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REPORT

OF THE

COMMITTEE ON EDITING TENTATIVE
AND OFFICIAL

Methods of Analysis

THE ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS

WILLIAMS & WILKINS COMPANY

BALTIMORE. U. S. A.

1916

Copyright, 1916

BY

The Association of Official Agricultural Chemist?-

COMPOSED AND PRINTED AT THV

WAVERLY PRESS

Bt the Williams & Wilkins Covputr

Baltimore, Md., U. S. A.

CONTENTS

I. Fertilizers 1

II. Soils . 17

III. Plant Constituents 29

IV. Waters 35

V. Tanning Materials 53

VI. Leathers 59

VII. Insecticides and Fungicides 63

VIII. Foods and Feeding Stuffs 79

IX. Saccharine Products 121

X. Food Preservatives 141

XI. Coloring Matters in Foods 155

XII. Metals in Foods 171

XIII. Fruits and Fruit Products 177

XIV. Canned Vegetables 185

XV. Cereal Foods 187

XVI. Wines ,133

XVII. Distilled Liquors 243

XVIII. Beers 249

XIX. Vinegars 253

XX. Flavoring Extracts 259

XXI. Meat and Meat Products 271

XXII. Dairy Products 287

XXIII. Fats and Oils 299

XXIV. Spices and Other CondimeDts 317

XXV. Cacao Products 327

XXVI. Coffees 331

XXVII. Tea 335

XXVIII. Baking Powders and Their Ingredients 339

XXIX. Drugs 351

Index 367

ILLUSTRATIONS

Figure 1. Combustion tube for the determination of total nitrogen 9

Figure 2. Parr's apparatus for the determination of carbon dioxid 18

Figure 3. Modified Marr apparatus for determining carbon dioxid 19

Figure 4. Metal extractor used for extracting tanning materials 56

Figure 5. Apparatus for distillation of arsenic chlorid 64

Figure 6. Apparatus for detection of formic acid 153

Figure 7. Apparatus for the determination of arsenic 172

Figure 8. Apparatus for the determination of volatile acids 239

Figure 9. Apparatus for the Folin ammonia determination 275

Figure 10. Van Slyke apparatus for the determination of amino nitrogen 282

Figure 11. Details of the deaminizing bulb and connection 283

Figure 12. Apparatus for the melting point determination 303

Figure 13. Apparatus for the determination of the Polenske number 309

Figure 14. Knorr's apparatus for the determination of carbon dioxid 339

Figure 15. Heidenhain's apparatus for the determination of carbon dioxid 341

TABLES

Table 1

Table 2.

Table 3,

Table 4.

Table 5.

Table 6.

Table 7.

Table 8.

Table 9.

Table 10.

Table 11.
Table 12.

Table 13.
Table 14.
Table 15.
Table 16.

Table 17.

Table 18.

Table 19.
Table 20.

Munson and Walker's Table. For calculating dextrose, invert sugar
alone, invert sugar in the presence of sucrose (0.4 gram and 2 grams
total sugar), lactose (two forms), and maltose (anhydrous and

crystallized) 88

Herzfeld's Table. For the determination of invert sugar in mate-
rials containing 1.5%, or less, of invert sugar and 98.5%, or more,

of sucrose 99

Meissl and Hiller's factors for determinations in materials in which,
of the total sugars present, 1.5%, or more, is invert sugar, and 98.5%,

or less, is sucrose 100

Meissl's Table. For the determination of invert sugar alone 101

For the determination of maltose 103

For the determination of lactose 105

Allihn's Table. For the determination of dextrose 107

Krober's Table. For determining pentoses and pentosans 112

For correction of the readings of the Brix spindle when made at other

than the standard temperature, 17.5°C 123

17 5°C
For the comparison of specific gravities at 17'0 ', degrees Brix and

degrees Baume 124

Densities of solutions of cane sugar at 20°C 125

Geerlig's Table. For dry substance in sugar-house products by the

Abbe ref ractometer, at 28°C 127

Corrections for temperature 128

Color reactions produced on dyed fibers by various reagents 161

Behavior of certain natural coloring matters with common reagents.. 166
Alcohol Table. For calculating the percentages of alcohol in mix-
tures of ethyl alcohol and water from their specific gravities 194

Alcohol Table. For calculating the percentages of alcohol in mix-
tures of ethyl alcohol and water from their Zeiss immersion refrac-

tometer readings at 17.5°-25°C 208

Scale readings of the Zeiss immersion refractometer at 20°C, corre-
sponding to each per cent by weight of methyl and ethyl alcohols. . 247
Volumes of milk corresponding to a lactose double normal weight. . . 288
Butyro-refractometer readings and indices of refraction 301

RECOMMENDATIONS FOR OFFICIAL AND TENTATIVE
METHODS OF ANALYSIS, AS PRESENTED AT
THE ANNUAL MEETING OF THE ASSO-
CIATION OF OFFICIAL AGRICUL-
TURAL CHEMISTS, NOVEMBER
16 AND 17, 1915.

I. FERTILIZERS.

GENERAL METHODS.

1 MECHANICAL ANALYSIS OF BONE AND TANKAGE.-TENTATIVE.
Transfer 100 grams of the original material to a sieve having circular openings

1/50 inch (0.5 mm.) in diameter. Sift, breaking the lumps by means of a soft rubber
pestle if the material has a tendency to cake. Weigh the coarse portion remaining
on the sieve. Determine the fine portion by difference.

2 PREPARATION OF SAMPLE.— OFFICIAL.

Reduce the gross sample by quartering to an amount sufficient for analytical
purposes. Transfer to a sieve having circular openings 1/25 inch (1 mm.) in diameter,
sift, breaking the lumps with a soft rubber pestle. Grind in a mortar the part re-
maining on the sieve until the particles will pass through. Mix thoroughly and
preserve in tightly stoppered bottles. Grind and sift as rapidly as possible to
avoid loss or gain of moisture during the operation.

3 MOISTURE.— OFFICIAL.

Heat 2 grams of the sample prepared as in 2 for 5 hours in a water oven at the
temperature of boiling water. In the case of potash salts, sodium nitrate, and
ammonium sulphate heat at about 130°C. to constant weight. The loss in weight
is considered as moisture.

TOTAL PHOSPHORIC ACID.

Gravimetric Method. — Official.

4 REAGENTS.

(a) Molybdate solution. — Dissolve 100 grams of molybdic acid in dilute ammo-
nium hydroxid (144 cc. of ammonium hydroxid (sp. gr. 0.90) and 271 cc. of water);
pour this solution slowly and with constant stirring into dilute nitric acid i 189 cc. of
nitric acid (sp. gr. 1.42) and 1148 cc. of water). Keep the mixture in a warm place
for. several days or until a portion heated to 40°C. deposits no yellow precipitate
of ammonium phosphomolybdate. Decant the solution from any sediment and
preserve in glass-stoppered vessels.

(b) Ammonium nitrate solution. — Dissolve 200 grams of commercial ammonium
nitrate, phosphate free, in water and dilute to 2 liters.

(C) Magnesia mixture. — Dissolve 22 grams of recently ignited calcined magnesia
in dilute hydrochloric acid, avoiding an excess of the latter. Add a little calcined
magnesia in excess, and boil a few minutes to precipitate iron, aluminium, and phos-

1

2 METHODS OF ANALYSIS [Chap.

phoric acid; filter; add 280 grams of ammonium chlorid, 261 cc. of ammonium hydrox-
id (sp. gr. 0.90) and dilute to 2 liters. Instead of the solution of 22 grams of cal-
cined magnesia, 110 grams of crystallized magnesium chlorid (MgCl26H20) dissolved
in water may be used, then add 280 grams of ammonium chlorid and proceed as above.

(d) Dilute ammonium hydroxid for washing. — Dilute 100 cc. of ammonium hy-
droxid (sp. gr. 0.90) to 1 liter.

(e) Magnesium nitrate solution. — Dissolve 320 grams of calcined magnesia in
nitric acid, avoiding an excess of the latter; then add a little calcined magnesia in
excess, boil, filter from the excess of magnesia, ferric oxid, etc., and dilute to 2 liters.

5 PREPARATION OF SOLUTION.

Treat 2 or 2.5 grams of the sample by one of the methods given below:

(a) Ignite, and dissolve in hydrochloric acid.

(b) Evaporate with 5 cc. of magnesium nitrate, ignite, and dissolve in hydro-
chloric acid.

(C) Boil with 20-30 cc. of strong sulphuric acid in a Kjeldahl flask, adding 2—1
grams of sodium or potassium nitrate at the beginning of the digestion and a small
quantity after the solution has become nearly colorless, or adding the nitrate in
small portions from time to time. After the solution is colorless add 150 cc. of water,
and boil for a few minutes.

(d) Digest in a Kjeldahl flask with strong sulphuric acid and such other re-
agents as are used in either the plain or modified Kjeldahl or Gunning method for
estimating nitrogen. Do not add any potassium permanganate, but after the
solution has become colorless add about 100 cc. of water and boil for a few minutes.

(e) Dissolve in 30 cc. of concentrated nitric acid and a small quantity of hydro-
chloric acid and boil until organic matter is destroyed.

(f) Add 30 cc. of concentrated hydrochloric acid, heat and add cautiously, in
small quantities at a time, about 0.5 gram of finely pulverized potassium chlorate
to destroy organic matter.

(£) Dissolve in 15-30 cc. of strong hydrochloric acid and 3-10 cc. of nitric acid.
This method is recommended for fertilizers containing much iron or aluminium
phosphate.

After solution, cool, dilute to 200 cc. or to 250 cc. if a 2.5 gram sample was used.
Mix, and pour on a dry filter.

6

DETERMINATION.

Take an aliquot of the solution prepared as directed above, corresponding to 0.25
gram, 0.50 gram, or 1 gram, neutralize with ammonium hydroxid, and clear with a
few drops of nitric acid. In case Irydrochloric or sulphuric acid has been used as
a solvent, add about 15 grams of dry ammonium nitrate or a solution containing
that amount. To the hot solution add 60-80 cc. of the molybdate solution for every
decigram of phosphoric acid (P205) that is present. Digest at about 65°C. for an
hour, and determine if the phosphoric acid has been completely precipitated by
the addition of more molybdate solution to the clear supernatant liquid. Fil-
ter and wash with cold water or, preferably, ammonium nitrate solution. Dissolve
the precipitate on the filter with ammonium hydroxid and hot water and wash
into a beaker to a bulk of not more than 100 cc. Nearly neutralise with hydrochloric
acid, cool, and add magnesia mixture from a burette; add slowly (about 1 drop per
second), stirring vigorously. After 15 minutes add 12 cc. of ammonium hydroxid
(sp. gr. 0.90). Let stand till the supernatant liquid is clear (2 hours is usually
enough) filter, wash with the dilute ammonium hydroxid until the washings are

I] FERTILIZERS 3

practically free from chlorin, dry the filter and precipitate and transfer the latter
to a weighed porcelain crucible. Ignite the filter separately and add its ash to the
precipitate in the crucible. Ignite to whiteness or to a grayish white, weigh, and
calculate to phosphoric acid (P2O5).

Volumetric Method. — Official.

7 REAGENTS.

(a) Molybdate solution. — To 100 cc. of molybdate solution prepared as directed
in 4 (a), add 5 cc. of nitric acid (sp. gr. 1.42). This solution should be filtered im-
mediately before using.

(b) Standard sodium or -potassium hydroxid solution. — Dilute 323.81 cc. of N/1
alkali, free from carbonates, to 1 liter. 100 cc. of the solution should neutralize
32.38 cc. of N/1 acid; 1 cc. is equivalent to 1 mg. of P205 (1% of P205 on a basis of
0.1 gram of substance).

(C) Standard acid solution. — Prepare an acid solution corresponding to the,
or to one-half of the, strength of (D), and standardize by titration against that
solution, using phenolphthalein as indicator. Hydrochloric or nitric acid may be
used.

(d) Phenolphthalein solution. — Dissolve 1 gram of phenolphthalein in 100 cc. of
alcohol.

8 PREPARATION OF SOLUTION.

Dissolve according to 5 (b), (e), (f), or (£), preferably by (e), when these acids
are a suitable solvent, and dilute to 200 cc. with water.

9 DETERMINATION.

(a) For percentages of 5 or below use an aliquot corresponding to 0.4 gram of
substance, for percentages between 5 and 20 use an aliquot corresponding to 0.2
gram of substance, and for percentages above 20 use an aliquot corresponding to
0.1 gram of substance. Add 5-10 cc. of nitric acid, depending on the method of
solution (or the equivalent in ammonium nitrate), nearly neutralize with ammonium
hydroxid, dilute to 75-100 cc, heat in a water bath to 60°-65°C, and for percentages
below 5 add 20-25 cc. of freshly filtered molybdate solution. For 'percentages be-
tween 5 and 20 add 30-35 cc. of molybdate solution. For percentages greater than
20 add sufficient molybdate solution to insure complete precipitation. Stir, let
stand in the bath about 15 minutes, filter at once, wash once or twice with water by
decantation, using 25-30 cc. each time, agitate the precipitate thoroughly and
allow to settle; transfer to the filter and wash with cold water until the filtrate from
2 fillings of the filter yields a pink color upon the addition of phenolphthalein and 1
drop of the standard alkali. Transfer the precipitate and filter to a beaker or pre-
cipitating vessel, dissolve the precipitate in a small excess of the standard alkali,
add a few drops of phenolphthalein solution, and titrate with the standard acid.

(b) Proceed as in (a) with this exception: Heat in a water bath at 45°-50oC.,
add the molybdate solution, and allow to remain in the bath with occasional stirring
for 30 minutes.

(C) Proceed as in (a) to the point where the solution is ready to place in the

water bath. Then cool the solution to room temperature, add molybdate solution

at the rate, of 75 cc. for each decigram of phosphoric acid presenl . place 1 be stoppered

lining the solution in a shaking apparatus and shake 'i<>r 30 minutes at

room temperature, filter at once, wash, and titrate as in (a).

4 METHODS OF ANALYSIS [Chap.

WATER-SOLUBLE PHOSPHORIC ACID.

1 0 Gravimetric Method. — Official.

Place 2 grams of the sample on a 9 cm. filter, wash with successive small portions
of water, allowing each portion to pass through before adding more, until the filtrate
measures about 250 cc. If the filtrate is turbid, add a little nitric acid. Make up
to any convenient volume, mix well, use an aliquot, and proceed as under 6.

11 Volumetric Method. — Official.

Treat the sample as directed under 10. To an aliquot of the solution cor-
responding to 0.2 or 0.4 gram, add 10 cc. of concentrated nitric acid and ammonium
hydroxid until a slight permanent precipitate is formed, dilute to 60 cc, and pro-
ceed as directed under 9.

CITRATE-INSOLUBLE PHOSPHORIC ACID.— OFFICIAL.

12 REAGENTS.

In addition to the reagents given under 4 and 7 prepare ammonium citrate solu-
tion by one of the following methods:

Ammonium citrate solution. — (1) Dissolve 370 grams of commercial citric acid
in 1500 cc. of water; nearly neutralize with commercial ammonium hydroxid; cool;
add ammonium hydroxid until exactly neutral (testing with litmus or azolitmin
paper), and dilute sufficiently to make the specific gravity 1.09 at 20°C. The vol-
ume will be about 2 liters; or,

(2) To 370 grams of commercial citric acid add commercial ammonium hydroxid
until nearly neutral; reduce the specific gravity to slightly more than 1.09 at 20°C.
and make exactly neutral, testing as follows: Prepare a solution of fused calcium
chlorid, 200 grams to the liter, and add 4 volumes of strong alcohol. Make this
solution exactly neutral, using a small amount of freshly prepared corallin solution
as preliminary indicator, and test finally by withdrawing a portion, diluting with
an equal volume of water, and testing with cochineal solution; 50 cc. of this solution
will precipitate the citric acid from 10 cc. of the citrate solution. To 10 cc. of the
nearly neutral citrate solution add 50 cc. of the alcoholic calcium chlorid solution,
stir well, filter at once through a folded filter, dilute with an equal volume of
water, and test the reaction with neutral solution of cochineal. If acid or alkaline,
add ammonium hydroxid or citric acid, as the case may be, to the citrate solution,
mix, and test again, as before. Repeat this process until a neutral reaction is
obtained. Add sufficient water to make the specific gravity 1.09 at 20°C.

1 3 DETERMINATION.

(a) Acidulated samples. — Heat 100 cc. of strictly neutral ammonium citrate
solution (sp. gr. 1.09) to 65°C. in a 250 cc. Erlenmeyer flask placed in a warm water
bath, keeping the flask loosely stoppered to prevent evaporation. The level of the
water in the bath should be above that of the citrate solution in the flask. When
the citrate solution has reached 65°C, drop into it the filter containing the washed
residue from the water-soluble phosphoric acid solution in 10, close tightly with
a smooth rubber stopper, and shake violently until the filter paper is reduced to
a pulp, relieving the pressure by momentarily removing the stopper. Place the
flask in the bath and maintain its contents at exactly 65°C. Shake the flask every
'> minutes. At the expiration of exactly 30 minutes from the time the filter and the
residue are introduced, remove the flask from the bath and immediately filter the
contents as rapidly as possible through a quick-acting filter paper. Wash with

I] FERTILIZERS 5

water at 65°C. until the volume of the filtrate is about 350 cc, allowing time for
thorough draining before adding new portions of water. (1) Transfer the filter
and its contents to a crucible, ignite until all organic matter is destroyed, add 10-
15 cc. of strong hydrochloric acid, and digest until all phosphate is dissolved; or,
(2) Return the filter with contents to the digestion flask, add 30-35 cc. of strong
nitric acid, 5-10 cc. of strong hydrochloric acid, and boil until all phosphate is dis-
solved. Dilute the solution as prepared in (1) or (2) to 200 cc. If desired, the filter
and its contents may be treated according to methods 5 (b), (C) or (d). Mix well,
filter through a dry filter and proceed as directed under 6 or 9.

(b) Non-acidulated samples. — In case a determination of citrate-insoluble phos-
phoric acid is required in non-acidulated samples treat 2 grams of the phosphatic
material without previous washing with water, precisely as in (a), except when the
substance contains much animal matter (bone, fish, etc.), in which case dissolve
the residue insoluble in ammonium citrate by any one of the processes described
under 5 (b), (C) or (d) and determine phosphoric acid as directed in 6 or 9.

14 CITRATE-SOLUBLE PHOSPHORIC ACID.— OFFICIAL.

The sum of the water-soluble and citrate-insoluble subtracted from the total
gives the citrate-soluble phosphoric acid.

15 DETECTION OF NITRATES.— OFFICIAL.

Mix 5 grams of the fertilizer with 25 cc. of hot water and filter. To a portion of
this solution add 2 volumes of concentrated sulphuric acid, free from nitric acid and
oxids of nitrogen, and allow the mixture to cool. Add cautiously a few drops of a
concentrated solution of ferrous sulphate so that the fluids do not mix. If nitrates
are present the junction shows at first a purple, afterwards a brown, color or if only
a very minute quantity be present, a reddish color. To another portion of the solu-
tion add 1 cc. of a 1% solution of sodium nitrate and test as before to determine
whether sufficient sulphuric acid were added in the first test.

ORGANIC AND AMMONIACAL NITROGEN ONLY.

Kjeldahl Method. — Official.

16 REAGENTS.

For ordinary work N/2 acid is recommended. For work in determining very
small amounts of nitrogen N/10 acid is recommended. In titrating mineral acids
against ammonium hydroxid solution use cochineal or methyl red as indicator.

fa) Standard hydrochloric acid. — Determine the absolute strength as follows:
Preliminary test. — Place a measured portion of the acid to be standardized in an
Erlenmeyer flask with excess of calcium carbonate, to neutralize free acid, and a
few drops' of potassium chromate as indicator. By titration with silver nitrate
solution determine exactly the quantity required to precipitate the chlorin. Final
determination. — To a measured portion of the acid to be standardized add from the
burette 1 drop in excess of the required quantity of silver nitrate solution as deter-
mined by the preceding test. Heat to boiling, protect from the light, and allow to
stand until the precipitate is granular. Filter on a tared Gooch crucible, previously
healed to 140°-150°C, wash with hot water, testing the filtrate to prove exeess of
silver nitrate. Dry the silver chlorid at 140°-150°C, cool and weigh.

(b) Standard .sulphuric acid. — Determine the absolute strength of the acid by
precipitation with barium chlorid solution as follows: Dilute a measured quantity
of the acid to be standardized to approximately 100 cc, heat to boiling and add drop

6 METHODS OF ANALYSIS [Chap.

by drop a 10 % solution of barium chlorid until no further precipitation occurs.
Continue the boiling for about 5 minutes, allow to stand for 5 hours or longer in a
warm place, pour the supernatant liquid on a tared Gooch or on an ashless filter,
treat the precipitate with 25-30 cc. of boiling water, transfer to the filter and wash
with boiling water until the nitrate is free from chlorin. Dry, ignite over a Bunsen
burner and weigh as barium sulphate.

(C) Standard alkali solution. — Accurately determine the strength of this solution
by titration against the standard acid. N/10 solution is recommended.

(d) Sulphuric acid. — Sp. gr. 1.84 and free from nitrates and ammonium sulphate.

(e) Metallic mercury, or mercuric oxid. — Mercuric oxid should be prepared in the
wet way, but not from mercuric nitrate.

(f) Copper sulphate. — Crystallized.

(£) Potassium permanganate. — Finely pulverized.

(h) Granulated tine or pumice stone. — Added to the contents of the distillation
flask if necessary to prevent bumping.

(i) Potassium sulphid solution. — Dissolve 40 grams of commercial potassium
sulphid in 1 liter of water.

(j) Sodium hijdroxid solution. — A saturated solution, free from nitrates.

(k) Cochineal solution. — Digest, with frequent agitation, 3 grams of pulverized
cochineal in a mixture of 50 cc. of strong alcohol and 200 cc. of water for 1 or 2 days
at ordinary temperature, and then filter.

(1) Methyl red solution. — Dissolve 1 gram of methyl red (dimethyl-amino-azo-
benzene-ortho-carbonic acid) in 100 cc. of 95% alcohol.

1 7 APPARATUS.

(a) Kjeldahl flasks for both digestion and distillation. — Total capacity of about
550 cc, made of hard, moderately thick, and well-annealed glass.
. (b) Distillation flasks. — For distillation any suitable flask of about 550 cc. capac-
ity may be used. It is fitted with a rubber stopper through which passes the lower
end of a Kjeldahl connecting bulb to prevent sodium hydroxid being carried over
mechanically during distillation. The bulb should be about 3 cm. in diameter, and
the tubes should be of the same diameter as the condenser tube with which the upper
end of the bulb tube is connected by means of rubber tubing.

18

DETERMINATION.

Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be
analyzed in a digestion flask with approximately 0.7 gram of mercuric oxid, or its
equivalent in metallic mercury, and add 20-30 cc. of sulphuric acid (0.1-0.3 gram of
crystallized copper sulphate may also be used in addition to the mercury, or in
place of it). Place the flask in an inclined position and heat below the boiling
point of the acid until frothing has ceased. (A small piece of paraffin may be added to
prevent extreme foaming.) Then raise the heat until the acid boils briskly and 1 1
for a time after the mixture is colorless or nearly so, or until oxidation is complete.
Remove the flask from the flame, hold it upright, and while still hot add care-
fully potassium permanganate in small quantities at a time until, after shaking,
the liquid remains green or purple.

After cooling dilute with about 200 cc. of water, add a few pieces of granulated
zinc or pumice stone, if necessary to prevent bumping, ami L'"» ee. of potassium sul-
phid solution with shaking. Next add sufficient sodium hydroxid solution to make
the reaction strongly alkaline, 50 ee. are usually enough, pouring it down the side of
the Mask so that it does not mix at once with the arid solution. Connect the flask

I] FERTILIZERS 7

with the condenser, mix the contents by shaking, distil until all ammonia has passed
over into a measured quantity of the standard acid and titrate with the standard
alkali. The first 150 cc. of the distillate will generally contain all the ammonia.

The use of mercuric oxid in this operation greatly shortens the time necessary
for digestion, which is rarely over an hour and a half in case of substances most
difficult to oxidize, and is more commonly less than an hour. In most instances
the use of potassium permanganate is quite unnecessary, but it is believed that in
exceptional cases it is required for complete oxidation, and in view of the uncer-
tainty it is always used. The potassium sulphid removes all the mercury from the
solution, and so prevents the formation of mercuro-ammonium compounds which
are not completely decomposed by the sodium hydroxid. The addition of zinc
gives rise to an evolution of hydrogen and prevents violent bumping.

Previous to use the reagents should be tested by a blank experiment with sugar.
The sugar partially reduces any nitrates present that might otherwise escape notice.

Gunning Method. — Official.

19 REAGENTS.

Potassium sulphate. — Pulverized.

The other reagents and standard solutions used are described under 16.

20 APPARATUS.

The apparatus used is described under 17.

21

DETERMINATION.

Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be
analyzed in a digestion flask. Add 10 grams of powdered potassium sulphate and
15-25 cc. (ordinarily about 20 cc.) of sulphuric acid (0.1-0.3 gram of crystallized
copper sulphate may also be added). Conduct the digestion as in the Kjeldahl
process, starting with a temperature below the boiling point and increasing the heat
gradually until frothing ceases. Digest for a time after the mixture is colorless or
nearly so, or until oxidation is complete. Do not add either potassium permanganate
or potassium sulphid. Cool, dilute, neutralize, distil, and titrate with the standard
alkali. In neutralizing before distilling it is convenient to add a few drops of
phenolphthalein indicator or litmus paper. The pink color given by phenolphthal-
ein indicating an alkaline reaction is destroyed by a considerable excess of strong
fixed alkali.

Kjeldahl-Gunning-A mold Method. — Official.

22 REAGENTS AND APPARATUS.

Described under 16, 17 and 19.

23

DETERMINATION.

Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be
analyzed in a digestion flask. Add 15-18 grams of potassium sulphate, i gram of
copper sulphate, 1 gram of mercuric oxid, or its equivalent in metallic mercury,
and 25 cc. of sulphuric acid. Heal gently until frothing ceases, | hen boil i he mixture
briskly, and continue the digestion for a time after the mixture is colorless or nearly
so or until oxidation is complete. Cool, dilute with aboul 200 cc. of water, add 50 cc.
of potassium sulphid solution, make strongly alkaline with sodium hydroxid solu-
tion and complete the determination as directed under 18.

8 METHODS OF ANALYSIS [Chap.

TOTAL NITROGEN.
Kjeldahl Method Modified to include the Nitrogen of Nitrates. — Official.

24 REAGENTS.

(a) Zinc dust. — Impalpable powder. Granulated zinc or zinc filings will not
answer.

(b) Sodium thiosulphate.

(C) Commercial salicylic acid.

The other reagents and standard solutions are described under 16.

25 APPARATUS.

The apparatus used is described under 1 7.

26 DETERMINATION.

Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be
analyzed in a Kjeldahl digestion flask. (1) Add 30 cc. of sulphuric acid containing

1 gram of salicylic acid, shake until thoroughly mixed, allow to stand for at least
30 minutes, and then add 5 grams of crystallized sodium thiosulphate and digest as
directed below; or, (2) Add to the substance 30 cc. of sulphuric acid containing 2
grams of salicylic acid, allow to stand at least 30 minutes and then add gradually

2 grams of zinc dust, shaking the contents of the flask at the same time and digest
as follows:

Place the flask on the stand for holding the digestion flasks and heat over a low
flame until all danger from frothing has passed. Then raise the heat until the acid
boils briskly and continue the boiling until white fumes no longer escape from the
flask. This requires about 5-10 minutes. Add approximately 0.7 gram of mercuric
oxid, or its equivalent in metallic mercury, and continue the boiling until the liquid
in the flask is colorless, or nearly so. In case the contents of the flask are likely to
become solid before this point is reached, add 10 cc. more of sulphuric acid. Complete
the oxidation with a little potassium permanganate in the usual way and proceed
as directed under 18. The reagents should be tested by blank experiments.

Gunning Method Modified to include the Nitrogen of Nitrates. — Official.

27 REAGENTS AND APPARATUS.

The reagents and standard solutions are described under 16, 17, 19 and 24.
J

28 DETERMINATION.

Place 0.7-3.5 grams, according to the nitrogen content, of the substance to be
analyzed in a digestion flask. Add 30-35 cc. of salicylic acid mixture (30 cc. of sul-
phuric acid to 1 gram of salicylic acid); shake until thoroughly mixed, and allow to
stand for at least 30 minutes with frequent shaking. Add 5 grams of sodium thio-
sulphate and heat the solution for5minutes; cool; add 10 grams of potassium sulphate
and heat very gently until foaming ceases, then strongly until nearly colorless,
and proceed as directed under 21 .

Absolute or Cupric Oxid Method. — Official.

29 REAGENTS.

(a) Coarse cupric oxid. — Ignite and cool before using.

(b) Fine cupric oxid. — Grind (a).

I]

FERTILIZERS

(C) Metallic copper. — Granulated copper, or fine copper gauze, heated and cooled
in a current of hydrogen or by dropping the heated copper into a test tube containing
a few cc. of methyl alcohol.

(d) Sodium bicarbonate. — Free from organic matter.

(e) Caustic potash solution. — A supersaturated solution of caustic potash in hot
water.

30 APPARATUS.

(a) Combustion tube. — Hard Bohemian glass, about 65 cm. long, 12.7 mm. internal
diameter and sealed at one end.

(b) Azotometer. — Capacity 100 cc, accurately calibrated.

(C) Sprengel mercury air pump.

(d) Small paper scoop. — Made from stiff writing paper.
i

31 DETERMINATION.

Use 1-2 grams of ordinary commercial fertilizers. In the case of highly nitrogen-
ized substances, the amount to be used is governed by the amount of nitrogen esti-
mated to be present. Fill the tube (Fig. 1) as follows: (1) about 5 cm. of coarse

XL

X-

1H

I

<ZT**?m ■'■■ '-•■ ' ■•-■■' ■•■•■lf»Jj-tS;'AV''.''*.l««.*l.'i**.t',V.«t.'A'«V«'Jtma

^v.v:-.:-jj.-;.-,- ■-■■,■ ■.•■■■■ :g>^«v^v>^vSvA<:.'/A%v;,.^>.'V^^

11

M\

5 CM. IO CM.

COAffSE SUBSTANCE
OX ID. AND F/.VE OXID.

so cm.

COARSE OXID.

r cm. 6 cm.

METALLIC COAfBl
COPPER. OXID.

ASBBiTOA
PLU6.

2. 5 CM-
FREE EHO

50DIUM
BICARBONATE-

THE ROMAN NUMERALS REFER TO THE ORDER IN WHICH THE DIFFERENT
PORTIONS ARE TO BE HEATED.

FIG. 1.

cupric oxid; (2) place on the small paper scoop a sufficient amount of the fine cupric
oxid which, when mixed with the substance to be analyzed, will fill about 10 cm. of
the tube; pour on this the substance, rinsing the watch glass with a little of the fine
oxid, and mix thoroughly with a spatula, pour into the tube, rinsing the scoop with
a little fine oxid; (3) about 30 cm. of coarse cupric oxid; (4) about 7 cm. of metallic
copper; (5) about 6 cm. of coarse cupric oxid; (6) a small plug of asbestos; (7) 0.8-1
gram of sodium bicarbonate; (8) a large loose plug of asbestos.

After the tube is filled hold in a horizontal position and tap gently on the table
in order that a canal may be formed in the upper portion of the fine cupric oxid.
Place the tube in the combustion furnace, leave about 2.5 cm. of it projecting and
connect with the pump by a rubber stopper Bmeared with glycerol, taking care to
make the connection perfectly tight. In order to protect the latter from the heat,
place an asbestos plate, having a circular opening in the center, over the projecting
end of the tube.

Exhaust the air from the tube by means of the pump. When a vacuum lias been
obtained, allow the flow of mercury to continue; light the gas under thai part of the

10 METHODS OF ANALYSIS [Chap.

tube containing the metallic copper, the anterior layer of cupric oxid and the sodium
bicarbonate. As soon as the vacuum is destroyed and he apparatus filled w th
carbon dioxid, shut off the flow of mercury and at once introduce the delivery tube
of the pump into the receiving arm of the azotometer just below the surface of the
mercury seal so that the escaping bubbles will pass into the air and not into the tube,
to avoid the useless saturation of the caustic potash solution.

When the flow of carbon dioxid has very nearly or completely ceased, pass the
delivery tube down into the receiving arm so that the bubbles will escape into the
azotometer. Light the gas under the 30 cm. layer of oxid, heat gently for a few
minutes, to drive out any moisture that may be present, and then bring to a red heat.
Heat gradually the mixture of substance and oxid, lighting a jet at a time. Avoid
a too rapid evolution of bubbles, which should be allowed to escape at the rate
of about one per second or a little faster. When the burners under the mixture have
all been turned on, light the gas under the layer of oxid at the end of the tube.
When the evolution of bubbles has ceased, turn out all the burners except those
under the metallic copper and anterior layer of oxid, and allow to cool for a few min-
utes. Exhaust with the pump and remove the azotometer before the flow of mercury
has stopped. Break the connection of the tube with the pump, stop the flow of
mercury, and extinguish the burners. Allow the azotometer to stand for at least
an hour, or cool with a stream of water until the volume and temperature become
constant.

Adjust accurately the level of the potassium hydroxid solution in the bulb to
that in the azotometer; note the volume of the nitrogen, temperature, and height of
barometer; calculate the weight of the nitrogen as usual.

AMMONIACAL NITROGEN.

32 Magnesium Oxid Method. — Official.

Place 0.7-3.5 grams, according to the ammonia content, of the substance to be
analyzed in a distillation flask with about 200 cc. of water and 5 grams or more of
magnesium oxid, free from carbonates. Then connect the flask with a condenser and
distil 100 cc. of the liquid into a measured quantity of standard acid and titrate
with standard alkali solution.

NITRIC AND AMMONIACAL NITROGEN.

33 Ulsch-Street Method. — Official.

Place 1 gram of the sample in a half-liter flask, add about 30 cc. of water and 2-3
grams of reduced iron, and, after standing sufficiently long to insure solution of the
soluble nitrates and ammonium salts, add 10 cc. of a mixture of strong sulphuric acid
with an equal volume of water; shake thoroughly, place a long-stemmed funnel in the
neck of the flask to prevent mechanical loss, and allow to stand for a short time until
the violence of the reaction has moderated. Heat the solution slowly, boil for 5
minutes, and cool. Add about 100 cc. of water, a little paraffin, and 7-10 grams of
magnesium oxid, free or nearly free from carbonates. Connect with a condenser,
such as is used in the Kjeldahl method, and boil the mixture for 40 minutes, nearly
to dryness; collect the ammonia in a measured quantity of standard acid, and titrate
with standard alkali solution in the usual manner. The nitrogen obtained represents
the nitrates plus the ammonium salts contained in the sample.

In the analysis of nitrate salts proceed as above, except that 25 cc. of the nitrate
solution, equivalent to 0.25 gram of the sample, are employed with 5 grams oi re-
duced iron After boiling add 75 cc. of water and an excess of sodium hydroxid
solution and complete the determination as above.

I] FERTILIZERS 11

34 Zinc-Iron Method. — Official.

Dissolve 10 grams of the sample in water and dilute to 500 cc. Place 25 cc. of
this solution, corresponding to 0.5 gram of the substance, in a 400 cc. distillation flask,
add 120 cc. of water, 5 grams of well-washed and dried zinc dust, and 5 grams of
reduced iron. To the solution add 80 cc. of saturated sodium hydroxid solution,
connect the flask with the condensing apparatus and conduct the distillation simul-
taneously with the reduction, collecting the ammonia in standard acid. Continue
the distillation until 100 cc. have been distilled and titrate with standard alkali
solution.,

NITROGEN IN NITRATE SALTS.

35 Ferrous Sulphate-Zinc-Soda Method. — Tentative.

Place 0.5 gram of the nitrate salt in a 600-700 cc. flask, add 200 cc. of water,
5 grams of powdered zinc, 1-2 grams of ferrous sulphate, and 50 cc. of sodium hy-
droxid solution (36° Baume). Connect with the distilling apparatus, distil, collect
the distillate in the usual way in N/10 sulphuric acid and titrate with standard
alkali solution, a

ORGANIC NITROGEN SOLUBLE IN NEUTRAL PERMANGANATE.— OFFICIAL.

36 Preliminary Test (Determination of Water-Insoluble Organic Nitrogen).

Place 1 gram of the material on an 11 cm. filter paper and wash with water at
room temperature until the filtrate measures 250 cc. Dry and determine nitrogen
in the residue as in 18 or 21, making a correction for the nitrogen of the filter,
if necessary.

37 DETERMINATION.

Place a quantity of the fertilizer, equivalent to 50 mg. of water-insoluble organic
nitrogen as determined in 36, on a moistened 11 cm. filter paper and wash with water
at room temperature until the filtrate measures 250 cc. Transfer the insoluble
residue with 25 cc. of tepid water to a 300 cc. Griffin low-form beaker, add 1 gram
of sodium carbonate, mix, and add 100 cc. of 2% permanganate. Cover with a
watch glass and immerse for 30 minutes in a steam or hot water bath so that the level
of the liquid in the beaker is below that of the water in the bath. Stir twice at inter-
vals of 10 minutes. At the end of the digestion remove from the bath, add immedi-
ately 100 cc. of cold water, and filter through a heavy 15 cm. folded filter. Wash
with small quantities of cold water until the filtrate measures about 400 cc. De-
termine nitrogen in the residue and filter, as in 18 or 21 , correcting for the nitrogen
contained in the latter. The nitrogen thus obtained is the inactive water-insoluble
organic nitrogen. Subtract this result from that obtained in 36 to obtain the
percentage of organic nitrogen soluble in neutral permanganate.

ORGANIC NITROGEN SOLUBLE IN ALKALINE PERMANGANATE.— OFFICIAL.
(Not applicable to fertilizers containing cottonseed meal or castor pomace.)

38 PREPARATION OF SAMPLE.

(a) Mixed fertilizer s . — Place an amount of material, equivalent to 50 mg. of water-
insoluble organic nitrogen determined as directed under 36, on a filter paper and
wash with water at room temperature until the filtrate measures 250 cc.

12 METHODS OF ANALYSIS [Chap.

(b) Raw materials. — Place an amount of material, equivalent to 50 mg. of water-
insoluble organic nitrogen determined as directed under 36, in a small mortar, add
about 2 grams of powdered rock phosphate, mix thoroughly, transfer to a filter paper,
and wash with water at room temperature until the filtrate measures 250 cc.
When much oil or fat is present, it is well to wash with ether before extracting with
water.

39 DETERMINATION.

Dry the residue of 38 at a temperature not exceeding 80°C. and transfer from the
filter to a 500-600 cc. Kjeldahl distillation flask. Add 20 cc. of water, 15-20 small
glass beads, or fragments of pumice stone, a piece of paraffin the size of a pea, and
100 cc. of alkaline permanganate solution (25 grams of pure potassium permanganate
and 150 grams of sodium hydroxid, separately dissolved in water, the solutions cooled,
mixed, and made to a volume of 1 liter). Connect with an upright condenser to
the lower end of which a receiver containing standard acid has been attached.
Digest slowly, for at least 30 minutes, below distillation point, with a very low flame,
using coarse wire gauze and asbestos paper between the flask and flame. Gradually
raise the temperature and, after any danger from frothing has passed, distil until
95 cc. of the distillate are obtained, and titrate as usual. When a tendency to froth
is noticed, lengthen the digestion period and no trouble will be experienced when the
distillation is begun. During the digestion gently rotate the flask occasionally,
particularly if the material shows a tendency to adhere to the sides.. The nitrogen
thus obtained is the active water-insoluble organic nitrogen.

POTASH.

Method I.
Lindo-Gladding Method. — Official.

40 REAGENTS.

(a) Ammonium chlorid solution. — Dissolve 100 grams of ammonium chlorid in
500 cc. of water, add 5-10 grams of pulverized potassium-platinic chlorid, and shake
at intervals for 6-8 hours. Allow the mixture to settle overnight and filter. The
residue may be used for the preparation of a fresh supply.

(b) Platinum solution. — A platinic chlorid solution containing the equivalent of
1 gram of metallic platinum (2.1 grams of H2PtCl6) in every 10 cc.

(C) 80% alcohol. — Sp. gr. 0.8645 at -15-o-. Denatured alcohol, made up according
to formula 1 (U. S. Internal Rev., Reg. No. 30, Revised, Aug. 22, 1911, p. 45) and di-
luted with water to make 80% alcohol by volume, may also be used.

41

PREPARATION OF SOLUTION.

(a) Mixed fertilizers. — Place 2.5 grams of the sample upon a 12.5 cm. filter paper
and wash with boiling water until the filtrate amounts to about 200 cc. Add to the
filtrate 2 cc. of concentrated hydrochloric acid, heat to boiling, transfer to a 250 cc.
graduated flask and add to the hot solution a slight excess of ammonium hydroxid
and sufficient ammonium oxalate to precipitate all the lime present, cool, dilute to
250 cc, mix, and pass through a dry filter.

(b) Potash salts; muriate and sulphate of potash, sulphate of potash and magnesia,
and kainit. — Dissolve 2.5 grams and dilute to 250 cc. without the addition of am-
monium hydroxid and ammonium oxalate.

(C) Organic compounds. — When it is desired to determine the total amount of
potash in organic substances, such as cottonseed meal, tobacco stems, etc., saturate

I] FERTILIZERS 13

10 grams of the sample with strong sulphuric acid and ignite in a muffle at a low red
heat to destroy organic matter. Add a little strong hydrochloric acid, warm slightly
in order to loosen the mass rom the dish, transfer to a 250 cc. graduated flask, add
ammonia and ammonium oxalate and proceed as in (a). "

42

DETERMINATION.

(a) Mixed fertilizers. — Evaporate 50 cc. of the solution in 41 (a) nearly to dryness,
add 1 cc. of dilute sulphuric acid (1 to 1), evaporate to dryness, and ignite to white-
ness. Maintain a full red heat until the residue is perfectly white. Dissolve the
residue in hot water, using at least 20 cc. for each decigram of potassium oxid pres-
ent, add a few drops of hydrochloric acid, and platinum solution in excess. Evap-
orate on a water bath to a thick paste. Treat the residue with 80% alcohol, avoid-
ing exposure to ammonia. Filter, wash the precipitate thoroughly with 80% alco-
hol both by decantation and on the filter, continuing the washing after the filtrate
is colorless. Then wash with 10 cc. of the ammonium chlorid solution to remove
impurities from the precipitate and repeat 5 or 6 times. Wash again thoroughly
with 80% alcohol and dry the precipitate for 30 minutes at 100°C. Weigh and cal-
culate to potassium oxid. The precipitate should be perfectly soluble in water.

(b) Muriate of potash. — Acidify 50 cc. of the solution prepared according to 41
(b) with a few drops of hydrochloric acid, add 10 cc. of platinum solution and evapo-
rate to a thick paste. Treat the residue as under (a).

(C) Sulphate of potash; sulphate of potash and magnesia; and kainit. — Acidify
50 cc. of the solution prepared according to 41 (b) with a few drops of hydrochloric
acid and add 15 cc. of platinum solution. Evaporate the mixture and proceed as
directed under (a), except that 25 cc. portions of the ammonium chlorid solution
should be used.

(d) Water-soluble potash in wood ashes and cotton hull ashes. — Prepare the solution
according to 41 (a) and proceed as directed under (a), paying special attention to
the last sentence.

Method II.— Official.
(The Lindo-Gladding method is preferable in the presence of soluble sulphates.)

43 REAGENTS.

Described under 40.

44 PREPARATION OF SOLUTION.

Prepare the solution as directed under 41, omitting in all cases the addition of
ammonium hydroxid and ammonium oxalate.

45 DETERMINATION.

Dilute 25 cc. of the solution made as directed under 44 (50 cc. if less than
of potassium oxid be present) to 150 cc, heat to 100°C, and add, drop by drop, with
constant stirring, a slight excess of barium chlorid solution. Without filtering, add
in the same manner barium hydroxid solution in slight excess. Filter while hot and
wash until the precipitate is free from chlorin. Add to the lilt rate 1 cc. of strong
ammonium hydroxid, and then a saturated solution of ammonium carbonate until
the excess of barium is precipitated. Heat, and add, in tine powder, ()."> gram of
pure oxalic acid or 0.75 gram of ammonium oxalate, filter, wash free from chlorin,
evaporate the filtrate to dryness in a platinum dish, and ignite carefully over the free

14 METHODS OF ANALYSIS [Chap.

flame, below a red heat, until all volatile matter is driven off. Digest the residue
with hot water, filter through a small filter and dilute the filtrate, if necessary, so
that for each decigram of potassium oxid there will be at least 20 cc. of liquid. Acid-
ify with a few drops of hydrochloric acid and add platinum solution in excess. Evap-
orate on a water bath to a thick paste and treat the residue with 80% alcohol, both by
decantation and after collecting on a Gooch or other form of filter, dry for 30 minutes
at 100°C. and weigh. If there is an appearance of foreign matter in the double salt,
it should be washed as in 42 (a) with several portions of 10 cc. each of the
ammonium chlorid solution.

THOMAS OR BASIC SLAG.— TENTATIVE.

46 MECHANICAL ANALYSIS.
Proceed as directed under 1 , using 10 grams of material.

47 PREPARATION OF SAMPLE.
Prepare the sample as directed under 2.

TOTAL PHOSPHORIC ACID.
Gravimetric Method.

PREPARATION OF SOLUTION.

48

Prepare the solution for analysis as directed under 5 (e), or in strong hydrochloric
acid alone. In the latter case after the portion for analysis is measured out, add
nitric acid and heat for a few minutes.

49

DETERMINATION.

Dehydrate an aliquot (20 cc.) of 48 by evaporating to dryness on a steam o- hot
water bath; treat with 5 cc. of hydrochloric acid and 25 cc. of hot water; digest in
order to complete solution and filter off silica. From this point proceed as directed
under 6. Before precipitating with magnesia mixture, add 5 cc. of 5% sodium acetate.

50 Volumetric Method.

i

Prepare the solution as directed under 5 (e) and determine the phosphoric acid
in an aliquot of this solution as directed under 9, standardizing the solutions
against a standard phosphate material of approximately the same composition
as the sample under examination.

CITRATE-SOLUBLE PHOSPHORIC ACID.

Gravimetric Method. — (Wagner's Method.)

PREPARATION OF SOLUTION.

51

Weigh 5 grams of the slag into a 500 cc. Wagner flask containing 5 cc. of
alcohol. (The flask should have a neck width of at least 22 nun. and should be
marked at least S cm. below the mouth.) Make up to the mark with 2'", citric acid
solution of a temperature of 17.5°C. Fit the flask with a rubber stopper and place
at once in a rotary apparatus, shaking the flask for 30 minutes at the rate of 30-10
revolutions per minute, at the end of which time remove the Bask, filter immediately
on a dry filter and analyze the solution at once.

I] FERTILIZERS 15

52

DETERMINATION.

To 50 cc. of the clear filtrate in a beaker add 100 cc. of molybdate solution prepared
as directed under 4 (a). Place the beaker in a water bath, until the temperature
of the beaker's contents reaches 65CC, remove from the bath and cool to room tem-
perature. Filter and wash the yellow precipitate of ammonium phosphomolybdate
4 or 5 times with 1% nitric acid. Dissolve the precipitate in 100 cc. of cold 2%
ammonium hydroxid, nearly neutralize with hydrochloric acid and add to the solu-
tion, drop by drop, with continuous stirring, 15 cc. of magnesia mixture prepared as
directed under 4 (C) and proceed as under 6.

53 Volumetric Method.

In an aliquot of the clear solution prepared as in 51, determine the phosphoric
acid as directed under 9.

II. SOILS.

1 DIRECTIONS FOR TAKING SAMPLES.— OFFICIAL.

Sampling should be done preferably when the soil is reasonably dry. Remove
from the surface all vegetable material not incorporated with the soil. With a soil
auger or tube, whichever may be better adapted to the soil conditions, take a
sufficient number of sub-samples at properly distributed points to secure composite
samples representative of the entire tract.

(a) Surface soil. — Take a composite sample representative of the entire tract
to a depth of either (1) 6 inches, (2) the average depth of the plowed soil if this ex-
ceeds 6 inches, or (3) a maximum depth of 12 inches when there is no clear line of
demarcation between the soil and sub-soil above this depth.

(b) Sub-soil. — Take a composite sample of each important and distinctly different
soil stratum below the surface section already sampled to a total depth of 40 inches.
If a soil auger is used, before taking sub-soil samples the hole should be enlarged
and carefully cleaned out with the auger to prevent contamination of the several
substrata when the sample is being withdrawn.

Mix each composite sample thoroughly and, after cutting down by quartering to
about 2-4 pounds, air-dry in a cool, well-ventilated place.

It is recommended that the weight of a given volume of the soil as it lies in the
field be taken for calculating the percentage results obtained by analysis to pounds
per given area of the soil.

2 PREPARATION OF SAMPLE.— OFFICIAL.

After air-drying and weighing the sample, pulverize in a porcelain mortar, using
a rubber-tipped pestle to avoid the reduction of rock fragments, and pass through
a sieve with circular openings 1/25 inch (1 mm.) in diameter. Discard <he detritus
and weigh. Thoroughly mix the sifted material and preserve in a suitable stoppered
container.

For the quantitative determination of any of the constituents, prepare a very
finely pulverized sub-sample of the sifted material, using an agate mortar.

3 MOISTURE.-OFFICIAL.

Dry 2 or more grams of the sample, as prepared under 2, in a tared platinum dish
for 5 hours at the temperature of boiling water; cover the dish, cool in a desiccator,
and weigh rapidly to prevent the absorption of moisture. Heat, cool, and weigh
at intervals of 2 hours to constant weight. The loss of weight is reported as moisture.

4

VOLATILE MATTER.— OFFICIAL.

Meat the dish and dry soil from 3 to full redness, stirring occasionally, until all or-
ganic matter is destroyed. If the soil contains appreciable quant it ies of carbon
cool and moisten with a few drops of saturated ammonium carbonate solution, dry
and heat to dull redness to expel ammonium salts; cool in a desiccator and weigh.

17

18

METHODS OF ANALYSIS

[Chap.

ORGANIC CARBON.— OFFICIAL.
APPARATUS.

(a) A calorimeter bomb. — Use a type that permits the recovery and transfer of the
entire solid residue of the exploded charge to a small vessel by means of a jet of
water.

(b) Parr's apparatus for determining carbon dioxid.1 — Illustrated in Fig. 2.

FIG. 2. PARR'S APPARATUS FOR THE DETERMINATION OF CARBON DIOXID.

This consists of a 150 cc. Erlenmeyer flask (F) fitted with a 3-holed stopper through
2 of which the stems of 2 dropping funnels (S) and (A) extend almost to the bottom
of the flask. A capillary tube, passing through the third hole and flush with the
bottom of the stopper, connects with the gas burette (B).

(C) A simple Hemple gas pipette. — Contains 30% potassium hydroxid solution.

6 DETERMINATION.

Introduce 2 grams of soil as prepared under 2 (1 gram if high in organic matter),
0.75 gram of magnesium powder, and 10 grams of sodium peroxid, into the closed dry
calorimeter bomb, and mix thoroughly by shaking the bomb back and forth. Explode
the charge by means of an electric spark or by dropping a red hot plug into the bomb
through an automatic valve which closes immediately after the plug enters. Remove
the residue from the bomb, using as little hot water as possible, heat to boiling, and
transfer to the receiving funnel («S) of Parr's apparatus. From the acid funnel (A)
run 50 cc. of sulphuric acid (1 to 2) into the flask (F). Connect the apparatus and
slowly add the contents from the receiving funnel («S). The carbon dioxid gener-
ated passes through the capillary tube into the graduated burette (B). Heat the
contents of the flask (F) to boiling and boil for 1 minute, then force the gases into
the graduated burette (B) by introducing water into the flask (F) through the fun-
nel (S). Head the burette, recording the temperature and pressure. Pass the gas
into an ordinary absorption pipette containing 3D' J potassium hydroxid solution.
Shake the gas with the solution until carbon dioxid is wholly absorbed. Keturn the

II]

SOILS

19

residual gas to the graduated burette (B), and again read the burette noting the
temperature and pressure. The difference in readings calculated to standard con-
ditions of temperature and pressure gives the number of cc. of carbon dioxid derived
from the total carbon in the sample. Conduct a blank determination upon the
reagents used. If an appreciable amount of carbon dioxid is obtained in the blank,
the result expressed in terms of total carbon must be corrected accordingly.

Determine the inorganic carbon as directed under 9 and subtract it from the total
1 ~>btain the organic carbon.

shorn

ill

INORGANIC CARBON.
Modified Marr Method."1 — Tentative.

REAGENTS.

(a) N/10 hydrochloric acid.

(b) N/10 sodium hydroxid.

(C) Dilute hydrochloric acid. — Dilute 25 cc. of concentrated hydrochloric acid
(sp. gr. 1.19) to 250 cc. with carbon dioxid-free water.

(d) Barium hydroxid solution. — Prepare a saturated aqueous solution of barium
hydroxid, filter through asbestos into a large container through which air free
from carbon dioxid has been aspirated for some time, and provide an arrangement
whereby the solution may be delivered by air pressure or gravity and kept from
contact with carbon dioxid by means of soda lime tubes.

(e) Carbon dioxid-free water. — Use recently boiled and cooled water, or water
from which carbon dioxid has been removed by aeration for a sufficient length of
time with carbon dioxid-free air. Keep in a container provided with a similar
attachment as in (d).

8

APPARATUS.

HALF FULL OF

BEADS OR
BROKEN GLASS

FIG. 3. MODIFIED MARR APPARATUS FOR DETERMINING CARBON DIOXID.

The apparatus required (Fig. 3), consists of a tube 0-1), 50-00 cm. long, partly
filled with beads or broken glass and containing strong potassium hydroxid solution
(1 to 2), a cylindrical open top separator v funnel (£?), capacity 50 cc, marked at 20 and
40 cc, the stem of which extends almost to the bottom of the 250 cc. B nto the

*

20 METHODS OF ANALYSIS iChap.

mouth of which is fitted, by means of a rubber stopper, a section of glass tubing 10
cm. in length and 1 cm. internal diameter, which in turn is furnished with a side
tube extending through the condenser jacket (D), and connected by means of a rub-
ber stopper to the small trap (K), which is attached to the Meyer absorption ap
tus {E) as shown in the figure. The Meyer absorption apparatus is provided with 2
large bulbs, each of about 250 cc. capacity, and 10 smaller connecting bulbs, each of
about 10 cc. capacity. The connections between the various bulbs should have an
internal diameter of 8-10 mm. A perforated rubber stopper carrying 2 short ?
of capillary tubing each provided with rubber tubing and pinch-cocks (.V and 0
is fitted into the other opening of the Meyer absorption apparatus; (.V) is for the
addition of reagents, (0) is connected to the vacuum pump.

All parts of the apparatus must be capable of withstanding a vacuum of approxi-
mately 70 cm. and be perfectly air tight.

9 DETERMINATION.

Place 5-20 grams of soil as prepared under 2 (depending upon the carbonate con-
tent as indicated by qualitative 'examination) in the fiask (C), and connect up the
apparatus, but do not connect (A) to (B). Close the stop-cock (G) and the pnc'i-
cock (AT); open the pinch-cock (0) and exhaust the apparatus to a vacuum of ;.p-
proximately 70 cm. Close the pinch-cock (0). Connect the barium hydroxid
container by means of the pinch-cock (A) and rubber tube; open the pinclwok
(N) and allow sufficient barium hydroxid solution to flow into the Meyer absorption
apparatus to fill 3 or 4 of the small bulbs; close the pinch-cock (A) ; substitute the
barium hydroxid container by the carbon dioxid-free water container; open the
pinch-cock (N) and add sufficient carbon dioxid-free water to fill all the small bulbs
and most of the lower large bulb. Through the separatory funnel (B), add 83 cc. of
carbon dioxid-free water to the sample in the flask (C), avoiding the entrance of any
air, open the pinch-cock (0) and heat to boiling, protecting the flask from the direct
flame by a wire gauze with an asbestos center. Adjust the burner so that 2-3 min-
utes are required for the contents of the flask to reach boiling temperature and boil
until bubbles no longer pass through the Meyer absorption apparatus. Then
the pinch-cock (0), and run into the flask (C), avoiding the entrance of any air.
20 cc. of the dilute hydrochloric acid through the separatory funnel which is then
connected with the tube (A ) . This proportion of hydrochloric acid plus the 80 cc. of
water previously added, gives an acid (2tol00) for the decomposition of carbonates.
If the nature of the soil is such that a greater strength of acid is considered necessary,
an amount of acid (3 to 100) may be used for digesting the soil. Shake the Meyer
apparatus (E) gently, so that the liquid in the lower large bulb is brought into con-
tact with the gas therein, and open (O) carefully, but do not allow more than a few
bubbles to escape before shaking again. Repeat the operation several times until
bubbles no longer pass through the Meyer apparatus t,/'-') when (0) is opened. Leave
(0) open, and continue the boiling for about 25 minutes until carbon dioxid -
no longer evolved from the sample in the flask (C). Maintain a constant flow of
cold water through the condenser (D). Do not allow the boiling to become so violent
that liquid is drawn up into the condenser tube. If foaming is trouble-some, add a
drop of non-volatile oil through the separatory funnel (B). When the evolution of
carbon dioxid has ceased, close (O) and break t he vacuum by cautiously opening the
stop-cock (G) drawing in air through the tube (.1).

Disconnect the Meyer apparatus {E) and filter by the Cain method3 as follows:
Prepare a filter b}r covering a perforated porcelain plate within a carbon funnel with
a layer of asbestos, and a layer of ground quartz, both of which have previously been

II] SOILS 21

purified by digestion with hydrochloric acid and thorough washing with water.
The filter tube passes through a 1-holed rubber stopper which fits into a side arm
filtering flask. The side arm of this flask is connected to the suction pipe by a 2-way
stop-cock. In the top of the filter tube is fitted a 2-holed rubber stopper carrying
glass tubes bent at right angles. To these tubes are attached rubber tubing bearing
pinch-cocks. One of these rubber tubes terminates in a tube containing soda lime.
The other rubber tube is connected with one end of the Meyer apparatus. The
other end of the Meyer apparatus is attached to a bottle containing carbon
dioxid-free water by means of a well-washed rubber tube and a glass tube extending
to the bottom of the bottle. This glass tube passes through a 2-holed rubber stop-
per. In the other hole of the stopper is placed a tube containing soda lime. A
pinch-cock is placed on the tube joining the water bottle and the Meyer apparatus.
This cock is kept closed until the precipitate on the filter is ready for washing.
With the pinch-cock on the air outlet of the filter tube closed and the pinch-cock
from the filter tube to the Meyer apparatus open, apply gentle suction to the
filter flask until the contents of the Meyer apparatus have been transferred to the
filter. When necessary, the pinch-cock to the ai^ inletf of the filter tube is opened
to admit air behind the liquid in the Meyer apparatus. Open the pinch-cock be-
tween the wash-water bottle and the Meyer apparatus and open the stop-cock lead-
ing from the filter flask so as to maintain a gentle suction. By manipulation of
the Meyer apparatus the wash water comes in contact with all parts of the interior
of the apparatus, after which the water is sucked through the filter. After this
thorough washing admit air through the side opening of the stop-cock leading to the
filter flask.

Disconnect the apparatus, remove the filter pad with the barium carbonate from
the filter tube by means of a glass rod, place in a beaker and add a measured amount
of N/10 hydrochloric acid in excess, first rinsing the Meyer bulbs with a small amount,
carefully measured, of this acid and water. Titrate the excess of acid with N/10
sodium hydroxid, using methyl orange as indicator. Make a blank determination
under the same conditions and apply the necessary correction. From the amount of
N/10 hydrochloric acid required to neutralize the barium carbonate formed by the
carbon dioxid in the sample, calculate the quantity of inorganic carbon. One cc. of
N/10 acid corresponds to 0.0006 gram of carbon.

10

TOTAL NITROGEN.— OFFICIAL.

Place 7-14 grams of the soil, as prepared under 2, in a 300 cc. Kjeldahl digestion
flask with 30 cc, or more if necessary, of concentrated sulphuric acid and 0.7 gram of
mercuric oxid, or 0.65 gram of mercury. Mix immediately by shaking to prevent the
soil from adhering to the sides of the flask. Heat over a low flame, increase the heal
gradually, and rotate the flask frequently or shake if necessary to prevent the ((in-
tents from sticking to the bottom of the flask. When all the organic matter is de-
stroyed, continue the digestion for 1 hour. Oxidize the residue with potassium
permanganate, carefully adding small portions at a time to the hot liquid until, after
shaking, the liquid remains green or purple. After cooling, dilute the contents of
the flask with 100 cc. of water and transfer to a 700 cc. copper flask, using about 150 cc.
of water to wash out the digestion flask. Add an excess of strong alkali solution
containing potassium sulphid, connect the flask with a distilling apparatus, mix the
contents thoroughly and complete the determination as directed in I, 18.

22 METHODS OF ANALYSIS [Chap.

Strong Acid Digestion of the Soil
1 1 preparation of soil solution.-official.

Place an amount of soil, as prepared under 2 and equivalent to 10 grams on a mois-
ture-free basis, in a 200-300 cc. non-soluble glass Erlenmcyer flask to which is fitted, by
a ground joint or 1-holed rubber stopper, a reflux tube 20 inches or more in length.
Add lOOcc.of hydrochloric acid of constant boiling point (approximate sp. gr. 1.115,
1350 cc. of acid (sp. gr. 1.19), and 1000 cc. of water), and digest continuously
for 10 hours on a steam or water bath, shaking the flask every hour. Allow to settle,
and avoiding more than very small quantities of the sediment, decant the solution
into a porcelain dish or non-soluble glass beaker. Transfer by means of hot water
the insoluble residue to a filter, wash until free from chlorin and add the washings
to the original solution. Concentrate, oxidize the organic matter present in the
solution with a few drops of nitric acid and evaporate to dryness on a water bath.
Treat with hot water, add a few cc. of hydrochloric acid and again evaporate to com-
plete dryness. When the final evaporation is complete and the dish cooled, moisten
the residue with a few drops of strong hydrochloric acid. Add 10-20 cc. of water,
warm on the bath to secure complete solution of the soluble salts, filter and wash
until free from chlorin. Again evaporate the solution to dryness to render insoluble
any silica that may remain in solution, and treat as above. The filtrate constitutes
the acid extract freed of soluble silica, and is made up to a definite volume (250 or 500
cc.) and designated as A.

1 2 INSOLUBLE RESIDUE.— OFFICIAL.

Combine the filters and the main residue obtained in 11 in a small dish, dry, ignite
over a Bunsen flame for an hour or more, carefully at first, then completely over
a blast lamp to constant weight. Weigh and calculate as the insoluble residue.
This residue may be analyzed by the usual methods applicable to silicates or it may
be employed in the determination of total alkalies as described under 26. If it is
desired to determine the silica soluble in alkalies, treat a separate portion of the soil
as directed in 11, except that all filtrations must be made through the same hard-
ened filter, then, without igniting, wash the insoluble residue into a platinum dish,
dry at 100°C. and complete the determination as directed under III, 4 (a).

13 IRON, ALUMINIUM AND PHOSPHORIC ACID, COLLECTIVELY.— OFFICIAL.

(1) To an aliquot (50 or 100 cc, according to the probable amount of iron
present) of A, under 11, add ammonium hydroxid, drop by drop, until the precipi-
tate formed requires several seconds to dissolve, thus leaving the solution but faint-
ly acid. Heat nearly to the boiling point, and add ammonium hydroxid to precipi-
tate all of the iron, aluminium, etc. Boil in a covered beaker for about 1 minute,
remove, and if no ammonia is given off (detected by smelling) continue the addi-
tion, drop by drop, until ammonia can be detected. Do not allow the precipitate
to settle, but stir and pour on the filter. Wash immediately with hot water, using a
fine jet which is played around the edge of the precipitate, thus cutting it free
from the paper in order to produce rapid filtration. Wash the precipitate several
times, return it to the original beaker, dissolve with a few drops of hydrochloric
acid and warm. Rcprecipitate the iron, aluminium and phosphoric arid with
ammonium hydroxid as above and wash until free from chlorin. Designate the
filtrate as B.

Dry the filter and precipitate, remove the latter from the filter, ignite the filter
separately and add to its ash the precipitate. Then ignite to bright redness, cool

II] soils 23

in a desiccator and weigh as ferric oxid (Fe2Os), aluminium oxid (A1203), and phos-
phorus pentoxid (P205). Transfer this residue to a flask, digest with several cc.
of sulphuric acid (lto4), and heat to accelerate solution. When solution is complete
reduce with zinc and determine the ferrous iron by titration with a standard per-
manganate solution, and calculate to ferric oxid; or, (2) In lieu of the above, evapo-
rate 50 or 100 cc. of A, under 11 , with the addition of 10 cc. of su phuric acid until all
hydrochloric acid is expelled, dilute with water, reduce with zinc and determine the
ferrous iron by titration with a standard permanganate solution and calculate to
ferric oxid.

The weight of ferric oxid, plus that of the phosphorus pentoxid, determined
under 17 or 19, subtracted from the collective weight of ferric oxid, aluminium
oxid, and phosphorus pentoxid, gives the weight of the aluminium oxid.

14

MANGANESE.— OFFICIAL.

Concentrate B, under 13, to about 50 cc, cool, add bromin water until the solution
is colored, make alkaline with ammonium hydroxid, and heat to boiling in a covered
beaker; cool, and repeat the addition of bromin water, of ammonium hydroxid and
boil again. If a precipitate is obtained, slightly acidify the solution with acetic
acid, filter immediately, and wash with hot water. Dry the precipitate, ignite and
weigh as manganomanganic oxid (Mn304). Designate the filtrate, or if there is no
precipitate, the original solution, as C.

15 CALCIUM.— OFFICIAL.

Concentrate C, under 14, to about 50 cc, make slightly alkaline with ammonium
hydroxid, and add, while still hot, ammonium oxalate solution, drop by drop, slightly
in excess of complete precipitation, to convert the magnesium also into oxalate.
Heat to boiling, allow the precipitate to settle completely, decant the clear solution
on a filter, pour 15-20 cc. of hot water on the precipitate, and again decant the clear
solution on the filter. Dissolve the precipitate in the beaker with a few drops of
hydrochloric acid, add a little water, repeat the precipitation as above, and filler
through the same filter; transfer the precipitate to the filter and wash free from chlo-
rin with hot water; dry, ignite the precipitate over the blast lamp to constant weight,
and weigh as calcium oxid. Designate the filtrate and washings as D.

16

MAGNESIUM.— OFFICIAL.

Evaporate D, under 15, to dryness on the water bath and heat carefully to expel
ammonium salts. Treat the residue with 20-25 cc. of hot water and about 5 cc. of
hydrochloric acid, filter and wash. Concentrate to about 50 cc, cool, and add suffi-
cient disodium hydrogen phosphate solution to precipitate the magnesium; then
add gradually ammonium hydroxid, with constant stirring, until the solution is
distinctly alkaline. Determine if the precipitation is complete by the addition of
more of the disodium hydrogen phosphate solution. After 30 minutes. a<M gradually
10 cc. of strong ammonium hydroxid, cover to prevent the escape of ammonia, and
let stand in the cold. Filter after 12 hours, wash the precipitate free from chlorin,
using dilute ammonium hydroxid [I, 4 (d)]. dry the filter and precipitate and
fer the latter to a weighed porcelain crucible. Ignite the filter separately and add
its ash to the precipitate in the crucible. Burn at first al a moderate heat, then
ignite to whiteness or to a grayish white, weigh as magnesium pyrophosphate
(Mg2P207) and calculate to magnesium oxid (MgO).

24 METHODS OF ANALYSIS [Chap.

PHOSPHORIC ACID.

17 Gravimetric Method. — Official.

Concentrate 100-200 cc. of A, under 1 1 , to about 25-30 cc., neutralize with ammo-
nium hydroxid and add about 10 cc. additional. Dissolve the precipitate by theslow
addition of dilute nitric acid, stirring constantly and avoiding a large excess, add
gradually about 20 cc. of molybdate solution [I, 4 (a)], and allow to stand for 1 or 2
hours in a water bath at a temperature of 40°C. After an hour determine if the
precipitation is complete, as follows: Pipette about 5 cc. of the clear liquid into 5 cc.
of warm molybdate solution. If any precipitate is produced, return the test liquid
to the main portion, add more molybdate solution, and repeat the operation until
all the phosphoric acid is precipitated. Then allow to stand for several hours at
room temperature, preferably overnight. Filter off the ammonium phosphomolyb-
date, wash the precipitate thoroughly with cold water, dissolve with ammonium
hydroxid, and determine as magnesium pyrophosphate, as directed under I, 6 and
calculate to phosphorus pentoxid (P2O5).

Volumetric Method. — Tentative.

18 REAGENTS.

(a) Standard sodium or potassium hydroxid solution. — Strength such that 1 cc.
of this solution is equivalent to 0.0005 gram of phosphorus pentoxid (P2O5).

(b) Standard nitric acid solution. — Strength same as the standard alkali solution
described under (a) as determined by titration, using phenolphthalein as indicator.

19 DETERMINATION.

1 Proceed as in 17 until all the phosphoric acid is precipitated and then complete
the determination in the following manner:

Allow the solution containing the yellow precipitate to stand for at least 3 hours
at a temperature not above 40°C, filter on a small filter paper or on a Gooch crucible
and wash with cold water until the filtrate from 2 fillings of the filter yields a slight
pink color on the addition of phenolphthalein and 1 drop of the standard alkali.
Return the filter and precipitate to the same beaker used for precipitating the
phosphomolybdate, dissolve the yellow precipitate in the standard sodium or potas-
sium hydroxid solution, add a few drops of phenolphthalein and titrate the excess of
alkali with the standard acid. Calculate to phosphorus pentoxid (P2O5).

20 SULPHURIC ACID.— OFFICIAL.

Evaporate 100-200 cc. of A, under 11, nearly to dryness on a water bath to expel
the excess of acid, add 50 cc. of water, heat to boiling and add, drop by drop, 10^
barium chlorid solution until no further precipitation occurs. Continue the boiling
for about 5 minutes and allow to stand for 5 hours or longer in a warm place. Decant
the liquid on an ashless filter or tared Gooch, previously heated, treat the precipitate
with 15-20 cc. of boiling water, transfer to the filter and wash free from ehlorin with
boiling water. Dry the precipitate and filter, ignite, weigh as barium sulphate and
calculate to sulphur trioxid (S03).

POTASSIUM AND SODIUM.

21 Method I. —Official.

(1) Treat the filtrate from 20 with ammonium hydroxid exactly as in 13.
Evaporate the filtrate and washings to dryness, heat below redness until ammo-
nium salts are expelled, dissolve in hotwater, add 5 cc.of barium hydroxid solution.

II] soils 25

and heat to boiling; let settle for a few minutes, and determine if the precipitation
is complete by the addition of barium hydroxid solution to a little of the clear liquid.
When no further precipitate is produced, filter and wash thoroughly with hot water.
Heat the filtrate to boiling, add ammonium hydroxid and ammonium carbonate to
complete the precipitation of the barium, calcium, etc., let stand a short time on the
water bath, filter, and wash the precipitate thoroughly with hot water; evaporate
the filtrate and washings to dryness, expel ammonium salts by heating below red-
ness, treat with a little hot water, add a few drops of ammonium hydroxid, 1 or 2
drops of ammonium carbonate, and a few drops of ammonium oxalate; let stand
a few minutes on the water bath, set aside for a few hours, filter, evaporate to complete
dryness on the water bath, and heat to dull redness until all ammonium salts are
expelled and the residue is nearly or quite white. Dissolve in a minimum amount
of water, filter into a tared platinum dish, add a few drops of hydrochloric acid, evap-
orate to dryness on the water bath, heat to dull redness, cool in a desiccator, and
weigh as potassium and sodium chlorids. Repeat the heating until constant weight
is obtained. Dissolve in a small amount of water; if any residue remains, the sepa-
ration must be repeated until the residue of potassium and sodium chlorids is ent irel y
soluble. Dissolve the residue with water, add an excess of platinic chlorid solution
[1, 40 (b)], proceed as directed under 1, 45 and calculate to potassium oxid (K20) ; or,
(2) Instead of the foregoing, evaporate to dryness a fresh aliquot of A, under 11,
redissolve in water, treat directly with barium hydroxid solution, and from this point
proceed as directed above in (1).

22 Method II.— Tentative.

Proceed as in 21 through "let stand a short time on the water bath" (the point
at which the barium, calcium, etc., have been precipitated with ammonium hydroxid
and ammonium carbonate) and then proceed as follows:

Filter into a beaker, add 1 or 2 drops of hydrochloric acid and 1 cc. of ammonium
sulphate (75 grams to 1 liter), digest several hours on a water bath, and filter into a
tared platinum dish. Evaporate to dryness, heat to full redness, add 1 gram of
powdered ammonium carbonate; heat to expel excess of ammonium carbonate.
cool, and weigh the sulphates of sodium and potassium. Determine potassium as
directed under I, 42 (a) and calculate to potassium oxid (K20).

TOTAL PHOSPHORUS.

23 Magnesium Nitrate Method. — Official.

Place 5 grams of soil, as prepared under 2, in a porcelain dish. Moisten with 5-7
cc. of magnesium nitrate solution [I, 4 (e) ]. Dry on the water bath and burn off
the organic matter at low redness. Cool, moisten slightly with water, add 10 cc.of
concentrated hydrochloric acid, and digest 2 hours on the water bath, keeping the
dish covered with a watch glass and stirring 2 or 3 times during the digestion. Trans-
fer to a 250 cc. graduated flask, cool, fill to the mark, mix well, and pass through
a dry folded filter, pouring back on the filter until the filtrate becomes clear. Pipette
an aliquot corresponding to 2 or 4 grams of the soil, depending upon the amount
of phosphorus present, into a porcelain dish, evaporate to dryness, treat with hydro-
chloric acid and water, filter, and wash; the combined volume should not e:
40 cc. Make alkaline with ammonium hydroxid, and dissolve the precipitate by
the slow addition of concentrated nitric acid, using a slight excess. Add gradu-
ally, while shaking, 5-15 cc. of molybdate solution [I, 7 (a) ]. Keep the solution
at 40°-50°C. for an hour, let stand overnighl al room temperature, filter, and wash

well with cold water. Return the filter and precipitate to the same tlask and deter-
mine phosphorus volumel riftally, as directed under 19.

26 METHODS OF ANALYSIS [Chap.

24 Sodium Peroxid Method. — Official.

Place 10 grams of sodium peroxid in an iron or porcelain crucible and thoroughly
mix with 5 grams of the soil as prepared under 2. If the soil has very little organic
matter, add a little starch to hasten the action. Heat the mixture carefully by
applying the flame of a Bunsen burner directly upon \the surface of the charge and
the sides of the crucible until the action starts. Cover the crucible until the re-
action is over and keep at a low red heat for 15 minutes. Do not allow fusion to
take place. By means of a large funnel and a stream of hot water, wash the charge
into a beaker, acidify with hydrochloric acid and boil. Transfer to a 500 cc. gradu-
ated flask, cool and fill to the mark. If the action has taken place properly there
should be no undecomposed soil in the bottom of the flask. Allow the silica to
settle and draw off 200 cc. of the clear solution.

Precipitate the iron, aluminium, and phosphorus with ammonium hydroxid;
filter, wash several times with hot water, wash the precipitate back into the beaker
with l stream of hot water, and dissolve the precipitate in hot hydrochloric acid,
pouring the acid upon the filter to dissolve any precipitate adhering to it. Evapo-
rate the solution and washings to dryness on a water bath. Treat with dilute hy-
drochloric acid, heating if necessary, and remove the silica by filtration. Con-
centrate the filtrate and washings to about 10 cc, add 2 cc. of strong nitric acid,
and make alkaline with ammonium hydroxid. Add nitric acid very slowly and with
constant stirring until the solution is clear, avoiding an excess. Heat at 40°-50°C.
on a water bath, add 15 cc. of molybdate solution, [I, 7 (a) ], and maintain this tem-
perature for 1-2 hours. Let stand overnight, filter, and wash free from acid with
0.1% solution of ammonium nitrate, and, finally, once or twice with cold water.
Transfer the filter and precipitate to the same beaker and determine phosphorus
volumetrically as directed under 19.

25 TOTAL POTASSIUM.— OFFICIAL.

Decompose the soil by the J. L. Smith method4 as follows: Triturate gently
0.5 or 1 gram of the finely ground soil with 1 gram of dry ammonium chlorid in a
smooth mortar, then add 8 parts of calcium carbonate and mix intimately. Trans-
fer the mixture to a platinum crucible, rinsing the mortar with a little calcium car-
bonate. Heat the crucible gradually until fumes of ammonium salts no longer
appear, and continue until the lower three-fourths only of the crucible are brought
to a red heat. Maintain this temperature 40-60 minutes. The temperature should
be sufficient to keep the calcium chlorid formed by the reaction of ammonium chlo-
rid with calcium carbonate in a state of fusion. The mass, however, does not be-
come liquid since the fused calcium chlorid is absorbed by the large quantity of
calcium carbonate present. If the silicate is fused by the application of too strong
heat, disintegration of the mass at the end of the operation with water cannot be
effected. Moreover, too high a temperature causes volatilization of alkali chlorids.
The mass contracts in volume during the ignition, and is usually easily detached
from the crucible. Transfer the fused mass to a porcelain dish, thoroughly slake
with hot water, and grind thoroughly with an agate pestle. After washing 5 times
by decantation with hot water, transfer to a filter and wash well, 300 cc. of wash
water being sufficient. To the filtrate add 10 cc. of concentrated hydrochloric
acid, and evaporate nearly to dryness in a porcelain dish. Treat with hot water
and 2 cc. of hydrochloric acid and filter by means of suction through a small filter
into a 150 cc. Jena beaker. Concentrate the solution to 30 cc, add 1.5 cc. of platinic
chlorid solution [I, 40 (b) ], evaporate to a sirupy consistency, and add 15 cc of
2.25 N/1 acidulated alcohol (prepared by passing hydrochloric acid gas into a mix-

II] soils 27

ture of 2000 cc. of 95% alcohol and 152 cc. of hydrochloric acid, sp. gr. 1.20). Fil-
ter by means of suction through a small filter, wash with 80% alcohol, then with
ammonium chlorid solution [I, 40 (a) ], and finally with 80% alcohol. Dry the
precipitate on the filter and wash the precipitate with hot water into a weighed
platinum dish, using suction. Evaporate to dryness, heat in a drying oven for
an hour at 120°C, cool in a desiccator, weigh and calculate to potassium oxid (K20).

TOTAL ALKALIES. .

26 J. Lawrence Smith Method.* — Official.

(1) Proceed as directed under 25 to the point indicated by the phrase "300 cc. of
wash water being sufficient" (the point at which the ignited mass has been
disintegrated and thoroughly washed with water). The filtrate contains the sili-
cate alkalies in the form of chlorids together with calcium chlorid and hydrojrid.
Precipitate the calcium at once with ammonium carbonate solution; allow to settle,
decant the supernatant liquid into a porcelain (or platinum) dish, concentrate and
finally transfer the precipitate to the dish. When the volume is reduced to about
30 cc, add a little ammonium carbonate solution and ammonium hydroxid, heat
and filter into a porcelain (or platinum) dish, evaporate the filtrate to dryness on
a water bath and expel ammonium salts by ignition. Dissolve the residual alkali
chlorids in 3-5 cc. of water; a little black or dark brown flocculent matter usually
remains undissolved, while the solution may also contain traces of calcium. Add
2-3 drops of ammonium carbonate and ammonium hydroxid, warm gently, and fil-
ter through a very small filter into a weighed platinum vessel. Evaporate to dry-
ness on a water bath, heat the alkali chlorids to incipient fusion, cool, and weigh
as sodium and potassium chlorids; or,

(2) Determine, by the above method, the quantity of alkalies in the insoluble
residue, 12, and add that obtained under 21 or 22.

27 PHOSPHORUS SOLUBLE IN N/5 NITRIC ACID.— TENTATIVE.

Digest 10 grams of air-dried soil in a stoppered flask, with 100 cc. of N/5 nitric
acid, for exactly 5 hours in a water bath kept at a temperature of 40°C. Filter the
solution through a dry paper, cool to room temperature, and titrate 20 cc. of the
filtrate with standard potassium hydroxid solution (carbonate-free), using phenol-
phthalein as indicator. From the data thus secured calculate the number of cc.
of N/1 acid and of water to make exactly 1 or 2 liters of acid of N/5 strength after
allowing for the quantity neutralized by the amount of soil to be used in the fol-
lowing procedure:

Place 200 grams of the air-dried soil in a large, dry, glass-stoppered bottle and
add exactly 2000 cc. of N/5 nitric acid corrected for neutralization as above de-
scribed. With soils rich in available phosphoric acid, 100 grams of soil and 1000 cc.
of acid will be sufficient. Digest in a large water bath at a temperature of 40°C.
for exactly 5 hours, shaking thoroughly each half hour. At the end of the digest ion
shake the contents of the bottle well and pour quickly upon a large, dry, ribbed fil-
ter of 2 thicknesses of paper and of sufficient size to receive the entire contents of
the bottle. Collect the filtrate in a dry vessel, pouring back on the filter until the
filtrate becomes clear. Evaporate 1000 or 500 cc. of the filtrate, according to the
quantity of soil used, to dryness in a porcelain dish; add a few cc. of nitric acid to
oxidize organic matter, etc., moisten the residue with hydrochloric acid, digest
with water, and filter into a 500 cc. flask. Add a solution containing 1"> grams of
ammonium nitrate; then strong ammonium hydroxid until a permanent precipitate
forms, and then concentrated nitric acid slowly until the precipitate dissolves.

28 METHOD OF ANALYSIS

Dilute to about 100 cc, if less than that volume, place a thermometer in the flask,
and heat to 85°C. Add 75 cc. of recently prepared molybdate solution [I, 4 (a) ],
digest in a water bath at 80°C. for 15 minutes, with occasional shaking, remove from
the bath and allow to stand at least 10 minutes before filtering. Continue the de-
termination as directed under I, 6 and calculate to phosphorus pentoxid (P2O5).

28 CALCIUM CARBONATE REQUIRED.— TENTATIVE.

Place 100 grams of soil, as prepared under 2, in a 400 cc. wide-mouthed bottle,
add 250 cc. of N/1 potassium nitrate, stopper, and shake continuously for 3 hours
in a shaking machine, or every 5 minutes by hand. Let stand overnight. Draw
off 125 cc. of the clear, supernatant liquid, boil 10 minutes to expel carbon dioxid,
cool, and titrate with standard sodium hydroxid solution, 1 cc. of which is equiva-
lent to 4 mg. of calcium carbonate (0.001% on basis of the weight of soil used), using
phenolphthalein as indicator.

29 STATEMENT OF RESULTS.-OFFICIAL.

Calculate all results of soil analysis as per cent of the soil dried to constant weight
as under 3 and state in the following order:

Insoluble residue

Soluble silica

Manganomanganic oxid (Mn3O<0

Potassium oxid (K2O)

Sodium oxid (Na20)

Calcium oxid (CaO)

Magnesium oxid (MgO)

Ferric oxid (FeaOs)

Aluminium oxid (AI2O3)

Phosphorus pentoxid (P2O5)

Sulphur trioxid (S03)

Organic carbon

Inorganic carbon

Volatile matter . ,

Total nitrogen

Total phosphorus

Total potassium

Phosphorus soluble in N/5 acid

Calcium carbonate required

Total

BIBLIOGRAPHY

1 J. Am. Chem. Soc, 1904, 26: 294, 1640.

2 J. Agr. Sci., 3: (II), 155.

3 J. Ind. Eng. Chem., 1914, 6: 465.

4 Fresenius. Quantitative Chemical Analysis. Revised and amplified transla-
tion of the 6th German ed., 1906, 2: 1175; Crookes. Select Methods in Chemical
Analysis. 4th ed., 1905, p. 23; Wiley. Principles and Practice of Agricultural
Analysis. 1906. 1: 423; U. S. Geol. Sufv. Bull. 422, p. 171; Am. J. Sci.. 2nd
1871, 50: 269; Am. Chem., 1871, 1; Ann. Chem. Pharm., 1871, 159: 82.

III. PLANT CONSTITUENTS.

1 PREPARATION OF SAMPLE.— OFFICIAL.

Thoroughly cleanse the material from all foreign matter, especially from adhering
soil, air-dry, grind, and preserve the sample in tightly stoppered bottles.

2 PREPARATION OF ASH.— OFFICIAL.

Ignite 10-20 grams of the substance, in a flat-bottomed platinum dish in a muffle,
at a comparatively low temperature. Do not employ a full red heat because of the
danger of volatilizing alkali chlorids, etc. If rich in silica and alkalies, char the
material, treat with water to dissolve soluble salts, filter through an ashless filter,
dry the filter and paper and incinerate, add the filtrate to the incinerated residue,
evaporate to dryness and ignite at a low red heat. If rich in phosphates, e.g., seeds
and animal substances, char the material, dissolve soluble salts in dilute acetic
acid, filter through an ashless filter, wash with water, dry and incinerate the filter
and residue, add the filtrates to the incinerated residue, evaporate to dryness, and
ignite gently. While still warm, pulverize the whole of the ash as obtained above,
mix intimately and preserve in a tightly stoppered, dry bottle. If after incineration
the ash has absorbed moisture, dry thoroughly at low redness before bottling.

3 CARBON DIOXID.— OFFICIAL.

Determine carbon dioxid in a weighed portion of the ash prepared under 2. Lib-
erate the carbon dioxid by treatment with dilute hydrochloric acid in any of the
usual forms of apparatus, and determine the increase in weight of the potash
bulbs. The efficiency of the apparatus should be tested by blank determinations
conducted upon weighed portions of pure calcite.

4 CARBON, SAND AND SILICA.— OFFICIAL.

Transfer the residue from the carbon dioxid determination to a beaker or evapo-
rating dish; evaporate to dryness; pulverize and dry thoroughly to render the silica
insoluble. Moisten the dry residue with 5-10 cc. of hydrochloric acid, add about
50 cc. of water, allow to stand on the water bath for a few minutes, filter through
a hardened filter and wash thoroughly. Dilute the solution and washings to 250
cc. or other convenient volume. Designate as A .

Wash the residue from the filter into a platinum dish and boil for about 5 minutes
with approximately 20 cc. of a saturated solution of pure sodium carbonate, add a
few drops of pure sodium hydroxid solution, allow the solution to settle and decant
through a tared Gooch filter. Boil the residue in the dish with sodium carbonate
solution and decant as before. Repeat the process again, then transfer the residue
to the Gooch filter, wash thoroughly, first with hot water, then with a little dilute
hydrochloric acid, and finally with hot water until free from chlorin. Dry the filter
and contents to constant weight at 110°C. to determine the combined weight of
carbonaceous material and sand. Incinerate; the loss in weight represents the
carbonaceous material; the residue is sand. Confirm by microscopic examination.
D< termine the soluble silica as follows: (1) Combine the alkaline filtrate and wash-
ings, acidify with hydrochloric acid, evaporate to dryness and determine the silica

29

30 METHODS OF ANALYSIS [Chap.

in the usual way; or, (2) Treat a weighed portion of the ash, as prepared under 2,
with dilute hydrochloric acid. Evaporate to dryness; pulverize and dry thoroughly
to render the silica insoluble. Moisten the dry residue with 5-10 cc. of hydrochloric
acid, add about 50 cc. of water, allow to stand on the water bath for a few minutes,
filter on an ashless filter, wash, dry, ignite and weigh to determine the combined
weight of the silica and sand. Deduct the weight of the sand found above to obtain
that of the silica. The soluble silica cannot be separated from the residue after
ignition.

5 CARBON-FREE ASH.— OFFICIAL.

Subtract the weights of the carbon found in 4 and the carbon dioxid found in 3
from that of the total ash used in 3.

6 FERRIC AND ALUMINIUM OXIDS.— OFFICIAL.

(Applicable for plant materials other than seeds.)

Pipette an aliquot of A, under 4, corresponding to 0.5 gram of ash, into a 250 cc.
beaker. If ferrous iron is present, oxidize it by boiling with a few cc. of hydrogen
peroxid or of concentrated nitric acid. Cool, add ammonium hydroxid until a
precipitate begins to form, then nitric acid until just clear, and finally add 2-3 cc.
of concentrated nitric acid in excess. Add 25 cc. of 50% ammonium nitrate solution,
phosphate free, heat to 40°C, and add slowly, with constant shaking, a moderate
excess of molybdate solution [1, 4 (a)], and allow to stand for 1 or 2 hours at a tem-
perature not exceeding 40°C. After standing for an hour pipette 5 cc. of the clear
solution into an equal volume of warm molybdate solution. If a precipitate forme
in the test portion return it to the original solution and add more molybdate solu-
tion. Allow to stand at room temperature for several hours, preferably overnight.
Filter, wash with about 75 cc. of ammonium nitrate solution (2.5%, phosphate free,
and slightly acidified with nitric acid) and combine the filtrate and washings. Des-
ignate as B. Reserve the precipitate for the determination of phosphoric acid as
described under 1 1 .

Without concentrating solution^, cautiously neutralize with ammonium hydroxid,
add a very slight excess of the alkali, avoiding a temperature higher than 40CC, and
allow to stand at this temperature until the precipitate completely settles. Filter
the clear supernatant liquid, wash the precipitate a few times by decantation with
hot water before transferring to the filter, then wash 4 or 5 times on the filter. Dis-
solve the precipitate on the filter with hot nitric acid (1 to 5), wash and reprecipitate
as before. The combined filtrates and washings from the first and second precipi-
tations should not exceed 500 cc. and should not be concentrated by evaporation.
Designate as C and reserve for the determination of calcium and magnesium as
described under 8. The same filter may be used for the second filtration, ami the
volume of the solution for the reprecipitation need not exceed 100 cc. Before the
second filtration is made, a small quantity of ashless filter paper pulp should be
added in order to facilitate the washing and leave the precipitate finely divided
after the ignition, so that it can be easily fused with potassium hydrogen sulphate for
the iron determination. Dry and ignite the precipitate and weigh as ferric and
aluminium oxids.

The iron oxid is determined in the following manner: Fuse, in a platinum crucible,
the ignited precipitate with about 4 grams of fused potassium hydrogen sulp
This fusion takes but a few minutes and must not be continued beyond the time
actua ly needed. When completed the crucible is set aside and allowed to cool.
Add 5cc. of concentrated sulphuric acid and heat until copious fumes of sulphuric

Ill] PLANT CONSTITUENTS 31

acid are given off. Cool, transfer to a flask, add water, and digest till the solution is
clear. Reduce with zinc, cool, titrate with N/50 potassium permanganate and cal-
culate to ferric oxid.

If it is desired to use a larger amount of the sample for the iron determination,
evaporate a suitable aliquot of A, under 4, with sulphuric acid, reduce with zinc,
and titrate as above.

MANGANESE, CALCIUM AND MAGNESIUM.

(Applicable for plant materials other than seeds.)

7 Method I. — Official. -

To an aliquot of A, under 4, corresponding to 0.5-2 grams of ash, add a quantity
of pure ferric chlorid solution, more than sufficient to combine with the phosphoric
acid which may be present, and neutralize with ammonium hydroxid. Dissolve the
precipitate in a very slight excess of hydrochloric acid and add 1-2 grams of sodium
acetate. Boil for 1-2 minutes, filter at once, and wash with boiling water. Dissolve
the precipitate in hydrochloric acid and reprecipitate as above. Concentrate the
combined filtrates and washings to about 50 cc. and determine manganese, calcium
and magnesium as directed under II, 14, 15, and 16.

8 Method II. — Tentative.

Calcium. — Make alkaline with ammonium hydroxid the combined filtrates and
washings, C, under 6, and proceed as directed under II, 15. If the ignited calcium
oxid has a brown coloration, due to manganese, dissolve in dilute hydrochloric acid
and determine the manganese as directed below. Deduct the weight of mangano-
manganic oxid thus obtained from the weight of the impure calcium oxid.

Manganese. — Acidify the combined filtrates and washings from the calcium de-
termination and evaporate to dryness in a porcelain casserole. Expel the ammonium
salts by carefully heating the casserole from above, treat with a few cc. of hydro-
chloric acid and water, filter off molybdic acid, and wash the precipitate until it is
free from chlorin. Bring the filtrate to a volume of 100 cc, add 1-2 drops of bromin,
make alkaline with ammonium hydroxid and let stand for several minutes without
agitation. Filter off the precipitated manganese, wash, dry, ignite, and weigh the
precipitate as manganomanganic oxid. To this add the weight of the mangano-
manganic oxid found as an impurity in the calcium determination.

Magnesium. — Concentrate the alkaline filtrate from the manganese determination
to 75 cc. and determine magnesium as directed under II, 16.

PHOSPHORIC ACID.

9 Method I.— Official.

Determine phosphoric acid in an aliquot of A, under 4, corresponding to 0.2-1
gram of ash, as directed under I, 6 or 9.

10 Method II. —Official.

Determine phosphoric acid in the plant substance as directed under 1, 6, using suf-
ficient material to give 0.2-1 gram of ash in the aliquot of the solution employed.

1 1 Method III.— Official.

The phosphomolybdate precipitate obtained in 6 is used for the determination
of phosphoric acid as directed under I, 6, beginning with "Dissolve the precipitate

32 METHODS OF ANALYSIS [Chap.

on the filter with ammonium hydroxid, etc." or as under I, 9 (a), beginning with
"Wash with cold water until the filtrate from 2 fillings of the filter yields a pink
color, etc."

12 SULPHURIC ACID, SODIUM, AND POTASSIUM.— OFFICIAL.

Boil an aliquot of A, under 4, corresponding to 0.5-1 gram of ash, add barium
chlorid solution in small quantities until no further precipitate is formed, and pro-
ceed as directed under II, 20 and 21 .

13 CHLORIN.— OFFICIAL.

Determine as silver chlorid, either gravimetrically or by one of the standard
volumetric procedures (as the Volhard method given below), in a nitric acid or
aqueous solution of the ash.

Volhard Method.1

14 REAGENTS.

(a) N/10 silver nitrate.

(b) N/10 ammonium or potassium sulphocyanate.

(C) Ferric indicator. — Saturated solution of ferric alum.

(d) Nitric acid. — Free from lower oxids of nitrogen, secured by diluting the
usual pure acid with about 1/4 part of water, and boiling till perfectly colorless.

15 DETERMINATION.

Dissolve a weighed portion of the ash, prepared under 2, in nitric acid (1 to 10).
filter and wash with water. Add a known volume of the N/10 silver nitrate in slight
excess to the combined filtrate and washings. Stir well, filter, and wash the silver
chlorid precipitate thoroughly. To the filtrate and washings add 5 cc. of the ferric
indicator and a few cc. of the nitric acid. Titrate the excess of silver with the
N/10 sulphocyanate until a permanent light brown color appears. Calculate the
amount of chlorin.

1B POTASSIUM IN PLANTS.-OFFICIAL.

Determine potassium as directed under I, 42, using sufficient plant material to
yield 0.5-1 gram of ash in the aliquot of the solution used for the potassium determi-
nation.

SULPHUR IN PLANTS.

17 Peroxid Method. — Official.

Place 1.5-2.5 grams of material in a nickel crucible of about 100 cc. capacity and
add 5 grams of pure anhydrous sodium carbonate. Mix thoroughly, using a nickel or
platinum rod, and moisten with approximately 2 cc. of water. Add pure sodium
peroxid, approximately 0.5 gram at a time, thoroughly mixing the charge after each
addition. Continue adding the peroxid until the mixture becomes nearly dry and
quite granular, requiring usually about 5 grams of peroxid. Place the crucible over
a low alcohol or other sulphur-free flame and heat carefully with occasional stirring
until the contents are fused. (Should the material ignite, the determination is
worthless.) After fusion remove the crucible, allow to cool somewhat, and cover the
hardened mass with peroxid to a depth of about 0.5 cm. Heat gradually, and finally
with full flame until fusion again takes place, rotating the crucible from time to
time in order to bring any particles adhering to the sides into contact with the
oxidizing material. Continue the heating for 10 minutes after fusion is complete.

HI] PLANT CONSTITUENTS 33

Cool somewhat, place the warm crucible and contents in a 600 cc. beaker and care-
fully add about 100 cc. of water. After the initial violent action has ceased, wash
the material out of the crucible, make slightly acid with hydrochloric acid (adding
small portions at a time), transfer to a 500 cc. flask, cool, and make to volume.
Filter, and determine sulphates in 200 cc. of the filtrate as directed under II, 20.

18 CHLORIN IN PLANTS.— TENTATIVE.

Moisten 5 grams of the substance in a platinum dish with 20 cc. of a 5% solution of
sodium carbonate, evaporate to dryness, and ignite as thoroughly as possible at a
temperature not exceeding dull redness. Extract with hot water, filter and wash.
Return the residue to the platinum dish and ignite to an ash; dissolve in nitric acid,
add this solution to the water extract and determine chlorin as directed under 15.

BIBLIOGRAPHY.
1 Sutton. Volumetric Analysis. 10th ed., 1911, p. 145.

IV. WATERS.
POTABLE WATER.

TURBIDITY.— TENTATIVE.

1 REAGENTS.

(a) Standard turbidity solution. — Weigh out 1 gram of elutriated fuller's earth
previously dried and sifted through a 200 mesh sieve. Make up to a liter. If the
fuller's earth is of good quality and the proper degree of fineness, this stock solution
has a turbidity of 1000. Check the stock solution with a Jackson turbidimeter.

(b) Turbidity standards. — Prepared by dilution of (a).

2 DETERMINATION.

Determine the turbidity of the sample with a Jackson turbidimeter equipped
with either candle or electric light. If the turbidity is less than 100, which pro-
hibits the use of the turbidimeter, determine by direct comparison with turbidity
standards contained in bottles of clear white glass.

COLOR— TENTATIVE.

3 REAGENTS.

(a) Standard color solu'ion. — Dissolve 1.246 grams of potassium platinic chlorid
(PtCl42KCl) and 1 gram of crystallized cobalt chlorid (CoCl26H20) in a small quan-
tity of water, add 100 cc. of concentrated hydrochloric acid and make up to 1 liter
with water. This stock solution has a color of 500.

(b) Color standards. — Prepared by dilution of (a).

4 DETERMINATION.

Compare the color of the sample, freed from suspended matter, with color
standards in tubes of clear white glass.

5 ODOR.— TENTATIVE.

Shake the vessel containing the sample and note the odor. Heat a portion of the
sample just to boiling and note the odor.

3 TOTAL SOLIDS.— OFFICIAL.

Thoroughly shake the vessel containing the sample and pipette 100 cc. of the un-
filtered water into a weighed platinum dish. If the sample contains much suspended
matter, shake, pour rapidly into a 100 cc. measuring cylinder, and transfer without
delay to a weighed platinum dish; evaporate to dryness and heat to constant weight
at 105°C. In the case of highly mineralized waters it is advisable to weigh again
after drying at 180°C.

7 SOLIDS IN SOLUTION.— OFFICIAL.

Allow the sample to stand until all sediment lias settled, and filter if necessary
to secure a perfectly clear liquid. Occasiona ly a clear filtrate can only In- obtained
by the use of alumina cream but this should be avoided if possible. Evaporate 100-

35

36 METHODS OF ANALYSIS [Chap.

250 cc. to dryness in a weighed platinum dish. Heat to constant weight at 105°C.
In the case of highly mineralized waters it is advisable to weigh again after drying
at 180°C.

8 SUSPENDED MATTER.— OFFICIAL.

(1) The difference between the values for total solids and dissolved solids rep-
resents the suspended matter; or, (2) Determine the suspended matter directly by
filtering a suitable quantity of the water through a tared Gooch crucible, suitably
prepared, and weighing after drying at 105°C.

9 IGNITED RESIDUE.— OFFICIAL.

Ignite the residue from 6 at a low red heat until the ash is white or nearly so.
Note any odor or change in color produced during ignition. Record the weight
of the ignited residue and calculate the loss on ignition.

FREE AND ALBUMINOID AMMONIA.— OFFICIAL.

1 0 REAGENTS.

(a) Saturated solution of sodium carbonate.

(b) Ammonia-free water.

(C) Standard ammonium chlorid solution. — One cc. is equivalent to 0.01 mg. of
nitrogen in the form of ammonia (NH3).

(d) Nessler reagent. — Dissolve 50 grams of potassium iodid in a minimum quantity
of cold water. Add a saturated solution of mercuric chlorid until a slight perma-
nent precipitate is formed. Add 400 cc. of 50% solution of potassium hydroxid (or
an equivalent quantity of sodium hydroxid), dilute to 1 liter, allow to settle, and
decant.

(e) Alkaline potassium -permanganate solution. — Dissolve 200 grams of potassium
hydroxid and 8 grams of potassium permanganate in water and dilute to 1 liter.

11

DETERMINATION.

Connect a flask of about 1500 cc. capacity with an upright bulb condenser by
means of a rather large glass tube and a soft rubber stopper or a recently extracted
cork stopper. Place in the flask 5 cc. of the saturated solution of sodium carbonate
and 500 cc. of ammonia-free water. Distil into 50 cc. Nessler tubes until no further
traces of ammonia are indicated on the addition of 2 cc. of the Nessler reagent to
50 cc. of the distillate. Continue the distillation until the volume of the solution
in the flask has been reduced to about 200 cc. Cool slightly, add 500 cc. of the water
under examination, and distil, at the rate of 1 tubeful in 15 minutes, into 50 cc.
Nessler tubes until ammonia ceases to be given off (4 or 5 tubes are usually sufficient).
Add 2 cc. of the Nessler reagent to each tube and let stand 10 minutes. Freshly
prepare in a similar manner other tubes containing known amounts of the stand rd
ammonium chlorid, made up to 50 cc. with ammonia-free water, and compare the
nesslerized distillates with these. Report as milligrams per liter of nitrogen in the
form of free ammonia (NH,). Cool the flask and add 50 cc. of the alkaline perman-
ganate recently boiled. Distil, at the rate of 1 tubeful in 15 minutes, into 50 cc.
Nessler tubes until ammonia ceases to come off. Nesslerize and compare as in the
determination of free ammonia. Report as milligrams per liter of nitrogen in the
form of albuminoid ammonia (NHS).

IV] WATERS 37

NITROGEN IN THE FORM OF NITRITE.— OFFICIAL.

12 REAGENTS.

(a) Concentrated hydrochloric acid. — Sp. gr. 1.2.

(b) Suiphanilic acid solution. — Dissolve 1 gram of sulphanilic acid in 100 cc. of
hot water.

(C) Alpha-naphthylamin hydrochlorid solution. — Boil 0.5 gram of the salt with
100 cc. of water for 10 minutes at constant volume.

(d) Standard nitrite solution. — Dissolve 1.1 gram of silver nitrite in nitrite-free
water, precipitate the silver with sodium chlorid solution and dilute to 1 liter, mix
and allow to settle. Dilute 100 cc. to 1 liter and then 10 cc. of this solution to 1
liter, using in each case nitrite-free water. Each cc. of the last solution is equivalent
to 0.0001 mg. of nitrogen as nitrite.

1 3 DETERMINATION.

Place 100 cc. of the water in a 100 cc. Nessler tube and treat with 1 or 2 drops of
concentrated hydrochloric acid. * Add 1 cc. of the sulphanilic acid, 1 cc. of the alpha-
naphthylamin hydrochlorid, and thoroughly mix. Set aside for 30 minuteswith other
Nessler tubes containing known amounts of the standard nitrite made up to 100 cc.
with nitrite-free water, and treated with hydrochloric acid, sulphanilic acid, and
alpha-naphthylamin hydrochlorid in the manner just described. Determine the
amount of nitrite by comparing the depth of pink color in the known and unknown
solutions. Record as nitrogen in the form of nitrite.

NITROGEN IN THE FORM OF NITRATE.

Phenoldisulphonic Acid Method. — Official.
(For water of low chlorin content.)

14 REAGENTS.

(a) Phenoldisulphonic acid solution. — Dissolve 25 grams of pure white phenol in
150 cc. of concentrated sulphuric acid, add 75 cc. of fuming sulphuric acid (13-15%
S03) and heat at 100°C. for 2 hours.

(b) Standard nitrate solution. — Dissolve 0.722 gram of pure potassium nitrate in
1 liter of nitrate-free water. Evaporate 50 cc. of this solution to dryness in a porce-
lain dish; treat with 2 cc. of the phenoldisulphonic acid solution, rubbing with a glass
rod to insure intimate contact. Dilute to 500 cc. ; 1 cc. is equivalent to 0.01 mg. of ni-
trogen as nitrate. This solution is permanent. Standards for comparison are pre-
pared by adding ammonium hydroxid to measured volumes of it in 100 cc. Nessler
tubes.

(C) Standard silver sulphate solution. — Dissolve 4.3969 grams of silver sulphate,
free from nitrate, in 1 liter of water; 1 cc. is equivalent to 1 mg. of chlorin.
(d) Ammonium hydroxid. — Sp. gr. 0.90.

1 5 DETERMINATION.

Take 100 cc. of the sample, or an amount that will contain 0.05 mg. or less of
nitrogen as nitrate, and add standard silver sulphate, precipitating all but about
0.5 mg. of the chlorin. Heat to boiling, allow to settle, or add a little alumina cream,
filter, and wash with small amounts of hot water. Evaporate the filtrate to dryness
in a porcelain dish on the water bath; when cool, treat with 2 cc. of the phennldisul-
phonic acid solution as in 14 (b). Dilute with water and add slowly ammonium hy-

38 METHODS OF ANALYSIS [Chap.

droxid until the maximum color is developed. Transfer to a colorimetric cylinder,
filter if necessary, and compare with the standards in the usual manner. Record as
nitrogen in the form of nitrate.

Reduction Method. — Official.
(For water of high chlorin content.)

16 REAGENTS.

(a) Sodium or potassium hydroxid solution. — Dissolve 250 grams of the purest
hydroxid obtainable in 1250 cc. of water and boil down to 1 liter.

(b) Aluminium foil. — Use strips about 10 cm. long, weighing about 0.5 gram.

17 DETERMINATION.

Place 10 cc. of the sample in a 100 cc. test tube and dilute to exactly 50 cc. ; add 5 cc.
of the sodium hydroxid and a strip of the aluminium foil. Close the mouth of the
test tube with a rubber stopper carrying a U-shaped glass tube connected with a
second test tube containing about 50 cc. of ammonia-free water acidified with hydro-
chloric acid, which serves as a trap to catch any ammonia which might escape. Allow
to stand at room temperature for 12 hours or more until reduction is complete. Trans-
fer the contents of the first tube to a Kjeldahl flask and distil. Cool the distillates
and nesslerize as directed under 1 1 ; also nesslerize the solution in the trap. Record
as nitrogen in the form of nitrate.

CHLORIN— OFFICIAL.

18 REAGENTS.

(a) N /Z0 sulphuric acid.

(b) N/ SO sodium carbonate.

(C) Potassium chromate indicator. — Dissolve 5 grams of potassium chromate in
water, add a solution of silver nitrate until a slight permanent red precipitate is
produced, filter, and dilute to 100 cc.

(d ) Standard silver nitrate solution. — Dissolve 4.791 grams of silver nitrate in water
and dilute to 1 liter; 1 cc. is equivalent to 1 mg. of chlorin. Check by titration against
a standardized solution of sodium chlorid.

19 DETERMINATION.

To 100 cc. of the water add a few drops of phenolphthalein. If a red color appears,
titrate the carbonates thus indicated to bicarbonates with N 10 or N 20 sulphuric
acid. If the water is acid to methyl orange, add X/20 sodium carbonate to neutralize
the acidity. Add 1 cc. of the potassium chromate and titrate with the standard silver
nitrate. Correct for the amount of silver nitrate necessary to give in 100 cc. of chlorin-
free water with 1 cc. of the chromate, the shade obtained at the end of the titration
of the sample. Iodids and bromids are not usually found in interfering quantities
in potable water. However, if they are present make the equivalent correction.

If ch^orids are present in very small quantities concentrate 500 or 1000 cc. in a por-
celain dish to 100 cc, rub down the sides of the dish carefully, add 1 cc. of the indicator
and titrate as described above. If sufficient chlorids are present in 100 re. of the water
to consume more than 25 cc. of the standard silver nitrate, determine by precipita-
tion in nitric acid solution and weigh the silver chlorid.

IV] WATERS 39

OXYGEN REQUIRED.
Method I. — Official.

20 REAGENTS.

(a) Standard potassium permanganate solution. — Dissolve 0.3952 gram of potas-
sium permanganate in 1 liter of water; each cc. has 0.1 mg. of oxygen available for
oxidation.

(b) Standard oxalic acid solution. — Dissolve 0.7875 gram of crystallized oxalic acid
in 1 liter of water.

Determine the value of the oxalic acid in terms of the permanganate by boiling
10 cc. of the oxalic acid and 200 cc. of redistilled water (prepared by treating distilled
water with alkaline permanganate and distilling) with 10 cc. of sulphuric acid (1
to 3) and titrating, while still boiling, with the standard permanganate to the appear-
ance of a pink color.

21 DETERMINATION.

Add 10 cc. of sulphuric acid (1 to 3) to 200 cc. of the water in a porcelain dish and
heat to boiling. Add from a burette the standard permanganate until the water
is distinctly red and boil for 10 minutes, adding more of the standard permanganate
from time to time to maintain the red color. Add 10 cc. of the standard oxalic acid
and titrate back with the standard permanganate to a pink color. From the total
number of cc. used of the permanganate subtract the number of cc. equivalent to 10 cc.
of the oxalic acid. The result gives the number of cc. of the permanganate required
for 200 cc. of the water. Correct for sulphids, nitrites and ferrous salts, if present, by
subtracting the number of cc. of the standard permanganate absorbed by another
200 cc. portion of the sample when treated as above, digesting at room temperature
for 3 minutes.

Method II. (Schulze-Trommsdorf Method.1) — Tentative.
(To be used when the chlorin content of the sample is high.)

22

REAGENTS.

(a) 50% sodium hydroxid solution.

Other reagents and standard solutions are described under 20.

23

DETERMINATION.

Introduce 100 cc. of the water to be examined in a 300 cc. flask, add 0.5 cc. of the
sodium hydroxid and 10 cc. of the permanganate, boil for 10 minutes, allow to cool to
50°-60°C. and add 5 cc. of the dilute sulphuric acid and 10 cc. of the standard oxalic
acid. Assoonas the liquid has become perfectly colorless, and while constantly agita-
ting, cautiously add from a burette, drop by drop, the standard permanganate, until
the liquid acquires a faint permanent redness. The permanganate required to
effect this is the quantity required for the decomposition of the organic matter in
the 100 cc. of water.

If 100 cc. of the water require more than 4cc. of the permanganate for the o.cidation
of organic matter, a second determination must be made using more of the per-
manganate and a correspondingly larger quantity of the sodium hydroxid, as unde-
composed permanganate remaining after boiling must be at least twice as great as
the quantity decomposed.

40 METHODS OF ANALYSIS [Chap.

DISSOLVED OXYGEN.

Method I. (Winkler Method as Modified by Drown and Hazen.2) — Tentativ .
(When less than 0.1 mg. of nitrite nitrogen per liter is present.)

24 REAGENTS

(a) Manganous sulphate solution. — Dissolve 48 grams of manganous sulphate in
100 cc. of water.

(b) Sodium hydroxid-potassium iodid solution. — Dissolve 360 grams of sodium
hydroxid and 100 grams of potassium iodid in 1 liter of water.

(C) Sulphuric acid. — (Sp. gr. 1.4). Mix equal weights of concentrated sulphuric
acid and water.

(d) Standard sodium thiosulphate solution. — Dissolve 6.2 grams of recrystallized
sodium thiosulphate in 1 liter of water. This gives a N/40 solution, each cc. of which
is equivalent to 0.2 mg. of oxygen or 0.1395 cc. of oxygen at 0°C. and 760 mm. pressure.
This solution should be standardized occasionally against N/40 potassium dichromate.

(e) Starch indicator. — Mix about 2 grams of clean starch with cold water to a thin
paste; pour into about 200 cc. of boiling water. Boil for a few minutes. This solu-
tion should be freshly prepared.

25 COLLECTION OF SAMPLE.

Collect the sample in a carefully calibrated glass stoppered bottle, approximately
250 cc. capacity, by means of an apparatus designed to avoid the entrainment or
absorption of any oxygen from the atmosphere. Note the temperature.

26 DETERMINATION.

Add approximately 2 cc. of the manganous sulphate and 2 cc. of the sodium hydrox-
id-potassium iodid, delivering both of these solutions beneath the surface of the
liquid by means of a pipette. Insert the stopper and mix the contents of the bottle
by shaking. Allow the precipitate to settle. Remove the stopper; add about 2 cc.
of sulphuric acid and mix thoroughly. Rinse the contents of the bottle into a flask ;
titrate with N/40 sodium thiosulphate, using a few cc. of the starch indicator toward
the end of the titration. Do not add tin starch until the color has become a faint
yellow; titrate until the blue color disappears. Express the results in milligrams
per liter and in percentage of saturation.3 This latter determination is the ratio of
the amount of gas present to the maximum amount capable of being dissolved by
distilled water at the same temperature and pressure.

Method II. (Winkler Method as Modified by Rideal and Stewart.*) — Tentative.
(When more than 0.1 mg. of nitrite nitrogen ptr liter is present.)

27 REAGENTS.

(a) N/10 potassium permanganate.

(b) 2% potassium oxalate solution.
Other reagents are described under 24.

28 COLLECTION OF SAMPLE.

Proceed as directed under 25.

IV] WATERS 41

29 DETERMINATION.

Preliminary test. — Determine the amount of the permanganate required to o: -
dize the nitrite to nitrate by acidifying a preliminary sample of 50 cc. with 1 cc. of
the sulphuric acid and adding the permanganate until a slight pink color remains
after standing 10 minutes. Calculate the amount of the permanganate required for
a sample collected as described u' :r 25.

To the sample add 1 cc. of the sulphuric acid and about 0.1 cc. of the perman-
ganate in excess of the calculated amount required to oxidize the nitrite to nitrate.
If more than 10 cc. of the permanganate are required add an additional 1 cc. of the
sulphuric acid. Rotate the bottle and allow to stand for 10 minutes, after which
destroy any excess of the permanganate by adding from a pipette 0.5-1 cc. of the
oxalate. Insert the stopper and rotate as before. The color quickly disappears,
and when decolorized add approximately 2 cc. of the manganous sulphate and 2 cc.
of the sodium hydroxid-potassium iodid and proceed as in 26. Express the results
in milligrams per liter and percentage saturation.3

MINERAL WATER.

30 SPECIFIC GRAVITY.— TENTATIVE.

20°C

Determine specific gravity at z^: by means of a pycnometer.

31 SOLIDS IN SOLUTION.— OFFICIAL.
Determine as directed under 7.

32 IGNITED RESIDUE.— OFFICIAL.
Determine as directed under 9.

33 FREE AND ALBUMINOID AMMONIA.— OFFICIAL.
Determine as directed under 1 1 .

34 NITROGEN IN THE FORM OF NITRITE.— OFFICIAL.

Determine as directed under 13.

35 NITROGEN IN THE FORM IF NITRATE.— OFFICIAL.
Determine as directed under 15 or 17.

3g CHLORIN— OFFICIAL.

Determine as directed under 19.

37 HYDROGEN SULPHID.— TENTATIVE.

Place 0.5-2 cc. of N/100 iodin in a 500 cc. flask and add the water until the color
of the iodin disappears. Add 5 cc. of the starch indicator and then N/100 iodin until
a blue color appears. Fill the flask to the mark with water, noting the amount
added. Subtract the quantity of water, iodin solution, and the starch indicator
added, to determine the quantity of the water titrated. An excess of iodin is re-
quired to produce a blue color.' A correction is obtained by adding 5 cc. of the
starch indicator to 500 cc. of water and then adding N/100 iodin until the color
matches that of the sample under examination. Correct the original titration by
the amount of iodin used in the blank.

42 METHODS OF ANALYSIS [Chap.

38 FREE CARBON DIOXID.— TENTATIVE.

If the water reacts acid to phenolphthalein and alkaline to methyl orange, titrate
100 cc. with N/20 sodium carbonate (free from bicarbonate) until the solution is
neutral to phenolphthalein. The number of cc. used multiplied by 1.1 gives the
milligrams of free carbon dioxid in 100 cc. Express results in milligrams per liter.

39 CARBONIC AND BICARBONIC ACIDS.— OFFICIAL.

To 100 cc. of the water add a few drops of phenolphthalein and, if a pink color is
produced, titrate with N/20 crystallized potassium hydrogen sulphate or sulphuric
acid, adding a drop every 2 or 3 seconds, until the red color disappears. Multiply
the burette reading by the factor 3 which gives the milligrams of the carbonic acid
ion in 100 cc. To the colorless solution from this titration, or to the original solution
if no color is produced with phenolphthalein, add 1 or 2 drops of methyl orange; con-
tinue the titration without refilling the burette and note the total reading. If
carbonic acid is absent, multiply the total burette reading by the factor 3.05, which
gives the value of the bicarbonic acid ion in milligrams per 100 cc. If carbonic acid is
present, multiply the reading with phenolphthalein by 2 and subtract from the total
reading of the burette. Multiply the difference by 3.05, which gives the bicarbonic
acid ion in milligrams per 100 cc. Express results in milligrams per liter.

Silica, Iron, Aluminium, Calcium, Strontium and Magnesium.

40 SrLICA— OFFICIAL.

Make a preliminary examination, using 100-250 cc. of water to determine the
approximate quantity of calcium and magnesium present, in order to ascertain
the quantity of water to be evaporated for the final analysis.

Evaporate a quantity, usually 1-5 liters, of the water sufficient to yield 0.1-0.6
gram of calcium oxid or 0.1-1 gram of magnesium pyrophosphate. Acidify the
water with hydrochloric acid and evaporate on the water bath to dryness in a plati-
num dish; continue the drying for about an hour. Thoroughly moisten the residue
with 5-15 cc. of hydrochloric acid (1 to 1). Allow to stand 10-15 minutes and add
sufficient water to bring the soluble salts into solution. Heat on the steam bath
until solution of the salts is effected. Filter to remove most of the silica and wash
thoroughly with hot water. Evaporate the filtrate to dryness; treat with 5-10 cc.
of the hydrochloric acid and sufficient water as above. Heat, filter, and wash
thoroughly with hot water. Designate the filtrate as A . Transfer the 2 residues to
a platinum crucible, ignite, heat over a blast lamp and weigh. Moisten the contents
of the crucible with a few drops of water. Add a few drops of concentrated sulphuric
acid and a few cc. of hydrofluoric acid and evaporate on the water bath under a good
hood. Repeat the treatment if all the silica is not volatilized. Dry carefully on a
hot plate, ignite, heat over a blast lamp, and weigh. The difference between the
two weights is the weight of the silica. The residue in the crucible consists of alumin-
ium and iron oxids. The weight of this residue is added to that of the total alumin-
ium and iron oxids obtained in 41 . (If the above residue weighs more than 0.5 mg.,
barium sulphate may be found here when barium is present in the water. If so,
make the necessary correction and add to the weight of the total iron and aluminium
oxids in 41 .)

41 IRON AND ALUMINIUM.— OFFICIAL.

Concentrate A, under 40, to about 200 cc; while still hot, add ammonium hydroxid
slowly with constant stirring until alkaline to methyl orange. Boil, filter, and wash
2 or 3 times with hot water. Dissolve the precipitate in hot hydrochloric acid.

IV] WATERS 43

Dilute to approximately 25 cc, boil, and again precipitate with ammonium hydroxid;
filter, wash thoroughly with hot water, dry, ignite, and weigh as iron and aluminium
oxids. (In the presence of phosphoric acid, the weight of this residue must be cor-
rected for the phosphorus pentoxid equivalent to the phosphoric acid found in 51 ,
making due allowance for the difference in the volumes of the water used for these
determinations.) Designate the filtrate as B.

IRON.

42 Colorimetric Method.

(If the amount of iron is less than 1 mg.)

Fuse in a platinum crucible the ignited precipitate of iron and aluminium
oxids with fused potassium hydrogen sulphate, dissolve in water, and precipitate the
iron and aluminium with ammonium hydroxid. Dissolve the precipitate on the
filter paper in hydrochloric and nitric acids, dilute the solution, add ammonium
sulphocyanate solution (1 to 20) and compare the color developed with that of
calibrated color disks, or standards containing known amounts of iron.

43 Volumetric Method.

Fuse in a platinum crucible the residue of iron and aluminium oxids with fused
potassium hydrogen sulphate. This fusion takes but a few minutes and must not
be continued beyond the time actually needed. When completed, the crucible
is set aside and allowed to cool. Add dilute sulphuric acid and heat the crucible
until the fused mass is dissolved. Evaporate on the water bath as far as possible;
then heat gradually until copious fumes of sulphuric acid are given off. Dissolve
in water and allow to stand on the water bath. Cool, transfer to an Erlenmeyer
flask, and make up to such a volume that the solution does not contain more than
2.5% of free sulphuric acid. Pass hydrogen sulphid through the solution to reduce
the iron and precipitate any platinum contaminating the residue from the fusion.
(Zinc may be used instead of hydrogen sulphid for reducing the iron.) Filter, wash
and again pass hydrogen sulphid through the solution to be certain that all the iron
is reduced. Expel the hydrogen sulphid by boiling, at the same time passing a
current of carbon dioxid through the solution; test the escaping gas with lead acetate
paper to ascertain the complete removal of hydrogen sulphid. When hydrogen
sulphid has been removed discontinue boiling and let the flask cool somewhat with-
out discontinuing the current of carbon dioxid. Titrate the reduced iron with a
standard permanganate solution (1 cc. equivalent to 1 mg. of Fe) and calculate as
iron.

44 ALUMINIUM.— OFFICIAL.

In the absence of phosphates, subtract from the weight of iron and aluminium
oxids, under 41 , the iron, under 42 or 43, calculated to oxid, to obtain the weight of
aluminium oxid. Calculate to aluminium.

45 CALCIUM.-OFFICIAL.

Concentrate B, under 41 , to 150-200 cc. and to this solution, containing not more
than 0.6 gram of calcium, calculated as calcium oxid, or 1 gram of magnesium, cal-
culated . magnesium pyrophosphate, add 1-2 grams of oxalic acid and sufficient
hydrochloric acid to clear the solution. Heat to boiling and neutralize with ammo-
nium hydroxid, stirring constantly. Add ammonium hydroxid in slight excess and
allow to stand 3 hours in a warm place. Filter off the supernatant liquid and wash

44 METHODS OF ANALYSIS [Chap.

the precipitate once or twice by decantation with 1% ammonium oxalate solution.
Dissolve the precipitate in hydrochloric acid, dilute to 100-200 cc, add a little
oxalic acid, and precipitate as above. After standing 3 hours, filter, wash with the
ammonium oxalate solution as above, dry, ignite, heat over a blast lamp, and weigh
as calcium and strontium oxids. Subtract from this weight, the weight of strontium
oxid equivalent to the strontium under 46. The difference is the weight of calcium
oxid. Calculate to calcium. Designate the filtrate and washings as C.

As a check on the calcium oxid, evaporate to dryness the filtrate from the stron-
tium nitrate under 46, beginning with "Filter, wash with ether-alcohol mixture,
etc.," dissolve the calcium nitrate in water, precipitate as oxalate, filter, wash,
ignite, and weigh as calcium oxid.

46 STRONTIUM.— TENTATIVE.

Dissolve the oxids under 45 in dilute nitric acid and test with the spectroscope for
strontium. If strontium is present, transfer the nitric acid solution to a small
Erlenmeyer flask. Evaporate nearly to dryness over a low flame and heat in an
air bath at 150°-160°C. for 1 or 2 hours after the water is evaporated. Break up the
dried material with a stirring rod, add 10-15 cc. of a mixture of equal parts of absolute
alcohol and ether to dissolve the calcium nitrate. Cork the flask and allow to stand
with frequent shaking for 2 hours or longer. Decant the solution through a 5.5 cm.
filter, preserving the filtrate. Wash the residue several times by decantation with
small portions of ether-alcohol solution. Dry the residue and the filter paper and
wash the filter paper repeatedly with small portions of hot water, collecting the
filtrate in the flask containing the main portion of the strontium nitrate residue.
Add 1 or 2 drops of dilute nitric acid, evaporate, dry, pulverize, and treat with
10-15 cc. of ether-alcohol mixture as above. Cork the flask and let stand about 12
hours with occasional shaking. Filter, wash with ether-alcohol mixture until a few
drops of the filtrate evaporated on a watch glass leave practically no residue. Dry
the paper and precipitate. Dissolve the strontium nitrate in a few cc. of hot water.
Add a few drops of sulphuric acid, then a volume of alcohol equal to the volume of
the solution and allow to stand 12 hours. Filter, ignite, weigh as strontium sulphate
and calculate to strontium. Test spectroscopically for absence of calcium.

47 MAGNESIUM.— OFFICIAL.

Concentrate C, under 45, to about 200 cc. ; add 2-3 grams of diammonium hydrogen
phosphate and sufficient hydrochloric acid to clear the solution when the ammonium
phosphate is all dissolved; disodium hydrogen phosphate or sodium ammonium
hydrogen phosphate may be used instead of the diammonium hydrogen phosphate.
When cold, make slightly alkaline with ammonium hydroxid, stirring constantly.
Add 1-2 cc. excess of ammonium hydroxid and allow to stand about 12 hours. Filter
off the supernatant liquid and wash 3 or 4 times by decantation with a solution of
2.5% ammonium hydroxid. Dissolve the precipitate in hydrochloric acid, dilute to
about 150 cc, add a little diammonium hydrogen phosphate and precipitate with
ammonium hydroxid as before. Allow to stand 6-12 hours, filter, wash free from
chlorin, ignite, heat over a blast lamp, and weigh as magnesium pyrophosphate.
(Cf. II, 16). Calculate to magnesium.

Sulphuric Acid, Sodium, Potassium and Lithium.

48 sulphuric acid.— official.

Make a preliminary examination, using 100-250 cc. of the water to determine the
approximate quantity of sulphates. The alkali salts present can be approximated

IV] WATERS 45

by calculating the amount of sodium necessary to combine with the excess of acids
(hydrochloric, sulphuric, and bicarbonic) over the calcium and magnesium.

Take a quantity, usually 1-5 liters, of the water sufficient to yield not more than
1 gram of barium sulphate and not more than 0.5 gram of mixed chlorids. Acidify
with hydrochloric acid, evaporate to dryness in a platinum dish and remove silica
by 2 evaporations as under 40, using not more than 2 cc. of hydrochloric acid (1 to 1)
for the final solution. Combine the filtrate and washings from the silica determi-
nations, and concentrate to about 150-200 cc. Heat to boiling and precipitate with
slight excess of 10% barium chlorid solution, added very slowly and with constant
stirring. Cover and allow to stand on the steam bath about 12 hours. Filter, wash
thoroughly the precipitate of barium sulphate with hot water, dry, ignite over a
Bunsen burner, and weigh.

If the content of sulphate in the sample is unusually large proceed as far as the
concentration of the silica filtrates as directed above. Add 50 cc. of concentrated
hydrochloric acid, heat to boiling and precipitate with barium chlorid solution as
before. Evaporate to dryness, wash the precipitate repeatedly by decantation and
filter. Complete the washing of the precipitate; ignite and weigh. Calculate to
the sulphuric acid ion. Designate the filtrate as E.

49 SODIUM, POTASSIUM AND LITHIUM.— OFFICIAL.

Evaporate to dryness!?, under48, in a platinum dish and ignite the residue to faint
redness to remove all traces of ammonium salts. Dissolve the residue in the dish
in about 200 cc. of water and precipitate with milk of lime or a solution of barium
hydroxid. Boil, allow to stand 30 minutes, and filter off the insoluble magnesium
hydroxid. Thoroughly wash the precipitate with hot water and combine the filtrate
and washings. If the precipitate of magnesium is large, it is advisable to dissolve
in a small amount of hydrochloric acid, evaporate to dryness, take up with water,
and precipitate as before. Concentrate the 2 filtrates and washings to 200-250 cc.
Add ammonium hydroxid and sufficient ammonium carbonate solution to precipi-
tate the calcium and barium. Allow to stand on a steam bath 1-2 hours. Filter off
the supernatant liquid, dissolve the precipitate in hydrochloric acid, reprecipitate as
above, and wash thoroughly with hot water. Evaporate the combined filtrates and
washings to dryness and drive off the ammonium salts by gentle heat. Treat the
residue with water; filter through a small filter, using as little wash water as possible;
evaporate to a small volume and again precipitate with 1 or 2 drops of ammonium
hydroxid and 2 or 3 drops of ammonium carbonate and oxalate. If any precipitate
appears (which is usually not the case) filter and repeat the process. Evaporate the
filtrate to dryness and drive off all ammonium salts by heating in platinum to faint
redness. Treat the residue with a little water; filter into a small platinum dish;
add a few drops of hydrochloric acid and evaporate to dryness. Dry in an oven,
heat to faint redness, cool in a desiccator, and weigh the combined chlorids of potas-
sium, sodium, and lithium. Repeat the heating to constant weight, (i). Dissolve
the mixed chlorids in hot water; filter, and wash. Return the filter paper and residue
to the dish, dry, ignite, and weigh, (y). The difference between (x) and (y) is the
weight of the mixed chlorids.

The determination of lithium is then made according to the method of Gooch.1
Transfer the combined chlorids to a 50-100 cc. Erlenmeyer flask and evaporate the
solution nearly, but not "uite, to dryness. Add about 30 cc. of redistilled amy]
alcohol. Connect the flask, the stopper of which carries a thermometer, using a
condenser if desired, to avoid the escape of the irritating vapor of the amy] alcohol,
and boil until the temperature rises approximately to the boiling point of amyl alco-

46 METHODS OF ANALYSIS [Chap.

hol (130°C.) to remove the water. Cool slightly and add a drop of hydrochloric acid
to convert small amounts of lithium hydroxid to lithium chlorid. Connect with the
condenser and repeat the boiling until the temperature reaches the boiling point of
amyl alcohol to again drive off the water. The content of the flask at this time is
usually 15-20 cc. Filter through a small paper or a Gooch crucible into a graduated
cylinder and note the exact quantity of the filtrate, which determines the subsequent
correction. Wash the precipitate with small quantities of amyl alcohol. Evapo-
rate the filtrates and washings in a small platinum dish to dryness on the steam bath,
dissolve the residue in water, and add a few drops of sulphuric acid. Evaporate on
a steam bath and expel the excess of sulphuric acid by heating gently over a Bunsen
burner until the carbonaceous matter is completely burned off, repeating the addi-
tion of a few drops of sulphuric acid if necessary. Cool and weigh the dish and
contents, (x). Dissolve in a small quantity of hot water, filter through a small
filter, wash and return filter to dish; ignite and weigh, (y). The difference between
(x) and (y) is the weight of impure lithium sulphate.

The purity of the lithium sulphate should be tested by adding small amounts of
ammonium phosphate solution and ammonium hydroxid, which will precipitate any
magnesium previously present in the lithium sulphate. Any precipitate appearing
after standing overnight should be collected on a small filter, ignited, weighed as
magnesium pyrophosphate, calculated to sulphate and subtracted from the weight
of the impure lithium sulphate.

From this weight subtract 0.00113 gram of sodium and potassium sulphates for every
10 cc. of amyl alcohol filtrates, exclusive of the amyl alcohol used in washing the
residue, on account of the solubility of sodium and potassium chlorids in amyl alco-
hol. Calculate to lithium from the corrected weight of lithium sulphate.

Dissolve the mixed chlorids from the flask and filter with hot water, evaporate
to dryness, ignite gently to remove amyl alcohol, filter, and thoroughly wash; con-
centrate the filtrates and washings to 25-50 cc. Transfer to a porcelain dish, add
sufficient platinic chlorid solution [I, 40 (b)] to convert sodium and potassium to
their respective double chlorids and evaporate to dryness. Treat the residue
with 80% alcohol, filter, -and wash until the excess of platinic chlorid and sodium
platinic chlorid has been removed. Dry the filter and precipitate, dissolve the
residue in hot water, and transfer to a weighed platinum dish. Evaporate on the
steam bath, dry for 30 minutes in the oven at 100°C. and weigh as potassium platinic
chlorid; calculate to potassium chlorid. To the weight of potassium chlorid add
0.00051 gram for every 10 cc. of amyl alcohol used in the extraction of the lithium
chlorid, which corrects for the solubility of the potassium chlorid in amyl alcohol.
Calculate to potassium.'

The weight of sodium chlorrd is found by subtracting the combined corrected
weights of lithium chlorid and potassium chlorid from the total weight of the 3
chlorids. Calculate the sodium chlorid to sodium.

PHOSPHORIC ACID.— OFFICIAL.

50 REAGENTS.

The reagents used are described under I, 7.

51 DETERMINATION.

Treat 500 cc. of the water, or a larger amount if necessary, with about 10 cc. of
concentrated nitric acid and evaporate in a porcelain dish nearly to dryness to drive
off hydrochloric acid. Treat the residue with water and filter, if necessary. Add
ammonium hydroxid to alkalinity and then just enough nitric acid to restore acidity.

IV] WATERS 47

Add some solid ammonium nitrate and heat in the water bath at a temperature of
45°-50°C. Add the molybdate solution and keep at the above temperature for 30
minutes. The yellow precipitate formed at this point appears generally only in
traces; if more than traces are present, filter and wash with cold water until entirely
free from nitric and molybdic acids. Transfer the precipitate and filter to a beaker,
add a little water, and beat the paper and contents to a pulp. Dissolve the yellow
precipitate in a small amount of the standard potassium hydroxid; add phenolphthal-
ein and titrate with the standard acid. From the data so obtained calculate the
phosphoric acid ions in the water to milligrams per liter.

52 Manganese, Iodin, Bromin, arsenic and Boric Acid.

Evaporate large quantities of water to dryness, after the addition of small amounts
of solid sodium carbonate. Boil the residue thus obtained with water, transfer to
a filter, and wash thoroughly with hot water. Make the alkaline filtrate up to a
definite volume.

MANGANESE.— OFFICIAL.

53 REAGENTS.

(a) Dilute nitric acid (1 to 1).

(b) 0.2% silver nitrate solution.
(C) Ammonium persulphate.

(d) Standard manganous sulphate solution. — Dissolve 0.2877 gram of pure potas-
sium permanganate in a small amount of water, add an excess of sulphuric acid,
reduce carefully with oxalic acid and make up to 1 liter. One cc. of this solution is
equivalent to 0.1 mg. of manganese.

54 DETERMINATION.

Dissolve the insoluble residue under 52 in an excess of the dilute nitric acid, evap-
orate to dryness, treat with water, add about 1 cc. of strong nitric acid and a little
of the silver nitrate. If a precipitate of silver chlorid appears, add more of the
silver nitrate until all the chlorin is precipitated. Add an excess of about 10 cc. of
the silver nitrate for each mg. of manganese present in the sample. Filter, add
1 gram of ammonium persulphate to the filtrate, and place the beaker or flask con-
taining the solution on the steam bath until a p;nk color develops (usually about 20
minutes). Compare the color developed with standards similarly prepared by treat-
ing solutions containing known amounts of the standard manganous sulphate with
nitric acid, silver nitrate, and ammonium persulphate.

IODIN AND BROMIN.-TENTATIVE.

55 REAGENTS.

(a) 10% sodixim hydroxid solution.

(b) Sulphuric acid (1 to 5).

(C) 2% potassium or sodium nitrite solution.

(d) Carbon disxdphid. — Freshly purified by distillation.

(e) Chlorin water. — Saturated and freshly prepared.

56 DETERMINATION.

Evaporate to dryness an aliquot of the alkaline filtrate under 52, add 2-3 cc. of
water to dissolve the residue and enough 95% alcohol to make the percentage of
alcohol about 90. This precipitates the chlorids. Heat to boiling, filter and repeat
the preceding solution and precipitation once or twice. Add 2 or 3 drops of the

48 METHODS OF ANALYSE [Chap.

sodium hydroxid to the combined alcoholic filtrates and evaporate to dryness. Dis-
solve this last residue in 2-3 cc. of water and repeat as above described the precipi-
tation with alcohol, heating, and filtering. Add a drop of the sodium hydroxid to
this alcoholic filtrate and evaporate to dryness. Dissolve this residue in a little
we iv, acit *y with the sulphuric acid, using 3 or 4 drops in excess, and transfer to
a small flask. Add 4 drops of the potassium nitrite and about 5 cc. of the carbon
disulphid. Shake until all the iodin is extracted, filter off the acid solution from the
carbon disulphid, retaining the latter in the flask. Wash the flask, filter and con-
tents with cold water and transfer the carbon disulphid (containing the iodin in
solution) to a Nessler tube, using approximately 5 cc. of the carbon disulphid. In
washing the filter make the contents of the tube up to definite volume, usually 12-15
cc, and compare the color with that of other tubee containing known amounts of
iodin dissolved in carbon disulphid. Prepare these standard tubes by treating
measured quantities of a solution of known potassium iodid content as described
above. Transfer the sample and standards, from which the iodin has been removed,
severally to small flasks. To the standards add definite measured quantities of a
bromid solution of known strength, and to each of the flasks containing sample and
standards add 5 cc. of purified carbon disulphid. Add the saturated chlorin water.
1 cc. at a time, shaking after each addition until all the bromin is set free. (Avoid
a large excess of chlorin, since a bromo-chlorid may be formed which spoils the color
reaction.) Filter off the water solution from the carbon disulphid through a mois-
tened filter, wash the contents of the filter 2 or 3 times with water, and then transfer
to a Nessler tube by means of about 1 cc. of carbon disulphid. Repeat this extrac-
tion of the filtrate twice, using 3 cc. of carbon disulphid each time. The combined
carbon disulphid extracts usually amount to 11.5-12 cc. Add enough carbon di-
sulphid to the tubes to bring them to a definite volume, usually 12-15 cc, and com-
pare the sample with the standards. In some cases when using this method near its
upper limit the amounts of carbon disulphid recommended do not extract all the
bromin. In these cases, make 1 or 2 extra extractions with carbon disulphid, trans-
fer the extracts to another tube, and compare the color with some of the lower
standards and add the readings thus obtained to the others.

Results closely approximating the true values for iodin and bromin can be ob-
tained on most samples by omitting the extractions with alcohol given above and
by comparing the color of the carbon disulphid solutions directly in the extraction
flasks, thus shortening the method.

ARSENIC— OFFICIAL.
57 REAGENTS.

(a) Zinc, arsenic-free.

(b) Sulphuric acid (1 to 5), arsenic-free.

(C) Standard arsenious oxid solution. — Dissolve 0.0132 gram of pure arsenious
oxid in 100 cc. of water containing about 50 mg. of sodium carbonate. One cc. of
this solution is equivalent to 0.1 mg. of As.

58

DETERMINATION".

Evaporate to dryness an aliquot of the alkaline filtrate under 52. Acidify with
the sulphuric acid and subject to the action of the zinc and the sulphuric acid in a
Marsh-Berzelius apparatus. Compare the mirror obtained with a mirror prepared
from an arsenious oxid solution of known strength. Calculate to the arsenic acid
ion.

IV] WATERS 49

BORIC ACID.— OFFICIAL.

(Glassware containing boron must not be used in this determination.)

59 DETERMINATION. .• |

Qualitative test. — Evaporate to dryness a part of the alkaline filtrate under 52,
treat with 1-2 cc. of water, and slightly acidify with dilute hydrochloric acid (1 to 1) .
Add about 25 cc. of 95% alcohol, boil, filter, and repeat the extraction of the residue.
Make the filtrate slightly alkaline with sodium hydroxid solution and evaporate
to dryness. Add a little water, slightly acidify with dilute hydrochloric acid, and
place a strip of turmeric paper in the liquid. Evaporate to dryness on the steam
bath and continue the heating until the turmeric paper is dry. If boric acid is
present the turmeric paper takes on a cherry-red color. As a confirmatory test,
apply a drop of dilute ammonium hydroxid to the reddened paper, and a dark
olive color will be due to boric acid.

Quantitative test. — It is not usually necessary to determine boric acid quantita-
tively. However, if it is necessary, the Gooch method6 is used.

60 METHOD OF REPORTING RESULTS— TENTATIVE.

Report the bases and acids as positive and negative ions in milligrams per liter,
except in the case of silica, which report as such without considering how much is
present as the silicic acid ion and how much as free silica. Report iron and alumin-
ium together when present in unimportant quantities, and in calculations consider
it as iron. When iron and aluminium are present in larger quantities make the
separation and report each separately.

In calculating the hypothetical combinations of acid and basic ions join sodium
to nitrous, nitric, metaboric and arsenic acids; potassium to iodin and bromin;
calcium to phosphoric acid. Assign the residual basic ions in the following order;
ammonium, lithium, potassium, sodium, magnesium, calcium, strontium, manganese,
iron and aluminium — to the residual acid ions in the following order: Chlorin,
sulphuric acid ion, carbonic acid ion, and bicarbonic acid ion. In case the bicar-
bonic acid ion is not present in a sufficient quantity to join with all the calcium,
the residual calcium is joined to silica to form calcium silicate, and manganese, iron,
and aluminium are calculated to the oxids Mn304, Fe2Os, and AI2O3, respectively.

INDUSTRIAL WATER.

61 SOLIDS IN SOLUTION.— OFFICIAL.

Determine as directed under 7.

62 CHLORIN— OFFICIAL.
Determine as directed under 19.

63 COMBINED CARBONIC AND BICARBONIC ACIDS.— OFFICIAL.
Determine as directed under 39.

64 NITRATES.-OFFICIAL.
Determine as directed under 15 or 17.

65 SILICA.— OFFICIAL.

Determine as directed under 40. Generally one evaporation with hydrochloric
acid for removal of silica is sufficient.

50 METHODS OF ANALYSIS [Chap.

65 IRON AND ALUMINIUM.— OFFICIAL.

Determine as directed under 41.

67 CALCIUM.— OFFICIAL.

If no phosphoric acid is present, concentrate the filtrate from the determination
of iron and precipitate with ammonium hydroxid and oxalate as directed under 45.
Usually one precipitation is sufficient.

68 MAGNESIUM.— OFFICIAL.
Determine as directed under 47.

69 SULPHURIC ACID AND ALKALIES.— OFFICIAL.

Follow the methods described under 48 and 49. Generally, however, for tech-
nical purposes it is sufficiently accurate to determine the acids and the bases,
except sodium and potassium, and then to calculate the excess of acid over basic
ions to the sodium salt, and state the alkali thus found as sodium and potassium by
difference.

70 TEMPORARY HARDNESS.7— TENTATIVE.

The difference between the alkalinity after boiling, 74, and the alkalinity before
boiling, 72, is the temporary hardness in parts per million of calcium carbonate.

ALKALINITY— Before Boiling.

71 REAGENTS.

(a) N/50 sulphuric acid.

(b) Erythrosin indicator. — Dissolve 0.1 gram of the sodium salt in 1 liter of water.
(C) Chloroform. — Neutral to erythrosin.

72

DETERMINATION.

Measure 100 cc. of the water into a 250 cc. white, glass-stoppered bottle, add 2.5 cc.
of the erythrosin and 5 cc. of the chloroforn idd N /50 sulphuric acid in small quanti-
ties, shaking the bottle vigorously after each addition of the acid. The rose color
gradually disappears and is finally discharged by 1 or 2 drops of the acid. A white
paper held back of the bottle facilitates the detection of the end point. Multiply
the number of cc. of X/50 sulphuric acid used by 10 to obtain the number of parts per
million of alkalinity in terms of calcium carbonate.

ALKALINITY— After Boiling.

73

REAGENTS.

Described under 71 .

74

DETERMINATION.

Boil 100 cc. of the water in a porcelain dish gently for 30 minutes. Cool, transfer
to a 100 cc. volumetric flask and fill to the mark with recently boiled and cooled
water. Filter through a dry paper and determine the alkalinity of the filtrate as
directed under 72, making the proper calculation for the aliquot employed and cal-
culating in terms of calcium carbonate the parts per million of alkalinity after
boiling.

IV] %'-<*-_ WATERS 51

75

(a) Soda reagent. — Prepare a if/ 10 alkali solution, using equal parts of sodium
hydroxid and sodium carbonate. Standardize the solution by titration against
N/20 sulphuric acid, using erythrosin as indicator.

"WATERS

TOTAL HA

NESS.3— TENTATIVE

tEAGENTS.

76

DETERMINATION.

Add sufficient N/20 sulphuric acid to 200 cc. of the sample to neutralize the alkalin-
ity, the amount required for this purpose being calculated from the results obtained
as directed under 72. Concentrate to 100 cc, add 25 cc. of the soda reagent, and
again boil down to 100 cc, using a porcelain, silver, or platinum dish. Cool, rinse
into a 200 cc volumetric flask and dilute to 200 cc. with freshly boiled and cooled
water. Filter through a dry paper, reject the first 50 cc. of the filtrate, and titrate
100 cc. of the filtrate, using N/20 sulphuric acid and chloroform with erythrosin as
indicator, as directed under 72. Calculate the total hardness by the following
formula: H = 12.5 (S-2N) in which

H = total hardness expressed as parts per million of calcium carbonate.

S = number of cc. of N/20 sulphuric acid equivalent to the 25 cc. of the soda
reagent used.

N = number of cc. of N/20 sulphuric acid used in titrating back the excesB of
the soda reagent.

77 PERMANENT OR NON-CARBONATE HARDNESS.— TENTATIVE.

The difference between the alkalinity before boiling 72 and the total hardness 76
is the permanent or non-carbonate hardness expressed as parts per million of cal-
cium carbonate.

IRRIGATING WATER.

78 GENERAL METHODS.— OFFICIAL.

Determine the solids in solution, chlorin, carbonic and bicarbonic acids, sulphuric
acid, calcium and magnesium as directed under 7, 19, 39, 48, 45, and 47 respec-
tively. To make the hypothetical con ination, calculate calcium and magnesium
to the acid ions in the following order: bicarbonic, sulphuric and chlorin. Then
calculate the remaining acid ions, including carbonic, to the corresponding salts of
sodium.

BLACK ALKALI.— OFFICIAL.

79 REAGENTS.

(a) N/50 sodium carbonate. — One cc of this solution is equivalent to 0.00106
gram of sodium carbonate.

