ELEMENTARYAPPLIED 
 CHEMISTRY 
 
 UC-NRLF 
 
 LEWIS B.ALLYN 
 
GIFT OF 
 
 AbmU 
 
ELEMENTARY 
 APPLIED CHEMISTRY 
 
 BY 
 
 LEWIS B. ALLYN 
 
 DEPARTMENT OF CHEMISTRY, STATE NORMAL SCHOOL 
 WESTFIELD, MASSACHUSETTS 
 
 For the world was built in order 
 And the atoms march in tune." 
 EMERSON 
 
 GINN AND COMPANY 
 
 BOSTON NEW YORK - CHICAGO LONDON 
 
GIFT 
 
 COPYRIGHT, 1912, BY 
 LEWIS B. ALLYN 
 
 ALL RIGHTS RESERVED 
 912.11 
 
 nrpf. 
 
 GINN AND COMPANY PRO- 
 PRIETORS BOSTON U.S.A. 
 
PREFATORY NOTE 
 
 The object of the exercises in this book is to create and 
 to foster a real love for and interest in the great science of 
 chemistry, to give the pupil a broader outlook on life, 
 and to cause him to feel that he is a factor in the busy, 
 living world. 
 
 These experiments and tests have been of personal value 
 to hundreds of earnest students ; possibly they may be of 
 value to you. If you know of some one who would profit 
 by the information you may receive, pass it on. 
 
 445101 
 
CONTENTS 
 
 SECTION PAGE 
 
 I. FILTRATION 1 
 
 II. ACIDS AND ALKALIS 5 
 
 III. ALKALIS IN TEXTILE ANALYSIS 7 
 
 IV. ACIDS AND ALKALIS IN THE QUALITATIVE ANALYSIS OF 
 
 SOILS 9 
 
 V. DETECTION OF SOME OF THE COMPOUNDS PRESENT IN 
 
 PLANTS 13 
 
 VI. EXERCISES WITH STANDARD SOLUTIONS 16 
 
 VII. SANITARY ANALYSIS OF WATER 28 
 
 VIII. EXAMINATION OF BAKING POWDER 35 
 
 IX. ANALYSIS OF MILK 41 
 
 X. EXAMINATION OF ICE CREAM, CHEESE, AND CONDENSED 
 
 MILK 52 
 
 XI. DISTILLATION EXPERIMENTS 54 
 
 XII. DETECTION OF COAL-TAR DYE 76 
 
 XIII. IDENTIFICATION OF VEGETABLE COLORS 79 
 
 XIV. RAFFIA DYEING 81 
 
 XV. CHEMISTRY OF STAINS 88 
 
 XVI. EOOD PRESERVATIVES 90 
 
 XVII. EXAMINATION OF TOOTH POWDERS 95 
 
 XVIII. EXPERIMENTS WITH GLUCOSE 97 
 
 XIX. EXAMINATION OF HEADACHE POWDERS 102 
 
 XX. TESTS FOR ARSENIC 105 
 
 XXI. METHOD FOR TESTING PAINT AND OILS 109 
 
 XXII. DETERMINATION OF FOOD VALUES 113 
 
 XXIII. TESTING URINE 118 
 
 XXIV. SELECTED EXERCISES 120 
 
 INDEX 125 
 
 vii 
 
SUGGESTIONS TO TEACHER AND PUPIL 
 
 Be sure that the work done is correct, and then certify it. 
 
 The use of blanks similar to the one on page x gives a 
 suggestion of importance to the task performed and is con- 
 ducive to honest, accurate work, and, best of all, to a regard 
 for the truth. 
 
 Much time will be saved by making counterpoises with 
 stoppered vials and fine shot for beakers, crucibles, evap- 
 orating dishes and specific-gravity flasks. Test the accuracy 
 of these tares occasionally. 
 
 If you are not sure of a reaction, work with a sample 
 which is known to contain the substance in question. For 
 example, if the odor of phenylcarbamine is unknown, heat 
 a few drops of commercial anilin with 5 cc. of stock solution 
 of KOH. Add a cubic centimeter of chloroform, agitate 
 gently, cool, and note the odor. 
 
 Form the habit of using a pipette instead of a graduate 
 whenever special accuracy is desired. 
 
 Distilled water should be used for dilutions and solu- 
 tions, especially for solutions of precision. 
 
 Many semifluid substances may be ashed by allowing 
 the flame to strike the surface of the material, meanwhile 
 applying a gentle heat to the bottom of the crucible. 
 
 Save products -and samples. Bottle and label them. A 
 collection is an inspiration and an incentive. 
 
 Notebooks should be illustrated by mounted samples, 
 cuts, and clippings from newspapers and magazines. 
 
 ix 
 
ELEMENTARY APPLIED CHEMISTRY 
 REPORT OF CHEMICAL ANALYSIS 
 
 Sample- 
 
 Obtained from. 
 
 Manufactured by_ 
 
 
 
 Test 
 
 
 Coal-tar dye 
 
 
 Vegetable colors 
 
 
 C ethyl 
 
 
 Alcohol^ 
 ^methyl 
 
 
 Mineral matter or metals .... 
 
 
 Organic compounds (miscellaneous) . 
 
 
 Bases 
 
 
 Radicals 
 
 
 Essential oils 
 
 
 
 
 Glucose 
 
 
 Acetanilid or phenacetin 
 
 
 Equation 
 
 
 f fraudulent .... 
 
 
 Adulteration ^ 
 t injurious .... 
 
 
 Oualitv . 
 
 
 
 
 REMARKS 
 
 I hereby certify that the above is correct to the best of my knowledge. 
 
 Name 
 
 Date 19 
 
SUGGESTIONS TO TEACHER AND PUPIL xi 
 
 Much collateral reading should be encouraged. The 
 following books and pamphlets are valuable: 
 
 LEACH, A. E. Food Inspection and Analysis. John Wiley & Sons. 
 
 WILEY, H. W. Foods and their Adulteration. Blakiston. 
 
 BLYTH, A. W. Foods, their Composition and Analysis. D. Van 
 Nostrand Company. 
 
 PEARSON. Jensen's Milk Hygiene. J. B. Lippincott. 
 
 OLSEN, J. C. Pure Foods. Ginn and Company. 
 
 OLSEN, J. C. Quantitative Chemical Analysis. D. Van Nostrand 
 Company. 
 
 SNYDER. Human Foods. The Macmillan Company. 
 
 ALLEN, A. H. Commercial Organic Analysis. D. Van Nostrand 
 Company. 
 
 COHN. Tests and Reagents. John Wiley & Sons. 
 
 Bulletin No. 107, Bureau of Chemistry, United States Department 
 of Agriculture. 
 
ELEMENTARY APPLIED 
 CHEMISTRY 
 
 SECTION I 
 
 FILTRATION 
 
 Application to Qualitative and Quantitative Analysis (2-Part 
 Compound). A very satisfactory remedy for tonsillitis is a 
 mixture consisting of equal parts of sulfur and powdered 
 sugar. This is a recognized specific, and at one time was 
 sold as a patent medicine at fifty cents per ounce. The 
 instructor should prepare a quantity of the specific, varying 
 the proportions slightly. Pass the mixture several times 
 through a fine sieve. 
 
 (a) Qualitative Work. Place a spoonful of the powder in 
 a beaker. Add 50 cc. of water, boil, and filter. Test both 
 filtrate and residue in any way you choose. Of what is the 
 powder composed ? How do you know ? 
 
 Copy and sign the following statement : 
 
 I hereby certify that a mixture called Tonsillitis Specific and 
 examined by me contains 
 
 Name. 
 Date 
 
 (b~) Quantitative Work. Weigh as exactly as possible 
 3 to 5 g. of the specific upon a carefully balanced filter 
 paper. Adjust to a funnel and wash with repeated portions 
 of hot water until the filtrate ceases to darken when a few 
 
 l 
 
' APPLIED CHEMISTRY 
 
 drops are heated with strong H 2 SO 4 ; or until a drop leaves 
 no dark-colored residue when evaporated upon a piece of 
 platinum foil. 
 
 Dry the residue over a water bath ; remove and cool. 
 
 Place the duplicate filter paper in the opposite scale pan 
 and weigh the sulfur directly. Determine the weight of 
 the sugar by difference. 
 
 Copy and sign the following, or use a printed blank : 
 
 The sample of Tonsillitis Specific as analyzed by me contains 
 
 per cent sulfur, per cent sugar. 
 
 I hereby certify that the above is correct to the best of my 
 
 knowledge. 
 
 Name 
 
 Application to the Analysis of a 3-Part Compound. (<r) In- 
 troduce a definite amount of gunpowder (2 to 3 g.) into a 
 balanced filter paper. Wash with repeated portions of hot 
 water. Test the filtrate for residue with the platinum foil as 
 before, using only a drop or so for the test. Collect the filtrate 
 and evaporate it to dryness in a tared evaporating dish. 
 
 (6) Dry the residue remaining in the filter paper. Ex- 
 tinguish all flame in the vicinity, and wash the residue with 
 three or four 10-cc. portions of CS 2 . Collect filtrate No. 2 
 in a small beaker. Blow on it gently through a pointed 
 tube until evaporation is complete, or allow it to evaporate 
 spontaneously. What remains ? 
 
 Dry the black residue over a water bath and weigh with 
 the counterpoised filter. 
 
 Record and certify your results. 
 
 Character and per cent of the white salt . . . 
 
 Character and per cent of the black residue . . 
 
 Character and per cent of the yellow substance . 
 
 Read on the history and composition of gunpowder. 
 
FILTRATION 3 
 
 Application to Quantitative Analysis of Soil. Thoroughly 
 dry about 5 g. of soil procured by the pupil. Weigh 
 exactly upon a balanced and folded filter paper. Place in 
 a funnel and wash with successive portions of hot water 
 until the filtrate does not darken when heated with an 
 equal volume of concentrated H 2 SO 4 . Dry the filter paper 
 and contents at 100 C. Reweigli and calculate the loss of 
 weight as soluble matter. Transfer the dried residue to a 
 counterpoised porcelain or quartz crucible and determine 
 its exact weight. Gently heat to full redness with occa- 
 sional stirring, being careful not to lose any of the material. 
 Continue heating until all of the organic matter is burned 
 away. Cool the crucible in a desiccator and weigh the resi- 
 due. Calculate the loss as insoluble organic matter. 
 
 Tabulate as follows : 
 
 Soluble matter % 
 
 Insoluble organic mutter % 
 
 Mineral matter % 
 
 Total 100% 
 
 I low have you seen nitration employed outside of .school? 
 
 What is another name for the process? 
 
 What kind of substances may be separated by nitration? 
 
 Make a list of mixtures containing such substances. 
 
 Application to Commercial Analysis of Tea. The approxi- 
 mate value of tea may be determined by calculating the per 
 cent of matter which is not soluble in hot water. The in- 
 soluble matter should not be in excess of 60 per cent. If 
 over this amount, the presence of spent or exhausted leaves 
 is indicated. 
 
 Place exactly 2 g. of the finely powdered tea in a balanced 
 and folded filter paper. Extract with successive portions of 
 boiling water until the filtrate runs clear. Dry the residue 
 
4 ELEMENTARY APPLIED CHEMISTRY 
 
 at 100 C. Cool and re weigh. Calculate by difference in 
 weight the per cent of water-soluble matter. 
 
 Test samples of tea of various prices, and answer the 
 question, Does the price indicate the quality of tea based 
 upon matter insoluble in boiling water ? 
 
 What per cent of insoluble matter has the tea which is 
 used at your home ? 
 
 To isolate Theine, the Alkaloid of Tea. Extract a spoon- 
 ful of high-grade tea in 50 cc. of boiling water. Filter the 
 liquid and add 10 cc. of chloroform. Transfer the mixture 
 to a separatory funnel, shake the contents vigorously for a 
 minute, and allow the chloroform to settle. Draw it off 
 into a clean, dry watch glass and allow it to evaporate at 
 room temperature. Note the white, silky crystals and the 
 pleasant odor of the theine. 
 
 Repeat the above experiment, substituting coffee for 
 tea. The alkaloid of coffee is called what ? It is identical 
 with that of tea. Its chemical symbol is C 8 H 10 N 4 O 2 + H 2 O. 
 What per cent of nitrogen does it contain ? 
 
 Application to a Domestic Analysis of Oysters. The de- 
 termination of the amount of water added to shucked oys- 
 ters is important from the viewpoint of the consumer. The 
 per cent of water that may be separated by means of a 
 strainer or sieve should not exceed 15 per cent. 1 Weigh 
 on a trip balance about a pint of the sample as purchased. 
 Place in a flat-bottomed sieve and allow to drain into a 
 weighed dish for twenty minutes, stirring gently from time 
 to time. Determine the weight and per cent of the exterior 
 liquor. Determine the weight and per cent of the drained 
 oysters by difference. 
 
 1 Merck's Report, July, 1910, p. 189. 
 
SECTION II 
 ACIDS AND ALKALIS 
 
 Detection in Everyday Compounds. The instructor will 
 show samples of acids in solid, liquid, and gaseous form, to 
 do away with the impression that all acids are liquids. 
 
 Show samples of the common alkalis. 
 
 Discover the effect of acids and alkalis upon the vari- 
 ous indicators phenolphthalein, methyl orange, cochineal, 
 carmine, and litmus. 
 
 Take home some litmus paper cut into small strips. Test 
 different articles foods at the table, substances in the 
 kitchen, laundry, etc. Be sure that the substance tested, if 
 a solid, is either dissolved in water or well moistened. 
 
 One pupil tested the following : cream of tartar, ashes, 
 salt, milk, apple juice, borax, sugar, baking soda, washing 
 soda, soap, vinegar, tea, kerosene, tooth powder, coffee, 
 butter, stomach bitters. 
 
 Arrange your results in three columns, thus : 
 
 Acid Alkaline Neutral 
 
 Give the chemical names and symbols of as many of the 
 above list as possible. What per cent of the foods eaten 
 during the day were acid ? alkaline ? neutral ? 
 
 Determine the reaction of the soil from your lawn or 
 garden. What advantage is it to know this reaction ? 
 
 Thoroughly moisten 20 to 50 g. of the soil and in- 
 sert two pieces of litmus paper, one red, the other blue. 
 
 6 
 
6 ELEMENTARY APPLIED CHEMISTRY 
 
 Allow them to remain undisturbed for an hour or even 
 overnight. 
 
 What would you suggest as a suitable dressing for an 
 acid or " sour " soil ? for an alkaline one ? 
 
 What plants have a distinctly acid reaction ? Do you 
 know of any fruits which are not acid ? Find out the name 
 of the acid which imparts the sour taste to the common 
 sheep sorrel (Tlumex acetosella), apples, oranges, grapes, 
 rhubarb, etc. What acid is found in the membranous cov- 
 ering of nuts ? Mention some of the alkalis which are 
 found in nature. 
 
SECTION III 
 ALKALIS IN TEXTILE ANALYSIS 
 
 Determination of the Per Cent of Wool and Cotton in 
 Fabrics. Wool is soluble in a solution of NaOH or KOH. 
 Cotton is insoluble in this reagent. 
 
 Qualitative Work. Place a small piece of the sample in 
 a test tube or crucible. Cover with 20 per cent KOH 
 
 FIG. 1. Mixed goods heated with KOH, showing cotton residue 
 
 and boil for two or three minutes. If the sample en- 
 tirely dissolves, what is the per cent of wool ? Suppose it 
 partially dissolves, what is indicated ? Experiment with 
 bits of cotton, wool, and mixed goods until you are 
 familiar with the action of the caustic solution upon these 
 substances. 
 
 Caution. Take great care that none of the hot alkali 
 comes in contact with the flesh or clothing. If this does 
 happen, apply dilute HC1 at once. 
 
 7 
 
8 ELEMENTARY APPLIED CHEMISTRY 
 
 Quantitative Work. If a portion of the cloth dissolves, cut 
 a second sample about 8 cm. square. Determine the exact 
 weight. Place in a beaker or large evaporating dish and 
 cover with the caustic potash. Boil for three minutes, or 
 until the wool is dissolved. Remove the cotton residue, tak- 
 ing care not to lose any detached threads. Rinse thoroughly. 
 Add a drop of phenolphthalein and sufficient HC1 to make 
 slightly acid. Wash, dry at 100 C., and re weigh. Calcu- 
 late the per cent of wool and cotton. Devise a method for 
 testing silk. 
 
SECTION IV 
 
 ACIDS AND ALKALIS IN THE QUALITATIVE 
 ANALYSIS OF SOILS 
 
 The appended list comprises the more important plant 
 foods, and the majority of them can be easily detected in 
 common soil. 
 
 Water Sulfuric acid as sulfates 
 
 Lime (CaCO 3 ) Hydrochloric acid as chlorids 
 
 Carbon dioxid Nitric acid as nitrates 
 
 Ferric oxid (Fe 2 O 3 ) Magnesia (MgO) 
 
 Soda (Na 2 O) Sand (SiO 2 ) 
 Potash (K 2 O) 
 
 Calcium Carbonate. Place 10 g. of the soil in a test 
 tube and add 2 cc. of HC1. An effervescence indicates the 
 presence of a carbonate. This effervescence may frequently 
 be heard when the action is only faintly visible, by placing 
 the ear near the mouth of the test tube. 
 
 Add enough water to make a thin paste and boil for about 
 two minutes. Make alkaline with ammonia, and filter. Test 
 the clear filtrate with an equal volume of (NH 4 ) 2 C 2 O 4 . A 
 cloudiness or flocculent precipitate, which forms on standing, 
 indicates the presence of calcium. 
 
 CaCO 3 + 2 HC1 = ? 
 CaCl a + (NH 4 ) a C a 4 =? 
 
 Ferric Oxid. First Test. Boil 4 g. of the soil with 10 cc. 
 of HC1 (5 parts of acid and an equal volume of water). 
 Filter and test half of the filtrate with ammonia added in 
 
 9 
 
10 ELEMENTARY APPLIED CHEMISTPvY 
 
 excess. A reddish-brown, flocculent precipitate assures the 
 presence of iron in the sample of soil. 
 
 Second Test. To the other half of the nitrate add a few 
 drops of potassium sulfo-cyanide (KCNS). A blood-red 
 color is seen if ferric oxid is present in the original soil. 
 Test further by adding a little HgCl 2 to a cubic centimeter 
 of the red liquid. The color should be destroyed. Write the 
 reactions which take place in the first and second tests. 
 
 Soda and Potash. Boil 50 g. of the soil in an equal 
 volume, of water, stirring constantly. Allow the undis- 
 solved matter to settle and decant the clear liquid. Evapo- 
 rate this, preferably over a water bath, to about 5 cc. Clean 
 a platinum wire by heating until it gives no color to the 
 blue Bunsen flame. Dip the wire into the concentrated 
 filtrate and place immediately in the outer flame. A yellow 
 coloration indicates soda. A lilac or violet color, best seen 
 through a piece of cobalt-blue glass, indicates potash. 
 
 Sulfuric Acid as Sulfates. To a little BaCl 2 solution add 
 a few drops of the filtrate left from the soda and potash 
 experiment. Boil. A precipitate insoluble in acids indi- 
 cates the presence of sulfates. Write the reaction between 
 sodium sulfate and barium chlorid. 
 
 Hydrochloric Acid as Chlorids. To two or three cubic 
 centimeters of the soda filtrate add a few drops of AgNO g . 
 Churn the contents of the test tube. A white, curdy precipi- 
 tate soluble in ammonia indicates the presence of chlorids 
 in the soil. 
 
 Since other substances are likely to precipitate the silver 
 solution, decant or filter off the ammoniacal solution and add 
 an excess of HC1. If a second precipitate is seen or a decided 
 milkiness is evident, the presence of chlorids is assured. 
 NaCl + AgNO 8 = ? 
 
ACIDS AND ALKALIS 
 
 11 
 
 Nitric Acid as Nitrates. To one volume of the soda- 
 potash filtrate add two volumes of strong H 2 SO 4 free from 
 nitrates. Allow the mixture to cool. Incline the test tube 
 and cautiously add a few drops of a concentrated solution 
 of FeSO 4 , so that the liquids will not mix. A brownish 
 ring at the junction of the two 
 solutions assures the presence 
 of nitrates. 
 
 Phosphoric Acid as Phos- 
 phates. To 5 cc. of the soda- 
 potash filtrate add a few drops 
 of ammonium molybdate in 
 HNO 3 . Warm the evaporating 
 dish gently. The presence of 
 phosphates is indicated by a 
 lemon-yellow color, or, if there 
 is a considerable quantity pres- 
 ent, by a yellow precipitate. 
 
 Magnesia (MgO). Boil 25 g. 
 of the soil in 50 cc. of water and 
 10 cc. of HC1. Filter and evap- 
 orate the filtrate to about 5 cc. 
 Add a few drops of NH 4 C1 and 
 
 an equal volume of NH 4 OH. FlG<2 . Soil before and afterboil- 
 If a precipitate forms, filter and 
 test the filtrate with HNa PC) . 
 
 ing in strong HC1. The residue 
 is sand 
 
 A white crystalline precipitate of MgNH 4 PO 4 , soluble in 
 acids, assures the presence of magnesium in the soil. 
 
 Sand. Wash 10 g. of the soil in a 250-cc. beaker with 
 a small stream of water, stirring constantly until all the 
 humus is washed out. Boil the residue in strong HC1 
 for five minutes. Sand is the principal substance left. 
 
12 . ELEMENTARY APPLIED CHEMISTRY 
 
 Examine with a magnifying glass. What material do you 
 recognize ? Can you suggest what some of the original 
 rock might have been ? How could you make this experi- 
 ment quantitative ? 
 
 Another important constituent of soils is organic nitro- 
 gen. Its detection and determination should be omitted 
 until the pupil is familiar with the Gunning method for 
 nitrogen, q.v. 
 
SECTION V 
 
 DETECTION OF SOME OF THE COMPOUNDS 
 PRESENT IN PLANTS 
 
 By far the greater part of the growing plant is carbon 
 and water. How could you prove this ? 
 
 This list comprises other compounds present in plants 
 and vegetable matter. 
 
 Organic nitrogen Phosphates 
 
 Chlorophyl Sulfates 
 
 Starch Chlorids 
 
 Potash and soda Iron 
 
 Manganese (infrequently) Silica 
 
 Organic Nitrogen. Grind a small handful of grass or 
 hay through a meat chopper. Mix with an equal weight 
 of soda lime or with strong KOH, and heat gently in an 
 Erlenmeyer flask, in the mouth of which is suspended a 
 strip of moist red litmus paper. The ammonia given off 
 will turn the test paper blue and prove the presence of 
 organic nitrogen. 
 
 Chlorophyl. Chlorophyl is the green coloring matter 
 common to growing plants. 
 
 Grind a handful of grass or green leaves, or scrape the 
 green layer from any woody stem. Triturate in a mortar 
 with enough alcohol to cover the mass. Decant or filter 
 the green liquid. Allow the alcohol to evaporate spon- 
 taneously. The chlorophyl remains as an intensely green 
 substance. 
 
 13 
 
14 ELEMENTARY APPLIED CHEMISTRY 
 
 When extracted from suitable kinds of leaves, as spinach, 
 parsley, etc., the chlorophyl is sometimes used for color- 
 ing confections, jellies, and beverages. Of what use is 
 chlorophyl to plants? 
 
 Starch. Grind a few kernels of corn or any kind of 
 grain ; scrape a potato or bruise any kind of root. Boil 
 with 10 cc. of water. Cool the contents of the tube and 
 add a few drops of iodin. A distinct blue coloration is 
 proof of the presence of starch. 
 
 Potash and Soda. First Test. Place a handful of dried 
 grass in a white enameled pan or upon a porcelain tile. 
 Light it with a blazing splint. When it has stopped burn- 
 ing collect the residue in a porcelain crucible. Repeat the 
 experiment several times until the crucible is half full. 
 Heat until the contents are thoroughly ashed. Sometimes 
 the ash will be greenish, due to the presence of manganese, 
 but more frequently it will be white or light brown. Care 
 must be exercised lest the ash fuse to the crucible. 
 
 Wash the ash into a beaker and boil in 25 cc. of water. 
 Allow the undissolved material to settle, and reserve. Ex- 
 amine the clear liquid directly for potash and soda by the 
 flame test, as directed for the analysis of soils. If the results 
 are not positive, evaporate 10 cc. of the liquid to dry ness 
 and repeat the test. Is the liquid acid or alkaline ? 
 
 Second Test. Cut the bottom from a quart bottle or use 
 a glass percolator. Loosely plug the neck of the percolator 
 with absorbent cotton. Fill about two thirds full of sifted 
 wood ashes, through which allow half a liter of warm water 
 to pass. Collect the filtrate in a large evaporating dish or 
 enameled pan. Evaporate to dryness, but do not char. The 
 grayish- white substance is potash and soda, or the " lye " 
 used in the early settlements for making soft soap. Dissolve 
 
COMPOUNDS PRESENT IN PLANTS 15 
 
 in a little water and treat with phenolphthalein, cochineal, 
 or litmus. Apply the flame test. 
 
 Phosphates, Sulfates, and Chlorids. Separate the unused 
 portion of the liquid obtained in the first or second test 
 into three parts and apply the appropriate tests, as directed 
 under soil analysis. 
 
 : Iron. Boil the residue saved from the undissolved ash 
 with a few cubic centimeters of HC1. Decant the liquid 
 and test for iron with KCNS. 
 
 Silica. The residue from the iron test is mainly silica. 
 Wash with water, allow to settle, decant the liquid, and 
 rub the grayish material with the rounded end of a glass 
 rod. A distinct scratching sound can usually be heard. 
 
 Tabulate those exercises in which you have used an acid 
 or an alkali as a reagent. In which of these tests have you 
 found an acid or an alkali ? 
 
SECTION VI 
 EXERCISES WITH STANDARD SOLUTIONS 
 
 Titration and Standard Solutions. The strength of many 
 solutions may be determined with great accuracy by adding 
 definite volumes of other solutions of known strength, which 
 will react chemically with them. The process is known as 
 titration, and is of great importance in chemical analysis. 
 
 The added solution is called a standard solution. It is 
 made to contain an accurately determined weight of chemical 
 substance in a definite volume. 
 
 A standard solution which contains 1 g. of replaceable 
 hydrogen per liter is known as a normal solution. Standard 
 solutions may be spoken of in terms of normal solutions, as 
 1/2, 1/10, 1/50, etc., usually written N/2, N/10, N/50. 
 
 The amount of a given substance to be dissolved in dis- 
 tilled water and made up to a liter will vary directly as its 
 molecular weight and inversely as the number of replace- 
 able hydrogen atoms represented in its molecule. Thus a 
 liter of normal HC1 must contain 36.5 g. of acid, since its 
 molecular weight is 36.5 and only one atom of replaceable 
 hydrogen is present. A decinormal solution of this acid 
 will contain 3.65 g. per liter, while a cubic centimeter will 
 contain 0.00365 g. 
 
 A liter of normal H 2 SO 4 must contain 49 g. of acid, 
 since its molecular weight is 98, and 2 atoms of replace- 
 able hydrogen are present. N/10 H 2 SO 4 will contain 4.9 g. 
 per liter. 
 
 16 
 
EXEECISES WITH STANDABD SOLUTIONS 17 
 
 A liter of normal oxalic acid (H 2 C 2 O 4 + 2 H 2 O) must 
 contain 63g. of acid, since its molecular weight is 126 and 
 it contains 2 atoms of replaceable hydrogen. 
 
 To prepare a liter of N/10 oxalic acid, weigh exactly 
 6.3 g. of acid of the highest purity, which has not lost its 
 water of crystallization, and transfer to a liter measuring 
 flask. Add about 500 cc. distilled water and agitate to dis- 
 solve the acid. This done, make up to the mark on the 
 neck with more distilled water. Turn into a clean, dry 
 bottle and mix thoroughly. 
 
 A cubic centimeter of any normal acid will exactly neu- 
 tralize a cubic centimeter of any normal alkali. A liter of 
 normal NaOH must contain 40 g. of the hydrate, since its 
 molecular weight is 40. A liter of normal KOH must con- 
 tain 56 g. of the salt because its molecular weight is 56. 
 
 That one may know when enough of a standard solution 
 has been added to neutralize or to complete the reaction, it 
 is customary to employ a third or neutral substance called 
 an indicator. Litmus, phenolphthalein, cochineal, methyl 
 orange, potassium chromate, etc. are often used. 
 
 Phenolphthalein is a good general indicator, but must 
 not be employed when more than traces of CO 2 are present. 
 To prepare, dissolve 1 g. of the crystals in 100 cc. of 95 per 
 cent alcohol. To use, add two or three drops of the alco- 
 holic solution to the acid or to the alkaline solution under 
 examination. In acid or in neutral solutions phenolphthal- 
 ein is colorless, but the smallest excess of alkali turns it a 
 vivid purple-red. 
 
 To prepare a liter of N/10 NaOH, weigh roughly 4 g. 
 of the pure hydrate, transfer to a liter flask, and make up 
 to the liter mark with distilled water. When the hydrate has 
 dissolved, transfer to a large bottle and mix thoroughly. 
 
18 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 The solution must now be standardized by the N/10 oxalic 
 acid previously made. 
 
 By means of an accurate pipette transfer 10 cc. of the 
 NaOH solution to a beaker. Add two or three drops of 
 phenolphthalein. Set the beaker on a white 
 tile or sheet of white paper and draw into it 
 from a burette just enough N/10 oxalic acid 
 so that the last drop destroys the lingering 
 trace of pink in the alkali. Note carefully 
 the amount of acid required. 
 
 Suppose 12 cc. are used ; the alkali is too 
 strong, for 1 cc. of the acid must neutral- 
 ize 1 cc. of the alkali. Add 50 cc. of dis- 
 tilled water to the NaOH solution, mix well, 
 and again titrate 10 cc. By observing the 
 change made by the 50 cc. of water one 
 may easily calculate the amount of 
 water necessary to bring the alkaline 
 solution to the exact tenth-normal 
 strength. 
 
 Suppose only 8 cc. of the acid are 
 required to neutralize the solution ; 
 the NaOH is too weak. Add a drop 
 of saturated NaOH solution, mix well, 
 and titrate a second 10-cc. portion. 
 The requisite amount of alkali to be 
 added may be calculated. Thus by 
 adding water or alkali as required, an exact balance may 
 be secured. Work for perfect standardization. 1 
 
 1 For those wishing to go more into detail with volumetric solu- 
 tions, Olsen's "Quantitative Analysis" (D. Van Nostrand Co.) will be 
 helpful. 
 
 FIG. 3. A convenient 
 type of burette 
 
EXERCISES WITH STANDARD SOLUTIONS 19 
 A cubic centimeter of N/10 NaOH is equal to 
 
 Acetic acid (HC 2 H 3 O 2 ) 0.0060 g. 
 
 Boric acid (H 3 BO 3 ) 0.0062 g. 
 
 Citric acid (H 3 C 6 H 5 O 7 , H 2 O) 0070 g. 
 
 Lactic acid (HC 3 H 5 O 3 ) 0.0090 g. 
 
