,.%^'av ?*?•■?* ^' ^ -.a if,' f'^**^ 1^^ - m C JtuL crY\ ^'^ ^'*"' '" " REPORT OF THE COMMITTEE ON EDITING TENTATIVE AND OFFICIAL Methods of Analysis THE ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS WILLIAMS & WILKINS COMPANY BALTIMORE. U. S. A. 1916 5 f\l^ MAIN imRARY AGRIC. DEPT. COPTRIQHT, 1916 BY The Association of Official Aqeicui-tural Chemists COMPOSED AND PRINTED ATTHK WAVERLY PRESS Bt THB WiLIJAMS & WiLKINS COMPAHT Baltimore, Md., U. 8 A. CONTENTS I. Fertilizers 1 II. Soils 17 III. Plant Constituents 29 IV. Waters 35 V. Tanning Materials 53 VI. Leathers 59 VII. Insecticides and Fungicides 63 VIII. Foods and Feeding Stuffs 79 IX. Saccharine Products 121 X. Food Preservatives 141 XI. Coloring Matters in Foods 155 XII. Metals in Foods 171 XIII. Fruits and Fruit Products 177 XIV. Canned Vegetables 185 XV. Cereal Foods 187 XVI. Wines 193 XVII. Distilled Liquors 243 XVIII. Beers 249 XIX. Vinegars 253 XX. Flavoring Extracts 259 XXI. Meat and Meat Products 271 XXII. Dairy Products 287 XXIII. Fats and Oils 299 XXIV. Spices and Other Condiments 317 XXV. Cacao Products 327 XXVI. Coffees 331 XXVII. Tea 335 XXVIII. Baking Powders and Their Ingredients 339 XXIX. Drugs 351 Index 367 793413 ILLUSTRATIONS Figure 1. Combustion tube for the determination of total nitrogen 9 Figure 2. Parr's apparatus for the determination of carbon dioxid 18 Figure 3. Modified Marr apparatus for determining carbon dioxid 19 Figure 4. Metal extractor used for extracting tanning materials 56 Figure 5. Apparatus for distillation of arsenic chlorid 64 Figure 6. Apparatus for detection of formic acid 153 Figure 7. Apparatus for the determination of arsenic 172 Figure 8. Apparatus for the determination of volatile acids 239 Figure 9. Apparatus for the Folin ammonia determination 275 Figure 10. Van Slyke apparatus for the determination of amino nitrogen 282 Figure 11. Details of the deaminizing bulb and connection 283 Figure 12. Apparatus for the melting point determination 303 Figure 13. Apparatus for the determination of the Polenske number 309 Figure 14. Knorr's apparatus for the determination of carbon dioxid 339 Figure 15. Heidenhain's apparatus for the determination of carbon dioxid 341 TABLES Table 1. Munson and Walker's Table. For calculating dextrose, invert sugar alone, invert sugar in the presence of sucrose (0.4 gram and 2 grams total sugar), lactose (two forms), and maltose (anhydrous and crystallized) 88 Table 2. Herzfeld's Table. For the determination of invert sugar in mate- rials containing 1.5%, or less, of invert sugar and 98.5%, or more, of sucrose 99 Table 3. Meissl and Killer's factors for determinations in materials in which, of the total sugars present, 1.5%, or more, is invert sugar,^ and 98.5%, or less, is sucrose 100 Table 4. Meissl's Table. For the determination of invert sugar alone 101 Table 5. For the determination of maltose 103 Table 6. For the determination of lactose 105 Table 7. AUihn's Table. For the determination of dextrose 107 Table 8. Krober's Table. For determining pentoses and pentosans 112 Table 9. For correction of the readings of the Brix spindle when made at other than the standard temperature, 17.5°C 123 Table 10. For the comparison of specific gravities at j^g, ", degrees Brix and degrees Baume 124 Table 11. Densities of solutions of cane sugar at 20°C 125 Table 12. Geerlig's Table. For dry substance in sugar-house products by the Abbe ref ractometer, at 2S°C 127 Table 13. Corrections for temperature 128 Table 14. Color reactions produced on dyed fibers by various reagents 161 Table 15. Behavior of certain natural coloring matters with common reagents.. 166 Table 16. Alcohol Table. For calculating the percentages of alcohol in mix- tures of ethyl alcohol and water from their specific gravities 194 Table 17. Alcohol Table. For calculating the percentages of alcohol in mix- tures of ethyl alcohol and water from their Zeiss immersion refrac- tometer readings at 17.5°-25°C 208 Table 18. Scale readings of the Zeiss immersion refractometer at 20''C., corre- sponding to each per cent by weight of methyl and ethyl alcohols. . 247 Table 19. Volumes of milk corresponding to a lactose double normal weight . . . 288 Table 20. Butyro-ref ractometer readings and indices of refraction 301 REPORT OF THE COMMITTEE ON EDITING METHODS ^ —OF ANALYSIS. Washington, D. C, NovemlxM- 16, 191;"). To The President and Members of the/ Association of Official Agricul- tural Chemists. 1— Gentlemen: — Your committee on editing methods of analysis begs leave to report that it has completed the work assigned and herewith submits for your consideration the revised methods. The committee has included all authorized changes and addi- tions, has eliminated obsolete methods in so far as possible, rewritten the text where parts appeared obscure, and made such consolidations of general methods and rearrangements as in its opinion would promote brevity and clearness. In order that the members of the Association may have an opportunity to criti- cize the revised methods it is suggested by your committee that this report be published in the Journal of the Association with a view to final adoption of the metliods in 19IG. Respectfully submitted, Committee on Editing Methods of Analysis. R. E. DooLiTTLE, Chairman, A. F. Seeker, W. A. Withers, G. W. Hoover, J. P. Street, B. L. Hartwell. Editorial Note: — The Board of Editors submits the following comment upon the report of the Committee on Editing Methods of Analysis: Inasmuch as the methods of analysis as prescribed by this Association have been adopted, by regulation, for the enforcement of the Federal Food and Drugs Act and, by law, in many of the States for the enforcement of State laws, certain safe- guards to protect their integrity are provided by the Association's Constitution and By-Laws. The Constitution and By-Laws provide for Official and Provisional Methods only. At the last meeting of the Association it was suggested that the "Provisional" methods be designated as '"Tentative" and the committee was instructed at the afternoon session, Wednesdaj', November 17, 1915, to make their report accordingly. The phraseology of the Constitution was not changed, however, but was referred to a committee to be reported upon at the 1916 meeting. Therefore, in the present report the word "Tentative" has been substituted for the word "Provisional", though the term "Provisional" must be formally retained until the Constitution shall have been changed. Changes in methods cannot be made until an opportunity has been given members of the Association to test them. Before a method can be adopted as O.Ticial, it must have been tested through cooperative work and must have been recommended by the appropriate referee for at least two years. Official Methods, therefore, are those which have been thoroughly tested and which, in the opinion of the Associa- tion, yield accurate results in the hands of its members. In other words, they are believed to render as absolutely correct results as are possible in the existing state of knowledge concerning the determination in question. Provisional Methods are those which, while in the opinion of the Association yielding dependable results for comparison, have not as yet been tested so thoroughly as those that have been adopted officially. They are believed to be the best of the kind which have been tested by the Association but which for reasons stated have not the standing of Official Methods. The methods in the form last promulgated by the Association, either in Bulletin 107 (Revised) or as published in their Proceedings of the last eight years, are as yet the only ones adopted by the Association. It should be clearly understood that the revised methods as published herewith are simjjly the report of the Committee on Editing Methods of Analysis, including the recommendations adopted at the 1915 meeting, and at the present time have not been officially adopted. The methods are printed at this time to enable the mem- bers of the Association to study and criticize them so that they may be able to vote on them intelligently at the 1916 meeting at which time the matter will come up for final action. RECOMMENDATIONS FOR OFFICIAL AND TENTATIVE METHODS OF ANALYSIS, AS PRESENTED AT THE ANNUAL MEETING OF THE ASSO- CIATION OF OFFICIAL AGRICUL- TURAL CHEMISTS, NOVEMBER 16 AND 17, 1915. I. FERTILIZERS. GENERAL METHODS. 1 MECHANICAL ANALYSIS OF BONE AND TANKAGE.— TENTATIVE. Transfer 100 grams of the original material to a sieve having circular openings 1/50 inch (0.5 mm.) in diameter. Sift, breaking the lumps by means of a soft rubber pestle if the material has a tendency to cake. Weigh the coarse portion remaining on the sieve. Determine the fine portion by difference. 2 PREPARATION OF SAMPLE.— OFFICIAL. Reduce the gross sample by quartering to an amount sufficient for analytical purposes. Transfer to a sieve having circular openings 1/25 inch (1 mm.) in diameter, sift, breaking the lumps with a soft rubber pestle. Grind in a mortar the part re- maining on the sieve until the particles will pass through. Mi.\ thoroughly and preserve in tightly stoppered bottles. Grind and sift as rapidly as possible to avoid loss or gain of moisture during the operation. Note: p. 59-154 (as vol.2, no. 2, part 1. Aug. 15, 1916 of the Journal of the Association of Official Agricultural ■-^:, Chemists) were first published as vol.2, no.l, part 2, ^ May 15, 1916, incorrectly paged 1-96. «i t REAGENTS. (a) Molybdate solution. — Dissolve 100 grams of molybdic acid in dilute ammo- nium hydroxid (144 cc. of ammonium hydroxid (sp. gr. 0.90) and 271 cc. of water); pour this solution slowly and with constant stirring into dilute nitric acid (4S9 cc. of nitric acid (sp. gr. 1.42) and IMS cc. of water). Keep the mixture in a warm place for several days or until a portion heated to 40°C. deposits no yellow precipitate of ammonium phosphomolybdate. Decant the solution from any sediment and preserve in glass-stoppered vessels. (b) Ammonium nitrate sohition. — Dissolve 200 grams of commercial ammonium nitrate, phosphate free, in water and dilute to 2 liters. (C) Magnesia mixture. — Dissolve 22 grams of recently ignited calcined magnesia in dilute hydrochloric acid, avoiding an excess of the latter. Add a little calcined magnesia in excess, and boil a few minutes to precipitate iron, aluminium, and phos- 1 RECOMMENDATIONS FOR OFFICIAL AND TENTATIVE METHODS OF ANALYSIS, AS PRESENTED AT THE ANNUAL MEETING OF THE ASSO- CIATION OF OFFICIAL AGRICUL- TURAL CHEMISTS, NOVEMBER 16 AND 17, 1915. I. FERTILIZERS. GENERAL METHODS. 1 MECHANICAL ANALYSIS OF BONE AND TANKAGE.-TENTATIVE. Transfer 100 grams of the original material to a sieve having circular openings 1/50 inch (0.5 mm.) in diameter. Sift, breaking the lumps by means of a soft rubber pestle if the material has a tendency to cake. Weigh the coarse portion remaining on the sieve. Determine the fine portion by difference. 2 PREPARATION OF SAMPLE.— OFFICIAL. Reduce the gross sample by quartering to an amount sufficient for analytical purposes. Transfer to a sieve having circular openings 1/25 inch (1 mm.) in diameter, sift, breaking the lumps with a soft rubber pestle. Grind in a mortar the part re- maining on the sieve until the particles will pass through. Mix thoroughly and preserve in tightly stoppered bottles. Grind and sift as rapidly as possible to avoid loss or gain of moisture during the operation. 3 MOISTURE.— OFFICIAL. Heat 2 grams of the sample prepared as in 2 for 5 hours in a water oven at the temperature of boiling water. In the case of potash salts, sodium nitrate, and ammonium sulphate heat at about 130°C. to constant weight. The loss in weight is considered as moisture. TOTAL PHOSPHORIC ACID. Gravimetric Method. — Official. 4 REAGENTS. (a) Molybdate solution. — Dissolve 100 grams of molybdic acid in dilute ammo- nium hydroxid (141 cc. of ammonium hydroxid (sp. gr. 0.90) and 271 cc. of water); pour this solution slowly and with constant stirring into dilute nitric acid (4S9 cc. of nitric acid (sp. gr. 1.42) and IMS cc. of water). Keep the mixture in a warm place for several days or until a portion heated to 40°C. deposits no yellow precipitate of ammonium phosphomolybdate. Decant the solution from any sediment and preserve in glass-stoppered vessels. (b) Ammonium nitrate solution. — Dissolve 200 grams of commercial ammonium nitrate, phosphate free, in water and dilute to 2 liters. (C) Magnesia mixture. — Dissolve 22 grams of recently ignited calcined magnesia in dilute hydrochloric acic|, avoiding an excess of the latter. Add a little calcined magnesia in excess, and boil a few minutes to precipitate iron, aluminium, and phos- 1 2 METHODS OF ANALYSIS [Chap. phoricacid; filter; add 280 grams of ammonium chlorid, 2G1 cc. of ammonium liydrox- id (sp. gr. 0.90) and dilute to 2 liters. Instead of the solution of 22 grams of cal- cined magnesia, 110 grams of crystallized magnesium chlorid (MgCUGIIiiO) dissolved in water may be used, then add 280 grams of ammonium chlorid and proceed as above. (d) Dilute ammonium hydroxid for washing. — Dilute 100 cc. of ammonium hy- droxid (sp. gr. 0.90) to 1 liter. (e) Magnesium nitrate solution. — Dissolve 320 grams of calcined magnesia in nitric acid, avoiding an excess of the latter; then add a little calcined magnesia in excess, boil, filter from the excess of magnesia, ferric oxid, etc., and dilute to 2 liters. 5 PREPAJIATION OF SOLUTION. Treair 2 or 2.5 gi-ams of the sample by one of the methods given below: (a) Ignite", and di.ssolve in hydrochloric acid. .(b)-Evaponite.' with 5 cc. of magnesium nitrate, ignite, and dissolve in hydro- chtoric aci'd; - • ' - (C) Boil with 20-30 cc. of strong sulphuric acid in a Kjeldahl flask, adding 2-4 grams of sodium or potassium nitrate at the beginning of the digestion and a small quantity after the solution has become nearly colorless, or adding the nitrate in small portions from time to time. After the solution is colorless add 150 cc. of water, and boil for a few minutes. (d) Digest in a Kjeldahl flask with strong sulphuric acid and such other re- agents as are used in either the plain or modified Kjeldahl or Gunning method for estimating nitrogen. Do not add any potassium permanganate, but after the solution has become colorless add about 100 cc. of water and boil for a few minutes. (e) Dissolve in 30 cc. of concentrated nitric acid and a small quantity of hydro- chloric acid and boil until organic matter is destroyed. (f) Add 30 cc. of concentrated hydrochloric acid, heat and add cautiously, in small quantities at a time, about 0.5 gram of finely pulverized potassium chlorate to destroy organic matter. (g) Dissolve in 15-30 cc. of strong hydrochloric acid and 3-10 cc. of nitric acid. This method is recommended for fertilizers containing much iron or aluminium phosphate. After solution, cool, dilute to 200 cc. or to 250 cc. if a 2.5 gram sample was used. Mix, and pour on a dry filter. 6 DETERMINATION. Take an aliquot of the solution prepared as directed above, corresponding to 0.25 gram, 0.50 gram, or 1 gram, neutralize with ammonium hydroxid, and clear with a few drops of nitric acid. In case hydrochloric or sulphuric acid has been used as a solvent, add about 15 grams of dr}' ammonium nitrate or a solution containing that amount. To the hot solution add 60-80 cc. of the molybdate solution for every decigram of phosphoric acid (P2O5) that is present. Digest at about 65°C. for an hour, and determine if the phosphoric acid has been completely precipitated by the addition of more molybdate solution to the clear supernatant liquid. Fil- ter and wash with cold water or, preferably, ammonium nitrate solution. Dissolve the precipitate on the filter with ammonium hydroxid and hot water and wash into a beaker to a bulk of not more than 100 cc. Nearly neutralize with hydrochloric acid, cool, and add magnesia mixture from a burette; add slowly (about 1 drop per second), stirring vigorously. After 15 minutes add 12 cc. of ammonium hydroxid (sp. gr. 0.90). Let stand till the supernatant liquid is clear (2 hours is usually enough) filter, wash with the dilute ammonium hydroxid until the washings are I] FERTILIZERS 3 practically free from chlorin, dry the filter and precipitate and transfer the latter to a weighed porcelain crucible. Ignite the filter separately and add its ash to the precipitate in the crucible. Ignite to whiteness or to a grayish white, weigh, and calculate to phosphoric acid (P2O5). Volumetric Method. — Official. 7 REAGENTS. (a) Molyhdate solution. — To 100 cc. of molybdate solution prepared as directed in 4 (a), add 5 cc. of nitric acid (sp. gr. 1.42). This solution should be filtered im- mediately before using. (b) Standard sodium or potassium hydroxid solution. — Dilute 323.81 cc. of N/1 alkali, free from carbonates, to 1 liter. 100 cc. of the solution should neutralize 32.38 cc. of N/1 acid; 1 cc. is equivalent to 1 mg. of P2O5 (1% of F2O5 on a basis of 0.1 gram of substance). (C) Standard acid solution. — Prepare an acid solution corresponding to the, or to one-half of the, strength of (b), and standardize by titration against that solution, using phenolphthalein as indicator. Hydrochloric or nitric acid may be used. (d) Phenolphthalein solution. — Dissolve 1 gram of phenolphthalein in 100 cc. of alcohol. 8 PREPARATION OF SOLUTION. Dissolve according to 5 (b), (e), (f), or (g), preferably by (e), when these acids are a suitable solvent, and dilute to 200 cc. with water. 9 DETERMINATION. (a) For percentages of 5 or below use an aliqifot corresponding to 0.4 gram of substance, for percentages between 5 and 20 use an aliquot corresponding to 0.2 gram of substance, and for percentages above 20 use an aliquot corresponding to 0.1 gram of substance. Add 5-10 cc. of nitric acid, depending on the method of solution (or the equivalent in ammonium nitrate), nearly neutralize with ammonium hydroxid, dilute to 75-100 cc, heat in a water bath to 60°-65°C., and for percentages below 5 add 20-25 cc. of freshly filtered molybdate solution. For percentages be- tween 5 and 20 add 30-35 cc. of molybdate solution. For percentages greater than 20 add sufficient molybdate solution to insure complete precipitation. Stir, let stand in the bath about 15 minutes, filter at once, wash once or twice with water by decantation, using 25-30 cc. each time, agitate the precipitate thoroughly and allow to settle; transfer to the filter and wash with cold water until the filtrate from 2 fillings of the filter yields a pink color upon the addition of phenolphthalein and 1 drop of the standard alkali. Transfer the precipitate and filter to a beaker or pre- cipitating vessel, dissolve the precipitate in a small excess of the standard alkali, add a few drops of phenolphthalein solution, and titrate with the standard acid. (b) Proceed as in (a) with this exception: Heat in a water bath at 45°-50''C., add the molybdate solution, and allow to remain in the bath with occasional stirring for 30 minutes. (C) Proceed as in (a) to the point where the solution is ready to place in the water bath. Then cool the solution to room temperature, add molybdate solution at the rate of 75 cc. for each decigram of phosphoric acid present, place the stoppered flask containing the solution in a shaking apparatus and shake for 30 minutes at room temperature, filter at once, wash, and titrate as in (a). 4 METHODS OF ANALYSIS [Chap. WATER-SOLUBLE PHOSPHORIC ACID. 10 Gravimelric Method. — Official. Place 2 grams of the sample on a 9 cm. filter, wash with successive small portions of water, allowing each portion to pass through before adding more, until the filtrate measures about 250 cc. If the filtrate is turbid, add a little nitric acid. Make up to any convenient volume, mix well, use an aliquot, and proceed as under 6. 1 1 Volumetric Method. — Official. Treat the sample as directed under 10. To an aliquot of the solution cor- responding to 0.2 or 0.4 gram, add 10 cc. of concentrated nitric acid and ammonium hydroxid until a slight permanent precipitate is formed, dilute to 60 cc, and pro- ceed as directed under 9. CITRATE-INSOLUBLE PHOSPHORIC ACID.— OFFICIAL. 12 REAGENTS. In addition to the reagents given under 4 and 7 prepare ammonium citrate solu- tion by one of the following methods: Ammonium citrate solution. — (1) Dissolve 370 grams of commercial citric acid in 1500 cc. of water; nearly neutralize with commercial ammonium hydroxid; cool; add ammonium hydroxid until exactly neutral (testing with litmus or azolitmin paper), and dilute sufficiently to make the specific gravity 1.09 at 20°C. The vol- ume will be about 2 liters;- or, (2) To 370 grams of commercial citric acid add commercial ammonium hydroxid until nearly neutral; reduce the specific gravity to slightly more than 1.09 at 20°C. and make exactly neutral, testing as follows: Prepare a solution of fused calcium chlorid, 200 grams to the liter, and add 4 volumes of strong alcohol. Make this solution exactly neutral, using a small amount of freshly prepared corallin solution as preliminary indicator, and test finally by withdrawing a portion, diluting with an equal volume of water, and testing with cochineal solution; 50 cc. of this solution will precipitate the citric acid from 10 cc. of the citrate solution. To 10 cc. of the nearly neutral citrate solution add 50 cc. of the alcoholic calcium chlorid solution, stir well, filter at once through a folded filter, dilute with an equal volume of water, and test the reaction with neutral solution of cochineal. If acid or alkaline, add ammonium hydroxid or citric acid, as the case may be, to the citrate solution, mix, and test again, as before. Repeat this process until a neutral reaction is obtained. Add sufficient water to make the specific gravity 1.09 at 20°C. 13 DETERMINATION. (a) Acidulated samples. — Heat 100 cc. of strictly neutral ammonium citrate solution (sp. gr. 1.09) to 65°C. in a 250 cc. Erlenmeyer flask placed in a warm water bath, keeping the flask loosely stoppered to prevent evaporation. The level of the water in the bath should be above that of the citrate solution in the flask. When the citrate solution has reached 65°C., drop into it the filter containing the washed residue from the water-soluble phosphoric acid solution in 1 0, close tightly with a smooth rubber stopper, and shake violently until the filter paper is reduced to a pulp, relieving the pressure by momentarily removing the stopper. Place the flask in the bath and maintain its contents at exactly 65°C. Shake the flask every 5 minutes. At the expiration of exactly 30 minutes from the time the filter and the residue are introduced, remove the flask from the bath and immediately filter the contents as rapidly as possible through a quick-acting filter paper. Wash with I] FERTILIZERS 5 water at 65°C. until the volume of the filtrate is about 350 cc, allowing time for thorough draining before adding new portions of water. (1) Transfer the filter and its contents to a crucible, ignite until all organic matter is destroyed, add 10- 15 cc. of strong hydrochloric acid, and digest until all phosphate is dissolved; or, (2) Return the filter with contents to the digestion flask, add 30-35 cc. of strong nitric acid, 5-10 cc. of strong hydrochloric acid, and boil until all phosphate is dis- solved. Dilute the solution as prepared in (1) or (2) to 200 cc. If desired, the filter and its contents may be treated according to methods 5 (b), (C) or (d). Mix well, filter through a dry filter and proceed as directed under 6 or 9. (b) Non-acidulated samples. — In case a determination of citrate-insoluble phos- phoric acid is required in non-acidulat«d samples treat 2 grams of the phosphatic material without previous washing with water, precisely as in (a), except when the substance contains much animal matter (bone, fish, etc.), in which case dissolve the residue insoluble in ammonium citrate by any one of the processes described under 5 (b), (C) or (d) and determine phosphoric acid as directed in 6 or 9. 14 CITRATE-SOLUBLE PHOSPHORIC ACID.— OFFICL&L. The sum of the water-soluble and citrate-insoluble subtracted from the total gives the citrate-soluble phosphoric acid. 15 DETECTION OF NITRATES.— OFFICIAL. Mix 5 grams of the fertilizer with 25 cc. of hot water and filter. To a portion of this solution add 2 volumes of concentrated sulphuric acid, free from nitric acid and oxids of nitrogen, and allow the mixture to cool. Add cautiously a few drops of a concentrated solution of ferrous sulphate so that the fluids do not mix. If nitrates are present the junction shows at first a purple, afterwards a brown, color or if only a very minute quantity be present, a reddish color. To another portion of the solu- tion add 1 cc. of a 1% solution of sodium nitrate and test as before to determine whether sufficient sulphuric acid were added in the first test. ORGANIC AND AMMONIACAL NITROGEN ONLY. Kjddahl Method.— Official. 1 6 REAGENTS. For ordinary work N/2 acid is recommended. For work in determining very small amounts of nitrogen N/10 acid is recommended. In titrating mineral acids against ammonium hydroxid solution use cochineal or methyl red as indicator. (a) Standard hydrochloric acid. — Determine the absolute strength as follows: Preliminarij test. — Place a measured portion of the acid to be standardized in an Erlenmeyer flask with excess of calcium carbonate, to neutralize free acid, and a few drops of potassium chromate as indicator. By titration with silver nitrate solution determine exactly the quantity required to precipitate the chlorin. Final determination. — To a measured portion of the acid to be standardized add from the burette 1 drop in excess of the required quantity of silver nitrate solution as deter- mined by the preceding test. Heat to boiling, protect from the light, and allow to stand until the precipitate is granular. Filter on a tared Gooch crucible, previously heated to 140°-150°C.. wash with hot water, testing the filtrate to prove excess of silver nitrate. Dry the silver chlorid at 140°-150°C., cool and weigh. (b) Standard sulphuric oczcZ.— Determine the absolute strength of the acid by precipitation with barium chlorid solution as follows: Dilute a measured quantity of the acid to be standardized to approximately 100 cc, heat to boiling and add drop 6 METHODS OF ANALYSIS [Chap. by drop a 10 % solution of barium chlorid until no further jjrccii^itation occurs. Continue the boiling for about 5 minutes, allow to stand for 5 hours or longer in a warm place, pour the supernatant liquid on a tared Gooch or on an ashless filter, treat the precipitate with 25-30 cc. of boiling water, transfer to the filter and wash with boiling water until the filtrate is free from chlorin. Dry, ignite over a Bunsen burner and weigh as barium sulphate. (C) Standard alkali solution. — Accurately determine the strength of this solution by titration against the standard acid. N/10 solution is recommended. (d) Sulphuric acid. — Sp. gr. 1.84 and free from nitrates and ammonium sulphate. (e) Metallic mercury, or mercuric oxid. — Mercuric oxid should be prepared in the wet way, but not from mercuric nitrate. (f) Copper sulphate. — Crystallized. (^) Potassium permanganate. — Finely pulverized. (h) Granulated zinc or pumice stone. — Added to the contents of the distillation flask if necessary to prevent bumping. (i) Potassium sulphid solution. — Dissolve 40 grams of commercial potassium sulphid in 1 liter of water. (j ) Sodium hydroxid solution. — A saturated solution, free from nitrates. (k) Cochineal solution. — Digest, with frequent agitation, 3 grams of pulverized cochineal in a mixture of 50 cc. of strong alcohol and 200 cc. of water for 1 or 2 days at ordinary temperature, and then filter. (1) Methyl red solution. — Dissolve 1 gram of methyl red (dimethyl-amino-azo- benzene-ortho-carbonic acid) in 100 cc. of 95% alcohol. 17 APPARATUS. (a) Kjeldahl flasks for both digestion and distillation. — Total capacity of about 550 cc, made of hard, moderately thick, and well-annealed glass. (b) Distillation flasks. — For distillation any suitable flask of about 550 cc. capac- ity may be used. It is fitted with a rubber stopper through which passes the lower end of a Kjeldahl connecting bulb to prevent sodium hydroxid being carried over mechanically during distillation. The bulb should be about 3 cm. in diameter, and the tubes should be of the same diameter as the condenser tube with which the upper end of the bulb tube is connected by means of rubber tubing. 1 8 DETERMINATION. Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be analyzed in a digestion flask with approximately 0.7 gram of mercuric oxid, or its equivalent in metallic mercury, and add 20-30 cc. of sulphuric acid (0.1-0.3 gram of crj'stallized copper sulphate may also be used in addition to the mercur}-, or in place of it). Place the flask in an inclined position and heat below the boiling point of the acid until frothing has ceased. (A small piece of paraffin may be added to prevent extreme foaming.) Then raise the heat until the acid boils briskly and digest for a time after the mixture is colorless or nearly so, or until oxidation is complete. Remove the flask from the flame, hold it upright, and while still hot add care- fully potassium permanganate in small quantities at a time until, after shaking, the liquid remains green or purple. After cooling dilute with about 200 cc. of water, add a few pieces of granulated zinc or pumice stone, if necessary to prevent bumping, and 25 cc. of potassium sul- phid solution with shaking. Next add sufficient sodium hj^droxid solution to make the reaction strongly alkaline, 50 cc. are usually enough, pouring it down the side of the flask so that it does not mix at once with the acid solution. Connect the flask IJ FERTILIZERS with the condenser, mix the contents by shaking, distil until all ammonia has over into a measured quantity of the standard acid and titrate with the standard alkali. The first 150 cc. of the distillate will generally contain all the ammonia. The use of mercuric oxid in this operation greatly shortens the time necessary for digestion, which is rarely over an hour and a half in case of substances most difficult to oxidize, and is more commonly less than an hour. In most instances the use of potassium permanganate is quite unnecessary, but it is believed that in exceptional cases it is required for complete oxidation, and in view of the uncer- tainty it is always used. The potassium sulphid removes all the mercurj"- from the solution, and so prevents the formation of mercuro-ammoniura compounds which are not completely decomposed by the sodium hydroxid. The addition of zinc gives rise to an evolution of hydrogen and prevents violent bumping. Previous to use the reagents should be tested by a blank experiment with sugar. The sugar partially reduces any nitrates present that might otherwise escape notice. Gunning Method. — Official. 19 REAGENTS. Potassium sulphate. — Pulverized. The other reagents and standard solutions used are described under 16. 20 APPARATUS. The apparatus used is described under 17. 21 DETERMINATION. Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be analyzed in a digestion flask. Add 10 grams of powdered potassium sulphate and 15-25 cc. (ordinarily about 20 cc.) of sulphuric acid (0.1-0.3 gram of crystallized copper sulphate may also be added). Conduct the digestion as in the Kjeldahl process, starting with a temperature below the boiling point and increasing the heat gradually until frothing ceases. Digest for a time after the mixture is colorless or nearly so, or until oxidation is complete. Do not add either potassium permanganate or potassium sulphid. Cool, dilute, neutralize, distil, and titrate with the standard alkali. In neutralizing before distilling it is convenient to add a few drops of phenolphthalein indicator or litmus paper. The pink color given by phenolphthal- ein indicating an alkaline reaction is destroj-ed by a considerable excess of strong fixed alkali. Kjeldahl-Gunning -Arnold Method. — Official. 22 REAGENTS AND APPARATUS. Described under 16, 17 and 19. DETERMINATION. 23 Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be analyzed in a digestion flask. Add 15-18 grams of potassium sulphate, 1 gram of copper sulphate, 1 gram of mercuric oxid, or its equivalent in metallic mercury, and 25 cc. of sulphuric acid. Heat gently until frothing ceases, then boil the mixture briskly, and continue the digestion for a time after the mixture is colorless or nearly so or until oxidation is complete. Cool, dilute with about 200 cc. of water, add 50 cc. of potassium sulphid sqlution, make strongly alkaline with sodium hydroxid solu- tion and complete the determination as directed under 18. 8 METHODS OF ANALYSIS [Chap. TOTAL NITROGEN. Kjeldahl Method Modified to include the Nitrogen of Nitrates. — Official. 24 REAGENTS. (a) Zinc dust. — Impalpable powder. Granulated zinc or zinc filings will not answer. (b) Sodiu7n thiosulphate. (C) Commercial salicylic acid. The other reagents and standard solutions are described under 16. 25 APPARATUS. The apparatus used is described under 1 7. 26 DETERMINATION. Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be analyzed in a Kjeldahl digestion flask. (1) Add 30 cc. of sulphuric acid containing 1 gram of salicylic acid, shake until thoroughly mi.xed, allow to stand for at least .30 minutes, and then add 5 grams of crystallized sodium thiosulphate and digest as directed below; or, (2) Add to the substance 30 cc. of sulphuric acid containing 2 grams of salicylic acid, allow to stand at least 30 minutes and then add gradually 2 grams of zinc dust, shaking the contents of the flask at the same time and digest as follows: Place the flask on the stand for holding the digestion flasks and heat over a low flame until all danger from frothing has passed. Then raise the heat until the acid boils briskly and continue the boiling until white fumes no longer escape from the flask. This requires about 5-10 minutes. Add approximately 0.7 gram of mercuric oxid, or its equivalent in metallic mercury, and continue the boiling until the liquid in the flask is colorless, or nearly so. In case the contents of the flask are likely to become solid before this point is reached, add 10 cc. more of sulphuric acid. Complete the oxidation with a little potassium permanganate in the usual way and proceed as directed under 18. The reagents should be tested by blank experiments. Gunning Method Modified to include the Nitrogen of Nitrates. — Official. 27 REAGENTS AND APPARATUS. The reagents and standard solutions are described under 16, 17, 19 and 24. 28 DETERMINATION. Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be analj^zed in a digestion flask. Add 30-35 cc. of salicylic acid mixture (30 cc. of sul- phuric acid to 1 gram of salicylic acid) ; shake until thoroughly mixed, and allow to stand for at least 30 minutes with frequent shaking. Add 5 grams of sodium thio- sulphate and heat the solution for 5 minutes; cool; add 10 grams of potassium sulphate and heat very gently until foaming ceases, then strongly until nearly colorless, and proceed as directed under 21 . Absolute or Cupric Oxid Method. — Official. 29 REAGENTS. (a) Coarse cupric oxid. — Ignite and cool before using. (b) Fine cupric oxid. — Grind (a). FERTILIZERS 9 (C) Metallic copper.— Granulated copper, or fine copper gauze, heated and cooled in a current of hydrogen or by dropping the heated copper into a test tube containing a few cc. of methyl alcohol. (d) Sodium hicarhonate. — Free from organic matter. (e) Caustic potash solution. — A supersaturated solution of caustic potash in hot water. 30 APPARATUS. (a) Combustion tube. — Hard Bohemian glass, about 65 cm. long, 12.7 mm. internal diameter and sealed at one end. (b) Azotometer. — Capacity 100 cc, accurately calibrated. (C) Sprengel mercury air pump. (d) Small paper scoop. — Made from stiff writing paper. 31 DETERMINATION. Use 1-2 grams of ordinary commercial fertilizers. In the case of highly nitrogen- ized substances, the amount to be used is governed by the amount of nitrogen esti- mated to be present. Fill the tube (Fig. 1) as follows: (1) about 5 cm. of coarse y/. ^SiE n^ I \E \m sg8ffl®®»3SgS8Bas&a@{^^^sg(ss >LJLiiJ 5 CM. 10 CM. CQAR5E SUBSTANCe OX IV. ANO firiE onto. T CM. 6 cn MSTAUic capiat COPPER. OMD. 2.5 cn FRSE e NO- SODIUM BICARBONATB. THE ROMAN NUMERALS REFER TO THE ORDER IN WHICH THE DIFFERENT PORTIONS ARE TO BE HEATED. cupric oxid; (2) place on the small paper scoop a sufficient amount of the fine cupric oxid which, when mixed with the substance to be analyzed, will fill about 10 cm. of the tube; pour on this the substance, rinsing the watch glass with a little of the fine oxid, and mix thoroughly with a spatula, pour into the tube, rinsing the scoop with a little fine oxid; (3) about 30 cm. of coarse cupric oxid; (4) about 7 cm. of metallic copper; (5) about 6 cm. of coarse cupric oxid; (6) a small plug of asbestos; (7) 0.8-1 gram of sodium bicarbonate; (8) a large loose plug of asbestos. After the tube is filled hold in a horizontal position and tap gently on the table in order that a canal may be formed in the upper portion of the fine cupric oxid. Place the tube in the combustion furnace, leave about 2.5 cm. of it projecting and connect with the pump by a rubber stopper smeared with glycerol, taking care to make the connection perfectly tight. In order to protect the latter from the heat, place an asbestos plate, having a circular opening in the center, over the projecting end of the tube. Exhaust the air from the tube by means of the pump. When a vacuum has been obtained, allow the flow of mercury to continue; light the gas under that part of the 10 METHODS OF ANALYSIS [Chap. tube containing the metallic copper, the anterior layer of cupric oxid and the sodium bicarbonate. As soon as the vacuum is destroyed and he apparatus filled w th carbon dioxid, shut off the flow of mercury and at once introduce the delivery tube of the pump into the receiving arm of the azotometer just below the surface of the mercury seal so that the escaping bubbles will pass into the air and not into the tube, to avoid the useless saturation of the caustic potash solution. When the flow of carbon dioxid has very nearly or completely ceased, pass the delivery tube down into the receiving arm so that the bubbles will escape into the azotometer. Light the gas under the 30 cm. layer of oxid, heat gently for a few minutes, to drive out anj^ moisture that may be present, and then bring to a red heat. Heat gradually the mixture of substance and oxid, lighting a jet at a time. Avoid a too rapid evolution of bubbles, which should be allowed to escape at the rate of about one per second or a little faster. When the burners under the mixture have all been turned on, light the gas under the layer of oxid at the end of the tube. When the evolution of bubbles has ceased, turn out all the burners except those under the metallic copper and anterior layer of oxid, and allow to cool for a few min- utes. Exhaust with the pump and remove the azotometer before the flow of mercury has stopped. Break the connection of the tube with the pump, stop the flow of mercury, and extinguish the burners. Allow the azotometer to stand for at least an hour, or cool with a stream of water until the volume and temperature become constant. Adjust accurately the level of the potassium hydroxid solution in the bulb to that in the azotometer; note the volume of the nitrogen, temperature, and height of barometer; calculate the weight of the nitrogen as usual. AMMONIACAL NITROGEN. 32 Magnesium Oxid Method. — Official. Place 0.7-3.5 grams, according to the ammonia content, of the substance to be analj'zed in a distillation flask with about 200 cc. of water and 5 grams or more of magnesium oxid, free from carbonates. Then connect the flask with a condenser and distil 100 cc. of the liquid into a measured quantity of standard acid and titrate with standard alkali solution. NITRIC AND AMMONIACAL NITROGEN. 33 Ulsch-Slreet Method.— Official. Place 1 gram of the sample in a half-liter flask, add about 30 cc. of water and 2-3 grams of reduced iron, and, after standing sufficiently long to insure solution of the soluble nitrates and ammonium salts, add 10 cc. of a mixture of strong sulphuric acid with an equal volume of water; shake thoroughl}', place a long-stemmed funnel in the neck of the flask to prevent mechanical loss, and allow to stand for a short time until the violence of the reaction has moderated. Heat the solution slowly, boil for 5 minutes, and cool. Add about 100 cc. of water, a little paraffin, and 7-10 grams of magnesium oxid, free or nearly free from carbonates. Connect with a condenser, such as is used in the Kjeldahl method, and boil the mixture for 40 minutes, nearly to dryness; collect the ammonia in a measured quantity of standard acid, and titrate with standard alkali solution in the usual manner. The nitrogen obtained represents the nitrates plus the ammonium salts contained in the sample. In the analysis of nitrate salts proceed as above, except that 25 cc. of the nitrate solution, equivalent to 0.25 gram of the sample, are emplo3^ed with 5 grams of re- duced iron. After boiling add 75 cc. of water and an excess of sodium hydroxid solution and complete the determination as above. I] FERTILIZERS 11 34 Zinc-Iron Method. — Official. Dissolve 10 grams of the sample in water and dilute to 500 cc. Place 25 cc. of this solution, corresponding to 0.5 gram of the substance, in a 400 cc. distillation flask, add 120 cc. of water, 5 grams of well-washed and dried zinc dust, and 5 grams of reduced iron. To the solution add 80 cc. of saturated sodium hydroxid solution, connect the flask with the condensing apparatus and conduct the distillation .simul- taneously with the reduction, collecting the ammonia in standard acid. Continue the distillation until 100 cc. have been distilled and titrate with standard alkali solution. NITROGEN IN NITRATE SALTS. 35 Ferrous Sulphate-Zinc-Soda Method. — Tentative. Place 0.5 gram of the nitrate salt in a 600-700 cc. flask, add 200 cc. of water, 5 grams of powdered zinc, 1-2 grams of ferrous sulphate, and 50 cc. of sodium hy- droxid solution (36° Baume). Connect with the distilling apparatus, distil, collect the distillate in the usual way in N/10 sulphuric acid and titrate with standard alkali solution. ORGANIC NITROGEN SOLUBLE IN NEUTRAL PERMANGANATE.— OFFICIAL. 36 Preliminary Test {Determination of Water-Insoluble Organic Nitrogen). Place 1 gram of the material on an 11 cm. filter paper and wash with water at room temperature until the filtrate measures 250 cc. Dry and determine nitrogen in the residue, as in 18 or 21, making a correction for the nitrogen of the filter, if necessary. 37 DETERMINATION. Place a quantity of the fertilizer, equivalent to 50 mg. of water-insoluble organic nitrogen as determined in 36, on a moistened 11 cm. filter paper and wash with water at room temperature until the filtrate measures 250 cc. Transfer the insoluble residue with 25 cc. of tepid water to a 300 cc. Griffin low-form beaker, add 1 gram of sodium carbonate, mix, and add 100 cc. of 2% permanganate. Cover with a watch glass and immerse for 30 minutes in a steam or hot water bath so that the level of the liquid in the beaker is below that of the water in the bath. Stir twice at inter- vals of 10 minutes. At the end of the digestion remove from the bath, add immedi- ately 100 cc. of cold water, and filter through a heavy 15 cm. folded filter. Wash with small quantities of cold water until the filtrate measures about 400 cc. De- termine nitrogen in the residue and filter, as in 18 or 21, correcting for the nitrogen contained in the latter. The nitrogen thus obtained is the inactive water-insoluble organic nitrogen. Subtract this result from that obtained in 36 to obtain the percentage of organic nitrogen soluble in neutral permanganate. ORGANIC NITROGEN SOLUBLE IN ALKALINE PERMANGANATE.— OFFICIAL. (Not applicable to fertilizers containing cottonseed meal or castor pomace.) 38 PREPARATION OF SAMPLE. (a) Mixed fertilizers. — Place an amount of material, equivalent to 50 mg. of water- insoluble organic nitrogen determined as directed under 36, on a filter paper and wash with water at room temperature until the filtrate measures 250 cc. 12 METHODS OF ANALYSIS (Chap. (b) Raw materials. — Place an amount of material, equivalent to 50 mg. of water- insoluble organic nitrogen determined as directed under 36, in a small mortar, add about 2 grams of powdered rock phosphate, mix thoroughly, transfer to a filter paper, and wash with water at room temperature until the filtrate measures 250 cc. When much oil or fat is present, it is well to wash with ether before extracting with water. 39 DETERMINATION. Dry the residue of 38 at a temperature not exceeding 80°C. and transfer from the filter to a 500-600 cc. Kjeldahl distillation flask. Add 20 cc. of water, 15-20 small glass beads, or fragments of pumice stone, a piece of paraffin the size of a pea, and 100 cc. of alkaline permanganate solution (25 grams of pure potassium permanganate and 150 grams of sodium hydroxid, separately dissolved in water, the solutions cooled, mixed, and made to a volume of 1 liter). Connect with an upright condenser to the lower end of which a receiver containing standard acid has been attached. Digest slowly, for at least 30 minutes, below distillation point, with a very low flame, using coarse wire gauze and asbestos paper between the flask and flame. Gradually raise the temperature and, after any danger from frothing has passed, distil until 95 cc. of the distillate are obtained, and titrate as usual. When a tendency to froth is noticed, lengthen the digestion period and no trouble will be experienced when the distillation is begun. During the digestion gently rotate the flask occasionally, particularly if the material shows a tendency to adhere to the sides. The nitrogen thus obtained is the active water-insoluble organic nitrogen. Method I. Lindo-Gladding Method. — Official. 40 REAGENTS. (a) Ammonium chlorid solution. — Dissolve 100 grams of ammonium chlorid in 500 cc. of water, add 5-10 grams of pulverized potassium-platinic chlorid, and shake at intervals for 6-8 hours. Allow the mixture to settle overnight and filter. The residue may be used for the preparation of a fresh supply. (b) Platinum solution.— A. platinic chlorid solution containing the equivalent of 1 gram of metallic platinum (2.1 grams of H2PtCl6) in every 10 cc. (C) 80% alcohol.— Sp. gr. 0.8645 at -^^. Denatured alcohol, made up according to formula 1 (U. S. Internal Rev., Reg. No. 30, Revised, Aug. 22, 1911, p. 45) and di- luted with water to make 80% alcohol by volume, may also be used. 41 PREPARATION OP SOLUTION. (a) Mixed fertilizers.— Tlace 2.5 grams of the sample upon a 12.5 cm. filter paper and wash with boiling water until the filtrate amounts to about 200 cc. Add to the filtrate 2 cc. of concentrated hydrochloric acid, heat to boiling, transfer to a 250 cc. graduated flask and add to the hot solution a slight excess of ammonium hj-droxid and sufficient ammonium oxalate to precipitate all the lime present, cool, dilute to 250 cc, mix, and pass through a dry filter. (b) Potash salts; jnuriate and sulphate of potash, sulphate of potash and magnesia, and kainit. — Dissolve 2.5 grams and dilute to 250 cc. without the addition of am- monium hydroxid and ammonium oxalate. (C) Organic compounds.— W^hen it is desired to determine the total amount of potash in organic substances, such as cottonseed meal, tobacco stems, etc., saturate I] FERTILIZERS 13 10 grams of the sample with strong sulphuric acid and ignite in a muffle at a low red heat to destroy organic matter. Add a little strong hydrochloric acid, warm slightly in order to loosen the mass rom the dish, transfer to a 250 cc. graduated flask, add ammonia and ammonium oxalate and proceed as in (a). 42 DETERMINATION. (a) Mixed fertilizers. — Evaporate 50 cc. of the solution in 41 (a) nearly to dryness, add 1 cc. of dilute sulphuric acid (1 to 1), evaporate to dryness, and ignite to white- ness. Maintain a full red heat until the residue is perfectly white. Dissolve the residue in hot water, using at least 20 cc. for each decigram of potassium oxid pres- ent, add a few drops of hydrochloric acid, and platinum solution in excess. Evap- orate on a water bath to a thick paste. Treat the residue with 80% alcohol, avoid- ing exposure to ammonia. Filter, wash the precipitate thoroughly with 80% alco- hol both by decantation and on the filter, continuing the washing after the filtrate is colorless. Then wash with 10 cc. of the ammonium chlorid solution to remove impurities from the precipitate and repeat 5 or 6 times. Wash again thoroughly with 80% alcohol and dry the precipitate for 30 minutes at lOO'C. Weigh and cal- culate to potassium oxid. The precipitate should be perfectly soluble in water. (b) Muriate of potash. — Acidify 50 cc. of the solution prepared according to 41 (b) with a few drops of hydrochloric acid, add 10 cc. of platinum solution and evapo- rate to a thick paste. Treat the residue as under (a). (C) Sulphate of potash; sulphate of potash and magnesia; andkainit. — Acidify 50 cc. of the solution prepared according to 41 (b) with a few drops of hydrochloric acid and add 15 cc. of platinum solution. Evaporate the mixture and proceed as directed under (a), except that 25 cc. portions of the ammonium chlorid solution should be used. (d) Water-soluble potash in wood ashes and cotton hull ashes. — Prepare the solution according to 41 (a) and proceed as directed under (a), paying special attention to the last sentence. Method II.— Official. (The Lindo-Gladding method is preferable in the presence of soluble sulphates.) 43 REAGENTS. Described under 40. 44 PREPARATION OF SOLUTION. Prepare the solution as directed under 41, omitting in all cases the addition of ammonium hydroxid and ammonium oxalate. DETERMINATION. 45 Dilute 25 cc. of the solution made as directed under 44 (50 cc. if less than 10% of potassium oxid be present) to 150 cc, heat to 100°C., and add, drop by drop, with constant stirring, a slight excess of barium chlorid solution. Without filtering, add in the same manner barium hydroxid solution in slight excess. Filter while hot and wash until the precipitate is free from chlorin. Add to the filtrate 1 cc. of strong ammonium hydroxid, and then a saturated solution of ammonium carbonate until the excess of barium is precipitated. Heat and add, in fine powder, 0.5 gram of pure oxalic acid or 0.75 gram of ammonium oxalate. Filter, wash free from chlorin, evaporate the filtrate to di'yness in a platinum dish, and ignite carefully over the free 14 METHODS OF ANALYSIS [Chap. flame, below a red heat, until all volatile matter is driven off. Digest the residue with hot water, filter through a small filter and dilute the filtrate, if necessary, so that for each decigram of potassium oxid there will be at least 20 cc. of liquid. Acid- ify with a few drops of hydrochloric acid and add platinum solution in excess. Evap- orate on a water bath to a thick paste and treat the residue with 80% alcohol, both by decantation and after collecting on a Gooch or other form of filter, dry for 30 minutes at 100°C. and weigh. If there is an appearance of foreign matter in the double salt, it should be washed as in 42 (a) with several portions of 10 cc. each of the ammonium chlorid solution. THOMAS OR BASIC SLAG.— TENTATIVE. 46 MECHANICAL ANALYSIS. Proceed as directed under 1, using 10 grams of material. 47 PREPARATION OF SAMPLE. Prepare the sample as directed under 2. TOTAL PHOSPHORIC ACID. Gravimetric Method. 48 PREPARATION OF SOLUTION. Prepare the solution for analysis as directed under 5 (C), or in strong hydrochloric acid alone. In the latter case after the portion for analysis is measured out, add nitric acid and heat for a few minutes. 49 DETERMINATION. Dehydrate an aliquot (20 cc.) of 48 by evaporating to dryness on a steam or hot water bath; treat with 5 cc. of hydrochloric acid and 25 cc. of hot water; digest in order to complete solution and filter off silica. From this point proceed as directed under 6. Before precipitating with magnesia mixture, add 5 cc. of 5% sodium acetate. 50 Volumetric Method. Prepare the solution as directed under 5 (C) and determine the phosphoric acid in an aliquot of this solution as directed under 9, standardizing the solutions against a standard phosphate material of approximately the same composition as the sample under examination. CITRATE-SOLUBLE PHOSPHORIC ACID. Gravimetric Method. — {Wagner's Method.) 51 PREPARATION OF SOLUTION. Weigh 5 grams of the slag into a 500 cc. Wagner flask containing 5 cc. of 95% alcohol. (The flask should have a neck width of at least 22 mm. and should be marked at least S cm. below the mouth.) Make up to the mark with 2% citric acid solution of a temperature of 17.5°C. Fit the flask with a rubber stopper and place at once in a rotary apparatus, shaking the flask for 30 minutes at the rate of 30-40 revolutions per minute, at the end of which time remove the flask, filter immediately on a dry filter and analyze the solution at once. I] FERTILIZERS 16 52 DETERMINATION. To 50 cc. of the clear filtrate in a beaker add 100 cc. of molybdate solution prepared as directed under 4 (a). Place the beaker in a water bath, until the temperature of the beaker's contents reaches 65 °C., remove from the bath and cool to room tem- perature. Filter and wash the yellow precipitate of ammonium phosphomolybdate 4 or 5 times with 1% nitric acid. Dissolve the precipitate in 100 cc. of cold 2% ammonium hydroxid, nearly neutralize with hydrochloric acid and add to the solu- tion, drop by drop, with continuous stirring, 15 cc. of magnesia mixture prepared as directed under 4 (C) and proceed as under 6. 53 Volumetric Method. In an aliquot of the clear solution prepared as in 51, determine the phosphoric acid as directed under 9. II. SOILS. 1 DIRECTIONS FOR TAKING SAMPLES.— OFFICIAL. Sampling should be done preferably when the soil is reasonably dry. Remove from the surface all vegetable material not incorporated with the soil. With a soil auger or tube, whichever may be better adapted to the soil conditions, take a sufficient number of sub-samples at properly distributed points to secure composite samples representative of the entire tract. (a) Surface soil. — Take a composite sample representative of the entire tract to a depth of either (1) 6 inches, (2) the average depth of the plowed soil if this ex- ceeds G inches, or (3) a maximum depth of 12 inches when there is no clear line of demarcation between the soil and sub-soil above this depth. (b) Siih-soil.— Take a composite sample of each important and distinctly different soil stratum below the surface section already sampled to a total depth of 40 inches. If a soil auger is used, before taking sub-soil samples the hole should be enlarged and carefully cleaned out with the auger to prevent contamination of the several substrata when the sample is being withdrawn. Mix each composite sample thoroughly and, after cutting down by quartering to about 2-4 pounds, air-dry in a cool, well-ventilated place. It is recommended that the weight of a given volume of the soil as it lies in the field be taken for calculating the percentage results obtained by analysis to pounds per given area of the soil. 2 PREPARATION OF SAMPLE. -OFFICIAL. After air-drying and weighing the sample, pulverize in a porcelain mortar, using a rubber-tipped pestle to avoid the reduction of rock fragments, and pass through a sieve with circular openings 1/25 inch (1 mm.) in diameter. Discard the detritus and weigh. Thoroughly mix the sifted material and preserve in a suitable stoppered container. For the quantitative determination of any of the constituents, prepare a very finely pulverized sub-sample of the sifted material, using an agate mortar. 3 MOISTURE.— OFFICIAL. Dry 2 or more grams of the sample, as prepared under 2, in a tared platinum dish for 5 hours at the temperature of boiling water; cover the dish, cool in a desiccator, and weigh rapidly to prevent the absorption of moisture. Heat, cool, and weigh at intervals of 2 hours to constant weight. The loss of weight is reported as moisture. 4 VOLATILE MATTER.-OFFICIAL. Heat the dish and dry soil from 3 to full redness, stirring occasionally, until all or- ganic matter is destro3'ed. If the soil contains appreciable quantities of carbonates, cool and moisten with a few drops of saturated ammonium carbonate solution, dry and heat to dull redness to, expel ammonium salts; cool in a desiccator and weigh. 17 18 METHODS OF ANALYSIS [Chap. ORGANIC CARBON.— OFFICIAL. APPARATUS. (a) A calorimeter bomb. — Use a type that permits the recovery and transfer of the entire solid residue of the exploded charge to a small vessel by means of a jet of water. (b) Parr's apparatus for determining carbon dioxide — Illustrated in Fig. 2. FIG, 2. PARR'S APPARATUS FOR THE DETERMINATION OF CARBON DIOXID. This consists of a 150 cc. Erlenmeyer flask {F) fitted with a 3-holed stopper through 2 of which the stems of 2 dropping funnels {S) and {A) extend almost to the bottom of the flask. A capillary tube, passing through the third hole and flush with the bottom of the stopper, connects with the gas burette {B). (C) A simple Hemple gas pipette. — Contains S0% potassium hydroxid solution. 6 DETERMIXATIOX. Introduce 2 grams of soil as prepared under 2 (1 gram if high in organic matter), 0.75 gram of magnesium powder, and 10 grams of sodium peroxid, into the closed dry calorimeter bomb, and mix thoroughly by shaking the bomb back and forth. Explode the charge by means of an electric spark or by dropping a red hot plug into the bomb through an automatic valve which closes immediately after the plug enters. Remove the residue from the bomb, using as little hot water as possible, heat to boiling, and transfer to the receiving funnel (S) of Parr's apparatus. From the acid funnel (A) run 50 cc. of sulphuric acid (1 to 2) into the flask (F). Connect the apparatus and slowly add the contents from the receiving funnel (S). The carbon dioxid gener- ated passes through the capillary tube into the graduated burette (B). Heat the contents of the flask (F) to boiling and boil for 1 minute, then force the gases into the graduated burette {B) by introducing water into the flask (F) through the fun- nel (S). Read the burette, recording the temperature and pressure. Pass the gas into an ordinary absorption pipette containing 30% potassium hydroxid solution. Shake the gas with the solution until carbon dioxid is wholly absorbed. Return the 11] SOILS 19 residual gas to the graduated burette (B), and again read the burette noting the temperature and pressure. The difference in readings calculated to standard con- ditions of temperature and pressure gives the number of cc. of carbon dioxid derived from the total carbon in the sample. Conduct a blank determination upon the reagents used. If an appreciable amount of carbon dio.xid is obtained in the blank, the result expressed in terms of total carbon must be corrected accordingly. Determine the inorganic carbon as directed under 9 and subtract it from the total carbon to obtain the organic carbon. INORGANIC CARBON. Modified Marr Methods — Tentative. 7 REAGENTS. (a) N/IO hydrochloric acid. (b) N/10 sodium hydroxid. (C) Dilute hydrochloric acid. — Dilute 25 cc. of concentrated hydrochloric acid (sp. gr. 1.19) to 250 cc. with carbon dioxid-free water. (d) Barium hydroxid solution. — Prepare a saturated aqueous solution of barium hydroxid, filter through asbestos into a large container through which air free from carbon dioxid has been aspirated for some time, and provide an arrangement whereby the solution may be delivered by air pressure or gravity and kept from contact with carbon dioxid by means of soda lime tubes. (e) Carbon dioxid-free water. — Use recently boiled and cooled water, or water from which carbon dioxid has been removed by aeration for a sufficient length of time with carbon dioxid-free air. Keep in a container provided with a similar attachment as in (d). 8 APPARATUS. HALF FULL OF BEADS OR . BROKEN GLASS 'iri ■Lfl FIG. 3. MODIFIED MARR APPAR^VTUS FOR DETERMINING CARBON DIOXID. The apparatus required (Fig. 3), consists of a tube {A), 50-60 cm. long, partly filled with beads or broken glass and containing strong potassium hydroxid solution (1 to 2), a cylindrical open top separatory funnel {B), capacity 50 cc, marked at 20 and 40 cc, the stem of which extends almost to the bottom of the 250 cc. fiask (C) into the 20 METHODS OF ANALYSIS I Chap. mouth of which is fitted, by means of a rubber stopper, a section of glass tubing 10 cm. in length and 1 cm. internal diameter, which in turn is furnished with a side tube extending through the condenser jacket (D), and connected by means of a rub- ber stopper to the small trap (K), which is attached to the Meyer absorption appara- tus (E) as shown in the figure. The Meyer absorption apparatus is provided with 2 large bulbs, each of about 250 cc. capacity, and 10 smaller connecting bulbs, each of about 10 cc. capacity. The connections between the various bulbs should have an internal diameter of 8-10 mm. A perforated rubber stopper carrying 2 short pieces of capillary tubing each provided with rubber tubing and pinch-cocks (N and 0) is fitted into the other opening of the Meyer absorption apparatus; (jY) is for the addition of reagents, (0) is connected to the vacuum pump. All parts of the apparatus must be capable of withstanding a vacuum of approxi- mately 70 cm. and be perfectly air tight. 9 DETERMINATION. Place 5-20 grams of soil as prepared under 2 (depending upon the carbonate con- tent as indicated by qualitative examination) in the flask (C), and connect up the apparatus, but do not connect {A) to (B). Close the stop-cock (G) and the pnch- cock (N) ; open the pinch-cock (0) and exhaust the apparatus to a vacuum of ap- proximately 70 cm. Close the pinch-cock (0). Connect the barium hydroxid container by means of the pinch-cock (A^ and rubber tube; open the pinch-co^k (N) and allow sufficient barium hydroxid solution to flow into the Meyer absorption apparatus to fill 3 or 4 of the small bulbs; close the pinch-cock (A''); substitute the barium hydroxid container by the carbon dioxid-free water container; open the pinch-cock (A'^) and add sufficient carbon dioxid-free water to fill all the small bulbs and most of the lower large bulb. Through the separatory funnel (S), add 80 cc. of carbon dioxid-free water to the sample in the flask (C), avoiding the entrance of any air, open the pinch-cock (0) and heat to boiling, protecting the flask from the direct fiame by a w^ire gauze with an asbestos center. Adjust the burner so that 2-3 min- utes are required for the contents of the flask to reach boiling temperature and boil until bubbles no longer pass through the Meyer absorption apparatus. Then close the pinch-cock (0), and run into the flask (C), avoiding the entrance of any air, 20 cc. of the dilute hydrochloric acid through the separatory funnel which is then connected with the tube {A). This proportion of hydrochloric acid plus the 80 cc. of water previously added, gives an acid (2 to 100) for the decomposition of carbonates. If the nature of the soil is such that a greater strength of acid is considered necessary, an amount of acid (3 to 100) may be used for digesting the soil. Shake the Meyer apparatus (E) gently, so that the liquid in the lower large bulb is brought into con- tact with the gas therein, and open (0) carefully, but do not allow- more than a few- bubbles to escape before shaking again. Repeat the operation several times until bubbles no longer pass through the Mej^er apparatus (E) when (0) is opened. Leave (0) open, and continue the boiling for about 25 minutes until carbon dioxid gas is no longer evolved from the sample in the flask (C). Maintain a constant flow of cold water through the condenser (D). Do not allow the boiling to become so violent that liquid is drawn up into the condenser tube. If foaming is troublesome, add a drop of non-volatile oil through the separatory funnel (B). When the evolution of carbon dioxid has ceased, close (0) and break the vacuum by cautiously opening the stop-cock (G) drawing in air through the tube (A). Disconnect the Mej^er apparatus (E) and filter by the Cain method^ as follows: Prepare a filter by covering a perforated porcelain plate within a carbon funnel with a layer of asbestos, and a laj'cr of ground quartz, both of which have previously been II] SOILS 21 purified by digestion with hj'drochloric acid and thorough washing with water. The filter tube passes through a 1-holed rubber stopper which fits into a side arm filtering flask. The side arm of this flask is connected to the suction pipe by a 2-way stop-cock. In the top of the filter tube is fitted a 2-hoIcd rubber stopper carrying glass tubes bent at right angles. To these tubes are attached rubber tubing bearing pinch-cocks. One of these rubber tubes terminates in a tube containing soda lime. The other rubber tube is connected with one end of the Meyer apparatus. The other end of the Meyer apparatus is attached to a bottle containing carbon dioxid-free water by means of a well-washed rubber tube and a glass tube extending to the bottom of the bottle. This glass tube passes through a 2-holed rubber stop- per. In the other hole of the stopper is placed a tube containing soda lime. A pinch-cock is placed on the tube joining the water bottle and the Meyer apparatus. This cock is kept closed until the precipitate on the filter is ready for washing. With the pinch-cock on the air outlet of the filter tube closed and the pinch-cock from the filter tube to the Meyer apparatus open, apply gentle suction to the filter flask until the contents of the Meyer apparatus have been transferred to the filter. When necessary, the pinch-cock to the air inlet of the filter tube is opened to admit air behind the liquid in the Meyer apparatus. Open the pinch-cock be- tween the wash-water bottle and the Meyer apparatus and open the stop-cock lead- ing from the filter flask so as to maintain a gentle suction. By manipulation of the Meyer apparatus the wash water comes in contact with all parts of the interior of the apparatus, after which the water is sucked through the filter. After this thorough washing admit air through the side opening of the stop-cock leading to the filter flask. Disconnect the apparatus, remove the filter pad with the barium carbonate from the filter tube by means of a glass rod, place in a beaker and add a measured amount of N/10 hydrochloric acid in excess, first rinsing the Meyer bulbs with a small amount, carefully measured, of this acid and water. Titrate the excess of acid with N/10 sodium hydroxid, using methyl orange as indicator. Make a blank determination under the same conditions and apply the necessary correction. From the amount of N/10 hydrochloric acid required to neutralize the barium carbonate formed by the carbon dioxid in the sample, calculate the quantity of inorganic carbon. One cc. of N/10 acid corresponds to 0.0006 gram of carbon. 10 TOTAL NITROGEN.— OFFICIAL. Place 7-14 grams of the soil, as prepared under 2, in a 300 cc. Kjeldahl digestion flask with 30 cc, or more if necessary, of concentrated sulphuric acid and 0.7 gram of mercuric oxid, or 0.65 gram of mercury. Mix immediately by shaking to prevent the soil from adhering to the sides of the flask. Heat over a low flame, increase the heat gradually, and rotate the flask frequently or shake if necessary to prevent the con- tents from sticking to the bottom of the flask. When all the organic matter is de- stroyed, continue the digestion for 1 hour. Oxidize the residue with potassium permanganate, carefully adding small portions at a time to the hot liquid until, after shaking, the liquid remains green or purple. After cooling, dilute the contents of the flask with 100 cc. of water and transfer to a 700 cc. copper flask, using about 150 cc. of water to wash out the digestion flask. Add an excess of strong alkali solution containing potassium sulphid, connect the flask with a distilling apparatus, mix the contents thoroughly and complete the determination as directed in I, 18. 22 METHODS OF ANALYSIS [Chap. Strong Acid Digestion of the Soil 1 1 preparation of soil solution.-official. Place aa amount of soil, as prepared under 2 and equivalent to 10 grams on a mois- ture-free basis, in a 200-300 cc. non-soluble glass Erlenmeyer flask to which is fitted, by a ground joint or 1-holed rubber stopper, a reflux tube 20 inches or more in length. Add lOOcc.of hydrochloric acid of constant boiling point (approximate sp. gr. 1.115, 1350 cc. of acid (sp. gr. 1.19), and 1000 cc. of water), and digest continuously for 10 hours on a steam or water bath, shaking the flask every hour. Allow to settle, and avoiding more than very small quantities of the sediment, decant the solution into a porcelain dish or non-soluble glass beaker. Transfer by means of hot water the insoluble residue to a filter, wash until free from chlorin and add the washings to the original solution. Concentrate, oxidize the organic matter present in the solution with a few drops of nitric acid and evaporate to dryness on a water bath. Treat with hot water, add a few cc. of hydrochloric acid and again evaporate to com- plete dryness. When the final evaporation is complete and the dish cooled, moisten the residue with a few drops of strong hydrochloric acid. Add 10-20 cc. of water, warm on the bath to secure complete solution of the soluble salts, filter and wash until free from chlorin. Again evaporate the solution to dryness to render insoluble any silica that may remain in solution, and treat as above. The filtrate constitutes the acid extract freed of soluble silica, and is made up to a definite volume (250 or 500 cc.) and designated as A. 1 2 INSOLUBLE RESIDUE.— OFFICIAL. Combine the filters and the main residue obtained in 11 in a small dish, dry, ignite over a Bunsen flame for an hour or more, carefully at first, then completely over a blast lamp to constant weight. Weigh and calculate as the insoluble residue. This residue may be analyzed by the usual methods applicable to silicates or it may be employed in the determination of total alkalies as described under 26. If it is desired to determine the silica soluble in alkalies, treat a separate portion of the soil as directed in 11, except that all filtrations must be made through the same hard- ened filter, then, without igniting, wash the insoluble residue into a platinum dish, dry at 100°C. and complete the determination as directed under III, 4 (a). 13 IRON, ALUMINnrM AND PHOSPHORIC ACID, COLLECTIVELY.— OFFICIAL. (l) To an aliquot (50 or 100 cc, according to the probable amount of iron present) of A, under 11, add ammonium hydroxid, drop by drop, until the precipi- tate formed requires several seconds to dissolve, thus leaving the solution but faint- ly acid. Heat nearly to the boiling point, and add ammonium hydroxid to precipi- tate all of the iron, aluminium, etc. Boil in a covered beaker for about 1 minute, remove, and if no ammonia is given off (detected by smelling) continue the addi- tion, drop by drop, until ammonia can be detected. Do not allow the precipitate to settle, but stir and pour on the filter. Wash immediately with hot water, using a fine jet which is played around the edge of the precipitate, thus cutting it free from the paper in order to produce rapid filtration. Wash the precipitate several times, return it to the original beaker, dissolve with a few drops of hydrochloric acid and warm. Reprecipitate the iron, aluminium and phosphoric acid with ammonium hydroxid as above and wash until free from chlorin. Designate the filtrate as B. Dry the filter and precipitate, remove the latter from the filter, ignite the filter separately and add to its ash the precipitate. Then ignite to bright redness, cool II] SOILS 23 in a desiccator and weigh as ferric oxid (Fe203), aluminium oxid (AUOs), and phos- phorus pentoxid (P2O5). Transfer this residue to a flask, digest with several cc. of sulphuric acid (1 to 4), and heat to accelerate solution. When solution is complete reduce with zinc and determine the ferrous iron by titration with a standard per- manganate solution, and calculate to ferric oxid; or, (2) In lieu of the above, evapo- rate 50 or lOOcc.of A, underll, with the addition of 10 cc. of su phuric acid until all hydrochloric acid is expelled, dilute with water, reduce with zinc and determine the ferrous iron by titration with a standard permanganate solution and calculate to ferric oxid. The weight of ferric oxid, plus that of the phosphorus pentoxid, determined under 17 or 19, subtracted from the collective weight of ferric oxid, aluminium oxid, and phosphorus pentoxid, gives the weight of the aluminium oxid. 1 4 MANGANESE.— OFFICIAL. Concentrate B, under 13, to about 50 cc, cool, add bromin water until the solution is colored, make alkaline with ammonium hydroxid, and heat to boiling in a covered beaker; cool, and repeat the addition of bromin water, of ammonium hydroxid and boil again. If a precipitate is obtained, slightly acidify the solution with acetic acid, filter immediately, and wash with hot water. Dry the precipitate, ignite and weigh as manganomanganic oxid (MnsO^). Designate the filtrate, or if there is no precipitate, the original solution, as C. 1 5 CALCIUM.— OFFICIAL. Concentrate C, under 14, to about 50 cc, make slightly alkaline with ammonium hydroxid, and add, while still hot, ammonium oxalate solution, drop by drop, slightly in excess of complete precipitation, to convert the magnesium also into oxalate. Heat to boiling, allow the precipitate to settle completely, decant the clear solution on a filter, pour 1.5-20 cc. of hot w^ater on the precipitate, and again decant the clear solution on the filter. Dissolve the precipitate in the beaker with a few drops of hj'drochloric acid, add a little water, repeat the precipitation as above, and filter through the same filter; transfer the precipitate to the filter and wash free from chlo- rin with hot water; dry, ignite the precipitate over the blast lamp to constant weight, and weigh as calcium oxid. Designate the filtrate and washings as D. 1 6 MAGNESIUM.— OFFICIAL. Evaporate D, under 15, to dryness on the water bath and heat carefully to expel ammonium salts. Treat the residue with 20-25 cc. of hot water and about 5 cc. of hydrochloric acid, filter and wash. Concentrate to about 50 cc, cool, and add suffi- cient disodium hydrogen phosphate solution to precipitate the magnesium; then add gradually ammonium hydroxid, with constant stirring, until the solution is distinctly alkaline. Determine if the precipitation is complete by the addition of more of the disodium hydrogen phosphate solution. After 30 minutes, add gradually 10 cc. of strong ammonium hydroxid, cover to prevent the escape of ammonia, and let stand in the cold. Filter after 12 hours, wash the precipitate free from chlorin, using dilute ammonium hvdroxid [I, 4 (d)], dry the filter and precipitate and trans- fer the latter to a weighed porcelain crucible. Ignite the filter separately and add its ash to the precipitate in the crucible. Burn at first at a moderate heat, then ignite to whiteness or to a grayish white, weigh as magnesium pyrophosphate (MgoPeO?) and calculate to magnesium oxid (MgO). 24 METHODS OF ANALYSIS [Chap. PHOSPHORIC ACID. 17 Gravimetric Method. — Official. Concentrate 100-200 cc. of A, under 11 , to about 25-30 cc, neutralize with ammo- nium hydroxid and add about 10 cc. additional. Dissolve the precipitate by the slow addition of dilute nitric acid, stirring constantly and avoiding a large excess, add gradually about 20 cc. of molybdate solution [I, 4 (a) ], and allow to stand for 1 or 2 hours in a water bath at a temperature of 40°C. After an hour determine if the precipitation is complete, as follows: Pipette about 5 cc. of the clear liquid into 5 cc. of warm molybdate solution. If any precipitate is produced, return the test liquid to the main portion, add more molybdate solution, and repeat the operation until all the phosphoric acid is precipitated. Then allow to stand for several hours at room temperature, preferably overnight. Filter off the ammonium phosphomolyb- date, wash the precipitate thoroughly with cold water, dissolve with ammonium hydroxid, and determine as magnesium pyrophosphate, as directed under I, 6 and calculate to phosphorus pentoxid (P2O5). Volumetric Method. — Tentative. 1 8 REAGENTS. (a) Standard sodium or potassium hydroxid solution. — Strength such that 1 cc. of this solution is equivalent to 0.0005 gram of phosphorus pentoxid (P2O6). (b) Standard nitric acid solution. — Strength same as the standard alkali solution described under (a) as determined by titration, using phenolphthalein as indicator. 19 DETERMINATION. Proceed as in 1 7 until all the phosphoric acid is precipitated and then complete the determination in the following manner: Allow the solution containing the yellow precipitate to stand for at least 3 hours at a temperature not above 40°C., filter on a small filter paper or on a Gooch crucible and wash with cold water until the filtrate from 2 fillings of the filter yields a slight pink color on the addition of phenolphthalein and 1 drop of the standard alkali. Return the filter and precipitate to the same beaker used for precipitating the phosphomolybdate, dissolve the yellow precipitate in the standard sodium or potas- sium hydroxid solution, add a few drops of phenolphthalein and titrate the excess of alkali with the standard acid. Calculate to phosphorus pentoxid (PaOs). 20 SULPHURIC ACID.-OFFICIAL. Evaporate 100-200 cc. of A, under 11 , nearly to dryness on a water bath to expel the excess of acid, add 50 cc. of water, heat to boiling and add, drop by drop, 10% barium chlorid solution until no further precipitation occurs. Continue the boiling for about 5 minutes and allow to stand for 5 hours or longer in a warm place. Decant the liquid on an ashless filter or tared Gooch, previously heated, treat the precipitate with 15-20 cc. of boiling water, transfer to the filter and wash free from chlorin with boiling water. Dry the precipitate and filter, ignite, weigh as barium sulphate and calculate to sulphur trioxid (SO3). POTASSIUM AND SODIUM. 21 Method I.— Official. (1) Treat the filtrate from 20 with ammonium hydroxid exactly as in 13. Evaporate the filtrate and washings to dryness, heat below redness until ammo- nium salts are expelled, dissolve in hot water, add 5 cc.of barium hydroxid solution, II] SOILS 25 and heat to boiling; let settle for a few minutes, and determine if the precipitation is complete by the addition of barium hydroxid solution to a little of the clear liquid. When no further precipitate is produced, filter and wash thoroughly with hot water. Heat the filtrate to boiling, add ammonium hydroxid and ammonium carbonate to complete the precipitation of the barium, calcium, etc., let stand a short time on the water bath, filter, and wash the precipitate thoroughly with hot water; evaporate the filtrate and washings to dryness, expel ammonium salts by heating below red- ness, treat with a little hot water, add a few drops of ammonium hydroxid, 1 or 2 drops of ammonium carbonate, and a few drops of ammonium oxalate; let stand a few minutes on the water bath, set aside for a few hours, filter, evaporate to complete dryness on the water bath, and heat to dull redness until all ammonium salts are expelled and the residue is nearly or quite white. Dissolve in a minimum amount of water, filter into a tared platinum dish, add a few drops of hydrochloric acid, evap- orate to dryness on the water bath, heat to dull redness, cool in a desiccator, and weigh as potassium and sodium chlorids. Repeat the heating until constant weight is obtained. Dissolve in a small amount of water; if any residue remains, the sepa- ration must be repeated until the residue of potassium and sodium chlorids is entirely soluble. Dissolve the residue with water, add an excess of platinic chlorid solution [1,40 (b)], proceed as directed under I, 45 and calculate to potassium oxid (KjO); or, (2) Instead of the foregoing, evaporate to dryness a fresh aliquot of A, under 11, redissolve in water, treat directly with barium hydroxid solution, and from this point proceed as directed above in (1). 22 Method II.— Tentative. Proceed as in 21 through "let stand a short time on the water bath" (the point at which the barium, calcium, etc., have been precipitated with ammonium hydroxid and ammonium carbonate) and then proceed as follows: Filter into a beaker, add 1 or 2 drops of hydrochloric acid and 1 cc. of ammonium sulphate (75 grams to 1 liter), digest several hours on a water bath, and filter into a tared platinum dish. Evaporate to dryness, heat to full redness, add 1 gram of powdered ammonium carbonate; heat to expel excess of ammonium carbonate, cool, and weigh the sulphates of sodium and potassium. Determine potassium as directed under I, 42 (a) and calculate to potassium oxid (K2O). TOTAL PHOSPHORUS. 23 Magnesium Nitrate Method. — Official. Place 5 grams of soil, as prepared under 2, in a porcelain dish. Moisten with 5-7 cc. of magnesium nitrate solution [I, 4 (e) ]. Dry on the water bath and burn off the organic matter at low redness. Cool, moisten slightly with water, add 10 cc.of concentrated hydrochloric acid, and digest 2 hours on the water bath, keeping the dish covered with a watch glass and stirring 2 or 3 times during the digestion. Trans- fer to a 250 cc. graduated flask, cool, fill to the mark, mix well, and pass through a dry folded filter, pouring back on the filter until the filtrate becomes clear. Pipette an aliquot corresponding to 2 or 4 grams of the soil, depending upon the amount of phosphorus present, into a porcelain dish, evaporate to dryness, treat with hydro- chloric acid and water, filter, and wash; the combined volume should not exceed 40 cc. Make alkaline with ammonium hydroxid, and dissolve the precipitate by the slow addition of concentrated nitric acid, using a slight excess. Add gradu- ally, while shaking, 5-15 cc. of molybdate solution [I, 7 (a) ]. Keep the solution at 40°-50°C. for an hour^ let stand overnight at room temperature, filter, and wash well with cold water. Return the filter and precipitate to the same flask and deter- mine phosphorus volumetrically, as directed under 19. 26 METHODS OF ANALYSIS [Chap. 24 Sodium Peroxid Method. — Official. Place 10 grams of sodium peroxid in an iron or porcelain crucible and thoroughly mix with 5 grams of the soil as prepared under 2. If the soil has very little organic matter, add a little starch to hasten the action. Heat the mixture carefully by applying the flame of a Bunsen burner directly upon the surface of the charge and the sides of the crucible until the action starts. Cover the crucible until the re- action is over and keep at a low red heat for 15 minutes. Do not allow fusion to take place. By means of a large funnel and a stream of hot water, wash the charge into a beaker, acidify with hydrochloric acid and boil. Transfer to a 500 cc. gradu- ated flask, cool and fill to the mark. If the action has taken place properly there should be no undecomposed soil in the bottom of the flask. Allow the silica to settle and draw off 200 cc. of the clear solution. Precipitate the iron, aluminium, and phosphorus with ammonium hydroxid; filter, wash several times with hot water, wash the precipitate back into the beaker with a stream of hot water, and dissolve the precipitate in hot hydrochloric acid, pouring the acid upon the filter to dissolve any precipitate adhering to it. Evapo- rate the solution and washings to dryness on a water bath. Treat with dilute hy- drochloric acid, heating if necessary, and remove the silica by filtration. Con- centrate the filtrate and washings to about 10 cc, add 2 cc. of strong nitric acid, and make alkaline with ammonium hydroxid. Add nitric acid very slowly and with constant stirring until the solution is clear, avoiding an excess. Heat at 40°-50°C. on a water bath, add 15 cc. of molybdate solution, [I, 7 (a) ], and maintain this tem- perature for 1-2 hours. Let stand overnight, filter, and wash free from acid with 0.1% solution of ammonium nitrate, and, finally, once or twice with cold water. Transfer the filter and precipitate to the same beaker and determine phosphorus volumetrically as directed under 19. 25 TOTAL POTASSroM.-OFFICIAL. Decompose the soil by the J. L. Smith method^ as follows: Triturate gently 0.5 or 1 gram of the finely ground soil with 1 gram of dry ammonium chlorid in a smooth mortar, then add 8 parts of calcium carbonate and mix intimately. Trans- fer the mixture to a platinum crucible, rinsing the mortar with a little calcium car- bonate. Heat the crucible gradually until fumes of ammonium salts no longer appear, and continue until the lower Ihree-fourths only of the crucible are brought to a red heat. Maintain this temperature 40-60 minutes. The temperature should be sufficient to keep the calcium chlorid formed by the reaction of ammonium chlo- rid with calcium carbonate in a state of fusion. The mass, however, does not be- come liquid since the fused calcium chlorid is absorbed by the large quantity of calcium carbonate present. If the silicate "s fused by the application of too strong heat, disintegration of the mass at the end of the operation with water cannot be effected. Moreover, too high a temperature causes volatilization of alkali chlorids. The mass contracts in volume during the ignition, and is usually easily detached from the crucible. Transfer the fused mass to a porcelain dish, thoroughly slake with hot water, and grind thoroughly with an agate pestle. After washing 5 times by decantation with hot water, transfer to a filter and wash well, 300 cc. of wash water being sufficient. To the filtrate add 10 cc. of concentrated hydrochloric acid, and evaporate nearly to dryness in a porcelain dish. Treat with hot water and 2 cc. of hydrochloric acid and filter by means of suction through a small filter into a 150 cc. Jena beaker. Concentrate the solution to 30 cc, add 1.5 cc. of platinic chlorid solution [I. 40 (b) ], evaporate to a sirupy consistency, and add 15 cc. of 2.25 N/1 acidulated alcohol (prepared by passing hydrochloric acid gas into a mix- II] SOILS 27 ture of 2000 cc. of 95% alcohol and 152 cc. of hydrochloric acid, sp. gr. 1.20). Fil- ter by means of suction through a small filter, wash with 80% alcohol, then with ammonium chlorid solution [I, 40 (a) ], and finally with 80% alcohol. Dry the precipitate on the filter and wash the precipitate with hot water into a weighed platinum dish, using suction. Evaporate to dryness, heat in a drying oven for an hour at 120°C., cool in a desiccator, weigh and calculate to potassium oxid (KjO). TOTAL ALKALIES. 26 /. Lawrence Smith Method.* — Official. (1) Proceed as directed under 25 to the point indicated by the phrase "300 cc. of wash water being sufficient" (the point at which the ignited mass has been disintegrated and thoroughly washed with water). The filtrate contains the sili- cate alkalies in the form of chlorids together with calcium chlorid and hydroxid. Precipitate the calcium at once with ammonium carbonate solution; allow to settle, decant the supernatant liquid into a porcelain (or platinum) dish, concentrate and finally transfer the precipitate to the dish. When the volume is reduced to about 30 cc, add a little ammonium carbonate solution and ammonium hydroxid, heat and filter into a porcelain (or platinum) dish, evaporate the filtrate to dryness on a water bath and expel ammonium salts by ignition. Dissolve the residual alkali chlorids in 3-5 cc. of water; a little black or dark brown flocculent matter usually remains undissolved, while the solution may also contain traces of calcium. Add 2-3 drops of ammonium carbonate and ammonium hydroxid, warm gently, and fil- ter through a very small filter into a weighed platinum vessel. Evaporate to dry- ness on a water bath, heat the alkali chlorids to incipient fusion, cool, and weigh as sodium and potassium chlorids; or, (2) Determine, by the above method, the quantity of alkalies in the insoluble residue, 12, and add that obtained under 21 or 22. 27 PHOSPHORUS SOLUBLE IN N/5 NITRIC ACID.— TENTATIVE. Digest 10 grams of air-dried soil in a stoppered flask, with 100 cc. of N/5 nitric acid, for exactly 5 hours in a water bath kept at a temperature of 40°C. Filter the solution through a dry paper, cool to room temperature, and titrate 20 cc. of the filtrate with standard potassium hydroxid solution (carbonate-free), using phenol- phthalein as indicator. From the data thus secured calculate the number of cc. of N/1 acid and of water to make exactly 1 or 2 liters of acid of N/5 strength after allowing for the quantity neutralized by the amount of soil to be used in the fol- lowing procedure: Place 200 grams of the air-dried soil in a large, dry, glass-stoppered bottle and add exactly 2000 cc. of N/5 nitric acid corrected for neutralization as above de- scribed. With soils rich in available phosphoric acid, 100 grams of soil and 1000 cc. of acid will be sufficient. Digest in a large water bath at a temperature of 40°C. for exactly 5 hours, shaking thoroughly each half hour. At the end of the digestion shake the contents of the bottle well and pour quickly upon a large, dry, ribbed fil- ter of 2 thicknesses of paper and of sufficient size to receive the entire contents of the bottle. Collect the filtrate in a dry vessel, pouring back on the filter until the filtrate becomes clear. Evaporate 1000 or 500 cc. of the filtrate, according to the quantity of soil used, to dryness in a porcelain dish; add a few cc. of nitric acid to oxidize organic matter, etc., moisten the residue with hydrochloric acid, digest with water, and filter into a 500 cc. flask. Add a solution containing 15 grams of ammonium nitrate; then strong ammonium hydroxid until a permanent precipitate forms, and then concentrated nitric acid slowly until the precipitate dissolves. 28 METHOD OF ANALYSIS Dilute to about 100 cc, if less than that volume, place a thermometer in the flask, and heat to S5°C. Add 75 cc. of recently prepared molybdate solution [I, 4 (a) ], digest in a water bath at 80°C. for 15 minutes, with occasional shaking, remove from the bath and allow to stand at least 10 minutes before filtering. Continue the de- termination as directed under I, 6 and calculate to phosphorus pentoxid (PsOt). 28 CALCIUM CARBONATE REQUIRED.— TENTATIVE. Place 100 grams of soil, as prepared under 2, in a 400 cc. wide-mouthed bottle, add 250 cc. of N/1 potassium nitrate, stopper, and shake continuously for 3 hours in a shaking machine, or every 5 minutes by hand. Let stand overnight. Draw off 125 cc. of the clear, supernatant liquid, boil 10 minutes to expel carbon dioxid, cool, and titrate with standard sodium hydroxid solution, 1 cc. of which is equiva- lent to 4 mg. of calcium carbonate (0.001% on basis of the weight of soil used), using phenolphthalein as indicator. 29 STATEMENT OF RESULTS.-OFFICIAL. Calculate all results of soil analysis as per cent of the soil dried to constant weight as under 3 and state in the following order: Insoluble residue Soluble silica — Manganomanganic oxid (Mn304) Potassium oxid (K2O) Sodium oxid (NajO) Calcium oxid (CaO) Magnesium oxid (MgO) Ferric oxid (Fe203) Aluminium oxid (AI2O3) , Phosphorus pentoxid (P2O6) Sulphur trioxid (SO3) Organic carbon Inorganic carbon Volatile matter Total nitrogen Total phosphorus Total potassium Phosphorus soluble in N/5 acid Calcium carbonate required Total BIBLIOGRAPHY 1 J. Am. Chem. Soc, 1904, 26: 294, 1640. 2 J. Agr. Rci.,3: (II), 155. » J. Ind. Eng. Chem., 1914, 6: 465. * Fresenius. Quantitative Chemical Analvsis. Revised and amplified transla- tion of the 0th German ed., 1906, 2: 1175; Crookes. Select Methods in Chemical Analysis. 4th ed., 1005, p. 23; Wiley. Principles and Practice of Agricultural Analysis. 1906, 1: 423; U.S. Geol. Surv. l?ull. 422, p. 171; Am. J. Sci., 2nd ser., 1871, 50: 269; Am. Chem., 1871, 1; Ann. Chem. Pharm., 1871, 159: 82. III. PLANT CONSTITUENTS. 1 PREPARATION OF SAMPLE.— OFFICIAL. Thoroughly cleanse the material from all foreign matter, especially from adhering soil, air-dry, grind, and preserve the sample in tightly stoppered bottles. 2 PREPARATION OF ASH.— OFFICIAL. Ignite 10-20 grams of the substance, in a fiat-bottomed platinum dish in a muffle, at a comparatively low temperature. Do not employ a full red heat because of the danger of volatilizing alkali chlorids, etc. If rich in silica and alkalies, char the material, treat with water to dissolve soluble salts, filter through an ashless filter, dry the filter and paper and incinerate, add the filtrate to the incinerated residue, evaporate to dryness and ignite at a low red heat. If rich in phosphates, e.g., seeds and animal substances, char the material, dissolve soluble salts in dilute acetic acid, filter through an ashless filter, wash with water, dry and incinerate the filter and residue, add the filtrates to the incinerated residue, evaporate to dryness, and ignite gently. While still warm, pulverize the whole of the ash as obtained above, mix intimately and preserve in a tightly stoppered, dry bottle. If after incineration the ash has absorbed moisture, dry thoroughly at low redness before bottling. 3 CARBON DIOXID.-OFFICIAL. Determine carbon dio.xid in a weighed portion of the ash prepared under 2. Lib- erate the carbon dio.xid by treatment with dilute hydrochloric acid in any of the usual forms of apparatus, and determine the increase in weight of the potash bubs. The efficiency of the apparatus should be tested by blank determinations conducted upon weighed portions of pure calcite. 4 CARBON, SAND AND SILICA.— OFFICIAL. Transfer the residue from the carbon dioxid determination to a beaker or evapo- rating dish; evaporate to dryness; pulverize and dry thoroughly to render the silica insoluble. Moisten the dry residue with 5-10 cc. of hj'drochloric acid, add about 50 cc. of water, allow to stand on the water bath for a few minutes, filter through a hardened filter and wash thoroughly. Dilute the solution and washings to 250 cc. or other convenient volume. Designate as .4. Wash the residue from the filter into a platinum dish and boil for about 5 minutes with approximately 20 cc. of a saturated solution of pure sodium carbonate, add a few drops of pure sodium hydroxid solution, allow the solution to settle and decant through a tared Gooch filter. Boil the residue in the dish with sodium carbonate solution and decant as before. Repeat the process again, then transfer the residue to the Gooch filter, wash thoroughly, first with hot water, then with a little dilute hydrochloric acid, and finally with hot water until free from cblorin. Dry the filter and contents to constant weight at 110°C. to determine the combined weight of carbonaceous material and sand. Incinerate; the loss in weight represents the carbonaceous material; the residue is sand. Confirm by microscopic examination. Determine the soluble silica as follows: (1) Combine the alkaline filtrate and wash- ings, acidify with hydrochloric acid, evaporate to dryness and determine the silica 29 30 METHODS OF ANALYSIS [Chap. in the usual way; or, (2) Treat a weighed portion of the ash, as prepared under 2, with dilute hydrochloric acid. Evaporate to dryness; pulverize and dry thoroughly to render the silica insoluble. Moisten the dry residue with 5-10 cc. of hydrochloric acid, add about 50 cc. of water, allow to stand on the water bath for a few minutes, filter on an ashless filter, wash, dry, ignite and weigh to determine the combined weight of the silica and sand. Deduct the weight of the sand found above to obtain that of the silica. The soluble silica cannot be separated from the residue after ignition. 5 CARBON-FREE ASH.-OFFICIAL. Subtract the weights of the carbon found in 4 and the carbon dioxid found in 3 from that of the total ash used in 3. 6 FERRIC AND ALUMINIUM OXIDS.— OFFICIAL. (Applicable for plant materials other than seeds.) Pipette an aliquot of A, under 4, corresponding to 0.5 gram of ash, into a 250 cc. beaker. If ferrous iron is present, oxidize it by boiling with a few cc. of hydrogen peroxid or of concentrated nitric acid. Cool, add ammonium hydroxid until a precipitate begins to form, then nitric acid until just clear, and finally add 2-3 cc. of concentrated nitric acid in excess. Add 25 cc. of 50% ammonium nitrate solution, phosphate free, heat to 40°C., and add slowly, with constant shaking, a moderate excess of molybdate solution [1, 4 (a)], and allow to stand for 1 or 2 hours at a tem- perature not exceeding 40°C. After standing for an hour pipette 5 cc. of the clear solution into an equal volume of warm molybdate solution. If a precipitate forms in the test portion return it to the original solution and add more molybdate solu- tion. Allow to stand at room temperature for several hours, preferably overnight. Filter, wash with about 75 cc. of ammonium nitrate solution (2.5%, phosphate free, and slightly acidified with nitric acid) and combine the filtrate and washings. Des- ignate as B. Reserve the precipitate for the determination of phosphoric acid as described under 11. i Without concentrating solution 5, cai't-'ouply^eatralize with ammci,\ roxid, add a very slight excess of the alkali, avoiding a temperature higher than 40''C., and allow to stand at this temperature until the precipitate completely settles. Filter the clear supernatant liquid, wash the precipitate a few times by decantation with hot water before transferring to the filter, then wash 4 or 5 times on the filter. Dis- solve the precipitate on the filter with hot nitric acid (1 to 5), wash and reprecipitate as before. The combined filtrates and washings from the first and second precipi- tations should not exceed 500 cc. and should not be concentrated by evaporation. Designate as C and reserve for the determination of calcium and magnesium as described under 8. The same filter may be used for the second filtration, and the volume of the solution for the reprecipitation need not exceed 100 cc. Before the second filtration is made, a small quantity of ashless filter paper pulp should be added in order to facilitate the washing and leave the precipitate finely divided after the ignition, so that it can be easily fused with potassium hydrogen sulphate for the iron determination. Dry and ignite the precipitate and weigh as ferric and aluminium oxids. The iron oxid is determined in the following manner : Fuse, in a platinum crucible, the ignited precipitate with about 4 grams of fused potassium hydrogen sulphate. This fusion takes but a few minutes and must not be continued beyond the time actua ly needed. When completed the crucible is set aside and allowed to cool. Add 5 cc. of concentrated sulphuric acid and heat until copious fumes of sulphuric in] PLANT CONSTITUENTS 31 acid are given off. Cool, transfer to a flask, add water, and digest till the solution is clear. Reduce with zinc, cool, titrate with N/50 potassium permanganate and cal- culate to ferric oxid. If it is desired to use a larger amount of the sample for the iron determination, evaporate a suitable aliquot of A, under 4, with sulphuric acid, reduce with zinc, and titrate as above. MANGANESE, CALCIUM AND MAGNESIUM. (Applicable for plant materials other than seeds.) 7 Method I. —Official. To an aliquot of A, under 4, corresponding to 0.5-2 grams of ash, add a quantity of pure ferric chlorid solution, more than sufficient to combine with the phosphoric acid which may be present, and neutralize with ammonium hydroxid. Dissolve the precipitate in a very slight excess of hydrochloric acid and add 1-2 grams of sodium acetate. Boil for 1-2 minutes, filter at once, and wash with boiling water. Dissolve the precipitate in hydrochloric acid and reprecipitate as above. Concentrate the combined filtrates and washings to about 50 cc. and determine manganese, calcium and magnesium as directed under II, 14, 15, and 16. 8 Method 11.— Tentative. Calcium. — Make alkaline with ammonium hydroxid the combined filtrates and washings, C, under 6, and proceed as directed under 11,15. If the ignited calcium oxid has a brown coloration, due to manganese, dissolve in dilute hydrochloric acid and determine the manganese as directed below. Deduct the weight of mangano- manganic oxid thus obtained from the weight of the impure calcium oxid. Manganese. — Acidify the combined filtrates and washings from the calcium de- termination and evaporate to dryness in a porcelain casserole. Expel the ammonium salts by carefully heating the casserole from above, treat with a few cc. of hydro- chloric acid and water, filter off molybdic acid, and wash the precipitate until it is free frc orin. Bring the filtrate to a volume of 100 cc, add 1-2 drops of bromin, make a with a'^^monium h/drSx'"^'"; ..1' let stand for several minutes without agitation. Filter off the precipitated manganese, wash, dry, ignite, and weigh the precipitate as manganomanganic oxid. To this add the weight of the mangano- manganic oxid found as an impurity in the calcium determination. Magnesium. — Concentrate the alkaline filtrate from the manganese determination to 75 cc. and determine magnesium as directed under II, 16. PHOSPHORIC ACID. 9 Method I.— Official. Determine phosphoric acid in an aliquot of A, under 4, corresponding to 0.2-1 gram of ash, as directed under I, 6 or 9. 10 Method II. —Official. Determine phosphoric acid in the plant substance as directed under 1, 6, using suf- ficient material to give 0.2-1 gram of ash in the aliquot of the solution employed. 11 Method III. -Official. The phosphomolybdate precipitate obtained in 6 is used for the determination of phosphoric acid as directed under I, 6, beginning with "Dissolve the precipitate 32 METHODS OF ANALYSIS [Chap. on the filter with ammonium hydroxid, etc." or as under I, 9 (a), beginning with "Wash with cold water until the filtrate from 2 fillings of the filter yields a pink color, etc." 12 SULPHURIC ACID, SODIUM, AND POTASSIUM.— OFFICIAL. Boil an aliquot of A, under 4, corresponding to 0.5-1 gram of ash, add barium chlorid solution in small quantities until no further precipitate is formed, and pro- ceed as directed under II, 20 and 21 . ■|3 CHLORIN.— OFFICIAL. Determine as silver chlorid, either gravimetrically or by one of the standard volumetric procedures (as the Volhard method given below), in a nitric acid or aqueous solution of the ash. Volhard Methods 14 REAGENTS. (a) N/10 silver nitrate. (b) N/iO ammonium, or potassium sulphocyanate. (C) Ferric indicator. — Saturated solution of ferric alum. (d) Nitric acid. — Free from lower oxids of nitrogen, secured by diluting the usual pure acid with about 1/4 part of water, and boiling till perfectly colorless. 15 DETERMINATION. Dissolve a weighed portion of the ash, prepared under 2, in nitric acid (1 to 10). filter and wash with water. Add a known volume of the N/10 silver nitrate in slight excess to the combined filtrate and washings. Stir well, filter, and wash the silver chlorid precipitate thoroughly. To the filtrate and washings add 5 cc. of the ferric indicator and a few cc. of the nitric acid. Titrate the excess of silver with the N/10 sulphocyanate until a permanent light brown color appears. Calculate the amount of chlorin. 16 POTASSIUM IN PLANTS.-OFFICIAL. Determine potassium as directed under I, 42, using sufficient plant material to yield 0.5-1 gram of ash in the aliquot of the solution used for the potassium determi- nation. SULPHUR IN PLANTS. 17 Peroxid Method. — Official. Place 1.5-2.5 grams of material in a nickel crucible of about 100 cc. capacity and add 5 grams of pure anhydrous sodium carbonate. Mix thoroughly, using a nickel or platinum rod, and moisten with approximately 2 cc. of water. Add pure sodium peroxid, approximately 0.5 gram at a time, thoroughly mixing the charge after each addition. Continue adding the peroxid until the mixture becomes nearly dry and quite granular, requiring usually about 5 grams of peroxid. Place the crucible over a low alcohol or other sulphur-free flame and heat carefully with occasional stirring until the contents are fused. (Should the material ignite, the determination is worthless.) After fusion remove the crucible, allow to cool somewhat, and cover the hardened mass with peroxid to a depth of about 0.5 cm. Heat gradually, and finally with full flame until fusion again takes place, rotating the crucible from time to time in order to bring any particles adhpring to the sides into contact with the oxidizing material. Continue the heating for 10 minutes after fusion is complete. ni] PLANT CONSTITUENTS 33 Cool somewhat, place the warm crucible and contents in a 600 cc. beaker and care- fully add about 100 cc. of water. After the initial violent action has ceased, wash the material out of the crucible, make slightly acid with hydrochloric acid (adding small portions at a time), transfer to a 500 cc. flask, cool, and make to volume. Filter, and determine sulphates in 200 cc. of the filtrate as directed under II, 20. 18 CHLORIN IN PLANTS.— TENTATIVE. Moisten 5 grams of the substance in a platinum dish with 20 cc. of a 5% solution of sodium carbonate, evaporate to dryness, and ignite as thoroughly as possible at a temperature not exceeding dull redness. Extract with hot water, filter and wash. Return the residue to the platinum dish and ignite to an ash; dissolve in nitric acid, add this solution to the water extract and determine chlorin as directed under 15. BIBLIOGRAPHY. ' Sutton. Volumetric Analysis. 10th ed., 1911, p. 145. IV. WATERS. POTABLE WATER. TURBIDITY.— TENTATIVE. 1 REAGENTS. (a) Standard turbidity solution. — Weigh out 1 gram of elutriated fuller's earth previously dried and sifted through a 200 mesh sieve. Make up to a liter. If the fuller's earth is of good quality and the proper degree of fineness, this stock solution has a turbidity of 1000. Check the stock solution with a Jackson turbidimeter. (b) Turbidity standards. — Prepared by dilution of (a). 2 DETERMINATION. Determine the turbidity of the sample with a Jackson turbidimeter equipped with either candle or electric light. If the turbidity is less than 100, which pro- hibits the use of the turbidimeter, determine by direct comparison with turbidity standards contained in bottles of clear white glass. COLOR.— TENTATIVE. 3 REAGENTS. (a) Standard color solu'ion. — Dissolve 1.246 grams of potassium platinic chlorid (PtCl42KCl) and 1 gram of crystallized cobalt chlorid (C0CI26H2O) in a small quan- tity of water, add 100 cc. of concentrated hydrochloric acid and make up to 1 liter with water. This stock solution has a color of 500. (b) Color standards. — Prepared by dilution of (a). 4 DETERMINATION. Compare the color of the sample, freed from suspended matter, with color standards in tubes of clear white glass. 5 ODOR.— TENTATIVE. Shake the vessel containing the sample and note the odor. Heat a portion of the sample just to boiling and note the odor. 6 TOTAL SOLIDS.-OFFICLAL. Thoroughly shake the vessel containing the sample and pipette 100 cc. of the un- filtered water into a weighed platinum dish. If the sample contains much suspended matter, shake, pour rapidly into a 100 cc. measuring cylinder, and transfer without delay to a weighed platinum dish; evaporate to dryness and heat to constant weight at 105°C. In the case of highly mineralized waters it is advisable to weigh again after drying at 1S0°C. 7 SOLIDS IN SOLUTION.— OFFICIAL. Allow the sample to stand until all sediment has settled, and filter if necessary to secure a perfectly clear liquid. Occasiona ly a clear filtrate can only be obtained by the use of alumina cream but this should be avoided if possible. Evaporate 100- 35 36 METHODS OF ANALYSIS [Chap. 250 cc. to dryness in a weighed platinum dish. Heat to constant weight at 105**C. In the case of highly mineralized waters it is advisable to weigh again after drying at 180°C. g SUSPENDED MATTER.