(b) N/50 sulphuric acid. — One cc. of this solution is equivalent to 0.0010 gram of
calcium carbonate or 0.00136 gram of calcium sulphate.

(C) Erythrosin indicator. — Dissolve 0.25 gram of the sodium salt in 1 liter of water.
(d) Chloroform. — Neutral to erythrosin.

80

DETERMINATION.

Transfer 200 cc. of the water to a platinum or silver dish, add 50-100 cc. of N/50
sodium carbonate, according to the amount of soluble salts of calcium and magnesium
present, and evaporate to dryness. Rub up the residue with carbon dioxid-free

wafer.

52 METHODS OF ANALYSIS

For this purpose distilled water should be vigorously boiled until approximately
one third of the original volume is evaporaf d, then cooled and stoppered. An
ordinary laboratory wash bottle should not bv lsed to transfer the residue, as the
carbon dioxid from the breath of the operator 'is sufficient to vitiate the results.

Transfer to a 100 cc. graduated flask, make up to the mark, shake thoroughly, and
allow to stand until clear (12-15 hours). Remove 50 cc. of the clear, supernatant
liquid, equivalent to one half of the original quantity of water and sodium carbonate
added, and transfer to a stoppered titrating bottle, of 250 cc. capacity, of clear glass
without any tinge of pink. Add 5 cc. of the chloroform and 1 cc. of the erythrosin
and titrate with the standard acid until the color disappears. Shake the solution
vigorously after each addition of the acid; the chloroform produces a milky appear-
ance which makes the reading of the end point sharp and certain.

(1) If less sulphuric acid is required than is equivalent to one half of the sodium
carbonate added, due to some of the sodium carbonate reacting with soluble salts of
calcium and magnesium, the solution originally contained no black alkali in excess
but rather an excess of the so-called permanent or non-carbonate hardness. It is
customary to express the hardness in terms of calcium carbonate or calcium sul-
phate. With irrigating waters the latter form is to be preferred. Therefore, the
difference between the number of cc. of the sulphuric acid required and one half of
the number of cc. of the sodium carbonate added multiplied by the factor 0.00136
gives the equivalent of calcium sulphate in 100 cc. of the water.

(2) If more sulphuric acid is required than that equivalent to one half of the
sodium carbonate added, black alkali was originally present in the solution and the
difference in cc. multiplied by the factor 0.00106 gives the black alkali in terms of
sodium carbonate in 100 cc. of water.

BIBLIOGRAPHY.

1 Fresenius. Quantitative Chemical Analysis. Revised and amplified trans-
lation of the 6th German ed., 1906, 2: 204.

2 Ber., 1888, 21: 2843; Rept. Mass. State Board of Health, 1890, 2: 722.

8 J. Am. Chem. Soc, 1911, 33: 362; Standard Methods of Water Analysis. Am.
Pub. H. Assoc, 2nd ed., 1912, pp. 61 and 62.

4 Sutton. Volumetric Analysis, 10th ed., p. 303; Analvst, 1901, 26: 141.
6 Am. Chem. J. 1887, 9: 33; U. S. Geol. Surv. Bull. 422, 175.

6 Am. Chem. J. 1887, 9 : 23.

7 Standard Methods of Water Analysis. Am. Pub. H. Assoc, 2nd ed., 1912, pp.
36 and 37.

8 Ibid, pp. 40 and 41.

V. TANNING MATERIALS.— TENTATIVE.
EXTRACTS.

1 PREPARATION OF SOLUTION.

(a) Solid extracts. — Grind solid extracts in a large porcelain mortar, so that the
material will pass through a 10 mesh sieve, mix thoroughly and weigh out a quantity
containing 3.75-4.25 grams of tannin. This should be done as rapidly as possible to
avoid change in moisture content. Pour into 100 cc. of water at 85°C, place on a
steam bath and stir until a homogeneous solution is obtained. Transfer to a 1 liter
flask with 800 cc. of water at 85°C. Cool rapidly to 20°C. and make up to 1 liter.

(b) Fluid extracts. — Allow fluid extracts to come to room temperature and mix
thoroughly. Weigh out rapidly a quantity containing 3.75-4.25 grams of tannin.
Dissolve by washing into a 1 liter flask with 900 cc. of water at 85°C. Cool rapidly
to 20°C. and make up to 1 liter at 20°C.

After the preparation of the solutions, proceed at once with the analysis.

2 TOTAL SOLIDS.

Thoroughly mix the prepared solution, pipette at once 100 cc. into a tared flat-
bottomed glass dish, 2f— 3 inches in diameter, and (1) evaporate and dry for 16 hours
in a combined evaporator and dryer1 at 98°-100°C. ; or, (2) after evaporating on the
steam bath, dry for 12 hours on the bottom of a water oven at 98°-100°C. Remove
immediately to desiccators containing sulphuric acid (place no more than 2 dishes in
1 desiccator) and weigh rapidly when cooled. Calculate the percentage of total
solids.

SOLUBLE SOLIDS.

3 PREPARATION OF FILTER.

The kaolin used should be neutral to phenolphthalein and should not yield more
than 1 mg. of soluble solids per 100 cc. of filtrate of a 1% suspension after an hour's
digestion at 20°C. Dry on a water bath and preserve in a tightly stoppered bottle.

Add about 75 cc. of the solution, as prepared under 1 , to 1 gram of the kaolin in a
beaker. Stir and pour immediately into a single, 15 cm. No. 590, S. & S. folded
filter. Return the filtrate to the paper when approximately 25 cc. have run through,
repeat the operation for an hour, thus transferring all the kaolin to the paper. At
the end of an hour, discard the solution on the filter by siphoning it off, disturbing
the kaolin as little as possible.

4 DETERMINATION.

Bring about 150 cc. of the original solution, as prepared under 1 , to exactly 20°C.
Fill the filter, prepared as under 3, with this solution and discard the filtrate until
it runs through clear. Keep the filter full, the temperature of the filtering solution
at 20°-25°C, and the funnel and receiving vessel covered. Pipette at once 100 cc. of
the clear filtrate into a tared dish, evaporate and dry as directed under 2. Calculate
the percentage of soluble solids.

53

54 METHODS OF ANALYSIS [Chap.

5 INSOLUBLE SOLIDS.

The difference between the percentage of the total solids and the percentage of
soluble solids is the percentage of the substance insoluble in water at 20°-25°C.

NONTANNINS.

6 REAGENTS.

Hide powder. — This should be of woolly texture, well delimed, and 10 grams of the
water-free powder should require 12-13 cc. of N/10 sodium hydroxid to neutralize it.

Calculate the amount of air-dry hide powder which will be required for the number
of determinations to be made, on a basis of 13 grams of air-dry hide powder for
each determination. Increase this calculated amount by 35 grams of dry hide
powder to provide a sufficient amount for all the determinations.

Thoroughly digest the total amount of hide powder with 10 times its weight of
water. Then for each gram of the hide powder, so digested, add 1 cc. of 3% chrome
alum solution; and either agitate frequently for several hours and let stand overnight
or agitate in some form of mechanical shaker for an hour. Transfer to a strong
linen filter and squeeze thoroughly. Remove from the filter and digest for 15 minutes
with a quantity of water equivalent to 15 times the weight of the dry hide powder
employed. Filter and squeeze to approximately 73% of water, using a press if
necessary. Very strong pressure is required to reduce the water content below
70%. Repeat the digestion and filtration 3 times. Determine moisture in 20 grams
of the squeezed hide powder as directed under 2.

7 DETERMINATION.

Place 46 grams of the wet hide powder in a suitable container of about 300 cc.
capacity, add 200 cc. of the tanning solution, as prepared under 1, and shake for 10
minutes in a mechanical shaker. Squeeze immediately through linen, add 2 grams
of kaolin, as used under 3, to the filtrate which contains the nontannins, stir, and
filter through a single, folded 18.5 cm. filter paper (No. IF. Swedish, preferred),
refiltering until the filtrate is clear. The filtrate should give no precipitate with a
gelatin-salt solution (1% gelatin and 10% salt). Pipette 100 cc. of the filtrate into
a tared dish and evaporate as directed under 2. Correct the weight of the nontannin
residue for the dilution caused by the water retained in the wet hide powder. Cal-
culate the percentage of nontannins.

8 TANNIN.

The difference between the percentage of the soluble solids and the percentage
of nontannins is the percentage of tannin.

DETECTION OF SULPHITE-CELLULOSE.

9 REAGENTS.

Sulphite-cellulose solution. — Dissolve 0.5 gram of the total solids, derived from
sulphite-cellulose, in 1 liter of water and add sufficient tanning material, free from
sulphite-cellulose, to give a concentration of 3.75-4.25 grams of tannin per liter.

10 DETERMINATION.

Place 5 cc. of the tanning solution, prepared as under 1 , in a test tube; add 0.5 cc.
of ani'.in and shake v, ell; then add 2 cc. of concentrated hydrochloric acid and mix
again. Compare the precipitate formed with that produced when the above sul-

V] TANNING MATERIALS 55

phite-cellulose solution is similarly treated. Sulphite-cellulose is held to be present,
in the predetermined absence of the synthetic tanning material, Neradol-D, if the
precipitates are approximately equivalent in amount.

LIQUORS.

11 PREPARATION OF SOLUTION.

Dilute the liquor with water at room temperature to contain approximately 0.7
gram of solids in 100 cc. of solution. If the liquor does not give a proper solution
with water at room temperature, it may be diluted with water at 80°C, and then
cooled rapidly to 20°C.

12 TOTAL SOLIDS.
Proceed as directed under 2.

13 SOLUBLE SOLIDS.
Proceed as directed under 4.

14 NONTANNINS.

Proceed as directed under 7, using the amount of wet chromed hide powder which
will give the ratio between the tannin and hide powder shown in the following table:

TANNIN RANGE PER
100 CC.

DRY HIDE POWDER
PER 200 CC.

gram

0.35—0.45
0.25—0.35
0.15—0.25
0.00—0.15

grams

9.0—11.0
6.5— 9.0
4.0— 6.5
0.0— 4.0

TOTAL ACIDITY.
15 REAGENTS.

(a) Hematin solution. — Digest 0.5 gram of hematin in 100 cc. of cold neutral 95%
alcohol.

(b) Gelatin solution. — Dissolve 10 grams of gelatin in hot water, cool, add 25 cc. of
95% alcohol and dilute. If the gelatin solution is acid or alkaline, neutralize with
N/10 sodium hydroxid or N/10 acetic acid, respectively, using hematin solution as
indicator and make up to 1 liter.

(C) Kaolin. — Digest with dilute hydrochloric acid; wash and dry as under 3.
(d ) N/10 sodium hydroxid.

16

DETERMINATION.

Add 25 cc. of the gelatin solution to 25 cc. of the tanning liquor in a stoppered
cylinder, dilute with water to 250 cc, add 15 grams of the kaolin and shake vigorously.
Allow to settle for at least 15 minutes, remove 30 cc. of the supernatant liquid, dilute
with 50 cc. of water and titrate with N/10 sodium hydroxid, using the hematin solu-
tion as indicator. Each cc. of N/10 sodium hydroxid is equivalent to 0.2% acid,
calculated as acetic, in the liquor.

[Chap.

5fi METHODS OF ANALYSIS

RAW AND SPENT MATERIALS.
(Under raw materials are included woods, barks, leaves, etc.)

■J 7 MOISTURE IN SAMPLE AS RECEIVED.

Cut or break up large pieces and mix the sample rapidly to avoid change in mois-
ture content. Dry as directed under 2. a suitable weighed quantity, dependent upon
the physical condition and moisture content of the sample.

18 PREPARATION OF SAMPLE.

Dry the remainder of the sample at a temperature not above 60°C. and grind to
pass through a 20 mesh sieve.

19 MOISTURE IN PREPARED SAMPLE.

Take 10 grams of the sample prepared in 18, dry as directed under 2, and calculate
all results to an "as received", "air dry", or "moisture free" basis as '-•sired.

20 EXTRACTION.

FIG. 4. METAL EXTRACTOR \JS\ ~^H EXTRACTING TANNING MATERIALS.

(For spent materials approximate the :s as closely as possible.)

Place a quantity of the dried sample, containing 3..^ 25 grams of tannin, n a
beaker and wet thoroughly with hot water. Place a perforated porcelain plate in
a tin-lined copper extractor of the general form shown in Fig. 4, and on the plate
place a layer of cotton and wet thoroughly with water. Connect the extractor with
an 800 cc. Erlenmeyer flask (G), open the stock-cock (E) and close the outlets (C)
and (D). Pour into the extractor the material to be extracted, washing it into the
extractor with hot water. Return the percolate through the extractor until it is
practically clear. Place a layer of cotton on top of the material. Close the stop-
cock (E), connect with an 800 cc. Erlenmeyer flask containing about 650 cc. of water,
connect (D) by a delivery tube with a liter graduated collecting flask, return the
totA percolate to the extractor and connect by means of the metal cap (B) with a
block tin condenser (A) in such a way that the condensate will drip upon the layer
of cotton. Boil the water in the flask, and collect 400-500 cc. of percolate from the.
side tube (D). Open the stop-cock (E) and close the side tube (D), add water to the
flask (GO, if necessary, until it contains about 200 cc. Continue Nie extraction with
water at steam heat, allowing the percolate to run back into t.ie boiling flask. He-

V] TANNING MATERIALS 57

peat with 2 successive portions (150-250 cc. each) of water for a total of 14 hours,
heating at such a rate that approximately 330 cc. of water will be condensed per
hour. Combine all the extracts in the graduated liter flask in which the first per-
colate was received. Heat to 80°C, cool, and make up to the mark.

21 ANALYSIS OF THE EXTRACT.

Proceed as directed under 2—8, inclusive. If more dilute solutions than the
directions specify are employed in the determination of nontannins, the amount of
hide powder used is reduced, as directed under 14.

BIBLIOGRAPHY.
1 J. Am. Leather Chem. Assoc, 1906, 1: 32.

.1 01 f" *

Dissol-- iA

'

VI. LEATHERS.— TENTATIVE.
VEGETABLE TANNED LEATHER.

1 PREPARATION OF SAMPLE.

Grind the sample, without undue heating, and pass through a 10 mesh sieve. The
ground sample must not contain hard lumps. Plane heavily greased leathers (con-
taining more than 20 % fat) into very thin shavings. Spread out the prepared sample
and allow it to return to atmospheric moisture condition; mix thoroughly, and
place in tightly covered containers.

2 MOISTURE.

Place 10 grams of the sample, as prepared under 1 , in a tared, wide, shallow, weigh-
ing bottle (or a similar dish which can be covered tightly), and dry in a water oven
for 15 hours at 98M00°C. Cover the weighing bottle, cool in a desi cator containing
sulphuric acid, and weigh. The moisture present in the leather as received maj be
determined by cutting it quickly into small pieces and drying without grinding as
directed above.

3 TOTAL ASH.

Incinerate slowly 5 grams of the sample, as prepared under 1 , at a dull red heat.
If difficulty is experienced in burning off the carbon, leach the residue with hot
water, filter on an ashless filter, dry and ignite the filter and residue, add the filtrate,
evaporate to dryness and ignite. Cool in a desiccator containing sulphuric acid and
weigh.

The ash may be examined for acids and bases by any suitable method. Alurj in-
ium, magnesium, sodium, barium, calcium and lead are the bases, and hydrochloric
and sulphuric acids are the acids which it may be necessary to determine.

4 INSOLUBLE ASH.

Incinerate slowly the residue from the extraction of water-soluble material, ob-
taine I in 6 or 7, until all the carbon is burned off, cool in a desiccator containing
sulphuric acid and weigh.

5 FATS.

Place, without packing, 15 grams of the leather, as prepared under 1 , in a Soxhlet
or Johnson extractor with a layer of fat-free cotton above and below the sample.
Extract 8-10 hours with petroleum ether distilling between 50° and 80°C. Heavily
greased leathers (containing 15% or more fat) will require the maximum time. Re-
move the receiving flask, evaporate the petroleum ether on the st am bath and dry
the fat residue for 3 hours in a water oven at 98°-100°C., cool in a desiccator a:id
weigh. Repeat the drying in the water oven for periods of 1-1 \ hours, cooling and
weighing as before, until no further loss in weight occurs. Retain the leather
residue from the fat extraction for the extraction of water-soluble material in 6 or 7.

EXTRACTION OF WATER-SOLUBLE MATERIAL.

6 Method I.

Evaporate the petroleum ether from the fat-free leather, obtained under 5, and
moisten thoroughly with from 100-150 cc. of water. Place a layer of cotton in the

59

60 METHODS OF ANALYSIS [Chap.

bottom of a Soxhlet extractor designed for making extractions at temperatures be-
low 100°C.

An extractor of this kind is furnished with a water jacket surrounding that por-
tion of the apparatus containing the sample but does not enclose the side tube which
carries the hot vapors to the condenser.

Transfer the moistened fat-free leather to the extractor, and cover this with
another layer of cotton to avoid siphoning off solid particles. Maintain the tempera-
ture of the jacket surrounding the Soxhlet at 50°C. (1) Pour 200 cc. of water (in-
cluding that used in moistening the leather) into the Soxhlet and allow it to siphon
into the flask below, then heat and extract for an hour. Remove the flame and trans-
fer the extract to a liter graduated flask. Then add water and continue the ex-
traction as directed below, removing and transferring the extract to the liter
flask before each fresh addition of water.

(2) Add 175 cc. of water and extract for 2 hours.

(3) Add 175 cc. of water and extract for 3 hours.

(4) Add 175 cc. of water and extract for 4 hours.

(5) Add 175 cc. of water and extract for 4 hours.

Transfer the last portion of the extract to the graduated flask. This gives 14
hours' extraction and an extract which does not exceed 1 liter in volume. Dilute to 1
liter at room temperature and mix thoroughly.

7 Method II.

(This method is the same in principle as the official method of the American Leather

Chemists Association.1)

Digest overnight 30 grams of the fat-free leather, obtained under 5, in approxi-
mately 200 cc. of water. Transfer the leather and extract to a percolator. Continue
the extraction by percolating with water at 50°C. Collect 2 liters of percolate,
regulating the flow of water at such a rate that 2 liters will be collected in 3 hours.
Dilute to volume at room temperature and mix thoroughly.

To the extract, prepared according to 6 or 7, add a few drops of toluol to prevent
fermentation of sugars, and reserve for the determination of glucose, total solids,
soluble solids, and nontannins.

GLUCOSE.

8 PREPARATION OF SOLUTION.

To 200 cc. of the leather extract, as prepared under 6 or 7, add 25 cc. of a saturated
solution of normal lead acetate, mix thoroughly, and filter at once through a dry,
plaited paper, returning the first portions of the filtrate to the filter until the fil-
trate becomes clear. Keep the containers and the funnel covered during these opera-
tions. Without waiting for the entire filtrate to run through add 10-12 prams
of solid potassium oxalate, shake frequently during 15-20 minutes and filter through
a dry, plaited paper returning the first runnings to the filter until the filtrate runs
clear. Pipette 150 cc. of the last filtrate into a 600 cc. Erlenmeyer flask, add 5 cc. of
concentrated hydrochloric acid and boil under a reflux condenser for 2 hours. Cool,
neutralize with solid sodium carbonate, using a little phenolphthalein as indicator,
transfer to a 200 cc. volumetric flask and complete to volume with water. Filter
through a double filter, and return the first runnings until the filtrate becomes
perfectly clear. Determine the dextrose in the filtrate immediately.

VI] LEATHERS 61

9 DETERMINATION.

Determine dextrose in 50 cc. of the solution, as prepared under 8, equivalent to
0.5 gram of leather, according to VIII, 25 and express the result as glucose.

I 0 TOTAL SOLIDS.

Determine as directed under V, 2.

II SOLUBLE SOLIDS.

Determine as directed under V, 4.
1 2 NONTANNINS.

Determine as directed under V, 7.

1 3 SOLUBLE TANNIN.

The difference between the percentage of the soluble solids and the corrected
nontannins is the percentage of tannin.

1 4 NITROGEN.

Determine as directed under I, 21 .

1 5 HIDE SUBSTANCE.

Multiply the percentage of nitrogen by 5.62. The result will be the percentage
of hide substance present.

1 6 COMBINED TANNIN.

Deduct the sum of the percentages of moisture, under 2, insoluble ash, under 4,
soluble solids, under 1 1 , and hide substance, under 1 5, from 100. The result will
be the percentage of combined tannin.

BIBLIOGRAPHY.
1 J. Am. Leather Chem. Assn., 1915, 10: 122.

VII. INSECTICIDES AND FUNGICIDES.
GENERAL METHOD.

1 PREPARATION OF SAMPLE.— TENTATIVE.

Mix thoroughly all samples before analysis. Make water-soluble arsenic deter-
minations on samples as received without further pulverization or drying. In
the case of lye, sodium cyanid or potassium cyanid, weigh large quantities in weigh-
ing bottles and analyze aliquots of the aqueous solutions.

PARIS GREEN.

2 MOISTURE.— TENTATIVE.

Dry 2 grams at 105°-110°C. for 5 hours and express the loss in weight as moisture.

TOTAL ARSENIC.'— OFFICIAL.
(Arsenic, present as arsenate, is titrated as arsenious oxid.)

3 REAGENTS.

(a) Starch indicator . — Mix about 0.5 gram of finely powdered potato starch with
cold water to a thin paste; pour into about 100 cc. of boiling water.

(D) Standard arsenious oxid solution. — Dissolve 2 grams of pure arsenious oxid
in a beaker by boiling with about 150-200 cc. of water containing 10 cc. of concen-
trated sulphuric acid, cool, transfer to a 500 cc. graduated flask and dilute to the
mark.

(C) Standard iodin solution. — Prepare an approximately N/20 solution as fol-
lows: Mix intimately 6.35 grams of pure iodin with twice its weight of pure potas-
sium iodid. Dissolve in a small amount of water, filter and dilute the filtrate to

1 liter in a liter graduated flask. Standardize against b) as follows: Pipette 50
cc. of the arsenious oxid into an Erlenmeyer flask, dilute to about 400 cc, neutralize
with sodium bicarbonate, add 4-5 grams in excess, and add the standard iodin solu-
tion from a burette, shaking the flask continuously, until the yellow color disap-
pears slowly from the solution, then add 5 cc. of the starch indicator and continue
adding the iodin solution, drop by drop, until a permanent blue color is obtained.
Calculate the value of the standard iodin solution in terms of arsenious oxid AsjOj)
and arsenic oxid (AS2O5). Occasionally restandardize the iodin against freshly
prepared arsenious oxid solution.

4 APPARATUS.

The apparatus used is shown in Fig. 5. The distillation flask rests on a metal
gauze which fits over a circular hole in a heavy sheet of asbestos board. The first

2 Erlenmeyer flasks are of 500 and 1000 cc. capacity and contain about 40 and 100
cc. of water, respectively. Both of these flasks should be placed in a pan and kept
surrounded with cracked ice and water. The third flask, containing a small amount
of water, is used as a trap.

63

64

METHODS OF ANALYSIS

[Chap.

0 DETERMINATION.

Weigh an amount of the sample equal to the arsenious oxid equivalent of 250
cc. of the standard iodin solution, and wash into the distillation flask by means of
100 cc. of concentrated hydrochloric acid (sp. gr. 1.19). Add 5 grams of cuprous
chlorid (Cu2Cl2) and distil.

When the volume in the distillation flask is reduced to about 40 cc, add 50 cc.
of concentrated hydrochloric acid by means of the dropping funnel and continue
the distillation until 200 cc. of the acid distillate have passed over. Then wash
down the condenser and all the connecting tubes carefully, transfer these washings
and the contents of the 3 Erlenmeyer flasks to a liter graduated flask and dilute
to the mark. Mix thoroughly, pipette 400 cc. into an Erlenmeyer flask and nearly
neutralize with a saturated solution of sodium or potassium hydroxid, using a few
drops of phenolphthalein as an indicator, keeping the solution well cooled.

Continue as directed under 3 (C) beginning with "neutralize with sodium bicar-
bonate." The number of cc. of iodin used in this titration represents directly
the total per cent of arsenic in the sample expressed as arsenious oxid (As20»).

FIG. 5. APPARATUS FOR DISTILLATION OF ARSENIC CHLORID.

TOTAL ARSENIOUS OXID.

(The following methods determine arsenic, and antimony if present, as the -ous
oxids, AS2O3 and Sb203, respectively. Ferrous and cuprous salts vitiate the results.)

Method I.
C. C. Hedges Method,2 Modified.3— Tentative.

6 REAGENTS.

The reagents and solutions used are described under 3.

7 DETERMINATION.

Weigh an amount of the sample equal to the arsenious oxid equivalent of 100 cc.
of the standard iodin solution, wash into an Erlenmeyer flask with 10-15 cc. of dilute
hydrochloric acid (1 to 1), followed by about 100 cc. of writer, and heat on the steam-
bath to complete solution, at a temperature not exceeding 60°C. Cool, neutralize

VII] INSECTICIDES AND FUNGICIDES 65

with sodium bicarbonate, add 4-5 grams in excess, and then sufficient 25% ammonium
chlorid solution to dissolve the precipitated copper. Dilute somewhat and titrate
as directed under 3 (C). A correction must be applied for the amount of iodin solu-
tion necessary to produce a blue color with starch in the presence of copper I using
an equivalent weight of copper sulphate) . The corrected number of cc. of the stand-
ard iodin solution used represents directly the per cent of arsenious oxid (As20j)
in the sample.

Method II.

8 CM. Smith Method,3 Modified. — Tentative.

Proceed as directed in 7, using dilute sulphuric acid (1 to 4) instead of dilute
hydrochloric. The solution in this case may be heated to boiling.

SODIUM ACETATE-SOLUBLE ARSENIOUS OXID.<— TENTATIVE.

9 REAGENTS.

(a) Sodium oxetate solution. — Prepare a solution containing 12.5 grams of the
crystallized salt (CH3COONa3H20) in each 25 cc.
The other reagents are described under 3.

1 0 DETERMINATION.

Place 1 gram of the sample in a 100 cc. flask and boil for 5 minutes with 25 cc. of
the sodium acetate. Dilute to the mark, shake, and pass through a dry filter
paper. Titrate an aliquot of this filtrate as directed under 3 (C). Calculate the
amount of arsenious oxid (AS2O3) present and express the result as per cent of
sodium acetate-soluble arsenious oxid.

WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE.

11 REAGENTS.

Described under 3.

12 DETERMINATION.

To 1 gram of the sample in a liter Florence flask add 1 liter of recently boiled water
which has been cooled to exactly 32°C. Stopper the flask and place in a water
bath kept at 32°C. by means of a thermostat. Digest for 24 hours, shaking hourly
for 8 hours during this period. Filter through a dry filter and titrate 250 cc. of the
filtrate as directed under 3 (C) . Correct for the amount of the standard iodin neces-
sary to produce the same color, using the same reagents and volume. Calculate
the amount of arsenious oxid (AS2O3) present and express the result as per cent of
water-soluble arsenious oxid.

TOTAL COPPER OXID.

13 Electrolytic Method. — Official.

Treat 2 grams of the sample in a beaker with 100 cc. of water and about 2 grams
of sodium hydroxid and boil thoroughly until all the copper is precipitated as cu-
prous oxid. Filter, wash well with hot water, dissolve the precipitate in hot dilute
nitric acid, cool, transfer to a 250 cc. graduated flask and dilute to the mark. (1)
Use 50-100 cc. of this solution for the electrolytic determination of copper as directed
under VIII, 33 and calculate to per rent cupric oxid; or, (2) Electrolyze the aliquot in
a weighed 150 cc. platinum dish, using a rotating spiral annde and a current of about

66 METHODS OF ANALYSIS [Chap.

3 amperes. After all the copper is deposited (requiring about 30 minutes), wash
the deposit with water by siphoning, then rinse with alcohol, dry for a few min-
utes in an oven, weigh and calculate to per cent cupric oxid.

14 Thiosulphate Method.5 — Official.

Determine copper in another aliquot of the nitric acid solution of copper oxid,
under 13, by titrating with N/20 thiosulphate solution, as directed under VIII, 29,
and calculate to per cent cupric oxid.

LONDON PURPLE.
1 5 MOISTURE.— TENTATIVE.

Determined as directed under 2.

TOTAL ARSENIOUS OXID.8— OFFICIAL.
16 REAGENTS.

Described under 3.

1 7 DETERMINATION.

Dissolve 2 grams of the sample in a mixture of about 80 cc. of water and 20 cc.
of concentrated hydrochloric acid at a temperature of 60°-70°C.; filter and wash
until the combined filtrate and washings measure 250 cc. Treat 100 cc. of this solu-
tion with sodium bicarbonate in excess, transfer to a 500 cc. volumetric flask and
make up to the mark, adding a few drops of ether to destroy the bubbles. Mix
thoroughly and pass through a dry filter. Titrate 250 cc. of the filtrate as directed
under 3 (C) and calculate the per cent of arsenious oxid.

TOTAL ARSENIC OXID.'— OFFICIAL.

18 REAGENTS.

The reagents and solutions used are described under 3.

19 DETERMINATION.

Boil, on a hot plate or over a low flame, 2 grams of the sample with 5 cc. of con-
centrated nitric acid and 20 cc. of concentrated sulphuric acid in a Kjeldahl diges-
tion flask or a covered casserole. After 10-15 minutes add fuming nitric acid or
powdered sodium nitrate, in small quantities at a time, until all organic matter
is destroyed and the solution is practically colorless. Cool, add about 50 cc. of
water \to decompose any nitro-sulphuric acid formed) and heat again until all
nitric acid fumes are expelled. Cool, transfer to a 250 cc. volumetric flask, make
up to the mark with water, mix thoroughly, and filter through a dry filter.

Transfer 50 cc. of this filtrate to a 400 cc. Erlenmeyer flask, dilute with water
to 100 cc, add 1 gram of potassium iodid,8 heat to boiling and evaporate to about
40 cc. (not less). Cool, dilute to 150-200 cc, and remove the excess of iodin with
N/20 sodium thiosulphate. In case the solution is slightly colored from organic
matter or from any cause other than free iodin, add the thiosulphate unt il it is nearly
colorless, then a few drops of the starch indicator, and continue adding t lie thio-
sulphate slowly until the blue color just disappears. Continue at once a-; directed
under 3 C) beginning with "neutralize with sodium bicarbonate." Subtract from
this reading the number of cc. of the standard iodin solution corresponding to the
arsenious oxid obtained in 17. Calculate the per cent of arsenic oxid in the sample.

VII] INSECTICIDES AND FUNGICIDES 67

20 WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE.

Proceed as directed under 12, slightly acidifying the aliquot employed with
hydrochloric acid before adding the excess of sodium bicarbonate.

WATER-SOLUBLE ARSENIC OXID.— TENTATIVE.

21 REAGENTS.

The solutions and reagents used are described under 3.

22 DETERMINATION.

Transfer an aliquot, 250 cc, of the water extract, from 20, to a casserole, add 5
cc. of concentrated sulphuric acid, evaporate to a small volume and heat on a hot
plate till white fumes of sulphuric acid appear. Cover the casserole and add 1-2
cc. of fuming nitric acid and again heat till the appearance of white fumes. Cool,
add a little water and, in order to expel the last traces of nitric acid, once more
evaporate till white fumes appear. Cool, dilute to about 100 cc. with water, add
1 gram of potassium iodids and sufficient sulphuric acid to make the total amount
present about 5 cc. Boil until the volume is reduced to about 40 cc. Cool, dilute
to about 200 cc, remove the excess iodin with N/20 sodium thiosulphate and pro-
ceed as directed under 3 (C) beginning with "neutralize with sodium bicarbonate."
Correct for the amount of the standard iodin solution necessar3" to produce the
same color, using the same reagents and volume. Subtract from the corrected titra-
tion reading the number of cc. of the standard iodin solution corresponding to the
arsenious oxid, obtained in 20. Calculate the per cent of arsenic oxid present.

LEAD ARSENATE.

23 MOISTURE.— TENTATIVE.

a) Powder. — Dry 2 grams to constant weight at 105°-110° C. and report the
loss in weight as moisture.

(b) Paste. — Proceed as under (a), using 50 grams.

Grind the dry sample to a fine powder, mix well, transfer a small portion to a
sample bottle and again dry for 1-2 hours at 105°-110°C., and use this anhydrous
material for the determination of total lead oxid and total arsenic.

TOTAL LEAD OXID.

24 Method I.*— Official.

Heat, on a hot plate, 0.6906 gram of the dry powdered sample with about 25 cc.
of dilute nitric acid (1 to 4) in a 600 cc. beaker. If necessary, remove any insoluble
residue by filtration. Dilute to at least 400 cc, heat nearly to boiling, add am-
monium hydroxid to incipient precipitation, then dilute nitric acid (1 to 10) to re-
dissolve the precipitate, adding 1-2 cc. in excess. Pipette into this solution, kept
almost boiling, 50 cc. of a hot 10% potassium chromate solution, stirring constantly.
Decant while hot through a weighed Gooch, previously heated at 140°-150°C, wash
several times by decantation and then on the filter with boiling water until the
washings are colorless. Dry the lead chromate at 140°-150°C. to constant weight.
The weight of lead chromate multiplied by 100 gives the per cent of lead monoxid
(PbO) in the dried sample.

The lead chromate precipitate may contain a small amount of lead arsenate which
causes slightly high results. This error rarely amounts to more than 0.1-0.L"

68 METHODS OF ANALYSIS [Chap.

Method II. J0— Tentative.
(Not applicable in the presence of calcium.)

25 REAGENT.

Acidified alcohol. — Mix water 100 parts; 95% alcohol 200 parts; and concentrated
sulphuric acid 3 parts by volume.

26 DETERMINATION.

Heat, on a hot plate, 0.7360 gram of the dry powdered sample with about 25 cc.
of dilute nitric acid (1 to 4) in a porcelain evaporating dish or casserole. Remove
any insoluble residue by filtration. Add 3 cc. of concentrated sulphuric acid and
evaporate on the hot plate to the appearance of white fumes. It is important that
all nitric acid be expelled. Cool, add 50 cc. of water and about 100 cc. of 95% alco-
hol, let stand several hours (preferably over-night) and filter through a weighed
Gooch crucible, previously washed with water, the acidified alcohol and 95% alco-
hol, and dried at 200°C. Wash the precipitate of lead sulphate in the crucible about
10 times with the acidified alcohol and then with 95% alcohol until free from sul-
phuric acid. Dry at 200°C. to constant weight, keeping the crucible covered to pre-
vent loss by spattering. The weight of the lead sulphate multiplied by 100 gives
the per cent of lead monoxid (PbO) in the dried sample.

TOTAL ARSENIC.

27 Method I.1— Official.

Proceed as directed under 5, using an amount of the sample equal to the arsenic
oxid equivalent of 500 cc . of the standard iodin solution and titrating a 200 cc . aliquot
of the distillate. The number of cc. used of the standard iodin solution represents
directly the total per cent of arsenic in the sample expressed as arsenic oxid (AsjOs) .

Method II. u— Official.
(Not applicable in the presence of antimony.)

28 REAGENTS.

The reagents and solutions used are described under 3.

29 DETERMINATION.

Dissolve an amount of the powdered sample equal to the arsenic oxid equivalent
of 400 cc. of the standard iodin solution, in dilute nitric acid in a porcelain casserole
or evaporating dish. Add 5 cc. of concentrated sulphuric acid and heat on the
hot plate to copious evolution of white fumes. Wash into a 200 cc. graduated flask
with water, cool, make up to the mark and filter through a dry filter. Transfer
100 cc. of the filtrate to an Erlenmeyer flask and proceed as directed under 22,
beginning with -'add 1 gram of potassium iodid," to "Subtract from the corrected
titration reading." The number of cc. of the standard iodin solution used, divided
by 2, represents directly the per cent of total arsenic in the sample expressed as
arsenic oxid (As20-6).

WATER-SOLUBLE ARSENIC OXID.— TENTATIVE.

30 REAGENTS.

The reagents and solutions used are described under 3.

VII] INSECTICIDES AND FUNGICIDES 69

31

DETERMINATION .

Treat 2 grams of the original sample, if in the form of a powder, or 4 grams, if
a paste, as directed under 12 through "Filter through a dry filter."

Place 250-500 cc. of the clear filtrate in an Erlenmeyer flask, add 3 cc. of con-
centrated sulphuric acid and evaporate on a hot plate. When the volume is re-
duced to about 100 cc, proceed as directed under 22 to "Subtract from the cor-
rected titration reading." Calculate and report as per cent of water-soluble arsenic
oxid%(As206).

CALCIUM ARSENATE.

32 TOTAL ARSENIC— OFFICIAL.

Proceed as directed under 5, using an amount of the powdered sample equal
to the arsenic oxid equivalent of 250 cc. of the standard iodin solution.

The number of cc. of the standard iodin solution used represents directly the
total per cent of arsenic in the sample expressed as arsenic oxid (As206) .

ZINC ARSENITE.

33 TOTAL ARSENIC.i— OFFICIAL.

Proceed as directed under 5, using an amount of the powdered sample equal to
the arsenious oxid equivalent of 500 cc. of the standard iodin solution and titrating
a 200 cc. aliquot of the distillate. The number of cc. of the standard iodin solution
used represents directly the per cent of total arsenic in the sample expressed as ar-
senious oxid (AS2O3).

34 TOTAL ARSENIOUS OXID.— TENTATIVE.
Proceed as directed under 7 or 8.

COPPER CARBONATE.

35 COPPER OXID.— OFFICIAL.

Dissolve a weighed quantity of the substance in dilute nitric acid and deter-
mine copper as directed under 13 or 14.

BORDEAUX MIXTURE.

36 MOISTURE.— OFFICIAL.

(a) Powder. — Dry 2 grams to constant weight at 105°-110°C. and express the
loss in weight as moisture.

(b) Paste. — Heat about 100 grams in an oven at 90-100°C. until dry enough to
powder readily, and note the loss in weight. Powder this partially dried sample,
and determine the remaining moisture in 2 grams as under ia). Determine car-
bon dioxid, as directed under 38, both in the original paste and in this partially
dried sample. Calculate the total moisture by the following formula:

M = a + (100-a) (b + c) - d in which

M = per cent total moisture in original paste;

a = per cent loss in weight of original paste during first drying;

b = per cent loss in weight of partially dried paste during second drying;

c = per cent carbon dioxid remaining in partially dried paste after first

drying;
d = per cent total carbon dioxid in original paste.

70 METHODS OF ANALYSIS [Chap.

CARBON DIOXID"— OFFICIAL.

37 APPARATUS.

This consists of a 200 cc. Erlenmeyer flask closed with a 2-holed stopper; one of
these holes is fitted with a dropping funnel the stem of which extends almost to the
bottom of the flask; the outlet of a condenser, which is inclined upward at an angle
of 30° from the horizontal, passes downward through the other hole. The upper
end of the condenser is connected with a calcium chlorid tube which in turn is
connected with a double U-tube filled in the middle with pumice fragments,* pre-
viously saturated with copper sulphate solution and subsequently dehydrated,
and with calcium chlorid at either end. Then follow 2 weighed U-tubes for absorb-
ing the carbon dioxid, the first filled with porous soda-lime, and the second, one
third with soda-lime and two thirds with calcium chlorid, the latter reagent being
placed at the exit end of the train. A Geissler bulb, partly filled with sulphuric
acid, is attached to the last U-tube to show the rate of gas flow. An aspirator is
connected with the Geissler bulb to draw air through the apparatus. An absorp-
tion tower filled with soda-lime is connected with the mouth of the dropping funnel
to remove carbon dioxid from the air entering the apparatus.

38 DETERMINATION.

Weigh 2 grams of the powder or 10 grams of the paste into the Erlenmeyer flask,
add about 20 cc. of water, attach the flask to the apparatus omitting the 2 weighed
U-tubes, and draw carbon dioxid-free air through the apparatus until the original
air is displaced. Then attach the weighed U-tubes in the position as described in 37,
close the stop-cock of the dropping funnel, fill half full with dilute hydrochloric
acid 1 to 1), reconnect with the soda-lime tower, and allow the acid to flow into
the Erlenmeyer flask, slowly if there is much carbon dioxid, rapidly if there is
little. When effervescence diminishes, place a low Bunsen flame under the flask and
start a flow of water through the condenser, a slow current of air being allowed to
flow through the apparatus at the same time. Maintain a steady but quiet ebulli-
tion, and a slow air current through the apparatus. Boil for a few minutes after
the water has begun to condense in the condenser, then remove the flame and con-
tinue the aspiration of air at the rate of about 2 bubbles per second until the
apparatus is cool. Disconnect the tared absorption tubes, cool in the balance case
and weigh. The increase in weight is due to carbon dioxid.

COPPER.

39 Electrolytic Method. — Official.

Dissolve 2 grams of the dry powdered sample in 20 cc. of water and 5 cc. of con-
centrated nitric acid, dilute to 100 cc, wash into a weighed 150 cc. platinum dish,
and electrolyze, using a rotating spiral anode and a current of about 3 amperes.
After all the copper is deposited (requiring about 30 minutes), wash the deposit
with water by siphoning, then rinse with alcohol, dry for a few minutes in an oven,
and weigh. Calculate the per cent of copper in the sample.

40 Thiosulphate Method. — Official.

Dissolve 2 grams of the dry powdered sample in about 50 cc. of 10% nitric acid,
add ammonium hydroxid solution in excess and heat; then, without removing the
precipitate which is formed, boil off the excess of ammonia, add 5-10 cc. of acetic
acid, cool, add 10 cc. of 30% potassium iodid solution, and titrate as directed under

VIII, 29.

VII] INSECTICIDES AND FUNGICIDES 71

BORDEAUX MIXTURE WITH PARIS GREEN.

41 MOISTURE.— OFFICIAL.
Proceed as directed under 36.

42 CARBON DIOXID.— OFFICIAL.
Proceed as directed under 38.

COPPER.

43 Method I. — Tentative.

Dissolve 2 grams of the dry powdered sample in a few cc. of strong nitric acid,
add 25 cc. of a 3% solution of hydrogen peroxid and warm for 5-10 minutes. Make
slightly alkaline with ammonium hydroxid and then slightly acid again with dilute
nitric acid. Transfer to a weighed 150 cc. platinum dish, add 15-20 cc. of hydrogen
peroxid, dilute to 100 cc. and electrolyze, using a rotating spiral anode and a cur-
rent not exceeding 2 amperes. After the electrolysis has proceeded for about 20
minutes, add to the electrolyte 0.5 gram of ferric sulphate dissolved in a few cc.
of water together with a drop or two of nitric acid. After all the copper is deposited,
wash the deposit with water by siphoning, then rinse with alcohol, dry for a few
minutes in an oven, weigh and calculate the per cent of copper. (Do not pass the
current for more than 5-10 minutes after all the copper has been deposited without
adding more ferric sulphate solution.)

44 Method II.— Tentative.

Treat 1 gram of the dry powdered sample with 20 cc. of water and 5-6 cc. of con-
centrated nitric acid, heat to boiling, cool, and add a slight excess of concentrated
ammonium hydroxid. Wash the solution and precipitate into a weighed platinum
dish of about 150 cc capacity, and electrolyze, using a rotating anode and a cur-
rent of about 4 amperes and 3-4 volts for about 90 minutes or until all the copper
is deposited). Wash the deposit by siphoning until the deposit is clean, being care-
ful not to use too much wash water. Dissolve the copper in 5 cc. of concentrated
nitric acid, dilute to 100 cc. and electrolyze as before, except that all the copper
will be deposited in 30 minutes. Wash the deposit with water by siphoning, then
rinse with alcohol, dry for a minute or so in an oven, weigh and calculate the per
cent of copper.

45 TOTAL ARSENIC.i— OFFICIAL.

Proceed as directed under 5, using an amount of the dry powdered sample equal
to the arsenious oxid equivalent of 500 cc. of the standard iodin solution. The num-
ber of cc. of the standard iodin solution used, divided by 2, represents directly the
per cent of total arsenic in the sample expressed as arsenious oxid (.As2Oj).

TOTAL ARSENIOUS OXID.

46 Method I. —Tentative.

Proceed as directed under 7, using an amount of the dry, powdered sample equal
to the arsenious oxid equivalent of 200 cc. of the standard iodin solution. Before
titrating, all the copper must be in solution. The corrected number of cc. of the
standard iodin solution used, divided by 2, represents directly the per cent of total
arsenious oxid (AS2O3) in the sample.

72 METHODS OF ANALYSIS [Chap.

47 Method II. — Tentative.
Proceed as directed under 8.

48 WATER-SOLUBLE ARSENIOUS OXID.— TENTATIVE.
Proceed a3 directed under 20, using 2 grams of the sample.

BORDEAUX MIXTURE WITH LEAD ARSENATE.

49 MOISTURE.— OFFICIAL.
Proceed as directed under 36.

50 CARBON DIOXID.— OFFICIAL.
Proceed as directed under 38.

51 COPPER.— TENTATIVE.
Proceed as directed under 44.

52 LEAD OXID.3— TENTATIVE.

Dissolve the lead peroxid (which will contain a little arsenic) from the anodes
used in the copper electrolysis, under 51 , by means of dilute nitric acid and a little
hydrogen peroxid, and add to this solution the washings from both electrolyses
of copper. Add ammonium chlorid to dissolve any lead sulphate which may have
precipitated out and make the solution up to 1 liter. Concentrate a 500 cc. aliquot
of this solution to about 300 cc. fall hydrogen peroxid must be expelled from the
solution), transfer to a 400 cc. beaker and precipitate the lead as lead chromate
as directed under 24.

53 TOTAL ARSENIC.!— OFFICIAL.

Proceed as directed under 5, using an amount of the dry, powdered sample equal
to the arsenic oxid equivalent of 500 cc. of the standard iodin solution. The num-
ber of cc. of the standard iodin solution used, divided by 2, represents directly the
per cent of total arsenic in the sample expressed as arsenic oxid (As20s) .

54 WATER-SOLUBLE ARSENIC OXID.— TENTATIVE.

Proceed as directed under 31 .

SODIUM AND POTASSIUM CYANIDS.

55 CYANOGEN.!*— OFFICIAL.

Weigh about 10 grams of the sample in a weighing bottle, dissolve in water, and
make up to volume in a liter graduated flask. To a 50 cc. aliquot add N/20 silver
nitrate, drop by drop, stirring constantly, until 1 drop produces a permanent tur-
bidity. In calculating the results, 1 equivalent of silver is equal to 2 equivalents
of cyanogen, according to the following equation:

2NaCN + AgN03 = NaCNAgCN + NaNO,

Reserve the titrated solution for the determination of chlorin under 56.

VII] INSECTICIDES AND FUNGICIDES 73

56 CHLORIN.h— OFFICIAL.

After completion of the titration for cyanogen, as directed under 55, add a few
cc. of 10% potassium chromate solution as indicator and titrate with N/20 silver
nitrate until the appearance of the red-brown color of silver chromate.

The first titration with silver nitrate represents the cyanogen present according
to the equation above. The second titration represents the cyanogen and chlorin
according to the following equation : NaCNAgCN + NaCl + 2AgN03 = 2NaNOs +
2AgCN + AgCl. Therefore the second minus the first reading represents the chlorin
present in terms of silver nitrate.

SOAP.
MOISTURE.

57 Modified Method of Benedickt and Lewkowitsch .,6 — Tentative.

Weigh about 5 grams of the sample in a tared, 100 cc. beaker, in which is pre-
viously placed a § inch layer of recently ignited, dry sand, and a small glass rod;
if the soap is hard, cut off the soap in very thin strips. Add 25 cc. of alcohol,
or more if necessary, and dissolve on the water bath, stirring constantly. Evapo-
rate the alcohol, heat in an oven at 110°C. until the soap is nearly dry, and weigh,
then dry again for 30 minutes and weigh. Continue this alternate drying and
weighing until the weight changes only a few milligrams during the course of 30
minutes' drying.

58 POTASSIUM AND SODIUMS— TENTATIVE.

Dissolve about 5 grams of the soap in water; decompose with hydrochloric acid,
filter off the water and wash the fat with cold water. Determine both potassium
and sodium in the filtrate as directed under II, 21 .

SODA LYE.

59 CARBONATE AND HYDROXID."— OFFICIAL.

Weigh about 10 grams of the sample from the weighing bottle, dissolve in car-
bon dioxid-free water and make up to a definite volume. Titrate an aliquot of this
solution with N/2 hydrochloric acid, using methyl orange as an indicator, and note
the total alkalinity thus found. Transfer an equal aliquot to a graduated flask
and add enough barium chlorid solution to precipitate all the carbonate, avoiding
any unnecessary excess. Dilute to the mark with carbon dioxid-free water, stopper,
shake, and set aside. When the liquid becomes clear, pipette off one half and ti-
trate with N/2 hydrochloric acid, using phenolphthalein as an indicator. The
number of cc. of N/2 acid, required for this titration, multiplied by 2 gives the num-
ber of cc. of N/2 acid required to neutralize the sodium hydroxid present in the
original aliquot. The difference between this figure and the number of cc. of N/2
hydrochloric acid required for the total akalinity represents the number of cc. of
N/2 acid required to neutralize the sodium carbonate present in the aliquot. Cal-
culate the percentages of sodium carbonate and hydroxid present in the sample.

TOBACCO AND TOBACCO EXTRACT.

NICOTIN.

Kissling Method. — Official.

60 REAGENTS.

(a) Alcoholic sodium hydroxid solution. — Dissolve 6 grams of sodium hydroxid
in 40 cc. of water and 60 cc. of 90% alcohol.

74 METHODS OF ANALYSIS [Chap.

(b) 04% sodium hydroxid solution.

(C) N/10 sulphuric acid. — One cc. is equivalent to 16.22 mg. of nicotin.

(d) Phenacetolin solution. — Prepare a 0.5% alcoholic solution.

(e) Cochineal solution. — Prepare as directed under I, 16 (k).

61 DETERMINATION.

Weigh 5-6 grams of tobacco extract, or 20 grams of finely powdered tobacco
which has been previously dried at 60°C. if necessary, into a small beaker. Add
10 cc. of the alcoholic sodium hydroxid and follow, in the case of tobacco extract,
with enough pure powdered calcium carbonate to form a moist but not lumpy mass.
Mix thoroughly, transfer to a Soxhlet extractor and exhaust for about 5 hours with
ether. Evaporate the ether at a low temperature, and take up the residue with 50
cc. of the 0.4% sodium hydroxid solution. Transfer this residue by means of water
to a 500 cc. Kjeldahl flask, and distil with steam, passing the distillate through a
condenser cooled by a rapidly flowing current of water. Use a 3-bend outflow tube,
and, to prevent bumping and frothing, add a few pieces of pumice, and a small piece
of paraffin. Distil till all the nicotin has passed over, the distillate usually varying
from 400-500 cc. When completed, only about 15 cc. of the liquid should remain in
the flask. Titrate the distillate with N/10 sulphuric acid, using the phenacetolin
or cochineal solution as indicator.

Silicotungstic Acid Method.1* — Official.

62 REAGENTS.

(a) Silicotungstic acid solution. — Prepare a 12% solution of the silicotungstic
acid having the following formula: 4H2O.Si02.12W03.22H20.

(b) Sodium or potassium hydroxid solution (1 to 2).
(C) Dilute hydrochloric acid (1 to 4).

63

DETERMINATION.

Weigh such an amount of the preparation as will contain preferably between 0.1
and 1.0 gram of nicotin ' if the sample contains very little nicotin, about 0.1%, do
not increase the amount to the point where it interferes with the distillation) ; wash
with water into aoOOcc. round-bottomed distillation flask; add a little paraffin to pre-
vent frothing, a few small pieces of pumice and a slight excess of the sodium or
potassium hydroxid, using phenolphthalein as an indicator. Distil rapidly in a
current of steam through a well-cooled condenser, connected by means of an adapter
with a suitable flask containing 10 cc. of the dilute hydrochloric acid. When distil-
lation is well underway, heat the distillation flask to reduce the volume of the liquid
as far as practicable without bumping or undue separation of insoluble matter. Dis-
til until a few cc. of the distillate show no cloud or opalescence when treated with a
drop of the silicotungstic acid and a drop of the dilute hydrochloric acid. Confirm
.the alkalinity of the residue in the distillation flask with phenolphthalein solution.
Make up the distillate, which may amount to 1000-1500 cc, to a convenient volume the
solution may be concentrated on the steam bath without loss of nicotin), mix well
and pass through a large dry filter if not clear. Test a portion with methyl orange
to assure its acidity. Pipette an aliquot, containing about 0.1 gram of nicotin, into
a beaker if the samples contain very small amounts of nicotin, an aliquot contain-
ing as little as 0.01 gram of nicotin may be used), add to each 100 cc. of liquid 3 cc.
of the dilute hydrochloric acid, or more if the necessity is indicated by the test with
methyl orange, and add 1 cc. of the silicotungstic acid for each 0.01 gram of nico-

VII] INSECTICIDES AND FUNGICIDES 75

tin supposed to be present. Stir thoroughly and let stand overnight. Before filter-
ing, stir the precipitate to see that it settles quickly and is in crystalline form; then
filter on an ashless filter paper, and wash with cold dilute hydrochloric acid (1 to
1000). Transfer the paper and precipitate to a weighed platinum crucible, dry
carefully, and ignite until all carbon is destroyed. Finally heat over a Teclu or
Meker burner for not more than 10 minutes. The weight of the residue multiplied
by 0.114 gives the weight of nicotin present in the aliquot.

FORMALDEHYDE SOLUTIONS.

FORMALDEHYDE.

Hydrogen Peroxid Method.19 — Official.

64 REAGENTS.

(a) N/1 sulphuric acid.

(b) N/1 sodium hydroxid. — One cc. is equivalent to 30.02 mg. of formaldehyde.
(C) Hydrogen -peroxid. — An approximately 3% solution. If the hydrogen per-
oxid solution is acid, "neutralize with (D), using litmus solution as indicator.

(d) Litmus solution. — A solution of purified litmus.

65 DETERMINATION.

Measure 50 cc. of N/1 sodium hydroxid into a 500 cc. Erlenmeyer flask and add
50 cc. of the hydrogen peroxid. Then add 3 grams of the formaldehyde solution un-
der examination, allowing the point of the pipette to reach nearly to the liquid in the
flask. Place a funnel in the neck of the flask and heat on the steam bath for 5 min-
utes, shaking occasionally. Remove from the steam bath, wash the funnel with
water, cool the flask to about room temperature, and titrate with N/1 acid, using
the litmus solution as indicator. It is necessary to cool the flask before titration
with the acid to get a sharp end point with the litmus. Calculate the per cent of
formaldehyde.

Cyanid Method.20 — Official.

66 REAGENTS.

(a) N/10 silver nitrate.

(b) N/10 ammonium sidphocyanate.

(C) Potassium cyanid solution. — Dissolve 3.1 grams of potassium cyanid in 500
cc. of water.

(d) 50% nitric acid.

67

DETERMINATION.

Treat 15 cc. of the N/10 silver nitrate with 6 drops of the 50% nitric acid in a
50 cc. volumetric flask; add 10 cc. of the potassium cyanid solution, dilute to the
mark, shake well, filter through a dry filter and titrate 25 cc. of the filtrate with
N/10 ammonium sulphocyanate as directed under III, 15. Acidify another 15 cc.
portion of the N/10 silver nitrate with 6 drops of the 50% nitric acid and treat with
10 cc. of the potassium cyanid solution to which has been added a measured quan-
tity (the weight of which must be calculated from the specific gravity) of the for-
maldehyde solution containing not over 2.5 grams of a 1% solution or the equiva-
lent. Make up to 50 cc, filter and titrate a 25 cc. aliquot with the N/10 ammonium
sulphocyanate for the excess of silver as before. The difference between the num-
ber of cc. of N/10 ammonium sulphocyanate used in these 2 titrations, multiplied

7G METHODS OF ANALYSIS [Chap.

by 2, gives the number of cc. of N/10 ammonium sulphocyanate corresponding to
the potassium cyanid used by the formaldehyde. Calculate the per cent of for-
maldehyde present (1 cc. of N/10 ammonium sulphocyanate is equivalent to 3 mg. of
formaldehyde (HCHO)).

LIME-SULPHUR SOLUTIONS.21
TOTAL SULPHUR— OFFICIAL.

68 PREPARATION OF SOLUTION.

Weigh 10 grams of the solution and dilute to the mark in a 250 cc. graduated
flask with recently boiled and cooled water.

69 DETERMINATION.

Transfer a 10 cc. aliquot to a 400 cc. beaker, add about 3 grams of sodium peroxid,
cover immediately with a watch glass and warm on the steam bath, with frequent
shaking, until all the sulphur is oxidized to sulphate, adding more sodium peroxid
if necessary. Dilute, acidify with hydrochloric acid, evaporate to dryness, treat
with water acidified with hydrochloric acid, boil, and filter to remove silica, if pres-
ent. Dilute the filtrate to 300 cc, add 50 cc. of concentrated hydrochloric acid,"
heat to boiling, and precipitate with 10% barium chlorid solution slowly and stir-
ring constantly. (The rate is best regulated by attaching a suitable capillary tip
to the burette containing the barium chlorid solution.) Evaporate to dryness on
the steam bath, take up with hot water, filter through a quantitative filter paper,
wash until free from chlorin, ignite and heat to constant weight over a Bunsen
burner. Calculate the sulphur from the weight of barium sulphate. Previous to
use test the reagents for sulphur and, if present, make corrections accordingly.

SULPHID SULPHUR.— OFFICIAL.

70 REAGENT.

Ammoniacal zinc solution. — Dissolve 50 grams of pure zinc chlorid in water, add
ammonium hydroxid in sufficient quantity to redissolve the precipitate first formed,
then add 50 grams of ammonium chlorid23 and dilute to 1 liter.

71 DETERMINATION.

Dilute 10 cc. of the solution, prepared as directed under 68, to about 100 cc. and
add the ammoniacal zinc solution until the sulphid is all precipitated, indicated by
the addition of a drop of the clear solution to a few drops of nickel sulphate solution.
Filter immediately, wash the precipitate thoroughly with cold water and transfer
it and the filter paper to a beaker. Cover with water, disintegrate with a glass rod
and add about 3 grams of sodium peroxid, keeping the beaker well covered with a
watch glass. Warm on the steam bath with frequent shaking until all the sulphur
is oxidized to sulphate, adding more sodium peroxid if necessary. Make slightly
acid with hydrochloric acid, filter to remove shreds of filter paper, wash thoroughly
with hot water, and determine the sulphur in the filtrate exactly as under 69.

72 THIOSULPHATE SULPHUR.-OFFICIAL.

Dilute 50 cc. of the solution, prepared as under 68, to about 100 cc. in a 200 cc.
graduated flask. Add a slight excess of the ammoniacal zinc chlorid and dilute to
the mark. Shake thoroughly and filter through a dry filter. To 100 cc. of the fil-
trate add a few drops of methyl orange and exactly neutralise with X 10 hydrochloric

VH] INSECTICIDES AND FUNGICIDES 77

acid. Titrate this neutral solution with approximately N/20 iodin, 3 (C), using a
few drops of starch solution as indicator. From the number of cc. of iodin solu-
tion used, calculate the thiosulphate sulphur present.

73 SULPHATE SULPHUR.— OFFICIAL.

To the solution from the determination in 72, add 2 or 3 drops of hydrochloric
acid, precipitate in the cold with 10% barium chlorid solution, allow to stand over-
night, filter, calculate the sulphur from the weight of barium sulphate and report
as sulphate sulphur.

74 TOTAL LIME.— OFFICIAL.

To 25 cc. of the solution, prepared as under 68, add 10 cc. of concentrated hydro-
chloric acid, evaporate to dryness on the steam bath, treat with water and a little
hydrochloric acid, warm until all the calcium chlorid is dissolved, and filter from sul-
phur and any silica that may be present. Oxidize the filtrate by boiling with a
little concentrated nitric acid, make ammoniacal, filter from iron and aluminium
if present, heat to boiling and precipitate the calcium with ammonium oxalate so-
lution. Filter, wash and ignite over a blast lamp to constant weight; weigh the
residue as calcium oxid.

BIBLIOGRAPHY.

i J. Ind. Eng. Chem., 1916, 8: 327.

2 Ibid., 1909, 1: 208.

» J. Assoc. Official Agr. Chemists, 1915, 1: 436, 446.

* J. Am. Chem. Soc, 1901, 23: 115.

* Ibid., 1902, 24: 1082.

6 Ibid., 1900, 22: 802.

7 U. S. Bur. Chem. Bull. 122, p. 106.

8 Am. J. Sci., 1890, 3rd ser., 40: 66.

9 U. S. Bur. Chem. Bull. 137, p. 40.

10 Ibid., 105, p. 166.

11 Ibid., p. 167.

12 Fresenius. Quantitative Chemical Analysis. Revised and amplified transla-
tion of the 6th German ed., 2: 1180; U. S. Geol. Surv. Bull. 422, p. 179.

13 Sutton. Volumetric Analysis. 10th ed., 1911, p. 207.

14 Ibid., 9th ed., rev., p. 201.

15 Lewkowitsch. Chemical Technology and Analysis of Oils, Fats and Waxes. 5th
ed., 1915, 3: 348.

16 Ibid., 346.

17 Sutton. Volumetric Analysis. 10th ed., 1911, p. 61.

18 U. S. Bur. Animal Industry, Bull. 133.

19 Ber., 1898, 31: 2979; J. Am. Chem. Soc, 1905, 27: 1183; U. S. Bur. Chem. Bull.
99, p. 30; 132, p. 49; 137, p. 47.

20 Z. anal. Chem., 1897, 36: 18; U. S. Bur. Chem. Bull. 132, p. 49.

21 J. Assoc. Official Agr. Cheir.ists, 1915, 1: 76.

22 J. Am. Chem. Soc, 1911, 33: 844.

23 J. Soc Chem. Ind., 1912, 31: 369.

VIII. FOODS AND FEEDING STUFFS.

1 PREPARATION OF SAMPLE.— OFFICIAL.

Grind the sample so that it will pass through a sieve having circular openings
-£s inch (1 mm.) in diameter. If the sample can not be ground, reduce it to as fine a
state as possible.

MOISTURE.

2 Direct Drying. — Official.

Dry a quantity of the substance, representing about 2 grams of dry material,
in a current of dry hydrogen or in vacuo at the temperature of boiling water to
constant weight (approximately 5 hours). If the substance be held in a glass vessel,
the latter should not be in contact with the boiling water.

3 Drying in Vacuo without Heat. — Tentative.

Mix the sample thoroughly and weigh by difference 2-5 gram portions from a
stoppered weighing bottle into tared, covered crucibles. Where subsequent fat
determinations are to be made, fat extraction cones may be used. Substances that
dry down to horn-like material should be mixed with fat-free cotton or other suit-
able material (previously tared with the container). Place 200 cc. of fresh concen-
trated sulphuric acid in a strong, tight 6 inch vacuum desiccator. Put triplicate
samples in separate desiccators, and exhaust by means of a vacuum pump. If a
pump is not available, place 10 cc. of ether in a small beaker in the desiccator, and
exhaust with a water filter pump.

Between the pump and the desiccator interpose an empty bottle, next to the
desiccator, and a bottle of water. Draw the air from the desiccator through the
water and turn the desiccator stop-cock at just the instant when the water begins
to rise in the tube leading from the empty bottle.

Gently rotate the desiccator 4 or 5 times during the first 12 hours to mix the sul-
phuric acid with the water which has collected as an upper layer. At the end of 24
hours open the desiccator, forcing the incoming air to bubble through concentrated
sulphuric acid, and make the first weighing. After weighing place in a desiccator
containing fresh concentrated sulphuric acid and exhaust as before. Rotate the
desiccator several times during the interval and weigh again after a suitable period
of drying. Repeat this process of drying in vacuo over sulphuric acid until the
weight is constant.

4 ASH.— OFFICIAL.

Char a quantity of the substance, representing about 2 grams of the dry material,
and burn until free from carbon at a low heat, not to exceed dull redness. If a
carbon-free ash can not be obtained in this manner, exhaust the charred mass with
hot water, collect the insoluble residue on a filter, burn till the ash is white or nearly
so, and then add the filtrate to the ash and evaporate to dryness. Heat to low
redness till the ash is white or grayish white and weigh.

79

80 METHODS OF ANALYSIS [Chap.

5 CRUDE PROTEIN.— OFFICIAL.

Determine nitrogen as directed under I, 18, 21 , or 23, and multiply the result by
6.25.

ALBUMINOID NITROGEN.— OFFICIAL.

6 REAGENT.

Stutzer's reagent. — Prepare cupric hydroxid as follows: Dissolve 100 grams of pure
copper sulphate in 5 liters of water, add 2.5 cc. of glycerol, and then dilute sodium
hydroxid solution until the liquid is just alkaline; filter, rub the precipitate up with
water containing 5 cc. of glycerol per liter, and wash by decantation or filtration
until the washings are no longer alkaline. Rub the precipitate up again in a mortar
with water containing 10% of glycerol, thus preparing a uniform gelatinous mass
that can be measured with a pipette. Determine the quantity of copper hydroxid
per cc. of this mixture.

7 DETERMINATION.

Place 0.7 gram of the substance in a beaker, add 100 cc. of water, and heat to
boiling ; or, in case of substances rich in starch, heat on the water bath for 10 minutes ;
add a quantity of the Stutzer's reagent containing about 0.5 gram of the hydroxid;
stir thoroughly, filter when cold, wash with cold water, and, without removing the
precipitate from the filter, determine the nitrogen according to I, 18, 21 or 23,
adding sufficient potassium sulphid solution to completely precipitate all of the
copper and mercury. The filter paper used must be practically free from nitrogen.
If the material (such as seeds, seed residue, or oil cake) is rich in alkaline phos-
phates, add, to decompose the alkaline phosphates, 1-2 cc. of a concentrated potash
or soda alum solution, free from ammonia, then the copper hydroxid, and mix well
by stirring. If this is not done, copper phosphate and free alkali may be formed,
and the protein-copper precipitate partially dissolved in the alkaline liquid.

8 AMIDO NITROGEN.— OFFICIAL.

Subtract the amount of albuminoid nitrogen from the amount of total nitrogen
to obtain the amido nitrogen.

CRUDE FAT OR ETHER EXTRACT.

Direct Method. — Official.

9 REAGENT.

Anhydrous ether. — Wash any of the commercial brands of ether with 2 or 3 suc-
cessive portions of water, add solid sodium or potassium hydroxid, and let stand
until most of the water has been abstracted from the ether. Decant into a dry
bottle, add small pieces of carefully cleaned metallic sodium, and let stand until
there is no further evolution of hydrogen gas. Keep the ether, thus dehydrated,
over metallic sodium in lightly stoppered bottles.

1 0 DETERMINATION.

Large quantities of soluble carbohydrates may interfere with the complete ex-
traction of the fat. In such cases extract with water before proceeding with the
determination. Extract about 2 grams of material, dried as under 2 or 3, with the
anhydrous ether for 16 hours. Dry the extract at the temperature of boiling water
for 30 minutes, cool in a desiccator, and weigh; continue, at 30 minutes intervals,
this alternate drying and weighing to constant weight. For most feeds a period
of 1-1 j hours is required.

VIII] FOODS AND FEEDING STUFFS 81

1 1 Indirect Method. — Official.

Determine the moisture, as directed in 2 or 3, then extract the dried substance
for 16 hours as directed under 10, dry again and regard the loss of weight as ether
extract.

Sucrose.

OPTICAL METHODS.

12 GENERAL DIRECTIONS FOR RAW SUGARS.— TENTATIVE.

(Rules1 of the International Commission for Unifying Methods of Sugar Analysis.)

"In general all polarizations are to be made at 20°C."

"The verification of the saccharimeter must also be made at 20°C. For instru-
ments using the Ventzke scale 26 grams of pure dry sucrose, weighed in air with
brass weights, dissolved in 100 metric cc. at 20°C. and polarized in a room, the tem-
perature of which is also 20°C, must give a saccharimeter reading of exactly 100.00.
The temperature of the sugar solution during polarization must be kept constant
at 20°C."

"For countries where the mean temperature is higher than 20°C, saccharimeters
may be adjusted at 30°C. or any other suitable temperature, under the conditions
specified above, provided that the sugar solution be made up to volume and polarized
at this same temperature."

"In effecting the polarization of substances containing sugar employ only half-
shade instruments." The saccharimeter used can be either single or double wedge
and should be a half-shadow instrument with either double or triple field.

" During the observation keep the apparatus in a fixed position and so far removed
from the source of light that the polarizing Nicol is not warmed."

"As sources of light employ lamps which give a strong illumination such as
triple gas burner with metallic cylinder, lens and reflector; gas lamps with Auer
(Welsbach) burner; electric lamp; petroleum duplex lamp; sodium light." When-
ever there is any irregularity in the sources of light such as that due to the convolu-
tions of the filament in the case of electric light or to the meshes of the gauze in the
case of the Welsbach light, place a thin ground-glass plate between the source of
light and the polariscope so as to render the illumination uniform.

"Before and after each set of observations the chemist must satisfy himself of the
correct adjustment of his saccharimeter by means of standardized quartz plates.
He must also previously satisfy himself of the accuracy of his weights, polarization
flasks, observation tubes and cover-glasses. (Scratched cover-glasses must not be
used.) Make several readings and take the mean thereof, but no one reading may
be neglected." Such plates are standardized to read to the second decimal point
and by their use a quick and at the same time accurate test can be made. In using
such plates for testing saccharimeters, it is necessary that the instrument, as well as the
plate, be at 20°C. before making a reading. Different points of the scale, preferably
20°, 50°, 80°, and 100°, (sugar scale) should be tested against the plates.

"In making a polarization use the whole normal weight for 100 cc. or a multiple
thereof for any corresponding volume."

"As clarifying and decolorizing agents use either basic acetate of lead, alumina
cream, or concentrated solution of alum. Boneblack and decolorizing powders are
to be excluded." Whenever reducing sugars are determined ill the solution for po-
larizing, use only neutral lead acetate for clarification as basic load acetate causes
precipitation of some of the reducing sugars. In addition to these clarifying agents,

82 METHODS OF ANALYSIS [Chap.

neutral lead acetate and basic lead nitrate (Herles' solution) have been made official
by the Association.

"After bringing the solution exactly to the mark at the proper temperature, and
after wiping out the neck of the flask with filter paper, pour all of the well-shaken
clarified sugar solution on a rapidly acting filter. Reject the first portions of the
filtrate, and use the rest, which must be perfectly clear, for polarization." It is
advisable to reject the first 20 cc. that run through, then cover the funnel with a
watch glass and use the remainder for polarization. In no case should the whole
solution or any part be returned to the filter. If cloudy after the 20 cc. have been
rejected, begin a new determination.

"Whenever white light is used in polarimetric determinations, the same must be
filtered through a solution of potassium dichromate of such a concentration that the
percentage content of the solution multiplied by the length of the column of the solu-
tion in centimeters is equal to nine." This concentration must be doubled in
reading carbohydrate materials of high rotation dispersion, such as commercial
glucose, etc.

13 PREPARATION AND USE OF CLARIFYING REAGENTS.— TENTATIVE.

(a) Basic lead acetate solution. — Boil 430 grams of neutral lead acetate, 130 grams
of litharge, and 1 liter of water for 30 minutes. Allow the mixture to cool and settle
and dilute the supernatant liquid to a specific gravity of 1.25 with recently boiled
water. Solid basic lead acetate may be substituted for the normal salt and litharge
in the preparation of the solution.

(b) Alumina cream. — Prepare a cold saturated solution of alum in water. Add
ammonium hydroxid with constant stirring until the solution is alkaline to litmus,
allow the precipitate to settle and wash by decantation with water until the wash
water gives only a slight test for sulphates with barium chlorid solution. Pour off
the excess of water and store the residual cream in a stoppered bottle.

(C) Dry basic lead acetate (Home method). — This clarifying agent is obtained as
a dry powdered salt and should contain 72.8% of lead, which corresponds to a com-
position of 3Pb(C2H302)22PbO. Dissolve the normal or half-normal weight of the
sugar solution in a flask with water and complete the volume. Add a small quantity
of the dry salt and shake, then add more and shake again, repeating until completely
precipitated but avoiding any excess. Of this salt 0.1346 gram is equivalent to 1 cc.
of the basic lead acetate solution, described under (a) . When molasses or any other
substance producing a heavy precipitate is being clarified, some dry, coarse sand
should be added to break up the balls of basic lead acetate and the precipitate.
(This method is to have equal weight with the use of a solution of basic lead acetate
in clarifying cane, sorghum, and beet products.)

(d) Neutral lead acetate. — Prepare a saturated solution of neutral lead acetate and
add it to the sugar solution before completing to volume. Its use is imperative when
determining the reducing sugars in the solution used for polarization.

(e) Basic lead nitrate (Herles' solution).— (I) Dissolve 250 grams of lead nitrate
in water and make up to 500 cc. (2) Dissolve 25 grams of sodium hydroxid in water
and make up to 500 cc.

Add equal amounts of (1) and (2) to the sugar solution, shake, and add more if
complete precipitation has not occurred, but avoid any excess. Then complete
the volume with water. When this solution is used for clarification, the factor in the
Clerget determination becomes 143.5 instead of 142.66.

Vni] FOODS AND FEEDING STUFFS 83

DETERMINATION OF SUCROSE IN THE ABSENCE OF RAFFINOSE.

(In the presence of much levulose, as in honeys and fruits products, the optical
method for sucrose gives too high a result.)

14 By Polarization Before and After Inversion with Hydrochloric Acid. — Official.

Dissolve the normal weight (26 grams) of the substance in water, add basic lead
acetate carefully, avoiding any excess, then 1-2 cc. of alumina cream, shake, and
dilute to 100 metric cc, filter, rejecting the first 20 cc. of the filtrate, cover the
filter with a watch glass and, when sufficient filtrate is collected, polarize in a 200
mm. tube. The reading so obtained is the direct reading (P of formula given be-
low) or polarization before inversion. For the invert reading, remove the lead from
the solution either (1) by adding anhydrous potassium oxalate, a little at a time,
to the remaining solution, avoiding an excess and removing the precipitated lead
by filtration; or, (2) by adding anhydrous sodium carbonate under the same con-
ditions. Introduce 50 cc. of the lead-free filtrate into a 100 cc. flask (if sodium
carbonate was used for removing the lead, neutralize carefully the excess of sodium
carbonate with a few drops of dilute hydrochloric acid) and add 25 cc. of water.
Then add, little by little, while rotating the flask, 5 cc. of hydrochloric acid, (sp.gr.
1.20). Heat the flask after mixing, in a water bath kept at 70°C. The temperature
of the solution in the flask should reach 67°-69°C. in 2^-3 minutes. Maintain a
temperature of as nearly 69°C. as possible for 7-7| minutes, making the total time
of heating 10 minutes. Remove the flask and cool the contents rapidly to 20°C.
and dilute to 100 cc. Polarize this solution in a tube provided with a lateral branch
and a water jacket, maintaining a temperature of 20°C. This reading must be
multiplied by 2 to obtain the invert reading. If it is necessary to work at a tem-
perature other than 20°C, which is allowable within narrow limits, the volumes
must be completed and both direct and invert polarizations must be made at exactly
the same temperature.

The inversion may also be accomplished as follows: (1) To 50 cc. of the clarified
solution, freed from lead, add 5 cc. of hydrochloric acid (sp. gr. 1.20) and set aside
for 24 hours at a temperature not below 20°C; or ,(2) If the temperature be above
25°C. set aside for 10 hours. Make up to 100 cc. at 20°C. and polarize as directed
above.

Calculate sucrose by one of the following formulas:

For substances in which the invert solution contains more than 12 grams of invert
sugar per 100 cc. — The following formula is to be used when substances like raw
sugars are polarized:

_ 100 (P - I) . . . .

S = in which

T

142.66

2

S = per cent of sucrose;

P = direct reading normal solution;

I = invert reading normal solution;

T = temperature at which readings are made.
For substances in which the concentration of the invert solution is less than 12 grams
per 100 cc. — The following formula, which takes into account the concentration of the
sugar in solution, should be used in all other cases.

84 METHODS OF ANALYSIS [Chap.

100 (P - I) , . .

S = . — — in which

142.66 - ^ - 0.0065 [ 142.66 - j - (P - I) 1

S = per cent of sucrose;
P = direct reading normal solution;
I = invert reading normal solution;
T = temperature.

By Polarization Before and After Inversion with Invertase. — Tentative.

1 5 REAGENT.

Invertase solution (Hudson Method.2)— Mix 1 kilo of pressed baker's or brewer's
yeast with 1 liter of tap water and 50 cc. of toluene and keep at room temperature
2-3 days to allow autolysis to proceed to the stage of maximum inverting activity.
Then add neutral lead acetate in slight excess, filter, precipitate the lead in the
filtrate with hydrogen sulphid, filter again and then dialyze the filtrate thoroughly
in a collodion sac. Preserve in an ice box the dialyzed solution with the addition
of a little toluene to prevent the growth of micro-organisms. Note the optical
activity of the invertase solution and correct the invert reading according to the
amount of the solution used.

1 6 DETERMINATION.

Dissolve the normal weight (26 grams) of the substance in water, clarify, make
up to volume, and take the direct polarization (P) as directed under 14. If lead
has been used as a clarifying agent, remove the excess of lead from the filtrate, with
anhydrous sodium carbonate or potassium oxalate, and filter. To 50 cc. of the
filtrate in a 100 cc. flask add acetic acid, drop by drop, until the reaction is acid to
litmus, add 10 cc. of the invertase solution, fill the flask with water nearly to 100 cc.
and let stand in a warm place (about 40°C.) overnight. Cool and make up to 100 cc.
at 20°C. Polarize at 20°C. in a 200 mm. tube. Allow the solution to remain in the
tube for an hour and repeat the polarization. If there is no change from the pre-
vious reading, the inversion is complete, whereupon the reading and temperature
of the solution are carefully noted. Correct the reading for the optical activity
of the invertase solution and then multiply by 2. Calculate the percentage of
sucrose by the following formula:

100 (P - I) . , . ,

S = in which

142 - ^ - 0.0065 [l42 - - - (P - 1)1

S = per cent of sucrose;

P = direct reading;

I = invert reading;

T = temperature at which invert reading is made.

1 7 DETERMINATION OF SUCROSE AND RAFFINOSE.— OFFICIAL.

(Of value chiefly in the analysis of beet products.)

If the direct reading is more than 1° higher than the per cent of sucrose as al-
culated by the formula given under 14, raffinose is probably present. Calculate
sucrose and raffinose by the following formula of Herzfeld:

VIII] FOODS AND FEEDING STUFFS 85

„ 0.5124 P - I „ P - S .

S = ; R = in which

0.839 1.852

P = direct reading normal solution;
I = invert reading normal solution;
S = per cent of sucrose;
R = per cent of anhydrous raffinose.

The above formula assumes that the polarizations are made at exactly 20°C.
If the temperature (T) is other than 20°C, the following formula should be used:

P (0.4724 + 0.002 T) - I

o =

Having calculated S, then R =

0.899 - 0.003 T
P- S

1.852

CHEMICAL METHODS.

18 DETERMINATION OF SUCROSE FROM REDUCING SUGARS BEFORE AND AFTER

INVERSION.— TENTATI\ E.

Determine the reducing sugars (clarification having been effected with neutral
lead acetate, never with basic lead acetate), as directed under 25, and calculate to
invert sugar from 27. Invert the solution as directed under 14 or 16, exactly
neutralize the acid, and again determine the reducing sugars, but calculate them
to invert sugar from the same table as referred to above, using the invert sugar
column alone. Deduct the percentage of invert sugar obtained before inversion
from that obtained after inversion, and multiply the difference by 0.95, the result
being the per cent of sucrose. The solutions should be diluted in both determina-
tions so that not more than 245 mg. of invert sugar are present in the amount
taken for reduction. It is important that all lead be removed from the solution
with potassium oxalate before reduction.

Reducing Sugars.

invert sugar.

Approxiniate Volumetric Method for Rapid Work. — Tentative.

19 REAGENT.

Soxhlel's Modification of Fehling's Solution. — Prepare by mixing, immediately
before use. equal volumes of (a) and (b).

(a) Copper sulphate solution. — Dissolve 34.639 grams of copper sulphate (CuSO<
5H20) in water, dilute to 500 cc. and filter through prepared asbestos.

(b) Alkaline tartrate solution. — Dissolve 173 grams of Rochelle salts and 50 grama
of sodium hydroxid in water, dilute to 500 cc, allow to stand for 2 days and filter
through prepared asbestos.

20 STANDARDIZATION OF COPPER SOLUTION.

Since the factor of calculation varies with the minute details of manipulation,
every operator must determine a factor for himself, using a known solution of the
pure sugar that he desires to determine, and keeping the conditions the same as
those used for the determination.

86 METHODS OF ANALYSIS [Chap.

Standardize the solution for invert sugar in the following manner:
Dissolve 4.75 grams of pure sucrose in 75 cc. of water, add 5 cc. of hydrochloric
acid (sp. gr. 1.20) and invert as directed under 14. Neutralize the acid with sodium
hydroxid solution and dilute to 1 liter. Ten cc. of this solution contain 0.050 gram of
invert sugar, which should reduce 10 cc. of the reagent. The strength of the copper
solution should never be taken as a constant, but should be checked against the
sugar.

21 DETERMINATION.

Place 10 cc. of the reagent in a large test tube and add 10 cc. of water. Heat to
boiling, and add gradually small portions of the solution of the material to be tested
until the copper has been completely reduced, boiling after each addition to com-
plete the reaction. Two minutes' boiling is required for complete reduction when
the full amount of sugar solution has been added in one portion. When the end
is nearly reached and the amount of sugar solution to be added can no longer be
judged by the color of the solution, remove a small portion of the liquid and filter
rapidly into a small porcelain crucible or on a test plate; acidify with dilute acetic
acid, and test for copper with dilute potassium ferrocyanid solution. The sugar
solution should be of such strength as will give a burette reading of 15-20 cc, and
the number of successive additions should be as small as possible.

Soxhlet Volumetric Method. — Tentative.

22 REAGENT.

The reagent used is described under 19.

23 DETERMINATION.

Make a preliminary titration to determine the approximate percentage of reduc-
ing sugar in the material under examination. Prepare a solution which contains
approximately 1% of reducing sugar. Place in a beaker 100 cc. of the reagent and
approximately the amount of the sugar solution for its complete reduction. Boil
for 2 minutes. Filter through a folded filter and test a portion of the filtrate for
copper by use of dilute acetic acid and dilute potassium ferrocyanid solution. Re-
peat, varying the volume of sugar solution, until 2 successive amounts are found
which differ by 0.1 cc, one giving complete reduction and the other leaving a small
amount of copper in solution. The mean of these 2 readings is taken as the volume
of the solution required for the complete precipitation of 100 cc. of the reagent.

Under these conditions 100 cc of the reagent require 0.494 gram of invert sugar
for complete reduction. Calculate the percentage by the following formula:

V = the volume of the sugar solution required for the complete reduction of

100 cc. of the reagent;

W = the weight of the sample in 1 cc. of the sugar solution;

100 X 0.494 . . .

— - = per cent of invert sugar.

GRAVIMETRIC METHODS
Munson and Walker General Method.3 — Tentative.

24 REAGENTS.

(a) Asbestos. — Digest the asbestos, which should be the amphibole variety, with
dilute hydrochloric acid (1 to 3) for 2-3 days. Wash free from acid, digest for a

VIII] FOODS AND FEEDING STUFFS 87

similar period with 10% sodium hydroxid solution, and then treat for a few hours
with hot alkaline tartrate solution (old alkaline tartrate solutions that have stood
for some time may be used for this purpose) of the strength employed in sugar de-
terminations. Then wash the asbestos free from alkali, digest for several hours
with dilute nitric acid (1 to 3) and, after washing free from acid, shake with water
into a fine pulp. In preparing the Gooch crucible, make a film of asbestos J inch
thick and wash thoroughly with water to remove fine particles of asbestos. If the
precipitated cuprous oxid is to be weighed as such, wash the crucible with 10 cc. of
alcohol, then with 10 cc. of ether, dry for 30 minutes at 100°C, cool in a desiccator
and weigh.

(b) The solution used is described under 19.

25 PRECIPITATION OF CUPROUS OXID.

Transfer 25 cc. each of the copper sulphate and alkaline tartrate solutions to a
400 cc. beaker of alkali-resisting glass and add 50 cc. of reducing sugar solution, or,
if a smaller volume of sugar solution is used, add water to make the final volume
100 cc. Heat the beaker upon an asbestos gauze over a Bunsen burner, regulate the
flame so that boiling begins in 4 minutes, and continue the boiling for exactly 2
minutes. (It is important that these directions be strictly observed and, in order
to regulate the burner for this purpose, it is advisable to make preliminary tests,
using 50 cc. of the reagent and 50 cc. of water before proceeding with the actual
determination.) Keep the beaker covered with a watch glass during the heating.
Filter the cuprous oxid at once on an asbestos mat in a porcelain Gooch crucible,
using suction. Wash the cuprous oxid thoroughly with water at a temperature of
about 60°C., and either weigh directly as cuprous oxid as in 26, or, determine the
amount of reduced copper by one of the methods under 29-34, respectively. Con-
duct a blank determination, using 50 cc. of the reagent and 50 cc. of water, and, if
the weight of cuprous oxid obtained exceeds 0.5 mg., correct the result of the reducing
sugar determination accordingly. The alkaline tartrate solution deteriorates on
standing and the amount of cuprous oxid obtained in the blank increases.

Determination of Reduced Copper.

26 I. Direct Weighing of Cuprous Oxid. — Tentative.

Prepare a Gooch as directed under 24 (a).

Collect the precipitated cuprous oxid on the mat, as directed under 25, wash
thoroughly with hot water, then with 10 cc. of alcohol, and finally with 10 cc. of
ether. Dry the precipitate for 30 minutes in a water oven at the temperature of
boiling water; cool and weigh. Calculate the weight of metallic copper. Obtain
from 27 the weight of invert sugar equivalent to the weight of copper found.

This method should be used only for determinations in pure sugar solutions. In
all other products the copper of the cuprous oxid should be determined by one of the
following methods, since the cuprous oxid is very apt to be contaminated with
foreign matter.

The number of milligrams of copper reduced by a given amount of reducing sugar
differs when sucrose is present and when it is absent. In the tables the absence of
sucrose is assumed except in the two columns under invert sugar, where one for
mixtures of invert sugar and sucrose containing 0.4 gram of total sugar in 50 cc. of
solution, and one for invert sugar and sucrose when the 50 cc. of solution contains 2
grams of total sugar are given, in addition to the column for invert sugar alone.

88

METHODS OF ANALYSIS

[Chap.

27

Table 1.— Munson and Walker's Table.

For calculating dextrose, invert sugar alone, invert sugar in the presence of sucrose
(0.4 gram and 2 grams total sugar), lactose (wo forms), and maltose {anhydrous and
crystallized) .

[Expressed in milligrams.]

a

INVERT

SUGAR

o

m

LACTOSI

MALTOSl

q

3

o
o

P

AND SUCROSE

5
0

o

A

a

«

"3

~£

0

0

O

q

R

3

vT

6

**

43

H

o

u

a

D
05

a

m

-

w

-

^

O

D
O
05
0.

K

0,

0

K
H

H

B
>

b a

3

U> 3

O
W

6

c

0

O

a
c

D
o

o

D

a

Q

fc

0

w

6

6

6

6

D
0

10

8.9

4.0

4.5

1.6

3.8

4.0

5.9

6.2

10

11

9.8

4.5

5.0

2.1

4.5

4.7

6 7

7.0

11

12

10.7

4.9

5.4

2.5

5.1

5.4

7.5

7.9

12

13

11.5

5.3

6.8

3.0

5.8

6.1

8.3

8.7

13

14

12.4

5.7

6.3

3.4

6.4

6.8

9.1

9.5

14

15

13.3

6.2

6.7

3.9

7.1

7.5

9.9

10.4

15

16

14.2

6.6

7.2

4.3

7.8

8.2

10.6

11.2

16

17

15.1

7.0

7.6

4.8

8.4

8.9

11.4

12.0

17

18

16.0

7.5

8.1

5.2

9.1

9.5

12.2

12.9

18

19

16.9

7.9

8.5

5.7

9.7

10.2

13.0

13.7

19

20

17.8

8.3

8.9

6.1

10.4

10.9

13.8

14.6

20

21

18.7

8.7

9.4

6.6

11.0

11.6

14.6

15.4

21

22

19.5

9.2

9.8

7.0

11.7

12.3

15.4

16.2

22

23

20.4

9.6

10.3

7.5

12.3

13.0

18.2

17.1

23

24

21.3

10.0

10.7

7.9

13.0

13.7

17.0

17.9

24

25

22.2

10.5

11.2

8.4

13.7

14.4

17.8

18.7

25

26

23.1

10.9

11.6

8.8

14.3

15.1

18.6

19.6

26

27

24.0

11.3

12.0

9.3

15.0

15.8

19.4

20.4

27

28

24.9

11.8

12.5

9.7

15.6

16.5

20.2

21.2

28

29

25.8

12.2

12.9

10.2

16.3

17.1

21.0

22.1

29

30

26.6

12.6

13.4

10.7

4.3

16.9

17.8

21.8

22.9

30

31

27.5

13.1

13.8

11.1

4.7

17.6

18.5

22.6

23.7

31

32

28.4

13.5

14.3

11.6

5.2

18.3

19.2

23.3

24.6

32

33

29.3

13.9

14.7

12.0

5.6

18.9

19.9

24.1

25.4

33

34

30.2

14.3

15.2

12.5

6.1

19.6

20.6

24.9

26.2

34

35

31.1

14.8

15.6

12.9

6.5

20.2

21.3

25.7

27.1

35

36

32.0

15.2

16.1

13.4

7.0

20.9

22.0

26.5

27.9

36

37

32.9

15.6

16.5

13.8

7.4

21.5

22.7

27.3

28.7

37

38

33.8

16.1

16.9

14.3

7.9

22.2

23.4

28.1

29.6

38

39

34.6

16.5

17.4

14.7

8.4

22.8

24.1

28.9

30.4

39

40

35.5

16.9

17.8

15.2

8.8

23.5

24.8

29.7

31.3

40

41

36.4

17.4

18.3

15.6

9.3

24.2

25.4

30.5

32.1

41

42

37.3

17.8

18.7

16.1

9.7

24.8

26.1

31.3

32 9

42

43

38.2

18.2

19.2

16.6

10.2

25.5

26.8

32 1

33.8

43

44

39.1

18.7

19.6

17.0

10.7

26.1

27.5

32.9

34.6

44

45

40.0

19.1

20.1

17.5

11.1

26.8

28.2

33.7

35.4

45

46

40.9

19.6

20.5

17.9

11.6

27.4

28.9

34.4

36.3

46

47

41.7

20.0

21.0

18.4

12.0

28.1

29.6

35 2

37.1

47

48

42.6

20.4

21.4

18.8

12.5

28.7

30.3

36.0

37.9

48

49

43.5

20.9

21.9

19.3

12.9

29.4

31.0

36.8

38.8

49

50

44.4

21.3

22.3

19.7

13.4

30.1

31.7

37.6

39.6

50

51

45.3

21.7

22.8

20.2

13.9

30.7

32.4

38.4

40.4

51

52

46.2

22.2

23.2

20.7

14.3

31.4

33 0

39.2

41.3

52

53

47.1

22.6

2:1 . 7

21.1

14.8

32.1

33.7

40.0

42 1

53

54

48.0

23.0

24.1

21.6

15.2

32.7

34.4

40.8

42.9

54

55

48.9

23.5

24.6

22.0

15.7

33.4

35.1

41.6

43.8

55

56

49.7

23.9

25.0

22.5

16.2

34.0

35.8

4-2.4

44 6

56

57

50.6

24.3

25.5

22.9

16 6

34.7

36.5

43.2

45.4

57

58

51.5

24.8

25.9

23.4

17.1

35.4

37.2

44 0

46 3

58

59

52.4

25.2

26.4

23.9

17.5

36.0

37.9

44.8

47.1

59

60

53.3

25.6

26.8

24.3

18.0

36.7

38.6

45 6

48.0

60

61

54.2

26.1

27.3

24.8

18.5

37.3

39.3

46.3

48.8

61

62

55.1

26.5

27.7

25.2

18.9

3S.0

40.0

47.1

49.6

62

63

56. 0

27.0

28.2

25.7

19 4

38.6

40.7

47.9

50.5

63

64

56.8

27.4

28.6

26.2

19.8

39.3

41.4

4S.7

51.3

64

viii] foods and feeding stuffs

27 Table 1.— Munson and Walker's Table-

[Expressed in milligrams.]

89

-Continued.

q

3

09
O

INVERT SUfAR
AND SUCROSE

LACTOSE

MALT SE

q

3

o
a

E

o
m
D

o

K
0.
fc>
o

3

o

K

a
a,
a.
o
a

0

a

•2.

H
to

o

PS
H
X

B

a

n

<

o

00
«

m

>

O

s

*- cj

M M

3

^< m

O

"3
o

bfl 3

5

6

q
6
6

6
|

6

O

w

o

K

6

c

0

o

o:

U

o
a
a,

65

57.7

27.8

29.1

26.6

20.3

40.0

42.1

49.5

52.1

65

66

58.6

28.3

29.5

27.1

20.8

40.6

42.8

50.3

53.0

66

67

59.5

28.7

30.0

27.5

21.2

41.3

43.5

51.1

53.8

67

68

60.4

29.2

30.4

28.0

21.7

41.9

44.2

51.9

54 6

68

69

61.3

29.6

30.9

28.5

22.2

42.6

44.8

52.7

55.5

69

70

62.2

30.0

31.3

28.9

22.6

43 3

45.5

53 5

56.3

70

71

63.1

30.5

31.8

29.4

23.1

43.9

46.2

54.3

57.1

71

72

64.0

30.9

32.3

29.8

23.5

44.6

46.9

55.1

58.0

72

73

64.8

31.4

32 7

30.3

24.0

45.2

47.6

55.9

58.8

73

74

65.7

31.8

33.2

30.8

24.5

45.9

48.3

56.7

59.6

74

75

66.6

32.2

33.6

31.2

24.9

46.6

49.0

57.5

60.5

75

76

67.5

32.7

34.1

31.7

25.4

47.2

49.7

58.2

61.3

76

77

68.4

33.1

34.5

32.1

25.9

47.9

50.4

59.0

62.1

77

78

69.3

33.6

35.0

32.6

26.3

48.5

51.1

59.8

63.0

78

79

70.2

34.0

35.4

33.1

26.8

49.2

51.8

60.6

63.8

79

80

71.1

34.4

35.9

33.5

27.3

49.9

52.5

61.4

64.6

80

81

71.9

34.9

36.3

34.0

27.7

50.5

53.2

62.2

65.5

81

82

72.8

35.3

36.8

34.5

28.2

51.2

53.9

63.0

66.3

82

83

73.7

35 8

37.3

34.9

28.6

51.8

54.6

63.8

67.1

83

84

74.6

36.2

37.7

35.4

29.1

52.5

55.3

64.6

68.0

81

85

75.5

36.7

38.2

35.8

29.6

53.1

56.0

65.4

68.8

85

86

76.4

37.1

38.6

36.3

30.0

53.8

56.6

66.2

69.7

86

87

77.3

37.5

39.1

36.8

30.5

54.5

57.3

67.0

70.5

87

88

78.2

38.0

39.5

37.2

31.0

55.1

58.0

67.8

71.3

88

89

79.1

38.4

40.0

37.7

31.4

55.8

58.7

68.5

72.2

89

90

79.9

38.9

40.4

38.2

31.9

56.4

59.4

69.3

73.0

90

91

80.8

39.3

40.9

38.6

32.4

57.1

60.1

70.1

73.8

91

92

81.7

39.8

41.4

39.1

32.8

57.8

60.8

70 9

74.7

82

93

82.6

40 2

41 8

39.6

33.3

58.4

61.5

71.7

75 5

93

94

83.5

40.6

42.3

40.0

33.8

59.1

62.2

72.5

76.3

94

95

84.4

41.1

42.7

40.5

34.2

59.7

62.9

73.3

77.2

95

96

85.3

41.5

43.2

41.0

34.7

60.4

63.6

74.1

78.0

96

97

86.2

42.0

43.7

41.4

35.2

61.1

64.3

74.9

78.8

97

98

87.1

42.4

44.1

41.9

35.6

61.7

65.0

75.7

79.7

98

99

87.9

42.9

44.6

42.4

36.1

62.4

65.7

76.5

80.5

99

100

88.8

43.3

45.0

42.8

36.6

63.0

66.4

77.3

81.3

100

101

89.7

43.8

45 5

43.3

37.0

63.7

67.1

78.1

S2.2

101

102

90.6

44.2

46.0

43.8

37.5

64.4

67.8

78.8

83.0

102

103

91.5

44.7

46.4

44.2

38.0

65.0

68.5

79.6

83.8

103

104

92.4

45.1

46.9

44.7

38.5

65.7

69.1

80.4

84.7

104

105

93.3

45.5

47.3

45.2

38.9

66.4

69.8

81.2

85.5

105

106

94.2

46.0

47.8

45.6

39.4

67.0

70.5

82.0

86.3

106

107

95.0

46.4

48.3

46.1

39.9

67.7

71.2

82.8

87.2

107

108

95.9

46.9

48.7

46.6-

40.3

68.3

71 <t

83.6

88.0

108

109

96.8

47.3

49.2

47.0

40.8

69.0

72.6

84.4

88.8

109

110

97.7

47.8

49.6

47.5

41.3

69.7

73.3

85.2

89.7

110

111

98.6

48.2

50.1

48.0

41.7

70.3

74.0

86.0

90.5

111

112

99.5

48.7

50.6

48.4

42.2

71.0

74.7

86.8

91.3

112

113

100.4

49.1

51.0

48.9

42 . 7

71.6

7.-. i

87.6

113

114

101.3

49.6

51 .6

49.4

43.2

72.3

76.1

88.4

93.0

114

115

102.2

50.0

51.9

49.8

43.6

73.0

76.8

89.2

93 9

115

116

103.0

50.5

52.4

50.3

44.1

73.6

77 :.

90 0

94 :

116

117

103.9

50.9

52.9

50.8

44.6

74.3

78 2

90.7

117

118

104.8

51.4

53 ::

51 2

45.0

75.0

78 'i

'U 5

96 i

lis

11!)

105.7

51.8

53.8

61.7

45.5

75.6

7" B

92.3

'.17 J

119

90
27

METHODS OF ANALYSIS

Table 1. — Munsox and Walker's Table.— Continued.

[Expressed in milligrams.!

[Chap.

_

—

INVERT

SUGAR

^

o
5

a
o
o
p

AND SUCROSE

LACTOSE

MALTOSE

C
5

o

*eS

"o5

u

a

0
■
D
O

a

CU

D
o

"5"
o

M

a
cu
a.
o
o

o

■e

a
so
o

«

H

M

m
a

a
<
o

0

■
n
>

O

B

- t-

M M

3

O

o

■

£ u
a 8,

M D
■

c
u
6

O
B

W
6

o

4

6

O

6
W
o

e
■y
C
m
O
o
e
S
E
o

120

106.6

52.3

54.3

52.2

46.0

76.3

80.3

93.1

98.0

120

121

107.5

52.7

54.7

52.7

46.5

76.9

81.0

93.9

98.9

121

122

108.4

53.2

55.2

53.1

46.9

77.6

81.7

94.7

99.7

122

123

109.3

53.6

55.7

53.6

47.4

78.3

82.4

95.5

100.5

123

124

110.1

54.1

56.1

54.1

47.9

78.9

83.1

96.3

101.4

124

125

111.0

54.5

56.6

54.5

48.3

79.6

83.8

97.1

102.2

125

126

111.9

55.0

57.0

55.0

48.8

80.3

84.5

97.9

103.0

126

127

112.8

55.4

57.5

55.5

49.3

80.9

85.2

98.7

103.9

127

128

113.7

55.9

58.0

55.9

49.8

81.6

85.9

99.4

104.7

128

129

114.6

56.3

58.4

56.4

50.2

82.2

86.6

100.2

105.5

129

130

115.5

56.8

58.9

56.9

50.7

82.9

87.3

101.0

106.4

130

131

116.4

57.2

59.4

57.4

51.2

83.6

88.0

101.8

107.2

131

132

117.3

57.7

59.8

57.8

51.7

84.2

88.7

102.6

108.0

132

133

118.1

58.1

60.3

58.3

52.1

84.9

89.4

103.4

108.9

133

134

119.0

58.6

60.8

58.8

52.6

85.5

90.1

104.2

109.7

134

135

119.9

59.0

61.2

59.3

53.1

86.2

90.8

105.0

110.5

135

138

120.8

59.5

61.7

59.7

53.6

86.9

91.5

105.8

111.4

136

137

121.7

60.0

62.2

60.2

54.0

87.5

92.1

106 6

112.2

137

138

122.6

60.4

62.6

60.7

54.5

88.2

92.8

107.4

113.0

138

139

123.5

60.9

63.1

61.2

55.0

88.9

93.5

108.2

113 9

139

140

124.4

61.3

63.6

61.6

55.5

89.5

94.2

109.0

114.7

140

141

125.2

61.8

64.0

62.1

55.9

90.2

94.9

109.8

115.5

141

142

126.1

62.2

64.5

62.6

56.4

90.8

95.6

110.5

116.4

142

143

127.0

62.7

65.0

63.1

56.9

91.5

96.3

111.3

117.2

143

144

127.9

63.1

65.4

63.5

57.4

92.2

97.0

112.1

118.0

144

145

128.8

63.6

65.9

64.0

57.8

92.8

97.7

112.9

118.9

145

146

129.7

64.0

66.4

64.5

58.3

93.5

98.4

113.7

119.7

146

147

130.6

64.5

66.9

65.0

58.8

94.2

99.1

114.5

120.5

147

148

131.5

65.0

67.3

65.4

59.3

94.8

99.8

115.3

121.4

148

149

132.4

65.4

67.8

65.9

59.7

95.5

100.5

116.1

122.2

149

150

133.2

65.9

68.3

66.4

60.2

96.1

101.2

116.9

123.0

150

151

134.1

66.3

68.7

66.9

60.7

96.8

101.9

117.7

123.9

151

152

135.0

66.8

69.2

67.3

61.2

97.5

102.6

118.5

124.7

152

153

135.9

67.2

69.7

67.8

61.7

98.1

103.3

119.3

125.5

153

154

136.8

67.7

70.1

68.3

62.1

98.8

104.0

120.0

126.4

154

155

137.7

68.2

70.6

68.8

62.6

99.5

104.7

120.8

127.2

155

156

138.6

68.6

71.1

69.2

63.1

100.1

105.4

121.6

128.0

156

157

139.5

69.1

71.6

69.7

63.6

100.8

106.1

122.4

128.9

157

158

140.3

69.5

72.0

70.2

64.1

101.5

106.8

123.2

129.7

158

159

141.2

70.0

72.5

70.7

64.5

102.1

107.5

124.0

130.5

159

160

142.1

70.4

73.0

71.2

65.0

102.8

108.2

124.8

131.4

160

161

143.0

70.9

73.4

71.6

65.5

103.4

108.9

125.6

132.2

161

162

143.9

71.4

73.9

72.1

66.0

104.1

109 6

126.4

133.0

162

163

144.8

71.8

74.4

72.6

66.5

104.8

110.3

127.2

133.9

163

164

145.7

72.3

74.9

73.1

66.9

105.4

111.0

128.0

134.7

104

165

146.6

72.8

75.3

73.6

67.4

106.1

111.7

128.8

135.5

165

166

147 5

73.2

75.8

74.0

67.9

106.8

112.4

129.6

136.4

166

167

148.3

73.7

76.3

74.5

68.4

107.4

113.1

130.3

137.2

167

168

149.2

74.1

76.8

75.0

68.9

10S.1

113.8

131.1

138.0

168

169

150.1

74.6

77.2

75.5

69.3

108.8

114.5

131.9

138.9

169

170

151.0

75.1

77.7

76.0

69.8

109.4

115.2

132.7

139 7

170

171

151.9

75.5

78.2

76.4

70.3

110.1

115.9

133 5

140.5

171

172

152.8

76.0

78.7

76.9

70.8

110.8

116.6

134.3

141.4

172

173

153.7

76.4

79.1

77.4

71.3

111.4

117.3

135.1

142 3

173

174

154.6

76.9

79.6

77.9

71.7

112.1

118.0

135.9

143 0

174

VIII] FOODS AND FEEDING STUFFS

27 Table 1.— Munson and Walker's Table.— Continued.

[Expressed in milligrams.)

91

175
176
177
178
179

180
181

182
183
184

185
186
187
188
189

190
191
192
193
194

195
196
197
198
199

200
201
202
203
204

205
206
207
208
209

210
211
212
213
214

215
216
217
218
219

220
221
222
223
224

225

226
227
228
229

155.5
156.3
157.2
158.1
159.0

159 9
160.8
161.7
162.6
163.4

164.3
165.2

166 1

167 0
167.9

168.8

169 7

170 5
171.4
172.3

173.2

174.1
175 0
175 9
176.8

177.7

178 5

179 4
ISO 3
181.2

182 1
183.0
183.9
184 8
185.6

186.5
187 4
188.3
189.2

190 1

191 0

191 9

192 8

193 6
194.5

195 4

196 3

197 2

198 1
199.0

199.9

200 7

201 6
202.5
203.4

77.4

77 8
78.3

78 8
79.2

79.7
80.1
80 6
81.1
81.5

82.0

82.5
82.9

83 4
83.9

84.3

84 8

85 3
85 7
86.2

86.7
87.1

87 6

88 1
88.5

89 0
89.5

89 9

90 4
90.9

91.4

91 8
92.3

92 8
93.2

93.7
94.2
94 6
95.1
95.6

96.1
96.5
97.0
97.5
98.0

98.4

98 9
99.4

99 9
100.3

100.8
101 3
101 8
102.2
102.7

80 1
80 6
81.0
81.5
82.0

82 5
82.9
83.4

83 9
84.4

84.9
85.3

85 8

86 3

87.2
87.7
88.2
88 7
89.2

89.6

90 1
90.6

91 1
91.6

92.0

92 5
93.0
93.5
94.0

94.5
94.9
95.4
95.9
96.4

96.9
97.4
97.8
98.3

99.3
99 8
100.3
100.8
101.2

101.7
102 2
102.7
103.2
103.7

104.2
104.6
105.1
105.6
106.1

INVERT SUGAR
AND SUCROSE

u to

3

78 4

78 8

79 3
79 8
80.3

80.8
81 3
81 7
82.2
82.7

83.2
83.7
84 2
84.6
85.1

85.6
86 1
86.6
87.1
87.6

88.0
88.5
89 0
89.5
90.0

90.5
91.0
91 4
91 9
92.4

92.9
93.4
93.9
94.4
94.9

95.4
95.8
96.3
96 8
97.3

97.8
98.3
98.8
99 3

100.3
100 8

101
101
102.

102.
103.
103
104
104

72.2
72.7
73.2
73.7
74.2

74.6

75 1
75.6

76 1
76.6

77.1
77.6
78 0
78.5
79.0

79.5
80.0
80.5
81.0
81.4

81.9
82.4
82.9
83 4
83.9

84.4
84.8
85.3
85.8
86.3

86.8
87.3
87.8
88.3

89.2
89.7
90.2
90.7
91.2

91.7
92.2
92.7
93.2
93.7

94 2
94.7
95.1

95 6
96.1

96 6
97.1
97.6

98 1
98.6

112.8
113.4
114.1
114.8
115.4

116.1
116.7
117.4
118.1
118.7

119.4
120.1
120.7
121 4
122.1

122.7
123.4
124 1
121.7
125.4

126.1
126.7

127 4

128 1
128.7

129.4
130.0
130.7
131.4
132.0

132 7
133.4
134 0
134.7
135.4

136 0

136 7

137 4
138.0
138.7

139.4

140 0
140.7

141 4
142.0

142.7

143 4

144 0
111 7
145.4

146 0
146.7
147.4
US 0
148.7

118.7

119 4

120 1
120.8
121.5

122.2
122.9
123.6
124.3
125.0

125.7
126.4
127.1
127.8
128.5

129.2
129 9
130.6
131 3
132.0

132.7
133.4
134.1
134.8
135.5

136.2
136.9

137 6

138 3
139.0

139.7

140 4

141 1
141.8
142.5

143.2
143.9
144.6
145.3
146.0

146 7

147 4
148.1

148.8
149 5

150.2
150.9
151.6
152.3
153.0

153.7
154.4
ISS 1
155 8
156.5

O
K
6

136.7
137.5
138.3
139 1
139.8

140.6

141 4

142 2
143.0
143.8

144.6
145.4
146 2
147.0
147.8

148.6
149 3
150.1
150.9
151.7

152.5
153.3
154.1
154 9
155.7

156.5
157.3
158.1
158.8
159.6

160.4
181.2

162.0
162.8
163.6

164 4
165.2
166 0
166.8
167.5

168 3
160 1
160 9
170.7
171.5

172.3
173 1
173 9
174.7
175.5

176.2

177.0

177 8

178 a

179.4

143.9
144.7
145.5
146.4
147.2

148.0
148.9
149.7
150.5
151.4

152.2
153.0
153 9
154.7
155.5

156.4
157.2
158.0
158.9
159.7

160.5
161.4
162 2
163.0
163.9

164.7
165.5
166.4
167.2
168.0

168.9
169.7
170 5
171.4
172.2

173.0
173.8
174.7
175.5
176.4

177.2
178.0
178.9
179.7
180.5

181.4

182 2

183 0
183.9
184.7

185.5

IS''. I

187 2

188 a

175
176
177
178
179

180
181
182
183
184

185
186
187
188
189

190
191
192
193
194

195
196
197
198
199

200
201
202
203
204

205
206
207
208
209

210
211
212
213
214

215
216
217
218
219

220
221
222
223
224

225
226
227
228
229

92
27

METHODS OF ANALYSIS

Table 1. — AIunson and Walker's Table.— Continued.

[Expressed in milligrams.]

[Chap.

,_

—

INVERT

SUGAR

_

o
5

o
o
p

AND SUCROSE

LACTOSE

MA'TOSE

5

o

lmmi

__

u

a

C9

Q

a"

o
2.

<

o

O

O

q

a

o

O

w

fcJ

a

_

*tl

HH

0

IS
0

B!

o

§s

6

q

q

6

09

D

o

K
ft

o

w

ft

K

0

o

ia

Q

a
a

>

3
o

U 3
tn

B

6

6

a

n

o

o

i

0.

D

O

230

204.3

103.2

106.6

105.2

99.1

149.4

157.2

180 2

189.7

230

231

205.2

103.7

107.1

105.7

99.6

150 0

157.9

181.0

190.5

231

232

206.1

104.1

107.6

106.2

100.1

150.7

158 6

1«1.8

191 3

232

233

207.0

104.6

108.1

106.7

100.6

151.4

159.3

182.6

192.2

233

234

207.9

105.1

108.6

107.2

101.1

152.0

160.0

183.4

193.0

234

235

208.7

105.6

109.1

107.7

101.6

152.7

160 7

184.2

193 8

235

236

209.6

106.0

109.5

108.2

102.1

153.4

161.4

184.9

194 7

236

237

210.5

106.5

110.0

108.7

102.6

154.0

162.1

185 7

105.5

237

238

211.4

107.0

110.5

109.2

103.1

154.7

162.8

186.5

196.3

238

239

212.3

107.5

111.0

109.6

103.5

155.4

163.5

187.3

197.2

239

240

213.2

108.0

111.5

110.1

104.0

156.1

164.3

188.1

198 0

240

241

214.1

108.4

112.0

110.6

101.5

156.7

165.0

188.9

198.8

241

242

215 0

108.9

112.5

111 1

105.0

157.4

165.7

189 7

199.7

242

243

215.8

109.4

113.0

111.6

105 5

158 1

166.4

190.5

200.5

243

244

216.7

109.9

113.5

112.1

106.0

158.7

167.1

191.3

201.3

244

245

217.6

110 4

114.0

112.6

106.5

159.4

167.8

192 1

202.2

245

246

218.5

110.8

114.5

113.1

107.0

160.1

168.5

192.9

203.0

246

247

219.4

111.3

115.0

113.6

107.5

160.7

169.2

193 6

203.8

247

248

220.3

111.8

115.4

114.1

108.0

101.4

169.9

194.4

204.7

248

249

221.2

112.3

115.9

114.6

108.5

162.1

170.6

195.2

205.5

249

250

222.1

112.8

116.4

115.1

109.0

162.7

171.3

196.0

205 3

250

251

223.0

113.2

116.9

115.6

109.5

163.4

172.0

196.8

207 2

251

252

223.8

113.7

117.4

116.1

110.0

164 1

172.7

197.6

208 0

252

253

224.7

114.2

117.9

116.6

110.5

164 7

173.4

198.4

208.8

253

254

225.6

114.7

118.4

117.1

111.0

165.4

174.1

199.2

209.7

254

255

226.5

115.2

118.9

117.6

111.5

166.1

174.8

200.0

210.5

255

256

227.4

115.7

119.4

118.1

112.0

166.8

175.5

200.8

211.3

256

257

228.3

116.1

119.9

118.6

112.5

167.4

176 2

201.6

212 2

257

258

229.2

116.6

120.4

119.1

113.0

168.1

176 9

202.3

213 0

258

259

230.1

117.1

120.9

119.6

113.5

168.8

177.6

203.1

213.8

259

260

231.0

117.6

121.4

120.1

114.0

169.4

178.3

203.9

214.7

260

261

231.8

118.1

121 9

120.8

114.5

170.1

179 0

204.7

215 5

261

262

232.7

118.6

122.4

121.1

115.0

170.8

179.8

205.5

216.3

262

263

233.6

119.0

122.9

121.6

115.5

171.4

180.5

206.3

217.2

263

264

234.5

119.5

123.4

122.1

116.0

172.1

1S1.2

207.1

218.0

264

265

235.4

120.0

123.9

122.6

116.5

172.8

181.9

207.9

218.8

285

266

236.3

120.5

124.4

123.1

117.0

173.5

182.6

208.7

219.7

266

267

237.2

121.0

124.9

123.6

117.5

174.1

183.3

209.5

220.5

267

268

238.1

121.5

125.4

124.1

118.0

174.8

184.0

210.3

221.3

288

269

238.9

122.0

125.9

124.6

118.5

175.5

184.7

211.0

222.1

269

270

239.8

122.5

126.4

125.1

119 0

176.1

185.4

211.8

223.0

270

271

240.7

122.9

126.9

12.5.6

119.5

176.8

186.1

212.6

223 8

271

272

241.6

123.4

127.4

126.2

120.0

177.5

186.8

213.4

224 6

272

273

242.5

123.9

127.9

126.7

120.6

178.1

187.5

214 2

225 5

273

274

243.4

124.4

128.4

127.2

121.1

178.8

188.2

215.0

226.3

274

275

244.3

124.9

128.9

127.7

121.6

179.5

188.9

215.8

227 1

275

276

245.2

125.4

129.4

128.2

122.1

180.2

189.6

216.6

276

277

246.1

125.9

129.9

128.7

122.6

180 8

190.3

217.4

228 B

277

278

246.9

126.4

130.4

129.2

123.1

181 5

191.0

218 2

229 6

27S

279

247.8

126.9

130.9

129.7

123.6

182 2

191.7

218.9

230.5

279

280

248.7

127.3

131.4

130.2

124.1

182.8

192 4

219.7

231 3

2S0

281

249.6

127.8

131 9

130.7

124 6

183.5

193 1

220 5

232 1

281

282

250 5

128.3

132.4

131 2

125 1

184 2

193.9

221 3

233 0

283

283

251.4

128.8

132 .9

131 7

125 6

184 8

194 6

222 1

284

252.3

129.3

133.4

132.2

126.1

L85 5

195.3

222 9

234 6

284

VIII] FOODS AND FEEDING STUFFS

27 Table 1.— Munson and Walker's Table.— Continued.

[Expressed in milligrams.]

93

6

3

~5
o

N

a
e.
p.
o
o

i

03
O

o

p
J

?

a

o
«

H
K
H

a

P5
■4
O

p
a

E-c

K

m

>
z

INVERT SUGAR
AND 8UCR SE

LACTOSE

MALTOSE

q
S

o

a
H
o
m

P

O

a

0.
P
o

"3
O

9

03 t-

h «*

tL if

3
O

"3
o

DO

S u

03 03
bti 3

C-3

6
6

O

o
w

6

6

6

O

6
W
6

o

a

M

O

00

P

O
es

0.

s

o

285

253.2

129.8

133.9

132.7

126.6

186.2

196.0

223.7

235.5

285

286

254.0

130.3

134.4

133.2

127.1

186.9

196.7

224.5

236.3

286

287

254.9

130.8

134.9

133.7

127.6

187.5

197.4

225.3

237.1

287

288

255.8

131.3

135.4

134.3

128.1

188.2

198.1

226.1

238.0

288

289

256.7

131.8

135.9

134.8

128.6

188.9

198.8

226.9

238.8

289

290

257.6

132.3

136.4

135.3

129.2

189.5

199.5

227.6

239.6

290

291

258.5

132.7

136.9

135.8

129.7

190.2

200.2

228.4

240.5

291

292

259.4

133.2

137.4

136 3

130.2

190.9

200.9

229.2

241.3

292

293

260.3

133.7

137.9

136.8

130.7

191.5

201.6

230.0

242.1

293

294

261.2

134.2

138.4

137.3

131.2

192.2

202.3

230.8

242.9

294

295

262.0

134.7

138.9

137.8

131.7

192.9

203.0

231.6

243.8

295

296

262.9

135.2

139.4

138.3

132.2

193.6

203.7

232.4

244.6

296

297

263.8

135.7

140.0

13S.8

132.7

194.2

204.4

233.2

245.4

297

298

264.7

136.2

140 .5

139.4

133.2

194.9

205.1

234.0

246.3

298

299

265.6

136.7

141.0

139.9

133.7

195.6

205.8

234.8

247.1

299

300

266.5

137 2

141.5

140.4

134.2

196.2

206.6

235.5

247.9

300

301

267.4

137.7

142.0

140.9

134.8

196.9

207.3

236.3

248.8

301

302

268.3

138.2

142.5

141.4

135.3

197.6

208.0

237.1

249.6

302

303

269.1

138.7

143.0

141.9

135.8

198.3

208.7

237.9

250.4

303

304

270.0

139.2

143.5

142.4

136.3

198.9

209.4

238.7

251.3

304

305

270.9

139.7

144.0

142.9

136.8

199.6

210.1

239.5

252.1

305

306

271.8

140.2

144.5

143.4

137.3

200.3

210.8

240.3

252.9

308

307

272.7

140.7

145.0

144.0

137.8

201.0

211.5

241.1

253.8

307

308

273.6

141.2

145.5

144.5

138.3

201.6

212.2

241.9

254.6

308

309

274.5

141.7

146.1

145.0

138.8

202.3

212.9

242.7

255.4

309

310

275.4

142.2

146.6

145.5

139.4

203.0

213.7

243.5

256.3

310

311

276.3

142.7

147 1

146.0

139.9

203.6

214.4

244.2

257.1

311

312

277.1

143.2

147.6

146.5

140.4

204.3

215.1

245.0

257.9

312

313

278.0

143.7

148.1

147.0

140.9

205.0

215.8

245.8

258.8

313

314

278.9

144.2

148.6

147.6

141.4

205.7

216.5

246.6

259.6

314

315

279.8

144.7

149.1

148.1

141.9

206.3

217.2

247.4

260.4

315

316

280.7

145.2

149.6

148.6

142 4

207.0

217.9

248.2

261.2

316

317

281.6

145.7

150.1

149.1

143 0

207.7

218.6

249.0

262.1

317

318

282.5

146.2

150.7

149.6

143. S

2&S.4

219.3

249.8

262.9

318

319

283.4

146.7

151.2

150.1

144.0

209.0

220.0

250.6

263.7

319

320

284.2

147.2

151.7

150.7

144.5

209.7

220.7

251.3

264.6

320

321

285.1

147.7

152.2

151.2

145 0

210.4

221.4

252 1

265.4

321

322

286.0

148.2

152.7

151 7

145.5

211.0

222.2

252.9

266.2

322

323

286.9

148.7

153.2

152.2

146.0

211.7

222.9

253.7

267.1

323

324

287.8

149.2

153.7

152.7

146.6

212.4

223.6

254.5

267.9

324

325

288.7

149.7

154.3

153.2

147.1

213.1

224.3

255.3

268.7

325

326

289.6

150.2

154.8

153 8

147.6

213.7

225.0

256.1

269.6

326

327

290.5

150.7

155.3

154.3

148.1

214 4

225.7

256.9

270.4

327

328

291.4

151.2

155.8

154.8

148.6

215.1

226.4

257 7

271.2

328

329

292.2

151.7

156.3

155.3

149.1

215.8

227.1

258.5

272.1

329

330

293.1

152.2

156.8

155.8

149.7

216.4

227.8

259.3

272.9

330

331

294.0

152.7

157.3

156.4

150 2

217.1

228.5

260.0

273.7

331

332

294.9

153.2

157.9

156.9

150.7

217.8

229.2

260.8

274 r,

332

333

295.8

153.7

158 1

157.4

151.2

21S.4

230.0

261.6

L'7.-» 4

333

334

296.7

154.2

158.9

157.9

151.7

219.1

230.7

262.4

276.2

334

335

297.6

164.7

159.4

158.4

152.3

219.8

231.4

263.2

277.0

335

336

298.5

155.2

159.9

159.0

152 8

220 5

232.1

264 0

277 9

336

337

299.3

155.8

llil :,

159 5

L53.3

221 l

264.8

337

338

300.2

156.3

161.0

160.0

153.8

221.8

233.5

279 ■">

3iS

339

301.1

156.8

161.5

160.5

164.3

222.5

231.2

266.4

280.4

339

94
27

methods of analysis
Table 1. — Munson and Walker's Table.

[Expressed in milligrams.]

[Chap.

-Continued.

o
3

"a
O

K

a
p.
S
o

BO

o
o

p

>J
o

w
n
o
a

H

K
m

a

K
■<
O
P

00

H

«

>

55

INVERT SUGAR
AND SUCROSE

LACTOSE

MALTOSE

5

5

o

Q
0

CO

t>

o

K

o

s

« l.

t£ to

B
o

o

S3

to 3
03

q
6

O

6

1
6

6
K
o

O

q
6

o
a

M

o

■
a
o

H

6.
D

D

340

302.0

157.3

162.0

161.0

154.8

223.2

234.9

267.1

281.2

340

341

302.9

157.8

162.5

161.6

155.4

223.8

235.6

267.9

282.0

341

342

303.8

158.3

163.1

162.1

155.9

224.5

236.3

268.7

282.9

342

343

304.7

158.8

163.6

162.6

156.4

225.2

237.0

269.5

283.7

343

344

305.6

159.3

164.1

163.1

156.9

225.9

237.8

270.3

284.5

344

345

306.5

159.8

164.6

163.7

157.5

226.5

238.5

271.1

285.4

345

346

307.3

160.3

165.1

164.2

158.0

227.2

239.2

271.9

286.2

348

347

308.2

160.8

165.7

164.7

158.5

227.9

239.9

272.7

287.0

347

348

309.1

161.4

166.2

165.2

159.0

228.5

240.6

273.5

287.9

348

349

310.0

161.9

166.7

165.7

159.5

229.2

241.3

274.3

288.7

349

350

310.9

162.4

167.2

166.3

160.1

229.9

242.0

275.0

289.5

350

351

311.8

162.9

167.7

166.8

160.6

230.6

242.7

275.8

290 4

351

352

312.7

163.4

168.3

167.3

161.1

231.2

243.4

276.6

291.2

352

353

313.6

163.9

168.8

167.8

161.6

231.9

244.1

277.4

292.0

353

354

314.4

164.4

169.3

168.4

162.2

232.6

244.8

278.2

292.8

354

355

315.3

164.9

169.8

168.9

162.7

233.3

245.6

279.0

293.7

355

356

316.2

165.4

170.4

169.4

163.2

233.9

246.3

279.8

294.5

356

357

317.1

166.0

170.9

170.0

163.7

234.6

247.0

280.6

295.3

357

358

318.0

166.5

171.4

170.5

164.3

235.3

247.7

281.4

296 2

358

359

318.9

167.0

171.9

171.0

164.8

236.0

248.4

282.2

297.0

359

360

319.8

167.5

172.5

171.5

165.3

236.7

249.1

282.9

297.8

360

361

320.7

168.0

173.0

172.1

165.8

237.3

249.8

283.7

298.7

361

362

321.6

168.5

173.5

172.6

166.4

238.0

250.5

284.5

299.5

362

363

322.4

169.0

174.0

173.1

166.9

238.7

251.2

285.3

300.3

363

364

323.3

169.6

174.6

173.7

167.4

239.4

252.0

286.1

301.2

364

365

324.2

170.1

175.1

174.2

167.9

240.0

252.7

286.9

302.0

365

366

325.1

170.6

175.6

174.7

168.5

240.7

253.4

287.7

302.8

366

367

326.0

171.1

176.1

175.2

169.0

241.4

254.1

288.5

303.6

367

368

326.9

171.6

176.7

175.8

169.5

242.1

254.8

289.3

304.5

368

369

327.8

172.1

177.2

176.3

170.0

242.7

255.5

290.0

305.3

369

370

328.7

172.7

177.7

176.8

170.6

243.4

256.2

290.8

306.1

370

371

329.5

173.2

178.3

177.4

171.1

244.1

256.9

291.6

307 0

371

372

330 4

173.7

178.8

177.9

171.6

244.8

257.7

292.4

307.8

372

373

331.3

174.2

179.3

178.4

172.2

245.4

258.4

293.2

308.6

373

374

332.2

174.7

179.8

179.0

172.7

246.1

259.1

294.0

309.5

374

375

333.1

175.3

180.4

179.5

173.2

246.8

259.8

294.8

310.3

375

376

334.0

175.8

180.9

180.0

173.7

247.5

260.5

295.6

311.1

378

377

334.9

176.3

181.4

180.6

174.3

248 1

261.2

296.4

312.0

377

378

335.8

176.8

182.0

181.1

174.8

248.8

261.9

297.2

312.8

378

379

336.7

177.3

182.5

181.6

175.3

249.5

262.6

297.9

313.6

379

380

337.5

177.9

183.0

182.1

175.9

250.2

263.4

298.7

314.5

380

381

338.4

178.4

183.6

182.7

176.4

250.8

264.1

299.5

315.3

381

382

339.3

178.9

184.1

183.2

176.9

251.5

264.8

300.3

316.1

382

383

340.2

179.4

184.6

183.8

177.5

252.2

265.5

301.1

316.9

383

384

341.1

180.0

185.2

184.3

178.0

252.9

266.2

301.9

317.8

384

385

342.0

180.5

185.7

184.8

178.5

253.6

266.9

302.7

31S.6

385

386

342.9

181.0

186.2

185.4

179.1

254.2

267.6

303.5

319.4

3S8

387

343.8

181.5

186.8

185.9

179.6

254.9

268.3

304.2

320.3

387

388

344.6

182.0

187.3

186.4

180.1

255.6

269.0

305.0

321.1

388

389

345.5

182.6

187.8

187.0

180.6

256.3

269.8

305.8

321.9

389

390

346.4

183.1

188.4

187.5

181.2

256.9

270.5

306.6

322.8

390

391

347.3

183.6

188.9

188.0

181.7

257.6

271.2

307.4

323.6

391

392

348.2

184.1

189.4

188.6

182.3

258.3

271.9

308 2

324.4

392

393

349.1

184.7

190.0

189. 1

182.8

259.0

272 6

309.0

325.2

393

394

350.0

185.2

190.5

189.7

183.3

259.6

273.3

309. S

326.1

394

VIII]

FOODS ANT

FEEDING STUFFS

95

27

Table 1.—

MUNSON AND WALKER'S TABLE-

-Continued.

[Expressed in m

Iligrams.]

„

a

INVERT SUGAR

jf_^

o

3

CO

o
o

D

AND SUCROSE

LACTOSE

MALTOSE

q
3

o

„

^

O

0

•J

o

13

<

3

o

eg

o

O

O

a

6

~3

a

o
U

w

n

H

o

go

M

a

00

D

H

o

H

es u

s Is

O

q

q

o

p

o

«
P.
D
O

w

B<

0.

o
o

«

X

a

0

W

z

3
O

U 3

a

c5

6

d

6

o
«

Pa

O
o

395

350.9

185.7

191.0

190.2

183.9

260.3

274.0

310.6

326.9

395

396

351.8

186.2

191.6

190.7

184.4

261.0

274.7

311.4

327.7

396

397

352.6

186.8

192 1

191.3

184.9

261.7

275.5

312.1

328.6

397

398

353.5

187.3

192.7

191.8

185.5

262.3

276.2

312.9

329.4

398

399

354.4

187.8

193.2

192.3

186.0

263.0

276.9

313.7

330.2

399

400

355.3

188.4

193.7

192.9

186.5

263.7

277.6

314.5

331.1

400

401

356.2

188.9

194.3

193.4

187.1

264.4

278.3

315.3

331.9

401

402

357.1

189.4

194.8

194.0

187.6

265.0

279.0

316.1

332.7

402

403

358.0

189.9

195.4

194.5

188.1

265.7

279.7

316.9

333.6

403

404

358.9

190.5

195.9

195.0

188.7

266.4

280.4

317.7

334.4

404

405

359.7

191.0

196.4

195.6

189.2

267.1

281.1

318.5

335 2

405

406

360.6

191.5

197.0

196.1

189.8

267 8

281.9

319.2

336.0

406

407

361.5

192.1

197.5

196.7

190.3

268.4

282.6

320.0

336 9

407

408

362.4

192.6

198.1

197.2

190.8

269.1

283.3

320.8

337.7

408

409

363.3

193.1

198.6

197.7

191.4

269.8

284.0

321.6

338.5

409

410

364.2

193.7

199.1

198.3

191.9

270.5

284.7

322.4

339.4

410

411

365.1

194.2

199.7

198.8

192.5

271.2

285.4

323.2

340.2

411

412

366.0

194.7

200.2

199.4

193.0

271.8

286.2

324.0

341.0

412

413

366.9

195.2

200.8

199.9

193.5

272.5

286.9

324.8

341.9

413

414

367.7

195.8

201.3

200.5

194.1

273.2

287.6

325.6

342.7

414

415

368.6

196.3

201.8

201.0

194.6

273.9

288.3

326.3

343.5

415

416

369.5

196.8

202.4

201.6

195.2

274.6

289.0

327.1

344.4

416

417

370.4

197.4

202.9

202.1

195.7

275.2

289.7

327.9

345.2

417

418

371.3

197.9

203.5

202.6

196.2

275.9

290.4

328.7

346.0

418

419

372.2

198.4

204.0

203.2

196.8

276.6

291.2

329.5

346.8

419

420

373.1

199.0

204.6

203.7

197.3

277 3

291.9

330.3

347.7

420

421

374.0

199.5

205 1

204.3

197.9

277.9

292.6

331.1

348.5

421

422

374.8

200.1

205.7

204.8

198.4

278.6

293.3

331.9

349.3

422

423

375.7

20'). 6

206.2

205.4

19S.9

279.3

294.0

332.7

350.2

423

424

376.6

201.1

206.7

205.9

199.5

280.0

294.7

333.4

351.0

424

425

377.5

201.7

207.3

206.5

200.0

280.7

295.4

334.2

351.8

425

426

378.4

202.2

207.8

207.0

200.6

281.3

296.2

335.0

352.7

420

427

379.3

202.8

208.4

207.6

201.1

282.0

296.9

335.8

353.5

427

428

380.2

203.3

208.9

208.1

201.7

282.7

297.6

336.6

354.3

428

429

381.1

203.8

209.5

208.7

202.2

283 4

298.3

337.4

355.1

429

430

382.0

204.4

210.0

209.2

202.7

284.1

299.0

338.2

356.0

430

431

382.8

204.9

210.6

209.8

203.3

284.7

299.7

339.0

356.8

431

432

383.7

205.5

211.1

210.3

203.8

285.4

300.5

339.7

357.6

432

433

384.6

206.0

211.7

210.9

204.4

286.1

301.2

340.5

358.5

433

434

385.5

206.5

212.2

211.4

204.9

286.8

301.9

341.3

359.3

434

435

386.4

207.1

212.8

212.0

205.5

287.5

302.6

342.1

360.1

435

436

387.3

207.6

213.3

212.5

206.0

288.1

303.3

342 9

361.0

436

437

388.2

20S.2

213.9

213.1

206.6

288.8

304.0

343.7

361.8

437

438

389.1

208.7

214.4

213.fi

207.1

289.5

304.7

344.5

382 fi

433

439

390.0

209.2

215.0

214.2

207.7

290.2

305.5

345 3

363.4

439

440

390.8

209.8

215.5

214.7

208.2

290.9

306.2

346.1

364.3

440

441

391.7

210.3

216.1

215.3

203.8

291.5

306.9

346.8

365 1

441

442

392.6

210.9

216.6

215.8

209.3

292.2

307.6

347 6

365 9

442

443

393.5

211.4

217.2

216.4

209.9

292.9

308.3

348.4

366.8

443

444

394.4

212.0

217.8

216.9

210.4

293.6

309.0

349.2

367 6

444

445

395.3

212.5

218.3

217.5

211.0

294.2

309.7

350.0

368.4

445

446

396.2

213.1

218.9

218 0

211 5

294 9

310.5

350.8

369.3

446

447

397.1

213.6

219.4

218.6

212.1

295.6

311 2

351.6

370 1

417

448

397.9

214 1

220.0

219 1

212.6

296.3

311 9

352 4

370 0

448

449

398.8

214.7

220.5

219.7

213.2

297.0

312.6

353 2

371 ;

449

96
27

METHODS OF ANALYSIS

Table 1. — Munson and Walker's Table.— Continued.

[Expressed in milligrams.]

[Chap.

q

CO

INVERT SUGAR
AND SUCROSE

LACTOSE

MALTOSE

q

5

8

"3

"3

o

a

^

o

PS

<

"o

o

O

q

a

V,

o

00

D

c

in

3

o

M

a
p.
p.

B

00

o

0
00

H

s

DB

O

q

q

6

o
a

M

f

PS

a
>

u c3

tij 3

w

W

|

O

a
p.

D
D

O

a
a

g

o

ea

6

6

6

o

D

D

450

399.7

215.2

221.1

220.2

213.7

297.6

313.3

353 9

372.6

450

451

400.6

215.8

221.6

220.8

214.3

298.3

314.0

354.7

373 4

451

452

401.5

216 3

222.2

221.4

214.8

299.0

314.7

355.5

374.2

452

453

402.4

216.9

222.8

221.9

215.4

299.7

315.5

356.3

375.1

453

454

403.3

217.4

223.3

222.5

215.9

300.4

316.2

357.1

375.9

454

455

404.2

218.0

223.9

223.0

216.5

301.1

316.9

357.9

376.7

455

456

405.1

218.5

224 4

223.6

217.0

301.7

317 6

358.7

377.6

456

457

405.9

219.1

225.0

224.1

217.6

302.4

318.3

359.5

378.4

457

458

406.8

219.6

225.5

224.7

218.1

303.1

319.0

360.3

379.2

458

459

407.7

220.2

226.1

225.3

218.7

303.8

319.8

361.0

380.0

459

460

408.6

220.7

226.7

225.8

219.2

304 5

320.5

361.8

380.9

460

461

409.5

221.3

227.2

226.4

219.8

305.1

321.2

362.6

381.7

461

462

410.4

221.8

227.8

226.9

220.3

305.8

321.9

363.4

382.5

462

463

411.3

222.4

228.3

227.5

220.9

306.5

322.6

364.2

383.4

463

464

412.2

222.9

228.9

228.1

221.4

307.2

323.4

365.0

384.2

464

465

413.0

223.5

229.5

228.6

222.0

307.9

324.1

365.8

385.0

465

466

413.9

224.0

230.0

229.2

222.5

308.6

324 .8

366.6

385.9

466

467

414.8

224.6

230.6

229.7

223.1

309.2

325.5

367.3

386.7

467

468

415.7

225.1

231.2

230.3

223.7

309.9

326.2

368.1

387.5

468

469

416.6

225.7

231.7

230.9

224.2

310.6

326.9

368.9

388.3

469

470

417.5

226.2

232.3

231.4

224.8

311.3

327.7

369.7

389.2

470

471

418.4

226.8

232.8

232.0

225.3

312.0

328.4

370.5

390 0

471

472

419.3

227.4

233.4

232.5

225.9

312.6

329.1

371.3

390.8

472

473

420.2

227.9

234.0

233.1

226.4

313.3

329.8

372.1

391.7

473

474

421.0

228.5

234.5

233.7

227.0

314.0

330.5

372.9

392.5

474

475

421.9

229.0

235.1

234.2

227.6

314.7

331 3

373.7

393.3

475

476

422.8

229.6

235.7

234.8

228.1

315 4

332.0

374 4

394.2

476

477

423.7

230.1

236.2

235.4

228.7

316.1

332.7

375.2

395.0

477

478

424.6

230.7

236.8

235.9

229.2

316.7

333.4

376.0

395.8

478

479

425.5

231.3

237.4

236.5

229.8

317.4

334.1

376.8

396.6

479

480

426.4

231.8

237.9

237.1

230.3

318.1

334.8

377.6

397.5

480

481

427.3

232.4

238.5

237.6

230.9

318.8

335.6

378.4

398.3

481

482

428.1

232.9

239.1

238.2

231.5

319.5

336 3

379.2

399.1

482

483

429.0

233.5

239.6

238.8

232.0

320.1

337.0

380.0

400.0

483

484

429.9

234.1

240.2

239.3

232.6

320.8

337.7

380.7

400.8

484

485

430.8

234.6

240.8

239.9

233.2

321.5

338.4

381.5

401.6

485

486

431.7

235.2

241.4

240.5

233.7

322.2

339.1

382.3

402.4

486

487

432.6

235.7

241.9

241.0

234 . 3

322.9

339.9

383.1

403.3

487

488

433.5

236.3

242.5

241.6

234.8

323.6

340.6

383.9

404.1

4-S

489

434.4

236.9

243.1

242.2

235.4

324.2

341.3

384.7

404.9

480

490

435.3

237.4

243.6

242.7

236.0

324.9

342.0

385.5

405.8

490

28

//. A. H. Low Volumetric Method, Modified/ — Tentative.

Standard thiosulphate solution. — Prepare a solution of sodium thiosulphate
containing 19 grams of pure crystals in 1 liter. Weigh accurately about 0.2
gram of pure copper foil and place in a flask of 250 cc. capacity. Dissolve by warming
with 5 cc. of a mixture of equal volumes of strong nitric acid and water. Dilute
to 50 cc, boil to expel the red fumes, add 5 cc. of strong bromin water, and boil

VIII] FOODS AND FEEDING STUFFS 97

until the bromin is completely driven off. Remove from the heat and add a slight
excess of strong ammonium hydroxid (about 7 cc. is required). Again boil until
the excess of ammonia is expelled, as shown by a change of color of the liquid,
and a partial precipitation. Then add a slight excess of strong acetic acid (3 or 4
cc. of 80% acid) and boil for a minute. Cool to room temperature and add 10 cc.
of 30% p :tassium iodid solution. Titrate at once with the thiosulphate solution
until the brown tinge has become weak, then add sufficient starch indicator [VII,
3 (a)] to produce a marked blue coloration. Continue the titration cautiously
until the color due to free iodin has entirely vani hed. The blue color changes to-
ward the end to a faint lilac. If at this point the thiosulphate be added drop by drop
and a little time allowed for complete reaction after each addition, there is no diffi-
culty in determining the end point within a single drop. One cc. of the thiosulphate
solution will be found to correspond to about 0.005 gram of copper.

29

DETERMINATION.

After washing the precipitated cuprous oxid, cover the Gooch with a watch
glass and dissolve the oxid by means of 5 cc. of warm nitric acid (1 to 1) poured under
the watch glass with a pipette. Catch the filtrate in a 250 cc. flask, wash the
watch glass and Gooch free of copper, using about 50 cc. of water. Boil to expel
red fumes, add 5 cc. of bromin water, boil off the bromin, and proceed exactly as
in 28.

30 ///. Volumetric Permanganate Method. — Tentative.

Filter and wash the cuprous oxid as directed under 25. Transfer the asbestos
film to the beaker, add about 30 cc. of hot water, and beat the precipitate and asbes-
tos thoroughly. Rinse the crucible with 50 cc. of a hot saturated solution of fe ric
sulphate in 20% sulphuric acid, receiving the rinsings in the beaker containing the
precipitate. After the cuprous oxid is dissolved, wash the solution into a large
Erlenmeyer flask and immediately titrate with a standard solution of potassium
permanganate, 1 cc. of which should 1 e equivalent to 0.010 gram of copper. Stand-
ardize this solution by making 6 or more determinations with the same sugar solu-
tion, titrating one half of the precipitates obtained, and determining the copper in
the others by electrolysis. The average weight of copper obtained by electrolysis,
divided by the average number of cc. of permanganate solution required for the
titrations, gives the weight of copper equivalent to 1 cc. of the standard perman-
ganate solution. A solution standardized with iron or oxalic acid will give too low
a result.

31 IV. Electrolytic Deposition from Sulphuric Acid Solution. — Tentative.

Filter the cuprous oxid in a Gooch, wash the beaker and the precipitate thoroughly
with hot water without transferring the precipitate to the filter. Wash the asbestos
film and the adhering cuprous oxid into the beaker by means of hot dilute nitric acid.
After the copper is all in solution, rcfilter through a thin film of asbestos in a Gooch
and wash thoroughly with hot water. Add 1 ) cc. of sulphuric acid (1 to 4), and
evaporate the filtrate on the steam bath until the copper salt has largely crystal-
lized. Heat carefully on a hot plate or over asbestos until the evolution of white
fumes shows that the excess of nitric acid is removed. Add 8 10 drops <>f nitric acid
(sp. gr. 1.42) and rinse into a 100-125 cc. platinum dish. Deposit the copper by

98 METHODS OF ANALYSIS [Chap.

electrolysis. Wash thoroughly with water, then break the current, wash with alco-
hol and ether successively, dry at about 50°C, and weigh. If preferred, the elec-
trolysis can be conducted in a beaker, the copper being deposited upon a weighed
platinum electrode.

32 V. Electrolytic Deposition from Sulphuric and Nitric Acid S>l>ilion. — Tentative.

Filter and wash as directed under 31 . Transfer the asbestos film from the cru-
cible to the beaker by means of a glass rod and rinse the crucible with about 30 cc.
of a boiling mixture of dilute sulphuric and nitric acids, containing 65 cc. of sul-
phuric acid (sp. gr. 1.84) and 50 cc. of nitric acid (sp. gr. 1.42) per liter. Heat and
agitate until solution is complete; filter and electrolyze as under 31 .

33 VI. Electrolytic Deposition from Nitric Acid Srtution. — Tentative.

Filter and wash as directed under 31. Transfer the asbestos film and adhering
oxid to the beaker. Dissolve the oxid still remaining in the crucible by means of
2 cc. of nitric acid (s i. gr. 1.42), adding it with a pipette and receiving the solution
in the beaker containing the asbestos film. Rinse the crucible with a jet of water,
allowing the rinsings to flow into the beaker. Heat the contents of the beaker until
the copper is all in solution, filter, dilute the filtrate to a volume of 100 cc. or more,
and electrolyze. When a nitrate solution is electrolyzed, the first washing of the
deposit should be made with water acidulated with sulphuric acid, in order to remove
all the nitric acid before the current is interrupted.

34 VII. Reduction in Hydrogen. — Tentative.

Deposit an asbestos film on a perforated platinum disc or cone contained in a
hard glass filtering tube, wash free from loose fibers, dry and weigh. Through this
tube, previously moistened, filter the cuprous oxid immediately, using suction.
Transfer the cuprous oxid to the tube through a removable funnel, and wash thor-
oughly with hot water, alcohol and ether successively. After drying, connect the
tube with a supply of dry hydrogen, heat gently until the cuprous oxid is com-
pletely reduced to metallic copper, cool in the current of hydrogen, and weigh.
If preferred, a Gooch crucible may be used for the filtration.

Herzfeld Gravimetric Method. — Tentative.

Method I.

(For materials containing 1.5% or less of invert sugar and 98.5% or more of sucrose.)

35 REAGENTS.

The reagents and solutions used are described under 24.

36 DETERMINATION.

Prepare the solution of the material to be examined so as to contain 20 grams in
100 cc, free from suspended impurities by filtration and from soluble impurities by
neutral lead acetate, removing the excess of lead by means of sodium carbonate.
Place 50 cc. of the reagent and 50 cc. of the sugar solution in a 250 cc. beaker. Heat
this mixture at such a rate that approximately 4 minutes arc required to bring it
to the boiling point, and boil for exactly 2 minutes. Add 100 cc. of cold, recently
boiled, water. Filter immediately through asbestos, and determine the copper
by one of the met1 ods under 26, 29-34, respectively. Obtain the corresponding
oercentage of invert sugar from 37.

vni]

FOODS AND FEEDING STUFFS

99

37

Table 2.— Herzfeld-s Table.5

For the determination of invert sugar in materials containing 1.5%, or less, of invert
sugar and 98.5%, or more, of sucrose.

COPPER

C PPER

COPPER

REDUCED BT

REDUCED BT

REDUCED BT

10 GRAMS

INVERT SUGAR

10 GRAMS

INVERT SUGAR

10 <;rams

INVERT SUGAR

OF MATERIAL

OF MATERIAL

OF MATERIAL

mg.

per cent

mg.

per cent

mg.

per cent

50

0.05

140

0.51

230

1.02

55

0.07

145

0.53

235

1.05

60

0.09

150

0.56

240

1.07

65

0.11

155

0.59

245

1.10

70

0.14

160

0.62

250

1.13

75

0.16

165

0.65

255

1.16

80

0.19

170

0.68

260

1.18

85

0.21

175

0.71

265

1.21

90

0.24

180

0.74

270

1.24

95

0.27

185

0.76

275

1.27

100

0.30

190

0.79

280

1.30

105

0.32

195

0.82

285

1.33

110

0.35

200

0.85

290

1.36

115

0.38

205

0.88

295

1.38

120

0.40

210

0.90

300

1.41

125

0.43

215

0.93

305

1.44

130

0.45

220

0.96

310

1.47

135

0.48

225

0.99

315

1.50

Method II.
(For materials containing 1.5% or more of invert sugar and 98.5% or less of sucrose.)