 Malic acid (C 4 H 6 O 5 ) 0.0067 g. 
 
 Oxalic acid (H 2 C 2 O 4 , 2 H 2 O) 0.0063 g. 
 
 Sulfuric acid (H 2 SO 4 ) 0.0049 g. 
 
 Tartaric acid (H 2 C 4 H 4 O 6 ) 0.0188 g. 
 
 Determine the Acidity of Oranges or Lemons calculated 
 as Citric Acid. Weigh or counterpoise a small, clean, dry 
 evaporating dish. In this place 2 to 3 g. of orange juice 
 free from pulp. If lemon juice is used, 1.5 to 2 g. is suffi- 
 cient. Add two or three drops of phenolphthalein (^phe- 
 nolphthalein, 1 g.; alcohol, 100 cc.). Fill a burette to the zero 
 mark with N/10 NaOH or take any other convenient mark 
 as zero. Allow this standard solution to drop slowly into 
 the fruit juice until the first permanent trace of pink appears 
 in the well-mixed solution. If, after standing for a minute, 
 the pink color disappears, add another drop of the alkali. 
 The fruit juice has been titrated with N/10 alkali. 
 
 CALCULATION 
 1 cc. of N/10 NaOH is equivalent to 0.007 g. of citric acid. 
 
 Suppose the weight of the orange juice and evaporating 
 
 dish is 15.82 g. 
 
 Suppose the weight of the evaporating dish is .... 13.30 
 
 Weight of the orange juice is 2.52 g. 
 
 Suppose at the end of the reaction the burette reads . . 13.80 cc. 
 
 Suppose the zero point was 10.50 
 
 Number of cubic centimeters of N/10 NaOH used . 3.3 cc. 
 
 3.3 x .007 = .0231 g. of citric acid in the 2.52 g. of juice. There- 
 fore citric acid is present to the extent of 0.916 per cent. 
 
20 ELEMENTAKY APPLIED CHEMISTRY 
 
 Test the acidity of commercial lime and lemon juices. 
 The U.S.P. requires about 7 per cent of citric acid. 
 
 Determine the Purity of Cream of Tartar. Place exactly 
 half a gram of the sample in a clean beaker and dissolve 
 in boiling water. Add the phenolphthalein solution as in the 
 preceding experiment and titrate with decinormal NaOH. 
 After the first pink color appears, heat nearly to boiling. 
 If the color disappears, add another drop of the alkali. 
 Half a gram of pure cream of tartar requires approximately 
 26.6 cc. (26.595) of N/10 NaOH to neutralize it. 
 
 If your balance is sufficiently accurate, weigh exactly 
 0.188 g. Dissolve in hot water and titrate, using phenol- 
 phthalein. If pure, it will require 10 cc. of the N/10 alkali. 
 
 Determine the Purity of Baking Soda. Every cubic cen- 
 timeter of N/10 baking soda must contain .0084 g. of 
 HNaCO 3 . Why? 
 
 Titrate exactly half a gram of the sample with N/10 HC1, 
 using methyl orange as an indicator. 
 
 How many cubic centimeters were required ? Suppose the 
 sample were absolutely pure, how many cubic centimeters 
 of the N/10 acid would be required to neutralize it ? 
 
 What is the per cent of purity ? Write the reaction 
 between HC1 and HNaCO 3 . 
 
 Determine the Per Cent of Lactic Acid in Milk. Fresh 
 milk should not contain over .2 per cent of acid. Cream 
 for the best butter should contain from .5 to .65 per cent. 
 
 Into a clean white evaporating dish or teacup place 9 cc. 
 of milk or cream, being sure to rinse the graduate into 
 the cup. Titrate with N/10 NaOH, using phenolphthalein 
 as an indicator. Stir the contents of the cup frequently 
 with a glass rod. The rod must not be taken from the 
 dish lest some of the contents be lost. Neither must alkali 
 
EXERCISES WITH STANDARD SOLUTIONS 21 
 
 from the burette spatter upon it. The first permanent tint 
 of pink in the milk indicates the end of the operation. The 
 color should remain pink after one minute. 
 
 The number of cubic centimeters of the standard alkali 
 used, indicates directly in tenths of one per cent the amount 
 of acid present. Thus : 
 
 6 cc. of the alkali = .6 per cent of acid. 
 9.3 cc. of alkali = .93 per cent of acid. 
 
 An Exercise in testing Vinegar. " Vinegar is formed by the 
 action of an organism found in the 'mother' of vinegar upon 
 weak alcoholic solutions. 
 This organism serves in 
 some way to carry the 
 oxygen of the air to the 
 alcohol. The sour taste is 
 'largely due to acetic acid " 
 (Remsen). 
 
 The following equations 
 illustrate the process of so- 
 called acetic fermentation : 
 C a H 6 0+0=C 2 H 4 0+H,0. 
 
 alcohol 
 
 CHO+0-HCHO. 
 
 acetic acid 
 
 The physical and chemi- 
 cal examination of vinegar 
 
 FIG. 4. 
 
 (Magnified) 
 
 Vinegar eels.' 
 (Wilson) 
 
 is full of interest. Examine a few drops under a low- 
 power microscope and see if you can find any of the so- 
 called " vinegar eels." They are best seen after allowing 
 a large test tube of vinegar to remain undisturbed for 
 several hours. The eels are usually near the surface of 
 the liquid. 
 
22 ELEMENTARY APPLIED CHEMISTEY 
 
 Total Acidity. Introduce exactly 6 cc. of the sample into 
 a clean beaker and set upon a white paper or tile in a good 
 light. Titrate with N/10 NaOH, using phenolphthalein as 
 an indicator. 
 
 The number of cubic centimeters of the decinormal alkali 
 used, divided by 10, represents the per cent of acetic acid. 
 
 CALCULATION 
 
 Suppose 34.3 cc. of the standard alkali are required to neutralize 
 
 34 3 
 6 cc. of the vinegar ; then = 3.43 per cent of acetic acid. 
 
 Proof. 1 cc. of N/10 NaOH neutralizes 0.006 g. of acetic acid. 
 
 34.3 x .006 = 0.2053 g. of acetic acid. 
 
 Therefore 6 g. (or 6 cc.)of vinegar contain 3.43 per cent of acetic acid. 
 
 The acidity of pure cider vinegar should not be less 
 than 4.5 per cent. 
 
 Total Solids. Weigh exactly 10 g. of the vinegar into a 
 tared crucible or evaporating dish and evaporate to dryness 
 for two hours. Cool in a desiccator, weigh, and calculate 
 the per cent of the residue. The total solids should not fall 
 below 2 per cent by weight if the sample is cider vinegar. 
 
 Ash. Place the vessel containing the total solids on a 
 suitable triangle and burn to ash at a low red heat. Cool 
 and weigh. 
 
 The ash should not be less than 0.25 per cent. Its reac- 
 tion to litmus should be distinctly alkaline. If it is not, 
 it contains some mineral acid which must be determined. 
 Gather some of the ash on the loop of a clean platinum 
 wire and apply the flame test. View through the cobalt- 
 blue glass if necessary. What base is present ? 
 
 Add a few drops of 10 per cent HC1. What radical 
 is evident? In the ash of pure cider vinegar potassium 
 carbonate is prominent. 
 
EXERCISES WITH STANDARD SOLUTIONS 23 
 
 Ashby's Test for Mineral Acids. Prepare a solution of log- 
 wood by dissolving 0.5 g. of the extract in 100 cc. of boiling 
 water. Place one drop of this solution on the bottom of an 
 evaporating dish and dry over a water bath. To the dried 
 residue add a drop of vinegar and dry again. Pure vinegar 
 gives a yellow stain. Free mineral acids color the residue red. 
 
 To be sure of the Ashby reaction, it is well to add a 
 little H 2 SO 4 to vinegar of known purity and compare the 
 result with the residue under examination. 
 
 To detect Sulfuric Acid in the Presence of Natural Sulfates 
 of the Vinegar. Evaporate 100 cc. of the sample to one tenth 
 of its volume, and when cold add 50 cc. of alcohol. Sulfuric 
 acid remains in solution while the natural sulfates are pre- 
 cipitated. Dilute the solution and precipitate the H 2 SO 4 
 with BaCl 2 . Write the reaction. 
 
 Detection of Caramel. Caramel, or burned sugar, is some- 
 times used to make the vinegar seem stronger than it really 
 is, or to make it resemble cider vinegar. Shake 5 cc. of the 
 sample with twice its volume of amyl alcohol. If caramel 
 is present, the supernatant layer will be wholly or par- 
 tially decolorized. The under layer will be a deep brown, 
 depending upon the amount of caramel present. 
 
 Detection of Coal-Tar Dye. Use the double-dyeing process 
 of Sostegni and Carpentieri, q.v. 
 
 To distinguish Cider Vinegar from Other Vinegars. Lyth- 
 goe's Method. Prepare lead subacetate solution by dissolv- 
 ing 180 g. of lead acetate in half a liter of water. Add 
 110 g. of PbO and make up to 1000 g. with water. Agitate 
 often and filter. 
 
 To 25 cc. of the vinegar add 2.5 cc. of the subacetate 
 solution. Shake the contents of the tube. The precipitate 
 should be copious and settle out in a few minutes. 
 
24 
 
 ELEMENTARY APPLIED CHEMISTEY 
 
 For comparative results, centrifuge in a graduated tube 
 and read the volume of the precipitate. The amount 
 present, in part at least, indicates the value of the vinegar. 
 
 Unless a precipitate is formed the 
 sample is not cider vinegar. 
 
 Determination of the Approximate 
 Acidity or Alkalinity of Soils. Boil 
 exactly 10 g. of thoroughly dried 
 soil in 30 cc. of water. Filter and 
 wash the residue several times with 
 small portions of hot water. Add the 
 washings to the filtrate with two or 
 three drops of phenolphthalein. If 
 the reaction is alkaline, titrate with 
 N/10 oxalic aeid until the pink color 
 is destroyed by addition of the last 
 drop. 
 
 Hlf the reaction is acid, titrate with 
 N/10 NaOH until the first tinge of 
 pink appears. 
 
 In either case express the result 
 as the number of cubic centimeters of 
 the N/10 solution required to neu- 
 tralize the nitrate. 
 
 Approximation of the Purity of 
 Cocoa. The purity of cocoa can, in 
 part at least, be determined by cal- 
 culating the per cent of its ash, which in pure samples 
 seldom exceeds 5.5 per cent; and under ordinary condi- 
 tions the ash from each gram of the sample will require 
 not more than 3.7 cc. of N/10 oxalic acid to neutralize it. 
 If possible, test samples from your home. 
 
 FIG. 6. True and artifi- 
 cial vinegar treated with 
 lead subacetate 
 
 The artificial vinegar, on 
 
 the right, shows little or 
 
 no effect 
 
EXERCISES WITH STANDARD SOLUTIONS 25 
 
 Burn 2 g. of the sample to a carbon-free ash at the 
 lowest possible heat. Cool the crucible and calculate the 
 per cent of ash. Boil the contents of the crucible in 50 cc. 
 of water, being sure to rinse it well and save the washings. 
 Titrate with N/10 oxalic acid, using phenolphthalein as 
 an indicator. 
 
 Analysis of Soap. Insoluble Matter. Dissolve 5 g. of the 
 sample in 75 cc. of water, heating if necessary. If there 
 are more than mere traces of residue, filter on a tared filter 
 paper, wash with hot water until the filtrate is neutral, dry 
 at 105 C., and calculate the per cent. 
 
 Test various " hand " and scouring soaps for insoluble 
 matter. 
 
 Alkali may exist in soap in at least three forms, free, 
 combined, and as alkaline carbonates, borates, etc. 
 
 Detection of Free Alkali. Treat the freshly cut surface 
 of the soap with a few drops of the alcoholic solution of 
 phenolphthalein. If no red color appears, it may be assumed 
 that free alkali js absent. Take great care that no water 
 comes in contact with the soap, otherwise the results may 
 be misleading. 
 
 When testing washing powders for free alkali, dissolve a 
 small quantity in alcohol and add the phenolphthalein. 
 
 Combined Alkali. If free alkali, alkaline carbonates, bo- 
 rates, etc. are absent, dissolve a gram of the soap in 20 cc. 
 of hot water. Treat with phenolphthalein. A red color is 
 immediately seen. Why ? 
 
 Titrate with N/10 oxalic acid. Allow the acid to drop 
 slowly from the burette until the last drop added destroys the 
 pink color. Shake or stir the solution frequently during the 
 operation and be sure to waste none. If after a minute 
 the pink color reappears, add another drop of the acid. 
 
26 ELEMENTARY APPLIED CHEMISTRY 
 
 Free alkali may also be estimated by dissolving it 
 from 1 g. of the soap by means of alcohol. Filter, wash 
 with alcohol, and titrate as for combined alkali. Calcu- 
 late as NaOH. 
 
 CALCULATION FOR FREE OR COMBINED ALKALI 
 
 1 cc. of N/10 oxalic acid neutralizes 1 cc. of N/10 NaOH, or 0.004 g. 
 of NaOH. Suppose the number of cubic centimeters of acid required 
 is 4.75 ; then the per cent of alkali present is 4.75 x .004 = .019, 
 or 1.9 per cent. 
 
 Write the reaction between oxalic acid and sodium 
 hydrate. 
 
 Total Alkali. If the soap is free from sand and other 
 mineral matters, burn 2 g. to ash in a porcelain or quartz 
 crucible. Cool and wash the contents into 50 cc. of water. 
 Boil and titrate with N/10 oxalic acid, using two drops 
 of methyl orange as an indicator. (Dissolve 1 g. of methyl 
 orange in 1 liter of water.) 
 
 Express the result as the acid number ; that is, the num- 
 ber of cubic centimeters of decinormal acid necessary to 
 neutralize the alkali in 1 g. of the soap. 
 
 Alkaline Carbonates. Place 5 g. of the soap in an Erlen- 
 meyer flask and add 20 cc. of alcohol. Set a funnel in the 
 neck of the flask to act as a reflux condenser, and heat on a 
 water bath for ten minutes. Alkaline carbonates will be in 
 the residue. Place a bit of this residue on a clean platinum 
 wire and apply the flame test for sodium and potassium 
 (see under Soil Analysis). Filter the alcohol and dis- 
 solve the residue in warm water. Add a few drops of 
 dilute HC1. A marked effervescence indicates the presence 
 of carbonates ; whether Na 2 CO g (washing soda) or K 2 CO 8 
 (potash) will be indicated by the flame test. 
 
EXERCISES WITH STANDARD SOLUTIONS 27 
 
 Berates. Place 5 cc. of turmeric tincture in a watch 
 glass. Add a few drops of the soap dissolved in water, and 
 acidify slightly with dilute HC1. Evaporate to dryness over 
 a water bath. The presence of borates is indicated by the 
 pronounced reddening of the dried residue. 
 
 Record the results of your analysis in this form : 
 
 SAMPLE 
 
 PER CENT 
 INSOLUBLE 
 MATTER 
 
 PER CENT 
 FREE ALKALI 
 
 PER CENT 
 COMBINED 
 ALKALI 
 
 CARBONATES 
 
 BORATES 
 
 
 
 
 
 
 
SECTION VII 
 SANITARY ANALYSIS OF WATER 
 
 The importance of wholesome water cannot be overesti- 
 mated. Do the barns, the sinks, the outbuildings, contami- 
 nate the supply ? Does the water dissolve poisonous metals 
 from the pipes or other sources ? Is the water hard or soft ? 
 All these questions we shall be able to answer. 
 
 Clear, sparkling, odorless water may be totally unfit for 
 domestic purposes, while a suspicious-looking or peculiar- 
 smelling sample may be quite harmless. A simple chemical 
 analysis is often of great value, except in the detection 
 of specific disease germs, when an intelligent bacteriologi- 
 cal examination is necessary. The analysis in this case, 
 however, may throw much light upon the source of the 
 contamination. 
 
 Keep carefully tabulated results of your analyses. You 
 can then see at a glance how the water varies from the 
 normal. 
 
 Sediment. Allow a test tube or conical glass full of the 
 water to stand overnight, or centrifuge 10 cc. in a pointed 
 tube. If any sediment falls, decant the liquid and exam- 
 ine the deposit under a microscope. This deposit may be 
 divided into two classes, harmless and suspicious matter: 
 harmless matter, sand, clay, alga, diatoms; suspicious matter, 
 hair, epithelial scales, bits of wool and cotton, muscle fibers, etc. 
 
 Filter the remainder of the original sample before making 
 further tests. 
 
 28 
 
SANITARY ANALYSIS OF WATER 
 
 29 
 
 Color. Fill a clean test tube, the longer the better, with 
 the water, or use a Nessler tube. Stand it on a white 
 paper or tile, facing a good light. Cover the back of the 
 tube, except an inch at the bottom, with a piece of white 
 paper. On looking down through the tube the water should 
 be perfectly transparent, or show only a faint bluish tinge. 
 Pollution is indicated by tints 
 of green, yellow, or brown. 
 
 Odor. Warm about 250 cc. 
 of the water to 38 C. in a 
 corked flask. Shake, remove 
 the stopper, and smell the con- 
 tents. Pure water is free from 
 odor. The odor may be classi- 
 fied as earthy, vegetable, alka- 
 line, putrid, etc. 
 
 A putrid odor indicates de- 
 composing animal or vegetable 
 matter. If much polluted by 
 fresh sewage, the odor of urine 
 is not infrequent. One should 
 note that many waters unfit to 
 drink have no odor. A positive 
 odor teaches volumes ; a nega- 
 tive result is of little value. 
 
 Total Solids. These consist 
 for the most part of CaCO 3 , MgSO 4 , CaSO 4 with their 
 chlorids and nitrates, NaCl, SiO 2 , and organic matter. 
 
 Evaporate 70 cc. of the water to dryness in a thin, 
 counterpoised evaporating dish over a water or steam bath. 
 Dry, cool in a desiccator, and weigh as milligrams. Every 
 milligram of solids per 70 cc. represents one grain per gallon 
 
 FIG. 6. A convenient rack for 
 Nessler tubes 
 
 The movable mirror shows at an 
 angle 
 
30 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 in the original sample. Total solids in good water may be 
 as high as 30 grains per gallon. 
 
 Save the residue and examine for phosphates. The resi- 
 due from pure water is almost white. Iron gives a yellow 
 
 or coppery luster to the sides 
 of the dish. 
 
 Evaporate about 50 cc. of 
 the sample in a porcelain 
 evaporating dish and heat 
 gently at first. Charring de- 
 notes the presence of organic 
 matter. 
 
 Determination of ChloriaJes 
 Measure 50 cc. of the water 
 with a pipette into each of 
 two small flasks or beakers. 
 Add three or four drops 
 of potassium chromate solu- 
 tion, 10 per cent, as an indi- 
 cator, coloring the contents 
 of each flask exactly alike. 
 Place both flasks on a white 
 tile in a good light. Titrate 
 the water in one of the flasks 
 with a standard silver solu- 
 tion. Do not add more than a drop at a time. Continue 
 the titration with frequent agitation of the contents until 
 the water shows the first tinge of red. The first trace is 
 best seen by looking at the titrated sample through the 
 colored water in the control flask. 
 
 The number of cubic centimeters of the silver solution 
 required to produce the red tinge equals the number of 
 
 FIG. 7. Apparatus for the determi- 
 nation of chlorin in water 
 Control flask on the left 
 
SANITAEY ANALYSIS OF WATEK 31 
 
 parts of chlorin in 100,000 parts of water. If the water 
 contains more than five parts of chlorin per 100,000, con- 
 tamination from human urine or sink drains is to be sus- 
 pected, unless the water is taken near the seacoast or from 
 some locality where the normal sodium chloric! content 
 is above this amount. This information can usually be 
 obtained from any state board of health. 
 
 Write the reaction between silver nitrate and potassium 
 chromate. 
 
 The standard silver solution is prepared by dissolving 2.3944 g. of 
 pure AgNO 3 in a liter of distilled water. Keep this solution in a 
 yellow or black bottle away from the light. 
 
 Detection of Ammonia. To-gOTcc. of the water in a Nesslei 
 tube, tall test tube, or foot tube, adcljjfcc. of Nessler's^ 
 reagent and note the color. A faint yellow tinge only 
 should be visible. A deeper color or turbidity indicates 
 animal contamination. 
 
 Compare the treated water with an equal volume of the 
 untreated sample in a similar tube. 
 
 The experiment may be made quantitative by comparing 
 the color of the sample with different Nesslerizec! samples of 
 distilled water which contain known quantities of NH 4 C1. 
 
 All natural waters contain a trace of ammonia, but the 
 amount present should not be sufficient to cause more than 
 a slight coloration with the Nessler solution. An excep- 
 tion must be made in the case of rain water, which, although 
 relatively pure, contains a considerable amount of ammonia 
 dissolved from the atmosphere. Rain water, however, shows 
 practically no nitrates or chlorin. 
 
 Nessler's Reagent. Dissolve 62.5 g. of KI in 250 cc. of water. Re- 
 serve about 10 cc. of this solution. Run into the remainder a cold, 
 saturated solution of HgCl a until a permanent precipitate forms. 
 
32 ELEMENTARY APPLIED CHEMISTRY 
 
 Redissolve this precipitate by means of the reserve KI solution. 
 Very cautiously add more of the mercuric chlorid solution until a 
 slight precipitate remains after agitation. Add 150 g. of KOH in 
 water and make up to a liter. 
 
 Allow the precipitate to settle and decant or siphon off the clear 
 liquid. This solution improves with age. 
 
 Detection of Nitrites. Into a Nessler tube place a drop of 
 HC1, 2 cc. of sulfanilic acid, an equal volume of naphthyl- 
 amine hydrochlorid, and 50 cc. of the water under exami- 
 nation. If a red color is produced immediately or within 
 twenty minutes, the presence of nitrites is assured. 
 
 As a rule nitrites are never found in good water. 
 
 Sulfanilic Solution. Dissolve 0.8 g. of the acid in 100 cc. of pure 
 water, heating if necessary. 
 
 Naphthylamine Hydrochlorid Solution. Dissolve 0.8 g. of the salt 
 in 100 cc. of hot water to which 1 cc. of HC1 has been added. Filter 
 through bone black or add bone black to the solution, and decant as 
 needed. Keep from the light. 
 
 Detection of Nitrates. Evaporate 100 cc. of the sample 
 to dryness in a white evaporating dish over a water or 
 steam bath. Treat with 1 cc. of phenol-sulfonic acid, stir- 
 ring thoroughly. Add 10 cc. of distilled water and half 
 as much NH 4 OH. 
 
 In the presence of nitrates the characteristic yellow color 
 of the ammonia salt of nitrophenol-sulfonic acid is formed. 
 
 Nitrates are present in almost all natural terrestrial waters. 
 
 Detection of Phosphates. Evaporate 70 cc. of the sample 
 to dryness or use the residue from the determination of total 
 solids. Add a few drops of ammonia molybdate in nitric 
 acid and warm gently. There should be only a slight lemon- 
 yellow coloration. A decided yellow coloration indicates 
 animal pollution. The degree of intensity is sometimes 
 recorded as traces, heavy traces, and very heavy traces. 
 
SANITARY ANALYSIS OF WATER 33 
 
 Ammonium Molybdate Solution. Dissolve 15 g. of ammonium molyb- 
 date in 100 cc. of water, with the addition of a little ammonia if neces- 
 sary. If there is pronounced turbidity, filter the solution and pour with 
 constant stirring into a mixture of 50 cc. nitric acid and an equal vol- 
 ume of water. Allow the solution to stand in a warm place for several 
 days at a temperature of about 80 F. and decant the clear liquid. 
 
 ^ - ^yV^V^V^T'C/Jv-*v-^^* 
 
 Determination of AUflgrtog* ' Oxygen. This test gives 
 reliable information concerning the amount of organic 
 contamination, but does not distinguish between that of 
 animal and vegetable origin. 
 
 If more than one grain per gallon is absorbed, the water 
 is probably polluted. 
 
 Preliminary Test. Fill two test tubes half full, one with 
 S&nted water, the other with the sample. To each add a 
 drop of strong H 2 SO 4 and sufficient KMnO 4 in distilled 
 water to color each a very light purple, as nearly alike 
 as possible. Boil the contents of each tube. What is the 
 action of organic matter on KMnO 4 ? 
 
 Regular Test. Prepare a standard solution of KMnO 4 , 
 0.395 g. per liter, and keep in a clean well-stoppered bottle. 
 
 Place exactly 70 cc. of the water to be examined in a 
 clean flask and add ten drops of 10 per cent H 2 SO 4 . Warm 
 gently and add the standard solution from a burette, drop 
 by drop, shaking the flask gently after the addition of each 
 drop. As soon as the faintest tinge of pink appears, warm 
 the flask again and notice whether the color is permanent. 
 If not, add another drop. The first permanent tinge of pink 
 indicates the end of the operation. 
 
 Limit the test to fifteen minutes. Use an ordinary Bohe- 
 mian flask. 
 
 When 70 cc. of water is thus titrated, each cubic centi- 
 meter of the permanganate solution represents 0.1 of a grain 
 per gallon. Good water absorbs less than a grain per gallon. 
 
34 ELEMENTARY APPLIED CHEMISTRY 
 
 Metallic Compounds. Lead. Evaporate 100 cc. of the 
 sample to 20 cc. and add a few drops of K 2 O 2 O 7 . A pre- 
 cipitate of chrome yellow assures the presence of lead. 
 
 Iron and Copper. Boil 2 g. of stearic acid for five minutes 
 in 30 cc. of the suspected water. Set aside, and when 
 cool compare its color with a sample of the acid that has 
 been boiled for the same length of time in distilled water. 
 Examine before a white background. Iron salts impart a 
 yellow color. If traces of copper are present, the acid will 
 be colored a bluish green, which can be seen even before 
 the acid has solidified. 
 
 Hardness. Titrate 100 cc. of the water with N/10 HC1, 
 using methyl orange or erythrosin as an indicator. The 
 number of cubic centimeters of the decinormal acid used, 
 multiplied by 50, represents the number of parts of CaCO 3 
 per million parts of water. Calculate the results to parts 
 per 100,000. Water is considered "hard" if it contains 
 over five parts of CaCO 8 per 100,000. 
 
SECTION VIII 
 EXAMINATION OF BAKING POWDER 
 
 All baking powders leave a more or less insoluble resi- 
 due in the food which they are used to leaven. What salts 
 does one take into his system when he eats cake or biscuit 
 made with cream of tartar, with alum, or with phosphate 
 baking powder ? The following reactions are of interest : 
 
 KINO OF BAKING REACTIONS 
 
 POWDEll 
 
 Cream of tartar 
 
 Alum 
 
 Phosphate . . 
 
 CO 2 + TT,O 
 
 Potassium bitartrate Rochelle salts 
 
 K 2 A1 2 (SO 4 ) 4 + 6 HNaC0 3 = A1 2 (OH) 6 + 3Na 2 S0 4 
 
 Burnt alum Glauber's salts 
 
 H 4 Ca(P0 4 ) 2 + 2 HNaC0 3 = HCaP0 4 + HNaP0 4 
 Ca + 2C0 + 2H0 
 
 Determination of Carbon Dioxid. The value of a baking 
 powder, in part at least, depends upon the amount of avail- 
 able CO 2 it contains. To determine this, two separate tests 
 are necessary. 
 
 Total Carbon Dioxid. This determination consists of lib- 
 erating the CO 2 from a weighed amount of the sample, 
 passing the gas through caustic potash, and ascertaining 
 the increase in weight. Into an Erlenmeyer flask of about 
 150 cc. capacity weigh exactly 2 g. of baking-powder. 
 Fit the flask with a dropping funnel and a delivery tube 
 inclined upward at an angle of about 20. To the free 
 
 35 
 
36 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 end of the delivery tube attach a drying tube filled with 
 granulated CaCl 2 previously saturated with CO a . 
 
 Fill a set of Liebig potash bulbs two thirds full of a 
 solution of 1 part KOH and 2 parts water. Determine 
 the exact weight of the prepared bulbs by suspending from 
 
 FIG. 8. Apparatus for the determination of carbon dioxid 
 
 one arm of the balance. This done, connect the inlet of the 
 bulbs with the free end of the drying tube, and the outer 
 end with an aspirator. 
 
 Fill the dropping funnel half full of HC1 (sp. gr. 1.1). 
 
 Place a small drying tube filled with soda lime in the 
 mouth of the funnel, to prevent any CO 2 from the air 
 
EXAMINATION OF BAKING POWDER 37 
 
 being drawn into the potash bulbs when the aspirator is 
 in operation. 
 
 Open the funnel slightly and allow the acid to drop slowly 
 upon the sample. Adjust the aspirator so that the gas will 
 be drawn through the potash bulbs at the rate of about two 
 bubbles per second. When nearly all the acid has been 
 added, heat the contents of the generating flask to boiling, 
 until the water begins to condense in the delivery tube. 
 
 Aspirate until the potash bulbs are cool; then discon- 
 nect and reweigh. The increased weight is due to total 
 carbon dioxid. 
 
 Write the reaction between HC1 and baking soda. Is the 
 absorption of CO 2 by KOH due to physical or chemical 
 change ? 
 
 Residual Carbon Dioxid. Thoroughly clean the apparatus 
 used in the determination of total carbon dioxid. Intro- 
 duce 2 g. of the sample into the generating flask and add 
 20 cc. of cold water. Allow it to stand for twenty minutes. 
 Then set the flask into a tin can surrounded by boiling 
 water for the same length of time. Drive off the last traces 
 of gas in the pasty mixture by boiling for one minute. 
 Aspirate until the air is thoroughly changed. At this 
 point in the experiment connect the apparatus and perform 
 the work exactly as for the determination of total carbon 
 dioxid. The increase of weight in the potash bulbs is due 
 to the residual carbon dioxid. 
 
 Available Carbon Dioxid. From the per cent of total carbon 
 dioxid subtract the per cent of residual carbon dioxid. 
 
 The average per cent of available carbon dioxid found in 
 the three principal kinds of baking powder is as follows : 
 cream of tartar, 12.58; phosphate, 12.86; alum, 8.10 (Bulle- 
 tin No. 13, United States Bureau of Chemistry). 
 
38 ELEMENTARY APPLIED CHEMISTRY 
 
 Tests for Radicals found in Baking Powder. Chlorids. 
 Shake 2 to 4 g. of the sample with 25 cc. of cold water. 
 Filter. This constitutes a cold-water extract. To 5 cc. of 
 this extract add a few drops of 10 per cent AgNO 3 solu- 
 tion. If a precipitate forms, agitate and allow it to settle. 
 If it is insoluble in hot water, but dissolves in ammonia, 
 the presence of chlorids is indicated. 
 
 AgNO 3 + XC1 - ? AgCl + NH 4 OH = ? 
 
 Sulfates. Treat a few cubic centimeters of the cold-water 
 extract with barium chlorid solution. A precipitate insolu- 
 ble in acids and in water assures the presence of sulfates. 
 XSO 4 4- BaCl 2 = ? 
 