— OFFICIAL. (1) The difference between the values for total solids and dissolved solids rep- resents the suspended matter; or, (2) Determine the suspended matter directly by filtering a suitable quantity of the water through a tared Gooch crucible, suitably prepared, and weighing after drying at 105°C. 9 IGNITED RESIDUE.— OFFICIAL. Ignite the residue from 6 at a low red heat until the ash is white or nearly so. Note any odor or change in color produced during ignition. Record the weight of the ignited residue and calculate the loss on ignition. FREE AND ALBUMINOID AMMONIA.— OFFICIAL. 10 REAGENTS. (a) Saturated solution of sodium carbonate. (b) Ammonia-free water. (C) Standard ammoriium chlorid solution. — One cc. is equivalent to 0.01 mg. of nitrogen in the form of ammonia (NH3). (d) Nessler reagent. — Dissolve 50 grams of potassium iodid in aminimum quantity of cold water. Add a saturated solution of mercuric chlorid until a slight perma- nent precipitate is formed. Add 400 cc. of 50% solution of potassium hydroxid (or an equivalent quantity of sodium hydroxid), dilute to 1 liter, allow to settle, and decant. (e) Alkaline potassium permanganate solution. — Dissolve 200 grams of potassium hydroxid and 8 grams of potassium permanganate in water and dilute to 1 liter. 11 DETERMINATION. Connect a flask of about 1500 cc. capacity with an upright bulb condenser by means of a rather large glass tube and a soft rubber stopper or a recently extracted cork stopper. Place in the flask 5 cc. of the saturated solution of sodium carbonate and 500 cc. of ammonia-free water. Distil into 50 cc. Nessler tubes until no further traces of ammonia are indicated on the addition of 2 cc. of the Nessler reagent to 50 cc. of the distillate. Continue the distillation until the volume of the solution in the flask has been reduced to about 200 cc. Cool slightly, add 500 cc. of the water under examination, and distil, at the rate of 1 tubeful in 15 minutes, into 50 cc. Nessler tubes until ammonia ceases to be given off' (4 or 5 tubes are usually sufficient). Add 2 cc. of the Nessler reagent to each tube and let stand 10 minutes. Freshly prepare in a similar manner other tubes containing known amounts of the standard ammonium chlorid, made up to 50 cc. with ammonia-free water, and compare the nesslerized distillates with these. Report as milligrams per liter of nitrogen in the form of free ammonia (NHj). Cool the flask and add 50 cc. of the alkaline perman- ganate recently boiled. Distil, at the rate of 1 tubeful in 15 minutes, into 50 cc. Nessler tubes until ammonia ceases to come off. Nesslerize and compare as in the determination of free ammonia. Report as milligrams per liter of nitrogen in the form of albuminoid ammonia (NHj). rV] WATERS 37 NITROGEN IN THE FORM OF NITRITE.— OFFICIAL. 12 REAGENTS. (a) Concentrated hydrochloric acid. — Sp. gr. 1.2. (b) Sulphanilic acid solution. — Dissolve 1 gram of sulphanilic acid in 100 cc. of hot water. (C) Alpha-naphthylamin hydrochlorid solution. — Boil 0.5 gram of the salt with 100 cc. of water for 10 minutes at constant volume. (d) Standard nitrite solution. — Dissolve 1.1 gram of silver nitrite in nitrite-free water, precipitate the silver with sodium chlorid solution and dilute to 1 liter, mix and allow to settle. Dilute 100 cc. to 1 liter and then 10 cc. of this solution to 1 liter, using in each case nitrite-free water. Each cc. of the last solution is equivalent to 0.0001 mg. of nitrogen as nitrite. 1 3 DETERMINATION. Place 100 cc. of the water in a 100 cc. Nessler tube and treat with 1 or 2 drops of concentrated hydrochloric acid. Add 1 cc. of the sulphanilic acid, 1 cc. of the alpha- naphthylamin hydrochlorid, and thoroughly mix. Set aside for 30 minuteswith other Nessler tubes containing known amounts of the standard nitrite made up to 100 cc. with nitrite-free water, and treated with hydrochloric acid, sulphanilic acid, and alpha-naphthylamin hydrochlorid in the manner just described. Determine the amount of nitrite by comparing the depth of pink color in the known and unknown solutions. Record as nitrogen in the form of nitrite. NITROGEN IN THE FORM OF NITRATE. Phenoldisulphonic Acid Method. — Official. (For water of low chlorin content.) 14 REAGENTS. (a) Phenoldisulphonic acid solution. — Dissolve 25 grams of pure white phenol in 150 cc. of concentrated sulphuric acid, add 75 cc. of fuming sulphuric acid (13-15% SOs) and heat at 100°C. for 2 hours. (b) Standard nitrate solution. — Dissolve 0.722 gram of pure potassium nitrate in 1 liter of nitrate-free water. Evaporate 50 cc. of this solution to dryness in a porce- lain dish; treatwith2cc.of the phenoldisulphonic acid solution, rubbing with a glass rod to insure intimate contact. Dilute to 500 cc. ; 1 cc. is equivalent to 0.01 mg. of ni- trogen as nitrate. This solution is permanent. Standards for comparison are pre- pared by adding ammonium hydroxid to measured volumes of it in 100 cc. Nessler tubes. (C) Standard silver sulphate solution. — Dissolve 4.3969 grams of silver sulphate, free from nitrate, in 1 liter of water; 1 cc. is equivalent to 1 mg. of chlorin. (d) Ammonium hydroxid. — Sp. gr. 0.90. 15 DETERMINATION. Take 100 cc. of the sample, or an amount that will contain 0.05 mg. or less of nitrogen as nitrate, and add standard silver sulphate, precipitating all but about 0.5 mg. of the chlorin. Heat to boiling, allow to settle, or add a little alumina cream, filter, and wash with small amounts of hot water. Evaporate the filtrate to drynes* in a porcelain dish on the water bath; when cool, treat with 2 cc. of the pheuoldieul- phonic acid solution as in 14 (b). Dilute with water and add slowly ammonium hy- 38 METHODS OF ANALYSIS [Chap. droxitl until the maximum color is developed. Transfer to a colorimetric cylinder, filter if necessary, and compare with the standards in the usual manner. Record as nitrogen in the form of nitrate. Reduction Method. — Official. (For water of high chlorin content.) 16 REAGENTS. (a) Sodium or potassium hydroxid solution. — Dissolve 250 grams of the purest hydroxid obtainable in 1250 cc. of water and boil down to 1 liter. (b) Aluminium foil. — Use strips about 10 cm. long, weighing about 0.5 gram. 17 DETERMINATION. Place 10 cc. of the sample in a 100 cc. test tube and dilute to exactly 50 cc. ; add 5 cc. of the sodium hydroxid and a strip of the aluminium foil. Close the mouth of the test tube with a rubber stopper carrying a U-shaped glass tube connected with a second test tube containing about 50 cc. of ammonia-free water acidified with hydro- chloric acid, which serves as a trap to catch any ammonia which might escape. Allow to stand at room temperature for 12 hours or more until reduction is complete. Trans- fer the contents of the first tube to a Kjeldahl flask and distil. Cool the distillates and nesslerize as directed under 1 1 ; also nesslerize the solution in the trap. Record as nitrogen in the form of nitrate. CHLORIN.— OFFICIAL. 18 REAGENTS. (a) N/20 sulphuric acid. (b) N /20 sodium, carbonate. (C) Potassium chromate indicator. — Dissolve 5 grams of potassium chromate in water, add a solution of silver nitrate until a slight permanent red precipitate is produced, filter, and dilute to 100 cc. (d ) Standard silver nitrate solution. — Dissolve 4.791 grams of silver nitrate in water and dilute to 1 liter; 1 cc. is equivalent to 1 mg. of chlorin. Check by titration against a standardized solution of sodium chlorid. 19 DETERMINATION. To 100 CC. of the water add a few drops of phenolphthalein. If a red color appears, titrate the carbonates thus indicated to bicarbonates with N/10 or N/20 sulphuric acid. If the water is acid to methyl orange, add N/20 sodium carbonate to neutralize the acidity. Add 1 cc.of the potassium chromate and titrate with the standard silver nitrate. Correct for the amount of silver nitrate necessary to give in 100 cc. of chlorin- free water with 1 cc. of the chromate, the shade obtained at the end of the titration of the sample. lodids and bromids are not usually found in interfering quantities in potable water. However, if they are present make the equivalent correction. If chlorids are present in very small quantities concentrate 500 or 1000 cc. in a por- celain dish to 100 cc, rub down the sides of the dish carefully, add 1 cc. of the indicator and titrate as described above. If sufficient chlorids are present in 100 cc. of the water to consume more than 25 cc. of the standard silver nitrate, determine by precipita- tion in nitric acid solution and weigh the silver chlorid. IV] WATERS 39 OXYGEN REQXTIRED. Method I.— Official. 20 REAGENTS. (a) Standard potassium permanganate solution. — Dissolve 0.3952 gram of potas- sium permanganate in 1 liter of water; each cc. has 0.1 mg. of oxygen available for oxidation. (b) Standard oxalic acid solution. — Dissolve 0.7875 gram of crystallized oxalic acid in 1 liter of water. Determine the value of the oxalic acid in terms of the permanganate by boiling 10 cc. of the oxalic acid and 200 cc. of redistilled water (prepared by treating distilled water with alkaline permanganate and distilling) with 10 cc. of sulphuric acid (1 to 3) and titrating, while still boiling, with the standard permanganate to the appear- ance of a pink color. 21 DETERMINATION. Add 10 cc. of sulphuric acid (1 to 3) to 200 cc. of the water in a porcelain dish and heat to boiling. Add from a burette the standard permanganate until the water is distinctly red and boil for 10 minutes, adding more of the standard permanganate from time to time to maintain the red color. Add 10 cc. of the standard oxalic acid and titrate back with the standard permanganate to a pink color. From the total number of cc. used of the permanganate subtract the number of cc. equivalent to 10 cc. of the oxalic acid. The result gives the number of cc. of the permanganate required for 200 cc. of the water. Correct for sulphids, nitrites and ferrous salts, if present, by subtracting the number of cc. of the standard permanganate absorbed by another 200 cc. portion of the sample when treated as above, digesting at room temperature for 3 minutes. Method II. {Schulze-Trommsdorf Method.^) — Tentative. (To be used when the chlorin content of the sample is high.) 22 REAGENTS. (a) 50% sodium hydroxid solution. Other reagents and standard solutions are described under 20. 23 DETERMINATION. Introduce 100 cc. of the water to be examined in a 300 cc. flask, add 0.5 cc. of the sodium hydroxid and 10 cc. of the permanganate, boil for 10 minutes, allow to cool to 50°-60°C. and add 5 cc. of the dilute sulphuric acid and 10 cc. of the standard oxalic acid. As soon as the liquid has become perfectly colorless, and while constantly agita- ting, cautiously add from a burette, drop by drop, the standard permanganate, until the liquid acquires a faint permanent redness. The permanganate required to effect this is the quantity required for the decomposition of the organic matter in the 100 cc. of water. If 100 cc. of the water require more than 4 cc. of the permanganate for the oxidation of organic matter, a second determination must be made using more of the per- manganate and a correspondingly larger quantity of the sodium hydroxid, as unde- composed permanganate remaining after boiling must be at least twice as great as the quantity decomposed. 40 METHODS OF ANALYSIS [Chap. DISSOLVED OXYGEN. Method I. (Winkler Method as Modified by Drown and Hazen.^)~Tentativ.. (When less than 0.1 mg. of nitrite nitrogen per liter is present.) 24 REAGENTS. (a) Manganous sulphate solution. — Dissolve 48 grams of nianganous sulphate in 100 cc. of water. (b) Sodium hydroxid-potassium iodid solution. — Dissolve 360 grams of sodium hydroxid and 100 grams of potassium iodid in 1 liter of water. (C) Sulphuric acid. — (Sp. gr. 1.4). Mi.x equal weights of concentrated sulphuric acid and water. (d) Standard sodium thiosulphate solution. — Dissolve 6.2 grams of recrystallized sodium thiosulphate in 1 liter of water. This gives a N/40 solution, each cc. of which is equivalent to 0.2 mg. of oxygen or 0.1395 cc. of oxygen at O'^C. and 760 mm. pressure. This solution should be standardized occasionally against N/40 potassium dichromate. (e) Starch indicator. — Mix about 2 grams of clean starch with cold water to a thin paste; pour into about 200 cc. of boiling water. Boil for a few minutes. This solu- tion should be freshly prepared. 25 COLLECTION OF SAMPLE. Collect the sample in a carefully calibrated glass stoppered bottle, approximately 250 cc. capacity, by means of an apparatus designed to avoid the entrainment or absorption of any oxygen from the atmosphere. Note the temperature. 26 DETERMINATION. Add approximately 2 cc. of the manganous sulphate and 2 cc. of the sodium hydrox- id-potassium iodid, delivering both of these solutions beneath the surface of the liquid by means of a pipette. Insert the stopper and mix the contejits of the bottle by shaking. Allow the precipitate to settle. Remove the stopper; add about 2 cc. of sulphuric acid and mix thoroughly. Rinse the contents of the bottle into a flask; titrate with N/40 sodium thiosulphate, using a few cc. of the starch indicator toward the end of the titration. Do not add the starch until the color has become a faint yellow; titrate until the blue color disappears. Express the results in milligrams per liter and in percentage of saturation.^ This latter determination is the ratio of the amount of gas present to the maximum amount capable of being dissolved by distilled water at the same temperature and pressure. Method II. (Winkler Method as Modified by Rideal and Stewart.*) — Tentative. (When more than 0.1 mg. of nitrite nitrogen per liter is present.) 27 . REAGENTS. (a) N/10 potassium permanganate. (b) S% potassium oxalate solution. Other reagents are described under 24. 28 COLLECTION OF SAMPLE. Proceed as directed under 25. IV] WATERS 41 29 DETEHMINATION. Preli7ninary test. — Determine the amount of the permanganate required to oxi- dize the nitrite to nitrate by acidifying a preliminary sample of 50 cc. with 1 cc. of the sulphuric acid and adding the permanganate until a slight pink color remains after standing 10 minutes. Calculate the amount of the permanganate required for a sample collected as described under 25. To the sample add 1 cc. of the sulphuric acid and about 0.1 cc. of the perman- ganate in excess of the calculated amount required to oxidize the nitrite to nitrate. If more than 10 cc. of the permanganate are required add an additional 1 cc. of the sulphuric acid. Rotate the bottle and allow to stand for 10 minutes, after which destroy any excess of the permanganate by adding from a pipette 0.5-1 cc. of the oxalate. Insert the stopper and rotate as before. The color quickly disappears, and when decolorized add approximately 2 cc. of the manganous sulphate and 2 cc. of the sodium hydroxid-potassium iodid and proceed as in 26. Express the results in milligrams per liter and percentage saturation.' MINERAL WATER. 30 SPECIFIC GRAVITY.-TENTATIVE. Determine specific gravity at -^qt by means of a pycnometer. 31 SOLIDS IN SOLUTION.— OFFICIAL. Determine as directed under 7. 32 IGNITED RESIDUE.— OFFICIAL. Determine as directed under 9. 33 FREE AND ALBUMINOID AMMONIA.— OFFICIAL. Determine as directed under 1 1 . 34 NITROGEN IN THE FORM OF NITRITE. -OFFICIAL. Determine as directed under 13. 35 NITROGEN IN THE FORM OF NITRATE.— OFFICIAL. Determine as directed under 15 or 17. 36 CHLORIN.-OFFICIAL. Determine as directed under 19. 37 HYDROGEN SULPHID.— TENTATIVE. Place 0.5-2 cc. of N/100 iodin in a 500 cc. flask and add the water until the color of the iodin disappears. Add 5 cc. of the starch indicator and then N/100 iodin until a blue color appears. Fill the flask to the mark with water, noting the amount added. Subtract the quantity of water, iodin solution, and the starch indicator added, to determine the quantity of the water titrated. An excess of iodin is re- quired to produce a blue color. A correction is obtained by adding 5 cc. of the starch indicator to 500 cc. of water and then adding N/100 iodin until the color matches that of the sample under examination. Correct the original titration by the amount of iodin used in the blank. 42 METHODS OF ANALYSIS [Chap. 38 FREE CARBON DIOXID.— TENTATIVE. ' If the water reacts acid to phenolphthalein and alkaline to methyl orange, titrate 100 cc. with N/20 sodium carbonate (free from bicarbonate) until the solution ia neutral to phenolphthalein. The number of cc. used multiplied by 1.1 gives the milligrams of free carbon dioxid in 100 cc. Express results in milligrams per liter. 39 CARBONIC AND BICARBONIC ACIDS.— OFFICIAL. To 100 cc. of the water add a few drops of phenolphthalein and, if a pink color is produced, titrate with N/20 crystallized potassium hydrogen sulphate or sulphuric acid, adding a drop every 2 or 3 seconds, until the red color disappears. Multiply the burette reading by the factor 3 which gives the milligrams of the carbonic acid ion in 100 cc. To the colorless solution from this titration, or to the original solution if no color is produced with phenolphthalein, add 1 or 2 drops of methyl orange; con- tinue the titration without refilling the burette and note the total reading. If carbonic acid is absent, multiply the total burette reading by the factor 3.05, which gives the value of the bicarbonic acid ion in milligrams per 100 cc. If carbonic acid is present, multiply the reading with phenolphthalein by 2 and subtract from the total reading of the burette. Multiply the difference by 3.05, which gives the bicarbonic acid ion in milligrams per 100 cc. Express results in milligrams per liter. Silica, Iron, Aluminium, Calcium. Strontium and Magnesium. 40 silica.-official. Make a preliminary examination, using 100-250 cc. of water to determine the approximate quantity of calcium and magnesium present, in order to ascertain the quantity of water to be evaporated for the final analysis. Evaporate a quantity, usually 1-5 liters, of the water sufficient to yield 0.1-0.6 gram of calcium oxid or 0.1-1 gram of magnesium pyrophosphate. Acidify the water with hydrochloric acid and evaporate on the water bath to dryness in a plati- num dish; continue the drying for about an hour. Thoroughly moisten the residue with 5-15 cc. of hydrochloric acid (1 to 1). Allow to stand 10-15 minutes and add sufficient water to bring the soluble salts into solution. Heat on the steam bath until solution of the salts is effected. Filter to remove most of the silica and wash thoroughly with hot water. Evaporate the filtrate to dryness; treat with 5-10 cc. of the hydrochloric acid and sufficient water as above. Heat, filter, and wash thoroughly with hot water. Designate the filtrate as A . Transfer the 2 residues to a platinum crucible, ignite, heat over a blast lamp and weigh. Moisten the contents of the crucible with a few drops of water. Add a few drops of concentrated sulphuric acid and a few cc. of hydrofluoric acid and evaporate on the water bath under a good hood. Repeat the treatment if all the silica is not volatilized. Dry carefully on a hot plate, ignite, heat over a blast lamp, and weigh. The difference between the two weights 'S the weight of the silica. The residue in the crucible consists of alumin- ium and iron oxids. The weight of this residue is added to that of the total alumin- ium and iron oxids obtained in 41 . (If the above residue weighs more than 0.5 mg., barium sulphate may be found here when barium is present in the water. If so, make the necessary correction and add to the weight of the total iron and aluminium oxids in 41 .) 41 IRON AND aluminium.— OFFICIAL. Concentrate A , under 40, to about 200 cc. ; while still hot, add ammonium hydroxid slowly with constant stirring until alkaline to methyl orange. Boil, filter, and wash 2 or 3 times with hot water. Dissolve the precipitate in hot hydrochloric acid. IV] WATERS 43 Dilute to approximately 25 cc, boil, and again precipitate with ammonium hydroxid; filter, wash thoroughly with hot water, dry, ignite, and weigh as iron and aluminium oxids. (In the presence of phosphoric acid, the weight of this residue must be cor- rected for the phosphorus pentoxid equivalent to the phosphoric acid found in 51 , making due allowance for the difference in the volumes of the water used for these determinations.) Designate the filtrate as B. IRON. 42 Colorimelric Method. (If the amount of iron is less than 1 mg.) Fuse in a platinum crucible the ignited precipitate of iron and aluminium oxids with fused potassium hydrogen sulphate, dissolve in water, and precipitate the iron and aluminium with ammonium hydroxid. Dissolve the precipitate on the filter paper in hydrochloric and nitric acids, dilute the solution, add ammonium sulphocyanate solution (1 to 20) and compare the color developed with that of calibrated color disks, or standards containing known amounts of iron. 43 Volumetric Method. Fuse in a platinum crucible the residue of iron and aluminium oxids with fused potassium hydrogen sulphate. This fusion takes but a few minutes and must not be continued beyond the time actually needed. When completed, the crucible is set aside and allowed to cool. Add dilute sulphuric acid and heat the crucible until the fused mass is dissolved. Evaporate on the water bath as far as possible; then heat gradually until copious fumes of sulphuric acid are given off. Dissolve in water and allow to stand on the water bath. Cool, transfer to an Erlenmeyer flask, and make up to such a volume that the solution does not contain more than 2.5% of free sulphuric acid. Pass hydrogen sulphid through the solution to reduce the iron and precipitate any platinum contaminating the residue from the fusion. (Zinc may be used instead of hydrogen sulphid for reducing the iron.) Filter, wash and again pass hydrogen sulphid through the solution to be certain that all the iron is reduced. Expel the hydrogen sulphid by boiling, at the same time passing a current of carbon dioxid through the solution; test the escaping gas with lead acetate paper to ascertain the complete removal of hydrogen sulphid. When hydrogen sulphid has been removed discontinue boiling and let the flask cool somewhat with- out discontinuing the current of carbon dioxid. Titrate the reduced iron with a standard permanganate solution (1 cc. equivalent to 1 mg. of Fe) and calculate as 44 ' ALUMINIUM.— OFFICIAL. In the absence of phosphates, subtract from the weight of iron and aluminium oxids, under 41 , the iron, under 42 or 43, calculated to oxid, to obtain the weight of aluminium o\id. Calculate to aluminium. 45 CALCIUM.— OFFICIAL. Concentrate B, under 41 , to 150-200 cc. and to this solution, containing not more than 0.6 gram of calcium, calculated as calcium oxid, or 1 gram of magnesium, cal- culated as magnesium pyrophosphate, add 1-2 grams of oxalic acid and sufficient hydrochloric acid to clear the solution. Heat to boiling and neutralize with ammo- nium hydroxid, stirring constantly. Add ammonium hydroxid in slight excess and alloi«' to stand 3 hours in a warm place. Filter off the supernatant liquid and wash 44 METHODS OF ANALYSIS [Chap. the precipitate once or twice by decantation with 1% ammonium oxalate solution. Dissolve the precipitate in hydrochloric acid, dilute to 100-200 cc, add a little oxalic acid, and precipitate as above. After standing 3 hours, filter, wash with the ammonium oxalate solution as above, dry, ignite, heat over a blast lamp, and weigh as calcium and strontium oxids. Subtract from this weight, the weight of strontium oxid equivalent to the strontium under 46. The difference is the weight of calcium oxid. Calculate to calcium. Designate the filtrate and washings as C. As a check on the calcium oxid, evaporate to dryness the filtrate from the stron- tium nitrate under 46, beginning with "Filter, wash with ether-alcohol mixture, etc.," dissolve the calcium nitrate in water, precipitate as oxalate, filter, wash, ignite, and weigh as calcium oxid. 46 STRONTIUM.— TENTATIVE. Dissolve the oxids under 45 in dilute nitric acid and test with the spectroscope for strontium. If strontium is present, transfer the nitric acid solution to a small Erlenmeyer flask. Evaporate nearly to dryness over a low flame and heat in an air bath at 150°-160°C. for 1 or 2 hours after the water is evaporated. Break up the dried material with a stirring rod, add 10-15 cc. of a mixture of equal parts of absolute alcohol and ether to dissolve the calcium nitrate. Cork the flask and allow to stand with frequent shaking for 2 hours or longer. Decant the solution through a 5.5 cm. filter, preserving the filtrate. Wash the residue several times by decantation with small portions of ether-alcohol solution. Dry the residue and the filter paper and wash the filter paper repeatedly with small portions of hot water, collecting the filtrate in the flask containing the main portion of the strontium nitrate residue. Add 1 or 2 drops of dilute nitric acid, evaporate, dry, pulverize, and treat with 10-15 cc. of ether-alcohol mixture as above. Cork the flask and let stand about 12 hours with occasional shaking. Filter, wash with ether-alcohol mixture until a few drops of the filtrate evaporated on a watch glass leave practically no residue. Dry the paper and precipitate. Dissolve the strontium nitrate in a few cc. of hot water. Add a few drops of sulphuric acid, then a volume of alcohol equal to the volume of the solution and allow to stand 12 hours. Filter, ignite, weigh as strontium sulphate and calculate to strontium. Test spectroscopically for absence of calcium. 47 MAGNESIUM.— OFFICIAL. Concentrate C, under 45, to about 200 cc. ; add 2-3 grams of diammonium hydrogen phosphate and sufficient hydrochloric acid to clear the solution when the arnmonium phosphate is all dissolved; disodium hydrogen phosphate or sodium ammonium hydrogen phosphate may be used instead of the diammonium hydrogen phosphate. When cold, make slightly alkaline with ammonium hydroxid, stirring constantly. Add 1-2 cc. excess of ammonium hydroxid and allow to stand about 12 hours. Filter off the supernatant liquid and wash 3 or 4 times by decantation with a solution of 2.5% ammonium hydroxid. Dissolve the precipitate in hydrochloric acid, dilute to about 150 cc, add a little diammonium hydrogen phosphate and precipitate with ammonium hydroxid as before. Allow to stand 6-12 hours, filter, wai.?h free from chlorin, ignite, heat over a blast lamp, and weigh as magnesium pyrophosphate. (Cf. II, 16). Calculate to magnesium. Sulphuric Acid, Sodium, Potassium and Lithium. 48 sulphuric acid.— official. Make a preliminary examination, using 100-250 cc. of the water to determine the approximate quantity of sulphates. The alkali salts present can be approximated IV] WATERS 45 by calculating the amount of sodium necessary to combine with the excess of acids (hydrochloric, sulphuric, and bicarbonic) over the calcium and magnesium. Take a quantity, usually 1-5 liters, of the water suflficient to yield not more than 1 gram of barium sulphate and not more than 0.5 gram of mixed chlorids. Acidify with hydrochloric acid, evaporate to dryness in a platinum dish and remove silica by 2 evaporations as under 40, using not more than 2 cc. of hydrochloric acid (1 to 1) for the final solution. Combine the filtrate and washings from the silica determi- nations, and concentrate to about 150-200 cc. Heat to boiling and precipitate with alight excess of 10% barium chlorid solution, added very slowly and with constant stirring. Cover and allow to stand on the steam bath about 12 hours. Filter, wash thoroughly the precipitate of barium sulphate with hot water, dry, ignite over a Bunsen burner, and weigh. If the content of sulphate in the sample is unusually large proceed as far as the concentration of the silica filtrates as directed above. Add 50 cc. of concentrated hydrochloric acid, heat to boiling and precipitate with barium chlorid solution as before. Evaporate to dryness, wash the precipitate repeatedly by decantation and filter. Complete the washing of the precipitate; ignite and weigh. Calculate to the sulphuric acid ion. Designate the filtrate as E. 49 SODroM, POTASSIUM AND LITHIUM.— OFFICIAL. Evaporate to dryness £', under 48, in a platinum dish and ignite the residue to faint redness to remove all traces of ammonium salts. Dissolve the residue in the dish in about 200 cc. of water and precipitate with milk of lime or a solution of barium hydroxid. Boil, allow to stand 30 minutes, and filter off the insoluble magnesium hydroxid. Thoroughly wash the precipitate with hot water and combine the filtrate and washings. If the precipitate of magnesium is large, it is advisable to dissolve in a small amount of hydrochloric acid, evaporate to dryness, take up with water, and precipitate as before. Concentrate the 2 filtrates and washings to 200-250 cc. Add ammonium hj'droxid and sufficient ammonium carbonate solution to precipi- tate the calcium and barium. Allow to stand on a steam bath 1-2 hours. Filter off the supernatant liquid, dissolve the precipitate in hydrochloric acid, reprecipitate as above, and wash thoroughly with hot water. Evaporate the combined filtrates and washings to dryness and drive off the ammonium salts by gentle heat. Treat the residue with water; filter through a small filter, using as little wash water as possible; evaporate to a small volume and again precipitate with 1 or 2 drops of ammonium hydroxid and 2 or 3 drops of ammonium carbonate and oxalate. If any precipitate appears (which is usually not the case) filter and repeat the process. Evaporate the filtrate to dryness and drive off all ammonium salts by heating in platinum to faint redness. Treat the residue with a little water; filter into a small platinum dish; add a few drops of hydrochloric acid and evaporate to dryness. Dry in an oven, heat to faint redness, cool in a desiccator, and weigh the combined chlorids of potas- sium, sodium, and lithium. Repeat the heating to constant weight, (i). Dissolve the mixed chlorids in hot water; filter, and wash. Return the filter paper and residue to the dish, dry, ignite, and weigh, {y). The difference between (x) and {y) is the weight of the mixed chlorids. The determination of lithium is then made according to the method of Gooch.* Transfer the combined chlorids to a 50-100 cc. Erlenmeyer flask and evaporate the solution nearly, but not quite, to dryness. Add about 30 cc. of redistilled amyl alcohol. Connect the flask, the stopper of which carries a thermometer, using a condenser if desired, to avoid the escape of the irritating vapor of the amyl alcohol, and boil until the temperature rises approximately to the boiling point of amyl alco- 46 METHODS OF ANALYSIS [Chap. hoi (130°C.) to remove the water. Cool slightly and add a drop of hydrochloric acid to convert small amounts of lithium hydroxid to lithium chlorid. Connect with the condenser and repeat the boiling until the temperature reaches the boiling point of amyl alcohol to again drive off the water. The content of the flask at this time is usually 15-20 cc. Filter through a small paper or a Gooch crucible into a graduated cylinder and note the exact quantity of the filtrate, which determines the subsequent correction. Wash the precipitate with small quantities of amyl alcohol. Evapo- rate the filtrates and washings in a small platinum dish to dryness on the steam bath, dissolve the residue in water, and add a few drops of sulphuric acid. Evaporate on a steam bath and expel the excess of sulphuric acid by heating gently over a Bunsen burner until the carbonaceous matter is completely burned off, repeating the addi- tion of a few drops of sulphuric acid if necessary. Cool and weigh the dish and contents, (x). Dissolve in a small quantity of hot water, filter through a small filter, wash and return filter to dish; ignite and weigh, (y). The difference between (x) and iy) is the weight of impure lithium sulphate. The purity of the lithium sulphate should be tested by adding small amounts of ammonium phosphate solution and ammonium hydroxid, which will precipitate any magnesium previously present in the lithium sulphate. Any precipitate appearing after standing overnight should be collected on a small filter, ignited, weighed as magnesium pyrophosphate, calculated to sulphate and subtracted from the weight of the impure lithium sulphate. From this weight subtract 0.00113 gram of sodium and potassium sulphates for every 10 cc. of amyl alcohol filtrates, exclusive of the amyl alcohol used in washing the residue, on account of the solubility of sodium and potassium chlorids in amyl alco- hol. Calculate to lithium from the corrected weight of lithium sulphate. Dissolve the mixed chlorids from the flask and filter with hot water, evaporate to dryness, ignite gently to remove amyl alcohol, filter, and thoroughly wash; con- centrate the filtrates and washings to 25-50 cc. Transfer to a porcelain dish, add sufficient platinic chlorid solution [I, 40 (b)] to convert sodium and potassium to their respective double chlorids and evaporate to dryness. Treat the residue with 80% alcohol, filter, and wash until the excess of platinic chlorid and sodium platinic chlorid has been removed. Dry the filter and precipitate, dissolve the residue in hot water, and transfer to a weighed platinum dish. Evaporate on the steam bath, dry for 30 minutes in the oven at 100°C. and weigh as potassium platinic chlorid; calculate to potassium chlorid. To the weight of potassium chlorid add 0.00051 gram for every 10 cc. of amyl alcohol used in the extraction of the lithium chlorid, which corrects for the solubility of the potassium chlorid in amyl alcohol. Calculate to potassium. The weight of sodium chlorid is found by subtracting the combined corrected weights of lithium chlorid and potassium chlorid from the total weight of the 3 chlorids. Calculate the sodium chlorid to sodium. PHOSPHORIC ACID.— OFFICIAL. 50 REAGENTS. The reagents used are described under I, 7. 51 DETERMINATION. Treat 500 cc. of the water, or a larger amount if necessary, with about 10 cc. of concentrated nitric acid and evaporate in a porcelain dish nearly to dryness to drive off hydrochloric acid. Treat the residue with water and filter, if necessary. Add ammonium hydroxid to alkalinity and then just enough nitric acid to restore acidity. rV] WATERS 47 Add some solid ammonium nitrate and heat in the water bath at a temperature of 45*-50°C. Add the molybdate solution and keep at the above temperature for 30 minutes. The yellow precipitate formed at this point appears generally only in traces; if more than traces are present, filter and wash with cold water until entirely free from nitric and molybdic acids. Transfer the precipitate and filter to a beaker, add a little water, and beat the paper and contents to a pulp. Dissolve the yellow precipitate in a small amount of the standard potassium hydroxid ; add phenolphtha!- ein and titrate with the standard acid. From the data so obtained calculate the phosphoric acid ions in the water to milligrams per liter. 52 Manganese. Iodin, Bromin, Arsenic and Boric Acid. Evaporate large quantities of water to dryness, after the addition of small amounts of solid sodium carbonate. Boil the residue thus obtained with water, transfer to a filter, and wash thoroughly with hot water. Make the alkaline filtrate up to a definite volume. MANGANESE.— OFFICIAL. 53 REAGENTS. (a) Dilute nitric acid {1 to 1). (b) 0.2% silver nitrate solution. (C) Ammonium persulphate. (d) Standard manganous sulphate solution. — Dissolve 0.2877 gram of pure potas- sium permanganate in a small amount of water, add an excess of sulphuric acid, reduce carefully with oxalic acid and make up to 1 liter. One cc. of this solution is equivalent to 0.1 mg. of manganese. 54 DETERMINATION. Dissolve the insoluble residue under 52 in an excess of the dilute nitric acid, evap- orate to dryness, treat with water, add about 1 cc. of strong nitric acid and a little of the silver nitrate. If a precipitate of silver chlorid appears, add more of the silver nitrate until all the chlorin is precipitated. Add an excess of about 10 cc. of the silver nitrate for each mg. of manganese present in the sample. Filter, add 1 gram of ammonium persulphate to the filtrate, and place the beaker or flask con- taining the solution on the steam bath until a pink color develops (usually about 20 minutes). Compare the color developed with standards similarly prepared by treat- ing solutions containing known amounts of the standard manganous sulphate with nitric acid, silver nitrate, and ammonium persulphate. IODIN AND BROMIN.— TENTATIVE. 55 REAGENTS. (a) 10% sodium hydroxid solution. (b) Sulphuric acid {1 to 5). (C) ;?% potassium, or sodium nitrite solution. (d) Carbon disulphid.— Freshly purified by distillation. (e) Chlorin water. — Saturated and freshly prepared. 56 DETERMINATION. Evaporate to dryness an aliquot of the alkaline filtrate under 52, add 2-3 cc. of water to dissolve the residue and enough 95% alcohol to make the percentage of alcohol about 90. This precipitates the chlorids. Heat to boiling, filter and repeat the preceding solution and precipitation once or twice. Add 2 or 3 drops of the 48 METHODS OF ANALYSIS [Chap. sodium hydroxid to the combined alcoholic filtrates and evaporate to dryness. Dis- solve this last residue in 2-3 cc. of water and repeat as above described the precipi- tation with alcohol, heating, and filtering. Add a drop of the sodium hydroxid to this alcoholic filtrate and evaporate to dryness. Dissolve this residue in a little water, acidify with the sulphuric acid, using 3 or 4 drops in excess, and transfer to a small flask. Add 4 drops of the potassium nitrite and about 5 cc. of the carbon disulphid. Shake until all the iodin is extracted, filter off the acid solution from the carbon disulphid, retaining the latter in the flask. Wash the flask, filter and con- tents with cold water and transfer the carbon disulphid (containing the iodin in solution) to a Nessler tube, using approximately 5 cc. of the carbon disulphid. In washing the filter make the contents of the tube up to definite volume, usually 12-15 cc, and compare the color with that of other* tubes containing known amounts of iodin dissolved in carbon disulphid. Prepare these standard tubes by treating measured quantities of a solution of known potassium iodid content as described above. Transfer the sample and standards, from which the iodin has been removed, severally to small flasks. To the standards add definite measured quantities of a bromid solution of known strength, and to each of the flasks containing sample and standards add 5 cc. of purified carbon disulphid. Add the saturated chlorin water, 1 cc. at a time, shaking after each addition until all the bromin is set free. (Avoid a large excess of chlorin, since a bromo-chlorid may be formed which spoils the color reaction.) Filter off the water solution from the carbon disulphid through a mois- tened filter, wash the contents of the filter 2 or 3 times with water, and then transfer to a Nessler tube by means of about 1 cc. of carbon disulphid. Repeat this extrac- tion of the filtrate twice, using 3 cc. of carbon disulphid each time. The combined carbon disulphid extracts usually amount to 11.5-12 cc. Add enough carbon di- sulphid to the tubes to bring them to a definite volume, usually 12-15 cc, and com- pare the sample with the standards. In some cases when using this method near its upper limit the amounts of carbon disulphid recommended do not extract all the bromin. In these cases, make 1 or 2 extra e.xti'actions with carbon disulphid, trans- fer the extracts to another tube, and compare the color with some of the lower standards and add the readings thus obtained to the others. Results closely approximating the true values for iodin and bromin can be ob- tained on most samples by omitting the extractions with alcohol given above and by comparing the color of the carbon disulphid solutions directly in the extraction flasks, thus shortening the method. ARSENIC-OFFICIAL. 57 REAGENTS. (a) Zinc, arsenic-free. (b) Sulphuric acid (1 to 5), arsenic-free. (C) Standard arsenious oxid solution. — Dissolve 0.0132 gram of pure arsenious oxid in 100 cc. of water containing about 50 mg. of sodium carbonate. One cc. of this solution is equivalent to 0.1 mg. of As. DETERMINATION. 58 Evaporate to dryness an aliquot of the alkaline filtrate under 52. Acidify with the sulphuric acid and subject to the action of the zinc and the sulphuric acid in a Marsh-Berzclius apparatus. Compare the mirror obtained with a mirror prepared from an arsenious oxid solution of known strength. Calculate to the arsenic acid rVJ WATERS 49 BORIC ACID.— OFFICIAL. (Glassware containing boron must not be used in this determination.) 59 DETERMIN.\TIOX. Qualitative test. — Evaporate to dryness a part of the alkaline filtrate under 52, treat with 1-2 cc. of water, and slightly acidify with dilute hydrochloric acid (1 to 1). Add about 25 cc. of 95% alcohol, boil, filter, and repeat the extraction of the residue. Make the filtrate slightly alkaline with sodium hydroxid solution and evaporate to dryness. Add a little water, slightly acidify with dilute hydrochloric acid, and place a strip of turmeric paper in the liquid. Evaporate to dryness on the steam bath and continue the heating until the turmeric paper is dry. If boric acid is present the turmeric paper takes on a cherry-red color. As a confirmatory test, apply a drop of dilute ammonium hydroxid to the reddened paper, and a dark olive color will be due to boric acid. Quantitative test. — It is not usually necessary to determine boric acid quantita- tively. However, if it is necessary, the Gooch method^ is used. 60 METHOD OF REPORTING RESULTS.— TENTATIVE. Report the bases and acids as positive and negative ions in milligrams per liter, except in the case of silica, which report as such without considering how much is present as the silicic acid ion and how much as free silica. Report iron and alumin- ium together when present in unimportant quantities, and in calculations consider it as iron. When iron and aluminium are present in larger quantities make the separation and report each separately. In calculating the hypothetical combinations of acid and basic ions join sodium to nitrous, nitric, metaboric and arsenic acids; potassium to iodin and bromin; calcium to phosphoric acid. Assign the residual basic ions in the following order; ammonium, lithium, pota.ssium, sodium, magnesium, calcium, strontium, manganese, iron and aluminium — to the residual acid ions in the following order: Chlorin, sulphuric acid ion, carbonic acid ion, and bicarbonic acid ion. In case the bicar- bonic acid ion is not present in a sufficient quantity to join with all the calcium, the residual calcium is joined to silica to form calcium silicate, and manganese, iron, and aluminium are calculated to the oxids MusO^, Fe20j, and AI2O3, respectively. INDUSTRIAL WATER. 61 SOLIDS IN SOLUTION.— OFFICIAL. Determine as directed under 7. 62 CHLORIN.— OFFICIAL, Determine as directed under 19. 63 COMBINED CARBONIC AND BICARBONIC ACIDS.-OFFICLAL. Determine as directed under 39. 64 NITRATES.-OFFICLAL. Determine as directed under 15 or 17. 65 SILICA.-OFFICLAL. Determine as directed under 40. Generally one evaporation with hydrochloric acid for removal of silica is sufficient. 50 METHODS OF ANALYSIS [Chap. Q6 IRON AND ALUMINIUM.— OFFICIAL. Determine as directed under 41 . 67 CALCIUM.— OFFICIAL. If no phosphoric acid is present, concentrate the filtrate from the determination of iron and precipitate with ammonium hydroxid and oxalate as directed under 45. Usually one precipitation is sufficient. $8 MAGNESIUM.— OFFICIAL. Determine as directed under 47. 69 SULPHURIC ACID AND ALKALIES. -OFFICIAL. Follow the methods described under 48 and 49. Generally, however, for tech- nical purposes it is sufficiently accurate to determine the acids and the bases, except sodium and potassium, and then to calculate the excess of acid over basic ions to the sodium salt, and state the alkali thus found as sodium and potassium by difference. 70 TEMPORARY HARD NESS. 7— TENTATIVE. The difference between the alkalinity after boiling, 74, and the alkalinity before boiling, 72, is the temporary hardness in parts per million of calcium carbonate. ALKALINTTY-Before BoiUng. 71 REAGENTS. (a) N /50 sulphuric acid. (b) Erythrosin indicator. — Dissolve 0.1 gram of the sodium salt in 1 liter of water. (C) Chloroform. — Neutral to erythrosin. 72 DETERMINATION. Measure 100 cc. of the water into a 250 cc. white, glass-stoppered bottle, add 2.5 cc. of the erythrosin and 5 cc. of the chloroform, add X/50 sulphuric acid in small quanti- ties, shaking the bottle vigorously after each addition of the acid. The rose color gradually disappears and is finally discharged by 1 or 2 drops of the acid. A white paper held back of the bottle facilitates the detection of the end point. Multiply the number of cc. of N/50 sulphuric acid used by 10 to obtain the number of parts per million of alkalinity in terms of calcium carbonate. ALKALINTTY-After BoUing 73 REAGENTS. Described under 71 . 74 DETERMINATION. Boil 100 cc. of the water in a porcelain dish gently for 30 minutes. Cool, transfer to a 100 cc. volumetric flask and fill to the mark with recently boiled and cooled water. Filter through a dry paper and determine the alkalinity of the filtrate as directed under 72, making the proper calculation for the aliquot employed and cal- culating in terras of calcium carbonate the parts per million of alkalinity after boiling. IV] WATERS 51 TOTAL HARDNESS."— TENTATIVE. 75 REAGENTS. (a) Soda reagent. — Prepare a N/10 alkali solution, using equal parts of sodium hydroxid and sodium carbonate. Standardize the solution by titration against N/20 sulphuric acid, using erythrosin as indicator. 76 DETERMINATION, Add sufficient N/20 sulphuric acid to 200 cc. of the sample to neutralize the alkalin- ity, the amount required for this purpose being calculated from the results obtained as directed under 72. Concentrate to 100 cc, add 25 cc. of the soda reagent, and again boil down to 100 cc, using a porcelain, silver, or platinum dish. Cool, rinse into a 200 cc. volumetric flask and dilute to 200 cc. with freshly boiled and cooled water. Filter through a dry paper, reject the first 50 cc. of the filtrate, and titrate 100 cc. of the filtrate, using N/20 sulphuric acid and chloroform with erythrosin as indicator, as directed under 72. Calculate the total hardness by the following formula: H = 12.5 (S-2N) in which H = total hardness expressed as parts per million of calcium carbonate. S = number of cc. of N/20 sulphuric acid equivalent to the 25 cc. of the soda reagent used. N = number of cc. of N/20 sulphuric acid used in titrating back the excess of the soda reagent. 77 PERMANENT OR NON-CARBONATE HARDNESS.— TENTATIVE. The difference between the alkalinity before boiling 72 and the total hardness 76 is the permanent or non-carbonate hardness expressed as parts per million of cal- cium carbonate. IRRIGATING WATER. 78 GENERAL METHODS.— OFFICIAL. Determine the solids in solution, chlorin, carbonic and bicarbonic acids, sulphuric acid, calcium and magnesium as directed under 7, 19, 39, 48, 45, and 47 respec- tively. To make the hypothetical combination, calculate calcium and magnesium to the acid ions in the following order: bicarbonic, sulphuric and chlorin. Then calculate the remaining acid ions, including carbonic, to the corresponding salts of sodium. BLACK ALKALI.— OFFICIAL. 79 REAGENTS. (a) N'/50 sodium carbonate. — One cc. of this solution is equivalent to 0.00106 gram of sodium carbonate. (b) N/50 sulpJmric acid. — One cc. of this solution is equivalent to 0.0010 gram of calcium carbonate or 0.00136 gram of calcium sulphate. (C) Enjihrosin indicator. — Dissolve 0.25 gram of the sodium salt in 1 liter of water, (d) Chloroform. — Neutral to erythrosin. 80 DETERMINATION. Transfer 200 cc. of the water to a platinum or silver dish, add 50-100 cc. of N/50 sodium carbonate, according to the amount of soluble salts of calcium and magnesium present, and evaporate to dryness. Rub up the residue with carbon dio-xid-free water. 52 METHODS OF ANALYSIS For this purpose distilled water should be vigorously boiled until approximately one third of the original volume is evaporated, then cooled and stoppered. An ordinary laboratory wash bottle should not be used to transfer the residue, as the carbon dioxid from the breath of the operator is sufficient to vitiate the results. Transfer to a 100 cc. graduated flask, make up to the mark, shake thoroughly, and allow to stand until clear (12-15 hours). Remove 50 cc. of the clear, supernatant liquid, equivalent to one half of the original quantity of water and sodium carbonate added, and transfer to a stoppered titrating bottle, of 250 cc. capacity, of clear glass without any tinge of pink. Add 5 cc. of the chloroform and 1 cc. of the erythrosin and titrate with the standard acid until the color disappears. Shake the solution vigorously after each addition of the acid; the chloroform produces a milkj^ appear- ance which makes the reading of the end point sharp and certain. (1) If less sulphuric acid is required than is equivalent to one half of the sodium carbonate added, due to some of the sodium carbonate reacting with soluble salts of calcium and magnesium, the solution originally contained no black alkali in excess but rather an excess of the so-called permanent or non-carbonate hardness. It is customary to express the hardness in terms of calcium carbonate or calcium sul- phate. With irrigating waters the latter form is to be preferred. Therefore, the difference between the number of cc. of the sulphuric acid required and one half of the number of cc. of the sodium carbonate added multiplied by the factor 0.00136 gives the equiA^alent of calcium sulphate in 100 cc. of the water. (2) If more sulphuric acid is required than that equivalent to one half of the sodium carbonate added, black alkali was originally present in the solution and the difference in cc. multiplied by the factor 0.00106 gives the black alkali in terms of sodium carbonate in 100 cc. of water. BIBLIOGRAPHY. 1 Fresenius. Quantitative Chemical Analysis. Revised and amplified trans- lation of the 6th German ed., 1906, 2: 204. 2 Ber., 1888, 21: 2843; Rept. Mass. State Board of Health, 1890, 2: 722. » J. Am. Chem. Soc, 1911, 33: 362; Standard Methods of Water Analysis. Am. Pub. H. Assoc, 2nd ed., 1912, pp. 61 and 62. « Sutton. Volumetric Analysis, 10th ed., p. 303; Analyst, 1901, 26: 141, 5 Am. Chem. J. 1887, 9: 33; U. S. Geol. Surv. Bull. 422, 175. «Am. Chem. J. 1887,9: 23. ^ Standard Methods of Water Analysis. Am. Pub. H. Assoc, 2nd ed.. 1912. dd. 36 and 37. > , , ff » Ibid, pp. 40 and 41. i V. TANNING MATERIALS.— TENTATIVE. EXTRACTS. 1 PREPARATION OF SOLUTION. (a) Solid extracts. — Grind solid extracts in a large porcelain mortar, so that the material will pass through a 10 mesh sieve, mix thoroughly and weigh out a quantity containing 3.75-4.25 grams of tannin. This shouldbedone as rapidly as possible to avoid change in moisture content. Pour into 100 cc. of water at 85''C., place on a steam bath and stir until a homogeneous solution is obtained. Transfer to a 1 liter flask with 800 cc. of water at 85°C. Cool rapidly to 20°C. and make up to 1 liter. (b) Fluid extracts. — Allow fluid extracts to come to room temperature and mix thoroughly. Weigh out rapidly a quantity containing 3.75-4.25 grams of tannin. Dissolve by washing into a 1 liter flask with 900 cc. of water at 85°C. Cool rapidly to 20°C. and make up to 1 liter at 20°C. After the preparation of the solutions, proceed at once with the analj'sis. 2 TOTAL SOLIDS. Thoroughly' mix the prepared solution, pipette at once 100 cc. into a tared flat- bottomed glass dish, 2|-3 inches in diameter, and (1) evaporate and dry for 16 hours in a combined evaporator and dryer' at 98°-100°C. ; or, (2) after evaporating on the steam bath, dry for 12 hours on the bottom of a water oven at 98°-100°C. Remove immediately to desiccators containing sulphuric acid (place no more than 2 dishes in 1 desiccator) and weigh rapidlj' when cooled. Calculate the percentage of total solids. SOLUBLE SOLIDS. 3 PREPARATION OF FILTER. The kaolin used should be neutral to phenolphthalein and should not yield more than 1 mg. of soluble solids per 100 cc. of filtrate of a 1% suspension after an hour's digestion at 20°C. Dry on a water bath and preserve in a tightly stoppered bottle. Add about 75 cc. of the solution, as prepared under 1 , to 1 gram of the kaolin in a beaker. Stir and pour immediately into a single, 15 cm. No. 590, S. & S. folded filter. Return the filtrate to the paper when approximately 25 cc. have run through, repeat the operation for an hour, thus transferring all the kaolin to the paper. At the end of an hour, discard the solution on the filter by siphoning it off, disturbing the kaolin as little as possible. 4 DETERMINATION. Bring about 150 cc. of the original solution, as prepared under 1 , to exactly 20°C. Fill the filter, prepared as under 3, with this solution and discard the filtrate until it runs through clear. Keep the filter full, the temperature of the filtering solution at 20°-25°C., and the funnel and receiving vessel covered. Pipette at once 100 cc. of the clear filtrate into a tared dish, evaporate and dry as directed under 2. Calculate the percentage of soluble solids. 53 54 METHODS OF ANALYSIS [Chap. 5 INSOLUBLE SOLIDS. The difference between the percentage of the total solids and the percentage of soluble solids is the percentage of the substance insoluble in water at 20''-25°C. NONTANNINS. 6 REAGENTS. Hide powder. — This should be of woolly texture, well delimcd, and 10 grams of the water-free powder should require 12-13 cc. of N/10 sodium hydroxid to neutralize it. Calculate the amount of air-dry hide powder which will be required for the number of determinations to be made, on a basis of 13 grams of air-dry hide powder for each determination. Increase this calculated amount by 35 grams of dry hide powder to provide a sufficient amount for all the determinations. Thoroughly digest the total amount of hide powder with 10 times its weight of water. Then for each gram of the hide powder, so digested, add 1 cc. of 3% chrome alum solution; and either agitate frequently for several hours and let stand overnight or agitate in some form of mechanical shaker for an hour. Transfer to a strong linen filter and squeeze thoroughly. Remove from the filter and digest for 15 minutes with a quantity of water equivalent to 15 times the weight of the dry hide powder employed. Filter and squeeze to approximately 73% of water, using a press if necessary. Very strong pressure is required to reduce the water content below 70%. Repeat the digestion and filtration 3 times. Determine moisture in 20 grams of the squeezed hide powder as directed under 2. 7 DETERMINATION. Place 46 grams of the wet hide powder in a suitable container of about 300 cc. capacity, add 200 cc. of the tanning solution, as prepared under 1, and shake for 10 minutes in a mechanical shaker. Squeeze immediately through linen, add 2 grams of kaolin, as used under 3, to the filtrate which contains the nontannins, stir, and filter through a single, folded 18.5 cm. filter paper (No. IF. Swedish, preferred), refiltering until the filtrate is clear. The filtrate should give no precipitate with a gelatin-salt solution (1% gelatin and 10% salt). Pipette 100 cc. of the filtrate into a tared dish and evaporate as directed under 2. Correct the weight of the nontannin residue for the dilution caused by the water retained in the wet hide powder. Cal- culate the percentage of nontannins. 8 TANNIN. The difference between the percentage of the solu})le solids and the percentage of nontannins is the percentage of tannin. DETECTION OF SULPHITE-CELLULOSE. 9 REAGENTS. Siilphile-celtulose solution. — Dissolve 0.5 gram of the total solids, derived from sulphite-cellulose, in 1 liter of water.and add sufficient tanning material, free from sulphite-cellulose, to give a concentration of 3.75-4.25 grams of tannin per liter. 10 DETERMINATION. Place 5 cc. of the tanning solution, prepared as under 1 , in a test tube; add 0.5 cc. of anilin and shake well; then add 2 cc. of concentrated hydrochloric acid and mix again. Compare the precipitate formed with that produced when the above sul- V] TANNING MATERIALS 55 phite-cellulose solution is similarly treated. Sulphite-cellulose is held to be present, in the predetermined absence of the synthetic tanning material, Neradol-D, if the precipitates are approximately equivalent in amount. LIQUORS. 11 PREPARATION OF SOLUTION. Dilute the liquor with water at room temperature to contain approximately 0.7 gram of solids in 100 cc. of solution. If the liquor does not give a proper solution with water at room temperature, it may be diluted with water at 80°C., and then cooled rapidly to 20''C. 12 TOTAL SOLIDS. Proceed as directed under 2. 13 SOLUBLE SOLIDS. Proceed as directed under 4. 14 NONTANNINS. Proceed as directed under 7, using the amount of wet chromed hide powder which will give the ratio between the tannin and hide powder shown in the following table: TANNIN RANGE PER 100 cc. DRT HIDE POWDER PER 200 CC. gram 0.35—0.45 0.25—0.35 0.15—0.25 0.00—0.15 grams 9.0—11.0 6.5— 9.0 4.0— 6.5 0.0- 4.0 TOTAL ACIDITY. 1 5 REAGENTS. (a) Hematin solution.— Digest 0.5 gram of hematin in 100 cc. of cold neutral 95% alcohol. (b) Gelatin solution. — Dissolve 10 grams of gelatin in hot water, cool, add 25 cc. of 95% alcohol and dilute. If the gelatin solution is acid or alkaline, neutralize with N/10 sodium hydroxid or N/10 acetic acid, respectively, using hematin solution as indicator and make up to 1 liter. (C) Kaolin. — Digest with dilute hydrochloric acid; wash and dry as under 3. (d) N/IO sodium hydroxid. 16 DETERMINATION. Add 25 cc. of the gelatin solution to 25 cc. of the tanning liquor in a stoppered cylinder, dilute with water to 250 cc, add 15 grams of the kaolin and shake vigorously. Allow to settle for at least 15 minutes, remove 30 cc. of the supernatant liquid, dilute with 50 cc. of water and titrate with N/10 sodium hydroxid, using the hematin solu- tion as indicator. Each cc. of N/10 sodium hj'droxid is equivalent to 0.2 % acid, calculated as acetic, in the liquor. 56 METHODS OF ANALYSIS [Chap. 17 RAW AND SPENT MATERIALS. (Under raw materials are included woods, barks, leaves, etc.) MOISTITRE IN SAMPLE AS RECEIVED. Cut or break up large pieces and mix the sample rapidly to avoid change in mois- ture content. Dry as directed under 2, a suitable weighed quantity, dependent upon the physical condition and moisture content of the sample. 18 PREPARATION OF SAMPLE. Dry the remainder of the sample at a temperature not above 60°C. and grind to pass through a 20 mesh sieve. 19 MOISTURE IN PREPARED SAMPLE. Take 10 grams of the sample prepared in 1 8, dry as directed under 2, and calculate all results to an "as received", "air dry", or "moisture free" basis as desired. 20 EXTRACTION. FIG. 4. METAL EXTRACTOR USED FOR EXTRACTING TANNING MATERIALS. (For spent materials approximate the follov/ing quantities as closely as possible.) Place a quantity of the dried sample, containing 3.75-4.25 grams of tannin, in a beaker and wet thoroughly with hot water. Place a perforated porcelain plate in a tin-lined copper extractor of the general form shown in Fig. 4, and on the plate place a layer of cotton and wet thoroughly with water. Connect the extractor with an 800 cc. Erlenmeyer flask (G), open the stock-cock (E) and close the outlets (C) and (D). Pour into the extractor the material to be extracted, washing it into the extractor with hot water. Return the percolate through the extractor until it is practically clear. Place a layer of cotton on top of the material. Close the stop- cock (E), connect with an 800 cc. Erlenmeyer flask containing about 650 cc. of water, connect (D) by a delivery tube wuth a liter graduated collecting flask, return the total percolate to the extractor and connect by means of the metal cap (B) with a block tin condenser (A) in such a way that the condensate will drip upon the layer of cotton. Boil the water in the flask, and collect 400-500 cc. of percolate from the side tube (D). Open the stop-cock (E) and close the side tube (D), add water to the flask (G), if necessary, until it contains about 200 cc. Continue the extraction with water at steam heat, allowing the percolate to run back into the boiling flask. Re- V] TANNING MATERIALS 57 peat with 2 successive portions (150-250 cc. each) of water for a total of 14 hours, heating at such a rate that approximately 330 cc. of water will be condensed per hour. Combine all the extracts in the graduated liter flask in which the first per- colate was received. Heat to 80°C., cool, and make up to the mark. 21 ANALYSIS OF THE EXTRACT. Proceed as directed under 2—8, inclusive. If more dilute solutions than the directions specify are employed in the determination of nontannins, the amount of hide powder used is reduced, as directed under 14. BIBLIOGRAPHY. 1 J. Am. Leather Chem. Assoc, 1906, 1: 32. VI. LEATHERS.— TENTATIVE. VEGETABLE TANNED LEATHER. 1 PREPARATION OF SAMPLE. Grind the sample, without undue heating, and pass through a 10 mesh sieve. The ground sample must not contain hard lumps. Plane heavily greased leathers (con- taining more than 20 % fat) into very thin shavings. Spread out the prepared sample an! allow it to return to atmospheric moisture condition; mix thoroughly, and place in tightly covered containers. 2 MOISTURE. Place 10 grams of the sample, as prepared under 1 , in a tared, wide, shallow, weigh- ing bottle (or a similar dish which can be covered tightly), and dry in a water oven for 15 hours at 98^-100°C. Cover the weighing bottle, cool in a desi cator containing sulphuric acid, and weigh. The moisture present in the leather as received may be determined by cutting it quickly into small pieces and drying without grinding as directed above. 3 TOTAL ASH. Incinerate slowly 5 grams of the sample, as prepared under 1 , at a dull red heat. If difficulty is experienced in burning off the carbon, leach the residue with hot water, filter on an ashless filter, dry and ignite the filter and residue, add the filtrate, evaporate to dryness and ignite. Cool in a desiccator containing sulphuric acid and weigh. The ash may be examined for acids and bases by any suitable method. Alumin- ium, magnesium, sodium, barium, calcium and lead are the bases, and hydrochloric and sulphuric acids are the acids which it may be necessary to determine. 4 INSOLUBLE ASH. Incinerate slowly the residue from the extraction of water-soluble material, ob- taine I in 6 or 7, until all the carbon is burned off, cool in a desiccator containing sulphuric acid and weigh. 5 FATS. Place, without packing, 15 grams of the leather, as prepared under 1 , in a Soxhlet or Johnson extractor with a layer of fat-free cotton above and below the sample. Extract 8-10 hours with petroleum ether distilling between 50° and 80°C. Heavily greased leathers (containing 15% or more fat) will require the maximum time. Re- move the receiving flask, evaporate the petroleum ether on the stc am bath and dry the fat residue for 3 hours in a water oven at 98°-100°C., cool in a desiccator and weigh. Repeat the drying in the water oven for periods of l-U hours, cooling and weighing as before, until no further loss in weight occurs. Retain the leather residue from the fat extraction for the extraction of water-soluble material in 6 or 7. EXTRACTION OF WATER-SOLUBLE MATERIAL. 6 Method I. Evaporate the petroleum ether from the fat-free leather, obtained under 5, and moisten thoroughly with from 100-150 cc. of water. Place a layer of cotton in the 59 60 METHODS OF ANALYSIS [Chap. bottom of a Soxhlet extractor designed for making extractions at temperatures be- low 100°C. An extractor of this kind is furnished with a water jacket surrounding that por- tion of the apparatus containing the sample but does not enclose the side tube which carries the hot vapors to the condenser. Transfer the moistened fat-free leather to the extractor, and cover this with another layer of cotton to avoid siphoning off solid particles. Maintain the tempera- ture of the jacket surrounding the Soxhlet at 50°C. (1) Pour 200 cc. of water (in- cluding that used in moistening the leather) into the Soxhlet and allow it to siphon into the flask below, then heat and extract for an hour. Remove the flame and trans- fer the extract to a liter graduated flask. Then add water and continue the ex- traction as directed below, removing and transferring the extract to the liter flask before each fresh addition of water. (2) Add 175 cc. of water and extract for 2 hours. (3) Add 175 cc. of water and extract for 3 hours. (4) Add 175 cc. of water and extract for 4 hours. (5) Add 175 cc. of water and extract for 4 hours. Transfer the last portion of the extract to the graduated flask. This gives 14 hours' extraction and an extract which does not exceed 1 liter in volume. Dilute to 1 liter at room temperature and mix thoroughly. 7 Method 11. (This method is the same in principle as the official method of the American Leather Chemists Association. i) Digest overnight 30 grams of the fat-free leather, obtained under 5, in approxi- mately 200 cc. of water. Transfer the leather and extract to a percolator. Continue the extraction by percolating with water at 50°C. Collect 2 liters of percolate, regulating the flow of water at such a rate that 2 liters will be collected in 3 hours. Dilute to volume at room temperature and mix thoroughly. To the extract, prepared according to 6 or 7, add a few drops of toluol to prevent fermentation of sugars, and reserve for the determination of glucose, total solids, soluble solids, and nontannins. O PREPARATION OP SOLUTION. To 200 cc. of the leather extract, as prepared under 6 or 7, add 25 cc. of a saturated solution of normal lead acetate, mix thoroughly, and filter at once through a dry, plaited paper, returning the first portions of the filtrate to the filter until the fil- trate becomes clear. Keep the containers and the funnel covered during these opera- tions. Without waiting for the entire filtrate to run through add 10-12 grams of solid potassium oxalate, shake frequently during 15-20 minutes and filter through a dry, plaited paper returning the "first runnings to the filter until the filtrate runs clear. Pipette 150 cc. of the last filtrate into a 600 cc. Erlenmeyer flask, add 5 cc. of concentrated hydrochloric acid and boil under a reflux condenser for 2 hours. Cool, neutralize with solid sodium carbonate, using a little phenolphthalein as indicator, transfer to a 200 cc. volumetric flask and complete to volume with water. Filter through a double filter, and return the first runnings until the filtrate becomes perfectly clear. Determine the dextrose in the filtrate immediately. VI] LEATHERS 61 9 DETEKMINATION. Determine dextrose in 50 cc. of the solution, as prepared under 8, equivalent to 0.5 gram of leather, according to VIII, 25 and express the result as glucose. I 0 TOTAL SOLIDS. Determine as directed under V, 2. I I SOLUBLE SOLIDS. Determine as directed under V, 4. 1 2 NONTANNINS. Determine as directed under V, 7. 1 3 SOLUBLE TANNIN. The difference between the percentage of the soluble solids and the corrected nontannins is the percentage of tannin. 1 4 NITROGEN. Determine as directed under I, 21 . 1 5 HIDE SUBSTANCE. Multiply the percentage of nitrogen by 5.62. The result will be the percentage of hide substance present. 16 COMBINED TANNIN. Deduct the sum of the percentages of moisture, under 2, insoluble ash, under 4, soluble solids, under 1 1 , and hide substance, under 1 5, from 100. The result will be the percentage of combined tannin. BIBLIOGRAPHY. » J. Am. Leather Chem. Assn., 1915, 10: 122. VII. INSECTICIDES AND FUNGICIDES. GENERAL METHOD. 1 PREPARATION OF SAMPLE.— TENTATIVE. Mix thoroughly all samples before analysis. Make water-soluble arsenic deter- minations on samples as received without further pulverization or drying. In the case of lye, sodium cyanid or potassium cyanid, weigh large quantities in weigh- ing bottles and analyze aliquots of the aqueous solutions. PARIS GREEN. 2 MOISTURE.— TENTATIVE. Dry 2 grams at 105°-110°C. for 5 hours and express the loss in weight as moisture. TOTAL ARSENIC.!— OFFICIAL. (Arsenic, present as arsenate, is titrated as arsenious oxid.) 3 REAGENTS. (a) Starch indicator . — Mix about 0.5 gram of finely powdered potato starch with cold water to a thin paste; pour into about 100 cc. of boiling water. (b) Standard arsenious oxid solution. — Dissolve 2 grams of pure arsenious oxid in a beaker by boiling with about 150-200 cc. of water containing 10 cc. of concen- trated sulphuric acid, cool, transfer to a 500 cc. graduated flask and dilute to the mark. (C) Standard iodin solution. — Prepare an approximately N/20 solution as fol- lows: Mix intimately 6.35 grams of pure iodin with twice its weight of pure potas- sium iodid. Dissolve in a small amount of water, filter and dilute the filtrate to 1 liter in a liter graduated flask. Standardize against (b) as follows: Pipette 50 cc. of the arsenious oxid into an Erlenmeyer flask, dilute to about 400 cc, neutralize with sodium bicarbonate, add 4-5 grams in excess, and add the standard iodin solu- tion from a burette, shaking the flask continuously, until the yellow color disap- pears slowly from the solution, then add 5 cc. of the starch indicator and continue adding the iodin solution, drop by drop, until a permanent blue color is obtained. Calculate the value of the standard iodin solution in terms of arsenious oxid \As2Os) and arsenic oxid (AS2O5). Occasionally restandardize the iodin against freshly prepared arsenious oxid solution. 4 APPARATUS. The apparatus used is shown in Fig. 5. The distillation flask rests on a metal gauze which fits over a circular hole in a heavy sheet of asbestos board. The first 2 Erlenmeyer flasks are of 500 and 1000 cc. capacity and contain about 40 and 100 cc. of water, respectively. Both of these flasks should be placed in a pan and kept surrounded with cracked ice and water. The third flask, containing a small amount of water, is used as a trap. 64 METHODS OF ANALYSIS [Chap. 3 DETERMINATION. Weigh an amount of the sample equal to the arsenious oxid equivalent of 250 cc. of the standard iodin solution, and wash into the distillation flask by means of 100 cc. of concentrated hydrochloric acid (sp. gr. 1.19). Add 5 grams of cuprous chlorid (Cu2Cl2) and distil. When the volume in the distillation flask is reduced to about 40 cc, add 50 cc. of concentrated hydrochloric acid by means of the dropping funnel and continue the distillation until 200 cc. of the acid distillate have passed over. Then wash down the condenser and all the connecting tubes carefully, transfer these washings and the contents of the 3 Erlenmeyer flasks to a liter graduated flask and dilute to the mark. Mix thoroughly, pipette 400 cc. into an Erlenmeyer flask and nearly neutralize with a saturated solution of sodium or potassium hydroxid, using a few drops of phenolphthalein as an indicator, keeping the solution well cooled. Continue as directed under 3 (C) beginning with "neutralize with sodium bicar- bonate." The number of cc. of iodin used in this titration represents directly the total per cent of arsenic in the sample expressed as arsenious oxid (AsjOa). FIG. 5. APPARATUS FOR DISTILLATION OF ARSENIC CHLORID. TOTAL ARSENIOUS OXID. (The following methods determine arsenic, and antimony if present, as the -ous oxids, AS2O3 and Sb203, respectively. Ferrous and cuprous salts vitiate the results.) Method I. C. C. Hedges Method,^ Modified.^— Tentative. 6 REAGENTS. The reagents and solutions used are described under 3. 7 DETERMINATION. Weigh an amount of the sample equal to the arsenious oxid equivalent of 100 cc. of the standard iodin solution, wash into an Erlenmeyer flask with 10-15 cc. of dilute hydrochloric acid (1 to 1), followed by about 100 cc. of water, and heat on the steam- bath to complete solution, at a temperature not exceeding 60°C. Cool, neutralize VII] INSECTICIDES AND FUNGICIDES 65 with sodium bicarbonate, add 4-5 grams in excess, and then sufficient 25% ammonium chlorid solution to dissolve the precipitated copper. Dilute somewhat and titrate as directed under 3 (C) . A correction must be applied for the amount of iodin solu- tion necessary to produce a blue color with starch in the presence of copper (using an equivalent weight of copper sulphate) . The corrected number of cc . of the stand- ard iodin solution used represents directly the per cent of arsenious oxid (AsiOi) in the sample. Method II. 8 CM. Smith Method,^ Modified— Tentative. Proceed as directed in 7, using dilute sulphuric acid (1 to 4) instead of dilute hydrochloric. The solution in this case may be heated to boiling. SODIUM ACETATE-SOLUBLE ARSENIOUS OXID.<— TENTATIVE. 9 REAGENTS. (a) Sodium acetate solution .—Vrepare a solution containing 12.5 grams of the crystallized salt (CHaCOONaSHzO) in each 25 cc. The other reagents are described under 3. 10 DETERMINATION. Place 1 gram of the sample in a 100 cc. flask and boil for 5 minutes with 25 cc. of the sodium acetate. Dilute to the mark, shake, and pass through a dry filter paper. Titrate an aliquot of this filtrate as directed under 3 (C). Calculate the amount of arsenious oxid (AS2O3) present and express the result as per cent of sodium acetate-soluble arsenious oxid. WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE. 11 REAGENTS. Described under 3. 12 DETERMINATION. To 1 gram of the sample in a liter Florence flask add 1 liter of recently boiled water which has been cooled to exactly 32°C. Stopper the flask and place in a water bath kept at 32°C. by means of a thermostat. Digest for 24 hours, shaking hourly for 8 hours during this period. Filter through a dry filter and titrate 250 cc. of the filtrate as directed under 3 (C) . Correct for the amount of the standard iodin neces- sary to produce the same color, using the same reagents and volume. Calculate the amount of arsenious oxid (AS2O3) present and express the result as per cent of water-soluble arsenious oxid. TOTAL COPPER OXID. 13 Electrolytic Method.— Official. Treat 2 grams of the sample in a beaker with 100 cc. of water and about 2 grams of sodium hydroxid and boil thoroughly until all the copper is precipitated as cu- prous oxid. Filter, wash well with hot water, dissolve the precipitate in hot dilute nitric acid, cool, transfer to a 250 cc. graduated flask and dilute to the mark. (1) Use 50-100 cc. of this solution for the electrolytic determination of copper as directed under VIII, 33 and calculate to per cent cupric oxid; or, (2) Electrolyze the aliquot in a weighed 150 cc. platinum dish, using a rotating spiral anode and a current of about 66 METHODS OF ANALYSIS [Chap. 3 amperes. After all the copper is deposited (requiring about 30 minutes), wash the deposit with water bj^ siphoning, then rinse with alcohol, dry for a few min- utes in an oven, weigh and calcula.e to per cent cupric oxid. 14 Thiosulphate Method.^— Official. Determine copper in another aliquot of the nitric acid solution of copper oxid, under 13, by titrating with N/20 thiosulphate solution, as directed under VIII, 29, and calculate to per cent cupric oxiJ. LONDON PURPLE. 15 MOISTURE.-TENTATIVE. Determined as directed under 2. TOTAL ARSENIOUS OXID.«— OFFICIAL. 16 REAGENTS. Described under 3. 17 DETERMINATION. Dissolve 2 grams of the sample in a mixture of about 80 cc. of water and 20 cc. of concentrated hydrochloric acid at a temperature of 60°-70°C.; filter and wash until the combined filtrate and washings measure 250 cc. Treat 100 cc. of this solu- tion with sodium bicarbonate in excess, transfer to a 500 cc. volumetric flask and make up to the mark, adding a few drops of ether to destroy the bubbles. Mix thoroughly and pass through a dry filter. Titrate 250 cc. of the filtrate as directed under 3 (C) and calculate the per cent of arsenious oxid. TOTAL ARSENIC OXID.'— OFFICIAL. 18 REAGENTS. The reagents and solutions used are described under 3. 19 DETERMINATION. Boil, on a hot plate or over a low flame, 2 grams of the sample with 5 cc. of con- centrated nitric acid and 20 cc. of concentrated sulphuric acid in a Kjeldahl diges- tion flask or a covered casserole. After 10-15 minutes add fuming nitric acid or powdered sodium nitrate, in small quantities at a time, until all organic matter is destroyed and the solution is practically colorless. Cool, add about 50 cc. of water ito decompose any nitro-sulphuric acid formed) and heat again until all nitric acid fumes are expelled. Cool, transfer to a 250 cc. volumetric flask, make up to the mark with water, mix thoroughly, and filter through a dry filter. Transfer 50 cc. of this filtrate to a 400 cc. Erlenmeyer flask, dilute with water to 100 cc, add 1 gram of potassium iodid,' heat to boiling and evaporate to about 40 cc. not less). Cool, dilute to 150-200 cc, and remove the excess of iodin with N/20 sodium thiosulphate. In case the solution is slightly colored from organic matter or from any cause other than free iodin, add the thiosulphate until it is nearly colorless, then a few drops of the starch indicator, and continue adding the thio- sulphate slowly until the l)luo color just disappears. Continue at once as directed under 3 C) beginning with "neutralize with sodium bicarbonate." Subtract from this reading the number of cc. of the standard iodin solution corresponding to the arsenious oxid obtained in 1 7. Calculate the per cent of arsenic oxid in the sample. VII] INSECTICIDES AND FUNGICIDES 67 20 WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE. Proceed as directed under 12, slightly acidifying the aliquot employed with hydrochloric acid before adding the excess of sodium bicarbonate. WATER-SOLUBLE ARSENIC OXID.-TENTATIVE. 21 REAGENTS. The solutions and reagents used are described under 3. 22 DETERMINATION. Transfer an aliquot, 250 cc, of the water extract, from 20, to a casserole, add 5 cc. of concentrated sulphuric acid, evaporate to a small volume and heat on a hot plate till white fumes of sulphuric acid appear. Cover the casserole and add 1-2 cc. of fuming nitric acid and again heat till the appearance of white fumes. Cool, add a little water and, in order to expel the last traces of nitric acid, once more evaporate till white fumes appear. Cool, dilute to about 100 cc. with water, add 1 gram of potassium iodid^ and sufficient sulphuric acid to make the total amount present about 5 cc. Boil until the vo'ume is reduced to about 40 cc. Cool, dilute to about 200 cc, remove the excess iodin with N/20 sodium thiosulphate and pro- ceed as directed under 3 (C) beginning with "neutralize with sodium bicarbonate." Correct for the amount of the standard iodin solution necessary to produce the same color, using the same reagents and volume. Subtract from the corrected titra- tion reading the number of cc. of the standard iodin solution corresponding to the arsenious oxid, obtained in 20. Calculate the per cent of arsenic oxid present. LEAD ARSENATE. 23 MOISTURE.-TENTATIVE. (a) Powder. — Dry 2 grams to constant weight at lOS^-llO" C. and report the loss in weight as moisture. (b) Paste. — Proceed as under (a), using 50 grams. Grind the dry sample to a fine powder, mix well, transfer a small portion to a sample bottle and again dry for 1-2 hours at 105°-110°C., and use this anhydrous material for the determination of total lead oxid and total arsenic. TOTAL LEAD OXID. 24 Method I. ^—Official. Heat, on a hot plate, 0.6906 gram of the dry powdered sample with about 25 cc. of dilute nitric acid (1 to 4) in a 600 cc. beaker. If necessarj^ remove any insoluble residue by filtration. Dilute to at least 400 cc, heat nearly to boiling, add am- monium hydroxid to incipient precipitation, then dilute nitric acid ,1 to 10) to re- dissolve the precipitate, adding 1-2 cc. in excess. Pipette into this solution, kept almost boiling, 50 cc. of a hot 10% potassium chromate solution, stirring constantly. Decant while hot through a weighed Gooch, previously heated at 140°-150°C., wash several times by decantation and then on the filter with boiling water until the washings are colorless. Dry the lead chromate at UO'-LoO^C. to constant weight. The weight of lead chromate multiplied by 100 gives the per cent of lead monoxid (PbO) in the dried sample. The lead chromate precipitate maj' contain a small amount of lead arsenate which causes slightly high results. This error rarely amounts to more than 0.1-0.2%. 68 METHODS OF ANALYSIS [Chap. Method 11. ^0— Tentative. (Not applicable in the presence of calcium.) 25 REAGENT. Acidified alcohol.— Mix water 100 parts; 95% alcohol 200 parts; and concentrated sulphuric acid 3 parts by volume. 26 DETERMINATION. Heat, on a hot plate, 0.73G0 gram of the dry powdered sample with about 25 cc. of dilute nitric acid (1 to 4) in a porcelain evaporating dish or casserole. Remove any insoluble residue by filtration. Add 3 cc. of concentrated sulphuric acid and evaporate on the hot plate to the appearance of white fumes. It is important that all nitric acid be expelled. Cool, add 50 cc. of water and about 100 cc. of 95% alco- hol, let stand several hours (preferably over-night) and filter through a weighed Gooch crucible, previously washed with water, the acidified alcohol and 95% alco- hol, and dried at 200°C. Wash the precipitate of lead sulphate in the crucible about 10 times with the acidified alcohol and then with 95% alcohol until free from sul- phuric acid. Dry at 200°C. to constant weight, keeping the crucible covered to pre- vent loss by spattering. The weight of the lead sulphate multiplied by 100 gives the per cent of lead monoxid (PbO) in the dried sample. TOTAL ARSENIC. 27 Method I. ^—Official. Proceed as directed under 5, using an amount of the sample equal to the arsenic oxid equivalent of 500 cc . of the standard iodin solution and titrating a 200 cc . aliquot of the distillate. The number of cc. used of the standard iodin solution represents directly the total per cent of arsenic in the sample expressed as arsenic oxid (AS2O6) . Method 11.^^— Official. (Not applicable in the presence of antimony.) 28 REAGENTS. The reagents and solutions used are described under 3. 29 DETERMINATION. Dissolve an amount of the powdered sample equal to the arsenic oxid equivalent of 400 cc. of the standard iodin solution, in dilute nitric acid in a porcelain casserole or evaporating dish. Add 5 cc. of concentrated sulphuric acid and heat on the hot plate to copious evolution of white fumes. Wash into a 200 cc. graduated flask with water, cool, make up to the mark and filter through a dry filter. Transfer 100 cc. of the filtrate to an Erlenmeyer flask and proceed as directed under 22, beginning with ''add 1 gram of potassium iodid," to "Subtract from the corrected titration reading." The number of cc. of the standard iodin solution used, divided by 2, represents directly the per cent of total arsenic in the sample expressed as arsenic oxid (As205)- WATER-SOLUBLE ARSENIC OXID. -TENTATIVE. 30 REAGENTS. The reagents and solutions used are described under 3. Vn] INSECTICIDES AND FUNGICIDES 69 31 DETERMINATION. Treat 2 grams of the original sample, if in the form of a powder, or 4 grams, if a paste, as directed under 12 through "Filter through a dry filter." Place 250-500 cc. of the clear filtrate in an Erlenmeyer flask, add 3 cc. of con- centrated sulphuric acid and evaporate on a hot plate. When the volume is re- duced to about 100 cc, proceed as directed under 22 to "Subtract from the cor- rected titration reading." Calculate and report as per cent of water-soluble arsenic oxid (AsiOs). CALCIUM ARSENATE. 32 TOTAL ARSENIC— OFFICIAL. Proceed as directed under 5, using an amount of the powdered sample equal to the arsenic oxid equivalent of 250 cc. of the standard iodin solution. The number of cc. of the standard iodin solution used represents directly the total per cent of arsenic in the sample expressed as arsenic oxid (AS2O8) . ZINC ARSENITE. 33 TOTAL ARSENIC.1-0FFICLA.L. Proceed as directed under 5, using an amount of the powdered sample equal to the arsenious oxid equivalent of 500 cc. of the standard iodin solution and titrating a 200 cc. aliquot of the distillate. The number of cc. of the standard iodin solution used represents directly the per cent of total arsenic in the sample expressed as ar- senious oxid (AS2O3). 34 TOTAL ARSENIOUS OXID.— TENTATIVE. Proceed as directed under 7 or 8. COPPER CARBONATE. 35 COPPER OXID.— OFFICIAL. Dissolve a weighed quantity of the substance in dilute nitric acid and deter- mine copper as directed under 13 or 14. BORDEAUX MIXTURE. 36 MOISTURE.-OFFICIAL. (a) Powder. — Dry 2 grams to constant weight at 105°-110°C. and express the loss in weight as moisture. (b) Paste. — Heat about 100 grams in an oven at 90-100°C. until dry enough to powder readily, and note the loss in weight. Powder this partially dried sample, and determine the remaining moisture in 2 grams as under la). Determine car- bon dioxid, as directed under 38, both in the original paste and in this partially dried sample. Calculate the total moisture by the following formula: M = a + (100-a) (b + c) - d in which M = per cent total moisture in original paste; a = per cent loss in weight of original paste during first drying; b = per cent loss in weight of partially dried paste during second drying; c = per cent carbon dioxid remaining in partially dried paste after first drying; d = per cent total carbon dioxid in original paste. 70 METHODS OF ANALYSIS [Chap. CARBON DIOXID."— OFFICIAL. 37 APPARATUS. This consists of a 200 cc. Erlenmeyer flask closed with a 2-holed stopper; one of these holes is fitted with a dropping funnel the stem of which extends almost to the bottom of the flask; the outlet of a condenser, which is inclined upward at an angle of 30° from the horizontal, passes downward through the other hole. The upper end of the condenser is connected with a calcium chlorid tube which in turn ia connected with a double U-tube filled in the middle with pumice fragments, pre- viously saturated with copper sulphate solution and subsequently dehydrated, and with calcium chlorid at either end. Then follow 2 weighed U-tubes for absorb- ing the carbon dioxid, the first filled with porous soda-lime, and the second, one third with soda-lime and two thirds with calcium chlorid, the latter reagent being placed at the exit end of the train. A Geissler bulb, partly filled with sulphuric acid, is attached to the last U-tube to show the rate of gas flow. An aspirator is connected with the Geissler bulb to draw air through the apparatus. An absorp- tion tower filled with soda-lime is connected with the mouth of the dropping funnel to remove carbon dioxid from the air entering the apparatus. 38 DETERMINATION. Weigh 2 grams of the powder or 10 grams of the paste into the Erlenmeyer flask, add about 20 cc. of water, attach the flask to the apparatus omitting the 2 weighed U-tubes, and draw carbon dioxid-free air through the apparatus until the original air is displaced. Then attach the weighed U-tubes in the position as described in 37, close the stop-cock of the dropping funnel, fill half full with dilute hydrochloric acid (1 to 1), reconnect with the soda-lime tower, and allow the acid to flow into the Erlenmeyer flask, slowly if there is much carbon dioxid, rapidly if there is little. When effervescence diminishes, place a low Bunsen flame under the flask and start a flow of water through the condenser, a slow current of air being allowed to flow through the apparatus at the same time. Maintain a steady but quiet ebulli- tion, and a slow air current through the apparatus. Boil for a few minutes after the water has begun to condense in the condenser, then remove the flame and con- tinue the aspiration of air at the rate of about 2 bubbles per second until the apparatus is cool. Disconnect the tared absorption tubes, cool in the balance case and weigh. The increase in weight is due to carbon dioxid. COPPER. 39 Electrolytic Method.— Official. Dissolve 2 grams of the dry powdered sample in 20 cc. of water and 5 cc. of con- centrated nitric acid, dilute to 100 cc, wash into a weighed 150 cc. platinum dish, and electrolyze, using a rotating spiral anode and a current of about 3 amperes. After all the copper is deposited (.requiring about 30 minutes), wash the deposit with water by siphoning, then rinse with alcohol, dry for a few minutes in an oven, and weigh. Calculate the per cent of copper in the sample. 40 Thiosulphate Method.— Official. Dissolve 2 grams of the dry powdered sample in about 50 cc. of 10% nitric acid, add ammonium hydroxid solution in excess and heat; then, without removing the precipitate which is formed, boil off the excess of ammonia, add 5-10 cc. of acetic acid, cool, add 10 cc. of 30% potassium iodid solution, and titrate as directed under VIIL 29. Vn] INSECTICIDES AND FUNGICIDES 71 BORDEAUX MIXTURE WITH PARIS GREEN. 41 MOISTURE.-OFFICIAL. Proceed as directed under 36. 42 CARBON DIOXID.-OFnCIAL. Proceed as directed under 38. COPPER. 43 Method I— Tentative. Dissolve 2 grams of the dry powdered sample in a few cc. of strong nitric acid, add 25 cc. of a 3% solution of hydrogen peroxid and warm for 5-10 minutes. Make slightly alkaline with ammonium hydroxid and then slightly acid again with dilute nitric acid. Transfer to a weighed 150 cc. platinum dish, add 15-20 cc. of hydrogen peroxid, dilute to 100 cc. and electrolyze, using a rotating spiral anode and a cur- rent not exceeding 2 amperes. After the electrolysis has proceeded for about 20 minutes, add to the electrolyte 0.5 gram of ferric sulphate dissolved in a few cc. of water together with a drop or two of nitric acid. After all the copper is deposited, wash the deposit with water by siphoning, then rinse with alcohol, dry for a few minutes in an oven, weigh and calculate the per cent of copper. (Do not pass the current for more than 5-10 minutes after all the copper has been deposited without adding more ferric sulphate solution.) 44 Method II. — Tentative. Treat 1 gram of the dry powdered sample with 20 cc. of water and 5-6 cc. of con- centrated nitric acid, heat to boiling, cool, and add a slight excess of concentrated ammonium hydroxid. Wash the solution and precipitate into a weighed platinum dish of about 150 cc. capacity, and electrolyze, using a rotating anode and a cur- rent of about 4 amperes and 3-4 volts for about 90 minutes (.or until all the copper is deposited) . Wash the deposit by siphoning until the deposit is clean, being care- ful not to use too much wash water. Dissolve the copper in 5 cc. of concentrated nitric acid, dilute to 100 cc. and electrolyze as before, except that all the copper will be deposited in 30 minutes. Wash the deposit with water by siphoning, then rinse with alcohol, dry for a minute or so in an oven, weigh and calculate the per cent of copper. 45 TOTAL ARSENIC-OFFICIAL. Proceed as directed under 5, using an amount of the dry powdered sample equal to the arsenious oxid equivalent of 500 cc. of the standard iodin solution. The num- ber of cc. of the standard iodin solution used, divided by 2, represents directly the per cent of total arsenic in the sample expressed as arsenious oxid (AsjOs). TOTAL ARSENIOUS OXID. 46 Method I.— Tentative. Proceed as directed under 7, using an amount of the dry, powdered sample equal to the arsenious oxid equivalent of 200 cc. of the standard iodin solution. Before titrating, all the copper must be in solution. The corrected number of cc. of the standard iodin solution used, divided by 2, represents directly the per cent of total arsenious oxid (AS2O3) in the sample. 72 METHODS OF ANALYSIS [Chap. 47 Method II.— Tentative. Proceed as directed under 8. 48 WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE. Proceed as directed under 20, using 2 grams of the sample. BORDEAUX MIXTURE WITH LEAD ARSENATE. 49 MOISTURE.-OFFICLAL. Proceed as directed under 36. 50 CARBON DIOXID.— OFFICIAL. Proceed as directed under 38. 51 COPPER.-TENTATIVE. Proceed as directed under 44. 52 LEAD OXID.3— TENTATIVE. Dissolve the lead peroxid (which will contain a little arsenic) from the anodes used in the copper electrolysis, under 51 , by means of dilute nitric acid and a little hydrogen peroxid, and add to this solution the washings from both electrolyses of copper. Add ammonium chlorid to dissolve any lead sulphate which may have precipitated out and make the solution up to 1 liter. Concentrate a 500 cc. aliquot of this solution to about 300 cc. (all hydrogen peroxid must be expelled from the solution), transfer to a 400 cc. beaker and precipitate the lead as lead chromate as directed under 24. 53 TOTAL ARSENIC.i-OFFICIAL. Proceed as directed under 5, using an amount of the dry, powdered sample equal to the arsenic oxid equivalent of 500 cc. of the standard iodin solution. The num- ber of cc. of the standard iodin solution used, divided by 2, represents directly the per cent of total arsenic in the sample expressed as arsenic oxid (AszOs). 54 WATER-SOLUBLE ARSENIC OXID.-TENTATIVE. Proceed as directed under 31 . SODIUM AND POTASSIUM CYANIDS. 55 CYANOGEN.is— OFFICLAL. Weigh about 10 grams of the sample in a weighing bottle, dissolve in water, and make up to volume in a liter graduated flask. To a 50 cc. aliquot add N/20 silver nitrate, drop by drop, stirring constantly, until 1 drop produces a permanent tur- bidity. In calculating the results, 1 equivalent of silver is equal to 2 equivalents of cyanogen, according to the following equation: 2NaCN + AgNOa = NaCNAgCN + NaNOj Reserve the titrated solution for the determination of chlorin under 56. Vn] INSECTICIDES AND FUNGICIDES 73 5g CHLORIN.K— OFFICIAL. After completion of the titration for cyanogen, as directed under 55, add a few cc. of 10% potassium chromate solution as indicator and titrate with N/20 silver nitrate until the appearance of the red-brown color of silver chromate. The first titration with silver nitrate represents the cyanogen present according to the equation above. The second titration represents the cyanogen and chlorin according to the following equation : NaCNAgCN + NaCl + 2AgN03 = 2NaN03 + 2AgCN + AgCl. Therefore the second minus the first reading represents the chlorin present in terms of silver nitrate. SOAP. 57 Modified Method of Benedickt and Lewkowitsch.^^ — Tentative. Weigh about 5 grams of the sample in a tared, 100 cc. beaker, in which is pre- viously placed a 5 inch layer of recently ignited, dry sand, and a small glass rod; if the soap is hard, cut off the soap in very thin strips. Add 25 cc. of alcohol, or more if necessary, and dissolve on the water bath, stirring constantly. Evapo- rate the alcohol, heat in an oven at 110°C. until the soap is nearly dry, and weigh, then dry again for 30 minutes and weigh. Continue this alternate drying and weighing until the weight changes only a few milligrams during the course of 30 minutes' drying. 58 POTASSIUM AND SODIUM."— TENTATIVE. Dissolve about 5 grams of the soap in water; decompose with hydrochloric acid, filter off the water and wash the fat with cold water. Determine both potassium and sodium in the filtrate as directed under II, 21 . SODA LYE. 59 CARBONATE AND HYDROXID.i'— OFFICIAL. Weigh about 10 grams of the sample from the weighing bottle, dissolve in car- bon dioxid-free water and make up to a definite volume. Titrate an aliquot of this solution with N/2 hydrochloric acid, using methyl orange as an indicator, and note the total alkalinity thus found. Transfer an equal aliquot to a graduated flask and add enough barium chlorid solution to precipitate all the carbonate, avoiding any unnecessary excess. Dilute to the mark with carbon dio.xid-free water, stopper, shake, and set aside. When the liquid becomes clear, pipette off one half and ti- trate with N/2 hydrochloric acid, using phenolphthalein as an indicator. The number of cc. of N/2 acid, required for this titration, multiplied by 2 gives the num- ber of cc. of N/2 acid required to neutralize the sodium hydroxid present in the original aliquot. The difference between this figure and the number of cc. of N/2 hydrochloric acid required for the total akalinitj' represents the number of cc. of N/2 acid required to neutralize the sodium carbonate present in the aliquot. Cal- culate the percentages of sodium carbonate and hydroxid present in the sample. TOBACCO AND TOBACCO EXTRACT. NICOTIN. Kissling Method. — Official. 60 REAGENTS. (a) Alcoholic sodium hydroxid solution. — Dissolve 6 grams of sodium hydroxid in 40 cc. of water and 60 cc. of 90% alcohol. 74 METHODS OF ANALYSIS [Chap. (b) 04% sodium hydroxid solution. (C) N /W sulphuric acid. — One cc. is equivalent to 16.22 mg. of nicotin. (d) Phenacetolin solution. — Prepare a 0.5% alcoholic solution. (e) Cochineal solution. — Prepare as directed under I, 16 (k). 61 DETERMINATION. Weigh 5-6 grams of tobacco extract, or 20 grams of finely powdered tobacco which has been previously dried at 60°C. if necessary, into a small beaker. Add 10 cc. of the alcoholic sodium hydroxid and follow, in the case of tobacco extract, with enough pure powdered calcium carbonate to form a moist but not lumpy mass. Mix thoroughly, transfer to a Soxhlet extractor and exhaust for about 5 hours with ether. Evaporate the ether at a low temperature, and take up the residue with 50 cc. of the 0.4% sodium hydroxid solution. Transfer this residue by means of water to a 500 cc. Kjeldahl flask, and distil with steam, passing the distillate through a condenser cooled by a rapidly flowing current of water. Use a 3-bend outflow tube, and, to prevent bumping and frothing, add a few pieces of pumice, and a small piece of paraffin. Distil till all the nicotin has passed over, the distillate usually varying from 400-500 cc. When completed, only about 15 cc. of the liquid should remain in the flask. Titrate the distillate with N/10 sulphuric acid, using the phenacetolin or cochineal solution as indicator. Silicotungstic Acid Method.^^ — Official. 62 REAGENTS. (a) Silicotungstic acid solution. — Prepare a 12% solution of the silicotungstic acid having the following formula: 4H20.Si02.12W03.22H20. (b) Sodium or potassium hydroxid solution [1 to 2). (C) Dilute hydrochloric acid {1 to 4) • 63 DETERMINATION. Weigh such an amount of the preparation as will contain preferably between 0.1 and 1.0 gram of nicotin (if the sample contains very little nicotin, about 0.1%, do not increase the amount to the point where it interferes with the distillation) ; wash with water into a500cc. round-bottomed distillation flask; add a little paraffin to pre- vent frothing, a few small pieces of pumice and a slight excess of the sodium or potassium hydroxid, using phenolphthalein as an indicator. Distil rapidly in a current of steam through a well-cooled condenser, connected by means of an adapter with a suitable flask containing 10 cc. of the dilute hydrochloric acid. When distil- lation is well underway, heat the distillation flask to reduce the volume of the liquid as far as practicable without bumping or undue separation of insoluble matter. Dis- til until a few cc. of the distillate show no cloud or opalescence when treated with a drop of the silicotungstic acid and a drop of the dilute hydrochloric acid. Confirm the alkalinity of the residue in the distillation flask with phenolphthalein solution. Make up the distillate, which may amount to 1000-1500 cc, to a convenient volume (the solution may be concentrated on the steam bath without loss of nicotin), mix well and pass through a large dry filter if not clear. Test a portion with methyl orange to assure its acidity. Pipette an aliquot, containing about 0.1 gram of nicotin, into a beaker lif the samples contain very small amounts of nicotin, an aliquot contain- ing as little as 0.01 gram of nicotin may be used), add to each 100 cc. of liquid 3 cc. of the dilute hydrochloric acid, or more if the necessity is indicated by the test with methyl orange, and add 1 cc. of the silicotungstic acid for each 0.01 gram of nico- VII] INSECTICIDES AND FUNGICIDES 75 tin supposed to be present. Stir thoroughly and let stand overnight. Before filter- ing, stir the precipitate to see that it settles quickly and is in crystalline form; then filter on an ashless filter paper, and wash with cold dilute hydrochloric acid (1 to 1000). Transfer the paper and precipitate to a weighed platinum crucible, dry carefully, and ignite until all carbon is destroyed. Finally heat over a Teclu or Meker burner for not more than 10 minutes. The weight of the residue multiplied by 0.114 gives the weight of nicotin present in the aliquot. FORMALDEHYDE SOLUTIONS. FORMALDEHYDE. Hydrogen Peroxid Method.^^ — Official. 64 REAGENTS. (a) N/1 sulphuric acid. (b) N/1 sodium hydroxid. — One cc. is equivalent to 30.02 mg. of formaldehyde. (C) Hydrogen peroxid. — An approximately 3% solution. If the hydrogen per- oxid solution is acid, neutralize with (b), using litmus solution as indicator. (d) Litmus solution. — A solution of purified litmus. 65 DETERMINATION. Measure 50 cc. of N/1 sodium hydroxid into a 500 cc. Erlenmeyer flask and add 50 cc. of the hydrogen peroxid. Then add 3 grams of the formaldehyde solution un- der examination, allowing the point of the pipette to reach nearly to the liquid in the flask. Place a funnel in the neck of the flask and heat on the steam bath for 5 min- utes, shaking occasionally. Remove from the steam bath, wash the funnel with water, cool the flask to about room temperature, and titrate with N/1 acid, using the litmus solution as indicator. It is necessary to cool the flask before titration with the acid to get a sharp end point with the litmus. Calculate the per cent of formaldehyde. Cyanid Method.^"— Official. 66 REAGENTS. (a) N^/IO silver nitrate. (b) N/10 ammonium sulphocyanate. (C) Potassium cyanid solution. — Dissolve 3.1 grams of potassium cyanid in 500 cc. of water. (d) 50% nitric acid. 67 DETERMINATION. Treat 15 cc. of the N/10 silver nitrate with 6 drops of the 50% nitric acid in a 50 cc. volumetric flask; add 10 cc. of the potassium cj-^anid solution, dilute to the mark, shake well, filter through a dry filter and titrate 25 cc. of the filtrate with N/10 ammonium sulphocyanate as directed under III, 15. Acidify another 15 cc. portion of the N/10 silver nitrate with 6 drops of the 50% nitric acid and treat with 10 cc. of the potassium cyanid solution to which has been added a measured quan- tity (the weight of which must be calculated from the specific gravity) of the for- maldehyde solution containing not over 2.5 grams of a 1% solution or the equiva- lent. Make up to 50 cc, filter and titrate a 25 cc. aliquot with the N/10 ammonium sulphocyanate for the excess of silver as before. The difference between the num- ber of cc. of N/10 ammonium sulphocyanate used in these 2 titrations, multiplied 76 METHODS OF ANALYSIS [Chap. by 2, gives the number of cc. of N/10 ammonium sulphocyanate corresponding to the potassium cyanic! used by the formaldehyde. Calculate the per cent of for- maldehyde present U cc. of N/10 ammonium sulphocyanate is equivalent to 3 mg. of formaldehyde (HCHO)). LIME-SULPHUR SOLUTIONS.^i TOTAL SULPHTJR.-OFFICIAL. 68 PREPARATION OF SOLUTION. Weigh 10 grams of the solution and dilute to the mark in a 250 cc. graduated flask with recently boiled and cooled water. 69 DETERMINATION. Transfer a 10 cc. aliquot to a 400 cc. beaker, add about 3 grams of sodium peroxid, cover immediately with a watch glass and warm on the steam bath, with frequent shaking, until all the sulphur is oxidized to sulphate, adding more sodium peroxid if necessary. Dilute, acidify with hydrochloric acid, evaporate to dryness, treat with water acidified with hydrochloric acid, boil, and filter to remove silica, if pres- ent. Dilute the filtrate to 300 cc, add 50 cc. of concentrated hydrochloric acid," heat to boiling, and precipitate with 10% barium chlorid solution slowly and stir- ring constantly. (The rate is best regulated by attaching a suitable capillary tip to the burette containing the barium chlorid solution.) Evaporate to dryness on the steam bath, take up with hot water, filter through a quantitative filter paper, wash until free from chlorin, ignite and heat to constant weight over a Bunsen burner. Calculate the sulphur from the weight of barium sulphate. Previous to use test the reagents for sulphur and, if present, make corrections accordingly. SULPHID SULPHTJR.-OFFICIAL. 70 REAGENT. Ammoniacal zinc solution. — Dissolve 50 grams of pure zinc chlorid in water, add ammonium hydroxid in sufficient quantity to redissolve the precipitate first formed, then add 50 grams of ammonium chlorid^' and dilute to 1 liter. 71 DETERMINATION. Dilute 10 cc. of the solution, prepared as directed under 68, to about 100 cc. and add the ammoniacal zinc solution until the sulphid is all precipitated, indicated by the addition of a drop of the clear solution to a few drops of nickel sulphate solution. Filter immediately, wash the precipitate thoroughly with cold water and transfer it and the filter paper to a beaker. Cover with water, disintegrate with a glass rod and add about 3 grams of sodium peroxid, keeping the beaker well covered with a watch glass. Warm on the steam bath with frequent shaking until all the sulphur is oxidized to sulphate, adding more sodium peroxid if necessary. Make slightly acid with hydrochloric acid, filter to remove shreds of filter paper, wash thoroughly with hot water, and determine the -sulphur in the filtrate exactly as under 69. 72 THIOSULPHATE SULPHTJR.-OFFICIAL. Dilute 50 cc. of the solution, prepared as under 68, to about 100 cc. in a 200 cc. graduated flask. Add a slight excess of the ammoniacal zinc chlorid and dilute to the mark. Shake thoroughly and filter through a dry filter. To 100 cc. of the fil- trate add a few drops of methyl orange and exactly neutralize with N/10 hydrochloric Vn] INSECTICIDES AND FUNGICIDES 77 acid. Titrate this neutral solution with approximately N/20 iodin, 3 ^C), using a few drops of starch solution as indicator. From the number of cc. of iodin solu- tion used, calculate the thiosulphate sulphur present. 73 SULPHATE SULPHUR.— OFFICIAL. To the solution from the determination in 72, add 2 or 3 drops of hydrochloric acid, precipitate in the cold with 10% barium chlorid solution, allow to stand over- night, filter, calculate the sulphur from the weight of barium sulphate and report as sulphate sulphur. 74 TOTAL LIME.— OFFICIAL. To 25 cc. of the solution, prepared as under 68, add 10 cc. of concentrated hydro- chloric acid, evaporate to dryness on the steam bath, treat with water and a little hydrochloric acid, warm until all the calcium chlorid is dissolved, and filter from sul- phur and any silica that may be present. O.xidize the filtrate by boiling with a little concentrated nitric acid, make ammoniacal, filter from iron and aluminium if present, heat to boiling and precipitate the calcium with ammonium oxalate so- lution. Filter, wash and ignite over a blast lamp to constant weight; weigh the residue as calcium o.xid. BIBLIOGRAPHY. 1 J. Ind. Eng. Chem., 1916, 8: 327. ' Ibid., 1909, 1: 208. » J. Assoc. Official Agr. Chemists, 1915, 1: 436, 446. « J. Am. Chem. Soc, 1901, 23: 115. » Ibid., 1902, 24: 1082. « Ibid., 1900, 22: 802. ' U. S. Bur. Chem. Bull. 122, p. 106. » Am. J. Sci., 1890. 3rd ser., 40: 66. ' U. S. Bur. Chem. Bull. 137, p. 40. '"Ibid., 105, p. 166. " Ibid., p. 167. ^^ Fresenius. Quantitative Chemical Analysis. Revised and amplified transla- tion of the 6th German ed., 2 : 1180; U. S. Geol. Surv, Bull. 422, p. 179. '^ Sutton. Volumetric Analysis. 10th ed., 1911, p. 207. i< Ibid., 9th ed., rev., p. 201. 1^ Lewkowitsch. Chemical Technology and Analysis of Oils, Fats and Waxes. 