38 REAGENTS.

Same as described under 24.

39

DETERMINATION.

Prepare a solution of the material to be examined in such a manner that it con-
tains 20 grams in 100 cc. after clarification and removal of the excess of lead. Pre-
pare a series of solutions in large test tubes by adding 1, 2, 3, 4, and 5 cc. of this
solution to each tube successively. Add 5 cc. of the reagent to each, heat to boiling,
boil 2 minutes, and filter. Note the volume of sugar solution which gives the fil-
trate lightest in tint, but still distinctly blue. Place 20 times this vo ume of the
sugar solution in a 100 cc. flask, dilute to the mark, and mix well. Use 50 cc. of the
solution for the determination, which is conducted as described under 38. For the
calculation of the result use the following formulas and table of factors of Meissl
and Hiller:

Let Cu = the weight of copper obtained;
P = the polarization of the sample;
W = the weight of the sample in the 50 cc. of the solution used for the

determination;
F = the factor obtained from the table for the conversion of copper to
invert sugar;

Cu

2

100

Then — =Z, approximate weight of invert sugar;

Z X — =Y, approximate per cent of invert supar;
W

100

METHODS OF ANALYSIS

[Chap.

100 P

= R, approximate per cent of sucrose in mixture of sugars;

P+ Y

100 — R = I, approximate per cent of invert sugar;

CuF

= per cent of invert sugar.

W

The factor F for calculating copper to invert sugar is then found from 40.

40 Table 3.

Meissl and Hitler's6 factors for determinations in materials in which, of the total
sugars present, 1.5%, or more, is invert sugar, and 9^.5%, or less, is sucrose.

APPROXIMATE ABSOLUTE WEIGHT

OF INVERT 8UGAB (Z)

BATIO OF SUCROSE

TO INVERT

SUGAR = r: I.

200

175

150

125

100

75

so

milligrams

milligrams

milligrams

milligrams

milligrams

milligrams

milligrams

per cent

per cent

per cent

per cent

per cent

per cent

per cent

0: 100

56.4

55.4

54.5

53.8

53.2

53.0

53.0

10:90

56.3

55.3

54.4

53.8

53.2

52.9

52.9

20:80

56.2

55.2

54.3

53.7

53.2

52.7

52.7

30:70

56.1

55.1

54.2

53.7

53.2

52.6

52.6

40:60

55.9

55.0

54.1

53.6

53.1

52.5

52.4

50:50

55.7

54.9

54.0

53.5

53.1

52.3

52.2

60:40

55.6

54.7

53.8

53.2

52.8

52.1

51.9

70:30

55.5

54.5

53.5

52.9

52.5

51.9

51.6

80:20

55.4

54.3

53.3

52.7

52.2

51.7

51.3

90: 10

54.6

53.6

53.1

52.6

52.1

51.6

51.2

91:9

54.1

53.6

52.6

52.1

51.6

51.2

50.7

92:8

53.6

53.1

52.1

51.6

51.2

50.7

50.3

93:7

53.6

53.1

52.1

51.2

50.7

50.3

49.8

94:6

53.1

52.6

51.6

50.7

50.3

49.8

48.9

95:5

52.6

52.1

51.2

50.3

49.4

48.9

48.5

96:4

52.1

51.2

50.7

49.8

48.9

47.7

46.9

97:3

50.7

50.3

49.8

48.9

47.7

46.2

45.1

98:2

49.9

48.9

48.5

47.3

45.8

43.3

40.0

99: 1

47.7

47.3

46.5

45.1

43.3

41.2

38.1

Example: The polarization of a sugar is 86.4, and 50 cc. of solution containing
3.256 grams of sample gave 0.290 gram of copper.

Cu 0.290
2
Z X 100

2

0.145 X

= 0.145 = Z

W "'3.256

100- R = 100-95.1 = I =
R:I = 95.1:4.9

4.45 = Y
4.9

By consulting the table it will be seen that the vertical column headed 1"0 is
nearest to Z, 145, and the horizontal column headed 95: 5 is nearest to the ratio of
R to I, 95.1 : 4.9. Where these columns meet, we find the factor 51.2 which enters
into the final calculation:

CuF

~w

0.290 X 51.2
3.256

= 4.56 per cent of invert sugar.

In case there is no sucrose present, the following table may be used instead of the
factors given in 40.

VIII]
41

foods and feeding stuffs

Table 4.— Meissl-s Table.7
For the determination of invert sugar alone.
[According to Wein.]

[Expressed in milligrams.]

101

COPPER

INVERT
SUGAR

COPPER

INVERT
SUGAR

COPPER

INVERT
SUGAR

COPPER

INVERT
SUGAR

90

46.9

135

70.8

180

95.2

225

120.4

91

47.4

136

71.3

181

95.7

226

120.9

92

47.9

137

71.9

182

96.2

227

121.5

93

48.4

138

72.4

183

96.8

228

122.1

94

48.9

139

72.9

184

97.3

229

122.6

95

49.5

140

73.5

185

97.8

230

123.2

96

50.0

141

74.0

186

98.4

231

123.8

97

50.5

142

74.5

187

99.0

232

124.3

98

51.1

143

75.1

188

99.5

233

124.9

99

51.6

144

75.6

189

100.1

234

125.5

100

52.1

145

76.1

190

100.6

235

126.0

101

52.7

146

76.7

191

101.2

236

126.6

102

53.2

147

77.2

192

101.7

237

127.2

103

53.7

148

77.8

193

102.3

238

127.8

104

54.3

149

78.3

194

102.9

239

128.3

105

54.8

150

78.9

195

103.4

240

128.9

106

55.3

151

79.4

196

104.0

241

129.5

107

55.9

152

80.0

197

104.6

242

130.0

108

56.4

153

80.5

198

105 . 1

243

130.6

109

56.9

154

81.0

199

105.7

244

131.2

110

57.5

155

81.6

200

106.3

245

131.8

111

58.0

156

82.1

201

106.8

246

132.3

112

58.5

157

82.7

202

107.4

247

132.9

113

59.1

158

83.2

203

107.9

248

133.5

114

59.6

159

83.8

204

108.5

249

134.1

115

60.1

160

84.3

205

109.1

250

134.6

116

60.7

161

84.8

206

109.6

251

135.2

117

61.2

162

85.4

207

110.2

252

135.8

118

61.7

163

85.9

208

110.8

253

136.3

119

62.3

164

86.5

209

111.3

254

136.9

120

62.8

165

87.0

210

111.9

255

137.5

121

63.3

166

87.6

211

112.5

256

138.1

122

63.9

167

88.1

212

113.0

257

138.6

123

64.4

168

88.6

213

113.6

258

139.2

124

64.9

169

89.2

214

114.2

259

139.8

125

65.5

170

89.7

215

114.7

260

140.4

126

66.0

171

90.3

216

115.3

201

140 9

127

66.5

172

90.8

217

115.8

262

141.5

128

67.1

173

91.4

218

116.4

263

142 1

129

67.6

174

91.9

219

117.0

264

142.7

130

68.1

175

92.4

220

117.5

265

143.2

131

68.7

176

93.0

221

lis 1

1 13.8

132

69.2

177

93.5

222

lis. 7

267

1114

133

69.7

178

94.1

223

119.2

268

144.9

134

70.3

179

94.6

224

119.8

269

lir. 5

102
41

42

METHODS OF ANALYSIS

Table 4.— Meissl-s Table.— Continued.

[Expressed in milligrams.]

[Chap.

MALTOSE.

General Gravimetric Method. — Tentative.

INVERT

INVERT

INVERT

INVERT

COPPER

SUGAR

COPPER

SUGAR

COPPER

SUGAR

COPPER

SUGAR

270

146.1

310

169.7

350

193.8

390

218.7

271

146.7

311

170.3

351

194.4

391

219.3

272

147.2

312

170.9

352

195.0

392

219.9

273

147.8

313

171.5

353

195.6

393

220.5

274

148.4

314

172.1

354

196.2

394

221.2

275

149.0

315

172.7

355

196.8

395

221.8

276

149.5

316

173.3

356

197.4

396

222.4

277

150.1

317

173.9

357

198.0

397

223.1

278

150.7

318

174.5

358

198.6

398

223.7

279

151.3

319

175.1

359

199.2

399

224.3

280

151.9

320

175.6

360

199.8

400

224.9

281

152.5

321

176.2

361

200.4

401

225.7

282

153.1

322

176.8

362

201.1

402

226.4

283

153.7

323

177.4

363

201.7

403

227.1

284

154.3

324

178.0

364

202.3

404

227.8

285

154.9

325

178.6

365

203.0

405

228.6

286

155.5

326

179.2

366

203.6

406

229.3

287

156.1

327

179.8

367

204.2

407

230.0

288

156.7

328

180.4

368

204.8

408

230.7

289

157.2

329

181.0

369

205.5

409

231.4

290

157.8

330

181.6

370

206.1

410

232.1

291

158.4

331

182.2

371

206.7

411

232.8

292

159.0

332

182.8

372

207.3

412

233.5

293

159.6

333

183.5

373

208.0

413

234.3

294

160.2

334

184.1

374

208.6

414

235.0

295

160.8

335

184.7

375

209.2

415

235.7

296

161.4

336

185.4

376

209.9

416

236.4

297

162.0

337

186.0

377

210.5

417

237.1

298

162.6

338

186.6

378

211.1

418

237.8

299

163.2

339

187.2

379

211.7

419

238.5

300

163.8

340

187.8

380

212.4

420

239.2

301

164.4

341

188.4

381

213.0

421

239.9

302

165.0

342

189.0

382

213.6

422

240.6

303

165.6

343

189.6

383

214.3

423

241.3

304

166.2

344

190.2

384

214.9

424

242.0

305

166.8

345

190.8

385

215.5

425

242.7

306

167.3

346

191.4

386

216.1

426

243.4

307

167.9

347

192.0

387

216.8

427

244.1

308

168.5

348

192.6

388

217.4

428

244.9

309

169.1

349

193.2

389

218.0

429
430

245.6
246.3

Proceed as directed under 25 and obtain, from 27. the weight of maltose
equivalent to the weight of copper reduced.

VIII]

FOODS AND FEEDING STUFFS

103

Wein Method. — Tentative.

43 REAGENTS.

The reagents and solutions used are described under 24.

44 DETERMINATION.

Place 50 cc. of the reagent in a beaker and heat to the boiling point. When
boiling briskly, add 25 cc. of the maltose solution containing not more than 0.250
gram of maltose and boil for 4 minutes. Filter immediately through asbestos and
determine, by one of the methods given under 26, 29-34 respectively, the amount of
copper reduced.
Obtain, from 45, the weight of maltose equivalent to the weight of copper found.

45

Table 5.

For the determination of maltose.

[According to Wein.8]

[Expressed in milligrams.]

COPPER

CU-
PROUS
OXID

MAL-
TOSE

COPPER

CU-
PROUS
OXID

MAL-
TOSE

COPPER

CU-
PROUS
OXID

MAL-
TOSE

COPPER

CU-
PROUS
OXID

MAL-
TOSE

31

34.9

26.1

71

79.9

61.0

111

125.0

96.4

151

170.0

132.3

32

36.0

27.0

72

81.1

61 .8

112

126.1

97.3

152

171.1

133.2

33

37.2

27.9

73

82 2

62.7

113

127.2

98.1

153

172.3

134.1

34

38.3

28.7

74

83.3

63.6

114

128.3

99.0

154

173.4

135.0

35

39.4

29.6

75

84.4

64.5

115

129.6

99.9

155

174.5

135.9

36

40.5

30.5

76

85.6

65.4

116

130.6

100.8

156

175.6

136.8

37

41.7

31.3

77

86.7

66.2

117

131.7

101 7

157

176.8

137.7

38

42.8

32.2

78

87.8

67.1

118

132.8

102.6

158

177.9

138.6

39

43.9

33.1

79

88.9

68.0

119

134 0

103.5

159

179 0

139.5

40

45.0

33.9

80

90.1

68.9

120

135.1

104.4

160

180.1

140.4

41

46.2

34.8

81

91.2

69 7

121

136.2

105.3

161

181.3

141.3

42

47.3

35.7

82

92.3

70.6

122

137.4

106.2

162

182.4

142.2

43

48.4

36 5

83

93.4

71.5

123

138.5

107.1

163

183.5

143.1

44

49.5

37.4

84

94.6

72.4

124

139.6

108.0

164

184.6

144.0

45

50.7

38.3

85

95.7

73.2

125

140.7

108.9

165

185.8

144.9

46

51.8

39.1

86

96.8

74.1

126

141.9

109.8

166

186.9

145.8

47

52.9

40.0

87

97.9

75.0

127

143 0

110.7

167

188.0

146.7

48

54.0

40.9

88

99.1

75.9

128

144 1

111.6

168

189.1

147.6

49

55.2

41.8

89

100.2

76.8

129

145.2

112.5

169

190 3

148.5

50

56.3

42.6

90

101.3

77.7

130

146.4

113.4

170

191.4

149.4

51

57.4

43.5

91

102 4

78.6

131

147 S

114.3

171

192.5

150.3

52

58.5

44.4

92

103.6

79.5

132

148 6

115 2

172

193.6

151.2

53

59.7

45.2

93

104.7

80.3

133

149.7

116.1

173

194.8

152.0

54

.60.8

46 1

94

105.8

81.2

134

150 9

117.0

174

195 9

152.9

55

61.9

47.0

95

107.0

82.1

135

152.0

117.9

175

197.0

153.8

56

63 0

47.8

96

108.1

83.0

136

153 1

118.8

178

198 1

154.7

57

64.2

48.7

97

109.2

83.9

137

154.2

119.7

177

199.3

155.6

58

65 3

49.6

98

110.3

84.8

138

165.4

120.6

178

200.4

158.5

59

66 4

50.4

99

111.5

85.7

139

156.5

121.5

179

201.5

157.4

60

67.6

51.3

100

112.6

86.6

140

157.6

122.4

180

202.6

158. 3

61

68.7

52.2

101

113.7

87.5

141

158.7

123.3

1S1

203 8

159.2

62

69.8

53.1

102

114.8

88.4

142

159.9

124 2

182

204 9

160.1

63

70.9

53.9

103

116.0

89.2

143

lfil.O

125.1

183

206 0

lfin 9

64

72.1

54 8

104

117 1

90.1

144

162 1

126.0

184

207.1

161.8

65

73.2

65.7

105

118.2

91.0

145

163.2

126.9

185

208.3

162.7

68

74.3

56.6

106

119.3

91.9

146

164.4

127.8

186

209.4

163 6

67

75.4

67.4

107

120 5

92.8

147

165.5

128.7

187

210 5

164 5

68

76.6

58.3

108

121 6

93.7

14S

166.6

129.6

188

211 7

165 4

69

77.7

59.2

109

122.7

94 6

149

167.7

130 5

189

212.8

166 3

70

78.8

60.1

110

123.8

95.5 |

150

168.9

131.4

190

213.9

167.2

104
45

46

METHODS OF ANALYSIS

Table 5. — Continued.
For the determination of maltose.

[Expressed in milligrams.)

[Chap.

CU-

CU-

CU-

cu-

COPPER

PROUS
OXID

MAL-
TOSE

COPPER

PROUS
OXID

MAL-
TOSE

COPPER

PROUS
OXID

MAL-
TOSE

COPPER

1 ROUS
OXID

MAL-
TOSE

191

215.0

168.1

221

248.7

194.8

251

282.6

221.7

281

316.4

248.7

192

216.2

169.0

222

249 9

195.7

252

283 7

222.6

282

317 5

249.6

193

217.3

169.8

223

251.0

196.6

253

284.8

223.5

283

31.8. 6

250 A

194

218.4

170.7

224

252.4

197.5

254

286.0

224.4

284

319.7

251 3

195

219.5

171 6

225

253.3

193.4

255

287.1

225.3

285

320.9

252.3

196

220.7

172.5

226

254.4

199.3

256

288.2

226.2

286

322.0

253.1

197

221.8

173.4

227

255.6

200.2

257

289.3

227 1

287

323.1

254.0

198

222.9

174.3

228

256.7

201.1

258

290.5

228 0

288

324.2

2.54.9

199

224.0

175.2

229

257.8

202 0

259

291 6

228.9

289

325.4

255 8

200

225.2

176.1

230

258.9

202.9

260

292.7

229.8

290

326.5

258.6

201

226.3

177.0

231

260.1

203.8

261

293.8

230.7

291

327 4

257.5

202

227.4

177.9

232

261 2

204.7

262

295.0

231 6

292

328.7

258.4

203

228.5

178.7

233

262.3

205.6

263

296.1

232.5

293

329.9

259.3

204

229.7

179.6

234

263.4

206.5

264

297.2

233.4

294

331.0

260.2

205

230.8

180.5

235

264.6

207.4

265

298.3

234.3

295

332.1

261.1

206

231.9

181.4

236

265.7

208.3

266

299 5

235.2

296

333.2

282.0

207

233.0

182.3

237

266 .8

209 1

267

300.6

236.1

297

334 4

262.8

208

234.2

183.2

238

268.0

210 0

268

301.7

237 0

298

335.5

263.7

209

235.3

184.1

239

269.1

210.9

269

302 8

237.9

299

336.6

264 6

210

236.4

185.0

240

270.2

211.8

270

304.0

238.8

300

337 .8

265.5

211

237.6

185.9

241

271.3

212.7

271

305.1

239.7

212

238.7

186.8

242

272.5

213 6

272

306.2

240.6

213

239.8

187.7

243

273.6

214.5

273

307.3

241.5

214

240.9

188.6

244

274.7

21.5.4

274

308.5

242.4

215

242.1

189.5

245

275.8

216.3

275

309 6

243.3

216

243.2

190.4

246

277.0

217.2

276

310.7

244 2

217

244.3

191.2

247

278.1

218 1

277

311.9

245.1

218

245.4

192.1

248

279.2

219.0

278

313 0

246.0

219

246 6

193.0

249

280.3

219.9

279

314.1

246.9

220

247.7

193.9

250

281.5

220.8

280

315.2

247.8

LACTOSE.
General Gravimetric Method. — Tentative.

Proceed as directed under 25 and obtain, from 27, the weight of lactose
equivalent to the weight of copper reduced.

Soxhlet-Wein Method. — Official.

47 REAGENTS.

The reagents and solutions used are described under 24.

48

DETERMINATION.

Place 50 cc. of the reagent in a beaker and heat to the boiling point. When
boiling briskly, add 100 cc. of the lactose solution containing not more than 0.300
gram of lactose and boil for 6 minutes. Filter immediately through asbestos and
determine by one of the methods given under 26, 29-34 inclusive, the amount of
copper reduced. Obtain, from 49, the weight of lactose equivalent to the weight of
copper found.

VIII]
49

foods and feeding stuffs

Table 6.

For the determination of lactose {Soxhlet-Wein9).
[Expressed in milligrams.)

105

COPPER

LACTOSE

COPPER

LACTOSE

COPPER

LACTOSE

COPPER

LACTOSE

COPPER

LACTOSE

100

71.6

160

116.4

220

161.9

280

208.3

340

255.7

101

72.4

161

117.1

221

162.7

281

209.1

341

256.5

102

73.1

162

117.9

222

103.4

282

209.9

342

257.4

103

73.8

163

118.6

223

164.2

283

210.7

343

258.2

104

74.6

164

119.4

224

164.9

284

211.5

344

259.0

105

75.3

165

120.2

225

165.7

285

212.3

345

259.8

106

76.1

166

120.9

226

166.4

286

213.1

346

260.6

107

76.8

167

121.7

227

167.2

287

213.9

347

261.4

108

77.6

168

122.4

228

167.9

288

214.7

348

262.3

109

78.3

169

123.2

229

168.6

289

215.5

349

263.1

110

79 0

170

123.9

230

169.4

290

216.3

350

263.9

111

79.8

171

124.7

231

170.1

291

217.1

351

264.7

112

80.5

172

125.5

232

170.9

292

217.9

352

265.5

113

81.3

173

126.2

233

171.6

293

218.7

353

266.3

114

82.0

174

127.0

234

172.4

294

219.5

354

267.2

115

82.7

175

127.8

235

173.1

295

220.3

355

268.0

116

83.5

176

128.5

236

173.9

296

221.1

356

268.8

117

84.2

177

129.3

237

174.6

297

221.9

357

269.6

118

85.0

178

130.1

238

175 4

298

222.7

358

270.4

119

85.7

179

130.8

239

176.2

299

223.5

359

271.2

120

86.4

180

131.6

240

176.9

300

224.4

360

272.1

121

87.2

181

132.4

241

177.7

301

225.2

361

272.9

122

87.9

182

133.1

242

178.5

302

225.9

362

273.7

123

88.7

183

133.9

243

179.3

303

226.7

363

274.5

124

89.4

184

134.7

244

180.1

304

227.5

364

275.3

125

90.1

185

135.4

245

180.8

305

228.3

365

276.2

126

90.9

186

136.2

246

181.6

306

229.1

366

277.1

127

91.6

187

137.0

247

182.4

307

229 8

367

277.9

128

92.4

188

137.7

248

183.2

308

230.6

368

278.8

129

93.1

189

138.5

249

184.0

309

231.4

369

279.6

130

93.8

190

139.3

250

184.8

310

232.2

370

280.5

131

94.6

191

140 0

251

185.5

311

232.9

371

281.4

132

95.3

192

140.8

252

186.3

312

233.7

372

282.2

133

96.1

193

141.6

253

1S7.1

313

234.5

373

283.1

134

96.9

194

142.3

254

187.9

314

235.3

374

283.9

135

97.6

195

143.1

255

188.7

315

236.1

375

284.8

136

98.3

196

143.9

256

189.4

316

236.8

376

285.7

137

99.1

197

144.6

257

190.2

317

237.6

377

286.5

138

99.8

198

145.4

258

191.0

318

238.4

378

287.4

139

100.5

199

146.2

259

191.8

319

239.2

379

288.2

140

101.3

200

146.9

260

192.5

320

240.0

380

289.1

141

102.0

201

147.7

261

193.3

321

240.7

381

289.9

142

102.8

202

148.5

262

L94 1

322

241.5

382

290.8

143

103.5

203

149.2

263

194.9

323

242.3

383

291.7

144

104.3

204

150.0

264

195.7

324

' 243.1

3S4

292.5

145

105.1

205

150.7

265

196.4

325

243.9

385

293.4

146

105.8

206

151.5

266

197 2

326

244 6

386

294.2

147

106.6

207

152.2

267

198.0

327

245.4

387

295.1

148

107.3

208

153.0

268

198.8

328

246.2

388

298.0

149

108.1

209

153.7

269

199.5

329

247 0

389

296 B

150

108.8

210

154.5

270

200.3

330

247.7

390

297.7

151

109.6

211

155.2

271

201.1

331

248 5

391

152

110.3

212

156.0

272

201 9

332

249 .2

392

153

111.1

213

156.7

273

202 7

333

250.0

393

300.3

154

111.9

214

157.5

274

203.5

334

250.8

394

301.1

155

112.6

215

158.2

275

204.3

335

251.6

395

802.0

156

113 4

216

159.0

276

205 1

336

S96

157

114.1

217

159 7

277

205.9

337

253.3

397

303 7

158

114.9

218

160.4

278

206.7

338

254 1

398

304 6

159

115.6

219

161.2

279

207.5 ,

339

399
400

305 4
306.3

106 METHODS OF ANALYSIS [Chap.

DEXTROSE.

50 Approximate Volumetric Method for Rapid Work. — Tentative.
Proceed as directed under 21 . Standardize the reagent against pure dextrose.

51 Soxhlet Method. — Tentative.

Proceed as directed under 23. Under these conditions 100 cc. of the reagent
require 0.475 gram of anhydrous dextrose for complete reduction and the formula

becomes : = per cent of dextrose.

vw

52 General Gravimetric Method. — Tentative.

Proceed as directed under 25 and obtain, from 27, the weight of dextrose equiv-
alent to the weight of copper reduced.

Allihn Gravimetric Method. — Tentative.

53 REAGENT.

Allihn's Modification of Fehling's Solution. — Prepare by mixing, immediately
before use, equal volumes of (a) and (b).

(a) Copper sulphate solution. — Dissolve 34.639 grams of copper sulphate
(CuS045H.(0) in water and dilute to 500 cc.

(b) Alkaline tartrate solution. — Dissolve 173 grams of Rochelle salts and 125
grams of potassium hydroxid in water and dilute to 500 cc.

54 DETERMINATION.

Place 30 cc. of the copper sulphate solution, 30 cc. of the alkaline tartrate solu-
tion, and 60 cc. of water in a beaker and heat to boiling. Add 25 cc. of the solution
of the material to be examined, prepared so as not to contain more than 0.25 gram
of dextrose, and boil for exactly 2 minutes, keeping the beaker covered. Filter
immediately through asbestos, and obtain the weight of copper by one of the methods
given under 26, 29-34 inclusive. The corresponding weight of dextrose is found
in 55.

VIII]
55

foods and feeding stuffs

Table 7. — Allihn's Table.10
For the determination of dextrose.

[Expressed in milligrams.]

107

COPPER

CU-
PROUS
OXID

DEX-
TROSE

COPPER

CU-
PROUS
O.WD

DEX-
TROSE

COPPER

CU-
PROUS
OXID

DEX-
TROSE

COPPER

CU-
PROUS
OXID

DEX-
TROSE

11

12.4

6.6

71

79.9

36.3

131

147.5

66.7

191

215.0

97.8

12

13.5

7.1

72

81.1

36.8

132

148.6

67.2

192

216.2

98.4

13

14.6

7.6

73

82.2

37.3

133

149.7

67.7

193

217.3

98.9

14

15.8

8.1

74

83.3

37.8

134

150.9

68.2

194

218.4

99.4

15

16.9

8.6

75

84.4

38.3

135

152.0

68.8

195

219.5

100.0

16

18 0

9.0

76

85.6

38.8

136

153.1

69.3

196

220 7

100.5

17

19.1

9.5

77

86.7

39 3

137

154.2

69.8

197

221 8

101.0

18

20.3

10.0

78

87.8

39.8

138

155.4

70.3

198

222.9

101 5

19

21.4

10.5

79

88.9

40.3

139

156.5

70.8

199

224.0

102.0

20

22.5

11.0

80

90.1

40.8

140

157.6

71.3

200

225.2

102.6

21

23.6

11.5

81

91.2

41.3

141

158.7

71.8

201

226.3

103.1

22

24.8

12.0

82

92.3

41.8

142

159.9

72 3

202

227.4

103.7

23

25.9

12 5

83

93.4

42.3

143

161.0

72.9

203

228.5

104 2

24

27.0

13.0

84

94.6

42.8

144

162.1

73.4

204

229.7

104.7

25

28.1

13.5

85

95.7

43.4

145

163 2

73 9

205

230.8

105.3

26

29.3

14.0

86

96.8

43.9

146

164.4

74.4

206

231.9

105 8

27

30.4

14.5

87

97.9

44.4

147

165.5

74.9

207

233.0

106.3

28

31.5

15.0

88

99.1

44.9

148

166.6

75.5

208

234.2

106.8

29

32.7

15.5

89

100.2

45.4

149

167.7

76.0

209

235.3

107.4

30

33.8

16.0

90

101 3

45.9

150

168.9

76.5

210

236.4

107.9

31

34.9

16.5

91

102.4

46.4

151

170 0

77.0

211

237.6

108.4

32

36.0

17.0

92

103.6

46.9

152

171.1

77.5

212

238.7

109.0

33

37.2

17.5

93

104 7

47.4

153

172.3

78.1

213

239 8

109 5

34

38.3

18.0

94

105.8

47.9

154

173.4

78.6

214

240 9

110 0

35

39.4

18.5

95

107.0

48.4

155

174.5

79.1

215

242.1

110.6

36

40 5

18.9

96

108.1

48.9

156

175.6

79.6

216

243.2

111 1

37

41.7

19.4

97

109.2

49.4

157

176.8

80.1

217

244.3

1116

38

42.8

19.9

98

110.3

49.9

158

177.9

80.7

218

245.4

112.1

39

43.9

20.4

99

111.5

50.4

159

179.0

81.2

219

246.6

112.7

40

45.0

20.9

100

112.6

50.9

160

180.1

81.7

220

247.7

113.2

41

46.2

21.4

101

113.7

51.4

161

181.3

82 2

221

248.7

113.7

42

47.3

21.9

102

114.8

51.9

162

182.4

82.7

222

249.9

114.3

43

48.4

22.4

103

116.0

52.4

163

183.5

83.3

223

251.0

114.8

44

49.5

22.9

104

117.1

52 9

164

184.6

83.8

224

252.4

115 3

45

50.7

23.4

105

118.2

53.5

165

185.8

84.3

225

253.3

115.9

46

51.8

23.9

106

119.3

54.0

166

186.9

84.8

226

254.4

116 4

47

52.9

24.4

107

120.5

54.5

167

188.0

85.3

227

255.6

116.9

48

54 0

24.9

108

121.6

55.0

168

189.1

85.9

228

256.7

117.4

49

55.2

25.4

109

f22.7

55.5

169

190.3

86.4

229

257.8

118 0

50

56.3

25.9

110

123.8

56.0

170

191.4

86.9

230

258.9

118.5

51

57.4

26.4

111

125.0

56.5

171

192.5

87.4

231

260.1

119 0

52

58.5

26.9

112

126.1

57.0

172

193.6

87.9

232

261.2

119 6

53

59.7

27.4

113

127.2

57 5

173

194.8

88.5

233

262.3

120 1

54

60.8

27.9

114

128.3

58.0

174

195.9

89.0

234

263.4

120.7

55

61.9

28.4

115

129.6

58.6

175

197.0

89.5

235

264.6

121.2

56

63.0

28.8

116

130 6

59.1

176

108.1

90.0

230

265.7

121.7

57

64.2

29.3

117

131.7

59.6

177

199.3

90.5

237

266 B

122.3

58

65.3

29.8

118

132.S

60.1

178

200.4

91.1

238

268.0

122.8

59

66.4

30.3

119

134.0

60.6

179

201.5

91.6

239

269.1

123.4

60

67.6

30.8

120

135.1

61.1

180

202 6

92.1

240

270.2

123.9

61

68.7

31.3

121

136.2

61 6

181

203.8

92.6

241

271.3

124 4

62

69.8

31.8

122

137.4

62 1

182

204.9

93 1

212

272 5

125 0

63

70.9

32.3

123

138.5

62.6

183

206.0

93.7

243

27:! 6

125.5

64

72.1

32.8

124

139.6

63 1

184

207.1

HI 2

211

271 7

120 0

65

73.2

33.3

125

140.7

63.7

185

20S.3

94.7

215

27.r, S

120.6

66

74.3

33.8

126

141 9

64.2

180

200 4

95 2

240

277.0

127.1

67

75.4

34.3

127

143. 0

64.7

187

210 5

95.7

217

27S !

127.6

68

76.6

34.8

128

144 1

65.2

188

211 7

248

279 2

128 1

69

77.7

35.3

129

145.2

65.7

1S'.»

212.8

'i,; a

21'."

2S0.3

128 7

70

78.8

35.8

130

146.4

66.2

190

213.9

97.3

250

129.2

108
55

METHODS OF ANALYSIS

Table 7. — Allihn'S Table. — Continued.

[Expressed in milligrams.]

[Chap.

CU-

DEX-

CU-

DEX-

CU-

DEX-

CU-

DEX-

COPPEB

PROUS
OXID

TROSE

COPPER

PROUS
OXID

TROSE

COPPER

PROUS
OXID

TROSE

COPPER

PROUS
OXID

TROSE

251

282.6

129.7

306

344.5

159.8

361

406.4

190.6

416

468.4

222 2

252

283.7

130.3

307

345.6

160.4

362

407.6

191.1

417

469.5

222 8

253

284.8

130.8

308

346.8

160.9

363

408.7

191.7

418

470.6

223.3

254

286.0

131.4

309

347.9

161.5

364

409.8

192.3

419

471.8

223 9

255

287.1

131.9

310

349.0

162.0

365

410.9

192 9

420

472.9

224.5

256

288.2

132.4

311

350.1

162.6

366

412.1

193.4

421

474.0

225 1

257

289.3

133.0

312

351.3

163.1

367

413.2

194.0

422

475.6

225 7

258

290.5

133.5

313

352.4

163.7

368

414.3

194.6

423

476.2

226 3

259

291.6

134.1

314

353.5

164.2

369

415.4

195.1

424

477 4

226.9

260

292.7

134.6

315

354.6

164.8

370

416.6

195.7

425

478.5

227.5

261

293.8

135.1

316

355.8

165.3

371

417.7

196.3

426

479 6

228.0

262

295.0

135.7

317

356.9

165 9

372

418.8

196.8

427

480.7

228.6

263

296.1

136.2

318

358.0

166.4

373

420.0

197.4

428

481 9

229 2

264

297.2

136.8

319

359.1

167.0

374

421.1

198.0

429

483. 0

229 8

265

298.3

137.3

320

360.3

167.5

375

422.2

198.6

430

484.1

230.4

266

299.5

137.8

321

361.4

168.1

376

423.3

199.1

431

485 3

231.0

267

300.6

138.4

322

362.5

168.6

377

424.5

199.7

432

486.4

231.6

268

301.7

138.9

323

363.7

169.2

378

425.6

200.3

433

487.5

232.2

269

302.8

139.5

324

364.8

169.7

379

426.7

200.8

434

488.6

232.8

270

304.0

140.0

325

365.9

170.3

380

427.8

201.4

435

489.7

233.4

271

305.1

140.6

326

367.0

170.9

381

429 0

202.0

436

490.9

233.9

272

306.2

141.1

327

368.2

171.4

382

430.1

202.5

437

492.0

234.5

273

307.3

141.7

328

369.3

172.0

383

431.2

203.1

438

493.1

235.1

274

308.5

142.2

329

370.4

172.5

384

432.3

203.7

439

494.3

235 7

275

309.6

142.8

330

371.5

173.1

385

433.5

204.3

440

495.4

236.3

276

310.7

143.3

331

372.7

173.7

386

434.6

204.8

441

496.5

236.9

277

311.9

143.9

332

373.8

174.2

387

435.7

205.4

442

497.6

237 5

278

313.0

144.4

333

374.9

174.8

388

436.8

206.0

443

498.8

233.1

279

314 1

145.0

334

376.0

175.3

389

438.0

205 5

444

499.9

238 7

280

315.2

145.5

335

377.2

175.9

390

439.1

207.1

445

501.0

239.3

281

316.4

146.1

336

378.3

176.5

391

440.2

207.7

446

502.1

239.8

282

317.5

146.6

337

379.4

177.0

392

441.3

208.3

447

503.2

240 4

283

318.6

147.2

338

380.5

177.6

393

442.4

208.8

448

504.4

241 0

284

319 7

147.7

339

381.7

178.1

394

443.6

209.4

449

505 . 5

241.6

285

320.9

148.3

340

382.8

178.7

395

444.7

210 0

450

506 6

242.2

286

322.0

148.8

341

383.9

179.3

396

445.9

210.6

451

507.8

242.8

287

323 1

149 4

342

385.0

179.8

397

447.0

211.2

452

508.9

243.4

288

324.2

149.9

343

386.2

180.4

398

448.1

211 7

453

510.0

244.0

289

325.4

150.5

344

387.3

180.9

399

449.2

212.3

454

511.1

244 6

290

326.5

151.0

345

388. 4

181.5

400

450 3

212.9

455

512.3

245.2

291

327.4

151.6

346

389.6

182.1

401

451.5

213.5

456

513.4

245.7

292

328.7

152.1

347

390.7

182.6

402

452.6

214.1

457

514 5

246.3

293

329.9

152.7

348

391.8

183.2

403

453.7

214.6

458

515 6

246.9

294

331.0

153.2

349

392 9

183.7

404

454.8

215.2

459

516.8

247.5

295

332.1

153.8

350

394.0

184.3

405

456.0

215.8

460

517 9

248.1

296

333.3

154.3

351

395.2

184.9

406

457.1

216.4

461

519.0

24> 7

297

334.4

154.9

352

396.3

185.4

407

458.2

217.0

462

520 1

249 3

298

335.5

155.4

353

397.4

186.0

408

459.4

217.5

463

521.3

249.9

299

336.6

156.0

354

398 6

186.6

409

460.5

218.1

300

337.8

156.5

355

399.7

187.2

410

461.6

218.7

301

338.9

157.1

356

400.8

187.7

411

462.7

219.3

302

340.0

157.6

357

401 9

188.3

412

463.8

219 9

303

341.1

158.2

353

403.1

188 9

413

465.0

220 4

304

342 3

158.7

359

401.2

189.4

414

466.1

221.0

305

343 4

159 3

360

405 3

191 0

415

467 2

221.6

viii] foods and feeding stuffs 109

56 *edb

Proceed as directed ui
by the following factors:

56 REDUCING SUGARS OTHER THAN DEXTROSE.

Proceed as directed under 54 and multiply the weight of dextrose found in 55

Levulose, 1.093;
Invert sugar, 1.046;
Arabinose, 0.969;
Xylose, 1.017;

Galactose, 1.114.

Total Sugars.11
(Applicable to cattle foods.)
57 PREPARATION OF SOLUTION.

Place 12 grams of the material in a 300 cc. graduated flask, if the substance has an
acid reaction add 1-3 grams of calcium carbonate, and boil on a steam bath fori hour
with 150 cc. of 50% alcohol by volume, using a small funnel in the neck of the flask
to condense the vapor. Cool, and allow the mixture to stand several hours, prefer-
ably overnight. Make up to volume with neutral 95% alcohol, mix thoroughly,
allow to settle, transfer 200 cc. to a beaker with a pipette, and evaporate on a steam
bath to a volume of 20-30 cc.

Do not evaporate to dryness, a little alcohol in the residue doing no harm. Trans-
fer to a 100 cc. graduated flask, and rinse the beaker thoroughly with water, adding
the rinsings to the contents of the flask. Add enough saturated neutral lead acetate
solution to produce a flocculent precipitate, shake thoroughly and allow to stand 15
minutes. Make up to the mark with water, mix thorough'y, and filter through a
dry filter. Add sufficient anhydrous sodium carbonate to the filtrate to precipitate
all the lead, again filter through a dry paper and test the filtrate with a little anhy-
drous sodium carbonate to make sure that all the lead has been removed.

58 DETERMINATION OF REDUCING SUGARS.

Proceed as directed under 26 or 29-34 respectively, employing the Soxhlet
modification of Fehling's solution and using 25 cc. of the solution (representing 2
grams of the sample), prepared as directed in 57. Express the results as dextrose
or invert sugar.

59 SUCROSE.

Introduce 50 cc. of the solution, prepared as directed in 57, into a 100 cc. gradu-
ated flask, add a piece of litmus paper, neutralize with acetic acid, add 5 cc. of con-
centrated hydrochloric acid and allow the inversion to proceed at room temperature
as directed under 14 or 18. When inversion is complete, transfer the solution to a
beaker, neutralize with sodium carbonate, return the solution to tb.3 100 cc. flask,
dilute to the mark with water, filter if necessary and determine reducing sugars in
50 cc. of the solution (representing 2 grams of the sample) as directed in 58. and
calculate the results as invert sugar. Subtract the per cent of reducing sugars be-
fore inversion from the per cent of total sugar after inversion, both calculated as
invert sugar, and multiply the difference by 0.95 to obtain the per cent of sucrose
present.

Since the insoluble material of grain or cattle food occupies some space in the
flask as originally made up, it is necessary to correct for this volume. Results
of a large number of determinations on various materials have shown the average
volume of 12 grams of material to be 9 CC, and therefore to obtain the true amount
of sugars present all results must be multiplied by the factor 0.97.

110 METHODS OF ANALYSIS [Chap.

STARCH.

60 Direct Acid Hydrolysis {Modified Sachsse Method). — Official.

(In this method there will be included as starch the pentosans and other carbo-
hydrate bodies present which undergo hydrolysis and conversion into reducing
sugars on boiling with hydrochloric acid.)

Stir a quantity of the sample, representing 2.5-3 grams of the dry material, in a
beaker with 50 cc. of cold water for an hour. Transfer to a filter and wash with
250 cc. of cold water. Heat the insoluble residue for 2\ hours with 200 cc. of water
and 20 cc. of hydrochloric acid (sp. gr. 1.125) in a flask provided with a reflux con-
denser. Cool, and nearly neutralize with sodium hydroxid. Complete the volume
to 250 cc, filter, and determine the dextrose in an aliquot of the filtrate as directed
under 52 or 54. The weight of the dextrose obtained multiplied by 0.90 gives the
weight of starch.

The factor 0.9 is the theoretical ratio between starch and glucose but, according
to Noyes12and other investigators, the factor 0.93 more nearly approaches the actual
yield.

Diastase Method with Subsequen' Acid Hydrolysis. — Tentative.

61 REAGENT.

Malt extract. — Digest 10 grams of fresh, finely ground malt for 2-3 hours at or-
dinary temperature with 200 cc. of water and filter. Determine the amount of dex-
trose in a given quantity of the filtrate after boiling with acid, etc., as in the starch
determination, and make the proper correction in the subsequent determination.

62

DETERMINATION.

Extract a convenient quantity of the substance (ground to an impalpable powder
and representing 4-5 grams of the dry material) on a hardened filter with 5 successive
portions of 10 cc. of ether; wash with 150 cc. of 10% alcohol and then with a little strong
alcohol. Place the residue in a beaker with 50 cc. of water, immerse the beaker in boil-
ing water, and stir constantly for 15 minutes or until all the starch is gelatinized ; cool
to55°C, add 20 cc. of malt extract, and maintain at this temperature for an hour.
Heat again to boiling for a few minutes, cool to55°C, add 20 cc. of malt extract, and
maintain at this temperature for an hour or until the residue treated with iodin shows
no blue color upon microscopic examination. Cool, make up directly to 250 cc, and
filter. Place 200 cc. of the filtrate in a flask with 20 cc of hydrochloric acid (sp. gr.
1.125); connect with a reflux condenser and heat in a boiling water bath for 2? hours.
Cool, nearly neutralize with sodium hydroxid solution, finish the neutralization
with sodium carbonate solution, and make up to 500 cc. Mix the solution well, pour
through a dry filter, and determine the dextrose in an aliquot as directed under
52 or 54. Conduct a blank determination upon the same volume of the malt
extract as used upon the sample and correct the weight of reduced copper accord-
ingly. The weight of the dextrose obtained multiplied by 0.90 gives the weight of
starch.

PENTOSANS.— TENTATIVE.

63 REAGENT.

Phloroglucin.— Dissolve a small quantity of the phloroglucin in a few drops of
acetic anhydrid, heat almost to boiling, and add a few drops of concentrated sul-

VIII] FOODS AND FEEDING STUFFS 111

phuric acid. A violet color indicates the presence of diresorcin. A phloroglucin
which gives more than a faint coloration may be purified by the following method:
Heat in a beaker about 300 cc. of hyd ochloric acid (sp. gr. 1.06) and 11 grams of
commercial phloroglucin, added in small quantities at a time, stirring constantly
until it has almost entirely dissolved. Pour the hot solution into a sufficient quan-
tity of the same hydrochloric acid (cold) to make the volume 1503 cc. Allow it
to stand at least overnight, preferably several days, to permit the diresorcin to
crystallize out. Filter immediately before using. A yellow tint does not inter-
fere with its usefulness. In using it, add the volume containing the required amount
to the distillate.

64 DETERMINATION.

Place a quantity of the material, 2-5 grams, chosen so that the weight of phloro-
glucid obtained shall not exceed 0.300 gram, in a 300 cc. distillation flask, together
with 100 cc. of 12% hydrochloric acid (sp. gr. 1.06), and several pieces of recently
heated pumice stone. Place the flask on a wire gauze, connect with a condenser,
and heat, rather gently at first, and regulate so as to distil over 30 cc. in about 10
minutes, the distillate passing through a small filter paper. Rep'ace the 30 cc.
distilled by a like quantity of the dilute acid, added by means of a separatory funnel
in such a manner as to wash down the particles adhering to the sides of the flask, and
continue the process until the distillate amounts to 360 cc. To the total distillate
add gradually a quantity of phloroglucin dissolved in 12% hydrochloric acid and
stir thoroughly the resulting mixture. The amount of phloroglucin used should be
about double that of the furfural expected. The solution turns first yellow, then
green, and very soon an amorphous greenish precipitate appears, which grows
darker rapidly, till it becomes finally almost black. Make the solution up to 400
cc. with 12% hydrochloric acid, and allow to stand overnight.

Filter the amorphous black precipitate into a tared Gooch crucible through an
asbestos mat, wash carefully with 150 cc. of water in such a way that the water is
not entirely removed from the crucible until the very last, then dry for 4 hours at
the temperature of boiling water, cool and weigh in a weighing bottle, the increase
in weight being reckoned as furfural phloroglucid. To calculate the furfural, pen-
tose, or pentosan from the phloroglucid, use the following formulas given by Krober:

(1) For a weight of phloroglucid, designated by "a" in the following formulas,
under 0.03 gram,

Furfural = (a + 0.0052) X 0.5170.

Pentoses = (a + 0.0052) X 1.0170.

Pentosans = (a + 0.0052) X 0.8949.

In the above and also in the following formulas, the factor 0.0052 represents the
weight of phloroglucid which remains dissolved i i the 403 cc. of acid solution.

(2) For a weight of phloroglucid "a" over 0.300 gram,

Furfural = (a + 0.0052) X 0.5180.

Pentoses = (a + 0.0052) X 1.0026.

Pentosans = (a + 0.0052) X 0.8824.

For a weight of phloroglucid "a" between 0.03 an 1 0.300 gram use Krober's
table, 65, or the following formulas in which the factors were calculated from
Krober's tables by C. A. Browne, "

Furfural = (a + 0.0052) X 0.5185.

Pentoses = (a + 0.0052) X 1.0075.

Pentosans = (a + 0.0052) X 0.S866.

112
65

methods of analysis

Table 8.— Krober-s Table.14
For Determining Pentoses and Pentosans.

[Chap.

[E

tpressed in grams.)

FURFURAL
PHLOROGLCCID

FURFURAL

tRABINOSE

ARAB AN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

0.030

0.0182

0.0391

0.0344

0.0324

0.0285

0.0358

0.0315

0.031

0.0188

0.0402

0.0354

0.0333

0.0293

0.0368

0.0324

0.032

0.0193

0.0413

0.0363

0.0342

0.0301

0.0378

0.0333

0.033

0.0198

0.0424

0.0373

0.0352

0.0309

0.0388

0.0341

0.034

0.0203

0.0435

0.0383

0.0361

0.0317

0.0398

0.0350

0.035

0.0209

0.0446

0.0393

0.0370

0.0326

0.0408

0.0359

0.036

0.0214

0.0457

0.0402

0.0379

0.0334

0.0418

0.0368

0.037

0.0219

0.046S

0.0412

0.03S8

0.0342

0.0428

0.0377

0.038

0.0224

0.0479

0.0422

0.0398

0.0350

0.0439

0.0386

0.039

0.0229

0.0490

0.0431

0.0407

0.0358

0.0449

0.0395

0.040

0.0235

0.0501

0.0441

0.0416

0.0366

0.0459

0.0404

0.041

0.0240

0.0512

0.0451

0.0425

0.0374

0.0469

0.0413

0.042

0.0245

0.0523

0.0460

0.0434

0.0382

0.0479

0.0422

0.043

0.0250

0.0534

0.0470

0.0443

0.0390

0.0489

0.0431

0.044

0.0255

0.0545

0.04S0

0.0452

0.0398

0.0499

0.0440

0.045

0.0260

0.0556

0.0490

0.0462

0.0406

0.0509

0.0448

0.046

0.0266

0.0567

0.0499

0.0471

0.0414

0.0519

0.0457

0.047

0.0271

0.057S

0.0509

0.0480

0.0422

0.0529

0.0466

0.048

0.0276

0.05S9

0.0519

0.0489

0.0430

0.0539

0.0475

0.049

0 .0281

0.0600

0.052S

0.0498

0.0438

0.0549

0.04S4

0.050

0.0286

0.0611

0.0538

0.0507

0.0446

0.0559

0.0492

0.051

0.0292

0.0622

0.0548

0.0516

0.0454

0.0569

0.0501

0.052

0.0297

0.0633

0.0557

0.0525

0.0462

0.0579

0.0510

0.053

0.0302

0.0644

0.0567

0.0534

0.0470

0.0589

0.0519

0.054

0.0307

0.0655

0.0576

0.0543

0.0478

0.0599

0.0528

0.055

0.0312

0.0666

0.0586

0.0553

0.04S6

0.0610

0.0537

0.056

0.0318

0.0677

0.0596

0.0562

0.0494

0.0620

0.0546

0.057

0.0323

0.0688

0.0605

0.0571

0.0502

0.0630

0.0555

0.058

0.0328

0.0699

0.0615

0.05S0

0.0510

0.0640

0.0564

0.059

0.0333

0.0710

0.0624

0.05S9

0.0518

0.0650

0.0573

0.060

0.0338

0.0721

0.0634

0.059S

0.0526

0.0660

0.0581

0.061

0.0344

0.0732

0.0644

0.0607

0.0534

0.0670

0.0590

0.062

0.0349

0.0743

0.0653

0.0616

0.0542

0.06S0

0.0599

0.063

0.0354

0.0754

0.0663

0.0626

0.0550

0.0690

0.0608

0.064

0.0359

0.0765

0.0673

0.0635

0.055S

0.0700

0.0617

0.065

0.0364

0.0776

0.0683

0.0644

0.0567

0.0710

0.'

0.066

0.0370

0.0787

0.0692

0.0653

0.0575

0.0720

0.0634

0.067

0.0375

0.0798

0.0702

0.0662

0.0583

0.0730

0.0643

0.068

0.0380

0.0809

0.0712

0.0672

0.0591

0.0741

0.0652

0.069

0.03S5

0.0S20

0.0721

0.06S1

0.0599

0.0751

0.0661

0.070

0.0390

0.0831

0.0731

0.0690

0.1 1

0.0761

0.0670

0.071

0.0396

0.0842

0.0741

0.0699

0.0615

0.0771

0.0679

0.072

0.0401

0.0853

0.0750

0.0708

0.0623

71

0.0688

0.073

0.0406

0.1 864

0.0760

0 0717

0.0631

0.0791

0.0697

0.074

0.0411

0.0875

0.0770

0.0726

0.0639

0.0S01

0.0706

VIII]
65

FOODS AND FEEDING STUFFS

Table 8.— Krober'S Table. — Continued.

[Expressed in grams]

113

FURFURAL
PHLOROQl.UCID

FURFURAL

ARABINOSE

ARABAN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

0.075

0.0416

0.0886

0.0780

0.0736

0.0647

0.0811

0.0714

0.076

0.0422

0.0897

0.0789

0.0745

0.0655

0.0821

0.0722

0.077

0.0427

0.0908

0.0799

0.0754

0.0663

0.0831

0.0731

0.078

0.0432

0.0919

0.0809

0.0763

0.0671

0.0841

0.0740

0.079

0.0437

0.0930

0.0818

0.0772

0.0679

0.0851

0.0749

0.080

0.0442

0.0941

0.0828

0.0781

0.0687

0.0861

0.0758

0.081

0.0448

0.0952

0.0838

0.0790

0.0695

0.0871

0.0767

0.082

0.0453

0.0963

0.0847

0.0799

0.0703

0.0881

0.0776

0.083

0.0458

0.0974

0.0857

0.0808

0.0711

0.0891

0.0785

0.084

0.0463

0.0985

0.0867

0.0817

0.0719

0.0901

0.0794

0.085

0.0468

0.0996

0.0877

0.0827

0.0727

0.0912

0.0803

0.086

0.0474

0.1007

0.0886

0.0836

0.0735

0.0922

0.0812

0.087

0.0479

0.1018

0.0896

0.0845

0.0743

0.0932

0.0821

0.088

0.0484

0.1029

0.0906

0.0854

0.0751

0.0942

0.0830

0.089

0.0489

0 . 1040

0.0915

0.0863

0.0759

0.0952

0.0838

0.090

0.0494

0.1051

0.0925

0.0872

0.0767

0.0962

0.0847

0.091

0.0499

0.1062

0.0935

0.0881

0.0775

0.0972

0.0856

0.092

0.0505

0 . 1073

0.0944

0.0890

0.0783

0.0982

0.0865

0.093

0.0510

0.1084

0.0954

0.0900

0.0791

0.0992

0.0874

0.094

0.0515

0 . 1095

0.0964

0.0909

0.0800

0.1002

0.0S83

0.095

0.0520

0.1106

0.0974

0.0918

0.0808

0.1012

0.0891

0.096

0.0525

0.1117

0.0983

0.0927

0.0816

0.1022

0.0899

0.097

0.0531

0.1128

0.0993

0.0936

0.0824

0.1032

0.0908

0.098

0.0536

0.1139

0.1003

0.0946

0.0832

0.1043

0.0917

0.099

0.0541

0.1150

0.1012

0.0955

0.0840

0.1053

0.0926

0.100

0.0546

0.1161

0.1022

0.0964

0.0S48

0.1063

0.0935

0.101

0.0551

0.1171

0.1032

0.0973

0.0856

0.1073

0.0944

0.102

0.0557

0.1182

0.1041

0.0982

0.0864

0.1083

0.0953

0.103

0.0562

0.1193

0.1051

0.0991

0.0872

0 . 1093

0.0962

0.104

0.0567

0 . 1204

0.1060

0.1000

0.0880

0.1103

0.0971

0.105

0.0572

0.1215

0.1070

0.1010

0.088S

0.1113

0.0979

0.106

0.0577

0.1226

0.1080

0.1019

0.0806

0.1123

0.0988

0.107

0.0582

0.1237

0.1 0S9

0.1028

0.0004

0.1133

0.0997

0.108

0.0588

0.1248

0.1099

0.1037

0.0912

0.1143

0.1006

0.109

0.0593

0.1259

0.1108

0.1046

0.0920

0.1153

0.1015

0.110

0.0598

0.1270

0.1118

0.1055

0.0928

0.1163

0.1023

0.111

0.0603

0.1281

0.1128

0.1064

0.0936

0.1173

0.1032

0.112

0.0608

0.1292

0.1137

0.1073

0.0914

0.1183

0.1041

0.113

0.0614

0.1303

0.1147

0.1 082

0.0952

0.1193

0.1050

0.114

0.0619

0.1314

0.1156

0.1091

0.0960

0.1203

0.1059

0.115

0.0624

0.1325

0.1166

0.1101

o.ooas

0.1213

0.1067

0.116

0.0629

0.1336

0.1176

0.1110

0.0976

0.1223

0.1076

0.117

0.0034

0.1347

0.1185

0.1119

0.09S1

0.1233

0.1086

0.118

0.0640

0.1358

0.1195

0.1128

0.0992

0.1243

0.1094

0.119

0.0645

0.1369

0.1204

0.1137

0.1000

0.1253

0.1103

114
65

METHODS OF ANALYSIS

Table 8.— Krober*s Table.— Continued.

[Expressed in grams.]

[Chap.

FURFURAL
PHLOROGLUCID

FURFURAL

ARABINOSE

ARABAN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

0.120

0.0650

0.1380

0.1214

0.1146

0.1008

0.1263

0.1111

0.121

0.0655

0.1391

0.1224

0.1155

0.1016

0.1273

0.1120

0.122

0.0660

0 . 1402

0.1233

0.1164

0.1024

0.1283

0.1129

0.123

0.0665

0.1413

0.1243

0.1173

0 . 1032

0.1293

0.1138

0.124

0.0671

0.1424

0.1253

0.1182

0.1040

0.1303

0.1147

0.125

0.0676

0.1435

0.1263

0.1192

0 . 1049

0.1314

0.1156

0.126

0.0681

0.1446

0.1272

0.1201

0.1057

0.1324

0.1165

0.127

0.06S6

0.1457

0 . 1282

0.1210

0 . 1065

0.1334

0.1174

0.128

0.0691

0.1468

0.1292

0.1219

0.1073

0.1344

0.1183

0.129

0.0697

0.1479

0.1301

0.1228

0.1081

0.1354

0.1192

0.130

0.0702

1490

0.1311

0 . 1237

0.1089

0.1364

0.1201

0.131

0.0707

0.1501

0.1321

0.1246

0 . 1097

0.1374

0.1210

0.132

0.0712

0.1512

0.1330

0.1255

0.1105

0.1384

0.1219

0.133

0.0717

0.1523

0.1340

0.1264

0.1113

0.1394

0.1227

0.134

0.0723

0.1534

0.1350

0.1273

0.1121

0.1404

0.1236

0.135

0.0728

0.1545

0.1360

0.1283

0.1129

0.1414

0.1244

0.136

0.0733

0.1556

0.1369

0.1292

0.1137

0 . 1424

0.1253

0.137

0.0738

0.1567

0.1379

0.1301

0.1145

0.1434

0.1262

0.138

0.0743

0.1578

0.1389

0.1310

0.1153

0.1444

0.1271

0.139

0.0748

0.1589

0.1398

0.1319

0.1161

0.1454

0.1280

0.140

0.0754

0 . 1600

0.1408

0.1328

0.1169

0.1464

0.1288

0.141

0.0759

0.1611

0.1418

0.1337

0.1177

0.1474

0.1297

0.142

0.0764

0.1622

0.1427

0.1346

0.1185

0.1484

0.1306

0.143

0.0769

0.1033

0.1437

0.1355

0.1193

0.1494

0.1315

0.144

0.0774

0.1644

0.1447

0.1364

0.1201

0 . 1504

0.1324

0.145

0.0780

0.1655

0.1457

0.1374

0.1209

0.1515

0.1333

0.146

0.0785

0.1666

0.1466

0.1383

0.1217

0.1525

0.1342

0.147

0.0790

0.1677

0.1476

0.1392

0.1225

0.1535

0.1351

0.148

0.0795

0.1688

0.1486

0.1401

0.1233

0.1545

0.1360

0.149

0.0800

0.1699

0.1495

0.1410

0.1241

0.1555

0.1369

0.150

0.0805

0.1710

0.1505

0.1419

0.1249

0.1565

0.1377

0.151

0.0811

0.1721

0.1515

0.1428

9 . 1257

0.1575

0.1386

0.152

0.0816

0.1732

0.1524

0.1437

0.1265

0.1585

0.1395

0.153

0.0821

0.1743

0.1534

0.1446

0.1273

0.1595

0.1404

0.154

0.0826

0.1754

0.1544

0.1455

0.1281

0.1605

0.1413

0.155

0.0831

0.1765

0.1554

0.1465

0.1289

0.1615

0.1421

0.156

0.0837

0.1776

0.1563

0.1474

0.1297

0.1625

0.1430

0.157

0.0842

0.1 787

0.1573

0.1483

0.1305

0.1635

0.1439

0.158

0.0847

0.1798

0.1583

0.1492

0.1313

0.1645

0.1448

0.159

0.0852

0.1809

0.1592

0.1501

0.1321

0.1655

0 . 1457

0.160

0.0857

0.1820

0.1602

0.1510

0.1329

0.1665

0.1465

0.161

0.0863

0.1S31

0.1612

0.1519

0.1337

0.1675

0.1474

0.162

0.0868

0.1842

0.1621

0.1528

0.1345

0.1 685

0.1483

0.163

0.0873

0 . 1853

0.1631

0.1537

0.1353

0.1695

0.1492

0.164

0.0878

0.1864

0.1640

0.1546

0.1361

0.1705

0.1501

VIII]

FOODS AND FEEDING STUFFS

115

65

Table 8.— Krober'S Table. — Continued.

[Expressed in grams.]

FURFURAL

FURFURAL

ARABIN03E

ARABAN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

PHI.OROGI.UCID

0.165

0.0883

0 . 1875

0.1650

0.1556

0.1369

0.1716

0.1510

0.166

0.0888

0.1886

0.1660

0.1565

0.1377

0.1726

0.1519

0.167

0.0894

0 . 1897

0.1669

0.1574

0.1385

0.1736

0.1528

0.168

0.0899

0 . 1908

0.1679

0.1583

0.1393

0.1746

0.1537

0.169

0.0904

0.1919

0 . 1688

0 . 1592

0.1401

0.1756

0.1546

0.170

0.0909

0 . 1930

0.1698

0.1601

0.1409

0.1766

0.1554

0.171

0.0914

0.1941

0 . 1708

0.1610

0.1417

0.1776

0.1563

0.172

0.0920

0 . 1952

0.1717

0.1619

0.1425

0 . 1786

0 . 1572

0.173

0.0925

0 . 1963

0 . 1727

0.1628

0.1433

0.1796

0.1581

0.174

0.0930

0.1974

0 . 1736

0.1637

0 . 1441

0.1806

0 . 1590

0.175

0.0935

0 . 1985

0.1746

0.1647

0.1449

0.1816

0.1598

0.176

0.0940

0.1996

0.1756

0.1656

0.1457

0.1826

0.1607

0.177

0.0946

0.2007

0.1765

0.1665

0.1465

0.1836

0.1616

0.178

0.0951

0.2018

0.1775

0 . 1674

0 . 1473

0.1846

0.1625

0.179

0.0956

0.2029

0.1784

0.1683

0.1481

0.1856

0.1634

0.180

0.0961

0.2039

0 . 1794

0.1692

0.1489

0.1 866

0.1642

0.181

0.0966

0.2050

0.1804

0.1701

0.1497

0.1876

0.1651

0.182

0.0971

0.2061

0.1813

0.1710

0.1505

0.1886

0.1660

0.183

0.0977

0.2072

0 . 1823

0.1719

0.1513

0.1896

0.1669

0.184

0.0982

0.2082

0.1832

0 . 1728

0.1521

0.1906

0.1678

0.185

0.0987

0.2093

0 . 1842

0.1738

0.1529

0.1916

0.1686

0.186

0.0992

0.2104

0.1851

0.1747

0.1537

0.1926

0.1695

0.187

0.0997

0.2115

0.1861

0.1756

0.1545

0.1936

0 . 1704

0.188

0.1003

0.2126

0 . 1870

0.1765

0.1553

0.1946

0.1712

0.189

0 . 1008

0.2136

0.1880

0.1774

0.1561

0.1955

0.1721

0.190

0.1013

0.2147

0 . 1889

0.1783

0.1569

0.1965

0.1729

0.191

0.1018

0.2158

0.1899

0.1792

0.1577

0.1975

0.1738

0.192

0.1023

0.2168

0 . 1908

0.1801

0.1585

0.1985

0.1717

0.193

0.1028

0.2179

0.1918

0.1810

0.1593

0.1995

0.1756

0.194

0.1034

0.2190

0.1927

0.1819

0.1601

0.2005

0.1764

0.195

0.1039

0.2201

0.1937

0.1829

0.1609

0.2015

0.1773

0.196

0.1044

0.2212

0.1946

0.1838

0.1617

0.2025

0.17v_'

0.197

0 . 1049

0.2222

0.1956

0 . 1S47

0.1625

0.2035

0.1791

0.198

0 . 1054

0^2233

0 . 1965

0.1856

0.1633

0.2045

0.1S00

0.199

0.1059

0.2244

0.1975

0.1865

0.1641

0.2055

0.1808

0.200

0 . 1065

0.2255

0.1984

0.1874

0.1649

0.2065

0.1817

0.201

0.1070

0.2266

0.1994

0.1883

0.1657

0.2075

0.1826

0.202

0.1075

0.2276

0.2003

0.1892

0.1665

0.2085

0.1835

0.203

0.1080

0.2287

0.2013

0.1901

0.1673

0.2095

0.1844

0.204

0.1085

0.2298

0.2022

0.1910

0.1681

0.2105

0 . 1853

0.205

0.1090

0.2309

0.2032

0.1920

0.1689

0.2115

0.1861

0.206

0.1096

0.2320

0.2041

0.1929

0.1697

0.2125

0.1 S69

0.207

0.1101

0.2330

0.2051

0.1938

0.1705

0.2134

0.1 878

0.208

0.1106

0.2341

0 . 2060

0.1947

0.1713

0.2144

0.1887

0.209

0.1111

0.2352

0.2069

0.1956

0.1721

0.2154

0 . 1S96

116
65

METHODS OF ANALYSIS

Table 8. — Krober's Table.— Continued.

[Expressed in grams.]

[Chap.

FURFURAL
PHLOROQLUCID

FURFURAL

ARABINOSE

ARABAN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

0.210

0.1116

0.2363

0.2079

0.1965

0.1729

0.2164

0.1904

0.211

0.1121

0.2374

0.2089

0.1975

0.1737

0.2174

0.1913

0.212

0.1127

0.2384

0.2098

0.1984

0.1745

0.2184

0.1922

0.213

0.1132

0.2395

0.2108

0.1993

0.1753

0.2194

0.1931

0.214

0.1137

0.2406

0.2117

0.2002

0.1761

0.2204

0.1940

0.215

0.1142

0.2417

0.2127

0.2011

0.1770

0.2214

0.1948

0.216

0.1147

0.2428

0.2136

0.2020

0.1778

0.2224

0.1957

0.217

0.1152

0.2438

0.2146

0.2029

0.1786

0.2234

0.1966

0.218

0.1158

0.2449

0.2155

0.2038

0.1794

0.2244

0.1974

0.219

0.1163

0.2460

0.2165

0.2047

0.1802

0.22.54

0 . 1983

0.220

0.1168

0.2471

0.2174

0.2057

0.1810

0.2264

0 . 1992

0.221

0.1173

0.2482

0.2184

0.2066

0.1818

0.2274

0.2001

0.222

0.1178

0.2492

0.2193

0.2075

0.1826

0.2284

0.2010

0.223

0.1183

0.2503

0.2203

0.2084

0.1834

0.2204

0.2019

0.224

0.1189

0.2514

0.2212

0.2093

0 . 1842

0.2304

0.2028

0.225

0.1194

0.2525

0.2222

0.2102

0.1850

0.2314

0.2037

0.226

0.1199

0.2536

0.2232

0.2111

0.1858

0.2324

0.2046

0.227

0.1204

0.2546

0.2241

0.2121

0 . 1866

0.2334

0.2054

0.228

0.1209

0.2557

0.2251

0.2130

0.1874

0.2344

0.2^63

0.229

0.1214

0.2568

0.2260

0.2139

0.1882

0.2354

0.2072

0.230

0.1220

0.2579

0.2270

0.2148

0.1890

0.2364

0.2081

0.231

0.1225

0.2590

0.2280

0.2157

0.1898

0.2374

0.2089

0.232

0.1230

0.2600

0.2289

0.2166

0.1906

0.23S3

0 . 2097

0.233

0.1235

0.2611

0.2299

0.2175

0.1914

0.2393

0.2106

0.234

0.1240

0.2622

0.2308

0.2184

0.1922

0.2403

0.2115

0.235

0.1245

0.2633

0.2318

0.2193

0.1930

0.2413

0.2124

0.236

0.1251

0.2644

0.2327

0.2202

0 . 1938

0.2423

0.2132

0.237

0 . 1256

0.2654

0.2337

0.2211

0.1946

0.2433

0.2141

0.238

0.1261

0.2665

0.2346

0.2220

0.1954

0.2443

0.2150

0.239

0.1266

0.2676

0.2356

0.2229

0.1962

0.2453

0.2159

0.240

0.1271

0.2687

0.2365

0.2239

0.1970

0.2463

0.2168

0.241

0.1276

0.2698

0.2375

0.2248

0.1978

0.2473

0.2176

0.242

0.1281

0.2708

0.2384

0.2257

0.1986

0.2483

0.21*5

0.243

0.1287

0.2719

0.2394

0.2266

0.1994

0.2493

0.2194

0.244

0.1292

0.2730

0.2403

0.2275

0.2002

0.2503

0.2203

0.245

0.1297

0.2741

0.2413

0.22S4

0.2010

0.2513

0.2212

0.246

0.1302

0.2752

0.2422

0.2293

0.2018

0.2523

0 . 2220

0.247

0.1307

0.2762

0.2432

0.2302

0.2026

0.2533

0.2229

0.248

0.1312

0.2773

0.2441

0.2311

0.2034

0.2543

0.2238

0.249

0.1318

0.2784

0.2451

0.2320

0.2042

0.2553

0.2217

0.250

0 . 1323

0.2795

0.2460

0.2330

0.2050

0.2563

0.2256

0.251

0.1328

0.2806

0.2470

0.2339

0.205S

0.2573

0.2264

0.252

0.1333

0.2816

0.2479

0.2348

0.2066

0.2582

0.2272

0.253

0.1338

0.2827

0.2489

0.2357

0.2074

0.2592

0.2281

0.254

0.1343

0.2838

0.2498

0.2366

0.2082

0.2602

0.2290

VIII]
65

FOODS AND FEEDING STUFFS

Table 8.— Krober-s Table.— Continued.

117

[Expressed in

grams.]

FURFURAL
PHLOROQLUCID

FURFURAL

ARABIN08E

ARABAN

XYLOSE

XYLAN

PENTOSE

PENTOSAN

0.255

0.1349

0.2849

0.2508

0.2375

0.2090

0.2612

0.2299

0.256

0.1354

0.2860

0.2517

0.2384

0.2098

0.2622

0.2317

0.257

0.1359

0.2870

0.2526

0.2393

0.2106

0.2632

0.2316

0.258

0.1364

0.28S1

0.2536

0.2402

0.2114

0.2642

0.2325

0.259

0.1369

0.2892

0.2545

0.2411

0.2122

0.2652

0.2334

0.260

0.1374

0.29"3

0.2555

0.2420

0.2130

0.2662

0.2342

0.261

0.1380

0.2914

0.2565

0.2429

0.2138

0.2672

0.2351

0.262

0.1385

0.2924

0.2574

0.2438

0.2146

0.2681

0.2359

0.263

0.1390

0.2935

0.2584

0.2447

0.2154

0.2691

0.2368

0.264

0.1395

0.2946

0.2593

0.2456

0.2162

0.2701

0.2377

0.265

0.1400

0.2957

0.26"3

0.2465

0.2170

0.2711

0.2385

0.266

0.1405

0.2968

0.2612

0.2474

0.2178

0.2721

0.2394

0.267

0.1411

0.2978

0.2622

0.2483

0.2186

0.2731

0.2403

0.268

0.1416

0.2989

0.2631

0.2492

0.2194

0.2741

0.2412

0.269

0.1421

0.3000

0.2641

0.2502

0.2202

0.2751

0.2421

0.270

0.1426

0.3011

0.2650

0.2511

0.2210

0.2761

0.2429

0.271

0.1431

0.3022

0.2660

0.2520

0.2218

0.2771

0.2438

0.272

0.1436

0.3132

0.2669

0.2529

0.2226

0.2781

0.2447

0.273

0.1442

0.3143

0.2679

0.2538

0.2234

0.2791

0.2456

0.274

0.1447

0.3054

0.2688

0.2547

0.2242

0.2801

0.2465

0.275

0.1452

0.3065

0.2698

0.2556

0.2250

0.2811

0.2473

0.276

0.1457

0.3076

0.2707

0.2565

0.2258

0.2821

0.2482

0.277

0.1462

0.3086

0.2717

0.2574

0.2266

0.2830

0.2490

0.278

0.1467

0.3097

0.2726

0.2583

0.2274

0.2840

0.2499

0.279

0.1473

0.3108

0.2736

0.2592

0.2282

0.2850

0.2508

0.280

0.1478

0.3119

0.2745

0.2602

0.2290

0.2861

0.2517

0.281

0.1483

0.3130

0.2755

0.2611

0.2298

0.2871

0.2526

0.282

0.1488

0.3140

0.2764

0.2620

0.2306

0.2880

0.2534

0.283

0.1493

0.3151

0.2774

0.2629

0.2314

0.2S90

0.2543

0.284

0.1498

0.3162

0.2783

0.2638

0.2322

0.2900

0.2552

0.285

0.1504

0.3173

0.2793

0.2647

0.2330

0.2910

0.2561

0.286

0.1509

0.3184

0.2802

0.2656

0.233S

0.2920

0.2570

0.287

0.1514

0.3194

0.2812

0.2665

0.2346

0.2930

0.2:>7S

0.288

0.1519

0.3205

0.2821

0.2674

0.2354

0.2940

0.2587

0.289

0.1524

0.3216

0.2831

0.2683

0.2362

0.2950

0.2596

0.290

0.1529

0.3227

0.2840

0.2693

0.2370

0.2960

0.2605

0.291

0.1535

0.3238

0.2850

0.2702

0.2378

0.2970

0.2614

0.292

0.1540

0.3248

0.2859

0.2711

0.2386

0.298 1

0.2622

0.293

0.1545

0.3259

0.2868

0.2720

0.2394

0.2990

0.2631

0.294

0.1550

0.3270

0.2878

0.2729

0.2402

0.3000

0.2610

0.295

0.1555

0.3281

0.2887

0.2738

0.2410

0.3010

0.2649

0.296

0.1560

0.3292

0.2897

0.2747

0.2 lis

0.3020

0.2658

0.297

0.1566

0.3302

0.2906

0.2756

0.2426

0.3030

0.2666

0.298

0.1571

0.3313

0.2916

0.2765

0.2434

(i 3

0 2675

0.299

0.1576

0.3324

0.2925

0.2774

0.2442

0.3050

0.2684

0.300

0.1581

0.3335

0.2935

0.27S4

0.L

A ^gfl

0.2693

118 METHODS OF ANALYSIS [Chap.

66 GALACTAN.— TENTATIVE.

Extract a convenient quantity of the substance, representing 2.5-3 grams of the
dry material, on a hardened filter with 5 successive portions of 10 cc. of ether, place
the extracted residue in a beaker, about 5.5 cm. in diameter and 7 cm. deep, together
with 60 cc. of nitric acid of 1.15 sp. gr., and evaporate the solution to exactly one
third its volume in a water bath at a temperature of 94°-96°C. After standing 24
hours, add 10 cc. of water to the precipitate, and allow it to stand another 24 hours.
The mucic acid has in the meantime crystallized, but it is mixed with considerable
material only partially oxidized by the nitric acid. Filter the solution through filter
paper, wash with 30 cc. of water to remove as much of the nitric acid as possible,
and replace the filter and contents in the beaker. Add 30 cc. of ammonium car-
bonate solution, consisting of 1 part ammonium carbonate, 19 parts water, and 1
part strong ammonium hydroxid, and heat the mixture on a water bath, at 80°C,
for 15 minutes, with constant stirring. The ammonium carbonate takes up the
mucic acid, forming soluble ammonium mucate. Wash the filter paper and con-
tents several times with hot water by decantation, passing the washings through a
filter paper, to which finally transfer the material and thoroughly wash. Evapo-
rate the filtrate to dryness over a water bath, avoiding unnecessary heating which
causes decomposition, add 5 cc. of nitric acid of 1.15 sp. gr., stir thoroughly the
mixture and allow to stand for 30 minutes. The nitric acid decomposes the am-
monium mucate, precipitating the mucic acid; collect this on a tared filter or Gooch,
wash with 10-15 cc. of water, then with 60 cc. of alcohol, and a number of times
with ether, dry at the temperature of boiling water for 3 hours, and weigh. Mul-
tiply the weight of the mucic acid by 1.33, which gives galactose, and multiply this
product by 0.9 which gives galactan.

CRUDE FIBER.— OFFICIAL.

67 REAGENTS.

(a) 1.25% sulphuric acid solution. — Exact strength, determined by titration.

(b) 1.25% sodium hydroxid solution. — Exact strength, determined by titration.

68 DETERMINATION.

Extract a quantity of the substance, representing about 2 grams of the dry
materia', with ordinary ether, or use the residue from the determination of the ether
extract. To this residue in a 500 cc. flask add 200 cc. of boiling 1.25% sulphuric
acid; connect the flask with an inverted condenser, the tube of which passes only a
short distance beyond the rubber stopper into the flask, or simply cover a tall coni-
cal flask, which is well suited for this determination, with a watch glass or short
stemmed funnel, boil at once and cont'nue boiling gently for 30 minutes. A blast
of air conducted nto the flask will serve to reduce the frothing of the liquid. Filter
through linen and wash with boiling water until the washings are no longer acid;
rinse the substance back into the flask with 200 cc. of boiling, 1.25% solution of
sodium hydroxid, free or nearly free from sodium carbonate boil at once, and con-
tinue boiling gently for 30 minutes as directed above for the treatment with acid,
filter at once rapidly, and wash with boiling water until the washings are neutral.
The last filtration may be performed upon a Gooch crucible, a linen filter, or a tared
filter paper. If a linen filter is used, rinse the crude fiber, after washing is completed,
into a flat-bottomed platinum dish by means of a jet of water; evaporate to dryness
on a steam bath, dry to constant weight at 110°C., weigh, incinerate completely,
and weigh again. The loss in weight is considered to be crude fiber. If a tared filter

VIII] FOODS AND FEEDING STUFFS 119

paper is used, weigh in a weighing bottle. In any case the crude fiber after drying
to constant weight at 110°C. must be incinerated and the amount of the ash deducted
from the original weight.

69 WATER-SOLUBLE ACIDITY OF FEEDS.— TENTATIVE.

Weigh 10 grams of the sample into a shaking bottle, add 200 cc. of water, and
shake for 15 minutes. Filter the extract through a folded filter and take a 20 cc.
aliquot (equivalent to 1 gram of sample) for the titration. Dilute with 50 cc. of
water and titrate with N/10 sodium hydroxid, using phenolphthalein as indicator.

In reporting the acidity of feeds, state the results in terms of cc. of X/10 sodium
hydroxid required for neutralization.

BIBLIOGRAPHY.

1 Z. Ver. Zucker-Ind., 1900, 37 (I): 357; 1913, 63 (I): 25; J. Ind. Eng. Chem.,
1913,5: 167.

2 J. Am. Chem. Soc. 1914, 36: 1566.

3 Ibid., 1906, 28: 663; 1907, 29: 541.
<Ibid., 1902, 24: 1082.

6 Z. Rubenzucker-Ind., 1885, 35 (N. F.22) : 1012.

6 Ibid., 1889, 39 (N. F. 26) : 734.

7 Ibid., 1879, 29 (N. F. 16) : 1034.

8Wein. Tables for the Quantitative Estimation of the Sugars. Translated bv
Frew. 1896, p. 26.
9 Ibid., p. 33.

10 Z. Rubenzucker-Ind., 1882, 32 (N. F. 19) : 606, 865.

11 U.S. Bur. Chem. Circ. 71.

12 J. Am. Chem. Soc, 1904. 26: 266.

13 U. S. Bur. Chem. Bull. 73, p. 173.

14 J. Landw., 1900,4^:379.

EX. SACCHARINE PRODUCTS.

1 PREPARATION OF SAMPLE.— TENTATIVE.

(a) Liquids (molasses, sirups, etc.). — Mix materials of this class thoroughly.
If crystals of sugar are present, dissolve them either by heating gently or by weigh-
ing the whole mass, then adding water, heating until completely dissolved and
after cooling, re-weighing. Calculate all results to the weight of the original
substance.

(b) Semisolids (Jellies, jams, etc.). — Weigh 50 grams of the sample into a 250
cc. graduated flask. Treat with water, fill to the mark and mix thoroughly. If
insoluble material remains, mix uniformly by shaking before taking aliquots for
the various determinations.

(C) Solids (sugar, confectionery, etc.). — Grind and mix thoroughly materials
of this class to secure uniform samples.

Moisture.

DRYING METHODS.

2 SUGARS.— OFFICIAL.

Dry 2-5 grams in a flat dish (nickel, platinum, or aluminium) at the temperature
of boiling water for 10 hours; cool in a desiccator and weigh; then dry again for an
hour or until there is only a slight change in weight.

With some sugars, more especially those of large grain, there is danger of occlu-
sion and retention of water. The International Commission for Unifying Methods
of Sugar Analysis prescribe drying at 105°-110°C. for normal beet sugars. This
temperature is sufficient to expel the last traces of occluded water and is not attended
with sufficient decomposition to affect the weight of the product. The drying tem-
perature should never exceed 110°C1.

MASSECUITES, MOLASSES, AND OTHER LIQUID AND SEMILIQUID PRODUCTS.

3 Drying upon Pumice Stone. — Tentative.

Prepare pumice stone of two grades of fineness, one of which will pass through
a 1 mm. sieve, the other through a 6 mm. sieve. Make the determination in flat
metallic dishes or in shallow, flat-bottomed, weighing bottles. Place a layer of
the fine pumice stone, 3 mm. in thickness, on the bottom of the dish, then a layer
of the coarse pumice stone 6-10 mm. in thickness, dry and weigh. Dilute the sam-
ple with a weighed portion of water so that the diluted material shall contain 20-
30% of solid matter. Weigh into the dish, prepared as described above, an amount
of the diluted sample to yield, approximately, 1 gram of dry matter. If this weigh-
ing can not be made rapidly, use a weighing bottle provided with a cork through
which a pipette passes. Dry in vacuo at 70°C. to constant weight, making trial
weighings at intervals of 2 hours. For substances containing little or no levulose
or other readily decomposable substance, the drying may be made in a water oven
at the temperature of boiling water.

4 Drying upon Quartz Sand. — Tentative.

Digest pure quartz sand with strong hydrochloric acid, wash, dry, and ignite.
Preserve in a stoppered bottle.

121

122 METHODS OF ANALYSIS [Chap.

Place 6-7 grams of the prepared sand and a short stirring rod in a flat-bottomed
dish. Dry thoroughly, cool in a desiccator, and weigh. Then add 3-4 grams of
the molasses, mix with the sand (if necessary to thoroughly incorporate the two,
add a little water), dry in a water oven at the temperature of boiling water
for 8-10 hours, stirring at intervals of an hour, cool in a desiccator, and weigh.
Stir, heat again for an hour, cool, and weigh. Repeat the heating and weighing
until the loss of water in an hour is not greater than 3 mg.

AREOMETRIC METHODS.

(Not applicable to low-grade sugar products, molasses and other materials
containing large amounts of non-sugar solids.)

SPECIFIC GRAVITY, WATER AND TOTAL SOLIDS.
5 By Means of a Spindle.— Official.

The density of juices, sirups, etc., is most conveniently determined by means
of the Brix hydrometer. For rough work, or where less accuracy is desired, the
Baume" hydrometer may be used. The Brix spindle should be graduated to tenths.
The range of degrees recorded by each individual spindle should be as limited as
possible. The solution should be as nearly as practicable of the same tempera-
ture as the air at the time of reading, and, if the variation from the temperature
of the graduation of the spindle amounts to more than 1°, a correction must be
applied according to the table under 6. Before taking the density of a juice, allow
it to stand in the cylinder until all air bubbles have escaped, and until all fatty or
waxy matter has come to the surface and been skimmed off. The cylinder should

be large enough in diameter to allow the hydrometer to come to rest without touch-

20 °C
ing the sides. A table of specific gravities at — p-1 and per cent by weight of suc-
rose is given under 9, and a table for the comparison of specific gravities at 17 .. ',
degrees Brix (per cent by weight of sucrose), and degree Baume is given under 8.

If the sample is too dense to determine the density directly, dilute a weighed
portion with a weighed quantity of water, or dissolve a weighed portion and dilute
to a known volume with water.

In the first instance the per cent of total solids is calculated by the following

formula:

WS
Per cent of solids in the undiluted material = — in which

w

S = per cent of solids in the diluted material;

W = weight of the diluted material;

w = weight of the sample taken for dilution.

When the dilution is made to a definite volume, the following formula is to be
used:

Per cent of solids in the undiluted material = / in which

V = volume of the diluted solution at a given temperature;
D = specific gravity of the diluted solution at the same temperature;
S = per cent of solids in the diluted solution at the same temperature;
W = weight of the sample taken for dilution at the same temperature.

If the spindle reading be made at any other temperature than 17.5°C., the re-
sult should be corrected according to the following:

IX]

SACCHARINE PRODUCTS

123

Table 9.

For correction of the readings of the Brix spindle when made at other than the
standard temperature, 17.5°C.

(For temperatures below 17.5°C. the correction is to be subtrac

ted.)

TEM-

DEGREE

BRIX OF THE SOLUTION

PERA-

TURE

0

5

10

15

20

25

30

35

40

50

60

70

75

°C.

0

0.17

0.30

0.41

0.52

0.62

0.72

0 82

0.92

0.98

1.11

1 22

1.25

1 29

5

0.23

0 30

0.37

0.44

0.52

0.59

0.65

0.72

0.75

0.80

0 88

0.91

0 94

10

0.20

0.26

0.29

0.33

0.36

0.39

0.42

0.45

0.48

0.50

0 54

0.58

0.61

11

0.18

0.23

0.26

0.28

0.31

0.34

0.36

0.39

0.41

0 43

0 47

0.50

0 53

12

0.16

0.20

0.22

0.24

0.26

0.29

0.31

0.33

0.34

0.36

0.40

0.42

0.46

13

0.14

0.18

0.19

0.21

0.22

0.24

0.26

0.27

0.28

0 29

0.33

0.35

0.39

14

0.12

0 15

0.16

0.17

0.18

0.19

0.21

0.22

0.22

0.23

0.26

0.28

0.32

15

0.09

0.11

0.12

0 14

0.14

0.15

0.16

0.17

0.16

0 17

0.19

0.21

0.25

16

0.06

0.07

0.08

0 09

0.10

0 10

0.11

0.12

0.12

0.12

0 14

0 16

0.18

17

0.02

0.02

0.03

0.03

0.03

0.04

0.04

0.04

0.01

0.04

0.05

0.05

0.06

18

0.02

0.03

0.03

0.03

0.03

0.03

0 03

0 03

0.03

0 03

0.03

0.03

0.02

19

0.06

0.08

0.08

0.09

0.09

0.10

0.10

0.10

0.10

0 10

0.10

0.08

0.06

20

0.11

0.14

0.15

0.17

0.17

0.18

0.18

0.18

0 19

0 19

0.18

0.15

0.11

21

0.16

0.20

0.22

0.24

0.24

0.25

0.25

0.25

0.26

0 26

0.25

0.22

0.18

22

0.21

0.26

0.29

0.31

0.31

0 32

0.32

0.32

0.33

0.34

0.32

0.29

0.25

23

0.27

0.32

0 35

0 37

0.38

0.39

0.39

0 39

0.40

0.42

0.39

0.36

0.33

24

0 32

0 38

0.41

0.43

0.44

0.46

0.46

0 47

0.47

0.50

0.46

0.43

0 40

25

0.37

0.44

0.47

0 49

0.51

0.53

0.54

0 55

0.55

0 58

0.54

0.51

0.48

26

0.43

0.50

0.54

0.56

0.58

0.60

0.61

0.62

0 62

0.66

0.62

0.58

0.55

27

0.49

0.57

0.61

0.63

0.65

0.68

0.68

0.69

0 70

0.74

0.70

0 65

0.62

28

0.56

0.64

0.68

0.70

0.72

0.76

0.76

0.78

0.78

0 82

0.78

0.72

0.70

29

0.63

0 71

0.75

0.78

0.79

0.84

0.84

0.86

0.86

0.90

0.86

0.80

0.78

30

0.70

0.78

0.82

0.87

0.87

0.92

0.92

0.94

0.94

0.98

0.94

0.88

0.86

35

1.10

1.17

1.22

1.24

1.30

1.32

1.33

1.35

1.36

1.39

1.31

1.27

1.25

40

1.50

1 61

1.67

1.71

1.73

1 79

1.79

1.80

1.82

1.83

1.78

1.69

1 65

50

2.65

2.71

2.74

2.78

2.80

2.80

2.80

2.80

2.79

2.70

2.56

2.51

60

3.87

3.88

3.88

3.88

3.88

3.88

3.88

3.90

3.82

3.70

3.43

3.41

70

5.17

5.18

5.20

5.14

5.13

5.10

5.08

5.06

4.90

4.72

4.47

4.35

80

6.62

6.59

6.54

6.46

6.38

6.30

6.26

6.06

5 82

5.50

5.33

90

8.26

8.16

8.06

7.97

7.83

7.71

7.58

7.30

6.96

6.58

6.37

100

10.01

9.87

9.72

9.56

9.39

9.21

9.03

8.64

8.22

7.76

7.42

Example. — A sugar solution shows a reading of 30.2° Brix at 30°C. To find the
necessary correction for the conversion of this reading to the reading which would
have been obtained if the observation had been made at 17.5°C, find the vertical
column in the table headed 30° Brix, which is the nearest to the observed reading.
Follow down this column until the number is reached which is opposite to the tem-
perature of observation — in this case 30°. The number found, 0.92, is to be added
to the observed reading.

By Means of a Pycnometer. — Official.

20 "C.

(a) By specific gravity at —^-i' — Determine the specific gravity of the solution

20°C
at -p-' by means of a pycnometer and ascertain the corresponding per cent by

weight of sucrose from 9. When the density of the substance is too high for a direct
determination, dilute and calculate the sucrose content of the original material as
directed under 5.

(b) By specific gravity at 17 5. ' • — Proceed as directed under (a), the determina-

1 7 ico 9n°r^

tions of specific gravity being made at 17 5„ ' instead of at -jr^' Ascertain the corre-
sponding per cent by weight of sucrose from 8.

The pycnometer determination should not be made at any other temperature

., 17.5°(''. 20°C.

than 175. or -js—

124

METHODS OF ANALYSIS

[Chap.

8

Table 10.

17. 5° C.
17.5°

Degree Baume = 146.78

For the comparison of specific gravities at * 0', degrees Brix and degrees Baume' .

146.78
sp.gr.

DEGBEE

DEGREE

DEGREE

BBIX OB

BRIX OR

BRIX OR

PEB CENT

SPECIFIC

DEGREE

PER CENT

SPECIFIC

DEGREE

PER CENT

8PECIFTC

DEGREE

BT
WEIGHT

GBAVITY

baum£ 1

BY

WEIGHT

GRAVITY

BAUME

WEIGHT

GRAVITY

BACME

OF

OF

OF

8UCB0BE

8UCRO8E

SUCROSE

1.0

1.00388

0.6

33.0

1 . 14423

18.5

65.0

1.31989

35.6

2.0

1.00779

1.1

34.0

1.14915

19.05

66.0

1.32601

36.1

3.0

1.01173

1.7

35.0

1.15411

19.6

67.0

1.33217

36.6

4.0

1.01570

2.3 j

36.0

1.15911

20.1

68.0

1.33836

37.1

5.0

1.01970

2.8

37.0

1 . 16413

20.7

69.0

1.34460

37.6

6.0

1.02373

3.4

38.0

1 . 16920

21.2

70.0

1.35088

38.1

7.0

1.02779

4.0 !

39.0

1 . 17430

21.8

71.0

1.35720

38.6

8.0

1.03187

4.5

40.0

1 . 17943

22.3

72.0

1.36355

39.1

9.0

1.03599

5.1

41.0

1 . 18460

22.9

73.0

1.36995

39.6

10.0

1.04014

5.7

42.0

1 . 18981

23.4

74.0

1.37639

40.1

11.0

1.04431

6.2

43.0

1 . 19505

23.95

75.0

1.38287

40.6

12.0

1.04852

6.8

44.0

1.20033

24.5

76.0

1.38939

41.1

13.0

1.05276

7.4 1

45.0

1.20565

25.0

77.0

1.39595

41.6

14.0

1.05703

7.9

46.0

1.21100

25.6

78.0

1.40254

42.1

15.0

1.06133

8.5 !

47.0

1.21639

26.1

79.0

1.40918

42.6

16.0

1.06566

9.0

48.0

1.22182

26.6

80.0

1.41586

43.1

17.0

1.07002

9.6 i

49.0

1.22728

27.2

81.0

1.42258

43.6

18.0

1.07441

10.1

50.0

1.23278

27.7

82.0

1.42934

-14.1

19.0

1.07884

10.7

51.0

1.23832

28.2

83.0

1.43614

44.6

20.0

1.08329

11.3

52.0

1.24390

28.8

84.0

1.44298

45.1

21.0

1.08778

11.8

53.0

1.24951

29.3

85.0

1.44986

45.5

22.0

1.09231

12.4

54.0

1.25517

29.8

86.0

1.45678

46.0

23.0

1.09686

13.0

55.0

1.26086

30.4

87.0

1.46374

46.5

24.0

1.10145

13.5

56.0

1.26658

30.9

88.0

1.47074

47.0

25.0

1 . 10607

14.1

57.0

1.27235

31.4

89.0

1.47778

47.45

26.0

1.11072

14.6

58.0

1.27816

31.9

90.0

1.48486

47.9

27.0

1.11541

15.2

59.0

1.28400

32.5

91.0

1.49199

48.5

28.0

1.12013

15.7

60.0

1.28989

33.0

92.0

1.49915

48.9

29.0

1.12488

16.3

61.0

1.29581

33.5

93.0

1.50635

49.4

30.0

1 . 12967

16.8

62.0

1.30177

34.0

94.0

1.51359

49.8

31.0

1 . 13449

17.4

63.0

1.30777

34.5

95.0

1.520S7

50.3

32.0

1 . 13934

17.95

64.0

1.31381

35.1

When the number expressing the specific gravity found by analysis falls between
the numbers given in the above table, the exact equivalent in degrees Brix or Baume
is found by a simple calculation.

Example. — The pycnometer shows the specific gravity of a certain sirup to be
1.20909. The table shows that the corresponding degree Brix is between 45.0 and
46.0. Subtracting the specific gravity of a solution of 45° Brix from the correspond-
ing figure for 46°, we have (expressing the specific gravities as whole numbers)
121,100 — 120,565 = 535, the difference in specific gravity for 1° Brix at this point
in the table. Subtracting the specific gravity corresponding to 45° from the spe-

344
cific gravity found by analysis, we have 120,909 - 120,565 = 344;^ = 0.64, the frac-
tion of 1° Brix more than 45°. The degree Brix, corresponding to a sp. gr. of 1.20909,
is therefore 45.64.

IX]
9

saccharine products

Table 11.
Densities2 of solutions of cane sugar at

125

°C.

(This table is the basis for standardizing hydrometers indicating per cent of suear

at 20°C.)

PER CENT
SUGAR

10
11

12
13
14

15
16

17
18
19

20
21

22
23
24

25
26
27
28
29

30
31
32
33
34

35
36
37
38
39

40
41
42
43
44

45
46
47
48
49

50
51
52
53
54

55
56
57
58
59

TENTHS OF PER CENT

0.998234
1.002120
1.006015
1.009934
1.013881

1.017854
1.021855
1.025885
1.029942
1.034029

1.038143
1.042288
1.046462
1.050665
1.054900

1.059165
1.063460
1.067789
1.072147
1.076537

1.080959
1.085414
1.089900
1.094420
1.098971

1.103557
1.108175
1.11282S
1.117512
1.122231

1.126984
1.131773
1.136596
1.141453
1 . 146345

0.998622
1.002509
1.006 105
1.010327
1.014277

1.018253
1.022257
1.026289
1.030349
1.034439

1.038556
1.042704
1.046881
1.051087
1.055325

1.059593
1.063892
1.068223
1.072585
1.076978

1.081403
1.085861
1.090351
1.094874
1.099428

1.104017
1.108639
1.113295
1.117982
1.122705

1.127461
1.132254
1.137080
1.141941
1 . 146836

1.151275 1.151770
1.156238 1.156736

1.161236
1.166269
1.171340

1.176447
1.181592
1.186773
1.191993
1.197247

1.202540
1.207870
1.213238
1.218643
1.224086

1.229567
1.235085
1.240641
1.246234
1.251866

1.257535
1.263243

1.268989
1.274774
1.280595

1.161738
1.166775
1.171849

1.176960
1.182108
1.187293
1.192517
1.197775

1.203071
1.208405
1.213777
1.219185
1.224632

1.230117
1.235639
1.241198
1.246795
1.252431

1.258104
1.263816
1.269565
1.275354
1.281179

0.999010
1.002897
1.006796
1.010721
1.014673

1.018652
1.022659
1.026694
1.030757
1.034850

1.038970
1.043121
1.047300
1.051510
1.055751

1.060022
1.064324
1.068658
1.073023
1.077419

1.081848
1.086309
1.090802
1.095328
1.099S86

1.104478
1.109103
1.113763
1.118453
1.123179

1.127939
1.132735
1.137565
1 . 142429
1 . 147328

1.152265
1.157235
1.162240
1.167281
1.172359

1 . 177473
1.182625
1.187814
1.193041
1 . 198303

1.203603
1.20.S940
1.214317
1.219729
1.225180

1.23066S
1.236194
1.241757
1.247358
1.252997

1.258674
1.264390
1.270143
L.275936
1.281764

0.999398
1.003286
1.007188
1.011115
1.015070

1.019052
1.023061
1.027099
1.031165
1.035260

1.039383
1.043537
1.047720
1.051933
1.056176

1.060451
1.064756
1.069093
1.073461
1.077860

1.082292
1.086757
1.091253
1.095782
1 . 100344

1.104938
1 . 109568
1.114229
1.118923
1.123653

1.128417
1.133216
1 . 138049
1.142916
1 . 147820

1.152760
1.157733
1.162742
1.167786
1.172869

1.177987
1.183142
1 . 1 .ss:;:;.-,
1.193565
1 . 198832

1.204136

1.209477
1.214856
1.220272
1.225727

1.231219
1.236748
1.242315
1.247920
1.253563

1.259211
1.264963
1.270720
1.276517

0.999786
1.003675
1.007580
1.011510
1.015467

1.019451
1.023463
1.027504
1.031573
1.035671

1.039797
1.043954
1.048140
1.052356
1.056602

1.060880
1.065188
1.069529
1.073900
1.078302

1.082737
1.087205
1.091704
1.096236
1 . 100802

1 . 105400
1.110033
1.114697
1.119395
1.124128

1.128896
1.133698
1.138534
1 . 143405
1.148313

1.153256
1.158233
1.163245
1.168293
1.173379

1.178501
1 . 183660
1.188856
1.191090
1.199360

1.204668

1.210013
1.215395
1.220815
1.226274

1.231770
1.237303
1.242873
1.248482
L. 254129

1.271299
1 277098
l 28293S

1.000174
1.004064
1.007972
1.011904
1.015864

1.019851
1.023867
1.027910
1.031982
1.036082

1.040212
1.044370
1.048559
1.052778
1.057029

1.061308
1.065621
1.069964
1.074338
1.078744

1.083182
1.087652
1.092155
1.096691
1.101259

1.105862
1.110497
1.115166
1.119867
1 . 124603

1.129374
1.1341
1 . 139020
1 . 143894
1 . 148805

1 . 153752
1 . 158733
1.163748

1 . 168800
1 . 173889

1.179014
1.184178
1 . 189379
1.194616
1 . 199890

1.205200
L. 210549

1.215936
1.221360
1.226823

1.232322
1.237859
1.243433

1.254697

1.260385
1.266112
1.271877
1.277680
1.283521

1.000563
1.004453
1.008363
1.012298
1.016261

1.020251
1.024270
1.028316
1.032391
1.036494

1.040626
1.044788
1.048980
1.053202
1.057455

1.061738
1.066054
1.070400
1.074777
1.079187

1.083628
1.088101
1.092607
1.097147
1.101718

1 . 106324
1.110963
1.115635
1.120339
1.125079

1.129853
1 . 134663
1.139506
1.144384
1 . 149298

1 . 154249
1.159233
1.164252
1.169307
1.174400

1.179527
1.184696

1.1 vim 1 1
1.195141
1.200420

1.205733
1.211086
1.216476
1.221904
1.227371

1.232874
1.238414
L.243992

1.249609

1.278262
1 284107

1.000952
1.004844
1 .008755
1.012694
1.016659

1.020651
1.024673
1.028722
1.032800
1.036906

1.041041
1.045206
1.049401
1.053626
1.057882

1.062168
1.066487
1.070836
1.075217
1.079629

1.084074
1.088550
1.093060
1.097603
1.102177

1.106786
1.111429
1.116104
1.120812
1 . 125555

1.130332
1.135146
1.139993
1.144874
1 . 149792

1.164746

1.159733
1.164756
1.169815
1.174911

1.180044
1.185215
1.190423
1 . 195667
1.200950

1.206266

1.217017
1 22 1449
1.227919

1.244652

1.250172
1.255831

1.261527

1 278844
1.284694

1.001342
1.005234
1.009148
1.013089
1.017058

1.021053
1.025077
1.029128
1.033209
1.037318

1.041456
1.045625
1.049822
1.054050
1.058310

1.062598
1.066921
1.071273
1.075657
1.080072

1.084520
1.089000
1.093513
1.098058
1.102637

1 . 107248
1.111895
1.116572

1.121284
1.126030

1.130812
1 . 135628
1.140479
1.145363
1.150286

1.155242
1.160233
1.165259

1.176423

1.180560
1.185734
1.190946
1 .196193
1.201480

L. 206801
1.212162

1.217559
1.222995
1.228469

1.239527
1.245113

i

1.27.(1111
1.279428

1.001731
1.005624
1.009541
1.013485
1.017456

1.021454
1.025481
1.029535
1.033619
1.037730

1.041872
1.046043
1.050243
1.054475
1.058737

1.063029
1.067355
1.071710
1.076097
1.080515

1.084967
1.089450
1.093966
1.098514
1.103097

1.107711
1.112361
1 .117042

1.121757
1.126507

1.131292
1.136112
1 . 140966

1 . 145854
1.150780

1.155740
1.160734
1.165764
1.170831
1.175935

1.181076
1.186253
1.191469
1.196720
1.202010

1.207335
1.212700
1 218101
1.223540

1.229018

1 234632

1 . 256967

1.268413

1.274194

1 286869

126
9

METHODS OF ANALYSIS

Table 11. — Continued.

Densities of solutions of cane sugar at 20°C.

[Chap.

TENTHS OP

PER CENT

PER CENT

SU^AB

0

1

2

3

4

5

6

7

8

9

60

1.286456

1.287044

1.287633

1.288222

1.288811

1.289401

1.289991

1.290581

1.291172

1.291763

61

1.292354

1.292946

1.293539

1.294131

1.294725

1.295318

1.295911

1.296506

1.297100

1.297696

62

1.298291

1.298886

1.299483

1.300079

1.300677

1.301274

1.301871

1.302470

1.303068

1.303668

63

1.304267

1.304867

1.305467

1.306068

1.306669

1.307271

1.307872

1.308475

1.309077

1.309680

64

1.310282

1.310885

1.311489

1.312093

1.312699

1.313304

1.313909

1.314515

1.315121

1.315728

65

1.316334

1.316941

1.317549

1.318157

1.318766

1.319374

1.319983

1.320593

1.321203

1.321814

66

1.322425

1.323036

1.323648

1.324259

1.324872

1.325484

1.326097

1.326711

1.327325

1.327940

67

1.328554

1.329170

1.329785

1.330401

1.331017

1.331033

1.332250

1.332868

1.333485

1.334103

68

1.334722

1.335342

1.335961

1.336581

1.337200

1.337821

1.338441

1.339063

1.339684

1.340306

69

1.340928

1.341551

1.342174

1.342798

1.343421

1.344046

1.344671

1.345296

1.345922

1.346547

70

1.347174

1.347801

1.348427

1.349055

1.349682

1.350311

1.350939

1.351568

1.352197

1.352827

71

1.353456

1.354087

1.354717

1.355349

1.355980

1.356612

1.357245

1.357877

1.358511

1.359144

72

1.359778

1.360413

1.361047

1.361682

1.362317

1.362953

1.363590

1.364226

1.364864

1.365501

73

1.366139

1.366777

1.367415

1.368054

1.368693

1.369333

1.369973

1.370613

1.371254

1.371894

74

1.372536

1.373178

1.373820

1.374463

1.375105

1.375749

1 .376392

1.377036

1.377680

1.378326

75

1.378971

1.379617

1.380262

1.380909

1.381555

1.382203

1.382851

1.383499

1.384148

1.384796

76

1.385446

1.386096

1.386745

1.387396

1.388045

1.388696

1.389347

1.389999

1.390651

1 391303

77

1.391956

1.392610

1.393263

1.393917

1.394571

1.395226

1.395881

1.396536

1.397192

1.397848

78

1.398505

1.399162

1.399819

1.400477

1.401134

1.401793

1.402452

1.403111

1.403771

1.404430

79

1.405091

1.405752

1.406412

1.407074

1.407735

1.408398

1.409061

1.409723

1.410387

1.411051

80

1.411715

1.4123S0

1.413044

1.413709

1.414374

1.415040

1.415706

1.416373

1.417039

1.417707

81

1.418374

1.419043

1.419711

1.420380

1.421049

1.421719

1.422390

1.423059

1.423730

1.424400

82

1.425072

1.425744

1.426416

1.427089

1.427761

1.428435

1.429109

1.429782

1.430457

1.431131

83

1.431807

1.432483

1.433158

1.433835

1.434511

1.435188

1.435866

1.436543

1.437222

1.437900

84

1.438579

1.439259

1.439938

1.440619

1.441299

1.441980

1.442661

1.443342

1.444024

1.444705

85

1 .445388

1.446071

1.446754

1.447438

1.448121

1.448806

1.449491

1.450175

1.450860

1.451545

86

1.452232

1.452919

1.453605

1.454292

1.454980

1.455668

1.456357

1.457045

1.457735

1.458424

87

1.459114

1.459805

1.460495

1.461186

1.461877

1.462568

1 .463260

1.463953

1.464645

1.465338

88

1.466032

1.466726

1.467420

1.468115

1.468810

1.469504

1 470200

1.470896

1.471592

1.472289

89

1.472986

1.473684

1.474381

1.475080

1.475779

1.476477

1.477176

1.477876

1.478575

1.479275

90

1.479976

1.480677

1.481378

1.482080

1.482782

1.483484

1.484187

1.484890

1.485593

1.486297

91

1.487002

1.4S7707

1.488411

1.489117

1.489823

1.490528

1.491234

1.491941

1.492647

1.493355

92

1.494063

1 .494771

1.495479

1.496188

1.496897

1.497606

1.498316

1.499026

1.499736

1.500447

93

1.501158

1.501870

1.502582

1.503293

1.504006

1.504719

1.505432

1.506146

1.506859

1.507574

94

1.508289

1.509004

1.509720

1.510435

1.511151

1.51186S

1.512585

1.513302

1.514019

1.514737

95

1.515455

1.516174

1.516893

1.517612

1.518332

1.519051

1.519771

1.520492

1.521212

1.521934

96

1.522656

1.523378

1.524100

1.524823

1.525546

1.526269

1.526993

1.527717

1.528441

1.529166

97

1.529891

1.530616

1.531342

1.532068

1.532794

1.533521

1.53424S

1.534976

1.535704

1.536432

98

1.537161

1.537889

1.538618

1.539347

1.540076

1.540806

1.541536

1.542267

1.542998

1.543730

99

1.544462

1.545194

1.545926

1.543659

1.547392

1.548127

1.548861

1.549595

1.550329

1.551064

100

1.551800

10

REFRACTOMETER METHOD.— TENT A TIVE.

Determine the refractive index of the solution at 28°C. and obtain the corre-
sponding percentage of dry substance from 11. If the refractive index is obtained
at a temperature other than 28°C, correct the result as indicated in 12. If the
solution is too dark to be read in the instrument, dilute with a concentrated sugar
solution. Water should never be used for this purpose. Mix weighed amounts
of the solution under examination and a solution of pure sugar of about the same
strength, and obtain the amount of dry substance in the former by the following
formula:

IX]

SACCHARINE PRODUCTS

127

(A + B) C - BD
A

in which

x = per cent of dry substance to be found;

A = weight in grams of the material mixed with B;

B = weight in grams of pure sugar solution employed in the dilution;

C = per cent of dry substance in the mixture of A and B obtained from the

refractive index;
D = per cent of dry substance in the pure sugar solution obtained from its
refractive index.

11 Table 12.— Geerligs'3 Table.

For dry substance in sugar-house -products by the Abbe refractometer, at 28°C.

INDEX

PER

CENT
DRY
SUB-
STANCE

DECIMALS TO BE
ADDED FOR
FRACTIONAL
READINGS*

INDEX

PER

CENT
DRY
SUB-
STANCE

DECIMALS TO BE
ADDED FOR
FRACTIONAL
READINGS*

INDEX

PER
CENT
DRY
SUB-
STANCE

DECIMALS TO BE
ADDED FOR
FRACTIONAL
READINGS1

1.3335
1.3349
1.3364
1.3379
1.3394
1.3409
1.3424
1.3439
1.3454
1.3469

1

2
3
4
5
6
7
8
9
10

0.0001 =0.05

0 0002 = 0 1
0 0003 = 0 2
0 0001 = 0.25
0.0005 = 0.3
0 0006 = 0.4
0.0007 = 0.5
0 0003 = 0 6
0 0009 = 0.7
0.0010 = 0.75
0 0011 = 0.8
0 0012 =08
0 0013 = 0.85
0.0014 = 0.9
00015= 1.0

1.3484
1.3500
1.3516
1.3530
1.3546
1.3562
1.3578
1.3594
1.3611
1.3627
1.3644
1.3661
1.3678
1.3695
1.3712
1.3729

11

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

0 0001 = 0.05

0 0002 = 0 1
0 0003 = 0.2
0 0004 = 0.25
0.0005 = 0.3
0 0006 = 0.4
0.0007 = 0.45
0.000S = 0.5
0.0009 = 0.6
0 0010 = 0.65
0 0011 = 0.7
0.0012 = 0.75
0 0013 = 0.8
0.0014 = 0.85
0 0015 = 09
0.0016= 0.95

1.3746
1.3764
1.3782
1.3800
1.3818
1.3836
1.3854
1.3872
1.3890
1.3909
1.3928
1.3947
1.3966
1.3984
1.4003

27
28
29
30
31
32
33
34
35
36
37
38
39
40
41

0.0001 = 0.05
0 0002 = 0 1
0 0003 = 0.15
0 0004 = 0.2
0.0005 = 0 25
0 0006 = 0.3
0 0007 = 0. 35
0.0008= 0.4
0.0009 = 0.45
0.0010= 0.5
0 0011 = 0 55
0 0012 = 0 6
0 0013 = 0.65
0 0014 = 0 7
0 1015 = 0.75
0.(016 = 0.8
0 0017 = 0 85
0.0018 = 0 9
0 0019 = 0 95
0 0020= 1 0
00u21= 1.0

1.4023
1.4043
1.4063
1.4083
1.4104
1.4124
1.4145
1.4166
1.4186
1.4207
1.4228
1.4249
1.4270

42
43
44
45
46
47
48
49
50
51
52
53
54

1

0 001 = 0.05
0 0002 = 0.1
0.0003 = 0.15
0.0004= 0.2
0 0005 = 0 25
0 0006 = 0.3
0.0007 = 035
0.0003 = 0 4
0.0009 = 0 45
0 0010 = 0 5
0 0011 = 0 55
0 0012 = 0.6
0.0013 = 0 65
0 0014 = 0 7
0 0015 = 0 75
0 0016 = 0.8
0.0017 = 0 85
0 0018 = 0 9
0 0019 = 0.95
0 0020 = 1 0
0.0021 = 1.0

1.4292
1.4314
1.4337
1.4359
1.4382
1.4405
1.4428
1.4451
1.4474
1.4497
1.4520
1.4543
1.4567
1.4591
1.4615
1.4639
1.4663
1.4687

55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72

0.0001 = 0.05
0 0002 = 0 1
0 0003 = 01
0 0004 = 0 15
0.0005 = 0 2
0.0006 = 0 25
0.0007 = 0 3
0.0008 = 0 35
0.0009 = 0 4
0 0010 = 0.45
0 0011 =05
0 0012 = 0 5
0.0013 = 0 55
0 0014 = 06
0.0015 = 0 65
0 0016 = 07
0 0017 = 0 75
0.0018 = 0.8
0 0019 = 0 85
0 0020 = 09
0.0021 = 0 9
0.0022 = 0.95
0 0023 =10
0.0024= 1.0

1.4711
1.4736
1.4761
1.4786
1.4811
1.4836
1.4862
1.4888
1.4914
1.4940
1.4966
1.4992
1.5019
1.5046
1.5073
1.5100
1.5127
1.5155

73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90

0 0001 = 0 0
0 0002 = 0 05
0.0003 = 0 1
0 0004 = 0.15
0 0005 = 0.2
0 0006= 0 2
0.0007 = 0 25
0 0008 =03
0 0009 = 0.35
0 0010 = 0 35
0 0011 = 04
0 0012 = 0 45
0 0013 = 05
0 0014 = 0 5
0 0015 = 0 55
0 0016 = 0 6
0 0017 = 0 65
0 0018 = 0 65
0 0019 = 07
0 0020 = 0 75
0 0021 =08
= (18
= 0.85
0 0024 = 09
= 09
0 0026

ii 0027 - 1 o
■ =10

*Find in the table the refractive index which is next lower than the reading actu-
ally made and note the corresponding whole number for t he per rent of dry substance
Subtract the refractive index obtained from the table From the observed reading;
the decimal corresponding to this difference, as given in the column so marked, is

added to the whole per cent of dry substance as first obtained.

128
12

methods of analysis

Table 13.
Corrections for temperature.

[Chap,

DRY SUBSTANCE

TURE OF

THE

0

5

10

15

20

25

30

40

50

60

70

80

90

PRISMS IN

°C.

Subtract

20

0.53

0.54

0.55

0.56

0.57

0.58

0.60

0.62

0.64

0.62

0.61

0.60

0.58

21

0.46

0.47

0.48

0.49

0.50

0.51

0.52

0.54

0.56

0.54

0.53

0.52

0.50

22

0.40

0.41

0.42

0.42

0.43

0.44

0.45

0.47

0.48

0.47

0.46

0.45

0.44

23

0.33

0.33

0.34

0.35

0.36

0.37

0.38

0.39

0.40

0.39

0.38

0.38

0.38

24

0.26

0.26

0.27

0.28

0.28

0.29

0.30

0.31

0.32

0.31

0.31

0.30

0.30

25

0.20

0.20

0.21

0.21

0.22

0.22

0.23

0.23

0.24

0.23

0.23

0.23

0.22

26

0.12

0.12

0.13

0.14

0.14

0.15

0.15

0.16

0.16

0.16

0.15

0.15

0.14

27

0.07

0.07

0.07

0.07

0.07

0.07

0.08

0.08

0.08

0.08

0.08

0.08

0.07

Add—

29

0.07

0.07

0.07

0.07

0.07

0.07

0.08

0.08

0.08

0.08

0.08

0.08

0.07

30

0.12

0.12

0.13

0.14

0.14

0.14

0.15

0.15

0.16

0.16

0.16

0.15

0.14

31

0.20

0.20

0.21

0.21

0.22

0.22

0.23

0.23

0.24

0.23

0.23

0.23

0.22

32

0.26

0.26

0.27

0.28

0.28

0.29

0.30

0.31

0.32

0.31

0.31

0.30

0.30

33

0.33

0.33

0.34

0.35

0.36

0.37

0.38

0.39

0.40

0.39

0.38

0.38

0.38

34

0.40

0.41

0.42

0.42

0.43

0.44

0.45

0.47

0.48

0.47

0.46

0.45

0.44

35

0.46

0.47

0.48

0.49

0.50

0.51

0.52

0.54

0.56

0.54

0.53

0.52

0.50

13

ASH.

Method I. — Official.

Heat 5-10 grams of the sample in a 50-100 cc. platinum dish at 100°C. until the
water is expelled, add a few drops of pure olive oil, and heat slowly over a flame
until swelling ceases. Then place the dish in a muffle and heat at low redness until
a white ash is obtained.

14

Method II. — Official.

Carbonize the mass at a low heat, dissolve the soluble salts in hot water, burn
the residual mass as directed in 13, add the solution of soluble salts, and evaporate
to dryness at 100°C, ignite gently, cool in a desiccator, and weigh.

15

Method III— Official.

Saturate the sample with sulphuric acid, dry, ignite gently, then burn in a muf-
fle at low redness. Deduct one tenth of the weight of the ash, and calculate the
per cent.

16 QUANTITATIVE ANALYSIS OF THE ASH.— OFFICIAL.
Proceed as directed under III.

17 SOLUBLE AND INSOLUBLE ASH.-TENTATIVE.

Ash the material as directed under 13 or 14. Add water to the ash in the plati-
num dish, heat nearly to boiling, filter through an ashless filter paper, and wash
with hot water until the combined filtrate and washings measure about 60 cc. Re

IX] SACCHARINE PRODUCTS 129

turn the filter paper and contents to the platinum dish, ignite carefully, and weigh.
Calculate the percentages of water-soluble and water-insoluble ash.

1 8 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE.

Cool the filtrate from 1 7 and titrate with N/10 hydrochloric acid, using methyl
orange as an indicator.

Express the alkalinity in terms of the number of cc. of N/10 acid per 1 gram of
the sample.

1 9 ALKALINITY OF THE INSOLUBLE ASH.— TENTATIVE.

Add an excess of N/10 hydrochloric acid (usually 10-15 cc.) to the ignited insolu-
ble ash in the platinum dish, under 17, heat to boiling over an asbestos plate, cool,
and titrate the excess of hydrochloric acid with N/10 sodium hydroxid, using methyl
orange as an indicator.

Express the alkalinity in terms of the number of cc. of N/10 acid per 1 gram of
the sample.

20 MINERAL ADULTERANTS IN THE ASH.— TENTATIVE.

Mix 100 grams of molasses, sirup, honey, or the confectionery solution prepared
as directed under 1 (b) and evaporate to a sirupy consistency, with about 35 grams
of concentrated sulphuric acid in a large porcelain evaporating dish. Pass an
electric current through it while stirring by placing one platinum electrode. in the
bottom of the dish near one side and attaching the other to the lower end of the
glass rod with which the contents are stirred. Begin with a current of about 1
ampere and gradually increase to 4 (modified from method of Budde and Schou4
for determining nitrogen electrolytically). In 10-15 minutes the mass is reduced
to a fine dry char, which may be readily burnt to a white ash in the original dish
over a free flame or in a muffle.

This method5 is preferred to the ordinary method of heating with sulphuric acid,
especially in the case of molasses, because, if properly manipulated, it comes quietly
into the form of a very finely divided char or powder, especially adapted for subse-
quent quick ignition.

If an electric current is not available, treat in a large porcelain dish 100 grams of
the saccharine solution, evaporated to a sirupy consistency, with sufficient concen-
trated sulphuric acid to thoroughly carbonize the mass and ignite in the usual
manner.

The following adulterants may be present: salts of tin, used in molasses to bleach;
mineral pigments, such as chromate of lead in yellow confectionery; oxid of iron,
sometimes used to simulate the color of chocolate; and copper. These elements
may be detected by the usual qualitative tests.

21 NITROGEN.— TENTATIVE.

Determine nitrogen in 5 grams of the material as directed under I, 1 8, 21 or 23,
using a larger quantity of the sulphuric acid if necessary for complete digestion.

SUCROSE.

22 Method I. — Tentative.

(Substances in which the volume of the combined insoluble matter and precipitate
from clarifying agents is less than 1 cc. from 26 grams.)

Determine sucrose by polarization before and after inversion, as directed under

VIII, 14.

130 METHODS OF ANALYSIS [Chap.

All products which contain dextrose or other reducing sugars in the crystalline
form, or in supersaturated solution, exhibit the phenomenon of birotation. The con-
stant rotation only should be employed in the Clerget formula, and to obtain this
the solutions prepared for direct polarization should be allowed to stand overnight
before making the reading. If it is desired to make the direct reading immediately,
the birotation may be destroyed by heating the neutral solution to boiling for a few
minutes or by adding a few drops of strong ammonium hydroxid before completing
the volume.

23 Method II. (Double dilution method.6) — Tentative.

(Substances in which the volume of the combined insoluble matter and
precipitate from clarifying agents is more than 1 cc. from 26 grams.)

Weigh out a half normal weight of the sample and make up the solution to 100
cc, employing the appropriate clarifier (basic lead acetate for dark colored con-
fectionery or molasses and alumina cream for light colored confectionery). Also
weigh out a normal weight of the sample and make up a second solution with the
clarifier to 100 cc. Filter and obtain direct polariscopic readings of both solu-
tions. Invert each solution as directed in 22 and obtain its invert reading.

The true direct polarization of the sample is the product of the two direct read-
ings divided by their difference.

The true invert polarization is the product of the two invert readings divided
by their difference.

Calculate the sucrose from the true polarizations thus obtained by the formula
given under VIII, 14.

COMMERCIAL GLUCOSE (APPROXIMATE).

24 Method I. — Tentative.

(Substances containing little or no invert sugar.)

Commercial glucose can not be determined accurately owing to the varying
amounts of dextrin, maltose, and dextrose present in this product. However, in
sirups, in which the amount of invert sugar is so small as not to appreciably affect
the result, commercial glucose may be estimated approximately by the following
formula:7

(a - S) 100 .

G = in which

175

G = per cent of commercial glucose;

a = direct polarization;

S = per cent of cane sugar.

Express the results in terms of commercial glucose polarizing + 175°V.

Method II. — Tentative.

23 (Substances containing invert sugar.7)

Prepare an inverted half normal solution of the substance as directed under
VIII, 14 except that after inversion cool the solution, make neutral to phenol-
phthalein with sodium hydroxid solution, slightly acidify with hydrochloric acid,
and treat with 5-10 cc. of alumina cream before making up to the mark. Filter
and polarize at 87°C. in a 200 mm. jacketed tube. Multiply the reading by 200 and
divide by the factor 163 to express the amount of glucose present in terms of glu-
cose polarizing +175°V.

IX] SACCHARINE PRODUCTS 131

26 REDUCING SUGARS.— TENTATIVE.

Determine either as dextrose or invert sugar as directed under VIII, 50, 51 ,

52, 54, or 21, 23, 25, 36 or 39.

27 STARCH.— TENTATIVE.

Measure 25 cc. of a solution or uniform mixture, prepared as directed in 1 (b),
(representing 5 grams of the sample) into a 300 cc. beaker, or introduce 5 grams of
the finely ground sample (previously extracted with ether if the sample contains
much fat) into the beaker, add sufficient water to make the volume 100 cc, heat
to about 60°C. (avoiding if possible gelatinizing the starch) and allow to stand
for about an hour, stirring frequently to secure complete solution of the sugars.
Transfer to a stout wide-mouthed bottle, rinse the beaker with a little warm water,
cool, add an equal volume of 95% alcohol, mix, and allow to stand at least an hour.
Centrifugalize until the precipitate is closely packed on the bottom of the bottle
and decant the supernatant liquid through a hardened filter. Wash the precipi-
tate with successive 50 cc. portions of 50% alcohol by centrifugalizing and decant-
ing through the filter until 3 or 4 drops of the washings give no test for sugar with
alphanaphthol as described under 68. Transfer the residue from the bottle and
the hardened filter to a large flask and determine starch as directed under VIII,

60.

ETHER EXTRACT IN CONFECTIONERY.

28 Continuous Extraction. — Tentative.

(1) Measure 25 cc. of a 20% mixture or solution, prepared as directed under 1
(b), into a very thin, readily frangible, glass evaporating shell (Hofmeister Schalchen),
containing 5-7 grams of freshly ignited asbestos fiber; or (2) If impossible to ob-
tain a uniform sample, weigh 5 grams of the mixed finely divided sample into a
dish, and wash with water upon the asbestos in the evaporating shell, using, if neces-
sary, a small portion of the asbestos fiber on a stirring rod to transfer the last traces
of the sample from the dish to the shell. Dry to constant weight at 100°C, cool,
wrap loosely in smooth paper, crush into rather small fragments between the fin-
gers, transfer carefully the crushed mass, exclusive of the paper, to an extraction
tube or a fat extraction cartridge. A thin lead disk (bottle cap) may be substituted
for the Schalchen. The disk may then be cut into small pieces and placed in the
extraction tube. Extract with anhydrous ether or petroleum ether (I), p. 45°-60°C.
and without weighable residue) in a continuous extraction apparatus for at least 25
hours. In most cases it is advisable to remove the substance from the extractor
after the first 12 hours, grind with sand to a fine powder, and re-extract for the re-
maining 13 hours. Transfer the extract to a tared flask, evaporate the solvent, dry
to constant weight in an oven at 100°C.

29 Roese-Gottlieb Method. — Tentative.

Substances such as butter-scotch, invariably yield extremely inaccurate results
by the above method. In such cases introduce 1 grams of the material, or an amount
of a uniform solution equivalent to this amount of the dry substance, into a Rohrig
tube or similar apparatus, make up to a volume of 10 cc. with water, add 1.25 cc.
of concentrated ammonium hydroxid and mix thoroughly. Add 10 ee. of 95' , alco-
hol and mix. Then add 25 cc. of washed ether and shake vigorously for half a min-
ute; then add 25 cc. of petroleum ether (!>. p. below ml shake again for
half a minute. Allow to stand for 20 minutes or until the separation between the

132 METHODS OF ANALYSIS [Chap.

liquids is complete. Draw off as much as possible of the ether-fat solution (usually
0.5-0.8 cc. will be left) into a weighed flask through a small, rapid filter. The flask
should be weighed with a similar one as a counterpoise. Again extract the liquid
remaining in the tube, this time with 15 cc. each of ether and petroleum ether, shake
vigorously half a minute with each, and allow to settle. Proceed as above, wash-
ing the tip of the spigot and the filter with a few cc. of a mixture of equal parts of
the 2 ethers (previously mixed and free from deposited water). For absolutely
exact results the extraction must be repeated. This third extraction usually yields
not more than about 1 mg. of fat, if the previous ether-fat solutions have been
drawn off closely, or an amount averaging about 0.02% on a 4 gram charge. Evapo-
rate the ether slowly on a steam bath, then dry the fat in a boiling water oven until
the loss in weight ceases. Test the purity of the fat by dissolving in a little petro-
leum ether. Should a residue remain, wash the fat out completely with petroleum
ether, dry the residue, weigh, and deduct the weight.

30 PARAFFIN IN CONFECTIONERY.— TENTATIVE.

Add to the ether extract in the flask, as above obtained, 10 cc. of 95% alcohol
and 2 cc. of sodium hydroxid solution (1 to 1), connect the flask with a reflux con-
denser, and heat for an hour on the water bath, or until saponification is complete.
Remove the condenser and allow the flask to remain on the bath until the alcohol
is evaporated and the residue is dry. Dissolve the residue as completely as pos-
sible in about 40 cc. of water and heat on the bath, shaking frequently. Wash into
a separatory funnel, cool, and extract with 4 successive portions of petroleum ether,
which are collected in a tared flask or capsule. Evaporate the petroleum ether
and dry in the oven to constant weight.

Any phytosterol or cholesterol present in the fat would be extracted with the
paraffin. The amount is so insignificant that it may be disregarded generally.
The character of the final residue should, however, be confirmed by determining
its melting point, specific gravity, and refractive index.

31 ALCOHOL IN SIRUPS USED IN CONFECTIONERY ("BRANDY DROPS")-— TENTATIVE.

Collect in a beaker the sirup from a sufficient number of pieces to yield 30-50
grams of sirup. Strain the sirup into a tared beaker and weigh. Introduce the
sirup into a 250-300 cc. distilling flask, dilute with half its volume of water, attach
the flask to a vertical condenser and distil almost 50 cc, or as much of the liquid as
possible without causing charring. Foaming may be prevented by adding a little
tannin, or a piece of paraffin about the size of a pea, to the contents of the distil-
lation flask. Cool the distillate, make up to volume with water, mix well, and
ascertain the specific gravity of the liquid by means of a pycnometer, and obtain
the corresponding weight of alcohol in the 50 cc. of distillate from XVI, 5. Cal-
culate the per cent by weight of alcohol in the candy filling.

32 COLORING MATTER.— TENTATIVE.
Proceed as directed under XI.

33 METALS.— TENTATIVE.
Proceed as directed under XII.

IX] SACCHARINE PRODUCTS 133

HONEY.8

34 PREPARATION OF SAMPLE.— TENTATIVE.

(a) Liquid or strained honey. — If the sample is free from granulation, mix thor-
oughly by stirring or shaking before drawing weighed portions for the analytical
determination. If the honey is granulated, place the container, having the stopper
loose, in a water bath, and heat at a temperature not exceeding 50°C. until the sugar
crystals dissolve; mix thoroughly, cool, and weigh portions for the analytical de-
terminations. If sediment such as particles of comb, wax, sticks, bees, etc., are
present, heat the sample to 40°C. in a water bath and filter through cheese-cloth
before weighing portions for analysis.

(b) Comb honey. — Cut across the top of the comb, if sealed, and separate com-
pletely from the comb by straining through a 40 mesh sieve. When portions of the
comb or wax pass through the sieve, heat the sample as in (a) and strain through
cloth. If the honey is granulated in the comb, heat until the wax is liquified, stir,
cool, remove the wax and take the clear liquid for analysis.

35 MOISTURE.

Weigh 2 grams of the sample into a tared, flat-bottomed aluminium dish, having a
diameter of about 60 mm. and containing 10-15 grams of fine quartz sand, which has
been previously washed, dried and ignited, and a small glass stirring rod; add 5-10
cc. of water and thoroughly incorporate with the sand and honey mixture by means
of the rod; dry the dish and its contents to constant weight in a vacuum oven at
a temperature not exceeding 70°C.

36 ASH.— OFFICIAL.

Weigh 5-10 grams of honey into a platinum dish, add a few drops of pure olive
oil to prevent spattering, and heat carefully until swelling ceases and then ignite
at a temperature not above dull redness until a white ash is obtained.

37 SOLUBLE ASH.— TENTATIVE.

Proceed as directed under 17.

38 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE;.

Proceed as directed under 18.

POLARIZATION.

39 Direct Polarization. — Tentative.

(a) Immediate direct polarization. — Transfer 26 grams of the honey to a 100
cc. flask with water, add 5 cc. of alumina cream, dilute to the mark with water at
20°C, filter, and polarize immediately in a 200 mm. tube.

(b) Constant direct polarization. — Pour the solution from the tube used in read-
ing (a) back into the flask, stopper, and allow to stand for 24 hours. At the end of
this time again polarize the solution at 20°C. in a 200 mm. tube.

(C) Birotation. — The difference between (a) and (b) gives the birotation.
(d) Direct polarization at 87°C. — Polarize the solution, obtained in (b), at 87°C.
in a jacketed 200 mm. tube.

134 METHODS OF ANALYSIS [Chap.

40 Invert Polarization. — Tentative.

(a) At 20°C. — Invert 50 cc. of the solution obtained in 39 as directed under
VIII, 14 or 16, and polarize at 20°C. in a 200 mm. tube.

(b) At 87°C. — Polarize the solution, obtained as directed in (a), at 87°C. in a 200
mm. jacketed tube.

41 REDUCING SUGARS.— TENTATIVE.

Dilute 10 cc. of the solution, used for direct polarization, 39, to 250 cc. and de-
termine reducing sugars in 25 cc. of this solution by one of the methods given under
VIII, 25, 36, 39 or 56, respectively. Calculate the result to per cent of invert
sugar.

42 SUCROSE.— TENTATIVE.

Proceed as directed under VIII, 18. Determine reducing sugars after inver-
sion by diluting 10 cc. of the solution obtained in 40, with a small amount of water,
neutralizing with sodium carbonate, and making up to 250 cc. with water. Employ
50 cc. of this solution for the determination, using the same method as in 41.

43 LEVULOSE.— TENTATIVE.

Multiply the direct reading at 87°C, 39 (d), by 1.0315 and subtract the product
from the constant direct polarization at 20°C, 39 (b); divide the difference by 2.3919
to obtain the grams of levulose in a normal weight of the honey. From this figure
calculate the per cent of levulose in the original sample.

44 DEXTROSE.— TENTATIVE.

Subtract the per cent of levulose, obtained in 43, from the per cent of invert
sugar, found in 41, to obtain the approximate per cent of dextrose.

The dextrose can be determined more accurately by multiplying the per cent
of levulose, as found in 43, by the factor 0.915, which gives its dextrose equivalent
in copper reducing power. Subtract this figure from that of the reducing sugars. 41 ,
calculated as dextrose, to obtain the percentage of dextrose in the sample. (Owing
to the difference in the reducing powers of different sugars, the sum of the dex-
trose thus found and the levulose as obtained in 43 will be greater than the amount
of invert sugar obtained in 41).

45 DEXTRIN (APPROXIMATE).— TENTATIVE.

Transfer 8 grams of the sample (4 grams in the case of dark colored honey-dew
honey) to a 100 cc. flask (using not more than 4 cc. of water) by allowing the sam-
ple to drain from the weighing dish into the flask and then dissolving the residue in
2 cc. of water. After adding this solution to the contents of the flask, rinse the
weighing dish with two 1 cc. portions of water to which a little alcohol is added sub-
sequently. Fill the flask to the mark with absolute alcohol, shaking constantly.
Set the flask aside until the dextrin has collected on the sides and bottom and the
liquid is clear. Decant the clear liquid through a filter paper and wash the resi-
due in the flask with 10 cc. of 95% alcohol, pouring the washings through the same
filter. Dissolve the dextrin in the flask with boiling water and filter through the
filter paper already used, receiving the filtrate in a tared dish, prepared as directed
under 4. Rinse the flask and wash the filter a number of times with small portions
of hot water, evaporate on a water bath and dry to constant weight in vacuo
at 70°C.

IXJ SACCHARINE PRODUCTS 135

After determining the weight of the alcohol precipitate, dissolve the latter in
water and make up to definite volume, using 50 cc. of water for each 0.5 gram of pre-
cipitate or part thereof.

Determine reducing sugars in the solution both before and after inversion as
directed under VIII, 18, expressing the results as invert sugar. Calculate sucrose
from the results thus obtained and subtract the sum of the reducing sugars before
inversion and sucrose from the weight of the total alcoholic precipitate to obtain
the weight of the dextrin.

46 FREE ACID.— TENTATIVE.

Dissolve 10 grams of the honey in water and titrate with N/10 sodium hydroxid
using phenolphthalein as an indicator. Express the results in terms of cc.of N/10
sodium hydroxid required to neutralize 100 grams of the sample.

47 GLUCOSE.— TENTATIVE.

Qualitative test.'— Dilute the honey with water in the proportion of 1 to 1, then add
a tew cc. of iodin solution (1 gram of iodin, 3 grams of potassium iodid, 50 cc. of
water). In the presence of glucose the solution turns red or violet, the depth and
character of the color depending upon the quality and nature of the glucose em-
ployed. A blank test with a pure honey of about the same color should be made
in order to secure an accurate color comparison. Should the honey be dark and
the percentage of glucose very small, precipitate the dextrin which may be pres-
ent by adding several volumes of 95% alcohol. Allow to stand until the precipitate
settles (do not filter), decant the liquid, dissolve the residue of dextrins in hot
water, cool and apply the above test to this solution. A negative result is not
proof of the absence of glucose as some glucose, especially of high conversion, does
not give any reaction with iodin.9

Quantitative test. — An approximate determination can be made by Browne's
formula as follows: Multiply the difference in the polarizations of the invert solu-
tion at 20°C. and 87°C. by 77 and divide this product by the percentage of invert
sugar after inversion found in the sample. Multiply the quotient by 100 and di-
vide the product by 26.7, to obtain the percentage of honey in the sample; 100 per
cent minus the per cent of honey gives the percentage of glucose.

COMMERCIAL INVERT SUGAR."

QUALITATIVE TESTS.
Fiehe Test (Bryan Modification"). — Tentative.

48 REAGENT.

Resorcin solution. — Dissolve 1 gram of resorcin in 100 cc. of hydrochloric acid,
Bp. gr. 1.19.

49 MANIPULATION".

Introduce 10 cc. of a 50% honey solution into a test tube and add 5 cc. of ether.
Shake gently and allow to stand for some time until the ether layer is clear. Trans-
fer 2 cc. of this clear ether solution to a small test tube and add a large drop of the
resorcin solution. Shake and note the color immediately. In the presence of arti-
ficial invert sugar, the resorcin assumes immediately an orange-red color turning
to dark red.

136 METHODS OF ANALYSIS [Chap.

Feder Anilin Chlorid Test.12 — Tentative.

50 REAGENT.

Anilin chlorid solution. — To 100 cc. of C. P. anilin add 30 cc. of 25% hydrochloric
acid.

51 MANIPULATION.

Introduce 5 grams of the honey into a porcelain dish and add 2.5 cc. of the anilin
reagent. A bright red color indicates the presence of commercial invert sugar.

52 DIASTASE."

Mix 1 part of honey with 2 parts of sterile water. Treat 10 cc. of this solution
with 1 cc. of 1% soluble starch solution and digest at 45°C. for an hour. At the end
of this time test the mixture with 1 cc. of iodin solution (1 gram of iodin, 2 grams
of potassium iodid, 300 cc. of water). Treat another 10 cc. portion of the honey
solution, mixed with 1 cc. of the soluble starch solution, without heating to 45°C,
with the reagent and compare the colors produced. If the original honey had not
been heated sufficiently to kill the diastase, an olive-green or brown coloration will
be produced in the mixture that has been heated at 45°C. Heated or artificial
honey becomes blue.

MAPLE PRODUCTS.

53 PREPARATION OF SAMPLE.— TENTATIVE.

(a) Maple sirup. — Determine the moisture by the method given under 54 (a). If
the moisture is less than 35%, and there is some mineral sediment, pour the clear
sirup into a beaker, washing the sediment also into the beaker with water. Then
concentrate the sirup by boiling to a moisture content of about 35% (b. p. 104°C).
Set aside until cool, or preferably let the covered material stand overnight, and
pour off the clear liquid for the analytical work. Where no sediment is present
the sample is ready for analysis after careful mixing. Where sugar has crystal-
lized out, warm to dissolve the sugar before starting the analysis. It is desira-
ble in order to compare results upon different samples, to reduce all results other
than moisture to a dry substance basis as determined in the clear sirup.

(b) Maple sugar, maple cream, maple wax, etc. — Determine moisture, by the meth-
od given under 54 (b), in the sample in its original condition by thoroughly mixing,
if semi-plastic, or by rubbing up in a mortar representative portions of the product
if solid. For all other analytical determinations use a solution prepared as fol-
lows: Weigh roughly 100 grams of the product into a beaker and dissolve by boil-
ing with 200 cc. of water. Decant the resulting sirup while hot through a muslin
filter, concentrate by boiling to a moisture content of 35% (b. p. 104°C), cool, or
preferably let the covered material stand overnight, set aside until clear, and use
this clear sirup for analysis. It is desirable, in order to compare results upon
different samples, that all results except moisture be expressed upon a dry basis.

54 MOISTURE.— TENTATIVE.

(a) Maple sirup. — Proceed as directed under 35 or 10.

(b) Maple sugar, maple cream, etc. — Proceed as directed under 35.

55 POLARIZATION.— TENTATIVE.

(a) Direct at 20°C— Proceed as directed under VIII, 14.

(b) Invert at 20°C— Proceed as directed under VIII, 14.

(C) Invert at 87°C. — Proceed as directed under 25 to detect commercial glucose.

IX] SACCHARINE PRODUCTS 137

56 REDUCING SUGARS AS INVERT SUGAR.— TENTATIVE.

(a) Before inversion. — Proceed as directed under VIII, 25, using an aliquot of
the solution used for direct polarization, 55 (a), and only neutral lead acetate for
clarification.

(b) After inversion. — Proceed as directed under VIII, 25, using an aliquot of
the solution used for the invert polarization, 55 (b), and only neutral lead acetate
for clarification.

SUCROSE.

57 By Polarization. — Tentative.
Proceed as directed under VIII, 14 or 16.

58 By Reducing Sugars Before and After Inversion. — Tentative.
Proceed as directed under VIII, 18.

59 TOTAL ASH.— TENTATIVE.

Proceed as directed under 13.

60 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE.

Proceed as directed under 17.

61 ALKALINITY OF THE SOLUBLE ASH— TENTATIVE.
Proceed as directed under 18.

62 ALKALINITY OF THE INSOLUBLE ASH.— TENTATIVE.
Proceed as directed under 19.

LEAD NUMBER (WINTON).— TENTATIVE.

63 REAGENTS.

Standard basic lead acetate solution. — Boil 430 grams of normal lead acetate and
130 grams of litharge, for 30 minutes, or boil 560 grams of Home's dry basic lead
acetate with 1 liter of water, cool, allow to settle and dilute the supernatant liquid
to 1.25 sp. gr. To a measured amount of this solution add 4 volumes of water and
filter if not perfectly clear. The solution should be standardized each time a set
of determinations is made.

If the directions for preparing the basic lead acetate are not carried out care-
fully, the use of Home's dry basic lead acetate is preferable.

64 DETERMINATION OF LEAD IN THE BLANK.

Transfer 25 cc. of the standard basic lead acetate to a 100 cc. flask, add a few drops
of acetic acid, and make up to the mark with water. Shake and determine lead
sulphate in 10 cc. of the solution as directed under 65. The use of the acid is im-
perative in this case to keep the lead in solution, when diluted with water.

65 DETERMINATION.

Transfer 25 grams of the sample to a 100 cc. flask by means of water. Add 25
cc. of the standard basic lead acetate and shake, fill to the mark, shake, and allow to
stand for at least 3 hours before filtering. Pipette 10 cc. of the clear filtrate into
a 250 cc. beaker, add 40 cc. of water and 1 cc. of concentrated sulphuric acid, shake
and add 100 cc. of 95% alcohol. Allow to stand overnight, filter on a tared Gooch,

138 METHODS OF ANALYSIS [Chap.

wash with 95% alcohol, dry in a water oven, and ignite in a muffle or over a Bun-
sen burner, applying the heat gradually at first, and avoiding a reducing flame.
Cool and weigh. Subtract the weight of lead sulphate so found from the weight of
lead sulphate found in the blank, 64, and multiply by the factor 27.325. The use
of this factor gives the lead number directly without the various calculations other-
wise required.

MALIC-ACID VALUE.

66 Cowles Method.™ — Tentative.

Weigh 6.7, grams of the sample into a 200 cc. beaker, add 5 cc. of water, then 2
cc. of a 10% calcium acetate solution and stir. Add gradually, and with constant
stirring, 100 cc. of 95% alcohol, and agitate the solution until the precipitate set-
tles, or let stand, until the supernatant liquid is clear. Filter off the precipitate
and wash with 75 cc. of 85% alcohol. Dry the filter paper and ignite in a platinum
dish. Add 10 cc. of N/10 hydrochloric acid and warm gently until all the lime
dissolves. Cool and titrate back with N/10 sodium hydroxid, using methyl orange
as an indicator. The difference in cc. divided by 10 represents the malic acid value
of the sample. Previous to use the reagents should be tested by a blank determina-
tion and any necessary corrections applied.

67 METALS.— TENTATIVE.
Proceed as directed under XII.

SUGAR HOUSE PRODUCTS.

SUCROSE IN BEETS.

68 Alcohol Extraction Method (Herzfeld Modification16). — Tentative.

Weigh 26 grams of the beet pulp and transfer to a 100 cc. flask with about 50 cc.
of 90% alcohol and 3-5 cc. of basic lead acetate solution. Connect a reflux condenser
to the flask and place on a boiling water bath for 10-15 minutes. Then pour the
whole into a Soxhlet extractor, washing out the flask with fresh portions of 90%
alcohol. Connect the same 100 cc. flask to the extractor, and fit the latter with
a return condenser. Add 90% alcohol until the siphon is started and the flask is
about three fourths full. Place the flask in a covered water bath kept at a heat
that will allow the alcohol to boil freely. Continue the extraction for 1-4 hours,
or until a test of the alcohol in the extractor gives no color withalpha-naphthol
solution when tested as follows: Introduce into a test tube a few drops of the alco-
hol coming from the extractor, add 4 or 5 drops of a 20% alcoholic alpha-naphthol
solution and 2 cc. of water. Shake well, tip the tube, and allow 2-5 cc. of colorless
concentrated sulphuric acid to flow down the side of the tube; then hold the tube
upright and, if sucrose is present, a color varying from a faint to a deep violet will
be noted at the junction of the two liquids. On shaking, the whole solution becomes
a blue violet color. This test is suitable for this work, but it must be remembered
that other substances besides sucrose give this color reaction.

Remove the flask, transfer to a 100 cc. graduated flask, cool to the standard
temperature, dilute to the mark with 90% alcohol, shake and filter, keeping the
funnel covered with a watch glass. Polarize in a 200 mm. tube.

Avoid evaporation and changes of temperature and also use a minimum amount
of basic acetate for clarification, 3 cc. rather than 5 cc. By digesting the beet
pulp with the alcohol before extraction, the time of extraction is greatly shortened
the pulp becomes thoroughly impegnated with the alcohol, an^l all t!ie air is re-
moved, resulting in a good extraction of the whole material. If the pulp is fine

IX] SACCHARINE PRODUCTS 139

and tends to clog the siphon, alcohol-washed cotton may be used as a plug in the
extractor before adding the beet pulp, and a fine mesh screen may be placed over
the pulp to keep the whole compact in the extractor.

69 Pellet Aqueous Method16 (Hot Digestion). — Tentative.

Weigh 52 grams of the beet cuttings and transfer them with water to a wide-
mouthed flask graduated to a content of 201.2 cc; add 5-10 cc. of basic lead acetate
solution, fill the flask to the mark with hot water, and shake. Immerse the flask
in a water bath at 80°C. and rotate at intervals. Add water from time to time so
that at the end of the heating (about 30 minutes) the water in the flask is a little
above the mark. Remove the flask from the water bath and allow it to cool to
standard temperature. Add sufficient concentrated acetic acid to make the solu-
tion very slightly acid (generally less than 0.5 cc.) and a few drops of ether to break
the foam. Make up to the mark, mix thoroughly, filter, and polarize in a 200 mm.
tube.

The fineness of the pulp governs the time of heating. Add enough water at the
start and maintain this volume during the extraction, so that not more than 5 cc. of
water will be necessary to complete the volume after cooling. The proportion of
pulp to water must not be increased beyond the prescribed amount, for when smaller
proportions of water to pulp are used and then a large quantity of water is added at
the last to make up to volume, the sugar does not become equally diffused and the
results are too low. Differences of over 1% in sugar content may be caused by lack
of care in this particular.

70 Hot Water Digestion Method. — Tentative.
(Herzfeld Modification of the Sachs Le Docte Method17.)

There are needed nickel-plated sheet iron vessels, 11 cm. high, 6 cm. body diame-
ter, and 4 cm. mouth diameter, also stoppers covered with tin foil to fit the same.

Weigh 26 grams of the beet pulp on a watch glass (small enough to go into the
neck of the beaker) and transfer to the metal beaker, add 177 cc. of dilute basic
lead acetate solution (5 parts of basic lead acetate solution (sp. gr. 1.25) to 100
parts of water), shake and stopper lightly. Submerge the beaker in a water bath
at 75°-80°C. for 30 minutes, shaking intermittently. When all the air has been
expelled (generally after 5 minutes), tighten the stopper. After 30 minutes, shake,
cool to standard temperature, filter, add a drop of acetic acid to the filtrate and
polarize in a 400 mm. tube. The reading is the per cent of sugar in the beet pulp.