 Tartrates. Dissolve a crystal of silver nitrate in 5 cc. of 
 water and add two drops of ammonia. Add 1 cc. of the 
 cold-water extract and heat gently. If tartrates are present, 
 the silver will be deposited as a beautiful silver mirror on 
 the interior of the tube. 
 
 Carbonates. To a gram or so of the dry baking powder 
 in a test tube add a few drops of dilute II Cl. Hold a glass 
 rod wet with limewater so that the escaping gas will come 
 in contact with it. If the limewater becomes milky, the 
 presence of a carbonate is assured. 
 
 Write the reaction between hydrochloric acid and bicar- 
 bonate of soda. Write the reaction between carbon dioxid 
 and limewater. 
 
 Phosphates. Add a few drops of the cold-water extract to 
 a cubic centimeter of ammonium molybdate (NH 4 ) 2 MoO 4 in 
 HNO g . Heat gently. A lemon-yellow precipitate indicates 
 the presence of phosphates. 
 
 Phosphoric acid is an important constituent of the body. 
 Its presence can be easily demonstrated by experiment. 
 
L 
 
 ^Mal 
 
 EXAMINATION OF BAKING POWDER 39 
 
 Burn a piece of bone in a clear fire until the residue is 
 perfectly white. Powder from 2 to 3 g. of this and dissolve 
 in HC1. Dilute the solution about one half and add an ex- 
 cess of ammonia. A white, gelatinous precipitate of calcium 
 and magnesium phosphate forms. Filter, and to the filtrate 
 add ammonium oxalate. The characteristic precipitate of 
 CaC 2 O 4 is evident. 
 
 What other radical was present in the bone ? 
 
 Tests for Bases found in Baking Powder. Calcium. To a 
 test tube half full of the extract add a few drops of ammo- 
 nium oxalate (NH 4 ) 2 C 2 O 4 . A precipitate insoluble in acetic 
 acid, but soluble in 'hydrochloric acid, shows the presence 
 of calcium. 
 
 Write the reaction between ammonium oxalate and cal- 
 cium acid phosphate. 
 
 Ammonia. Boil 50 cc. of the extract with 25 cc. of 10 per 
 cent NaOH. Test the steam with red litmus paper. Avoid 
 touching the neck of the flask with the paper. If present, 
 the liberated ammonia will turn the test paper blue. 
 
 Write the reaction between ammonium carbonate and 
 sodium hydrate. 
 
 Aluminium. ( Thirty -first Report of the Massachusetts State 
 Board of Health.) Burn to ash about 2 g. of the baking pow- 
 der in a crucible. Extract with boiling water, and filter. 
 To the filtrate add sufficient NH 4 C1 to give a distinct odor 
 of ammonia. A flocculent precipitate indicates the presence 
 of aluminium. The lower grades of baking powder often 
 contain salts of aluminium or of ammonium. 
 
 Detection of Alum in Pastry as well as in Baking Powder. 
 
 ake a tincture of logwood by digesting 5 g. of the well- 
 powdered chips in 100 cc. of alcohol. Prepare a saturated 
 solution of (NH 4 ) 2 CO 3 . 
 
40 ELEMENTARY APPLIED CHEMISTRY 
 
 Rub 5 g. of the baking powder, cake, cooky, or biscuit 
 in a mortar with 10 cc. of water. Add 2 cc. of the logwood 
 mixture and an equal volume of the ammonium carbonate 
 solution. 
 
 If alum is present, the color changes to lavender or blue, 
 and does not disappear on boiling. If alum is not present, 
 the color varies from red to pink. 
 
SECTION IX 
 ANALYSIS OF MILK 
 
 More disease and fraud enter the home through the milk 
 supply than through any other article of food. Chemistry 
 is of untold benefit in protecting people from these evils. 
 
 What is the quality and condition of the milk which you 
 are using at home ? 
 
 Fat. Examine a drop of milk under a half -inch objective 
 and note the collection of various-sized fat globules. De- 
 scribe their appearance and arrangement. The fat of milk is 
 
 Prom CLEAN MILK From DIRTY MILK 
 
 COTTON PLUGS Prom FILTERED MILK. 
 
 FIG. 9 
 
 one of its most variable constituents, and the determination 
 of the amount present is of importance. 
 
 Determination of the Per Cent of Fat by the Babcock 
 Method. This method consists in adding strong sulfuric acid 
 to the milk to dissolve all of the solids except the fat, which 
 is afterwards separated by means of a centrifugal machine. 
 
 Measure exactly 17.6 cc. of the milk into a Babcock bottle 
 by means of a milk pipette. Add exactly 17.5 cc. of H 2 SO 4 , 
 
 41 
 
42 ELEMENTARY APPLIED CHEMISTRY 
 
 specific gravity 1.83 at 60 F., inclining the bottle so that 
 the acid will run in slowly and wash all adhering milk 
 from the neck. 
 
 Shake with a rotary motion so as to thoroughly mix 
 the acid and milk. Avoid getting curds into the neck 
 of the bottle. 
 
 If the work has been done properly, the mixture will be 
 a dark brown color and very hot. Place directly into a 
 centrifuge, arranging the bottle so that the rotating head 
 
 FIG. 10. Hand and electric centrifuges for milk analysis or for 
 sedimentation 
 
 will balance properly. If the machine vibrates badly, the 
 balance is not correct, and it must be adjusted. 
 
 Centrifuge for five minutes; then set the bottle into a 
 pan of hot water and add sufficient hot water to bring the 
 fat up to the neck of the bottle. 
 
 * Centrifuge for two minutes and add hot water sufficient 
 to bring the fat opposite the graduated scale. 
 
 Centrifuge for one minute and take the reading in tenths 
 of 1 per cent directly from the scale. 
 
 A pair of small dividers is useful for determining the 
 length of the fat column. This determined, place one leg of 
 
ANALYSIS OF MILK 
 
 43 
 
 the dividers upon zero and take the reading from the oppo- 
 site leg. It is customary to take the distance from the 
 bottom of the fat column to the top of its meniscus as 
 the true length. 
 
 The fat in milk varies from 2.2 per cent to 9.0 per 
 cent. The United States standard is 3.25 per cent. What 
 is the standard in your 
 state ? 
 
 Determination of Acid- 
 ity. Test both with red 
 and blue litmus paper. 
 Perfectly fresh cow's milk 
 is generally alkaline. It 
 is sometimes amphoteric, 
 that is, it exhibits the 
 phenomenon of reacting 
 alkaline with red litmus 
 and acid with blue. The 
 acidity increases as the 
 milk sugar is converted 
 into lactic acid. 
 
 For quantitative deter- 
 mination of lactic acid, 
 see page 20. 
 
 Specific Gravity. De- 
 termine with a lactometer, specific-gravity flask, or West- 
 phal balance. Milk of good standard quality should have 
 a specific gravity of 1.027-1.033 at 60 F. 
 
 Milk whose specific gravity varies from these limits is 
 of a suspicious character. 
 
 Total Solids, by Evaporation. Heat 2 g. of milk to a con- 
 stant weight in a counterpoised dish over a water bath. 
 
 FIG. 11. Babcock bottles for milk and 
 cream with dividers to facilitate reading 
 
44 ELEMENTARY APPLIED CHEMISTRY 
 
 The residue of milk must not be heated 
 over 100 C., as it will decompose and 
 lose weight almost indefinitely. If prop- 
 erly heated, the dried residue will be almost 
 white. 
 
 Total Solids, by Richmond* s Slide Rule. 
 This method is by far the more conven- 
 ient, and accurate enough for all practical 
 purposes. 
 
 Take the temperature of the milk and 
 the lactometer reading. Set this reading on I 3 
 
 the slide opposite the observed temperature. 
 The corrected reading will be found oppo- 
 site 60 on the scale. Call this reading A. I . 
 
 Place the arrow at the right-hand end of 
 the slide, opposite the per cent of fat found | 
 by the Babcock method. Find A on the 
 opposite edge of the slide. It will coincide 
 with the total solids in the milk. 
 
 The results obtained by these two methods 
 should agree closely. 
 
 Total solids should not be less than 12.50 
 per cent. 
 
 Tests for Foreign Matter, Dirt, Hair, etc. 
 Some of the most disagreeable as well as 
 dangerous kinds of foreign matter which 1 
 contaminate the milk supply enter through 
 the carelessness of the producer. 
 
 Construct a percolator by cutting the bot- 
 tom from a pint bottle, or use an ordinary 
 glass percolator employed by a druggist. 
 Insert a plug of clean absorbent cotton in 
 
ANALYSIS OF MILK 
 
 45 
 
 the neck from the inside, and allow a half pint or more of 
 the well-shaken milk to slowly filter through. Remove the 
 plug carefully and examine (see p. 41). 
 
 Insoluble matter, if present, can easily be seen. Wash 
 the clean end of the plug gently with cold water. Dry and 
 mount on cardboard with an appro- 
 priate inscription. 
 
 Tests for Adulterants : Artificial 
 Colors. Coloring matter is some- 
 times added to milk to give it a 
 rich, creamy appearance. The prac- 
 tice, if not absolutely injurious, is 
 at least reprehensible. Why ? 
 
 The two most commonly em- 
 ployed colors are annatto and coal- 
 tar dye. 
 
 Detection of Annatto. Shake 
 about 5 cc. of the milk with twice 
 its volume of ether in a large test 
 tube. When the liquids have sepa- 
 rated, pour off the ether extract. 
 Evaporate on a water bath. Make 
 the residue alkaline with NaOH 
 and pour 011 a small wet filter 
 paper. The annatto will be ab- 
 sorbed by the pores of the paper. 
 
 Wash off the fat gently with slightly warmed water. 
 Annatto will give a decided orange tone, which turns to 
 pink when treated with a few drops of stannous chlorid. 
 
 Detection of Coal-Tar Dye. To 10 cc. of the milk add 
 an equal volume of HC1 and mix thoroughly. A pink 
 coloration indicates the presence of azo orange. 
 
 FIG. 13. Percolating milk, 
 
 for dirt and other foreign 
 
 matter 
 
46 ELEMENTARY APPLIED CHEMISTRY 
 
 Tests for Adulterants : Preservatives. The .preservatives 
 most commonly employed to keep milk sweet for a longer 
 time than nature intended are formaldehyde, compounds 
 of boron (borax and boric acid), sodium bicarbonate, and 
 calcium sucrate. 
 
 Detection of Formaldehyde (HCHO). This is one of the 
 most poisonous of preservatives found in foods, and when 
 so used cannot be too strongly condemned. 
 
 Leach's Casein Test. First Part. To 10 cc. of pure milk 
 add an equal volume of hydrochloric acid, containing about 
 1 per cent of Fe 2 Cl 6 . Use an evaporating dish or casserole 
 and heat slowly, stirring or shaking the contents constantly 
 to break up the curd. When nearly but not quite boiling, 
 remove the heat and note the color of the treated milk when 
 hot and when cold. 
 
 Second Part. To 50 cc. of water add 1 cc. of HCHO 
 and mix the liquids well. Add two drops of this dilute 
 formaldehyde to 10 cc. of pure milk and perform the work 
 as directed under the first part. 
 
 How is the presence of formaldehyde indicated? I low 
 much was in the milk, assuming that the cubic centimeter 
 added to the water contained 40 per cent formaldehyde ? 
 
 The work under the first and second parts is' designed to 
 make the pupil familiar with the appearance of milk which 
 contains and which does not contain formaldehyde, when 
 the samples are treated with hydrochloric acid containing 
 a small percentage of ferric chlorid. 
 
 To test any given sample of milk, proceed as directed 
 under the first part, and if the results are similar to those 
 obtained under the second part, the presence of formalde- 
 hyde is indicated. Both this and the following . test are 
 exceedingly delicate and the results are thoroughly reliable. 
 
ANALYSIS OF MILK 47 
 
 Detection of ECHO by means of Hehner's Ring. To 25 vol- 
 umes of H 2 SO 4 add 1 volume of ferric chlorid solution. 
 Place 4 cc. of this reagent in a large test tube and carefully 
 add 5 cc. of the suspected milk, inclining the tube so that 
 the milk shall rest upon the surface of the acid. In the 
 presence of formaldehyde a violet ring is seen at the contact 
 of the two liquids. 
 
 Detection of Boron Compounds. First Part. Place 5 cc. 
 of pure milk in a watch glass and acidulate slightly with 
 10 per cent HC1. Add five drops of turmeric tincture and 
 evaporate to dryness over a water bath. What is the 
 appearance of pure milk thus treated ? 
 
 Second Part. To 5 cc. of the milk add a drop of boric acid 
 or borax dissolved in a little water. Transfer to a watch glass 
 and proceed as before. Take care that the mixture does not 
 char. How is boron indicated ? The reaction is said to be 
 sensitive to 1 part of boric acid in 25,000 parts of milk. The 
 red color is proportionate to the amount of boron present. 
 
 Test unknown samples of milk, performing the work as 
 outlined under the first part. If the sample of milk is very 
 rich, or if cream is under examination, dilute with two or 
 three volumes of water. 
 
 Turmeric Tincture, U.S. P. Digest any convenient amount of 
 ground turmeric root in small quantities of water, discarding the 
 liquids. Digest the dried residue with six times its weight of alcohol, 
 and filter. 
 
 Detection of Bicarbonate of Soda. The ash of pure milk 
 shows no effervescence with HC1. Burn 10 cc. of milk to 
 a white ash in a porcelain or quartz crucible over a low 
 flame. Treat the ash with a drop of 10 per cent HC1. An 
 effervescence indicates bicarbonate of sodium. 
 
 HNaC0 8 +2HCl = ? 
 
48 ELEMENTARY APPLIED CHEMISTRY 
 
 Detection of Calcium Sucrate. This substance is used as 
 a thickener as well as a preservative, and is more frequently 
 found in cream than in milk. It may be readily detected by 
 means of the Baier and Neumann test which follows : 
 
 First Part, the Sugar. To 25 cc. of the milk or cream add 
 10 cc. of a 5 per cent solution of uranium acetate. Shake 
 and allow to stand for five minutes. 
 
 Filter ; if the filtrate is not clear, pour it through again. 
 To 10 cc. of the clear filtrate (if the sample is cream, 
 use the total filtrate) add 2 cc. of a cold saturated solu- 
 tion of ammonium molybdate freshly prepared and 8 cc. of 
 dilute HC1 (1 part of 25 per cent HC1 and 8 parts of 
 water). Agitate the mixture well and place the small flask 
 containing it in a water bath at 80 C. for ten minutes. 
 
 If the sample is pure, the solution will be a peculiar 
 green, resembling nickel sulfate solution ; but if sugar is 
 present, it will be a Prussian blue color. 
 
 Second Part, the Calcium. Evaporate 25 cc. of the milk 
 or cream to dryness and burn to ash in a muffle. Dissolve 
 the ash in 20 cc. of N/10 H 2 SO 4 . Boil to expel the CO 2 and 
 titrate back with N/10 NaOH, using phenolphthalein as 
 the indicator. 
 
 Express the results as cubic centimeters of N/10 acid re- 
 quired to neutralize 100 g. of milk or cream. Suppose that 
 the ash was dissolved in 20 cc. of N/10 acid and that 14 cc. 
 N/10 NaOH neutralized the excess. It is evident that 6 cc. of 
 the acid was required to neutralize the alkalinity of the ash. 
 
 Detection of Gelatin in Milk, Cream, and Ice Cream. 
 This substance is sometimes used in cream, and more 
 frequently in ice cream, either as a thickener or to make 
 the material stand transportation better. Gelatin is readily 
 detected by the Stokes test. 
 
ANALYSIS OF MILK 
 
 49 
 
 Stokes's Test. To 10 cc. of the sample add an equal 
 volume of acid nitrate of mercury solution and 20 cc. of 
 cold water. Shake the mixture vigorously and allow it to 
 stand for five minutes. Filter; if gelatin is present, the 
 filtrate will be opalescent. Confirm by treating the filtrate 
 with 1 cc. of a saturated aqueous solution of picric acid. 
 The gelatin will be precipitated as a yellow solid, more or 
 less flocculent in appearance. 
 
 Acid Nitrate of Mercury Solution. Dissolve any convenient weight 
 of mercury in twice its weight of concentrated HNO 3 and dilute this 
 solution to 25 times its bulk with water. 
 
 Detection of Milk adulterated by Skimming and by 
 Watering. In order to do this work intelligently one must 
 become familiar with the principal factors employed in 
 calculations of this kind. These factors are: 
 
 Total solids : all the constituents of milk except water. 
 
 Fat. 
 
 Solids not fat: obtained by subtracting the fat content 
 from the total solids. 
 
 Proteins : the nitrogenous part of the milk. 
 
 Ash : the mineral constituents. 
 
 Milk sugar and lactose. 
 
 The following table, devised by H. C. Lythgoe, is believed 
 to show the limits between which normal milk varies : 
 
 
 Extreme limits 
 (per cent) 
 
 Usual limits 
 (per cent) 
 
 Herd milk 
 (per cent) 
 
 Total solids . . 
 
 10 17 
 
 10 5 16 
 
 11 8 15 
 
 Fat 
 Proteins 
 
 2.2 - 9.0 
 2.1 8.5 
 
 2.8- 7.0 
 25 45 
 
 3.2- 6.0 
 
 25 40 
 
 Ash . . ... 
 
 06 09 
 
 7 08 
 
 7 08 
 
 Solids not fat .... 
 Milk sugar 
 
 7.5- 11.0 
 4.0- 6.0 
 
 7.7 - 10.0 
 4.2- 5.5 
 
 8.0- 9.5 
 4.3- 5.3 
 
50 ELEMENTARY APPLIED CHEMISTRY 
 
 A relation has been found to exist between the fat and 
 proteins of milk. If the fat is given, the proteins may be 
 approximately calculated by means of Van Slyke's formula : 
 0.4 (F.- 3) +2.8 = P. 
 
 Suppose the fat found in a certain sample of milk is 
 3.50 per cent. According to the formula, the proteins are 
 3.0 per cent. 
 
 A relation also exists between the total solids and 
 proteins, which is expressed by Olsen as 
 T.S.-T.S/1.34 = P. 
 
 Suppose the solids in the sample mentioned above were 
 12.50 per cent. The proteins, by Olsen's formula, are 3.18 
 per cent. If the milk is pure, the per cent of proteins calcu- 
 lated by the two formulas will agree closely with a variation 
 of approximately 0.2 per cent or less. If the milk is adulter- 
 ated with water or by skimming, the results will not agree, 
 the difference increasing with the amount of adulteration. 
 
 Illustrations. A sample of milk known to be watered contained 
 3.4 per cent fat and 10.41 per cent of total solids. 
 
 Proteins calculated from the fat 2.96% 
 
 Proteins calculated from the solids .... 2.65% 
 Difference 31% 
 
 A sample of milk known to be skimmed contained 2 per cent fat 
 and 11.18 per cent of total solids. 
 
 Proteins calculated from the fat 2.40% 
 
 Proteins calculated from the solids .... 2.84% 
 Difference 44% 
 
 According to Lythgoe we may use these formulas in the 
 indirect calculation of milk sugar, if we assume the average 
 ash of milk to be 0.7 per cent. 
 
 T.S. - (F. + [0.4 (F. - 3) + 2.8] + 0.7) - Milk sugar. 
 T.S. - (F. + [T.S. - T.S./1.34] + 0.7) = Milk sugar. 
 
ANALYSIS OF MILK 51 
 
 Detection of Skimmed Milk. If the sample has been 
 skimmed, the calculated proteins will exceed the fat, and 
 the calculated milk sugar will be too high, exceeding 4.8 
 per cent, which is approximately the average milk sugar, 
 according to the table. 
 
 If the fat is less than 2.2 per cent and the solids not 
 fat are above 8.5 per cent, the milk has probably been 
 skimmed. 
 
 Detection of Added Water, Copper Sulfate Method. Since 
 there is no chemical test to distinguish between added 
 water and the water naturally present in milk, it is cus- 
 tomary to precipitate the fat and proteins by means of 
 acetic acid, copper sulfate, or by spontaneous souring. This 
 leaves the fat and protein in the curd, the milk sugar and 
 ash in the whey. 
 
 Dissolve 72.5 grains of pure crystallized CuSO 4 in a little water 
 and dilute to 1 liter. Adjust this to have a specific gravity of 1.0443 
 at 20 C. compared with water at 4C. 
 
 To 1 part of copper solution add 4 parts of sweet milk, 
 shake thoroughly, and filter. 
 
 If the specific gravity of the clear filtrate is less than 
 1.0245 at 20 C., compared with water at 4 C., added water 
 is indicated. 
 
 Dry 5 cc. of the copper serum to a constant weight over 
 a water bath. Determine the weight of the 5 cc. from the 
 specific gravity of the serum and calculate the total solids. 
 If the total solids are below 5.28 per cent, added water is 
 indicated. 
 
SECTION X 
 
 EXAMINATION OF ICE CKEAM, CHEESE, AND 
 CONDENSED MILK 
 
 Determination of the Fat in Ice Cream. Tare a Babcock 
 cream bottle and add 10 g. of the well-mixed sample 
 together with 5 or 6 cc. of water. Mix thoroughly and 
 add just enough sulfuric acid to turn the contents dark 
 brown. Avoid an excess of acid, as the mixture will char 
 badly. Proceed with the regular Babcock test. Multiply 
 the scale reading by 18 and divide by 10, to find the per 
 cent of fat. 
 
 The per cent of fat in ordinary cream is also found by 
 this method. 
 
 Starch. Boil a small quantity of the sample in a test 
 tube with 10 cc. of water. Cool, and add a few drops of 
 iodin tincture. The well-known blue color will be evident 
 if the sample contains starch. 
 
 If starch is present, place a drop of the sample on a 
 slide and examine with the microscope to see if you can 
 determine the kind. 
 
 Gelatin. Apply Stokes's test. 
 
 Fat in Cheese. Weigh 6g. of the sample in a tared beaker. 
 Add 10 cc. of boiling water and a few drops of ammonia. 
 Stir gently until a smooth emulsion is formed. Transfer 
 the contents to a Babcock cream bottle, cool slightly, and 
 add 17.6 cc. of H 2 SO 4 , first rinsing out the beaker with the 
 acid. Proceed with the regular Babcock test. 
 
 62 
 
ICE CKEAM, CHEESE, CONDENSED MILK 58 
 
 The fat reading on the scale multiplied by 18 and divided 
 by the weight of the sample (6 g.) gives the per cent of 
 fat in the cheese. 
 
 How can you distinguish a full-cream cheese from a 
 skimmed-milk cheese ? 
 
 Fat in Condensed Milk (Unsweetened). Weigh 6 g. of 
 the thoroughly mixed sample into a tared Babcock milk 
 bottle and add enough water to make the volume up to 
 about 17.6 cc. Mix, and add sufficient H 2 SO 4 to produce the 
 deep brown color required by the Babcock method. About 
 14 cc. of acid will be needed. Proceed with the regular 
 Babcock test. 
 
 Multiply the fat reading by 3, to find the correct per 
 cent of fat in the sample. 
 
 Number of Times Condensed and Fat in the Original Milk. 
 The average ash of pure milk is .70 per cent. Burn from 
 2 to 3 g. of the sample in a crucible and calculate the per 
 cent of ash. This per cent divided by .7 gives approximately 
 the number of times the milk has been condensed. 
 
 Divide the fat found by the Babcock method by the 
 number of times condensed, to find the fat in the original 
 sample. 
 
SECTION XI 
 DISTILLATION EXPERIMENTS 
 
 Prepare a solution of 2 g. of NaCl in 50 cc. of water. 
 Taste. Add a few cloves and a little sand, and color with 
 red ink or dye. Pour into a retort or distilling flask. Adjust 
 a suitable condenser and distil off about one half. 
 
 Examine both residue and distillate. What substances 
 are present in the distillate that were present in the original 
 mixture ? What kinds of substances are separated by distil- 
 lation ? What physical principle is involved ? What prac- 
 tical applications of distillation do you know of ? What is 
 fractional distillation ? 
 
 Extraction of Essential Oils. The odor and taste of many 
 vegetable substances is due, in large measure, to the presence 
 of a volatile compound known as essential oil. 
 
 What is the difference between fixed and essential oils ? 
 
 Extract the essential oil from wintergreen leaves, sweet 
 birch (Eetula lentulci), cloves, cinnamon, nutmeg, pepper- 
 mint, bay leaves, orange or lemon rind. 
 
 To obtain the greatest amount of oil from any of these 
 substances, grind through a meat chopper, add water to 
 make an extremely thin paste, and distil. At first the dis- 
 tillate will be of a milky appearance, due to the suspended 
 oil. Set aside until the liquid clears. 
 
 A second method for the extraction of essential oils, 
 which gives even better results than the first and removes 
 the liability of breaking the retort through the heavy 
 
 54 
 
DISTILLATION EXPERIMENTS 55 
 
 material sticking to the bottom, is to place the finely ground 
 mass in a dry flask fitted with a two-hole stopper and con- 
 nected with a condenser. Steam from a generating flask is 
 blown in through a long bent glass delivery tube, which 
 extends nearly to the bottom of the flask. 
 
 What is the use of essential oils ? What is the meaning 
 of " essence," " extract," and " tincture " ? How may essen- 
 tial oils be extracted except by distillation ? (See Harpers' 
 Monthly for November, 1906.) 
 
 Experiments with Alcohol. Few substances are of greater 
 industrial value than alcohol. Make a list of the uses of 
 alcohol, either ethyl (C 2 H 5 OH) or methyl (CH 3 OH), or 
 both. What is denatured alcohol ? 
 
 Usually from 5 to 8 per cent of grain alcohol is sufficient 
 to preserve the extractive principles of medicine. How do 
 you account for such high amounts as 28 to 44 per cent 
 sometimes present ? 
 
 Make a medicine tester. Cut a piece of quarter-inch 
 glass tubing 8 in. long. Smooth the ends. Push one end 
 through a one-hole rubber stopper. To the free end fit an 
 ordinary Welsbach burner and mantle. 
 
 Place two tablespoonfuls of the liquid under examina- 
 tion in a Bohemian flask and insert the stopper and tube. 
 Heat the flask gently, and if- alcohol is present in amounts 
 of over 12 per cent, it will cause the mantle to glow brightly 
 when ignited. 
 
 To get the best effect, inclose the mantle in a glass or 
 mica chimney. Some brands of "bitters," "tonics," "cures," 
 "specifics," etc. contain enough alcohol to keep up the 
 incandescence for five or six minutes. 
 
 Instead of the Bohemian flask one may substitute a cop- 
 per can fitted with a small screw stopper. Into the top of 
 
56 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 the can solder a piece of gas pipe about 8 in. long and fit 
 with a burner. Be sure that all connections are well made. 
 
 FIG. 14. Testing apparatus to demonstrate the presence of alcohol in 
 medicine and beverages 
 
 Preparation of Alcohol (C 2 H 5 OH). Dissolve 30 g. of cane 
 sugar in 75 cc. of water, add a drop of HC1, and boil one 
 
DISTILLATION EXPERIMENTS 57 
 
 minute. If grape sugar or 20 cc. of molasses is used instead 
 of cane sugar, the boiling and acid may be omitted. 
 
 Dissolve half a cake of yeast in the same volume of water 
 not above 50 C. Cool the sugar solution to about the same 
 temperature and mix with the yeast. Allow to remain in a 
 warm place for two or three days % and observe from time to 
 time any visible changes. 
 
 Decant the liquid into a retort and distil off about one 
 half. Wash the retort, pour in the distillate, and distil off 
 10 cc. Test the second distillate as follows : 
 
 Determine its odor and taste. In it test the solubility 
 of a bit of camphor or the oil from a piece of orange or 
 lemon peel. Burn a little in an evaporating dish. To 
 equal quantities of the distillate and acetic acid add a few 
 drops of H 2 SO 4 , taking care that the contents of the tube 
 do not spatter in your face. Heat gently. Notice the 
 ethereal, fruitlike odor of ethyl acetate, or acetic ether, a 
 substance much used in the preparation of artificial flavor- 
 ing compounds. 
 
 If the experiment has been conducted properly, the fer- 
 mented liquid will contain about 4.5 per cent of alcohol 
 by volume. 
 
 Cane sugar does not ferment. Treated properly with 
 acid the reaction probably takes place as follows: 
 
 C 12 H 22 O n + H 2 = C 6 H 12 6 + C 6 H 12 6 . 
 
 cane sugar glucose fructose 
 
 The instructor or one of the pupils should prepare a 
 flask of the sugar-yeast mixture. Fit a delivery tube so 
 that its free end dips below the surface of a few cubic cen- 
 timeters of limewater contained in a small, narrow-necked 
 
58 ELEMENTARY APPLIED CHEMISTRY 
 
 bottle. The presence of CO 2 , given off during the process 
 of fermentation, is thus easily demonstrated. 1 
 
 Determination of the Per Cent of Alcohol by Distillation. 
 The chemical and physical characteristics of alcohol are so 
 apparent that a qualitative analysis is seldom necessary. It 
 is highly important, however, to know how much of this 
 substance enters into the composition of various medicines 
 and articles intended for internal use. To comply with the 
 Food and Drugs Act, the amount of alcohol must be plainly 
 stated upon the label. How does your analysis agree with 
 the statement ? 
 
 Introduce exactly 100 cc. of sweet cider, beer, wine, medi- 
 cine, root-beer extracts, or any of the various " tonics " and 
 " blood purifiers," into a retort and distil off about one half, 
 being sure that the free end of the condenser dips deeply 
 into the receiving flask. Make up the distillate to exactly 
 100 cc. by adding distilled water. Determine the specific 
 gravity of the thoroughly mixed distillate, and from this 
 determine the per cent of alcohol by volume by means of 
 the tables (pp. 66-75). 
 
 Repeat the experiment by weighing exactly 100 g. of 
 the sample in a tared flask or beaker. Transfer to a retort 
 and distil as before. 
 
 Make the distillate up to 100 g. with distilled water. 
 Take the specific gravity. From this determine, by means 
 
 1 The student will find helpful references to alcohol in the following 
 publications : 
 
 Popular Science Monthly: "History of Alcohol," Vol. LI, p. 231; 
 "Physiology of Alcohol," Vol. L, p. 796; "Natural Production of Alco- 
 hol," Vol. XIX, p. 238; "Discovery and Distillation of Alcohol," Vol. 
 XLIII, p. 85; "Use of Alcohol in Medicine," Vol. XXXVIII, p. 86; 
 "Vinous Superstitions," Vol. XXIV, p. 234; "Pigs as Wine Bibbers," 
 Vol. XXIV, p. 426. 
 
 Farmers' Bulletin No. 268, United States Department of Agriculture. 
 
DISTILLATION EXPERIMENTS 
 
 59 
 
 \ 
 
 i 
 /I 
 
 of the tables, the per cent of alcohol by weight. Discover 
 any mathematical sequence in the alcohol tables (pp. 66~75). 
 
 Suggestions. Always carefully rinse the vessel contain- 
 ing the measured amount of the sample into the retort, 
 using about half its 
 volume of water. 
 
