TESTING MILK

ITS PKODUCTS

FARRINGTON AND WOLL

DP. S, M. BABCOCK,

INVENTOR OF THE BABCOCK MILK TEST,

TESTING MILK

AND ITS PRODUCTS

A MANUAL FOR DAIRY STUDENTS, CREAMERY- AND CHEESE FAC-
TORY OPERATORS, FOOD CHEMISTS, AND DAIRY FARMERS

BY

E. H. HARRINGTON and F. W. WOLL

Professor in Charge of Dairy School Asst. Prof, of Agr'l Cliemistry

Of tr|e University of Wiscoqsin

TWELFTH, REVISED AND ENLARGED EDITION

MADISON, WLS.

MENDOTA BOOK COMPANY
1901

AL.L, RIGHTS RESERVED

COI'YKIGHT, 1897, 18W AND 1901,

BY E. H. FARRINGTON AND F. W. WOLL

Add'l

(B^
GIFT

M. .1. CANTWEL.K, PRINTER.

Madison, Wis.

PREFACE TO FIRST EDITION.

The present volume is intended for the use of dairy students,
factory operators, daymen, food chemists, and others inter-
ested in the testing or analysis of milk and its products. The
subject has been largely treated in a popular manner; accuracy
and clearness of statement, and systematic arrangement of the
subject matter have, however, been constantly kept in mind.
The aim has been to make the presentation intelligible to
students with no further training than a common-school educa-
tion, but their work will naturally be greatly lightened by the
aid of an able teacher.

Complete directions for making tests of milk and other dairy
products are given ; difficulties which the beginner may meet
with are considered in detail, and suggestions offered for avoid-
ing them. It is expected that a factory operator or practical
dairyman, by exercising common sense and ordinary care, can
obtain sufficient knowledge of the subject through a study of
the various chapters of this book to make tests of milk, cream,
etc., even if he has had no previous experience in this line.

For the benefit of advanced dairy students who are some-
what familiar with chemistry and chemical operations, Chapter
XIV has been added giving detailed instruction for the com-
plete chemical analysis of milk and other dairy products. The
detection of preservatives and of artificial butter or filled cheese
has also been treated in this connection.

As the subject of milk testing is intimately connected with
the payment for the milk delivered at butter- and cheese fac-
tories, and with factory dividends, a chapter has been devoted
to a discussion of the various systems of factory book-keeping,
and tables greatly facilitating the work of the factory secretary
or book-keeper have been prepared and are included in the
Appendix.

JW78128O

iv Testing Milk and Its Products.

Acknowledgment is due to the following parties for the use
of electrotypes, viz : Creamery Pkg. Mfg. Co., Chicago, 111.;
Vermont Farm Machine Co., Bellows Falls, Vt; Elgin Mfg.
Co., Elgin, 111.; D. H. Burrell & Co., Little Falls, N. Y.; De
Laval Separator Co., New York City; Henry Tromner, Phila-
delphia, Pa.; Springer Torsion Balance Co., New York City;
J. H. Monrad, Winnetka, 111.; Borden & Selleck Co., Chicago,
111.; Dairymen's Supply Co., Philadelphia, Pa.; Bausch &
Lomb Opt. Co., Rochester, N. Y.; John W. Decker, Columbus,
Ohio, C. L. Fitch, Fort Atkinson, Wis., and the agricultural
experiment stations at New Haven, Conn., and Madison, Wis.

Madison, Wis., October 1, 1897.

PREFACE TO EIGHTH EDITION.

The first three editions of this book were disposed of in about
a year and the seventh edition was exhausted three years later.
Every year that passes brings some valuable contributions to
our knowledge of the subjects treated in the book and a fre-
quent revision of it is therefore desirable.

The present edition contains all the methods and descrip-
tions that have stood the test of actual use during the past few
years and the new information which has appeared since the
last revision of the book, has been carefully sifted and what
was deemed of sufficient importance has been incorporated in
such detail as the scope of the book permitted; many changes
and additions suggested by the experience of the authors have
also been introduced. In brief the book has been subjected to
a renewed, critical examination and revision. The general
adoption of it as a text book in American Dairy Schools, as well
as the favorable reception which it has been accorded by users
of Babcock testers and the dairy public in general is naturally
a source of gratification to the authors.

Madison, Wis., July 1, 1901.

TABLE OF CONTENTS.

PAGE.
Introduction 1

Chap. I. COMPOSITION OP MILK AND ITS PRODUCTS . . 11

Composition of milk: Water. Fat. Casein and albu-
men. Milk sugar (lactose). Ash. Other components.
Colostrum milk. Composition of milk products.

Chap. II. SAMPLING MILK 23

Sweet milk. Partially churned milk. Sour milk. Frozen
milk.

Chap. III. THE BABCOCK TEST— MILK 28

A. Directions for making the test: Sampling. Adding
acid. Mixing milk and acid. Whirling bottles. Adding
water. Measuring the fat.

B. Discussion of the details of the test:

1. Glassware. Test bottles. Pipettes. "Fool pipettes."
Acid measures. The Swedish acid bottle. Calibration of
glassware. Calibration with mercury. Calibration with
water. The Trowbridge method of calibration.

2. Centrifugal machines. Speed required for the com-
plete separation of the fat. Ascertaining the necessary
speed of testers. Hand testers. Power testers.

3. Sulfuric acid. Testing the strength of the acid. The
Swedish acid tester. The color of the fat column an index
to the strength of the acid used. Influence of temperature
on the separation of fat.

4. Water to be used in the Babcock test. Reservoir for
water.

5. Modifications of the Babcock test. The Russian milk
test. Bartlett's modification. Siegfeld's modification.
Bausch and Lomb centrifuge.

Chap. IV. THE BABCOCK TEST— CREAM 74

Measuring the cream. Cream-test bottles. The bulb-
necked cream bottle. The Winton cream bottle. Use of
milk test bottle. Use of 5 cc. pipette. Weighing the
cream.

vi Testing Milk and Its Products.

PAGE.

Chap. V. THE BABCOCK TEST FOR OTHER MILK PROD-
UCTS 85

Skim milk, butter milk, and whey. The double-necked
test bottle. The Wagner test bottle. The double-sized
skim milk bottle. Cheese. Condensed milk.
Chap. VI. THE LACTOMETER AND ITS APPLICATION . . 93

The Quevenne lactometer. Influence of temperature.
N. Y. Board of Health lactometer. Reading the lacto-
meter. Time of taking lactometer readings. Influence of
bi-chromate on lactometer reading. Calculation of milk
solids. Adulteration of milk. Legal standards. The
specific gravity of the milk solids. Calculation of extent
of adulteration: Skimming. Watering. Watering and
skimming.

Chap. VII. TESTING THE ACIDITY OF MILK AND CREAM 108

Cause of acidity in milk. Methods of testing acidity.
Manns' test. Devarda's acidimeter. The alkaline-tablet
test. Determination of acidity in sour cream. Spillman's
cylinder. Rapid estimation of the acidity of apparently
sweet milk and cream. Detecting boracic-acid preserva-
tives in milk. "Alkaline Tabs."

Chap. VIII. TESTING THE PURITY OF MILK 125

The Wisconsin curd test. The fermentation test. The
Monrad rennet test. The Marshall rennet test.

Chap. IX. TESTING MILK ON THE FARM 131

Variations in milk of single cows. Number of tests re-
quired during a period of lactation in testing cows. When
to test a cow. Gurler's method. Sampling milk of single
cows. Variations in herd milk. Influence of heavy grain
feeding on the quality of milk. Influence of pasture on
the quality of milk. Method of improving the quality of
milk.

Chap. X. COMPOSITE SAMPLES OF MILK 148

Methods of taking composite samples: a. Use of tin
dipper, b. Drip sample, c. Scovell sampling tube. d. The
equity milk sampler, e. One-third sample pipette. Pre-
servatives for composite samples. Fallacy of averaging
percentages.

Table of Contents. vii

PAGE.

Chap. XI. CREAM TESTING AT CREAM-GATHERING CREAM-
ERIES 165

The space system. The oil -test churn. The Babcock
test for cream. Sampling cream for composite testing.

Chap. XII. CALCULATION OF BUTTER- AND CHEESE YIELDS 176

A. Calculation of yield of butter: Butter fat test and
yield of butter. Variations in composition of butter.
Overrun of churn over test. Factors influencing the over-
run. Calculation of overrun. Overrun at gathered-cream
factories. Conversion factor for butter fat. Butter yield
from milk of different richness, a. Use of butter chart, b.
Use of overrun table.

B. Calculation of yield of cheese: a. From fat. b. From
solids not fat, and fat. c. From casein and fat.

Chap. XIII. CALCULATING DIVIDENDS 190

A. Calculating dividends at creameries: Proprietary
creameries. Co-operative creameries. Other systems of
payments. Paying for butter delivered. Relative-value
tables. Calculating dividends at factories receiving both
milk and cream.

B. Calculating dividends at cheese factories: Proprie-
tary factories. Co-operative factories.

Chap. XIV. CHEMICAL ANALYSIS OF MILK AND ITS PRO-
DUCTS 204

Milk. Cream. Skim milk, butter milk, whey. Con-
densed milk. Butter. A practical method of salt analy-
sis. Detection of "process" butter. Detection of artificial
butter. Reichert-Wollny method (Volatile acids). Cheese.
Detection of oleomargarine cheese ("Filled" cheese).

Tests for adulteration of milk and cream. Detection of
pasteurized milk or cream. Detection of preservatives in
dairy products.

Appendix 233

Table I. Composition of milk and its products.
Table II. State and city standards for dairy products.
Table III. Quevenne lactometer degrees corresponding
to the scale of the N. Y. Board of Health lactometers.

viii Testing Milk and Its Products.

PAGK.

Table IV. Value of 10° 9~1- for specific gravities from
1.019 to 1.0369.

Table V. Correction table for specific gravity of milk.

Table VI. Per cent, of solids not fat, corresponding to
0 to 6 per cent, of fat and lactometer readings of 26 to 36.

Directions for the use of tables VII, VIII, IX and XI.

Table VII. Pounds of fat in 1 to 10,000 pounds of milk
testing 3 to 5.85 per cent.

Table VIII. Pounds of fat in 1 to 1,000 Ibs. of cream
testing 12.0 to 50.0 per cent. fat.

Table IX. Amount due for butter fat, in dollars and
cents, at 12 to 25 cents per pound.

Table X. Relative-value tables.

Table XI. Butter chart, showing calculated yield of
butter, in pounds, from 1 to 10,000 pounds of milk testing
3.0 to 5.3 per cent, of fat.

Table XII. Overrun table, showing pounds of butter
from 100 pounds of milk.

Table XIII. Yield of cheese, corresponding to 2.5 to 6
per cent, of fat, with lactometer readings of 26 to 36.

Table XIV. Comparisons of Fahrenheit and Centigrade
(Celcius) thermometer scales.

Table XV. Comparison of metric and customary weights
and measures.

Suggestions regarding the organi/atiou of co-operative
creameries and cheese factories.

Constitution and by-laws for co-operative factory asso-
ciations.
Index 264

Testing Milk and Its Products*

INTRODUCTION.

The need of a rapid, accurate and inexpensive method
of determining the amount of butter fat in milk and other
dairy products became more and more apparent, in this
country and abroad, with the progress of the dairy in-
dustry, and especially with the growth of the factory
system of butter- and cheese making during the last few
decades. So long as each farmer made his own butter
and sold it to private customers or at the village grocery,
it was not a matter of much importance to others whether
the milk produced by his cows was rich or poor. But
as creameries and cheese factories multiplied, and farm-
ers in the dairy sections of our country became to a
large extent patrons of one or the other of these, a sys-
tem of equitable payment for the milk or cream delivered
became a vital question.

I. The creameries in existence in this country up to
within fifteen years were nearly all conducted on the
cream-gathering plan: the different patrons creamed
their milk by the gravity process, and the cream was
hauled to the creamery, usually twice or three times a
week, where it was then ripened and churned. The
patrons were paid periwc^of cream furnished 5 a creamery
inch is a quantity of cream which fills a can twelve inches
1

2 Testing Milk and Us Products.

in diameter, one inch high, or 113 cubic inches. This
quantity of cream was supposed to make a pound of but-
ter, but cream from different sources, or even from the
same sources at different times, varies greatly in butter-
producing capacity, as will be shown under the subject
of cream testing (2101). The system of paying for the
number of creamery inches delivered could not there-
fore long give satisfaction.

The proposition to take out a small portion, a pint or
half a pint, of the cream furnished by each patron, and
determine the amount of butter which these samples
would make on being churned in so-called test churns,
found but a very limited acceptance, on account of the
labor involved and the difficulty of producing a first-class
article from all the small batches of butter thus obtained.

2. The introduction of the so-called oil test churn in
creameries which followed the creamery-inch system,
marked a decided step in advance, and it soon came into
general use in gathered -cream factories (203). In this
test, glass tubes of about f inch internal diameter and
nine inches long, are filled with cream to a depth of five
inches, and the cream churned; the tubes are then placed
in hot water, and the column of melted butter formed at
the top is read off by means of a scale showing the num-
ber of pounds of butter per creamery inch corresponding
to different depths of melted butter. While the oil test
is capable of showing the difference between good and
poor cream, it can not make strictly accurate distinctions
between different grades of good and of poor cream2. As

1 Refers to paragraph numbers.

2 Wisconsin Experiment Station Bulletin 12.

Introduction. 3

a result, perfect justice cannot be done to different pat-
rons of creameries where payments for cream delivered
are made on the basis of this test.

3. In cheese factories, and since the introduction of the
centrifugal cream separator, in separator creameries, the
problem of just payment for the milk furnished by differ-
ent patrons was no less perplexing than in the case of
gathered- cream factories. By the pooling system gener-
ally adopted, each patron received payment in propor-
tion to the number of pounds of milk delivered, irre-
spective of its quality. Patrons delivering rich milk
naturally will not be satisfied with this system when they
find that their milk is richer than that of their neigh-
bor's. The temptation to fraudulently increase the
amount of milk delivered, by watering, or to lower its
quality by skimming, will furthermore prove too strong
for some patrons; the fact that it was difficult to prove
any fraud committed, from lack of a reliable and practi-
cal method of milk analysis, rendered this pooling system
still more objectionable.

4. As another instance in which the need of a simple
test for determining the fat content of different kinds of
milk was strongly felt, may be mentioned the case of pri-
vate dairymen and breeders of dairy cattle, who desired
to ascertain the butter-producing capacities of the indi-
vidual cows in their herds. The only manner in which
this could be done, was by the cumbersome method of
trial churnings: by saving the milk of the cow to be
tested, for a day or a week, and churning separately the
cream obtained. This requires a large amount of work
when a number of cows are to be tested, and can not

4 Testing Milk and Its Products.

therefore be done except in comparatively few cases,
with cows of great excellence or by farmers having
abundant hired help.

5. Introduction of milk tests. The first method which
fulfilled all reasonable demands of a practical and reliable
milk and cream test was the Babcock test, invented by
Dr. S. M. Babcock, chemist to the Wisconsin experiment
station. A description of the test was first published in
July, 1890, as bulletin No. 24 of Wisconsin experiment
station, entitled: A neic method for the estimation of fat in
milk, especially adapted to creameries and cheese factories.
This test, which is now known and adopted in all parts
of the world where dairying is an important industry,
was not, however, the first method proposed for this pur-
pose which could be successfully operated outside of
chemical laboratories. It was preceded by a number of
different methods, the first one published in this country
being Short's method, invented by Mr. P. G. Short and
described in bulletin No. 16 of Wisconsin experiment
station (July, 1888).

6. Short's test. In this ingenious method, a certain
quantity of milk (20 cc.1) was boiled with an alkali solu-
tion and afterwards with a mixture of sulfuric and acetic
acids; a layer of insoluble fatty acids separated on top
of the liquid and was brought into the graduated neck
of the test bottles by addition of hot water; the reading
gave the per cent, of fat in the sample of milk tested.

Short's method did not find very wide application,
both because it was rather lengthy and its manipulations
somewhat difficult for non-chemists, and because several

i See 48, footnote.

Introduction. 5

other methods were published shortly after it had been
given to the public.

7. Other milk tests. Of these may be mentioned, be-
sides the Babcock test already spoken of, the Failyer and
Willard method,1 Parson's method,2 Cochran's test,3 the
Patrick or Iowa station test,4 and the Beimling (Leif-
mann and Beam) test.5 Of foreign methods published at
about the same time, or previously, the Lactocrite,0 Lie-
bermann's method,7 the Schmid,8 Thorner,9 Nahm,10 and
Kose- Gottlieb11 methods may be noted.

8. All these tests were similar in principle, the solids
not fat of the milk being in all cases dissolved by the
action of one or more chemicals, and the fat either meas-
ured as such in a narrow graduated tube, or brought into
solution with ether, gasoline, etc., and a portion thereof
weighed on evaporation of the solvent. While this prin-
ciple is an old one, having been employed in chemical
laboratories for many years past, its adaptation to prac-
tical conditions, and the details as to apparatus and chem-
icals used were of course new and different in each case.
The American tests given were adopted to a limited
extent within the states in which they were originated

1 Kansas experiment station report, 1888, p. 149.

2 N. H. experiment station report, 1888, p. 69.

3 Journal of Anal. Chem., Ill (1889), p. 381.

4 la. exp. sta., bull. No. 8, February, 1890; Iowa Homestead, June 14, 1889.

5 Vermont exp. sta., bull. No. 21, September, 1890. For description of
these and other volumetric methods of milk analysis, see Wiley, Agricul-
tural Analysis, Vol. Ill, p. 490 et seq; Wing, Milk and its Products, p. 33
et seq, and Snyder, Chemistry of Dairying, pp. 112-113.

6 Analyst, 1887, p. 6.

7 Fresenius' Zeitschr., 22, 383.

8 Ibid., 27, 464.

9 Chem. Centralbl., 1892, 429.

10 Milchzeitung, 1894, No. 35; 1897, No. 50.

11 Landw. Vers. Stat., 40, 1.

6 Testing Milk and Its Products.

and even outside of them, as in case of the Short, Pat-
rick and Be i ml ing methods. The Babcock test soon,
however, nearly everywhere replaced the different meth-
ods mentioned, and during the past eight or ten years it
has been in practically exclusive use in creameries and
cheese factories in this country, where payments are
made on the basis of the quality of the milk delivered,
as well as in the routine work in experiment station
laboratories, and among milk inspectors and private
dairymen.

9. The Babcock Test. An examination of the causes
of the present general adoption of the Babcock test will
show the strong points of the test, and the requirements
made of a practical milk test. The main causes why this
test has replaced all competitors are doubtless to be
sought in its simplicity and its cheapness. Its manipu-
lations are few and readily learned, and it is cheap, both
in first cost and as regards running expenses.

The test is furthermore speedy, accurate,1 and easily
applicable to practical conditions, and in the opinion of
the writers it is the very best milk test at our disposal.

The method is applicable, besides to whole milk, to
cream, skim milk, butter milk, whey, condensed milk,
and (if a small scale for weighing out the sample is avail-
able) to cheese.

With all its advantages, the Babcock milk test is not
in every respect an ideal test. The handling of the very
corrosive sulfuric acid requires constant care and atten-

i For a summary of comparative analyses made by the Babcock test
and gravimetric analysis up to 181)2, see Hoard's Dairyman, Oct. 7, 1892, p.
2.560; alKoSrhrott-Fierhl), Milchzeitnng, 1890, p. 183 etseq.

Introduction.

tion; the speed of the tester, the strength of the acid, the
temperature of the milk to be tested, and other points,
always require watching, lest the results obtained be too
low or otherwise unsatisfactory. In the hands of careful
operators the test can, however, always be relied upon
to give most satisfactory results.

10. Foreign methods. In European countries four
practical milk and cream tests, besides the Babcock test,
are in use at the present time, viz.: Gerber's acid-
butyrometer, the lactocrite, DeLavaVs butyrometer, and
Fjord's centrifugal cream test.1

Of these, the last test
given has never, to our
knowledge, been intro-
duced into this country,
and the first three only on
a small scale.

11. The Gerber method"
(fig. 1) is essentially the
old Beimling method (7),
worked out independently
by the Swiss chemist, Dr.
N. Gerber. In this test
sulfuric acid of the same
strength is used as in the

BabcOCk test, and a Small FlG- K The Gerber acid-butyrometer.

quantity of amyl alcohol is added. The amyl alcohol
facilitates the separation of the fat, but introduces

1 The Lister-Babcock milk test advertised in English papers and known
as such in England, is the regular Babcock test, to which the English man-
ufacturers have prefixed their names; the same applies to the Ahlborn-
Babcock method and the Krugmann-Babcock method.

2 Gerber, Die praktische Milchpriifung 7th edition, 1900.

s

Testing Milk and Its Products.

a source of error which may become serious, and espe-
cially so, where the results obtained with a new lot of
amyl alcohol can not be compared with gravimetric
analysis or with tests made with amyl alcohol known to
give correct results. This method is, however, exten-
sively used in several European countries, having there
practically replaced the Babcock test or been adopted in
preference to it.

12. The Lactorite was one of the earliest practical
milk tests introduced. It was invented by De Laval in
188G. The acids used in this test are lactic acid (origi-
nally, acetic acid) with a mixture of hydrochloric and
sul f uric acids. This test is now but rarely met with,
even in Europe, having been largely replaced by the
following method.

13. In the De Laval butyrometsr (fig. 2) the same acid
is used as in the Babcock test, but the tubes employed and
the manipulations of the method differ materially from

Fi«. 2. DeLaval's butyrometer.

Introduction.

this test; a smaller sample of milk is taken (only 2 cc.)
and a correspondingly small quantity of acid used. Where
a large number of milk samples are tested every day,
as is the case, for instance, in European milk control sta-
tions, the butyrorneter may be preferable to the Babcock
test; but it requires more skill of the operator and does
not work satisfactorily in case of sour, loppered, or
partially churned milk. The machines placed on the
market both by Dr. Gerber and the De Laval Company
are more expensive than the Babcock testers sold in this
country; the DeLaval test requires a high speed, 5-6000
revolutions per minute; and therefore places greater de-
mands for solidity in the machine than does the Babcock
test.

14. Fjord's centrifugal cream tester1 (fig. 3) is exten-
sively used in Denmark and is mentioned in this connec-
tion as it furnishes, as a
rule, a reliable method for
comparing the quality of
different lots of milk. The
method was published in
1878, by the late N. J. Fj ord,
director of the state experi-
ment station in Copenhagen,
through whose exertions
tester. and on whose authority it

was introduced into Danish creameries in the middle of the
eighties. No chemicals are added in this test, the milk
being simply placed in glass tubes, seven inches long
and about two-thirds of an inch in diameter, and whirled

ugal cream

i State Danish experiment station, Copenhagen, sixth and ninth re-
ports, 1885-7.

10 Testing Milk and Its Products.

for twenty minutes at a rate of 2000 revolutions per
minute at 55° C (131° F.). The reading of the cream
layer thus obtained gives the per cent, of cream, and
not of butter fat, in the sample tested. One hundred
and nine-two samples of milk can be tested simultan-
eously. Within the limits of normal Danish herd milk,
the results obtained correspond to the percents of fat
present in the samples, one per cent, of cream being
equal to about 0.7 per cent, of fat; outside of these
limits the test is, however, unreliable, especially in case
of very rich milk and strippers' milk. Only sweet milk
can be tested by this method. The recent introduction
of milk tests proper into Denmark, like the Gerber, Bab-
cock and De Laval tests may, however, in time force the
Fjord cream test out of Danish creameries, for similar
reasons that relegated to obscurity the gravity cream
tests (creamometers).1

i Among foreign milk tests in use abroad should also be mentioned the
Wnllnji Refractomcter, which, in the hands of a trained chemist, is better
adapted for use where n very large number of samples are to be tested at
a time, than any other milk test available.

CHAPTER I.
COMPOSITION OF MILK AND ITS PRODUCTS.

Before taking up the discussion of the Babcock niilk
test, a brief description of the chemistry of milk and its
products is given, so that the student may understand
what are the components of dairy products, and the rela-
tion of these to each other. Only such points as have a
direct bearing on the subject of milk testing and the use
of milk tests in butter and cheese factories or private
dairies will be treated in this chapter, and the reader is
referred to standard works on dairying for more detailed
information in regard to the composition of dairy pro-
ducts.

15. Composition of milk. Milk is composed of the fol-
lowing substances: water, fat, casein, albumen, milk sugar,
and ash. A few other substances are present in small
quantities, but they are hardly of any practical impor-
tance and will not be considered here. The components
of the milk less the water are known collectively as milk
solids or total solids, and the total solids less the fat, i. e.,
casein, albumen, milk sugar, and ash, are often spoken
of as solids not fat or the non-fatty milk solids. The milk
serum includes all components of the milk less the fat;
the serum solids are therefore another name for the solids
not fat; when given, they are, however, generally calcu-
lated to per cent, of milk serum, not of milk. If, e. g.,
a sample of milk contains nine per cent, of solids not fat,

12 Testing Milk and Its Product*.

and three per cent, of fat, the niilk serum will make up
97 per cent, of the milk, and the serum solids, .y97=9.28
per cent, of the milk serum.

16. Water. The amount of water contained in cows'
milk ranges from 82 to 90 per cent. Normal cows' milk
will not as a rule contain more than 88 per cent, of water,
nor less than 84 per cent. In states where there are laws
regulating the sale of milk, as is the case in eighteen
states in the Union (see Appendix}, the maximum limit
for water in milJC in all instances but one (South Carolina)
is 88 per cent. ; the state mentioned allows 88.5 per cent,
of water in milk offered for sale within her borders. The
effect of fraudulently increasing the water content of
milk by watering is considered under Adulteration of
Milk (118).

17. Fat. The fat in milk is not in solution, but sus-
pended as very minute globules, which form an emulsion
with the milk serum; the globules are present in immense
numbers, viz., on the average about one hundred million
in a single drop of milk; a quart of milk will contain
about two thousand billions of fat globules, a number
written with thirteen ligures. The size of the globules
in the milk from the same cows varies according to the
stage of the period of lactation, the globules being largest
at the beginning of the lactation period, and gradually
decreasing in size with its progress. Different breeds of
cows have fat globules of different average sizes; the
Channel Island cows are thus noted for the relatively
large fat globules of their milk, while the Lowland
breeds, the Ayrshire, and other breeds have uniformly
smaller globules. The diameter of average sized fat

Composition of Milk and Its Products. 13

globules in fresh milkers is about 0.004 millimeter, or
one-six-thousandth of an inch; that is, it takes about six
thousand such globules placed side by side to cover one
inch in length. The globules in any sample of milk
vary greatly in size; the largest globules are recovered
in the cream when the milk is set or run through a cream
separator, and the smallest ones remain in the skim milk;
thoroughly skimmed separator skim milk will contain
only a small number of very minute fat globules.

Milk fut is composed of so-called glycerides of the fatty
acids, i. e., compounds of the latter with glycerin; some
of the fatty acids are insoluble in water, viz., palmitic,
stearic, and oleic acids, while others are soluble and vol-
atile, the chief ones among the latter being butyric, cap-
rylic, and caproic acids. The glycerides of the insoluble
fatty acids make up about 92 per cent, of the pure milk
fat; about 8 per cent, of the glycerides of volatile fatty
acids are therefore found in natural milk- (and butter-)
fat. The distinction between natural and artificial but-
ter lies mainly in this point, since artificial butter (but-
terine, oleomargerine) as well as other solid animal fats
contain only a very small quantity of volatile fatty acids.
The glycerides of the volatile fatty acids are unstable
compounds, easily decomposed through the action of
bacteria or light; the volatile fatty acids thus set free,
principally butyric acid, are the cause of the unpleasant
odor met with in rancid butter.

Cows7 milk generally contains between three and six
per cent, of fat; in American milk we find on the
average toward four per cent, of fat. The milk from
single cows in perfect health will occasionally go below

14 Testing Milk and Its Products.

or above the limits given, but the mixed milk from a
whole herd rarely falls outside of these limits. The
legal standard for fat in milk in most states of the Union
is 3 per cent; Rhode Island allows milk containing 2.5
per cent, of fat to be sold as pure, while Georgia and
Minnesota require it to contain 3.5 per cent., and Massa-
chussetts 3.7 per cent, (in the months of May and June;
see Appendix, Table II. )

18. Casein and albumen. These belong to the so-called
nitrogenous substances, distinguished from the other com-
ponents of the milk by the fact that they contain the
element nitrogen. Another name is albuminoids or pro-
tein compounds. Casein is precipitated by rennet in the
presence of soluble calcium salts, and by dilute acids and
certain chemicals; albumen is not acted upon by these
agents, but is coagulated by heat, a temperature of 170° F.
being sufficient to effect a perfect coagulation. The
casein, with fat and water, form the main components of
nearly all kinds of cheese. In the manufacture of ched-
dar and most other solid cheeses, the casein is coagulated
by rennet, and the curd thus formed holds fat and whey
mechanically, the latter containing in solution small
quantities of non-fatty milk solids. The albumen goes
into the whey, and in some countries is also made into
cheese by evaporating the whey with constant stirring;
whole milk of cows or goats is often added and incor-
porated into such cheese (primost, gjedost).

Casein is present in milk partly in solution, in the
same way as milk sugar, soluble ash -materials and albu-
men, and partly in suspension, in an extremely fine col-
loidal condition, mixed or combined with insoluble

Composition of Milk and Its Products. 15

calcium phosphates. The casein and calcium phosphates
in suspension in milk may be retained on a filter made
of porous clay (so-called Chamberland filters] .

About 80 per cent, of the nitrogenous compounds of
normal cows' milk are made up of casein; the rest is
largely albumen. If the amount of casein in milk be
determined by precipitation with rennet or dilute acids,
and the albumen by boiling the filtrate from the casein
precipitate, it will be found that the sum of these two
compounds does not make up the total quantity of nitro-
genous constituents in the milk. The small remaining
portion (about five per cent, of the total nitrogenous
constituents) has been called by various authors, globu-
lin, albumose, henii-albumose, nuclein, nucleon, proteose,
etc. The nitrogenous constituents of milk are very un-
stable compounds, and their study presents many and
great difficulties; as a result we find that no two scien-
tists who have made a special study of these compounds
agree as to their properties, aside from those of casein
and albumen, or their relation to the nitrogenous sub-
stances found elsewhere in the animal body. For our
purpose we may, however, consider the nitrogen com-
pounds of milk as made up of casein and albumen, and
the term casein and albumen, as used in this book, is
meant to include the total nitrogenous constituents of
milk, obtained by multiplying the total nitrogen content
of the milk by 6. 25. 1

iThe factor 6.25 is generally used for obtaining the casein and albumen
from the total nitrogen in the milk, although 6.37 would be more correct,
since these substances, according to our best authorities, contain on the
average 15.7 per cent, of nitrogen ( —^ = 6.37 )

16 Testing. Milk and Its Products.

The quantity of casein in normal cows' milk will vary
from 2 to 4 per cent., and of albumen, from .5 to .8 per
cent. The total content of casein and albumen ranges
between 2.5 and 4.6 per cent., the average being about
3.4 per cent. Milk with a low fat content will contain
more casein and albumen than fat, while the reverse is
generally true in case of milk containing more than 3.5
per cent of fat.

19. Milk sugar or lactose belongs to the group of organic
compounds known as carbohydrates. It is a commercial
product manufactured from whey and is obtained in this
process as pale white crystals, of less sweet taste and
less soluble in water than ordinary sugar (cane sugar,
sucrose). About 70 per cent, of the solids in the whey, and
33 per cent, of the milk solids, are composed of milk sugar.

When milk is left standing for some time, viz., from
one to several days, according to the temperature of the
surrounding medium, it will turn sour and soon become
thick and loppered. This change in the composition
and the appearance of the milk is brought about through
the action of acid-forming bacteria on the milk sugar;
these are present in ordinary milk in immense numbers,
and under favorable conditions of temperature multiply
rapidly, feeding on the milk sugar as they grow, and
decomposing it into lactic acid. When this change alone
occurs, there is not necessarily a loss in the nutritive
value of the milk, since milk sugar breaks up directly into
lactic acid ; this is shown by the following chemical formula:

C12H22O, j. H2O (lactose) = 4 C3H6O3 (lactic acid).1

lOne molecule of milk sugar is composed of 12 atoms of carbon (C),
22 atoms of hydrogen (H), 11 atoms of oxygen (O), and one molecule of
water (H2O). In the same way, the lactic-acid molecule consists of 3 atoms
of carbon, 6 atoms of hydrogen, and 3 atoms of oxygen.