5th ed., 1915, 3: -348. '«Ibid., 346. '^ Sutton. Volumetric Analysis. 10th ed., 1911, p. 61. >« U. S. Bur. Animal Industry, Bull. 133. I' Ber., 1898, 31: 2979; J. Am. Chem. Soc, 1905, 27: 1183; U. S. Bur. Chem. Bull. 99, p. 30; 132, p. 49; 137, p. 47. " Z. anal. Chem., 1897, 36: 18; U. S. Bur. Chem. Bull. 132, p. 49. " J. Assoc. Official Agr. Chemists, 1915, 1 : 76. " J. Am. Chem. Soc, 1911, 33: 844. » J. Soc. Chem. Ind., 1912, 31: 369. VIII. FOODS AND FEEDING STUFFS. 1 PREPARATION OF SAMPLE.— OFFICIAL. Grind the sample so that it will pass through a sieve having circular openings it inch (1 mm.) in diameter. If the sample can not be ground, reduce it to as fine a state as possible. 2 Direct Drying. — Official. Dry a quantity of the substance, representing about 2 grams of dry material, in a current of dry hydrogen or in vacuo at the temperature of boiling water to constant weight (approximately 5 hours). If the substance be held in a glass vessel, the latter should not be in contact with the boiling water. 3 Drying in Vacuo without Heat. — Tentative. Mix the sample thoroughly and weigh by difference 2-5 gram portions from a stoppered weighing bottle into tared, covered crucibles. Where subsequent fat determinations are to be made, fat extraction cones may be used. Substances that dry down to horn-like material should be mixed with fat-free cotton or other suit- able material (previously tared with the container). Place 200 cc. of fresh concen- trated sulphuric acid in a strong, tight 6 inch vacuum desiccator. Put triplicate samples in separate desiccators, and exhaust by means of a vacuum pump. If a pump is not available, place 10 cc. of ether in a small beaker in the desiccator, and exhaust with a water filter pump. Between the pump and the desiccator interpose an empty bottle, next to the desiccator, and a bottle of water. Draw the air from the desiccator through the water and turn the desiccator stop-cock at just the instant when the water begins to rise in the tube leading from the empty bottle. Gently rotate the desiccator 4 or 5 times during the first 12 hours to mix the sul- phuric acid with the water which has collected as an upper layer. At the end of 24 hours open the desiccator, forcing the incoming air to bubble through concentrated sulphuric acid, and make the first weighing. After weighing place in a desiccator containing fresh concentrated sulphuric acid and exhaust as before. Rotate the desiccator several times during the interval and weigh again after a suitable period of drying. Repeat this process of drying in vacuo over sulphuric acid until the weight is constant. 4 ASH.— OFFICIAL. Char a quantity of the substance, representing about 2 grams of the dry material, and burn until free from carbon at a low heat, not to exceed dull redness. If a carbon-free ash can not be obtained in this manner, exhaust the charred mass with hot water, collect the insoluble residue on a filter, burn till the ash is white or nearly so, and then add the filtrate to the ash and evaporate to dryness. Heat to low redness till the ash is white or grayish white and weigh. 79 80 METHODS OF ANALYSIS [Chap. 5 CRUDE PROTEIN.-OFFICIAL. Determine nitrogen as directed under I, 18,21, or 23, and multiply the result by 6.25. ALBUMINOID NITROGEN.— OFFICIAL. 6 REAGENT. Stutzer's reagent.— Frepare cupric hydroxid as follows: Dissolve 100 grams of pure copper sulphate in 5 liters of water, add 2.5 cc. of glycerol, and then dilute sodium hydroxid solution until the liquid is just alkaline; filter, rub the precipitate up with water containing 5 cc. of glycerol per liter, and wash by decantation or filtration until the washings are no longer alkaline. Rub the precipitate up again in a mortar with water containing 10% of glycerol, thus preparing a uniform gelatinous mass that can be measured with a pipette. Determine the quantity of copper hydroxid per cc. of this mixture. 7 DETERMINATION. Place 0.7 gram of the substance in a beaker, add 100 cc. of water, and heat to boiling ; or, in case of substances rich in starch, heat on the water bath for 10 minutes ; add a quantity of the Stutzer's reagent containing about 0.5 gram of the hydroxid; stir thoroughly, filter when cold, wash with cold water, and, without removing the precipitate from the filter, determine the nitrogen according to I, 18, 21 or 23, adding sufficient potassium sulphid solution to completely precipitate all of the copper and mercury. The filter paper used must be practically free from nitrogen. If the material (such as seeds, seed residue, or oil cake) is rich in alkaline phos- phates, add, to decompose the alkaline phosphates, 1-2 cc. of a concentrated potash or soda alum solution, free from ammonia, then the copper hydroxid, and mix well by stirring. If this is not done, copper phosphate and free alkali may be formed, and the protein-copper precipitate partially dissolved in the alkaline liquid. 8 AMIDO NITROGEN.-OFFICDa. Subtract the amount of albuminoid nitrogen from the amount of total nitrogen to obtain the amido nitrogen. CRUDE FAT OR ETHER EXTRACT. Direct Method. — Official. Anhydrous ether. — Wash any of the commercial brands of ether with 2 or 3 suc- cessive portions of water, add solid sodium or potassium hydroxid, and let stand until most of the water has been abstracted from the ether. Decant into a dry bottle, add small pieces of carefully cleaned metallic sodium, and let stand until there is no further evolution of hydrogen gas. Keep the ether, thus dehydrated, over metallic sodium in lightly stoppered bottles. 10 DETERMINATION. Large quantities of soluble carbohydrates may interfere with the complete ex- traction of the fat. In such cases extract with water before proceeding with the determination. Extract about 2 grams of material, dried as under 2 or 3, with the anhydrous ether for 16 hours. Dry the extract at the temperature of boiling water for 30 minutes, cool in a desiccator, and weigh; continue, at 30 minutes intervals, this alternate drying and weighing to constant weight. For most feeds a period of 1-1 i hours is required. Vni] FOODS AND FEEDING STUFFS 81 11 Indirect Method. — Official. Determine the moisture, as directed in 2 or 3, then extract the dried substance for 16 hours as directed under 10, dry again and regard the loss of weight as ether extract. Sucrose. OPTICAL METHODS. 1 2 GENERAL DIRECTIONS FOR RAW SUGARS— TENTATIVE. (Rules' of the International Commission for Unifying Methods of Sugar Analysis.) "In general all polarizations are to be made at 20°C." "The verification of the saccharimeter must also be made at 20°C. For instru- ments using the Ventzke scale 26 grams of pure dry sucrose, weighed in air with brass weights, dissolved in 100 metric cc. at 20°C. and polarized in a room, the tem- perature of which is also 20°C., must give a saccharimeter reading of exactly 100.00. The temperature of the sugar solution during polarization must be kept constant at 20°C." "For countries where the mean temperature is higher than 20°C., saccharimeters may be adjusted at 30°C. or any other suitable temperature, under the conditions specified above, provided that the sugar solution be made up to volume and polarized at this same temperature." "In effecting the polarization of substances containing sugar employ only half- shade instruments." The saccharimeter used can be either single or double wedge and should be a half-shadow instrument with either double or triple field. "During the observation keep the apparatus in a fixed position and so far removed from the source of light that the polarizing Nicol is not warmed." "As sources of light employ lamps which give a strong illumination such as triple gas burner with metallic cylinder, lens and reflector; gas lamps with Auer (Welsbach) burner; electric lamp; petroleum duplex lamp; sodium light." When- ever there is any irregularity in the sources of light such as that due to the convolu- tions of the filament in the case of electric light or to the meshes of the gauze in the case of the Welsbach light, place a thin ground-glass plate between the source of light and the polariscope so as to render the illumination uniform. "Before and after each set of observations the chemist must satisfy himself of the correct adjustment of his saccharimeter by means of standardized quartz plates. He must also previously satisfy himself of the accuracy of his weights, polarization flasks, observation tubos and cover-glasses. (Scratched cover-glasses must not be used.) Make several readings and take the mean thereof, but no one reading may be neglected." Such plates are standardized to read to the second decimal point and by their use a quick and at the same time accurate test can be made. In using such plates for testing saccharimeters, it is necessary that the instrument, as well as the plate, be at 20°C. before making a reading. Different points of the scale, preferably 20°, 50°, 80°, and 100°, (sugar scale) should be tested against the plates. "In making a polarization use the whole normal weight for 100 cc. or a multiple thereof for any corresponding volume." "As clarifying and decolorizing agents use cither basic acetate of lead, alumina cream, or concentrated solution of alum. Boneblack and decolorizing powders are to be excluded." Whenever reducing sugars are determined in the solution for po- larizing, use only neutral lead acetate for clarification as basic lead acetate causes precipitation of some of the reducing sugars. In addition to these clarifying agents, 82 METHODS OF ANALYSIS [Chap. neutral lead acetate and basic lead nitrate (Herles' solution) have been made official by the Association. "After bringing the solution exactly to the mark at the proper temperature, and after wiping out the neck of the flask with filter paper, pour all of the well-shaken clarified sugar solution on a rapidly acting filter. Reject the first portions of the filtrate, and use the rest, which must be perfectly clear, for polarization." It is advisable to reject the first 20 cc. that run through, then cover the funnel with a watch glass and use the remainder for polarization. In no case should the whole solution or any part be returned to the filter. If cloudy after the 20 cc. have been rejected, begin a new determination. "Whenever white light is used in polarimetric determinations, the same must be filtered through a solution of potassium dichromate of such a concentration that the percentage content of the solution multiplied by the length of the column of the solu- tion in centimeters is equal to nine." This concentration must be doubled in reading carbohydrate materials of high rotation dispersion, such as commercial glucose, etc. 13 PREPARATION AND USE OF CLARIFYING REAGENTS.— TENTATIVE. (a) Basic lead acetate solution. — Boil 430 grams of neutral lead acetate, 130 grams of litharge, and 1 liter of water for 30 minutes. Allow the mixture to cool and settle and dilute the supernatant liquid to a specific gravity of 1.25 with recently boiled water. Solid basic lead acetate may be substituted for the normal salt and litharge in the preparation of the solution. (b) Ahimina cream. — Prepare a cold saturated solution of alum in water. Add ammonium hydroxid with constant stirring until the solution is alkaline to litmus, allow the precipitate to settle and wash by decantation with water until the wash water gives only a slight test for sulphates with barium chlorid solution. Pour off the excess of water and store the residual cream in a stoppered bottle. (C) Dry basic lead acetate {Home method). — This clarifying agent is obtained as a dry powdered salt and should contain 72.8% of lead, which corresponds to a com- position of 3Pb(C2H302)22PbO. Dissolve the normal or half -normal weight of the sugar solution in a flask with water and complete the volume. Add a small quantity of the dry salt and shake, then add more and shake again, repeating until completely precipitated but avoiding any excess. Of this salt 0.1346 gram is equivalent to 1 cc. of the basic lead acetate solution, described under (a). When molasses or any other substance producing a heavy precipitate is being clarified, some dry, coarse sand should be added to break up the balls of basic lead acetate and the precipitate. (This method is to have equal weight with the use of a solution of basic lead acetate in clarifying cane, sorghum, and beet products.) (d) Neutral lead acetate. — Prepare a saturated solution of neutral lead acetate and add it to the sugar solution before completing to volume. Its use is imperative when determining the reducing sugars in the solution used for polarization. (e) Basic lead nitrate {Merles' solution). — (1) Dissolve 250 grams of lead nitrate in water and make up to 500 cc. (2) Dissolve 25 grams of sodium hydroxid in water and make up to 500 cc. Add equal amounts of (1) and (2) to the sugar solution, shake, and add more if complete precipitation has not occurred, but avoid any excess. Then complete the volume with water. When this solution is used for clarification, the factor in the Clerget determination becomes 143.5 instead of 142.66. Vni] FOODS AND FEEDING STUFFS 83 DETERMINATION OF SUCROSE IN THE ABSENCE OF RAFFINOSE. (In the presence of much levulose, as in honeys and fruits products, the optical method for sucrose gives too high a result.) 14 By Polarization Before and After Inversion with Hydrochloric Acid. — Official. Dissolve the normal weight (26 grams) of the substance in water, add basic lead acetate carefully, avoiding any excess, then 1-2 cc. of alumina cream, shake, and dilute to 100 metric cc, filter, rejecting the first 20 cc. of the filtrate, cover the filter with a watch glass and, when sufficient filtrate is collected, polarize in a 200 mm. tube. The reading so obtained is the direct reading (P of formula given be- low) or polarization before inversion. For the invert reading, remove the lead from the solution either (1) by adding anhydrous potassium oxalate, a little at a time, to the remaining solution, avoiding an excess and removing the precipitated lead by filtration; or, (2) by adding anhydrous sodium carbonate under the same con- ditions. Introduce 50 cc. of the lead-free filtrate into a 100 cc. flask (if sodium carbonate was used for removing the lead, neutralize carefully the excess of sodium carbonate with a few drops of dilute hydrochloric acid) and add 25 cc. of water. Then add, little by little, while rotating the flask, 5 cc. of hydrochloric acid, (sp.gr. 1.20). Heat the flask after mixing, in a water bath kept at 70°C. The temperature of the solution in the flask should reach 67°-69°C. in 2|-3 minutes. Maintain a temperature of as nearly 69°C. as possible for 7-7J minutes, making the total time of heating 10 minutes. Remove the flask and cool the contents rapidly to 20°C. and dilute to 100 cc. Polarize this solution in a tube provided with a lateral branch and a water jacket, maintaining a temperature of 20°C. This reading must be multiplied by 2 to obtain the invert reading. If it is necessary to work at a tem- perature other than 20°C., which is allowable within narrow limits, the volumes must be completed and both direct and invert polarizations must be made at exactly the same temperature. The inversion may also be accomplished as follows: (1) To 50 cc. of the clarified solution, freed from lead, add 5 cc. of hydrochloric acid (sp. gr. 1.20) and set aside for 24 hours at a temperature not below 20°C.; or ,(2) If the temperature be above 25°C. set aside for 10 hours. Make up to 100 cc. at 20°C. and polarize as directed above. Calculate sucrose by one of the following formulas: For substances in which the invert solution contains more than 12 grams of invert sugar per 100 cc. — The following formula is to be used when substances like raw sugars are polarized: ^ 100 (P - I) . , . , S = in which T 142.66 - - S = per cent of sucrose; P = direct reading normal solution ; I = invert reading normal solution; T = temperature at which readings are made. For substances in lohich the concentration of the invert solution is less than 12 grams ■per 100 cc. — The following formula, which takes into account the concentration of the sugar in solution, should be used in all other cases. 84 METHODS OF ANALYSIS [Chap. 100 (P - I) • u- u S = =^ p Fp ^ in which 142.66 - 2 - 0-0065 [142.66 - ^ - (P S = per cent of sucrose; P = direct reading normal solution; I = invert reading normal solution; T = temperature. Bt/ Polarization Before and After Inversion with Invertase.— Tentative. 15 REAGENT. Invertase solution (Hudson Method.^)— Mix 1 kilo of pressed baker's or brewer's yeast with 1 liter of tap water and 50 cc. of toluene and keep at room temperature 2-3 days to allow autolysis to proceed to the stage of maximum inverting activity. Then add neutral lead acetate in slight excess, filter, precipitate the lead in the filtrate with hydrogen sulphid, filter again and then dialyze the filtrate thoroughly in a collodion sac. Preserve in an ice box the dialyzed solution with the addition of a little toluene to prevent the growth of micro-organisms. Note the optical activity of the invertase solution and correct the invert reading according to the amount of the solution used. 1 6 DETERMINATION. Dissolve the normal weight (26 grams) of the substance in water, clarify, make up to volume, and take the direct polarization (P) as directed under 14. If lead has been used as a clarifying agent, remove the excess of lead from the filtrate, with anhydrous sodium carbonate or potassium oxalate, and filter. To 50 cc. of the filtrate in a 100 cc. flask add acetic acid, drop by drop, until the reaction is acid to litmus, add 10 cc. of the invertase solution, fill the flask with water nearly to 100 cc. and let stand in a warm place (about 40°C.) overnight. Cool and make up to 100 cc. at 20°C. Polarize at 20°C. in a 200 mm. tube. Allow the solution to remain in the tube for an hour and repeat the polarization. If there is no change from the pre- vious reading, the inversion is complete, whereupon the reading and temperature of the solution are carefully noted. Correct the reading for the optical activity of the invertase solution and then multiply by 2. Calculate the percentage of sucrose by the following formula: 100 (P - I) . ... in which 142 0.0065 1142 (P 2 L 2 ■'] S = per cent of sucrose; P =« direct reading; I = invert reading; T = temperature at which invert reading is made. 17 DETERMINATION OF SUCROSE AND RAFFINOSE.-OFFICIAL. (Of value chiefly in the analysis of beet products.) If the direct reading is more than 1° higher than the per cent of sucrose as - al- culated by the formula given under 14, raffinose is probably present. Calculate sucrose and raffinose by the following formula of Herzfeld: Vin] FOODS AND FEEDING STUFFS 85 „ 0.5124 P-I ^ P-S . S = : R = in which 0.839 ' 1.852 P = direct reading normal solution; I = invert reading normal solution; S = per cent of sucrose; R = per cent of anhydrous raffinose. The above formula assumes that the polarizations are made at exactly 20°C. If the temperature (T) is other than 20°C., the following formula should be used: P (0.4724 + 0-002 T) - I 0.899 - 0.003 T P-S Having calculated S, then R = 1.852 CHEMICAL METHODS. 1 8 DETERMINATION OF SUCROSE FROM REDUCING SUGARS BEFORE AND AFTER INVERSION.— TENTATIV E. Determine the reducing sugars (clarification having been effected with neutral lead acetate, never with basic lead acetate), as directed under 25, and calculate to invert sugar from 27. Invert the solution as directed under 14 or 16, exactly neutralize the acid, and again determine the reducing sugars, but calculate them to invert sugar from the same table as referred to above, using the invert sugar column alone. Deduct the percentage of invert sugar obtained before inversion from that obtained after inversion, and multiply the difference by 0.95, the result being the per cent of sucrose. The solutions should be diluted in both determina- tions so that not more than 245 mg. of invert sugar are present in the amount taken for reduction. It is important that all lead be removed from the solution with potassium oxalate before reduction. Reducing Sugars, invert sugar. Approximate Volumetric Method for Rapid Work. — Tentative. 19 REAGENT. Soxhlet's Modification of Fehling's Solution. — Prepare by mixing, immediately before use. equal volumes of (a) and (b). (a) Copper sulphate solution. — Dissolve 34.639 grams of copper sulphate (CuSO^ 5H2O) in water, dilute to 500 cc. and filter through prepared asbestos. (b) Alkaline tartrate solution. — Dissolve 173 grams of Rochelle salts and 50 grams of sodium hydroxid in water, dilute to 500 cc, allow to stand for 2 days and filter through prepared asbestos. 20 STAND.^RDIZATION OF COPPER SOLUTION. Since the factor of calculation varies with the minute details of manipulation, every operator must determine a factor for himself, using a known solution of the pure sugar that he desires to determine, and keeping the conditions the same as those used for the detern^ination. 86 METHODS OF ANALYSIS [Chap. Standardize the solution for invert sugar in the following manner: Dissolve 4.75 grams of pure sucrose in 75 cc. of water, add 5 cc. of hydrochloric acid (sp. gr. 1.20) and invert as directed under 14. Neutralize the acid with sodium hydroxid solution and dilute to 1 liter. Ten cc. of this solution contain 0.050 gram of invert sugar, which should reduce 10 cc. of the reagent. The strength of the copper solution should never be taken as a constant, but should be checked against the sugar. 21 DETERMINATION. Place 10 CC. of the reagent in a large test tube and add 10 cc. of water. Heat to boiling, and add gradually small portions of the solution of the material to be tested until the copper has been completely reduced, boiling after each addition to com- plete the reaction. Two minutes' boiling is required for complete reduction when the full amount of sugar solution has been added in one portion. When the end is nearly reached and the amount of sugar solution to be added can no longer be judged by the color of the solution, remove a small portion of the liquid and filter rapidly into a small porcelain crucible or on a test plate; acidify with dilute acetic acid, and test for copper with dilute potassium ferrocyanid solution. The sugar solution should be of such strength as will give a burette reading of 15-20 cc, and the number of successive additions should be as small as possible. Soxhlet Volumetric Method. — Tentative. 22 REAGENT. The reagent used is described under 19. 23 DETERMINATION. Make a preliminary titration to determine the approximate percentage of reduc- ing sugar in the material under examination. Prepare a solution which contains approximately 1% of reducing sugar. Place in a beaker 100 cc. of the reagent and approximately the amount of the sugar solution for its complete reduction. Boil for 2 minutes. Filter through a folded filter and test a portion of the filtrate for copper by use of dilute acetic acid and dilute potassium ferrocyanid solution. Re- peat, varying the volume of sugar solution, until 2 successive amounts are found which differ by 0.1 cc, one giving complete reduction and the other leaving a small amount of copper in solution. The mean of these 2 readings is taken as the volume of the solution required for the complete precipitation of 100 cc. of the reagent. Under these conditions 100 cc. of the reagent require 0.494 gram of invert sugar for complete reduction. Calculate the percentage by the following formula: V = the volume of the sugar solution required for the complete reduction of 100 cc. of the reagent; W = the weight of the sample in 1 cc. of the sugar solution; 100 X 0.494 \ t ■ ^ — — = per cent of mvert sugar. VW GRAVIMETRIC METHODS Munson and Walker General Methods — Tentative. 24 REAGENTS. (a) Asbestos. — Digest the asbestos, which should be the amphibole variety, with dilute hydrochloric acid (1 to 3) for 2-3 days. Wash free from acid, digest for a Vin] FOODS AND FEEDING STUFFS 87 similar period with 10% sodium hydroxid solution, and then treat for a few hours with hot alkaline tartrate solution (old alkaline tartrate solutions that have stood for some time may be used for this purpose) of the strength employed in sugar de- terminations. Then wash the asbestos free from alkali, digest for several hours with dilute nitric acid (1 to 3) and, after washing free from acid, shake with water into a fine pulp. In preparing the Gooch crucible, make a film of asbestos i inch thick and wash thoroughly with water to remove fine particles of asbestos. If the precipitated cuprous oxid is to be weighed as such, wash the crucible with 10 cc. of alcohol, then with 10 cc. of ether, dry for 30 minutes at 100°C., cool in a desiccator and weigh. (b) The solution used is described under 19. 25 PRECIPITATION OF CUPROUS OXID. Transfer 25 cc. each of the copper sulphate and alkaline tartrate solutions to a 400 cc. beaker of alkali-resisting glass and add 50 cc. of reducing sugar solution, or, if a smaller volume of sugar solution is used, add water to make the final volume 100 cc. Heat the beaker upon an asbestos gauze over a Bunsen burner, regulate the flame so that boiling begins in 4 minutes, and continue the boiling for exactly 2 minutes. (It is important that these directions be strictly observed and, in order to regulate the burner for this purpose, it is advisable to make preliminary tests, using 50 cc. of the reagent and 50 cc. of water before proceeding with the actual determination.) Keep the beaker covered with a watch glass during the heating. Filter the cuprous oxid at once on an asbestos mat in a porcelain Gooch crucible, using suction. Wash the cuprous oxid thoroughly with water at a temperature of about 60°C., and either weigh directly as cuprous oxid as in 26, or, determine the amount of reduced copper by one of the methods under 29-34, respectively. Con- duct a blank determination, using 50 cc. of the reagent and 50 cc. of water, and, if the weight of cuprous oxid obtained exceeds 0.5 mg., correct the result of the reducing sugar determination accordingly. The alkaline tartrate solution deteriorates on standing and the amount of cuprous oxid obtained in the blank increases. Determination of Reduced Copper. 26 7. Direct Weighing of Cuprous Oxid. — Tentative. Prepare a Gooch as directed under 24 (a). Collect the precipitated cuprous oxid on the mat, as directed under 25, wash thoroughly with hot water, then with 10 cc. of alcohol, and finally with 10 cc. of ether. Dry the precipitate for 30 minutes in a water oven at the temperature of boiling water; cool and weigh. Calculate the weight of metallic copper. Obtain from 27 the weight of invert sugar equivalent to the weight of copper found. This method should be used only for determinations in pure sugar solutions. In all other products the copper of the cuprous oxid should be determined by one of the following methods, since the cuprous oxid is very apt to be contaminated with foreign matter. The number of milligrams of copper reduced by a given amount of reducing sugar differs when sucrose is present and when it is absent. In the tables the absence of sucrose is assumed except in the two columns under invert sugar, where one for mixtures of invert sugar and sucrose containing 0.4 gram of total sugar in 50 cc. of solution, and one for invert sugar and sucrose when the 50 cc. of solution contains 2 grams of total sugar are given, in addition to the column for invert sugar alone. METHODS OF ANALYSIS [Chap. 27 Table 1.— Munson and Walker's Table. For calculating dextrose, invert sugar alone, invert sugar in the presence of sucrose {0.4 gram and 2 grains total sugar), lactose {'wo forms), and maltose {anhydrous and crystallized). (Expressed in milligrams.] o "w INVERT SUGAR LACTI SE MALTOSE 1 6 3 o AND 8CCROSE 6 o 0 0 .J K 1 3 q O o s o "a O t o 1 K I > la o 1 6 3 1 6 o 10 8.9 4.0 4.5 1.6 3.8 4.0 5.9 6.2 11 9.8 4.5 5.0 4.5 4.7 6.7 7.0 12 10.7 4.9 5.4 2.5 5.1 5.4 7.5 7.9 13 11.5 5.3 5.8 3.0 5.8 6.1 8.3 8.7 14 12.4 5.7 6.3 3.4 6.4 6.8 9.1 9.5 15 13 3 6.2 6.7 3.9 7.1 7.5 9.9 10.4 16 14.2 6.6 7.2 4.3 7.8 8.2 10.6 11.2 17 15.1 7.0 7.6 4.8 8.4 8.9 11.4 12.0 18 16.0 7.5 8.1 5.2 9.1 9.5 12.2 12.9 19 16.9 7.9 8.5 5.7 9.7 10.2 13.0 13.7 20 17.8 8.3 8.9 6.1 10.4 10.9 13.8 14.6 21 18.7 8.7 9.4 6.6 11.0 11.6 14.6 15.4 22 19.5 9.2 9.8 7.0 11.7 12.3 15.4 18.2 22 23 20.4 9.6 10.3 7.5 12.3 13.0 16.2 17.1 23 24 21.3 10.0 10.7 7.9 13.0 13.7 17.0 17.9 24 25 22.2 10.5 11.2 8.4 13.7 14.4 17.8 18.7 25 26 23.1 10.9 11.6 8.8 14.3 15.1 18.6 19.6 28 27 24.0 11.3 12.0 9.3 15.0 15.8 19.4 20.4 27 28 24.9 11.8 12.5 9.7 15.6 16.5 20.2 21.2 28 29 25.8 12.2 12.9 10.2 16.3 17.1 21.0 22.1 29 30 26.6 12.6 13.4 10.7 4.3 16.9 17.8 21.8 22.9 30 31 27.5 13.1 13.8 11.1 4.7 17.6 18.5 22.6 23.7 31 32 28.4 13.5 14.3 11.6 5.2 18.3 19.2 23.3 24.6 32 33 29.3 13.9 14.7 12.0 5.6 18.9 19.9 24.1 25.4 33 34 30.2 14.3 15.2 12.5 6.1 19.6 20.6 24.9 26.2 34 35 31.1 14.8 15.6 12.9 6.5 20.2 21.3 25.7 27.1 35 36 32.0 15.2 16.1 13.4 7.0 20.9 22.0 26.5 27.9 36 37 32.9 15.6 16.5 13.8 7.4 21.5 22.7 27.3 28.7 37 38 33.8 16.1 16.9 14.3 7.9 22.2 23.4 28.1 29.6 38 39 34.6 16.5 17.4 14.7 8.4 22.8 24.1 28.9 30.4 39 40 35.5 16.9 17.8 15.2 8.8 23.5 24.8 29.7 31.3 40 41 36.4 17.4 18.3 15.6 9.3 24.2 25.4 30.5 32.1 41 42 37.3 17.8 18.7 16.1 9.7 24.8 26.1 31.3 32 9 42 43 38.2 18.2 19.2 16.6 10.2 25.5 26.8 32.1 33.8 43 44 39.1 18.7 19.6 17.0 10.7 26.1 27.5 32.9 34.6 44 45 40.0 19.1 20.1 17.5 11.1 26.8 28.2 33.7 35.4 45 46 40.9 19.6 20.5 17.9 11.6 27.4 28.9 34.4 36.3 46 47 41.7 20.0 21.0 18.4 12.0 28.1 29.6 35 2 37.1 47 48 42.6 20.4 21.4 18.8 12.5 28.7 30.3 36.0 37.9 48 49 43.5 20.9 21.9 19.3 12.9 29.4 31.0 36.8 38.8 49 50 44.4 21.3 22.3 19.7 13.4 30.1 31.7 37.6 39.6 50 51 45.3 21.7 22 8 20.2 13.9 30.7 32.4 38.4 40.4 51 52 46 2 22.2 23.2 20.7 14.3 31.4 33 0 39.2 41.3 52 53 47.1 22.6 23.7 21.1 14.8 32.1 33.7 40.0 42.1 53 54 48.0 23.0 24.1 21.6 . 15.2 32.7 34.4 40.8 42.9 54 55 48.9 23.5 24.6 22.0 15.7 33.4 35.1 41.6 43.8 55 56 49.7 23.9 25.0 22.5 16.2 34.0 35.8 42.4 44.6 56 57 50.6 24 3 25.5 22.9 16.6 34.7 36.5 43.2 45.4 57 58 51.5 24.8 25.9 23.4 17.1 35.4 37.2 44 0 46.3 58 59 52.4 25.2 26.4 23.9 17.5 36.0 37.9 44.8 47.1 59 60 53.3 25.6 26.8 24.3 18.0 36.7 38.6 45.6 48.0 60 61 54.2 26.1 27.3 24.8 18.5 37.3 39.3 46.3 48.8 61 62 55.1 26.5 27.7 25.2 18.9 38.0 40.0 47.1 49.6 62 63 56.0 27.0 28.2 25.7 19 4 38.6 40.7 47.9 50.5 63 64 56.8 27.4 28.6 26.2 19.8 39.3 41.4 48.7 51.3 64 vm] 27 FOODS AND FEEDING STUFFS Table 1.— Munson and Walker's Table.- [Expressed in milligrams.) -Continued. 1 i INVERT 80' AR AND SUCROSE LACTOSE MALT 8E a o p o T' .J M 1 3 a ? O o o o o U s a 1- § o s PS § la O 6 6 6 o a s: ;l s: ^ 3 u O Q 1 a > M 3 6 w 6 6 65 57.7 27.8 29.1 26.6 20.3 40.0 42.1 49.5 52.1 65 66 58.6 28 3 29.5 27.1 20.8 40.6 42.8 50.3 53.0 66 67 59.5 28.7 30.0 27.5 21.2 41.3 43.5 51.1 53.8 67 68 60.4 29.2 30.4 28.0 21.7 41.9 44.2 51.9 54 6 68 69 61.3 29.6 30.9 28.5 22.2 42.6 44.8 52.7 55.5 69 70 62.2 30.0 31.3 28.9 22.6 43 3 45.5 53 5 56.3 70 71 63.1 30.5 31.8 29.4 23.1 43.9 46.2 54.3 57.1 71 72 64.0 30.9 32.3 29.8 23.5 44.6 46.9 55.1 58.0 72 73 64.8 31.4 32 7 30.3 24.0 45.2 47.6 55.9 58.8 73 74 65.7 31.8 33.2 30.8 24.5 45.9 48.3 56.7 59.6 74 75 66.6 32.2 33.6 31.2 24.9 46.6 49.0 57.5 60.5 75 76 67.5 32.7 34.1 31.7 25.4 47.2 49.7 58.2 61.3 79 77 68.4 33.1 34.5 32.1 25.9 47.9 50.4 59.0 62.1 77 78 69.3 33.6 35.0 32.6 26.3 48.5 51.1 59.8 63.0 78 79 70.2 34.0 35.4 33.1 26.8 49.2 51.8 60.6 63.8 79 80 71.1 34.4 35.9 33.5 27.3 49.9 52.5 61.4 64.6 80 81 71.9 34.9 36.3 34.0 27.7 50.5 53.2 62.2 65 5 81 82 72.8 35.3 36.8 34.5 28.2 51.2 53.9 63.0 66.3 82 83 73.7 35 8 37.3 34.9 28.6 51.8 54.6 63.8 67.1 83 84 74.6 36.2 37.7 35.4 29.1 52.5 55.3 64.6 68.0 84 85 75.5 36.7 38.2 35.8 29.6 53.1 56.0 65.4 68.8 85 86 76.4 37.1 38.6 36.3 30.0 53.8 56.6 66.2 69.7 86 87 77.3 37.5 39.1 36.8 30.5 54.5 57.3 67.0 70.5 87 88 78.2 38.0 39.5 37.2 31.0 55.1 58.0 67.8 71.3 88 79.1 38.4 40.0 37.7 31.4 55.8 58.7 68.5 72.2 80 90 79.9 38.9 40.4 38.2 31.9 56.4 59.4 69.3 73.0 90 91 80.8 39.3 40.9 38.6 32.4 57.1 60.1 70.1 73.8 91 92 81.7 39.8 41.4 39.1 32.8 57.8 60.8 70.9 74.7 92 93 82.6 40 2 41 8 39.6 33.3 58.4 61.5 71.7 75 5 93 94 83.5 40.6 42.3 40.0 33.8 59.1 62.2 72.5 78.3 94 95 84.4 41.1 42.7 40.5 34.2 59.7 62.9 73.3 77.2 95 96 85.3 41.5 43.2 41.0 34.7 60.4 63.6 74.1 78.0 96 97 86.2 42.0 43.7 41.4 35.2 61.1 64.3 74.9 78.8 97 98 87.1 42.4 44.1 41.9 35.6 61.7 65.0 75.7 79.7 98 99 87.9 42.9 44.6 42.4 36.1 62.4 65.7 76.5 80.5 99 100 88.8 43.3 45.0 42.8 36.6 63.0 66.4 77.3 81.3 100 101 89 7 43.8 45 5 43.3 37.0 63.7 67.1 78.1 82.2 101 102 90.6 44.2 46.0 43.8 37.5 64.4 67.8 78.8 83.0 102 103 91.5 44.7 46.4 44.2 38.0 65.0 68.5 79.6 83.8 103 104 92.4 45.1 46.9 44.7 38.5 65.7 69.1 80.4 84.7 104 105 93.3 45.5 47.3 45.2 38.9 66.4 69.8 81.2 85.5 105 106 94.2 46.0 47.8 45 6 39.4 67.0 70.5 82.0 86.3 106 107 95.0 46.4 48.3 46.1 39.9 67.7 71.2 82.8 87.2 107 108 95.9 46.9 48.7 46.6 40.3 68.3 71.9 83.6 88.0 108 109 96.8 47.3 49.2 47.0 40.8 69.0 72.6 84.4 88.8 109 110 97.7 47.8 49.6 47.5 41.3 69.7 73.3 85.2 89.7 110 111 98.6 48.2 50.1 48.0 41.7 70.3 74.0 86.0 90.5 111 112 99.5 48. 7 50.6 48.4 42.2 71.0 74.7 86.8 91.3 112 113 100.4 49.1 51.0 48.9 42.7 71.6 75.4 87.6 92.2 113 114 101.3 49.6 51.5 49.4 43.2 72.3 76.1 88.4 93.0 114 115 102.2 50.0 51.9 49.8 43.6 73.0 76.8 89 2 93 9 115 116 103.0 50.5 52.4 50.3 44 1 73.6 77.5 90 0 94.7 116 117 103 9 50.9 52.9 50.8 44.6 74.3 78.2 90.7 95.5 117 118 104.8 51.4 53.3 51.2 45.0 75.0 78.9 91.5 96.4 118 119 105.7 51.8 53.8 51.7 45.5 79.6 92.3 97.2 119 90 27 METHODS OF ANALYSIS Table 1.— Munson and Walker's Table.— Continued. [Expressed in milligrams.! [Chap. 1 6 K B< 8 g o m a PS •j _ 0 o 1 2 i 3 1 9 a 8 s § i. iu o 6 8 6 00 s I a Ui u M 3 i a s o B o Q 2 2" c." 6 6 d o & 285 253.2 129.8 133.9 1,32.7 126.6 186.2 196.0 223.7 235.5 285 286 254.0 130.3 134.4 133.2 127.1 186.9 196.7 224.5 2.36.3 286 287 254.9 130.8 134.9 133.7 127.6 187.5 197.4 225.3 237.1 287 288 255.8 131.3 135.4 134.3 128.1 188.2 198.1 226.1 238.0 288 289 256.7 131.8 135.9 134.8 128.6 188.9 198.8 226.9 238.8 289 290 257.6 132.3 136.4 135.3 129.2 189.5 199.5 227.6 239.6 290 291 258.5 132.7 136.9 135.8 129.7 190.2 200.2 228.4 240.5 291 392 259.4 133.2 137.4 136 3 130.2 190.9 200.9 229.2 241.3 292 293 260.3 133.7 137.9 136.8 130.7 191.5 201.6 230.0 242.1 293 294 261.2 134.2 138.4 137.3 131.2 192.2 202.3 230.8 242.9 294 295 262.0 134.7 138.9 137.8 1.31.7 192.9 203.0 231.6 243.8 295 296 262.9 135.2 139.4 138.3 1.32.2 193.6 203.7 232.4 244.6 296 297 263.8 135.7 140.0 13S.8 132.7 194.2 204.4 233.2 245.4 297 298 264.7 136.2 140.5 139.4 133.2 194.9 205.1 234.0 246.3 298 299 265.6 136.7 141.0 139.9 133.7 195.6 205.8 234.8 247.1 299 300 266.5 137 2 141.5 140.4 134.2 196.2 206.6 235.5 247.9 300 301 267.4 137.7 142.0 140.9 134.8 196.9 207.3 236.3 248.8 301 302 268.3 138.2 142.5 141.4 135.3 197.6 208.0 237.1 249.6 302 303 269.1 138.7 143.0 141.9 135.8 198.3 208.7 237.9 250.4 303 304 270.0 139.2 143.5 142.4 136.3 198.9 209.4 238.7 251.3 304 305 270.9 139.7 144.0 142.9 136.8 199.6 210.1 239.5 252.1 305 306 271.8 140.2 144.5 143.4 137.3 200.3 210.8 240.3 252.9 306 307 272.7 140.7 145.0 144.0 137.8 201.0 211.5 241.1 2.53.8 307 308 273.6 141.2 145.5 144.5 138.3 201.6 212.2 241.9 254.6 308 309 274.5 141.7 146.1 145.0 138.8 202.3 212.9 242.7 255.4 309 310 275.4 142.2 146.6 145.5 139.4 203.0 213.7 243.5 256.3 310 311 276.3 142.7 147.1 146.0 139.9 203.6 214.4 244.2 257.1 311 312 277.1 143.2 147.6 146.5 140.4 204.3 215.1 245.0 257.9 312 313 278.0 143.7 148.1 147.0 140.9 205.0 215.8 245.8 258.8 313 314 278.9 144.2 148.6 147.6 141.4 205.7 216.5 246.6 259.6 314 315 279.8 144.7 149.1 148.1 141.9 206.3 217.2 217.4 260.4 315 316 280.7 145.2 149.6 148.6 142 4 207.0 217.9 248.2 261.2 316 317 281.6 145.7 150.1 149.1 143.0 207.7 218.6 249.0 262.1 317 3ia 282.5 146.2 150.7 149.6 143.5 208.4 219.3 249.8 262.9 318 319 283.4 146.7 151.2 150.1 144.0 209.0 220.0 250.6 263.7 319 320 284.2 147.2 151.7 150.7 144.5 209.7 220.7 2.51.3 264.6 320 321 285.1 147.7 152.2 151.2 145.0 210.4 221.4 2.52.1 265.4 321 322 286.0 148.2 152.7 151.7 145.5 211.0 222.2 252.9 266.2 322 323 286.9 148.7 153.2 152.2 146.0 211.7 222.9 253.7 267.1 323 324 287.8 149.2 153.7 152.7 146.6 212.4 223.6 254.5 267.9 324 325 288.7 149.7 154.3 153.2 147.1 213.1 224.3 255.3 268.7 325 326 289.6 150.2 1.54.8 153.8 147.6 213.7 225.0 256.1 269.6 326 327 290.5 150.7 1.55.3 154.3 148.1 214.4 225.7 256.9 270.4 327 328 291.4 151.2 155.8 154.8 148.6 215.1 226.4 257.7 271.2 328 329 292.2 151.7 156.3 155.3 149.1 215.8 227.1 258.5 272.1 329 330 293.1 152.2 156.8 155.8 149.7 216.4 227.8 259.3 272.9 330 331 294.0 1.52.7 157.3 156.4 150 2 217.1 228.5 260.0 273.7 331 332 294.9 153.2 157.9 1.56.9 150.7 217.8 229.2 260.8 274.6 332 333 295.8 153.7 158 4 157.4 151.2 218.4 230.0 261 6 275 4 333 334 296.7 154.2 158.9 157.9 151.7 219.1 230.7 262.4 276.2 334 335 297.6 154.7 159.4 158.4 152.3 219.8 231.4 263.2 277.0 335 336 208.5 155.2 159.9 159.0 152.8 220.5 232.1 264 0 277.9 336 337 299.3 155.8 160.5 1.59 5 153.3 221.1 232.8 264.8 278.7 337 338 300.2 156.3 161.0 160.0 153.8 221.8 233.5 265.6 279.5 338 339 301.1 156.8 161.5 160.5 154.3 222.5 234.2 266.4 280.4 339 94 27 METHODS OF ANALYSIS Table 1.— Munson and Walker-s Table.- (Expressed in milligrams.] [Chap. -Continued. f 1 INVERT 8(;OAR AND 8LCR09B LACTOSE UAI-TOaE 3 o _ O >j le a 0 s s 1 "a u e g 8 1 i ■< O a S > 2 o h o O ?: 6 K 6 1 j 340 302.0 157.3 162.0 161.0 154.8 223.2 234.9 267.1 281.2 340 341 302.9 157.8 162.5 161.6 155.4 223.8 235.6 267.9 282.0 341 342 303.8 158.3 163.1 162.1 155.9 224.5 236,3 268.7 282.9 342 343 304.7 158.8 163.6 162.6 156.4 225.2 237,0 269.5 283.7 343 344 305.6 159.3 164.1 163.1 156.9 225,9 237.8 270.3 284.5 344 345 306.5 159.8 164.6 163.7 157.5 226,5 238.5 271.1 285.4 345 346 307.3 160.3 165.1 164.2 158.0 227,2 239.2 271.9 286 2 340 347 308.2 160.8 165,7 164.7 158.5 227,9 239.9 272.7 2.87.0 347 348 309.1 161.4 166.2 165.2 159.0 228,5 240.6 273.5 287.9 348 349 310.0 161.9 166.7 165.7 159.5 229.2 241.3 274.3 288.7 349 350 310.9 162 4 167.2 166.3 160.1 229.9 242.0 275.0 289.5 350 351 311.8 162.9 167.7 166.8 160.6 230.6 242,7 275.8 290 4 351 352 312.7 163.4 168.3 167.3 161.1 231.2 243,4 276.6 291.2 352 353 313.6 163 9 168.8 167.8 161.6 231.9 244,1 277.4 292.0 353 354 314.4 164.4 169.3 168.4 162.2 232.6 244.8 278.2 292.8 354 355 315.3 164.9 169.8 168.9 162.7 233.3 245.6 279.0 293.7 355 356 316.2 165.4 170.4 169.4 163.2 233.9 246.3 279.8 294.5 358 357 317.1 166 0 170.9 170,0 163.7 234.6 247.0 280.6 295.3 357 358 318. 0 166.5 171.4 170.5 164.3 235.3 247.7 281.4 296 2 358 359 318.9 167.0 171.9 171.0 164.8 236.0 248.4 282.2 297.0 359 360 319.8 167.5 172.5 171.5 165,3 236.7 249.1 282.9 297.8 360 361 320.7 168.0 173.0 172.1 165.8 237.3 249.8 283.7 298.7 381 362 321.0 168.5 173.5 172.6 166.4 238.0 250.5 284.5 299.5 382 363 322.4 169 0 174.0 173.1 166.9 238.7 251.2 285.3 300.3 363 364 323.3 169.6 174.6 173.7 167.4 239.4 252.0 286.1 301.2 384 365 324.2 170.1 175.1 174.2 167.9 240.0 252.7 286.9 302.0 365 366 325.1 170.6 175.6 174.7 168.5 240.7 253.4 287.7 302.8 368 367 326.0 171.1 176.1 175.2 169.0 241.4 254.1 288.5 303.6 367 368 326.9 171.6 176.7 175.8 169.5 242.1 254.8 289.3 304.5 368 369 327.8 172.1 177.2 176.3 170.0 242.7 255.5 290.0 305.3 369 370 328.7 172.7 177.7 176.8 170.6 243.4 256,2 290.8 306.1 370 371 329.5 173.2 178.3 177.4 171.1 244.1 256,9 291.6 307 0 371 372 330 4 173.7 178.8 177.9 171.6 244.8 257,7 292.4 307.8 372 373 331.3 174.2 179.3 178.4 172.2 245.4 258.4 293.2 308.6 373 374 332.2 174.7 179.8 179.0 172.7 246.1 259.1 294.0 309.5 374 375 333.1 175.3 180 4 179.5 173.2 246.8 259.8 294.8 310.3 375 376 334.0 175.8 180.9 180.0 173.7 247.5 260.5 295.6 311.1 376 377 334.9 176.3 181.4 180.6 174.3 248 1 201.2 296.4 312.0 377 378 335.8 176.8 182.0 181.1 174.8 248.8 261.9 297.2 312.8 378 379 336.7 177.3 182.5 181.6 175.3 249.5 262.6 297.9 313.6 379 380 3.37 5 177.0 183.0 182.1 175,9 250.2 263.4 298,7 314.5 380 381 338 4 178.4 183.6 182.7 176,4 250.8 264.1 299,5 315.3 381 382 339.3 178 9 184.1 183.2 176,9 251.5 264.8 300,3 316.1 382 383 340 2 179,4 184.6 183 8 177,5 252.2 265.5 301,1 316.9 383 384 341.1 180.0 185.2 184.3 178.0 252.9 266.2 301,9 317.8 384 385 342.0 180.5 185.7 184.8 178.5 253.6 266.9 302,7 318.6 385 386 342 9 181.0 186.2 . 185.4 179.1 254.2 267.6 303,5 319.4 386 387 .343 8 181.5 186.8 185.9 179.6 254.9 268.3 304.2 320.3 387 388 344.6 182.0 187.3 186.4 180.1 255.6 269.0 305.0 321.1 388 389 345.5 182.6 187.8 187.0 180.6 256.3 269.8 305.8 321.9 389 390 346.4 183.1 188.4 187.5 181.2 256.9 270.5 306.6 322.8 390 891 347 3 183.6 188.9 188.0 181.7 257.6 271.2 307.4 323.6 391 392 318 2 184.1 189 4 188.8 182.3 258.3 271.9 308.2 324.4 392 303 340 1 184.7 190.0 189.1 182.8 259.0 272.0 309.0 325 2 393 394 350.0 185.2 190.5 189.7 183.3 259.6 273.3 309.8 326.1 394 VIII] 27 FOODS AND FEEDING STUFFS Table 1.— Munson and Walker-s Table.— Continued. (Expressed in milligrams.) 95 1 i INVERT 8UO.\R AND SUCROSE LACTOSE MALTOSE 5 o _ 0 5 2 a _ ? •< 2 q 0 a y, o o £ "5 a § g Q S k 5 to" o 1 0 1 0 i 6 8 § g 0 395 350.9 185.7 191.0 190.2 183.9 260.3 274.0 310.6 326.9 395 398 351.8 186.2 191.6 190.7 184.4 261.0 274 7 311.4 327 7 396 397 352.6 186.8 192 1 191.3 184.9 261.7 275.5 312 1 328.6 397 398 353.5 187.3 192.7 191 8 185.5 262.3 276.2 312.9 329.4 398 399 354.4 187.8 193.2 192.3 186.0 263.0 276.9 313.7 330.2 399 400 355.3 188.4 193.7 192.9 186.5 263.7 277.6 314.5 331 1 400 401 356.2 188.9 194.3 193.4 187.1 264.4 278.3 315 3 331.9 401 402 357.1 189.4 194.8 194.0 187.6 265.0 279.0 316.1 332.7 402 403 3.58.0 189.9 195.4 194.5 188.1 265.7 279 7 31G.9 333.6 403 404 358.9 190.5 195.9 195.0 188.7 266.4 280.4 317.7 334.4 404 405 .359.7 191.0 196.4 195.6 189.2 267.1 281.1 318.5 335 2 405 406 360.6 191.5 197.0 196.1 189.8 267 8 281.9 319.2 .3.36 0 408 407 .361.5 192.1 197.5 196.7 190.3 268.4 282.6 320.0 338 9 407 408 362.4 192.6 198.1 197.2 190.8 269 1 283.3 320.8 337.7 408 409 363.3 193.1 198.6 197.7 191.4 269.8 284.0 321.6 338.5 409 410 364.2 193.7 199.1 198.3 191.9 270.5 284.7 .322.4 339.4 410 411 365.1 194 2 199.7 198.8 192.5 271.2 285.4 323 2 340.2 411 412 366.0 194.7 200.2 199.4 193.0 286.2 324.0 341.0 412 413 366.9 195.2 20O.S 199.9 193.5 272:5 286.9 324.8 341.9 413 414 367.7 195.8 201.3 200.5 194.1 273.2 287.6 325.6 342.7 414 415 368.6 196.3 201.8 201.0 194.6 273.9 288.3 326.3 343.5 415 416 369.5 196.8 202.4 201.6 195.2 274.6 289.0 327.1 344.4 416 417 370.4 197.4 202.9 202.1 195.7 275.2 289.7 327.9 345.2 417 418 371.3 197.9 203.5 202.6 196.2 275.9 290.4 328.7 .346.0 418 419 372.2 198.4 204.0 203.2 196.8 276.6 291.2 329.5 346.8 419 420 373.1 199.0 204.6 203.7 197 3 277 3 291.9 330.3 347.7 42Q 421 374.0 199.5 205.1 204.3 197.9 277.9 292.6 331 1 348.5 421 422 374 8 200.1 205.7 204.8 198.4 278.6 293.3 331.9 349.3 422 423 .375.7 20T.6 206.2 205.4 198.9 279.3 294.0 3.32.7 3.50.2 423 424 376.6 201.1 206.7 205.9 199.5 280.0 294.7 333.4 351.0 424 425 377.5 201.7 207.3 206.5 200.0 280.7 295.4 334.2 351.8 425 426 378.4 202.2 207.8 207.0 200.6 281.3 296.2 335.0 352.7 420 427 379.3 202.8 208.4 207.6 201.1 282.0 296.9 3.35.8 3,53.5 427 428 380.2 203.3 208.9 208.1 201.7 282.7 297.6 3,36 6 354.3 428 429 381.1 203.8 209.5 208.7 202.2 283 4 298.3 337.4 355.1 429 430 382.0 204.4 210.0 209.2 202.7 284.1 299.0 338.2 356 0 430 431 382.8 204.9 210.6 209 8 203.3 284.7 299.7 339.0 356.8 431 432 383.7 205.5 211.1 210.3 203.8 285.4 300 5 339.7 357.6 432 433 384.6 206.0 211.7 210.9 201.4 286.1 301.2 340.5 358.5 433 434 385.5 206.5 212.2 211.4 204.9 286.8 301.9 341.3 359.3 434 435 386.4 207.1 212.8 212.0 205.5 287.5 .302.6 342.1 360.1 435 436 387.3 207.6 213.3 212.5 206.0 288.1 303.3 342.9 361.0 436 437 388.2 208.2 213.9 213.1 205 6 288.8 304.0 343.7 361.8 437 438 389 1 208.7 214.4 213.6 207.1 289.5 304.7 344.5 362 6 438 439 390.0 209.2 215.0 214.2 207.7 290.2 305.5 345 3 363.4 439 440 390.8 209.8 215.5 214.7 208.2 290.9 306.2 346.1 364 3 440 441 391.7 210.3 216.1 215.3 203.8 291.5 306.9 346.8 365 1 441 442 392.6 210 9 216.6 215.8 209.3 292.2 307.6 347.6 365 9 442 443 393.5 211.4 217.2 216.4 209.9 292.9 308.3 348.4 366 8 443 444 394.4 212.0 217.8 216.9 210.4 293.6 309.0 349.2 367 6 444 445 395.3 212.5 218.3 217.5 211.0 294.2 309.7 350.0 ,368.4 445 446 396.2 213.1 218.9 218 0 211 5 294 9 310.5 350.8 369.3 446 447 397.1 213.6 219.4 218.6 212.1 295.6 311 2 351.6 370 1 447 448 397 9 214 1 220.0 219 1 212.6 296.3 311.9 352.4 370 9 448 449 398.8 214.7 220.5 219.7 213.2 297.0 312.6 353.2 371.7 449 96 27 METHODS OF ANALYSIS Table l.— Munson and Walker's Table.- [Expressed in milligrams.) [Chap. -Continued. q i INVERT SUGAR AND SUCROSE LACTOSE MALTOSE 0 3 o •a - 9 Q X C u 1 0 0 ^ 2 0 0 0 0 m w s CD S p o H S u e i- 0 0 0 0 0 o 0. 1 a 1 3 03 C3 u 6 6 1 6 0 K p 450 399.7 215.2 221 1 220,2 213.7 297.6 313.3 353.9 372.6 450 451 400.6 215.8 221.6 220,8 214.3 298.3 314,0 354,7 373.4 451 452 401.5 216.3 222.2 221.4 214,8 299.0 314,7 355,5 374.2 452 453 402,4 216.9 222.8 221,9 215,4 299,7 315,5 356,3 375.1 453 454 403.3 217.4 223.3 222.5 215.9 300.4 316.2 357.1 375.9 454 455 404.2 218.0 223,9 223,0 216.5 301,1 316.9 357.9 376.7 455 456 405.1 218,5 224 4 223,6 217.0 301,7 317.6 358.7 377.6 456 457 405.9 219,1 225,0 224,1 217.6 302.4 318.3 359.5 378.4 457 458 406.8 219.6 225.5 224.7 218.1 303.1 319.0 360.3 379.2 458 459 407.7 220.2 226.1 225.3 218.7 303.8 319.8 361.0 380.0 459 460 408,6 220.7 226.7 225.8 219.2 304.5 320.5 361.8 380.9 460 461 409,5 221.3 227.2 226.4 219.8 305.1 321.2 362.6 381,7 461 462 410,4 221.8 227.8 226.9 220.3 305.8 321.9 363.4 382 5 462 463 411,3 222.4 228.3 227.5 220.9 306,5 322.6 364.2 383.4 463 464 412,2 222.9 228.9 228.1 221.4 307,2 323.4 365.0 384.2 464 465 413,0 223.5 229.5 228.6 222.0 307.9 324.1 365.8 385.0 465 466 413,9 224.0 230.0 229.2 222.5 308.6 324.8 366.6 385.9 466 467 414 8 224.6 230.6 229,7 223.1 309.2 325.5 367.3 386.7 467 468 415,7 225.1 231.2 230.3 223.7 309.9 326.2 368.1 387,5 468 469 416.6 225.7 231.7 230.9 224.2 310.6 326.9 368.9 388,3 469 470 417.5 226.2 232.3 231.4 224.8 311.3 327.7 369,7 3S9.2 470 471 418,4 226.8 232.8 232.0 225.3 312.0 328.4 370,5 390,0 471 472 419,3 227.4 233.4 232.5 225.9 312.6 329.1 371,3 390,8 472 473 420.2 227,9 234.0 2.33.1 226.4 313.3 329,8 372,1 391,7 473 474 421,0 228,5 234.5 233,7 227.0 314.0 330.5 372.9 392,5 474 475 421,9 229,0 235.1 234,2 227.6 314.7 331,3 373.7 393,3 475 476 422 8 229,6 235.7 234,8 228.1 315.4 332,0 374.4 394,2 476 477 423,7 230.1 236.2 235,4 228.7 316.1 332,7 375.2 395,0 477 478 424,6 230.7 236.8 235,9 229.2 316,7 333.4 376,0 395.8 478 479 425.5 231.3 237.4 236,5 229,8 317.4 334.1 376,8 396.6 479 480 426.4 031 8 237.9 237,1 230,3 318.1 334.8 377,6 397.5 480 481 427.3 232; 4 238.5 237,6 230,9 318.8 335.6 378,4 398.3 481 482 428,1 232.9 239.1 .238.2 231,5 319,5 336 3 379,2 399.1 482 483 429,0 233.5 239,6 238,8 232,0 320.1 337.0 380.0 400.0 483 484 429,9 234.1 240,2 239,3 232,6 320.8 337.7 380.7 400.8 484 485 430,8 234.6 240,8 239,9 233,2 321.5 338.4 381.5 401.6 485 486 431.7 235.2 241,4 240.5 2.33,7 322.2 339,1 382.3 402.4 486 487 432.6 235,7 241,9 241,0 2.34.3 322.9 339.9 383,1 403,3 487 488 433,5 236,3 242,5 241,6 234.8 323.6 340,6 383,9 404,1 488 489 434,4 236.9 243.1 242,2 235,4 324.2 341,3 384,7 404,9 489 490 435.3 237.4 243.6 242,7 236.0 324.9 342,0 385.5 405,8 490 28 II. A. H. Low Volumetric Method, Modified.^ — Tentative. Standard thiosulphate solution. — Prepare a solution of sodium thiosulphate containing 19 grams of pure crystals in 1 liter. Weigh accurately about 0.2 gram of pure copper foil and place in a flask of 250 cc. capacity. Dissolve by warming with 5 cc. of a mixture of equal volumes of strong nitric acid and water. Dilute to 50 cc, boil to expel the red fumes, add 5 cc. of strong bromin water, and boil Vni] FOODS AND FEEDING STUFFS 97 until the bromin is completely driven off. Remove from the heat and add a slight excess of strong ammonium hydroxid (about 7 cc. is required). Again boil until the excess of ammonia is expelled, as shown by a change of color of the liquid, and a partial precipitation. Then add a slight excess of strong acetic acid (3 or 4 cc. of 80% acid) and boil for a minute. Cool to room temperature and add 10 cc. of 30% potassium iodid solution. Titrate at once with the thiosulphate solution until the brown tinge has become weak, then add sufficient starch indicator [VII, 3 (a)l to produce a marked blue coloration. Continue the titration cautiously until the color due to free iodin has entirely vanished. The blue color changes to- ward the end to a faint lilac. If at this point the thiosulphate be added drop by drop and a little time allowed for complete reaction after each addition, there is no diffi- culty in determining the end point within a single drop. One cc. of the thiosulphate solution will be found to correspond to about 0.005 gram of copper. 29 DETERMINATION. After washing the precipitated cuprous oxid, cover the Gooch with a watch glass and dissolve the oxid by means of 5 cc. of warm nitric acid (1 to 1) poured under the watch glass with a pipette. Catch the filtrate in a 250 cc. flask, wash the watch glass and Gooch free of copper, using about 50 cc. of water. Boil to expel red fumes, add 5 cc. of bromin water, boil off the bromin, and proceed exactly as in 28. 30 ///. Volumetric Permanganate Method. — Tentative. Filter and wash the cuprous oxid as directed under 25. Transfer the asbestos film to the beaker, add about 30 cc. of hot water, and beat the precipitate and asbes- tos thoroughly. Rinse the crucible with 50 cc. of a hot saturated solution of ferric sulphate in 20% sulphuric acid, receiving the rinsings in the beaker containit)g the precipitate. After the cuprous oxid is dissolved, wash the solution into a large Erlenmeyer flask and immediately titrate with a standard solution of potassium permanganate, 1 cc. of which should he equivalent to 0.010 gram of copper. Stand- ardize this solution by making 6 or more determinations with the same sugar solu- tion, titrating one half of the precipitates obtained, and determining the copper in the others by electrolysis. The average weight of copper obtained by electrolysis, divided by the average number of cc. of permanganate solution required for the titrations, gives the weight of copper equivalent to 1 cc. of the standard perman- ganate solution. A solution standardized with iron or oxalic acid will give too low a result. 31 IV. Electrolytic Deposition from Sulphuric Acid Solution. — Tentative. Filter the cuprous oxid in a Gooch, wash the beaker and the precipitate thoroughly with hot water without transferring the precipitate to the filter. Wash the asbestos film and the adhering cuprous oxid into the beaker by means of hot dilute nitric acid. After the copper is all in solution, refilter through a thin film of asbestos in a Gooch and wash thoroughly with hot water. Add 10 cc. of sulphuric acid (1 to 4), and evaporate the filtrate on the steam bath until the copper salt has largely crystal- lized. Heat carefully on a hot plate or over asbestos until the evolution of white fumes shows that the excess of nitric acid is removed. Add 8-10 drops of nitric acid (sp. gr. 1.42) and rinse into a 100-125 cc. platinum dish. Deposit the copper by 98 METHODS OF ANALYSIS [Chap. electrolysis. Wash thoroughly with water, then break the current, wash with alco- hol and ether successively, dry at about 50°C., and weigh. If preferred, the elec- trolysis can be conducted in a beaker, the copper being deposited upon a weighed platinum electrode. 32 V. Electrolytic Deposition from Sulphuric and Nitric Acid S dulion. — Tenfative. Filter and wash as directed under 31 . Transfer the asbestos film from the cru- cible to the beaker by means of a glass rod and rinse the crucible with about 30 cc. of a boiling mixture of dilute sulphuric and nitric acids, containing 65 cc. of sul- phuric acid (sp. gr. 1.84) and 50 cc. of nitric acid (sp. gr. 1.42) per liter. Heat and agitate until solution is complete; filter and electrolyze as under 31 . 33 VI. Electrolytic Deposition from Nitric Acid Sdution. — Tentative. Filter and wash as directed under 31 . Transfer the asbestos film and adhering oxid to the beaker. Dissolve the oxid still remaining in the crucible by means. of 2 cc. of nitric acid (sp. gr. 1.42), adding it with a pipette and receiving the solution in the beaker containing the asbestos film. Rinse the crucible with a jet of water, allowing the rinsings to flow into the beaker. Heat the contents of the beaker until the copper is all in solution, filter, dilute the filtrate to a volume of 100 cc. or more, and electrolyze. When a nitrate solution is electrolyzed, the first washing of the deposit should be made with water acidulated with sulphuric acid, in order to remove all the nitric acid before the current is interrupted. 34 VII. Reduction in Hydrogen. — Tentative. Deposit an asbestos film on a perforated platinum disc or cone contained in a hard glass filtering tube, wash free from loose fibers, dry and weigh. Through this tube, previously moistened, filter the cuprous oxid immediately, using suction. Transfer the cuprous oxid to the tube through a removable funnel, and wash thor- oughly with hot water, alcohol and ether successively. After drying, connect the tube with a supply of dry hydrogen, heat gently until the cuprous oxid is com- pletely reduced to metallic copper, cool in the current of hydrogen, and weigh. If preferred, a Gooch crucible may be used for the filtration. Herzfeld Gravimetric Method. — Tentative. Method I. (For materials containing 1.5% or less of invert sugar and 98.5% or more of sucrose.) 35 REAGENTS. The reagents and solutions used are described under 24. 36 DETERMINATION. Prepare the solution of the material to be examined so as to contain 20 grams in 100 cc, free from suspended impurities by filtration and from soluble impurities by neutral lead acetate, removing the excess of lead by means of sodium carbonate. Place 50 cc. of the reagent and 50 cc. of the sugar solution in a 250 cc. beaker. Heat this mixture at such a rate that approximately 4 minutes are required to bring it to the boiling point, and boil for exactly 2 minutes. Add 100 cc. of cold, recently boiled, water. Filter immediately through asbestos, and determine the copper by one of the methods under 26, 29-34, respectively. Obtain the corresponding oercentage of invert sugar from 37. VIII] FOODS AND FEEDING STUFFS 37 Table 2.— Herzfeld'S Table. For the determination of invert sugar in materials containing 1.5%, or less, of invert sugar and 98.5%, or more, of sucrose. COPPER C PPER COPPER BEinCED BT 10 ORAM8 INVERT SUGAR REDUCED BT 10 ORAM3 IKVERT SUGAR REDUCED BT 10 < 3.256 = 4.45 100 - R = = 100- 95.1= I = - 4.9 R:I = 95.1:4.9 By consulting the table it will be seen that the vertical column headed l/iO is nearest to Z, 145, and the horizontal column headed 95: 5 is nearest to the ratio of R to I, 95.1 : 4.9. Where these columns meet, we find the factor 51.2 which enters into the final calculation: CuF W 0.290 X 51.2 3.256 = 4.56 per cent of invert sugar. In case there is no sucrose present, the following table may be used instead of the factors given in 40. VIII] 41 foods and feeding stuffs Table 4.— Meissl-s Table. ^ For the determination of invert sugar alonf,: [According to Wein.] [Expressed in milligrams.) 101 COPPER INVERT SUGAR COPPER INVERT SUGAR COPPER INVERT SUGAR COPPER 1N\ ERT SUGAR 90 46.9 135 70.8 180 95.2 225 120.4 91 47.4 136 71.3 181 95.7 226 120.9 92 47.9 137 71.9 182 96.2 227 121.5 93 48.4 138 72.4 183 96.8 228 122.1 94 48.9 139 72.9 184 97.3 229 122.6 95 49.5 140 73.5 185 97.8 230 123.2 96 50.0 141 74.0 186 98.4 231 123.8 97 50.5 142 74.5 187 99.0 232 124.3 98 51.1 143 75.1 188 99.5 233 124.9 99 51.6 144 75.6 189 100.1 234 125.5 100 52.1 145 76.1 190 100.6 235 126.0 101 52.7 146 76.7 191 101.2 236 126.6 102 53.2 147 77.2 192 101.7 237 127.2 103 53.7 148 77.8 193 102.3 238 127.8 104 54.3 149 78.3 194 102.9 239 128.3 105 54.8 150 78.9 195 103.4 240 128.9 106 55.3 151 79.4 196 104.0 241 129.5 107 55.9 152 80.0 197 104.6 242 130.0 108 56.4 153 80.5 198 105.1 243 130.6 109 56.9 154 81.0 199 105.7 244 131.2 110 57.5 155 81.6 200 106.3 245 131.8 111 58.0 156 82.1 201 106.8 246 132.3 112 58.5 157 82.7 202 107.4 247 132.9 113 59.1 158 83.2 203 107.9 248 133.5 114 59.6 159 83.8 204 108.5 249 134.1 115 60.1 160 84.3 205 109.1 250 134.6 116 60.7 161 84.8 206 109.6 251 135.2 117 61.2 162 85.4 207 110.2 252 135.8 118 61.7 163 85.9 208 110.8 253 136.3 119 62.3 164 86.5 209 111.3 254 136.9 120 62.8 165 87.0 210 111.9 255 137.5 121 63.3 166 87.6 211 112.5 256 138.1 122 63.9 167 88.1 212 113.0 257 138.6 123 64.4 168 88.6 213 113.6 258 139.2 124 64.9 169 89.2 214 114.2 259 139.8 125 65.5 170 89.7 215 114.7 260 140.4 126 66.0 171 90.3 216 115.3 261 140.9 127 66.5 172 90.8 217 115.8 262 141.5 128 67.1 173 91.4 218 116.4 263 142.1 129 67.6 174 91.9 219 117.0 264 142.7 130 68.1 175 92.4 220 117.5 265 143.2 131 68.7 176 93.0 221 118.1 266 143.8 132 69.2 177 93.5 222 118.7 267 144.4 133 69.7 178 94.1 223 119.2 268 144.9 134 70.3 179 94.6 224 119.8 269 145.5 102 METHODS OF ANALYSIS [Chap. 41.. Table 4. — Meissl'S Table.— Continued, [Expressed in milligrams.! INVERT INVERT INVERT INVERT COPPEB BOQAR COPPER snoAR COPPER SUGAR COPPER SCOAR 270 146.1 310 169.7 350 193.8 390 218.7 271 146.7 311 170.3 351 194.4 391 219.3 272 147.2 312 170.9 352 195.0 392 219.9 273 147.8 313 171.5 353 195.6 393 220.5 274 148.4 314 172.1 354 196.2 394 221.2 275 149.0 315 172.7 355 196.8 395 221.8 276 149.5 316 173.3 356 197.4 396 222.4 277 150.1 317 173.9 357 198.0 397 223.1 278 150.7 318 174.5 358 198.6 398 223.7 279 151.3 319 175.1 359 199.2 399 224.3 280 151.9 320 175.6 360 199.8 400 224.9 281 152.5 321 176.2 361 ' 200.4 401 225.7 282 153.1 322 176.8 362 201.1 402 226.4 283 153.7 323 177.4 363 201.7 403 227.1 284 154.3 324 178.0 364 202.3 404 227.8 285 154.9 325 178.6 365 203.0 405 228.6 286 155.5 326 179.2 366 203.6 406 229.3 287 156.1 327 179.8 367 204.2 407 230.0 288 156.7 328 180.4 368 204.8 408 230.7 289 157.2 329 181.0 369 205.5 409 231.4 290 157.8 330 181.6 370 206.1 410 232.1 291 158.4 331 182.2 371 206.7 411 232.8 292 159.0 332 182.8 372 207.3 412 233.5 293 159.6 333 183.5 373 208.0 413 234.3 294 160.2 334 184.1 374 208.6 414 235.0 295 160.8 335 184.7 375 209.2 415 235.7 296 161.4 336 185.4 376 209.9 416 236.4 297 162.0 337 186.0 377 210.5 417 237.1 298 162.6 338 l.«6.6 378 211.1 418 237.8 299 163.2 339 187.2 379 211.7 419 238.6 300 163.8 340 187.8 380 212.4 420 239.2 301 161.4 341 188.4 381 213.0 421 239.9 302 165.0 342 189.0 382 213.6 422 240.6 303 165.6 343 189.6 383 214.3 423 241.3 304 166.2 344 190.2 384 214.9 424 242.0 305 166.8 345 190.8 385 215.5 425 242.7 306 167.3 316 191.4 386 216.1 426 243.4 307 167.9 347 192.0 387 216.8 427 244.1 308 168.5 348 192.6 388 217.4 428 244.9 309 169.1 349 193.2 389 218.0 429 430 245.6 246.3 42 MALTOSE. General Gravimetric Method. — Tentative. Proceed as directed under 25 and obtain, from 27, the weight of maltose equivalent to the weight of copper reduced. VIII] FOODS AND FEEDING STUFFS 103 Wein Method. — Tentative. 43 REAGENTS. The reagents and solutions used are described under 24. 44 DETERMINATION. Place 50 cc, of the reagent in a beaker and heat to the boiling point. When boiling briskly, add 25 cc. of the maltose solution containing not more than 0.250 gram of maltose and boil for 4 minutes. Filter immediately through asbestos and determine, by one of the methods given under 26, 29-34 respectively, the amount of copper reduced. Obtain, from 45, the weight of maltose equivalent to the weight of copper found. 45 Table 5. For the determination of maltose. [According to Wein.»] [Expressed in milligrams.) COPPER ccr- PR008 OXID UAh- TOSB COPPER CU- PROUS OXID MAL- TOSE COPPER cv- PROU8 OXID MAL- TOSE COPPER CU- PROUS OXID MAL- TOSE 31 34.9 26.1 71 79.9 61.0 111 125.0 96.4 151 170.0 132.3 32 36.0 27.0 72 81.1 61.8 112 126.1 97.3 152 171.1 133.2 33 37.2 27.9 73 82.2 62.7 113 127.2 98.1 153 172.3 134 I 34 38.3 28.7 74 83.3 63.6 114 128.3 154 173.4 135.0 35 39.4 29.6 75 84.4 64.5 115 129.6 99^9 155 174.5 135.9 38 40.5 30.5 76 85.6 65.4 116 130.6 100.8 156 175.6 136.8 37 41.7 31.3 77 86.7 66.2 117 131 7 101 7 157 176.8 137.7 38 42.8 32.2 78 87.8 67.1 118 132.8 102.6 158 177.9 138.6 39 43.9 33.1 79 88.9 68.0 119 134.0 103.5 159 179 0 1.39.5 40 45.0 33.9 80 90.1 68.9 120 135.1 104.4 160 180.1 140.4 41 46.2 34.8 81 91.2 69 7 121 136.2 105.3 161 181.3 141.3 42 47.3 35.7 82 92.3 70.6 122 137 4 106.2 162 182 4 142.2 43 48.4 36 5 83 93.4 71.5 123 138.5 107.1 163 183.5 143.1 44 49.5 37.4 84 94.6 72.4 124 139.6 108.0 164 184.6 144.0 45 60.7 38.3 85 95.7 73.2 125 140.7 108.9 165 185.8 144.9 49 51.8 39.1 86 96.8 74.1 126 141.9 109 8 166 186.9 145.8 47 52.9 40.0 87 97.9 75.0 127 143.0 110.7 167 188.0 146.7 48 54.0 40.9 88 99.1 75.9 128 144.1 111.6 168 189.1 147 6 49 55.2 41.8 89 100.2 76.8 129 145.2 112.5 169 190.3 148.5 60 66.3 42.6 90 101 3 77.7 130 146.4 113.4 170 191.4 149.4 51 57.4 43.5 91 102 4 78.6 131 147.5 114.3 171 192.5 150.3 52 68.5 44.4 92 103.6 79.5 132 148 6 115 2 172 193 6 151.3 53 59.7 45.2 93 104.7 80.3 133 149.7 116.1 173 194.8 152.0 54 60.8 46.1 94 105.8 81.2 134 150 9 117.0 174 195.9 152.9 55 61.9 47.0 95 107.0 82.1 135 152.0 117.9 175 197.0 153.8 68 63.0 47.8 96 108.1 83.0 136 153 1 118.8 176 198.1 154.7 57 64.2 48.7 97 109.2 83.9 137 154.2 119.7 177 199.3 155.6 68 65.3 49.6 98 110.3 84.8 l.^S 155.4 120.6 178 200.4 156.5 69 66 4 50.4 99 111.5 85.7 139 156.5 121.5 179 201.5 157.4 60 67.6 51.3 100 112.6 86.6 140 157.6 122.4 180 202.6 158.3 61 68.7 52.2 101 113.7 87.5 141 158.7 123.3 181 203 8 159.2 62 69.8 53.1 102 114.8 88.4 142 159.9 124.2 182 204.9 m.\ 63 70.9 53.9 103 116.0 89.2 143 lei.o 125.1 183 20B 0 lfiO.9 64 72.1 54 8 104 117.1 90.1 144 162 1 126.0 184 207.1 161.8 65 73.2 65.7 105 118.2 91.0 145 163.2 126.9 185 208.3 162.7 66 74.3 56.6 106 119 3 91.9 146 164.4 127.8 186 209.4 163 6 67 75.4 67.4 107 120 5 92.8 147 165.5 128.7 187 210 5 164 5 68 76.6 58.3 108 121 6 93.7 148 166.6 129 6 188 211 7 165 4 69 77.7 59.2 109 122.7 94 6 149 167.7 130 5 189 212 8 166 3 70 78.8 60.1 110 123.8 95.5 150 168.9 131.4 190 213.9 167.2 104 45 46 METHODS OF ANALYSIS Table 5. — Continued. For the determination of maltose. [Expressed in milligrams.) [Chap. CU- CU- CU- CU- COPPER PROUS OXID MAL- TOSE COPPER PROUS OXID MAL- TOSE COPPER PROUS OXID MAL- TOSE COPPER PROUS OXID MAL- TOSE 191 215.0 168.1 221 248.7 194.8 251 282.6 221.7 281 316.4 248.7 192 216.2 169.0 222 249,9 195.7 252 283 7 222.6 282 317.5 240.6 193 217.3 169 8 223 251.0 196.6 253 284.8 223.5 283 318.6 250.4 194 218.4 170.7 224 2,52.4 197.5 254 286.0 224.4 284 319.7 251.3 195 219.5 171 6 225 253.3 198.4 255 287.1 225.3 285 320.9 252.2 196 220.7 172.5 226 254.4 199.3 256 288.2 226.2 286 322.0 253.1 197 221.8 173.4 227 255.6 200.2 257 289.3 227 1 287 323.1 2.54.0 198 222.9 174.3 228 256.7 201.1 258 290.5 228 0 288 324.2 254.9 199 224.0 175.2 229 257.8 202 0 259 291 6 228.9 289 325.4 255.8 200 225.2 176.1 230 258.9 202.9 260 292.7 229.8 290 326.5 256.6 201 226.3 177.0 231 260.1 203.8 261 293.8 230.7 291 327.4 257.5 202 227.4 177.9 232 261 2 204.7 262 295.0 231.6 292 328,7 2.58.4 203 228.5 178.7 233 262.3 205.6 263 296.1 232.5 293 329.9 259.3 204 229.7 179.6 234 263.4 206.5 264 297.2 2.33.4 294 331.0 260.2 205 230.8 180.5 235 264.6 207.4 265 298.3 234.3 295 332.1 261.1 206 231.9 181.4 236 265.7 208.3 266 299 5 235.2 296 333.2 262.0 207 233.0 182.3 237 266 8 209 1 267 300.6 236.1 297 334.4 262.8 208 234.2 183.2 238 268.0 210 0 268 301.7 2.37 0 298 335.5 263.7 209 235.3 184.1 239 269.1 210.9 269 302 8 237.9 299 336.6 264.6 210 236.4 185.0 240 270.2 211.8 270 304.0 238.8 300 337.8 265.5 211 237.6 185.9 241 271.3 212.7 271 305,1 239,7 212 238.7 186.8 242 272.5 213 6 272 306.2 240.6 213 239.8 187.7 243 273 6 214.5 273 307.3 241.5 214 240.9 188.6 244 274.7 215.4 274 308.5 242.4 215 242.1 189.5 245 275.8 216.3 275 309.6 243.3 216 243.2 190.4 246 277.0 217.2 276 310.7 244 2 217 244.3 191.2 247 278.1 218 1 277 311.9 245.1 218 245,4 192.1 248 279.2 219.0 278 313 0 246.0 219 246.6 193.0 249 280.3 219.9 279 314.1 246.9 220 247.7 193.9 250 281.5 220.8 280 315.2 247.8 LACTOSE. General Gravimetric Method. — Tentative. Proceed as directed under 25 and obtain, from 27, the weight of lactose equivalent to the weight of copper reduced. Soxhlet-Wein Method. — Official. 47 REAGENTS. The reagents and solutions used are described under 24. 48 DETERMINATION. Place 50 cc. of the reagent in a beaker and heat to the boiling point. When boiling briskly, add 100 cc. of the lactose solution containing not more than 0.300 gram of lactose and boil for 6 minutes. Filter immediately through asbestos and determine by one of the methods given under 26, 29-34 inclusive, the amount of copper reduced. Obtain, from 49, the weight of lactose equivalent to the weight of copper found. vni] 49 FOODS AND FEEDING STUFFS Table 6. For the determination of lactose (Soxhlei-Wein^). [Expressed in milligrams. ) 105 COPPER LACTOSE COPPER LACTOSE COPPER LACTOSE COPPER LACTOSE COPPER LACTOSE 100 71.6 160 116.4 220 161.9 280 208.3 340 255.7 101 72.4 161 117.1 221 162.7 281 209.1 341 256.5 102 73.1 162 117.9 222 163.4 282 209.9 342 257.4 103 73.8 163 118.6 223 164.2 283 210.7 343 2.58.2 104 74.6 164 119.4 224 164.9 284 211.5 344 259.0 105 75.3 165 120.2 225 165.7 285 212.3 345 259.8 106 76.1 186 120.9 226 166.4 286 213.1 346 260.6 107 76.8 167 121.7 227 167.2 287 213.9 347 261.4 108 77.6 168 122.4 228 167.9 288 214.7 348 262.3 109 78.3 169 123.2 229 168.6 289 215.5 349 263.1 110 79.0 170 123.9 230 169.4 290 216.3 350 263.9 111 79.8 171 124.7 231 170.1 291 217.1 351 264.7 112 80.5 172 125.5 232 170.9 292 217.9 352 265.5 113 81 3 173 126.2 233 171.6 293 218.7 353 266.3 114 82.0 174 127.0 234 172.4 294 219.5 354 267.2 115 82.7 175 127.8 235 173.1 295 220.3 355 268.0 116 83 5 176 128.5 236 173.9 296 221.1 356 268.8 117 84.2 177 129.3 237 174.6 297 221.9 357 269.6 118 85.0 178 130.1 238 175 4 298 222.7 358 270.4 119 85.7 179 130.8 239 176.2 299 223.5 359 271.2 120 86.4 180 131.6 240 176.9 300 224.4 360 272.1 121 87.2 181 132.4 241 177.7 301 225.2 361 272.9 122 87.9 182 133.1 242 178.5 302 225 9 362 273.7 123 88.7 183 133.9 243 179.3 303 226.7 363 274.5 124 89.4 184 134.7 244 180.1 304 227.5 304 275.3 125 90.1 185 135.4 245 180.8 305 228.3 365 276.2 120 90.9 186 136.2 246 181.6 306 229.1 366 277.1 127 91.6 187 137.0 247 182.4 307 229 8 367 277.9 128 92.4 188 137.7 248 183.2 308 230.6 278.8 129 93.1 189 138.5 249 184.0 309 231.4 369 279.6 130 93.8 190 1.39.3 250 184.8 310 232.2 370 280.5 131 94.6 191 140.0 251 185.5 311 232 9 371 281.4 132 95.3 192 140.8 252 186.3 312 233.7 372 282.2 133 96.1 193 141.6 253 187.1 313 234.5 373 283.1 134 96.9 194 142.3 254 187.9 314 235.3 374 283.9 135 97.6 195 143.1 255 188.7 315 236.1 375 284.8 136 98.3 196 143.9 256 189.4 316 2.36.8 376 285.7 137 99 1 197 144.6 257 190.2 317 2,37.6 377 286.5 138 99.8 198 145.4 258 191.0 318 2.38.4 378 287.4 139 100.5 199 146.2 259 191.8 319 239.2 379 288.2 140 101.3 200 146.9 260 192.5 320 240 0 380 289.1 141 102.0 201 147.7 261 193.3 321 240.7 381 289.9 142 102.8 202 148.5 262 194.1 322 241.5 382 290.8 143 103.5 203 149.2 263 194.9 323 242.3 383 291.7 144 104.3 204 150.0 264 195.7 324 243.1 384 292.5 145 105.1 205 150.7 265 196.4 325 243.9 385 293.4 146 105.8 206 151.5 266 197 2 326 244.6 386 294.2 147 106.0 207 152.2 267 198.0 327 245.4 387 295.1 148 107.3 208 153.0 268 198.8 328 246.2 388 296.0 149 lOS.l 209 153.7 269 199.5 329 247.0 389 296.8 150 10S.8 210 154.5 270 200.3 330 247.7 390 297.7 151 109.6 211 155.2 271 201.1 331 248.5 391 298.5 152 110.3 212 1.56.0 272 201.9 332 249.2 392 299.4 153 111 1 213 1.56.7 273 202.7 333 250.0 393 300.3 154 111.9 214 157.5 274 203.5 334 250.8 394 301.1 155 112.6 215 15S.2 275 204.3 335 251.6 395 302.0 156 113 4 216 159 0 276 205.1 336 252 5 396 302.8 157 114.1 217 159.7 277 205.9 337 253.3 397 303.7 158 114.9 218 160.4 278 206.7 338 254.1 398 304.6 159 115.6 219 161.2 279 207.5 I 339 254.9 399 400 305.4 306.3 106 METHODS OF ANALYSIS [Chap. DEXTROSE. 50 Approximate Volumetric Method for Rapid Work. — Tentative. Proceed as directed under 21 . Standardize the reagent against pure dextrose. 51 Soxhlet Method.— Tentative. Proceed as directed under 23. Under these conditions 100 cc. of the reagent require 0.475 gram of anhydrous dextrose for complete reduction and the formula 100 X 0.475 . r ^ . becomes ; = per cent of dextrose. VW 52 General Gravimetric Method. — Tentative. Proceed as directed under 25 and obtain, from 27, the weight of dextrose equiv- alent to the weight of copper reduced. Allihn Gravimetric Method. — Tentative. 53 REAGENT. Allihn' s Modification of Fehling's Solution. — Prepare by mixing, immediately before use, equal volumes of (a) and (b). (a) Copper sulphate solution. — Dissolve 34.639 grams of copper sulphate (CuS045H,0) in water and dilute to 500 cc. (b) Alkaline tartrate soZuh'on.— Dissolve 173 grams of Rochelle salts and 125 grams of potassium hydroxid in water and dilute to 500 cc. 54 DETERMINATION. Place 30 cc. of the copper sulphate solution, 30 cc. of the alkaline tartrate solu- tion, and 60 cc. of water in a beaker and heat to boiling. Add 25 cc. of the solution of the material to be examined, prepared so as not to contain more than 0.25 gram of dextrose, and boil for exactly 2 minutes, keeping the beaker covered. Filter immediately through asbestos, and obtain the weight of copper by one of the methods given under 26, 29-34 inclusive. The corresponding weight of dextrose is found in 55. vm] 55 FOODS AND FEEDING STUFFS Table 7.— Allihn-s Table. i" For the determination of dextrose. (Expressed in milligrams.) 107 COPPER cu- PRons OXID DEX- TROSE COPPER cu- 1 Roua O -ID DEX- TROSE COPPER CU- PROUS OXID DEX- TROSE COPPER CU- PROUS OXID DEX- TROSE 11 12.4 6.6 71 79.9 36.3 131 147.5 66.7 191 215.0 97.8 12 13.5 7.1 72 81.1 36.8 132 148.6 67.2 192 216.2 98.4 13 14.6 7.6 73 82.2 37.3 133 149.7 67.7 193 217.3 98.9 14 15.8 8,1 74 83.3 37.8 134 150.9 68 2 194 218.4 99.4 15 16.9 8.8 75 84.4 38.3 135 152.0 68.8 195 219.5 100.0 16 18.0 9.0 76 85.6 38.8 136 153.1 69.3 196 220.7 100.5 17 19.1 9.5 77 86.7 39.3 137 154,2 69.8 197 221.8 101.0 18 20.3 10.0 78 87.8 39.8 138 155.4 70.3 198 222.9 101.5 19 21.4 10.5 79 88.9 40.3 139 156.5 70.8 199 224.0 102.0 20 22.5 11.0 80 90.1 40.8 140 157.6 71.3 200 225.2 102.9 21 23.6 11.5 81 91.2 41.3 141 158.7 71.8 201 226.3 103.1 22 24.8 12.0 82 92.3 41.8 142 159.9 72 3 202 227.4 103.7 23 25.9 12.5 83 93.4 42.3 143 161.0 72.9 203 228.5 104.2 24 27.0 13.0 84 94.6 42.8 144 162.1 73.4 204 229.7 104.7 25 28.1 13.5 85 95.7 43.4 145 163.2 73.9 205 230.8 105.3 26 29.3 14.0 86 96.8 43.9 146 164.4 74.4 206 231.9 105.8 27 30.4 14.5 87 97.9 44.4 147 165.5 74.9 207 233.0 108.3 28 31.5 15.0 88 99.1 44.9 148 166.6 75.5 208 234.2 106.8 29 32.7 15.5 89 100.2 45.4 149 167.7 76.0 209 235.3 107.4 30 33.8 16.0 90 101 3 45.9 150 168.9 76.5 210 236.4 107.9 31 34.9 16.5 91 102.4 46.4 151 170.0 77.0 211 237.6 108.4 32 36.0 17.0 92 103.6 46.9 152 171.1 77.5 212 238.7 109.0 33 37.2 17.5 93 104.7 47.4 153 172.3 78.1 213 239 8 109.5 34 38.3 18.0 94 105.8 47.9 154 173.4 78.6 214 240.9 110 0 35 39.4 18.5 95 107.0 48.4 155 174.5 79.1 215 242.1 110. « 36 40 5 18.9 96 108.1 48.9 156 175.6 79.6 216 243.2 111.1 37 41.7 19.4 97 109.2 49.4 157 176.8 80.1 217 244.3 111.8 38 42.8 19.9 98 110.3 49.9 158 177.9 80.7 218 245.4 112.1 39 43.9 20.4 99 111.5 50.4 159 179.0 81.2 219 246.6 112.7 40 45.0 20.9 100 112.6 50.9 160 180.1 81.7 220 247.7 113.2 41 46.2 21.4 101 113.7 51.4 161 181.3 82.2 221 248.7 113.7 42 47.3 21.9 102 114.8 51.9 162 182.4 82.7 222 249.9 114.3 43 48 4 22.4 103 116.0 52.4 163 183.5 83,3 223 251.0 114.8 44 49.5 22.9 104 117.1 52.9 164 184.6 83.8 224 252.4 115.3 45 50.7 23.4 105 118.2 53.5 165 185.8 84.3 225 253.3 115.9 46 51.8 23.9 106 119.3 54.0 166 186.9 84.8 226 254.4 116.4 47 52.9 24.4 107 120.5 54.5 167 188.0 85.3 227 255.6 116.9 48 54 0 24.9 108 121.6 55.0 168 189.1 85.9 228 256.7 117.4 49 55.2 25.4 109 122.7 55.5 169 190.3 86.4 229 257.8 118.0 60 56.3 25.9 110 123.8 56.0 170 191.4 86.9 230 258.9 118.5 51 57.4 26.4 111 125.0 56.5 171 192.5 87.4 231 260.1 119.0 52 58.5 26.9 112 126.1 57.0 172 193.6 87.9 232 261.2 119.6 53 59.7 27.4 113 127.2 57.5 173 194.8 88.5 233 262.3 120.1 54 60.8 27.9 114 128.3 58.0 174 195.9 89.0 234 263.4 120.7 55 61.9 28.4 115 129.6 58.6 175 197.0 89.5 235 264.6 121.2 56 63.0 28.8 116 130 6 59.1 176 198.1 90.0 236 265.7 121.7 57 64.2 29.3 117 131.7 59.6 177 199.3 90.5 237 266.8 122.3 58 65.3 29.8 118 132.8 60.1 178 200.4 91.1 238 268.0 122.8 59 66.4 30.3 119 134.0 60.6 179 201.5 91.6 239 269.1 123.4 60 67.6 10.8 120 135.1 61.1 180 202.6 92.1 240 270.2 123.0 fil 68.7 31.3 121 136.2 61.6 181 203.8 92.6 241 271.3 124.4 62 69.8 31.8 122 137.4 62.1 182 204.9 93.1 242 272.5 125.0 63 70.9 32.3 123 1.38.5 62.6 183 206.0 93.7 243 273.6 125.6 64 72.1 32.8 124 139.6 63 1 184 207.1 94.2 244 274.7 129.0 65 73.2 33.3 125 140.7 63.7 185 208.3 94.7 245 275.8 129. S 66 74.3 33.8 126 141 9 64.2 186 209.4 95.2 246 277.0 127.1 67 75.4 34.3 127 143.0 64.7 187 210.5 95.7 247 278.1 127.9 6S 76.6 34.8 128 144 1 65.2 188 211.7 96.3 248 279.2 128.1 69 77.7 35.3 129 145.2 65.7 189 212.8 96.8 249 280.3 128 7 70 78.8 35.8 130 146.4 66.2 190 213.9 97.3 250 281.5 129.2 108 55 METHODS OF ANALYSIS Table 7.— Allihns Table. — Continued. [Expressed in milligrams.] [Chap. co- cn- CU- CU- COPPER pnons OXID DEX- TROSE COPPER PRODS OXID DEX- TROSE COPPER PROUS OXID DEX- TROSE COPPER PROUS OXID DEX- TROSE 251 282.6 129.7 306 344.5 159.8 361 406.4 190.6 416 468.4 222,2 252 283.7 130.3 307 345.6 160.4 362 407 6 191.1 417 469,5 222,8 253 284.8 130.8 308 346.8 160.9 363 408.7 191.7 418 470,6 223 3 254 286.0 131.4 309 347.9 161.5 364 409 8 192.3 419 471 8 223 9 255 287.1 131.9 310 349.0 162.0 410.9 192 9 420 472,9 224.5 256 288.2 132.4 311 3.50 1 162.6 366 412 1 193.4 421 474,0 225,1 257 289.3 133 0 312 351.3 163 1 367 413.2 194.0 422 475 6 225 7 258 290 5 133.5 313 352.4 163.7 368 414 3 194.6 423 476 2 226 3 259 291.6 134.1 314 353.5 164.2 369 415.4 195.1 424 477 4 226,9 260 292.7 134.6 315 354.6 164.8 370 416 6 195.7 425 478.5 227.5 261 293.8 135.1 316 355.8 165.3 371 417 7 196 3 426 479 6 228.0 262 295.0 135.7 317 356.9 165 9 372 418. S 196.8 427 480,7 228.6 263 296.1 1.36.2 318 3.58.0 166.4 373 420.0 197.4 428 481 9 229,2 264 297.2 136.8 319 359 1 167.0 374 421.1 198.0 429 483,0 229 8 265 298.3 137.3 320 360.3 167.5 375 422.2 198.6 430 484.1 230.4 266 299.5 137.8 321 361 4 168.1 376 423.3 199.1 431 485 3 231,0 267 300.6 138.4 322 362.5 168.6 377 424 5 199,7 432 486 4 231,6 268 301.7 1.38 9 323 363.7 169.2 378 425 6 200 3 433 487,5 232,2 269 302.8 139.5 324 364.8 169 7 379 426.7 200.8 434 488,6 232.8 270 304.0 140.0 325 365.9 170.3 380 427.8 201.4 435 489.7 233.4 271 305,1 140.6 326 367.0 170 3 381 429 0 202.0 436 490,9 233.9 272 306.2 141.1 327 368.2 171.4 382 4.30 1 202 5 437 492,0 2.34.5 273 307.3 141.7 328 369.3 172.0 383 431.2 203.1 438 493,1 2.35.1 274 308.5 142 2 329 370.4 172 5 384 432.3 203,7 439 494,3 235.7 275 309.6 142.8 330 371.5 173.1 385 433.5 204.3 440 495,4 236.3 ■276 310.7 143.3 331 372.7 173.7 386 434.6 204.8 441 496.5 236.9 277 143.9 332 373.8 174.2 387 435.7 205,4 442 497.6 237 5 278 313:0 144.4 333 374.9 174.8 388 4.36.8 206,0 443 498 8 238 1 279 314.1 145.0 334 376.0 175.3 438.0 205 5 444 499,9 238,7 .280 315.2 145.5 335 377.2 175.9 390 439.1 207.1 445 501.0 239.3 281 316.4 146.1 336 378.3 176.5 391 440.2 207,7 446 502,1 239.8 282 317.5 146.6 337 379.4 177.0 392 441.3 208,3 447 503,2 240.4 283 318.6 147.2 338 380.5 177.6 393 442.4 208,8 448 504,4 241 0 284 319 7 147.7 339 381.7 178.1 394 443.6 209,4 449 505,5 241.6 285 320.9 148.3 340 382.8 178.7 395 444.7 210 0 450 506 6 242.2 286 322.0 148.8 341 383.9 179.3 396 445.9 210,6 451 507.8 242.8 287 323 1 149 4 342 385.0 179.8 397 447.0 211.2 452 508,9 243.4 288 324.2 149.9 343 386.2 180 4 398 448.1 211 7 453 510,0 244.0 289 325.4 150.5 344 387.3 180.9 449 2 212,3 454 511,1 244,6 290 326.5 151.0 345 388.4 181.5 400 450 3 212,9 455 512.3 245.2 291 327.4 151.6 346 389.6 182.1 401 451.5 213,5 456 513.4 245.7 292 328 7 152.1 347 390.7 182.6 402 452.6 214.1 457 511,5 246.3 293 329.9 152.7 348 391.8 183.2 403 453.7 214,6 458 515 6 246.9 294 331.0 l.')3.2 349 392 9 183.7 404 454.8 215.2 459 516 8 247.5 295 332.1 153.8 350 394.0 184.3 405 456.0 215.8 460 517,9 248.1 296 333.3 154.3 351 395.2 184.9 406 457.1 216,4 461 519,0 248,7 297 334.4 154 9 352 396.3 185.4 407 458.2 217,0 462 520 1 249,3 298 3.35.5 1.55.4 353 397.4 186.0 408 459.4 217.5 463 521.3 249.9 299 3.36.6 1.56.0 354 398 6 186 6 409 460.5 218 1 300 337.8 156.5 355 399.7 187.2 410 461.6 218,7 301 3.38.9 157.1 356 400.8 187.7 411 462.7 219 3 302 340 0 1.57.6 357 401 9 188.3 412 463.8 219 9 303 341.1 158 2 358 403 1 188 9 413 465.0 220 4 304 342 3 158 7 359 401.2 189.4 414 466.1 221.0 305 343 4 1.59 3 360 405 3' 191 0 415 467 2 221,6 Vm] FOODS Al^ro FEEDING STUFFS 109 56 REDUCING SUGARS OTHER THAN DEXTROSE. Proceed as directed under 54 and multiply the weight of dextrose found in 55 by the following factors: Levulose, 1.093; Invert sugar, 1.046; Arabinose, 0.969; Xylose, 1.017; Galactose, 1.114. Total Sugars." (Applicable to cattle foods.) 57 preparation of solution. Place 12 grams of the material in a 300 cc. graduated flask, if the substance has an acid reaction add 1-3 grams of calcium carbonate, and boil on a steam bath fori hour with 150 cc. of 50% alcohol by volume, using a small funnel in the neck of the flask to condense the vapor. Cool, and allow the mixture to stand several hours, prefer- ably overnight. Make up to volume with neutral 95% alcohol, mix thoroughly, allow to settle, transfer 200 cc. to a beaker with a pipette, and evaporate on a steam bath to a volume of 20-30 cc. Do not evaporate to dryness, a little alcohol in the residue doing no harm. Trans- fer to a 100 cc. graduated flask, and rinse the beaker thoroughly with water, adding the rinsings to the contents of the flask. Add enough saturated neutral lead acetate solution to produce a flocculent precipitate, shake thoroughly and allow to stand 15 minutes. Make up to the mark with water, mix thorough'y, and filter through a dry filter. Add sufficient anhydrous sodium carbonate to the filtrate to precipitate all the lead, again filter through a dry paper and test the filtrate with a little anhy- drous sodium carbonate to make sure that all the lead has been removed. 58 determination of REDUCING SUGARS. Proceed as directed under 26 or 29-34 respectively, employing the Soxhlet modificatiin of Fehling's solution and using 25 cc. of the solution (representing 2 grams of the sample), prepared as directed in 57. Express the results as dextrose or invert sugar. 59 SUCROSE. Introduce 50 cc. of the solution, prepared as directed in 57, into a 100 cc. gradu- ated flask, add a piece of litmus paper, neutralize with acetic acid, add 5 cc. of con- centrated hydrochloric acid and allow the inversion to proceed at room temperature as directed under 14 or 16. When inversi m is complete, transfer the solution to a beaker, neutralize with sodium carbonate, return the solution to ih^ 100 cc. flask, dilute to the mark with water, filter if necessary and determine reducing sugars in 50 cc. of the solution (representing 2 grams of the sample) as directed in 58, and calculate the results as invert sugar. Subtract the per cent of reducing sugars be- fore inversion from the per cent of total sugar after inversion, both calculated as invert sugar, and multiply the difference by 0.95 to obtain the per cent of sucrose present. Since the insoluble material of grain or cattle food occupies some space in the flask as originally made up, it is necessary to correct for this volume. Results of a large number of determinations on various materials have shown the average volume of 12 grams of material to be 9 cc, and therefore to obtain the true amount of sugars present all results must be multiplied by the factor 0.97. 110 METHODS OF ANALYSIS [Chap. 60 Direct Acid Hydrolysis (Modified Sachsse Method). — Official. (In this method there will be included as starch the pentosans and other carbo- hydrate bodies present which undergo hydrolysis and conversion into reducing sugars on boiling with hydrochloric acid.) Stir a quantity of the sample, representing 2.5-3 grams of the dry material, in a beaker with 50 cc. of cold water for an hour. Transfer to a filter and wash with 250 cc. of cold water. Heat the insoluble residue for 2^ hours with 200 cc. of water and 20 cc. of hydrochloric acid (sp. gr. 1.125) in a flask provided with a reflux con- denser. Cool, and nearly neutralize with sodium hydroxid. Complete the volume to 250 cc, filter, and determine the dextrose in an aliquot of the filtrate as directed under 52 or 54. The weight of the dextrose obtained multiplied by 0.90 gives the weight of starch. The factor 0.9 is the theoretical ratio between starch and glucose but, according to Noyes" and other investigators, the factor 0.93 more nearly approaches the actual yield. Diastase Method with Subsequent Acid Hydrolysis. — Tentative. 61 REAGENT. Malt extract. — Digest 10 grams of fresh, finely ground malt for 2-3 hours at or- dinary temperature with 200 cc. of water and filter. Determine the amount of dex- trose in a given quantity of the filtrate after boiling with acid, etc., as in the starch determination, and make the proper correction in the subsequent determination. 62 DETERMINATION. Extract a convenient quantity of the substance (ground to an impalpable powder and representing 4-5 grams of the dry material) on a hardened filterwith 5 successive portions of 10 cc. of ether ; wash with 150 cc. of 10% alcohol and then with a little strong alcohol. Place the residue in a beaker with 50 cc. of water, immerse the beaker in boil- ing water, and stir constantly for 15 minutes or until all the starch is gelatinized ; cool to55°C., add 20 cc. of malt extract, and maintain at this temperature for an hour. Heat again to boiling for a few minutes, cool to55''C., add 20 cc. of malt extract, and maintain at this temperature for an hour or until the residue treated with iodin shows no blue color upon microscopic examination. Cool, make up directly to 250 cc, and filter. Place 200 cc. of the filtrate in a flask with 20 cc. of hydrochloric acid (sp. gr. 1.125) ; connect with a reflux condenser and heat in a boiling water bath for 2^ hours. Cool, nearly neutralize with sodium hydroxid solution, finish the neutralization with sodium carbonate solution, and make up to 500 cc. Mix the solution well, pour through a dry filter, and determine the dextrose in an aliquot as directed under 52 or 54. Conduct a blank determination upon the same volume of the malt extract as used upon the sample and correct the weight of reduced copper accord- ingly. The weight of the dextrose obtained multiplied by 0.90 gives the weight of starch. PENTOSANS.— TENTATIVE. 63 REAGENT. Phloroglucin. — Dissolve a small quantity of the phloroglucin in a few drops of acetic anhydrid, heat almost to boiling, and add a few drops of concentrated sul- VIII] FOODS AND FEEDING STUFFS 111 phuric acid. A violet color indicates the presence of diresorcin. A phloroglucin which gives more than a faint coloration may be purified by the following method: Heat in a beaker about 300 cc. of hyd ochloric acid (sp. gr. 1.06) and 11 grams of commercial phloroglucin, added in small quantities at a time, stirring constantly until it has almost entirely dissolved. Pour the hot solution into a sufficient quan- tity of the same hydrochloric acid (cold) to make the volume 1500 cc. Allow it to stand at least overnight, preferably several days, to permit the diresorcin to crystallize out. Filter immediately before using. A yellow tint does not inter- fere with its usefulness. In using it, add the volume containing the required amount to the distillate. 64 DETERMINATION. Place a quantity of the material, 2-5 grams, chosen so that the weight of phloro- glucid obtained shall not exceed 0.300 gram, in a 300 cc. distillation flask, together with 100 cc. of 12% hydrochloric acid (sp. gr. 1.06), and several pieces of recently heated pumice stone. Place the flask on a wire gauze, connect with a condenser, and heat, rather gently at first, and regulate so as to distil over 30 cc. in about 10 minutes, the distillate passing through a small filter paper. Rep'ace the 30 cc. distilled by a like quantity of the dilute acid, added by means of a separatory funnel in such a manner as to wash down the particles adhering to the sides of the flask, and continue the process until the distillate amounts to 360 cc. To the total distillate add gradually a quantity of phloroglucin dissolved in 12% hydrochloric acid and stir thoroughly the resulting mixture. The amount of phloroglucin used should be about double that of the furfural expected. The solution turns first yellow, then green, and very soon an amorphous greenish precipitate appears, which grows darker rapidly, till it becomes finally almost black. Make the solution up to 400 cc. with 12% hydrochloric acid, and allow to stand overnight. Filter the amorphous black precipitate into a tared Gooch crucible through an asbestos mat, wash carefully with 150 cc. of water in such a way that the water is not entirely removed from the crucible until the very last, then dry for 4 hours at the temperature of boiling water, cool and weigh in a weighing bottle, the increase in weight being reckoned as furfural phloroglucid. To calculate the furfural, pen- tose, or pentosan from the phloroglucid, use the following formulas given by Krober: (1) For a weight of phloroglucid, designated by "a" in the following formulas, under 0.03 gram, Furfural = (a + 0.0052) X 0.5170. Pentoses = (a + 0.0052) X 1.0170. Pentosans = (a + 0.0052) X 0.8949. In the above and also in the following formulas, the factor 0.0052 represents the weight of phloroglucid which remains dissolved in the 400 cc. of acid solution. (2) For a weight of phloroglucid "a" over 0.300 gram. Furfural = (a + 0.0052) X 0.5180. Pentoses = (a + 0.0052) X 1.0026. Pentosans = (a + 0.0052) X 0.8824. For a weight of phloroglucid "a" between 0.03 and 0.300 gram use Krober's table, 65, or the following formulas in which the factors were calculated from Krober's tables by C. A. Browne, i' Furfural = (a + 0.0052) X 0.5185. Pentoses = (a + 0.0052) X 1.0075. Pentosans = (a + 0.0052) X 0.8866. 112 65 methods of analysis Table 8.— Krober's Table." For Determining Pentoses and Pentosans. [Expressed in grams.] [Chap. rORFtlRAL PHLOROGLUCID FURFURAL \RABINOSE ARABAN XYLOSE XYLAN PENTOSE PENTOSAN 0.030 0.0182 0.0391 0.0344 0.0324 0.0285 0.0358 0.0315 0.031 0.0188 0.0402 0.0354 0.0333 0.0293 0.0368 0 0324 0.032 0.0103 0.0413 0.0363 0.0342 0.0301 0.0378 0.0333 0.033 0.0198 0.0424 0.0373 0.0352 0.0309 0.0388 0.0341 0.034 0.0203 0.0435 0.0383 0.0361 0.0317 0.0398 0.0350 0.035 0.0209 0.0446 0.0393 0.0370 0.0326 0.0408 0.0359 0.036 0.0214 0.0457 0.0402 0.0379 0.0334 0.0418 0.0368 0.037 0.0219 0.0468 0.0412 0.0388 0.0342 0.0428 0.0377 0.038 0.0224 0.0479 0.0422 0.0398 0.0350 0.0439 0.0386 0.039 0.0229 0 .0490 0.0431 0.0407 0.0358 0.0449 0.0395 0.040 0.0235 0.0501 0.0441 0.0416 0.0366 0.0459 0.0404 0.041 0.0240 0.0512 0.0451 0.0425 0.0374 0.0469 0.0413 0.042 0.0245 0.0523 0.0460 0.0434 0.0382 0.0479 0.0422 0.043 0.0250 0.0534 0.0470 0.0443 0.0390 0.0489 0.0431 0.044 0.0255 0.0545 0.0480 0.0452 0.0398 0.0499 0.0440 0.045 0.0260 0.0556 0.0490 0.0462 0.0406 0.0509 0.0448 0.046 0.0266 0.0567 0.0499 0.0471 0.0414 0.0519 0.0457 0.047 0.0271 0.0578 0.0509 0.0480 0.0422 0.0529 0.0466 0.048 0.0276 0.0589 0.0519 0.0489 0.0430 0.0539 0.0475 0.049 0 .0281 0.0600 0.0528 0.0498 0.0438 0.0549 0.0484 0.050 0.0286 0.0611 0.0538 0.0507 0.0446 0.0559 0.0492 0.051 0.0292 0.0622 0.0548 0.0516 0.0454 0.0569 0.0501 0.052 0.0297 0.0633 0.0557 0.0525 0.0462 0.0579 0.0510 0.053 0.0302 0.0644 0.0567 0.0534 0.0470 0.0589 0.0519 0.054 0.0307 0.0655 0.0576 0.0543 0.0478 0.0599 0.0528 0.055 0.0312 0.0666 0.0586 0.0553 0.0486 0.0610 0.0537 0.056 0.0318 0.0677 0.0596 0.0562 0.0494 0.0620 0.0546 0.057 0.0323 0.0688 0.0605 0.0571 0.0502 0.0630 0.0555 0.058 0.0328 0.0699 0.0615 0.0580 0 0510 0.0640 0.0564 0.059 0.0333 0.0710 0.0624 0.0589 0.0518 0.0650 0.0573 0.060 0.0338 0.0721 0.0634 0.0598 0.0526 0.0660 0.0581 0.061 0.0344 0.0732 0.0644 0.0607 0.0534 0.0670 0.0590 0.062 0.0349 0.0743 0.0653 0.0616 0.0542 0.0680 0.0599 0.063 0.0354 0.0754 0.0663 0.0626 0.0550 0.0690 0.0608 0.064 0.0359 0.0765 0.0673 0.0635 0.0558 0.0700 0.0617 0.065 0.0364 0.0776 0.0683 0.0644 0.0567 0.0710 0.0625 0.066 0.0370 0.0787 0.0692 0.0653 0.0575 0.0720 0.0634 0.067 0.0375 0.0798 0.0702 0.0662 0.0583 0.0730 0.0643 0.068 0.0380 0.0809 0.0712 0.0672 0.0591 0.0741 0.0652 0.069 0.0385 0.0820 0.0721 0.0681 0.0599 0.0751 0.0661 0.070 0.0390 0.0831 0.0731 0.0690 0.0607 0.0761 0.0670 0.071 0.0396 0.0842 0.0741 0.0699 0.0615 0.0771 0.0679 0.072 0.0401 0.0S53 0.0750 0.0708 0 0623 0.0781 0.0688 0.073 0.0406 0.0864 0.0760 0.0717 0.0631 0.0791 0.0697 0.O74 0.0411 0.0875 0.0770 0.0726 0.0639 0.0801 0.0706 VIII] 65 FOODS AND FEEDING STUFFS Table 8.— Krober's Table.— Continued. (Expressed in grams | 113 lURFURAI, FURFURAL AR.AllINOSE AR.^DAN XYLOSE XYLAN PENTOSE PENTOSAN PHLOROQIUCID 0.075 0.0416 0.0886 0.0780 0.0736 0.0647 0.0811 0.0714 0.076 0.0422 0.0S97 0.0780 0.0745 0.0655 0.0821 0.0722 0.077 0.0427 0.0908 0.0799 0.0754 0.0G63 0.0831 0.0731 0.078 0.0432 0.0019 0.0809 0.0763 0.0671 0.0841 0.0740 0.079 0.0437 0.0930 0.0818 0.0772 0.0679 0.0851 0.0749 0.080 0.0442 0.0941 0.0828 0.0781 0.0687 0.0861 0.0758 0.081 0.0448 0.0952 0.0838 0.0790 0.0695 0.0871 0.0767 0.082 0.0453 0.0063 0.0847 0.0799 0.0703 0.0881 0.0776 0.083 0.0458 0.0974 0.0857 0.0808 0.0711 0.0891 0.0785 0.084 0.0463 0.0985 0.0867 0.0817 0.0719 0.0901 0.0794 0.085 0.0468 0.0996 0.0877 0.0827 0.0727 0.0912 0.0803 0.086 0.0474 0.1007 0.0886 0.0836 0.0735 0.0922 0.0812 0.087 0.0479 0.1018 0.0896 0.0845 0.0743 0.0932 0.0821 0.088 0.0484 0.1029 0.0906 0.0854 0.0751 0.0942 0.0830 0.089 0.0489 0.1040 0.0915 0.0863 0.0759 0.0952 0.0838 0.090 0.0494 0.1051 0.0925 0.0872 0.0767 0.0962 0.0847 0.091 0.0499 0.ir62 0.0935 0.0881 0.0775 0.0972 0.0856 0.092 0.0505 0.1073 0.0944 0.0890 0.0783 0.0982 0.0865 0.093 0.0510 0.1P84 0.0954 0.0900 0.0791 0.0992 0.0874 0.094 0.0515 0.1095 0.0964 0.0909 0.0800 0.1002 0.0883 0.095 0.0520 0.1106 0.0974 0.0918 0.0808 0.1012 0.0891 0.096 0.0525 0.1117 0.0983 0.0927 0.0816 0.1022 0.0899 0.097 0.0531 0.1128 0.0993 0.0936 0.0824 0.1032 0.0908 0.098 0.0536 0.1139 0.1003 0.0946 0.0832 0.1043 0.0917 0.099 0.0541 0.1150 0.1012 0.0955 0.0840 0.1053 0.0926 0.100 0.0546 0.1161 0.1022 0.0964 0.0848 0.1063 0.0935 0.101 0.0551 0.1171 0.1032 0.0973 0.0856 0.1073 0.0944 0.102 0.0557 0.1182 0.1041 0.0982 0.0864 0.1083 0.0953 0.103 0.0562 0.1193 0.1051 0.0991 0.0872 0.1093 0.0962 0.104 0.0567 0.1204 0.1060 0.1000 0.0880 0.1103 0.0971 0.105 0.0572 0.1215 0.1070 0.1010 0.0888 0.1113 0.0979 0.106 0.0577 0.1226 0.1080 0.1019 0.0896 0.1123 0.0988 0.107 0.0582 0.1237 0.1089 0.1028 0.0904 0.1133 0.0997 0.108 0.0588 0.1248 0.1099 0.1037 0.0912 0.1143 0.1006 0.109 0.0593 0.1259 0.1108 0.1046 0.0920 0.1153 0.1015 0.110 0.0598 0.1270 0.1118 0.1055 0.0028 0.1163 0.1023 0.111 0.0603 0.1281 0.1128 0.1064 0.0936 0.1173 0.1032 0.112 0.0608 0.1292 0.1137 0.1073 0.0944 0.11S3 0.1041 0.113 0.0614 0.1303 0.1147 0.1082 0.0952 0.1193 0.1050 0.114 0.0619 0.1314 0.1156 0.1091 0.0960 0.1203 0.1059 0.115 0.0624 0.1325 0.1166 0.1101 0.0968 0.1213 0.1067 0.116 0.0629 0.1336 0.1176 0.1110 0.0976 0.1223 0.1076 0.117 0.0634 0.1347 0.1185 0.1119 0.0984 0.1233 0.1085 0.118 0.0640 0,1358 0.1195 0.1128 0.0992 0.1243 0.1094 0.119 0.0645 0.1369 0.1204 0.1137 0.1000 0.1253 0.1103 114 METHODS OF ANALYSIS [Chap. Table 8.— Krober-s Table.— Continued. [Expressed in grams.) FURFDRAI. PHLOROQLUCID FURFURAL ARABIN08E ABABAN XYLOSE XYLAN PENTOSE PENTOSAN 0.120 0.0650 0.1380 0.1214 0.1146 0.1008 0.1263 0.1111 0.121 0.0655 0.1391 0.1224 0.1155 0.1016 0.1273 0.1120 0.122 0.0660 0.1402 0.1233 0.1164 0.1024 0.1283 0.1129 0.123 0.0665 0.1413 0.1243 0.1173 0.1032 0.1293 0.1138 0.124 0.0671 0.1424 0.1253 0.1182 0.1040 0.1303 0.1147 0.125 0.0676 0.1435 0.1263 0.1192 0.1049 0.1314 0.1156 0.126 0.0681 0.1446 0.1272 0.1201 0.1057 0.1324 0.1165 0.127 0.0686 0.1457 0.1282 0.1210 0.1065 0.1334 0.1174 0.128 0.0691 0 . 1468 0.1292 0.1219 0.1073 0 . 1344 0.1183 0.129 0.0697 0.1479 0.1301 0.1228 0.1081 0.1354 0.1192 0.130 0.0702 1490 0.1311 0.1237 0.1089 0.1364 0.1201 0.131 0.0707 0.1501 0.1321 0.1246 0.1097 0.1374 0.1210 0.132 0.0712 0.1512 0.1330 0.1255 0.1105 0.1384 0.1219 0.133 0.0717 0.1523 0.1340 0.1264 0.1113 0.1394 0.1227 0.134 0.0723 0.1534 0.1350 0.1273 0.1121 0.1404 0.1236 0.135 0.0728 0.1545 0.1360 0.1283 0.1129 0.1414 0.1244 0.136 0.0733 0.1556 0.1369 0.1292 0.1137 0.1424 0.1253 0.137 0.0738 0.1567 0.1379 0.1301 0.1145 0.1434 0.1262 0 138 0.0743 0.1578 0.1389 0.1310 0.1153 0.1444 0.1271 0.139 0.0748 0.1589 0.1398 0.1319 0.1161 0.1454 0.1280 0.140 0.0754 0.1600 0.1408 0.1328 0.1169 0.1464 0.1288 0.141 0.0759 0.1611 0.1418 0.1337 0.1177 0.1474 0 . 1297 0.142 0.0764 0.1622 0.1427 0.1346 0.1185 0.1484 0.1306 0.143 0.0769 0.1633 0.1437 0.1355 0.1193 0.1494 0.1315 0.144 0.0774 0.1644 0.1447 0.1364 0.1201 0.1504 0.1324 0.145 0.0780 0.1655 0.1457 0.1374 0.1209 0.1515 0.1333 0.146 0.0785 0.1666 0.1466 0.1383 0.1217 0.1525 0.1342 0.147 0.0790 0.1677 0.1476 0.1392 0.1225 0.1535 0.1351 0.148 0.0795 0.16.88 0.1486 0.1401 0.1233 0.1545 0.1360 0.149 0.0800 0.1699 0.1495 0.1410 0.1241 0.1555 0.1369 0.150 0.0805 0.1710 0.1505 0.1419 0.1249 0.1565 0.1377 0.151 0.0811 0.1721 0.1515 0.1428 9.1257 0.1575 0.1386 0.152 0.0816 0.1732 0.1524 0.1437 0.1265 0.1585 0.1395 0.153 0.0821 0.1743 0.1534 0.1446 0.1273 0.1595 0.1404 0.154 0.0826 0.1754 0.1544 0.1455 0.1281 0.1605 0.1413 0.155 0.0831 0.1765 0.1554 0.1465 0.1289 0.1615 0.1421 0.156 0.0837 0.1776 0.1563 0.1474 0.1297 0.1625 0.1430 0.157 0.0842 0.1787 0.1573 0.1483 0 . 1305 0.1635 0.1439 0.158 0.0847 0.1798 0.1583 0.1492 0.1313 0.1645 0.1448 0.159 0.0852 0.1809 0.1592 0.1501 0.1321 0.1655 0.1457 0.160 0.0857 0.1820 0.1602 0.1510 0.1329 0.1665 0.1465 0.161 0.0863 0.1831 0.1612 0.1519 0.1337 0.1675 0.1474 0.162 0.0868 0.1842 0.1621 0.1528 0.1345 0.1685 0.1483 0.163 0.0873 0.1853 0.1631 0.1537 0.1353 0.1695 0.1492 0.164 0.0878 0.1864 0.1640 0.1546 0.1361 0.1705 0.1501 vm] 65 FOODS AND FEEDING STUFFS Table 8.— Krober-s Table. — Continued. (Expressed in grams.) 115 PURFDRA.I, PHI-OROOLCCID FURFUR.M. AR.VBINO.SE ARA.BA.N XYLOSE XTLAN pento.se PBNTOSAK 0.165 0.0883 0.1S75 0.1650 0.1556 0 . 1369 0.1716 0.1510 0.166 0.0SS8 0.1SS6 0.1660 0.1565 0.1377 0.1726 0.1519 0.167 0.0894 0.1897 0.1669 0.1574 0.1385 0.1736 0.1528 0.168 0.0899 0 . 1908 0.1679 0.1583 0.1393 0.1746 0.1537 0.169 0.0904 0.1919 0.1688 0.1592 0.1401 0.1756 0.1546 0.170 0.0909 0.1930 0.1698 0.1601 0.1409 0.1766 0.1554 0.171 0.0914 0.1941 0.1708 0.1610 0.1417 0.1776 0.1563 0.172 0.0920 0.1952 0.1717 0.1619 0.1425 0.1786 0.1572 0.173 0.0925 0.1963 0.1727 0.1628 0.1433 0.1796 0.1581 0.174 0.0930 0.1974 0.1736 0.1637 0.1441 0.1806 0.1590 0.175 0.0935 0.1985 0.1746 0.1647 0.1449 0.1816 0.1598 0.176 0.0940 0.1996 0.1756 0.1656 0.1457 0.1826 0.1607 0.177 0.0946 0.2007 0.1765 0.1665 0.1465 0.1836 0.1616 0.178 0.0951 0.2018 0.1775 0.1674 0.1473 0 . 1846 0.1625 0.179 0.0956 0.2029 0.1784 0.1683 0.1481 0.1856 0.1634 0.180 0.0961 0.2039 0.1794 0.1692 0.1489 0.1866 0.1642 0.181 0.0966 0.2050 0.1804 0.1701 0.1497 0.1876 0.1651 0.182 0.0971 0.2061 0.1813 0.1710 0.1505 0.1886 0.1660 0.183 0.0977 0.2072 0.1823 0.1719 0.1513 0.1896 0.1669 0.184 0.0982 0.2082 0.1832 0.1728 0.1521 0.1906 0.1678 0.185 0.0987 0.2093 0.1842 0.1738 0.1529 0.1916 0.1686 0.186 0.0992 0.2104 0.1851 0.1747 0.1537 0.1926 0.1695 0.187 0.0997 0.2115 0.1861 0.1756 0.1545 0.1936 0.1704 0.188 0.1003 0.2126 0.1870 0.1765 0.1553 0.1946 0.1712 0.189 0.1008 0.2136 0.1880 0.1774 0.1561 0.1955 0.1721 0.190 0.1013 0.2147 0.1889 0.1783 0.1569 0.1965 0.1729 0.191 0.1018 0.2158 0.1899 0.1792 0.1577 0.1975 0.1738 0.192 0.1023 0.2168 0.1908 0.1801 0.1585 0.1985 0.1747 0.193 0.1028 0.2179 0.1918 0.1810 0.1593 0.1995 0.1756 0.194 0.1034 0.2190 0.1927 0.1819 0.1601 0.2005 0.1764 0.195 0 . 1039 0.2201 0.1937 0.1829 0.1609 0.2015 0.1773 0.196 0.1044 0.2212 0.1946 0.1838 0.1617 0.2025 0.1782 0.197 0 . 1049 0 2222 0.1956 0 . 1847 0.1625 0.2035 0.1791 0.198 0.1054 0^2233 0.1965 0.1856 0.1633 0.2045 0.1800 0.199 0.1059 0.2244 0.1975 0.1865 0.1641 0.2055 0.1808 0.200 0.1065 0.2255 0.1984 0.1874 0.1649 0.2065 0.1817 0.201 0.1070 0.2266 0.1994 0.1883 0.1657 0.2075 0.1826 0.202 0.1075 0.2276 0.2003 0.1892 0.1665 0.2085 0.1835 0.203 0.1080 0.2287 0.2013 0.1901 0.1673 0.2095 0.1844 0.204 0.1085 0.2298 0.2022 0.1910 0.1681 0.2105 0.1853 0.205 0.1090 0.2309 0.2032 0.1920 0.1689 0.2115 0.1861 0.206 0.1096 0.2320 0.2041 0.1929 0.1697 0.2125 0.1869 0.207 o.iini 0.2330 0.2051 0.1938 0.1705 0.2134 0.1878 0.208 0.1106 0.2341 0.2060 0.1947 0.1713 0.2144 0.1887 0.209 0.1111 0.2352 0.2069 0.1956 0.1721 0.2154 0.1896 116 65 METHODS OF ANALYSIS Table 8.— Krober's Table.— Continued. [Chap. [E xpres.sed in grams.] FURFURAL PHLOROGl.UCID FURFURAL ARABINOSE ARABAN XYLOSE XYLAN PENTOSE PENTOSAN 0.210 0.1116 0.2363 0.2079 0.1965 0.1729 0.2164 0.1904 0.211 0.1121 0.2374 0.2089 0.1975 0.1737 0.2174 0.1913 0.212 0.1127 0.2384 0.2098 0.1984 0.1745 0.2184 0.1922 0.213 0.1132 0.2395 0.2108 0.1993 0.1753 0.2194 0.1931 0.214 0.1137 0.2406 0.2117 0.2002 0.1761 0.2204 0.1940 0.215 0.1142 0.2417 0.2127 0.2011 0.1770 0.2214 0.1948 0.216 0.1147 0.2428 0.2136 0.2020 0.1778 0.2224 0.1957 0.217 0.1152 0.2438 0.2146 0.2029 0.1786 0.2234 0.1966 0.218 0.1158 0.2449 0.2155 0.2038 0.1794 0.2244 0.1974 0.219 0.1163 0.2460 0.2165 0.2047 0.1802 0.2254 0.1983 0.220 0.1168 0.2471 0.2174 0.2057 0.1810 0.2264 0.1992 0.221 0.1173 0.2482 0.2184 0.2066 0.1818 0.2274 0.2001 0.222 0.1178 0.2492 0.2193 0.2075 0.1826 0.2284 0.2010 0.223 0.11S3 0.2503 0.2203 0.2084 0.1834 0.2294 0.2019 0.224 0.1189 0.2514 0.2212 0.2093 0.1842 0.2304 0.2028 0.225 0.1194 0.2525 0.2222 0.2102 0.1850 0.2314 0.2037 0.226 0.1199 0.2536 0.2232 0.2111 0.1858 0.2324 0.2046 0.227 0.1204 0.2546 0.2241 0.2121 0.1866 0.2334 0.2054 0.228 0.1209 0.2557 0.2251 0.2130 0.1874 0.2344 0.2063 0.229 0.1214 0.2568 0.2260 0.2139 0.1882 0.2354 0.2072 0.230 0.1220 0.2579 0.2270 0.2148 0.1890 0.2364 0.2081 0.231 0.1225 0.2590 0.2280 0.2157 0.1898 0.2374 0.2089 0.232 0.1230 0.2600 0.2289 0.2166 0.1906 0.2383 0.2097 0.233 0.1235 0.2611 0.2299 0.2175 0.1914 0.2393 0.2106 0.234 0.1240 0.2622 0.2308 0.2184 0.1922 0.2403 0.2115 0.235 0.1245 0.2633 0.2318 0.2193 0.1930 0.2413 0.2124 0.236 0.1251 0.2644 0.2327 0.2202 0.1938 0.2423 0.2132 0.237 0.1256 0.2654 0.2337 0.2211 0.1946 0.2433 0.2141 0.238 0.1261 0.2665 0.2346 0.2220 0.1954 0.2443 0.2150 0.239 0.1266 0.2676 0.2356 0.2229 0.1962 0.2453 0.2159 0.240 0.1271 0.2687 0.2365 0.2239 0.1970 0.2463 0.2168 0.241 0.1276 0.2698 0.2375 0.2248 0.1978 0.2473 0.2176 0.242 0.1281 0.2708 0.2384 0.2257 0.1986 0.2483 0.2185 0.243 0.1287 0.2719 0.2394 0.2266 0.1994 0.2493 0.2194 0.244 0.1292 0.2730 0.2403 0.2275 0.2002 0.2503 0.2203 0.245 0.1297 0.2741 0.2413 0.2284 0.2010 0.2513 0.2212 0.246 0.1302 0.2752 0.2422 0.2293 0.2018 0.2523 0.2220 0.247 0.1307 0.2762 0.2432 0.2302 0.2026 0.2533 0.2229 0.248 0.1312 0.2773 0.2441 0.2311 0.2034 0.2543 0.2238 0.249 0.1318 0.2784 0.2451 0.2320 0.2042 0.2553 0.2247 0.250 0.1323 0.2795 0.2460 0.2330 0.2050 0.2563 0.2256 0.251 0.1328 0.2806 0.2470 0.2339 0.2058 0.2573 0.2264 0.2.52 0.1333 0.2816 0.2479 0.2348 0.2066 0.2582 0.2272 0.253 0.1338 0.2827 0.2489 0.2357 0.2074 0.2592 0.2281 0.254 0.1343 0.2838 0.2498 0.2366 0.2082 0.2602 0.2290 vni] 65 FOODS AND FEEDING STUFFS Table 8.— Krober's Table.— Continued. [Expressed in grams.) 117 FURFURAL PHLOROQLUCID FUBFUR.^L ARABIN08E ARABAN XTLOSE XYLAN PENTOSE PENTOSAN 0.255 0.1349 0.2849 0.2508 0.2375 0.2090 0.2612 0.2299 0.256 0.13.54 0.2860 0.2517 0.23S4 0.2098 0.2622 0.2317 0.257 0.1359 0.2870 0.2526 0.2393 0.2106 0.2632 0.2316 0.258 0.1364 0.2881 0.2536 0.2402 0.2114 0.2642 0.2325 0.259 0.1369 0.2892 0.2545 0.2411 0.2122 0.2652 0.2334 0.260 0.1374 0.29'}3 0.2555 0.2420 0.2130 0.2662 0.2342 0.261 0.1380 0.2914 0.2565 0.2429 0.2138 0.2672 0.2351 0.262 0.1385 0.2924 0.2574 0.2438 0.2146 0.2681 0.2359 0.263 0.1390 0.2935 0.2584 0.2447 0.2154 0.2691 0.2368 0.264 0.1395 0.2946 0.2593 0.2456 0.2162 0.2701 0.2377 0.265 0.1400 0.2957 0.26^3 0.2465 0.2170 0.2711 0.2385 0.266 0.1405 0.2968 0.2612 0.2474 0.2178 0.2721 0.2394 0.267 0.1411 0.2978 0.2622 0.2483 0.2186 0.2731 0.2403 0.26S 0.1416 0.2989 0.2631 0.2492 0.2194 0.2741 0.2412 0.269 0.1421 0.3000 0.2641 0.2502 0.2202 0.2751 0.2421 0.270 0.1426 0.3011 0.2650 0.2511 0.2210 0.2701 0.2429 0.271 0.1431 0.3022 0.2660 0.2520 0.2218 0.2771 0.2438 0.272 0.1436 0.3932 0.2669 0.2529 0.2226 0.2781 0.2447 0.273 0.1442 0.3043 0.2679 0.2538 0.2234 0.2791 0.2456 0.274 0.1447 0.3054 0.2688 0.2547 0.2242 0.2801 0.2465 0.275 0.1452 0.3065 0.2698 0.2556 0.2250 0.2811 0.2473 0.276 0.1457 0.3076 0.2707 0.2565 0.2258 0.2821 0.2482 0.277 0.1462 0.3086 0.2717 0.2574 0.2266 0.2830 0.2490 0.278 0.1467 0.3097 0.2726 0.2583 0.2274 0.2840 0.2499 0.279 0.1473 0.3108 0.2736 0.2592 0.2282 0.2850 0.2508 0.280 0.1478 0.3119 0.2745 0.2602 0.2290 0.2861 0.2517 0.281 0.1483 0.3130 0.2755 0.2611 0.2298 0.2871 0.2526 0.282 0.1488 0.3140 0.2764 0.2620 0.2306 0.2880 0.2534 0.283 0.1493 0.3151 0.2774 0.2629 0.2314 0.2890 0.2543 0.284 0.1498 0.3162 0.2783 0.2638 0.2322 0.2900 0.2552 0.285 0.1504 0.3173 0.2793 0.2647 0.2330 0.2910 0.2561 0.286 0.1509 0.3184 0.2802 0.2656 0.2338 0.2920 0.2570 0.287 0.1514 0.3194 0.2812 0.2665 0.2346 0.2930 0.2578 0.288 0.1519 0.3205 0.2821 0.2674 0.2354 0.2940 0.2587 0.289 0.1524 0.3216 0.2831 0.2683 0.2362 0.2950 0.2596 0.290 0.1529 0.3227 0.2840 0.2693 0.2370 0.2960 0.2605 0.291 0.1535 0.3238 0.2850 0.2702 0.2378 0.2970 0.2614 0.292 0.1540 0.3248 0.2859 0.2711 0.2386 0.2980 0.2622 0.293 0.1545 0.3259 0.2868 0.2720 0.2394 0.2990 0.2631 0.294 0.1550 0.3270 0.2878 0.2729 0.2402 0.3000 0.2640 0.295 0.1555 0.3281 0.2887 0.2738 0.2410 0.3010 0.2649 0.296 0.1560 0.3292 0.2897 0.2747 0.2418 0.3020 0.2658 0.297 0.1566 0.3302 0.2906 0.2756 0.2426 0.3030 0.2666 0.29S 0.1571 0.3313 0.2916 0.2765 0.2434 0.3040 0.2675 0.299 0.1576 0.3324 0.2925 0.2774 0.2442 0.3050 0.2684 0.300 0.1581 0.3335 0.2935 0.27S4 0.2450 O.P.^'.eX) 0.2693 118 METHODS OF ANALYSIS [Chap. 66 GALACTAN.— TENTATIVE. Extract a convenient quantity of the substance, representing 2.5-3 grams of the dry material, on a hardened filter with 5 successive portions of 10 cc. of ether, place the extracted residue in a beaker, about 5.5 cm. in diameter and 7 cm. deep, together with 60 cc. of nitric acid of 1.15 sp. gr., and evaporate the solution to exactly one third its volume in a water bath at a temperature of 94°-96°C. After standing 24 hours, add 10 cc. of water to the precipitate, and allow it to stand another 24 hours. The mucic acid has in the meantime crystallized, but it is mixed with considerable material only partially oxidized by the nitric acid. Filter the solution through filter paper, wash with 30 cc. of water to remove as much of the nitric acid as possible, and replace the filter and contents in the beaker. Add 30 cc. of ammonium car- bonate solution, consisting of 1 part ammonium carbonate, 19 parts water, and 1 part strong ammonium hydroxid, and heat the mixture on a water bath, at 80°C., for 15 minutes, with constant stirring. The ammonium carbonate takes up the mucic acid, forming soluble ammonium mucate. Wash the filter paper and con- tents several times with hot water by decantation, passing the washings through a filter paper, to which final' y transfer the material and thoroughly wash. Evapo- rate the filtrate to dryness over a water bath, avoiding unnecessary heating which causes decomposition, add 5 cc. of nitric acid of 1.15 sp. gr., stir thoroughly the mi.xture and allow to stand for 30 minutes. The nitric acid decomposes the am- monium mucate, precipitating the mucic acid; collect this on a tared filter or Gooch, wash with 10-15 cc. of water, then with 60 cc. of alcohol, and a number of times with ether, dry at the temperature of boiling water for 3 hours, and weigh. Mul- tiply the weight of the mucic acid by 1.33, which gives galactose, and multiply this product by 0.9 which gives galactan. CRUDE FIBER.-OFFICIAL. 67 REAGENTS. (a) l.S5% sulphuric acid solution. — Exact strength, determined by titration. (b) 1.25% sodium hydroxid solution. — Exact strength, determined by titration. 68 DETERMINATION. Extract a quantity of the substance, representing about 2 grams of the dry material, with ordinary ether, or use the residus from the determination of the ether extract. To this residue in a 500 cc. flask add 200 cc. of boiling 1.25% sulphuric acid; connect the flask with an inverted condenser, the tube of which passes only a short distance beyond the rubber stopper into the flask, or simply cover a tall coni- cal flask, which is well suited for this determination, with a watch glass or short stemmed funnel, boil at once and cont'nue boiling gently for 30 minutes. A blast of air conducted nto the flask will serve to reduce the frothing of the liquid. Filter through linen and wash with boiling water until the washings are no longer acid; rinse the substance back into the flask with 200 cc. of boiling, 1.25% solution of sodium hydroxid, free or nearly free from sodium carbonate boil at once, and con- tinue boiling gently for 30 minutes as directed above for the treatment with acid, filter at once rapidly, and wash with boiling water until the washings are neutral. The last filtration may be performed upon a Gooch crucible, a linen filter, or a tared filter paper. If a linen filter is used, rinse the crude fiber, after washing is completed, into a flat-bottomed platinum dish by means of a jet of water; evaporate to dryness on a steam bath, dry to constant weight at 110°C., weigh, incinerate completely, and weigh again. The loss in weight is considered to be crude fiber. If a tared filter Vin] FOODS AND FEEDING STUFFS 119 paper is used, weigh in a weighing bottle. In any case the crude fiber after drying to constant weight at 110°C. must be incinerated and the amount of the ash deducted from the original weight. 69 WATER-SOLUBLE ACIDITY OF FEEDS.— TENTATIVE. Weigh 10 grams of the sample into a shaking bottle, add 200 cc. of water, and shake for 15 minutes. Filter the extract through a folded filter and take a 20 cc. aliquot (equivalent to 1 gram of sample) for the titration. Dilute with 50 cc. of water and titrate with N/10 sodium hydroxid, using phenolphthalein as indicator. In reporting the acidity of feeds, state the results in terms of cc. of N/10 sodium hydroxid required for neutralization. BIBLIOGRAPHY. » Z. Ver. Zucker-Ind., 1900, 37 (I): 357; 1913, 63 (I): 25; J. Ind. Eng. Chem., 1913,5:167. » J. Am. Chem. Soc. 1914, 36: 1566. » Ibid., 1906, 28: 663; 1907, 29: 541. «Ibid., 1902, 24: 1082. » Z. Rubenzucker-Ind., 1885, 35 (N. F.22) : 1012. • Ibid., 1889, 39 (N. F. 26) : 734. ' Ibid., 1879, 29 (N. F. 16) : 1034. ' Wein. Tables for the Quantitative Estimation of the Sugars. Translated by Frew. 1896, p. 26. "Ibid., p. 33. »» Z. Rubenzucker-Ind., 1882, 32 (N. F. 19) : 606, 865. 11 U.S. Bur. Chem. Circ. 71. " J. Am. Chem. Soc, 1904. 26: 266. " U. S. Bur. Chem. Bull. 73, p. 173. "J. Landw., 1900,43:379. rX. SACCHARINE PRODUCTS. 1 PREPARATION OF SAMPLE.-TENTATIVE. (a) Liquids {molasses, sirups, etc.). — Mix materials of this class thoroughly. If crystals of sugar are present, dissolve them either by heating gently or by weigh- ing the whole mass, then adding water, heating until completely dissolved and after cooling, re-weighing. Calculate all results to the weight of the original substance. (b) Semisolids (jellies, jams, etc.). — Weigh 50 grams of the sample into a 250 cc. graduated flask. Treat with water, fill to the mark and mix thoroughly. If insoluble material remains, mix uniformly by shaking before taking aliquots for the various determinations. (C) Solids (sugar, confectionery, etc.). — Grind and mix thoroughly materials of this class to secure uniform samples. Moisture. DRYING METHODS. 2 SUGARS.