 Determine the tem- 
 perature of the dis- 
 tillate at which you 
 take the specific 
 gravity and correct 
 to 60 F. or 15 C. 
 For all temperatures 
 above these stand- 
 ards subtract .00080 
 for each Centigrade 
 degree or .00044 for 
 each Fahrenheit de- 
 gree. For all temper- 
 atures below these 
 standards the cor-' 
 rection is additive. 
 
 If, for this work, 
 pupils are encour- 
 aged to bring sam- 
 ples from home, the 
 results will often be 
 a revelation not only to themselves but also to their parents. 
 
 Determination of the Per Cent of Alcohol by Difference in 
 Specific Gravity. This method, suggested by Leach, gives 
 approximate results. Use the preceding method whenever 
 possible. 
 
 FIG. 15. Apparatus for determining the 
 per cent of alcohol 
 
60 ELEMENTAKY APPLIED CHEMISTKY 
 
 Determine the specific gravity of the original sample. 
 Evaporate 50 cc. over a water bath to one fourth its 
 .bulk. Make up to its original volume with distilled water. 
 Determine the specific gravity of this dealcoholized por- 
 tion. Add 1 to the original specific gravity and subtract the 
 second. The difference corresponds to the alcohol in the 
 original sample. 
 
 Consult the tables (pp. 66~75) as before and read the 
 per cent of alcohol by volume. 
 
 Methyl or Wood Alcohol (CH 3 OH). It is difficult to find a 
 more dangerous liquid used to cheapen food products and 
 medicinal preparations than methyl alcohol. It is responsi- 
 ble for many cases of death and blindness. It apparently 
 makes little difference whether it is taken internally in 
 medicines and beverages, rubbed on the skin as a liniment, 
 or its vapor inhaled ; death, severe illness, or blindness 
 may result. 1 
 
 In more instances than one this poison has been found, 
 in its deodorized form, in Jamaica ginger, lemon extract, 
 peppermint and cinnamon, " hot drops," liniments, bitters, 
 toilet waters, bay rum, witch hazel, spirits of camphor, 
 paregoric, whisky. 
 
 Detection of Methyl Alcohol. Except where a refractom- 
 eter is used, the presence of wood alcohol is proved indi- 
 rectly, usually by oxidizing it into formaldehyde. 
 
 Cut a piece of No. 14 copper wire 90 cm. -long. At a 
 point 20 cm. from one end wind the wire neatly around a 
 pencil into a close spiral until about 20 cm. from the oppo- 
 site end. Push the first end through the coil and twist 
 both together to form a handle. 
 
 1 For instances of methyl alcohol poisoning, see Journal of the Ameri- 
 can Medical Association, October 1-29, 1904. 
 
DISTILLATION EXPERIMENTS 61 
 
 Prepare a solution of 1 part CH 3 OH and 6 parts water. 
 Mix, and pour 10 cc. into a 5-in. test tube whose inside 
 diameter is a little greater than the diameter of the spiral. 
 Stand the tube in a bottle of cold water, to cool the contents 
 during the oxidizing process. 
 
 Heat the coil to a dull red in the upper Bunsen flame 
 and plunge immediately into the dilute alcohol. Withdraw 
 in a second and dip into water. Repeat the operation from 
 three to six times. This treatment will change all or a 
 part of the alcohol into formaldehyde. 
 
 CH OH - 2 H = HCHO. 
 
 o 
 
 CuO + 2 H = ? 
 
 What reaction takes place when the copper spiral is 
 heated in the upper Bunsen flame ? 
 
 Decant the oxidized liquid and divide into two portions. 
 Add one portion to a little milk ancl apply the tests for 
 formaldehyde. 
 
 To the other portion add 1 drop of 1 per cent resorcin 
 solution and mix well. Pour this mixture carefully down 
 the side of a wide test tube which contains a half inch of 
 concentrated H 2 SO 4 . A red ring (not brown) will form 
 between the two liquids. If much formaldehyde is present, 
 a precipitate may be seen. This is known as Hehner's 
 resorcin test. 
 
 Test witch hazel, lemon extract, cheap vanilla, etc. 
 by oxidizing 10 cc. as indicated. In the case of vanilla 
 it is advisable to distil off about 10 cc. and oxidize the 
 distillate. 
 
 Caution. One must always be sure that the original 
 sample does not contain formaldehyde before testing for 
 methyl alcohol, otherwise the results might be misleading. 
 
62 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 If there is a question, add a few drops of the original 
 sample to 5 cc. of milk and apply the Hehner test. 
 
 All aldehydes may be removed by distilling 50 cc. of the 
 sample with 10 g. of sodium bisulfite and allowing the mix- 
 ture to stand for two hours. Distil a second time, and make 
 
 distinctly alkaline 
 withNaOH. Oxidize 
 this distillate and 
 test for methyl alco- 
 hol (^Report Massa- 
 chusetts State Board 
 of Health, 1906, 
 p. 401). 
 
 Use of Alcohol in 
 the Preparation of 
 Vanilla Extract. The 
 preparation of fla- 
 voring extracts from 
 pure and high-grade 
 materials is a valu- 
 able experience for 
 students of chem- 
 istry. The work can 
 be done in the lab- 
 oratory or at home. 
 Vanilla extract is the flavoring extract prepared from 
 vanilla beans, with or without sugar or glycerin, and con- 
 tains in 100 cc. the soluble matters from not less than 
 10 g. of the beans (/". S.. standard). 
 
 Preparation (United States Pharmacopoeia). Cut 100 g. 
 of vanilla beans in a meat chopper, which must be clean 
 and free from foreign odors. Weigh 200 g. of coarse 
 
 FIG. 16. Copper spiral and water-cooled test 
 
 tube for the oxidation of methyl alcohol into 
 
 formaldehyde 
 
DISTILLATIOK EXPERIMENTS 63 
 
 granulated sugar; mix 650 cc. of alcohol with 350 cc. of 
 water. 
 
 Macerate the vanilla in 500 cc. of this dilute alcohol 
 for twelve hours ; then drain off the liquid and set it aside. 
 Transfer the vanilla to a mortar and beat it with the sugar. 
 Pack the mass into a percolator, the neck of which has 
 been plugged with a piece of absorbent cotton from within, 
 and pour on the reserved dilute alcohol. When this has 
 disappeared from the surface, gradually pour on the men- 
 struum and continue percolation until 1000 cc. have been 
 obtained. Repercolate several times. 
 
 Vanilla extract improves with age. If the alcoholic mix- 
 ture remains on the beans for several months, the flavor of 
 the extract will be improved. 
 
 To distinguish between True and Artificial Vanilla Extract. 
 Many of the so-called vanilla extracts contain little or no 
 vanilla, but are composed of a dilute alcoholic solution of 
 vanillin, or coumarin, prepared from coal tar. Sometimes 
 true coumarin, the aromatic principle of the tonka or 
 " snuff " bean, is added to make the flavor more pronounced 
 and lasting. Such extracts are often colored with caramel 
 or with coal-tar dye. 
 
 Some experience is necessary to distinguish between true 
 and artificial extracts by a sense of smell or taste alone, but 
 there are several chemical tests which will definitely settle 
 the matter. 
 
 By the Lead Acetate Precipitate. To 40 cc. of the sample 
 add an equal volume of normal lead acetate solution pre- 
 pared by dissolving 189.5 g. of Pb(C 2 H 3 O 2 ) 2 4- 3 H 2 O in 
 water and diluting to 1 liter. 
 
 The absence of a precipitate is conclusive evidence that 
 the extract is artificial. Pure vanilla thus treated yields a 
 
64 ELEMEKTAKY APPLIED CHEMISTRY 
 
 heavy precipitate which should settle in a few minutes, 
 leaving a clear, partially decolorized liquid (Leach). 
 
 By Examination of the Resins Present. Evaporate the alco- 
 hol from 50 cc. of the extract over a water bath and 
 make up to the original volume with water. If an alkali 
 (usually K 2 CO 3 ) 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, allow to stand for 
 a few minutes, and collect the resins on a filter paper. 
 Wash the residue twice with slightly warmed water. 
 
 Tear off a portion of the filter paper with the resins 
 attached, and place it in a few cubic centimeters of dilute 
 KOH. If the vanilla is pure, this resin will dissolve, making 
 a deep red solution. 
 
 Dissolve the rest of the resin in alcohol and divide the 
 solution into three parts: 
 
 (a) Add a few drops of ferric chlorid. There will be no 
 particular change if the vanilla is pure. 
 
 (b) Add a few drops of dilute HC1. If the vanilla is 
 pure, there will be no particular color change. 
 
 (c) Add a few drops of lead subacetate solution. If 
 the vanilla is pure, the precipitate will be so bulky as to 
 almost solidify. Its filtrate will be almost colorless (Bulletin 
 No. 107, revised). 
 
 Use of Alcohol in the Preparation of Lemon Extract. 
 Lemon extract is the flavoring extract prepared from the oil 
 of lemon or from lemon peel, or both, and contains not less 
 than 5 per cent by volume of lemon oil ( U. !S. standard). 
 
 An extract of fair quality, but which does not contain the 
 legal amount of lemon oil, may be prepared by grating the 
 yellow rind from six lemons and macerating in 40 per cent 
 alcohol for a few days. It can then be filtered and used. 
 
DISTILLATION EXPERIMENTS 65 
 
 A legal extract can be prepared by dissolving 1 oz. of 
 lemon oil in 19 oz. of alcohol. This extract can then be 
 colored, if desired, by the addition of some of the bright 
 yellow solution prepared from the lemon peel. 
 
 Approximate Test for Strength and Purity. To 50 cc. of 
 cold water add 2 cc. of the lemon extract. The oil will be 
 thrown out of solution, giving the top of the water column a 
 decided milky appearance. The depth of the milkiness, in a 
 measure, enables one to judge of the strength of the extract. 
 Absence of the milky color is conclusive proof that the 
 extract is artificial. If it is of a decided yellow color, test 
 for artificial color as directed under Coal-Tar Dye. 
 
 Per Cent of Lemon Oil. Mitchell's Test. Place 20 cc. of 
 the extract in a Babcock milk bottle. Add 1 cc. dilute HC1 
 (1 to 1) and about 28 cc. of warm, water at 60 C. Mix 
 and allow the bottle to stand in warm water at the same 
 temperature for five minutes. Centrifuge for five minutes. 
 Add warm water to bring the oil into the graduated neck. 
 Centrifuge for two minutes more and stand the bottle in 
 water at 60 C. up to the top of the oil column for a few 
 minutes, and read the per cent of oil by volume. 
 
 If more than 2 per cent of oil is present, add 0.4 per 
 cent to correct for the oil retained in solution. If between 
 1 and 2 per cent, add 0.3 per cent for correction. 
 
66 
 
 ELEMENTARY APPLIED CHEMISTEY 
 
 TABLE FOR DETERMINATION OF ALCOHOL PER- 
 CENTAGES ! 
 
 BY SQUIBB, DRINKWATER, AND GILPIN 
 
 SPECIFIC 
 GRAVITY 
 
 AT f F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATfgF. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATfgoF. 
 
 ALCOHOL 
 
 Pel- 
 cent 
 by vol- 
 ume 
 
 Pel- 
 cent 
 by 
 
 weight 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 
 by 
 
 weight 
 
 1.00000 
 
 0.00 
 
 0.00 
 
 0.99775 
 
 1.50 
 
 1.19 
 
 0.99557 
 
 3.00 
 
 2.39 
 
 0.99992 
 
 0.05 
 
 0.04 
 
 .99768 
 
 1.55 
 
 1.23 
 
 .99550 
 
 3.05 
 
 2.43 
 
 .99984 
 
 0.10 
 
 0.08 
 
 .99760 
 
 1.60 
 
 1.27 
 
 .99543 
 
 3.10 
 
 2.47 
 
 .99976 
 
 0.15 
 
 0.12 
 
 .99753 
 
 1.65 
 
 1.31 
 
 .99536 
 
 3.15 
 
 2.51 
 
 .99968 
 
 0.20 
 
 0.16 
 
 .99745 
 
 1.70 
 
 1.35 
 
 .99529 
 
 3.20 
 
 2.55 
 
 .99961 
 
 0.25 
 
 0.20 
 
 .99738 
 
 1.75 
 
 1.39 
 
 .99522 
 
 3.25 
 
 2.59 
 
 .99953 
 
 0.30 
 
 0.24 
 
 .99731 
 
 1.80 
 
 1.43 
 
 .99515 
 
 3.30 
 
 2.64 
 
 .99945 
 
 0.35 
 
 0.28 
 
 .99723 
 
 1.85 
 
 1.47 
 
 .99508 
 
 3.35 
 
 2.68 
 
 .99937 
 
 0.40 
 
 0.32 
 
 .99716 
 
 1.90 
 
 1.51 
 
 .99501 
 
 3.40 
 
 2.72 
 
 .99930 
 
 0.45 
 
 0.36 
 
 .99708 
 
 1.95 
 
 1.55 
 
 .99494 
 
 3.45 
 
 2.76 
 
 .99923 
 
 0.50 
 
 0.40 
 
 .99701 
 
 2.00 
 
 1.59 
 
 .99487 
 
 3.50 
 
 2.80 
 
 .99915 
 
 0.55 
 
 0.44 
 
 .99694 
 
 2.05 
 
 1.63 
 
 .99480 
 
 3.55 
 
 2.84 
 
 .99907 
 
 0.60 
 
 0.48 
 
 .99687 
 
 2.10 
 
 1.67 
 
 .99473 
 
 3.60 
 
 2.88 
 
 .99900 
 
 0.65 
 
 0.52 
 
 .99679 
 
 2.15 
 
 1.71 
 
 .99466 
 
 3.65 
 
 2.92 
 
 .99892 
 
 0.70 
 
 0.56 
 
 .99672 
 
 2.20 
 
 1.75 
 
 .99459 
 
 3.70 
 
 2.96 
 
 .99884 
 
 0.75 
 
 0.60 
 
 .99665 
 
 2.25 
 
 1.79 
 
 .99452 
 
 3.75 
 
 3.00 
 
 .99877 
 
 0.80 
 
 0.64 
 
 .99658 
 
 2.30 
 
 1.83 
 
 .99445 
 
 3.80 
 
 3.04 
 
 .99869 
 
 0.85 
 
 0.67 
 
 .99651 
 
 2.35 
 
 1.87 
 
 .99438 
 
 3.85 
 
 3.08 
 
 .99861 
 
 0.90 
 
 0.71 
 
 .99643 
 
 2.40 
 
 1.91 
 
 .99431 
 
 3.90 
 
 3.12 
 
 .99854 
 
 0.95 
 
 0.75 
 
 .99636 
 
 2.45 
 
 1.95 
 
 .99424 
 
 3.95 
 
 3.16 
 
 .99849 
 
 .00 
 
 0.79 
 
 .99629 
 
 2.50 
 
 1.99 
 
 .99417 
 
 4.00 
 
 3.20 
 
 .99842 
 
 .05 
 
 0.83 
 
 .99622 
 
 2.55 
 
 2.03 
 
 .99410 
 
 4.05 
 
 3.24 
 
 .99834 
 
 .10 
 
 0.87 
 
 .99615 
 
 2.60 
 
 2.07 
 
 .99403 
 
 4.10 
 
 3.28 
 
 .99827 
 
 .15 
 
 0.91 
 
 .99607 
 
 2.65 
 
 2.11 
 
 .99397 
 
 4.15 
 
 3.32 
 
 .99819 
 
 .20 
 
 0.95 
 
 .93600 
 
 2.70 
 
 2.15 
 
 .99390 
 
 4.20 
 
 3.36 
 
 .99812 
 
 .25 
 
 0.99 
 
 .99593 
 
 2.75 
 
 2.19 
 
 .99383 
 
 4.25 
 
 3.40 
 
 .99805 
 
 .30 
 
 1.03 
 
 .99586 
 
 2.80 
 
 2.23 
 
 .99376 
 
 4.30 
 
 3.44 
 
 .99797 
 
 .35 
 
 1.07 
 
 .99579 
 
 2.85 
 
 2.27 
 
 .99369 
 
 4.35 
 
 3.48 
 
 .99790 
 
 .40 
 
 1.11 
 
 .99571 
 
 2.90 
 
 2.31 
 
 .99363 
 
 4.40 
 
 3.52 
 
 .99782 
 
 .45 
 
 1.15 
 
 .99564 
 
 2.95 
 
 2.35 
 
 .99356 
 
 4.45 
 
 3.56 
 
 1 From Bulletin No. 107, United States Department of Agriculture. 
 
PERCENTAGE OF ALCOHOL 
 
 67 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 ATggF. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT f go F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATfgOF. 
 
 ALCOHOL 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 
 by 
 weight 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 
 by 
 
 weight 
 
 0.99349 
 
 4.50 
 
 3.60 
 
 0.99117 
 
 6.25 
 
 5.00 
 
 0.98897 
 
 8.00 
 
 6.42 
 
 .99342 
 
 4.55 
 
 3.64 
 
 .99111 
 
 6.30 
 
 5.05 
 
 .98891 
 
 8.05 
 
 6.46 
 
 .99335 
 
 4.60 
 
 3.68 
 
 .99104 
 
 6.35 
 
 5.09 
 
 .98885 
 
 8.10 
 
 6.50 
 
 .99329 
 
 4.65 
 
 3.72 
 
 .99098 
 
 6.40 
 
 5.13 
 
 .98879 
 
 8.15 
 
 6.54 
 
 .99322 
 
 4.70 
 
 3.76 
 
 .99091 
 
 6.45 
 
 5.17 
 
 .98873 
 
 8.20 
 
 6.58 
 
 .99315 
 
 4.75 
 
 3.80 
 
 .99085 
 
 6.50 
 
 5.21 
 
 .98867 
 
 8.25 
 
 6.62 
 
 .99308 
 
 4.80 
 
 3.84 
 
 .99079 
 
 6.55 
 
 5.25 
 
 .98861 
 
 8.30 
 
 6.67 
 
 .99301 
 
 4.85 
 
 3.88 
 
 .99072 
 
 6.60 
 
 5.29 
 
 .98855 
 
 8.35 
 
 6.71 
 
 .99295 
 
 4.90 
 
 3.92 
 
 .99066 
 
 6.65 
 
 5.33 
 
 .98849 
 
 8.40 
 
 6.75 
 
 .99288 
 
 4.95 
 
 3.96 
 
 .99059 
 
 6.70 
 
 5.37 
 
 .98843 
 
 8.45 
 
 6.79 
 
 .99281 
 
 5.00 
 
 4.00 
 
 .99053 
 
 6.75 
 
 5.41 
 
 .98837 
 
 8.50 
 
 6.83 
 
 .99274 
 
 5.05 
 
 4.04 
 
 .99047 
 
 6.80 
 
 5.45 
 
 .98831 
 
 8.55 
 
 6.87 
 
 .992(38 
 
 5.10 
 
 4.08 
 
 .99040 
 
 6.85 
 
 5.49 
 
 .98825 
 
 8.60 
 
 6.91 
 
 .99261 
 
 5.15 
 
 4.12 
 
 .99034 
 
 6.90 
 
 5.53 
 
 .98819 
 
 8.65 
 
 6.95 
 
 .99255 
 
 5.20 
 
 4.16 
 
 .99027 
 
 6.95 
 
 5.57 
 
 .98813 
 
 8.70 
 
 6.99 
 
 .99248 
 
 5.25 
 
 4.20 
 
 .99021 
 
 7.00 
 
 5.61 
 
 .98807 
 
 8.75 
 
 7.03 
 
 .99241 
 
 5.30 
 
 4.24 
 
 .99015 
 
 7.05 
 
 5.65 
 
 .98801 
 
 8.80 
 
 7.07 
 
 .99235 
 
 5.35 
 
 4.28 
 
 .99009 
 
 7.10 
 
 5.69 
 
 .98795 
 
 8.85 
 
 7.11 
 
 .99228 
 
 5.40 
 
 4.32 
 
 .99002 
 
 7.15 
 
 5.73 
 
 .98789 
 
 8.90 
 
 7.15 
 
 .99222 
 
 5.45 
 
 4.36 
 
 .98996 
 
 7.20 
 
 5.77 
 
 .98783 
 
 8.95 
 
 7.19 
 
 .99215 
 
 5.50 
 
 4.40 
 
 .98990 
 
 7.25 
 
 5.81 
 
 .98777 
 
 9.00 
 
 7.23 
 
 .99208 
 
 5.55 
 
 4.44 
 
 .98984 
 
 7.30 
 
 5.86 
 
 .98771 
 
 9.05 
 
 7.27 
 
 .99202 
 
 5.60 
 
 4.48 
 
 .98978 
 
 7.35 
 
 5.90 
 
 .98765 
 
 9.10 
 
 7.31 
 
 .99195 
 
 5.65 
 
 4.52 
 
 .98971 
 
 7.40 
 
 5.94 
 
 .98759 
 
 9.15 
 
 7.35 
 
 .99189 
 
 5.70 
 
 4.56 
 
 .98965 
 
 7.45 
 
 5.98 
 
 .98754 
 
 9.20 
 
 7.39 
 
 .99182 
 
 5.75 
 
 4.60 
 
 .98959 
 
 7.50 
 
 6.02 
 
 .98748 
 
 9.25 
 
 7.43 
 
 .99175 
 
 5.80 
 
 4.64 
 
 .98953 
 
 7.55 
 
 6.06 
 
 .98742 
 
 9.30 
 
 7.48 
 
 .99169 
 
 5.85 
 
 4.68 
 
 .98947 
 
 7.60 
 
 6.10 
 
 .98736 
 
 9.35 
 
 7.52 
 
 .99162 
 
 5.90 
 
 4.72 
 
 .98940 
 
 7.65 
 
 6.14 
 
 .98730 
 
 9.40 
 
 7.56 
 
 .99156 
 
 5.95 
 
 4.76 
 
 .98934 
 
 7.70 
 
 6.18 
 
 .98724 
 
 9.45 
 
 7.60 
 
 .99149 
 
 6.00 
 
 4.80 
 
 .98928 
 
 7.75 
 
 6.22 
 
 .98719 
 
 9.50 
 
 7.64 
 
 .99143 
 
 6.05 
 
 4.84 
 
 .98922 
 
 7.80 
 
 6.26 
 
 .98713 
 
 9.55 
 
 7.68 
 
 .99136 
 
 6.10 
 
 4.88 
 
 .98916 
 
 7.85 
 
 6.30 
 
 .98707 
 
 9.60 
 
 7.72 
 
 .99130 
 
 6.15 
 
 4.92 
 
 .98909 
 
 7.90 
 
 6.34 
 
 .98701 
 
 9.65 
 
 7.76 
 
 .99123 
 
 6.20 
 
 4.96 
 
 .98903 
 
 7.95 
 
 6.38 
 
 .98695 
 
 9.70 
 
 7.80 
 
68 ELEMENTAKY APPLIED CHEMISTRY 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT ggo F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 AT gg F. 
 
 AXCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT g0 F. 
 
 ALCOHOL 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Pel- 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 by 
 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 
 by 
 weight 
 
 0.98689 
 
 9.75 
 
 7.84 
 
 0.98491 
 
 11.50 
 
 9.27 
 
 0.98299 
 
 13.25 
 
 10.69 
 
 .98683 
 
 9.80 
 
 7.88 
 
 .98485 
 
 11.55 
 
 9.31 
 
 .98294 
 
 13.30 
 
 10.74 
 
 .98678 
 
 9.85 
 
 7.92 
 
 .98479 
 
 11.60 
 
 9.35 
 
 .98289 
 
 13.35 
 
 10.78 
 
 .98672 
 
 9.90 
 
 7.96 
 
 .98474 
 
 11.65 
 
 9.39 
 
 .98283 
 
 13.40 
 
 10.82 
 
 .98666 
 
 9.95 
 
 8.00 
 
 .98468 
 
 11.70 
 
 9.43 
 
 .98278 
 
 13.45 
 
 10.86 
 
 .98660 
 
 10.00 
 
 8.04 
 
 .98463 
 
 11.75 
 
 9.47 
 
 .98273 
 
 13.50 
 
 10.90 
 
 .98654 
 
 10.05 
 
 8.08 
 
 .98457 
 
 11.80 
 
 9.51 
 
 .98267 
 
 13.55 
 
 10.94 
 
 .98649 
 
 10.10 
 
 8.12 
 
 .98452 
 
 11.85 
 
 9.55 
 
 .98262 
 
 13.60 
 
 10.98 
 
 .98643 
 
 10.15 
 
 8.16 
 
 .98446 
 
 11.90 
 
 9.59 
 
 .98256 
 
 13.65 
 
 11.02 
 
 .98637 
 
 10.20 
 
 8.20 
 
 .98441 
 
 11.95 
 
 9.63 
 
 .98251 
 
 13.70 
 
 11.06 
 
 .98632 
 
 10.25 
 
 8.24 
 
 .98435 
 
 12.00 
 
 9.67 
 
 .98246 
 
 13.75 
 
 11.11 
 
 .98626 
 
 10.30 
 
 8.29 
 
 .98430 
 
 12.05 
 
 9.71 
 
 .98240 
 
 13.80 
 
 11.15 
 
 .98620 
 
 10.35 
 
 8.33 
 
 .98424 
 
 12.10 
 
 9.75 
 
 .98235 
 
 13.85 
 
 11.19 
 
 .98614 
 
 10.40 
 
 8.37 
 
 .98419 
 
 12.15 
 
 9.79 
 
 .98230 
 
 13.90 
 
 11.23 
 
 .98609 
 
 10.45 
 
 8.41 
 
 .98413 
 
 12.20 
 
 9.83 
 
 .98224 
 
 13.95 
 
 11.27 
 
 .98603 
 
 10.50 
 
 8.45 
 
 .98408 
 
 12.25 
 
 9.87 
 
 .98219 
 
 14.00 
 
 11.31 
 
 .98597 
 
 10.55 
 
 8.49 
 
 .98402 
 
 12.30 
 
 9.92 
 
 .98214 
 
 14.05 
 
 11.35 
 
 .98592 
 
 10.60 
 
 8.53 
 
 .98397 
 
 12.35 
 
 9.96 
 
 .98209 
 
 14.10 
 
 11.39 
 
 .98586 
 
 10.65 
 
 8.57 
 
 .98391 
 
 12.40" 
 
 10.00 
 
 .98203 
 
 14.15 
 
 11.43 
 
 .98580 
 
 10.70 
 
 8.61 
 
 .98386 
 
 12.45 
 
 10.04 
 
 .98198 
 
 14.20 
 
 11.47 
 
 .98575 
 
 10.75 
 
 8.65 
 
 .98381 
 
 12.50 
 
 10.08 
 
 .98193 
 
 14.25 
 
 11.52 
 
 .98569 
 
 10.80 
 
 8.70 
 
 .98375 
 
 12.55 
 
 10.12 
 
 .98188 
 
 14.30 
 
 11.56 
 
 .98563 
 
 10.85 
 
 8.74 
 
 .98370 
 
 12.60 
 
 10.16 
 
 .98182 
 
 14.35 
 
 11.60 
 
 .98557 
 
 10.90 
 
 8.78 
 
 .98364 
 
 12.65 
 
 10.20 
 
 .98177 
 
 14.40 
 
 11.64 
 
 .98552 
 
 10.95 
 
 8.82 
 
 .98359 
 
 12.70 
 
 10.24 
 
 .98172 
 
 14.45 
 
 11.68 
 
 .98546 
 
 11.00 
 
 8.86 
 
 .98353 
 
 12.75 
 
 10.28 
 
 .98167 
 
 14.50 
 
 11.72 
 
 .98540 
 
 11.05 
 
 8.90 
 
 .98348 
 
 12.80 
 
 10.33 
 
 .98161 
 
 14.55 
 
 11.76 
 
 .98535 
 
 11.10 
 
 8.94 
 
 .98342 
 
 12.85 
 
 10.37 
 
 .98156 
 
 14.60 
 
 11.80 
 
 .98529 
 
 11.15 
 
 8.98 
 
 .98337 
 
 12.90 
 
 10.41 
 
 .98151 
 
 14.65 
 
 11.84 
 
 .98524 
 
 11.20 
 
 9.02 
 
 .98331 
 
 12.95 
 
 10.45 
 
 .98146 
 
 14.70 
 
 11.88 
 
 .98518 
 
 11.25 
 
 9.07 
 
 .98326 
 
 13.00 
 
 10.49 
 
 .98140 
 
 14.75 
 
 11.93 
 
 .98513 
 
 11.30 
 
 9.11 
 
 .98321 
 
 13.05 
 
 10.53 
 
 .98135 
 
 14.80 
 
 11.97 
 
 .98507 
 
 11.35 
 
 9.15 
 
 .98315 
 
 13.10 
 
 10.57 
 
 .98130 
 
 14.85 
 
 12.01 
 
 .98502 
 
 11.40 
 
 9.19 
 
 .98310 
 
 13.15 
 
 10.61 
 
 .98125 
 
 14.90 
 
 12.05 
 
 .98496 
 
 11.45 
 
 9.23 
 
 .98305 
 
 13.20 
 
 10.65 
 
 .98119 
 
 14.95 
 
 12.09 
 
PERCENTAGE OF ALCOHOL 
 
 69 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT|F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATggOF. 
 
 ALCOHOL 
 
 SPECIFIC 
 ORAVITY 
 
 AT|gF. 
 