Composition of Milk and Its Products. 17

Ordinarily the souring of milk is, however, more
complicated, and other organic bodies, like butyric acid,
alcohol, etc., and gases like carbonic acid are formed,
resulting in a loss in the feeding value of the milk.
While sour milk may therefore contain a somewhat
smaller proportion of food elements than sweet milk, the
feeding of it to farm animals, especially pigs, will gen-
erally produce better results than is obtained in feeding
similar milk in a sweet condition. The cause of this may
lie in the stimulating effect of the lactic acid of sour
milk on the appetites of the animals, or in its aiding
digestion by increasing the acidity of the stomach juices.

That the souring of milk is due to the activities of
bacteria present therein is shown clearly by the fact that
sterile milk, i. e., milk in which all germ life has been
killed, will remain sweet for any length of time when
kept free from infection.

The amount of milk sugar found in normal cows' milk
varies from 3.5 to 6 per cent., the average content being
about 5 per cent. ; in sour milk this content is decreased
to toward 4 per cent.

20. Ash. The ash or mineral substances of milk are
largely composed of chlorids and phosphates of sodium,
potassium, magnesium and calcium; iron oxid and sul-
furic and citric acids are also present in small quantities
among the normal mineral milk constituents. The
amount of the different bases and acids found in milk
ash have been determined by a number of chemists; the
average figures obtained are given in the following table,
calculated per 100 parts of milk (containing .75 per

cent of ash) and per 100 parts of milk ash.
2

18 Testing Mm and Its Products.

Mineral Components of Milk.

In per cent, of Milk. In per cent, of Ash.

Potassium oxid (K2O) 19 per ct. 25.64 per ct.

Sodium oxid (Na2O) 09 12.45

Lime(CaO) 18 24.58

Magnesia (MgO) 02 3.09

Iron oxid (Fe2O3) 002 .34

Phosphoric anhydrid (P2O5). .16 21.24

Chlorin (Cl) .12 16.34

.762 per ct. 103.68 per ct.
Less oxygen, corresponding to

chlorin... . .012 3.68

.75 perct. 100.00 per ct.

The combinations in which the preceding bases and
acids are contained in the milk are not known with cer-
tainty. According to Soldner, 36 to 56 per cent, of the
phosphoric acid found in milk, and from 53 to 72 per
cent, of the lime, are present in suspension in th*i milk
as di- and tri-calcium phosphates, and may be filtered
out by means of Chamberland filters (18), or by long
continued centrifuging (Babcock1), The rest of the ash
constituents are dissolved in the milk serum.

The ash content of normal cows' milk varies but little,
as a rule only between .6 and .9 per cent., with an
average of .7 per cent. Milk with a high fat content
generally contains about .8 per cent, of ash; strippers'
milk always has a high ash content, at times even ex-
ceeding one per cent. Ordinarily, the mineral constitu-
ents are, however, the components of milk least liable
to variation.

21. Other Components. Besides the milk constituents
enumerated and described in the preceding pages, nor-

1 Wis. Experiment Station, twelfth report, p. 93.

Composition of Milk and Its Products. 19

mal niilk contains a number of substances which are
present in but small quantities and have only scientific
interest, such as the milk gases (carbonic acid, oxygen,
nitrogen), citric acid, lecithin, cholesterin, urea, hypo-
xanthin, lactochrome, etc.

22. Average Composition. The average percentage com-
position of cows' milk will be seen from table I in the
Appendix. The following statement shows the limits
within which the components of normal American cows'
milk are likely to come:

Minimum. Maximum. Average.

Water 82.0 per ct. 90.0 per ct. 87.4 per ct.

Fat 2.5 7.8 3.5

Casein and albumen.. 2.5 4.6 3.4

Milk sugar 3.5 6.0 5.0

Ash 6 .9 .7

23. Colostrum Milk. The liquid secreted directly after
parturition is known as colostrum milk or biestings. It
is a thick, yellowish, viscous liquid; its high content of
albumen and ash is characteristic, and also its low con-
tent of milk sugar. Owing to the large quantity of
albumen which colostrum contains, it will coagulate on
being heated toward the boiling point. In the course of
four to five days the secretion of the udder gradually
changes from colostrum to normal milk; the milk is con-
sidered fit for direct consumption or for the manufacture
of cheese and butter, when it does not coagulate on boil-
ing and is of normal appearance as regards color, taste,
and other properties. For composition of colostrum
milk, see Appendix.

24. Composition of milk products. In addition to its
use for direct consumption, milk is the raw material from

20 Testing Milk and Its Products.

which cream, butter, cheese, and condensed milk are
obtained.

When milk is left standing for some time or subjected
to centrifugal force, it will separate into two distinct
parts, cream and skim milk. The proportion of each part
which is obtained and their chemical composition will de-
pend on the method by which the separation is effected; in
the so-called gravity process where the cream is separated
on standing — either in shallow pans in the air, or in deep
cans, submerged in cold water — a less complete separa-
tion is reached, less skim milk being obtained and this
being richer in fat than when the separation takes place
through the action of centrifugal force.

In modern creameries the milk is now generally skim-
med by means of cream separators. Separator cream will
contain from 15 to 50 per cent, of fat, according to the
adjustment of the separator and of the milk supply; ordi-
narily it contains about 25 per ct. of fat. Cream of aver-
age quality, in addition to the fat content given, consists
of about 66 per ct. of water, 3.8 per ct. casein and albu-
men, 4.3 per ct. milk sugar, and .5 per ct. ash.

The skim milk is made up of the milk serum (15) and a
small amount of fat, viz., toward .4 per ct. when obtained
by the gravity process, and less than .2 per ct. in the
case of separator skim milk. Milk set in shallow pans
in the air, or in deep cans in water above 60° F., will
give skim milk containing one-half to over one per ct. of
fat. Skim milk is used as a food for young farm animals
or as human food, and in this country in exceptional
cases, for the manufacture of cheese.

25. Cream is used for the manufacture of butter or for
direct consumption. In the former case a certain amount

Composition of Milk and Its Products. 21

of acidity is generally allowed to develop therein pre-
vious to the churning process. This secures a more
complete churning and produces peculiar flavors in the
butter, without which it would seem insipid to the ma-
jority of people in this country. Nearly all American
butter is salted before being placed on the market. Salt
is a preservative and for a limited length of time pre-
vents butter from spoiling. Unsalted butter made from
sweet cream is a common food article in Southern and
Middle Europe, but only an insignificant amount is man-
ufactured and consumed in America; salted butter made
in Europe also contains considerably less salt than Amer-
ican butter (see Appendix). Butter contains all the fat
of the cream but a small portion which goes into the
butter milk, and a small unavoidable mechanical loss in-
cident to the handling of the products. Butter should
contain at least 80 per ct. of fat, and ordinarily contains
about 83 per ct. ; besides this amount of fat, butter is gen-
erally composed of, water about 13 per ct., curd and
milk sugar 1 per ct., and salt 3 per ct.

Butter milk is similar to skim milk in composition, but
varies much more than this product, according to the
acidity, temperature, and thickness of the cream, and
other churning factors. It contains about 9 per ct. of
solids, viz., milk sugar (and lactic acid) 4 per ct., casein
and albumen 4 per ct., fat .3 per ct., and ash .7 per ct.

26. The quantities of butter and by-products obtained
in the manufacture of butter are as follows: 1000 Ibs. of
milk of average quality will give about 850 Ibs. of skim
milk and 145 Ibs. of cream (separator slime and mechan-
ical loss, 5 Ibs. ) ; this amount of cream will make about
42 Ibs. of butter and 100 Ibs. of butter milk (mechanical
loss, 3 Ibs.).

22 Testing Milk and Its Products.

27. In the manufacture of American clieddar cheese,
whole milk is heated to about 86° F., and a small
amount of rennet extract is added, which coagulates the
casein; the albumen of the milk is not precipitated by
rennet and remains in solution (18). " Green" cheese,
as taken from the press, is made up, roughly speaking,
of 37 per ct. of water, 34 per ct. of fat, 24 per ct, of
albuminoids (nearly all casein), and about 5 per ct. of
milk sugar, lactic acid, and ash. In the curing of cheese
there is some drying off, but the main changes occur in
the breaking up of the firm curd into soluble and digest-
ible nitrogenous compounds, peptons, amids, etc.

Whey is the by-product obtained in the manufacture
of cheese. It consists of water and less than 7 per ct. ol
solids; of the latter about 5 per ct. is milk sugar, .8 per
ct. albumen, .6 per ct. ash, and .3 per ct. fat. Whey is
generally used for feeding farm animals; it is the raw-
product from which milk sugar and whey cheese are made.

28. Condensed milk is manufactured from whole milk
or from partially skimmed milk. In many brands a large
quantity of sugar (33 per ct. or more) is added to the
condensed milk in the process of manufacture so as to
secure perfect keeping quality in the product. Other
brands to which no sugar has been added are, however,
on the market, and in case of such brands the relation
between the various solid constituents of the condensed
milk will be essentially the same as that between the
constituents of milk solids. Condensed milk should con-
tain at least 10 per ct. of fat, and must be free from pre-
servatives and all other foreign substances (except sugar).

Tables are given in the Appendix showing the average
composition of the various milk products.

CHAPTEE II.
SAHPLING fllLK.

29. The butter fat in inilk is not in solution, like sugar
dissolved in water, but the minute fat globules or drops,
in which form it occurs, are held in suspension in the
milk serum (17). Being lighter than the serum, the fat
globules have a tendency to rise to the surface of the milk.
If, therefore, a sample of milk is left standing for even
a short time, the upper layer will contain more fat than
the lower portion. This fact should always be borne in
mind when milk is sampled. The rapidity with which
fat rises in milk can be easily demonstrated by leaving a
quantity of sweet milk undisturbed in a cylinder or a
milk can for a few minutes, and testing separately the
top, middle and bottom layer of this milk.

The amount of mixing necessary to evenly distribute
the constituents of milk throughout its mass may be as-
certained by adding a few drops of cheese color to a
quart of ~ milk. The yellow streaks through the milk
will be noticed until it has been poured several times
from one vessel to another, when the milk will have a
uniform pale yellow color. Stiring with a stick or a
dipper will not produce an even mixture so quickly or
so completely as pouring the milk a few times from one
vessel to another; in sampling milk for testing it should
always be mixed by pouring, just before the milk is
measured into the bottle; if several tests are made of a
sample, the milk should be poured before each sampling.

24 Testing Milk and Its Products.

30. Partially churned milk. A second difficulty some
times met with in sampling whole milk arises from the
fact that a part of the butter fat may be separated in the
form of small butter granules, by too zealous mixing or
by reckless shaking in preparing the sample for testing.
This will happen most readily in case of milk from fresh
cows or with milk containing exceptionally large fat
globules. When some of the butter granules are thus
churned out, they quickly rise to the surface of the
milk after pouring and cannot again be incorporated in
the milk by simple mixing; it is, therefore, impossible
to obtain a fair sample of such milk for testing without
taking special measures which will be explained in the
following. The granules of butter may be so small as to
pass into the pipette with the milk and the quantity
measured thus contain a fair proportion of them, but
they will be found sticking to the inside of the pipette
when this is emptied, and thus fail to be carried into the
test bottle with the milk.

A similar partial churning of the milk will sometimes
take place in the transportation cans. When such milk
is received at the factory, the butter granules are caught
by the strainer cloth through which the milk is poured,
and are thus lost both to the factory and to the farmer.
This separated fat cannot be put into the cream or added
to the granular butter, without running the risk of mak-
ing mottled butter, and it will not enter into the sample
of milk taken for testing purposes.

When milk samples are sent by mail or express in
sni all* bottles, or carried to the place of testing, they
often arrive with lumps of butter floating in the milk or

Sampling Milk. 25

sticking to the glass. This churning of the milk can be
easily prevented by completely filling the bottle or the
can. If there is no space left for the milk in which to
splash around, the fat will not be churned out in transit.

31. Approximately accurate results may generally be
obtained with a partially churned sample of milk, if a
teaspoonful of ether be added to it. After adding the
ether, cork the bottle and shake it until the lumps of
butter are dissolved. This ether solution of the butter
will mix with the milk, and from the mixture a uniform
sample may generally be taken without difficulty. The
dilution of milk by the ether introduces an error in the
testing, and only the smallest quantity of ether necessary
to dissolve the lumps of butter should be used. If de-
sired, a definite quantity of ether, say five per cent, of
the volume of the sample of milk to be tested, may be
added; in such cases the result of the test must be in-
creased by the per cent, of ether added.

EXAMPLE. — To a 4-oz. sample (120 cc.) of partially churned
milk, 5 per cent., or 6 cc., of common ether are added: the mix-
ture gives an average test of 4.2 per cent. The test must be in-
creased by j£0 X 4.2 — .21, and the original milk therefore con-
tained 4.2-f.21=4.41 per cent, of fat.

Instead of adding ether to partially churned samples,
the milk may be heated to about 110° F. for about ten
minutes, so as to melt the butter granules; the sample is
now shaken vigorously until a uniform mixture of milk
and melted butter is obtained, and a pipetteful then
quickly drawn from the sample.

32. Sampling sour milk. When milk becomes sour, the
casein is coagulated and the mechanical condition of the

26 Testing Milk and Its Products.

milk thereby changed so as to render difficult a proper
sampling. The butter fat is not, however, changed in
the process of souring; this has been shown by one of us,
in a series of tests which were measured from one sample
of sweet milk into six test bottles.

A test of the milk in one of these test bottles was made
every month for six months, and approximately the same
amount of fat was obtained in the tests throughout the
series, as was found originally in the milk when tested
in a sweet condition.1 If the milk is in condition to be
sampled, its souring does not therefore interfere with its
being tested by the Babcock test or with the accuracy of
the results obtained.

In order to facilitate the sampling of sour or loppered
milk, some chemical may be added which will re-dissolve
the coagulated casein and produce a uniform mixture that
can be readily measured with a pipette. Any alkali
(powdered potash or soda, or liquid ammonia) will pro-
duce this effect. Only a very small quantity of powdered
alkali is necessary for this purpose. The complete action
of the alkali on sour milk requires a little time, and the
operator should not try to hasten the solution by adding
too much alkali. An excess of alkali will often cause
such a violent action of the sulfuric acid on the milk to
which the acid is added (on account of the heat generated
or the presence of carbonates in the alkali) that the mix-
ture will be thrown out of the neck of the test bottle when
this is shaken in mixing the milk and the acid (37).
When powdered alkali is added to the milk, it should be

1 See Hoard's Dairyman, April 8, 1892. The same holds true for cream,
as shown by Winton (U. S. Dept. Agr., Div. of Chemistry, bull. 43, p. 112).

Sampling Milk. 27

allowed to stand for a while, with frequent stirring, until
the curd is all dissolved and an even translucent liquid
is obtained. Such milk may become dark-colored by
the action of the alkali, but this color does not interfere
with the accuracy of the test.

Instead of powdered soda or potash, these substances
dissolved in water (soda or potash lye), or strong am-
monia water, may be used for the purpose of dissolving
the coagulated casein in a sample of sour milk. In this
case, a definite proportion of alkali solution must, how-
ever, be taken, 5 per cent, of the volume of milk being
usually sufficient, and the results obtained are increased
accordingly. (See example cited on p. 25.)

33. Sampling frozen milk. When milk freezes, it sep-
arates into two distinct portions: Milk crystals, largely
made up of water, with a small admixture of fat and
other solids, and a liquid portion, containing nearly all
the solids of the milk. In sampling frozen milk it is
therefore essential that both the liquid and the frozen
part be warmed and mixed thoroughly by pouring gently
back and forth from one vessel into another; the sample
is then taken and the test proceeded with in the ordinary
manner (36).

CHAPTEE III.
THE BABCOCK TEST.

34. The Babcock test is founded on the fact that strong
sulfuric acid will dissolve all non-fatty solid constituents

of milk and other
dairy products, and
will set free the fat.
This will separate on
standing, but to effect
a speedy and complete
separation, the bottles
holding the mixture
of milk and acid are
placed in a centrifugal
machine, a so-called
tester, and whirled for
five minutes ; hot
water is then added so
as to bring the liquid
fat into the graduated
neck of the test bot-
tles, and after a re-
peated whirling, the
length of the column
of fat is read off, show-

P,o 4 The first Babcoc* tester maae. jng ^ per ^ fflf ^

contained in the sample tested.

The Eabcock Test. 29

Sulfuric acid is preferable to other strong mineral
acids for the purpose mentioned, on account of its affinity
to water; when mixed with milk, the mixture heats
greatly, thus keeping the fat liquid without the applica-
tion of artificial heat and rendering possible a distinct
reading of the column of fat brought into the neck of the
test bottles.

So far as is known, any kind of milk can be tested by
the Babcock test. Breed, period of lactation, quality or
age of the milk is of no importance in using this method,
so long as a fair sample of the milk can be secured. In
case of samples of milk or other dairy products rich in
solids it requires a little more effort to obtain a thorough
mixture with the acid than with dairy products low in
solids, like skim milk or whey, which may be readily
mixed with the acid.

A — DIRECTIONS FOR MAKING THE TEST.

35. The various steps in the manipulation of the Bab-
cock test are discussed in the following pages; attention
is drawn to the difficulties which the beginner and others
may encounter in the use of the test, and the necessary
precautions to be observed in order to obtain accurate
and satisfactory results are explained in detail. The
effort has been to treat the subject exhaustively and from
a practical point of view, so that persons as yet unfamil-
iar with the test may turn to the pages of this book for
help in any difficulties which they may meet in their
work in this line.

36. Sampling. The sample to be tested is first mixed
by pouring the milk from one vessel to another two or

30

Testing Milk and Its Products.

three times so that every portion thereof will
contain a uniform amount of butter fat (29).
The measuring pipette which has a capacity of
17.6 cubic centimeters (see fig. 6), is filled with
the milk immediately after the mixing is com-
pleted, by sucking the milk into it until this
rises a little above the mark around the stem of
the pipette; the forefinger is
then quickly placed over the end
of the pipette before the milk
runs down below the mark. By
slightly releasing the pressure of
the finger on the end of the
pipette, the milk is now allowed
to run down until it j ust reaches
the mark on the stem; the quan-
tity of milk contained in the
pipette will then, if this is cor- ,
rectly made, be exactly 17.6 cc. /
The finger should be dry in
measuringout the milk sothatthe 17 1<
delivery of milk may be readily
checked by gentle pressure on
the upper end of the pipette.

The point of the pipette is now .
placed in the neck of a Babcock \
test bottle (fig. 5), and the milk *
is allowed to flow slowly down
the inside of the neck. Care
must be taken that none of the
milk measured out is lost in this
transfer. The portion of the
life. l^iliP milk remaining in the point of
FIG. 5. Babcock the pipette is blown into the FlG-

mUk test bottle. test bottle. "

The Babcock Test.

31

The best and safest manner of holding the bottle and
the pipette in this transfer is shown in fig. 7. Fig. 8
shows a position which should be avoided, since by hold-
ing the bottle in this way, there is a danger that some of
the milk may com-
pletely fill the neck
of the bottle, and as a
result, flow over the
top of the neck.

Pipettes, the lower
part of which slip
readily into the necks
of the test bottles,
may be emptied by

lowering the pipette }/* into the neck of the bot-
tle till it rests on its rim,
when the milk is allowed
to' run into the test
bottle.

37. Adding acid. The
acid cylinder (fig. 9)
holding 17.5 cc., is filled
to the mark with sulfuric
acid of a specific gravity
of 1.82-1.83. This
amount of acid is care-
fully poured into the
test bottle containing the
milk. In adding the
acid, the test bottle is conveniently held at an angle
(see fig. 7), so that the acid will follow the wall of the
bottle and not run in a small stream into the center of
the milk, the bottle being slowly turned around and the

FIG. 7. The right way of emptying
pipette into test bottle.

32

Testing Milk and Its Products.

neck thus cleared of adhering milk. By pouring the
acid into, the middle of the test bottle, there is also
a danger of completely filling this with acid, in which
case the plug of acid formed will be pushed over the
edge of the neck by the ex-
pansion of the air in the bot-
tle, and may be spilled on the
hands of the operator.

The milk and the acid in
the test bottle should be in
two distinct layers, without
any black portion of partially
mixed liquids between them.
Such a dark layer is often fol-
lowed by an indistinct separa-
tion of the fat in the final
reading. The cause of this
may be that a partial mixture
of acid and milk before the
acid is diluted with the water
of the milk may bring about
too strong an action of the
acid on the milk, and the fat
in this small por-
tion may beslightly
charred by the
strong acid. The
appear an ce of into test bottle.

black flocculent matter in or below the column of fat
which generally results, in either case renders a correct
measurement of fat difficult and at times even impos-

FIG. 8. The wrong way of emptying pipette

The Babcock Test. 33

sible; if the black specks occur in the fat column itself,
the readings are apt to be too high; if below it, the diffi-
culty conies in deciding where the column of fat begins.
38. Mixing milk and acid. After adding the acid, this is
carefully mixed with the milk by giving the test bottle a
rotary motion. In doing this, care should be taken that
none of the liquid spatters into the neck of the test bottle.
When once begun, the mixing should be continued until
completed; a partial and interrupted mixing of the liquids
will often cause more or less black material
to separate with the fat when the test is
finished. Clots of curd which separate at
first by the action of the acid on the milk,
must be entirely dissolved by persistent and
careful shaking of the bottle. Beginners
sometimes fail to mix thoroughly the milk
and the acid in the test bottle. As the acid
is much heavier than the milk, a thin layer
of it is apt to be left unnoticed at the bot-
tom of tlie bottle? unless this is vigorously
acid cylinder, shaken toward the end of the operation.
The mixture becomes hot by the action of the acid on
the water in the milk and turns dark colored, owing to
the effect of the strong sulfur ic acid on the nitrogenous
constituents and the sugar of the milk.

Colostrum milk or milk from fresh cows will form a
violet colored mixture with the acid, due to the action
of the latter on the albumen present in such milk in con-
siderable quantities (23).

When milk samples are preserved by means of potas-
sium bichromate (188), and so much of this material has
3

34

Testing Milk and Its Products.

been added that the milk has a dark yellow or reddish
color, the mixture of milk and acid will turn greenish
black, and a complete solution is rendered extremely
difficult on account of the toughening effect of the bichro-
mate on the precipitated casein. An indistinct separa-
tion of the fat is also sometimes obtained in such samples,
but this difficulty can generally be overcome by using a
little less than the regular quantity of acid.

39. Whirling bottles. After the milk and the acid
have been completely mixed, the test bottle is at once
placed in the centrifugal machine or tester and whirled
for four or five minutes at a speed of 600 to 1200 revo-
lutions per minute, the proper speed being determined
by the diameter of the tester (66). It is not absolutely
necessary to whirl the test bottles in the centrifuge as
soon as the milk and the acid are mixed, although this
method of procedure is much to be preferred ; they may
be left in this condition for any reasonable length of time
(24 hours, if necessary) without the

test being spoiled. If left until the
mixture becomes cold, the bottles
should, however, be placed in warm
water (of about 160° F.) for about 15
minutes before whirling.

Four minutes at full speed is suffi-
cient for the first whirling of the test
bottles in the centrifuge; this will
bring the fat to the surface of the
liquid in the bottle.

40. Adding water. Hot water is now added by means
of a pipette or some special device (Fig. 10), until the
bottles are filled to near the scale on the neck (80). The

FIG. 10. Oil stove for
heating water.

The Babcock Test.

35

bottles are whirled again at full speed for one minute,
and hot water added a second time, until the lower part
of the column of fat comes within the scale on the neck of
the test bottle, preferably to the 1 or 2 per cent, mark, so
as to allow for the sinking of the column of fat, due to the
gradual cooling of the contents of the bottle. By drop-
ping the water directly on the fat in the second filling,
the column of fat will be washed free from light floccu-
lent matter, which might otherwise be entangled therein
and render the reading uncertain or even too high. A
final whirling for one minute com-
pletes the separation of the fat.

41. Measuring the fat. The amount
of fat in the neck of the bottle is
. measured by the scale or gradua-
tions on the neck. Each division
of the scale represents two-tenths of
one per cent, of fat, and the space
filled by the fat shows the per cent,
of butter fat contained in the sam-
ple tested.

The fat is measured from the
lower line of separation between the
fat and the water, to the top of the
fat column, at the point ft, shown in
FIG. 11. Measuring the the figure 11, the reading being thus
cSckTst°bofuien a Bab" taken from a to 6, and not to c or to d.
Comparative gravimetric analyses have shown that the
readings obtained in this manner give correct results.
While the lower line of the fat column is nearly straight,
the upper one is curved, and errors in the reading are.
therefore easily made, unless the preceding rule is observed.

36 Testing Milk and Its Products.

The fat obtained should form a clear yellowish liquid
distinctly separated from the acid solution beneath it.
There should be no black or white sediment in or below
the column of fat, and no bubbles or foam on its surface.
The bottles must be kept warm until the readings are
made, so that the column of fat will have a sharply de-
fined upper and lower meniscus.

The readings should be made when the fat has a tem-
perature of about 140° P., although the results obtained
will not be appreciably affected if the temperature falls
below 120°. The fat separated in the Babcock test solid-
ifies at about 100° P. No reading should be attempted
if the fat is partly solidified, as it is impossible to get an
accurate reading in this case.1

Eeadings of tests of milk made in turbine testers with
tightly closed covers which prevent the free escape of
the exhaust steam (71) will come .2 to .3 per cent, too
high if the temperature of the fat is allowed to rise to
that of the exhaust steam during the process of whirling.
In such cases the test bottles must be allowed to cool to
about 140° (by placing them in water of this tempera-
ture for a few minutes) before readings are taken.2

1 The effect of differences in the temperature of the fat on the readings
obtained will be seen from the following: If 110 and 150° F. be taken as the
extreme temperatures, at which readings are made, this difference of 40°
F. (22.3° C.) would make a difference in the volume of the fat column ob-
tained in case of 10 per cent, milk, of .00064 x 2 x 22.3=. 028514 cc., or .14 per
cent., .00064 being the expansion coefficient of pure butter fat per degree
Centigrade between 50and 100° G.(Zune, Analyse des Beurres,l, 87), and 2, the
volume of the fat in cc. contained in 17.6 cc. of 10 per cent. milk. On 5 per
cent, milk this extreme difference would therefore be about .07 per cent.,
or considerably less than one-tenth of one per cent.

2 See Wis. Experiment Station Rep. XVII, p. 76.

The BabcocTc Test. 37

ICtU-llUg

A

A pair of dividers (Fig. 12) will be found convenient
for measuring the fat, and the liability of error in reading
is decreased by their use. The points of the
dividers are placed at the upper and lower limits
of the fat column (from a to b in Fig. 11). The
dividers are now lowered, one point being placed 'FlQ 12 '
at the zero mark of the scale, and the mark at Dividers,
which the other point touches the scale will show the per
cent, of fat in the sample tested. The dividers must be
tight in the joint to be of use for this purpose.

42. An apparatus called the Calometer, for measuring
the column of fat in bottles with plain, ungraduated necks,
has been placed on the market of late. While the theory
of the apparatus is correct, there are practical objections
to its use, which are likely to prevent its general
adoption.

B — DISCUSSION OF THE DETAILS OF THE
BABCOCK TEST.

43. Although the manipulations of the Babcock test
are few and comparatively simple, various difficulties
may be met with in using it, particularly in the hands of
beginners.

The main points that have to be observed as to appa-
ratus and testing materials in order to obtain correct and
satisfactory results by this test will now be considered,
and such suggestions and help offered, as has been found
desirable from an extensive experience with a great
variety of milk samples, apparatus, and accessories.

38 Testing Milk and Its Products.

1 — GLASSWARE.

44. Test bottles. The test bottles should have a
capacity of about 50 cc., or less than two ounces; they
should be made of well-annealed glass that will stand
sudden changes of temperature without breaking, and
should be sufficiently heavy to withstand the maximum
centrifugal force to which they are likely to be subjected
in making tests. This force may on the average not be
far from 30.65 Ibs. (see 66), which is the pressure exerted
in whirling the bottles filled with milk and acid in a
centrifugal machine of 18 inches diameter at a speed of
800 revolutions per minute.

Special forms of test bottles used in testing cream and
skim milk are described under the heads of cream and
skim milk testing (89, 90, 91, 99).

When 17.6 cc., or 18 grams of milk (48), are measured
into the Babcock test bottle, the scale on the neck of the
bottles shows directly the per cent, of fat found in the
milk. The scale is graduated from 0 to 10 per cent.
10 per cent, of 18 grams is 1.8 grams. As the specific
gravity of pure butter fat (i. e. its weight compared
with that of an equal quantity of pure water) at the
temperature at which the readings are made (about 140°
F.), is 0.9, then 1.8 grams of fat will occupy a volume
of -l<§ =2 cubic centimeters. The space between the 0 and
10 per cent, marks on the necks of the test bottles must
therefore hold 2 cc., if correctly made. The scale is
divided into 10 equal parts, each part representing one
per cent., and each of these is again sub- divided into
five equal parts. Each one of the latter divisions there-

The Babcock Test. 39

fore represents two-tenths of one per cent, of fat when
17.6 cc. of inilk is measured out. The small divisions
are sufficiently far apart in most Babcock test bottles to
make possible the estimation of one-tenth of one per
cent, of fat in the samples tested.

As the necks of Babcock test bottles vary in diameter,
each separate bottle must be calibrated by the manufac-
turers; the length of the scale is not, for the reason given,
apt to be the same in different bottles. 1

If the figures and lines of the measuring scale become
indistinct by use, the black color may be restored by
rubbing a soft lead pencil over the scale, or by the use of
a piece of burnt cork after the scale has been rubbed
with a little tallow. On wiping the neck with a cloth or
a piece of paper the black color will show in the etchings
of the glass, making these plainly visible.

45. Marking test bottles. Test bottles can now be
bought with a small band or portion of their neck or
body ground, or "frosted," for numbering the bottles
with a lead pencil. Bottles without this ground label
can be roughened at any convenient spot by using a wet
fine file to roughen the smooth surface of the glass. There
is this objection to the latter method that unless carefully
done, it is apt to weaken the bottles so that they will
easily break, and to both methods, that the lead pencil
marks made on such ground labels may be effaced dur-
ing the test if the bottles are not carefully handled.

i A flat-bore test bottle and one with a brass collar and screw used for
opening and closing a small hole in the neck of the test bottle have lately
been placed on the market by the Wagner Glass Works of New York.
These have been tried by us, but no particular advantage over the round
necks was discovered.

40 Testing Milk and Its Products.

Small strips of tin or copper with a number stamped
thereon are sometimes attached as a collar around the
necks of the bottles. They are, however, easily lost,
especially when the top of the bottle is slightly broken,
or at any rate, are soon corroded so that the numbers
can only be seen with difficulty.

The best and most permanent label for test bottles is
made by scratching a number with a marking diamond
into the glass directly above the scale on the neck of the
bottles. In ordering an outfit, or test bottles alone, the
operator may specify that the bottles are to be marked 1
to 24, or as many as are bought, and the dealer will then
put the numbers on with a marking diamond.

A careful record should be kept of the number of the
bottle into which each particular sample of milk is meas-
ured. Mistakes are often made when the operator trusts
to his memory for locating the different bottles tested at
the same time.

46. Cleaning test bottles. The fat in the neck of the
test bottles must be liquid when these are cleaned. In
emptying the acid the bottle should be shaken in order
to remove the white residue of sulfate of lime, etc., from
the bottom; if the acid is allowed to drain out of the
bottle without shaking it, this residue will be found to
stick very tenaciously to the bottom of the bottle in the
subsequent cleaning with water.

A convenient method of emptying test bottles is shown
in the illustration (Fig. 13). After reading the fat col-
umn, the bottles are placed neck down, in the half- inch
holes of the board cover of a five-gallon stoneware jar.

The Bdbcock Test.

41

An occasional shaking while the liquid is running from
the bottles will rinse off the precipitate of sulfate of

lime. A thor-
ough rinsing
with boiling hot
water by means
of an apparatus,
devised by one of
us1 (see Fig. 14),
is generally suf-
ficient to remove
E all grease and
dirt, as well as

FIG. 13. Waste-Acid Jar. acid Solution,

from the inside of the bottles. When the bottles have
been rinsed, they are placed in an inverted position to
drain, on a galvanized iron rack, as shown in Fig. 15,
where they are kept until needed. The outside of the
bottles should occasionally be wiped clean and dry.

