj #fj #fa #fa #fb #fb 4#hj #fc #fd #fd #fe #ff #ff #fg #fh #fi #fi 4#ij #gj #ga #gb #gc #gd #ge #gg #gh #gi #hj #a4jj #ha #hb #hb #hc #hd #hd #he #hf #hg #hg #a4aj #hh #hi #hi #ij #ia #ia #ib #ic #id #id #a4bj #ie #if #if #ig #ih #ih #ii #ajj #aja #aja #a4cj #ajb #ajc #ajc #ajd #aje #aje #ajf #ajg #ajh #ajh #a4dj #aji #aaj #aaj #aaa #aab #aab #aac #aad #aae #aae #a4ej #aaf #aag #aag #aah #aah #aai #abj #abj #aba #aba #a4fj #abb #abc #abc #abd #abe #abe #abf #abg #abh #abh #a4gj #abi #acj #acj #aca #acb #acb #acc #acd #ace #acf #a4hj #acf #acg #acg #ach #aci #aci #adj #ada #adb #adb #a4ij #adc #add #add #ade #adf #adf #adg #adh #adi #adi #b4jj #aej ,footnote ,b3 ,zero on the true ,nessler scale is about #ae on the platinum scale4 ,,lovibond ,,tintometer4 ,the value of the readings of tint and shade by the ,lovibond tintometer#ffhbhc has not been commensurate with the labor involved1 but it is necessary to make a record of the reflected tint and shade#ej of some waters4 ,the standard color disks used in teaching optics may be used for the purpose4 ,procedure4--,the white disk supports three movable standard color sectors1 red1 yellow1 and blue1 and one movable black sector4 ,all are mounted on a device which can be revolved rapidly1 blending the colors into a uniform tint or shade4 ,a scale around the circumference of the disk is used to indicate the percentage of each color or white or black in the blend4 ,place the sample in a battery jar on a white ground2 adjust the sectors so that when blended the tint or shade will match the reflected tint or shade of the sample4 ,report the percentages of red1 yellow blue1 white1 and black in the blended tint or shade4 ,,odor4#dadecgbibaadaaeaba;c ,the observation of the odor1 cold and hot1 of samples of surface water is important as the odors are usually indicative of organic growths or sewage contamination or both4 ,the odor of some ground waters is caused by the earthy constituents of the water-bearing strata4 ,the odor of a contaminated well water is often contributory evidence of its pollution4 ,a study of the organisms as directed under ,microscopical ,examination 7p4 #ij7 is a valuable adjunct to physical and chemical examination of water4 ,certain odors distinguish or identify certain organisms1 as1 for example1 the 8fishy0 odor of ,uroglena1 the 8aromatic0 or 8rose geranium0 odor of ,asterionella and the 8pig pen0 odor of ,anabaena4 ,observe and record the odor1 both at room temperature and at just below the boiling point1 as follows3 ,,cold ,,odor4 ,shake the sample violently in one of the collecting bottles1 when it is half to two-thirds full and when the sample is at room temperature 7about #bj ,c474 ,remove the stopper and smell the odor at the mouth of the bottle4 ,,hot ,,odor4 ,pour about #aej cc4 of the sample into a #ejj cc4 ,erlenmeyer flask4 ,cover the flask with a well-fitting watch glass4 ,heat the water almost to boiling on a hot plate4 ,remove the flask from the plate and allow it to cool not more than five minutes4 ,then agitate it with a rotary movement1 slip the watch glass to one side1 and smell the odor4 ,,expression ,,of ,,results4 ,express the quality of the odor by a descriptive epithet like the following1 which may be abbreviated in the record3 a--aromatic ,c--free chlorine d--disagreeable e--earthy f--fishy g--grassy m--moldy ,m--musty ,p--peaty s--sweetish ,s--hydrogen sulfide v--vegetable4 ,express the intensity of the odor by a numeral prefixed to the term expressing quality1 which may be defined as follows3 ,numerical ,term4 ,definition4 value4 #j ,none4 ,no odor perceptible4 #a ,very ,an odor that would not be detected ordinarily by faint4 the average consumer1 but that could be detected in the laboratory by an experienced observer4 #b ,faint4 ,an odor that the consumer might detect if his attention were called to it1 but that would not attract attention otherwise4 #c ,distinct4 ,an odor that would be detected readily and that might cause the water to be regarded with disfavor4 #d ,decided4 ,an odor that would force itself upon the attention and that might make the water unpalatable4 #e ,very ,an odor of such intensity that the water would be strong4 absolutely unfit to drink4 7,a term to be used only in extreme cases47 ,,chemical ,,examination4 ,,expression ,,of ,,results4 ,the results of chemical analyses shall be expressed in parts per million1 which in most analyses is practically equivalent to milligrams per liter4 ,in some laboratories other forms of expression have been used4 ,results expressed in parts per #ajj1jjj or in grains per gallon may be transformed to parts per million1 or conversely1 by the use of the following table3 ,table #d4--;,,factors ,,for ,,transforming ,,results ,,of ,,analyses4 ,unit4 ,equivalent4 ,grains ,grains per ,u4,s4 per ,parts per,parts per gallon4 ,imperial #ajj1jjj4 million4 gallon4 #a grain per ,u4 ,s4 gallon #a4jjj #a4bj #a4ga #ag4a #a grain per ,imperial gallon 4#hce #a4jj #a4dc #ad4c #a part per #ajj1jjj 4#ehe 4#gj #a4jj #aj4j #a part per million 4#jeh 4#jg 4#aj #a4j ,the following general rules shall govern the use of significant figures in the expression of results3 #a4 ,if the results show quantities greater than #aj parts per million use no decimals2 record only whole numbers4 ,if the quantities reach hundreds and thousands of parts record only two significant figures4 #b4 ,if the results are between #a and #aj parts do not retain more than one decimal place4 #c4 ,if the results are between #j4a and #a part do not retain more than two decimal places4 #d4 ,estimates of ammonia1 albuminoid1 and nitrite nitrogen alone justify the use of three decimals4 #e4 ,if the results of analyses are tabulated ciphers should not be added at the right of the decimal point to make the column uniform4 ,,forms ,,of ,,nitrogen4 ,nitrogenous organic matter passes through several intermediate compounds during its natural decomposition1 and that which does not gasify ultimately forms nitrate4 ,nitrogen in organic matter is determined by the ,kjeldahl process4#acadeh ,an indication of the amount present is obtained by the albuminoid nitrogen determination4#adaefgajfajg ,it has not been found possible to differentiate the nitrogen in the organic matter that readily decomposes from that in stable or non-putrescible compounds4 ,decomposition of organic matter produces nitrogen combined in ammonia1 which is the first step between nitrogenous organic matter and the completely mineralized nitrate4 ,ammonia nitrogen may be determined by distillation and ,nesslerization or by direct ,nesslerization of the clarified sample4 ,the next step is oxidation to nitrite1 and the final step1 oxidation to nitrate4 ,it is recommended that all forms of nitrogen be reported as the element nitrogen 7,n74 ,,ammonia ,,nitrogen4 ,there are two methods for estimating ammonia nitrogen--distillation and direct ,nesslerization4 ,distillation is recommended for most waters and direct ,nesslerization is recommended for sewages1 sewage effluents1 and highly polluted surface waters4 ,,determination ,,by ,,distillation4#chfh;b#aaaaba ,procedure4--,use a metal or a glass flask connected with a condenser so that the distillate may drop from the condenser tube directly into a ,nessler tube or a flask4 ,free the apparatus from ammonia by boiling distilled water in it until the distillate shows no trace of ammonia4 ,after this has been done empty the distilling flask and measure into it #ejj cc4 of the sample1 or a smaller portion diluted to #ejj cc4 with ammonia-free water4 ,if the sample is acid or if the presence of urea is suspected add about #j4e gram of sodium carbonate before distillation4 ,omit this if possible as it tends to increase 8bumping40 ,apply heat so that the distillation may proceed at the rate of not more than #aj cc4 nor less than #f cc4 per minute4 ,collect the distillate in four ,nessler tubes1 #ej cc4 to each tube1 or if the nitrogen is high in a #bjj cc4 graduated flask4 ,these receptacles contain the ammonia nitrogen to be measured as hereafter described4 ,use ,nessler tubes of such diameter that the graduation mark is between #bj and #be cm4 above the bottom and of such uniformity of diameter that the distance from the bottom to the graduation mark of the longest tube shall not exceed that of the shortest tube by more than #f mm4 ,the tubes must be of clear white glass with polished bottoms4 ,,measurement ,,of ,,ammonia ,,nitrogen4 ,the amount of ammonia in the distillates may be measured either by 7#a7 comparison of the ,nesslerized distillates with ,nesslerized solutions containing known quantities of nitrogen as ammonium chloride1 or by 7#b7 comparison of the ,nesslerized distillates with permanent standard solutions in which the colors of ,nesslerized standard ammonia solutions are duplicated by solutions of platinum and cobalt chlorides4 ,,comparison ,,with ,,ammonia ,,standards4 ,reagents4--#a4 ,ammonia-free water4 #b4 ,standard ammonium chloride solution4 ,dissolve #c4hb grams of ammonium chloride in ammonia-free water and dilute to #a liter2 dilute #aj cc4 of this to #a liter with ammonia-free water4 ,one cc4 equals #j4jjjja gram of nitrogen4 #c4 ,nessler reagent4#h ,dissolve #ej grams of potassium iodide in a minimum quantity of cold water4 ,add a saturated solution of mercuric chloride until a slight precipitate persists permanently4 ,add #djj cc4 of #ej per cent solution of potassium hydroxide1 made by dissolving the potassium hydroxide and allowing it to clarify by sedimentation before using4 ,dilute to #a liter1 allow to settle1 and decant4 ,this solution should give the required color with ammonia within five minutes after addition and should not produce a precipitate with small amounts of ammonia within two hours4 ,procedure4--,prepare a series of #af ,nessler tubes containing the following amounts of the standard ammonium chloride solution1 diluted to #ej cc4 with ammonia-free water1 namely3 #j4j1 #j4a1 #j4c1 #j4e1 #j4g1 #a4j1 #a4d1 #a4g1 #b4j1 #b4e1 #c4j1 #c4e1 #d4j1 #d4e1 #e4j1 and #f4j cc4 ,these solutions will contain #j4jjjja gram of nitrogen for each cubic centimeter of the standard solution4 ,nesslerize the standards and the distillates by adding approximately #a cc4 of ,nessler reagent to each tube4 ,do not stir the contents of the tubes4 ,the temperature of the tubes should be practically the same as that of the standards2 otherwise the colors will not be directly comparable4#de ,allow the tubes to stand at least #aj minutes after ,nesslerizing4 ,compare the color produced in the tubes with that in the standards by looking vertically downward through them at a white or mirrored surface placed at an angle in front of a window so as to reflect the light upward4 ,if the color obtained by ,nesslerizing the distillates is greater than that of the darkest tube of the standards1 mix the contents of the tube thoroughly1 pour out half of the liquid1 and dilute the remainder to the original volume with ammonia-free water2 then make the color comparison and multiply the result by two4 ,if the color is still too dark after pouring out half the liquid1 repeat this process of division until a reading can be made4 ,the process of dilution may be shortened by mixing together the distillates from one sample before making the comparison and comparing an aliquot portion with the standards4 ,after the readings have been recorded add the results obtained by ,nesslerizing each portion of the entire distillate4 ,if #ejj cc4 of the sample is distilled this sum1 expressed in cubic centimeters and multiplied by #j4jb1 will give the number of parts per million of ammonia nitrogen in the sample4 ,if x cc4 of sample is used multiply the sum of the readings by #aj_/x4 ,if the ammonia is known to be high the distillate may be collected in #bjj cc4 flasks and an aliquot part ,nesslerized4 ,,comparison ,,with ,,permanent ,,standards4#fbfe ,reagents4--,platinum solution4 ,dissolve #b4jj grams of potassium platinic chloride 7,pt,cl#d4b,k,cl7 in a small amount of distilled water1 add #ajj cc4 of strong hydrochloric acid1 and dilute to #a liter4 ,cobalt solution4 ,dissolve #ab grams of cobaltous chloride 7,co,cl#b4f;,h#b,o7 in distilled water1 add #ajj cc4 of strong hydrochloric acid1 and dilute to #a liter4 ,prepare standards by putting various amounts of these two solutions into ,nessler tubes and diluting to the #ej cc4 mark with distilled water as indicated in ,table #e4 ,these standards may be kept for several months if protected from dust4 ,table #e4--,,preparation ,,of ,,permanent ,,standards ,,for ,,the ,,determination ,,of ,,ammonia4 ,value in standard ,solution of platinum4 ,solution of cobalt4 ammonium chloride4 cc4 cc4 cc4 #j4j #a4b #j4j 4#a #a4h 4#j 4#b #b4h 4#j 4#d #d4g 4#a 4#g #e4i 4#b #a4j #g4g 4#e #a4d #i4i #a4a #a4g #aa4d #a4g #b4j #ab4g #b4b #b4e #ae4j #c4c #c4j #ag4c #d4e #c4e #ai4j #e4g #d4j #ai4g #g4a #d4e #ai4i #h4g #e4j #bj4j #aj4d #f4j #bj4j #ae4j #g4j #bj4j #bb4j ,the amounts in ,table #e are approximate1 and the actual amount necessary will differ with the character of the ,nessler solution1 the color sensitiveness of the analyst's eye1 and other conditions4 ,the final test of the standard is best obtained by comparing it with ,nesslerized standards and modifying the tint accordingly4 ,such comparison should be made for each new batch of ,nessler solution and should be checked by each analyst4 ,procedure4--,in comparison with permanent standards1 ,nesslerize the distillates in the manner above described and compare the resulting colors at the end of about #aj minutes with the permanent standards4 ,the method of calculating results is precisely the same as with the ammonia standards4 ,,modification ,,for ,,sewage4 ,ammonia nitrogen and albuminoid nitrogen in sewages1 soils1 and other materials of high nitrogen content may be satisfactorily determined by diluting the sample with ammonia-free distilled water and proceeding as described in the preceding sections1 but it is permissible to distill with steam4#dj ,procedure4--,use a #bjj cc4 long-necked ,kjeldahl flask connected with a condenser so that the distillate may drop from the condenser tube directly into a ,nessler tube or a flask4 ,connect the ,kjeldahl flask with a steam generator by a tube reaching almost to the bottom of the flask4 ,after the apparatus is freed from ammonia put the sample to be tested into the flask4 ,use #aj to #ajj cc4 of the sample according to its ammonia content4 ,pass ammonia-free steam through the liquid in the ,kjeldahl flask and collect the distillate in the usual way4 ,it is usually convenient to collect the distillate in a #bjj cc4 flask and to take an aliquot part of it for ,nesslerization4 ,compare with standards and calculate the nitrogen content in the usual manner4 ,this method has the advantage1 when the sample is treated with an alkaline solution of potassium permanganate1 of avoiding bumping1 permitting the assay of solid matter1 and yielding the ammonia more rapidly than by the ordinary process of distillation4 ,,determination ,,by ,,direct ,,nesslerization4#bage ,reagents4-- #a4 ,ten per cent solution of copper sulfate 7,cu,s,o#d4e;,h#b,o74 #b4 ,ten per cent solution of lead acetate 7,pb7,c#b;,h#c,o#b7b4c;,h#b,o74 #c4 ,fifty per cent solution of sodium hydroxide 7,na,o,h7 or potassium hydroxide 7,,koh74 ,procedure4--,to #ej cc4 of the sample to be tested1 diluted if necessary with an equal volume of ammonia-free water1 in a short tube1 add a few drops of the copper sulfate solution4 ,after thoroughly mixing1 add #a cc4 of the alkali hydroxide solution and again thoroughly mix4 ,allow the tube to stand for a few minutes1 when a heavy precipitate should fall to the bottom1 leaving a colorless supernatant liquid4 ,nesslerize an aliquot part4 ,compare with standards and compute the ammonia nitrogen in the same manner as in the distillation procedure4 ,samples containing hydrogen sulfide may require the use of lead acetate in addition to the copper sulfate4 ,some samples may require a few trials before the right combination of the three solutions to bring about the best results can be found4 ,instead of adding copper sulfate to sewages of high magnesium content satisfactory clarification of the sample can be obtained by mixing it with the alkali hydroxide alone4#ed ,,albuminoid ,,nitrogen4 ,the addition of an alkaline permanganate solution to liquids containing nitrogenous organic matter causes the formation of ammonia1 which can be distilled and determined by ,nesslerization of the distillate4 ,the nitrogen of the ammonia1 thus obtained1 is called albuminoid nitrogen4 ,as the ratio of nitrogenous organic matter to the ammonia obtained by distillation is decidedly variable#fcjge in sewages and other substances containing much nitrogenous organic matter albuminoid nitrogen results on such substances are less accurate#bi than organic 7,kjeldahl7 nitrogen4 ,therefore in sewage work1 including analysis of influents and effluents of purification plants and the water of highly polluted streams1 it is recommended that determinations of organic nitrogen be substituted for determinations of albuminoid nitrogen4 ,for ground waters and surface waters containing but little pollution1 the albuminoid nitrogen is approximately one-half the organic nitrogen2 accordingly the continuance of albuminoid nitrogen determinations for this class of work is approved4 ,reagents4--,alkaline potassium permanganate4 ,pour #a1bjj cc4 of distilled water into a porcelain dish holding #b1ejj cc41 boil #aj minutes1 and turn off the gas4 ,add #af grams of ,c4 ,p4 potassium permanganate and stir until solution is complete4 ,then add #hjj cc4 of #ej per cent clarified solution of potassium hydroxide or an equivalent amount of sodium hydroxide and enough distilled water to fill the dish4 ,boil down to #b1jjj cc4 ,test this solution for ammonia by making a blank determination4 ,correct determinations by the amount of this blank4 ,procedure4--,after the collection of the distillate for ammonia nitrogen described on page #ae add #ej cc4 7or more if necessary to insure the complete oxidation of the organic matter7 of alkaline potassium permanganate and continue the distillation until at least four portions1 and preferably five portions1 of #ej cc4 each1 of distillate have been collected in separate tubes4 ,determine the albuminoid nitrogen in the distillate by ,nesslerization4 ,if the albuminoid nitrogen is known to be high it is convenient to collect the distillate in a #bjj cc4 flask and to ,nesslerize an aliquot part of it4 ,dissolved albuminoid nitrogen may be determined in a sample from which suspended matter has been removed by filtration either through filter paper or through a ,berkefeld filter4 ,suspended albuminoid nitrogen is the difference between the total and the dissolved albuminoid nitrogen4 ,,organic ,,nitrogen4#bd;b#figagfhd ,procedure for water4--,boil #ejj cc4 of the sample in a round-bottomed flask to remove ammonia nitrogen4 ,this usually causes the loss of #bjj cc4 of the sample1 which may be collected for the determination of ammonia nitrogen4 ,add #e cc4 of nitrogen-free concentrated sulfuric acid and a small piece of ignited pumice4 ,mix by shaking and place over a flame under a hood4 ,digest until copious fumes of sulfuric acid are given off and the liquid finally becomes colorless or pale straw color4 ,remove from the flame1 and add potassium permanganate crystals in small portions until a heavy green precipitate persists in the liquid4 ,cool4 ,dilute to about #cjj cc4 with ammonia-free water4 ,make alkaline with #aj per cent ammonia-free sodium hydroxide4 ,distill the ammonia1 collect the distillate in ,nessler tubes1 ,nesslerize1 and compare with standards as described 7pp4 #af-ah74 ,first procedure for sewage#gf4--;,distill the ammonia nitrogen directly from #ajj cc4 or less of the sample1 diluted to #ejj cc4 with nitrogen-free water4 ,collect the distillate and determine the ammonia nitrogen in it4 ,add #e cc4 of nitrogen-free sulfuric acid and #a cc4 of #aj per cent nitrogen-free copper sulfate1 and digest the liquid for half an hour after it has become colorless or pale straw color4 ,add #j4e gram of potassium permanganate crystals to the hot acid solution1 and dilute to #ejj cc4 with ammonia-free water4 ,dilute #aj cc4 or more of this liquid1 in a ,kjeldahl distilling flask1 to about #cjj cc4 with ammonia-free water4 ,make alkaline with #aj per cent sodium hydroxide1 distill1 and ,nesslerize4 ,with some samples direct ,nesslerization may be used4 7,see p4 #ai47 ,in this determination care must be taken to digest thoroughly1 to add potassium permanganate to the point of precipitation1 to sample carefully after dilution1 and to add enough sodium hydroxide to insure the separation of the ammonia from the precipitated manganese hydroxide4 ,potassium permanganate should not be added during digestion because it causes loss of nitrogen4 ,second procedure for sewage4--,omit the separation of ammonia nitrogen and determine the ammonia nitrogen and organic nitrogen together4 ,determine the ammonia nitrogen in a separate sample by direct ,nesslerization as described on page #ai4 ,the organic nitrogen is equal to the difference4 ,,nitrite ,,nitrogen4#eafc;a#fdid;c#ajh ,reagents4--#a4 ,sulfanilic acid solution4 ,dissolve #h4jj grams of the purest sulfanilic acid in #a1jjj cc4 of #e ,n acetic acid 7sp4 gr4 #a4jda7 or in #a1jjj cc4 of water containing #ej cc4 of concentrated hydrochloric acid4 ,this is practically a saturated solution4 #b4 -naphthylamine acetate or chloride solution4 ,dissolve #e4jj grams solid -naphthylamine in #a1jjj cc4 of #e ,n acetic acid or in #a1jjj cc4 of water containing #h cc4 of concentrated hydrochloric acid4 ,filter the solution through washed absorbent cotton or an alundum filter4 #c4 ,sodium nitrite stock solution4 ,dissolve #a4a gram silver nitrite in nitrite-free water2 precipitate the silver with sodium chloride solution and dilute the whole to #a liter4 #d4 ,standard sodium nitrite solution4 ,dilute #ajj cc4 of solution #c to #a liter1 then dilute #ej cc4 of this solution to #a liter with sterilized nitrite-free water1 add #a cc4 of chloroform1 and preserve in a sterilized bottle4 ,one cc4 #j4jjje mg4 nitrogen4 #e4 ,fuchsine solution4 #j4a gram per liter4 ,procedure4--,place in a standard ,nessler tube #ej cc4 of the sample1 decolorized if necessary with nitrite-free aluminium hydroxide 7see p4 #db7 or a smaller amount diluted to #ej cc4 ,at the same time prepare in ,nessler tubes a set of standards1 by diluting to #ej cc4 with nitrite-free water1 various amounts of the standard nitrite solution4 ,the following amounts of standard solution are suggested3 #j4j1 #j4a1 #j4b1 #j4d1 #j4g1 #a4j1 #a4d1 #a4g1 #b4j1 and #b4e cc4 ,add #a cc4 of the sulfanilic acid solution and #a cc4 of the -naphthylamine acetate or hydrochloride solution to the sample and to each standard4 ,mix thoroughly and allow to stand #aj minutes2 then compare the sample with the standards4 ,do not allow the sample to stand more than one-half hour before making the comparison4 ,if the color of the sample is deeper than that of the highest standard repeat the test on a diluted sample4 ,if #ej cc4 of the sample is used #j4ja times the number of cc4 of the standard matched equals parts per million of nitrite nitrogen4 ,satisfactory results can be obtained by using either hydrochloric or acetic acid in preparing the test solutions1 but the speed of the reaction is more rapid if acetic acid is used4#aab ,permanent standards may be prepared by matching the nitrite standards with dilutions of the fuchsine solution4 ,fuchsine standards have been found to be sufficiently accurate for waters high in nitrite and for sewage4 ,the standards should be checked once a month and kept out of bright sunlight4 ,,nitrate ,,nitrogen4#afcfijajj ,two methods are recommended for the determination of nitrate nitrogen in water1 sewage1 and sewage effluents4 ,,phenoldisulfonic ,,acid ,,method4#aecb ,reagents4--#a4 ,phenoldisulfonic acid4 ,dissolve #be grams of pure white phenol in #aej cc4 of pure concentrated sulfuric acid4 ,add #ge cc4 of fuming sulfuric acid 7#ae per cent ,,so#c71 stir well1 and heat for #b hours at about #ajj;,c4 #b4 ,potassium hydroxide solution4 ,prepare an approximately #ab ,n solution1 #aj cc4 of which will neutralize about #d cc4 of the phenoldisulfonic acid4 #c4 ,standard nitrate solution4 ,dissolve #j4gb gram of pure recrystallized potassium nitrate in #a liter of distilled water4 ,evaporate cautiously to dryness #aj cc4 of the solution on the water bath4 ,moisten residue quickly and thoroughly with #b cc4 of phenoldisulfonic acid and dilute to #a liter4 ,this is the standard solution1 #a cc4 of which equals #j4jja mg4 of nitrate nitrogen4 #d4 ,standard silver sulfate solution4 ,dissolve #d4d grams of silver sulfate free from nitrate in #a liter of water4 ,one cc4 of this solution is equal to #a mg4 of chloride4 ,procedure4--,the alkalinity1 chloride1 and nitrite content1 and color of the sample must first be determined4 ,if the sample is highly colored decolorize it with freshly precipitated aluminium hydroxide4 ,measure into an evaporating dish #ajj cc4 of the sample1 or if nitrate is very high such volume as will contain about #j4ja mg4 of nitrate nitrogen4 ,add sufficient ,n_/#ej sulfuric acid nearly to neutralize the alkalinity4 ,then add sufficient standard silver sulfate to precipitate all but about #j4a mg4 of chloride4 ,the removal of chloride may be omitted if the sample contains less than #cj parts per million of chloride4 ,heat the mixture to boiling1 add a little aluminium hydroxide1 stir1 filter1 and wash with small amounts of hot water4 ,evaporate the filtrate to dryness1 and add #b cc4 of the phenoldisulfonic acid1 rubbing with a glass rod to insure intimate contact4 ,if the residue becomes packed or appears vitreous because of the presence of much iron1 heat the dish on the water bath for a few minutes4 ,dilute the mixture with distilled water1 and add slowly a strong solution of potassium hydroxide or ammonium hydroxide until the maximum color is developed4 ,transfer the solution to a ,nessler tube1 filtering if necessary4 ,if nitrate is present a yellow color will be formed4 ,compare the color with that of standards#ebee made by adding #b cc4 of strong potassium hydroxide or ammonium hydroxide to various amounts of standard nitrate solution and diluting them to #ej cc4 in ,nessler tubes4 ,the following amounts of standard nitrate solution are suggested3 #j1 #j4e1 #a4j1 #a4e1 #b4j1 #d4j1 #f4j1 #h4j1 #aj4j1 #ae4j1 #bj4j1 and #dj4j cc4 ,these standards may be kept several weeks without deterioration4 ,if #ajj cc4 of water is used the number of cubic centimeters of the standard multiplied by #j4ja is equal to parts per million of nitrate nitrogen4 ,standards that will remain permanent for several years if stored in the dark may be prepared from tripotassium nitrophenoldisulfonate4#e ,if nitrite nitrogen is present in excess of #a part per million it should be oxidized by heating the samples a few minutes with a few drops of hydrogen peroxide free from nitrate repeatedly added#ie or by adding dilute potassium permanganate in the cold until a faint pink coloration appears2 the nitrogen equivalent of the nitrite thus oxidized to nitrate is then subtracted from the final nitrate nitrogen reading4 ,,reduction ,,method4#bdf ,reagents4--#a4 ,sodium or potassium hydroxide solution4 ,dissolve #bej grams of the hydroxide in #a4be liters of distilled water4 ,add several strips of aluminium foil and allow the evolution of hydrogen to continue over night4 ,concentrate the solution to #a liter by boiling4 #b4 ,aluminium foil4 ,use strips of pure aluminium about #aj cm4 long1 #f mm4 wide1 and #j4cc mm4 thick and weighing about #j4e gram4 ,procedure4--,to #ajj cc4 of the sample in a #cjj cc4 casserole add #b cc4 of the hydroxide solution and concentrate by boiling to about #bj cc4 ,pour the contents of the casserole into a test tube about #af cm4 long and #c cm4 in diameter1 or of approximately #ajj cc4 capacity4 ,rinse the casserole several times with nitrogen-free water and add the rinse water to the liquid already in the tube1 thus making the contents of the tube approximately #ge cc4 ,add a strip of aluminium foil4 ,close the tube by means of a rubber stopper through which passes a bent glass tube about #e mm4 in diameter4 ,put the shorter arm of the tube flush with the lower side of the rubber stopper and let the longer arm extend below the surface of distilled water in another test tube4 ,this apparatus serves as a trap through which the evolved hydrogen escapes freely4 ,the small amount of ammonia escaping into the trap may be neglected4 ,allow the action to proceed for a minimum period of four hours or over night4 ,pour the contents of the tube into a distilling flask1 dilute with #bej cc4 of ammonia-free water1 distill1 collect the distillate in ,nessler tubes1 and ,nesslerize4 ,if the nitrate content is high collect the distillate in a #bjj cc4 flask and ,nesslerize an aliquot part4 ,if the supernatant liquid in the reduction tube is clear and colorless the solution may be diluted to a definite volume and an aliquot part ,nesslerized without distillation4 ,,total ,,nitrogen4#ic ,in sewage work it is frequently of assistance to know the total nitrogen content4 ,this is ordinarily computed by adding together the organic1 ammonia1 nitrite1 and nitrate nitrogen1 each of which is determined as already described4 ,,oxygen ,,consumed4#bdfghd;a#heid;f#ajaajb ,oxygen consumed means the oxygen that the oxidizable compounds of sewage and water consume when treated in an acid solution with potassium permanganate4 ,the expression is synonymous with oxygen required1 oxygen absorbed1 and oxygen-consuming capacity4 ,it should not be confused with biochemical oxygen demand4 ,as the carbon1 not the nitrogen1 in organic matter is oxidized by potassium permanganate1 oxygen consumed is considered by some an indication of the amount of carbonaceous organic matter present4 ,the determination indicates1 however1 only part of the carbon1 the proportion varying in different samples because the carbon in nitrogenous matter is not so readily oxidized as that in carbonaceous organic matter4 ,furthermore1 it does not directly differentiate the carbon present in unstable organic matter from that in fairly stable organic matter1 such as is sometimes referred to as residual humus matter4 ,as nitrite nitrogen1 ferrous iron1 sulfide1 and other oxidizable mineral substances reduce potassium permanganate1 corrections for them should be made in the determination4 ,,recommended ,,method4 ,reagents4--#a4 ,dilute sulfuric acid4 ,dilute #a part of concentrated sulfuric acid with #c parts of distilled water and free the solution from oxidizable matter by adding potassium permanganate until a faint pink color persists after the solution has stood several hours4 #b4 ,standard ammonium oxalate4 ,dissolve #j4hhh gram of the pure salt in #a liter of distilled water4 ,one cc4 is equivalent to #j4a mg4 of oxygen4 ,an equivalent quantity of oxalic acid or sodium oxalate may be used4 #c4 ,standard potassium permanganate4 ,dissolve #j4d gram of the crystallized salt in #a liter of distilled water4 ,add #aj cc4 of the dilute sulfuric acid and #aj cc4 of this solution of potassium permanganate to #ajj cc4 of distilled water1 and digest #cj minutes4 ,add #aj cc4 of the ammonium oxalate solution1 and then add potassium permanganate till a pink coloration appears4 ,this destroys the oxygen-consuming capacity of the water used4 ,now add another #aj cc4 of ammonium oxalate solution and titrate with potassium permanganate4 ,adjust the potassium permanganate solution so that #a cc4 is equivalent to #a cc4 of ammonium oxalate solution or #j4a mg4 of available oxygen4 ,acid digestion4--,place in a flask #ajj cc4 of the water1 or1 if the water is of high organic content1 a smaller portion diluted to #ajj cc4 ,add #aj cc4 of sulfuric acid solution and #aj cc4 of standard potassium permanganate and digest the liquid exactly #cj minutes in a bath of boiling water the level of which is kept above the level of the contents of the flask4#gjga;a ,if the quantity of permanganate is insufficient for complete oxidation repeat the digestion with a larger quantity2 at least #e cc4 excess of the standard permanganate should be present when the ammonium oxalate solution is added4 ,remove the flask1 add #aj cc4 of the ammonium oxalate solution1 and titrate with the standard permanganate until a faint but distinct color is obtained4 ,if #ajj cc4 of water is used the number of cubic centimeters of potassium permanganate solution in excess of the number of cubic centimeters of ammonium oxalate solution is equal to parts per million of oxygen consumed4 ,if oxidizable mineral substances1 such as ferrous iron1 sulfide1 or nitrite1 are present in the sample corrections should be applied as accurately as possible by suitable procedures4 ,direct titration of the acidified sample in the cold1 using a three-minute period of digestion1 serves this purpose quite well for polluted surface waters and fairly well for purified sewage effluents4 ,few raw sewages containing no trade wastes need such a correction1 but raw sewages containing 8pickling0 liquors do need it4 ,if the sample contains both oxidizable mineral compounds and gaseous organic substances the latter should be driven off by heat and the sample allowed to cool before applying this test for the correction factor4 ,if such corrections are made the fact should be stated with the amount of correction4 ,period and temperature of digestion4--,as the practice in regard to the period and temperature of digestion has varied widely it is difficult to compare the results obtained at one laboratory with those obtained at another4 ,none of the methods gives absolute results4 ,they are all relative#bfbieg at best4 ,digesting #cj minutes at the boiling temperature is herein designated the recommended method4 ,if samples are analyzed by any other method the method should be noted1 and1 representative results by the standard method should be placed on record for purposes of comparison4 ,,other ,,methods4 ,additional reagents4--#a4 ,potassium iodide solution4 ,ten per cent solution1 free from iodate4 #b4 ,standard sodium thiosulfate4 ,dissolve #a4j gram of the pure crystallized salt in #a liter of distilled water4 ,standardize this solution against the standard potassium permanganate4 ,as the thiosulfate solution does not keep well determine its actual strength at frequent intervals4 #c4 ,starch indicator4 ,prepare as directed in the section on dissolved oxygen 7pp4 #fe-ff74 #d4 ,sodium hydroxide solution4 ,dissolve #a part of pure sodium hydroxide in #b parts of distilled water4 ,certain widely practiced deviations from the standard procedure just described are noted in the following paragraphs4 #a4 ,heat the acidified sample to boiling1 add the permanganate solution1 and digest for two minutes#af at boiling temperature4 ,this procedure is facilitated by agitating the liquid constantly with a small current of air to guard against bumping4 #b4 ,same method as ,no4 #a except that the period of digestion is five minutes4#aba;a #c4 ,same method as ,no4 #b except that the permanganate solution is added to the acidified sample when cold1 and digestion is continued five minutes after the sample reaches the boiling point4 ,the advantage of this method is that there is included the oxygen-consuming power of the volatile matter present in some sewages and sewage effluents1 which is driven off by heat and thus escapes when the test is made in accordance with procedures #a and #b4 #d4 ,same method as ,no4 #c except that the period of digestion is #aj minutes4#fcfh;c #e4 ,digestion of the sample after the acid and permanganate solutions are added is carried out abroad1 especially in ,england1 at approximately the room temperature1#bd;a#fi;a#id;f#ajj;a apparently to guard against decomposition#ag of permanganate in the presence of high chloride1 for periods of three minutes1 fifteen minutes1 and four hours2 many observers record the oxygen consumed after all three periods1 while some record the result only for the four-hour period4 ,at the end of the period of digestion1 add #j4e cc4 of potassium iodide solution to discharge the pink color2 mix2 titrate the liberated iodine with thiosulfate until the yellow color is nearly destroyed1 then add a few drops of starch solution and continue titration until the blue color is just discharged4 ,the number of cubic centimeters of potassium permanganate solution in excess of the number of cubic centimeters of sodium thiosulfate solution is equal to parts per million of oxygen consumed4 #f4 ,digestion in alkaline solution#ajd is preferable to digestion in acid solution for brines or waters high in chlorine4 ,place in a flask #ajj cc4 of the sample1 or if it is of high organic content a smaller portion diluted to #ajj cc4 ,add #j4e cc4 of sodium hydroxide solution and #aj cc4 of standard potassium permanganate and digest exactly #cj minutes4 ,remove the flask1 add #e cc4 of sulfuric acid and #aj cc4 of the standard ammonium oxalate1 and titrate with the standard potassium permanganate as in the acid digestion4 ,,residue ,,on ,,evaporation4 ,,total ,,residue4#af ,ignite and weigh a clean platinum dish1 and measure into it #ajj cc4 of the thoroughly shaken sample4 ,evaporate to dryness on a water bath4 ,then heat the dish in an oven at #ajc ,c4 or #ahj ,c4 for one hour4 ,cool in a desiccator and weigh4 ,the temperature of drying should be mentioned in the report4 ,the increase in weight gives the total solids or residue on evaporation4 ,if #ajj cc4 of the sample was taken this weight expressed in milligrams and multiplied by #aj is equal to parts per million of residue on evaporation4 ,the residue from waters low in organic matter but relatively high in iron may be used1 as a matter of convenience1 for the determination of iron4 ,,fixed ,,residue ,,and ,,loss ,,on ,,ignition4#acif ,the residue from sewages and waters high in organic matter may be ignited to burn off the organic matter1 which1 with some volatile inorganic matter1 constitutes the loss on ignition4 ,procedure4--,ignite the residue in the platinum dish at a low red heat4 ,if great accuracy is desired this should be done in an electric muffle furnace or in a radiator1 which consists of a platinum or a nickel dish large enough to allow an air space of about half an inch between it and the dish within it1 the inner dish being supported by a triangle of platinum wire laid on the bottom of the outer dish4 ,a disc of platinum or nickel foil large enough to cover the outer dish is suspended over the inner dish to radiate the heat into it4 ,the larger dish is heated to bright redness until the residue is white or nearly so4 ,allow the dish to cool1 and moisten the residue with a few drops of distilled water4 ,dry the residue in the oven1 cool in a desiccator1 and weigh4 ,the fixed residue on evaporation is the difference between this weight and the weight of the dish4 ,the loss on ignition is the difference between the total residue on evaporation and the fixed residue on evaporation4 ,if the odor and color on ignition of some residues give helpful clues to the character of the organic matter record them4 ,,suspended ,,matter4#efaaj ,,determination ,,with ,,gooch ,,crucible4 ,reagent4--,prepare a dilute cream of asbestos fibre which has been finely shredded1 thoroughly ignited1 treated with strong hydrochloric acid for at least #ab hours1 and washed with distilled water till free from acid4 ,procedure4--#a4 ,prepare a mat of the asbestos fibre #a_/af inch thick in a ,gooch crucible4 ,dry it in an oven at #ajc or #ahj ,c41 cool and weigh4 ,filter #a1jjj cc4 of samples having a turbidity of #ej parts per million or less4 ,if the turbidity is higher use sufficient water to obtain #ej to #ajj mg4 of suspended matter4 ,dry for one hour at #ajc or #ahj ,c41 cool and weigh4 ,report the temperature at which the residue was dried4 ,if #a1jjj cc4 is filtered the increase in weight expressed in milligrams is equal to parts per million of suspended matter4 ,,determination ,,by ,,filtration4 ,the difference between the total solids in filtered and unfiltered portions of a sample may be used as a basis for calculating suspended matter4 ,,determination ,,of ,,volume4 ,the determination of the volume#ifi;b of suspended matter in sewages has received considerable attention abroad4 ,imhoff recommends the use of conical glass vessels holding #a liter with the lower portions graduated in cubic centimeters4 ,others recommend centrifuges with sediment tubes4 ,,fixed ,,residue ,,and ,,loss ,,on ,,ignition4 ,treat the total residue from a filtered sample in the same manner as described for the total residue1 and obtain the loss on ignition due to dissolved matter1 and by difference the loss on ignition due to suspended matter4 ,,hardness4#id;e ,a water containing certain mineral constituents in solution1 chiefly calcium and magnesium1 which form insoluble compounds with soap1 is said to be hard4 ,carbon dioxide in water increases the solubility of calcium and magnesium carbonates1 forming bicarbonate4 ,if carbon dioxide is removed from the water by boiling the bicarbonate is decomposed and calcium and magnesium are partly precipitated4 ,the proportion of calcium or magnesium carbonate that a water can hold in solution depends on the concentration of carbon dioxide1 which in turn depends on the temperature of the water and the proportion of carbon dioxide in the atmosphere with which the water has been in contact4 ,consequently1 when the carbon dioxide is removed from the water by boiling or otherwise the carbonates of calcium and magnesium are partly1 but not completely1 precipitated1 and the hardness of the water is thus diminished and the water is softened to the extent to which these substances are precipitated4 ,the hardness thus removed is called temporary hardness4 ,the hardness which still remains after boiling is due mainly to calcium and magnesium in equilibrium with sulfate1 chloride1 and nitrate1 and residual carbonate1 and it is called permanent hardness4 ,non-carbonate hardness is the hardness caused by sulfates1 chlorides1 and nitrates of calcium1 magnesium1 iron1 and other metals that form insoluble soaps4 ,,total ,,hardness ,,by ,,calculation4 ,the most accurate method of ascertaining total hardness is to compute it from the results of determinations of calcium and magnesium in the sample4 7,see methods1 pp4 #eg-eh47 ,iron and other metals must be included in the calculation if they are present in significant amounts4 ,total hardness as ,ca,c,o#c equals #b4e ,ca plus #d4a ,mg4 ,,total ,,hardness ,,by ,,soap ,,method4#aba;b ,the determination of hardness by the soap method roughly approximates the amount of calcium and magnesium in a water1 though it actually measures the soap-consuming power of the water4 ,reagents4--#a4 ,standard calcium chloride solution4 ,dissolve #j4b gram of pure calcite 7calcium carbonate7 in a little dilute hydrochloric acid1 being careful to avoid loss of solution by spattering4 ,evaporate the solution to dryness several times with distilled water to expel excess of acid4 ,dissolve the residue in distilled water and dilute the solution to #a liter4 ,one cc4 of this dilution is equivalent to #j4b mg4 of calcium carbonate4 #b4 ,standard soap solution4 ,dissolve #ajj grams of dry white ,castile soap in #a liter of #hj per cent alcohol1 and allow this solution to stand several days before standardizing4 ,pure potassium oleate made from lead plaster and potassium carbonate may be used in place of ,castile soap4 ,first method of standardization4--,dilute #bj cc4 of the calcium chloride solution in a #bej cc4 glass-stoppered bottle to #ej cc4 with distilled water which has been recently boiled and cooled4 ,add soap solution from a burette1 #j4b or #j4c cc4 at a time1 shaking the bottle vigorously after each addition until a lather remains unbroken for five minutes over the entire surface of the water while the bottle lies on its side4 ,then adjust the strength of the stock solution with #gj per cent alcohol so that the resulting diluted soap solution will give a permanent lather when #f4dj cc4 of it is properly added to #bj cc4 of standard calcium chloride solution diluted to #ej cc4 ,usually #ge to #ajj cc4 of the stock soap solution is required to make #a liter of the standard soap solution4 ,the quantity of calcium carbonate equivalent to each cubic centimeter of the standard soap solution consumed in the titration is indicated in ,table #f4 ,table #f4--,,total ,,hardness ,,in ,,parts ,,per ,,million ,,of ,ca,c,o#c ,,for ,,each ,,tenth ,,of ,a ,,cubic ,,centimeter ,,of ,,soap ,,solution ,,when #ej ,,cc4 ,,of ,,the ,,sample ,,is ,,titrated4 ,cubic centimeters #j4j4 #j4a4 #j4b4 #j4c4 #j4d4 #j4e4 #j4f4 #j4g4 #j4h4 #j4i4 of soap solution4 #j4j #j4j #a4f #c4b #a4j #d4h #f4c #g4i #i4e #aa4a #ab4g #ad4c #ae4f #af4i #ah4b #b4j #ai4e #bj4h #bb4a #bc4d #bd4g #bf4j #bg4c #bh4f #bi4i #ca4b #c4j #cb4e #cc4h #ce4a #cf4d #cg4g #ch4j #dj4c #da4f #db4i #dd4c #d4j #de4g #dg4a #dh4f #ej4j #ea4d #eb4i #ed4c #ee4g #eg4a #eh4f #e4j #fj4j #fa4d #fb4i #fd4c #fe4g #fg4a #fh4f #gj4j #ga4d #gb4i #f4j #gd4c #ge4g #gg4a #gh4f #hj4j #ha4d #hb4i #hd4c #he4g #hg4a #g4j #hh4f #ij4j #ia4d #ib4i #id4c #ie4g #ig4a #ih4fajj4jaja4e ,this table does not provide for the use of so large volume of soap solution for a single determination as former ones because the end-point becomes somewhat obscured in the presence of magnesium if more than #g cc4 is used4 ,second method of standardization4--,dilute #ajj cc4 of the stock soap solution to #a liter with #gj per cent alcohol4 ,this dilute solution should be of such strength that approximately #f4d cc4 of it will give a permanent lather when #bj cc4 of standard calcium chloride solution diluted to #ej cc4 with distilled water is titrated with it4 ,determine the amount of soap solution required to give a permanent lather with #ej cc4 of distilled water and with #e1 #aj1 #ae1 and #bj cc4 of standard calcium chloride solution diluted to #ej cc4 with distilled water4 ,finally plot on cross-section paper a curve showing the relation of various quantities of soap solution to corresponding quantities of standard calcium carbonate solution and therefore to parts per million of hardness4 ,procedure4--,measure #ej cc4 of the water into a #bej cc4 bottle and add to it soap solution in small quantities in precisely the same manner as described under the standardization of the soap solution4 ,from the number of cubic centimeters of soap solution used obtain from ,table #f or from the plotted curve the total hardness of the water in parts per million of calcium carbonate4 ,to avoid mistaking the false or magnesium end-point for the true one#ce when adding the soap solution to waters containing magnesium salts1 read the burette after the titration is apparently finished1 and add about #j4e cc4 more of soap solution4 ,if the end-point was due to magnesium the lather will disappear4 ,soap solution must then be added until the true end-point is reached4 ,usually the false lather persists for less than five minutes4 ,if more than #g cc4 of soap solution is required for #ej cc4 of the water take less of the sample and dilute it to #ej cc4 with distilled water which has been recently boiled and cooled4 ,this step reduces somewhat the disturbing influence of magnesium1#ajg;a which consumes more soap than an equivalent weight of calcium4 ,at best the soap method is not a precise test on account of the different relative amounts of calcium and magnesium in different waters4 ,for hard waters1 especially in connection with processes for purification and softening1 it is advised that this method be not exclusively used4 ,if the same water is frequently analyzed it may be of assistance to standardize the soap solution against a mixture of calcium and magnesium salts1 the relative proportions of which approximate those found in the water4 ,the strength of the soap solution should be determined from time to time1 to make sure that it has not materially changed4 ,record all results in parts per million of calcium carbonate4 ,one ,english degree of hardness1 ,clark's scale1 is equivalent to #a grain per ,imperial gallon of calcium carbonate4 ,one ,french degree of hardness is equivalent to #a part per #ajj1jjj of calcium carbonate4 ,one ,german degree of hardness is equivalent to #a part per #ajj1jjj of calcium oxide1 and multiplied by #ag4i gives parts per million of calcium carbonate4 ,the relations of these various scales are indicated in ,table #g4 ,table #g4--;,,conversion ,,table ,,for ,,hardness4 ,unit4 ,equivalent4 ,parts per ,clark ,french ,german million4 degrees4 degrees4 degrees4 ,one part per million #a4jj #j4jg #j4aj #j4jef ,one ,clark degree #ad4c #a4jj #a4dc 4#hj ,one ,french degree #aj4j 4#gj #a4jj 4#ef ,one ,german degree #ag4i #a4bd #a4gh #a4jj ,,total ,,hardness ,,by ,,soda ,,reagent ,,method4#dggdhaid;d ,add standard sulfuric acid to #bjj cc4 of the sample until the alkalinity is neutralized4 7,see ,procedure with methyl orange1 p4 #cg47 ,then apply the non-carbonate hardness method 7pp4 #cd-ce74 ,this method gives fairly satisfactory estimates of total hardness of hard waters4 ,,temporary ,,hardness ,,by ,,titration ,,with ,,acid4 ,determine the alkalinity in presence of methyl orange 7see p4 #cg7 in the original sample and also in the sample after boiling1 cooling1 restoring to the original volume with boiled distilled water1 and filtering4 ,the difference between the two1 if any1 is the temporary hardness4 ,this is the most accurate method of determining the temporary hardness of ordinary waters4 ,iron bicarbonate is included as a part of the temporary hardness4 ,,non-,,carbonate ,,hardness ,,by ,,soda ,,reagent ,,method4#dggdhaid;d ,the use of soda reagent does not avoid entirely the error due to solubility of the salts of calcium and magnesium2 consequently1 if much depends on the results1 as in water softening1 gravimetric determinations of the calcium and magnesium that remain in solution should be made and a correction should be applied for those amounts4 ,reagent4--,prepare soda reagent from equal parts of sodium hydroxide and sodium carbonate4 ,it should be approximately tenth normal4 ,procedure4--,measure #bjj cc4 of the sample and #bjj cc4 of distilled water into #ejj cc4 ,jena or similar glass ,erlenmeyer flasks4 ,treat the contents of each flask in the following manner4 ,boil #ae minutes to expel free carbon dioxide4 ,add #be cc4 of soda reagent4 ,boil #aj minutes1 cool1 rinse into #bjj cc4 graduated flasks1 and dilute to #bjj cc4 with boiled distilled water4 ,filter1 rejecting the first #ej cc41 and titrate #ej cc4 of each filtrate with ,n_/#ej sulfuric acid in the presence of methyl orange or erythrosine indicator4 ,the non-carbonate hardness in parts per million of calcium carbonate is equal to #bj times the difference between the number of cubic centimeters of sulfuric acid required for the soda reagent in distilled water and the number of cubic centimeters of ,n_/#ej sulfuric acid required for the soda reagent in the sample4 ,water naturally containing bicarbonate and carbonate in excess of calcium and magnesium requires a larger amount of acid to neutralize the sample after it has been treated than is required to neutralize the volume of soda reagent originally added4 7,see p4 #ci47 ,,non-,,carbonate ,,hardness ,,by ,,soap ,,method4 ,non-carbonate hardness may be calculated for waters which are soft or moderately hard in a fairly satisfactory manner by deducting the total alkalinity from the total hardness by the soap method 7pp4 #ca-cd74 ,for waters that are very hard1 and particularly those that contain much magnesium1 this method is not advised4 ,,alkalinity4#aaahdgig ,the alkalinity of a natural water represents its content of carbonate1 bicarbonate1 borate1 silicate1 phosphate1 and hydroxide4 ,alkalinity is determined by neutralization with standard sulfuric acid or potassium bisulfate in the presence of phenolphthalein and either methyl orange1 erythrosine1 or lacmoid as indicators4 ,methyl orange may be used except in waters containing aluminium sulfate or iron sulfate4 ,the relations between estimates in presence of these indicators and the carbonate1 bicarbonate1 and hydroxide radicles are indicated in ,table #h4 ,the alkalinity of carbonates in the presence of phenolphthalein is different from that in the presence of methyl orange1 partly because of loss of carbon dioxide and partly because of defects in phenolphthalein as an indicator in such conditions4 ,table #h4--,,relations ,,between ,,alkalinity ,,to ,,phenolphthalein ,,and ,,that ,,to ,,methyl ,,orange1 ,,erythrosine1 ,,or ,,lacmoid1 ,,in ,,presence ,,of ,,bicarbonate1 ,,carbonate1 ,,and ,,hydroxide4 ,result of ,value of radicle expressed in terms of calcium titration4,c carbonate4 ,bicarbonate4 ,carbonate4 ,hydroxide4 ,p #j ,t #j #j ,p #a_/b,t ,t #b,p #b,p #j ,p #a_/b,t #j #b,p #j ,p #a_/b,t #j #b7,t ,p7 #b,p ,t ,p ,t #j #j ,t ,footnote ,c3 ,t ,total alkalinity in presence of methyl orange1 erythrosine1 or lacmoid4 ,p ,alkalinity in presence of phenolphthalein4 ,reagents4--#a4 ,sulfuric acid or potassium bisulfate4 ,a ,n_/#ej solution4 #b4 ,phenolphthalein indicator4 ,dissolve #e grams of a good quality of phenolphthalein in #a liter of #ej per cent alcohol4 ,neutralize with ,n_/#aj potassium hydroxide4 ,the alcohol should be diluted with boiled distilled water4 #c4 ,methyl orange indicator4 ,dissolve #j4e gram of a good grade of methyl orange in #a liter of distilled water4 ,keep the solution in the dark4 #d4 ,lacmoid indicator4 ,dissolve #b4j grams of lacmoid in #a liter of #ej per cent alcohol4 ,dilute the alcohol with freshly boiled distilled water4 #e4 ,erythrosine indicator4 ,dissolve #j4e gram of erythrosine 7the sodium salt7 in #a liter of freshly boiled distilled water4 ,,procedure ,,with ,,phenolphthalein4 ,add #d drops of phenolphthalein indicator to #ej or #ajj cc4 of the sample in a white porcelain casserole or an ,erlenmeyer flask over a white surface4 ,if the solution becomes colored1 hydroxide or normal carbonate is present4 ,add ,n_/#ej sulfuric acid from a burette until the coloration disappears4 ,the phenolphthalein alkalinity in parts per million of calcium carbonate is equal to the number of cubic centimeters of ,n_/#ej sulfuric acid used multiplied by #bj if #ej cc4 of the sample was used1 or by #aj if #ajj cc4 was used4 ,,procedure ,,with ,,methyl ,,orange4 ,add #b drops of methyl orange indicator to #ej or #ajj cc4 of the sample1 or to the solution to which phenolphthalein has been added1 in a white porcelain casserole or an ,erlenmeyer flask over a white surface4 ,if the solution becomes yellow1 hydroxide1 normal carbonate1 or bicarbonate is present4 ,add ,n_/#ej sulfuric acid from a burette until the faintest pink coloration appears4 ,the methyl orange alkalinity in parts per million of calcium carbonate is equal to the total number of cubic centimeters of ,n_/#ej sulfuric acid used multiplied by #bj if #ej cc4 of the sample was used1 or by #aj if #ajj cc4 was used4 ,,procedure ,,with ,,lacmoid4 ,add #d drops of lacmoid indicator to #ej or #ajj cc4 of the sample in a porcelain casserole or an ,erlenmeyer flask4 ,add ,n_/#ej sulfuric acid from a burette until within #a or #b cc4 of the amount necessary for neutralization has been added4 ,heat the solution until bubbles of steam begin to break at the surface4 ,remove the dish from the source of heat and continue the titration until a drop of the acid striking the surface of the liquid and sinking to the bottom of the vessel produces no change in the uniform reddish or purple color of the solution4 ,the calculation is the same as for phenolphthalein alkalinity4 ,,procedure ,,with ,,erythrosine4 ,add #e cc4 of neutral chloroform and #a cc4 of erythrosine indicator to #ej or #ajj cc4 of the sample in a #bej cc4 clear glass-stoppered bottle4 ,if the chloroform becomes rose colored on shaking1 hydroxide1 bicarbonate1 or normal carbonate is present4 ,add ,n_/#ej sulfuric acid from a burette until the chloroform becomes colorless4 ,a white surface behind the bottle facilitates detection of a trace of color as the end-point is approached4 ,the calculation is the same as with phenolphthalein alkalinity4 ,,bicarbonate4 ,bicarbonate is present if the alkalinity to phenolphthalein is less than one-half the alkalinity to methyl orange1 erythrosine1 or lacmoid4 ,the alkalinity to methyl orange1 erythrosine1 or lacmoid is due entirely to bicarbonate if there is no phenolphthalein alkalinity4 ,if there is phenolphthalein alkalinity the bicarbonate1 in terms of calcium carbonate1 is equal to the methyl orange1 erythrosine1 or lacmoid alkalinity minus twice the phenolphthalein alkalinity4 ,bicarbonate1 carbon dioxide as bicarbonate1 and half-bound carbon dioxide can be calculated as follows3 ,bicarbonate 7,,hco#c7 #a4bb times the bicarbonate expressed in terms of calcium carbonate4 ,carbon dioxide 7,,co#b7 as bicarbonate #j4hh times the bicarbonate expressed in terms of calcium carbonate4 ,half-bound carbon dioxide 7,,co#b7 #j4dd times the bicarbonate expressed in terms of calcium carbonate4 ,,normal ,,carbonate4#bjid ,normal carbonate is present if the alkalinity to phenolphthalein is greater than zero but less than the alkalinity to methyl orange1 erythrosine1 or lacmoid4 ,if the phenolphthalein alkalinity is exactly equal to one-half the methyl orange1 erythrosine1 or lacmoid alkalinity the alkalinity is due entirely to normal carbonate4 ,if the phenolphthalein alkalinity is less than one-half the methyl orange1 erythrosine1 or lacmoid alkalinity normal carbonate expressed in terms of calcium carbonate is equal to twice the phenolphthalein alkalinity4 ,if the phenolphthalein alkalinity is greater than one-half the methyl orange1 erythrosine1 or lacmoid alkalinity the normal carbonate is equal to twice the difference between the methyl orange1 erythrosine1 or lacmoid alkalinity and the phenolphthalein alkalinity4 ,the carbonate1 carbon dioxide as carbonate1 and bound carbon dioxide can be calculated as follows3 ,carbonate 7,,co#c7 #j4f times the normal carbonate expressed in terms of calcium carbonate4 ,carbon dioxide as carbonate 7,,co#b7 #j4dd times the normal carbonate expressed in terms of calcium carbonate4 ,bound carbon dioxide 7,,co#b7 is the sum of the carbon dioxide as carbonate and one-half that as bicarbonate4 ,,hydroxide4#bjid ,if hydroxide1 or caustic alkalinity1 is present the alkalinity to phenolphthalein is greater than one-half the alkalinity to methyl orange1 erythrosine1 or lacmoid2 the alkalinity is due entirely to hydroxide if the phenolphthalein alkalinity is equal to the methyl orange1 erythrosine1 or lacmoid alkalinity4 ,if the phenolphthalein alkalinity is more than half and