 ALCOHOL 
 
 Pei- 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 weight 
 
 0.98114 
 
 15.00 
 
 12.13 
 
 0.97935 
 
 16.75 
 
 13.57 
 
 0.97758 
 
 18.50 
 
 15.02 
 
 .98108 
 
 15.05 
 
 12.17 
 
 .97929 
 
 16.80 
 
 13.62 
 
 .97753 
 
 18.55 
 
 15.06 
 
 .98104 
 
 15.10 
 
 12.21 
 
 .97924 
 
 16.85 
 
 13.66 
 
 .97748 
 
 18.60 
 
 15.10 
 
 .98099 
 
 15.15 
 
 12.25 
 
 .97919 
 
 16.90 
 
 13.70 
 
 .97743 
 
 18.65 
 
 15.14 
 
 .98093 
 
 15.20 
 
 12.29 
 
 .97914 
 
 16.95 
 
 13.74 
 
 .97738 
 
 IB. 70 
 
 15.18 
 
 .98088 
 
 15.25 
 
 12.33 
 
 .97909 
 
 17.00 
 
 13.78 
 
 .97733 
 
 18.75 
 
 15.22 
 
 .98083 
 
 15.30 
 
 12.38 
 
 .97904 
 
 17.05 
 
 13.82 
 
 .97728 
 
 18.80 
 
 15.27 
 
 .98078 
 
 15.35 
 
 12.42 
 
 .97899 
 
 17.10 
 
 13.86 
 
 .97723 
 
 18.85 
 
 15.31 
 
 .98073 
 
 15.40 
 
 12.46 
 
 .97894 
 
 17.15 
 
 13.90 
 
 .97718 
 
 18.90 
 
 15.38 
 
 .98008 
 
 15.45 
 
 12.50 
 
 .97889 
 
 17.20 
 
 13.94 
 
 .97713 
 
 18.95 
 
 15.39 
 
 ..98063 
 
 15.50 
 
 12.54 
 
 .97884 
 
 17.25 
 
 13.98 
 
 .97708 
 
 19.00 
 
 15.43 
 
 .98057 
 
 15.55 
 
 12.58 
 
 .97879 
 
 17.30 
 
 14.03 
 
 .97703 
 
 19.05 
 
 15.47 
 
 .98052 
 
 15.60 
 
 12.62 
 
 ..97874 
 
 17.35 
 
 14.07 
 
 .97698 
 
 19.10 
 
 15.51 
 
 .98047 
 
 15.65 
 
 12.66 
 
 .97869 
 
 17.40 
 
 14.11 
 
 .97693 
 
 19.15 
 
 15.55 
 
 .98042 
 
 15.70 
 
 12.70 
 
 .97864 
 
 17.45 
 
 14.15 
 
 .97688 
 
 19.20 
 
 15.59 
 
 .98037 
 
 15.75 
 
 12.75 
 
 .97859 
 
 17.50 
 
 14.19 
 
 .97683 
 
 19.25 
 
 15.63 
 
 .98032 
 
 15.80 
 
 12.79 
 
 .97853 
 
 17". 55 
 
 14.23 
 
 .97678 
 
 19.30 
 
 15.68 
 
 .98026 
 
 15.85 
 
 12.83 
 
 .97848 
 
 17.60 
 
 14.27 
 
 .97673 
 
 19.35 
 
 15.72 
 
 .98021 
 
 15.90 
 
 12.87 
 
 .97843 
 
 17.65 
 
 14.31 
 
 .97668 
 
 19.40 
 
 15.76 
 
 .98016 
 
 15.95 
 
 12.91 
 
 .97838 
 
 17.70 
 
 14.35 
 
 .97663 
 
 19.45 
 
 15.80 
 
 .98011 
 
 16.00 
 
 12.95 
 
 .97.833 
 
 17.75 
 
 14.40 
 
 .97658 
 
 19.50 
 
 15.84 
 
 .98005 
 
 16.05 
 
 12.99 
 
 .97828 
 
 17.80 
 
 14.44 
 
 .97653 
 
 19.55 
 
 15.88 
 
 .98001 
 
 16.10 
 
 13.03 
 
 .97823 
 
 17.85 
 
 14.48 
 
 .97648 
 
 19.60 
 
 15.93 
 
 .9799(5 
 
 16.15 
 
 13.08 
 
 .97818 
 
 17.90 
 
 14.52 
 
 .97643 
 
 19.65 
 
 15.97 
 
 .97991 
 
 16.20 
 
 13.12 
 
 .97813 
 
 17.95 
 
 14.56 
 
 .97638 
 
 19.70 
 
 16.01 
 
 .97986 
 
 16.25 
 
 13.16 
 
 .97808 
 
 18.00 
 
 14.60 
 
 .97633 
 
 19.75 
 
 16.05 
 
 .97980 
 
 16.30 
 
 13.20 
 
 .97803 
 
 18.05 
 
 14.64 
 
 .97628 
 
 19.80 
 
 16.09 
 
 .97975 
 
 16.35 
 
 13.24 
 
 .97798 
 
 18.10 
 
 14.68 
 
 .97623 
 
 19.85 
 
 16.14 
 
 .97970 
 
 16.40 
 
 13.29 
 
 .97793 
 
 18.15 
 
 14.73 
 
 .97618 
 
 19.90 
 
 16.18 
 
 .97965 
 
 16.45 
 
 13.33 
 
 .97788 
 
 18.20 
 
 14.77 
 
 .97613 
 
 19.95 
 
 16.22 
 
 .97960 
 
 16.50 
 
 13.37 
 
 .97783 
 
 18.25 
 
 14.81 
 
 .97608 
 
 20.00 
 
 16.26 
 
 .97955 
 
 16.55 
 
 13.41 
 
 .97778 
 
 18.30 
 
 14.85 
 
 .97603 
 
 20.05 
 
 16.30 
 
 .97950 
 
 16.60 
 
 13.45 
 
 .97773 
 
 18.35 
 
 14.89 
 
 .97598 
 
 20.10 
 
 16.34 
 
 .97945 
 
 16.65 
 
 13.49 
 
 .97768 
 
 18.40 
 
 14.94 
 
 .97593 
 
 20.15 
 
 16.38 
 
 .97940 
 
 16.70 
 
 13.53 
 
 .97763 
 
 18.45 
 
 14.98 
 
 .97588 
 
 20.20 
 
 16.42 
 
70 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT igop. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT f F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATfgOF. 
 
 ALCOHOL 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 weigh i 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 weight 
 
 0.97583 
 
 20.25 
 
 16.46 
 
 0.97406 
 
 22.00 
 
 17.92 
 
 0.97227 
 
 23.75 
 
 19.38 
 
 .97578 
 
 20.30 
 
 16.51 
 
 .97401 
 
 22.05 
 
 17.96 
 
 .97222 
 
 23.80 
 
 19.42 
 
 .97573 
 
 20.35 
 
 16.58 
 
 .97396 
 
 22.10 
 
 18.00 
 
 .97216 
 
 23.85 
 
 19.46 
 
 .97568 
 
 20.40 
 
 16.59 
 
 .97391 
 
 22.15 
 
 18.05 
 
 .97211 
 
 23.90 
 
 19.51 
 
 .97563 
 
 20.45 
 
 16.63 
 
 .97386 
 
 22.20 
 
 18.09 
 
 .97206 
 
 23.95 
 
 19.55 
 
 .97558 
 
 20.50 
 
 16.67 
 
 .97381 
 
 22.25 
 
 18.13 
 
 .97201 
 
 24.00 
 
 19.59 
 
 .97552 
 
 20.55 
 
 16.71 
 
 .97375 
 
 22.30 
 
 18.17 
 
 .97196 
 
 24.05 
 
 19.63 
 
 .97547 
 
 20.60 
 
 16.75 
 
 .97370 
 
 22.35 
 
 18.21 
 
 .97191 
 
 24.10 
 
 19.67 
 
 .97542 
 
 20.65 
 
 16.80 
 
 .97365 
 
 22.40 
 
 18.26 
 
 .97185 
 
 24.15 
 
 19.72 
 
 .97537 
 
 20.70 
 
 16.84 
 
 .97360 
 
 22.45 
 
 18.30 
 
 .97180 
 
 24.20 
 
 19.76 
 
 .97532 
 
 20.75 
 
 16.88 
 
 .97355 
 
 22.50 
 
 18.34 
 
 .97175 
 
 24.25 
 
 19.80 
 
 .97527 
 
 20.80 
 
 16.92 
 
 .97350 
 
 22.55 
 
 18.38 
 
 .97170 
 
 24.30 
 
 19.84 
 
 .97522 
 
 20.85 
 
 16.96 
 
 .97345 
 
 22.60 
 
 18.42 
 
 .97165 
 
 24.35 
 
 19.88 
 
 .97517 
 
 20.90 
 
 17.01 
 
 .97340 
 
 22.65 
 
 18.47 
 
 .97159 
 
 24.40 
 
 19.93 
 
 .97512 
 
 20.95 
 
 17.05 
 
 .97335 
 
 22.70 
 
 18.51 
 
 .97154 
 
 24.45 
 
 19.97 
 
 .97507 
 
 21.00 
 
 17.09 
 
 .97330 
 
 22.75 
 
 18.55 
 
 .97149 
 
 24.50 
 
 20.01 
 
 .97502 
 
 21.05 
 
 17.13 
 
 .97324 
 
 22.80 
 
 18.59 
 
 .97144 
 
 24.55 
 
 20.05 
 
 .97497 
 
 21.10 
 
 17.17 
 
 .97319 
 
 22.85 
 
 18.63 
 
 .97139 
 
 24.60 
 
 20.09 
 
 .97492 
 
 21.15 
 
 17.22 
 
 .97314 
 
 22.90 
 
 18.68 
 
 .97133 
 
 24.65 
 
 20.14 
 
 .97487 
 
 21.20 
 
 17.26 
 
 .97309 
 
 22.95 
 
 18.72 
 
 ' .97128 
 
 24.70 
 
 20.18 
 
 .97482 
 
 21.25 
 
 17.30 
 
 .97304 
 
 23.00 
 
 18.76 
 
 .97123 
 
 24.75 
 
 20.22 
 
 .97477 
 
 21.30 
 
 17.34 
 
 .97299 
 
 23.05 
 
 18.80 
 
 .97118 
 
 24.80 
 
 20.26 
 
 .97472 
 
 21.35 
 
 17.38 
 
 .97294 
 
 23.10 
 
 18.84 
 
 .97113 
 
 24.85 
 
 20.30 
 
 .97467 
 
 21.40 
 
 17.43 
 
 .97289 
 
 23.15 
 
 18.88 
 
 .97107 
 
 24.90 
 
 20.35 
 
 .97462 
 
 21.45 
 
 17.47 
 
 .97283 
 
 23.20 
 
 18.92 
 
 .97102 
 
 24.95 
 
 20.39 
 
 .97457 
 
 21.50 
 
 17.51 
 
 .97278 
 
 23.25 
 
 18.96 
 
 .97097 
 
 25.00 
 
 20.43 
 
 .97451 
 
 21.55 
 
 17.55 
 
 .97273 
 
 23.30 
 
 19.01 
 
 .97092 
 
 25.05 
 
 20.47 
 
 .97446 
 
 21.60 
 
 17.59 
 
 .97268 
 
 23.35 
 
 19.05 
 
 .97086 
 
 25.10 
 
 20.51 
 
 .97441 
 
 21.65 
 
 17.63 
 
 .97263 
 
 23.40 
 
 19.09 
 
 .97081 
 
 25.15 
 
 20.56 
 
 .97436 
 
 21.70 
 
 17.67 
 
 .97258 
 
 23.45 
 
 19.13 
 
 .97076 
 
 25.20 
 
 20.60 
 
 .97431 
 
 21.75 
 
 17.71 
 
 .97253 
 
 23.50 
 
 19.17 
 
 .97071 
 
 25.25 
 
 20.64 
 
 .97426 
 
 21.80 
 
 17.76 
 
 .97247 
 
 23.55 
 
 19.21 
 
 .97065 
 
 25.30 
 
 20.68 
 
 .97421 
 
 21.85 
 
 17.80 
 
 .97242 
 
 23.60 
 
 19.25 
 
 .97060 
 
 25.35 
 
 20.72 
 
 .97416 
 
 21.90 
 
 17.84 
 
 .97237 
 
 23.65 
 
 19.30 
 
 .97055 
 
 25.40 
 
 20.77 
 
 .97411 
 
 21.95 
 
 17.88 
 
 .97232 
 
 23.70 
 
 19.34 
 
 .97049 
 
 25.45 
 
 20.81 
 
PEKCENTAGE OF ALCOHOL 
 
 71 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT8F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 ATggF. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT|SF. 
 
 ALCOHOL 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 
 by 
 
 weight 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 
 weight 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 
 by 
 
 weight 
 
 0.97044 
 
 25.50 
 
 20.85 
 
 0.96855 
 
 27.25 
 
 22.33 
 
 0.96658 
 
 29.00 
 
 23.81 
 
 .97039 
 
 25.55 
 
 20.89 
 
 .96850 
 
 27.30 
 
 22.37 
 
 .96652 
 
 29.05 
 
 23.85 
 
 .97033 
 
 25.60 
 
 20.93 
 
 .96844 
 
 27.35 
 
 22.41 
 
 .96646 
 
 29.10 
 
 23.89 
 
 .97028 
 
 25.65 
 
 20.98 
 
 .96839 
 
 27.40 
 
 22.45 
 
 .96640 
 
 29.15 
 
 23.94 
 
 .97023 
 
 25.70 
 
 21.02 
 
 .96833 
 
 27.45 
 
 22.50 
 
 .96635 
 
 29.20 
 
 23.98 
 
 .97018 
 
 25.75 
 
 21.06 
 
 .96828 
 
 27.50 
 
 22.54 
 
 .96629 
 
 29.25 
 
 24.02 
 
 .97012 
 
 25.80 
 
 21.10 
 
 .96822 
 
 27.55 
 
 22.58 
 
 .96623 
 
 29.30 
 
 24.06 
 
 .97007 
 
 25.85 
 
 21.14 
 
 .96816 
 
 27.60 
 
 22.62 
 
 .96617 
 
 29.35 
 
 24.10 
 
 .97001 
 
 25.90 
 
 21.19 
 
 .96811 
 
 27.65 
 
 22.67 
 
 .96611 
 
 29.40 
 
 24.15 
 
 .96996 
 
 25.95 
 
 21.23 
 
 .96805 
 
 27.70 
 
 22.71 
 
 .96605 
 
 29.45 
 
 24.19 
 
 .96991 
 
 26.00 
 
 21.27 
 
 .96800 
 
 27.75 
 
 22.75 
 
 .96600 
 
 29.50 
 
 24.23 
 
 .96986 
 
 26.05 
 
 21.31 
 
 .96794 
 
 27.80 
 
 22.79 
 
 .96594 
 
 29.55 
 
 24.27 
 
 .96980 
 
 26.10 
 
 21.35 
 
 .96789 
 
 27.85 
 
 22.83 
 
 .96587 
 
 29.60 
 
 24.32 
 
 .96975 
 
 26.15 
 
 21.40 
 
 .96783 
 
 27.90 
 
 22.88 
 
 .96582 
 
 29.65 
 
 24.36 
 
 .96969 
 
 20.20 
 
 21.44 
 
 .96778 
 
 27.95 
 
 22.92 
 
 .96576 
 
 29.70 
 
 24.40 
 
 .96964 
 
 26.25 
 
 21.48 
 
 .96772 
 
 28.00 
 
 22.96 
 
 .96570 
 
 29.75 
 
 24.45 
 
 .90959 
 
 26.30 
 
 21.52 
 
 .96766 
 
 28.05 
 
 23.00 
 
 .96564 
 
 29.80 
 
 24.49 
 
 .96953 
 
 26.35 
 
 21.56 
 
 .96761 
 
 28.10 
 
 23.04 
 
 .96559 
 
 29.85 
 
 24.53 
 
 .96949 
 
 26.40 
 
 21.61 
 
 .96755 
 
 28.15 
 
 23.09 
 
 .96553 
 
 29.90 
 
 24.57 
 
 .901)42 
 
 26.45 
 
 21.65 
 
 .96749 
 
 28.20 
 
 23.13 
 
 .96547 
 
 29.95 
 
 24.62 
 
 .96937 
 
 26.50 
 
 21.69 
 
 .96744 
 
 28.25 
 
 23.17 
 
 .96541 
 
 30.00 
 
 24.66 
 
 .96932 
 
 26.55 
 
 21.73 
 
 .96738 
 
 28.30 
 
 23.21 
 
 .96535 
 
 30.05 
 
 24.70 
 
 .96926 
 
 26.60 
 
 21.77 
 
 .96732 
 
 28.35 
 
 23.25 
 
 .96529 
 
 30.10 
 
 24.74 
 
 .96921 
 
 26.65 
 
 21.82 
 
 .96726 
 
 28.40 
 
 23.30 
 
 .96523 
 
 30.15 
 
 24.79 
 
 .96915 
 
 26.70 
 
 21.86 
 
 .96721 
 
 28.45 
 
 23.34 
 
 .96517 
 
 30.20 
 
 24.83 
 
 .96910 
 
 26.75 
 
 21.90 
 
 .96715 
 
 28.50 
 
 23.38 
 
 .96511 
 
 30.25 
 
 24.87 
 
 .96906 
 
 26.80 
 
 21.94 
 
 .96709 
 
 28.55 
 
 23.42 
 
 .96505 
 
 30.30 
 
 24.91 
 
 .96899 
 
 26.85 
 
 21.98 
 
 .96704 
 
 28.60 
 
 23.47 
 
 .96499 
 
 30.35 
 
 24.95 
 
 .96894 
 
 26.90 
 
 22.03 
 
 .96698 
 
 28.65 
 
 23.51 
 
 .96493 
 
 30.40 
 
 25.00 
 
 .96888 
 
 26.95 
 
 22.07 
 
 .96692 
 
 28.70 
 
 23.55 
 
 .96487 
 
 30.45 
 
 25.04 
 
 .96883 
 
 27.00 
 
 22.11 
 
 .96687 
 
 28.75 
 
 23.60 
 
 .96481 
 
 30.50 
 
 25.08 
 
 .96877 
 
 27.05 
 
 22.15 
 
 .96681 
 
 28.80 
 
 23.64 
 
 .96475 
 
 30.55 
 
 25.12 
 
 .96872 
 
 27.10 
 
 22.20 
 
 .96675 
 
 28.85 
 
 23.68 
 
 .96469 
 
 30.60 
 
 25.17 
 
 ,96866 
 
 27.15 
 
 22.24 
 
 .96669 
 
 28.90 
 
 23.72 
 
 .96463 
 
 30.65 
 
 25.21 
 
 .96861 
 
 27.20 
 
 22.28 
 
 .96664 
 
 28.95 
 
 23.77 
 
 .96457 
 
 30.70 
 
 25.25 
 
72 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT |g F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT |0 F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 ATgF. 
 
 ALCOHOL 
 
 Per 
 
 cent 
 by. vol- 
 ume 
 
 Per 
 cent 
 by 
 
 weigh 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 
 i>y 
 
 weight 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 bj 
 
 weight 
 
 0.96451 
 
 30.75 
 
 25.30 
 
 0.96235 
 
 32.50 
 
 26.80 
 
 0.96010 
 
 34.25 
 
 28.31 
 
 .90445 
 
 30.80 
 
 25.34 
 
 .96229 
 
 32.55 
 
 26.84 
 
 .96003 
 
 34.30 
 
 28.35 
 
 .96439 
 
 30.85 
 
 25.38 
 
 .96222 
 
 32.60 
 
 26.89 
 
 .95996 
 
 34.35 
 
 28.39 
 
 .96433 
 
 30.90 
 
 25.42 
 
 .96216 
 
 32.65 
 
 26.93 
 
 .96990 
 
 34.40 
 
 28.43 
 
 .96427 
 
 30.95 
 
 25.47 
 
 .96210 
 
 32.70 
 
 26.97 
 
 .95983 
 
 34.45 
 
 28.48 
 
 .96421 
 
 31.00 
 
 25.51 
 
 .96204 
 
 32.75 
 
 27.02 
 
 .95977 
 
 34.50 
 
 28.52 
 
 .96415 
 
 31.05 
 
 25.55 
 
 .96197 
 
 32.80 
 
 27.06 
 
 .95970 
 
 34.55 
 
 28.56 
 
 .96409 
 
 31.10 
 
 25.60 
 
 .96191 
 
 32.85 
 
 27.10 
 
 .95963 
 
 34.60 
 
 28.61 
 
 .96403 
 
 31.15 
 
 25.64 
 
 .96185 
 
 32.90 
 
 27.14 
 
 .95957 
 
 34.65 
 
 28.05 
 
 .96396 
 
 31.20 
 
 25.68 
 
 .96178 
 
 32.95 
 
 27.19 
 
 .95950 
 
 34.70 
 
 28.70 
 
 .96390 
 
 31.25 
 
 25.73 
 
 .96172 
 
 33.00 
 
 27.23 
 
 .95943 
 
 34.75 
 
 28.74 
 
 .96384 
 
 31.30 
 
 25.77 
 
 .96166 
 
 33.05 
 
 27.27 
 
 .95937 
 
 34.80 
 
 28.78 
 
 .96378 
 
 31.35 
 
 25.81 
 
 .96159 
 
 33.10 
 
 27.32 
 
 .95930 
 
 34.85 
 
 28.83 
 
 .96372 
 
 31.40 
 
 25.85 
 
 .96153 
 
 33.15 
 
 27.36 
 
 .95923 
 
 34.90 
 
 28.87 
 
 .96366 
 
 31.45 
 
 25.90 
 
 .96146 
 
 33.20 
 
 27.40 
 
 .95917 
 
 34.95 
 
 28.92 
 
 .96360 
 
 31.50 
 
 25.94 
 
 .96140 
 
 33.25 
 
 27.45 
 
 .95910 
 
 '35.00 
 
 28.96 
 
 .96353 
 
 31.55 
 
 25.98' 
 
 .96133 
 
 33.30 
 
 27.49 
 
 .95903 
 
 35.05 
 
 29.00 
 
 .96347 
 
 31.60 
 
 26.03 
 
 .96127 
 
 33.35 
 
 27.53 
 
 .95896 
 
 35.10 
 
 29.05 
 
 .96341 
 
 31.65 
 
 26.07 
 
 -.96120 
 
 33.40 
 
 27.57 
 
 .95889 
 
 35.15 
 
 29.09 
 
 .96335 
 
 31.70 
 
 26.11 
 
 .96114 
 
 33.45 
 
 27.62 
 
 .95883 
 
 35.20 
 
 29.13 
 
 .96329 
 
 31.75 
 
 26.16 
 
 .96108 
 
 33.50 
 
 27.66 
 
 .95870 
 
 35.25 
 
 29.18 
 
 .96323 
 
 31.80 
 
 26.20 
 
 .96101 
 
 33.55 
 
 27.70 
 
 .95869 
 
 35.30 
 
 29.22 
 
 .96316 
 
 31.85 
 
 26.24 
 
 .96095 
 
 33.60 
 
 27.75 
 
 .958 
 
 35.35 
 
 29.26 
 
 .96310 
 
 31.90 
 
 26.28 
 
 .96088 
 
 33.65 
 
 27.79 
 
 .95855 
 
 35.40 
 
 29.30 
 
 .96304 
 
 31.95 
 
 26.33 
 
 .96082 
 
 33.70 
 
 27.83 
 
 .95848 
 
 35.45 
 
 29.35 
 
 .96298 
 
 32.00 
 
 26.37 
 
 .96075 
 
 33.75 
 
 27.88 
 
 .95842 
 
 35.50 
 
 29.30 
 
 .96292 
 
 32.05 
 
 26.41 
 
 .96069 
 
 33.80 
 
 27.92 
 
 .95835 
 
 35.55 
 
 29.43 
 
 .96285 
 
 32.10 
 
 26.46 
 
 .96062 
 
 33.85 
 
 27.96 
 
 .95828 
 
 35.60 
 
 29.48 
 
 .96279 
 
 32.15 
 
 26.50 
 
 .96056 
 
 33.90 
 
 28.00 
 
 .95821 
 
 35.65 
 
 29.52 
 
 .96273 
 
 32.20 
 
 26.54 
 
 .96049 
 
 33.95 
 
 28.05 
 
 .95814 
 
 35.70 
 
 29.57 
 
 .96267 
 
 32.25 
 
 26.59 
 
 .96043 
 
 34.00 
 
 28.09 
 
 .95807 
 
 35.75 
 
 29.61 
 
 .96260 
 
 32.30 
 
 26.63 
 
 .96036 
 
 34.05 
 
 28.13 
 
 .95800 
 
 35.80 
 
 29.65 
 
 .96254 
 
 32.35 
 
 26.67 
 
 .96030 
 
 34.10 
 
 28.18 
 
 .95794 
 
 35.85 
 
 29.70 
 
 .96248 
 
 32.40 
 
 26.71 
 
 .96023 
 
 34.15 
 
 28.22 
 
 .95787 
 
 35.90 
 
 29.74 
 
 .96241 
 
 32.45 
 
 26.76 
 
 .96016 
 
 34.20 
 
 28.26 
 
 .95780 
 
 35.95 
 
 29.79 
 
PERCENTAGE OF ALCOHOL 
 
 73 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GRAVITY 
 
 AT |g F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT |8 F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT8F. 
 
 ALCOHOL 
 
 Per 
 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 
 by 
 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 weight 
 
 0.95773 
 
 36.00 
 
 29.83 
 
 0.95523 
 
 37.75 
 
 31.36 
 
 0.95262 
 
 39.50 
 
 32.90 
 
 .95766 
 
 36.05 
 
 29.87 
 
 .95516 
 
 37.80 
 
 31.40 
 
 .95254 
 
 39.55 
 
 32.95 
 
 .95759 
 
 36.10 
 
 29.92 
 
 .95509 
 
 37.85 
 
 31.45 
 
 .95246 
 
 39.60 
 
 32.99 
 
 .95752 
 
 36.15 
 
 29.96 
 
 .95502 
 
 37.90 
 
 31.49 
 
 .95239 
 
 39.65 
 
 33.04 
 
 .95745 
 
 36.20 
 
 30.00 
 
 .95494 
 
 37.95 
 
 31.54 
 
 .95231 
 
 39.70 
 
 33.08 
 
 .95738 
 
 36.25 
 
 30.05 
 
 .95487 
 
 38.00 
 
 31.58 
 
 .95223 
 
 39.75 
 
 33.13 
 
 .95731 
 
 36.30 
 
 30.09 
 
 .95480 
 
 38.05 
 
 31.63 
 
 .95216 
 
 39.80 
 
 33.17 
 
 .95724 
 
 36.35 
 
 30.13 
 
 .95472 
 
 38.10 
 
 31.67 
 
 .95208 
 
 39.85 
 
 33.22 
 
 .95717 
 
 36.40 
 
 30.17 
 
 .95465 
 
 38.15 
 
 31.72 
 
 .95200 
 
 39.90 
 
 33.27 
 
 .95710 
 
 36.45 
 
 30.22 
 
 .95457 
 
 38.20 
 
 31.76 
 
 .95193 
 
 39.95 
 
 33.31 
 
 .95703 
 
 36.50 
 
 30.26 
 
 .95450 
 
 38.25 
 
 31.81 
 
 .95185 
 
 40.00 
 
 33.35 
 
 .95695 
 
 36.55 
 
 30.30 
 
 .95442 
 
 38.30 
 
 31.85 
 
 .95177 
 
 40.05 
 
 33.39 
 
 .95688 
 
 36.60 
 
 30.35 
 
 .95435 
 
 38.35 
 
 31.90 
 
 .95169 
 
 40.10 
 
 33.44 
 
 .95681 
 
 36.65 
 
 30.39 
 
 .95427 
 
 38.40 
 
 31.94 
 
 .95161 
 
 40.15 
 
 33.48 
 
 .95674 
 
 36.70 
 
 30.44 
 
 .95420 
 
 38.45 
 
 31.99 
 
 .95154 
 
 40.20 
 
 33.53 
 
 .95667 
 
 36.75 
 
 30.48 
 
 .95413 
 
 38.50 
 
 32.03 
 
 .95146 
 
 40.25 
 
 33.57 
 
 .95660 
 
 36.80 
 
 30.52 
 
 .95405 
 
 38.55 
 
 32.07 
 
 .95138 
 
 40.30 
 
 33.61 
 
 .95653 
 
 36.85 
 
 30.57 
 
 .95398 
 
 38.60 
 
 32.12 
 
 .95130 
 
 40.35 
 
 33.66 
 
 .95646 
 
 36.90 
 
 30.61 
 
 .95390 
 
 38.65 
 
 32.16 
 
 .95122 
 
 40.40 
 
 33.70 
 
 .95639 
 
 36.95 
 
 30.66 
 
 .95383 
 
 38.70 
 
 32.20 
 
 .95114 
 
 40.45 
 
 33.75 
 
 .95632 
 
 37.00 
 
 30.70 
 
 .95375 
 
 38.75 
 
 32.25 
 
 .95107 
 
 40.50 
 
 33.79 
 
 .95625 
 
 37.05 
 
 30.74 
 
 .95368 
 
 38.80 
 
 32.29 
 
 .95099 
 
 40.55 
 
 33.84 
 
 .95618 
 
 37.10 
 
 30.79 
 
 .95360 
 
 38.85 
 
 32.33 
 
 .95091 
 
 40.60 
 
 33.88 
 
 .95610 
 
 37.15 
 
 30.83 
 
 .95353 
 
 38.90 
 
 32.37 
 
 .95083 
 
 40.65 
 
 33.93 
 
 .95603 
 
 37.20 
 
 30.88 
 
 .95345 
 
 38.95 
 
 32.42 
 
 .95075 
 
 40.70 
 
 33.97 
 
 .95508 
 
 37.25 
 
 30.92 
 
 .95338 
 
 39.00 
 
 32.46 
 
 .95067 
 
 40.75 
 
 34.02 
 
 .95589 
 
 37.30 
 
 30.96 
 
 .95330 
 
 39.05 
 
 32.50 
 
 .95059 
 
 40.80 
 
 34.06 
 
 .95581 
 
 37.35 
 
 31.01 
 
 .95323 
 
 39.10 
 
 32.55 
 
 .95052 
 
 40.85 
 
 34.11 
 
 -.95574 
 
 37.40 
 
 31.05 
 
 .95315 
 
 39.15 
 
 32.59 
 
 .95044 
 
 40.90 
 
 34.15 
 
 .95567 
 
 37.45 
 
 31.10 
 
 .95307 
 
 39.20 
 
 32.64 
 
 .95036 
 
 40.95 
 
 34.20 
 
 .95560 
 
 37.50 
 
 31.14 
 
 .95300 
 
 39.25 
 
 32.68 
 
 .95028 
 
 41.00 
 
 34.24 
 
 .95552 
 
 37.55 
 
 31.18 
 
 .95292 
 
 39.30 
 
 32.72 
 
 .95020 
 
 41.05 
 
 34.28 
 
 .95545 
 
 37.60 
 
 31.23 
 
 .95284 
 
 39.35 
 
 32.77 
 
 .95012 
 
 41.10 
 
 34.33 
 
 .95538 
 
 37.65 
 
 31.27 
 
 .95277 
 
 39.40 
 
 32.81 
 
 .95004 
 
 41.15 
 
 34.37 
 
 .95531 
 
 37.70 
 
 31.32 
 
 .95269 
 
 39.45 
 
 32.86 
 
 .94996 
 
 41.20 
 
 34.42 
 
74 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 PERCENTAGE OF ALCOHOL (CONTINUED) 
 
 SPECIFIC 
 GKAVITY 
 
 AT|8F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT|8F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GKAVITY 
 
 AT|F. 
 