47. The amount of unseen fat that clings to test bottles
used for testing milk or cream, is generally not sufficient
to be noticed in the results obtained in testing whole
milk, but it plays an important part in testing samples
of separator skim milk. It may be readily brought to
light by making a blank test with clean water in bottles
used for testing ordinary milk, which have been cleaned
by simply draining the contents and rinsing once or
twice with hot water; at the conclusion of the test the
operator will generally find that a few drops of fat —

i Farrington.

42

Testing Milk and Its Products.

sometimes enough to condemn a separator — will collect
in the neck of the bottles.

FIG. 14. Apparatus for cleaning test bottles. A, apparatus in position;
the water flows from the reservoir through the iron pipe b into the in-
verted test bottle d through the brass tube c, screwed into the iron pipe.
.B shows construction of the rubber support on which the top of the test
bottle rests;/, draining sink.

Boiling hot water will generally clean the grease from
glassware for a time, but all test bottles should, in addi-
tion, be given an occasional bath in some weak alkali or
other grease- dissolving solution. Persons doing consid-
erable milk testing will find it of advantage to provide

The BabcocJc Test.

43

themselves with a small copper tank, which can be filled
with a weak alkali-solution (Figs. 16 and 17). After
having been rinsed
with hot water, the
test bottles are placed
in the hot solution
in the tank, where
they may be left

, FIG. 15. Draining-rack for test bottles.

completely covered

with the liquid. If the tank is provided with a small
faucet at the bottom, the liquid can be drawn off when

the test bottles are
wanted.

A tablespoonful
ofSavogran to about
two gallons of wa-
ter will make a very
satisfactory clean-
ing solution ; sal
soda, Gold Dust,
Lewis' lye or Bab-
bitt's potash are
equally efficient.
The cleansing pro-
perties of solutions
of any of these sub-
stances are i n-
creased by warrn-

FIG. 16. Tank for cleaning test bottles. ing the 1 iquid. The

test bottles must be rinsed twice with hot water after
they are taken from this bath.

44

Testing Milk and Its Products.

The black stains that sometimes stick to the inside of
test bottles after prolonged use, can be removed with a
little muriatic acid.

PIG. 17. Back for holding test bottles in tank shown In Fig. 16.

48. Pipette. The difference in the weights of various
samples of normal milk generally falls within compara-
tively narrow limits; if a given volume of water weighs
one pound, the same volume of the usual grades of nor-
mal milk will weigh from 1.029 to 1.033 pounds, or on
the average 1.03 Ibs. 18 grams of water measures 18
cc.1; 18 grams of milk will therefore take up a smaller
volume than 18 cc., viz: 18 divided by 1.03, which is
very nearly 17.5. This is the quantity of milk taken
in the Babcock test. A certain amount of milk will ad-
here to the walls of the pipette when it is emptied, and

i Cubic centimeters (abbreviated: cc.) are the standard used for meas-
uring volume in the metric system, similar to the quart or pint measure
in our ordinary system of measures. One quart is equal to a little less than
1,000 cubic centimeters. In the same way, grams represent weight, like
pounds and ounces. One cc. of water at 4° Centigrade weighs 1 gram; 1,000
grams (=1 kilogram) are equal to 2.2 Ibs. Avoirdupois. (See Appendix for
Comparisons of Metric and Customary Weights and Measures.)

The Bdbcock Test.

45

FIG. 18. Pip-
ette points—

A, proper con-
struction; B,
undesirable
construction

this thin film has been found to weigh about one-tenth
of a gram; consequently 17.6 cc. has been adopted as the
capacity of the pipette used for delivering
18 grams of milk.

For convenience in measuring the milk,
the shape of the pipette is of importance.
The mark on the stem should be two inches
or more from the upper end of the pipette.
The lower part should be small enough to
fit loosely into the neck of the test bottle,
and not contracted to a fine hole at the
point; the point should be large enough to
allow a quick emptying of the pipette
(Fig. 18).

49. Fool Pipettes. Soon after the Babcock test began to be
generally used at creameries as a method of paying for the milk,
a creamery supply house put on the market a 20 cc. milk-meas-
uring pipette, which was claimed to show the exact butter
value of milk, instead of its content of butter fat, as is the case
in using the ordinary 17.6 cc. pipette. A 20 cc. pipette will
deliver 2.4 cc. more milk than a 17.6 cc. pipette, (or 13.6 per
cent.), and the results obtained by using these pipettes will,
therefore, be about 13.6 per cent, too high. In considering the
subject of Overrun (214) it is noted that the excess of butter
yield over the amount of fat contained in a certain quantity of
milk will range from about 10 to 16 per cent., or on the average
about 12 per cent. 20 cc. pipettes may, therefore, give approx-
imately the yield of butter obtained from a quantity of milk,
but as will be seen, this yield is variable, according to the skill
of the butter maker and according to conditions beyond his
control; it cannot therefore be used as a standard in the same
manner as the fat content of the milk. Similar 22 cc. pipettes
were also sent out. These pipettes created a great deal of con-
fusion during the short time they were on the market, and

46 Testing Milk and Its Products.

were popularly termed "fool pipettes." It is not known that
any of these pipettes have been sold of late years.

50. Acid measures. A 17.5 cc. glass cylinder (Fig. 9)
for measuring the acid is generally included in the outfit,
when a Babcock tester is bought. This cylinder answers
every purpose if only occasional tests are made; the acid
is poured into the cylinder from the acid bottle as
needed, or a quantity of acid sufficient for the number of
test bottles to be whirled at a time, is poured into a small
glass beaker provided with a lip, or into a small porce-
lain pitcher; these may be more easily handled than the
heavy acid bottle, and the acid measure is then filled
from such a vessel.

Where a considerable number of tests are made regu-
larly, the acid can be measured into the test bottles
faster and with less danger of spilling, by using some one
of the many devices proposed for this purpose. There
is some objection to nearly all of these appliances, auto-
matic pipettes, burettes, etc., although they will often
give good satisfaction for a time while new. Sulfuric
acid is very corrosive, and operators as a rule take but
poor care of such apparatus, so that it is a very difficult
matter to design a form which will remain in a good work-
ing order for any length of time. Automatic pipettes
attached to acid bottles or reservoirs, to prove satisfac-
tory, must be made entirely of glass, and strong, of sim-
ple construction, tightly closed and quickly operated.

51. The Swedish acid bottle answers these requirements
better than any other device known to the writers at the
present time. Its use is easily understood (see Fig. 19);
it gives good satisfaction if the hole in the glass stop

The Babcock Test.

47

cock through which the acid passes has a diameter of at
least one- eighth of an inch, as is generally the case. We
have used or inspected some half a
dozen other devices, which have
been placed on the market by vari-
ous dealers for delivering the acid,
but cannot recommend them for
use in factories or outside of chem-
ical laboratories.

52. Instead of measuring out the
acid, Bartlett 1 suggested adding it
directly to the milk in the test bot-
tles, till the mixture rises to a mark
on the body of the bottle at the
FIG. 19. Swedish acid bot- point where this will hold 37.5 cc..

tie; the side-tube is made f

to hold 17.5 cc. of acid. j. 6t? the total volume of milk and
acid (89). This method of adding the acid is in the line
of simplicity, but has not become generally adopted. If
the method is used the marks should be put on by the
manufacturers, as the operator in attempting to do so
will be apt to weaken or break the bottles.

CALIBRATION or GLASSWARE.

Test bottles. The Babcock milk test bottles are so
constructed that the scale or graduation of the neck
measures a volume of 2 cubic centimeters, between the
zero and the 10 per cent marks (44). The correctness
of the graduation may be easily ascertained by one of the
following methods:

53. (A.) Calibration with mercury. 27.18 grams of
metallic mercury are weighed into the perfectly clean

i Maine experiment station, Bull. No. 31.

48 Testing Milk and Its Products.

and dry test bottle. Since the specific gravity of mer-
cury is 13.59, double this quantity will occupy a volume
of exactly 2 cubic centimeters (48). The neck of the
test bottle is then closed with a small, smooth and soft
cork, or a wad. of absorbent cotton, cut off square at one
end, the stopper being pressed down to the first line of
the graduation. The bottle is now inverted so that the
mercury will run into its neck. If the total space in-
cluded between the 0 and 10 marks is just filled with the
two cubic centimeters of mercury, the graduation is cor-
rect. Bottles, the whole length of the scale of which
vary more than two-tenths of one per cent., are inaccu-
rate and should not be used.

The mercury may be conveniently transferred from one
test bottle to another, by means of a thin rubber tube
which is slipped over the end of the necks of both bot-
tles, and one weighing of mercury will thus suffice for a
number of calibrations. In transferring the mercury,
care must be taken that none of it is lost, and that small
drops of mercury are not left sticking to the walls of the
bottle emptied. A sharp tap on the bottle with a lead
pencil will help to remove minute drops of mercury from
the inside of it. Unless the bottles to be calibrated are
perfectly clean and dry, it is impossible to transfer all
the mercury from one bottle to another.

After several calibrations have been made, the mer-
cury should be weighed again in order to make certain
that none has been lost by the various manipulations.
The scales, figs. 33 and 34, shown in (94), are sufficiently
delicate for making these weighings.

54. Cleaning mercury. Even with the best of care,
mercury used for calibration of glassware will gradually

The Babcock Test. 49

become dirty, so that it will not flow freely over a clean
surface of glass. It may be cleaned from mechanical
impurities, dust, films of grease, water, etc., by filtration
through heavy filter paper. This is folded the usual
way, placed in an ordinary glass funnel and its point
perforated with a couple of pin holes. The mercury will
pass through in fine streams, leaving the impurities on
the filter paper. Mercury may be freed from foreign
metals, zinc, lead, etc., sometimes noticed as a grayish,
thin film on its surface, by leaving it in contact with
common nitric acid for a number of hours; the mercury
is best placed in a shallow porcelain or granite ware dish
and the nitric acid poured over it, the dish being covered
to keep out dust. The acid solution is then carefully
poured off and the mercury washed with water; the lat-
ter is in turn poured off, and the last traces of water
absorbed by means of clean, heavy filter paper.

The mercury to be used for calibration of glassware
should be kept in a strong bottle, closed by an ordinary
stopper. In handling mercury, care must be taken not
to spill any portion of it; finger-rings should be removed
when calibrations with mercury are to be made.

Mercury forms the most satisfactory and accurate ma-
terial for calibration of test bottles, on account of its
heavy weight and the ease with which it may be manip-
ulated. Equally correct results may, however, with
proper care be obtained by using water for the calibration.

(B.) Calibration with water. This may be done by
means of a delicate pipette or burette, or by weighing in
a somewhat similar manner, as explained in case of cali-
bration with mercury.
4

50 Testing Milk and Its Products.

55. a, Measuring the water. Fill the test bottle with
water to the zero mark of the scale; remove any surplus
water and dry the inside of the neck with a piece of filter
paper or clean blotting paper; then measure into the
bottle 2 cc. of water from an accurate pipette or burette,
divided to ^0 of a cubic centimeter. If the graduation
is correct, 2 cc. will fill the neck exactly to the 10 per
cent, mark of the scale.

56. b, Weighing the water. Fill the bottle with water
to the zero mark of the scale and remove any surplus
water in the neck, as before. Weigh the bottle with the
water contained therein. Now fill the neck with water
to the 10 per cent, mark, and weigh again. The differ-
ence between these weights should be 2 grams.

In all cases when calibrations are to be made, the test
bottles, or other glassware to be calibrated, must be thor-
oughly cleaned with strong sulfuric acid, or soda lye, and
washed repeatedly with pure water, and dried. Glass-
ware is not clean unless water will run freely over its
surface, without leaving any adhering drops.

57. (C.) The Trowbridge method of calibration.1 An
extremely simple and accurate method of calibrating test
bottles has been proposed by Mr. O. A. Trowbridge of
Columbus, Wis. He conceived the idea of measuring
the capacity of the graduated portion of the neck of a
milk test bottle with a piece of metal which is carefully
filed to such a size that it will displace exactly two cubic
centimeters of water. He used a thirty-penny wire nail,
cutting off the head of the nail and attaching to it a short
piece of fine wire, either looped at one end, as shown in

i Hoard's Dairyman, Mar. 8, 1901, by De Witt Goodrich.

The Babcock Test.

51

Fig. 20 (A), or as one straight piece of about three inches

long.

The wire serves as a handle for lowering the measure

into the neck of the test bottles. If the wire is attached

as shown in Fig. 20 (A),
a string can be fastened
to the loop for holding
the measure in the
proper place in the test
bottle.

When a test bottle is
to be calibrated by this
standard measure, it is
filled with water to the
zero mark on the neck
of the bottle. The water
adhering to the neck is
carefully removed with a
strip of blotting paper,
and the measure (A), is
then lowered into the
test bottle, as shown in
(B), to the point where

\

B

the wire loop is attached.
If the water rises from 0
to 10 on the neck when
the point of the measure
is also at ten, the scale is

FIG. 20. (A) Trowbridge calibrator as correct. If greater vari-
used in test bottle (B). (C) Nafls modi-
fication of (A). ations than .2 of one per

cent, occur, the bottle should be rejected.

The diagram (C), shows how one of these testers may
be made in two sections, and the accuracy of the 5 as well

52 Testing Milk and Its Products.

as the 0 and 10 marks on the scale ascertained. This
modification was proposed by Louis F. Nafis & Co. , Chi-
cago.

The lower section of this tester will displace 1 cc. of
liquid and raise it from 0 to the 5 mark, but the tester
must be lowered slowly so that the upper section will not
come in contact with the liquid until the 5 mark is tested.
After ascertaining the correctness of this point, both sec-
tions are lowered so that the water rises above the top of
the upper section and the accuracy of the 10 mark is
also tested.

58. The standard measure. In the place of an iron
nail, a piece of copper or glass rod may be advantage-
ously used as a standard measure. The standardization
is most conveniently done by weighing; since the specific
gravities of iron, copper and glass are 7.8, 8.9 and about
2. 7, respectively. Pieces of these materials replacing 2 cc.
of a liquid, will weigh 15.6, 17.8 and 5.4 grams, for iron,
copper and glass in the order given.

A measure of the right weight may be suspended by a
very fine copper or platinum wire (melted into the glass
rod if this material be chosen), and is used directly for
calibrating test bottles as described above. Before a
measure so made is used as a standard, its accuracy should
be determined by weighing the amount of water at a temp,
of 17.5° C, which it replaces. The specific gravity of glass
especially, varies somewhat according to its composition,
so that a standardization of a measure by weight alone
cannot be depended upon always to give correct results.

59. In submerging the measure in the test bottle to be
calibrated, care must be taken that all air bubbles are

The Bdbcock Test. 53

removed before the position of the meniscus of the water
is noted; if a metal standard measure is used, it must be
kept free from rust or tarnish.

60. Intermediate divisions. The space between 0 and
10 on the scale of the Babcock test bottle is divided into
50 divisions, each five of which, as previously shown,
representing 1 per cent. (44). Since these intermediate
divisions are generally made with a dividing machine,
they are as a rule correct, but it may happen that the
divisions have been inaccurately placed, although the
space between 0 and 10 is correct. The accuracy of the
intermediate divisions can be ascertained by sliding
along the scale a strip of paper upon which has been
marked the space occupied by one per cent., and com-
paring the space with those of each per cent, on the scale.

61. Calibration of skim milk test bottles. The value of
each division on the skim milk bottles is one-twentieth
of one per cent. (99) and there are ten of these divisions
or .1 cc. in the whole scale which shows .5 per cent,
fat. It requires very careful work to calibrate this scale
and it is best done by weighing the amount of mercury
which will just fill the space between the first and the last
divisions (53) ; the correct weight of this mercury is 1.359
grams.

62. Calibrating cream test bottles. The cream bottles
may be calibrated by any of the methods given for milk
bottles. A cream test bottle neck that measures thirty
per cent, fat will hold 6 cc., and 6 grams of water or
81.54 grams of mercury.

The Trowbridge method of calibrating milk test bot-
tles may also be found convenient for cream bottles and

54 Testing Milk and Its Products.

the same standard measure used. The part of the scale
from 0 to 10 being calibrated first, then from 10 to 20
and 20 to 30 per cent, in the same way.

63. Pipette and acid cylinder. The pipette and
the acid cylinder used in the Babcock test may be cali-
brated by any of the methods already given. Sufficiently
accurate results are obtained by weighing the quantity
of water which each of these pieces of apparatus will
hold, viz., 17.6 grams and 17.5 grams, respectively. The
necessity of previous thorough cleaning of the glassware
is evident from what has been said in the preceding.
The pipette and the acid measure may be weighed empty
and then again when filled to the mark with pure water,
or the measureful of water may be emptied into a small
weighed vessel, and this weighed a second time. In
either case the weight of the water contained in the
pipette or acid measure is obtained by difference.1

Calibrations of the acid cylinder are generally not called
for, except as a laboratory exercise, since small variations
in the amount of acid measured out do not affect the
accuracy of the test.

2. — CENTRIFUGAL MACHINES.

64. The capacity of the testing machine to be selected
should be governed by the number of tests which are
likely to be made at one time. For factory purposes a
twenty-four to thirty bottle tester is large enough, and
to be preferred for a larger tester, even if toward a hun-

1 1 cubic centimeter of distilled water weighs I gram, when weighed in
a vacuum at the temperature of the maximum density of water (4° C); for
the purposes of calibration of glassware used in the Babcock test, suf-
ficiently accurate results are, however, obtained by weighing the water in
the air and at a low room-temperature (60° F.).

The Babcock Test. 55

dred samples of milk are to be tested at a time. The
operator can use his time more economically in running
a machine of this size than one holding fifty or sixty bot-
tles; the work of filling or cleaning the bottles and
measuring the fat can be done while the tester is running
if a double supply of bottles is at hand. Large testers
require more power than smaller ones, and when sixty
tests are made at a time, the fat column in many bottles
will get cold, before the operator has time to read them,
unless special precautions are taken for keeping the
bottles warm.

65. The tester should be securely fastened to a solid
foundation and set so that the revolving wheel is level.
The latter must be carefully balanced in order that the
tester may run smoothly at full speed when empty. A
machine that trembles and shakes when in motion is
neither satisfactory nor safe, and the results obtained are
apt to be too low. High-standing machines are more
apt to cause trouble in this respect than low machines,
and should therefore be subjected to a severe test before
they are accepted.

If all the sockets are not filled with bottles when a test
is to be made, the bottles must be placed diametrically
opposite one another so that the machine will be balanced
when run. The bearings should be kept cleaned and
oiled with as much care as the bearings of a cream sepa-
rator.

The cover of the machine should always be kept closed
while the bottles are whirled, and should not be removed
until the machine stops; the cover should be tight fitting
and may be fastened with hooks soldered on the side of

56 Testing Milk and Its Products.

the machine; test bottles sometimes break while the
machine is running at full speed, and every possible pre-
caution should be taken to protect the operator from any
danger from spilled acid or broken glass.

66. Speed required for the complete separation of the
fat. There is a definite relation between the diameter of
the Babcock testers and the speed required for a perfect
separation of the fat. In the preliminary work with the
Babcock test the inventor found that with the machine
used, the wheel of which had a diameter of eighteen
inches, it was necessary to turn the crank, so as to give
the test bottles seven or eight hundred revolutions per
minute, in order to affect a maximum separation of fat;
later work has shown that this speed is ample. Taking
therefore this as a standard, the centrifugal force to which
the contents of the test bottles are subjected when sup-
ported on an eighteen inch wheel and turned 800 revolu-
tions per minute, can be calculated as follows:

The centrifugal force, F, acting on the bottles is expressed by
the formula

w. v2

F=~3£2F • • • • • • (I)

in which w = the weight of the bottle with contents, in pounds;
v = the velocity, in feet per second, and r = the radius of the
wheel, in feet.

When the wheel is turned 800 times a minute, a bottle sup-
ported on its rim will travel 2?r rx 86°00 =2X3.1415 X & X 8e000=62.83
feet per second. The weight of a bottle, with milk and acid, is
very near 3 ounces, or j3e of a pound. Substitutiug these values
for v and w, gives

=30.65 lb,

The bottles are therefore, under the conditions given, sub-
jected to a pressure of about 30.65 pounds. IB order to calculate

The Babcock Test. 57

the speed required for obtaining this force in case of machines
of other diameters, the value of v in formula (I) is found from

Substituting the values for F and w,

r_ /32.2 X 30.65 r

V 3

= V/5264 r

In this equation the values r = 5, 6, 7, 8, 9, 10, 11, 12 inches
are substituted in each case (^ r\, j7^, . . . }| feet), and the
velocity in feet per second then found at which the bottles are
whirled when placed in wheels of diameters 10 to 24 inches, and
subjected in each case to a centrifugal force of 30.65 Ibs. As the

number of revolutions per minute = — , v being as before

2 TT r

the velocity in feet per second, and r the radius of the wheel,
the speed at which the wheel must be turned, is found by sub-
stituting for v the values obtained in the preceding calculations
in case of wheels of different diameters. The results of these
calculations are given in the following table:

Diameter Velocity in feet Number of revolutions

of wheel, d. per second, v. of wheel, per minute.

10 46.84 1074

12 51.31 980

14 55.43 909

16 59.26 848

18 62.84 800

20 66.24 759

22 69.47 724

24 72.56 693

These figures show that a tester, for instance, 25 inches in
diameter, requires less than 700 revolutions per minute for a
perfect separation of the fat in Babcock bottles, while a ten-
inch tester must have a speed of nearly 1100 revolutions, in
order to obtain the same result.

The speed at which testers of different diameters should be
run to affect a complete separation has been calculated by Prof.
C. L. Beach in the following manner1. The same standard as

i Private communication.

58 Testing Milk and Its Products.

before is taken, viz., 800 revolutions for an 18 inch tester (radius
9 inches); then if x designate the radius of the tester and y the
speed required, we have

xy2=9x8002, or
-, » X 800*

The figures obtained by the use of this formula are similar to
those given in the preceding table.

67. To find the number of turns of the handle corres-
ponding to the number of revolutions made by the wheel,
the handle is given one full turn, and the number of
times which a certain point or part of the wheel revolves,
is noted. If the wheel has a diameter of 20 inches, and
revolves 12 times for one turn of the handle, the latter
should be turned \*£ =63 (see table), or about once every
second, in order to affect a maximum separation of fat.
By counting the number of revolutions, watch in hand,
and consulting the preceding table, the operator will
soon note the speed which must be maintained in case of
his particular machine. It is vitally important that the
required speed be always kept up; if through careless-
ness, worn-out or dry bearings, slipping belts, etc., the
speed is slackened, the results obtained will be too low;
it may be a few tenths, or even more than one per cent.
Care as to this point is so much the more essential, as the
results obtained by too slow whirling may seem to be all
right, a clear separation of fat being often obtained even
when the fat is not completely separated.

68. Ascertaining the neccessary speed of testers. In
buying a tester the operator should first of all satisfy
himself at what speed the machine must be run to give
correct results: the preceding table will serve as a guide

The Babcock Test. 59

on this point. He should measure out a dozen tests of
the same sample of milk, and whirl half the number at
the speed required for machines of the diameter of his
tester. Whirl the other half at a somewhat higher
speed. If the averages of the two sets of determinations
are the same, within the probable error of the test (say,
less than one-tenth of one per cent.) the first whirling
was sufficient, as it is believed will generally be the case.
If the second set of determinations come higher than the
first set, the first whirling was too slow, and a new series
of tests of the same sample of milk should be made to
ascertain that the second whirling was ample.

This method will test not only the speed required with
the particular machine at hand, but will also serve to
indicate the correctness of the calibration of the bottles.
A large number of tests of the same sample of milk
made as directed (pouring the milk once or twice previ-
ous to taking out a pipetteful for each test) should not
vary more than two-tenths of one per cent, at the outside,
and in the hands of a skilled operator will generally
come within one -tenth of one per cent. If greater dis-
crepancies occur, the test bottles giving too high or too
low results should be further examined, and calibrated
according to the directions already given (53 et seq.}.

69. Hand testers. When only a few tests are made at
a time, and at irregular intervals, as in case of dairymen
who test single cows in their herds, a small hand tester
answers every purpose. These may be had in sizes from
two to twelve bottles. In selecting a particular make of
tester the dairyman has the choice of a large number of
different kinds of machines. It is a source of regret that

60

Testing Milk and Its Products.

most of the machines placed on the market for this pur-
pose in the past have been so cheaply and poorly con-
structed as to prove
very unsatisfactory
after having been
in use for a time.
The sharp compe-
tition between man-
ufacturers of dairy
supplies and the
clamor of dairymen
for something
cheap, fully ac-
count for this con-

FiG.21. "No-tin "test. dition of affairs.

This applies especially to the many machines made with
belts or friction application of power. The main objec-
tion to these ma-
chines is the un-
certainty of the
speed obtained,
when they have
been in use for
some time, and
the belt or fric-
tion appliance
begins to slip.
Hand testers
made with cog
gear wheels are
more to be de-
pended on for

giving the nee- FIG. 22. Type of Babcock hand testers.

essary speed than belt or friction machines ; the earlier

The Babcock Test.

61

machines of this kind were very noisy, but at the present
time the best machines on the market are of this type.

These are pro-
vided with spiral
cog gear and ball
bearings, are
strongly made
and will run
smoothly and
without noise
(Figs.21-22);in
cog gear ma-
chines the bot-
tles are always
whirled at the
speed which the
number of turns
made by the
crank would in-
dicate.

70. Power testers. For factory purposes, steam tur-
bine machines (Figs. 23-24) are most satisfactory when
well made and
well cared for.
They should al-
ways be pro-
vided with a
speed indicator
and steam
gauge, both for
the purpose of
knowing that
sufficient speed

is attained, and FIG. 24. Type of Babcock steam turbine testers.

FIG. 23. Type of Babcock steam turbine testers.

62 Testing Milk and Its Products.

also to prevent what may be serious accidents from
a general smash up, if the turbine "runs wild" by
turning on too much steam. The revolving wheel of the
tester should be made of wrought or malleable iron, or of
wire, so that it will not be broken by the centrifugal
force, thus avoiding serious accidents. The swinging
pockets which hold the test bottles in some machines,
should be so made that the bottles will not strike the
center of the revolving frame when in a horizontal posi-
tion. Tests have often been lost by the end of the neck
catching at the center, the bottles thus failing to take an
upright position when the whirling stops.

71. The exhaust steam pipe of turbine testers should
not have too many turns in it or be much reduced in size
from that of the opening in the tester. A free escape of
the exhaust steam is necessary to prevent the steam col-
lecting in the test bottle chamber and overheating the
test bottle when whirled (41).

The cover of the tester should have an opening in it
which is provided with a sliding damper or some arrange-
ment by which this opening can be closed when desired.
If whole milk or cream is being tested, this hole in the
cover should be open so that a draft of air may enter the
test bottle chamber during whirling, and force the steam
out of the bottle chamber into the exhaust pipe. If skim
milk is being tested, all openings in the cover should be
closed. This shuts off the draft of air, and the exhaust
steam heats the test bottles during whirling to 200° F. in
some cases. This high temperature aids in separating
the last traces of fat in skim milk and gives a most accu-
rate test of samples containing less than one-tenth per

The Babcock Test. 63

cent. fat. Some of the most recent makes of turbine test-
ers are provided with holes in the cover and dampers.
A thermometer is also placed in the cover.

3 — SULPHURIC ACID.

72. The sulfuric acid to be used in the Babcock test
should have a specific gravity of 1.82 -1.83. 1 The com-
mercial oil of vitriol which can be bought for about
2 cents a pound in carboy lots, is commonly used. One
pound of acid is sufficient for fifteen tests. The acid
should be kept in stoppered glass bottles, preferably
glass or rubber stoppered ones, since a cork stopper is
soon dissolved by the acid and rendered useless. If the
bottle is left uncorked the acid will absorb moisture from
the air and will after a time become too weak for use in
this test. Lead is the only common metal which is not
dissolved by strong sulfuric acid; where considerable
milk testing is done, it is therefore desirable to provide
a table covered with sheet lead on which the acid may
be handled.

The acid dissolves iron, tin, wood and cloth, and burns
the skin. If acid is accidently spilled, plenty of water
should be used at once to wash it off. Ashes, potash,
soda, and ammonia neutralize the action of the acid, and
a weak solution of any one of these alkalies can be used
after the acid has been washed off with water. The red
color caused by the action of the acid on clothing can be
removed by wetting the spot with weak ammonia water;

i A specific gravity of 1.82 means that a given volume of the acid weighs
1.82 times as much as the same volume of water at the same temperature
(see also under Lactometer, 106).

64 Testing Milk and Its Products.

the ammonia must, however, be applied while the stain
is fresh, and is in its turn washed off with water.

73. Testing the strength of the acid. The strength of
the acid can be easily tested by the use of such a balance
as shown in Fig. 33 (94). A dry test bottle is weighed,
and then filled with acid exactly to the zero mark, or to
any other particular line of the scale. It is then again
weighed accurately; the difference between these two
weights will give the weight of the acid in the bottle.
Next empty the bottle and rinse it thoroughly with water
(until the water has no longer an acid taste); fill the
bottle with water to the same line as before and weigh ;
the difference between this weight and that of the empty
bottle gives the weight of the same volume of water as
that of the acid weighed. Divide the weight of the acid
by the weight of the water; the quotient gives the spe-
cific gravity of the acid. If this is between 1.82 and
1.83, the strength of the acid is correct. The outside of
the test bottle should always be wiped dry before the
liquids are weighed in it. Unless great care is taken in
measuring out the acid and the water, and in weighing
both these and the test bottle, the results obtained will
not be trustworthy.

74. Too strong acid can sometimes be successfully used
by taking less than the required amount of each test, e. g.
about 15 cc. Operators are warned against reducing the
strength of the acid by adding water to it, as accidents
are very apt to occur when this is done. A too strong
acid can, if desired, be weakened by simply leaving the
bottle which holds it, uncorked for a time, or by pouring
the acid into a bottle containing a small quantity of

The Babcock Test. 65

water. In the latter case the first portions of acid should
be added carefully, a little at a time, shaking the bottle
after each addition, so as not to cause it to break from
the great heat evolved in mixing the acid and the water.
Never dilute sulfuric acid by pouring water into it.

75. If the acid is too weak, correct results may some-
times be obtained by using more than the specified
quantity, say 20 cc. If a good test is not obtained with
this quantity of acid, a new lot must be secured, as its
specific gravity in such a case is below 1.82. The ob-
serving operator will soon be able to judge of the
strength of the acid by its action on milk in mixing the
two liquids in the Babcock test bottles; it is indeed re-
markable what slight differences in the specific gravity
of the acid will make themselves apparent in working
the test, as regards the rapidity with which both the
curdled milk is dissolved and the mixture of acid and
milk turns black.

76. Strength of sulfuric acid. The relation between
the strength of sulfuric acid and its specific gravity will
be seen from the following table:

Strength of Sulfuric Acid (Lunge and Isler, 1890. )

Sulfuric Acid Specific Gravity

(H2SO±). ( 15° C, water A° C).

97 per cent 841

96 " 840

95 " 839

94 " .837

93 " 834

92 " 830

91 " 1.825

90 " 1.820

89 " 1.815

88 " 1.808

5

- CORRECT

66 Testing Milk and Its Products.

It will be noticed that the sulfuric acid to be used in
the Babcock test should contain 90 to 92 per cent, of acid
(H2SO4); slightly weaker or stronger acid than this
may, as previously stated, be used by adjust-
ing the quantity of acid taken for each test to
the strength of the acid, but successful tests
cannot be made with acid weaker than 89 per
cent, or stronger than 95 per cent.
(TOO STRONG 77. The Swedish acid tester (Fig. 24) is a
small hydrometer, intended to show whether
the acid to be used in the Babcock test is of
the correct strength. We have examined a
number of these testers, and have found them
practically useless for the purpose intended.
The reason for this is that the instrument is
not sufficiently sensitive; while the testers ex-
amined were found to sink to the line marked
Correct on the scale, when lowered into sulfuric
acid of a specific gravity of 1.83, they would
sink to a point much nearer the same mark,
Swedish add than to the lines marked Too strong or Too
weak, respectively, when lowered into either
too strong or too weak acid.