-OFFICIAL. Dry 2-5 grams in a flat dish (nickel, platinum, or aluminium) at the temperature of boiling water for 10 hours; cool in a desiccator and weigh; then dry again for an hour or until there is only a slight change in weight. With some sugars, more especially those of large grain, there is danger of occlu- sion and retention of water. The International Commission for Unifying Methods of Sugar Analysis prescribe drying at 105°-110°C. for normal beet sugars. This temperature is sufficient to expel the last traces of occluded water and is not attended with sufficient decomposition to affect the weight of the product. The drying tem- perature should never exceed 110°C^ MASSECUITES, MOLASSES, AND OTHER LIQUID AND SEMILIQUID PRODUCTS. 3 Drying upon Pumice Stone.— Tentative. Prepare pumice stone of two grades of fineness, one of which will pass through a 1 mm. sieve, the other through a 6 mm. sieve. Make the determination in flat metallic dishes or in shallow, flat-bottomed, weighing bottles. Place a layer of the fine pumice stone, 3 mm. in thickness, on the bottom of the dish, then a layer of the coarse pumice stone 6-10 mm. in thickness, dry and weigh. Dilute the sam- ple with a weighed portion of water so that the diluted material shall contain 20- 30% of solid matter. Weigh into the dish, prepared as described above, an amount of the diluted sample to yield, approximately, 1 gram of dry matter. If this weigh- ing can not be made rapidly, use a weighing bottle provided with a cork through which a pipette passes. Dry in vacuo at 70°C. to constant weight, making trial weighings at intervals of 2 hours. For substances containing little or no levulose or other readily decomposable substance, the drying may be made in a water oven at the temperature of boiling water. 4 Drying upon Quartz Sand.— Tentative. Digest pure quartz sand with strong hydrochloric acid, wash, dry, and ignite. Preserve in a stoppered bottle. 121 122 METHODS OF ANALYSIS [Chap. Place 6-7 grams of the prepared sand and a short stirring rod in a flat-bottomed dish. Dry thoroughly, cool in a desiccator, and weigh. Then add 3-4 grams of the molasses, mix with the sand (if necessary to thoroughly incorporate the two, add a little water), dry in a water oven at the temperature of boiling water for 8-10 hours, stirring at intervals of an hour, cool in a desiccator, and weigh. Stir, heat again for an hour, cool, and weigh. Repeat the heating and weighing until the loss of water in an hour is not greater than 3 mg. '' AREOMETRIC METHODS. (Not applicable to low-grade sugar products, molasses and other materials containing large amounts of non-sugar solids.) SPECIFIC GRAVITY, WATER AND TOTAL SOLIDS. 5 By Means of a Spindle.— Official. The density of juices, sirups, etc., is most conveniently determined by means of the Brix hydrometer. For rough work, or where less accuracy is desired, the Baum6 hydrometer may be used. The Brix spindle should be graduated to tenths. The range of degrees recorded by each individual spindle should be as limited as possible. The solution should be as nearly as practicable of the same tempera- ture as the air at the time of reading, and, if the variation from the temperature of the graduation of the spindle amounts to more than 1°, a correction must be applied according to the table under 6. Before taking the density of a juice, allow it to stand in the cylinder until all air bubbles have escaped, and until all fatty or waxy matter has come to the surface and been skimmed off. The cylinder should be large enough in diameter to allow the hydrometer to come to rest without touch- ing the sides. A table of specific gravities at .. " and per cent by weight of suc- rose is given under 9, and a table for the comparison of specific gravities at ^^g. ', degrees Brix (per cent by weight of sucrose), and degree Baum6 is given under 8. If the sample is too dense to determine the density directly, dilute a weighed portion with a weighed quantity of water, or dissolve a weighed portion and dilute to a known volume with water. In the first instance the per cent of total solids is calculated by the following formula: WS Per cent of solids in the undiluted material = — in which w S = per cent of solids in the diluted material; W = weight of the diluted material; w = weight of the sample taken for dilution. When the dilution is made to a definite volume, the following formula is to be used: Per cent of solids in the undiluted material = „, in which W V = volume of the diluted solution at a given temperature; D = specific gravity of the diluted solution at the same temperature; S = per cent of solids in the diluted solution at the same temperature; W = weight of the sample taken for dilution at the same temperature. If the spindle reading be made at any other temperature than 17.5°C., the re- sult should be corrected according to the following: K] SACCHARINE PRODUCTS 123 Table 9. For correction of the readings of the Brix spindle when made at other than the standard temperature, 17. 5° C. (For temperatures below 17.5°C. the correction is to be subtracted.) TEM- DEGREE BRIX OP THE SOLUTION PERA- TORE 0 5 10 15 20 25 30 35 40 50 60 70 75 °C. 0 0.17 0.30 0.41 0.52 0.62 0.72 0.82 0.92 0.98 1.11 1.22 1.25 1 29 5 0.23 0 30 0.37 0.44 0.52 0.59 0.65 0.72 0.75 0.80 0 88 0.91 0 94 10 0 20 0.26 0.29 0 33 0.36 0.39 0.42 0.45 0.48 0.50 0.54 0.58 0.61 n 0.18 0.23 0.26 0.28 0.31 0.34 0.36 0.39 0.41 0 43 0.47 0.50 0.53 12 0 16 0 20 0 22 0.24 0.26 0.29 0.31 0 33 0.34 0.36 0.40 0.42 0.46 13 0 14 0.18 0 19 0.21 0.22 0.24 0.26 0.27 0.28 0 29 0.33 0.35 0.39 14 0.12 0 15 0 16 0.17 0.18 0.19 0.21 0.22 0.22 0.23 0.26 0.28 0.32 15 0.09 on 0 12 0 14 0.14 0.15 0.16 0.17 0.16 0 17 0.19 0.21 0.25 16 0.06 0 07 0 08 0.09 0.10 0 10 0.11 0.12 0.12 0.12 0.14 0.16 0.18 17 0.02 0.02 0.03 0.03 0.03 0.04 O.W 0.04 0.04 0.04 0.05 0.05 0.06 18 0 02 0.03 0.03 0.03 0 03 0.03 0 03 0 03 0.03 0 03 o.a3 0.03 0.02 19 0.06 0 08 0.08 0.09 0.09 0.10 0.10 0.10 0.10 0 10 0.10 O.OS 0.06 20 0 11 0.14 0.15 0.17 0.17 0.18 0.18 0.18 0 19 0 19 0.18 0.15 0.11 21 0.16 0 20 0.22 0.24 0.24 0.25 0.25 0.25 0.26 0.26 0.25 0.22 0.18 22 0.21 0.26 0.29 0.31 0.31 0.32 0.32 0.32 0.33 0.34 0.32 0.29 0.25 23 0.27 0.32 0 35 0 37 0.38 0.39 0.39 0.39 0.40 0.42 0.39 0..36 0.33 24 0 32 0 38 0.41 0.43 0 44 0.46 0.46 0 47 0.47 0.50 0.46 0.43 0.40 25 0.37 0.44 0.47 0 49 0.51 0.53 0.54 0 55- 0.55 0 58 0.54 0..51 0.48 26 0.43 0.50 0.54 0.56 0.58 0.60 0.61 0.62 0 62 0.66 0.62 0..58 0.55 27 0.49 0.57 0.61 0.63 0.65 0.68 0.6S 0.69 0 70 0.74 0.70 0.65 0.62 28 0.56 0.64 0.68 0.70 0.72 0.76 0.76 0.78 0.78 0 82 0.78 0.72 0.70 29 0.63 0 71 0.75 0.78 0.79 0.84 0.84 0.86 0.86 0.90 0.86 0.80 0.78 30 0.70 0.78 0,82 0.87 0.87 0.92 0.92 0.94 0.94 0.98 0.94 0.88 0.86 35 1.10 1.17 1.22 1.24 1.30 1.32 1.33 1.35 1.36 1.39 1..34 1.27 1.25 40 1.50 1 61 1.67 1.71 1.73 1.79 1.79 1.80 1.82 1.83 1.78 1.69 1.65 50 2.65 2.71 2.74 2.78 2.80 2.80 2.80 2.80 2.79 2.70 2.56 2.51 60 3.87 3.88 3 88 3 88 3.83 3.90 3.82 3.70 3.43 3.41 70 5.17 5.18 5^20 5:i4 5:13 5.10 5'08 5.06 4.90 4.72 4.47 4.35 80 6.62 6.59 6.54 6.46 6.38 6.30 6.26 6.06 5.82 5.50 5.33 90 8.26 8.16 8.06 7.97 7.83 7.71 7.58 7.30 6.96 6.. 58 6.37 100 10.01 9.87 9.72 9.56 9.39 9.21 9.03 8.64 8.22 7.76 7.42 Example. — A sugar solution shows a reading of 30.2° Brix at 30°C. To find the necessary correction for the conversion of this reading to the reading which would have been obtained if the observation had been made at 17.5°C., find the vertical column in the table headed 30° Brix, which is the nearest to the observed reading. Follow down this column until the number is reached which is opposite to the tem- perature of observation — in this case 30°. The number found, 0.92, is to be added to the observed reading. 7 By Means of a Pycnometer. — Official. (a) By specific gravity at —^' — Determine the specific gravity of the solution 20 °c at -|5-" by means of a pycnometer and ascertain the corresponding per cent by weight of sucrose from 9. When the density of the substance is too high for a direct determination, dilute and calculate the sucrose content of the original material aa directed under 5. (b) By specific gravity at -jf^' — Proceed as directed under (a), the determina- 17 5°C 20°C tions of specific gravity being made at -777? ' instead of at -rr^- Ascertain the corre- 17.5° spending per cent by weight of sucrose from 8. The pycnometer deternaination should not 20°C. 17.5°- "^ -i^' made at any other temperature 124 8 METHODS OF ANALYSIS For the comparison of specific gravities at Table 10. 17. 5° C. 17.5° Degree Baume = 146.78 Brix and [Chap. Baumi. 146.78 sp.gr. DEGREE DEGREE DEGREE BHIX OR BRIX OR BBIX OR PER CENT PER CENT PER CENT SPECIFIC DEGREE SPECIFIC DEGREE SPECIFIC DEGREE BY WEIGHT GRAVITY BAUM6 BY WEIGHT GRAVITY BAUMi BY WEIGHT GRAVITY BAUMfi or OF OF SUCROSE SUCROSE SUCROSE 1.0 1.00388 0.6 33.0 1.14423 18.5 65.0 1.31989 35.6 2.0 1.00779 1.1 34.0 1.14915 , 19.05 i 66.0 1.32601 36.1 3.0 1.01173 1.7 35.0 1.15411 ! 19.6 67.0 1.33217 36.6 4.0 1.01570 2.3 36.0 1.15911 20.1 i 68.0 1.33836 37.1 5.0 1.01970 2.8 37.0 1.16413 20.7 i 69.0 1.34460 37.6 6.0 1.02373 3.4 38.0 1.16920 21.2 70.0 1.35088 38.1 7.0 1.02779 4.0 39.0 1.17430 1 21.8 71.0 1.35720 38.6 8.0 1.03187 4.5 40.0 1.17943 1 22.3 72.0 1.36355 39.1 9.0 1.03599 5.1 41.0 1.18460 i 22.9 73.0 1.36995 39.6 10.0 1.04014 5.7 42.0 1.18981 1 23.4 74.0 1.37639 40.1 11.0 1.04431 6.2 43.0 1.19505 j 23.95 75.0 1.38287 40.6 12.0 1.04852 6.8 44.0 1.20033 ! 24.5 76.0 1.38939 41.1 13.0 1.05276 7.4 45.0 1.20565 25.0 77.0 1.39595 41.6 14.0 1.05703 7.9 46.0 1.21100 , 25.6 78.0 1.40254 42.1 15.0 1.06133 8.5 47.0 1.21639 26.1 j 79.0 1.40918 42.6 16.0 1.06566 9.0 48.0 1.22182 1 26.6 80.0 1.41586 43.1 17.0 1.07002 9.6 49.0 1.22728 27.2 I 81.0 1.42258 43.6 18.0 1.07441 10.1 50.0 1.23278 1 27.7 1 82.0 1.42934 44.1 19.0 1.07884 10.7 51.0 1.23832 ! 28.2 i 83.0 1.43614 44.6 20.0 1.08329 11.3 52.0 1.24390 i 28.8 : 84.0 1.44298 45.1 21.0 1.08778 11.8 53.0 1.24951 1 29.3 85.0 1.44986 45.5 22.0 1.09231 12.4 54.0 1.25517 j 29.8 86.0 1.45678 46.0 23.0 1.09686 13.0 55.0 1.26086 1 30.4 87.0 1.46374 46.5 24.0 1 .'10145 13.5 56.0 1.26658 1 30.9 88.0 1.47074 47.0 25.0 1.10607 14.1 i 57.0 1.27235 31.4 89.0 1.47778 47.45 26.0 1.11072 14.6 58.0 1.27816 31.9 ' 90.0 1.48486 47.9 27.0 1.11541 15.2 59.0 1.28400 1 32.5 91.0 1.49199 48.5 28.0 1.12013 15.7 60.0 1.28989 , 33.0 92.0 1.49915 48.9 29.0 1.12488 16.3 61.0 1.29581 1 33.5 93.0 1.50635 49.4 30.0 1.12967 16.8 62.0 1.30177 1 34.0 94.0 1.51359 49.8 31.0 1 . 13449 17.4 63.0 1.30777 1 34.5 95.0 1.52087 50.3 32.0 1.13934 17.95 64.0 1.31381 1 35.1 When the number expressing the specific gravity found by analysis falls between the numbers given in the above table, the exact equivalent in degrees Brix or Baume is found by a simple calculation. Example. — The pycnometer shows the specific gravity of a certain sirup to be 1.20909. The table shows that the corresponding degree Brix is between 45.0 and 46.0. Subtracting the specific gravity of a solution of 45° Brix from the correspond- ing figure for 46°, we have (expressing the specific gravities as whole numbers) 121,100 — 120,565 = 535, the difference in specific gravity for 1° Brix at this point in the table. Subtracting the specific gravity corresponding to 45° from the spe- 344 cific gravity found by analysis, we have 120,909 - 120,565 = 344; -— = 0.64, the frac- OoO tion of 1° Brix more than 45°. The degree Brix, corresponding to a sp. gr. of 1.20909, is therefore 45.64. IX] SACCHARINE PRODUCTS 125 9 Table 11. Densities^ of solutions of cane sugar at 20°C. (This table is the basis for standardizing hydrometers indicating per cent of sugar at 20°C.) TENTHS OF PER CENT PER CENT SUGAR 0 1 2 3 4 5 6 7 8 9 0 0.998234 0.998622 0.999010 0.999398 0.999786 1.000174 1.000563 1.000952 1.001342 1.001731 1 1.002120 1.002509 1.002897 1.003286 1.003675 1.004064 1.004453 1,004844 1.005234 1.005624 2 1.006015 1.006405 1.00079G 1.007188 1. 007580 1.007972 1.008363 1.008755 1.009148 1.009541 3 1 . 009934 1.010327 1.010721 1.011115 1.011510 1.011904 1.012298 1.012694 1.013089 1,013485 4 1.013881 1.014277 1.014673 1.015070 1.015407 1.015864 1.016261 1.016659 1.017058 1,017456 5 1.017854 1.018253 1.018652 1.019052 1.019451 1.019851 1.020251 1.020651 1,021053 1,021454 6 1.021855 1.022257 1.022659 1.023061 1.023463 1.023867 1.024270 1.024673 1.025077 1,025481 7 1.025885 1.026289 1.026694 1.027099 1.027504 1,027910 1.028316 1.028722 1.029128 1,029535 8 1.029942 1.030349 1.030757 1.031165 1.031573 1.031982 1.032391 1.032800 1.033209 1,0.33619 9 1.034029 1.034439 1.034850 1.035260 1.035671 1.036082 1.036494 1.036906 1.037318 1,037730 10 1.038143 1.038556 1.038970 1.039.383 1.039797 1.040212 1. 040626 1.041041 1.041456 1.041872 11 1.042288 1.042704 1.043121 1.043537 1.043954 1.041370 1.014788 1.045206 1.045625 1 . 046043 12 1,046462 1.046881 1.047300 1.047720 1.048140 1.048559 1.048980 1.049401 1.049822 1.050243 13 1.050665 1.051087 1.051510 1.051933 1.052356 1.052778 1.053202 1.053626 1.0.54050 1.054475 14 1.054900 1.055325 1.055751 1.056176 1.056602 1.057029 1.057455 1.057882 1.058310 1.058737 15 1.059165 1.059593 1.060022 1.060451 1.060880 1.061308 1.061738 1,062168 1.062598 1.063029 16 1.063460 1.063892 1.064324 1.064756 1.065188 1.065621 1.066054 1.066487 1.066921 1.067355 17 1.067789 1.068223 1.068658 1.069093 1.069529 1.069964 1.070400 1.070836 1.071273 1.071710 18 1.072147 1.072585 1.073023 1.073461 1.073900 1.074338 1.074777 1.075217 1.075657 1.076097 19 1.076537 1.076978 1.077419 1.077860 1.078302 1.078744 1.079187 1.079629 1.080072 1.080515 20 1.0S0959 1.081403 1.081848 1.082292 1.082737 1.083182 1.083628 1.084074 1.084520 1.084967 21 1.085414 1.085861 1.086309 1.086757 1.087205 1.087652 1.088101 1.088550 1.089000 1.089450 22 1.089900 1.090351 1.090802 1.091253 1.091704 1.092155 1.092607 1.093060 1.093513 1.093966 23 1.094420 1.094874 1.095328 1.095782 1.096236 1.096691 1.097147 1.097603 1.098058 1.098514 24 1.098971 1.099428 1.099886 1.100344 1.100802 1.101259 1.101718 1.102177 1.102637 1 . 103097 25 1.103557 1.104017 1 . 104478 1.104938 1.105400 1.105862 1.106324 1.106786 1.107248 1.107711 26 1.108175 1.108639 1.109103 1 . 109568 1.110033 1.110497 1.110963 1.111429 1.111895 1.112361 27 1.112828 1.113295 1.113763 1.114229 1.114697 1.115166 1.115635 1.116104 1,116572 1.117042 28 1.117512 1.117982 1.118453 1.118923 1.119395 1.119867 1.120339 1.120812 1,121284 1.121757 29 1.122231 1.122705 1.123179 1.123653 1.124128 1 . 124603 1.125079 1.125555 1,126030 1.126507 30 1.126984 1.127461 1.127939 1.128417 1.128896 1.129374 1,129853 1.130332 1.130812 1.131292 31 1.131773 1.132254 1.132735 1.13.3216 1.133698 1.134180 1.134663 1.135146 1 . 135628 1.136112 32 1.136596 1.137080 1.137565 1 . 138049 1.138534 1.139020 1.139506 1 . 139993 1.140479 1.140966 33 1.141453 1.141941 1.142429 1.142916 1.143405 1.143894 1.144384 1.144874 1 . 145363 1 . 14.5854 34 1.146345 1.146836 1.147328 1.147820 1.148313 1.148805 1.149298 1.149792 1.150286 1.150780 35 1.151275 1.151770 1.152265 1.152760 1.153256 1.153752 1.154249 1 . 154746 1.155242 1.155740 36 1.156238 1.156736 1.157235 1.157733 1.158233 1.158733 1.159233 1.159733 1.160233 1 . 160734 37 1.161236 1.161738 1.162240 1.102742 1.163245 1.163748 1.164252 1.164756 1.165259 I . 165764 38 1 . 166269 1.166775 1.167281 1.167786 1.168293 1.168800 1.169307 1.169815 1.170322 1.170831 39 1.171340 1.171849 1.172359 1.172869 1.173379 1.173889 1.174400 1.174911 1.175423 1.175935 40 1.176447 1.176960 1.177473 1.177987 1.178501 1.179014 1.179527 1.180044 1 . 180560 1.181078 41 1.1S1592 1.182108 1 . 182625 1.183142 1.183660 1.184178 1.184696 1.185215 1 . 185734 1.186253 42 1.186773 1.187293 1.187814 1 . 188335 1.188856 1 . 189379 1.189901 1.190123 1.190946 1.191469 43 1.191993 1.192517 1.193041 1.193565 1 . 194090 1.194616 1.195141 1.195667 1.196193 1 . 196720 44 1 . 197247 1.197775 1.198303 1.198832 1.199360 1.199890 1.200420 1.200950 1.201480 1.202010 45 1.202540 1.203071 1.203603 1.204136 1.204668 1.205200 1.205733 1.206266 1.206801 1.207335 46 1.207870 1.208405 1.208940 1.209477 1.210013 1.210549 1.211086 1.211623 1.212162 1.212700 47 1.213238 1.213777 1.214317 1.214856 1.215395 1.215936 1.216476 1.217017 1.217559 1.218101 48 1.218643 1.219185 1.219729 1.220272 1.220815 1.221360 1.221904 1.222449 1.222995 1.223540 49 1.224086 1.224632 1.225180 1.225727 1.226274 1.226823 1.227371 1.227919 1.228469 1.229018 50 1.229567 1.230117 1.230668 1.231219 1.231770 1.232322 1.232S74 1.233426 1.233979 1.234532 51 1.235085 1.235639 1.236194 1.236748 1.237303 1.237859 1.238414 1.238970 1.239527 1.240084 52 1.240641 1.241198 1.241757 1.242315 1.242873 1.243433 1.243992 1.244552 1.245113 1.245673 53 1.246234 1.246795 1.247358 1.247920 1.248482 1.249046 1.249609 1.250172 1.250737 1.251301 54 1.251866 1.252431 1.252997 1.253563 1.254129 1.254697 1.255264 1.255831 1.256400 1.256967 55 1.257535 1.258104 1.258674 1.259244 1.259815 1.260385 1.260955 1.261527 1.262099 1.262671 56 1.263243 1.263816 1.264390 1.264963 1.265537 1.266112 1.266686 1.267261 1.267837 1.268413 57 1.268989 1.269565 1.270143 1.270720 1.271299 1.271877 1.272455 1.273035 1.273614 1.274194 58 1.274774 1.275354 1.275936 1.276517 1.277098 1.277680 1.278262 1.278844 1.279428 1.280011 59 1.280595 1.281179 1.281764 1.282349 1.282935 1.283521 1.284107 1.284694 1.285281 1.285869 126 METHODS OF ANALYSIS [Chap. Table 11.— Continued. Densities of solutions of cane sugar at 20° C. TENTHS OP PER CENT 1.2S6456 1.292354 1.298291 1.304267 1.310282 1 316334 1.322425 1.328554 1.334722 1.341 1.347174 1.353456 1.359778 1.366139 1.372536 1.378971 1.385446 1.391956 1.398505 1.405091 1.411715 1.418374 1.425072 1.431807 1.438579 1 .445388 1.452232 1.459114 1.466032 1.472986 1.479976 1 .487002 1.494063 1.501158 1.508289 1.515455 1.522656 1.529891 1.537161 1.544462 1.551800 1.287044 1.292946 1.298886 1.304867 1.310885 1.316941 1.323036 1.329170 1.335342 1.341551 1.347801 1.354087 1.360413 1.366777 1.373178 1.379617 1.386096 1.392610 1.399162 1.405752 1.41 1.419043 1.425744 1.432483 1.439259 1.446071 1.452919 1.459805 1.466726 1.473684 1.480677 1.487707 1.494771 1.501870 1.509004 1.516174 1.523378 1.530616 1.537889 1.545194 1.287633 1.293539 1.299483 1.305467 1.3114S9 1.317549 1.323648 1.329785 1.335961 1.342174 1.348427 1.35471 1.36104 1.367415 1.373820 1.380262 1.386745 1.393263 1.39! 1.406412 1.413044 1.419711 1.426416 1.433158 1.446754 1.453605 1.460495 1.467420 1.474381 1.481378 1.488411 1.4954? 1.50258; 1.509720 1.516893 1.524100 1.531342 1.538618 1.5459: 1.288222 1.294131 1.300079 1.306068 1.312093 1.318157 1.324259 1.330401 1.336581 1.342798 1.319055 1.355349 1.361682 1.36: 1.374463 1.380909 1.387396 1.393917 1.400477 1.407074 1.413709 1.420380 1.42 1.433835 1.440619 1.447438 1.454292 1.461186 1.468115 1.475080 1.482080 1.489117 1.496188 1.503293 1.510435 1.517612 1.524823 1.5.32068 1.539347 1.543659 1.289401 1.295318 1.301274 1.307271 1.313304 1.319374 1.325484 1.331633 1.337821 1.344046 1.350311 1.356612 1.362953 1.36! 1 .375749 1.382203 1.388696 1.395226 1.401793 1.408398 1.455668 1.462568 1.469504 1.476477 1.4834S4 1.490528 1.497606 1.504719 1.511868 1.519051 1.526269 1.5335: 1.319983 1.32( 1.332250 1.338441 1.344671 1.382851 1.389347 1.395881 1.402452 1.409061 1.415706 1.422390 1.429109 1.435866 1.442661 1.449491 1.456357 1.463260 1 470200 1.477176 1.484187 1.491234 1.498316 1.505432 1.512585 1.351568 1.357877 1.364226 1.370613 1.377036 1.383499 1.389999 1.390536 1.403111 1.409723 1.416373 1.423059 1.429782 1.436543 1.443342 1.450175 1.457045 1.463953 1.47( 1.477876 1.520492 1.527717 1.534976 1.542267 1.549595 1.291172 1.297100 1.303068 1.309077 1.315121 1.321203 1.327325 1.333485 1.339684 1.345922 1.352197 1.35851 1.364864 1.371254 1.377680 1.384148 1.390651 1 .397192 1.403771 1.410387 1.417039 1.423730 1.430457 1.437222 1.444024 1.450860 1.457735 1.464645 1.471592 1.478575 1.485593 1.49264 1.49973 1.506859 1.514019 1.521212 1.528441 1.535704 1.542998 1.550329 1.352827 1.359144 1.365501 1.371894 1.378326 1.384796 1.391303 1.397848 1.404430 1.411051 1.417707 1.424400 1.431131 1.437900 1.444705 1.451545 1.458424 1.465338 1.472289 1.479275 1.486297 1.493355 1.500447 1.507574 1.514737 10 REFRACTOMETER METHOD.— TENT A TIVE. Determine the refractive index of the solution at 28°C. and obtain the corre- sponding percentage of dry substance from 11. If the refractive index is obtained at a temperature other than 28°C., correct the result as indicated in 12. If the solution is too dark to be read in the instrument, dilute with a concentrated sugar solution. Water should never be used for this purpose. Mix weighed amounts of the solution under examination and a solution of pure sugar of about the same strength, and obtain the amount of dry substance in the former by the following formula: m SACCHARINE PRODUCTS 127 (A + B) C - BD in which X = per cent of dry substance to be found; A = weight in grams of the material mixed with B; B = weight in grams of pure sugar solution employed in the dilution; C = per cent of dry substance in the mixture of A and B obtained from the refractive index; D = per cent of dry substance in the pure sugar solution obtained from its refractive index. 11 Table 12.— Geerligs'' Table. For dry substance in sugar-house products by the Abbe ref Tactometer, at 28°C. INDEX PER CENT DRY DECIMALS TO BE ADDED FOR INDEX PER CENT DRY DECIMALS TO BE ADDED FOR INDEX PER CENT DRY DECIMALS TT BE ADHED FOR SUB- STANCE FR.\CTIONAL READINGS* 80B- .STANCB FRACTIONAL READINl^S* SUB- STANCE FRACTIONAL READINOS* 1.3335 1 0.0001 = 0.05 1.3484 11 0 0001 = 0.05 1.3746 27 0 0001 - 0 05 1.3349 1.3364 2 3 0 0002 = 0 1 0.0003 = 0.2 0 0001 = 0.25 1.3500 1.3516 12 13 0 0002 = 0 1 0.0003 = 0.2 0 0004 = 0.25 1.3764 1.3782 28 29 0 0002 = 0 1 0.0003 = 0.15 0 0004 = 0.2 1.3379 4 0.0005 = 0.3 1.3530 14 0.0005 = 0.3 1.3800 30 0.0005 = 0 25 1.3394 1.3409 5 6 0 000fi = 0.4 0.0007 = 0.5 0 OUOS = 0 6 1.3546 1.3562 15 16 0 0006 = 0.4 0.0007 = 0.45 0.0008 = 0.5 1.3818 1.3836 31 32 0 0006 = 0.3 0 0007 = 0 35 0.0008=0 4 1.3424 7 0 0009 = 0,7 1.3578 17 0.0009 = 0.6 1.3854 33 0.0009 = 0.45 1.3439 1.3454 8 9 0.0010 = 0 75 0.0011 = 0.8 0 0012 = 0 8 1.3594 1.3611 18 19 0 0010 = 0.65 0.0011 = 0.7 0.0012 = 0.75 1.3872 1.3890 34 35 0.0010=0 5 0.0011 = 0 55 0 0012 = 06 1.3469 10 0 0013 = 0 85 1.3627 20 0 0013 = 0.8 1.3909 36 0 0013 = 0.65 0.0014 = 0 9 00015= 1.0 1.3644 1.3661 21 22 0.0014 = 0.85 0 0015 = 09 0.0016=0.95 1.3928 1.3947 37 38 0 0014 = 0 7 0 (015 = 0.75 0 '016 = 0 8 1.3678 23 1.3966 39 0 0017 = 0 85 1.3695 1.3712 24 25 1.3984 1.4003 40 41 0 0018 = 09 0 0019 = 0 95 0.0020 = 1 0 1.3729 26 0.0^v21= 10 1.4023 42 0.0 01 = 0 05 1.4292 55 0.0001 = 0.05 1.4711 73 0 0001 = 0 0 1.4043 1.4063 43 44 0 0002 = 0.1 0.0003 = 0.15 0.0004= 0 2 1.4314 1.4337 56 57 0 0002 = 0 1 0 0003 = 0 1 0 0004 = 0 15 1.4736 1.4761 74 75 0.0002 = 0 05 0.0003 = 0 1 0 0004 = 0 15 1.4083 45 0 0005 = 0 25 1.4359 58 0 0005 = 0 2 1.4786 76 0 0005=0.2 1.4104 1.4124 46 47 0 0006= 0.3 0.0007= 0 35 O.OOOS = 04 1.4382 1.4405 59 60 0.0006 = 0 25 0 0007 = 0 3 0.0008 = 0 35 1.4811 1.4836 77 78 0 0006 =02 0.0007 = 0 25 0 OOOS = 03 1.4145 48 0.0009 = 0 45 1.4428 61 0.0009 = 0 4 1.4862 79 0 0009 = 0.35 1.4166 1.4186 49 50 0 0010 = 05 0 0011 = 0 55 0 0012 = 0 0 1.4451 1.4474 62 63 0 0010 = 0.45 0 onii = 05 0 0012 = 0.5 1.4888 1.4914 80 81 0 0010 = 0 35 00011 = 0 4 0 0012 = 0 45 1.4207 51 0.0013 = 0 65 1.4497 64 0 0.il3 = 0 55 1.4940 82 0 oon = 05 1.4228 1.4249 52 53 0 0014 = 0 7 0 0015 = 0 75 0.0016= 08 1.4520 1.4543 65 66 0 0014 = 06 0 0015 = 0 65 0 0016 = 0 7 1.4966 1.4992 83 84 0 0014 = 05 0 0015 = 0 55 0 0016 = 06 1.4270 54 0.0017 = 0 85 1.4567 67 0 0017 = 0 75 1.5019 85 0 0017 = 0 65 0 0018 = 0 9 1.4591 68 0.0018 = 0 8 1 5046 86 0 0018 = 0 65 0 0019 = 0.95 0 0020 = 1 0 1.4615 69 0 0019 = 0 85 0 0020 = 09 1.5073 87 0 0019= 0 7 0 0020 = 0 75 0.0021 = 1.0 1.4639 70 0 0021 = 0.9 1.5100 88 0 0021 =08 1.4663 71 0.0022 = 0.95 1 5127 89 0 0022 = 08 1.4687 72 0 0023= 10 0.0024= 1.0 1.5155 90 0 0023 = 0.85 0 0024 = 09 0 0025 = 0 9 0 0026= 0 95 0 0027= 10 0 0028= 10 *Find in the table the refractive index which is next lower than the reading actu- ally made and note the corresponding whole number for the per cent of dry substance Subtract the refractive index obtainod from the table from the observed reading; the decimal corresponding to this difference, as given in the column so marked, is added to the whole per cent of dry substance as first obtained. 128 12 METHODS OF ANALYSIS Table 13. Corrections for temperature. [Chap. DRV SUBSTANCE T0RE OF THE 0 5 10 15 20 25 30 40 50 60 70 80 90 PRISMS IN "C. Subtract - 20 0.53 0.54 0.55 0.56 0.57 0.58 0.60 0.62 0.64 0.62 0.61 0.60 0.58 21 0.46 0.47 0.48 0.49 0.50 0.51 0.52 0.54 0.56 0.54 0.53 0.52 0.50 22 0.40 0.41 0.42 0.42 0.43 0.44 0.45 0.47 0.48 0.47 0.46 0.45 0.44 23 0.33 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.40 0.39 0.38 0.38 0.38 24 0.26 0.26 0.27 0.28 0.28 0.29 0.30 0.31 0.32 0.31 0.31 0.30 0.30 25 0,20 0.20 0.21 0.21 0 22 0.22 0.23 0.23 0.24 0.23 0.23 0.23 0.22 26 0.12 0.12 0.13 0.14 0.14 0.15 0.15 O.IP 0.16 0.16 0.15 0.15 0.14 27 0.07 0.07 0.07 0.07 0.07 0.07 0.0? 0.08 0.08 0.08 0.08 0.08 0.07 Add- 29 0.07 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.07 30 0.12 0.12 0.13 0.14 0.14 0.14 0.15 0.15 0.16 0.16 0.16 0.15 0.14 31 0.20 0.20 0.21 0.21 0.22 0.22 0.23 0.23 0.24 0.23 0.23 0.23 0.22 32 0.26 0.26 0.27 0.28 0.28 0.29 0.30 0.31 0.32 0.31 0.31 0.30 0.30 33 0.33 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.40 0.39 0.38 0.38 0.38 34 0.40 0.41 0.42 0.42 0.43 0.44 0.45 0.47 0.48 0.47 0.46 0.45 0.44 35 0.46 0.47 0.48 0.49 0.50 0.51 0.52 0.54 0.56 0.54 0.53 0.52 0.50 13 Method I.— Official. Heat 5-10 grams of the sample in a 50-100 cc. platinum dish at 100°C. until the water is expelled, add a few drops of pure olive oil, and heat slowly over a flame until swelling ceases. Then place the dish in a muffle and heat at low redness until a white ash is obtained. 14 Method II.— Official. Carbonize the mass at a low heat, dissolve the soluble salts in hot water, burn the residual mass as directed in 13, add the solution of soluble salts, and evaporate to dryness at 100°C., ignite gently, cool in a desiccator, and weigh. 1 5 Method III.— Official. Saturate the sample with sulphuric acid, dry, ignite gently, then burn in a muf- fle at low redness. Deduct one tenth of the weight of the ash, and calculate the per cent. 1 6 QUANTITATIVE ANALYSIS OF THE ASH.— OFFICIAL. Proceed as directed under III. 1 7 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE. Ash the material as directed under 13 or 14. Add water to the ash in the plati- num dish, heat nearly to boiling, filter through an ashless filter paper, and wash with hot water until the combined filtrate and washings measure about 60 cc. Re IX] SACCHARINE PRODUCTS 129 turn the filter paper and contents to the platinum dish, ignite carefully, and weigh. Calculate the percentages of water-soluble and water-insoluble ash. 1 8 ALKALINITY OF THE SOLUBLE ASH.-TENTATIVE, Cool the filtrate from 1 7 and titrate with N/10 hydrochloric acid, using methyl orange as an indicator. Express the alkalinity in terms of the number of cc. of N/10 acid per 1 gram of the sample. 19 ALKALINITY OF THE INSOLUBLE ASH.-TENTATIVE. Add an excess of N/10 hydrochloric acid (usually 10-15 cc.) to the ignited insolu- ble ash in the platinum dish, under 1 7, heat to boiling over an asbestos plate, cool, and titrate the excess of hydrochloric acid with N/10 sodium hydroxid, using methyl orange as an indicator. Express the alkalinity in terms of the number of cc. of N/10 acid per 1 gram of the sample. 20 MINERAL ADULTERANTS IN THE ASH.-TENTATIVE. Mix 100 grams of molasses, sirup, honey, or the confectionery solution prepared as directed under 1 (b) and evaporate to a sirupy consistency, with about 35 grams of concentrated sulphuric acid in a large porcelain evaporating dish. Pass an electric current through it while stirring by placing one platinum electrode in the bottom of the dish near one side and attaching the other to the lower end of the glass rod with which the contents are stirred. Begin with a current of about 1 ampere and graduallj'- increase to 4 (modified from method of Budde and Schou* for determining nitrogen electrolytically). In 10-15 minutes the mass is reduced to a fine dry char, which may be readily burnt to a white ash in the original dish over a free flame or in a muffle. This method^ is preferred to the ordinary method of heating with sulphuric acid, especially in the case of molasses, because, if properly manipulated, it comes quietly into the form of a very finely divided char or powder, especially adapted for subse- quent quick ignition. If an electric current is not available, treat in a large porcelain dish 100 grams of the saccharine solution, evaporated to a sirupy consistency, with suflBcient concen- trated sulphuric acid to thoroughly carbonize the mass and ignite in the usual manner. The following adulterants may be present: salts of tin, used in molasses to bleach; mineral pigments, such as chromate of lead in yellow confectionery; oxid of iron, sometimes used to simulate the color of chocolate; and copper. These elements may be detected by the usual qualitative tests. 21 NITROGEN.— TENTATIVE. Determine nitrogen in 5 grams of the material as directed under I, 18, 21 or 23, using a larger quantity of the sulphuric acid if necessary for complete digestion. SUCROSE. 22 Method I.— Tentative. (Substances in which the volume of the combined insoluble matter and precipitate from clarifying agents is less than 1 cc. from 26 grams.) Determine sucrose by polarization before and after inversion, as directed under VIII. 14. 130 METHODS OF ANALYSIS [Chap. All products which contain dextrose or other reducing sugars in the crystalline form, or in supersaturated solution, exhibit the phenomenon of birotation. The con- stant rotation only should be employed in the Clerget formula, and to obtain this the solutions prepared for direct polarization should be allowed to stand overnight before making the reading. If it is desired to make the direct reading immediately, the birotation may be destroyed by heating the neutral solution to boiling for a few minutes or by adding a few drops of strong ammonium hydroxid before completing the volume. 23 Method II. {Double dilution method.^)— Tentative. (Substances in which the volume of the combined insoluble matter and precipitate from clarifying agents is more than 1 cc. from 26 grams.) Weigh out a half normal weight of the sample and make up the solution to 100 cc, employing the appropriate clarifier (basic lead acetate for dark colored con- fectionery or molasses and alumina cream for light colored confectionery). Also weigh out a normal weight of the sample and make up a second solution with the clarifier to 100 cc. Filter and obtain direct polariscopic readings of both solu- tions. Invert each solution as directed in 22 and obtain its invert reading. The true direct polarization of the sample is the product of the two direct read- ings divided by their difference. The true invert polarization is the product of the two invert readings divided by their difference. Calculate the sucrose from the true polarizations thus obtained by the formula given under VIII, 14. COMMERCIAL GLUCOSE (APPROXIMATE). 24 Method I— Tentative. (Substances containing little or no invert sugar.) Commercial glucose can not be determined accurately owing to the varying amounts of dextrin, maltose, and dextrose present in this product. However, in sirups, in which the amount of invert sugar is so small as not to appreciably affect the result, commercial glucose may be estimated approximately by the following formula:^ ^ (a - S) 100 . , . , G = in which 175 G = per cent of commercial glucose; a = direct polarization; S = per cent of cane sugar. Express the results in terms of commercial glucose polarizing +175°V. Method II. — Tentative. 25 (Substances containing invert sugar.') Prepare an inverted half normal solution of the substance as directed under VIII, 14 except that after inversion cool the solution, make neutral to phenol- phthalein with sodium hydroxid solution, slightly acidify with hydrochloric acid, and treat with 5-10 cc. of alumina cream before making up to the mark. Filter and polarize at 87°C. in a 200 mm. jacketed tube. Multiply the reading by 200 and divide by the factor 103 to express the amount of glucose present in terms of glu- cose polarizing +175°V. IXl SACCHARINE PRODUCTS 131 26 REDUCING SUGARS.— TENTATIVE. Determine either as dextrose or invert sugar as directed under VIII, 50, 51, 52, 54, or 21, 23, 25, 36 or 39. 27 STARCH.-TENTATIVE. Measure 25 cc. of a solution or uniform mixture, prepared as directed in 1 (b), (representing 5 grams of the sample) into a 300 cc. beaker, or introduce 5 grams of the finely ground sample (previously extracted with ether if the sample contains much fat) into the beaker, add sufficient water to make the volume 100 cc, heat to about 60°C. (avoiding if possible gelatinizing the starch) and allow to stand for about an hour, stirring frequently to secure complete solution of the sugars. Transfer to a stout wide-mouthed bottle, rinse the beaker with a little warm water, cool, add an equal volume of 95% alcohol, mix, and allow to stand at least an hour. Centrifugalize until the precipitate is closely packed on the bottom of the bottle and decant the supernatant liquid through a hardened filter. Wash the precipi- tate with successive 50 cc. portions of 50% alcohol by centrifugalizing and decant- ing through the filter until 3 or 4 drops of the washings give no test for sugar with alphanaphthol as described under 68. Transfer the residue from the bottle and the hardened filter to a large flask and determine starch as directed under VIII, 60. ETHER EXTRACT IN CONFECTIONERY. 28 Continuous Extraction. — Tentative. (1) Measure 25 cc. of a 20% mixture or solution, prepared as directed under 1 (b), intoa very thin, readily frangible, glass evaporating shell {Hofmeister Schalchen), containing 5-7 grams of freshly ignited asbestos fiber; or (2) If impossible to ob- tain a uniform sample, weigh 5 grams of the mixed finely divided sample into a dish, and wash with water upon the asbestos in the evaporating shell, using, if neces- sary, a small portion of the asbestos fiber on a stirring rod to transfer the last traces of the sample from the dish to the shell. Dry to constant weight at 100°C., cool, wrap loosely in smooth paper, crush into rather small fragments between the fin- gers, transfer carefully the crushed mass, exclusive of the paper, to an extraction tube or a fat extraction cartridge. A thin lead disk (bottle cap) may be substituted for the Schalchen. The disk may then be cut into small pieces and placed in the extraction tube. Extract with anhydrous ether or petroleum ether (b. p. 45°-60''C. and without weighable residue) in a continuous extraction apparatus for at least 25 hours. In most cases it is advisable to remove the substance from the extractor after the first 12 hours, grind with sand to a fine powder, and re-extract for the re- maining 13 hours. Transfer the extract to a tared flask, evaporate the solvent, dry to constant weight in an oven at lOO'C. 29 Roese-Gottlieb Method. — Tentative. Substances such as butter-scotch, invariably yield extremely inaccurate results by the above method. In such cases introduce 4 grams of the material, or an amount of a uniform solution equivalent to this amount of the dry substance, into a Rohrig tube or similar apparatus, make up to a volume of 10 cc. with water, add 1.25 cc. of concentrated ammonium hydroxid and mix thoroughly. Add 10 cc. of 95% alco- hol and mix. Then add 25 cc. of washed ether and shake vigorously for half a min- ute; then add 25 cc. of petroleum ether (b. p. below 60°C.), and shake again for half a minute. Allow to stand for 20 minutes or until the separation between the 132 METHODS OF ANALYSIS [Chap. liquids is complete. Draw off as much as possible of the ether-fat solution (usually 0.5-0.8 cc. will be left) into a weighed flask through a small, rapid filter. The flask should be weighed with a similar one as a counterpoise. Again extract the liquid remaining in the tube, this time with 15 cc. each of ether and petroleum ether, shake vigorously half a minute with each, and allow to settle. Proceed as above, wash- ing the tip of the spigot and the filter with a few cc. of a mixture of equal parts of the 2 ethers (previously mixed and free from deposited water). For absolutely exact results the extraction must be repeated. This third extraction usually yields not more than about 1 mg. of fat, if the previous ether-fat solutions have been drawn off closely, or an amount averaging about 0.02% on a 4 gram charge. Evapo- rate the ether slowly on a steam bath, then dry the fat in a boiling water oven until the loss in weight ceases. Test the purity of the fat by dissolving in a little petro- leum ether. Should a residue remain, wash the fat out completely with petroleum ether, dry the residue, weigh, and deduct the weight. 30 PARAFFIN IN CONFECTIONERY.-TENTATIVE. Add to the ether extract in the flask, as above obtained, 10 cc. of 95% alcohol and 2 cc. of sodium hydroxid solution (1 to 1), connect the flask with a reflux con- denser, and heat for an hour on the water bath, or until saponification is complete. Remove the condenser and allow the flask to remain on the bath until the alcohol is evaporated and the residue is dry. Dissolve the residue as completely as pos- sible in about 40 cc. of water and heat on the bath, shaking frequently. Wash into a separatory funnel, cool, and extract with 4 successive portions of petroleum ether, which are collected in a tared flask or capsule. Evaporate the petroleum ether and dry in the oven to constant weight. Any phytosterol or cholesterol present in the fat would be extracted with the paraffin. The amount is so insignificant that it may be disregarded generally. The character of the final residue should, however, be confirmed by determining its melting point, specific gravity, and refractive index. 31 ALCOHOL IN SmUPS USED IN CONFECTIONERY ("BRANDY DROPS").— TENTATIVE. Collect in a beaker the sirup from a sufficient number of pieces to yield 30-50 grams of sirup. Strain the sirup into a tared beaker and weigh. Introduce the sirup into a 250-300 cc. distilling flask, dilute with half its volume of water, attach the flask to a vertical condenser and distil almost 50 cc, or as much of the liquid as possible without causing charring. Foaming may be prevented by adding a little tannin, or a piece of paraffin about the size of a pea, to the contents of the distil- lation flask. Cool the distillate, make up to volume with water, mix well, and ascertain the specific gravity of the liquid by means of a pycnometer, and obtain the corresponding weight of alcohol in the 50 cc. of distillate from XVI, 5. Cal- culate the per cent by weight of alcohol in the candy filling. 32 COLORING MATTER.— TENTATIVE, Proceed as directed under XI. 33 METALS.— TENTATIVE. Proceed as directed under XII. IX] SACCHARINE PRODUCTS 133 HONEY." 34 PREPARATION OF SAMPLE.— TENTATIVE. (a) Liquid or strained honey. — If the sample is free from granulation, mix thor- oughly by stirring or shaking before drawing weighed portions for the analytical determination. If the honey is granulated, place the container, having the stopper loose, in a water bath, and heat at a temperature not exceeding 50°C. until the sugar crystals dissolve; mix thoroughly, cool, and weigh portions for the analytical de- terminations. If sediment such as particles of comb, wax, sticks, bees, etc., are present, heat the sample to 40°C. in a water bath and filter through cheese-cloth before weighing portions for analj'sis. (b) Comb honey.— Cut across the top of the comb, if sealed, and separate com- pletely from the comb by straining through a 40 mesh sieve. When portions of the comb or wax pass through the sieve, heat the sample as in (a) and strain through cloth. If the honey is granulated in the comb, heat until the wax is liquified, stir, cool, remove the wax and take the clear liquid for analysis. 35 MOISTURE. Weigh 2 grams of the sample into a tared, flat-bottomed aluminium dish, having a diameter of about 60 mm. and containing 10-15 grams of fine quartz sand, which has been previously washed, dried and ignited, and a small glass stirring rod; add 5-10 cc. of water and thoroughly incorporate with the sand and honey mixture by means of the rod; dry the dish and its contents to constant weight in a vacuum oven at a temperature not exceeding 70°C. 36 ASH.— OFFICIAL. Weigh 5-10 grams of honey into a platinum dish, add a few drops of pure olive oil to prevent spattering, and heat carefully until swelling ceases and then ignite at a temperature not above dull redness until a white ash is obtained. 37 SOLUBLE ASH.— TENTATIVE. Proceed as directed under 17. 38 ALKALINITY OF THE SOLUBLE ASH.-TENTATIVE. Proceed as directed under 18. POLARIZATION. 39 Direct Polarization. — Tentative. (a) Immediate direct polarization. — Transfer 26 grams of the honey to a 100 cc. flask with water, add 5 cc. of alumina cream, dilute to the mark with water at 20°C., filter, and polarize immediately in a 200 mm. tube. (b) Constant direct polarization. — Pour the solution from the tube used in read- ing (a) back into the flask, stopper, and allow to stand for 24 hours. At the end of this time again polarize the solution at 20°C. in a 200 mm. tube. (C) Birotation. — The difference between (a) and (b) gives the birotation. (d) Direct polarization at 87°C. — Polarize the solution, obtained in (b), at 87°C. in a jacketed 200 mm. tube. 134 METHODS OF ANALYSIS [Chap. 40 Invert Polarization. — Tentative. (a) At SO°C. — Invert 50 cc. of the solution obtained in 39 as directed under VIII, 14 or 16, and polarize at 20°C. in a 200 mm. tube. (b) At 87°C.— Polarize the solution, obtained as directed in (a), at 87°C. in a 200 mm. jacketed tube. 41 REDUCING SUGARS.-TENTATIVE. Dilute 10 cc. of the solution, used for direct polarization, 39, to 250 cc. and de- termine reducing sugars in 25 cc. of this solution by one of the methods given under VIII, 25, 36, 39 or 56, respectively. Calculate the result to per cent of invert sugar. 42 SUCROSE.— TENTATIVE. Proceed as directed under VIII, 18. Determine reducing sugars after inver- sion by diluting 10 cc. of the solution obtained in 40, with a small amount of water, neutralizing with sodium carbonate, and making up to 250 cc. with water. Employ 50 cc. of this solution for the determination, using the same method as in 41 . 43 LEVULOSE.-TENTATIVE. Multiply the direct reading at 87°C., 39 (d), by 1.0315 and subtract the product from the constant direct polarization at 20°C., 39 (b): divide the difference by 2.3919 to obtain the grams of levulose in a normal weight of the honey. From this figure calculate the per cent of levulose in the original sample. 44 DEXTROSE.— TENTATIVE. Subtract the per cent of levulose, obtained in 43, from the per cent of invert sugar, found in 41 , to obtain the approximate per cent of dextrose. The dextrose can be determined more accurately by multiplying the per cent of levulose, as found in 43, by the factor 0.915, which gives its dextrose equivalent in copper reducing power. Subtract this figure from that of the reducing sugars, 41 , calculated as dextrose, to obtain the percentage of dextrose in the sample. (Owing to the difference in the reducing powers of different sugars, the sum of the dex- trose thus found and the levulose as obtained in 43 will be greater than the amount of invert sugar obtained in 41). 45 DEXTRIN (APPROXIMATE).-TENTATIVE. Transfer 8 grams of the sample (4 grams in the case of dark colored honey-dew honey) to a 100 cc. flask (using not more than 4 cc. of water) by allowing the sam- ple to drain from the weighing dish into the flask and then dissolving the residue in 2 cc. of water. After adding this solution to the contents of the flask, rinse the weighing dish with two 1 cc. portions of water to which a little alcohol is added sub- sequently. Fill the flask to the mark with absolute alcohol, shaking constantly. Set the flask aside until the dextrin has collected on the sides and bottom and the liquid is clear. Decant the clear liquid through a filter paper and wash the resi- due in the flask with 10 cc. of 95% alcohol, pouring the washings through the same filter. Dissolve the dextrin in the fiask with boiling water and filter through the filter paper already used, receiving the filtrate in a tared dish, prepared as directed under 4. Rinse the flask and wash the filter a number of times with small portions of hot water, evaporate on a water bath and dry to constant weight in vacuo at 70°C. IXJ SACCHARINE PRODUCTS 135 After determining the weight of the alcohol precipitate, dissolve the latter in water and make up to definite volume, using 50 cc. of water for each 0.5 gram of pre- cipitate or part thereof. Determine reducing sugars in the solution both before and after inversion as directed under VIII, 18, expressing the results as invert sugar. Calculate sucrose from the results thus obtained and subtract the sum of the reducing sugars before inversion and sucrose from the weight of the total alcoholic precipitate to obtain the weight of the dextrin. 46 FREE ACID.-TENTATIVE. Dissolve 10 grams of the honey in water and titrate with N/10 sodium hydroxid using phenolphthalein as an indicator. Express the results in terms of cc.of N/10 sodium hydroxid required to neutralize 100 grams of the sample. 47 GLUCOSE.-TENTATIVE. Qualitative test. — Dilute the honey with water in the proportion of 1 to 1, then add a tew cc. of iodin solution (1 gram of iodin, 3 grams of potassium iodid, 50 cc. of water). In the presence of glucose the solution turns red or violet, the depth and character of the color depending upon the quality and nature of the glucose em- ployed. A blank test with a pure honey of about the same color should be made in order to secure an accurate color comparison. Should the honey be dark and the percentage of glucose very small, precipitate the dextrin which may be pres- ent by adding several volumes of 95% alcohol. Allow to stand until the precipitate settles (do not filter), decant the liquid, dissolve the residue of dextrins in hot water, cool and apply the above test to this solution. A negative result is not proof of the absence of glucose as some glucose, especially of high conversion, does not give any reaction with iodin. ^ Quantitative test. — An approximate determination can be made by Browne's formula as follows: Multiply the difference in the polarizations of the invert solu- tion at 20°C. and 87°C. by 77 and divide this product by the percentage of invert sugar after inversion found in the sample. Multiply the quotient by 100 and di- vide the product by 26.7, to obtain the percentage of honey in the sample; 100 per cent minus the per cent of honey gives the percentage of glucose. COMMERCIAL INVERT SUGAR.io QUALITATIVE TESTS. Fiehe Test {Bryan Modification"). — Tentative. 48 REAGENT. Resorcin solution. — Dissolve 1 gram of resorcin in 100 cc. of hydrochloric acid, sp. gr. 1.19. 49 MANIPULATION. Introduce 10 cc. of a 50% honey solution into a test tube and add 5 cc. of ether. Shake gently and allow to stand for some time until the ether layer is clear. Trans- fer 2 cc. of this clear ether solution to a small test tube and add a large drop of the resorcin solution. Shake and note the color immediately. In the presence of arti- ficial invert sugar, the resorcin assumes immediately an orange-red color turning to dark red. 136 METHODS OF ANALYSIS [Chap. Feder Anilin Chlorid Test.^"^ — Tentative. 50 REAGENT. Anilin chlorid solution. — To 100 cc. of C. P. anilin add 30 cc. of 25% hydrochloric acid. 51 MANIPULATION. Introduce 5 grams of the honey into a porcelain dish and add 2.5 cc. of the anilin reagent. A bright red color indicates the presence of commercial invert sugar. 52 DIASTASE." Mix 1 part of honey with 2 parts of sterile water. Treat 10 cc. of this solution with 1 cc. of 1% soluble starch solution and digest at 45°C. for an hour. At the end of this time test the mixture with 1 cc. of iodin solution (1 gram of iodin, 2 grams of potassium iodid, 300 cc. of water). Treat another 10 cc. portion of the honey solution, mixed with 1 cc. of the soluble starch solution, without heating to 45°C., with the reagent and compare the colors produced. If the original honey had not been heated sufficiently to kill the diastase, an olive-green or brown coloration will be produced in the mixture that has been heated at 45°C. Heated or artificial honey becomes blue. MAPLE PRODUCTS. 53 PREPARATION OF SAMPLE.— TENTATIVE. (a) Maple sirup. — Determine the moisture by the method given under 54 (a). If the moisture is less than 35%, and there is some mineral sediment, pour the clear sirup into a beaker, washing the sediment also into the beaker with water. Then concentrate the sirup by boiling to a moisture content of about 35% (b. p. 104°C.). Set aside until cool, or preferably let the covered material stand overnight, and pour off the clear liquid for the analytical work. Where no sediment is present the sample is ready for analysis after careful mixing. Where sugar has crystal- lized out, warm to dissolve the sugar before starting the analysis. It is desira- ble in order to compare results upon different samples, to reduce all results other than moisture to a dry substance basis as determined in the clear sirup. (b) Maple sugar, maple cream, maple wax, etc. — Determine moisture, by the meth- od given under 54 (b), in the sample in its original condition by thoroughly mixing, if semi-plastic, or by rubbing up in a mortar representative portions of the product if solid. For all other analytical determinations use a solution prepared as fol- lows: Weigh roughly 100 grams of the product into a beaker and dissolve by boil- ing with 200 cc. of water. Decant the resulting sirup while hot through a muslin filter, concentrate by boiling to a moisture content of 35% (b. p. 104°C.), cool, or preferably let the covered material stand overnight, set aside until clear, and use this clear sirup for analysis. It is desirable, in order to compare results upon different samples, that all results except moisture be expressed upon a dry basis. 54 MOISTURE.— TENTATIVE. (a) Maple sirup. — Proceed as directed under 35 or 10. (b) Maple sugar, maple cream, etc. — Proceed as directed under 35. 55 POLARIZATION.-TENTATIVE. (a) Direct at 20°C. — Proceed as directed under VIII, 14. (b) Invert at ;20°C.— Proceed as directed under VIII, 14. (C) Invert at 87°C. — Proceed as directed under 25 to detect commercial glucose. IX] SACCHARINE PRODUCTS 137 53 REDUCING SUGARS AS INVERT SUGAR.-TENTATIVE. (a) Before inversion. — Proceed as directed under VIII, 25, using an aliquot of the solution used for direct polarization, 55 (a), and only neutral lead acetate for clarification. (b) After inversion. — Proceed as directed under VIII, 25, using an aliquot of the solution used for the invert polarization, 55 (b), and only neutral lead acetate for clarification. SUCROSE. 57 Bij Polarization. — Tentative. Proceed as directed under VIII, 14 or 16. 58 By Reducing Sugars Before and After Inversion. — Tentative. Proceed as directed under VIII, 18. 59 TOTAL ASH.— TENTATIVE. Proceed as directed under 13. 80 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE. Proceed as directed under 17. 61 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE. Proceed as directed under 18. 62 ALKALINITY OF THE INSOLUBLE ASH.— TENTATIVE. Proceed as directed under 19. LEAD NUMBER (WINTON).— TENTATIVE. 63 REAGENTS. Standard basic lead acetate solution. — Boil 430 grams of normal lead acetate and 130 grams of litharge, for 30 minutes, or boil 560 grams of Home's dry basic lead acetate with 1 liter of water, cool, allow to settle and dilute the supernatant liquid to 1.25 sp. gr. To a measured amount of this solution add 4 volumes of water and filter if not perfectly clear. The solution should be standardized each time a set of determinations is made. If the directions for preparing the basic lead acetate are not carried out care- fully, the use of Home's dry basic lead acetate is preferable. 64 DETERMINATION OF LEAD IN THE BLANK. Transfer 25 cc. of the standard basic lead acetate to a 100 cc. flask, add a few drops of acetic acid, and make up to the mark with water. Shake and determine lead sulphate in 10 cc. of the solution as directed under 65. The use of the acid is im- perative in this case to keep the lead in solution, when diluted with water. 65 DETERMINATION. Transfer 25 grams of the sample to a 100 cc. flask by means of water. Add 25 cc. of the standard basic lead acetate and shake, fill to the mark, shake, and allow to stand for at least 3 hours before filtering. Pipette 10 cc. of the clear filtrate into a 250 cc. beaker, add 40 cc. of water and 1 cc. of concentrated sulphuric acid, shake and add 100 cc. of 95% alcohol. Allow to stand overnight, filter on a tared Gooch, 138 METHODS OF ANALYSIS [Chap. wash with 95% alcohol, dry in a water oven, and ignite in a muffle or over a Bun- sen burner, applying the heat gradually at first, and avoiding a reducing flame. Cool and weigh. Subtract the weight of lead sulphate so found from the weight of lead sulphate found in the blank, 64, and multiply by the factor 27.325. The use of this factor gives the lead number directly without the various calculations other- wise required. * MALIC-ACID VALUE. 66 Cowles Melhod.^^ — Tentative. Weigh 6.7 grams of the sample into a 200 cc. beaker, add 5 cc. of water, then 2 cc. of a 10% calcium acetate solution and stir. Add gradually, and with constant stirring, 100 cc. of 95% alcohol, and agitate the solution until the precipitate set- tles, or let stand, until the supernatant liquid is clear. Filter off the precipitate and wash with 75 cc. of 85% alcohol. Dry the filter paper and ignite in a platinum dish. Add 10 cc. of N/10 hydrochloric acid and warm gently until all the lime dissolves. Cool and titrate back with N/10 sodium hydroxid, using methyl orange as an indicator. The difference in cc. divided by 10 represents the malic acid value of the sample. Previous to use the reagents should be tested by a blank determina- tion and any necessary corrections applied. 67 METALS.— TENTATIVE. Proceed as directed under XII. SUGAR HOUSE PRODUCTS. SUCROSE IN BEETS. 68 Alcohol Extraction Method {Herzfeld Modification^^). — Tentative. Weigh 26 grams of the beet pulp and transfer to a 100 cc. flask with about 50 cc. of 90% alcohol and 3-5 cc. of basic lead acetate solution. Connect a reflux condenser to the flask and place on a boiling water bath for 10-15 minutes. Then pour the whole into a Soxhlet extractor, washing out the flask with fresh portions of 90% alcohol. Connect the same 100 cc. flask to the extractor, and fit the latter with a return condenser. Add 90% alcohol until the siphon is started and the flask is about three fourths full. Place the flask in a covered water bath kept at a heat that will allow the alcohol to boil freely. Continue the extraction for .1-4 hours, or until a test of the alcohol in the extractor gives no color withalpha-naphthol solution when tested as follows: Introduce into a test tube a few drops of the alco- hol coming from the extractor, add 4 or 5 drops of a 20% alcoholic alpha-naphthol solution and 2 cc. of water. Shake well, tip the tube, and allow 2-5 cc. of colorless concentrated sulphuric acid to flow down the side of the tube; then hold the tube upright and, if sucrose is present, a color varying from a faint to a deep violet will be noted at the junction of the two liquids. On shaking, the whole solution becomes a blue violet color. This test is suitable for this work, but it must be remembered that other substances besides sucrose give this color reaction. Remove the flask, transfer to a 100 cc. graduated flask, cool to the standard temperature, dilute to the mark with 90% alcohol, shake and filter, keeping the funnel covered with a watch glass. Polarize in a 200 mm. tube. Avoid evaporation and changes of temperature and also use a minimum amount of basic acetate for clarification, 3 cc. rather than 5 cc. By digesting the beet pulp with the alcohol before extraction, the time of extraction is gieUly shortened the pulp becomes thoroughly impregnated with the alcohol, and all the air is re- moved, resulting in a good extraction of the whole material. If the pulp is fine IX] SACCHARINE PRODUCTS 139 and tends to clog the siphon, alcohol-washed cotton may be used as a plug in the extractor before adding the beet pulp, and a fine mesh screen may be placed over the pulp to keep the whole compact in the extractor. 69 Pellet Aqueous Method^* (Hot Digestion). — Tentative. Weigh 52 grams of the beet cuttings and transfer them with water to a wide- mouthed flask graduated to a content of 201.2 cc; add 5-10 cc. of basic lead acetate solution, fill the flask to the mark with hot water, and shake. Immerse the flask in a water bath at 80°C. and rotate at intervals. Add water from time to time so that at the end of the heating (about 30 minutes) the water in the flask is a little above the mark. Remove the flask from the water bath and allow it to cool to standard temperature. Add sufficient concentrated acetic acid to make the solu- tion very slightly acid (generally less than 0.5 cc.) and a few drops of ether to break the foam. Make up to the mark, mix thoroughly, filter, and polarize in a 200 mm. tube. The fineness of the pulp governs the time of heating. Add enough water at the start and maintain this volume during the extraction, so that not more than 5 cc. of water will be necessary to complete the volume after cooling. The proportion of pulp to water must not be increased beyond the prescribed amount, for when smaller proportionsof water to pulp are used and then a large quantity of water is added at the last to make up to volume, the sugar does not become equally diffused and the results are too low. Differences of over 1% in sugar content may be caused by lack of care in this particular. 70 Hot Water Digestion Method. — Tentative. (Herzfeld Modification of the Sachs Le Docte Method'^) There are needed nickel-plated sheet iron vessels, 11 cm. high, 6 cm. body diame- ter, and 4 cm. mouth diameter, also stoppers covered with tin foil to fit the same. Weigh 26 grams of the beet pulp on a watch glass (small enough to go into the neck of the beaker) and transfer to the metal beaker, add 177 cc. of dilute basic lead acetate solution (5 parts of basic lead acetate solution (sp. gr. 1.25) to 100 parts of water), shake and stopper lightly. Submerge the beaker in a water bath at 75°-80°C. for 30 minutes, shaking intermittently. When all the air has been expelled (generally after 5 minutes), tighten the stopper. After 30 minutes, shake, cool to standard temperature, filter, add a drop of acetic acid to the filtrate and polarize in a 400 mm. tube. The reading is the per cent of sugar in the beet pulp. BIBLIOGRAPHY. 1 Browne. Handbook of Sugar Analysis. 1912, p. 16. ' Wiss. Abh. der Kaiserlichen Normal-Eichungs-Kommission, 1900, 2: 153; U. S. Bur. Standards, Circ. 19, 5th ed., p. 26. » Intern. Sugar J., 10: 69; U. S. Bur. Chem. Bull. 122, p. 169. * Z. anal. Chem., 1899, 38: 345. * Leach. Food Inspection and Analysis. 1913, p. 624. « Analyst, 1890, 21: 182. ^ Leach. P'ood Inspection and Analysis. 1913, p. 622. 8 U. S. Bur. Chem. Bulls. 110 and 154; Z. Nahr. Genussm., 1909, 18: 625. 9 U. S. Bur. Chem. Bull. 110, p. 60. loibid., 110 and 154. " Ibid., 154, p. 15. 12 Analyst, 1911, 36:586. " Z. Nahr. Genussm., 1910, 19: 72. >* J. Am. Chem. Soc, 190S. 30: 1285. " U. S. Bur. Chem. Bull. 146, p. 17. '6 Ibid., p. 18. 1' Ibid., p. 19. X. FOOD PRESERVATIVES.— TENTATIVE. SALICYLIC ACID. 1 PREPARATION OF SAMPLE. (a) Non-alcoholic liquids. — Many liquids may be extracted directly as described in 2 or 4 without further treatment. If gums or mucilaginous substances are present, pipette 100 cc. into a 250 cc. volumetric flask, add about 5 grams of sodium chlorid, shake until the latter is dissolved, make up to the mark with alcohol, shake vigor- ously, allow the mixture to stand for 10 minutes with occasional shaking, filter through a dry folded filter and treat an aliquot of the filtrate as directed under (b). (b) Alcoholic liquids. — Make 200 cc. of the sample alkaline with sodium hydroxid solution, using litmus as an indicator, and evaporate on a steam bath to about one third its original volume. Dilute to the original volume with water and filter, if necessary, through a dry filter. (C) Solid or semi-solid substances. — Grind the sample and mix thoroughly. Trans- fer a convenient quantity (50-200 grams according to the consistency of the sam- ple) to a 500 cc. volumetric flask, add sufficient water to make a volume of about 400 cc, shake until the mixture becomes uniform, add 2-5 grams of calcium chlorid, shake until the latter is dissolved, render distinctly alkaline with sodium hydroxid solution, using litmus as an indicator, fill to the mark with water, shake thoroughly, allow to stand for at least 2 hours shaking frequently and filter through a large folded filter. DETECTION AND ESTIMATION. 2 Ferric Chlorid Test. — Qualitative. Introduce 50 cc. of the sample or an equivalent amount of an aqueous extract, prepared as directed under 1 , into a separatory funnel, add one tenth its volume of dilute hydrochloric acid (1 to 3) and extract with 50 cc. of ether. If the mixture emulsifies, add 10-15 cc. of petroleum ether (b. p. below 60°C.) and shake. If this treatment fails to break the emulsion whirl the mixture in a centrifuge, or allow it to stand until a considerable portion of the aqueous layer has separated, run off the latter, shake vigorously and again allow to separate. Wash the ether layer with two 5 cc. portions of water, evaporate the greater portion of the ether in a por- celain dish on a steam bath, allow the remainder to evaporate spontaneously and add a drop of 0.5% ferric chlorid solution. A violet color indicates salicylic acid. If coloring matter or other interfering substances are present in the residue left after evaporation of the ether, purify the salicylic acid by one of the following methods: (a) Dissolve the residue from the ether extract, obtained as directed above, in about 25 cc. of ether, transfer the latter to a separatory funnel and shake with an equal quantity of water, made distinctly alkaline with several drops of am- monium hydroxid. Allow to separate, filter the aqueous laj'er through a wet fil- ter into a porcelain dish, evaporate almost to dryness, and test the residue as directed above. (b) Drj' the residue from the ether extract, obtained as directed above, in a desiccator over sulphuric acid and extract with several 10 cc. portions of carbon 141 142 METHODS OF ANALYSIS [Chap. disulphid or petroleum ether (b. p. below 60°C.), rubbing the contents of the dish with a glass rod, and filtering the successive portions of the solvent through a dry paper into a second porcelain dish. Evaporate the greater portion of the solvent on a steam bath, allow the remainder to evaporate spontaneously and test the residue as directed above. (C) Transfer the residue from the ether extract, obtained as directed above, to a small porcelain crucible by means of a few cc. of ether and allow the solvent to evaporate spontaneously. Cut a hole in a piece of asbestos board sufficiently large to admit about two thirds of the crucible, cover the latter with a small, round- bottomed flask filled with cold water, and heat over a small Bunsen flame until any salicylic acid present has sublimed and condensed upon the bottom of the flask. Test the sublimate as directed above. 3 Jorissen's Test.^ — Qualitative. Dissolve the residue from the ether extract, obtained as directed under 2, or, in case impurities are present, the purified material obtained as directed under 2 (a), (b) or (C) in a little hot water. Cool 10 cc. of the solution in a test tube, add 4 or 5 drops of 10% potassium nitrite solution, 4 or 5 drops of 50% acetic acid and 1 drop of 10% cupric sulphate solution, mix thoroughly and heat to boiling. Boil for half a minute and allow to stand for 1-2 minutes. In the presence of salicylic acid a blood red color will develop. Colorimetric Method. — Quantitative. 4 EXTRACTION. Pipette a convenient portion of the sample (100 cc. or a volume representing not less than 20 grams of the original sample) or a solution, prepared as in 1 , into a sepa- ratory funnel, make the solution neutral to litmus with dilute hydrochloric acid (1 to 3) and add an excess of concentrated hydrochloric acid equivalent to 2 cc. of acid for each 100 cc. of solution. Extract with 4 separate portions of ether, using for each extraction a volume of ether equivalent to half the volume of the aqueous layer. If an emulsion forms on shaking, this may usually be broken by adding a little (one fifth the volume of the ether layer) petroleum ether (b. p. be- low 60°C.) and shaking again or by centrifugalizing. If an emulsion still persists, allow it to remain with the aqueous layer. If an emulsion remains after the fourth extraction, separate it from the clear ether and the clear aqueous layer and extract it separately with 2-3 small portions of ether. Combine the ether extracts, wash with one tenth their volume of water, allow the layers to separate and reject the aqueous layer. Wash in this way until the aqueous layer after sepa- ration yields a yellow color upon the addition of methyl orange and 2 drops of N/10 sodium hydroxid. Distil slowly the greater part of the ether, transfer the remainder to a jjorcelain dish and allow the ether to evaporate spontaneously. If there are no interfering substances present, proceed as directed in 5. If such interfering substances are present, purify the residue by one of the following methods: (a) Dry thoroughly the residue in vacuo over sulphuric acid and extract with 10 portions of 10-15 cc. each of carbon disulphid or petroleum ether (b. p. below 60°C.), rub the contents of the dish with a glass rod and filter the successive portions of the solvent through a dry filter into a porcelain dish. Test the extracted resi- due with a drop of ferric alum solution and, if it gives a reaction for salicylic acid, dissolve it in water and reextract with ether, proceeding as directed above. Dis- til the greater portion of the carbon disulphid or petroleum ether and allow the remainder to evaporate spontaneously. Proceed as directed in 5. X] FOOD PRESERVATIVES 143 (b) Dissolve the residue in 40-50 cc. of ether. Transfer the ether solution to a separatory funnel and extract with 3 successive 15 cc. portions of 1% ammonium hydroxid. (If fat is known to be present in the original ether e.xtract, extract the latter directly with 4 portions of the ammonium hydroxid instead of 3.) Combine the alkaline aqueous extracts, acidify, again extract with ether and wash the com- bined ether extracts as directed above. Distil slowly the greater portion of the ether, allow the remainder to evaporate spontaneously and proceed as directed in 5. 5 DETERMINATION. Dissolve the residue, obtained in 4, in a small amount of hot water and, after cooling, dilute to a definite volume (usually 50-100 cc), dependent on the amount of salicylic acid present. If the solution is not clear, filter through a dry filter. Dilute aliquots of the solution and treat with a few drops of 0.5% ferric chlorid solution or 2% ferric alum solution. The ferric alum solution should be boiled until a precipitate appears, allowed to settle, and filtered. The acidity of the solution is slightly increased in this manner, but it remains clear for a considerable time, and the turbidity caused by its dilution with water is much less and does not appear as soon as when the unboiled solution is used. This turbidity interferes with the exact matching of the color. Compare the colors developed with that obtained when a standard salicylic acid solution (containing 1 mg. of salicylic acid in 50 cc.) is similarly treated, using Nessler tubes or a colorimeter. In either case, and especially with ferric chlorid, avoid an excess of the reagent, although an excess of 0.5 cc. of 2% ferric alum solu- tion may be added to 50 cc. of the comparison solution of salicylic acid without impairing the results. BENZOIC ACID. PREPARATION OF SAMPLE. 6 General Method. If solid or semi-solid, grind the sample, and mix thoroughly. Transfer about 150 grams to a 500 cc. graduated flask, add enough pulverized sodium chlorid to saturate the water in the sample, render alkaline with sodium hj^droxid solution or milk of lime, and dilute to the mark with a saturated salt solution. Allow to stand for at least 2 hours, with frequent shaking, and filter. If the sample contains large amounts of matter precipitable by salt solution, it is advisable to follow a method similar to that given under 7 (d). When alcohol is present, follow the method given under 7 (C). When large amounts of fats are present, make an alkaline extraction of the filtrate before proceeding as directed under 1 1 . 7 Special Methods. (a) Ketchup. — Saturate the water in 150 grams of ketchup by adding 15 grams of pulverized sodium chlorid. Transfer the mixture to a 500 cc. graduated flask, rins- ing with about 150 cc. of saturated sodium chlorid solution. Make slightly alkaline to litmus paper with strong sodium hydroxid solution and fill to the mark with satu- rated salt solution. Allow to stand for at least 1 hours, shaking frequently. Squeeze through a heavy muslin bag and then filter through a large folded filter. (b) Jellies, jams, preserves and marjnalades. — Dissolve 150 grams of the sam- ple in about 300 cc. of saturated salt solution. Add 15 grams of pulverized sodium chlorid. Make alkaline to litmus paper with milk of lime. Transfer to a 500 cc. graduated flask and dilute to the mark with saturated salt solution. Allow to 144 METHODS OF ANALYSIS [Chap. stand for at least 2 hours, shaking frequently, centrifugalize if necessary, and filter through a large folded filter. (C) Cider containing alcohol, and similar products. — Make 250 cc. of the sample alkaline to litmus paper with sodium hydroxid solution and evaporate on the steam bath to about 100 cc. Transfer the sample to a 250 cc. graduated flask, add 30 grams of pulverized sodium chlorid and shake until dissolved. Dilute to the original volume, 250 cc, with saturated salt solution, allow to stand for at least 2 hours, shaking frequently, and filter through a folded filter. (d) Salted or dried fish. — Wash 50 grams of the ground sample into a 500 cc. gradu- ated flask with water. Make slightly alkaline to litmus paper with strong sodium hydroxid solution and dilute to the mark with water. Allow to stand for at least 2 hours, shaking frequently, and then filter through a folded filter. Pipette accu- rately as large a portion of the filtrate as possible (at least 300 cc.) into a second 500 cc. flask. Add 30 grams of the pulverized sodium chlorid for each 100 cc. of solution. Shake until the salt has dissolved and dilute to the mark with saturated salt solution. Mix thoroughly and filter off the precipitated protein matter on a folded filter. 8 DETECTION AND ESTIMATION. Extract benzoic acid as directed under 2 or 4. If benzoic acid is present in considerable quantity, it will crystallize from the ether in shining leaflets having a characteristic odor on heating. Dissolve the residue in hot water, divide into 2 portions, and test according to 9 or 10. 9 Ferric Chlorid Test. — Qualitative. Make the solution from 8 alkaline with ammonium hydroxid, expel the excess of ammonia by evaporation, dissolve the residue in water, and add a few drops of a neutral 0.5% ferric chlorid solution. A brownish precipitate of ferric benzoate indicates the presence of benzoic acid. 10 Modified Mohler Test.^ — Qualitative. Add to the water solution, prepared as described under 8, 1-3 cc. of N/3 sodium hydroxid and evaporate to dryness. To the residue, add 5-10 drops of concentrated sulphuric acid and a small cr3^stal of potassium nitrate. Heat for 10 minutes in a glycerol bath at 120°-130°C., or for 20 minutes in a boiling water bath. The temperature must not exceed 130°C. After cooling add 1 cc. of water and make distinctly ammoniacal; boil the solution to decompose any ammonium nitrite which may have been formed. Cool and add a drop of fresh, colorless ammonium sulphid, without allowing the layers to mix. A red-brown ring indicates benzoic acid. On mixing, the color diffuses through the whole liquid and, on heating, finally changes to greenish yellow. This differentiates benzoic acid from salicylic acid or cinnamic acid. The last two form colored compounds, which are not destroyed by heating. The presence of phenolphthalein interferes with this test. 11 Quantitative Method. Pipette a convenient portion (100-200 cc.) of the filtrate, obtained in 6 or 7, into a separatory funnel. Neutralize the solution to litmus paper with hydrochloric acid (1 to 3) and add an excess of 5 cc. of the same acid. In the case of salted fish a precipitation of protein matter usually occurs on acidifying, but the precipitate does not interfere with the extraction. Extract carefully with chloroform, using successive portions of 70, 50, 40, and 30 cc. To avoid an emulsion, shake cautiously X] FOOD PRESERVATIVES 145 each time. The chloroform layer usually separates readily after standing a few minutes. If an emulsion forms, break it: (1) by stirring the chloroform layer with a glass rod; (2) by drawing it off into a second fimnel and giving 1 or 2 sharp shakes from one end of the funnel to the other; or (3) by centrifugalizing for a few moments. As this is a progressive extraction, draw off carefully as much of the clear chloro- form solution as possible after each extraction, but do not draw off any of the emul- sion with the chloroform layer. If this precaution is taken, the chloroform extract need not be washed. Transfer the combined chloroform extracts to a porcelain evaporating dish, rinse the container several times with a few cc. of chloroform, and evaporate to dryness at room temperature in a current of air dried over calcium chlorid. The extract may also be transferred from the separator^ funnel to a 300 cc. Erlen- meyer flask, rinsing the separatory funnel 3 times with 5-10 cc. of chloroform. Dis- til very carefully to about one fourth the original volume, keeping the temperature down so that the chloroform comes over in drops, not in a steady stream. Then transfer the residue to a porcelain evaporating dish, rinsing the flask 3 times with 5-10 cc. portions of chloroform, and allow to evaporate to dryness spontaneously. Dry the residue overnight (or until no odor of acetic acid can be detected if the product is a ketchup) in a desiccator containing sulphuric acid. Dissolve the resi- due of benzoic acid in 30-50 cc. of neutral alcohol, add about one fourth this volume of water, 1 or 2 drops of phenolphthalein, and titrate with N/20 sodium hydroxid (1 cc. is equivalent to 0.0072 gram of anhydrous sodium benzoate). SACCHARIN. 12 Qualilative Test. Extract with ether (after maceration and exhaustion with water, if necessary), as directed in 1 and 4. Allow the ether extract to evaporate spontaneously and note the taste of the residue. The presence of saccharin, to the extent of 20 mg. per liter, is indicated by a sweet taste. Confirm by heating with sodium hydroxid, as described below, and detecting the salicylic acid formed thereby. A sweet taste, suggesting the presence of a trare of saccharin, has been obtained frequently in saccharin-free wines, due to the so-called "false saccharin". Acidify 50 cc. of a liquid food or the aqueous extract of 50 grams of a solid or semi- solid, prepared as directed in 1 (C), and extract with ether as directed in 13. Dis- solve the residue, remaining after evaporation of the ether, in a little hot water and test a small portion of this solution for salicylic acid as directed under 2 or 3. Dilute the remainder of the solution to about 10 cc, and add 2 cc. of sulphuric acid (1 to 3). Heat to boiling and add a slight excess of 5% potassium perman- ganate solution, drop by drop; partly cool the solution, dissolve a piece of sodium hydroxid in it, and filter the mixture into a silver dish (silver crucible lids are well adapted to the purpose); evaporate to dryness and heat for 20 minutes at 210"- 215°C. Dissolve the residue in water, acidify with hydrochloric acid and test the ether extract for salicylic acid as directed under 2 or 3. By this method all the so-called "false saccharin" and the salicylic acid naturally present (also added salicylic acid when not present in too large an amount) are destroyed, while 5 mg. of saccharin per liter are detected with certainty. 13 Quantilalive Method. Pipette 100 cc. of the sample, or a convenient portion of a solution, prepared as directed under 1 , representing not less than 20 grams of the sample, into a sepa- 146 METHODS OF ANALYSIS [Chap. ratory funnel, make the solution neutral to litmus with dilute hydrochloric acid (1 to 3) and then add concentrated hydrochloric acid in the proportion of 5 cc. for each 100 cc. of solution. Extract with 4 separate portions of ether using, for each extraction, a volume of ether equivalent to half the volume of the aqueous layer. If the mixture emulsifies on shaking, this difficulty may be overcome as directed under 4. Wash the combined ether extracts with two 5 cc. portions of water, re- move the ether by distillation, and transfer the residue into a platinum crucible by means of a small amount of ether. Evaporate the ether on a steam bath, add about 2-3 cc. of 10% sodium carbonate solution to the residue, rotate so that all of the residue is brought into contact with the solution, and evaporate to dryness on a steam bath. Add 4 grams of a mixture of equal parts of anhydrous sodium and potassium carbonates, heat gently at first, and then to complete fusion for 30 minutes over an alcohol or other sulphur-free flame. Cool, dissolve the melt in water, acidify with hydrochloric acid and determine the sulphate present as barium sulphate. Correct the result thus obtained for any sulphur present in the fusion mixture as found in a blank determination. Calculate the amount of saccharin in the sample by multiplying the weight of barium sulphate by 0.7845. BORIC ACID AND BORATES. 14 Qualitative Test.^ Preliminary test. — Immerse a strip of turmeric paper in the sample acidified with hydrochloric acid in the proportion of 7 cc. of concentrated acid to each 100 cc. of sample, and allow the paper to dry spontaneously. If borax or boric acid is present, the paper will acquire a peculiar red color, changed by ammonium hydroxid to a dark blue-green but restored by acid. Solid or pasty samples may be heated with enough water to make them sufficiently fluid, concentrated hydrochloric acid added in about the proportion of 1 to 13 and the liquid tested in the same way. Confirmatory test. — Make about 25 grams of the sample decidedly alkaline with lime water and evaporate to dryness on a water bath. Ignite the residue to de- stroy organic matter. Digest with about 15 cc. of water, add concentrated hydro- chloric acid, drop by drop, until the ignited residue is dissolved, and then add 1 cc. in excess. Saturate a piece of turmeric paper with the solution, and allow it to dry without the aid of heat. In the presence of borax or boric acid, the color change will be the same as given above. 15 Quantitative Method.* Make 10-100 grams of the sample (depending upon the nature of the sample and the amount of boric acid present) distinctly alkaline with sodium hydroxid solution and evaporate to dryness in a platinum dish. Ignite the residue until organic matter is destroyed, avoiding an intense red heat, cool, digest with about 20 cc. of hot water, and add hydrochloric acid, drop by drop, until the reaction is distinctly acid. Filter into a 100 cc. flask, and wash with a little hot water, the volume of the filtrate not to exceed 50-60 cc. Return the filter containing any unburned carbon to the platinum dish, make alkaline by wetting thoroughly with lime water, dry on a steam bath and ignite to a white ash. Dissolve the ash in a few cc. of dilute hydrochloric acid and add to the liquid in the 100 cc. flask, rins- ing the dish with a few cc. of water. To the combined solutions, add 0.5 gram of calcium chlorid and a few drops of phenolphthalein, then 10% sodium hydroxid solution until a permanent light pink color is produced, and finally dilute to X] FOOD PRESERVATIVES 147 the mark with lime water. Mix and filter through a dry filter. To 50 cc. of the filtrate add N/1 sulphuric acid until the pink color disappears, then add methyl orange, and continue the addition of the acid until the yellow color is changed to pink. Boil for about 1 minute to expel carbon dioxid. Cool, and carefully add N/5 sodium hydroxid until the liquid assumes a yellow tinge, avoiding an excess of the alkali. All the boric acid is now in a free state with no uncombined sulphuric acid present. Add a little phenolphthalein, and an equal volume of neutral glycerol. Titrate with N/5 sodium hydroxid until a permanent pink color is produced. About 10 grams of mannitol may be substituted for the glycerol in this determination. At the end of the titration add an additional 2 grams and continue the titration if the pink color is discharged. Repeat the alternate addition of mannitol and alkali until a permanent end point is reached. One cc. of N/5 sodium hydroxid is equivalent to 0.0124 gram of boric acid. FORMALDEHYDE. 16 PREPARATION OF SAMPLE. If solid or semi-solid, macerate 200-300 grams of the material with about 100 cc. of water in a mortar. Transfer to a short-necked, 500-800 cc. copper or glass dis- tillation flask and make distinctly acid with phosphoric acid, connect with a con- denser and distil 40-50 cc. In the case of highly colored liquids, the same method of preparation should be employed. In the case of meats and fats, extract the formaldehyde with alcohol and use the filtrate. In the case of fat, heat the mixture above the melting point of the fat to insure thorough extraction. In the case of milk, shake with an equal volume of strong alcohol and use the filtrate. Shake other liquids with an equal volume of strong alcohol and filter from any insoluble matter. QUALITATIVE TESTS. 17 Phenylhydrazin Hydrochlorid Method.^ Mix 5 cc. of the distillate, as prepared under 16, or of an alcoholic solution or extract obtained as directed above, with 0.03 gram of phenylhydrazin hydrochlorid, and 4 or 5 drops of a 1% ferric chlorid solution. Add slowly and with agitation, in a bath of cold water to prevent heating the liquid, 1-2 cc. of concentrated sul- phuric acid. Dissolve the precipitate by the addition either of concentrated sul- phuric acid (keeping the mixture cool) or alcohol. In the presence of formaldehyde a red color develops. This method gives reliable reactions for formaldehyde in solutions of formalde- hyde varying from 1 part in 50,000 to 1 part in 150,000. Acetaldehyde and benz- aldehyde give no reaction when treated by this method and do not interfere with the reaction given by formaldehyde. 18 II ehner Method.^ Mix about 5 cc. of the distillate, obtained in 16, with an equal volume of pure milk, or a 1-2% solution of egg albumen, in a test tube and underlay with strong commercial sulphuric acid without mixing. A violet or blue color at the junction of the two liquids indicates formaldehyde. This color is given only in the presence of a trace of ferric chlorid or other oxidizing agent. As pointed out by Hehner, milk may be treated directJy by this method and gives positive tests in the presence of 1 or more parts of formaldehyde per 10,000. Some other articles of food rich in proteins, for example, egg albumen, give the reaction in the presence of water without the addition of milk. 148 METHODS OF ANALYSIS [Chap. 1 9 Leach Method. Mix about 5 cc. of the distillate, obtained under 16, with an equal volume of pure milk in a porcelain casserole and add about 10 cc. of concentrated hydrochloric acid, containing 1 cc. of 10% ferric chlorid solution, to each 500 cc. of acid. Heat to 80°-90°C. directly over the gas flame, rotating the casserole to break up the curd. A violet coloration indicates formaldehyde. Rimini Method.'' 20 Phenylhydrazin Hydrochlorid and Sodium Nitro-prussid Test. This method may be applied directly to liquid foods, to an aqueous or alcoholic extract of solid foods, or to the distillate prepared as directed in 16. In the case of milk, apply the method directly. In the case of meat, comminute the sample, extract with 2 volumes of hot water, and employ the expressed liquid for the test. Heat fats above their melting point with 10 cc. of alcohol, shake thoroughly, cool, filter through a moistened filter, and use the filtrate for the test. Dissolve a lump of phenylhydrazin hydrochlorid about the size of a pea in 3-5 cc. of the liquid to be tested, add 2-4 drops (not more) of a 5-10% sodium nitro- prussid solution and 8-12 drops of an approximately 12% sodium hydroxid solution. If formaldehyde is present, a green or blue color develops depending upon the amount. When formaldehyde is present to the extent of more than 1 part in 70,000- 80,000 in the solution tested, a distinct green or bluish green reaction is obtained. In more dilute solutions the green tint becomes less marked and a yellow tinge tend- ing toward greenish brown develops. With this method acetaldehyde and benzaldehyde give a color varying from red to brown, according to the strength of the solution. A reaction may there- fore be obtained with these aldehydes similar to that obtained with formaldehyde in solutions more dilute than 1 part in 70,033. The presence of acetaldehyde or benzaldehyde together with formaldehyde gives a yellowish or yellowish green tinge. The reaction for formaldehyde may therefore be masked by the presence of other aldehydes, but is characteristic when a clear green color is obtained. 21 Phenylhydrazin Hydrochlorid and Potassium Ferricyanid Test. Proceed as directed in 20, substituting a solution of potassium ferricyanid for the sodium nitro-prussid. Formaldehyde gives a red color. Alcoholic extracts from foods must be diluted with water to prevent the precipitation of potassium ferricyanid. The test is not applicable in the presence of the coloring matter of blood. 22 Phenylhrjdrazin Hydrochlorid and Ferric Chlorid Test. Treat 15 cc. of milk or other liquid food or of the distillate, prepared as directed under 16, with 1 cc. of a dilute phenylhydrazin hydrochlorid solution, then with a few drops of dilute ferric chlorid solution and, finally, with concentrated hydro- chloric acid. The presence of formaldehyde is indicated by the formation of a red color, which changes after some time to orange yellow. Milk may be examined directly by this method, but more delicate tests may be obtained from the distillate from milk or from milk serum. Acetaldehyde or benz- aldehyde does not interfere with the reaction. X] FOOD PRESERVATIVES 149 23 Phloroglucol Method.^ To 10 cc. of milk or other liquid food under examination in a test tube add, by means of a pipette, 2 cc. of phloroglucol reagent (1 gram of phloroglucol, 20 grams of sodium hydroxid and water to make 100 cc), placing the end of the pipette on the bottom of the tube in such a manner that the reagent will form a separate layer. If formaldehyde be present, a bright red coloration (not purple) forms at the zone of contact. This solution gives a yellow color in the presence of some alde- hydes, and, if it is used for the detection of aldehyde formed by the oxidation of methyl alcohol after the destruction of ethyl aldehyde with hydrogen peroxid, an orange yellow color will slowly appear when an insufficient amount of hydrogen peroxid has been employed. On the other hand, if the excess of hydrogen peroxid is not fully destroyed before the use of this reagent, a purple color develops slowly. The clear, red color given by the use of this reagent forms quickly, and, in the presence of but a small amount of formaldehyde fades rapidly. FLUORIDS. QUALITATIVE TESTS. 24 Method I. —Modified Method of Blarez.^ Thoroughly mix the sample and boil 150 cc. (in the case of solid foods an aqueous extract may be employed provided the fluorids are in a soluble form). Add to the boiling liquid 5 cc. of 10% potassium sulphate solution and 10 cc. of 10% barium acetate solution. Collect the precipitate in a compact mass (a centrifuge may be used advantageously) and wash upon a small filter. Transfer to a platinum crucible and ignite. Dip a carefully cleaned glass plate, while hot, in a mixture of equal parts of Car- naiiba wax and paraffin and allow to cool. Make, with a sharp instrument, a dis- tinctive mark through the wax, taking care not to scratch the surface of the glass. Add a few drops of concentrated sulphuric acid to the residue in the crucible and cover with the waxed plate, having the mark nearly over the center and mak- ing sure that the edge of the crucible is in close contact with it. Keep the top sur- face of the plate cool by means of a suitable device and heat the crucible for an hour at as high a temperature as practicable without melting the wax (an electric stove gives the most satisfactory form of heat). If fluorids be present, a distinct etching will be apparent on the glass where it was exposed. 25 Method II. The preceding method may be varied by mixing a small amount of precipitated silica with the precipitated barium fluorid and applying the method for the detection of fluosilicates, under 27 or 28. This method is of value in the case of foods whose ash contains a considerable amount of silica. Under these circumstances, concentrated sulphuric acid liber- ates silicon fluorid, which would escape detection under 24. FLUOBORATES AND FLUOSILICATES. 26 PREPARATION OF SAMPLE. Make about 200 grams of the sample alkaline with lime water, evaporate to dry- ness, and incinerate. Extract the crude ash with water, to which sufficient acetic 150 METHODS OF ANALYSIS [Chap. acid has been added to decompose carbonates, filter, ignite the insoluble portion, extract with dilute acetic acid, and again filter. The insoluble portion now con- tains calcium silicate and fluorid, while the filtrate will contain all the boric acid present. QUALITATIVE TESTS. 27 Method 7.1° Incinerate the filter, from 26, containing the insoluble portion, mix with a little precipitated silica, transfer to a short test tube, attached to a small U-tube contain- ing a few drops of water and add 1-2 cc. of concentrated sulphuric acid. Keep the test tube in a beaker of water on the steam bath for 30-40 minutes. If any fluorin be present, the silicon fluorid generated will be decomposed by the water in the U-tube and will form a gelatinous deposit on the walls of the tube. Next test the filtrate as directed under 14. If both hydrofluoric and boric acids be present, it is probable that they are combined as borofluorid. If, however, silicon fluorid is detected and not boric acid, the operation should be repeated with- out the introduction of the silica, in which case the formation of the silicon skeleton is conclusive evidence of the presence of fluosilicate. In an ash containing an ap- preciable amount of silica, sulphuric acid will liberate silicon fluorid rather than hydrofluoric acid. The presence of a fluosilicate is indicated, therefore, and not the presence of a fluorid. 28 Method II. Incinerate the filter, from 26, containing the insoluble portion, in a platinum crucible, mix with a little precipitated silica, and add 1 cc. of concentrated sul- phuric acid. Cover the crucible with a watch glass, from the underside of which a drop of water is suspended, and heat for an hour at 70°-80°C., keeping the watch glass cooled. The silicon fluorid which is formed is decomposed by the water, leav- ing a gelatinous deposit of silica and etching a ring at the periphery of the drop of water. Test the filtrate for boric acid as directed under 14. SULPHUROUS ACID. 29 Qualitative Test.^^ Add some sulphur-free zinc, and several cc. of hydrochloric acid to about 25 grams of the sample (with the addition of water, if necessary) in a 200 cc. Erlen- meyer flask. In the presence of sulphites, hydrogen sulphid will be generated and may be detected with lead acetate paper. Traces of metallic sulphids are occasionally present in vegetables, and will give the same reaction as sulphites under the conditions of the above test. Positive results obtained by this method should be verified by the distillation method under 30. It is always advisable to make the quantitative determination of sulphites, owing to the danger that the test may be due to traces of sulphids. A trace is not to be considered sufficient indication of the presence of sulphur dioxid either as a bleaching agent or as a preservative. TOTAL SULPHUROUS ACID. 30 Method I. — Distillation Method. Distil 20-100 grams of the sample (adding recently boiled water if necessary) in a current of carbon dioxid, after the addition of about 5 cc. of a 20% glacial phos- X] FOOD PRESERVATIVES 151 phoric acid solution, until 150 cc. have passed over. Collect the distillate in about 100 cc. of nearly saturated bromin water, allowing the end of the condenser to dip below the surface. The method and apparatus may be simplified without material loss in accuracy by omitting the current of carbon dioxid, adding 10 cc. of phosphoric acid instead of 5 cc, and dropping into the distillation flask, immediately before attaching the condenser, a piece of sodium bicarbonate weighing not more than 1 gram. The carbon dioxid liberated is not sufficient to expel the air entirely from the apparatus, but will prevent oxidation to a large extent. When the distillation is finished, boil off the excess of bromin, dilute the solution to about 250 cc, add 5 cc. of hydrochloric acid (1 to 3), heat to boiling, and precipitate the sulphuric acid with 10% barium chlorid solution. Boil for a few minutes longer, allow to stand overnight in a warm place, filter on a weighed Gooch, wash with hot water, ignite at a dull red heat, and weigh as barium sulphate. 31 Method II.— Direct Titration Method. In the examination of wine, fairly accurate results may be obtained by the fol- lowing method : Place 25 cc. of 5.6% potassium hydroxid solution in a 200 cc. flask. Introduce 50 cc. of the sample, mix with the potassium hydroxid solution, and allow the mix- ture to stand for 15 minutes with occasional agitation. Add 10 cc. of sulphuric acid (1 to 3) and a few cc. of starch solution, and titrate the mixture with N/50 iodin solu- tion. Introduce the iodin solution as rapidly as possible and continue the addition until the blue color persists for several minutes. One cc. of N/50 iodin is equiva- lent to 0.00064 gram of sulphur dioxid. DETERMINATION OF FREE SULPHUROUS ACID, 32 (Especially Adapted to Wine.) Treat 50 cc. of the sample in a 200 cc. flask with about 5 cc. of sulphuric acid (1 to 3) add about 0.5 gram of sodium carbonate to expel the air, and titrate the sul- phurous acid with N/50 iodin, as directed under 31. BETA-NAPHTHOL. 33 Qualitative Test. Extract 200 cc. of the sample, or of its aqueous extract, prepared as directed under 1 (C), with 10 cc of chloroform in a separatory funnel. To the chloroform extract in a test tube add a few drops of alcoholic potash, and place in a boiling water bath for 2 minutes. The presence of beta-napthol is indicated by the forma- tion of a deep blue color, which changes to green and then to yellow. ABRASTOL. QUALITATIVE TESTS. 34 Sinibaldi Method.^* Make 50 cc. of the sample alkaline with a few drops of ammonium hydroxid and extract with 10 cc. of amyl alcohol, adding ethyl alcohol if an emulsion is formed. Decant the amyl alcohol, filter if turbid, and evaporate to dryness. Add to the residue 2 cc. of nitric acid (1 to 1), heat on the water bath until half of the liquid is evaporated, and transfer to a test tube with the addition of 1 cc. of water. Add about 0.2 gram of ferrous sulphate and an excess of ammonium hydroxid, drop by 152 METHODS OF ANALYSIS [Chap. drop, with constant shaking. If the resultant precipitate is of a reddish color, dissolve it in a few drops of sulphuric acid, and add ferrous sulphate and ammonium hydroxid as before. As soon as a dark colored or greenish precipitate is obtained, introduce 5 cc. of alcohol, dissolve the precipitate in sulphuric acid, shake well and filter. In the absence of abrastol this method gives a colorless or light yellow liquid, while a red color is produced in the presence of 0.01 gram of abrastol. 35 Sangle-Ferriere Method." Boil 200 cc. of the sample with 8 cc. of concentrated hydrochloric acid for an hour in a flask fitted with a reflux condenser. Abrastol is thus converted into beta- naphthol and is detected as directed under 33. SUCROL OR DULCIN. QUALITATIVE TESTS. 36 M or pur go Method.^* Evaporate about 100 cc. of the sample, or of the aqueous extract prepared as directed under 1 (C) and neutralized with acetic acid, to a sirupy consistency after the addition of about 5 grams of lead carbonate, and extract the residue several times with 90% alcohol. Evaporate the alcoholic extract to dryness, extract the residue with ether, and allow the ether to evaporate spontaneously in a porcelain dish. Add 2 or 3 drops each of phenol and concentrated sulphuric acid and heat for about 5 minutes on the water bath, cool, transfer to a test tube and overlay with ammonium hydroxid or sodium hydroxid solution with the least possible mixing. The presence of dulcin is indicated by the formation of a blue color at the zone of contact. 37 Jorissen Method.^^ Suspend the residue from the ether extract obtained as directed above in about 5 cc. of water; add 2-4 cc. of an approximately 10% solution of mercuric nitrate, and heat for 5-10 minutes on the water bath. In the presence of sucrol a violet blue color is formed, which is changed to a deep violet on the addition of lead peroxid. FORMIC ACID. Quantitative Method. ^^ 38 REAGENTS. (a) Sodium acetate solution.— Dissolve 50 grams of dry sodium acetate in sufl5- cient water to make 100 cc. and filter. (b) Mercuric chlorid reagent. — Dissolve 100 grams of mercuric chlorid and 150 grams of sodium chlorid in sufficient water to make 1 liter and filter. (C) Tartaric acid. (d) Barium carbonate. 39 APPARATUS. The apparatus required (Fig. 6) consists of a steam generator (S), a 300 cc. flask (A) in which the sample is placed, a 500 cc. flask {B), containing a suspension of bari- um carbonate, a spray trap (T), a condenser, and a 1 liter graduated flask (C). The tip of the tube (D), leading into (fi), consists of a bulb containing a number of small holes to break the vapor into small bubbles. X] FOOD PRESERVATIVES 153 FIG. 6. APPARATUS FOR DETECTION OF FORMIC ACID. 40 DETERMINATION. For thin liquids like fruit juices, use 50 cc. For heavy liquids and semi-solids like sirups and jams, use 50 grams diluted with 50 cc. of water. Place the sam- ple in the flask (A), add 1 gram of tartaric acid, and connect as shown in Fig. 6, the flask (B) having been charged previously with a suspension of 2 grams of barium carbonate in 100 cc. of water. If much acetic acid is present, suflficient barium carbonate must be used so that at least 1 gram remains at the end of the operation. Heat the contents of flasks (.1) and (B) to boiling and distil with steam from the generator (5), the vapor passing first through the sample in flask {A), then through the boiling suspension of barium carbonate in (B), after which it is condensed, and measured in the graduated flask (C). Continue the distillation until 1 liter of dis- tillate is collected, maintaining the volume of the liquids in the flasks {A) and (B) as nearly constant as possible by heating with small Bunsen flames, and avoid- ing charring of the sample in the flask {A). After 1 liter of distillate has been col- lected, disconnect the apparatus and filter the contents of flask (B) while hot, wash- ing the barium carbonate with a little hot water. The filtrate and washings should now measure about 150 cc. If not they should be boiled down to that volume. Then add 10 cc. of the sodium acetate, 2 cc. of 10% hydrochloric acid, and 25 cc. of the mercuric chlorid reagent. Mix thoroughly and immerse the container in a boil- ing water bath or steam bath for 2 hours. Then filter on a tared Gooch, wash the precipitate thoroughly with cold water and finally with a little alcohol. Dry in a boiling water oven for 30 minutes, cool, weigh, and calculate the weight of formic acid present by multiplying the weight of the precipitate by 0.0975. If the weight of mercurous chlorid obtained exceeds 1.5 grams, the determination must be re- peated, using more mercuric chlorid reagent or a smaller amount of sample. A blank 154 METHODS OF ANALYSIS test should be conducted with each new lot of reagents employed in the reduction, using 150 cc. of water, 1 cc. of 10% barium chlorid solution, 2 cc. of 10% hydrochloric acid, 10 cc. of the sodium acetate, and 25 cc. of the mercuric chlorid reagent, heat- ing the mixture in a boiling water bath or steam bath for 2 hours. The weight of mercurous chlorid obtained in this blank test must be deducted from that obtained in the regular determination. BIBLIOGRAPHY. 1 J. Ind. Eng. Chem., 1910, 2: 24. 2 Z. Nahr. Genussm., 1910, 19: 137; C. A., 1910, 4: 1523. 3 U. S. Div. Chem. Bull. 51, p. 113. * Sutton. Volumetric Analysis. 10th ed., 1911, p. 95. 6 Z. Nahr. Genussm., 1902, 5: 353. 6 Analyst, 1895, 20: 155. 7 Ann. di farmacoterapia e chim., 1898, 27: 97; Chem. Zentr., 1898, (1), 1152; 1902, (1), 1076; J. Soc. Chem. Ind., 1898, 17: 697; Chem. Ztg., 1902, 26: 246; Abs. J. Chem. Soc, 1902, 82: 367. * Service de Surveillance des Aliments en Belgique, through Bui. soc. chim. belg., 1897-8, 11-12: 211; Abs. Analyst, 1897, 22: 282. 9 Chem. News, 1905, 91: 39; Ann. Rept. Mass. State Board of Health, 1905, p. 498 i«Mon. Sci., 1895, (4), 9: 324. " U. S. Div. Chem. Bull. 13, (8), p. 1032. 12 Mon. Sci., 1893, (4), 7: 842. '3 Compt. rend., 1893, 117: 796. '* Z. anal. Chem., 1896, 35: 104 " Ibid., 628. '« Biochem. Z., 1913, 51: 253. XI. COLORING MATTERS IN FOODS.— TENTATIVE. (An italicized number, following immediately the name of a dye, is the number by which that dye is designated in "A Systematic Survey of the Organic Colouring Matters", 1904, by Arthur Green, based on the German of Schultz and Julius.) 1 PIGMENTS. The insoluble pigments, ultramarine, lampblack, etc., are most commonly used as facings and may be separated by washing the sample with water and allowing the washings to settle. The particles of coloring matter can be identified by micro- scopic examination and by treatment of the residue or purified coloring matter with chemical reagents. A large proportion of the common pigments other than lakes, such as the yellow, brown and red ochres and umbers, are derivatives of the heavy metals and contain iron, manganese, etc. Others, such as various green and blue compounds, including the green chlorophyll derivatives, contain copper. These pigments may be identified by the usual tests for the respective metals. The analytical properties of the insoluble coloring matters are described in various standard works, some of which are listed in the bibliography, especially "Farb- stofftabellen by Schultz'." Soluble Coloring Matters and Their Lakes, coal tar dyes. 2 Wool dyeing test^. (a) WiJies, fruit juices, distilled liquors, flavoring extracts, vinegars, beers, sirups, non-alcoholic beverages and similar products. — Dilute 20-200 cc. of the sample with 1-3 volumes of water and boil or heat on the steam bath with a small piece of white woolen cloth (nun's veiling). When the mixture contains much alcohol, heat until most of the alcohol has been removed; in other cases, take out the wool after 5-15 minutes and rinse with water. Then treat the liquid with 3 or 4 drops of con- centrated hydrochloric acid for each 100 cc. and warm again for 10-20 minutes with a clean piece of wool. The basic dyes go on the fiber best from neutral or faintly ammoniacal solutions and, if present, will appear on the first piece of wool. Acid colors dye from neutral solutions but more readily from those containing free acid. If the wool takes up any considerable amount of coloring matter in either case, the presence of coal tar dyes is indicated. The lichen colors' (Archil, Cudbear, Litmus) go readily on wool, however, and many other natural colors, such as Turmeric, will dye the fiber, if present in considerable amount. On the other hand, a few coal tar dyes, especially Auramine O and Naphthol Green B, are quite unstable and, if present in small amounts, may give no distinct dyeing. Acid dyes are much more frequently used than basic dyes and in most cases may be removed from wool with- out much decomposition by "stripping" the latter with dilute ammonia^ By the action of the alkali, many natural colors are destroyed, while others remain for the most part on the fiber. If the behavior with wool in neutral and acid solutions indicates the presence of acid dyes, rinse the colored cloth thoroughly with water, cover with 2% ammonium hydroxid solution in a casserole, boil for a few minutes, remove the cloth and squeeze out the adhering liquid. Boil the ammoniacal solu- 155 156 METHODS OF ANALYSIS [Chap. tion to remove the excess of ammonia, drop in a piece of clean, wet wool, make dis- tinctly but not strongly acid with hydrochloric acid and boil again. If acid coal tar dyes are present, they will usually give a fairly clean, bright dyeing on the second piece of wool. A further purification may be carried out by repeating the stripping and re-dyeing, though generally accompanied by corresponding loss of dye. (b) Candies and similar colored sugar products. — Dissolve about 20 grams of the sample in 100 cc. of water and treat the solution as directed under (a). When the coloring matter is on the surface of the candy, pour off the solution before the color- less inner portion has dissolved. (C) Jams and jellies. — Boil a mixture of 10-20 grams of the sample and 100 cc. of water with wool in neutral and also in acid solution as directed under (a). For thick jams it is usually better, though less easy, first to extract the coloring sub- stances by treating the product as directed under (d). (d) Canned and preserved fruits and vegetables, sausage casings, smoked fish, coffee, spices, etc. — Macerate 20-200 grams of the sample with 4-5 times its weight of 80% alcohol. After standing a few hours pour off the solvent as completely as possible and repeat the extraction, using 70% alcohol containing about 1% of ammonia. (1) Examine separately the filtered alcoholic extracts as directed under (a); or, (2) Boil the ammoniacal solution until practically neutral, complete the neutralization with acetic acid, add the neutral 80% alcohol extract, continue the evaporation until most of the alcohol is removed, and boil with wool as directed under (a). (e) Cocoa and chocolate products. — Treat cocoa as directed under (d). The alco- holic extract will contain a large amount of natural coloring matter and several dyeings and strippings may be necessary to get rid of this in order to show the pres- ence of coal tar dyes. Chocolate may be treated similarly but the following procedure is preferable: Wash 20-200 grams of the well divided sample with gasoline on a filter until most of the fat has been removed; if the gasoline is colored, reserve for the examination of oil-soluble dyes as directed under 3. Remove most of the adherent solvent from the residue by evaporation or pressure between layers of absorbent paper and digest with alcohol as directed under (d). Coal tar dyes may also be detected in chocolate and cocoa products by mixing directly with 3-4 times their weight of hot water and immediately boiling the magma with wool, as directed under (a). Because of the presence of large amounts of fatty and protein materials, this method is not very satisfactory. (f) Cereal products. — Proceed as directed under (d), in most cases working with a large amount of the sample, 200-500 grams, and a relatively smaller amount of alcohol. Where tests are to be made only for the acid dyes, the extraction with neutral 80% alcohol may be omitted advantageously. 