BIBLIOGRAPHY.

1 Browne. Handbook of Sugar Analysis. 1912, p. 16.

2 Wiss. Abh. der Kaiserlichen Normal-Eichungs-Kommission, 1900, 2: 153; U. S.
Bur. Standards, Circ. 19, 5th ed., p. 26.

3 Intern. Sugar J., 10: 69; U. S. Bur. Chem. Bull. 122, p. 169.

4 Z. anal. Chem., 1899, 38: 345.

5 Leach. Food Inspection and Analysis. 1913, p. 624.

6 Analyst, 1896, 21: 182.

7 Leach. JFood Inspection and Analysis. 1913, p. 622.

8U. S. Bur. Chem. Bulls. 110 and L54; Z. Xahr. Genussm., 1909, 18: 625.
9 U. S. Bur. Chem. Bull. 110, p. 60.

10 Ibid., 110 and 154.

11 Ibid., 154, p. 15.

12 Analyst, 1911, 36: 586.

13 Z. Nahr. Genussm., 1910, 19: 72.

14 J. Am. Chem. Soc, 190S, 30: L285

15 U. S. Bur. Chem. Bull. 140, p. 17.

16 Ibid., p. 18.

17 Ibid., p. 19.

X. FOOD PRESERVATIVES.— TENTATIVE.

SALICYLIC ACID.

1 PREPARATION OF SAMPLE.

(a) Non-alcoholic liquids. — Many liquids may be extracted directly as described
in 2 or 4 without further treatment. If gums or mucilaginous substances are present,
pipette 100 cc. into a 250 cc. volumetric flask, add about 5 grams of sodium chlorid,
shake until the latter is dissolved, make up to the mark with alcohol, shake vigor-
ously, allow the mixture to stand for 10 minutes with occasional shaking, filter
through a dry folded filter and treat an aliquot of the filtrate as directed under (b).

(b) Alcoholic liquids. — Make 200 cc. of the sample alkaline with sodium hydroxid
solution, using litmus as an indicator, and evaporate on a steam bath to about one
third its original volume. Dilute to the original volume with water and filter, if
necessary, through a dry filter.

(C) Solid or semi-solid substances. — Grind the sample and mix thoroughly. Trans-
fer a convenient quantity (50-200 grams according to the consistency of the sam-
ple) to a 500 cc. volumetric flask, add sufficient water to make a volume of about
400 cc, shake until the mixture becomes uniform, add 2-5 grams of calcium chlorid,
shake until the latter is dissolved, render distinctly alkaline with sodium hydroxid
solution, using litmus as an indicator, fill to the mark with water, shake thoroughly,
allow to stand for at least 2 hours shaking frequently and filter through a large
folded filter.

DETECTION AND ESTIMATION.

2 Ferric Chlorid Test. — Qualitative.

Introduce 50 cc. of the sample or an equivalent amount of an aqueous extract,
prepared as directed under 1, into a separatory funnel, add one tenth its volume
of dilute hydrochloric acid (1 to 3) and extract with 50 cc. of ether. If the mixture
emulsifies, add 10-15 cc. of petroleum ether (b. p. below 60°C.) and shake. If this
treatment fails to break the emulsion whirl the mixture in a centrifuge, or allow it
to stand until a considerable portion of the aqueous layer has separated, run off
the latter, shake vigorously and again allow to separate. Wash the ether layer
with two 5 cc. portions of water, evaporate the greater portion of the ether in a por-
celain dish on a steam bath, allow the remainder to evaporate spontaneously and
add a drop of 0.5% ferric chlorid solution. A violet color indicates salicylic acid.

If coloring matter or other interfering substances are present in the residue
left after evaporation of the ether, purify the salicylic acid by one of the following
methods:

(a) Dissolve the residue from the ether extract, obtained as directed above,
in about 25 cc. of ether, transfer the latter to a separatory funnel and shake with
an equal quantity of water, made distinctly alkaline with several drops of am-
monium hydroxid. Allow to separate, filter the aqueous layer through a wet fil-
ter into a porcelain dish, evaporate almost to dryness, and test the residue as diri
above.

(b) Dry the residue from the ether extract, obtained as directed above, in a
desiccator over sulphuric acid and extract with several 10 cc. portions of carbon

111

142 METHODS OF ANALYSIS [Chap.

disulphid or petroleum ether (b. p. below 60°C), rubbing the contents of the dish
with a glass rod, and filtering the successive portions of the solvent through a dry
paper into a second porcelain dish. Evaporate the greater portion of the solvent
on a steam bath, allow the remainder to evaporate spontaneously and test the
residue as directed above.

(C) Transfer the residue from the ether extract, obtained as directed above,
to a small porcelain crucible by means of a few cc. of ether and allow the solvent
to evaporate spontaneously. Cut a hole in a piece of asbestos board sufficiently
large to admit about two thirds of the crucible, cover the latter with a small, round-
bottomed flask filled with cold water, and heat over a small Bunsen flame until
any salicylic acid present has sublimed and condensed upon the bottom of the
flask. Test the sublimate as directed above.

3 Jorissen's Test.1 — Qualitative.

Dissolve the residue from the ether extract, obtained as directed under 2, or,
in case impurities are present, the purified material obtained as directed under 2
(a), (b) or (C) in a little hot water. Cool 10 cc. of the solution in a test tube, add

4 or 5 drops of 10% potassium nitrite solution, 4 or 5 drops of 50% acetic acid and
1 drop of 10% cupric sulphate solution, mix thoroughly and heat to boiling. Boil
for half a minute and allow to stand for 1-2 minutes. In the presence of salicylic
acid a blood red color will develop.

Colorimetric Method. — Quantitative.

4 EXTRACTION.

Pipette a convenient portion of the sample (100 cc. or a volume representing not
less than 20 grams of the original sample) or a solution, prepared as in 1 , into a sepa-
ratory funnel, make the solution neutral to litmus with dilute hydrochloric acid
(1 to 3) and add an excess of concentrated hydrochloric acid equivalent to 2 cc.
of acid for each 100 cc. of solution. Extract with 4 separate portions of ether,
using for each extraction a volume of ether equivalent to half the volume of the
aqueous layer. If an emulsion forms on shaking, this may usually be broken by
adding a little (one fifth the volume of the ether layer) petroleum ether (b. p. be-
low 60°C.) and shaking again or by centrifugalizing. If an emulsion still persists,
allow it to remain with the aqueous layer. If an emulsion remains after the
fourth extraction, separate it from the clear ether and the clear aqueous layer
and extract it separately with 2-3 small portions of ether. Combine the ether
extracts, wash with one tenth their volume of water, allow the layers to separate
and reject the aqueous layer. Wash in this way until the aqueous layer after sepa-
ration yields a yellow color upon the addition of methyl orange and 2 drops of X 10
sodium hydroxid. Distil slowly the greater part of the ether, transfer the remainder
to a porcelain dish and allow the ether to evaporate spontaneously. If there are
no interfering substances present, proceed as directed in 5. If such interfering
substances are present, purify the residue by one of the following methods:

(a) Dry thoroughly the residue in vacuo over sulphuric acid and extract with
10 portions of 10-15 cc. each of carbon disulphid or petroleum ether (b. p. below
60°C), rub the contents of the dish with a glass rod and filter the successive portions
of the solvent through a dry filter into a porcelain dish. Test the extracted resi-
due with a drop of ferric alum solution and, if it gives a reaction for salicylic acid,
dissolve it in water and reextract with ether, proceeding as directed above. Dis-
til the greater portion of the carbon disulphid or petroleum ether and allow the
remainder to evaporate spontaneously. Proceed as directed in 5.

X] FOOD PRESERVATIVES 143

(b) Dissolve the residue in 40-50 cc. of ether. Transfer the ether solution to
a separatory funnel and extract with 3 successive 15 cc. portions of 1% ammonium
hydroxid. (If fat is known to be present in the original ether extract, extract the
latter directly with 4 portions of the ammonium hydroxid instead of 3.) Combine
the alkaline aqueous extracts, acidify, again extract with ether and wash the com-
bined ether extracts as directed above. Distil slowly the gieater portion of the
ether, allow the remainder to evaporate spontaneously and proceed as directed in 5.

5 DETERMINATION.

Dissolve the residue, obtained in 4, in a small amount of hot water and, after
cooling, dilute to a definite volume (usually 50-100 cc), dependent on the amount
of salicylic acid present. If the solution is not clear, filter through a dry filter.
Dilute aliquots of the solution and treat with a few drops of 0.5% ferric chlorid
solution or 2% ferric alum solution.

The ferric alum solution should be boiled until a precipitate appears, allowed to
settle, and filtered. The acidity of the solution is slightly increased in this manner,
but it remains clear for a considerable time, and the turbidity caused by its dilution
with water is much less and does not appear as soon as when the unboiled solution
is used. This turbidity interferes with the exact matching of the color.

Compare the colors developed with that obtained when a standard salicylic acid
solution (containing 1 mg. of salicylic acid in 50 cc.) is similarly treated, using
Nessler tubes or a colorimeter. In either case, and especially with ferric chlorid,
avoid an excess of the reagent, although an excess of 0.5 cc. of 2% ferric alum solu-
tion may be added to 50 cc. of the comparison solution of salicylic acid without
impairing the results.

BENZOIC ACID.

PREPARATION OF SAMPLE.

6 General Method.

If solid or semi-solid, grind the sample, and mix thoroughly. Transfer about
150 grams to a 500 cc. graduated flask, add enough pulverized sodium chlorid to
saturate the water in the sample, render alkaline with sodium hydroxid solution
or milk of lime, and dilute to the mark with a saturated salt solution. Allow to
stand for at least 2 hours, with frequent shaking, and filter. If the sample contains
large amounts of matter precipitable by salt solution, it is advisable to follow a
method similar to that given under 7 (d). When alcohol is present, follow the
method given under 7 (C). When large amounts of fats are present, make an
alkaline extraction of the filtrate before proceeding as directed under 11.

7 Special Methods.

(a) Ketchup. — Saturate the water in 150 grams of ketchup by adding 15 grams of
pulverized sodium chlorid. Transfer the mixture to a 500 cc. graduated flask, rins-
ing with about 150 cc. of saturated sodium chlorid solution. Make slightly alkaline
to litmus paper with strong sodium hydroxid solution and fill to the mark with sat u-
rated salt solution. Allow to stand for at least 2 hours, shaking frequently.
Squeeze through a heavy muslin bag and then filter through a large folded filter.

(b) Jellies, jams, preserves and marmalades. — Dissolve 150 grams of the sam-
ple in about 300 cc. of saturated salt solution. Add 15 grams of pulverized sodium
chlorid. Make alkaline to litmus paper with milk of lime. Transfer to a f>00 cc.
graduated flask and dilute to the mark with saturated salt solution. Allow to

144 METHODS OF ANALYSIS [Chap.

stand for at least 2 hours, shaking frequently, centrifugalize if necessary, and
filter through a large folded filter.

(C) Cider containing alcohol, and similar products. — Make 250 cc. of the sample
alkaline to litmus paper with sodium hydroxid solution and evaporate on the steam
bath to about 100 cc. Transfer the sample to a 250 cc. graduated flask, add 30 grams
of pulverized sodium chlorid and shake until dissolved. Dilute to the original
volume, 250 cc, with saturated salt solution, allow to stand for at least 2 hours,
shaking frequently, and filter through a folded filter.

(d) Salted or dried fish. — Wash 50 grams of the ground sample into a 500 cc. gradu-
ated flask with water. Make slightly alkaline to litmus paper with strong sodium
hydroxid solution and dilute to the mark with water. Allow to stand for at least
2 hours, shaking frequently, and then filter through a folded filter. Pipette accu-
rately as large a portion of the filtrate as possible (at least 300 cc.) into a second
500 cc. flask. Add 30 grams of the pulverized sodium chlorid for each 100 cc. of
solution. Shake until the salt has dissolved and dilute to the mark with saturated
salt solution. Mix thoroughly and filter off the precipitated protein matter on
a folded filter.

8 DETECTION AND ESTIMATION.

Extract benzoic acid as directed under 2 or 4. If benzoic acid is present in
considerable quantity, it will crystallize from the ether in shining leaflets having
a characteristic odor on heating. Dissolve the residue in hot water, divide into
2 portions, and test according to 9 or 10.

9 Ferric Chlorid Test. — Qualitative.

Make the solution from 8 alkaline with ammonium hydroxid, expel the excess of
ammonia by evaporation, dissolve the residue in water, and add a few drops of a
neutral 0.5% ferric chlorid solution. A brownish precipitate of ferric benzoate
indicates the presence of benzoic acid.

10 Modified Mohler Test.2 — Qualitative.

Add to the water solution, prepared as described under 8, 1-3 cc. of N/3 sodium
hydroxid and evaporate to dryness. To the residue, add 5-10 drops of concentrated
sulphuric acid and a small crystal of potassium nitrate. Heat for 10 minutes in
a glycerol bath at 120°-130°C, or for 20 minutes in a boiling water bath. The
temperature must not exceed 130°C. After cooling add 1 cc. of water and make
distinctly ammoniacal; boil the solution to decompose any ammonium nitrite which
may have been formed. Cool and add a drop of fresh, colorless ammonium sulphid,
without allowing the layers to mix. A red-brown ring indicates benzoic acid.
On mixing, the color diffuses through the whole liquid and, on heating, finally changes
to greenish yellow. This differentiates benzoic acid from salicylic acid or cinnamic
acid. The last two form colored compounds, which are not destroyed by heating.
The presence of phenolphthalein interferes with this test.

11 Quantitative Method.

Pipette a convenient portion (100-200 cc.) of the filtrate, obtained in 6 or 7, into a
separatory funnel. Neutralize the solution to litmus paper with hydrochloric
acid (1 to 3) and add an excess of 5 cc. of the same acid. In the case of salted fish
a precipitation of protein matter usually occurs on acidifying, but the precipitate
does not interfere with the extraction. Extract carefully with chloroform, using
successive portions of 70, 50, 40, and 30 cc. To avoid an emulsion, shake cautiously

X] FOOD PRESERVATIVES 145

each time. The chloroform layer usually separates readily after standing a few
minutes. If an emulsion forms, break it: (1) by stirring the chloroform layer with
a glass rod; (2) by drawing it off into a second funnel and giving 1 or 2 sharp shakes
from one end of the funnel to the other; or (3) by centrifugalizing for a few moments.
As this is a progressive extraction, draw off carefully as much of the clear chloro-
form solution as possible after each extraction, but do not draw off any of the emul-
sion with the chloroform layer. If this precaution is taken, the chloroform extract
need not be washed.

Transfer the combined chloroform extracts to a porcelain evaporating dish,
rinse the container several times with a few cc. of chloroform, and evaporate to
dryness at room temperature in a current of air dried over calcium chlorid.

The extract may also be transferred from the separatory funnel to a 300 cc. Erlen-
meyer flask, rinsing the separatory funnel 3 times with 5-10 cc. of chloroform. Dis-
til very carefully to about one fourth the original volume, keeping the temperature
down so that the chloroform comes over in drops, not in a steady stream. Then
transfer the residue to a porcelain evaporating dish, rinsing the flask 3 times with
5-10 cc. portions of chloroform, and allow to evaporate to dryness spontaneously.

Dry the residue overnight (or until no odor of acetic acid can be detected if the
product is a ketchup) in a desiccator containing sulphuric acid. Dissolve the resi-
due of benzoic acid in 30-50 cc. of neutral alcohol, add about one fourth this volume
of water, 1 or 2 drops of phenolphthalein, and titrate with N/20 sodium hydroxid
(1 cc. is equivalent to 0.0072 gram of anhydrous sodium benzoate).

SACCHARIN.

12 Qualitative Test.

Extract with ether (after maceration and exhaustion with water, if necessary),
as directed in 1 and 4. Allow the ether extract to evaporate spontaneously and
note the taste of the residue. The presence of saccharin, to the extent of 20 mg.
per liter, is indicated by a sweet taste. Confirm by heating with sodium hydroxid,
as described below, and detecting the salicylic acid formed thereby. A sweet taste,
suggesting the presence of a trace of saccharin, has been obtained frequently in
saccharin-free wines, due to the so-called "false saccharin".

Acidify 50 cc. of a liquid food or the aqueous extract of 50 grams of a solid or semi-
solid, prepared as directed in 1 (C), and extract with ether as directed in 13. Dis-
solve the residue, remaining after evaporation of the ether, in a little hot water
and test a small portion of this solution for salicylic acid as directed under 2 or 3.
Dilute the remainder of the solution to about 10 cc, and add 2 cc. of sulphuric
acid (1 to 3). Heat to boiling and add a slight excess of 5% potassium perman-
ganate solution, drop by drop; partly cool the solution, dissolve a piece of sodium
hydroxid in it, and filter the mixture into a silver dish (silver crucible lids are well
adapted to the purpose); evaporate to dryness and heat for 20 minutes at 210°-
215°C. Dissolve the residue in water, acidify with hydrochloric acid and test the
other extract for salicylic acid as directed under 2 or 3. By this method all the
so-called "false saccharin" and the salicylic acid naturally present (also added
salicylic acid when not present in too large an amount) are destroyed, while 5 rag.
of saccharin per liter are detected with certainty.

13 Quantitative Method.

Pipette 100 cc. of the sample, or a convenient portion of a solution, prepared
as directed under 1, representing not less than 20 grams of the sample, into a sepa-

146 METHODS OF ANALYSIS [Chap.

ratory funnel, make the solution neutral to litmus with dilute hydrochloric acid
(1 to 3) and then add concentrated hydrochloric acid in the proportion of 5 cc. for
each 100 cc. of solution. Extract with 4 separate portions of ether using, for each
extraction, a volume of ether equivalent to half the volume of the aqueous layer.
If the mixture emulsifies on shaking, this difficulty may be overcome as directed
under 4. Wash the combined ether extracts with two 5 cc. portions of water, re-
move the ether by distillation, and transfer the residue into a platinum crucible
by means of a small amount of ether. Evaporate the ether on a steam bath, add
about 2-3 cc. of 10% sodium carbonate solution to the residue, rotate so that all
of the residue is brought into contact with the solution, and evaporate to dryness
on a steam bath. Add 4 grams of a mixture of equal parts of anhydrous sodium and
potassium carbonates, heat gently at first, and then to complete fusion for 30 minutes
over an alcohol or other sulphur-free flame. Cool, dissolve the melt in water, acidify
with hydrochloric acid and determine the sulphate present as barium sulphate.
Correct the result thus obtained for any sulphur present in the fusion mixture as
found in a blank determination. Calculate the amount of saccharin in the sample
by multiplying the weight of barium sulphate by 0.7845.

BORIC ACID AND BORATES.

14 Qualitative Test.'

Preliminary test. — Immerse a strip of turmeric paper in the sample acidified
with hydrochloric acid in the proportion of 7 cc. of concentrated acid to each 100
cc. of sample, and allow the paper to dry spontaneously. If borax or boric acid is
present, the paper will acquire a peculiar red color, changed by ammonium hvdroxid
to a dark blue-green but restored by acid. Solid or pasty samples may be heated
with enough water to make them sufficiently fluid, concentrated hydrochloric acid
added in about the proportion of 1 to 13 and the liquid tested in the same way.

Confirmatory test. — Make about 25 grams of the sample decidedly alkaline with
lime water and evaporate to dryness on a water bath. Ignite the residue to de-
stroy organic matter. Digest with about 15 cc. of water, add concentrated hydro-
chloric acid, drop by drop, until the ignited residue is dissolved, and then add 1 cc.
in excess. Saturate a piece of turmeric paper with the solution, and allow it to
dry without the aid of heat. In the presence of borax or boric acid, the color change
will be the same as given above.

15 Quantitative Method.4

Make 10-100 grams of the sample (depending upon the nature of the sample
and the amount of boric acid present) distinctly alkaline with sodium hvdroxid
solution and evaporate to dryness in a platinum dish. Ignite the residue until
organic matter is destroyed, avoiding an intense red heat, cool, digest with about
20 cc. of hot water, and add hydrochloric acid, drop by drop, until the reaction is
distinctly acid. Filter into a 100 cc. flask, and wash with a little hot water, the
volume of the filtrate not to exceed 50-60 cc. Return the filter containing any
unburned carbon to the platinum dish, make alkaline by wetting thoroughly with
lime water, dry on a steam bath and ignite to a white ash. Dissolve the ash in
a few cc. of dilute hydrochloric acid and add to the liquid in the 100 cc. flask, rins-
ing the dish with a few cc. of water. To the combined solutions, add 0.5 gram of
calcium chlorid and a few drops of phcnolphthalein, then 10% sodium hydroxid
solution until a permanent light pink color is produced, and finally dilute to

X] FOOD PRESERVATIVES 147

the mark with lime water. Mix and filter through a dry filter. To 50 cc. of the
filtrate add N/1 sulphuric acid until the pink color disappears, then add methyl
orange, and continue the addition of the acid until the yellow color is changed to
pink. Boil for about 1 minute to expel carbon dioxid. Cool, and carefully add
N/5 sodium hydroxid until the liquid assumes a yellow tinge, avoiding an excess
of the alkali. All the boric acid is now in a free state with no uncombined sulphuric
acid present. Add a little phenolphthalein, and an equal volume of neutral glycerol.
Titrate with N/5 sodium hydroxid until a permanent pink color is produced. About
10 grams of mannitol may be substituted for the glycerol in this determination.
At the end of the titration add an additional 2 grams and continue the titration if
the pink color is discharged. Repeat the alternate addition of mannitol and alkali
until a permanent end point is reached.

One cc. of N/5 sodium hydroxid is equivalent to 0.0124 gram of boric acid.

FORMALDEHYDE.

16 PREPARATION OF SAMPLE.

If solid or semi-solid, macerate 200-300 grams of the material with about 100 cc.
of water in a mortar. Transfer to a short-necked, 500-800 cc. copper or glass dis-
tillation flask and make distinctly acid with phosphoric acid, connect with a con-
denser and distil 40-50 cc. In the case of highly colored liquids, the same method
of preparation should be employed.

In the case of meats and fats, extract the formaldehyde with alcohol and use the
filtrate. In the case of fat, heat the mixture above the melting point of the fat to
insure thorough extraction. In the case of milk, shake with an equal volume of
strong alcohol and use the filtrate. Shake other liquids with an equal volume of
strong alcohol and filter from any insoluble matter.

QUALITATIVE TESTS.

17 Phenylhydrazin Hydrochlorid Method.*

Mix 5 cc. of the distillate, as prepared under 16, or of an alcoholic solution or
extract obtained as directed above, with 0.03 gram of phenylhydrazin hydrochlorid,
and 4 or 5 drops of a 1% ferric chlorid solution. Add slowly and with agitation,
in a bath of cold water to prevent heating the liquid, 1-2 cc. of concentrated sul-
phuric acid. Dissolve the precipitate by the addition either of concentrated sul-
phuric acid (keeping the mixture cool) or alcohol. In the presence of formaldehyde
a red color develops.

This method gives reliable reactions for formaldehyde in solutions of formalde-
hyde varying from 1 part in 50,000 to 1 part in 150,000. Acetaldehyde and benz-
aldehyde give no reaction when treated by this method and do not interfere with
the reaction given by formaldehyde.

18 Hehner Method.6

Mix about 5 cc. of the distillate, obtained in 16, with an equal volume of pure
milk, or a 1-2% solution of egg albumen, in a test tube and underlay with strong
commercial sulphuric acid without mixing. A violet or blue color at the junction
of the two liquids indicates formaldehyde. This color is given only in the presence
of a trace of ferric chlorid or other oxidizing agent. As pointed out by Hehner,
milk may be treated directly by this method and gives positive tests in the pn
of 1 or more parts of formaldehyde per 10,000. Some other articles of food rich
in proteins, for example, egg albumen, give the reaction in the presence of water
without the addition of milk.

148 METHODS OF ANALYSIS [Chap.

1 9 Leach Method.

Mix about 5 cc. of the distillate, obtained under 16, with an equal volume of pure
milk in a porcelain casserole and add about 10 cc. of concentrated hydrochloric
acid, containing 1 cc. of 10% ferric chlorid solution, to each 500 cc. of acid. Heat
to 80°-90°C. directly over the gas flame, rotating the casserole to break up the curd.
A violet coloration indicates formaldehyde.

Rimini Method.1

20 Phenylhydrazin Hydrochlorid and Sodium Nitro-prussid Test.

This method may be applied directly to liquid foods, to an aqueous or alcoholic
extract of solid foods, or to the distillate prepared as directed in 16. In the case
of milk, apply the method directly. In the case of meat, comminute the sample,
extract with 2 volumes of hot water, and employ the expressed liquid for the test.
Heat fats above their melting point with 10 cc. of alcohol, shake thoroughly, cool,
filter through a moistened filter, and use the filtrate for the test.

Dissolve a lump of phenylhydrazin hydrochlorid about the size of a pea in 3-5
cc. of the liquid to be tested, add 2-4 drops (not more) of a 5-10% sodium nitro-
prussid solution and 8-12 drops of an approximately 12% sodium hydroxid solution.
If formaldehyde is present, a green or blue color develops depending upon the
amount. When formaldehyde is present to the extent of more than 1 part in 70,000-
80,000 in the solution tested, a distinct green or bluish green reaction is obtained.
In more dilute solutions the green tint becomes less marked and a yellow tinge tend-
ing toward greenish brown develops.

With this method acetaldehyde and benzaldehyde give a color varying from
red to brown, according to the strength of the solution. A reaction may there-
fore be obtained with these aldehydes similar to that obtained with formaldehyde
in solutions more dilute than 1 part in 70,033. The presence of acetaldehyde or
benzaldehyde together with formaldehyde gives a yellowish or yellowish green
tinge. The reaction for formaldehyde may therefore be masked by the presence
of other aldehydes, but is characteristic when a clear green color is obtained.

21 Phenylhydrazin Hydrochlorid and Potassium Ferricyanid Test.

Proceed as directed in 20, substituting a solution of potassium ferricyanid for
the sodium nitro-prussid. Formaldehyde gives a red color. Alcoholic extracts
from foods must be diluted with water to prevent the precipitation of potassium
ferricyanid. The test is not applicable in the presence of the coloring matter of
blood.

22 Phenylhydrazin Hydrochlorid and Ferric Chlorid Test.

Treat 15 cc. of milk or other liquid food or of the distillate, prepared as directed
under 16, with 1 cc. of a dilute phenylhydrazin hydrochlorid solution, then with
a few drops of dilute ferric chlorid solution and, finally, with concentrated hydro-
chloric acid. The presence of formaldehyde is indicated by the formation of a
red color, which changes after some time to orange yellow.

Milk may be examined directly by this method, but more delicate tests may be
obtained from the distillate from milk or from milk serum. Acetaldehyde or benz-
aldehyde does not interfere with the reaction.

X] FOOD PRESERVATIVES 149

23 Phloroglucol Method.*

To 10 cc. of milk or other liquid food under examination in a test tube add, by
means of a pipette, 2 cc. of phloroglucol reagent (1 gram of phloroglucol, 20 grams of
sodium hydroxid and water to make 100 cc), placing the end of the pipette on the
bottom of the tube in such a manner that the reagent will form a separate layer.

If formaldehyde be present, a bright red coloration (not purple) forms at the
zone of contact. This solution gives a yellow color in the presence of some alde-
hydes, and, if it is used for the detection of aldehyde formed by the oxidation of
methyl alcohol after the destruction of ethyl aldehyde with hydrogen peroxid, an
orange yellow color will slowly appear when an insufficient amount of hydrogen
peroxid has been employed. On the other hand, if the excess of hydrogen
peroxid is not fully destroyed before the use of this reagent, a purple color develops
slowly. The clear, red color given by the use of this reagent forms quickly, and,
in the presence of but a small amount of formaldehyde fades rapidly.

FLUORIDS.

QUALITATIVE TESTS.

24 Method I.— Modified Method of Blarez.*

Thoroughly mix the sample and boil 150 cc. (in the case of solid foods an aqueous
extract may be employed provided the fluorids are in a soluble form). Add to the
boiling liquid 5 cc. of 10% potassium sulphate solution and 10 cc. of 10% barium
acetate solution. Collect the precipitate in a compact mass (a centrifuge may be
used advantageously) and wash upon a small filter. Transfer to a platinum crucible
and ignite.

Dip a carefully cleaned glass plate, while hot, in a mixture of equal parts of Car-
naiiba wax and paraffin and allow to cool. Make, with a sharp instrument, a dis-
tinctive mark through the wax, taking care not to scratch the surface of the glass.

Add a few drops of concentrated sulphuric acid to the residue in the crucible
and cover with the waxed plate, having the mark nearly over the center and mak-
ing sure that the edge of the crucible is in close contact with it. Keep the top sur-
face of the plate cool by means of a suitable device and heat the crucible for an hour
at as high a temperature as practicable without melting the wax (an electric stove
gives the most satisfactory form of heat).

If fluorids be present, a distinct etching will be apparent on the glass where it
was exposed.

25 Method II.

The preceding method may be varied by mixing a small amount of precipitated
silica with the precipitated barium fluorid and applying the method for the detection
of fluosilicates, under 27 or 28.

This method is of value in the case of foods whose ash contains a considerable
amount of silica. Under these circumstances, concentrated sulphuric acid liber-
ates silicon fluorid, which would escape detection under 24.

FLUOBORATES AND FLUOSILICATES.

26 PREPARATION OF SAMPLE.

Make about 200 grams of the sample alkaline with lime water, evaporate to dry-
ness, and incinerate. Extract the crude ash with water, to which sufficient acetic

150 METHODS OF ANALYSIS [Chap.

acid has been added to decompose carbonates, filter, ignite the insoluble portion,
extract with dilute acetic acid, and again filter. The insoluble portion now con-
tains calcium silicate and fluorid, while the filtrate will contain all the boric acid
present.

QUALITATIVE TESTS.

27 Method I.10

Incinerate the filter, from 26, containing the insoluble portion, mix with a little
precipitated silica, transfer to a short test tube, attached to a small U-tube contain-
ing a few drops of water and add 1-2 cc. of concentrated sulphuric acid. Keep
the test tube in a beaker of water on the steam bath for 30-40 minutes. If any
fluorin be present, the silicon fluorid generated will be decomposed by the water
in the U-tube and will form a gelatinous deposit on the walls of the tube.

Next test the filtrate as directed under 14. If both hydrofluoric and boric acids
be present, it is probable that they are combined as borofluorid. If, however,
silicon fluorid is detected and not boric acid, the operation should be repeated with-
out the introduction of the silica, in which case the formation of the silicon skeleton
is conclusive evidence of the presence of fluosilicate. In an ash containing an ap-
preciable amount of silica, sulphuric acid will liberate silicon fluorid rather than
hydrofluoric acid. The presence of a fluosilicate is indicated, therefore, and not
the presence of a fluorid.

28 Method II.

Incinerate the filter, from 26, containing the insoluble portion, in a platinum
crucible, mix with a little precipitated silica, and add 1 cc. of concentrated sul-
phuric acid. Cover the crucible with a watch glass, from the underside of which
a drop of water is suspended, and heat for an hour at 70°-80°C, keeping the watch
glass cooled. The silicon fluorid which is formed is decomposed by the water, leav-
ing a gelatinous deposit of silica and etching a ring at the periphery of the drop
of water. Test the filtrate for boric acid as directed under 14.

SULPHUROUS ACID.

29 Qualitative Test."

Add some sulphur-free zinc, and several cc. of hydrochloric acid to about 25
grams of the sample (with the addition of water, if necessary) in a 200 cc. Erlen-
meyer flask. In the presence of sulphites, hydrogen sulphid will be generated
and may be detected with lead acetate paper. Traces of metallic sulphids are
occasionally present in vegetables, and will give the same reaction as sulphites
under the conditions of the above test. Positive results obtained by this method
should be verified by the distillation method under 30.

It is always advisable to make the quantitative determination of sulphites,
owing to the danger that the test may be due to traces of sulphids. A trace is not
to be considered sufficient indication of the presence of sulphur dioxid either as a
bleaching agent or as a preservative.

TOTAL SULPHUROUS ACID.

30 Method I. — Distillation Method.

Distil 20-100 grams of the sample (adding recently boiled water if necessary)
in a current of carbon dioxid, after the addition of about 5 cc. of a 20% glacial phos-

X] FOOD PRESERVATIVES 151

phoric acid solution, until 150 cc. have passed over. Collect the distillate in about
100 cc. of nearly saturated bromin water, allowing the end of the condenser to dip
below the surface. The method and apparatus may be simplified without material
loss in accuracy by omitting the current of carbon dioxid, adding 10 cc. of phosphoric
acid instead of 5 cc, and dropping into the distillation flask, immediately before
attaching the condenser, a piece of sodium bicarbonate weighing not more than
1 gram. The carbon dioxid liberated is not sufficient to expel the air entirely from
the apparatus, but will prevent oxidation to a large extent. When the distillation
is finished, boil off the excess of bromin, dilute the solution to about 250 cc, add 5
cc of hydrochloric acid (1 to 3), heat to boiling, and precipitate the sulphuric acid
with 10% barium chlorid solution. Boil for a few minutes longer, allow to stand
overnight in a warm place, filter on a weighed Gooch, wash with hot water, ignite
at a dull red heat, and weigh as barium sulphate.

31 Method II. — Direct Titration Method.

In the examination of wine, fairly accurate results may be obtained by the fol-
lowing method:

Place 25 cc. of 5.6% potassium hydroxid solution in a 200 cc. flask. Introduce
50 cc. of the sample, mix with the potassium hydroxid solution, and allow the mix-
ture to stand for 15 minutes with occasional agitation. Add 10 cc. of sulphuric acid
(1 to 3) and a few cc. of starch solution, and titrate the mixture with N/50 iodin solu-
tion. Introduce the iodin solution as rapidly as possible and continue the addition
until the blue color persists for several minutes. One cc. of N/50 iodin is equiva-
lent to 0.00064 gram of sulphur dioxid.

DETERMINATION OF FREE SULPHUROUS ACID.

32 (Especially Adapted to Wine.)

Treat 50 cc. of the sample in a 200 cc. flask with about 5 cc. of sulphuric acid
(1 to 3) add about 0.5 gram of sodium carbonate to expel the air, and titrate the sul-
phurous acid with N/50 iodin, as directed under 31 .

BETA-NAPHTHOL.

33 Qualitative Test.

Extract 200 cc. of the sample, or of its aqueous extract, prepared as directed
under 1 (C), with 10 cc. of chloroform in a separatory funnel. To the chloroform
extract in a test tube add a few drops of alcoholic potash, and place in a boiling
water bath for 2 minutes. The presence of beta-napthol is indicated by the forma-
tion of a deep blue color, which changes to green and then to yellow.

ABRASTOL.
QUALITATIVE TESTS.

34 Sinibaldi Method.™

Make 50 cc. of the sample alkaline with a few drops of ammonium hydroxid and
extract with 10 cc. of amyl alcohol, adding ethyl alcohol if an emulsion is formed.
Decant the amyl alcohol, filter if turbid, and evaporate to dryness. Add to the
residue 2 cc. of nitric acid (1 to 1), heat on the water bath until half of (he liquid
is evaporated, and transfer to a test tube with the addition of 1 cc. of water. Add
about 0.2 gram of ferrous sulphate and an excess of ammonium hydroxid, drop by

152 METHODS OF ANALYSIS [Chap.

drop, with constant shaking. If the resultant precipitate is of a reddish color,
dissolve it in a few drops of sulphuric acid, and add ferrous sulphate and ammonium
hydroxid as before. As soon as a dark colored or greenish precipitate is obtained,
introduce 5 cc. of alcohol, dissolve the precipitate in sulphuric acid, shake well and
filter. In the absence of abrastol this method gives a colorless or light yellow liquid,
while a red color is produced in the presence of 0.01 gram of abrastol.

35 Sangle-Ferriere Method.1*

Boil 200 cc. of the sample with 8 cc. of concentrated hydrochloric acid for an
hour in a flask fitted with a reflux condenser. Abrastol is thus converted into beta-
naphthol and is detected as directed under 33.

SUCROL OR DULCIN.
QUALITATIVE TESTS.

36 M or pur go Method.1*

Evaporate about 100 cc. of the sample, or of the aqueous extract prepared as
directed under 1 (C) and neutralized with acetic acid, to a sirupy consistency after
the addition of about 5 grams of lead carbonate, and extract the residue several
times with 90% alcohol. Evaporate the alcoholic extract to dryness, extract the
residue with ether, and allow the ether to evaporate spontaneously in a porcelain
dish. Add 2 or 3 drops each of phenol and concentrated sulphuric acid and heat
for about 5 minutes on the water bath, cool, transfer to a test tube and overlay with
ammonium hydroxid or sodium hydroxid solution with the least possible mixing.
The presence of dulcin is indicated by the formation of a blue color at the zone of
contact.

37 Jorissen Method.16

Suspend the residue from the ether extract obtained as directed above in about
5 cc. of water; add 2-4 cc. of an approximately 10% solution of mercuric nitrate,
and heat for 5-10 minutes on the water bath. In the presence of sucrol a violet blue
color is formed, which is changed to a deep violet on the addition of lead peroxid.

FORMIC ACID.

Quantitative Method.16

38 REAGENTS.

(a) Sodium acetate solution. — Dissolve 50 grams of dry sodium acetate in suffi-
cient water to make 100 cc. and filter.

(b) Mercuric chlorid reagent. — Dissolve 100 grams of mercuric chlorid and 150
grams of sodium chlorid in sufficient water to make 1 liter and filter.

(C) Tartaric acid.

(d) Barium carbonate.

39

APPARATUS.

The apparatus required (Fig. 6) consists of a steam generator (S). a 300 cc. flask
(A) in which the sample is placed, a 500 cc. flask (/>'), containing a suspension of bari-
um carbonate, a spray trap (7'), a condenser, and a 1 liter graduated tlask (C).
The tip of the tube (D), leading into (B), consists of a bulb containing a number
of small holes to break the vapor into small bubbles.

X]

FOOD PRESERVATIVES

153

FIG. 6. APPARATUS FOR DETECTION" OF FORMIC ACID.

40

DETERMINATION.

For thin liquids like fruit juices, use 50 cc. For heavy liquids and semi-solids
like sirups and jams, use 50 grams diluted with 50 cc. of water. Place the sam-
ple in the flask (A), add 1 gram of tartaric acid, and connect as shown in Fig. 6,
the flask (B) having been charged previously with a suspension of 2 grams of barium
carbonate in 100 cc. of water. If much acetic acid is present, sufficient barium
carbonate must be used so that at least 1 gram remains at the end of the operation.
Heat the contents of flasks (A) and (B) to boiling and distil with steam from the
generator (S), the vapor passing first through the sample in flask (A), then through
the boiling suspension of barium carbonate in (B), after which it is condensed, and
measured in the graduated flask (C). Continue the distillation until 1 liter of dis-
tillate is collected, maintaining the volume of the liquids in the flasks (A) and (B)
as nearly constant as possible by heating with small Bunsen flames, and avoid-
ing charring of the sample in the flask (A). After 1 liter of distillate has been col-
lected, disconnect the apparatus and filter the contents of flask (B) while hot, wash-
ing the barium carbonate with a little hot water. The lilt rate and washings should
now measure about 110 cc. If not they should be boiled down to that volume,
add 10 cc. of the sodium acetate, 2 cc. of 10% hydrochloric acid, and 25 cc. of the
mercuric chlorid reagent. Mix thoroughly and immerse the container in a boil-
ing water bath or steam bath for 2 hours. Then filter on a tared Gooch, wash the
precipitate thoroughly with cold wafer and finally with a lit tie alcohol. Dry in a
boiling water oven for 30 minutes, cool, weigh, and calculate the weight of formic
acid present by multiplying the weight of the precipitate by 0.0975. If the weight
of mercurous chlorid obtained exceeds 1.5 grains, the determination must be re-
peated, using more mercuric chlorid reagent or a smaller amount of sample. A blank

154 METHODS OF ANALYSIS

test should be conducted with each new lot of reagents employed in the reduction,
using 150 cc. of water, 1 cc. of 10% barium chlorid solution, 2 cc. of 10% hydrochloric
acid, 10 cc. of the sodium acetate, and 25 cc. of the mercuric chlorid reagent, heat-
ing the mixture in a boiling water bath or steam bath for 2 hours. The weight of
mercurous chlorid obtained in this blank test must be deducted from that obtained
in the regular determination.

BIBLIOGRAPHY.

1 J. Ind. Eng. Chem., 1910, 2: 24.

2 Z. Nahr. Genussm., 1910, 19: 137; C. A., 1910, 4: 1523.

3 U. S. Div. Chem. Bull. 51, p. 113.

4 Sutton. Volumetric Analysis. 10th ed., 1911, p. 95.
6 Z. Nahr. Genussm., 1902, 5: 353.

6 Analyst, 1895, 20: 155.

7 Ann. di farmacoterapia e chim., 1898, 27: 97; Chem. Zentr., 1898, (1), 1152; 1902,
(1), 1076; J. Soc. Chem. Ind., 1898, 17: 697; Chem. Ztg., 1902, 26: 246; Abs. J. Chem.
Soc, 1902, 82: 367.

8 Service de Surveillance des Aliments en Belgique, through Bui. soc. chim. belg.,
1897-8, 11-12: 211; Abs. Analyst, 1897, 22: 282.

9 Chem. News, 1905, 91: 39; Ann. Rept. Mass. State Board of Health, 1905, p. 498
10Mon. Sci., 1895, (4), 9: 324.

11 U. S. Div. Chem. Bull. 13, (8), p. 1032.

12 Mon. Sci., 1893, (4), 7: 842.

13 Compt. rend., 1893, 117: 796.

14 Z. anal. Chem., 1896, 35: 104

15 Ibid., 628.

16 Biochem. Z., 1913, 51: 253.

XI. COLORING MATTERS IN FOODS.— TENTATIVE.

(An italicized number, following immediately the name of a dye, is the

number by which that dye is designated in "A Systematic Survey of

the Organic Colouring Matters", 1904, by Arthur Green,

based on the German of Schultz and Julius.)

1 PIGMENTS.

The insoluble pigments, ultramarine, lampblack, etc., are most commonly used
as facings and may be separated by washing the sample with water and allowing
the washings to settle. The particles of coloring matter can be identified by micro-
scopic examination and by treatment of the residue or purified coloring matter
with chemical reagents. A large proportion of the common pigments other than
lakes, such as the yellow, brown and red ochres and umbers, are derivatives of the
heavy metals and contain iron, manganese, etc. Others, such as various green and
blue compounds, including the green chlorophyll derivatives, contain copper.
These pigments may be identified by the usual tests for the respective metals. The
analytical properties of the insoluble coloring matters are described in various
standard works, some of which are listed in the bibliography, especially "Farb-
stofftabellen by Schultz1."

Soluble Coloring Matters and Their Lakes,
coal tar dyes.

2 Wool dyeing test2.

(a) Wines, fruit juices, distilled liquors, flavoring extracts, vinegars, beers, sirups,
non-alcoholic beverages and similar products. — Dilute 20-200 cc. of the sample with
1-3 volumes of water and boil or heat on the steam bath with a small piece of white
woolen cloth (nun's veiling). When the mixture contains much alcohol, heat until
most of the alcohol has been removed; in other cases, take out the wool after
5-15 minutes and rinse with water. Then treat the liquid with 3 or 4 drops of con-
centrated hydrochloric acid for each 100 cc. and warm again for 10-20 minutes with
a clean piece of wool. The basic dyes go on the fiber best from neutral or faintly
ammoniacal solutions and, if present, will appear on the first piece of wool. Acid
colors dye from neutral solutions but more readily from those containing free acid.
If the wool takes up any considerable amount of coloring matter in either case, the
presence of coal tar dyes is indicated. The lichen colors3 (Archil, Cudbear, Litmus)
go readily on wool, however, and many other natural colors, such as Turmeric, will
dye the fiber, if present in considerable amount. On the other band, a few coal
tar dyes, especially Auramine O and Naphthol Green B, are quite unstable ami, if
present in small amounts, may give no distinct dyeing. Acid dyes are much more
frequently used than basic dyes and in most cases may be removed from wool with-
out much decomposition by "stripping" the latter with dilute ammonia4. By the
action of the alkali, many natural colors are destroyed, while others remain for the
most part on the fiber. If the behavior with wool in neutral and acid solutions
indicates the presence of acid dyes, rinse the colored cloth thoroughly with water,
cover with 2% ammonium hydroxid solution in a casserole, boil for a few minutes,
remove the cloth and squeeze out the adhering liquid. Boil the ammoniacal solu-

155

15G METHODS OF ANALYSIS [Chap.

tion to remove the excess of ammonia, drop in a piece of clean, wet wool, make dis-
tinctly but not strongly acid with hydrochloric acid and boil again. If acid coal
tar dyes are present, they will usually give a fairly clean, bright dyeing on the second
piece of wool. A further purification may be carried out by repeating the stripping
and re-dyeing, though generally accompanied by corresponding loss of dye.

(b) Candies and similar colored sugar products. —Dissolve about 20 grams of the
sample in 100 cc. of water and treat the solution as directed under (a). When the
coloring matter is on the surface of the candy, pour off the solution before the color-
less inner portion has dissolved.

(C) Jams and jellies. — Boil a mixture of 10-20 grams of the sample and 100 cc.
of water with wool in neutral and also in acid solution as directed under (a). For
thick jams it is usually better, though less easy, first to extract the coloring sub-
stances by treating the product as directed under (d).

(d) Canned and preserved fruits and vegetables, sausage casings, smoked fish, coffee,
spices, etc. — Macerate 20-200 grams of the sample with 4-5 times its weight of 80%
alcohol. After standing a few hours pour off the solvent as completely as possible
and repeat the extraction, using 70% alcohol containing about 1% of ammonia.
(1) Examine separately the filtered alcoholic extracts as directed under (a); or, (2)
Boil the ammoniacal solution until practically neutral, complete the neutralization
with acetic acid, add the neutral 80% alcohol extract, continue the evaporation
until most of the alcohol is removed, and boil with wool as directed under (a).

(e) Cocoa and chocolate products. — Treat cocoa as directed under (d). The alco-
holic extract will contain a large amount of natural coloring matter and several
dyeings and strippings may be necessary to get rid of this in order to show the pres-
ence of coal tar dyes.

Chocolate may be treated similarly but the following procedure is preferable :
Wash 20-200 grams of the well divided sample with gasoline on a filter until most of
the fat has been removed; if the gasoline is colored, reserve for the examination of
oil-soluble dyes as directed under 3. Remove most of the adherent solvent from the
residue by evaporation or pressure between layers of absorbent paper and digest
with alcohol as directed under (d).

Coal tar dyes may also be detected in chocolate and cocoa products by mixing
directly with 3-4 times their weight of hot water and immediately boiling the magma
with wool, as directed under (a). Because of the presence of large amounts of fatty
and protein materials, this method is not very satisfactory.

(f) Cereal products. — Proceed as directed under (d), in most cases working with a
large amount of the sample, 200-500 grams, and a relatively smaller amount of alcohol.
Where tests are to be made only for the acid dyes, the extraction with neutral
80% alcohol may be omitted advantageously.

3 OIL-SOLUBLE DYES5.

Prepare an alcoholic solution of the oil-soluble dye by one of the following methods
which are to be applied to the oil or fat obtained by extraction with ether or gasoline
if the nature of the substance requires it :

(a) Shake the oil or melted fat with an equal volume of 90% alcohol. The alcohol
after separation will contain Aniline Yellow. Butter Yellow. Aminoazotoluene and
Auramine, if present.

(b) Saponify 20-200 grams of the oil or fat with alcoholic potash ami. after re-
moval of most of the alcohol on the steam bath, extract the soap with ether or gaso-
line. Most of the common dyes are removed by this treatment, though the digestion
with strong alkali may cause some decomposition and make the extraction rather
troublesome.

XI] COLORING MATTERS IN FOODS 157

(C) Dilute 20-200 grams of the oil or melted fat with 1-2 volumes of gasoline and
shake out successively with 2-4% potassium or sodium hydroxid solution, 12-15%
hydrochloric acid, and phosphoric-sulphuric acid mixture, prepared by mixing
85% phosphoric acid with about 10-20% by volume of concentrated sulphuric acid.

The dilute alkali extracts Sudan G and Annatto. The dilute hydrochloric acid
extracts Aniline Yellow (7), Aminoazotoluene, and Butter Yellow (16), the first 2
forming orange-red, the latter cherry-red solutions in this solvent. Benzeneazo-
beta-naphthylamin and homologues also come in this group, though they are not
extracted very readily and decompose rapidly on standing in strongly acid solution.
The phosphoric acid mixture is necessary for the extraction of Sudan I (11), Sudan
II (49), Sudan III (US), and the homologue of the last, Sudan IV. The procedure
is not very suitable in the presence of Auramine but this dye is seldom found in oils.
Neutralize the alkaline and dilute hydrochloric acid solutions; dilute the phosphoric
acid mixture and partially neutralize, cooling the liquid during this operation;
and extract the dyes by shaking with ether or gasoline.

For the direct dyeing test use the alcoholic solution, obtained as directed in (a).
Evaporate to dryness the ether or gasoline solutions, obtained as directed in (b) and
(C), and dissolve the residue in 10-20 cc. of strong alcohol. To the alcoholic solution
add some strands of white silk and a little water and evaporate on the steam bath until
the alcohol has been removed or until the dye is taken up by the silk. The dyeing
test is sometimes unsatisfactory and in all cases a small portion of the alcoholic solu-
tion should be tested by treating with an equal volume of concentrated hydrochloric
acid and stannous chlorid solution. The common oil-soluble coal tar dyes are ren-
dered more red or blue by the acid and are decolorized by the reducing agent. Most
of the natural coloring matters become slightly paler with the acid and are little
changed by the stannous chlorid solution.

Separation of Coloring Matters in Pure Condition by Means of
immiscd3le solvents6.

4 preparation of sample.

(a) Water-soluble colors. — Proceed as directed under 2, omitting the fixation of
the color on wool, and obtain an aqueous solution as free as practicable from sus-
pended matter, alcohol, acids, alkalies and salts.

(b) Water-insoluble lakes. — If the sample is in solid form, treat the well divided
material with sufficient water to form a paste. Liquids require no preparation
except the removal of alcohol when present.

5 Mixtures of Orange I, Erythrosine, Indigo Carmine, Amaranth,

Tartrazine, Naphthol Yellow S, Ponceau 3R and
Light Green S F Yellowish.

The use of immiscible solvents for the separation of mixtures of coloring matters
usually involves a systematic fractionation since many of the dyes used do not differ
very greatly in their solubilities in the various solvents. When it seems probable
that only the 8 coal tar dyes permitted under the Federal Food and Drugs A. t
are present, the following abridged procedure may be used for their separation. For
this procedure the concentration of the dye solution should lie preferably between
0.01-0.05%. The solutions obtained in the examination of colored food products
pracl Lcally never require furl her dilution bul wit b commercial food colors care must
be taken that the concentration is not too high. Treat the sample, prepared as
directed in 4, with one half its volume of concent rated hydrochloric arid and ext ract
a few times with amyl alcohol. The use of the centrifuge is sometimes necessary

158 METHODS OF ANALYSIS [Chap.

to separate the layers. Designate the residual aqueous layer as A. Combine the
amyl alcohol extracts and wash with 4-5 portions of N/4 hydrochloric acid or until
this solvent extracts very little color. These washings will contain any Indigo
Carmine, Amaranth and Tartrazine present, the Indigo Carmine being removed in
somewhat larger proportion in the first washings than the other 2. With ordinary
concentration very little Ponceau will be removed. Designate these combined
washings as B.
g ORANGE I AND ERYTHROSINE.

Measure, if necessary, the amyl alcohol extract, under 5, then (1) Dilute with an
equal volume of petroleum ether or low boiling gasoline, and again wash several
times with N/4 hj'drochloric acid to extract Ponceau 3R and Naphthol Yellow S;
or, (2) Without dilution with gasoline, wash with o% salt solution until these 2 dyes
are extracted. Designate these washings as C. The Ponceau and Yellow having
been removed, the amyl alcohol, containing an equal volume of gasoline, is washed
a few times with water which will extract Orange I. This dye having been removed,
shake the solution, although the latter may appear almost colorless, with very dilute
sodium hydroxid solution to remove Erythrosine. If considerable Orange I is present,
some of it may contaminate the washings containing the Ponceau 3R and Naphthol
Yellow S, especially when these have been separated by means of N/4 hydrochloric
acid after the addition of gasoline.

7 INDIGO CARMINE, AMARANTH AND TARTRAZINE.

The presence of 2 or all 3 of these dyes is usually indicated by the appearance
of the N/4 hydrochloric acid washings, B, under 5. Evaporate the combined N/4
hydrochloric acid washings to dryness to remove the excess of hydrochloric acid and
dissolved amyl alcohol. Dissolve the residue in water, divide the solution and iden-
tify the constituent colors in the portions. To a portion of the slightly acidified
solution add a few decigrams of urea, warm and add 1 or 2 drops of sodium nitrite
solution. Indigo Carmine is converted into the pale yellow isatin sulphonate while
the other dyes are but little affected. The isatin compound is not ordinarily present
in sufficient concentration to tint the solution but it differs from Tartrazine also in
being much less readily extracted by amyl alcohol from strong acid solutions (less
than one half from 4N acid). The solution now contains the Amaranth or Tar-
trazine, or both, practically unaffected. Amaranth is much more quickly attacked
by most reducing agents than Tartrazine. Treat the solution, which should be neu-
tral or faintly acid (in the presence of sodium carbonate the reduction of the tar-
trazine takes place still more slowly), at room temperature with a dilute solution of
sodium hyposulphite (Na2S204), adding the latter very carefully, drop by drop, and
allowing sufficient time after the addition of each drop for the reduction to take
place. When the color shows that the Amaranth has been destroyed completely,
shake the mixture at once with air to oxidize the slight excess of hyposulphite before
it can react further on the Tartrazine.

To separate the Indigo Carmine heat to boiling another portion of the solution,
which should be neutral or faintly acid, and add dilute sodium hyposulphite solution,
drop by drop, until all the dyes are reduced. On shaking with air the Indigo Carmine
is quickly re-formed.

8 NAPHTHOL YELLOW S AND PONCEAU 3R.

Treat the N/4 acid solution or the salt solution, C. under 6. as the case may be,
containing the Ponceau and Naphthol Yellow S, with enough hydrochloric acid to
make it about 2N and shake out a few times with washed ethvl acetate8. Remove

XI] COLORING MATTERS IN FOODS 159

the Yellow from the combined ethyl acetate extracts by shaking with water. Naph-
thol Yellow S is almost colorless in strongly acid solutions, and its absence in wash-
ings, etc., must never be assumed until these have been made alkaline. Finally
separate the Ponceau 3R from the acid solution by shaking with amyl alcohol, and
then wash out the dye from this extract with a few small portions of water. If,
in the case of mixtures containing Orange I, the washings of the ethyl acetate, which
should contain only Naphthol Yellow S, become more red upon the addition of al-
kalies, combine, then (1) Make N/4 with hydrochloric acid and remove the contami-
nating Orange by shaking with amyl alcohol-gasoline mixture (1 to 1); or, (2) Treat
the combined washings with one fifth their volume of concentrated hydrochloric
acid, extract the dyes by shaking once with amyl alcohol, and remove the Yellow
by washing with several portions of 5% salt solution.

9 LIGHT GREEN S F YELLOWISH.

The original mixture, A, under 5, from which the above mentioned 7 colors have
been removed by adding acid and shaking out with amyl alcohol, may still contain
Light Green S F Yellowish, which will be colorless or nearly so in the acid solution.
To separate this dye treat the mixture with strong ammonia or potassium hydrox-
id solution until slightly alkaline, and neutralize with acetic acid. Any Green
present will now be apparent by the color of the mixture. Extract the color by
shaking with a few small portions of dichlorhydrin. Wash the dichlorhydrin extract
with a little water, then dilute with several volumes of benzene or carbon tetra-
chlorid, and remove the dye by shaking with water.

When coal tar dyes other than the 8 mentioned above are present, the solutions
obtained in this procedure will be found to contain a coloring matter which does not
correspond exactly in properties to one of the dyes named above. When coal tar
dyes other than these 8 are present, reference should be made to the larger works9.

Coal Tar Dyes in General.

10 basic dyes.

Most basic dyes may be separated from mixtures by making alkaline with sodium
hydroxid and shaking with ether10. Use the sample, prepared as in 4, for this pur-
pose. Separate the ether layer, which may or may not be colored, and shake with
2-5% acetic acid, which will take up any dye present, forming a colored solution.
Although the common basic colors undergo some alteration by this treatment11,
it may be used for the qualitative detection and separation of Methyl Violet B (451),
Magenta (448), Bismarck Brown (197), Malachite Green (427), and Rhodamine B
(504). With care Auramine (425) may also be separated in this way though it is
quickly decomposed on standing in alkaline solution.

11 ACID DYES.

The following short procedure is often convenient for the examination of mixtures
of acid dyes: Make the sample, prepared as in 4, the color concentration of which
does not vary greatly from 0.01-0.05%, strongly acid by adding one half its volume
of concentrated hydrochloric acid and shake with amyl alcohol. Sena r:\to the
amyl alcohol solution and wash by shaking with successive portions of one half its
volume of water, reserving the portions in separate test tubes or beakers. Because
of the acid dissolved in the amyl alcohol these washings will show a regular decrease
in acidity and the coloring matters will appear in maximum amount in the different
fractions according to their respective solubilities. Ponceau OR (10S) is washed
out chiefly while the acidity is still high, N/1 or above. Amaranth (107), Brilliant

160 METHODS OF ANALYSIS [Chap.

Scarlet (106) and Tartrazine (94) appear when the washings have an acidity between
N/1 and N/4; Orange G (14) and Soluble Blue (480) between N/2 and N/16; Palatine
Scariet (53), Ponceau 2R (55) and 3R (56), Naphthol Yellow S (4), Cochineal (706),
Costal Ponceau (64) and Azorubine A (103) between N/16 and N/256. When the acid
is practically all removed, Orange I (85), Orange II (86) and Croceine Orange (IS)
begin to wash out, and less readily, Orange IV (88) and Metanil Yellow (95). Finally
the unsulphonated coloring matters, such as Erythrosine G (516), Erythrosine (517)
and the Rose Bengals (520 and 523) are removed very slowly by water or not at all
when all traces of acid have been removed. Acid Yellow (8) and Brilliant Yellow
S (89) are not very uniform in composition. They are partially taken up by amyl
alcohol from acid solution and appear chiefly in the first washings. Indigo Carmine
(692) behaves somewhat similarly.

Identification of the Coal Tar Dyes12.

1 2 GENERAL.

The most widely used tests for the identification of coal tar dyes refer to the
changes produced with acids and alkalies. Other tests, based upon the behavior
with reducing agents, followed perhaps by treatment with oxidants or by separation
and identification of the reduction products13, and tests based upon oxidation of the
dye and treatment of the oxidation products14 are generally applicable. Spectro-
scopic methods are also used15.

13 COLOR CHANGES PRODUCED WITH ACIDS AND ALKALIES.

Transfer the separated coloring matter to wool (or silk in the case of oil-soluble
dyes) by boiling as directed in 2 (a) or 3. Care should be taken that the final dyeing
is made in a solution fairly free from foreign matter such as sugar or aromatic sub-
stances, which, adhering to the fiber, may modify the reaction. In most cases the
amount of color available is small and should not be dyed on too large a piece of wool
(or silk). Rinse thoroughly the dyed fibre in running water, dry, cut into small pieces
and place separately in the depressions of a white porcelain spot plate. Moisten the
pieces with the respective reagents employed. (For many coloring matters the
hue upon treatment with acids or alkalies varies markedly with the concentration
of the reagents and amount of dye present; therefore the unknown dye should be
compared with dyeings of known colors of approximately the same dye concentration
as shown by this appearance.)

The table under 14 shows the color changes produced by concentrated hydro-
chloric and sulphuric acids, 10% sodium hydroxid and 12% ammonium hydroxid
solutions on wool dyed with 0.1-0.5% of the respective coloring matters. Included
also are the reactions of the oil-soluble colors but these refer to dyeings on silk.
The dyes are arranged approximately according to hue. Brown is classed with
orange, black (gra}-) with violet.

XI]

COLORING MATTERS IX FOODS

161

14

Table 14.
Color reactions produced on dyed fibers by various reagents.

COLORING MATTER

HYDROCHLORIC
ACID

SULPHURIC ACID

SODIUM HYDROXID

AMMONIUM

HYDROXID

Rhodamine B

504

Orange

Yellow

Bluer

Bluer

Rose Bengal

523

Almost

decolorized
Red

Orange

Xo change

No change

Archil

710

Dull brown

Violet

Violet

Magenta

U8

Yellowish
brown

Dull brown

Decolorized

Paler

Acid Magenta

m

Almost
decolorized

Yellow

Decolorized

Decolorized

Palatine Red

62

Darker

Violet

Dull brown

Little change

Bordeaux B

65

Violet

Blue

Brown

Little change

Amaranth

107

Slightly

Violet to

Dull brown-

Little change

darker

brownish

ish

Azorubine A

10S

Little change

Violet

Red

Red

Erythrosine

517

Orange-yellow

Orange-yellow

No change

No change

Ponceau 6RB

169

Blue

Blue

Dull violet-
red
Brown

Little change

Ponceau 6R

108

Violet-red

Violet

Orange-red

Crystal

64

Violet-red

Violet

Dull brown

Little change

Ponceau

Ponceau 3R

56

Little change

Little change

Dull orange

Little change

Sudan 111*

143

Violet, then
brown

Green

Violet-red

Little change

Safranine

584

Greenish blue

Green

Red

Red

Brilliant

106

Red

Violet-red

Yellowish

Orange-red

Scarlet

brown

Ponceau 2R

55

Little change

Little change

Brownish
yellow7

No change

Palatine

53

Darker

Violet-red

Brownish

No change

Scarlet

yellow

Ervthrosine G

516

Yellow-orange

Yellow-orange

No change

No change

Sudan 11*

49

Red

Violet-red

Little change

No change

Sudan 1*

11

Orange-red

Red

Redder

No change

Cochineal

706

Little change

Little change

Violet-red

Violet-red

Bismarck

197

Redder,

Browner

Yellower

Yellower

Brown

darker

Bismarck

201

Redder,

Browner

Yellower

Yellower

Brown R

darker

Orange I

85

Violet

Violet

Red, dark

Red, dark

Orange 11

86

Red

Red

Dull red

No change

Croceiine

13

Orange-red

Orange

Slightly

No chi

Orange

darker

Orange G

U

Little change

Orange

Dull, brown-
ish red

No change

Orthotoluene-

Red

Violet

Little change

No change

azo-beta-

naphthyl-

amine*

Sudan G*

10

Orange-yellow

Brownish

', 'How

Orange-yellow

No change

Butter Yellow*

16

Violet-red

( >range-yellow

No change

No change

Aniline Yellow*

7

Brownish red

Orange-yellow

Little change

No change

Aminoazo-

Dull orange

Orange-yellow

Little change

No change

ortho-tolu-

ene*

Oil-soluble.

162

METHODS OF ANALYSIS

[Chap.

14

Table 14. — Continued.

COLORING MATTER

HYDROCHLORIC
ACID

SULPHURIC ACID

SODIUM HTDROXID

AMMONIUM
HTDROXID

Fluoresceine

510

Little change

Little change

Green flu-
orescent

Green flu-
orescent

Metanil Yellow

95

Violet-red

Violet

No change

No change

Azoflavine

92

Violet-red

Violet-red

Dull brown

Little change

Acid Yellow

8

Red

Orange

Little change

No change

Brilliant

89

Violet-red

Violet-red

Little change

Little change

Yellow S

Tartrazine

94

Slightly
darker

Slightly
darker

Little change

Little change

Naphthol

4

Almost

Very pale,

No change

No change

Yellow S

decolorized

dull brown

Auramine

425

Decolorized

Almost

decolorized

Decolorized

Paler

Turmeric

707

Red

Reddish
brown

Orange

Orange

Quinoline

667

Slightly

Brownish

Slightly

Little change

Yellow

darker

yellow

paler

Naphthol

398

Yellowish

Brownish

No change

No change

Green B

yellow

Guinea Green

433

Pale orange-

Pale, dull

Decolorized

Decolorized

B

yellow

vellow

Light Green SF

435

Pale orange-

Pale, dull

Decolorized

Decolorized

Yellowish

yellow

yellow

Night Green 2B

438

Pale orange-
yellow

Pale, dull
yellow

Decolorized

Paler

Malachite

427

Almost

Almost

Decolorized

Decolorized

Green

decolorized

decolorized

Erioglaucine A

436

Yellow

Pale, dull
yellow or
brown

Slightly
darker

Little change

Patent Blue A

442

Pale orange-
yellow

Pale or dull
brown

Little change

Little change

Soluble Blue

480

Paler

Brown

Pale reddish

Almost decol-
orized

Indigo Carmine

692

Slightly

Slightly

Greenish yel-

Greenish blue

darker

darker

low

Formyl Violet

468

Pale orange-
yellow

Pale, dull
orange

Decolorized

Decolorized

Methyl Violet B

451

Yellowish

Yellowish

Decolorized

Almost decol-
orized
Pale reddish

Nigrosine, sol-

602

Dull bluish

Dull greenish

Brownish red,

uble

paler

15 SPECIAL TESTS FOR COAL TAR DYES PERMITTED7 UNDER THE FEDERAL

FOOD AND DRUGS ACT.

The dyes, given in 5, are sufficiently characterized in most cases by the solubilities
shown in their separation and by the color changes given by acids and alka'ies on
the dyed fiber. This is especially true with Amaranth, Tartrazine, and Orange I.
By treatment with reducing agents such as stannous chlorid, titanous chlorid, zinc
dust or sodium hyposulphite in acid solution, Indigo Carmine, Amaranth, Tartra-
zine, Ponceau 3R and Orange I are decolorized. With Indigo Carmine the color
returns on shaking with air, most readily on warming, or on the addition of oxidiz-
ing agents such as ferric chlorid or potassium persulphate. Excess of the reducing
agents must of course be avoided. With the last 4 named dyes the color is not re-
stored. Dilute solutions of Light Green S F Yellowish, Naphthol Yellow S and

XI] COLORING MATTERS IN FOODS 163

Erythrosine become paler or colorless with acids so that the effects of acid reducing
agents are not so readily apparent. Neutral solutions of Naphthol Yellow S are
decolorized by sodium hyposulphite and other reducing agents, the color not return-
ing with air or oxidants. An evanescent deepening of the shade may take place
immediately upon the addition of the hyposulphite. Erythrosine and Light Green
S F Yellowish become paler with sodium hyposulphite, the color being partially
restored upon the addition of potassium persulphate.

In hot solutions containing an excess of sodium tartrate the dyes named
are readily decolorized by titanium trichlorid18. In the case of Indigo Carmine if
the reducing agent has been added carefully and an excess avoided, the blue color
readily returns on shaking with air. With Erythrosine and Light Green S F Yel-
lowish the color is scarcely restored by air but on cooling and adding potassium
persulphate returns imperfectly. The reduction products of the other dyes do
not give colored solutions again on oxidation disregarding a slight yellowish or
brownish tint that may sometimes appear.

Indigo Carmine is extracted in small proportions from slightly acid solutions by
shaking with dichlorhydrin. Most of the other common bluish dyes are triphenyl-
methane derivatives and are relatively more soluble in this liquid than in the aque-
ous layer. A small portion (1 cc.) of the solution obtained in the separation, 5,
may be used directly.

Ponceau 3R gives in neutral or faintly acid solutions a bluish red, flocculent pre-
cipitate with barium chlorid or acetate, practically all of the dye being removed from
solution. Some of the solution obtained in the separation, 5, may be used in this
test, first neutralizing the free hydrochloric acid with sodium acetate; or better, it
may be evaporated to dryness on the steam bath to remove the acid and the residue
taken up with a little water. The solution should contain 0.005% or more of the
dye.

Naphthol Yellow S, in solutions containing an excess of ammonia or sodium car-
bonate, becomes intensely rose-red on the addition of sodium hyposulphite, the color
gradually fading again as complete reduction takes place.

Erythrosine differs from most of the common dyes by containing iodin. To test
for this, acidify the solution with sulphuric acid, shake with ether, separate the
ether solution of the color and evaporate to dryness in a platinum dish after the
addition of a few drops of sodium carbonate solution or sufficient to form the deep
red sodium salt. Hold the dish containing the residue in the Bunsen flame until
organic matter is destroyed, take up the residue with water, acidify with sulphuric
acid and test for iodin in one of the usual ways, such as with chlorin water and carbon
disulphid or tetrachlorid, or with starch paste and an oxidizing agent. It is useless
to test for iodin with very small amounts of dye but in most cases sufficient coloring
matter can be separated from the food product to give satisfactory results.

16 Natural Coloring Matters.

The natural coloring matters as a class show much less tendency to dye animal
fiber than do the common synthetic colors. In many cases the crude products used
contain a number of colored substances and a complete separation can scarcely be
attempted. Most of the natural coloring matters, in dilute solution, are sensitive
to alkalies, some to acids, hence such reagents must be used with care.

164 METHODS OF ANALYSIS [Chap.

SEPARATION OF NATURAL COLORING MATTERS.

1 7 Extraction with Ether from Neutral Solutions.

From neutral solutions ether extracts Carotin, Xanthophyll (the pigment found in
leaves, fats and oils, egg yolk, carrots, etc.), the coloring matter of tomatoes and
paprika and green Chlorophyll. The coloring matter remains in the ether solution
on shaking with dilute sodium hydroxid solution or dilute hydrochloric acid, no
apparent change taking place although chemically the substances may be altered
more or less by this treatment.

18 Extraction with Ether from Acid Solutions.

From slightly acid solutions ether extracts very readily and completely the
coloring matter of Alkanet, Annatto, Turmeric, and the red dyewoods, Sandalwood,
Camwood and Barwood. It extracts in large proportion the flavone coloring matters
of Fustic, Persian Berries (after hydrolysis), and Quercitron as well as the coloring
matter of Brazilwood and the green derivatives formed from Chlorophyll by alkaline
treatment. It extracts in relatively small amount the coloring matters of Logwood,
Archil, Saffron and Cochineal. The coloring matters of this group are readily re-
moved from ether by shaking with alkaline solutions but in most cases rapidly
undergo chemical change.

19 Extraction with Amyl Alcohol from Acid Solutions.

From slightly acid solutions amyl alcohol extracts largely the coloring matters of
Logwood, Archil, Saffron and Cochineal. [From ammoniacal Cochineal (Carmine)
the ordinary coloring matter is readily re-formed upon standing with hydrochloric
acid.] Amyl alcohol extracts in relatively small proportions Caramel and the Antho-
cyans constituting the red coloring matter of the most common fruits.

IDENTIFICATION OF NATURAL COLORING MATTERS.

20 REAGENTS.

(a) Hydrochloric acid. — Sp. gr. 1.20.

(b) 10% sodium or potassium hydroxid solution.

(C) Sodium hyposulphite solution. — A freshly prepared 5% solution of "Blankite",
sodium hyposulphite (Na2S20,i).

(d) 0.5% ferric chlorid solution.— Freshly prepared but may be made by diluting a
10% stock solution.

(e) 10% potassium or ammonium alum solution.

(f ) 5% uranium or sodium uranium acetate solution
(J*) Sulphuric acid. — Sp. gr. 1.84.

21 PROCEDURE.

Relatively few good tests are known for the common natural colors. Some of
their most useful analytical properties17 are tabulated in 22. In general these tests
should be applied to the somewhat purified solutions of the coloring matter obtained
as indicated in 17, 18 or 19.

Evaporate ether solutions to dryness, warm the residue with a little alcohol and
dilute the alcoholic solution with water. Apply the reagents as stated below:

XI] COLORING MATTERS IN FOODS 165

Hydrochloric acid. — Add concentrated acid (sp. gr. 1.20) to the solution, first
1 or 2 drops, then a large excess, equal to 3-4 times the volume of the solution.

Sodium hydroxid {-potassium hydroxid). — Make the solution slightly alkaline by
adding a drop of the 10% sodium hydroxid solution. A 10% solution of potassium
hydroxid in methyl alcohol must be used for the "brown phase reaction" for chloro-
phyll, described in 23, and may also be employed for the other tests.

Sodium hyposulphite. — Add the sodium hyposulphite solution drop by drop.

Ferric chlorid. — Add a small amount of the 0.5% ferric chlorid solution to the
solution to be tested. The reagent must be added very carefully, a small drop at a
time, as the colorations are not obtained in all cases when an excess is used.

Alum. — Add to the test solution one fifth its volume of the 10% potassium or
ammonium alum solution.

Uranium acetate. — Add the 5% uranium acetate solution drop by drop to the solu-
tion to be tested.

Concentrated sulphuric acid on the dry color.— Evaporate a small amount of the
solution or of the coloring matter in a porcelain dish. Cool thoroughly and treat
the dry residue with 1 or 2 drops of cold, concentrated sulphuric acid. The color-
ations are in some cases extremely fugitive and may be observed only the instant
the acid wets the residue.

The properties of pure preparations of the various natural coloring matters are
described, for the most part, by Rupe18. Properties of the Chlorophylls and
Carotinoids are given by Willstatter and Stoll19. Those of the coloring matters of
the Corn Flower, Rose, Pelargona Flower, Larkspur, Cranberry, Whortleberry and
Purple Grape are described by Willstatter20.

166

METHODS OF ANALYSIS

[Chap.

<

^c

CVJ
CM

2

g£«
k < d

£* =

_a
tc

||

>>

-co

Violet-blue
Violet-blue

E-

•<;

as;
o c

Z oo

«

D

& bO

- a

-(-5 • —

OT3

>

-a

OQ

O «

>*

o

D
J
O

a

s

<

Rose-red
(change
rather

slow)

Rose-red
(change

rather
slow)

a
2 „

° 5

J o

BB

Si J

s s

«■

a

b

Dark shades
of violet,
brown or
black (the
first hue of-
ten evanes-
cent)

Dark shades of
violet, brown
or black (the
first hue of-
ten evanes-
cent)

SODIUM

HYPOSULPHITE

SOLUTION

Almost decol-
orized, color
returning
imperfectly
by reoxida-
tion

Anthrocyani-
dins derived
by hydroly-
sis, almost
completely
decolorized

Decolorized,
color return-
ing when
shaken with
air. Reac-
tion more
easily seen
in alkalino
solution

SODIUM
HYDHOXID
SOLUTION

Violet to
violet-blue

Violet-red

Change to
green, dull
blue or
slate col-
or, usually
very
quickly,
becoming
browner by
oxidation

Deep blue

Blue

a

o
<
o

5
o

->
H
o

0
K

a

Deep red with
excess of
acid

Deep red with
excess of
acid

o

a

°&
.si

K

W

f*
H
■<
5
0

5

o

>4

O
o

Logwood
Redwoods

(Brazilwood,
Sandalwood,
Camwood and
Barwood)

Anthocvans of

red fruit col-
ors

Alkanet

\3

o

<

XIJ

COLORING MATTERS IN FOODS

167

4)

s

Red

Yellow
to orange

Blue

Blue, reaction

obtained
with difficul-
ty

0
4)
4>

o

Somewhat
browner

Orange colora-
tions

Not affected

Little
change

More strong-
ly yellow;
Fustic, de-
veloping a
green flu-
orescence

Little
change

Slightly darker

No marked

change

Perhaps

somewhat

browner
No marked

change.

Perhaps

somewhat

browner

Olive-green or
black colora-
tions

No marked
change.
Perhaps
somewhat
browner

4)

s

03

o

o

No marked

change
Little affected

Little affected

Little affected

Little affected
Little affected

45

"a

a

: >-.

43

53

43

<x>

>

Orange-brown

Bright-yellow

Remains
yellow

Little or no
change

"Brown
phase re-
action", 23

Little
change
or slightly
deeper
brown

Little or no

change
Remains

orange.

Little

change

Orange-red or
carmine-red
on addition
of several
volumes o f
concentrated
acid

Becomes in-
tensely yel-
low with 2-4
volumes of
concentrated
acid

Little or no
change

Little change.

Perhaps

slightly

paler
More brownish

Little or no
change

c

c
c

-

<

3 t

3 %

i c

Turmeric (solu-
tion in ether
or alcohol
characterized
by pure yel-
low color and
light green
fluorescence)

Flavone colors
of Fustic, Per-
sian Berries,
Quercitron,
etc.

Saffron

3 c

- 2 c
"8 E

> C

phyll
Caramel

168 METHODS OF ANALYSIS [Chap.

Special Tests for Natural Coloring Matters.

23 chlorophyll.

The "brown phase reaction"21 may be useful for the characterization of Chloro-
phyll, when this has not been previously treated with alkalies. Treat the green
ether or petroleum ether solution of the coloring matter with a small amount of
10% solution of potassium hydroxid in methyl alcohol. The color becomes brown
returning to green in a few minutes.

ANNATTO.

24 Leach Test-.

Pour on a moistened filter an alkaline solution of the color obtained by shaking out
the oil or melted and filtered fat with warm, dilute sodium hydroxid solution. If
Annatto is present, the filter paper will absorb the color so that; when washed with
a gentle stream of water, it will remain dyed a straw color. Dry the filter and add a
drop of stannous chlorid solution. If the color turns pink the presence of Annatto
is confirmed.

25 TURMERIC.

Carry out the highly characteristic reaction of Curcumine (Turmeric) with boric
acid as follows: Treat the aqueous or dilute alcoholic solution of the color with
hydrochloric acid until the shade just begins to appear slightly orange. Divide
the mixture into 2 parts and add some boric acid powder or crystals to 1 portion.
A marked reddening will be quickly apparent, best seen by comparison with the
portion to which the boric acid has not been added. The test may also be made by
dipping a piece of filter paper in the alcoholic solution of the coloring matter, drying
at 100°C, then moistening with a weak solution of boric acid to which a few drops
of hydrochloric acid have been added. On drying again a cherry-red color will be
developed.

26 COCHINEAL.

When the presence of Cochineal is suspected, acidify the mixture with one third
its volume of concentrated hydrochloric acid and shake with amyl alcohol. Wash
the amyl alcohol solution of the coloring matter 2-4 times with equal volumes of
water to remove hydrochloric acid, etc. Dilute the amyl alcohol with 1-2 volumes of
gasoline and shake with a few small portions of water to remove the color. Sepa-
rate the solution into 2 portions. To the first add, drop by drop, 5% uranium ace-
tate solution, shaking thoroughly after each addition. In the presence of cochineal
a characteristic emerald-green color is produced23. The green coloration with
uranium salts is not developed in the presence of much free acid. Therefore add a
little sodium acetate before making this test or a correspondingly large amount of
uranium acetate must be added. To the second portion add a drop or so of ammon-
ium hydroxid, and, in the presence of Cochineal, a violet coloration results. This,
however, is not so sensitive to small amounts as the first test and many fruit i
give tests hardly to be distinguished.

As cochineal lakes very often contain tin, further examination for this metal
should always be made when water-insoluble cochineal Compounds appear to be
present.

XII COLORING MATTERS IN FOODS 169

BIBLIOGRAPHY.

1 Schultz. Farbstofftabellen. 5th German ed., 1911-14.

2 Abs. Z. anal. Chern., 1885, 24: 625; 1889, 28: 639; Conn. Agr. Exp. Sta. Rept.,
1899, (11), p. 130.

3 J. Am. Chem. Soc, 1905, 27: 25.

4 Abs. Z. anal. Chem., 1896, 35: 397.

5U. S. Bur. Chem. Bull. 65, p. 152; Ann. fals., 1910, 3: 293; U. S. Bur. Chem.
Circs. 25 and 63; Abs. Chem. Zentr., 1898, (2), 943.

6 U. S. Bur. Chem. Circs. 25 and 63; Allen. Commercial Organic Analysis. 4th
ed., 1909-14, 5; Leach. Food Inspection and Analysis. 3rd ed., 1913; Girard and
Dupre. Analyse desMatieres Alimentaires et Recherches deleur Falsification. 1894;
J. pharm. chim., 6th ser., 1901, 13: 175; U. S. Bur. Animal Industry Circ. 180.

7 U. S. Dept. Agr., F. I. Ds. 76 and 164.

8 U. S. Bur. Chem. Bull. 162, p. 57.

9 Heumann. Die Anilinfarben und ihre Fabrikation. 1888-1906; Green. Sys-
tematic Survey of the Organic Colouring Matters. 2nd ed., rev., 1904, based on the
German of Schultz and Julius; Schultz. Farbstofftabellen. 5th German ed., 1911-
14; Allen. Commercial Organic Analysis. 4th ed., 1909-14, 5; Mulliken. Identifi-
cation of Pure Organic Compounds. 1910, 3.

10 Abs. Z. anal. Chem., 1887, 26: 100; 1888, 27: 232.
nBer., 1913, 46: 2131; 1914, 47: 1881.

12 Abs. Z. anal. Chem., 1887, 26: 100; 1888, 27: 232; Chem. Ztg., 1898, 22: 437;
U. S. Bur. Chem. Circ. 63; Green. The Identification of Dyestuffs on Animal Fibres.
Rev. ed., 1913.

13Ber., 1888, 21: 3471.

14 U. S. Bur. Chem. Circ. 114.

15 Formdnek. Spektralanalytischer Nachweiss kiinstlicher Organischer Farb-
stoffe zum Gebrauche bei wissenschaftlichen und gewerblichen Untersuchungen.
1900; Form&nek und Grandmougin. Untersuchung und Nachweiss Organischer
Farbstoffe auf Spectroskopischem Wege. 2nd ed., 1908-13.

16 Knecht and Hibbert. New Reduction Methods in Volumetric Analysis. 1910.

17 U. S. Bur. Chem. Circs. 25 and 63; Allen. Commercial Organic Analysis. 4th
ed., 1909-14, 5; Leach. Food Inspection and Analysis. 3rd ed., 1913.

18 Rupe. Die Chemie der Natiirlichen Farbstoffe. 1900-09.

19 Willstatter and Stoll. Untersuchungen liber Chlorophyll, Methoden und
Ergebnisse. 1913.

20Sitz. preuss. Akad., 1914, 12: 402.

21 Ber. botan. Ges., 1896, 14: 16; Willstatter and Stoll. Untersuchungen iiber
Chlorophyll, Methoden und Ergebnisse. 1913.

22 Leach. Food Inspection and Analysis. 3rd ed., 1913, p. 536.

23 Girard and Dupre. Analyse des Maticres Alimentaires et Recherches de leur
Falsification. 1894.

1

XII. METALS IN FOODS.
ARSENIC1.— TENTATIVE.

REAGENTS.

(a) Nitric and sulphuric acids, arsenic-free. — Specific gravities 1.42 and 1.84,
respectively.

(b) Sulphuric acid (1 to 2).

(C) Zinc, arsenic-free. — Stick zinc broken into pieces approximately 1 cm. in
length.

(d) Lead acetate paper. — Heavy filter paper soaked in 20% lead acetate solution,
dried and cut into pieces about 4.5 by 16 cm.

(e) Lead acetate cotton. — Absorbent cotton soaked in 5% lead acetate solution.

(f) Mercuric bromid paper. — Cut heavy, close-textured drafting paper (similar
to Whatman's cold pressed) into strips exactly 2.5 mm. wide and about 12 cm. long.
Soak for an hour in a 5% solution of mercuric bromid in 95% alcohol, squeeze out
the excess of solution and dry on glass rods. Cut off the ends of the strips before
using.

(&) 20% potassium iodid solution.

(h) Stannous chlorid solution. — Forty grams of stannous chlorid crystals made up
to 100 cc. with concentrated hydrochloric acid.

(1) Standard arsenic solution. — Dissolve 1 gram of arsenious oxid in 25 cc. of 20%
sodium hydroxid solution, neutralize with dilute sulphuric acid, add 10 cc. of the
concentrated sulphuric acid and dilute to 1 liter with recently boiled water. One
cc. of this solution contains 1 mg. of arsenious oxid (AS2O3).

Dilute 20 cc. of this solution to 1 liter. Fifty cc. of the latter solution when
diluted to 1 liter give a dilute standard solution containing 0.001 mg. of arsenious
oxid (As203) per cc. which is used to prepare the standard stains. The dilute solu-
tions must be freshly prepared immediately before use.

2 APPARATUS.

Use a 2 ounce wide-mouthed bottle as a generator. Fit this by means of a per-
forated rubber stopper with a glass tube, diameter 1 cm. and 6 cm. long, containing
a piece of the lead acetate paper rolled into a cylinder. Connect this tube by means
of a perforated rubber stopper with a similar tube filled with the lead acetate cotton,
squeezed to remove excess of the solution. The cotton in all lubes used should be
uniformly moist to obtain comparative stains. Connect the second tube by means
of a perforated rubber stopper with a narrow g!a>s tube, internal diameter 3 mm.
and 12 cm. long, containing a si rip of the mercuric bromid paper. See Fig. 7. Rubber
Stoppers used for connections must be free from any white coating.

3 PREPARATION- OF SOLUTION.

Weigh 5-50 grams of the finely divided and well mixed sample into a porcelain
casserole, the amount selected depending upon the character of the material and the
ease with which it is oxidized. With dry, highly nitrogenous substances employ
5 grams; pulped vegetables, 25 grams; liquids with low solid c intent like b.

171

172

METHODS OF ANALYSIS

[Chap.

vinegar, 50 grams. Add 10-15 cc. of the nitric acid, cover the casserole by setting
a watch glass inside the rim, convex side upward, heat until vigorous action is
over, cool and add 10 cc. of the concentrated sulphuric acid. Heat on a wire gauze
over a flame until the mixture turns dark brown or black, then add more nitric acid
in 5 cc. portions, heating between each addition until the liquid remains colorless
or yellow when evaporated until sulphur trioxid fumes are evolved. To remove

FIG. 7. APPARATUS FOR THE DETERMINATION OF ARSENIC.

completely all nitric or nitrous acid, evaporate to about 5 cc, cool, dilute with 10-
15 cc. of water and again evaporate until white fumes are evolved. Cool, dilute with
water, again cool, and make up with water to a definite volume (usually 25-100 cc,
depending upon the amount of sample taken and its arsenic content).

DETERMINATION.

Introduce 20 cc. of the solution or, if the amount of arsenic is large, an aliquot
containing not more than 0.03 mg. of As203, prepared as directed in 3, into th«

XII] METALS IN FOODS 173

generator of the apparatus described in 2 and add 20 cc. of the dilute sulphuric acid.
If the total volume is less than 40 cc, dilute to that volume with water and add

4 cc. of the 20% potassium iodid solution. Heat to about 90°C, add 3 drops of
the stannous chlorid solution and heat for 10 minutes. Cool the generator and its
contents in a pan containing water and ice; when cold add about 15 grams of the
stick zinc and connect the entire apparatus as described in 2. Keep the bottles in
ice water for 15 minutes, then remove from the bath and allow the evolution of gas
to proceed for an hour longer. Remove the sensitized paper and compare the stain
with similar ones produced under like conditions with known amounts of arsenic,
using portions of the standard arsenic solution, containing 0.001, 0.002, 0.005, 0.010,
0.015, 0.025 and 0.030 mg. of arsenious oxid (AS2O3), and adding such quantities of
water and sulphuric acid that the same volume and acid strength are maintained as
above.

TIN2.

5 Gravimetric Method. — Tentative.

Weigh 50-100 grams of the sample (depending upon the amount of dry substance
present and the relative ease with which the organic matter is oxidized) into an 800
cc. Kjeldahl flask and add 100 cc. of concentrated nitric acid. Allow to stand over-
night (this procedure being preferred if much fat or sugar is present) or else place
the flask on a wire gauze over a free flame and heat until the contents boil quietly.
Add 25-50 cc. of concentrated sulphuric acid (depending upon the amount of dry
substance present in the sample), and heat until white fumes are generated, cool
somewhat, then add 5-10 cc. of concentrated nitric acid and continue heating as
before. Repeat the addition of nitric acid until the solution remains clear after
boiling off the nitric acid and fumes of sulphur trioxid appear.

Add 200 cc. of water to the digested sample, prepared as directed above, and pour
into a 600 cc. beaker. Rinse out the Kjeldahl flask with 3 portions of boiling water
so that the total volume of the solution is about 400 cc. Cool, add concentrated
ammonia until just alkaline and then hydrochloric or sulphuric acid until the acidity
is about 2%. Place the beaker, covered, on a hot plate, heat to about 95°C. and pass
in a slow stream of hydrogen sulphid for another hour. Digest on the hot plate for an
hour and allow to stand 1-2 hours longer.

Filter the tin sulphid on an 11 cm. filter, similar in quality to No. 590, white ribbon,
S. & S. Wash alternately with 3 portions each of wash solution (100 cc. of saturated
ammonium acetate solution, 50 cc. of glacial acetic acid and 850 cc. of water) and
hot water. Digest the filter and precipitate in a 50 cc. beaker with 3 successive
portions of ammonium polysulphid, heat to boiling each time and filter through a
9 cm. filter. Wash the precipitate on the filter with hot water. Acidify the filtrate
with acetic acid, digest on a hot plate for an hour, allow to stand overnight and
filter through a double 11 cm. filter. Wash alternately with 2 portions each of the
wash solution and hot water and dry thoroughly in a weighed porcelain crucible.
Ignite over a Bunsen flame, very gently at first and later at full heat. The cru-
cible, partly covered, is then heated strongly with a large or Mekcr burner. Stan-
nic sulphid must be roasted gently to the oxid, which may be heated strongly with-
out loss by volatilization. Weigh as stannic oxid and calculate to metallic tin.

Volumetric Method*. — Tentative.

6 REAGENTS.

(a) Air-free wash solution. — Dissolve 20 grams of sodium bicarbonate in 2 liters
of boiled water and add 40 cc. of concentrated hydrochloric acid. This solution
should be freshly prepared before use.

174 METHODS OF ANALYSIS [Chap.

(b) N ' 1 100 iodin. — The solution must be standardized frequently against (d), con-
taining asbestos, and treated as described in 7, omitting the precipitation and boil-
ing with hydrochloric acid and potassium chlorate. To obtain exact results the
tin solution used for standardization should contain about the same amount of tin
as is found in the sample under examination.

(C) N/100 sodium thiosulphate.

(d) Standard tin solution. — Dissolve 1 gram of tin in about 500 cc. of concen-
trated hydrochloric acid. Make up to 1 liter with water. One cc. contains 1 mg.
of tin.

(e) Sheet aluminium. — Use sheet aluminium, about 30 gauge, free from tin.

7 DETERMINATION.

Proceed as directed in 5 to "Digest on the hot plate for an hour and allow to
stand 1-2 hours longer".

Filter the precipitate of tin sulphid upon asbestos in a Gooch crucible with a
detachable bottom, using suction. Wash the precipitate a few times and then
transfer the detachable bottom, asbestos pad, and tin precipitate to a 300 cc. Er-
lenmeyer flask. Remove all traces of the precipitate from the inside of the cru-
cible by means of a jet of hot water and a policeman, using a minimum amount of
water for washing.

Add 100 cc. of concentrated hydrochloric acid and 0.5 gram of potassium chlorate
to the flask. Boil for about 15 minutes, making about 4 more additions of smaller
amounts of potassium chlorate as chlorin is boiled out of the solution. Wash the
particles of potassium chlorate down from the neck of the flask with water and
finally boil to remove chlorin. Then add about 1 gram of the sheet aluminium to
dispel the last traces of chlorin.

Attach the flasks, in duplicate, as described below, to a large carbon dioxid gener-
ator. Pass the carbon dioxid through a scrubber containing water and then divide
into 2 streams by means of a Y-tube, each stream of carbon dioxid entering one of
the flasks by means of a long rubber tube connected with a bulbed tube, passed
through the rubber stopper of the flask and having its lower end near the surface of
the liquid in the flask. The carbon dioxid leaves the flask by a second bulbed tube,
the opening of which is near the top of the flask. This glass tube is connected by a
long rubber tube to a second glass tube about 10 inches long which is immersed in a
cylinder containing water. This gives a water-seal to the delivery tube and a pres-
sure against which the current of carbon dioxid must work. It also restrains any
strong flow of gas when not desired and permits a gas pressure in the Erlenmeyer
flask.

After the flasks are connected, raise the tubes in the water-seal cylinders so that
the generator has practically no pressure to overcome. Allow the carbon dioxid
to run for a few minutes. Drop the tubes to the bottom of the cylinders, creating
pressure in the flasks. Lift the rubber stoppers of the flasks alternately about a
dozen times, in order to force out any air remaining in the flasks. Slightly raise the
stopper on one of the flasks and quickly drop about 2 grams of sheet aluminium into
the flask. The aluminium should be folded into a strip about 1 cm. wide and slightly
bent so as to prevent it from striking directly on the bottom of the flask. After
the aluminium has entirely dissolved, raise the tubes in the water-seal cylinders so
as to allow carbon dioxid to pass through, place the flasks upon hot plates, and heat
to boiling. After boiling for a few minutes, remove the flasks from the hot plates
and cool in ice water (or cold running water), still maintaining within them an

XII] METALS IN FOODS 175

atmosphere of carbon dioxid. Lower the tubes in the cylinder. When cool, dis-
connect the flasks one at a time, putting a glass plug into the carbon dioxid inflow.
Wash the tubes, rubber stopper and sides of the flask with the air-free wash solution,
add starch paste and titrate at once with the N/100 iodin.

If it is desired to titrate by the excess method, run an excess of the N/100 iodin
into the flask while it is still connected with the carbon dioxid stream. Then wash
out the tubes and titrate the excess of iodin with the N/100 sodium thiosulphate.

The rubber connections should be washed with water after each determination.

8 COPPER.— TENTATIVE.

Destroy organic matter as directed in 5. Concentrate the sulphuric acid residue
by continued digestion to a volume of 10-15 cc, cool, dilute with a little water, trans-
fer to a 400 cc. beaker, rinse the Kjeldahl flask with water, adding the rinsings to the
contents of the beaker, dilute to about 200 cc. and boil to expel nitrous fumes. Cool,
render the solution slightly alkaline with ammonium hydroxid and boil to expel the
excess of ammonia. Add 5 cc. of concentrated hydrochloric acid for each 100 cc.
of solution, heat to incipient boiling and saturate the solution with hydrogen sul-
phid. Allow to stand on a steam bath for a few minutes until the sulphid flocculates,
filter and wash the precipitate with hydrogen sulphid water. Protect the precipi-
tate from contact with air as much as possible, use only hydrogen sulphid water for
washing and carry out this operation without interruption. Reserve the filtrate
for the determination of zinc, if necessary. Place the filter containing the copper
sulphid precipitate in a small flask, add 4-5 cc. of concentrated sulphuric acid and
the same amount of nitric acid and heat until white fumes appear. Continue the
oxidation, adding a little nitric acid from time to time, until the liquid remains
colorless upon heating to the appearance of white fumes. Cool, dilute with about
30 cc. of water, add an excess of bromin water and boil until all bromin is expelled.
Determine the copper as directed in VIII, 29, using N/100 sodium thiosulphate for
the titration.

9 ZINC— TENTATIVE.

Proceed as directed in 8 to the point indicated by the sentence "Reserve the fil-
trate for the determination of zinc, if necessary". Boil the filtrate, containing the
zinc, to expel hydrogen sulphid and to reduce the volume to about 250-300 cc, add
a drop of methyl orange and 5 grams of ammonium chlorid and make alkaline with
ammonium hydroxid. Add dilute hydrochloric acid, drop by drop, until the re-
action is faintly acid, then add 10-15 cc. of 50% sodium or ammonium acetate solu-
tion and pass in hydrogen sulphid for a few minutes until precipitation is complete.
Allow the precipitate to settle, filter, refiltcr, if necessary, until the filtrate is clear,
and wash the precipitate twice with hydrogen sulphid water. Dissolve the precipi-
tate on the filter with a little hydrochloric acid (1 to 3), wash the filter with water.
boil the filtrate and washings to expel hydrogen sulphid, cool and add a distinct
excess of bromin water. Then add 5 grams of ammonium chlorid and ammonium
hydroxid until the color, caused by free bromin, disappears. Add hydrochloric
acid (1 to 3), drop by drop, until the bromin color just reappears, then add 10 15 cc.
of 50% sodium or ammonium acetate solution and 0.5 cc. of 10% ferric chlorid solu-
tion, or enough to precipitate all the phosphates. Boil until all the iron is precipi-
tated. Filter while hot and wash the precipitate with water containing a little
sodium acetate. Pass hydrogen sulphid into the combined filtrate and washings

176 METHODS OF ANALYSIS

until all the zinc sulphid, which should be pure white, is precipitated, filter upon a
tared Gooch and wash with hydrogen sulphid water, containing a little ammonium
nitrate. Dry the crucible and its contents in an oven, ignite at a bright red heat,
cool and weigh as zinc oxid. Calculate the weight of metallic zinc.

BIBLIOGRAPHY.

1 U. S. Bur. Chem. Circ. 102; J. Soc. Chem. Ind., 1907, 26: 1115.

2 J. Assoc. Official Agri. Chemists, 1915, 1: 257.

3 Proc. Eighth Intern. Cong. Appl. Chem., 1912, 18: 35.

XIII. FRUITS AND FRUIT PRODUCTS.

1 PREPARATION OF SAMPLE.— TENTATIVE.

All samples received in open packages (i.e., not in sterile condition) must be trans-
ferred without delay to glass-stoppered containers and kept in a cool place. The
determination of alcohol, total and volatile acids, solids and sugars, particularly
in the case of fruit juices and fresh fruits, should be made at once as fermentation
is liable to begin very soon. Portions for the determinations of sucrose and reducing
sugar may be weighed and, after adding a slight excess of neutral lead acetate solu-
tion, kept without fermenting for several days if desired. The various products
are prepared as directed below.

(a) Juices. — Prepare the fresh juice by pressing the well pulped fruit in a jelly
bag and filtering through muslin.

(b) Jellies and sirups. — Mix thoroughly to insure uniformity in sampling. Weigh
60 grams into a 300 cc. flask, add water, dissolve by frequent shaking, then make up
to the mark with water, and use aliquots for the various determinations. If the
jelly contains starch or other insoluble material, mix thoroughly before taking the
aliquots.

(C) Fresh and dried fruits. — Pulp the whole, well cleaned fruit in a large mortar or
by means of a food chopper and mix thoroughly. In the case of stone fruits, remove
the pits and determine their proportion in a weighed sample.

(d) Jams, marmalades, preserves and canned fruits. — Pulp thoroughly the entire
contents of the jar or can, as directed under (C); with stone fruits remove the pits
and, if desired, determine their proportion in a weighed sample. In the exami-
nation of canned fruits it is often sufficient merely to examine the sirups in which the
fruits are preserved. In such cases the liquor may be separated and treated as pre-
scribed for juices.

2 ALCOHOL.— TENTATIVE.

Determine alcohol in 50 grams of the original material as directed under IX, 31 .

3 TOTAL SOLIDS.— TENTATIVE.

(a) Juices, jellies and sirups containing no insoluble matter. — Proceed as di-
rected in DC, 3, 5, 7 or 10, employing the sample prepared as directed in 1 (a) or (b).

(b) Fresh and dried fruits, jams, marmalades, preserves, canned foods and other
products containing insoluble matter. — Weigh about 20 grams of pulped fresh fruit,
or such an amount of fruit products as will give not more than 3-4 grams of dried
material; if necessary to secure a thin layer of the material, add a few cc. of water,
mix thoroughly, and dry as directed in IX, 3 or 4.

It is to be noted that certain State and Federal regulations require the moisture
in dried apples to be determined by drying for 4 hours at the temperature of boiling
water.

INSOLUBLE SOLIDS.

4 Direct Method. — Tentative.

Transfer 50 grains of the sample to a mortar by moans of warm water and macerate
thoroughly; then transfer to a muslin filter and wash thoroughly with about 500 cc.
of warm water, stirring the pulp thoroughly on each addition of water. This amount
of water is usually sufficienl to remove all soluble material. In extreme cases increase

177

178 METHODS OF ANALYSIS [Chap.

the washings to 1000 cc. Transfer the insoluble residue to an evaporating dish, dry
and weigh. If it is desired to determine the alcohol precipitate, 18, cool the filtrate,
make up to a definite volume and reserve for this determination.

5 I n direct Method. — Tentative.

Transfer 25 grams of the fruit product to a 250-500 cc. graduated flask, the size
of the flask depending upon the volume of insoluble matter present, add water,
shake thoroughly and make up to volume. Allow to settle and either filter or decant
the supernatant liquid. Determine the soluble solids in an aliquot, as directed in
3 (a). The fruit must be macerated thoroughly; the use of a mechanical shaker is
advisable. The percentage of insoluble solids is the difference between the per-
centage of the total solids and the percentage of soluble solids.

6 TOTAL ASH.— OFFICIAL.

Determine the ash as directed under VIII, 4, using 50 cc. of the solution of the
jelly or diluted sirup, 1 (b), evaporated to dryness, or 25 grams of juice or of fresh
or canned fruit, or 10 grams of jam, marmalade, preserves, or dried fruit.

7 ALKALINITY OF THE ASH.-TENTATIVE.

Into the platinum dish containing the ash introduce a measured excess of X 5
nitric acid, heat to boiling, cool and add a few drops of methyl orange. Carefully
rub up the ash with a rubber-tipped stirring rod and titrate the excess of acid with
N/10 potassium or sodium hydroxid. Express the result as the number of cc. of
N/10 acid required to neutralize the ash from 100 grams of the sample.

8 SULPHATE AND CHLORID.— TENTATIVE.

Wash the solution of the ash, obtained in 7, into a 50 cc. flask and make up to the
mark with water. Evaporate 25 cc. of this solution to dryness several times with con-
centrated hydrochloric acid, take up the final residue in a small amount of hot water,
filter, wash the paper with hot water, acidify the filtrate with a few drops of hydro-
chloric acid and determine the sulphate by precipitation with barium chlorid
solution. From the weight of barium sulphate calculate the sulphate present as
per cent of potassium sulphate.

In the other portion of the solution determine the chlorin as directed under HI, 15.
The nitric acid added before making the titration will, if it contain enough nitrous
oxid, completely destroy the red color of the methyl orange and leave a clear solu-
tion for the titration. Calculate the chlorin as per cent of sodium chlorid.

9 TOTAL ACIDITY.— TENTATIVE.

Dilute 25 cc. of the solution of jelly or diluted sirup, 1 (b), or 10 grams of juice or
fresh fruit, with recently boiled water to about 250 cc, or less if the sample be not
highly colored; titrate the acid with N/10 alkali, using phenolphthalein as an in-
dicator. In the case of highly colored products employ azolitmin solution or phenol-
phthalein powder [XVI, 25] on a spot plate instead of phenolphthalein solution.
Calculate the results as malic, citric or tartaric acid, specifying the acid used and
expressing the results in grams per 100 cc.

10 VOLATILE ACIDS.-TENTATrVE.

Dissolve 10 grams of the sample, dilute to 25 cc. and distil in a current of steam,
as directed under XVI, 27. Each cc. of N/10 alkali is equivalent to 0.0060 gram of
acetic acid.

XIII] FRUITS AND FRUIT PRODUCTS 179

11 FREE MINERAL ACIDS.— TENTATIVE.

Proceed as directed under XIX, 26, 27 or 28.

1 2 PROTEIN.— OFFICIAL.

Proceed as directed under I, 18, 21 or 23, using 5 grams of jelly or other fruit
product containing a large amount of sugar, or 10 grams of juice or fresh fruit and
a larger quantity of the sulphuric acid if necessary for complete digestion. Multi-
ply the percentage of nitrogen by 6.25 to obtain the percentage of protein.

SUCROSE.

13 By Polarization. — Official.

Determine by polarizing before and after inversion, as directed under IX, 22 or 23.

14 By Reducing Sugars Before and After Inversion. — Tentative.
Proceed as directed under VIII, 18.

15 REDUCING SUGARS.— TENTATIVE.

Proceed as directed under VIII, 25, expressing the results as invert sugar.

1S COMMERCIAL GLUCOSE. -TENTATIVE.

Proceed as directed under IX, 25.

1 7 DEXTRIN.— TENTATIVE.

Dissolve 10 grams of the sample in a 100 cc. flask, add 20 mg. of potassium fluorid,
and then about one fourth of a cake of compressed yeast. Allow the fermentation
to proceed below 25°C. for 2-3 hours to prevent excessive foaming, and then incu-
bate at 27o-30°C. for 5 days. At the end of that time, clarify with basic lead acetate
solution and alumina cream, make up to 100 cc. and polarize in a 200 mm. tube.
A pure fruit jelly will show a dextro or laevo-rotation of not more than a few tenths
of a degree. If a polariscope having the Ventzke scale be used and a 10% solution
polarized in a 200 mm. tube, the number of degrees read on the sugar scale of the in-
strument multiplied by 0.8755 will give the percentage of dextrin, or the following
formula may be used:

r> e j _x ■ C X 100 ... ,

Percentage of dextrin = in which

198 X L X W

C = degrees of circular rotation;

L = length of tube in decimeters;

W = weight of sample in 1 cc.

18 ALCOHOL PRECIPITATE.-TENTATIVE.

Evaporate 100 cc. of a 20% solution of jelly or diluted sirup, 1 (b), or of the wash-
ings from the determination of insoluble solids, 4, to 20 cc; add slowly, with constant
stirring, 200 cc. of 95% alcohol by volume and allow the mixture to stand overnight.
Filter and wash with 80% alcohol by volume. Wash the precipitate from the
filter paper with hot water into a platinum dish; evaporate to dryness; dry at 100°C.
for several hours and weigh; then burn off the organic matter and weigh the residue
as ash. Designate the loss in weight upon ignition as the alcohol precipitate.

The ash should be chiefly lime and not more than 5% of the total weighl of the
alcohol precipitate. If it is greater than this, some of the salts of the organic acids
have been brought down. Titrate the water-soluble portion of this ash with X 10
acid, as any potassium bitartrate precipitated by the alcohol can thus be estimated

180 METHODS OF ANALYSIS [Chap.

STARCH.

19 Qualitative Test. — Tentative.

First destroy the color of the jelly by treatment with sulphuric acid and potassium
permanganate solution and then test with iodin solution. Bring the solution of
jelly nearly to boiling, add several cc. of dilute sulphuric acid and then potassium
permanganate solution until all color is destroyed. The starch remains unaffected
by this treatment. The presence of starch is not necessarily an indication of its
addition as an adulterant. It is usually present in small amount in the apple, and
occasionally in other fruits, and unless it is found in the fruit product in consider-
able amount its presence may be due to these natural sources.

GELATIN1.

20 Qualitative Test. — Tentative.

The presence of gelatin in jellies and jams is shown by the increased content of
nitrogen. Precipitate a concentrated solution of jelly or jam with 10 volumes of
absolute alcohol and determine nitrogen in the dried precipitate as directed under

I, 18, 21 or 23.

AGAR AGAR.
QUALITATIVE TESTS.

21 By Microscopic Examination2. — Tentative.

Heat the jelly with 5% sulphuric acid, add a crystal of potassium permanganate
and allow to settle. If agar agar is present the sediment will be rich in diatoms
which can be detected by the use of the microscope.

22 By Precipitation3. — Tentative.

Cover 30 grams of the jam or jelly with 270 cc. of hot water, stir until thoroughly
disintegrated and boil for 3 minutes. Filter immediately, while still boiling hot,
through a filter paper of texture similar to No. 597, S. & S. In the presence of agar
agar a precipitate will form upon standing not longer than 24 hours. Filter,
wash with cold water and dissolve from the paper by means of a very small amount
of boiling water. Upon chilling this hot water solution a firm jelly will be formed
that can be examined by the touch. This method will detect 0.2% of agar agar with
certainty if the proportions of jam or jelly and water are strictly observed.

TARTARIC ACID— TENTATIVE.

23 PREPARATION OF SOLUTION.

Filter fruit juices and employ the filtrate directly. In the case of jellies filter
the solution, prepared as directed in 1 (b), and employ the filtrate. In the case of
sirups or substances containing insoluble matter like pulped fruit, jams, marmalades,
etc., weigh 50-100 grams, the amount selected being dependent upon the content of
solids, of the sample, prepared as directed in 1 (C) or (d), introduce into a 200 cc.
graduated flask, make up to the mark with water, allow to stand for an hour, shake at
frequent intervals, filter through a dry paper and use the filtrate.

24 DETERMINATION.

Determine the tartaric acid in 100 cc. of fruit juice or the same amount of a solu-
tion of the sample, prepared as directed in 23, employing the method given under XVI,
29, except that 20 cc. of alcohol are used in the precipitation instead of 15 cc.

XIII] FRUITS AND FRUIT PRODUCTS 181

MALIC ACID.

25 Method I. — Tentative.

(For fruit juices and similar products containing no tartaric acid and not
over 15% of sugars and in which the color does not interfere
with polarization.)

Filter the sample, if necessary to secure a solution which can be readily polar-
ized, and polarize with white light and a dichromate cell, using a 200 mm. tube if
possible.

If the sample contains free mineral acid, transfer a measured portion (75 cc. is a
convenient volume) to a 100 cc. graduated flask, add enough standard alkali, cal-
culated from the acidity as determined in 9, to neutralize the total acidity, dilute
to the mark, mix well and filter. If no free mineral acids are present, it is unneces-
sary to neutralize the sample. If neutralized, proper correction must be made for
dilution in making the final calculation.

Transfer 25 cc. of the sample, or a neutralized solution, to a flask graduated at 25
and 27.5 cc, add about 2.5 grams of powdered uranyl acetate, and shake vigorously
at frequent intervals for 3 hours, keeping the mixture well protected from light.
If all of the uranyl acetate dissolves, add more so that a small amount remains
undissolved at the end of 3 hours. Dilute the solution to the 27.5 cc. mark with
saturated uranyl acetate solution, mix well and filter, if necessary, through a folded
filter. Polarize, if possible, in a 200 mm. tube. If the solution is too dark to polarize
in a 200 mm. tube, a 100 or 50 mm. tube may be used. Multiply the reading by 1.1
to correct for the dilution.

Multiply the algebraic difference in degrees Ventzke between the 2 readings cal-
culated to the basis of a 200 mm. tube by the factor 0.036 to obtain the weight of
malic acid in the sample in grams per 100 cc.

Make all polarizations at the same room temperature with white light and with
a dichromate cell. Make at least 6 readings in each case and take an average of
these.

In the case of dark colored fruit juices which cannot be polarized readily, approxi-
mately quantitative results may be obtained by adding to the solutions a few drops
of bromin, shaking thoroughly and filtering just before polarization.

Method II. — Tentative.

(Approximate determination for fruit juices and similar products con-
taining no tartaric acid and more than 15% of sugars.)
t

26 PREPARATION OF SOLUTION4.

Weigh out 25 grams of the sample and transfer to a 600 cc. beaker with a little
95% alcohol by volume. Add alcohol a little at a time until 200 cc. have been added,
stirring the mixture well, and warming, if necessary, to insure solution of all alcohol-
soluble substances. Filter on a Buchner funnel, using suction, and thoroughly
wash the precipitated pectins and insoluble matter with 95% alcohol, disregarding
any slight turbidity which may appear in the filtrate after the washings have
been added. From 9, calculate the amount of N/4 barium hydroxid required
nearly to neutralize the acidity in the 25 grams of sample taken. To the com-
bined filtrate and washings in an Erlenmeyer flask add the calculated quantity of
barium hydroxid solution, stir until reaction is complete and then add 3-5 drops, or
more if required, of 50% barium acetate solution to insure- an excess of barium.
Make up the volume of the mixture to about 375 cc. (not less) with alcohol, and re-
flux until the precipitate settles readily after being shaken. This may require 3-4

182 METHODS OF ANALYSIS [Chap.

hours. Filter with suction and thoroughly wash the precipitate in the flask and
on the paper with 95% alcohol by volume. Transfer the portion on the filter to
the original flask, rinsing the paper with a jet of hot water. Digest the pre-
cipitate with hot water, containing 2 grams of sodium sulphate in solution, un-
til the reaction is complete, and boil until the barium sulphate precipitate settles
readily. Concentrate by evaporation, if necessary, and transfer to a 100 cc. vol-
umetric flask with a little hot water, cool, make up to volume with water and
filter.

27 DETERMINATION.

Transfer 25 cc. of the filtrate, obtained in 28, to a flask graduated at 25 and
27.5 cc, add about 2.5 grams of pulverized uranyl acetate and shake vigorously at
frequent intervals for 3 hours, keeping the solution well protected from light. If all
the uranyl acetate dissolves, add more so that a small amount remains undissolved
at the end of 3 hours. Dilute the solution to the 27.5 cc. mark with saturated uranyl
acetate solution, mix well, filter if necessary, and polarize in a 200 mm. tube, using
the same precautions as described in 25. Multiply the reading, calculated to the
basis of a 200 mm. tube, by 1.1 to correct for the dilution.

Polarize another portion of the filtrate, obtained in 28, which has not been treated
with uranyl acetate. Multiply the algebraic difference in degrees Ventzke between
the 2 readings, calculated to the basis of a 200 mm. tube, by the factor 0.036 to obtain
the weight of malic acid in grams per 100 cc. in the solution as obtained in 26.

Method III. — Tentative.
(Approximate determination for products containing tartaric acid.)

28 PREPARATION OF SOLUTION5.

Prepare the sample as directed under 26 up to the point of filtration and washing
of the barium malate precipitate, then dry the precipitate thoroughly and transfer
the portion on the filter to the original flask, rinsing the paper with a jet of hot
water. Digest the precipitate with hot water, transfer to a 100 cc. volumetric
flask with a little hot water, cool, make up to volume with water and filter to re-
move insoluble barium tartrate. This amount of water is sufficient to dissolve
barium malate up to amounts as large as approximately 0.9 gram in 100 cc. More
than 100 cc. of water must be used when more than 0.9 gram of barium malate
is present. The amount of barium tartrate dissolved by hot water is so small as to
affect only slightly the polarization after treatment with uranyl acetate.

29 DETERMINATION.

Proceed as directed in 27, using the solution prepared as directed in 28.

CITRIC ACIDn— TENTATIVE.
(Applicable in the presence of sugar and malic and tartaric acids.

30 REAGENTS.

(a) Barium hydroxid solution. — Approximately N/4.

(b) 50% barium acetate solution.

(C) Sulphuric acid (1 to 1) and (1 to 5).

(d) Potassium or sodium bromid solution. — Dissolve 15 grams of potassium bromid
in 40 cc. of water or 16 grams of sodium bromid in 50 cc. of water.

XIII] FRUITS AND FRUIT PRODUCTS 183

(e) 5% potassium permanganate solution.

(f) Ferrous sulphate solution. — Dissolve 20 grams of ferrous sulphate in 100 cc.
of water containing 1 cc. of concentrated sulphuric acid.

(£) Bromin water. — Freshly prepared, saturated solution.

31 DETERMINATION.

Proceed as directed in 26 up to "Filter with suction and thoroughly wash the
precipitate in the flask and on the paper with 95% alcohol by volume''. Transfer the
precipitate from the filter to the flask with a jet of hot water, boil until alcohol
can no longer be detected by odor, and add enough of the sulphuric acid (1
to 5) to precipitate all the barium originally added and to allow 2 cc. in excess.
Evaporate by careful boiling to a volume of 60-70 cc, cool and add 5 cc. of freshly
prepared saturated bromin water, or enough to show a distinct excess. Transfer
with water to a 100 cc. volumetric flask and dilute to the mark at standard
temperature. Mix thoroughly, allow the precipitate to settle and filter through
a dry paper. The precipitate may be separated by centrifugalizing and the super-
natant liquid decanted, if necessary. Pipette an aliquot of the filtrate, containing
not more than 250 mg. of citric acid, calculated from the total acidity of the sample,
into a 300 cc. Erlenmeyer flask. If possible, the amount of citric acid in the ali-
quot should exceed 50 mg. Add 10 cc. of the sulphuric acid (1 to 1) and 5 cc. of the
potassium or sodium bromid solution, mix, warm the flask in a water bath to48°-50°C.
and allow it to remain in the bath for 5 minutes. After removing from the bath add
rapidly from a pipette, drop by drop with frequent interruptions, 25 cc. of the 5%
potassium permanganate solution and shake vigorously, avoiding a temperature
during oxidation exceeding 55°C. Set the flask aside until the hydrated peroxid of
manganese begins to settle. The supernatant liquid should be dark brown, showing
an excess of permanganate; if an excess is not indicated, add more permanganate.
Shake, again set aside to settle and repeat this operation until the precipitate
assumes a yellow color and most of it has dissolved. Finally, while the solution
is still warm, remove the last undissolved portion of hydrated peroxid of manganese
precipitate and also the excess of bromin by adding, drop by drop, the clear ferrous
sulphate solution. Allow the solution to cool, shaking occasionally. If the opera-
tions have been properly conducted, a heavy white precipitate of pentabromacetone
is obtained which becomes crystalline on occasional shaking and in this condition
is entirely insoluble in water. Allow the mixture to stand overnight, collect it by
means of gentle suction on a tared Gooch crucible provided with a thin pad of asbestos,
previously dried over sulphuric acid in a vacuum desiccator, wash with water slightly
acidified with sulphuric acid and finally wash twice with water. Dry the precipitate
to constant weight over sulphuric acid in a vacuum desiccator, protecting the precipi-
tate from strong light. The weight of pentabromacetone multiplied by the factor 0.424
gives the equivalent weight of anhydrous citric acid (H3C6H5O7). Occasionally the
pentabromacetone is first obtained in the form of oily droplets. These become
crystalline on standing or on cooling and are usually discolored by negligible traces
of manganese or iron.

The above method may lie applied directly to the sample without previous pre-
cipitation of the citric acid as the barium salt when the amount of su^ar or other
permanganate reducing substances is not excessive. In this case begin the deter-
mination with the addition of 2 cc. of sulphuric acid (1 to 5) and the treatment
with bromin water.

32 METALS.-TENTATIVE.

Proceed as directed under XII.

184 METHODS OF ANALYSIS

33 PRESERVATIVES.— TENTATIVE.
Proceed as directed under X.

34 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

35 SWEETENING SUBSTITUTES.— TENTATIVE.
Proceed as directed under X, 12, 36 or 37.

BIBLIOGRAPHY.

1 Chem. Ztg., 1895, 19: 552.

2 Z. angew. Mikros., 1896, 2: 260.

3 Z. Nahr. Genussm., 1911, 21: 185.

4 J. Assoc. Official Agri. Chemists, 1915, 1: 480.

5 Ibid.; U. S. Bur. Chem. Bull. 162, p. 65.

6 Arch. Chem. Mikros., 1914, 7: 285; Abs. Z. Nahr. Genussm., 1915, 30: 309.

XIV. CANNED VEGETABLES.

1 PHYSICAL EXAMINATION1.— TENTATIVE.

Note carefully the external appearance of the packages to detect the presence of
"leakers", "swells" or "springers". In general the ends of sound tins of canned
vegetables are slightly concave. On opening the package note the relative pro-
portion of solid and liquid contents and the level of the solids and of the total con-
tents in the tin. Note the general appearance, odor, flavor, color and size of the
vegetables; appearance of the liquor or brine, whether clear or turbid, and the con-
dition of the inner walls of the container, especially as to blackening and corrosion.
In all instances the analyst should familiarize himself with the normal appearance,
odor, color, flavor and other properties of the product under examination. Care-
ful macroscopic or microscopic examination should be made for worm infestation,
mold, dirt, or other evidence of decomposition or filth.

2 PREPARATION OF SAMPLE.— TENTATIVE.

The preparation of the sample for analysis depends upon the character of the
product and the determinations to be made. Samples in which only the solid or
liquid portion is required should be treated as follows: Weigh the full can, open,
pour off the liquid, allow the solid portion to drain for a minute, re-weigh the can
and drained vegetables, then remove the solid portion and weigh the dry, empty
can. The method selected for draining the vegetables is dependent upon the nature
and condition of the sample. In most cases it is sufficient to cut around the cover
and before turning it back allow the liquor to drain through the slit. Whenever a
portion of the solid material would escape with the liquor by this procedure, drain
upon a piece of cheese-cloth. From the weights thus obtained determine the per-
centage of liquid and solid contents. If only the solid portion is required, separate
in a similar manner and grind thoroughly the drained vegetables in a mortar or
food chopper. If a composite of the solid and liquid portion is required, grind
thoroughly the contents of the can in a mortar or food chopper. In all cases mix
thoroughly the portion used and preserve the balance in glass-stoppered containers.
Unless the analysis is to be completed in a reasonably short time, determine the
moisture in a portion of the sample prepared as above and, in order to prevent decom-
position, dry the remainder and then expose to air until it becomes air-dry, grind, mix
thoroughly and preserve in glass-stoppered containers. A second moisture determi-
nation is required in this procedure.

3 MOISTURE.-TENTATIVE.

Dry a quantity of the sample, representing about 2 grams of dry material, as
directed in DC, 2.

4 ASH.— OFFICIAL.

Determine total ash as directed in VIII, 4.

5 SALT.-OFFICIAL.

|g ^Determine chlorin as directed under DH, 1 5, and express the result in terms of
sodium chlorid.

185

186 METHODS OF ANALYSIS

6 SUGARS.-TENTATIVE.

Determine reducing sugars and sucrose as directed in VIII, 58 and 59, varying
the weight of the sample employed according to its sugar content.

7 TOTAL ACIDS.— TENTATIVE.

Proceed as directed in XVI, 25. Express the result as citric acid; 1 cc. of X 10
alkali is equivalent to 0.0070 gram of crystallized citric acid.

8 VOLATILE ACIDS.-TENTATIVE.

Proceed as directed in XVI, 27. Express the results as acetic acid; 1 cc. of N 10
alkali is equivalent to 0.0060 gram of acetic acid.

9 PRESERVATIVES.— TENTATIVE.
Proceed as directed under X.

10 COLORING MATTERS— TENTATD7E.
Proceed as directed under XI.

"j 1 METALS.-TENTATIVE.

Proceed as directed under XII.

BIBLIOGRAPHY.

/U.S. Bur. Chem. Bulls. 125 and 151 ; U. S. Dept. Agr. Bull. 196; U. S. Bur. Chem.
Circ. 54; Research Laboratory, National Canners Association, Bull. 2.

XV. CEREAL FOODS.

WHEAT FLOUR.

1 MOISTURE.— OFFICIAL.
Determine moisture as directed in VIII, 2.

2 ASH.— OFFICIAL.

Determine ash as directed in VIII, 4, using 5 grams of the flour.

3 CRUDE FAT OR ETHER EXTRACT.— OFFICIAL.

Determine the ether extract as directed in VIII, 1 0. With fine flour the addition
of an equal weight of clean, dry sand is frequently necessary.

4 CRUDE FIBER.— OFFICIAL.
Determine crude fiber as directed in VIII, 68.

5 ACIDITY OF WATER EXTRACT.— TENTATIVE.

Weigh 18 grams of the flour into a 500 cc. Erlenmeyer flask and add 200 cc. of
carbon dioxid-free water. Place the flask, loosely stoppered, for an hour in a water
bath kept at 40°C, shaking occasionally. Filter upon a dry, folded filter, return-
ing the first 10-15 cc. of the filtrate to the filter. Titrate 100 cc. of the clear filtrate
with N/20 sodium hydroxid, using phenolphthalein as an indicator. Each cc. of
N/20 sodium hydroxid is equivalent to 0.05% acidity as lactic acid.

6 SUGARS.— TENTATIVE.

Determine reducing sugars and sucrose as directed in VIII, 58 and 59.

7 PROTE1N.-OFFICIAL.

Determine nitrogen as directed in I, 18, 21 or 23. Multiply the percentage of
nitrogen by 5.7 to obtain the percentage of protein.

ALCOHOL-SOLUBLE PROTEIN.

8 Method I. (By nitrogen determination) — Tentative.

Transfer 4 grams of the flour to a 150-200 cc. bottle or Erlenmeyer flask and add
100 cc. of 70% alcohol by volume, taking care that none of the material sticks
to the bottom of the container. Shake thoroughly 10-12 times at intervals of 30
minutes at room temperature, or shako continuously in a shaking machine for
an hour, and then set aside overnight. Shake thoroughly once more, allow to settle
and filter through a dry, folded filler, returning the first runnings to the filter until
a clear filtrate is obtained. Pipette 50 cc. of the filtrate, equivalent to 2 grams of
the sample, into a Kjeldahl flask, dilute with 100 cc. of water to prevent frothing
during digestion and determine nitrogen as directed in I, 18, 21 or 23.

187

188 METHODS OF ANALYSIS [Chap.

9 Method II. (By Polarization) — Tentative.

Millon's reagent. — Dissolve metallic mercury in an equal weight of concentrated
nitric acid and dilute the solution with an equal volume of water. The freshly
prepared solution must be used.

1 0 DETERMINATION.

Weigh 15.97 grams of the flour into a 300 cc. flask and add 100 cc. of alcohol fsp.
gr. 0.90). Shake at 30 minute intervals for 3 hours and then let stand overnight.
Filter through a dry, folded filter and polarize in a 200 mm. tube. Precipitate the
proteins in 50 cc. of the filtrate by the addition of 5 cc. of Millon's reagent. Shake,
filter and polarize the filtrate in a 200 mm. tube. Multiply the reading in degrees
Ventzke by 1.1 to correct for the dilution and deduct the product from the first
reading. This difference multiplied by 0.2 gives the per cent of gliadin1 nitrogen.

1 1 PROTEIN SOLUBLE IN 5 PER CENT POTASSIUM SULPHATE SOLUTION —TENTATIVE.

Weigh 6 grams of the flour into a 200 cc. flask and introduce exactly 100 cc. of
5% potassium sulphate solution. Shake at 30 minute intervals for 3 hours and
let stand overnight or, better still, agitate at moderate speed in a shaker for 3 hours,
let settle 30 minutes, filter and determine the nitrogen in 50 cc. of the filtrate as
directed in I, 18, 21 or 23.

12 GLOBULIN AND ALBUMIN (EDESTIN AND LEUCOSIN) AND AMINO NITROGEN2.—

TENTATIVE.

Weigh 10 grams of the flour into a 500 cc. Erlenmeyer flask, add 250 cc. of 1%
sodium chlorid solution, stopper the flask and shake thoroughly. Let stand, with
occasional shaking, for 3 hours, filter through dry paper and evaporate 100 cc. of
the filtrate to a small volume in a Kjeldahl digestion flask with 5 cc. of concentrated
sulphuric acid. Add the remainder of the sulphuric acid and determine the nitro-
gen as directed in I, 18, 21 or 23. To a second 100 cc. of the filtrate add 5 cc. of 20%
phosphotungstic acid solution, shake thoroughly, allow to settle and filter by de-
cantation. Wash slightly with water, concentrate the filtrate with 5 cc. of sul-
phuric acid in a Kjeldahl flask and determine the nitrogen (amino) as directed in
I, 18, 21 or 23. Deduct the amino nitrogen from the nitrogen found in the first frac-
tion to obtain the nitrogen as globulin and albumin3.

13 GLUTENIN.— TENTATIVE.

Deduct the sum of the potassium sulphate-soluble nitrogen, 11, and the alcohol-
soluble nitrogen, 8, from the total nitrogen, 7, and multiply the difference by 5.7.

14 COLD WATER-SOLUBLE EXTRACT-TENTATIVE.

Weigh 20 grams of the flour into a 500 cc. Erlenmeyer flask and add gradually
200 cc. of water at 10°C, shake vigorously when about 50 cc. of water have been
added and continue shaking during the addition of the remainder. Allow to Stand
at 10°C. for 40 minutes, shaking occasionally. Filter through a large, dry. coarse
filter paper, returning the first runnings to the filter until a clear filtrate is obtained.
Pipette 20 cc. of the clear filtrate into a tared dish, evaporate to dryness on a steam
bath, and dry to constant weight in an oven at 100°C. for pei 10 minutes.

XV] CEREAL FOODS 189

GLUTEN.

15 Bamihl Test. (Qualitative) — Tentative.

Place a very small quantity (about 1.5 mg.) of the flour on a microscope slide,
add a drop of water, containing 0.2 gram of water-soluble eosin in 1 liter, and mix
by means of a cover-glass, holding the latter at first in such a manner that it is raised
slightly above the slide, and taking care that none of the flour escapes from beneath
it. Finally allow the cover-glass to rest on the slide and rub it back and forth
until the gluten has collected into rolls. The operation should be carried out on
a white paper so that the formation of gluten rolls can be noted. Wheat flour, or
other flours containing gluten, show by this treatment a copious amount of gluten,
which absorbs the eosin with avidity, assuming a carmine color. Rye and corn
flour yield only a trace of gluten, and buckwheat flour no appreciable amount.
The preparations are best examined with the naked eye, thus gaining an idea of
the amount of gluten present. If the flour is coarse, or contains a considerable amount
of bran elements, as is true of buckwheat flour and low-grade wheat flour, the test
should be made after bolting, as the bran particles and coarse lumps interfere with
the formation of gluten rolls.

16 Quantitative Method. — Tentative.

Weigh 25 grams of the flour into a cup or porcelain mortar, add sufficient tap water
(about 15 cc.) to form a firm dough ball and work into a dough with a spatula or
pestle, taking care that none of the material adheres to the utensil employed. Allow
the dough to stand in water at room temperature for an hour, then knead gently
in a stream of tap water until the starch and all soluble matters are removed. This
operation requires approximately 12 minutes and should be performed over bolting
cloth or a horsehair sieve. To determine if the gluten is starch-free let 1 or 2 drops
of the wash water, obtained by squeezing the gluten, fall into a beaker containing
perfectly clear water. If starch is present a cloudiness appears. Allow the gluten
thus obtained to stand in water for an hour, then press as dry as possible between
the hands, roll into a ball, place in a tared, flat-bottomed dish and weigh as moist
gluten. Transfer to an oven, dry to constant weight at 100°C. (about 24 hours),
cool and weigh as dry gluten.

CHLORIN.

17 Qualitative Test. (Chlor in-Bleached Flours) — Tentative.

Extract 30 grams of the flour with gasoline and allow the latter to evaporate.
A small amount of oil remains. Heat a piece of copper wire in a colorless gas flame
until it is black andno longer colors the flame green. Dip the hot end of the wire
into the oil and again bring into the flame. If chlorin or bromin has been used as
a bleaching agent, a green or blue coloration is produced.

1 8 Quantitative Method. (Added Chlorin in Chlor in-Bleached Flours) — Tentative.

Weigh 20 grams of the flour into a flat-bottomed aluminium dish, 8-10 cm. in
diameter, and dry 5 hours in a boiling water or steam oven, transfer, with as little
exposure to the air as possible, to a continuous fat extractor, and extract for Hi hours
with anhydrous alcohol-free ether, which is also free from chlorin. Transfer (he
ether extract to a nickel dish and add 25 cc. of a solution containing 25 grams of
sodium hydroxid and 15 grams of sodium nitrate per liter. Place the dish on a
steam bath, evaporate to dryness and ignite in a muffle at a dull red heal until

190 METHODS OF ANALYSIS [Chap.

the contents are thoroughly charred. Extract the charred mass with 25 cc. of 1%
nitric acid and filter. Return the residue to the dish, char and again extract with
25 cc. of 1% nitric acid, filter, wash with hot water, return to the dish and ignite
to a white ash. Dissolve the ash in 5% nitric acid and add the solution to the filtrates
previously obtained. Determine the chlorin in the combined filtrates either gravi-
metrically, as directed in I, 16 (a), or volumetrically, as directed in III, 15, using
N/50 solutions for greater accuracy.

NITRITE NITROGEN.— TENTATIVE.

19 REAGENTS.

(a) Sulphanilic acid solution. — Dissolve 0.5 gram of sulphanilic acid in 150 cc. of
20% acetic acid.

(b) Alpha-naphthylamin hydrochlorid solution. — Dissolve, by heating, 0.2 gram
of the salt in 150 cc. of 20% acetic acid.

(C) Standard nitrite solution. — Dissolve 0.1097 gram of dry C. P. silver nitrite
in about 20 cc. of hot water, add 0.10 gram of C. P. sodium chlorid, shake until
the silver chlorid flocculates and make up to 1 liter. Draw off 10 cc. of the
clear solution and dilute to 1 liter. Each cc. of the last solution is equivalent to
0.0001 mg. of nitrogen as nitrite. [Cf. IV, 12 (d)]

The silver nitrite may be prepared as follows : To a cold solution of about 2
grams of sodium or potassium nitrite in 50 cc. of water, add a solution of silver
nitrate as long as a precipitate appears. Decant the liquid and thoroughly wash
the precipitate with cold water. Dissolve in boiling water. On cooling the silver
nitrite crystallizes out. Dry the crystals in the dark at ordinary temperature (pre-
ferably in a vacuum).

20 DETERMINATION.

(1) Select a series of 100 cc. volumetric flasks of uniform dimensions and color.
Place 2 grams of high-grade, nitrite-free flour in each; add approximately 70 cc. of
nitrite-free water and shake until the flour is thoroughly moistened. Add to these
flasks varying amounts of the standard sodium nitrite solution, so that a series of
comparison standards will be obtained having a range covering the probable nitrite
content of the unknown sample. Reserve 1 flask for a blank test. In order to
avoid making a large series of standards it is well to make a preliminary test to as-
certain the approximate nitrite content of the unknown. Where the quantity of
nitrite present is small, the nitrite solution in the flasks may be increased by 0.4
cc. each. Where bleaching is excessive, 1 gram of flour may be used throughout,
or the standards may be given a wider variation in nitrite content.

To each of 2 similar flasks add 2 grams of the flour and 90 cc. of water; shake
thoroughly and digest all the flasks, including the blank, in a water bath at 40°C.
for at least 15 minutes; add 2 cc. each of the sulphanilic acid and alpha-
naphthylamin hydrochlorid solutions to each flask. Continue the digestion at
40CC. for an additional 20 minutes. The color must be developed in all the flasks
under conditions as nearly uniform as possible. Make up to the marks with nitrite-
free water and compare the unknown with the series of standards. This may be
done in a large, white, enameled pan; the effect of the turbidity, due to the flour,
being minimized by the white background. The solutions should be allowed to
subside and should not be shaken during comparison; or,

(2) Weigh 20 grams of the flour into a 500 cc. Erlenmeyer flask, add 200 cc. of
nitrite-free water, previously warmed to 40°C, and close the flask with a rubber
stopper. Shake vigorously for 5 minutes and digest for an hour in a water bath,

XV] CEREAL FOODS 191

keeping the temperature of the liquid in the flask at 40°C. and shaking at 10 minute
intervals. Finally filter on a dry, nitrite-free, folded filter. Return the first run-
nings to the filter until a clear filtrate is obtained. Pipette 50 cc. of the filtrate and
50 cc. of the standard nitrite solution into small flasks; add to each, 50 cc. of water,
2 cc. each of the sulphanilic acid and alpha-naphthylamin hydrochlorid solutions,
shake and allow to stand an hour to bring out the color. Compare the 2 solutions
in a colorimeter. Divide the height of the column of the standard solution by that
of the solution of the sample to obtain the parts of nitrogen as nitrous acid (free
and combined) per million of flour.

21 GASOLINE COLOR VALUE.-TENTATTVE.

Place 20 grams of the flour in a wide-mouthed, glass-stoppered 120 cc. bottle and
add 100 cc. of colorless gasoline. Stopper tightly and shake vigorously for 5 minutes.
After standing 16 hours, shake again for a few seconds until the flour has been loos-
ened from the bottom of the bottle and thoroughly mixed with the gasoline, then
filter immediately on a dry 11 cm. paper into an Erlenmeyer flask, keeping the fun-
nel covered with a watch glass to prevent evaporation. In order to secure a clear
filtrate, a certain quantity of the flour should be allowed to pass over onto the paper
and the first portion of the filtrate passed through a second time. It will be found
convenient to fit the filter paper to the funnel by means of water and dry thoroughly
either by standing overnight in a well-ventilated place or by heating.

Determine the color value of the clear gasoline solution in a Schreiner or similar
colorimeter, using for comparison a 0.005% potassium chromate solution. This solu-
tion corresponds to a gasoline number of 1.0 and is conveniently prepared by dilu-
ting 10 cc. of a 0.5% solution to 1 liter. The colorimeter tube, containing the
gasoline solution, should first be adjusted so as to read 50 mm., then the tube
containing the standard chromate solution raised or lowered until the shades of yellow
in both tubes match. The reading of the chromate solution, divided by the reading
of the gasoline solution, gives the gasoline color value. The color value may be deter-
mined also in Nessler tubes, using for comparison potassium chromate solutions
of various dilutions prepared from a 0.5% solution and filling the tubes in all cases
to the height of 50 mm.

BIBLIOGRAPHY.

1 U. S. Bur. Chem. Bull. 152, p. 104.

2 Ibid., 81, p. 124.

3 Ibid., 122, p. 54.

XVI. WINES.

1 PHYSICAL EXAMINATION.— TENTATIVE.

Note the following: whether the container is "bottle full"; the appearance of
the wine, whether there is any sediment and if it is bright or turbid; condition when
opened, whether still, gaseous or carbonated; color and depth of color; odor, whether
vinous, acetous, pleasant or foreign; and taste, whether vinous, acetous, sweet,
dry or foreign.

2 PREPARATION OF SAMPLE— TENTATIVE.

If gas is contained in the wine, remove it by pouring back and forth in beakers.

Filter the wine, regardless of appearance, before analysis and determine immedi-
ately the specific gravity and such ingredients as alcohol, acids and sugars as are
liable to change through exposure.

3 SPECIFIC GRAVITY.— TENTATIVE.

20° C
Determine the specific gravity at -p — '■ by means of a pycnometer*

4 ALCOHOL.-TENTATIVE.

(a) By volume.— Measure 100 cc. of the liquid at 20°C. into a 300-500 cc. distilla-
tion flask, add 50 cc. of water, attach the flask to a vertical condenser by means of
a bent tube and distil almost 100 cc, making up to 100 cc. volume when cooled
to 20°C. Foaming, which sometimes occurs, especially with young wines, may be
prevented by the addition of a small amount of tannin. To determine the alcohol in

wines which have undergone acetous fermentation and contain an abnormal amount
of acetic acid, exactly neutralize the portion taken with sodium hydroxid solution
before distilling. This is unnecessary, however, in wines of normal taste and odor.

20° C

Determine the specific gravity of the distillate at -^ — '■ and obtain the correspond-
ing percentage of alcohol by volume from 5.

(b) Grams per 100 cc. — From the specific gravity of the distillate, obtained in
(a), ascertain from 5 the corresponding alcohol content in grams per 100 cc.

(C) By weight. — Divide the number of grams in the 100 cc. of distillate, as ob-
tained in (b), by the weight of the sample as calculated from its specific gravity.

(d) By i?nmersion refractometer. — The percentages of alcohol, as determined in
(a) and (C), may be verified by determining the immersion refractometer reading
of the distillate and obtaining, from 6, the corresponding percentages of alcohol.

193

194

METHODS OF ANALYSIS

[Chap.

Table 16.— Alcohol Table.

(Calculated by the U. S. Bureau of Standards from its experimental results1.)

For calculating the percentages of alcohol in mixtures of ethyl alcohol and water from their

specific gravities.

SPECIFIC

ALCOHOL

8PECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

G R A V IT Y

20° C.

Per cent

Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.99823

0 00

0.00

0.00

0.99492

2 25

1.79

1.78

0.99174

4 50

3.58

3 . 55

0.99815

0 05

0 04

0.04

0.99485

2 30

1.82

1.81

0.99168

4 55

3.62

3.59

0.99808

0 10

0.08

0.08

0.99477

2 35

1.86

1.85

0.99161

4 60

3.66

3.63

0.99800

0.15

0.12

0.12

0.99470

2.40

1.90

1.89

0.99154

4 65

3.70

3.67

0.99793

0.20

0.16

0.16

0.99463

2.45

1.94

1.93

0.99147

4 70

3.74

3.71

0.99785

0 25

0.20

0.20

0.99456

2 50

1.98

1.97

0.99140

4 75

3.78

3 75

0.99778

0 30

0.24

0.24

0.99449

2 55

2.02

2.01

0.99133

4 80

3.82

3.79

0.99770

0 35

0.28

0.28

0.99442

2 60

2.06

2.05

0.99127

4 85

3.86

3.83

0.99763

0 40

0.32

0.32

0.99434

2 65

2.10

2.09

0.99120

4 90

3.90

3.87

0.99755

0.45

0.36

0.36

0.99427

2 70

2.14

2.13

0.99113

4 95

3.94

3.91

0.99748

0 50

0.40

0.40

0.99420

2 75

2.18

2.17

0.99106

5 00

3.98

3.95

0.99741

0 55

0.44

0.44

0.99413

2 80

2.22

2.21

0.99100

5 05

4 02

3.99

0.99734

0 60

0.47

0.47

0.99405

2 85

2.26

2.25

0.99093

5 10

4.06

4.03

0.99726

0 65

0.51

0.51

0.99398

2 90

2.30

2.29

0.99087

5 15

4.10

4.07

0.99719

0.70

0.55

0.55

0.99391

2 95

2.34

2.33

0.99080

5 20

4.14

4.10

0.99711

0.75

0.59

0.59

0.99384

3 00

2.38

2.37

0.99073

5 25

4.1*

4.14

0.99704

0.80

0.63

0.63

0.99377

3 05

2.42

2.41

0.99066

5 30

4 .??

4.18

0.99697

0 85

0.67

0.67

0.99370

3 10

2.46

2.45

0.99060

5 35

4.26

4 22

0.99690

0.90

0.71

0.71

0.99362

3 15

2.50

2.49

0.90053

5 40

4.30

4 26

0.99682

0.95

0.75

0.75

0.99355

3 20

2.54

2.53

0.99047

5 45

4.34

4.30

0.99675

1 00

0.79

0.79

0.99348

3 25

2.58

2.57

0.99040

5 50

4.38

4.34

0.99667

1 05

0.83

0.83

0.99341

3 30

2.62

2.60

0.99033

5 56

4-42

4.38

0.99660

1 10

0.87

0.87

0.99334

3 35

2.66

2.64

0.99026

5 60

4.46

4.42

0.99652

1.15

0.91

0.91

0.99327

3 40

2.70

2. OS

0.99020

5 65

4.50

4.46

0.99645

1.20

0.95

0.95

0.99320

3 45

2.74

2.72

0.99013

5.70

4-54

4.50

0.99638

1.25

0.99

0.99

0.99313

3 50

2.78

2.76

0.99006

5 75

4.58

4.54

0.99631

1 30

1.03

1.03

0.99306

3 55

2.82

2.80

0.9S999

5 80

4.62

4.58

0.99623

1 35

1.07

1.07

0.99299

3 60

2.86

2.84

0.98993

5 85

4.66

4 62

0.99616

1 40

1.11

1.11

0.99292

3 65

2.90

2.88

0.98986

5 90

4.70

4 66

0.99608

1.45

1.15

1.15

0.99285

3 70

2.94

2.92

0.98980

5 95

4.74

4 70

0.99601

1.50

1.19

1.19

0.99278

3 75

2.98

2.96

0.98973

6 00

1 7B

4. is

4 74

0.99594

1.55

1.23

1.23

0.99271

3 80

3.02

3.00

0.98967

6 05

4 7S

0.99587

1.60

1.27

1.26

0.99264

3 85

3.06

3.04

0.98960

6 10

4.87

4 82

0.99579

1.65

1.31

1.30

0.99257

3 90

3.10

3. OS

0.9S954

6 15

4.91

4.86

0.99572

1.70

1.35

1.34

0.99250

3 95

3.14

3.12

0.98947

6 20

495

4.S9

0.99564

1.75

1.39

1.38

0.99243

4 00

3.18

3.16

0.98941

6 25

499

4.93

0.99557

1 80

1.43

1.42

ii !«f»236

4 05

3.22

3.20

0.9S934

6 30

5.03

4.97

0.99550

1.85

1.47

1.46

0.9922!)

4.10

3.26

3.24

O.Ovijn

6 35

5.07

5 01

0.99543

1 90

1.51

1.50

0.99222

4.15

3.30

3.28

0.9SM21

6 40

5.11

5.05

0.99535

1.95

1.55

1.54

0.99215

4.20

3.34

3.32

0.98915

6 45

5.15

5.09

0.99528

2 00

1.59

1.58

0.99208

4 25

S.S*

3.36

0.98908

6 50

5.19

5.13

0.99520

2 05

1.63

1.62

0.99201

4 30

3.42

3.39

O.OS'i 12

6 55

5.23

5.17

0.99513

2 10

1.67

1.66

0.99105

4 35

3.46

3 43

0 98895

6 60

5.27

5.21

0.99506

2.15

1.71

1.70

0.99188

4 40

3.50

3.47

ii 98889

6 65

5.31

5.25

0.99499

2.20

1.75

1.74

0.99181

4 45

3.54

3.51

0.98882

6 70

5 . 35

XV

IJ

WINES

195

5

Tabli

: 16.— Alcohol Table-

-Continued.

SPECIFIC
GRAVITY

ALCOHOL

specific

GRAVITY

ALCOHOL

SPECIFIC

ALCOHOL

20° C.