An examination of the proportionate parts of these testers
shows that such must be the case: The total weight of the
testers varies between 7 and 8 grams; the diameter of the stem
is nearly 5 millimeters, and the distance between the two lines
marked Too strong and Too weak is 13.5 millimeters. A good
hydrometer, such as used in chemical laboratories for determin-
ing the specific gravity of liquids of 1.8 to 2.0, weighs about 75
grams; the diameter of the stem is 6 mm., and the distance
between the 1.82 and 1.84 marks on the scale is 15.5 mm.; these
limits may be taken to represent too weak and too strong acid,

The BabcocJc Test. 67

respectively. Comparing such a hydrometer with the Swedish
tester, the weight of the former would make it ten times as
sensitive as the latter, if the size of the stem was the same in
either case; as it is, the tester has the advantage in point of
thinness of stem (see 106), as the volumes of the same lengths of
stem in the two instruments are as the squares of their diam-
eter, i. e., as 25:36. This means that the Swedish testers are

36 1

only 1Q x ^ = 7 as sensitive as the hydrometer, or a difference

on the scale of the latter amounting to 15.5 mm. (see above),
would represent only 2.2 mm., on the scale of the Swedish
tester. The line marked Too strong must therefore be only 1.1
mm. (2*3 of an inch) below the Correct line; and that marked
Too weak the same distance above the line. But this is too
small a distance to be differentiated by persons unfamiliar
with the use of delicate hydrometers, especially since the men-
iscus of the liquid formed around the stem of the tester renders
an accurate reading somewhat difficult.

The Swedish acid tester can be made more delicate by changes
in one or two directions; by making the bulb larger, thus neces-
sitating an increase in weight, or by making the stem thinner.
By way of comparison it may be stated that the hydrometers
used for determining the specific gravity of the ether-fat solu-
tion in Soxhlet's areometric method of milk analysis have a
stem only 2 mm. in diameter, and the distance of the scale
between .765 and .745 is 70 mm., or 2| inches.

Even if these testers are changed as suggested, their practica-
bility still remains an open question. The action of sulfuric
acid of different strength on milk is very characteristic (75)
and in the hands of experienced operators, is as delicate an
index to the strength of the acid as can be desired, making
rather unnecessary a separate instrument for ascertaining the
correctness of the strength of the acid used in milk testing.

78. The color of the fat column an index to the strength
of the acid used. The strength of the acid is indicated
to a certain extent by the color of the fat which separates
in the neck of the test bottle when milk is tested. If the
directions given for making the test are carefully fol-

68 Testing Milk and Its Products.

lowed, the fat separated out will be of a golden yellow
color. If the fat is light colored or whitish, it generally
indicates that the acid is too weak, and a dark colored
fat, with a layer of black material beneath it, shows that
the acid is too strong, provided the temperature of both
milk and acid is about 70°. [For influence of tempera-
ture, see next paragraph.]

The strength of the acid used in the test is not suf-
ficient at ordinary temperatures of testing to appreciably
dissolve the fat, but a variation in the strength of the
acid or in the temperature of the milk influences the
intensity of the action of the acid on the fat, as shown in
the color of the fat obtained.

The following experiment shows the relation between
the strength of the acid, the temperature of the milk,
and the color of the fat:

First: — From a sample of milk, measure the usual quantity
for testing iuto each of three bottles, A, B and C. Place A in
ice water, and C in warm water, having bottle B at the ordi-
nary temperature. After the bottles have been left for ten min-
utes under these conditions, add the normal quantity of acid
to each and proceed with the test in the ordinary manner.

Second: — Measure some of the same milk into three other
bottles, D, E and F. Into test bottle D pour the usual amount
of rather weak acid; add the same amount of acid of normal
strength (1.82-1.83) to bottle E, and add 17.5 cc. of a still
stronger acid (concentrated sulfuric acid, sp. gr. 1.84), in test
bottle F; complete these tests ill the usual way.

On the completion of the preceding six tests the operator will
notice that the fat in the necks of test bottles A (cold milk] and
D (weak acid] is much lighter colored than that in C (warm
milk] and F (strong acid], and that the color of the fat in B
(normal temperature} and E (normal acid] is somewhere
between that of these two series.

The Babcock Test. 69

79. Influence of temperature on the separation of fat.

The intensity of the action of the sulfuric acid on the
milk is influenced by the temperature of either liquid;
the higher the temperature, the more intense will be the
action of the acid on the solids of the milk. It nray be
noticed that acid from the same carboy will act differently
on milk in summer than in winter time, if the acid and
the milk are not brought to a temperature of about 70°
before testing during both seasons. The temperature of
the liquids may be as low as 40° F. in winter and as high
as 80° F. in summer. This difference of forty degrees
will often have considerable influence on the clearness of
the fat separated, showing white curdy substances and a
light colored fat in winter, or black flocculent specks,
with a dark colored column of fat in summer. Both
these defects can be avoided when the acid is of the
proper strength, by bringing the temperature of the milk
and the acid to about 70° F. before the milk is tested.

The operator should be particularly cautious against
over-heating either milk or acid; so intense an action
may be caused thereby as to force the hot acid out of the
neck of the test bottle when it is added to the milk, thus
spoiling the test and possibly causing an accident.

4. — WATER TO BE USED IN THE BABCOCK TEST.

80. Eain water, condensed steam, or soft water should
be used for the purpose of bringing the fat into the neck
of the test bottles. The surface of the fat column will
then usually be clear and distinct. The foam or bubbles
that sometimes obscure the upper line (meniscus) of the
fat, making indistinct the point from which to measure

70

Testing Milk and Its Products.

it, is generally caused by the action of the acid on the
carbonates in hard water. The carbonic acid gas liber-
ated from hard water by the sulfuric acid is more or less
held by the viscid fat and produces a layer of foam on
its surface. If clean soft water cannot be obtained for
this purpose, hard water may be used by adding a few
drops of sulfuric acid to the water before it is heated,
thus causing the carbonic acid to be driven out of it.
By simply boiling, many hard waters will be rendered
soft and adapted to use in the Babcock test, as most of
the carbonates which cause this foaming are thereby
precipitated.

W

FIG. 25. The Russian test.

If the test has been completed, and
a layer of foam appears over the fat,
it may be destroyed by adding a drop
or two of alcohol. If this is done,
the fat column should be read at once

FIG. 26. Pipette used in

after the alcohol is added, as the tne Russian test.
latter will soon unite with the fat and increase its vol-
ume.

The Bdbcock Test. 71

81. Reservoir for water. When only a few tests are
made at one time, the hot water can be added with the
17.6 cc. pipette. If many tests are made, the water is
more conveniently and quickly filled into the test bottles
by drawing it from a small copper reservoir or tin pail
suspended over the testing machine.1 The flow of water
through a rubber tube connected with the reservoir, is
regulated by means of a pinch cock (Fig. 10). The
water must be hot when added to the test bottles so as to
keep the fat in a melted condition until the readings are
taken. Some turbine testers are now made with a very
convenient water receiver attached to the tester (Figs.
23-24).

The use of zinc or steel oilers, or perfection oil cans
has been suggested, as a handy and rapid method of
adding hot water to the test bottles.

5. — MODIFICATIONS OF THE BABCOCK TEST.

82. The Russian milk test. The same chemical and
mechanical principles applied in the regular Babcock
test, are used in the Eussian milk test, except that in
this case the machine in which the bottles are whirled,
and the bottles themselves, are so constructed that the
latter can be filled with hot water while the machine is
running at full speed, thus saving time and trouble inci-
dent to the stopping of the tester and filling the bottles
by means of a pipette. The milk -measuring pipette
(Fig. 26) and the acid measure used in the Eussian test

i Ordinary tinware rusts very soon when water is left standing in it,
and copper reservoirs are therefore more economical.

Testing Milk and Its Products.

are one-half of the ordinary size, and the test bottles are
made in two pieces, with a detachable narrow graduated
stem (see Fig. 27). The machine is substantially made
of cast iron; it is provided with a very satisfactory speed
indicator which shows at any time the num-
ber of revolutions at which the bottles are
being turned. The accompanying illustra-
tions show the apparatus used in the Eussiau
test. When the directions for operating the
test are followed closely, the results obtained
are accurate and very satisfactory.

83. Bartlett's modification. Bartlett1 pro-
posed a modification of the method of pro-
cedure in the Babcock test, which aims to
simplify the manipulations. 20 cc. of acid
are added, instead of 17.5 cc., and the bottles
filled with the milk-acid mixture are left
standing for not less than five minutes and
then filled with hot water to within the scale;
the bottles are then whirled for five minutes
at the regular rate (52).

In the experience of the authors the modi-

FIG. 27. Test _

bottle used in fication can not always be depended upon to

the Itussian

test. give satisfactory results. When published it

was tried by each of the one hundred students in the
Wisconsin Dairy School; while some of these operators
obtained a clear separation of fat, and results that com-
pared favorably with those made by the regular Babcock
test, others failed to obtain correct results with the
method as modified. It is not known that the modifica-

Maine experiment station, Bull. No. 31 (S. S.).

The Babcock Test.

73

tion lias proved superior to or taken the place of the
regular Babcock test to any extent.1

84. Bausch and Lomb centrifuge. Fig. 28 shows a
form of hand centrifuge which may be used to advantage

by physicians or in pathol-
ogical laboratories for the de-
termination of fat in milk.
The centrifuge is especially
designed for examination of
urine, sputum, blood, etc., but
has been adapted to milk an-
( alysis by the Leffmann & Beam
test, a special form of bottle
(Fig. 29) having been con-
structed for this purpose. The
machine gives sat-
isfactory results by
the Babcock test as
well, provided the
acid used is 1.83-
1.84, or if the bot-
tles containing the
etteGan9d teK acid-milk mix-

FIG. 28. Physician's centrifuge physician's ture be placed in
that may be used for milk testing, centrifuge.

water fQr fiye

"or ten minutes prior to the whirling. As the bottles are
calibrated for only 5 cc. of milk and the neck of the
bottles, with scale, is correspondingly fine, testing milk
with this machine requires some nicety of manipulation
not called for in case of testers constructed for the use of
farmers and dairymen.

i The German dairy chemist Siegfeld in 1899 proposed a modification
of the Babcock test (Molkerei Ztg, Hildesheim, 1899, p. 51), using 2 cc. of
amyl alcohol with the sulfuric acid, and filling up with dilute sulfuric acid
(1:1, sp. gr. 1.5) in one filling, in place of water, after the whirling. A clear
separation of the fat is facilitated by both these changes, but when prop-
erly conducted there is no difficulty whatever in obtaining a clear fat col-
umn in the Babcock test as described in this book, and the modification
will not therefore be likely to be introduced in American factories. It has
become quite generally adopted in North German creameries where the
Babcock test is used.

CHAPTER IV.
CREAM TESTING.

85. Cream may be tested by the Babcock test in the
same manner as milk, and the results obtained are accu-
rate when the necessary care has been taken in sampling
the cream and in measuring the fat. The composition of
cream varies greatly according to the process of cream-
ing, temperature of milk during the creaming, quality

FIG. so.
Students testing dairy products.

and composition of the milk to be creamed, etc. The
cream usually met with in creameries or on the market
(outside of large cities) will contain from 15 to 50 per
cent., or on the average 35 per cent, of fat.1 If 18 grams

iFor average quality of cream furnished at five Connecticut cream-
eries see (202).

Cream Testing. 75

of 25 per cent, cream is measured into an ordinary Bab-
cock test bottle, it follows that there will be 18 x. 25 =4.5
grams (or ~ = 5 cc. ) of pure butter fat in the bottle.
It is shown, however, (p. 38), that the space from 0 to
10 in the neck of these bottles holds exactly 2 cc. The
neck of the milk test bottles will not therefore be large
enough to show the per cent, of fat in a sample of cream
if 18 grams are taken for testing, so that less cream must
be measured out, or special forms of test bottles used (89).
86. Errors of measuring cream. Several factors tend
to render inaccurate the measuring of cream for the Bab-
cock test, and in exact work it is recommended to weigh
the amount taken for a test. If a 17.6 cc. pipette is used
for measuring the cream, it will not deliver 18 grams of
cream, as it will of milk, for the following reasons:

1. The specific gravity of cream is lower than that of
milk; if a certain quantity of milk weighs 1030 Ibs., the
same quantity of cream will weigh from 1020 Ibs. to
below 1000 Ibs., the weight being determined by the rich-
ness of the cream; the more fat the cream contains, the
less a certain quantity of it, e. g., a gallon will weigh.1

2. Cream is thicker (more viscous) than milk at the
same temperatures, and more of it will adhere to the
sides of the measuring pipette than in case of milk. This
is of special importance in testing very rich or sour
cream.

3. In case of separator cream, more or less air will
become incorporated with the cream during the process
of separation. In the ripening of cream, the fermenta-
tion gases developed are held in the cream in the same
way as bread dough holds the gases generated by yeast.

i For specific gravity of cream of different richness, see table on p. 76.

76 Testing Milk and Its Products.

In either case the weight of a certain measure of cream
is diminished.

87. As an illustration of the effect of the preceding
factors on the amount of cream measured out by a Bab-
cock 17.6 cc. pipette, the following weighings of separa-
tor cream are given (columns (a) ). The cream was in
all cases fresh from the separator; it was weighed as de-
livered by the pipette into a Winton cream bottle (91),
and the test proceeded with at once; the specific grav-
ity of the cream was determined by means of a picnome-
ter. The data given are in all cases averages of several
determinations; the samples of cream have been grouped
according to their average fat contents.1

The figures 2 given in columns (b) and (c) are calcu-
lated from the per cent, of fat and total solids in creams
containing different per cents, of fat. Column (c) shows
approximately the corrections to be added to readings of
cream tests when the adhering cream is washed from the
walls of a 17.6 cc. pipette, these washings added to the
test bottle, and the test completed in the usual way.
Weight of fresh separator cream delivered by a 11.6 cc. pipette.

Per cent.

Specific gravity (17.5° C.)

Weight of cream deliv-

Corrections

of fat in

Weighed.

Calculated.

ered, grams.

to be added.

cream.

(a)

(6)

(«)

(b)

(e)}<

10

1.023

1.025

17.9

18.00

0.00

15

1.012

1.020

17.7

17.95

0.04

20

1.008

1.014

17.3

17.84

0.18

25

1.002

1.000

17.2

17.75

0.35

30

.996

1.004

17.0

17.66

0.58

35

.980

.998

16.4

17.56

0.88

40

.966

.993

16.3

17.48

1.19

45

.950

.988

16.2

17.39

1.59

50

.947

.983

15.8

17.30

2.00

1 For influence of condition of cream on the amount measured out
with a 17.6 cc. pipette, see also Bartlett, Maine exp. sta., Bull. 31 (S. S.).

2 Hoard's Dairyman, 1900, p. 355.

Cream Testing. 77

The figures in the table show plainly the variations in
the specific gravity of cream of different richness and
the error of making tests of cream by measuring it with
a 17.6 cc. pipette, especially if the pipette is not rinsed
and the washings added to the test bottle; if the cream
to be sampled is fresh separator cream testing over 30
per cent, less than 17.0 grams of cream will be delivered
into the test bottle, and the results of the reading will
be at least one-eighteenth too low, or about 1.4 per cent,
on a 25 per cent, cream. If the cream is sour, the error
will of course be still greater.

It should be remembered that the specific gravities of
the cream given in the table refer to fresh separator
cream only. Considerable air is incorporated during the
separation, and cream of this kind is therefore lighter
than gravity cream of corresponding fat contents.

88. Avoiding errors of measuring cream. The preced-
ing table shows that a 17.6 cc. pipette in case of cream
containing less than 25 per cent, of fat and fresh from
the separator, will deliver only about 17.2 grams of
cream; it is therefore evident that the pipette to deliver
cream for the Babcock test must be made larger than the
17.6 cc. pipette used in testing milk. Quite satisfactory
results may be obtained in testing such cream by using
an 18 cc. measuring pipette; to avoid the expense and
trouble of using two different pipettes, one for milk and
one for cream, a pipette with two marks on the stem, at
17.6 cc. and 18 cc., has been placed on the market, the
former mark being used when milk is tested, and the
latter for cream.1

i Professor Spillman, in Bull. 32 of Washington experiment station,
recommends the use of a 17.6 cc. pipette for testing cream, the results ob-
tained being corrected by a certain per cent., as shown in a table given in
the bulletin. The table is based on the figures given on p. 76 of this book,
and is therefore only applicable to fresh separator cream.

78 Testing Mm and Its Products.

In testing cream by the Babcock test,
one of two methods may be followed:

First, one of the special forms of cream
test bottles which have been devised is
used; or,

Second, only sufficient cream to be
tested in a regular Babcock milk test
bottle is taken for a sample.

89. Cream test bottles. Three special
forms of bottles have been devised for
testing samples of cream by the Babcock
test; two of these were suggested by
Bartlett of Maine,1 in 1892; one with a
long detachable neck designed for test-
ing very rich cream (up to 35 per cent,
fat), and the other with a neck widened
into a bulb in the middle so as to allow
a large quantity of fat to be measured.
The former kind of cream bottle never
met with favor among operators; its neck
was too long to be used in the ordinary
centrifugal machines, and was not at-
tached until the base portion, containing
the cream, acid and first filling with
water, had been whirled.

90. The bulb-necked cream bottles (Fig.
31), allow the testing of cream contain-

FIG. 31. The bulb- ing 23 or 25 per cent, of fat, the usual

necked cream

test bottle. quantity of cream (18 grams) being

measured out. The neck is graduated from 0 to 23 per

i Maine experiment station, bulletins 3 and 4 (second series).

Cream Testing.

79

cent., and in some cases to 25 per cent., the graduation
extending both below and above the bulb. This is some-
times an inconvenience, as the water
must be added carefully so that the lower
end of the column of fat will always
come below the bulb, in the graduated
part of the neck, and not in the bulb
itself. Especially in case of beginners,
tests are often lost when this bottle is
first used, for the reason given; the
operator will, however, soon learn to add
the proper amount of hot water to float
the fat to some point within the scale.
It is recommended to fill these bottles
with the first portion of hot water to just
above the bulb, so that one can see how
much water to add the second time in
order to bring the fat within the scale.

Each division of the scale on these
cream bottles represents two- tenths of
one per cent, of fat, as in case of the milk
test bottles.

91. The Winton cream bottle. The
cream test bottle devised by Winton,1
(Fig. 32), has a neck of the usual length,
and sufficiently wide to measure 30 per
cent, of fat. The scale of the neck is di-

FIG. 32. The Win-

vided into one-half per cents., but read- ton cream bottle,
ings of a quarter of a per cent, can easily be estimated.
Determinations of fat in cream accurate to a quarter of a

i Connecticut experiment station (New Haven), Bull. No., 117: report
1894, p. 224.

80 Testing Milk and Its Products.

per cent, are sufficiently exact for most commercial pur-
poses, e. g., in creameries, and this form of cream bottle
will be found very convenient in making tests of composite
samples of cream.

92. Use of milk test bottle. Cream may be tested by
emptying a 17.6 cc. pipetteful of the sample into two or
more milk test bottles, dividing the amount about equally
between the bottles and filling the pipette with water once
or twice, which is then in turn divided about equally
between the test bottles; the per cent, of fat in the cream
is found by adding the readings obtained in each of the
bottles. Milk and water must be mixed before the acid
is added.

This method does away with the error incident to the
adhesion of cream to the side of the pipette, but not that
due to the low specific gravity of the cream, and the re-
sults obtained will therefore be too low. The dilution of
the cream with water in the test bottles not only makes
it possible to bring into the bottle all the cream measured
out, but also insures a clear test. If ordinary cream is
mixed with the usual quantity of sulfuric acid used in
the Babcock test, a dark-colored fat will generally be
obtained, while the cream diluted with an equal or twice
its volume of water, when mixed with the ordinary
amount of acid, will give a light yellow, clear column of
fat, which will allow of a very distinct and sharp read-
ing.

The number of bottles to be used -for testing a sample
of cream by this method must be regulated by the rich-
ness of the cream. If the sample probably contains 20
per cent, or more, a pipetteful should be divided nearly

Cream Testing. 81

equally between three milk test bottles, and two-thirds
of a pipetteful of water is added to each bottle. If the
cream contains less than 20 per cent, of fat, it will only
be necessary to use two milk test bottles, dividing the
pipetteful between these, and adding one-half of a pipette-
ful of water to each bottle.

By using cream test bottles (89), more accurate tests
may be obtained in case of cream containing as much as
25 per cent, of fat, by dividing one pipetteful between
two bottles, rinsing half a pipette of water into each one,
than by adding all the cream to one bottle without rins-
ing the pipette, for reasons apparent from what has been
said in the preceding.

93. Use of a 5 cc. pipette. When the cream is in good
condition for sampling, satisfactory results can be ob-
tained by the use of a 5 cc. pipette, provided great care
is taken in mixing the cream before sampling; 5 cc. of
cream are measured into a milk test bottle, and two
pipettefuls of water are added. In this way all the cream
in the pipette is easily rinsed into the test bottle. The
readings multiplied by ^ =3.6 wil1 give the per cent, of
fat in the cream. If the specific gravity of the cream
tested varies appreciably from 1, corrections should be
made accordingly; e. g., if the specific gravity is 1.02;
the factor should read 505 =3. 53; if .95, ^=3.79, etc.

94. Weighing the cream. For the reasons already given
it is always to be preferred to weigh the cream in the test
bottles when accurate tests are required. When a small,
delicate balance is used, this can be done quite rapidly.
Either of the scales shown in the accompanying illustra-
tion (fig. 33), will be found useful and sufficiently accu-

6

82 Testing Milk and Its Products.

rate for this purpose; a small scale of this kind is also con-
venient and helpful in testing cheese, butter and con-
densed milk, in determining the strength of sulfuric
acid, and the accuracy of test bottles and pipettes (q. v. ).
In testing cream by weight, the test bottle is first
weighed empty, and again when 5 to 10 cc. of cream
have been measured into it; the difference between the
two weights gives the weight of cream taken for the test.
If the cream contains less than 30 per cent, of fat, the
regular milk test bottle can be used for testing the
cream, if not much more than 5 grams are weighed out;
if more cream is taken, or if this is richer than 30 per
cent., it is advisable to use the cream bottle.

FIG. 33. Scale used for weigh- FIG. 34. Beebe and Spill-

ing cream, chee?e, etc., in the man cream weighing scale

Babcock test.

The operator should be careful in weighing the cream
not to spill it on the outside of the test bottle. Suffi-
cient water is added to the bottle to make the total
volume about 15 cc. The usual quantity of acid (17.5 cc. )
is then added, and the test completed in the ordinary
manner. The reading of the amount of fat in the neck
of the test bottle in this case does not show the correct
per cent, of fat in the cream, because less than 18 grams
were weighed out. The per cent, of fat in the cream
tested is obtained by multiplying the reading by 18,

Cream Testing.

83

and dividing the product by the weight of the cream
taken.

Example: Weight of cream tested, 5.2 grams; reading of
columns of fat tH.S, 2 '4. 7, average 4.75; percent, of fat in the

cream

5.2

b-

c -

The weighing of cream and the reading of the fat col-
umn must be made very carefully; a division of one-
tenth on the neck of the test bottle has a
value of over three-tenths of one per cent.
of fat when 5 grams of cream are tested,
_ r and six-tenths of one per cent, if only 3
grams of cream are weighed out. The
reading is rendered more accurate and
certain if a number of tests of a sample
are made, at least two or three, and the
results averaged.

The accompanying illustration (fig.
35), shows the proper method of reading
the fat column in cream tests; readings
are taken from a to &, not to d or to c.1

95. No special precautions other than
FIG. 35. Measur- those required in testing milk have been

ing the fat column

in the neck of a found necessary in testing cream, except

cream bottle. Read-

a. —

or to c-

^^ ^ *s some^mes advisable not to whirl
the test bottles in the centrifuge at once
after mixing, but to let the cream-acid mixture stand for
awhile, until it turns dark colored. At first, the mix-
ture of cream and acid is much lighter colored than that
of milk and acid, owing to the smaller amount of solids
not fat contained in the cream.

iThe size of the meniscus is magnified in the cut.

84 Testing Milk and Its Products.

The liquid beneath the fat in a completed test of
cream is sometimes milky, and the fat appears white
and cloudy, making an exact reading difficult. Such
defects can usually be overcome by placing the test bot-
tles in hot water for about 10 minutes previous to the
whirling, or by allowing the fat to crystallize (which is
done by cooling the bottles in cold water after the last
whirling) and remelting it by placing the bottles in hot
water.

96. The error due to the expansion of the fat in case
of excessively hot turbine testers having no openings in
the cover as mentioned on p. 36, is especially noticeable
in cream testing, where it may amount to one per cent,
or more. In order to obtain correct results with such
testers, the hot cream test bottles must be placed in
water at about 140° F. for ten minutes before the results
are read off.

CHAPTEE V.
BABCOCK TEST FOR OTHER MILK PRODUCTS.

97. Skim milk. Each division on the scale of the neck
of the regular Babcock test bottle represents two-tenths
of one per cent. (44). When a sample of skim milk or
butter milk containing less than this per cent, of fat is
tested, the estimated amount is expressed by different
operators as one-tenth, a trace, one-tenth trace, or one- to
five-hundredths of one per cent. Gravimetric chemical
analyses of skim milk have shown that samples which
give only a few small drops of fat floating on the water
in the neck of the test bottle, or adhering to the side of
the neck, generally contain one-tenth of one per cent, of
fat, and often more. Samples of skini milk containing
less than one-tenth of one per cent, of fat are very rare,
and it is doubtful whether a sample of separator skim
milk representing a full run of say 5,0001bs. of milk, has
ever shown less than five-hundredths of one per cent, of
fat. Under ordinary factory conditions, few separators
will deliver skim milk containing under one-tenth of one
per cent, of fat, when the sample is taken from the whole
day's run. This must be considered a most satisfactory
separation.1

98. The reason why the Babcock test fails to show all
the fat present in skim milk must be sought in one or
two causes: a trace of fat may be dissolved in the sulfuric
acid, or owing to the minuteness of the fat globules of

i For comparative analyses of separator skim milk by the gravimetric
method and by the Babcock test, see Wis. exp. station, bull. 52 and rep.
XVII, p. 81.

86 Testing Milk and Its Products.

such milk they may not be brought together in the neck
of the bottles at the speed used with the Babcock test.
The latter cause is the more likely explanation. If a drop
of the dark liquid obtained in a Babcock bottle from a
test of whole .milk, be placed on a slide under the micro-
scope, it will be seen that a fair number of very minute
fat globules are found in the liquid. These globules are
not brought into the column of fat in the neck of the bot-
tle by the centrifugal force exerted in the Babcock test,
unless the bottles are whirled in a turbine tester in which
they are heated to 200° F. or higher, see (71); the loss
of the fat contained in these fine globules is compensated
for, in the testing of whole milk, by a liberal reading of
the column of fat separated out, the reading being taken
from the lower meniscus of the fat to the top of the upper
one (see p. 35) ; in some separator skim milk, on the other
hand, not enough fat remains to completely fill the neck,
and the apparent result of the reading must therefore be
increased by from five-hundredths to one-tenth of one
per cent, or the sample tested in a double-necked skim
milk bottle.

It follows from what has been said that tests of skim
milk showing no fat in the neck of the test bottles on
completion of the test, generally indicate inefficient work
of the centrifugal tester or of the operator, or of both.
The test should be repeated in such cases, using more
acid and whirling for full four minutes.

In order to bring as much fat as possible into the neck
of the bottles in testing skim milk, it is advisable to add
somewhat more acid than when whole milk is tested, viz.,
about 20 cc., and to whirl the bottles at full speed for four

BabcocJc Test for other Milk Products.

87

to five minutes, keeping the tester as hot as possible the
whole time.1 The readings must be taken as soon as the
whirling is completed, as owing to the contraction of the
liquid by cooling, the fat otherwise adheres
to the inside of the neck of the test bottle
as a film of grease which cannot be meas-
ured by the scale.

99. The double-necked test bottle, (Fig.
36), suggested by one of us,2 is made espe-
cially for measuring small quantities of fat
and gives most satisfactory results in testing
skim milk and butter milk. Each division
of the scale in these bottles represents five-
hundredths of one per cent., and the marks
are so far apart that the small fat column
can be easily estimated to single hundredths
of one per cent. In the first forms, now
out of use, the neck was graduated to hun-
dredths of one per cent.

The value of the divisions of the scale on
the double-necked test bottles has been a FIG. 36. The

double-necked

subject of considerable discussion, and van- skim miik bot-
tle (sometimes

ous opinions have been expressed whether called the Chi-
ron or B. & W.
they show one-tenth or one-twentieth (.05) bottie.)

of one per cent, of fat. By calibration with mercury the
value of the divisions will be found to be .05 or one-
twentieth of one per cent., but as shown above, the
results obtained in using the bottles for thin separator
skim milk often come at least .05 per cent, too low, so
that, practically speaking, each division may be taken to

1 See Wis. exp. station, report XVII, p. 81.

2 Farrington, and constructed by Mr. J. J. Nussbaumer, of Illinois.

88

Testing Milk and Its Products.

show one-tenth of one per cent., if the fat fills only one
division of the scale or less.1

The double-necked bottle is very convenient for the
testing of separator skini milk, thin butter milk and
whey. The milk, acid and water are added to the bottle
through the large side-tube; the mixing of milk and acid
must be done with great care, so that none of the con-
tents is forced into the fine measuring tube and lost; it is
best to add half of the acid first and mix it with the milk,
and then add the rest. When the fat is in the lower end
of the measuring tube, it can be forced into the scale by
pressing with the finger on the top of the
side tube.

In placing the double-necked bottle in
the tester they should be put with the
filling tube toward the center so as to
avoid any of the fat being caught be-
tween this tube and the side of the bot-
tle when it resumes a vertical position.
This test bottle is more fragile and ex-
pensive than the ordinary Babcock bot-
tles, and must be carefully handled; it
has recently been made of heavier glass
and this form is to be highly recom-
mended.2

100. The double-sized skim milk bottle is
of no particular value. It is difficult to
obtain a thorough mixture of the milk and the acid in

i Wis. experiment station, bull. 52; Penna. experiment station, report
1896, p. 221.

2 During the past year a copper double-necked test bottle with a detach-
able graduated glass neck was designed and tried by one of us (F.), but no
special advantages over the glass bottle has so far been found for it.

FIG 37 Wagner
skim milk bottle.

BabcocJc Test for other Milk Products. 89

these bottles, and the tests invariably come too low, more
so than with the regular Babcock bottles or the double -
necked skim milk bottles, for reasons that are readily
seen.

101. Buttermilk and whey. The testing of buttermilk or
whey by the Babcock test offers no special difficulties, and
what has been said in regard to tests of separator skim
milk is equally true in case of these by-products, Whey
contains only a small quantity of solids not fat, viz., less
than 7 per cent. (27), and the mixing with acid and the
solution of the whey solids therein is therefore readily
accomplished; the acid solution is of alight reddish color,
turning black but very slowly.

102. Cheese. Cheese can be easily tested by the Bab-
cock test if a small scale (fig. 33) is at hand for weighing
the sample; the results obtained will furnish accurate
information as to the amount of fat in the cheese, provided
good judgment and exactness are used in sampling and
weighing the cheese. The following method of sampling
cheese is recommended: *

u Where the cheese can be cut, a narrow wedge reach-
ing from the edge to the center of the cheese will more
nearly represent the average composition of the cheese
than any other sample. This may be cut quite fine, with
care to avoid evaporation of water, and the portion for
analysis taken from the mixed mass. When the sample
is taken with a cheese trier, a plug taken perpendicular
to the surface, one-third of the distance from the edge to
the center of the cheese, will more nearly represent the
average composition than any other. The plug should

i U. S. Dept. of Agriculture, Chemical Division, bull. No. 46, p. 37.

90 Testing Milk and Its Products.

either reach entirely through or only half way through
the cheese.

"For inspection purposes the rind may be rejected, but
for investigations, where the absolute quantity of fat in
the cheese is required, the rind should be included in the
sample. It is well, when admissible, to take two or three
plugs on different sides of the cheese and after splitting
them lengthwise with a sharp knife, take portions of each
for the test."