less than all the methyl orange1 erythrosine1 or lacmoid alkalinity1 hydroxide1 expressed in terms of calcium carbonate1 is equal to twice the phenolphthalein alkalinity minus the methyl orange1 erythrosine1 or lacmoid alkalinity4 ,,alkali ,,carbonates4 ,waters which contain sodium or potassium carbonates or bicarbonates contain all of their calcium and magnesium as carbonates or bicarbonates4 ,that is1 they possess no non-carbonate hardness 7sulfates1 nitrates or chlorides of calcium and magnesium74 ,the most accurate method is to determine the total alkalinity by titration with ,n_/#ej sulfuric acid1 using methyl orange1 erythrosine1 or lacmoid as an indicator2 then determine the calcium and magnesium content2 and subtract from the total alkalinity the computed alkalinity due to the calcium and magnesium expressed in terms of calcium carbonate4 ,the remainder is the alkalinity due to carbonates and bicarbonates of sodium and potassium4 ,this determination may also be made by applying the method1 for non-carbonate hardness with soda reagent 7see p4 #ce71 and by noting the excess of acid required to neutralize the alkaline carbonates originally present4 ,with present information as to solubilities of the normal carbonates of calcium and magnesium1 it is difficult in their presence to measure slight quantities of carbonates of sodium or potassium4 ,,acidity4#bd;d#cg ,waters may have an acid reaction because of the presence of free carbon dioxide1 mineral acids1 or some of their salts1 especially those of iron and aluminium4 ,reagents4--#a4 ,n_/#ej sodium carbonate4 ,dissolve #a4jf grams of anhydrous sodium carbonate in #a liter of boiled distilled water that has been cooled in an atmosphere free from carbon dioxide4 ,preserve this solution in bottles of resistant glass protected from the air by tubes filled with soda-lime4 ,one cc4 is equivalent to #a mg4 of ,ca,c,o#c4 #b4 ,n_/#bb sodium carbonate4 ,dissolve #b4da grams of anhydrous sodium carbonate in #a liter of boiled distilled water that has been cooled in an atmosphere free from carbon dioxide4 ,preserve this solution in bottles of resistant glass protected from the air by tubes filled with soda-lime4 ,one cc4 is equivalent to #a mg4 of ,,co#b4 #c4 ,phenolphthalein indicator 7see p4 #cf74 #d4 ,methyl orange indicator 7see p4 #cf74 ,,total ,,acidity4 ,procedure4--,add #d drops of phenolphthalein indicator to #ej or #ajj cc4 of the sample in a white porcelain casserole or an ,erlenmeyer flask over a white surface4 ,add ,n_/#ej sodium carbonate until the solution turns pink4 ,the total acidity in parts per million of calcium carbonate is equal to the number of cubic centimeters of ,n_/#ej sodium carbonate used multiplied by #bj if #ej cc4 of the sample was used1 or by #aj if #ajj cc4 was used4 ,,free ,,carbon ,,dioxide4#bjbcfahghhid;a#aah ,carbon dioxide may exist in water in three forms--free carbon dioxide1 bicarbonate 7pp4 #cg-ch71 and carbonate 7p4 #ch74 ,one-half the carbon dioxide as bicarbonate is known as the half-bound carbon dioxide4 ,the carbon dioxide as carbonate plus one-half that as bicarbonate is known as the bound carbon dioxide4 ,procedure4--,pour #ajj cc4 of the sample into a tall narrow vessel1 preferably a #ajj cc4 ,nessler tube4 ,add #aj drops of phenolphthalein indicator1 and titrate rapidly with ,n_/#bb sodium carbonate1 stirring gently1 until a faint but permanent pink color is produced4 ,the free carbon dioxide 7,,co#b7 in parts per million is equal to #aj times the number of cubic centimeters of ,n_/#bb sodium carbonate used4 ,because of the ease with which free carbon dioxide escapes from water1 particularly when the gas is present in large amount1 a special sample should be collected for this determination1 which should preferably be made at the time of collection4 ,if the analysis cannot be made at the time of collection approximate results with water not too high in free carbon dioxide may be obtained on samples collected in bottles completely filled so as to leave no air space under the stopper4 ,bottled samples should be kept1 until tested1 at a temperature lower than that of the water when collected4 ,if mineral acids or certain salts are present correction must be made4 ,at best1 the results of the titration are uncertain because the proper end-point for correct results differs in color with different types of water4 ,,free ,,mineral ,,acids4 ,procedure4--,add #b drops of methyl orange indicator to #ej or #ajj cc4 of the sample in a white porcelain casserole or an ,erlenmeyer flask over a white surface4 ,add ,n_/#ej sodium carbonate from a burette until the pink coloration of the solution disappears4 ,the acidity due to free mineral acids1 expressed in terms of calcium carbonate1 is equal to the number of cubic centimeters of ,n_/#ej sodium carbonate used multiplied by #bj if #ej cc4 of the sample was used1 or by #aj if #ajj cc4 was used4 ,,mineral ,,acids ,,and ,,sulfates ,,of ,,iron ,,and ,,aluminium4#bd;d#cg ,procedure4--,modify the method for free mineral acids by titrating the water at boiling temperature in the presence of phenolphthalein indicator4 ,the acidity due to free mineral acids and sulfates of iron and aluminium1 expressed in terms of calcium carbonate1 is equal to the number of cubic centimeters of ,n_/#ej sodium carbonate used multiplied by #bj if #ej cc4 of the sample was used1 or by #aj if #ajj cc4 was used4 ,the acidity due to sulfates of iron and aluminium is equal to the acidity due to mineral acids and sulfates minus the acidity due to mineral acids4 ,the acidity due to ferrous and ferric sulfate can be calculated from the determined amount of these salts 7pp4 #dc-dh74 ,the acidity due to aluminium sulfate is equal to the acidity due to total acid sulfates minus that due to iron sulfates4 ,acidity shall be reported in parts per million of calcium carbonate 7,ca,c,o#c74 ,sulfate 7,,so#d7 equals parts per million of calcium carbonate multiplied by #j4if4 ,carbon dioxide 7,,co#b7 equals parts per million of calcium carbonate multiplied by #j4dd4 ,,chloride4#af ,chloride in water and sewage has its origin in common salt1 from mineral deposits in the earth1 from ocean vapors carried inland by the wind1 or from polluting materials like sewage and trade wastes1 which contain the salt used in the household and in manufacturing4 ,comparison of the chloride content of a water with that of other waters in the vicinity known to be unpolluted frequently affords useful information as to its sanitary quality4 ,if1 however1 the chloride normally exceeds #bj parts per million because of chloride-bearing mineral deposits the chloride content of a water has little sanitary significance4 ,reagents4--#a4 ,standard sodium chloride solution4 ,dissolve #af4dh grams of pure fused sodium chloride in #a liter of distilled water4 ,dilute #ajj cc4 of this stock solution to #a liter in order to obtain a standard solution each cubic centimeter of which contains #j4jja gram of chloride4 #b4 ,standard silver nitrate solution4 ,dissolve about #b4dj grams of silver nitrate crystals in #a liter of distilled water4 ,standardize this with the standard salt solution1 and adjust1 correcting for volume 7see p4 #dc71 so that #a cc4 will be exactly equivalent to #j4jjje gram of chloride4 #c4 ,potassium chromate indicator4 ,dissolve #ej grams of neutral potassium chromate in a little distilled water4 ,add enough silver nitrate to produce a slight red precipitate4 ,filter and dilute the filtrate to #a liter with distilled water4 #d4 ,aluminium hydroxide4 ,electrolyze ammonia-free water1 using aluminium electrodes4 ,wash the precipitate until it is free from chloride1 ammonia1 and nitrite4 ,or dissolve #abe grams of potassium or ammonium alum in #a liter of distilled water4 ,precipitate the aluminium by adding cautiously ammonium hydroxide4 ,wash the precipitate in a large jar by successive additions and decantations of distilled water until free from chloride1 nitrite1 and ammonia4 ,procedure4--,add #a cc4 of potassium chromate indicator to #ej cc4 of the sample in a #f-;inch white porcelain evaporating dish or a #aej cc4 ,erlenmeyer flask over a white surface4 ,titrate with the silver nitrate solution under similar conditions of volume1 light1 and temperature as were used in standardizing the silver nitrate until a faint reddish coloration is perceptible4 ,the detection of the end-point is facilitated by comparison of the contents of the porcelain dish with those of another dish containing the same quantity of potassium chromate indicator in #ej cc4 of distilled water4 ,some analysts prefer to make the titration in a dark-room provided with a yellow light4 ,the end-point is very sharp by electric light and also by daylight with photographic yellow glass4 ,the titration may be made in ,nessler tubes#fh;a if the solutions are standardized under similar conditions4 ,if the amount of chloride is very high use #be cc41 or even a smaller quantity1 dilute the volume taken to #ej cc4 with distilled water4 ,if the amount of chloride is very low concentrate #bej cc4 of the sample to #ej cc4 by evaporation4 ,rotate the liquid to make sure that no residue remains undissolved on the walls of the dish1 and1 if necessary1 use a rubber-tipped glass rod to assist in this operation4 ,chloride is determined by some observers by extracting with hot distilled water the residue in the platinum dish in the determination of the residue on evaporation and proceeding as just described4 ,this is permissible if a little sodium carbonate is added before evaporation to prevent loss of chloride through decomposition of magnesium chloride in the residue4 ,if the sample has a color greater than #cj it should be decolorized by shaking it thoroughly with washed aluminium hydroxide 7#c cc4 to #ejj cc4 of the sample7 and allowing the precipitate to settle4 ,make the determination on a portion of the clarified sample1 filtered if necessary4 ,if the sample is acid1 neutralize it with sodium carbonate2 if hydroxide is present1 add dilute sulfuric acid until the cold liquid will just discharge the color of phenolphthalein4 ,if the presence of sulfide and sulfocyanate renders it necessary1 make proper corrections#bd;c#ajj;b or modifications in treatment4 ,make correction for the error due to variations in the volume of the liquid and precipitate by means of the formula#ci ,x #j4jjc,v #j4jb1 in which ,x the correction in cubic centimeters of silver nitrate solution and ,v cubic centimeters of liquid at the end of the titration4 ,if #ej cc4 of the sample is titrated chloride 7,cl7 in parts per million is equal to the number of cubic centimeters of silver nitrate solution multiplied by #aj4 ,the correction to be applied is #j4b cc4 unless unusual accuracy is required4 ,,iron4#id;b#ih ,iron occurs in natural waters in both ferrous and ferric condition1 depending on the source of the sample4 ,in ground waters the iron is usually in an unoxidized and soluble condition1 sometimes combined with carbonic or sulfuric acid1 and also in combination with organic matter4 ,many waters1 especially those that have been exposed to the air1 contain the iron in the form of a colloidal hydroxide4 ,silt-bearing waters often contain much iron in suspension1 usually in an oxidized form4 ,sewages and sewage effluents1 particularly those receiving manufacturing wastes1 contain various forms of iron of different degrees of solubility1 oxidation1 and coagulation4 ,,total ,,iron4#eifc;b ,,colorimetric ,,method4 ,reagents4--#a4 ,standard iron solution4 ,dissolve #j4g gram of crystallized ferrous ammonium sulfate in #ej cc4 of distilled water to which #bj cc4 of dilute sulfuric acid has been added4 ,warm the solution slightly and add potassium permanganate until the iron is completely oxidized4 ,dilute the solution to #a liter4 ,one cc4 of the standard solution equals #j4a mg4 ,fe4 #b4 ,potassium sulfocyanide solution4 ,dissolve #bj grams of the salt in #a liter of distilled water4 #c4 ,dilute hydrochloric acid4 ,one volume of acid 7,sp4 gr4 #a4b7 and one volume of distilled water4 ,this shall be free from nitric acid4 #d4 ,n_/#e potassium permanganate4 ,dissolve #f4cj grams of the salt in distilled water and dilute to #a liter4 #e4 ,hydrochloric acid4 ,concentrated1 free from iron4 #f4 ,nitric acid4 ,concentrated1 free from iron4 #g4 ,nitric acid4 #e,n1 free from iron4 ,first procedure4--,evaporate #ajj cc4 of the water to dryness1 or use the residue left after the determination of residue on evaporation 7p4 #bi74 ,ignite the residue at a low red heat taking care not to heat it hot enough to make the iron difficultly soluble4 ,cool the dish and add #e cc4 of concentrated hydrochloric acid4 ,moisten the inner surface of the dish4 ,warm the solution for two or three minutes1 and again moisten the inner surface of the dish by permitting the hot acid to flow over it4 ,wash the hot solution from the dish into a #ej cc4 ,nessler tube1 filtering if necessary through paper that has been washed with hot water4 ,dilute to #ej cc41 and add #c drops of potassium permanganate solution4 ,add #e cc4 of potassium sulfocyanide solution1 mix1 and compare with standards4 ,if it is not convenient to use the residue on evaporation and if the sample is relatively free from organic matter1 boil #ej cc4 of the sample with #e cc4 of #e,n nitric acid for five minutes4 ,add a few drops of permanganate and #e cc4 of potassium sulfocyanide and compare with standards1 using nitric acid in place of hydrochloric acid in the standards4 ,this method is excellent for ground waters4 ,the permanganate and acid liberate chlorine in water high in chloride1 and produce a permanent yellow color which interferes with the determination1 unless the sample is first diluted to #ej cc4 ,an excess of permanganate1 reacting with hydrochloric acid1 causes similar trouble4 ,the amounts of hydrochloric acid1 #e cc41 and of sulfocyanide1 #e cc41 should be approximately measured because more acid lightens the color whereas more sulfocyanide deepens it4 ,this is especially important if permanent standards are used4 ,second procedure4--,for surface waters containing small amounts of organic matter1 the method of ,klut#ei is recommended4 ,samples containing small amounts of iron should be concentrated1 if possible1 until at least #j4e mg4 of iron is present in the volume tested4 ,boil the sample in a beaker with #b to #c cc4 of concentrated nitric acid free from iron1 adding permanganate if necessary to destroy the organic matter4 ,to the hot liquid add ammonia in slight excess and warm until the smell of ammonia is hardly discernible4 ,filter and wash with water at #gj to #hj ,c4 containing a little ammonia4 ,dissolve the iron in the beaker and on the filter paper in #e cc4 of concentrated hydrochloric acid1 and wash with hot water until the iron is all dissolved1 collecting the filtrate in a #ej cc4 ,nessler tube4 ,dilute to #ej cc4 ,add potassium sulfocyanide and determine the iron by comparison with standards4 ,,comparison ,,with ,,iron ,,standards4 ,first procedure4--,prepare standards containing amounts of standard iron solution ranging from #j4je to #d cc4 according to the quantity of iron in the sample4 ,dilute these amounts with water to about #dj cc4 ,add #e cc4 of dilute hydrochloric acid and #c drops of potassium permanganate to each tube and dilute to #ej cc4 ,add #e cc4 of the potassium sulfocyanide to each of the standard solutions at the same time that it is added to the samples of water under examination1 and compare immediately after mixing4 ,if #ajj cc4 of the sample is used the iron in parts per million is equal to the number of cubic centimeters of the standard iron solution in the standard that the sample matches4 ,second procedure4--,for a small number of determinations it is more convenient to run the standard iron solution into a ,nessler tube containing the acid1 distilled water1 and potassium sulfocyanide until the color matches that of the sample tested4 ,when determining iron in three or four samples the colors may be matched in the order of their intensity and the volumes of standard iron solution required for each tube may be read from the burette4 ,,comparison ,,with ,,permanent ,,standards4 ,reagents4--#a4 ,platinum solution4 ,dissolve #b grams of potassium platinic chloride 7,pt,cl#d4b,k,cl7 in distilled water1 add #ajj cc4 of concentrated hydrochloric acid1 and dilute to #a liter with distilled water4 #b4 ,cobalt solution4 ,dissolve #bd grams of dry cobaltous chloride crystals 7,co,cl#b4f;,h#b,o7 in a small amount of distilled water1 add #ajj cc4 of strong hydrochloric acid1 and dilute to #a liter with distilled water4 ,procedure4--,prepare a series of permanent standards by diluting to #ej cc4 with distilled water the amounts of platinum and cobalt solutions1 in #ej cc4 ,nessler tubes1 indicated in ,table #i4 ,compare the sample with these standards1 and calculate the parts per million of iron4 ,table #i4--,,preparation ,,of ,,permanent ,,standards ,,for ,,the ,,determination ,,of ,,iron4 ,value in standard iron ,platinum solution4 ,cobalt solution4 solution4 cc4 cc4 cc4 #j4j #j #j4j 4#a #b #a4j 4#c #f #c4j 4#e #aj #e4j 4#g #ad #g4e #a4j #bj #aa4j #a4e #bh #ag4j #b4j #ce #bd4j #b4e #ci #cb4j #c4j #ci #dc4j #c4e #dj #ee4j ,,volumetric ,,method4#bd;f ,some samples of sewage and water mixed with trade wastes and mine drainage contain so much iron that it is preferable to use the volumetric method described on page #eg for the determination of both total and dissolved iron1 rather than to work with quantities small enough to permit application of the colorimetric methods just described4 ,if iron is present in large quantities in suspension1 as in some sewages and septic tank effluents1 it may be filtered off and the residue washed1 ignited1 and fused with potassium and sodium carbonate4 ,the fusion is then extracted with hydrochloric acid and the iron determined as on page #eg4 ,samples containing much organic matter should be evaporated to dryness with #j4e cc4 of concentrated sulfuric acid and the residue then ignited before estimation of iron4 ,,dissolved ,,iron4 ,determine1 by the method described for total iron1 the iron in the sample after filtration4 ,iron may precipitate from some samples during filtration4 ,,suspended ,,iron4 ,the suspended iron is the difference between total iron in the unfiltered sample and dissolved iron in the filtered sample4 ,,ferrous ,,iron4#bd;e ,determine the total ferrous iron in an unfiltered sample and the dissolved ferrous iron in a filtered sample4 ,reagents4--#a4 ,standard iron solution4 ,dissolve #j4g gram of crystallized ferrous ammonium sulfate in a large volume of freshly boiled distilled water to which #aj cc4 of dilute sulfuric acid has been added and dilute to #a liter4 ,this solution should be freshly prepared when needed4 ,one cc4 of this standard solution contains #j4a mg4 of ,fe4 #b4 ,potassium ferricyanide solution4 ,dissolve #e grams of the salt in #a liter of distilled water4 ,use a freshly prepared solution4 #c4 ,dilute sulfuric acid4 ,dilute #a part of sulfuric acid1 specific gravity #a4hd1 with #e parts of distilled water4 ,procedure4--,add #aj cc4 of dilute sulfuric acid to #ej cc4 of the sample1 remove the suspended matter by filtration if necessary1 and add #ae cc4 of potassium ferricyanide solution4 ,dilute the solution to #ajj cc4 with distilled water4 ,compare the color developed in the sample with that in standards made at the same time from the ferrous iron solution4 ,place in #ajj cc4 ,nessler tubes1 in the following order1 #ge cc4 of distilled water1 #aj cc4 of dilute sulfuric acid1 and #ae cc4 of potassium ferricyanide solution1 and mix well the contents of each tube4 ,prepare as many tubes in this way as are needed4 ,add various quantities of standard ferrous iron solution to several tubes1 mix well1 and compare the resulting colors with the samples immediately4 ,,ferric ,,iron4 ,the amount of ferric iron in solution and suspension is equal to the difference between the total iron and the ferrous iron obtained by the methods described4 ,,manganese4 ,if the sample contains less than #aj parts per million of manganese1 use a colorimetric method in which the manganous salt is oxidized to permanganate and the color produced thereby is compared with that of a standard solution similarly treated4 ,the persulfate method and the bismuthate method are suitable4 ,if the sample contains more than #aj parts per million of manganese it is sometimes preferable to use a volumetric or gravimetric method4 ,,persulfate ,,method4 ,reagents4--#a4 ,nitric acid4 ,dilute concentrated nitric acid with an equal volume of distilled water4 ,free the diluted acid from brown oxides of nitrogen by aeration4 #b4 ,silver nitrate4 ,dissolve #bj grams of silver nitrate in #a liter of distilled water4 #c4 ,standard manganous sulfate4 ,dissolve #j4bhh gram of purest potassium permanganate in about #ajj cc4 of distilled water4 ,acidify the solution with sulfuric acid and heat to boiling4 ,add slowly a sufficient quantity of dilute solution of oxalic acid to discharge the color4 ,cool and dilute to #a liter4 ,one cc4 of this solution contains #j4a mg4 of manganese4 #d4 ,ammonium persulfate4 ,crystals1 free from chloride4 ,procedure4--,use an amount of the sample that contains not more than #j4b mg4 of manganese4 ,add #b cc4 of nitric acid and boil down to about #ej cc4 ,precipitate the chloride with silver nitrate solution1 adding at least #a cc4 in excess4 ,shake and heat to coagulate the precipitate1 and filter4 ,a sample that contains much chloride should be evaporated with a few drops of sulfuric acid until white fumes appear and then diluted before the nitric acid and silver nitrate are added as directed above4 ,if the sample is highly colored by organic matter it should be evaporated with sulfuric acid1 and the residue ignited and dissolved in dilute nitric acid4 ,add about #j4e gram of ammonium persulfate crystals and warm the solution until the maximum permanganate color is developed4 ,this usually takes about ten minutes4 ,at the same time prepare standards by diluting portions of #j4b1 #j4d1 #j4f cc41 etc4 of the standard manganous sulfate solution to about #ej cc4 and treating them exactly as the sample was treated4 ,transfer the sample and the standards to #ej cc4 ,nessler tubes1 and compare the colors immediately4 ,manganese in parts per million is equal to the number of cubic centimeters of standard manganous sulfate solution in the tube that the sample matches multiplied by #ajj1 divided by the number of cubic centimeters of the sample used4 ,,bismuthate ,,method4#b;a#aac ,reagents4--#a4 ,nitric acid4 ,dilute #a part of concentrated nitric acid with #d parts of distilled water4 ,free the dilute acid from brown oxides of nitrogen by aeration4 #b4 ,sulfuric acid4 ,dilute #a part of concentrated sulfuric acid with #c parts of distilled water4 #c4 ,dilute sulfuric acid4 ,dilute #be cc4 of concentrated acid to #a liter with distilled water4 ,add enough permanganate solution to color faintly the dilute acid4 #d4 ,standard manganous sulfate4 ,the standard solution of manganous sulfate prepared as described under persulfate method 7p4 #dh7 should be used and the standards should be prepared by following the same procedure as is used for the sample4 ,this solution is more permanent than a solution of potassium permanganate1 which may1 however1 be used4 ,to prepare it dissolve #j4bhh gram of potassium permanganate in distilled water and dilute the solution to #a liter4 #e4 ,sodium bismuthate4 ,purest dry salt4 ,procedure4--,use an amount of the sample that contains not more than #j4b mg4 of manganese4 ,add #j4e cc4 of sulfuric acid and evaporate to dryness4 ,heat until the sulfuric acid is volatilized and ignite the residue4 ,dissolve in #dj cc4 of nitric acid1 add about #j4e gram of sodium bismuthate1 and heat until the permanganate color disappears4 ,add a few drops of a solution of ammonium or sodium bisulfate to clear the solution and again boil to expel oxides of nitrogen4 ,remove from the source of heat1 cool to #bj ,c41 again add #j4e gram of sodium bismuthate1 and stir4 ,when the maximum permanganate color has developed1 filter through an alundum or ,gooch crucible containing an asbestos mat ignited and washed with potassium permanganate4 ,wash the precipitate with dilute sulfuric acid until the washings are colorless4 ,transfer the filtrate to a #ej cc4 ,nessler tube and compare the color of it with that of standards prepared from the potassium permanganate solution4 ,to prepare the standards1 dilute portions of #j4b1 #j4d1 #j4f cc41 etc4 of the permanganate solution to #ej cc4 with dilute sulfuric acid4 ,the content of manganese is calculated as described under persulfate method 7p4 #di74 ,,lead1 ,,zinc1 ,,copper1 ,,and ,,tin4#gfj ,determinations of lead1 zinc1 copper1 and tin are important in certain mining regions and in places where the water has a solvent action on pipes and other containers4 ,the use of certain 8germicides0 also makes it necessary to test for some of these metals4 ,lead1 zinc1 and copper may be determined colorimetrically or electrolytically4 ,the colorimetric methods are not so accurate as a combination of both1 and are chiefly of value as qualitative tests4 ,it is possible to make a rough estimation of the amount of lead in clear waters by acidifying with acetic acid1 saturating with hydrogen sulfide1 and comparing the color produced with that produced by standard lead solutions in ,nessler tubes1 treated in similar manner4 ,this method1 however1 is not applicable if the water is colored or contains iron4 ,reagents4--#a4 ,standard lead solution4 ,dissolve #a4fj grams of lead nitrate 7,pb7,,no#c7b7 in #a liter of distilled water4 ,one cc4 of this solution contains #a mg4 of lead 7,pb74 ,as a check it is desirable to determine lead as sulfate in a measured portion of this solution4 #b4 ,standard copper solution4 ,dissolve about #j4h gram of copper sulfate crystals 7,cu,s,o#d4e;,h#b,o7 in water and1 after the addition of #a cc4 of concentrated sulfuric acid1 dilute the solution to #a liter4 ,determine the copper in #ajj cc4 of this solution in the usual way by electrolytic deposition4 ,dilute the solution so that #a cc4 contains #j4b milligram copper 7,cu74 ,this solution is permanent4 #c4 ,ammonium chloride4 ,twenty-five per cent solution4 #d4 ,ammonium acetate4 ,fifty per cent solution4 #e4 ,ammonium hydroxide4 7,sp4 gr4 #j4if47 #f4 ,hydrogen sulfide4 ,saturated solution4 #g4 ,potassium sulfide4 ,an alkaline solution of potassium sulfide made by mixing equal volumes of #aj per cent potassium hydroxide and a saturated aqueous solution of hydrogen sulfide4 #h4 ,potassium oxalate4 ,crystals4 #i4 ,potassium sulfate4 ,crystals4 #aj4 ,alcohol4 ,ninety-five per cent4 #aa4 ,alcohol4 ,fifty per cent4 #ab4 ,acetic acid4 ,fifty per cent4 #ac4 ,nitric acid4 ,concentrated acid 7,sp4 gr4 #a4db74 #ad4 ,nitric acid4 ,dilute #a part of the concentrated acid to #aj parts with distilled water4 #ae4 ,hydrochloric acid4 7,sp4 gr4 #a4bj47 #af4 ,sulfuric acid4 ,concentrated acid 7,sp4 gr4 #a4hd74 #ag4 ,sulfuric acid4 ,dilute the concentrated acid with an equal volume of distilled water4 #ah4 ,urea4 ,crystals4 ,,lead4 ,concentrate 7#a7;,d rapidly by boiling in a #g-;inch porcelain dish over a free flame #c or #d liters of the sample to be tested1 or more if very small amounts of the metals are present1 to a volume of about #cj cc4 ,add #aj or #ae cc4 of ammonium chloride solution to assist in the separation of the sulfides1 then add a few drops of concentrated ammonium hydroxide1 and saturate with hydrogen sulfide4 ,allow to stand some time1 preferably over night1 add a little more ammonium hydroxide and hydrogen sulfide1 boil the contents of the dish a few minutes1 and filter4 ,the precipitate 7#b7 may consist of lead1 zinc1 copper1 and iron sulfides and the suspended organic matter4 ,the soluble coloring matter is in the filtrate 7#c74 ,wash the precipitate a few times with hot water1 place the precipitate and the filter paper in the original dish and boil with dilute nitric acid1 rubbing down the sides of the dish1 if necessary1 to detach any adhering sulfide precipitate4 ,after again filtering and washing several times with hot water1 evaporate the filtrate and washings in the original dish to a bulk of #aj to #ae cc41 cool1 add #e cc4 of concentrated sulfuric acid1 and heat until copious fumes of sulfuric acid are evolved4 ,footnote ,d3 ,the numbers in parentheses refer to tables #aj-ab1 pages #ee-ef4 ,if lead is present dilute the contents of the dish slightly with water1 and treat them with #aej cc4 of #ej per cent alcohol1 in which the lead sulfate is insoluble4 ,allow to stand some time1 preferably over night1 filter off the lead sulfate1 and wash it with #ej per cent alcohol4 ,save the filtrate for the determination of zinc4 ,dissolve the precipitate of lead sulfate by boiling the filter containing it in ammonium acetate solution in a porcelain dish4 7#d74 ,filter into a #ej cc4 ,nessler tube and wash the filter with boiling water containing a little ammonium acetate4 ,divide this filtrate in halves and treat one-half with saturated hydrogen sulfide water in order to get an approximation of the amount of lead present4 ,to the other half1 or an aliquot portion1 if a large amount of lead is present1 add a few drops of acetic acid1 then an excess of saturated hydrogen sulfide solution1 and compare the color with that of standards made by treating known