 ALCOHOL 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Pei- 
 cent 
 
 by 
 
 weight 
 
 Pel- 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 weight 
 
 0.94988 
 
 41.25 
 
 34.46 
 
 0.94704 
 
 43.00 
 
 36.03 
 
 0.94407 
 
 44.75 
 
 37.62 
 
 .94980 
 
 41.30 
 
 34.50 
 
 .94696 
 
 43.05 
 
 36.08 
 
 .94398 
 
 44.80 
 
 37.66 
 
 .94972 
 
 41.35 
 
 34.55 
 
 .94687 
 
 43.10 
 
 36.12 
 
 .94390 
 
 44.85 
 
 37.71 
 
 .94964 
 
 41.40 
 
 34.59 
 
 .94679 
 
 43.15 
 
 36.17 
 
 .94381 
 
 44.90 
 
 37.76 
 
 .94956 
 
 41.45 
 
 34.64 
 
 .94670 
 
 43.20 
 
 36.21 
 
 .94373 
 
 44.95 
 
 37.80 
 
 .94948 
 
 41.50 
 
 34.68 
 
 .94662 
 
 43.25 
 
 36.23 
 
 .94364 
 
 45.00 
 
 37.84 
 
 .94940 
 
 41.55 
 
 34.73 
 
 .94654 
 
 43.30 
 
 36.30 
 
 .94355 
 
 45.05 
 
 37.81) 
 
 .94932 
 
 41.60 
 
 34.77 
 
 .94645 
 
 43.35 
 
 36.35 
 
 .94346 
 
 45.10 
 
 37.93 
 
 .94924 
 
 41.65 
 
 34.82 
 
 .94637 
 
 43.40 
 
 36.39 
 
 .94338 
 
 45.15 
 
 37.98 
 
 .94916 
 
 41.70 
 
 34.86 
 
 .94628 
 
 43.45 
 
 36.44 
 
 .94329 
 
 45.20 
 
 38.02 
 
 .94908 
 
 41.75 
 
 34.91 
 
 .94620 
 
 43.50 
 
 36.48 
 
 .94320 
 
 45.25 
 
 38.07 
 
 .94900 
 
 41.80 
 
 34.95 
 
 .94612 
 
 43.55 
 
 36.53 
 
 .94311 
 
 45.30 
 
 38.12 
 
 .94892 
 
 41.85 
 
 35.00 
 
 .94603 
 
 43.60 
 
 36.57 
 
 .94302 
 
 45.35 
 
 38.16 
 
 .94884 
 
 41.90 
 
 35.04 
 
 .94595 
 
 43.65 
 
 36.62 
 
 .94294 
 
 45.40 
 
 38.21 
 
 .94876 
 
 41.95 
 
 35.09 
 
 .94586 
 
 43.70 
 
 36.66 
 
 .94285 
 
 45.45 
 
 38.25 
 
 .94868 
 
 42.00 
 
 35.13 
 
 .94578 
 
 43.75 
 
 36.71 
 
 .94276 
 
 45.50 
 
 38.30 
 
 .94860 
 
 42.05 
 
 35.18 
 
 .94570 
 
 43.80 
 
 36.75 
 
 .94267 
 
 45.55 
 
 38.35 
 
 .94852 
 
 42.10 
 
 35.22 
 
 .94561 
 
 43.85 
 
 36.80 
 
 .94258 
 
 45.60 
 
 38.39 
 
 .94843 
 
 42.15 
 
 35.27 
 
 .94553 
 
 43.90 
 
 36.84 
 
 .94250 
 
 45.65 
 
 38.44 
 
 .94835 
 
 42.20 
 
 35.31 
 
 .94544 
 
 43.95 
 
 36.89 
 
 .94241 
 
 45.70 
 
 38.48 
 
 .94827 
 
 42.25 
 
 35.36 
 
 .94536 
 
 44.00 
 
 36.93 
 
 .94232 
 
 45.75 
 
 38.53 
 
 .94810 
 
 42.30 
 
 35.40 
 
 .94527 
 
 44.05 
 
 36.98 
 
 .94223 
 
 45.80 
 
 ^38.57 
 
 .94811 
 
 42.35 
 
 35.45 
 
 .94519 
 
 44.10 
 
 37.02 
 
 .94214 
 
 45.85 
 
 38.02 
 
 .94802 
 
 42.40 
 
 35.49 
 
 .94510 
 
 44.15 
 
 37.07 
 
 .94206 
 
 45.90 
 
 38.66 
 
 .94794 
 
 42.45 
 
 35.54 
 
 .94502 
 
 44.20 
 
 37.11 
 
 .94197 
 
 45.95 
 
 38.71 
 
 .94786 
 
 42.50 
 
 35.58 
 
 .94493 
 
 44.25 
 
 37.16 
 
 .94188 
 
 46.00' 
 
 38.75 
 
 .94778 
 
 42.55 
 
 35.63 
 
 .94484 
 
 44.30 
 
 37.21 
 
 .94179 
 
 46.05 
 
 38.80 
 
 .94770 
 
 42.60 
 
 35.67 
 
 .94476 
 
 44.35 
 
 37.25 
 
 .94170 
 
 46.10 
 
 38.84 
 
 .94761 
 
 42.65 
 
 35.72 
 
 .94467 
 
 44.40 
 
 37.30 
 
 .94161 
 
 46.15 
 
 38.89 
 
 .94753 
 
 42.70 
 
 35.76 
 
 .94459 
 
 44.45 
 
 37.34 
 
 .94152 
 
 46.20 
 
 38.93 
 
 .94745 
 
 42.75 
 
 35.81 
 
 .94450 
 
 44.50 
 
 37.39 
 
 .94143 
 
 46.25 
 
 38.98 
 
 .94737 
 
 42.80 
 
 35.85 
 
 .94441 
 
 44.55 
 
 37.44 
 
 .94134 
 
 46.30 
 
 39.03 
 
 .94729 
 
 42.85 
 
 35.90 
 
 .94433 
 
 44.60 
 
 37.48 
 
 .94125 
 
 46.35 
 
 39.07 
 
 .94720 
 
 42.90 
 
 35.94 
 
 .94424 
 
 44.65 
 
 37.53 
 
 .94116 
 
 46.40 
 
 39.12 
 
 .94712 
 
 42.95 
 
 35.99 
 
 .94416 
 
 44.70 
 
 37.57 
 
 .94107 
 
 46.45 
 
 30.16 
 
PERCENTAGE OF ALCOHOL 
 
 75 
 
 PERCENTAGE OF ALCOHOL (CONCLUDED) 
 
 SPECIFIC 
 GRAVITY 
 AT f go F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT | F. 
 
 ALCOHOL 
 
 SPECIFIC 
 GRAVITY 
 
 AT f go F. 
 
 ALCOHOL 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 cent 
 by 
 weight 
 
 Per 
 cent 
 by vol- 
 ume 
 
 Per 
 
 cent 
 by 
 
 weight 
 
 0.04098 
 
 46.50 
 
 39.21 
 
 0.93870 
 
 47.75 
 
 40.37 
 
 0.93636 
 
 49.00 
 
 41.52 
 
 .1)4089 
 
 46.55 
 
 39.26 
 
 .93861 
 
 47.80 
 
 40.41 
 
 .93626 
 
 49.05 
 
 41.57 
 
 .94080 
 
 46.60 
 
 39.30 
 
 .93852 
 
 47.85 
 
 40.46 
 
 .93617 
 
 49.10 
 
 41.61 
 
 .94071 
 
 46.65 
 
 39.35 
 
 .93842 
 
 47.90 
 
 40.51 
 
 .93607 
 
 49.15 
 
 41.66 
 
 .94062 
 
 46.70 
 
 39.39 
 
 .93833 
 
 47.95 
 
 40.55 
 
 .93598 
 
 49.20 
 
 41.71 
 
 .94053 
 
 46.75 
 
 39.44 
 
 .93824 
 
 48.00 
 
 40.60 
 
 .93588 
 
 49.25 
 
 41.76 
 
 .94044 
 
 46.80 
 
 39.49 
 
 .93815 
 
 48.05 
 
 40.65 
 
 .93578 
 
 49.30 
 
 41.80 
 
 .94035 
 
 46.85 
 
 39.53 
 
 .93805 
 
 48.10 
 
 40.69 
 
 .93569 
 
 49.35 
 
 41.85 
 
 .94020 
 
 46.90 
 
 39.58 
 
 .93796 
 
 48.15 
 
 40.74 
 
 .93559 
 
 49.40 
 
 41.90 
 
 .94017 
 
 46.95 
 
 39.62 
 
 .93786 
 
 48.20 
 
 40.78 
 
 .93550 
 
 49.45 
 
 41.94 
 
 .94008 
 
 47.00 
 
 39.67 
 
 .93777 
 
 48.25 
 
 40.83 
 
 .93540 
 
 49.50 
 
 41.99 
 
 .9391)9 
 
 47.05 
 
 39.72 
 
 .93768 
 
 48.30 
 
 40.88 
 
 .93530 
 
 49.55 
 
 42.04 
 
 .93990 
 
 47.10 
 
 39.76 
 
 .93758 
 
 48.35 
 
 40.92 
 
 .93521 
 
 49.60 
 
 42.08 
 
 .93980 
 
 47.15 
 
 39.81 
 
 .93749 
 
 48.40 
 
 40.97 
 
 .93511 
 
 49.65 
 
 42.13 
 
 .93971 
 
 47.20 
 
 39.85 
 
 .93739 
 
 48.45 
 
 41.01 
 
 .93502 
 
 49.70 
 
 42.18 
 
 .93962 
 
 47.25 
 
 39.90 
 
 .93730 
 
 48.50 
 
 41.06 
 
 .93492 
 
 49.75 
 
 42.23 
 
 .93953 
 
 47.30 
 
 39.95 
 
 .93721 
 
 48.55 
 
 41.11 
 
 .93482 
 
 49.80 
 
 42.27 
 
 .93944 
 
 47.35 
 
 39.99 
 
 .93711 
 
 48.60 
 
 41.15 
 
 .93473 
 
 49.85 
 
 42.32 
 
 .93934 
 
 47.40 
 
 40.04 
 
 .93702 
 
 48.65 
 
 41.20 
 
 .93463 
 
 49.90 
 
 42.37 
 
 .93925 
 
 47.45 
 
 40.08 
 
 .93692 
 
 48.70 
 
 41.24 
 
 .93454 
 
 49.95 
 
 42.41 
 
 .93916 
 
 47.50 
 
 40.13 
 
 .93683 
 
 48.75 
 
 41.29 
 
 
 
 
 .93906 
 
 47.55 
 
 40.18 
 
 .93679 
 
 48.80 
 
 41.34 
 
 
 
 
 .93898 
 
 47.60 
 
 40.22 
 
 .93664 
 
 48.85 
 
 41.38 
 
 
 
 
 .93888 
 
 47.65 
 
 40.27 
 
 .93655 
 
 48.90 
 
 41.43 
 
 
 
 
 .93879 
 
 47.70 
 
 40.32 
 
 .93645 
 
 48.95 
 
 41.47 
 
 
 
 
SECTION XII 
 DETECTION OF COAL-TAR DYE 
 
 The use of coal-tar dyes in food and drink, while very 
 general, is quite unnecessary, and frequently constitutes 
 fraudulent adulteration. These dyes can usually be de- 
 tected by the following methods: 
 
 Double-Dyeing Process. Sostegni and Carpentieri. If a 
 solid or semisolid, dissolve 10 to 20 g. of the sample in 
 100 cc. of water. If a liquid, use from 50 to 100 cc., depend- 
 ing upon the intensity of the color. Acidify with 2 to 4 cc. 
 of 10 per cent HC1. Boil nun's veiling or other white 
 woolen cloth in very dilute KOH or strong soapsuds and 
 wash thoroughly. Boil a piece about 10 cm. square in the 
 dissolved sample until it has been well colored. This usually 
 takes from five to ten minutes. 
 
 Remove the cloth, wash in cold water, and boil in 2 per 
 cent HC1. After thorough rinsing dissolve the color in hot 
 dilute NH 4 OH (1 to 50). Remove the cloth and throw 
 it away. 
 
 Add a slight excess of HC1 to the ammonia solution. Im- 
 merse in this a second and smaller piece of cloth (2x3 cm.) 
 and boil. 
 
 If the dye is of vegetable origin, the second piece of wool 
 will be practically uncolored in the ammonia solution ; if 
 it is of coal-tar origin, it will take a decided tone, red, 
 pink, yellow, green, etc., depending upon the color of 
 the sample tested. 
 
 76 
 
DETECTION OF COAL-TAR DYE 77 
 
 Arata's Method. Dissolve 20 to 30 g. of the sample in 
 100 cc. of water and 10 cc. of a 10 per cent solution of 
 HKSO 4 . In this mixture boil a small piece of cloth which 
 has been previously boiled in dilute NaOH and thoroughly 
 washed in water. Remove, wash in water, and dry between 
 filter or blotting papers. 
 
 If the coloring matter is entirely of vegetable origin, the 
 wool will be uncolored or will take a faint pink or brown, 
 which is changed to green or yellow by ammonia and not 
 restored by washing. 
 
 In addition, double dye, as indicated in the previous 
 method. If the wool is still uncolored, the dye is of vege- 
 table origin. 
 
 Nun's veiling is a very suitable cloth for these experi- 
 ments. In removing the natural wool fat many students 
 make the mistake of boiling it in too strong caustic. A 
 1 per cent solution is sufficiently strong. 
 
 Cochineal and some vegetable colors dye wool directly, 
 hence the necessity of double dyeing. 
 
 Common substances which furnish excellent material for 
 coal-tar-dye testing are candy, soft drinks, wine, tablets, jam, 
 jelly, catsup, colored sugars, dessert powders, gelatin, etc. 
 
 Well-mounted pieces of wool dyed with these materials 
 and placed in the notebook give it a living interest. 
 
 Detection of Coal-Tar Dye in Butter. Melt a quantity of 
 butter the size of a marble in a test tube, being careful not 
 to scorch it. Add an equal volume of Low's reagent and 
 shake vigorously. Heat nearly to boiling and set aside. 
 After the acid has settled it will be wine, red in the pres- 
 ence of azo colors. Pure butter fat gives only a faint bluish 
 tinge. (Low's test.) 
 
 Low's Reagent. HC 2 H 3 O 2 , 4 parts; H 2 SO 4 , 1 part. Mix. 
 
78 ELEMENTARY APPLIED CHEMISTRY 
 
 Martin's Test. Shake 5 g. of the butter in a test tube 
 with 20 cc. of Martin's reagent. Let the mixture stand 
 until the fat has settled to the bottom of the tube. The 
 dye, if present, will color the supernatant liquid yellow. 
 
 Martin's Reagent. CS 2 , 4 cc. ; C 4 H 5 OH, 30 cc. Mix. 
 
 Acid and Alkali Test. Melt about 20 g. of the butter in 
 an evaporating dish and set on a water bath until the curd 
 and contained water have entirely separated. Pour off the 
 clear, supernatant fat and filter it through a dry filter paper 
 in a hot- water funnel or in an oven at 60 C. If the fat is 
 not clear, it must be filtered again. 
 
 Pour into each of two test tubes 2 g. of this filtered 
 fat dissolved in ether. Into one of the tubes pour 1 cc. of 
 HC1 and into the other the same volume of 10 per cent 
 KOH. Shake the tubes well and allow to stand. In the 
 presence of azo dye the test tube to which the acid has been 
 added will show a pink to wine-red coloration, while the 
 alkaline solution in the other tube will show no color. If 
 annatto or other vegetable color has been used, the potash 
 solution will be colored yellow {Bulletin No. 107). 
 
 Coal-Tar Dye in Lemon Extract. Lythgoe's Test. To the 
 original sample add two or three drops of strong HC1. 
 
 No change indicates natural color, turmeric, or naphthol 
 colors. 
 
 Pink indicates tropseolin or methyl orange. 
 
 Partial decoloration indicates Martin's yellow. 
 
 Complete decoloration indicates dinitro-cresols. 
 
 Evaporate 10 to 20 cc. of the sample to dryness, dissolve 
 the residue in water, and employ the test of Sostegni and 
 Carpentieri. 
 
 Why are flavoring extracts often artificially colored ? 
 
SECTION XIII 
 IDENTIFICATION OF VEGETABLE COLOES 
 
 Caramel. Amthor's Test. Place 10 cc. of the suspected 
 solution in a Nessler tube or narrow clear-glass bottle. Add 
 from 30 to 50 cc. of paraldehyde, the latter volume if the 
 color is very dark. To make the solutions mix, introduce a 
 few cubic centimeters of absolute alcohol. 
 
 If caramel is present, a yellow to dark-brown precipitate 
 will fall to the bottom of the tube. 
 
 Fuller' s-Earth Method. Shake 50 cc. of the solution with 
 25 g. of fuller's earth. Allow the mixture to stand in a 
 corked bottle of about 2 in. diameter for an hour at room 
 temperature. 
 
 The caramel will be absorbed by the earth, and the super- 
 natant liquid will appear more or less clear, depending upon 
 the amount of the absorption. 
 
 As some fuller's earth absorbs color more readily than 
 others, it is advisable to experiment with different samples 
 upon solutions known to contain caramel. 
 
 Amyl-Alcohol Method. Shake 5 cc. of the solution with 
 10 cc. of amyl alcohol in a small vial for a minute or so. 
 Allow the liquids to separate. 
 
 If caramel is present, the upper layer will be decolorized 
 to a greater or less extent. The lower layer will be colored 
 in proportion to the amount of caramel in the solution. 
 
 Test vanilla extract, whisky, ginger ale, soft drinks, and 
 the like for caramel. 
 
 79 
 
80 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 Cochineal. Grirard and Dupres Method. If the sample is 
 catsup, canned fruit, or of this nature, triturate in a mortar 
 with water until it is reduced to a 
 very thin paste. Filter, acidulate 
 with HC1, 'and shake with amyl 
 alcohol. If cochineal is present, the 
 alcohol will be colored yellow or 
 orange. Separate the amyl alcohol 
 and wash it with water until neutral. 
 Add, drop by drop, a very dilute 
 solution of uranium acetate. In the 
 presence of cochineal a beautiful 
 emerald-green color is produced. 
 
 Turmeric. Extract the color with 
 alcohol. Saturate a filter paper with 
 the extract and dry at 100 C. Dip 
 the paper in a dilute solution of 
 boric acid to which a few drops 
 of 10 per cent HC1 have been 
 added. Dry the paper. Turmeric 
 is indicated by a distinct cherry-red 
 coloration. Add a drop of alkali and olive-green will de- 
 velop (Bulletin No. 51, United States Bureau of Chemistry, 
 p. 131). 
 
 FIG. 17. True and artifi- 
 cial whisky treated with 
 amyl alcohol 
 
 Caramel shows in the hot- 
 torn of the right-hand hottie. 
 The supernatant liquid is 
 decolorized 
 
SECTION XIV 
 RAFFIA DYEING 
 
 Raffia is the cuticle of the leafstalks of the Madagascar 
 palm (Raffia mffia). Its tissue is cellulose for the most 
 part, so the method of dyeing must necessarily differ from 
 the method followed in dyeing wool, silk, or other animal 
 fabrics. 
 
 A mordant is a substance to "set" a color; that is, to 
 make the pigment unite chemically, or in some cases physi- 
 cally, or both, with the material dyed. The principal mor- 
 dants used in raffia dyeing are alum and other aluminium 
 salts, and certain salts of iron, tin, and copper. 
 
 Raffia is soaked in the mordant solution until thoroughly 
 impregnated, and then boiled in a solution of the dye, which 
 forms with the mordant a metallic colored substance known 
 as a " lake.-' A lake is relatively insoluble and cannot be 
 easily washed out. 
 
 General Principles. Alum should be used as a mordant 
 unless otherwise specified. Dissolve 1/4 Ib. in 10 qt. of 
 water. Let the raffia stand in this solution until it has 
 become thoroughly saturated. From six to twenty-four 
 hours is generally sufficient. Always untie the bundles 
 and do them up loosely. 
 
 Raffia should not be dry when placed in the dye. Either 
 take it directly from the mordant or wet it thoroughly 
 with water. Let the dye be boiling when the raffia is 
 placed in it. 
 
 81 
 
82 ELEMENTARY APPLIED CHEMISTRY 
 
 Alum spots, grayish patches on the finished product, are 
 not generally disadvantageous. Most autumn foliage has 
 a white fungus which, in general appearance, these spots 
 resemble. A dip in warm water will remove them. Colors 
 obtained as herein directed will compare favorably with the 
 bright, soft colors of autumn or the fresh tints of spring. 
 
 Do not dye too dark. Lighter tints are more pleasing in 
 woven and braided work. Dye slightly darker than desired, 
 as the raffia is lighter when dried. Test pieces may be 
 quickly dried by holding them against the side of the hot 
 dye pan. This saves time and affords a convenient means 
 of judging color value. 
 
 Strong dye and short boiling makes soft, flexible, tough 
 raffia. Weak dye and long boiling makes harsh, brittle 
 raffia. Some of the coal-tar dyes leave the material glossy, 
 harsh, and brittle. Fifteen minutes should be the maximum 
 time of boiling. 
 
 Vegetable dyes, in general, give soft, pleasing tones. 
 Coal-tar dyes give bright, glossy colors. 
 
 Rinse before putting into a dye of another color. Dull, 
 passive colors may be brightened by boiling in fresh or 
 stronger dye. Weak dye is of little value. Keep the raffia 
 well covered with dye, and turn frequently. 
 
 Dyes extracted from bark, leaves, fruit, roots, vegetables, 
 wood, and the like should be carefully strained before using. 
 
 Save the waste dye, as many beautiful effects may be pro- 
 duced from it. It is not only economical to use this dye, 
 but interesting to discover the different colors that may be 
 obtained. 
 
 Time directions are only approximate, as much depends 
 upon the quality and strength of the dye and on the kind 
 and amount of mordant absorbed. 
 
RAFFIA DYEING 83 
 
 The outer side of the raffia will take a brighter tone than 
 the inner side. This is especially noticeable in green and 
 orange tones. 
 
 Do not place the full amount of raffia in the pan at 
 once. Dye a small piece and see if the color suits you. Do 
 not throw away the material which is displeasing in color, 
 as it may easily be dyed black or brown. 
 
 Experiment by mixing small quantities of various dyes 
 and mordants in cups and test tubes. You will doubtless 
 discover some new and pleasing combination. 
 
 Material will absorb only a certain amount of the dye. 
 This amount absorbed, the pigment point is reached. Do 
 not expect to pour a quart of water at once into a pint cup. 
 
 Dye pans should be large enough for the work at hand. 
 The four-quart or eight-quart size is convenient. The best 
 results are obtained by using enamel ware. 
 
 Preparation of Dyes and Mordants. Dyes and mordants 
 should be prepared in the following manner : 
 
 Butternut. Fill a four-quart pan half full of the husks ; 
 green ones give the softest tones ; the shells are not objec- 
 tionable. Cover with water and boil for fifteen minutes. 
 
 Cardinal Red. Dissolve a mass the size of a cranberry in 
 a gallon of water. 
 
 Copper Sulfate. Two ounces to a quart of water. 
 
 Elderberries. Berries, 1 part ; water, 3 parts. 
 
 Fustic Chips. A teacupful to 4 qt. of water. Boil ten 
 minutes. 
 
 Fustic Extract. Dissolve a piece the size of a walnut in a 
 gallon of water. 
 
 Iron Sulfate. Two ounces to a quart of water. Always 
 use this solution in an old dish, as it will soon ruin a 
 new one. 
 
84 ELEMENTARY APPLIED CHEMISTEY 
 
 Indigo. Use indigo paste (sulfate of indigo). Dissolve a 
 mass the size of two shoe buttons in 4 qt. of water. 
 
 Logwood Chips. See Fustic Chips. 
 
 Logwood Extract. See Fustic Extract. 
 
 Leaves. Fill a four-quart pan full of the shredded leaves 
 well pressed down. Cover with water, and boil. Replenish 
 the water from time to time until the dye appears highly 
 colored. The usual time is about fifteen minutes. 
 
 Onion Skins. The outer skins from half a dozen medium- 
 sized onions will furnish yellow dye for half a pound of 
 raffia. Boil until the color is extracted. The time required 
 is about ten minutes. 
 
 Potassium Ferri-cyanide (Red Prussiate of Potash'). Two 
 ounces to a quart of water. 
 
 Potassium Bichromate. Dissolve 1 oz. in a quart of water. 
 This solution used with red dulls it and gives an orange 
 tone. 
 
 Sumac. Three quarts of the broken cones. Keep well 
 covered with water and boil for twenty minutes. 
 
 Walnut. See Butternut. 
 
 Specific Directions for obtaining the Following Colors : 
 
 Black. 1. Dye heavily with logwood and place imme- 
 diately, without rinsing, into a strong, hot FeSO 4 solution. 
 
 2. Dye as. above, substituting oak leaves for the logwood. 
 
 Blue. Dye unmordanted raffia in indigo solution to which 
 two or three drops of H 2 SO 4 have been added. Dry in 
 direct sunlight. The brighter the light, the bluer the color. 
 Many tones can be produced by dyeing for different lengths 
 of time in this solution. 
 
 Blue-Green. 1. Boil mordanted raffia in plain indigo solu- 
 tion and dry away from the sunlight. Raffia dyed with indigo 
 must be thoroughly rinsed to remove all traces of acid. 
 
KAFFIA DYEING 85 
 
 2. Dye in potassium ferri-cyanide to which a few drops 
 of H 2 SO 4 have been added and mixed thoroughly. 
 
 3.. Dye as in 2, and place directly into hot iron sulfate. 
 
 Brown. 1. Boil in dye from maple leaves until thoroughly 
 colored. Remove, rinse, and wring out the superfluous 
 liquid. Then boil in a dye prepared as follows : Strong 
 butternut dye to which has been added 1/2 pt. of K 2 Cr 2 O 7 
 solution and an equal amount of cardinal-red solution. 
 
 2. First dye in redwood solution and immerse for about 
 three minutes in hot, strong logwood. 
 
 Light Brown. 1. Boil in clear butternut dye. 
 
 2. Boil in clear maple dye. 
 
 3. Dye green with fustic and indigo, q.v., and then boil 
 in a solution of CuSO 4 . 
 
 Chocolate-Brown. Dye in sumac and treat with FeSO 4 . 
 
 Dark-Brown. Boil in butternut and then in K 2 Cr 2 O ? . 
 
 Gray-Brown. Equal amounts of sumac, maple, and oak 
 leaves make a green-brown dye. Since red is the comple- 
 ment of green, and combined with it makes gray, add 
 sufficient logwood to bring to the desired shade. 
 
 Olive-Brown. Boil for six minutes in dye from walnut 
 husks. 
 
 Red-Brown. 1. Add a teaspoonful of alum to walnut 
 dye and boil in the resulting solution for ten minutes. 
 
 2. Dye with cardinal and then with logwood. 
 
 3. (a) Dye in redwood solution. 
 
 (6) Then dye in a solution made from fustic chips, 3 parts, 
 and logwood chips, 1 part. 
 
 Yellow-Brown. Boil first in a dye from maple leaves and 
 then in K 2 Cr 2 O ? . 
 
 Green. Bright Gf-reen. Dye yellow with fustic and onion 
 skins. Place immediately in a strong, hot solution of 
 
$6 ELEMENTARY APPLIED CHEMISTRY 
 
 indigo. Dull with iron sulf ate to the desired shade. Nearly 
 all tones can be produced by this method. 
 
 Dull G-reen. Dye with black birch leaves. 
 
 Dark Green. Dye with the birch and dip into FeSO 4 . 
 
 Gray- G-reen. Add sufficient ammonia to elderberry juice 
 to turn it a pronounced green. Boil the raffia in this solu- 
 tion until the desired shade is produced. The time required 
 is about eight minutes. 
 
 Olive- G-reen. See Dark Green. Boil longer in the iron 
 sulfate solution. If left too long, the raffia acquires a heavy 
 olive tone not pleasing to the eye. 
 
 Yellow- Green. Color with fustic or onion skins and very 
 slightly with indigo. 
 
 Gray. For these effects in general, boil in dye from 
 sumac cones with the stems. A dip in iron sulfate will 
 produce a pleasant neutral effect. 
 
 Old Rose. Dye with sumac berries, discarding all stems. 
 Substitute elderberries for the sumac. 
 
 Orange. 1. Dye in fustic and then in strong, hot redwood 
 infusion. 
 
 2. Boil in butternut for about six minutes. Rinse and 
 dip into cardinal solution. 
 
 To produce a peculiar but pleasing effect, dye first in 
 fustic and then in cardinal. One side will be brown yellow, 
 the other a dark red. 
 
 Red. With infusions of redwood it is possible to get an 
 almost complete color scale, from a deep, rich, dark red to 
 a pale orange. These colors can be dulled with FeSO 4 , 
 thus producing an infinite variety of tints and shades. 
 
 For a deep red a very strong solution is needed, and only 
 a small quantity of material can be colored at a time. As 
 the strength is reduced the color tends toward orange. 
 
KAFFIA DYEING 87 
 
 The lighter tints of orange can be dulled with iron sul- 
 fate to give a pleasing light brown, practically identical 
 with that produced from sumac. 
 
 Bright Red. Dye in sumac and strengthen in cardinal, 
 or dye directly in the cardinal. 
 
 Dark Red. 1. Dye a bright red and dip in iron sulfate. 
 The longer it remains the darker it becomes, until the limit 
 is reached. 
 
 2. Dye brown with waste dye and then boil in cardinal. 
 
 Indian Red. 1. Dye orange red and boil in CuSO 4 for 
 two minutes. 
 
 2. Dye light brown and boil first in cardinal solution 
 and then in potassium dichromate. 
 
 3. To butternut dye add half as much cardinal solution, 
 one eighth as much K 2 Cr 2 O 7 , one fourth teaspoonful of 
 indigo paste, 2 oz. of logwood chips. Boil and strain, and 
 dye the raffia in the clear liquid. 
 
 4. To produce a pale shade, dye in an extra strong solu- 
 tion from the sumac berries after discarding the stems. 
 
 Purple-Red. Dye in cardinal and then in indigo, or dye 
 alum-mordanted raffia in logwood. 
 
 Yellow. Any of the yellow tones may be intensified by 
 longer boiling. 
 
 Lemon Yellow. 1. Boil in dye from pear leaves to which a 
 spoonful of alum has been added. Alum intensifies the color. 
 
 2. Boil for one minute in fustic, or for the same length 
 of time in onion skins. 
 
 Any of the colors herein described can be duplicated, 
 provided the experimenter becomes familiar with the special 
 dye at hand. 
 
 Raffia dyeing is not merely a mechanical process ; it is 
 an art learned best by the patient and orderly worker. 
 
SECTION XV 
 
 CHEMISTRY OF STAINS 
 
 A stain may be caused by the union, chemical or physi- 
 cal, or both, of some substance with a suitable medium, as 
 paper, cloth, skin, and the like. The subject is a very deep 
 and intricate one. 
 
 When a stain is purely physical, as, for example, a spot 
 of grease on cloth, physical means of removing it are best ; 
 that is, some simple process of absorption or solution. 
 
 When the stain is of a chemical nature and certain oxids 
 are formed, take, for example, the stain of apple juice on 
 cloth, chemical means must be employed to reduce or 
 "bleach" the oxid. 
 
 When a stain is of both a chemical and physical nature, 
 both physical and chemical means should be employed to 
 remove it. A stain of this character may be illustrated by 
 an ink spot on cloth. 
 
 A good general bleaching reagent consists of a double 
 solution kept in separate bottles. 
 
 No. 1. Acetic or tartaric acid solution, 20 per cent. 
 No. 2. Five grams of bleaching powder (CaClO x ). Boil in 100 cc. 
 of water until a pink color appears. Filter and add 50 cc. of cold water. 
 
 This combination is sometimes called " ink eradicator." It 
 must not be applied to silk or to fabrics of delicate color. 
 