Per cent

Per

Grams

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

} Per

Grams

4°

bv volume

cent by

per

4°

by volume

cent by

per

4°

by volumeicent bv

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.98876

6 75

5.39

5.33

0.98566

9 25

7.41

7.30

0.98267

11.75

9.44

9.28

0.98870

6 80

5.43

5.37

0.98560

9 30

7.45

7.34

0.98261

11.80

9.48

9.31

0.98864

6 85

5.47

5.41

0.98554

9 35

7.49

7.38

0.98255

11.85

9.52

9.35

0.98857

6 90

5.51

5.45

0.98549

9 40

7.53

7.42

0.98250

11.90

9.56

9.39

0.98851

6.95

5.55

5.49

0.98543

9.45

7.57

7.46

0.98244

11.95

9.60

9.43

0.98845

7 00

5.59

5.53

0.98537

9.50

7.61

7.50

0.98238

12.00

9.64

9.47

0.98839

7 05

5.63

5.57

0.98531

9.55

7.65

7.54

0.98232

12 05

9.68

9.51

0.98832

7 10

5.67

5.60

0.98524

9 60

7.69

7.58

0.98226

12.10

9.72

9.55

0.98826

7.15

5.71

5.64

0.98518

9 65

7.73

7.62

0.98220

12.15

9.76

9.59

0.9S820

7.20

5.75

5.68

0.98512

9.70

7.77

7.66

0.98214

12 20

9.80

9.63

0.98813

7 25

5.79

5.72

0.98506

9.75

7.81

7.70

0.98208

12 25

9.84

9.67

0.98806

7 30

5.83

5.76

0.98501

9.80

7.85

7.73

0.98203

12 30

9.89

9.71

0.98800

7 35

5.87

5.80

0.98495

9.85

7.89

7.77

0.98197

12 35

9.93

9.75

0.98794

7 40

5.91

5.84

0.98488

9 90

7.93

7.81

0.98191

12 40

9.97

9.79

0.98788

7 45

5.95

5.88

0.98482

9.95

7.97

7.85

0.98185

12 45

10.01

9.83

0.98781

7 50

5.99

5.92

0.98476

10 00

8.02

7.89

0.98180

12 50

10.05

9.87

0.98775

7 55

6.03

5.96

0.98470

10.05

8.06

7.93

0.98174

12.55

10.09

9.91

0.98769

7 60

6.07

6.00

0.98463

10.10

8.10

7.97

0.98168

12 60

10.13

9.95

0.98763

7 65

6.11

6.04

0.98457

10.15

8.14

8.01

0.98162

12 65

10.17

9.99

0.98756

7 70

6.15

6.08

0.98452

10 20

8.18

8.05

0.98156

12 70

10.21

10.03

0.98750

7.75

6.19

6.12

0.98446

10 25

8.22

8.09

0.98150

12.75

10.25

10.07

0.98744

7 80

6.24

6.16

0.98441

10.30

8.26

8.13

0.98145

12.80

10.29

10.10

0.98738

7 85

6.28

6.20

0.98435

10 35

8.30

8.17

0.98139

12 85

10.33

10.14

0.98731

7 90

6.32

6.24

0.98428

10.40

8.34

8.21

0.98132

12 90

10.38

10.18

0.98725

7.95

6.36

6.28

0.98422

10.45

8.38

8.25

0.98127

12 95

10.42

10.22

0.98718

8 00

6.40

6.32

0.98416

10.50

8.42

8.29

0.98122

13 00

10.46

10.26

0.98712

8 05

6.44

6.36

0.98410

10 55

8.46

8.33

0.98116

13 05

10.50

10.30

0.98706

8 10

6.48

6.39

0.98404

10 60

8.50

8.37

0.98111

13 10

10.54

10.34

0.98700

8 15

6.52

6.43

0.98398

10.65

8.54

8.41

0.98105

13.15

10.58

10.38

0.98694

8 20

6.56

6.47

0.98391

10 70

8.58

8.45

0.98100

13 20

10.62

10.42

0.98688

8 25

6.60

6.51

0.98385

10.75

8.62

8.49

0.98094

13 25

10.66

10.46

0.98682

8 30

6.64

6.55

0.98379

10.80

8.66

8.52

0.98089

13 30

10.70

10.50

0.98676

8 35

6.68

6.59

0.9S373

10 85

8.70

8.56

0.98083

13 35

10.74

10.54

0.98670

8 40

6.72

6.63

0.98368

10.90

8.75

8.60

0.98077

13 40

10.78

10.58

0.98664

8 45

6.76

6.67

0.98362

10 95

8.79

8.64

0.98071

13 45

10.82

10.62

0.98658

8 50

6.80

6.71

0.98356

11 00

8.83

8.68

0.98066

13 50

10.86

10.66

0.98652

8 55

6.84

6.75

0.98350

11 05

8.87

8.72

0.98060

13 55

10.90

10.70

0.98646

8 60

6.88

6.79

0.98344

11.10

8.91

8.76

0.980.". J

13 60

10.95

10.74

0.98640

8 65

6.92

6.83

0.98338

11 15

8.95

8.80

0.98048

13 65

10.99

10 78

0.98633

8 70

6.96

6.87

0.98332

11.20

8.99

8.84

0.98043

13 70

11.03

10.81

0.98627

8 75

7.00

6.91

0.98326

11 25

9.03

8.88

0.98037

13 75

11 07

10.85

0.98620

8 80

7.04

6.95

0.98320

11 30

9.07

8.92

0.98031

13 80

11.11

10.89

0.9S0I1

8 85

7.08

6.99

0.98314

11.35

9.11

8.96

0.98025

13 85

11.16

10.93

0.98608

8 90

7.12

7.03

0.98308

11.40

9.15

9.00

0 98020

13 90

11.19

10.97

0.98602

8 95

7.16

7.07

0.98302

11.45

9.19

9.04

0.98014

13 95

11.23

11.01

0.98596

9 00

7.20

7.10

0.98296

11.59

9.23

9.08

0.98009

14 00

11.28

11 05

0.98590

9 05

7.24

7.11

0.98290

11.55

9.27

9.12

0 '.K003

14 05

11.32

11 09

0.98584

9 10

7.29

7.18

0.98285

11 60

9.32

9.16

0 97998

14 10

11.36

11.13

0.98578

9 15

7.33

7.2-2

0.98279

11.65

9.36

9.20

0 97992

14 15

11.40

11.17

0.98572

9 20

7.37

7.26

0.9827:;

11.70

9.40

9 24

0 97986

14 20

11.44

11.21

196

METHODS OF ANALYSIS

[Chap.

Table 16. — Alcohol Table. — Continued.

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

GRAVITY
20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

1 Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc

at 20° C.

weight

100 cc.

0.97980

14 25

11.48

11.25

0.97704

16 75

13.53

13.22

0.97438

19 25

15.59

15.20

0.97975

14 30

11.52

11.29

0.97699

16 80

13.57

13.26

0.97433

19 30

15.64

15.23

0.97969

14 35

11.56

11.33

0.97694

16 85

13.61

13.30

0.97428

19 35

15.68

15.27

0.97964

14 40

11.60

11.37

0.97689

16 90

13.66

L3.34

0.97423

19 40

15.72

15.31

0.97958

14 45

11.64

11.41

0.97683

16 95

13.70

13.38

0.97417

19 45

15.76

15.35

0.97953

14 50

11.68

11.44

0.97678

17 00

13.74

13.42

0.97412

19 50

15.80

15.39

0.97947

14 55

11.72

11.48

0.97672

17 05

13.78

13.46

0.97407

19 55

15.84

15.43

0.97942

14 60

11.77

11.52

0.97667

17 10

13.82

13.50

0.97402

19 60

15.88

15.47

0.97936

14 65

11.81

11.56

0.97661

17 15

13.86

13.54

0.97396

19 65

15.92

15.51

0.97930

14 70

11.85

11.60

0.97656

17 20

13.90

13.58

0.97391

19 70

15.97

15.55

0.97924

14.75

11.89

11.64

0.97650

17 25

13.94

13.62

0.97386

19 75

16.01

15.59

0.97919

14 80

11.93

11.68

0.97645

17 30

13.98

13.66

0.97381

19 80

16.05

15.63

0.97913

14 85

11.97

11.72

0.97639

17 35

1402

13.70

0.97375

19 85

16.09

15.67

0.97908

14 90

12.01

11.76

0.97634

17 40

14.07

13.74

0.97370

19 90

16.13

15.71

0.97902

14 95

12.05

11.80

0.97629

17.45

14-11

13.78

0.97364

19 95

16.17

15.75

0.97897

15 00

12.09

11.84

0.97624

17 50

14-15

13.81

0.97359

20 00

16.21

15.79

0.97891

15 05

12.18

11.88

0.97618

17 55

14-19

13.85

0.97354

20 05

16.25

15.83

0.97885

15 10

12.18

11.92

0.97613

17 60

14-23

13.89

0.97349

20 10

16.30

15.87

0.97879

15 15

12.22

11.96

0.97607

17 65

14-27

13.93

0.97344

20 15

16.34

15.91

0.97874

15 20

12.26

12.00

0.97602

17 70

14-31

13.97

0.97339

20 20

16.38

15.95

0.97868

15 25

12.30

12.04

0.97596

17.75

14-35

14.01

0.97333

20 25

16.42

15.99

0.97863

15 30

12.34

12.08

0.97591

17 80

14-40

14.05

0.97328

20 30

16.46

16.02

0.97857

15 35

12.38

12.12

0.97586

17 85

14-44

14.09

0.97322

20 35

16.50

16.06

0.97852

15 40

12.42

12.16

0.97581

17 90

14-48

14 13

097317

20 40

16.55

16.10

0.97846

15 45

12.46

12.20

0.97575

17 95

14-52

14.17

0. 97311

20 45

16.59

16.14

0.97841

15 50

12.50

12.23

0.97570

18 00

14.56

14.21

097306

20 50

16.63

16.18

0.97835

15 55

12.54

12.27

0.97564

18 05

14-60

14.25

097300

20 55

16.67

16.22

0.97830

15 60

12.59

12.31

0.97559

18 10

14-64

14.29

0 97295

20 60

16.71

16.26

0.97824

15 65

12.63

12 35

0.97553

18 15

14-68

14.33

0.97289

20 65

16.75

16.30

0.97819

15.70

12.67

12.39

0.97548

18 20

14-73

14.37

097284

20 70

16.80

16.34

0.97813

15 75

12.71

12.43

0.97542

18 25

14-77

14.41

0.97278

20 75

16.84

16.38

0.97808

15 80

12.75

12.47

0.97538

18 30

14-81

14.45

0.97273

20 80

16.88

16.42

0.97802

15 85

12.79

12.51

0.97532

18 35

14-85

14.49

0.97268

20 85

16.92

16.46

0.97797

15 90

12 88

12.55

0.97527

18 40

14-89

14.52

097263

20 90

16.96

16.50

0.97791

15.95

12.87

12.59

0.97522

18 45

14-93

14.56

097257

20 95

17.00

16.54

0.97786

16 00

12.92

12.63

0.97517

18 50

14-97

14.60

0.97252

21 00

17.04

16.58

0.97780

16 05

12.96

12.67

0.97512

18 55

15.01

14.64

097247

21 05

17.08

16.62

0.97775

16 10

13.00

12.71

0.97507

18 60

15.06

14.68

0.97242

21 10

17. IS

16.66

0.97769

16 15

13.04

12.75

0.97501

18 65

15.10

14 72

0.97237

21 15

17.17

16.70

0.97764

16 20

13.08

12.79

0.97496

18 70

15.14

14.76

0.97232

21 20

17.21

16.73

0.97758

16 25

18.12

12.83

0.97490

18 75

15.18

14.80

0.97227

21 25

17.25

16.77

0.97753

16 30

13.16

12.87

0.97485

18 80

15 22

11 M

0.97222

21 30

17.29

16.81

0.97747

16 35

13.20

12.91

0.97479

18 85

15.26

14.88

0.9721ti

21 35

t : . ss

16.85

0.97742

16 40

18.24

12.95

0.97474

18 90

15.30

14 92

0.97210

21 40

17.38

16.89

0.97737

16 45

13.28

12.99

0.97469

18 95

15.34

14.96

0.97204

21 45

17.42

16.93

0.97732

16 50

13.33

13.02

0.97464

19 00

15.39

15.00

0 97199

21 50

17.46

16.97

0.97726

16 55

13.37

13.06

0.97459

19 05

15.43

15.04

() 97193

21 55

17.50

17.01

0.977:21

16 60

13.41

13.10

0.97454

19 10

15.47

15.08

i) 97188

21 60

17.64

17 05

0.97715

16 65

13.45

13.14

0.97449

19 16

15.51

i:> L2

0.97183

21 65

17.58

17.09

0 '.»7710

16 70

13.49

13.18

0.97444

19 20

15.55

L5 L6

(I "7i7s

21 70

17 13

XVI]

WINES

197

5

Table 16.— Alcohol Table.

—Continued.

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

20° C.

Per cent

Per

Grams

20° C.

Per cent

Per

Grams

G R.WITT

20° C.

Per cent

1 Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

bv volumejcent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.97172

21 75

17.67

17.17

0.96896

24 25

19.75

19.14

0.96612

26.75

21.85

21.12

0.97167

21 80

17.71

17.21

0.96891

24 30

19.80

19.18

0.96606

26 80

21.90

21.16

0.97161

21 85

17.75

17.25

0.96885

24 35

19.84

19.22

0.96600

26 85

21.94

21.20

0.97156

21 90

17.79

17.29

0.96880

24 40

19.88

19.26

0.96595

26 90

21.98

21.23

0.97150

21 95

17.83

17.33

0.96874

24.45

19.92

19.30

0.96589

26 95

22.02

21.27

0.97145

22 00

17.88

17.37

0.96869

24 50

19.96

19.34

0.96583

27 00

22.07

21.31

0.97139

22 05

17.92

17.41

0.96863

24 55

20.00

19.38

0.96577

27 05

22.11

21.35

0.97134

22 10

17.96

17.45

0.96857

24 60

20.05

19.42

0.96571

27.10

22.15

21.39

097128

22 15

18.00

17.49

0.96851

24.65

20.09

19.46

0.96565

27.15

22.19

21.43

0.97123

22 20

18.04

17.52

0.96846

24 70

20.13

19.50

0.96559

27.20

22.24

21 .47

0.97118

22 25

18.08

17.56

0.96840

24 75

20.17

19.54

0.96553

27 25

22.28

21.51

0.97113

22 30

18.13

17.60

0.96835

24 80

20.22

19.58

0.96548

27 30

22.32

21.55

0.97107

22 35

18.17

17.64

0.96829

24 85

20.26

19.62

0.96542

27.35

22.36

21.59

0.97102

22 40

18.21

17.68

0.96823

24 90

20.30

19.66

0.96536

27 40

22.40

21.63

0.97096

22 45

18.25

17.72

0.96817

24 95

20.34

19.70

0.96530

27.45

22.44

21.67

0.97091

22 50

18.29

17.76

0.96812

25 00

20.38

19.73

0.96525

27 50

22.49

21.71

0.97085

22 65

18.33

17.80

0.96806

25 05

20.42

19.77

0.96519

27 55

22.53

21.75

097080

22 60

18.38

17.84

0.96801

25 10

20.47

19.81

0.96513

27 60

22.57

21.79

0.97074

22 65

18.42

17.88

0.96795

25.15

20.51

19.85

0.96507

27.65

22.61

21.83

0.97069

22 70

18.46

17.92

0.96789

26 20

20.55

19.89

0.96501

27.70

22.66

21.87

0.97063

22 75

18.50

17.96

0.96783

25 25

20.59

19.93

0.96495

27.76

22.70

21.91

0.97058

22 80

18.54

18.00

0.96778

26 30

20.64

19.97

0.96489

27.80

22.74

21.94

0.97052

22 85

18.58

18.04

0.96772

25 35

20.68

20.01

0.96483

27 85

22.78

21.98

0.97047

22 90

18.63

18.08

0.96766

25 40

20.72

20.05

0.96477

27 90

22.83

22 02

0.97041

22 95

18.67

18.12

0.96760

25.45

20.76

20.09

0.96471

27 95

22.87

22.06

097036

23 00

18.71

18.16

0.96755

25 50

20.80

20.13

0.96465

28 00

22.91

22.10

0.97030

23 05

18.75

18.20

0.96749

25 55

20.84

20.17

0.96459

28 05

22.95

22.14

0.97025

23 10

18.79

18.24

0.96744

25 60

20.89

20.21

0.96454

28 10

23.00

22.18

0.97019

23 15

18.83

18.28

0.96738

25 65

20.93

20.25

0.96448

28 15

23.04

22 22

097013

23 20

18.88

18.31

0.96733

25 70

20.97

20.29

0.96442

28 20

23.08

22.26

0.97007

23 25

18.92

18.35

0.96727

25 75

21 .01

20.33

0.96436

28 25

23.12

22.30

0.97002

23 30

18.96

18.39

0.96722

25 80

21.06

20.37

0.96430

28 30

23.17

22.34

0.96996

23 35

19.00

18.43

0.96716

25 85

21.10

20.41

0.96424

28 35

88.21

22.38

0.96991

23 40

19.04

18.47

0.96710

25 90

21.14

20.44

0.96418

28 40

23.25

22 42

0.96985

23 45

19.08

18.51

0.96704

25 95

21.18

20.48

0.96412

28.45

88.29

22.46

0.96980

23 50

19.13

18.55

0.96699

26 00

21.22

20.52

0.96406

28 50

28.88

22.50

0.96974

23 55

19.17

18.59

0.96693

26 05

21.26

20.56

0.96400

28 55

23.37

22 54

096969

23 60

19.21

18.63

0.96687

26 10

21.31

20.60

0.96393

28 60

23.42

22.57

0.96963

23 65

19.25

18.67

0.961 is 1

26 15

21.35

20.64

0.96387

28 65

88 . 46

22.61

0.96958

23 70

19.29

18.71

0.96675

26 20

21.39

20.68

0.963S1

28 70

23.51

22.65

0.96952

23 76

19.33

18.75

0.96669

26 25

21.43

2(1 72

ii 96375

28 75

23.55

22 69

0.96947

23 80

19.38

18.79

0.96664

26 30

21.48

20.76

0.963C9

28 80

23.59

22 73

0.96941

23 85

19.42

18.83

0.96658

26 35

21.52

20.80

0.96363

28 85

28 68

22.77

0.96936

23 90

19.46

18.87

0.96(1."»::

26 40

21.56

20.84

o 96357

28 90

23.67

22 M

0.96930

23 95

19.50

18.91

0.96647

26 45

21.60

20.88

0.963.")1

28 95

23.71

0.96925

24 00

19.55

18 94

0 96641

26 50

SI. 64

2(1 92

(346

29 00

22 89

0.96919

24.05

19.59

18.98

ii 96635

26 55

20 96

840

29 05

- 93

0.96913

24 10

19.63

19 02

0 96680

26.60

21 . 73

21.00

1 ..:<

29 10

.'_• "7

0.96907

24 15

19.67

19 06

o 96624

26 65

21.04

328

29 15

2:; ni

0.9690

24.20

19.71

19.10

o 96618

26 70

21.08

II 9i..

29 20

23.05

198

.METHODS OF ANALYSIS

[Chap.

Table 16.— Alcohol Table.— Continued.

ALCOHOL

ALCOHOL

iXCOHOL

SPECIFIC

SPECIFIC

SPECIFIC

GRAVITY
20° C.

Per cent

Per

Grams

20° C.

Per cent

Per

Grams

J20°C.

Per cent

Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.96316

29.25

23.97

23.09

0.96005

31.75

26.10

25.06

0.95669

34.25

28.26

27.03

0.96310

29 30

24.01

23.13

0.95998

31 80

26.15

25.10

0.95662

34.30

28.30

27.07

0.96304

29 35

24-05

23.17

0.95992

31 85

26.19

25.14

0.95655

34 35

28.34

27.11

0.96297

29.40

24-10

23.21

0.95985

31.90

26.23

25.18

0.95648

34.40

28.39

27.15

0.96291

29.45

24-14

23.25

0.95979

31 95

26.27

25.22

0.95641

34 45

28.43

27.19

0. 9628o

29 50

24. 18

23.29

0.95972

32 00

26.32

25.26

0.95634

34 50

28.48

27.23

0.96279

29 55

24.22

23.33

0.95965

32.05

26.36

25.30

0.95627

34 56

28. 5i

27.27

0.96273

29 60

24.27

23.36

0.95958

32 10

26.41

25.34

0.95619

34 60

28.56

27.31

0.96267

29.65

24.31

23.40

0.95952

32 15

26.45

25.38

0.95612

34 65

28.60

27.35

0.96261

29 70

24.35

23.44

0.95945

32 20

26.49

25.42

0.95605

34.70

28.65

27.39

0.9625.5

29.75

24.39

23.48

0.95939

32 25

26.53

25.46

0.95598

34 76

28.69

27 A3

0.96248

29 80

24-44

23.52

0.95932

32 30

26.58

25.50

0.95591

34 80

28.74

21 Al

0.96242

29 85

24.48

23.56

0.95926

32.35

26.62

25.54

0.95584

34 85

28.78

27.51

0.96236

29 90

24.52

23.60

0.95920

32 40

26.66

25.58

0.95577

34 90

28.82

27.55

0.96230

29 95

24.56

23.64

9.95913

32.45

26.70

25.61

0.95570

34 95

28.86

27.59

0.96224

30 00

24. 61

23.68

0.95906

32 50

26.75

25.64

0.95563

35 00

28.91

27.63

0.96218

30 05

24.65

23.72

9.95900

32.55

26.79

25.68

0.95556

35.05

28.95

27.67

0.96211

30 10

24.69

23.76

0.95893

32 60

26.83

25.72

0.95.549

35 10

29.00

27.71

0.96205

30 15

24.73

23.80

0.95887

32 65

26.87

25.76

0.95542

35 15

29.04

27.75

0.96199

30.20

24.78

23.84

0.95880

32.70

26.92

25.80

0.95535

35 20

29.08

27.78

0.96193

30 25

24.82

23.88

0.95873

32.75

26.96

25.84

0.95528

35 25

29.12

27.82

0.96187

30 30

24.87

23.92

0.95866

32.80

27.01

25.89

0.95521

35 30

29.17

27.86

0.96181

30 36

24.91

23.96

0.95859

32 85

27.05

25.93

0.95513

35 35

29.21

27.90

0.96175

30 40

24.95

24.00

0.95852

32 90

27.09

25.97

0.95506

36 40

29.26

27.94

0.96169

30 45

24.99

24.04

0.95846

32.95

27.13

26.01

0.95499

35.45

29.30

27.98

0.96163
0.96157
0.96150
0.96144
0.96138

0.96132
0.96125
0.96119
0 96112
0.96106

0.96100
0.96094
0.96088
0.96082
0.96075

0.96069
0.96062
0.96056
0.96049
0.96043

0.96036
0.96030
0.96024
(i 96018
0.96011

30 50
30 55
30 60
30 65
30 70

30 75
30 80
30 85
30 90

30 95

31 00
31.05
31 10
31 15
31.20

31.25
31.30
31.36
31.40
31.45

31.50
31.55
31 60
31.65
31 70

25.04
25.08
25.12
25. J 6
25.21

25.25
25.30
25.34
25.38
25.42

25.46
25.50
25.55
25.59
25.63

25.67
25.72
25.76
25.81
25.85

25.89
25.93
25.98
26.02
26.06

24.08
24.12
24.15
24.19
24.23

24.27
24.31
24.35
24.39
24.43

24.47
24.51
24.55
24.59
24.63

24.67
24.71
24.75
24.79
24.83

24.86
24.90
24.94
24.98
25.02

0.9583S
0.95833
0.95826
0.95819
0.95812

0.95806
0.95799
0.95792
0.95785
0.95778

0.95771
0.95764
0.95757
0.95751
0.95745

0.95738
0.95731
0.95724
0.95717
0.95710

0.95703
0.95696
0.95689
0.95682
0.95675

33 00
33.05
33 10
33 15
33.20

33 25
33 30
33 35
33.40
33.45

33.50
33.55
33 60
33 65
33.70

33.75
33 80
33 85

33 90
33.95

34 00
34 05
34.10
34.15
34.20

27.18
27.22
27.27
27.31
27.35

27.39
27.44

27.48
27.52
27.56

27.61
27.65
27.70
27.74
27.78

87. 88

27.87
27.91
27.96
28.00

28.04
28.08
28.13

28.17

>S' > ->

26.05
26.09
26.13
26.17
26.21

26.25
26.29
26.33
26.36
26.40

26.44
26.48
26.52
26.56
26.60

26.64
26.68
26.72
26.76
26. SO

26.84
26.88
26.92
26.96
26.99

0.95492
0.95485
0 95478
0.9.5470
0.95463

0.95456
0.95449
0.95441
0.95434
0.95426

0.95419
0.95412
0.95405
0.95397
0.95390

0 95382

0.95375
0.95367
0.95360
0.95353

0.95346
0.95338
0.95331
0.96323

0.95315

35 50
35 66
35 60
35 65
35 70

35 75
35 80

35 85

36 90

35 95

36 00
36 05
36 10
36 15
36 20

36 25
36 30
36 36
36 40
36 45

36 60
36 56
36 60
36 66
36 70

29.34
29.38
29.43
29.47
29.52

29.56
29.61
29.65
29.69
29.73

29 78
99. 8i

29.87
29.91
29.95

29.99
30.04
30.09
30.13
30.17

SO. 22
SO 26
30.31
S0.S5
30.39

28.02
28.06
28.10
28.14
28.18

28.22

28.26
28.30
28.34
28.38

28.42
28 46

28.49
28.53
28.57

2S.61
28.65
28.69

28 ::

28.81

28. S9
28 93
28 97

XVI]

WINES

199

5

Table 16.— Alcohol Table.-

—Continued.

ALCOHOL

ALCOHOL

ALCOHOL

SPECIFIC

SPECIFIC

SPECIFIC

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY"

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 203 C.

weight

100 cc.

0.95308

36.75

30.43

29.01

0.94926

39.25

32.63

30.99

0.94519

41.75

34.86

32.96

0.95301

36.80

30.48

29.05

0.94918

39 30

32.68

31.02

0.94510

41.80

34-91

33.00

0.95294

36 85

80.52

29.09

0.94910

39.35

32.72

31.06

0.94502

41.85

34-95

33.04

0.95287

36 90

30.57

29.13

0.94901

39.40

32.77

31.10

0.94494

41.90

85.00

33.07

0.95279

36 95

30.61

29.17

0.94893

39.45

32.81

31.14

0.94486

41.95

35.04

33.11

0.95272

37.00

30.66

29.21

0.94885

39.50

32.86

31.18

0.94477

42.00

35.09

33.15

0.95264

37.06

30.70

29.25

0.94877

39.55

32.90

31.22

0.94469

42.05

35.13

33.19

0.95257

37.10

30.74

29.29

0.94869

39.60

32.95

31.26

0.94460

42.10

35.18

33.23

0.95249

37 15

30.78

29.33

0.94861

39 65

82.99

31.30

0.94452

42.15

35.22

33.27

0.95242

37 20

30.83

29.36

0.94853

39.70

33.04

31.34

0.94443

42.20

85.27

33.31

0.95234

37 25

80.87

29.40

0.94845

39 75

33.08

31.38

0.94435

42 25

35.81

33.35

0.95227

37 30

30.92

29.44

0.94837

39 80

38.13

31.42

0.94427

42 30

85.36

33.39

0.95219

37.35

30.96

29.48

0.94829

39 85

38.17

31.46

0.94419

42 35

35.40

33.43

0.95211

37.40

31.01

29.52

0.94821

39.90

83.22

31.50

0.94410

42.40

35.45

33.47

0.95203

37.45

31.05

29.56

0.94813

39.95

33.26

31.54

0.94402

42.45

35.49

33.51

0.95196

37 50

81.09

29.60

0.94805

40.00

88.80

31.57

0.94393

42 50

35.54

33.55

0.95188

37 55

31.13

29.64

0.94797

40.05

83.34

31.61

0.94385

42.55

35.58

33.59

0.95181

37.60

31.18

29.68

0.94789

40.10

83.39

31.65

0.94376

42 60

85.68

33.63

0.95173

37.65

31.22

29.72

0.94781

40 15

33.43

31.69

0.94368

42 65

35.67

33.67

0.95166

37.70

31.27

29.76

0.94773

40.20

33.48

31.73

0.94359

42.70

35.72

33.71

0.95158

37 75

81.31

29.80

0.94765

40.25

83.52

31.77

0.94351

42.75

35.76

33.75

0.95151

37.80

31.36

29.84

0.94757

40.30

88.57

31.81

0.94342

42.80

35.81

33.78

0.95143

37.85

31.40

29.88

0.94749

40.35

33.61

31.85

0.94334

42 85

85.85

33.82

0.95135

37 90

81.45

29.92

0.94741

40.40

83.66

31.89

0.94325

42 90

35.90

33.86

0.95127

37.95

31.49

29.96

0.94733

40.45

33.70

31.93

0.94317

42.95

85.94

33.90

0.95120

38 00

31.53

29.99

0.94725

40.50

88.75

31.97

0.94308

43 00

35.99

33.94

0.95112

38 05

81.57

30.03

0.94717

40 55

83.79

32.01

0.94300

43 05

86.03

33. S8

0.95104

38.10

81.62

30.07

0.94708

40 60

88.84

32.05

0.94291

42 10

86.08

34.02

0.95096

38 15

81.66

30.11

0.94700

40.65

33.88

32.09

0.94283

43.15

86.12

34.06

0.95089

38 20

81.71

30.15

0.94692

40.70

33.93

32.13

0.94274

43.20

86.17

34.10

0.95081

38 25

31.75

30.19

0.94684

40.75

33.97

32.17

0.94265

43 25

86.21

34.14

0.95074

38 30

31.80

30.23

0.94676

40 80

34-02

32.20

0.94256

43 30

86.26

34.18

0.95066

38 35

31.84

30.27

0.94668

40.86

84-06

32.24

0.94248

43 36

86.80

34.22

0.95058

38 40

31.89

30.31

0.94659

40 90

34.ll

32. 2S

0.94239

43.40

86.35

34.26

0.95050

38.45

31.98

30.35

0.94651

40.96

84.15

32.32

0.94231

43.45

86.89

34.30

0.95043

38 50

81.97

30.39

0.94643

41 00

34-19

32.36

0.94222

43 50

86.44

34.34

0.95035

38 55

82.01

30.43

0.94635

41 05

84.23

32.40

0.942] 1

43 55

86.48

34.38

0.95027

38 60

32.06

30.47

0.94627

41.10

34-28

32.44

0.94205

43 60

34.42

0.95019

38 65

32.10

30.51

0.94619

41.15

84-82

32.48

0.94197

43 65

36.57

34.46

0.95011

38 70

32.15

30.55

0.94610

41 20

34-37

32.52

0.94188

43 79

36.62

34.49

0.05003

38 75

82.19

30.59

0.94602

41.25

84-41

32.56

0.94179

43 75

36.66

34.53

0.94996

38 80

82.24

30.63

0.94594

41.30

34.46

32.60

0.94170

43 80

36.71

34.57

0.94988

38 85

82.28

30.67

0.94586

41.35

84.50

32.64

0.94161

43 85

86.75

34.61

0.94980

38 90

82.83

30.71

0.94577

41 40

84.55

32.68

(I 94152

43 90

86.80

34 65

0.94972

38.95

82.87

30.75

0.94569

41.45

34.59

32.72

0.94144

43 95

86.84

34.69

0.94964

39 00

82.42

30.79

0.94560

41.60

84-64

32.76

0.94135

44 00

86.89

34.73

0.94956

39 05

82.46

30.83

0.94552

41.55

,:■ 88

32.80

0.94126

44 06

86.94

■ 77

0.94949

39 10

32.51

30.87

0.94544

41 60

84 . 78

32.84

0 '.'1117

44 10

36.99

34.81

0.94941

39 15

82.55

30.91

0.94536

41 65

84.77

32.88

0.94108

44 15

34.85

0.94934

39 20

82.59

30.95

0.94527

41 70

84.82

32.92

0.94099

44 20

87.08

34.89

200

METHODS OF ANALYSIS

Chap.

5

Table 16.— Alcohol Table.-

—Continued.

ALCOHOL

ALCOHOL

ALCOHOL

SPECIFIC

SPECIFIC

SPECIFIC

GRAVITY
20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

ORAVIT y

20° c.

Per cent

1 Per

Grams

4°

by volume

r-ent by

Der

4°

by volume

cent by

per

4°

by volume

pent by!

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc

at 20° C.

weight |

100 cc

0.94091

44 25

37.12

34.93

0.93638

46 75

39.41

36.90

0.93164

49.25

41.72

38.87

0.94082

44 30

37.17

34.97

0.93629

46 80

39.46

36.94

0.93155

49 30

41.77

38.91

0.94073

44 35

37.21

35.01

0.93019

46 85

39.50

36.98

0.93145

49 35

41.82

38.95

0.94064

44 40

37.26

35.05

0.93610

46 90

39.55

37.02

0.93136

49 40

41.87

38.99

0.94055

44.45

37.30

35.09

0.93600

46 95

39.59

37.06

0.93126

49.45

41.91

39.03

0.94046

44 50

37.35

35.13

0.93591

47 00

39.64

37.10

0.93116

49 50

41.96

39.07

0.94037

44.55

37.39

35.17

0.93582

47 05

39.68

37 . 14

0.93106

49 55

42.01

39.11

0.94028

44 60

37. U

35.20

0.93573

47.10

39.73

37.18

0.93096

49 60

42.06

39.15

0 94020

44.65

3748

35 24

0.93563

47.15

39.77

37.22

0.93086

49 65

42.10

39.19

0.94011

44 70

37.53

35.28

0.93554

47.20

39.82

37.26

0.93076

49 70

42.15

39.23

0.94002

44.75

37.57

35.32

0.93545

47.25

39.87

37.30

0.93066

49 75

42.19

39 27

0.93993

44 80

37.62

35.36

0.93536

47 30

39.92

37.34

0.93056

49 80

42.24

39.31

0.93984

44 85

37.66

35.40

0.93526

47 35

39.96

37.38

0.93046

49 85

42.29

39.35

0.93975

44 90

37.71

35.44

0.93517

47.40

40.01

37.42

0.93036

49 90

42 . 34

39.39

0.93966

44 95

37.75

35.48

0.93507

47 45

40.05

37.46

0.93026

49 95

42.38

39.43

0.93957

45 00

37.80

35.52

0.93498

47 50

40.10

37.49

0.93017

50 00

42.43

39 47

0.93948

45 05

37.85

35.56

0.93488

47 55

40.14

37.53

0.93007

50 05

42.47

39.51

0.93939

45 10

37.90

35.60

0.93479

47 60

40.19

37.57

0.92997

50 10

42 . 62

39.55

0.93931

45 15

37.94

35.64

0.93470

47.65

40.24

37.61

0.92987

50 15

42.57

39.59

0.93922

45 20

37.99

35.68

0.93461

47 70

40.29

37.65

0.92977

50 20

42.62

39.63

0.93912

45 25

38.03

35.72

0.93451

47.75

40.33

37.69

0.92967

50 25

42.66

39.67

0.93903

45 30

38.08

35.76

0.93442

47 80

40.38

37.73

0.92957

50 30

42.71

39.70

0.93894

45 35

38.12

35.80

0.93432

47 85

40.42

37.77

0.92947

50 35

42.76

39.74

0 93885

45.40

38.17

35.84

0.93423

47.90

40.47

37.81

0.92938

50 40

42.81

39.78

0.93876

45.45

38.21

35.88

0.93413

47.95

40.51

37.85

0.92928

50 45

42.85

39.82

0.93867

45 50

38.26

35.92

0.93404

48 00

40.56

37.89

0.92918

50 50

42.90

39.86

0.93858

45 55

38.30

35.96

0.93394

48 05

40.61

37.93

0.92908

50 55

42.94

39.90

0 93849

45 60

38.35

35.99

0.93385

48 10

40.66

37.97

0.92898

50 60

39.94

0.93840

45 65

38.39

36.03

0.93375

48 15

40.70

38.01

0.92888

50 65

4304

39.98

0.93831

45 70

38.44

36.07

0.93366

48 20

40.75

38.05

0.92879

50 70

43.09

40.02

0 93822

45 75

38.49

36.11

0.93356

48 25

40.79

38.09

0.92869

50 75

43.13

40.06

0.93^13

45 80

38.54

36.15

0.93347

48 30

40.84

38.13

0.92859

50 80

43.18

40.10

0.93803

45 85

38.58

36.19

0.93337

48 35

40.89

38.17

0.92849

50 85

40.14

0.93794

45 90

38.63

36.23

0.93328

48 40

40.94

38.21

0.92839

50 90

40.18

0.93785

45 95

38.67

36.27

0.93318

48 45

40.98

38.25

0.92829

50 95

40.22

0.93776

46 00

38.72

36.31

0.93308

48 50

41.03

38.29

0.92818

51 00

40.26

0.93767

46 05

38.76

36.35

0.93298

48 55

41.07

38.33

0.9280S

51 05

43.42

40.30

0.93758

46 10

38.81

36.39

0.932S9

48 60

41.12

38.36

0.927ns

51 10

43.47

40.34

0 93749

46.15

38.85

36.43

0.93279

48 65

41.16

38.40

0.92788

51 15

43.51

40.38

0.93740

46 20

38.90

36.47

0.93270

48 70

41.21

38.44

0.9277s

51 20

43.56

0.93730

46 25

38.95

36.51

0.93260

48 75

41.26

:n is

0.9- :

51 25

43.60

40 46

0.93721

46 30

39.00

36.55

0.93251

48 80

41.31

38.52

0.92759

51 30

43.65

40.49

0.93712

46 35

39.04

36.59

0.93241

48 85

41.35

38.56

0.9271:'

51 35

40.53

0.93703

46 40

39.09

36. 63

0.93232

48 90

41-40

38.60

0.92739

51 40

'

1

0.936" 3

46 45

39.13

36.67

0.93222

48 95

41.44

38.64

0.92729

51 45

43.79

40.61

0.936S4

46 50

39.18

36.70

0.93

49 00

41-49

38.68

0.92719

51 50

40.65

0.93675

48 55

39.22

36.74

0.93

49 05

41.54

38 7-'

0.927

51.55

0 . 03666

46.60

39.27

13194

49 10

41.59

38 7"

0.9

51 60

0.93656

46 65

0.93

49.15

0.9

51 65

■

40 77

0.93647

16 70

39.38

36. S6

0.93171

49 20

41. 6S

0.9.

51 70

44 03

Id si

XVI]

WINES

201

Table 16.— Alcohol Table.— Continued.

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

SPECIFIC

ALCOHOL

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

1 Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volumelcent bv

per

at 20° C.

weight

100 cc.

at 20° C

weight

100 cc.

at 20° C.

weight

100 cc.

0.92668

51 75

44-08

40.85

0.92157

54 25

46.46

42.82

0.91629

56.75

48.89

44.80

0.92658

51 80

44-13

40.89

0.92147

54 30

46.51

42.86

0.91618

56 80

48.94

44.83

0.92648

51 85

44-17

40.93

0.92137

54 35

46.56

42.90

0.91608

56 85

48.98

44.87

0.92637

51 90

44.22

40.97

0.92126

54.40

46.61

42.94

0.91597

56 90

49.03

44.91

0.92627

51.95

44-26

41.01

0.92116

54.45

46.66

42.98

0.91586

56 95

49.08

44.95

0.92617

52 00

44-31

41.05

0.92105

54 50

46.71

43.02

0.91575

57 00

49.13

44.99

0.92607

52 05

44-36

41.09

0.92095

54 55

46.75

43.06

0.91565

57 05

49.18

45.03

0.92597

52 10

44-41

41.13

0.92084

54 60

46.80

43.10

0.91554

57 10

49.23

45.07

0.92587

52 15

44-46

41.17

0.92074

54 65

46.85

43.14

0.91543

57.15

49.28

45.11

0.92577

52 20

44-51

41.20

0.92063

54 70

46.90

43.18

0.91532

57 20

49.33

45.15

0.92567

52 25

44-55

41.24

0.92053

54 75

46.94

43.22

0.91521

67 25

49.38

45.19

0.92557

52 30

44-60

41.28

0.92042

54 80

46.99

43.26

0.91510

57 30

49.43

45.23

0.92547

52 35

44-65

41.32

0.92032

54 85

47.04

43.30

0.91500

57 35

49.47

45.27

0.92537

52 40

44-70

41.36

0.92021

54 90

47 .09

43.34

0.91489

57 40

49.52

45.31

0.92527

52 45

44-74

41.40

0.92011

54 95

47-14

43.38

0.91478

57 45

49.57

45.35

0.92516

52 50

44-79

41.44

0.92000

55 00

47 .19

43.42

0.91467

57 50

49.62

45.39

0.92506

52 55

44-84

41.48

0.91990

55 05

47M

43.46

0.91457

57 55

49.67

45.43

0.92496

52 60

44-89

41.52

0.91979

55 10

47.29

43.49

0.91446

57 60

49.72

45.47

0.92486

52 65

44-93

41.56

0.91969

55 15

47.33

43.53

0.91435

57 65

49.77

45.51

0.92476

52 70

44-98

41.60

0.91958

55 20

47.38

43.57

0.91424

57.70

49.82

45.55

0.92466

52 75

45.03

41.64

0.91948

55 25

47.43

43.61

0.91414

57 75

49.87

45.59

0.92455

52 80

45.08

41.68

0.91937

55.30

47.48

43.65

0.91403

57 80

49.92

45.63

0 . 92445

52 85

45.12

41.72

0.91927

55 35

47.53

43.69

0.91392

67.85

49.96

45.67

0.92434

52 90

45.17

41.76

0.91916

65 40

47.58

43.73

0.91381

57 90

50.01

45.70

0.92424

52 95

45.22

41.80

0.91906

55 45

47 .62

43.77

0.91370

57.95

50. OS

45.74

0.92414

53 00

45.27

41.83

0.91895

65 50

47.67

43.81

0.91359

58 00

50.11

45.78

0.92404

53 05

45.31

41.87

0.91885

55 55

47.72

43.85

0.91348

58 05

50.16

45.82

0.92394

53 10

45.36

41.91

0.91874

55 60

47.77

43.89

0.91337

68 10

50.21

45.86

0.92384

53 15

45.41

41.95

0.91864

55 65

47 .82

43.93

0.91326

58 15

50 8 ■

4590

0.92373

53 20

45.46

41.99

0.91853

65 70

47 .87

43.97

0.91315

58 20

50.31

45.94

0.92363

53 25

45.51

42.03

0.91842

65 75

47 .91

44.01

0.91304

58 25

50.36

45.98

0.92353

53 30

45.56

42.07

0.91831

55 80

47 .96

44.04

0.91293

58 30

50.41

46.02

0.92343

53 35 '

45.60

42.11

0.91821

55 85

48.01

44.08

0.91282

58 35

50.46

46.06

0.92332

53 40

45.65

42 15

0.91810

65 90

48.06

44.12

0.91271

58 40

50.51

46.10

0.92322

53 45

45.70

42.19

0.91800

55 95

48.11

44.16

0.91261

68 45

50.55

46.14

0.92312

53 50

45.75

42.23

0.91789

56 00

48.16

44.20

0.91250

58 50

50.60

46.17

0.92302

53 55

45.79

42.27

0.91779

56 05

48.20

44.24

0.91239

68 55

50.65

46 21

0.921" 11

53 60

45.84

42.31

0.91768

56 10

48.25

44.28

0.9 12_'s

58 60

50.70

46 25

0.92281

53 65

45.89

42.35

0.91758

56 15

48.30

■11 32

0.91217

58 65

50.75

46 29

0.92271

63 70

45.94

42.39

0.91747

56 20

48.35

44.36

0.91206

68 70

50.80

46.33

0 92261

63 75

45.98

42.43

0.91736

56 25

48.40

44.40

0.91194

68 75

50.85

46.37

0.92250

53 80

46.03

42.47

0.91725

56 30

48.45

■11 11

0.91183

58 80

50.90

Hi 11

0.92240

53 85

46.08

42.51

0.91715

56 35

48.50

11 is

0.91171

58 85

50.95

46.45

0.92230

53 90

46.13

42.55

11 '.'1704

56 40

48.55

11 52

0.911i;n

58 90

51.00

46.49

0.92220

53 95

46.18

42.59

0.91694

56 45

48.59

11 56

0.91149

58 95

51.05

16 5:;

0.92209

54 00

46.23

42.62

0.916s:;

56 50

48.64

44.60

0 91138

59 00

51.10

46.57

0.92199

54 05

46.27

42.66

11 91672

66 55

48.69

■11 ill

0 "1127

59 05

51.15

46 61

0 92188

54 10

46.32

42 70

166]

56 60

0 91116

59 10

46 65

0 02178

54 15

46.36

12 71

0 91650

56 65

48.79

11 72

0 91104

59 15

Hi 69

0 92167

54 20

46.41

1 5:78

11 911

56 70

48.84

1! 76

0 91

59 20

51.30

202

METHODS OF ANALYSIS

[Chap.

5

Table 16.— Alcohol Table.-

—Continued.

ALCOHOL

ALCOHOL

ALCOHOL

SPECIFIC

specific

SPECIFIC

GRAVITY

20° C.

Per cent

Per

Grams

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

! Per

Grama

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volum<

i cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.91082

59 25

51.85

46.77

0.90520

61.75

53.85

48.74

0.89942

64 25

56.89

50.72

0.91071

59 30

51.40

46.81

0.90509

61.80

53.90

48.78

0.89930

64 30

56.44

50.76

0.91060

59 35

51.45

46.85

0.90497

61 85

53.95

48.82

0.89918

64 35

56.49

50.80

0.91049

59 40

51.50

46.89

0.90486

61.90

54.00

48.86

0.89907

64 40

56.54

.50. 83

0.91038

59 45

51.55

46.93

0.90474

61.95

54.05

48.90

0.89895

64 45

56.59

50.87

0.91027

59 50

51.60

46.97

0.90463

62 00

54.10

48.94

0.89884

64 50

56.64

50.91

0.91016

59 55

51.65

47.01

0.90451

62 05

54.15

48.98

0.89872

64 55

56.70

50.95

0.91005

59 60

51.70

47.05

0.90440

62 10

54-20

49.02

0.89861

64 60

56.75

50.99

0.90993

59 65

51.74

47.09

0.90428

62.15

54.25

49.06

0.89849

64 65

56.80

51.03

0.90982

59 70

51.79

47.12

0.90417

62.20

54.30

49.10

0.89837

64.70

56.85

51.07

0.90971

59 75

51.84

47.16

0.90406

62 25

54.35

49.14

0.89825

64.75

56.90

51.11

0.90960

59 80

51.89

47.20

0.90395

62 30

54-40

49.18

0.89814

64 80

56.95

51.15

0.90949

59 85

51.94

47.24

0.90383

62.35

54.45

49.22

0.89802

64 85

57.00

51.19

0.90938

59 90

51.99

47.28

0.90372

62 40

54.50

49.25

0.89791

64 90

57.05

51.23

0.90926

59 95

52.04

47.32

0.90360

62.45

54.55

49.29

0.89779

64 95

57.11

51.27

0.90915

60 00

52.09

47.36

0.90349

62 50

5 4. 60

49.33

0.89767

65 00

57.16

51.31

0.90904

60 05

52.14

47.40

0.90337

62 55

54.66

49.37

0.89755

65 05

57.21

51.35

0.90893

60 10

52.19

47.44

0.90326

62 60

54.71

49.41

0.89744

65 10

57.26

51.39

0.90882

60 15

52.24

47.48

0.90314

62 65

54.76

49.45

0.89732

65 15

57.81

51.43

0.90871

60 20

52.29

47.52

0.90302

62 70

54. 81

49.49

0.89720

65 20

57.36

51.47

0.90859

60 25

52.34

47.56

0.90290

62 75

54.86

49.53

0.89708

65 25

57.41

51.51

0.90848

60 30

52.89

47.60

0.90279

62 80

54.91

49.57

0.89696

65 30

57.46

51.55

0.90837

60 35

52.44

47.64

0.90267

62 85

54.96

49.61

0.89684

65 35

57.52

51.59

0.90826

60 40

52.49

47.68

0.90256

62 90

55.01

49.65

0.89672

65 40

57.57

51.63

0.90814

60 45

52.54

47.72

0.90244

62 95

55.06

49.69

0.89660

65 45

57.62

51.67

0.90803

60 50

52.59

47.76

0.90233

63 00

55.11

49.73

0.89649

65 50

57.67

51.71

0.90792

60 55

52.64

47.80

0.90221

63 05

55.16

49.77

0.89637

65 55

57.7?

51.75

0.90781

60 60

52.69

47.84

0.90210

63 10

55.21

49.81

0.89626

65 60

57.77

51.78

0.90769

60 65

52.74

47.88

0.90198

63.15

55.26

49.85

0.89614

65 65

57.83

51.82

0.90758

60 70

52.79

47.91

0.90187

63 20

55.31

49.89

0.89602

65 70

57.88

51.86

0.90747

60 75

52.84

47.95

0.90175

63 25

55.37

49.93

0.89590

65 75

57.93

51.90

0.90736

60 80

52.89

47.99

0.90163

63 30

55.42

49.97

0.89578

65 80

57.98

51.94

0.90724

60 85

52.94

48.03

0.90151

63 35

55.47

50.01

0.89566

65 85

58.04

51.98

0.90713

60 90

52.99

48.07

0.90140

63.40

55.52

50.04

0.89554

65 90

58.09

52.02

0.90701

60 95

53.04

48.11

0.90128

63 45

55.57

50.08

0.89542

65 95

58.14

52.06

0.90690

61 00

58.09

48.15

0.90117

63 50

55.62

50.12

0.89531

66 00

58.19

52.10

0.90678

61 05

53.14

48.19

0.90105

63 55

55.67

50.16

0.89519

66 05

58.24

52.14

0.90667

61 10

53.19

48.23

0.90094

63 60

55.72

50.20

0.89507

66 10

58.29

52.18

0.90656

61.15

53.24

48.27

0.90082

63 65

55.77

50.24

0.89495

66 15

68 16

52.22

0.90645

61 20

53.29

48.31

0.90070

63 70

55.82

50.28

0.89483

66 20

58.40

52.26

0.90633

61 25

53.34

48.35

0.90059

63 75

55.88

50.32

0.89471

66 25

58.45

52.30

0.90622

61.30

53.89

48.39

0.90048

63 80

55.93

50.36

0.89459

66 30

58.50

52.33

0.90610

61 35

58.44

48.43

0.90036

63.85

55.98

50.40

0.89447

66 35

58.55

52 "

0.90599

61 40

53.49

48.47

0.90025

63 90

56.03

50.44

0.89435

66 40

58.60

52.41

0.90588

61.45

53.55

48.51

0.90013

63.95

56.08

50. 4S

0.89423

66.46

5S.66

52.45

0.90577

61 50

53.60

48.55

0.90001

64 00

56.18

50.52

0.89411

66 50

58.71

52.49

0.90565

61 55

58.65

48.59

0.89989

64 05

56.18

50.56

0.89399

66 55

58 76

52 53

0.90554

61.60

58.70

48.62

0.89978

64 10

56.88

50.60

0.89387

66 60

5S.81

52.57

0.90543

61.65

58.75

48.66

0.89966

64.15

56 99

50.64

0.89375

66 65

58.87

52.61

0.90532

61 70

58.80

48.70

0.89954

64.20

56.84

50. 6S

(i 8 1

66 70

52 05

XVI]

WINES

203

Table 16.— Alcohol Table.— Continued.

SPECIFIC

GRAVITY

20° C.

4°

Per cent
by volume
at20°C.

Per

cent by
weight

Grams

per
100 cc.

0.89351
0.89339
0.89327
0.89315
0.89303

0.89291
0.89279
0.89267
0.89255
0.89243

0.89231
0.89219
0.89207
0.89195
0.89183

0.89171
0.89159
0.89147
0.89135
0.89122

0.89110
0.89098
0.89086
0.89074
0.89062

0.89050
0.89038
0.89026
0.89014
0.89001

0.88989
0.88977
0.88965
0.88952
0.88940

0.88928
0.88916

0.88904
0.88892
0.88879

0.88867
0.88854
0.SSS42
0.8SS30
0.88818

0.88805
0.88793
0.88781
0.88769
0.88756

66 75
66 80
66 85
66 90

66 95

67.00

67 05
67 10
67 15
67 20

67 25
67 30
67.35
67 40
67 45

67 50
67 55
67 60
67 65
67.70

67 75
67 80
67 85
67 90

67 95

68 00
68 05
68 10
68 15
68 20

68 25
68 30
68 35
68 40
68 45

68 50
68 65
68 60
68 65
68 70

68 75
68 80
68 85
68 90

68 95

69 00
69 05
69 10
69 15
69 20

58.97
59.02
59.07
59.12
59.18

59.23
59.28
59.83
59.39
69. U

59.49
59.54
59.60
59.65
59.70

59.75
59.81
59.86
59.91
59.96

60.02
60.07
60.12
60.17
60.28

60.28
60.33
60.38
60.44
60.49

60.54
60.59
60.65
60.70
60.75

60.80
60.86
60.91
60.96
61.01

61.07
61.12
61.17
61.22
61.28

61.38
61.89
61.44
61.49
61.54

52.69
52.73
52.77
52.81
52.85

52.89
52.93
52.97
53.01
53.04

53.08
53.12
53.16
53.20
53.24

53.28
53.32
53.36
53.40
53.44

53.48
53.52
53.56
53.60
53.64

53.68
53.72
53.75
53.79
53.83

53.87
53.91
53.95
53.99
54.03

54.07
54.11
54.15
54.19
54.23

54.27
54.31
54.35
54.39
54.43

54.47
54.51
54.54
54.58
54 62

Per cent
by volume
at 20° C.

Per

cent by
weight

Grams

per
100 cc.

0.88744

0.88732
0.88720
0.88707
0.88695

0.88682
0.88670
0.88658
0.88646
0.88633

0.88621
0.88608
0.88596
0.88583
0.88571

0.88558
0.88546
088533
0.88521
0.88508

0.88496
0.88484
0.88472
088459
0.88447

0.88434
0.88422
0.88409
0.88397
088384

0.88372
088359
0.88347
0.88334
0.88322

0.88309

0 KS297
0.88284
0.88272
0.88259

0.88246
0.88233
0.88221
0.88208
0.88196

i) ssis:-;
0 SS171
(I SS15S

I) SSI 15
0 NS132

69.25
69 30
69 35
69.40
69 45

69 50
69 55
69 60
69.65
69 70

69 75
69 80
69 85

69 90
69.95

70 00
70 05
70 10
70.15
70 20

70 25
70 30
70 35
70 40
70 45

70 50
70 55
70 60
70 65
70 70

70 75
70 80
70 85
70 90

70 95

71 00
71 05
71 10
71 15
71 20

71.25
71 30
71 35
71 40
71 45

71 60
71 55
71 60
71 65
71 70

61.60
61 . 65
61.70
61.75
61.81

61.86
61.92
61.97
62.02
62.07

62.18
62.18
62.24
62.29

62.39
62.45
62.50
62.56
62.61

62.66
62.71
62.77
62.82
62.87

62.98
63.03
63.09
63.14

63.20
63.25
63.31
68.86
63.41

63.46
63.52
63.57
63.63
63.68

63.74
63.79
63.84
68 89
63.95

64.00
64.06
64.11
6417
64 -'-'

54.66
54.70
54.74
54.78
54.82

54.86
54.90
54.94
54.98
55.02

55.06
55.10
55.14

\LCOHOL

Per cent
by volume
at 20° C.

Per

cent by
weight

Grams

per
100 cc.

55.18

55.22

55.25

55.29

55.33

55.37

55.41

55.45

55.49

55.53

55.57

55.61

55.65

55.69

55.73

55.77

55.81

55.85

55.89

55.93

55.97

56.01

56.04

56.08

56.12

56.16

56.20

56.24

56.28

56.32

56.36

56.40

56 11

56.48

56.52

56.56

56.60

0.88120
0.88107
0.88094
0.88081
0.88069

0.88056
0.88044
0.88031
0.88018
0.88005

0.87993
0.87980
0.87967
0.87954
0.87942

0.87929
0.87916
0.87903
0.87891
0.87878

0.87865
0.87852
0.87839
0.87826
0.87813

0.87800
0.87788
0.87775
0.87762
0.87749

0.87737
0.87724
0.87711
0.87698
0.87685

0.87672
0.87659
0.87646
0.87633
0.87620

0.87607

0 S759-1
0.87581
0 S7.-,f,S
0.87555

0.87542
0 87529
0.87516
0.87504
0 87491

71 75
71 80
71 85

71 90
71.95

72 00
72 05
72.10
72 15
72 20

72 25
72 30
72 35
72 40
72 45

72 50
72 55
72 60
72 65
72.70

72 75
72 80
72 85
72 90

72 95

73 00
73 05
73 10
73 15
73 20

73 25
73 30
73 35
73 40
73 45

73 50
73 55
73 60
73 65
73 70

73.75
73 80
73 85
73 90

73 95

74 00
74 05
74 10
74.15
74 20

64-27
64.82
64.38
64.48
64.49

64.54

64.60
64.65
64.71
64-76

64-82
64.87
64-98
64.98
65.08

65.08
65.14
65.19
65.25
65.80

65.86
65.41
65.47
65.52
65.58

65.63
65.69
65.74
65.80
65.85

65.91
65.96
66.02
66.07
66.18

66.18
66.28
66.28
66.84
66.39

66.45
66.50
66.66
66.61
66.67

66.72
66 I
66.89

66.89
66.94

56.64
56.68
56.72
56.75
56.79

56.83
56.87
56.91
56.95
56.99

57.03
57.07
57.11
57.15
57.19

57.23
57.27
57.31
57.35
57.38

57.42
57.46
57.50
57.54
57.58

57.62
57.66
57.70
57.74
57.78

57.82
57.86
57.90
57.94
57.98

58.02
58.06
58.10
58.14
58.17

5S.21
58.25
58.29
58.33
58.37

58.41
58.45
58.49
58.53
58.57

204

METHODS OF ANALYSIS

[Chap.

5

Table 16.— Alcohol Table. -

-Continued.

ALCOHOL

ALCOHOL

LLCOHOL

SPECIFIC

SPECIFIC

SPECIFIC

GRAVITY

20° C.

Per cent

Per

Grams

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per 1

Grama

4°

by volume

cent by

per

4°

by volume[cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc.

at20°C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.87478

74.25

67.00

58.61

0.86818

76.75

69.78

60.58

0.86137

79 25

72.63

62.56

0.87465

74 30

67.05

58.65

0.86805

76 80

69.84

60.62

0.86124

79 30

72.68

62.60

0.87452

74 35

67.11

58.69

0.86791

76 85

69.90

60.66

0.86110

79 35

72.74

62.64

0.87439

74 40

67.16

58.73

0.86778

76 90

69.95

60.70

0.86096

79.40

72.80

62.67

0.87426

74.45

67.22

58.77

0.86764

76 95

70.01

60.74

0.86082

79 45

72.86

62.71

0.87413

74.50

67.27

58.81

0.86751

77 00

70.06

60.78

0.86069

79 50

72.91

62.75

0.87400

74.55

67.33

58.85

0.86737

77 05

70.12

60.82

0.86055

79 55

72.97

62.79

0.87387

74 60

67.38

58.89

0.86724

77 10

70.18

60.86

0.86041

79 60

73.03

62.83

0.87373

74 65

67. U

58.93

0.86710

77 15

70.24

60.90

0.86027

79 65

73.09

62.87

0.87360

74.70

67.49

58.97

0.86697

77 20

70.29

60.94

0.86013

79.70

73.14

62.91

0.87347

74.75

67.55

59.01

0.86684

77 25

70.35

60.98

0.85999

79 75

73.20

62.95

0.87334

74 80

67.61

59.04

0.86671

77 30

70.40

61.02

0.85984

79 80

73.26

62.99

0.87321

74 85

67.67

59.08

0.86657

77 35

70.46

61.06

0.85970

79 85

73.32

&3.03

0.87308

74 90

67.72

59.12

0.86644

77 40

70.51

61.10

0.85956

79 90

73.37

63.07

0.87295

74 95

67.78

59.16

0.86630

77.45

70.57

61.14

0.85942

79 95

73.43

63.11

0.87282

75 00

67.83

59.20

0.86617

77 50

70.63

61.18

0.85928

80 00

73.49

63.15

0.87269

75 05

67.89

59.24

0.86603

77.55

70.69

61.22

0.85914

80 05

73.55

63 . 19

0.87256

75 10

67.94

59.28

0.86589

77 60

70.74

61.25

0.85901

80 10

73.60

63.23

0.87243

75.15

68.00

59.32

0.86575

77 65

70.80

61.29

0.85887

80 15

73.66

63.27

0.87230

75 20

68.05

59.36

0.86562

77.70

70.85

61.33

0.85873

80 20

73.72

63.30

0.87217

75.25

68.11

59.40

0.86548

77.75

70.91

61.37

0.85859

80 25

73.78

63.34

0.87204

75.30

68.16

59.44

0.86535

77 80

70.97

61.41

0.85846

80 30

73.83

63.38

0.87190

75 35

68.22

59.48

0.86521

77 85

71.03

61.45

0.85832

80 35

73.89

63.42

0.87177

75 40

68.27

59.52

0.86508

77 90

71.08

61.49

0.85818

80 40

73.95

63.46

0.87164

75.45

68.33

59.56

0.86494

77 95

71.14

61.53

0.85804

80.45

74-01

63.50

0.87151

75 50

68.38

59.60

0.86480

78.00

71.19

61.57

0.85789

80 50

74-06

63.54

0.87138

75 55

68.44

59.64

0.86466

78 05

71.25

61.61

0.85775

80 55

74.12

63.58

0.87125

75.60

68.49

59.67

0.86453

78 10

71.31

61.65

0.85761

80 60

74-18

63.62

0.87111

75.65

68.55

59.71

0.86439

78.15

71.37

61.69

0.85747

80 65

74-24

63.66

0.87098

75.70

68.60

59.75

0.86426

78 20

71.42

61.73

0.85733

80 70

74-30

63.70

0.87084

75.75

68.66

59.79

0.86412

78 25

71.48

61.77

0.85719

80 75

74.36

&3.74

0.87071

75.80

68.72

59.83

0.86399

78 30

71.54

61.81

0.85705

80 80

74-42

63.78

0.87058

75 85

68.78

59.87

0.86385

78 35

71.60

61.85

0.85691

80 85

74-48

63.82

0.87045

75.90

68.83

59.91

0.86371

78 40

71.65

61.88

0.85677

80 90

74-53

63.86

0.87032

75 95

68.89

59.95

0.86357

78 45

71.71

61.92

0.85663

80 95

74-59

63.90

0.87019

76 00

68.94

59.99

0.86344

78 50

71.76

61.96

0.85648

81 00

74.65

63.94

0.87005

76 05

69.00

60.03

0.86330

78 55

71.82

62.00

0.85634

81 05

74.71

63.98

0.86992

76.10

69.05

60.07

0.86316

78 60

71.88

62.04

0.85620

81.10

74.77

64.02

0.86979

76 15

69.11

60.11

0.86302

78 65

71.94

62.08

0.85606

81.15

74 83

64.06

0.86966

76 20

69.16

60.15

0.862S9

78.70

71.99

62.12

0.85592

81 20

74.88

64.09

0.86952

76 25

69.22

60.19

0.86275

78 75

72.05

62.16

0.85578

81 25

74.94

64.13

0.86939

76 30

69.27

60.23

0.86261

78 80

72.11

62.20

0.85564

81 30

75.00

64.17

0.86925

76 35

69.33

60.27

0.86247

78 85

72.17

62 24

0.85550

81 35

75.06

64.21

0.86912

76.40

69.39

60.31

0.86234

78 90

72.22

62 28

0.85536

81 40

75.12

64 25

0.86898

76 45

69.45

60.35

0.86220

78 95

72.28

62.32

0.85522

81 45

75.18

64.29

0.86885

76 50

69.50

60.39

0.86206

79 00

72 ■:

62.36

0.85507

81 50

76 ::

64.33

0.86872

76 55

69.56

60.43

0.86192

79 05

72.4')

62.40

81 55

75.30

64.37

0.86859

76.60

69.61

60.47

0.86179

79 10

72.45

62.44

0 85478

81 60

75.35

64 41

0.86S45

76.65

69.67

60.51

0.86165

79 15

62 18

0.85464

81 65

75.41

64.45

0.86832

76 70

69.72

60.54

0.86151

79 20

72.57

62 52

0.S5450

81 70

75.47

64.49

XVI]

WINES

205

Table 16. — Alcohol Table.— Continued.

Ai.noHor,

ALCOHOL

ALCOHflL

SPECIFIC

SPECIFIC

SPECIFIC

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

4°

by volume

cent by

per

4°

by volume

cent by

per

4°

by volume cent by

per

at20°C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

0.85436

81 75

75.53

64.53

0.84713

84 25

78.50

66.50

0.83957

86 75

81.56

68.48

0.85422

81 80

75.59

64.57

0.84698

84 30

78.56

66.54

0.83942

86.80

81.62

68.52

0.85408

81 85

75.65

64.61

0.84683

84 35

78.62

66.58

0.83927

86.85

81.68

68.56

0.85393

81.90

75.71

64.65

0.84668

84.40

78.68

66.62

0.83912

86 90

81.75

68.60

0.85379

81 95

75.77

64.69

0.84654

84.45

78.74

66.66

0.83896

86 95

81.81

68.64

0.85364

82 00

75.82

64.73

0.84639

84.50

78.80

66.70

0.83881

87 00

81.87

68.68

0.85350

82 05

75.88

64.77

0.84624

84.55

78.86

66.74

0.83865

87 05

81.93

68.72

0.85336

82 10

75.94

64.81

0.84609

84.60

78.93

66.78

0.83850

87.10

81.99

68.76

0.85322

82 15

76.00

64.85

0.84594

84 65

78.99

66.82

0.83834

87.15

82.05

68.80

0.85307

82 20

76.06

64.88

0.84579

84.70

79.05

66.86

0.83818

87.20

82.12

68.84

0.85293

82 25

76.12

64.92

0.84564

84.75

79.11

66.90

0.83802

87 25

82.18

68.88

0.85279

82 30

76.18

64.96

0.84549

84.80

79.17

66.94

0.83787

87 30

82.24

68.91

0.85265

82.35

76.24

65.00

0.84534

84.85

79.23

66.98

0.83771

87.35

82.30

68.95

0.85250

82 40

76.30

65.04

0.84519

84 90

79.29

67.02

0.83756

87.40

82.37

68.99

0.85236

82 45

76.36

65.08

0.84504

84.95

79.35

67.06

0.83740

87.45

82.43

69.03

0.85222

82.50

76.41

65.12

0.84489

85 00

79.41

67.09

0.83725

87 50

82.49

69.07

0.85207

82 55

76.47

65.16

0.84474

85.05

79.47

67.13

0.83709

87 55

82.55

69.11

0.85192

82 60

76.53

65.20

0.84459

85.10

79.53

67.17

0.83694

87 60

82.62

69.15

0.85178

82.65

76.59

65.24

0.84444

85 15

79.59

67.21

0.83678

87 65

82.68

69.19

0.85164

82.70

76.65

65.28

0.84429

85 20

79.65

67.25

0.83663

87.70

82.74

69.23

0.85150

82 75

76.71

65.32

0.84414

85 25

79.71

67.29

0.83647

87 75

82.80

69.27

0.85135

82 80

76.77

65.36

0.84399

85 30

79.78

67.33

0.83632

87 80

82.87

69.30

0.85121

82.85

76.83

65.40

0.84384

85.35

79.84

67.37

0.83616

87 85

82.93

69.34

0.85106

82 90

76.89

65.44

0.84369

85 40

79.90

67.41

0.83601

87 90

82.99

69.38

0.85092

82 95

76.95

65.48

0.84354

85 45

79.96

67.45

0.83585

87.95

83.05

69.42

0.85077

83 00

77.01

65.51

0.84339

85 50

80.02

67.49

0.83569

88 00

83.12

69.46

0.85063

83 05

77.07

65.55

0.84323

85 55

80.08

67.53

0.83553

88 05

83.18

69.50

0.85049

83.10

77.13

65.59

0.84308

85 60

80.14

67.57

0.83537

88 10

83.25

69.54

0.85035

83 15

77.19

65.63

0.84293

85 65

80.20

67.61

0.83521

88 15

83.31

69.58

0.85020

83 20

77.24

65.67

0.84278

85 70

80.27

67.65

0.83505

88 20

83.37

69.62

0.85006

83 25

77.30

65.71

0.84263

85 75

80.33

67.69

0.83489

88 25

83.43

69.66

0.84991

83 30

77.36

65.75

0.84248

85 80

80.39

67.73

0.83473

88 30

83.50

69.70

0.84977

83 35

77.42

65.79

0.84233

85 85

80.45

67.77

0.83457

88 35

83.56

69.74

0.84962

83 40

77.48

65.83

0.84218

85 90

80.51

67.80

0.83442

88 40

83.63

69.78

0.84948

83 45

77.54

65.87

0.84203

85 95

80.57

67.84

0.83426

88.45

83.69

69.82

0.84933

83 50

77.60

65.91

0.84188

86 00

80.63

67.88

0.83410

88 50

83.75

69.86

0.84918

83 55

77.66

65.95

0.84172

86 05

80.69

67.92

0.83394

88.55

83.81

69.90

0.84903

83 60

77.72

65.99

0.84157

86 10

80.76

67.96

0.83379

88 60

83.88

69.94

0.84889

83 65

77.78

66.03

0.84141

86 15

80.82

68.00

0.83363

88 65

83.94

69.98

0.84874

83 70

77.84

66.07

0.84126

86 20

80.88

68.04

0.83347

88.70

84.00

70.01

0.84859

83 75

77.90

66.11

0.84110

86 25

80.94

68.08

0.83331

88 75

84.06

70.05

0.84844

83 80

77.96

66.15

0.84095

86 30

81.00

68.12

0.83315

88 80

84.13

70.09

0.84830

83 85

78.02

66.19

0.84080

86 35

81.06

68.16

0.83299

88 85

84.19

70.13

0.84815

83 90

78.08

66.23

0.84065

86 40

81.13

68.20

ii s:;_-s;;

88 90

84 96

70.17

0.84801

83 95

78.14

66.27

0.84049

86 45

81.19

68.24

0.83267

88 95

84.32

70.21

0.84786

84 00

78.20

66.30

0.84034

86 50

81.25

68.28

0.83251

89 00

84.39

70.25

0.84772

84 05

78.26

66.34

0.84018

86 55

81.31

68.32

0.83235

89 05

84.45

70.29

0.84757

84 10

78.32

66.38

0.84003

86.60

81.37

(is :;r,

0.83219

89 10

84-51

70.33

0.84742

84 15

78.38

66.42

0.83987

86 65

81.43

IIS III

0.83203

89 15

84 67

70.37

0.84727

84 20

78.44

<iii HI

0.83972

86 70

81.50

lis ||

0.83186

89 20

84.64

70.41

206

METHODS OF ANALYSIS

[Chap.

Table 16.— Alcohol Table. — Continued.

ALCOHOL

ALCOHOL

j

ILCOHOL

8PEWFIC

SPECIFIC

SPECIFIC

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

' 20° C.

Per cent

Per 1

Grams

4°

by volume

cent by

per

4°

by volume cent by

per

4°

by volume

cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc.

at 20° C.

weight |

100 cc.

0.83170

89 25

84.70

70.45

0.82332

91 75

87.96

72.42

0.81432

94 25

91.36

74.40

0.83154

89 30

84.77

70.49

0.82315

91 80

88.03

72.46

0.81413

94 30

91.43

74.44

0.83138

89 35

84.83

70.53

0.82298

91 85

88.09

72.50

0.81394

94 35

91.50

74.48

0.83121

89 40

84.90

70.57

0.82281

91 90

88.16

72.54

0.81375

94 40

91.57

74.52

0.83105

89.45

84-96

70.61

0.82263

91 95

88.22

72.58

0.81356

94 45

91.64

74.56

0.83089

89 60

85.03

70.65

0.82246

92 00

88.29

72.62

0.81337

94 50

91.71

74.59

0.83073

89 55

85.09

70.69

0.82229

92 05

8S.36

72.66

0.81318

94 55

91.78

74.63

0.83056

89 60

85.15

70.72

0.82212

92 10

88.43

72.70

0.81299

94 60

91.85

74.67

0.83040

89 65

85.21

70.76

0.82194

92 15

88.49

72.74

0.81280

94 65

91.92

74.71

0.83024

89.70

85.28

70.80

0.82177

92.20

88.56

72.78

0.81260

94 70

91.99

74.75

0.83008

89.75

85.34

70.84

0.82159

92 25

88.63

72.82

0.81241

94 75

92.06

74.79

0.82991

89.80

85.41

70.88

0.82141

92 30

88.70

72.86

0.81222

94 80

92.13

74.83

0.82975

89 85

85.47

70.92

0.82123

92 35

88.76

72.90

0.81202

94 85

92.20

74.87

0.82958

89 90

85.54

70.96

0.82106

92 40

88.83

72.94

0.81183

94 90

92.27

74.91

0.82942

89 95

85.60

71.00

0.82088

92 45

88.89

72.98

0.81163

94 95

92.34

74.95

0.82925

90 00

85.67

71.04

0.82071

92 50

88.96

73.02

0.81144

95 00

92.41

74.99

0.82909

90 05

85.73

71.08

0.82053

92 55

89.03

73.06

0.81124

95 05

92.48

75.03

0.82892

90 10

85.80

71.12

0.82035

92 60

89.10

73.09

0.81105

95 10

92.55

75.07

0.82876

90 15

85.86

71.16

0.82017

92 65

89.16

73.13

0.81086

95 15

92.63

75.11

0.82859

90 20

85.93

71.20

0.82000

92 70

89.23

73.17

0.81067

95 20

92.70

75.15

0.82843

90 25

85.99

71.24

0.81982

92 75

89.30

73.21

0.81047

95 25

92.77

75.19

0.82826

90 30

86.06

71.28

0.81964

92 80

89.37

73.25

0.81028

95 30

92.84

75.23

0.82810

90 35

86.12

71.32

0.81946

92 85

89.43

73.29

0.81008

95 35

92.91

75.27

0.82793

90 40

86.19

71.36

0.81929

92 90

89.50

73.33

0.80988

95 40

92.98

75.30

0.82776

90 45

86.25

71.40

0.81911

92 95

89.57

73.37

0.80968

95 45

93.05

75.34

0.82759

90 50

86.32

71.44

0.81893

93 00

89.64

73.41

0.80949

95 50

93.12

75.38

0.82742

90 55

86.38

71.48

0.81875

93 05

89.71

73.45

0.80929

95 55

93.20

75.42

0.82725

90 60

86.45

71.52

0.81856

93 10

89.78

73.49

0.80909

95.60

93.27

75.46

0.82708

90 65

86.51

71.56

0.81838

93 15

89.84

73.53

0.80889

95 65

93.34

75.50

0.82691

90 70

86.58

71.59

0.81821

93 20

89.91

73.57

0.80869

95 70

93.41

75.54

0.82674

90 75

86.64

71.63

0.81803

93 25

89.98

73.61

0.80849

95 75

93.48

75.58

0.82657

90 80

86.71

71.67

0.81784

93 30

90.05

73.65

0.80829

95 80

93.55

75.62

0.82640

90 85

86.77

71.71

0.81766

93 35

90.12

73.69

0.80809

95 85

93.63

75.66

0.82624

90 90

86.84

71.75

0.81748

93 40

90.19

73.72

0.80789

95 90

93.70

75.70

0.82607

90 95

86.90

71.79

0.81730

93 45

90.25

73.76

0.80769

95 95

93.77

75.74

0.82590

91 00

86.97

71.83

0.81711

93 50

90.32

73.80

0.80749

96 00

93.84

75 . 78

0.82573

91 05

87.03

71.87

0.81693

93 55

90.39

73.84

0.80729

96 05

93.92

7:. 82

0.82556

91 10

87.10

71.91

0.81675

93 60

90.46

73.88

0.80709

96 10

93.99

75.86

0.82539

91 15

87.17

71.95

0.81657

93 65

90.53

73.92

0.80689

96 15

9406

75.90

0.82522

91 20

87.24

71.99

0.81638

93 70

90.60

73.96

0.80668

96 20

9413

75.94

0.82505

91 25

87.30

72.03

0.81620

93 75

90.67

74.00

0.80648

96 25

94.21

75.98

0.82488

91 30

87.37

72.07

0.81601

93 80

90.74

74.04

0.80627

96 30

94 K

76.01

0.82470

91 35

87.43

72.11

0.81582

93 85

90.80

74.08

0.80607

96 35

94-35

76.05

0.82453

91 40

87.50

72.15

0.81563

93 90

90.87

71 12

0.S0586

96 40

76.09

0.82436

91 45

87.56

72.19

0.81545

93 95

90.94

74.16

0.80566

96 45

94.50

76.13

0.82419

91 50

87.63

72.23

0.81526

94 00

91.01

74 20

ii 80545

96 50

9457

76 17

0.82401

91 55

87.69

72.27

0.81507

94 05

91.08

71 24

0 80525

96 55

94.65

76 2]

0.82384

91 60

87.76

72.30

n si jxx

94 10

91.15

71 28

0.80504

96 60

76 25

0.82367

91 65

87.83

72.34

0.81469

94 15

91 SS

71 32

o 80483

96 65

94.79

0.82350

91 70

87.90

72.38

0.81450

94 20

91.29

71 36

0.80462

96 70

94.86

76.33

XVI]

WINES

207

Table 16.— Alcohol Table.— Concluded.

ALCOHOL

ALCOHOL

ALCOHOL

SPECIFIC

SPECIFIC

SPECIFIC

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

Per

Grams

GRAVITY

20° C.

Per cent

1 Per

Grams

4°

by volume

cent by

per

4°

by volume cent by

per

4°

by volume[cent by

per

at 20° C.

weight

100 cc.

at 20° C.

weight

100 cc

at 20° C.

weight

100 cc.

0.80442

96.75

94.94.

76.37

0.79900

98 00

96.82

77.36

0.79311

99 25

98.78

78.34

0.80421

96 80

95.01

76.41

0.79878

98 05

96.90

77.40

0.79286

99 30

98.86

78.38

0.80400

96 85

95.09

76.45

0.79855

98 10

96.97

77.43

0.79262

99 35

98.94

78.42

0.80379

96 90

95.16

76.49

0.79832

98.15

97.05

77.47

0.79237

99.40

99.02

78.46

0.80358

96 95

95.24

76.53

0.79809

98 20

97.12

77.51

0.79213

99 45

99.10

78.50

0.80337

97 00

95.31

76.57

0.79786

98 25

97.20

77.55

0.79188

99 50

99.18

78.54

0.80315

97.05

95.39

76.61

0.79763

98 30

97.28

77.59

0.79163

99 55

99.26

78.58

0.80294

97 10

95.46

76.65

0.79740

98 35

97.36

77.63

0.79138

99 60

99.34

78.62

0.80273

97 15

95.53

76.69

0.79717

98 40

97.43

77.67

0.79113

99.65

99.42

78.66

0.80252

97.20

95.60

76.72

0.79695

98 45

97.51

77.71

0.79088

99.70

99.51

78.70

0.80230

97.25

95.68

76.76

0.79672

98 50

97.59

77.75

0.79062

99 75

99.59

78.74

0.80208

97 30

95.75

76.80

0.79648

98 55

97.67

77.79

0.79037

99.80

99.67

78.78

0.80186

97 35

95.83

76.84

0.79625

98.60

97.75

77.83

0.79011

99 85

99.75

78.82

0.80164

97 40

95.91

76.88

0.79601

98 65

97.83

77.87

0.78986

99 90

99.83

78.86

0.80143

97.45

95.98

76.92

0.79577

98.70

97.90

77.91

0.78960

99 95

99.91

78.90

0.80122

97.50

96.05

76.96

0.79553

98 75

97.98

77.95

0.78934

100 00

100.00

78.93

0.80100

97.55

96.13

77.00

0.79529

98 80

98.06

77.99

0.80078

97 60

96.21

77.04

0.79505

98 85

98.14

78.03

0.80056

97.65

96.29

77.08

0.79481

98 90

98.22

78.07

0.80034

97.70

96.36

77.12

0.79457

98 95

98.30

78.11

0.80012

97 75

96.44

77.16

0.79432

99 00

98.38

78.14

0.79990

97 80

96.52

77.20

0.79408

99 05

98.46

78.18

0.79968

97 85

96.60

77.24

0.79384

99 10

98.54

78.22

0.79945

97 90

96.68

77.28

0.79360

99 15

98.62

78.26

0.79923

97 95

96.75

77.32

0.79335

99 20

98.70

78.30

208

METHODS OF ANALYSIS

[Chap.

Table 17 —Alcohol
For calculating the percentages of alcohol in mixtures of ethyl alcohol and

17.5

>c.

18°

C.

19

'C.

20*

C.

21° C.

SCALE
HEADING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

13.2

13.3

13.4

13.5

13.6

13.7

13.8

13.9

14.0

14.1

14.2

0 04

14.3

0 13

14.4

0 21

14.5

0 08

0.06

0 29

14.6

0 16

0.13

0 38

14.7

0 05

0.04

0 25

0.20

0 46

14.8

0.14

0.11

0.34

0.27

0 55

14.9

001

0.01

0 23

0.18

0 43

0.34

0 64

15.0

0 00

0.00

0 10

0.08

0 31

0.24

0 52

0.41

0 73

15.1

0 09

0.07

0 19

0.15

0 39

0.31

0 60

0.48

0 82

15.2

0 17

0.13

0 27

0.21

0 48

0.38

0 69

0.55

0 91

15.3

0 26

0.20

0 35

0.28

0 57

0.45

0.77

0.61

0.99

15.4

0.34

0.27

0.44

0.35

0.65

0.51

0 85

0.68

1 07

15.5

0 43

0.34

0.53

0.42

0 73

0.58

0.94

0.75

1.16

15.6

0.51

0.40

0 60

0.48

0 82

0.65

1.03

0.82

1.24

15.7

0.59

0.47

0 69

0.55

0 91

0.72

1.12

0.89

1.32

15.8

0 68

0.54

0.78

0.62

0 99

0.79

1.21

0.96

1 40

15.9

0.76

0.60

0.85

0.68

1.08

0.86

1 28

1.02

1.47

16.0

0.84

0.67

0 94

0.75

1.17

0.93

1.36

1.08

1 55

16.1

0 93

0.74

1.03

0.82

1.24

0.99

1.44

1.14

1 62

16.2

1 02

0.81

1 12

0.89

1.32

1.05

1 51

1.20

1 70

16.3

1 10

0.87

1 19

0.95

1 40

1.11

1 59

1.26

1.77

16.4

1.18

0.94

1 29

1.02

1.47

1.17

1 66

1.32

1 85

16.5

1.26

1.00

1 36

1.08

1 55

1.23

1.74

1.S8

1 92

16.6

1.34

1.06

1 43

1.13

1 62

1.29

1 81

1.44

2 00

16.7

1 41

1.12

1 50

1.19

1.70

1.35

1 89

1.50

2 07

16.8

1 49

1.18

1.57

1.25

1 77

1.41

1 96

1.56

2 15

16.9

1 56

1.24

1.65

1.31

1 85

1.47

2 04

1.62

2 22

17.0

1 63

1.30

1.72

1.37

1 92

1.53

2 11

1.68

2 30

17.1

1.70

1.35

1 80

1.43

1 99

1.58

2 19

1.74

2 37

17.2

1.77

1.41

1.87

1.49

2 06

1.64

2 26

1.80

2 45

17.3

1.85

1.47

1.94

1.54

2.14

1.70

2 34

1.86

2.62

17.4

1.92

1.53

2.01

1.60

2.21

1.76

2.41

1.92

2 59

17.5

2 00

1.59

2 09

1.66

2 29

1.82

2 49

1.98

2 66

17.6

2 07

1.65

2.16

1.72

2 36

1.88

2.56

■2.04

2.74

17.7

2.14

1.70

2.24

1.78

2 44

1.94

2 62

2.09

2 81

17.8

2.21

1.76

2.31

1.84

2 51

2.00

2 70

9.15

2 89

17.9

2.29

1.82

2.38

1.89

2.59

2.06

2.77

2.21

2 96

* Calculated and arranged by B. H. St. John from the data of Doroshevskii and Dvorzhanchik.*

A

vij

WINES

209

Table.

6

water from their Zeiss immersion ref

Tactometer reading

8* at 17.5°-25°C.

21°C.

22°

C.

23

'C.

24

'C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

vol ume

weight

volume

weight

volume

weight

volume

weight

0.00

0.00

13.2

0 09

0.07

13.3

0.18

0.14

13.4

0 05

0.04

0.26

0.21

13.5

0.14

0.11

0 35

0.28

13.6

0.01

b'.bi

0 23

0.18

0 44

0.85

13.7

0.10

0.08

0 31

0.25

0.53

0.42

13.8

0 19

0.15

0 40

0.32

0.62

0.49

ln>.9

0 08

0.06

0 28

0.22

0 49

0.39

0 70

0.56

14.0

0 16

0.13

0 36

0.29

0.58

0.46

0 79

0.63

14.1

0.03

0 24

0.19

0.45

0.36

0 67

0.53

0 88

0.70

14.2

0.10

0 33

0.26

0.54

0.43

0 75

0.60

0.97

0.77

14.3

0.17

0.41

0.33

0.63

0.50

0.84

0.67

1.06

0.85

14.4

0.23

0 50

0.40

0.72

0.57

0 93

0.74

1.15

0.92

14.5

0.30

0 59

0.47

0 80

0.64

1.02

0.81

1 24

0.99

14.6

0.37

0 68

0.54

0.89

0.71

1.11

0.88

1.32

1.05

14.7

o.U

0 77

0.61

0 98

0.78

1.19

0.95

1.40

1.11

14.8

0.51

0 85

0.68

1.07

0.85

1.28

1.02

1.47

1.17

14.9

0.58

0 94

0.75

1.16

0.92

1.36

1.08

1 55

1.28

15.0

0.65

1 03

0.82

1.24

0.99

1.44

1.14

1.63

1.29

15.1

0.72

1.12

0.89

1.32

1.05

1.51

1.20

1.71

1.36

15.2

0.79

1.21

0.96

1 40

1.11

1.59

1.26

1.79

1.42

15.3

0.85

1.29

1.02

1.47

1.17

1.66

1.82

1 86

1.48

15.4

0.92

1 36

1.08

1 55

1.23

1.74

1.38

1.94

1.64

15.5

0.99

1 44

1.15

1.62

1.29

1 82

1.44

2 01

1.60

15.6

1.05

1.52

1.21

1 70

1.35

1 90

1.51

2.09

1.66

15.7

1.11

1.60

1.27

1.77

1.41

1 97

1.57

2.17

1.72

15.8

1.17

1.67

1.33

1 85

1.47

2.05

1.63

2 25

1.79

15.9

1.23

1.75

1.39

1 92

1.53

2 12

1.69

2 33

1.85

16.0

1.29

1.82

1.45

2 00

1.59

2 20

1.75

2.40

1.91

16.1

1.35

1 90

1.51

2.08

1.65

2 27

1.81

2.48

1.97

16.2

1.41

1 97

1.57

2.16

1.72

2 35

1.87

2.65

2.08

16.3

1.47

2 05

1.63

2.24

1.78

2.43

1.98

2.62

2.09

16.4

1.53

2 12

1.69

2 31

1.84

2.50

1.99

2 70

2.15

16.5

1.59

2 20

1.75

2 39

1.90

2 57

2.05

2.77

2.21

16.6

1.65

2.27

1.81

2 46

1.96

2 65

2.11

2 85

2.27

16.7

1.71

2 35

1.87

2 53

2.02

2 72

2.17

2 92

2.33

16.8

1.77

2.43

1.93

2.61

2.08

2.80

2.28

2.99

2.88

16.9

1.83

2.50

1.99

2.69

2.14

2 87

2.29

3 06

2.44

17.0

1.89

2 57

2.05

2.76

2.20

2.95

2.85

3.14

2.50

17.1

1.95

2 65

2.11

2 82

2.25

3 02

2.41

3 21

2.66

17.2

2.01

2.72

2.17

2 90

2.81

3 10

2.47

3 29

2.62

17.3

2.07

2.79

2.23

2.97

2.37

3 17

2.58

3.36

2.68

17.4

2.12

2 86

2.28

3.04

2.43

3 25

2.59

3 43

2.74

17.5

2.18

2 94

2.34

3.12

2.49

3 32

2.65

3 51

2.80

17.6

2.24

3 01

2.40

3 20

2.55

3 39

2.70

3 58

2.86

17.7

2.30

3 09

2.46

3 27

2.61

3 46

2.76

3 66

.? 92

17.8

2.36

3 16

2.52

3 35

2.67

3 53

2.82

3 73

2.98

17.9

210

METHODS OF ANALYSIS

[Chap.

6

Table 17.-

-Alcohoi

17.5

°C.

18°

C.

19°

C.

20°

C.

21° C.

SCALE

READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

18.0

2 36

1.88

2 45

1.95

2 66

2.12

2 85

2.27

3 04

18.1

2 43

1.94

2 52

2.01

2.74

2.18

2 92

2.38

3.11

18.2

2 50

2.00

2.60

2.07

2 81

2.24

3 00

2.39

3 19

18.3

2.57

2.05

2 67

2.13

2 89

2.30

3.07

2.45

3 26

18.4

2.65

2.11

2.75

2.19

2.96

2.36

3 15

2.51

3 34

18.5

2.72

2.17

2 82

2.25

3 03

2.41

3 22

2.57

3 41

18.6

2.80

2.23

2 90

2.81

3 10

2.47

3 30

2.63

3 48

18.7

2 87

2.29

2.97

2.37

3 17

2.53

3 37

2.69

3 56

18.8

2.95

2.85

3 05

2.48

3 25

2.59

3 45

2.75

3 63

18.9

3.02

241

3 12

2.49

3 32

2.65

3 52

2.81

3 70

19.0

3 10

2.47

3 19

2.54

3.40

2.71

3 59

2.86

3 77

19.1

3 17

2.53

3 26

2.60

3.47

2.77

3.66

2.92

3 85

19.2

3 25

2.59

3 34

2.66

3 55

2.83

3 73

2.98

3 92

19.3

3 32

2.65

3.41

2.72

3 62

2.89

3 81

8.04

4 00

19.4

3 39

2.70

3.48

2.78

3 70

2.95

3 88

3.10

4 07

19.5

3 46

2.76

3 56

2.84

3 77

3.01

3 96

8.16

4 14

19.6

3.53

2.82

3 63

2.90

3 84

3.06

4 03

8.22

4 22

19.7

3 61

2.88

3.71

2.96

3.91

8.12

4.10

3.27

4 29

19.8

3 68

2.94

3 78

3.02

3.98

8.18

4 17

8.88

4 37

19.9

3.76

8.00

3 86

3.08

4 06

3.24

4 25

3.89

4 44

20.0

3 83

8.06

3 93

3.18

4.13

8.80

4 32

8. 45

4 52

20.1

3.90

8.12

4 00

8.19

4 20

8.35

4 39

8.51

4 59

20.2

3.97

8.17

4 07

3.25

4 27

8.41

4.47

3.57

4 66

20.3

4.04

3.23

4 14

3.31

4.34

8.47

4 54

8.63

4 74

20.4

4.12

3.29

4.22

3.37

4.42

3.53

4.61

3.68

4 82

20.5

4 19

8.85

4 29

3.43

4 49

8.59

4.68

8.74

4 89

20.6

4 26

S.41

4 36

8.49

4.56

8.65

4 75

8.80

4 96

20.7

4 33

3.46

4.43

8.54

4 63

8.70

4 83

8.86

5 03

20.8

4.41

8.52

4.51

8.60

4.70

3.76

4 90

8.92

5 10

20.9

4.48

3.58

4.58

3.66

4 78

8.82

4 97

8.98

6 17

21.0

4 56

8.64

4 65

8.72

4.85

3.88

5 04

4.08

5 24

21.1

4 63

3.70

4.73

8.78

4.92

8.94

5 11

4-09

6 31

21.2

4.70

3.76

4 80

3.84

4 99

8.99

5 19

4.15

5 39

21.3

4.77

8.81

4.87

8.89

5 06

4-05

5 26

4.21

5 46

21.4

4.84

8.87

4.94

8.95

5 14

4.11

6 33

4.26

5 53

21.5

4 92

3.93

5 01

4.01

5 21

4-17

5 40

4.32

5 60

21.6

4 99

3.99

5 09

4-07

5 28

4.22

5 47

4. 88

6 67

21.7

5.06

4.05

5.16

4.13

5 35

4.28

5 54

4-44

6 75

21.8

5 13

4.10

5 23

4.18

5 43

4-S4

5 61

4-49

5 82

21.9

5.20

4.16

5 30

4.24

5 50

4.40

6 69

4.55

5 89

22.0

6 27

4.22

5 37

4.80

5 57

4.45

5 76

4. 61

6 96

22.1

5.34

4.27

5.44

4.85

6.64

4.51

5 83

4.67

6 03

22.2

5.41

4-38

5.51

4-41

5.71

4.57

5 90

4-72

6 11

22.3

5.49

4.39

5.58

4.47

5.78

4.63

6 97

4.78

6 18

22.4

5.56

4.45

5 65

4.58

5.85

4. 68

6 05

4-84

6 25

22.5

5.63

4.51

5 72

4.58

6.92

4-74

6 12

4.90

6 32

22.6

5.70

4.56

5.80

4.64

6 00

4. 80

6.19

4.95

6 39

22.7

5.77

4.62

5 87

4.70

6.07

4.86

6 26

5.01

6 46

22.8

5 85

4.68

5.94

4.75

6.14

4.91

6 33

5.07

6 53

22 . 9

6 92

4.74

6.01

4. 81

6.21

4.97

6.40

5.13

6 60

XVI]

WINES

211

Table.— Continued.

21° C.

22°

C.

23°

C.

24°

C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

g.48

3 23

2.58

3 42

2.73

3 61

2.88

3 81

3.04

18.0

2.48

3 30

2.63

3 50

2.79

3.68

2.94

3 88

3.10

18.1

2.54

3 37

2.69

3 57

2.85

3 76

3.00

3 96

3.16

18.2

2.60

3 45

2.75

3 64

2.91

3 83

3.06

4 03

3.22

18.3

2.66

3 52

2.81

3 71

2.96

3 91

3.12

4.11

3.28

18.4

2.72

3.59

2.87

3 78

3.02

3 98

3.18

4.18

3.34

18.5

2.78

3 66

2.92

3 86

3.08

4 06

3.24

4.26

3.40

18.6

2.83

3 73

2.98

3 93

3.14

4 13

3.30

4 33

3.46

18.7

2.89

3 81

3.04

4 01

3.20

4.21

3.36

4.41

3.52

18.8

2.95

3.88

3.10

4.08

3.26

4 28

3.42

4.48

3.58

18.9

3.01

3.96

3.16

4.16

3.32

4.36

3.48

4.56

3.64

19.0

3.07

4.03

3.22

4 23

3.38

4.43

3.54

4 63

3.70

19.1

3.13

4.11

3.28

4.31

3. 44

4.51

3.60

4.70

3.76

19.2

3.19

4.18

3.34

4.38

3.50

4.58

3.66

4.78

3.82

19.3

3.25

4.26

3.40

4.46

3.56

4.65

3.72

4.85

3.88

19.4

3.31

4 33

3.46

4.53

3.62

4.73

3.78

4.93

3. 94

19.5

3.37

4.41

3.52

4.61

3.68

4.80

3.84

5.00

4.00

19.6

3.43

4.48

3.58

4.68

3.74

4.88

3.90

5 08

406

19.7

3.49

4.56

3.64

4.75

3.80

4.95

3.96

5.15

4.12

19.8

3.55

4 63

3.70

4.83

3.86

5.03

4-02

5 22

4.17

19.9

3.61

4.72

3.77

4.90

3.92

5.10

4. 08

5.29

4.23

20.0

3.67

4.79

3.83

4 98

3.98

5.17

4.13

5 36

4-29

20.1

3.73

4.87

3.89

5 05

4.04

5.24

4.19

5.44

4.35

20.2

3.79

4 94

3.95

5 13

4.10

5 31

4.25

5.51

4.41

20.3

3.85

5.01

4.01

5 20

4. 16

5 38

4.31

5.58

4-47

20.4

3.91

5 08

4.06

5 27

4.21

5 45

4.37

5 65

4.52

20.5

3.97

5.15

4.12

5 34

4.27

5 52

4-42

5 72

4.58

20.6

4.02

5 22

4. 18

5.41

4.33

5 60

4.48

5 80

4-64

20.7

4.08

5 29

4M

5.48

4.39

5 67

4-54

5.87

4.70

20.8

4.14

5.36

4.29

5 55

4.45

5 75

4. 60

5.95

4.76

20.9

4.20

5 44

4.35

5 62

4.50

5 82

4.66

6 02

4. 81

21.0

4.25

5.51

4.41

5.70

4.56

5 89

4.72

6 09

4.87

21.1

4.31

5 58

4.47

5.77

4.62

5 96

4.77

6 16

4.93

21.2

4.37

5 65

4.52

5.84

4.68

6 03

4. 83

6 23

4.99

21.3

4.43

5.72

4.58

5.91

4.73

6.11

4.89

6.30

5.05

21.4

4-48

5 80

4M

5 98

4.79

6 18

4.95

6 37

5.10

21.5

4.54

5.87

4.70

6 06

4.85

6.25

5.01

6.44

5.16

21.6

4. 60

5 94

4.75

6 13

4.91

6 32

5.06

6.52

5.22

21.7

4.66

6 01

4.81

6 20

4.97

6 39

5.12

6 59

5.28

21.8

4.71

6 08

4.87

6 27

5.02

6.47

5.18

6 66

5.34

21.9

4.77

6 15

4.93

6 34

5.08

6 54

5.24

6.73

5.39

22.0

4.83

6 22

4.98

6 42

5.14

6.61

5.29

6 80

5.45

22.1

4.89

6 29

5.04

6 49

5.20

6 68

5.35

6 87

5.51

22 . 2

4.95

6 36

5.10

6 56

5.25

6.75

5.41

6.94

5.57

22.3

5.00

6 43

5.15

6 63

5.31

6.82

5.47

7.01

5.62

22. \

5.06

6.50

5.21

6.70

5.37

6 89

7.08

5.68

22.5

5.11

6.57

5.27

6 77

5.43

6 96

5.58

7.16

5.74

22 . 6

5.17

6 64

5.33

6 84

5.48

7.03

5.64

7.23

5.80

22.7

5.23

6 71

5.38

6 91

5.54

7.10

5.70

7.31

5.86

22 . 8

5.29

6.78

5.44

6.99

5.60

7.17

5.75

7.38

5.91

22.9

212
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

' C.

18°

C.

19°

C.

20°

C

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

23.0

5 99

4.79

6 08

4.87

6 28

5.03

6.47

5.18

6 67

23.1

6.06

4.85

6.15

4.93

6 35

5.09

6 54

5.24

6 74

23.2

6.13

4.91

6 22

4.98

6 42

5.14

6 61

5.30

6 81

23.3

6.20

4.97

6 29

5.04

6.49

5.20

6 68

5.36

6 88

23.4

6 27

5.02

6 36

5.10

6 66

5.26

6 75

5.41

6 96

23.5

6 34

5.08

6 43

5.15

6.63

5.81

6 83

5 47

7 02

23.6

6 41

5.14

6 50

5.21

6 70

5.37

6 90

5.58

7 09

23.7

6 48

5.19

6 57

5.27

6 78

5.43

6 97

5.59

7 16

23.8

6 55

5.25

6 64

5.32

6 85

5.49

7 04

5.64

7 23

23.9

6 62

5.80

6.71

5.38

6 92

5.54

7 11

5.70

7 31

24.0

6 69

5.36

6 78

5.44

6 99

5.60

7 18

5.76

7 38

24.1

6 76

5.42

6 85

5.49

7.06

5.66

7 25

5.82

7 45

24.2

6 83

5.47

6 92

5.55

7.13

5.71

7 32

5.87

7 52

24.3

6 90

5.53

6 99

5.61

7 20

5.77

7 39

5.93

7.59

24.4

6 97

5.59

7.06

5.66

7.27

5.83

7.46

5.99

7 66

24.5

7.04

5.64

7.13

5.72

7.34

5.S9

7 53

6.04

7 73

24.6

7 11

5.70

7 20

5.78

7.41

5.94

7 60

6.10

7 80

24.7

7 18

5.76

7.27

5.83

7 48

6.00

7.67

6.15

7 86

24.8

7 25

5.81

7 35

5.89

7 55

6.06

7.74

6.21

7 93

24.9

7 32

5.87

7.42

5.95

7.62

6.11

7 81

6.26

8 00

25.0

7 39

5.98

7 49

6.01

7 68

6.16

7 88

6.82

8 06

25.1

7.46

5.98

7 56

6.06

7.75

6.22

7.94

6.37

8 13

25.2

7 63

6.04

7 63

6.12

7 82

6.27

8 01

6.43

8 20

25.3

7 59

6.09

7.69

6.17

7 89

6.33

8 07

6.48

8 27

25.4

7.66

6.15

7 76

6.23

7 95

6.88

8 14

6.54

8 34

25.5

7 73

6.20

7 83

6.28

8 02

6.44

8 21

6.59

8 41

25.6

7 80

6.26

7 90

6.34

8 09

6.49

8 28

6.65

8 48

25.7

7.87

6.31

7 96

6.39

8.16

6.55

8 35

6.70

8 55

25.8

7 94

6.37

8 03

6.44

8 22

6.60

8.42

6.76

8 62

25.9

8 00

6.42

8 10

6.50

8 29

6.66

8.48

6.81

8 69

26.0

8 07

6.48

8 16

6.55

8 36

6.71

8 55

6.87

8 76

26.1

8 14

6.53

8 23

6.61

8 43

6.77

8 62

6.92

8 82

26.2

8 21

6.59

8 30

6.66

8 50

6.82

8 69

6.98

8 89

26.3

8 27

6.64

8 37

6.72

8 57

6.88

8 75

7.03

8 96

26.4

8 34

6.70

8.44

6.78

8.63

6.93

8 82

7.09

9 03

26.5

8.41

6.75

8 50

6.83

8 70

6.99

8 89

7.15

9 10

26.6

8 48

6.81

8 57

6.S8

8 77

7.04

8 96

7.20

9 16

•26.7

8.65

6.86

8 64

6.94

8 84

7.10

9 03

7.26

9 23

26.8

8 62

6.92

8.71

6.99

8 91

7.15

9 10

7.81

9 30

26.9

8 68

6.97

8.78

7.05

8 98

7.21

9.17

7.87

9 37

27.0

8 75

7.08

8.85

7.11

9 05

7.27

9 23

7.42

9 44

27.1

8 82

7.08

8 91

7.16

9.11

7.32

9 30

7.48

9 51

27 2

8 89

7.14

8 98

7 .22

9 18

7.88

9 37

7.54

9 58

27'i

8 95

7.19

9 05

7.27

9 25

7.48

9.44

7.59

9 65

27.4

9.02

7.25

9.12

7.38

9.32

7.49

9.51

7.65

9 71

27.5

9 09

7.80

9.19

7.88

9 38

7.54

9 58

7.70

9 78

27.6

9 16

7.36

9 26

7.44

9 46

7.60

9 65

7.76

9 85

27.7

9 22

7.41

9 32

7.49

9.52

7.65

9 72

9 91

27.8

9.29

7.47

9.39

7.55

1 9 59

7.71

9.79

7.87

9 98

27 9

9 36

7.52

9.46

7.60

9 65

7.76

9.86

7.98

10 05

XVI]

Table.— Continued.

WINES

213
6

21° C.

22°

C.

23°

C.

24°

C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

5.34

6 86

5.50

7.06

5.66

7.24

5.81

7.45

5.97

23.0

5.10

6.93

5.56

7 13

5.71

7.32

5.87

7.52

6.03

23.1

5.46

7.00

5.61

7.20

5.77

7.39

5.93

7.59

6.08

23.2

5.51

7 07

5.67

7.27

5.83

7.46

5.98

7 66

6.14

23.3

5.57

7.14

5.73

7.34

5.89

7.53

6.04

7.73

6.20

23.4

5.63

7 21

5.78

7.41

5.94

7.60

6.10

7.80

6.25

23.5

5.69

7.28

5.84

7 48

6.00

7.67

6.15

7 87

6.31

23.6

5.74

7.36

5.89

7 55

6.06

7.74

6.21

7.94

6.37

23.7

5.80

7.42

5.95

7.62

6.11

7.81

6.27

8 00

6.42

23.8

5.86

7 49

6.01

7 69

6.17

7.88

6.32

8.07

6.48

23.9

5.92

7.56

6.07

7 76

6.22

7.96

6.38

8.14

6.53

24.0

5.97

7.63

6.12

7.83

6.28

8 02

6.44

8 21

6.59

24.1

6.03

7.70

6.18

7 90

6.34

8.09

6.49

8.28

6.65

24.2

6.08

7.77

6.24

7.97

6.39

8 16

6.55

8 35

6.70

24.3

6.14

7 84

6.29

8 04

6.45

8 23

6.60

8.42

6.76

24.4

6.20

7 91

6.35

8 10

6.50

8 30

6.66

8 48

6.81

24.5

6.25

7 98

6.41

8.17

6.56

8 37

6.72

8.55

6.87

24.6

6.31

8 05

6.46

8 24

6.62

8.44

6.77

8.62

6.93

24.7

6.36

8 12

6.52

8 31

6.67

8 51

6.83

8 69

6.98

24 8

6.42

8 19

6.58

8 38

6.73

8 68

6.89

8.76

7.04

24.9

6.47

8 26

6.63

8.45

6.79

8 64

6.94

8 84

7.10

25.0

6.53

8 33

6.69

8.52

6.84

8 71

7.00

8 91

7.15

25.1

6.59

8 40

6.75

8 59

6.90

8.78

7.06

8 98

7.21

25.2

6.64

8 47

6.80

8 66

6.96

8 85

7.11

9 05

7.27

25.3

6.70

8 54

6.86

8.73

7.01

8 92

7.17

9.12

7.33

25.4

6.75

8 61

6.92

8 80

7.07

8 99

7.23

9.19

7.38

25.5

6.81

8 68

6.97

8 86

7.12

9 06

7.28

9 26

7.44

25.6

6.87

8 75

7.03

8 93

7.18

9 13

7.34

9 33

7.50

25.7

6.92

8 82

7.08

9 00

7.23

9 20

7.40

9 39

7.55

25.8

6.98

8 89

7.14

9.07

7.29

9 27

7.45

9 46

7.61

25.9

7.03

8 95

7.19

9.14

7.35

9 34

7.51

9 53

7.67

26.0

7.09

9 02

7.25

9 21

7.40

9 41

7.56

9 60

7.73

26.1

7.14

9 09

7.30

9 28

7.46

9 48

7.62

9 67

7.78

26.2

7.20

9 16

7.36

9 35

7.51

9 55

7.68

9 74

7.84

26.3

7.25

9 22

7.41

9.42

7.57

9 61

7.73

9 81

7.90

26.4

7.31

9 29

7.47

9 49

7.63

9 68

7.79

9 88

7.95

26.5

7.36

9 36

7.52

9 55

7.68

9 75

7.85

9 95

8.01

26.6

7.42

9 43

7.58

9 62

7.74

9 82

7.90

10 02

8.07

26.7

7.47

9 49

7.63

9 69

7.79

9 89

7.96

10 09

8.12

26 8

7.53

9 56

7.69

9.76

7.85

9 96

8.02

10 16

8.18

26.9

7.59

9 63

7.74

9 83

7.91

10 03

8.07

10 23

8.24

27.0

7.65

9 70

7.80

9 90

7.96

10 10

8.13

10 30

8.29

27.1

7.70

9 76

7.85

9 97

8.02

10 17

8.18

10 37

8.35

27.2

7.76

9 83

7.91

10 03

8.07

10 24

8.24

10 44

8.40

27.3

7.81

9 90

7.96

10 10

8.13

10 31

8.30

10.61

8.46

27 1

7.86

9 97

8.02

10 17

8.18

10 38

8.35

10 58

8.52

27.5

7.92

10 03

8.07

10 24

8.24

10.45

8.41

10 65

8.57

27.6

7.97

10 10

8.13

10 31

8.30

10 51

8.46

10 72

8.63

27.7

8.03

10 17

8.18

10 38

8 . ■ 6

10.68

8.52

10 79

8.69

27.8

8.08

10.24

8.24

10 45

8.41

10 65

8.58

10.86

8.74

27.9

214
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

'C.

18

C.

19"

C.

20

■c.

21° C.

SCALE

BEADING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

28.0

9 43

7.58

9 53

7.66

9.72

7.82

9 92

7.98

10.12

28.1

9 50

7.64

9 59

7.71

9.79

7.87

9 99

8.04

10.18

28.2

9 57

7.69

9 66

7.77

9 86

7.93

10.06

8.09

10.25

28.3

9 64

7.75

9 73

7.82

9 92

7.98

10.13

8.15

10.32

28.4

9.70

7.80

9 80

7.88

9 99

8.04

10.19

8.20

10.39

28.5

9 77

7.86

9 86

7.93

10 06

8.09

10.26.

8.26

10.46

28.6

9 84

7.91

9 93

7.99

10 13

8.15

10.32

8.31

10.62

28.7

9 91

7.97

10 00

8.04

10 19

8.20

10 39

8.36

10.69

28.8

9 97

8.02

10 07

8.10

10 26

8.26

10 46

8.42

10.66

28.9

10 04

8.08

10 13

8.15

10 32

8.31

10.52

8.47

10.73

29.0

10 10

8 13

10 19

8.20

10 39

8.36

10.69

8.53

10.79

29.1

10 17

8.18

10 26

8.26

10 46

8.42

10.66

8.58

10.86

29.2

10 24

8.24

10 33

8.31

10 52

8.47

10.73

8.64

10.93

29.3

10 30

8.29

10 40

8.37

10 59

8.53

10.79

8 69

1100

29.4

10 36

8.34

10 46

8.42

10 66

8.58

10.86

8.74

11.06

29.5

10 43

8.40

10 52

8.47

10 73

8.64

10 93

8.80

11 13

29.6

10 50

8.45

10 59

8.53

10 79

8.69

10.99

8.85

11.20

29.7

10 56

8.50

10 66

8.58

10 86

8.74

11.06

8.91

11 27

29.8

10 63

8.56

10 72

8.63

10 93

8.80

11.12

8.96

11.33

29.9

10 69

8.61

10 79

8.69

10 99

8.85

11.19

9.02

11.39

30.0

10.76

8.66

10 86

8.74

11 06

8.91

11.26

9.07

11 46

30.1

10 83

8.72

10 93

8.80

11.12

8.96

11.32

9.12

11.52

30.2

10 89

8.77

10 99

8.85

11.18

9.02

11 38

9.18

11.69

30.3

10 95

8.82

11 05

8.90

11 25

9.07

11.45

9.23

11.66

30.4

11 02

8.88

11.12

8.96

11.31

9.12

11.51

9.28

11 72

30.5

11 08

8.93

11.18

9.01

11 38

9.18

11.58

9.34

11.79

30.6

11.15

8.98

11.26

9.06

11 44

9.23

11.64

9.39

11.86

30.7

11.21

9.04

11.31

9.12

11.51

9.28

11.71

9.44

11.92

30.8

11 28

9.09

11.38

9.17

11.58

9.34

11.78

9.50

11.99

30.9

11 34

9.14

11 44

9.22

11.64

9.39

11.84

9.55

12.06

31.0

11.41

9.19

11.61

9.28

11 71

9.44

11.91

9.60

12 12

31.1

11 47

9.25

11.57

9.33

11.77

9.49

11.97

9.66

12.18

31.2

11 54

9.30

11 64

9.38

11.84

9.55

12.04

9.71

12.26

31.3

11 60

9.35

11.70

9.43

11.90

9.60

12.11

9.76

12.32

31.4

11 66

9.40

11.77

9.49

11.97

9.65

12.17

9.82

12.38

31.5

11.73

9.46

11.83

9.54

12.03

9.71

12.24

9.87

12.46

31.6

11 79

9.51

11.90

9.59

12.10

9.76

12.30

12.51

31.7

11 86

9.56

11 96

9.65

12.16

9.81

12.37

9.98

12.68

31.8

11 92

9.62

12.03

9.70

12.23

9.87

12.43

10.03

12.64

31.9

11 99

9.67

12.09

9.75

12.29

9.92

12.50

10.09

12.71

32.0

12 05

9.72

12.15

9.80

12.36

9.97

12.67

10.14

12.78

32.1

12 12

9.77

12 21

9.86

12.42

10.03

12.63

10.19

12.84

32.2

12.18

9.83

12.28

9.91

12.49

10. OS

12.70

i

12.91

32.3

12.24

9.88

12.34

9.96

12.55

10.13

12.76

10.30

12.97

32.4

12 31

9.93

12.40

10.02

12.62

10.19

12.83

'

13.04

32.5

12 37

9.98

12 47

10.07

12.68

10.24

12.89

13.10

32.6

12.43

10.04

12.54

10.12

12.75

10.29

12.96

13.17

32.7

12.50

10.09

12.60

10.17

12.81

10.34

13.03

13.24

32.8

12.56

10.14

12 67

W. 28

12.88

10.40

13.09

10.57

13.30

32.9

12 62

W. 19

12.73

12.94

10.45

13.16

13.37

XVI]

Table. — Continued.

WINES

215
6

21° C.

22

C.

23°

C.

24°

C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

8.14

10 31

8.30

10 51

8.46

10 72

8.63

10 93

8.80

28.0

8.19

10 38

8.35

10 58

8.52

10 79

8.69

10 99

8.85

28.1

8.25

10 45

8.41

10 65

8.58

10 86

8.74

11.06

8.91

28.2

8.30

10 52

8.46

10.72

8.63

10 93

8.80

11.13

8.97

28.3

8.86

10 59

8.52

10 79

8.69

11 00

8.86

11 20

9.02

28.4

8.41

10 66

8.58

10 86

8.74

11 06

8.91

11 27

9.08

28.5

8.47

10 72

8.63

10 93

8.80

11.13

8.97

11.33

9.13

28.6

8.52

10.79

8.69

11 00

8.86

11 20

9.02

11 40

9.19

28.7

8.58

10 86

8.74

11 06

8.91

11 27

9.08

11 47

9.24

28.8

8.64

10 93

8.80

11.13

8.97

11 33

9.13

11 54

9.30

28.9

8.69

11 00

8.86

11 20

9.02

11 40

9.19

11.61

9.36

29.0

8.75

11 06

8.91

11 27

9.08

11 47

9.24

11 68

9.41

29.1

8.80

11.13

8.97

11 33

9.13

11 54

9.30

11 75

9.47

29.2

8.86

11 20

9.02

11.40

9.19

11 60

9.35

11.81

9.52

29.3

8.91

11 27

9.08

11 47

9.24

11 67

9.41

11.88

9.58

29.4

8.97

11 33

9. IS

11 54

9.30

11 74

9.46

11 94

9.63

29.5

9.02

11 39

9.18

11 60

9.35

11.81

9.52

12 01

9.69

29.6

9.08

11 46

9.24

11 67

9.41

11.87

9.57

12 08

9.75

29.7

9.13

11.53

9.29

11.74

9.46

11 94

9.63

12.15

9.80

29.8

9.18

11 60

9.35

11.81

9.52

12.01

9.69

12 22

9.86

29.9

9:24

11 66

9.40

11 87

9.57

12 08

9.74

12 29

9.91

30.0

9.29

11 73

9.46

11 93

9.63

12 14

9.80

12 36

9.97

30.1

9.34

11 79

9.51

12 00

9.68

12 21

9.85

12 42

10.02

30.2

9.40

11.86

9.57

12 07

9.74

12 28

9.91

12 49

10.08

30.3

9.45

11 93

9.62

12 13

9.79

12 34

9.96

12 56

10.18

30.4

9.50

11 99

9.67

12 20

9.85

12 41

10.02

12 63

10.19

30.5

9.56

12 06

9.73

12 27

9.90

12 48

10.07

12 70

10.24

30.6

9.61

12 13

9.78

12 34

9.96

12 55

10.13

12 77

10.80

30.7

9.67

12 19

9.84

12 40

10.01

12 61

10.18

12 84

10.36

30.8

9.72

12 26

9.89

12 47

10.07

12 68

10.24

12 90

10.41

30.9

9.77

12 32

9.95

12 54

10.12

12 75

10.29

12 97

10.47

31.0

9.83

12 39

10.00

12 60

10.17

12 82

10.35

13 04

10.52

31.1

9.88

12 46

10.05

12 67

10.23

12 89

10.40

13.11

10.58

31.2

9.94

12 52

10.11

12 74

10.28

12 95

10.46

13.17

10.63

31 3

9.99

12 59

10.16

12 81

10.34

13 02

10.51

13 24

10.69

31.4

10.04

12 66

10.22

12 87

10.39

13 09

10.57

13.31

10.74

31.5

10.10

12 72

10.27

12 94

10.45

13 15

10.62

13.37

10.80

31.6

10.15

12 79

10.32

13 01

10.50

13 22

10.68

13 44

10.86

31.7

10.21

12 85

10.38

13 07

10.55

13 29

10.73

13.51

10.91

31.8

10.26

12 92

10.43

13 14

10.61

13 35

10.78

13.57

10.97

31.9

10.31

12 99

10.49

13 20

10.66

13 42

10.84

13 64

11.02

32.0

10.37

13 05

10.54

13.27

10.72

13 49

10.90

13.71

11.08

32.1

10.42

13 12

10.59

13 34

10.77

13 65

10.95

13.77

11.13

32 2

10.48

13 18

10.65

13 40

10.83

13 62

11.01

13 84

11.19

32 ;;

10.53

13 25

10.70

13 47

10.88

13 69

11.06

13.91

11.24

32.4

10.58

13 32

10.76

13 53

10.94

13 75

11.11

13 97

11.80

32 5

10.64

13 38

10.81

13 60

10.99

13 82

11.17

14 04

11.85

32 6

10.69

13 45

10.87

13 66

11.04

13 89

14.11

11.41

32.7

10.75

13 51

10.92

13 73

11.10

13 95

11.2S

14 17

11.46

32 8

10.80

13 58

10.97

13 80

11.15

14 02

//..»'.;

14 24

11.52

32 9

216

METHODS OF ANALYSIS

[Chap.

Table 17 —Alcohol

17.5

•c.

18'

C.

19

C.

20

'C.

21° c.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

33.0

12.69

10.24

12.79

10.33

13 01

10.50

13 22

10.68

13 43

33.1

12.76

10.30

12.86

10.38

13.07

10.56

13 28

10.73

13 50

33.2

12.82

10.35

12 92

10.43

13 13

10.61

13 35

10.79

13 56

33.3

12 88

10.40

12 99

10.49

13 20

10.66

13 41

10.84

13 63

33.4

12.95

10.45

13.05

10.54

13.26

10.71

13.48

10.89

13 69

33.5

13.01

10.50

13.11

10.59

13 32

10.77

13 54

10.95

13 76

33.6

13 08

10.56

13.18

10.64

13 39

10.82

13 61

11.00

13.82

33.7

13 14

10.61

13 24

10.70

13 45

10.87

13 67

11.05

13 89

33.8

13 20

10.66

13 30

10.75

13 52

10.93

13.74

11.10

13 95

33.9

13 26

10.71

13 37

10.80

13 58

10.98

13 80

11.16

14 02

34.0

13 33

10.77

13.43

10.85

13 64

11.03

13 86

11.21

14 08

34.1

13 39

10.82

13.49

10.91

13.71

11.08

13 93

11.26

14 15

34.2

13 45

10.87

13 56

10.96

13 77

11.13

13 99

11. SI

14 21

34.3

13.52

10.92

13 62

11.01

13 83

11.19

14.06

11.36

14 27

34.4

13.58

10.97

13 68

11.06

13 90

11.24

14 12

11.41

14 34

34.5

13 64

11.03

13 75

11.11

13 96

11.29

14 18

11.47

14 40

34.6

13.70

11.08

13 81

11.16

14 02

11.34

14 25

11.52

14 47

34.7

13.77

11.13

13.87

11.22

14.08

11.39

14 31

11.57

14 53

34.8

13 83

11.18

13 94

11.27

14 14

11-44

14 37

11.62

14 59

34.9

13 89

11.23

14 00

11.32

14 20

U.49

14 43

11.67

14 66

35.0

13 96

11.28

14 06

11.37

14 27

11.55

14 50

11.73

14 72

35.1

14 02

11.33

14.13

11.42

14 33

11.60

14 56

11.78

14 78

35.2

14.08

11.38

14 19

11.47

14 39

11.65

14.62

11.83

14 85

35.3

14.14

11.44

14 25

11.52

14 46

11.70

14 69

11.88

14 91

35.4

14 21

II.49

14 31

11.57

14.52

11.75

14.75

11.93

14 97

35.5

14 27

11.54

14 38

11.63

14 59

11.81

14.81

11.99

15 04

35.6

14 33

11.59

14.44

11.68

14 65

11.86

14 87

12.04

15 10

35.7

14.39

11.64

14.50

11.73

14.71

11.91

14 94

12.09

15 16

35.8

14.46

11.69

14 56

11.78

14.78

11.98

15.00

12.14

15 23

35.9

14 52

11.74

14 63

11.83

14 84

12.01

15.06

12.19

15 29

36.0

14.58

11.79

14 69

11.88

14 90

12.06

15 13

12.24

15 35

36.1

14.64

11.85

14.75

11.94

14 97

12.11

15 19

12.30

15 42

36.2

14.71

11.90

14.81

11.99

15 03

12.16

15 25

12.35

15 48

36.3

14.77

11.95

14 88

12.04

15 09

12.22

15 32

12.40

15 54

36.4

14.83

12.00

14.94

12.09

15 16

12.27

15 38

12.45

15 61

36.5

14 89

12.05

15 00

12.14

15 22

12.32

15 44

12.50

15 67

36.6

14.96

12.10

15.06

12.19

15 28

12.37

15 51

12.56

15 73

36.7

15 02

12.15

15.13

12.24

15 35

12.42

15 57

12.61

15 80

36.8

15 08

12.20

15 19

12.29

15 41

12.47

15 63

12.66

15 86

36.9

15.14

12.25

15 25

12.34

15 47

12.53

15 70

12.71

15 92

37.0

15 20

12.30

15.31

12.40

15 53

12.58

15 76

12.77

15 99

37.1

15 27

12.36

15.38

12.45

15 60

12.63

15 82

12.82

16 05

37.2

15 33

12.41

15 44

12.50

15 66

12.68

15 89

12.87

16.11

37.3

15 39

12.46

15 50

12.55

15.72

12.73

15 95

12.92

16 18

37.4

15.45

12.51

15 56

12.60

15.79

12.78

16 01

12.97

16 24

37.5

15 51

12.56

15 63

12.65

15 85

12.84

16 08

13.03

16 30

37.6

15.57

12.61

15.69

12.70

15 91

12.89

16.14

13.08

16 37

37.7

15.64

12.66

15.75

12.75

15.97

12.94

16 20

13.13

16 43

37.8

15.70

12.71

15 81

12.81

16 04

12.99

16 26

13.18

16 49

37.9

15.76

12.76

15 88

12.86

16 10

13.04

16 33

tS 98

16 56

XVI]

Table. — Continued.

WINES

217
6

21° C.

22°

C.

23<

C.

24

C.

25

■c.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

10.85

13.64

11.03

13 86

11.21

14 09

11.39

14 31

11.57

33.0

10.91

13 71

11.08

13 93

11.26 .

14.15

11.44

14.38

11.63

33.1

10.96

13 78

11.13

13 99

11.31

14.22

11.49

14.44

11.68

33.2

11.02

13 84

11.19

14.06

11.87

14 28

11.55

14 51

11.74

33.3

11.07

13.91

11.24

14 13

11.42

14.35

11.60

14 58

11.79

33.4

11.12

13.97

11.29

14.19

11.48

14.42

11.66

14 64

11.85

33.5

11.17

14.04

11.35

14.26

11.53

14.48

11.71

14.71

11.90

33.6

11.23

14.11

11.40

14 32

11.58

14.55

11.77

14.78

11.96

33.7

11.28

14 17

11.45

14 39

11.64

14.62

11.82

14.85

12.01

33.8

11.83

14.24

11.51

14 45

11.69

14.68

11.88

14.91

12.07

33.9

11.38

14.30

11.56

14.52

11.75

14.75

11.93

14.98

12.12

34.0

u. U

14.37

11.61

14.59

11.80

14.81

11.98

15 05

12.18

34.1

11.49

14.43

11.67

14.65

11.85

14.88

12.04

15.11

12.23

34.2

11.54

14.50

11.72

14.72

11.91

14.95

12.09

15.18

12.29

34.3

11.59

14.57

11.78

14.78

11.96

16.01

12.15

15.25

12.34

34.4

11.65

14.63

11.83

14.85

12.02

15.08

12.20

15 31

12.40

34.5

11.70

14.70

11.88

14 91

12.07

15 14

12.26

15 38

12.45

34.6

11.75

14.76

11.94

14 98

12.12

15 21

12.81

15.45

12.51

34.7

11.81

14.83

11.99

15 05

12.18

15 28

12.36

15 51

12.56

34.8

11.86

14.89

12.04

15.11

12.23

15 34

12.42

15 58

12.62

34.9

11.91

14 96

12.10

15 18

12.28

15 41

12.47

15 65

12.67

35.0

11.96

15.03

12.15

15 24

12.34

15.47

12.53

15.71

12.73

35 . 1

12.02

15 09

12.20

15.31

12.89

15 54

12.58

15 78

12.78

35.2

12.07

15.15

12.25

15 37

12.44

15 61

12.64

15 85

12.84

35.3

12.12

15 22

12.31

15.44

12.50

15 67

12.69

15 91

12.89

35.4

12.17

15 28

12.36

15 50

12.55

15 74

12.75

15 98

12.95

35.5

12.23

16 34

12.41

15 56

12.60

15 80

12.80

16 05

IS. 00

35.6

12.28

15 41

12.47

15 63

12.66

15 87

12.85

16 11

13.05

35.7

12.33

15.47

12.52

15 69

12.71

15.93

12.91

16.18

13.11

35.8

12.38

15 53

12.57

15 76

12.76

16 00

12.96

16 24

13.16

35.9

12.43

15 59

12.62

15 82

12.82

16 06

13.02

16 31

13.21

36.0

12.49

15 66

12.68

15 89

12.87

16 13

13.07

16 37

13.27

36.1

12.54

15 72

12.78

15 95

12.92

16 19

13.12

16 44

13.32

36.2

12.59

15 78

12.78

16 02

12.98

16.26

18.18

16 50

13.37

36.3

12.64

15 85

12.84

16 08

13.03

16 32

18.23

16 56

13.43

36.4

12.70

15 91

12.89

16 15

13.08

16 39

13.28

16 63

13.48

36.5

12.75

15 97

12.94

16 21

13.14

16 45

13.34

16 69

13.53

36.6

12.80

16 04

12.99

16 28

13.19

16 52

13.39

16.76

13.59

36.7

12.85

16.10

13.05

16 34

ts .,">

16 58

13.44

16 82

13.64

36.8

12.91

16.16

13.10

16.40

13.29

16 65

13.49

16 89

13.70

36.9

12.96

16 23

18.15

16 47

18.35

16 71

13.55

16 95

18.75

37.0

13.01

16 29

13.20

16 53

13.40

16 77

13.60

17 02

13.80

37 1

13.06

16 35

13.26 .

16 60

13.45

16 84

13.65

17 08

13.86

37.2

13.11

16.42

13.31

16.66

18.50

16 90

18.71

17 15

13.91

37.3

13.16

16 48

13.36

16.72

18.56

16 97

13.76

17 21

13.96

37.4

13.21

16 54

13.41

16 79

13.61

17 03

13.81

17 27

14.02

37.5

13.27

16.61

13.46

16 85

13.66

17.09

18.87

17 34

14.07

37.6

13.32

16 67

13.52

16.92

18.72

17.16

13.92

17.40

14.12

37.7

13.87

16.73

13.57

16 98

13.77

17.22

18.97

17.46

14.17

37.8

13.42

16 80

18.62

17.04

13.82

17.28

14-03

17.53

/;.,'.;

37.9

218
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

'C.

18°

C.

19°

C.

20°

C.

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

38.0

15 82

12.81

15 94

12.91

16 16

13.09

16 39

18.28

16 62

38.1

15 88

12.86

16 00

12.96

16 22

13.14

16 46

18.33

16 68

38.2

15 94

12.91

16 06

13.01

16 29

13.19

16 51

13.38

16 75

38.3

16 01

12.96

16.12

13.06

16 35

13.25

16 57

13.44

16 81

38.4

16 07

13.02

16 18

13.11

16 41

18.80

16.64

is. 49

16 87

38.5

16 13

13.07

16 25

18.16

16 47

18.35

16 70

13.54

16 94

38.6

16 19

13.12

16 31

13.21

16 53

13.40

16 76

18.59

17 00

38.7

16 25

13.17

16 37

13.26

16 60

13.45

16 83

13.64

17 06

38.8

16 31

13.22

16 43

13.31

16 66

13.50

16 89

13.69

17 13

38.9

16 37

13.27

16 49

13.37

16 72

13.55

16 96

13.74

17 19

39.0

16 44

13.32

16 55

18. 42

16 78

13.61

17 01

18.79

17 26

39.1

16 50

13.37

16 61

13.47

16 84

13.66

17 07

13.85

17 31

39.2

16 56

1342

16 67

13.52

16 91

18.71

17 14

18.90

17 38

39.3

16.62

13.47

16 74

13.57

16 97

13.76

17 20

18.95

17 44

39.4

16.68

13.52

16 80

13.62

17 03

18.81

17 26

14.00

17 60

39.5

16 74

13.57

16 86

13.67

17 09

18.86

17 32

14.05

17 56

39.6

16 80

13.62

16 92

13.72

17 15

13.91

17 39

14.10

17 63

39.7

16 87

13.68

16 98

13.77

17 21

13.96

17.45

14.15

17 69

39.8

16 93

13.73

17 04

18.82

17 28

14-02

17 51

14.21

17 76

39.9

16 99

13.78

17 10

13.87

17 34

14-07

17 67

14-26

17 81

40.0

17 05

13.83

17 16

13.92

17 40

14.12

17 63

14-81

17 88

40.1

17.11

13.88

17 23

13.98

17 46

14.17

17 70

14-36

17 94

40.2

17 17

13.93

17 29

14-03

17 52

14.22

17 76

14.41

18 00

40.3

17 23

13.98

17 35

14-08

17 58

14.27

17 82

14-46

18 06

40.4

17 29

14.03

17 41

14-13

17.64

14.82

17 88

14-51

18 12

40.5

17 35

14-08

17 47

14-18

17.71

14-37

17 94

14-56

18 19

40.6

17.41

14-13

17 53

14-23

17.77

U-42

18 01

14-62

18 25

40.7

17.48

14-18

17 59

14-28

17 83

14-47

18 07

14-67

18 31

40.8

17.54

14.23

17 65

14-88

17 89

14-52

18 13

14-72

18 37

40.9

17.60

14-28

17.71

14-38

17 95

14-57

18 19

14.77

18 43

41.0

17.66

14-33

17 77

14-43

18 01

14-62

18 25

H.82

18 49

41.1

17 72

14-38

17 84

14-48

18 07

14-68

18 31

14.87

18 56

41.2

17.78

14-43

17 90

14.53

18 13

14-78

18 37

14-92

18 62

41.3

17 84

14-48

17 96

14-58

18 20

14.78

18 44

14-97

18 68

41.4

17.90

14.53

18 03

14-68

18 26

14-83

18 60

15.03

18 74

41.5

17 96

14-58

18 08

14.68

18 32

14-88

18 56

15.08

18 80

41.6

18 02

14-63

18 14

14.73

18 38

14-98

18 62

15.13

18 86

41.7

18 08

14-68

18 20

14.78

18 44

14-98

18 68

15.18

18 93

41.8

18 14

14.73

18 26

14.83

18 50

15.03

18 74

15.28

18 99

41.9

18 20

14.78

18 32

14.88

18 56

15.08

18 81

15.28

19 05

42.0

18 27

14-83

18 38

14.93

18 62

15.18

18 87

15.38

19.11

42.1

18 33

14-88

18 44

14-98

18 68

15.18

18 93

15.88

19 17

42.2

18 39

14-98

18 50

15.03

18 74

15.28

18 99

15.43

19 23

42.3

18 45

14-98

18 56

15.08

18 80

15.28

19 05

15.48

19 29

42.4

18.51

15.03

18.62

15.13

18 87

15.83

19.11

15.53

19 36

42.5

18 57

15.08

18 68

15.18

18 93

15.88

19 17

15.58

19 42

42.6

18 63

15.13

18 75

15.23

18 99

15.48

19 23

15.63

19 48

42.7

18 69

15.18

18 81

16.88

19 05

15.48

19 29

15.69

19 54

42.8

18 75

15.23

18 87

15.83

19.11

15.53

19 36

15.74

19 60

42.9

18 81

15.28

18 93

15.88

19 17

15.58

19 42

15.79

19 66

\

VIj

WINES

219

Table.-

-Continued.

6

21° C.

22

C.

23"

C.

24°

C.

25

'C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
BEADING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

IS. 47

16 86

13.67

17.11

13.87

17.35

14 08

17.59

14-28

38.0

1S.5S

16 92

13.72

17.17

13.93

17.41

14.13

17.66

14.83

38.1

IS. 58

16 99

13.78

17 23

13.98

17.47

14- 18

17.72

11.38

38.2

13.63

17 05

13.83

17 30

14-03

17.54

14.23

17 78

14-48

38.3

13.68

17.11

13.88

17.36

14- 08

17.60

14-29

17.85

14-49

38.4

13.73

17.18

13.93

17 42

14-14

17.66

14.34

17.91

14.54

38.5

13.79

17 24

13.98

17.48

14-19

17 73

14.39

17 97

14-59

38.6

13.84

17 30

14M

17 55

14M

17 79

14-44

18.04

14-64

38.7

13.89

17 36

14-09

17.61

14-29

17 85

14-49

18.10

14-70

38.8

13.94

17 43

14-14

17.67

14.34

17.92

14.55

18 16

14.75

38.9

13.99

17 49

14-19

17.74

14-40

17 98

14. 60

18 23

14. 80

39.0

1405

17 55

14-24

17 80

14.45

18 04

14-65

18 29

14-85

39.1

14.10

17.62

14-30

17 86

14-50

18.11

14-70

18.35

14.91

39.2

14.15

17 68

14.35

17 92

14.55

18.17

14.76

18 42

14.96

39.3

14.20

17.74

14-40

17.99

14. 60

18 23

14. 81

18 48

15.01

39.4

14.25

17.81

14-45

18 05

14.66

18 30

14.86

18.54

15.06

39.5

1480

17 87

14-50

18.11

14-71

18 36

14.91

18 61

15.12

39.6

I486

17 93

14-56

18.18

14-76

18 42

14-96

18 67

15.17

39.7

14.41

17 99

14-61

18 24

14. 81

18.48

15.02

18 73

15.22

39.8

14-46

18 06

14.66

18 30

14-87

18.55

15.07

18 80

15.27

39.9

14.51

18 12

14.71

18 36

14.92

18 61

15.12

18 86

15.82

40.0

14-56

18 18

14.77

18 43

14.97

18 67

15.17

18 92

15.38

40.1

14-61

18 24

14-82

18 49

15.02

18.74

15.22

18 99

15.48

40.2

14-67

18 30

14.87

18 55

15.07

18 80

15.27

19 05

15.48

40.3

14-72

18 37

14-92

18 61

15.12

18.86

15.88

19.11

15.53

40.4

14-77

18 43

14.97

18 68

15.17

18 92

15.88

19 18

15.59

40.5

14-82

18 49

15.03

18.74

15.23

18 99

15.43

19 24

15.64

40.6

14-87

18 55

15.08

18 80

15.28

19 05

15.48

19 30

15.69

40.7

14-92

18 61

15.18

18 86

15.38

19 11

15.53

19 37

15.74

40.8

14-97

18 68

15.18

18 93

15.38

19 18

15.59

19 43

15.80

40.9

15.03

18 74

15.28

18 99

15.43

19 24

15.64

19 49

15.85

41.0

15.08

18 80

15.28

19 05

15.48

19 30

15.69

19 56

15.90

41.1

15.18

18 86

15.88

19.11

15.53

19 36

15.74

19 62

15.95

41.2

15.18

18 93

15.88

19 17

15.58

19 43

15.79

19 68

16.01

41.3

15.23

18 99

15.43

19 24

15.64

19 49

15.84

19 75

16.06

41.4

15.28

19 05

15.48

19 30

15.69

19 55

15.90

19 81

16.11

41.5

15.88

19 11

15.58

19 36

15.74

19 61

15.95

19 87

16.16

41.6

15.88

19 17

15.58

19 42

15.79

19 68

16.00

19 94

16.21

41.7

15.48

19 23

15.63

19 48

15.84

19 74

16.05

20 00

16.27

41.8

15.48

19 29

15.69

19 55

15.89

19 80

16.10

20 06

16.82

41.9

15.53

19 36

15.74

19 61

15.94

19 86

16.16

20 13

16.87

42.0

15.58

19 42

15.79

19 67

15.99

19 93

16.21

20 19

16. 42

42.1

15.68

19 48

15.84

19 73

16.05

19 99

16.26

20 25

16.48

42.2

15.69

19 54

15.89

19 80

16.10

20 05

16.81

20 31

16.53

42.3

15.74

19 60

15.94

19 86

16.15

20 11

16.86

20 38

16.58

42.4

15.79

19 66

15.99

19 92

16.20

20 18

16. 41

20.44

te.es

42.5

15.84

19 72

16.04

19 98

16.25

20 24

16. 47

20 50

16.79

42.6

15.89

19 79

16.09

20 04

16.80

20 30

16.62

20 57

16.74

42.7

15.94

19 85

I6.14

20 10

16.85

20 36

16.57

20 63

16.79

42.8

15.99

19 91

16.19

20 17

16. 41

20 43

16.62

20 69

16.84

42.9

220

METHODS OF ANALYSIS

Chap.

Table 17 —Alcohol

17.5

C.

18

°C.

19°

C.

20°

C.

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

1 weight

volume

weight

volume

weight

volume

43.0

18 87

15.33

18 99

15.43

19 23

15.63

19 48

15.84

19 72

43.1

18 93

15.38

19.05

15.48

19 29

15.68

19 54

15.89

19 79

43.2

18.99

15.43

19.11

15.53

19 35

15.73

19 60

15.94

19 85

43.3

19.05

15.48

19.17

15.58

19 41

15.78

19 66

15.99

19 91

43.4

19.11

15.53

19.23

15.63

19 47

15.83

19 72

16.04

19 97

43.5

19.17

15.58

19 29

15.68

19 53

15.88

19 79

16.09

20 03

43.6

19 23

15.63

19 35

15.73

19 59

15.93

19 85

16.14

20 09

43.7

19 29

15.68

19.41

15.78

19 65

15.98

19 91

16.19

20 16

43.8

19 35

15.73

19.47

15.83

19 72

16.03

19 97

16.24

20 21

43.9

19.40

15.78

19 53

15.88

19.78

16.08

20 03

16.29

20 27

44.0

19.46

15.83

19 59

15.93

19 84

16.13

20 09

16.34

20 34

44.1

19.52

15.88

19 65

15.98

19.90

16.18

20 15

16.39

20 40

44.2

19 58

15.93

19.71

16.03

19 96

16.23

20 21

16.44

20 46

44.3

19.64

15.98

19.77

16.08

20 02

16.28

20 27

16.49

20 52

44.4

19.70

16.02

19 83

16.13

20.08

16.33

20 33

16.55

20 58

44.5

19 76

16.07

19 89

16.18

20.14

16.38

20 39

16.60

20 64

44.6

19.82

16.12

19 95

16.23

20 20

16.43

20 45

16.65

20 70

44.7

19 88

16.17

20 01

16.27

20 26

16.48

20 52

16.70

20 76

44.8

19 94

16.22

20 07

16.32

20 32

16.53

20 58

16.75

20 82

44.9

20.00

16.27

20.12

16.37

20 38

16.58

20.64

16.80

20 88

45.0

20.06

16.32

20.18

16.42

20 44

16.63

20.70

16.85

20 95

45.1

20 12

16.37

20.24

16.47

20 50

16.68

20 76

16.90

21 01

45.2

20.18

16.41

20 30

16.52

20 56

16.73

20 82

16.95

21 07

45.3

20.24

16.46

20.36

16.57

20 62

16.78

20 88

17.00

21 13

45.4

20 29

16.51

20.42

16.62

20 68

16.83

20 94

17.05

21 19

45.5

20 35

16.56

20 48

16.67

20.74

16.88

21.00

17.10

21 25

45.6

20.41

16.61

20 54

16.72

20 80

16.93

21 06

17.15

21 31

45.7

20 47

16.66

20 60

16.76

20 86

16.98

21 12

17.20

21 37

45.8

20 53

16.71

20 66

16.81

20 92

17.03

21 18

17.25

21 43

45.9

20 59

16.76

20.72

16.86

20.98

17.08

21 24

17.30

21 49

46.0

20 65

16.80

20 78

16.91

21 04

17.13

21 30

17.35

21 54

46.1

20 71

16.85

20.83

16.96

21 10

17.18

21.36

17.40

21 60

46.2

20 76

16.90

20 89

17.01

21 16

17.23

21.42

17.45

21 66

46.3

20 82

16.95

20.95

17.06

21 22

17.28

21 48

17.50

21 72

46.4

20 88

17.00

21.01

17.11

21 28

17.33

21 54

17.55

21 78

46.5

20 94

17.05

21 07

17.16

21 34

17.38

21 60

17.60

21 84

46.6

21.00

17.10

21 13

17.21

21 40

17.43

21 66

17.65

21 90

46.7

21 06

17.15

21.19

17.26

21 46

17.48

21 72

17.70

21 96

46.8

21.12

17.20

21 25

17.31

21 52

17.53

21 78

17.75

22 02

46.9

21 18

17.25

21.31

17.36

21.58

17.58

21 84

17.80

22 09

47.0

21.24

17.30

21 37

17.41

21.64

17.63

21 90

17.85

22 16

47.1

21 30

17.35

21 43

17.46

21 70

17.68

21 96

17.90

22 21

47.2

21.36

17.40

21 49

17.51

21 76

17.73

22 02

17.95

22 27

47.3

21.42

17.45

21 55

17.56

21 82

17.78

22 08

18.01

22 33

47.4

21.48

17.50

21 61

17.61

21 88

17.83

22.15

18.06

22 39

47.5

21.54

17.55

21.67

17.66

21 94

17.88

22 21

18.11

22 45

47.6

21.60

17.60

21 73

17.71

22 00

17.94

22.27

18.16

22 51

47.7

21 66

17.65

21.79

17.76

22 06

17.99

22 33

18.21

22 58

47.8

21.72

17.70

21.85

17.81

22.12

18.04

22 39

18.26

22 64

47.9

21.78

17.75

21.91

17.86

22.18

18.09

22.45

18.31

22 70

XVI]

Table. — Continued.

WINES

221
6

21° C.

22°

C.

23°

C.

24°

C.

25°

C.

SCALE

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

HEADING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

16.04

19 97

16.24

20 23

16.46

20.49

16.67

20.75

16.90

43.0

16.09

20 03

16.30

20.29

16.51

20.55

16.73

20 82

16.95

43.1

16.14

20 09

16.35

20.35

16.56

20 61

16.78

20 88

17.00

43.2

16.19

20 15

16.40

20 41

16.61

20 68

16.83

20 94

17.05

43.3

16.24

20 21

16.45

20 47

16.66

20.74

16.88

21 01

17.10

43.4

16.29

20 28

16.50

20 53

16.71

20 80

16.93

21 07

17.16

43.5

16.84

20 34

16.55

20 60

16.76

20.86

16.98

21 13

17.21

43.6

16.40

20 40

16.60

20 66

16.82

20 93

17.04

21 19

17.26

43.7

16.45

20 46

16.65

20 72

16.87

20.99

17.09

21 25

17.31

43.8

16.50

20 52

16.70

20 78

16.92

21 05

17.14

21 32

17.36

43.9

16.55

20 58

16.76

20 84

16.97

21.11

17,19

21 38

17.41

44.0

16.60

20 64

16.81

20 90

17.02

21.17

17.24

21 44

17.47

44.1

16.65

20 71

16.86

20 96

17.07

21.23

17.29

21 50

17.52

44.2

16.70

20 77

16.91

21 02

17.12

21.30

17.35

21 57

17.57

44.3

16.75

20 83

16.96

21 09

17.17

21.36

17.40

21 63

17.62

44.4

16.80

20 89

17.01

21 15

17.22

21.42

17.45

21 69

17.67

44.5

16.85

20 95

17.06

21 21

17.28

21.48

17.50

21.75

17.73

44.6

16.90

21 01

17.11

21 27

17.33

21.54

17.55

21.81

17.78

44.7

16.95

21 07

17.16

21 33

17.38

21 60

17.60

21 88

17.83

44.8

17.01

21 13

17.21

21 39

17.43

21.67

17.65

21 94

17.88

44.9

17.06

21 19

17.26

21.45

17.48

21 73

17.71

22 00

17.98

45.0

17.11

21 25

17.31

21 52

17.53

21.79

17.76

22.06

17.98

45.1

17.16

21.31

17.36

21 58

17.58

21 85

17.81

22 13

18.04

45.2

17.21

21 37

17.41

21.64

17.63

21.91

17.86

22.19

18.09

45.3

17.26

21.43

17.46

21 70

17.68

21 98

17.91

22.25

18.14

45.4

17.31

21 49

17.51

21 76

17.73

22 04

17.96

22 32

18.20

45.5

17.36

21 55

17.56

21 82

17.79

22 10

18.02

22 38

18.25

45.6

17.41

21 61

17.61

21 88

17.84

22.16

18.07

22.45

18.30

45.7

17.46

21.67

17.66

21.94

17.89

22 23

18.12

22 51

18.86

45.8

17.51

21 73

17.71

22 01

17.94

22 29

18.17

22.57

18.41

45.9

17.56

21 79

17.76

22 07

17.99

22 35

18.23

22 64

18.47

46.0

17.61

21 85

17.81

22 13

18.04

22 42

18.28

22 70

18.52

46.1

17.66

21 91

17.86

22 19

18.09

22 48

18.88

22 76

18.57

46.2

17.71

21 97

17.91

22 26

18.15

22 54

18.39

22 83

18.63

46.3

17.76

22 03

17.96

22 32

18.20

22 61

18.44

22 89

18.68

46.4

17.81

22 09

18.01

22 38

18.25

22.67

18.49

22.96

18.73

46.5

17.86

22 16

18.06

22 44

18.30

22.73

18.55

23 02

18.79

46.6

17.91

22 22

18.11

22 51

18.86

22 80

18.60

23 08

18.84

46.7

17.96

22 28

18.17

22 57

18.41

22 86

18.65

23 15

18.90

46.8

18.01

22 34

18.22

22 63

18.46

22 92

18.70

23 21

18.95

46.9

18.06

22 41

18.27

22 69

18.51

22 99

18.76

23 28

19.00

47.0

18.11

22.47

18.32

22.76

18.57

23 05

18.81

23 34

19.05

47.1

18.16

22 53

18.38

22 82

18.62

23 12

18.86

23 41

19.11

47.2

18.21

22 59

18.43

22.88

18.67

23 18

18.92

23 47

19.16

47.3

18.26

22 66

18.48

22 94

18.72

23.24

18.97

23 54

19.22

47.4

18.31

22.72

18.53

23.01

18.78

23 31

19.02

23 60

19 57

47.5

18.36

22 78

18.58

23 07

18.83

23 37

19.08

23 67

19.83

47.6

18.42

22.84

18.64

23 13

18.88

23 44

19.13

23 73

19.88

47 .7

18.47

22 91

18.69

23 20

18.98

23 50

19.18

23 80

19.43

47.8

18.52

22.97

18.74

23 26

18.99

23 56

19.24

23 86

19.49

47.9

222
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

C.