103. When a satisfactory sample of the cheese has been
obtained, about 5 grams are weighed into a milk test
bottle, or a larger quantity may be used with a cream
test bottle. The test bottle is first weighed empty, and
again after the pieces of cheese have been added. About
15 cc. of warm water is added to the cheese in the test
bottle, and this is shaken occasionally until the cheese
softens and forms a creamy emulsion with the water.
A few cc. of acid will aid in this mixing and disintegra-
tion. When all lumps of cheese have disappeared in
the liquid, the full amount of acid is added, and the test
completed in the ordinary manner.

The per cent, of fat in the cheese is obtained by multi-
plying the reading of the fat column by 18 and dividing
the product by the weight of cheese added to the test
bottle. The weighing of the cheese and the reading of
the fat must be done with great care, since any error
introduced is more than trebled in calculating the per
cent, of fat in the cheese.

104. Condensed milk. The per cent, of fat in un-
sweetened condensed milk can be obtained by weighing
8 grams into a test bottle and proceeding in exactly the

BabcocTc Test for other Milk Products. 91

same way as given under testing of cheese. It is not
necessary to add ammonia or to warm the condensed
milk in the test bottles, since the solution of this in
water is readily effected without any outside agency.
Enough water should be added to make the total volume
of liquid in the bottles 15-18 cc.

If a scale is not available for weighing the sample,
fairly accurate results may be obtained by diluting the
condensed milk with water (1:3), and completing the
test in the ordinary manner. When this is done, the
results must be corrected for the dilution which the
sample received.

105. Sweetened condensed milk. This presents pecul-
iar difficulties, whether it is to be tested by the Babcock
test or by chemical analysis. It may, however, be
readily tested by the Babcock test by introducing cer-
tain changes in the manipulation of the test as worked
out by one of us (F).1

A brief description of the manipulations adopted will
explain the method that has proved satisfactory.

About sixty grams of condensed milk are weighed
into a 200 cc. graduated flask; to this 100 cc. of water
are added and the solution of the condensed milk
effected. The flask is then filled to the mark with
water and after mixing thoroughly, a 17.6 cc. pipette
full is measured into a Babcock test bottle. About
three cc. of the sulfuric acid commonly used for test-
ing milk are then added and the milk and acid mixed
by shaking the bottle vigorously. The milk is curdled
by the acid, and the curd and whey separated somewhat.

(i) 17th Annual Report of Wis. Expt. Station,*pp. 86-89.

92 Testing Milk and Its Products.

In order to make this separation complete and to com-
pact the curd into a firm lump, the test bottle is whirled
for about six minutes at a rather high speed (1,000 rev.)
in a steam-heated turbine centrifuge.

The chamber in which the bottles are whirled ought
to be heated to about 200° F. This can be done either
by the turbine exhaust steam which leaks into the test-
bottle chamber of some machines, or by means of a
valve and pipe which will allow steam to be turned
directly into the test bottle chamber. After this first
whirling the test bottles are taken from the centrifuge
and by being careful not to break the lump of curd
nearly all the whey or sugar solution can be poured out
of the neck. Ten cc. of water are then poured into
the test bottle and the curd is shaken up with it so as to
wash out more of the sugar. Three cc. of acid are
now added as before and the test bottle whirled a second
time in the centrifuge. The whey is decanted again and
this second washing removes so much of the sugar that
what remains will not interfere with testing in the usual
way. The curd remaining in the test bottle after the
second washing is shaken up with ten cc. of water and
to this water emulsion of the curd the usual amount,
17.5 cc. of sulfuric acid is added and the test completed
in the same way as milk is tested. The amount of fat
finally obtained in the neck of the test bottle is calcula-
ted to the weight of condensed milk taken.

Five brands of sweetened condensed milk were exam-
ined by this process, at least four determinations being
made of each sample. The fat separated was clear and
the final results satisfactory.

CHAPTEE VI.
THE LACTOMETER AND ITS APPLICATION.

106. The Quevenne lactometer. This instrument (see
Fig. 38, next page) consists of a hollow glass cylinder
weighted by means of mercury or fine shot so that it will
float in milk in an upright position, and provided with a
narrow stem at its upper end, inside of which is found a
graduated paper scale. In the better forms, like the Que-
venne lactometer shown in the figure, a thermometer is
melted into the cylinder, with its bulb at the lower end
of the lactometer and its stem rising above the lactometer
scale.

The lactometer is used for the determination of the
specific gravity of milk. The term specific gravity means
the weight of a certain volume of a solid or a liquid sub-
stance compared with the weight of the same volume of
water at 4° C. (39.2° Fahr.); for gases the standard of
comparison is air or hydrogen. If the milk which a can
will hold weighs exactly 103.2 fibs., this can will hold a
smaller weight of water, say 100 Ibs., as milk is heavier
than water ; the specific gravity of this milk will then
be Jff02- = 1.032.

The specific gravity of normal cows' milk will vary in
different samples between 1.029 and 1.035 at 60° F., the
average being about 1.032.

107. The lactometer enables us to determine rapidly
the relative weight of milk and water. Its application
rests on well-known laws of physics: When a body
floats in a liquid, the weight of the amount of liquid

94

Testing Milk and Its Products.

which it replaces is equal to the weight
of the body. It will sink further into a
light liquid than into a heavy one, be-
cause a larger volume of the former will
be required to equal the weignt of the
body. A lactometer will therefore sink
deeper into milk of a low specific grav-
ity than into milk of a high specific
gravity.

The scale of the Quevenne lactometer
is marked at 15 and 40, and divided into
25 equal parts, with figures at each five
divisions of the scale. The single divis-
ions are called degrees. The 15 degree
mark is placed at the point to which the
lactometer will sink when lowered into a
liquid of a specific gravity of 1.015, and
the 40 degree mark at the point to which
it will sink when placed in a liquid of a
specific gravity of 1.040. The specific
gravity is changed to lactometer degrees
by multiplying by 1000 and subtracting
1000 from the product.

Example: Given, the specific gravity of a
sample of milk is 1.0345; corresponding lacto-
meter degree, 1.0345x1000-1000=34.5.

Conversely, if the lactometer degree
is known, the corresponding specific
gravity is found by dividing by 1000
and adding 1 to the quotient (34. 5 ~ 1000
= .0345; .0345-j-l = 1.0345). mder(ii2).

FIG. 38

Quevenne
a ti°n c"f

The Lactometer and its Application. 95

108. Influence of temperature. Like most liquids, milk
will expand on being warmed, and the same volume will,
therefore, weigh less when warmed than before; that is,
its specific gravity will be decreased. It follows then
that a lactometer is only correct for the temperature at
which it is standardized. If a lactometer sinks to the
32-mark in a sample of milk of a temperature of 60° F.,
it will only sink to, say 33, if the temperature of the
milk is 50° F., and will sink farther down, e. g., to 31,
if the temperature is 70° F. Lactometers on the market
at present are generally standardized at 60° F., and to
show the correct specific gravity the milk to be tested
should first be warmed (or cooled, as the case may be)
to exactly 60° F. As this is a somewhat slow process,
tables have been constructed for correcting the results
for errors due to differences in temperature (see Appen-
dix, Table V).

109. As the fat content of a sample of milk has a
marked influence on its specific gravity at different tem-
peratures, the co -efficient of expansion of fat differing
greatly from that of the milk serum, the table cannot
give absolutely accurate corrections for all kinds of milk,
whether rich or poor. But the errors introduced by the
use of one table for any kind of whole milk within a
comparatively small range of temperature, like ten de-
grees above or below 60°, are too small to have any im-
portance outside of exact scientific work, and in such,
the specific gravity is always determined by means of a
picnometer or specific gravity bottle, at the temperature
at which this has been calibrated. In taking the spe-
cific gravity of a sample of milk by means of a lacto-

96 Testing Milk and Its Products.

meter, the milk is always warmed or cooled so that its
temperature does not vary ten degrees either way from
60° F.

110. The temperature correction table for whole milk,
given in the Appendix shows that if, e. g., the specific
gravity of a sample of milk taken at 68° F. was found
to be 1.034, its specific gravity would be 1.0352 if the
milk was cooled down to 60°. If the specific gravity
given was found at a temperature of 51°, the corrected
specific gravity of the milk would be 1.0329.

In practical work in factories or at the farm, sufficiently
accurate temperature corrections may generally be made
by adding . 1 to the lactometer reading for each degree
above 60° F., and by subtracting .1 for each degree below
60°; e. g., if the reading at 64° is 29.5, it will be about
29.5 + .4=29.9 at 60° F.; and 34.0 at 52° F. will be
about 34.0 -.8 =33. 2 at 60° F. The table in the Appen-
dix gives 33.0 as the corrected figure in both cases.

The scale of the thermometer in the lactometer should
be placed above the lactometer scale so that the tempera-
ture may be read without taking the lactometer out of
the milk; this will give more correct results, will facil-
itate the reading and save time.

111. N. Y. Board of Health lactometer. In the East, and
among city milk inspectors generally, the so-called New
York Board of Health lactometer is often used. This
does not give the specific gravity of the milk directly,
as is the case with the Quevenne lactometer, but the scale
is divided into 120 equal parts, known as Board of Health
degrees, the mark 100 being placed at the point to which
the lactometer sinks when lowered into milk of a. specific

The Lactometer and its Application. 97

gravity of 1.029 (at 60° F. ); this is considered the lowest
limit for the specific gravity of normal cows' milk. The
zero mark on the scale shows the point to which the lac-
tometer will sink in water; the distance between these
two marks is divided into 100 equal parts, and the scale
is continued below the 100 mark to 120. As 100° on the
Board of Health lactometer corresponds to 29° on the
Quevenne lactometer, the zero mark showing in either
case a specific gravity of 1, the degrees on the former
lactometer may easily be changed into Quevenne lacto-
meter degrees by multiplying by .29. To further aid in
this transposition, table III is given in the Appendix,
showing the readings of the two scales between 60° and
120° on the Board of Health lactometer.

112. Reading the lactometer. For determining the spe-
cific gravity of milk in factories or private dairies, tin
cylinders, 1^ inches in diameter and 10 inches
high, with a base about four inches in diame-
ter, are recommended (see Fig. 38); another
form of specific gravity cylinders, in use in
chemical laboratories, is shown in Fig. 39.
The cylinder is filled with milk of a tempera-
ture ranging between 50° and 70° F., to
within an inch of the top, and the lactometer
is slowly lowered therein until it floats; it is
left in the milk for about half a minute before
lactometer and thermometer readings are
taken, both to allow the escape of air which
has been mixed with the milk in pouring it
preparatory to the specific gravity determina-
tion, and to allow the thermometer to adjust cylinder.

itself to the temperature of the milk. The lactometer

7

98 Testing Milk and Its Products.

should not be left in the milk more than a minute before
the reading is taken, as cream will very soon begin to
rise on the milk, and the reading, if taken later, will be
too high, as the bulb of the lactometer will be floating
in partially skimmed milk (23). In reading the lac-
tometer degree, the mark on the scale plainly visible
through the upper portion of the meniscus of the milk
should be noted. Owing to surface tension the milk in
immediate contact with the lactometer stem will rise
above the level of the surface in the cylinder, and this
must be taken into consideration in reading the degrees.
There is no need of reading closer than one-half of a lac-
tometer degree in the practical work of a factory or a
dairy.

113. Time of taking lactometer readings. The specific
gravity of milk should not be determined until at least
three hours after the milk has been drawn from the udder,
as too low results are otherwise obtained (RecknageV s
phenomenon).1 The cause of this phenomenon is not
definitely understood; it may come from the escape of
gases in the milk, or from changes occurring in the me-
chanical condition of the nitrogenous components of the
milk. The results obtained after three or four hours will
as a rule come about one degree higher than when the
milk is cooled down directly after milking and its specific
gravity then determined.

114. Influence of bi-chromate on the lactometer reading.
When potassium bi-chromate is added to milk samples
to preserve them from souring (188), the specific gravity

i Milchzeitung 1883, 419; Bulletin No. 43, Chem, Div., U.S. Department
Of Agriculture, p. 191; Analyst 1894, p. 76,

The Lactometer and its Application. 99

of the milk is thereby increased; with the quantity usu-
ally added (•§• gram to a pint of milk) the increase amounts
to about 1 lactometer degree, and this correction of lacto-
meter readings should be made with milk samples pre-
served in this manner. To avoid this error, Dr. Eichloff 1
recommends using a solution of bi-chrornate in water
(43 grams to 1 liter), the specific gravity of which is
1.032, or similar to that of average milk; 5 cc. of this so-
lution is required for a pint of milk. No correction is
necessary for the dilution with this small amount of liquid
preservative.

115. Cleaning of lactometer. The lactometer should be
cleaned directly after using, by rinsing with cold water;
it is then wiped dry with a clean cloth and placed in the
case.

CALCULATION OF MILK SOLIDS.

116. A number of chemists have prepared formulas for
the calculation of milk solids when the fat content and
the specific gravity (lactometer reading) of the milk are
known. By careful work with milk tester and lacto-
meter it is possible by means of these formulas to deter-
mine the composition of samples of milk with consider-
able accuracy outside of, as well as in chemical laborator-
ies. As the complete formulas given by various chemists
(Behrend and Morgen, Clausnitzer and Mayer, Fleisch-
mann, Hehner and Kichmond, Eichmond, Babcock)2 are
very involved, and require rather lengthy calculations,
tables facilitating the figuring have been prepared. The
formulas in use at the present time, in this country and

1 Technik der Milchpriifung, p. 98.

2 Agricultural Science, vol. Ill, p. 139.

100 ' Testing Milk and Its Products.

abroad, are those proposed by Fleischmann, Hehner and
jBichmond, and Babcock. Babcock's formula is the one
! generally taught in American dairy schools and is there-
fore given here; it forms the foundation of table VI for
solids not fat in the Appendix.

By the use of these tables the percents of solids not fat
may be found, corresponding to lactometer readings
from 26 to 36, and to fat contents from 0 to 6 per cent.
The formula, as amended in 1895, 1 is as follows, 8 being
specific gravity and / the percent of fat in the milk:

(100 ^ ^f \
100-1.0753 Hf-V^100^) 2.5

The derivation of this formula is explained in the re-
port referred to.

117. Short formulas. The tables made up from this
formula, giving the percentages of solids not fat corres-
ponding to certain per cents, of fat and lactometer read-
ings, are given in the Appendix. A careful examination
of the same discloses the fact that the per cent, of solids
not fat increases uniformly at the rate of .25 percent, for
each lactometer degree, and .02 per cent, for each per
cent, of fat. This relation is expressed by the following
simple formulas:

Solids not fat = J L + .2 f

Total solids = J L + 1.2 f,

L being the lactometer reading at 60° F. (specific gravity
X 1000 — 1000), and / the per cent, of fat in the milk.

Rule: a, To find the per cent, of solids not fat in milk, add
two-tenths of the per cent, of fat to one-fourth of the lactometer
reading, and

b, To find total per cent, of solids in milk, add one and two-
tenths times per cent, of fat to one-fourth of the lactometer
reading.

i Wisconsin experiment station, twelfth report, p. 120.

The Lactometer and its Application. id

These formulas and rules are easily remembered and
can be quickly applied without the use of tables. The
results obtained by using them do not differ more than
.04 per cent, from those of the complete formula for
milks containing up to 6 per cent, of fat, and may be
safely relied upon in practical work.

ADULTERATION OF MILK.

118. Methods of adulteration. The problem of determin-
ing whether or not a sample of milk is adulterated be-
comes an important one in the work of milk inspectors
and dairy- and food chemists. Managers of creameries
and cheese factories are also sometimes interested in
ascertaining possible adulterations in case of some
patron's milk, although at present, since the general
introduction of the Babcock test in factories and the pay-
ment for the milk on the basis of the amount of butter
fat delivered, the temptation to water or skim the milk
has been largely removed. In the city milk trade, espe-
cially in our larger cities, watered or skimmed milk is
still frequently met with, in spite of the vigilance of their
milk inspectors or officers of the city boards of health.

When the origin of a suspected sample of milk is
known, a second sample should always be taken on the
premises by or in the presence of the inspector, and the
composition of the two samples compared. If the sus-
pected sample is considerably lower in fat content than
the second, so-called control-sample, and has a normal
per cent, of solids not fat, it is skimmed; if the solids not
fat are below normal, it is watered; and if both these
percentages are abnormally low, the sample is most
likely both watered and skimmed (123).

102 Testing Milk and Its Products.

119. Latitude of variation. In order to determine
whether or not a sample of milk is skimmed or watered,
or both skimmed and watered, the per cents of fat and of
solids not fat in the sample must be ascertained, and if a
control -sample can be secured, these determinations for
both samples compared. The proper latitude to be
allowed for the natural variation in the composition of
milk differs according to the origin of the milk; in case
of milk from single cows, the variations in fat content
from day to day may exceed one per cent., although under
ordinary conditions the per cent, of fat in most cows' milk
will not vary that much. The content of solids not fat
is more constant, and rarely varies one-half of one per
cent, from day to day with single cows. Cows in heat or
sick cows may give milk differing considerably in com-
position from normal milk.1

120. Mixed herd milk is of comparatively uniform com-
position on consecutive days, and as most milk offered
for sale or delivered to factories is of this kind, the task
of the milk inspector is made considerably easier and
more certain on this account. Daily variations in herd
milk beyond one per cent, of fat and one-half per cent, of
solids not fat, are suspicious and may be taken as fairly
conclusive evidence of adulteration. This is especially
true in case the control-sample shows a comparatively
low content of fat or solids not fat (155).

121. Legal standards. Where a control -sample cannot
be taken, the legal standards of the various states for fat
or solids in milk are used as a basis for calculating the

i Blythe, Foods, their Composition and Analysis, London, 1882, p. 246
et seq.

The Lactometer and its Application. 103

extent of adulteration of a sample of milk. A list of
legal standards for milk in this country and abroad is
given in the Appendix. These standards determine the
limits below which the milk offered for sale within the
respective states must not fall. Legally it matters not
whether a sample of milk offered for sale has been
skimmed or watered by the dealer or by the cow; in the
latter case, the cows producing the milk are of a breed
or a strain that has been bred persistently for quantity
of milk, without regard to its quality. In most states
the legal standard for the fat content of milk is 3 per
cent., and for solids not fat 9 per cent. There are, how-
ever, cows which normally produce milk containing only
2.5 to 2.8 per cent, of fat, and less than 8.5 per cent,
solids not fat. Such milk cannot therefore be legally
sold in most states in the Union, and the farmer offering
such milk for sale, even if he does not know the compo-
sition of the milk produced by his cow, is as liable to
prosecution as if he had directly watered the milk. By
mixing the milk of several cows, the chances are that the
mixed milk will contain more fat and solids not fat than
called for by the legal standard; if such should not be
the case, cows producing richer milk must be added to
the herd so as to raise the quality of the herd milk up to
the legal standard.

122. The specific gravity of the milk solids. A calcula-
tion of the specific gravity of the milk solids is of consid-
erable assistance in interpreting the results of analyses
of suspected milk samples. The milk solids vary but
slightly in specific gravity, viz., between 1.25 and 1.34,
the richer milks having solids of low specific gravities.

104 Testing Milk and Its Products.

The specific gravity of the solids of milk is calculated by
means of Fleischmann' s formula

t

S =

100 s-100
t —

s

8 being the sp. gr. of the milk solids, s that of the milk,
and t the total solids of the milk.
Example: A sample of milk has been found to contain 13 0

(103.2-
1.032

per cent, of solids, sp. gr. 1.032; then 100x}0L^~100=3. 101; 13.0

-3.101=9.899; ^=1.31 = the specific gravity of the milk solids.

The specific gravity of the solids does not change if
the milk is watered, while it is increased when the milk
is skimmed. If a sample of milk of the composition
given in the preceding example had been watered so as
to reduce the solids to 11.7 per cent, and the specific
gravity to 1.0291 (as would be the case when 10 per cent,
of water was added), we would again have, by calcula-
tion as above, S = 1.31. If, on the other hand, the milk
was skimmed so as to reduce the solids to 11.7 per cent.,
thereby increasing the specific gravity of the milk to,
say 1.035, we would have by substituting these values
in the preceding formula, 8=1.41, showing conclusively
that the milk had been skimmed.

Addition of skim milk to whole milk would have the
same effect as skimming, as regards the composition of
the latter, and the specific gravity of its solids.

The specific gravity of pure butter fat at 60° F. is .93,
and of the fat-free milk solids 1.5847 (Fleischmann).
The solids of skim milk have a specific gravity of 1.56.
Samples of whole milk, the solids of which have a spe-

The Lactometer and its Application. 105

cific gravity above 1.34 are suspicious, aud a specific
gravity over 1.40 is conclusive evidence of skimming.

To facilitate the calculation of the specific gravity of
milk solids, table IV is given in the Appendix, showing
at a glance the value of 100s~ 10° for specific gravities be-
tween 1.019 and 1.0369. An example will readily illus-
trate the use of the table.

Example: A sample of milk has a specific gravity of 1.0343
and contains 12.25 per cent, solids. In table IV, we find in the
horizontal line beginning with 1.034 under the column headed
0.0003, the figure 3.316, which is the value for 10° s~100 when
s=i.0343. Introducing this value and that of the total solids
in the formula, the calculation is 12.25—3.316=8.934; 12.25-=-
8.934=1.37. The specific gravity of the solids in this case
therefore is 1.37.

123. To recapitulate. Adulteration of milk by water-
ing or skimming or both may be established by a com-
parison of the composition of the suspected sample with
that of a control -sample, or if none such can be obtained,
with the legal standards. If the components of the two
samples vary appreciably, the milk has been adulterated,
and the character of the adulteration is shown from the
following statement:

// the analysis of the suspected sample
shows the milk is

sp. gr. of milk | ~\

fat and solids not fat j y watered

sp. gr. of solids normal )

sp. gr. of milk and of solids ") , . , *)

solids not fat JJUgn C skimmed

fat and solids low j

sp. gr. of milk normal ") watered

sp. gr. of solids, normal or high V and

fat and solids not fat low ) skimmed

106 Testing Milk and Its Products.

The extent of the adulteration is determined as given
below.

124. Calculation of extent of adulteration.1 In the fol-
lowing formulas, per cents, found in the control-samples,
if such are at hand, are always substituted for the legal
standards.

a. Skimming. — 1. If a sample of milk has been skim-
med, the following formula will give the number of
pounds of fat abstracted from 100 Ibs. of milk :

Fat abstracted = (x)=legal standard for fat — f, . (I)
f being the per cent, of fat in the suspected sample.

2. The following formula will give the per cent, of fat
abstracted, calculated on the total quantity of fat origi-
nally found in the milk:

x = 10o fXl°° (II)

legal standard for fat

b. Watering. — 1. If a sample is watered, the calcula-
tions are most conveniently based on the percentage of
solids not fat in the milk:

Per cent, of foreign (extraneous) water in adulterated

milk - 100 S X 100 an,

legal standard for solids not fat

S being the per cent, of solids not fat in the suspected
sample.

Example: A sample of milk contains 7.5 per cent, solids not
fat; if the legal standard for solids not fat is 9 per cent.,

100— — — =16.7, shows the per cent, of extraneous water

y

in the milk.

2. Watering of milk may also be expressed in per cent,
of water added to the original milk, by formula IV:

1 Woll, Handbook for Farmers and Dairymen, New York, 1897, pp. 207-8.

The Lactometer and its Application. 107

Per cent, water added to original milk
_ N _100 X leg. stand, for sol. not fat rr\n

= (x) = a • (.-*-*/

100 X 9

In the example given above, — — 100 = 20 per

i «Q

cent, of water was added to the original milk.

c. Watering and skimming. — If a sample has been both
watered and skimmed, the extent of watering is ascer-
tained by means of formula (III) or (IV), and the fat
abstracted found according to the following formula:

Per cent, fat abstracted =

leg. stand . for sol . not fat „ , ,r .
(x)=leg. stand, for fat -Xf . (V)

b

Example: A sample of milk contains 2.4 per cent, of fat
and 8.1 per cent, solids not fat; then

Extraneous water in milk=100-?^ —=10 per cent.

y

Q y 2 4
Fat abstracted = 3 - * =.33 per cent.

O.I

100 ft>s. of the milk contained 10 Ibs. of extraneous water and
.33 Ibs. of fat had been skimmed from it.

For methods of detection of other adulterations and of
preservatives in dairy products, see Chapter X, 281
et seq.

CHAPTEE VII.
TESTING THE ACIDITY OF fllLK AND CREAfl.

125. Cause of acidity in milk. Even directly after milk
is drawn from the udder it will be found to have an acid
reaction, when phenol phtalein is used as an indicator.1
The acidity in fresh milk is not due to the presence of
free organic acids in the milk, like lactic or citric acid,
but to acid phosphates, and possibly also in part to free
carbonic acid gas in the milk or to the acid reaction of
casein. Even in case of so called sweet milk, nearly
fresh from the cow, a certain amount of acidity, viz.,
on the average about .07 per cent., is therefore found.
When the milk is received at the factory it will rarely
test less than .10 per cent, of acid, calculated as lactic
acid; some patrons bring milk day after day that does
not test over .15 per cent, of acid; that of others tests
from .20 to .25 per cent., and some lots, although very
rarely, will test as high as .3 of one per cent, of acid.
It has been found that milk will not usually smell or
taste sour or " turned," until it contains .30 to .35 per
cent, of acid.

126. The acidity in excess of that found normally in
milk as drawn from the udder, is due to other causes
than those described. Bacteriological examinations of
milk from different sources and of the same milk at dif-
ferent times have shown that there is a direct relation

i Freshly drawn milk shows an amphoteric reaction to litmus, i. e., it
colors blue litmus paper red, and red litmus paper faintly blue.

Testing the Acidity of Milk and Cream. 109

between the bacteria found in normal milk, and its acid-
ity; the larger the number of bacteria per unit of milk,
the higher the acidity of the milk. The increase in the
acidity of milk on standing is caused by the breaking-
down of milk sugar into lactic acid through the influence
of acid-forming bacteria. Since the bacteria get into
the milk through lack of cleanliness during the milking,
or careless handling of the milk after the milking, this
being kept under conditions that favor the multiplica-
tion of the bacteria contained therein, it follows that an
acidity test of new milk will give a good clue to the care
bestowed in handling the milk. Such a test will show
which patrons take good care of their milk and which
do not wash their cans clean or their hands and the
udders of the cows before milking, and have dirty ways
generally in milking and caring for the milk. The acidity
test is always higher in summer ttian in winter, and is
generally high in case of milk kept for more than a day
(Monday milk), or delivered after a warm, sultry day
or night. The bacteria have had a chance to multiply
enormously in such milk, even if it be kept cooled down
to 40°-50°F., and as a result considerable quantities of
lactic acid have been formed. The determination of the
acidity of fresh milk is explained in detail below (143).
127. Methods of testing acidity. Methods of measuring
the acidity or alkalinity of liquids by means of certain
chemicals giving characteristic color reactions in the
presence of acid or alkaline solutions (so-called volumetric
methods of analysis) have been in use for many years in
chemical laboratories. They were applied to milk as
early as 1872 by Soxhlet,1 and the method worked out

i Jour. f. prakt. Chemie, 1872, p. 6, 19.

110 Testing Milk and Its Products.

by Soxhlet and Henkel has since been in general use by
European chemists. They measured out 50 cc. of milk
ta which was added 2 cc. of a 2 percent, alcoholic solu-
tion of phenolphtalein, and this was titrated with a one-
fourth normal soda solution1 (see below). In this country,
Dr. A. G. Manns in 1890 published the results of work
done in the line of testing the acidity of milk and
cream,2 and the method of procedure and apparatus
proposed by him has become known under the name of
Manns' test, and has been advertised as such by dealers
in dairy supplies.

128. Manns' test. The acid in milk or cream is meas-
ured by using an alkali solution of a certain strength,
with an indicator which shows by a change of color in
the milk when all its acid has been neutralized. Any
of the alkalies, soda, potash, ammonia, lime or barium
can be used for making the standard solution, but it
requires the skill and apparatus of a chemist to prepare it
of the proper strength. A one-tenth normal solution3 of
caustic soda is the alkali solution used most frequently
in determining the acidity of milk, and is the solution
labeled Neutralizer of the Manns' test.

1 Fleischmann, Lehrb. d. Milch wirtschaft, p. 126.

2 Illinois experiment station, bulletin No. 9.

3 Normal solutions, as a general rule, are prepared so that one liter
shall contain the hydrogen equivalent of the active reagent weighed in
grams (Button). Caustic soda (Na. OH.) is made up of an atom each of
sodium (Na), oxygen (O), and hydrogen (H); its molecular weight is
therefore

23 + 16 + 1 = 40

Na O H

A normal soda solution then is made by dissolving 40 grams of soda in
water, making up the volume to 1000 cc.; a one-tenth normal solution will
contain one-tenth of this amount of soda, or 4 grams dissolved in one liter.
One cubic centimeter of the latter solution will contain .004 grams of soda,
and will neutralize .009 grams of lactic acid. The formula for lactic acid is
C3 H6 O3 (see page>16), and its molecular weight therefore 3x12+6x1+3x16
=90. A one-tenth normal solution of lactic acid contains 9 grams per liter,
and .009 grams per cubic centimeter.

Testing the Acidity of Milk and Cream. Ill

The indicator used is a solution of phenolplitalein, a yel-
lowish light powder; its compounds with alkalies are
red, in weak alkaline solutions pink colored, while its
acid compounds are colorless. The phenolphtalein solu-
tion used is prepared by dissolving 10 grams in 300 cc.
of 90 per cent, alcohol (Mohr).

129. In testing the acidity of either milk or cream it
is necessary to measure out with exactness the quantity
of liquid to be tested ; Manns recommended using a 50 cc.
pipette. This amount of milk or cream is measured into
a clean tin, porcelain or glass cup, a few drops of the
phenolphtalein solution are added, and the Neutralizer
(or alkali solution) is cautiously dropped in from a bur-
ette, the point at which the solution stands before any is
drawn out being noted. By constant stirring during this
operation it will be noticed that the pink color formed
by the addition of even a drop of alkali solution will at
first entirely disappear, but as more and more of the acid
in the sample becomes neutralized, the color will disap-
pear more slowly, until finally a point is reached when
the pink color remains permanent for a time. No more
alkali should be added after the first appearance of a
uniform pink color in the sample. This color will fade
and gradually disappear again on standing, owing to the
effect of the carbonic acid of the air, to which phenol-
phtalein is very sensitive. The amount of the alkali solu-
tion used for the test is then obtained from the reading
on the scale of the burette. The per cent, of acid in the
sample is calculated by multiplying the number of cc. of
alkali solution used, by .009 and dividing the product
by the number of cc. of the sample tested, the quotient
being multiplied by 100.

112 Testing Milk and Its Products.

c. c. alkali X.009

Per cent, acidity — — j x 100

c. c. sample tested

If 50 cc. of cream required 32 cc. of alkali solution to
produce a permanent pink color, the per cent, of acid in

32 X 009

the cream would be — ^ — X 100 =.58 per cent. Apart
50

of this calculation may be saved by using a factor for
multiplying the number of cc. of alkali added in each
test. This factor is obtained by dividing .009 (the num-
ber of grams of lactic acid neutralized by one cc. of alkali
solution) by the number of cc. of sample tested, and mul-
tiplying the quotient by 100. If a 50 cc. pipette is used
for measuring the sample to be tested, the factor will be
(.009-^-50)XlOO = .018; if a 25 cc. pipette is used, the
factor will be (.009-5-25) X 100^.036; and if a 20 cc.
pipette is used, (.009^-20) Xl00 = . 045 will be the factor
to be applied in calculating the per cent, of acidity, the
number of cc. of alkali used being in all cases multiplied
by the particular factor corresponding to the volume of
the sample tested.

130. If a Babcock milk-test pipette is taken for meas-
uring the milk or cream to be tested for acidity, the
factor will be (.009-^-17.6) X 100 =.051. This is so
nearly .05 that sufficiently accurate results may be
obtained by simply dividing the number of cc. used by
two; the result will be the per cent, of acid in the sample
tested, e. g., if 17.6 cc. of cream required 12 cc. of one-
tenth normal alkali to give the pink color, then the per
cent, of acid is 12 -=-2 = .6 per cent.

131. Manns' testing outfit. The apparatus (see Fig.
40) and chemicals needed for testing the acidity of milk

Testing the Acidity of Milk and Cream. 113

or cream by the so-called Manns' test include
one gallon one-tenth normal alkali solution;
four ounces of an alcoholic solution of phe-
nolphtalein, one 50 cc. glass burette with
stop-cock, one burette stand, and a pipette
for measuring the sample. This outfit will
make about 100 tests and is sold for $5.00.