3 OIL-SOLUBLE DYES\ Prepare an alcoholic solution of the oil-soluble dye by one of the following methods which are to be applied to the oil or fat obtained by extraction with ether or gasoline if the nature of the substance requires it : (a) Shake the oil or melted fat with an equal volrnne of 90% alcohol. The alcohol after separation will contain Aniline Yellow, Butter Yellow, Aminoazotoluene and Auramine, if present. (b) Saponify 20-200 grams of the oil or fat with alcoholic potash and, after re- moval of most of the alcohol on the steam bath, extract the soap with ether or gaso- line. Most of the common dyes are removed by this treatment, though the digestion with strong alkali may cause some decomposition and make the extraction rather troublesome. XIJ COLORING MATTERS IN FOODS 157 (C) Dilute 20-200 grams of the oil or melted fat with 1-2 volumes of gasoline and shake out successively with 2-4% potassium or sodium hydroxid solution, 12-15% hydrochloric acid, and phosphoric-sulphuric acid mixture, prepared by mixing 85% phosphoric acid with about 10-20% by volume of concentrated sulphuric acid. The dilute alkali extracts Sudan G and Annatto. The dilute hydrochloric acid extracts Aniline Yellow (7), Aminoazotoluene, and Butter Yellow {16), the first 2 forming orange-red, the latter cherry-red solutions in this solvent. Benzeneazo- beta-naphthylamin and homologues also come in this group, though they are not extracted very readily and decompose rapidly on standing in strongly acid solution. The phosphoric acid mixture is necessary for the extraction of Sudan I (11), Sudan II (49), Sudan III (14^), and the homologue of the last, Sudan IV. The procedure is not very suitable in the presence of Auramine but this dye is seldom found in oils. Neutralize the alkaline and dilute hydrochloric acid solutions; dilute the phosphoric acid mixture and partially neutralize, cooling the liquid during this operation; and extract the dyes by shaking with ether or gasoline. For the direct dyeing test use the alcoholic solution, obtained as directed in (a). Evaporate to dryness the ether or gasoline solutions, obtained as directed in (b) and (C), and dissolve the residue in 10-20 cc. of strong alcohol. To the alcoholic solution add some strands of white silk and a little water and evaporate on the steam bath until the alcohol has been removed or until the dye is taken up by the silk. The dyeing test is sometimes unsatisfactory and in all cases a small portion of the alcoholic solu- tion should be tested by treating with an equal volume of concentrated hydrochloric acid and stannous chlorid solution. The common oil-soluble coal tar dyes are ren- dered more red or blue by the acid and are decolorized by the reducing agent. Most of the natural coloring matters become slightly paler with the acid and are little changed by the stannous chlorid solution. Separation of Coloring Matters in Pure Condition by Means of Immiscible Solvents''. 4 preparation of sample. (a) Water-soluble colors. — Proceed as directed under 2, omitting the fixation of the color on wool, and obtain an aqueous solution as free as practicable from sus- pended matter, alcohol, acids, alkalies and salts. (b) Water-insoluble lakes. — If the sample is in solid form, treat the well divided material with sufficient water to form a paste. Liquids require no preparation except the removal of alcohol when present. 5 Mixtures of Orange I, Erythrosine, Indigo Carmine, Amaranth, Tartrazine, Naphthol Yellow S, Ponceau 3R and Light Green S F Yellowish. The use of immiscible solvents for the separation of mixtures of coloring matters usually involves a systematic fractionation since many of the dyes used do not differ very greatly in their solubilities in the various solvents. When it seems probable that only the 8 coal tar dyes permitted under the Federal Food and Drugs Act^ are present, the following abridged procedure may be used for their separation. For this procedure the concentration of the dye solution should lie preferably between 0.01-0.05%. The solutions obtained in the examination of colored food products practically never require further dilution but with commercial food colors care must be taken that the concentration is not too high. Treat the sample, prepared as directed in 4, with one half its volume of concentrated hydrochloric acid and extract a few times with amyl alcohol. The use of the centrifuge is sometimes necessary 158 METHODS OF ANALYSIS [Chap. to separate the layers. Designate the residual aqueous layer as A. Combine the amyl alcohol extracts and wash with 4-5 portions of N/4 hydrochloric acid or until this solvent extracts very little color. These washings will contain any Indigo Carmine, Amaranth and Tartrazine present, the Indigo Carmine being removed in somewhat larger proportion in the first washings than the other 2. With ordinary concentration very little Ponceau will be removed. Designate these combined washings as B. 6 ORANGE I AND ERYTHROSINE. Measure, if necessary, the amyl alcohol extract, under 5, then (1) Dilute with an equal volume of petroleum ether or low boiling gasoline, and again wash several times with N/4 hydrochloric acid to extract Ponceau 3R and Naphthol Yellow S; or, (2) Without dilution with gasoline, wash with 5% salt solution until these 2 dyes are extracted. Designate these washings as C. The Ponceau and Yellow having been removed, the amyl alcohol, containing an equal volume of gasoline, is washed a few times with water which will extract Orange I. This dye having been removed, shake the solution, although the latter may appear almost colorless, with very dilute sodium hydroxid solution to remove Erythrosine. If considerable Orange I is present, some of it may contaminate the washings containing the Ponceau 3R and Naphthol Yellow S, especially when these have been separated by means of N/4 hydrochloric acid after the addition of gasoline. 7 INDIGO CARMINE, AMARANTH AND TARTRAZINE. The presence of 2 or all 3 of these dyes is usually indicated by the appearance of the N/4 hydrochloric acid washings, B, under 5. Evaporate the combined N/4 hydrochloric acid washings to dryness to remove the excess of hydrochloric acid and dissolved amyl alcohol. Dissolve the residue in water, divide the solution and iden- tify the constituent colors in the portions. To a portion of the slightly acidified solution add a few decigrams of urea, warm and add 1 or 2 drops of sodium nitrite solution. Indigo Carmine is converted into the pale yellow isatin sulphonate while the other dyes are but little affected. The isatin compound is not ordinarily present in sufficient concentration to tint the solution but it differs from Tartrazine also in being much less readily extracted by amyl alcohol from strong acid solutions (less than one half from 4N acid). The solution now contains the Amaranth or Tar- trazine, or both, practically unaffected. Amaranth is much more quickly attacked by most reducing agents than Tartrazine. Treat the solution, which should be neu- tral or faintly acid (in the presence of sodium carbonate the reduction of the tar- trazine takes place still more slowly), at room temperature with a dilute solution of sodium hyposulphite (Na2S204), adding the latter very carefully, drop by drop, and allowing sufficient time after the addition of each drop for the reduction to take place. When the color shows that the Amaranth has been destroyed completely, shake the mixture at once with air to oxidize the slight excess of hyposulphite before it can react further on the Tartrazine. To separate the Indigo Carmine heat to boiling another portion of the solution, which should be neutral or faintly acid, and add dilute sodium hyposulphite solution, drop by drop, until all the dyes are reduced. On shaking with air the Indigo Carmine is quickly re-formed. 8 NAPHTHOL YELLOW S AND PONCEAU 3R. Treat the N/4 acid solution or the salt solution, C, under 6, as the case may be, containing the Ponceau and Naphthol Yellow S, with enough hydrochloric acid to make it about 2N and shake out a few times with washed ethyl acetate*. Remove XI] COLORING MATTERS IN FOODS 159 the Yellow from the combined ethyl acetate extracts by shaking with water. Naph- thol Yellow S is almost colorless in strongly acid solutions, and its absence in wash- ings, etc., must never be assumed until these have been made alkaline. Finally separate the Ponceau 3R from the acid solution by shaking with amyl alcohol, and then wash out the dye from this extract with a few small portions of water. If, in the case of mixtures containing Orange I, the washings of the ethyl acetate, which should contain only Naphthol Yellow S, become more red upon the addition of al- kalies, combine, then (1) Make N/4 with hydrochloric acid and remove the contami- nating Orange by shaking with amyl alcohol-gasoline mixture (1 to 1); or, (2) Treat the combined washings mth one fifth their volume of concentrated hydrochloric acid, extract the dyes by shaking once with amyl alcohol, and remove the Yellow by washing with several portions of 5% salt solution. 9 LIGHT GREEN S F YELLOWISH. The original mixture, A, under 5, from which the above mentioned 7 colors have been removed by adding acid and shaking out with amyl alcohol, may still contain Light Green S F Yellowish, which will be colorless or nearly so in the acid solution. To separate this dye treat the mixture with strong ammonia or potassium hydrox- id solution until slightly alkaline, and neutralize with acetic acid. Any Green present will now be apparent by the color of the mixture. Extract the color by shaking with a few small portions of dichlorhydrin. Wash the dichlorhydrin extract with a little water, then dilute with several volumes of benzene or carbon tetra- chlorid, and remove the dye by shaking with water. When coal tar dyes other than the 8 mentioned above are present, the solutions obtained in this procedure will be found to contain a coloring matter which does not correspond exactly in properties to one of the dyes named above. When coal tar dyes other than these 8 are present, reference should be made to the larger works'. Coal Tar Dyes in General. 10 basic dyes. Most basic dyes may be separated from mixtures by making alkaline with sodium hydroxid and shaking with ether'". Use the sample, prepared as in 4, for this pur- pose. Separate the ether layer, which may or may not be colored, and shake with 2-5% acetic acid, which will take up any dye present, forming a colored solution. Although the common basic colors undergo some alteration by this treatment", it may be used for the qualitative detection and separation of Methyl Violet B {4-51), Magenta {U8), Bismarck Brown (197), Malachite Green (427), and Rhodamine B (504). With care Auramine (425) may also be separated in this way though it is quickly decomposed on standing in alkaline solution. 11 ACID DYES. The following short procedure is often convenient for the examination of mixtures of acid dyes: Make the sample, prepared as in 4, the color concentration of which does not vary greatly from 0.01-0.05%, strongly acid by adding one half its volume of concentrated hydrochloric acid and shake with amyl alcohol. Separate the amyl alcohol solution and wash by shaking with successive portions of one half its volume of water, reserving the portions in separate test tubes or beakers. Because of the acid dissolved in the amyl alcohol these washings will show a regular decrease in acidity and the coloring matters will appear in maximum amount in the different fractions according to their respective solubilities. Ponceau 6R (108) is washed out chiefly while the acidity is still high, N/1 or above. Amaranth (107), Brilliant 160 METHODS OF ANALYSIS [Chap. Scarlet (106) and Tartrazinc (94) appear when the washings have an acidity between N/1 and N/4; Orange G (14) and Sohible Blue (480) between N/2 and N/16; Palatine Scarlet (53), Ponceau 2R (55) and 3R (56), Naphthol Yellow S (4), Cochineal (706), Crystal Ponceau (64) and Azorubine A (103) between N/IG and N/256. When the acid is practically all removed, Orange I (85), Orange II (86) and Croceine Orange (13) begin to wash out, and less readily. Orange IV (88) and Metanil Yellow (95). Finally the unsulphonated coloring matters, such as Erythrosine G (516), Erythrosine (517) and the Rose Bengals (520 and 523) are removed very slowly by water or not at all when all traces of acid have been removed. Acid Yellow (8) and Brilliant Yellow S (89) are not very uniform in composition. They are partially taken up by amyl alcohol from acid solution and appear chiefly in the first washings. Indigo Carmine (692) behaves somewhat similarly. Identification of the Coal Tar Dyesi^. 1 2 general. The most widely used tests for the identification of coal tar dyes refer to the changes produced with acids and alkalies. Other tests, based upon the behavior with reducing agents, followed perhaps by treatment with oxidants or by separation and identification of the reduction products^', and tests based upon oxidation of the dye and treatment of the oxidation products^^ are generally applicable. Spectro- scopic methods are also used^^. 13 COLOR CHANGES PRODUCED WITH ACIDS AND ALKALIES. Transfer the separated coloring matter to wool (or silk in the case of oil-soluble dyes) by boiling as directed in 2 (a) or 3. Care should be taken that the final dyeing is made in a solution fairly free from foreign matter such as sugar or aromatic sub- stances, which, adhering to the fiber, may modify the reaction. In most cases the amount of color available is small and should not be dyed on too large a piece of wool (or silk). Rinse thoroughly the dyed fibre in rmining water, dry, cut into small pieces and place separately in the depressions of a white porcelain spot plate. Moisten the pieces with the respective reagents employed. (For many coloring matters the hue upon treatment with acids or alkalies varies markedly with the concentration of the reagents and amount of dye present; therefore the unknown dye should be compared with dyeings of known colors of approximately the same dye concentration as shown by this appearance.) The table under 14 shows the color changes produced by concentrated hydro- chloric and sulphuric acids, 10% sodium hydroxid and 12% ammonium hydroxid solutions on wool dyed with 0.1-0.5% of the respective coloring matters. Included also are the reactions of the oil-soluble colors but these refer to dyeings on silk. The dyes are arranged approximately according to hue. Brown is classed with orange, black (gray) with violet. XI] COLORING MATTERS IN FOODS 161 14 Table 14. Color reactions produced on dyed fibers by various reagents. COLORING MATTER HYDROCHLORIC ACID SULPHURIC ACID SODIUM HYDROXID AMMONIUM HVOROXID Rhodamine B 501, Orange Yellow Bluer Bluer Rose Bengal 523 Almost decolorized Orange No change No change Archil 710 Red Dull brown Violet Violet Magenta US Yellowish brown Dull brown Decolorized Paler Acid Magenta m Almost decolorized Yellow Decolorized Decolorized Piilatine Red 62 Darker Violet Dull brown Little change Bordeaux B 65 Violet Blue Brown Little change Amaranth 107 Slightly Violet to Dull brown- Little change darker brownish ish Azorubine A ion Little change Violet Red Rod Erythrosine 517 Orange-yellow Orange-yellow No change No change Ponceau 6RB 169 Blue Blue Dull violet- red Brown Little change Ponceau 6R 108 Violet-red Violet Orange-red Crystal 64 Violet-red Violet Dull brown Little change Ponceau Ponceau 3R 56 Little change Little change Dull orange Little change Sudan III* US Violet, then brown Green Violet-red Little change Safranine 584 Greenish blue Green Red Red Brilliant 106 Red Violet-red Yellowish Orange-red Scarlet brown Ponceau 2R 55 Little change Little change Brownish j'Cllow No change Palatine 53 Darker Violet-red Brownish No change Scarlet yellow Ervthrosine G 516 Yellow-orange Yellow-orange No change No change Sudan 11* 49 Red Violet-red Little change No change Sudan 1* 11 Orange-red Red Redder No change Cochineal 706 Little change Little change Violet-red Violet-red Bismarck 197 Redder, Browner Yellower Yellower Brown darker Bismarck 201 Redder, Browner Yellower Yellower Brown R darker Orange I 85 Violet Violet Red, dark Red, dark Orange 11 86 Red Red Dull red No change Croccine 13 Orange-red Orange Slightly No change Orange darker Orange G 14 Little change Orange Dull, brown- ish red No change Orthotoluene- Red Violet Little change No change azo-beta- naphthyl- amine* Sudan G* 10 Orange-yellow Brownish yellow Orange-yellow No change Butter Yellow* 16 Violet-red Orange-yellow No change No change Aniline Yellow* 7 Brownish red Orange-yellow Little change No change Aminoazo- Dull orange Orange-yellow Little change No change ortho-tolu- ene* 162 METHODS OF ANALYSIS [Chap. 14 Table 14.— Continue d. COLORING MATTER HYDROCHLORIC ACID SULPHURIC ACID SODIUM HYDROXID AMMONIUM HYDROXID Fluoresceine 510 Little change Little change Green flu- orescent Green flu- orescent Meianil Yellow 95 Violet-red Violet No change No change Azoflavine 92 Violet-red Violet-red Dull brown Little change Acid Yellow 8 Red Orange Little change No change Brilliant 89 Violet-red Violet-red Little change Little change Yellow S Tartrazine 94 Slightly darker Slightly darker Little change Little change Naphthol 4 Almost Very pale, No change No change Yellow S decolorized dull brown Auramine 425 Decolorized Almost decolorized Decolorized Paler Turmeric 707 Red Reddish brown Orange Orange Quinoline 667 Slightly Brownish Slightly Little change Yellow darker yellow paler Naphthol 398 Yellowish Brownish No change No change Green B yellow Guinea Green 433 Pale orange- Pale, dull Decolorized Decolorized B yellow yellow Light Green S F 435 Pale orange- Pale, dull Decolorized Decolorized Yellowish yellow vellow Night Green 2B 438 Pale orange- yellow Pale, dull yellow Decolorized Paler Malachite 427 Almost Almost Decolorized Decolorized Green decolorized decolorized Erioglaucine A 436 Yellow Pale, dull yellow or brown Slightly darker Little change Patent Blue A 442 Pale orange- yellow Pale or dull brown Little change Little change Soluble Blu« 480 Paler Brown Pale reddish Almost decol- orized Indigo Carmine 692 Slightly Slightly Greenish yel- Greenish blue darker darker low Formyl Violet 468 Pale orange- vellow Pale, dull orange Decolorized Decolorized Methyl Violet B 451 Yellowish Yellowish Decolorized Almost decol- orized Nigrosine, sol- 602 Dull bluish Dull greenish Brownish red, Pale reddish uble paler 15 SPECIAL TESTS FOR COAL TAR DYES PERMITTED' UNDER THE FEDERAL FOOD AND DRUGS ACT. The dyes, given in 5, are sufficiently characterized in most cases by the solubilities shown in their separation and by the color changes given by acids and alkalies on the dyed fiber. This is especially true with Amaranth, Tartrazine, and Orange I. By treatment with reducing agents such as stannous chlorid, titanous chlorid, zinc dust or sodium hyposulphite in acid solution, Indigo Carmine, Amaranth, Tartra- zine, Ponceau 3R and Orange I are decolorized. With Indigo Carmine the color returns on shaking with air, most readily on warming, or on the addition of oxidiz- ing agents such as ferric chlorid or potassium persulphate. Excess of the reducing agents must of course be avoided. With the last 4 named dyes the color is not re- stored. Dilute solutions of Light Green S F Yellowish, Naphthol Yellow S and XI] COLORING MATTERS IN FOODS 163 Erythrosine become paler or colorless with acids so that the effects of acid reducing agents are not so readily apparent. Neutral solutions of Naphthol Yellow S are decolorized by sodium hyposulphite and other reducing agents, the color not return- ing with air or oxidants. An evanescent deepening of the shade may take place immediately upon the addition of the hyposulphite. Erythrosine and Light Green S F Yellowish become paler with sodium hyposulphite, the color being partially restored upon the addition of potassium persulphate. In hot solutions containing an excess of sodium tartrate the dyes named are readily decolorized by titanium trichlorid". In the case of Indigo Carmine if the reducing agent has been added carefully and an excess avoided, the blue color readily returns on shaking with air. With Erythrosine and Light Green S F Yel- lowish the color is scarcely restored by air but on cooling and adding potassium persulphate returns imperfectly. The reduction products of the other dyes do not give colored solutions again on oxidation disregarding a slight yellowish or brownish tint that may sometimes appear. Indigo Carmine is extracted in small proportions from slightly acid solutions by shaking with dichlorhydrin. Most of the other common bluish dyes are triphenyl- methane derivatives and are relatively more soluble in this liquid than in the aque- ous layer. A small portion (1 cc.) of the solution obtained in the separation, 5, may be used directly. Ponceau SR gives in neutral or faintly acid solutions a bluish red, flocculent pre- cipitate with barium chlorid or acetate, practically all of the dye being removed from solution. Some of the solution obtained in the separation, 5, may be used in this test, first neutralizing the free hydrochloric acid with sodium acetate; or better, it may be evaporated to dryness on the steam bath to remove the acid and the residue taken up with a little water. The solution should contain 0.005% or more of the dye. Naphthol Yellotv S, in solutions containing an excess of ammonia or sodium car- bonate, becomes intensely rose-red on the addition of sodium hyposulphite, the color gradually fading again as complete reduction takes place. Erythrosine differs from most of the common dyes by containing iodin. To test for this, acidify the solution with sulphuric acid, shake with ether, separate the ether solution of the color and evaporate to dryness in a platinum dish after the addition of a few drops of sodium carbonate solution or sufficient to form the deep red sodium salt. Hold the dish containing the residue in the Bunsen flame until organic matter is destroyed, take up the residue with water, acidify with sulphuric acid and test for iodin in one of the usual ways, such as with chlorin water and carbon disulphid or tetrachlorid, or with starch paste and an oxidizing agent. It is useless to test for iodin with very small amounts of dye but in most cases sufficient coloring matter can be separated from the food product to give satisfactory results. 16 Natural Coloring Matters. The natural coloring matters as a class show much less tendency to dye animal fiber than do the common synthetic colors. In many cases the crude products used contain a number of colored substances and a complete separation can scarcelj' be attempted. Most of the natural coloring matters, in dilute solution, are sensitive to alkalies, some to acids, hence such reagents must be used with care. 164 METHODS OF ANALYSIS [Chap. SEPARATION OF NATURAL COLORING MATTERS. 17 Exlraclion with Ether from Neutral Solutions. From neutral solutions ether extracts Carotin, Xanthophyll (the pigment found in leaves, fats and oils, egg yolk, carrots, etc.), the coloring matter of tomatoes and paprika and green Chlorophyll. The coloring matter remains in the ether solution on shaking with dilute sodium hydroxid solution or dilute hydrochloric acid, no apparent change taking place although chemically the substances may be altered more or less by this treatment. 18 Extraction with Ether from Acid Solutions, From slightly acid solutions ether extracts very readily and completely the coloring matter of Alkanet, Annatto, Turmeric, and the red dyewoods, Sandalwood, Camwood and Barwood. It extracts in large proportion the flavone coloring matters of Fustic, Persian Berries (after hydrolysis), and Quercitron as well as the coloring matter of Brazilwood and the green derivatives formed from Chlorophyll by alkaline treatment. It extracts in relatively small amount the coloring matters of Logwood, Archil, Saffron and Cochineal. The coloring matters of this group are readily re- moved from ether by shaking with alkaline solutions but in most cases rapidly undergo chemical change. 19 Extraction with Amijl Alcohol from Acid Solutions. From slightly acid solutions amyl alcohol extracts largely the coloring matters of Logwood, Archil, Saffron and Cochineal. [From ammoniacal Cochineal (Carmine) the ordinary coloring matter is readily re-formed upon standing with hydrochloric acid.] Amyl alcohol extracts in relatively small proportions Caramel and the Antho- cyans constituting the red coloring matter of the most common fruits. IDENTIFICATION OF NATURAL COLORING MATTERS. 20 REAGENTS. (a) Hydrochloric acid. — Sp. gr. L20. (b) 10% sodium or potassium hydroxid solution. (C) Sodium hyposulphite solution. — A freshly prepared 5% solution of "Blankite", sodium hyposulphite (Na2S204). (d) 0.6% ferric chlorid solution.— Freshly prepared but may be made by diluting a 10% stock solution. (e) 10%o potassium or ammonium alum, solution. (f ) 5% uranium or sodium uranium acetate solution (g) Sulphuric acid. — Sp. gr. L84. 21 PROCEDURE. Relatively few good tests are known for the common natural colors. Some of their most useful analytical properties'^ are tabulated in 22. In general these tests should be applied to the somewhat purified solutions of the coloring matter obtained as indicated in 17, 18 or 19. Evaporate ether solutions to dryness, warm the residue with a little alcohol and dilute the alcoholic solution with water. Apply the reagents as stated below: XI] COLORING MATTERS IN FOODS 165 Hydrochloric acid. — Add concentrated acid (sp. gr. 1.20) to the solution, first 1 or 2 drops, then a large excess, equal to 3-4 times the volume of the solution. Sodium hydroxid {-potassium hydroxid). — Make the solution slightly alkaline by adding a drop of the 10% sodium hydroxid solution. A 10% solution of potassium hydroxid in methyl alcohol must be used for the "brown phase reaction" for chloro- phyll, described in 23, and may also be employed for the other tests. Sodium hyposulphite. — Add the sodium hyposulphite solution drop by drop. Ferric chlorid. — Add a small amount of the 0.5% ferric chlorid solution to the solution to be tested. The reagent must be added very carefully, a small drop at a time, as the colorations are not obtained in all ca.ses when an excess is used. Alu7n. — Add to the test solution one fifth its volume of the 10% potassium or ammonium alum solution. Uranium acetate. — Add the 5% uranium acetate solution drop by drop to the solu- tion to be tested. Concentrated sulphuric acid on the dry color. — Evaporate a small amount of the solution or of the coloring matter in a porcelain dish. Cool thoroughly and treat the dry residue with 1 or 2 drops of cold, concentrated sulphuric acid. The color- ations are in some cases extremely fugitive and may be observed only the instant the acid wets the residue. The properties of pure preparations of the various natural coloring matters are described, for the most part, by Rupe*^. Properties of the Chlorophylls and Carotinoids are given by Willstiitter and StolP^. Those of the coloring matters of the Corn Flower, Rose, Pelargona Flower, Larkspur, Cranberry, Whortleberry and Purple Grape are described by Willstattcr^". 166 METHODS OF ANALYSIS [Chap. PI cl 03 O -dZ3 1^ § 5 i 3 > > 0 o '3 !> : lg "1 s i e S s o E .J g s 0 Rose-red (change rather slow) Rose-red (change rather slow) h Dark shades of violet, brown or black (the first hue of- ten evanes- cent) Dark shades of violet, brown or black (the first hue of- ten evanes- cent) S s Almost decol- orized, color returning imperfectly by reoxida- tion Anthrocyani- dins derived by hydroly- sis, almost completely decolorized Decolorized, color return- ing when shaken with air. Reac- tion more easily seen in alkaline solution i 1 i Violet to violet-blue Violet-red Change to green, dull blue or slate col- or, usually very quickly, becoming browner by oxidation Deep blue Blue g a Deep red with excess of acid Deep red with excess of acid o K S O i 1 1 I (Brazilwood, Sandalwood, Camwood and Barwood) Anthocyans of red fruit col- ors Alkanet 13 < I XIJ COLORING MATTERS IN FOODS 167 S Red Yellow to orange Blue Blue, reaction 3 Cl'O 'Ih o Somewhat browner Orange colora- tions Not affected Little change More strong- ly yellow; Fustic, de- veloping a green flu- orescence Little change Slightly darker No marked change Perhaps somewhat browner No marked change. Perhaps somewhat browner Olive-green or black colora- tions No marked change. Perhaps somewhat browner . 1 1 No marked change Little affected Little affected Little affected Little affected Little affected i 1 > Orange-brown Bright-yellow Remains yellow Little or no change "Brown phase re- action", 23 Little change or slightly deeper brown Little or no change Remains orange. Little change Orange^red or carmine-red on addition of several volumes o f concentrated acid Becomes in- tensely yel- low with 2-4 volumes of concentrated acid Little or no change Little change. Perhaps slightly paler More brownish Little or no change ^ C 3 " J c 3 c Turmeric (solu- tion in ether or alcohol characterized by pure yel- low color and light green fluorescence) Flavone colors of Fustic, Per- sian Berries, Quercitron, etc. Saffron 1 i 1 c ^ 1 1 2 C oJ o 168 METHODS OF ANALYSIS [Chap. Special Tests for Natural Coloring Matters. 23 chlorophyll. The "brown phase reaction"-' may be useful for the characterization of Chloro- phyll, when this has not been previously treated with alkalies. Treat the green ether or petroleum ether solution of the coloring matter with a small amount of 10% solution of potassium hydroxid in methyl alcohol. The color becomes brown, returning to green in a few minutes. annatto. 24 Leach Test"-. Pour on a moistened filter an alkaline solution of the color obtiined by shaking out the oil or melted and filtered fat with warm, dilute sodium hydroxid solution. If Annatto is present, the filter paper will absorb the color so that, when washed with a gentle stream of water, it will remain dyed a straw color. Dry the filter and add a drop of stannous chlorid solution. If the color turns pink the presence of Annatto is confirmed. 25 turmeric. Carry out the highly characteristic reaction of Curcumine (Turmeric) with boric acid as follows: Treat the aqueous or dilute alcoholic solution of the color with hydrochloric acid until the shade just begins to appear slightly orange. Divide the mixture into 2 parts and add some boric acid powder or crystals to 1 portion. A marked reddening will be quickly apparent, best seen by comparison with the portion to which the boric acid has not been added. The test may also be made by dipping a piece of filter paper in the alcoholic solution of the coloring matter, drying at 100°C., then moistening with a weak solution of boric acid to which a few drops of hydrochloric acid have been added. On drying again a cherry-red color will be developed. 26 COCHINEAL. When the presence of Cochineal is suspected, acidify the mixture with one third its volume of concentrated hydrochloric acid and shake with amyl alcohol. Wash the amyl alcohol solution of the coloring matter 2-4: times with equal volumes of water to remove hydrochloric acid, etc. Dilute the amyl alcohol with 1-2 volumes of gasoline and shake with a few small portions of water to remove the color. Sepa- rate the solution into 2 portions. To the first add, drop by drop, 5% uranium ace- tate solution, shaking thoroughly after each addition. In the presence of cochineal a characteristic emerald-green color is produced-^ The green coloration with uranium salts is not developed in the presence of much free acid. Therefore add a little sodium acetate before making this test or a correspondingly large amount of uranium acetate must be added. To the second portion add a drop or so of ammon- ium hydroxid, and, in the presence of Cochineal, a violet coloration results. This, however, is not so sensitive to small amounts as the first test and many fruit colors give tests hardly to be distinguished. As cochineal lakes very often contain tin, further examination for this metal should always be made when water-insoluble cochineal compounds appear to be present. XI] COLORING MATTERS IN FOODS 169 BIBLIOGRAPHY. ' Schultz. Farbstofftabellon. 5th German ed., 1911-14. 2Abs. Z. anal. Chem., 1885, 24: 625; 1889, 28: G39; Conn. Agr. Exp. Sta. Rept., 1899, fll), p. 130. 3 J.Am. Chem. Soc, 1905, 27: 25. 4 Abs. Z. anal. Chem., 1896, 35: 397. 5U. S. Bur. Chem. Bull. 65, p. 152; Ann. fals., 1910, 3: 293; U. S. Bur. Chem. Circs. 25 and 63; Abs. Chem. Zentr., 1898, (2), 943. ^ U. S. Bur. Chem. Circs. 25 and 63; Allen. Commercial Organic Analysis. 4th ed., 1909-14, 5; Leach. Food Inspection and Analysis. 3rd ed., 1913; Girard and Dupre. Analyse des Malieres Alimentaires et Recherches de leur Falsification. 1894; J. pharm. chim., 6th ser., 1901, 13: 175; U. S. Bur. Animal Industry Circ. 180. ' U. S. Dept. Agr., F. I. Ds. 76 and 164. 8 U. S. Bur. Chem. Bull. 162, p. 57. ^ Heumann. Die Anilinfarben und ihre Fabrikation. 1888-1906; Green. Sys- tematic Survey of the Organic Colouring Matters. 2nd ed., rev., 1904, based on the German of Schultz and Julius; Schultz. Farbstofftabellen. 5th German ed., 1911- 14; Allen. Commercial Organic Analysis. 4th ed., 1909-14, 5; MuUiken. Identifi- cation of Pure Organic Compounds. 1910, 3. 10 Abs. Z. anal. Chem., 1887, 26: 100; 1888, 27: 232. "Ber., 1913, 46: 2131; 1914, 47: 1881. 12 Abs. Z. anal. Chem., 1887, 26: 100; 1888, 27: 232; Chem. Ztg., 1898, 22: 4.37; U. S. Bur. Chem. Circ. 63; Green. The Identification of Dyestuffs on Animal Fibres. Rev. ed., 1913. 1' Ber., 1888, 21: 3471. " U. S. Bur. Chem. Circ. 114. i^Form^nek. Spektralanalytischer Nachweiss kunstlicher Organischer Farb- stoffe zum Gebrauche bei wissenschaftlichen und gewerblichen Untersuchungen. 1900; Formanek und Grandmougin. Untersuchung und Nachweiss Organischer Farbstoffe auf Spectroskopischem Wege. 2nd ed., 1908-13. 1^ Knecht and Hibbert. New Reduction Methods in Volumetric Analysis. 1910. 1' U. S. Bur. Chem. Circs. 25 and 63; Allen. Commercial Organic Analysis. 4th ed., 1909-14, 5; Leach. Food Inspection and Analysis. 3rd ed., 1913. 18 Rupe. Die Chemie der Natiirlichen Farbstoffe. 1900-09. 1' Willstatter and Stoll. LTntersuchungen liber Chlorophyll, Methoden und Ergebnisse. 1913. ^oSitz. preuss. Akad., 1914, 12: 402. " Ber. botan. Ges., 1896, 14: 16; Willstatter and Stoll. Untersuchungen Uber Chlorophyll, Methoden und Ergebnisse. 1913. -2 Leach. Food Inspection and Analysis. 3rd ed., 1913, p. 536. 2' Girard and Dupre. Analyse des Matieres Alimentaires et Re>cherches de leur Falsification. 1894. XII. METALS IN FOODS. ARSENIC^.— TENTATIVE. 1 REAGENTS. (a) Nitric and sulphuric acids, arsenic-free. — Specific gravities 1.42 and 1.S4, respectively. (b) Stdphuric acid (1 to 2). (C) Zinc, arsenic-free. — Stick zinc broken into pieces approximately 1 cm. in length. (d) Lead acetate paper. — Heavy filter paper soaked in 20% lead acetate solution, dried and cut into pieces about 4.5 by 16 cm. (e) Lead acetate cotton. — Absorbent cotton soaked in 5% lead acetate solution. (f) Mercuric bromid paper. — Cut heavy, close-textured drafting paper (similar to Whatman's cold pressed) into strips exactly 2.5 mm. wide and about 12 cm. long. Soak for an hour in a 5% solution of mercuric bromid in 95% alcohol, squeeze out the excess of solution and dry on glass rods. Cut off the ends of the strips before using. (g) 20% potassium iodid solution. (h) Stannous chlorid solution. — Forty grams of stannous chlorid crystals made up to 100 cc. with concentrated hydrochloric acid. (i) Standard arsenic solution. — Dissolve 1 gram of arsenious oxid in 25 cc. of 20% sodium hydroxid solution, neutralize with dilute sulphuric acid, add 10 cc. of the concentrated sulphuric acid and dilute to 1 liter with recently boiled water. One cc. of this solution contains 1 mg. of arsenious oxid (AS2O3). Dilute 20 cc. of this solution to 1 liter. Fifty cc. of the latter solution when diluted to 1 liter give a dilute standard solution containing 0.001 mg. of arsenious o.xid (AS2O3) per cc. which is used to prepare the standard stains. The dilute solu- tions must be freshly prepared immediatel}' before use. 2 APPAR.\TUS. Use a 2 ounce wide-mouthed bottle as a generator. Fit this by means of a per- forated rubber stopper with a glass tube, diameter 1 cm. and 6 cm. long, containing a piece of the lead acetate paper rolled into a cylinder. Connect this tube by means of a perforated rubber stopper with a similar tube filled with the lead acetate cotton, squeezed to remove excess of the solution. The cotton in all tubes used should be uniformly moist to obtain comparative stains. Connect the second tube by means of a perforated rubber stopper with a narrow glass tube, internal diameter 3 mm. and 12 cm. long, containing a strip of the mercuric bromid paper. See Fig. 7. Rubber stoppers used for connections must be free from any white coating. 3 PREPARATION OF SOLUTION. Weigh 5-50 grams of the finely divided and well mixed sample into a porcelain casserole, the amount selected depending upon the character of the material and the ease with which it is oxidized. With dry, highly nitrogenous substances employ 5 grams; pulped vegetables, 25 grams; liquids with low solid content like beer or 171 172 METHODS OF ANALYSIS [Chap. vinegar, 50 grams. Add 10-15 cc. of the nitric acid, cover the casserole by setting a watch glass inside the rim, convex side upward, heat until vigorous action is over, cool and add 10 cc. of the concentrated sulphuric acid. Heat on a wire gauze over a flame until the mixture turns dark brown or black, then add more nitric acid in 5 cc. portions, heating between each addition until the liquid remains colorless or yellow when evaporated imtil sulphur trioxid fumes are evolved. To remove FIG. 7. APPARATUS FOR THE DETERMINATION OF ARSENIC. completely all nitric or nitrous acid, evaporate to about 5 cc, cool, dilute with 10- 15 cc. of water and again evaporate until white fumes are evolved. Cool, dilute with water, again cool, and make up with water to a definite volume (usually 25-100 cc, depending upon the amount of sample taken and its arsenic content). DETERMINATION. Introduce 20 cc. of the solution or, if the amount of arsenic is large, an aliquot containing not more than 0.03 mg. of AS2O3, prepared as directed in 3, into th« XII] METALS IN FOODS 173 generator of the apparatus described in 2 and add 20 cc. of the dilute sulphuric acid. If the total volume is less than 40 cc, dilute to that volume with water and add 4 cc. of the 20% potassium iodid solution. Heat to about OO^C, add 3 drops of the stannous chlorid solution and heat for 10 minutes. Cool the generator and its contents in a pan containing water and ice; when cold add about 15 grams of the stick zinc and connect the entire apparatus as described in 2. Keep the bottles in ice water for 15 minutes, then remove from the bath and allow the evolution of gas to proceed for an hour longer. Remove the sensitized paper and compare the stain with similar ones produced under like conditions with known amounts of arsenic, using portions of the standard arsenic solution, containing 0.001, 0.002, 0.005, 0.010, 0.015, 0.025 and 0.030 mg. of arsenious oxid (AS2O3), and adding such quantities of water and sulphuric acid that the same volume and acid strength are maintained as above. TIN^ 5 Gravimetric Method. — Tentative. Weigh 50-100 grams of the sample (depending upon the amount of dry substance present and the relative ease with which the organic matter is o.xidized) into an 800 cc. Kjeldahl flask and add 100 cc. of concentrated nitric acid. Allow to stand over- night (this procedure being preferred if much fat or sugar is present) or else place the flask on a wire gauze over a free flame and heat until the contents boil quietly. Add 25-50 cc. of concentrated sulphuric acid (depending upon the amount of dry substance present in the sample), and heat until white fumes are generated, cool somewhat, then add 5-10 cc. of concentrated nitric acid and continue heating as before. Repeat the addition of nitric acid until the solution remains clear after boiling off the nitric acid and fumes of sulphur trioxid appear. Add 200 cc. of water to the digested sample, prepared as directed above, and pour into a 600 cc. beaker. Rinse out the Kjeldahl flask with 3 portions of boiling water so that the total volume of the solution is about 400 cc. Cool, add concentrated ammonia until just alkaline and then hydrochloric or sulphuric acid until the acidity is about 2%. Place the beaker, covered, on a hot plate, heat to about 95°C. and pass in a slow stream of hydrogen sulphid for another hour. Digest on the hot plate for an hour and allow to stand 1-2 hours longer. Filter the tin sulphid on an 11 cm. filter, similar in quality to No. 590, white ribbon, S. & S. Wash alternately with 3 portions each of wash solution (100 cc. of saturated ammonium acetate solution, 50 cc. of glacial acetic acid and 850 cc. of water) and hot water. Digest the filter and precipitate in a 50 cc. beaker with 3 successive portions of ammonium polysulphid, heat to boiling each time and filter through a 9 cm. filter. Wash the precipitate on the filter with hot water. Acidify the filtrate with acetic acid, digest on a hot plate for an hour, allow to stand overnight and filter through a double 11 cm. filter. Wash alternately with 2 portions each of the wash solution and hot water and dry thoroughly in a weighed porcelain crucible. Ignite over a Bunsen flame, very gently at first and later at full heat. The cru- cible, partly covered, is then heated strongly with a large or Meker burner. Stan- nic sulphid must be roasted gently to the oxid, which may be heated strongly with- out loss by volatilization. Weigh as stannic oxid and calculate to metallic tin. Volumetric Method^. — Tentative. 6 RE.\GENTS. (a) Air-free wash solution. — Dissolve 20 grams of sodium bicarbonate in 2 liters of boiled water and add 40 cc. of concentrated hydrochloric acid. This solution should be freshly prepared before use. 174 METHODS OF ANALYSIS [Chap. (b) N / 100 iodin.— The solution must be standardized frequently against (d), con- taining asbestos, and treated as described in 7, omitting the precipitation and boil- ing with hydrochloric acid and potassium chlorate. To obtain exact results the tin solution used for standardization should contain about the same amount of tin as is found in the sample under examination. (C) N/100 sodium thiosulphate. (d) Standard tin solution. — Dissolve 1 gram of tin in about 500 cc. of concen- trated hydrochloric acid. Make up to 1 liter with water. One cc. contains 1 mg. of tin. (e) Sheet aluminium. — Use sheet aluminium, about 30 gauge, free from tin. 7 DETERMINATION. Proceed as directed in 5 to "Digest on the hot plate for an hour and allow to stand 1-2 hours longer". Filter the precipitate of tin sulphid upon asbestos in a Gooch crucible with a detachable bottom, using suction. Wash the precipitate a few times and then transfer the detachable bottom, asbestos pad, and tin precipitate to a 300 cc. Er- lenmeycr flask. Remove all traces of the precipitate from the inside of the cru- cible by means of a jet of hot water and a policeman, using a minimum amount of water for washing. Add 100 cc. of concentrated hydrochloric acid and 0.5 gram of potassium chlorate to the flask. Boil for about 15 minutes, making about 4 more additions of smaller amounts of potassium chlorate as chlorin is boiled out of the solution. Wash the particles of potassium chlorate down from the neck of the flask with water and finally boil to remove chlorin. Then add about 1 gram of the sheet aluminium to dispel the last traces of chlorin. Attach the flasks, in duplicate, as described below, to a large carbon dioxid gener- ator. Pass the carbon dioxid through a scrubber containing water and then divide into 2 streams by means of a Y-tube, each stream of carbon dioxid entering one of the flasks by means of a long rubber tube connected with a bulbed tube, passed through the rubber stopper of the flask and having its lower end near the surface of the liquid in the flask. The carbon dioxid leaves the flask by a second bulbed tube, the opening of which is near the top of the flask. This glass tube is connected by a long rubber tube to a second glass tube about 10 inches long which is immersed in a cylinder containing water. This gives a water-seal to the delivery tube and a pres- sure against which the current of carbon dioxid must work. It also restrains any strong flow of gas when not desired and permits a gas pressure in the Erlenmeyer flask. After the flasks are connected, raise the tubes in the water-seal cylinders so that the generator has practically no pressure to overcome. Allow the carbon dioxid to run for a few minutes. Drop the tubes to the bottom of the cylinders, creating pressure in the flasks. Lift the rubber stoppers of the flasks alternately about a dozen times, in order to force out any air remaining in the flasks. Slightly raise the stopper on one of the flasks and quickly drop about 2 grams of sheet aluminium into the flask. The aluminium should be folded into a strip about 1 cm. wide and slightly bent so as to prevent it from striking directly on the bottom of the flask. After the aluminium has entirely dissolved, raise the tubes in the water-seal cylinders so as to allow carbon dioxid to pass through, place the flasks upon hot plates, and heat to boiling. After boiling for a few minutes, remove the flasks from the hot plates and cool in ice water (or cold running water), still maintaining within them an XII] METALS IN FOODS 175 atmosphere of carbon dioxid. Lower the tubes in the cylinder. When cool, dis- connect the flasks one at a time, putting a glass plug into the carbon dioxid inflow. Wash the tubes, rubber stopper and sides of the flask with the air-free wash solution, add starch paste and titrate at once with the N/100 iodin. If it is desired to titrate by the excess method, run an excess of the N/100 iodin into the flask while it is still connected with the carbon dioxid stream. Then wash out the tubes and titrate the excess of iodin with the N/100 sodium thiosulphate. The rubber connections should be washed with water after each determination. 8 COPPER.— TENTATIVE. Destroy organic matter as directed in 5. Concentrate the sulphuric acid residue by continued digestion to a volume of 10-15 cc, cool, dilute with a little water, trans- fer to a 400 cc. beaker, rinse the Kjeldahl flask with water, adding the rinsings to the contents of the beaker, dilute to about 200 cc. and boil to expel nitrous fumes. Cool, render the solution slightly alkaline with ammonium hydroxid and boil to expel the excess of ammonia. Add 5 cc. of concentrated hydrochloric acid for each 100 cc. of solution, heat to incipient boiling and saturate the solution with hydrogen sul- phid. Allow to stand on a steam bath for a few minutes until the sulphid flocculates, filter and wash the precipitate with hydrogen sulphid water. Protect the precipi- tate from contact with air as much as possible, use only hydrogen sulphid water for washing and carry out this operation without interruption. Reserve the filtrate for the determination of zinc, if necessary. Place the filter containing the copper sulphid precipitate in a small flask, add 4-5 cc. of concentrated sulphuric acid and the same amount of nitric acid and heat until white fumes appear. Continue the oxidation, adding a little nitric acid from time to time, until the liquid remains colorless upon heating to the appearance of white fumes. Cool, dilute with about 30 cc. of water, add an excess of bromin water and boil until all bromin is expelled. Determine the copper as directed in VIII, 29, using N/100 sodium thiosulphate for the titration. 9 ZINC— TENTATIVE. Proceed as directed in 8 to the point indicated by the sentence "Reserve the fil- trate for the determination of zinc, if necessary". Boil the filtrate, containing the zinc, to expel hydrogen sulphid and to reduce the volume to about 250-300 cc, add a drop of methyl orange and 5 grams of ammonium chlorid and make alkaline with ammonium hydroxid. Add dilute hydrochloric acid, drop by drop, until the re- action is faintly acid, then add 10-15 cc. of 50% sodium or ammonium acetate solu- tion and pass in hydrogen sulphid for a few minutes until precipitation is complete. Allow the precipitate to settle, filter, refilter, if necessary, until the filtrate is clear, and wash the precipitate twice with hydrogen sulphid water. Dissolve the precipi- tate on the filter with a little hydrochloric acid (1 to 3), wash the filter with water, boil the filtrate and washings to expel hj'drogen sulphid, cool and add a distinct excess of bromin water. Then add 5 grams of ammonium chlorid and ammonium hydroxid until the color, caused by free bromin, disappears. Add hydrochloric acid (1 to 3), drop by drop, until the bromin color just reappears, then add 10-15 cc. of 50% sodium or ammonium acetate solution and 0.5 cc. of 10% ferric chlorid solu- tion, or enough to precipitate all the phosphates. Boil until all the iron is precipi- tated. Filter while hot and wash the precipitate with water containing a little sodium acetate. Pass hydrogen sulphid into the combined filtrate and washings 176 METHODS OF ANALYSIS until all the zinc sulphid, which should be pure white, is precipitated, filter upon a tared Gooch and wash with hydrogen sulphid water, containing a little ammonium nitrate. Dry the crucible and its contents in an oven, ignite at a bright red heat, cool and weigh as zinc oxid. Calculate the weight of metallic zinc. BIBLIOGRAPHY. 1 U. S. Bur. Chem. Circ. 102; J. Soc. Chem. Ind., 1907, 26: 1115. 2 J. Assoc. Official Agri. Chemists, 1915, 1: 257. ^Proc. Eighth Intern. Cong. Appl. Chem., 1912, 18: 35. Xm. FRUITS AND FRUIT PRODUCTS. 1 PREPARATION OF SAMPLE— TENTATIVE. All samples received in open packages (i.e., not in sterile condition) must be trans- ferred without delay to glass-stoppered containers and kept in a cool place. The determination of alcohol, total and volatile acids, solids and sugars, particularly in the case of fruit juices and fresh fruits, should be made at once as fermentation is liable to begin very soon. Portions for the determinations of sucrose and reducing sugar may be weighed and, after adding a slight excess of neutral lead acetate solu- tion, kept without fermenting for several days if desired. The various products are prepared as directed below. (a) Juices. — Prepare the fresh juice by pressing the well pulped fruit in a jelly bag and filtering through muslin. (b) Jellies and sirups. — Mix thoroughly to insure uniformity in sampling. Weigh 60 grams into a 300 cc. flask, add water, dissolve by frequent shaking, then make up to the mark with water, and use aliquots for the various determinations. If the jelly contains starch or other insoluble material, mix thoroughly before taking the aliquots. (C) Fresh and dried fruits. — Pulp the whole, well cleaned fruit in a large mortar or by means of a food chopper and mix thoroughly. In the case of stone fruits, remove the pits and determine their proportion in a weighed sample. (d) Jams, marmalades, preserves and canned fruits. — Pulp thoroughly the entire contents of the jar or can, as directed under (C); with stone fruits remove the pits and, if desired, determine their proportion in a weighed sample. In the exami- nation of canned fruits it is often sufficient merely to examine the sirups in which the fruits are preserved. In such cases the liquor may be separated and treated as pre- scribed for juices. 2 ALCOHOL.-TENTATIVE. Determine alcohol in 50 grams of the original material as directed under IX, 31 . 3 TOTAL SOLIDS.— TENTATIVE. (a) Juices, jellies and sirups containing no insoluble matter. — Proceed as di- rected in IX, 3, 5, 7 or 10, employing the sample prepared as directed in 1 (a) or (b). (b) Fresh and dried fruits, jams, marmalades, preserves, canned foods and other products containing insoluble matter. — Weigh about 20 grams of pulped fresh fruit, or such an amount of fruit products as will give not more than 3-4 grams of dried material; if necessary to secure a thin layer of the material, add a few cc. of water, mix thoroughly, and dry as directed in DC, 3 or 4. It is to be noted that certain State and Federal regulations require the moisture in dried apples to be determined by drying for 4 hours at the temperature of boiling water. INSOLUBLE SOLIDS. 4 Direct Method.— Tentative. Transfer 50 grams of the sample to a mortar by means of warm water and macerate thoroughly; then transfer to a muslin filter and wash thoroughly with about 500 cc. of warm water, stirring the pulp thoroughly on each addition of water. This amount of water is usually sufficient to remove all soluble material. In extreme cases increase 177 178 METHODS OF ANALYSIS [Chap. the washings to 1000 cc. Transfer the insoluble residue to an evaporating dish, dry and weigh. If it is desired to determine the alcohol precipitate, 18, cool the filtrate, make up to a definite volume and reserve for this determination. 5 Indirect Method. — Tentative. Transfer 25 grams of the fruit product to a 250-500 cc. graduated flask, the size of the flask depending upon the volume of insoluble matter present, add water, shake thoroughly and make up to volume. Allow to settle and either filter or decant the supernatant liquid. Determine the soluble solids in an aliquot, as directed in 3 (a). The fruit must be macerated thoroughly; the use of a mechanical shaker is advisable. The percentage of insoluble solids is the difference between the per- centage of the total solids and the percentage of soluble solids. 6 TOTAL ASH.— OFFICLO-. Determine the ash as directed under VIII, 4, using 50 cc. of the solution of the jelly or diluted sirup, 1 (b), evaporated to dryness, or 25 grams of juice or of fresh or canned fruit, or 10 grams of jam, marmalade, preserves, or dried fruit. 7 ALKALINITY OF THE ASH.— TENTATIVE. Into the platinum dish containing the ash introduce a measured excess of N/5 nitric acid, heat to boiling, cool and add a few drops of methyl orange. Carefully rub up the ash with a rubber-tipped stirring rod and titrate the excess of acid with N/10 potassium or sodium hydroxid. Express the result as the number of cc. of N/10 acid required to neutralize the ash from 100 grams of the sample. 8 SULPHATE AND CHLORID.-TENTATIVE. Wash the solution of the ash, obtained in 7, into a 50 cc. flask and make up to the mark with water. Evaporate 25 cc. of this solution to dryness several times with con- centrated hydrochloric acid, take up the final residue in a small amount of hot water, filter, wash the paper with hot water, acidify the filtrate with a few drops of hydro- chloric acid and determine the sulphate by precipitation with barium chlorid solution. From the weight of barium sulphate calculate the sulphate present as per cent of potassium sulphate. In the other portion of the solution determine the chlorin as directed under III, 15. The nitric acid added before making the titration will, if it contain enough nitrous oxid, completely destroy the red color of the methyl orange and leave a clear solu- tion for the titration. Calculate the chlorin as per cent of sodium chlorid. 9 TOTAL ACIDITY.— TENTATIVE. Dilute 25 cc. of the solution of jelly or diluted sirup, 1 (b), or 10 grams of juice or fresh fruit, with recently boiled water to about 250 cc, or less if the sample be not highly colored; titrate the acid with N/10 alkali, using phenolphthalein as an in- dicator. In the case of highly colored products employ azolitmin solution or phenol- phthalein powder [XVI, 25] on a spot plate instead of phenolphthalein solution. Calculate the results as malic, citric or tartaric acid, specifying the acid used and expressing the results in grams per 100 cc. 10 VOLATILE ACIDS.— TENTATIVE. Dissolve 10 grams of tlie sample, dilute to 25 cc. and distil in a current of steam, as directed under XVI, 27. Each cc. of N/10 alkali is equivalent to 0.0060 gram of acetic acid. XIII] FRUITS AXD FRUIT PRODUCTS 179 11 FREE MINERAL ACIDS.— TENTATIVE. Proceed as directed under XIX, 26, 27 or 28. 12 PROTEIN.— OFFICIAL. Proceed as directed under I, 18, 21 or 23, using 5 grams of jell}' or other fruit product containing a large amount of sugar, or 10 grams of juice or fresh fruit and a larger quantity of the sulphuric acid if necessary for complete digestion. Multi- ply the percentage of nitrogen by 6.25 to obtain the percentage of protein. SUCROSE. 13 By Polarization. — Official. Determine by polarizing before and after inversion, as directed under IX, 22 or 23. 14 By Reducing Sugars Before and After Inversion. — Tentative. Proceed as directed under VIII, 18. 15 REDUCING SUGARS.-TENTATIVE. Proceed as directed under VIII, 25, expressing the results as invert sugar. 16 COMMERCLA.L GLUCOSE.— TENTATIVE. Proceed as directed under IX, 25. 1 7 DEXTRIN.— TENTATIVE. Dissolve 10 grams of the sample in a 100 cc. flask, add 20 mg. of potassium fluorid, and then about one fourth of a cake of compressed yeast. Allow the fermentation to proceed below 2o°C. for 2-3 hours to prevent excessive foaming, and then incu- bate at 27°-30°C. for 5 days. At the end of that time, clarify with basic lead acetate solution and alumina cream, make up to 100 cc. and polarize in a 200 mm. tube. A pure fruit jelly will show a dextro or laevo-rotation of not more than a few tenths of a degree. If a polariscope having the Ventzke scale be used and a 10% solution polarized in a 200 mm. tube, the number of degrees read on the sugar scale of the in- strument multiplied by 0.8755 will give the percentage of dextrin, or the following formula may be used: C X 100 Percentage of dextrin = in which 198 X L X W C = degrees of circular rotation; L = length of tube in decimeters; W = weight of sample in 1 cc. 18 ALCOHOL PRECrPITATE.-TENTATIVE. Evaporate 100 cc. of a 20% solution of jelly or diluted sirup, 1 (b), or of the wash- ings from the determination of insoluble solids, 4, to 20 cc. ; add slowly, with constant stirring, 200 cc. of 95% alcohol by volume and allow the mixture to stand overnight. Filter and wash with 80% alcohol by volume. Wash the precipitate from the filter paper with hot water into a platinum dish; evaporate to dryness; dry at lOCC. for several hours and weigh; then burn off the organic matter and weigh the residue as ash. Designate the loss in weight upon ignition as the alcohol precipitate. The ash should be chiefly lime and not more than 5% of the total weight of the alcohol precipitate. If it is greater than this, some of the salts of the organic acids have been brought down. Titrate the water-soluble portion of this ash with N'lO acid, as any potassium bitartrate precipitated by the alcohol can thus be estimated. 180 METHODS OF ANALYSIS [Chap. STARCH. 19 Qualitative Test. — Tentative. First destroy the color of the jelly by treatment with sulphuric acid and potassium permanganate solution and then test with iodin solution. Bring the solution of jelly nearly to boiling, add several cc. of dilute sulphuric acid and then potassium permanganate solution until all color is destroyed. The starch remains unaffected by this treatment. The presence of starch is not necessarily an indication of its addition as an adulterant. It is usually present in small amount in the apple, and occasionally in other fruits, and unless it is found in the fruit product in consider- able amount its presence may be due to these natural sources. GELATINi. 20 Qualitative Test. — Tentative. The presence of gelatin in jellies and jams is shown by the increased content of nitrogen. Precipitate a concentrated solution of jelly or jam with 10 volumes of absolute alcohol and determine nitrogen in the dried precipitate as directed under I, 18, 21 or 23. AGAR AGAR. QUALITATIVE TESTS. 21 By Microscopic Examination^. — Tentative. Heat the jelly with 5% sulphuric acid, add a crystal of potassium permanganate and allow to settle. If agar agar is present the sediment will be rich in diatoms which can be detected by the use of the microscope. 22 By Precipitation^. — Tentative. Cover 30 grams of the jam or jelly with 270 cc. of hot water, stir until thoroughly disintegrated and boil for 3 minutes. Filter immediately, while still boiling hot, through a filter paper of texture similar to No. 597, S. & S. In the presence of agar agar a precipitate will form upon standing not longer than 24 hours. Filter, wash with cold water and dissolve from the paper by means of a very small amount of boiling water. Upon chilling this hot water solution a firm jelly will be formed that can be examined by the touch. This method will detect 0.2% of agar agar with certainty if the proportions of jam or jelly and water are strictly observed. TARTARIC ACID.-TENTATIVE. 23 PREPARATION OF SOLUTION. Filter fruit juices and employ the filtrate directly. In the case of jellies filter the solution, prepared as directed in 1 (b), and employ the filtrate. In the case of sirups or substances containing insoluble matter like ptilped fruit, jams, marmalades, etc., weigh 50-100 grams, the amount selected being dependent upon the content of solids, of the sample, prepared aS directed in 1 (C) or (d), introduce into a 200 cc. graduated flask, make up to the mark with water, allow to stand for an hour, shake at frequent intervals, filter through a dry paper and use the filtrate. 24 DETERMINATION. Determine the tartaric acid in 100 cc. of fruit juice or the same amount of a solu- tion of the sample, prepared as directed in 23, employing the method given under XVI, 29, except that 20 cc. of alcohol are used in the precipitation instead of 15 cc. XIII] FRUITS AND FRUIT PRODUCTS 181 MALIC ACID. 25 Method I.— Tentative. (For fruit juices and similar products containing no tartaric acid and not over 15% of sugars and in which the color does not interfere with polarization.) Filter the sample, if necessary to secure a solution which can be readily polar- ized, and polarize with white light and a dichromate cell, using a 200 mm. tube if possible. If the sample contains free mineral acid, transfer a measured portion (75 cc. is a convenient volume) to a 100 cc. graduated flask, add enough standard alkali, cal- culated from the acidity as determined in 9, to neutralize the total acidity, dilute to the mark, mix well and filter. If no free mineral acids are present, it is unneces- sary to neutralize the sample. If neutralized, proper correction must be made for dilution in making the final calculation. Transfer 25 cc. of the sample, or a neutralized solution, to a flask graduated at 25 and 27.5 cc, add about 2.5 grams of powdered uranyl acetate, and shake vigorously at frequent intervals for 3 hours, keeping the mixture well protected from light. If all of the uranyl acetate dissolves, add more so that a small amount remains undissolved at the end of 3 hours. Dilute the solution to the 27.5 cc. mark with saturated uranyl acetate solution, mix well and filter, if necessary, through a folded filter. Polarize, if possible, in a 200 mm. tube. If the solution is too dark to polarize in a 200 mm. tube, a 100 or 50 mm. tube may be used. Multiply the reading by 1.1 to correct for the dilution. Multiply the algebraic difference in degrees Ventzke between the 2 readings cal- culated to the basis of a 200 mm. tube by the factor 0.036 to obtain the weight of malic acid in the sample in grams per 100 cc. Make all polarizations at the same room temperature with white light and with a dichromate cell. Make at least 6 readings in each case and take an average of these. In the case of dark colored fruit juices which cannot be polarized readily, approxi- mately quantitative results may be obtained by adding to the solutions a few drops of bromin, shaking thoroughly and filtering just before polarization. Method II. — Tentative. (Approximate determination for fruit juices and similar products con- taining no tartaric acid and more than 15% of sugars.) 26 PREPARATION OF SOLUTION^ Weigh out 25 grams of the sample and transfer to a 600 cc. beaker with a little 95% alcohol by volume. Add alcohol a little at a time until 200 cc. have been added, stirring the mixture well, and warming, if necessary, to insure solution of all alcohol- soluble substances. Filter on a BUehner funnel, using suction, and thoroughly wash the precipitated pectins and insoluble matter with 95% alcohol, disregarding any slight turbidity which may appear in the filtrate after the washings have been added. From 9, calculate the amount of N/4 barium hydroxid required nearly to neutralize the acidity in the 25 grams of sample taken. To the com- bined filtrate and washings in an Erlenmeyer flask add the calculated quantity of barium hydroxid solution, stir until reaction is complete and then add 3-5 drops, or more if required, of 50% barium acetate solution to insure an excess of barium. Make up the volume of the mixture to about 375 cc. (not less) with alcohol, and re- flux until the precipitate settles readily after being shaken. This may require 3—1 182 METHODS OF ANALYSIS [Chap. hours. Filter with suction and thoroughly wash the precipitate in the flask and on the paper with 95% alcohol by volume. Transfer the portion on the filter to the original flask, rinsing the paper with a jet of hot water. Digest the pre- cipitate with hot water, containing 2 grams of sodium sulphate in solution, un- til the reaction is complete, and boil until the barium sulphate precipitate settles readily. Concentrate by evaporation, if necessary, and transfer to a 100 cc. vol- umetric flask with a little hot water, cool, make up to volume with water and filter. 27 DETERMINATION. Transfer 25 cc. of the filtrate, obtained in 26, to a flask graduated at 25 and 27.5 cc, add about 2.5 grams of pulverized uranyl acetate and shake vigorously at frequent intervals for 3 hours, keeping the solution well protected from light. If all the uranyl acetate dissolves, add more so that a small amount remains undissolved at the end of 3 hours. Dilute the solution to the 27.5 cc. mark with saturated uranyl acetate solution, mix well, filter if necessary, and polarize in a 200 mm. tube, using the same precautions as described in 25. Multiply the reading, calculated to the basis of a 200 mm. tube, by 1.1 to correct for the dilution. Polarize another portion of the filtrate, obtained in 26, which has not been treated with uranyl acetate. Multiply the algebraic difference in degrees Ventzke between the 2 readings, calculated to the basis of a 200 mm. tube, by the factor 0.036 to obtain the weight of malic acid in grams per 100 cc. in the solution as obtained in 26. Method III. — Tentative. (Approximate determination for products containing tartaric acid.) 28 PREPARATION OF SOLUTION^. Prepare the sample as directed under 26 up to the point of filtration and washing of the barium malate precipitate, then dry the precipitate thoroughly and transfer the portion on the filter to the original flask, rinsing the paper with a jet of hot water. Digest the precipitate with hot water, transfer to a 100 cc. volumetric flask with a little hot water, cool, make up to volume with water and filter to re- move insoluble barium tartrate. This amount of water is sufficient to dissolve barium malate up to amounts as large as approximately 0.9 gram in 100 cc. More than 100 cc. of water must be used when more than 0.9 gram of barium malate is present. The amount of barium tartrate dissolved by hot water is so small as to affect only slightly the polarization after treatment with uranyl acetate. 29 DETERMINATION. Proceed as directed in 27, using the solution prepared as directed in 28. CITRIC ACID^— TENTATIVE. CApplicable in the presence of sugar and malic and tartaric acids.) 30 REAGENTS. (a) Barium hydroxid solulion. — Approximately N/4. (b) 50% barium acetate solution. (C) Sulphuric acid (1 to 1) and (/ to 5). (d) Potassium or sodium broynid solution. — Dissolve 15 grams of potassium bromid in 40 cc. of water or 16 grams of sodium bromid in 50 cc. of water. XIII] FRUITS AND FRUIT PRODUCTS 183 (e) 6% potassium permanganate solution. (f) Ferrous sulphate solution. — Dissolve 20 grams of ferrous sulphate in 100 cc. of water containing 1 cc. of concentrated sulphuric acid. (g) Bromin water. — Freshly prepared, saturated solution. 31 DETERMINATION. Proceed as directed in 26 up to "Filter with suction and thoroughly wash the precipitate in the flask and on the paper with 95% alcohol by volume". Transfer the precipitate from the filter to the flask with a jet of hot water, boil until alcohol can no longer be detected by odor, and add enough of the sulphuric acid (1 to 5) to precipitate all the barium originally added and to allow 2 cc. in excess. Evaporate by careful boiling to a volume of 60-70 cc, cool and add 5 cc. of freshly prepared saturated bromin water, or enough to show a distinct excess. Transfer with water to a 100 cc. volumetric flask and dilute to the mark at standard temperature. Mix thoroughly, allow the precipitate to settle and filter through a dry paper. The precipitate may be separated by centrifugalizing and the super- natant liquid decanted, if necessary. Pipette an aliquot of the filtrate, containing not more than 250 mg. of citric acid, calculated from the total acidity of the sample, into a 300 cc. Erlenmeyer flask. If possible, the amount of citric acid in the ali- quot should exceed 50 mg. Add 10 cc. of the sulphuric acid (1 to 1) and 5 cc. of the potassium or sodium bromid solution, mix, warm the flask in a water bath to4S°-50°C. and allow it to remain in the bath for 5 minutes. After removing from the bath add rapidly from a pipette, drop by drop with frequent interruptions, 25 cc. of the 5% potassium permanganate solution and shake vigorously; avoiding a temperature during oxidation exceeding 55°C. Set the flask aside until the hydrated peroxid of manganese begins to settle. The supernatant liquid should be dark brown, showing an excess of permanganate; if an excess is not indicated, add more permanganate. Shake, again set aside to settle and repeat this operation until the precipitate assumes a yellow color and most of it has dissolved. Finally, while the solution is still warm, remove the last undissolved portion of hydrated peroxid of manganese precipitate and also the excess of bromin by adding, drop by drop, the clear ferrous sulphate solution. Allow the solution to cool, shaking occasionally. If the opera- tions have been properly conducted, a heavy white precipitate of pentabromacetone is obtained which becomes crystalline on occasional shaking and in this condition is entirely insoluble in water. Allow the mixture to stand overnight, collect it by means of gentle suction on a tared Gooch crucible provided with a thin pad of asbestos, previously dried over sulphuric acid in a vacuum desiccator, wash with water slightly acidified with sulphuric acid and finally wash twice with water. Dry the precipitate to constant weight over sulphuric acid in a vacuum desiccator, protecting the precipi- tate from strong light. The weight of pentabromacetone multiplied by the factor 0.424 gives the equivalent weight of anhydrous citric acid (HsCeHjO?). Occasionally the pentabromacetone is first obtained in the form of oily droplets. These become crystalline on standing or on cooling and are usually discolored by negligible traces of manganese or iron. The above method may bo applied directly to the sample without previous pre- cipitation of the citric acid as the barium salt when the amount of sugar or other permanganate reducing substances is not excessive. In this case begin the deter- mination with the addition of 2 cc. of sulphuric acid (1 to 5) and the treatment with bromin water. 32 METALS.-TENTATIVE. Proceed as directed under XII. 184 METHODS OF ANALYSIS 33 PRESERVATIVES.-TENTATIVE. Proceed as directed under X. 34 COLORING MATTERS.-TENTATIVE. Proceed as directed under XI. 35 SWEETENING SUBSTITUTES.-TENTATIVE. Proceed as directed under X, 12, 36 or 37. BIBLIOGRAPHY. 1 Chem. Ztg., 1895, 19: 552. " Z. angew. Mikros., 1896, 2: 260. " Z. Nahr. Genussm., 1911, 21: 185. * J. Assoc. Official Agri. Chemists, 1915, 1: 480. 6 Ibid.; U. S. Bur. Chem. Bull. 162, p. 65. 6 Arch. Chem. Mikros., 1914, 7: 285; Abs. Z. Nahr. Genussm., 1915, XIV. CANNED VEGETABLES. 1 PHYSICAL EXAMINATIONS-TENTATIVE. Note carefully the external appearance of the packages to detect the presence of "leakers", "swells" or "springers". In general the ends of sound tins of canned vegetables are slightly concave. On opening the package note the relative pro- portion of solid and liquid contents and the level of the solids and of the total con- tents in the tin. Note the general appearance, odor, flavor, color and size of the vegetables; appearance of the liquor or brine, whether clear or turbid, and the con- dition of the inner walls of the container, especially as to blackening and corrosion. In all instances the analyst should familiarize himself with the normal appearance, odor, color, flavor and other properties of the product under examination. Care- ful macroscopic or microscopic examination should be made for worm infestation, mold, dirt, or other evidence of decomposition or filth. 2 PREPARATION OF SAMPLE.— TENTATIVE. The preparation of the sample for analysis depends upon the character of the product and the determinations to be made. Samples in which only the solid or liquid portion is required should be treated as follows: Weigh the full can, open, pour off the liquid, allow the solid portion to drain for a minute, re-weigh the can and drained vegetables, then remove the solid portion and weigh the dry, empty can. The method selected for draining the vegetables is dependent upon the nature and condition of the sample. In most cases it is sufficient to cut around the cover and before turning it back allow the liquor to drain through the slit. Whenever a portion of the solid material would escape with the liquor by this procedure, drain upon a piece of cheese-cloth. From the weights thus obtained determine the per- centage of liquid and solid contents. If only the solid portion is required, separate in a similar manner and grind thoroughly the drained vegetables in a mortar or food chopper. If a composite of the solid and liquid portion is required, grind thoroughly the contents of the can in a mortar or food chopper. In all cases mix thoroughly the portion used and preserve the balance in glass-stoppered containers. Unless the analysis is to be completed in a reasonably short time, determine the moisture in a portion of the sample prepared as above and, in order to prevent decom- position, dry the remainder and then expose to air until it becomes air-dry, grind, mix thoroughly and preserve in glass-stoppered containers. A second moisture determi- nation is required in this procedure. 3 MOISTURE.-TENTATTVE. Dry a quantity of the sample, representing about 2 grams of dry material, as directed in EX, 2. 4 ASH.-OFFICIAL, Determine total ash as directed in VIII, 4. 5 SALT.-OFFICIAL. Determine chlorin as directed under HI, 1 5, and express the result in terms of sodium chlorid. 185 18G METHODS OF ANALYSIS 6 SUGARS.— TENTATIVE. Determine reducing sugars and sucrose as directed in VIII, 58 and 59, varying the weight of the sample employed according to its sugar content. 7 TOTAL ACIDS.-TENTATIVE. Proceed as directed in XVI, 25. Express the result as citric acid; 1 cc. of N/10 alkali is equivalent to 0.0070 gram of crystallized citric acid. 8 VOLATILE ACIDS.-TENTATIVE. Proceed as directed in XVI, 27. Express the results as acetic acid; 1 cc. of N/10 alkali is equivalent to 0.0060 gram of acetic acid. 9 PRESERVATIVES.-TENTATIVE. Proceed as directed under X. 10 COLORING MATTERS.-TENTATFVE. Proceed as directed under XI. 1 1 METALS.— TENTATIVE. Proceed as directed under XII. BIBLIOGRAPHY. 1 U. S. Bur. Chem. Bulls. 125 and 151 ; U. S. Dept. Agr. Bull. 196; U. S. Bur. Chem. Circ. 54; Research Laboratory, National Canners Association, Bull. 2. XV. CEREAL FOODS. WHEAT FLOUR. 1 MOISTURE.-OFFICIAL. Determine moisture as directed in VIII, 2. 2 ASH.-OFFICIAL. Determine ash as directed in VIII, 4, using 5 grams of the flour. 3 CRUDE FAT OR ETHER EXTRACT.-OFFICIAL. Determine the ether extract as directed in VIII, 10. With fine flour the addition of an equal weight of clean, dry sand is frequently necessary. 4 CRUDE FIBER.-OFFICIAL. Determine crude fiber as directed in VIII, 68. 5 ACIDITY OF WATER EXTRACT.— TENTATIVE. Weigh 18 grams of the flour into a 500 cc. Erlenmeyer flask and add 200 cc. of carbon dioxid-free water. Place the flask, loosely stoppered, for an hour in a water bath kept at 40°C., shaking occasionally. Filter upon a dry, folded filter, return- ing the first 10-15 cc. of the filtrate to the filter. Titrate 100 cc. of the clear filtrate with N/20 sodium hydroxid, using phenolphthalein as an indicator. Each cc. of N/20 sodium hydroxid is equivalent to 0.05% acidity as lactic acid. 6 SUGARS.-TENTATIVE. Determine reducing sugars and sucrose as directed in VIH, 58 and 59. 7 PROTEIN.-OFFICIAL. Determine nitrogen as directed in I, 18, 21 or 23. Multiply the percentage of nitrogen by 5.7 to obtain the percentage of protein. ALCOHOL-SOLUBLE PROTEIN. 8 Method I. {By nitrogen determination) — Tentative. Transfer 4 grams of the flour to a 15O-200 cc. bottle or Erlenmeyer flask and add 100 cc. of 70% alcohol by volume, taking care that none of the material sticks to the bottom of the container. Shake thoroughly 10-12 times at intervals of 30 minutes at room temperature, or shake continuously in a shaking machine for an hour, and then set aside overnight. Shake thoroughly once more, allow to settle and filter through a drj^ folded filter, returning the first runnings to the filter until a clear filtrate is obtained. 'Pipette 50 cc. of the filtrate, equivalent to 2 grams of the sample, into a Kjeldahl flask, dilute with 100 cc. of water to prevent frothing during digestion and determine nitrogen as directed in I, 18, 21 or 23. 1S7 188 METHODS OF ANALYSIS [Chap. 9 Method II. {By Polarization) — Tentative. REAGENT. Millon's reagent. — Dissolve metallic mercury in an equal weight of concentrated nitric acid and dilute the solution with an equal volume of water. The freshly prepared solution must be used. 1 0 DETERMINATION. Weigh 15.97 grams of the flour into a 300 cc. flask and add 100 cc. of alcohol (sp. gr. 0.90). Shake at 30 minute intervals for 3 hours and then let stand overnight. Filter through a dry, folded filter and polarize in a 200 mm. tube. Precipitate the proteins in 50 cc. of the filtrate by the addition of 5 cc. of Millon's reagent. Shake, filter and polarize the filtrate in a 200 mm. tube. Multiply the reading in degrees Ventzke by 1.1 to correct for the dilution and deduct the product from the first reading. This difference multiplied by 0.2 gives the per cent of gliadin^ nitrogen. 1 1 PROTEIN SOLUBLE IN 5 PER CENT POTASSIUM SULPHATE SOLUTION.— TENTATIVE. Weigh 6 grams of the flour into a 200 cc. flask and introduce exactly 100 cc. of 5% potassium sulphate solution. Shake at 30 minute intervals for 3 hours and let stand overnight or, better still, agitate at moderate speed in a shaker for 3 hours, let settle 30 minutes, filter and determine the nitrogen in 50 cc. of the filtrate as directed in I, 18, 21 or 23. 12 GLOBULIN AND ALBUMIN (EDESTIN AND LEUCOSIN) AND AMINO NITROGENS- TENTATIVE. Weigh 10 grams of the flour into a 500 cc. Erlenmeyer flask, add 250 cc. of 1% sodium chlorid solution, stopper the flask and shake thoroughly. Let stand, with occasional shaking, for 3 hours, filter through dry paper and evaporate 100 cc. of the filtrate to a small volume in a Kjeldahl digestion flask with 5 cc. of concentrated sulphuric acid. Add the remainder of the sulphuric acid and determine the nitro- gen as directed in I, 18, 21 or 23. To a second 100 cc. of the filtrate add 5 cc. of 20% phosphotungstic acid solution, shake thoroughly, allow to settle and filter by de- cantation. Wash slightly with water, concentrate the filtrate with 5 cc. of sul- phuric acid in a Kjeldahl flask and determine the nitrogen (amino) as directed in I, 18, 21 or 23. Deduct the amino nitrogen from the nitrogen found in the first frac- tion to obtain the nitrogen as globulin and albumin'. ■13 GLUTENIN.— TENTATIVE. Deduct the sum of the potassium sulphate-soluble nitrogen, 1 1 , and the alcohol- soluble nitrogen, 8, from the total nitrogen, 7, and multiply the difference by 5.7. 14 COLD WATER-SOLUBLE EXTRACT.— TENTATIVE. Weigh 20 grams of the flour into a 500 cc. Erlenmeyer flask and add gradually 200 cc. of water at 10°C., shake vigorously when about 50 cc. of water have been added and continue shaking during the addition of the remainder. Allow to stand at 10°C. for 40 minutes, shaking occasionally. Filter through a large, dry, coarse filter paper, returning the first runnings to the filter until a clear filtrate is obtained. Pipette 20 cc. of the clear filtrate into a tared dish, evaporate to dryness on a steam bath, and dry to constant weight in an oven at 100°C. for periods of 30 minutes. XV] CEREAL FOODS 189 GLUTEN. 15 Bamihl Test. (Qualitative) — Tentative. Place a very small quantity (about 1.5 mg.) of the flour on a microscope slide, add a drop of water, containing 0.2 gram of water-soluble eosin in 1 liter, and mix by means of a cover-glass, holding the latter at first in such a manner that it is raised slightly above the slide, and taking care that none of the flour escapes from beneath it. Finally allow the cover-glass to rest on the slide and rub it back and forth until the gluten has collected into rolls. The operation should be carried out on a white paper so that the formation of gluten rolls can be noted. Wheat flour, or other flours containing gluten, show by this treatment a copious amount of gluten, which absorbs the eosin with avidity, assuming a carmine color. Rye and corn flour yield only a trace of gluten, and buckwheat flour no appreciable amount. The preparations are best examined with the naked eye, thus gaining an idea of the amount of gluten present. If the flour is coarse, or contains a considerable amount of bran elements, as is true of buckwheat flour and low-grade wheat flour, the test should be made after bolting, as the bran particles and coarse lumps interfere with the formation of gluten rolls. 16 Quantitative Method. — Tentative. Weigh 25 grams of the flour into a cup or porcelain mortar, add sufficient tap water (about 15 cc.) to form a firm dough ball and work into a dough with a spatula or pestle, taking care that none of the material adheres to the utensil employed. Allow the dough to stand in water at room temperature for an hour, then knead gently in a stream of tap water until the starch and all soluble matters are removed. This operation requires approximately 12 minutes and should be performed over bolting cloth or a horsehair sieve. To determine if the gluten is starch-free let 1 or 2 drops of the wash water, obtained by squeezing the gluten, fall into a beaker containing perfectly clear water. If starch is present a cloudiness appears. Allow the gluten thus obtained to stand in water for an hour, then press as dry as possible between the hands, roll into a ball, place in a tared, flat-bottomed dish and weigh as moist gluten. Transfer to an oven, dry to constant weight at 100°C. (about 24 hours), cool and weigh as dry gluten. CHLORIN. 17 Qualitative Test. (Chlorin-Bleached Flours) — Tentative. Extract 30 grams of the flour with gasoline and allow the latter to evaporate. A small amount of oil remains. Heat a piece of copper wire in a colorless gas flame until it is black and no longer colors the flame green. Dip the hot end of the wire into the oil and again bring into the flame. If chlorin or bromin has been used as a bleaching agent, a green or blue coloration is produced. 18 Quantitative Method. {Added Chloriri in Chlorin-Bleached Flours) — Tentative. Weigh 20 grams of the flour into a flat-bottomed aluminium dish, 8-10 cm. in diameter, and dry 5 hours in a boiling water or steam oven, transfer, with as little exposure to the air as possible, to a continuous fat extractor, and extract for 16 hours with anhydrous alcohol-free ether, which is also free from chlorin. Transfer the ether extract to a nickel disl^ and add 25 cc. of a solution containing 25 grams of sodium hydroxid and 15 grams of sodium nitrate per liter. Place the dish on a steam bath, evaporate to dryness and ignite in a muflSe at a dull red heat until 190 METHODS OF ANALYSIS [Chap. the contents are thoroughly charred. Extract the charred mass with 25 cc. of 1% nitric acid and filter. Return the residue to the dish, char and again extract with 25 cc. of 1% nitric acid, filter, wash with hot water, return to the dish and ignite to a white ash. Dissolve the ash in 5% nitric acid and add the solution to the filtrates previously obtained. Determine the chlorin in the combined filtrates either gravi- metrically, as directed in I, 16 (a), or volumetrically, as directed in III, 15, using N/50 solutions for greater accuracy. NITRITE NITROGEN.— TENTATIVE. 19 REAGENTS. (a) Sulphanilic acid solution. — Dissolve 0.5 gram of sulphanilic acid in 150 cc. of 20% acetic acid. (b) Alpha-naphthylamin hydrochlorid solution. — Dissolve, by heating, 0.2 gram of the salt in 150 cc. of 20% acetic acid. (C) Standard nitrite solution. — Dissolve 0.1097 gram of dry C. P. silver nitrite in about 20 cc. of hot water, add 0.10 gram of C. P. sodivun chlorid, shake until the silver chlorid flocculates and make up to 1 liter. Draw off 10 cc. of the clear solution and dilute to 1 liter. Each cc. of the last solution is equivalent to 0.0001 mg. of nitrogen as nitrite. [Cf. IV, 12 (d)] The silver nitrite may be prepared as follows : To a cold solution of about 2 grams of sodium or potassium nitrite in 50 cc. of water, add a solution of silver nitrate as long as a precipitate appears. Decant the liquid and thoroughly wash the precipitate with cold water. Dissolve in boiling water. On cooling the silver nitrite crystallizes out. Dry the crystals in the dark at ordinary temperature (pre- ferably in a vacuima). 20 DETERMINATION. (1) Select a series of 100 cc. volumetric flasks of uniform dimensions and color. Place 2 grams of high-grade, nitrite-free flour in each; add approximately 70 cc. of nitrite-free water and shake until the flour is thoroughly moistened. Add to these flasks varying amounts of the standard sodium nitrite solution, so that a series of comparison standards will be obtained having a range covering the probable nitrite content of the unknown sample. Reserve 1 flask for a blank test. In order to avoid making a large series of standards it is well to make a preliminary test to as- certain the approximate nitrite content of the unknown. Where the quantity of nitrite present is small, the nitrite solution in the flasks may be increased by 0.4 cc. each. Where bleaching is excessive, 1 gram of flour may be used throughout, or the standards may be given a wider variation in nitrite content. To each of 2 similar flasks add 2 grams of the flour and 90 cc. of water; shake thoroughly and digest all the flasks, including the blank, in a water bath at 40°C. for at least 15 minutes; add 2 cc. each of the sulphanilic acid and alpha- naphthylamin hydrochlorid solutions to each flask. Continue the digestion at 40°C. for an additional 20 minutes. The color must be developed in all the flasks under conditions as nearly uniform as possible. Make up to the marks with nitrite- free water and compare the unknown with the series of standards. This may be done in a large, white, enameled pan; the effect of the turbidity, due to the flour, being minimized by the white background. The solutions should be allowed to subside and should not be shaken during comparison; or, (2) Weigh 20 grams of the flour into a 500 cc. Erlenmeyer flask, add 200 cc. of nitrite-free water, previously warmed to 40°C., and close the flask with a rubber stopper. Shake vigorouslj^ for 5 minutes and digest for an hour in a water bath, XV] CEREAL FOODS 191 keeping the temperature of the liquid in the flask at 40°C. and shaking at 10 minute intervals. Finally filter on a dry, nitrite-free, folded filter. Return the first run- nings to the filter until a clear filtrate is obtained. Pipette 50 cc. of the filtrate and 50 cc. of the standard nitrite solution into small flasks; add to each, 50 cc. of water, 2 cc. each of the sulphanilic acid and alpha-naphthylamin hydrochlorid solutions, shake and allow to stand an hour to bring out the color. Compare the 2 solutions in a colorimeter. Divide the height of the column of the standard solution by that of the solution of the sample to obtain the parts of nitrogen as nitrous acid (free and combined) per million of flour. 21 GASOLINE COLOR VALUE.-TENTATIVE. Place 20 grams of the flour in a wide-mouthed, glass-stoppered 120 cc. bottle and add 100 cc. of colorless gasoline. Stopper tightly and shake vigorously for 5 minutes. After standing 16 hours, shake again for a few seconds until the flour has been loos- ened from the bottom of the bottle and thoroughly mixed with the gasoline, then filter immediately on a dry 11 cm. paper into an Erlenmeyer flask, keeping the fun- nel covered with a watch glass to prevent evaporation. In order to secure a clear filtrate, a certain quantit}^ of the flour should be allowed to pass over onto the paper and the first portion of the filtrate passed through a second time. It will be found convenient to fit the filter paper to the funnel by means of water and dry thoroughly either by standing overnight in a well-ventilated place or by heating. Determine the color value of the clear gasoline solution in a Schreiner or similar colorimeter, using for comparison a 0.005% potassium chromate solution. This solu- tion corresponds to a gasoline number of 1.0 and is conveniently prepared by dilu- ting 10 cc. of a 0.5% solution to 1 liter. The colorimeter tube, containing the gasoline solution, should first be adjusted so as to read 50 mm., then the tube containing the standard chromate solution raised or lowered until the shades of yellow in both tubes match. The reading of the chromate solution, divided by the reading of the gasoline solution, gives the gasoline color value. The color value may be deter- mined also in Nessler tubes, using for comparison potassium chromate solutions of various dilutions prepared from a 0.5% solution and filling the tubes in all cases to the height of 50 mm. BIBLIOGRAPHY. » U. S. Bur. Chem. Bull. 152, p. 104. * Ibid., 81, p. 124. » Ibid., 122, p. 54. XVI. WINES. 1 PHYSICAL EXAMINATION.-TENTATIVE. Note the following: whether the container is "bottle full"; the appearance of the wine, whether there is any sediment and if it is bright or turbid; condition when opened, whether still, gaseous or carbonated; color and depth of color; odor, whether vinous, acetous, pleasant or foreign; and taste, whether vinous, acetous, sweet, dry or foreign. 2 PREPARATION OF SAMPLE.— TENTATIVE. If gas is contained in the wine, remove it by pouring back and forth in beakers. Filter the wine, regardless of appearance, before analysis and determine immedi- ately the specific gravity and such ingredients as alcohol, acids and sugars as are liable to change through exposure. 3 SPECIFIC GRAVITY.-TENTATIVE. Determine the specific gravity at -^s—^ by means of a pycnometer. 4 ALCOHOL.— TENTATIVE. (a) By volume.— Measure 100 cc. of the liquid at 20°C. into a 300-500 cc. distilla- tion flask, add 50 cc. of water, attach the flask to a vertical condenser by means of a bent tube and distil almost 100 cc, making up to 100 cc. volume when cooled to 20°C. Foaming, which sometimes occurs, especially with young wines, may be prevented by the addition of a small amount of tannin. To determine the alcohol in wines which have undergone acetous fermentation and contain an abnormal amount of acetic acid, exactly neutralize the portion taken with sodium hydro.xid solution before distilling. This is unnecessary, however, in wines of normal taste and odor. Determine the specific gravity of the distillate at -p— ^ and obtain the correspond- ing percentage of alcohol by volume from 5. (b) Grams per 100 cc— From the specific gravity of the distillate, obtained in (a), ascertain from 5 the corresponding alcohol content in grams per 100 cc. (C) By weight. — Divide the number of grams in the 100 cc. of distillate, as ob- tained in (b), by the weight of the sample as calculated from its specific gravity. (d) By immersion refradometer.— The percentages of alcohol, as determined in (a) and (C), may be verified by determining the immersion refractometer reading of the distillate and obtaining, from 6, the corresponding percentages of alcohol. 193 194 METHODS OF ANALYSIS [Chap. Table 16.— Alcohol Table. (Calculated by the U. S. Bureau of Standards from its experimental results^) For calculating the percentages of alcohol in mixtures of ethyl alcohol and water from their specific gravities. SPECIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL GRAVITY 20° 0. Per cent Per Grams ORAVITT 20° C. Per cent Per Grams 20° C. Per cent Per Grams 4° by volume cent by per 4° by volume cent by per 4° by volume cent by per at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° 0. weight 100 cc. 0.99823 0.00 0.00 0.00 0.99492 2 25 1.79 1.78 0.99174 4.50 3.58 3.55 0.99815 0.05 0 OJf. 0.04 0.99485 2 30 1.82 1.81 0.99168 4.55 3.62 3.59 0.99808 0.10 0.08 0.08 0.99477 2.35 1.86 1.85 0.99161 4.60 3.66 3.63 0.99800 0.15 0.12 0.12 0.99470 2.40 1.90 1.89 0.99154 4.65 3.70 3.67 0.99793 0 20 0.16 0.16 0.99463 2.45 1.94 1.93 0.99147 4.70 3.74 3.71 0.99785 0 25 0.20 0.20 0.99456 2 50 1.98 1.97 0.99140 4.75 3.78 3.75 0.99778 0 30 0.21, 0.24 0.99449 2.55 2.02 2.01 0.99133 4 80 3.82 3.79 0.99770 0 35 0.28 0.28 0.99442 2.60 2.06 2.05 0.99127 4.85 3.86 3.83 0.99763 0 40 0.32 0.32 0.994.34 2 65 2.10 2.09 0.99120 4.90 3.90 3.87 0.99755 0.45 0.36 0.36 0.99427 2.70 2.14 2.13 0.99113 4.95 3.94 3.91 0.99748 0.50 0.40 0.40 0.99420 2.75 2.18 2.17 0.99106 5.00 3.98 3.95 0.99741 0 55 O.U 0.44 0.99413 2.80 2.22 2.21 0.99100 5.05 4.02 3,99 0.99734 0.60 0.47 0.47 0.99405 2.85 2.26 2.25 0.99093 5 10 4.06 4.03 0.99726 0 65 0.51 0.51 0.99398 2 90 2.30 2.29 0.99087 5.15 4.10 4.07 0.99719 0.70 0.55 0.55 0.99391 2 95 2.34 2.33 0.99080 5.20 4.14 4.10 0.99711 0.75 0.59 0.59 0.99384 3 00 2.38 2.37 0.99073 5.25 4.18 4.14 0.99704 0.80 0.6S 0.63 0.99.377 3 05 2.42 2.41 0.99066 5 30 4.22 4.18 0.99697 0.85 0.67 0.67 0.99.370 3 10 2.46 2.45 0.99060 5.35 4.26 4.22 0.99690 0 90 0.71 0.71 0.99.362 3 15 2.50 2.49 0.99053 5.40 4.30 4.26 0.99682 0.95 0.75 0.75 0.99355 3.20 2.54 2.53 0.99047 5.45 4.S4 4.30 0.99675 1.00 0.79 0.79 0.99.348 3 25 2.58 2.57 0.99040 5.50 4.38 4.34 0.99667 1 05 0.83 0.83 0.99341 3 30 2.62 2.60 0.99033 5.56 4-42 4.38 0.99660 1.10 0.87 0.87 0.99334 3 35 2.66 2.64 0.99026 5 60 4-46 4.42 0.99652 1.15 0.91 0.91 0.99327 3 40 2.70 2.68 0.99020 5.65 4.50 4.46 0.99645 1.20 0.95 0.95 0.99320 3 45 2.74 2.72 0.99013 5.70 4-54 4.50 0.99638 1 25 0.99 0.99 0.99313 3 50 2.78 2.76 0.99006 5.75 4.58 4.54 0.99631 1 30 1.03 1.03 0.99306 3 55 2.82 2.80 0.98999 5.80 4.62 4.58 0.99623 1 35 1.07 1.07 0.99299 3 60 2.86 2.84 0.98993 5 85 4.66 4.62 0.99616 1 40 1.11 1.11 0.99292 3 65 2.90 2.88 0.98986 5.90 4.70 4.66 0.99608 1.45 1.15 1.15 0.99285 3.70 2.94 2.92 0.98980 5.95 4.74 4.70 0.99601 1.50 1.19 1.19 0.99278 3 75 2.98 2.96 0.98973 6 00 4.78 4.74 0.99.594 1.55 1.23 1.23 0.99271 3 80 3.02 3.00 0.98967 6 05 4.82 4.78 0.99587 1.60 1.27 1.26 0.99264 3.85 3.06 3.04 0.98960 6.10 4.87 4.82 0.99579 1 65 1.31 1.30 0.99257 3 90 3.10 3.08 0.98954 6.15 4.91 4.86 0.99572 1.70 1.35 1.34 0.99250 3 95 3.14 3.12 0.98947 6.20 4.95 4.89 0.99564 1 75 1.39 1.38 0.99243 4.00 3.18 3.16 0.98941 6.25 4.99 4.93 0.99557 1.80 1.43 1.42 0.992.36 4.05 3.22 3.20 0.98934 6 30 5.03 4.97 0.99550 1.85 1-47 1.46 0.99229 4.10 3.26 3.24 0.98928 6 35 5.07 5.01 0.99543 1 90 l.r>l 1.50 0.99222 4.15 3.30 3.28 0.98921 6.40 5.11 5.05 0.99535 1.95 1.55 1.54 0.99215 4.20 3.34 3.32 0.98915 6.45 5.15 5.09 0.99528 2.00 1.59 1.58 0.99208 4.25 3.3S 3.36 0.98908 6 50 5.19 5.13 0.99520 2 05 1.63 1.62 0.99201 4 30 3.42 3.39 0.98902 6.55 5.23 5.17 0.99513 2.10 1.67 1.66 0.99195 4.35 3.46 3.43 0.98895 6 60 5.27 5.21 0.99.506 2.15 1.71 1.70 0.99188 4.40 3.50 3.47 0.98889 6 65 5.31 5.25 0.99499 2.20 1.75 1.74 0.99181 4.45 3.54 3.51 0.98882 6.70 5.35 5.29 XVI] WINES 195 ! Table 16.— Alcohol Table- -Continued. PECIFIC ALCOHOL SPECIFIC ALCOH'JL SPECIFIC ALCOHOL RAVITY 20° C. Per cent Per Grama °Iqo^^ Per cent Per Grams GR.WITY 20° C. Per cent Per Grams 4° by volume cent by per 4° by volume cent by per 4° by volume cent by per at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 cc. 1.98876 6 75 5.S9 5.33 0.98566 9 25 7.41 7.30 0.98267 11.76 9.44 9.28 198870 6 80 5.4S 5.37 0.98560 9 30 7.45 7.34 0.98261 11.80 9.48 9.31 :.9SS64 6 85 547 5.41 0.98554 935 7.49 7.38 0.98255 11.86 9.52 9.35 9S857 6 90 5.51 5.45 0.98549 9 40 7.53 7.42 0.98250 11.90 9.56 9.39 OSS.jI 6 95 5.55 5.49 0.98543 9 45 7.57 7.46 0.98244 11 95 9.60 9.43 assK") 7 00 5.59 5.53 0.98537 9.50 7.61 7.50 0.98238 12 00 9.64 9.47 S7f;3 7 65 6.11 6.04 0.98457 10.15 8.14 8.01 0.98162 12.65 10.17 9.99 !'S7r)G 7 70 6.15 6.08 0.98452 10.20 8.18 8.05 0.98156 12 70 10.21 10.03 9S750 7 75 6.19 6.12 0.98446 10.25 8.22 8.09 0.98150 12.75 10.25 10.07 98744 7 80 6.U 6.16 0.98441 10.30 8.26 8.13 0.98145 12 80 10.29 10 10 98738 7.85 6.28 6.20 0.98435 10 35 8.30 8.17 0.98139 12 86 10.33 10.14 'K731 7 90 6.32 6.24 0.98428 10 40 8.34 8.21 0.98132 12 90 10.38 10.18 MS7_'.') 7 95 6.36 6.28 0.98422 10.45 8.38 8.25 0.98127 12 96 10.42 10.22 198718 8 00 6.40 6.32 0.98416 10.50 8.42 8.29 0.98122 13 00 10.46 10.26 98712 8 05 6.44 6.36 0.98410 10.55 8.46 8.33 0.98116 13 05 10.50 10.30 '98700 8 10 6.48 6.39 0.98404 10 60 8.50 8.37 0.98111 13 10 10.54 10.34 '98700 8 15 6.52 6.43 0.98398 10.66 8.64 8.41 0.98105 13 15 10.58 10.38 '98694 8 20 6.56 6.47 0.98391 10.70 8.58 8.45 0.98100 13 20 10.62 10.42 '.ISIiSS 8 25 6.60 6.51 0.98385 10.75 8.62 8.49 0.98094 13 25 10.66 10.46 9StiS'J 8 30 6.64 6.55 0.98379 10.80 8.66 8.52 0.98089 13 30 10.70 10.50 '9S676 8 35 6.68 6.59 0.98373 10 85 8.70 8.56 0.98083 13 35 10.74 10.54 ''98670 8 40 6.72 6.63 0.98368 10.90 8.75 8.60 0.98077 13 40 10.78 10 58 '98664 8 45 6.76 6.67 0.98362 10.95 8.79 8.64 0.98071 13 45 10.82 10.62 i9Sr,,-)S 8 50 6.80 6.71 0.98356 11.00 8.83 8.68 0.98066 13 50 10.86 10.66 i9Sti.">'J 8 55 6.84 6.75 0.98350 11.06 8.87 8.72 0.98060 13 56 10.90 10.70 t9864t> 8 60 6.88 6.79 0.98344 11.10 8.91 8.76 0.98054 13 60 10.95 10.74 198640 8 65 6.92 6.83 0.98338 11.16 8.95 8.80 0.98048 13 66 10.99 10.78 i;98G33 8 70 6.96 6.87 0.98332 11.20 8.99 8.84 0.98043 13 70 11.03 10.81 ^98627 8 75 7.00 6.91 0.98326 11 26 9.03 8.88 0.98037 13 76 11.07 10.85 08620 8 80 7.04 6.95 0.98320 W 30 9.07 8.92 0.98031 13 80 //./; 10.89 (198614 8 85 7.08 6.99 0.98314 11.36 9.11 8.96 0.98025 13 85 11.15 10.93 l|9S60S 8 90 7.12 7.03 0.98308 11.40 9.15 9.00 0.9S020 13 90 11.19 10.97 (98602 8 95 7.16 7.07 0.98302 11.46 9.19 9.04 0.98014 13 95 11.23 11.01 ('98596 9 00 7.20 7.10 0.98296 11 60 9.23 9.08 0.98009 14 00 11.28 11.05 (9S590 9 05 7.24 7.14 0.98290 11.65 9.27 9.12 0.98003 14 05 11.32 11.09 ()SnS4 9 10 7.29 7.18 0.98285 11.60 9.32 9.16 0.97998 14 10 11.36 11.13 ns.-,7S 9 15 7.33 7 22 0.98279 11.66 9.36 9.20 0.97992 14.15 11.40 11.17 "'_ 9 20 7.37 7^26 0.98273 11.70 9.40 9.24 0.97986 14.20 11. U 11.21 196 METHODS OF ANALYSIS [Chap. 5 Table 16.— Alcohol Table.- -Continued. ALCOHOL ALCOHOL ALCOHOL SPECIFIC SPECIFIC SPECIFIC GRAVITY 20° C. Per cent Per Grama °Iqo^^ Per cent Per Grams °2(r'^a^ Per cent Per Grai 4° by volume cent by per 4° by volume cent by per 4° by volume cent by pe at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 0.97980 14 25 11.48 11.25 0.97704 16.75 13.53 13.22 0.97438 19 26 15.59 15. 0.97975 14.30 11.52 11.29 0.97699 16 80 13.57 13.26 0.97433 19 30 15.64 15. 0.97969 14 35 11.56 11.33 0.97694 16.85 13.61 13.30 0.97428 19 35 15.68 15. 0.97964 14 40 11.60 11.37 0.97689 16.90 13.66 13.34 0.97423 19 40 15.72 15. 0.97958 14 45 11.64 11.41 0.97683 16 95 13.70 13.38 0.97417 19.45 15.76 15. 0.97953 14.50 11.68 11.44 0.97678 17 00 13.74 13.42 0.97412 19 50 15.80 15. 0.97947 14.55 11.72 11.48 0.97672 17.05 13.78 13.46 0.97407 19.55 15.84 15. 0,97942 14 60 11.77 11.52 0.97667 17.10 13.82 13.50 0.97402 19.60 15.88 15. 0.97936 14 65 11.81 11.56 0.97661 17 15 13.86 13.54 0.97396 19.65 15.92 15. 0.97930 14.70 11.85 11.60 0.97656 17.20 13.90 13.58 0.97391 19.70 15.97 15. 0.97924 14.75 11.89 11.64 0.97650 17.25 13.94 13.62 0.97386 19.75 16.01 15. 0.97919 14 80 11.93 11.68 0.97645 17 30 13.98 13.66 0.97381 19.80 16.05 15. 0.97913 14 85 11.97 11.72 0.97639 17 35 14-02 13.70 0.97375 19 85 16.09 15. 0.97908 14 90 12.01 11.76 0.97634 17.40 14-07 13.74 0.97370 19.90 16.13 15.' 0.97902 14.95 12.05 11.80 0.97629 17.45 14-11 13.78 0.97364 19 95 16.17 15.' 0.97897 15 00 12.09 11.84 0.97624 17.50 14-15 13.81 0.97359 20 00 16.21 15.' 0.97891 15 05 12.13 11.88 0.97618 17.55 14-19 13.85 0.97354 20.05 16.25 15. { 0.97885 15.10 12.18 11.92 0.97613 17.60 14-23 13.89 0.97349 20.10 16.30 15. J 0.97879 15 15 12.22 11.96 0.97607 17.65 14-27 13.93 0.97344 20.15 16.34 15. < 0.97874 15 20 12.26 12.00 0.97602 17.70 14-31 13.97 0.97339 20.20 16.38 15. < 0.97868 15 25 12.30 12.04 0.97596 17.75 14-35 14.01 0.97333 20 26 16.42 15.< 0.97863 15 30 12.34 12.08 0.97591 17.80 14-40 14.05 0.97328 20.30 16.46 16.( 0.97857 15 35 12.38 12.12 0.97586 17.85 14-44 14.09 0.97322 20 35 16.50 16.( 0.97852 15 40 12.42 12.16 0.97581 17 90 U-48 14.13 0.97317 20.40 16.55 16. 0.97846 15 45 12.46 12.20 0.97575 17 95 14.52 14.17 0.97311 20.45 16.59 16. 0.97841 15 50 12.50 12.23 0.97570 18 00 14-56 14.21 0.97306 20 50 16.63 16. 0.97835 15 55 12.54 12.27 0.97564 18.05 14-60 14.25 0.97300 20.55 16.67 16.i 0.97830 15 60 12.59 12.31 0.97559 18.10 14-64 14.29 0.97295 20 60 16.71 16.5 0.97824 15 65 12.63 12.35 0.97553 18.15 14-68 14.33 0.97289 20 65 16.75 16.; 0.97819 15.70 12.67 12.39 0.97548 18 20 14-73 14.37 0.97284 20.70 16.80 16.; 0.97813 15 75 12.71 12.43 0.97542 18 25 14-77 14.41 0.97278 20 76 16.84 16.; 0.97808 15 80 12.75 12.47 0.97538 18 30 14-81 14.45 0.97273 20 80 16.88 16.^ 0.97802 15 85 12.79 12.51 0.97532 18.35 14-85 14.49 0.97268 20 85 16.92 16.^ 0.97797 15 90 12.83 12.55 0.97527 18.40 14-89 14.52 0.97263 20 90 16.96 16.. 0.97791 15 95 12.87 12.59 0.97522 18 45 14-93 14.56 0.97257 20 95 17.00 16.. 0.97786 16 00 12.92 12.63 0.97517 18.50 14-97 14.60 0.97252 21.00 17.04 16.. 0.97780 16 05 12.96 12.67 0.97512 18 55 15.01 14.64 0.97247 21.05 17.08 16. ( 0.97775 16 10 13.00 12.71 0.97507 18 60 15.06 14.68 0.97242 21.10 17.13 16. 0.97769 16 15 13.04 12.75 0.97501 18 65 15.10 14.72 0.97237 21 15 17.17 16.' 0.97764 16 20 13.08 12.79 0.97496 18 70 15.14 14.76 0.97232 21 20 17.21 16. 0.97758 16.25 13.12 12.83 0.97490 18.75 15.18 14.80 0.97227 21 25 17.25 16. 0.97753 16 30 13.16 12.87 0.97485 18.80 15.22 14.84 0.97222 21 30 17.29 16.{ 0.97747 16 35 13.20 12.91 0.97479 18 85 15.26 14.88 0.97216 21 35 17.33 16. { 0.97742 16.40 13.24 12.95 0.97474 18.90 15.30 14.92 0.97210 21.40 17.38 16.{ 0.97737 16.45 13.28 12.99 0.97469 18 95 15.34 14.96 0.97204 21.45 17.42 16. 0.97732 16 50 13.33 13.02 0.97464 19.00 15.39 15.00 0.97199 21.50 17.46 16. 0.97726 16 55 13.37 13.06 0.97459 19 05 15.43 15.04 0.97193 21.55 17.50 17. 0.97721 16 60 13.41 13.10 0.97454 19 10 15.47 15.08 0.97188 21 60 17.54 17. 0.97715 16 65 13.45 13.14 0.97449 19.15 15.51 15.12 0.97183 21 65 17.58 17. 0.97710 16 70 13.49 13.18 0.97444 19 20 15.55 15.16 0.97178 21.70 17.63 17. XVI] WINES 197 Table 16.— Alcohol Table.— Continued. , „..„. .\LCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL Per cent Per Grams GRAVITY 20° C. Per rent Per Grams GR.WITY 20° C. Per cent Per Gram* by volume cent by per 4° by volume cent by per 4° by volume cent by per at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 cc. 7172 21 75 17.67 17.17 0.96896 24.25 19.75 19.14 0.96612 26.76 21.85 21.12 21 80 17.71 17,21 0.96801 24 30 19.80 19.18 0.96606 26 80 21.90 21.16 21 85 17.75 17.25 0.96885 24 35 19.84 19.22 0.96600 26 85 21.94 21.20 21 90 17.79 17.29 0.96880 24 40 19.88 19.26 0.06505 26 90 21.98 21.23 ;71o0 21 95 17.83 17.33 0.96874 24 45 19.92 19.30 0.96589 26 96 22.02 21.27 71 4o 22 00 17.88 17.37 0.96869 24 50 19.96 19.34 0.96583 27 00 22.07 21.31 7i:;'i 22 05 17.92 17.41 0.9&S63 24 55 20.00 19.38 0.06577 27 05 22.11 21.35 nil 22 10 17.96 17.45 0.96.S57 24 60 20.05 19.42 0.06571 27 10 22.15 21.39 22 15 18.00 17.49 0.90851 24 65 20.09 19.46 0.06505 27 16 22.19 21.43 71 L':! 22 20 18.04 17.52 0.96846 24 70 20.13 19.50 0.06559 27 20 22.24 21.47 ,711S 22 25 18.08 17.56 0.96840 24 75 20.17 19.54 0.96553 27 26 22.28 21.51 !7li:^ 22 30 18.13 17.60 0.96.S35 24 80 20.22 19.58 0.06548 27 30 22.32 21.55 17107 22 35 18.17 17.64 0.96820 24 86 20.26 19.62 0.96542 27 36 22.36 21.59 7102 22 40 18.21 17.68 0.96823 24 90 20.30 19.66 0.96536 27 40 22.40 21.63 7006 22 45 18.25 17.72 0.96817 24 95 20.34 19.70 0.96530 27 45 22.44 21.67 7001 22 50 18.29 17.76 0.96812 25 00 20.38 19.73 0.96525 27 50 22.49 21.71 70^5 22 55 18.33 17.80 0.96806 26 05 20.42 19.77 0.96519 27 56 22.53 21.75 7lK0 22 60 18.38 17.84 0.96801 25 10 20.47 19.81 0.96513 27 60 22.57 21.79 - - ; 22 65 18.42 17.88 0.96795 25 15 20.51 19.85 0.96.507 27.66 22.61 21.83 ' 22 70 18.46 17.92 0.96789 25.20 20.55 19.89 0.96501 27.70 22.66 21.87 706.S 22 75 18.50 17.96 0.96783 26 25 20.59 19.93 0.96495 27.76 22.70 21.91 70."i.^ 22 80 18.54 18.00 0.96778 25 30 20.64 19.97 0.964,S9 27 80 22.74 21.94 70.-i2 22 85 18.58 18.04 0.96772 25 35 20.68 20.01 0.06483 27 85 22.78 21.98 7047 22 90 18.63 18.08 0.96766 25 40 20.72 20.05 0.96477 27 90 22.83 22.02 7011 22 95 18.67 18.12 0.96760 26.46 20.76 20.09 0.96471 27 95 22.87 22.06 23 00 18.71 18.16 0.96755 25 60 20.80 20.13 0.96465 28 00 22.91 22.10 ,M 23 05 18.75 18.20 0.96749 26 65 20.84 20.17 0.96459 28 05 22.95 22.14 7()j:) 23 10 18.79 18.24 0.96744 25 60 20.89 20.21 0.96454 28 10 23.00 22.18 7010 23 15 18.83 18.28 0.96738 25 66 20.93 20.25 0.9644S 28 15 23.04 22 22 701 :i 23 20 18.88 18.31 0.96733 25 70 20.97 20.29 0.96442 28 20 23.08 22^26 23 25 18.92 18.35 0.96727 25 76 21.01 20.33 0.96436 28.25 23.12 22.30 23 30 18.96 18.39 0.96722 26 80 21.06 20.37 0.96430 28 30 23.17 22.34 23 35 19.00 18.43 0.96716 26 85 21.10 20.41 0.96424 28 35 23.21 22.38 ./111 23 40 19.04 18.47 0.96710 26 90 21.14 20.44 0.96418 28 40 23.25 22 42 23 45 19.08 18.51 0.96704 26 96 21.18 20.48 0.96412 28.45 23.29 22^46 1 23 50 19.13 18.55 0.96699 26 00 21.22 20.52 0.96406 28 50 23.33 22.50 1 23 55 19.17 18.59 0.96693 26 05 21.26 20.56 0.96400 28 56 23.37 22.54 1 23 60 19.21 18.63 0.96687 26 10 21.31 20.60 0.96393 28 60 23.42 22.57 23 65 19.25 18.67 0.96681 26 15 21.35 20.64 0.96387 28 65 23.46 22.61 1 605S 23 70 19.29 18.71 0.96675 26 20 21.39 20.68 0.96381 28 70 23.51 22.65 ) 6052 23 75 19.33 18.75 0.96669 26 26 21.4S 20.72 0.96375 28 76 23.55 22.69 )6947 23 80 19.38 18.79 0.96664 26 30 21.48 20.76 0.96369 28 80 23.59 22.73 )6941 23 85 19.42 18.83 0 96658 26 35 21.52 20.80 0.96363 28 85 23.63 22.77 ) 6936 23 90 19.46 18.87 0.96653 26 40 21.56 20.84 0.96357 28 90 23.67 22.81 3 6930 23 95 19.50 18.91 0.96647 26 45 21.60 20.88 0.96351 28 96 23.71 22.85 Vr,OL\-, 24 00 19.55 18.94 0.96641 26 50 21.64 20.92 0.90346 29 00 23.76 22.89 24 05 19.59 18.08 0.96635 26 56 21.68 20.96 0.96340 29 05 23.80 22.93 24 10 19.63 19.02 0.96680 26.60 81.73 21.00 0 96334 29 10 23.84 22.97 7 24 15 19.67 19.06 0.96624 26 65 21.77 21.04 0 9632S 29.15 23.88 23.01 24 20 19.71 19.10 0.96618 26 70 21.81 21. OS 0.96322 29 20 23.93 23.05 198 METHODS OF ANALYSIS [Chap. 5 Table 16.