 To remove stains of ink, coffee, tea, fruit, and dye, wet 
 the spot thoroughly with No. 1. Absorb the superfluous 
 liquid with a blotter and apply No. 2. Rinse and repeat, 
 
 88 
 
CHEMISTRY OF STAINS 
 
 89 
 
 if necessary. If a persistent, yellowish spot remains, as is 
 often the case when woolen goods have been treated, 
 remove all traces of the reagents and saturate with fresh 
 H 2 O 2 . Common stains may be removed by treating as 
 shown in the following table : 
 
 STAIN 
 
 REMOVED BY 
 
 Acids . . . . 
 Grass and fruit 
 Grease 
 
 Dyes, coal-tar or of vege- 
 table origin .... 
 Mildew ...... 
 
 Inks 
 
 Inks, indelible (silver) . 
 
 lodin 
 
 Iron rust 
 
 Paint, varnish .... 
 Tar, wagon grease . . 
 
 Cold water, Nos. 1 and 2 
 
 Cold water, alcohol, Nos. 1 and 2 
 
 Gasoline, carbon tetrachlorid, chloroform, 
 ether, carbon bisulfid, ammonia, soapsuds, 
 warm fuller's earth (cover with a blotter 
 and apply a warm flatiron) 
 
 Nos. 1 and 2, ammonia 
 
 Nos. 1 and 2, sunlight 
 
 Nos. 1 and 2 
 
 Potassium cyanide, 10 per cent. Use great 
 
 caution, intensely poisonous. Sodium hypo- 
 
 sulfite, 20 per cent 
 Methyl alcohol, potassium iodid solution, 
 
 10 per cent 
 Warm oxalic or citric acid, 10 per cent. If in 
 
 silk, let it alone 
 Turpentine, benzine, carbon tetrachlorid. Use 
 
 no turpentine on silk 
 Soap and oil, turpentine 
 
SECTION XYI 
 
 FOOD PKESERVATIVES. 
 
 Detection of Sulfurous Acid. Weigh about 25 g. of the 
 sample into a 200-cc. Erlenmeyer flask. Add water, if nec- 
 essary, to form a thin paste 
 and about 5 g. of sulfur-free 
 zinc. Introduce 10-20 cc. 
 chemically pure HC1. Over 
 the mouth of the flask place 
 a small filter paper which 
 has been wet with a strong 
 solution of Pb (NO 8 ) 2 . Heat 
 gently. The blackening of 
 the filter paper indicates the 
 presence of sulfites. Why ? 
 A mere browning of the filter 
 paper should not be accepted 
 as evidence of the inten- 
 tional addition of SO 2 , either 
 as a preservative or as a 
 bleaching agent ; it must be 
 distinctly black. (Bulletin 
 No. 107, p. 187.) 
 
 Distillation Method. Leach. 
 Reduce 100-200 g. of the 
 sample to paste as before, 
 and acidify with 5 cc. of 
 90 
 
 FIG. 18. Apparatus arranged for 
 
 the detection of sulfurous acid by 
 
 the distillation method 
 
FOOD PRESERVATIVES 91 
 
 20 per cent phosphoric acid. Transfer to a boiling flask and 
 distil. Arrange the apparatus so that the outlet of the con- 
 denser will dip below the surface of a little water, about 20 cc. 
 
 Distil off 20 to 30 cc. Treat the distillate with 5 to 10 cc. 
 of bromin water and boil for a minute or so. 
 
 Without waiting for the distillate to cool, add a little 
 BaCl 2 . A white precipitate indicates sulfurous acid. 
 
 What is this precipitate ? Test its solubility. Of what 
 use is the bromin water ? 
 
 Test molasses, lime juice, mushrooms, Hamburg steak, 
 sausage, etc. for sulfurous acid. 
 
 Determination of Sulfurous Acid by Direct Titration. Care 
 must be taken in applying this method to other products 
 than wine to determine whether the iodin is decolorized by 
 any substance that may naturally be present. 
 
 Macerate 25 g. of the sample, if a solid or semisolid, with 
 sufficient water to form a thin paste. Place in a 200-cc. Erlen- 
 meyer flask. Add 25 cc. of normal KOH, mix thoroughly, 
 and allow it to stand for fifteen minutes, shaking from time 
 to time. Add 10 cc. of dilute sulfuric acid (1 to 3) and 5 cc. 
 of freshly prepared starch solution. Rapidly titrate the mix- 
 ture with N/50 iodin solution until a blue color is perma- 
 nent for several minutes. 
 
 One cubic centimeter of N/50 iodin solution is equivalent 
 to 0.00064 gram of sulfur dioxid. 
 
 From the per cent of SO 2 calculate the per cent of sulfur- 
 ous acid in the original sample (Bulletin No. 107, p. 188). 
 
 Detection of Boron Compounds Borax or Boric Acids. It 
 is not uncommon to find this forbidden preservative in 
 cheese, ice-cream cones, fancy crackers and biscuits. It was 
 formerly used in canned meats, but the practice has greatly 
 declined of late. 
 
92 ELEMENTARY APPLIED CHEMISTRY 
 
 : ' The common symptoms observed after long-continued 
 doses of borax or boric acid in food are headaches, sensations 
 of fullness in the head, uneasiness and nausea in the stomach, 
 and disturbances of the digestion and appetite" (Wih'i/). 
 
 Discover the Effects of H 3 B0 3 upon Turmeric Paper and 
 Turmeric Tincture. Break about 10 g. of saltines or other 
 crackers into a crucible. Add a pinch of boric acid or borax, 
 and ash. Acidulate the ash with a drop or so of HC1 and 
 dissolve in as little water as possible. 
 
 (a) Dip a strip of turmeric paper in the solution and 
 allow it to dry. Result ? 
 
 (6) Mix the remainder of the ash solution with a cubic 
 centimeter of turmeric tincture in a watch glass and evapo- 
 rate over a water bath. Result ? 
 
 Confirm both () and (6) by placing a drop of dilute 
 alkali upon the paper or on the contents of the glass. An 
 olive-green color should appear. 
 
 After becoming familiar with the reaction between boric 
 acid and turmeric, test crackers or biscuits, butter, cheese, 
 canned meat, and shrimps for boron compounds. 
 
 Method. Ash about 10 g. of the sample, first adding 
 enough limewater to make an alkaline reaction. Acidulate 
 the ash with a drop or two of HC1. Dissolve in a few 
 drops of water. Test with the turmeric paper and with the 
 turmeric tincture, as outlined. 
 
 If the turmeric is reddened by the solution of the ash 
 and turned olive-green by dilute alkali, boric acid, free or 
 combined, is present in the sample. 
 
 Boron Compounds in Butter. Melt 25 g. of the sample 
 on a water bath and allow the aqueous solution to settle. 
 Decant this solution and acidulate with a drop or so of dilute 
 HC1. From this point apply the regular turmeric test. 
 
FOOD PRESERVATIVES 
 
 93 
 
 Detection .of Salicylic Acid (HC 7 H 5 3 ). This compound 
 has been used for the preservation of catsup, jams and 
 other fruit products, and beer. Reduce the sample to a 
 thin paste with water, if it is not 
 already a liquid. Acidify slightly 
 with dilute H 2 SO 4 . Shake with an 
 equal volume of chloroform in a 
 closed flask or separatory funnel. 
 Separate the chloroform and allow 
 it to evaporate spontaneously. 
 
 First Test. To a part of the 
 dry residue add a drop of ferric 
 chlorid and an equal volume of 
 water. A pronounced violet or 
 purple color indicates the pres- 
 ence of salicylic acid. 
 
 Second Test. Heat the remainder 
 of the residue gently with a few 
 drops of 20 per qent H 2 SO 4 and 
 a cubic centimeter of methyl 
 alcohol. 
 
 If salicylic acid is present, 
 
 a pronounced odor of " winter- 
 
 FIG. 19. Separatory funnel 
 
 green," or methyl salicylate, will f or extracting salicylic or 
 be apparent. benzoic acid with ether or 
 
 Detection' of Benzoic Acid chloroform 
 
 . Sublimed crystals of benzoic 
 
 (HC 7 H 6 2 ). Benzoic acid is used acid show on the wate h glass. 
 for much the same purpose as 
 
 salicylic acid, and is more often found in food products. 
 Extract the sample as for salicylic acid and evaporate 
 the chloroform. Dissolve a part of the dried residue in 
 ammonia and evaporate to dryness over a water bath. 
 
94 
 
 ELEMENTARY APPLIED CHEMISTRY 
 
 First Test Dissolve in a few drops of water, heating 
 gently to effect the solution. Filter into a small test tube 
 and add a drop of ferric chlorid. A flesh-colored precipi- 
 tate of ferric benzoate assures the presence of benzoic acid. 
 
 Second Test. Dissolve the 
 remainder of the chloroform 
 extract in ammonia and evap- 
 orate to dryness in a two-inch 
 watch glass. Invert a second 
 watch glass over the first. 
 Between these insert a fil- 
 ter paper from the center of 
 which has been cut a half- 
 inch circle. Clamp the watch 
 glasses closely together and 
 heat at a low temperature 
 on a sand bath. If benzoic 
 acid is present, needlelike 
 crystals will sublime on the 
 upper watch glass. Examine 
 them with a low-power lens. 
 Dissolve and treat them with 
 a drop of ferric chlorid, as 
 in the preceding test. 
 
 Detection of Saccharin. Prepare the sample as for the 
 salicylic acid. test. Extract with ether and allow the latter 
 to evaporate at room temperature. A distinctly sweet taste 
 indicates the presence of saccharin. 
 
 Add a small piece of NaOH and heat gently. The sac- 
 charin will be converted into salicylic acid and can be 
 detected by the ferric chlorid test. 
 
 FIG. 20. Sand bath, filter paper, 
 
 and double watch glass arranged to 
 
 sublime benzoic acid 
 
SECTION XVII 
 
 EXAMINATION OF TOOTH POWDEES 
 
 The usual ingredients of these dentifrices are soap pow- 
 der, precipitated chalk (CaCO 3 ), sugar, orris root, and other 
 flavoring materials. 
 
 Sometimes powdered pumice stone and cuttlefish bone are 
 substituted for the chalk. Since these substitutes scratch 
 the enamel, they are injurious and should be avoided. They 
 may be detected as follows : 
 
 Shake up 1 to 2 g. of the powder with 10 cc. of dilute 
 alcohol. To the residue add about 4 cc. of HC1 and an 
 equal volume of water. Note any effervescence. Boil. 
 Allow any undissolved matter to settle and decant the 
 solution. Insoluble matter indicates pumice stone. Con- 
 firm by placing a little on a glass plate and rubbing gently 
 with a glass rod. If pumice is present, a scratching sound 
 will be heard. 
 
 Divide the decanted solution into two parts. 
 
 The First Part. Evaporate to dryness and test with 
 ammonium molybdate for the PO 4 radical. If present, 
 cuttlefish bone is indicated. 
 
 The Second Part. Test for calcium with (NH 4 ) 2 C 2 O 4 . 
 Its presence is indicated by a flocculent white precipitate. 
 This further bears out the suggestion of the presence of 
 powdered bone. 
 
 95 
 
96 ELEMENTARY APPLIED CHEMISTRY 
 
 TABLE OF INDICATIONS 
 
 EFFERVESCENCE 
 
 RESIDUE INSOL- 
 UBLE IN HC1 
 
 CALCIUM 
 
 P0 4 
 
 INDICATION 
 
 Yes 
 
 No 
 
 Yes 
 
 No 
 
 Chalk 
 
 Yes 
 
 No 
 
 Yes 
 
 Yes 
 
 Cuttlefish bone 
 
 No 
 
 Yes 
 
 No 
 
 No 
 
 Pumice 
 
 Yes 
 Yes 
 
 . Yes 
 Yes 
 
 Yes 
 Yes 
 
 No 
 Yes 
 
 Chalk and pumice 
 Cuttlefish bone 
 
 
 
 
 
 and pumice 
 
 What are the indications for chalk and cuttlefish bone ? 
 In addition to the above tests, determine the free and 
 combined alkali and the alkaline carbonates. 
 
SECTION XVIII 
 EXPERIMENTS WITH GLUCOSE 
 
 Glucose is widely distributed in the vegetable kingdom. 
 It occurs naturally in many fruits and vegetables, in honey, 
 in the blood, liver, and urine. In the disease diabetes mel- 
 litus the quantity present in the urine is sometimes as high 
 as 10 per cent. 
 
 It is artificially prepared on a large scale by treating 
 corn or potato starch with dilute sulfuric acid. Its sweet- 
 ness to that of sugar is as 3 to 5. Large quantities are 
 annually consumed in the manufacture of leather, candy, 
 table sirups, jams, jellies, and the like. 
 
 Conversion of Starch into Glucose. Boil 5 to 10 g. of 
 sawdust, filter paper, cotton rags, or cornstarch, with a 
 10 per cent solution of H 2 SO 4 in an Erlenmeyer flask, in 
 the neck of which is a funnel to act as a reflux condenser. 
 Continue boiling until the liquid becomes a decided yellow 
 or brown. Neutralize with powdered chalk and filter. 
 Evaporate the filtrate to a thick sirup. 
 
 Suggestions. Pour the acid into the water. 
 
 Flasks will break if the starch is allowed to stick to 
 the bottom. For the first attempt use corn or potato 
 starch. 
 
 Replenish the water as it boils away. If the acid becomes 
 too strong, it will carbonize the starch. 
 
 Neutralize by adding the chalk well powdered. Test 
 often with litmus. Filter. If the filtrate is still acid, add 
 
 97 
 
98 ELEMENTARY APPLIED CHEMISTRY 
 
 more of the carbonate. A relatively large quantity will 
 probably be required. 
 
 Add plenty of water to the filter to wash the glucose 
 from the spent carbonate. 
 
 Great care must be taken during the process of evapora- 
 tion or the liquid will blacken. Stir constantly and finish 
 over a water bath. 
 
 Reactions. Notice the interesting exhibition of catalysis in 
 the following reaction : 
 
 C 6 H 10 6 + H 2 = C 6 H 12 6 . 
 
 starch glucose 
 
 C 6 H 12 6 and H 2 SO 4 + CaCO 3 = ? 
 
 Name the contents of the filter paper. Dry it. It will 
 keep its form. Why ? Which of the changes in the above 
 experiment are physical, and which are chemical ? 
 
 Test for Glucose by the Reduction of a Copper Salt. Dis- 
 solve a little glucose in water. Add 2 cc. Fehling's solu- 
 tion, 1 cc. each of No. 1 and No. 2. Heat nearly to boiling. 
 The result is characteristic. 
 
 Repeat, substituting cane sugar for the glucose. Result ? 
 
 Fehling's Solution, No. 1 : CuSO 4 , 34.6 g. ; water, 500 cc. 
 Fehling's Solution, No. 2 : llochelle salts, 173 g. ; NaOH, 50 g. ; 
 water, 500 cc. Keep in separate bottles. 
 
 Test for Glucose by the Precipitation of Dextrine. Dis- 
 solve a little glucose in water. To two or three cubic centi- 
 meters add a large excess of methyl alcohol. Agitate. The 
 glucose is precipitated as dextrine. 
 
 Repeat, substituting cane sugar for glucose. Result ? 
 
 Inversion of Cane Sugar. Make a solution of cane sugar 
 as before. Add one drop of HC1 and .boil vigorously. Test 
 with Fehling's solution. 
 
 B H M U + H 2 = C 6 H 12 6 + C.H U 0, 
 
 oane sugar glucose fructose 
 
EXPERIMENTS WITH GLUCOSE 99 
 
 The mixture of glucose and fructose is called invert 
 sugar. Notice how the inversion is brought about by hydrol- 
 ysis. Before cane sugar is digested it must pass through 
 the process of inversion. 
 
 Test honey, confectionery, maple sirup, molasses, jam, 
 jelly, the contents of pies and cake fillers for invert sugar 
 by the Fehling method. 
 
 Test the same for glucose by the precipitation of dextrine. 
 It is instructive to treat a sample of homemade jelly and 
 any one of the cheap varieties by this method. A decided 
 milkiness in the alcohol indicates commercial glucose. 
 
 Many soft candies, waxes, taffies, a large proportion of 
 stick candy, caramels, and the like are made with glu- 
 cose. Sometimes a little cane sugar is added to give it a 
 sweeter taste. 
 
 Considerable glucose is used in the manufacture of table 
 sirups. These are sent to the market under euphonious 
 names, as "Maple Drip," "Bon Ton," "Golden Drip," 
 " White-Loaf Drip," etc. 
 
 Detection of Glucose in Honey. Dissolve one part of honey 
 in an equal volume of water. Cool and add 5 to 8 drops of 
 a dilute solution of iodin in KI. 
 
 If the honey solution remains a pale yellow, commer- 
 cial glucose is probably absent. If decolorized, glucose is 
 indicated. 
 
 If starch is present, the characteristic blue-to-purple 
 coloration will appear (Beckmaris test). 
 
 Anilin-Acetate Test for Artificial Invert Sugar in Honey. 
 The reagent must be freshly prepared. Shake 5 cc. of 
 chemically pure anilin with 5 cc. of water, and add 2 cc. of 
 glacial acetic acid. The milky emulsion of anilin and water 
 should clear up perfectly upon the addition of the acid. 
 
100 ELEMENTARY APPLIED CHEMISTRY 
 
 Dissolve about 5 cc. of honey in a test tube with an equal 
 volume of water, and pour a little of the anilin solution 
 down the sides of the tube so as to form a thin layer upon the 
 surface of the liquid. If artificial invert sugar is present, a 
 red ring will form beneath this layer, and on gently agitat- 
 ing the tube all of the acetate will be tinged this color. 
 
 If the honey is pure and has not been overheated, no 
 trace of the red will be found. 
 
 Sugar in Vegetables and Fruits. Grind a quarter of a 
 turnip or half an apple through a food cutter. Place the 
 pulp in a piece of cheesecloth and squeeze the juice into a 
 beaker. Taste the juice. Pour about 5 cc. into a test tube 
 and dilute with three or four times its volume of water. 
 Test with Fehling's solution. 
 
 Test beets, carrots, parsnips, etc., for sugar. How does 
 the sugar from the beet differ from that of the apple ? 
 
 Conversion of Starch to Invert Sugar by the Process of 
 Mastication. Grind a few grams of soda or milk crackers in 
 a mortar with enough water to form a thin paste. Transfer 
 to a test tube and test with Fehling's solution. Result ? 
 
 Thoroughly chew about 5 g. of the cracker for about 
 one minute. Test as before. How do you account for the 
 change ? Could the food be chewed too much ? Why ? 
 
 Detection of Adulteration in Maple Sirup. Coloring Matter. 
 Shake 15 cc. of the sirup with 3 cc. of amyl alcohol and 
 1 cc. of H 3 PO 4 (20 per cent). Allow to settle. The amyl- 
 alcohol layer should be a decided brown. Adulterated 
 samples give a straw-to-light-brown color. 
 
 Foam Test. Mix 5 cc. of the sirup and 10 cc. of water in 
 a graduated tube and shake vigorously for half a minute. 
 Allow to stand ten minutes. The foam should not measure 
 less than 3 cc. Adulterated samples give less foam. 
 
EXPERIMENTS WITH C4Lt(O$lt) V ilOl 
 
 Precipitate Test. Mix 5 cc. of tbe /sirup ^ 
 water in a 50-cc. cylinder. Add 2 cc. of lead subacetate 
 solution. Mix well and allow to stand for twenty hours. 
 The precipitate should not measure less than 3 cc. (^Bulletin 
 of Pharmacy, December, WOS.') 
 
 When maple sugar is to be tested, dissolve 15 g. in 
 enough water to make 15 cc. of sirup. 
 
SECTION XIX 
 EXAMINATION OF HEADACHE POWDERS 
 
 A great deal of injury is done each year by the in- 
 discriminate use of headache powders, " cures," " stops," 
 tablets for car sickness, anti-pain tablets and pills, cold 
 " cures," and the like. 
 
 Many of these contain a coal-tar derivative commonly 
 known as acetanilid, or antifebrin. This is the acetyl de- 
 rivative of anilin, and is therefore called phenylacetamid 
 by the chemist. This substance is a dangerous heart de- 
 pressant and should never be used except by the intelligent 
 advice of a physician. 
 
 Another substance frequently used in cheap powders of 
 the above description is phenacetin, known to the chemist 
 as oxyethylacetanilid. If one values his health, he should 
 avoid the common use of such pernicious drugs. 
 
 Detection of Acetanilid in Headache Cures, Cold and Grippe 
 Powders, and like Nostrums. Strobel's Test. Place about 
 0.2 g. of the sample in a 5-in. test tube and add about 
 the same volume of ZnCl 2 . Heat gently, meanwhile hold- 
 ing a wood shaving or splint down the mouth of the tube. 
 White fumes soon appear. Continue heating ; the mixture 
 melts, turns light yellow and finally black. Observe the 
 shaving from time to time. If it is stained yellow, acet- 
 anilid is undoubtedly present. Note the peculiar odor of 
 the fumes. Varnish or shellac the splint and mount it in 
 the notebook with the label from the package. 
 
 102 
 
EXAMINATION OF HEADACHE POWDEKS 103 
 
 Ritsert's Test. Boil 1 g. of the sample in a small beaker 
 for two or three minutes with about 3 cc. strong HC1. Cool 
 and divide into three portions and test in small tubes. 
 
 1. Add carefully 1 to 3 drops of a solution of bleaching 
 powder (CaClO x ), 1 to 200, in such a manner that the two 
 liquids do not mix. A beautiful blue color is seen at the 
 junction of the two liquids 
 
 if acetanilid is present. 
 
 This is known as the in- 
 dophenol reaction, and it re- 
 sponds to anilin compounds 
 generally. 
 
 2. To another portion add 
 a small drop of KMnO 4 . A 
 clear green color is formed 
 if an appreciable amount of 
 acetanilid is present. 
 
 3. Mix the third portion 
 with a 3 per cent chromic acid 
 solution. Acetanilid gives a 
 green color, changing to a 
 dark green in a few minutes, 
 
 and forms a dark blue precipitate on the addition of a drop 
 or two of NaOH solution. 
 
 In the case of powders containing vegetable matter or 
 sugar of milk, both of which will turn brown on heating with 
 HC1, it is advisable to first boil the sample in 5 to 10 cc. of 
 water. Filter, cool the filtrate, and agitate. If acetanilid is 
 present, it will crystallize out and settle. A centrifuge may 
 be used to advantage to separate the crystals from the liquid. 
 This latter which still contains some acetanilid in solution 
 may be discarded and the crystals tested as indicated. 
 
 FIG. 21. Showing method of hold- 
 ing splint for the Strobel test 
 
104 ELEMENTARY APPLIED CHEMISTRY 
 
 The blue color of the bleaching powder solution is prob- 
 ably due to the presence of anilin hydrochlorid. 
 
 Test headache powders for the bromin radical by gently 
 heating with equal parts of MnO 2 and H 2 SO 4 . 
 
 Isonitril Reaction. Heat about a gram of the powder with 
 10 cc. of a 10 per cent NaOH solution. Remove from the 
 flame and cautiously add a few drops of chloroform. Set 
 aside for a few minutes. If acetanilid is present, the greasy, 
 disgusting odor of phenylcarbamine will be apparent. 
 
 This last test is perhaps the best of all, and is especially 
 applicable to a liquid or solid whose color might interfere 
 with the Ritsert test. 
 
 To determine the Per Cent of Acetanilid present. Dis- 
 solve a definite weight of the powder, about 1 g., in hot 
 water. Boil and filter. To the filtrate add bromin water 
 until the yellow color persists. The acetanilid is precipitated 
 as p-bromacetanilid. Dissolve the precipitate in benzol. 
 Filter and evaporate the benzol over a water bath. Dry at a 
 temperature not exceeding 100 F. Weigh the residue. 
 
 Caution. Keep the benzol from all flame, as it is exceed- 
 ingly inflammable. 
 
 Pure acetanilid melts at 113 C. Determine the melting 
 point of your sample. 
 
 If unfamiliar with any of the above tests, work with a 
 known sample. Do not give up until you are familiar with 
 them. You may save the life of some one. 
 
SECTION XX 
 
 TESTS FOR ARSENIC 
 
 Arsenic is one of the most widely distributed elements. 
 Unless care is taken by the manufacturer, it may contami- 
 nate our foods, articles of clothing, wall papers, paint, and 
 the like. In testing any such substance for arsenic it is 
 advisable to partially destroy the organic matter with a 
 mixture of sulfuric and nitric acids. This treatment oxi- 
 dizes the arsenic into arsenic acid, which may be completely 
 removed with boiling water. The method advised is that 
 of Chittenden and Donaldson (Bulletin No. 86, Bureau of 
 Chemistry, United States Department of Agriculture'). 
 
 To successfully perform tests for arsenic, it is absolutely 
 necessary that all of the reagents are themselves free from 
 it. Assure yourself of this first of all. Save time by putting 
 a few scraps of arsenic-free zinc into four different flasks : 
 
 No. 1 containing 10 per cent HC1. 
 
 No. 2 containing 10 per cent H 2 SO 4 . 
 
 No. 3 containing 10 per cent nitro-sulfuric acid. 
 
 No. 4 containing 10 per cent HC1 and a few drops of 
 10 per cent CuCl 2 . 
 
 Over the mouth of each flask place a piece of filter 
 paper, which has been wet with a few drops of concen- 
 trated solution of mercuric chlorid. There should be a 
 brisk evolution of gas. 
 
 If after half an hour the filter paper shows no discolor- 
 ation, the reagents are suitable for use. 
 
 105 
 
100 ELEMENTARY APPLIED CHEMISTRY 
 
 Preparation of the Sample. Wall Paper, Cloth, etc. Place 
 about 25 sq. cm. of the sample cut into small pieces in an 
 evaporating dish. Treat with 1 to 5 cc. of a mixture of con- 
 centrated sulfuric and nitric acids, 30 to 1, both of which 
 have been proved free from arsenic. Add a few drops of 
 
 EIG. 22. Gutzeit apparatus for the detection of arsenic 
 Showing wash bottle with outlet capped with prepared filter paper 
 
 water and allow the action to proceed for five minutes. 
 Heat with a low flame until all of the acid is driven off, 
 or until the residue has granulated and the fumes have 
 nearly disappeared. Break up the charred mass, add a little 
 water, and boil to get rid of the H 2 SO g . Filter through a 
 small filter and wash to about 40 cc. 
 
TESTS FOB ARSENIC 
 
 107 
 
 Preparation of the Sample. Meats, Vegetables, etc. Heat in 
 a porcelain dish about 100 g. of the sample with 23 cc. of 
 HNO 3 , stirring occasionally with a glass rod. When the 
 substance has become a deep yellow or orange color, remove 
 from the heat and add 3 cc. of H 2 SO 4 . Stir the contents of 
 the dish while the nitrous 
 fumes are given off. Care 
 should be taken to pro- 
 tect the hands from these 
 fumes. 
 
 Heat gently and add 
 while hot, drop by drop, 
 8 cc. of HNO 3 , stirring the 
 mass constantly. Heat 
 more strongly until acid 
 fumes come off and a 
 charred mixture remains. 
 Break this up, extract 
 with boiling water, and 
 filter as in the case of 
 wall paper. 
 
 NOTE. Always conduct 
 these preliminary proc- 
 esses under a gas hood 
 or out of doors. 
 
 The Gutzeit Test. Into a clean Erlerimeyer flask of about 
 200 cc. capacity, fitted with a thistle tube and a right- 
 angled delivery tube, place a few pieces of arsenic-free 
 zinc. Slide the zinc gently into the flask to avoid breakage. 
 Pour in the filtrate from the prepared sample and about 
 5 cc. of the tested HC1, containing half a cubic centimeter 
 of a 10 per cent solution of CuCl 2 of known purity. 
 
 FIG. 23. Simple form of Gutzeit 
 apparatus 
 
 Showing the prepared filter paper held 
 over the mouth of the flask 
 
108 ELEMENTARY APPLIED CHEMISTRY 
 
 Allow the escaping gas to pass through a few cubic 
 centimeters of lead acetate solution contained in a small 
 wash bottle or potash bulb, and impinge upon a piece of 
 Swedish filter paper which has been wet with a drop or so 
 of a concentrated solution of mercuric chlorid. 
 
 If after half an hour the paper shows a stain yellow 
 to deep orange, arsenic is present. The color varies with 
 the amount. Very large quantities produce a yellowish- 
 brown stain. 
 
 Write the reaction between free hydrogen and arsenic. 
 What compound causes the yellow color on the filter paper ? 
 If the filter paper remains white, freedom from arsenic is 
 assured. 
 
 Place a little chemically pure 10 per cent HC1 upon per- 
 fectly pure zinc. Result ? Then add a few drops of CuCl 2 
 solution. How do you explain the effect? Why was the 
 copper chlorid solution added to the original sample ? 
 
 Make arsenic tests upon the following : wrapping paper, 
 samples of cloth, candy wrappings, wall paper, etc. Liquids 
 can usually be tested without subjecting them to the pre- 
 vious preparation. 
 
SECTION XXI 
 METHOD FOR TESTING PAINT AND OILS 
 
 If one desires to paint his building with a lead and zinc 
 paint and pays the price, he should get lead and zinc, not 
 sand, lime, and barium sulf ate or barytes. On the other hand, 
 if he pays a sand-and-lime price, he should not expect to get 
 a metallic article. Which kind have you seen used ? 
 
 Extraction of the Oil. Place about 5 g. of the paint in 
 a small flask or beaker and wash with successive portions 
 of warm petroleum ether, or benzine. Heat this in a water 
 bath, away from any flame. Continue the washing until a 
 few drops leave no residue 011 evaporation. 
 
 It is more convenient to conduct the extraction with a 
 Soxhlet apparatus, placing the paint in an extraction shell 
 the weight of which must be previously determined. Dry 
 the undissolved residue at 100 C. and calculate the per 
 cent of the oil. 
 
 To test the Purity of the Oil. Evaporate the ether extract 
 from the previous experiment. Warm 2 cc. of the oil so 
 obtained in a test tube and add an equal volume of glacial 
 acetic acid. Cool in running water and add one drop of con- 
 centrated H 2 SO 4 . Pure linseed oil turns sea-green, the color 
 deepening on standing. A fugitive violet color indicates 
 rosin oil. 
 
 Heat a little of the oil in a test tube to about 100 C. 
 Cool and rub on the back of the hand. If present, fish oil 
 will be detected by the characteristic fishy odor. 
 
 109 
 
110 ELEMENTARY APPLIED CHEMISTRY 
 
 To test the Body of the Paint. 1. Boil a portion of the 
 residue with strong acetic acid. A residue indicates BaSO 4 
 or sand (SiO 2 ), or both. Save the nitrate. 
 
 2. To a second portion add an equal volume of Na 2 CO g , 
 then mix and fuse with a blowpipe on charcoal. If lead is 
 present, a small metallic globule will fuse out. Lead in 
 paint is usually present in the form of basic lead carbonate, 
 2PbCO 3 -Pb(OH) 2 . 
 
 3. Moisten a third portion with a solution of Co (NO 3 ) 2 . 
 Heat strongly as before. A green color indicates zinc. 
 Probably ZnO is in the original paint. 
 