132. The Alkaline tablet test. Solid alka-
line tablets were proposed by Farrington in
1894, as a substitute for the liquid used in
Manns' test.2 It is found possi-
ble to mix a solid alkali and
coloring matter, and compress
the mixture into a small tablet,

FIG. 40. Apparatus used in

which would contain an exact Manns' test.

amount of alkali. The advantage of the tablets lies in
the fact that they will keep far better than a standard
alkali solution, and they can be easily and safely sent
by mail; they also require less apparatus and are con-
siderably cheaper than standard alkali solutions; 1,000
of these tablets, costing $2.00, will make about 400 tests.3
Similar alkaline tablets were placed on the market in
Europe at about the same time, viz., Stokes' Acidity Pellets
in 1893, andEichler'stfaim^itoi (acid-pills) in 1895. *

Two methods of using the tablets have been proposed,
one, for the titration (determination of acidity) of ripen.

1 Devarda's acidimeter (Milchzeitung, 1896, p. 785) is built on the same
principle as Manns' test; one-tenth soda solution is added to 100 cc. of milk
in a glass-stoppered graduated flask, 2 cc. of a 4 per cent, phenol phtalein
solution being used as an indicator. The graduations on the neck of the
flask give the "degrees acidity" directly.

2 Illinois experiment station, bulletin No. 32.

3 The tablets are sold by dealers in dairy supplies.

4 Milchzeitung, 1895, pp. 513-16.

8

114

Testing Milk and Its Products.

ing cream in the manufacture of sour-cream butter; and
the other, for determining the approximate acidity of
different lots of apparently sweet milk or cream.

133. Determination of acidity in sour cream. The

method is equally applicable for the determination of the
acidity of sour cream, sour milk and butter- milk, but is
most frequently employed in testing the acidity of ripen-
ing cream, to examine whether or not the ripening pro-

Pi

I i ndet»

FIG. 41. Apparatus used for determining the acidity of cream or milk.

cess has reached the proper stage for churning the cream.
The apparatus used (see Fig. 41) is as follows:

1 Babcock 17.6 cc. pipette.

1 white cup.

100 cc. graduated cylinders; it is well to provide two
or three of these, although only one is strictly necessary.

Testing the Acidity of Milk and Cream. 115

134. Preparation of the solution. The tablet solution
formerly used was prepared by dissolving five tablets in
50 cc. of water; with 20 cc. of cream each cubic centi-
meter of this solution represents .017 per cent, of acid
(lactic acid) in the sample tested. The amount of acid
in a given sample is then obtained by multiplying the
number of cubic centimeters of the tablet solution used
by .017.

135. According to a suggestion made by Mr. C. L.
Fitch,1 the strength of the solution has been changed in
such a manner that the percentages of acidity are indi-
cated directly by the number of cubic centimeter of tab-
let solution used in each test. The solution may be
made up in two ways, viz., by use of a 20 cc. or a 17.6
cc. pipette.

a. Use of 20 cc. pipette. When a 20 cc. pipette is used
for measuring the sample to be tested, the tablet solution
is prepared by dissolving one tablet for every 17 cc. of
water; for five tablets 85 cc. of water are therefore taken.
When made in this way, each cubic centimeter of solu-
tion rep resents. 01 per cent, of acid in the sample tested,
10 cc. being equal to .10 per cent, acid, 32 cc. to .32 per
cent., 65 cc. to .65 per cent., etc.

b. Use of 17.6 cc. pipette. The 17.6 cc. Babcock milk
test pipette may be used for measuring the sample for
acidity testing, and the results read directly from the
graduated cylinder, if the tablet solution is prepared by
taking one tablet for every 19.5 cc. of water; five tablets
are therefore dissolved in 97 cc. of water.

136. As cream during its ripening process under our
conditions generally has from .5 to .6 per cent, of acid

l Hoard's Dairyman, Sept. 3, 1897.

116 Testing Milk and Its Products.

before it is ready to churn, a 50 cc. cylinderful of tablet
solution of this strength will not be sufficient to make a
test of cream containing over .5 per cent of acid, although
it is enough for testing the cream up to this point during
the ripening process. The acid-testing outfit should
therefore contain a 100 cc. graduated cylinder, instead
of one of 50 cc. capacity, so that cream of any amount of
acidity up to 1 per cent, can be tested. A tablet solution
of the strength given has not only the advantage over
the solution previously recommended (5 tablets to 50 cc.
of water)1 of showing the per cent, of acidity directly,
without tables or calculations, but being weaker, the
unavoidable errors of determination are decreased by
its use.

Equally accurate results may be obtained by using
solutions made up according to method a or method 6,
explained in the preceding. The latter method (17.6 cc.
cream, 5 tablets per 97 cc. of water) has, however, the
advantage in point of economy of apparatus, since a
17.6 cc. pipette is found in creameries and dairies with
the Babcock test outfit and is therefore most likely
already available for use in testing the acidity of cream.
This method is therefore considered preferable and
referred to as

137. The standard solution. The preparation of this
solution is as follows: Five tablets are placed in the
100 cc. cylinder which is filled to the 97 cc. mark with
clean soft water2. The cylinder is tightly corked, shaken

i_ Illinois experiment station, bulletin No. 32; Wisconsin experiment
station, bulletin No. 52.

2 Condensed steam or rain water should be used, and not hard water
or alkali water, since the impurities in these affect the strength of the
tablet solution.

Testing the Acidity of Milk and Cream. 117

and laid on its side, as the tablets will dissolve more
quickly when the cylinder is placed in this position than
when left upright with the tablets at the bottom. Several
cylinders containing the tablet solution may be prepared
at a time; as soon as one is emptied, tablets and water
are again added, and the cylinder is corked and placed
in a horizontal position. In this way fresh solutions
ready for testing are always at hand. The cylinder is
kept tightly corked while the tablets are dissolving, so
that none of the liquid is lost by the shaking. It is well
to put the tablets in the cylinder with water at night;
the solution will then be ready for use in the morning.
Excepting a flocculent residue of inert matter, " set-
tlings," which will not dissolve, the tablets must all dis-
appear in the solution before this is used. The strength
of the tablet solution does not change perceptibly by
standing for twenty-four hours; but a change takes place
in solutions older than this. The solid tablets will not
change if kept dry any more than dry salt changes by age.
The only precaution necessary is to use a fresh solution
when acidity tests are made.

138. Accuracy of the tablets. The tablets have been
repeatedly tested by competent persons and found to be
accurate and very uniform in composition. Tests made
with the tablets according to the directions here given
can be relied on as correct. The alkali solution is very
sensitive however and should not be measured in a cylin-
der which has been previously used for measuring sulfu-
ric acid as the smallest drop or film of acid from a dish
or from the operator's fingers will change the standard
strength of the tablet solution. The tablets must be com-

118 Testing Milk and Its Products.

pletely dissolved before the standard solution is used
and the solution must be made with clean water.

139. Making the test. The cream to be tested is thor-
oughly mixed, and 17.6 cc. is measured into the cup.
The pipette is rinsed once with water, and the rinsings
added to the cream in the cup. A few cc. of the tablet
solution prepared as given above are now poured from
the cylinder into the cream and mixed thoroughly with
it by giving the cup a gentle rotary motion. The tablet
solution is added in small quantities until a permanent
pink color appears in the sample. The number of cc. of
tablet solution which have been used to color the cream
is now read off on the scale of the cylinder.

In comparing the results of one test with another, the
same shade of color should always be adopted. The
most delicate point is the first change from pure white or
light yellow to a uniform pink color which the sample
shows when the acid contained therein has just been neu-
tralized. This shade of color is easily recognized with a
little practice. The pink color is not permanent unless
a large excess of the alkaline solution has been added, on
account of the influence of the carbonic acid of the air
(129), and the operator should not therefore be led to
believe by the reappearance of the white color after a
time, that the point of neutralization was not already
reached when the first uniform shade of pink was
observed.

140. Acidity of cream. 17.6 cc. of sweet cream is gen-
erally neutralized by 15-20 cc. of this tablet solution,
representing from .15 to .20 per cent, of acid. A mildly
sour cream is colored by 35 cc. tablet solution, and a sour

Testing the Acidity of Milk and Cream. 119

cream ready for churning by about 50 60 cc. tablet solu-
tion. As the cream ripens, its acidity increases. The
rate of ripening depends largely on the temperature at
which the cream is kept. Cream containing .5 to .6 per
cent, of acid will make such butter as our American
market demands at the present time. Cream showing
an acid test of .55 per cent, may not be too sour, but .65
per cent, of acid is very near, if not on the danger line,
since such cream is likely to make strong flavored, almost
rancid butter. Each lot of cream should be tested as
soon as it is ready for ripening, and the result of the test
will show whether the cream should be warmed or cooled
in order to have it ready for churning at the time desired.
Later tests will show the rate at which the ripening is
progressing, and the time when the cream has reached
the proper acidity for churning.

141. The influence of the richness of cream on the acid
test has been studied by Professor Spillman, * and others.2
Since the acidity develops in the cream serum, it follows
that an acidity of, say .5 per cent, in a 40 per cent.-
cream represents a larger acidity than in 20 per cent. -
cream, e. g. In the former case we have .5 grams of
acid in 60 grams of serum ( =.83 per cent, of the serum);
in the latter case .5 grams acid is found in 80 grains
serum (=.63 per cent, of the serum). Therefore, rich
cream need not be ripened to as high a degree of acidity
as thin cream. A table is given in the bulletin referred
to, showing the relation between the richness and the
acidity of cream.

1 Washington experiment station, bulletin No. 32.

2 Chicago Dairy Produce, April 21, 1900, p. 30, Bull. 52, Iowa Expt. Sta.

120

Testing Milk and Its Products.

142. Sgillman's cylinder. The graduated cylinder shown
in Fig. 42 was devised by Professor Spillman for use in
testing the acidity of milk and cream with
Farrington's alkaline tablets. The follow-
ing directions are given for making tests
with this piece of apparatus:1

"All that is needed in addition to the acid test
graduate shown in the accompanying illustra-
tion, is a common prescription bottle of six or
eight ounce capacity, and a package of Farring-
ton's alkaline tablets. Fill the bottle with water
and add one tablet for each ounce of water in
the bottle. Shake the bottle frequently to aid
in dissolving the tablets.

"Making the test. In making the test, the
.. acid-test graduate is filled to the zero mark with
I ,FIG. 42. spill- the milk or cream to be tested. The tablet solu-

u^ed'8 in^dSer- tion is the11 added> a Uttle at a tim6' and the
Dining the acid- graduate shaken after each addition, in order to

ity of cream or thoroughly mix the milk and the tablet solution.
milk- In shaking the graduate, give it a rotary motion

to prevent spilling any of the liquid. Continue adding the
tablet solution until a permanent pink color can be detected in
the milk. The level of the liquid in the graduate, measured by
the scale on the graduate, will then be the per cent, of the acid-
ity of the milk. It is best to stand the graduate on a piece of
white paper, so that the first pink coloration of the milk may
be easily detected."

143. Rapid estimation of the acidity of apparently sweet
milk or cream, a, Milk. The alkaline tablet method offers
a ready means of estimating the acidity of milk or cream
that is still apparently sweet. The selection of the best
kinds of milk is especially important in pasteurizing milk
or cream. Investigations have shown that milk which
gives the highest acid test contains, as a rule, a larger

i Washington experiment station, bulletin No. 24.

Testing the Acidity of Milk and Cream. 121

number of bacteria and spores not destroyed by pasteur-
ization than does milk giving a low acid test (126); the
acidity test may therefore be used to advantage for the
purpose of selecting milk best adapted for pasteurization,
as well as such as is to be retailed or used in the manu-
facture of high-grade butter and cheese.

& Ounce Bottle. "Measure

FIG. 43. Apparatus used for rapid estimation of the acidity of appar-
ently sweet milk or cream.

In distinguishing milk fit for pasteurization purposes
from that which is doubtful, an arbitrary standard of
two-tenths of one per cent, of acid may be taken as the
upper limit for milk of the former kind. The appara-
tus used in making this test is shown in the accom-
panying illustration (Fig. 43), and consists of a white
teacup; a four-, six-, or eight-ounce bottle, and a No. 10
brass cartridge shell, or a similar measure. A solution
of the tablets in water is first prepared, one tablet being

122 Testing Milk and Its Products.

always added for each ounce of water: four tablets in a
four-ounce bottle; six, in a six-ounce bottle, etc., the
amount of tablet solution prepared depending on the
number of tests to be made at a time. The bottle is
filled up to its neck with clean soft water, and the solu-
tion prepared in the manner previously given (137).

144. Operating the test. As each lot of milk is brought
to the creamery in the morning and poured into the
weigh can, it is weighed and the cartridge- shell dipper
filled with the milk is emptied into the white cup. The
same or another No. 10 shell is now filled twice with the
tablet solution and emptied into the milk in the cup.
Instead of dipping twice with one measure or a No. 10
shell, a tin measure can be made holding as much as two
No. 10 shells, or the tablet solution may be made of
double strength, that is, two tablets to each ounce of
water and the same sized measure for both the milk and
the tablet solution used. The liquids are then mixed
in the cup by giving this a quick, rotary motion, and
the color of the mixture noticed. If the milk remains
white it contains more than two-tenths of one per cent,
of acid and should not be used for pasteurization. If it
is colored after having been thoroughly mixed with two
measures of tablet solution, it contains less than this
amount of acid and may, as far as acidity goes, be
safely used, for pasteurization or for any other purpose
which requires thoroughly sweet milk. The shade of
color obtained will vary with different lots of milk; the
sweetest milk will be most highly colored, but a milk
retaining even a faint pink color with two measures of
tablet solution or one measure of the double strength

Testing the Acidity of Milk and Cream. 123

solution to one measure of m,ilk contains less than .2 per
cent, of acid.

By proceeding in the manner described, the man re-
ceiving and inspecting the milk at the factory weigh- can
is able to test the acidity of the milk delivered nearly as
quickly as he can weigh it; and according to the results
of the test he can send the milk to the general delivery
vat or to the pasteurization vat, as the weighing-can may
be provided with two conductor spouts.

145. Size of measure necessary. It is not necessary to
use a No. 10 shell for a measure in working the preced-
ing method; one of any convenient size that can be filled
accurately and quickly, will answer the purpose equally
well, if a measure of the same size is used for both the
sample and the tablet solution. Each measureful of tab-
let solution made up as directed, will in this case repre-
sent one-tenth per cent, of acid in the sample tested.

146. b, Cream. Cream can be tested in the way already
described for testing the acidity of fresh milk, by adding
to one measureful of cream in the cup as many measures
of tablet solution as are necessary to change the color of
the cream when the two liquids are thoroughly mixed.
If one measure of tablet solution colors one measure of
cream, this contains less than .1 per cent, acid; if five
measures of tablet solution are required, the cream con-
tains about .5 per cent, acid, etc. By proceeding in the
manner described, the operator can estimate the acidity
to within .05 per cent, of acid, if half measures of tablet
solution are added. The results thus obtained are suffi-
ciently delicate for all practical purposes.

124 Testing Milk and Its Products.

147. Detecting boracic-acid preservatives in milk. The applica-
tion of the alkaline tablet test for detecting boracic acid in milk
was first discussed in bulletin No. 52 of Wisconsin experiment
station. The acidity of the milk is increased by the addition
of boracic acid, but neither the odor nor the taste of the milk is
affected thereby. By adding to sweet milk the amount of boracic
acid which will keep it sweet for 36 hours, its acidity may be
increased to .35 per cent., in a sample of milk which previously
tested perhaps only .15 per cent. acid.

As before stated, unadulterated milk will usually smell or
taste sour or "turned," when it contains .30-.35 per cent, acid
(118); milk testing as high as this limit, which neither smells
nor tastes sour in any way, is therefore in all probability adul-
terated with some preparation containing boracic acid or a
similar compound.

148. "Alkaline tabs." These are not alkaline tablets, but a sub-
stitute which was put on the market by a New York firm.
The outfit furnished consisted of four packages of paper discs
made of filter paper, each of about the size of an old-style copper
cent; two packages of square paper; one glass of about 10 cc.
capacity, and one small glass bottle. An investigation of the
reliability of these "Tabs" soon disclosed the fact that they
were entirely inaccurate, and that no dependence could there-
fore be put on the results obtained by their use.

CHAPTER VIII.
TESTING THE PURITY OF MILK.

149. The Wisconsin curd test. Cheese makers are often
troubled with so-called floating or gassy curds which
produce cheese defective in flavor and texture. These
faults are usually caused by some particular lot of milk
containing impurities that cannot be detected by ordi-
nary means of inspection. The Wisconsin curd test is
used to detect the source of these defects and thus enable
the cheese maker to exclude the milk from the particular
farm or cow to which the trouble is traced. This test is
similar in principle to tests that have for many years
past been in use in cheese-making districts in Europe,
notably in Switzerland,1 but was worked out independ-
ently at the Wisconsin Dairy School in 1895 and has
become generally known as the " Wisconsin Curd Test"
from the description of it in the report of the Wisconsin
experiment station for 1895.2

The apparatus used for the test was greatly improved
in 1898, and a description of the improved test is given
in bulletin No. 67 and the annual report of this station
for 1898, 3 from which source the accompanying illustra-
tions are taken (see Figs. 45 and 46).

150. Method of making the test. Pint glass jars, thor-
oughly cleaned and sterilized with live steam, are pro-

1 Herz, Unters. d. Kuhmilch, Berlin, 1889, p. 87; Siats, Unters. landw.
wicht. Stoffe, 1897, pp. 129-131.

2 Twelfth report, p. 148.

3 Fifteenth report, pp. 47-53.

126 Testing Milk and Its Products.

vided; they are plainly numbered or tagged, one jar
being provided for each lot of milk to be tested. The
jars are filled about two-thirds full with the milk from
the various sources; it is not necessary to take any exact
quantity; they are then placed in a water tank, the water
of which is heated until the milk in the jars has a tem-

FIG. 44. Students operating the Wisconsin curd test

perature of 98° F. The thermometer used must not be
transferred from one sample to another, unless special
precautions are taken, for fear of contaminating the pure
lots of milk by impure ones.

When the milk has reached a temperature of 98°, add
to each sample ten drops of rennet extract, and mix by
giving the jar a rotary motion. The milk is thus cur-

Testing the Purity of Milk.

127

died, and the curd allowed to stand for about twenty
minutes until it is firm. It is then cut fine with a case
knife, and after settling, the whey is poured off. The
best tests are made when the separation of the whey is
most complete. By allowing the samples to stand for a

FIG 45. The Wisconsin curd test. 1, Test jars draining; 2, whey outlet;
3, test jars in water tank; 4, test jars in parts; 5, stop cock for water; 6,
stand to support cover.

FIG, 46. Cross-section of the Wisconsin curd test. T J-TJ", testing jars
showing different stages of test; WL,, water line; M, milk; F, frame; WS,
stand to support cover; AI, drain holes; TVO, water outlet; DP, drain pail.

128 Testing Milk and Its Products.

short time, more whey can be poured off, and the curd
thereby rendered firmer. The water around the jars is
kept at a temperature of 98°, the vat is covered, and the
curds allowed to ferment in the sample jars for six to
twelve hours.

During this time the impurities in any particular sam-
ple will cause gases to be developed in the curds so that
by examining these, by smelling of them and cutting them
with a sharp knife, those having a bad flavor or a spongy
or in any way abnormal texture may be easily detected,
and the milk from which it was made, thereby picked
out.

151. By proceeding in the same way with the milk
from the different cows in a herd, the mixed milk of
which produced abnormal curds, the source of contami-
nation in the herd may be located. Very often the
trouble will be found to come from the cows' drinking
foul stagnant water or from fermenting matter in the
stable. In the former case the pond or marsh must be
fenced off, or the cows kept away from it in other ways;
in the latter, a thorough cleaning and disinfection of the
premises are required. If the milk of a single cow is
the source of contamination, it must be kept by itself,
until the milk is again normal; under such conditions the
milk from the healthy cows may of course safely be sent
to the factory.

152. The fermentation test. The Gerber fermentation test (see
fig. 47) furnishes a convenient method for examining the purity
of different lots of milk. The test consists of a tin tank which
can be heated by means of a small lamp, and into which a rack

Testing the Parity of Milk. 129

fits, holding a certain number of cylindrical glass tubes; these
are all numbered and provided with a mark and a tin cover.
In making the test, the tubes are filled to the mark with milk,
the number of each tube being recorded in a note-book, oppo-
site the name of the particular patron whose milk was placed
therein. The tubes in the rack are put in the tank, which is
two-thirds full of water; the temperature of the water is kept
at 104-106° F. for six hours, when the rack is taken out, the
tubes gently shaken, and the appearance of the milk, its odor,
taste, etc., carefully noted in each case.

The tubes are then
again heated in the tank
at the same temperature
as before, for another six
hours, when observa-
tions of the appearance
of the milk in each tube
are once more taken.
The tainted milk may
then easily be discov-
ered by the abnormal FIG. 47. The Gerber fermentation test,
coagulation of the sample. According to Gerber,1 good and
properly handled milk should not coagulate in less than twelve
hours, when kept under the conditions described, nor show
anything abnormal when coagulated. Milk from sick cows
and from cows in heat, or with diseased udders, will always
coagulate in less than twelve hours. If the milk does not curdle
inside of a day or two, it should be tested for preservatives
(290).

153. The Monrad Rennet test is used by cheese makers
for determining the ripeness of milk. Fig. 48 shows the
apparatus used in the test. 5 cc. of rennet extract is
measured by means of a pipette into a 50 cc. flask 5 the

i Die praktische Milchpriifung, p. 85.
9

130

Testing Milk and Its Products.

pipette is rinsed with
water and the flask filled
to the mark with water.
160 cc. of milk is now
measured into the tin basin
from the cylinder and
slowly heated to exactly
86° F. 5 cc. of the dilu-
ted rennet solution is then
quickly added to the warm
milk and the time required
for coagulation noted.1
Milk sufficiently ripe for
cheddar cheese making
will coagulate i n 30-60
seconds, according to the
strength of the rennet ex-
tract used.

FIG. 48. The Monrad rennet test.

154. The Marshall Rennet test is used for the same
purpose as the Monrad test. The time required for
coagulating the milk is shown directly by a scale given
on the apparatus.

i Decker, Cheese Making, 1900, p. 36.

CHAPTEE IX.
TESTING MILK ON THE FARM.

155. Variations in milk of single cows. The variations
in the tests of milk of single cows from milking to milk-
ing or from day to day, are greater than many cow-
owners suspect. There seems to be no uniformity in this
variation, except that the quality of the milk produced
generally improves with the progress of the period of
lactation; even this may not be noticeable, however,
except when the averages of a number of tests made at
different stages during the lactation period are compared
with each other. When a cow gives her maximum
quantity of milk, shortly after calving, the quality of her
milk is generally poorer (by one per cent, of fat, or less)
than when she is drying off. Strippers' milk is therefore
as a rule richer in fat than the milk of fresh cows.

156. By testing separately every milking of a number
of cows through their whole period of lactation, the
results obtained have seemed to warrant the following
conclusions in regard to the variations in the test of the
milk from single cows, and it is believed that these
conclusions allow of generalization.1

1. Some cows yield milk that tests about the same at
every milking, and generally give a uniform quantity of
milk from day to day.

2. Other cows give milk that varies in an unexplain-
able way from one milking to another. Neither the

i Illinois experiment station, bulletin No. 24.

132 Testing Milk and Its Products.

morning nor the evening milking is always the richer,
and even if the interval between the two milkings is
exactly the same, the quality as well as the quantity of
milk produced will vary considerably. Such cows are
mostly of a nervous, excitable temperament, and are
easily affected by changes in feed, drink, or surrounding
conditions.

3. The milk of a sick cow, or of a cow in heat, as a
rule, tests higher than when the cow is in a normal
condition; the milk yield generally decreases under such
conditions; marked exceptions to this rule have, however,
been observed.

4. Half- starved or underfed cows may give a small
yield of milk testing higher than when the cows are
properly nourished, probably on account of an accompa-
nying feverish condition of the animal. The milk is,
however, more generally of an abnormally low fat con-
tent, which may be readily increased to the normal per
cent, of fat by liberal feeding.

5. Fat is the most variable constituent of milk, while
the solids not fat vary within comparatively narrow
limits. The summary of the analyses of more than 2400
American samples of milk calculated by Cooke1 shows
that while the fat content varies from 3.07 to 6.00 per
cent., that of casein and albumen varies only from 2.92
to 4.30 per cent., or less than one and one-half per cent.,
and the milk sugar and ash content increases but little
(about .69 per cent.) within the range given.

6. A test of only one milking may give a very erro-
neous impression of the average quality of a certain

i Vermont experiment station, report f. 1890, p. 97.

Testing Milk on the Farm. 133

cow's milk. A composite sample (see 175) taken from
four or more successive milkings will more nearly repre-
sent the quality of the milk which a cow produces at the
time of sampling.

157. The variations that may occur in testing the milk
of single cows, are illustrated by the following figures
obtained in an experiment made at the Illinois experi-
ment station, 1 in which the milk of each of six cows was
weighed and analyzed daily during the whole period of
lactation. Among the cows were pure-bred Jerseys,
Shorthorns and Holsteins, the cows being from three to
eight years of age and varying in weight from 850 to
1350 Ibs. During a period of two months of the year,
the cows were fed a heavy grain ration consisting of 12
Ibs. of corn and cob meal, six Ibs. of wheat bran, and six
Ibs of linseed meal, per day per head. This system of
feeding was tried for the purpose of increasing, if possi-
ble, the richness of the milk. The influence of this
heavy grain feed, as well as that of the first pasture
grass feed, on the quality and the quantity of the milk
produced is shown in the following table, which gives
the complete average data for one of the cows (No. 3).
The records of the other cows are given in the publica-
tion referred to; they were similar to the one here given
in so far as variations in quality are concerned.

i Bulletin No. 24.

134

Testing Milk and Its Products.

Average results obtained in weighing and testing a cow's milk
daily during one period of lactation.

MONTH.

3

to

Daily milk
yield.

Tests of one
day's milk.

Yield of fat
per day.

p

fi

II

5

I5

1

-i -,

i|

|l

II

5

1e •

December ....
January
February
March
April

920
927
1035
1017
1054
1079
1105
1180
1130

12.1
16.0
16.1
14.3
13.8
14.5
12.1
9.3
6.4

16.0
17.7
17.7
16.0
16 5
17.2
14.0
12.2
9.3

10.0
14.0
13.5
12.5
11.5
10.0
9.2
6.0
3.5

3.8
3.7
3.6
3.8
4.0
3.8
3.9
4.2
4.7

4.9
4.6
5.8
4.7
5.8
4.6
4.6
6.2
7.9

3.0
2.7
3.2
3.4
3.0
3.4
3.2
2.8
2.9

.46
.59
.58
.54
.55
.55
.47
.39
.30

.60
.76
.84
.61
.72
.70
.57
.60
.50

.34
.44
.51
.50
.46
.44
.35
. .27
.16

May

June

July

August

158. The average test of this cow's milk for her whole
period of lactation was 3.8 per cent, of fat (i. e., the total
quantity of fat produced -f- total milk yield X 100); twice
during this time the milk of the cow tested as high as
5.8 per cent., and once as low as 2.7 per cent., while tests
of 3.0 and 4.6 per cent, were obtained a number of times.
The average weight of milk produced per day by the
cow was 14 Ibs. ; this multiplied by her average test, 3.8,
shows that she produced on the average .53 Ibs., or about
one-half of a pound, of butter fat per day during her lac-
tation period. If, however, her butter-producing capac-
ity had been judged by the test of her milk for one day
only, this test might have been made either on the day
when her milk tested 5.8 per cent., or when it was as low
as 2. 7 per cent. Both of these tests were made in mid-
winter when the cow gave about 16 Ibs. of milk a day.
Multiplying this quantity by .058 gives .93 Ibs. of fat, and
by .027 gives .43 Ibs. of fat. Either result might show

Testing Milk on the Farm. 135

the butter fat produced by the cow on certain days, but
5 neither gives a correct record of her actual average daily
; performance for this lactation period.
I A sufficient number and variety of tests of the milk of

many cows have been made to prove that there is no
; definite regularity in the daily variations in the richness
• of the milk of single cows. The only change in the
f quality of milk common to all cows is, as stated, the nat-
[ ural increase in fat content as the cows are drying off,
f and even in this case the improvement in the quality of
; the milk sometimes does not occur until the milk yield
\ has dwindled down very materially.

159. Causes of variations in fat content. The quality
of a cow's milk is as a rule decidedly influenced by the
following conditions:

Length of interval between milkings.

Change of feed.

Change of milkers.

Eapidity of milking.

Eough treatment.

Exposure to rain or bad weather.

Unusual excitement or sickness.

160. Disturbances like those enumerated frequently
increase the richness of the milk for one, and sometimes
for several milkings, but a decrease in quality follows
during the reaction or the gradual return to normal con-
ditions, and taken as a whole there is a considerable
falling off in the total production of milk and butter fat
by the cow, on account of the nervous excitement which
she has gone through. Aside from changes due to well-
definable causes like those given ab«ve, the quality of

i36> testing Milkjind Its Products.

some cows' milk will often change very considerably
without any apparent cause. The dairyman who is in
the habit of making tests of the milk of his individual
cows at regular intervals will have abundant material
for study in the results obtained, and he will soon be
able to tell from the tests made, if these are continued
for several days, whether or not the cows are in a normal
healthy condition or have been subjected to excitement
or abuse in any way.

161. Number of tests required during a period of lacta-
tion in testing cows. The daily records of the six cows
referred to on page 133 give data for comparing their
total production of milk and butter fat during one period
of lactation, as found from the daily weights and tests
of their milk, with the total amount calculated from
weights and tests made at intervals of 7, 10, 15 or 30
days. The averages of all results obtained with each of
the six cows show that weighing and testing the milk of
a cow every seventh day gave 98 per cent, of the total
milk and butter fat, which according to her daily record
was the total product. Tests made once in two weeks
gave 97.6 per cent, of the total milk, and 98.5 per cent,
of the total butter fat, and tests made once a month, or
only ten times during the period of lactation, gave 96.4
per cent, of the total milk, and 97 per cent, of the total
production of butter fat.

162. The record of one of the cows will show how
these calculations are made: It was found from the
daily weights and tests that cow No. 1, in one lactation
period of 307 days, gave 5,044 Ibs. of milk which con-
tained 254 Ibs. of butter fat. Selecting every thirtieth

Testing Milk on the Farm.

137

day of her record as testing day, the total production of
milk and fat is shown to be as follows:

Production of milk and butter fat per day.

Testing day.

Weight of milk.

Test of milk.

Yield of butter fat.

Nov 4

Ibs.
20.5

per cent.
4.7

Ibs.
.96

Dec 4

18.7

4.6

.86

Jan 3

17.7

4.9

.86 %

Feb 2

20.0

4.5

.90

Mar 3

18.2

4.7

.86

April 2

19.5

4.4

.81

May 2

17.7

4.8

.85

June 1

13.1

5.5

.72

July 1

12.2

6.2

.76

July 31

3.2

7.2

.23

Total

160.8 Ibs.

7.81 Ibs.

Average per day.

16.08 Ibs.

4.85

.78 Ibs.

The average daily production of the cow, according to
the figures given in the preceding table, was nearly
16 Ibs. of milk, containing .78 Ibs. of butter fat. Multi-
plying these figures by 307, the number of days during
which the cow was milked, gives 4,903 Ibs. of milk and
240 Ibs. of fat. This is 141 Ibs. of milk and 14 Ibs. of fat
less than the total weights of milk and butter fat, as
found by the daily weights and tests, or 2.8 and 5.5 per
cent, less, for milk- and fat production, respectively.
This is, however, calculated from only ten single weights
and tests, while it required over 600 weighings and 300
tests of the milk to obtain the exact amount.