— Alcohol Table.- —Continued. SPECIFIC .VLCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL GRAVITY 20° C. Per cent Per Grams "20^"^ Per cent Per Grams 26° C. Per cent Per Gra -40 by volume cent by per 4° by volume cent by per 4° by volume cent by P« at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 0.96316 29.25 23.97 23.09 0.96005 31.76 26.10 25.06 0.95669 34.26 28.26 27 0.96310 29 30 24 01 23.13 0.95998 31.80 26.15 25.10 0.95662 34.30 28.30 27 0 . 96304 29 35 24.05 23.17 0.95992 31.86 26.19 25.14 0.95655 34.35 28.34 27 0 96297 29 40 24.10 23.21 0.95985 31 90 26.23 25.18 0.95648 34 40 28.39 27 0.96291 29.45 24 -U 23.25 0.95979 31.95 26.27 25.22 0.95641 34 46 28.43 27 0.96285 29 50 24.1s 23.29 0.95972 32 00 26.32 25.26 0.95634 34.50 28.48 27 0 . 96279 29 55 24-22 23.33 0.95965 32 05 26.36 25.30 0.95627 34.65 28.52 27 0 96273 29 60 24.27 23.36 0.95958 32 10 26.41 25.34 0.95619 34 60 28.56 27 0.96267 29 65 24.31 23.40 0.95952 32 15 26.45 25.38 0.95612 34.65 28.60 27 0.96261 29.70 24.35 23.44 0.95945 32 20 26.49 25.42 0.95605 34.70 28.65 27 0.96255 29 76 24.39 23.48 0.95939 32 26 26.53 25.46 0.95598 34.76 28.69 27 0.96248 29 80 2 A. 44 23.52 0.95932 32 30 26.58 25.50 0.95591 34 80 28.74 27 0.96242 29 85 24.48 23.56 0.95926 32.35 26.62 25.54 0.95584 34 85 28.78 27 0.96236 29 90 24.52 23.60 0.95920 32.40 26.66 25.58 0.95577 34 90 28.82 27 0.96230 29.95 24.56 23.64 9.95913 32.46 26.70 25.61 0.95570 34.95 28.86 27 0 . 96224 30 CO 24. 61 23.68 0.95906 32.50 26.75 25.64 0.95563 36 00 28.91 27 0 96218 30 05 24.65 23.72 9.95900 32.55 26.79 25.68 0.95556 35 05 28.95 27 0.96211 30 10 24.69 23.76 0.95893 32 60 26.83 25.72 0.95549 35.10 29.00 27 0.96205 30 15 24.73 23.80 0.95887 32 65 26.87 25.76 0.95542 35.16 29.04 27 0.96199 30.20 24.78 23.84 0.95880 32.70 26.92 25.80 0.95535 36.20 29.08 27 0.96193 30 25 24.82 23.88 0.95873 32.75 26.96 25.84 0.95528 36 25 29.12 27 0.96187 30 30 24.87 23.92 0.95866 32.80 27.01 25.89 0.95521 35.30 29.17 27 0.96181 30 35 24.91 23.96 0.95859 32.85 27.05 25.93 0.95513 36 35 29.21 27 0.96175 30 40 24.95 24.00 0.95852 32 90 27.09 25.97 0.95506 35.40 29.26 27 0.96169 30.45 24.99 24.04 0.95846 32 96 27.13 26.01 0.95499 35.45 29.30 27 0.96163 30 50 25.04 24.08 0.95839 33.00 27.18 26.05 0.95492 35.60 29.34 28 0.96157 30 55 25.08 24.12 0.95833 33.06 27.22 26.09 0.95485 35 56 29.38 28 0 96150 30.60 25.12 24.15 0.95826 33 10 27.27 26.13 0 95478 35 60 29.43 28 0.96141 30 65 25.16 24.19 0.95819 33 16 27.31 26.17 0.95470 35 65 29.47 28 0.96138 30.70 25.21 24.23 0.95812 33 20 27.35 26.21 0.95463 35.70 29.52 28 0.96132 30.75 25.25 24.27 0.95806 33 25 27.39 26.25 0.95456 35.76 29.56 28 0.96125 30 80 25.30 24.31 0.95799 33 30 27.44 26.29 0.95449 36.80 29.61 2S 0.96119 30 85 25.34 24.35 0.95792 33 35 27.48 26.33 0.95441 35.86 29.65 28 0 96112 30 90 25.38 24.39 0.95785 33 40 27.52 26.36 0.95434 35 90 29.69 28 0.96106 30 95 25.42 24.43 0.95778 33.45 27.56 26.40 0.95426 36.95 29.73 28 0.96100 31 00 25.46 24.47 0.95771 33.50 27.61 26.44 0.95419 36.00 29.78 28 0.96094 31.05 25.50 24.51 0.95764 33 55 27.65 26.48 0.95412 36.05 29.82 28 0.96088 31 10 25.55 24.55 0.95757 33.60 27.70 26.52 0.95405 36 10 29.87 28 0.96082 31.15 25.59 24.59 0.95751 33 65 27.74 26.56 0.95397 36.15 29.91 28 0.96075 31.20 25.63 24.63 0.95745. 33.70 27.78 26.60 0.95390 36.20 29.95 28 0.96069 31.25 25.67 24.67 0.95738 33 75 27.82 26.64 0.95382 36.25 29.99 28 0.96062 31.30 25.72 24.71 0.95731 33 80 27.87 26.68 0.95375 36 30 30.04 28 9.96056 31.35 25.76 24.75 0.95724 33.85 27.91 26.72 0.95367 36.35 30.09 28 0.96049 31.40 25.81 24.79 0.95717 33.90 27.96 26.76 0.95360 36.40 30.13 28 0.96043 31.46 25.85 24.83 0.95710 33.96 28.00 26.80 0.95353 36.46 30.17 28. 0.96036 31 60 25.89 24.86 0.95703 34 00 28.04 26.84 0.95346 36.60 30.22 28 0.96030 31.65 25.93 24.90 0.95696 34 05 28.08 26.88 0.95338 36.66 30.26 28. 0.96024 31.60 25.98 24.94 0.95689 34.10 28.13 26.92 0.95331 36.60 30.31 28 0.96018 31.66 26.02 24.98 0.95682 34.15 28.17 26.96 0.95323 36.66 30.35 28 0.98011 31.70 26.06 25.02 0.95675 34.20 28.22 26.99 0.95315 36.70 30.39 28 XVI] WINES 199 Table 16.— Alcohol Table.— Continued. ICIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL ..VITY •c. Per cent Per Grams 20° C. Per cent Per Grams CinAVITY 20° C. Per cent Per Grama ■o by volume cent by per 4° by volume cent by per 4° by volume cent by per at 20° C. weight 100 cc. at20°C. weight 100 cc. at 20° C. weight 100 cc. 0!53OS 36 75 SO. 43 29.01 0.94926 39 25 32.63 30.99 0.94519 41.76 34.86 32.96 0 5301 36 80 so 48 29.05 0.94918 39 30 32.68 31.02 0.94510 41 80 34-91 33.00 0 5294 36 85 SO. 52 29.09 0.94910 39 35 32.72 31.06 0.94502 41.85 34.95 33,04 0i5287 36 90 SO. 57 29.13 0.94901 39.40 32.77 31.10 0.94494 41.90 35.00 33,07 015279 36 95 SO. 61 29.17 0.94893 39.45 32.81 31.14 0.94486 41.96 35.04 33.11 015272 37 00 30.66 29.21 0.94885 39 50 32.86 31.18 0.94477 42.00 35.09 33.15 Di5264 37 05 30.70 29.25 0.94877 39.55 32.90 31.22 0.94469 42.05 35.13 33,19 05257 37 10 30.74 29.29 0.94869 39 60 32.95 31.26 0.94460 42.10 35.18 33,23 0 5249 37 15 30.78 29.33 0.94861 39 65 32.99 31.30 0.94452 42.16 35.22 33.27 0 5242 37 20 30.83 29.36 0.94853 39.70 S3. 04 31.34 0.94443 42.20 35.27 33.31 0I5234 37 25 30.87 29.40 0.94845 39 75 S3. 08 31.38 0.94435 42 25 35.31 33.35 )l5227 37 30 30.92 29.44 0.94837 39 80 33.13 31.42 0.94427 42 30 35.36 33.39 M5219 37 35 30.96 29.48 0.94829 39.85 33.17 31.46 0.94419 42 35 35.40 33.43 [^'5211 37.40 31.01 29.52 0.94821 39.90 33.22 31.50 0.94410 42.40 35.45 33.47 0C5203 37 45 SI. 05 29.56 0.94813 39.95 33.26 31.54 0.94402 42.45 35.49 33.51 45196 37.50 31.09 29.60 0.94805 40.00 33.30 31.57 0.94393 42 50 35.54 33.55 W5188 37 55 31.13 29.64 0.94797 40.05 SS.S4 31.61 0.94385 42 55 35.58 33.59 tt5181 37.60 31.18 29,68 0.94789 40.10 33.39 31.65 0.94376 42 60 35.63 33,63 D5173 37 65 31.22 29.72 0.94781 40.15 3S.4S 31.69 0.94368 42 65 35.67 33.67 0|»5166 37.70 31.27 29.76 0.94773 40.20 3S.48 31.73 0.94359 42.70 35.72 33.71 0 to 158 37 75 SI. 31 29.80 0.94765 40 25 33.52 31.77 0.94351 42.75 35.76 33.75 05151 37.80 31.36 29.84 0.94757 40.30 33.57 31.81 0.94342 42.80 35.81 33.78 (!t51 13 37 85 31. 40 29.88 0.94749 40 35 33.61 31.85 0.94334 42.85 35.85 33,82 rt.")!:;.') 37 90 31.45 29.92 0.94741 40 40 33.66 31.89 0.94325 42 90 35.90 33,86 (t:.iJ7 37 95 31.49 29.96 0.94733 40.45 33.70 31.93 0.94317 42.95 35.94 33.90 rt.ii'-'o 38 00 31.53 29.99 0.94725 40 60 SS.75 31.97 0.94308 43.00 35.99 33.94 Of) 11 2 38 05 SI. 57 30.03 0.94717 40 55 33.79 32.01 0.94300 43 05 36.03 33.98 05104 38 10 31.62 30.07 0.94708 40 60 33.84 32.05 0.94291 42.10 36.08 34.02 05090 38 15 31.66 30.11 0.94700 40 65 33.88 32.09 0.94283 43.15 36.12 34.06 C)50S9 38 20 31.71 30.15 0.94692 40.70 33.93 32.13 0.94274 43 20 36.17 34.10 (t50si 38 25 31.75 30.19 0.94684 40 75 SS.97 32.17 0.94265 43.26 36.21 34.14 ( t.ior 4 38 30 31.80 30.23 0.94676 40.80 34.02 32.20 0.94256 43 30 36.26 34.18 (»50C.() 38 35 31.84 30.27 0.94668 40.85 34.06 32.24 0.94248 43 36 36 SO 34,22 ( )5o:)X 38 40 SI. 89 30.31 0.94659 40 90 34-11 32.28 0.94239 43 40 36 35 34,26 ()50.')0 38 45 31.93 30.35 0.94651 40.95 34.15 32.32 0.94231 43.45 36.39 34.30 ( t.')!)):; 38 50 31.97 30.39 0.94643 41 00 34.19 32.36 0.94222 43 60 36.44 34.34 ( >.■)():',.") 38 55 32.01 30.43 0.94635 41 05 34.23 32.40 0.94214 43 55 36.48 34.38 O5027 38 60 32.06 30.47 0.94627 41 10 34.28 32.44 0,04205 43 60 S>:.53 34.42 05019 38 65 32.10 30.51 0.94619 41 15 34-32 32.48 0.94197 43 65 36.57 34.46 n:,n 11 38 70 32.15 30.55 0.94610 41 20 34-37 32.52 0.94188 43 70 36.62 34.49 1 iriOi )■; 38 75 32.19 30.59 0.94602 41 25 34.41 32.56 0.94179 43 75 36.66 34.53 ( Mit'.tO 38.80 32.24 30.63 0.94594 41 30 S4-46 32.60 0,94170 43 80 36.71 34.57 ( )49SS 38 85 32.28 30.67 0.94586 41 35 34-50 32.64 0,94161 43 85 S6 . 75 34.61 CM!tS() 38 90 32.33 30.71 0.94577 41 40 34-55 32.68 0.94152 43 90 36.80 34.65 C|)4972 38 95 32. S7 30.75 0.94569 41.46 34.59 32.72 0,94144 43 95 36.84 34 69 04904 39 00 32.42 30.79 0.94560 41 60 34-64 32.76 0,94135 44 00 36.89 34.73 049:,(; 39 05 32.46 30.83 0.94552 41 56 S4-68 32.80 0,94126 44 05 36.94 34.77 ft494() 39 10 32.51 30.87 0.94544 41.60 34-73 32.84 0.94117 44 10 36.99 34.81 U4941 Cj)4934 39.15 32.55 30.91 0.94536 41 65 34.77 32.88 0.9410S 44.15 37.03 34.85 39 20 32.59 30.95 0.94527 41.70 S4.82 32.92 0.94099 44 20 37.08 34.89 200 METHODS OF ANALYSIS [Chap. 5 Table 16.— Alcohol Table.- —Continued. SPECIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL °20°''c.'' Per cent Per Grams *'20°''c.^ Per cent Per Grams ''w^c^ Per cent Per Gra 4° by volume cent by per 4° by volume cent by per 4° by volume cent by pe at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 0.94091 44.25 37.12 34.93 0.93638 46 75 39.41 36.90 0.93164 49.26 41.72 38. 0.94082 44 30 37.17 34.97 0.93629 46 80 39.46 36.94 0.93155 49 30 41.77 38. 0.94073 44.35 37.21 35.01 0.93619 46 85 39.50 36.98 0.93145 49 35 41.82 38. 0.94064 44.40 37.26 35.05 0.93610 46 90 39.55 37.02 0.93136 49.40 41.87 38. 0.94055 44.45 37.30 35.09 0.93600 46 95 39.59 37.06 0.93126 49.45 41.91 39. 0.94046 44 50 37.35 35.13 0.93591 47.00 39.64 37.10 0.93116 49 50 41.96 39. 0.94037 44.55 37.39 35.17 0.93582 47.05 39.68 37.14 0.93106 49.55 42.01 39. 0.94028 44.60 37. U 35.20 0.93573 47.10 39.73 37.18 0.93096 49.60 42.06 39. 0.94020 44.65 37.48 35.24 0.93563 47.15 39.77 37.22 0.93086 49.65 42.10 39. 0.94011 44.70 37.53 35.28 0.93554 47.20 39.82 37.26 0.93076 49.70 42.15 39. 0.94002 44.75 37.57 35.32 0.93545 47.25 39.87 37.30 0.93066 49 75 42.19 39. 0.93993 44 80 37.62 35.36 0.93536 47 30 39.92 37.34 0.93056 49 80 42.24 39. 0.93984 44.85 37.66 35.40 0.93526 47 35 39.96 37.38 0.93046 49 85 42.29 39. 0.93975 44 90 37.71 35.44 0.93517 47.40 40.01 37.42 0.93036 49 90 42.34 39. 0.93966 44.95 37.75 35.48 0.93507 47.45 40.05 37.46 0.93026 49 95 42.38 39. 0.93957 45 00 37.80 35.52 0.93498 47 50 40.10 37.49 0.93017 50 00 42.43 39. 0.93948 45.05 37.85 35.56 0.93488 47 55 40.14 37.53 0.93007 50 05 42.47 39. 0.93939 45.10 37.90 35.60 0.93479 47.60 40.19 37.57 0.92997 50.10 42.52 39. 0.93931 45.15 37.94 35.64 0.93470 47.65 40.24 37.61 0.92987 50 15 42.57 39. 0.93922 45.20 37.99 35.68 0.93461 47.70 40.29 37.65 0.92977 50.20 42.62 39. 0.93912 45 25 38.03 35.72 0.93451 47.75 40.33 37.69 0.92967 60 25 42.66 39. 0.93903 45 30 38.08 35.76 0.93442 47.80 40.38 37.73 0.92957 50 30 42.71 39. 0.93894 45.35 38.12 35.80 0.93432 47.85 40.42 37.77 0.92947 50 35 42.76 39. 0.93885 45.40 38.17 35.84 0.93423 47.90 40.47 37.81 0.92938 50 40 42.81 39. 0.93876 45.45 38.21 35.88 0.93413 47.95 40.51 37.85 0.92928 60.46 42.85 39. 0.93867 45 50 38.26 35.92 0.93404 48 00 40.56 37.89 0.92918 50 60 42.90 39. 0.93858 45 55 38.30 35.86 0.93394 48 05 40.61 37.93 0.92908 60.56 42.94 39. 0.93849 45 60 38.35 35.99 0.93385 48 10 40.66 37.97 0.92898 60 60 42.99 39. 0.93840 45 65 38.39 36.03 0.93375 48.15 40.70 38.01 0.92888 50 65 43.04 39. 0.93831 45.70 38.44 36.07 0.93366 48.20 40.75 38.05 0.92879 50.70 43.09 40. 0.93822 45.76 38.49 36.11 0.93356 48.25 40.79 38.09 0.92869 50 76 43.13 40. 0.93813 45.80 38.54 36.15 0.93347 48 30 40.84 38.13 0.92859 60 80 43.18 40. 0.93803 45.85 38.58 36.19 0.93337 48 35 40.89 38.17 0.92849 50 85 43.23 40. 0.93794 45.90 38.63 36.23 0.93328 48 40 40.94 38.21 0.92839 50 90 43.28 40. 0.93785 45.95 38.67 36.27 0.93318 48.45 40.98 38.25 0.92829 50 96 43.32 40. 0.93776 46 00 38.72 36.31 0.93308 48.50 41.03 38.29 0.92818 61 00 43.37 40. 0.93767 46 05 38.76 36.35 0.93298 48 65 41.07 38.33 0.92808 51 06 43.42 40. 0.93758 46.10 38.81 36.39 0.93289 48 60 41.12 38.36 0.92798 51.10 43.47 40. 0.93749 46.15 38.85 36.43 0.93279 48 65 41.16 38.40 0.92788 51.15 43.51 40. 0.93740 46.20 38.90 36.47 0.93270. 48.70 41.21 38.44 0.92778 51 20 43.56 40. 0.93730 46 25 38.95 36.51 0.93260 48.75 41.26 38.48 0.92768 51 25 43.60 40. 0.93721 46 30 39.00 36.55 0.93251 48 80 41.31 38.52 0.92759 51 30 43.65 40. 0.93712 46 35 39.04 36.59 0.93241 48.85 41.35 38.56 0.92749 51 35 43.70 40. 0.93703 46 40 39.09 36.63 0.93232 48.90 41.40 38.60 0.92739 61 40 43.75 40. 0.93693 46.45 39.13 36.67 0.93222 48.95 41.44 38.64 0.92729 51.46 43.79 40. 0.93684 46 50 39.18 36.70 0.93213 49 00 41.49 38.68 0.92719 51 60 43.84 40. 0.93675 46.55 39.22 36.74 0.93203 49.05 41.54 38.72 0.92709 61.56 43.89 40. 0.93666 46.60 39.27 36.78 0.93194 49 10 41.59 38.76 0.92699 51.60 43.94 40. 0.93656 46.65 39.31 36.82 0.93184 49.15 41.63 38.80 0.92689 51 66 43.98 40. 0.93647 46.70 39.36 36.86 0.93174 49 20 41.68 38.83 0.92678 51.70 44.03 40. XVI] WINES 201 Table 16.— Alcohol Table.— Continued. ALCOHOL ALCOHOL lLCOHOL ■%C1FIC SPECIFIC SPECIFIC 6.VITY }° c. Per cent Per Grams GRAVITY 20° C. Per cent Per Grama 20° C. Per cent Per Grama by volume cent by per 4° by volume cent by per 4° by volume cent by per r at 20° C. weight 100 cc. at20°C. weight 100 cc. at 20° C. weight 100 cc. 0^2668 61.75 U08 40.85 0.92157 64 26 46.46 42.82 0.91629 56 75 48.89 44,80 02658 51 80 U.15 40.89 0.92147 54 30 46.51 42.86 0.91618 56 80 48.94 44,83 0 2648 51 85 U.17 40.93 0.92137 54 36 46.56 42.90 0.91608 56 85 48.98 44,87 02637 51 90 U.22 40.97 0.92126 64 40 46.61 42.94 0.91597 56 90 49.03 44.91 0!2627 51 95 U.26 41.01 0.92116 64.45 46.66 42.98 0.91586 66.96 49.08 44.95 02617 52 00 U.Sl 41.05 0.92105 54.60 46.71 43.02 0.91575 57 00 49.13 44.99 i _'('i07 62 05 U.S6 41.09 0.92095 64 65 46.75 43.06 0.91565 57 06 49.18 45.03 ) -'.V.i7 52 10 U41 41.13 0.92084 64 60 46.80 43.10 0.91554 57 10 49.23 45.07 012587 52 15 U46 41.17 0.92074 64.65 46.85 43.14 0.91543 57.15 49.28 45.11 0|2577 62 20 U.51 41.20 0.92063 64 70 46.90 43.18 0.91532 67.20 49.33 45.15 1 2507 52 26 U.55 41.24 0.92053 54.76 46.94 43.22 0.91521 67 26 49.38 45.19 52 30 U.60 41.28 0.92042 54 80 46.99 43.26 0.91510 67 30 49.43 45.23 1 ir,\7 62 36 U.65 41.32 0.92032 64 85 47.04 43.30 0.91500 57 35 49.47 45.27 52 40 U.70 41.36 0.92021 64 90 47.09 43.34 0.91489 67 40 49.52 45.31 1 .':.L'7 62 46 U.7i 41.40 0.92011 54 95 47.14 43.38 0.91478 57.46 49.57 45.35 0 2516 62 50 U-79 41,44 0.92000 65 00 47.19 43.42 0.91467 67 50 49.62 45.39 0 2506 52 55 UM 41.48 0.91990 56 06 47.24 43.46 0.91457 67 55 49.67 45.43 0 2406 52 60 U.89 41.52 0.91979 65 10 47.29 43.49 0.91446 57.60 49.72 45.47 ) :IS(i 52 65 U.93 41.56 0.91969 55.16 47.33 43.53 0.91435 67 66 49.77 45.51 i .' 176 52 70 U.98 41.60 0.91958 65.20 47.38 43.57 0.91424 57.70 49.82 45.55 0.2466 52 75 45.03 41.64 0.91948 56 26 47.43 43.61 0.91414 57.76 49.87 45.59 0.2455 52 80 45.08 41.68 0.91937 55 30 47.48 43.65 0.91403 67.80 49.92 45.63 0.2445 52 86 45.12 41.72 0.91927 65 36 47.53 43.69 0.91392 57.86 49.96 45.67 0 2434 52 90 45.17 41.76 0.91916 56 40 47.58 43.73 0.91381 57 90 50.01 45.70 0 2424 52 96 45.22 41.80 0.91906 65 46 47.62 43.77 0.91370 57.95 50.06 45.74 _M! I 53 00 45.27 41.83 0.91895 65 60 47.67 43.81 0.91359 58.00 50.11 45.78 .'inl 63 05 45.31 41.87 0.91885 56 55 47.72 43.85 0.91348 58 05 50.16 45.82 ' 1 53 10 45.36 41.91 0.91874 55 60 47.77 43.89 0.91337 58 10 50.21 45.86 1 53 16 45.41 41.95 0.91864 56 66 47.82 43.93 0.91326 58 15 50.26 45.90 63 20 45.46 41.99 0.91853 56.70 47.87 43.97 0.91315 68 20 50.31 45.94 53 26 45.51 42.03 0.91842 55 75 47.91 44.01 0.91304 68.26 50.36 45.98 53 30 45.56 42.07 0.91831 66.80 47.96 44.04 0.91293 68 30 50.41 46.02 53 35 45.60 42.11 0.91821 65 85 48.01 44.08 0.91282 58 36 50.46 46,06 53 40 45.65 42.15 0.91810 66 90 48.06 44.12 0.91271 58 40 50.51 46.10 53 46 45.70 42.19 0.91800 55 95 48.11 44.16 0.91261 58.45 50.55 46.14 53 50 45.75 42.23 0.91789 56 00 48.16 44.20 0.91250 68 60 50.60 46.17 53 55 45.79 42.27 0.91779 56.06 48.20 44.24 0.91239 68 55 50.65 46.21 53 60 45.84 42.31 0.91768 56 10 48.25 44.28 0.91228 58.60 50.70 46.25 ! 53 65 45.89 42.35 0.91758 56 15 48.30 44.32 0.91217 58 65 50.75 46.29 ^■71 53 70 45.94 42.39 0.91747 56 20 48.35 44.36 0.91206 58.70 50.80 46.33 '■-.] 53 76 45.98 42.43 0.91736 56 25 48.40 44.40 0.91194 58.75 50.85 46.37 ', 63 80 46.03 42.47 0.91725 56 30 48.45 44.44 0.91183 58 80 50.90 46.41 1 53 85 46.08 42.51 0.91715 56 35 48.50 44.48 0.91171 58 85 50.95 46.45 ' ::) 53.90 46.13 42.55 0.91704 56 40 48.55 44.52 0.91160 58 90 51.00 46.49 O.|;220 63 96 46.18 42.59 0.91694 56 45 48.59 44.56 0.91149 58 95 51.05 46.53 11 >ona 54 00 46.23 42.62 0.91683 66 50 48.64 44.60 0.91138 59 00 51.10 46.57 ,..,, 54 06 46.27 42.66 0.91672 56 55 48.69 44.64 0,91127 59 05 51.15 46.61 64 10 46.32 42.70 0.91661 56.60 48.74 44.68 0.91116 59.10 51.20 46.65 u A is 64.15 46.36 42.74 0.91650 56 65 48.79 44.72 0.91104 59.15 51.25 46.69 0.|J167 64.20 46.41 42.78 0.91639 56.70 48.84 44.76 0.91093 59 20 51.30 46.73 202 METHODS OF ANALYSIS [Chap. 5 Table 16.— Alcohol Table.- —Continued. SPECIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL 20° C. Per cent Per 1 Grams 20° C. Per cent Per Grams 20° C. Per cent Per Gn 4° by volume cent by per 4° by volume cent by per 4° by volume cent by P< at 20° C. weight 100 cc. at 20° C. weight 100 CO. at 20° C. weight 100 0.91082 59 26 51. S5 46.77 0.90520 61.75 53.85 48.74 0.89942 64.25 56.39 50 0.91071 59 30 5140 46.81 0.90509 61.80 53.90 48.78 0.89930 64 30 56.44 50 0.91060 59 36 5145 46.85 0.90497 61.85 53.95 48.82 0.89918 64.35 56.49 50 0.91049 59 40 51.50 46.89 0.90486 61.90 54.00 48.86 0.89907 64.40 56.54 50 0.91038 69 46 51.55 46.93 0.90474 61.96 54.05 48.90 0.89895 64.45 56.59 50 0.91027 59 60 51.60 46.97 0.90463 62 00 54.10 48.94 0.89884 64.50 56.64 50 0.91016 59 56 51.65 47.01 0.90451 62 05 54.15 48.98 0.89872 64 66 56.70 50 0.91005 69 60 51.70 47.05 0.90440 62.10 54.20 49.02 0.89861 64.60 56.75 50 0.90993 59 66 51.7J^ 47.09 0.90428 62.15 54.25 49.06 0.89849 64.66 56.80 51 0.90982 69 70 51.79 47.12 0.90417 62.20 54.30 49.10 0.89837 64.70 56.85 51 0.90971 59.75 51.84 47.16 0.90406 62 26 54.35 49.14 0.89825 64.75 56.90 51 0.90960 59 80 51.89 47.20 0.90395 62 30 54.40 49.18 0.89814 64.80 66.95 51 0.90949 59 85 51.94 47.24 0.90383 62 36 54.45 49.22 0.89802 64.85 57.00 51 0.90938 69 90 51.99 47.28 0.90372 62.40 54.50 49.25 0.89791 64.90 57.05 51 0.90926 59 95 52.04 47.32 0.90360 62.46 54.55 49.29 0.89779 64.95 57.11 51 0.90915 60 00 52.09 47.36 0.90349 62 50 5 4. 60 49.33 0.89767 65 00 57.16 51 0.90904 60 05 52.14 47.40 0.90337 62 55 54.66 49.37 0.89755 65 06 57.21 51 0.90893 60 10 52.19 47.44 0.90326 62 60 54.71 49.41 0.89744 65.10 57.26 51 0.90882 60 15 52.24 47.48 0.90314 62.65 54.76 49.45 0.89732 65.15 57.31 51 0.90871 60 20 52.29 47.52 0.90302 62 70 54. 81 49.49 0.89720 65.20 57.38 51 0.90859 60.25 52. S4 47.56 0.90290 62.76 54.86 49.53 0.89708 66 25 57.41 51 0.90848 60 30 52.39 47.60 0.90279 62 80 54.91 49.57 0.89696 65 30 57.46 51 0.90837 60 36 52.44 47.64 0.90267 62.85 54.96 49.61 0.89684 65 35 57.52 51 0.90826 60 40 52.49 47.68 0.90256 62.90 55.01 49.65 0.89672 65.40 57.57 51 0.90814 60 46 52.54 47.72 0.90244 62.95 55.06 49.69 0.89660 65 46 57.62 51 0.90803 60 50 52.59 47.76 0.90233 63 00 55.11 49.73 0.89649 65 50 57.67 51 0.90792 60 66 52.64 47.80 0.90221 63 05 55.16 49.77 0.89637 66 65 57.72 51 0.90781 60 60 52.69 47.84 0.90210 63 10 55.21 49.81 0.89626 65.60 57.77 51 0.90769 60 65 52.74 47.88 0.90198 63 15 55.26 49.85 0.89614 65.66 57.83 51 0.90758 60 70 52.79 47.91 0.90187 63.20 55.31 49.89 0.89602 66.70 57.88 51 0.90747 60 75 52.84 47.95 0.90175 63 26 55.37 49.93 0.89590 66 75 57.93 51 0.90736 60 80 52.89 47.99 0.90163 63 30 55.42 49.97 0.89578 65 80 57.98 51 0.90724 60 86 52.94 48.03 0.90151 63 35 55.47 50.01 0.89566 65.86 58.04 51 0.90713 60.90 52.99 48.07 0.90140 63 40 55.52 50.04 0.89554 65 90 58.09 52 0.90701 60 96 53.04 48.11 0.90128 63 45 55.57 50.08 0.89542 65 95 58.14 52 0.90690 61 00 53.09 48.15 0.90117 63 60 55.62 50.12 0.89531 66.00 58.19 52 0.90678 61 05 53.14 48.19 0.90105 63.55 55.67 50.16 0.89519 66.06 58.24 52 0.90667 61 10 53.19 48.23 0.90094 63 60 55.72 50.20 0.89507 66.10 58.29 52 0.90656 61 16 53.24 48.27 0.90082 63 65 55.77 50.24 0.89495 66 15 58.35 52 0.90645 61 20 53.29 48.31 0.90070 63 70 55.82 50.28 0.89483 66.20 58.40 52 0.90633 61 26 53.34 48.35 0.90059 63.75 55.88 50.32 0.89471 66.25 58.45 52 0.90622 61.30 53.39 48.39 0.90048 63 80 55.93 50.36 0.89459 66.30 58.50 52 0.90610 61 35 53.44 48.43 0.90036 63.85 55.98 50.40 0.89447 66 35 58.55 52 0.90599 61.40 53.49 48.47 0.90025 63.90 56.03 50.44 0.89435 66.40 58.60 52 0.90588 61 45 53.55 48.51 0.90013 63.96 56.08 50.48 0.89423 66.46 68.66 52 0.90577 61 50 53.60 48.55 0.90001 64.00 56.13 50.52 0.89411 66 50 58.71 52 0.90565 61.55 53.65 48.59 0.89989 64 05 56.18 50.56 0.89399 66 55 58.76 52 0.90554 61.60 53.70 48.62 0.89978 64.10 56.23 50.60 0.89387 66.60 68.81 52 0.90543 61.66 53.75 48.66 0.89966 64.15 56.29 50.64 0.89375 66.66 58.87 52 0.90532 61 70 53.80 48.70 0.89954 64.20 56.34 50.68 0.89363 66 70 68.92 52 XVI] WINES 203 Table 16.— Alcohol Table.— Continued. 1 5CIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL CAVITY !)°c. Per cent 1 Per Grams GRAVITY 20° C. Per cent Per Grams GRAVITY 20° C. Per cent Per Grams 1° by volume cent by per 4° by volume cent by per 4° by velum e cent by per at20°C. 1 weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 cc. p|{9351 66 75 58.97 52.69 0.88744 69 26 61.60 54.66 0.88120 71.75 64-27 56.64 19339 66 80 59.02 52.73 0.88732 69 30 61.65 54.70 0.88107 71 80 64.32 56.68 Ht9327 66 85 59.07 52.77 0.88720 69 35 61.70 54.74 0.88094 71 85 64.38 56.72 K9315 66 90 59.12 52.81 0.88707 69 40 61.75 54.78 0.88081 71 90 64-43 56.75 0^9303 66 95 59.18 52.85 0.88695 69 45 61.81 54.82 0.88069 71 95 64-49 56.79 0 9291 67 00 59.23 52.89 0.&S682 69 50 61.86 54.86 0.88056 72 00 64-54 56.83 0^9279 67 05 59.28 52.93 0.88670 69 55 61.92 54.90 0.88044 72 05 64-60 56.87 019267 67 10 59.33 52.97 0.88658 69 60 61.97 54.94 0.88031 72 10 64-65 56.91 019255 67 15 59.39 53.01 0.88646 69 65 62.02 54.98 0.88018 72 16 64-71 56.95 019243 67 20 59. A^ 53.04 0.88633 69.70 62.07 55.02 0.88005 72 20 64-76 56.99 [)i9231 67 25 59.49 53.08 0.88621 69 75 62.13 55.06 0.87993 72 25 64-82 57.03 09219 67 30 59.54 53.12 0.88608 69.80 62.18 55.10 0.87980 72 30 64-87 57.07 O!9207 67 35 59.60 53.16 0.88596 69 85 62.24 55.14 0.87967 72 36 64-93 57.11 D0195 B 19183 67 40 59.65 53.20 0.88583 69 90 62.29 55.18 0.87954 72 40 64.98 57.15 67 45 59.70 53.24 0.88571 69 95 62.34 55.22 0.87942 72 46 65.03 57.19 09171 67 60 59.75 53.28 0.88558 70.00 62.39 55.25 0.87929 72 60 65.08 57.23 09159 67 55 59.81 53.32 0.88546 70 06 62.45 55.29 0.87916 72 55 65.14 57.27 019147 67 60 59.86 53.36 0.88533 70 10 62.50 55.33 0.87903 72.60 65.19 57.31 019135 67 65 59.91 53.40 0.88521 70.15 62.56 55.37 0.87891 72 65 65.25 57.35 09122 67 70 59.96 53.44 0.88508 70 20 62.61 55.41 0.87878 72 70 65.30 57.38 O^llO 67 75 60.02 53.48 0.88496 70 26 62.66 55.45 0.87865 72 75 65.36 57.42 019098 67 80 60.07 53.52 0.88484 70 30 62.71 55.49 0.87852 72 80 65.41 57.46 0 9osr, 67 85 60.12 53.56 0.88472 70 36 62.77 55.53 0.87839 72 85 65.47 57.50 0 9074 67 90 60.17 53.60 0.88459 70 40 62.82 55.57 0.87826 72 90 65.52 57.54 09002 67 95 60.23 53.64 0.88447 70 46 62.87 55.61 0.87813 72 95 65.58 57.58 obooo 68 00 60.28 53.68 0.88434 70 60 62.92 55.65 0.87800 73 00 65.63 57.62 019038 68 05 60.33 53.72 0.88422 70 65 62.98 55.69 0.8VV88 73 05 65.69 57.66 0 9020 68 10 60.38 53.75 0.88409 70 60 63.03 55.73 0.87775 73 10 65.74 57.70 0 9O14 68 15 60. U 53.79 0.88397 70 65 63.09 55.77 0.87762 73 15 65.80 57.74 0 9OO1 68 20 60.49 53.83 0.88384 70.70 63.14 55.81 0.87749 73 20 65.85 57.78 0 B989 68 26 60.54 53.87 0.88372 70.76 63.20 55.85 0.87737 73 26 65.91 57.82 0 5977 68 30 60.59 53.91 0.88359 70 80 63.25 55.89 0.87724 73 30 65.96 57.86 )?965 68 35 60.65 53.95 0.88347 70 85 63.31 55.93 0.87711 73 35 66.02 57.90 )§952 68 40 60.70 53.99 0.88334 70 90 63.36 55.97 0.87698 73 40 66.07 57.94 0^940 68 45 60.75 54.03 0.88322 70 95 63.41 56.01 0.87685 73 45 66.13 57.98 OS028 68 50 60.80 54.07 0.88309 71 00 63.46 56.04 0.87672 73 50 66.18 58.02 ^M',i 68 55 60.86 54.11 0.&S297 71 05 63.52 56.08 0.87659 73 55 66.23 58.06 68 60 60.91 54.15 0.88284 71 10 63.57 56.12 0.87646 73 60 66. 2S 58.10 68 65 60.96 54.19 0.88272 71 16 63.63 56.16 0.87C)33 73 66 66.34 58.14 ^^i"'' 68 70 61.01 54.23 0.88259 71 20 63.68 56.20 0.87620 73 70 66.39 58.17 ^^'-7 68 75 61.07 54.27 0.88246 71 26 63.74 56.24 0.87607 73 75 66.45 58.21 68 80 61.12 54.31 0.88233 71 30 63.79 56.28 0.87594 73 80 66.50 58.25 68 85 61.17 54.35 0.88221 71 36 63.84 56.32 0.87581 73 85 66.56 58.29 68 90 61.22 54.39 0.88208 71 40 63.89 56.36 0.87568 73 90 66.61 58.33 68 95 61.28 54.43 0.88196 7145 63.95 56.40 0.87555 73.95 66.67 58.37 69 00 61.33 54.47 0.88183 71 60 64.00 56.44 0.87542 74 00 66.72 58.41 69 05 61.39 54.51 0.88171 71 66 64.06 56.48 0.87529 74.05 6'i rs 58.45 69 10 61.44 54.54 0.88158 71 60 64.11 56.52 0.87516 74 10 66.83 58.49 »' >7ni» 69 15 61.49 54.58 0.88145 71 65 64. 17 56.56 0.87504 74.15 66.89 58.53 018756 69 20 61.54 54.62 0.88132 71.70 64.22 56.60 0.87491 74 20 66.94 58.57 204 METHODS OF ANALYSIS [Chap. Table 16.— Alcohol Table.— Continued. SPECIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL GRAVITY 20° C. Per cent Per Grams 20° C. Per cent Per Grams 20° C^ Per cent Per C 4° by volume cent by per 4° by volume cent by per 4° by volume cent by at 20° C. weight 100 cc. at20°C. weight 100 cc. at 20° C. weight I 0.87478 74,25 67.00 58.61 0.86818 76.75 69.78 60.58 0.86137 79.25 72.63 6 0.87465 74 30 67.05 58.65 0,86805 76 80 69.84 60,62 0.86124 79 30 72.68 6 0.87452 74 35 67.11 58.69 0.86791 76 85 69.90 60,66 0,86110 79 35 72.74 6 0.87439 74.40 67.16 58.73 0.86778 76 90 69.95 60,70 0.86096 79.40 72.80 6 0.87426 74.45 67.22 58.77 0.86764 76.95 70.01 60.74 0.86082 79.45 72.86 6 0.87413 74 50 67.27 58.81 0.86751 77 00 70.06 60.78 0.86069 79 50 72.91 6 0.87400 74.55 67.33 58.85 0,86737 77 05 70.12 60.82 0.86055 79 55 72.97 € 0.87387 74 60 67.38 58.89 0,86724 77.10 70.18 60.86 0.86041 79 60 7.3.03 t 0.87373 74.65 67. U 58.93 0.86710 77.15 70.24 60.90 0.86027 79.65 73.09 i 0.87360 74.70 67.49 58.97 0.86697 77.20 70.29 60.94 0.86013 79.70 73.14 f 0.87347 74.75 67.55 59.01 0.86684 77,25 70.35 60.98 0.85999 79 75 73.20 ( 0.87334 74.80 67.61 59.04 0.86671 77,30 70.40 61.02 0,85984 79 80 73.26 i 0.87321 74.85 67.67 59.08 0,86657 77.35 70.46 61.06 0.85970 79 85 73.32 ( 0.87308 74.90 67.72 59.12 0.86644 77.40 70.51 61.10 0.85956 79.90 73.37 { 0.87295 74.95 67.78 59.16 0.86630 77.45 70.57 61.14 0.85942 79.95 73.43 ( 0.87282 75 00 67.83 59.20 0,86617 77.50 70.63 61.18 0.85928 80 00 73.49 ( 0.87269 75 05 67.89 59.24 0,86603 77.55 70.69 61.22 0.85914 80 05 73.55 0.87256 75 10 67.94 59.28 0.86589 77.60 70.74 61.25 0.85901 80.10 73.60 ,0.87243 75.15 68.00 59.32 0.86575 77,65 70.80 61.29- 0.85887 80.15 73.66 0.87230 75 20 68.05 59.36 0.86562 77.70 70.85 61.33 0.85873 80.20 73.72 0.87217 75 25 68.11 59.40 0.86548 77.75 70.91 61.37 0.85859 80.25 73.78 0.87204 75 30 68.16 59.44 0.86535 77.80 70.97 61.41 0.85846 80 30 73.83 0.87190 75 35 68.22 59,48 0.86521 77 85 71.03 61.45 0.85832 80 35 73.89 0.87177 75.40 68.27 59.52 0,86508 77.90 71.08 61.49 0.85818 80 40 73.95 0.87164 75.45 68.33 59.56 0.86494 77,95 71.14 61.53 0.85804 80.45 74.01 0.87151 75.50 68.38 59.60 0.86480 78 00 71.19 61.57 0.85789 80 50 7 4. 06 0.87138 75 55 68.44 59.64 0.86466 78 05 71.25 61.61 0.85775 80.55 74.12 0.87125 75.60 68.49 59.67 0.86453 78 10 71.31 61.65 0.85761 80 60 74. 18 0.87111 75 65 68.55 59.71 0.86439 78.15 71.37 61.69 0.85747 80 65 74.24 0.87098 75 70 68.60 59.75 0.86426 78 20 71.42 61.73 0.85733 80.70 74.30 0.87084 75.75 68.66 59.79 0.86412 78.25 71.48 61.77 0.85719 80.75 74.36 0.87071 75.80 68.72 59.83 0.86399 78 30 71.54 61.81 0.85705 80 80 74.42 0.87058 75.85 68.78 59.87 0.86385 78 35 71.60 61.85 0.85691 80 85 74.48 0.87045 75.90 68.83 59,91 0.86371 78 40 71.65 61.88 0.85677 80 90 74.53 0.87032 75.95 68.89 59.95 0.86357 78.45 71.71 61.92 0.85663 80 95 74.59 0.87019 76.00 68.94 59.99 0.86344 78.50 71.76 61.96 0.85648 81 00 74.65 0.87005 76 05 69.00 60.03 0.86330 78 55 71.82 62.00 0.85634 81.05 74.71 0.86992 76 10 69.05 60.07 0.86316 78 60 71.88 62,04 0.85620 81.10 74.77 0.86979 76.15 69.11 60.11 0.86302 78.65 71.94 62.08 0.85606 81.15 74.83 0.86966 76 20 69.16 60.15 0.86289 78.70 71.99 62.12 0.85592 81.20 74.88 0.86952 76.25 69. 2i 60.19 0.86275 78.75 72.05 62.16 0.85578 81.25 74.94 0.86939 76 30 69.27 60.23 0,86261 78 80 72.11 62.20 0.85564 81.30 75.00 0.86925 76 35 69.35 60.27 0.86247 78 85 72.17 62.24 0.85550 81 35 75.06 0.86912 76.40 69. 3S 60.31 0,86234 78 90 72.22 62.28 0.85536 81.40 75.12 0.86898 76.46 69.4& 60.35 0,86220 78.95 72.28 62.32 0.85522 81.45 75.18 0.86885 76 50 69.56 60.39 0,86206 79 00 72.34 62.36 0.85507 81 50 75.24 0.86872 76 55 69.56 60.43 0,86192 79.05 72.40 62.40 0.85493 81.55 75.30 0.86859 76 60 69.61 60.47 0.80179 79.10 72.45 62.44 0.85478 81 60 75.35 0.86845 76.65 69.67 60.51 0.86165 79.15 72.51 62.48 0.85464 81 65 75.41 0,86832 76 70 69.72 60.54 0.86151 79.20 72.57 62.52 0.85450 81.70 75.47 XVI] WINES Table 16.— Alcohol Table.— Continued. 205 t BCIFIC ALCOHOL SPECIFIC ALCOHOL SPECIFIC A.LCOHOL AVITY )°C. Per cent Per Grams °^o^c^ Per cent Per Grams 20° C. Per cent Per Grama 1° by volume cent by per 4° by volume cent by per 4° by volume|cent by per at 20°C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 cc. Cv>13G 81 75 75. 5S 64.53 0.84713 84 26 78.50 66.50 0.83957 86 76 81.56 68.48 055422 81 80 75.59 64.57 0.84698 84 30 78.56 66.54 0.83942 86 80 81.62 68.52 C5540S 81 85 75.65 64.61 0.84683 84 36 78.62 66.58 0.83927 86 85 81.68 68.56 (■;,-•!' i:{ 81 90 75.71 64.65 0.84668 84.40 78.68 66.62 0.83912 86 90 81.75 68.60 - -'1 81 95 75.77 64.69 0.84654 84.46 78.74 66.66 0.83896 86 96 81.81 68.64 v,.,i,l 82 00 75.82 64.73 0.84639 84 60 78.80 66.70 0.83881 87 00 81.87 68.68 1 ^'.:;:,o 82 05 75.88 64.77 0.84624 84.66 78.86 66.74 0.83865 87 05 81.93 68.72 1 sXy.'A't 82 10 75.94 64.81 0.84609 84.60 78.93 66.78 0.83850 87.10 81.99 68.76 ( vr):;_'2 82 15 76.00 64.85 0.84594 84.66 78.99 66.82 0.83834 87.15 82.05 68.80 1 vVinr 82 20 76.06 64.88 0.84579 84.70 79.05 66.86 0.83818 87.20 82.12 68.84 ( vV_".>:; 82 25 76.12 64.92 0.84564 84.76 79.11 66.90 0.83802 87.25 82.18 68.88 ( vi_'7!t 82 30 76.18 &4.96 0.84549 84 80 79.17 66.94 0.83787 87 30 82.24 68.91 1 ^.' Jli.") 82 35 76.24 65.00 0.84534 84.85 79.23 66.98 0.83771 87 36 82.30 68.95 -- M) 82 40 76.30 65.04 0.84519 84 90 79.29 67.02 0.83756 87.40 82.37 68.99 .1-, 82 46 76.36 65.08 0.84504 84.95 79.35 67.06 0. 83740 87 46 82.43 69.03 ('•;.3222 82 50 76.41 65.12 0.84489 86.00 79.41 67.09 0. 83725 87 50 82.49 69.07 (^207 82 55 76.47 65.16 0.84474 86.06 79.47 67.13 0.83709 87 55 82.55 69.11 mm 82 60 76.53 65.20 0.84459 86.10 79.53 67.17 0.83694 87 60 82.62 69.15 miTs 82 65 76.59 65.24 0.84444 86 16 79.59 67.21 0.83678 87 65 82.68 69.19 B5164 82 70 76.65 65.28 0.84429 86 20 79.65 67.25 0.83663 87.70 82.74 69.23 (v-.i:iO 82 75 76.71 65.32 0.84414 85 25 79.71 67.29 0.83647 87 75 82.80 69.27 ( ^:, 1 :;.') 82 80 76.77 65.36 0.84399 85.30 79.78 67.33 0.83632 87 80 82.87 69.30 (<,5121 82 85 76.83 65.40 0.84384 85 36 79.84 67.37 0.83616 87 85 82.93 69.34 OS5106 82 90 76.89 65.44 0.84369 86 40 79.90 67.41 0.83601 87 90 82.99 69.38 (S5092 82.95 76.95 65.48 0.84354 86.45 79.96 67.45 0.83585 87 95 83.05 69.42 1 >;rii )77 83 00 77.01 65.51 0.84339 85 60 80.02 67.49 0.83569 88 00 83.12 69.46 (-;.")i)(;;5 83 05 77.07 65.55 0.84323 85 55 80.08 67.53 0.83553 88 06 85.18 69.50 (85049 83 10 77.13 65.59 0.84308 85 60 80.14 67.57 0.83537 88 10 83.25 69.54 (?5n:]5 83 15 77.19 65.63 0.84293 85.65 80.20 67.61 0.83521 88 15 83.31 69.58 (<5()20 83.20 77.24 65.67 0.84278 86 70 80.27 67.65 0.83505 88.20 83.37 69.62 ( s:,( )i IB 83 26 77.30 65.71 0.84263 85 75 80.33 67.69 0.83489 88.26 83.43 69.66 (.S49'.a 83 30 77.36 65.75 0.84248 85 80 80.39 67.73 0.83473 88 30 83.50 69.70 (84977 83 35 77.42 65.79 0.84?,S3 86 86 80.45 67.77 0.83457 88 35 83.56 69.74 (84902 83 40 77.48 65.83 0.84218 85 90 80.51 67.80 0.83442 88 40 83.65 69.78 (S4948 83 45 77.54 65.87 0.84203 85 96 80.57 67.84 0.83426 88.45 83.69 69.82 [■^I'l:]:] 83 50 77.60 65.91 0.84188 86 00 80.63 67.88 0.83410 88 60 83.75 69.86 ■ 'IS 83 55 77.66 65.95 0.84172 86 06 80.69 67.92 0.83394 88 55 83.81 69.90 i:-; 83 60 77.72 65.99 0.84157 86 10 80.76 67.96 0.83379 88 60 SS.88 69.94 ^',t 83 65 77.78 66.03 0.84141 86.15 80.82 68.00 0.83363 88 65 83.94 69.98 ^,^:4 83 70 77.84 66.07 0.84126 86 20 80.88 68.04 0.83347 88.70 8400 70.01 slvV.> 83 75 77.90 66.11 0.84110 86 26 SO. 94 68.08 0.8^331 88 76 84.06 70.05 MM4 83 80 77.96 66.15 0.84095 86 30 81.00 68.12 0.83315 88 80 84.15 70.09 sis:;() 83 85 78.02 66.19 0.84080 86 36 81.06 68.16 0.83290 88 85 84.19 70.13 Msi:> 83 90 78.08 66.23 0.ai065 86 40 81.13 68.20 0.832S3 88 90 84.26 70.17 MMll 83 95 78.14 66.27 0.84049 86.46 81.19 68.24 0.83267 88 95 84.32 70.21 S47St') 84 00 78.2C 66.30 0.84034 86 60 81.25 68.28 0.83251 89 00 84.39 70.25 184772 84 05 78.26 66.34 0.84018 86 66 81.31 68.32 0.83235 89 05 S4.4-5 70.29 181757 84 10 78.S& 66.38 0.84003 86.60 81.37 68.36 0.83219 89 10 84-51 70.33 V--J.J 84.15 78.3S 66.42 0.83987 86 66 81.43 68.40 0.83203 89 15 84.57 70.37 '27 84.20 78.4. 66 46 0.83972 86 70 81.50 68.44 0.S31S6 89 20 84.64 70.41 206 METHODS OF ANALYSIS [Chap. 5 Table 16.— Alcohol Table.- —Continued. SPECiric ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL GRAVITY 20° C. Per cent Per Grams GRAVITY 20° C. Per cent Per Grams '20°C. Per cent Per Gran 4° by volume cent by per 4° by volume cent by per 4° by volume cent by per at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 c( 0.83170 89 25 8^.70 70.45 0,82332 91 75 87.96 72.42 0.81432 94.25 91.36 74.4 0.83154 89 30 84.77 70.49 0.82315 91 80 88.03 72.46 0.81413 94.30 91.43 74.4 0.83138 89 35 84.83 70.53 0.82298 91 85 88.09 72.50 0.81394 94 35 91.50 74.4 0.83121 89 40 84.90 70,57 0.82281 91 90 88.16 72.54 0.81375 94.40 91.57 74.5 0.83105 89.45 84.96 70.61 0,82263 91.95 88.22 72.58 0.81356 94 45 91.64 74.5 0.83089 89 50 85.03 70.65 0.82246 92.00 88.29 72.62 0.81337 94.50 91.71 74.5 0.83073 89 55 85.09 70.69 0.82229 92 05 88.36 72,66 0.81318 94.55 91.78 74.6 0.83056 89 60 85.15 70.72 0.82212 92 10 88.43 72,70 0.81299 94 60 91.85 74.6 0.83040 89 65 85.21 70.76 0.82194 92.15 88.49 72.74 0.81280 94.65 91.92 74.7 0.83024 89 70 85.28 70.80 0.82177 92.20 88.56 72,78 0.81260 94.70 91.99 74.7 0.83008 89.75 85.34 70.84 0.82159 92 25 88.63 72,82 0.81241 94.75 92.06 74.7 0.82991 89 80 85.41 70.88 0.82141 92 30 88.70 72.86 0.81222 94 80 92.13 74.8 0.82975 89.85 85.47 70.92 0.82123 92 35 88.76 72.90 0.81202 94.85 92.20 74.8 0.82958 89 90 85.54 70.96 0.82106 92.40 88.83 72.94 0.81183 94.90 92.27 74.9 0.82942 89 95 85.60 71.00 0.82088 92 45 88.89 72.98 0.81163 94.95 92.34 74.9 0.82925 90 00 85.67 71,04 0.82071 92 50 88.96 73.02 0.81144 95.00 92.41 74.9 0,82909 90 05 85.73 71.08 0,82053 92 55 89.03 73.06 0,81124 95 05 92.48 75.0 0.82892 90 10 85.80 71.12 0.82035 92 60 89.10 73.09 0,81105 95.10 92.55 75.0 0.82876 90.15 85.86 71,16 0.82017 92 65 89.16 73.13 0,81086 95.15 92.63 75.1 0.82859 90 20 85.93 71.20 0.82000 92.70 89.23 73.17 0.81067 95.20 92.70 75.1 0.82843 90 25 85.99 71.24 0.81982 92 75 89.30 73.21 0.81047 95 25 92.77 75.1 0.82826 90 30 86.06 71,28 0.81964 92 80 89.37 73.25 0.81028 95 30 92.84 75.2 0.82810 90 35 86.12 71,32 0.81946 92 85 89.43 73.29 0.81008 95.35 92.91 75.2 0.82793 90 40 86.19 71,36 0.81929 92,90 89.50 73.33 0.80988 95 40 92.98 75.3 0.82776 90 45 86.25 71.40 0.81911 92 95 89.57 73.37 0.80968 95 45 93.05 75.3 0.82759 90 50 86.32 71,44 0.81893 93 00 89.64 73.41 0.80949 95.50 93.12 75.3 0.82742 90 55 86.38 71,48 0.81875 93 05 89.71 73.45 0.80929 95 55 93.20 75.4 0.82725 90 60 86.45 71,52 0,81856 93 10 89.78 73.49 0.80909 95.60 93.27 75.4 0.82708 90 65 86.51 71,56 0,81838 93 15 89.84 73.53 0.80889 95 65 93.34 75.5 0.82691 90.70 86.58 71,59 0,81821 93 20 89.91 73.57 0.80869 95.70 93.41 75.5 0.82674 90 75 86.64 71,63 0.81803 93 25 89.98 73.61 0.80849 95.75 93.48 75.5 0.82657 90 80 86.71 71.67 0.81784 93 30 90.05 73.65 0.80829 95 80 93.55 75.6 0.82640 90 85 86.77 71.71 0.81766 93 35 90.12 73.69 0.80809 95 85 93.63 75.6 0.82624 90 90 86.84 71.75 0.81748 93 40 90.19 73.72 0.80789 95 90 93.70 75.7 0.82607 90 95 86.90 71.79 0.81730 93,45 90.25 73.76 0.80769 95.95 93.77 75.7 0.82590 91 00 86.97 71.83 0,81711 93 50 90.32 73,80 0.80749 96 00 93.84 75.7 0.82573 91.05 87.03 71.87 0,81693 93 55 90.39 73.84 0.80729 96 05 93.92 75.8 0.82556 91 10 87.10 71,91 0,81675 93 60 90.46 73,88 0.80709 96.10 93.99 75.8 0.82539 91 15 87.17 71,95 0,81657 93 65 90.53 73.92 0,80689 96.15 94.06 75.9 0.82522 91 20 87.24 71,99 0.81638. 93 70 90.60 73.96 0,80668 96.20 94.13 75.9 0.82505 91 25 87.30 72.03 0.81620 93 75 90.67 74,00 0,80648 96.25 94.21 75.9 0.82488 91 30 87.37 72,07 0.81601 93 80 90.74 74,04 0,80627 96 30 94.28 76.0 0.82470 91.35 87.43 72,11 0.81582 93,85 90.80 74.08 0.80607 96.35 94.35 76.0 0.82453 91 40 87.50 72,15 0,81563 93,90 90.87 74,12 0.80586 96.40 94.42 76.0 0.82436 91.45 87.56 72,19 0,81545 93,95 90.94 74,16 0.80566 96.45 94.50 76.1 0.82419 91 50 87.63 72,23 0.81526 94 00 91.01 74.20 0.80545 96.50 94.57 76.1 0.82401 91 55 87.69 72,27 0.81507 94,05 91.08 74.24 0.80525 96 55 94.65 76.2 0.82384 91 60 87.76 72,30 0.81488 94,10 91.15 74.28 0.80504 96 60 94.72 76.2 0.82367 91 65 87.83 72.34 0.81469 94,15 91.22 74.32 0.80483 96 65 94.79 76.2 0.82350 91 70 87.90 72.38 0.81450 94,20 91.29 74.36 0.80462 98 70 94.86 76.3 XVI] • WINES 207 Table 16.— Alcohol 1 ^ABLE.- -Concluded. HviTT ALCOHOL SPECIFIC ALCOHOL SPECIFIC ALCOHOL Per cent Per Grams 20° C. Per cent Per Grams GRAVITY 20° C. Per cent Per Grams lit" by volume cent by per 4° by volume cent by per 4° by volume cent by per 11 at 20° C. weight 100 cc. at 20° C. weight 100 cc. at 20° C. weight 100 cc. llo442 96 75 94.94 76.37 0.79900 98 00 96.82 77.36 0.79311 99 25 98.78 78.34 o;o42i 96 80 95.01 76.41 0.79878 98 05 96.90 77.40 0.79286 99 30 98.86 78.38 010400 96 85 95.09 76.45 0.79855 98 10 96.97 77.43 0.79262 99 35 98.94 78.42 '>;i),'^7l5 97 90 96.68 77.28 0.79360 99 15 98.62 78.26 ) i',L':; 97 95 96.75 77.32 0.70335 99 20 98.70 78.30 208 METHODS OF ANALYSIS [Chap. Table 17.— Alcoh| For calculating the percentages of alcohol in mixtures of ethyl alcohol a Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume 13.2 13.3 13.4 13.5 13.6 13,7 13.8 13.9 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16.0 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17.0 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 0 00 0 09 0.17 0.26 0.34 0.43 0.51 0.59 0.68 0.76 0.84 0.93 1 02 1 10 1.18 1.26 1 34 1.41 1.49 1.66 2,00 2.07 2.14 2.21 2.29 0.00 0.07 0.13 0.20 0.27 0.84- 0.40 0.47 0.54 0.60 0.67 0.74 0.81 0.87 0.94 1.00 1.06 1.12 1.18 1.24 1.30 1.35 1.41 1.47 1.53 1.69 1.65 1.70 1.76 1.82 0 10 0 19 0.27 0 36 0.44 0.53 0.60 0.69 0.78 0 85 0.94 1.03 1.12 1 19 1.29 1.36 1.43 1 50 1.57 1 65 1.72 1.80 1.87 1.94 2.01 2.09 2.16 2.24 2.31 2.38 0.01 0.01 0.08 0.15 0.21 0.28 0.35 0.42 0.48 0.55 0.62 0.68 0.75 0.82 0.89 0.95 1.02 1.08 1.13 1.19 1.25 1.31 1.37 1.43 1.49 1.54 1.60 1.66 1.72 1.78 1.84 1.89 0 05 0.14 0 23 0 31 0 39 0.48 0 57 0.66 0.73 0.82 0.91 0 99 1.08 1.17 1.24 1.32 1.40 1.47 1 65 1.62 1.70 1.77 1.85 1.92 1.99 2.06 2.14 2.21 2.29 2 36 2,44 2 61 2.69 0.04 0.11 0.18 0.24 0.31 0.38 0.45 0.51 0.58 0.65 0.72 0.79 0.86 0.93 0.99 1.05 1.11 1.17 1.23 1.29 1.35 1.41 1.47 1.53 1.58 1.64 1.70 1.76 1.88 1.94 2.00 2.06 0 08 0.16 0.26 0.34 0.43 0.62 0 60 0 69 0.77 0.86 0.94 1.03 1.12 1.21 1.28 1.36 1.44 1.61 1.69 1.66 1.74 1.81 1.89 1 96 2.04 2.11 2.19 2.26 2 34 2.41 2.49 2.66 2.62 2.70 2.77 • Calculated and arranged by B. H. St. John from the data of Boroshevskii and Dvorzhanchik.^ XVI] Table. water from their Zei^s immersion refractometer readings* at 17.5°-25°C. 209 6 2rc. 22° c. 23 c. 24 C. 25° c. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READINQ by by by by by by by by by weight volume weight volume weight volume weight volume weight 0.00 0.00 13.2 0 09 0.07 13.3 0.18 0.14 13.4 0 05 0.04 0.26 0.21 13.5 0.14 0.11 0 36 0.28 13.6 0 01 0.01 0 23 0.18 0 44 0.35 13.7 0 10 0.08 0 31 0.25 0.63 0.42 13.8 0 19 0.15 0 40 0.32 0.62 0.49 13.9 0 08 0.06 0.28 0.22 0 49 0.39 0.70 0.56 14.0 0 16 0.13 0 36 0.29 0 58 0.46 0.79 0.63 14.1 o'.os 0 24 0.19 045 0.36 0 67 0.53 0 88 0.70 14.2 0.10 0 33 0.26 0 54 0.43 0.75 0.60 0.97 0.77 14.3 0.17 0.41 0.33 0 63 0.50 0.84 0.67 1.06 0.85 14.4 0.23 0 50 0.40 0.72 0.57 0 93 0.74 1.15 0.92 14.5 O.SO 0.59 0.47 0.80 0.64 1.02 0.81 1 24 0.99 14.6 0.37 0 68 0.64 0.89 0.71 1.11 0.88 1 32 1.05 14.7 0.44 0 77 0.61 0.98 0.78 1 19 0.95 1.40 1.11 14.8 0.51 0 86 0.68 1.07 0.85 1.28 1.02 1.47 1.17 14.9 0.58 0.94 0.75 1.16 0.92 1.36 1.08 1.66 1.23 15.0 0.65 1 03 0.82 1.24 0.99 1.44 1.14 1.63 1.29 15.1 0.72 1 12 0.89 1.32 1.05 1.61 1.20 1.71 1.36 15.2 0.79 1.21 0.96 1.40 1.11 1.59 1.26 1.79 1.42 15.3 0.85 1.29 1.02 1.47 1.17 1.66 1.32 1.86 1.48 15.4 0.92 1 36 1.08 1.55 1.23 1.74 1.S8 1.94 1.54 15.5 0.99 1.44 1.15 1 62 1.29 1.82 1-44 2.01 1.60 15.6 1.05 1.52 1.21 1.70 1.35 1.90 1.51 2.09 1.66 15.7 1.11 1.60 1.27 1.77 1.41 1.97 1.67 2.17 1.72 15.8 1.17 1.67 l.SS 1.86 1.47 2.06 1.63 2.26 1.79 15.9 1.23 1.75 1.39 1.92 1.53 2 12 1.69 2 33 1.85 16.0 1.29 1.82 1.45 2.00 1.59 2.20 1.75 2.40 1.91 16.1 1.35 1 90 1.51 2.08 1.65 2.27 1.81 2.48 1.97 16.2 1.41 1.97 1.57 2.16 1.72 2.36 1.87 2 66 2.05 16.3 1.47 2 05 1.63 2.24 1.78 2.43 1.93 2.62 2.09 16.4 1.53 2.12 1.69 2.31 1.84 2 50 1.99 2.70 2.15 16.5 1.59 2.20 1.75 2 39 1.90 2 57 2.05 2.77 2.21 16.6 1.65 2.27 1.81 2.46 1.96 2 65 2.11 2 86 2.27 16.7 1.71 2 36 1.87 2.53 2.02 2 72 2.17 2 92 2.33 16.8 1.77 2.43 1.93 2.61 2.08 2.80 2.23 2.99 2.38 16.9 1.83 2.60 1.99 2.69 2.14 2.87 2.29 3 06 2.44 17.0 1.89 2.67 2.05 2 76 2.20 2.96 2.36 3.14 2.60 17.1 1.95 2 65 2.11 2 82 2.25 3 02 2.41 3 21 2.66 17.2 2.01 2.72 2.17 2.90 2.31 3.10 2.47 3.29 2.62 17.3 2.07 2.79 2.23 2.97 2.37 3.17 2.63 3.36 2.68 17.4 2.12 2.86 2.28 3.04 2.43 3 26 2.59 3.43 2.74 17.5 2.18 2 94 2.34 3 12 2.49 3 32 2.65 3 61 2.80 17.6 2.24 3.01 2.40 3 20 2.55 3 39 2.70 3 68 2.86 17.7 2.30 3.09 2.46 3.27 2.61 3 46 2.76 3 66 2.92 17.8 2.36 3.16 2.52 3.35 2.67 3 53 2.82 3.73 2.98 17.9 210 METHODS OF ANALYSIS [Chap. 6 Table 17.- -Alcoho 17.5 °c. 18° C. 19° c. 20° c. 21° C. SCALE BEADING Per cent Per cont Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 18.0 2.36 1.88 2 45 1.95 2.66 2.12 2.85 2.27 3.04 18.1 2 43 l.H 2 52 2.01 2.74 2.18 2 92 2.33 3.11 18.2 2.50 2.00 2.60 2.07 2.81 2.24 3.00 2.39 3 19 18.3 2.57 2.05 2.67 2.13 2.89 2.30 3.07 2.45 3 26 18.4 2.65 2.11 2.75 2.19 2.96 2.36 3.15 2.51 3.34 18.5 2.72 2.17 2 82 2.25 3 03 2.41 3 22 2.57 3.41 18.6 2 80 2.23 2.90 2.31 3.10 2.47 3 30 2.63 3 48 18.7 2.87 2.29 2 97 2.37 3.17 2.53 3 37 2.69 3 55 18.8 2 95 2.35 3 05 2.43 3 25 2.59 3 45 2.75 363 18.9 3.02 2.41 3.12 2.49 3 32 2.65 3 52 2.81 3 70 19.0 3 10 2.47 3 19 2.54 3 40 2.71 3 59 2.86 377 19.1 3 17 2.53 3 26 2.60 3.47 2.77 3 66 2.92 3 85 19.2 3 25 2.59 3.34 2.66 3 55 2.83 3 73 2.98 3 92 19.3 3 32 2.65 3.41 2.72 3 62 2.89 3 81 3.04 4 00 19.4 3 39 2.70 3 48 2.78 3 70 2.95 3.88 3.10 4.07 19.5 3 46 2.76 3 56 2.84 3 77 3.01 3 96 3.16 4.14 19.6 3 53 2.82 3 63 2.90 3,84 3.06 4 03 3.22 4 22 19.7 3 61 2.88 3.71 2.96 3.91 3.12 4.10 3.27 4.29 19.8 3 68 2.94 3 78 3.02 3.98 3.18 4.17 3.33 4 37 19.9 3 76 3.00 3 86 3.08 4.06 3.24 4.25 3.39 4.44 20.0 3 83 3.08 3 93 3.13 4.13 3.30 4 32 3.45 4.52 20.1 3.90 3.12 4 00 3.19 4.20 3.35 4 39 3.51 4 59 20.2 3 97 3.17 4 07 3.25 4.27 3.41 4.47 3.57 4 66 20.3 4.04 3.23 4 14 3.31 4.34 3.47 4 54 3.63 4.74 20.4 4.12 3.29 4 22 3.37 4.42 3.53 4.61 3.68 4 82 20.5 4.19 3.35 4.29 3.43 4.49 3.59 4.68 S.74 4.89 20.6 4.26 3.41 4 36 3.49 4.56 3.65 4.75 3.80 4 96 20.7 4 33 3.46 4.43 3.54 4.63 3.70 4 83 3.86 6 03 20.8 4.41 3.52 4 51 3.60 4 70 3.76 4 90 3.92 5 10 20.9 4.48 3.58 4.58 3.66 4.78 3.82 4.97 3.98 5.17 21.0 4.56 3.64 4 65 3.72 4 85 3.88 5.04 4.03 5.24 21.1 4 63 3.70 4.73 3.78 4.92 3.94 5.11 4.09 5 31 21.2 4 70 3.76 4 80 3.84 4.99 3.99 5 19 4.15 5 39 21.3 4.77 3.81 4 87 3.89 5 06 4.05 5 26 4.21 5.46 21.4 4.84 3.87 4.94 3.95 5.14 4.11 5 33 4.26 5.53 21.5 4.92 3.93 5 01 4.01 5 21 4.17 5.40 4.32 5 60 21.6 4 99 3.99 5 09 4.07 5 28 4.22 5.47 4.38 5.67 21.7 5 06 4.05 5.16 4.13 5 35 4.28 5.54 4.U 5.75 21.8 5 13 4.10 5 23 4.18 5 43 4.34 5.61 4.49 5 82 21.9 5.20 4.16 5 30 4-24 5.50 4-40 5 69 4.55 5.89 22.0 5.27 4.22 5 37 4.30 5.57 4-45 5 76 4.61 5.96 P 22.1 5.34 4.27 5.44 4.35 5.64 4.51 5.83 4.67 6 03 22.2 6.41 4.33 5 51 4-41 5.71 4.57 5.90 4.72 6.11 22.3 5.49 4.39 5.58 4-47 5.78 4.63 5.97 4.78 6.18 22.4 5.56 445 5.65 4.53 5.85 4.68 6.05 h-84 6.25 22.5 5.63 4.51 5.72 4.58 5.92 4.74 6.12 4.90 6 32 22.6 5.70 4.56 5.80 4-64 6.00 4.80 6.19 4.95 6 39 22.7 5.77 4.62 5.87 4.70 6.07 4.86 6 26 5.01 6 46 22.8 5.85 4.68 5.94 4.75 6.14 4.91 6.33 5.07 6 53 22.9 5 92 474 6 01 4.81 6.21 4.97 6.40 5.13 6 60 XVI] WINES 211 Fable.- -Continued. ( 21° C. 22° C. 23° C. 24° C. 25° c. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weight volume weight volume weight volume weight volume weight 2.42 3.23 2.58 3 42 2.73 3 61 2.88 3 81 S.O4 18.0 248 3 30 2.63 3 50 2.79 3.68 2.94 3 88 3.10 18.1 2.54 3.37 2.69 3 57 2.85 3 76 3.00 3 96 3.16 18.2 2.60 3.45 2.75 3.64 2.91 3 83 3.06 4 03 3.22 18.3 2.66 3.52 2.81 3 71 2.96 3 91 3.12 4.11 3.28 18.4 2.72 3.59 2.87 3.78 3.02 3 98 3.18 4.18 3.34 18.5 2.78 3.66 2.92 3.86 3.08 4.06 3.24 4.26 3. 40 18.6 2.83 3.73 2.98 3 93 3.14 4.13 3.30 4 33 3.46 18.7 2.89 3.81 3.04 4.01 3.20 4.21 3.36 4 41 3.52 18.8 2.95 3.88 3.10 4.08 3.26 4 28 3.42 4.48 3.58 18.9 3.01 3.96 3.16 4.16 3.32 4.36 3.48 4.56 3.64 19.0 3.07 4.03 3.22 4 23 3.38 4.43 3.54 4.63 3.70 19.1 3. IS 4.11 3.28 4 31 3.44 4.51 3.60 4.70 3.76 19.2 3.19 4.18 3.34 4.38 3.60 4.58 3.66 4.78 3.82 19.3 3.25 4.26 S.40 4.46 3.66 4.65 3.72 4.85 3.88 19.4 3. 31 4.33 3.46 4.53 3.62 4.73 3.78 4.93 3.94 19.5 3.37 4.41 3.52 4.61 3.68 4.80 3.84 5.00 4.00 19.6 3.43 4.48 3.58 4.68 3.74 4.88 3.90 5 08 4.06 19.7 3.49 4.56 3.64 4.75 3.80 4 95 3.96 5.15 4.12 19.8 3.65 4.63 3.70 4.83 3.86 6 03 4.02 5.22 4.17 19.9 3.61 4.72 3.77 4.90 3.92 5.10 4.08 5.29 4.23 20.0 3.67 4.79 3. 83 4.98 3.98 5.17 4.13 6.36 4.29 20.1 3.73 4.87 3.89 5 05 4.04 5 24 4.19 5.44 4.36 20.2 3.79 4.94 3.95 5 13 4.10 531 4.25 5 51 4-41 20.3 3.85 5.01 401 5 20 4.16 5 38 4.31 5.58 4.47 20.4 3.91 5.08 4-06 5 27 4.21 5 45 4.37 5 65 4.62 20.5 3.97 5.15 4-12 5 34 4.27 5.52 4.42 5 72 4.68 20.6 4.02 5.22 4-18 5.41 4.33 5.60 4-48 5.80 4.64 20.7 4.O8 5.29 .^.^4 5.48 4.39 5.67 4.64 5.87 4.70 20.8 4.14 5.36 4.^9 5.55 4-45 5.75 4. 60 5.95 4.76 20.9 4.20 5.44 4.35 5.62 4.50 5.82 4.66 6.02 4.81 21.0 4.25 5.51 4.4^ 5.70 4.56 5.89 4.72 6.09 4.87 21.1 4.31 5.58 4-47 5.77 4.62 5 96 4.77 6.16 4.93 21.2 4.37 5.65 4.5^ 5.84 4.68 6.03 4.83 6 23 4.99 21.3 4.43 5.72 4.5S 5.91 4.73 6.11 4.89 6.30 5.06 21.4 4-48 5.80 4.64 5.98 4.79 6.18 4.95 6.37 5.10 21.5 4.54 5.87 4.70 6.06 4.85 6 25 5.01 6.44 5.16 21.6 4.60 5.94 4.75 6.13 4.91 6 32 5.06 6.52 6.22 21.7 4.66 6.01 4.8^ 6.20 4.97 6.39 5.12 6.59 6.28 21.8 4.71 6.08 4.S7 6 27 5.02 6.47 5.18 6.66 5.34 21.9 4.77 6.15 4.93 6 34 5.0s 6.54 5.24 6.73 5.39 22.0 4.83 6.22 4.5S 6.42 5.14 6.61 6.29 6.80 5.46 22.1 4.89 6.29 5.04 6.49 5.20 6.68 6.35 6 87 6.61 22 2 4.95 6.36 5.70 6.56 5.25 6.75 6.41 6.94 5.67 22^3 5.00 6.43 5.;5 6.63 5. 31 6.82 5.47 7.01 5.62 22.4 5.06 6.50 5.21 6.70 5.37 6.89 5.52 7.08 6.68 22.5 6.11 6.57 5.57 6.77 5.43 6.96 6.68 7.16 5.74 22.6 5.17 6.64 5.33 6.84 5.48 7.03 5.64 7.23 6.80 22.7 6.28 6.71 5.38 6 91 5.54 7.10 5.70 7.31 5.86 22.8 6.29 6.78 5.44 6.99 5.60 7.17 5.75 7.38 5.91 1 22.9 212 6 METHODS OF ANALYSIS [Chap. Table 17.— Alcoho 17.5 ' c. 18° C. 19° C. 20° C 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 23.0 5 99 4.75 6.08 4.87 6 28 5.03 6.47 5.18 6.67 23.1 6 06 A.85 6.15 4.93 6 35 5.09 6 54 5.24 6.74 23.2 6 13 4.91 6.22 4.98 6 42 5.14 6 61 5.30 6.81 23.3 6.20 4.97 6 29 5.04 6.49 5.20 6.68 5.36 6.88 23.4 6.27 5.02 6 36 5.10 6 56 5.26 6.75 5.41 6.95 23.5 6 34 5.08 6 43 5.15 6 63 5.31 6.83 5 47 7.02 23.6 6 41 5.14 6 50 5.21 6 70 5.37 690 5.53 7.09 23.7 6 48 5.19 6 57 5.27 6 78 5.43 6 97 5.59 7 16 23.8 6 55 5.25 6 64 5.32 6.85 5.49 7 04 5.64 7.23 23.9 6.62 5.30 6.71 5.38 6.92 5.54 7 11 5.70 7 31 24.0 6 69 5.36 6 78 5.44 6.99 5.60 7 18 5.76 7.38 24.1 6 76 5.42 6 85 5.49 7 06 5.66 7.26 5.82 7.45 24.2 6 83 5.47 6 92 5.55 7.13 5.71 7 32 5.87 7.62 24.3 6 90 5.53 6 99 5.61 7 20 5.77 7 39 5.93 7.59 24.4 6 97 5.59 7.06 5.66 7.27 5.83 7.46 5.99 7 66 24.5 7.04 5.64 7.13 5.72 7.34 5.89 7 53 6.04 7.73 24.6 7 11 5.70 7 20 5.78 7.41 5.94 7.60 6.10 7 80 24.7 7.18 5.76 7.27 5.83 7.48 6.00 7.67 6.15 7 86 24.8 7.25 5.81 7.35 5.89 7 55 6.06 7.74 6.21 7 93 24.9 7 32 5.87 7.42 5.95 7 62 6.11 7.81 6.26 800 25.0 7.39 5.93 7 49 6.01 7.68 6.16 7 88 6.32 8.06 25.1 7 46 5.98 7.56 6.06 7.75 6.22 7.94 6.37 8.13 25.2 7 53 6.04 7 63 6.12 7 82 6.27 8 01 6.43 8 20 25.3 7 59 6.09 7 69 6.17 7 89 6.33 8 07 6.48 8.27 25.4 7.66 6.15 7.76 6.23 7 95 6.38 8 14 6.54 8.34 25.5 7.73 6.20 7 83 6.28 8 02 6.44 8.21 6.59 8.41 25.6 7 80 6.26 7 90 6.34 8 09 6.49 8 28 6.65 8.48 25.7 7 87 6.31 7 96 6.39 8 16 6.55 8 35 6.70 8 55 25.8 7.94 6.37 8 03 6.44 8 22 6.60 8.42 6.76 8.62 25.9 8 00 6.42 8 10 6.50 8.29 6.66 8 48 6.81 8.69 26.0 8 07 6.48 8.16 6.55 8 36 6.71 8 55 6.87 8.75 26.1 8.14 6.53 8 23 6.61 8.43 6.77 8 62 6.92 8 82 26.2 8 21 6.59 8 30 6.66 8 50 6.82 8 69 6.98 8 89 1 26.3 8 27 6.64 8 37 6.72 8.57 6.88 875 7.03 8.96 26.4 8.34 6.70 8 44 6.78 8 63 6.93 8 82 7.09 9.03 26.5 8.41 6.75 8.50 6.83 8 70 6.99 8.89 7.15 9 10 26.6 8.48 6.81 8 57 6.88 8 77 7.04 8 96 7.20 9.16 26.7 8.55 6.86 8 64 6.94 8.84 7.10 9 03 7.26 9 23 26.8 8.62 6.92 8.71 6.99 8 91 7.15 9.10 7.31 9.30 26.9 8.68 6.97 8.78 7.05 8 98 7.21 9.17 7.37 9.37 27.0 8.75 7.03 8.85 7.11 9 05 7.27 9.23 7.42 9.44 27.1 8.82 7.08 8 91 7.16 9.11 7.32 9 30 7.48 9.51 27.2 8 89 7.14 8.98 7.22 9 18 7.38 9.37 7.54 . 9 58 27.3 8 95 7.19 9 05 7.27 9 25 7.43 9.44 7.59 9 65 27.4 9 02 7.25 9 12 7.33 9.32 7.49 9.51 7.65 9.71 27.5 9 09 7.30 9 19 7.38 9.38 7.54 9 58 7.70 9.78 27.6 9 16 7.36 9 26 7.44 9 45 7.60 9 65 7.76 9 85 27.7 9 22 7.41 9 32 7.49 9.52 7.65 9 72 7.82 9.91 27.8 9 29 7.47 9 39 7.55 9.59 7.71 9.79 7.87 9.98 27 9 9 36 7.52 9 46 7.60 9.65 7.76 9.86 7.93 10.05 XVI] Table.— Continued. 213 6 21° C. 22° c. 23° c. 24° c. 25° C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weight volume weight volume weight volume weight volume weight 5.SA 6.86 5.50 7.06 5.66 7.24 5.81 7.45 5.97 23.0 5.10 6 93 5.66 7.13 5.71 7.32 5.87 7.52 6.03 23 1 B.46 7.00 5.61 7 20 5.77 7 39 5.93 7.59 6.08 23.2 5.51 7.07 5.67 7 27 5.83 7.46 5.98 7 66 6.14 23.3 5.57 7.14 5.73 7.34 5.89 7.53 6.04 7.73 6.20 23.4 5.es 7 21 5.78 7.41 5.94 7.60 6.10 7.80 6.25 23.5 5.69 7.28 5.84 7.48 6.00 7 67 6.15 7.87 6.31 23.6 5.7h 7.35 5.89 7.55 6.06 7.74 6.21 7.94 6.37 23.7 5.80 7.42 5.95 7 62 6.11 7 81 6.27 8.00 6.42 23 8 5.86 7 49 6.01 7.69 6.17 7.88 6.32 8.07 6.48 23.9 5.92 7.56 6.07 7 76 6.22 7 96 6.38 8 14 6.53 24.0 5.97 7 63 6.12 7 83 6.28 8 02 6.44 8.21 6.59 24.1 6 0^ 7.70 6.18 7.90 6.34 8 09 6.49 8.28 6.65 24.2 6.08 7.77 6.24 7.97 6.39 8 16 6.55 8.35 6.70 24.3 6.U 7 84 6.29 8.04 6.45 8 23 6.60 8.42 6.76 24.4 6.20 7 91 6.35 8 10 6.50 8 30 6.66 8.48 6.81 24.5 6.25 7 98 6.41 8.17 6.56 8.37 6.72 8.56 6.87 24 6 6. SI 8.05 6.46 8.24 6.62 8.44 6.77 8.62 6.93 24.7 6.S6 8 12 6.52 8.31 6.67 8.51 6.83 8 69 6.98 24.8 6.42 8.19 6.58 8.38 6.73 8.58 6.89 8.76 7.04 24.9 6.47 8.26 6.63 8.45 6.79 8 64 6.94 8.84 7.10 25.0 6.5S 8 33 6.69 8.52 6.84 8.71 7.00 8.91 7.15 25.1 6.59 8 40 6.75 8 59 6.90 8.78 7.06 8 98 7.21 25.2 6.64 8.47 6.80 8 66 6.96 8 85 7.11 9 05 7.27 25.3 6.70 8 54 6.86 8 73 7.01 8.92 7.17 9 12 7.33 25.4 6.75 8 61 6.92 8 80 7.07 8 99 7.23 9.19 7.38 25.5 6.81 8 68 6.97 8 86 7.12 9 06 7.28 9.26 7.44 25.6 6.87 8 75 7.03 8 93 7.18 9 13 7.34 9 33 7.50 25.7 6.92 8 82 7.08 9.00 7.23 9 20 7.40 9 39 7.55 25.8 6.98 8.89 7.14 9.07 7.29 9.27 7.45 9 46 7.61 25.9 7.0S 8 95 7.19 9 14 7.35 9.34 7.51 9 53 7.67 26.0 7.09 9 02 7.25 9 21 7.40 9 41 7.56 9.60 7.73 26.1 7.14 9.09 7.30 9 28 7.46 9.48 7.62 9 67 7.78 26.2 7.20 9 16 7.36 9 35 7.51 9.55 7.68 9 74 7.84 26.3 7.25 9 22 7.41 9.42 7.57 9 61 7.73 9 81 7.90 26.4 7. SI 9 29 7.47 9.49 7.63 9.68 7.79 9 88 7.95 26.5 7.S6 9 36 7.52 9.55 7.68 9.75 7.85 9 95 8.01 26.6 7.42 9 43 7.58 9 62 7.74 9.82 7.90 10 02 8.07 26.7 7.47 9.49 7.63 9 69 7.79 9 89 7.96 10 09 8.12 26.8 7.5S 9 66 7.69 9.76 7.85 9 96 8.02 10.16 8.18 26.9 7.59 9 63 7.74 9 83 7.91 10 03 8.07 10 23 8.24 27.0 7.65 9.70 7.80 9.90 7.96 10.10 8.13 10 30 8.29 27.1 7.70 9 76 7.85 9.97 8.02 10.17 8.18 10 37 8.35 27.2 7.76 9 83 7.91 10.03 8.07 10.24 8.24 10.44 8.40 27.3 7.81 9 90 7.96 10.10 8.13 10.31 8.S0 10.51 8.46 27.4 7.86 9.97 8.02 10.17 8.18 10.38 8.S5 10.58 8.52 27.5 7.92 10.03 8.07 10.24 8.24 10.45 8.41 10.65 8.57 27.6 7.97 10.10 8.13 10.31 8.30 10.51 8.46 10.72 8.6S 27.7 8. OS 10.17 8.18 10 38 8. 85 10.58 8.52 10.79 8.69 27.8 8.08 10.24 8.24 10.45 8.41 10.65 8.58 10.86 8.74 27.9 214 METHODS OF ANALYSIS [Chap. 6 Table 17.- -Alcohc 17.5 °C. 18 C. 19° C. 20 C. 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 28.0 9.43 7.58 9.53 7.66 9.72 7.82 9 92 7.98 10 12 28.1 9 50 7.64 9 59 7.71 9 79 7.87 9.99 8.04 10 18 28.2 9 57 7.69 9 66 7.77 9 86 7.93 10 06 8.09 10 25 28.3 9 64 7.75 9 73 7.82 9 92 7.98 10 13 8.15 10 32 28.4 9.70 7.80 9 80 7.88 9 99 8.04 10 19 8.20 10 39 28.5 9 77 7.86 9 86 7.93 10.06 8.09 10 26 8.26 10 45 28.6 9 84 7.91 9 93 7.99 10.13 8.15 10 32 8.31 10.52 28.7 9 91 7.97 10 00 8.04 10 19 8.20 10 39 8.36 10.59 28.8 9 97 8.02 10 07 8.10 10.26 8.26 10 46 8.42 10.66 28.9 10.04 8.08 10 13 8.15 10 32 8.31 10 52 8.47 10.73 29.0 10.10 8.13 10 19 8.20 10.39 8.36 10 59 8.53 10 79 29.1 10.17 8.18 10 26 8.26 10 46 8.42 10 66 8.58 10 86 29.2 10.24 8.U 10 33 8.31 10 52 8.47 10 73 8.64 10 93 29.3 10.30 8.29 10 40 8.37 10 59 8.53 10 79 8 69 11.00 29.4 10.36 8.34 10 46 8.42 10.66 8.58 10.86 8.74 11.06 29.5 10 43 8.40 10 52 8.47 10.73 8.64 10 93 8.80 11 13 29.6 10 50 8.45 10 59 8.53 10.79 8.69 10 99 8.85 11 20 29.7 10 56 8.50 10 66 8.58 10.86 8.74 11.06 8.91 11.27 29.8 10 63 8.56 10 72 8.63 10 93 8.80 11.12 8.96 11 33 29.9 10 69 8.61 10 79 8.69 10.99 8.85 11.19 9.02 11.39 30.0 10.76 8.66 10 86 8.74 11.06 8.91 11 26 9.07 11.46 30.1 10 83 8.72 10 93 8.80 11.12 8.96 11 32 9.12 11.52 30.2 10 89 8.77 10 99 8.85 11.18 9.02 11 38 9.18 11 59 30.3 10 95 8.82 11 05 8.90 11 25 9.07 11 45 9.23 11.66 30.4 11 02 8.88 11 12 8.96 11 31 9.12 11 51 9.28 11.72 30.5 11 08 8.93 11 18 9.01 11 38 9.18 11.58 9.34 11 79 30.6 11 15 8.98 11 25 9.06 11.44 9.23 11 64 9.39 11 85 30.7 11 21 9.04 11 31 9.12 11 51 9.28 11 71 9.44 11 92 30.8 11 28 9.09 11 38 9.17 11.58 9.34 11 78 9.50 11 99 30.9 11 34 9.14 11 44 9.22 11 64 9.39 11 84 9.55 12 05 31.0 11 41 9.19 11 51 9.28 11 71 9.4^ 11 91 9.60 12 12 31.1 11 47 9.25 11 57 9.33 11.77 9.49 11 97 9.66 12 18 31.2 11.54 9.30 11 64 9.38 11 84 9.55 12 04 9.71 12 25 31.3 11 60 9.35 11.70 9.43 11 90 9.60 12.11 9.76 12 32 31.4 11.66 9.40 11 77 9.49 11.97 9.65 12 17 9.82 12.38 31.5 11 73 9.46 11 83 9.54 12 03 9.71 12.24 9.87 12 45 31.6 11.79 9.51 11 90 9.59 12 10 9.76 12 30 9.92 12 51 31.7 11 86 9.56 11.96 9.65 12.16 9.81 12 37 9.98 12.58 31.8 11.92 9.62 12.03 9.70 12 23 9.87 12.43 10.03 12 64 31.9 11.99 9.67 12.09 9.75 12.29 9.92 12 50 10.09 12.71 32.0 12 05 9.72 12.15 9. SO 12.36 9.97 12.57 10.14 12.78 32.1 12.12 9.77 12.21 9.86 12.42 10.0.; 12 63 10.19 12.84 32.2 12.18 9.83 12 28 9.91 12.49 10.08 12.70 10.25 12.91 32.3 12.24 9.88 12 34 9.96 12.55 10.13 12 76 10.30 12 97 32.4 12.31 9.93 12.40 10.02 12.62 10.19 12.83 10.35 13.04 32.5 12 37 9.98 12 47 10.07 12.68 10.24 12.89 10.41 13.10 32.6 12.43 10.04 12.54 10.12 12.75 10.29 12.96 10.46 13.17 32.7 12.50 10.09 12 60 10.17 12.81 10.34 13 03 10.52 13.24 32.8 12.56 10.14 12.67 10.23 12.88 10.40 .13.09 10.57 13.30 32.9 12 62 10.19 12.73 10.28 12. S4 10.45 13.15 10.62 13 37 XVI] 215 Table. — Continued. 21° C. 22 C. 23° c. 24° C. 25° C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weight volume weight volume weight volume weight volume weight 8.H 10 31 8.30 10 51 8.46 10 72 8.63 10 93 8.80 28.0 8.19 10 38 8.35 10 58 8.52 10 79 8.69 10 99 8.86 28.1 8.25 10 45 8.41 10 65 8.58 10 86 8.74 11.06 8.91 28.2 8.S0 10 52 8.46 10.72 8.63 10 93 8.80 1113 8.97 2S.3 8.S6 10 59 8.52 10 79 8.69 11 00 8.86 11.20 9.02 28.4 8.41 10 66 8.58 10 86 8.74 11 06 8.91 1127 9.08 28.5 8.47 10 72 8.63 10 93 8.80 11 13 8.97 1133 9.13 28.6 8.52 10 79 8.69 11 00 8.86 11.20 9.02 11.40 9.19 28.7 8.58 10.86 8.74 11.06 8.91 11.27 9.08 11.47 9.24 28.8 8.64 10 93 8.80 11.13 8.97 11 33 9.13 1154 9.30 28.9 8.69 11 00 8.86 11 20 9.02 11 40 9.19 11.61 9.36 29.0 8.75 11 06 8.91 11 27 9.08 11 47 9.24 1168 9.41 29.1 8.80 11.13 8.97 11.33 9.13 11 54 9.30 11.75 9.47 29.2 8.86 11 20 9.02 11.40 9.19 11.60 9.35 11.81 9.62 29.3 8.91 11 27 9.08 11.47 9.24 11.67 9.41 11.88 9.58 29.4 8.97 11 33 9.13 11 54 9.30 11 74 9.46 11.94 9.63 29.5 9.02 11.39 9.18 11 60 9.35 11.81 9.52 12.01 9.69 29.6 9.08 11 46 9.24 11.67 9.41 11 87 9.67 12.08 9.75 29.7 9.13 11 53 9.29 11.74 9.46 11 94 9.63 12.15 9.80 29.8 9.18 11 60 9.35 11.81 9.52 12 01 9.69 12.22 9.86 29.9 9.24 11 66 9.40 11.87 9.67 12 08 9.74 12.29 9.91 30.0 9.29 11 73 9.46 11 93 9.63 12 14 9.80 12.36 9.97 30.1 9.S4 11 79 9.51 12 00 9.68 12 21 9.85 12 42 10.02 30.2 9.40 11 86 9.57 12 07 9.74 12 28 9.91 12 49 10.08 30.3 9.45 11 93 9.62 12 13 9.79 12 34 9.96 12.56 10.13 30.4 9.50 11 99 9.67 12 20 9. So 12 41 10.02 12.63 10.19 30.5 9.56 12 06 9.73 12 27 9.90 12 48 10.07 12.70 10.24 30.6 9.61 12 13 9.78 12 34 9.96 12 55 10.13 12.77 10.30 30.7 9.67 12 19 9.84 12 40 10.01 12 61 10.18 12 84 10.36 30.8 9.72 12 26 9.89 12 47 10.07 12 68 10.24 12,90 10.41 30.9 9.77 12 32 9.95 12 54 10.12 12.76 10.29 12.97 10.47 31.0 9.83 12 39 10.00 12 60 10.17 12 82 10.35 13.04 10.52 31.1 9.88 12 46 10.05 12 67 10.23 12 89 10.40 13.11 10.58 31.2 9.94 12 52 10.11 12 74 10.28 12 95 10.46 13.17 10.63 31.3 9.99 12 59 10.16 12 81 10.34 13 02 10.51 13.24 10.69 31.4 10.04 12 66 10.22 12 87 10.39 13 09 10.67 13.31 10.74 31.5 10.10 12 72 10.27 12 94 10.45 13 15 10.62 13 37 10.80 31.6 10.15 12 79 10.32 13 01 10.50 13 22 10.68 13.44 10.86 31.7 10.21 12 85 10.38 13 07 10.55 13.29 10.73 13.51 10.91 31.8 10.26 12 92 10.43 13.14 10.61 13.35 10.78 13.57 10.97 31.9 10.31 12 99 10.49 13 20 10.66 13 42 10.84 13.64 11.02 32.0 10.37 13 05 10.54 13 27 10.72 13.49 10.90 13.71 11.08 32.1 10.42 13 12 10.59 13 34 10.77 13 55 10.95 13.77 11.13 32.2 10.48 13 18 10.65 13 40 10.83 13.62 11.01 13.84 11.19 32.3 10.53 13 25 10.70 13.47 10.88 13.69 11.06 13.91 11.24 32.4 10.58 13 32 10.76 13 53 10.94 13.75 11.11 13 97 11.50 32.5 10.64 13 38 10.81 13.60 10.99 13 82 11.17 14.04 11. S5 32.6 10.69 13 45 10.87 13.66 11.04 13 89 11.22 14.11 11.41 32.7 10.75 13.51 10.92 13.73 11 .10 13 95 11.28 14.17 11.46 32.8 10. SO 13 58 10.97 13 80 11.15 14.02 11.33 14 24 11.52 32.9 216 6 METHODS OF ANALYSIS [Chap. Table 17— Alcohc 17.5 °C. 18 C. 19 C. 20 c. 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 33.0 12 69 10.24 12.79 10.33 13.01 10.50 13.22 10.68 13.43 33.1 12.76 10. SO 12 86 10.38 13.07 10.56 13 28 10.73 13 50 33.2 12 82 10.35 12.92 10.43 13.13 10.61 13 35 10.79 13 56 33.3 12.88 10.40 12.99 10.49 13.20 10.66 13.41 10.84 13.63 33.4 12.95 10.45 13.05 10.54 13.26 10.71 13.48 10.89 13.69 33.5 13.01 10.50 13.11 10.59 13 32 10.77 13.54 10.95 13.76 33.6 13.08 10.56 13 18 10.64. 13 39 10.82 13.61 11.00 13.82 33.7 13.14 10.61 13.24 10.70 13.45 10.87 13.67 11.05 13 89 33.8 13 20 10.66 13 30 10.75 13.52 10.93 13.74 11.10 13.95 33.9 13.26 10.71 13.37 10.80 13.58 10.98 13.80 11.16 14.02 34.0 13 33 10.77 13 43 10.85 13 64 11.03 13.86 11.21 14.08 34.1 13.39 10.82 13.49 10.91 13.71 11.08 13.93 11.26 14 15 34.2 13.45 10.87 13.56 10.96 13.77 11.13 13 99 11.31 14.21 34.3 13.52 10.92 13.62 11.01 13.83 11.19 14.06 11.36 14.27 34.4 13.58 10.97 13.68 11.06 13.90 11.24 14.12 11.41 14.34 34.5 13 64 11.03 13 75 11.11 13.96 11.29 14.18 11.47 14.40 34.6 13.70 11.08 13 81 11.16 14.02 11.34 14.25 11.52 14.47 34.7 13.77 11.13 13.87 11.22 14.08 11.39 14.31 11.57 14 53 34.8 13 83 11.18 13 94 11.27 14.14 11.44 14.37 11.62 14.59 34.9 13.89 11.23 14.00 11.32 14.20 11.49 14.43 11.67 14.66 35.0 13.96 11.28 14.06 11.37 14.27 11.55 14.50 11.73 14.72 35.1 14.02 11.33 14.13 11.42 14 33 11.60 14.56 11.78 14 78 35.2 14 08 11.38 14.19 11.47 14.39 11.65 14.62 11.83 14 85 35.3 14.14 11.44 14.25 11.52 14.46 11.70 14.69 11.88 14 91 35.4 14 21 11.49 14.31 11.57 14 52 11.75 14.75 11.93 14.97 35.5 14.27 11.54 14.38 11.63 14 59 11.81 14 81 11.99 15 04 35.6 14 33 11.59 14.44 11.68 14 65 11.86 14 87 12.04 15 10 35.7 14.39 11.64 14.50 11.73 14.71 11.91 14.94 12.09 15 16 35.8 14.46 11.69 14 56 11.78 14.78 11.96 15.00 12.14 15 23 35.9 14.52 11.74 14.63 11.83 14.84 12.01 15.06 12.19 15.29 36.0 14.58 11.79 14 69 11.88 14.90 12.06 15.13 12.24 15 35 36.1 14.64 11.85 14.75 11.94 14.97 12.11 15.19 12.30 15 42 36.2 14.71 11.90 14.81 11.99 15 03 12.16 15 25 12.35 15 48 36.3 14.77 11.95 14 88 12.04 15 09 12.22 15.32 12.40 15 54 36.4 14.83 12.00 14 94 12.09 15.16 12.27 15.38 12.45 15.61 36.5 14.89 12.05 15 00 12.14 15 22 12.32 15.44 12.50 15 67 36.6 14.96 12.10 15.06 12.19 15 28 12.37 15 51 12.56 15 73 36.7 15.02 12.15 15.13 12.24 15.35 12.42 15.57 12.61 15 80 36.8 15.08 12.20 15 19 12.29 15.41 12.47 15 63 12.66 15 86 36.9 15.14 12.25 15.25 12.34 15.47 12.53 15.70 12.71 15 92 37.0 15 20 12.30 15.31 12.40 15.53 12.58 15.76 12.77 15 99 37.1 15 27 12.36 15 38 12.45 15 60 12.63 15.82 12.82 16 05 37.2 15 33 12.41 15.44 12.50 15.66 12.68 15 89 12.87 16.11 37.3 15.39 12.46 15.50 12.55 15 72 12.73 15.95 12.92 16.18 37.4 15.45 12.51 15.56 12.60 15.79 12.78 16 01 12.97 16.24 37.5 15.51 12.56 15.63 12.65 15 85 12.84 16.08 13.03 16 30 37.6 15.57 12.61 15.69 12.70 15 91 12.89 16.14 13.08 16.37 37.7 15.64 12.66 15.75 12.75 15.97 12.94 16.20 13.13 16.43 37.8 15.70 12.71 15.81 12.81 16.04 12.99 16.26 13.18 16.49 37.9 15.76 12.76 15 88 12.86 16 10 13.04 16 33 13.23 16 56 XVI] Table. — Continued. 217 6 21° C. 22° C. 23° c. 24 C. 25 'C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE BEADING by by by by by by by by by weight volume weight volume weight volume weight volume weight 10.85 13.64 11.03 13.86 11.21 14 09 11.39 14 31 11.57 33.0 10.91 13.71 11.08 13.93 11.26 14.15 11.44 14.38 11.63 33.1 10.96 13 78 11.13 13.99 11.81 14.22 11.49 14.44 11.68 33.2 11.02 13 84 11.19 14.06 11.37 14 28 11.55 14 51 11.74 33.3 11.07 13 91 11.24 14.13 11.42 14.35 11.60 14.58 11.79 33.4 11.12 13.97 11.29 14.19 11.48 14.42 11.66 14.64 11.85 33.5 11.17 14 04 11.35 14.26 11.53 14 48 11.71 14.71 U.90 33.6 11.23 14.11 11.40 14 32 11.58 14.65 11.77 14 78 11.96 33.7 11.28 14.17 11.45 14 39 11.64 14.62 11.82 14 86 12.01 33.8 11.33 14.24 11.51 14.45 11.69 14.68 11.88 14 91 12.07 33.9 11.38 14 30 11.56 14.62 11.75 14.75 11.93 14.98 12.12 34.0 11. U 14.37 11.61 14.59 11.80 14.81 11.98 16 06 12.18 34.1 11.49 14.43 11.67 14 65 11.85 14.88 12.04 15.11 12.23 34.2 11.54 14.50 11.72 14.72 11.91 14.95 12.09 15.18 12.29 34.3 11.59 14.57 11.78 14.78 11.96 16.01 12.15 15.26 12.34 34.4 11.65 14.63 11.83 14.85 12.02 15.08 12.20 15 31 12.40 34.5 11.70 14.70 11.88 14.91 12.07 15 14 12.26 16.38 12.45 34.6 11.75 14.76 11.94 14.98 12.12 15 21 12.31 16 45 12.51 34.7 11.81 14.83 11.99 15 06 12.18 15 28 12.36 16 51 12.56 34.8 11.86 14.89 12.04 15.11 12.23 16.34 12.42 15 68 12.62 34.9 11.91 14.96 12.10 15 18 12.28 15.41 12.47 15.66 12.67 35.0 11.96 15.03 12.15 15.24 12.34 15.47 12.53 15 71 12.78 35.1 12.02 15.09 12.20 15.31 12.39 15 54 12.58 15 78 12.78 35.2 12.07 15.15 12.25 15 37 12. U 15 61 12.64 16 86 12.84 35.3 12.12 15 22 12.31 15.44 12.50 16 67 12.69 15 91 12.89 35.4 12.17 15 28 12.36 15 50 12.55 15.74 12.75 16 98 12.95 35.5 12.23 15.34 12.41 15.66 12.60 15.80 12.80 16 05 1.1.00 35.6 12.28 15.41 12.47 15 63 12.66 15.87 12.85 16 11 13.05 35.7 12.33 15.47 12.52 15 69 12.71 15 93 12.91 16 18 13.11 35.8 12.38 15.53 12.57 15.76 12.76 16 00 12.96 16 24 13.16 35.9 12.43 15.59 12.62 15 82 12.82 16 06 13.02 16 31 13.21 36.0 12.49 15 66 12.68 15.89 12.87 16.13 13.07 16 37 13.27 36.1 12.54 15 72 12.73 15 96 12.92 16 19 13.12 16.44 13.32 36.2 12.59 15 78 12.78 16.02 12.98 .16.26 13.18 16 50 13.37 36.3 12.64 15.85 12.84 16 08 13.08 16 32 13.23 16.56 13.43 36.4 12.70 15 91 12.89 16.15 13.08 16 39 13.28 16 63 18.48 36.5 12.75 15.97 12.94 16.21 18.14 16 45 13.34 16 69 13.5.3 36.6 12.80 16.04 12.99 16.28 13.19 16.52 13.39 16.76 13.59 36.7 12.85 16.10 13.05 16 34 13.24 16 58 18. U 16 82 13.64 36.8 12.91 16.16 13.10 16.40 13.29 16.65 13.49 16 89 13.70 36.9 12.96 16 23 13.15 16.47 13.35 16.71 13.55 16 95 13.75 37.0 18.01 16 29 13.20 16.53 18.40 16.77 13.60 17.02 18.80 37.1 IS. 06 16 35 13.26 16.60 13.45 16 84 13.65 17.08 13.86 37.2 13.11 16.42 13.31 16.66 13.50 16.90 13.71 17.15 13.91 37.3 13.16 16.48 13.36 16.72 18.56 16.97 13.76 17.21 13.96 37.4 IS. 21 16 54 13.41 16.79 13.61 17 03 13.81 17.27 14.02 37.5 1S.27 16.61 13.46 16.85 18.66 17.09 13.87 17.34 14.07 37.6 1S.S2 16 67 13.52 16.92 18.72 17.16 18.92 17.40 14.12 37.7 13.37 16.73 13.57 16.98 18.77 17.22 13.97 17.46 14.17 37.8 13.42 16.80 13.62 17.04 13.82 17.28 14.03 17.53 14.2s 37.9 218 METHODS OF ANALYSIS [Chap. 6 Table 17.— Alcohc 17.5 'C. 18° C. 19° C. 20° C. 21°C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cen by by by by by by by by by volume weight volume weight volume weight volume weight volume 38.0 15 82 12.81 15 94 12.91 16 16 13.09 16 39 13.28 16 62 38.1 15 88 12.86 16 00 12-96 16 22 13.14 16 46 13.33 16 68 38.2 15 94 12.91 16 06 13.01 16 29 13.19 16.51 13.38 16 75 38.3 16.01 12.96 16 12 13.06 16 35 13.25 16 57 13.44 16.81 38.4 16.07 IS. 02 16 18 13.11 16 41 13.30 16.64 13.49 16.87 38.5 16 13 13.07 16 25 13.16 16.47 13.35 16.70 13.54 16 94 38.6 16 19 IS. 12 16 31 13.21 16 53 13.40 16 76 13.59 17.00 38.7 16 25 13.17 16 37 13.26 16 60 13. 4S 16 83 13.64 17 06 38.8 16 31 13.22 16.43 13.31 16.66 13.50 16 89 13.69 17 13 38.9 16 37 13.27 16 49 13.37 16.72 13.55 16 95 13.74 17.19 39.0 16 44 13.32 16 55 13.42 16 78 13.61 17.01 13.79 17 25 39.1 16 50 13.37 16 61 13.47 16 84 13.66 17.07 IS. 85 17 31 39.2 16 56 13.42 16 67 13.52 16 91 13.71 17.14 13.90 17.38 39.3 16.62 13.47 16.74 13.57 16.97 13.76 17.20 13.95 17.44 39.4 16.68 IS. 52 16 80 13.62 17.03 IS. 81 17.26 14.00 17.60 39.5 16 74 13.57 16 86 13.67 17.09 13.86 17 32 14-05 17 56 39.6 16 80 13.62 16 92 13.72 17.15 13.91 17 39 14.10 17.63 39.7 16 87 13.68 16 98 13.77 17.21 13.96 17.45 14-15 17 69 39.8 16 93 13.73 17.04 13.82 17.28 14-02 17.51 14-21 17.75 39.9 16 99 13.78 17 10 13.87 17.34 14-07 17.57 14-26 17.81 40.0 17.05 13.83 17 16 13.92 17.40 14.12 17.63 14.31 17.88 40.1 17 11 13.88 17 23 13.98 17.46 14-17 17.70 14-36 17 94 40.2 17 17 13.93 17 29 14-03 17 52 14-22 17.76 14-41 18 00 40.3 17 23 13.98 17 35 14-08 17 58 14-27 17 82 14-46 18 06 40.4 17 29 14.03 17 41 14-13 17.64 14-32 17 88 14-51 18 12 40.5 17 35 14-08 17.47 14-18 17 71 14-37 17 94 14-56 18 19 40.6 17.41 14.13 17 53 14-23 17.77 14-42 18 01 14-62 18 25 40.7 17.48 14-18 17 59 14-28 17 83 14-47 18 07 14-67 18 31 40.8 17.54 14-23 17 65 14-33 17 89 14-52 18 13 14-72 18 37 40.9 17.60 14-28 17 71 14-38 17 95 14-57 18 19 14-77 18.43 41.0 17.66 14-33 17 77 14-43 18 01 14-62 18 25 14-82 18 49 41.1 17 72 14-38 17 84 14-48 18.07 14-68 18 31 14.87 18 56 41.2 17.78 14-43 17 90 14-53 18 13 14-73 18 37 14-92 18 62 41.3 17.84 14-48 17 96 14-58 18 20 14-78 18 44 14.97 18 68 41.4 17.90 14.53 18 03 14-63 18 26 14-83 18 50 15.03 18.74 41.5 17.96 14-58 18 08 14-68 18 32 14-88 18 56 15.08 18 80 41.6 18 02 14-63 18 14 14-73 18 38 14-93 18 62 15.13 18 86 41.7 18 08 14-68 18 20 14-78 18.44 14-98 18 68 15.18 18 93 41.8 18 14 14-73 18 26 14-83 18 50 15.03 18 74 15.23 18 99 41.9 18 20 14.78 18 32 14-88 18.56 15.08 18 81 15.28 19.05 42.0 18 27 14-83 18 38 14-93 18 62 15.13 18 87 15.38 19 11 42.1 18 33 14-88 18 44 14-98 18 68 15.18 18 93 15.38 19 17 42.2 18 39 14-93 18 50 15.03 18 74 15.23 18 99 15.43 19 23 42.3 18.45 14-98 18 56 15.08 18 80 15.28 19.05 15.48 19 29 42.4 18.51 15.03 18.62 15.13 18 87 15.33 19.11 15.53 19 36 42.5 18 57 15.08 18 68 15.18 18 93 15.38 19.17 15.58 19 42 42.6 18 63 15.13 18 75 15.23 18 99 15.43 19 23 15.63 19 48 42.7 18 69 15.18 18 81 15.28 19 05 15.48 19 29 15.69 19 54 42.8 18.75 15.23 18 87 15.33 19.11 15.53 19 36 15.74 19 60 42.9 18.81 15.28 18.93 15.38 19.17 15.58 19.42 15.79 19.66 XVI] WINES 219 Table- -Continued. 6 21 "C. 2: ^C. 23° c. 24 °C. 25 c. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per o«nt BCALE BEADINO by by by by by by by by by weight volume weight volume weight volume weight volume weight 75. 47 16 86 13.67 17.11 13.87 17.36 14. 08 17 69 14-28 38.0 IS. 53 16 92 13.72 17.17 13.93 17.41 14.13 17.66 14.33 38.1 IS. 58 16 99 13.78 17.23 13.98 17.47 14. 18 17.72 14.38 38.2 . IS. 63 17.05 13.83 17 30 14.03 17.54 14.23 17.78 14.4s 38.3 1 1S.G8 17.11 13.88 17.36 I4.O8 17.60 14.29 17.86 14.49 38.4 IS. 73 17.18 13.93 17,42 14.14 17.66 14.34 17.91 14-54 38.5 1 IS. 79 17 24 13.98 17.48 14.19 17.73 14.39 17 97 14.59 38.6 i 1S.8A 17 30 14.04 17.55 14.24 17 79 14.44 18.04 14.64 38.7 1 1S.89 17 36 14.09 17 61 14.29 17.86 14.49 18.10 14.70 38.8 1 lS.9i 17.43 14.14 17.67 14.34 17.92 14.66 18.16 14.75 38.9 \ IS. 99 17 49 14.19 17 74 14.40 17.98 14.60 18 23 14.80 39.0 1 14.05 17 55 14.24 17.80 14-45 18 04 14.65 18.29 14.85 39.1 ' M.JO 17 62 14.30 17.86 14-50 18 11 14.70 18.36 14.91 39.2 J4./5 17 68 14.35 17.92 14.55 18.17 14.76 18.42 14.96 39.3 ' U.20 17.74 14-40 17.99 14. 60 18 23 14.81 18.48 15.01 39.4 1J,.25 17 81 14.45 18 06 14.66 18 30 14.86 18 64 15.06 39.5 14. SO 17 87 14.50 18 11 14.71 18 36 14.91 18 61 15.12 39.6 , 14.S6 17 93 14.66 18.18 14.76 18 42 14.96 18.67 15.17 39.7 < 14.41 17.99 14-61 18.24 14. 81 18.48 15.02 18.73 15.22 39.8 \ 14. 46 18.06 14.66 18 30 14.87 18.56 15.07 18.80 15.27 39.9 \ 14.51 18 12 14.71 18 36 14.92 18 61 15.12 18 86 16. S2 40.0 ' 14.56 18 18 14.77 18.43 14.97 18.67 15.17 18.92 15.38 40.1 14-61 18 24 14.82 18.49 15.02 18.74 15.22 18 99 15.43 40.2 14.67 18 30 14.87 18 55 15.07 18 80 15.27 19 05 15.48 40.3 U.7S 18 37 14.92 18 61 15.12 18.86 15.33 19.11 15.53 40.4 14.77 18 43 14.97 18 68 15.17 18 92 15.38 19.18 15.59 40.5 14-82 18 49 15.03 18.74 15.23 18 99 15.43 19 24 15.64 40.6 14.87 18 55 15.08 18 80 15.28 19 06 15.48 19 30 15.69 40.7 14.92 18 61 15.13 18.86 15.33 19.11 15.53 19 37 15.74 40.8 14.97 18 68 15.18 18 93 15.38 19.18 16.59 19.43 15.80 40.9 15.03 18 74 15.2S 18.99 15.4s 19 24 15.64 19.49 15.85 41.0 15.08 18 80 15.28 19 06 15.48 19 30 15.69 19 56 15.90 41.1 16.13 18 86 15.83 19.11 15.53 19 36 15.74 19 62 15.95 41.2 16.18 18 93 15.38 19 17 15.58 19 43 15.79 19 68 16.01 41.3 16.23 18 99 15.4s 19 24 15.64 19.49 15.84 19 75 16.06 41.4 .16.28 19 05 15.48 19 30 15.69 19 55 15.90 19 81 16.11 41.5 16.33 19 11 15.53 19 36 15.74 19 61 15.95 19 87 16.16 41.6 16.38 19 17 15.58 19 42 15.79 19.68 16.00 19.94 16.21 41.7 15.43 19 23 15.63 19.48 15.84 19.74 16.05 20.00 16.27 41.8 15.48 19 29 15.69 19.66 16.89 19.80 16.10 20.06 16.32 41.9 15.53 19 36 15.74 19 61 15.94 19 86 16.16 20 13 16.37 42.0 16.58 19 42 15.79 19 67 15.99 19 93 16.81 20 19 16. 42 42.1 16.63 19 48 15.84 19.73 16.05 19 99 16.26 20 25 16.48 42.2 16.69 19 54 15.89 19.80 16.10 20.05 16.31 20 31 16.53 42.3 15.74 19 60 15.94 19.86 16.16 20 11 16. S6 20.38 16.58 42.4 16.79 19 66 15.99 19 92 16.20 20.18 16. 41 20 44 16.63 42.5 J 6. 84 19.72 16.04 19 98 16.25 20 24 16.47 20 50 16.79 42.6 15.89 19.79 16.09 20 04 16.30 20 30 16.52 20.57 16.74 42.7 115.94 19 85 16.14 20.10 16.35 20 36 16.57 20.63 16.79 42.8 16.99 19.91 16.19 20.17 16. 41 20.43 16.62 20.69 16.84 42.9 220 METHODS OF ANALYSIS 6 Table 17.— -Algo 17.5 C. 18° C. 19° C. 20° C. 21° ( SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Perc by by by by by by by by by volume weight volume weight volume weight volume weight volu 43.0 18.87 15. S3 18 99 15.43 19 23 15.63 19 48 15.84 19 7 43.1 18 93 15.S8 19 05 15.48 19 29 15.68 19,54 15.89 19 7 43.2 18.99 15. 4S 19.11 15.53 19 35 15.73 19 60 15.94 198 43.3 19 05 16.48 19 17 15.58 19.41 15.78 19.66 15.99 19 9 43.4 19 11 15.53 19 23 15.63 19.47 15.83 19.72 16.04 19.9 43.5 19 17 15.58 19 29 15.68 19 53 15.88 19 79 16.09 20 0 43.6 19 23 15.63 19 35 15.73 19 59 15.93 19 85 16.14 200 43.7 19 29 15.68 19.41 15.78 19 65 15.98 19.91 16.19 20.1 43.8 19 35 15.73 19.47 15.83 19.72 16.03 19 97 16.24 20 2 43.9 19 40 15.78 19 53 15.88 19.78 16.08 20.03 16.29 20 2 44.0 19.46 15.83 19 59 15.93 19 84 16.13 20 09 16.34 203 44.1 19.52 15.88 19 65 15.98 19.90 16.18 20.15 16.39 20 4 44.2 19 58 15.93 19 71 16.03 19.96 16.23 20.21 16. U 20 4 44.3 19.64 15.98 19 77 16.08 20 02 16.28 20.27 16.49 20 5 44,4 19 70 16.02 19 83 16.13 20.08 16.33 20 33 16.55 20 5 44.5 19.76 16.07 19 89 16.18 20.14 16.38 20.39 16.60 20 6 44 6 19 82 16.12 19 95 16.23 20.20 16.43 20.45 16.65 20 7 44.7 19 88 16.17 20 01 16.27 20 26 16.48 20 52 16.70 20 7 44.8 19 94 16.22 20.07 16.32 20 32 16.53 20.58 16.75 20 8 44.9 20.00 16.27 20.12 16.37 20 38 16.58 20.64 16.80 20 8 45.0 20 06 16.32 20 18 16.42 20.44 16.63 20 70 16.85 20 9 45.1 20.12 16.37 20.24 16.47 20 50 16.68 20 76 16.90 21 0 45.2 20.18 16.41 20 30 16.52 20 56 16.73 20 82 16.95 21 0 45.3 20.24 16.46 20 36 16.57 20 62 16.78 20 88 17.00 21 1 45.4 20 29 16.51 20 42 16.62 20 68 16.83 20.94 17.05 21 1 45.5 20 35 16.56 20.48 16.67 20.74 16.88 21.00 17.10 21 2 45.6 20 41 16.61 20 54 16.72 20 80 16.93 21 06 17.15 21 3 45.7 20 47 16.66 20 60 16.76 20 86 16.98 21 12 17.20 21 3 45.8 20 53 16.71 20 66 16.81 20 92 17.03 21.18 17.25 21 4 45.9 20 59 16.76 20.72 16.86 20.98 17.08 21.24 17.30 21.4 46.0 20 65 16.80 20.78 16.91 21 04 17.13 21.30 17.35 21 5 46.1 20 71 16.85 20 83 16.96 21 10 17.18 21.36 17.40 21 6 46.2 20 76 16.90 20 89 17.01 21 16 17.23 21.42 17.45 21 6 46.3 20 82 16.95 20.95 17.06 21 22 17.28 21.48 17.50 21 7 46.4 20 88 17.00 21.01 17.11 21 28 17.33 21.54 17.55 21 7 46.5 20.94 17.05 21 07 17.16 21 34 17.38 21.60 17.60 21 8- 46.6 21.00 17.10 21.13 17.21 21.40 17.43 21 66 17.65 21 9 46.7 21 06 17.15 21.19 17.26 21.46 17.48 21.72 17.70 21 9 46.8 21.12 17.20 21.25 17.31 21 52 17.53 21.78 17.75 22 0 46.9 21.18 17.25 21-31 17.36 21.58 17.58 21.84 17.80 22 0 47.0 21.24 17.30 21.37 17.41 21.64 17.63 21.90 17.85 22 1 47.1 21 30 17.35 21.43 17.46 21 70 17.68 21 96 17.90 22 2. 47.2 21.36 17.40 21.49 17.51 21.76 17.73 22.02 17.95 22 2' 47.3 21.42 17.45 21.55 17.56 21.82 17.78 22.08 18.01 22 3: 47.4 21.48 17.50 21.61 17.61 21.88 17.83 22.15 18.06 22 31 47.5 21.54 17.55 21.67 17.66 21.94 17.88 22 21 18.11 22.41 47.6 21.60 17.60 21 73 17.71 22.00 17.94 22.27 18.16 22.5: 47.7 21.66 17.65 21.79 17.76 22.06 17.99 22 33 18.21 22 5i 47.8 21.72 17.70 21.85 17.81 22.12 18.04 22.39 18.26 22. 6< 47.9 21.78 17.75 21.91 17.86 22.18 18.09 22.45 18.31 22. 7( XVI] Table. — Continued. 221 6 21° C. 22° C. 23° c. 24° c. 25° C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READINO bv by by by by by by by by weight volume weight volume weight volume weight volume weight 16.04 19 97 16.24 20 23 16.46 20 49 16.67 20.76 16.90 43.0 16.09 20 03 16.80 20 29 16.51 20 55 16.73 20 82 16.95 43.1 16.14 20 09 16.35 20 35 16.56 20 61 16.78 20 88 17.00 43.2 16.19 20 16 16.40 20 41 16.61 20 68 16.83 20 94 17.05 43.3 16. U 20 21 16.45 20.47 16.66 20.74 16.88 21 01 17.10 43.4 16.29 20 28 16.50 20 53 16.71 20 80 16.93 21 07 17.16 43.5 16.34 20 34 16.55 20 60 16.76 20 86 16.98 21 13 17.21 43.6 16.40 20 40 16.60 20 66 16.82 20 93 17.04 21 19 17.26 43.7 16.45 20 46 16.65 20 72 16.87 20 99 17.09 21.26 17.31 43.8 16.50 20 52 16.70 20 78 16.92 21 05 17.14 21 32 17.36 43.9 16.55 20 58 16.76 20 84 16.97 21.11 17.19 21 38 17.41 44.0 16.60 20 64 16.81 20 90 17.02 21 17 17.24 21.44 17.47 44.1 16.65 20 71 16.86 20 96 17.07 21 23 17.29 21 50 17.62 44.2 16.70 20.77 16.91 21 02 17.12 21 30 17.35 21.57 17.67 44.3 16.75 20 83 16.96 21 09 17.17 21 36 17.40 21 63 17.62 44.4 16.80 20 89 17.01 21 15 17.22 21 42 17.45 21 69 17.67 44.5 16.85 20 95 17.06 21 21 17.28 21.48 17.50 21.76 17.73 44.6 16.90 21 01 17.11 21 27 17.33 21 54 17.55 21.81 17.78 44.7 16.95 21 07 17.16 21 33 17.38 21.60 17.60 21 88 17.83 44.8 17.01 21 13 17.21 21 39 17.43 21 67 17.65 21 94 17.88 44.9 17.06 21 19 17.26 21 46 17.48 21.73 17.71 22 00 17.93 45.0 17.11 21 25 17.31 21 52 17.53 21 79 17.76 22.06 17.98 45.1 17.16 21 31 17.36 21 58 17.68 21 85 17.81 22 13 18.04 45.2 17. SI 21 37 17.41 21.64 17.63 21 91 17.86 22 19 18.09 45.3 17.26 21 43 17.46 21 70 17.68 21 98 17.91 22 25 18.14 45.4 17.31 21 49 17.51 21.76 17.73 22 04 17.96 22 32 18.20 45.5 17.36 21 55 17.56 21 82 17.79 22 10 18.02 22 38 18.25 45.6 17.41 21 61 17.61 21.88 17.84 22 16 18.07 22 45 18.30 45.7 17.46 21 67 17.66 21.94 17.89 22 23 18.12 22 51 18.36 45.8 17.51 21 73 17.71 22 01 17.94 22 29 18.17 22 67 18.41 45.9 17.56 21 79 17.76 22 07 17.99 22 36 18.23 22 64 18.47 46.0 17.61 21 85 17.81 22 13 18.04 22 42 18.28 22 70 18.62 46.1 17.66 21 91 17.86 22.19 18.09 22 48 18.33 22 76 18.57 46.2 17.71 21 97 17.91 22 26 18.15 22 54 18.39 22 83 18.63 46.3 17.76 22 03 17.96 22 32 18.20 22.61 18.44 22 89 18.68 46.4 17.81 22 09 18.01 22.38 18.25 22 67 18.49 22.96 18.73 46.5 17.86 22 16 18.06 22.44 18.30 22 73 18.55 23 02 18.79 46.6 17.91 22 22 18.11 22 51 18.36 22 80 18.60 23 08 18.84 46.7 17.96 22 28 18.17 22 57 18.41 22 86 18.65 23 16 18.90 46.8 18.01 22 34 18.22 22 63 18.46 22.92 18.70 23 21 18.95 46.9 18.06 22.41 18.27 22 69 18.51 22 99 18.76 23.28 19.00 47.0 18.11 22 47 18.32 22.76 18.57 23 05 18.81 23 34 19.06 47.1 18.16 22 53 18.38 22 82 18.62 23.12 18.86 23 41 19.11 47.2 18.21 22 59 18.43 22.88 18.67 23.18 18.92 23 47 19.16 47.3 18.26 22.66 18.48 22.94 18.72 23.24 18.97 23.64 19.22 47.4 18.31 22 72 18.53 23.01 18.78 23 31 19.02 23 60 19.27 47.5 18.36 22 78 18.58 23.07 18.83 23 37 19.08 23.67 19.33 47.6 18.42 22,84 18.64 23.13 IS. 88 23.44 19.13 23.73 19.38 47.7 1 18.47 22 91 18.69 23.20 18.93 23 50 19.18 23.80 19.43 47.8 1 18.52 22.97 18.74 23.26 18.99 23 66 19.24 23 86 19.49 47.9 222 METHODS OF ANALYSIS [Chap. 6 Table 17 — Alcoh 17.5 c. 18° C. 19° c. 20° c. 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per can by by by by by by by by by volume weight volume weight volume weight volume weight volum 48.0 21.84 17.80 21 97 17.91 22.24 18.14 22 61 18.36 22.76 48.1 21.90 17.85 22 03 17.96 22.30 18.19 22.57 18.41 22 82 48.2 21.96 17.90 22 09 18.01 22.36 18.24 22 63 18.46 22.88 48.3 22 02 17.95 22.15 18.06 22.42 18.29 22 69 18.51 22.94 48.4 22.08 18.00 22.21 18.11 22.48 18.34 22.75 18.56 23.01 48.5 22 14 18.05 22 27 18.16 22.64 18. S9 22.81 18.61 23 07 48.6 22 20 18.10 22.33 18.21 22 60 18.44 22 87 18.66 23 13 48.7 22 26 18.15 22 39 18.26 22.66 18.49 22 93 18.71 23.19 48.8 22.32 18.20 22.45 18.31 22.72 18.54 22 99 18.76 23.26 48.9 22.38 18.25 22.61 18.36 22.78 18.59 23.06 18.81 23.32 49.0 22.44 18. SO 22 57 18.41 22.84 18.64 23.12 18.86 23.38 49.1 22.60 18. S5 22 63 18.46 22.90 18.69 23 18 18.91 23.44 49.2 22.56 18.40 22.69 18.51 22 96 18.74 23 24 18.96 23.51 49.3 22.62 18.45 22.75 18.56 23.02 18.79 23 30 19.02 23.57 49.4 22.68 18.60 22.81 18.61 23.08 18.84 23 36 19.07 23 63 49.5 22.74 18.55 22.87 18.66 23.15 18.89 23.42 19.12 23 69 49.6 22.80 18.60 22.93 18.71 23 21 18.94 23.48 19.17 23.76 49.7 22.86 18.65 22.99 18.76 23 27 18.99 23 66 19.22 23.82 49.8 22.92 18.70 23.05 18.81 23 33 19.04 23.61 19.27 23.88 49.9 22 98 18.75 23.11 18.86 23 39 19.09 23.67 19.32 23.94 50.0 23.04 18.80 23 17 18.91 23 45 19.14 23.73 19.38 24.01 50.1 23.10 18.85 23 23 18.96 23.51 19.19 23.79 19.43 24.07 50.2 23 16 18.90 23 30 19.02 23 57 19.24 23 86 19.48 24 13 50.3 23 22 18.95 23 36 19.07 23 63 19.29 23.91 19.53 24.19 50.4 23.28 19.00 23 42 19.12 23.69 19.35 23.98 19.58 24 26 50.5 23 34 19.05 23.48 19.17 23.76 19.40 24.04 19.63 24 32 50.6 23 40 19.10 23.54 19.22 23 81 19.45 24.10 19.69 24.38 50.7 23 46 19.15 23.60 19.27 23 87 19.50 24.16 19.74 24.45 50.8 23 51 19.20 23.66 19.32 23 93 19.55 24 22 19.79 24.51 50.9 23 57 19.25 23.72 19.37 23.99 19.60 24.28 19.84 24.57 51.0 23.63 19. SO 23.78 19.42 24.06 19.65 24 36 19.89 24.64 51.1 23.69 19.35 23.84 19.47 24.12 19.70 24.41 19.94 24.70 51.2 23 75 19.40 23 90 19.52 24.18 19.75 24 47 20.00 24.76 51.3 23.81 19.45 23.96 19.57 24 24 19.80 24.53 20.05 24.82 51.4 23 87 19.50 24.02 19.62 24.30 19.85 24.69 20.10 24 89 51.5 23 93 19.55 24 08 19.67 24.36 19.90 24.66 20.15 24.95 51.6 23.99 19.60 24.14 19.72 24.42 19.95 24.72 20.20 26.01 51.7 24.05 19.65 24.20 19.77 24.48 20.01 24.78 20.26 26.07 51.8 24.11 19.70 24.26 19.82 24.64 20.06 24.84 20. SI 25.14 51.9 24.17 19.75 24.32 19.87 24.60 20.11 24.90 20.36 25.20 52.0 24 23 19.80 24.38 19.92 24.66 20.16 24.96 20.41 26.27 52.1 24.30 19.85 24.44 19.97 24.73 20.21 25.03 20.46 25.33 52.2 24.36 19.90 24.50 20.02 24.79 20.26 25.09 20.52 25 39 52.3 24.42 19.95 24.56 20.07 24.85 20.31 25.15 20.57 25.46 52.4 24.48 20.00 24.62 20.12 24.91 20.37 25,21 20.62 25.52 52.5 24.54 20.05 24.68 20.17 24.97 20.42 25.28 20.67 25.58 52.6 24.60 20.10 24.74 20.22 25.03 20.47 25.34 20.72 25.65 52.7 24.66 20.15 24.80 20.28 25.09 20.52 25.40 20.78 25.71 52.8 24.72 20.20 24.86 20.83 25.16 20.57 25.46 20.83 25.77 52.9 24.78 20.25 24.92 20.38 26.22 20.62 26.63 20.88 25.84 XVI] WINES 223 Table. — Continued. 6 21° C. 22° c. 23° C. 24° C. 25° C. Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight READING 18.57 18.62 \ 18.67 ■ 18.72 , 18.77 23.03 23.09 23 16 23 22 23 28 18.79 18.84 18.90 18.95 19.00 23 32 23 39 23.45 23.52 23.58 19.04 19.09 19.14 19.20 19.25 23.63 23.69 23.76 23 83 23.89 19.29 19.34 19.40 19.45 19.50 23 93 23.99 24 06 24.13 24.19 19.54 19.60 19.65 19.71 19.76 48.0 48.1 48.2 48.3 48.4 18.83 18.88 1 18.93 1 18.98 19.03 23 35 23.41 23 47 23 54 23.60 19.06 19.11 19.16 19.21 19.27 23.64 23 71 23 77 23.83 23.90 19.31 19.36 19.41 19.47 19.52 23 96 24 02 24.08 24.14 24.21 19.56 19.61 19.67 19.72 19.77 24.26 24.32 24 39 24.45 24.52 19.82 19.87 19.92 19.98 20.03 48.5 48.6 48.7 48.8 48.9 19.08 19.14 19.19 : 19.24 19.29 23 66 23 73 23 79 23 85 23.92 19.32 19.37 19.43 19.48 19.54 23.96 24.03 24.09 24.15 24.22 19.57 19.63 19.68 19.73 19.79 24.27 24.34 24 40 24.47 24.53 19.83 19.88 19.94 19.99 20.04 24.59 24 65 24.72 24.78 24.85 20.09 20.15 20.20 20.26 20.31 49.0 49.1 49.2 49.3 49.4 i 19.35 1 19.40 1 19.45 ; 19.61 19.56 23 98 24 04 24.11 24 17 24.24 19.59 19.64 19.70 19.75 19.80 24.28 24 35 24.41 24.48 24.54 19.84 19.89 19.95 20.00 20.05 24.60 24.66 24.73 24.79 24.86 20.10 20.15 20.21 20.27 20.32 24 91 24.98 25.05 25.11 25.18 20.87 20.42 20.48 20.54 20.59 49.5 49.6 49.7 49.8 49.9 19.61 i 19.66 : 19.72 • 19.77 19.82 24.30 24 37 24 43 24.49 24.66 19.86 19.91 19.96 20.02 20.07 24.61 24.67 24.74 24.80 24.86 20.11 20.16 20.22 20.27 20.33 24.92 24.99 25.05 25.12 25.18 20.38 20.43 20.49 20.54 20.60 25 25 25.31 25 38 25.45 25.51 20.65 20.70 20.76 20.82 20.87 50.0 50.1 50.2 50.3 50.4 19.87 19.93 19.98 80.03 SO 08 24.62 24.69 24.75 24.81 24.88 20.12 20.18 20.23 20.29 20.34 24.93 24.99 25.06 25.12 25.19 20.38 20.44 20.49 20.55 20.60 25.25 25.32 25 38 25.45 25 51 20.65 20.71 20.76 20.82 20.87 25 58 25 65 25.71 25.78 25.85 20.93 20.98 21.04 21.10 21.15 50.5 50.6 50.7 50.8 50.9 JO. 14 ,20.19 50.24 24 94 25.01 25 07 25.13 25.20 20.39 20.45 20.50 20.55 20.61 25.25 25 32 25.38 25.45 25.51 20.66 20.71 20.77 20.82 20.87 25 58 25.64 25 71 25.78 25.84 20. 9S 20.98 21.04 21.09 21.15 25.91 25 98 26 05 26.11 26.18 21.21 21.27 21.32 21.S8 21. U 51.0 51.1 51.2 51.3 51.4 .20.40 20.46 .20.51 20.56 \20.61 25 26 25 33 25.39 25.46 25.52 20.66 20 72 20.77 20.82 20.88 25.58 25 64 25 71 25.77 25.84 20.93 20.98 21.04 21.09 21.15 25 91 25 97 26.04 26 11 26.17 21.21 21.26 21.32 21.37 . 21.43 26 25 26 32 26 39 26 45 26 52 21.49 21.55 21.61 21.66 21.72 51.5 51.6 51.7 51.8 51.9 \i0.67 \20.72 20.77 20.83 .20.88 25 58 25 65 25 71 25.78 25.84 20.93 20.98 21.04 21.09 21.15 25.90 25.97 26.03 26.10 26 16 21.20 21.26 21.31 21.37 21.42 26.24 26 31 26.37 26.44 26.51 21.49 21.54 21.60 21.65 21.71 26 59 26 66 26 72 26 79 26 86 21.78 21.83 21.89 21.95 22.01 52.0 52.1 52.2 52.3 52.4 \20.9S '20.98 \21.04 \ 2 1.00 21.15 25.90 25.97 26.03 26.10 26.16 21.20 21.26 21.31 21.36 21.42 26 23 26.29 26.36 26.42 26.49 21.4S 21.53 21.59 21.64 21.70 26.57 26.64 26 71 26 77 26.84 21.77 21.82 21.88 21.93 21.99 26.93 26 99 27 06 27 13 27 20 22.06 22.12 22.18 22.24 22.29 52.5 52.6 52.7 52.8 52.9 1 224 6 METHODS OF ANALYSIS [Chap. Table 17.— Alcoh 17.5 °C. 18 o. 19' C. 20 C. 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cen by by by by by by by by by volume weight volume weight volume weight volume weight volum 53.0 24.84 20.30 24 98 20.43 25.28 20.68 25 59 20.93 25 90 53.1 24.90 20.36 25.04 20.48 25 34 20.73 25,65 20.98 25 96 53.2 24 96 m.4i 25 10 20.53 25.40 20.78 25,71 21.04 26 03 53.3 25 02 20.46 25,16 20.58 25.46 20.83 25,77 21.09 26 09 53.4 25.08 20.51 25.23 20.63 25.52 20.88 25,84 21.14 26.15 53.5 25.14 20.56 25 29 20.68 25.59 20.93 25 90 21.20 26.22 53.6 25 20 20.61 25 35 20.74 25.65 20.98 25 96 21.25 26 28 53.7 25 26 20.66 25.41 20.79 25.71 21.04 26 03 21.30 26 35 53.8 25 32 20.71 25,47 20.84 25.77 21.09 26 09 21.36 26.41 53.9 25 38 20.76 25 53 20.89 25 83 21.14 26,15 21.41 26 47 54.0 25.44 20.81 25,59 20.94 25 90 21.19 26 22 21.47 26 54 54.1 25 50 20.86 25,65 20.99 25.96 21.25 26 28 21.52 26 60 54.2 25 56 20.91 25 71 21.04 26 02 21.30 26 34 21.57 26 67 54.3 25 62 20.96 25 77 21.09 26 08 21.35 26,41 21.63 26 73 54.4 25 68 21.02 25,84 21.14 26.14 21.40 26.47 21.68 26 79 54.5 25.75 21.07 25 90 21.20 26 20 21.46 26 53 21.73. 26 86 54.6 25.81 21.12 25 96 21.25 26 27 21.51 26 59 21.79 26 92 54.7 25 87 21.17 26 02 21.30 26 33 21.56 26 66 21.84 26 99 54.8 25 93 21.22 26 08 21.35 26 39 21.62 26,72 21.90 27.05 54.9 26 99 21.27 26.14 21.40 26 45 21.67 26,78 21.95 27.11 55.0 26 05 21.32 26,20 21.45 26,52 21.72 26,85 22.00 27.18 55.1 26 11 21.37 26 26 21.51 26 58 21.77 26 91 22.05 27.24 55.2 26.17 21.43 26 32 21.56 26 64 21.83 26 97 22.11 27 31 55.3 26 23 21.48 26 38 21.61 26,70 21.88 27,04 22.16 27.37 55.4 26 29 21.53 26.45 21.66 26 76 21.93 27.10 22.21 27 43 55.5 26 35 21.58 26 51 21.71 26 83 21.98 27 16 22.26 27.49 55.6 26 41 21.63 26 57 21.76 26 89 22.04 27 23 22.32 27,55 55.7 26 47 21.68 26.63 21.81 26 95 22.09 27 29 22.37 27 62 55.8 26.53 21.73 26 69 21.87 27,01 22.14 27 35 22.42 27,69 55.9 26 59 21.79 26 75 21.92 27.07 22.19 27,41 22.48 27.75 56.0 26.65 21.84 26 81 21.97 27 14 22.24 27 48 22.53 27 82 56.1 26.72 21.89 26,87 22.02 27 20 22.30 27 54 22.58 27.88 56.2 26.78 21.94 26,93 22.07 27 26 22.35 27 60 22.64 27.94 56.3 26 84 21.99 26.99 22.12 27 32 22.40 27 66 22.69 28 01 56.4 26 90 22.04 27.05 22.18 27 38 22.45 27,73 22.74 28.07 56.5 26 96 22.09 27.12 23.23 27.44 22.50 27,79 22.79 28 14 56.6 27,02 22.14 27.18 22.28 27 51 22.56 27,85 22.85 28,20 56.7 27.08 22.19 27,24 22.33 27 57 22.61 27,91 22.90 28,26 56.8 27.14 22.25 27.30 22.38 27.63 22.66 27.98 22.95 28,33 56.9 27.20 22.30 27.36 22.43 27.69 22.71 ' 28.04 23.01 28 39 57.0 27.26 22.35 27.42 22.48 27 75 22.77 28.10 23.06 28 46 57.1 27 32 22.40 27 48 22.54 27 81 22.82 28.16 23.11 28 52 57.2 27 38 22.45 27.54 22.59 27.88 22.87 28.23 23.17 28 59 57.3 27.44 22.50 27.60 22.64 27.94 22.92 28.29 23.22 28 65 57.4 27 50 22.55 27.66 22.69 28.00 22.97 28 36 23.27 28.72 57.5 27.56 22.61 27.73 22.74 28.06 23.03 28.42 23.33 28.78 57.6 27 62 22.66 27.79 22.79 28.13 23.08 28.48 23.38 28 85 57.7 27.68 22.71 27.85 22.85 28.19 23.13 28.54 23.43 28 91 57.8 27.75 22.76 27.91 22.90 28.25 23.19 28.60 23.49 28 97 57.9 27.81 22.81 27.97 22.95 28.31 23.24 28.67 23.54 29.04 XVI] WINES 225 |TABLE. — Continued. 6 j 21- C. 22 C. 23 c. 24 c. 25 'C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weight volume weight volume weight volume weight volume weight 1 - ' SI. 20 26 23 21.47 26.56 21.75 26 91 22.05 27 27 22.35 53.0 SI .25 26 29 21.53 26.62 21.81 26 97 22.10 27 33 22.41 53.1 . SI. 31 26 35 21.58 26 69 21.86 27.04 22.16 27.40 22.47 53.2 1 S1.S6 26 42 21.64 26.75 21.92 27.11 22.22 27 47 22.52 53.3 ' SI. 42 26 48 21.69 26 82 21.97 27.17 22.27 27 64 22.58 53.4 1 SI. 47 26 55 21.74 26 88 2,2 . 03 27 24 22.33 27 61 22.64 53.5 SI. 52 26 61 21.80 26 95 22.08 27 31 22.39 27 67 22.70 53.6 S1.5R 26 68 21.85 27.01 22.14 27.38 22.44 27.74 22.75 53.7 SI 68 26 74 21.91 27 08 22.20 27.44 22.50 27 81 22.81 53.8 SI. 69 26 81 21.96 27 15 22.25 27 51 22.56 27.88 22.87 53.9 SI. 7 4 26 87 22.02 27 21 22.31 27 58 22.61 27 95 22.93 54.0 SI. 79 26 94 22.07 27 28 22.37 27 64 22.67 28 01 22.98 54.1 ' SI. 85 27 00 22.13 27 35 22.42 27 71 22.73 28 08 23.04 54.2 • SI. 90 27 07 22.18 27 41 22.48 27.78 22.78 28.15 23.10 54.3 1 SI. 96 27 13 22.24 27 48 22.53 27.85 22.84 28.22 28.16 54.4 \ SS.Ol 27 20 22.29 27 55 22.59 27 91 22.90 28 29 23.22 54.5 ' S2.06 27 26 22.35 27.61 22.65 27 98 22.95 28 36 23.27 54.6 I S2.12 27 33 22.40 27 68 22.70 28 05 28.01 28 43 23.33 54.7 1 SS.17 27 39 22.46 27.75 22.76 28 11 23.07 28 49 23 39 54.8 1 S2.23 27 46 22.51 27 81 22.81 28.18 23.13 28 56 28.45 54.9 j 2S.28 27 52 22.57 27 88 22.87 28 26 23.18 28 63 23.51 55.0 SS.S3 27 59 22.63 27 95 22.93 28 32 28.24 28 70 28.56 55.1 tS.S9 27 65 22.68 28 01 22.98 28 38 23.30 28.77 23.62 55.2 SS.44 27.72 22.74 28.08 23.04 28 45 28.35 28 84 23.68 55.3 SS.49 27 78 22.79 28 15 23.10 28.52 28.41 28 90 23.74 55.4 SS.55 27 85 22.85 28 21 23.15 28 58 23.47 28 97 23.80 55 . 5 i SS.60 27 92 22.90 28 28 23.21 28 65 23.63 29.04 23.86 55.6 ' S2.66 27 98 22.96 28 34 28 26 28.72 23.58 29 11 23.91 55.7 • ?■? 71 28 05 23.01 28 41 23.32 28.78 23.64 29 18 23.97 55.8 7f> 28.11 23.07 28.48 23.38 28.85 23.70 29 24 24.03 55.9 ' ^2 28 18 23.12 28.54 23.43 28.92 23.75 29 31 24.09 56.0 ■ 22.S7 28 24 23.18 28.61 23.49 28 99 23.81 29 38 24.14 56.1 1 S2.92 28 31 23.23 28.68 23.54 29 05 23.87 29.45 24.20 56.2 00 0,9 28 37 23.29 28.74 23.60 29.12 23.93 29.52 24.26 56.3 ■ ■'.? 28.44 23.34 28 81 23.66 29 19 23.98 29 58 24.32 56.4 -•) 09 28 50 23.40 28 87 23.71 29 26 24.04 29 65 24.38 50.5 ■ SS.14 28.56 23.45 28.94 23.77 29 32 24.10 29.72 24.4s 56.6 ' Sf!.20 28 63 23.51 29 01 23.88 29 39 24.15 29 79 24.49 56.7 "" ^5 28.69 23.56 29 07 23.88 29.46 24.21 29 86 24.55 56.8 ;/ 28 76 23.62 29 14 23.94 29.53 24.27 29 93 24. 61 56.9 7? 28 82 23.67 29.20 23.99 29 59 24.32 29 99 24.66 57.0 ■•) 28 89 23.73 29 27 24.05 29 66 24.38 30 06 24.72 57.1 '- 28 95 23.78 29 34 24.11 29 73 24-44 30 13 24.78 55.2 , .*S.5l' 29 02 23.84 29 40 24.16 29 80 24.49 30 20 24.84 55.3 ! SS.5S 29 08 23.90 29.47 24.22 29.86 24.55 30 27 24.90 57.4 ' SS.63 29 15 23.95 29 53 24.27 29 93 24.61 30 34 24.95 57.5 \ 2S.69 29 21 24.01 29.60 24.33 30 00 24.66 30.41 25.01 57.6 1 iS.74 29.28 24.06 29.66 24.39 30.07 24.72 30 48 25.07 57.7 1 W.80 29.34 24.12 29.73 24.44 30.14 24.78 30.66 25. IS 57.8 ' SS.85 29 41 24.17 29.80 24.50 30.20 24.8S 30.62 25.19 57.9 1 226 METHODS OF ANALYSIS 1 [Chap. 6 Table 17.— AlcohoiI 17.5 °C. 18 C. 19 c. 20 c. 21° C. SCALE READINO Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 58.0 27 87 22.86 28,03 23.00 28.38 23.29 28 73 23.59 29.10 68.1 27 93 22.91 28 09 23.05 28.44 23.34 28.79 23.65 29.17 58.2 27.99 22.96 28,15 23.10 28 50 23.40 28 86 23.70 29.23 58.3 28 05 23.02 28,21 23.16 28.56 23.45 28 92 23.75 29 29 58.4 28.11 23.07 28,28 23.21 28.62 23.50 28.98 23.81 29.36 58.5 28.17 23.12 28.34 23.26 28,69 23 56 29,04 23.86 29 42 58.6 28 23 23.17 28,40 23.31 28 75 23.61 29,11 23.91 29.48 58.7 28.29 23.22 28 46 23.36 28,81 23.66 29,17 23.97 29 55 58.8 28 35 23.27 28 62 23.41 28,88 23.71 29 23 24.02 29.61 58.9 28.41 23.32 28,58 23.47 28.94 23.77 29 30 24. 08 29.68 59.0 28 47 23.37 28,64 23.52 29 00 23.82 29 36 24.1s 29 74 59.1 28,63 23.43 28,71 23.57 29 06 23.87 29,42 24. 18 29 80 59.2 28 69 23.48 28,77 23.62 29.12 23.93 29,49 24.24 29 87 59.3 28 65 23.53 28.83 23.67 29.19 23.98 29,55 24.29 29 93 59.4 28.71 23.58 28.89 23.73 29.25 24-03 29.61 24.34 29,99 59.5 28.78 23.63 28.95 23.78 29 31 24-08 29 68 24.40 30 06 59.6 28 84 23.68 29.01 23.83 29 37 24-14 29.74 24.45 30 13 59.7 28 90 23.73 29,07 23.88 29.43 24-19 29 80 24.50 30 19 59.8 28 96 23.79 29 13 23.93 29 50 24-24 29.87 24.56 30 26 59.9 29,02 23.84 29 20 23.98 29 56 24-30 29.93 24. 61 30 32 . 60.0 29,08 23.89 29 26 24.04 29,62 24-35 29 99 24.67 30.39 60.1 29,14 23.94 29 32 24.09 29 68 24.40 30 06 24.72 30 45 ' 60.2 29,20 23.99 29 38 H.I4 29,74 24.46 30 12 24.77 30 52 60.3 29,26 24.04 29 44 24.19 29,81 24-51 30 19 24.83 30 59 60.4 29,32 24.10 29 60 24.25 29,87 24-56 30.26 24.88 30 65 60.5 29 38 24.15 29 56 24.30 29.93 24-61 30 32 24.94 30 72 60.6 29 45 24.20 29 63 24.35 29 99 24-67 30.38 24.99 30 78 60.7 29 51 24.25 29 69 24.40 30 06 24-72 30.46 25.04 30 85 60.8 29 57 24.30 29 75 24.46 30.12 24-77 30.61 25.10 30 91 60,9 29,63 24-35 29.81 24.51 30.18 24-83 30 67 25.16 30 98 61.0 29,69 24.41 29 87 24.56 30 26 24-88 30,64 25.21 31 05 61.1 29 75 24.48 29 93 24-61 30.31 24.93 30 70 25.27 31 11 61.2 29,81 24-51 29 99 24.66 30 38 24.98 30 77 25.32 31 18 61.3 29 87 24.56 30 06 24-72 30.44 25.04 30 83 25.38 31 25 61.4 29,93 24. 61 30 12 24-77 30.50 25.09 30 90 25.44 31 32 61.5 29 99 24.67 30 18 24-82 30 67 25.15 30,98 25.49 31 39 61.6 30 06 24.72 30 25 24-87 30.63 25.20 31.03 25.55 31 45 61.7 30,12 24.77 30 31 24.93 30.69 25.26 31 09 25.60 31 52 61.8 30,18 24.82 30 37. 24-98 30 76 25.31 31,16 25.66 31.59 61.9 30,25 24.88 30,44 25.03 30.82 25.37 31,23 25.71 31,66 62.0 30 31 24.93 30 50 25.09 30 89 25.43 31.29 25.77 31 72 62.1 30 37 24.98 30 56 25.14 30.96 25.48 31 36 25.83 31 79 62.2 30,43 2>.0S 30 63 25.20 31 01 25.54 31 43 25.88 31 86 62.3 30,60 25.09 30 69 25.25 31 08 25.59 31 49 25.94 31 93 62.4 30.66 25.14 30 75 25.31 31.14 25.65 31 66 25.99 31,99 62.5 30 62 25.20 30 82 25.36 31 21 25.70 31 63 26.05 32 06 62.6 30 69 25.25 30 88 25.42 31.28 25.76 31 69 26.11 32 13 62,7 30.75 2-5.31 30 94 25.47 31.34 25.81 31,76 26.17 32 20 62.8 30 81 25.36 31 01 25.53 31.41 25.87 31 83 26.23 32 27 62.9 30.87 25.42 31,07 25.58 31.47 25.92 31,89 26.29 32.34 1 XVI] Dable. — Continued. 227 6 21°C. 22 •c. 23 C. 24 C. 25 C. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent BCALB READINO by by by by by by by by by weight volume weight volume weight volume weight volume weight S3. 91 29.47 24.23 29.87 24.55 30 27 24.89 30 69 25.25 58.0 23.96 29.54 24-28 29.93 24. 61 30.34 24.95 30 76 25.31 58.1 2^.02 29 60 24.34 29.99 24.66 30.41 25.01 30 83 25.37 58.2 U.07 29.67 24.39 30.06 24.72 30.48 25.07 30.90 25.43 58.3 24.13 29.73 24.45 30.13 24.78 30.54 25.13 30.97 25.49 58.4 24.18 29 80 24-50 30 20 24.83 30.61 25.18 31 04 25.55 58.5 24.23 29.86 24-56 30 26 24.89 30.68 25.23 31.11 25.61 58.6 24.29 29 93 24-61 30 33 24.94 30.75 25.29 31.18 25.67 58.7 24.34 29.99 24-67 30.40 25.00 30 82 25.35 31.25 25.73 58.8 24.40 30.06 24-72 30.47 25.06 30.88 25.41 31.32 25.80 58.9 24.45 30 13 24.78 30.53 25.12 30.95 25.47 31 40 25.86 59.0 24.51 30.19 24-83 30 60 25.18 31.02 25.53 31.47 25.92 59.1 24-56 30.26 24-89 30.67 25.24 31.09 25.59 31.54 25.98 59.2 24.61 30 33 24.95 30.74 25.30 31.16 25.65 31 61 26.04 59.3 24.67 30 39 25.00 30 81 25.36 31 23 25.71 31.68 26.10 59.4 24-72 30.46 25.06 30.87 25.41 31.30 25.77 31.76 26.16 59.5 24-78 30 53 25.11 30.94 25.47 31 38 25.83 31 83 26.23 59.6 24-83 30.59 25.17 31.01 25.53 31 45 25.89 31 90 26.29 59.7 24-89 30.66 25.23 31.08 25.59 31.52 25.95 31.97 26.35 59.8 24.94 30 73 25.29 31.15 25.65 31.59 26.02 32 04 26.42 59.9 24.99 30 79 25.84 31.22 25.71 31.66 26.08 32.12 26.48 60.0 25.05 30 86 25.40 31.29 25.77 31 73 26.14 32.19 26.54 60.1 25.11 30 93 25.46 31 36 25.83 31 80 26.20 32.27 26.61 60.2 25.16 30 99 25.52 31.43 25.89 31 87 26.27 32 34 26.67 60.3 25.22 31.06 25.57 31.60 25.95 31 94 26.33 32 41 26.73 60.4 25.28 31 13 25.63 31.57 26.01 32 02 26.39 32 49 26.80 60.5 25.34 31 20 25.69 31.64 26.07 32 09 26.45 32.56 26.86 60.6 25.59 31 27 25.75 31.71 26.13 32 16 26.52 32.64 26.92 60.7 25.45 31 33 25.80 31.78 26.19 32 23 26.58 32.71 26.99 60.8 25.51 31.40 25.86 31.85 26.25 32.30 26.64 32.78 27.05 60.9 25.56 31 47 25.92 31.92 26. SI 32 38 26.70 32 86 27 12 61.0 25.62 31 54 25.98 31.99 26.37 32 45 26.76 32.93 27.18 61.1 25.68 31 61 26.04 32.06 26.43 32.52 26.83 33 01 27.24 61.2 25.73 31.67 26.10 32.13 26.49 32 59 26.89 33 08 27.31 61.3 25.79 31.74 26.16 32.20 26.55 32.67 26.95 33 16 27.37 61.4 25.85 31 81 26.22 32.27 26.61 32 74 27.01 33 23 27. U 61.5 25.90 31 88 26.28 32 34 26.67 32 81 27.08 33 31 27.50 61.6 25.96 31.95 26.34 32.41 26.73 32.88 27.14 33 38 27.56 61.7 26.02 32.01 26.40 32.49 26.79 32.96 27.20 33 46 27.63 61.8 26.08 32 09 26.46 32.56 26.85 33 03 27.27 33 53 27.69 61.9 26.14 32.16 26.51 32 63 26.92 33 10 27.33 33 60 27.76 62.0 26.20 32.23 26.57 32.70 26.98 33 18 27.39 33 68 27.82 62.1 26.25 32 30 26.63 32.77 27.04 33 25 27.46 33.75 27.88 62.2 26.31 32 37 26.69 32.84 27.10 33 33 27.52 33 83 27.95 62.3 26.37 32.44 26.75 32.91 27.16 33.40 27.58 33 90 28.01 62.4 26.43 32.51 26.81 32.99 27.23 33 47 27.65 33 98 28.08 62.5 26.49 32.68 26.87 33 06 27 29 33.55 27.71 34 05 28.15 62.6 26.55 32.65 26.93 33.13 h'.h 33.62 27.77 34 13 28.22 62.7 26.61 32.72 26.99 33.20 27.41 33.70 27.84 34 21 28.28 62.8 26.67 32.79 27.06 33.28 27.48 33.77 27.90 34 29 28.35 62.9 228 METHODS OF ANALYSIS [Chap. 6 Table 17.- Alcohol 17.5 -c. 18° C. 19 c. 20° c. 21° c SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 63.0 30 94 2547 31.14 25.64 31.54 25.98 31.96 26.35 32.41 63.1 31 GO 25.52 31 20 25.69 31.61 26.03 32.03 26.41 32 48 63.2 31 06 25.58 31 26 25.75 31.67 26.09 32.10 26.46 32 55 63.3 31 13 25.63 31 33 25.80 31 74 26.15 32 17 26.52 32.62 63.4 31 19 25.69 31 39 25.86 31 80 26.21 32 23 26.58 32 69 63.5 31.26 25.74 31.46 25.91 31 87 26.26 32 30 26.64 32 76 63.6 31 32 25.80 31.52 25.97 31 93 26.32 32 37 26.70 32 83 63.7 31 38 25.85 31.59 26.02 32 00 26.38 32.44 26.76 32.90 63.8 31 45 25.91 31 65 26.08 32 07 26.44 32 51 26.82 32.97 63.9 31 51 25.96 31 72 26.13 32 13 26.49 32 58 26.88 33 04 64.0 31 58 26.02 31 78 26.19 32 20 26.55 32 66 26.94 33 11 64.1 31 64 26.07 31 85 26.25 32 27 26.61 32 72 26.99 33 18 64.2 31 70 26.13 31.91 26.30 32 34 26.67 32 79 27.05 33 25 64.3 31 77 26.18 31 97 26.36 32.40 26.72 32 86 27.11 33 32 64.4 31 83 26.24 32.04 26.41 32.47 26.78 32 92 27.17 33 39 64.5 31 90 26.29 32 11 26.47 32.54 26.84 32 99 27.23 33.46 64.6 31 96 26.35 32.17 26.53 32.60 26.90 33 06 27.29 33 53 64.7 32 03 26.40 32.24 26.58 32.67 26.95 33 13 27.35 33 60 64.8 32 09 26.46 32.30 26.64 32 74 27.01 33 20 27.41 33.67 64.9 32 16 26.51 32 37 26.69 32 81 27.07 33 27 27.47 33.74 65.0 32 22 26.57 32 43 26.75 32 87 27.13 33 34 27.53 33 82 65.1 32 29 26.63 32.50 26.80 32.94 27.19 33 41 27.59 33 89 65.2 32 35 26.68 32 57 26.86 33.01 27.25 33.48 27.65 33.96 65.3 32 42 26.74 32 63 26.92 33 08 27.31 33 55 27.71 34 03 65.4 32 48 26.79 32 70 26.97 33 15 27.37 33 62 27.77 34 10 65.5 32 55 26.85 32.76 27.03 33 22 27.43 33 69 27.83 34.18 65.6 32 61 26.90 32 83 27.09 33 28 27.49 33 76 27.89 34 25 65.7 32 68 26.96 32.89 27.15 33 35 27.54 33 83 27.95 34.32 65.8 32 75 27.01 32 96 27.21 33 42 27.60 33.90 28.01 34 40 65.9 32.81 27.07 33 03 27.26 33 49 27.66 33 97 28.07 34.47 66.0 32.88 27.13 33.10 27.32 33 56 27.72 34.04 28.13 34.54 66.1 32.94 27.19 33 17 27.38 33 63 27.78 34.11 28.19 34.62 66.2 33 01 27.25 33 23 27.44 33 70 27.84 34.18 28.26 34.69 66.3 33 07 27.30 33 30 27.50 33 77 27.90 34.25 28.32 34.76 66.4 33 14 27.36 33 37 27.56 33 84 27.96 34 33 28.38 34.84 66.5 33.21 27.42 33 44 27.62 33.91 28.02 34.40 28.45 34 91 66.6 33 28 27.48 33 51 27.68 33.98 28.08 34.47 28.51 34.99 66.7 33 35 27.54 33 58 27.73 34 05 28.14 34.54 28.57 35 06 66.8 33 41 27.60 33 65 27.79 34 12 28.20 34.62 28.64 35.14 66.9 33 48 27.65 33 72 27.85 34.19 28.27 34.69 28.70 35 21 67.0 33 55 27.71 33 79 27.91 34 26 28.33 34.76 28.76 35 29 67.1 33 62 27.77 33 86 27.97 34.34 28.39 34.83 28.82 36 37 67.2 33 69 27.83 33 92 28.03 34.41 28.45 34.91 28.89 35 44 67.3 33.76 27.89 33.99 28.09 34 48 28.52 34.98 28.95 35.52 67.4 33 82 27.95 34 06 28.15 34 55 28.58 35 05 29.01 35 60 67.5 33 89 28.01 34 13 28.21 34.62 28.64 35.13 29.08 35 67 67.6 33 96 28.06 34.20 28.27 34.69 28.70 35 20 29.14 35.75 67.7 34 03 28.12 34.27 28.34 34.76 28.76 35.28 29.21 36.82 67.8 34.09 28.18 34.34 28.40 34.84 28.83 35 35 29.27 35 90 67.9 34 16 28.24 34 41 28.46 34.91 28.89 35.43 29.34 35.98 XVI] Table. — Continued. 229 6 21° C. 22° C. 23° C. 24° c. 25 C. Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by, weight Per cent by volume Per cent by weight SCAJCE RE.VDINQ i6.73 32 87 27.12 33 35 27.54 33 84 27.96 34 36 28.42 63.0 J16.79 32.94 27.18 33 42 27.60 33 92 28.03 34.44 28.49 63.1 £6.85 33 01 27.24 33.50 27.66 33 99 28.09 34 52 28.55 63.2 26.91 33 08 27.31 33 57 27.72 34.07 28.16 34.60 28.62 63.3 26.96 33 15 27.37 33 64 27.79 34.15 28.23 34.67 28.69 63.4 27.02 33 22 27.43 33 72 27.85 34 22 28.29 34 75 28.76 63.5 27.09 33 30 27.49 33 79 27.91 34 30 28.36 34.83 28.82 63.6 27.15 33 37 27.56 33.86 27.98 34 38 28.43 34 91 28.89 63.7 27. ei 33 44 27.62 33 93 28.04 34.46 28.49 34 98 28.96 63.8 27.27 33 51 27.68 34.01 28.11 34 53 28.56 35 07 29.03 63.9 27.38 33 59 27.74 34.08 28.17 34 61 28.63 35 15 29.10 64.0 27.39 33 66 27.81 34.16 28.24 34 68 28.69 35 23 29.17 64.1 27.45 33 73 27.87 34 23 28.30 34.76 28.76 35 31 29.24 64.2 27.51 33 80 27.93 34 31 28.37 34.84 28.83 35 39 29.31 64.3 27.57 33 88 27.99 34 39 28.43 34 92 28.89 35 48 29.38 64.4 27.63 33 95 28.06 34.46 28.50 34 99 28.96 35 56 29.45 64.5 27.70 34 02 28.12 34.54 28.57 35 07 29.03 35 64 29.52 64.6 27.76 34 10 28.19 34.61 28.63 35 15 29.10 35.72 29.60 64.7 27.82 34.17 28.25 34 69 28.70 35.23 29.17 35 80 29.67 64.8 27.88 34.24 28.31 34.76 28.76 35 31 29.24 35.89 29.74 64.9 27.94 34 32 28.38 34 84 28.83 35 39 29.31 35 97 29.81 65.0 28.00 34 39 28.44 34.92 28.89 35.47 29.38 36 05 29.88 65.1 28.06 34.47 28.51 34 99 28.96 35 55 29.44 38 13 29.95 65.2 28.13 34 54 28.57 35 07 29.03 35 63 29.51 36 21 30.02 65.3 28.19 34 61 28.63 35.15 29.10 35.71 29.58 36 30 30.10 65.4 28.25 34.69 28.70 35 23 29.16 35.79 29.65 36 38 30.17 65.5 28.32 34 76 28.76 35 30 29.23 35 87 29.72 36 46 30.24 65.6 28.38 34.84 28.83 35 38 29.30 35 94 29.79 36 55 30.32 65.7 28.45 34 91 28.89 35 46 29.37 36 02 29.86 36 63 30.39 65.8 88.51 34 99 28.96 35 54 29.44 36.11 29.93 36.71 30.46 65.9 28.57 35 06 29.02 35 62 29.51 36 19 30.00 36 79 30.54 66.0 28.64 35 14 29.09 35 70 29.58 36 27 30.07 36 88 30.61 66.1 28.70 35 22 29.16 35.77 29.64 36 35 30.15 36 96 30.68 66.2 28.76 35 30 29.23 35 85 29.71 36 43 30.22 37 04 30.76 66.3 28.83 35 38 29.29 35 93 29.78 36.52 30.29 37 13 30.83 66.4 28.89 35 45 29.36 36 01 29.85 36.60 30.36 37 22 30.90 66.5 28.96 35 53 29.43 36 09 29.92 36 68 30.43 37 30 30.98 66.6 29.03 35 61 29.50 36.17 29.99 36.76 30.51 37 39 31.05 66.7 29.09 35 69 29.57 36.25 30.06 36 84 30.58 37 48 31.13 66.8 29.15 35.77 29.64 36 33 30.13 36 93 30.65 37 57 31.21 66.9 29.22 35 84 29.71 36 41 30.20 37.01 30.72 37 65 31.28 67.0 29.29 35 92 29.77 36 49 30.27 37 09 30.80 37 74 31.36 67.1 29.35 36 00 29.84 36 57 30.34 37 18 30.87 37 83 31. U 67.2 29.42 36.08 29.91 36 65 30.41 37.26 30.94 37.91 31.51 67.3 29.49 36 16 29.98 36 73 30.49 37 35 31.02 38 00 31.59 67.4 29.55 36 24 30.05 36 81 30.56 37.44 31.09 38 09 31.65 67.5 29.62 36 32 SO. 12 36.90 30.63 37.52 31.17 38 18 31.74 67.6 29.69 36 40 30.19 36 98 30.70 37.61 31.24 38 26 31.82 67.7 29.75 36 48 30.26 37 06 30.77 37 69 31.32 38 35 31.89 67.8 29.82 36.56 30.33 37.14 30.84 37.78 31.39 38.44 31.97 67.9 230 METHODS OF ANALYSIS [Chap. 6 Table 17 — -Alcghq] 17.5 °C. 18° C. 19° c. 20° c. 21° C. SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent by by by by by by by by by volume weight volume weight volume weight volume weight volume 68.0 34.23 28.30 34.48 28.52 34.98 28.95 35 60 29.41 36 06 68.1 34.30 28.36 34.55 28.58 35 05 29.01 35 57 29.47 36.13 68.2 34.36 28.42 34.62 28.64 35.13 29.08 35.65 29.54 36 21 68.3 34 43 28.48 34.69 28.70 35.20 29.14 35.72 29.60 36.29 68.4 34.50 28.54 34.76 28.76 35.27 29.21 35.80 29.67 36 37 68.5 34.57 28.59 34.83 28.82 35 35 29.27 35 87 29.73 36 46 68.6 34.64 28.65 34.90 28.88 35.42 29.33 36.96 29.80 36.62 68.7 34.70 28.71 34.97 28.95 35.49 29.40 36.02 29.86 36 60 68.8 34.77 28.77 35 04 29.01 35.57 29.46 36.10 29.93 36.68 68.9 34.84 28.83 35 12 29.07 35.64 29.53 36.18 29.99 36.76 69.0 34 91 28.89 35.19 29.13 35.71 29.59 36.26 30.06 36.84 69.1 34.97 28.95 35.26 29.19 35.79 29.65 36 33 30.13 36.91 69.2 35 04 29.01 35 33 29.26 35.86 29.72 36.41 30.20 36 99 69.3 35.12 29.07 35.40 29.32 35 93 29.78 36.48 30.27 37.07 69.4 35 19 29.14 35.47 29.38 36.01 29.85 36.66 30.33 37.16 69.5 35.27 29.20 35 56 29.45 36.08 29.91 36.64 30.40 37.24 69.6 35 34 29.26 35.62 29.51 36.16 29.97 36.72 30.47 37 32 69.7 35 41 29.33 35.69 29.57 36 23 30.04 36.79 30.54 37.40 69.8 35.49 29.39 35.76 29.64 36.31 30.11 36.87 30.61 37.48 69.9 35 56 29.46 35 83 29.70 36.39 30.17 36.96 30.67 37.56 70.0 35 64 29.52 35.91 29.76 36.46 30.24 37 02 30.74 37.64 70.1 35 71 29.59 35 98 29.82 36 54 30.31 37 10 30.81 37.72 70.2 35.78 29.65 36 05 29.89 36 61 30.38 37.19 30.88 37.80 70.3 35.86 29.72 36 13 29.95 36 69 30.44 37 27 30.95 37.89 70.4 35.93 29.78 36.20 30.01 36.76 30.51 37 36 31.01 37.97 70.5 36 01 29.85 36.28 30.08 36.84 30.58 37.43 31.09 38 06 70.6 36.08 29.91 36 35 30.15 36.92 30.64 37.61 31.16 38.13 70.7 36 16 29.97 36 43 30.21 36 99 30.71 37 59 31.23 38.22 70.8 36 23 30.04 36 50 30.28 37 07 30.78 37.67 31.30 38 30 70.9 36 31 30.11 36.58 30.35 37.15 30.85 37 76 31.37 38 38 71.0 36 38 30.17 36 65 30.41 37 23 30.91 37.83 SI. 44 38.47 71.1 36 46 30.24 36.73 30.48 37.31 30.98 37 91 31.51 38 66 71.2 36 53 30.30 36.80 30.55 37.39 31.05 37.99 31.59 38 63 71.3 36 60 30.37 36.88 30.61 37.47 31.12 38 07 31.66 38.72 71.4 36.68 30.44 36.95 30.68 37.55 31.19 38.16 31.73 38 80 71.5 36 75 30.50 37 03 30.75 37.63 31.26 38 24 31.80 38.88 71.6 36 83 30.57 37.11 30.81 37.71 31.33 38 32 31.87 38.97 71.7 36.90 30.64 37.19 30.88 37.79 31.40 38 40 31.94 39 05 71.8 36.98 30.70 37.27 30.95 37.87 31.47 38 49 32.01 39.14 71.9 37.05 30.77 37 34 31.01 37.94 31.54 38 57 32.09 39 23 72.0 37.13 30.84 37.42 31.08 38.02 31.61 38 66 32.17 39.31 72.1 37 21 30.90 37 50 31.15 38.11 31. 6S 38.74 32.24 39.40 72.2 37 29 30.97 37.58 31.22 38.19 31.75 38.82 32.32 39.49 72.3 37 36 31.03 37.66 31.29 38 27 31.82 38.90 32.39 39 67 72.4 37 44 31.10 37 73 31.36 38 35 31.89 38.98 32.47 39.66 72.5 37.52 31.17 37.81 31.42 38.43 31.96 39 07 32.54 39.76 72.6 37 60 31.24 37.89 31.49 38.51 32.04 39 16 32.62 39.83 72.7 37.67 31.31 37 97 31.56 38 59 32.11 39.24 32.69 39.92 72.8 37.75 31.37 38 05 31.63 38 67 52.18 39 33 32.77 40.01 72.9 37 83 31.44 38 13 31 . 70 38.76 32.26 39 41 32.84 40.10 XVI] 231 Table- -Continued. 6 21° C. 22° C. 23° C. 24° c. 25° c. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weiffht volume weight volume weight volume weight volume weight 29 . 89 36 63 30.40 37 23 30.91 37 86 SI. 47 38 53 32.05 68.0 29 ,9-5 36 71 30.47 37 31 30.99 37 95 31.54 38.61 32.13 68.1 SO 02 36 79 30.54 37 39 31.06 38 03 31.62 38 70 32.21 68.2 SO. 09 36 87 30.61 37 48 31.13 38.12 31.69 38 79 32.29 68.3 SO. 16 36 96 30.68 37.56 31.21 38 21 31.77 38.88 82.87 68.4 SO. 2^ 37 03 30.75 37 65 31.28 38 30 31.84 38.96 32.45 68.5 SO . HO 37 12 30.82 37 73 31.35 38 38 31.92 39 06 32.53 68.6 SO. 37 37 20 30.89 37 82 31.43 38 47 31.99 39 15 32.61 68.7 SO 43 37 28 30.96 37 90 31.50 38 56 32.07 39.24 82.69 68.8 SO. 50 37 36 81. OS 37 98 31.57 38.64 32.15 39 33 82.77 68.9 SO 57 37 45 SI. 10 38 07 31.65 38 73 32.23 39 43 82.86 69.0 SO. 6 ft 37 53 31.17 38.15 31.72 38 82 32.31 39 52 32.94 SO. 71 37 61 31.25 38 24 31.79 38 90 32.39 39 61 38.02 69^2 SO. 78 37 69 31.32 38 32 31.87 38 99 32.47 39 70 33.10 69.3 SO. 85 37.78 31.39 38.41 31.94 39 08 32.55 39.80 83.18 69.4 SO. 92 37 86 31.46 38 50 32.02 39 17 82.63 39 89 33.26 69.5 SO . 99 37 94 31.54 38 58 32.09 39 26 82.71 39 98 33.34 69.6 SI .06 38 03 31.61 38 67 32.17 39 35 82.78 40.07 33.43 69.7 SI IS 38.11 31.68 38 75 32.25 39.46 82.86 40.17 88.51 69.8 SI. 20 38 19 31.75 38.84 32.33 39.64 82.95 40.26 88.59 69.9 SI. 27 38 28 31.83 38.92 32.41 39 63 88.02 40 35 83.67 70.0 SI. 35 38 36 31.90 39 01 32.49 39 72 88.11 40 44 83.75 70.1 SI. 42 38 45 31.97 39 10 32.57 39 81 88.19 40 53 38.84 70.2 SI. 49 38 53 32.05 39 19 32.65 39 90 33.27 40 62 88.92 70.3 SI. 56 38 61 32.12 39 28 32.72 39.99 38.85 40.72 34.00 70.4 SI. 63 38 70 32.20 39 37 32.80 40 08 83.43 40.81 84.08 70.5 SI. 70 38 78 32.28 39.46 32.88 40.17 S8.51 40 90 84.17 70.6 SI. 78 38 87 32.36 39 55 32.96 40.26 33.59 40.99 84.25 70.7 SI. 85 38 95 32.43 39.64 33.04 40 35 38.68 41 08 34.83 70.8 SI. 92 39 04 32.51 39 73 33.12 40.45 33.76 41.18 84. 4^ 70.9 SI. 99 39 12 32.59 39 82 33.20 40.54 33.84 41.27 84.50 71.0 S2.07 39 21 32.67 39.91 33.28 40 63 33.92 41 36 84.58 71.1 S2.15 39 30 32.74 40.00 33.36 40 72 34.00 41.46 34.67 71.2 S2.22 39 39 32.82 40.09 33.44 40 81 34.08 41.55 34.75 71.3 S2.S0 39 48 32.90 40.18 33.52 40.90 84.17 41.64 34.83 71.4 S2.37 39 57 32.98 40.27 33.60 40 99 84.25 41.74 34.92 71.5 S2.45 39 65 33.05 40 36 33.68 41 08 84.88 41.83 35.00 71.6 S2.53 39 74 33.13 40 45 33.76 41.18 34-41 41 93 35.08 71.7 S2.60 39 83 33.21 40.54 33.84 41.27 34.50 42 02 85.17 71.8 S2.68 39 92 33.29 40.63 33.92 41 36 84.68 42 11 35.85 71.9 S2.76 40.01 33.37 40.72 34.00 41.45 34.66 42.21 35.84 72.0 S2.83 40.10 33.45 40 81 34.08 41 55 34.74 42 30 85.42 72.1 S2.91 40 18 33.52 40 90 34.16 41 64 34.88 42.40 35.51 72.2 S2.98 40 27 33.60 40.99 34.24 41 73 84.91 42.49 85.59 72.3 SS.06 40 36 33.68 41 08 34.33 41 82 84.99 42.58 85.68 72.4 SS.14 40 45 33.76 41.17 34.41 41 92 85.08 42 68 85.76 72.5 SS.22 40 54 33.84 41.26 3449 42.01 35.16 42.77 35.85 72.6 SS.29 40 62 33.91 41.35 34.57 42.10 85.24 42 87 35.93 72.7 SS.S7 40.71 33.99 41.45 34.65 42.19 35.83 42.96 36.02 72.8 SS.45 40 80 34.07 41.54 34.73 42 29 85.41 43.06 36.10 72.9 232 6 METHODS OF ANALYSIS [Chap. Table 17.