18°

C.

19°

C.

20°

C.

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

48.0

21 84

17.80

21 97

17.91

22 24

18.14

22 51

18.36

22 76

48.1

21 90

17.85

22 03

17.96

22 30

18.19

22 57

18.41

22 82

48.2

21.96

17.90

22 09

18.01

22 36

18.24

22 63

18.46

22 88

48.3

22 02

17.95

22 15

18.06

22 42

18.29

22 69

18.51

22 94

48.4

22.08

18.00

22 21

18.11

22 48

18.34

22 75

18.56

23 01

48.5

22.14

18.05

22 27

18.16

22 54

18.89

22 81

18.61

23 07

48.6

22 20

18.10

22 33

18.21

22 60

18.44

22 87

18.66

23 13

48.7

22 26

18.15

22 39

18.26

22 66

18.49

22 93

18.71

23 19

48.8

22 32

18.20

22 45

18.31

22.72

18.54

22 99

18.76

23.26

48.9

22.38

18.25

22 51

18.36

22 78

18.59

23 06

18.81

23 32

49.0

22.44

18.80

22 57

18.41

22 84

18.64

23.12

18.86

23 38

49.1

22 50

18.85

22 63

18.46

22 90

18.69

23 18

18.91

23 44

49.2

22 56

18.40

22 69

18.51

22 96

18.74

23 24

18.96

23 61

49.3

22 62

1845

22.75

18.56

23 02

18.79

23 30

19.02

23 57

49.4

22.68

18.50

22 81

18.61

23 08

18.84

23 36

19.07

23 63

49.5

22 74

18.55

22.87

18.66

23 15

18.89

23 42

19.12

23 69

49.6

22 80

18.60

22 93

18.71

23 21

18.94

23.48

19.17

23 76

49.7

22.86

18.65

22.99

18.76

23 27

18.99

23 55

19.22

23 82

49.8

22 92

18.70

23 05

18.81

23 33

19.04

23.61

19.27

23 88

49.9

22 98

18.75

23 11

18.86

23 39

19.09

23 67

19.32

23 94

50.0

23 04

18.80

23 17

18.91

23 45

19.14

23 73

19.88

24 01

50.1

23 10

18.85

23 23

18.96

23 51

19.19

23 79

19.43

24 07

50.2

23 16

18.90

23 30

19.02

23 57

19.24

23 85

19.48

24 13

50.3

23 22

18.95

23 36

19.07

23 63

19.29

23 91

19.58

24.19

50.4

23 28

19.00

23 42

19.12

23.69

19.35

23 98

19.58

24 26

50.5

23 34

19.05

23.48

19.17

23 75

19.40

24 04

19.63

24 32

50.6

23 40

19.10

23.54

19.22

23 81

19.45

24 10

19.69

24 38

50.7

23.46

19.15

23 60

19.27

23 87

19.50

24 16

19.74

24 46

50.8

23 51

19.20

23.66

19.82

23 93

19.55

24 22

19.79

24 51

50.9

23 57

19.25

23 72

19.87

23 99

19.60

24 28

19.84

24 57

51.0

23 63

19.80

23 78

19.42

24 05

19.65

24 36

19.89

24 64

51.1

23 69

19.85

23 84

19.47

24 12

19.70

24 41

19.94

24.70

51.2

23 75

19.40

23 90

19.52

24 18

19.75

24.47

20.00

24 76

51.3

23 81

19.45

23 96

19.57

24 24

19.80

24 53

20.05

24 82

51.4

23 87

19.50

24 02

19.62

24 30

19.85

24 59

20.10

24 89

51.5

23 93

19.55

24 08

19.67

24 36

19.90

24 65

20.15

24 96

51.6

23 99

19.60

24.14

19.72

24 42

19.95

24 72

20.20

25 01

51.7

24 05

19.65

24 20

19.77

24 48

20.01

24 78

20.26

25 07

51.8

24.11

19.70

24 26

19.82

24 54

20.06

24 84

20.31

25 14

51.9

24.17

19.75

24 32

19.87

24 60

20.11

24 90

20.36

25 20

52.0

24 23

19.80

24 38

19.92

24 66

20.16

24 96

20.41

25.27

52.1

24 30

19.85

24.44

19.97

24 73

20.21

25 03

20.46

25 33

52.2

24 36

19.90

24 50

20.02

24.79

20.26

25 09

90.6*

25 39

52.3

24.42

19.95

24 56

20.07

24 85

20.81

25 15

20.57

25 46

52.4

24.48

20.00

24.62

20.12

24.91

20.37

25 21

20.62

25 62

52.5

24.54

20.05

24.68

20.17

24 97

20.42

25 28

20.67

25 58

52.6

24.60

20.10

24.74

20.22

25 03

20.47

25 34

20.72

25 65

52.7

24.66

20.15

24.80

20.28

25.09

20.52

25 40

20.78

25 71

52.8

24.72

20.20

24.86

20.83

25 15

20.57

25.46

■

25 77

52.9

24.78

20.25

24.92

20.88

25 22

20.62

25.53

20.88

25 84

.XVI]

TABLE. — Continued.

WINES

223
6

21° C.

22°

C.

23°

C.

24°

C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
HEADING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

18.57

23 03

18.79

23 32

19.04

23 63

19.29

23 93

19.54

48.0

18.62

23 09

18.84

23 39

19.09

23.69

19.34

23.99

19.60

48.1

18.67

23.16

18.90

23.45

19.14

23.76

19.40

24.06

19.65

48.2

18.72

23 22

18.95

23 52

19.20

23 83

19.45

24.13

19.71

48.3

18.77

23 28

19.00

23 58

19.25

23.89

19.50

24.19

19.76

48.4

18.83

23 35

19.06

23 64

19.31

23 96

19.56

24.26

19.82

48.5

18.88

23.41

19.11

23.71

19.36

24 02

19.61

24 32

19.87

48.6

18.93

23 47

19.16

23.77

19.41

24.08

19.67

24 39

19.92

48.7

18.98

23.54

19.21

23.83

19.47

24 14

19.72

24 45

19.98

48.8

19.03

23 60

19.27

23 90

19.52

24.21

19.77

24 52

20.03

48.9

19.08

23 66

19.32

23 96

19.57

24 27

19.83

24 59

20.09

49.0

19.14

23 73

19.37

24.03

19.63

24.34

19.88

24 65

20.15

49.1

19.19

23 79

19.43

24.09

19.68

24 40

19.94

24 72

20.20

49.2

19. U

23 85

19.48

24.15

19.73

24.47

19.99

24.78

20.26

49.3

19.29

23 92

19.54

24.22

19.79

24.53

20.04

24 85

20.31

49.4

19.35

23 98

19.59

24.28

19.84

24.60

20.10

24 91

20.37

49.5

19.40

24.04

19.64

24 35

19.89

24 66

20.15

24.98

20.42

49.6

19.45

24 11

19.70

24 41

19.95

24.73

20.21

25.05

20.48

49.7

19.51

24 17

19.75

24.48

20.00

24 79

20.27

25.11

20.54

49.8

19.56

24.24

19.80

24 54

20.05

24.86

20.32

25 18

20.59

49.9

19.61

24.30

19.86

24.61

20.11

24.92

20.38

25 25

20.65

50.0

19.66

24 37

19.91

24.67

20.16

24 99

20.43

25 31

20.70

50.1

19.72

24.43

19.96

24 74

20.22

25 05

20.49

25 38

20.76

50.2

19.77

24.49

20.02

24.80

20.27

25 12

20.54

25.45

20.82

50.3

19.82

24.56

20.07

24.86

20.33

25 18

20.60

25.51

20.87

50.4

19.87

24.62

20.12

24 93

20.38

25 25

20.65

25 58

20.93

50.5

19.93

24.69

20.18

24.99

20.44

25 32

20.71

25 65

20.98

50.6

19.98

24.75

20.23

25 06

20.49

25 38

20.76

25.71

21.04

50.7

20.03

24.81

20.29

25.12

20.55

25 45

20.82

25 78

21.10

50.8

20.08

24.88

20.34

25.19

20.60

25 51

20.87

25 85

21.15

50.9

20.14

24 94

20.39

25 25

20.66

25 58

20.93

25 91

21.21

51.0

20.19

25 01

20.45

25 32

20.71

25 64

20.98

25 98

21.27

51.1

20.24

25 07

20.50

25 38

20.77

25 71

21.04

26 05

21.32

51.2

20.30

25 13

20.55

25 45

20.82

25 78

21.09

26 11

21.38

51.3

20.35

25.20

20.61

25 51

20.87

25 84

21.15

26 18

21. U

51.4

20.40

25 26

20.66

25 58

20.93

25 91

21.21

26 25

21.49

51.5

20.46

25 33

20.72

25 64

20.98

25 97

21.26

26 32

21.55

51.6

20.51

25 39

20.77

25 71

21.04

26 04

21.32

26 39

21.61

51.7

20.56

25 46

20.82

25 77

21.09

26 11

21.37

26 45

21.66

51.8

20.61

25 52

20.88

25.84

21.15

26.17

21.43

26 52

21.72

51.9

20.67

25 58

20.93

25 90

21.20

26 24

21.49

26 59

21.78

52.0

20.72

25 65

20.98

25 97

21.26

26 31

21.54

26 66

21.83

52 1

20.77

25 71

21.04

26 03

21.31

26 37

21.60

26 72

21.89

20.83

25 78

21.09

26 10

21.37

26.44

21.65

26 79

21.95

52.3

20.88

25.84

21.15

26 16

21.42

26 51

21.71

26 86

M.01

52 . 1

20.93

25 90

21.20

26 23

21.48

26 57

21.77

26 93

22.06

20.98

25.97

21.26

26 29

21.63

26 64

B1.82

26 99

.' S / .'

52 6

21.04

26 03

21.31

26.36

21.59

26 71

21.88

27 06

22.18

52 . 7

21.09

26 10

21.36

26.42

21.64

26 77

21.93

27 13

22.24

52.8

21.15

26.16

21.42

26.49

21.70

26 84

21.99

27 20

22.29

52 9

224
6

METHODS OF ANALYSIS

Chap.

Table 17. — Alcohol

17.£

°C.

18'

O.

19'

C.

20

C.

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

53.0

24 84

20.30

24.98

20.43

25.28

20.68

25 59

20.93

25 90

53.1

24 90

20.36

25 04

20.48

25.34

20.73

25 65

20.98

25 96

53.2

24.96

20.41

25.10

20.53

25 40

20.78

25.71

21.04

26 03

53.3

25.02

20.46

25.16

20.58

25.46

20.83

25.77

21.09

26 09

53.4

25 08

20.51

25.23

20.63

25 52

20.88

25.84

21.14

26 15

53.5

25 14

20.56

25 29

20.68

25 59

20.93

25 90

21.20

26 22

53.6

25.20

20.61

25 35

20.74

25 65

20.98

25 96

21.25

26 28

53.7

25 26

20.66

25.41

20.79

25.71

21.04

26 03

21.30

26 35

53.8

25 32

20.71

25.47

20.84

25.77

21.09

26.09

21.36

26 41

53.9

25 38

20.76

25 53

20.89

25 83

21.14

26 15

21.41

26 47

54.0

25.44

20.81

25.59

20.94

25 90

21.19

26 22

21.47

26 54

54.1

25.50

20.86

25.65

20.99

25.96

21.25

26 28

21.52

26 60

54.2

25 56

20.91

25 71

21.04

26 02

21.30

26 34

21.57

26 67

54.3

25 62

20.96

25 77

21.09

26 08

21.35

26 41

21.63

26 73

54.4

25 68

21.02

25 84

21.14

26.14

21.40

26 47

21.68

26 79

54.5

25 75

21.07

25.90

21.20

26 20

21.46

26 53

21.73

26 86

54.6

25 81

21.12

25 96

21.25

26 27

21.51

26 59

21.79

26 92

54.7

25 87

21.17

26 02

21.30

26 33

21.56

26 66

21.84

26 99

54.8

25 93

21.22

26 08

21.35

26 39

21.62

26.72

21.90

27 05

54.9

25 99

21.27

26.14

21.40

26.45

21.67

26.78

21.95

27.11

55.0

26 05

21.32

26 20

21.45

26.52

21.72

26 85

22.00

27 18

55.1

26.11

21.37

26.26

21.51

26 58

21.77

26 91

22.05

27 24

55.2

26.17

21.43

26 32

21.56

26 64

21.83

26.97

22.11

27 31

55.3

26 23

21.48

26.38

21.61

26 70

21.88

27.04

22.16

27 37

55.4

26.29

21.53

26 45

21.66

26.76

21.93

27.10

22.21

27 43

55.5

26 35

21.58

26 51

21.71

26 83

21.98

27.16

22.26

27 49

55.6

26 41

21.63

26 57

21.76

26 89

22.04

27 23

22.32

27 55

55.7

26.47

21.68

26 63

21.81

26 95

22.09

27.29

88.87

27 62

55.8

26.53

21.73

26 69

21.87

27.01

22.14

27 35

2? 42

27.69

55.9

26.59

21.79

26.75

21.92

27 07

22.19

27.41

22.4S

27.75

56.0

26.65

21.84

26.81

21.97

27 14

22.24

27 48

22 . 53

27 82

56.1

26.72

21.89

26.87

22.02

27.20

22.30

27 54

22.58

27 88

56.2

26 78

21.94

26 93

22.07

27 26

22.35

27 60

22.64

27 94

56.3

26.84

21.99

26.99

22.12

27 32

22.40

27 66

22.69

28 01

56.4

26 90

22.04

27.05

22.18

27.38

22.45

27 73

88.74

28 07

56.5

26 96

22.09

27.12

22.23

27.44

22.50

27 79

88.79

28 14

56.6

27.02

22.14

27 18

22.28

27.51

22.56

27.85

22.85

28 20

56.7

27 08

22.19

27.24

22.33

27.57

22.61

27 91

22.90

28 26

56.8

27.14

22.25

27.30

22.38

27 63

22.66

27 98

22.95

28 33

56.9

27 20

22.30

27.36

22.43

27.69

22.71

28.04

88.01

28 39

57.0

27.26

22.35

27.42

22.48

27.75

22.77

28.10

23.06

28 46

57.1

27 32

22.40

27 48

22.54

27.81

88 82

28.16

23.11

28 52

57.2

27 38

22.45

27 54

22.59

27 88

28 23

23.17

28 59

57.3

27.44

22.50

27 60

22.64

27 94

88.98

28 29

88 22

28 65

57.4

27 50

22.55

27 66

22.69

28 00

22.97

28 35

23.27

28 72

57.5

27 56

22.61

27.73

22.74

28 06

23.03

28 42

23.33

28 78

57.6

27 62

22.66

27 79

22.79

28.13

88.08

28 48

8 J - 88

28 85

57.7

27 68

22.71

27 85

22.85

28 19

98.18

28 54

:: .:-:

28 91

57.8

27.75

22.76

27 91

22.90

28 25

23.19

28 60

23.49

28 97

57.9

27 81

22.81

27 97

22.95

28 31

28.67

23.54

29.04

XVI]

TABLE. — Continued.

WINES

225
6

21° C.

Per cent
by

weight

21.20
21.25
21 . 31
21.86
21.42

21.47
21.52
21.58
21.63
21.69

21.74
21.79
21 . 85
21 . 90
21.96

22.01
22.06
22.12
22.17

22 . 39
22.44
22.49

22.55
22.60
22.66
22.71
22.76

22.87
22.92
22.98

23.09
28.14
28.20
23.25
28.31

28.86
28.42

28.47
28.52
28 r,y.

28.63
28.69
28.74
28.80
28.85

22° C.

Per cent
by

volume

Per cent

by
weight

26 23
26 29
26 35

26 42
26.48

26 55
26 61
26 68
26 74
26.81

26 87

26 94

27 00
27 07
27 13

27 20
27 26
27 33
27 39
27 46

27 52
27 59
27 65
27 72
27 78

27 85
27 92

27 98

28 05
28.11

28 18
28 24
28 31
28 37
28 44

28 50
28 56
28 63
28 69
28 76

28 82
28 89

28 95

29 02
29 08

29 15
29 21
29 28
29 34
29 41

21.47
21.53
21.58
21.64
21.69

21.74
21.80
21.85
21.91
21.96

22.07
22.18
22.18
22.24

22.40
22.46
22.51

22.57
22.68
22.68
22.74
22.79

22.85
22.90
22.96
23.01
23.07

23.18
23.23
23.29
23.34

23.40
28.45
23.51
23.56
23.62

23.67
23.73
23.78
23.84
23.90

23.95
24.01
24.06
24.12
24.17

23° C.

Per cent

by
volume

Per cent

by
weight

26 56
26 62
26 69
26 75
26 82

26 88

26 95

27 01
27 08
27 15

27 21
27 28
27 35
27.41
27.48

27 55
27 61
27 68
27.75
27 81

27 88

27 95

28 01
28 08

28 15

28 21
28 28
28 34
28 41
28 48

28 54
28 61
28 68
28 74
28 81

28 87

28 94

29 01
29 07
29.14

29 20
29 27
29 34
29 40
29.47

29 53
29 60
29 66
29 73
29 80

21.75
21.81
21.86
21.92
21.97

22.03
22.08
22.14
22.20
22.25

22.37
22.42
22.48
22.53

22.59
22.65
22.70
22.76
22.81

22.87
22.93
22.98
23.04
23.10

23.15
28.21
23.26
28.32
23.88

23.43
23.49
28.54
23.60
23.66

28.71
28.77
28.88
28.88
23.94

28.99
24-05
24.11
24.16
24.22

24.27
24.88
24.39
U.44
24.50

24° C.

Per cent
by

volume

Per cent

by
weight

26.91

26 97
27.04
27.11
27.17

27 24
27.31
27.38
27.44
27.51

27 58
27 64
27 71
27 78
27.85

27 91

27 98

28 05
28.11
28.18

28 25
28 32
28 38
28 45
28.52

28 58
28 65
28.72
28.78
28.85

28 92

28 99

29 05
29 12
29 19

29 26
29 32
29 39
29 46
29 53

29 59
29 66
29 73
29 80
29 86

29 93

30 00
30 07
30 14
30.20

22.05
22.10
22.16

22.22
22.27

22.83
22.39
22.U
22.50
22.56

22.61
22.67
22.73
22.78
22.84

22.90
22.95
23.01
23.07
23.13

23.18
23.24
28.30
23.35
28.41

23.47
23.58
23.58
23.64
23.70

23.75
23.81
23.87
28.98
23.98

24M
24.10
24.15
24.21
24.27

24.82
24.38

u.u

24.49
24.55

24. 61
24.66

24.72
24.78
24.83

25° C.

Per cent

by
volume

Per cent

by
weight

27.27
27.33
27.40
27.47
27.64

27.61
27.67
27.74
27.81
27.88

27 95

28 01
28 08
28 15
28 22

28 29
28 36
28.43
28.49
28 56

28 63
28 70
28.77
28 84
28 90

28 97

29 04
29 11
29 18

29 24

29 31
29 38
29 45
29 52
29 58

29 65
29 72
29.79
29 86
29 93

29 99

30 06
30 13
30 20
30 27

30 34
30 41
30 48
30.55
30 62

22.35
22.41
22.47
22.52
22.58

22.64
22.70
22.75
22.81
22.87

22.93
22.98
28.04
23.10
23.16

28.27
28.83
28.39
23.45

23.51
23.56
23.62
23.68
23.74

23.80
23.86
23.91
23.97
24.03

24.09
24.14
24.20
24.26
24.32

24.88
24.43
24.49
24 . 55
24. 61

24.66
24.72
24.78
24.84
24-90

24.95
25.01
25.07
25.18
25.19

SCALE
READING

53.0
53.1
53.2
53.3
53.4

53.5
53.6
53.7
53.8
53.9

54.0
54.1
54.2
54.3
54.4

54.5
54.6
54.7
54.8
54.9

55.0
55.1
55.2
55.3
55.4

55.5
55.6
55.7
55.8
55.9

56.0
56.1
56.2
56.3
56.4

56.5
56.6
56.7
56.8
56.9

57.0
57.1
55.2
55.3
57.4

57.5
57.6
57.7
57.8
57.9

226
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

■c.

18

>C.

19

C.

20

C.

21° C.

SCALE
BEADING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

byL

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

58.0

27.87

22.86

28.03

23.00

28 38

23.29

28 73

23.59

29 10

58.1

27.93

22:91

28.09

2S.05

28 44

23.34

28 79

23.65

29 17

58.2

27 99

22.96

28 15

23.10

28 50

23.40

28 86

23.70

29 23

58.3

28.05

23.02

28 21

23.16

28 56

23.45

28 92

23.75

29 29

58.4

28.11

23.07

28.28

23.21

28 62

23.50

28 98

23.81

29 36

58.5

28 17

23.12

28 34

23.26

28 69

23 56

29 04

23.86

29 42

58.6

28 23

23.17

28.40

23.31

28 75

23.61

29 11

23.91

29 48

58.7

28 29

23.22

28.46

23.36

28 81

23.66

29 17

23.97

29 55

58.8

28 35

23.27

28 52

23.41

28 88

23.71

29 23

24-02

29 61

58.9

28.41

23.32

28 58

23.47

28 94

23.77

29 30

24. 08

29 68

59.0

28 47

23.37

28 64

23.52

29 00

23.82

29 36

24.13

29 74

59.1

28 53

23.43

28.71

23.57

29 06

23.87

29 42

24. 18

29 80

59.2

28 59

23.48

28.77

23.62

29 12

23.93

29 49

24.24

29 87

59.3

28 65

23.53

28 83

23.67

29 19

23.98

29 55

24-29

29 93

59.4

28.71

23.58

28.89

23.73

29 25

24.03

29 61

24.34

29 99

59.5

28 78

23.63

28 95

23.78

29 31

24.08

29 68

24-40

30 06

59.6

28 84

23.68

29 01

23.83

29 37

24-14

29 74

24-45

30 13

59.7

28 90

23.73

29 07

23.88

29 43

24-19

29 80

24-50

30 19

59.8

28 96

23.79

29 13

23.93

29 50

24.24

29 87

24-56

30 26

59.9

29 02

23.84

29 20

23.98

29 56

24.30

29.93

24-61

30 32

60.0

29.08

23.89

29 26

24-04

29 62

24-35

29 99

24-67

30 39

60.1

29.14

23.94

29 32

24-09

29 68

24-40

30 06

24-72

30 45

60.2

29.20

23.99

29 38

24-14

29 74

24-46

30 12

24.77

30 52

60.3

29 26

24.04

29 44

24-19

29 81

24-51

30 19

24-83

30 59

60.4

29 32

24.10

29 50

24-25

29 87

24-56

30 25

24-88

30 65

60.5

29 38

24-15

29 56

24-30

29 93

24-61

30 32

24-94

30 72

60.6

29 45

24-20

29 63

24-35

29 99

24.67

30 38

24-99

30 78

60.7

29 51

24-25

29 69

24-40

30 06

24.72

30 45

25.04

30 85

60.8

29 57

24-30

29.75

24-46

30 12

24-77

30 51

25.10

30 91

60.9

29 63

24-35

29 81

24-51

30 18

24.83

30 57

25.16

30 98

61.0

29 69

24-41

29 87

24-56

30 25

24.88

30 64

25.21

31 05

61.1

29 75

24-46

29.93

24-61

30 31

24-93

30 70

25.27

31.11

61.2

29 81

24-51

29.99

24-66

30 38

24-98

30 77

25.32

31 18

61.3

29 87

24-56

30 06

24.72

30 44

25.04

30 83

25.38

31 25

61.4

29 93

24.61

30 12

24.77

30 50

25.09

30 90

25.44

31 32

61.5

29 99

24-67

30 18

24-82

30 57

25.15

30 96

25.49

31 39

61.6

30 06

24-72

30 26

24.87

30 63

25.20

31 03

25 . 55

31 45

61.7

30.12

24-77

30 31

24-93

30.69

25.26

31 09

25.60

31 52

61.8

30 18

24-82

30 37

24-98

30 76

25.31

31 16

25.66

31 59

61.9

30.25

24.88

30.44

25.03

30 82

25.37

31 23

25.71

31 66

62.0

30 31

24-93

30 50

25.09

30 89

25.43

31 29

25 . 77

31 72

62.1

30 37

24-98

30 56

2-5.14

30 95

25.48

31 36

25.83

31 79

62.2

30 43

2 .03

30 63

25.20

31 01

25.54

31 43

25.88

31 86

62.3

30.50

25.09

30 69

25.25

31 08

25.59

31 49

25.94

31 93

62.4

30 56

25.14

30 75

25.31

31 14

25.65

31 56

25.99

31 99

62.5

30 62

25.20

30 82

25.36

31 21

25.70

31 63

26.05

32 06

62.6

30 69

25.25

30 88

25.41

31 28

25.76

31 69

26.11

32 13

62.7

30.75

85.81

30 94

25.47

31 34

25.81

31 76

26.17

32 20

62.8

30 81

25.36

31.01

25.53

31 41

25.87

31 83

32 27

62.9

30 87

25.42

31 07

25.58

31 47

25.92

31 89

26.29

32 34

XVI]

Table.— Continued.

WINES

227
6

21° C.

22

'C.

23

'C.

24

'C.

25

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

23.91

29.47

24-23

29 87

24.55

30 27

24-89

30 69

25.25

58.0

23.96

29.54

24.28

29 93

24. 61

30 34

24.95

30.76

25.31

58.1

24-02

29.60

24.34

29 99

24.66

30.41

25.01

30 83

25.37

58.2

24.07

29.67

24.39

30 06

24-72

30.48

25.07

30 90

25.43

58.3

24.13

29 73

24.45

30.13

24.78

30 54

25.13

30 97

25.49

58.4

24.18

29 80

24.50

30 20

24.83

30 61

25.18

31 04

25.55

58.5

24.23

29 86

24-56

30 26

24.89

30 68

25.23

31.11

25.61

58.6

24.29

29 93

24.61

30 33

24.94

30 75

25.29

31 18

25.67

58.7

2434

29 99

24.67

30 40

25.00

30 82

25.35

31 25

25.73

58 8

24.40

30 06

24.72

30.47

25.06

30.88

25.41

31.32

25.80

58.9

24.45

30 13

24-78

30 53

25.12

30 95

25.47

31 40

25.86

59.0

2451

30 19

24-83

30 60

25.18

31.02

25.53

31.47

25.92

59.1

24.56

30 26

24.89

30 67

25.24

31 09

25.59

31 54

25.98

59.2

24. 61

30 33

24.95

30 74

25.30

31 16

25.65

31 61

26.04

59.3

24.67

30 39

25.00

30 81

25.36

31 23

25.71

31.68

26.10

59.4

24.72

30 46

25.06

30 87

25.41

31 30

25.77

31 76

26.16

59.5

24.78

30 53

25.11

30 94

25.47

31 38

25.83

31 83

26.23

59.6

24.83

30 59

25.17

31 01

25.53

31.45

25.89

31 90

26.29

59.7

24.89

30 66

25.23

31 08

25.59

31 52

25.95

31 97

26.35

59.8

24.94

30 73

25.29

31 15

25.65

31 59

26.02

32 04

26.42

59.9

24.99

30 79

25.34

31 22

25.71

31 66

26.08

32 12

26.48

60.0

25.05

30 86

25.40

31.29

25.77

31 73

26.14

32 19

26.54

60.1

25.11

30 93

25.46

31 36

25.83

31 80

26.20

32 27

26.61

60.2

25.16

30 99

25.52

31 43

25.89

31 87

26.27

32 34

26.67

60 3

25.22

31 06

25.57

31.50

25.95

31 94

26.33

32 41

26.73

60.4

25.28

31 13

25.63

31.57

26.01

32 02

26.39

32 49

26.80

60.5

25.34

31 20

25.69

31 64

26.07

32 09

26.45

32 56

26.86

60.6

25.39

31 27

25.75

31 71

26.13

32 16

26.52

32 64

26.92

60.7

25.45

31 33

25.80

31 78

26.19

32 23

26.58

32 71

26.99

60.8

25.51

31.40

25.86

31 85

26.25

32 30

26.64

32 78

27.05

60.9

25.56

31 47

25.92

31 92

26.31

32 38

26.70

32 86

27 12

61.0

25.62

31 54

25.98

31 99

26.37

32 45

26.76

32 93

27.18

61.1

25.68

31 61

26.04

32 06

26.43

32 62

26.83

33 01

27.24

61.2

25.73

31 67

26.10

32 13

26.49

32 59

26.89

33 08

27.31

61.3

25.79

31.74

26.16

32 20

26.55

32.67

26.95

33 16

27.37

61.4

25.85

31 81

26.22

32 27

26.61

32 74

27.01

33 23

27.44

61.5

25.90

31 88

26.28

32 34

26.67

32 81

27.08

33 31

27.50

61.6

25.96

31 95

26.34

32 41

26.73

32 88

27.14

33 38

27.56

61.7

26.02

32 01

26.40

32.49

26.79

32 96

27.20

33 46

27.63

61.8

26.08

32 09

26.46

32 56

26.85

33 03

27.27

33 53

27.69

61.9

26.14

32 16

26.51

32 63

26.92

33 10

27.33

33 60

27.76

62.0

26.20

32 23

26.57

32 70

26.98

33 18

27.39

33 68

27.82

62 1

26.25

32 30

26.63

32 77

27.04

33 25

27.46

33 75

27.88

62.2

26.31

32 37

26.69

32 84

27.10

33 33

27.52

33 83

27.95

62.3

26.37

32 44

26.75

32 91

27.16

33 40

27.58

33 90

28.01

62.4

26.43

32 51

26.81

32 99

27.23

33 47

27.65

33 98

28.08

62.5

26.49

32 58

26.87

33 06

27.29

33 55

27.71

34 05

28.15

62 6

26.55

32 65

26.93

33 13

27.35

33 62

27.77

34 13 i

28.22

62 :

26.61

32 72

26.99

33 20

27.41

33 70

27.84

34 21 28.28

62 8

26.67

32 79

27.06

33 28

27.48

33.77

27.90

34 29 28.35

62.9

228
6

METHODS OF ANALYSIS

Chap.

Table 17.— Alcohol

17.5

•c.

18°

C.

19'

c.

20°

C.

21° C

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

63.0

30 94

25.47

31 14

25.64

31 54

25.98

31.96

26.35

32.41

63.1

31 00

25.52

31 20

25.69

31.61

26.03

32.03

26.41

32 48

63.2

31 06

25.58

31 26

25.75

31.67

26.09

32.10

26.46

32.56

63.3

31 13

25.63

31.33

25.80

31.74

26.15

32.17

26.52

32.62

63.4

31 19

25.69

31 39

25.86

31.80

26.21

32.23

26.58

32.69

63.5

31 26

25.74

31 46

25.91

31.87

26.26

32.30

26.64

32 76

63.6

31 32

25.80

31 52

25.97

31.93

26.32

32.37

26.70

32 83

63.7

31 38

25.85

31 59

26.02

32.00

26.38

32.44

26.76

32 90

63.8

31.45

25.91

31 65

26.08

32.07

26.44

32 51

26.82

32.97

63.9

31 51

25.96

31 72

26.13

32 13

26.49

32.58

26.88

33.04

64.0

31 58

26.02

31 78

26.19

32.20

26.55

32 65

26.94

33.11

64.1

31 64

26.07

31.85

26.25

32.27

26.61

32.72

26.99

33.18

64.2

31 70

26.13

31 91

26.30

32 34

26.67

32.79

27.05

33.25

64.3

31 77

26.18

31 97

26.36

32.40

26.72

32.86

27.11

33.32

64.4

31 83

26.24

32 04

26.41

32.47

26.78

32.92

27.17

33.39

64.5

31 90

26.29

32 11

26.47

32.54

26.84

32.99

27.23

33.46

64.6

31.96

26.35

32 17

26.53

32.60

26.90

33.06

27.29

33.53

64.7

32 03

26.40

32.24

26.58

32.67

26.95

33.13

27.35

33.60

64.8

32 09

26.46

32.30

26.64

32.74

27.01

33.20

27.41

33.67

64.9

32 16

26.51

32 37

26.69

32.81

27.07

33 27

27.47

33 74

65.0

32.22

26.57

32 43

26.75

32.87

27.13

33.34

27.58

33.82

65.1

32 29

26.68

32.50

26.80

32.94

27.19

33.41

27.59

33.89

65.2

32.35

26.68

32 57

26.86

33.01

27.25

33.48

27.65

33.96

65.3

32.42

26.74

32 63

26.92

33.08

27.31

33 55

27.71

34.03

65.4

32 48

26.79

32 70

26.97

33.15

27.87

33.62

27.77

34.10

65.5

32 55

26.85

32.76

27.03

33.22

27.48

33.69

27.88

34.18

65.6

32.61

26.90

32.83

27.09

33.28

27.49

33.76

27.89

34.25

65.7

32 68

26.96

32.89

27.15

33.35

27.54

33.83

27.95

34.32

65.8

32 75

27.01

32.96

27.21

33 42

27.60

33.90

28.01

34.40

65.9

32 81

27.07

33 03

27.26

33 49

27.66

33.97

28.07

34.47

66.0

32.88

27.18

33 10

27.32

33.56

27.72

34.04

28.18

34.64

66.1

32.94

27.19

33.17

27.38

33.63

27.78

34.11

28.19

34.62

66.2

33 01

27.25

33 23

27.44

33.70

27.84

34.18

28.26

34.69

66.3

33 07

27.30

33 30

27.50

33.77

27.90

34.25

28.82

34.76

66.4

33 14

27.36

33 37

27.56

33.84

27.96

34 33

28.38

34.84

66.5

33.21

27.42

33.44

27.62

33.91

28.02

34.40

28.45

34.91

66.6

33 28

27.48

33 51

27.68

33.98

28.08

34.47

28.51

34.99

66.7

33 35

27.54

33.58

27.78

34.05

28.14

34.54

28.57

35 06

66.8

33 41

27.60

33.65

27.79

34 12

28.20

34.62

28.64

35.14

66.9

33 48

27.65

33.72

27.85

34.19

28.27

34.69

28.70

36.21

67.0

33 55

27.71

33.79

27.91

34.26

28.88

34.76

2S.76

35.29

67.1

33 62

27.77

33.86

27.97

34.34

28.39

34.83

28.82

35.37

67.2

33 69

27.88

33.92

28.08

34.41

28.45

34.91

28.89

35 44

67.3

33.76

27.89

38.99

28.09

34.48

28.52

34.98

2S.95

35.52

67.4

33 82

27.95

34.06

28.15

34.55

28.58

35.05

29.01

35.60

67.5

33 89

28.01

34.13

28.21

34.62

28.64

35.13

29.08

35.67

67.6

33 96

28.06

34.20

28.27

34.69

28.70

35.20

29.14

35.75

67.7

34.03

28.12

34 27

28.34

34.76

28.76

35.28

35.82

67.8

34 09

28.18

34 34

28.40

34.84

28.83

35.35

36.90

67.9

34 16

28.24

34.41

28.46

34.91

28.89

35.43

29.34

35.98

x^

n\

WINES

229

Table-

-Continued.

6

21° C.

22°

C.

23°

C.

24°

C.

25

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

26.73

32 87

27.12

33 35

27.54

33.84

27.96

34 36

28.42

63.0

26.79

32 94

27.18

33.42

27.60

33.92

28.03

34.44

28.49

63.1

26.85

33.01

27.24

33.50

27.66

33 99

28.09

34.52

28.55

63.2

26.91

33.08

27.31

33 57

27.72

34 07

28.16

34.60

28.62

63 3

26.96

33 .15

27.37

33 64

27.79

34.15

28.23

34.67

28.69

63.4

27.02

33.22

27.43

33.72

27.85

34 22

28.29

34.75

28.76

63.5

27.09

33 30

27.49

33.79

27.91

34 30

28.36

34 83

28.82

63.6

27.15

33 37

27.56

33.86

27.98

34.38

28.43

34.91

28.89

63.7

27.21

33 44

27.62

33 93

28.04

34.45

28.49

34 98

28.96

63.8

27.27

33 51

27.68

34 01

28.11

34 53

28.56

35.07

29.03

63.9

27.33

33 59

27.74

34.08

28.17

34.61

28.63

35 15

29.10

64.0

27.39

33 66

27.81

34 16

28.24

34 68

28.69

35 23

29.17

64.1

2745

33 73

27.87

34 23

28.30

34 76

28.76

35.31

29.24

64.2

27.51

33 80

27.93

34 31

28.37

34 84

28.83

35 39

29.31

64.3

27.57

33 88

27.99

34 39

28.43

34.92

28.89

35 48

29.38

64.4

27.63

33 95

28.06

34 46

28.50

34 99

28.96

35 56

29.45

64.5

27.70

34 02

28.12

34.54

28.57

35.07

29.03

35 64

29.52

64.6

27.76

34 10

28.19

34.61

28.63

35.15

29.10

35.72

29.60

64.7

27.82

34.17

28.25

34 69

28.70

35 23

29.17

35 80

29.67

64.8

27.88

34 24

28.31

34 76

28.76

35 31

29.24

35 89

29.74

64.9

27.94

34 32

28.38

34 84

28.83

35 39

29.31

35 97

29.81

65.0

28.00

34 39

28.44

34.92

28.89

35 47

29.38

36 05

29.88

65.1

28.06

34.47

28.51

34 99

28.96

35 55

29.44

36 13

29.95

65.2

28.13

34.54

28.57

35 07

29.03

35 63

29.51

36 21

30.02

65.3

28.19

34 61

28.63

35 15

29.10

35 71

29.58

36 30

30.10

65.4

28.25

34 69

28.70

35 23

29.16

35.79

29.65

36 38

30.17

65.5

28.32

34 76

28.76

35 30

29.23

35 87

29.72

36 46

30.24

65.6

28.38

34 84

28.83

35 38

29.30

35 94

29.79

36 55

30.32

65.7

28.45

34 91

28.89

35 46

29.37

36 02

29.86

36 63

30.39

65.8

28.51

34 99

28.96

35 54

29.44

36 11

29.93

36 71

30.46

65.9

28.67

35 06

29.02

35 62

29.51

36 19

30.00

36 79

30.54

66.0

28.64

35 14

29.09

35 70

29.58

36 27

30.07

36 88

80.61

66.1

28.70

35 22

29.16

35 77

29.64

36 35

30.15

36 96

30.68

66.2

28.76

35 30

29.23

35 85

29.71

36 43

30.22

37 04

30.76

66.3

28.83

35 38

29.29

35 93

29.78

36 52

30.29

37 13

80.83

66.4

28.89

35 45

29.36

36 01

29.85

36 60

30.36

37 22

30.90

66.5

28.96

35 53

29.43

36 09

29.92

36 68

30.43

37 30

30.98

66.6

29.03

35 61

29.50

36 17

29.99

36 76

30.51

37 39

81.05

66.7

29.09

35 69

29.57

36.25

30.06

36 84

30.58

37 48

81.18

66. S

29.15

35 77

29.64

36 33

30.13

36 93

30.65

37 57

31.21

66.9

29.22

35 84

29.71

36 41

30.20

37 01

30.72

37 65

81.28

67.0

29.29

35 92

29.77

36 49

30.27

37 09

30.80

37 74

81.86

67.1

29.35

36 00

29.84

36 57

30.34

37 18

30.87

37 83

81.44

67 2

29.42

36 08

29.91

36 65

30.41

37 26

30.94

37 91

81.51

67.3

29.49

36 16

29.98

36 73

30.49

37 35

31 .02

38 00

81.59

67.4

29.55

36 24

30.05

36 81

30.56

37.44

31.09

38 09

31.65

67.5

29.62

36 32

SO. 12

36 90

30.63

37 52

31.17

38 13

SI . 7/f

67.6

29.69

36 40

30.19

36 98

30.70

37 61

31.24

38 26

31.82

67.7

29.75

36 48

30.26

37.06

30.77

37 69

31.32

38 35

31.89

67.8

29.82

36 56

30.33

37.14

30.84

37 78

31.39

38 44

81.97

67.9

230
6

METHODS OF ANALYSIS

[Chap.

Table 17.— Alcohol

17.5

°C.

18e

C.

19°

C.

20°

C.

21° C.

SCALE
BEADING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

68.0

34.23

28.30

34.48

28.52

34 98

28.95

35 50

29.41

36 05

68.1

34.30

28.36

34.55

28.58

35 05

29.01

35 57

29.47

36 13

68.2

34.36

28.42

34.62

28.64

35 13

29.08

35 65

29.54

36 21

68.3

34.43

28.48

34 69

28.70

35 20

29.14

35 72

29.60

36 29

68.4

34.50

28.54

34.76

28.76

35.27

29.21

35 80

29.67

36 37

68.5

34.57

28.59

34 83

28.82

35 35

29.27

35 87

29.73

36 45

68.6

34 64

28.65

34.90

28.88

35.42

29.33

35 95

29.80

36 52

68.7

34 70

28.71

34.97

28.95

35 49

29.40

36 02

29.86

36 60

68.8

34.77

28.77

35.04

29.01

35 57

29.46

36 10

29.93

36 68

68.9

34.84

28.83

35 12

29.07

35 64

29.53

36.18

29.99

36 76

69.0

34 91

28.89

35 19

29.13

35 71

29.59

36 25

30.06

36 84

69.1

34 97

28.95

35 26

29.19

35 79

29.65

36 33

30.13

36 91

69.2

35 04

29.01

35 33

29.26

35 86

29.72

36 41

30.20

36 99

69.3

35 12

29.07

35 40

29.32

35 93

29.78

36.48

30.27

37 07

69.4

35 19

29.14

35 47

29.38

36 01

29.85

36.56

30.33

37.15

69.5

35 27

29.20

35 55

29.45

36 08

29.91

36.64

so.40

37 24

69.6

35 34

29.26

35 62

29.51

36 16

29.97

36 72

30.47

37 32

69.7

35 41

29.33

35 69

29.57

36 23

30.04

36 79

30.54

37 40

69.8

35 49

29.39

35 76

29.64

36 31

30.11

36 87

30.61

37 48

69.9

35 56

29.46

35 83

29.70

36 39

30.17

36 95

30.67

37 56

70.0

35 64

29.52

35 91

29.76

36 46

30.24

37.02

30.74

37 64

70.1

35 71

29.59

35 98

29.82

36 54

30.31

37.10

30.81

37 72

70.2

35 78

29.65

36 05

29.89

36 61

30.38

37 19

30.88

37 80

70.3

35.86

29.72

36.13

29.95

36 69

30.44

37 27

30.95

37 89

70.4

35.93

29.78

36 20

30.01

36 76

30.51

37 35

31.01

37 97

70.5

36 01

29.85

36 28

30.08

36 84

30.58

37 43

31.09

38 05

70.6

36 08

29.91

36 35

30.15

36 92

30.64

37 51

31.16

38 13

70.7

36 16

29.97

36 43

30.21

36 99

30.71

37 59

31.23

38 22

70.8

36 23

30.04

36.50

30.28

37 07

30.78

37 67

31.30

38 30

70.9

36 31

30.11

36 58

30.35

37 15

30.85

37 75

31.37

38 38

71.0

36.38

30.17

36 65

30.41

37 23

30.91

37 83

31.44

38 47

71.1

36 46

30.24

36 73

30.48

37 31

30.98

37 91

31.51

38 55

71.2

36 53

30.30

36 80

30.55

37.39

31.05

37 99

31.59

38 63

71.3

36 60

30.37

36.88

30.61

37.47

31.12

38 07

31.66

38 72

71.4

36 68

30.44

36 95

30.68

37.65

31.19

38 16

31.73

38 80

71.5

36 75

SO. 50

37 03

30.75

37 63

31.26

38 24

31.80

38 88

71.6

36 83

30.57

37 11

30.81

37.71

31.33

38 32

31.87

38 97

71.7

36 90

30.64

37.19

30.88

37.79

31.40

38 40

31.94

39 05

71.8

36 98

30.70

37 27

30.95

37 87

31.47

38 49

32.01

39 14

71.9

37 05

30.77

37 34

31.01

37 94

31.54

38 57

32.09

39 23

72.0

37 13

30.84

37 42

31.08

38 02

31.61

38 65

32.17

39 31

72.1

37 21

30.90

37 50

31.15

38 11

SI. 68

38 74

as 94

39 40

72.2

37.29

30.97

37.58

31.22

38 19

31.75

38 82

S8 Si

39 49

72.3

37 36

31.03

37 66

31.29

38 27

SI 82

38 90

32.39

39 57

72.4

37.44

31.10

37 73

31.36

38 35

31.89

38 98

39 66

72.5

37.52

31.17

37.81

31.42

38.43

31.96

39 07

39 75

72.6

37.60

31.24

37 89

31 . 49

38 51

32.04

39 16

S8.6M

39 83

72.7

37 67

31.31

37 97

31.56

38 59

32.11

39 24

39 92

72.8

37.75

31.37

38 05

31.63

38 67

32.18

39 33

■ : ::

40 01

72.9

37 83

31.44

38 13

31.70

38 76

■>\\ ?•;

39 41

40 10

XVI]

TABLE. — Continued.

WINES

231
6

21° C.

22°

C.

23°

C.

24°

C.

25°

C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE
READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

29.89

36 63

so. 40

37 23

80.91

37 86

81.47

38 53

32.05

68.0

29.95

36 71

30.47

37 31

30.99

37 95

81.54

38 61

32.13

68.1

30.02

36 79

30.54

37 39

31.06

38 03

31.62

38.70

32.21

68.2

30.09

36 87

30.61

37 48

SI. IS

38.12

31.69

38.79

32.29

68.3

30.16

36 95

80.68

37 56

31.21

38.21

31.77

38 88

82.87

68.4

30.23

37 03

30.75

37 65

31.28

38 30

31.84

38 96

32.45

68.5

30.30

37 12

30.82

37 73

81. 35

38 38

31.92

39 06

32.53

68.6

30.37

37 20

80.89

37 82

81.48

38 47

31.99

39.15

32.61

68.7

SO. A3

37 28

80.96

37 90

81.50

38 56

32.07

39 24

32.69

68.8

30.50

37 36

81.08

37 98

81.57

38 64

32.15

39 33

32.77

68.9

30.57

37 45

81.10

38 07

81.65

38 73

32.23

39 43

32.86

69.0

SO. 6 A

37 53

31.17

38 15

81.72

38.82

32.81

39 52

32.94

69.1

30.71

37 61

31.25

38 24

SI. 79

38 90

32.39

39 61

33.02

69.2

SO. 7 8

37 69

81. 82

38 32

SI. 87

38 99

82.47

39.70

88.10

69.3

80.85

37.78

31.39

38.41

81.94

39 08

32.55

39 80

8S.18

69.4

30.92

37 86

SI. 46

38 50

32.02

39 17

32.63

39 89

83.26

69.5

30.99

37 94

SI. 54

38 58

82.09

39 26

32.71

39 98

83.84

69.6

31 .06

38 03

31.61

38 67

82.17

39 35

32.78

40.07

33.43

69.7

31 . 13

38.11

31.68

38 75

82.25

39.45

32.86

40.17

88.51

69.8

31.20

38 19

SI. 75

38 84

32. S3

39 54

32.95

40 26

33.59

69.9

31.27

38 28

S1.8S

38 92

32.41

39 63

33.02

40 35

83.67

70.0

31.35

38 36

31.90

39 01

82.49

39 72

S3. 11

40 44

33.75

70.1

31 .42

38 45

SI. 97

39 10

32.57

39.81

33.19

40 53

33.84

70.2

81 49

38 53

82.05

39 19

32.65

39 90

83.27

40 62

88.92

70.3

31.56

38 61

82.12

39.28

32.72

39.99

33.35

40.72

84-00

70.4

31.68

38 70

82.20

39 37

82.80

40 08

S3. 43

40 81

34.08

70.5

81.70

38 78

82.28

39 46

82.88

40 17

33.51

40 90

34.17

70.6

81.78

38 87

82 . 86

39 55

82.96

40 26

88.59

40 99

84.25

70.7

81.85

38 95

82.43

39 64

33.04

40 35

33.68

41 08

84.83

70.8

81.92

39 04

32.51

39 73

38.12

40.45

33.76

41.18

34. 4^

70.9

81 .99

39 12

32.59

39 82

88.20

40 54

33.84

41 27

34.50

71.0

82.07

39 21

32.67

39 91

88.28

40 63

33.92

41 36

84.58

71.1

82.15

39 30

32.74

40 00

88.86

40 72

34.00

41.46

8467

71.2

82.22

39 39

32.82

40 09

S3. 44

40 81

3408

41 55

84.75

71.3

82.30

39 48

32.90

40 18

S3. 52

40 90

34.17

41 64

34-88

71.4

82.87

39 57

32.98

40 27

33.60

40 99

34.25

41 74

84-92

71.5

82.45

39 65

38.05

40 36

33.68

41 08

34. S3

41.83

35.00

71.6

82.58

39 74

33.13

40 45

83.76

41.18

34.41

41 93

85.08

71.7

82.60

39 83

88.21

40 54

88.84

41.27

34.50

42 02

85.17

71.8

82.68

39 92

83.29

40 63

33.92

41 36

34.58

42.11

85.25

71.9

82.76

40 01

SS.S7

40 72

34.00

41 45

34.66

42 21

85.34

72.0

82 . 88

40 10

88.45

40 81

84.08

41 55

84-74

42 30

85.42

72.1

82.91

40.18

83.52

40 90

84.16

41 64

34-83

42 40

85.51

72.2

82.98

40 27

33.60

40 99

84.24

41.73

34-91

42 49

85.59

72.3

38.06

40 36

33.68

41 08

34.88

41.82

34.99

42 58

35.68

72.4

88.14

40 45

3S.76

41.17

84-41

41 92

35.08

42 68

85.76

72.5

88.22

40 54

33.84

41.26

84.49

42 01

35.16

42 77

85.85

72.6

88.29

40 62

38.91

41 35

84.57

42 10

35.24

42 87

85.98

72.7

83.37

40 71

38.99

41 45

84.65

42 19

96. S3

42 96

36 <)?

72.8

38.45

40 80

84.07

41.54

84.78

42 29

35.41

43 06

36.10

72.9

232

METHODS OF ANALYSIS

[Chap.

6

Table 17. — Alcohol

17.5

°C.

18°

C.

19°

C.

20°

C.

21°C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

73.0

37 91

31.51

38 21

81.77

38 84

82.33

39 50

32.92

40 18

73.1

37 98

31.58

38 29

31.84

38 92

32.40

39 59

82.99

40 27

73.2

38.06

31.65

38 37

81.90

39 00

82.48

39 67

88.07

40 36

73.3

38 14

31.71

38 45

31.97

39 08

82.55

39 76

33.15

40.44

73.4

38 22

31.78

38 53

82.04

39 17

32.62

39 84

83.22

40 53

73.5

38 30

31.85

38 61

82.12

39 25

82.70

39 93

83.30

40 62

73.6

38 38

31.92

38 69

82.19

39.34

82.77

40 02

33.37

40.70

73.7

38.46

31.99

38 77

82.26

39 42

32.85

40 10

38.45

40.79

73.8

38 54

32.06

38 85

82.34

39 50

32.92

40 19

83.53

40 88

73.9

38.62

32.13

38 93

32.41

39 59

32.99

40.28

33.60

40.97

74.0

38 70

32.20

39 01

32.48

39 67

83.07

40 36

38.68

41 05

74.1

38.78

32.27

39.09

32.55

39 76

83.15

40 46

33.76

41.14

74.2

38.86

32.35

39.18

32.63

39 84

38.22

40 53

88.88

41.23

74.3

38.94

32.42

39.26

32.70

39 92

83.80

40.62

88.91

41 32

74.4

39.02

32.49

39 34

32.77

40 01

83.87

40.71

33.98

41.41

74.5

39.10

32.56

39.43

82.85

40 09

88.45

40.79

84.06

41 50

74.6

39.18

32.63

39.51

82.92

40.18

83.53

40 88

34-U

41 59

74.7

39.26

32.70

39 59

32.99

40 27

83.60

40 97

84-22

41.68

74.8

39 35

32.78

39.68

33.07

40 35

33.68

41.05

34. SO

41.77

74.9

39 43

32.85

39.76

83.15

40.44

83.76

41 14

84.88

41 86

75.0

39.51

32.92

39.84

88.22

40 53

83.88

41.23

84.46

41 95

75.1

39.60

32.99

39.93

88.80

40 61

88.91

41 32

84-54

42.04

75.2

39 68

33.07

40 01

83.87

40.70

83.98

41.41

84.61

42 13

75.3

39.76

S3. 15

40.09

88.45

40.78

84.06

41 50

84.69

42 22

75.4

39.84

33.22

40.18

83.58

40.87

84.14

41.58

84.77

42 31

75.5

39 93

S3. SO

40.27

88.60

40.96

84.22

41 67

84.85

42 40

75.6

40.01

S3. 37

40.35

83.68

41.04

84.80

41 76

84.93

42 49

75.7

40.09

33.45

40.44

88.76

41 13

84.38

41 85

85.01

42 58

75.8

40.18

33.53

40.53

33.83

41 22

34.45

41.94

35.09

42.67

75.9

40.27

33.60

40.61

83.91

41 31

84.58

42 03

85.17

42.76

76.0

40.35

S3. 68

40.70

88.98

41.40

84.61

42.12

35.25

42.85

76.1

40.44

33.76

40.78

84.06

41.48

84.68

42.21

35.83

42 95

76.2

40.53

SS.8S

40 87

84.14

41.57

34.77

42 30

35.41

43 04

76.3

40.61

33.91

40.96

84.22

41.66

84M

42 39

35.50

43.13

76.4

40.70

S3. 98

41.04

84.29

41.75

84.92

42.48

35.58

43 22

76.5

40.78

84.06

41.13

84.87

41.83

85.00

42.57

35.66

43.32

76.6

40.87

84.U

41 22

84.45

41.92

35.08

42.66

85.74

43.41

76.7

40.96

S4.22

41.30

84.58

42.01

35.16

42.75

85.82

43 50

76.8

41.04

34-29

41.39

84.60

42.10

85.24

42 84

85.90

43 60

76.9

41.13

84.87

41 48

34.68

42.19

85.82

42 93

85.98

43 69

77.0

41.22

34.45

4187

84.76

42.28

85.40

43.02

86.07

43 79

77.1

41.31

84.52

41.65

34.84

42 37

85.48

43.11

86.15

43.88

77.2

41.39

84.60

41.74

84.91

42.46

35.56

43 20

86.24

43 97

77.3

41.48

84.68

41.83

84.99

42.54

85.64

43 30

16.32

44.07

77.4

41.57

84.75

41.91

85.07

42.63

85.72

43.39

S6.4O

44.16

77.5

41.66

84.88

42.00

85.15

42.72

85.80

43 48

S6.49

44 26

77.6

41.75

84.91

42.09

35.28

42.81

85.88

43 57

86.57

44.35

77.7

41.83

84.98

42.17

35.80

42 90

35.96

43.67

86.66

44.45

77.8

41.92

35.06

42.26

85.38

42.99

36.04

43.76

86.74

44 54

77.9

42.01

85.14

42.35

85.46

43.08

86.18

43.85

96. 8*

44.64

XVI]

Table. — Continued.

WINES

233
6

21° C.

22

'C.

23

'C.

24

C.

25

'C.

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

SCALE

READING

by

by

by

by

by

by

by

by

by

weight

volume

weight

volume

weight

volume

weight

volume

weight

S3. 52

40 88

34.15

41.63

34.81

42.38

35.49

43.15

36.18

73.0

33.60

40.97

34.23

41.72

34.89

42.47

35.58

43.24

36.27

73.1

33.68

41.06

34.31

41 81

34-98

42.56

35.66

43 33

36.35

73.2

33.75

41.15

34.39

41 90

35.06

42.66

35.74

43.43

36.43

73.3

33.83

41.24

34.47

41.99

35.14

42.75

35.83

43 52

36.52

73.4

33.91

41 33

34.55

42.08

35.22

42.84

35.91

43 61

36.60

73.5

33.98

41.42

34.63

42.17

35.31

42.93

35.99

43.70

36.68

73.6

34-06

41.51

34.71

42.27

35.39

43 03

36.08

43 80

36.77

73.7

S4.U

41.60

34.79

42 36

35.47

43 12

36.16

43.89

36.85

73.8

34.22

41.69

34.87

42.45

35.55

43.21

36.24

43 98

36.93

73.9

34-30

41.78

34.95

42.54

35.64

43 31

36.33

44 08

37.02

74.0

34.38

41.87

35.03

42 63

35.72

43 40

36. 41

44.18

37.11

74.1

34.46

41.96

35.12

42 72

35.80

43 49

36.49

44.28

37.20

74.2

34.54

42.06

35.20

42.82

35.88

43.58

36.58

44.38

37.29

74.3

34.62

42.15

35.28

42 91

35.97

43 68

36.66

44.48

37.38

74.4

34.70

42.24

35.36

43 00

36.05

43.77

36.74

44.57

37.47

74.5

34.78

42.33

35.45

43 09

36.13

43.86

36.83

44 67

37.56

74.6

34.86

42.42

35.53

43 19

36.22

43.95

36.91

44.77

37.65

74.7

34.94

42.51

35.61

43.28

36.30

44.05

36.99

44.87

37.75

74.8

35.02

42.61

35.69

43 37

36.39

44.15

37.08

44.97

37.84

74.9

35.10

42.70

35.78

43.46

36. 47

44.25

37.17

45 07

37.93

75.0

35.18

42 79

35.86

43.56

36.55

44.34

37.26

45.18

38.02

75.1

35.26

42.88

35.95

43 65

36.64

44.44

37.35

45.29

38.12

75.2

35.34

42 97

36.03

43.74

36.72

44.53

37.44

45.39

38.21

75.3

35.43

43 07

36.11

43.83

36.81

44.63

37.53

45.50

38.31

75.4

35.51

43.16

36.20

43.92

36.89

44.73

37.62

45 61

38.40

75.5

35.59

43.25

36.28

44.02

36.97

44.83

37.71

45.71

88.50

75.6

35.67

43.35

36.36

44.12

37.06

44.93

37.80

45 82

88.60

75.7

35.75

43.44

36. 45

44.21

37.15

45.03

37.89

45 92

88.69

75.8

35.84

43.63

36.53

44.31

37.24

45.13

37.98

46 02

38.79

75.9

35.92

43.63

36.62

44.41

37.33

45.24

38.08

46 12

88.88

76.0

36.00

43.72

36.70

44.50

37.42

45 34

38.17

46.23

38.98

76.1

36.08

43.81

36.79

44.60

37.50

45.44

38.27

46.34

89.08

76.2

36.17

43.91

36.87

44.70

37.59

45 65

38.36

46.45

89.18

76.3

36.25

44 00

36.96

44.80

37.68

45 65

38.46

46.56

89.29

76.4

36. 3 4

44 10

37.04

44.89

37.77

45.75

38.55

46.67

89.39

76.5

36. 42

44.19

37.13

44.99

37.86

45 86

38.65

46.78

89.49

76.6

36.51

44.29

37.22

45.09

37.95

45 96

38. 74

46.89

39.59

76.7

36.59

44.38

37.30

45.19

38.04

46.07

38.84

47.00

89.69

76.8

36.68

44.48

37.39

45 30

38.13

46.18

38.93

47.11

89.80

76.9

36.76

44.57

37.47

45 40

38.23

46 29

39.03

47.23

39.90

77.0

36.85

44.67

37.56

45.50

38.32

46.40

39.13

47.34

40.00

77.1

36.93

44.76

37.65

45.60

38. 42

46 51

39.23

47 45

40.11

77.2

37.02

44.86

37.73

45.70

38.51

46.62

39.34

47.57

40.22

77.3

37.10

44.95

37.82

45.81

38.60

46.73

39.44

47.68

40.32

77.4

37.19

45.05

37.91

45.91

38.70

46.84

39.54

47.80

40.43

77.5

37.28

45.15

37.99

46.01

38.79

46 95

39.64

47.91

40.54

77.6

37.36

45 25

38.08

46 12

38.89

47.06

39.74

48.02

40.65

77.7

37.45

45.35

38.18

46 23

38.98

47.17

39.85

48 14

40.75

77.8

37.53

45.45

38.27

46.34

39.08

47.28

39.95

48.26

40.86

77.9

234
6

METHODS OF ANALYSIS

Chap.

Table 17.— Alcohol

17.5

°c.

18

C.

19°

C.

20°

C.

21° C.

SCALE
READING

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

Per cent

by

by

by

by

by

by

by

by

by

volume

weight

volume

weight

volume

weight

volume

weight

volume

78.0

42 09

35.22

42 43

85.54

43 17

36.21

43.94

86.91

44 73

78.1

42.18

85.30

42 52

35.62

43 27

36.29

44.04

36.99

44 83

78.2

42 26

35.88

42 61

35.70

43 36

36.38

44.13

37.08

44 92

78.3

42 35

35.45

42 70

85.77

43.46

86.46

44 23

87.16

45 02

78.4

42.44

35.53

42.78

35.85

43.54

36.54

44 32

37.25

45 12

78.5

42.52

85.61

42.87

85.93

43 63

36.68

44.42

87.88

45 22

78.6

42.61

85.69

42 96

86.01

43.72

86.71

44.51

87.42

45 32

78.7

42.69

85.77

43.05

86.09

43 82

36.79

44 60

37.50

45 42

78.8

42 78

35.84

43.14

36.17

43 91

36.88

44.70

37.59

45 52

78.9

42.86

85.92

43 23

36.26

44 00

36.96

44.79

87.68

45 62

79.0

42.95

86.00

43 32

86.34

44 09

37.04

44.89

87.76

45 72

79.1

43 04

86.08

43 41

36.42

44 19

87.13

44.98

87.85

45 82

79.2

43.13

86.16

43.50

36.50

44 28

37.21

45.08

37.94

45 92

79.3

43.22

86.25

43 59

86.59

44 38

37.30

45.18

88.02

46 02

79.4

43.31

86.33

43.68

86.67

44 47

87.88

45.28

88.11

46.13

79.5

43.40

36.41

43.77

86.75

44.56

87.47

45 38

88.20

46 24

79.6

43.49

86.49

43.86

86.88

44.65

87.56

45.48

88.80

46.34

79.7

43.58

86.57

43 95

86.92

44 75

87.64

45.58

88.89

46 45

79.8

43.67

86.66

44.05

87.00

44.84

87.73

45 68

88.48

46 56

79.9

43.76

86.74

44.14

87.09

44 93

87.81

45 78

88.57

46.67

80.0

43.85

36.82

44.24

37.17

45.04

37.90

45 88

S8.67

46.77

XVIJ

TABLE — Concluded.

WINES

235
6

21° C.

22

c.

23°

c.

24°

c.

25°

c.

Per cent

by
weight

Per cent
by

volume

Per cent

by
weight

Per cent

by
volume

Per cent

by
weight

Per cent

by
volume

Per cent

by
weight

Per cent

by
volume

Per cent

by
weight

READING

S7.62
37.71
S7.79
S7.88
37.97

45.56
45.66
45.76
45.86
45.96

38.37
38.46
38.56
38.65
38.75

46.45
46.56
46.67
46.78
46.89

39.18
39.29
39.39
39.49
39.59

47.40
47.51
47.63
47.74
47.85

40.05
40.16
40.27
40.37

40.48

48.37
48.49
48.60
48.72
48.84

40.97
41.08
41.18
41.29
41.40

78.0
78.1
78.2
78.3

78.4

38.06
38.15
38. U
38.33
38.43

46.07
46.17
46.28
46 39
46.50

38.84
38.93
39.03
39.13
39.23

47 00
47.11
47.22
47.34
47.46

39.69
39.80
39.90
40.00
40.11

47.97
48.08
48 19
48.31
48.42

40.59

40.69
40.80
40.90
41.01

48.95
49.07
49.19
49.31
49.42

41.51
41.62
41.73
41.84
41.95

78.5
78.6
78.7
78.8
78.9

38.52
38.61
38.70
38.80
38.89

46.61
46.72
46 83
46.93
47.04

39.33
39.43
39.54
39.64
39.74

47.66
47.67
47.79
47 90
48.01

40.21
40.32
40.42
40.53
40.68

48 63
48.65
48.76
48.88
48.99

41.12
41.22
41.33
41-44
41.54

49.54
49.66
49.77
49.89
50.01

42.05
42.16
42.27
42.88
42.49

79.0
79.1
79.2
79.3
79.4

38.98
39.08
39.18
39.28
39.38

47.15
47.26
47.37
47.48
47 69

39.84
39.94
40.04
40.14
40.24

48.12
48.23
48 34
48.46
48.67

40.74

40.84
40.95

41.05

41.16

49.10
49.22
49.33
49.45
49.56

41.65
41.76
41.86
41.97
42.08

50.13

60.24
60.36
60.48
60.59

42.60
42.71
42.82
42.98
43.04

79.5
79.6
79.7
79.8
79.9

39.48

47 70

40.35

48 68

41.26

49.68

42.18

50.71

43.15

80.0

236 METHODS OF ANALYSIS [Chap.

GLYCEROL IN DRY WINES.

7 Method I. (By Direct Weighing) — Tentative.

Evaporate 100 cc. of the wine in a porcelain dish on a water bath to a volume
of about 10 cc. and treat the residue with about 5 grams of fine sand and 4-5 cc. of
milk of lime (containing about 15% of calcium oxid) for each gram of extract pres-
ent and evaporate almost to dryness. Treat the moist residue with 50 cc. of 90%
alcohol by volume, remove the substance adhering to the sides of the dish with a
spatula and rub the whole mass to a paste. Heat the mixture on a water bath,
with constant stirring, to incipient boiling and decant the liquid through a filter
into a small flask. Wash the residue repeatedly by decantation with 10 cc. portions
of hot 90% alcohol until the filtrate amounts to about 150 cc. Evaporate the filtrate
to a sirupy consistency in a porcelain dish on a hot, but not boiling, water bath;
transfer the residue to a small, glass-stoppered, graduated cylinder with 20 cc. of
absolute alcohol and add 3 portions of 10 cc. each of anhydrous ether, shaking
thoroughly after each addition. Let stand until clear, then pour off through a
filter, and wash the cylinder and filter with a mixture of 1 part of absolute alcohol
to 1| parts of anhydrous ether, also pouring the wash liquor through the filter.
Evaporate the filtrate to a sirupy consistency, dry for an hour at the temperature
of boiling water, weigh, ignite and weigh again. The loss on ignition gives the
weight of glycerol.

8 Method II. {By Oxidation with Dichromate) — Tentative.

Evaporate 100 cc. of the wine in a porcelain dish on a water bath, the temperature
of which is maintained at 85°-90°C, to a volume of 10 cc. and treat the residue with
about 5 grams of fine sand and 5 cc. of milk of lime (containing the equivalent of
15 grams of calcium oxid). Proceed from this point as directed under XIX, 6, be-
ginning with the clause "evaporate almost to dryness, with frequent stirring".
Observe the precautions given concerning the temperature at which all evapora-
tions are to be made.

9 GLYCEROL IN SWEET WINES.— TENTATIVE.

With wines whose extract exceeds 5 grams per 100 cc, heat 100 cc. to boiling in
a flask and treat with successive small portions of milk of lime until the wine be-
comes first darker and then lighter in color. Cool, add 200 cc. of 95% alcohol by
volume, allow the precipitate to subside, filter and wash with 95% alcohol. Treat
the combined filtrate and washings as directed in 7 or 8.

10 GLYCEROL-ALCOHOL RATIO.-TENTATIVE.

Express this ratio as x : 100, in which x is obtained by multiplying the percentage
by weight of glycerol by 100 and dividing the result by the percentage of alcohol
by weight.

EXTRACT.

11 From the Specific Gravity of the Dealcoholized Wine.— Tentatiie.

Calculate the specific gravity of the dealcoholized wine by the following formula:

S = G + 1 - A in which

S = specific gravity of the dealcoholized wine;
G = specific gravity of the wine, 3; and

A = specific gravity of the distillate obtained in the determination of alco-
hol, 4 (a).

XVI] wines 237

From IX, 9, ascertain the per cent by weight of extract in the dealcoholized wine
corresponding to the value of S. Multiply the figure thus obtained by the value of
S to obtain the grams of extract per 100 cc. of wine.

"12 By Evaporation. — Tentative.

(a) In dry wines, having an extract content of less than 3 grams per 100 cc. — Evapo-
rate 50 cc. of the sample on a water bath to a sirupy consistency in a 75 cc. fiat-
bottomed platinum dish, approximately 85 mm. in diameter. Heat the residue
for 2\ hours in a drying oven at the temperature of boiling water, cool in a desicca-
tor and weigh as soon as the dish and contents reach room temperature.

(b) In sweet wines. — When the extract content is between 3 and 6 grams per 100 cc,
treat 25 cc. of the sample as directed under (a).

When the extract exceeds 6 grams per 100 cc, however, the result, obtained as
directed under 11, is accepted and no gravimetric determination is attempted.
This is because of the serious error connected with drying levulose at high tempera-
ture.

13 NON-SUGAR SOLIDS.-TENTATIVE.

Determine the non-sugar solids (sugar-free extract) by subtracting the amount
of reducing sugars before inversion, 14, from the extract, 11 or 12. If sucrose is
present in the wine, determine the non-sugar solids by subtracting the sum of re-
ducing sugars before inversion and the sucrose from the extract.

14 REDUCING SUGARS.— TENTATIVE.

(a) Dry wines. — Place 200 cc. of the wine in a porcelain dish, exactly neutralize
with N/1 sodium hydroxid, calculating the amount required from the determina-
tion of acidity, 25, and evaporate to about one fourth the original volume. Trans-
fer to a 200 cc. flask, add sufficient neutral lead acetate solution to clarify, dilute
to the mark with water, shake and filter through a folded filter. Remove the lead
with dry potassium oxalate and determine reducing sugars as directed under VIII,

25.

(b) Sweet wines. — In the case of sweet wines approximate the sugar content
by subtracting 2 from the result in the determination of the extract and employ
such a quantity of the sample that the aliquot taken for the copper reduction shall
not exceed 245 mg. of invert sugar. Proceed as directed in (a) except that this smaller
quantity of the sample is taken for the determination.

SUCROSE.

1 5 By Reducing Sugars Before and After Inversion. — Tentative.

Proceed as directed under VIII, 18, using the method given under VIII, 25, for
the determination of reducing sugars.

16 By Polarization. — Tentative.

Polarize part of the filtrate, obtained in 14, before and after inversion in
a 200 mm. tube as directed under VIII, 14 or 16. In calculating the percentage
of sucrose the relation of the amount of sample contained in 100 cc. to the normal
weight must be taken into consideration.

17 COMMERCIAL GLUCOSE.— TENTATIVE.

Polarize a portion of the filtrate, obtained in 14, after inversion in a 200
mm. jacketed tube at 87°C. as directed under IX, 25. In calculating the per-

238 METHODS OF ANALYSIS [Chap.

centage of glucose the relation of the amount of sample contained in 100 cc. to the
normal weight for the instrument must be taken into consideration.

1 g ASH.— TENTATIVE.

Proceed as directed under VIII, 4, employing the residue from 50 cc. of the wine.

19 ASH-EXTRACT RATIO.— TENTATIVE.

Express results as 1 : x, in which x is the quotient obtained by dividing the
grams of extract per 100 cc. by the grams of ash per 100 cc.

20 ALKALINITY OF THE WATER-SOLUBLE ASH— TENTATIVE.

Extract the ash, obtained as directed under 18, with successive small portions
of hot water until the filtrate amounts to about 60 cc. and proceed as directed under
IX, 18. Express the alkalinity in terms of the number of cc. of N/10 acid required
to neutralize the water-soluble ash from 100 cc. of the wine.

21 ALKALINITY OF THE WATER-INSOLUBLE ASH.— TENTATIVE.

Ignite the filter and residue from 20 in the platinum dish in which the wine was
ashed, and proceed as directed under EX, 19. Express the alkalinity in terms of
the number of cc. of N/10 acid required to neutralize the water-insoluble ash from
100 cc. of the wine.

22 PHOSPHORIC ACID.— TENTATIVE.

Dissolve the ash, obtained as directed under 18, in 50 cc. of boiling nitric acid
(1 to 9), filter, wash the filter and determine phosphoric acid in the combined filtrate
and washings, as directed in I, 6 or 9. If the ash ignites without difficulty, no free
phosphoric acid need be suspected. Should there be any free acid, the ash remains
black even after repeated leaching. In such cases calcium acetate or a mixture
containing 3 parts of sodium carbonate and 1 of sodium nitrate should be added
to avoid loss of phosphoric acid before attempting to ash.

23 SULPHURIC ACID— TENTATIVE.

Precipitate directly the sulphuric acid in 50 cc. of the wine by means of barium
chlorid solution, after acidifying with a small excess of hydrochloric acid, and de-
termine the resulting barium sulphate as directed under II, 20. Allow the precipi-
tate to stand for at least 6 hours before filtering. Report as sulphur trioxid (SOs).

24 CHLORIN.— TENTATDTE.

To 100 cc. of dry wine or 50 cc. of sweet wine add sufficient sodium carbonate
to make distinctly alkaline. Evaporate to dryness, ignite at a heat not above low
redness, cool, extract the residue with hot water, acidify the water extract with
nitric acid and determine chlorin as directed under III, 15.

25 TOTAL ACIDS.— TENTATIVE.

Measure 20 cc. of the wine into a 250 cc. beaker, heat rapidly to incipient boiling
and immediately titrate with N/10 sodium hydroxid. Determine the end point with
neutral 0.05% azolitmin solution as an outside indicator. Place the indicator in
the cavities of a spot plate and spot the wine into the azolitmin solution. The end
point is reached when the color of the indicator remains unchanged by the addition
of a few drops of N/10 alkali to the wine.

XVI]

WINES

239

In the case of wines which are artificially colored and which cannot be satis-
factorily titrated in the above manner, it will be found helpful to use phenolphthalein
powder (1 part of phenolphthalein mixed with 100 parts of dry, powdered potassium
sulphate) as an indicator. Place this indicator in the cavities of a spot plate and
spot the wine into the powder. The end of the titration is indicated when the pow-
der acquires a pink tint.

Express the result in terms of tartaric acid. One cc. of N/10 sodium hydroxid
is equivalent to 0.0075 gram of tartaric acid.

VOLATILE ACIDS.

26 Method I. — Tentative.

Heat rapidly to incipient boiling 50 cc. of the wine in a 500 cc. distillation flask
and pass steam through until 15 cc. of the distillate require only 2 drops of N/10
sodium hydroxid for neutralization. The water used to generate the steam should
be boiled several minutes before connecting the steam generator with the distilla-
tion flask in order to expel carbon dioxid. Titrate rapidly with N/10 sodium hy-
droxid, using phenolphthalein as an indicator. The color should remain about 10
seconds. Express the result as acetic acid. One cc. of N/10 sodium hydroxid is
equivalent to 0.0060 gram of acetic acid.

27

Method II. (Hortvet Method3) — Tentative.

FIG. 8. APPARATUS FOR THE DETERMINATION OF VOLATILE ACIDS.

Introduce 10 cc. of the wine, previously freed from carbon dioxid, into the inner
tube of a modified Sellier distillation apparatus (Fig. 8), add a small piece of paraf-
fin to prevent foaming, and adjust the tube and its contents in place within the larger
flask containing 100 cc. of recently boiled water. Connect with a condenser as il-
lustrated in Fig. 8 and distil by heating the outer flask. When 50 cc. of the distillate
have been collected, empty the receiver into a beaker and titrate with N/10 sodium
hydroxid, using phenolphthalein as an indicator. Continue the distillation and
titrate each succeeding 10 cc. of distillate until not more than 1 drop of standard
alkali is required to reach the neutral point. Usually 80 cc. of distillate will con-
tain all the volatile acid.

240 METHODS OF ANALYSIS [Chap.

28 FIXED ACIDS.— TENTATIVE.

Multiply the amount of volatile acids by 1.25 and subtract this from the total
acids, to obtain the amount of fixed acids, expressed as tartaric acid.

29 TOTAL TARTARIC ACID4.— TENTATIVE.

Neutralize 100 cc. of the wine with N/1 sodium hydroxid, calculating from the
acidity, 25, the number of cc. of N/1 alkali necessary for the neutralization. If the
volume of the solution is increased more than 10% by the addition of the alkali,
evaporate to approximately 100 cc. Add to the neutralized solution 0.075 gram
of tartaric acid for each cc. of N/1 alkali added and, after the tartaric acid has dis-
solved, add 2 cc. of glacial acetic acid and 15 grams of potassium chlorid. After
the potassium chlorid has dissolved, add 15 cc. of 95% alcohol by volume, stir
vigorously until the potassium bitartrate starts to precipitate, and then let stand
in an ice box for at least 15 hours. Decant the liquid from the separated potassium
bitartrate on a Gooch, prepared with a very thin film of asbestos, or on filter paper
in a Buchner funnel. Wash the precipitate and filter 3 times with a few cc. of a
mixture of 15 grams of potassium chlorid, 20 cc. of 95% alcohol by volume and 100
cc. of water, using not more than 20 cc. of the wash solution in all. Transfer the
asbestos or paper and precipitate to the beaker in which the precipitation was
made, wash out the Gooch or Buchner funnel with hot water, using about 50 cc. in
all, heat to boiling and titrate the hot solution with N/10 sodium hydroxid, using
phenolphthalein as an indicator. Increase the number of cc. of N/10 alkali re-
quired by 1.5 cc. to allow for the solubility of the precipitate. One cc. of N/10 alkali
is equivalent, under these conditions, to 0.015 gram of tartaric acid. Subtract the
amount of tartaric acid added from this result to obtain the grams of total tartaric
acid per 100 cc. of the wine.

30 FREE TARTARIC ACID AND CREAM OF TARTAR5.— TENTATIVE.
Calculate the free tartaric acid and cream of tartar in the following manner:

Let A = total tartaric acid in 100 cc. of wine divided by 0.015;
B = total alkalinity of the ash (sum of C and D);
C = alkalinity of water-soluble ash;
D = alkalinity of water-insoluble ash.
Then

(1) If A is greater than B,

Cream of tartar = 0.0188 X C; and
Free tartaric acid = 0.015 X (A-B).

(2) If A equals B or is smaller than B but greater than C,

Cream of tartar = 0.0188 X C; and
Free tartaric acid = 0.

(3) If A is smaller than C,

Cream of tartar = 0.0188 X A; and
Free tartaric acid = 0.

31

TANNIN AND COLORING MATTER— OFFICIAL.

REAGENTS.

(a) N/10 oxalic acid.— One cc. is equivalent to 0.004157 gram of tannin.

(b) Standard potassium permanganate solution. — Dissolve 1.333 grams of potas-
sium permanganate in 1 liter of water and standardize the solution against (a).

XVI] wines 241

(C) Indigo solution. — Dissolve 6 grams of sodium sulphindigotate in 500 cc. of
water by heating; cool, add 50 cc. of concentrated sulphuric acid, make up to 1
liter and filter.

(d) Purified boneblackc' . — Boil 100 grams of finely powdered boneblack with suc-
cessive portions of hydrochloric acid (1 to 3), filter and wash with boiling water until
free from chlorin. Keep covered with water.

32 DETERMINATION7.

Dealcoholize 100 cc. of the wine by evaporation and dilute with water to the
original volume. Transfer 10 cc. to a 2 liter porcelain dish; add about a liter of
water and exactly 20 cc. of the indigo solution. Add the standard potassium
permanganate solution, 1 cc. at a time, until the blue color changes to green; then add
a few drops at a time until the color becomes golden yellow. Designate the number
of cc. of permanganate solution used as "a".

Treat 10 cc. of the dealcoholized wine, prepared as above, with boneblack for
15 minutes; filter and wash the boneblack thoroughly with water. Add a liter of
water and 20 cc. of the indigo solution and titrate with permanganate as above.
Designate the number of cc. of permanganate used as "b".

Then a — b = c, the number of cc. of the permanganate solution required for the
oxidation of the tannin and coloring matter in 10 cc. of the wine.

33 CRUDE PROTEIN.— TENTATIVE.

Determine nitrogen in 50 cc. of the wine, as directed under I, 18, 21 or 23, and

multiply the result by 6.25.

34 PENTOSANS.-TENTATIVE.

Proceed as directed in VIII, 64, except that 100 cc. of the wine and 43 cc. of hy-
drochloric acid (sp. gr. 1.19) are used in beginning the distillation. Owing to the
interference of sugars this determination can be made in dry wines only.

35 GUM AND DEXTRIN.— TENTATIVE.

Evaporate 100 cc. of the wine to about 10 cc. and add 10 cc. of 96% alcohol by
volume. If gum or dextrin be present (indicated by the formation of a voluminous
precipitate), continue the addition of alcohol, slowly and with stirring, until 100
cc. have been added. Let stand overnight, filter, and wash with 80% alcohol by
volume. Dissolve the precipitate on the paper with hot water, hydrolyze the
filtrate and washings with hydrochloric acid and proceed as directed under VIII, 60.

36 NITRATES.-TENTATIVE.

(a) White wine. — Treat a few drops of the wine in a porcelain dish with 2-3 cc.
of concentrated sulphuric acid, which contains about 0.1 gram of diphenylamin8
per 100 cc. The deep blue color formed in the presence of nitrates appears so quickly
that it is not obscured, even in sweet wine, by the blackening produced by the ac-
tion of sulphuric acid on the sugar.

(b) Red wine. — Clarify with basic lead acetate, filter, remove the excess of lead
from the filtrate with sodium sulphate, filter again and treat a few drops of this
filtrate as directed under (a).

37 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

242 METHODS OF ANALYSIS

3g PRESERVATIVES.— TENTATIVE.

Proceed as directed under X.

The detection of added boric acid is somewhat difficult because a small amount
of it is normally present in certain wines. Therefore, a quantitative determina-
tion should be made. The determination of sulphurous acid must also be quanti-
tative. A small amount of salicylic acid is also normal in wine, and for that reason
not more than 50 cc. of the sample should be used in testing for that preservative.

BIBLIOGRAPHY.

1 U. S. Bur. Standards Bull. 9, No. 3. (Reprint 197).

2 J. Russ. Phys. Chem. Soc, 1908, 40: 107.
s J. lnd. Eng. Chem., 1909, 1: 31.

* U. S. Bur. Chem. Bull. 162, p. 72.

s Ibid., p. 75.

6U. S. P., VIII, 1907, p. 89.

7 Ann. Oenologie, 1871-72, 2: 1.

8 Arch. Hyg., 1884, 2: 273.

XVII. DISTILLED LIQUORS.

1 SPECIFIC GRAVITY.— TENTATIVE.

20°C
Determine the specific gravity at -p— '- by means of a pycnometer or a small,

accurately graduated hydrometer.

2 ALCOHOL BY WEIGHT.-OFFICIAL.

Weigh 20-25 grams of the sample into a distillation flask, dilute with 100 cc. of
water, distil nearly 100 cc. and weigh the distillate or make to volume at 20°C. and
in either case, determine the specific gravity as directed under 1 . Obtain the corre-
sponding percentage of alcohol by weight from XVI, 5, multiply this figure by the
weight of the distillate, and divide by the weight of the sample taken to obtain the
per cent of alcohol by weight.

The alcohol content of the distillate may be checked by determining the immer-
sion refractometer reading and obtaining, from XVI, 6, the percentage of alcohol.

ALCOHOL BY VOLUME.

3 Method I. — Official.

From the specific gravity of the distillate, obtained under 2, ascertain the cor-
responding percentage of alcohol by volume from XVI, 5. Multiply this figure by
the volume of distillate and divide by the volume of the sample (calculated from
the specific gravity) to obtain the percentage of alcohol by volume in the original
sample.

4 Method II. — Tentative.

Measure 25 cc. of the sample at 20°C. into a distillation flask, dilute with 100
cc. of water, distil nearly 100 cc, make to volume at 20°C. and determine the spe-
cific gravity as directed in 1 . Obtain, from XVI, 5, the corresponding percentage
of alcohol by volume in the distillate. Multiply by 4 to obtain the percentage of
alcohol by volume in the original substance.

The alcohol content of the distillate may be checked by determining the immer-
sion refractometer reading and obtaining the percentage of alcohol from XVI, 6.

5 EXTRACT— OFFICIAL.

Weigh, or measure at 20°C, 100 cc. of the sample, evaporate nearly to dryness
on the water bath, then transfer to a water oven, and dry at the temperature of
boiling water for 2| hours.

6 ASH.— OFFICIAL.

Proceed as directed under VIII, 4, employing the residue from the determination
of the extract, 5.

7 ACIDITY.-TENTATIVE.

Titrate 100 cc. of the sample (or 50 cc. diluted to 100 cc. if the sample is dark)
with N/10 alkali, using phenolphthalein as an indicator. Express the result as
acetic acid; 1 cc. of N/10 alkali is equivalent to 0.00(30 gram of acetic acid.

243

244 METHODS OF ANALYSIS [Chap.

8 ESTERS.— TENTATIVE.

Measure 200 cc. of the sample into a distillation flask, add 25 cc. of water and
distil slowly 200 cc, using a mercury valve to prevent loss of alcohol. Exactly
neutralize the free acid in 50 cc. of the distillate with N/10 alkali, add a measured
excess of 25-50 cc. of N/10 alkali, and either boil for an hour under a reflux con-
denser, cool and titrate with N/10 acid, or allow the solution to stand overnight
in a stoppered flask with the excess of alkali, heat with a tube condenser for 30 min-
utes at a temperature below the boiling point, cool and titrate. Calculate the
number of cc. of N/10 alkali used in the saponification of the esters as ethyl acetate;
1 cc. of N/10 alkali is equivalent to 0.0088 gram of ethyl acetate. Run a blank using
water in place of the distillate and make any necessary correction.

ALDEHYDES.— TENTATIVE.

9 KE AGENTS.

(a) Aldehyde-free alcohol. — Redistil 95% alcohol over sodium or potassium hy-
droxid, then add 2-3 grams per liter of meta-phenylendiamin hydrochlorid, digest
at ordinary temperature for several days (or reflux on a steam bath for several
hours) and then distil slowly, rejecting the first 100 cc. and the last 200 cc. of the
distillate.

(b) Sulphite-fuchsin solution. — Dissolve 0.50 gram of pure fuchsin in 500 cc. of
water, then add 5 grams of sulphur dioxid dissolved in water, make up to 1 liter
and allow to stand until colorless. This solution does not keep indefinitely; there-
fore, prepare in small quantities and keep at a low temperature.

(C) Standard acetaldehyde solution. — Prepare according to the directions of Vasey1
as follows: Grind aldehyde ammonia in a mortar with anhydrous ether and decant
the ether. Repeat this operation several times, then dry the purified salt in a
current of air and finally in vacuo over sulphuric acid. Dissolve 1.386 grams of this
purified aldehyde ammonia in 50 cc. of 95% alcohol by volume, add 22.7 cc. of
N/1 alcoholic sulphuric acid, then make up to 100 cc. and add 0.8 cc. of alcohol
for the volume of the ammonium sulphate precipitate. Allow the mixture to stand
overnight and filter. This solution contains 1 gram of acetaldehyde in 100 cc. and
will retain its strength.

The standard found most convenient for use is 2 cc. of this strong aldehyde
solution diluted to 100 cc. with 50% alcohol by volume. One cc. of this solution
is equivalent to 0.0002 gram of acetaldehyde. This solution should be made up
fresh every day or so, as it loses strength.

10 DETERMINATION.

Determine the aldehyde in the distillate, prepared as directed under 8. Dilute
5-10 cc. of the distillate to 50 cc. with aldehyde-free alcohol 50% by volume, add
25 cc. of the sulphite-fuchsin solution and allow to stand for 15 minutes at 15°C.
The solutions and reagents should be at 15°C. when they are mixed. Prepare
standards of known strength and blanks in the same way. The comparison
standards found most convenient for use contain 0.0001, 0.0002, 0.0004, 0.0005 and
0.0006 gram of acetaldehyde.

FURFURAL.— TENTATIVE.

11 REAGENTS.

(a) Standard furfural solution. — Dissolve 1 gram of redistilled furfural in 100
cc. of 95% alcohol by volume. Standards are made by diluting 1 cc. of this solu-

XVII] DISTILLED LIQUORS 245

tion to 100 cc. with 50% alcohol by volume. One cc. of this solution contains
0.0001 gram of furfural.

(b) Furfural-free alcohol. — Prepare as directed in 9 (a).

12

DETERMINATION.

Dilute 10-20 cc. of the distillate, as prepared under 8, to 50 cc. with furfural-
free alcohol, 50% by volume. Add 2 cc. of colorless anilin and 0.5 cc. of hydro-
chloric acid (sp. gr. 1.125) and keep for 15 minutes in a water bath at about 15°C.
Prepare standards of known strength and blanks in the same way. The compari-
son standards found most convenient for use contain 0.00005, 0.0001, 0.00015, 0.0002,
0.00025 and 0.0003 gram of furfural.

FUSEL OIL.— TENTATIVE.

13 REAGENTS.

(a) Purified carbon tetrachlorid. — Mix crude carbon tetrachlorid with one tenth
its volume of concentrated sulphuric acid, shake thoroughly at frequent intervals
and allow to stand overnight. Wash free of acid and impurities with tap water.
Remove the water, add an excess of sodium hydroxid solution and distil the carbon
tetrachlorid from it.

(b) Oxidizing solution. — Disssolve 100 grams of potassium dichromate in 900 cc.
of water and add 100 cc. of concentrated sulphuric acid.

14 DETERMINATION.

(1) To 100 cc. of the sample add 20 cc. of N/2 sodium hydroxid and saponify the
mixture by boiling for an hour under a reflux condenser; or, (2) Mix 100 cc. of the
liquor with 20 cc. of N/2 sodium hydroxid, allow to stand overnight at room tem-
perature and distil directly. Connect the flask with a distillation apparatus, distil
90 cc, add 25 cc. of water and continue the distillation until an additional 25 cc. are
collected.

Whenever aldehydes are present in excess of 15 parts per 100,000, add to the dis-
tillate 0.5 gram of meta-phenylendiamin hydrochlorid, reflux for an hour, distil
100 cc, add 25 cc. of water and continue the distillation until an additional 25 cc.
are collected.

Approximately saturate the distillate with finely ground sodium chlorid and add
saturated sodium chlorid solution until the specific gravity is 1.10.

Extract this salt solution 4 times with the purified carbon tetrachlorid, using 40,
30, 20 and 10 cc, respectively, and wash the carbon tetrachlorid 3 times with 50
cc. portions of saturated sodium chlorid solution, and twice with saturated sodium
sulphate solution. Then transfer the carbon tetrachlorid to a flask containing 50
cc. of the oxidizing solution and boil for 8 hours under a reflux condenser.

Add 30 cc of water and distil until only about 20 cc. remain; add 80 cc. of water
and again distil until 15-20 cc. are left. Neutralize the distillate to methyl orange,
and titrate with N/10 sodium hydroxid, using phenolphthalein as an indicator.
If the distillations have been properly conducted, the distillate will not show a
marked acid reaction to methyl orange. Should considerably more than 1 cc. of
N/10 alkali be consumed at this point, the result will be unreliable and the deter-
mination should be repeated. One cc. of N/10 sodium hydroxid is equivalent to
0.0088 gram of amyl alcohol.

Rubber stoppers can be used in the saponification and first distillation, hut
corks covered with tinfoil must be used in the oxidation and second distillation.
Corks and tinfoil must be renewed frequently.

246 METHODS OF ANALYSIS [Chap.

Conduct a blank determination upon 100 cc. of carbon tetrachlorid beginning
the blank at that point of the procedure immediately after the extraction and just
before the washings with sodium chlorid and sodium sulphate solutions.

1 5 SUGARS.— TENTATIVE.
Proceed as directed under XVI, 15, 16 or 17.

METHYL ALCOHOL.

16 Trillat Method2.— Tentative.

To 50 cc. of the sample add 50 cc. of water and 8 grams of lime and fractionate
by the aid of Glinsky bulb tubes. Dilute the first 15 cc. of the distillate to 150 cc,
mix with 15 grams of potassium dichromate and 70 cc. of sulphuric acid (1 to 5),
and allow to stand for an hour with occasional shaking.

Distil, reject the first 25 cc. and collect 100 cc. Mix 50 cc. of the distillate with
1 cc. of redistilled dimethylanilin, transfer to a stout, tightly stoppered flask, and
keep on a bath at 70°-80°C. for 3 hours with occasional shaking. Make distinctly
alkaline with sodium hydroxid solution, and distil off the excess of dimethylanilin,
stopping the distillation when 25 cc. have passed over.

Acidify the residue in the flask with acetic acid, shake and test a few cc. by add-
ing 4 or 5 drops of 1% suspension of lead dioxid. If methyl alcohol is present, a
blue coloration occurs which is increased by boiling.

Ethyl alcohol thus treated yields a blue coloration changing immediately to green,
later to yellow, and becoming colorless when boiled.

1 7 Riche and Bardy Method3. — Tentative.

The following method for the detection of methyl alcohol in commercial spirit
of wine depends on the formation of methylanilin violet :

Place 10 cc. of the sample, previously redistilled over potassium carbonate if
necessary, in a small flask with 15 grams of iodin and 2 grams of red phosphorus.
Keep in ice water for 10-15 minutes until action has ceased. Distil off, on a water
bath, the methyl and ethyl iodids formed into about 30 cc. of water. Wash with
dilute alkali to eliminate free iodin. Separate the heavy, oily liquid which settles
and transfer to a flask containing 5 cc. of anilin. If the action be too violent, place
the flask in cold water; if too slow, stimulate by gently warming the flask. After an
hour boil the product with water and add about 20 cc. of 15% sodium hydroxid
solution; when the bases rise to the top as an oily layer, fill the flask up to the neck
with water and draw them off with a pipette. Oxidize 1 cc. of the oily liquid by
adding 10 grams of a mixture of 100 parts of clean sand, 2 of common salt, and 3
of cupric nitrate; mix thoroughly, transfer to a glass tube, and heat to 90°C.
for 8-10 hours. Exhaust the product with warm alcohol, filter and make up to
100 cc. with alcohol. If the sample of spirits is pure, the liquid has a red tint, but,
in the presence of 1% of methyl alcohol, it has a distinct violet shade; with 2.5%
the shade is very distinct, and still more so with 5%. To detect more minute quan-
tities of methyl alcohol, dilute 5 cc. of the colored liquid to 100 cc. with water, and
dilute 5 cc. of this again to 400 cc. Heat the liquid thus obtained in a porcelain
dish and immerse in it a fragment of white merino (free from sulphur) for 30 min-
utes. If the alcohol is pure, the wool will remain white, but, if methyl alcohol is
present, the fiber will become violet, the depth of tint giving a fairly approximate
indication of the proportion of methyl alcohol present.

XVII]

DISTILLED LIQUORS

247

18

Immersion Refractometer Method. (Leach and Lythgoe*) — Tentative.

Determine by the immersion refractometer at 20°C. the refraction of the distil-
late obtained in the determination of alcohol. If, on reference to the table under
19, the refraction shows the percentage of alcohol agreeing with that obtained
from the specific gravity, it may safely be assumed that no methyl alcohol is present.
If, however, there is an appreciable amount of methyl alcohol, the low refractome-
ter reading will at once indicate the fact. If the absence from the solution of re-
fractive substances other than water and the alcohols is assured, this difference in
refraction is conclusive of the presence of methyl alcohol.

The addition of methyl alcohol to ethyl alcohol decreases the refraction in direct
proportion to the amount present; hence the quantitative calculation is readily
made by interpolation in the table under 19, using the figures for pure ethyl and
methyl alcohol of the same alcoholic strength as the sample.

Example. — The distillate has a specific gravity of 0.97080, corresponding to
18.38% alcohol by weight, and has a refraction of 35.8 at 20°C. by the immersion
refractometer; by interpolation in the refractometer table the readings of ethyl and
methyl alcohol corresponding to 18.38% alcohol are 47.3 and 25.4, respectively, the
difference being 21.9; 47.3 - 35.8 = 11.5; (11.5 -^ 21.9) 100 = 52.5, showing that
52.5% of the total alcohol present is methyl alcohol.

19

Table 18.

Scale r

zadingi

of the Zeiss immersion refractometer at 20°C, corresponding i
per cent by weight of methyl and ethyl alcohols.

o each

PER

CENT

SCALE READINGS

PER
CENT
ALCO-
HOL
BT
WEIGHT

SCALE READINGS

PER
CENT
ALCO-
HOL
BT
WEIGHT

SCALE READINGS

PER
CENT
ALCO-
HOL
BT
WEIGHT

SCALE READINGS

ALCO-
HOL
BT
WEIGHT

Methyl
alco-
hol

Ethyl
alco-
hol

Methyl
alco-
hol

Ethyl
alco-
hol

Methyl
alco-
hol

Ethyl
alco-
hol

Methyl
alco-
hol

Ethyl
alco-
hol

0

14.5

14.5

25

29.7

60.1

50

39.8

90.3

75

29.7

101.0

1

14.8

16.0

26

30.3

61.9

51

39.7

91.1

76

29.0

101.0

2

15.4

17.6

27

30.9

63.7

52

39.6

91.8

77

28.3

100.9

3

16.0

19.1

28

31.6

65.5

53

39.6

92.4

78

27.6

100.9

4

16.6

20.7

29

32.2

67.2

54

39.5

93.0

79

26.8

100.8

5

17.2

22.3

30

32.8

69.0

55

39.4

93.6

80

26.0

100.7

6

17.8

24.1

31

33.5

70.4

56

39.2

94.1

81

25.1

100.6

7

18.4

25.9

32

34.1

71.7

57

39.0

94.7

82

24.3

100.5

8

19.0

27.8

33

34.7

73.1

58

38.6

95.2

83

23.6

100.4

9

19.6

29.6

34

35.2

74.4

59

38.3

95.7

84

22.8

100.3

10

20.2

31.4

35

35.8

75.8

60

37.9

96.2

85

21.8

100.1

11

20.8

33.2

36

36.3

76.9

61

37.5

96.7

86

20.8

99.8

12

21.4

35.0

37

36.8

78.0

62

37.0

97.1

87

19.7

99.5

13

22.0

36.9

38

37.3

79.1

63

36.5

97.5

88

18.6

99.2

14

22.6

38.7

39

37.7

80.2

64

36.0

98.0

89

17.3

98.9

15

23.2

40.5

40

38.1

81.3

65

35.5

98.3

90

16.1

98.6

16

23.9

42.5

41

38.4

82.3

66

35.0

98.7

91

14.9

98.3

17

24.5

44.5

42

38.8

83.3

67

34.5

99.1

92

13.7

97.8

18

25.2

46.5

43

39.2

84.2

68

34.0

99.4

93

12.4

97.2

19

25.8

48.5

44

39.3

85.2

69

33.5

99.7

94

11.0

96.4

20

26.5

50.5

45

39.4

86.2

70

33.0

100.0

95

9.6

95.7

21

27.1

52.4

46

39.5

87.0

71

32.3

100.2

96

8.2

94.9

22

27.8

54.3

47

39.6

87.8

72

31.7

100.4

97

6.7

94.0

23

28.4

56.3

48

39.7

88.7

73

31.1

100.6

98

3.5

93.0

24

29.1

58.2

49

39.8

89.5

74

30.4

100.8

99

100

3.5
2.0

92.0
91.0

248 METHODS OF ANALYSIS

20 COLORING MATTERS.-TENTATIVE.
Proceed as directed under XI.

21 WATER-INSOLUBLE COLOR IN WHISKIES.— TENTATIVE.

Evaporate 50 cc. of the sample just to dryness on a steam bath. Take up with
cold water, using approximately 15 cc, filter and wash until the nitrate amounts
to nearly 25 cc. To this filtrate add 25 cc. of absolute alcohol, or 26.3 cc. of 95%
alcohol by volume, and make up to 50 cc. by the addition of water. Mix thor-
oughly and compare in a colorimeter with the original material. Calculate from
these readings the per cent of color insoluble in water.

COLORS INSOLUBLE IN AMYL ALCOHOL.

22 Modified Marsh Method. — Tentative.

Evaporate 50 cc. of whisky just to dryness on a steam bath. Dissolve the
residue in water and 95% alcohol by volume and make to a volume of 50 cc, using
a total volume of 26.3 cc. of 95% alcohol. Place 25 cc. of this solution in a separatory
funnel and add 20 cc. of freshly shaken Marsh reagent (100 cc. of pure amyl alco-
hol, 3 cc. of sirupy phosphoric acid and 3 cc. of water), shaking lightly so as not to
form an emulsion. Allow the layers to separate and repeat this shaking and stand-
ing twice again. After the layers have separated completely draw off the lower
or aqueous layer, which contains the caramel, into a 25 cc. cylinder and make up
to volume with 50% alcohol" by volume. Compare this solution in a colorimeter
with the untreated 25 cc. Calculate the result of this reading to the per cent of
color insoluble in amyl alcohol.

CARAMEL.

23 Amthor Test Modified by Lasche5. — Tentative.

Add 10 cc. of paraldehyde to 5 cc. of the sample in a test tube and shake. Add
absolute alcohol, a few drops at a time, shaking after each addition until the mixture
becomes clear. Allow to stand. Turbidity after 10 minutes is an indication of
caramel.

BIBLIOGRAPHY.

1 Vasey. Guide to the Analysis of Potable Spirits. 1904, p. 31.

2 Abs. Analyst, 1899, 24: 13; Ibid., 211, 212.

3 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 1:98.

4 J. Am. Chem. Soc, 1905, 27: 964.
6 The Brewer Distiller, May, 1903.

XVIII. BEERS.

1 PREPARATION OF SAMPLE.— TENTATIVE.

Remove carbon dioxid by transferring the contents of the bottle to a large flask
and shaking vigorously or by pouring back and forth between beakers, care being
taken that the temperature of the beer is not below 20°C.

2 COLOR.— TENTATIVE.

Determine the depth of color of the sample in a J inch cell with a Lovibond tin-
tometer, using the beer scale. Express the result in terms of a % inch cell.

3 SPECIFIC GRAVITY.— TENTATIVE.

20CC
Determine the specific gravity at -^— '■ by means of a pycnometer.

4 ALCOHOL.— TENTATIVE.
Determine as directed under XVI, 4.

EXTRACT.

5 Method I. — Official.

Measure 25 cc. of the carbon dioxid-free beer at20°C. into a tared, flat-bottomed
platinum dish, approximately 85 mm. in diameter, and evaporate just to dryness
on a steam bath and heat to constant weight in a vacuum oven at 70°C.

6 Method II. — Tentative.

The immersion refractometer reading of the beer at 20°C. minus the immersion
refractometer reading of the distillate at 20°C. times 0.2571 equals the grams of
extract in 100 cc. of beer.

7 Method III.— Tentative.

Calculate the specific gravity of the dealcoholized beer by the following formula:
S = G+ 1- A in which

S = the specific gravity of the dealcoholized beer;
G = the specific gravity of the beer; and

A = the specific gravity of the distillate obtained in the determination
of alcohol.

From IX, 9, ascertain the per cent by weight of extract in the dealcoholized beer
corresponding to the value of S. Multiply the figure thus obtained by S to ob-
tain the grams of extract per 100 cc. of beer.

8 EXTRACT OF ORIGINAL WORT (APPROXIMATE).— TENTATIVE.

Calculate the grams of extract per 100 cc. in the original wort by the following
formula:

O = 2A+ E in which

O = extract of the original wort;

A = alcohol (grams per 100 cc); and

E = extract of the dealcoholized beer (grams per 100 cc).

249

250 METHODS OF ANALYSIS [Chap.

Q DEGREE OF FERMENTATION.— TENTATIVE.

Calculate the degree of fermentation by the following formula:

100 X 2A .
D = ^r in which

D = degree of fermentation;

A = alcohol (grams per 100 cc); and

O = extract of original wort.

10 TOTAL ACIDS.— TENTATIVE.

Proceed as directed under XVT, 25. Express the result as lactic acid, grams per
100 cc. One cc. of N/10 sodium hydroxid is equivalent to 0.0090 gram of lactic
acid.

1 1 VOLATILE ACIDS.-TENTATIVE.

Proceed as directed under XVI, 27. Express the result as acetic acid, grams
per 100 cc.

12 REDUCING SUGARS.— TENTATIVE.

Dilute 25 cc. of the carbon dioxid-free beer, measured at 20°C, with water to
100 cc. of the same temperature. Determine the reducing sugars in 25 cc. of this
solution, as directed under VIII, 42. Express the result as grams of anhydrous
maltose per 100 cc. of beer.

1 3 DEXTRIN.— TENTATIVE.

To 50 cc. of the carbon dioxid-free beer measured at 20°C, add 15 cc. of hydro-
chloric acid (sp. gr. 1.125), dilute to 200 cc, attach to a reflux condenser and keep
in a boiling water bath for 2 hours. Cool, nearly neutralize with sodium hydroxid
solution, complete to a volume of 250 cc, filter and determine dextrose as directed
under VIII, 52 or 54. From the number of grams of dextrose per 100 cc. of beer,
subtract 1.053 times the amount of maltose as found in 12 and multiply the re-
mainder by 0.9 to obtain the number of grams of dextrin per 100 cc of beer.

1 4 DIRECT POLARIZATION.— TENTATIVE.

Read the polarization of the original sample in degrees Ventzke in a 200 mm.
tube at 20°C. If the beer is turbid, clarify by shaking with alumina cream, filter
and correct the reading for dilution.

1 5 GLYCEROL.— TENTATIVE.

Proceed as directed under XVI, 8.

1 6 ASH.— OFFICIAL.

Evaporate to dryness 25 cc. of the carbon dioxid-free sample, measured at 20°C,
and proceed as directed under VIII, 4.

1 7 PHOSPHORIC ACID.-TENTATIVE.

To 25 cc of the carbon dioxid-free beer, measured at 20°C, add 20 cc of '_" j
calcium acetate solution, evaporate to dryness and ignite at low redness to a white
ash. Add 10-15 cc. of boiling nitric acid (1 to 9) and determine phosphoric acid
(P2O5) as directed under I, 9.

XVIII] BEERS 251

1 8 PROTEIN.— OFFICIAL.

Measure, at 20°C... 25 cc. of the carbon dioxid-free beer into a Kjeldahl digestion
flask, add a small amount of tannin to prevent frothing, evaporate to dryness, de-
termine nitrogen as directed under I, 18, 21 or 23, multiply the result by 6.25 and
calculate the percentage of protein,

1 9 PRESERVATIVES.— TENTATIVE.

Proceed as directed under X.

20 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

21 METALS— TENTATIVE.
Proceed as directed under XII.

XIX. VINEGARS.

(Unless otherwise noted, express results as grams per 100 cc.)

1 PHYSICAL EXAMINATION.— TENTATIVE.
Note the appearance, color, odor and taste.

2 PREPARATION OF SAMPLE.— TENTATIVE.

If the sample is turbid, filter before proceeding with the analysis.

3 SPECIFIC GRAVITY.— TENTATIVE.

20°C
Determine the specific gravity at -p— ' by means of a pycnometer.

4 ALCOHOL.— TENTATIVE.

Measure 100 cc. of the sample into a round-bottomed, distillation flask. Make
faintly alkaline with saturated sodium hydroxid solution, add a small piece of
paraffin, distil almost 50 cc, make up to 50 cc. at the temperature of the sample

20 °C
and determine the specific gravity at -^- '■ by means of a pycnometer. Obtain from

XVT, 5, the per cent by volume, or grams per 100 cc, noting that the alcoholic
strength of the distillate is twice that of the original vinegar.

GLYCEROL.— TENTATIVE.

5 REAGENTS.

(a) Strong potassium dichromate solution. — Dissolve 74.56 grams of dry, recrystal-
lized potassium dichromate in water, add 150 cc. of concentrated sulphuric acid,
cool and make up to 1 liter at 20°C. One cc. of this solution is equivalent to 0.01
gram of glycerol. The high coefficient of expansion of this strong solution necessi-
tates its preparation at exactly 20°C. and the measurement of any definite volume
at the same temperature. If desired, the measurements may be made at room
temperature by means of a weighing burette, the volume used in this case being

ascertained by dividing the weight of the solution used by its specific gravity at

20 -C.

4°

(b) Dilute potassium dichromate solution. — Measure 25 cc. of the strong potas-
sium dichromate solution at exactly 20°C. into a 500 cc. volumetric flask, dilute with
water and make up to the mark at room temperature. Twenty cc. of this solution
are equivalent to 1 cc. of (a).

(C) Ferrous ammonium sulphate solution. — Dissolve 30 grams of crystallized fer-
rous ammonium sulphate in water, add 50 cc. of concentrated sulphuric acid, cool
and dilute at room temperature. One cc. of this solution is approximately equiva-
lent to 1 cc. of (b). Its value changes slightly from day to day and it must be
standardized against (b) whenever used.

(d) Potassium fcrricyanid indicator. — Dissolve 1 gram of crystallized potassium
ferricyanid in 50 cc. of water. This solution must be freshly prepared.

(e) Milk of lime. — Introduce 150 grams of calcium oxid, selected from clean, hard
lumps, prepared preferably from marble, into a large porcelain or iron dish, slake
with water, cool and add sufficient water to make 1 liter.

253

254 METHODS OF ANALYSIS [Chap.

(f ) Silver carbonate. — Dissolve 0.1 gram of silver sulphate in about 50 cc. of water,
add an excess of sodium carbonate solution, allow the precipitate to settle and
wash with water several times by decantation until the washings are practically
neutral. This reagent must be freshly prepared immediately before use.

6 DETERMINATION.

All evaporations should be made on a water bath, the temperature of which is main-
tained at 85°-90°C.

Evaporate 100 cc. of the vinegar to 5 cc, add 20 cc. of water and again evaporate
to 5 cc. to expel acetic acid. Treat the residue with about 5 grams of fine sand and
15 cc. of the milk of lime and evaporate almost to dryness, with frequent stirring,
avoiding the formation of a dry crust or evaporation to complete dryness. Treat
the moist residue with 5 cc. of water, rub into a homogeneous paste, then add
slowly 45 cc. of absolute alcohol, washing down the sides of the dish to remove
adhering paste, and stir thoroughly. Heat the mixture on a water bath, with
constant stirring, to incipient boiling, transfer to a suitable vessel and centrifu-
galize. Decant the clear liquid into a porcelain dish and wash the residue with
several small portions of hot 90% alcohol by volume by aid of the centrifuge.
(If a centrifuge is not available, decant the liquid through a fluted filter into a
porcelain dish. Wash the residue repeatedly with small portions of hot 90% alco-
hol, twice by decantation, and then by transferring all the material to the filter.
Continue the washing until the filtrate amounts to 150 cc.) Evaporate to a sirupy
consistency, add 10 cc. of absolute alcohol to dissolve this residue and transfer to
a 50 cc. glass-stoppered cylinder, washing the dish with successive small portions of
absolute alcohol until the volume of the solution amounts to 20 cc. Then add
3 portions of 10 cc. each of anhydrous ether, shaking thoroughly after each addi-
tion. Let stand until clear, then pour off through a filter, and wash the cylinder
and filter with a mixture of* 2 volumes of absolute alcohol and 3 of anhydrous ether.
If a heavy precipitate has formed in the cylinder, centrifugalize at low speed, de-
cant the clear liquid and wash 3 times with 20 cc. portions of the alcohol-ether
mixture, shaking the mixture thoroughly each time and separating the precipitate
by means of the centrifuge. Wash the paper with the alcohol-ether mixture, and
evaporate the filtrate and washings on the water bath to about 5 cc, add 20 cc.
of water and again evaporate to 5 cc. ; again add 20 cc. of water and evaporate to 5
cc ; finally add 10 cc. of water and evaporate to 5 cc.

These evaporations are necessary to remove all the ether and alcohol, and, when
conducted at 85°-90°C., result in no loss of glycerol if the concentration of the latter
is less than 50%.

Transfer the residue with hot water to a 50 cc graduated flask, cool, add the
silver carbonate, prepared from 0.1 gram of silver sulphate, shake and allow to stand
10 minutes; then add 0.5 cc. of basic lead acetate solution [VIII, 13 (a)], shake
occasionally and allow to stand 10 minutes; make up to the mark, shake well, filter,
rejecting the first portion of the filtrate, and pipette 25 cc of the clear filtrate into
a 250 cc. volumetric flask.

Add 1 cc. of concentrated sulphuric acid to precipitate the excess of lead and
then 30 cc. of the strong potassium dichromate solution. Add carefully 21 cc. of
concentrated sulphuric acid, rotating the flask gently to mix the contents and avoid
violent ebullition, and then place in a boiling water bath for exactly 20 minutes.
Remove the flask from the bath, dilute, cool and make up to the mark at room tem-
perature. The amount of strong dichromate solution used must be sufficient to

XEX] VINEGARS 255

leave an excess of about 12.5 cc. at the end of the oxidation, the amount given above
(30 cc.) being sufficient for ordinary vinegar containing about 0.35 gram or less of
glycerol per 100 cc.

Standardize the ferrous ammonium sulphate solution against the dilute potas-
sium dichromate solution by introducing from the respective burettes approxi-
mately 20 cc. of each of the 2 solutions into a beaker containing 100 cc. of water.
Complete the titration using the potassium ferricyanid solution as an outside indi-
cator. From this titration calculate the volume (F) of the ferrous ammonium sul-
phate solution equivalent to 20 cc. of the dilute and also, therefore, to 1 cc. of the
strong dichromate solution.

In place of the dilute dichromate solution, substitute a burette containing the
oxidized glycerol with an excess of the strong dichromate solution and ascertain how
many cc. are equivalent to (F) cc. of the ferrous ammonium sulphate solution and
also, therefore, to 1 cc. of the strong dichromate solution. Then 250 divided by this
last equivalent equals the number of cc. of the strong dichromate solution pres-
ent in excess in the 250 cc. flask after oxidation of the glycerol.

The number of cc. of the strong dichromate solution added, minus the excess
found after oxidation, multiplied by 0.02 gives the grams of glycerol per 100 cc. of
vinegar.

7 SOLIDS.— TENTATIVE.

Measure 10 cc. of the sample into a tared, flat-bottomed platinum dish of 50
mm. bottom diameter, evaporate on a boiling water bath for 30 minutes, and dry
for exactly 2\ hours in a water oven at the temperature of boiling water. Cool in
a desiccator and weigh. It is essential that the size and shape of the dish and the
time of drying be followed strictly.

8 TOTAL REDUCING SUBSTANCES BEFORE INVERSION.— TENTATIVE.

Proceed as directed under VIII, 25, using 10 cc. of the sample. In the case of
malt vinegar, express the results as dextrose; in all other cases as invert sugar.

9 REDUCING SUGARS BEFORE INVERSION AFTER EVAPORATION.— TENTATIVE.

Evaporate 50 cc. of the sample on the water bath to a volume of 5 cc. Add 25
cc. of water and again evaporate to 5 cc. Transfer to a 100 cc. volumetric flask,
make up to the mark, and proceed as directed under 8, using a quantity equivalent
to 10 or 20 cc. of the sample.

I 0 REDUCING SUGARS AFTER INVERSION.— TENTATIVE.

Proceed as directed under 9. After the last evaporation to 5 cc. transfer to a
100 cc. volumetric flask with 70 cc. of water, and invert as directed under VIII,
14. Nearly neutralize with sodium hydroxid solution, make up to the mark and
proceed as directed under VIII, 25, using a quantity equivalent to 10 or 20 cc. of
the sample.

II LEAD PRECIPITATE.-TENTATIVE.

To 10 cc. of the sample in a test tube, add 2 cc. of 20% lead acetate solution,
shake and Let stand 30 minutes. Describe the precipitate as turbid, light, normal,
heavy or very heavy.

12' POLARIZATION.-TENTATIVE.

If the lead precipitate is normal, add to 50 cc. of th" sample 5 cc. of basic lead
acetate solution [VIII, 13 (tl)], shake, let stand 30 minutes, filter and poll

256 METHODS OF ANALYSIS [Chap.

preferably in a 200 mm. tube, correcting for dilution. If basic lead acetate gives
only a turbidity, add to the sample, already treated with basic lead acetate, 10 cc.
of alumina cream [VIII, 13 (b)], shake, let stand 30 minutes, filter and polarize,
correcting for dilution. In the case of malt vinegar, treat 100 cc. of the sample with
5 cc. of 10% phosphotungstic acid solution and filter. To 50 cc. of the filtrate add
5 cc. of the basic lead acetate solution, filter and polarize, correcting the reading
obtained for dilution.

1 3 ASH.— TENTATIVE.

(a) Measure 25 cc. of the vinegar into a tared platinum dish, evaporate to dry-
ness on the steam bath and proceed as directed under VIII, 4.

(b) Evaporate 25 cc. of the sample to dryness as directed under (a), heat in a
muffle at low heat to expel inflammable gases, treat the charred portion with a few
cc. of water, and evaporate to dryness on a water bath; replace in the muffle at low
redness for 15 minutes, and continue the alternate evaporation and heating until
a white or gray ash is obtained, at no time exceeding a dull red heat; cool in a
desiccator and weigh.

Useful information may often be obtained by noting the odor given off by the
solids during charring.

1 4 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE.

Treat the ash, obtained in 13, as directed under IX, 17.

1 5 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE.

Proceed as directed under IX, 18, expressing the result as the number of cc.
of N/10 hydrochloric acid required to neutralize the soluble ash from 100 cc. of the
vinegar.

1 g SOLUBLE AND INSOLUBLE PHOSPHORIC ACID.-TENTATIVE.

Determine phosphoric acid in the water-soluble and water-insoluble portions of
the ash as directed under I, 9, dissolving the water-insoluble portion in about
50 cc. of boiling nitric acid (1 to 9). Express the result as mg. of phosphorus
pentoxid (P2O1,) in 100 cc. of the vinegar.

1 7 TOTAL ACIDS.— TENTATIVE.

Dilute 10 cc. of the sample with recently boiled and cooled water until it appears
very slightly colored, and titrate with N/2 alkali, using phenolphthalein as an
indicator. One cc. of N/2 alkali is equivalent to 0.030 gram of acetic acid.

1 8 FLXED ACIDS.-TENTATIVE.

Measure 10 cc. of the vinegar into a 200 cc. porcelain casserole, evaporate just to
dryness, add 5-10 cc. of water, and again evaporate; repeat until at least 5 evapora-
tions have taken place. Add about 200 cc. of recently boiled and cooled wafer and
titrate with N/10 alkali, using phenolphthalein as an indicator. One cc. of N/10
alkali is equivalent to 0.0067 gram of malic acid.

1 9 VOLATILE ACIDS.-TENTATIVE.

To obtain the volatile acids subtract the fixed acids, calculated as acetic acid,
from the total acids.

XIX] VINEGARS 257

20 COLOR.— TENTATIVE.

Determine the depth of color in a Lovibond tintometer by good, reflected day-
light, using a £ inch cell and the brewer's scale. Express the result in terms of
a | inch cell.

FORMIC ACID.

21 Fincke Method1. — Tentative.

Employ the apparatus described under X, 39, Fig. 6. Introduce 100 cc. of the
sample into flask (A), add 0.4-0.5 gram of tartaric acid, and place in position as
shown in Fig. 6, the flask (B) having previously been charged with a suspension of
15 grams of calcium carbonate in 100 cc. of water. Heat the contents of flasks (A)
and (B) to boiling and distil with steam from the generator (S), the vapor passing
first through the sample in flask (A), then through the boiling suspension of cal-
cium carbonate in flask (B), after which it is condensed and measured in the re-
ceiver (C). Maintain the volume of liquid in flask (B) as nearly constant as pos-
sible and reduce the volume of the sample in flask (A) to 30-40 cc. by heating with
small Bunsen flames, the distillation being continued until 1 liter of distillate is
collected. Disconnect the apparatus, filter the calcium carbonate suspension, and
wash the calcium carbonate that remains on the paper with a little hot water.
Render the filtrate faintly acid with hydrochloric acid, add 10-15 cc. of mercuric
chlorid reagent [ X, 38 (b) ], mix and heat on a boiling water bath for 2 hours. Filter
on a tared Gooch, wash the precipitate thoroughly with cold water and finally with
a little alcohol. Dry in a boiling water oven for 30 minutes, cool in a desiccator,
weigh, and calculate the weight of formic acid present by multiplying the weight
of the precipitate by 0.0975.

22 ALCOHOL PRECIPITATE.— TENTATIVE.

Evaporate 100 cc. of the vinegar to about 15 cc. When there is considerable
sugar in the vinegar, if the sample is evaporated to too low a volume, a gummy or
stringy precipitate is formed on adding the^lcohol instead of a flocculent one. When
the sugar content is high, therefore, the evaporation should not be carried beyond
20 cc. To this residue add slowly and with constant stirring 200 cc. of 95% alcohol
by volume and allow the mixture to stand overnight. From this point proceed
as directed under XIII, 18, beginning with the sentence, "Filter and wash with
80% alcohol by volume".

23 PENTOSANS.-TENTATIVE.

Proceed as directed in VIII, 64, except that 100 cc. of the vinegar and 43 cc. of
hydrochloric acid (sp. gr. 1.19) are used in beginning the distillation.

TARTARIC ACID AND TARTRATES.

24 Qualitative Test. — Tentative.

Evaporate 50 cc. of the vinegar in a porcelain dish to a volume of about 10 cc,
filter into a test tube, add 1 cc. of 25% calcium chlorid solution and 2 cc. of 50%
ammonium acetate solution and allow to stand overnight. In the presence of tar-
taric acid a deposit of calcium tartrate is formed, the crystals of which may be
identified under the microscope by their characteristic form.

25 TOTAL TARTARIC ACID.-TENTATIVE.

Evaporate 200 cc. of the sample to a sirupy consistency to remove excess of acetic
acid, dilute to the original volume with water in a volumetric flask, determine the

258 METHODS OF ANALYSIS

acidity as directed in 17, and determine total tartaric acid in a 100 cc. aliquot as
directed under XVI, 29, except that 20 cc. of alcohol are used in the precipitation
instead of 15 cc.

FREE MINERAL ACIDS.

26 Logwood Method2. — Tentative.

Prepare an extract of logwood as follows: Pour 100 cc. of boiling water upon 2
grams of fresh logwood chips, allow the infusion to stand for a few hours and filter.
Place drops of the liquid on a porcelain surface and dry on a water bath. Add to
one of the spots a drop of the vinegar to be tested (after concentration if desirable)
and evaporate to dryness. A yellow tint remains if free mineral acids are absent,
a red tint if they are present.

27 Methyl Violet Method.— Tentative.

Add 5-10 cc. of water to 5 cc. of vinegar and, after mixing well, add 4 or 5 drops
of methyl violet solution (1 part of methyl violet 2B in 10,000 parts of water). A
blue or green coloration indicates the presence of a free mineral acid.

28 Quantitative Method. {Hehner Method) — Tentative.

To a measured amount of the sample add a measured excess of standard alkali,
evaporate to dryness, incinerate and titrate the ash with standard acid, using
methyl orange as an indicator. The difference between the number of cc. of alkali
first added and the number of cc. of acid needed to titrate the ash represents the free
mineral acid present.

29 METALS.— TENTATIVE.
Proceed as directed under XII.

DEXTRIN.

30 Qualitative Test. — Tentative.

Evaporate 100 cc. of the vinegar to a volume of about 15 cc. Add slowly and
with constant stirring 200 cc. of 95% alcohol by volume and allow to stand over-
night. The precipitate formed should be tested for dextrin by the optical rotation
and color reaction with iodin.

SPICES AND ADDED PUNGENT MATERIALS.

31 Qualitative Test. — Tentative.

Neutralize exactly a portion of the vinegar and test by taste and smell. Agitate
the liquid with ether in a separatory funnel, remove and evaporate the ethereal
layer, and note the odor and taste of the residue.

32 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

33 PRESERVATIVES.— TENTATIVE.
Proceed as directed under X.

BIBLIOGRAPHY.

1 Z. Nahr. Genussm., 1911, 21: 1; 22:88.

2 Alien. Commercial Organic Analysis. 4th ed., 1909-14, 1: 503.

XX. FLAVORING EXTRACTS.

VANILLA EXTRACT AND ITS SUBSTITUTES.

1 SPECIFIC GRAVITY.— TENTATIVE.

20°C
Determine the specific gravity at -js—' by means of a pycnometer

2 ALCOHOL.-OFFICIAL.
Proceed as directed under XVII, 2 or 3.

3 GLYCEROL.-TENTAT1VE.

Proceed as directed under XVT, 7, 8 or 9, the method selected depending upon
the amount of sugar present, employing an amount of the sample containing 0.10-
0.40 gram of glycerol.

VANILLIN AND COUMARIN.
Modified Hess and Prescott Method1. — Tentative.

(This method is not applicable to concentrated vanillin and coumarin

preparations in which the amount of vanillin and coumarin present

exceeds the quantity dissolved by 100 cc. of water at 20°C.

In such cases employ a smaller amount of the sample

and dilute to 50 cc.)

4 PREPARATION OF SOLUTION.

Measure 50 cc. of the extract at 20°C. into a 250 cc. beaker with marks showing
volumes of 80 and 50 cc, dilute to 80 cc. and evaporate to 50 cc. on a water bath kept
at 70°C. Dilute again with water to 80 cc. and evaporate to 50 cc. Transfer to a
100 cc. flask, rinsing the beaker with hot water; add 25 cc. of 8% lead acetate solu-
tion; make up to the mark with water, shake and allow to stand 18 hours (over-
night) at 37°-40°C. Decant into a small, dry filter, reserving the filtrate for the
determination of vanillin and coumarin, the normal lead number, 6, and the
residual color, 14.

5 DETERMINATION.

Transfer a 50 cc. aliquot of the filtrate to a separatory funnel and extract with 4
successive 15 cc. portions of ether (previously washed twice with an equal volume
of water to remove alcohol). Wash the combined ether solutions 4 or 5 times with
2% ammonium hydroxid solution (2% NH3 by weight), using 10 cc. the first lime
and 5 cc. thereafter, and reserve the ether solution for the determination of cou-
marin. Slightly acidify the combined ammoniacal solutions with hydrochloric
acid; cool and extract in a separatory funnel with 4 portions of washed ether, using
about 40 cc. altogether. Evaporate the ethereal solutions at room tempera tun-,
dry over sulphuric acid and weigh. If the residue is considerably discolored or
gummy, re-extract in the dry state with boiling petroleum ether (b. p. 40°C. or
below) not less than 15 times; evaporate the solvent, dry and weigh. The residue
should now be white, crystalline vanillin, with a melting point of approximately

259

260 METHODS OF ANALYSIS [Chap.

80°C. A small amount of this residue, dissolved in 2 drops of concentrated hydro-
chloric acid, should develop a pink color upon the addition of a crystal of resorcin.
Evaporate at room temperature the original ether extract of the sample, from
which the vanillin has been removed by means of ammonium hydroxid, and dry
over sulphuric acid. The residue, if pure coumarin, should melt at approximately
67°C. and should respond to Leach's test for coumarin as follows: A small por-
tion of the residue, dissolved in not more than 0.5 cc. of hot water, should yield
a brown precipitate upon the addition of a few drops of N/10 iodin. This pre-
cipitate finally gathers in green flecks, leaving a clear, brown solution. The
reaction is especially marked if the reagent is applied with a glass rod to a few
drops of the solution on a white plate or tile.

6 NORMAL LEAD NUMBER2.— TENTATIVE.

To a 10 cc. aliquot of the filtrate from the lead acetate precipitate, as obtained
in 4, add 25 cc. of water, 0.5-1.0 cc. of sulphuric acid, and 100 cc. of 95% alcohol by
volume. Let stand overnight, filter on a Gooch crucible, wash with 95% alcohol,
dry at a moderate heat, ignite at low redness for 3 minutes, taking care to avoid
the reducing flame, and weigh. Conduct a blank determination employing water
containing 4 or 5 drops of glacial acetic acid in place of the sample. The normal lead
number is calculated by the following formula:

., 100 X 0.6831 (S-W) 10RrorQ UM . . . .

P = = 13.662 (S — H ) in which

5

P = normal lead number (grams of metallic lead in the precipitate obtained
from 100 cc. of the sample);

S = grams of lead sulphate corresponding to 2.5 cc. of the lead acetate solu-
tion as determined in a blank analysis; and

W = grams of lead sulphate obtained in 10 cc. of the filtrate from the lead
acetate precipitate, as obtained in 4.

7 TOTAL SOLIDS.-TENTATIVE.

Proceed as directed under IX, 4, employing 10 grams of the sample.

8 ASH.-OFFICIAL.

Evaporate 10 grams of the extract and determine the ash as directed under

VIII, 4.

9 ASH CONSTITUENTS.— TENTATIVE.

Proceed as directed under III or XXVIII, 21-26, inclusive.

10 SUCROSE.— TENTATIVE.
Determine as directed under VIII, 14 or 18.

VANILLA R33INS.

11 Qualitative Test. — Tentative.

Place 50 cc. of the extract in a glass dish and evaporate the alcohol on a water
bath. When the alcohol is removed, make up to about the original volume with
hot water. If alkali has not been used in the manufacture of the extract, the resins
will appear as a flocculent red to brown residue. Acidify with acetic acid to free
the resins from the bases, separating the resins completely and leaving a partly
decolorized, clear, supernatant liquid after standing a short time. Collect the
resins on a filter, wash with water and reserve the filtrate for further tests.

XXj FLAVORING EXTRACTS 261

Place a portion of the filter with the attached resins in a few cc. of dilute potas-
sium hydroxid solution. The resins are dissolved, giving a deep red solution;
acidify, and the resins are precipitated.

Dissolve a portion of the resins in alcohol. To one portion add a few drops of
ferric chlorid solution; to another portion hydrochloric acid; neither produces any
marked change in color. Most resins, however, in alcoholic solution give color
reactions with ferric chlorid or hydrochloric acid.

To a portion of the filtrate obtained above add a few drops of basic lead acetate
solution. The precipitate is so bulky as to almost solidify, due to the excessive
amount of organic acids, gums and other extractive matter. The filtrate from
this precipitate is almost colorless.

Test another portion of the filtrate from the resin for tannin with a solution of
gelatin. Tannin is present in varying but small quantities, but should not be
present in great excess.

12 METHYL ALCOHOL.— TENTATIVE.

Proceed as directed under XVII, 16, 17 or 18, using the distillate from the de-
termination of alcohol, 2.

13 COLOR VALUE.-TENTATIVE.

Pipette 2 cc. of the extract into a 50 cc. graduated flask and make up to the mark
with a mixture of equal parts of 95% alcohol by volume and water. Determine
the color value of this diluted extract in terms of red and yellow by means of a
Lovibond tintometer, using a 1 inch cell. To obtain the color value of the original
extract, multiply the figures for each color by 25.

14 RESIDUAL COLOR AFTER PRECIPITATION WITH LEAD ACETATE3.— TENTATIVE.

Determine the color value, in terms of red and yellow, of the filtrate from the
lead acetate precipitate as obtained in 4, using a 1 inch Lovibond cell. Multiply
the reading by 2 to reduce the results to the basis of the original extract. If the
actual reading of the solution is greater than 5 red and 15 yellow, as may happen
if the extract is highly colored with caramel, a \ or \ inch cell should be employed,
and the readings multiplied, respectively, by 4 or 8. Divide the figures for red and
yellow, respectively, by the corresponding figures of the original extract and mul-
tiply the quotients by 100, to obtain the percentages of the 2 colors remaining in
the lead acetate filtrate.

Calculate also the ratio of red to yellow in both extract and lead acetate filtrate.

COLORS INSOLUBLE IN AMYL ALCOHOL.

15 Modified Marsh Method. — Tenia! ire.

Proceed as directed under XVII, 22, using 25 cc. of the extract and shaking with
25 cc of the Marsh reagent instead of 20 cc.

16 COLORING MATTERS OTHER THAN CARAMEL. -TENTATIVE.
Proceed as directed under XI.

LEMON AND ORANGE EXTRACTS.

17 SPECIFIC GRAVITY.-TENTATIVE.

20 "C
Determine the specific gravity at -p ---' by means of :i pycnometer.

262 METHODS OF ANALYSIS [Chap.

1 8 ALCOHOL.— TENTATIVE.

Dilute 50 cc. of the extract, measured at 20°C, with water to about 200 cc, allow
the mixture to stand until the oil separates in a clear layer at the top, or centrifugal-
ize, then make up to the mark, using the lower meniscus of the oil. Pour the mixture
into a dry Erlenmeyer flask containing 5 grams of light magnesium carbonate,
stopper, shake well and filter quickly through a large, dry, folded filter. Intro-
duce a 150 cc. aliquot of the filtrate, measured at 20°C, into a 300-500 cc. distilla-
tion flask, attach the flask to a vertical condenser and distil almost 100 cc. Com-
plete the volume of the distillate to 100 cc. at 20°C, mix well and determine the

20°C
specific gravity at -p— '- • Ascertain the corresponding per cent of alcohol by volume

from XVI, 5 and multiply the result thus obtained by 2| to obtain the percentaee
of alcohol by volume in the original sample.

1 9 GLYCEROL— TENTATIVE.
Proceed as directed under 3.

LEMON AND ORANGE OILS.

20 By Polarization. (Mitchell Method) — Tentative.

Without diluting polarize the extract at 20°C. in a 200 mm. tube. Divide the
reading in degrees Ventzke by 3.2 in the case of lemon extract and by 5.2 in the
case of orange extract; in the absence of other optically active substances, the re-
sult will be the percentage of oil by volume. A small amount of cane sugar is occa-
sionally present; if so, determine as directed under 28 and correct the reading
accordingly.

21 By Precipitation. (Mitchell Method) — Tentative.

Pipette 20 cc. of the extract into a Babcock milk bottle, add 1 cc. of hydrochloric
acid (1 to 1), then 25-28 cc. of water previously warmed to 60°C, mix, let stand
in water at 60°C. for 5 minutes, centrifugalize for 5 minutes, fill with warm water
to bring the oil into the graduated neck of the flask, again centrifugalize for 2 min-
utes, place the flask in water at 60°C. for a few minutes and note the per cent of oil
by volume. If oil of lemon is present in amounts over 2%, add 0.4% to the per-
centage of oil noted to correct for the solubility of the oil. If less than 2% and
more than 1% is present, add 0.3% for this correction.

When the extract is made in accordance with the U. S. P., the results by the
methods given under 20 and 21 should agree within 0.2%.

To obtain the per cent by weight from the per cent by volume, as found by either
of these methods, multiply the volume percentage by 0.86 in the case of lemon ex-
tracts, and by 0.S5 in the case of orange extracts, and divide the result by the specific
gravity of the original extract.

TOTAL ALDEHYDES.

Chace Method*. — Tentative.

22 REAGENTS.

(a) Aldehyde-free alcohol. — Allow 95% alcohol by volume, containing 5 grams
of meta-phenylendiamin hydrochlorid per liter, to stand for 24 hours with fre-
quent shaking. (Nothing is gained by previous treatment with potassium hy-
droxid.) Boil under a reflux condenser for at least 8 hours, longer if necessary
allow to stand overnight and distil, rejecting the first 10 and the last 5 per cent

XX] FLAVORING EXTRACTS 263

which come over. Store in a dark, cool place in well filled bottles. Twenty-five cc.
of this alcohol, on standing 20 minutes at 14°-16°C. with 20 cc. of the sulphite fuchsin
solution, should develop only a faint pink coloration. If a stronger color is de-
veloped, repeat the treatment with meta-phenylndiamin hydrochlorid as above.

(b) Sulphite- fuchsin solution. — Dissolve 0.5 gram of fuchsin in 250 cc. of water,
add an aqueous solution of sulphur dioxid containing 16 grams of the gas, allow to
stand until colorless, or nearly so, and make up to 1 liter with water. Let stand 12
hours before using and keep in a refrigerator. This solution is liable to deteriorate
and should be reasonably fresh when used.

(C) Standard citral solution. — Use 0.5 or 1 mg. of C.P. citral per cc. in 50% alde-
hyde-free alcohol.

23

DETERMINATION.

Weigh approximately 25 grams of the extract in a stoppered weighing flask,
transfer to a 50 cc. flask and make up to the mark at room temperature with alde-
hyde-free alcohol. Measure, at room temperature, 2 cc. of this solution into a
comparison tube. Add 25 cc. of the aldehyde-free alcohol (previously cooled to
14°-16°C), then 20 cc. of the sulphite-fuchsin solution (also cooled) and finally make
up to the 50 cc. mark with more aldehyde-free alcohol. Mix thoroughly, stopper
and keep at 14°-16°C. for 15 minutes. Prepare a standard for comparison at the
same time and in the same manner, using 2 cc. of the standard citral solution, and
compare the colors developed. Calculate the amount of citral present and re-
peat the determination, using a quantity sufficient to give the sample approxi-
mately the strength of the standard. From this result calculate the amount of
citral in the sample. If the comparisons are made in Nessler tubes, standards
containing 1, 1.5, 2, 2.5, 3, 3.5, and 4 mg. of citral, may be prepared and the trial
comparison made against these, the final comparison being made with standards
lying between 1.5 and 2.5 mg. with 0.25 mg. increments.

It is absolutely essential to keep the reagents and comparison tubes at the re-
quired temperature, 14°-16°C. Where the comparisons are made in a bath (this being
possible only where the bath is of glass), the standards should be discarded within
25 minutes after adding the sulphite-fuchsin solution. Give samples and standards
identical treatment.

CITRAL.

Hiltner Method5. — Tentative.

24 REAGENTS.

(a) Meta-phenylendiamin hydrochlorid solution. — Prepare a 1% solution of meta-
phenylendiamin hydrochlorid in 95% alcohol by volume. Decolorize, if neces-
sary, by shaking with fuller's earth and filter through a double filter. The solution
should be bright and clear, free from suspended matter, and practically colorless.
Prepare this solution only for immediate use.

(b) Alcohol. — For the analysis of lemon extracts, 90-95% alcohol by volume
should be used, but for terpeneless extracts, 40-50% alcohol by volume is sufficient.
Filter to remove any suspended matter. The alcohol need not be purified from
aldehyde. If not practically colorless, render slightly alkaline with sodium hvdroxid
and distil.

25 DETERMINATION.

All of the operations may be carried on at room temperature Weigh 25 grains
of the extract into a 50 cc. graduated flask and make up to the mark with alcohol.

264 METHODS OF ANALYSIS [Chap.

Stopper the flask and mix the contents thoroughly. Pipette 2 cc. of this solution
into a colorimeter tube; add 10 cc. of the meta-phenylendiamin hydrochlorid solu-
tion and complete the volume to 50 cc. (or other standard volume) with alcohol.
Compare at once the color with that of the standard, prepared at the same time,
using 2 cc. of standard citral solution and 10 cc. of the meta-phenylendiamin hy-
drochlorid solution, and making up to standard volume with alcohol. From the
result of this first determination, calculate the amount of standard citral solution
that should be used in order to give approximately the same citral strength as the
sample under examination; then repeat the determination.

26 TOTAL SOLIDS.-OFFICIAL.

Proceed as directed under XVII, 5, employing 10 cc. of the sample measured
at 20°C.

27 ASH.-OFFICLAL.

Ignite the residue from 10 cc. of the extract as directed under VIII, 4.

28 SUCROSE.— TENTATIVE.

Neutralize the normal weight of the extract, evaporate to dryness, wash several
times with ether, dissolve in water and determine as directed under VIII, 14 or 18.

29 METHYL ALCOHOL.-TENTATIVE.

Proceed as directed under XVII, 16, 17 or 18, using the distillate from the
determination of alcohol, 18.

Coloring Matters.

30 general.— tentative.
Proceed as directed under XI.

31 LEMON AND ORANGE PEEL COLOR.

Albrech Method. — Tentative.
Place a few cc. of the extract in each of 2 test tubes; to one, add slowly 3-4 vol-
umes of concentrated hydrochloric acid; to the other, several drops of concentrated
ammonium hydroxid. If the color is due to lemon or orange peel only it is materi-
ally deepened by such treatment.

LEMON AND ORANGE OILS.

32 SPECIFIC GRAVITY.— TENTATIVE.

20°C
Determine the specific gravity at 4„ ' by means of a pycnoineter.

33 INDEX OF REFRACTION.-TENTATIVE.

Determine the index of refraction with any standard instrument, making the
reading at 20°C.

34 OPTICAL ROTATION.— TENTATIVE.

Determine the rotation at 20°C. with any standard instrument, using a 50 mm.
tube and sodium light. The results should be stated in angular degrees on a 100
mm. basis. If instruments having the sugar scale are used, the reading on orange
oils is above the range of the scale, but readings may be obtained by the use of

XX] FLAVORING EXTRACTS 265

standard laevo-rotatory quartz plates, or by the use of a 25 mm. tube. The true
rotation cannot be obtained by diluting the oil with alcohol and correcting the
rotation in proportion to the dilution.

CITRAL.

Kleber Method3. — Tentative.

35 REAGENTS.

(a) Phenylhydrazin solution. — Prepare a 10% solution in absolute alcohol. A
sufficiently pure product can be obtained by distilling the commercial article,
rejecting the first portions coming over which contain ammonia.

(b) N/2 hydrochloric acid.

36 DETERMINATION.

Weigh 15 grams of the sample into a small, glass-stoppered flask; add 10 cc. of the
phenylhydrazin solution. Allow to stand 30 minutes at room temperature, titrate
with N/2 hydrochloric acid, using either methyl or ethyl orange as an indicator.
Titrate similarly 10 cc. of the phenylhydrazin solution. The difference in the num-
ber of cc. of N/2 acid used in these 2 titrations, multiplied by the factor 0.076, gives
the weight of citral in the sample. If difficulty is experienced in detecting the end
point of the reaction, titrate until the solution is distinctly acid, transfer to a sepa-
ratory funnel, and draw off the alcoholic portion. Wash the oil with water, adding
the washings to the alcoholic solution, titrate back with N/2 alkali and make the
necessary corrections.

37 Hiltner Method3. — Tentative.

Weigh 2 grams of lemon oil or 8 grams of orange oil into a 100 cc. graduated flask,
dilute to the mark with 95% alcohol by volume and proceed as under 25, using
2 cc. of the dilute solution for the comparison.

TOTAL ALDEHYDES.

38 Chace Method. — Tentative.

Weigh a small quantity of the sample into a small, stoppered flask and dilute
with aldehyde-free alcohol in the proportion of 2 grams of lemon oil or 4 grams of
orange oil to 100 cc. of solution. Determine the total aldehydes as directed under
23, expressing the result as citral.

39 PHYSICAL CONSTANTS OF THE 10 PER CENT DISTELLATE7.-TENTATIVE.

Place 50 cc. of the sample in a 3-bulb Ladenburg flask having the main bulb 6
cm. in diameter and of 120 cc. capacity and the condensing bulbs of the following
dimensions: 3.5 cm., 3 cm., 2.5 cm.; the distance from the bottom of the flask to
the opening of the side arm should be 20 cm. Distil the oil at the rate of 2 cc. per
minute until 5 cc. have been distilled. Determine the refractive index and rotation
of this distillate as directed in 33 and 34.

40 PINENE.

Chacc Method*. — Tentative.

Mix the 10% distillate, obtained in 39, with 5 cc. of glacial acetic arid; cool the
mixture thoroughly in a freezing bath and add 10 cc. of ethyl nitrite. Then add

266 METHODS OF ANALYSIS [Chap.

slowly, with constant stirring, 2 cc. of hydrochloric acid (2 to 1). Keep the mixture
in the freezing bath 15 minutes. Filter off the crystals formed, using suction, and
wash with 95% alcohol by volume. Return the combined filtrate and washings
to the freezing bath for 15 minutes. Filter off the crystals formed, using the origi-
nal filter paper. Wash the combined crops of crystals thoroughly with alcohol.
Dry at room temperature and dissolve in a minimum amount of chloroform. Add
methyl alcohol to the chloroform solution, a little at a time, until the nitroso-
chlorids crystallize out, mount the separated and dried crystals in olive oil and
examine under the microscope. Pinene nitroso-chlorid crystals have irregular
pyramidal ends while limonene nitroso-chlorid crystallizes in needles.

ALMOND EXTRACT.

41 ALCOHOL— TENTATIVE.

. Inasmuch as almond extract usually contains only about 1% of almond oil
the alcohol can, in most cases, be calculated from the specific gravity of the
extract. If the extract is high in solids, determine the alcohol as follows: Add 25
cc. of the extract, measured at 20°C, to 75 cc. of saturated sodium chlorid solution
in a separatory funnel and extract twice with 50 cc. portions of petroleum ether
(b. p. 40°-60°C.). Collect the petroleum ether extract in a second separatory fun-
nel and wash twice with 2 portions (25 cc.) of saturated brine. Combine the origi-
nal salt solution with the washings; add a little powdered pumice and distil into a
100 cc. flask. When almost 100 cc. have been distilled, make up to the mark with
water at 20°C. and determine alcohol from the specific gravity, as directed under
XVII, 4.

BENZALDEHYDE.— TENTATIVE.

42 REAGENT.

Phenylhydrazin solution. — Add 1.5 cc. of glacial acetic acid to 20 cc. of water and
mix with 1 cc. of phenylhydrazin.

43

DETERMINATION-.

Measure out 2 portions of 10 cc. each of the extract into 300 cc. Erlenmeyer
flasks and add 10 cc. of the phenylhydrazin solution to 1 flask and 15 cc. to the
other. Allow to stand overnight in a dark place, add 200 cc. of water and filter on
a tared Gooch crucible, provided with a thin layer of asbestos. Wash first with cold
water, finally with 10 cc. of 10% alcohol, and dry for 3 hours in a vacuum oven at
70°C, or to constant weight over sulphuric acid. The weight of the precipitate
multiplied by the factor 5.408 gives the weight of benzaldehyde in 100 cc. of the
sample. If duplicate determinations do not agree, repeat the operation using a
larger quantity of the phenylhydrazin solution.

HYDROCYANIC ACID.