Similar calculations from the records of the other cows
gave fully as close results, showing that quite satisfac-
tory data as to the total production of milk and butter

6 -7

138 Testing Milk and Its Products.

of a cow may be obtained by making correct weighings
and tests of her full day's milk once every thirty days. t|

163. When to test a cow.1 The Vermont experiment
station for several years made a special study of the
question when a cow should be tested in order to give a
correct idea of the whole year's performance, when only
one or two tests are to be made during the lactation
period.2 The results obtained may be briefly summarized
as follows: tl

a. As to quality of milk produced. If two tests of each
cow's milk are to be made during the same lactation
period, it is recommended to take composite samples at
the intervals given below:

First sample. Second sample. -3

For spring cows, 6 weeks after calving. .6 J-7£ mos. after calving.
For summer" 8 " " "
For fall " 8-10 " " "

If only one test is to be made, approximately correct
results may be obtained by testing the milk during the
sixth month from calving, in case of spring cows; during
the third to fifth month in case of summer-calving cows,
and during the fifth to seventh month for fall-calving
cows.

In all cases composite samples of the milk for at least
four days should be taken (165). "The test of a single
sample, drawn* from a single milking or day, will not of
necessity, or indeed usually, give trustworthy results."

1 H. B. Gurler in American Dairying, p. 18, suggests that three months
after calving a cow's milk may be weighed for a week and a composite
sample tested. The average weight of butter fat produced per day is cal-
culated and this average figure multiplied by 252 or the number of days in
8.4 months. It is assumed that a cow gives milk more than 8.4 months
and the quantity produced beyond this time will bring the production
during the last 2.4 months up to the same average per month as in the
first six months.

2 Sixth report, 1882, p. 106; Ninth report, 1895, p. 176.

Testing Milk on the Farm.

139

b. As to quantity of milk produced. The milk may be
weighed for four days in the middle of the month, and
the entire month's yield obtained with considerable
accuracy (barring sickness and drying off), by multiply-
ing the sum by 7, 7J or 7f , according to the number of
days- in the different months. The weighing is most
readily done by means of a spring balance,
the hand of which is set back so that the
empty pail brings it to zero (Fig. 49. ) If
several pails are to be used, they should
first be made to weigh the same by putting
a little solder on the lighter pails. Milk
scales which weigh and automatically reg-
ister the yield of milk from twenty cows
have been placed on the market, but no
perfectly satisfactory devise of this kind
has yet been brought out, so far as is known
to the authors.

164. Sampling milk of single cows. In
sampling the milk of single cows, all the
milk obtained at the milking must be carefully mixed,
by pouring it from one vessel to another a few times, or
stirring it thoroughly by means of a dipper moved up
and down, as well as horizontally, in the pail or can in
which it is held; the sample for testing purposes is then
taken at once. A correct sample of a cow's milk cannot
be obtained by milking directly into a small bottle from
one teat, or by filling the bottle with a little milk from
each teat, or by taking some of the first, middle and last
milk drawn from the udder. Such samples cannot pos-
sibly represent the quality of the milk of one entire rnilk-

FiG.49. Milk scale.

140 Testing Milk and Its Products.

ing, since there is as much difference between the first
and the last portions of a milking, as between milk and
cream.1 Lack of care in taking a fair sample is the
cause of many surprising results obtained in testing milk
of single cows.

165. When a cow is to be tested, she should be milked
dry the last milking previous to the day when the test
is to be made. The entire quantity of milk obtained at
each milking is mixed and sampled separately. On ac-
count of the variations in the composition of the milk, a
number of tests of successive milkings must be made.
As this involves considerable labor, the plan of taking
composite samples is preferable; the method of compos-
ite sampling and testing is explained in detail under the
second subdivision of Chapter X (176); suffice it here to
say that the method followed in case of single cows' or
heid milk is to take about an ounce of the thoroughly
mixed milk of each milking; this is placed in a pint or
quart fruit jar containing a small quantity of some pre-
servative, preferably about one-half a gram (8 grains) of
powdered potassium bi-chromate. If a number of com-
posite samples of the milk of single cows are taken, each
jar should be labeled with the number or name of the
particular cow. Composite tests are generally taken for
four days or for a week. If continued for a week, the
jars will contain at the end of this time a mixture of the
milk of fourteen milkings. The composite sample is
then carefully mixed by pouring it gently a few times
from one jar to another, and is tested in the ordinary

i Woll, Handbook for Farmers and Dairymen, p 194; Agricultural
Science, 6, pp. 540-42.

Testing Milk on the Farm. 141

manner. The result of this test shows the average qual-
ity of the milk produced by the cow during the time the
milk was sampled.

166. As the amounts as well as the quality of the milk
produced by single cows vary somewhat from day to day
and from milking to milking, it is desirable in testing
single cows, especially when the test includes only a few
days, to take a proportionate part (an aliquot) of each
milking for the composite test sample. This is easily
done by means of a Scovell sampling tube, the use of
which is explained in another place (180), or by a 25 cc.
pipette divided into ^ cc. ; in using the latter apparatus as
many cubic centimeters and tenths of a cubic centimeter
of milk are conveniently taken each time for the compos-
ite sample as the weight of milk in pounds and tenths of
a pound produced by the cow.

The opinion is often expressed that a considerable
error is introduced by measuring out milk warm from
the cow for the Babcock test, since milk expands on being
warmed, and a too small quantity in this manner is
obtained. By calculation of the expansion of milk
between different temperatures it is found that 1 cc. of
milk at 17.5° C. (room temperature) will have a volume
of 1.006289 cc. at 37° C. (blood-heat), i. e., an error of
less than .03 per cent, is introduced by measuring out
milk at the latter temperature. While the temperature
has therefore practically no importance, the air incorpo-
rated in the milk during the milking process will intro-
duce an appreciable error in the testing, and samples of
milk should therefore be left for an hour or more after
milking before the test samples are taken. By this time

142

Testing Milk and Its Products.

the specific gravity of the samples can also be correctly
taken (113).

^. - 167. Size of the testing sample. Four ounces is a suffi-
c.ent quantity for a sample of milk if it is desired to
determine its per cent, of fat only; if the milk is to be
tested with a lactometer, when adulteration is suspected,
as much as a pint is needed for a sample. If this sample
of milk is put into a bottle and carried or sent away from
the farm to be tested, the bottle should be filled with
milk clear up to the cork to prevent a partial churning
of butter in the sample during transportation (30).

168. Variations in herd milk. While considerable vari-
ations in the quality of milk of single cows are often met
with, a mixture of the milk of several cows, or of a whole
herd is comparatively uniform from day to day; the indi-
vidual differences tend to balance each other so that vari-
ations, when they do occur, are less marked than in case
of milk of single cows. There are, however, at times
marked variations also in the test of herd milk on suc-
cessive days; the following figures from the dairy tests
conducted at the World's Columbian Exposition in Chi-
cago in 1893 illustrate the correctness of this statement.
The test included twenty -five Jersey and Guernsey cows
each and twenty -four Shorthorn cows.

Tests of herd milk on successive days.

DATE.

Jersey.

Guernsey.

Shorthorn.

July 16, 1893

4.8 per cent.

4.6 per cent.

3.8 per cent.

July 17, 1893
July 18, 1893

5.0 u

47 "

4.5
4.4 "

3.8
3.8 "

July 19, 1893.

4.6 "

4.6 "

3.7 "

July 20, 1893.

5.0 "

4.5 "

3.8 "

Testing Milk on the Farm. 143

On July 17, 1893, the mixed milk of the Jersey cows
tested two-tenths of one per cent, higher than on the pre-
ceding day; the Guernsey herd milk tested one- tenth of
one per cent, lower, while the Shorthorn milk did not
change in composition; comparing the tests on July 19
and 20, we find that the Jersey and Shorthorn milk tested
four- tenths and one- tenth of one per cent, higher, respect-
ively, on the latter day than on the former, and the
Guernsey milk tested one-tenth of one per cent, lower.

169. Ranges in variations of herd milk. According to
Fleischrnann,1 the composition of herd milk may on single
days vary from the average A^alues for the year expressed
in per cent, of the latter, as follows:

The specific gravity (expressed in degrees) may go above or
below the yearly average by more than 10 per cent.

The per cent, of fat may go above or below the yearly average
by more than 30 per cent.

The per cent, of total solids may go above or below the yearly
average by more than 14 per cent.

The per cent, of solids not fat may go above or below the
yearly average by more than 10 per cent.

To illustrate, if the average test of a herd during a whole
period of lactation is 4.0 per cent., the test on a single day may
exceed 4.0+T3o% X 4.0 = 5.2, or may go below 2.8 per cent, (viz.,
4.0 — T30°0 X 4.0); if the average specific gravity is 1.031 (lacto-
meter degrees, 31 2) the specific gravity of the milk on a single
day may vary between 1.0279 and 1.0341 (31 + ^ X 31 = 34.1;
31-T'o°0X31 = 27.9).

170." Influence of heavy grain-feeding on the quality of
milk. If cows are not starved or underfed, an increase
in the feeding ration will not materially change the rich-
ness of the milk produced, as has been shown by careful

1 Book of the Dairy, p. 32.

2 See page 94.

144 Testing Milk and Its Products.

feeding experiments conducted under a great variety of
conditions and in many countries. Cows that are fairly
well fed will almost invariably give more milk when
their rations are increased, but the milk will remain of
about the same quality after the first few days are passed
as before this time, provided the cows are in good health
and under normal conditions. Any change in the feed
of cows will usually bring about an immediate change in
the fat content of the milk, as a rule increasing it to some
extent, but in the course of a few days, when the cows
have become accustomed to their new feed, the fat con-
tent of the milk will again return to its normal amount.
171. The records of the cows included in the feeding
experiment at the Illinois station, to which reference has
been made on p. 133, furnish illustrations as to the effect
of heavy feeding on the quality of milk. The feed, as
well as the milk of the cows, was weighed each day of
the experiment. During the month of December each
cow was fed a daily ration consisting of 10 Ibs. of tim-
othy hay, 20 Ibs. of corn silage and 2 Ibs. of oil meal;
the table on p. 134 shows that cow No. 3 produced on
this feed an average of 12.1 Ibs. of milk, testing 3.8 per
cent, of fat. In January the grain feed was gradually
increased until the ration consisted of 12 Ibs. of timothy
hay, 8 Ibs. of corn and cob meal, 4 Ibs. of wheat bran and
4 Ibs. of oil meal. All the cows gained in milk on this
feed; cow No. 3 thus gave an average of 4 Ibs. more
milk per day in January than in December, but the aver-
age test of her milk was 3. 7 per cent., or one- tenth of one
per cent, lower than during the preceding month. The
heavy grain feeding was continued through February

Testing Milk on the Farm. 145

and March, when it reached 12 Ibs. of timothy hay, 12
Ibs. of corn and cob meal, 6 Ibs. of wheat bran and 6 Ibs.
of oil meal per day. The records show that the flow of
milk kept up to 16 Ibs. per day in February in case of
this cow, but fell to 14 Ibs. in March and April, the
average test of the milk being, in February 3. 6, in March
3.8, and in April 4.0 per cent. The milk was, therefore,
somewhat richer in April than in December, but not
more so than is found normally, owing to the progress
of the period of lactation.

172. Influence of pasture on the quality of milk. On
May 1, the cows were given luxurient pasture feed and
no grain; a slight increase in the average amount of milk
produced per day followed, with a reduction in the test,
this being 3.8 per cent, the same as in December.

During all these changes of feed, there was, therefore,
not much change in the richness of the milk, while the
flow of milk was increased by the heavy grain-feeding
for several months, as well as by the change from grain
feeding in the barn to pasture feed with no grain.1

173. The increase which has often been observed in the
amount of butter produced by a cow, as a result of a
change in feed, doubtless as a rule comes from the fact
that more, but not richer milk is produced. The quality
of milk which a cow produces is as natural to her as is
the color of her hair and is not materially changed by
any special system of normal feeding.2

1 For further data on this point, see Cornell (N. Y.) exp. sta., bulletins
13, 22, 36 and 49; N. D. exp. sta., bull. 16; Kansas exp. sta., report, 1888;
Hoard's Dairyman, 1896, pp. 924-5.

2 On this point numerous discussions have in recent years taken place
in the agricultural press of this and foreign countries, and the subject has
been under debate at nearly every gathering of farmers where feeding

10

146 Testing Milk and Its Products.

174. Method of improving the quality of milk. The qual-
ity of the milk produced by a herd can generally be im-
proved by selection and breeding, i. e., by disposing of
the cows giving poor milk, say below 3 per cent, of fat,
and by breeding to pure-bred or high-grade bulls of a
strain that is known to produce rich milk. This method
cannot work wonders in a day, or even in a year, but it
is the only certain way we have to improve the quality
of the milk produced by our cows.

It may be well in this connection to call attention to
the fact that the quality of the milk which a cow pro-
duces is only one side of the question; the quantity is
another, and an equally important one. Much less dissat-
isfaction and grumbling about low tests among patrons of
creameries and cheese factories would arise if this fact
was more generally kept in mind. A cow giving 3 per
cent, milk should not be condemned because her milk
does not test ,5 per cent. ; she may give twice as much milk

problems have been considered. Many farmers are firm in their belief
that butter fat can be "fed into" the milk of a cow, and would take excep-
tion to the conclusion drawn in the preceding. The results of careful in-
vestigations by our best dairy authorities point conclusively, however, in
the direction stated, and the evidence on this point is overwhelmingly
against the opinion that the fat content of the milk can be materially and
for any length of time increased by changes in the system of feeding. The
most conclusive evidence in this line is perhaps the Danish co-operative
cow-feeding experiments, conducted during the past ten years with over
2,000 cows in all. The conclusion arrived at by the director of the Copen-
hagen experiment station, under whose supervision the experiments have
been conducted, has been repeatedly stated in the published reports of the
station: that the changes of feed made in the different lots of cows included
in the experiments have had practically no influence on the chemical
composition (the fat content) of the milk produced. In these experiments
grain feeds have been fed against roots, against oil cake, and against wheat
bran or shorts; grain and oil cake have furthermore been fed against roots,
and roots have been given as an additional feed to the standard rations
tried,— in all cases with the same negative results so far as changes in the
fat contents of the milk produced are concerned.

Testing Milk on the Farm. 147

per day as a 5 per cent. -cow, and will therefore produce
considerably more butter fat. The point whether or not
a cow is a persistent milker is also of primary import-
ance; a production of 300 Ibs. of butter fat during a
whole period of lactation is a rather high dairy standard,
but one reached by many herds, even as the average for
all mature cows in the herd. It should be remembered
that a high production of butter fat in the course of the
whole period of lactation is of more importance than a
very high test.

CHAPTER X.
COMPOSITE SAHPLES OF MILK.

175. Shortly after milk testing had been introduced to
some extent in creameries and cheese factories, it was

suggested by Patrick,
then of the Iowa ex-
periment station, l that
a great saving in labor
without affecting the
accuracy of the results
could be obtained by
mixing the daily sam-
ples of milk from one
source, and testing this
mixture instead of
each sample contribu-
ting thereto. Such a
mixture is called a
composite sample. The
usual methods of tak-
ing such samples at

FIG. 50. Taking test samples at in-take. creameries and cheese

factories during the past few years have been as follows:

176. Methods of taking composite samples, a. Use of
tin dipper. Either pint or quart Mason fruit jars, or milk
bottles provided with a cover, are used for receiving the
daily samples. One of these jars is supplied for each

Bulletin No. 9, May 1890.

Composite Samples of Milk. 149

patron of the factory and is labeled with his name or
number. A small quantity of preservative (bi-chromate
of potash, bi-chlorid of mercury, etc., see 188) is added
to each jar • these are placed on shelves or somewhere
within easy reach of the operator who inspects and
weighs the milk as it is received at the factory. When
all the milk delivered by a patron is poured into the
weighing can and weighed, a small portion thereof,
usually about an ounce, is put into the jar labeled with
the name or number of the patron. The samples are
conveniently taken by means of a small tin dipper hold-
ing about an ounce. This sampling is continued for a
week, ten days, or sometimes two weeks, a portion of
each patron's milk being added to his particular jar
every time he delivers milk. A test of these composite
samples takes the place of separate daily tests and gives
accurate information regarding the average quality of the
milk delivered by each patron during the period of
sampling. The weight of butter fat which each patron
brought to the factory in his milk during this time, is
obtained by multiplying the total weight of milk deliv-
ered during the sampling period by the test of the
composite sample, dividing the product by 100.

177. This method of taking composite samples has been
proved to be practically correct. It is absolutely correct
only when the same weight of milk is delivered daily by
the patron. If this is not the case, the size of the various
small samples should bear a definite relation to the milk
delivered; one-sixteen hundredth, or one two-thousandth
of the amount of milk furnished should, for instance, be
taken for the composite sample from each lot of milk.

150 Testing Milk and Its Products.

This can easily be done by means of special sampling
devices (see 179 et. seq. ). As the quantities of the milk
delivered from day to day by each patron vary but little
perhaps not exceeding 10 per cent, of the milk delivered,
the error introduced by taking a uniform sample, e. g.,
an ounce of milk, each time is, however, too small to be
worth considering in factory work, and the method of
composite sampling described is generally adopted in
separator creameries and cheese factories, where the
payment of the milk is based on its quality.

178. By this method of composite sampling each lot of
rich, medium or thin milk receives due credit for the
amount of butter fat which it contains, and errors that
might arise from testing only one day's milk at irreg-
ular intervals are avoided. In order to obtain reliable
results by composite sampling it is essential that each
lot of milk sampled shall be sweet and in good condition,
containing no lumps of curdled milk or butter granules.
The m'ilk is of course always evenly mixed before the
sample is taken.

179. b. Drip sample. Composite samples are sometimes
taken at creameries and cheese factories by collecting in
a small dish the milk that drips through a fine hole or
tube placed in the conductor spout through which the
milk runs from the weighing can to the receiving vat or
tank. A small portion of the drip collected each day is
placed in the composite sample jar, or the quantity of
drip is regulated so that all of it may be taken. In the
latter case the quantity of milk delivered will enter into
the composite sampling as well as its quality, and the
sample from, say 200 Ibs. of milk will be twice as large
as the sample frem 100 Ibs. of milk.

Composite Samples of Milk. 151

Where it is desired to vary the size of the samples
according to the quantity of milk delivered from day to
day, it is necessary to adopt the method of collecting
drip samples, just explained, or to make use of special
sampling devices, like the "milk thief" or a Scovell
sampling tube. The principle of both these tubes is the
same, and it will be sufficient to describe here only one.

180. c. The Scovell sampling tube. This convenient
device for sampling milk1 (fig. 51) consists of a drawn
copper or brass tube, one-half to one inch in diameter;
it is open at both ends, the lower end sliding snugly in a
cap provided with three elliptical openings at

the side, through which the milk is admitted.
The milk to be sampled is poured into a cylin-
drical pail, or the factory weighing can, and the
tube, with the cap set so that the apertures are
left open, is lowered into the milk until it touches
the bottom of the can. The tube will be filled
instantly to the level of the milk in the can and
is then pushed down against the bottom of the
can, thereby closing the apertures of the cap and
confining within the tube a column of milk rep-
senting exactly the quality of the milk in the
can and forming an aliquot part thereof. The
milk in the sampling tube is then emptied into
the composite sample jar by turning the tube
upside down.

181. If the diameter of the sampling pail used
is 8 inches, and that of the sampling tube \ inch
(these dimensions will be found convenient in
sampling milk from single cows), then the quan-

i Kentucky experiment station, 8th report, pp. xxvi-xxxii.

152 Testing Milk and Its Products.

tity of milk secured in the tube will always stand in the
ratio to that of the milk in the pail, of (J)2 to 82,1
that is, very nearly 1 to 256; no matter how much or
how little milk there is in the pail, the sample will
represent T J-g- part of the milk. For composite sampling
of the milk of single cows, this proportion will prove
about right; if more milk is wanted for a sub-sample,
dip twice, or pour the milk to be sampled into a can of
smaller diameter. If the mixed milk from a number of
cows is to be sampled, a wider sampling can is used. By
adjusting the diameters of the tube and the can, any de-
sired proportion of milk can be obtained in the sample.

For factory sampling, with a weighing can, 26 inches
in diameter, a tube three-quarters of an inch in diameter
will be found of proper dimensions.

In using any one of these tubes, the size of the sample
is regulated by the amount of milk in the sampling can,
as the milk always rises to the same height in the tube
as iii the can. In all cases cylindrical sampling cans
must be used.

182. The sampling tube will furnish a correct sample
of the milk in the can, even if this has been left stand-
ing for some time; it is better, however, to take out the
sample soon after the milk has been poured into the can,
as the possible error of cream adhering to the side of the
sampling tube is then avoided.

183. The accuracy of the sampling of milk by means
of the Scovell tube was proved beyond dispute in the

i The contents of a cylinder are represented by the formula 7Tr2h, r
being the radius of the cylinder, and h its height. The relation between
two cylinders of the same height, the radii of which are R and r, is there-
fore as 7TR2h to 7Tr2h, or as R2 to r2.

Composite Samples of Milk. 153

breed tests conducted at the World's Columbian Exposi-
tion in 1893, in which tests this method was adopted for
sampling the milk produced by the single cows and the
different herds.1 The data obiained in these breed tests
also furnish abundant proof of the accuracy of the Bab-
cock test.

184. d. The Equity milk sampler. This sampling tube,
designed by Kolarik and Werder, is attached to the
milk weighing can. After lowering
it into the milk the tube is opened at
the bottom by pressing on the top,
fig. 52. The tube then fills to the
height of the milk in the can and is
raised by sliding it through the collar
that holds it in place. The milk in
the tube is then discharged into the r^IJfV-
samplejar, fig. 53. // p

185. e. Composite sampling with a FIG. 53.
Lowering „ one.thjrd samp|e pipette." Milk is Discbarf in*

tube into sample

milk, sometimes sampled directly from the into jar.
weighing can into the Babcock test bottle by means of a
pipette holding 5.87 cc., which is one third the size of
the regular pipette. This quantity is measured into the
test bottle from three successive lots of milk from the
same patron and the test then made in the ordinary
manner. In this way one test shows the average com-
position of the milk delivered during three successive
days or deliveries. When this method is adopted, as
many test bottles are provided as there are patrons;

i Kentucky experiment station, 8th report, pp. xxx-xxxi. Another
form of a milk sampling tube in use at the Iowa experiment station was
described and illustrated by Mr. Eckles in Breeder's Gazette, May 19, 1897.

154

Testing Milk and Its Products.

there is no need of using any preservatives for the milk
in this case. Fig. 54 shows a convenient rack for hold-
ing the test bottles used
in composite sampling
with a " one-third sample
pipette."

Accurate results can be
obtained by this method
of sampling, if care is
taken in measuring out
the inilk, and if it is not
frozen or contains lumps
of cream. It is doubtful
if the method has any
advantage over the usual

FIG. 54. Test-bottle rack for use in method of Composite Samp-
creameries and cheese factories. ling. If milk is delivered

daily and each lot is sampled with the one-third pipette,
twice or three times the number of tests are required as
when composite samples are taken in jars and tested
once every week or ten days. This method furthermore
takes a little more time in the daily sampling than the
other, as the quantity of milk must be measured out
accurately each time. If the test bottle is accidentally
broken or some milk spilled, the opportunity of ascer-
taining the fat content of the milk delivered during the
three days is lost; if a similar accident should occur in
testing composite samples collected in jars, another test
can readily be made.

186. Accuracy of the described methods of sampling. An
experiment made at the Wisconsin Dairy School may
here be cited, showing that concordant results will be

Composite Samples of Milk. 155

obtained by the use of the drip sampling method and the
Scovell tube. Two composite samples were taken from
fifty different lots of milk, amounting to about 6,000 Ibs.
in the aggregate. One sample was taken of the drip
from a hole in the conductor spout through which the
milk passed from the weighing can; the other was taken
from the weighing can by means of a Scovell sampling
tube. The following percentages of fat were found in
each of these samples:1

Gravimetric
Babcock test. analysis. .

Drip composite sample 4.0 per cent. 4.04 per cent.

Scovell tube composite sample.. 4.0 per cent. 4.06*per cent.

PRESERVATIVES FOR COMPOSITE SAMPLES.

187. When milk is kept any length of time under ordi-
nary conditions, it will soon turn sour and become lop-
pered, and further decomposition shortly sets in, which
renders the sampling of the milk both difficult and un-
satisfactory (19). The changes which occur when milk
sours are due to the formation of lactic acid by the action
of bacteria on milk sugar; the acid coagulates the casein
of the milk, but does not destroy or attack the butter
fat (32). The period during which milk will remain in
an apparently sweet or fresh condition varies with the
temperature at which it is kept, and with the cleanliness
of the milk. It will not generally remain sweet longer
than two days at the outside, at ordinary summer or
room temperature.

In order to preserve composite samples of milk in a
proper condition for testing, some chemical which will

i See also 189 et seq.

156 Testing Milk and Its Products.

check or prevent the fermentation of the milk must be
added to it. A number of substances have been proposed
for this purpose.

188. Bi-chromate of potash. This preservative is, in
the opinion of the authors, to be preferred, on account of
its relative harmlessness, its cheapness and efficiency.
The bi-chromate method for preserving samples of milk
was proposed by Mr. J. A. Alen, city chemist of Gothen-
burg, Sweden, in 1892, l and has been generally adopted
in dairy regions in this country and abroad. While not
perfectly harmless, the bi-chromate is not a violent poison
like other chemicals proposed for this purpose, and no
accidents are liable to result from its use; at least none
have been known to the writers to occur during the years
that it has been used in creameries or dairies as a pre-
serving agent.

189. The quantity of bi-chromate necessary for preserv-
ing half a pint to a pint of milk for a period of one or
two weeks is about one-half-gram (nearly 8 grains). As
there are about 900 half-grams in a pound, this quantity
will suffice for nine weeks in a creamery having one
hundred patrons, if tests are made once a week, or for
three months (90 days) if tests are made every ten days.

According to Winton and Ogden,2 a .22-inch pistol
cartridge shell cut to J inch long, or a .32-inch calibre
shell cut to J inch long, when loosely filled, will hold
enough powdered bi-chromate to preserve Jpint, and a
.32-inch calibre shell cut to \ inch long will hold enough
to preserve one pint. These shells may be conveniently

1 Biedermann's Centralblatt, 1892, p. 549.

2 Connecticut experiment station, report for 1884, p. 222.

Composite Samples of Milk. 157

handled by soldering to them a piece of stiff wire which
serves as a handle. The amount of bi-chromate placed
in each composite sample jar would fill about half the
space representing one per cent, in the neck of the Bab-
cock milk test bottle.

190. The first portions of milk added to the composite
sample jars containing the specified amount of bi-chro-
mate will be colored almost red, but as more milk is
added, day by day, its color will become lighter yellow.
The complete sample should have a light straw color;
such samples are most easily mixed with acid when
tested. If more bi-chromate is used, the solution of the
casein in the acid is rendered difficult and requires more
persistent shaking. Bi-chromate can be bought at drug
stores or from dairy supply dealers at about 30 cents a
pound and will cost about 25 cents a pound at wholesale.
Powdered bi-chromate of potash should be ordered, and
not crystals, as the latter dissolve only slowly in the milk.
Farrington's bi-chromate tablets contain the correct
quantity of preservative for a quart sample, and will be
found convenient.

191. Other preservatives for composite samples. Among
other substances recommended for use in butter or cheese
factories as milk preservatives for composite samples are
formalin, boracic-acid compounds, chloroform, carbon
bi-sulfid,1 copper ammonium sulfate, sodium fluorid,
ammonia glycerin (sp. gr., 1.031) and mixtures contain-
ing mercuric chlorid (corrosive sublimate) with anilin
color (rosanilin).2 The coloring matter in the latter

1 Delaware experiment station, eighth report, 1896, which also see for
trials with a large number of different preservatives.

2 Iowa experiment station, bulletins 9, 11, 32.

158 Testing Milk and Its Products.

compounds is added to give a rose color to the sample
preserved, thus showing that the milk is not fit for
consumption; the bi-chromate giving naturally a yellow
color to the milk, renders unnecessary the addition of any
special coloring matter.

None of the substances mentioned are as cheap as bi-
chromate or more effective for factory purposes when
the milk is to be kept not to exceed two or
three weeks. The compounds containing corrosive
sublimate are violent poisons and must always be handled
with the greatest care, lest they get into the hands of
children or persons unfamiliar with their poisonous
properties; they will preserve the milk longer than bi-
chromate when applied in sufficient quantities, but for
factory use the latter is amply effective and has, as
already stated, the advantage in several respects.

192. Care of composite samples. The composite sam-
ple jars should be kept covered to prevent loss by
evaporation, and in a cool, dark place, or at least out of
direct sunlight; the chromic acid formed by the reducing
influence of light on chrornate solutions produces a leath-
ery cream which is very difficultly dissolved in sulfuric
acid.

A coating of white shellac has been suggested to pro-
tect the labels of the composite sample jars. The shellac
is applied after the names of the patrons have been
written on the labels, and when these have been put on
the jars. Gummed labels, lx2J inches, answer this pur-
pose well.

In keeping the milk from day to day, care should be
taken that the cream forming on the milk does not stick

Composite Samples of Milk. 159

to the sides of the jars in patches abo^e the level of the
milk. Unless the daily handling of the jars and the
addition of fresh portions of milk be done with sufficient
care, the cream will become lumpy and will dry on the
sides of the jars. In some cases it is nearly impossible
to evenly distribute this dried cream through the entire
sample so as to make the composite sample a true repre-
sentative of the different lots of milk from which it has
been taken.

193. Every time a new portion of milk is added to the
jar this should be given a gentle horizontal rotary mo-
tion, thereby mixing the cream already formed in the
jar with the milk and rinsing off the cream sticking to
its side. This manipulation also prevents the surface of
the milk from becoming covered with a layer of partially
dried leathery cream.

Composite samples having patches of dried cream on
the inside of the jar are the result of carelessness or
ignorance on the part of the operator. If proper atten-
tion is given to the daily handling of the composite sam-
ples, the cream formed in the jars can without difficulty
again be evenly mixed with the milk.

194. Fallacy of averaging percentages. A composite
sample of milk should represent the average quality of
the various lots of milk of which it is made up. This
will invariably be true if a definite aliquot portion or
fraction of the different lots of milk is taken. If the
weights of, say ten different lots of milk are added to-
gether and the sum divided by ten, the quotient will
represent the average weight per lot of milk, but an
average of the tests of the different lots obtained in this

160

Testing Milk and Its Products.

way may not be the correct average test of the entire
quantity of milk. The accuracy of such an average
figure will depend on the uniformity in the composition
and weights of the ten lots of milk. When there is no
uniformity, the weights of the different lots of milk as
well as their tests must be considered. The following
example illustrates the difference between the arithmet-
ical average of a number of single tests and the true
average test of the various lots.

Methods of calculating average percentages.

1. Milk varying in weights and tests.

II. Milk of uniform weights and tests.

LOT.

i&

P

^0

Test
of milk.

II
P

LOT.

**

?a
**

Test
of milk.

Weight
of fat.

I

Ibs.

120
570
360
55

82

per ct.

3.5
5.0
5.2
3.0
4.0

Ibs.

4.2

28.5
18.7
1.6
3.2

I

Ibs.

250
225
240
238
234

per ct.

4.2
4.0
4.3
4.1
4.4

Ibs.

10.5
9.0
10.3
9.7
10.3

II

II
Ill

Ill

IV

IV

V

V
Total

Total

1187
237

4.14
4 731

56.2
11.24

1187
237

4.20

4 222

49.8
10.0

Average

True average
test

Average

True average
test

1 56.2X100

=4.73.

49.8X100

=4.22.

1187 1187

195. The figures given in the table show that when
the different lots of milk vary in test and weight, as in
the first case, the correct average test of the 1187 Ibs. of
milk is not found by dividing the sum of these tests by
five, which would give 4.14 per cent.; but the percentage
which 56.2 (the total amount of fat in the mixed milk,
in Ibs. ) is of 1187 (the total amount of milk in Ibs. ) is

Composite Samples of Milk. 161

4.73, and this is the correct average test of the mixed
milk made up of the five different lots.

In the second case, the variations in both the weights
of the different lots of milk and their tests, are compara-
tively small, and both methods of calculation give there-
fore practically the same average test; but also in this
case, the correct average test is found by dividing the
total amount of fat by the total quantity of milk, making
4.22 per cent., instead of 4.20 per cent., which is the
aritmetical mean of the five tests. The quantities of
milk in the various lots do not enter into the calculation
of the latter.1

196. The second example represents more nearly than
the first one the actual conditions met with at creameries
and cheese factories. As a rule the mixed milk from a
herd of cows does not vary more in total weight or tests,
within a short period of time like one to two weeks, than
the figures given in this example. On account of this
fact, samples taken, for instance, with a small dipper may
give perfectly satisfactory results to all parties concerned.
If the different lots of milk varied in weight and test
from day to day, as shown in the first case, it would be
necessary to use a "milk thief" or a Scovell sampling
tube for taking the composite samples; the size of each
of the samples taken would then represent an exact ali-
quot portion of the various lots of milk (180).