— Alcohoi; 17.5 °C. 18° C. 19° c. 20° C. 21-c. : SCALE READING Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent* by by by by by by by by by volume weight volume weight volume weight volume weight volume 73.0 37 91 31.51 38 21 31.77 38.84 32.33 39.50 32.92 40.18 73.1 37.98 31.58 38 29 31.84 38 92 32.40 39 59 32.99 40.27 73.2 38 06 31.65 38 37 31.90 39 00 32.48 39.67 33.07 40.36 73.3 38.14 31.71 38 45 31.97 39 08 32.55 39 76 33.15 40.44 73.4 38 22 31.78 38 53 32.04 39.17 32.62 39.84 33.22 40.53 73.5 38 30 31.85 38 61 32.12 39 25 32.70 39 93 33.30 40.62 73.6 38 38 31.92 38 69 32.19 39.34 32.77 40.02 33.37 40.70 73.7 38.46 31.99 38 77 32.26 39 42 32.85 40.10 33.45 40.79 73.8 38.64 32.06 38 85 32.34 39 50 32.92 40.19 33.53 40.88 73.9 38.62 32.13 38 93 32.41 39 59 32.99 40.28 33.60 40.97 74.0 38 70 32.20 39 01 32.48 39 67 33.07 40.36 33.68 41.05 74.1 38 78 32.27 39 09 32.55 39 76 33.15 40.45 33.76 41.14 74.2 38 86 32.35 39.18 32.63 39.84 33.22 40.53 33.83 41.23 74.3 38 94 32.42 39 26 32.70 39 92 33.30 40.62 33.91 41 32 74.4 39 02 32.^9 39 34 32.77 40 01 33.37 40.71 33.98 41.41 74.5 39.10 32.56 39 43 32.85 40 09 33.45 40.79 34.06 41 50 74.6 39 18 32.63 39 51 32.92 40 18 33.53 40.88 34.14 41.59 74.7 39 26 32.70 39.59 32.99 40.27 33.60 40.97 34.22 41.68 74.8 39 36 32.78 39.68 33.07 40 35 33.68 41.06 34.30 41.77 74.9 39 43 32.85 39.76 33.15 40.44 33.76 41.14 34.38 41.86 75.0 39 51 32.92 39 84 33.22 40 53 33.83 41 23 34.46 41 96 75.1 39.60 32.99 39 93 33.30 40.61 33.91 41.32 34.54 42 04 75.2 39 68 33.07 40 01 33.37 40 70 33.98 41.41 34. 61 42.13 75.3 39 76 33.15 40 09 33.45 40.78 34.06 41.60 34.69 42.22 75.4 39 84 33.22 40 18 33.53 40.87 34.14 41.58 34.77 42.31 75.5 39.93 33.30 40 27 33.60 40.96 34.22 41.67 34.85 42.40 75.6 40.01 33.37 40 35 33.68 41.04 34.30 41.76 34.93 42.49 75.7 40 09 33.45 40 44 33.76 41 13 34.38 41 86 35.01 42.68 75.8 40 18 33.53 40 53 33.83 41 22 34.45 41.94 35.09 42.67 75.9 40.27 33.60 40 61 33.91 41.31 34.53 42 03 35.17 42.76 76.0 40 35 33.68 40 70 33.98 41.40 34. 61 42.12 35.25 42.85 76.1 40.44 33.76 40.78 34. 06 41.48 34.68 42.21 35.33 42.96 76.2 40.53 33.83 40 87 34.14 41.57 34.77 42.30 35.41 43.04 76.3 40.61 33.91 40.96 34.22 41.66 34.84 42.39 35.50 43.13 76.4 40.70 33.98 41 04 34.29 41.75 34.92 42.48 35.58 43.22 76.5 40 78 34.06 41 13 34.37 41.83 35.00 42.57 35.66 43.32 76.6 40.87 34.14 41.22 34.45 41.92 35.08 42 66 35.74 43.41 76.7 40.96 34.22 41.30 34.53 42.01 35.16 42.75 35.82 43.60 76.8 41.04 34.29 41.39 34. 60 42.10 35.24 42.84 35.90 43.60 76.9 41.13 34.37 41.48 34.68 42.19 35.32 42.93 35.98 43.69 77.0 41.22 34.45 41. or? 34.76 42.28 35.40 43.02 36.07 43.79 77.1 41.31 34.52 41.65 34.84 42.37 35.48 43.11 36.15 43.88 77.2 41.39 34. 60 41.74 34.91 42.46 35.56 43.20 36.24 43.97 77.3 41.48 34.68 41.83 34.99 42.54 35.64 43 30 86.32 44.07 77.4 41.57 34.75 41.91 35.07 42.63 35.72 43.39 36.40 44.16 77.5 41.66 34.83 42.00 35.15 42.72 35.80 43.48 36.49 44.26 77.6 41.75 34.91 42.09 35.23 42.81 35.88 43.57 36.57 44.36 77.7 41.83 34.98 42.17 35.30 42,90 35.96 43.67 36.66 44.46 77.8 41.92 35.06 42.26 35.38 42.99 36.04 43.76 36.74 44.54 77.9 42.01 35.14 42.35 35.46 43.08 36.13 43.85 36.82 44.64 XVI] Table.— Continued. WINES 233 6 21»C. 22 C. 23 c. 24 c. 25 c. Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent Per cent SCALE READING by by by by by by by by by weight volume weight volume weight volume weight volume weight SS.52 40 88 34-15 41 63 34.81 42 38 35.49 43.16 36.18 73.0 S3. 60 40.97 34.2s 41.72 34.89 42.47 35.58 43 24 36.27 73.1 SS.68 41 06 34.31 41.81 34.98 42.56 35.66 43 33 36.35 73.2 SS.75 41.16 34.S9 41.90 35.06 42 66 35.74 43 43 36.43 73.3 SS.8S 41.24 34.47 41 99 35.14 42.75 35.88 43 52 36.52 73.4 SS.91 41 33 34.55 42.08 35.22 42.84 35.91 43 61 36.60 73.5 SS.98 41 42 34.63 42.17 35.31 42 93 35.99 43.70 36.68 73.6 S4.06 41.51 S4.71 42.27 35.39 43.03 36.08 43 80 36.77 73.7 S4-U 41.60 34.79 42.36 35.47 43 12 36.16 43 89 36.85 73.8 34.22 41.69 34.87 42 46 35.55 43 21 36.24 43 98 36.93 73.9 34.30 41 78 34.95 42.54 35.64 43 31 36.33 44 08 37.02 74.0 34.38 41 87 35. OS 42 63 35.72 43 40 36. 41 44 18 37.11 74.1 34.46 41 96 35.12 42.72 35.80 43 49 36.49 44.28 37.20 74.2 34.54 42 06 35.20 42.82 35.88 43 68 36.58 44 38 87.29 74.3 34.62 42 15 35.28 42.91 35.97 43 68 36.66 44,48 37.38 74.4 34.70 42.24 35.36 43.00 36.05 43 77 36.74 44.57 37.47 74.5 34.78 42 33 35.45 43.09 36.13 43.86 36.83 44.67 37.56 74.6 34.86 42.42 35.53 43 19 36.22 43.96 36.91 44.77 37.65 74.7 34.94 42.51 35.61 43.28 36.30 44.05 36.99 44.87 37.75 74.8 35.02 42.61 35.69 43 37 36. S9 44.15 37.08 44 97 37.84 74.9 35.10 42.70 35.78 43.46 36.47 44.26 37.17 45.07 37.93 75.0 35.18 42.79 35.86 43.56 36.55 44.34 37.26 45 18 38.02 75.1 35.26 42.88 35.95 43 65 36.64 44.44 37.35 45 29 38.12 75.2 35.34 42 97 36.03 43.74 36.72 44.63 37.44 46 39 38.21 75.3 35.4s 43.07 36.11 43.83 36.81 44.63 37.63 46.50 38.31 75.4 35.51 43.16 36.20 43.92 36.89 44.73 37.62 45.61 38.40 75.5 35.59 43.25 36.28 44.02 36.97 44.83 37.71 45.71 38.50 75.6 35.67 43 35 36.36 44.12 37.06 44.93 37.80 46.82 38.60 75.7 35.75 43.44 36. 45 44.21 37.15 46 03 37.89 46 92 38.69 75.8 35.84 43 53 36.53 44 31 37.24 45 13 37.98 46 02 38.79 75.9 35.92 43.63 36.62 44.41 37.33 45.24 38.08 46 12 38.88 76.0 36.00 43.72 36.70 44.60 37.42 45.34 38.17 46 23 38.98 76.1 36.08 43.81 36.79 44.60 37.50 45.44 38.27 46.34 39.08 76.2 86.17 43.91 36.87 44.70 37.59 45 66 38.36 46.45 39.18 76.3 S6.25 44.00 36.96 44.80 57.68 45.65 38.46 46 56 39.29 76.4 S6.34 44.10 37.04 44.89 37.77 45.76 38.55 46 67 89.89 76.5 S6.42 44.19 37.13 44.99 37.86 46 86 38.65 46.78 39.49 76.6 S6.51 44.29 37.22 45.09 37.95 45.96 38.74 46.89 39.59 76.7 36.59 44.38 37.30 46.19 38.04 46.07 38.84 47.00 39.69 76.8 S6.68 44.48 37.39 46 30 38.13 46.18 38.93 47.11 39.80 76.9 S6.76 44.57 37.47 45 40 38.23 46 29 39.03 47.23 39.90 77.0 36.85 44.67 37.56 46.50 38.32 46.40 39.13 47.34 40.00 77.1 36.93 44.76 37.65 45.60 38. 42 46.51 39.23 47 45 40.11 77.2 37.02 44.86 37.73 45.70 38.51 46.62 39.34 47.57 40.22 77.3 37.10 44.95 37.82 45.81 38.60 46.73 39.44 47.68 40.32 77.4 37.19 45.05 37.91 45.91 38.70 46 84 39.54 47.80 40.43 77.5 37.28 45.15 37.99 46.01 38.79 46 95 39.64 47.91 40.54 77.6 37. S6 45.25 38.08 46.12 38.89 47.06 39.74 48.02 40.65 77.7 37.45 45.35 38.18 46.23 38.98 47.17 39.85 48.14 40.75 77.8 S7.5S 45.45 38.27 46.34 39.08 47.28 39.95 48.26 40.86 77.9 234 6 METHODS OF ANALYSIS [Chap. Table 17.— Alcohoi 17.5 °c. 18 C. 19° C. 20° c. 21° C. READING Per cent by volume Per cent by weight Per cent by volume Per cent weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume 78.0 78.1 78.2 78.3 78.4 42.09 42.18 42.26 42 36 42.44 S5.22 35.30 35.38 35.45 35.53 42.43 42 52 42 61 42.70 42,78 35.54 35.62 35.70 35.77 35.85 43 17 43.27 43.36 43 45 43.54 36.21 36.29 36.38 36.46 36.54 43.94 44.04 44.13 44.23 44,32 36.91 36.99 37.08 37.16 37.25 44.73 44.83 44.92 46.02 45.12 78.5 78.6 78.7 78.8 78.9 42.52 42.61 42.69 42.78 42.86 35.61 35.69 35.77 35.84 35.92 42.87 42.96 43.05 43.14 43 23 35.93 36.01 36.09 36.17 36.26 43.63 43.72 43.82 43 91 44,00 36.63 36.71 36.79 36.88 36.96 44,42 44,51 44.60 44.70 44.79 37.33 37.42 37.50 37.59 37.68 46.22 46 32 46.42 46 62 45.62 79.0 79.1 79.2 79.3 79.4 42.95 43.04 43 13 43.22 43.31 36.00 36.08 36.16 36.25 36.33 43.32 43.41 43 50 43 59 43 68 36.34 36.42 36.50 36.59 36.67 44.09 44.19 44.28 44.38 44.47 37.04 37.13 37.21 37.30 37.38 44.89 44.98 45.08 45.18 45.28 37.76 37.85 37.94 38.02 38.11 46.72 46.82 45.92 46.02 46.13 79.5 79.6 79.7 79.8 79.9 43.40 43.49 43.58 43.67 43.76 36.41 36.49 36.57 36.66 36.74 43.77 43 86 43.95 44.06 44.14 36.75 36.83 36.92 37.00 37.09 44.56 44.65 44.75 44.84 44,93 37.47 37.56 37.64 37.73 37.81 45.38 45.48 45 58 46,68 46,78 38.20 38.30 38.39 38.48 38.57 46.24 46.34 46.46 46.56 46.67 80.0 43.85 36.82 44.24 37.17 45.04 37.90 45.88 38.67 46.77 XVIJ Table— Concluded . WINES 235 6 21° C. 22° C. 23° C. 24° C. 25° C. Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight Per cent by volume Per cent by weight SCALE READING S7.62 S7.71 S7.79 57.88 S7.97 S8.06 S8.15 S8.24 S8.33 S8.43 S8.52 S8.61 S8.70 S8.80 S8.89 S8.98 ' 59.08 \ S9.18 S9.28 1 59.38 59.48 i 45.56 38.37 45.66 38.46 45.76 38.56 45.86 38.65 46.96 38.75 46.07 38.84 46.17 38.93 46.28 39.03 46.39 39.13 46.60 39.23 46.61 39.33 46.72 39.43 46.83 39.54 46,93 39.64 47.04 39.74 47.15 39.84 47.26 39.94 47.37 40.04 47.48 40.14 47.59 40.:?4 47.70 40.35 46.45 39.18 46.56 39.29 46.67 39.39 46.78 39.49 46.89 39.59 47.00 39.69 47.11 39.80 47.22 39.90 47.34 40.00 47.45 40.// 47.56 40.21 47.67 40.S;2 47.79 40.4^ 47.90 40-53 48.01 40.63 48.12 40.74 48.23 40.84 48.34 40.95 48.46 41-05 48.57 4/./6 48.68 41-26 47.40 40-05 47.61 40.16 47.63 40.27 47.74 40.37 47.85 40-48 47.97 40.59 48.08 40.69 48.19 40.80 48.31 40.90 48.42 41.01 48.63 4/./^ 48.65 4/-?^ 48.76 41 -S3 48.88 4/. 44 48.99 41 -H 49.10 4/. 65 49.22 4/. 76 49.33 41.86 49.45 4^97 49.56 42.08 49.68 ig./S 48.37 40.97 48.49 41-08 48.60 41-18 48.72 4/. ^9 48.84 41-40 48.96 4/. 5/ 49,07 41-62 49,19 4/73 49.31 4/84 49.42 41-95 49.64 4:^.05 49.66 42.16 49.77 4:?.:87 49,89 4:2.38 60,01 42.49 50.13 4;g.60 50.24 4^.7/ 60.36 42.82 50.48 43.93 60.69 43.04 50.71 43/5 78.0 78.1 78.2 78.3 78.4 78.5 78.6 78.7 78.8 78.9 79.0 79.1 79.2 79.3 79.4 79.5 79.6 79.7 79.8 79.9 80.0 1 ! i • 236 METHODS OF ANALYSIS [Chap. GLYCEROL IN DRY WINES. 7 Method I. (By Direct Weighing) — Tentative. Evaporate 100 cc. of the wine in a porcelain dish on a water bath to a volume of about 10 cc. and treat the residue with about 5 grams of fine sand and 4-5 cc. of milk of lime (containing about 15% of calcium oxid) for each gram of extract pres- ent and evaporate almost to dryness. Treat the moist residue with 50 cc. of 90% alcohol by volume, remove the substance adhering to the sides of the dish with a spatula and rub the whole mass to a paste. Heat the mixture on a water bath, with constant stirring, to incipient boihng and decant the Uquid through a filter into a small flask. Wash the residue repeatedly by decantation with 10 cc. portions of hot 90% alcohol until the filtrate amounts to about 150 cc. Evaporate the filtrate to a sirupy consistency in a porcelain dish on a hot, but not boiling, water bath; transfer the residue to a small, glass-stoppered, graduated cylinder with 20 cc. of absolute alcohol and add 3 portions of 10 cc. each of anhydrous ether, shaking thoroughly after each addition. Let stand until clear, then pour off through a filter, and wash the cylinder and filter with a mixture of 1 part of absolute alcohol to 1| parts of anhydrous ether, also pouring the wash liquor through the filter. Evaporate the filtrate to a sirupy consistency, dry for an hour at the temperature of boiling water, weigh, ignite and weigh again. The loss on ignition gives the weight of glycerol. 8 Method II. (By Oxidation with Bichromate) — Tentative. Evaporate 100 cc. of the wine in a porcelain dish on a water bath, the temperature of which is maintained at 85°-90°C., to a volume of 10 cc. and treat the residue with about 5 grams of fine sand and 5 cc. of milk of lime (containing the equivalent of 15 grams of calcium oxid). Proceed from this point as directed under XIX, 6, be- ginning with the clause "evaporate almost to dryness, with frequent stirring". Observe the precautions given concerning the temperature at which all evapora- tions are to be made. 9 GLYCEROL IN SWEET WINES.— TENTATIVE. With wines whose extract exceeds 5 grams per 100 cc, heat 100 cc. to boiling in a flask and treat with successive small portions of milk of lime until the wine be- comes first darker and then lighter in color. Cool, add 200 cc. of 95% alcohol by volume, allow the precipitate to subside, filter and wash with 95% alcohol. Treat the combined filtrate and washings as directed in 7 or 8. 10 GLYCEROL-ALCOHOL RATIO.— TENTATIVE. Express this ratio as x : 100, in which x is obtained by multiplying the percentage by weight of glycerol by 100 and dividing the result by the percentage of alcohol by weight. EXTRACT. 11 From the Specific Gravity of the Dealcoholized Wine.— Tentatife. Calculate the specific gravity of the dealcoholized wine by the following formula: S = G-1-1 — Ain which S = specific gravity of the dealcoholized wine; G = specific gravity of the wine, 3; and A = specific gravity of the distillate obtained in the determination of alco- hol, 4 (a). XVI] WINES 237 From IX, 9, ascertain the per cent by weight of extract in the dealcoholized wine corresponding to the value of S. Multiply the figure thus obtained by the value of S to obtain the grams of extract per 100 cc. of wine. 12 By Evaporation.— Tentative. (a) In dry wines, having an extract content oj less than 3 grams per 100 cc. — Evapo- rate 50 cc. of the sample on a water bath to a sirupy consistency in a 75 cc. flat- bottomed platinum dish, approximately 85 mm. in diameter. Heat the residue for 2^ hours in a drying oven at the temperature of boiling water, cool in a desicca- tor and weigh as soon as the dish and contents reach room temperature. (b) In sweet xvines. — When the extract content is between 3 and 6 grams per 100 cc, treat 25 cc. of the sample as directed under (a). When the extract exceeds 6 grams per 100 cc, however, the result, obtained as directed under 11, is accepted and no gravimetric determination is attempted. This is because of the serious error connected with drying levulose at high tempera- ture. 13 NON-SUGAR SOLIDS.— TENTATIVE. Determine the non-sugar solids (sugar-free extract) by subtracting the amount of reducing sugars before inversion, 14, from the extract, 11 or 12. If sucrose is present in the wine, determine the non-sugar solids by subtracting the sum of re- ducing sugars before inversion and the sucrose from the extract. 14 REDUCING SUGARS.-TENTATIVE. (a) Dry wines. — Place 200 cc. of the wine in a porcelain dish, exactly neutralize with N/1 sodium hydroxid, calculating the amount required from the determina- tion of acidity, 25, and evaporate to about one fourth the original volume. Trans- fer to a 200 cc. flask, add sufficient neutral lead acetate solution to clarify, dilute to the mark with water, shake and filter through a folded filter. Remove the lead with dry potassium oxalate and determine reducing sugars as directed under VIII, 25. (b) Sweet wines. — In the case of sweet wines approximate the sugar content by subtracting 2 from the result in the determination of the extract and employ such a quantity of the sample that the aliquot taken for the copper reduction shall not exceed 245 mg. of invert sugar. Proceed as directed in (a) except that this smaller quantity of the sample is taken for the determination. SUCROSE. 15 By Reducing Sugars Before and After Inversion. — Tentative. Proceed as directed under VIII, 18, using the method given under VlJI, 25, for the determination of reducing sugars. 16 By Polarization. — Tentative. Polarize part of the filtrate, obtained in 14, before and after inversion in a 200 mm. tube as directed under VTII, 14 or 16. In calculating the percentage of sucrose the relation of the amount of sample contained in 100 cc. to the normal weight must be taken into consideration. 17 COMMERCIAL GLUCOSE.-TENTATIVE. Polarize a portion of the filtrate, obtained in 14, after inversion in a 200 mm. jacketed tube at 87°C. as directed "under IX, 25. In calculating the per- 238 METHODS OF ANALYSIS [Chap. centage of glucose the relation of the amount of sample contained in 100 cc. to the normal weight for the instrument must be taken into consideration. 18 ASH— TENTATIVE. Proceed as directed under VIII, 4, employing the residue from 50 cc. of the wine. "19 ASH-EXTRACT RATIO.— TENTATIVE. Express results as 1 : x, in which x is the quotient obtained by dividing the grams of extract per 100 cc. by the grams of ash per 100 cc. 20 ALKALINITY OF THE WATER-SOLUBLE ASH.— TENTATIVE. Extract the ash, obtained as directed under 18, with successive small portions of hot water until the filtrate amounts to about 60 cc. and proceed as directed under IX, 18. Express the alkalinity in terms of the number of cc. of N/10 acid required to neutralize the water-soluble ash from 100 cc. of the wine. 21 ALKALINITY OF THE WATER-INSOLUBLE ASH.— TENTATIVE. Ignite the filter and residue from 20 in the platinum dish in which the wine was ashed, and proceed as directed under DC, 19. Express the alkalinity in terms of the number of cc. of N/10 acid required to neutralize the water-insoluble ash from 100 cc. of the wine. 22 PHOSPHORIC ACID.— TENTATIVE. Dissolve the ash, obtained as directed under 18, in 50 cc. of boiling nitric acid (1 to 9), filter, wash the filter and determine phosphoric acid in the combined filtrate and washings, as directed in I, 6 or 9. If the ash ignites without difficulty, no free phosphoric acid need be suspected. Should there be any free acid, the ash remains black even after repeated leaching. In such cases calcimn acetate or a mixture containing 3 parts of sodium carbonate and 1 of sodivun nitrate should be added to avoid loss of phosphoric acid before attempting to ash. 23 SULPHURIC ACID.— TENTATIVE. Precipitate directly the sulphuric acid in 50 cc. of the wine by means of barium chlorid solution, after acidifying with a small excess of hydrochloric acid, and de- termine the resulting barium sulphate as directed under II, 20. Allow the precipi- tate to stand for at least 6 hours before filtering. Report as sulphur trioxid (SOj). 24 CHLORIN.-TENTATIVE. To 100 cc. of dry wine or 50 cc. of sweet wine add sufficient sodium carbonate to make distinctly alkaline. Evaporate to dryness, ignite at a heat not above low redness, cool, extract the residue with hot water, acidify the water extract with nitric acid and determine chlorin as directed under III, 15. 25 TOTAL ACIDS.— TENTATIVE. Measure 20 cc. of the wine into a 250 cc. beaker, heat rapidly to incipient boiling and immediately titrate with N/10 sodium hydroxid. Determine the end point with neutral 0.05% azolitmin solution as an outside indicator. Place the indicator in the cavities of a spot plate and spot the wine into the azolitmin solution. The end point is reached when the color of the indicator remains unchanged by the addition of a few drops of N/10 alkali to the wine. XVI] 239 In the case of wines which are artificially colored and which cannot be satis- factorily titrated in the above manner, it will be found helpful to use phenolphthalein powder (1 part of phenolphthalein mixed with 100 parts of dry, powdered potassium sulphate) as an indicator. Place this indicator in the cavities of a spot plate and spot the wine into the powder. The end of the titration is indicated when the pow- der acquires a pink tint. Express the result in terms of tartaric acid. One cc. of N/10 sodium hydroxid is equivalent to 0.0075 gram of tartaric acid. VOLATILE ACIDS, 26 Method I.— Tentative. Heat rapidly to incipient boiling 50 cc. of the wine in a 500 cc. distillation flask and pass steam through until 15 cc. of the distillate require only 2 drops of N/10 sodium hydroxid for neutralization. The water used to generate the steam should be boiled several minutes before connecting the steam generator with the distilla- tion flask in order to expel carbon dioxid. Titrate rapidly with N/10 sodium hy- droxid, using phenolphthalein as an indicator. The color should remain about 10 seconds. Express the result as acetic acid. One cc. of N/10 sodium hydroxid is equivalent to 0.0060 gram of acetic acid. 27 Method II. (Hortvet Method^)— Tentative. FIG. 8. APPAR.\TUS FOR THE DETERMIN.\TION OF VOLATILE ACIDS. Introduce 10 cc. of the wine, previously freed from carbon dioxid, into the inner tube of a modified Sellier distillation apparatus (Fig. 8), add a small piece of paraf- fin to prevent foaming, and adjust the tube and its contents in place within the larger flask containing 100 cc. of recently boiled water. Connect with a condenser as il- lustrated in Fig. 8 and distil by heating the outer flask. When 50 cc. of the distillate have been collected, emptj' the receiver into a beaker and titrate with N/10 sodium hydroxid, using phenolphthalein as an indicator. Continue the distillation and titrate each succeeding 10 cc. of distillate until not more than 1 drop of standard alkali is required to reach the neutral point. Usually 80 cc. of distillate will con- tain all the volatile acid. 240 METHODS OF ANALYSIS [Chap. 28 FIXED ACIDS.-TENTATIVE. Multiply the amount of volatile acids by 1.25 and subtract this from the total acids, to obtain the amount of fixed acids, expressed as tartaric acid. 29 TOTAL TARTARIC ACID'.— TENTATIVE. Neutralize 100 cc. of the wine with N/1 sodium hydroxid, calculating from the acidity, 25, the number of cc. of N/1 alkali necessary for the neutralization. If the volume of the solution is increased more than 10% by the addition of the alkali, evaporate to approximately 100 cc. Add to the neutralized solution 0.075 gram of tartaric acid for each cc. of N/1 alkali added and, after the tartaric acid has dis- solved, add 2 cc. of glacial acetic acid and 15 grams of potassium chlorid. After the potassium chlorid has dissolved, add 15 cc. of 95% alcohol by volume, stir vigorously until the potassium bitartrate starts to precipitate, and then let stand in an ice box for at least 15 hours. Decant the liquid from the separated potassium bitartrate on a Gooch, prepared with a very thin film of asbestos, or on filter paper in a Bijchner funnel. Wash the precipitate and filter 3 times with a few cc. of a mixture of 15 grams of potassium chlorid, 20 cc. of 95% alcohol by volume and 100 cc. of water, using not more than 20 cc. of the wash solution in all. Transfer the asbestos or paper and precipitate to the beaker in which the precipitation was made, wash out the Gooch or Buchner funnel with hot water, using about 50 cc. in all, heat to boiling and titrate the hot solution with N/10 sodium hydroxid, using phenolphthalein as an indicator. Increase the number of cc. of N/10 alkali re- quired by 1.5 cc. to allow for the solubility of the precipitate. One cc. of N/10 alkali is equivalent, under these conditions, to 0.015 gram of tartaric acid. Subtract the amount of tartaric acid added from this result to obtain the grams of total tartaric acid per 100 cc. of the wine. 30 FREE TARTARIC ACID AND CREAM OF TARTAR^.— TENTATIVE. Calculate the free tartaric acid and cream of tartar in the following manner: Let A = total tartaric acid in 100 cc. of wine divided by 0.015; B = total alkalinity of the ash (sum of C and D) ; C = alkalinity of water-soluble ash; D = alkalinity of water-insoluble ash. Then 31 (1) If A is greater than B, Cream of tartar = 0.0188 X C; and Free tartaric acid = 0.015 X (A-B). (2) If A equals B or is smaller than B but greater than C, Cream of tartar = 0.0188 X C; and Free tartaric acid = 0. (3) If A is smaller than C, Cream of tartar = 0.0188 X A; and Free tartaric acid = 0. TANNIN AND COLORING MATTER.-OFFICIAL. REAGENTS. (a) N/10 oxalic acid. — One cc. is equivalent to 0.004157 gram of tannin. *'• (b) Standard potassium permanganate solution. — Dissolve 1.333 grams of potas- sium permanganate in 1 liter of water and standardize the solution against (a). XVI] WINES 241 (C) Indigo solution. — Dissolve 6 grams of sodium sulphindigotate in 500 cc. of water by heating; cool, add 50 cc. of concentrated sulphuric acid, make up to 1 liter and filter. (d) Purified honehlac¥\—Bo\\ 100 grams of finely powdered boneblack with suc- cessive portions of hydrochloric acid (1 to 3), filter and wash with boiling water until free from chlorin. Keep covered with water. 32 DETERMINATION^. Dealcoholize 100 cc. of the wine by evaporation and dilute with water to the original volume. Transfer 10 cc. to a 2 liter porcelain dish; add about a liter of water and exactly 20 cc. of the indigo solution. Add the standard potassium permanganate solution, 1 cc. at a time, until the blue color changes to green; then add a few drops at a time until the color becomes golden yellow. Designate the number of cc. of permanganate solution used as "a". Treat 10 cc. of the dealcoholized wine, prepared as above, with boneblack for 15 minutes; filter and wash the boneblack thoroughly with water. Add a liter of water and 20 cc. of the indigo solution and titrate with permanganate as above. Designate the number of cc. of permanganate used as "b". Then a— b = c, the number of cc. of the permanganate solution required for the oxidation of the tannin and coloring matter in 10 cc. of the wine. 33 CRUDE PROTEIN.-TENTATIVE. Determine nitrogen in 50 cc. of the wine, as directed under I, 18, 21 or 23, and multiply the result by 6.25. 34 PENTOSANS.-TENTATIVE. Proceed as directed in VIII, 64, except that 100 cc. of the wine and 43 cc. of hy- drochloric acid (sp. gr. 1.19) are used in beginning the distillation. Owing to the interference of sugars this determination can be made in dry wines only. 35 GUM AND DEXTRIN.— TENTATIVE. Evaporate 100 cc. of the wine to about 10 cc. and add 10 cc. of 96% alcohol by volume. If gum or dextrin be present (indicated by the formation of a voluminous precipitate), continue the addition of alcohol, slowly and with stirring, until 100 cc. have been added. Let stand overnight, filter, and wash with 80% alcohol by volume. Dissolve the precipitate on the paper with hot water, hydrolyze the filtrate and washings with hydrochloric acid and proceed as directed under VIII, 60. 36 NITRATES.— TENTATIVE. (a) White vxine. — Treat a few drops of the wine in a porcelain dish with 2-3 cc. of concentrated sulphuric acid, which contains about 0.1 gram of diphenylamin* per 100 cc. The deep blue color formed in the presence of nitrates appears so quickly that it is not obscured, even in sweet wine, by the blackening produced by the ac- tion of sulphuric acid on the sugar. (b) Red vxine. — Clarify with basic lead acetate, filter, remove the excess of lead from the filtrate with sodium sulphate, filter again and treat a few drops of this filtrate as directed under (a). 37 COLORING MATTERS.-TENTATIVE. Proceed as directed under XI. 242 METHODS OF ANALYSIS 38 PRESERVATIVES.-TENTATIVE. Proceed as directed under X. The detection of added boric acid is somewhat difficult because a small amount of it is normally present in certain wines. Therefore, a quantitative determina- tion should be made. The determination of sulphurous acid must also be quanti- tative. A small amount of salicylic acid is also normal in wine, and for that reason not more than 50 cc. of the sample should be used in testing for that preservative. BIBLIOGRAPHY. ' U. S. Bur. Standards Bull. 9, No. 3. (Reprint 197). « J. Russ. Phys. Chem. Soc, 1908, 40: 107. ' J. Ind. Eng. Chem., 1909, 1: 31. * U. S. Bur. Chem. Bull. 162, p. 72. "* Ibid., p. 75. « U. S. P., VIII, 1907, p. 89. ' Ann. Oenologie, 1871-72, 2:1. "Arch. Hyg., 1884, 2: 273. XVII. DISTILLED LIQUORS. 1 SPECIFIC GRAVXTY.-TENTATIVE. Determine the specific gravity at -^ bj' means of a pycnometer or a small, accurately graduated hydrometer. 2 ALCOHOL BY WEIGHT.— OFFICIAL. Weigh 20-25 grams of the sample into a distillation flask, dilute with 100 cc. of water, distil nearly 100 cc. and weigh the distillate or make to volume at 20°C. and in either case, determine the specific gravity as directed under 1 . Obtain the corre- sponding percentage of alcohol by weight from XVI, 5, multiply this figure by the weight of the distillate, and divide by the weight of the sample taken to obtain the per cent of alcohol by weight. The alcohol content of the distillate may be checked by determining the immer- sion refractometer reading and obtaining, from XVI, 6, the percentage of alcohol. ALCOHOL BY VOLUME. 3 Method I.— Official. From the specific gravity of the distillate, obtained under 2, ascertain the cor- responding percentage of alcohol by volume from XVI, 5. Multiply this figure by the volume of distillate and divide by the volume of the sample (calculated from the specific gravity) to obtain the percentage of alcohol by volume in the original sample. 4 Method II.— Tentative. Measure 25 cc. of the sample at 20°C. into a distillation flask, dilute with 100 cc. of water, distil nearly 100 cc, make to volume at 20°C. and determine the spe- cific gravity as directed in 1 . Obtain, from XVI, 5, the corresponding percentage of alcohol by volume in the distillate. Multiply by 4 to obtain the percentage of alcohol by volume in the original substance. The alcohol content of the distillate may be checked by determining the immer- sion refractometer reading and obtaining the percentage of alcohol from XVI, 6. 5 EXTRACT.— OFFICIAL. Weigh, or measure at 20°C., 100 cc. of the sample, evaporate nearh' to dryness on the water bath, then transfer to a water oven, and dry at the temperature of boiling water for 2^ hours. 6 ASH.-OFFICLAL. Proceed as directed under VIII, 4, employing the residue from the determination of the extract, 5. 7 ACIDITY.-TENTATIVE. Titrate 100 cc. of the sample (or 50 cc. diluted to 100 cc. if the sample is dark) with N/10 alkali, using phenolphthalein as an indicator. Express the result as acetic acid; 1 cc. of N/10 alkali is equivalent to 0.0060 gram of acetic acid. 243 244 METHODS OF ANALYSIS [Chap. 8 ESTERS.-TENTATIVE. Measure 200 cc. of the sample into a distillation flask, add 25 cc. of water and distil slowly 200 cc, using a mercury valve to prevent loss of alcohol. Exactly neutralize the free acid in 50 cc. of the distillate with N/10 alkali, add a measured excess of 25-50 cc. of N/10 alkali, and either boil for an hour under a reflux con- denser, cool and titrate with N/10 acid, or allow the solution to stand overnight in a stoppered flask with the excess of alkali, heat with a tube condenser for 30 min- utes at a temperature below the boiling point, cool and titrate. Calculate the number of cc. of N/10 alkali used in the saponification of the esters as ethyl acetate; 1 cc. of N/10 alkali is equivalent to 0.0088 gram of ethyl acetate. Run a blank using water in place of the distillate and make any necessary correction. ALDEHYDES— TENTATIVE. 9 KBAGENTS. (a) Aldehyde-free alcohol. — Redistil 95% alcohol over sodium or potassium hy- droxid, then add 2-3 grams per liter of meta-phenylendiamin hydrochlorid, digest at ordinary temperature for several days (or reflux on a steam bath for several hours) and then distil slowly, rejecting the first 100 cc. and the last 200 cc. of the distillate. (b) Sulphite-fuchsin solution. — Dissolve 0.50 gram of pure fuchsin in 500 cc. of water, then add 5 grams of sulphur dioxid dissolved in water, make up to 1 liter and allow to stand until colorless. This solution does not keep indefinitely; there- fore, prepare in small quantities and keep at a low temperature. (C) Standard acetaldehyde solution. — Prepare according to the directions of Vasey^ as follows : Grind aldehyde ammonia in a mortar with anhydrous ether and decant the ether. Repeat this operation several times, then dry the purified salt in a current of air and finally in vacuo over sulphuric acid. Dissolve 1.386 grams of this purified aldehyde ammonia in 50 cc. of 95% alcohol by volume, add 22.7 cc. of N/1 alcoholic sulphuric acid, then make up to 100 cc. and add 0.8 cc. of alcohol for the volume of the ammonium sulphate precipitate. Allow the mixture to stand overnight and filter. This solution contains 1 gram of acetaldehyde in 100 cc. and will retain its strength. The standard found most convenient for use is 2 cc. of this strong aldehyde solution diluted to 100 cc. with 50% alcohol by volume. One cc. of this solution is equivalent to 0.0002 gram of acetaldehyde. This solution should be made up fresh every day or so, as it loses strength. 10 DETERMINATION. Determine the aldehyde in the distillate, prepared as directed under 8. Dilute 5-10 cc. of the distillate to 50 cc. with aldehyde-free alcohol 50% by volume, add 25 cc. of the sulphite-fuchsin solution and allow to stand for 15 minutes at 15°C. The solutions and reagents should be at 15°C. when they are mixed. Prepare standards of known strength and blanks in the same way. The comparison standards found most convenient for use contain 0.0001, 0.0002, 0.0004, 0.0005 and 0.0006 gram of acetaldehyde. FURFURAL.— TENTATIVE. 11 REAGENTS. (a) Standard furfural solution. — Dissolve 1 gram of redistilled furfural in 100 cc. of 95% alcohol by volume. Standards are made by diluting 1 cc. of this solu- XVII] DISTILLED LIQUORS 245 tion to 100 cc. with 50% alcohol b}' volume. One cc. of this solution contains 0.0001 gram of furfural. (b) Furfural-free alcohol. — Prepare as directed in 9 (a). 1 2 DETERMINATION. Dilute 10-20 cc. of the distillate, as prepared under 8, to 50 cc. with furfural- free alcohol, 50% by volume. Add 2 cc. of colorless anilin and 0.5 cc. of hydro- chloric acid (sp. gr. 1.125) and keep for 15 minutes in a water bath at about 15°C. Prepare standards of known strength and blanks in the same way. The compari- son standards found most convenient for use contain 0.00005, 0.0001, 0.00015, 0.0002, 0.00025 and 0.0003 gram of furfural. FUSEL OIL.-TENTATIVE. 13 REAGENTS. (a) Purified carbon tetrachlorid. — Mix crude carbon tetrachlorid with one tenth its volume of concentrated sulphuric acid, shake thoroughly at frequent intervals and allow to stand overnight. Wash free of acid and impurities with tap water. Remove the water, add an excess of sodium hydroxid solution and distil the carbon tetrachlorid from it. (b) Oxidizing solution. — Disssolve 100 grams of potassium dichromate in 900 cc. of water and add 100 cc. of concentrated sulphuric acid. 14 DETERMINATION. (1) To 100 cc. of the sample add 20 cc. of N/2 sodium hydroxid and saponify the mixture by boiling for an hour under a reflux condenser; or, (2) Mix 100 cc. of the liquor with 20 cc. of N/2 sodium hydroxid, allow to stand overnight at room tem- perature and distil directly. Connect the flask with a distillation apparatus, distil 90 cc, add 25 cc. of water and continue the distillation until an additional 25 cc. are collected. Whenever aldehydes are present in excess of 15 parts per 100,000, add to the dis- tillate 0.5 gram of meta-phenylendiamin hydrochlorid, reflux for an hour, distil 100 cc, add 25 cc. of water and continue the distillation until an additional 25 cc. are collected. Approximately saturate the distillate with finely ground sodium chlorid and add saturated sodium chlorid solution until the specific gravity is 1.10. Extract this salt solution 4 times with the purified carbon tetrachlorid, using 40, 30, 20 and 10 cc, respectively, and wash the carbon tetrachlorid 3 times with 50 cc. portions of saturated sodium chlorid solution, and twice with saturated sodium sulphate solution. Then transfer the carbon tetrachlorid to a flask containing 50 cc. of the oxidizing solution and boil for 8 hours under a reflux condenser. Add 30 cc. of water and distil until only about 20 cc. remain; add 80 cc. of water and again distil until 15-20 cc. are left. Neutralize the distillate to methyl orange, and titrate with N/10 sodium hydroxid, using phenolphthalein as an indicator. If the distillations have been properly conducted, the distillate will not show a marked acid reaction to methyl orange. Should considerably more than 1 cc. of N/10 alkali be consumed at this point, the result will be unreliable and the deter- mination should be repeated. One cc. of N/10 sodium hydroxid is equivalent to 0.0088 gram of amyl alcohol. Rubber stoppers can be used in the saponification and first distillation, but corks covered with tinfoil must be used in the oxidation and second distillation. Corks and tinfoil must be renewed frequently. 246 METHODS OF ANALYSIS [Chap. Conduct a blank determination upon 100 cc. of carbon tetrachlorid beginning the blank at that point of the procedure immediately after the extraction and just before the washings with sodium chlorid and sodium sulphate solutions. 1 5 SUGARS.-TENTATIVE. Proceed as directed under XVI, 15, 16 or 17. METHYL ALCOHOL. 16 Trillal Method^.— Tentative. To 50 cc. of the sample add 50 cc. of water and 8 grams of lime and fractionate by the aid of Glinsky bulb tubes. Dilute the first 15 cc. of the distillate to 150 cc, mix with 15 grams of potassimn dichromate and 70 cc. of sulphuric acid (1 to 5), and allow to stand for an hour with occasional shaking. Distil, reject the first 25 cc. and collect 100 cc. Mix 50 cc. of the distillate with 1 cc. of redistilled dimethylanilin, transfer to a stout, tightly stoppered flask, and keep on a bath at 70°-80°C. for 3 hours with occasional shaking. Make distinctly alkaline with sodium hydroxid solution, and distil off the excess of dimethylanilin, stopping the distillation when 25 cc. have passed over. Acidify the residue in the flask with acetic acid, shake and test a few cc. by add- ing 4 or 5 drops of 1% suspension of lead dioxid. If methyl alcohol is present, a blue coloration occurs which is increased by boiling. Ethyl alcohol thus treated yields a blue coloration changing immediately to green, later to yellow, and becoming colorless when boiled. 1 7 Riche and Bardy Method^. — Tentative. The following method for the detection of methyl alcohol in commercial spirit of wine depends on the formation of methylanilin violet : Place 10 cc. of the sample, previously redistilled over potassium carbonate if necessary, in a small flask with 15 grams of iodin and 2 grams of red phosphorus. Keep in ice water for 10-15 minutes until action has ceased. Distil off, on a water bath, the methyl and ethyl iodids formed into about 30 cc. of water. Wash with dilute alkali to eliminate free iodin. Separate the heavy, oily liquid which settles and transfer to a flask containing 5 cc. of anilin. If the action be too violent, place the flask in cold water; if too slow, stimulate by gently warming the flask. After an hour boil the product with water and add about 20 cc. of 15% sodium hydroxid solution; when the bases rise to the top as an oily layer, fill the flask up to the neck with water and draw them off with a pipette. Oxidize 1 cc. of the oily liquid by adding 10 grams of a mixture of 100 parts of clean sand, 2 of common salt, and 3 of cupric nitrate; mix thoroughly, transfer to a glass tube, and heat to 90°C. for 8-10 hours. Exhaust the product with warm alcohol, filter and make up to 100 cc. with alcohol. If the sample of spirits is pure, the liquid has a red tint, but, in the presence of 1% of methyl alcohol, it has a distinct violet shade; with 2.5% the shade is very distinct, and still more so with 5%. To detect more minute quan- tities of methyl alcohol, dilute 5 cc. of the colored liquid to 100 cc. with water, and dilute 5 cc. of this again to 400 cc. Heat the liquid thus obtained in a porcelain dish and immerse in it a fragment of white merino (free from sulphur) for 30 min- utes. If the alcohol is pure, the wool will remain white, but, if methyl alcohol is present, the fiber will become violet, the depth of tint giving a fairly approximate indication of the proportion of methyl alcohol present. XVII] DISTILLED LIQUORS 247 18 Immersion Refractometer Method. (Leach and Lythgoe*) — Tentative. Determine by the immersion refractometer at 20°C. the refraction of the distil- late obtained in the determination of alcohol. If, on reference to the table under 19, the refraction shows the percentage of alcohol agreeing with that obtained from the specific gravity, it may safely be assumed that no methyl alcohol is present. If, however, there is an appreciable amount of methyl alcohol, the low refractome- ter reading will at once indicate the fact. If the absence from the solution of re- fractive substances other than water and the alcohols is assured, this difference in refraction is conclusive of the presence of methyl alcohol. The addition of methyl alcohol to ethyl alcohol decreases the refraction in direct proportion to the amount present; hence the quantitative calculation is readily made by interpolation in the table under 19, using the figures for pure ethyl and methyl alcohol of the same alcoholic strength as the sample. Example. — The distillate has a specific gravity of 0.97080, corresponding to 18.38% alcohol by weight, and has a refraction of 35.8 at 20°C. by the immersion refractometer; by interpolation in the refractometer table the readings of ethyl and methyl alcohol corresponding to 18.38% alcohol are 47.3 and 25.4, respectivelv, the difference being 21.9; 47.3 - 35.8 = 11.5; (11.5 -^ 21.9) 100 = 52.5, showing that 52.5% of the total alcohol present is methyl alcohol. 19 Table 18. Scale readings of the Zeiss immersion refractometer at 20°C., corresponding to each per cent hy weight of methyl and ethyl alcohols. PER SCAXE READINGS PER SCALE READINGS PER SCALE READINGS PER SCALE READINGS CENT CENT ALCO- CENT ALCO- CENT ALCO- ALCO- HOL Methyl Ethyl HOL Methyl Ethyl HOL Methyl Ethyl HOL Methyl Ethyl BT alco- alco- BY alco- alco- BY alco- alco- BY alco- alco- WEIGHT hol hol WEIGHT hol hol WEIGHT hol hol WEIGHT hol hol 0 14.5 14.5 25 29.7 60.1 50 39.8 90.3 75 29.7 101.0 1 14.8 16.0 26 30.3 61.9 51 39.7 91.1 76 29.0 101.0 2 15.4 17.6 27 30.9 63.7 52 39.6 91.8 77 28.3 100.9 3 16.0 19.1 28 31.6 65.5 53 39.6 92.4 78 27.6 100.9 4 16.6 20.7 29 32.2 67.2 54 39.5 93.0 79 26.8 100.8 5 17.2 22.3 30 32.8 69.0 55 39.4 93.6 80 26.0 100.7 6 17.8 24.1 31 33.5 70.4 56 39.2 94.1 81 25.1 100.6 7 18.4 25.9 32 34.1 71.7 57 39.0 94.7 82 24.3 100.5 8 19.0 27.8 33 34.7 73.1 58 38.6 95.2 83 23.6 100.4 9 19.6 29.6 34 35.2 74.4 59 3S.3 95.7 84 22.8 100.3 10 20.2 31.4 35 35.8 75.8 60 37.9 96.2 85 21.8 100.1 11 20.8 33.2 36 36.3 76.9 61 37.5 96.7 86 20.8 99.8 12 21.4 35.0 37 36.8 78.0 62 37.0 97.1 87 19.7 99.5 13 22.0 36.9 38 37.3 79.1 63 36.5 97.5 88 18.6 99.2 14 22.6 38.7 39 37.7 80.2 64 36.0 98.0 89 17.3 98.9 15 23.2 40.5 40 38.1 81.3 65 35.5 98.3 90 16.1 98.6 16 23.9 42.5 41 38.4 82.3 66 35.0 98.7 91 14.9 98.3 17 24.5 44.5 42 38.8 83.3 67 34.5 99.1 92 13.7 97.8 18 25.2 46.5 43 39.2 84.2 68 34,0 99.4 93 12.4 97.2 19 25.8 48.5 44 39.3 85.2 69 33.5 99.7 94 11.0 96.4 20 26.5 50.5 45 39.4 86.2 70 33.0 100.0 95 9.6 95.7 21 27.1 52.4 46 39.5 87.0 71 32.3 100.2 96 8.2 94.9 22 27.8 54.3 47 39.6 87.8 72 31.7 100.4 97 6.7 94.0 23 28.4 56.3 48 39.7 88.7 73 31.1 100.6 98 3.5 93.0 24 29.1 58.2 49 39.8 89.5 74 30.4 100.8 99 100 3.5 2.0 92.0 91.0 248 METHODS OF ANALYSIS 20 COLORING MATTERS.-TENTATIVE.. Proceed as directed under XI. 21 WATER-INSOLUBLE COLOR IN WHISKIES.— TENTATIVE. Evaporate 50 cc. of the sample just to dryness on a steam bath. Take up with cold water, using approximately 15 cc, filter and wash until the filtrate amounts to nearly 25 cc. To this filtrate add 25 cc. of absolute alcohol, or 26.3 cc. of 95% alcohol by volume, and make up to 50 cc. by the addition of water. Mix thor- oughly and compare in a colorimeter with the original material. Calculate from these readings the per cent of color insoluble in water. COLORS INSOLUBLE IN AMYL ALCOHOL. 22 Modified Marsh Method.— Tentative. Evaporate 50 cc. of whisky just to dryness on a steam bath. Dissolve the residue in water and 95% alcohol by volume and make to a volume of 50 cc, using a total volume of 26.3 cc. of 95% alcohol. Place 25 cc. of this solution in a separatory funnel and add 20 cc. of freshly shaken Marsh reagent (100 cc. of pure amyl alco- hol, 3 cc. of sirupy phosphoric acid and 3 cc. of waterj, shaking lightly so as not to form an emulsion. Allow the layers to separate and repeat this shaking and stand- ing twice again. After the layers have separated completely draw off the lower or aqueous layer, which contains the caramel, into a 25 cc. cylinder and make up to volume with 50% alcohol by volume. Compare this solution in a colorimeter with the untreated 25 cc. Calculate the result of this reading to the per cent of color insoluble in amyl alcohol. CARAMEL. 23 Amthor Test Modified btj Lasche^. — Tentative. Add 10 cc. of paraldehyde to 5 cc. of the sample in a test tube and shake. Add absolute alcohol, a few drops at a time, shaking after each addition until the mixture becomes clear. Allow to stand. Turbidity after 10 minutes is an indication of caramel. BIBLIOGRAPHY. 1 Vasey. Guide to the Analysis of Potable Spirits. 1904, p. 31. 2 Abs. Analyst, 1899, 24: 13; Ibid., 211, 212. * Allen. Commercial Organic Analysis. 4th ed., 1909-14, 1: 98. *J. Am. Chem. Soc, 1905, 27: 9M. 6 The Brewer Distiller, May, 1903. XVin. BEERS. 1 PREPARATION OF SAMPLE.— TENTATIVE. Remove carbon dioxid by transferring the contents of the bottle to a large flask and shaking vigorously or by pouring back and forth between beakers, care being taken that the temperature of the beer is not below 20°C. 2 COLOR.— TENTATIVE. Determine the depth of color of the sample in a j inch cell with a Lovibond tin- tometer, using the beer scale. Express the result in terms of a i inch cell. 3 SPECIFIC GRAVITY.— TENTATIVE. Determine the specific gravity at —^-^ b}' means of a pycnometer. 4 ALCOHOL.— TENTATIVE. Determine as directed under XVI, 4. EXTRACT. 5 Method I.— Official. Measure 25 cc. of the carbon dioxid-free beer at 20°C. into a tared, flat-bottomed platinum dish, approximately 85 mm. in diameter, and evaporate just to dryness on a steam bath and heat to constant weight in a vacuum oven at 70°C. 6 Method 11.— Tentative. The immersion refractometer reading of the beer at 20°C. minus the immersion refractometer reading of the distillate at 20°C. times 0.2571 equals the grams of extract in 100 cc. of beer. 7 Method III.— Tentative. Calculate the specific gravity of the dealcoholized beer by the following formula: S = G4- 1- A in which S = the specific gravity of the dealcoholized beer; G = the specific gravity of the beer; and A = the specific gravity of the distillate obtained in the determination of alcohol. From IX, 9, ascertain the per cent by weight of extract in the dealcoholized beer corresponding to the value of S. Multiply the figure thus obtained by S to ob- tain the grams of extract per 100 cc. of beer. 8 EXTRACT OF ORIGINAL WORT (APPROXIMATE) .—TENTATIVK. Calculate the grams of extract per 100 cc. in the original wort by the following formula: O = 2A+ E in which O = extract of the original wort; A = alcohol (grams per 100 cc); and E = extract of the dealcoholized beer (grams per 100 cc). 249 250 METHODS OF ANALYSIS [Chap. 9 DEGREE OF FERMENTATION.— TENTATIVE. Calculate the degree of fermentation by the following formula: ^ 100 X 2A O in which D = degree of fermentation ; A = alcohol (grams per 100 cc); and O = extract of original wort. 10 TOTAL ACIDS.— TENTATIVE. Proceed as directed under XVI, 25. Express the result as lactic acid, grams per 100 cc. One cc. of N/10 sodium hydroxid is equivalent to 0.0090 gram of lactic acid. 1 1 VOLATILE ACIDS.-TENTATIVE, Proceed as directed under XVI, 27. Express the result as acetic acid, grams per 100 cc. 12 REDUCING SUGARS.-TENTATIVE. Dilute 25 cc. of the carbon dioxid-free beer, measured at 20°C., with water to 100 cc. of the same temperature. Determine the reducing sugars in 25 cc. of this solution, as directed under VIII, 42. Express the result as grams of anhydrous maltose per 100 cc. of beer. 1 3 DEXTRIN.— TENTATIVE. To 50 cc. of the carbon dioxid-free beer measured at 20°C., add 15 cc. of hydro- chloric acid (sp. gr. 1.125), dilute to 200 cc, attach to a reflux condenser and keep in a boiling water bath for 2 hours. Cool, nearly neutralize with sodium hydroxid solution, complete to a volume of 250 cc, filter and determine dextrose as directed under VIII, 52 or 54. From the number of grams of dextrose per 100 cc. of beer, subtract 1.053 times the amount of maltose as found in 12 and multiply the re- mainder by 0.9 to obtain the number of grams of dextrin per 100 cc. of beer. 14 DIRECT POLARIZATION.— TENTATIVE. Read the polarization of the original sample in degrees Ventzke in a 200 mm. tube at 20°C. If the beer is turbid, clarify by shaking with alumina cream, filter and correct the reading for dilution. 1 5 GLYCEROL.-TENTATIVE. Proceed as directed under XVI, 8. 16 ASH.-OFFICIAL. Evaporate to dryness 25 cc. of the carbon dioxid-free sample, measured at 20°C., and proceed as directed under VIII, 4. 1 7 PHOSPHORIC ACID.-TENTATIVE. To 25 cc. of the carbon dioxid-free beer, measured at 20°C., add 20 cc. of 2% calcium acetate solution, evaporate to dryness and ignite at low redness to a white ash. Add 10-15 cc. of boiling nitric acid (1 to 9) and determine phosphoric acid (P2O5) as directed under I, 9. XVIII] BEERS 251 1 8 PROTEIN.-OFFICIAL. Measure, at 20°C., 25 cc. of the carbon dioxid-free beer into a Kjeldahl digestion flask, add a small amount of tannin to prcvcMit frothing, evaporate to dryness, de- termine nitrogen as directed under I, 18, 21 or 23, multiply the result by 6.25 and calculate the percentage of protein, 1 9 PRESERVATIVES.-TENTATIVE. Proceed as directed under X. 20 COLORING MATTERS.— TENTATIVE. Proceed as directed under XI. 21 METALS.-TENTATIVE. Proceed as directed under XII. XIX. VINEGARS. (Unless otherwise noted, express results as grams per 100 cc.) 1 PHYSICAL EXAMINATION.— TENTATIVE. Note the appearance, color, odor and taste. 2 PREPARATION OF SAMPLE.-TENTATIVE. If the sample is turbid, filter before proceeding with the analysis. 3 SPECIFIC GRAVITY.— TENTATIVE. Determine the specific gravity at '-^^ by means of a pycnometer. 4 ALCOHOL.-TENTATIVE. Measure 100 cc. of the sample into a roimd-bottomed, distillation flask. Make faintly alkaline with saturated sodium hydroxid solution, add a small piece of paraflBn, distil almost 50 cc, make up to 50 cc. at the temperature of the sample and determine the specific gravity at -ji— ' by means of a pycnometer. Obtain from XVI, 5, the per cent by volume, or grams per 100 cc, noting that the alcoholic strength of the distillate is twice that of the original vinegar. GLYCEROL.— TENTATIVE. 5 REAGENTS. (a) Strong -potassium dichromale solution. — Dissolve 74.56 grams of dry, recrystal- lized potassium dichromate in water, add 150 cc. of concentrated sulphuric acid, cool and make up to 1 liter at 20°C. One cc. of this solution is equivalent to 0.01 gram of glycerol. The high coefficient of expansion of this strong solution necessi- tates its preparation at exactly 20°C. and the measurement of any definite volume at the same temperature. If desired, the measurements may be made at room temperature by means of a weighing burette, the volume used in this case being ascertained by dividing the weight of the solution used by its specific gravity at 20 "C. 4° (b) Dilute potassium dichromate solution. — Measure 25 cc. of the strong potas- sium dichromate solution at exactly 20°C. into a 500 cc volumetric flask, dilute with water and make up to the mark at room temperature. Twenty cc. of this solution are equivalent to 1 cc. of (a). (C) Ferrous ammonium sulphate solution. — Dissolve 30 grams of crystallized fer- rous ammonium sulphate in water, add 50 cc. of concentrated sulphuric acid, cool and dilute at room temperature. One cc. of this solution is approximately equiva- lent to 1 cc of (b). Its value changes slightly from day to day and it must be standardized against (b) whenever used. (d) Potassiiwi ferricijanid indicator. — Dissolve 1 gram of crystallized potassium ferricyanid in 50 cc. of water. This solution must be freshly prepared. (e) Milk of lime. — Introduce 150 grams of calcium oxid, selected from clean, hard lumps, prepared preferably from marble, into a largo porcelain or iron dish, slake with water, cool and add suflicient water to make 1 liter. 253 254 METHODS OF ANALYSIS [Chap. (f) Silver carbonate. — Dissolve 0.1 gram of silver sulphate in about 50 cc. of water, add an excess of sodium carbonate solution, allow the precipitate to settle and wash with water several times by decantation until the washings are practically- neutral. This reagent must be freshly prepared immediately before use. 6 DETERMINATION. All evaporations should be made on a ivaler bath, the temperature of which is main- tained at 85°-90°C. Evaporate 100 cc. of the vinegar to 5 cc, add 20 cc. of water and agarn evaporate to 5 cc. to expel acetic acid. Treat the residue with about 5 grams of fine sand and 15 cc. of the milk of lime and evaporate almost to dryness, with frequent stirring, avoiding the formation of a dry crust or evaporation to complete dryness. Treat the moist residue with 5 cc. of water, rub into a homogeneous paste, then add slowly 45 cc. of absolute alcohol, washing down the sides of the dish to remove adhering paste, and stir thoroughly. Heat the mixture on a water bath, with constant stirring, to incipient boiling, transfer to a suitable vessel and centrifu- galize. Decant the clear liquid into a porcelain dish and wash the residue with several small portions of hot 90% alcohol by volume by aid of the centrifuge. (If a centrifuge is not available, decant the liquid through a fluted filter into a porcelain dish. Wash the residue repeatedly with small portions of hot 90% alco- hol, twice by decantation, and then by transferring all the material to the filter. Continue the washing until the filtrate amounts to 150 cc.) Evaporate to a sirupy consistency, add 10 cc. of absolute alcohol to dissolve this residue and transfer to a 50 cc. glass-stoppered cylinder, washing the dish with successive small portions of absolute alcohol until the volume of the solution amounts to 20 cc. Then add 3 portions of 10 cc. each of anhydrous ether, shaking thoroughly after each addi- tion. Let stand until clear, then pour off through a filter, and wash the cylinder and filter with a mixture of 2 volumes of absolute alcohol and 3 of anhydrous ether. If a heavy precipitate has formed in the cylinder, centrifugalize at low speed, de- cant the clear liquid and wash 3 times with 20 cc. portions of the alcohol-ether mixture, shaking the mixture thoroughly each time and separating the precipitate by means of the centrifuge. Wash the paper with the alcohol-ether mixture, and evaporate the filtrate and washings on the water bath to about 5 cc, add 20 cc. of water and again evaporate to 5 cc. ; again add 20 cc of water and evaporate to 5 CO.; finally add 10 cc. of water and evaporate to 5 cc. These evaporations are necessary to remove all the ether and alcohol, and, when conducted at 85°-90°C., result in no loss of glycerol if the concentration of the latter is less than 50%. Transfer the residue with hot water to a 50 cc. graduated flask, cool, add the silver carbonate, prepared from 0.1 gram of silver sulphate, shake and allow to stand 10 minutes; then add 0.5 cc. of basic lead acetate solution [VIII, 13 (a)], shake occasionally and allow to stand 10 minutes; make up to the mark, shake well, filter, rejecting the first portion of the filtrate, and pipette 25 cc. of the clear filtrate into a 250 cc. volumetric flask. Add 1 cc. of concentrated sulphuric acid to precipitate the excess of lead and then 30 cc. of the strong potassium dichromate solution. Add carefully 24 cc. of concentrated sulphuric acid, rotating the flask gently to mix the contents and avoid violent ebullition, and then place in a boiling water bath for exactly 20 minutes. Remove the flask from the bath, dilute, cool and make up to the mark at room tem- perature. The amount of strong dichromate solution used must be sufficient to XIX] VINEGARS 255 leave an excess of about 12.5 cc. at the end of the oxidation, the amount given above (30 cc.) being sufficient for ordinary vinegar containing about 0.35 gram or less of glycerol per 100 cc. Standardize the ferrous ammonium sulphate solution against the dilute potas- sium dichromate solution by introducing from the respective burettes approxi- mately 20 cc. of each of the 2 solutions into a beaker containing 100 cc. of water. Complete the titration using the potassium ferricyanid solution as an outside indi- cator. From this titration calculate the volume {F) of the ferrous ammonium sul- phate solution equivalent to 20 cc. of the dilute and also, therefore, to 1 cc. of the strong dichromate solution. In place of the dilute dichromate solution, substitute a burette containing the oxidized glycerol with an excess of the strong dichromate solution and ascertain how many cc. are equivalent to (F) cc. of the ferrous ammonium sulphate solution and also, therefore, to 1 cc. of the strong dichromate solution. Then 250 divided by this last equivalent equals the number of cc. of the strong dichromate solution pres- ent in excess in the 250 cc. flask after oxidation of the glycerol. The number of cc. of the strong dichromate solution added, minus the excess found after oxidation, multiplied by 0.02 gives the grams of glycerol per 100 cc. of vinegar. 7 SOLIDS.-TENTATIVE. Measure 10 cc. of the sample into a tared, fiat-bottomed platinum dish of 50 mm. bottom diameter, evaporate on a boiling water bath for 30 minutes, and dry for exactly 2k hours in a water oven at the temperature of boiling water. Cool in a desiccator and weigh. It is essential that the size and shape of the dish and the time of drying be followed strictly. 8 TOTAL REDUCING SUBSTANCES BEFORE INVERSION.— TENTATIVE. Proceed as directed under VIII, 25, using 10 cc. of the sample. In the case of malt vinegar, express the results as dextrose; in all other cases as invert sugar. 9 REDUCING SUGARS BEFORE INVERSION AFTER EVAPORATION.— TENTATIVE. Evaporate 50 cc. of the sample on the water bath to a volume of 5 cc. Add 25 cc. of water and again evaporate to 5 cc. Transfer to a 100 cc. volumetric flask, make up to the mark, and proceed as directed under 8, using a quantity equivalent to 10 or 20 cc. of the sample. 1 0 REDUCING SUGARS AFTER INVERSION.-TENTATIVE. Proceed as directed under 9. After the last evaporation to 5 cc. transfer to a 100 cc. volumetric flask with 70 cc. of water, and invert as directed under VIII, 14. Nearly neutralize with sodium hydroxid solution, make up to the mark and proceed as directed under VIII, 25, using a quantity equivalent to 10 or 20 cc. of the sample. 11 LEAD PRECIPITATE.-TENTATIVE. To 10 CC. of the sample in a test tube, add 2 cc. of 20% lead acetate solution, shake and let stand 30 minutes. Describe the precipitate as turbid, light, normal, heavy or very heavy. 12 . POLARIZATION.-TENTATIVE. If the lead precipitate is normal, add to 50 cc. of the sample 5 cc. of basic lead acetate solution [VIII, 13 (a)], shake, let stand 30 minutes, filter and polarize, 256 METHODS OF ANALYSIS [Chap. preferably in a 200 mm. tube, correcting for dilution. If basic lead acetate gives only a turbidity, add to the sample, already treated with basic lead acetate, 10 cc. of alumina cream [VIII, 13 (b)], shake, let stand 30 minutes, filter and polarize, correcting for dilution. In the case of malt vinegar, treat 100 cc. of the sample with 6 cc. of 10% phosphotungstic acid solution and filter. To 50 cc. of the filtrate add 5 cc. of the basic lead acetate solution, filter and polarize, correcting the reading obtained for dilution. 1 3 ASH.-TENTATIVE. (a) Measure 25 cc. of the vinegar into a tared platinum dish, evaporate to dry- ness on the steam bath and proceed as directed under VIII, 4. (b) Evaporate 25 cc. of the sample to dryness as directed under (a), heat in a mufiJe at low heat to expel inflammable gases, treat the charred portion with a few cc. of water, and evaporate to dryness on a water bath; replace in the muffle at low redness for 15 minutes, and continue the alternate evaporation and heating until a white or gray ash is obtained, at no time exceeding a dull red heat; cool in a de.siccator and weigh. Useful information may often be obtained by noting the odor given off by the solids during charring. 14 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE. Treat the ash, obtained in 13, as directed under IX, 17. 1 5 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE. Proceed as directed under IX, 18, expressing the result as the number of cc. of N/10 hydrochloric acid required to neutralize the soluble ash from 100 cc. of the vinegar. 1 3 SOLUBLE AND INSOLUBLE PHOSPHORIC ACID.— TENTATIVE. Determine phosphoric acid in the water-soluble and water-insoluble portions of the ash as directed under I, 9, dissolving the water-insoluble portion in about 50 cc. of boiling nitric acid (1 to 9). Express the result as mg. of phosphorus pentoxid (P2O6) in 100 cc. of the vinegar. 1 7 TOTAL ACIDS.-TENTATIVE. Dilute 10 cc. of the sample with recently boiled and cooled water until it appears very slightly colored, and titrate with N/2 alkali, using phenolphthalein as an indicator. One cc. of N/2 alkali is equivalent to 0.030 gram of acetic acid. 1 8 FIXED ACIDS.-TENTATIVE. Measure 10 cc. of the vinegar into a 200 cc. porcelain casserole, evaporate just to dryness, add 5-10 cc. of water, and again evaporate; repeat until at least 5 evapora- tions have taken place. Add about 200 cc. of recently boiled and cooled water and titrate with N/10 alkali, using phenolphthalein as an indicator. One cc. of N/10 alkali is equivalent to 0.0067 gram of malic acid. 19 VOLATILE ACIDS.-TENTATIVE. To obtain the volatile acids subtract the fixed acids, calculated as acetic acid, from the total acids. XIX] VINEGARS 257 20 COLOR.-TENTATIVE. Determine the depth of color in a Lovibond tintometer by good, reflected day- light, using a ^ inch cell and the brewer's scale. Express the result in terms of a -^ inch cell. FORMIC ACID. 21 Fincke Method}. — Tentative. Employ the apparatus described under X, 39, Fig. 6. Introduce 100 cc. of the sample into flask {A), add 0.4-0.5 gram of tartaric acid, and place in position as shown in Fig. 6, the flask (JB) having previously been charged with a suspension of 15 grams of calcium carbonate in 100 cc. of water. Heat the contents of flasks (A) and {B) to boiling and distil with steam from the generator (5), the vapor passing first through the sample in flask {A), then through the boiling suspension of cal- cium carbonate in flask {B), after which it is condensed and measured in the re- ceiver (C). Maintain the volume of liquid in flask {B) as nearly constant as pos- sible and reduce the volume of the sample in flask (A) to 30-40 cc. by heating with small Bunsen flames, the distillation being continued until 1 liter of distillate is collected. Disconnect the apparatus, filter the calcium carbonate suspension, and wash the calcium carbonate that remains on the paper with a little hot water. Render the filtrate faintly acid with hydrochloric acid, add 10-15 cc. of mercuric chlorid reagent [ X, 38 (b) ], mix and heat on a boiling water bath for 2 hours. Filter on a tared Gooch, wash the precipitate thoroughly with cold water and finally with a little alcohol. Dry in a boiling water oven for 30 minutes, cool in a desiccator, weigh, and calculate the weight of formic acid present by multiplying the weight of the precipitate by 0.0975. 22 ALCOHOL PRECIPITATE.— TENTATIVE. Evaporate 100 cc. of the vinegar to about 15 cc. When there is considerable sugar in the vinegar, if the sample is evaporated to too low a volume, a gummy or stringy precipitate is formed on adding the,alcohol instead of a flocculent one. When the sugar content is high, therefore, the evaporation should not be carried beyond 20 cc. To this residue add slowly and with constant stirring 200 cc. of 95% alcohol by volume and allow the mixture to stand overnight. From this point proceed as directed under XIII, 18, beginning with the sentence, "Filter and wash with 80% alcohol by volume". 23 PENTOSANS.-TENTATIVE. Proceed as directed in VIII, 84, except that 100 cc. of the vinegar and 43 cc. of hydrochloric acid (sp. gr. 1.19) are used in beginning the distillation. TARTARIC ACID AND TARTRATES. 24 Qualitative Test.— Tentative. Evaporate 50 cc. of the vinegar in a porcelain dish to a volume of about 10 cc, filter into a test tube, add 1 cc. of 25% calcium chlorid solution and 2 cc. of 50% ammonium acetate solution and allow to stand overnight. In the presence of tar- taric acid a deposit of calcium tartrate is formed, the crystals of which may be identified under the microscope by their characteristic form. 25 TOTAL TARTARIC ACID.-TENTATIVE. Evaporate 200 cc. of the sample to a sirupy consistency to remove excess of acetic acid, dilute to the original volume with water in a volumetric flask, determine the 258 METHODS OF ANALYSIS acidity as directed in 17, and determine total tartaric acid in a 100 cc. aliquot as directed under XVI, 29, except that 20 cc. of alcohol are used in the precipitation instead of 15 cc. FREE MINERAL ACIDS. 26 Logivood Method'^. — Tentative. Prepare an extract of logwood as follows: Pour 100 cc. of boiling water upon 2 grams of fresh logwood chips, allow the infusion to stand for a few hours and filter. Place drops of the liquid on a porcelain surface and dry on a water bath. Add to one of the spots a drop of the vinegar to be tested (after concentration if desirable) and evaporate to dryness. A yellow tint remains if free mineral acids are absent, a red tint if they are present. 27 Methyl Violet Method. — Tentative. Add 5-10 cc. of water to 5 cc. of vinegar and, after mixing well, add 4 or 5 drops of methyl violet solution (1 part of methyl violet 2B in 10,000 parts of water). A blue or green coloration indicates the presence of a free mineral acid. 28 Quantitative Method. (Hehner Method) — Tentative. To a measured amount of the sample add a measured excess of standard alkali, evaporate to dryness, incinerate and titrate the ash with standard acid, using methyl orange as an indicator. The difference between the number of cc. of alkali first added and the number of cc. of acid needed to titrate the ash represents the free mineral acid present. 29 METALS.— TENTATIVE. Proceed as directed under XII. 30 Qualitative Test. — Tentative. Evaporate 100 cc. of the vinegar to a volume of about 15 cc. Add slowly and with constant stirring 200 cc. of 95% alcohol by volume and allow to stand over- night. The precipitate formed should be tested for dextrin by the optical rotation and color reaction with iodin. SPICES AND ADDED PUNGENT MATERIALS. 31 Qualitative Test. — Tentative. Neutralize exactly a portion of the vinegar and test by taste and smell. Agitate the liquid with ether in a separatory funnel, remove and evaporate the ethereal layer, and note the odor and taste of the residue. 32 COLORING MATTERS.— TENTATIVE. Proceed as directed under XI. • 33 PRESERVATIVES.— TENTATIVE, Proceed as directed under X. BIBLIOGRAPHY. 1 Z. Nahr. Genussm., 1911, 21: 1; 22: 88. 2 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 1: 503. XX. FLAVORING EXTRACTS. VANILLA EXTRACT AND ITS SUBSTITUTES. 1 SPECIFIC GRAVITY.-TENTATIVE. 20°C Determine the specific gravity at -p— ' by means of a pycnometer 2 ALCOHOL.-OFFICIAL. Proceed as directed under XVII, 2 or 3. 3 GLYCEROL.— TENTATIVE. Proceed as directed under XVI, 7, 8 or 9, the method selected depending upon the amount of sugar present, employing an amount of the sample containing 0.10- 0.40 gram of glycerol. VANltLlN AND COUMARIN. Modified Hess and Prescott Method^. — Tentative. (This method is not applicable to concentrated vanillin and coumarin preparations in which the amount of vanillin and coumarin present exceeds the quantity dissolved by 100 cc. of water at 20°C. In such cases employ a smaller amount of the sample and dilute to 50 cc.) 4 PREPARATION OF SOLUTION. Measure 50 cc. of the extract at 20°C. into a 250 cc. beaker with marks showing volumes of 80 and 50 cc, dilute to 80 cc. and evaporate to 50 cc. on a water bath kept at TO^C. Dilute again with water to 80 cc. and evaporate to 50 cc. Transfer to a 100 cc. flask, rinsing the beaker with hot water; add 25 cc. of 8% lead acetate solu- tion; make up to the mark with water, shake and allow to stand 18 hours (over- night) at 37°-40°C. Decant into a small, dry filter, reserving the filtrate for the determination of vanillin and coumarin, the normal lead number, 6, and the residual color, 14. 5 DETERMINATION. Transfer a 50 cc. aliquot of the filtrate to a separatory funnel and extract with 4 successive 15 cc. portions of ether (previously washed twice with an equal volume of water to remove alcohol). Wash the combined ether solutions 4 or 5 times with 2% ammonium hydroxid solution (2% NH3 by weight), using 10 cc. the first time and 5 cc. thereafter, and reserve the ether solution for the determination of cou- marin. Slightly acidify the combined ammoniacal solutions with hydrochloric acid; cool and extract in a separatory funnel with 4 portions of washed ether, using about 40 cc. altogether. Evaporate the ethereal solutions at room temperature, dry over sulphuric acid and weigh. If the residue is considerably discolored or gummy, re-extract in the dry state with boiling petroleum ether (b. p. 40°C. or below) not less than 15 times; evaporate the solvent, dry and weigh. The residue should now be white, crystalline vanillin, with a melting point of approximately 259 260 METHODS OF ANALYSIS [Chap. 80°C. A small amount of this residue, dissolved in 2 drops of concentrated hydro- chloric acid, should develop a pink color upon the addition of a crystal of resorcin. Evaporate at room temperature the original ether extract of the sample, from which the vanillin has been removed by means of ammonium hydroxid, and dry over sulphuric acid. The residue, if pure coumarin, should melt at approximately 67°C. and should respond to Leach's test for coumarin as follows: A small por- tion of the residue, dissolved in not more than 0.5 cc. of hot water, should yield a brown precipitate upon the addition of a few drops of N/10 iodin. This pre- cipitate finally gathers in green flecks, leaving a clear, brown solution. The reaction is especially marked if the reagent is applied with a glass rod to a few drops of the solution on a white plate or tile. $ NORMAL LEAD NUMBER'.— TENTATIVE. To a 10 cc. aliquot of the filtrate from the lead acetate precipitate, as obtained in 4, add 25 cc. of water, 0.5-1.0 cc. of sulphuric acid, and 100 cc. of 95% alcohol by volume. Let stand overnight, filter on a Gooch crucible, wash with 95% alcohol, dry at a moderate heat, ignite at low redness for 3 minutes, taking care to avoid the reducing flame, and weigh. Conduct a blank determination employing water containing 4 or 5 drops of glacial acetic acid in place of the sample. The normal lead number is calculated by the following formula: p ^ 100X0.6831(S-W) ^ ^3^^^ ^^ _ ^^^ .^ ^,^^.^^ p = normal lead number (grams of metallic lead in the precipitate obtained from ICO cc. of the sample); S = grams of lead sulphate corresponding to 2.5 cc. of the lead acetate solu- tion as determined in a blank analysis; and W = grams of lead sulphate obtained in 10 cc. of the filtrate from the lead acetate precipitate, as obtained in 4. 7 TOTAL SOLIDS.-TENTATIVE. Proceed as directed under JX, 4, employing 10 grams of the sample. 8 ASH.-OFFICL\L. Evaporate 10 grams of the extract and determine the ash as directed under vin, 4. 9 ASH CONSTITUENTS.— TENTATIVE. Proceed as directed under III or XXVIII, 21-28, inclusive. 10 SUCROSE.— TENTATIVE. Determine as directed under VIII, 14 or 18. VANILLA RESINS. 11 Qualitative Test. — Tentative. Place 50 cc. of the extract in a glass dish and evaporate the alcohol on a water bath. When the alcohol is removed, make up to about the original volume with hot water. If alkali has not been used in the manufacture of the extract, the resins will appear as a flocculent red to brown residue. Acidify with acetic acid to free the resins from the bases, separating the resins completely and leaving a partly decolorized, clear, supernatant liquid after standing a short time. Collect the resins on a filter, wash with water and reserve the filtrate for further tests. XX] FLAVORING EXTRACTS 261 Place a portion of the filter with the attached resins in a few cc. of dilute potas- sium hydroxid solution. The resins are dissolved, giving a deep red solution; acidify, and the resins are precipitated. Dissolve a portion of the resins in alcohol. To one portion add a few drops of ferric chlorid solution; to another portion hydrochloric acid; neither produces any marked change in color. Most resins, however, in alcoholic solution give color reactions with ferric chlorid or hydrochloric acid. To a portion of the filtrate obtained above add a few drops of basic lead acetate solution. The precipitate is so bulky as to almost solidify, due to the excessive amount of organic acids, gums and other extractive matter. The filtrate from this precipitate is almost colorless. Test another portion of the filtrate from the resin for tannin with a solution of gelatin. Tannin is present in varying but small quantities, but should not be present in great excess. 12 METHYL ALCOHOL.-TENTATIVE. Proceed as directed under X\1I, 16, 17 or 18, using the distillate from tlie de- termination of alcohol, 2. 13 COLOR VALUE.— TENTATIVE. Pipette 2 cc. of the extract into a 50 cc. graduated flask and make up to the mark with a mixture of equal parts of 95% alcohol by volume and water. Determine the color value of this diluted extract in terms of red and yellow by means of a Lovibond tintometer, using a 1 inch cell. To obtain the color value of the original extract, multiply the figures for each color by 25. 1 4 RESIDUAL COLOR AFTER PRECIPITATION WITH LEAD ACETATES-TENTATIVE. Determine the color value, in terras of red and yellow, of the filtrate from the lead acetate precipitate as obtained in 4, using a 1 inch Lovibond cell. Multiply the reading by 2 to reduce the results to the basis of the original extract. If the actual reading of the solution is greater than 5 red and 15 yellow, as may happen if the extract is highly colored with caramel, a ^ or i inch cell should be employed, and the readings multiplied, respectively, by 4 or 8. Divide the figures for red and yellow, respectively, by the corresponding figures of the original extract and mul- tiply the quotients by 100, to obtain the percentages of the 2 colors remaining in the lead acetate filtrate. Calculate also the ratio of red to yellow in both extract and lead acetate filtrate. COLORS INSOLUBLE IN AMYL ALCOHOL. 15 Modified ManIINATION. clave at 117°-120°C. for 20 minutes, allow the flask to cool somewhat, remove and chill under running water. Partially neutralize the excess of acid by adding 7.5 cc. of 10% sodium hj^droxid solution, free from carbonates, dilute to tlie mark and mix. Make a preliminary reading on 20 cc. to ascertain the volume to use to obtain a reading of approximately S mm. and transfer to a 500 cc. graduated flask. Add 10 cc of 10% sodium hydroxid solution and 30 cc. of saturated picric acid solution (1.2%). Mix and rotate for 30 seconds and let stand exactly 4\ minutes. Dilute to the mark at once with water, shake thoroughly and read in a Duboscq colori- meter, comparing the color with N/2 potassium dichromate solution, set at 8 mm. If the reading is too high or too low (above 9.5 or below 7 mm.), calculate the quantity necessary to obtain a reading of about 8 mm. The strength of the dichro- mate solution used must be checked against a standard creatin solution. To obtain the values, divide 81 by the reading and multiply by the volume factor to obtain mg. of creatinin; this value multiplied by 1.16 gives creatin, which, divided by the weight of the sample and multiplied by 100 gives the per cent of creatin. 276 METHODS OF ANALYSIS [Chap. The use of Kober's shade and the painting of the plunger, as suggested for this nephelometer, assists in getting a sharper end point, relieves the eye strain and may be employed if desired. Example. — 20 grams of meat are extracted with water as in 9, and the extract diluted to 500 cc. ; 150 cc. of this latter solution (equivalent to 6 grams of meat) are treated as in 11. The filtrate thus obtained is then evaporated and hydrolyzed as above and then diluted to 50 cc. ; 25 cc. of this last solution are treated with sodium hydroxid solution and picric acid solution as directed above and diluted to 500 cc. This latter solution gives a reading of 9 mm. -Q X ^ = 18 mg. creatinin; 0.018X1.16X100 -„,^ t; = 0.3o% creatin. (In chopped meat, sausage, deviled meat, etc.) 17 Qualitative Test. — Tentative. Treat 5-6 grams of the sample with boiling water for 2-3 minutes, cool the mix- ture and test the supernatant liquid with iodin solution. In using this test, a small amount of starch may be present as the result of the use of spices. If a marked reaction is given, however, it may be concluded that starch or flour has been added, and a quantitative determination maj^ be made. The qualitative method may be replaced by a microscopic examination, which discloses not only the presence of added starch, but also the variety employed. 18 Mayrhofer Method, Price Modification*. — Tentative. Treat in a 200 cc. beaker 10 grams of the finely divided sample with 75 cc. of an 8% solution of potassium hydroxid in 95% alcohol by volume and heat on a steam bath until all the meat is dissolved (30-45 minutes). Add an equal volume of 95% alcohol, cool and allow to stand for at least an hour. Filter by suction through a thin layer of asbestos in a Gooch crucible. Wash twice with warm 4% potassium hydroxid in 50% alcohol by volume and then twice with warm 50% alcohol. Dis- card the washings. Retain as much of the precipitate in the beaker as possible until the last washing. Place the crucible with contents in the original beaker, add 40 cc. of water and 25 cc. of concentrated sulphuric acid. Stir during the addi- tion of the acid and make sure that the acid comes in contact with all the precipi- tate. Allow to stand about 5 minutes, add 40 cc. of water and heat just to boiling, stirring constantly. Transfer the solution to a 250 cc. graduated flask, add 2 cc. of 20% phosphotungstic acid solution, allow to cool to room temperature and make up to the mark with water. Filter through a starch-free filter paper, pipette 100 cc. of the filtrate into a 200 cc. graduated flask, neutralize with sodium hydroxid .solution, make up to volume and determine the dextrose present in a 50 cc. portion of the filtrate, as directed under VIII, 25, titrating the cuprous oxid precipitate as directed under VIII, 29. The weight of the dextrose multiplied by 0.9 gives the weight of the starch. GLYCOGEN. 19 Qualitative Test^. — Tentative. Boil 50 grams of the macerated sample with 50 cc. of water for 15-30 minutes. Filter the broth through moistened filter paper or fine linen. To a portion of the filtrate in a test tube add a few drops of a mixture of 2 parts of iodin, 4 of potassium XXI] MEAT AND MEAT PRODUCTS 277 iodid and 100 of water. In the presence of a considerable amount of glycogen the latter produces a dark brown color, which is destroyed by heating and reappears on cooling. When starch is present, it may be precipitated by treating the water extract with 2 volumes of glacial acetic acid, filtering and applying the test for glycogen to the filtrate. Trowbridge and Francis Method". — Tentative. 20 PREPARATIO>f OF SOLUTION. Weigh out by difference about 25 grams of the finely ground and thoroughly mixed sample. Place in a 400 cc. beaker and mix with 50 cc. of potassium hydroxid solution (1| to 1), free from carbonate. Cover the beaker with a watch glass and digest on the water bath for 2 hours, with occasional stirring. At the end of the 2 hours, dilute to approximately 200 cc. with cold water. Add to the solution an equal volume of 95% alcohol by volume, cover with a watch glass and set aside for 10-12 hours. Decant the supernatant liquid through a folded 18.5 cm. filter, allowing the glycogen to remain in the beaker and wash by decantation with 66% alcohol (2 volumes of 95% alcohol to 1 of water) until the glycogen is white, or nearly so. Usually about 4 washings are required. Transfer the washed precipitate from the beaker to the filter and wash 2-3 times with 66% alcohol. The solution filters slowly and the funnel should be covered with a watch glass to prevent excessive evaporation. The albuminous substance present retards the filtration if permitted to dry on the paper. If the washing by decantation is not made nearly complete, it will be difficult to obtain the glycogen free from the coloring matter. After the washing is completed, close the bottom of the funnel by a piece of rub- ber tubing and a pinch-cock. Fill the funnel with warm water, cover with the watch glass and let stand 2-3 hours, or overnight. Open the pinch-cock and allow all of the solution to pass through the filter into a beaker. Close the funnel with the pinch-cock and fill with warm water as before. Allow this water to remain in the funnel for an hour and then filter as before. At first the glycogen solution appears quite turbid. This washing with warm water should be continued until the filtrate becomes perfectly clear. To the solution of glycogen in water, add double its volume of 95% alcohol by volume and let stand overnight to complete the repre- cipitation of the glycogen. Filter and wash as before with 66% alcohol. 21 DETERMINATION. If desired, the last filtration may be made through a tared Gooch crucible and the weight of glycogen determined after drying to constant weight. This gives results that are approximately correct. More satisfactory results are obtained by hydrolyz- ing the glycogen with dilute hydrochloric acid and determining the resultant dex- trose. Dissolve the glycogen on the filter in warm water as directed above, collect- ing the filtrate and washings in a 300 cc. graduated flask and keeping the volume within 225 cc. Add 12.5 cc. of hydrochloric acid (sp. gr. 1.19) to the combined fil- trate and washings, mix and place in a boiling water bath for 3 hours. Cool, neu- tralize with sodium hydroxid solution, cool again, make up to volume with water and determine dextrose in an aliquot of the solution as directed under VIII, 54, determining the reduced copper as directed under VIII, 29. Multiply the cor- responding weight of dextro'se by 0.9 to obtain its equivalent of glycogen and correct this result for dilution to obtain the per cent of glycogen in the sample. 278 METHODS OF ANALYSIS [Chap. SUGAR^.-TENTATIVE. 22 REAGENTS. (a) Mercuric nitrate solution. — Warm 220 grams of yellow mercuric oxid with 300 cc. of water and treat with small portions of nitric acid, stirring until dissolved. Make up to 1 liter and filter. (b) Phosphotungstic acid solution. — Prepare a 20% solution of phosphotungstic acid in 2.5% hydrochloric acid. 23 DETERMINATION. Boil 100 grams of the sample with about 350 cc. of water for about 20 minutes, cool, add an excess (10-30 cc.) of the mercuric nitrate solution, nearly neutralize with sodium hydroxid solution and make up to 500 cc, exclusive of fat. Mix thor- oughly, allow the mixture to settle and decant the clear liquid through a large, dry, folded filter. To an aliquot of the filtrate add 1-2 cc. of concentrated hydrochloric acid for each 100 cc, heat to boiling and saturate thoroughly with a rapid current of hydrogen sulphid. Remove the excess of hydrogen sulphid by means of a cur- rent of air, cool, make up to a definite volume with water and filter. To an aliquot of the filtrate add an excess of the phosphotungstic acid solution, noting the in- crease in volume of the solution caused by this addition and place in an ice box for several hours or overnight. Filter, introduce 50 cc of the filtrate into a 400 cc. beaker, neutralize with concentrated sodium hydroxid solution, add 50 cc. of Soxh- let's solution [VIII, 19], heat so that boiling begins in 4 minutes, boil 2 minutes and filter through an alundum crucible of suitable porosity, using very gentle suction. If the filtrate is green or yellow, refilter through the same crucible until the fil- trate is clear blue. Wash the precipitate with a very small amount of 5% sodium hydroxid solution, refiltering the washings if they are turbid. Dissolve the precipi- tated cuprous oxid in nitric acid (1 to 1) and determine copper as directed under VIII, 29. Find the corresponding amount of dextrose or invert sugar from VIII, 27, and calculate the per cent in the original sample by proper correction for the various aliquots taken in the determination. To convert invert sugar to sucrose multiply by the factor 0.95. NITRATES. Sclildsing-W agner Method^. — Tentative. 2A REAGENT. Ferrous chlorid solution. — Dissolve nails or other small pieces of iron in concen- trated hydrochloric acid, keeping an excess of iron present until the evolution of gas ceases. Keep the solution in 50 cc. glass-stoppered bottles entirely filled. Employ only freshly opened bottles of the reagent for the determination. 25 APPARATUS. Provide a 250 cc. flask with a 2-holed rubber stopper. Through one of the holes pass the stem of a funnel having a glass stop-cock, and into the other fit a delivery tube leading downward at an angle from the flask to a trough containing water. Terminate the upper end of the delivery tube just below the rubber stopper in the flask and place the lower end under the surface of the water in the trough, the exit being immediately beneath the mouth of an inverted measuring tube, filled with 40% potassium hydroxid solution. Cover the trough end of the delivery tube with a piece of rubber tubing. Midway on the delivery tube between the flask and the measuring tube place a short length of rubber tubing and a pinch-cock. XXI] MEAT AND MEAT PRODUCTS 279 26 DETERMINATION. Extract 100 grams of finely ground meat by boiling repeatedly with successive small portions of water, decanting the extracts through a muslin or paper filter into a casserole, and concentrate the combined extracts to a volume of about 50 cc. Introduce 50 cc. of the ferrous chlorid solution and 50 cc. of 10% hydrochloric acid into the flask, close the stop-cock of the funnel, open the pinch-cock on the deUvery tube, move the end of the latter so that escaping air will not pass into the measuring tube, and boil the contents of the flask until the air is expelled, as indicated by a slight pressure against the fingers when the rubber tubing is compressed after mo- mentary removal of the flame. Now close the delivery tube with the pinch-cock and place the exit end beneath the measuring tube. Introduce the concentrated extract of the sample into the flask, a little at a time, through the funnel tube, opening the pinch-cock on the delivery tube and boiling the contents of the flask at intervals to force the nitric oxid gas into the measuring tube. Finally rinse the casserole and the funnel tube with a little boiled water, add the rinsings to the con- tents of the evolution flask in the manner just described and boil until nitric oxid no longer passes over into the measuring tube. Calculate the volume of nitric oxid at 0°C. and 760 mm. pressure. One cc. of nitric oxid at 0°C. and 760 mm. pressure is equivalent to 0.004512 gram of potassium nitrate. Phenoldisulphonic Acid Method^. — Tentative. 27 REAGENTS. (a) Phenoldisulphonic acid solution. — Heat 6 grams of phenol with 37 cc. of con- centrated sulphuric acid on a water bath, cool and add 3 cc. of water. (b) Standard comparison solution. — Dissolve 1 gram of pure, dry potassium ni- trate in water and dilute to 1 liter. Evaporate 10 cc. of this solution to dryness on a steam bath, add 2 cc. of the phenoldisulphonic acid solution, mix quickly and thoroughly by means of a glass rod, heat for about a minute in a steam bath and dilute to 100 cc. One cc. of this solution is equivalent to 0.1 mg. of potassium ni- trate. Prepare a series of standard comparison tubes by introducing amounts ranging from 1-20 cc. of this solution (0.1-2.0 mg. of potassium nitrate) into 50 cc. Nessler tubes, adding 5 cc. of strong ammonium hydroxid to each and diluting to 50 cc. These standard tubes are permanent for several weeks if kept tightly stoppered. 28 DETERMINATION. Weigh 1 gram of the sample into a 100 cc. flask, add 20-30 cc. of water and heat on a steam bath for 15 minutes, shaking occasionally. Add 3 cc. of saturated silver sulphate solution for each per cent of sodium chlorid present, then 10 cc. of basic lead acetate solution and 5 cc. of alumina cream, shaking after each addition. Make up to the mark with water, shake and filter through a folded filter, returning the filtrate to the filter until it runs through clear. Evaporate 25 cc. of the filtrate to dryness, add 1 cc. of the phenoldisulphonic acid solution, mix quickly and thor- oughly by means of a glass rod, add 1 cc. of water and 3 or 4 drops of concentrated Bulphuric acid and heat on a steam bath for 2-3 minutes, being careful not to char the material. Then add about 25 cc. of water and an excess of ammonium hydroxid, transfer to a 100 cc. graduated flask, add 1-2 cc. of alumina cream if not perfectly clear, dilute to the mark with water and filter. Fill a 50 cc. Nessler tube to the mark with the filtrate and determine the amount of potassium nitrate present in I 280 METHODS OF ANALYSIS [Chap. the sample by comparison with the standard comparison tubes. If the solution is too dark for comparison with the standards, dilute with water and correct the result accordingly. 29 PRESERVATIVES.— TENTATIVE. Proceed as directed under X. 30 METALS.-TENTATIVE. Proceed as directed under XII. 31 COLORING MATTERS.-TENTATIVE. Proceed as directed under XI. MEAT EXTRACTS AND SIMILAR PRODUCTS. 32 PREPARATION OF SAMPLE.-TENTATIVE. Remove liquid and semi-liquid meat extracts and similar preparations from the container and mix thoroughly before sampling. A little heating expedites the mixing of pasty extracts. In many liquid preparations a sediment forms which should be carefully removed from the bottom of the container and included in the sample. If the sample is in the form of cubes, grind 10-12 of the cubes in a mortar. 33 MOISTURE.-TENTATIVE. Proceed ae directed under VIII, 2, employing about 2 grams of powdered prepa- rations, about 3 grams of pasty preparations, or 5-10 grams of liquid extracts, according to the solid content. Dry the powdered preparations directly without admixture. Dissolve the pasty preparations in water and dry with sufficient ignited sand, asbestos or pmnice stone to absorb the solution. When glycerol is present, proceed as directed under VIII, 3. 34 ASH.-OFFICIAL. Proceed as directed under VIII, 4. Add sufficient water tt) pasty preparations to effect solution and evaporate to dryness in order that the solids may be distrib- uted evenly over the bottom of the dish. 35 TOTAL PHOSPHORUS.— TENTATIVE. Proceed as directed under 5. 30 CHLORIN.— TENTATIVE. Dissolve about 1 gram of the sample, prepared as directed in 32, in 20 cc. of 5% sodium carbonate solution and proceed as directed under III, 18. 37 FAT.— TENTATIVE. Transfer the residue from the determination of moisture to a continuous extrac- tion apparatus and proceed as directed under VIII, 10. 38 TOTAL NITROGEN.— OFFICIAL. Proceed as directed under I, 18, 21 or 23. XXI] MEAT AND MEAT PRODUCTS 281 39 INSOLUBLE PROTEIN' ".-TENTATIVE. Dissolve 5 grams of powdered preparations, 8-10 grams of pasty extracts, or 20- 25 grams of fluid extracts, in cold water. Filter and wash with cold water. Trans- fer the filter paper and contents to a Kjeldahl flask and determine nitrogen as di- rected under 1, 1 8, 21 or 23. However, i f a large amount of insoluble matter is pres- ent, transfer the weighed sample to a graduated flask, make up to a definite volume, shake thoroughly, filter through a folded filter and determine nitrogen in an aliquot of the filtrate. Deduct the percentage of nitrogen in the total filtrate from the percentage of total nitrogen, 38, to obtain the percentage of nitrogen in the insol- uble protein. Multiply this percentage of nitrogen by 6.25 to obtain the percentage, of insoluble protein. 40 COAGULABLE PROTEIN.-TENTATIVE. Prepare a solution of the sample as directed in 39. Employ as large an aliquot of the filtrate as practicable or an aliquot of the filtrate from the insoluble protein, 39, and neutralize to phenolphthalein by the addition of acetic acid or sodium hydroxid, whichever may be necessary, add 1 cc. of N/1 acetic acid, boil for 2-3 minutes, cool to room temperature, dilute to 500 cc. and pass through a folded filter. Determine nitrogen in 50 cc. of the filtrate as directed under I, 18, 21 or 23. Ten times the percentage of nitrogen so obtained subtracted from the percentage of soluble nitrogen (total nitrogen minus the percentage of nitrogen occurring as insoluble protein) gives the percentage of nitrogen present as coagulable protein. Multiply this figure by 6.25 to obtain the percentage of coagulable protein in the sample. 41 AMMONIA.-TENTATIVE. Mix 1 gram of meat extract with 2 cc. of N/1 hydrochloric acid, wash into a Folin apparatus with about 5 cc. of water and proceed as directed under 15. 42 PROTEOSES AND GELATIN".— TENTATIVE. Evaporate the filtrate from 40 to a small volume and saturate with zinc sulphate (about 85 grams to 50 cc, avoiding such an excess as would later cause bumping). Let stand several hours, filter and wash the precipitate with saturated zinc sul- phate solution, place the filter and precipitate in a Kjeldahl flask and determine ni- trogen as directed under I, 1 8, 21 or 23. Or, if the precipitate is voluminous, which rarely happens, make up to a definite volume with saturated zinc sulphate solution, filter and determine the nitrogen in an aliquot of the filtrate, as directed under I, 18, 21 or 23, and subtract the nitrogen thus obtained from the nitrogen in the filtrate from the coagulable protein to obtain the nitrogen of the precipitated protein (proteoses and gelatin). 43 GELATIN.— TENTATIVE. Prepare a 50% solution of the sample, using hot water. Allow to cool and place in an ice box for 2 hours. If gelatin is present, the solution will set. The ratio of total creatinin to total nitrogen in a normal meat extract (1 : 1.5) assists in determining the presence of gelatin or gelatin derivatives. The ratio is decreased when gelatin or gelatin derivatives are present in any considerable amount. 282 METHODS OF ANALYSIS [Chap. AMINO NITROGEN. Van Slyke Method^''. — Tentative. 44 REAGENTS. (a) Alkaline ■permanganate solution. — Dissolve 50 grams of potassium permanga- nate and 25 grams of potassium hj'droxid in sufficient water to make 1 liter. (b) Sodium nitrite solution. — Dissolve 30 grams of sodium nitrite in sufficient water to make 100 cc. (C) Glacial acetic acid. FIG. 10. VAN SLYKE APPARATUS FOR THE DETERMINATION OF AMINO NITROGEN. {By courtesy of the Journal of Biological Chemistry.) 45 APPARATUS. Employ the apparatus shown in Figs. 10 and 11, the former illustrating the man- ner in which the entire apparatus is arranged and the latter showing the details XXI] MEAT AND MEAT PRODUCTS 283 of the deaminizing bulb and connections, the alkaline permanganate solution. The Hempel gas pipette is filled with 46 DETERMINATION. Fill with water the burette (F), the capillary tube leading to the Hempel pipette and also the other capillary as far as c. Introduce into A sufficient glacial acetic acid to fill one fifth of D, the tube (A) being etched with a mark to measure this P'pette FIG. 11. DETAILS OF THE DEAMINIZING BULB AND CONNECTION. (By courtesy of the Journal of Biological Chemistry.) amount. Allow the acid to run into D, the cock c being turned so as to allow the air to escape from D. Pour the sodium nitrite solution into A until D is full of solu- tion and enough e.xcess is present to rise a little above the cock into A. A is also marked for measuring off this amount. Then close the gas exit from D at c, and, a being open, shake D for a few seconds until the liquid is forced down to the 20 cc. mark in D. Then close a, open c and shake the apparatus rapidly with the motor for 2 minutes, these operations being for the purpose of expelling all the air from D. Then turn c and / so that D and F are connected. 284 METHODS OF ANALYSIS [Chap. Measure off in B 10 c,-. or less, as the case may be, of the solution of the sample containing not more than 20 mg. of amino nitrogen (about 1-2 grams of the sample) and allow it to run into D. Connect D with the motor as shown in Fig. 10 and shake for 5 minutes. If the solution of the sample is viscous and threatens to foam over, rinse out B, and then through it introduce a little caprylic alcohol into D, or, if it is known beforehand that the sample will cause excessive foaming, introduce a little caprylic alcohol into D through B, rinsing B with alcohol and ether or drying with a roll of filter paper before adding the solution of the sample. During the shaking there is an evolution of nitrogen mixed with nitric oxid,the gases being collected in F: Force all the gas in D into F by opening a and filling D with liquid from A. Connect F with the Hempel pipette and force the gas into the latter by means of the leveling bulb, allowing the cock a to remain open during this and the succeeding operation in order to permit displacement of the liquid in D by the nitric oxid formed in the interval. Connect the driving rod with the pipette by lifting the hook from the shoulder of D and placing the other hook, on the opposite side of the driving rod, over the horizontal lower tube of the pipette. Shake the pipette rather slowly for a minute which, with any but almost completely exhausted permanganate solutions, completes the absorption of nitric oxid. Then return the gas to the burette, adjust the level with the leveling bulb and note the volume of nitrogen, the temperature and barometric pressure, and calculate the volume of nitrogen under standard conditions of temperature and pressure. Ob- tain the corresponding weight of nitrogen, divide the latter by 2, and from the quotient calculate the apparent per cent of amino nitrogen in the sample. Cor- rect the result for a blank test performed as above, using 10 cc. of water instead of the solution of the sample. The amount of gas obtained in the blank is usually 0.3-0.4 cc, and nitrite solutions giving a much larger correction should be rejected. In the case of beef extracts and similar preparations 5 minutes is sufficient time to allow for the completion of the reaction in D. In general the same time serves for the decomposition of alpha-amino acids but with ammonia, methylamin and most amines other than alpha-amines 1-1| hours should be allowed. For determi- nations on such substances mix the solution of the sample with the reagents as de- scribed above, allow the mixture to stand in the apparatus till the end of the re- quired time, and conclude the reaction by shaking the apparatus with the motor for 2-3 minutes. Continue the determination from this point as directed above. 47 ACID ALCOHOL-SOLUBLE NITROGENi^.— TENTATIVE. Transfer 10 cc. of an aqueous solution of the sample (10 grams of the sample dissolved in sufficient water to make 100 cc.) or, if the sample is insoluble in water, 1 gram of the sample and 10 cc. of water, to a 200 cc. glass-stoppered measuring cylinder, add 1.2 cc. of 12% hydrochloric acid, mix and add absolute alcohol to the 200 cc. mark. Mix thoroughly and set aside for several hours. If necessary make up to volume, filter, transfer 100 cc. of the filtrate to a Kjeldahl flask, evaporate the alcohol on a water bath and determine nitrogen in the residue as directed under I, 18, 21 or 23. 48 CREATIN.-OFFICIAL. Dissolve about 7 grams of the sample in cold (20°C.) ammonia-free water in a 150 cc. beaker, transfer the solution to a 250 cc. measuring flask, dilute to the mark XXI] MEAT AND MEAT PRODUCTS 285 and mix thoroughly. Transfer a 20 cc. aliquot of this solution to a 50 cc. meas- uring flask and proceed as directed under 16. Subtract from the combined creati- nin value the equivalent of the pre-formed creatinin, 49, and multiply the difference by 1.16 to convert into creatin. Express the result as per cent of creatin. 49 CREATININ.-OFFICIAL. For creatinin in beef extract measure about 5 cc. of the solution employed in 48 into a 500 cc. measuring flask, add 10 cc. of 10% sodium hydroxid solution and 30 cc. of the saturated picric acid solution (1.2%), mix and rotate for 30 seconds. Allow- to stand exactly 4^ minutes, then dilute to the mark at once with water. Shake thoroughly and read the depth of color after standing. If the reading is less than 7 or over 9.5 mm., repeat, calculating the quantity of solution necessary to obtain a reading of about 8 mm. Express the result as per cent of creatinin, making the calculations as indicated under 16. GLYCEROL. 50 Cook Method^*.— Tentative. Weigh 2 grams of a solid or 5 grams of a liquid preparation in a small lead dish or Hofmeister Schalchen containing 20 grams of ignited sand. Transfer the dish and its contents to a mortar containing more ignited sand and several grams of anhydrous sodium sulphate and mix thoroughly. Transfer the mixture, including the dish, to a Soxhlet apparatus which has a piece of cotton placed in the side arm to prevent solid particles from being siphoned over. Extract the entire mass with redistilled anhydrous acetone for 10 hours. Distil the acetone from the extract, carefully re- moving the last trace by means of a vacuum pump. Take up the residue in water, add 5 cc. of 10% silver nitrate solution, make up to a volume of 100 cc, shake, allow to stand overnight, filter and determine glycerol in an aliquot of the filtrate as di- rected under XIX, 6, beginning at the point "Add * * * 30 cc. of the strong potassium dichromate solution". With solid meat and yeast extracts a blank of 0.5-1.0 % is obtained in most cases. 51 SUGAR.-TENTATIVE. Heat 20 grams of the sample with about 200 cc. of water on a steam bath until all soluble substances have gone into solution, cool and proceed from this point as directed under 23. Reducing sugar up to 0.5% may be present as a natural con- stituent of meat extracts. 52 PRESERVAXrVES.-TENTATIVE. Proceed as directed under X. 53 METALS.— TENTATIVE. Proceed as directed under XII. 54 NITRATES.-TENTATIVE. Proceed as directed under 26 or 28. 286 METHODS OF ANALYSIS BIBLIOGRAPHY. > J. Assoc. Official Agri. Chemists, 1915, 1: 230. 2 J. Am. Chem. Soc, 1906, 28: 1485. 3 J. Assoc. Official Agri. Chemists, 1915, 1: 174. * U. S. Bur. Chem. Bull. 162, p. 97. 5 Abs. Z. Nahr. Hyg. Waar., 1896, 10: 173. ' J. Ind. Eng. Chem., 1910, 2: 21, 215. ^ J. Assoc. Official Agri. Chemists, 1915, 1: 177. * Tiemann. Anleitung zur Untersuchung von Wasser. 1870, p. 56; Wiley. Prin- ciples and Practice of Agricultural Analysis. 2nd ed., 1906-14, 2:397; U. S. Bur. Chem. Bull. 13 (X), p. 1403. 8 U. S. Bur. Chem. Bull. 13 (X), p. 1405. 1" Allen. Commercial Organic Analysis. 4th ed., 1909-14, 8: 407. " Z. anal. Chem., 1895, 34: 562; U. S. Bur. Chem. Bull. 54. '* J. Biol. Chem., 1911, 9: 185; 1912, 12: 275; 1913, 16: 121; 1915, 23: 407. " J. Am. Chem. Soc, 1914, 36: 1551. " J. Assoc. Official Agri. Chemists, 1915, 1: 279. XXII. DAIRY PRODUCTS. MILK. 1 SOLIDS.— OFFICIAL. Heat 3-5 grams of the milk at the temperature of boiling water until it ceases to lose weight, using a tared, flat-bottomed dish of not less than 5 cm. diameter. If desired, previously place 15-20 grams of pure, dry sand in the dish. Cool in a desiccator and weigh rapidly to avoid absorption of h3'groscopic moisture. 2 ASH.— OFFICLAL. Weigh about 20 grams of the milk in a tared dish, add 6 cc. of nitric acid, evap- orate to dryness and ignite at a temperature just below redness until the ash is free from carbon. 3 TOTAL NITROGEN.-OFFICL/^L. Place about 5 grams of the milk in a Kjeldahl digestion flask and proceed, without evaporation, as directed under I, 18, 21 or 23. Multiply the percentage of nitro- gen by 6.38 to obtain the equivalent percentage of nitrogen compounds. CASEIN. (This determination should be made while the milk is fresh, or nearly so. When it is not practicable to make this determination within 24 hours, add 1 part of formaldehyde to 2500 parts of milk and keep in a cool place.) 4 Method I.— Official. Place 10 grams of the milk in a beaker with 90 cc. of water at 40°-42°C. and add at once 1.5 cc. of 10% acetic acid. Stir and let stand 3-5 minutes. Then decant on a filter, wash by decantation 2-3 times with cold water and transfer the precipi- tate to the filter. Wash once or twice on the filter. The filtrate should be clear, or very nearly so. If the first portions of the filtrate are not clear, repeat the fil- tration, after which complete the washing of the precipitate. Determine nitrogen in the washed precipitate and filter paper as directed under I, 18, 21 or 23, mul- tiply by 6.3S and calculate the percentage of casein. In samples of milk which have been preserved, the acetic acid should be added in small portions, a few drops at a time, with stirring, and the addition continued until the liquid above the precipitate becomes clear, or very nearly so. 5 Method II.— Official. To 10 grams of the milk add 50 cc. of water at 40°C., then 2 cc. of alum solution saturated at 40°C., or higher. Allow the precipitate to settle, transfer to a filter and wash with cold water.' Determine nitrogen in the precipitate and filter paper as directed under I, 18, 21 or 23, multiply by 6. .38 and calculate the percent- age of casein. 287 288 METHODS OF ANALYSIS [Chap. ALBUMIN. 6 Method I. — Tentative. Exactly neutralize the filtrate, obtained in 4, with sodium hydroxid solution, add 0.3 cc. of 10% acetic acid and heat on a steam bath until the albumin is com- pletely precipitated. Collect the precipitate on a filter, wash with cold water and determine the nitrogen as directed under I, 18, 21 or 23, multiply by 6.38 and cal- culate the percentage of albumin. 7 Method II. — Tentative. To the filtrate obtained from the casein determination, 5, add 0.3 cc. of 10% acetic acid, boil until the albumin is completely precipitated and proceed as directed in 6. LACTOSE. Optical Method. — Tentative. 8 REAGENTS. (a) Acid mercuric nitrate solution. — Dissolve mercury in double its weight of nitric acid (sp. gr. 1.42) and dilute with an equal volmne of water. (b) Mercuric iodid solution. — Dissolve 33.2 grams of potassium iodid and 13.5 grams of mercuric chlorid in 20 cc. of glacial acetic acid and 640 cc. of water. 9 DETERMINATION. Determine the specific gravity of the milk by means of a delicate hydrometer or, if preferred, a pycnometer. The quantity of sample to be taken for the deter- mination varies with the specific gravity and is to be measured at the same tempera- ture at which the specific gravity is taken. The volume to be measured will be found in 10 which is based upon twice the normal weight of lactose (32.9 grams per 100 metric cc.) for the Ventzke sugar scale. Place the quantity of milk indicated in 10 in a flask graduated at 102.6 cc. Add 1 cc. of the acid mercuric nitrate solution or 30 cc. of the mercuric iodid solution (an excess of these reagents does no harm), fill to the mark, shake, filter through a dry filter and polarize. It is not necessary to heat before polarizing. If a 200 mm. tube is used, divide the polariscope reading by 2 (or, if a 400 mm. tube is used, by 4) to obtain the per cent of lactose in the sample. 