44 Qualitative Test. — Tentative.

Add several drops of ferrous sulphate solution and a single drop of ferric chlorid
solution to several cc. of the extract. Mix thoroughly, add sodium hydroxid solu-
tion, drop by drop, until no further precipitate forms and then dilute hydro-
chloric acid to dissolve the precipitated hydroxids. In the presence even of small
amounts of hydrocjranic acid, a Prussian blue coloration or suspension will develop.

XX]

FLAVORING EXTRACTS

267

45 Quantitative Method. — Tentative.

(In the absence of chlorids.)

Measure 25 cc. of the extract into a small flask and add 5 cc. of freshly precipi-
tated magnesium hydroxid (chlorin-free). Titrate with N/10 silver nitrate solu-
tion, using potassium chromate as an indicator; 1 cc. of N/10 silver nitrate is
equivalent to 0.00268 gram of hydrocyanic acid.

46

NITROBENZOL.

Qualitative Test. — Tentative.

Boil a few cc. of the extract with some zinc dust and acetic acid and filter. Add
to the filtrate a drop of chloroform, make strongly alkaline with sodium hydroxid
solution and heat. The presence of nitrobenzol in the original extract is indicated
by the development of the characteristic odor of phenylisonitrile.

CASSIA, CINNAMON AND CLOVE EXTRACTS.
47 ALCOHOL.— TENTATIVE.

Determine as directed under 41 .

48

OIL.

Hortvet and West Method3. — Tentative.

Transfer 10 cc. of the extract to a separatory funnel, add 30 cc. of water, acidify
with 1 cc. of hydrochloric acid (1 to 1) and extract 3 times with ether, using not
less than 100 cc. altogether. Wash the combined ether solutions twice with water
and, in the case of cinnamon extract, dry by shaking with a small amount of granu-
lated calcium chlorid. Transfer to a tared, wide-mouthed weighing bottle and evap-
orate the ether as rapidly as possible on a boiling water bath, rotating the liquid
upon the sides of the bottle in order to rid the residual oil of traces of ether. Weigh
the residue and divide the weight by the specific gravity of the oil in order to ob-
tain the per cent of oil by volume. In the case of clove oil, allow the weighing bottle
to remain in the balance case until the usual film of moisture has evaporated. The
time of weighing, however, should not be delayed over 3 minutes.

Determine the refractive index of the residual oils at 20°C.

Dissolve a drop of the oil in several drops of alcohol and add a drop of ferric
chlorid solution. The following tabulation gives the specific gravity, refractive
index at 20°C. and color reaction with ferric chlorid solution:

OIL

SPECIFIC GRAVITY

REFRACTIVE INDEX
AT 20°C.

COLOR REACTION

WITH FERRIC

CHLORID SOLUTION

1.05
1.03

1.055

1.585-1.600
1.590-1.599
1.560-1.565

Brown

Cinnamon

Cloves

(Jreen
Deep blue

GINGER EXTRACT.

49 ALCOHOL— TENTATIVE.
Determine as directed under XVII, 4.

50 SOLIDS. -TENTATIVE.

Evaporate 10 cc. of the extract nearly to dryness on a water bath, dry for 2 hours
in a water oven and weigh.

268 METHODS OF ANALYSIS [Chap.

GINGER.

51 Seeker Method. — Tentative.

Dilute 10 cc. of the extract to 30 cc, evaporate to 20 cc, decant into a separa-
tory funnel and extract with an equal volume of ether. Allow the ether to evaporate
spontaneously in a porcelain dish, and to the residue add 5 cc. of 75% sulphuric acid
and about 5 mg. of vanillin. Allow to stand 15 minutes and add an equal volume
of water; in the presence of ginger extract an azure blue color develops.

CAPSICUM.

52 La Wall Method Modified by Doyle. — Tentative.

To 10 cc. of the extract add cautiously dilute sodium hydroxid solution until the
solution reacts very slightly alkaline with litmus paper. Evaporate at about 70°C.
to approximately one fourth the original volume, render slightly acid with dilute
sulphuric acid, testing with litmus paper. Transfer to a separatory funnel, rinsing
the dish with water, and extract with an equal volume of ether, avoiding emulsi-
fication by shaking the funnel gently 1-2 minutes. Draw off the lower layer and
wash the ether extract once with about 10 cc. of water. Transfer the washed ether
extract to a small evaporating dish, render decidedly alkaline with N/2 alcoholic
potassium hydroxid and evaporate at about 70°C. until the residue is pasty; then
add about 20 cc. more of N/2 alcoholic potash and allow to stand on a steam bath
until the gingerol is completely saponified (about 30 minutes). Dissolve the residue
in a little water and transfer with water to a small separatory funnel. The volume
should not exceed 50 cc. Extract the alkaline solution with an equal volume of
ether. Wash the ether extract repeatedly with small amounts of water until no
longer alkaline to litmus. Transfer the washed extract to a small evaporating dish,
and allow the ether to evaporate spontaneously. Finally test the residue for capsi-
cum by moistening the tip of the finger, rubbing it on the bottom and side3 of the
dish, and then applying the finger to the end of the tongue. A hot, stinging or
prickly sensation, which persists for several minutes, indicates capsicum or other
foreign pungent substances.

PEPPERMINT, SPEARMINT AND WINTERGREEN EXTRACTS.

53 ALCOHOL.-TENTATIVE.
Proceed as directed under 41 .

OIL.

54 Howard Method10 Modified. — Tentative.

Pipette 10 cc. of the extract into a Babcock milk bottle, add 1 cc. of carbon di-
sulphid, mix thoroughly, then add 25 cc. of cold water and 1 cc. of concentrated
hydrochloric acid. Close the mouth of the bottle and shake vigorously; eentrif-
ugalize for 6 minutes and remove all but 3-4 cc. of the supernatant liquid, which
should be practically clear, by aspirating through a glass tube of small bore.
Connect the stem of the bottle with a filter pump, immerse the bottle in water kept
at approximately 70°C. for 3 minutes, remove from the bath every 15 seconds and
shake vigorously. Continue in the same manner for 45 seconds, using a boiling water
bath. Remove from the bath and shake while cooling. Disconnect from the suc-
tion and fill the bottle to the neck with saturated salt solution at room temperature,
centrifugalize for 2 minutes and read the volume of the separated oil from the top
of the meniscus. Multiply the reading by 2 to obtain the per cent of oil by volume.

XX] FLAVORING EXTRACTS 269

In the case of wintergreen, use as a floating medium a mixture of 1 volume of con-
centrated sulphuric acid and 3 of saturated sodium sulphate solution.

METHYL SALICYLATE IN WINTERGREEN EXTRACT.

55 Hortvet and West Method3 Modified. — Tentative.

Mix 10 cc. of the extract with 10 cc. of 10% potassium hydroxid solution. Heat
on the steam bath until the volume is reduced about one half, add a distinct excess
of hydrochloric acid (1 to 1), cool and extract with 3 portions of ether, 40, 30 and
20 cc, respectively. Filter the extract through a dry filter into a weighed dish, wash
the paper with 10 cc. of ether and allow the filtrate and washings to evaporate spon-
taneously. Dry in a desiccator containing sulphuric acid and weigh. Multiply
the weight of salicylic acid so found by 9.33 to obtain the per cent by volume of
wintergreen oil in the sample.

ANISE AND NUTMEG EXTRACTS.

OIL.

56 Hortvet and West Method9. — Tentative.

To 10 cc. of the extract in a Babcock milk bottle add 1 cc. of hydrochloric acid
(1 to 1), then sufficient half saturated salt solution, previously heated to 60°C, to
fill the flask nearly to the neck. Cork and let stand in water at 60°C. for about 15
minutes, rotate occasionally and centrifugalize for 10 minutes at about 800 revo-
lutions per minute. Add brine till the oil rises into the neck of the bottle, and again
centrifugalize for 10 minutes. If the separation is not satisfactory, or the liquid is
not clear, cool to about 10°C. and centrifugalize for an additional 10 minutes.
Multiply the reading by 2 to obtain the percentage of oil by volume.

BIBLIOGRAPHY.

1 J. Am. Chem. Soc, 1899, 21: 256; 1902, 24: 1128; 1905, 27: 719.

2 U. S. Bur. Chem. Bull. 132, p. 109.

3 Ibid., 152, p. 146.

4 J. Am. Chem. Soc, 1906, 28: 1472.

5 U. S. Bur. Chem. Bull. 132, p. 102.

6 Ibid., 137, p. 72.

7 Schimmel and Co. Semi-annual Report. Oct. 1898, p. 41.

8 U. S. Bur. Chem. Circ 46. p. 9.
3 J. Ind. Eng. Chem., 1909, 1: 84.

10 Ibid., 1911, 3:252.

XXI. MEAT AND MEAT PRODUCTS.
MEAT.

1 PREPARATION OF SAMPLE.— TENTATIVE.

In the case of fresh meat, separate the sample as completely as possible from the
bones and pass through a sausage mill rapidly and repeatedly until thoroughly
mixed and macerated. Chill the sample to prevent decomposition and begin all
determinations as soon as practicable after the sample is prepared.

In the case of canned meats, pass the entire contents of a can through a sausage
mill as directed above. Remove sausage from the casings and mix by repeated
grinding in a sausage mill. Dry the portion of the sample, which is not needed
for analysis, either in vacuo or by evaporating with alcohol, extract the fat with
gasoline (b. p. below 60°C), allow the gasoline to evaporate spontaneously and
expel the last traces by heating for a short time on the steam bath. Do not
heat the meat or separated fat longer than necessary, owing to the tendency of the
latter to decompose. Reserve the fat for examination according to the methods
given under XXIII. Keep the fat in a cool place and complete the examination
before the fat becomes rancid.

2 MOISTURE.— TENTATIVE.

Proceed as directed under VIII, 2 or 3, using the latter method in cases in which
it is desired to employ the dried sample for further determinations.

3 ASH.— OFFICIAL.

Proceed as directed under VIII, 4.

4 CRUDE FAT OR ETHER EXTRACT.-OFFICIAL.

Proceed as directed under VIII, 10.

5 TOTAL PHOSPHORUS.— TENTATIVE.

Destroy the organic matter as directed under I, 5 (a), (b), (C) or (d) and proceed
as directed under I, 6 or 9.

WATER-SOLUBLE PHOSPHORUS1.— TENTATIVE.

6 PREPARATION OF SOLUTIONS.

(a) Cold water extract of flesh. — Weigh out 10-12 grams of fresh muscle and di-
vide equally between 2 small beakers. Moisten the sample with a few cc. of water,
and break up the lumps with a glass rod. Add 50 cc. of water to each beaker and
stir the contents for 15 minutes. Allow the insoluble residue to settle for 3-5 min-
utes, decant the liquid through filters into beakers and add 25 cc. of water to each
residue. Stir 7-8 minutes and, after allowing to settle, decant onto the same filter.
Continue this treatment, using 25 cc. of water each time, until the filtrates measure
about 230 cc. each. Allow the filters to drain completely between extractions.
Whenever the major portion of the residue has been mechanically transferred to the
filter, return it to the beaker. After the last extraction, transfer the entire con-

271

272 METHODS OF ANALYSIS [Chap.

tents of each beaker onto the filter and, when drained, wash twice with small quan-
tities of water. Combine the 2 extracts.

(b) Hot water-ammonium sulphate extract of blood. — Weigh out 30-35 grams of
fresh whole blood as caught from the animal into a porcelain mortar. Grind and
transfer to a 400 cc. beaker with hot water. Make up to about 150 cc. with boil-
ing water. Place over a flame, gradually bring to boiling, with constant stirring,
then add 20 cc. of 20% ammonium sulphate solution and continue boiling, with
constant stirring, for about 10 minutes. Decant onto an 18 cm. filter paper, re-
ceiving the filtrate in an 800 cc. beaker. Transfer the coagulum from the filter,
along with that remaining in the beaker, to a mortar. Grind to a smooth paste
and transfer to a beaker with boiling 3j% ammonium sulphate solution. Make up
to about 50 cc. with the latter, stir for 8 minutes and again filter. Return the
coagulum to the mortar and grind again, transferring to the beaker as before with
boiling 3f% ammonium sulphate solution. Repeat this process of 8 minute extrac-
tions of the coagulum in 3|% ammonium sulphate solution and filtration as directed
above, without further grinding, until the filtrate measures about 450 cc. Wash out
each beaker twice with 8-10 cc. of hot 3J% ammonium sulphate solution, transferring
the coagulum and extract to the filter. Wash the coagulum twice with boiling 3|%
ammonium sulphate solution from a wash bottle. Always allow the filter to drain
well between additions of extract or wash solutions.

(C) Hot waler-ammonium sulphate extract of liver. — Weigh by difference from a
closed weighing bottle 15-20 grams of finely ground liver into a 400 cc. beaker. Add
a few cc. of cold water and beat up with a stirring rod to separate the particles of
tissue. Add enough boiling water to make the volume about 150 cc, place over a
flame and bring to boiling. Add 10 cc. of 20% ammonium sulphate solution and
continue to boil for 10 minutes. Allow to settle for a moment and decant the boil-
ing hot liquid onto an 18 cm. filter. Add 50 cc. of boiling water and stir for 8 min-
utes, without further heating, and decant onto the filter again. Repeat this addi-
tion of 50 cc. of hot water, stirring and decanting 8 times, returning the coagulum
to the beaker as soon as any considerable amount collects upon the filter. With
the eighth portion of water transfer the entire contents of the beaker onto the filter
and wash twice with hot water. Always allow the filter to drain well between
additions of extract or wash water.

(d) Hot water-ammonium sulphate extract of brain. — Weigh out about 10 grams
of brain into a 250 cc. beaker. Add a few cc. of water and work up the brain and
water with a glass rod. Make up to about 100 cc. with boiling water, place over a
flame, and gradually bring to boiling, with constant stirring. While boiling vigor-
ously (not before) add 20 cc. of 20% ammonium sulphate solution, boil gently for
about 10 minutes, allow to settle for a moment and decant slowly onto a linen filter
containing acid-washed, glassmaker's sand, receiving the extract in an 800 cc.
beaker. Add to the beaker containing the coagulum 50 cc. of 3|% ammonium
sulphate solution, stir 1 minute, keep boiling and decant the liquid onto the filter.
Repeat this process of 1 minute extractions of the coagulum in 3|% ammonium
sulphate solution, and filtration as directed above, until the filtrate measures about
450 cc. Wash out the beaker twice with 8-10 cc. of hot 3$%^ ammonium sulphate
solution, completing the transfer of the coagulum and extract to the sand, and wash
the coagulum twice with the wash solution. Always allow the filter to drain well
between additions of extract or wash solution.

In making extracts of brain, give careful attention to the handling of the sample.
The coagulum is very soft. It should be stirred only enough to keep it in motion.
If handled roughly in returning from the sand filter to the beaker, it becomes too

XXI] MEAT AITC) MEAT PRODUCTS 273

finely divided and retains a great deal of liquid. To prevent the extract or the
coagulum from coming into contact with the linen before passing through the sand,
pour the extract slowly into a slight depression in the center of the sand or, better
yet, into a thin film of absorbent cotton, 1^ inches in diameter, laid over a depres-
sion in the sand. The coagulum remains on the cotton and its return to the beaker
is facilitated thereby. If the cotton is not broken up by needless stirring, it can be
taken out of the beaker with a glass rod and returned to the sand each time a partial
extract is to be filtered. Care is necessary to prevent loss through bumping, on
account of sand in the beakers during the final extractions. Each partial extract
should be boiling hot at the time filtration begins.

7 DETERMINATION.

To the extracts, prepared as directed in 6, add 50 cc. of magnesia mixture [I, 4 (C)]
and stir thoroughly. Allow to stand 15 minutes, add 25 cc. of ammonium hy-
droxid (sp. gr. 0.90), cover and allow to stand 3 days. Filter and wash the pre-
cipitate with 2\°70 ammonium hydroxid. Dissolve the precipitate on the filter paper
and that remaining in the beaker in nitric acid (1 to 1) and hot water, receiving
the solution in a 400 cc. beaker. Neutralize with ammonium hydroxid, make slightly
acid with nitric acid, add 5 grams of ammonium nitrate and determine phosphorus
as directed under I, 6.

8 TOTAL NITROGEN.-OFFICIAL.

Proceed as directed under I, 18, 21 or 23, using about 2 grams of the fresh
sample. In the Kjeldahl and Gunning methods digest with sulphuric acid for at
least 4 hours; in the Kjeldahl-Gunning-Arnold method for 2 hours after the mix-
ture has become clear.

9 SOLUBLE AND INSOLUBLE NITROGEN.— TENTATIVE.

Exhaust 7-25 grams of the sample depending upon the water content in the fol-
lowing manner: Weigh into a 150 cc. beaker, add 5-10 cc. of cold (15°C.) ammonia-
free water and stir to a homogeneous paste. Then add 50 cc. of cold water, stir
every 3 minutes for 15 minutes, let stand for 2-3 minutes and decant the liquid upon
a quantitative filter, collecting the filtrate in a 500 cc. graduated flask. Drain the
beaker, pressing out the liquid from the meat residue by the aid of a glass rod.
Add to the residue in the beaker 50 cc. of cold water, stir for 5 minutes and, after
standing 2-3 minutes, decant as before. If a considerable portion of the meat
is carried over onto the filter, transfer it back to the beaker by means of a glass
rod. Repeat the extractions, using the following additional amounts of cold water:
50, 50, 25, 25, 25 and 25 cc. After the last extraction transfer the entire insoluble
portion to the filter and wash with three 10 cc. portions of water, allowing the ma-
terial to drain thoroughly after each addition of water. Dilute to the mark, mix
thoroughly and determine the total soluble nitrogen in a 50 cc. aliquot as directed
under I, 18, 21 or 23. Subtract the percentage of soluble nitrogen from the per-
centage of total nitrogen, 8, to obtain the percentage of insoluble nitrogen. To
obtain the percentage of insoluble protein multiply the percentage of insoluble
nitrogen by 6.25.

10 CONNECTIVE TISSUE NITROGEN.-TENTATrVE.

Exhaust 10 grams of the sample with cold water as directed under 9, and boil the
exhausted residue repeatedly with successive portions of about 100 cc. of water
until the total hot water extract amounts to approximately 1 liter. Filter, concen-
trate and determine nitrogen in the concentrated extract. Multiply the percentage
of nitrogen so obtained by 5.55 to obtain the percentage of nitrogenous substances
of the connective tissue.

274 METHODS OF ANALYSIS [Chap.

11 COAGULABLE PROTEINS.— TENTATIVE.

(For uncooked meat only.)
Measure 150 cc. of the extract, from 9, into a 250 cc. beaker and evaporate to 40
cc. on a steam bath, with occasional stirring. Neutralize to phenolphthalein, then
add 1 cc. of N/1 acetic acid and boil gently for 5 minutes. The coagulum should
separate out at once, leaving a clear liquid. Filter on quantitative paper, wash
the beaker thoroughly 4 times with hot water, taking special care to clean the sides.
Finally wash the coagulum on the filter 3 times, dilute the combined filtrate and
washings to a definite volume and reserve for the determination of proteoses, pep-
tones and gelatin, 12, and creatin, 16. Transfer the coagulum with the paper to a
Kjeldahl flask and remove, with concentrated sulphuric acid, any of the material
adhering to the beaker, taking the usual 25 cc. of acid in 5 cc. portions for this pur-
pose, heating the acid in the beaker on a hot plate and rubbing with a glass rod.
Proceed as directed under 8. Multiply the percentage of nitrogen obtained by 6.25
to obtain the percentage of coagulable proteins.

PROTEOSES, PEPTONES AND GELATIN.

12 Modified Tannin-Salt Method2. — Tentative.

Transfer a 50 cc. aliquot of the filtrate, obtained in 11, to a 100 cc. graduated
flask, add 15 grams of sodium chlorid and 10 cc. of cold water, shake until the so-
dium chlorid has dissolved and cool to 12°C. Add 30 cc. of 24% tannin solution,
cooled to 12°C, fill to the mark with water previously cooled to 12°C, shake and
allow the mixture to stand at a temperature of 12°C. for 12 hours or overnight.
Filter at 12°C, transfer 50 cc. of the filtrate to a Kjeldahl flask and add a few drops
of sulphuric acid. Place the flask in a steam bath, connect with a vacuum pump
and evaporate to dryness. Determine nitrogen in the residue as directed in I, 18,
using 30 cc. of sulphuric acid for the digestion. Conduct a blank determination,
using the same amount of reagents, and correct the result accordingly. Mul-
tiply the corrected result by 2 and deduct the amount of nitrogen as found from the
nitrogen determined in another 50 cc. aliquot of the filtrate from the coagulable
proteins without the tannin-salt treatment; the difference multiplied by 6.25 gives
the percentage of proteoses, peptones and gelatin.

1 3 MEAT BASES.-TENTATIVE.

Deduct from the percentage of total nitrogen, 8, the sum of the percentages of
nitrogen, obtained in the determination of insoluble proteins, 9, coagulable pro-
teins, 11, and proteoses, peptones and gelatin, 12, to obtain the percentage of
nitrogen of the meat bases. Multiply the result by 3.12 to obtain the percentage of
meat bases.

AMMONIA.
Folin Aeration Method3. — Tentative.

14 APPARATUS.

Employ the apparatus illustrated in Fig. 9; A is a wash bottle one fourth full of
10% sulphuric acid; J? is a tube containing the sample; C is a rubber disc and D is a
5 cc. bulb to prevent spray from being carried over into the tube (E) which contains
the standard acid ; F is a safety bottle.

15 DETERMINATION.

Introduce 2-4 grams of the finely divided meat into the tube (B) and add 20 cc.
of ammonia-free water. Place a measured amount of N/25 or N/50 sulphuric or

XXI]

MEAT AND MEAT PRODUCTS

275

hydrochloric acid in tube (E). Then add 1 cc. of saturated potassium oxalate solu-
tion to the sample in tube (B), introduce a few drops of kerosene and finally add
just sufficient saturated potassium carbonate solution to render the mixture alkaline.
Place the tubes in position at once, pass air through the apparatus and titrate the
standard acid in tube (E) at hourly intervals, until ammonia ceases to be given off,
using methyl red, cochineal or congo red as an indicator. If preferred, the ammonia,
collected in tube (E), may also be determined by nesslerizing as directed under
IV, 11.

1 g CREATIN.— OFFICIAL.

Evaporate an aliquot or the remaining portion of the filtrate and washings from
the coagulable proteins, 11, fa portion having been used in 12), to 5-10 cc, transfer
with a minimum amount of hot water to a 50 cc. measuring flask, keeping the volume
below 30 cc, add 10 cc. of 2N hydrochloric acid and mix. Hydrolyze in an auto-

yf^A,

W3S^.

FIG. 9. APPARATUS FOR THE FOLIN AMMONIA DETERMINATION.

clave at 117°-120°C. for 20 minutes, allow the flask to cool somewhat, remove and
chill under running water. Partially neutralize the excess of acid by adding 7.5 cc
of 10% sodium hydroxid solution, free from carbonates, dilute to the mark and
mix. Make a preliminary reading on 20 cc to ascertain the volume to use to obtain
a reading of approximately 8 mm. and transfer to a 500 cc. graduated flask. Add
10 cc of 10% sodium hydroxid solution and 30 cc. of saturated picric acid solution
fl.2%). Mix and rotate for 30 seconds and let stand exactly 4' minutes. Dilute
to the mark at once with water, shake thoroughly and read in a Duboscq colori-
meter, comparing the color with N/2 potassium dichromate solution, set at 8 mm.
If the reading is too high or too low (above 0.5 or below 7 mm.), calculate the
quantity necessary to obtain a reading of about S mm. The strength of the dichro-
mate solution used must be checked against a standard creatin solution. To obtain
the values, divide SI by the reading and multiply by the volume factor to obtain mg.
of creatinin; this value multiplied by 1.16 gives creatin, which, divided by the weight
of the sample and multiplied by 100 gives the per cent of creatin.

276 METHODS OF ANALYSIS [Chap.

The use of Kober's shade and the painting of the plunger, as suggested for this
nephelometer, assists in getting a sharper end point, relieves the eye strain and
may be employed if desired.

Example. — 20 grams of meat are extracted with water as in 9, and the extract
diluted to 500 cc. ; 150 co. of this latter solution (equivalent to 6 grams of meat) are
treated as in 11. The filtrate thus obtained is then evaporated and hydrolyzed as
above and then diluted to 50 cc. ; 25 cc. of this last solution are treated with sodium
hydroxid solution and picric acid solution as directed above and diluted to 500 cc.
This latter solution gives a reading of 9 mm.

-q X 9^=18 nig- creatinin;

0018 X1fX100= 0.35% creatin.

STARCH.
(In chopped meat, sausage, deviled meat, etc.)

17 Qualitative Test. — Tentative.

Treat 5-6 grams of the sample with boiling water for 2-3 minutes, cool the mix-
ture and test the supernatant liquid with iodin solution. In using this test, a small
amount of starch may be present as the result of the use of spices. If a marked
reaction is given, however, it may be concluded that starch or flour has been added,
and a quantitative determination may be made. The qualitative method may be
replaced by a microscopic examination, which discloses not only the presence of
added starch, but also the variety employed.

18 Mayrhofer Method, Price Modification4. — Tentative.

Treat in a 200 cc. beaker 10 grams of the finely divided sample with 75 cc. of an
8% solution of potassium hydroxid in 95% alcohol by volume and heat on a steam
bath until all the meat is dissolved (30-45 minutes). Add an equal volume of 95%
alcohol, cool and allow to stand for at least an hour. Filter by suction through a
thin layer of asbestos in a Gooch crucible. Wash twice with warm 4% potassium
hydroxid in 50% alcohol by volume and then twice with warm 50% alcohol. Dis-
card the washings. Retain as much of the precipitate in the beaker as possible
until the last washing. Place the crucible with contents in the original beaker,
add 40 cc. of water and 25 cc. of concentrated sulphuric acid. Stir during the addi-
tion of the acid and make sure that the acid comes in contact with all the precipi-
tate. Allow to stand about 5 minutes, add 40 cc. of water and heat just to boiling,
stirring constantly. Transfer the solution to a 250 cc. graduated flask, add 2 cc.
of 20% phosphotungstic acid solution, allow to cool to room temperature and make
up to the mark with water. Filter through a starch-free filter paper, pipette 100
cc. of the filtrate into a 200 cc. graduated flask, neutralize with sodium hydroxid
solution, make up to volume and determine the dextrose present in a 50 cc. portion
of the filtrate, as directed under VIII, 25, titrating the cuprous oxid precipitate
as directed under VIII, 29. The weight of the dextrose multiplied by 0.9 gives
the weight of the starch.

GLYCOGEN.

19 Qualitative Tesis. — Tentative

Boil 50 grams of the macerated sample with 50 cc. of water for 15-30 minutes.
Filter the broth through moistened filter paper or fine linen. To a portion of the
filtrate in a test tube add a few drops of a mixture of 2 parts of iodin, 4 of potassium

XXI] MEAT AND MEAT PRODUCTS 277

iodic! and 100 of water. In the presence of a considerable amount of glycogen the
latter produces a dark brown color, which is destroyed by heating and reappears
on cooling. When starch is present, it may be precipitated by treating the water
extract with 2 volumes of glacial acetic acid, filtering and applying the test for
glycogen to the filtrate.

Trowbridge and Francis Method*. — Tentative.

20 PREPARATION OP SOLUTION.

Weigh out by difference about 25 grams of the finely ground and thoroughly
mixed sample. Place in a 400 cc. beaker and mix with 50 cc. of potassium hydroxid
solution (lj to 1), free from carbonate. Cover the beaker with a watch glass and
digest on the water bath for 2 hours, with occasional stirring. At the end of the 2
hours, dilute to approximately 200 cc. with cold water.

Add to the solution an equal volume of 95% alcohol by volume, cover with a
watch glass and set aside for 10-12 hours. Decant the supernatant liquid through a
folded 18.5 cm. filter, allowing the glycogen to remain in the beaker and wash by
decantation with 66% alcohol (2 volumes of 95% alcohol to 1 of water) until the
glycogen is white, or nearly so. Usually about 4 washings are required. Transfer
the washed precipitate from the beaker to the filter and wash 2-3 times with 66%
alcohol. The solution filters slowly and the funnel should be covered with a watch
glass to prevent excessive evaporation. The albuminous substance present retards
the filtration if permitted to dry on the paper. If the washing by decantation is not
made nearly complete, it will be difficult to obtain the glycogen free from the coloring
matter.

After the washing is completed, close the bottom of the funnel by a piece of rub-
ber tubing and a pinch-cock. Fill the funnel with warm water, cover with the watch
glass and let stand 2-3 hours, or overnight. Open the pinch-cock and allow all
of the solution to pass through the filter into a beaker. Close the funnel with the
pinch-cock and fill with warm water as before. Allow this water to remain in the
funnel for an hour and then filter as before. At first the glycogen solution appears
quite turbid. This washing with warm water should be continued until the filtrate
becomes perfectly clear. To the solution of glycogen in water, add double its
volume of 95% alcohol by volume and let stand overnight to complete the repre-
cipitation of the glycogen. Filter and wash as before with 66% alcohol.

21 DETERMINATION.

If desired, the last filtration may be made through a tared Gooch crucible and the
weight of glycogen determined after drying to constant weight. This gives results
that are approximately correct. More satisfactory results are obtained by hydrolyz-
ing the glycogen with dilute hydrochloric acid and determining the resultant dex-
trose. Dissolve the glycogen on the filter in warm water as directed above, collect-
ing the filtrate and washings in a 300 cc. graduated flask and keeping the volume
within 225 cc. Add 12.5 cc. of hydrochloric acid (sp. gr. 1.19) to the combined fil-
trate and washings, mix and place in a boiling water bath for 3 hours. Cool, neu-
tralize with sodium hydroxid solution, cool again, make up to volume with wafer
and determine dextrose in an aliquot of the solution as directed under VIII. 54,
determining the reduced copper as directed under VIII, 29. Multiply the cor-
responding weight of dextrose by 0.9 to obtain its equivalent of glycogen and correct
this result for dilution to obtain the per cent of glycogen in the sample.

278 METHODS OF ANALYSIS [Chap.

SUGAR7.— TENTATIVE.

22 REAGENTS.

(a) Mercuric nitrate solution. — Warm 220 grams of yellow mercuric oxid with
300 cc. of water and treat with small portions of nitric acid, stirring until dissolved.
Make up to 1 liter and filter.

(b) Phosphotungstic acid solution. — Prepare a 20% solution of phosphotungstic
acid in 2.5% hydrochloric acid.

23 DETERMINATION.

Boil 100 grams of the sample with about 350 cc. of water for about 20 minutes,
cool, add an excess (10-30 cc.) of the mercuric nitrate solution, nearly neutralize
with sodium hydroxid solution and make up to 500 cc, exclusive of fat. Mix thor-
oughly, allow the mixture to settle and decant the clear liquid through a large, dry,
folded filter. To an aliquot of the filtrate add 1-2 cc. of concentrated hydrochloric
acid for each 100 cc, heat to boiling and saturate thoroughly with a rapid current
of hydrogen sulphid. Remove the excess of hydrogen sulphid by means of a cur-
rent of air, cool, make up to a definite volume with water and filter. To an aliquot
of the filtrate add an excess of the phosphotungstic acid solution, noting the in-
crease in volume of the solution caused by this addition and place in an ice box
for several hours or overnight. Filter, introduce 50 cc. of the filtrate into a 400 cc.
beaker, neutralize with concentrated sodium hydroxid solution, add 50 cc. of Soxh-
let's solution [VIII, 19], heat so that boiling begins in 4 minutes, boil 2 minutes and
filter through an alundum crucible of suitable porosity, using very gentle suction.
If the filtrate is green or yellow, refilter through the same crucible until the fil-
trate is clear blue. Wash the precipitate with a very small amount of 5% sodium
hydroxid solution, refiltering the washings if they are turbid. Dissolve the precipi-
tated cuprous oxid in nitric acid (1 to 1) and determine copper as directed under
VIII, 29. Find the corresponding amount of dextrose or invert sugar from VIII,
27, and calculate the per cent in the original sample by proper correction for the
various aliquots taken in the determination. To convert invert sugar to sucrose
multiply by the factor 0.95.

NITRATES.

Schlosing-Wagner Method8. — Tentative.

24 REAGENT.

Ferrous chlorid solution. — Dissolve nails or other small pieces of iron in concen-
trated hydrochloric acid, keeping an excess of iron present until the evolution of gas
ceases. Keep the solution in 50 cc. glass-stoppered bottles entirely filled. Employ
only freshly opened bottles of the reagent for the determination.

25

APPARATUS.

Provide a 250 cc. flask with a 2-holed rubber stopper. Through one of the holes
pass the stem of a funnel having a glass stop-cock, and into the other fit a delivery
tube leading downward at an angle from the flask to a trough containing water.
Terminate the upper end of the delivery tube just below the rubber stopper in
the flask and place the lower end under the surface of the water in the trough, the
exit being immediately beneath the mouth of an inverted measuring tube, filled
with 40% potassium hydroxid solution. Cover the trough end of the delivery tube
with a piece of rubber tubing. Midway on the delivery tube between the flask and
the measuring tube place a short length of rubber tubing and a pinch-cock.

XXI ] MEAT AND MEAT PRODUCTS 279

26 DETERMINATION.

Extract 100 grams of finely ground meat by boiling repeatedly with successive
small portions of water, decanting the extracts through a muslin or paper filter
into a casserole, and concentrate the combined extracts to a volume of about 50 cc.

Introduce 50 cc. of the ferrous chlorid solution and 50 cc. of 10% hydrochloric acid
into the flask, close the stop-cock of the funnel, open the pinch-cock on the delivery
tube, move the end of the latter so that escaping air will not pass into the measuring
tube, and boil the contents of the flask until the air is expelled, as indicated by a
slight pressure against the fingers when the rubber tubing is compressed after mo-
mentary removal of the flame. Now close the delivery tube with the pinch-cock
and place the exit end beneath the measuring tube. Introduce the concentrated
extract of the sample into the flask, a little at a time, through the funnel tube,
opening the pinch-cock on the delivery tube and boiling the contents of the flask
at intervals to force the nitric oxid gas into the measuring tube. Finally rinse the
casserole and the funnel tube with a little boiled water, add the rinsings to the con-
tents of the evolution flask in the manner just described and boil until nitric oxid
no longer passes over into the measuring tube. Calculate the volume of nitric
oxid at 0°C. and 760 mm. pressure. One cc. of nitric oxid at 0°C. and 760 mm.
pressure is equivalent to 0.004512 gram of potassium nitrate.

Phenoldisulphonic Acid Method9. — Tentative.

27 REAGENTS.

(a) Phenoldisulphonic acid solution. — Heat 6 grams of phenol with 37 cc. of con-
centrated sulphuric acid on a water bath, cool and add 3 cc. of water.

(b) Standard comparison solution. — Dissolve 1 gram of pure, dry potassium ni-
trate in water and dilute to 1 liter. Evaporate 10 cc. of this solution to dryness
on a steam bath, add 2 cc. of the phenoldisulphonic acid solution, mix quickly and
thoroughly by means of a glass rod, heat for about a minute in a steam bath and
dilute to 100 cc. One cc. of this solution is equivalent to 0.1 mg. of potassium ni-
trate. Prepare a series of standard comparison tubes by introducing amounts
ranging from 1-20 cc. of this solution (0.1-2.0 mg. of potassium nitrate) into 50 cc.
Nessler tubes, adding 5 cc. of strong ammonium hydroxid to each and diluting to
50 cc. These standard tubes are permanent for several weeks if kept tightly
stoppered.

28 DETERMINATION.

Weigh 1 gram of the sample into a 100 cc. flask, add 20-30 cc. of water and heat
on a steam bath for 15 minutes, shaking occasionally. Add 3 cc. of saturated silver
sulphate solution for each per cent of sodium chlorid present, then 10 cc. of basic
lead acetate solution and 5 cc. of alumina cream, shaking after each addition.
Make up to the mark with water, shake and filter through a folded filter, returning
the filtrate to the filter until it runs through clear. Evaporate 25 cc. of the filtrate
to dryness, add 1 cc. of the phenoldisulphonic acid solution, mix quickly and thor-
oughly by means of a glass rod, add 1 cc. of water and 3 or 4 drops of concentrated
sulphuric acid and heat on a steam bath for 2-3 minutes, being careful not to char
the material. Then add about 25 cc. of water and an excess of ammonium hydroxid,
transfer to a 100 cc. graduated flask, add 1-2 cc. of alumina cream if not perfectly
clear, dilute to the mark with water and filter. Fill a 50 cc. Nessler tube to the
mark with the filtrate and determine the amount of potassium nitrate present in

280 METHODS OF ANALYSIS [Chap.

the sample by comparison with the standard comparison tubes. If the solution is
too dark for comparison with the standards, dilute with water and correct the
result accordingly.

29 PRESERVATIVES.— TENTATIVE.

Proceed as directed under X.

30 METALS.— TENTATIVE.
Proceed as directed under XII.

31 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

MEAT EXTRACTS AND SIMILAR PRODUCTS.

32 PREPARATION OF SAMPLE.— TENTATIVE.

Remove liquid and semi-liquid meat extracts and similar preparations from the
container and mix thoroughly before sampling. A little heating expedites the
mixing of pasty extracts. In many liquid preparations a sediment forms which
should be carefully removed from the bottom of the container and included in the
sample. If the sample is in the form of cubes, grind 10-12 of the cubes in a mortar.

33 MOISTURE.— TENTATIVE.

Proceed as directed under VIII, 2, employing about 2 grams of powdered prepa-
rations, about 3 grams of pasty preparations, or 5-10 grams of liquid extracts,
according to the solid content. Dry the powdered preparations directly without
admixture. Dissolve the pasty preparations in water and dry with sufficient ignited
sand, asbestos or pumice stone to absorb the solution. When glycerol is present,
proceed as directed under VIII, 3.

34 ASH.— OFFICIAL.

Proceed as directed under VIII, 4. Add sufficient water to pasty preparations
to effect solution and evaporate to dryness in order that the solids may be distrib-
uted evenly over the bottom of the dish.

35 TOTAL PHOSPHORUS.— TENTATIVE.

Proceed as directed under 5.

3g CHLORIN.— TENTATIVE.

Dissolve about 1 gram of the sample, prepared as directed in 32, in 20 cc. of 5%
sodium carbonate solution and proceed as directed under III, 18.

37 FAT.— TENTATIVE.

Transfer the residue from the determination of moisture to a continuous extrac-
tion apparatus and proceed as directed under VIII, 10.

33 TOTAL NITROGEN.— OFFICIAL.

Proceed as directed under I, 18, 21 or 23.

XXI] MEAT AND MEAT PRODUCTS 281

39 INSOLUBLE PROTEIN10.— TENTATIVE.

Dissolve 5 grams of powdered preparations, 8-10 grams of pasty extracts, or 20-
25 grams of fluid extracts, in cold water. Filter and wash with cold water. Trans-
fer the filter paper and contents to a Kjeldahl flask and determine nitrogen as di-
rected under 1, 1 8, 21 or 23. However, if a large amount of insoluble matter is pres-
ent, transfer the weighed sample to a graduated flask, make up to a definite volume,
shake thoroughly, filter through a folded filter and determine nitrogen in an aliquot
of the filtrate. Deduct the percentage of nitrogen in the total filtrate from the
percentage of total nitrogen, 38, to obtain the percentage of nitrogen in the insol-
uble protein. Multiply this percentage of nitrogen by 6.25 to obtain the percentage,
of insoluble protein.

40 COAGULABLE PROTEIN.— TENTATIVE.

Prepare a solution of the sample as directed in 39. Employ as large an aliquot
of the filtrate as practicable or an aliquot of the filtrate from the insoluble protein, 39,
and neutralize to phenolphthalein by the addition of acetic acid or sodium hydroxid,
whichever may be necessary, add 1 cc. of N/1 acetic acid, boil for 2-3 minutes,
cool to room temperature, dilute to 500 cc. and pass through a folded filter.

Determine nitrogen in 50 cc. of the filtrate as directed under I, 18, 21 or 23.
Ten times the percentage of nitrogen so obtained subtracted from the percentage
of soluble nitrogen (total nitrogen minus the percentage of nitrogen occurring as
insoluble protein) gives the percentage of nitrogen present as coagulable protein.
Multiply this figure by 6.25 to obtain the percentage of coagulable protein in the
sample.

41 AMMONIA.— TENTATIVE.

Mix 1 gram of meat extract with 2 cc. of N/1 hydrochloric acid, wash into a Folin
apparatus with about 5 cc. of water and proceed as directed under 15.

42 PROTEOSES AND GELATIN11.— TENTATIVE.

Evaporate the filtrate from 40 to a small volume and saturate with zinc sulphate
(about 85 grams to 50 cc, avoiding such an excess as would later cause bumping).
Let stand several hours, filter and wash the precipitate with saturated zinc sul-
phate solution, place the filter and precipitate in a Kjeldahl flask and determine ni-
trogen as directed under I, 1 8, 21 or 23. Or, if the precipitate is voluminous, which
rarely happens, make up to a definite volume with saturated zinc sulphate solution,
filter and determine the nitrogen in an aliquot of the filtrate, as directed under I,
18, 21 or 23, and subtract the nitrogen thus obtained from the nitrogen in the
filtrate from the coagulable protein to obtain the nitrogen of the precipitated
protein (proteoses and gelatin).

43 GELATIN— TENTATIVE.

Prepare a 50% solution of the sample, using hot water. Allow to cool and place
in an ice box for 2 hours. If gelatin is present, the solution will set.

The ratio of total creatinin to total nitrogen in a normal meat extract (1 : 1.5)
assists in determining the presence of gelatin or gelatin derivatives. The ratio is
decreased when gelatin or gelatin derivatives are present in any considerable
amount.

282

METHODS OF ANALYSIS

[Chap.

44

AMINO NITROGEN.
Van Slyke Method12. — Tentative.

REAGENTS.

(a) Alkaline permanganate solution. — Dissolve 50 grams of potassium permanga-
nate and 25 grams of potassium hydroxid in sufficient water to make 1 liter.

(b) Sodium nitrite solution. — Dissolve 30 grams of sodium nitrite in sufficient
water to make 100 cc.

(C) Glacial acetic acid.

FIG. 10. VAN SLYKE APPARATUS FOR THE DETERMINATION OF AMINO NITROGEN.

(By courtesy of the Journal of Biological Chemistry.)

45 APPARATUS.

Employ the apparatus shown in Figs. 10 and 11, the former illustrating the man-
ner in which the entire apparatus is arranged and the latter showing the details

XXI]

MEAT AND MEAT PRODUCTS

283

of the deaminizing bulb and connections. The Hempel gas pipette is filled with
the alkaline permanganate solution.

46 DETERMINATION.

Fill with water the burette (F), the capillary tube leading to the Hempel pipette
and also the other capillary as far as c. Introduce into A sufficient glacial acetic
acid to fill one fifth of D, the tube (A) being etched with a mark to measure this

T° Hemppt
P'pekte

FIG. 11. DETAILS OF TIIE DEAMINIZING BULB AND CONNECTION.

{By courtesy of the Journal of Biological Chemistry.)

amount. Allow the acid to run into D, the cock c being turned so as to allow the
air to escape from D. Pour the sodium nitrite solution into A until D is full of solu-
tion and enough excess is present to rise a little above the cock into A. A is also
marked for measuring off this amount. Then close the gas exit from D at c, and,
a being open, shake D for a few seconds until the liquid is forced down to the 20
cc. mark in D. Then close a, open c and shake the apparatus rapidly with the
motor for 2 minutes, these operations being for the purpose of expelling all the air
from D. Then turn c and f so that D and F are connected.

284 METHODS OF ANALYSIS [Chap.

Measure off in B 10 cc. or less, as the case may be, of the solution of the sample
containing not more than 20 mg. of amino nitrogen (about 1-2 grams of the sample)
and allow it to run into D. Connect D with the motor as shown in Fig. 10 and
shake for 5 minutes.

If the solution of the sample is viscous and threatens to foam over, rinse out B,
and then through it introduce a little caprylic alcohol into D, or, if it is known
beforehand that the sample will cause excessive foaming, introduce a little caprylic
alcohol into D through B, rinsing B with alcohol and ether or drying with a roll of
filter paper before adding the solution of the sample.

During the shaking there is an evolution of nitrogen mixed with nitric oxid,the
gases being collected in F. Force all the gas in D into F by opening a and filling
D with liquid from A. Connect F with the Hempel pipette and force the gas into
the latter by means of the leveling bulb, allowing the cock a to remain open during
this and the succeeding operation in order to permit displacement of the liquid in
D by the nitric oxid formed in the interval. Connect the driving rod with the
pipette by lifting the hook from the shoulder of D and placing the other hook, on
the opposite side of the driving rod, over the horizontal lower tube of the pipette.
Shake the pipette rather slowly for a minute which, with any but almost completely
exhausted permanganate solutions, completes the absorption of nitric oxid. Then
return the gas to the burette, adjust the level with the leveling bulb and note the
volume of nitrogen, the temperature and barometric pressure, and calculate the
volume of nitrogen under standard conditions of temperature and pressure. Ob-
tain the corresponding weight of nitrogen, divide the latter by 2, and from the
quotient calculate the apparent per cent of amino nitrogen in the sample. Cor-
rect the result for a blank test performed as above, using 10 cc. of water instead of
the solution of the sample. The amount of gas obtained in the blank is usually
0.3-0.4 cc, and nitrite solutions giving a much larger correction should be
rejected.

In the case of beef extracts and similar preparations 5 minutes is sufficient time
to allow for the completion of the reaction in D. In general the same time serves
for the decomposition of alpha-amino acids but with ammonia, methylamin and
most amines other than alpha-amines 1-1£ hours should be allowed. For determi-
nations on such substances mix the solution of the sample with the reagents as de-
scribed above, allow the mixture to stand in the apparatus till the end of the re-
quired time, and conclude the reaction by shaking the apparatus with the motor for
2-3 minutes. Continue the determination from this point as directed above.

47 ACID ALCOHOL-SOLUBLE NITROGEN13.— TENTATIVE.

Transfer 10 cc. of an aqueous solution of the sample (10 grams of the sample
dissolved in sufficient water to make 100 cc.) or, if the sample is insoluble in water,
1 gram of the sample and 10 cc. of water, to a 200 cc. glass-stoppered measuring
cylinder, add 1.2 cc. of 12% hydrochloric acid, mix and add absolute alcohol to the
200 cc. mark. Mix thoroughly and set aside for several hours. If necessary make
up to volume, filter, transfer 100 cc. of the filtrate to a Kjeldahl flask, evaporate the
alcohol on a water bath and determine nitrogen in the residue as directed under I,

18,21 or 23.

48 CREATIN.- OFFICIAL.

Dissolve about 7 grams of the sample in cold (20°C.) ammonia-free water in a
150 cc. beaker, transfer the solution to a 250 cc. measuring flask, dilute to the mark

XXI] MEAT AND MEAT PRODUCTS 285

and mix thoroughly. Transfer a 20 cc. aliquot of this solution to a 50 cc. meas-
uring flask and proceed as directed under 16. Subtract from the combined creati-
nin value the equivalent of the pre-formed creatinin, 49, and multiply the difference
by 1.16 to convert into creatin. Express the result as per cent of creatin.

49 CREATININ.— OFFICIAL.

For creatinin in beef extract measure about 5 cc. of the solution employed in 48
into a 500 cc. measuring flask, add 10 cc. of 10% sodium hydroxid solution and 30
cc. of the saturated picric acid solution (1.2%), mix and rotate for 30 seconds. Allow
to stand exactly 4| minutes, then dilute to the mark at once with water. Shake
thoroughly and read the depth of color after standing. If the reading is less than
7 or over 9.5 mm., repeat, calculating the quantity of solution necessary to obtain a
reading of about 8 mm. Express the result as per cent of creatinin, making the
calculations as indicated under 16.

GLYCEROL.

50 Cook Method1*.— Tentative.

Weigh 2 grams of a solid or 5 grams of a liquid preparation in a small lead dish or
Hofmeister Schalchen containing 20 grams of ignited sand. Transfer the dish and
its contents to a mortar containing more ignited sand and several grams of anhydrous
sodium sulphate and mix thoroughly. Transfer the mixture, including the dish,
to a Soxhlet apparatus which has a piece of cotton placed in the side arm to prevent
solid particles from being siphoned over. Extract the entire mass with redistilled
anhydrous acetone for 10 hours. Distil the acetone from the extract, carefully re-
moving the last trace by means of a vacuum pump. Take up the residue in water,
add 5 cc. of 10% silver nitrate solution, make up to a volume of 100 cc, shake, allow
to stand overnight, filter and determine glycerol in an aliquot of the filtrate as di-
rected under XIX, 6, beginning at the point "Add * * * 30 cc. of the strong
potassium dichromate solution". With solid meat and yeast extracts a blank of
0.5-1.0 % is obtained in most cases.

51 SUGAR— TENTATIVE.

Heat 20 grams of the sample with about 200 cc. of water on a steam bath until all
soluble substances have gone into solution, cool and proceed from this point as
directed under 23. Reducing sugar up to 0.5% may be present as a natural con-
stituent of meat extracts.

52 PRESERVATIVES.-TENTATIVE.
Proceed as directed under X.

53 METALS.-TENTATIVE.
Proceed as directed under XII.

54 NITRATES.— TENTATIVE.
Proceed as directed under 26 or 28.

286 METHODS OF ANALYSIS

BIBLIOGRAPHY.

1 J. Assoc. Official Agri. Chemists, 1915, 1: 230.

2 J. Am. Chem. Soc, 1906, 28: 1485.

3 J. Assoc. Official Agri. Chemists, 1915, 1: 174.

4 U. S. Bur. Chem. Bull. 162, p. 97.

5 Abs. Z. Nahr. Hyg. Waar., 1896, 10: 173.

6 J. Ind. Eng. Chem., 1910, 2: 21, 215.

7 J. Assoc. Official Agri. Chemists, 1915, 1: 177.

8 Tiemann. Anleitung zur Untersuchung von Wasser. 1870, p. 56; Wiley. Prin-
ciples and Practice of Agricultural Analysis. 2nd ed., 1906-14, 2: 397; U. S. Bur.
Chem. Bull. 13 (X), p. 1403.

9 U. S. Bur. Chem. Bull. 13 (X), p. 1405.

10 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 8: 407.

11 Z. anal. Chem., 1895, 34: 562; U. S. Bur. Chem. Bull. 54.

12 J. Biol. Chem., 1911, 9: 185; 1912, 12: 275; 1913, 16: 121; 1915, 23: 407.

13 J. Am. Chem. Soc, 1914, 36: 1551.

14 J. Assoc. Official Agri. Chemists, 1915, 1: 279.

XXII. DAIRY PRODUCTS.

MILK.

1 SOLIDS.— OFFICIAL.

Heat 3-5 grams of the milk at the temperature of boiling water until it ceases
to lose weight, using a tared, flat-bottomed dish of not less than 5 cm. diameter.
If desired, previously place 15-20 grams of pure, dry sand in the dish. Cool in a
desiccator and weigh rapidly to avoid absorption of hrygroscopic moisture.

2 ASH.— OFFICIAL.

Weigh about 20 grams of the milk in a tared dish, add 6 cc. of nitric acid, evap-
orate to dryness and ignite at a temperature just below redness until the ash is free
from carbon.

3 TOTAL NITROGEN.-OFFICIAL.

Place about 5 grams of the milk in a Kjeldahl digestion flask and proceed, without
evaporation, as directed under I, 18, 21 or 23. Multiply the percentage of nitro-
gen by 6.38 to obtain the equivalent percentage of nitrogen compounds.

CASEIN.

(This determination should be made while the milk is fresh, or nearly so.
When it is not practicable to make this determination within
24 hours, add 1 part of formaldehyde to 2500
parts of milk and keep in a cool place.)

4 Method I.— Official.

Place 10 grams of the milk in a beaker with 90 cc. of water at 40°-42°C. and add
at once 1.5 cc. of 10% acetic acid. Stir and let stand 3-5 minutes. Then decant-
on a filter, wash by decantation 2-3 times with cold water and transfer the precipi-
tate to the filter. Wash once or twice on the filter. The filtrate should be clear,
or very nearly so. If the first portions of the filtrate are not clear, repeat the fil-
tration, after which complete the washing of the precipitate. Determine nitrogen
in the washed precipitate and filter paper as directed under I, 18, 21 or 23, mul-
tiply by 6.38 and calculate the percentage of casein.

In samples of milk which have been preserved, the acetic acid should be added
in small portions, a few drops at a time, with stirring, and the addition continued
until the liquid above the precipitate becomes clear, or very nearly so.

5 Method II— Official.

To 10 grams of the milk add 50 cc. of water at 40°C, then 2 cc. of alum solution
saturated at 40°C, or higher. Allow the precipitate to settle, transfer to a filter
and wash with cold water. Determine nitrogen in t he precipitate and alter paper
as directed under I, 18, 21 or 23, multiply by 6.38 and calculate the percent-
age of casein.

287

288

METHODS OF ANALYSIS

[Chap.

ALBUMIN.

6 Method I. — Tentative.

Exactly neutralize the filtrate, obtained in 4, with sodium hydroxid solution,
add 0.3 cc. of 10% acetic acid and heat on a steam bath until the albumin is com-
pletely precipitated. Collect the precipitate on a filter, wash with cold water and
determine the nitrogen as directed under I, 18, 21 or 23. multiply by 6.38 and cal-
culate the percentage of albumin.

7 Method II. — Tentative.

To the filtrate obtained from the casein determination, 5, add 0.3 cc. of 10% acetic
acid, boil until the albumin is completely precipitated and proceed as directed in 6.

8

LACTOSE.

Optical Method. — Tentative.

REAGENTS.

(a) Acid mercuric nitrate solution. — Dissolve mercury in double its weight of
nitric acid (sp. gr. 1.42) and dilute with an equal volume of water.

(D) Mercuric iodid solution. — Dissolve 33.2 grams of potassium iodid and 13.5
grams of mercuric chlorid in 20 cc. of glacial acetic acid and 640 cc. of water.

9 DETERMINATION.

Determine the specific gravity of the milk by means of a delicate hydrometer
or, if preferred, a pycnometer. The quantity of sample to be taken for the deter-
mination varies with the specific gravity and is to be measured at the same tempera-
ture at which the specific gravity is taken. The volume to be measured will be
found in 10 which is based upon twice the normal weight of lactose (32.9 grams per
100 metric cc.) for the Ventzke sugar scale.

Place the quantity of milk indicated in 10 in a flask graduated at 102.6 cc. Add
1 cc. of the acid mercuric nitrate solution or 30 cc. of the mercuric iodid solution
(an excess of these reagents does no harm), fill to the mark, shake, filter through a
dry filter and polarize. It is not necessary to heat before polarizing. If a 200 mm.
tube is used, divide the polariscope reading by 2 (or, if a 400 mm. tube is used, by 4)
to obtain the per cent of lactose in the sample.

Table 19.
10 Volumes of milk corresponding to a lactose double normal weight1.

VOLUME OF MILK FOP. A

VOLUME of milk for a

SPECIFIC GRAVITY OF

LACTOSE DOUBLE NOR-

SPECIFIC GRAVITY OF

LACTOSE DOUBLE NOR-

MILK

MAL WEIGHT

MILK

MAL WEIGHT

(ventzke scale)

\ ;:ntzke scale)

CC.

cc.

1.024

64.25

1.030

63.90

1.025

64.20

1.031

63. SO

1.026

64.15

1.032

63.75

1.027

64.05

1.033

63.70

1.028

64.00

1.034

63.65

1.029

63.95

1.035

63.55

1.036

63.50

XXII] DAIRY PRODUCTS 289

1 1 Gravimetric Method. — Official.

Dilute 25 grams of the milk with 400 cc. of water in a 500 cc. graduated flask,
add 10 cc. of copper sulphate solution [VIII, 19 (a)] and about 7.5 cc. of a potas-
sium hydroxid solution of such strength that 1 volume is just sufficient to pre-
cipitate completely the copper as hydroxid from 1 volume of the copper sulphate
solution. Instead of potassium hydroxid solution of this strength, 8.8 cc. of N/2
sodium hydroxid solution may be used. After the addition of the alkali solution
the mixture must still have an acid reaction and contain copper in solution. Fill
the flask to the 500 cc. mark, mix, filter through a dry filter and determine lactose
in an aliquot of the filtrate as directed under VIII, 46 or 48.

FAT.

12 Roese-Gottlieb Method2. — Official.

Weigh 10-11 grams of the milk into a Rohrig tube or some similar apparatus,
add 1.25 cc. of concentrated ammonium hydroxid (2 cc. if the sample is sour) and
mix thoroughly. Add 10 cc. of 95% alcohol by volume and mix well. Then add
25 cc. of washed ether and shake vigorously for 30 seconds, then 25 cc. of petro-
leum ether (redistilled slowly at a temperature below 60°C.) and shake again for
30 seconds. Let stand 20 minutes, or until the upper liquid is practically clear.
Draw off as much as possible of the ether-fat solution (usually 0.5-0.8 cc. will be left)
into a weighed flask through a small, quick-acting filter. The flask should always
be weighed with a similar one as a counterpoise. Re-extract the liquid remain-
ing in the tube, this time with only 15 cc. of each ether, shake vigorously 30 seconds
with each and allow to settle. Draw off the clear solution through the small filter
into the same flask as before and wash the tip of spigot, the funnel and the filter
with a few cc. of a mixture of the 2 ethers in equal parts. For absolutely exact
results the re-extraction must be repeated. This third extraction yields usually
not more than about 1 mg. of fat (about 0.02% on a 4 gram charge) if the previous
ether-fat solutions have been drawn off closely. Evaporate the ethers slowly on a
steam bath, then dry the fat in a boiling water oven to constant weight.

Confirm the purity of the fat by dissolving in a little petroleum ether. Should
a residue remain, remove the fat completely with petroleum ether, dry the residue,
weigh and deduct the weight. Finally correct this weight by a blank determina-
tion on the reagents used.

Babcock Method. — Official.

13 APPARATUS.

(a) Standard Babcock test bottles. — The standard Babcock test bottles for milk
and cream shall be as follows:

(1) 8%, 18 gram, 6 inch milk test bottle. — The total per cent graduation shall be 8.
The total height of the bottle shall be 150-165 mm. (5J-6i inches). The capac-
ity of the bulb up to the junction with the neck shall be not less than 45 cc. The
graduated portion of the neck shall have a length of not less than 63.5 mm. 2\
inches) and the neck shall be cylindrical for at least 9 mm. below the lowest and
above the highest graduation marks. The graduations shall represent whole per
cents, halves and tenths of a per cent.

(2) 50%, 9 gram, 6 inch cream test bottle. — The total per cent graduation shall
be 50. The total height of the bottle shall be L50-165 mm. <■">; 6j inches). The
capacity of the bulb up to the junction with the neck shall be not less t ban 45 CC. The
graduated portion of the neck shall have a length of not less than 63.5 mm. 2\

290 METHODS OF ANALYSIS [Chap.

inches) and the neck shall be cylindrical for at least 9 mm. below the lowest and
above the highest graduation marks. The graduations shall represent five per cents,
whole and halves of a per cent.

(3) 50%, 9 gram, 9 inch, cream test bottle. — Same as (2) except that the total height
of the bottle shall be 210-225 mm. (8J-8J inches).

(b) Centrifuge.

(C) Pipettes. — Graduated to deliver 17.6 cc. of water at 20°C. in 5-8 seconds.

(d) Graduates. — Capacity 17.5 cc. or a Swedish acid bottle delivering that amount.

14

CALIBRATION OF APPARATUS.

(a) Graduation. — The unit of graduation for all Babcock glassware shall be the
true cc. (0.998877 gram of water at 4°C).

With bottles, the capacity of each per cent on the scale shall be 0.20 cc.

With pipettes and graduates, the delivery shall be the intent of the graduation;
and the graduation shall be read with the bottom of the meniscus in line with the
mark.

• (b) Testing. — The method for testing Babcock bottles shall be calibration with
mercury (13.5471 grams of clean, dry mercury at 20°C, to be equal to 5% on the
scale), the bottle being previously filled to zero with mercury.

The mercury and cork, alcohol and burette, and alcohol and brass plunger
methods may be employed for the rapid testing of Babcock bottles, but the accuracy
of all questionable bottles shall be determined by calibration with mercury.

The method for testing pipettes and graduates shall be calibration by measuring
in a burette the quantity of water (at 20°C.) delivered.

(C) Limit of error. — For standard Babcock milk bottles the error at any point
of the scale shall not exceed 0.1%.

For standard Babcock cream bottles the error at any point of the scale shall not
exceed 0.5 %.

For standard milk pipettes the error shall not exceed 0.05 cc.

For acid measures the error shall not exceed 0.2 cc.

15

DETERMINATION.

Pipette 17.6 cc. of the carefully mixed sample into a test bottle and add 17.5
cc. of commercial sulphuric acid (sp. gr. 1.82-1.83'. Mix and, when the curd is
dissolved, centrifugalize for 4 minutes at the required speed for the machine used.
Add boiling water, filling to the neck of the bottle, and whirl for 1 minute; again
add boiling water so as to bring the fat within the scale on the neck of the bottle,
and, after whirling for 1 minute more, read the length of the fat column, making the
reading at 57°-60°C. at which temperature the fat is wholly liquid. The reading
gives directly the per cent of fat in the milk.

Details of the manipulation of the Babcock test and its application in the analy-
sis of dairy products other than milk are described by Farrington and Woll3, and
Van Slyke4.

Added Water.

(In conjunction with the copper, acetic or sour serum refraction method,

the determination of the ash of the sour scrum or of the acetic serum

should be made in all cases where the indices of refraction

fall below the minimum limit so as to eliminate

all possibility of abnormal milk.)

XXII] DAIRY PRODUCTS 291

•Jg ACETIC SERUM.— TENTATIVE.

(a) Zeiss immersion refractometer reading. — To 100 cc. of milk at a temperature
of about 20°C. add 2 cc. of 25% acetic acid (sp. gr. 1.035) in a beaker and heat the
mixture, covered with a watch glass, in a water bath for 20 minutes at a tempera-
ture of 70°C. Place the beaker on ice water for 10 minutes and separate the curd
from the serum by filtering through a 12.5 cm. folded filter. Transfer about 35 cc.
of the serum to 1 of the beakers that accompanies the control-temperature bath
used in connection with the Zeiss immersion refractometer, and take the refrac-
tometer reading at exactly 20°C, using a thermometer graduated to tenths of a
degree. A reading below 39 indicates added water; between 39 and 40, the addition
of water is suspected.

(b) Ash. — Transfer 25 cc. of the serum to a flat-bottomed platinum dish and
evaporate to dryness on a water bath. Then heat over a low flame (to avoid spat-
tering) until the contents are thoroughly charred, place the dish in an electric
muffle, preferably with pyrometer attached, and ignite to a white ash at a tem-
perature not greater than 500°C. (900°F.). Cool and weigh. Express the result
as grams per 100 cc. Results below 0.715 gram per 100 cc. indicate added water.
Multiply by the factor 1.021 (dilution of the acetic serum being 2%) to obtain the
result on the sour serum ash.

•J 7 SOUR SERUM.— TENTATIVE.

(a) Zeiss immersion refractometer reading. — Allow the milk to sour spontane-
ously, filter and determine the immersion refractometer reading of the clear serum
at 20°C. A reading below 38.3 indicates added water.

(b) Ash5. — Determine the ash in 25 cc. of the serum, obtained in (a), as directed
in 16 (b). Results below 0.730 gram per 100 cc. indicate added water.

18 ZEISS REFRACTOMETER READING OF COPPER SERUM.— TENTATIVE.

To 1 volume of copper sulphate solution (72.5 grams of copper sulphate per
liter, adjusted if necessary to read 36 at 20°C. on the scale of the Zeiss immersion
refractometer, or, to a specific gravity of 1.0443 at -jr-') add 4 volumes of milk.
Shake well and filter. Determine the Zeiss refractometer reading of the clear
serum at 20°C. A reading below 36 indicates added water.

GELATIN.

19 Qualitative Test. — Tentative.

To 10 cc. of the milk add an equal volume of acid mercuric nitrate solution (mer-
cury dissolved in twice its weight of nitric acid (sp. gr. 1.42) and this solution
diluted to 25 times its volume with water), shake the mixture, add 20 cc. of water,
shake again, allow to stand 5 minutes and filter. If much gelatin is present, the
filtrate will be opalescent and cannot be obtained quite clear. To a portion of the
filtrate contained in a test tube, add an equal volume of saturated aqueous picric
acid solution. A yellow precipitate will be produced in the presence of any con-
siderable amount of gelatin, while smaller amounts will be indicated by a cloudi-
ness. In the absence of gelatin the filtrate will remain perfectly clear.

20 PRESERVATIVES.-TENTATIVE.

Proceed as directed under X. To test for salicylic or benzoic acid acidify 100
cc. of the milk with 5 cc. of hydrochloric acid (] to 3), shake until curdled, filter
and treat the clear tilt rate as directed under X, 2. 3 or 8.

292 METHODS OF ANALYSIS [Chap.

To test for formaldehyde proceed as directed under X, 17, 18, 19, 20, 21, 22,

or 23, applying the test directly to the milk.

COLORING MATTERS.

21 Leach Method. — Tentative.

Warm about 150 cc. of milk in a casserole over a flame and add about 5 cc. of
acetic acid, then slowly continue the heating nearly to the boiling point while stir-
ring. Gather the curd, when possible, into one mass with a stirring rod and pour
off the whey. If the curd breaks up into small flecks, separate from the whey by
straining through a sieve or colander. Press the curd free from adhering liquid,
transfer to a small flask and macerate for several hours, preferably overnight, in
about 50 cc. of ether, the flask being tightly corked and shaken at intervals. De-
cant the ether extract into an evaporating dish, remove the ether by evaporation
and test the fatty residue for annatto as directed in XI, 24.

The curd of an uncoloredmilk is perfectly white after complete extraction with
ether, as is also that of a milk colored with annatto. If the extracted fat-free curd
is distinctly colored an orange or yellowish color, a coal tar dye is indicated. In
many cases upon treating a lump of a fat-free curd in a test tube with a little strong
hydrochloric acid the color changes to pink, indicating the presence of a dye simi-
lar to aniline yellow or butter yellow or perhaps one of the acid azo yellows or
oranges. In such cases, separate and identify the coloring matter present in the
curd as directed under XI. If aniline yellow, butter yellow, or other oil-soluble
dye is present, the greater part will be found in the ether extract containing the
fat. In such cases proceed as directed under XI, 3.

In some cases the presence of coal tar dyes can be detected by treating about
10 cc. of the milk directly with an equal volume of hydrochloric acid (sp. gr. 1.20)
in a porcelain casserole, giving the dish a slight rotary motion. In the presence of
some dyes the separated curd acquires a pink coloration.

CREAM.

22 SOLIDS.-OFFICIAL.

Proceed as directed in 1 , employing 2-3 grams of the sample.

23 ASH.— OFFICIAL.
Proceed as directed under 2.

24 TOTAL NITROGEN.-OFFICIAL.

Proceed as directed under 3.

LACTOSE.

25 Gravimetric Method. — Official.

Proceed as directed under 1 1 .

FAT.

26 Extraction Method. — Official.

Weigh 4-5 grams of the homogeneous sample into a Rohrig tube or similar appa-
ratus, dilute with water to about 10.5 cc. and proceed as directed under 12.

27 Babcock Method. — Official.

Weigh 9 or 18 grams, depending upon the fat content of the sample, into a stand-
ard Babcock cream bottle and proceed as directed under 1 5.

XXII] DAIRY PRODUCTS 293

28 GELATIN.— TENTATIVE.
Proceed as directed under 19.

29 COLORING MATTERS.— TENTATIVE.

Proceed as directed under XI, particularly 3 and 24 for the detection of oil-
soluble coal tar dyes and annatto.

30 PRESERVATIVES.— TENTATIVE.
Proceed as directed under X.

31 CONDENSED MILK (UNSWEETENED).

Dilute 40 grams of the homogeneous sample with 60 grams of water and pro-
ceed as directed under 1 to 15, inclusive, 19, 20 and 21, correcting the results for
the dilution.

CONDENSED MILK (SWEETENED).

32 PREPARATION OF SAMPLE.— OFFICIAL.

If cold, place the can in water at 30°-35°C. until warm. Open, scrape out all
milk adhering to the interior of the can and mix by transferring the contents to a
dish sufficiently large to stir thoroughly and make the whole mass homogeneous.
Weigh 100 grams into a 500 cc. flask and make up to the mark with water. If the
milk will not dissolve completely, weigh out each portion for analysis separately.

33 TOTAL SOLIDS.— OFFICIAL.

Use 10 cc. of the solution, prepared as directed in 32, and proceed as directed in
1, drying either on sand or asbestos fiber.

34 ASH.— OFFICIAL.

Evaporate 10 cc. of the solution, prepared as directed in 32, to dryness on a
water bath and ignite the residue as directed under VIII, 4.

35 PROTEIN.— OFFICIAL.

Determine nitrogen as directed under I, 18, 21 or 23, using 10 cc. of the solu-
tion, prepared as directed in 32, without evaporation and multiply by 6.38.

36 LACTOSE.-OFFICIAL.

Dilute 100 cc. of the solution, prepared as directed in 32, in a 250 cc. flask to
about 200 cc, add 6 cc. of Fehling's copper sulphate solution [VIII, 19 (a)] and make
up to the mark. Filter through a dry filter and determine lactose aa directed in

VIII, 46 or 48.

37 FAT OR ETHER EXTRACT.

Roese-Gottlicb Method. — O^fficial.

Weigh 1-5 grams of the homogeneous sample into a Rohrig tube or some similar
apparatus, dilute with water to about 10.5 cc. and proceed as directed under 12.

38 SUCROSE.-TENTATIVE.

Determine sucrose by difference, deducting the milk solids (lactose, protein, fat
and ash) from the total solids.

294 METHODS OF ANALYSIS [Chap.

BUTTER AND ITS SUBSTITUTES.

39 PREPARATION OF SAMPLE.- OFFICIAL.

If large quantities of butter are to be sampled, use a butter trier or sampler.
Melt completely the portions thus drawn, 100-500 grams, in a closed vessel at as
low a temperature as possible. When softened, cool and, at the same time, shake
the mass violently until it is homogeneous and solidified sufficiently to prevent the
separation of the water and fat. Then pour a portion into the vessel from which
it is to be weighed. The sample should completely or nearly fill the vessel and
should be kept in a cool place until analyzed.

40 MOISTURE.-OFFICIAL.

Weigh 1.5-2.5 grams of the sample into a flat-bottomed dish, having a surface
of at least 20 sq. cm., dry at the temperature of boiling water and weigh at hourly
intervals until the weight becomes constant. The use of clean, dry sand or asbestos
is admissible.

ETHER EXTRACT.

41 Indirect Method. — Official.

Dissolve the dry butter, obtained in the moisture determination in which no
absorbent was used, in absolute ether or petroleum ether, transfer to a weighed
Gooch, with the aid of a wash bottle filled with the solvent and wash until free
from fat. Dry the Gooch and contents at the temperature of boiling water until
the weight is constant and determine the fat.

42 Direct Method.— Official.

From the dry butter, obtained in the determination of moisture, either with or
without the use of an absorbent, extract the fat with anhydrous, alcohol-free ether,
receiving the solution in a weighed flask. Evaporate the ether, dry the extract at
the temperature of boiling water and weigh at hourly intervals until the weight
is constant.

43 CASEIN, ASH AND CHLORIN.-OFFICIAL.

Cover the crucible, containing the residue from the fat determination by the
indirect method, 41, and heat gently at first, then raise the temperature gradually
to just below redness. The cover may then be removed and heating continued
until the contents of the crucible are white. The loss in weight represents casein,
and the residue in the crucible, mineral matter. Dissolve this mineral matter in
water slightly acidified with nitric acid and determine chlorin, either gravimetri-
cally as directed under I, 16 (a), or volumetrically as directed under III. 15.

44 SALT.-OFFICIAL.

Weigh in a counterpoised beaker 5-10 grams of butter, using portions of about
1 gram from different parts of the sample. Add about 20 cc. of hot water and, after
the butter is melted, transfer the whole to a separatory funnel. Insert the stopper
and shake for a few moments. Let stand until all the fat has collected on the top
of the water, then draw off the latter into a flask, being careful to let none of the
fat globules pass. Again add hot water, rinsing the beaker, and repeat the extrac-
tion 10-15 times, using 10-20 cc. of water each time. The washings will contain all
but a mere trace of the sodium chlorid originally present in the butter. Determine
the amount in the whole or an aliquot of the liquid by titration with standard silver
nitrate, using potassium chromate as an indicator.

xxii] dairy products 295

Fat.

45 preparation of sample.— official.

Melt the butter and keep in a dry place at about 60°C. for 2-3 hours or until the
water and curd have entirely separated. Filter the clear, supernatant fat through
a dry filter paper in a hot water funnel or in an oven at about 60°C. If the filtered
liquid fat is not perfectly clear, refilter.

46 EXAMINATION.
Proceed as directed under XXIII.

47 Microscopic Method. — Official.

Place on a slide a small portion of the fresh, unmelted sample taken from the
inside of the mass, add a drop of pure olive oil, apply a cover-glass with gentle
pressure, and examine with a magnification of 120-150 diameters for crystals of
lard, etc. Examine the same specimen with polarized light and a selenite plate
without the use of oil. Pure fresh butter will show neither crystals nor a parti-
colored field with selenite. Renovated butter or other fats melted and cooled and
mixed with butter will usually present crystals and variegated colors with the
selenite plate.

For further microscopic study dissolve in a test tube 3-4 cc. of the fat in 15 cc.
of ether. Close the tube with a loose plug of cotton wool and allow to stand 12-24
hours at 20°-25°C. When crystals form at the bottom of the tube, remove with a
pipette, glass rod or tube, place on a slide, cover and examine under a microscope.
The crystals formed by later deposits may be examined in a similar way. Com-
pare with crystals obtained in the same way from samples of known purity.

48 PRESERVATIVES.-TENTATIVE.
Proceed as directed under X.

49 COLORING MATTERS.-TENTATIVE.

Pour about 2 grams of the filtered fat, dissolved in ether, into each of 2 test tubes.
Into one of the tubes pour 1-2 cc. of hydrochloric acid and into the other about the
same volume of dilute potassium hydroxid solution. Shake the tubes well and
allow to stand. In the presence of azo dyes the test tube to which the acid has been
added will show a pink to wine-red coloration, while the potash solution in the
other tube will show no color. If, on the other hand, annatto or other vegetable
color has been used, the potash solution will be colored yellow, while no color will
be apparent in the acid solution.

General test. — Proceed as directed under XI, particularly 3 and 24, for the detec-
tion of oil-soluble coloring matters and annatto.

RENOVATED BUTTER AND OLEOMARGARINE.

50 Foam Test.—Tenlalirr.

Heat 2-3 grams of the sample, either in a spoon or dish, over a free Same. True
butter will foam abundantly, whereas process butter will bump and sputter, like
hot grease, without foaming. Oleomargarine behaves like process butter, hut
chemical tests will determine whether the .sample is oleomargarine or butter.

296 METHODS OF ANALYSIS [Chap.

51 Melted Fat Test.— Tentative.

Melt 50-100 grams of butter or renovated butter at 50°C. The curd from butter
will settle, leaving a clear supernatant fat; in the case of renovated butter, the
supernatant fat remains more or less turbid.

CHEESE.

52 SELECTION AND PREPARATION OF THE SAMPLE.-OFFICIAL.

When the cheese can be cut, take a narrow, wedge-shaped segment reaching
from the outer edge to the center of the cheese. Cut this into strips and pass 3
times through a sausage machine. When the cheese cannot be cut, take the sample
with a cheese trier. If only 1 plug can be obtained, take it perpendicular to the
surface of the cheese at a point one third the distance from the edge to the center
and extending either entirely or half way through it. When possible, draw 3 plugs,
1 from the center, 1 from a point near the outer edge, and 1 from a point half way
between the other 2. For inspection purposes reject the rind but for investigations
requiring the absolute amount of fat in the cheese include the rind in the sample.
Either grind the plugs in a sausage machine or cut them very finely and mix carefully,
preferably the former.

53 MOISTURE.— TENTATIVE.

Place 2-3 grams of very short fiber asbestos (the long fiber may be made suit-
able by rubbing it through a fine sieve) in a flat-bottomed platinum dish, 6-7 cm.
in diameter, and press the asbestos down firmly. Place in the dish a glass rod,
about 5 mm. in diameter and slightly longer than the diameter of the dish. Ignite,
cool and weigh the dish and contents. Then weigh into the dish 4-5 grams of the
sample, prepared as directed under 52, and mix the cheese and asbestos intimately
with the glass rod until the mass is homogeneous. Leave the mass in as loose a con-
dition as possible to facilitate the drying. Dry the mixture in an oven at 100°C.
and weigh at 1-1 5 hour intervals until the weight becomes constant (3 weighings are
usually sufficient).

54 ASH AND SALT.— OFFICIAL.

The dry residue from the moisture determination may be used for the determi-
nation of ash. If the cheese be rich in fat, the asbestos will be saturated with it.
Ignite cautiously to avoid spattering and remove the lamp while the fat is burn-
ing off. When the flame has died out, complete the burning in a muffle at low red-
ness. When desired, the salt may be determined in the ash, as directed in 43.

55 NITROGEN.— OFFICIAL.

Determine nitrogen as directed under I, 18, 21 or 23, using about 2 grams of
cheese, and multiply the percentage of nitrogen by 0.3S to obtain the per cent
of nitrogen compounds.

56 ACIDITY.— TENTATIVE.

To 10 grams of finely divided cheese add water at a temperature of 40°C. until
the volume equals 105 cc, shake vigorously and filter. Titrate 25 cc. portions of
the filtrate, representing 2.5 grams of the sample, with standard sodium hydroxid,
preferably N/10, using phenolphthalein as an indicator. Express the result in
terms of lactic acid.

XXII] DAIRY PRODUCTS 297

57 COLORING MATTERS.— TENTATIVE.
Proceed as directed under XI.

Fat.

58 preparation of sample.— tentative.

(a) Alkaline extraction. — Treat about 300 grams of the cheese, cut into frag-
ments the size of a pea, with 700 cc. of 5% potassium hydroxid solution at 20°C. in
a large, wide-necked flask, shaking vigorously to dissolve the casein. In 5-10
minutes the casein will be dissolved and the fat will rise to the surface in lumps.
Collect the lumps of fat into as large a mass as possible by shaking gently. Pour
cold water into the flask until the fat is driven up into the neck and remove it by
suitable means. Wash the fat thus obtained with just sufficient water to remove
the residue of the alkali which it may contain. The fat is not perceptibly attacked
by the alkali in this treatment, is practically all separated in a short time and is then
easily prepared for chemical analysis by filtering and drying as directed in 45.

(b) Acid extraction. — Pass the cheese through a grinding machine, transfer to a
large flask and cover with warm water, using 1 cc. for every gram of cheese. Shake
thoroughly and add sulphuric acid (sp. gr. 1.82-1.825) slowly and in small quanti-
ties, shaking after each addition of acid. The total amount of acid used should
be the same as the amount of water employed. Remove the fat, which separates
after standing a few minutes, by means of a separatory funnel, wash free from acid,
filter and dry as directed in 45.

59 EXAMINATION.— TENTATIVE.
Proceed as directed under XXIII.

Estimation.

60 Gravimetric Method. — Official.

Cover the perforations in the bottom of an extraction tube with dry asbestos
felt, and place on this a mixture containing equal parts of anhydrous copper sul-
phate and pure, dry sand to a depth of about 5 cm., packing loosely. Cover the
upper surface of this material with a layer of asbestos. Place on this 2-5 grams of
the sample and extract with anhydrous ether for 5 hours in a continuous extrac-
tion apparatus. Remove the cheese and grind it with pure sand in a mortar to a
fine powder, return the mixed cheese and sand to the extraction tube, wash the mor-
tar with ether, add the washings to the tube and continue the extraction for at least
10 hours.

61 Schmidt-Bondzynski Method, Modified. — Tentative.

Rub up, by means of a glass rod, 1 gram of the homogeneous sample with 9 cc. of
water and 1 cc. of concentrated ammonium hydroxid in a narrow 100-125 cc. beaker.
Digest the mixture at a low heat until the casein is well softened; neutralize with
concentrated hydrochloric acid, using litmus as an indicator ami add 10 cc. more
of concentrated hydrochloric acid. Add a pinch of sand to prevent bumping and
boil gently for 5 minutes, keeping the heaker covered with a watch glass. Cool
the solution, transfer to a Rohrig tube or some similar apparatus, rinse the beaker
with 25 cc. of washed ethyl ether and shake well. Add 25 cc. of redistilled petro-
leum ether (b. p. below G5°C), let the solutions separate and proceed from this
point as directed in 12.

298 METHODS OF AXALYSIS

62 Babcock Method. — Tentative.

Weigh about 6 grams of the cheese in a tared dish. Add 10 cc. of boiling water and
stir with a rod until the cheese softens and an even emulsion is formed, preferably
adding a few drops of strong ammonium hydroxid, and keep the beaker in hot water
until the emulsion is nearly completed and the mass free from lumps. If the sample
is a whole milk cheese, employ a Babcock cream bottle. After cooling, transfer the
contents of the beaker to the test bottle by adding to the beaker about half of the
17.6 cc. of sulphuric acid usually employed in this test, stirring with a rod, and
pouring carefully into the bottle, using the remainder of the acid in 2 portions for
washing out the beaker. Then proceed as directed in 15. Multiply the fat reading
by 18 and divide by the weight of the sample taken to obtain the per cent of fat.

BIBLIOGRAPHY.

1 Browne. Handbook of Sugar Analysis. 1912, p. 252.

2 Z. Nahr. Genussm., 1905, 9: 531.

3 Farrington and Woll. Testing Milk and Its Products. 23rd ed., 1916.

4 Van Slvke. Modern Methods of Testing Milk and Milk Products. Rev. ed..
1907.

5Chem. Ztg., 1908, 32:617.

XXIII. FATS AND OILS.

1 PREPARATION OF SAMPLE.— OFFICIAL.

Melt solid fats and filter by means of a hot water funnel or similar apparatus.

Make the different determinations on samples of this melted, homogeneous mass.

Filter oils that are not clear. Keep oils and fats in a cool place and protected from

light and air, otherwise they will soon become rancid. Weigh out at one time as

many portions as are needed for the various determinations, using a small beaker

or weighing burette.

SPECIFIC GRAVITY.

20°C

9 At '■ — Tentative.

4°

20 °C

Determine the specific gravity of the oil at -pr1 by means of a pycnometer.

If the specific gravity of the oil is determined at other than standard tempera-
ture, the approximate specific gravity at 20°C. may be calculated by means of the
following formula:

G = G' + 0.0007 (T-20°C.) in which

G = specific gravity at 20°C. ;

T°C
G' = specific gravity at -p-' ;

T = temperature at which the specific gravity was determined;
0.0007 = mean correction1 for 1°C.

At the Temperature of Boiling Water.— Official.

3 STANDARDIZATION OF FLASKS.

(a) Fill a tared, 25-30 cc. specific gravity flask with freshly boiled, hot water.
Place in a briskly boiling water bath for 30 minutes, replacing any evaporation
from the flask by the addition of boiling water. Then insert the stopper, previous-
ly heated to 100°C., remove the flask, cool and weigh.

(b) The following formula may be used for calculating the weight of water (\VT)
which a given flask will hold at T° (weighed in air with brass weights at the tempera-
ture of the room) from the weight of water (W*) (weighed in air with brass weights
at the temperature of the room) contained therein at t°:

dT
WT = W* -r [1 + 0.000026 (T - t)] in which
dr

(F = the density of water at T°;

d1 = the density of water at t°.

4 DETERMINATION.

Fill the flask, dried at the temperature of boiling water, with the dry. hot, freshly-
filtered fat, which should be entirely free from air bubbles; keep in the water bath
30 minutes at the temperature of boiling water. Insert the stopper, previously
heated to 100°C., cool and weigh. Divide the weight of contained fat by the weight
of contained water previously found to obtain the specific gravity.

The weight of water at boiling temperature must be determined under the baro-
metric conditions prevailing at the time the determination is >

299

300 METHODS OF ANALYSIS [Chap.

INDEX OF REFRACTION.
K General Directions.— Tentative.

Place the instrument in such a position that diffuse daylight or any form of arti-
ficial light can readily be obtained for illumination. Circulate through the prisms
a stream of water of constant temperature.

Determine the index of refraction with any standard instrument, reading oils at
20°C. and fats at 40°C.

The readings of the Zeiss butyro-refractometer can be reduced to standard tem-
perature by the following formula2:

R = R' + 0.55 (T' - T) in which
R = the reading reduced to temperature T;
R' = the reading at T'C.

T' = the temperature at which reading R' is made;
T = the standard temperature;
0.55 = correction in scale divisions for 1°C.
With oils the factor 0.58 is substituted in the formula for 0.55, since they have a
higher index of refraction.

The readings of instruments, which give the index of refraction directly, can be
reduced to standard temperature by substituting the factor 0.000365 for 0.55 in the
formula. As the temperature rises the refractive index falls.

The instrument used may be standardized with water at 20°C, the theoretical
refractive index of water at that temperature being 1.3330. Any correction found
should be made on all readings.

The index of refraction varies directly with the specific gravity. If the results
appear abnormal, compare the specific refractive power3 with the normal. Calcu-

N - 1
late the specific refractive power from the formula — — , in which N equals

the refractive index and D the specific gravity. According to Procter* the Lorenz

N2-l . , , , N — 1

formula gives much more satisfactory results than — — — .

(N2 + 2) D D

§ By Means of the Abbe Refractometer.— Official.

To charge the instrument, open the double prism by means of the screw head
and place a few drops of the sample on the prism or, if preferred, open the prisms
slightly by turning the screw head and pour a few drops of the sample into the
funnel-shaped aperture between the prisms. Then close the prisms firmly by
tightening the screw head. Allow the instrument to stand for a few minutes
before the reading is made, so that the temperature of the sample and the instru-
ment will be the same.

The method of measurement is based upon the observation of the position of the
border line of total reflection in relation to the faces of a prism of flint glass. Bring
this border line into the field of vision of the telescope by rotating the double prism
by means of the alidade in the following manner: Hold the sector firmly, move the
alidade backward or forward until the field of vision is divided into a light and a
dark portion. The line dividing these portions is the "border line". This, as a
rule, will not be a sharp line but a band of color which is eliminated by
rotating the screw head of the compensator until a sharp, colorless line is obtained.
The border line should now be adjusted so that it falls on the point of intersection
of the 2 cross hairs. Read the refractive index of the substance directly on the
scale of the sector. Check the correctness of the instrument, as directed under 5,
or by means of the quartz plate which accompanies it, using monobromnaphtha-
lene, and make the necessary correction in the reading.

xxni]

FATS AND OILS

301

7 By Means of the Zeiss Butyro-Refractometer. — Official.

Place 2 or 3 drops of the filtered fat on the surface of the lower prism. Close the
prisms and adjust the mirror until it gives the sharpest reading. If the reading
be indistinct after running water of a constant temperature through the instru-
ment for some time, the fat is unevenly distributed on the surfaces of the prism.
As the index of refraction is greatly affected by temperature, care must be used to
keep the latter constant. The instrument should be carefully adjusted by means of
the standard fluid which is supplied with it. Convert the degrees of the instru-
ment into refractive indices from 8.

8

Table 20.
Butyro-refractometer readings and indices of refraction.

READING

INDEX OF
REFRACTION

READING

INDEX OF
REFRACTION

READING

INDEX OF

REFRACTION

READING

INDEX OF
REFRACTION

40.0

1.4524

50.0

1.4593

60.0

1.4659

70.0

1.4723

40.5

1.4527

50.5

1.4596

60.5

1.4662

70.5

1.4726

41.0

1.4531

51.0

1.4600

61.0

1.4665

71.0

1.4729

41.5

1.4534

51.5

1.4603

61.5

1.4668

71.5

1.4732

42.0

1.4538

52.0

1.4607

62.0

1.4672

72.0

1.4735

42.5

1.4541

52.5

1.4610

62.5

1.4675

72.5

1.4738

43.0

1.4545

53.0

1.4613

63.0

1.4678

73.0

1.4741

43.5

1.4548

53.5

1.4616

63.5

1.4681

73.5

1.4744

44.0

1.4552

54.0

1.4619

64.0

1.4685

74.0

1.4747

44.5

1.4555

54.5

1.4623

64.5

1.4688

74.5

1.4750

45.0

1.4558

55.0

1.4626

65.0

1.4691

75.0

1.4753

45.5

1.4562

55.5

1.4629

65.5

1.4694

75.5

1.4756

46.0

1.4565

56.0

1.4633

66.0

1.4697

76.0

1.4759

46.5

1.4569

56.5

1.4636

66.5

1.4700

76.5

1.4762

47.0

1.4572

57.0

1.4639

67.0

1.4704

77.0

1.4765

47.5

1.4576

57.5

1.4642

67.5

1.4707

77.5

1.4768

48.0

1.4579

58.0

1.4646

68.0

1.4710

78.0

1.4771

48.5

1.4583

58.5

1.4649

68.5

1.4713

78.5

1.4774

49.0

1.4586

59.0

1.4652

69.0

1.4717

79.0

1.4777

49.5

1.4590

59.5

1.4656

69.5

1.4720

79.5

1.4780

MELTING POINT OF FATS AND FATTY ACIDS.

Wiley Method. — Official.

9 REAGENT.

Alcohol-water mixture. — Specific gravity same as that of the fat to be examined.
Prepare by boiling, separately, water and 95% alcohol by volume for 10 minutes
to remove the gases which may be held in solution. While still hot pour the water
into the test tube until it is almost half full. Nearly fill the test tube with the hot
alcohol, poured down the side of the inclined tube to avoid too much mixing. If
the alcohol be added after the water has cooled, the mixture will contain so many
air bubbles as to be unfit for use.

10

DETERMINATION.

Prepare disks of fat as follows: Allow the melted and filtered fal Ui fall a distance
of 15-20 cm. from a dropping tube upon a piece of ice or upon the surface of cold
mercury. The disks thus formed should be 1-1.5 cm. in diameter and weigh about

302 METHODS OF ANALYSIS [Chap.

200 mg. When solid remove the disk and allow to stand 2-3 hours in order to obtain
the normal melting point.

Place a test tube, 30 by 3.5 cm., containing the alcohol-water mixture, in a tall
beaker, 35 by 10 cm., containing ice and water, until cold. Then drop the disk of
fat into the tube and it will at once sink to a point where the density of the alcohol-
water mixture is exactly equivalent to its own. Lower an accurate thermometer,
which can be read to 0.1°C, into the test tube until the bulb is just above the disk.
In order to secure an even temperature in all parts of the alcohol-water mixture
around the disk, stir gently with the thermometer. Slowly heat the water in the
beaker, constantly stirring it by means of an air blast or other suitable device.

When the temperature of the alcohol-water mixture rises to about 6°C. below
the melting point of the fat, the disk of fat begins to shrivel and gradually rolls up
into an irregular mass. Lower the thermometer until the fat particle is even with
the center of the bulb. Rotate the thermometer bulb gently and regulate the
temperature so that about 10 minutes for the increment of the last 2°C. are
required. As soon as the fat mass becomes spherical, read the thermometer.
Remove the tube from the bath and again cool. Place in the bath a second tube
containing the alcohol-water mixture. The test tube is of sufficiently low tempera-
ture to cool the bath to the desired point, ice water having been used for cooling.
After the first or preliminary determination, regulate the temperature of the bath
so as to reach a maximum of about 1.5°C. above the melting point of the fat under
examination.

Do not allow the edge of the disk to touch the sides of the tube. If so, make a
new determination. Run triplicate determinations of which the second and third
results should agree closely.

1 1 Capillary Tube Method'. — Tentative.

Draw the melted fat or fatty acids into a thin-walled capillary tube. Use a
column of fat 1-2 cm. long, according to the length of the thermometer bulb. Seal
1 end of the tube and cool on ice 12-15 hours. Attach the capillary tube to the bulb
of an accurate thermometer, graduated to 0.2°C, immerse in a large test tube of
water surrounded by a beaker of water and heat very slowly. An apparatus
similar to that indicated in Fig. 12 may be used. The temperature at which the
substance becomes transparent is taken as the melting point.

TITER TEST.
Alcoholic or Aqueous Sodium Hydroxid Method. — Tentative.

1 2 APPARATUS.

Standard thermometer. — The thermometer must have a zero mark, 0.1° gradua-
tions between 10°-60°C., and auxiliary reservoirs at the upper end and between the
0° and the 10° marl. s. The cavity in the capillary tube between the 0° and the
10° marks must be at least 1 cm. below the 10° mark, which must be about 3-4 cm.
above the bulb, the total length of the thermometer being about 38 cm. The bulb
should be about 3 cm. long and 6 mm. in diameter. The stem of the thermometer
should be 6 mm. in diameter and made of the best thermometer tubing, with scale
etched on the stem, the graduation to be clear cut and distinct. The thermometer
should have been annealed for 75 hours at 450°C, and the bulb should be of Jena
normal 16m glass, moderately thin, so that the thermometer will be quick-acting.

XXIII]

FATS AND OILS

303

13

DETERMINATION.

Saponify 75 grams of the sample in a metal dish with 60 cc. of 30% sodium hy-
droxid solution (36° Baume) and 75 cc. of 95% alcohol by volume or 120 cc. of
water. Evaporate to dryness over a very low flame or on an iron or asbestos plate,
stirring constantly. Dissolve the dry soap in a .liter of boiling water and, if alcohol
has been used, boil for 40 minutes to remove it, adding sufficient water to replace
that lost in boiling. Liberate the fatty acids by adding 100 cc. of 30% sulphuric

FIG. 12. APPARATUS FOR THE MELTING POINT DETERMINATION.

acid (25° Baume) and boil until they form a clear, transparent layer. Wash with
boiling water until free from sulphuric acid, collect in a small beaker and
place on a steam bath until the water has settled and the fatty acids are clear; then
decant into a dry beaker, filter while hot and dry 20 minutes at 100°C. When
dried, cool the fatty acids to 15°-20°C. above I he expected titer and t ransfer to the
titer tube, 25 by 100 mm. (1 by 4 inches) and made of filass aboul 1 mm. in thickness.
Place in a 16 ounce wide-mouthed bottle of clear glass, 70 by 150 mm. (2.8 by 6

304 METHODS OF ANALYSIS [Chap.

inches), fitted with a perforated cork, so as to hold the tube rigidly when in position.
Suspend the standard thermometer so that it can be used as a stirrer, and stir the
mass slowly until the mercury remains stationary for 30 seconds. Then allow the
thermometer to hang quietly, with the bulb in the center of the mass, and observe
the rise of the mercury column. The highest point to which it rises is regarded
as the titer of the fatty acids.

Test the fatty acids for complete saponification as follows:

Place 3 cc. in a test tube and add 15 cc. of 95% alcohol by volume. Bring the
mixture to a boil and add an equal volume of ammonium hydroxid (sp. gr. 0.96).
A clear solution should result. The titer must be made at about 20°C. for all fata
having a titer above 30°C, and at 10°C. below the titer for all other fats.

14 Glycerol-Potassium Hydroxid Method. — Tentative.

Heat 75 cc. of glycerol-potassium hydroxid solution (25 grams of potassium hy-
droxid in 100 cc. of high-test glycerol) to 150°C. in an 800 cc. beaker; then add 50 cc.
of the oil or melted fat, previously filtered if necessary to remove foreign substances.
Saponification often takes place almost immediately, but heating, with frequent
stirring, should be continued for 15 minutes, avoiding a temperature much above
150°C. When the saponification is complete, as indicated by the perfectly homo-
geneous solution, pour the soap into an 800 cc. casserole containing about 500 cc.
of nearly boiling water, add carefully 50 cc. of 30% sulphuric acid and heat the
solution, with frequent stirring, until the layer of fatty acids separates out perfectly
clear. Transfer the fatty acids to a tall separatory funnel, wash 3-4 times with
boiling water to remove all mineral acids, draw the fatty acids off into a small
beaker, and allow to stand on a steam bath until the water has settled out and the
acids are clear. Filter into a dry beaker and heat to 150°C. on a thin asbestos plate,
stirring continually with the thermometer, transfer to a titer tube, fill it to within
2.5 cm. of the top and take the titer as directed in 13.

IODIN ABSORPTION NUMBER.
Hubl Method— Official.

1 5 BEAGENTS.

(a) Hiibl's iodin solution. — Dissolve 26 grams of pure iodin in 500 cc. of 95% alco-
hol by volume. Dissolve 30 grams of mercuric chlorid in 500 cc. of 95% alcohol
by volume. Filter the latter solution, if necessary, and mix the 2 solutions. Let
the mixed solution stand 12 hours before using. The solution loses strength with
age, but can be used so long as 35 cc. of N/10 thiosulphate are equivalent to 25 cc.
of the iodin solution.

(b) N/10 sodium thiosulphate. — Standardize this solution as follows: Place in a
glass-stoppered flask 20 cc. of the N/10 potassium dichromate and 10 cc. of the 15%
potassium iodid solution. Add 5 cc. of strong hydrochloric acid. Dilute with 100
cc. of water and allow the N/10 sodium thiosulphate to flow slowly into the flask
until the yellow color of the liquid has almost disappeared, add a few drops of the
starch indicator and, with constant shaking, continue to add the N/10 sodium thio-
sulphate until the blue color just disappears.

(C) Starch indicator. — Prepare as directed under VII, 3 (a).

(d) 15% potassium iodid solution.

(e) N/10 potassium dichromate. — The dichromate solution should be checked
against pure iron.

XXIII] FATS AND OILS 305

1 6 DETERMINATION.

Weigh about 0.500 gram of fat, or 0.250 gram of oil (0.100-0.200 gram in the case
of drying oils which have a very high absorbent power), into a 500 cc. glass-stoppered
flask or bottle. Dissolve the fat or oil in 10 cc. of chloroform. Acid 30 cc. of the
Hiibl iodin solution in the case of fats, or 40-50 cc. in the case of oils. Place the
bottle in a dark place and allow to stand for 3 hours, shaking occasionally.

This time must be adhered to closely in order to obtain good results. The time
allowed does not give the complete iodin absorption power of an oil or fat and can
not be compared with determinations in which 6-12 hours have been used. It gives
very satisfactory comparative results, but the time factor must be closely observed.

The excess of iodin should be at least as much as is absorbed. Add 20 cc. of the
15% potassium iodid solution, shake thoroughly and then add 100 cc. of water, wash-
ing down any free iodin that may be found on the stopper. Titrate the iodin with
the N/10 sodium thiosulphate, adding the latter gradually, with constant shaking,
until the yellow color of the solution has almost disappeared. Add a few drops of
the starch indicator and continue the titration until the blue color has entirely
disappeared. Toward the end of the titration, stopper the bottle and shake vio-
lently, so that any iodin remaining in solution in the chloroform may be taken up
by the potassium iodid solution. Conduct 2 blank determinations along with that
on the sample. The number of cc. of the N/10 sodium thiosulphate required by the
blank less the amount used in the determination gives the thiosulphate equivalent
of the iodin absorbed by the fat or oil. Ascertain the iodin number by calculating
the per cent by weight of iodin absorbed.

Hanus Method. — Official.

1 7 REAGENTS.

Hanus' iodin solution. — Dissolve 13.2 grams of iodin in 1 liter of glacial acetic
acid (99.5%) which shows no reduction with dichromate and sulphuric acid. Add
enough bromin to double the halogen content as determined by titration (3 cc. of
bromin are about the proper amount). The iodin may be dissolved by heating
but the solution should be cold when the bromin is added.

A convenient way to prepare the Hanus solution is as follows: Measure 825 cc.
of acetic acid which has shown no reduction by the dichromate test and dissolve in
it 13.615 grams of iodin with the aid of heat. Cool and titrate 25 cc. of this solu-
tion against the N/10 sodium thiosulphate. Add 3 cc. of bromin to 200 cc. of acetic
acid and titrate 5 cc. of the solution against the N/10 sodium thiosulphate. Cal-
culate the quantity of bromin solution required exactly to double the halogen con-
tent of the remaining 800 cc. of iodin solution as follows:

A = p; in which

A = cc. of bromin solution required;

B = S00 X the thiosulphate equivalent of 1 cc. of iodin solution;

C = the thiosulphate equivalent of 1 cc. of bromin solution.
Example: 136.15 grams of iodin are dissolved in 8250 cc. of acetic acid. 30 cc.
of bromin are dissolved in 2000 cc. of acetic acid. Titrating 50 cc. of the iodin
solution against the standard thiosulphate shows that 1 cc. of the iodin solution
equals 1.1 cc. of the thiosulphate (0. 0165 gram of iodin). Titrating ■"> cc. of the bro-
min solution shows that 1 cc. of the bromin solution equals 4.6 cc. of the t biosulphate,
Then the quantity of bromin solution required to double the halogen content of

8°00 X 1 1
the remaining 8200 cc. of iodin solution is equivalent to j a~~~ or ^61 cc^ ^TPon

306 METHODS OF ANALYSIS [Chap.

mixing the 2 solutions in this proportion, a total volume of 10161 cc. is obtained,

containing 135.3 grams of iodin. In order to reduce this solution to the proper

strength (13.2 grams iodin per liter), 10.161 X 13.2= 134.1; 135.3- 134.1 = 1.2 grams

c j- *■■ 1-2X 1000 M , .. - , , . , ,

of iodin present in excess, or -r-^ — = 91 cc. of acetic acid which must be added.

The other reagents used are described under 15.

18 DETERMINATION.

Weigh about 0.500 gram of fat, or 0.250 gram of oil (0.100-0.200 gram in the case
of drying oils which have a very high absorbent power), into a 500 cc. glass-stoppered
flask or bottle. Dissolve the fat, or oil, in 10 cc. of chloroform, add 25 cc. of the
Hanus iodin solution and allow to stand for 30 minutes, shaking occasionally.
The excess of iodin should be at least 60% of the amount added. Add 10 cc. of the
15% potassium iodid solution and continue as directed under 16.

SAPONIFICATION NUMBER (KOETTSTORFER NUMBER).— OFFICIAL.

19 REAGENTS.

(a) N/2 hydrochloric acid. — Prepare as directed under I, 16 (a).

(b) Alcoholic potassium hydroxid solution. — Dissolve 40 grams of the purest
potassium hydroxid in 1 liter of 95% redistilled alcohol by volume. The alcohol
should be redistilled from potassium hydroxid over which it has been standing for
some time, or with which it has been boiled for some time using a reflux condenser.
The solution must be clear and the potassium hydroxid free from carbonates.

20 DETERMINATION.

Weigh accurately about 5 grams of the filtered sample into a 250-300 cc. Erlen-
meyer flask. Pipette 50 cc. of the alcoholic potassium hydroxid solution into the
flask, allowing the pipette to drain for a definite time. Connect the flask with an
air condenser and boil until the fat is completely saponified (about 30 minutes).
Cool and titrate with the N/2 hydrochloric acid, using phenolphthalein as an indi-
cator. Calculate the Koettstorfer number (mg. of potassium hydroxid required to
saponify 1 gram of fat). Conduct 2 or 3 blank determinations, using the same
pipette and draining for the same length of time as above.

21 SOLUBLE ACIDS.-OFFICIAL.

Place the flask, used in 20, on a water bath and evaporate the alcohol. Add such
an amount of N/2 hydrochloric acid that its volume plus the amount used in titrat-
ing for the saponification number will be 1 cc. in excess of the amount required to
neutralize the 50 cc. of the alcoholic potassium hydroxid solution added, and place
on the steam bath until the separated fatty acids form a clear layer on the upper
surface of the liquid. Fill to the neck with hot water and cool in ice water until
the cake of fatty acids is thoroughly hardened. Pour the liquid contents of the
flask through a filter into a liter flask. Fill the flask again with hot water, set on
the steam bath until the fatty acids collect at the surface, cool by immersing in ice
water, and again filter the liquid into the liter flask. Repeat this treatment with
hot water 3 times, cooling and collecting the washings in the liter flask after each
treatment. Titrate the combined washings with N/10 alkali, using phenolphthalein
as an indicator. Subtract 5 (corresponding to the excess of 1 cc. of N/2 acid) from
the number of cc. of N/10 alkali used and multiply by 0.00SS to obtain the weight
of soluble acids as butyric acid. Calculate the percentage of soluble acids.

XXIII] FATS AND OILS 307

22 INSOLUBLE ACIDS (HEHNER NUMBER).— OFFICIAL.

Allow the flask, containing the cake of insoluble fatty acids from 21 and the
paper through which the soluble fatty acids have been filtered, to drain and dry
for 12 hours. Transfer the cake, together with as much of the fatty acids as can
be removed from the filter paper, to a weighed, wide-mouthed beaker flask. Then
place the funnel, containing the filter, in the neck of the flask and wash the paper
thoroughly with hot absolute alcohol. Remove the funnel, evaporate off the alco-
hol, dry for 2 hours at 100°C, cool in a desiccator and weigh. Again dry for 2 hours,
cool and weigh. If there is any considerable decrease in weight, re-heat for 2 hours
and weigh again. Calculate the percentage of insoluble fatty acids.

SOLUBLE VOLATILE ACIDS (REICHERT-MEISSL NUMBER).

(As these determinations are entirely empirical, the directions given must be
followed exactly. In reporting results the method used should always be stated.)

Reichert-Meissl Method. — Official.

23 REAGENTS.

(a) Sodium hydroxid solution (1 to 1). — The sodium hydroxid should be as free as
possible from carbonates. Protect the solution from contact with carbon dioxid.
Allow to settle and use only the clear liquid.

(b) Potassium hydroxid solution. — Dissolve 100 grams of the purest potassium
hydroxid in 58 cc. of hot water. Cool in a stoppered vessel, decant the clear solu-
tion and protect from contact with carbon dioxid.

(C) 95% alcohol by volume. — Distilled over sodium hydroxid.

(d) Dilute sulphuric acid. — Dilute 200 cc. of the strongest acid to 1 liter with
water.

(e) Barium (or sodium) hydroxid solution. — Standardize an approximately N/10
solution.

(f ) Indicator. — Dissolve 1 gram of phenolphthalein in 100 cc. of 95% alcohol.

(£) Pumice stone. — Heat small pieces to a white heat, plunge in water, and keep
under water until used.

24

SAPONIFICATION.

Weigh 5.75 cc, about 5 grams, of the filtered sample, into a saponification flask
and proceed by 1 of the following 3 methods.

(1) Under pressure with alcohol. — Place 10 cc. of the 95% alcohol in the flask
containing the fat (the flask must be made of strong, well-annealed glass, capable
of resisting the tension of alcoholic vapor at 100°C.) and add 2 cc. of the sodium
hydroxid solution. Insert a soft, cork stopper into the neck of the flask, tie down
and place the stoppered flask on a water or steam bath for at Least an hour,
rotating the flask gently from time to time. Cool before opening.

(2) Under pressure without the use of alcohol. — Place 2 cc. of the potassium hy-
droxid solution in the flask containing the fat (the flask being round-bottomed and
made of well-annealed glass to resist pressure), cork and heat as directed under
(1). This method avoids the formation of esters and the removal of the alcohol
after saponification.

(3) With a reflux condenser and the use of alcohol. — Place 10 cc. of the 95% alcohol
in the flask containing the fat, add 2 c,c. of the sodium hydroxid solution and heat on
a steam bath until the saponification is complete, using a reflux condenser.

After the saponification, if alcohol was used, remove it by evaporation on a
steam bath.

308 METHODS OF ANALYSIS [Chap.

25 DISTILLATION AND TITRATION.

Dissolve the soap, obtained as directed under 24, by adding 135 cc. of recently
boiled water (132 cc. if potassium hydroxid was used in the saponification) and warm
on the water bath, with occasional shaking, until the solution is clear. Cool to
60°-70°C., add 5 cc. of the dilute sulphuric acid (8 cc. if potassium hydroxid was
used in the saponification), stopper loosely and heat on the water bath until the
fatty acids form a clear, transparent layer. Cool to room temperature, add a few
pieces of the pumice stone and connect with a glass condenser by means of a bulb
tube. Heat slowly with a free flame until ebullition begins and distil, regulating
the flame so as to collect 110 cc. of distillate in as nearly 30 minutes as possible.
Mix this distillate, filter through a dry filter, and titrate 100 cc. with the standard
barium or sodium hydroxid solution, using phenolphthalein as an indicator. The
red color should remain unchanged for 2-3 minutes.

Multiply the number of cc. of N/10 alkali used by 1.1, divide by the weight
of fat taken and multiply by 5 to obtain the Reichert-Meissl number. Correct the
result by the figure obtained in a blank determination.

Leffman and Beam Method. — Official.

26 KE AGENTS.

Glycerol-soda solution. — Add 20 cc. of the sodium hydroxid solution, prepared as
directed under 23 (a), to 180 cc. of pure, concentrated glycerol.
The other reagents used are described under 23.

27

DETERMINATION.

Add 20 cc. of the glycerol-soda solution to about 5 grams of the fat in a flask,
weighed as directed under 24, and heat over a free flame, or on an asbestos plate,
until complete saponification takes place, as shown by the mixture becoming
perfectly clear. If foaming occurs, shake the flask gently.

Add 135 cc. of recently boiled water, drop by drop at first, to prevent foaming,
and 5 cc. of the dilute sulphuric acid, distil without previous melting of the fatty
acids, using an apparatus similar to that illustrated in 28, Fig. 13, regulating the
flame so as to collect 110 cc. of distillate in as nearly 30 minutes as possible. Filter,
titrate the volatile acids and calculate the Reichert-Meissl number, as directed
under 25. Conduct a blank determination and correct the result accordingly.

INSOLUBLE VOLATILE ACIDS (POLENSKE NUMBER).

28 Polenske Method*. — Tentative.

Proceed as directed under 27 up to the point at which 110 cc. of distillate have
been collected, except that only 20 minutes are allowed for the distillation, em-
ploying an apparatus of the exact dimensions illustrated in Fig. 13. Substitute a
25 cc. cylinder for the receiving flask to collect any drops that may fall after the
flame has been removed. Immerse the flask containing the distillate almost com-
pletely in water at 15°C. for 15 minutes, filter the 110 cc. of distillate and determine
the approximate Reichert-Meissl number, if desired, as in 27, avoiding too violent
shaking of the distillate and consequent emulsification of the insoluble acids pre-
vious to filtration. Remove the remainder of the soluble acids from the insoluble
acids upon the filter paper by washing with 3 successive portions of 15 cc. of water,
previously passed through the condenser, the 25 cc. cylinder and the 110 cc. receiv-
ing flask. Then dissolve the insoluble acids by passing 3 successive 15 cc. por-

xxini

FATS AND OILS

309

tions of neutral 90% alcohol by volume through the filter, each portion previously-
passed through the condenser, the 25 cc. cylinder and the 110 cc. receiving flask.
Titrate the combined alcoholic washings with N/10 sodium hydroxid, using phenol-
phthalein as an indicator.

Run a blank in the same manner and subtract the quantity of the standard alkali
required to neutralize the 45 cc. of alcohol, used in washing the apparatus and filter
paper of the blank, from that required in each Polenske determination. Report
the Polenske number as the number of cc. of N/10 alkali required to neutralize the
insoluble volatile acids from the 110 cc. of distillate as obtained above. Since the
entire distillate is filtered it is not necessary to multiply the burette reading by 1.1,
as in 25, but a calculation must be made, as directed in 25, to reduce the actual
number of cc. found in the titration to the number which would have been required
had exactly 5 grams of fat been used.

FIG. 13. APPARATUS7 FOR THE DETERMINATION OF THE POLENSKE NUMBER.

29

LIQUID AND SOLID FATTY ACIDS.
Muter Method, Modified by Lane*. — Tentative.

Weigh 5 grams of the oil or fat into an Erlenmeyer flask, saponify, precipitate with
lead acetate solution and treat the precipitated lead soap with ether, as directed
under 37. Filter the ether solution of the soluble lead soap into a Muter tube or
separatory funnel and decompose the soap by shaking with -10 cc. of hydrochloric
acid (1 to 5). The soap is completely decomposed when the ether becomes clear
and colorless.

Draw off the lead chlorid from the ether solution and wash the ether free from
acid. Evaporate, until free from ether, an aliquot of this solution in an atmosphere
of carbon dioxid, in order to prevent (he oxidation of the oleic acid, and weigh to
determine the per cent of liquid acids; determine the iodin number as directed in
16 or 18, using 0.2-0.3 gram of this residue.

310 METHODS OF ANALYSIS [Chap.

As it is very difficult to dry the unsaturated acids without very serious oxidation,
it is just as satisfactory to determine the weight of insoluble acids by the following
method:

Wash the insoluble soap left on the filter into a flask, decompose with hydro-
chloric acid and heat until the fatty acids are melted. Fill the flask with hot water,
cool, pour off the water and again wash the solidified fatty acids. Dissolve in hot
95% alcohol by volume, transfer to a weighed dish, remove the alcohol by evapo-
ration, dry, weigh and calculate the percent of solid fatty acids.

30 FREE FATTY ACIDS.-OFFICIAL.

Weigh 20 grams of fat, or oil, into a flask, add 50 cc. of 95% alcohol by volume
which has been neutralized with dilute sodium hydroxid solution, using phenol-
phthalein as an indicator, and heat to boiling. Shake the flask thoroughly in order
to dissolve the free fatty acids as completely as possible. Titrate with N/10 alkali,
shaking thoroughly until the pink color persists after vigorous shaking.

Express the results either as percentage of oleic acid, as acid degree (cc. of N 1
alkali required to neutralize the free acids in 100 grams of oil or fat), or as acid
value (mg. of potassium hydroxid required to saturate the free acids in 1 gram of fat
or oil).

One cc. of N/10 alkali is equivalent to 0.0282 gram of oleic acid.

ACETYL VALUE.

31 Benedikt-Lewkoicitsch Method*. — Tentative.

Boil the oil or fat with an equal volume of acetic anhydrid for 2 hours, pour the
mixture into a large beaker containing 500 cc. of water and boil for 30 minutes.
To prevent bumping, pass a slow current of carbon dioxid into the liquid through a
finely drawn out tube reaching nearly to the bottom. Allow the mixture to sepa-
rate into 2 layers, siphon off the water, and boil the oily layer with fresh water
until it is no longer acid to litmus paper. Separate the acetylated fat from the water
and dry and filter in a drying oven.

Weigh 2-4 grams of the acetylated fats into a flask and saponify with alcoholic
potash as in 20. If the distillation process is to be adopted, it is not necessary to
work with a standardized alcoholic potassium hydroxid solution, but in the fil-
tration method, which is much shorter, the alcoholic potassium hydroxid solution
must be measured exactly. In either case evaporate the alcohol after saponification
and dissolve the soap in water. Then either distil or filter as follows:

(1) Distillation. — Acidify with sulphuric acid (1 to 10) and distil as in 25. As
several hundred cc. must be distilled, either run a current of steam through or add
portions of water from time to time (500-700 cc. of distillate will be sufficient).
Filter the distillates to remove any insoluble acids carried over by the steam and
titrate with N/10 potassium hydroxid, using phenolphthalein as an indicator. Mul-
tiply the number of cc. of alkali employed by 5.61 and divide by the weight of sub-
stance used to obtain the acetyl value.

(2) Filtration. — Add to the soap solution a quantity of standard sulphuric acid
exactly corresponding to the amount of alcoholic potassium hydroxid solution
added, warm gently, filter off the free fatty acids which collect on top, wash with
boiling water until the washings are no longer acid and titrate the filtrate with N 10
potassium hydroxid, using phenolphthalein as an indicator. Calculate the acetyl
value as directed under (1).

XXIII] FATS AND OILS 311

CHOLESTEROL AND PHYTOSTEROL IN MIXTURES OF ANIMAL AND VEGETABLE FATS.
32 Alcohol Extract-ion Method10. — Tentative.

Introduce 200-300 grams of the melted fat into a fiat-bottomed liter flask. Close
the neck of the flask with a 3-holed stopper and insert through these holes: (1) a
reflux condenser; (2) a right-angled glass tube, one arm of which reaches to a point
6 mm. above the surface of the melted fat, the other being closed a short distance
from the flask by means of a short piece of rubber tubing and a pinch-cock; (3) a
glass tube bent so that one arm reaches down to the bottom of the flask and the
other serves as a delivery tube for a 700 cc. round-bottomed flask containing 500 cc.
of 95% alcohol by volume.

Place the flasks, containing the melted fat and the alcohol, on a steam bath and
heat so that the alcohol vapor passes through the melted fat in the liter flask and
is condensed in the reflux condenser, finally collecting in a layer over the melted
fat. After all the alcohol has passed in this manner into the flask containing the
fat, disconnect the flask from which the alcohol has been distilled and attach a
tube to the short piece of rubber tubing attached to the right-angled glass tube
[see (2) above] and siphon the alcohol layer back into the alcohol distillation flask.
Reconnect as at first and again distil the alcohol as in the first operation. When
all the alcohol has been distilled, siphon it again into the distillation flask and
extract in the same manner for a third time.

Discard the fat and retain the alcohol which now contains practically all of the
cholesterol and phytosterol originally present in the fat. Concentrate the alcoholic
solution to about 250 cc. and add 20 cc. of potassium hydroxid solution (1 to 1)
to the boiling liquid. Boil for 10 minute* to insure complete saponification of the
fat, cool to room temperature and pour into a large separatory funnel containing
500 cc. of warm ether. Shake to insure thorough mixing and add 500 cc. of water.
Rotate the funnel gently to avoid the formation of extremely stubborn emulsions,
but mix the water thoroughly with the alcohol-ether-soap solution. A clear, sharp
separation takes place at once. Draw off the soap solution and wash the ether layer
with 300 cc. of water, avoiding shaking. Repeat the washing of the ether solution
with small quantities of water until all the soap is removed. Transfer the ether
layer to a flask and distil the ether until the volume of liquid remaining in the
flask measures about 25 cc. Transfer this residue to a tall 50 cc. beaker and
continue the evaporation until all the ether is driven off and the residue is per-
fectly dry. If desired, a tared beaker may be used and the weight of the unsaponi-
fiable matter determined at this point.

Add 3-5 cc. of acetic anhydrid to the residue in the beaker, cover the beaker
with a watch glass and heat to boiling over a free flame. After boiling for a few
seconds, remove the beaker from the flame, cool and add 35 cc. of 60% alcohol by
volume. Mix the contents of the beaker thoroughly, filter off the alcoholic solution
and wash the precipitate with 00% alcohol. Dissolve the precipitate on the filter
with a stream of hot 80% alcohol by volume and wash the insoluble portion well
with 80% alcohol. Acetates of cholesterol and phytosterol arc dissolved while the
greater portion of .the impurities present (including paraffin and paraffin oil if pres-
ent) remain behind on the filter. Cool the combined filtrate and washings to a
temperature of 10°-12°C. and allow to stand at that temperature for 2-3 hours.
During this time the acetates of cholesterol and phytosterol crystallize from the
solution. Collect the crystals upon a fill it, wash with cold 80( , alcohol and then
dissolve them in a minimum amount of hoi absolute alcohol. Collect the alcoholic
solution of the acetates in a small, glass evaporating dish, add 2 or 3 drops of water
to the solution and heat if not perfectly clear. Allow the alcohol to evaporate

312 METHODS OF ANALYSIS [Chap.

spontaneously, the contents of the dish being stirred occasionally to mix the deposit
of crystals, which form upon the edges, with the main body of the liquid. As soon
as a good deposit of crystals has formed, collect them upon a hardened filter, wash
twice with cold 90% alcohol and dry by suction, drying finally at 100°C. for 30 min-
utes, and determine the melting point in the apparatus shown in 1 1 , Fig. 12, using
sulphuric acid in the outer beaker and glycerin in the inner tube.

The melting point of the first crop of crystals usually gives definite information
as to the presence or absence of phytosterol but the conclusion indicated should be
confirmed by recrystallizing the crystals from absolute alcohol and again determin-
ing the melting point. If the crystals are pure cholesteryl acetate, the melting point
of the second crop should agree closely with that of the first. If phytosteryl acetate
is present, however, a higher melting point will be noted, as phytosteryl acetate is
less soluble in alcohol than cholesteryl acetate. The melting point of cholesteryl
acetate is 114°C, that of phytosteryl acetate 125°-137°C.

33 Digitonin Method. (Marcusson and Schilling11) — Tentative.

Shake vigorously 50 grams of the oil or fat for 15 minutes in a separatory funnel
with 20 cc. of a 1% solution of digitonin in 95% alcohol by volume. Allow the
mixture to stand for a time until the emulsion separates. The lower or fat layer
should be quite clear while the alcohol layer contains a bulky, flocculent precipitate.
Draw off as much as possible of the fat, avoiding any loss of the precipitate. Add
100 cc. of ether to the alcohol layer and filter the mixture. Wash the precipitate
with ether until free from fat; after drying in the air, transfer it to a tall 50 cc.
beaker, add 2-3 cc. of acetic anhydrid and cover the beaker with a watch glass.
Then boil slowly over a low flame for 30 minutes. After cooling, add 30-35 cc. of
60% alcohol by volume and mix the contents of the beaker thoroughly. Filter
off the alcohol solution and wash the precipitate with 60% alcohol, then dissolve it
on the filter with a stream of hot 80% alcohol by volume from a wash bottle and
set aside the filtrate in a cool place (10°C. or below). After the acetates have
crystallized out of this solution filter them off, recrystallize from absolute alcohol,
dry and determine the melting point of each crop of crystals, as directed under 32.

34 UNSAPONTFIABLE RESIDUE12.— TENTATIVE.

Saponify 5 grams of the oil or fat with alcoholic potassium hydroxid solution and
remove the alcohol by evaporation. Wash into a separatory funnel with 70-100 cc.
of water and extract with 50-60 cc. of ether. If the 2 liquids do not separate, add a
few cc. of alcohol. Separate the water solution and wash the ether with water con-
taining a few drops of sodium hydroxid solution. Again extract the soap solution
and washings with ether and evaporate the combined extracts to dryness. In most
cases it is advisable to add a little alcoholic potassium hydroxid solution to the
residue and heat in order to saponify any traces of fats left unsaponified and extract
again with ether. Transfer to a weighed dish and dry as quickly as possible in a
water oven.

Many of the hydrocarbon oils are volatile at 100°C, so that the drying should
not be carried any further than necessary. With resin oil, paraffin wax and the
denser mineral oils there is little danger of loss at 100°C.

On account of the solubility of soap in ether and petroleum ether it is well to
wash the residue with warm water containing a little phenolphthalein. If the
reaction is alkaline, soap is present and the residue must be further purified.

XXIII] FATS AND OILS 313

RESIN OIL.

35 Qualitative Test. — Tentative.

Polarize the pure oil, or a definite dilution with petroleum ether, in a 200 mm.
tube. Resin oil has a polarization in a 200 mm. tube of from + 30° to + 40° on the
sugar scale (Schmidt and Haensch) while most oils13 read between + 1° and —1°.

COTTONSEED OIL.

36 Halphen Test1*.— Official.

Mix carbon disulphid, containing about 1% of sulphur in solution, with an equal
volume of amyl alcohol. Mix equal volumes of this reagent and the oil under ex-
amination, and heat in a bath of boiling, saturated brine for 1-2 hours. In the
presence of as little as 1% of cottonseed oil, a characteristic red or orange-red color
is produced.

Lard and lard oil from animals fed on cottonseed meal will give a faint reaction"
their fatty acids also give this reaction.

The depth of color is proportional, to a certain extent, to the amount of oil pres-
ent, and by making comparative tests with cottonseed oil some idea as to the
amount present can be obtained. Different oils react with different intensities, and
oils which have been heated from 200°-210°C.15 react with greatly diminished in-
tensity. Heating 10 minutes at 250°C. renders cottonseed oil incapable of giving
the reaction16.

PEANUT OIL.

37 Modified Renard Test11. — Tentative.

Weigh 20 grams of the oil into an Erlenmeyer flask. Saponify with alcoholic
potash solution, neutralize exactly with dilute acetic acid, using phenolphthalein
as an indicator, and wash into an 800-1000 cc. flask containing a boiling mixture of
100 cc. of water and 120 cc. of 20% lead acetate solution. Boil for a minute and
then cool the precipitated soap by immersing the flask in water, occasionally
giving it a whirling motion to cause the soap to stick to the sides of the flask. After
the flask has cooled, decant the water and excess of lead acetate solution and wash
the lead soap with cold water and 90% alcohol by volume. Add 200 cc. of ether,
cork and allow to stand for some time until the soap is disintegrated; heat on a
water bath, using a reflux condenser, and boil for about 5 minutes18. In the case of
oils, most of the soap will be dissolved, while in lards, which contain much stearin,
part of the soap will be left undissolved. Cool the ether solution of soap to 15°-
17°C. and allow to stand until all the insoluble soaps have separated out (about 12
hours).

Filter upon a Biichncr funnel and thoroughly wash the insoluble lead soaps
with ether. Wash the ether-insoluble lead soaps into a separatory funnel by means
of a jet of ether, alternating at the end of the operation, if a little of the soap sticks
to the paper, with hydrochloric acid (1 to 3). Add sufficient hydrochloric acid (1 to 3)
so that the total volume of the latter amounts to about 200 cc. and enough ether to make
the total volume of it 150-200 cc. and shake vigorously for several minutes. Allow the
layers to separate, run off the acid layer, and wash the ether once with 100 cc. of dilute
hydrochloric acid and then with several portions of water until the water washings
are no longer acid to methyl orange. If a few undecomposed lumps of lead soap re-
main (indicated by solid particles remaining after the thin! washing with water),
break these up by running off almost all the water layer and then a add little concen-
trated hydrochloric acid, shake and then continue the washing with water as before.

314 .METHODS OF ANALYSIS [Chap.

Distil the ether from the solution of insoluble fatty acids and dry the latter in the
flask by adding a little absolute alcohol and evaporating on a steam bath. Dissolve
the dry fatty acids by warming with 100 cc. of 90% alcohol by volume and cool
slowly to 15°C, shaking to aid crystallization. Allow to stand at 15°C. for 30
minutes. In the presence of peanut oil, crystals of arachidic acid will separate from
the solution. Filter, wash the precipitate twice with 10 cc. of 90% alcohol by
volume, and then with 70% alcohol by volume, care being taken to maintain the
arachidic acid and the wash solutions at a definite temperature in order to apply
the solubility corrections given below. Dissolve the arachidic acid upon the filter
with boiling absolute alcohol, evaporate to dryness in a weighed dish, dry and
weigh. Add to the weight 0.0025 gram for each 10 cc. of 90% alcohol used in the
crystallization and washing, if conducted at 15°C. ; if conducted at 20°C, add 0.0045
gram for each 10 cc. The melting point of arachidic acid thus obtained is 71°-
72°C. Twenty times the weight of arachidic acid will give the approximate amount
of peanut oil present. Arachidic acid has a characteristic appearance and may
be identified by the microscope. As little as 5-10% of peanut oil can be detected
by this method.

SESAME OIL.

38 Baudoin Test. — Official.

Dissolve 0.1 gram of finely powdered sugar in 10 cc. of hydrochloric acid (sp.
gr. 1.20), add 20 cc. of the oil to be tested, shake thoroughly for a minute and allow
to stand. The aqueous solution separates almost at once and, in the presence of
even a very small admixture of sesame oil, is colored crimson. Some olive oils
give a slight pink coloration with this reagent. Comparative tests with known
samples containing sesame oil will differentiate them.

39 Villavecchia Test1'.— Official.

Add 2 grams of furfural to 100 cc. of 95% alcohol by volume and mix thoroughly
0.1 cc. of this solution, 10 cc. of hydrochloric acid (sp. gr. 1.20), and 10 cc. of the oil
by shaking them together in a test tube. A crimson color is developed as in the
Baudoin test, 38, where sugar is used.

Villavecchia explained this reaction on the basis that furfural is formed by the
action of levulose and hydrochloric acid and therefore substituted furfural for
sucrose. As furfural gives a violet tint with hydrochloric acid it is necessary to use
the very dilute solution specified in the method.

BEEF FAT IN LARD.

40 Emery Method20.— Tentative.

Weigh 5 grams of the melted fat into a glass-stoppered 25 cc. cylinder about
150-175 mm. in height. Add warm ether up to the 25 cc. mark, stopper securely
and shake until the fat is completely dissolved. Allow the cylinder to stand for
about 18 hours at a temperature of 16°-20°C. during which time some of the solid
glycerides will crystallize out. Decant the clear solution carefully from the crys-
tals, wash with three 5 cc. portions of cold ether, avoiding breaking up the deposit
during the first 2 washings. Agitate the crystals with the third portion of ether
and transfer to a small filter. Wash on the paper with successive small amounts
of cold ether until 15-20 cc. have been used, then remove the last traces of ether by
means of slight suction on the stem of the funnel. Break up any large lumps and
allow the deposit to dry.

XXIII] FATS AND OILS 315

When thoroughly dry pulverize the glycerides and take their melting point in a
closed 1 mm. tube, using an apparatus similar to that indicated in 1 1 , Fig. 12. Heat
the water in the beaker rapidly to about 55°C. and maintain that temperature
until the thermometer carrying the melting-point tube registers 50°-55°C., then
heat again and carry the temperature of the outer bath somewhat rapidly to 67°C.
when the lamp is removed. The melting point of the crystals is regarded as that
point when the fused substance becomes perfectly clear and transparent. A dark
background placed about 4 inches from the apparatus will prove of advantage.
When the melting point of the glycerides obtained by this method is below 63.4°C.
the presence of beef fat should be suspected, while a melting point of 63°C, or below,
can be regarded as positive evidence that the sample is not pure lard. It is advis-
able to carry out this method with a control sample of pure lard in connection with
each batch of samples analyzed.

FISH OIL AND MARINE ANIMAL OILS IN THE PRESENCE OF VEGETABLE OILS AND IN THE
ABSENCE OF METALLIC SALTS.

41 Qualitative Test. — Tentative.

Dissolve in a test tube about 6 grams of the oil in 12 cc. of a mixture of equal
parts of chloroform and glacial acetic acid. Add bromin, drop by drop, until a
slight excess is indicated by the color, keeping the solution at about 20°C. Allow
to stand 15 minutes or more and then place the test tube in boiling water. If vege-
table oils only are present, the solution will become perfectly clear, while fish oils
will remain cloudy or contain a precipitate due to the presence of insoluble bromids.

42 COLORING MATTERS.-TENTATIVE.
Proceed as directed under XI, 3.

BIBLIOGRAPHY.

1 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 2:50.

2 Wiley. Principles and Practice of Agricultural Analysis. 2nd ed., 1906-14, 3:
414; Conn. Agr. Exp. Sta. Rept., 1900, (II), p. 142.

3 Ber., 1882, 15: 1031; J. Am. Chem. Soc, 1899, 21: 991.
* J. Soc. Chem. Ind., 1898, 17: 1021.

*U. S. Bur. Chem. Bull. 13 (IV), p. 448; Lewkowitsch. Chemical Technology
and Analysis of Oils, Fats and Waxes. 5th ed., 1913-15, 1 : 319; Wiley. Principles and
Practice of Agricultural Analvsis. 2nd ed., 1906-14, 3: 390.

6 Arb. kais. Gesundh., 1903-04, 20: 545.

7 Lewkowitsch. Chemical Technology and Analvsis of Oils, Fats and Waxes.
5th ed., 1913-15,2: 425.

8 Analyst, 1889, 14: 61; J. Am. Chem. Soc, 1893, 15: 110.

9 J. Soc. Chem. Ind., 1897, 16:503; Benedikt. Analyse der Fette und Wachs-
arten. 5th ed., 1908, p. 143; Allen. Commercial Organic Analysis. 4th ed., 1909-14,
2: 33.

' 10 U. S. Bur. Animal Industry Circ. 212.

11 Chem. Ztg., 1913, 37: 1001.

12 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 2:79.

13 Lewkowitsch. Chemical Technology and Analysis of Oils, Fats and Waxes.
5th ed., 1913-15, 1: 313.

" J. pharm. chim., 1897, 6th ser., 6: 390; Abs. Analyst, 1897, 22: 326; Allen. Com-
mercial Organic Analysis. 4th ed., 1909-14,2:135; Conn. Agr. Exp. Sta. Rept., 1900
(II), p. 143.

18 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 2: 135.

1G Abs. J. Soc. Chem. Ind., 1899, 18: 711.

17 Compt. rend., 1S71, 73: 1330; Lewkowitsch. Chemical Technology and Analy-
sis of Oils, Fats and Waxes. 5th ed., 1913-15, 2: 310.

18 J. Am. Chem. Soc, 1893, 16: 110.

19 J. Soc. Chem. Ind., 1893, 12: 67; 1894, 13: 69.
" U. S. Bur. Animal Industry Circ. 132.

XXIV. SPICES AND OTHER CONDIMENTS.

SPICES.

1 PREPARATION OF SAMPLE.— TENTATIVE.

Grind the sample so as to pass through a sieve having circular openings 1 mm. in
diameter and mix thoroughly. Owing to the lack of uniformity of most spices
and the peculiar tendency to stratify, extreme care is necessary in weighing out a
portion for analysis. Stir the material with a spoon, having a capacity of approxi-
mately 2 grams, and dip a spoonful from the interior in order that only a very small
amount needs to be added to or taken from the portion on the scale pan. In the
determination of starch in spices by the diastase method, reduce a portion of the
sample to an impalpable powder by grinding in a mortar.

2 MOISTURE.— TENTATIVE.

Dry 2 grams to constant weight at 110°C. From the resulting loss in weight
subtract the amount of volatile ether extract as determined in 9.

3 ASH.— OFFICIAL.
Determine as directed under VIII, 4.

4 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE.
Proceed as directed under TK, 17, employing the ash obtained in 3.

5 ASH INSOLUBLE IN ACID— TENTATIVE.

Boil the water-insoluble residue, obtained in 4, or the total ash obtained in 3,
with 25 cc. of 10% hydrochloric acid (sp. gr. 1.050) for 5 minutes, collect the insol-
uble matter on a Gooch or an ashless filter, wash with hot water, ignite and weigh.

6 CALCIUM OXID IN ASH— OFFICIAL.

Ignite 2-4 grams of the sample as directed under 3, digest with hot 10% hydro-
chloric acid, evaporate to dryness, moisten the dry residue with dilute hydro-
chloric acid and again evaporate to dryness to render the silica insoluble. Moisten
the residue with 5-10 cc. of hydrochloric acid, add about 50 cc. of water, allow to
stand on a water bath for a few minutes, filter and wash the insoluble residue with
hot water. Determine calcium oxid in the combined filtrate and washings as directed
under XXVIII, 23.

7 NITROGEN.-OFFICIAL.

Determine as directed under I, 18, 21 or 23, except in the case of black and
white peppers in which use only the Kjeldahl-Gunning-Arnold method1 [I, 23].
employing 1 gram of the sample.

NITROGEN IN NON-VOLATILE ETHER EXTRACT.

8 Winton, Ogden and Mitchell Method. — Tentative.

(For black and white peppers.)

Extract 10 grams of the pepper for 20 hours in a continuous extraction apparatus
with absolute ether, collecting the extract in a weighed 250 cc. flask. Evaporate

317

318 METHODS OF ANALYSIS [Chap.

the ether, dry first at 100°C. and finally to constant weight at 110°C. Determine
the nitrogen in the weighed extract, as directed in I, 23, digesting in the same flask
used for the extraction. Calculate the parts of nitrogen per 100 parts of non-vola-
tile ether extract. If desired, crude piperin may be calculated from the nitrogen
by multiplying by 20.36.

9 VOLATILE AND NON-VOLATDLE ETHER EXTRACT2.— TENTATIVE.

Extract 2 grams of the ground material for 20 hours in a continuous extrac-
tion apparatus with anhydrous ether [VIII, 9]. Transfer the ethereal solution to
a tared capsule and allow to evaporate at room temperature. Let stand for 18
hours over sulphuric acid and weigh the total ether extract. Heat the extract
gradually and then to constant weight at U0°C. The loss is volatile ether extract;
the residue, non-volatile ether extract.

10 ALCOHOL EXTRACT3.-TENTATIVE.

Place 2 grams of the sample in a 100 cc. flask and fill to the mark with 95% alcohol
by volume. Stopper, shake for 8 hours at 30 minute intervals and allow to
stand for 16 hours longer without shaking. Filter the extract through a dry
filter, evaporate a 50 cc. aliquot of the filtrate to dryness in a flat-bottomed dish
on a water bath and heat to constant weight at 110°C.

1 1 COLD-WATER EXTRACT.— TENTATIVE.

(For ginger.)

Place 4 grams of the sample in a 200 cc. graduated flask, add water to the mark,
shake at 30 minute intervals during 8 hours and let stand 16 hours longer with-
out shaking. Filter and evaporate a 50 cc. aliquot of the filtrate to dryness in a
flat-bottomed, metal dish. Dry to constant weight at 100°C.

12 COPPER-REDUCING SUBSTANCES BY DIRECT INVERSION.— TENTATIVE.

Extract 4 grams of the sample with 5 successive portions of 10 cc. of ether on a
filter that will retain completely the smallest starch granules. After the ether
has evaporated, wash with 150 cc. of 10% alcohol by volume.

Owing to the formation of a glutinous mass which clogs the filter, it is not possible
to wash samples of Batavia cassia with water or dilute alcohol. Therefore all pre-
liminary washing is best omitted in determinations made on all varieties of cassia,
as well as on cassia buds and cinnamon.

Carefully wash the residue from the paper into a 500 cc. flask with 200 cc. of
water, using a small wash bottle, and gently rubbing the paper with the tip of the
finger. Hydrolyze and determine the copper reducing material as directed under
VIII, 60. Express the result in terms of starch.

1 3 STARCH.— TENTATIVE.

Extract 4 grams of the finely pulverized sample with ether and 10% alcohol by
volume, as directed under 12, and determine starch by the diastase method, as
directed under VIII, 62.

14 CRUDE FD3ER.— TENTATIVE.

Proceed as directed under VIII, 68, and remove all ether extractives by suc-
cessive washings of the dry fiber with ether previous to weighing.

XXIV] SPICES AND OTHER CONDIMENTS 319

1 5 TANNIN.— TENTATIVE.

(For cloves and allspice.)

Extract 2 grams of the sample for 20 hours with anhydrous ether. Boil the
residue for 2 hours with 300 cc. of water, cool, make up to 500 cc. and filter. Measure
25 cc. of this infusion into a 1200 cc. flask, add 20 cc. of indigo solution, 750 cc. of
water and proceed as directed under XVI, 32. One cc. of N/10 oxalic acid is
equivalent to 0.006232 gram of quercitannic acid, or 0.0008 gram of oxygen absorbed.

16 TOTAL SULPHUR— OFFICIAL.

(For mustard.)
Proceed as directed under III, 17.

OLr/E OIL.
(For paprika.)

17 Qualitative Test. — Tentative.

Spread 5 grams of the paprika on a watch glass and dry over sulphuric acid for
at least 12 hours. Measure 250 cc. of anhydrous, alcohol-free ether [VIII, 9] into a
graduated flask on which the mark is situated near the lower end of the neck, and
brush the paprika into it. Place a mark on the neck of the flask at the point where
the meniscus is, and allow to stand for an hour, shaking at 20 minute intervals
during that time. Bring the meniscus back to the mark placed upon the neck, either
by cooling the flask and contents if the level has risen, or by adding absolute ether
if it has fallen; let the solid particles settle and pipette off 100 cc. of the supernatant
liquid, filter through an 11 cm. closely woven paper into a tared, air-dry, 250 cc,
glass-stoppered Erlenmeyer flask that has been counterpoised against a similar
flask; wash the paper with a little absolute ether. Then distil off the solvent and
remove the flask from the bath as soon as the ether ceases to come over. Lay the
flask on its side in a water oven and heat for 30 minutes; cool the open flask for at
least 30 minutes in the air and weigh. Repeat this heating and weighing until the
weight is constant to within 1 mg., 2 heatings usually being sufficient. Note the
per cent of ether extract obtained. If more than 1? hours of heating are required
to obtain constant weight, or if the ether extract becomes colorless, reject it and
start a new determination with freshly purified ether.

Dissolve the ether extract in the flask with 10 cc. of chloroform, add 30 cc. of
Hanus' solution [XXIII, 17 (a)] and proceed as directed under XXIII, 18. allow-
ing 30 minutes for the halogen absorption. Note the iodin number of the ether
extract. The iodin number of pure paprika thus obtained should not be less than

125.

MICROSCOPIC EXAMINATION.-TENTATIVE.

18 GENERAL.

Adulterants of vegetable origin in spices are detected best by means of the mi-
croscope. A general knowledge of vegetable histology and the microscopic appear-
ance of the spices and spice adulterants is essential. Some of the standard works4
on these subjects are listed in the bibliography.

19 REAGENTS.

Of the numerous reagents employed in histological work the following are the
most useful in spice examinations: —

(a) Glycerol solution (1 to /).

(b) Absolute alcohol.

320 METHODS OF ANALYSIS [Chap.

(C) Ether.

(d) Ammonium hydroxid. — The concentrated solution, containing about 30% of
ammonia gas, is used in making Schweitzer's reagent and for some other purposes.
For the turmeric test the concentrated solution should be diluted with 10 parts of
water.

(e) 5% potassium hydroxid solution.

(f) Chloral hydrate solution (8 to 5).

(g) Schultze's mixture. — Crystallized potassium chlorate mixed with nitric acid
as needed.

(h) Iodin-potassium iodid solution. — A solution of 0.05 gram of iodin, 0.2 gram
of potassium iodid in 15 cc. of water.

(i) Chlor-zinc iodin solution. — Dissolve 100 grams of zinc chlorid in 60 cc. of water
and to this add 20 grams of potassium iodid and 0.5 gram of iodin crystals. A few
crystals of iodin should be left in the bottle to insure saturation and allowed to
stand a few hours before using. The chlor-zinc iodin solution, prepared in this
manner, will keep for months. If the color developed in the tissue is too deep a blue,
a very slight dilution of the reagent is advisable.

(j) Millon's reagent. — Prepare as in XV, 9.

(k) 1% ferric acetate or chlorid solution. — Freshly prepared.

(1) Alkanna tincture. — Macerate 20 grams of alkanet root for several days with
100 cc. of alcohol.

(m) Aqueous safranin solution.

(n) 10% hydrochloric acid.

(O) Acetic acid. — Glacial or 99% acetic acid diluted with 2 parts of water.

20

APPARATUS.

(a) Dissecting microscope or hand lens.

(b) Compound microscope. — Provided with § and | inch objectives, 1 and 2 inch
oculars, double nosepiece. eyepiece micrometer and polarizing apparatus.

(C) Sieves. — A series of sieves with meshes ranging from 0.2-2 mm.
(d) Slides, cover-glasses, needles, scalpels, forceps, etc.

21

PREPARATION OF SAMPLE.

Reduce one portion to a fine powder in a mortar. Separate another portion into
several grades of fineness by sieves of different mesh or by jarring on a sheet of
paper. In the coarser grades, fragments of a suspicious nature may often be seen
with the naked eye or under a simple microscope; these should be picked out for
subsequent examination under the compound microscope.

22

EXAMINATION'.

Mount a small quantity of the ground sample in water and examine under the
compound microscope with both ordinary and polarized light. This gives general
information as to the nature of the material and serves for the detection and iden-
tification of starch granules and various tissues. Draw a small drop of the iodin-
potassium iodid solution into the same preparation by means of a piece of filter
paper placed on the opposite edge of the cover-glass and examine. Starch gran-
ules will be colored blue or blue-black, cellulose yellow, and proteins either brown
or yellow.

In the manner just described draw a little of the 5% potassium hydroxid solution
under the cover-glass and again examine. This treatment gelatinizes the starch

XXIV] SPICES AND OTHER CONDIMENTS 321

granules, dissolves the proteins, saponifies the fats, and in other ways clears the
preparation. It also imparts to tannins a reddish color. If this treatment does
not clear the tissues satisfactorily, treat a fresh portion for some hours with the
chloral hydrate solution.

Examine also the crude fiber obtained in the chemical analysis, as in this mate-
rial the stone cells and other tissues are shown distinctly.

To isolate stone cells, bast fibers and other thick-walled cells macerate a por-
tion of the sample in Schultze's mixture, using such proportion of potassium chlor-
ate and nitric acid and heating for such a time as secures the desired results. Pow-
dered charcoal and charred shells resist the bleaching action of potash, chloral
hydrate and Schultze's mixture.

If it is desired to distinguish cellulose from infiltrated substances (lignin, suberin,
etc.), add the freshly prepared chlor-zinc iodin solution to a water mount, whereby
the former is colored blue and the latter yellow.

Test for proteins by cautiously warming on a slide with a drop of freshly pre-
pared Millon's reagent. The proteins are partially decomposed, acquiring grad-
ually a brick-red color. If it is desired to study the form of the aleurone (pro-
tein) granules, which in some plants are quite as characteristic as starch granules,
prepare a mount in pure glycerol or oil.

To distinguish fats, oils, essential oils and resins from other cell contents, treat
for an hour with the alkanna tincture, diluted with an equal bulk of water, which
imparts to these substances a deep red color, or treat with ether, which dissolves
them. Treat also with alcohol, which dissolves the essential oils and resins, but
does not perceptibly affect the fats and oils.

In testing for tannins and tissues impregnated with these substances, add the
1% ferric acetate or chlorid solution. Both of these reagents give a green or blue
color with tannins, but the former acts more slowly and is to be preferred.

Crystals of calcium oxalate are recognized by their characteristic forms and
their behavior to polarized light. To distinguish calcium oxalate from calcium
carbonate, treat with acetic acid, which does not affect the former, but dissolves
the latter with effervescence. Both are soluble in hydrochloric acid.

PREPARED MUSTARD.

23 PREPARATION OF SAMPLE.— TENTATIVE.

Transfer the entire contents of the container to a dish sufficiently large to stir
thoroughly and make the whole mass homogeneous. Preserve in a bottle having
a tightly fitting glass stopper. Stir well each time before removing a portion for
analysis.

24 SOLIDS.— TENTATIVE.

Weigh 5 grams of the sample into a flat-bottomed, platinum dish, distribute
evenly over the bottom of the dish with a little water, place on a water bath until
the mixture appears dry, and heat finally to constant weight at 100°C. in a writer
oven.

25 ASH.-OFFICIAL.

Ignite the dry residue, obtained in the determination of solids, 24, as directed
under VIII, 4.