amounts of the standard lead solution with a little acetic acid1 ammonium acetate1 and hydrogen sulfide4 ,,zinc4 ,if zinc is present and copper is absent concentrate the filtrate from the lead sulfate to expel the alcohol1 and remove the iron by adding an excess of ammonium hydroxide4 ,filter1 wash1 and acidify the filtrate with sulfuric acid4 ,concentrate the filtrate to about #aej cc4 and transfer to a weighed platinum dish4 ,add #b grams of potassium oxalate and #a4e grams of potassium sulfate4 ,deposit the zinc electrolytically by means of a current of about #j4c ampere for three hours4 ,after deposition is complete and while the current is on1 siphon off the solution and at the same time run into the dish a stream of distilled water in order to expel the free sulfuric acid1 which might dissolve some of the zinc if the circuit were broken4 ,after the acid has been removed break the circuit1 wash the dish with water1 then with #ie per cent alcohol1 dry at #gj ,c41 cool1 and weigh it4 ,the difference between this weight 7#aj7 and the weight of the platinum dish equals the amount of metallic zinc4 ,some difficulty has been experienced in this determination in obtaining pure reagents4 ,it is therefore advisable to make blank determinations with each new lot of reagents and to correct the results if necessary4 ,if copper also is present 7#e7 concentrate the filtrate from the lead sulfate until the alcohol is expelled1 and add an excess of ammonium hydroxide4 7#f7 ,remove any iron precipitate by filtration4 ,neutralize the filtrate 7#g7 with sulfuric acid1 and add #b cc4 of concentrated sulfuric acid and #a gram of urea4 ,electrolyze the solution and determine copper colorimetrically as described in the procedure for copper 7p4 #ed74 ,after the copper has been deposited add ammonium hydroxide to the solution containing the zinc until nearly all the sulfuric acid has been neutralized1 concentrate to slightly less than the capacity of the platinum dish1 add #a4e grams of potassium sulfate and #b grams of potassium oxalate1 and electrolyze for zinc4 ,as this solution is usually saturated with ammonium salts due to neutralizing the large quantity of sulfuric acid1 it is frequently impossible to get the zinc deposited firmly on the dish before the salts interfere by crystallization4 ,to avoid this difficulty1 dilute half the solution and electrolyze it for zinc2 or1 if the amount of zinc is very small1 precipitate the zinc as sulfide in acetic acid solution1 wash1 ignite to oxide1 and weigh the precipitate4 ,this difficulty will not be encountered if copper is absent as there will then be no excess of ammonium salts4 ,if lead and copper are known to be absent and zinc alone is to be determined 7#ac71 after treating with sulfuric acid for separation of lead1 slightly dilute the contents of the dish4 ,add an excess of ammonium hydroxide to precipitate iron and filter4 ,make the filtrate slightly acid with sulfuric acid1 concentrate to about #aej cc41 transfer to a weighed platinum dish1 add potassium oxalate and sulfate1 and electrolyze the solution as described for deposition of zinc4 ,,copper4#gg ,use #a liter of a sample containing #j4a to #a4j part per million of copper1 and proportionate amounts for other concentrations4 ,evaporate to about #ge cc41 and wash into a #ajj cc4 platinum dish4 ,add #b cc4 of dilute sulfuric acid for clear and soft waters2 add more acid to very alkaline waters to offset the alkalinity2 add #e cc4 of acid to waters carrying much organic matter or clay to insure the formation of a soluble copper salt4 ,then place the dish as the anode in a direct current circuit1 suspend a spiral wire cathode in the solution so that it is parallel to and about half an inch from the bottom of the dish1 and close the circuit4 ,electrolyze for about four hours with occasional stirring1 or over night1 if convenient4 ,the current may be supplied by two gravity cells in series1 yielding a current through the solution of about #j4jb ampere4 ,lift out the cathode without previously opening the circuit1 and immerse the spiral in a small amount of dilute nitric acid previously heated to boiling4 ,wash off the wire and evaporate the nitric acid solution to dryness on the water bath4 ,if the presence of silver is suspected add a few drops of hydrochloric acid before evaporation4 ,dissolve the residue in water and wash it into a #ej cc4 ,nessler tube4 ,dilute to #ej cc4 and add #aj cc4 of the potassium sulfide solution4 ,the color of the copper sulfide develops at once and is fairly permanent1 lasting at least several hours4 ,add #aj cc4 of the potassium sulfide solution to a similar tube containing #ej cc4 of distilled water1 and then add to it standard copper solution in #j4b cc4 portions until the colors of the two tubes match4 ,if #a liter of the sample is used copper in parts per million is equal to the number of cubic centimeters of standard copper solution required to match the color of the sample multiplied by #j4b4 ,,tin4 ,small quantities of tin are occasionally found in waters that have passed through tin or tin-lined pipes4 ,this metal1 if present1 is precipitated with the iron by ammonia in the lead1 zinc1 and copper separations4 ,in the method for copper alone1 it is removed in the same way and may be further avoided by dissolving the sulfides in concentrated nitric acid4 ,any tin present will then separate as an insoluble compound1 which may be ignited and weighed as the oxide 7,sn,o#b74 ,the following schematic tables illustrate the procedures given4 ,table #aj4--,,scheme ,,for ,,the ,,separation ,,of ,,lead1 ,,zinc1 ,,and ,,copper4 #a4 ,concentrate sample4 ,add #aj cc4 ,,nh#d;,cl1 a few drops ,,nh#d,,oh and saturate with ,h#b,s4 ,allow to stand1 add more ,,nh#d,,oh and ,h#b,s4 ,boil1 filter1 and wash4 #b4 ,dissolve the precipitate in dilute ,,hno#c4 ,filter #c4 ,reject the and wash4 ,evaporate to #aj or #ae cc4 ,cool4 ,add #e cc4 filtrate which concentrated ,h#b,,so#d1 and heat until white fumes arecontains the given off4 ,dilute slightly and treat with #aej cc4 of #ej coloring per cent alcohol4 ,allow to stand2 filter1 and wash with matter4 #ej per cent alcohol4 #d4 ,the precipitate #e4 ,the filtrate contains the contains the ,pb4 ,dissolve ,zn and ,cu4 ,concentrate to in ,,nh#d;,c#b;,h#c,o#b expel alcohol4 ,add excess of solution4 ,filter into a #ej,,nh#d,,oh1 filter and wash cc4 ,nessler tube and wash precipitate4 with water containing ,,nh#d;,c#b;,h#c,o#b4 #f4 ,reject the #g4 ,the filtrate contains the ,divide filtrate in halves4precipitate ,zn and ,cu4 ,neutralize with ,saturate one-half with which contains,h#b,,so#d4 ,add #aj cc4 ,h#b,s4 ,determine the ,pb the ,fe4 concentrated ,h#b,,so#d and in the other half by #a g4 urea4 ,electrolyze for adding ,,hc#b;,h#c,o#b two hours with a current of and ,h#b,s and comparing #j4e ampere4 ,break circuit1 with standards containing empty dish and wash4 known amounts of ,pb4 #h4 ,the deposit is ,cu4 #i4 ,the solution contains the ,zn4 ,nearly ,immerse the cathode in a neutralize with ,,nh#d,,oh4 ,concentrate to small amount of hot1 less than the capacity of the dish4 ,add #b g4 dilute ,,hno#c2 wash off ,k#b;,c#b,o#d and #a4e g4 ,k#b,,so#d4 and evaporate to dryness4 ,electrolyze for #c hours with a current of ,take up in water and wash #j4c ampere4 ,siphon off solution1 break into a ,nessler tube4 ,make circuit1 wash with water1 then alcohol1 dry up to mark1 and add #aj cc4at #gj ,c41 cool and weigh4 of potassium sulfide solution4 ,compare with #aj4 ,the weighed residue is metallic ,zn4 standard4 ,if large amount is present1 dry and weigh as ,cu4 ,table #aa4--,,scheme ,,for ,,determination ,,of ,,copper ,,only4 #aa4 ,concentrate sample to #ge cc4 ,add #b cc4 conc4 ,h#b,,so#d for clear1 soft waters and #e cc4 for alkaline or turbid waters4 ,electrolyze following procedure in #g and #h4 ,table #ab4--,,scheme ,,for ,,determination ,,of ,,zinc ,,only4 #ac4 ,follow scheme for all three metals as given in ,table #aj through section #e4 ,nearly neutralize the filtrate with ,h#b,,so#d1 concentrate to less than the capacity of the dish and electrolyze as directed in section #i4 ,,mineral ,,analysis4 ,,residue ,,on ,,evaporation4 ,see description of method 7p4 #bi74 ,the residue should be dried one hour at #ahj ,c4 ,turbid waters should be filtered1 and the composition of the suspended matter should be determined separately or the amount of it reported as suspended matter4 ,,alkalinity ,,and ,,acidity4 ,see description of method 7pp4 #ce-da74 ,,chloride4 ,see description of method 7pp4 #da-dc74 ,,nitrate ,,nitrogen4 ,see description of method 7pp4 #bc-be74 ,,separation ,,of ,,silica1 ,,iron1 ,,aluminium1 ,,calcium1 ,,and ,,magnesium4#ajdh ,,silica4 ,evaporate in platinum #ajj to #a1jjj cc4 of the sample or sufficient if possible to form a residue weighing #j4d to #j4f gram1 and preferably containing #j4a to #j4b gram of calcium4 ,when the residue is nearly dry add #a cc4 of hydrochloric acid 7#a to #a7 and1 after moistening the sides of the dish1 evaporate to dryness4 ,dry at #ahj ,c4 and if much organic matter is present char it in a radiator4 ,moisten the residue with dilute hydrochloric acid and expel the excess of acid by heating on the water bath4 ,add a few drops of hydrochloric acid1 dissolve in hot water1 and filter4 ,wash the residue with hot water4 ,evaporate the filtrate to dryness1 repeat the filtration1 and combine the two residues4 ,if great accuracy is not required the second evaporation with hydrochloric acid may be omitted4 ,ignite and weigh the insoluble residue4 ,add #b drops of concentrated sulfuric acid and a little hydrofluoric acid1 volatilize the acids1 ignite1 and weigh again4 ,report the loss in weight as silica 7,si,o#b74 ,a weight of non-volatile matter exceeding #j4e mg4 should be analyzed4 ,,iron ,,and ,,aluminium4 ,heat to boiling the filtrate from the insoluble residue1 oxidize with concentrated nitric acid or bromine1 and concentrate to about #be cc4 ,add ammonium hydroxide in slight excess1 boil one minute1 and filter4 ,dissolve the precipitate on the filter in a small amount of hot dilute hydrochloric acid4 ,reprecipitate with ammonium hydroxide1 filter1 and wash4 ,unless very accurate results are necessary this solution and reprecipitation may be omitted4 ,unite the two filtrates for determination of calcium4 ,ignite and weigh the precipitate4 ,it will comprise oxides of iron and aluminium and phosphate4 ,if much phosphate is present it should be determined in a separate sample and a correction for the amount applied2 otherwise it may be neglected4 ,determine the iron in the ignited precipitate by fusion with sodium or potassium pyrosulfate1 reduction with zinc1 and titration with potassium permanganate4 ,aluminium 7,al7 is calculated as follows3 ,al #j4ec7;,fe#b,o#c ,al#b,o#c7 #a4dc ,fe ,,calcium4 ,concentrate the filtrate from the separation of iron and aluminium to about #ajj cc41 and add an excess of concentrated solution of ammonium oxalate1 little by little1 to the hot ammoniacal solution4 ,keep the solution warm and stir at intervals till the precipitate settles readily and leaves a clear supernatant liquid4 ,filter1 dissolve the precipitate in a little hot dilute hydrochloric acid1 and reprecipitate with ammonium hydroxide and ammonium oxalate4 ,if great accuracy is not required this solution and reprecipitation may be omitted1 and the first precipitate may be washed clean with hot water#fd;a4 ,save the filtrate for determination of magnesium4 ,ignite the precipitate and weigh it as calcium oxide1 #ga4e per cent of which is the equivalent of calcium 7,ca72 or dissolve the precipitate in hot #b per cent sulfuric acid and titrate with a standard solution of potassium permanganate4 ,,magnesium4 ,acidify with hydrochloric acid the filtrate from the separation of calcium and concentrate it to about #ajj cc4 ,add #bj cc4 of a saturated solution of microcosmic salt1 cool1 and make slightly but distinctly alkaline by adding ammonium hydroxide1 drop by drop4 ,allow the solution to stand four hours1 then filter and wash with #c per cent ammonium hydroxide4 ,dissolve the precipitate1 especially in the presence of large amounts of sodium or potassium1 in a slight excess of dilute hydrochloric acid and reprecipitate the magnesium with ammonium hydroxide and a few drops of microcosmic salt solution4 ,if great accuracy is not required this solution and reprecipitation may be omitted4 ,ignite the precipitate and weigh it as magnesium pyrophosphate 7,mg#b,p#b,o#g71 #ba4i per cent of which is the equivalent of magnesium 7,mg474 ,if manganese is present#fd;a it is precipitated with the magnesium and a correction for it should be applied after having determined manganese in a separate sample4 ,the weight of manganese pyrophosphate 7,mn#b,p#b,o#g7 is #b4eh times the weight of manganese4 ,,separation ,,of ,,sulfate1 ,,sodium1 ,,and ,,potassium4 ,,sulfate4 ,evaporate to dryness #ajj to #a1jjj cc4 of the sample1 or sufficient to obtain a residue weighing #j4d to #j4f gram and containing preferably #j4je to #j4b gram of sodium4 ,acidify the residue with hydrochloric acid and remove the silica1 iron1 and aluminium 7pp4 #ef-eg74 ,make acid and add a hot solution of barium chloride in slight excess to the hot filtrate1 and warm it1 stirring at intervals for one-half hour1 until the precipitate settles readily and leaves a clear supernatant liquid4 ,dry1 ignite1 and weigh the precipitate of barium sulfate1 #da4a per cent of which is equal to the content of sulfate 7,,so#d74 ,,sodium1 ,,potassium1 ,,and ,,lithium4 ,evaporate to dryness the filtrate from the precipitation of barium sulfate4 ,add a few cubic centimeters of hot water and then a saturated solution of barium hydroxide until a slight film collects on the top of the solution4 ,filter and wash the precipitate with hot water4 ,add to the filtrate an excess of ammonium hydroxide and ammonium carbonate solution4 ,filter1 evaporate the filtrate to dryness1 dry1 and ignite at low red heat to expel ammonium salts4 ,repeat the operations including the addition of barium hydroxide until no precipitate is obtained by barium hydroxide or by ammonium hydroxide and ammonium carbonate4 ,evaporate the final filtrate to dryness in a weighed platinum dish1 dry1 cool1 and weigh the residue4 ,dissolve the residue in a few cubic centimeters of water1 filter1 wash the filter paper twice with hot water1 then ignite the filter paper in the platinum dish4 ,cool and weigh the residue4 ,subtract this weight from the first weight including the residue4 ,the difference is the weight of the chlorides of sodium and potassium and lithium4 ,if it is not desired to separate sodium and potassium the weight of sodium and potassium as sodium may be calculated from this difference by multiplying it by #j4cid4 ,,potassium4 ,first procedure4--,add to the solution of the chlorides of sodium and potassium a few drops of dilute hydrochloric acid 7#a to #c7 and #a cc4 of #aj per cent platinic chloride 7,pt,cl#d7 for each #cj mg4 of the combined chlorides4 ,evaporate to a thick syrup on the water bath1 then remove dish and allow it to come to dryness at laboratory temperature4 ,treat the residue cold with #hj per cent alcohol and filter4 ,wash the precipitate with #hj per cent alcohol until the filtrate is no longer colored4 ,dry the precipitate and dissolve it in hot water4 ,evaporate the solution to dryness in a platinum dish and weigh it as potassium platinic chloride 7,k#b,pt,cl#f74 ,the weight of potassium 7,k7 is #af4a per cent of this weight and the equivalent of potassium chloride 7,k,cl7 is #cj4g per cent of this weight4 ,subtract the equivalent weight of potassium chloride from the weight of the combined chlorides4 ,the weight of the sodium is #ci4d per cent of the difference4 ,second procedure4#hfajc;a--,add to the hot solution of the combined chlorides #bj per cent perchloric acid 7,h,cl,o#d7 slightly in excess of the amount required to combine with the bases4 ,one cubic centimeter of #bj per cent perchloric acid is equivalent to #ij mg4 of potassium4 ,evaporate the solution to dryness1 dissolve the residue in #aj cc4 of hot water and a small amount of perchloric acid1 and again evaporate to dryness4 ,repeat the addition of water1 perchloric acid1 and evaporation until white fumes appear on evaporating to dryness4 ,add to the residue #be cc4 of #if per cent alcohol containing #j4b per cent of perchloric acid 7#a cc4 of #bj per cent perchloric acid in #ajj cc4 of #ih per cent alcohol74 ,break up the residue with a stirring rod4 ,decant the supernatant liquid through a weighed ,gooch crucible that has been washed with #j4b per cent perchloric acid in alcohol4 ,if the precipitate is unusually large dissolve it in hot water and repeat the evaporation with perchloric acid4 ,wash the precipitate once by decantation with the #j4b per cent perchloric acid in alcohol1 transfer the precipitate to the crucible1 and wash it several times with a #j4b per cent perchloric acid in alcohol4 ,dry the crucible at #abj-acj ,c4 for one hour1 cool1 and weigh it4 ,the increase in weight is potassium perchlorate 7,k,cl,o#d74 ,the equivalent weight of potassium is #bh4b per cent and the equivalent weight of potassium chloride is #ec4h per cent of the potassium perchlorate4 ,calculate the content of sodium by difference4 ,,lithium4#cd ,use a large quantity of the sample4 ,obtain the combined chlorides of sodium1 potassium1 and lithium 7see pp4 #eh-ei74 ,transfer the combined chlorides to a small ,erlenmeyer flask 7#ej or #ajj cc4 capacity7 and evaporate the solution nearly1 but not quite1 to dryness4 ,add about #cj cc4 of redistilled amyl alcohol4 ,connect the flask1 the stopper of which carries a thermometer1 with a condenser,e and boil until the temperature rises approximately to the boiling point of amyl alcohol 7#acj ,c471 showing that all the water has been driven off4 ,cool slightly and add a drop of hydrochloric acid to convert small amounts of lithium hydroxide to lithium chloride4 ,connect with the condenser and continue the boiling to drive off again all water and until the temperature reaches the boiling point of amyl alcohol4 ,the content of the flask at this time is usually #ae to #bj cc4 ,filter through a small paper or a ,gooch crucible into a graduated cylinder and note exact quantity of filtrate1 which determines the subsequent correction4 ,wash the precipitate with small quantities of dehydrated amyl alcohol4 ,evaporate the filtrate and washings in a platinum dish to dryness on the steam bath1 dissolve the residue in water1 and add a few drops of sulfuric acid4 ,evaporate on a steam bath and expel the excess of sulfuric acid by gentle heat over a flame4 ,repeat until carbonaceous matter is completely burned off4 ,cool and weigh the dish and contents4 ,dissolve in a small quantity of hot water1 filter through a small filter1 wash1 and return filter to dish1 ignite1 and weigh4 ,the difference between the original weight of dish and contents and the weight of the dish and small amount of residue equals the weight of impure lithium sulfate4 ,the purity of the lithium sulfate should be tested by adding small amounts of ammonium phosphate and ammonium hydroxide1 which will precipitate any magnesium present with the lithium sulfate4 ,any precipitate appearing after standing over night should be collected on a small filter and weighed as magnesium pyrophosphate1 calculated to sulfate1 and subtracted from the weight of impure lithium sulfate4 ,from this weight subtract #j4jjaac gram for every #aj cc4 of amyl alcohol filtrate exclusive of the amyl alcohol used in washing residue because of the slight solubility of solid mixed chlorides in amyl alcohol4 ,calculate lithium from the corrected weight of lithium sulfate4 ,dissolve the mixed chlorides from flask and filter with hot water1 evaporate to dryness1 ignite gently to remove amyl alcohol1 filter and thoroughly wash2 concentrate the filtrates and washings to #be to #ej cc4 ,footnote ,e3 ,the amyl alcohol may be boiled off without the use of a condenser1 but the vapors are very disagreeable4 ,to the weight of potassium chloride add #j4jjjea gram for every #aj cc4 of amyl alcohol used in the extraction of the lithium chloride1 which corrects for the solubility of the potassium chloride in amyl alcohol4 ,calculate to potassium4 ,the weight of sodium chloride is found by subtracting the combined weights of lithium chloride and potassium chloride 7corrected7 from the total weight of the three chlorides4 ,calculate sodium chloride to sodium4 ,,bromine1 ,,iodine1 ,,arsenic1 ,,and ,,boric ,,acid4 ,evaporate to dryness a large quantity of the sample to which a small amount of sodium carbonate has been added4 ,boil the residue with distilled water1 transfer it to a filter1 and thoroughly wash it with hot water4 ,dilute the alkaline filtrate to a definite volume1 and determine bromine and iodine1 arsenic1 and boric acid in aliquot portions of it4 ,,bromine ,,and ,,iodine4#aj ,reagents4--#a4 ,sulfuric acid4 #a to #e4 #b4 ,potassium nitrite or sodium nitrite4 ,two per cent solution4 #c4 ,carbon bisulfide4 ,freshly purified by distillation4 #d4 ,iodine standards4 ,acidify with dilute sulfuric acid measured quantities of a standard solution of potassium iodide in small tubes4 ,add #c or #d drops of the potassium nitrite solution and extract with carbon bisulfide as in the actual determination4 ,transfer to small flasks the standards from which the iodine has been removed4 #e4 ,chlorine water4 ,saturated solution4 #f4 ,bromine standards4 ,add measured quantities of a standard solution of a bromide to the liquid in each of the small flasks from which the iodine has been removed4 ,add to each #e cc4 of purified carbon bisulfide1 and proceed exactly as with the sample4 ,procedure4--,evaporate to dryness an aliquot portion of the alkaline filtrate4 ,dissolve the residue in #b or #c cc4 of water1 and add enough absolute alcohol to make the percentage of alcohol about #ij4 ,boil and filter and repeat the extraction of the residue with alcohol once or twice4 ,add #b or #c drops of sodium hydroxide to the combined alcoholic filtrates and evaporate to dryness4 ,dissolve the residue in #b or #c cc4 of water and repeat the extraction with alcohol and the filtration4 ,add a drop of sodium hydroxide to the filtrate and evaporate it to dryness4 ,dissolve the residue in a little water4 ,acidify this solution with dilute sulfuric acid1 adding #c or #d drops excess1 and transfer it to a small flask4 ,add #d drops of the solution of potassium nitrite or sodium nitrite and about #e cc4 of carbon bisulfide4 ,shake the mixture until all the iodine is extracted4 ,separate the acid solution from the carbon bisulfide by filtration4 ,wash the flask1 filter1 and contents with cold distilled water1 and transfer the carbon bisulfide containing the iodine in solution to ,nessler tubes by means of about #e cc4 of pure carbon bisulfide4 ,in washing the filter1 dilute the contents of the tube to a definite volume1 usually #ab or #ae cc41 and compare the color with that of known amounts of iodine dissolved in carbon bisulfide in other tubes4 ,transfer to a small flask the sample from which the iodine has been removed4 ,add saturated chlorine water1 #a cc4 at a time1 shaking after each addition until all the bromine is freed4 ,care must be taken not to add much more chlorine than that necessary to free the bromine1 since an excess of reagent may form a bromochloride that spoils the color reaction4 ,separate the water solution from the carbon bisulfide by filtration through a moistened filter1 wash the contents of the filter two or three times with water1 and then transfer them to a ,nessler tube by means of about #a cc4 of carbon bisulfide4 ,repeat this extraction of the filtrate twice1 using #c cc4 of carbon bisulfide each time4 ,the combined carbon bisulfide extracts usually amount to #aa4e to #ab cc4 ,add enough carbon bisulfide to the tubes to bring them to a definite volume1 usually #ab to #ae cc41 and compare the sample with the standards4 ,if much bromine is present it is not always completely extracted by the amounts of carbon bisulfide recommended4 ,if the extraction is incomplete1 therefore1 make one or two extra extractions with carbon bisulfide1 transfer the extracts to another tube1 and compare the color with that of the standards4 ,,arsenic4#ca ,evaporate to dryness an aliquot portion of the alkaline filtrate 7p4 #fa74 ,acidify the residue with arsenic-free sulfuric acid1 and subject it to the action of arsenic-free zinc and sulfuric acid in a ,marsh-,berzelius apparatus4 ,compare the mirror obtained with a mirror obtained from an arsenious oxide solution of known strength4 ,,boric ,,acid4 ,evaporate to dryness an aliquot portion of the alkaline filtrate 7p4 #fa71 treat the residue with #a or #b cc4 of water1 and slightly acidify the solution with hydrochloric acid4 ,add about #be cc4 of absolute alcohol1 boil1 filter1 and repeat the extraction of the residue4 ,make the filtrate slightly alkaline with sodium hydroxide1 and evaporate it to dryness4 ,add a little water1 slightly acidify with hydrochloric acid1 and place a strip of turmeric paper in the liquid4 ,evaporate to dryness on the steam bath1 and continue the heating until the turmeric paper is dry4 ,if boric acid is present the turmeric paper becomes cherry red4 ,it is not usually necessary to determine quantitatively boric acid2 the quantitative method devised by ,gooch#cc is recommended4 ,,hydrogen ,,sulfide4#ajc ,hydrogen sulfide should be determined preferably in the field2 the procedure as far as the final titration with sodium thiosulfate must be carried out in the field4 ,reagents4--#a4 ,n_/#ajj sodium thiosulfate4 #b4 ,standard iodine4 ,a ,n_/#ajj solution containing potassium iodide standardized against the ,n_/#ajj sodium thiosulfate4 ,to standardize1 add #aj cc4 of the iodine solution to #ejj cc4 of boiled distilled water4 ,add about #a gram of potassium iodide1 and titrate with ,n_/#ajj sodium thiosulfate in the presence of starch indicator4 ,one cc4 of ,n_/#ajj iodine is equivalent to #j4ag mg4 ,h#b,s4 #c4 ,potassium iodide4 ,crystals4 #d4 ,starch4 ,a freshly prepared solution for use as indicator4 ,procedure4--,add #ejj cc4 of the sample to #aj cc4 of the standard iodine solution and #a gram of potassium iodide in a large glass-stoppered bottle or flask4 ,if the sample is to be collected from a tap lead the water into the bottle through a rubber tube extending to the bottom of the bottle so as to eliminate errors due to aeration4 ,shake the bottle1 allow it to stand for a few minutes1 and then titrate the excess of iodine with sodium thiosulfate in the presence of starch indicator4 ,hydrogen sulfide 7,h#b,s7 in parts per million is equal to #j4cd times the difference in cubic centimeters between the amount of iodine solution added and the amount of ,n_/#ajj thiosulfate used in the titration4 ,,chlorine4 ,in waters that have been treated with calcium hypochlorite or liquid chlorine it is frequently advisable to ascertain the presence or absence of chlorine4 ,as the reagents which have been proposed for its detection are not specific for chlorine but give similar or identical reactions with oxidizing agents or reducible substances care must be exercised in interpreting the results of such tests3 nitrites and ferric salts are of common occurrence1 and chlorates also may lead to misinterpretation in waters treated with calcium hypochlorite4 ,reagents4--#a4 ,tolidin solution4 ,one gram of o-tolidin1 purified by being recrystallized from alcohol1 is dissolved in #a liter of #aj per cent hydrochloric acid4 #b4 ,copper sulfate solution4 ,dissolve #a4e grams of copper sulfate and #a cc4 of concentrated sulfuric acid in distilled water and dilute the solution to #ajj cc4 #c4 ,potassium bichromate solution4 ,dissolve #j4jbe gram of potassium bichromate and #j4a cc4 of concentrated sulfuric acid in distilled water and dilute the solution to #ajj cc4 ,procedure4--,mix #a cc4 of the tolidin reagent with #ajj cc4 of the sample in a ,nessler tube and allow the solution to stand at least #e minutes4 ,small amounts of free chlorine give a yellow and larger amounts an orange color4 ,for quantitative determination compare the color with that of standards in similar tubes prepared from the solutions of copper sulfate and potassium bichromate4 ,the amounts of solution for various standards are indicated in ,table #ac4 ,table #ac4--,,preparation ,,of ,,permanent ,,standards ,,for ,,content ,,of ,,chlorine4 ,chlorine4 ,solution of copper ,solution of potassium sulfate4 bichromate4 ,parts per million4 cc4 cc4 #j4ja #j4j #j4h 4#jb 4#j #b4a 4#jc 4#j #c4b 4#jd 4#j #d4c 4#je 4#d #e4e 4#jf 4#h #f4f 4#jg #a4b #g4e 4#jh #a4e #h4g 4#ji #a4g #i4j 4#aj #a4h #aj4j 4#bj #a4i #bj4j 4#cj #a4i #cj4j 4#dj #b4j #ch4j 4#ej #b4j #de4j ,,dissolved ,,oxygen4#affefhga;b#iiajj;c#abj ,reagents4--#a4 ,sulfuric acid1 concentrated4 7,sp4 gr4 #a4hc-a4hd47 #b4 ,potassium permanganate4 ,dissolve #f4cb grams of the salt in water and dilute the solution to #a liter4 #c4 ,potassium oxalate4 ,a #b per cent solution4 #d4 ,manganous sulfate4 ,dissolve #dhj grams of the salt in water and dilute the solution to #a liter4 #e4 ,alkaline potassium iodide4 ,dissolve #gjj grams of potassium hydroxide and #aej grams of potassium iodide in water and dilute the solution to #a liter4 #f4 ,hydrochloric acid4 ,concentrated 7,sp4 gr4 #a4ah-a4ai74 #g4 ,sodium thiosulfate4 ,a ,n_/#dj solution4 ,dissolve #f4b grams of chemically pure recrystallized sodium thiosulfate in water and dilute the solution to #a liter with freshly boiled distilled water4 ,each cc4 is equivalent to #j4b mg4 of oxygen or to #j4acie cc4 of oxygen at #j;,c4 and #gfj mm4 pressure4 ,inasmuch as this solution is not permanent it should be standardized occasionally against a ,n_/#dj solution of potassium bichromate4 ,the keeping qualities of the thiosulfate solution are improved by adding to each liter #e cc4 of chloroform and #a4e grams of ammonium carbonate before diluting to the prescribed volume4 #h4 ,starch solution4 ,mix a small amount of clean starch with cold water until it becomes a thin paste and stir this mass into #aej to #bjj times its weight of boiling water4 ,boil for a few minutes1 then sterilize4 ,it may be preserved by adding a few drops of chloroform4 ,collection of sample4--,collect the sample in a narrow-necked glass-stoppered bottle of #bej to #bgj cc4 capacity4 ,the following procedure should be followed in order to avoid entrainment or absorption of atmospheric oxygen4 ,in collecting from a tap fill the bottle through a glass or rubber tube extending well into the tap and to the bottom of the bottle4 ,to avoid air bubbles allow the bottle to overflow for several minutes1 and then carefully replace the glass stopper so that no air bubble is entrained4 ,in collecting from the surface of a pond or tank connect the sample bottle to a bottle of #a liter capacity4 ,provide each bottle with a two-hole rubber stopper having one glass tube extending to the bottom and another glass tube entering but not projecting into the bottle4 ,connect the short tube of the sample bottle with the long tube of the liter bottle4 ,immerse the sample bottle in the water and apply suction to the outlet of the liter bottle4 ,to collect a sample at any depth arrange the two bottles so that the outlet tube of the liter bottle is at a higher elevation then the inlet tube of the sample bottle4 ,lower the two bottles1 in any convenient form of cage properly weighted1 to the desired depth4 ,water entering during the descent will be flushed through into the liter bottle4 ,when air bubbles cease rising to the surface raise the bottles4 ,finally replace the perforated stopper of the sample bottle with a glass stopper in such manner as to avoid entraining bubbles of air4 ,procedure4--,remove the stopper from the bottle and add1 first1 #j4g cc4 of the concentrated sulfuric acid1 and then #a cc4 of the potassium permanganate solution4 ,these and all other reagents should be introduced by pipette under the surface of the liquid4 ,insert the stopper and mix by inverting the bottle several times4 ,after #bj minutes have elapsed destroy the excess of permanganate by adding #a cc4 of the potassium oxalate solution1 the bottle being at once restoppered and its contents mixed4 ,if a noticeable excess of potassium permanganate is not present at the end of #bj minutes1 again add #a cc4 of the potassium permanganate solution4 ,if this is still insufficient use a stronger potassium permanganate solution4 ,after the liquid has been decolorized by the addition of potassium oxalate add #a cc4 of the manganous sulfate solution and #c cc4 of the alkaline potassium iodide solution4 ,allow the precipitate to settle4 ,add #b cc4 of the hydrochloric acid and mix by shaking4 ,the procedure to this point must be carried out in the field1 but after the acid has been added and the stopper replaced there is no further change1 and the rest of the test may be performed within a few hours1 as convenient4 ,transfer #bjj cc4 of the contents of the bottle to a flask and titrate with ,n_/#dj sodium thiosulfate1 using a few cubic centimeters of the starch solution as indicator toward the end of the titration4 ,do not add the starch solution until the color has become faint yellow1 and titrate until the blue color disappears4 ,the use of potassium permanganate is made necessary by high nitrite or organic matter4 ,the procedure outlined must be followed in all work on sewage and partly purified effluents or seriously polluted streams or samples whose nitrite nitrogen exceeds #j4a part per million4 ,in testing other samples the procedure may be shortened by beginning with the addition of the manganous sulfate solution and proceeding from that point as outlined1 except that only #a cc4 of alkaline potassium iodide need be added4 ,calculation of ,results4--,oxygen shall be reported in parts per million by weight4 ,it is sometimes convenient to know the number of cubic centimeters per liter of the gas at #j;,c4 temperature and #gfj mm4 pressure and also to know the percentage which the amount of gas present is of the maximum amount capable of being dissolved by distilled water at the same temperature and pressure4 ,if #bjj cc4 of the sample is taken the number of cubic centimeters of ,n_/#dj thiosulfate used is equal to parts per million of oxygen4 ,corrections for volume of reagents added amount to less than #c per cent and are not justified except in work of unusual precision4 ,to obtain the result in cubic centimeters per liter multiply the number of cubic centimeters of thiosulfate used by #j4fih4 ,to obtain the result in percentage of saturation divide the number of cubic centimeters of thiosulfate by the figure in ,table #ad opposite the temperature of the water and under the proper chlorine figure4 ,the last column of ,table #ad permits interpolation for intermediate chlorine values4 ,at elevations differing considerably from mean sea level and for accurate work attention must be given to barometric pressure1 the normal pressure in the region being preferable to the specific pressure at the time of sampling4 ,the term 8saturation0 refers to a condition of equilibrium between the solution and an oxygen pressure in the atmosphere corresponding to #aeh4h millimeters1 or approximately one-fifth atmosphere4 ,the true saturation or equilibrium between the solution and pure oxygen is nearly five times this value1 and consequently values in excess of #ajj per cent saturation frequently occur in the presence of oxygen-forming plants4 ,table #ad4--,,solubility ,,of ,,oxygen ,,in ,,fresh ,,water ,,and ,,in ,,sea ,,water ,,of ,,stated ,,degrees ,,of ,,salinity ,,at ,,various ,,temperatures ,,when ,,exposed ,,to ,,an ,,atmosphere ,,containing #bj4i ,,per ,,cent ,,of ,,oxygen ,,under ,a ,,pressure ,,of #gfj ,,mm4,f 7,calculated by ,g4 ,c4 ,whipple and ,m4 ,c4 ,whipple from measurements of ,c4 ,j4 ,fox47#bgaai ,difference ,temperature4 ,chloride in sea water 7milligrams per per #ajj liter74 parts of chloride4 #j4 #ejjj4 #ajjjj4 #aejjj4 #bjjjj4 ,c4 ,dissolved oxygen in milligrams per liter4 ,parts per million4 #j #ad4fb #ac4gi #ab4ig #ab4ad #aa4cb #j4jafe #a #ad4bc #ac4da #ab4fa #aa4hb #aa4jc 4#jafj #b #ac4hd #ac4je #ab4bh #aa4eb #aj4gf 4#jaed #c #ac4dh #ab4gb #aa4ih #aa4bd #aj4ej 4#jadi #d #ac4ac #ab4da #aa4fi #aj4ig #aj4be 4#jadd #e #ab4hj #ab4ji #aa4ci #aj4gj #aj4ja 4#jadj #f #ab4dh #aa4gi #aa4ab #aj4de #i4gh 4#jace #g #ab4ag #aa4ea #aj4he #aj4ba #i4eg 4#jacj #h #aa4hg #aa4bd #aj4fa #i4ih #i4cf 4#jabe #i #aa4ei #aj4ig #aj4cf #i4gf #i4ag 4#jaba #aj #aa4cc #aj4gc #aj4ac #i4ee #h4ih 4#jaah #aa #aa4jh #aj4di #i4ib #i4ce #h4hj 4#jaad #ab #aj4hc #aj4bh #i4gb #i4ag #h4fb 4#jaaj #ac #aj4fj #aj4je #i4eb #h4ih #h4df 4#jajg #ad #aj4cg #i4he #i4cb #h4hj #h4cj 4#jajd #ae #aj4ae #i4fe #i4ad #h4fc #h4ad 4#jajj #af #i4ie #i4df #h4if #h4dg #g4ii 4#jjih #ag #i4gd #i4bf #h4gh #h4cj #g4hd 4#jjie #ah #i4ed #i4jg #h4fb #h4ae #g4gj 4#jjib #ai #i4ce #h4hi #h4de #h4jj #g4ef 4#jjhi #bj #i4ag #h4gc #h4cj #g4hf #g4db 4#jjhh #ba #h4ii #h4eg #h4ad #g4ga #g4bh 4#jjhf #bb #h4hc #h4db #g4ii #g4eg #g4ad 4#jjhe #bc #h4fh #h4bg #g4he #g4dc #g4jj 4#jjhc #bd #h4ec #h4ab #g4ga #g4cj #f4hg 4#jjhc #be #h4ch #g4if #g4ef #g4ae #f4gd 4#jjhb #bf #h4bb #g4ha #g4db #g4jb #f4fa 4#jjhj #bg #h4jg #g4fg #g4bh #f4hh #f4di 4#jjgi #bh #g4ib #g4ec #g4ad #f4ge #f4cg 4#jjgh #bi #g4gg #g4ci #g4jj #f4fb #f4be 4#jjgf #cj #g4fc #g4be #f4hf #f4di #f4ac 4#jjge ,footnote ,f3 ,under any other barometric pressure1 ,b1 the solubility can be obtained from the corresponding value in the table by the formula3 ,s ,s7,b_/#gfj7 ,s7,b_/#bi4ib7 in which ,s ,solubility at ,b or ,b1 ,s ,solubility at #gfj mm4 or #bi4ib inches1 ,b ,barometric pressure in mm41 and ,b ,barometric pressure in inches4 ,,ether-,,soluble ,,matter4#dd ,evaporate #ejj cc4 of the sample in a porcelain evaporating dish to a volume of about #ej cc4 ,by means of a rubber-tipped glass rod remove to the bottom of the dish the solid matter attached to the sides1 and add normal sulfuric acid to neutralize the alkalinity4 ,do not use an excess of acid4 ,then evaporate the contents of the dish to dryness4 ,treat the dry residue with boiling ether1 rubbing the bottom and sides of the dish to insure complete solution of fat4 ,three extractions with ether are required4 ,filter the ether solution through a #e cm4 filter into a weighed flask having a wide mouth4 ,evaporate the ether slowly1 and dry the flask at #ajj ,c4 for #cj minutes4 ,the increase in weight of the flask gives the amount of fats1 or1 in more precise language1 the ether-soluble matter4 ,an excess of acid gives too high results because of the formation of fatty-acid residues4 ,,relative ,,stability ,,of ,,effluents4#gh ,reagent4--,methylene blue solution4 ,a #j4je per cent aqueous solution of methylene blue1 preferably the double zinc salt or commercial variety4#fj;b ,collection of sample4--,collect the sample in a glass-stoppered bottle holding approximately #aej cc4 ,if the dissolved oxygen is low observe precautions similar to those used in collecting samples for dissolved oxygen 7p4 #ff74 ,procedure4--,add #j4d cc4 of the methylene blue solution to the sample in the #aej cc4 bottle4 ,as methylene blue has a slightly antiseptic property be careful to add exactly #j4d cc4 ,add the methylene blue solution preferably below the surface of the liquid after filling the bottle with the sample4 ,if the methylene blue is added first do not allow the liquid to overflow as coloring matter will thus be lost4 ,incubate the sample at #bj ,c4 for ten days4 ,four days' incubation may be considered sufficient for all practical purposes in routine plant-control work4 ,if quick results are desired incubate the sample at #cg ,c4 for five days using suitable stoppers#a;a#b;a to prevent the loss and reabsorption of dissolved oxygen4 ,the bacterial flora at #cg ,c4 is different from that at #bj ,c4 ,the lower temperature is more nearly the average temperature of surface waters and therefore the higher temperature should be used only when quick approximate results are essential4 ,observe the sample at least twice a day during incubation4 ,give a sample in which the methylene blue becomes decolorized a relative stability corresponding to the time required for reduction 7see ,table #ae74 ,for routine filter control ordinary room or cellar temperature gives fairly satisfactory results4 ,for accurate studies1 room temperature incubation is very undesirable1 as the fluctuations in temperature which are ordinarily not noticed are responsible for appreciable deviations from the true values of relative stability4 ,if the samples are incubated less than #aj days at #bj ,c4 and are not decolorized place a plus sign after the stability value in order to indicate that the stability might have been higher if more time had been allowed4 ,in applying this test to river waters it often happens that the blue coloring matter is removed either partly or completely through absorption by the clay which many rivers carry in suspension4 ,true relative stabilities cannot be obtained for such waters except by determining the initial available oxygen at the start and the biochemical oxygen demand on incubation at #bj ,c4 for #aj days 7pp4 #ga-gc74 ,germicides1 such as hypochlorite of lime1 if present in sufficient quantity1 vitiate the results4 ,if a sample contains free chlorine1 therefore1 store it about #b hours1 or until the chlorine is gone1 and then add methylene blue4 ,table #aegh gives the relation between the time in days to decolorize methylene blue at #bj ,c4 7t#bj7 and the relative stability number or ratio of available oxygen to oxygen required for equilibrium1 expressed in percentage 7,s74 ,table #ae4--,,relative ,,stability ,,numbers4 ,time required for decolorization at ,relative stability4 #bj ,c4 ,days4 ,percentage4 #j4e #aa #a4j #ba #a4e #cj #b4j #cg #b4e #dd #c4j #ej #d4j #fj #e4j #fh #f4j #ge #g4j #hj #h4j #hd #i4j #hg #aj4j #ij #aa4j #ib #ab4j #id #ac4j #ie #ad4j #if #af4j #ig #ah4j #ih #bj4j #ii ,the theoretical relation is1 ,s #ajj 7#a #j4gidt#bj7 ,the relation between the time of reduction at #bj ,c4 and that at #cg ,c4 is approximately two to one1 but if an observer incubates at #cg ,c4 he should work out his own comparative #cg ,c4 table or factor4 ,a relative stability of #ge signifies that the sample examined contains a supply of available oxygen equal to #ge per cent of the amount of oxygen which it requires in order to become perfectly stable4 ,the available oxygen is approximately equivalent to the dissolved oxygen plus the available oxygen of nitrate and nitrite4 ,nitrite in sewage is usually so low as to be negligible4 ,,biochemical ,,oxygen ,,demand ,,of ,,sewage ,,and ,,effluents4#fj;a#fj;c#fj;d ,,relative ,,stability ,,method4 ,the relative stability method may be employed to obtain a measure of the putrescible material in sewages and effluents in terms of oxygen demand4 ,procedure for effluents4--,divide the total available oxygen1 including the oxygen of nitrite and nitrate1 by the relative stability expressed as a decimal4 ,procedure for sewages4--,make one or two dilutions with fully aerated distilled water of known dissolved oxygen content4 ,tap water may be employed if it is free from nitrates4 ,vary the relative proportions of sewage and water to be employed to give a relative stability of #ej to #ge4 ,unless seals#a;b#b;b#eb;a are used bring the water as well as the sewage to the temperature at which the mixtures are to be incubated before preparing the dilutions4 ,during the manipulation avoid aeration4 ,having made the proper dilutions1 determine the relative stability of each4 ,calculate the oxygen demand in parts per million by the formula3 ,oxygen demand ,o7#a p7_/,rp ,in this formula1 ,o is the initial dissolved oxygen of the diluting water1 p is the proportion of sewage2 and ,r is the relative stability of the mixture4 ,ordinarily the available oxygen in crude sewages1 septic tank effluents1 settling tank effluents1 and trade wastes can be neglected4 ,,sodium ,,nitrate ,,method4 ,for the determination of the biochemical oxygen demand the sodium nitrate method may be used#fj;a#fj;c#fj;d#eb;a4 ,the method is based on the biochemical consumption of oxygen from sodium nitrate by a sewage or polluted water during an incubation period of ten days at #bj ,c4 ,a reasonable excess of sodium nitrate does not give a higher oxygen demand1 as do higher dilutions with aerated water4 ,the oxygen absorbed from the air in applying the method to sewages is negligible4 ,reagent4--,sodium nitrate solution4 ,dissolve #bf4ef grams of pure sodium nitrate in #a liter of distilled water4 ,one cc4 of this solution in #bej cc4 of sewage represents #ej parts per million of available oxygen4 ,the strength of the sodium nitrate solution may be varied to suit conditions4 ,procedure for sewages4--,ordinarily disregard the initial available oxygen as it is very small compared with the total biochemical oxygen demand4 ,add measured amounts of the sodium nitrate solution to the sewage in bottles holding approximately #bej cc4 which have been completely filled and stoppered4 ,incubate for #aj days at #bj ,c4 ,a seal is not required during incubation4 ,the appearance of a black sediment and the development of a putrid odor during incubation indicates that too little sodium nitrate has been added4 ,methylene blue solution in proper proportion may be added at the start to serve as an indicator during the incubation4 ,domestic sewage usually varies in its oxygen demand from #ajj to #cjj parts per million1 approximately #cj per cent of which is used up at #bj ,c4 in the first #bd hours4 ,at the end of the incubation period determine the residual nitrite and nitrate4 ,determine the nitrate by the aluminium reduction method and direct ,nesslerization4 ,to convert the nitrogen into oxygen equivalents1 multiply the nitrite nitrogen by #a4g and the nitrate nitrogen by #b4i4 ,the difference between the available oxygen added as sodium nitrate and that found as nitrite and nitrate at the end of the incubation period is the biochemical oxygen demand4 ,procedure for industrial wastes4--,employ the same procedure using larger quantities of the sodium nitrate solution4 ,make the reaction alkaline to methyl orange and acid to phenolphthalein4 ,adjust an acid reaction with sodium bicarbonate and a caustic alkaline reaction with weak hydrochloric acid4 ,if the liquid is devoid of sewage bacteria seed it with sewage after adjusting the reaction4 ,procedure for polluted river waters4--,determine the initial available oxygen4 ,unless the river water is badly polluted add #aj parts per million of sodium nitrate oxygen4 ,collect carefully1 avoiding aeration1 three samples in #bej cc4 bottles4 ,to one sample add a definite quantity of sodium nitrate solution and incubate4 ,incubate the other two samples for the determination of the residual free oxygen1 nitrite1 and nitrate4 ,if there is free oxygen left1 the bottle containing the sodium nitrate solution may be discarded4 ,if there is no free oxygen determine residual nitrite and nitrate as directed under the procedure for sewage 7p4 #gb7 and calculate the oxygen demand4 ,,analysis ,,of ,,sewage ,,sludge ,,and ,,mud ,,deposits4 ,,collection ,,of ,,sample4 ,collect a representative sample of the material4 ,in general more than one sample should be taken from a spot and a large number of samples should be collected rather than a few large samples4 ,if the surface layer is darker and a lower layer consists of pure clay sample only the surface layer4 ,samples may be analyzed either separately or as composites of careful mixtures4 ,after the sample has settled a few minutes roughly drain or siphon the excess water4 ,allow sewage sludge to stand for one hour before draining it free from excess water unless it is essential to determine the moisture content of the sample originally collected4 ,if sludge cannot be analyzed within twenty-four hours it is better not to use air-tight bottles and to add small quantities of chloroform and keep in the ice box to retard decomposition4 ,at the time of collection carefully examine mud from the bottom of surface water for evidence of sewage pollution and macroscopic and microscopic animal and plant organisms4 ,record the predominant species4 ,note the physical appearance of the material1 particularly its color1 odor1 and consistency4 ,express all analytical results in percentage on a dry basis4 ,,reaction4 ,determine the reaction by diluting a definite quantity of the wet sludge and titrating by the methods given under alkalinity and acidity 7pp4 #ce-ci and #ci-da74 ,,specific ,,gravity4 ,weigh to the nearest tenth of a gram a wide-mouthed flask of #ajj to #cjj cc4 capacity1 according to the quantity of material available4 ,then completely fill the flask with distilled water to the brim and weigh it again4 ,empty the flask and fill it completely with fresh sewage sludge or mud4 ,if the material is of such consistency that it flows readily fill the flask to the brim and weigh4 ,the specific gravity is equal to the weight of the sludge or mud divided by the weight of an equal volume of distilled water4 ,if the material does not flow readily fill the weighed flask as completely as possible without exerting pressure during the procedure4 ,weigh and then fill the flask to the brim with distilled water4 ,let it stand for a few minutes1 until trapped air has escaped1 then add more water if necessary and weigh4 ,subtract the weight of the added water from the weight of the water that completely fills the flask2 the specific gravity is equal to the weight of the material divided by this difference4 ,record the specific gravity only to the second decimal place4 ,,moisture4 ,heat approximately #be grams of sludge or mud in a weighed nickel dish on the water bath until it is fairly dry4 ,dry the residue in an oven at #ajj ,c41 cool1 and weigh4 ,repeat to approximate constant weight4 ,the loss in weight is moisture4 ,,volatile ,,and ,,fixed ,,matter4 ,ignite1 at dull red heat in a hood1 the residue from the determination of moisture until all the carbon has disappeared4 ,cool the residue in a desiccator and weigh it4 ,the residue is the fixed matter4 ,the volatile matter is the difference in weight between the original dried sludge and the ignited sludge4 ,,total ,,organic ,,nitrogen4 ,preparation of sample4--,for the determination of organic nitrogen and fats dry approximately #ej to #ge grams of the sludge or mud in a porcelain dish first on the water bath and finally in the hot-water oven until all the moisture has disappeared4 ,grind the dry material to a fine powder and keep it in a glass-stoppered bottle4 ,reagents4--#a4 ,sulfuric acid4 ,concentrated1 nitrogen-free4 #b4 ,copper sulfate solution4 ,ten per cent4 #c4 ,potassium permanganate4 ,crystals4 ,first procedure4--,weigh accurately #j4e gram of dried sludge or #e4j grams of dried mud and put it into a #ejj cc4 ,kjeldahl flask4 ,digest it with #bj cc4 of sulfuric acid1 or more if necessary1 and #a cc4 of copper sulfate solution to assist the oxidation4 ,boil for several hours until the liquid becomes colorless or slightly yellow4 ,oxidize the residue with #j4e gram of potassium permanganate1 and follow the 8,procedure for ,sewage0 7pp4 #ba-bb74 ,second procedure4--,the following method is convenient for routine work at sewage disposal plants4 ,after digestion as described in the first procedure1 cool1 transfer to a glass-stoppered #ajj cc4 flask1 dilute with distilled water to #ajj cc41 and mix well4 ,transfer #ej cc4 with a pipette into another #ajj cc4 volumetric flask1 and make this portion alkaline with #ej per cent sodium hydroxide1 testing a drop of the liquid on a porcelain plate with phenolphthalein to insure neutralization4 ,the formation of a floc usually indicates that neutralization is complete4 ,dilute the solution to #ajj cc41 pour it into a small glass-stoppered bottle and permit it to stand until the next day4 ,nesslerize an aliquot portion of the clear supernatant liquid1 and calculate the percentage of nitrogen in the material4 ,,ether-,,soluble ,,matter4 ,fats are usually determined only on sewage sludge1 but some mud deposits contain small quantities due to the presence of trade wastes4 ,procedure4--,weigh #j4e to #be grams of dry material according to the quality of the sludge or mud4 ,add water to the weighed portion in a porcelain dish and acidify the mixture with ,n_/#ej sulfuric acid in the presence of litmus tincture or azolitmin solution as indicator4 ,avoid adding too much acid as an excess gives too high results on account of fatty acid residues4 ,evaporate the acidified mixture to dryness on the water bath1 and heat it in the hot air oven at #ajj ,c4 two to three hours4 ,extract the dry residue with boiling ether1 rubbing the sides and bottom of the dish to insure complete solution of the fat4 ,three extractions with ether are usually sufficient4 ,filter the ether solution through a #e cm4 filter paper into a small flask4 ,evaporate the ether slowly1 dry the fatty extract for half an hour at #ajj ,c41 cool in a desiccator1 and weigh4 ,if it is desirable1 particularly with certain industrial wastes1 to determine the quantity of saponified fat determine the fats with and without the addition of acid4 ,the difference between the quantities found by the two determinations is the content of saponified fat4 ,,ferrous ,,sulfide4 ,the liberation of hydrogen sulfide on adding dilute hydrochloric acid to a sludge indicates the presence of ferrous sulfide4 ,as ferrous sulfide quickly oxidizes on exposure to air a quantitative determination of this constituent must be made immediately after collection of the sample4 ,procedure4--,heat a definite portion of the sludge with hydrochloric acid in a flask4 ,pass the liberated gas through bromine water or hydrogen peroxide4 ,determine gravimetrically the sulfate in the oxidizing solution1 and calculate the equivalent of ferrous sulfide by multiplying the weight of barium sulfate by #j4cgf4 ,,biochemical ,,oxygen ,,demand4 ,the quantity of river mud most suitable for the determination of the biochemical oxygen demand ranges within certain limits1 largely according to the amount of oxidizable matter present4 ,for examinations of river mud prepare a #a per cent stock suspension in distilled water or tap water saturated with oxygen and free from nitrate2 use in the test a dilution of this stock suspension equivalent to a concentration of #a to #aj grams per liter of mud4 ,for examinations of fresh sewage sludge prepare a #a per cent stock suspension in a similar manner1 but use in the test a dilution equivalent to only #j4a to #a4j gram per liter of wet material4 ,for examinations of dried sludges1 which have undergone more or less oxidation higher concentrations may be required4 ,procedure4--,place a measured portion of the sample1 or the proper amount of the #a per cent stock suspension of the sample1 in a #cjj cc4 narrow-mouth glass-stoppered bottle1 and dilute it to the desired concentration with water saturated with oxygen4 ,determine the oxygen content at #bj ,c4 of the waters that are used for dilution4 ,this determination must be made before the mud or sludge is added because iron sulfide in the mud or sludge rapidly consumes part of the dissolved oxygen4 ,incubate at #bj ,c4 for five days4 ,shortly before the determination of the oxygen remaining in solution at the end of five days rotate the bottle once or twice to mix its contents and allow sedimentation for about #cj minutes4 ,siphon the greater part of the liquid through a narrow-bore siphon into a #aej cc4 bottle1 which has been filled with carbon dioxide4 ,reject the first #be cc4 of the siphoned liquid and allow a little to overflow at the end of siphoning4 ,determine the oxygen content of the solution in the bottle in the usual way 7pp4 #fe-fh74 ,report the oxygen demand in percentage of the dried mud or sludge4 ,,analysis ,,of ,,chemicals4 ,the following sections describe the accepted methods for the analysis of the chemicals commonly used in the treatment of water4 ,,reagents4 #a4 ,distilled water4 ,in practically all the tests of chemicals it is necessary to use exclusively distilled water that has been freshly boiled to free it from carbon dioxide and oxygen4 #b4 ,concentrated hydrochloric acid4 ,sp4 gr4 #a4bj4 #c4 ,hydrochloric acid1 ,n_/#b4 #d4 ,hydrochloric acid1 ,n_/#aj4 #e4 ,ammonium hydroxide4 ,redistilled2 sp4 gr4 #j4ij4 #f4 ,dilute sulfuric acid4 ,dilute #a part of concentrated sulfuric acid with #c parts of freshly boiled distilled water4 #g4 ,methyl orange indicator4 ,see page #cf4 #h4 ,phenolphthalein indicator4 ,see page #cf4 #i4 ,bromine water4 #aj4 ,stannous chloride1 ,n_/#bj4 ,this should be frequently standardized by titration against a standard iron solution4 ,one cc4 of ,n_/#bj stannous chloride is equal to #j4jjbh gram of iron 7,fe7 estimated in the ferrous state4 #aa4 ,sodium hydroxide1 ,n_/#a4 ,free from carbonate4 ,this should be frequently standardized by titration against a standard acid solution in presence of phenolphthalein indicator4 ,one cc4 of ,n_/#a sodium hydroxide is equal to #j4jdi gram of sulfuric acid 7,h#b,,so#d71 or to #j4jcfde gram of hydrochloric acid 7,h,cl74 #ab4 ,sodium hydroxide1 ,n_/#bj4 ,free from carbonate4 #ac4 ,standard potassium permanganate4 ,a ,n_/#aj solution4 ,one cc4 of ,n_/#aj potassium permanganate is equal to #j4jjef gram of iron 7,fe7 estimated in the ferrous state4 #ad4 ,alcohol4 ,ethyl alcohol1 #ie per cent4 #ae4 ,sugar4 ,solid granulated cane sugar4 ,,sulfate ,,of ,,aluminium4 ,determine and report insoluble matter1 aluminium oxide 7,al#b,o#c71 ferric oxide 7,fe#b,o#c71 ferrous oxide 7,fe,o71 basicity ratio1 and1 if present1 free acid as ,h#b,,so#d4 ,if the material is what is known as 8granular0 sulfate mix it well before sampling4 ,if it is in lump form crush it to to inch size1 mix1 and sample it4 ,it is unnecessary to grind the sample to a fine powder1 but it is preferable to have the particles fairly uniform in size4 ,,insoluble ,,matter4 ,treat #aj grams of the sample with #ajj cc4 of distilled water and digest one hour at boiling temperature4 ,filter through a weighed ,gooch crucible and wash the insoluble matter with hot water freshly boiled to free it from carbon dioxide4 ,dry the crucible to constant weight at #ajj ,c41 cool1 and weigh4 ,report the percentage of insoluble matter4 ,,oxides ,,of ,,iron ,,and ,,aluminium4 ,dilute the filtrate from the determination of insoluble matter to #ejj cc4 with water free from carbon dioxide and thoroughly mix the solution4 ,transfer #ej cc4 of the solution to a #bej cc4 beaker1 add about #aej cc4 of water and #e cc4 of concentrated hydrochloric acid1 and heat to boiling4 ,add ammonium hydroxide in slight excess2 when the solution has been almost neutralized it is convenient to add a drop of methyl orange indicator