 4. To the nitrate from 1 add an excess of NH/HI 
 and then ammonium oxalate. If lime is present, a white 
 precipitate of oxalate of lime is formed. 
 
 Suggest a method for determining how much of each 
 ingredient is present. 
 
 Test for the Purity of Olive Oil. Shake equal volumes 
 (5 cc.) of the oil and HNO 3 . Pure oil should turn from 
 pale to dark green in a few minutes. If it changes to brown, 
 red, or orange, the addition of a foreign oil is indicated. 
 
 Heat for five minutes in a water bath at 100 C. It should 
 become pale yellow to orange yellow. On standing it will, 
 if pure, become a yellow solid. (LeacKs test*) 
 
 Free Fatty Acids in Olive Oil. Weigh exactly 20 g. of 
 the sample into a counterpoised Erlenmeyer flask and add 
 50 cc. of neutral alcohol. Mix thoroughly and heat the 
 contents to 60 C. 
 
 Titrate with tenth-normal sodium hydrate, using phe- 
 nolphthalein as an indicator. Shake the mixture often dur- 
 ing the titration. The number of cubic centimeters of the 
 alkali used" to neutralize the acid in 1 g. of the oil is called 
 the Acid Number. 
 
METHOD FOE TESTING PAINT AND OILS 111 
 
 Each cubic centimeter of tenth-normal sodium hydrate 
 equals 0.0282 g. of oleic acid. Tabulate the results as Acid 
 Number and also as Per Cent of Oleic Acid. 
 
 The fresher and better grades of olive oils contain the 
 least amount of free fatty acid. 
 
 Neutral Alcohol. Titrate any convenient volume of 95 per cent alco- 
 hol with tenth-normal alkali, using phenolphthalein as an indicator. 
 
 BACH'S TABLE FOR OIL REACTIONS 
 
 
 
 AFTER HEATING 
 
 CONSISTENCY 
 
 KIND OF OIL 
 
 AFTER AGITATION 
 
 WITH HNO 3 
 
 FOR FIVE MINUTES 
 ON WATER BATH 
 
 AFTER STANDING 
 TWELVE TO 
 
 
 
 
 EIGHTEEN HOURS 
 
 Olive .... 
 
 Pale green 
 
 Orange to yellow 
 
 Solid 
 
 Peanut . . . 
 
 Pale rose 
 
 Brownish yellow 
 
 Solid 
 
 Rape .... 
 
 Pale rose 
 
 Orange yellow 
 
 Solid 
 
 Sesame . . . 
 
 White 
 
 Brownish yellow 
 
 Liquid 
 
 Sunflower . . 
 
 Dirty white 
 
 Reddish yellow 
 
 Buttery 
 
 Cottonseed . . 
 
 Yellowish brown 
 
 Reddish brown 
 
 Buttery 
 
 Castor .... 
 
 Pale rose 
 
 Golden yellow 
 
 Buttery 
 
 Detection of Cottonseed Oil in Olive Oil. Take any con- 
 venient volume of CS in which 1 per cent of sulfur has 
 been previously dissolved, and add an equal volume of 
 amyl alcohol (fusel oil). 
 
 To 5 cc. of the sample add an equal volume of the re- 
 agent. Stop the test tube loosely with cotton and heat for 
 fifteen minutes in a bath of saturated boiling brine. 
 
 If cottonseed oil is present, a deep red to orange color is 
 developed. Pure olive oil gives little or no color under this 
 treatment. (Halphen test.) 
 
 This test can also be used for the detection of cottonseed 
 oil in lard. The fat from animals fed on cottonseed meal is 
 said to give a faint reaction. 
 
112 ELEMENTARY APPLIED CHEMISTRY 
 
 If the olive oil containing cottonseed oil has been pre- 
 viously heated, the reaction is much less delicate. 
 
 Kapok oil, from the seeds of the Eriodendron anfractuo- 
 sumj and baobab oil give the same reaction. A distinction 
 can, however, be made, since the two last oils react without 
 heating, while cottonseed oil must be heated. 
 
 To distinguish Renovated from Creamery or Dairy Butter. 
 Melt two or three grams of butter in an iron spoon. Pure 
 butter melts quietly with the production of much foam. 
 Renovated butter and oleomargarine bump and sputter like 
 hot grease and produce no foam to speak of. 
 
 Waterhouse Test for Oleomargarine. Thoroughly shake 
 50 cc. of sweet milk and heat nearly to boiling. Add from 
 2 to 5 g. of the sample and stir with a small wooden stick 
 flattened at one end until the fat is entirely melted. 
 
 Place the beaker in a dish of ice water and continue 
 stirring until the fat solidifies. 
 
 If the sample is oleomargarine, the fat can be collected 
 into a lump. Butter fat cannot be so collected, but is more 
 or less emulsified with the milk. 
 
 If the sample is renovated butter, it will tend to collect 
 as a film on the surface of the milk when the stirring is 
 stopped. It does not clot or gather like oleomargarine, but 
 usually adheres to the wooden rod. 
 
SECTION XXII 
 DETEEMINATION OF FOOD VALUES 
 
 Total Nitrogen and Proteids of Cereal Products. Gunning's 
 Method. This method consists in decomposing the organic 
 matter by prolonged digestion with sulfuric acid and potas- 
 sium sulfate. The carbon is driven off as CO 2 and the 
 hydrogen as water. The nitrogen is converted into am- 
 monium sulfate from which the free ammonia is liberated 
 by means of an alkali and distilled into a known volume 
 of N/10 acid, and the amount calculated by titrating the 
 acid remaining. 
 
 It should be observed that foods in their natural state 
 seldom if ever contain nitrates. Should this radical be 
 present in appreciable amounts, the Gunning method must 
 be modified. 
 
 Prove the absence of nitrates by extracting about 5 g. 
 of the sample with water. Filter and test the filtrate by 
 mixing with a solution of ferrous sulfate. Add concentrated 
 sulfuric acid so as to form a layer below the mixed solution. 
 In the presence of nitrates a dark brown ring forms at the 
 juncture of the two liquids. 
 
 Prove the reliability of this reaction by working with a 
 solution known to contain a nitrate. 
 
 In the absence of nitrates proceed with the Gunning 
 method as follows : 
 
 Weigh exactly 0.5 g. of the finely powdered sample 
 bread, macaroni, breakfast food, etc. and transfer to a 
 
 113 
 
114 ELEMENTARY APPLIED CHEMISTRY 
 
 clean, dry Kjeldahl flask of about 250 cc. volume. Add 
 10 g. of K 2 8O 4 and from 15 to 25 cc. concentrated H 2 SO 4 . 
 Incline the flask at an angle of about 75 over a small bare 
 flame and heat gently until all foaming stops. 
 
 The mixture is now of a dark brown color. Slip a piece 
 of wire gauze under the flask and slightly increase the heat 
 
 until the gauze is cherry red 
 where it comes in contact 
 with the bottom of the flask- 
 Place a funnel in the 
 neck of the flask to act as a 
 reflux condenser. Continue 
 heating until the contents 
 are colorless or of a pale 
 straw color. This usually 
 takes from thirty minutes 
 to two hours. Conduct the 
 heating in a gas hood. 
 
 Allow the flask to cool. 
 Transfer the liquid into a 
 boiling flask of about 500 cc. 
 capacity, rinsing carefully 
 with 200 cc. of water. 
 
 Add sufficient saturated 
 solution of NaOH to make 
 the contents strongly alkaline, using phenolphthaleiii as 
 an indicator. 
 
 Place two or three pieces of zinc in the boiling flask to 
 prevent bumping, and distil off at least 150 cc., using a ver- 
 tical condenser whose outlet dips below the surface of ex- 
 actly 50. cc. of N/10 H 2 SO 4 contained in the receiving flask. 
 (See apparatus for the detection of sulfurous acid.) 
 
 FIG. 24. Kjeldahl flask arranged for 
 the determination of nitrogen 
 
DETERMINATION OF FOOD VALUES 115 
 
 It is of the utmost importance to know the exact volume 
 of standard acid in the receiving flask. Measure with an 
 accurate pipette. 
 
 When all the ammonia has been distilled and absorbed, 
 titrate the contents of the receiving flask with N/10 NaOH, 
 using cochineal as an indicator. 
 
 The difference between the original volume of the stand- 
 ard acid and the volume of N/10 NaOH required to titrate 
 it represents the number of cubic centimeters of N/10 H 2 SO 4 
 
 FIG. 25. Digesting shelf for making simultaneous nitrogen determinations 
 
 neutralized by the liberated ammonia. Every cubic centi- 
 meter of N/10 sulfuric acid represents .0014 g. of nitrogen. 
 The proteids are calculated from the total nitrogen by 
 multiplying by the factor 6.25. This factor is the one 
 generally adopted in determinations of this kind. 
 
 EXAMPLE. Weight of cereal 0.5 g. 
 Volume of N/10 H 2 SO 4 = 50 cc. 
 
 Required 44 cc. of N/10 NaOH to titrate the excess acid. 
 Therefore 6 cc. of N/10 II 2 S() 4 were neutralized by the liberated 
 ammonia. 
 
 1 cc. of N/10 H 2 SO 4 = .0014 g. of nitrogen. 
 6 cc. of N/10 H 2 SO 4 = 6 X .0014, or .0084 g. of nitrogen. 
 6.25 x .0084 = .0525 g. of proteid. 
 
 .0525/.5 = 10.5 per cent of proteid. 
 
 In such an analysis as the preceding one it is customary 
 to state that the Protein = 6.25 x N. 
 
116 ELEMENTARY APPLIED CHEMISTKY 
 
 Fat of Cereal Products, known as " Ether Extract. " 
 Weigh from 2 to 3 g. of the sample into a tared extraction 
 shell (Schleicher and Schull). Dry thoroughly at 212. 
 
 Place the shell in a Soxhlet or Wiley Extractor and 
 extract with water-free ether. Dry the shell and residue to 
 
 constant weight and by differ- 
 ence calculate the ether-soluble 
 matter. 
 
 A thorough extraction re- 
 quires several hours. Great 
 caution must be exercised in 
 heating the extracting appara- 
 tus lest the ether take fire. 
 Use a large water bath and a 
 small flame, or, still better, an 
 electric stove. 
 
 Water or Moisture in Cereal 
 Products. Weigh from 2 to 5 g. 
 of the sample into a tared watch 
 glass. Spread it evenly over the 
 bottom, forming as thin a layer 
 as possible. Dry at 100 C., cool, 
 and reweigh. Calculate the per 
 cent of water by difference. 
 
 Ash or Mineral Content of 
 Cereal Products. Transfer the 
 dried residue from the water determination to a tared porce- 
 lain crucible, taking care that none of the sample is lost. 
 Burn to a white ash at the lowest temperature possible. If 
 too much heat is employed, the ash will fuse to the bottom 
 of the crucible. Cool in a desiccator, reweigh, and calculate 
 the per cent. 
 
 FIG. 26. Soxhlet extraction ap- 
 paratus properly set up 
 
DETERMINATION OF FOOD VALUES 117 
 
 Carbohydrates in Cereal Products. The carbohydrates are 
 often expressed by adding the per cent of water, ash, pro- 
 teids, and fat, and subtracting the sum from 100. 
 
 Calculation of Fuel Value. This value may be approxi- 
 mately determined by means of the Rubner factors, which 
 give for each pound of protein or carbohydrate 1860 calories, 
 and for each pound of fat 4220 calories. 
 
 EXAMPLE. Suppose the analysis of a certain cereal product shows : 
 protein, 13.4 per cent ; carbohydrates, 74.1 per cent ; fat, 0.9 per cent. 
 Then 1860 x (.134 + .741) = 1627.50 calories 
 
 4220 x .009 = 37.98 calories 
 Total 1665.48 
 
SECTION XXIII 
 TESTING UKINE 1 
 
 Determine Reaction. Normal, slightly acid ; after a full 
 meal may be alkaline. 
 
 Determine Odor. Normal, peculiar, aromatic. 
 
 Determine Color. Normal, pale straw to reddish yellow. 
 May be very pale by nervousness or excessive drinking. 
 
 Determine Specific Gravity. Normal, 1.015 to 1.025 at 
 60 F. 
 
 Determine Total Solids. Normal, 3.4 per cent to 5.8 per 
 cent. Total solids equal (specific gravity 1) multiplied 
 by 2.33. This is equivalent to the number of grams per 
 cubic centimeter. 
 
 To detect Albumen and Phosphates. First Method. Fill a 
 test tube half full of clear urine. Boil the upper portion 
 of the liquid. A turbidity indicates 'albumen or PO 4 , or 
 both. Add a drop of acetic or nitric acid ; the phosphates 
 dissolve, the albumen does not. 
 
 Second Method. Place about a cubic centimeter of con- 
 centrated HNO 8 in a test tube, and by means of a pipette 
 allow two or three cubic centimeters of the urine to rest 
 upon its surface. 
 
 If albumen is present, a white zone or flocculent pre- 
 cipitate forms at the ring of contact of the two liquids. 
 The extent of turbidity indicates roughly the amount of 
 albumen present. 
 
 1 For more complete analysis see Merck's Manual for 1911. 
 118 
 
TESTING URINE 119 
 
 A green turbidity indicates biliary pigments. Reddish 
 brown indicates blood. 
 
 Urates or Uric Acid. Murexide Test. Evaporate a few 
 drops of urine to dryness on a watch glass. Add a drop or 
 two of HNO 3 and again cautiously evaporate. Then add 
 an equal volume of NH 4 OH. A purple color indicates 
 urates, uric acid, or both. 
 
 Invert Sugar. Fehling's Test. Boil 5 cc. of Fehling's 
 solution, and if the color does not change, add an equal 
 volume (not more) of urine, and boil. In the presence of 
 reducirig sugars the characteristic red-to-yellow precipitate 
 forms. (See tests for glucose.) Use this test only when 
 uric acid is absent. 
 
 Haines's Test. Reagents: CuSO 4 , 2g.; glycerin, 20 g.; 
 KOH, 9 g. ; water, 175g. Boil 4 cc. of the solution and 
 add 6 to 10 drops (not more) of the urine and boil again. 
 In the presence of reducing sugars the yellow-to-red pre- 
 cipitate forms. 
 
 Detection of Sugar in the Presence of Urates or of Uric 
 Acid. Heat 1 g. of phenyldrazine hydrochlorate, 2 g. of 
 sodium acetate, and 25 cc. of urine, and if the salts do not 
 completely dissolve, add a little water, and place in boil- 
 ing water. 
 
 Remove after twenty minutes to cold water. If sugar is 
 present, characteristic crystals of phenylglucosazone form. 
 
 Chlorids. Add a few drops of nitric acid to the urine 
 to prevent the precipitation of the phosphates, and gradu- 
 ally add a few drops of AgNO 3 . A white precipitate solu- 
 ble in ammonia indicates chlorids. If present in small 
 quantity, a milky color only will be seen. 
 
 Sulfates. Use BaCl 2 instead of the silver nitrate. If 
 present, the insoluble precipitate of BaSO 4 will be seen. 
 
SECTION XXIV 
 
 SELECTED EXERCISES 
 
 An Experiment with the Albumen of Meat. The most 
 important solid constituent of the body of an animal is 
 albumen. Place about 20 g. of lean beef finely minced in a 
 beaker of cold water and gradually heat to about 130 F. 
 Remove, filter the liquid, and test as follows : 
 
 To a portion add HNO g . A white precipitate or a decided 
 milkiness indicates albumen. 
 
 To another portion add a few drops of iodin. A yellow 
 or port-wine color indicates the presence of glycogeii or 
 animal starch. 
 
 Repeat the above experiment by placing the same weight 
 of beef in actively boiling water. Leave for a minute and 
 test as before. How do you account for the difference ? 
 What does this show concerning the cooking of meats ? 
 
 Examination of Common Salt. Moisture. Purchase as 
 many different brands of table salt as possible ; also several 
 samples of " coarse-fine " and rock salt. 
 
 Place exactly 5 g. of the sample in a small tared Erlen- 
 meyer flask and heat to a temperature not exceeding 150 C. 
 for three hours 011 a sand bath. Remove from the bath, in- 
 sert a funnel in the mouth of the flask, and allow the contents 
 to cool. The introduction of the funnel renders the use of a 
 desiccator unnecessary for this determination. Reweigh, and 
 from the loss of weight calculate the per cent of moisture. 
 Reserve the residue for the determination of MgCl 2 . 
 
 120 
 
SELECTED EXERCISES 121 
 
 Insoluble Matter. Dissolve 5 g. of the sample in 100 cc. 
 of water, heating gently if necessary. Filter the solution 
 through a balanced filter paper, washing the residue with 
 warm water until the filtrate shows no precipitate with 
 AgNO 3 solution. Dry and weigh the contents of the filter 
 paper and calculate the per cent of insoluble matter. 
 
 Chlorin. Dissolve 5 g. of the undried sample in a little 
 water and make up the solution to exactly 500 cc. in a 
 measuring flask. Mix thoroughly and withdraw 10 cc. by 
 means of a pipette. Place in a clean beaker and add an equal 
 volume of distilled water. Titrate with N/10 AgNO 3 , using 
 neutral potassium chromate as an indicator (see p. 30). A 
 liter of N/10 silver nitrate contains 17g. of the pure 
 crystallized salt. 
 
 Deduct 0.1 cc. of the silver solution added, as this amount 
 is required to produce the permanent red tinge. Every 
 cubic centimeter of the N/10 AgNO 3 is equivalent to 
 0.00355 g. of chlorin. 
 
 The 10 cc. of the titrated salt solution contained, theo- 
 retically, how many grams of chlorin ? How many grams 
 did you find ? What was the per cent of chlorin ? 
 
 Suggestion. How many grams of salt did you dissolve ? 
 To what volume did you dilute it ? How many grams of 
 salt in 10 cc. of this solution ? 
 
 Calcium Sulfate. First Method. Dissolve 5 g. of the sample 
 in 20 cc. of water to which 2 cc. of HC1 have been added. 
 Boil gently, being careful to lose none of the solution during 
 the process. In the case of rock salt it may be necessary to 
 continue the treatment for some time in order to dissolve 
 all of the CaSO 4 . 
 
 Neutralize the solution with ammonia and precipitate 
 the calcium with (NH 4 ) 2 C 2 O 4 . Allow it to stand overnight 
 
122 ELEMENTARY APPLIED CHEMISTRY 
 
 and filter the solution through a fine, ashless filter paper. 
 Wash the residue carefully, dry, and ignite it in a weighed 
 crucible until the oxalate is converted into CaO. This will 
 require about twenty minutes at a white heat. Cool and 
 weigh as CaO. One part of CaO is equivalent to 2.4271 
 parts of CaSO 4 . Calculate the per cent of CaSO 8 in the 
 original sample. 
 
 Second Method. Dissolve 10 g. of salt in warm water 
 containing 1 per cent of HC1. Dilute to a liter and draw 
 out 250 cc. (2.5 g. of salt). Heat this portion to boiling, 
 add 1 cc. of HC1, and immediately pour in about 20 cc. of 
 boiling 10 per cent BaCl 2 . Do not add the barium chlorid 
 solution drop by drop, but introduce it all at once. The 
 precipitate should settle in half an hour. Decant the clear 
 portion through an ashless filter paper. Pour 100 cc. of 
 boiling water on the precipitate, agitate, and allow to settle, 
 which it should do in about four minutes. Decant again 
 and repeat the operation until the liquid ceases to give 
 an acid reaction. Finally wash the precipitate on the filter. 
 Dry, ignite at a low heat, and weigh the BaSO 4 . From this 
 calculate the per cent of CaSO 4 in the sample. 
 
 Magnesium Chlorid. Into the flask containing the dried 
 residue from the moisture determination place 25 cc. of abso- 
 lute alcohol. Cork the flask and gently shake the contents 
 from time to time for ten minutes. Filter and evaporate 
 the alcohol, which contains nothing but MgCl 2 . Dissolve the 
 residue in water and titrate with N/10 AgNO g . 
 
 From the chlorin found calculate the per cent of MgCl 2 
 in the sample. 
 
WORKING TABLE OF THE ELEMENTS 123 
 
 SYMBOLS, ATOMIC WEIGHTS, AND VALENCE OF THE 
 MORE IMPORTANT ELEMENTS 
 
 ELEMENT 
 
 SYMBOL 
 
 ATOMIC WEIGHT 
 
 VALENCE 
 
 Aluminium .... 
 
 Al 
 
 27.1 
 
 3 
 
 Antimony 
 
 Sb 
 
 120.2 
 
 3, 5 
 
 Arsenic 
 
 As 
 
 75 
 
 3, 5 
 
 Barium .... 
 
 Ba 
 
 137.3 
 
 2 
 
 Bismuth 
 
 Bi 
 
 208 
 
 3, 5 
 
 Boron . 
 
 B 
 
 11 
 
 3 
 
 Bromin . . . 
 
 Br 
 
 79.9 
 
 1 
 
 Cadmium 
 
 Cd 
 
 112.4 
 
 2 
 
 Calcium 
 Carbon .... 
 
 Ca 
 C 
 
 40 
 12 
 
 2 
 4 
 
 Chlorin 
 
 Cl 
 
 35.5 
 
 1 
 
 Chromium 
 Cobalt . 
 
 Cr 
 
 Co 
 
 52.1 
 58.9 
 
 2,3,6 
 2 
 
 Copper 
 Fluorin ...... 
 Gold . ... 
 
 Cu 
 F 
 Au 
 
 63.6 
 19 
 197.2 
 
 1,2 
 1 
 1, 3 
 
 Hydrogen 
 
 H 
 
 1 
 
 1 
 
 lodin 
 
 I 
 
 126.9 
 
 1 
 
 Iron 
 
 Fe 
 
 55.8 
 
 2, 3 
 
 Lead 
 
 Pb 
 
 207.1 
 
 2, 4 
 
 Magnesium 
 Manganese 
 
 Mg 
 Mn 
 
 24.3 
 54.9 
 
 2 
 2, 4 
 
 Mercury 
 Nickel 
 
 Hg 
 
 Ni 
 
 200 
 58.6 
 
 1,2 
 
 2 
 
 Nitrogen ...... 
 Oxv"en 
 
 N 
 
 o 
 
 14 
 
 16 
 
 3,5 
 
 2 
 
 Phosphorus 
 
 p 
 
 31 
 
 3, 5 
 
 Platinum .... 
 
 Pt 
 
 195 
 
 4 
 
 Potassium 
 
 K 
 
 39.1 
 
 1 
 
 Silicon 
 
 Si 
 
 28.3 
 
 4 
 
 Silver 
 
 As- 
 
 107.8 
 
 1 
 
 Sodium ...... 
 Strontium 
 
 Na 
 Sr 
 
 23 
 
 87 6 
 
 1 
 
 2 
 
 Sulfur 
 
 S 
 
 32 
 
 2, 4, 6 
 
 Tin. . 
 Zinc 
 
 Sn 
 Zn 
 
 119 
 65.3 
 
 2,4 
 
 2 
 
INDEX 
 
 Acetanilid, detection of, 102; de- 
 termination of, 104 
 Acetic acid, per cent of, 22 
 Acidity of milk, 20 
 Acids and alkalis, 5 
 Adulteration of milk, 45 
 Albumen, test for, 118 
 Alcohol, ethyl, 55; methyl, 60; 
 
 per cent of, 58 ; preparation of, 
 
 56 ; tables, 66 
 Alkali, free and combined in soap, 
 
 25 
 
 Alkaline carbonates in soap, 26 
 Alum; tests for, 39 
 Ammonia in baking powder, 39; 
 
 in water, detection of, 31 
 Ammonium molybdate solution, 
 
 33 
 
 Annatto, detection of, 45 
 Arsenic, tests for, 107 
 Artificial colors in milk, 45 
 Ash, of cereal products, 116; of 
 
 vinegar, 22 
 Atomic weights, table of, 123 
 
 Bach's table for oil, 111 
 Baking-powder analysis, 35 
 Baking soda, test for purity, 20; 
 
 in milk, 47 
 
 Barium sulfate in paint, 110 
 Bases in baking powder, 39 
 Borates in soap, 27 
 Boric acid, detection of, 91 
 Boron in milk, 47 
 
 Butter, boron compounds in, 92; 
 coal-tar dye in, 77 ; renovated, to 
 distinguish, 112 
 
 Calcium carbonate in soils, 9 
 Calcium sucrate in cream, 48 
 Calcium sulfate in salt, 121 
 Cane sugar, inversion of, 98 
 Caramel, detection of, 79 
 Carbohydrates in cereal products, 
 
 117 
 
 Carbon dioxid in baking powders, 35 
 Cheese, fat in, 52 
 Chlorids in plants, 15 
 Chlorin, in salt, 121 ; in water, 
 
 tests for, 30 
 
 Chlorophyl, extraction of, 13 
 Cider vinegar, to distinguish, 23 
 Citric acid, per cent of, 19 
 Cloth, arsenic in, 106 
 Coal-tar dye, detection of, 76 
 Cochineal, 80 
 Cocoa, purity of, 24 
 Condensed milk, fat in, 53 ; times 
 
 condensed, 53 
 
 Cottonseed oil in olive oil, 111 
 Cream, determination of fat in, 52 
 
 Dirt in milk, 44 
 Distillation experiments, 54 
 
 Equivalents of N/10 NaOH, 19 
 Erythrosin as an indicator, 34 
 Essential oils, extraction of, 44 
 
 .125 
 
126 ELEMENTARY APPLIED CHEMISTRY 
 
 Fabrics, wool and cotton in, 7 
 Fat, in cereal products, 116; in 
 
 milk by the Babcock test, 41 
 Fatty acids in olive oil, 110 
 Fehling's solution, 98 
 Filtration experiments, 1 
 Flame tests, 10 
 Food preservatives, 90 
 Food values, determination of, 113 
 Formaldehyde in milk, 46 
 Fuel values, calories, 117 
 
 Gelatin in milk, cream, etc., 48 
 Glucose, preparation of, 97; tests 
 
 for, 98 
 Gunning's method for nitrogen, 
 
 115 
 Gunpowder, analysis of, 2 
 
 Hardness of water, 34 
 Headache powders, analysis of, 102 
 Honey, glucose in, 99 
 Hydrochloric acid in soils, 10 
 
 Ice cream, fat in, 52 ; gelatin in, 
 48 ; starch in, 52 
 
 Ink eradicator, 88 
 
 Invert sugar, in honey, 99 ; in veg- 
 etables, 100 
 
 Iron in plants, 15 
 
 Iron oxid in soils, 9 
 
 Lactic acid, per cent of, 20 
 
 Lead in paint, 110 
 
 Lemon extract, coal-tar dye in, 78 ; 
 per cent of oil in, 65; prepara- 
 tion of, 64 
 
 Lime in paint, 110 
 
 Litmus, use of, 5 
 
 Magnesium in soils, 11 ; chlorid in 
 salt, 122 
 
 Maple sirup, tests for purity, 100 
 
 Martin's reagent, 78 
 
 Metallic compounds in water, 34 
 
 Methyl orange as an indicator, 34 
 
 Milk analysis, 41 
 
 Mineral acids in vinegar, 23 
 
 Nessler's reagent, 31 
 Nitrate of mercury, acid, 49 
 Nitrates and nitrites, detection of, 
 
 in water, 32 
 Nitric aeid in soils, 11 
 Nitrogen, determination of, 115 ; 
 
 in plants, 13 
 
 Oil, extraction of, from paint, 109 ; 
 
 olive, examination of, 110 
 Oleomargarine, to detect, 112 
 Oxalic acid N/10, 17 
 Oxygen absorbed in water, 33 
 Oysters, water in, 4 
 
 Paint analysis, 109 
 Phenolphthalein as an indicator, 17 
 Phosphates in water, 32 
 Phosphoric acid, in plants, 15; in 
 
 soils, 11 
 
 Plant analysis, 13 
 Potash, in plants, 14 ; in soils, 10 
 Potassium sulfo-cyanide test, 10 
 Preservatives in milk, 46 
 Proteins, determination of, 115 
 Pumice stone in tooth powder, 95 
 
 Radicals in baking powder, 38 
 Raffia dyeing, 81 
 
 Richmond scale for total solids in 
 milk, 44 
 
 Saccharin, detection of, 94 
 Salicylic acid, detection of, 93 
 Salt analysis, 120 
 
INDEX 
 
 127 
 
 Sand in soils, 11 
 
 Sediment in water, 28 
 
 Silica in plants, 15 
 
 Skimmed milk, identification of, 51 
 
 Soap, analysis of, 25 ; insoluble mat- 
 ter in, 25 
 
 Soda, in plants, 14 ; in soils, 10 
 
 Sodium bicarbonate in milk, 47 
 
 Sodium hydrate N/10, 17 
 
 Soil analysis, 9 
 
 Soils, acidity and alkalinity of, 24 
 
 Specific gravity of milk, 43 
 
 Stains, chemistry of, 88 
 
 Standard solutions, 16 ; exercises 
 with, 19 
 
 Starch, conversion to invert sugar, 
 97 ; effect of mastication on, 
 100 ; test for, 14 
 
 Sugar in urine, detection of, 119 
 
 Sulfates, in plants, 15 ; in soils, 10 
 
 Sulf uric acid, in soils, 10 ; in vine- 
 gar, 23 
 
 Sulfurous acid, detection of, 90; 
 determination of, 91 
 
 Tartrates, test for, 38 
 Tea, soluble matter in, 3 
 
 Theine, extraction of, 4 
 
 Titration, 16 
 
 Tonsillitis Specific, 1 
 
 Tooth powder, examination of, 95 
 
 Total solids, in milk, 43 ; in water, 
 
 29 
 
 Turmeric, tests for, 80 
 Turmeric tincture, preparation of, 
 
 47 
 
 Urine analysis, 118 
 
 Vanilla extract, preparation of, 62 ; 
 
 tests for, 63 
 Vegetable colors, identification of, 
 
 79 
 
 Vinegar analysis, 21 
 Vinegar eels, 21 
 
 Wall paper, arsenic in, -106 
 
 Water, analysis of, 28; in cereal 
 products, 116 ; in milk, detec- 
 tion of, 51 
 
 Waterhouse test for butter, 112 
 
 Wool in fabrics, 7 
 
 Zinc in paint, detection of, 110 
 
ANNOUNCEMENTS 
 
PURE FOODS 
 
 THEIR ADULTERATION, NUTRITIVE VALUE, 
 AND COST 
 
 By JOHN C. OLSEN, Professor of Analytical Chemistry, Polytechnic Institute of 
 Brooklyn, N.Y., Editor of Van Nostrum? s Ckcmical Annual, etc. 
 
 nmo, cloth, 210 pages, illustrated, 80 cents 
 
 " Pure Foods : their Adulteration, Nutritive Value, and Cost" 
 aims to present, in language easily understood, the results of the 
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 The text includes the chemical composition of each class of 
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 The nutritive value of foods being given, it is shown how 
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 There is a statement of legal requirements for pure foods, 
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 This volume is admirably adapted for use in domestic science 
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AN ELEMENTARY STUDY OF 
 CHEMISTRY 
 
 By WILLIAM McPHERSON, Professor of Chemistry in Ohio State University, 
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