26 SALT— TENTATIVE.
Determine chlorin in the ash as directed under III, 15.

322 METHODS OF ANALYSIS [Chap.

27 ETHER EXTRACT.— TENTATIVE.

Weigh 10 grams of the sample into a capsule and mix with about 30 grams of
sand. Heat on a water bath until the mixture appears dry and complete the dry-
ing in a water oven. Grind until all the lumps are broken up, and determine the
ether extract as directed under VIII, 10.

28 PROTEIN.— OFFICIAL.

Determine the nitrogen as directed under I, 18, 21 or 23, using 5 grams of the
sample. Multiply the result by 6.25 to obtain the amount of protein.

29 acidity.— tentative:.

Weigh 10 grams of the sample into a 200 cc. graduated flask, make up to the
mark with water, shake, filter through a dry paper and determine the acidity in
100 cc. by titration with N/10 alkali, using phenolphthalein as an indicator. Ex-
press the result as acetic acid. One cc. of N/10 alkali is equivalent to 0.0060 gram
of acetic acid.

30 COPPER-REDUCING SUBSTANCES.— TENTATTVE.

By Direct Inversion.

Proceed as directed under VIII, 60, except that 10 grams of the sample, without
previous washing or extraction, are treated directly with 200 cc. of water and 20 cc.
of 25% t^-drochloric acid and the solution is made up to 250 cc. after neutralizing
and before filtering and drawing off the aliquot. In analyses of samples contain-
ing starch, particular attention should be given that the amount of dextrose
present in the aliquot taken for the reducing sugar determination does not exceed
the maximum permitted for that determination. Calculate the result in terms of
starch.

31 CRUDE FD3ER.— TENTATIVE.

Transfer 8 grams of the sample (equivalent to about 2 grams of dry matter) to a
porcelain or glass mortar. Treat with a little hot 1.25% sulphuric acid and rub into
a uniform thin paste. It is absolutely essential that this paste be uniform in con-
sistency and entirely free from lumps. Rinse the thin mixture into a 500 cc. Erlen-
meyer flask, using a total volume of 200 cc. of the hot 1.25% sulphuric acid for the
entire operation. Proceed as directed under VIII, 68, and remove all the fat, pre-
vious to weighing of the crude fiber, by repeated washings of the dry fiber with
ether.

32 COLORING MATTERS.-TENTATIVE.
Proceed as directed under XI.

33 PRESERVATrVES.-TENTATrVE.
Proceed as directed under X.

TOMATO PRODUCTS.

34 PREPARATION OF SAMPLE.-TENTATIVE.

Shake the package and contents thoroughly to incorporate any sediment, then
transfer the entire contents of the container to a large glass or porcelain dish and
mix thoroughly, continuing the stirring for at least 1 minute. Transfer the well
mixed sample to a glass-stoppered container and shake or stir thoroughly each time
before removing portions for analysis.

XTV] SPICES AND OTHER CONDIMENTS 323

5 TOTAL SOLIDS.— TENTATIVE.

Weigh 10 grams of the sample into a flat-bottomed, platinum dish having a diam-
eter of about 6 cm., spread the sample in a thin layer, evaporate to dryness on a
steam bath and dry in a water oven for 4 hours.

36 INSOLUBLE SOLIDS.-TENTATIVE.

Wash 20 grams of the sample repeatedly with hot water, centrifugalizing after
each addition of water and pouring the clear, supernatant liquid through a tared
triple filter paper on a Btichner funnel. After 4-5 washings transfer the remaining
insoluble matter to the filter, dry for 2 hours at 100°C.) cool in a desiccator and
weigh rapidly. The paper used should be dried for 2 hours at 100°C, cooled in a
desiccator and weighed. A cylinder, 1-1 \ inches in diameter and 5-6 inches long,
is convenient for washing and centrifugalizing.

37 SOLUBLE SOLIDS.-TENTATIVE.

Subtract the percentage of insoluble solids from the percentage of total solids
to obtain the percentage of soluble solids.

38 SAND.— TENTATIVE.

Weigh 100 grams of the well mixed sample into a 2-3 liter beaker, nearly fill the
beaker with water, and mix the contents thoroughly. Allow to stand 5 minutes
and decant the supernatant liquid into a second beaker. Refill the first with water
and again mix the contents. After 5 minutes more decant the second beaker into
a third, the first into the second, refill and again mix the first. Continue this opera-
tion, decanting from the third beaker into the sink until the lighter material is
washed out from the ketchup. Then collect the sand from the 3 beakers on a tared
Gooch crucible, dry, ignite and weigh. Attention is especially called to the fact
that under "Sand" only the figure obtained by this method should be reported.
The results obtained by the determination of ash insoluble in hydrochloric acid
are not applicable to the determination of sand, since the sand is so unevenly dis-
tributed that reliable results can only be obtained by taking a larger sample than
is possible in the determination of ash.

39 ASH.- OFFICIAL.

Evaporate 10 grains of the sample to dryness on a water bath and ignite as directed
under VIII, 4.

40 ALKALINITY OF THE ASH.-TENTATIVE.

Proceed as directed under XIII, 7. Express the result as the number of cc. of
N/10 acid required to neutralize the ash from 100 grams of the sample.

41 SODIUM CHLORID.-OFFICIAL.

Proceed as directed under III, 15, using either an aliquot of the solution obtained
in 40 or a nitric acid solution of the whole ash.

42 REDUCING SUGARS BEFORE INVERSION.— TENTATIVE.

Weigh 20 grams of the sample into a 200 cc. flask, dilute with about 100 cc. of
water, clarify with a slight excess of neutral lead acetate solution, dilute to the
mark and filter. Remove the excess of lead with anhydrous sodium or potassium
oxalate. Filter and determine reducing sugars as directed under VIII, 25. Ex-
press the result as per cent of invert sugar.

324 METHODS OF ANALYSIS [Chap.

43 REDUCING SUGARS AFTER INVERSION.-TENTATD7E.

Transfer 50 cc. of the filtrate, obtained in 42, to a 100 cc. flask, add 5 cc. of con-
centrated hydrochloric acid and let stand overnight. Nearly neutralize with
sodium hydroxid solution, cool, dilute to the mark and determine reducing sugars
in an aliquot as directed under VIII, 25. Express the result as per cent of invert
sugar.

44 SUCROSE.— TENTATIVE.
Proceed as directed under VIII, 1 8.

45 TOTAL ACIDS.— TENTATIVE.

Proceed as directed under XLX, 17, employing 5 grams of the sample. Express
the result as anhydrous citric acid. One cc. of N/10 alkali is equivalent to 0.0064
gram of anhydrous citric acid.

46 VOLATILE ACIDS.— TENTATIVE.

Proceed as directed under XVI, 27, employing 25 grams of the sample, increas-
ing the amount of water used for the distillation and collecting a correspondingly
larger amount of distillate. Express the result as acetic acid. One cc. of N/10
alkali is equivalent to 0.0060 gram of acetic acid. Reserve the neutralized distillate
for the detection of butyric acid.

BUTYRIC ACID.

47 Qualitative Test. — Tentative.

Evaporate the neutralized distillate, obtained in 46, to dryness on a steam bath.
Decompose the residue with about 5 cc. of 10% sulphuric acid and note the odor.

48 FTXED ACIDS.— TENTATIVE.

Multiply the percentage of volatile acids, 43, by 1.067 and subtract the product
from the percentage of total acids, 45, to obtain the per cent of fixed acids as citric
acid.

Micro-Analysis of Tomato Pulp, Ketchup, Puree and Sauce (Paste).

49 APPARATUS.

(a) Compound microscope. — Giving magnifications of approximately 90, ISO and
500 diameters. These diameters can be obtained by a microscope equipped with
16 and 8 mm. apochromatic objectives and a X6 and a X18 compensating ocular
(a X12 ocular may also be used if desired).

(b) Thoma-Zeiss blood counting cell.

(C) Special Thoma-Zeiss cell. — With the central disk of 19 mm. diameter for
making the mold count5.

50 MOLDS.-TENTATIVE.

Clean the special Thoma-Zeiss cell so that Newton's rings are produced be-
tween the slide and the cover-glass. Remove the cover and place, by means of a
knife blade or scalpel, a small drop of the sample upon the central disk; spread the
drop evenly over the disk and cover with the cover-glass so as to give an even spread
to the material.

XXIV] SPICES AND OTHER CONDIMENTS 325

It is of the utmost importance that the drop be mixed thoroughly and spread
evenly, otherwise the insoluble matter, and consequently the molds, are most abun-
dant at the center of the drop. Squeezing out of the more liquid portions around
the margin must be avoided. In a satisfactory mount Newton's rings should be
apparent when finally mounted and none of the liquid should be drawn across the
moat and under the cover-glass.

Place the slide under the microscope and examine with about 90 diameters and
with such adjustment that each field of view represents approximately 1.5 sq. mm.
of area on the mount.

Observe each field as to the presence or absence of mold filaments and note the
result as positive or negative. Examine at least 50 fields, prepared from 2 or more
mounts. No field should be considered positive unless the aggregate length of the
filaments present exceeds approximately one sixth the diameter of the field. Cal-
culate the proportion of positive fields from the results of the examination of all
the observed fields and report as percentage of fields containing mold filaments.

51 YEASTS AND SPORES.— TENTATIVE.

Fill a graduated cylinder with water to the 20 cc. mark, and then add the sample
till the level of the mixture reaches the 30 cc. mark. Close the graduate, or pour
the contents into an Erlenmeyer flask, and shake the mixture vigorously 15-20 sec-
onds. To facilitate thorough mixing the mixture should not fill more than three
fourths of the container in which the shaking is performed. For tomato sauce or
pastes, or products running very high in the number of organisms, or of heavy con-
sistency, 80 cc. of water should be used with 10 cc. or 10 grams of the sample.
In the case of exceptionally thick or dry pastes, it may be necessary to make an
even greater dilution.

Pour the mixture into a beaker. Thoroughly clean the Thoma-Zeiss counting
cell so as to give good Newton's rings. Stir thoroughly the contents of the beaker
with a scalpel or knife blade, and then, after allowing to stand 3-5 seconds, remove
a small drop and place upon the central disk of the Thoma-Zeiss counting cell and
cover immediately with the cover-glass, observing the same precautions in mount-
ing the sample as given under 50. Allow the slide to stand not less than 10 min-
utes before beginning to make the count. Make the count with a magnification
of about 180 (8 mm. apochromatic objective with the X6 compensating ocular).

Count the number of yeasts and spores on one half of the ruled squares on the
disk (this amounts to counting the number in 8 of the blocks, each of which con-
tains 25 of the small ruled squares). The total number thus obtained equals the num-
ber of organisms in 1/60 cmm. if a dilution of 1 part of the sample with 2 parts of water
is used. If a dilution of 1 part of the sample with 8 parts of water is used,
the number must be multiplied by 3. In making the counts, the analyst should
avoid counting an organism twice when it rests on a boundary line between 2 adja-
cent squares.

52 BACTERIA.-TENTATIVE.

Estimate the bacteria from the mounted sample, used in 51, but. allow t he sample
to stand not less than 15 minutes after mounting before counting. Use a magnifi-
cation of about 500 (8 mm. apochromatic objective and X18 compensating ocular).
Because of the somewhat clearer definition obtained with the X12 compensating
ocular, some prefer it to the X18, though tin' magnification is correspondingly less,
being about 375. Count and record the Dumber of bacteria in a small area consist-
ing of 5 of the small sized squares. Move the slide to another portion of the field

326 METHODS OF ANALYSIS

and count the number on another similar area. Count 5 such areas, preferably 1
from near each corner of the ruled portion of the slide and 1 from near the center.
Determine the average number of bacteria per area and multiply by 2,400,000 which
gives the number of bacteria per cc. If a dilution of 1 part of the sample with
8 parts of water instead of 1 part of the sample with 2 parts of water is used in
making up the sample, then the total count obtained as above must be multiplied
by 7,200,000. Omit the micrococci type of bacteria in making the count.

BIBLIOGRAPHY.

1 Z. anal. Chem., 1892, 31: 525; Conn. Agr. Exp. Sta. Rept., 1898, (II), p. 190.

2 U. S. Bur. Chem. Bull. 13 (II), p. 165.

3 Conn. Agr. Exp. Sta. Rept., 1898, (II), p. 187.

4 Winton. Microscopy of Vegetable Foods. 2nd ed., 1916; Vogl. Die wichtig-
sten vegetabilischen Nahrungs-und Genussmittel. 1899; Tschirch und Oesterle.
Anatomischer Atlas der Pharmakognosie und Nahrungsmittelkunde. 1900; Greenish
and Collin. Anatomical Atlas of Vegetable Powders. 1904; Greenish. Microscopical
Examination of Foods and Drugs. 2nd ed., 1910; Koch. Die Mikroscopische Ana-
lyse der Drogenpulver. 1900-08.

6 U. S. Bur. Chem. Circ. 68, p. 4.

XXV. CACAO PRODUCTS.

1 PREPARATION OF SAMPLE.— TENTATIVE.

Mix powdered products thoroughly and preserve in tightly stoppered bottles.
Chill sweet or bitter chocolate until it becomes hard and reduce to a finely granu-
lar condition by grating or shaving. Mix thoroughly and preserve in a tightly
stoppered bottle in a cool place.

2 MOISTURE.— OFFICIAL.
Proceed as directed under IX, 2.

3 ASH.-OFFICIAL.

Proceed as directed under VIII, 4, employing sufficient sample to contain approxi-
mately 1 gram of water-, sugar- and fat-free material.

4 ASH INSOLUBLE IN ACID.— TENTATIVE.
Proceed as directed under XXIV, 5.

5 SOLUBLE AND INSOLUBLE ASH.-TENTATIVE.

Proceed as directed under IX, 17, employing sufficient sample to contain ap-
proximately 1 gram of water-, sugar- and fat-free material.

6 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE.

Proceed as directed under IX, 18.

7 ALKALINITY OF THE INSOLUBLE ASH.— TENTATIVE.

Proceed as directed under IX, 19.

8 TOTAL NITROGEN.-OFFICIAL.

Determine total nitrogen as directed under I, 18, 21 or 23.

9 CRUDE FIBER.— TENTATIVE.

Proceed as directed under VIII, 68, employing sufficient sample to contain ap-
proximately 1 gram of water-, sugar- and fat-free material, except that both nitra-
tions should be made upon paper, the washed fiber either being weighed upon a
tared filter in the usual way or rinsed from the paper into a tared Gooch, dried and
weighed.

The residue after fat extraction may be used directly for the crude fiber deter-
mination in the analysis of commercial cocoa and other finely ground or pulver-
ized cacao products. If, however, the material is at all granular, it should be re-
duced to an impalpable powder; otherwise the results will be much too high. The
pulverization may be satisfactorily performed by grinding with ether, as described
under 10, treating the extracted residue with the hot 1.25% sulphuric acid and
proceeding from this point as directed above.

327

328 METHODS OF ANALYSIS [Chap

STARCH.

10 Direct Acid Hydrolysis. — Tentative.

Weigh 4 grams of the sample, if unsweetened, or 10 grams if sweetened, into a
small porcelain mortar, add 25 cc. of ether and grind. After the coarser material
has settled, decant the ether, together with the fine suspended matter, onto an 11
cm. paper of sufficiently fine texture to retain the crude starch. Repeat this treat-
ment until no more coarse material remains. After the ether has evaporated from
the filter, transfer the fat-free residue to the mortar by means of a jet of cold water
and rub to an even paste, filtering on the paper previously employed. Repeat this
process until all the sugar is removed. In the case of sweetened products the fil-
trate should measure at least 500 cc. Determine crude starch in the extracted
residue as directed under VIII, 60.

11 Diastase Method. — Tentative.

Remove fat and sugar from 4 grams of the sample, if unsweetened, or 10 grams if
sweetened, as directed under 10. Wash carefully the wet residue into a beaker with
100 cc. of water, heat to boiling over asbestos with constant stirring and continue
the boiling and stirring for 30 minutes. Replace the water lost by evaporation and
immerse the beaker in a water bath kept at 55°-60°C. When the liquid has cooled
to the temperature of the bath, add 20 cc. of freshly prepared malt extract [VIII,
61 ] and digest the mixture for 2 hours with occasional stirring. Boil a second
time for 30 minutes, dilute, cool and digest as before with another 20 cc. portion
of the malt extract. Heat again to boiling, cool and transfer to a 250 cc. flask. Add
3 cc. of alumina cream, make up to the mark and filter through a dry paper. The
residue on the paper should show no signs of starch when examined microscopically.
Continue from this point as directed under VIII, 62, beginning with the words
"Place 200 cc. of the filtrate in a flask with 20 cc. of hydrochloric acid".

12 FAT.— TENTATIVE.

Dry 2 grams of the material over sulphuric acid until all the moisture is practi-
cally removed. (Products rich in fat show a tendency to cake at the temperature
of boiling water. Hence, drying by means of heat must be avoided.) Extract with
anhydrous ether in a continuous extractor until no more fat is removed. Grind
and repeat the extraction. Introduce the ether extract into a tared dish, allow the
ether to evaporate and dry the residue to constant weight at 100°C.

The rapid centrifugal method1, though useful and accurate under ordinary con-
ditions, is unreliable during the summer months or in warm latitudes and has not
been approved.

13 FAT CONSTANTS.-TENTATIVE.

Separate the fat in a manner similar to that described under 15 and determine
the melting point, index of refraction, iodin absorption, saponification, Reichert-
Meissl and Polenske numbers as directed under XXIII. Melting point determi-
nations upon this material do not become normal until the fat has been kept for at
least 24 hours in a cool place.

14 MILK FAT IN MILK CHOCOLATE.— TENTATIVE.

Estimate the amount of milk fat in milk chocolate from the following formula
based on a Reichert-Meissl number of 0.5 for cocoa butter:

XXV] CACAO PRODUCTS 329

„ 24A + 0.5B . , . .

O = in which

5

A = grams of butter fat in 5 grams of mixed fat;

B = 5 — A = grams of cocoa fat in 5 grams of mixed fat;

C = Reichert-Meissl number of extracted fat.

From which the

C — 0. 5

Weight of butter fat in 5 grams of mixed fat = - and the

4.7

q q 5

Per cent of butter fat = per cent of total fat X -

23.5

15 SUCROSE AND LACTOSE.— TENT ATD7E.

Prepare the sample by chilling well and shaving as finely as possible with a knife.
Transfer 26 grams of this material to an 8 ounce nursing bottle, add about 100 cc.
of petroleum ether and shake for 5 minutes. Centrifugalize until the solvent is
clear. Draw off the same by suction and repeat the treatment with petroleum
ether. Place the bottle containing the de-fatted residue in a warm place until the
residual traces of petroleum ether are practically expelled. Add 100 cc. of water,
shake until all the chocolate is loosened from the sides and bottom of the bottle
and then shake for 3 minutes longer. Add basic lead acetate solution from a burette
to complete precipitation, then sufficient water to make the total volume of liquid
110 cc. Mix thoroughly and filter through a folded filter. Make the direct polari-
scopic reading "a" in a 200 mm. tube. Precipitate the excess of lead by anhydrous
potassium oxalate and invert the solution as directed under VIII, 14. Obtain
the reading of the inverted solution. Multiply the invert reading by 2 to correct
for dilution "b". From the figures obtained calculate the percentages of sucrose
(S) and lactose (L) by the formulas

g = (a-b) (110 + x)

142.66- |

a(l.l+-^)-S

L = - — - in which the value of x is obtained from

0.79

0.2244 (a-21d) . , . , ., , . , . .. . . ,

x = - — nnnn. , n+ i in which the value of d is obtained from

1 - 0.00204 (a - 21d)

, a— b

a = —

142.66- r2

16 CASEIN IN MILK CHOCOLATE.-TENTATD7E.

It is unnecessary to de-fat the chocolate. Weigh 10 grams of the chocolate
into a 500 cc. Erlenrneyer flask and add 250 cc. of 1% sodium oxalate solution, i leal
to boiling and boil gently for a few minutes, then cool, add 5 grams of magnesium
carbonate and filter. Determine nitrogen in 50 cc. of this filtrate. Pipette 100 cc.
of the filtrate into a 200 cc. volumetric flask and dilute almost to the mark with
water. Then precipitate the casein by the addition of 2 cc. of glacial acetic acid
or 1 cc. of concentrated sulphuric acid. Make to volume, shake, filler and deter-
mine nitrogen in 100 cc. of the filtrate. The difference between the 2 nitrogen de-
terminations gives the nitrogen derived from the casein which, multiplied l>y <i.:>S,
gives the amount of casein present in 2 grams of the sample.

330

METHODS OF ANALYSIS

17 COLORING MATTERS.— TENTATIVE.

Proceed as directed under XI.

BIBLIOGRAPHY.
1 U. S. Bur. Chem. Bull. 137, p. 103.

XXVI. COFFEES.

GREEN COFFEE.

1 MACROSCOPIC EXAMINATION— TENTATIVE.

A macroscopic examination is usually sufficient to show the presence of excessiv
amounts of black and blighted coffee beans, coffee hulls, stones and other foreign
matter. These can be separated by hand picking and determined gravimetrically.

2 COLORING MATTERS.-TENTATIVE.

Shake vigorously 100 grams or more of the sample with cold water or 70% alco-
hol by volume. Strain through a coarse sieve and allow to settle. Identify
soluble colors in the solution and insoluble pigments in the sediment as directed
under XI.

ROASTED COFFEE.

3 MACROSCOPIC EXAMINATION.-TENTATIVE.

Artificial coffee beans are apparent from their exact regularity of form. Roasted
legumes and lumps of chicory, when present in whole roasted coffee, can be picked
out and identified microscopically. In the case o!7 ground coffee sprinkle some of
the sample on cold water and stir lightly. Fragments of pure coffee, if not over-
roasted, will float, while fragments of chicory, legumes, cereals, etc., will sink imme-
diately, chicory coloring the water a decided brown. In all cases identify the par-
ticles that sink, by microscopical examination.

4 PREPARATION OF SAMPLE.— TENTATIVE.

Grind the sample and pass through a sieve having holes 0.5 mm. in diameter
and preserve in a tightly stoppered bottle.

5 MOISTURE.-TENTVrrVE.

Dry 5 grams of the sample at 105°-110°C. for 5 hours and subsequent periods of
an hour each until constant weight is obtained. The same procedure may be used,
drying in vacuo at the temperature of boiling water. In the case of whole coffee,
grind rapidly to a coarse powder and weigh at once portions for the determina-
tion without sifting and without unnecessary exposure to the air.

SOLUBLE SOLIDS.

6 Winton Method. — Tentative.

Place 4 grams of the sample in a 200 cc. flask, add water to the mark and allow
the mass to infuse 8 hours, with occasional shaking; let stand 16 hours lorvj; r with-
out shaking, filter, evaporate 50 cc. of the filtrate to dryness in a Qat-bottomed
dish, dry at 100°C. and weigh.

7 ASH.-OFFICIAL.
Proceed as directed under VIII, 4.

331

332 METHODS OF ANALYSIS [Chap.

8 ASH INSOLUBLE IN ACID. -TENTATIVE.

Proceed as directed under XXIV, 5.

0 SOLUBLE AND INSOLUBLE ASH. -TENTATIVE.

Proceed as directed under IX. 17.

1 0 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE.
Proceed as directed under LX, 18.

1 1 SOLUBLE PHOSPHORIC ACID IN THE ASH.-TENTATD7E.

Acidify the solution of soluble ash, obtained in 9, with dilute nitric acid and
determine phosphoric acid (PaOsJas directed under I, 6 or 9.

1 2 INSOLUBLE PHOSPHORIC ACID IN THE ASH. -TENTATIVE.

Determine phosphoric acid (P2O5) in the insoluble ash as directed under I, 6
or 9.

1 3 CHLORIN.— OFFICIAL.
Proceed as directed under III, 18.

CAFFEIN.

14 Gorier Method1. — Tentative.

Moisten 11 grams of finely powdered coffee with 3 cc. of water, allow to stand
30 minutes and extract with chloroform for 3 hours in a Soxhlet extractor. Evap-
orate the extract, treat the residue of fat and caffein with hot water, filter through
a cotton plug and moistened filter paper and wash with hot water. Make up the
filtrate and washings to 55 cc, pipette off 50 cc. and extract 4 times with chloro-
form. Evaporate the chloroform extract in a tared flask, dry the caffein at 100°C.
and weigh. Transfer the residue to a Kjeldahl flask with a small amount of hot
water and determine nitrogen as directed in I, 18, 21 or 23. To obtain the weight
of caffein multiply the result by 3.464.

15 Modified Stahlschmidt Method2. — Tentative.

^Yeigh 3.125 grams of the finely powdered sample into a 500 cc. flask, add 225 cc.
of water (this volume will shrink to about 200 cc. by boiling), attach a reflux con-
denser and boil for 2 hours. Add 2 grams of dry basic lead acetate [VIII, 13 (C)]
and boil 10 minutes more. Cool, transfer to a 250 cc. graduated flask, fill to the
mark, filter through a dry filter, measure 200 cc. of the filtrate into a 250 cc.
graduated flask and pass hydrogen sulphid through it to remove the excess of lead.
Make the solution up to the mark and filter through a dry filter. Measure 200 cc.
of this filtrate into an evaporating dish and concentrate to about 40 cc. Wash the
concentrated solution with as little water as possible into a small separatory funnel
and shake out 4 times with chloroform, using 25, 20, 15 and 10 cc, respectively. If
any emulsion forms, break it up with a stirring rod and run the separated portions of
chloroform through a 5 cm. filter paper into a small, tared Erlcnmeyer flask. Evap-
orate off the chloroform on the steam bath, or recover the chloroform by attaching
the flask to a condenser and distilling to a small volume. Dry the fine, white crystals
of caffein to constant weight at 75°C. Test the purity of this residue by deter-
mining nitrogen as directed in I. 18, 21 or 23 and multiplying by the factor 3.464.

XXVI] COFFEES 333

16 CRUDE FIBER.— TENTATIVE.

Proceed as directed under VIII, 68.

1 7 STARCH.— TENTATIVE.

Extract 5 grams of the finely pulverized sample on a hardened filter with 5 suc-
cessive portions (10 cc. each) of ether; wash with small portions", of 95% alcohol
by volume until a total of 200 cc. have passed through, place the residue in a
beaker and proceed as directed under VIII, 62.

1 8 SUGARS.— TENTATIVE.

Proceed as directed under VIII, 58 and 59.

1 9 PETROLEUM ETHER EXTRACT.-TENTATIVE.

Dry 2 grams of the coffee at 100°C, extract with petroleum ether (b. p. 35°-50°C.)
for 18 hours, evaporate the solvent, dry the residue at 100°C. and weigh.

20 TOTAL ACIDITY.— TENTATIVE.

Treat 10 grams of the sample, prepared as directed under 4, 'with 75 cc. of 80%
alcohol by volume in an Erlenmeyer flask, stopper and allow to stand 16 hours,
shaking occasionally. Filter and transfer an aliquot of the filtrate (25 cc. in the
case of green coffee, 10 cc. in the case of roasted coffee) to a beaker, dilute to about
100 cc. with water and titrate with N/10 alkali, using phenolphthalein as an indi-
cator. Express the result as the number of cc. of X/10 alkali required to neutralize
the acidity of 100 grams of the sample.

21 VOLATILE ACIDITY. -TENTATIVE.

Into a volatile acid apparatus [XVI, 27; Fig. 8] introduce a few glass beads and
over these place 20 grams of the unground sample. Add 100 cc. of recently boiled
water to the sample, place a sufficient quantity of recently boiled water in the outer
flask and distil until the distillate is no longer acid to litmus paper (usually 100 cc.
of distillate will be collected). Titrate the distillate with N/10 alkali, using phenol-
phthalein as an indicator. Express the result as the number of cc. of N/10 alkali
required to neutralize the acidity of 100 grams of the sample.

Coating and Glazing Substances.

22 sugar and dextrin. -tentative.

Introduce 100 grams of the whole coffee into a beaker, add exactly 300 cc. of
water, stir and allow to stand 5 minutes, with frequent stirring. Filter through a
dry paper, add carefully to the filtrate sufficient dry lead acetate to precipitate
all the caffetannic acid, avoiding an excess. Filter through dry paper and re-
move the lead from the filtrate by the addition of a slight excess of anhydrous
potassium oxalate. Filter through a dry paper and determine reducing sugars as
invert sugar in 50 cc. of the filtrate, as directed in VIII. 25. Inverl a 75 cc. aliquot
of the filtrate as directed under VIII, 14. Cool, nearly neutralize with sodium
hydroxid solution, make up to 100 cc. and determine reducing sugars as invert supr
in the resulting solution, as direel< d under VIII. 25. Measure a KM) cc. aliquot
of the filtrate into a 200 cc. flask, add 10 cc. of '_'">' ; hydrochloric acid and liv-
drolyze as directed under VIII, 60. Cool, neutralize with sodium hydroxid solu-
tion, make up to volume, filter through a dry paper and determine reducing BUgars
as invert sugar in 50 cc. of the lilt rale as directed under VIII. 25. Calculate the

334 METHODS OF ANALYSIS

reducing sugars in each instance to per cent by weight of the original coffee. Cal-
culate sucrose from the reducing sugars before and after inversion as directed in
VIII, 18, and calculate dextrin as follows: Subtract the reducing sugars after in-
version from the reducing sugars after hydrolysis, multiply the difference by the
factor 0.9561 to convert the result to dextrose and then by 0.9 to convert to dextrin.
In some instances the presence of sucrose in the water extract may be verified
by polarization. The presence of dextrin in the water extract may be verified by
polarization as directed under LX, 25, and by the erythro-dextrin test [LX, 47]
performed on the water extract previous to clarification with lead acetate.

23 EGG ALBUMEN AND GELATIN.— TENTATIVE.

Treat 100 grams of the whole coffee with 500 cc. of water and allow to stand with
frequent stirring for 5 minutes. Filter and treat separate portions of the filtrate
with (1) a strong solution of tannic acid; (2) Millon's reagent [XV, 9]; (3) by
boiling. In the presence of egg albumen a more or less heavy precipitate will
be formed in each case. As a confirmatory test, treat an aliquot of the filtrate with
an excess of tannic acid solution, add a little salt if necessary to secure flocculation
of the precipitate, filter and, without washing, introduce the paper and its con-
tents into a Kjeldahl flask and determine nitrogen. By this method coffee not
coated with albumen or gelatin will yield less than 10 mg. of nitrogen per 100 grams
of sample.

24 CHICORY INFUSION.— TENTATD7E.

Cover 100-150 grams of the whole coffee with water, allow to soak 2-3 minutes,
stirring frequently, and drain the aqueous washings through a coarse sieve. Wash
the coffee upon the sieve with about 100 cc. of water and centrifugalize the com-
bined washings. Decant the clear liquid from the sediment, drain almost dry upon
filter paper, then mount the sediment in chloral hydrate [XXIV, 20 (f )] and exam-
ine under the microscope for elements of chicory.

FATS AND WAXES.

25 Spdth Method3. — Tentative.

Treat 100-200 grams of the beans with low boiling petroleum ether for 10 min-
utes, pour off the petroleum ether and repeat the process. Filter the combined
petroleum ether extracts, evaporate and determine the index of refraction and the
saponification number of the residue, as directed under XXIII, 6 and 20.

BIBLIOGRAPHY.

1 Ann., 1908, 358:327.

2 Allen. Commercial Organic Analysis. 4th ed., 1909-14, 6: 607.

3 Forschb. iiber Lebensm., 1895, 2: 223.

XXVII. TEA.

1 DUST, STEMS AND FOREIGN LEAVES.— TENTATIVE.

Place 1 gram of the tea in a 300 cc. casserole, add 200 cc. of boiling water and
allow to stand 15 minutes. This treatment will cause the leaves to unroll, and a
macroscopic examination will reveal the presence or absence of dust or stems, while
the leaves will be in condition for examination as to their form and structure1.

2 PREPARATION OF SAMPLE.-TENTATTVE.

Grind the sample and pass it through a sieve having circular openings 0.5 mm.
in diameter.

3 MOISTURE.— TENTATIVE.
Proceed as directed under IX, 2.

4 WATER EXTRACT2.— TENTATIVE.

To 2 grams of the original sample in a 500 cc. Erlenmeyer flask add 200 cc. of hot
water and boil over a low flame for an hour. The flask should be closed with a rub-
ber stopper through which passes a glass tube 18 inches long for a condenser. The
loss from evaporation should be replaced from time to time by the addition of
hot water. Filter through a tared filter and wash the residue until the filtrate meas-
ures 500vcc, stirring the contents of the filter throughout the process to facilitate
the filtering. Dry the filter paper and residue in the funnel in the steam oven until
the excess of water is removed, transfer paper and contents to a tared weighing
bottle and dry to constant weight at 100°C.

5 ASH.-OFFICIAL.
Proceed as directed under VIII, 4.

6 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE.

Proceed as directed under IX, 17.

7 ASH INSOLUBLE IN ACID.-TENTATTVE.
Proceed as directed under XXIV, 5.

8 ALKALINITY OF THE ASH.-TENTATIVE.

Determine the alkalinity of the soluble and insoluble ash as directed under IX,
18 and 19.

9 PHOSPHORIC ACID IN THE ASH.-TENTATIVE.

Determine phosphoric acid (P206) in the soluble and insoluble ash as directed
under XXVI, 11 and 12.

10 PETROLEUM ETHER EXTRACT.-TENTATIVE.
Proceed as directed under XXVI, 19.

335

336 METHODS OF ANALYSIS [Chap.

1 "J PROTEIN.— TENTATIVE.

Determine nitrogen as directed under I, 18, 21 or 23. Subtract the percentage
of nitrogen present as caffein from the percentage of total nitrogen to obtain the
percentage of nitrogen present as protein. Multiply this result by 6.25 to obtain
the percentage of protein.

12 CRUDE FIBER.— TENTATIVE.
Proceed as directed under VIII, 68.

13 VOLATILE OrL.-TENTATIVE.

Add 100 grams of tea to 800 cc. of water, distil, extract the distillate several times
with petroleum ether, transfer the combined petroleum ether extracts to a tared
dish, evaporate at room temperature, dry in a desiccator and weigh.

CAFFEIN.

14 Modified Stahlschmidt Method. — Tentative.
Proceed as directed under XXVI, 15.

TANNIN.
Proctor Modification of the Lowenthal Method3. — Tentative.

1 5 REAGENTS .

(a) Potassium permanganate solution. — Make up a solution containing 1.33 grams
per liter and obtain its equivalent in terms of N/10 oxalic acid.

(b) N/10 oxalic acid.

(C) Indigo carmine solution. — Make up a solution containing 6 grams of indigo
carmine (free from indigo blue) and 50 cc. of concentrated sulphuric acid per liter.

(d) Gelatin solution. — Soak 25 grams of gelatin for an hour in saturated sodium
chlorid solution, heat until the gelatin is dissolved and make up to 1 liter after
cooling.

(e) Acid sodium chlorid solution. — Acidif}' 975 cc. of saturated sodium chlorid solu-
tion with 25 cc. of concentrated sulphuric acid.

(f) Powdered kaolin.

16

DETERMINATION*.

Boil 5 grams of the tea for 30 minutes with 400 cc. of water; cool, transfer to a
500 cc. graduated flask and make up to the mark. To 10 cc. of the infusion, filtered
if not clear, add 25 cc. of the indigo carmine solution and about 750 cc. of water.
Add from a burette the potassium permanganate solution, a little at a time while
stirring, until the color becomes light green, then drop by drop, until the color
changes to bright yellow or to a faint pink at the rim. Designate the number of
cc. of permanganate used as "a".

Mix 100 cc. of the clear infusion of tea with 50 cc. of the gelatin solution, 100 cc.
of the acid sodium chlorid solution and 10 grams of the powdered kaolin, and shake
several minutes in a stoppered flask. After settling decant through a filter. Mix
25 cc. of the filtrate with 25 cc. of the indigo carmine solution and about 750 cc. of
water and titrate with permanganate as before. The number of cc. of permanganate
used subtracted from that obtained above, "a", gives the amount of permanganate
required to oxidize the tannin. One cc. of N/10 oxalic acid is equivalent approxi-
mately to 0.004157 gram of tannin (gallotannic acid).

XXVII] tea 337

Facing.

1 7 general.— tentative.

Mineral pigments may be detected in the ash, or the tea may be shaken up with
a large volume of water, and the water separated from the leaves by a sieve, when
the insoluble mineral substances used in facing will settle and can be removed by
filtration for further examination, as directed under XI, 1 , the catechu and other
soluble substances being in the filtrate.

18 PARAFFIN AND WAXY SUBSTANCES.— TENTATIVE.

Spread a quantity of the tea between 2 sheets of unglazed, white paper and place
thereon a hot iron. Any greasy substance will stain the paper4.

PIGMENTS USED FOR COLORING OR FACING.

19 Read Method5. — Tentative.

Place 60 grams of the tea in a 60 mesh, 5-6 inch sieve, provided with a top. Sift
a small quantity (approximately 0.1 gram) of the dust upon a piece of semi-glazed,
white paper about 8 by 10 inches. To obtain the requisite amount of dust, it is
sometimes necessary to rub the leaf gently against the bottom of the sieve, but this
must not be done until the sieve has been well shaken over the paper. Place the
paper on a plain, firm surface, preferably glass or marble, and crush the dust by
pressing firmly upon it a flat steel spatula about 5 inches long. Repeat the crush-
ing process until the tea dust is ground almost to a powder when particles of color-
ing matter, if present, become visible as streaks on the paper. Brush off the
loose dust and examine the paper by means of a simple lens magnifying 7| diame-
ters. In distinguishing these particles and streaks bright light is essential. In
many cases the character of the pigment is indicated by the behavior of these
streaks when treated with reagents and examined under a microscope. The
crushed particles of natural leaf in either black or green tea appear in such
quantity that there is no chance of mistaking them for coloring or facing material.
This test should be repeated using black, semi-glazed paper for facings such as talc,
gypsum, barium sulphate or clay.

BIBLIOGRAPHY.

1 U. S. Bur. Chem. Bull. 13 (VII); Villiers and Colin. Traite des Alterations et
Falsifications des Substances Alimentaires. 2nd ed., 1909-11.

2 U. S. Bur. Chem. Bull. 105, p. 48.

3 Ibid., 13 (VII), p. 890.

4U. S. Treas. Dept., T. D. 35244, March 23, 1915.

6 Ibid.; Proc. Eighth Intern. Cong. Appl. Chem., 1912, 18: 301.

XXVIII. BAKING POWDERS AND THEIR INGREDIENTS.

1 PREPARATION OF SAMPLE— TENTATIVE.

Remove the entire sample from the package, mix carefully and pass through a
20-40 mesh sieve.

TOTAL CARBON DIOXID.

2 General Method. — Tentative.

Make the determination by the absorption method, employing any apparatus
which gives accurate results when checked with pure calcite. Whatever appara-
tus is chosen, the tubes and materials used for absorbing and drying the carbon
dioxid may be varied according to the preference of the analyst. Use 0.25-1 gram
of sodium or calcium carbonate, according to the amount of absorbent employed,
and in the case of baking powder 0.50-2 grams.

Method Using Knorr's Apparatus. — Tentative.

3 REAGENTS.

(a) 50% potassium hydroxid solution.

(b) Soda lime. — Finely granulated and freed from dust by sifting.

4 APPARATUS.

FIG. 14 KNORR'S APPARATUS FOB 1 BE DETERMINATION OF CARBON DIOXID.

This consists of a flask (.4), fitted by means of a ground-glass joint with a glass
connection through the upper part of which passes a dropping funnel (B), and
joined at the side with a Liebig condenser (L>). The mouth of the dropping funnel

339

340 METHODS OF ANALYSIS [Chap.

(B) is connected by means of a perforated stopper with a soda lime tube (C). The
upper end of the Liebig condenser is connected by a rubber joint with a Geissler
bulb (E), containing sulphuric acid for drying the gas passing into the next Geissler
bulb (F), connected with (E), and containing strong potassium hydroxid solution
(1 to 2). The bulb (F) is connected with a third Geissler bulb (G), containing sul-
phuric acid for the absorption of moisture escaping from F. A fourth Geissler
bulb (H) is attached to G as a precaution to prevent moisture from the air being
absorbed by G. H is connected with an aspirator. Many analysts prefer to re-
place the bulb (F) by 2 U-tubes filled with sifted soda lime.

5 DETERMINATION.

Place 0.5-2 grams of the baking powder, the amount depending upon the per-
centage of carbon dioxid present, in the flask (A), which must be perfectly dry.
Close the flask with the stopper which carries the funnel tube and the tube con-
necting with the absorption apparatus. Weigh separately the Geissler bulbs (F)
and (G) and attach them to the apparatus. If 2 soda lime tubes are employed,
weigh them separately and fill the first anew when the second increases materially
in weight. Nearly fill the funnel tube (B) with hydrochloric acid (sp. gr. 1.1) and
place the soda lime tube (C) in position. Then aspirate air through the Geissler
bulbs at a rate of about 2 bubbles per second. Open the stopper of the funnel and
allow the acid to run slowly into the flask, care being taken that the evolution of
gas be so gradual as not to materially increase the current through the Geissler
bulbs. After all the acid has been introduced, close the stop-cock in B, continue
the aspiration and heat gradually the contents of the flask to boiling. While the
flask is being heated the aspirator tube may be removed, although many analysts
prefer, when using ground-glass joints, to aspirate during the entire operation.
Continue the boiling for a few minutes after the water has begun to condense in
D, then remove the flame, open the stop-cock in tube (J3) and allow tha apparatus
to cool with continued aspiration. Remove the absorption bulbs (F) and (G) and
weigh. The increase in weight is due to carbon dioxid.

Method Using Heidenhain's Apparatus. — Tentative.

6 REAGENTS.

(a) Calcium chlorid. — Use calcium chlorid dehydrated at 200°C, but not fused.
Grind it coarsely in a coffee mill and sift through No. IS wire gauze to remove the
extremely coarse, and through No. 30 wire gauze to remove the very fine, particles.

(b) Soda lime. — Grind and sift the soda lime1 for the weighed tubes as described
above. It should not be too dry, as it must not absorb moisture to a greater degree
than the calcium chlorid.

7 APPARATUS2.

This consists of a cylinder (A), filled with soda lime to remove carbon dioxid
from the air passing through the apparatus. A thick layer of cotton at the upper
end prevents soda lime dust from being carried over. Connect the cylinder (A)
by means of a perforated rubber stopper and a bent glass tube having a stop-cock
(B) and a capillary constriction (C) with a short piece of rubber tubing to which
is attached a short piece of glass tubing (E), fitted with a perforated rubber stopper.
The latter fits tightly into the constriction of the funnel tube (D). The funnel of
the latter is cylindrical in shape, f inch in diameter at the upper end, § inch at the
lower end and 4 inches long, the rubber stopper of E fitting into the constriction.

XXVIII]

BAKING POWDERS

341

The stem of the funnel tube (D) passes through a doubly perforated rubber stopper
almost to the bottom of the evolution flask (F), which is ordinarily of 150 cc.
capacity but, in the case of foaming liquids, may hold 300 cc. Through the second
perforation in the stopper connect the evolution flask (F) with a reflux condenser
(GO, consisting of a \ inch glass tube around which is wound a small lead pipe carry-
ing a current of cold water. To the upper end of the condenser attach a U-tube
containing a little calcium chlorid (to be renewed when it has liquefied) to retain the
bulk of the moisture. Connect this U-tube with a second U-tube (//), filled with
coarse calcium chlorid, and this in turn with a third U-tube (K), filled at / with a 3
inch column of pumice stone impregnated with copper sulphate and completely de-
hydrated at 150°C., the remainder of the tube being filled with fine calcium chlorid.
Connect the U-tube (K) with a bent glass tube having a stop-cock (L) which is
closed when the apparatus is not in use. Next attach the absorption U-tubes (M)
and (A/) which are § inch in diameter and 5 inches long, the first filled mainly with
soda lime but containing a little calcium chlorid at the end where the air current

FIG. 15. HEIDENHAIN'S APPARATUS FOR THE DETERMINATION OF
CARBON DIOXTD.

enters, the second filled one half with soda lime and one half with calcium chlorid,
the latter being placed at the side where the air current leaves. Connect N with
a guard tube (0), filled with calcium chlorid on the side toward N and with soda
lime on the side toward P, the latter being a small U-tube trapped with glycerol to
indicate the passage of the air current. Connect P with a safety bottle (R), to
receive any water which may be sucked back from the aspirator, and connect R
with the aspirator (S), a 4 liter Mariette bottle.

The tubes (M) and (A/) should hold about 20 grams, making the capacity of M
for carbon dioxid almost 1 grain and that of N for moisture 0.2 gram. M should
be refilled when its weight has increased 0.75 gram and N after an increase of 0.1
gram in weight.

Use the best grade of rubber for all connections, applying a (rue of castor oil
as a lubricant. For connections of the weighed tubes use rubber tubing boiled in
weak lye, washed and dried. Apply also a little castor oil, which is thoroughly
wiped off again before connecting the lulling.

Before using the apparatus (ill // and K with carbon dioxid in order to saturate
the alkalinity of the calcium chlorid and exhaust after several hours.

342 METHODS OF ANALYSIS [Chap.

8 DETERMINATION.

In order to find the allowable rapidity of the air current employed during the
determination, proceed as follows : Charge the apparatus exactly as for an analysis
leaving out the carbonate. Begin to aspirate at the rate of about 50 cc. per minute.
After 2 liters have been aspirated weigh the tubes, M and N. If they have lost in
weight, repeat the experiment with 40 cc. per minute, and so on until the weight of
the tubes remains constant. If the work has been done with due precaution, the
first tube should have lost just as much as the second has gained. Do not exceed the
safe speed thus found.

Weigh the tubes M and N at the air temperature of the balance room. Shortly
before weighing open the tubes for a moment to allow equalization of air. Note
the thermometer and barometer readings. Connect the tubes with the apparatus
and test the tightness of the joints by closing A at the bottom, opening all the cocks,
starting the aspirator, and observing P, in which the liquid should soon come to a
standstill. Then disconnect the aspirator, close B, remove F, put in the substance,
using about 1 gram of sodium carbonate or calcium carbonate or about 2 grams of
baking powder, connect F, and start the condenser (G). Introduce 50 cc. of 10%
hydrochloric acid through D, lifting E slightly and allowing only small quantities
of the dilute acid to enter at a time. Light the burner under F, heat to boiling
and reduce the flame to keep the liquid just at the boiling point. If no more air
passes P, start the aspiration. When the water stops running from S, open B care-
fully and adjust the outflow of the aspirator by raising or lowering the syphon to
one half the safe speed.

After M has become cool increase the current to the full safe speed and aspirate
altogether 3 liters, continuing boiling to the end of the aspiration. After the tubes
have assumed the temperature of the balance room, open for a moment and weigh.
When extreme accuracy is desired, note again the thermometer and barometer
readings and apply correction according to the following formula:

-(A2 - A1) X T and + (B2 - B1) X B in which

A1 = the temperature at first weighing in degrees C. ;
A2 = the temperature at second weighing in degrees C;
B1 = the air pressure at first weighing in mm. ;
B2 = the air pressure at second weighing in mm.;

T and B are constants found from the following formulas:

T = V X 0.0000039 gram;

B = V X 0.0000015 gram in which

0.0000039 = change in weight of 1 cc. of air for 1°C;
0.0000015 = change in weight of 1 cc. of air for 1 mm. pressure;

and the value of V is obtained from

V = — + — - ^-+—
2.7 2.0 8.5 '

representing the differential volume affected by temperature and pressure and being
a constant for the tubes and in which

XXVIII] BAKING POWDERS 343

G = the weight of the empty tubes;

F = the weight of the fillings;
2.7 = the specific gravity of glass;
2.0 = the specific gravity of filling;
8.5 = the specific gravity of brass;

G F

— ■ + — - = volume of tubes and fillings;

2.7 2.0
G + F

volume of brass weights.

8.5

9 RESIDUAL CARBON DIOXID3.— TENTATIVE.

Weigh 2 grams of the baking powder into a flask suitable for the subsequent
determination of carbon dioxid, add 20 cc. of cold water and allow to stand 20 min-
utes. Place the flask in a metal drying cell surrounded by boiling water and heat,
with occasional shaking, for 20 minutes.

To complete the reaction and drive off the last traces of gas from the semi-solid
mass, heat quickly to boiling and boil for a minute. Aspirate until the air in the
flask is thoroughly changed, and determine the residual carbon dioxid by absorption,
as directed under 5 or 8.

The process described3, based on the methods of McGill4 and Catlin5, imitates
as far as practicable the conditions encountered in baking but in such a manner that
concordant results may be readily obtained on the same sample and comparable
results on different samples.

10 AVAILABLE CARBON DIOXID.— TENTATIVE.
Subtract the residual carbon dioxid from the total.

1 1 ACIDITY.-TENTATIVE.

(For cream of tartar and its substitutes.)

Dissolve 1 gram of the sample in hot water and titrate with N/5 potassium hy-
droxid, using phenolphthalein as an indicator.

TARTARIC ACID, FREE OR COMBINED.

1 2 Wolff Method6.— Tentative.
(Applicable in the presence of phosphates.)

Shake repeatedly about 5 grams of the sample with about 250 cc. of cold water
in a flask and allow the insoluble portion to subside. Decant the solution through
a filter and evaporate the filtrate to dryness. Powder the residue, add a few drops
of 1% resorcin solution and about 3 cc. of strong sulphuric acid and heat slowly.
Tartaric acid is indicated by a rose-red color which is discharged on dilution with
water.

TOTAL TARTARIC ACID.

1 3 Goldenberg-Geromont-Heidenhain Method. — Tentative.
(Applicable only in the absence of aluminium salts, calcium salts and phosphates.)

Into a shallow 6 inch porcelain dish weigh out 2 grams of the sample and suffi-
cient potassium carbonate to combine with all the tartaric acid not in the form of
potassium bitartrate. Mix thoroughly with 15 cc. of cold water and add 5 cc. of
99% acetic acid. Stir for 30 seconds with a glass rod bent near the end. Add 100
cc. of 95% alcohol, stir violently for 5 minutes, and allow to settle at least 30 min-

344 METHODS OF ANALYSIS [Chap.

utes. Filter on a Gooch crucible with a thin layer of paper pulp and wash with 95%
alcohol until 2 cc. of the filtrate do not change the color of litmus tincture diluted
with water. Place the precipitate in a small casserole, dissolve in 50 cc. of hot water
and add N/5 potassium hydroxid, leaving it still strongly acid. Boil for a minute.
Finish the titration, using phenolphthalein as an indicator and correct the reading
by adding 0.2 cc. One cc. of N/5 potassium hydroxid, under the above conditions,
is equivalent to 0.02541 gram of tartaric anhydrid, 0.03001 gram of tartaric acid,
or 0.03763 gram of potassium bitartrate. Standardize the N/5 potassium hydroxid
by means of pure potassium bitartrate.

The accuracy of this method is indicated by the agreement of the percentages of
potassium bitartrate in cream of tartar powders containing no free tartaric acid,
obtained by calculation from the tartaric acid, with those obtained by calculation
from the potassium oxid7.

FREE TARTARIC ACID.

14 Qualitative Test. — Tentative.

Extract 5 grams of the sample with absolute alcohol and evaporate the alcohol
from the extract. Dissolve the residue in dilute ammonium hydroxid, transfer to
a test tube, add a good sized crystal of silver nitrate and heat gently. Tartaric
acid is indicated by the formation of a silver mirror. If desired, the absolute alco-
hol extract may be tested as directed under 12.

15 Quantitative Method. — Tentative.

Calculate the percentage of tartaric anhydrid combined with the potash as bi-
tartrate, if any, and subtract this from the percentage of total tartaric anhydrid.
The difference is the tartaric anhydrid originally added as the free acid, although,
if the sample has been kept for a long time or has been improperly stored, a portion
or all of this acid may exist at the time of analysis as the sodium salt resulting from
the reaction in the can with the sodium bicarbonate. Multiply by 1.137 to obtain
the percentage of tartaric acid.

16 POTASSIUM BITARTRATE.— TENTATIVE.

If, as is usually the case, potassium bitartrate is the only potassium salt present,
multiply the percentage of total potash, determined as directed under 24, by 3.994.

STARCH.

1 7 Direct Inversion Method. — Tentative.

(For all baking powder ingredients free from lime.)

Weigh 5 grams of the powder into a 500 cc. graduated flask and proceed as directed
under VIII, 60.

1 8 Indirect Method9. — Tentative.

(For phosphate, alum phosphate and all other baking powders containing lime.)

Mix 5 grams of the powder with 200 cc. of 3% hydrochloric acid in a 500 cc. grad-
uated flask and allow the mixture to stand for an hour, with frequent shaking.
Filter on an 11 cm. hardened filter, taking care that a clear filtrate is obtained.
Rinse the flask once without attempting to remove all the starch, and wash the
paper twice with cold water. Carefully wash the starch from the paper back into
the flask with 200 cc. of water. Add 20 cc. of 25rc hydrochloric acid and proceed as
directed under VIII, 60.

XXVIII] BAKING POWDERS 345

The treatment with 3% hydrochloric acid, without dissolving the starch, removes
effectively the lime, which otherwise would be precipitated as tartrate by the
alkaline copper solution.

1 9 Modified McGill Method. — Tentative.

Digest 1 gram of the powder with 150 cc. of 3% hydrochloric acid for 24 hours
at room temperature, with occasional shaking. Filter on a Gooch crucible, wash
thoroughly with cold water and then once each, with alcohol and ether. Dry at
110°C. (4 hours is usually sufficient), cool and weigh. Burn off the starch, weigh
again and determine the starch by difference.

The results by this method on cream of tartar powders and tartaric acid pow-
ders agree closely with those obtained by copper reduction. On phosphate, alum
and alum-phosphate powders the results are usually satisfactory, but in some
instances they may be over 2% too high.

ALUM IN THE PRESENCE OF PHOSPHATES9.

20 Qualitative Test. — Tentative.

(a) In baking powder. — Burn about 2 grams of the sample to an ash in a porce-
lain dish. Extract with boiling water and filter. Add to the filtrate a few drops
of ammonium chlorid solution. A flocculent precipitate indicates alum.

(b) In cream of tartar. — Mix about 1 gram of the sample with an equal quantity
of sodium carbonate, burn to an ash and proceed as in (a).

Ash1".

21 insoluble ash and preparation of solution.-tentative.

Char 5 grams of the sample in a platinum dish at a heat below redness. Boil the
carbonaceous mass with dilute hydrochloric acid, filter into a 500 cc. graduated
flask and wash with hot water. Return the residue, together with the paper, to
the platinum dish and burn to a white ash. Boil again with hydrochloric acid,
filter, wash, unite the 2 filtrates and dilute to 500 cc.

Incinerate the residue after the last filtration and determine the ash insoluble
in acid.

22 IRON AND ALUMINIUM.— TENTATIVE.

Draw a 100 cc. aliquot of the solution, prepared as directed in 21, and separate
silica, if necessary. Mix the solution with sodium phosphate solution in excess.
Add ammonium hydroxid until a permanent precipitate is obtained, then hydro-
chloric acid, drop by drop, until the precipitate is dissolved. Heat the solution
to about 50°C, mix with a considerable excess of 50% ammonium acetate solution
and 4 cc. of 80% acetic acid.

As soon as the precipitate of aluminium phosphate, mixed with iron phosphate,
has settled, collect on a filter, wash with hot water, ignite and weigh.

Fuse the mixed phosphates with 10 parts of sodium carbonate, dissolve in dilute
sulphuric acid, reduce with zinc, and determine the iron by titration with a standard
permanganate solution. In the same solution determine the phosphoric acid, as
directed under I, 6 or 9. To obtain the weight of alumina (A1203) subtract the
sum of the weights of ferric oxid (Fe20a) and phosphorus pentoxid (PtOi) from the
weight of the mixed phosphates.

346 METHODS OF ANALYSIS [Chap.

23 CALCIUM.— TENTATIVE.

Heat the combined filtrate and washings, obtained in 22, to 50°C. and add an
excess of ammonium oxalate solution. Allow to stand in a warm place until the
precipitate has settled, filter, wash the precipitate with hot water, dry, ignite over
a Bunsen burner and finally over a blast lamp. Cool in a desiccator and weigh as
calcium oxid.

24 POTASSIUM AND SODIUM.— TENTATIVE.

Evaporate an aliquot of the solution, prepared as directed under 21, nearly
to dryness to remove the excess of hydrochloric acid, dilute and heat to boiling.
While still boiling add barium chlorid solution so long as a precipitate forms and
then enough barium hydroxid solution to make the liquid strongly alkaline. As
soon as the precipitate has settled, filter and wash with hot water, heat the filtrate
to boiling, add sufficient ammonium carbonate solution (1 part of ammonium car-
bonate in 5 of 2% ammonium hydroxid solution) to precipitate all the barium,
filter and wash with hot water. Evaporate the filtrate to dryness and ignite the
residue below redness to remove ammonium salts. Add to the residue a little
water and a few drops of ammonium carbonate solution. Filter into a tared plat-
inum dish, evaporate, ignite below redness and weigh the mixed potassium and
sodium chlorids.

Determine potassium in the mixed chlorids as directed in I, 45, beginning with
"Digest the residue with hot water, filter through a small filter". Calculate the
potassium so found to its equivalent of potassium chlorid and subtract this from
the weight of the mixed chlorids to obtain the weight of sodium chlorid.

25 PHOSPHORIC ACID.— OFFICIAL.

Mix 5 grams of the sample with a little magnesium nitrate solution, dry, ignite,
dissolve in dilute hydrochloric acid and dilute the solution to a definite volume.
In an aliquot of the solution determine phosphoric acid as directed under I, 6 or 9.

26 SULPHURIC ACID11.— TENTATIVE.

Boil 5 grams of the sample gently for 1| hours with a mixture of 300 cc. of water
and 15 cc. of concentrated hydrochloric acid. Dilute to 500 cc, draw off a 100 cc.
aliquot, dilute considerably, precipitate with 10% barium chlorid solution, filter
the precipitated barium sulphate on a Gooch, wash with hot water, dry, ignite and
weigh.

27 AMMONIA— TENTATIVE.

Introduce 2 grams of the sample into a distillation flask, add 300-400 cc. of water
and an excess of sodium hydroxid solution, connect with a condenser and distil into
a measured amount of standard acid. Titrate the excess of acid in the distillate
with standard alkali, using methyl red or cochineal as an indicator.

Ammonia alum is often an ingredient of cream of tartar substitutes and baking
powders, and ammonium carbonate is occasionally present in baking powders.

Method I. Colorimetric Method12. — Tentative.
(Applicable in the absence of alum and phosphates. Approximate method for

preliminary work.)

28 REAGENTS.

(a) Sodium bisulphite solution. — Dissolve 10 grams of anhydrous sodium car-
bonate in sufficient water to make 100 cc. and pass sulphur dioxid into the solution

XXVIII] BAKING POWDERS 347

until carbon dioxid is no longer evolved. Dilute a little of this solution with 10
volumes of water as needed in the determination.

(b) 10% potassium cyanid solution.

(C) Standard lead solution. — Dissolve 1.6 grams of crystallized lead nitrate, pre-
viously dried over sulphuric acid, in a liter of water containing a few drops of dilute
nitric acid. One cc. of this solution is equivalent to 1 mg. of metallic lead. Dilute

1 cc. of this solution to 100 cc. immediately before use in making up the color
standards.

(d) Lead-free tartrate solution. — Dissolve 200 grams of tartaric acid in about 500
cc. of hot water, cool, add 40 cc. of the sodium bisulphite solution, heat to incipient
boiling and test a few drops of the solution with potassium sulphocyanate solution
to ascertain if all the iron is reduced to the ferrous state, repeating the treatment
with about 10 cc. of the sodium bisulphite solution in case ferric iron is still present.
Cool, add 20 cc. of the 10% potassium cyanid solution, and then strong ammonium
hydroxid solution until the solution is distinctly alkaline to litmus paper. Boil
until the solution is clear, cool, add 2 cc. of freshly prepared, colorless ammonium
sulphid solution, dilute to 1 liter and allow to stand overnight. Filter to remove
the precipitated sulphids, boil the filtrate until hydrogen sulphid is removed, cool
and dilute to 1 liter with water.

29 PREPARATION OF SOLUTION.

(a) Baking powder. — Weigh 20 grams of the sample into a 250 cc. casserole, add
water a little at a time with stirring until foaming ceases, then hydrochloric acid
(1 to 1) a little at a time until all the carbonate is decomposed and finally 5 cc.
excess of the hydrochloric acid. Cover with a watch glass and digest on a steam
bath until all the starch is hydrolyzed as shown by testing 1 or 2 drops of the mix-
ture with iodin. Filter through a folded filter and wash the filter several times with
small portions of hot water. Treat the residue on the filter with several small por-
tions of hot nitric acid (sp. gr. 1.2), collect the acid solution in a separate, small
porcelain dish, evaporate this solution to dryness on a water bath and expel nitric
acid by several treatments and evaporations with a few drops of concentrated
hydrochloric acid. Rinse the contents of the dish through a small filter into the
main solution and make up to 100 cc.

(b) Tartaric acid and cream of tartar. — Dissolve 100 grams of the sample in hot
water, add 50 cc. of hydrochloric acid (1 to 1), filter into a liter graduated flask,
wash the filter several times with water, and then treat the residue on the filter
with several small portions of hot nitric acid (sp. gr. 1.2), collect the acid solution
in a separate, small porcelain dish, evaporate this solution to dryness on a water
bath and expel nitric acid by several treatments and evaporations with a few drops
of concentrated hydrochloric acid. Rinse the contents of the dish through a
small filter into the main solution, finally diluting the combined filtrates and wash-
ings to a liter.

30 DETERMINATION.

Introduce 50 cc. of the solution, prepared as directed in 29. into a beaker, add

2 cc. of the sodium bisulphite solution, heat to incipienl boiling, and lest a few
drops of the solution with potassium sulphocyanate to determine if all the iron is
reduced to the ferrous state, repeating the treatment with the sodium bisulphite
solution if ferric iron is still present. Cool, add 1 cc. of the 10% potassium cyanid
solution and neutralize to litmus with strong ammonium hydroxid solution; finally
add an excess of 1 cc. of the last reagent. Boil gently until clear and colorless, cool

348 METHODS OF ANALYSIS [Chap.

and make up to 100 cc. Treat with 2 drops of freshly prepared, colorless ammo-
nium sulphid solution, mix and compare in a colorimeter with standard solutions,
prepared by adding measured amounts of the standard lead solution to 50 cc. of
the lead-free tartrate solution, diluting to 100 cc. and treating with 2 drops of
freshly prepared colorless ammonium sulphid solution.

The final comparison should be made with a standard containing approximately
the same amount of lead, and the addition of ammonium sulphid solution should be
made to the standards and the solution of the sample at the same time, as the colors
change on standing.

31 Method II. — Tentative.

(Applicable to alum or phosphate baking powders or their ingredients.)

Weigh 100 grams of the sample into a 1.3 liter beaker and add an excess of hy-
drochloric acid (1 to 3) in small portions, keeping down excessive frothing with a
little ether. Heat the mixture on a steam bath until the starch is hydrolyzed and
the solution is quite limpid. Cool and add 200 cc. of 50% lead-free ammonium
citrate solution. Place the beaker in a bath of cold water and add carefully ammo-
nium hydroxid solution, in small portions with constant stirring, until the mixture
is alkaline. If a precipitate forms, add sufficient ammonium citrate solution to
dissolve it. Then add 15 cc. of saturated mercuric chlorid solution, dilute the
mixture to about 1200 cc, saturate with hydrogen sulphid and allow to stand
until the precipitate has settled (15-20 minutes). Filter and wash the precipitate
with hydrogen sulphid water. Place the paper and precipitate in a small casserole,
add 10 cc. of concentrated nitric acid and 2 cc. of concentrated sulphuric acid and
heat on a hot plate until the mixed acids have been slowly driven off. Heat the
residue in a muffle at low redness until the mercury salts have volatilized. Cool
the casserole and leach the residue several times with 25% ammonium acetate solu-
tion, made slightly alkaline with ammonium hydroxid, pass the teachings through
a small filter into a beaker and finally wash the residue and filter paper with a
little hot water. Acidify the combined filtrate and washings with acetic acid, add
an excess of potassium dichromate solution and allow to stand overnight. Filter
on a tared Gooch, wash with water, dry for 30 minutes at 125°-150°C, cool and
weigh as lead chromate. Calculate the weight of metallic lead. Conduct a blank
determination upon all the reagents and correct the result accordingly.

32 Method III.— Tentative.

(Applicable to alum or phosphate baking powders or their ingredients.)

Transfer 200 grams of the sample to a 3 liter Jena flask, add 300 cc. of concen-
trated nitric acid in small portions, shake thoroughly after each addition and
heat the mixture slowly, shaking repeatedly. When brown fumes begin to appear
at the mouth of the flask, discontinue heating and insert a stemless funnel in the
neck of the flask. As soon as the action has moderated, place the flask on an
asbestos gauze over a small Bunsen flame. When the action becomes weak, add
slowly 90 cc. of concentrated sulphuric acid and continue heating until the fumes
disappear. Then add 25 cc. of concentrated nitric acid from time to time with con-
tinued heating until all the starch is completely oxidized. Usually 3-4 additions
of 25 cc. portions of nitric acid suffice. Finally expel the nitric acid as completely
as possible. Cool, add 400 cc. of water, .shake and allow to settle. The soluble sul-
phates of sodium, potassium, aluminium, iron, etc., go into solution, while calcium
sulphate and most of the lead sulphate will be precipitated. Filter through an 18

XXVIII] BAKING POWDERS 349

cm. folded filter into a liter Erlenmeyer flask, rinse the 3 liter flask 2-3 times with
small portions of water and pour the rinsings through the filter. Reserve the fil-
trate for the recovery of dissolved lead salts. Open the filter, containing the pre-
cipitate, over a 600 cc. beaker and wash the precipitate into it. Then transfer the
contents of the beaker to a 2 liter Erlenmeyer flask together with whatever pre-
cipitate remains in the 3 liter flask. Dilute the contents of the flask so as to nearly
fill the latter, stir thoroughly to dissolve the calcium sulphate, add 20 cc. of strong
acetic acid and saturate the liquid thoroughly with hydrogen sulphid. Stopper
the flask and set aside until the precipitate settles. Siphon off the supernatant
liquid. When much calcium sulphate is present, one such treatment is not suffi-
cient to dissolve all of it. In this case refill the flask with water, again acidify,
saturate with hydrogen sulphid and allow to stand till the calcium sulphate is
practically all dissolved and the residue of sulphids is dark colored. Solution may
be hastened by the addition of lead-free sodium acetate to the water (50-75 grams
to each 2 liters).

Treat the liquid containing the soluble sulphates separately to recover the trace
of lead which it may contain. Partially neutralize with ammonium hydroxid solu-
tion just short of the point of producing a permanent precipitate of aluminium
phosphate, saturate with hydrogen sulphid and allow the precipitate to settle.
Some iron sulphid also will usually be precipitated. The sulphid precipitations
should be made in very slightly acid solutions, otherwise lead sulphid will not be
precipitated completely. Siphon off the supernatant liquid, transfer the precipi-
tate to an 11 cm. filter and wash with hydrogen sulphid water. Transfer the first
precipitate remaining in the 2 liter flask to a second 11 cm. filter and treat in the
same way. Place the 2 filters with their contents in a 200 cc. Erlenmeyer flask,
add 10 cc. of concentrated nitric acid and 5 cc. of concentrated sulphuric acid,
insert a stemless funnel in the neck and heat to completely oxidize the material.
When the nitric acid has all been expelled and the residue darkens, add more nitric
acid until no such darkening occurs. Finally heat the residuevtill fumes of sulphur
trioxid are given off, cool and add 15 cc. of water. Filter through a 7 cm. filter,
rinse, then wash the filter twice with small portions of dilute sulphuric acid and
finally with a little water. Place a clean 150 cc. beaker under the filter, dissolve
the precipitate in 15-25 cc. of ammonium acetate solution [1 part of 99% acetic
acid, 1 of water and 1 of ammonium hydroxid (sp. gr. 0.90); made neutral to lit-
mus paper] and wash thoroughly with water.

Acidify the filtrate and washings with acetic acid, add an excess of potassium
dichromate solution, heat on a steam bath and allow to cool and settle. Filter on
a tared Gooch prepared with a thick layer of asbestos which has been previously
dried at 125°C, wash with water, dry at about 125°C. and weigh as lead chromate

33 Method IV. — Tentative.

(Applicable in the absence of alum and phosphates.)

Weigh 100 grams of the sample into a liter beaker and add an excess of hydro-
chloric acid (1 to 3) in small portions, keeping down excessive frothing with a little
ether. Heat the mixture on a steam bath until the starch is hydrolyzed and the
solution is quite limpid. Cool, add ammonium hydroxid solution until distinctly
alkaline, dilute to about 800-900 cc. and sat unite with hydrogen sulphid. Allow
the mixture to stand for 3-4 hours or until the precipitate has settled, filter on a
12.5 cm. close-textured paper and wash the precipitate several times with hydrogen
sulphid water. Place the filter paper and precipitate in a 1D0 cc. Erlenmeyer Bask,
add 5 cc. of concentrated sulphuric acid and 5 cc. of concentrated nitric acid and

METHODS OF ANALYSIS

heat on a hot plate, with occasional additions of small portions of concentrated
nitric acid, until the mixture no longer blackens when evaporated to the point at
which white fumes of sulphur trioxid appear. Cool, dilute with 20 cc. of water,
warm until the ferric sulphate goes into solution, cool and then add 40 cc. of 95%
alcohol by volume. Allow to stand overnight, filter on a Gooch and wash with
95% alcohol. Dissolve the lead sulphate remaining on the filter by washing with
20 cc. of 25% ammonium acetate solution, rendered slightly alkaline with ammo-
nium hydroxid, collect the filtrate in a small beaker, passing it through the filter
3-4 times. Finally wash the filter with hot water, acidify the combined filtrate
and washings with acetic acid, add an excess of potassium dichromate solution and
allow to stand overnight. Filter on a small, tared Gooch, wash, dry for 30 minutes
at 125°-150°C. and weigh as lead chromate. Calculate the metallic lead.

34 ARSENIC— TENTATIVE.

Introduce 5 grams of the sample directly into the generator described under
XII, 2 (Fig. 7), add 10 cc. of water, a little at a time to prevent foaming over,
and then 15 cc. of concentrated, arsenic-free hydrochloric acid, introducing it drop
by drop until foaming ceases. Heat on a steam bath until a drop of the mixture,
when diluted and treated with iodin solution, shows no blue color. Then dilute to
about 30 cc. with water, add 4 cc. of potassium iodid solution and continue from
this point as directed under XII, 4, beginning with "Heat to about 90°C", except
that the blank and the standards for comparison are made by the use of the arsenic-
free hydrochloric acid of the same concentration as that used in the determination.

BIBLIOGRAPHY.

1 J. Am. Chem. Soc, 1899, 21: 396.

2 Ibid., 1896, 18: 1.

3 Conn. Agr. Exp. Sta. Rept., 1900, (II), p. 169.

4 Inland Revenue Dept., Canada, Bull. 68, p. 31.

5 Catlin. Baking Powders: A Treatise on Their Character, Method for Deter-
mination of Their Values, etc. p. 20.

6 Ann. chim. anal., 1899, 4: 263.

7 Conn. Agr. Exp. Sta. Rept., 1900, (II), p. 180.

8 Ibid., p. 174.

9 Rept. Mass. State Board of Health, 1899, p. 638.

10 Conn. Agr. Exp. Sta. Rept., 1900, (II), p. 178.

11 U. S. Bur. Chem. Bull. 13 (V), p. 596; Conn. Agr. Exp. Sta. Rept., 1900, (II),
p. 179.

12 J. Assoc. Official Agr. Chemists, 1915, 1: 249.

XXIX. DRUGS.

Caffein and Acetanilid in Mixtures.

1 preparation of sample and solution.— tentative.

(a) If the sample is already in powder form, rub thoroughly in a mortar and
keep in a tightly corked tube or flask. Powders in paper, cachet or capsule con-
tainers are frequently of such fineness as to require little further trituration except
to produce a uniform product. On a tared 5.5 cm. filter weigh 0.3-0.5 gram of the
sample or, if preferred, an amount equal to, or a multiple of, the average unit dose
(previously ascertained by weighing collectively 20 or more such doses), wash with
successive 5-10 cc. portions of the chloroform (30-50 cc. are usually sufficient) until
the extraction is complete as indicated by the absence of any residue after evapora-
tion of a small portion of the last washing. Collect the solution in a 200 cc. Erlen-
meyer flask, connect the flask with a condenser by means of a cylindrical Kjeldahl
connecting bulb1 and distil until the volume is reduced to about 10 cc.

(b) If the caffein is present in the citrated form, or the composition of the mix-
ture precludes complete extraction as directed in (a), weigh out the desired amount,
transfer to a Squibb separatory funnel, add 50 cc. of the chloroform and 20 cc. of
water, shake vigorously and, after clearing, draw off the lower layer through a
small, dry filter into a 200 cc. Erlenmeyer flask. In the case of coated tablets and
pills, ascertain their average weight, powder in a mortar and weigh out for each
determination an amount equivalent to one or more tablets or pills. Repeat the
extraction twice, using 50 cc. portions of the chloroform for each extraction. Dis-
til the combined chloroform extracts to about 10 cc.

(C) In the case of dilute alcoholic solutions, evaporate a measured quantity on
a steam bath until most of the alcohol has been expelled, or take an aliquot of
the residue from an alcohol determination; transfer to a separatory funnel by pour-
ing and rinsing with a minimum of water so that the final volume does not greatly
exceed 20 cc, and then, in order to avoid any loss of acetanilid by hydrolysis during
evaporation, add a little solid sodium bicarbonate and a drop of acetic anhydrid.
(Should the preparation contain alkaloids, acidify with a few drops of dilute sul-
phuric acid immediately after acetylization to retain such basic material in solu-
tion.) Add 50 cc. of the chloroform, shake vigorously and, after clearing, draw off
the chloroform layer through a filter into a 200 cc. Erlenmeyer flask. Repeal the
extraction twice, using 50 cc. portions of the chloroform for each extraction, and
distil the combined chloroform washings to a volume of about 10 cc.

CAFFEIN AND ACETANILID.— TENTATIVE.

2 REAGENTS.

(a) Standard bromid-bromate .solution. — Dissolve 50 grams of potassium hvdroxid
in a small quantity of water, add a slight excess of bromin, dilute with water to dis-
solve any separated salts, boil to expel excess of bromin and dilute to 1 liter. Stand-
ardize the solution against recrystallized acetanilid and adjust t he solution so that
1 cc. is equivalent to 5 or 10 mg. of acetanilid as desired.

(b) Chloroform. — Redistilled and residue-free. All corks used in t he dist illat ion
should be treated previously with chloroform.

351

352 METHODS OF ANALYSIS [Chap.

(C) Wagner's reagent. — Dissolve 2 grams of iodin and 6 of potassium iodid in a
minimum amount of water and dilute to 100 cc.

3 CAFFEIN.— TENTATIVE.

Treat the chloroform extract, obtained in 1, with 10 cc. of sulphuric acid (1 to
10) and digest on a steam bath until the contents of the flask are reduced to 5 cc.
Add 10 cc. of water and continue the digestion until the liquid is again reduced to
5 cc, then cool and transfer to a separatory funnel with a minimum of water, so
that the final volume does not greatly exceed 20 cc. Add 50 cc. of the chloroform,
extract in the usual way and, after clearing, withdraw the lower layer through a
small, dry filter into a 200 cc. Erlenmeyer flask. Repeat the extraction with two
50 cc. portions of the chloroform. On the completion of the third extraction,
distil the combined extracts down to about 10 cc, finally transferring the residual
liquid, by washing with chloroform, to a tared beaker or crystallizing dish. Allow
the solution to evaporate spontaneously, or by gentle heat and an air blast, to
apparent dryness. Cool and allow to stand until the weight becomes constant.

Chloroform extracts in addition to caffein and acetanilid certain oils, fats, waxes,
resins, pigments and other substances from those preparations which contain pow-
dered cinnamon, celery seed, ginger or other vegetable products. These appear either
in suspension or solution after the caffein-acetanilid mixture has been digested and
contaminate the caffein. Remove any suspended impurities by filtering through
a small, moistened filter immediately after hydrolysis and prior to extraction with
chloroform. Should the recovered caffein be deeply colored or contaminated with
foreign matter, purify it as follows: Dissolve in very dilute sulphuric acid (about
5 cc of N/5 acid for everjr 100 mg. of caffein), filter, if necessary, through a mois-
tened filter, add 15-20 cc. of Wagner's reagent, sufficient at least to distinctly color
the supernatant liquid, stir and allow to stand an hour, preferably in a refrigerator.
Filter and wash the periodic! with a few cc. of iodin solution, transfer both filter and
precipitate to a separatory funnel, using not more than 20 cc. of water, decolorize
with a crystal of sodium thiosulphate, then extract with three 50 cc. portions of
chloroform and proceed as directed above.

4 ACETANILID.-TENTATIVE.

Transfer the solution of anilin sulphate, remaining in the separatory funnel
in 3, to the Erlenmeyer flask used in effecting hydrolysis, then heat 10 minutes on
a steam bath to expel all traces of chloroform. Wash the filter, used in the pre-
ceding operation to dry the chloroform solution of caffein, with 5 cc. of water,
adding the latter to the main solution of anilin sulphate. Add 10 cc. of concen-
trated hydrochloric acid, then run in the standard bromid-bromate solution until
a faint yellow coloration remains, rotating the flask sufficiently to agglomerate the
precipitated tribromanilin. Calculate the quantity of acetanilid from the number
of cc. required to complete the precipitation.

Caffein and acetanilid are the 2 principal ingredients of the preparation known
as "acetanilid compound", a further constituent being sodium bicarbonate. The
latter appears as the chloroform-insoluble residue and may be determined by ti-
trating such residue, or one obtained by titrating a portion of the original mixture,
with standard acid, using congo red as an indicator. The bicarbonate may also
be determined by igniting the original sample, or the chloroform-insoluble residue,
with sulphuric acid and weighing the resulting sodium sulphate.

Should the "acetanilid compound" be combined with sodium bromid, the latter,
in the absence of other halides, may be determined volumetrically by the Volhard
method [III, 15].

XXIX] drugs 353

Caffein and Acetphenetidin (Phenacetin) in Mditures.

5 preparation of sample and solution.— tentative.

In the case of preparations containing acetphenetidin instead of acetanilid, but
otherwise identical, make the gross separation of the caffein-acetphenetidin mix-
ture as directed under 1 .

6 CAFFEIN.— TENTATIVE.

Treat the chloroform extract, obtained as directed under 1, with 10 cc. of sul-
phuric acid (1 to 10) and digest on a steam bath until the liquid is reduced to about
5 cc. Dilute with 10 cc. of water and continue the digestion until the volume is
again reduced to 5 cc, then add 10 cc. of water and continue heating until the
residual liquid amounts to 8-10 cc. If, during the digestion, particles of acet-
phenetidin remain on the sides of the flask rinse them into the solution with a few
drops of chloroform.

Great care must also be given to the degree of evaporation. Should the aqueous-
acid solution and suspension of caffein-acetphenetidin be concentrated far beyond
the limits indicated, more or less phenetidin sulphonate is likely to be formed,
which later resists acetylization and conversion to acetphenetidin.

Cool and transfer with water to a separatory funnel, so that the final volume does
not greatly exceed 20 cc. Then proceed as directed under 3.

7 ACETPHENETIDIN.— TENTATIVE.

Wash the filter, used to dry the chloroform in 6, with 5 cc. of water, receiving the
latter in the separatory funnel containing the solution of phenetidin sulphate.
Treat with successive small portions of solid sodium bicarbonate until, after com-
plete neutralization of free acid, an excess of the former remains at the bottom of the
mixture. Add 50 cc. of chloroform and for every 0.10 gram of acetphenetidin, known
or believed to have been present, 5 drops of acetic anhydrid; shake vigorously, allow
to clear, then withdraw the chloroform into a second separatory funnel containing
5 cc. of water. Shake this mixture and, after clearing, pass the solvent through a
small, dry filter into a 200 cc. Erlenmeyer flask. Distil over about 40 cc. of the
chloroform, make up the distillate to 50 cc. with chloroform, add this to the mate-
rial in the first separatory funnel and extract again. Withdraw the chloroform
layer to the second separatory funnel, wash and distil about 50 cc.(for use in the
final extraction). Distil the chloroform down to about 10 cc, transfer with sufficient
fresh solvent to a tared 50 cc. beaker or crj-stallizing dish, evaporate on the steam
bath to apparent dryness, finally removing any considerable excess of acetic anhy-
drid by repeated additions of 1 cc. of chloroform and a drop of alcohol. The re-
formed acetphenetidin should finally appear as a whitish, crystalline mass with
a faint, acetous odor which disappears completely on standing some hours in the
open, or in a vacuum desiccator over lime. Weigh from time to time until the
final weight differs from the preceding by not more than 0.5 mg.

Caffein and Antipyrin in Mixtures2.

8 preparation of sample and solurion.-tentative.

(a) Extract a weighed portion of the finely powdered sample on a filter with
chloroform to separate the caffein and antipyrin from the usual excipients of tali-
let and pill combinations. Distil off the greater part of the chloroform ami evap-
orate the remainder on the steam bath.

354 METHODS OF ANALYSIS [Chap.

(b) In the case of alcoholic preparations, remove the alcohol from a measured
amount of the sample by heating on a steam bath. Extract the residue with three
50 cc. portions of chloroform in a separatory funnel. Distil off the greater por-
tion of the chloroform and evaporate the remainder on a steam bath.

9 ANTIPYRIN.— TENTATIVE.

Transfer the residue, obtained in 8, which should weigh about 0.25 gram, to a
150 cc. separatory funnel by means of two 5 cc. portions of alcohol-free chloroform,
followed by 10 cc. of water. Add 1 gram of sodium bicarbonate and 10-15 cc. of
N/5 iodin (or double the quantity of N/10 iodin), adding the latter in small por-
tions and shaking the mixture vigorously after each addition. The iodin should
then be in excess of that required to convert all the antipyrin into the mono-iod
derivative. If not, add a little more and shake the mixture again. Remove the
free iodin with a small crystal of sodium thiosulphate, add 15 cc. of chloroform,
shaking vigorously for 1 minute. After clearing, draw off the chloroform solution
into a second separatory funnel, wash with 5 cc. of water, filter through a small,
dry filter into a tared 50 cc. beaker and evaporate to apparent dryness on the steam
bath, using an air blast. Repeat the extraction with two (three, if N/10 iodin is
used) 25 cc. portions of chloroform, wash, filter and evaporate each portion as
above. Dry the nearly colorless, crystalline residue of caffein and iodantipyrin 30
minutes at 105°C, cool and weigh. Designate this weight as "a".

Dissolve the composite residue in 5 cc. of glacial acetic acid, add 10 cc. of
saturated sulphur dioxid solution, then transfer with hot water to a 400-500
cc. beaker until the final volume amounts to about 200 cc. Add sufficient silver
nitrate solution to precipitate all the iodin (about 0.3 gram of silver nitrate); then
a few drops of nitric acid, heat nearly to boiling and stir to agglomerate the silver
iodid. Add 15 cc. of concentrated nitric acid, cover the beaker with a watch glass
and boil gently for 5 minutes. Filter by decantation through a tared Gooch, wash
the precipitate once with a little alcohol, then with two 100 cc. portions of boiling
water and finally transfer the iodid to the crucible. Wash several times with hot
water and again with alcohol to remove traces of organic matter, dry 30 minutes
in an air bath at 110CC, cool and weigh. The weight of silver iodid multiplied by
0.8012 gives the weight of antipyrin.

I 0 CAFFEIN.— TENTATIVE.

Calculate the quantity of caffein by multiplying the weight of silver iodid by
1.3374 and subtracting the product from the weight "a" above.

In the analysis of a mixture containing caffein, antipyrin, acetanilid and sodium
salicylate, the following steps are essential in effecting a separation: (I) Extraction
of caffein, acetanilid and antipyrin with chloroform from the aqueous soda solution;
(2) Hydrolysis with sulphuric acid of the 3 substances thus separated preliminary
to the determination of caffein and antipyrin as directed in 9 and 10.

Acetanilid and Acetphenetidin (Phenacetinj in Mixtures3,
acetphenetidin — tentative.

II REAGENTS.

(a) Purified iodin. — Dissolve 2 parts of resublimed iodin and 1 of potassium iodid
in 1 of water, pour the clear solution into a large volume of water. Biter and wash
the finely precipitated iodin several times on a porous plate with water. Dry in
the air and finally in a desiccator over sulphuric acid where it is kept in a glass-
stoppered weighing bottle.

XXIX] drugs 355

(b) Standard sodium thiosulphate solution. — Dissolve 30 grams of crystallized
sodium thiosulphate in water and dilute to 1 liter. Standardize this solution against
the purified iodin as follows: Weigh out about 0.3 gram of the purified iodin in a
small, glass capsule (about \ inch high and f inch diameter), provided with a closely
fitting glass cap or stopper, and place the capsule in a 200 cc. Erlenmeyer flask con-
taining 0.5 gram of potassium iodid dissolved in 10 cc. of water. After complete
solution, titrate with the sodium thiosulphate solution, using 1 or 2 drops of starch
solution as an indicator.

(C) Standard iodin solution. — Dissolve 40 grams of potassium iodid in the least
possible quantity of water, add 30 grams of the purified iodin and, after solution,
dilute to 1 liter. Standardize 25 cc. of this solution against the standard sodium
thiosulphate solution.

12 DETERMINATION.

(1) Place 0.2 gram of the acetphenetidin-acetanilid mixture in a 50 cc. lipped
Erlenmeyer flask, add 2 cc. of glacial acetic acid, heat gently over a wire gauze to
complete solution and dilute with 40 cc. of water, previously warmed to 70°C.
Transfer the clear liquid with two 10 cc. portions of warm (40°C.) water to a glass-
stoppered, 100 cc. graduated flask containing 25 cc. of the standard iodin solution
warmed to 40°C. Stopper, mix thoroughly, then add 3 cc. of concentrated hydro-
chloric acid, continue shaking until crystallization begins and then set aside to
cool. If the ratio of acetphenetidin to acetanilid is equal to or greater than unity,
crystalline scales will form almost immediately on the addition of acid. As the
proportion of acetanilid increases, however, the periodid tends to remain in the liquid
state. In such cases, gentle agitation or rotation of the flask in water, warmed
not to exceed 40°C, hastens the formation of crystals. When the contents of the
flask are at room temperature, fill with water to within 2-3 cc. of the mark, mix
thoroughly and allow to stand overnight. Fill to the mark with water, i six thor-
oughly, allow to stand 30 minutes, filter through a 5.5 cm. dry, closely fitted filter
into a 50 cc. graduated flask, rejecting, however, about 15 cc. of the first runnings
but reserving them for the recovery of acetanilid. Transfer the 50 cc. aliquot to a
200 cc. Erlenmeyer flask and titrate with the standard sodium thiosulphate solution.
Calculate the amount of acetphenetidin from the following formula:

Acetphenetidin = I (0.0896 X N) in which

0.0896 = the quantity of acetphenetidin contained in 1 cc. of a normal
solution of this substance;
N = the normality of the standard sodium thiosulphate solution

employed ; and
I = the number of cc. of the standard sodium thiosulphate solu-
tion corresponding to the iodin combined with :
phenetidin.

The formula of the precipitated periodid, which constitutes tin' basis for the .
d< termination, is (C2H6O.Cc.H ;M I C< U 110 TIT. U

(2) The gravimetric determination of acetphenetidin may. if

as follows: Filter off the periodid, preferably by suction, wash v. ith
standard iodin solution, then ti tgether with the filter to a separa

using not over 50 cc. of water. Remove both id iodin with a few

crystals of sodium sulphite and extract the liquid with three 50 cc. portions of
chloroform, washing ei tch portion subsequently into a I with

5 cc. of water. After washing and cleari r the chloroform solution through

356 METHODS OF ANALYSIS [Chap.

a dry 5.5 cm. filter into a 200 cc. Erlenmeyer flask, distil off most of the chloro-
form, transfer the residual solution (5-10 cc), by means of a little chloroform, to
a small, tared beaker or crystallizing dish, evaporate to dryness on a steam bath,
cool and weigh.

For the identification of acetphenetidin, either alone or in admixture with acet-
anilid, the following test will be found of value3: To 1-2 mg. of the sample in a test
tube add a drop of acetic acid, 0.5 cc. of water and 1 cc. of N/10 iodin, warm the
mixture to about 40°C, then add a drop of concentrated hydrochloric acid. If
acetphenetidin alone is present, its periodid separates almost immediately in the
form of reddish brown leaflets or needle-like crystals. If the sample consists largely
of acetanilid, the separation takes place on cooling and shaking the liquid. In the
presence of considerable acetanilid, the periodid first separates as minute, oily
globules, which, on vigorous shaking, gradually become crystalline. This test is so
delicate that as little as 0.5 mg. of acetphenetidin may, if* alone, be detected in
the form of its characteristic periodid.

1 3 ACETANILID.-TENTATTVE.

(1) If the combined weight of the acetphenetidin-acetanilid mixture is known,
determine that of the latter ingredient by difference; or, (2) Determine it directly
from a second aliquot of the filtrate from the acetphenetidin periodid in 12 as follows:

Pipette 25-30 cc. of the clear liquid into a separatory funnel, decolorize with
solid sodium sulphite and solid sodium bicarbonate in slight excess, add 1 or 2 drops
of acetic anhydrid, then extract with three 60 cc. portions of chloroform, passing
the chloroform solution, when cleared, through a small, dry filter into a 200 cc.
Erlenmeyer flask, and distil the chloroform, by the aid of gentle heat, to about 20
cc. Add 10 cc. of sulphuric acid (1 to 10) and digest on a steam bath until the resi-
due has been reduced one half, add 20 cc. of water and continue the digestion for
an hour; then add a second 20 cc. portion of water and 10 cc. of concentrated hydro-
chloric acid, titrate very slowly, drop by drop, with the standard bromid-bromate solu-
tion, 2 (a), until a faint yellow color remains. While adding this reagent, rotate
the flask sufficiently to agglomerate the precipitated tribromanilin. Calculate the
amount of acetanilid present.

If the preparation contains caffein or antipyrin or both in addition to acet-
anilid and acetphenetidin, proceed as follows: (1) Digest the mixture by heating
with dilute sulphuric acid to convert acetphenetidin and acetanilid to phenetidin
and anilin sulphates, respectively; (2) Separate the caffein and antipyrin by ex-
traction with chloroform; (3) Re-form acetphenetidin and acetanilid by treat-
ing the solution of the corresponding sulphates with solid sodium bicarbonate in
slight excess, then add a few drops of acetic anhydrid and extract with chloroform*.

Acetphenetidin CPhenacetin) and Salol in Mixtures5,
acetphenetidin.

14 Acid Hydrolysis Method. — Tentative.

Weigh out on a tared 5.5 cm. filter an amount of the sample equal to, or a mul-
tiple of, the average weight of a unit dose and wash with sufficient successive, small
portions of chloroform to extract completely all acetphenetidin and salol present
in the mixture (about 40 cc). Collect the solution in a tared, 100 cc. beaker and
evaporate on a warm plate (50°-60°C.) to apparent dryness, using an air blast.
Let stand 24 hours at room temperature to practically constant weight, then trans-
fer the crystalline residue, by means of chloroform, to a 50 cc. lipped Erlenmeyer
flask, evaporate the solvent by means of an air blast and gentle heat, add 10 cc.

XXIX] drugs 357

of sulphuric acid (1 to 10) and evaporate on the steam bath until the volume is re-
duced one half. Add 10 cc. of water and continue the digestion as before, then add
a second 10 cc. of water and evaporate to 5 cc. Transfer the residue with about
20 cc. of water to a small separatory funnel and extract with 15, 10 and 5 cc. of
chloroform, washing each extract with 5 cc. of water in a second separatory funnel
to recover traces of phenetidin sulphate possibly dissolved by the chloroform,
finally rejecting the latter since it contains all the salol not previously eliminated
during the digestion.

Add the wash water in the second separatory funnel to the solution of phenetidin
sulphate in the first separatory funnel and proceed as directed under 7, beginning
with "Treat with successive small portions of solid sodium bicarbonate".

15 Alkaline Hydrolysis Method. — Tentative.

On a small, tared filter weigh out an amount of the sample to contain not more
than 0.10 gram of salol, exhaust with chloroform as directed in 14, collect the sol-
vent in a small, lipped Erlenmeyer flask and evaporate the chloroform by means of
an air blast without heat. Add 10 cc. of 2.5% sodium hydroxid solution and heat 5
minutes on a steam bath. Cool quickly to room temperature in running water to
prevent partial hydrolysis of the acetphenetidin. Transfer the liquid to a separa-
tory funnel with a minimum of water, then rinse out the flask with the first 20 cc.
portion of chloroform used in the extraction. Extract the alkaline solution with
three 20 cc. portions of chloroform, wash each portion in a second separatory funnel
with 5 cc. of water and pass the solution through a small, dry filter into a 200 cc.
Erlenmeyer flask. Designate the combined alkaline solution and washings as A.
Distil the combined chloroform extracts to about 5 cc. Transfer by means of a
little chloroform to a small, tared beaker or crystallizing dish, evaporate on a steam
bath with the aid of an air blast, cool and weigh the residual acetphenetidin at
intervals until the weight becomes constant.

SALOL.

16 Acid Hydrolysis Method. — Tentative.

Subtract the weight of acetphenetidin, as determined in 14, from the combined
weight of the 2 ingredients determined in 14, to obtain the weight of salol.

17 Alkaline Hydrolysis Method — Tentative.

Place the combined alkaline solutions, A, under 15, in a 500 cc. glass-stoppered
bottle, dilute with water to about 200 cc, run in from a burette an excess (about
45 cc.) of N/7 potassium bromid-bromate, add 10 cc. of concentrated hydrochloric
acid and shake 1 minute, then at intervals for 30 minutes. Add 10 cc. of 15% potas-
sium iodid solution and shake at intervals for 15 minutes. Titrate the free iodin
with standard sodium thiosulphate solution (preferably N/7), previously standard-
ized against the N/7 bromid-bromate solution. One cc. of N/7 potassium bromid-
bromate is equivalent to 2.55 mg. of salol. From the number of cc. of the N/7
bromid-bromate solution used, calculate the amount of .salol on the basis of 12 atoms
of bromin to 1 molecule of salol.

ACETANILID AND SODIUM SALICYLATE IN MIXTURES.

18 PREPARATION OF SAMPLE AND SOLUTION. -TENTATIVE.

Weigh an amount of the powdered sample equal to, or a multiple of. an average
unit dose, transfer to a separatory funnel containing 10 cc. of water and, for every
unit dose, add 0.10 gram of solid sodium bicarbonate. In the ease of coated tablets

358 METHODS OF ANALYSIS [Chap.

and pills, ascertain their average weight, powder in a mortar and weigh out an
amount of the powder equivalent to one or more tablets or pills for each determina-
tion prior to treatment in the separatory funnel. In the examination of alcoholic
preparations, distil off the alcohol from a measured volume on a steam bath,
transfer to a separatory funnel with a minimum of water and add sufficient solid
sodium bicarbonate (0.5 to 1.0 gram).

19 ACETANILID.— TENTATIVE.

Extract the alkaline solution, obtained under 18, with three 50 cc. portions of
chloroform, wash each portion with 5 cc. of water in a second separatory funnel
and collect the solvent, without previous drying, in a 200 cc. Erlenmeyer flask.
Designate the aqueous solution as A. Distil off the chloroform very gently to
about 5 cc, add 10 cc. of dilute sulphuric acid and completely hydrolyze on the
steam bath. Proceed from this point as directed in 4.

20 SODIUM SALICYLATE.-TENTATIVE.

Acidify the aqueous solution of sodium salicylate, A, under 19, with a few drops
of concentrated hydrochloric acid and extract with sufficient (3-5) 25 cc. portions
of chloroform to exhaust the salicylic acid present in the mixture. Treat each por-
tion in a second separatory funnel with 20 cc. of water, containing 1 gram of
anhydrous sodium carbonate for every 100 mg. of salicylic acid. Shake vigorousl}'
and, after clearing, wash each portion again in a second separatory funnel with 5 cc.
of water, then add the washings to the main aqueous soda solution of sodium
salicylate. Dilute to a known volume, transfer an aliquot, representing about 100
mg. of salicylic acid, to a 200 cc. Erlenmeyer flask, make up to 100 cc, heat nearly
to boiling, then run in from a burette 25-40 cc. of strong (about N/5) iodin solu-
tion, sufficient to insure an excess during digestion and digest for an hour on a steam
bath. Remove the free iodin with a few drops of sodium thiosulphate solution,
decant the clear liquid through a tared Gooch, retaining most of the precipitate,
tetraiodophenylenquinon (C6H2l20)2, in the flask. To the latter add 50 cc of
boiling water, digest 10 minutes on the steam bath, then filter, wash gradually
all the precipitate into a Gooch, using for this purpose and the final washing
about 200 cc. of hot water. Dry to constant weight in an air bath at 100°C. Mul-
tiply the weight of the precipitate by 0.4654 to obtain the quantity of sodium
salicylate present in the aliquot taken.

Should the mixture contain caffein or antipyrin, or both, these substances will
appear with the acetanilid in the first chloroform extract and may be determined
as directed in the closely set type following 10. Should the acetanilid be replaced by
acetphenetidin in the mixture, the general procedure would not be materially al
the acetphenetidin being weighed directly after recovery from its washed chloro-
form solution as separated from the sodium salicylate. If, instead of sodium sal-
icylate, the mixture contains the free acid or its ammonium salt, add a larger quan-
tity of sodium bicarbonate prior to extraction with chloroform to insure the fixation
of salicylic acid.

In the analysis of a mixture of caffein, acetanilid, sodium salicylate and codein
sulphate, the following procedure is recommended: (1) Extraction of caffein, acet-
anilid and salicylic acid from the acidified solution; (2) Washing the chloroform
solution with aqueous soda solution for the recovery of salicylic acid, preliminary
to its treatment with iodin solution; (3) Separation of caffein and acetanil
directed under 3 and 4; (4) Recovery of codein from the solution of its sul]
after treatment with sodium bicarbonate and chloroform.

XXIX] drugs 359

Caffein, Acetanilid and Quinin Sulphate in Mixtures.

21 preparation of sample and solution.— tentative.

Transfer to a separatory funnel one or more average unit doses of the powdered
sample, add 20 cc. of water and 50 cc. of chloroform, then 10 drops of dilute sulphuric
acid and extract in the usual way. After clearing, wash the solvent in a second
separatory funnel with 5 cc. of water prior to transferring to a 200 cc. Erlenmeyer
flask. Repeat the foregoing operations with two 50 cc. portions of chloroform,
finally distilling the combined chloroform solution to about 10 cc. by gentle heat.

22 CAFFEIN AND ACETANILID— TENTATIVE.

Treat the chloroform residue obtained in 21 as directed under 3 and 4.

23 QUININ SULPHATE.— TENTATIVE.

Combine the wash water, used in the second separatory funnel in 21, with the
solution of quinin bisulphate, add a slight excess of solid sodium bicarbonate, ex-
tract with three 50 cc. portions of chloroform, wash each portion with 5 cc. of water
in a second separatory funnel and then pass through a dry filter into a 200 cc. Erlen-
meyer flask. Distil by gentle heat to about 5 cc, evaporate on a steam bath
to apparent dryness, dissolve the amorphous alkaloid in 5 cc. of neutral alcohol
and titrate with N/50 hydrochloric acid to a faint red, using 2 drops of methyl red
as an indicator. Heat on a steam bath until most of the alcohol has been expelled,
adding, if necessary, sufficient acid to maintain the acid reaction. From the total
number of cc. of acid employed in the titration calculate the quinin sulphate. One
cc. of N/50 hydrochloric acid is equivalent to 8.73 mg. of quinin sulphate.

If the mixture contains acetphenetidin in place of acetanilid, proceed as out-
lined above, except that the separation of caffein and acetphenetidin is conducted
as directed under 6 and 7.

Caffein, Acetanilid and Codein Sulphate in Mixtures.

24 PRi;P\RVTIO^ O? SV^LS A^D 33'^jrO *.— T2Sr.\TlV2.
Proceed as directed under 21 .

25 CAFFEIN AND ACETANILID.-TENTATIVE.
Proceed as directed under 22.

26 CODEIN SULPHATE.-TENTATIVE.

Proceed as directed under 23 to the point indicated by the sentence "Distil by
gentle heat to about 5 cc". Transfer the chloroform solution of codein with suffi-
cient solvent to a small, tared beaker, evaporate to apparent dryness on a steam
bath, add a few drops of alcohol to the amorphous residue, then a like amount of
water and evaporate again. Final]}' cool and .allow the usually crystalline product
to stand until the weight becomes constant. The weighl of this residue multiplied
by 1.3144 gives the quantity of codein sulphate present.

This result should be checked volumetrically. Dissolve the residue in 3-5 cc. of
neutral alcohol and titrate with N/50 sulphuric acid to a fainl red, using methyl
red as an indicator. From t he number of cc. of standard acid employed calculate
the amount of codein sulphate. One cc. of N/50 sulphuric acid is equivalent to
7.87 mg. of codein sulphate. The quantity Of codein sulphate as found by weigh!
will usually be slightly greater than that determined by titration.

360 METHODS OF ANALYSIS [Chap.

Caffein, Acetanilid, Quinin Sulphate and Morphin Sulphate in Mixtures.

27 preparation of sample and solution.— tentative.

Transfer to a separatory funnel an amount (containing not less than one fourth
grain of morphin) of the powdered sample equal to, or a multiple of, a unit dose,
add 20 cc. of water and 10 drops of dilute sulphuric acid, then extract with three
50 cc. portions of alcohol-free chloroform, wash each portion in a second separatory
funnel with 5 cc. of water and add the combined washings to the alkaloidal solu-
tion in the first separatory funnel. Filter the chloroform extracts through a small,
dry filter into a 200 cc. Erlenmeyer flask and distil by gentle heat to about 10 cc.

28 CAFFEIN AND ACETANILID.— TENTATIVE.
Treat the chloroform residue as directed under 3 and 4.

29 QUININ SULPHATE.— TENTATIVE.

Add to the solution of quinin and morphin sulphates, obtained in 27, 4-5 cc. of
sodium hydroxid solution (1 to 10) and extract with four 40 cc. portions of chloro-
form, wash each portion with 5 cc. of water and pass the clear solvent through a
small, dry filter into a 200 cc. Erlenmeyer flask. Remove the solvent by gentle
distillation and titrate the residual quinin with N/50 hydrochloric acid as directed
under 23.

30 MORPHIN SULPHATE.— TENTATIVE.

Wash the filter, employed in 29, with 5 cc. of water and add to the aqueous
alkaline solution of the alkaloid. Now add 0.5 gram of ammonium chlorid (or an
amount slightly in excess of that required to free the morphin as well as convert
all sodium hydroxid to sodium chlorid) and, to the resulting ammoniacal solution,
add 45 cc. of chloroform and 5 cc. of alcohol, then extract in the usual way, washing
the solvent in a second separatory funnel with 5 cc. of water. After clearing, pass
the chloroform through a small, dry filter into a 200 cc. Erlenmeyer flask. Repeat
the extraction with three 40 cc. portions of chloroform, washing and filtering as be-
fore, finally collecting all the solvent in an Erlenmeyer flask and distilling to about
10 cc. Transfer with chloroform to a small, tared beaker, evaporate to apparent
dryness, add 0.5 cc. each of water and neutral alcohol, start crystallization by
stirring with a glass rod and finally evaporate to dryness. Cool and allow to stand
until the weight becomes constant.

Check the weight of morphin, thus determined, by titration with N/50 sulphuric
acid, using a drop of methyl red as an indicator. Dissolve the alkaloid in 1-2 cc.
of warm, neutral alcohol, then add the standard acid to a faint red. Evaporate
most of the alcohol on a steam bath, adding, if necessary, sufficient acid to main-
tain the acid reaction. From the volume of acid used calculate the morphin sul-
phate. One cc. of N/50 sulphuric acid is equivalent to 7.58 mg. of morphin sulphate.

TRAGACANTH.

31 VOLATILE ACIDITY6.— TENTATIVE.

The quantity of volatile (acetic) acidity developed in the acid hydrolysis of gum
tragacanth (Astragalus gummifer) affords a valuable index of the purity of this com-
modity when compared with results obtained by similar treatment of so-called
"Indian gum" (Cochlospernum gossypium and Sterculia urcns). The term "vola-
tile acidity" expresses the number of cc. of N/10 potassium or sodium hydroxid
required to neutralize the volatile (acetic) acid obtained by distilling with steam
the products of the action of boiling aqueous phosphoric acid on 1 gram of the gum.

XXIX] DRUGS 361

Treat 1 gram of the whole or powdered sample in a 700 cc. round-bottomed, long-
necked flask for several hours in the cold with 100 cc. of water and 5 cc. of sirupy
phosphoric acid until the gum is completely swollen. Boil gently for 2 hours under
a reflux condenser. A very small amount of cellulose substance will remain undis-
solved. Now distil the hydrolyzed product with steam, using a spray trap7 to con-
nect the distillation flask with the condenser and continue until the distillate
amounts to 600 cc. and the acid residue to about 20 cc. Do not concentrate too far,
as this would scorch the non-volatile, organic decomposition products and possibly
contaminate the distillate. Titrate the distillate with N/10 potassium hydroxid,
using 10 drops of phenolphthalein as an indicator, finally boiling the liquid under
examination until a faint pink color remains. Correct the result by a blank de-
termination and express the final result in terms of the number of cc. of N/10
alkali required, as in the above definition.

While tragacanth yields a practically colorless solution when boiled with aqueous
phosphoric acid, Indian gum, on the other hand, gives a pink or rose solution. This
reaction may be used as a preliminary test for the detection of Indian gum.

Levant Wormseed.

32 santonin.— tentative.

Extract 10 grams of the sample, ground to pass a 30 mesh sieve, in a Soxhlet ex-
traction apparatus for 3 hours with chloroform. Distil off the chloroform until
7-8 cc. remain; add 100 cc. of 5% barium hydroxid solution and heat on a steam
bath until the odor of chloroform has disappeared. Boil 5 minutes, cool and pass
carbon dioxid (washed through sodium bicarbonate solution to remove traces
of acid) until saturated. Filter on a small Biichner funnel, using suction, and wash
twice with 10 cc. of water. Heat the filtrate on a steam bath, add 5 cc. of 25%
hydrochloric acid and warm 5 minutes. Cool until lukewarm and extract with 20,
15 and 15 cc. of chloroform, passing the solvent through a small filter into a flask.
Evaporate to dryness, removing the last traces of chloroform. Dissolve in 7.5
grams (9.5 cc.) of absolute alcohol, warming gently if necessary. Then add 42.5
cc. of water heated to 60°-70°C, stopper the flask and allow to cool. Start crystal-
lization at this point by scratching the side of the flask with a rod or by seeding with
a minute crystal of santonin. (Solutions containing a liberal amount of santonin,
kept in a cool place for 24 hours, have been found in a supersaturated condition
where this precaution was not observed.) Maintain the flask and contents at a
temperature of 15°-17°C. for 24 hours. Filter and wash at 15°-17°C. with two 10
cc. portions of 15% alcohol by weight. Dry the flask and filter at 100°C, dis-
solve the santonin left in the flask and on the filter in chloroform and filter into a
tared beaker. Wash the flask and paper thoroughly with chloroform, evaporate
the combined filtrate and washings, dry at 100°C. to remove all traces of chloroform
and weigh. To the weight found add 0.04 gram for the santonin dissolved in the
dilute alcohol and multiply the total by 10 to obtain the per cent of santonin.

Nitroglycerin in Tablets.

33 preparation of sample.— tentative.

(a) Crush 25 tablets under 10 cc. of anhydrous ether in a 25 cc. cylinder by
means of a stout glass rod. Kinse the rod with a little anhydrous ether, allow
the insoluble material to settle and decant the solution into a 50 cc. gra luated
flask. Wash the residue repeatedly with 5 cc. portions of anhydrous ether, decant
the washings into the flask until it is filled to the mark, stopper and mix well.
Designate this solution as .1.

362 METHODS OF ANALYSIS [Chap.

Add 10 cc. of water to the residue, mix well and transfer the mixture to a
small separatory funnel by means of a little water. Extract with 3 successive
portions of 10, 5 and 5 cc. of ether. Collect the ether extracts in a 50 cc. beaker
and designate this solution as B.

(b) Dis'ntegrate 25 tablets in a small beaker with 10 cc. of water, breaking
up any lumps with a glass rod, and transfer by means of a little water to a sepa-
ratory funnel. Rinse the beaker with 10 cc. of ether and transfer this also to the
funnel. Shake thoroughly, draw off the aqueous layer and transfer the ether
through a funnel, containing a little cotton, to a 50 cc. graduated flask. Repeat
the extraction with successive portions of ether until the flask is filled to the mark,
stopper and mix well. Designate this solution as C.

In hand-made and soft compressed tablets, the method described under Ca) is
preferred, since the direct extraction of the dry crushed material with ether re-
moves most of the nitroglycerin. In hard compressed tablets, the direct extraction
is often not nearly so complete and, in such cases, the method described under (b)
is to be preferred.

Nitrate Method8. — Tentative.

34 REAGENTS.

(a) Phenoldisulphonic acid solution. — Prepare as directed under IV, 14 (a).

(b) Standard nitrate solution. — Dissolve 0.7217 gram of potassium nitrate in 1
liter of water. Evaporate 10 cc. of this solution just to dryness in a porcelain dish
on a steam bath. Cool and treat the residue with 2 cc. of the phenoldisulphonic
acid solution, rubbing with a glass rod to insure intimate contact. After .5-10 min-
utes dilute to 250 cc. Each cc. of this solution contains 0.004 mg. of nitrogen. Add
an excess of potassium hydroxid solution to an aliquot of this solution and dilute
to 100 cc. (Do not use solium or ammonium hydroxid.) It is advisable to pre-
pare a standard of approximately the same color as the unknown.

35 DETERMINATION.

Place 20 cc. of the ether solution, A or C under 33, in a dried, tared 50 cc. beaker.
Evaporate the solvent in a vacuum desiccator containing sulphuric acid. Apply
the vacuum gradually, to prevent boiling. Allow the beaker to remain in the
vacuum 30 minutes after the ether has evaporated. Weigh and calculate the ether
extract per tablet. Treat the residue with 2 cc. of the phenoldisulphonic acid solu-
tion, rotating the beaker so that the reagent comes in contact with the entire inner
surface. After 10 minutes add water and wash into a 100 cc. flask. Dilute to the
mark and place 10 cc, representing 1 tablet, in a 100 cc. flask, add about 50 cc. of
water and a few drops more of 20% potassium hydroxid solution than is required to
neutralize the acid. Dilute to the mark and compare the color with that pro-
duced when a standard nitrate solution is similarly treated. Any convenient col-
orimeter or Nessler tubes may be used. Multiply the nitrate nitrogen found by
5.4 to obtain the equivalent of nitroglycerin.

When 33 (a) is used for the p eparat on of the sample, a correction, deter-
mined as directed in 37, should be made for the amount of nitroglycerin in B
under 33, using all of B instead of an aliquot.

Nitrite or Modified Hay Method9. — Tentative.

36 REAGENTS.

(a) Sulphanilic acid solution. — Prepare as directed under IV, 12 (D).

(b) Alpha-naphtkylamin hydrochlorid solution, — Prepare as directed under IV,
12 (c).

XXIX] drugs 363

(C) Standard nitrite solution. — Weigh out 0.220 gram of dry silver nitrite [XV,
18 (C)], dissolve in a small quantity of hot water and decompose with a slight ex-
cess of sodium chlorid solution.' When the solution becomes clear, dilute to 1 liter
with nitrite-free water. Dilute 5 cc. of this solution to 1 liter with nitrite-free water.
The second dilution, containing 0.0001 mg. of nitrous nitrogen per cc, is the stand-
ard to be used. [Cf. IV, 12 (d)]

37 DETERMINATION.

Place 5 cc. of the ether solution, A or C under 33, in a 50 cc. beaker
dilute with 5-10 cc. of alcohol and add about 5 cc. of 0.5% alcoholic potassium hy-
droxid. Cover with a watch glass and allow to stand 10 minutes. Place on a steam
bath, boil, remove the watch glass and, when most of the liquid has evaporated, add
about 25 cc. of water and return to the steam bath until about half the liquid has
evaporated or until the odor of alcohol can no longer be detected. Cool and dilute
with nitrite-free water to 250 cc. Each cc. of this solution represents 0.01 of a
tablet. Introduce an aliquot, representing 0.02-0.04 mg. of nitroglycerin, into a
100 cc. graduated flask, dilute with sufficient nitrite-free water to make the volume
90-95 cc, add a drop of concentrated hydrochloric acid, then 2 cc. of the sulphanilic
acid solution and 2 cc of the alpha-naphthylamin hydrochlorid solution. Com-
plete the volume with nitrite-free water. Prepare at the same time and in the same
manner standards containing known amounts of sodium nitrite. Stopper the flasks,
mix well and compare the colors after 30 minutes, using any convenient colorimeter
or Nessler tubes. Multiply the nitrite nitrogen found by the factor 8, which has
been determined experimentally, to obtain the equivalent of nitroglycerin.

When 33 (a) is used for the preparation of the sample, a correction, deter-
mined as directed above, should be made for the amount of nitroglycerin in B
under 33, using all of B instead of an aliquot.

Pepsin in Liquids.-tentative.

38 REAGENTS.

(a) Standard pepsin. — Powder a good grade of U. S. P. pepsin and pass it through
a No. 60 sieve; dry in vacuo over calcium chlorid, again pass through a sieve and
preserve in a stoppered bottle. Ascertain the exact pepsin equivalent of the dry
powder by the U. S. P. method10 and express in percentage based on the as sum
that the U. S. P. product is 100% pure.

(b) Standard pepsin solutions. — Weigh off definite amounts of the standard pep-
sin into the requisite quantity of N/10 hydrochloric acid to make solutions con-
taining 5 and 0.5 mg. of pepsin per cc. These should be freshly prepared.

(C) Ricin solution. — Grind commercial ricin, similar to the "Ricin Pre pa rat nach
Jacoby", to a No. 60 powder, mix thoroughly, dry and keep in a desiccator. Digest
1 gram of this powder for an hour at 37.5°C. in 100 cc. of 5% sodium chlorid solution,
cool, filter and use at once for the assay.

39 PREPARATION OF SOLUTIONS.

(a) Dilute solution of the sample. — Dilute the sample with a measured amount of
N/10 hydrochloric acid until, upon digestion at 37.5°C, 1 cc. requires approximately
15 minutes to digest the precipitate obtained by mixing 2 cc of the ricin solution
and 0.5 cc. of N/10 hydrochloric acid. To 50 cc. of this diluted preparation add the
requisite quantity of water or of N/5 hydrochloric acid to make the preparation of
N/10 acid strength when diluted with N/10 acid to 90 cc. Preserve the simple in

364 METHODS OF ANALYSIS [Chap.

a refrigerator. (Solid pepsin preparations may often be extracted with hydro-
chloric acid of appropriate strength and prepared for assay in the same manner.)

(b) Dilute comparison solution of the sample. — Add 1 cc. of N/10 hydrochloric
acid to 9 cc. of the dilute solution of the sample.

(C) Dilute inactive solution of the sample. — Immerse a stoppered glass vessel, con-
taining 45 cc. of the dilute solution of the sample and 5 cc. of N/10 hydrochloric
acid, in boiling water for 15 minutes and filter.

(d) Standard solution containing 0.5 mg. of active U. S. P. pepsin per cc. — Im-
merse a stoppered test tube containing 18 cc. of the dilute solution of the sample
in boiling water for 10 minutes and, after cooling, add 2 cc. of the standard pepsin
solution, containing 5 mg. of pepsin per cc, and filter if necessary.

If the solutions to be tested are not clear, filter through hardened filters. If,
however, they cannot thus be clarified, make check comparison tubes containing
the same amounts of the preparation made up in the same way with 2 cc. of water
in place of the ricin solution used in the determination.

40

DETERMINATION.

To each of 15 tubes, add from a burette 2 cc. of the ricin solution and 0.5 cc. of
N/10 hydrochloric acid, heat to 37.5°C. and add the following quantities of the
solutions:

To the first 5 tubes, add 0.00-1.00 cc. of the dilute comparison solution of the
sample in 0.25 cc. increments, and 1.00-0.00 cc. of the dilute inactive solution of
the sample in 0.25 cc. decrements. To the next 5 tubes, add 1.00-0.00 cc. of the
dilute inactive solution of the sample in 0.25 cc. decrements and 0.00-1.00 cc. of the
standard solution containing 0.5 mg. of active U. S. P. pepsin per cc. in 0.25 cc.
increments. To the last 5 tubes, add 1.00-0.00 cc. of N/10 hydrochloric acid in
0.25 cc. decrements and 0.00-1.00 cc. of the standard pepsin solution containing 0.5
mg. of pepsin per cc. in 0.25 cc. increments.

By comparing any tube of the first group of 5 with the tubes in the remaining
groups the degree of proteolytic activity of the dilute comparison solution of the
sample may be matched against known amounts of standard pepsin both in ordi-
nary acid medium, last group of 5, and in the same medium as the sample itself,
second group.

Introduce the acid and the dilute inactive solution of the sample into the tubes
first and then pour in the solutions to be tested as rapidly as possible from gradu-
ated pipettes, noting the total time consumed in the process after adding the pepsin.

After the addition of the solution to be tested, again immerse the test tubes in
the 37.5°C. bath, preferably arranged in corresponding order in a partitioned square
or oblong wire rack, such as is used in bacteriological work. Shake and examine the
tubes from time to time for 1-2 hours, noting the time when the digestion begins
and ends. In case of very weak solutions they may be allowed to digest over-
night.

If the rate of digestion is the same in each group, the dilute comparison solution
of the sample contains exactly 0.5 mg. of pepsin per cc. If the rate is more rapid
in the first group than in the others, it is stronger, the comparative strength being
closely indicated by the time of action in the tube containing less of the solution.
If the rate of clearing is more rapid in the last group than in the second, some in-
terfering substance is present and must be removed by dialysis, or by evaporation
in vacuo at a low temperature until, upon re-examination and further dilution or
concentration, the rate of digestion is identical or nearly so in each series.

Smaller quantities of pepsin may be determined in the same way by comparing

XXIX] drugs 365

them with more dilute solutions of standard pepsin. Thus 0.05 mg. of U. S. P.
pepsin can be readily detected by the nearly complete solvent action on the ricin
precipitate in less than 2 hours. A marked action on the ricin within the same time
is shown by 0.005 mg. For all practical purposes the absence of an appreciable sol-
vent action after 4 hours digestion indicates the absence of pepsin. Express the re-
sult in per cent, assuming U. S. P. pepsin to be 100% pure and calculating the
result according to the dilution found necessary in preparing the dilute solution
of the sample.

Turpentine.

41 color.— tentative.

Fill a 200 cc. flat-bottomed colorimeter tube, graduated in mm., to a depth of
40-50 mm. with the turpentine. Place the tube in a colorimeter and place on or
under it a No. 2 yellow Lovibond glass. Over or under a second graduated tube
in the colorimeter, place a No. 1 yellow Lovibond glass and run in the same turpen-
tine until the color matches as nearly as possible the color in the first tube. Read
the difference in depth of the turpentine in the 2 tubes. If this difference is 50 mm.
or more, the turpentine is "standard".

42 SPECIFIC GRAVITY. -TENTATIVE.

20* C
Determine the specific gravity at -p — '- by means of a pycnometer. The specific

gravity may also be determined somewhat less accurately at any convenient tem-
perature with a plummet, correcting the result by using the factor 0.00082 for each
degree that the temperature of the determination differs from the standard tem-
perature.

43 REFRACTIVE INDEX. -TENTATIVE.

Determine the refractive index at any convenient temperature with an accurate
instrument and calculate the result to 20°C, using the correction factor 0.00045
for each degree that the temperature of the determination differs from 20°C.

44 DISTILLATION. -TENTATD7E.

Use an ordinary Engler flask (the internal diameter of the side tube must be 6-7
mm.) and condenser11 and heat the flask in a glycerin or oil bath12. Fit the flask
with a thermometer reading 145°-200°C. Place 100 cc. of the turpentine in the
flask, connect with the condenser and distil. Conduct the distillation so that the
distillate passes over at the rate of 2 drops per second. Note the initial distilling
temperature and the percentage distilling below 170°C.

POLYMERIZATION. -TENTATIVE.

45 REAGENT.

S8N sulphuric acid. — Mix 140 grams of concentrated sulphuric acid with sufficient
liquid, fuming sulphuric acid (about 10 grams) to obtain an acid slightly stronger
than 38N. Determine the exact strength13 of this mixture and also of the concen-
trated acid as follows: Weigh out 6-8 grams in a bulb, having a capillary tube in t ho
lower end and a tube with a stop-cock in the upper end, fitted with a platinum
wire for suspending on a balance. (The bulb is filled by (lie aid of a slight vacuum,
and the lower end of the capillary is emptied by closing the stop-cock simultaneously
with the withdrawal of the capillary from the acid; after which it is wiped <>tY first
with a wet and then with a dry piece of cloth.) Run the acid into cold water, make
up to volume and titrate an aliquot of the solution against standard alkali or add an

366 METHODS OF ANALYSIS

excess of ammonium hydroxid to an aliquot, evaporate to dryness, dry to constant
weight at 120°-130°C. and weigh as ammonium sulphate. Calculate the sulphur
trioxid content of the acid and add sufficient concentrated sulphuric acid to make
it exactly 82.38% of S03. The acid must be carefully protected against absorption
of water from the air.

46 DETERMINATION.

Place 20 cc. of the 38N sulphuric acid (100.92%) in a graduated, narrow-necked
Babcock flask, stopper, place in ice water and cool. Add slowly 5 cc. of the turpen-
tine. Mix the contents gradually, cool from time to time and do not allow the tem-
perature to rise above 60°C. When the mixture no longer warms up on shaking, agi-
tate thoroughly, place in a water bath and heat to 60°-65°C. for about 10 minutes,
keeping the contents of the flask thoroughly mixed by vigorous shaking 5-6 times.
Cool to room temperature and fill the flask with concentrated sulphuric acid until
the unpolymerized oil rises into the graduated neck. Centrifugalize 4—5 minutes at
about 1200 revolutions per minute, or allow to stand for 12 hours. Read the un-
polymerized residue, notice its consistency and color and determine its refractive
index.

BIBLIOGRAPHY.

i U. S. Bur. Chem. Bull. 152, p. 239.

2 J. Ind. Eng. Chem., 1915, 7: 519.

3 Ibid., 1914, 6: 665.

* U. S. Bur. Chem. Bull. 162, p. 197.

6 J. Ind. Eng Chem. 1915, 7: 681.
r' Ibid., 1912, 4:374.

7 U. S. Bur. Chem. Circ. 94, p. 4.

8 Am. J. Pharm., 1911, 83: 359.

9 Trans. Roy. Soc. Edinburgh, 18S5, 32: 67.

10 U. S. P., VIII, 1905, p. 334.

11 Stillman. Engineering Chemistrv. 4th ed., 1910, p. 503.

12 U. S. Bur. Chem. Bull. 135, p. 26.

13 U. S. Bur. Chem. Circ. 85, p. 12.

INDEX

Abrastol 151

Acetanilid 352, 356, 358, 359, 360

and acetphenetidin, in mixtures 354

sodium salicylate, in mixtures 357

Acetphenetidin (phenacetin) 353, 354, 356

and salol, in mixtures 356

Acetyl value, of fats and oils 310

Acidity, in cheese 296

cream of tartar 343

distilled liquors 243

prepared mustard , 322

total, in coffees 333

fruits and fruit products 178

tanning liquors 55

volatile, in coffees 333

water-soluble, of feeds 119

Acids, fixed, in tomato products 324

vinegars 256

wines 240

insoluble, in fats and oils (Hehner number) 307

mineral, free, in fruits and fruit products 17!)

vinegars 258

soluble, in fats and oils 306

total, in beers 251 >

canned vegetables 186

tomato products 324

vinegars 256

wines 238

volatile, in beers 250

canned vegetables 186

fruits and fruit products 178

tomato products 324

vinegars 256

wines 239

insoluble, in fats and oils (Polenske number) 308

soluble, in fats and oils (Reichert-Meissl number) 307

Agar agar Is;

Albrech Method for lemon and orange peel color

Albumin, in milk

wheat flour 188

Alcohol, in beers 249

confectionery

distilled liquors 243

flavoring extracts '. 266, 267

367

368 INDEX

Alcohol, in fruits and fruit products 177

vinegars 253

wines 193

extract, in spices 318

precipitate, in fruits and fruit products 179

vinegars 257

Aldehydes, in distilled liquors 244

total, in flavoring extracts 262, 265

Alkali, black, in irrigating water 51

Alkalies, total, in soils 27

Alkalinity, in industrial water 50

Allihn's Method for dextrose 106

Almond extract 266

Alum, in baking powders 345

Aluminium, in soils 22

waters 43

oxid, in plants 30

Amaranth 158

Ammonia, in baking powders 346

meat and meat products 274, 281

free and albuminoid, in waters 36, 41

Amthor Test Modified by Lasche for caramel 248

Anise extracts 269

Annatto 168

Antipyrin 354

Arsenic, in baking powders 350

foods 171

mineral water 48

oxid, total, in insecticides and fungicides 66

water-soluble, in insecticides and fungicides 67, 68, 72

total, in insecticides and fungicides 63, 68, 69, 71, 72

Arsenious oxid, sodium acetate-soluble, in insecticides and fungicides 65

total, in insecticides and fungicides 64, 66, 69, 71

water-soluble, in insecticides and fungicides 65, 67, 72

Ash, in baking powders 345

beers 250

cacao products 327

canned vegetables 185

coffees 331

dairy products 287, 292, 293, 294, 296

distilled liquors 243

flavoring extracts 260, 264

foods and feeding stuffs 79

fruits and fruit products 178

leathers 59

meat and meat products 271, 2S0

plants 29

saccharine products 128, 133, 137

spices and other condiments 317, 321, 323

tea 335

vinegars 256

INDEX 369

Ash, in wheat flour 187

wines 238

Babcock Method for fat in dairy products 289, 292, 298

Bacteria, in tomato pulp, etc 325

Baking powders 339-350

Bamihl Test for gluten in wheat flour 189

Baudoin Test for sesame oil 314

Beef fat, in lard 314

Beers 249-251

Benedikt-Lewkowitsch Method for acetyl value in fats and oils 310

Modified, for moisture in soap 73

Benzaldehyde, in almond extract 266

Benzoic acid 143-145

Beta-Naphthol 151

Blarez Method, Modified, for fluorids 149

Borates 146

Bordeaux mixture 69

with lead arsenate 72

Paris Green 71

Boric acid 146

in mineral water 49

Bromin, in mineral water 47

Butter 294

renovated 295

Butyric acid, in tomato products 324

Cacao products 327-330

Caffein, in coffees - 332

drugs 352, 353, 354, 359, 360

tea 336

and acetanilid, in mixtures 351

acetphenetidin (phenacetin), in mixtures 353

antipyrin, in mixtures 353

acetanilid and codein sulphate, in mixtures 359

quinin sulphate, in mixtures 359

and morphin sulphate, in mixtures. . . 360

( 'alcium, in mineral water 43, 50, 51

plants 31

soils 2:?

arsenate 69

carbonate required, in soils 28

( 'aimed vegetables 185-1S6

Capsicum, in ginger ext ran

Caramel, in distilled liquors 248

Carbon, inorganic, in soils 19

in plants '-"•'

organic, in soils Is'

dioxid, in insecticides and fungicides 70, 71 , 72

mineral water 42

plant ash 29

available, in baking powders

370 INDEX

Carbon, dioxid, residual, in baking powders

total, in baking powders 330

Carbonic and bicarbonic acids, in waters 42, 4^

Casein, in dairy products 287, 20 \

milk chocolate 329

Cassia extract 267

Cereal foods 187-10 1

Chace Method for pincne 26.")

total aldehydes in flavoring extracts 262, 265

Cheese 296

Chicory, in coffee 334

Chlorin, in butter 294

cyanids 73

meat extracts 280

plants 32, 33

waters 38, 41, 49, 51

wheat flour 189

wines 23S

Chlorophyll 168

Cholesterol and phytosterol, in mixtures of animal and vegetable fats 311

Cinnamon extract 267

Citral, in flavoring extracts 263, 265

Citric acid, in fruits and fruit products 182

Clarifying reagents for optical methods

Clove extract 267

Coating and glazing substances, in coffees 333

Cochineal 168

Codein sulphate 359

Coffee, green 331

roasted 331

Coffees 331-334

Color, in beers 249

potable water 35

vinegars _'57

residual, in vanilla extract 261

value, in vanilla extract 261

wheat flour 191

water-insoluble, in whiskies 24^

Coloring matters 15a

in dairy products 292

wines 240

natural 163, 168

separation by immiscible solvents 157

Colors, insoluble in amyl alcohol, in distilled liquors 24s

vanilla extract 261

Condensed milk (sweetened) 293

(unsweetened) 293

Condiments :; !

Cook Method for glycerol in meal exl racts 285

Copper, in foods 1 7"i

INDEX 371

Copper, in insecticides and fungicides 70, 71, 72

carbonate 69

oxid, total, in insecticides and fungicides 65

reducing substances in spices and other condiments 318, 322

Cottonseed oil 313

Coumarin, in vanilla extract 259

Cowles Method for malic acid value 138

Cream 292

of tartar in wines 240

Creatin, in meat and meat products 275, 284

Creatinin, in meat extracts 285

Crude fiber, in cacao products 327

coffees 333

foods and feeding stuffs 118

spices and other condiments 318, 322

tea 336

wheat flour 187

Cyanids, sodium and potassium 72

Dairy products 287-298

Dextrin, in beers 250

fruits and fruit products 179

honey 134

vinegars 258

wines 241

Dextrose, in foods and feeding stuffs 106

honey 134

Diastase, in honey 136

Distilled liquors 243-248

Drugs 351-366

Dulcin 152

Dyes, acid 159

basic 159

coal tar 155

oil-soluble 156

Emery Method for beef fat in lard 314

Erythrosine 158

Esters, in distilled liquors. . LM4

Ether extract, in butter . 294

confectionery 131

foods and feeding stuffs 80

meat 271

prepared mustard

wheal (lour 187

volatile and non-volatile, in spices . 318

Extract, in beers

distilled liquors 243

wines 236

cold water-soluble, in wheat flour 188

372 INDEX

Facing, in tea 337

Fat, in cacao products 328

coffees 334

dairy products 289, 292, 293, 295, 297

leathers 59

meat extracts 280

Fats and oils 299-315

Fatty acids, free, in fats and oils 310

liquid and solid, in fats and oils 309

Feder Anilin Chlorid Test for commercial invert sugar 136

Ferric oxid, in plants 30

Fertilizers 1-15

Fiehe Test (Bryan Modification) for commercial invert sugar 135

Fincke Method for formic acid in vinegars 257

Fish oil, in the presence of vegetable oils 315

Flavoring extracts 259-269

Flour, wheat 187

Fluoborates 149

Fluorids 149

Fluosilicates 149

Folin Aeration Method for ammonia in meat 274

Food preservatives 141-154

Foods and feeding stuffs 79-119

Formaldehyde 147-149

solutions 75

Formic acid 152

in vinegars 257

Fruit products 177-184

Fruits 177-184

Fungicides 63-77

Furfural, in distilled liquors 244

Fusel oil, in distilled liquors 245

Galactan, in foods and feeding stuffs 118

Gelatin, as coating substance, in coffees 334

dairy products 291, 293

fruits and fruit products 180

meat and meat products 274, 281

Ginger, in ginger extract 268

cold-water extract 318

extract 267

Glazing substances, in coffees 333

Globulin, in wheat flour 188

Glucose, in leathers 60

commercial, in fruits and fruit products 179

saccharine products 130, 135

wines 237

Gluten, in wheat flour 189

Glutenin, in wheat flour 188

Glycerol, in beers 250

flavoring extracts 259, 262

INDEX 373

Glycerol, in meat extracts 285

vinegars 253

wines 236

Glycogen, in meat 276

Goldenberg-Geromont-Heidenhain Method for total tartaric acid in baking powders 343

Gorier Method for caffein in coffee 332

Gum, in wines 241

Gunning Method for organic and ammoniacal nitrogen in fertilizers 7

Modified, for total nitrogen in fertilizers 8

Halphen Test for cottonseed oil 313

Hanus Method for iodin absorption number of fats and oils 305

Hardness, permanent, in industrial water 51

temporary, in industrial water 50

total, in industrial water 51

Hay Method, Modified, for nitroglycerin in tablets 362

Hedges Method, Modified, for total arsenious oxid in insecticides and fungicides 64

Hehner Method for formaldehyde 147

free mineral acids in vinegars 258

number, of fats and oils 307

Herzfeld Gravimetric Method for invert sugar 98

Modification of the alcohol extraction method for sucrose in beets. . . . 138

Sachs le Docte Method for sucrose in beets 139

Hess and Prescott Method, Modified, for vanillin and coumarin 259

Hide substance, in leathers 61

Hiltner Method for citral in flavoring extracts 263, 265

Honey 133-136

Hortvet Method for volatile acids in wines 239

and West Method for oil in anise and nutmeg extracts 269

cassia, cinnamon and clove extracts 267

Modified, for methyl salicylate in wintergreen extract 269
Howard Method, Modified, for oil in peppermint, spearmint and wintergreen ex-
tracts 268

Hubl Method for iodin absorption number of fats and oils 304

Hydrocyanic acid, in almond extract 266

Hydrogen sulphid, in mineral water 41

Indigo carmine 158

Insecticides 63-77

Insoluble residue, in soils 22

Invert sugar, in foods and feeding stuffs 85

commercial, in honey 135

Iodin, in mineral water 47

absorption number of fats and oils 304

Iron, in mineral water 43

soils '-"-'

and aluminium in mineral water 42, 50

Jorissen Method for sucrol or dulcin 152

Test for salicylic acid 142

374 INDEX

Kissling Method for nicotin in tobacco and tobacco extract 73

Kjeldahl Method for organic and ammoniacal nitrogen in fertilizers 5

Modified, for total nitrogen in fertilizers 8

-Gunning -Arnold Method for organic and ammoniacal nitrogen in ferti-
lizers 7

Kleber Method for citral in lemon and orange oils 265

Koettstorfer number of fats and oils 306

Lactose, in cacao products 329

dairy products 288, 292, 293

foods and feeding stuffs 104

La Wall Method, Modified by Doyle, for capsicum in ginger extract 268

Leach and Lythgoe Method for methyl alcohol in distilled liquors 247

Method for coloring matters in milk 292

formaldehyde 148

Lead, in baking powders 346

arsenate 67-69

number, in maple products 137

vanilla extract 260

oxid, total, in insecticides and fungicides 67, 72

precipitate, in vinegars 255

Leathers 59-61

Leffman and Beam Method for soluble volatile acids in fats and oils 308

Lemon extracts 261

oil 264

in lemon extract 262

and orange peel color 264

Levant Wormseed 361

Levulose, in honey 134

Light Green S F yellowish 159

Lime-sulphur solutions 76-77

Lindo-Gladding Method for potash in fertilizers 12

Lithium, in mineral water 45

London purple 66-67

Low, A. H., Volumetric Method, Modified, for determining the amount of reduced

copper 96

Lowenlhal Method, Proctor Modification, for tannin in tea 336

Magnesium, in mineral water 44, 50, 51

plants 31

soils 23

Malic acid, in fruits and fruit products 181

value, in maple products 138

Maltose, in foods and feeding stuffs 102

Manganese, in mineral water 47

plants 31

soils 23

Maple products 136- 138

Marcusson and Schilling Method for cholesterol and phytosterol 312

Marr Method, Modified, for inorganic carbon in soils 19

Marsh Method, Modified, for color insoluble in amyl alcohol 248

INDEX 375

Mayrhofer Method, Price Modification, for starch in meat 276

McGill Method, Modified, for starch in baking powders 345

Meat 271

bases in meat 274

extracts 280

and meat products 271-286

Melting point determinations 301

Metals, in foods 171-176

Methyl alcohol, in distilled liquors 246

flavoring extracts 261, 264

salicylate, in wintergreen extract 269

Micro-analysis of tomato pulp, ketchup, puree and sauce (paste) 324

Milk 287-292

fat, in milk chocolate 328

Mitchell Method for lemon and orange oils 262

Mohler test, Modified, for benzoic acid 144

Moisture, in cacao products 327

canned vegetables 185

coffees 331

dairy products 294, 296

fertilizers 1

foods and feeding stuffs 79

insecticides and fungicides 63, 66, 67, 69, 71, 72

leathers 59

meat and meat products 271 , 280

saccharine products 121, 133, 136

soils 17

spices 317

tea 335

wheat flour 187

Molds, in tomato pulp, etc 324

Morphin sulphate 360

Morpurgo Method for sucrol or dulcin 152

Munson and Walker Method for reducing sugars 86

Mustard, prepared 321

Muter Method, Modified by Lane, for liquid and solid fatty acids 309

Naphthol Yellow S 158

Nitrates, in fertilizers 5

meat and meat products 278, 285

wines 241

Nitrobenzol, in almond extract 267

Nitrogen, in fertilizers 5-12

leathers 61

nitrate salts, in fertilizers 11

non-volatile ether extract, in spices 317

saccharine products 129

albuminoid, in foods and feeding stuffs 80

alcohol-soluble, in meal extracts 284

amino, in foods and feeding stuffs 80

meat extracts 282

376 INDEX

Nitrogen, amino, in wheat flour 188

ammoniacal, in fertilizers 10

connective tissue, in meat 273

nitrate, in waters 37, 41. 49

nitric and ammoniacal, in fertilizers 10

nitrite, in waters 37, 41

wheat flour 190

organic and ammoniacal, in fertilizers 5

in fertilizers 11

soluble and insoluble, in meat 273

total, in cacao products 327

dairy products 287, 292, 296

fertilizers 8-10

meat and meat products 273, 280

soils 21

spices 317

Nitroglycerin, in tablets 361

Nontannins, in tanning materials 54, 55

Nutmeg extracts 269

Odor, in potable water 35

Oil, in anise and nutmeg extracts 269

cassia, cinnamon and clove extracts 267

peppermint, spearmint and wintergreen extracts 268

Oleomargarine 295

Olive oil, in paprika 319

Orange extract 261

oil 264

in orange extract 262

1 158

Oxygen, dissolved, in potable water 40

required, in potable water 39

Paraffin, in confectionery 132

tea 337

Paris Green 63-66

Peanut oil 313

Pellet Aqueous Method for sucrose in beets 139

Pentosans, in foods and feeding stuffs 110

vinegars 257

wines 241

Peppermint extract 268

Pepsin, in liquids 363

Peptones, in meat and meat products 274

Petroleum ether extract, in coffees 333

tea 335

Phosphoric acid, in baking powders 346

beers 250

fertilizers 1-5, 14

mineral water 46

plants 31

INDEX 377

Phosphoric acid, in soils 22, 24

wines 238

soluble and insoluble, in vinegars 256

Phosphorus, soluble in N/5 nitric acid, in soils 27

total, in meat and meat products 271, 280

soils 25

water-soluble, in meat 271

Phytosterol, in mixtures of animal and vegetable fats 311

Pigments 155

used in tea for coloring or facing 337

Pinene, in lemon and orange oils 265

Plant constituents 29-33

Polarization, in foods and feeding stuffs 83, 84

fruits and fruit products 179

saccharine products 129, 133, 136

vinegars 255

wines 237

direct, in beers 250

Polenske Method for insoluble volatile acids in fats and oils 308

number, of fats and oils 308

Ponceau 3R 158

Potash in fertilizers 12-14

Potassium, in mineral water 45

plants 32

soils 24

total 26

bitartrate in baking powders 344

Preservatives, in foods 141-154

milk 291

wines 242

Protein, in beers 251

condensed milk 293

fruits and fruit products 179

prepared mustard 322

tea 336

wheat flour 187

alcohol-soluble, in wheat flour 187

coagulable, in meat and meat products 274, 281

crude, in foods and feeding stuffs 80

wines 241

insoluble, in meat extracts 281

Proteoses, in meat and meat products 274, 281

Quinin sulphate 359, 360

Raffinose, in beet products s '

Raw sugars, general directions for optical methods 81

Read Method for pigments used in tea for coloring or facing 337

Reducing substances, total, before inversion, in vinegars -55

sugars, in beers -50

foods and feeding stuffs 85, 109

378 INDEX

Reducing sugars, in fruits and fruit products 179

saccharine products 131, 134, 137

wines 237

after inversion, in tomato products 324

vinegars 255

before inversion, in tomato products 323

vinegars 255

other than dextrose, in foods and feeding stuffs 109

Refractive index, of fats and oils 300

lemon and orange oils 264

Reichert-Meissl Method for soluble volatile acids in fats and oils 307

number, of fats and oils 307

Renard Test, Modified, for peanut oil 313

Resin oil 313

Riche and Bardy Method for methyl alcohol in distilled liquors 246

Rimini Method for formaldehyde 148

Roese-Goltlieb Method for ether extract in confectionery 131

fat in dairy products 289, 293

Saccharin 145

Saccharine products 121-139

Sachsse Method, Modified, for starch 110

Salicylic acid 141-143

Salol, in drugs 357

Salt, in canned vegetables 185

dairy products 294, 296

prepared mustard 321

Sand, in plants 29

tomato products 323

Sangle-Ferriere Method for abrastol 152

Saponification number of fats and oils (Koettstorfer number) 306

Schlosing -Wagner Method for nitrates in meat 278

Schmidt-Bondzynski Method, Modified, for fat in cheese 297

Schulze-Trommsdorf Method for required oxygen in water 39

Seeker Method for ginger in ginger extract 268

Serum, acetic, in milk 291

copper, in milk 291

sour, in milk 291

Sesame oil 314

Silica, in mineral water 42, 49

plants 29

Sinibaldi Method for abrastol 151

Slag, Thomas or basic 14-15

Smith, J. Lawrence, Method for total alkalies in soils 27

Method, Modified, for total arsenious oxid in insecticides and fungicides . 65

Soap 73

Soda lye 73

Sodium, in mineral water 45

plants 32

soils 24

chlorid, in tomato products 323

INDEX 379

Sodium salicylate 358

Soils 17-28

Solids, in dairy products 287, 292, 293

flavoring extracts 260, 264, 267

fruits and fruit products 177

leathers 61

saccharine products 122

spices and other condiments 321, 323

tanning materials 53, 55

vinegars 255

waters 35, 41, 49, 51

insoluble, in tomato products 323

non-sugar, in wines 237

soluble, in coffees 331

Soxhlet Method for dextrose 106

invert sugar in foods and feeding stuffs 86

Wein Method for lactose 104

Spdth Method for fats and waxes in coffee 334

Spearmint extract 268

Special tests for coal tar dyes permitted under the Federal Food and Drugs Act. 162

Specific gravity, in beers 249

distilled liquors 243

fats and oils 299

flavoring extracts 259, 261, 264

saccharine products 122

vinegars 253

wines 193

Spices 317

microscopic examination of 319

and added pungent materials in vinegars 258

other condiments 317-326

Spores, in tomato pulp, etc 325

Stahlschmidt Method, Modified, for caffein in coffee 332

Starch, in baking powders 344

cacao products 328

coffees 333

foods and feeding stuffs 110

fruits and fruit products 180

meat 276

saccharine products 131

spices 318

Strontium, in mineral water 44

Sucrol 152

Sucrose, in cacao products 329

condensed milk 293

flavoring extracts 260, 264

foods and feeding stuffs 81-85

fruits and fruit products 17'.'

saccharine products 12!>, 134, 137, 138

tomato products 324

wines

380 INDEX

Sugar, as a coating and glazing substance, in coffees 333

house products 138

Sugars, in canned vegetables 186

cattle foods 109

distilled liquors 246

meat and meat products 278, 285

wheat flour 187

Sulphite-cellulose, in tanning materials 54

Sulphuric acid, in baking powders 346

mineral water 44, 50, 51

plants 32

soils 24

wines 238

Sulphur, in mustard 319

plants 32

Sulphurous acid 150

Sweetening substitutes, in fruits and fruit products 184

Tannin, in cloves and allspice 319

leathers 61

tanning materials 54

tea 336

wines 240

Tanning extracts 53

liquors 55

materials 53-57

raw and spent 56

Tartaric acid, free, in baking powders 344

wines 240

or combined in baking powders 343

total, in baking powders 343

fruits and fruit products 180

vinegars 257

wines 240

and tartrates in vinegars 257

Tartrazine 158

Tea 335-337

Thomas or basic slag 14-15

Tin, in foods _ 173

Titer test for fats and oils 302

Tobacco and tobacco extract 73-75

Tomato products 322

Tragacanth 360

Trillat Method for methyl alcohol in distilled liquors 246

Trowbridge and Francis Method for glycogen in meat 277

Turbidity, in potable water - 35

Turmeric \ 168

Turpentine 365

Ulsch-Street Method for nitric and ammoniacal nitrogen in fertilizers 10

INDEX 381

Unsaponifiable residue, in fats and oils 312

Vanilla extract and its substitutes 259

resins 260

Vanillin, in vanilla extract 259

Van Slyke Method for amino nitrogen in meat extracts 282

Villavecchia Test for sesame oil 314

Vinegars 253-258

Volatile matter, in soils 17

oil, in tea 336

Volhard Method for chlorin in plant ash 32

Water extract, acidity of, in wheat flour 187

in tea 335

industrial 49-51

irrigating 51-52

mineral 41-49

potable 35-41

Waters 35-52

Water-soluble material, in leathers 59

Waxes, in coffees 334

Wein Method for maltose 103

Wiley Method for melting point of fats and fatty acids 301

Wines 193-242

Winkler Method, as Modified by Drown and Hazen, for dissolved oxygen in water 40

Rideal and Stewart, for dissolved oxygen in water 40

Wintergreen extract 268

Winton Method for soluble solids in coffees 331

Ogden and Mitchell Method for nitrogen in non-volatile ether extract. . 317
Wolff Method for free or combined tartaric acid in baking powders 343

Yeasts and spores, in tomato pulp, etc 325

Zinc, in foods 175

arsenite 69

THE END

1*