and then to add about #j4e cc4 of ammonium hydroxide after the solution is neutral to the indicator4 ,digest at about #ajj ,c4 for a few minutes and filter4 ,some analysts prefer to wash this gelatinous precipitate with hot water by decantation1 and some to wash it evenly distributed over the surface of a filter paper2 either method may be used4 ,it is difficult to free it completely from impurities and it is not necessary to do so unless unusual quantities of calcium1 magnesium1 sodium1 or potassium are present4 ,while the precipitate is being washed do not allow it to become dry1 as it then packs and can not be washed clean4 ,after most of the water has drained drying the filter may be hastened by placing it on a sheet of blotting paper4 ,if much iron is present completely dry the precipitate1 remove it from the paper1 and ignite the paper separately4 ,finally1 blast the precipitate1 with free access of air to the crucible1 for five or ten minutes1 cool1 and weigh as oxides of iron and aluminium 7,fe#b,o#c ,al#b,o#c74 ,subtract the content of total iron1 expressed as ferric oxide 7,fe#b,o#c71 from the weight of the combined oxides and report the difference as aluminium oxide 7,al#b,o#c71 in percentage4 ,,total ,,iron4 ,as filter alum usually contains #j4b to #j4c per cent of iron use a #aj gram sample for the determination of total iron4 ,treat the sample with #ej cc4 of freshly boiled distilled water and add #e cc4 of concentrated hydrochloric acid and #a cc4 of bromine water4 ,evaporate the solution to dryness1 dissolve the residue in water1 and wash it into a flask with sufficient water to make the volume about #ej cc4 ,add #ej cc4 of concentrated hydrochloric acid1 boil to expel oxygen1 and titrate1 as hot as possible1 with ,n_/#bj stannous chloride4 ,if a #aj gram sample is used the percentage of iron 7,fe7 is equal to the number of cubic centimeters of stannous chloride used multiplied by #j4jbh1 and the percentage of iron expressed as ferric oxide is equal to the number of cubic centimeters of stannous chloride used multiplied by #j4jdj4 ,,ferric ,,iron4 ,as filter alum usually contains #j4jb to #j4jd per cent of ferric iron use a #bj gram sample4 ,boil #ej cc4 of distilled water to expel oxygen1 add #ej cc4 of concentrated hydrochloric acid1 and add the sample while the solution is boiling4 ,keep it boiling till the sample is dissolved4 ,the flask should be kept filled with carbon dioxide during this process by dropping in occasionally small amounts of sodium carbonate4 ,when solution of the sample is complete titrate it hot immediately with ,n_/#bj stannous chloride4 ,if a #bj gram sample is used the percentage of ferric oxide 7,fe#b,o#c7 is equal to the number of cubic centimeters of stannous chloride used multiplied by #j4jbj4 ,,ferrous ,,iron4 ,the content of ferrous iron is the difference between total and ferric iron4 ,the percentage of ferrous oxide 7,fe,o7 is1 therefore1 equal to #j4ij times the difference between the percentage of total iron expressed as ferric oxide and the percentage of ferric iron expressed as ferric oxide4 ,report the percentage of ferrous oxide 7,fe,o74 ,,basicity ,,ratio4 ,transfer #ej cc4 of the filtrate from the determination of insoluble matter to a #bjj cc4 casserole and dilute it to #ajj cc4 ,boil the solution and titrate it at boiling temperature with ,n_/#a sodium hydroxide in presence of phenolphthalein indicator4 ,the percentage of acidity in equivalent of sulfuric acid 7,h#b,,so#d7 is equal to the number of cubic centimeters of sodium hydroxide used multiplied by #d4i4 ,in this titration iron and aluminium are precipitated as hydroxides and any free acid is neutralized4 ,calculate the percentage of sulfuric acid equivalent to the determined percentages of aluminium oxide1 ferric oxide1 and ferrous oxide by the following formula3 #b4hh ,al#b,o#c #a4hc ,fe#b,o#c #a4cf ,fe,o4 ,if this percentage of acid equivalent is less than that found by titration report the difference as percentage of free acid4 ,if the percentage of acid equivalent is greater than that found by titration the difference divided by #b4hh is the percentage equivalent to the excess of aluminium oxide present4 ,divide this excess by the percentage of total aluminium oxide and report the quotient as the basicity ratio4 ,,lime4 ,mix well the sample1 which should contain no lumps4 ,if foreign matter is present grind the sample to pass a #ajj-mesh sieve4 ,place #bj grams of granulated cane sugar and #a gram of the sample in a #bej cc4 glass-stoppered bottle1 tightly stopped1 and mix the mass by rolling4 ,do not shake hard as much of the lime could thus be lost as dust4 ,then add #ahg4d cc4 of distilled water freshly boiled to expel carbon dioxide4 ,this makes #bjj cc4 of sugar solution4 ,the lime is mixed dry with the sugar and the water added later to keep the lime from lumping4 ,after shaking the sugar solution one hour titrate #ej cc4 of it with ,n_/#b hydrochloric acid in presence of methyl orange indicator4 ,the acid used is equivalent to the carbonate and hydroxide in #j4be gram of the sample4 ,filter the remainder of the sugar solution1 discarding the first #be cc4 of filtrate4 ,titrate #ej cc4 of the filtrate with ,n_/#b hydrochloric acid in presence of methyl orange indicator4 ,the acid used is equivalent to the hydroxide in #j4be gram of the sample4 ,if a #a gram sample is used the percentage of calcium oxide 7,ca,o7 is equal to #e4f times the number of cubic centimeters of hydrochloric acid used in the second titration2 and the percentage of calcium carbonate 7,ca,c,o#c7 equivalent to the carbonate present is equal to #aj times the difference in cubic centimeters between the results of the two titrations4 ,,sulfate ,,of ,,iron4 ,,insoluble ,,matter4 ,treat #aj grams of the sample with #ajj cc4 of freshly boiled distilled water cooled to #cj ,c4 or less4 ,when solution is complete filter through a weighed ,gooch crucible1 wash1 dry1 cool1 and weigh4 ,report the weight of the residue1 in percentage1 as insoluble matter4 ,,iron ,,as ,,ferrous ,,sulfate4 ,dissolve #a gram of the sample and dilute to #bjj cc4 with freshly boiled distilled water cooled to #cj ,c4 or less4 ,add #e cc4 of dilute sulfuric acid 7#a to #c7 to a #ej cc4 portion of the solution and titrate with ,n_/#aj potassium permanganate4 ,the percentage of ferrous sulfate 7,fe,s,o#d4g;,h#b,o7 is equal to #aa4ab times the number of cubic centimeters of potassium permanganate used4 ,,acidity4 ,shake #ab4be grams of the sample in a #aej cc4 bottle with #ge cc4 of #ie per cent alcohol for ten minutes4 ,run a blank4 ,filter rapidly both sample and blank and wash rapidly with alcohol sufficient to make #ajj cc4 of filtrate4 ,titrate with ,n_/#bj sodium hydroxide in presence of phenolphthalein and subtract the result of titrating the blank from that of titrating the solution of the sample4 ,the percentage of acidity1 expressed as sulfuric acid 7,h#b,,so#d71 is equal to #j4jb times the number of cubic centimeters of sodium hydroxide used4 ,,soda ,,ash4 ,,insoluble ,,matter4 ,treat #e4cje grams of the sample with #bjj cc4 of freshly boiled and cooled distilled water4 ,when solution is complete filter through an asbestos mat in a weighed ,gooch crucible1 dry1 cool1 and weigh4 ,report the weight of the residue1 in percentage1 as insoluble matter4 ,,available ,,alkali4 ,dilute the filtrate from the determination of insoluble matter to #a1jjj cc4 and thoroughly mix4 ,titrate #be cc4 of this dilution with ,n_/#aj hydrochloric acid in presence of methyl orange indicator4 ,the percentage of available alkali1 expressed as sodium carbonate 7,na#b;,,co#c71 is equal to #d times the number of cubic centimeters of hydrochloric acid used4 ,,chemical ,,bibliography4 ,the subjoined bibliography comprises the publications cited in the text of this report4 ,the references are arranged alphabetically by authors' names and under each author in order of dates of publication4 ,when different pages of a single work are cited letters are used in connection with the number that refers to the work4 ,bibliography #a3 ,,andrews1 ,l4 ,w4 ,sprengel's method for colorimetric determination of nitrates3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bf1 pp4 #chh-ia1 #aijd4 ,bibliography #a;a3 a4 ,,assoc4 ,,off4 ,,ag4 ,,chemists4 ,determination of iodine and bromine3 ,j4 ,a4 ,o4 ,a4 ,c41 ,vol4 #a1 ,no4 #d1 pt4 #a1 pp4 #dg-h1 #aiaf4 ,bibliography #a;b3 b4 ,,bachmann1 ,,frank4 ,a new seal for the prevention of aeration in deaerated liquids3 ,j4 ,ind4 ,eng4 ,chem41 ,vol4 #f1 pp4 #gfd-e1 #aiad4 ,bibliography #b3 ,,bartow1 ,,edward1 and ,,rodgers1 ,j4 ,s4 ,determination of nitrates by reduction with aluminium3 ,am4 ,j4 ,public ,hygiene1 new ser41 ,vol4 #e1 pp4 #ecf-dd1 #aiji2 also ,illinois ,univ4 ,bull41 ,vol4 #g1 ,no4 #b 7,water ,survey ,ser4 ,no4 #g71 pp4 #ad-bg1 #aiji4 ,bibliography #b;a3 a4 ,,blinn1 ,,william4 ,determination of manganese as sulfate and by the sodium bismuthate method3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #cd1 pp4 #acgi-ih1 #aiab4 ,bibliography #b;b3 b4 ,,buswell1 ,a4 ,m4 ,modified apparatus for the putrescibility test3 ,j4 ,ind4 ,eng4 ,chem41 ,vol4 #f1 p4 #cbe1 #aiad4 ,bibliography #c3 ,,caldwell1 ,g4 ,c4 ,a method in part for the sanitary examination of water and for the statement of results1 offered for general adoption3 ,j4 ,anal4 ,chem41 ,vol4 #c1 pp4 #cih-djc1 #ahhi4 ,bibliography #d3 ,,calkins1 ,g4 ,n4 ,a study of odors observed in the drinking waters of ,massachusetts3 ,report ,mass4 ,state ,board of ,health1 pp4 #cee-hj1 #ahib4 ,bibliography #e3 ,,chamot1 ,e4 ,m41 and ,,pratt1 ,d4 ,s4 ,a study on the phenoldisulfonic acid method for the determination of nitrates in water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #ca1 pp4 #ibb-h1 #aiji2 ,vol4 #cb1 pp4 #fcj-g1 #aiaj2 and ,,redfield1 ,h4 ,w41 ,vol4 #cc1 pp4 #cff-ha1 #cha-d1 #aiaa4 ,bibliography #f3 ,,clark1 ,h4 ,w4 ,experiments upon the purification of sewage and water at the ,lawrence ,experiment ,station3 ,report ,mass4 ,state ,board of ,health1 pp4 #dbg-egh1 #ahif4 ,bibliography #g3 ,,clark1 ,h4 ,w41 and ,,forbes1 ,f4 ,b4 ,methods for the determination of lead1 tin1 zinc1 and copper in drinking waters3 ,report ,mass4 ,state ,board of ,health1 pp4 #egg-he1 #ahih2 pp4 #dih-ejf1 #aijj4 ,bibliography #h3 ,,cohn1 ,a4 ,i4 ,tests and reagents1 #ast ed41 p4 #baf1 ,john ,wiley ,sons1 ,new ,york1 #aijc4 ,bibliography #i3 ,,dibdin1 ,w4 ,j4 ,the purification of sewage and water1 #c;d ed41 pp4 #cde-ea1 ,d4 ,van ,nostrand ,co41 ,new ,york1 #aijc4 ,bibliography #aj3 ,,dole1 ,r4 ,b4 ,the quality of the surface waters in the ,united ,states3 ,u4 ,s4 ,geol4 ,survey ,water-,supply ,paper #bcf1 pp4 #ae-i1 #aiji4 ,bibliography #aa3 ,,draper1 ,h4 ,n4 ,lacmoid and carminic acid as reagents for alkalies3 ,chem4 ,news1 ,vol4 #ea1 pp4 #bjf-g1 #ahhe4 ,bibliography #ac3 ,,drown1 ,t4 ,m41 and ,,martin1 ,,henry4 ,determination of organic nitrogen in natural waters by the ,kjeldahl method3 ,tech4 ,quart41 ,vol4 #b1 ,no4 #c2 ,chem4 ,news1 ,vol4 #ei1 pp4 #bgb-f1 #ahhi4 ,bibliography #ad3 ,,drown1 ,t4 ,m4 ,the chemical examination of waters and the interpretation of analyses3 ,examinations by the ,state ,board of ,health of water supplies of ,mass4 #ahhg-ij1 pt4 #a1 ,examination of water supplies1 pp4 #eai-gh1 #ahij4 ,bibliography #ae3 ----4 ,report upon the examination of the outlets of sewers and the effect of sewage disposal in ,massachusetts3 ,report ,mass4 ,state ,board of ,health1 pp4 #bhe-deb1 #aijb4 ,bibliography #af3 ----1 and ,,hazen1 ,,allen4 ,a report of the chemical work done at the ,lawrence ,experiment ,station3 ,examinations by the ,state ,board of ,health of water supplies of ,mass4 #ahhg-ij1 pt4 #b1 ,purification of sewage and water1 pp4 #gjg-cd1 #ahij4 ,bibliography #ag3 ,,dupre1 ,dr4 ,some observations on the permanganate test in water analysis3 ,analyst1 ,vol4 #aj1 pp4 #aah-bb1 #ahhe4 ,bibliography #ah3 ,,ellms1 ,j4 ,w4 ,a study of the relative value of lacmoid1 phenacetolin1 and erythrosine as indicators in the determination of the alkalinity of water by ,hehner's method3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #ba1 pp4 #cei-fi1 #ahii4 ,bibliography #bj3 ----1 and ,,beneker1 ,j4 ,c4 ,the estimation of carbonic acid in water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bc1 pp4 #dje-ca1 #aija4 ,bibliography #ba3 ,,farnsteiner1 ,,buttenburg1 and ,,korn1 ,leitfaden fr die chemische ,untersuchung von ,abwasser1 ,berlin1 p4 #bj1 #aijb4 ,bibliography #bb3 ,,fitzgerald1 and ,,foss1 ,report ,boston ,water ,board1 p4 #hf1 #ahic4 ,bibliography #bc3 ,,forbes1 ,f4 ,b41 and ,,pratt1 ,g4 ,h4 ,the determination of carbonic acid in drinking water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #be1 pp4 #gdb-ef1 #aijc4 ,bibliography #bd3 ,,fowler1 ,g4 ,j4 ,sewage works analyses1 pp4 #ba-cg1 ,john ,wiley ,sons1 ,new ,york1 #aijb2 ,bibliography #bd;a3 pp4 #ca-d2 ,bibliography #bd;b3 pp4 #eh-fj2 ,bibliography #bd;c3 pp4 #hf-i2 ,bibliography #bd;d3 pp4 #hi-ie2 ,bibliography #bd;e3 pp4 #if-g2 ,bibliography #bd;f3 pp4 #ih-ajj4 ,bibliography #bf3 ,,fowler1 ,g4 ,j4 ,univ4 of ,manchester ,lecture1 ,march1 #aijd1 ,pamphlet1 p4 #g4 ,bibliography #bg3 ,,fox1 ,,charles ,j4 ,j4 ,on the coefficients of absorption of nitrogen and oxygen in distilled water and sea water and of atmospheric carbonic acid in sea water3 ,trans4 ,faraday ,soc41 ,vol4 #e1 pp4 #fh-hg1 #aiji4 ,bibliography #bi3 ----4 ,the composition of sewage in relation to problems of disposal3 ,tech4 ,quart41 ,vol4 #af1 pp4 #acb-afj1 #aijc4 ,bibliography #cj3 ----4 ,experiments upon the purification of sewage and water at the ,lawrence ,experiment ,station3 ,report ,mass4 ,state ,board of ,health1 pp4 #ddg-gjj1 #ahid4 ,bibliography #ca3 ,,haywood1 ,j4 ,k41 and ,,warner1 ,h4 ,j4 ,arsenic in papers and fabrics3 ,u4 ,s4 ,agri4 ,dept4 ,bur4 ,chem4 ,bull4 #hf1 pp4 #be-g1 #aijd4 ,bibliography #cb3 ,,gill1 ,a4 ,h4 ,on the determination of nitrates in potable water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #af1 pp4 #abb-cb1 #aic-g1 #ahid4 ,bibliography #cc3 ,,gooch1 ,f4 ,a4 ,a method for the separation and estimation of boric acid3 ,am4 ,chem4 ,j41 ,vol4 #i1 pp4 #bc-cc1 #ahhg4 ,bibliography #cd3 ----4 ,a method for the separation of sodium and potassium from lithium by the action of amyl alcohol on the chlorides3 ,am4 ,chem4 ,j41 ,vol4 #i1 pp4 #cc-ea1 #ahhg2 also ,u4 ,s4 ,geol4 ,survey ,bull4 #dbb1 p4 #age2 also ,u4 ,s4 ,agri4 ,dept4 ,bur4 ,chem41 ,bull4 #aeb1 p4 #hj1 #aiaa4 ,bibliography #ce3 ,,gottschalk1 ,v4 ,h41 and ,,roesler1 ,h4 ,a4 ,action of soap on calcium and magnesium solutions3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bf1 pp4 #hea-f1 #aijd4 ,bibliography #cf3 ,,grandval1 ,,al41 and ,,lajoux1 ,h4 ,nouveau procd pour la recherche et le dosage rapide de faibles quantits d' acide nitrique dans l'air1 l'eau1 le sol1 etc41 ,comptes rend41 ,vol4 #aja1 pp4 #fb-e1 #ahhe4 ,bibliography #cg3 ,,handy1 ,j4 ,o4 ,determination of acidity or alkalinity3 ,proc4 ,engineers ,soc4 ,west4 ,pa41 ,vol4 #ai1 p4 #gje1 #aijc4 ,bibliography #ch3 ,,harrington1 ,,charles1 and ,,richardson1 ,m4 ,w4 ,a manual of practical hygiene1 #eth ed41 pp4 #deg-fb1 ,lea ,febiger1 ,phila4 and ,new ,york1 #aiad4 ,bibliography #ci3 ,,hazen1 ,,allen4 ,on the determination of chlorine in water3 ,am4 ,chem4 ,j41 ,vol4 #aa1 pp4 #dji-ad1 #ahhi4 ,bibliography #dj3 ----4 ,apparatus for the determination of ammonias in sand sewage3 ,am4 ,chem4 ,j41 ,vol4 #ab1 pp4 #dbg-h1 #ahij4 ,bibliography #db3 ----4 ,report on the chemical precipitation of sewage3 ,examinations by the ,state ,board of ,health of water supplies of ,mass41 #ahhg-ij1 pt4 #b1 ,purification of water and sewage1 pp4 #gce-ia1 #ahij4 ,bibliography #dc3 ----4 ,a new color standard for natural waters3 ,am4 ,chem4 ,j41 ,vol4 #ad1 pp4 #cjj-aj1 #ahib4 ,bibliography #dd3 ----4 ,experiments on the purification of sewage at the ,lawrence ,experiment ,station3 ,report ,mass4 ,state ,board of ,health1 pp4 #cic-ddh1 #ahib4 ,bibliography #de3 ----1 and ,,clark1 ,h4 ,w4 ,on the effect of temperature upon the determination of ammonia by ,nesslerization3 ,am4 ,chem4 ,j41 ,vol4 #ab1 pp4 #dbe-f1 #ahij4 ,bibliography #df3 ----1 and ----4 ,on the determination of nitrates in water3 ,chem4 ,news1 ,vol4 #fd1 pp4 #afb-d1 #ahia4 ,bibliography #dg3 ,,hehner1 ,,otto4 ,estimation of hardness without soap solution3 ,analyst1 ,vol4 #h1 pp4 #gg-ha1 #ahhc4 ,bibliography #dh3 ,,hillebrand1 ,w4 ,f4 ,the analysis of silicate and carbonate rocks3 ,u4 ,s4 ,geol4 ,survey ,bull4 #dbb1 pp4 #aac-h1 #abg-h1 #ada-f1 #bai-bj1 #bba1 #bbb1 and #bcj1 #aiaj4 ,bibliography #di3 ,,hollis1 ,f4 ,s4 ,methods for the determination of color and the relation of the color to the character of the water3 ,j4 ,n4 ,e4 ,water ,works ,assoc41 ,vol4 #ac1 pp4 #id-aah1 #ahih4 ,bibliography #ej3 ,,howe1 ,,freeland1 ,,jr4 ,a new method for determining the color of the turbidity of water3 ,eng4 ,rec41 ,vol4 #ej1 pp4 #gbj-a1 #aijd4 ,bibliography #ea3 ,,ilosvay1 ,l4 ,l'acide azoteux dans la salive et dans l'air exhal3 ,bull4 de la ,socite ,chimique1 ser4 #c1 ,vol4 #b1 pp4 #chh-ia1 #ahhi4 ,bibliography #eb3 ,,jackson1 ,d4 ,d4 ,permanent standards for use in the analysis of water3 ,tech4 ,quart41 ,vol4 #ac1 pp4 #cad-bf1 #aijj4 ,bibliography #eb;a3 a4 ----1 and ,,horton1 ,w4 ,a4 ,experiments on the putrescibility test for sewage and sewage effluents3 ,j4 ,ind4 ,eng4 ,chem41 ,vol4 #a1 pp4 #cbh-cc1 #aiji4 ,bibliography #ec3 ----1 and ,,ellms1 ,j4 ,w4 ,on odors and tastes of surface waters1 with special reference to anabaena1 a microscopical organism found in certain water supplies of ,massachusetts3 ,tech4 ,quart41 ,vol4 #aj1 pp4 #daj-bj1 #ahig4 ,bibliography #ed3 ,,johnson1 ,g4 ,a4 ,report on sewage purification at ,columbus1 ,ohio1 made to the chief engineer of the ,board of ,public ,service1 p4 #dg1 #aije4 ,bibliography #ee3 ,,kendall1 ,l4 ,m41 and ,,richards1 ,e4 ,h4 ,permanent standards in water analysis3 ,tech4 ,quart41 ,vol4 #ag1 pp4 #bgg-hj1 #aijd4 ,bibliography #ef3 ,,kimberley1 ,a4 ,e41 and ,,hommon1 ,h4 ,b4 ,the practical advantages of the ,gooch crucible in the determination of the total and volatile suspended matter in sewage3 ,pub4 ,health ,papers and ,repts41 ,am4 ,pub4 ,health ,assoc41 ,vol4 #ca1 pt4 #b1 pp4 #abc-ce1 #aije4 ,bibliography #eg3 ,,kinnicutt1 ,l4 ,p4 ,quoted by ,gage1 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bg1 p4 #cci1 #aije4 ,bibliography #eh3 ,,kjeldahl1 ,j4 ,neue ,methode zur ,bestimmung des ,stickstoffs in organischen ,krpern3 ,z4 anal4 ,chem41 ,vol4 #bb1 pp4 #cff-hb1 #ahhc4 ,bibliography #ei3 ,,klut1 ,mitt4 a4 d4 ,knig4 ,prfungs1 ,vol4 #ab1 p4 #ahf4 ,bibliography #fj3 ,,leach1 ,a4 ,e4 ,food inspection and analysis1 pp4 #dic1 #die1 and #dig1 ,john ,wiley ,sons1 ,new ,york1 #aijd4 ,bibliography #fj;a3 a4 ,,lederer1 ,,arthur4 ,a new method for determining the relative stability of sewage1 effluent1 or polluted river water3 ,j4 ,infect4 ,diseases1 ,vol4 #ad1 pp4 #dhb-ig1 #aiad4 ,bibliography #fj;b3 b4 ----4 ,a serious fallacy of the 8standard0 methylene blue putrescibility test3 ,am4 ,j4 ,pub4 ,health1 ,vol4 #d 7old series ,vol4 #aj71 pp4 #bda-h1 #aiad4 ,bibliography #fj;c3 c4 ----4 ,notes on the practical application of the 8saltpeter method0 for determining the strength of sewages3 ,am4 ,j4 ,pub4 ,health1 ,vol4 #e1 pp4 #ced-fa1 #aiae4 ,bibliography #fj;d3 d4 ----4 ,determination of the biochemical oxygen demand by the saltpeter method in stockyards1 tannery1 and corn products wastes3 ,j4 ,ind4 ,eng4 ,chem41 ,vol4 #g1 pp4 #ead-f1 #aiae4 ,bibliography #fa3 ,,leeds1 ,a4 ,r4 ,estimation by titration of dissolved carbon dioxide in water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #ac1 pp4 #ih-i1 #ahia4 ,bibliography #fb3 ----4 ,the alteration of standard ammonium solutions when kept in the dark3 ,proc4 ,am4 ,chem4 ,soc41 ,vol4 #b1 p4 #a1 #ahgh4 ,bibliography #fc3 ,,leffman1 ,,henry4 ,examination of water1 #c;d ed41 pp4 #df-ej1 ,p4 ,blakiston's ,son ,co41 ,philadelphia1 #ahie2 ,bibliography #fc;a3 pp4 #dd-f2 ,bibliography #fc;b3 pp4 #eg-h4 ,bibliography #fd3 ----4 ,examination of water1 #gth ed41 pp4 #ce-g1 ,p4 ,blakiston's ,son ,co41 ,philadelphia1 #aiae2 ,bibliography #fd;a3 pp4 #fd-g4 ,bibliography #fe3 ,,levy1 ,d4 ,d4 ,ann4 de l',observatoire de ,mont-,souris1 #ahhc et seq4 ,bibliography #ff3 ,,lovibond1 ,j4 ,w4 ,a description of the tintometer with some remarks on its application to chemical analysis3 ,j4 ,soc4 ,chem4 ,ind41 ,vol4 #g1 pp4 #dbd-f1 #ahhh4 ,bibliography #fg3 ,,mallet1 ,j4 ,w4 ,water analysis3 ,annual ,report ,national ,board of ,health1 pp4 #ahi-ced1 #ahhb4 ,bibliography #fh3 ,,mason1 ,w4 ,p4 ,examination of water1 #dth ed41 pp4 #he-i1 ,john ,wiley ,sons1 ,new ,york1 #aiaj2 ,bibliography #fh;a3 pp4 #cc-da2 ,bibliography #fh;b3 pp4 #ei-gd2 ,bibliography #fh;c3 pp4 #ajf-i4 ,bibliography #fi3 ,,mcgowan1 ,,george4 ,kjeldahl process for the estimation of total nitrogen and 7indirectly7 of total organic nitrogen3 ,royal ,commission on ,sewage ,disposal1 ,vol4 #d1 pt4 #e1 pp4 #bd-ca1 #aijd2 ,bibliography #fi;a3 pp4 #cg-da2 ,bibliography #fi;b3 pp4 #dg-h4 ,bibliography #gj3 ,,palmer1 ,a4 ,w4 ,chemical survey of the waters of ,illinois1 ,report for years #ahig-aijb1 pp4 #bg-h1 ,univ4 ,ill41 #aijc4 ,bibliography #ga3 ----4 ,report of the ,university of ,illinois in ,report of streams examination1 ,sanitary ,dist4 ,chicago1 p4 #fj1 ,chicago1 #aijc2 ,bibliography #ga;a3 p4 #ef2 ,bibliography #ga;b3 pp4 #fa-d4 ,bibliography #gb3 ,,parker1 ,g4 ,h4 ,report of the biologist3 ,examinations by the ,state ,board of ,health of water supplies of ,mass41 #ahhg-ij1 pt4 #a1 ,examination of water supplies1 pp4 #ehc-g1 #ahij4 ,bibliography #gc3 ,,parmelee1 ,c4 ,l41 and ,,ellms1 ,j4 ,w4 ,on rapid methods for the estimation of the weight of suspended matters in turbid waters3 ,tech4 ,quart41 ,vol4 #ab1 pp4 #ade-fd1 #ahii4 ,bibliography #gd3 ,,pfeifer1 ,j41 and ,,wartha1 ,,prof4 ,kritische ,studien ber ,untersuchung und ,reinigung des ,kesselspeisewassers3 ,z4 angew4 ,chem41 ,vol4 #ae1 pp4 #aic-bjg1 #aijb4 ,bibliography #ge3 ,,phelps1 ,e4 ,b4 ,a critical study of the methods in current use for the determination of free and albuminoid ammonia in sewage1 ,public ,health ,papers and ,reports1 ,am4 ,pub4 ,health ,assoc41 ,vol4 #bi1 p4 #ced1 #aijd2 ,j4 ,infect4 ,dis41 ,vol4 #a1 p4 #cbg1 #aijd4 ,bibliography #gf3 ----4 ,the determination of the organic nitrogen in sewage by the ,kjeldahl process3 ,j4 ,infect4 ,dis41 ,supp4 #a1 pp4 #bee-gb1 #aije4 ,bibliography #gg3 ----4 ,the determination of small quantities of copper in water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bh1 pp4 #cfh-gb1 #aijf4 ,bibliography #gh3 ----4 ,putrescibility and stability of sewage effluents3 ,contrib4 ,sanit4 ,research ,lab41 ,mass4 ,inst4 ,tech41 ,vol4 #e1 p4 #hg1 #aiji2 also ,the disinfection of sewage and sewage filter effluents3 ,u4 ,s4 ,geol4 ,survey ,water-,supply ,paper #bbi1 pp4 #gd-hh1 #aiji4 ,bibliography #gi3 ,preface to report of committee on the pollution of water supplies3 ,public ,health ,papers and ,reports1 ,am4 ,pub4 ,health ,assoc41 ,vol4 #bc1 pp4 #ef-g1 #ahig4 ,report1 pp4 #eh-ajj4 ,bibliography #hj3 ,report of committee on standard methods of water analysis3 ,public ,health ,papers and ,reports1 ,am4 ,pub4 ,health ,assoc41 ,vol4 #bg1 pp4 #cgg-ia1 #aija4 ,bibliography #ha3 ,,proctor1 ,h4 ,r4 ,some recent methods of technical water analysis3 ,j4 ,soc4 ,chem4 ,ind41 ,vol4 #bc1 pp4 #h-aa1 #aijd4 ,bibliography #hb3 ----4 ,on a modified form of tintometer or colorimeter3 ,j4 ,soc4 ,chem4 ,ind41 ,vol4 #ad1 pp4 #abb-d1 #ahie4 ,bibliography #hc3 ,,richards1 ,e4 ,h41 and ,,ellms1 ,j4 ,w4 ,the coloring matter of natural waters1 its source1 composition1 and quantitative measurement3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #ah1 pp4 #fh-ha1 #ahif4 ,bibliography #hd3 ,,rideal1 ,,samuel4 ,sewage1 #b;d ed41 pp4 #ch-dj1 ,john ,wiley ,sons1 ,new ,york1 #aija2 ,bibliography #hd;a3 pp4 #ca-d4 ,bibliography #he3 ,royal ,commission on ,sewage ,disposal1 ,testimony1 ,vol4 #b1 pp4 #cbf-cg1 #aijb4 ,bibliography #hf3 ,,scholl1 ,,clarence4 ,the perchloric method of determining potassium as applied to water analysis3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #cf1 pp4 #bihe-i1 #aiad4 ,bibliography #hg3 ,,seyler1 ,c4 ,a4 ,notes on water analysis3 ,chem4 ,news1 ,vol4 #gj1 pp4 #hb-c1 #ajd-e1 #aab-d1 #adj-a1 #aea-b1 and #ahg1 #ahid4 ,bibliography #hh3 ----4 ,the estimation of carbonic acid in natural waters3 ,analyst1 ,vol4 #bb1 pp4 #cab-i1 #ahig4 ,bibliography #hi3 ,,smart1 ,,chas4 ,report of the committee on pollution of water supplies3 ,public ,health ,papers and ,reports1 ,am4 ,pub4 ,health ,assoc41 ,vol4 #bj1 pp4 #gb-hb1 #ahie2 ,bibliography #hi;a3 pp4 #dei-eaf4 ,bibliography #ij3 ,,sprengel1 ,,hermann4 ,ueber die ,erkennung der ,salpetersare3 ,ann4 ,physik und ,chemie1 ,vol4 #aba1 pp4 #ahh-ia1 #ahfd4 ,bibliography #ia3 ,standard methods of water analysis3 ,science1 new ser41 ,vol4 #ab1 pp4 #ijf-ae1 #aijj4 ,bibliography #ib3 ,,stearns1 ,f4 ,p41 and ,,drown1 ,t4 ,m4 ,discussion of special topics relating to the quality of public water supplies3 ,examinations by the ,state ,board of ,health of water supplies of ,mass41 #ahhg-ij1 pt4 #a1 ,examination of water supplies1 pp4 #gdj-i1 #ahij4 ,bibliography #ic3 ,,street1 ,j4 ,p4 ,report on nitrogen3 ,in ,proc4 ,assoc4 ,off4 ,agri4 ,chemists2 ,u4 ,s4 ,agri4 ,dept4 ,bur4 ,chem4 ,bull4 #di1 pp4 #ab-be1 #ahig4 ,bibliography #id3 ,,sutton1 ,,francis4 ,volumetric analysis1 #ajth ed41 pp4 #gb-d1 ,p4 ,blakiston's ,son ,co41 ,philadelphia1 #aiaa2 ,bibliography #id;a3 pp4 #ii-aja2 ,bibliography #id;b3 pp4 #bci and #dgg2 ,bibliography #id;c3 pp4 #dgj-a2 ,bibliography #id;d3 pp4 #dgi-hc2 ,bibliography #id;e3 p4 #dgc1 #dgi-hc2 ,bibliography #id;f3 pp4 #dhd-h4 ,bibliography #ie3 ,,tatlock1 ,r4 ,r41 and ,,thompson1 ,r4 ,t4 ,the analysis of waters and their changes in composition when employed in steam raising3 ,j4 ,soc4 ,chem4 ,ind41 ,vol4 #bc1 pp4 #dbh-ca1 #aijd4 ,bibliography #if3 ,,thomas1 ,g4 ,e41 and ,,hall1 ,c4 ,a4 ,new apparatus in water analysis3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bd1 pp4 #ece-i1 #aijb4 ,bibliography #ig3 ,,thomson1 ,r4 ,t4 ,use of litmus1 methyl orange1 phenacetolin1 and phenolphthalein as indicators3 ,chem4 ,news1 ,vol4 #dg1 pp4 #abc-g1 #ahhc4 ,bibliography #ih3 ,,thomson1 ,,andrew4 ,colorimetric method for determining small quantities of iron3 ,j4 ,chem4 ,soc41 ,vol4 #dg1 pp4 #dic-g1 #ahhe4 ,bibliography #ii3 ,,thresh1 ,j4 ,c4 ,a new method of estimating the oxygen dissolved in water3 ,j4 ,chem4 ,soc41 ,vol4 #eg1 pp4 #ahe-ie1 #ahij4 ,bibliography #ajj3 ----4 ,the examination of water and water supplies1 p4 #bjj1 ,philadelphia1 #aijd2 ,bibliography #ajj;a3 p4 #bai2 ,bibliography #ajj;b3 p4 #aie2 ,bibliography #ajj;c3 p4 #bhb4 ,bibliography #aja3 ,,tidy1 ,c4 ,m4 ,the process for determining the organic purity of potable waters3 ,j4 ,chem4 ,soc41 ,vol4 #ce1 pp4 #df-ajf1 #ahgi4 ,bibliography #ajb3 ,,tiemann1 ,,ferdinand1 and ,g,,rtner1 ,,august4 ,handbuch der ,wsser1 #dth ed41 pp4 #bee-h1 ,friedrich ,vieweg und ,sohn1 ,braunschweig1 #ahie4 ,bibliography #ajc3 ,,treadwell1 ,f4 ,p4 translated by ,hall1 ,w4 ,t41 ,analytical ,chemistry1 #c;d ed41 ,vol4 #b1 pp4 #fhg-fhh1 ,john ,wiley ,sons1 ,new ,york1 #aiaa2 ,bibliography #ajc;a3 pp4 #ej-c4 ,bibliography #ajd3 ,,trommsdorff1 ,,hugo4 ,bestimmung der ,organischen ,substanzen3 ,zeit4 ,anal4 ,chem41 ,vol4 #h1 p4 #cdd1 #ahfi4 ,bibliography #aje3 ,u4 ,s4 ,,geological ,,survey4 ,measurement of color and turbidity of water1 ,form #i-ahb1 ,washington1 #aijb4 ,bibliography #ajf3 ,,wanklyn1 ,j4 ,a4 ,verification of ,wanklyn1 ,chapman1 and ,smith's water analyses on a series of artificial waters3 ,j4 ,chem4 ,soc41 ,vol4 #bj1 pp4 #eia-e1 #ahfg4 ,bibliography #ajg3 ----4 ,water analysis1 #ajth ed41 pp4 #cc-e1 ,kegan1 ,paul1 ,trench1 ,trbner1 ,co41 ,ltd41 ,london1 #ahif2 ,bibliography #ajg;a3 pp4 #ajf-g4 ,bibliography #ajh3 ,,warington1 ,,robert4 ,note on the appearance of nitrous acid during evaporation of water3 ,j4 ,chem4 ,soc41 ,vol4 #ci1 pp4 #bbi-cd1 #ahha4 ,bibliography #aji3 ,,warren1 ,h4 ,e41 and ,,whipple1 ,g4 ,c4 ,the thermophone1 a new instrument for determining temperatures3 ,tech4 ,quart41 ,vol4 #h1 pp4 #abe-eb1 #ahie4 ,bibliography #aaj3 ,,west1 ,f4 ,d4 ,the preparation of standards for the determination of turbidity of water3 ,proc4 ,ill4 ,water ,supply ,assoc41 ,vol4 #f1 pp4 #di-ea1 #aiad4 ,bibliography #aaa3 ,,weston1 ,r4 ,s4 ,apparatus for the determination of ammonia in water by the ,wanklyn method1 and total nitrogen by the ,kjeldahl method3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bb1 pp4 #dfh-gc1 #aijj4 ,bibliography #aab3 ----4 ,the determination of nitrogen as nitrites in waters3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bg1 pp4 #bha-g1 #aije4 ,bibliography #aac3 ----4 ,the determination of manganese in water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #bi1 pp4 #ajgd-h1 #aijg4 ,bibliography #aad3 ,,whipple1 ,g4 ,c4 ,the observation of odor as an essential part of water analysis3 ,public ,health ,papers and ,reports1 ,am4 ,pub4 ,health ,assoc41 ,vol4 #be1 pp4 #ehg-ic1 #ahii4 ,bibliography #aae3 ----4 ,the microscopy of drinking water1 #c;d ed41 pp4 #ahf-bje1 ,john ,wiley ,sons1 ,new ,york1 #aiad4 ,bibliography #aaf3 ----1 and ,,jackson1 ,d4 ,d4 ,a comparative study of the methods used for the measurement of the turbidity of water3 ,tech4 ,quart41 ,vol4 #ac1 pp4 #bgd-id1 #aijj4 ,bibliography #aag3 ----1 and others4 ,the decolorization of water3 ,trans4 ,am4 ,soc4 ,civil ,eng41 ,vol4 #df1 pp4 #ada-ha1 #aija4 ,bibliography #aah3 ----1 and ,,parker1 ,h4 ,n4 ,on the amount of oxygen and carbonic acid dissolved in natural waters and the effect of these gases upon the occurrence of microscopic organisms3 ,trans4 ,am4 ,microscopical ,soc41 ,vol4 #bc1 pp4 #ajc-dd1 #aija4 ,bibliography #aai3 ----1 and ,,whipple1 ,m4 ,c4 ,solubility of oxygen in sea water3 ,j4 ,am4 ,chem4 ,soc41 ,vol4 #cc1 pp4 #cfb-e1 #aiaa4 ,bibliography #abj3 ,,winkler1 ,l4 ,w4 ,die ,bestimmung des im ,wasser gelsten ,sauerstoffes3 ,ber41 pp4 #bhdc-ed1 #ahhh4 ,bibliography #aba3 ,,woodman1 ,a4 ,g41 and ,,norton1 ,j4 ,f4 ,air1 water1 and food1 #dth ed41 pp4 #gb-h1 ,john ,wiley ,sons1 ,new ,york1 #aiad2 ,bibliography #aba;a3 pp4 #he-g2 ,bibliography #aba;b3 pp4 #ij-a1 #baf1 and #bca2 ,bibliography #aba;c3 pp4 #ajf-h4 ,,microscopical ,,examination4 ,the microscopical examination of water consists of the enumeration of the kinds of microscopic organisms 7,plankton71 and an estimation of their quantity4 ,it may serve any one or more of the following purposes3 7#a7 ,to explain the presence of objectionable odors and tastes4 7#b7 ,to indicate the progress of the self purification of streams4 7#c7 ,to indicate the presence of sewage contamination4 7#d7 ,to explain the chemical analysis4 7#e7 ,to identify the source of a water4 7#f7 ,to aid in the study of the food of fish1 shellfish1 and other aquatic organisms4 ,the term 8,microscopic ,organisms0 shall include all organisms microscopic or barely visible to the naked eye1 with the exception of the bacteria4 ,it includes the diatomaceae1 chlorophyceae1 cyanophyceae1 fungi1 protozoa1 rotifera1 crustacea1 bryophyta1 and spongidae found in water4 ,fragments of organic matter1 silt1 mineral matter1 zoglea1 etc41 shall be considered as amorphous matter4 ,the recording of amorphous matter usually serves no useful purpose and shall not be considered a part of the standard method4 ,apparatus4--#a4 ,a cylindrical funnel about two inches in diameter at the top1 with a straight side for nine inches1 narrowed over a distance of three inches to a bore of one-half inch in diameter1 and terminating in a straight portion of this diameter two and one-half inches in length4 ,the capacity of this funnel is #ejj cc4 ,it shall be provided at the bottom with a tightly fitting rubber stopper with a single perforation and a disk of silk bolting cloth over the hole about three eighths of an inch in diameter4 #b4 ,a counting cell consisting of a brass rim closely cemented to a plate of optical glass4 ,the shape and size of this cell are not essential but its depth shall be one millimeter4 ,a convenient capacity is about one cubic centimeter4 #c4 ,an ocular micrometer ruled as follows3 ,the ocular micrometer is commonly of such a size that with a #af mm4 objective and a suitable tube length1 the largest square cuts off one square millimeter on the stage4 ,procedure4--,filter #bej cc4 of the water 7more or less according to the clearness of the sample7 through a one-half inch layer of quartz sand 7washed and screened between #fj and #abj mesh sieves7 supported by the disk of bolting cloth and rubber stopper at the bottom of the funnel4 ,suction may be applied to hasten the filtration4 ,remove the stopper and catch the plug of sand and its entrained organisms in a small beaker or test tube1 washing down the inside of the funnel into the beaker with #e cc4 of clean 7preferably distilled7 water4 ,agitate the mixture of sand1 water1 and organisms to detach the latter from the sand grains1 and quickly decant the water and the organisms in suspension to a test tube4 ,if desired the sand may then be again washed with #e cc4 water and the wash water added to the first portion4 ,cover the cell partially with a cover glass1 and by means of a pipette run the concentrate under the cover glass until the cell is completely filled4 ,cover and place on the microscope stage in a horizontal position for examination4 ,count the organisms in twenty fields1 i4 e41 twenty cubic millimeters1 estimating their areas in terms of ,standard ,units4 ,the ,standard ,unit is the smallest square in the ocular micrometer1 and represents an area #bj #bj1 or #djj square microns on the stage4 ,results shall be expressed in the number of ,standard ,units of each kind of micro-organism per cc4 and also the total number of standard units of all kinds per cc4 ,the general directions as to significant figures given under ,turbidity shall apply also to the microscopical examination4 ,caution4--,many micro-organisms1 especially some of those causing odors1 are so fragile that they are broken up in filtration1 especially if the agitation of the filtrate is too vigorous4 ,a direct examination of a fresh sample is therefore a useful supplementary procedure4 ,for the same reason the concentrate should not stand long before examination4 ,also some organisms are carried by specific gravity to the top of the cell which should be scrutinized as well as the bottom layer each time4 ,it is always better to examine the micro-organisms in the field when possible1 and for this purpose the sling filter has been devised consisting of a metal funnel slung to a pivoted handle1 with a disk of wire gauze in the detachable lower end to support the sand4 ,filtration is hastened by imparting a whirling motion to the whole and utilizing the centrifugal force thus generated4 ,illustration3 ,,the ,,ocular ,,micrometer4 ,,microscopical ,,bibliography4 a4 ,,kean1 ,a4 ,l4 ,a new method for the microscopical examination of water3 ,science1 ,vol4 #ac1 p4 #acb1 #ahhi2 ,eng4 ,news1 pp4 #ba1 #bgf1 #ahhi4 b4 ,,sedgwick1 ,w4 ,t4 ,recent progress in biological water analysis3 ,j4 ,n4 ,e4 ,water ,works ,assoc41 ,vol4 #d1 pp4 #ej-fd1 #ahhi4 c4 ----4 ,a report of the biological work of the ,lawrence ,experiment ,station3 ,examinations by the ,state ,board of ,health of water supplies of ,mass41 #ahhg-ij1 pt4 #b1 ,purification of sewage and water1 pp4 #gic-hfb1 #ahij4 d4 ,,parker1 ,g4 ,h4 ,report upon the organisms1 excepting the bacteria found in the waters of the ,state3 ,examinations by the ,state ,board of ,health of water supplies of ,mass41 #ahhg-ij1 pt4 #a1 ,examination of water supplies1 pp4 #egi-fbj1 #ahij4 e4 ,,rafter1 ,g4 ,w4 ,the microscopical examination of potable water1 ,d4 ,van ,nostrand ,co41 ,new ,york1 #aiaj4 7,contains bibliography47 f4 ,,calkins1 ,g4 ,n4 ,the microscopical examination of water3 ,report ,mass4 ,state ,board of ,health1 pp4 #cig-dba1 #ahib4 g4 ,,jackson1 ,d4 ,d4 ,on an improvement in the ,sedgwick-,rafter method for the microscopical examination of drinking water3 ,tech4 ,quart41 ,vol4 #i1 pp4 #bga-d1 #ahif4 h4 ,,whipple1 ,g4 ,c4 ,experience with the ,sedgwick-,rafter method at the ,biological ,laboratory of the ,boston ,water ,works3 ,tech4 ,quart41 ,vol4 #i1 pp4 #bge-i1 #ahif4 i4 ----4 ,microscopy of drinking water1 #c;d ed41 ,john ,wiley ,sons1 ,new ,york1 #aiad4 7,contains bibliography47 ,,bacteriological ,,examination4 ,i4 ,,apparatus4 #a4 ,sample ,bottles4--,any size1 shape or quality of bottle may be used for a bacterial sample1 provided it holds a sufficient amount to carry out all the tests required and is such that it may be properly washed and sterilized and will keep the sample uncontaminated until the analysis is made4 ,four- or eight-ounce1 ground-glass-stoppered bottles are recommended4 ,these should be protected by being wrapped in paper1 or their necks covered with tin foil1 and should be placed in proper boxes for transportation4 #b4 ,pipettes4--,pipettes may be of any convenient size or shape provided it is found by actual test that they deliver accurately the required amount in the manner in which they are used4 ,the error of calibration shall in no case exceed #b per cent4 ,protecting the pipettes with a cotton stopper is recommended4 #c4 ,dilution ,bottles4--,bottles for use in making dilutions should preferably be of tall form1 of such capacity as to hold at least twice the volume of water actually used4 ,close-fitting ground-glass stoppers are preferable1 but tight fitting cotton stoppers may be used1 provided due care is taken to prevent contamination and to avoid loss of volume through wetting of the stopper before mixing has been accomplished4 #d4 ,petri ,dishes4--,petri dishes ten centimeters in diameter shall be used with glass or porous tops#baa as preferred4 ,the bottoms of the dishes shall be as flat as possible so that the medium shall be of uniform thickness throughout the plate4 #e4 ,fermentation ,tubes4--,any type of fermentation tube#bjc may be used provided it holds at least three times as much medium as the amount of water to be tested4 ,,ii4 ,,materials4 #a4 ,water4--,distilled water shall be used in the preparation of all culture media and reagents4 #b4 ,meat ,extract4--,liebig's meat extract shall be used in place of meat infusion4 ,other brands may be substituted for ,liebig's when comparative tests have shown that they give equivalent results4 #c4 ,peptone4--,armour's1 ,digestive ,ferments ,company's1 ,fairchild's1 or any other peptone which gives equivalent results may be used4 #d4 ,sugars4--,all sugars used shall be of the highest purity obtainable4 #e4 ,agar4--,the agar used shall be of the best quality and shall be dried for one-half hour at #aje ,c4 before weighing4 ,much of the agar on the market contains considerable amounts of sea salts4#bbabbebbh ,these may be removed by soaking in water and draining before use4 #f4 ,gelatin4--,the gelatin used shall be of light color1 shall contain not more than a trace of arsenic1 copper1 sulfides1 and shall be free from preservatives1 and of such a melting point that a #aj per cent4 standard nutrient gelatin shall have a melting point of #be ,c4 or over4 ,gelatin shall be dried for one-half hour at #aje ,c4 before weighing4 #g4 ,litmus4--,reagent litmus of highest purity 7not litmus cubes7 or azolitmin 7,kahlbaum7 shall be used for all media requiring a litmus indicator4 #h4 ,general ,chemicals4--,special effort shall be made to have all the other ingredients used for culture media chemically pure4 ,,iii4 ,,methods4 #a4 ,,preparation ,,of ,,culture ,,media4 a4 ,adjustment of ,reaction4 aa4 ,phenol ,red ,method for adjustment to a hydrogen-ion concentration of ,p,h #f4h-h4d4 ,withdraw #e cc4 of the medium1 dilute with #e cc4 of distilled water1 and add #e drops of a solution of phenol red 7phenol sulphone phthalein74 ,this solution is made by dissolving #j4jd grams of phenol red in #cj cc4 of alcohol and diluting to #ajj cc4 with distilled water4 ,titrate with a #a3aj dilution of a standard solution of ,na,o,h 7which need not be of known normality7 until the phenol red shows a slight but distinct pink color4 ,calculate the amount of the standard ,na,o,h solution which must be added to the medium to reach this reaction4 ,after the addition check the reaction by adding #e drops of phenol red to #e cc4 of the medium and #e cc4 of water4 bb4 ,titration with phenolphthalein4 7,for the convenience of those who wish to retain the use of this method for the present it is given here1 but it is recommended that as soon as possible the more accurate method of determining the hydrogen-ion concentration be substituted47 ,in a white porcelain dish put #e cc4 of the medium to be tested1 add #de cc4 of distilled water4 ,boil briskly for one minute4 ,add #a cc4 of phenolphthalein solution 7#e grams of commercial salt to one liter of #ej per cent4 alcohol74 ,titrate immediately with a n_/#bj solution of sodium hydrate4 ,a faint but distinct pink color marks the true end-point4 ,this color may be precisely described as a combination of #be per cent4 of red 7wave length approximately #feh7 with #ge per cent4 of white as shown by the disks of the standard color top made by the ,milton ,bradley ,educational ,co41 ,springfield1 ,mass4 ,all reactions shall be expressed with reference to the phenolphthalein neutral point and shall be stated in percentages of normal acid or alkali solutions required to neutralize them4 ,alkaline media shall be recorded with a minus 7-7 sign before the percentage of normal acid needed for their neutralization and acid media with a plus 77 sign before the percentage of normal alkali solution needed for their neutralization4 ,the standard reaction for culture media for water analysis shall be #a4j per cent41 as determined by tests of the sterilized medium4 ,as ordinarily prepared1 broth and agar will be found to have a reaction between #j4e and #a4j4 ,for such media no adjustment shall be made4 ,the reaction of media containing sugar shall be neutral to phenolphthalein4 ,whenever reactions other than the standard are used1 it shall be so stated4 b4 ,sterilization4 ,all media and dilution water shall be sterilized in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 ,all air must be forced out of the autoclav before the pressure is allowed to rise4 ,as soon as possible after sterilization the media shall be removed from the autoclav and cooled rapidly4 ,rapid and immediate cooling of gelatin is imperative4 ,media shall be sterilized in small containers1 and these must not be closely packed together4 ,no part of the medium shall be more than #b4e cm4 from the outside surface of the glass4 ,all glassware shall be sterilized in the dry oven at #agj ,c4 for at least #a hours4 c4 ,nutrient ,broth4 ,to ,make ,one ,liter4 #a4 ,add #c grams of beef extract and #e grams of peptone to #a1jjj cc4 of distilled water4 #b4 ,heat slowly on a steam bath to at least #fe ,c4 #c4 ,make up lost weight and adjust the reaction to a faint pink with phenol red1 or if the phenolphthalein titration is used1 and the reaction is not already between #j4e and #a1 adjust to #a4 #d4 ,cool to #be ,c4 and filter through filter paper until clear4 #e4 ,distribute in test-tubes1 #aj cc4 to each tube4 #f4 ,sterilize in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 d4 ,sugar ,broths4 ,sugar broths shall be prepared in the same general manner as nutrient broth with the addition of #j4e per cent4 of the required carbohydrate just before sterilization4 ,the removal of muscle sugar is unnecessary as the beef extract and peptone are free from any fermentable carbohydrates4 ,the reaction of sugar broths shall be a faint pink with phenol red or1 if on titration with phenolphthalein the reaction is not already between neutral and #a1 adjust to neutral4 ,sterilization shall be in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs41 provided the total time of exposure to heat is not more than one-half hour2 otherwise a #aj per cent4 solution of the required carbohydrate shall be made in distilled water and sterilized at #ajj ,c4 for #a hours1 and this solution shall be added to sterile nutrient broth in amounts sufficient to make a #j4e per cent4 solution of the carbohydrate and the mixture shall then be tubed and sterilized at #ajj ,c4 for #cj minutes1 or it is permissible to add by means of a sterile pipette directly to a tube of sterile neutral broth enough of the carbohydrate to make the required #j4e per cent4 ,the tubes so made shall be incubated at #cg ,c4 for #bd hours as a test for sterility4 e4 ,nutrient ,gelatin4 ,to ,make ,one ,liter4 #a4 ,add #c grams of beef extract and #e grams of peptone to #a1jjj cc4 of distilled water and add #ajj grams of gelatin dried for one-half hour at #aje ,c4 before weighing4 #b4 ,heat slowly on a steam bath to #fe ,c4 until all gelatin is dissolved4,g ,footnote ,g3 ,the solution of the gelatin will be facilitated by allowing it to soak in the cold one-half hour before heating4 #c4 ,make up lost weight and adjust the reaction to a faint pink with phenol red1 or if the phenolphthalein titration is used1 and the reaction is not already between #j4e and #a1 adjust to #a4 #d4 ,filter through cloth and cotton until clear4 #e4 ,distribute in test-tubes1 #aj cc4 to each tube1 or in larger containers as desired4 #f4 ,sterilize in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 f4 ,nutrient ,agar4 ,to ,make ,one ,liter4 #a4 ,add #c grams of beef extract1 #e grams of peptone and #ab grams of agar1 dried for one-half hour at #aje ,c4 before weighing1 to #a1jjj cc4 of distilled water4 ,boil over a water bath until all agar is dissolved1 and then make up the loss by evaporation4 #b4 ,cool to #de ,c4 in a cold water bath1 then warm to #fe ,c4 in the same bath1 without stirring4 #c4 ,make up lost weight and adjust the reaction to a faint pink with phenol red1 or if the phenolphthalein titration is used1 and the reaction is not already between #j4e and #a1 adjust to #a4 #d4 ,filter through cloth and cotton until clear4 #e4 ,distribute in test-tubes1 #aj cc4 to each tube1 or in larger containers1 as desired4 #f4 ,sterilize in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 g4 ,litmus or ,azolitmin ,solution4 ,the standard litmus solution shall be a #b per cent4 aqueous solution of reagent litmus4 ,powder the litmus1 add to the water and boil for five minutes4 ,the solution usually needs no correction in reaction and may be at once distributed in flasks or test-tubes and sterilized as is culture media4 ,it should give a distinctly blue plate when #a cc4 is added to #aj cc4 of neutral culture medium in a ,petri dish4 ,the standard azolitmin solution shall be a #a per cent4 solution of ,kahlbaum's azolitmin4 ,add the azolitmin powder to the water and boil for five minutes4 ,the solution may need to be corrected in reaction by the addition of sodium hydrate solution so that it will be approximately neutral and will give a distinctly blue plate when #a cc4 is added to #aj cc4 of neutral culture medium in a ,petri dish4 ,it may be distributed in flasks or test-tubes and sterilized as is culture media4 h4 ,litmus-lactose-agar4 ,litmus-lactose-agar shall be prepared in the same manner as nutrient agar with the addition of #a per cent4 of lactose just before sterilization4 ,the reaction shall be a faint pink with phenol red1 or1 if on titration with phenolphthalein the reaction is not already between neutral and #a1 adjust to neutral4 ,one cc4 of sterilized litmus or azolitmin solution shall be added to each #aj cc4 of the medium just before it is poured into the ,petri dish1 or the mixture may be made in the dish itself4 i4 ,endo's ,medium4#bjibadbae ,to ,make ,one ,liter4 #a4 ,add #e grams of beef extract1 #aj grams of peptone and #cj grams of agar dried for one-half hour at #aje ,c4 before weighing1 to #a1jjj cc4 of distilled water4 ,boil on a water bath until all the agar is dissolved and then make up the loss by evaporation4 #b4 ,cool the mixture to #de ,c4 in a cold water bath1 then warm to #fe ,c4 in the same bath without stirring4 #c4 ,make up lost weight1 titrate1 and if the reaction is not already between neutral and #a adjust to neutral4 #d4 ,filter through cloth and cotton until clear4 #e4 ,distribute #ajj cc4 or larger known quantities in flasks large enough to hold the other ingredients which are to be added later4 #f4 ,sterilize in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 #g4 ,prepare a #aj per cent4 solution of basic fuchsin in #ie per cent4 alcohol1 allow to stand #bj hours1 decant and filter the supernatant fluid4 ,this is a stock solution4 #h4 ,when ready to make plates melt #ajj cc4 of agar in streaming steam or on a water bath4 ,dissolve #a gram of lactose in #ae cc4 of distilled water1 using heat if necessary4 ,dissolve #j4be gram anhydrous sodium sulphite in #aj cc4 water4 ,to the sulphite solution add #j4e cc4 of the fuchsin stock solution4 ,add the fuchsin-sulphite solution to the lactose solution and then add the resulting solution to the melted agar4 ,the lactose used must be chemically pure and the sulphite solution must be made up fresh4 #i4 ,pour plates and allow to harden thoroughly in the incubator before use4 #b4 ,,collection ,,of ,,sample4 ,samples for bacterial analysis shall be collected in bottles which have been cleansed with great care1 rinsed in clean water1 and sterilized with dry heat for at least one hour and a half at #agj ,c41 or in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes or longer after the pressure reaches #ae lbs4 ,great care must be exercised to have the samples representative of the water to be tested and to see that no contamination occurs at the time of filling the sample bottles4 #c4 ,,storage ,,and ,,transportation ,,of ,,samples4 ,because of the rapid and often extensive changes which may take place in the bacterial flora of bottled samples when stored even at temperatures as low as #aj ,c41 it is urged1 as of importance1 that all samples be examined as promptly as possible after collection4 ,the time allowed for storage or transportation of a bacterial sample between the filling of the sample bottle and the beginning of the analysis should be not more than six hours for impure waters and not more than twelve hours for relatively pure waters4 ,during the period of storage1 the temperature shall be kept as near #aj ,c4 as possible4 ,any deviation from the above limits shall be so stated in making reports4 #d4 ,,dilutions4 ,dilution bottles shall be filled with the proper amount of tap water so that after sterilization they shall contain exactly #i cc4 or #ii cc4 as desired4 ,the exact amount of water can only be determined by experiment with the particular autoclav in use4 ,if desired1 the #i cc4 dilution may be measured out from a flask of sterile water with a sterile pipette4 ,dilution bottles shall be sterilized in the autoclav at #ae lbs4 7#abj ,c47 for #ae minutes after the pressure reaches #ae lbs4 ,the sample bottle shall be shaken vigorously #be times and #a cc4 withdrawn and added to the proper dilution bottles as required4 ,each dilution bottle after the addition of the #a cc4 of the sample1 shall be shaken vigorously #be times before a second dilution is made from it or before a sample is removed for plating4 #e4 ,,plating4 ,all sample and dilution bottles shall be shaken vigorously #be times before samples are removed for plating4 ,plating shall be done immediately after the dilutions are made4 ,one cc4 of the sample or dilution shall be used for plating and shall be placed in the ,petri dish1 first4 ,ten cc4 of liquefied medium at a temperature of #dj ,c4 shall be added to the #a cc4 of water in the ,petri dish4 ,the cover of the ,petri dish shall be lifted just enough for the introduction of the pipette or culture medium1 and the lips of all test-tubes or flasks used for pouring the medium shall be flamed4 ,in making litmus-lactose-agar plates1 #a cc4 of sterile litmus or azolitmin solution shall be added to each #aj cc4 of culture medium either in the ,petri dish or before pouring into the ,petri dish4 ,the medium and sample in the ,petri dish shall be thoroughly mixed and uniformly spread over the bottom of the ,petri dish by tilting or rotating the dish4 ,all plates shall be solidified as rapidly as possible after pouring and gelatin plates shall be placed immediately in the #bj ,c4 incubator and the agar plates in the #cg ,c4 incubator4 ,endo plates shall be made by placing one loopful of the material to be tested on the surface of the plate and distributing the material with a sterile loop or glass rod4 #f4 ,,incubation4 ,all gelatin plates shall be incubated for #dh hours at #bj ,c4 in a dark1 well-ventilated incubator in an atmosphere practically saturated with moisture4#bbg ,all agar plates shall be incubated for #bd hours at #cg ,c4 in a dark1 well-ventilated incubator in an atmosphere practically saturated with moisture4 ,glass covered plates shall be inverted in the incubator4 ,any deviation from the above described method shall be stated in making reports4 #g4 ,,counting4 ,in preparing plates1 such amounts of the water under examination shall be planted as will give from #be to #bej colonies on a plate2#bjb and the aim should be always to have at least two plates giving colonies between these limits4 ,where it is possible to obtain plates showing colonies within these limits1 only such plates should be considered in recording results1 except where the same amount of water has been planted in two or more plates1 of which one gives colonies within these limits1 while the others give less than #be or more than #bej4 ,in such case1 the result recorded should be the average of all the plates planted with this amount of water4 ,ordinarily it is not desirable to plant more than #a cc4 of water in a plate2 therefore1 when the total number of colonies developing from #a cc4 is less than #be1 it is obviously necessary to record the results as observed1 disregarding the general rule given above4 ,counting shall in all cases be done with a lens of #b diameter's magnification1 #c,x4 ,the ,engraver's ,lens ,no4 #adf made by the ,bausch ,lomb ,optical ,company fills the requirements1 and is a convenient lens for the purpose4 #h4 ,,the ,,test ,,for ,,the ,,presence ,,of ,,members ,,of ,,the ,b4 ,,coli ,,group4 ,it is recommended that the ,b4 coli group be considered as including all non-spore-forming bacilli which ferment lactose with gas formation and grow arobically on standard solid media4 ,the formation of #aj per cent4 or more of gas in a standard lactose broth fermentation tube within #bd hours at #cg ,c4 is presumptive evidence of the presence of members of the ,b4 coli group1 since the majority of the bacteria which give such a reaction belong to this group4 ,the appearance of arobic lactose-splitting colonies on lactose-litmus-agar or ,endo's medium plates made from a lactose broth fermentation tube in which gas has formed confirms to a considerable extent the presumption that gas-formation in the fermentation tube was due to the presence of members of the ,b4 coli group4 ,to complete the demonstration of the presence of ,b4 coli as above defined1 it is necessary to show that one or more of these arobic plate colonies consists of non-spore-forming bacilli which1 when inoculated into a lactose broth fermentation tube1 form gas4 ,it is recommended that the standard tests for the ,b4 coli group be either 7,a7 the ,presumptive1 7,b7 the ,partially ,confirmed1 or 7,c7 the ,completed test as hereafter defined1 each test being applicable under the circumstances specified4 ,a4 ,,presumptive ,,test4 #a4 ,inoculate a series of fermentation tubes with appropriate graduated quantities of the water to be tested4 ,in every fermentation tube there must always be at least three times as much medium as the amount of water to be tested4 ,when necessary to examine larger amounts than #aj cc4 as many tubes as necessary shall be inoculated with #aj cc4 each4 #b4 ,incubate these tubes at #cg ,c4 for #dh hours4 ,examine each tube at #bd and #dh hours1 and record gas-formation4 ,the records should be such as to distinguish between3 7a7 ,absence of gas-formation4 7b7 ,formation of gas occupying less than ten per cent4 7#aj7 of the closed arm4 7c7 ,formation of gas occupying more than ten per cent4 7#aj7 of the closed arm4 ,more detailed records of the amount of gas formed1 though desirable for purposes of study1 are not necessary for carrying out the standard tests prescribed4 #c4 ,the formation within #bd hours of gas occupying more than ten per cent4 7#aj7 of the closed arm of fermentation tube constitutes a positive presumptive test4 #d4 ,if no gas is formed in #bd hours1 or if the gas formed is less than ten per cent4 7#aj71 the incubation shall be continued to #dh hours4 ,the presence of gas in any amount in such a tube at #dh hours constitutes a doubtful test1 which in all cases requires confirmation4 #e4 ,the absence of gas formation after #dh hours' incubation constitutes a negative test4 7,an arbitrary limit of #dh hours' observation doubtless excludes from consideration occasional members of the ,b4 coli group which form gas very slowly1 but for the purposes of a standard test the exclusion of these occasional slow gas-forming organisms is considered immaterial47 ,b4 ,,partially ,,confirmed ,,test4 #a4 ,make one or more ,endo's medium or lactose-litmus-agar plates from the tube which1 after #dh hours' incubation1 shows gas formation from the smallest amount of water tested4 7,for example1 if the water has been tested in amounts of #aj cc41 #a cc41 and #j4a cc41 and gas is formed in #aj cc41 and #a cc41 not in #j4a cc41 the test need be confirmed only in the #a cc4 amount47 #b4 ,incubate the plates at #cg ,c41 #ah to #bd hours4 #c4 ,if typical colon-like red colonies have developed upon the plate within this period1 the confirmed test may be considered positive4 #d4 ,if1 however1 no typical colonies have developed within #bd hours1 the test cannot yet be considered definitely negative1 since it not infrequently happens that members of the ,b4 coli group fail to form typical colonies on ,endo's medium or lactose-litmus-agar plates1 or that the colonies develop slowly4 ,in such case1 it is always necessary to complete the test as directed under 8,c0 #b and #c4 ,c4 ,,completed ,,test4 #a4 ,from the ,endo's medium or lactose-litmus-agar plate made as prescribed under 8,b10 fish at least two typical colonies1 transferring each to an agar slant and a lactose broth fermentation tube4 #b4 ,if no typical colonies appear upon the plate within #bd hours1 the plate should be reincubated another #bd hours1 after which at least two of the colonies considered to be most likely ,b4 coli1 whether typical or not1 shall be transferred to agar slants and lactose broth fermentation tubes4 #c4 ,the lactose broth fermentation tubes thus inoculated shall be incubated