10 Table 19. Volumes of milk corresponding to a lactose double normal weight^ VOLUME OF MILK FOS A. volume of milk for a SPECIFIC GRAVITT OP LACTOSE DOUBLE NOR- specific gravity of lactose double nor- MILK MAL WEIGHT MILK mal weight (ventzke scale) (ventzke scale) 1.024 CC. 64.25 1.030 cc. 63.90 1.025 64.20 1.031 63.80 1.026 64.15 1.032 63.75 1.027 64.05 1.033 63.70 1.028 64.00 1.034 63.65 1.029 63.95 1.035 63.55 1.036 63.50 XXII] DAIRY PRODUCTS 289 1 1 Gravimetric Method. — Official. Dilute 25 grams of the milk with 400 cc. of water in a 500 cc. graduated flask, add 10 cc. of copper sulphate solution [VIII, 19 (a)] and about 7.5 cc. of a potas- sium hydroxid solution of such strength that 1 volume is just sufficient to pre- cipitate completely the copper as hydroxid from 1 volume of the copper sulphate solution. Instead of potassium hydroxid solution of this strength, 8.8 cc. of N/2 sodium hydroxid solution may be used. After the addition of the alkali solution the mixture must still have an acid reaction and contain copper in solution. Fill the flask to the 500 cc. mark, mix, filter through a dry filter and determine lactose in an aliquot of the filtrate as directed under VIII, 46 or 48. FAT. 12 Roese-Gottlieb Method'^. — Official. Weigh 10-11 grams of the milk into a Rohrig tube or some similar apparatus, add 1.25 cc. of concentrated ammonium hydroxid (2 cc. if the sample is sour) and mix thoroughly. Add 10 cc. of 95% alcohol by volume and mix well. Then add 25 cc. of washed ether and shake vigorously for 30 seconds, then 25 cc. of petro- leum ether (redistilled slowly at a temperature below 60°C.) and shake again for 30 seconds. Let stand 20 minutes, or until the upper liquid is practically clear. Draw off as much as possible of the ether-fat solution (usually 0.5-0.8 cc. will be left) into a weighed flask through a small, quick-acting filter. The flask should always be weighed with a similar one as a counterpoise. Re-extract the liquid remain- ing in the tube, this time with only 15 cc. of each ether, shake vigorously 30 seconds with each and allow to settle. Draw off the clear solution through the small filter into the same flask as before and wash the tip of spigot, the funnel and the filter with a few cc. of a mixture of the 2 ethers in equal parts. For absolutely exact results the re-extraction must be repeated. This third extraction yields usually not more than about 1 mg. of fat (about 0.02% on a 4 gram charge) if the previous ether-fat solutions have been drawn off closely. Evaporate the ethers slowly on a •steam bath, then dry the fat in a boiling water oven to constant weight. Confirm the purity of the fat by dissolving in a little petroleum ether. Should a residue remain, remove the fat completely with petroleum ether, dry the residue, weigh and deduct the weight. Finally correct this weight b)^ a blank determina- tion on the reagents used. Babcock Method. — Official. 13 APPARATUS. (a) Standard Babcock test bottles. — The standard Babcock test bottles for milk and cream shall be as follows: (1) 8%, 18 gram, 6 inch milk test bottle.— The total per cent graduation shall be 8. The total height of the bottle shall be 150-165 mm. (5^-62 inches). The capac- ity of the bulb up to the junction with the neck shall be not less than 45 cc. The graduated portion of the neck shall have a length of not less than 63.5 mm. (2^ inches) and the neck shall be cylindrical for at least 9 mm. below the lowest and aljove the highest graduation marks. The graduations shall represent whole per cents, halves and tenths of a per cent. (2) 50%, 9 gram, 8 inch cream test bottle.— The total per cent graduation shall be 50. The total height' of the bottle shall be 150-165 mm. (5^61 inches). The capacity of the bulb up to the junction with the neck shall be not less than 45 cc. The graduated portion of the neck shall have a length of not less than 63.5 mm. (2^ 290 METHODS OF ANALYSIS [Chap. inches) and the neck shall be cylindrical for at least 9 mm. below the lowest and above the highest graduation marks. The graduations shall represent five per cents, whole and halves of a per cent. (3) 50%, 9 gram, 9 inch, cream test bottle. — Same as (2) except that the total height of the bottle shall be 210-225 mm. (8l~Sl inches). (b) Centrifuge. (C) Pipettes. — Graduated to deliver 17.6 cc. of water at 20°C. in 5-8 seconds. (d) Graduates. — Capacity 17.5 cc. or a Swedish acid bottle delivering that amount. CALIBRATION OF APPARATUS. 14 (a) Graduation. — The unit of graduation for all Babcock glassware shall be the true cc. (0.998877 gram of water at 4°C.). With bottles, the capacity of each per cent on the scale shall be 0.20 cc. With pipettes and graduates, the delivery shall be the intent of the graduation; and the graduation shall be read with the bottom of the meniscus in line with the mark. (b) Testing. — The method for testing Babcock bottles shall be calibration with mercury (13.5471 grams of clean, dry mercury at 20°C., to be equal to 5% on the scale), the bottle being previously filled to zero with mercury. The mercury and cork, alcohol and burette, and alcohol and brass plunger methods may be emploj'ed for the rapid testing of Babcock bottles, but the accuracy of all questionable bottles shall be determined by calibration with mercury. The method for testing pipettes and graduates shall be calibration by measuring in a burette the quantity of water (at 20°C.) delivered. (C) Limit of error. — For standard Babcock milk bottles the error at any point of the scale shall not exceed 0.1%. For standard Babcock cream bottles the error at any point of the scale shall not exceed 0.5 %. For standard milk pipettes the error shall not exceed 0.05 cc. For acid measures the error shall not exceed 0.2 cc. 15 DETERMINATION. Pipette 17.6 cc. of the carefully mixed sample into a test bottle and add 17.5 cc. of commercial sulphiu'ic acid (sp. gr. 1.S2-1.83). Mix and, when the curd is dissolved, centrifugalize for 4 minutes at the required speed for the machine used. Add boiling water, filling to the neck of the bottle, and whirl for 1 minute; again add boiling water so as to bring the fat within the scale on the neck of the bottle, and, after whirling for 1 minute more, read the length of the fat column, making the reading at 57°-60°C. at which temperature the fat is wholly liquid. The reading gives directly the per cent of fat in the milk. Details of the manipulation of the Babcock test and its application in the analy- sis of dairy products other than milk arc described by Farrington and WolP, and Van Slyke^ Added Water. (In conjunction with the copper, acetic or sour serum refraction method, the determination of the ash of the sour serum or of the acetic serum should be made in all cases where the indices of refraction fall below the minimum limit so as to eliminate all possibility of abnormal milk.) XXII] DAIRY PRODUCTS 291 16 ACETIC SERUM.-TENTATIVE. (a) Zeiss immersion refractometer reading. — To 100 cc. of milk at a temperature of about 20°C. add 2 cc. of 25% acetic acid (sp. gr. 1.035) in a beaker and heat the mixture, covered with a watch glass, in a water bath for 20 minutes at a tempera- ture of 70°C. Place the beaker on ice water for 10 minutes and separate the curd from the serum by filtering through a 12.5 cm. folded filter. Transfer about 35 cc. of the serum to 1 of the beakers that accompanies the control-temperature bath used in connection with the Zeiss immersion refractometer, and take the refrac- tometer reading at exactly 20°C., using a thermometer graduated to tenths of a degree. A reading below 39 indicates added water; between 39 and 40, the addition of water is suspected. (b) Ash. — Transfer 25 cc. of the serum to a flat-bottomed platinum dish and evaporate to dryness on a water bath. Then heat over a low flame (to avoid spat- tering) until the contents are thoroughly charred, place the dish in an electric muffle, preferably with pyrometer attached, and ignite to a white ash at a tem- perature not greater than 500°C. (900°F.). Cool and weigh. Express the result as grams per 100 cc. Results below 0.715 gram per 100 cc. indicate added water. Multiply by the factor 1.021 (dilution of the acetic serum being 2%) to obtain the result on the sour serum ash. 1 7 SOUR SERUM.— TENTATIVE. (a) Zeiss immersion refractometer reading. — Allow the milk to sour spontane- ously, filter and determine the immersion refractometer reading of the clear serum at 20°C. A reading below 38.3 indicates added water. (b) ^s/i^— Determine the ash in 25 cc. of the serum, obtained in (a), as directed in 16 (b). Results below 0.730 gram per 100 cc. indicate added water. 18 ZEISS REFRACTOMETER READING OF COPPER SERUM.— TENTATIVE. To 1 volume of copper sulphate solution (72.5 grams of copper sulphate per liter, adjusted if necessary to read 36 at 20°C. on the scale of the Zeiss immersion refractometer, or, to a specific gravity of 1.0443 at ^^) add 4 volumes of milk. • Shake well and filter. Determine the Zeiss refractometer reading of the clear serum at 20°C. A reading below 36 indicates added water. GELATIN, 19 Qualitative Test. — Tentative. To 10 cc. of the milk add an equal volume of acid mercuric nitrate solution (mer- cury dissolved in twice its weight of nitric acid (sp. gr. 1.42) and this solution diluted to 25 times its volume with water), shake the mixture, add 20 cc. of water, shake again, allow to stand 5 minutes and filter. If much gelatin is present, the filtrate will be opalescent and cannot be obtained quite clear. To a portion of the filtrate contained in a test tube, add an equal volume of saturated aqueous picric acid solution. A yellow precipitate will be produced in the presence of any con- siderable amount of gelatin, while smaller amounts will be indicated by a cloudi- ness. In the absence of gelatin the filtrate will remain perfectly clear. 20 PRESERVATIVES.— TENTATIVE. Proceed as directed under X. To test for salicylic or benzoic acid acidify 100 cc. of the milk with 5 cc. of hydrochloric acid (1 to 3), shake until curdled, filter and treat the clear filtrate as directed under X, 2, 3 or 8. 292 METHODS OF ANALYSIS [Chap. To test for formaldehyde proceed as directed under X, 17, 18, 19, 20, 21, 22, or 23, applying the test directly to the milk. COLORING MATTERS. 21 Leach Method. — Tentative. Warm about 150 cc. of milk in a casserole over a flame and add about 5 cc. of acetic acid, then slowly continue the heating nearly to the boiling point while stir- ring. Gather the curd, when possible, into one mass with a stirring rod and pour off the whey. If the curd breaks up into small flecks, separate from the whey by straining through a sieve or colander. Press the curd free from adhering liquid, transfer to a small flask and macerate for several hours, preferably overnight, in about 50 cc. of ether, the flask being tightly corked and shaken at intervals. De- cant the ether extract into an evaporating dish, remove the ether by evaporation and test the fatty residue for annatto as directed in XI, 24. The curd of an uncoloredmilk is perfectly white after complete extraction with ether, as is also that of a milk colored with annatto. If the extracted fat-free curd is distinctly colored an orange or yellowish color, a coal tar dye is indicated. In many cases upon treating a lump of a fat-free curd in a test tube with a little strong hydrochloric acid the color changes to pink, indicating the presence of a dye simi- lar to aniline yellow or butter yellow or perhaps one of the acid azo yellows or oranges. In such cases, separate and identify the coloring matter present in the curd as directed under XI. If aniline yellow, butter yellow, or other oil-soluble •dye is present, the greater part will be found in the ether extract containing the fat. In such cases proceed as directed under XI, 3. In some cases the presence of coal tar dyes can be detected by treating about 10 cc. of the milk directly with an equal volume of hydrochloric acid (sp. gr. 1.20) in a porcelain casserole, giving the dish a slight rotary motion. In the presence of some dyes the separated curd acquires a pink coloration. CREAM. 22 SOLIDS.-OFFICIAL. Proceed as directed in 1 , employing 2-3 grams of the sample. 23 ASH.— OFFICIAL. Proceed as directed under 2. 24 TOTAL NITROGEN.-OFFICIAL. Proceed as directed under 3. LACTOSE. 25 Gravimetric Method. — Official. Proceed as directed under 1 1 . FAT. 26 Extraction Method. — Official. Weigh 4-5 grams of the homogeneous sample into a Rohrig tube or similar appa- ratus, dilute with water to about 10.5 cc. and proceed as directed under 12. 27 Babcock Method. — Official. Weigh 9 or 18 grams, depending upon the fat content of the sample, into a stand- ard Babcock cream bottle and proceed as directed under 15. XXII] DAIRY PRODUCTS 293 28 GELATIN.-TENTATIVE. Proceed as directed under 19. 29 COLORING MATTERS.— TENTATIVE. Proceed as directed under XI, particularly 3 and 24 for the detection of oil- soluble coal tar dyes and annatto. 30 PRESERVATIVES.-TENTATIVE. Proceed as directed under X. 31 CONDENSED MILK (UNSWEETENED). Dilute 40 grams of the homogeneous sample with 60 grams of water and pro- ceed as directed under 1 to 15, inclusive, 19, 20 and 21, correcting the results for the dilution. CONDENSED MILK (SWEETENED). 32 PREPARATION OF SAMPLE.-OFFICIAL. If cold, place the can in water at 30°-35°C. until warm. Open, scrape out all milk adhering to the interior of the can and mix by transferring the contents to a dish sufficiently large to stir thoroughly and make the whole mass homogeneous. Weigh 100 grams into a 500 cc. flask and make up to the mark with water. If the milk will not dissolve completelj', weigh out each portion for analysis separately. 33 TOTAL SOLIDS.-OFFICIAL. Use 10 cc. of the solution, prepared as directed in 32, and proceed as directed in 1 , drying either on sand or asbestos fiber. 34 ASH.— OFFICIAL. Evaporate 10 cc. of the solution, prepared as directed in 32, to dryness on a water bath and ignite the residue as directed under VIII, 4. 35 PROTEIN.— OFFICIAL. Determine nitrogen as directed under I, 18, 21 or 23, using 10 cc. of the solu- tion, prepared as directed in 32, without evaporation and multiply by 6.38. 38 LACTOSE.-OFFICIAL. Dilute 100 cc. of the solution, prepared as directed in 32, in a 250 cc. flask to about 200 cc, add 6 cc. of Fehling's copper sulphate solution [VIII, 19 (a)] and make up to the mark. Filter through a dry filter and determine lactose as directed in VIII, 46 or 48. 37 FAT OR ETHER EXTRACT. Roese-Gottlieb Method.— Official. Weigh 4-5 grams of the homogeneous sample into a Rohrig tube or some similar apparatus, dilute with water to about 10.5 cc. and proceed as directed under 12. 38 SUCROSE.-TENTATIVE. Determine sucrose by difference, deducting the milk solids (lactose, protein, fat and ash) from the total solids. 294 METHODS OF ANALYSIS [Chap. BUTTER AND ITS SUBSTITUTES. 39 PREPARATION OF SAMPLE.-OFFICIAL. If large quantities of butter are to be sampled, use a butter trier or sampler. Melt completely the portions thus drawn, 100-500 grams, in a closed vessel at as low a temperature as possible. When softened, cool and, at the same time, shake the mass violently until it is homogeneous and solidified sufficiently to prevent the separation of the water and fat. Then pour a portion into the vessel from which it is to be weighed. The sample should completely or nearly fill the vessel and should be kept in a cool place until analyzed. 40 MOISTURE.— OFFICIAL. Weigh 1.5-2.5 grams of the sample into a flat-bottomed dish, having a surface of at least 20 sq. cm., dry at the temperature of boiling water and weigh at hourly intervals until the weight becomes constant. The use of clean, dry sand or asbestos is admissible. ETHER EXTRACT. 41 Indirect Method. — Official. Dissolve the dry butter, obtained in the moisture determination in which no absorbent was used, in absolute ether or petroleum ether, transfer to a weighed Gooch, with the aid of a wash bottle filled with the solvent and wash until free from fat. Dry the Gooch and contents at the temperature of boiling water until the weight is constant and determine the fat. 42 Direct Method.— Official. From the dry butter, obtained in the determination of moisture, either with or without the use of an absorbent, extract the fat with anhydrous, alcohol-free ether, receiving the solution in a weighed flask. Evaporate the ether, dry the extract at the temperature of boiling water and weigh at hourly intervals until the weight is constant. 43 CASEIN, ASH AND CHLORIN.— OFFICIAL. Cover the crucible, containing the residue from the fat determination by the indirect method, 41, and heat gently at first, then raise the temperature gradually to just below redness. The cover may then be removed and heating continued until the contents of the crucible are white. The loss in weight represents casein, and the residue in the crucible, mineral matter. Dissolve this mineral matter in water slightly acidified with nitric acid and determine chlorin, either gravimetri- cally as directed under I, 16 (a), or volumetrically as directed under III, 15. 44 SALT.-OFFICIAL. Weigh in a counterpoised beaker 5-10 grams of butter, using portions of about 1 gram from different parts of the sample. Add about 20 cc. of hot water and, after the butter is melted, transfer the whole to a separatory funnel. Insert the stopper and shake for a few moments. Let stand until all the fat has collected on the top of the water, then draw off the latter into a flask, being careful to let none of the fat globules pass. Again add hot water, rinsing the beaker, and repeat the extrac- tion 10-15 times, using 10-20 cc. of water each time. The washings will contain all but a mere trace of the sodium chlorid originally present in the butter. Determine the amount in the whole or an aliquot of the liquid by titration with standard silver nitrate, using potassium chromate as an indicator. xxii] dairy products 295 Fat. 45 preparation of sample.— official. Melt the butter and keep in a dry place at about 60°C. for 2-3 hours or until the water and curd have entirely separated. Filter the clear, supernatant fat through a dry filter paper in a hot water funnel or in an oven at about 60°C. If the filtered liquid fat is not perfectly clear, refilter. 46 EXAMINATION. Proceed as directed under XXIII. 47 Microscopic Method. — Official. Place on a slide a small portion of the fresh, unmelted sample taken from the inside of the mass, add a drop of pure olive oil, apply a cover-glass with gentle pressure, and examine with a magnification of 120-150 diameters for crystals of lard, etc. Examine the same specimen with polarized light and a selenite plate without the use of oil. Pure fresh butter will show neither crystals nor a parti- colored field with selenite. Renovated butter or other fats melted and cooled and mixed with butter will usually present crystals and variegated colors with the selenite plate. For further microscopic study dissolve in a test tube 3-^ cc. of the fat in 15 cc. of ether. Close the tube with a loose plug of cotton wool and allow to stand 12-24 hours at 20°-25°C. When crystals form at the bottom of the tube, remove with a pipette, glass rod or tube, place on a slide, cover and examine under a microscope. The crystals formed by later deposits may be examined in a similar way. Com- pare with crystals obtained in the same way from samples of known purity. 48 PRESERVATIVES.— TENTATIVE. Proceed as directed under X. 49 COLORING MATTERS.— TENTATIATE. Pour about 2 grams of the filtered fat, dissolved in ether, into each of 2 test tubes. Into one of the tubes pour 1-2 cc. of hydrochloric acid and into the other about the same volume of dilute potassium hydroxid solution. Shake the tubes well and allow to stand. In the presence of azo dyes the test tube to which the acid has been added will show a pink to wine-red coloration, while the potash solution in the other tube will show no color. If, on the other hand, annatto or other vegetable color has been used, the potash solution will be colored yellow, while no color will be apparent in the acid solution. General test. — Proceed as directed under XI, particularly 3 and 24, for the detec- tion of oil-soluble coloring matters and annatto. RENOVATED BUTTER AND OLEOMARGARINE. 50 Foam Test.— Tentative. Heat 2-3 grams of the sample, either in a spoon or dish, over a free flame. True butter will foam abundalitly, whereas process butter will bump and sputter, like hot grease, without foaming. Oleomargarine behaves like process butter, but chemical tests will determine whether the sample is oleomargarine or butter. 296 METHODS OF ANALYSIS [Chap. 51 Melted Fat Test.— Tentative. Melt 50-100 grams of butter or renovated butter at 50°C. The curd from butter will settle, leaving a clear supernatant fat; in the case of renovated butter, the supernatant fat remains more or less turbid. CHEESE. 52 SELECTION AND PREPARATION OF THE SAMPLE.— OFFICIAL. When the cheese can be cut, take a narrow, wedge-shaped segment reaching from the outer edge to the center of the cheese. Cut this into strips and pass 3 times through a sausage machine. When the cheese cannot be cut, take the sample with a cheese trier. If only 1 plug can be obtained, take it perpendicular to the surface of the cheese at a point one third the distance from the edge to the center and extending either entirely or half way through it. When possible, draw 3 plugs, 1 from the center, 1 from a point near the outer edge, and 1 from a point half way between the other 2. For inspection purposes reject the rind but for investigations requiring the absolute amount of fat in the cheese include the rind in the sample. Either grind the plugs in a sausage machine or cut them very finely and mix carefully, preferably the former. 53 MOISTURE.— TENTATIVE. Place 2-3 grams of very short fiber asbestos (the long fiber may be made suit- able by rubbing it through a fine sieve) in a flat-bottomed platinum dish, 6-7 cm. in diameter, and press the asbestos down firmly. Place in the dish a glass rod, about 5 mm. in diameter and slightly longer than the diameter of the dish. Ignite, cool and weigh the dish and contents. Then weigh into the dish 4-5 grams of the sample, prepared as directed under 52, and mix the cheese and asbestos intimately with the glass rod until the mass is homogeneous. Leave the mass in as loose a con- dition as possible to facilitate the drying. Dry the mixture in an oven at 100°C. and weigh at 1-1| hour intervals until the weight becomes constant (3 weighings are usually sufficient). 54 ASH AND SALT.-OFFICLAX. The dry residue from the moisture determination may be used for the determi- nation of ash. If the cheese be rich in fat, the asbestos will be saturated with it. Ignite cautiously to avoid spattering and remove the lamp while the fat is burn- ing off. When the flame has died out, complete the burning in a muffle at low red- ness. When desired, the salt may be determined in the ash, as directed in 43. 55 NITROGEN.— OFFICIAL. Determine nitrogen as directed under I, 18, 21 or 23, using about 2 grams of cheese, and multiply the percentage of nitrogen by 6.38 to obtain the per cent of nitrogen compounds. 55 ACIDITY.— TENTATIVE. To 10 grams of finely divided cheese add water at a temperature of 40°C. until the volume equals 105 cc, shake vigorously and filter. Titrate 25 cc. portions of the filtrate, representing 2.5 grams of the sample, with standard sodium hydroxid, preferably N/10, using phenolphthalein as an indicator. Express the result in terms of lactic acid. XXII] DAIRY PRODUCTS 297 57 COLORING MATTERS.-TENTATIVE. Proceed as directed under XI. FAT. 58 PREPARATION OF SAMPLE.— TENTATIVE. (a) Alkaline extraction. — Treat about 300 grams of the cheese, cut into frag- ments the size of a pea, with 700 cc. of 5% potassium hydroxid solution at 20°C. in a large, wide-necked flask, shaking vigorously to dissolve the casein. In 5-10 minutes the casein will be dissolved and the fat will rise to the surface in lumps. Collect the lumps of fat into as large a mass as possible by shaking gently. Pour cold water into the flask until the fat is driven up into the neck and remove it by suitable means. Wash the fat thus obtained with just sufficient water to remove the residue of the alkali which it may contain. The fat is not perceptibly attacked by the alkali in this treatment, is practically all separated in a short time and is then easily prepared for chemical analysis by filtering and drying as directed in 45. (b) Acid extraction. — Pass the cheese through a grinding machine, transfer to a large flask and cover with warm water, using 1 cc. for every gram of cheese. Shake thoroughly and add sulphuric acid (sp. gr. 1.82-1.825) slowly and in small quanti- ties, shaking after each addition of acid. The total amount of acid used should be the same as the amount of water employed. Remove the fat, which separates after standing a few minutes, by means of a separatory funnel, wash free from acid, filter and dry as directed in 45. 59 EXAMINATION.— TENTATIVE, Proceed as directed under XXIII. Estimation. 60 Gravimetric Method. — Official. Cover the perforations in the bottom of an extraction tube with dry asbestos felt, and place on this a mixture containing equal parts of anhydrous copper sul- phate and pure, dry sand to a depth of about 5 cm., packing loosely. Cover the upper surface of this material with a layer of asbestos. Place on this 2-n5 grams of the sample and extract with anhydrous ether for 5 hours in a continuous extrac- tion apparatus. Remove the cheese and grind it with pure sand in a mortar to a fine powder, return the mixed cheese and sand to the extraction tube, wash the mor- tar with ether, add the washings to the tube and continue the extraction for at least 10 hours. 61 Schmidt-Bondzynski Method, Modified. — Tentative. Rub up, by means of a glass rod, 1 gram of the homogeneous sample with 9 cc. of water and 1 cc. of concentrated ammonium hydroxid in a narrow 100-125 cc. beaker. Digest the mixture at a low heat until the casein is well softened; neutralize with concentrated hydrochloric acid, using litmus as an indicator and add 10 cc. more of concentrated hydrochloric acid. Add a pinch of sand to prevent bmnping and boil gently for 5 minutes, keeping the beaker covered with a watch glass. Cool the solution, transfer to .a Rohrig tube or some similar apparatus, rinse the beaker with 25 cc. of washed ethyl ether and shake well. Add 25 cc. of redistilled petro- leum ether (b. p. below 65°C.), let the solutions separate and proceed from this point as directed in 12. 298 METHODS OF ANALYSIS 62 Babcock Method. — Tentative. Weigh about 6 grams of the cheese in a tared dish. Add 10 cc. of boiling water and stir with a rod until the cheese softens and an even emulsion is formed, preferably adding a few drops of strong ammonium hydroxid, and keep the beaker in hot water until the emulsion is nearly completed and the mass free from lumps. If the sample is a whole milk cheese, employ a Babcock cream bottle. After cooling, transfer the contents of the beaker to the test bottle by adding to the beaker about half of the 17.6 cc. of sulphuric acid usually employed in this test, stirring with a rod, and pouring carefully into the bottle, using the remainder of the acid in 2 portions for washing out the beaker. Then proceed as directed in 15. Multiply the fat reading by 18 and divide by the weight of the sample taken to obtain the per cent of fat. BIBLIOGRAPHY. 1 Browne. Handbook of Sugar Analysis. 1912, p. 252. 2 Z. Nahr. Genussm., 1905, 9: 531. 3 Farrington and WoU. Testing Milk and Its Products. 23rd ed., 1916. *Van Slyke. Modern Methods of Testing Milk and Milk Products. Rev. ed.. 1907. sChem.. Ztg., 1908, 32:617. XXIII. FATS AND OILS. 1 PREPARATION OF SAMPLE.— OFFICIAL. Melt solid fats and filter by means of a hot water funnel or similar apparatus. Make the different determinations on samples of this melted, homogeneous mass. Filter oils that are not clear. Keep oils and fats in a cool place and protected from light and air, otherwise they will soon become rancid. Weigh out at one time as many portions as are needed for the various determinations, using a small beaker or weighing burette. SPECIFIC GRAVITY. . 20°C. ^ . .. 20 °C Determine the specific gravity of the oil at -^ by means of a pycnometer. If the specific gravity of the oil is determined at other than standard tempera- ture, the approximate specific gravity at 20°C. may be calculated by means of the following formula: G = G' + 0.0007 (T-20°C.) in which G = specific gravity at 20°C.; T°C G' = specific gravity at -^ ; T = temperature at which the specific gravity was determined; 0.0007 = mean correction' for 1°C. At the Temperature of Boiling Water.— OflBciaL 3 STANDARDIZATION OF FLASKS. (a) Fill a tared, 25-30 cc. specific gravity flask with freshly boiled, hot water. Place in a briskly boiling water bath for 30 minutes, replacing any evaporation from the flask by the addition of boiling water. Then insert the stopper, previous- ly heated to 100°C., remove the flask, cool and weigh. (b) The following formula may be used for calculating the weight of water (W^) which a given flask will hold at T° (weighed in air with brass weights at the tempera- ture of the room) from the weight of water (W*^) (weighed in air with brass weights at the temperature of the room) contained therein at t°: W^ = W* ^ [1 + 0.000026 (T - t)] in which d' d'^ = the density of water at T°; d* = the density of water at t°. 4 DETER.MINATION. Fill the flask, dried at the temperature of boiling water, with the dry, hot, freshly filtered fat, which should be entirely free from air bubbles; keep in the water bath 30 minutes at the temperature of boiling water. Insert the stopper, previously heated to 100°C., cool and weigh. Divide the weight of contained fat by the weight of contained water previously found to obtain the specific gravity. The weight of water at boiling temperature must be determined under the baro- metric conditions prevailing at the time the determination is made. 299 300 METHODS OF ANALYSIS [Chap. INDEX OF REFRACTION. 5 General Directions.— Tentative. Place the instrument in such a position that diffuse daylight or any form of arti- ficial light can readily be obtained for illumination. Circulate through the prisms a stream of water of constant temperature. Determine the index of refraction with any standard instrument, reading oils at 20°C. and fats at 40°C. The readings of the Zeiss butyro-refractometer can be reduced to standard tem- perature by the following formula^: R = R' 4- 0.55 (T' - T) in which R = the reading reduced to temperature T; R' = the reading at T'C. T' = the temperature at which reading R' is made; T = the standard temperature; 0.55 = correction in scale divisions for 1°C. With oils the factor 0.58 is substituted in the formula for 0.55, since they have a higher index of refraction. The readings of instruments, which give the index of refraction directly, can be reduced to standard temperature by substituting the factor 0.000365 for 0.55 in the formula. As the temperature rises the refractive index falls. The instrument used may be standardized with water at 20°C., the theoretical refractive index of water at that temperature being 1.3330. Any correction found should be made on all readings. The index of refraction varies directly with the specific gravity. If the results appear abnormal, compare the specific refractive power^ with the normal. Calcu- N - 1 late the specific refractive power from the formula — — , in which N equals the refractive index and D the specific gravity. According to Procter* the Lorenz N2-1 N-1 formula gives much more satisfactory results than — — — . g By Means of the Abbe Refractometer.— Official. To charge the instrument, open the double prism by means of the screw head and place a few drops of the sample on the prism or, if preferred, open the prisms slightly by turning the screw head and pour a few drops of the sample into the funnel-shaped aperture between the prisms. Then close the prisms firmly by tightening the screw head. Allow the instrument to stand for a few minutes before the reading is made, so that the temperature of the sample and the instru- ment will be the same. The method of measurement is based upon the observation of the position of the border line of total reflection in relation to the faces of a prism of flint glass. Bring this border line into the field of vision of. the telescope by rotating the double prism by means of the alidade in the following manner: Hold the sector firmly, move the alidade backward or forward until the field of vision is divided into a light and a dark portion. The line dividing these portions is the "border line". This, as a rule, will not be a sharp line but a band of color which is eliminated by rotating the screw head of the compensator until a sharp, colorless line is obtained. The border line should now be adjusted so that it falls on the point of intersection of the 2 cross hairs. Read the refractive index of the substance directly on the scale of the sector. Check the correctness of the instrument, as directed under 5, or by means of the quartz plate which accompanies it, using monobromnaphtha- lene, and make the necessary correction in the reading. xxmi FATS AND OILS 301 7 By Means of the Zeiss Butyro-Refractometer.— Official. Place 2 or 3 drops of the filtered fat on the surface of the lower prism. Close the prisms and adjust the mirror until it gives the sharpest reading. If the reading be indistinct after running water of a constant temperature through the instru- ment for some time, the fat is unevenly distributed on the surfaces of the prism. As the index of refraction is greatly affected by temperature, care must be used to keep the latter constant. The instrument should be carefully adjusted by means of the standard fluid which is supplied with it. Convert the degrees of the instru- ment into refractive indices from 8. 8 Table 20. BtUyro-refractometer readings and indices of refraction. REjVDINO INDEX OF READING INDEX OF READING INDEX OF READING INDEX OF REFRACTION REFRACTION REFRACTION REFRACTION 40.0 1.4524 50.0 1.4593 60,0 1.4659 70.0 1.4723 40.5 1.4527 50.5 1.4596 60,5 1.4662 70.5 1.4726 41.0 1.4531 51.0 1.4600 61.0 1.4665 71.0 1.4729 41.5 1.4534 51.5 1.4603 61.5 1.4668 71.5 1.4732 42.0 1,4538 52.0 1.4607 62.0 1.4672 72.0 1.4735 42.5 1.4541 52.5 1.4610 62.5 1.4675 72.5 1.4738 43.0 1.4545 53.0 1.4613 63.0 1.4678 73.0 1.4741 43.5 1.4.548 53.5 1.4616 63.5 1.4681 73.5 1.4744 44.0 1.4552 54.0 1.4619 64.0 1.4685 74.0 1.4747 44.5 1.4555 54.5 1.4623 64.5 1.4688 74.5 1.4750 45.0 1.4558 55.0 1.4626 65.0 1.4691 75.0 1.4753 45.5 1.4562 55.5 1.4629 65.5 1.4694 75.5 1.4756 46.0 1.4565 56.0 1.4633 66.0 1.4697 76.0 1.4759 46.5 1.4569 56.5 1.4636 66.5 1.4700 76.5 1.4762 47.0 1.4572 57.0 1.4639 67.0 1,4704 77.0 1.4765 47.5 1.4576 57.5 1.4642 67.5 1.4707 77.5 1.4768 48.0 1.4579 58.0 1.4646 68.0 1.4710 78.0 1.4771 48.5 1.4583 58.5 1.46^19 68.5 1.4713 78.5 1.4774 49.0 1.4586 59.0 1.4652 69.0 1.4717 79.0 1.4777 49.5 1.4590 59.5 1.4656 69.5 1.4720 79.5 1.4780 MELTING POINT OF FATS AND FATTY ACIDS. Wiley Method. — Official. Alcohol-water mixture. — Specific gravity same as that of the fat to be examined. Prepare by boiling, separately, water and 95% alcohol by volume for 10 minutes to remove the gases which may be held in solution. While still hot pour the water into the test tube until it is almost half full. Nearly fill the test tube with the hot alcohol, poured down the side of the inclined tube to avoid too much mi.xing. If the alcohol be added after the water has cooled, the mixture will contain so many air bubbles as to be unfit for use. 10 , DETERMINATION. Prepare disks of fat as follows: Allow the melted and filtered fat to fall a distance of 15-20 cm. from a dropping tube upon a piece of ice or upon the surface of cold mercury. The disks thus formed should be 1-1.5 cm. in diameter and weigh about 302 METHODS OF ANALYSIS [Chap. 200 mg. When solid remove the disk and allow to stand 2-3 hours in order to obtain the normal melting point. Place a test tube, 30 by 3.5 cm., containing the alcohol-water mixture, in a tall beaker, 35 by 10 cm., containing ice and water, until cold. Then drop the disk of fat into the tube and it will at once sink to a point where the density of the alcohol- water mixture is exactly equivalent to its own. Lower an accurate thermometer, which can be read to 0.1°C., into the test tube until the bulb is just above the disk. In order to secure an even temperature in all parts of the alcohol-water mixture around the disk, stir gently with the thermometer. Slowly heat the water in the beaker, constantly stirring it by means of an air blast or other suitable device. When the temperature of the alcohol-water mixture rises to about 6°C. below the melting point of the fat, the disk of fat begins to shrivel and gradually rolls up into an irregular mass. Lower the thermometer until the fat particle is even with the center of the bulb. Rotate the thermometer bulb gently and regulate the temperature so that about 10 minutes for the increment of the last 2°C. are required. As soon as the fat mass becomes spherical, read the thermometer. Remove the tube from the bath and again cool. Place in the bath a second tube containing the alcohol-water mixture. The test tube is of sufficiently low tempera- ture to cool the bath to the desired point, ice water having been used for cooling. After the first or preliminary determination, regulate the temperature of the bath so as to reach a maximum of about 1.5°C. above the melting point of the fat under examination. Do not allow the edge of the disk to touch the sides of the tube. If so, make a new determination. Run triplicate determinations of which the second and third results should agree closely. 1 1 Capillary Tube Method^. — Tentative. Draw the melted fat or fatty acids into a thin-walled capillary tube. Use a column of fat 1-2 cm. long, according to the length of the thermometer bulb. Seal 1 end of the tube and cool on ice 12-15 hours. Attach the capillary tube to the bulb of an accurate thermometer, graduated to 0.2°C., immerse in a large test tube of water surrounded by a beaker of water and heat very slowly. An apparatus similar to that indicated in Fig. 12 may be used. The temperature at which the substance becomes transparent is taken as the melting point. TITER TEST. Alcoholic or Aqueous Sodium Hydroxid Method. — Tentative. 12 APPARATUS. Standard thermometer. — The thermometer must have a zero mark, 0.1° gradua- tions between 10°-60°C., and auxiliary reservoirs at the upper end and between the 0° and the 10° marks. The cavity in the capillary tube between the 0° and the 10° marks must be at least 1 cm. below the 10° mark, which must be about 3-4 cm. above the bulb, the total length of the thermometer being about 38 cm. The bulb should be about 3 cm. long and 6 mm. in diameter. The stem of the thermometer should be 6 mm. in diameter and made of the best thermometer tubing, with scale etched on the stem, the graduation to be clear cut and distinct. The thermometer should have been annealed for 75 hours at 450°C., and the bulb should be of Jena normal 16'" glass, moderately thin, so that the thermometer will be quick-acting. FATS AND OILS DETERMINATION. 303 XXIII] 13 Saponify 75 grams of the sample in a metal dish with 60 cc. of 30% sodium hy- droxid solution (36° Baum6) and 75 cc. of 95% alcohol by volume or 120 cc. of water. Evaporate to dryness over a very low flame or on an iron or asbestos plate, stirring constantly. Dissolve the dry soap in a liter of boiling water and, if alcohol has been used, boil for 40 minutes to remove it, adding sufficient water to replace that lost in boiling. Liberate the fatty acids by adding 100 cc. of 30% sulphuric FIG. 12. APPARATUS FOR THE MELTING POINT DETERMINATION. acid (25° Baum6) and boil until they form a clear, transparent layer. AVash with boiling water until free from sulphuric acid, collect in a small beaker and place on a steam bath until the water has settled and the fatty acids are clear; then decant into a dry beaker, filter while hot and dry 20 minutes at 100°C. When dried, cool the fatty acids to 15°-20°C. above the expected titer and transfer to the titer tube, 25 by 100 mm. (1 by 4 inches) and made of glass about 1 mm. in thickness. Place in a 16 ounce wide-mouthed bottle of clear glass, 70 by 150 mm. (2.8 by 6 304 METHODS OF ANALYSIS [Chap. inches), fitted with a perforated cork, so as to hold the tube rigidly when in position. Suspend the standard thermometer so that it can be used as a stirrer, and stir the mass slowly until the mercury remains stationary for 30 seconds. Then allow the thermometer to hang quietly, with the bulb in the center of the mass, and observe the rise of the mercury column. The highest point to which it rises is regarded as the titer of the fatty acids. Test the fatty acids for complete saponification as follows: Place 3 cc. in a test tube and add 15 cc. of 95% alcohol by volume. Bring the mixture to a boil and add an equal volume of ammonium hydroxid (sp. gr. 0.96). A clear solution should result. The titer must be made at about 20°C. for all fata having a titer above 30°C., and at 10°C. below the titer for all other fats. 14 Glycerol-Potassium Hydroxid Method. — Tentative. Heat 75 cc. of glycerol-potassium hydroxid solution (25 grams of potassium hy- droxid in 100 cc. of high-test glycerol) to 150°C. in an 800 cc. beaker; then add 50 cc. of the oil or melted fat, previously filtered if necessary to remove foreign substances. Saponification often takes place almost immediately, but heating, with frequent stirring, should be continued for 15 minutes, avoiding a temperature much above 150°C. When the saponification is complete, as indicated by the perfectly homo- geneous solution, pour the soap into an 800 cc. casserole containing about 500 cc. of nearly boiling water, add carefully 50 cc. of 30% sulphuric acid and heat the solution, with frequent stirring, until the layer of fatty acids separates out perfectly clear. Transfer the fatty acids to a tall separatory funnel, wash 3-4 times with boiling water to remove all mineral acids, draw the fatty acids off into a small beaker, and allow to stand on a steam bath until the water has settled out and the acids are clear. Filter into a dry beaker and heat to 150°C. on a thin asbestos plate, stirring continually with the thermometer, transfer to a titer tube, fill it to within 2.5 cm. of the top and take the titer as directed in 13. lODIN ABSORPTION NUMBER. Hubl Method.— Official. 15 REAGENTS. (a) Htibl's iodin solution. — Dissolve 26 grams of pure iodin in 500 cc. of 95% alco- hol by volume. Dissolve 30 grams of mercuric chlorid in 500 cc. of 95% alcohol by volume. Filter the latter solution, if necessary, and mix the 2 solutions. Let the mixed solution stand 12 hours before using. The solution loses strength with age, but can be used so long as 35 cc. of N/10 thiosulphate are equivalent to 25 cc. of the iodin solution. (b) N/10 sodium thiosulphate. — Standardize this solution as follows: Place in a glass-stoppered flask 20 cc. of the N/10 potassium dichromate and 10 cc. of the 15% potassium iodid solution. Add 5 cc. of strong hydrochloric acid. Dilute with 100 cc. of water and allow the N/10 sodium thiosulphate to flow slowly into the flask until the yellow color of the liquid has almost disappeared, add a few drops of the starch indicator and, with constant shaking, continue to add the N/10 sodium thio- sulphate until the blue color just disappears. (C) Starch indicator. — Prepare as directed under VII, 3 (a). (d) 15% potassium iodid solution. (e) N/10 potassium dichromate. — The dichromate solution should be checked against pure iron. XXIII] FATS AND OILS 305 16 DETERMINATION. Weigh about 0.500 gram of fat, or 0.250 gram of oil (0.100-0.200 gram in the case of drying oils which have a very high absorbent power), into a 500 cc. glass-stoppered flask or bottle. Dissolve the fat or oil in 10 cc. of chloroform. Add 30 cc. of the HiJbl iodin solution in the case of fats, or 40-50 cc. in the case of oils. Place the bottle in a dark place and allow to stand for 3 hours, shaking occasionally. This time must be adhered to closely in order to obtain good results. The time allowed does not give the complete iodin absorption power of an oil or fat and can not be compared with determinations in which 6-12 hours have been used. It gives very satisfactory comparative results, but the time factor must be closely observed. The excess of iodin should be at least as much as is absorbed. Add 20 cc. of the 15% potassium iodid solution, shake thoroughly and then add 100 cc. of water, wash- ing down any free iodin that may be found on the stopper. Titrate the iodin with the N/10 sodium thiosulphate, adding the latter gradually, with constant shaking, until the yellow color of the solution has almost disappeared. Add a few drops of the starch indicator and continue the titration until the blue color has entirely disappeared. Toward the end of the titration, stopper the bottle and shake vio- lently, so that any iodin remaining in solution in the chloroform may be taken up by the potassium iodid solution. Conduct 2 blank determinations along with that on the sample. The number of cc. of the N/10 sodium thiosulphate required by the blank less the amount used in the determination gives the thiosulphate equivalent of the iodin absorbed by the fat or oil. Ascertain the iodin number by calculating the per cent by weight of iodin absorbed. Haniis Method. — Official. 17 REAGENTS. Hanus' iodin solution. — Dissolve 13.2 grams of iodin in 1 liter of glacial acetic acid (99.5%) which shows no reduction with dichromate and sulphuric acid. Add enough bromin to double the halogen content as determined by titration (3 cc. of bromin are about the proper amount). The iodin may be dissolved by heating but the solution should be cold when the bromin is added. A convenient way to prepare the Hanus solution is as follows: Measure 825 cc. of acetic acid which has shown no reduction by the dichromate test and dissolve in it 13.615 grams of iodin with the aid of heat. Cool and titrate 25 cc. of this solu- tion against the N/10 sodium thiosulphate. Add 3 cc. of bromin to 200 cc. of acetic acid and titrate 5 cc. of the solution against the N/10 sodium thiosulphate. Cal- culate the quantity of bromin solution required exactly to double the halogen con- tent of the remaining 800 cc. of iodin solution as follows: A = p in which A = cc. of bromin solution required; B = 800 X the thiosulphate equivalent of 1 cc. of iodin solution; C = the thiosulphate equivalent of 1 cc. of bromin solution. Example: 136.15 grams of iodin are dissolved in S2.50 cc. of acetic acid. 30 cc. of bromin are dissolved in 2000 cc. of acetic acid. Titrating 50 cc. of the iodin solution against the standard thiosulphate shows that 1 cc. of the iodin solution equals 1.1 cc. of the thiosulphate (0.01G5 gram of iodin). Titrating 5 cc. of the bro- min solution shows that 1 cc. of the bromin solution equals 4.6 cc. of the thiosulphate. Then the quantity of bromin solution required to double the halogen content of 8200 X 1 1 the remaining 8200 cc. of iodin solution is equivalent to . „ — '— or 1961 cc. Upon 306 METHODS OF ANALYSIS [Chap. mixing the 2 solutions in this proportion, a total volume of 10161 cc is obtained, containing 135.3 grams of iodin. In order to reduce this solution to the proper strength (13.2 grams iodin per liter), 10.161X13.2 = 134.1; 135.3- 134.1 = 1.2] 1 2 X 1000 of iodin present in excess, or — = 91 cc. of acetic acid which must be added. The other reagents used are described under 15. 18 DETERMINATION. Weigh about 0.500 gram of fat, or 0.250 gram of oil (0.100-0.200 gram in the case of drying oils which have a very high absorbent power), into a 500 cc. glass-stoppered flask or bottle. Dissolve the fat, or oil, in 10 cc. of chloroform, add 25 cc. of the Hanus iodin solution and allow to stand for 30 minutes, shaking occasionally, The excess of iodin should be at least 60% of the amount added. Add 10 cc. of the 15% potassium iodid solution and continue as directed under 16. SAPONIFICATION NUMBER (KOETTSTORFER NUMBER).-OFFICIAL. 1 REAGENTS. (a) N 1% hydrochloric acid. — Prepare as directed under I, 16 (a). (b) Alcoholic potassium hijdroxid solution. — Dissolve 40 grams of the purest potassium hydroxid in 1 liter of 95% redistilled alcohol by volume. The alcohol should be redistilled from potassium hydroxid over which it has been standing for some time, or with which it has been boiled for some time using a reflux condenser. The solution must be clear and the potassium hydroxid free from carbonates. 20 DETERMINATION. Weigh accurately about 5 grams of the filtered sample into a 250-300 cc. Erlen- meyer flask. Pipette 50 cc. of the alcoholic potassium hydro.xid solution into the flask, allowing the pipette to drain for a definite time. Connect the flask with an air condenser and boil until the fat is completely saponified (about 30 minutes). Cool and titrate with the N/2 hydrochloric acid, using phenolphthalein as an indi- cator. Calculate the Koettstorfer number (mg. of potassium hydroxid required to saponify 1 gram of fat). Conduct 2 or 3 blank determinations, using the same pipette and draining for the same length of time as above. 21 SOLUBLE ACIDS.-OFFICIAL. Place the flask, used in 20, on a water bath and evaporate the alcohol. Add such an amount of N/2 hydrochloric acid that its volume plus the amount used in titrat- ing for the saponification number will be 1 cc. in excess of the amount required to neutralize the 50 cc. of the alcoholic potassium hydroxid solution added, and place on the steam bath until the separated fatty acids form a clear layer on the upper surface of the liquid. Fill to the neck with hot water and cool in ice water until the cake of fatty acids is thoroughly hardened. Pour the liquid contents of the flask through a filter into a liter flask. Fill the flask again with hot water, set on the steam bath until the fatty acids collect at the surface, cool by immersing in ice water, and again filter the liquid into the liter flask. Repeat this treatment with hot water 3 times, cooling and collecting the washings in the liter flask after each treatment. Titrate the combined washings with N/10 alkali, using phenolphthalein as an indicator. Subtract 5 (corresponding to the excess of 1 cc. of N/2 acid) from the number of cc. of N/10 alkali used and multiply by 0.0088 to obtain the weight of soluble acids as butyric acid. Calculate the percentage of soluble acids. XXIII] FATS AND OILS 307 22 INSOLUBLE ACIDS (HEHNER NUMBER).-OFFICIAL. Allow the flask, containing the cake of insoluble fatty acids from 21 and the paper throuH50.C6ll4XH.COCH3)2HI.l4. (2) The gravimetric determination of acetphenetidin may, if desired, be efi"ected as follows: Filter off the periodid, preferably by suction, wash with 10-15 cc. of the standard iodin solution, then transfer together with the filter to a scparatory funnel, using not over 50 cc. of water. Remove both free and added iodin with a few small crystals of sodium sulphite and extract the liquid with three 50 cc. portions of chloroform, washing each portion subsequently into a second separatory funnel with 5 cc. of water. After washing and clearing, filter the chloroform solution through 356 METHODS OF ANALYSIS [Chap. a dry 5.5 cm. filter into a 200 cc. Erlenmeyer flask, distil off most of the chloro- form, transfer the residual solution (5-10 cc), by means of a little chloroform, to a small, tared beaker or crystallizing dish, evaporate to dryness on a steam bath, cool and weigh. For the identification of acetphenetidin, either alone or in admixture with acet- anilid, the following test will be found of value': To 1-2 mg. of the sample in a test tube add a drop of acetic acid, 0.5 cc. of water and 1 cc. of N/10 iodin, warm the mixture to about 40°C., then add a drop of concentrated hydrochloric acid. If acetphenetidin alone is present, its periodid separates almost immediately in the form of reddish brown leaflets or needle-like crystals. If the sample consists largely of acetanilid, the separation takes place on cooling and shaking the liquid. In the presence of considerable acetanilid, the periodid first separates as minute, oily globules, which, on vigorous shaking, gradually become crystalline. This test is so delicate that as little as 0.5 mg. of acetphenetidin may, if alone, be detected in the form of its characteristic periodid. 13 ACETANILID.-TENTATIVE. (1) If the combined weight of the acetphenetidin-acetanilid mixture is known, determine that of the latter ingredient by difference; or, (2) Determine it directly from a second aliquot of the filtrate from the acetphenetidin periodid in 1 2 as follows : Pipette 25-30 cc. of the clear liquid into a separatory funnel, decolorize with solid sodium sulphite and solid sodium bicarbonate in slight excess, add 1 or 2 drops of acetic anhydrid, then extract with three 60 cc. portions of chloroform, passing the chloroform solution, when cleared, through a small, dry filter into a 200 cc. Erlenmeyer flask, and distil the chloroform, by the aid of gentle heat, to about 20 cc. Add 10 cc. of sulphuric acid (1 to 10) and digest on a steam bath until the resi- due has been reduced one half, add 20 cc. of water and continue the digestion for an hour; then add a second 20 cc. portion of water and 10 cc. of concentrated hydro- chloric acid, titrate very slowly, drop by drop, with the standard bromid-bromate solu- tion, 2 (a), until a faint j^ellow color remains. While adding this reagent, rotate the flask sufficiently to agglomerate the precipitated tribromanilin. Calculate the amount of acetanilid present. If the preparation contains caffein or antipyrin or both in addition to acet- anilid and acetphenetidin, proceed as follows :'(!) Digest the mixture by heating with dilute sulphuric acid to convert acetphenetidin and acetanilid to phenetidin and anilin sulphates, respectively; (2) Separate the caffein and antipyrin by ex- traction with chloroform; (3) Re-form acetphenetidin and acetanilid by treat- ing the solution of the corresponding sulphates with solid sodium bicarbonate in slight excess, then add a few drops of acetic anhydrid and extract with chloroform*. Acetphenetidin CPhenacetin) and Salol in Mixtures^ acetphenetidin. 14 Acid Hydrolysis Method. — Tentative. Weigh out on a tared 5.5 cm. filter" an amount of the sample equal to, or a mul- tiple of, the average weight of a unit dose and wash with suflScient successive, small portions of chloroform to extract completely all acetphenetidin and salol present in the mixture (about 40 cc). Collect the solution in a tared, 100 cc. beaker and evaporate on a warm plate (50°-60°C.) to apparent dryness, using an air blast. Let stand 24 hours at room temperature to practically constant weight, then trans- fer the crystalline residue, by means of chloroform, to a 50 cc. lipped Erlenmeyer flask, evaporate the solvent by means of an air blast and gentle heat, add 10 cc. XXIX] DRUGS 357 of sulphuric acid (1 to 10) and evaporate on the steam bath until the volume is re- duced one half. Add 10 cc. of water and continue the digestion as before, then add a second 10 cc. of water and evaporate to 5 cc. Transfer the residue with about 20 cc. of water to a small separatory funnel and extract with 15, 10 and 5 cc. of chloroform, washing each extract with 5 cc. of water in a second separatory funnel to recover traces of phenetidin sulphate possibly dissolved by the chloroform, finally rejecting the latter since it contains all the salol not previously eliminated during the digestion. Add the wash water in the second separatory funnel to the solution of phenetidin sulphate in the first separatory funnel and proceed as directed under 7, beginning with "Treat with successive small portions of solid sodium bicarbonate". 15 Alkaline Hydrolysis Method. — Tentative. On a small, tared filter weigh out an amount of the sample to contain not more than 0.10 gram of salol, exhaust.with chloroform as directed in 14, collect the sol- vent in a small, lipped Erlenmeyer flask and evaporate the chloroform by means of an air blast without heat. Add 10 cc. of 2.5% sodium hydro.xid solution and heat 5 minutes on a steam bath. Cool quickly to room temperature in running water to prevent partial hydrolysis of the acetphenetidin. Transfer the liquid to a separa- tory funnel with a minimum of water, then rinse out the flask with the first 20 cc. portion of chloroform used in the extraction. Extract the alkaline solution with three 20 cc. portions of chloroform, wash each portion in a second separatory funnel with 5 cc. of water and pass the solution through a small, dry filter into a 200 cc. Erlenmeyer flask. Designate the combined alkaline solution and washings as A. Distil the combined chloroform extracts to about 5 cc. Transfer by means of a little chloroform to a small, tared beaker or crystallizing dish, evaporate on a steam bath with the aid of an air blast, cool and weigh the residual acetphenetidin at intervals until the weight becomes constant. SALOL. 16 Acid Hydrolysis Method. — Tentative. Subtract the weight of acetphenetidin, as determined in 14, from the combined weight of the 2 ingredients determined in 14, to obtain the weight of salol. 1 7 Alkaline Hydrolysis Method. — Tentative. Place the combined alkaline solutions. A, under 15, in a 500 cc. glass-stoppered bottle, dilute with water to about 200 cc, run in from a burette an excess (about 45 cc.) of N/7 potassium bromid-bromate, add 10 cc. of concentrated hydrochloric acid and shake 1 minute, then at inteivals for 30 minutes. Add 10 cc. of 15% potas- sium iodid solution and shake at intervals for 15 minutes. Titrate the free iodin with standard sodium thiosulphate solution (preferably N/7), previously standard- ized against the N/7 bromid-bromate solution. One cc. of N/7 potassium bromid- bromate is equivalent to 2.55 mg. of salol. From the number of cc. of the N/7 bromid-bromate solution used, calculate the amount of salol on the basis of 12 atoms of bromin to 1 molecule of salol. ACETANILID AND SODIUM SALICYLATE IN MIXTURES. 18 PREPARATION OF SAMPLE AND SOLUTION.-TENTATIVE. Weigh an amount of the powdered sample equal to, or a multiple of, an average unit dose, transfer to a separatory funnel containing 10 cc. of water and, for every unit dose, add 0.10 gram of solid sodium bicarbonate. In the case of coated tablets 358 METHODS OF ANALYSIS [Chap. and pills, ascertain their average weight, powder in a mortar and weigh out an amount of the powder equivalent to one or more tablets or pills for each determina- tion prior to treatment in the separatory funnel. In the examination of alcoholic preparations, distil off the alcohol from a measured volume on a steam bath, transfer to a separatory funnel with a minimum of water and add sufficient solid sodium bicarbonate (0.5 to 1.0 gram). 19 ACETANILID.-TENTATIVE. Extract the alkaline solution, obtained under 18, with three 50 cc. portions of chloroform, wash each portion with 5 cc. of water in a second separatory funnel and collect the solvent, without previous drying, in a 200 cc. Erlenmeyer flask. Designate the aqueous solution as A. Distil off the chloroform very gently to about 5 cc, add 10 cc. of dilute sulphuric acid and completely hydrolyze on the steam bath. Proceed from this point as directed in 4. 20 SODIUM SALICYLATE.-TENTATIVE. Acidify the aqueous solution of sodiiun salicylate, A, under 19, with a few drops of concentrated hydrochloric acid and extract with sufficient (3-5) 25 cc. portions of chloroform to exhaust the salicylic acid present in the mixture. Treat each por- tion in a second separatory funnel with 20 cc. of water, containing 1 gram of anhydrous sodium carbonate for every 100 mg. of salicylic acid. Shake vigorously and, after clearing, wash each portion again in a second separatory funnel with 5 cc. of water, then add the washings to the main aqueous soda solution of sodium salicylate. Dilute to a known volume, transfer an aliquot, representing about 100 mg. of salicylic acid, to a 200 cc. Erlenmeyer flask, make up to 100 cc, heat nearly to boiling, then run in from a burette 25-40 cc. of strong (about N/5) iodin solu- tion, sufficient to insure an excess during digestion and digest for an hour on a steam bath. Remove the free iodin with a few drops of sodium thiosulphate solution, decant the clear liquid through a tared Gooch, retaining most of the precipitate, tetraiodophenylenquinon (C6H2l20)2, in the flask. To the latter add 50 cc. of boiling water, digest 10 minutes on the steam bath, then filter, wash gradually all the precipitate into a Gooch, using for this purpose and the final washing about 200 cc. of hot water. Dry to constant weight in an air bath at 100°C. Mul- tiply the weight of the precipitate by 0.4654 to obtain the quantity of sodium salicylate present in the aliquot taken. Should the mixture contain caffein or antipyrin, or both, these substances will appear with the acetanilid in the first chloroform extract and may be determined as directed in the closely set type following 10. Should the acetanilid be replaced by acetphenetidin in the mixture, the general procedure would not be materially altered, the acetphenetidin being weighed directly after recovery from its washed chloro- form solution as separated from the sodium salicylate. If, instead of sodium sal- icylate, the mixture contains the free acid or its ammonium salt, add a larger quan- tity of sodium bicarbonate prior to extraction with chloroform to insure the fixation of salicylic acid. In the analysis of a mixture of caffein, acetanilid, sodium salicylate and codein sulphate, the following procedure is recommended: (1) Extraction of caffein, acet- anilid and salicylic acid from the acidified solution; (2) Washing the chloroform solution with aqueous soda solution for the recovery of salicylic acid, preliminary to its treatment with iodin solution; (3) Separation of caffein and acetanilid as directed under 3 and 4; (4) Recovery of codein from the solution of its sulphate after treatment with sodium bicarbonate and chloroform. XXIX] DRUGS 359 Caffein, Acetanilid and Quinin Sulphate in Mixtures. 21 preparation of sample and solution.-tentative. Transfer to a scparatory funnel one or more average unit doses of the powdered sample, add 20 cc. of water and 50 cc. of chloroform, then 10 drops of dilute sulphuric acid and extract in the usual way. After clearing, wash the solvent in a second separatory funnel with 5 cc. of water prior to transferring to a 200 cc. Erlenmeyer flask. Repeat the foregoing operations with two 50 cc. portions of chloroform, finally distilling the combined chloroform solution to about 10 cc. by gentle heat. 22 CAFFEIN AND ACETANILID.— TENTATIVE. Treat the chloroform residue obtained in 21 as directed under 3 and 4. 23 QUININ SULPHATE.— TENTATIVE. Combine the wash water, used in the second separatory funnel in 21, with the solution of quinin bisulphate, add a slight excess of solid sodium bicarbonate, ex- tract with three 50 cc. portions of chloroform, wash each portion with 5 cc. of water in a second separatory funnel and then pass through a dry filter into a 200 cc. Erlen- mej^er flask. Distil by gentle heat to about 5 cc, evaporate on a steam bath to apparent dryness, dissolve the amorphous alkaloid in 5 cc. of neutral alcohol and titrate with N/50 hydrochloric acid to a faint red, using 2 drops of methyl red as an indicator. Heat on a steam bath until most of the alcohol has been expelled, adding, if necessary, sufficient acid to maintain the acid reaction. From the total number of cc. of acid employed in the titration calculate the quinin sulphate. One cc. of N/50 hydrochloric acid is equivalent to 8.73 mg. of quinin sulphate. If the mixture contains acetphenetidin in place of acetanilid, proceed as out- lined above, except that the separation of caffein and acetphenetidin is conducted as directed under 6 and 7. Caffein, Acetanilid and Codein Sulphate in Mixtures. 24 prspar\tio.v o? s\m?l3 axd sdlunox.-tsxrative. Proceed as directed under 21 . 25 caffein and acetanilid. -tentative. Proceed as directed under 22. 26 CODEIN sulphate.— tentative. Proceed as directed under 23 to the point indicated by the sentence "Distil by gentle heat to about 5 cc". Transfer the chloroform solution of codein with suffi- cient solvent to a small, tared beaker, evaporate to apparent dryness on a steam bath, add a few drops of alcohol to the amorphous residue, then a like amount of water and evaporate again. Finally cool and allow the usually crystalline product to stand until the weight becomes constant. The weight of this residue multiplied by 1.3144 gives the quantity of codein sulphate present. This result should be checked volumctrically. Dissolve the residue in 3-5 cc. of neutral alcohol and titrate with N/50 sulphuric acid to a faint red, using methyl red as an indicator. From the number of cc. of standard acid employed calculate the amoimt of codein sulphate. Ojic cc. of N/50 sulphuric acid is equivalent to 7.87 rag. of codein sulphate. The quantity of codein sulphate as found by weight will usually be slightly greater than that determined by titration. 360 METHODS OF ANALYSIS [Chap, Caffein, Acetanilid, Quinin Sulphate and Morphin Sulphate in Mixtures. 27 preparation of sample and solution.— tentative. Transfer to a separatory funnel an amount (containing not less than one fourth grain of morphin) of the powdered sample equal to, or a multiple of, a unit dose, add 20 cc. of water and 10 drops of dilute sulphuric acid, then extract with three 50 cc. portions of alcohol-free chloroform, wash each portion in a second separatory funnel with 5 cc. of water and add the combined washings to the alkaloidal solu- tion in the first separatory funnel. Filter the chloroform extracts through a small, dry filter into a 200 cc. Erlenmeyer flask and distil by gentle heat to about 10 cc. 28 CAFFEIN AND ACETANILID.— TENTATIVE. Treat the chloroform residue as directed under 3 and 4. 29 QUININ SULPHATE.— TENTATIVE. Add to the solution of quinin and morphin sulphates, obtained in 27, 4-5 cc. of sodium hydroxid solution (1 to 10) and extract with four 40 cc. portions of chloro- form, wash each portion with 5 cc. of water and pass the clear solvent through a small, dry filter into a 200 cc. Erlenmeyer flask. Remove the solvent by gentle distillation and titrate the residual quinin with N/50 hydrochloric acid as directed under 23. 30 MORPHIN SULPHATE.-TENTATIVE. Wash the filter, employed in 29, with 5 cc. of water and add to the aqueous alkaline solution of the alkaloid. Now add 0.5 gram of ammonium chlorid (or an amount slightly in excess of that required to free the morphin as well as convert all sodium hydroxid to sodium chlorid) and, to the resulting ammoniacal solution, add 45 cc. of chloroform and 5 cc. of alcohol, then extract in the usual way, washing the solvent in a second separatory funnel with 5 cc. of water. After clearing, pass the chloroform through a small, dry filter into a 200 cc. Erlenmeyer flask. Repeat the extraction with three 40 cc. portions of chloroform, washing and filtering as be- fore, finally collecting all the solvent in an Erlenmeyer flask and distilling to about 10 cc. Transfer with chloroform to a small, tared beaker, evaporate to apparent dryness, add 0.5 cc. each of water and neutral alcohol, start crystallization by stirring with a glass rod and finally evaporate to dryness. Cool and allow to stand until the weight becomes constant. Check the weight of morphin, thus determined, by titration with N/50 sulphuric acid, using a drop of methyl red as an indicator. Dissolve the alkaloid in 1-2 cc. of warm, neutral alcohol, then add the standard acid to a faint red. Evaporate most of the alcohol on a steam bath, adding, if necessary, sufficient acid to main- tain the acid reaction. From the volume of acid used calculate the morphin sul- phate. One cc. of N/50 sulphuric acid is equivalent to 7.58 mg. of morphin sulphate. Tragacanth. 31 VOLATILE ACIDITY^.— tentative. The quantity of volatile (acetic) acidity developed in the acid hydrolysis of gum tragacanth {Astragalus gummijer) affords a valuable index of the purity of this com- modity when compared with results obtained by similar treatment of so-called "Indian gum" {Cochlospernum gossypium and Sterculia urens). The term "vola- tile acidity" expresses the nmnber of cc. of N/10 potassium or sodium hydroxid required to neutralize the volatile (acetic) acid obtained by distilling with steam the products of the action of boiling aqueous phosphoric acid on 1 gram of the gum. XXIXJ DRUGS 361 Treat 1 gram of the whole or powdered sample in a 700 cc. round-bottomed, long- necked flask for several hours in the cold with 100 cc. of water and 5 cc. of sirupy phosphoric acid until the gum is completely swollen. Boil gentlj' for 2 hours under a reflux condenser. A very small amount of cellulose substance will remain undis- solved. Now distil the hydrolyzed product with steam, using a spray trap' to con- nect the distillation flask with the condenser and continue until the distillate amounts to 600 cc. and the acid residue to about 20 cc. Do not concentrate too far, as this would scorch the non-volatile, organic decomposition products and possibly contaminate the distillate. Titrate the distillate with N/10 potassium hydroxid, using 10 drops of phenolphthalein as an indicator, finally boiling the liquid under examination until a faint pink color remains. Correct the result by a blank de- termination and express the final result in terms of the number of cc. of N/10 alkali required, as in the above definition. While tragacanth yields a practically colorless solution when boiled with aqueous phosphoric acid, Indian gum, on the other hand, gives a pink or rose solution. This reaction may be used as a preliminary test for the detection of Indian gum. Levant Wormseed. 32 santonin.— tentative. Extract 10 grams of the sample, ground to pass a 30 mesh sieve, in a Soxhlet ex- traction apparatus for 3 hours with chloroform. Distil oflf the chloroform until 7-8 cc. remain; add 100 cc. of 5% barium hydro.xid solution and heat on a steam bath until the odor of chloroform has disappeared. Boil 5 minutes, cool and pass carbon dioxid (washed through sodium bicarbonate solution to remove traces of acid) until saturated. Filter on a small Biichner funnel, using suction, and wash twice with 10 cc. of water. Heat the filtrate on a steam bath, add 5 cc. of 25% hydrochloric acid and warm 5 minutes. Cool until lukewarm and extract with 20, 15 and 15 cc. of chloroform, passing the solvent through a small filter into a flask. Evaporate to dryness, removing the last traces of chloroform. Dissolve in 7.5 grams (9.5 cc.) of absolute alcohol, warming gently if necessary. Then add 42.5 cc. of water heated to 60°-70°C., stopper the flask and allow to cool. Start crystal- lization at this point by scratching the side of the flask with a rod or by seeding with a minute crystal of santonin. (Solutions containing a liberal amount of santonin, kept in a cool place for 24 hours, have been found in a supersaturated condition where this precaution was not observed.) Maintain the flask and contents at a temperature of 15°-17°C. for 24 hours. Filter and wash at 15''-17°C. with two 10 cc. portions of 15% alcohol by weight. Dry the flask and filter at 100°C., dis- solve the santonin left in the flask and on the filter in chloroform and filter into a tared beaker. Wash the flask and paper thoroughly with chloroform, evaporate the combined filtrate and washings, dry at 100°C. to remove all traces of chloroform and weigh. To the weight found add 0.04 gram for the santonin dissolved in the dilute alcohol and multiplj' the total by 10 to obtain the per cent of santonin. Nitroglycerin in Tablets. 33 preparation of sample.-tentative. (a) Crush 25 tablets under 10 cc. of anhydrous ether in a 25 cc. cylinder by means of a stout glass rod. Rinse the rod with a little anhydrous ether, allow the insoluble material ^o settle and decant the solution into a 50 cc. jjraduated flask. Wash the residue repeatedly with 5 cc. portions of anhydrous ether, decant the washings into the flask until it is filled to the mark, stopper and mix well. Designate this solution as .1. 362 METHODS OF ANALYSIS [Chap. Add 10 cc. of water to the residue, mix Vv^ell and transfer the mixture to a small separatory funnel by means of a little water. Extract with 3 successive portions of 10, 5 and 5 cc. of ether. Collect the ether extracts in a 50 cc. beaker and designate this solution as B. (b) Dis'ntegrate 25 tablets in a small beaker with 10 cc. of water, breaking up any lumps with a glass rod, and transfer by means of a little water to a sepa- ratory funnel. Rinse the beaker with 10 cc. of ether and transfer this also to the funnel. Shake thoroughly, draw off the aqueous layer and transfer the ether through a funnel, containing a little cotton, to a 50 cc. graduated fiask. Repeat the extraction with successive portions of ether until the flask is filled to the mark, stopper and mix well. Designate this solution as C. In hand-made and soft compressed tablets, the method described under fa) is preferred, since the direct extraction of the dry crushed material with ether re- moves most of the nitroglycerin. In hard compressed tablets, the direct extraction is often not nearly so complete and, in such cases, the method described under (b) is to be preferred. Nitrate Method^. — Tentative. 34 REAGENTS. (a) Phenoldisulphonic acid solution. — Prepare as directed under IV, 14 (a). (b) Standard nitrate solution.—Dissolve 0.7217 gram of potassium nitrate in 1 liter of water. Evaporate 10 cc. of this solution just to dryness in a porcelain dish on a steam bath. Cool and treat the residue with 2 cc. of the phenoldisulphonic acid solution, rubbing with a glass rod to insure intimate contact. After 5-10 min- utes dilute to 250 cc. Each cc. of this solution contains 0.004 mg. of nitrogen. Add an excess of potassiiun hydroxid solution to an aliquot of this solution and dilute to 100 cc. (Do not use sodium or ammonium hydroxid.) It is advisable to pre- l)are a standard of approximately the same color as the unknown. 35 DETERMINATION. Place 20 cc. of the ether solution, A or C under 33, in a dried, tared 50 cc. beaker. Evaporate the solvent in a vacuum desiccator containing sulphuric acid. Apply the vacuum gradually, to prevent boiling. Allow the beaker to remain in the vacuum 30 minutes after the ether has evaporated. Weigh and calculate the ether extract per tablet. Treat the residue with 2 cc. of the phenoldisulphonic acid solu- tion, rotating the beaker so that the reagent comes in contact with the entire inner surface. After 10 minutes add water and wash into a 100 cc. flask. Dilute to the mark and place 10 cc, representing 1 tablet, in a 100 cc. flask, add about 50 cc. of water and a few drops more of 20% potassium hydroxid solution than is required to neutralize the acid. Dilute to the mark and compare the color with that pro- duced when a standard nitrate solution is similarly treated. Any convenient col- orimeter or Nessler tubes may be used. Multiply the nitrate nitrogen found by 5.4 to obtain the equivalent of nitroglycerin. When 33 (a) is used for the p.eparat'on of the sample, a correction, deter- mined as directed in 37, should be made for the amount of nitroglycerin in B under 33, using all of B instead of an aliquot. Nitrite or Modified Hay Method^ .—Tentative. 36 REAGENTS. (a) Sulphanilic acid solution. — Prepare as directed under IV, 12 (b). (b) Alpha-naphlhylamin hydrochlorid solution. — Prepare as directed under IV, 12 (c). XXIX] DRUGS 363 (C) Standard nitrite solution. —S^c\g\\ out 0.220 gram of dry silver nitrite [XV, 18 (c)], dissolve in a small quantity of hot water and decompose with a slight ex- cess of sodium chlorid solution. When the solution becomes clear, dilute to 1 liter with nitrite-free water. Dilute 5 cc. of this solution to 1 liter with nitrite-free water. The second dilution, containing 0.0001 mg. of nitrous nitrogen per cc, is the stand- ard to be used. [Cf. IV, 12 (d)] 37 DETERMINATION. Place 5 cc. of the ether solution, A or C under 33, in a 50 cc. beaker dilute with 5-10 cc. of alcohol and add about 5 cc. of 0.5% alcoholic potassium hy- droxid. Cover with a watch glass and allow to stand 10 minutes. Place on a steam bath, boil, remove the watch glass and, when most of the liquid has evaporated, add about 25 cc. of water and return to the steam bath until about half the liquid has evaporated or until the odor of alcohol can no longer be detected. Cool and dilute with nitrite-free Avater to 250 cc. Each cc. of this solution represents 0.01 of a tablet. Introduce an aliquot, representing 0.02-0.04 mg. of nitroglycerin, into a 100 cc. graduated flask, dilute with sufficient nitrite-free water to make the volume 90-95 cc, add a drop of concentrated hydrochloric acid, then 2 cc. of the sulphanilic acid solution and 2 cc. of the alpha-naphthylamin hydrochlorid solution. Com- plete the volume with nitrite-free water. Prepare at the same time and in the same manner standards containing known amounts of sodium nitrite. Stopper the flasks, mix well and compare the colors after 30 minutes, using any convenient colorimeter or Nessler tubes. Multiply the nitrite nitrogen found by the factor 8, which has been determined experimentally, to obtain the equivalent of nitroglycerin. When 33 (a) i.s used for the preparation of the sample, a correction, deter- mined as directed above, should be made for the amount of nitroglycerin in B under 33, using all of B instead of an aliquot. Pepsin in Liquids.-tentative. 38 REAGENTS. (a) Standard pepsin. — Powder a good grade of U. S. P. pepsin and pass it through a No. 60 sieve; dry in vacuo over calcium chlorid, again pass through a sieve and preserve in a stoppered bottle. Ascertain the exact pepsin equivalent of the dry powder by the U. S. P. method'" and express in percentage based on the assaraptiou that the U. S. P. product is 100% pure. (b) Standard pepsin solutions. — Weigh off definite amounts of the standard pep- sin into the requisite quantity of N/10 hydrochloric acid to make solutions con- taining 5 and 0.5 mg. of pepsin per cc. These should be freshly prepared. (C) Ricin solulion. — Grind commercial ricin, similar to the "Ricin Prepiirat nach Jacoby", to a No. 60 powder, mix thoroughly, dry and keep in a desiccator. Digest 1 gram of this powder for an hour at 37.5°C. in 100 cc. of 5% sodium chlorid solution, cool, filter and use at once for the assay. PREPARATION OF SOLUTIONS. 39 (a) Dilute solulion of the sample. — Dilute the sample with a measured amount of N/10 hydrochloric acid until, upon digestion at 37.5°C., 1 cc. requires approximately 15 minutes to digest the precipitate obtained by mixing 2 cc. of the ricin solution and 0.5 cc. of N/10 h3'drochloric acid. To 50 cc. of this diluted preparation add the requisite quantity of water or of N/5 hj'drochloric acid to make the preparation of N/10 acid strength when diluted with N/10 acid to 90 cc. Preserve the sample in 364 METHODS OF ANALYSIS [Chap. a refrigerator. (Solid pepsin preparations may often be extracted with hydro- chloric acid of appropriate strength and prepared for assay in the same manner.) (b) Dilute comparison solution of the sample. — Add 1 cc. of N/10 hydrochloric acid to 9 cc. of the dilute solution of the sample. (C) Dilute inactive solution of the sample. — Immerse a stoppered glass vessel, con- taining 45 cc. of the dilute solution of the sample and 5 cc. of N/10 hydrochloric acid, in boiling water for 15 minutes and filter. (d) Standard solution containing 0.5 mg. of active U. S. P. pepsin per cc. — Im- merse a stoppered test tube containing 18 cc. of the dilute solution of the sample in boiling water for 10 minutes and, after cooling, add 2 cc. of the standard pepsin solution, containing 5 mg. of pepsin per cc, and filter if necessary. If the solutions to be tested are not clear, filter through hardened filters. If, however, they cannot thus be clarified, make check comparison tubes containing the same amounts of the preparation made up in the same way with 2 cc. of water in place of the ricin solution used in the determination. 40 DETERMINATION. To each of 15 tubes, add from a burette 2 cc. of the ricin solution and 0.5 cc. of N/10 hydrochloric acid, heat to 37.5°C. and add the following quantities of the solutions: To the first 5 tubes, add 0.00-1.00 cc. of the dilute comparison solution of the sample in 0.25 cc. increments, and 1.00-0.00 cc. of the dilute inactive solution of the sample in 0.25 cc. decrements. To the next 5 tubes, add 1.00-0.00 cc. of the dilute inactive solution of the sample in 0.25 cc. decrements and 0.00-1.00 cc. of the standard solution containing 0.5 mg. of active U. S. P. pepsin per cc. in 0.25 cc. increments. To the last 5 tubes, add 1.00-0.00 cc. of N/10 hydrochloric acid in 0.25 cc. decrements and 0.00-1.00 cc. of the standard pepsin solution containing 0.5 mg. of pepsin per cc. in 0.25 cc. increments. By comparing any tube of the first group of 5 with the tubes in the remaining groups the degree of proteolytic activity of the dilute comparison solution of the sample may be matched against known amounts of standard pepsin both in ordi- nary acid medimn, last group of 5, and in the same medium as the sample itself, second group. Introduce the acid and the dilute inactive solution of the sample into the tubes first and then pour in the solutions to be tested as rapidly as possible from gradu- ated pipettes, noting the total time consumed in the process after adding the pepsin. After the addition of the solution to be tested, again immerse the test tubes in the 37.5°C. bath, preferably arranged in corresponding order in a partitioned square or oblong wire rack, such as is used in bacteriological work. Shake and examine the tubes from time to time for 1-2 hours, noting the time when the digestion begins and ends. In case of very weak solutions they may be allowed to digest over- night. If the rate of digestion is the same in each group, the dilute comparison solution of the sample contains exactly 0.5 mg. of pepsin per cc. If the rate is more rapid in the first group than in the others, it is stronger, the comparative strength being closely indicated by the time of action in the tube containing less of the solution. If the rate of clearing is more rapid in the last group than in the second, some in- terfering substance is present and must be removed by dialysis, or by evaporation in vacuo at a low temperature until, upon re-examination and further dilution or concentration, the rate of digestion is identical or nearly so in each series. Smaller quantities of pepsin may be determined in the same way by comparing XXIX] DRUGS 365 them with more dilute solutions of standard pepsin. Thus 0.05 mg. of U. S. P. pepsin can be readily detected by the nearly complete solvent action on the ricin precipitate in less than 2 hours. A marked action on the ricin within the same time is shown by 0.005 mg. For all practical purposes the absence of an appreciable sol- vent action after 4 hours digestion indicates the absence of pepsin. Express the re- sult in per cent, assuming U. S. P. pepsin to be 100% pure and calculating the result according to the dilution found necessary in preparing the dilute solution of the sample. Turpentine. 41 color.-tentative. Fill a 200 cc. flat-bottomed colorimeter tube, graduated in mm., to a depth of 40-50 mm. with the turpentine. Place the tube in a colorimeter and place on or under it a No. 2 yellow Lovibond glass. Over or under a second graduated tube in the colorimeter, place a No. 1 yellow Lovibond glass and run in the same turpen- tine until the color matches as nearly as possible the color in the first tube. Read the difference in depth of the turpentine in the 2 tubes. If this difference is 50 mm. or more, the turpentine is "standard". 42 SPECIFIC GRAVITY.-TENTATIVE. 20° C Determine the specific gravity at -p— ^ by means of a pycnometer. The specific gravity may also be determined somewhat less accurately at any convenient tem- perature with a plummet, correcting the result by using the factor 0.00082 for each degree that the temperature of the determination differs from the standard tem- perature. 43 REFRACTIVE INDEX.-TENTATIVE. Determine the refractive index at any convenient temperature with an accurate instrument and calculate the result to 20°C., using the correction factor 0.00045 for each degree that the temperature of the determination differs from 20°C. 44 DISTILLATION.-TENTATIVE. Use an ordinary Engler flask (the internal diameter of the side tube must be 6-7 mm.) and condenser'* and heat the flask in a glycerin or oil bath'^. Fit the flask with a thermometer reading 145°-200°C. Place 100 cc. of the turpentine in the flask, connect with the condenser and distil. Conduct the distillation so that the distillate passes over at the rate of 2 drops per second. Note the initial distilling temperature and the percentage distilling below 170°C. POLYMERIZATION. -TENTATF/E. 45 REAGENT. S8N sulphuric acid. — Mix 140 grams of concentrated sulphuric acid with suflBcient liquid, fuming sulphuric acid (about 10 grams) to obtain an acid slightly stronger than 38N. Determine the exact strength'* of this mixture and also of the concen- trated acid as follows: Weigh out 6-8 grams in a bulb, having a capillary tube in the lower end and a tube with a stop-cock in the upper end, fitted with a platinimi wire for suspending on a balance. (The bulb is filled by the aid of a slight vacuum, and the lower end of the capillary is emptied by closing the stop-cock simultaneously with the withdrawal of the capillary from the acid; after which it is wiped off first with a wet and then with a dry piece of cloth.) Run the acid into cold water, make up to volume and titrate an aliquot of the solution against standard alkali or add an 366 METHODS OF ANALYSIS excess of ammonium hydroxid to an aliquot, evaporate to dryness, dry to constant weight at 120°-130°C. and weigh as ammonium sulphate. Calculate the sulphur trioxid content of the acid and add sufficient concentrated sulphuric acid to make it exactly 82.38% of SO3. The acid must be carefully protected against absorption of water from the air. 46 DETERMINATION. Place 20 cc. of the 38N sulphuric acid (100.92%) in a graduated, narrow-necked Babcock flask, stopper, place in ice water and cool. Add slowly 5 cc. of the turpen- tine. Mix the contents gradually, cool from time to time and do not allow the tem- perature to rise above 60°C. When the mixture no longer warms up on shaking, agi- tate thoroughly, place in a water bath and heat to 60°-65°C. for about 10 minutes, keeping the contents of the flask thoroughly mixed by vigorous shaking 5-6 times. Cool to room temperature and fill the flask with concentrated sulphuric acid until the unpolymerized oil rises into the graduated neck. Centrifugalize 4—5 minutes at about 1200 revolutions per minute, or allow to stand for 12 hours. Read the un- polymerized residue, notice its consistency and color and determine its refractive index. BIBLIOGRAPHY. » U. S. Bur. Chem. Bull. 152, p. 239. 2 .1. Ind. Eng. Chem., 1915, 7: 519. 3 Ibid.. 1914, 6:665. * U. 8. Bur. Chem. Bull. 162, p. 197. *> J. Ind. Eng. Chem.1915, 7: 681. "Ibid., 1912, 4:374. ■< U. S. Bur. Chem. Circ. 94, p. 4. 8 Am. J. Pharm., 1911, 83: 359. 3 Trans. Roy. Soc. Edinburgh, 1885, 32: 67. i« U. S. P., VIII, 1905, p. 334. " Stillman. Engineering Chemistry. 4th ed., 1910, p. 503. « U. S. Bur. Chem. Bull. 135, p. 2(3. 13 U. S. Bur. Chem. Circ. 85, p. 12. INDEX Abrastol 151 Acetanilid 352, 356, 358, 359, 360 and acetphenetidin, in mixtures 354 sodium salicylate, in mixtures 357 Acetphenetidin (phenacetin) 353, 354, 356 and salol, in mixtures 356 Acetyl value, of fats and oils 310 Acidity, in cheese 296 cream of tartar 343 distilled liquors 243 prepared mustard , 322 total, in coffees 333 fruits and fruit products 178 tanning liquors 55 volatile, in coffees 333 water-soluble, of feeds 119 Acids, fixed, in tomato products 324 vinegars 256 wines 240 insoluble, in fats and oils (Hehner number) 307 mineral, free, in fruits and fruit products 179 vinegars 258 soluble, in fats and oils 306 total, in beers 250 canned vegetables 186 tomato products ; 324 vinegars 256 wines 238 volatile, in beers 250 canned vegetables 186 fruits and fruit products 178 tomato products 324 vinegars 256 wines 239 insoluble, in fats and oils (Polenske number) 308 soluble, in fats and oils (Reicherl-Meissl number) 307 Agar agar 180 Albrech Method for lemon and orange peel color 264 Albumin, in milk 288 wheat flour 188 Alcohol, in beers 249 confectionei^y 132 distilled liquors 243 flavoring extracts 259, 262, 266, 267, 268 367 368 INDEX Alcohol, in fruits and fruit products 177 vinegars 253 wines 193 extract, in spices 318 precipitate, in fruits and fruit products 179 vinegars 257 Aldehydes, in distilled liquors 244 total, in flavoring extracts 262, 265 Alkali, black, in irrigating water 51 Alkalies, total, in soils 27 Alkalinity, in industrial water 50 Allihn's Method for dextrose 106 Almond extract 266 Alum, in baking powders 345 Aluminium, in soils 22 waters 43 oxid, in plants 30 Amaranth 158 Ammonia, in baking powders 346 meat and meat products 274, 281 free and albuminoid, in waters 36, 41 Amthor Test Modified by Lasche for caramel 248 Anise extracts 269 Annatto 168 Antipyrin 354 Arsenic, in baking powders 350 foods 171 mineral water 48 oxid, total, in insecticides and fungicides 66 water-soluble, in insecticides and fungicides 67, 68, 72 total, in insecticides and fungicides 63, 68, 69, 71, 72 Arsenious oxid, sodium acetate-soluble, in insecticides and fungicides 65 total, in insecticides and fungicides 64, 66, 69, 71 water-soluble, in insecticides and fungicides 65, 67, 72 Ash, in baking powders 345 beers 250 cacao products 327 canned vegetables 185 coffees 331 dairy products 287, 292, 293, 294, 296 distilled liquors 243 flavoring extracts 260, 264 foods and feeding stuffs 79 fruits and fruit products i 178 leathers 59 meat and meat products 271, 280 plants 29 saccharine products 128, 133, 137 spices and other condiments 317, 321, 323 tea 335 vinegars 256 INDEX 369 .\sh, in wheat flour 187 wines 238 Babcock Method for fat in dairy products 289, 292, 298 Bacteria, in tomato pulp, etc 325 Baking powders 339-350 Batnihl Test for gluten in wheat flour 189 Baudoin Test for sesame oil 314 Beef fat, in lard 314 Beers 249-251 Benedikt-Lewkoivitsch Method for acetyl value in fats and oils 310 Modified, for moisture in soap 73 Benzaldehyde, in almond extract 266 Benzoic acid 143-145 Beta-Naphthol 151 Blarez Method, Modified, for fluorids 149 Borates 146 Bordeaux mixture 69 with lead arsenate 72 Paris Green 71 Boric acid 146 in mineral water 49 Bromin, in mineral water 47 Butter 294 renovated 295 Butyric acid, in tomato products 324 Cacao products 327-330 Caffein, in coffees - 332 drugs 352, 353, 354, 359,. 360 tea 336 and acetanilid, in mixtures 351 acetphenetidin (phenacetin), in mixtures 353 antipyrin, in mixtures 353 acetanilid and codein sulphate, in mixtures 359 quinin sulphate, in mixtures 359 and morphin sulphate, in mixtures. . . 360 Calcium, in mineral water 43, 50, 51 plants 31 soils 23 arsenate 69 carbonate required, in soils 28 Canned vegetables 185-186 Capsicum, in ginger extract 268 Caramel, in distilled liquors 248 Carbon, inorganic, in soils 19 in plants 29 organic, in soils 18 dioxid, in insecticides and fungicides 70, 71, 72 mineral water 42 plant ash 29 available, in baking powders 343 370 INDEX Carbon, dioxid, residual, in baking powders 343 total, in baking powders 339 Carbonic and bicarbonic acids, in waters 42, 49 Casein, in dairy products 287, 294 milk chocolate 329 Cassia extract 267 Cereal foods 187-191 Chace Method for pinene 265 total aldehydes in flavoring extracts 262, 265 Cheese 296 Chicory, in coffee 334 Chlorin, in butter 294 cyanids 73 meat extracts 280 plants 32, 33 waters 38, 41, 49, 51 wheat flour 189 wines 238 Chlorophyll 168 Cholesterol and phytosterol, in mixtures of animal and vegetable fats 311 Cinnamon extract 267 Citral, in flavoring extracts 263, 265 Citric acid, in fruits and fruit products 182 Clarifying reagents for optical methods 82 Clove extract 267 Coating and glazing substances, in coffees 333 Cochineal 168 Codein sulphate 359 Coffee, green 331 roasted 331 Coffees 331-334 Color, in beers 249 potable water 35 vinegars 257 residual, in vanilla extract 261 value, in vanilla extract 261 wheat flour 191 water-insoluble, in whiskies 248 Coloring matters 155-169 in dairy products 292, 293, 295 wines 240 natural 163, 168 separation by immiscible solvents 157 Colors, insoluble in amyl alcohol, in distilled liquors 248 vanilla extract 261 Condensed milk (sweetened) 293 (unsweetened) 293 Condiments 317-326 Cook Method for glycerol in meat extracts 285 Copper, in foods 175 INDEX 371 Copper; in insecticides and fungicides 70,71,72 carbonate 69 oxid, total, in insecticides and fungicides 65 reducing substances in spices and other condiments 318, 322 Cottonseed oil 313 Coumarin, in vanilla extract 259 Cowles Method for malic acid value 13S Cream 292 of tartar in wines 240 Creatin, in meat and meat products 275, 284 Creatinin, in meat extracts 285 Crude fiber, in cacao products 327 cofifees 333 foods and feeding stuffs 118 spices and other condiments 318, 322 tea 336 wheat flour 187 Cyanids, sodium and potassium 72 Dairy products 287-298 Dextrin, in beers 250 fruits and fruit products 179 honey I34 vinegars 258 wines 241 Dextrose, in foods and feeding stuffs 106 honey I34 Diastase, in honey 136 Distilled liquors 243-248 Drugs 351-366 Dulcin 152 Dyes, acid I59 basic 159 coal tar I55 oil-soluble 156 Emery Method for beef fat in lard 314 Erythrosine 158 Esters, in distilled liquors 244 Ether extract, in butter 294 confectionery 131 foods and feeding stuffs 80 meat 271 prepared mustard 322 wheat flour 187 volatile and non-volatile, in spices 318 Extract, in beers 249 distilled liquors 243 wines 236 cold water-soluble, in wheat flour 188 372 INDEX Facing, in tea 337 Fat, in cacao products 328 coffees 334 dairy products 289, 292, 293, 295, 297 leathers 59 meat extracts 280 Fats and oils 299-315 Fatty acids, free, in fats and oils 310 liquid and solid, in fats and oils 309 Feder Anilin Chlorid Test for commercial invert sugar 136 Ferric oxid, in plants 30 Fertilizers 1-15 Fiehe Test (Bryan Modification) for commercial invert sugar 135 Fincke Method for formic acid in vinegars ^ 257 Fish oil, in the presence of vegetable oils 315 Flavoring extracts 259-269 Flour, wheat 187 Fluoborates 149 Fluorids 149 Fluosilicates 149 Folin Aeration Method for ammonia in meat 274 Food preservatives 141-154 Foods and feeding stuffs 79-119 Formaldehyde 147-149 solutions 75 Formic acid 152 in vinegars 257 Fruit products 177-184 Fruits 177-184 Fungicides 63-77 Furfural, in distilled liquors 244 Fusel oil, in distilled liquors 245 Galactan, in foods and feeding stuffs 118 Gelatin, as coating substance, in coffees 334 dairy products 291, 293 fruits and fruit products 180 meat and meat products 274, 281 Ginger, in ginger extract 268 cold-water extract 318 extract 267 Glazing substances, in coffees 333 Globulin, in wheat flour 188 Glucose, in leathers 60 commercial, in fruits and fruit products 179 saccharine products 130, 135 wines 237 Gluten, in wheat flour 189 Glutenin, in wheat flour 188 Glycerol, in beers 250 flavoring extracts 259, 262 INDEX 373 Glycerol, in meat extracts 285 vinegars 253 wines 236 Glycogen, in meat 276 Goldenberg-Geromonl-Heidenhain Method for total tartaric acid in baking powders 343 Gorier Method for caflfein in cofifee 332 Gum, in wines 241 Gunning Method for organic and ammoniacal nitrogen in fertilizers 7 Modified, for total nitrogen in fertilizers 8 Halphen Test for cottonseed oil 313 Hanus Method for iodin absorption number of fats and oils 305 Hardness, permanent, in industrial water 51 temporary, in industrial water 50 total, in industrial water 51 Hay Method, Modified, for nitroglycerin in tablets 362 Hedges Method, Modified, for total arsenious oxid in insecticides and fungicides 64 Hehner Method for formaldehyde 147 free mineral acids in vinegars 258 number, of fats and oils 307 Herzfeld Gravimetric Method for invert sugar 98 Modification of the alcohol extraction method for sucrose in beets. . . . 138 Sachs le Docte Method for sucrose in beets 139 Hess and Prescott Method, Modified, for vanillin and coumarin 259 Hide substance, in leathers 61 Hiltner Method for citral in flavoring extracts 263, 265 Honey 133-136 Hortvet Method for volatile acids in wines 239 and West Method for oil in anise and nutmeg extracts 269 cassia, cinnamon and clove extracts 267 Modified, for methyl salicylate in wintergreen extract 269 Howard Method, Modified, for oil in peppermint, spearmint and wintergreen ex- tracts 268 HUbl Method for iodin absorption number of fats and oils 304 Hydrocyanic acid, in almond extract 266 Hydrogen sulphid, in mineral water 41 Indigo carmine 158 Insecticides 63-77 Insoluble residue, in soils 22 Invert sugar, in foods and feeding stuffs 85 commercial, in honey 135 Iodin, in mineral water 47 absorption number of fats and oils 304 Iron, in mineral water 43 soils 22 and aluminium in mineral water 42, 50 Jorisscn Method for sucrol or dulcin 152 Test for salicylic acid 142 374 INDEX Kissling Method for nicotin in tobacco and tobacco extract 73 Kjeldahl Method for organic and ammoniacal nitrogen in fertilizers 5 Modified, for total nitrogen in fertilizers 8 -Gunning-Arnold Method for organic and ammoniacal nitrogen in ferti- lizers 7 Kleber Method for citral in lemon and orange oils 265 Koettstorfer number of fats and oils 306 Lactose, in cacao products 329 dairy products 288, 292, 293 foods and feeding stuffs 104 La Wall Method, Modified by Doyle, for capsicum in ginger extract 268 Leach and Lythgoe Method for methyl alcohol in distilled liquors 247 Method for coloring matters in milk 292 formaldehyde 148 Lead, in baking powders 346 arsenate 67-69 number, in maple products 137 vanilla extract 260 oxid, total, in insecticides and fungicides 67, 72 precipitate, in vinegars 255 Leathers 59-61 Leffman and Beam Method for soluble volatile acids in fats and oils 308 Lemon extracts 261 oil 264 in lemon extract 262 and orange peel color 264 Levant Wormseed 361 Levulose, in honey 134 Light Green S F yellowish 159 Lime-sulphur solutions 76-77 Lindo-Gladding Method for potash in fertilizers 12 Lithium, in mineral water 45 London purple 66-67 Low, A. H., Volumetric Method, Modified, for determining the amount of reduced copper 96 Lowenthal Method, Proctor Modification, for tannin in tea 336 Magnesium, in mineral water 44, 50, 51 plants 31 soils 23 Malic acid, in fruits and fruit products 181 value, in maple products 138 Maltose, in foods and feeding stuffs , 102 Manganese, in mineral water 47 plants 31 soils 23 Maple products 136- 138 Marcusson and Schilling Method for cholesterol and phytosterol 312 Marr Method, Modified, for inorganic carbon in soils 19 Marsh Method, Modified, for color insoluble in amyl alcohol 248 INDEX 375 Mayrhofer Method, Price Modification, for starch in meat 276 McGill Method, Modified, for starch in baking powders 345 Meat 271 bases in meat 274 extracts 280 and meat products 271-286 Melting point determinations 301 Metals, in foods 171-176 Methyl alcohol, in distilled liquors 246 flavoring extracts 261, 264 salicylate, in wintergreen extract 269 Micro-analysis of tomato pulp, ketchup, puree and sauce (paste) 324 Milk 287-292 fat, in milk chocolate 328 Mitchell Method for lemon and orange oils 262 Mohler test, Modified, for benzoic acid 144 Moisture, in cacao products 327 canned vegetables 185 coffees 331 dairy products 294, 296 fertilizers 1 foods and feeding stuffs 79 insecticides and fungicides 63, 66, 67, 69, 71, 72 leathers 59 meat and meat products 271 , 280 saccharine products 121, 133, 136 soils 17 spices 317 tea 335 wheat flour 187 Molds, in tomato pulp, etc 324 Morphin sulphate 360 Morpurgo Method for sucrol or dulcin 152 Munson and Walker Method for reducing sugars 86 Mustard, prepared 321 Muter Method, Modified by Lane, for liquid and solid fatty acids 309 Naphthol Yellow S 158 Nitrates, in fertilizers 5 meat and meat products 278, 285 wines 241 Nitrobenzol, in almond extract 267 Nitrogen, in fertilizers 5-12 leathers 61 nitrate salts, in fertilizers 11 non-volatile ether extract, in spices 317 saccharine products 129 albuminoid, in foods and feeding stuffs 80 alcohol-soluble, in meat extracts 284 amino, in foods and feeding stuffs 80 meat extracts 282 376 INDEX Nitrogen, amino, in wheat flour 188 ammoniacal, in fertilizers 10 connective tissue, in meat 273 nitrate, in waters 37, 41, 49 nitric and ammoniacal, in fertilizers 10 nitrite, in waters 37, 41 wheat flour 190 organic and ammoniacal, in fertilizers 5 in fertilizers 11 soluble and insoluble, in meat 273 total, in cacao products 327 dairy products 287, 292, 296 fertilizers 8-10 meat and meat products 273, 280 soils 21 spices 317 Nitroglycerin, in tablets 361 Non tannins, in tanning materials 54, 55 Nutmeg extracts 269 Odor, in potable water 35 Oil, in anise and nutmeg extracts 269 cassia, cinnamon and clove extracts 267 peppermint, spearmint and wintergreen extracts 268 Oleomargarine 295 Olive oil, in paprika 319 Orange extract 261 oil 264 in orange extract 262 1 158 Oxygen, dissolved, in potable water 40 required, in potable water 39 Parafiin, in confectionery 132 tea 337 Paris Green 63-66 Peanut oil 313 Pellet Aqueous Method for sucrose in beets 139 Pentosans, in foods and feeding stuffs 110 vinegars 257 wines 241 Peppermint extract 268 Pepsin, in liquids 363 Peptones, in meat and meat products 274 Petroleum ether extract, in coffees 333 tea 335 Phosphoric acid, in baking powders 346 beers 250 fertilizers 1-5, 14 mineral water 46 plants 31 INDEX 377 Phosphoric acid, in soils 22, 24 wines 238 soluble and insoluble, in vinegars 256 Phosphorus, soluble in N/5 nitric acid, in soils 27 total, in meat and meat products 271, 280 soils 25 water-soluble, in meat 271 Phytosterol, in mixtures of animal and vegetable fats 311 Pigments 155 used in tea for coloring or facing 337 Pinene, in lemon and orange oils 265 Plant constituents 29-33 Polarization, in foods and feeding stuffs 83, 84 fruits and fruit products 179 saccharine products 129, 133, 136 vinegars 255 wines 237 direct, in beers 250 Polenske Method for insoluble volatile acids in fats and oils 308 number, of fats and oils 308 Ponceau 3R 158 Potash in fertilizers 12-14 Potassium, in mineral water 45 plants 32 soils 24 total 26 bitartrate in baking powders 344 Preservatives, in foods 141-154 milk 291 wines 242 Protein, in beers 251 condensed milk 293 fruits and fruit products 179 prepared mustard 322 tea 336 wheat flour 187 alcohol-soluble, in wheat flour 187 coagulable, in meat and meat products 274, 281 crude, in foods and feeding stuffs 80 wines 241 insoluble, in meat extracts 281 Proteoses, in meat and meat products 274, 281 Quinin sulphate 359, 360 Raffinose, in beet products 84 Raw sugars, general directions for optical methods 81 Read Method for pigments used in tea for coloring or facing 337 Reducing substances, total, before inversion, in vinegars 255 sugars, in beers 250 foods and feeding stuffs 85, 109 378 INDEX Reducing sugars, in fruits and fruit products 179 saccharine products 131, 134, 137 wines 237 after inversion, in tomato products » 324 vinegars 255 before inversion, in tomato products 323 vinegars 255 other than dextrose, in foods and feeding stuffs 109 Refractive index, of fats and oils 300 lemon and orange oils 264 Reichert-Meissl Method for soluble volatile acids in fats and oils 307 number, of fats and oils 307 Renard Test, Modified, for peanut oil 313 Resin oil 313 Riche and Bardy Method for methyl alcohol in distilled liquors 246 Rimini Method for formaldehyde 148 Roese-Gottlieb Method for ether extract in confectionery 131 fat in dairy products 289, 293 Saccharin 145 Saccharine products 121-139 Sachsse Method, Modified, for starch 110 Salicylic acid 141-143 Salol, in drugs 357 Salt, in canned vegetables 185 dairy products 294, 296 prepared mustard 321 Sand, in plants 29 tomato products 323 Sangle-Ferriere Method for abrastol 152 Saponification number of fats and oils {Koettstorfer number) 306 Schlosing-Wagner Method for nitrates in meat 278 Schmidt-Bondzynski Method, Modified, for fat in cheese 297 Schuhe-Trommsdorf Method for required oxygen in water 39 Seeker Method for ginger in ginger extract 268 Serum, acetic, in milk 291 copper, in milk 291 sour, in milk 291 Sesame oil 314 Silica, in mineral water 42, 49 plants 29 Sinibaldi Method for abrastol 151 Slag, Thomas or basic 14-15 Smith, J. Lawrence, Method for total alkalies in soils 27 Method, Modified, for total arsenious oxid in insecticides and fungicides. 65 Soap 73 Soda lye 73 Sodium, in mineral water 45 plants 32 soils 24 chlorid, in tomato products 323 INDEX 379 Sodium salicylate 368 Soils 17-28 Solids, in dairy products 287, 292, 293 flavoring extracts 260, 264, 267 fruits and fruit products 177 leathers 61 saccharine products 122 spices and other condiments 321, 323 tanning materials 53, 55 vinegars 255 waters 35, 41, 49, 51 insoluble, in tomato products 323 non-sugar, in wines 237 soluble, in coffees 331 Soxhlet Method for dextrose 106 invert sugar in foods and feeding stuffs 86 Wein Method for lactose 104 Spdth Method for fats and waxes in coffee 334 Spearmint extract 268 Special tests for coal tar dyes permitted under the Federal Food and Drugs Act. 162 Specific gravity, in beers 249 distilled liquors 243 fats and oils 299 flavoring extracts 259, 261, 264 saccharine products 122 vinegars 253 wines 193 Spices 317 microscopic examination of 319 and added pungent materials in vinegars 258 other condiments 317-326 Spores, in tomato pulp, etc 325 Stahlschmidt Method, Modified, for caffein in coffee 332 Starch, in baking powders 344 cacao products 328 coffees 333 foods and feeding stuffs 110 fruits and fruit products 180 meat 276 saccharine products 131 spices 318 Strontium, in mineral water 44 Sucrol 152 Sucrose, in cacao products 329 condensed milk 293 flavoring extracts 260, 264 foods and feeding stuffs 81-85 fruits and fruit products 179 saccharine products 129, 134, 137, 138 tomato products. .' 324 wines 237 380 INDEX Sugar, as a coating and glazing substance, in coffees 333 house products 138 Sugars, in canned vegetables 186 cattle foods 109 distilled liquors 246 meat and meat products 278, 285 wheat flour 187 Sulphite-cellulose, in tanning materials 54 Sulphuric acid, in baking powders 346 mineral water 44, 50, 51 plants 32 soils 24 wines 238 Sulphur, in mustard 319 plants 32 Sulphurous acid 150 Sweetening substitutes, in fruits and fruit products 184 Tannin, in cloves and allspice 319 leathers 61 tanning materials 54 tea 336 wines 240 Tanning extracts 53 liquors 55 materials 53-57 raw and spent 56 Tartaric acid, free, in baking powders 344 wines 240 or combined in baking powders 343 total, in baking powders 343 fruits and fruit products 180 vinegars 257 wines 240 and tartrates in vinegars 257 Tartrazine 158 Tea 335-337 Thomas or basic slag 14-15 Tin, in foods 173 Titer test for fats and oils 302 Tobacco and tobacco extract 73-75 Tomato products 322 Tragacanth 360 Trillat Method for methyl alcohol in distilled liquors 246 Trowbridge and Francis Method for glycogen in meat 277 Turbidity, in potable water 35 Turmeric 168 Turpentine 365 Ulsch-Street Method for nitric and ammoniacal nitrogen in fertilizers 10 INDEX 381 Unsaponifiable residue, in fats and oils 312 Vanilla extract and its substitutes 259 resins 260 Vanillin, in vanilla extract 259 Van Shjke Method for amino nitrogen in meat extracts 282 Villavecchia Test for sesame oil 314 Vinegars 253-258 Volatile matter, in soils 17 oil, in tea 336 Volhard Method for chlorin in plant ash 32 Water extract, acidity of, in wheat flour 187 in tea 335 industrial 49-51 irrigating , 51-52 mineral 41-49 potable 35-41 Waters 35-52 Water-soluble material, in leathers 59 Waxes, in coffees 334 Wein Method for maltose 103 Wiley Method for melting point of fats and fatty acids 301 Wines 193-242 Winkler Method, as Modified by Drown and Hazen, for dissolved oxygen in water 40 Rideal and Stewart, for dissolved oxygen in water 40 Wintergreen extract 26S Winlon Method for soluble solids in coffees 331 Ogden and Mitchell Method for nitrogen in non-volatile ether extract. . 317 Wolff Method for free or combined tartaric acid in baking powders 343 Yeasts and spores, in tomato pulp, etc 325 Zinc, in foods 175 arsenite 69 THE END THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. 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