until gas formation is noted2 the incubation not to exceed #dh hours4 ,the agar slants shall be incubated at #cg ,c4 for #dh hours1 when a microscopic examination shall be made of at least one culture1 selecting one which corresponds to one of the lactose broth fermentation tubes which has shown gas-formation4 ,the formation of gas in lactose broth and the demonstration of non-spore-forming bacilli in the agar culture shall be considered a satisfactory completed test1 demonstrating the presence of a member of the ,b4 coli group4 ,the absence of gas-formation in lactose broth or failure to demonstrate non-spore-forming bacilli in a gas-forming culture constitutes a negative test4 ,,application ,,of ,,presumptive1 ,,partially ,,confirmed1 ,,and ,,completed ,,tests4 ,a4 ,the ,presumptive ,test4 #a4 ,when definitely positive1 that is showing more than #aj per cent4 7#aj7 of gas in #bd hours1 is sufficient3 7a7 ,as applied to all except the smallest gas-forming portion of each sample in all examinations4 7b7 ,as applied to the smallest gas-forming portion in the examination of sewage or of water showing relatively high pollution1 such that its fitness for use as drinking water does not come into consideration4 ,this applies to the routine examinations of raw water in connection with control of the operation of purification plants4 #b4 ,when definitely negative1 that is showing no gas in #dh hours1 is final and therefore sufficient in all cases4 #c4 ,when doubtful1 that is showing gas less than #aj per cent4 7#aj7 7or none7 in #bd hours1 with gas either more or less than #aj per cent4 in #dh hours1 must always be confirmed4 ,b4 ,the ,partially ,confirmed ,test4 #a4 ,when definitely positive1 that is1 showing typical plate colonies within #bd hours1 is sufficient3 7a7 ,when applied to confirm a doubtful presumptive test in cases where the latter1 if definitely positive1 would have been sufficient4 7b7 ,in the routine examination of water supplies where a sufficient number of prior examinations have established a satisfactory index of the accuracy and significance of this test in terms of the completed test4 #b4 ,when doubtful1 that is1 showing colonies of doubtful or negative appearance in #bd hours1 must always be completed4 ,c4 ,the ,completed ,test4 ,the completed test is required as applied to the smallest gas-forming portion of each sample in all cases other than those noted as exceptions under the 8presumptive0 and the 8partially confirmed0 tests4 ,the completed test is required in all cases where the result of the confirmed test has been doubtful4 #i4 ,,expression ,,of ,,results4 ,in order to avoid fictitious accuracy and yet to express the numerical results by a method consistent with the precision of the work1 the numbers of colonies of bacteria per cubic centimeter shall be recorded as follows3#bab ,number of bacteria per cc4 ,from #a to #ej shall be recorded as found #ea #ajj to the nearest #e #aja #bej #aj #bea #ejj #be #eja #a1jjj #ej #a1jja #aj1jjj #ajj #aj1jja #ej1jjj #ejj #ej1jja #ajj1jjj #a1jjj #ajj1jja #ejj1jjj #aj1jjj #ejj1jja #a1jjj1jjj #ej1jjj #a1jjj1jja #aj1jjj1jjj #ajj1jjj ,this applies to the gelatin count at #bj ,c4 and to the agar count at #cg ,c4 ,,summary ,,of ,,steps ,,involved ,,in ,,making ,,presumptive1 ,,partially ,,confirmed ,,and ,,completed ,,tests ,,for ,b4 ,,coli4 ,steps in procedure4 ,further procedure required4 ,i4 ,inoculate lactose broth fermentation tubes2 incubate #bd hours at #cg ,c42 observe gas-formation in each tube4 #a4 ,gas-formation1 #aj per cent4 or more2 constitutes positive presumptive test4 7a7 ,for other than smallest portion of any sample showing gas at this time1 and for all portions1 including smallest1 of sewage and raw water this test is sufficient4 ,none 7b7 ,for smallest gas-forming portion1 except in examinations of sewage and raw water4 ,,iii #b4 ,gas-formation less than #aj per cent4 in #bd hours2 inconclusive4 ,,ii ,,ii4 ,incubate an additional #bd hours1 making a total of #dh hours' incubation2 observe gas-formation4 #a4 ,gas-formation1 any amount2 constitutes doubtful test1 which must always be carried further4 ,,iii #b4 ,no gas-formation in #dh hours2 constitutes final negative test4 ,none ,,iii4 ,make plate from smallest gas-forming portion of sample under examination2 incubate #ah to #bd hours2 observe colonies4 #a4 ,one or more colonies typical in appearance4 7a7 ,if only 8partially confirmed0 test is required,none 7b7 ,if completed test is required1 select two typical colonies for identification4 ,v #b4 ,no typical colonies4 ,,iv ,,iv4 ,replace plate in incubator for an additional #ah to #bd hours2 then1 whether colonies appear typical or not1 select at least two of those which most nearly resemble ,b4 coli4 ,v ,v4 ,transfer each colony fished to3 #a4 ,lactose broth fermentation tube2 incubate not more than #dh hours at #cg ,c4 ,observe gas-formation4 ,none #b4 ,agar slant2 incubate #dh hours at #cg ,c4 7a7 ,if gas formed in lactose broth tube inoculated with corresponding culture ,,vi 7b7 ,if no gas formed in corresponding lactose broth tube1 test is completed and negative4 ,none ,,vi4 ,make stained cover-slip or slide preparation1 and examine microscopically4 #a4 ,if preparation shows non-spore-forming bacilli in apparently pure culture1 demonstration of ,b4 coli is completed4 ,none #b4 ,if preparation fails to show non-spore-forming bacilli or shows them mixed with spore-bearing forms or bacteria of other morphology4 ,,vii ,,vii4 ,replate1 to obtain assuredly pure culture1 select several colonies of bacilli and repeat steps ,v and ,,vi4 ,in order that tests for ,b4 coli may have quantitative significance1 the following general principles and rules should be observed3 ,ordinarily not less than three portions of each sample should be tested1 the portions being even decimal multiples or fractions of a cubic centimeter2 for example1 #aj cc41 #a cc41 #j4a cc41 4#ja cc41 etc4 ,it is essential that the dilutions should be such that the largest amount gives a positive test 7unless the water is such as to give negative tests in #aj cc471 and the smallest dilution1 a negative result4 ,to insure this result1 it is often necessary to plant four or five dilutions1 especially in the examination of a sample of entirely unknown quality4 ,the quantitative value of a series of tests is lost1 unless all or at least a large proportion of the smallest dilutions tested have given negative results4 ,in reporting a single test1 it is preferable merely to record results as observed1 indicating the amounts tested and the result in each1 rather than to attempt expression of the result in numbers of ,b4 coli per cc4 ,in summarizing the results of a series of tests1 however1 it is desirable1 for the sake of simplicity1 to express the results in terms of the numbers of ,b4 coli per cc41 or per #ajj cc4 ,to convert results of fermentation tests to this form1 the result of each test is recorded as indicating a number of ,b4 coli per cc4 equal to the reciprocal of the smallest decimal or multiple fraction of a cubic centimeter giving a positive result4 ,for example1 the result3 #aj cc4 2 #a cc4 2 #j4a cc4 -2 would be recorded as indicating one ,b4 coli per cc4 ,an exception should be made in the case where a negative result is obtained in an amount larger than the smallest portion giving a positive result2 for example1 in a result such as3 #aj cc4 2 #a cc4 -2 #j4a cc4 4 ,in such case1 the result should be recorded as indicating a number of ,b4 coli per cc4 equal to the reciprocal of the dilution next larger than the smallest one giving a positive test1 this being a more probable result4 ,where tests are made in amounts larger than #a cc41 giving average results less than one ,b4 coli per cc41 it is more convenient to express results in terms of the numbers of ,b4 coli per #ajj cc4 ,the following table illustrates the method of recording and averaging results of ,b4 coli tests3 ,result of ,tests in ,amounts ,designated4 ,indicated ,number of ,b4 coli4 #aj cc4 #a cc4 #j4a cc4 4#ja cc4 per cc4 per #ajj cc4 #j4a #aj4 #a4j #ajj4 #aj4j #a1jjj4 #ajj4j #aj1jjj4 #aj4j #a1jjj4 ---------- ---------- ,totals 7for estimating averages7 #aba4a #ab1aaj4 ,average of #e tests #bd4j #b1dbb4 ,the above method of expressing results is not mathematically altogether correct4 ,the average number of ,b4 coli per cc41 as thus estimated1 is not precisely the most probable number calculated by application of the theory of probability4#bbj ,to apply this theory to a correct mathematical solution of any considerable series of results involves1 however1 mathematical calculations so complex as to be impracticable of application in general practice4 ,the simpler method given is therefore considered preferable1 since it is easily applied and the results so expressed are readily comprehensible4 ,in order that results as reported may be checked and carefully valuated1 it is necessary that the report should show not only the average number of ,b4 coli per cc41 but also the number of samples examined2 and1 for each dilution1 the total number of tests made1 and the number 7or per cent47 positive4 #aj4 ,,interpretation ,,of ,,results4 ,while it is not within the province of this report to suggest the proper interpretation of results obtained by the use of the methods herein specified as standard1 the committee feels that a word of caution should be given regarding the significance of the presence in a water of members of the ,b4 coli group as defined in this report4 ,recent work seems to indicate that the ,b4 coli group as herein defined consists of organisms of both fecal and non-fecal origin4 ,therefore care must be exercised in judging the sanitary quality of a water solely from the determination of the presence of members of the group4 #aa4 ,,differentiation ,,of ,,fecal ,,from ,,non-,,fecal ,,members ,,of ,,the ,b4 ,,coli ,,group4 7#a7 ,at least #aj cultures should be used4 ,if possible these should be subcultured from plates made direct from the water since all of the cultures obtained by plating from fermentation tubes may be descendants of a single cell in the water4 ,if cultures from water plates are not available those obtained from plates made as prescribed under ,b 7p4 #aja7 may be used4 7#b7 ,inoculate each culture into dextrose potassium phosphate broth1,h adonite broth1 and gelatin4 ,for additional confirmatory evidence inoculation may be made into tryptophane broth1,i and saccharose broth4 ,the dextrose broth must be incubated at #cj4 ,other sugar broths may be incubated at #cj or #cg as convenient4 ,gelatin should be incubated at #bj4 ,footnote ,h3 7a7 ,peptone ,medium for the ,methyl ,red ,test4 ,to ,make ,one ,liter4 #a4 ,to #hjj cc4 of distilled water add #e grams of ,proteose-,peptone1 ,difco41 or ,witte's ,peptone 7other peptones should not be substituted71 #e grams c4 p4 dextrose1 and #e grams dipotassium hydrogen phosphate 7,k#b;,,hpo#d74 ,a dilute solution of the ,k#b;,,hpo#d should give a distinct pink with phenolphthalein4 #b4 ,heat with occasional stirring over steam for twenty minutes4 #c4 ,filter through folded filter paper1 cool to #bj ,c4 and dilute to #a1jjj cc4 with distilled water4 #d4 ,distribute #aj cc4 portions in sterilized test-tubes4 #e4 ,sterilize by the intermittent method for #bj minutes on three successive days4 ,footnote ,i3 ,tryptophane ,broth for ,indol ,test4 ,to #a1jjj cc4 of distilled water add #j4c gram tryptophane1 #e grams dipotassium hydrogen phosphate 7,k#b;,,hpo#d71 and #a gram peptone4 ,heat until ingredients are thoroughly dissolved1 tube 7#f to #h cc471 and sterilize in autoclave for #ae minutes after the pressure reaches #ae pounds4 ,some ,american peptones are standardized to contain a uniform amount of tryptophane4 ,if such peptone is used the tryptophane in the above formula may be omitted and the peptone increased to #e grams4 7#c7 ,after #dh hours record gas formation in adonite and saccharose broths4 ,determine indol formation in tryptophane broth by adding drop by drop1 to avoid mixing with the medium1 about #a cc4 of a #b per cent4 alcoholic solution of p-dimethyl amido-benzaldehyd1 then a few drops of concentrated hydrochloric acid4 ,the presence of indol is indicated by a red color which is soluble in chloroform4 ,there may be some unconverted tryptophane still present which will give a distinctly blue color which is insoluble in chloroform4 ,a mixture of the two will be either blue or violet4 ,if from such a mixture of colors the red of indol be extracted with chloroform proof of the presence of indol will be complete4 7#d7 ,after #e days apply methyl red test and ,voges-,proskauer test to dextrose broth4 ,methyl ,red ,test4,j ,indicator solution4--,dissolve #j4a gram methyl red in #cjj cc4 alcohol and dilute to #ejj cc4 with distilled water4 ,footnote ,j3 7b7 ,synthetic ,medium for the ,methyl ,red ,test4 ,to ,make ,one ,liter4 ,dissolve #g grams ,na#b;,,hpo#d 7anhydrous7 or #h4h grams ,na#b;,,hpo#d4b;,h#b,o1 #b grams ,k,hphthalate1 #a gram aspartic acid1 and #d grams dextrose in about #hjj cc4 of warm distilled water4 ,when solution is complete1 cool and make up to #a liter at room temperature4 ,heat in an autoclave for #ae minutes after the pressure has reached #ae pounds1 provided the total time of exposure to heat is not more than one-half hour4 ,the hydrogen-ion concentration of the medium is fixed by the composition4 ,it should be very close to ,p,h #g4j1 slightly red with phenol red4 ,all materials should be recrystallized or if used from stock furnished by manufacturers1 should be carefully examined4 ,the di-sodium hydrogen phosphate may be used either as the anhydrous salt obtained by dessication in vacuo at #ajj ,c4 or else as the salt containing two molecules of water of crystallization4 ,this is obtained by exposing the recrystallized ,na#b;,,hpo#d4ab;,h#b,o for two weeks4 ,use #j4hh per cent4 of ,na#b;,,hpo#d4b;,h#b,o4 ,procedure in test4--#a4 ,to #e cc4 of each culture add #e drops of methyl red solution4 #b4 ,record distinct red color as methyl red 1 distinct yellow color as methyl red -1 and intermediate colors as 84 ,voges-,proskauer ,test4#baf ,to the remaining #e cc4 of medium add #e cc4 of a #aj per cent4 solution of potassium hydroxide4 ,allow to stand over night4 ,a positive test is indicated by an eosin pink color4 7#e7 ,gelatin tubes should not be pronounced negative until they have been incubated at least #ae days4 ,the following group reactions indicate the source of the culture with a high degree of probability3 ,methyl red ,b4 coli of fecal origin4 ,voges-,proskauer ,gelatin ,adonite ,indol1 usually ,saccharose1 usually ,methyl red ,b4 arogenes of fecal origin4 ,voges-,proskauer ,gelatin ,adonite ,indol1 usually ,saccharose ,methyl red ,b4 arogenes1 probably not of fecal origin4 ,voges-,proskauer ,gelatin ,adonite ,indol1 usually ,saccharose ,methyl red ,b4 cloacae1 may or may not be of fecal origin4 ,voges-,proskauer ,gelatin ,adonite ,indol1 usually ,saccharose #ab4 ,,routine ,,procedure ,,for ,,examination ,,of ,,samples ,,of ,,water4 ,first ,day3 #a4 ,prepare dilutions as required4 #b4 ,make two 7#b7 gelatin plates from each dilution1 and incubate at #bj ,c4 #c4 ,make two 7#b7 agar plates from each dilution1 and incubate at #cg ,c4 #d4 ,inoculate lactose broth fermentation tubes with appropriate amounts for ,b4 coli tests1 inoculating two 7#b7 tubes with each amount4 ,note3--,where repeated tests are made of water from the same source1 as is customary in the control of public supplies1 it is not necessary to make duplicate plates or fermentation tubes in each dilution4 ,it is sufficient1 in such circumstances1 to make duplicate plates only from the dilution which will most probably give from #be to #bej colonies per plate4 ,second ,day3 #a4 ,count the agar plates made on the first day4 #b4 ,record the number of lactose broth fermentation tubes which show #aj per cent4 7#aj7 or more of gas4 ,note3--,in case only the presumptive test for ,b4 coli is required1 fermentation tubes showing more than #aj per cent4 7#aj7 of gas at this time may be discarded4 ,third ,day3 #a4 ,count gelatin plates made on first day4 #b4 ,record the number of additional fermentation tubes which show #aj per cent4 7#aj7 or more of gas4 #c4 ,make a lactose-litmus-agar or ,endo's medium plate from the smallest portion of each sample showing gas4 ,incubate plate at #cg ,c4 ,note3--,in case the smallest portion in which gas has been formed shows less than #aj per cent4 7#aj7 of gas1 it is well to make a plate also from the next larger portion1 so that1 in case the smallest portion gives a negative end result it may still be possible to demonstrate ,b4 coli in the next larger dilution4 ,fourth ,day3 #a4 ,examine ,endo's medium or lactose-litmus-agar plates4 ,if typical colonies have developed1 select two and transfer each to a lactose broth fermentation tube and an agar slant1 both of which are to be incubated at #cg ,c4 #b4 ,if no typical ,b4 coli colonies are found1 incubate the plates another #bd hours4 ,fifth ,day3 #a4 ,select at least two colonies1 whether typical or not1 from the ,endo's medium or lactose-litmus-agar plates which have been incubated an additional #bd hours2 transfer each to a lactose broth fermentation tube and an agar slant1 and complete the test as for typical colonies4 #b4 ,examine lactose broth fermentation tubes inoculated from plates on the previous day4 ,tubes in which gas has been formed may be discarded after the result has been recorded4 ,those in which no gas has formed should be incubated an additional #bd hours4 ,sixth ,day3 #a4 ,examine lactose broth fermentation tubes reincubated the previous day4 #b4 ,examine microscopically agar slants corresponding to lactose fermentation tubes inoculated from plate colonies and showing gas-formation4 ,,bacteriological ,,bibliography4 ,bibliography #bja3 ,,bovie1 ,w4 ,t4 ,a ,direct ,reading ,potentiometer for ,measuring and ,recording both the ,actual and the ,total ,reaction of ,solutions4 ,jour4 ,med4 ,research1 #cc1 #aiae-af1 #bie4 ,bibliography #bjb3 ,,breed1 ,r4 ,s4 and ,,dotterrer1 ,w4 ,d4 ,the ,number of ,colonies ,allowable on ,satisfactory ,agar ,plates4 ,jour4 of ,bact41 #a1 #aiaf1 #cba4 ,bibliography #bjc3 ,,browne1 ,w4 ,w4 ,a ,comparative ,study of the ,smith ,fermentation ,tube and the ,inverted ,vial in the ,determination of ,sugar ,fermentation4 ,amer4 ,jour4 of ,public ,health1 #c1 #aiac1 #gja4 ,bibliography #bjd3 ,,clark1 ,w4 ,m4 ,an ,hydrogen ,electrode ,vessel4 ,jour4 ,biol4 ,chem41 #bc1 #aiae1 #dge4 ,bibliography #bje3 ,,clark1 ,w4 ,m4 ,the 8,reaction0 of ,bacteriological ,culture ,media4 ,jour4 of ,inf4 ,diseases1 #ag1 #aiae1 #aji4 ,bibliography #bjf3 ,,clark1 ,w4 ,m4 ,the ,final ,hydrogen ,ion ,concentrations of ,cultures of ,bacillus ,coli4 ,science1 n4 s4 #db1 #aiae1 #ga4 ,bibliography #bjg3 ,,clark1 ,w4 ,m4 and ,,lubs1 ,h4 ,a4 ,hydrogen ,electrode ,potentials of ,phthalate1 ,phosphate1 and ,borate ,buffer ,mixtures4 ,jour4 ,biol4 ,chem41 #be1 #aiaf1 #dgi4 ,bibliography #bjh3 ,,clark1 ,w4 ,m4 and ,,lubs1 ,h4 ,a4 ,the ,differentiation of ,bacteria of the ,colon-,arogenes ,family by the ,use of ,indicators4 ,jour4 of ,inf4 ,diseases1 #ag1 #aiae1 #afj4 ,bibliography #bji3 ,,endo1 ,s4 ,ueber ein ,verfahren zum ,nachweis der ,typhusbacillen ,centbl4 f4 ,bakt4 ,erste ,abt41 #ce1 #aijc-d1 #aji4 ,bibliography #baj3 ,,gillespie1 ,l4 ,j4 ,the ,reaction of ,soil and ,measurements of ,hydrogen ,ion ,concentration4 ,jour4 ,wash4 ,acad4 of ,sciences1 #f1 #aiaf1 #g4 ,bibliography #baa3 ,,hill1 ,h4 ,w4 ,porous ,tops for ,petri ,dishes4 ,jour4 ,med4 ,research1 #ac1 #aijd1 #ic4 ,bibliography #bab3 ,,hill1 ,h4 ,w4 ,the ,mathematics of the ,bacterial ,count4 ,public ,health ,reports and ,papers1 #cc1 #aijg1 #aaj4 ,bibliography #bac3 ,,itano1 ,a4 ,the ,relation of ,hydrogen ,ion ,concentration of ,media to the ,proteolytic ,activity of ,bacillus ,subtilis4 ,bulletin #afg1 #aiaf1 ,mass4 ,agric4 ,ex4 ,station4 ,bibliography #bad3 ,,kendall1 ,a4 ,i4 and ,,walker1 ,a4 ,w4 ,the ,isolation of ,bacillus ,dysenteriae from ,stools4 ,jour4 ,med4 ,research1 #bc1 #aiaj1 #dha4 ,bibliography #bae3 ,,kinyoun1 ,j4 ,j4 and ,,deiter1 ,l4 ,v4 ,on the ,preparation of ,endo's ,medium4 ,amer4 ,jour4 ,public ,health1 n4 s4 #b1 #aiab1 #igi4 ,bibliography #baf3 ,,levine1 ,m4 ,on the ,significance of the ,voges-,proskauer ,reaction4 ,jour4 of ,bacteriology1 #a1 #aiaf1 #aec4 ,bibliography #bag3 ,,lubs1 ,h4 ,a4 and ,,clark1 ,w4 ,m4 ,on ,some ,new ,indicators for the ,colorimetric ,determination of ,hydrogen-ion ,concentration4 ,jour4 ,wash4 ,acad4 of ,sciences1 #e1 #aiae1 #fji4 ,bibliography #bah3 ,,mcclendon1 ,j4 ,f4 ,new ,hydrogen ,electrodes and ,rapid ,methods of ,determining ,hydrogen ,ion ,concentrations4 ,amer4 ,jour4 of ,physiology1 #ch1 #aiae1 #ahj4 ,bibliography #bai3 ,,mcclendon1 ,j4 ,f4 ,a ,direct ,reading ,potentiometer for ,measuring ,hydrogen ,ion ,concentrations4 ,amer4 ,jour4 of ,physiology1 #ch1 #aiae1 #ahf4 ,bibliography #bbj3 ,,mccrady1 ,m4 ,h4 ,the ,numerical ,interpretation of ,fermentation-tube ,results4 ,jour4 ,inf4 ,diseases1 #ag1 #aiae1 #ahc4 ,bibliography #bba3 ,,noyes1 ,h4 ,a4 ,agar ,agar for ,bacteriological ,use4 ,science1 n4 s4 #dd1 #aiaf1 #gig4 ,bibliography #bbb3 ,,rogers1 ,l4 ,a41 ,,clark1 ,w4 ,m4 and ,,davis1 ,b4 ,j4 ,the ,colon ,group of ,bacteria4 ,jour4 of ,inf4 ,diseases1 #ad1 #aiad1 #daa4 ,bibliography #bbc3 ,,rogers1 ,l4 ,a41 ,,clark1 ,w4 ,m4 and ,,evans1 ,a4 ,c4 ,the ,characteristics of ,bacteria of the ,colon ,type ,found in ,bovine ,feces4 ,jour4 of ,inf4 ,diseases1 #ae1 #aiad1 #ii4 ,bibliography #bbd3 ,,rogers1 ,l4 ,a41 ,,clark1 ,w4 ,m4 and ,,evans1 ,a4 ,c4 ,the ,characteristics of ,bacteria of the ,colon ,type ,occurring on ,grains4 ,jour4 of ,inf4 ,diseases1 #ag1 #aiae1 #acg4 ,bibliography #bbe3 ,,smith1 ,h4 ,m4 ,the ,seaweed ,industries of ,japan4 ,bulletin of the ,bureau of ,fisheries1 #bd1 #aijd1 #ace4 ,bibliography #bbf3 ,s,,rensen1 ,s4 ,p4 ,l4 ,enzymstudien4 ,biochem4 ,ztschr41 #ba1 #aiji1 #aca and #bja4 ,bibliography #bbg3 ,,whipple1 ,g4 ,c4 ,on the ,necessity of ,cultivating ,water ,bacteria in an ,atmosphere ,saturated with ,moisture4 ,tech4 ,quart41 #ab1 #ahii1 #bgf4 ,bibliography #bbh3 ,,whittaker1 ,h4 ,a4 ,the ,source1 ,manufacture and ,composition of ,commercial ,agar-agar4 ,jour4 ,amer4 ,pub4 ,health ,assoc41 n4 s4 #a1 #aiaa1 #fcb4 ,bibliography #bbi3 ,,clark1 ,w4 ,m4 and ,,lubs1 ,h4 ,a4 ,the colorimetric determination of the hydrogen-ion concentration of bacteriological culture media4 ,jour4 ,wash4 ,acad4 ,sciences1 #f1 #aiaf1 #dhc4 ,bibliography #bcj3 ,,clark1 ,w4 ,m4 and ,,lubs1 ,h4 ,a4 ,the colorimetric determination of hydrogen-ion concentration and its application in bacteriology4 ,jour4 of ,bact41 #b1 #aiai1 #a and #aji4 ,bibliography #bca3 ,,cohen1 ,b4 and ,,clark1 ,w4 ,m4 ,the growth of certain bacteria in media of different hydrogen-ion concentrations4 ,jour4 of ,bact41 #d1 #aiai1 #dji4 ,bibliography #bcb3 ,,fennel1 ,e4 ,a4 and ,,fisher1 ,m4 ,a4 ,adjustment of culture medium reactions4 ,jour4 of ,inf4 ,diseases1 #be1 #aiai1 #ddd4 ,bibliography #bcc3 ,,jones1 ,h4 ,m4 ,a rapid hydrogen-ion electrode method for the determination of hydrogen-ion concentrations in bacterial cultures or other turbid or colored solutions4 ,jour4 of ,inf4 ,diseases1 #be1 #aiai1 #bfb4 ,,index4 ,a4 ,acidity1 determination of1 #ci4 ,acids1 mineral1 #da4 ,agar1 nutrient1 #id1 #if4 lactose-litmus1 #ig4 ,alkali carbonates1 #ci4 ,alkalinity1 determination of1 #ce4 ,albuminoid nitrogen1 #bj4 ,aluminium sulfate1 determination of1 #da4 analysis of1 #gh4 ,aluminium and iron1 determination of1 #eg4 ,ammonia nitrogen1 determination of1 #ae4 ,apparatus1 bacteriological1 #ic4 ,application of colon group tests1 #ajb4 ,arsenic1 determination of1 #fc4 ,azolitmin solution1 #if4 ,b4 ,bacillus arogenes1 reactions1 #ajh4 cloacae1 reactions1 #ajh4 coli1 reactions1 #ajh4 ,b4 coli group1 tests1 #ajj4 application of1 #ajb4 fecal and non-fecal1 #ajf4 summary of tests1 #ajd4 ,bacteriological examination1 #ic4 bibliography1 #aaj4 ,basicity ratio1 #hj4 ,bibliography1 bacteriological1 #aaj4 chemical1 #hb4 microscopical1 #ia4 ,biochemical oxygen demand1 #ga4 in sludge and mud1 #gf4 ,bismuthate method 7,mn71 #di4 ,boric acid1 #fc4 ,bottles1 sample1 #a1 #ic4 dilution1 #ic4 ,bromine and iodine1 determination of1 #fa4 ,broth1 nutrient1 #ie4 sugar1 #ie4 ,c4 ,calcium1 determination of1 #eg4 ,carbon dioxide1 determination of1 #dj4 ,chemical analysis1 water and sewage1 #a4 bibliography1 #hb4 ,chemicals1 analysis of1 #gg4 ,chloride1 determination of1 #da4 ,chlorine1 determination of1 #fd4 ,coefficient of fineness1 #h4 ,collection of samples1 bacteriological1 #ic4 chemical1 #a4 ,colon group1 tests 7see 8,b4 coli071 #ajj4 ,color1 determination of1 #i4 ,copper1 determination of1 #ec1 #ee4 ,counting 7bacterial71 #ii4 ,cultural characters of colon group1 #ajh4 ,culture media1 #id4 azolitmin solution1 #if4 ,endo's medium1 #ig4 litmus-lactose-agar1 #ig4 litmus solution1 #if4 methyl red test1 #ajg4 nutrient agar1 #if4 nutrient broth1 #ie4 nutrient gelatin1 #if4 sterilization1 #ie4 sugar broth1 #ie4 titration1 #id4 tryptophane broth1 #ajg4 ,d4 ,dilution 7bacteriological71 #ih4 ,dissolved oxygen1 #fe4 ,e4 ,effluents1 relative stability of1 #fi4 biochemical1 oxygen1 demand of1 #ga4 ,endo's medium1 #ig4 ,erythrosine indicator1 #cf4 ,ether--soluble matter1 #fi4 in sludge and mud1 #ge4 ,evaporation1 #bi4 ,expression of results 7see under 8,results074 ,f4 ,fat1 determination of1 #fi1 #ge4 ,fecal and non-fecal members1 colon group1 #ajf4 ,fermentation tubes1 #ic4 ,ferrous sulfide in sludge and mud1 #gf4 ,ferrous iron1 determination of1 #dg4 ,ferric iron1 determination of1 #dh4 ,fineness1 coefficient of1 #h4 ,g4 ,gelatin media1 #id1 #if4 ,h4 ,hardness1 determination of1 #cj4 bicarbonate1 #cg4 carbonate1 #ch4 hydroxide1 #ch4 non-carbonate1 #cd4 temporary1 #cd4 ,hydrogen sulfide1 determination of1 #fc4 ,hydrogen-ion determination1 #id4 ,i4 ,ignition1 loss on1 #cj4 ,incubation1 #ii4 ,indol test1 broth for1 #ajg4 ,indicators1 #cf1 #id1 #ajg4 ,iodine and bromine1 determination of1 #fa4 ,iron and ,aluminium1 separation1 #eg4 analysis of1 #gi4 ,iron1 determination of1 #dc4 standards1 #de4 sulfate1 determination of1 #da4 analysis of1 #ha4 ,l4 ,lacmoid indicator1 #cf4 ,lead1 determination of1 #ea1 #ee4 ,lime1 analysis of1 #hj4 ,lithium1 determination of1 #fj4 ,litmus reagent1 #id4 lactose-agar1 #ig4 solution1 #if4 ,m4 ,manganese1 determination of1 #dh4 ,materials1 bacteriological1 #ic4 ,meat extract1 #ic4 ,media1 culture 7see 8,culture media071 #id-g1 #ajg4 ,methyl orange indicator1 #cg4 ,methyl red media1 #ajg4 test1 #ajg4 ,microscopical bibliography1 #ia4 examination1 #hi4 ,mineral analysis1 #ef4 ,moisture in sludge and mud1 #gd4 ,mud deposits1 analysis1 #gc4 ,n4 ,nessler's reagent1 color standards1 #aj4 ammonia determination1 #ai4 ,nitrogen1 #ae4 ammonia1 #ae4 albuminoid1 #bj4 ,nitrogen1 in sludge and mud1 #gd4 nitrate1 #bc4 nitrite1 #bb4 organic1 #ba4 total1 #be4 ,nutrient media 7see 8,culture media071 #id1 #ajg4 ,o4 ,odor1 #ab4 ,organic nitrogen1 #ba4 ,oxygen consumed1 #be4 demand1 biochemical1 #ga4 dissolved1 #fe4 in fresh and sea water 7table71 #fh4 ,p4 ,peptone1 authorized brands1 #ic4 ,persulfate method 7,mn71 #dh4 ,petri dishes1 #ic4 ,phenoldisulfonic acid method 7nitrate71 #bc4 ,phenolphthalein indicator1 #cf1 #id4 ,physical examination1 #d4 ,pipettes1 bacteriological1 #ic4 ,plating1 bacteriological1 #ii4 ,platinum-cobalt color standard1 #i4 wire turbidity1 #e4 ,potassium1 determination of1 #ei4 ,presumptive tests1 colon group1 #ajb4 ,r4 ,reactions of colon group1 #ajh4 ,reaction of culture media1 #id4 of sludge and mud1 #gc4 ,reduction method 7nitrate71 #bd4 ,relative stability method1 #ga4 ,residue on evaporation1 #bi4 ,results1 expression of1 bacteriological1 #ajc4 chemical examination1 #ad4 color1 #h4 odor1 #ab4 ,results1 interpretation of 7bacteriological71 #ajf4 ,routine procedure 7bacteriological71 #ajh4 ,s4 ,samples1 bacterial1 #ic4 bottles1 #a4 chemical1 #a4 interval before analysis of1 #b4 quantity required1 #a4 representative1 #c4 sludge and mud1 #gc4 ,sewage sludge1 analysis1 #gc4 ,silica1 determination of1 #ef4 ,soda ash1 analysis of1 #hb4 ,soap method 7hardness71 #ca4 ,sodium and potassium1 #eh4 ,solids1 total1 fixed1 volatile1 #bi4 ,specific gravity of sludge and mud1 #gd4 ,stability1 relative1 of effluents1 #fi4 method1 relative1 #ga4 ,standards1 ammonia1 #ag4 chlorine1 #fe4 color1 #i4 hardness1 #cb4 iron1 #de4 ,nessler1 color1 #aj4 platinum-cobalt1 #aj4 turbidity1 #d4 ,sterilization of media1 #ie4 ,storage of samples1 #b1 #ih4 ,sugars for media1 #id4 ,sugar broths1 #ie4 ,sulfate1 ,k and ,na1 #eh4 ,suspended matter1 #cj4 ,t4 ,tin1 determination of1 #ed1 #ee4 ,tintometer1 ,lovibond1 #aa4 ,titration of media1 #id4 ,total nitrogen1 #be4 residue on evaporation1 #bi4 ,tryptophane broth1 #ajg4 ,turbidity1 #d4 coefficient of fineness1 #h4 platinum wire method1 #e4 rod1 graduation1 #f4 standard1 #d4 turbidimetric method1 #g4 turbidometer1 graduation1 #h4 ,v4 ,voges-,proskauer test1 #ajg4 ,volatile matter1 #bi4 in sludge and mud1 #gd4 ,z4 ,zinc1 #eb4 ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 ,silently corrected typographical errors and variations in spelling4 #b4 ,archaic1 non-standard1 and uncertain spellings retained as printed4 #c4 ,the ,chemical ,bibliography was reformatted in footnote style4 #d4 ,the ,bacteriological ,bibliography was reformatted in footnote style and the numbering was increased by #bjj4 #e4 ,enclosed italics font in underscores4