197. A patron's dilemma. The following incident will further
explain the difficulties met in calculating the average tests of
different lots of milk.

i In the experiment given on p. 137, the arithmetical mean of the tests
given is 5.15 per cent., while the true average fat content of the milk is 4.85
per cent.
11

162 Testing Milk and Its Products.

The weekly composite sample of the milk supplied by a
creamery patron from his herd of 21 cows tested 4.0 per cent,
fat. One day the farmer brought to the creamery a sample of
the morning's milk from each of his cows, and had them tested;
after adding the tests together and dividing the sum by 21, he
obtained an average figure of 5. 1 per cent, of fat. From this he
concluded that the average test of the milk from his cows ought
to be 5.1, instead of 4.0, and naturally asked for an explanation.
198. The first thing done was to show him that while 5.1 was
the correct average of the figures representing the tests of his
twenty-one cows, it was not a correct average test of the mixed
milk of all his cows, as he had not considered in calculating
this average, the quantities of milk yielded by each cow; the
following illustration was used:

Cow No. 1, yield 25 Ibs. of milk, test 3.6 per cent.=0.9 Ibs. of butter fat.

Cow No. 2, yield 6 Ibs. of milk, test 5.0 per cent. =0.3 Ibs. of butter fat.

Total 31 ibs. 2)8.0 1.2 Ibs.

4.3 per cent.

The two cows gave 31 Ibs. of milk containing 1.2 Ibs. of fat;
the test of the mixed milk would therefore not be 4.3 per cent.
(^i5^), but L2g1100 =3.87 per cent. If the fat in the mixed
milk was calculated by the average figure 4.3 percent., 1.33 Ibs.
of fat would be obtained, i. e., 0.13 Ibs. more than the cows
produced.

In order to further demonstrate the actual composition of
the mixed milk of the twenty-one cows, the milk of each cow
was weighed and tested at each of the two milkingsof one day.
The weights and tests showed that the cows produced the fol-
lowing total number of pounds of milk and of fat:

Morning milking, 113.3 Ibs. of milk, containing 5. 17 Ibs. of fat.

Night milking, 130.9 Ibs. of milk, containing 4.98 Ibs. of fat.

The morning milk therefore contained 5111^X3100=4.56 per
cent, of fat, and the night milk^|^=3.80 per cent, of fat.

The sum of the morning and night milkings gave: milk,
244.2 Ibs., fat 10.15 Ibs. The mixed morning and night milk,
therefore, contained 10'^X210°=4.1 per cent, of fat. This is the

Composite Samples of Milk. 163

true average test of the morning and night milkiugs of these
twenty-one cows, as found by weighing and testing separately
the milk of each cow at both milkings.

199. The total milk was strained into a large can at the farm,
both in the morning and in the evening, A sample of the
mixed milk was in each case taken with a long-handled dipper
as soon as the milkiugs were finished. When the cans of milk
were delivered at the creamery, a sample of each was taken
with a Scovell sampling tube. The tests of these four samples
are given below, together with the results from the individual
tests:

Morning milk. Night milk.

Sample taken at the farm, with

dipper 4.4 per cent. 3.8 per cent.

Sample taken at creamery, with

Scovell tube 4.5 per cent. 3.7 per cent.

Calculated from weights and tests

of milk from each cow 4.5 per cent. 3.8 per cent.

The figures given show that practically uniform tests were
obtained by the different methods of sampling.

The sum of the weights of the milk from the different cows
was as follows:

Morning milk. Night milk. Daily milk.

Total milk produced 113.3 Ibs. 130.9 Ibs. 244.2 Ibs.

Milk in samples 12.3 Ibs. 8:9 Ibs 21. 2 Ibs.

Milk for family use 2.5 Ibs l 2.5 Ibs.

Milk taken to creamery.. 98.5 Ibs. 122.0 Ibs. 220.5 Ibs.
It has already been shown from the weights and tests of each
cow's milk that the herd milk contained 4.1 per cent, of fat.
Multiplying the total milk delivered at the creamery, 220.5 Ibs.,
by .041 gives 9.04 Ibs. of fat. The morning and night milkings,
which were weighed and tested separately, contained the fol-
lowing quantities of butter fat:

Morning milk 98.5 Ibs. X. 045=4.43 Ibs. of butter fat.

Night milk 122.0 Ibs. X. 038=4. 63 Ibs. of butter fat.

Total 220.5 Ibs. 9.06 Ibs.

164 Testing Milk and Its Products.

By weighing, sampling and testing separately the morning
and night milkings of twenty-one cows, deducting the weight
of milk in the samples and what was taken out for family use,
it was found that 9.04 Ibs. of butter fat was sent to the cream-
ery. The weights and tests of this same milk when delivered
at the creamery, gave 9.06 Ibs. of butter fat.

200. This example furnishes an excellent illustration of the
accuracy of the Babcock test and of the closeness of results
which may be obtained at creameries when proper care is taken
in weighing, sampling and testing the milk. Similar demon-
strations may be made by any factory operator, and with
equally satisfactory results, provided the work is carefully done.

CHAPTEE XL

CREAfl TESTING AT CREAfl=QATHERINQ
CREAflERIES.

201. The cream delivered at gathered- cream factories
is now in many localities tested by the Babcock test, and
this has been adopted as a basis of paying for the cream
in the same manner as milk is paid for at separator
creameries. It has been found to be more satisfactory to
both cream buyer and seller, than either the oil-test
churn or the space (or guage) systems which have been
used for this purpose in the past.

The details of the application of the Babcock test to
the practical work at cream-gathering creameries have
been carefully investigated by Winton and Ogden in
Connecticut,1 Bartlett in Maine,2 and Lindsay in Massa-
chusetts,3 and we also owe to the labors of these chemists
much information concerning the present workings of
other systems of paying for the cream delivered at
creameries.

202. The space system. Numerous tests have shown
that one space or gauge of cream does not contain a defi-
nite, uniform amount of fat. In over 100 comparisons
made by Winton it was found that one space of cream4

iConn. experiment station (New Haven), bull. No. 108 and 119; report
1894, pp. 214-244.

2 Maine experiment station, bull. 3 and 4 (S. S.).

3 Hatch experiment station, report 1894, pp. 92-103; 1895, pp. 67-70.

4 The space is the volume of a cylinder, 8% inches in diameter and J2 of
an inch high. The number of spaces in each can of milk is read off before
skimming by means of a scale marked on a strip of glass in the side of the
can (Conn. exp. sta., bull. No. 119).

166

Testing Milk and Its Products.

contained from .072 to .170 Ibs. of butter fat, or on the
average .13 Ibs., and the number of spaces required to
make one pound of butter varied from 5.01 to 11.72. It
is also claimed that in the winter season when the cream
is gathered at long intervals, like once a week, it is
necessary for the buyer to accept the seller's statement
of the record of the number of cream spaces which he

FIG. 55. The oil-test churn.

furnishes, since the cream cannot be left in the creaming
cans for so long a time. These objections to the space
system apply only to the method of paying for the cream,
and not to the manner in which the cream is obtained.

203. The oil-test churn. As stated in the introduction,
the oil-test churn (fig. 55) has been used quite extensively
among gathered-creain factories; this system is based on

Cream Testing at Creameries.

167

rmnmmm

the number of creamery inches of cream which the
various patrons deliver to the factory; one inch of cream
contains 113 cubic inches.1 The driver pours the patron's
cream into his 12-inch gathering pail, measures it with
his rule and records the depth of the cream in the can,
in inches and tenths of an inch. The cream is then stirred
thoroughly with a ladle or a stout dipper, and a sample
is taken by filling a test tube from the sample case, to the
graduation mark by means of a small conical dipper pro-
vided with a lip. A driver's case contains either two or
three "cards," holding fifteen test tubes each (see fig. 56).

The tubes as filled A

are placed in the
case and the cor-
responding number
is in each instance
recorded in front of
the patron's name
together with the
number of inches
of cream furnished
by him.

On arrival at the

Creamery the tin FIG. 56. Cream-gatherer's sample case.

cards holding the tubes are placed in a vessel filled with
water of the temperature wanted for churning (say, 60°
in summer and 65° to 70° in winter.) When ready for
churning they are placed in the oil-test churn, the coyer
of the churn put on, and the samples of cream churned

i I. e., a layer of cream one inch deep in a 12-inch pail; two inches in
an 8-inch pail contains 100.531 cubic inches, two inches in an 8%-inch pail
110.18 cubic inches, and two inches in an 8%-inch pail 113.49 cubic inches.

CARD DRIVERS CASE

168 Testing Milk and Its Products.

to butter. On the completion of the churning, the cards
are transferred to water of 175-190° Fahr., where they
are left for at least ten minutes to melt the butter and
"cook the butter milk into a curd." The oil will now
be seen mixed all through the mass. The test tubes are
then re-tempered to churning temperature and churned
again, by which process the curd is broken into fine
particles, which, when the butter is re- melted, will settle
to the bottom. The butter is melted after the second
churning by placing the tubes in water at 150-175° F.,
allowing them to remain therein for at least twenty min-
utes. Some samples must be churned three or four times
before a good separation of oil is obtained. A clear
separation of oil is often facilitated by adding a little
sulfuric acid to the tubes.

The length of the column of liquid butter fat is deter-
mined by means of a special rule for measuring the but-
ter oil; this rule shows the number of pounds and tenths
of a pound of butter which an inch of cream will make;
the first tenth of a pound on the rule is divided into five
equal parts, so that measurements may be made to two-
hundredths of a pound. The melted fat is measured with
the rule, by raising the tin card holding the bottles, to
about the height of the eye; the reading is recorded on
the driver's tablet under Test per inch, opposite the num-
ber of the particular patron. The test per inch multi-
plied by the inches and tenths of an inch of cream sup-
plied will give the butter yield in pounds, with which
the patron will be credited on the books of the creamery.

204. The objection to this system of ascertaining the
quality of cream delivered by different patrons lies in

Or earn Testing at Creameries. 169

the fact that it determines the churnable fat, and not the
total fat of the cream; the amount obtained of the former
depends on many conditions beyond the control of the
patron, viz., the consistency, acidity and temperature of
the cream, the size of the churn or churning vessel, etc.
The same reasons which caused the churn to be replaced
by methods of determining the total fat of the milk, in
the testing of cows among dairymen and breeders, have
gradually brought about the abandonment of the oil test
in creameries and the adoption of the Babcock test in
its place.

205. The Babcock test for cream. Both the space sys-
tem and the oil-test churn used for estimating the quality
of cream at creameries have now largely been replaced
by the Babcock test in the more progressive creameries
in this country, and composite samples of cream are
collected and tested in a similar manner as is done with
milk at separator creameries and cheese factories.

A very satisfactory method of arrangements for work-
ing the Babcock test, in use in many eastern creameries,
is described by Winton and Ogden in the Connecticut
report previously referred to. The cream gatherer who
collects the cream in large cream cans is supplied with
a spring balance (1, see Fig. 57), pail for sampling and
weighing the cream (2), sampling tube (3), and collecting
bottles (5). At each patron's farm he takes from his
wagon the sampling pail and tube, the scales, and one
small collecting bottle. He should find in the dairy of
the patron the cans of perfectly sweet cream, kept at a
temperature of 40° to 50° F., and protected from dirt and
bad odors. Either sour or frozen cream must be rejected.

170

Testing Milk and Its Products.

11 8 7 5

FIG. 57. Outfit for cream testing by the Babcock test at gathered-
cream factories.

The patrpn's number should be painted in some conspic-
uous place near the cream cans in his dairy house. The
gatherer hangs the scale on a hook near the cream to be
collected; the scale should be so made that the hand of
the dial will stand at zero when the empty pail is hung

Testing Cream at Creameries. 171

on it. The cream is then poured at least twice from one
can to another in order to mix it thoroughly.1

206. When properly mixed, the cream is poured into
the weighing pail and is weighed and sampled. The
authors give the following description of the cream sam-
pling tube used, and directions for sampling and weigh-
ing the cream:

"Sampling Tube.— This tube, devised by Mr. Ogden, is of
stout brass, about ^ of an inch thick, and a few inches longer
than the weighing pail which is used with it. On the upper
end, a small brass stop-cock of the same bore is fastened. It
should be nickel plated inside and out, to keep the metal
smooth and free from corrosion. These tubes may be obtained
from less than f36 to over J inch bore. The greater the diameter
of the weighing pail, the wider should be the bore of the tube.
For use with pails 8 inches in diameter, a /<, inch bore sampling
tube will serve the purpose, but when the pail has a diameter
of 9 or more inches, a tube with a bore of \ inch or more should
be used. It must be borne in mind that doubling the diameter
of the pail, or of the sampling tube, increases its capacity
fourfold.

"The tube when not in use should be kept in an upright
position to permit draining.

"Sampling and Weighing. — Lower the sampling tube, cock
end up, with the cock open, to the bottom of the weighing pail
which holds the mixed cream. When it is filled, raise it out of
the liquid and allow it to drain for a few seconds. By this
means the tube is rinsed with the cream to be sampled and any

i The necessity of care in mixing the cream is shown by the following
illustration given by the authors referred to:

Per cent, of fat in cream which stood for %lt hours.

Sample drawn
Surface. Bottom. with sampling tube.

Not mixed 28.00 5.00 19.25

Poured once 2375 22.00 22.50

Poured twice 22.25

172 Testing Milk and Its Products.

traces of cream adhering to the tube from previous use are
removed. With the cock still opeu, slowly lower the sampling
tube to the bottom of the cream pail. After allowing a moment
for the cream to rise in the tube to the same height as in the
pail, close the cock and raise the sampler carefully out of the
cream. As long as the cock is closed, the cream in the tube
will not flow out, unless the tube is strongly jarred. Allow the
cream adhering to the outside of the tube to drain off for a few
seconds, then put the lower end into the 1 to 1J oz. wide-mouth
glass collecting bottle which bears the patron's number on its
cork, and open the cork. The cream will then flow out of the
sampler into the bottle, which is afterwards securely corked and
put into the cream gatherer's case. Immediately weigh the
cream in the cream pail to the quarter or half pound, as may
be judged expedient, and record the weight.

"If the patron has more than one pailful, repeat with each
pailful the operation of sampling and weighing, putting all the
samples in one and the same bottle. Weigh alt cream collected
in, one and the same sampling pail and draw a sample from
each separate portion weighed."

207. After sampling and weighing each patron's cream
it is poured into the driver's large can, and the sample
bottles are carried in a case to the creamery where the
contents of each bottle is poured into the composite sam-
ple jar of the particular patron. The samples of cream
in the small bottles, besides furnishing the means of test-
ing the richness of the cream, give the creamery owner
or manager an opportunity to inspect the flavor of each
lot of cream, and the condition in which it has been kept
by the various patrons. Potassium bi-chromate is placed
in the composite sample jars, and these are cared for and
tested in the same manner as composite samples of milk
(192).

208. The collecting bottles should be cleaned with
cold, and afterwards with hot water, as soon as they are

Testing Cream at Creameries. 173

emptied, and before a film of cream dries on them.
When washed and dried, these bottles are placed in the
cases, ready for the next collecting trip. There can be
no confusion of bottles since the corks and not the bottles
are marked with the numbers of the respective patrons.

209. When cream is bought by this system of testing
composite samples, the patrons are paid for the number
of pounds of butter fat contained in their cream, in ex-
actly the same way as milk is paid for at separator
creameries. It makes no difference how thick or how
thin the cream may be, or how much skim milk is left in
the cream when brought to the factory. Eighty pounds
of cream containing 15 per cent, of fat is worth no more
or less than 48 pounds of cream testing 25 per cent. ; in
either case 12 pounds of pure butter fat is delivered.
This will make the same amount of butter in either case,
viz., toward 14 Ibs., and both patrons should therefore
receive the same amount of money.

There is a small difference in the value of the two lots
of cream to the creamery owner or the butter maker, in
favor of the richer cream, both because its smaller bulk
makes the transportation and handling expenses lighter,
and because slightly less butter fat will be lost in the
butter milk, a smaller quantity of this being obtained
from the richer cream. But it is doubtful if the differences
thus occurring are of sufficient importance to be noticed
under ordinary creamery conditions; the example selected
presents an extreme case of variation in the fat content
of cream. A trial of this system at five Connecticut
creameries, supplied mostly with Cooley cream, by over
175 patrons, showed that the average composition of the

174 Testing Milk and Its Products.

cream from the different patrons varied only from 16.9
to 19. 8 per cent. fat. The cream of some patrons on cer-
tain days contained only 9.5 per cent, of fat, and other
patrons at times had as high a test as 30 per cent., but
these great differences largely disappeared when the
average quality of the cream delivered during a period
of time, like a month or more, was considered.

210. Smaller differences in the composition of cream
will, however, always occur, even if the same system of
setting the milk, like the cold deep-setting process, is
used and the water is kept at the same temperature at
all times. This is due to differences in the composition
of the milk and its creaming quality; whether largely
from fresh cows or from late milkers; whether kept
standing for a time before being set or submerged in the
creamer immediately after milking and straining; diam-
eter of creaming cans, etc. Bartlett states1 that the per-
centage of fat in the cream from the same cows may be
increased ten per cent, or more by keeping the water at
70° instead of at 40° F. The higher temperature will
give the richer cream, but the separation will not be so
complete, since a richer skim milk is obtained from the
milk set at this temperature. Separator cream is not
materially influenced by the conditions mentioned, as
the separator can be regulated to deliver cream of nearly
uniform richness from all kinds of sweet milk.

211. At creameries where both milk and cream are de-
livered, somewhat of an injustice is done to patrons de-
livering cream, by paying for the amounts of butter fat
furnished by the different patrons. By multiplying the

i Maine experiment station, bulletin No. 3 (8. S.)

Testing Cream at Creameries. 175

cream fat by 1.03 (or by 1.0441), the value of his pro-
ducts to the creamery is taken into proper account, and
justice is done to all parties concerned2 (238).

iSee Spillman, Dairy and Creamery, Chicago, April 1, 1899.
2 This subject is discussed in detail in. the 17th Annual Report of Wis.
Experiment Station, pp. 90-92.

\

CHAPTEE XII.
CALCULATION OF BUTTER AND CHEESE YIELD.

A. — CALCULATION OF YIELD OF BUTTER.

212. Butter-fat test and yield of butter. The Babcock
test shows the amount of pure butter fat contained in a
sample of milk or other dairy products. The butter ob-
tained by churning cream or milk contains, in addition
to pure butter fat, a certain amount of water, salt and
curd. While an accurate milk test gives the total quan-
tity of butter fat found in the sample of milk or cream
tested, the churn cannot be depended upon either to
leave the same amount of butter fat in the butter milk or
to include the same amount of water, salt and curd in the
butter at each churning.

If a quantity of milk, say 3,000 Ibs., be thoroughly
mixed in a vat, and then divided into half a dozen equal
portions, a Babcock test of the different lots will show
the same percentage of butter fat in each portion. If, on
the other hand, each of these lots be skimmed, and the
cream ripened in different vats and churned separately,
the same weight of butter from each lot of 500 Ibs. of
milk will not be obtained, even by the most expert but-
ter maker, or if all the operations of skimming, cream
ripening, churning, salting and butter- working were
made as nearly uniform as possible. Careful operators

Calculation of Butter- and Cheese Yield. 177

can handle the milk and cream so that very nearly the
same proportion of the fat contained in the milk is re-
covered in the butter in different churnings, but since the
water and salt in butter are held mechanically and are
not chemically combined with it, the amounts retained
by the butter are quite variable in different churnings,
especially since the laws governing the retention of water
in butter are but imperfectly understood.

213. Variations in the composition of butter. As an
illustration of the variability of butter in its composition,
the analyses made in the breed tests at the World's Fair
in 1893 may here be cited; the butter was in all cases
made by as nearly identical methods and under as uni-
form conditions as could possibly be obtained by the
skilled operators having this work in charge; the aver-
age composition of 350 samples of this butter, with upper
and lower limits, was as shown in the following table:

Composition of samples of butter, World's Fair, 1893.

Water.

Fat.

Curd.

Salt and
ash.

Sum of
water,curd,
salt and
ash.

Average of 350
analyses .. ..

Per cent.
11 57

Per cent.
8470

Per cent.
95

Per cent.

278

Per cent.
1530

Lower and upper
limits..

8 63-15 00

76 53-88 26

50-2 14

1 01-8 58

Analyses of fifty samples of creamery butter taken in
1896, from the tubs ready for market at as many Wiscon-
sin creameries, showed that no two of them were ex-
actly alike in composition, but varied within the limits
given below:1

i Wisconsin experiment station, bull. 56.
12

178 Testing Milk and Its Products.

Summary of analyses of Wisconsin creamery butter.

Water.

Fat.

Curd.

Salt
and ash.

Sum of
water, curd,
salt and ash.

Highest-

Per cent.
17.03

Per cent.
87.50

Per cent.
2 45

Per cent.
4 73

Per cent.
2295

Lowest...

9.18

77.07

.36

1 30

1250

Average

12 77

83 08

1 28

2 87

16 99

The preceding analyses show the composition of butter
made at one place where every possible effort was taken
to produce a uniform product, and of butter made at
fifty different creameries, where there was more or less
variation in the different operations of manufacture and
in the appliances and machinery used. The majority of
the samples of butter analyzed, in either case, were very
near the average composition given, but since there are
such wide variations in the composition of the butter
made by the uniform methods adopted in the World's
Fair breed tests, butter of a more uniform composition
cannot be expected from the thousands of different
creameries and private dairies which supply the general
market with butter.

The analyses of the fifty samples of creamery butter,
given above, show that the content of the butter fat
varied from 77 to over 87.5 per cent., and according to
the average of the analyses, 83 pounds of butter fat was
contained in, or made, 100 Ibs. of butter. There was,
therefore, in this case produced 20.5 per cent, more
butter than there was butter fat, since

83 : 100 : : 100 : x; therefore
100x100

x —

= 120.5,

Calculation of Butter- and Cheese Yield. 179

214. ** Overrun " of churn over test. The yield of
butter is not, however, as a rule compared with the
amount of butter fat contained in the butter, but with
the total butter fat of the whole milk from which it was
made. This " increase of the churn over the test" is
what is generally called overrun in creameries.

The overrun obtained in different creameries, or even
in the same creameries at different times, will be found
to vary considerably. When the milk is accurately
tested and the butter well worked, this overrun will vary
from 10 to 16 per cent. ; that is if a quantity of milk
contains exactly 100 Ibs. of butter fat, as found by the
Babcock test or any other accurate method of milk test-
ing, from 110 to 116 Ibs. of butter ready for market may
be made from it.

215. Factors influencing the overrun. Even under the
very best of care and attention to details, variations will
occur in the speed of the separator, in the conduct of the
ripening and churning processes, and in the condition of
the butter when the churn is stopped; hence absolutely
uniform losses of fat in skim milk and butter milk, or
the same water- and salt contents of the butter, cannot
be expected.

The overrun is influenced by two factors: the losses of
butter fat sustained in separating the milk and churning
the cream, and the gain due to the admixture of water,
salt, etc., in the manufacture of butter. Considering
first the losses of fat in skim milk and butter milk, the
separator will usually, when run at normal speed and
capacity, leave the same per cent, of fat in skim milk,
whether rich or poor milk is skimmed. An exception

180 Testing Milk and Its Products.

to this may be found in separating rich milk having
large fat globules or milk from fresh milkers, in either
of which cases the large size of the fat globules occasions
a more complete separation of fat by the centrifugal
force. But generally speaking, the statement holds good
that the total loss of fat in separator skim milk is a factor
of the quantity of milk run through the separator, rather
than of its quality. It follows from this, however, that
the relative losses of fat in skim milk will vary to some
extent according to the quality of the milk separated.
Selecting two extremes in the quality of milk, 2.5 and
6.0 per cent, of fat, there will be found, say .2 per cent,
of fat in the skim milk from either lot, provided the sep-
arator is not unduly crowded, and the separation is con-
ducted under normal conditions in each case. But .2
per cent, fat makes 8 per cent, of the total fat in the poor

(2x100 \
2 5 =^)> an(^ on^ ^ Per cem^ °f tnat i*1 the

rich milk. It takes 4000 Ibs. of the 2.5 per cent, milk
to furnish 100 Ibs. of fat, and only 1666 Ibs. of the 6 per
cent, milk; in skimming the poor milk, a loss of .2 per
cent, of fat is sustained in the skim milk from 4000 Ibs.
of milk, while in the rich milk a similar loss is sustained
in the skim milk from only 1666 Ibs. of milk.

The example gives an extreme case, and one not likely
to be met with in practice. The range in the richness of
the milk delivered by different patrons at the factory is
usually within one-half or one per cent, of fat. In such
cases the proportion of fat lost in skimming does not vary
much, e.g., in case of milk containing 3.5 and 4.0 per
cent, of fat, and variations in the overrun occurring when
the proper care in skimming, ripening and churning is

Calculation of Butter- and Cheese Yield. 181

taken, are due, therefore, primarily to differences in the
water- and salt contents of the butter made (205).

216. The losses from very poor, very rich and average
milk, as received at creameries and cheese factories, can
be traced from the following statement; this gives the
quantities of fat lost in handling milk of four grades, viz:
2.5, 3.5, 4.0 and 6.0 per cent., in case of each grade cal-
culated to a standard of 100 Ibs. of fat in the milk.

To supply 100 Ibs. of fat would require the following
amounts of the different grades of milk:
4000 Ibs. of milk testing 2.5 per cent, will contain 100 Ibs. of fat.
2857 " " " 3.5 " " " 100 " "

2500 u " " 4.0 " " u 100 " "

1666 " " " 6.0 " " " 100 " "

Assuming that the skim milk contains .2 per cent, of
fat and makes up 85 per cent, of the whole milk, that the
butter milk tests .3 per cent., and forms 10 per cent, of
the whole milk, the butter-fat record of the quantities of
different grades of milk containing 100 Ibs. of fat will
appear as follows:

Fat available for butter in different grades of milk.

Grade of milk.

Whole
milk.

Skim milk.

Butter
milk.

Total
loss.

Fat
availa-
ble for
butter.

2 5 per cent

4000 ft>.

3100 ft>.

400 ft).

Ibs.

Per cent.

2.5 per ct.

.2 per ct.

.3 per ct.

Fat

100 ft>.

* 6.8 ft).

1.2 ft)

80

92.0

3.5 per cent

2857 ft>.

2429 ft.

286 ft>.

3.5 per ct.

.2 per ct.

.3 per ct.

Fat

100 ft).

4.9 ft).

0.9 ft.

5.8

94.2

4.0 percent

2500 ft.
4 per ct.

2125 ft).
.2 per ct.

250ft..
.3 per ct.

Fat

100 ft>

4.3 ft.

0.7 ft)

5.0

95.0

6.0 per cent

1666% ft.

1417 ft.

167 ft).

6 per ct.

.2 per ct.

.3 per ct.

Fat

100 ft.

2.8 ft.

0.5 ft>.

3.3

96.7

182 Testing Milk and Its Products.

The table shows that with 2.5 per cent. -milk, there is
a loss of 6.8 Ibs. of fat in the skim milk and 1.2 Ibs. of
fat in the butter milk for every 100 Ibs. of fat in the
whole milk, or a total loss of 8.0 Ibs. from these sources.
In case of 6 per cent. -milk these losses are 2.8 Ibs. and
.5 Ibs. for skim milk and butter milk, respectively; a
total loss of 3.3 Ibs., or 4.7 Ibs. less than the losses with
the very poor milk. This difference in the losses shrinks
to only .8 pound of fat in case of 3.5 and 4.0 per ct.-milk,
when a quantity containing 100 Ibs. of fat is handled in
both cases.

The overrun from each of the four grades of milk can
be calculated for butter containing a certain per cent, of
fat. Assuming the fat content of butter to be 83 per cent,
on the average (213), the quantity of butter obtained
from the 100 Ibs. of fat, or rather from the portion
thereof which is available for butter, in each case will
be as follows:

Butter cont.

Available fat. 83 pr. ct. fat .

100 Ibs. of fat from 4000 Ibs. of 2.5 pr.ct. milk, 92.0 Ibs. = 110.8 Ibs.
100 " " "• 2857 " 3.5 " " 94.2 " =113.5 "
100 " " " 2500 " 4.0 " " 95.0 " =114.5 "
100 " " " 1666 u 6.0 " u 96.7 " =116.5 "

The overrun in each case will be:

For 2.5 per cent. milk=110.8— 100=10.8 per cent.
11 3.5 " " =113.5-100=13.5 "

" 4.0 " " =114.5-100=14,5 "

" 6.0 " " =116.5-100=16.5 "

All butter makers should obtain more butter from a
certain quantity of milk than the Babcock test shows it
to contain butter fat, but it is impossible to know exactly,
except by chemical analyses, how much butter fat is lost

Calculation of Batter- and Cheese Yield. 183

in the skim milk and the butter milk, and how much
water, salt and curd the butter will contain.

217. Calculation of overrun. The overrun is calculated
by subtracting the amount of butter fat contained in a
certain quantity of milk, from the amount of butter made
from it, and finding the per cent, which this difference is
of the amount of butter fat in the milk.

Example: 8000 Ibs, of milk is received at the creamery on a
certain day; the average test of the milk is 3.8 per cent. ; 340 Ibs.
of butter was made from this milk, as shown by the weights of
the packed tubs. By a simple multiplication we find that the
milk contained 8000X. 038=304 Ibs. of butter fat. The difference
between the weight of butter and butter fat is, therefore, 36 Ibs. ;
36 is ^^ -=11.8 per cent, of the quantity of butter fat in the
milk; that is, the overrun for the day considered was 11.8 per
cent.

The formula for the overrun is as follows:
y._(b-f) 100

x_ -j-

b and / designating the quantities of butter and butter
fat, respectively, made from or contained in a certain
quantity of milk. In the preceding example, the calcu-
lation would be as follows: (840~^4) 10° = 11.8 per cent.

In gathered -cream factories the overrun will naturally
come higher than in separator creameries, since no loss
of butter fat in the skim milk occurs in the former. The
overrun based on the amount of fat in the cream will not
under average creamery conditions be likely to vary
much from 18 per cent.

218. Conversion factor for butter fat. A committee of
the Association of American Agricultural Colleges and
Experiment Stations at the ninth annual convention of

184 Testing Milk and Its Products.

the Association reported that "in the ninety-day Colum-
bian Dairy Test, 96.67 per cent, of the fat in the whole
milk was recovered in the butter. This butter on the
average contained 82.37 per cent, butter fat; in other
words, 117.3 pounds of butter were made from each 100
pounds of butter fat in the whole milk.1 The exact con-
version factor would be 1.173. As this is an awkward
number to use, and as 1^ is so nearly the same ... it
has seemed best to recommend that the latter be used as
the conversion factor.7'

A resolution was adopted by this association recom-
mending that the approximate equivalent of butter be
computed by multiplying the amount of butter fat by 1£.

These figures are the result of more than ordinary care
in skimming, churning and testing, and probably repre-
sent the minimum losses of fat in the manufacturing pro-
cesses. The increase of churn over test represented by
one-sixth, or 16 per cent., may therefore be taken as a
maximum " overrun" under ordinary factory conditions.
Butter makers who report overruns of 16-20 per cent, do
not show their expertness in butter making by such high
figures, but their lack of accuracy in testing, or careless-
ness in working the butter; a large overrun may be ob-
tained both by reading the test too low, and by leaving
an excess of water in the butter, through insufficient
working or other causes.

219. Butter yield from milk of different richness, a. Use
of butter chart. The approximate yield of butter from
milk of different richness is shown in table XI in the

i When 82.37 Ibs. of butter fat will make 100 Ibs. of butter, how much
butter will 96.67 Ibs. of butter fat make ? 82.37 : 96.67 : : 100 : x, x=117.3.

Calculation of Suiter- and Cheese Yield. 185

Appendix. This table is founded on ordinary creamery
experience and will be found to conie near to actual
every- day conditions of creameries where modern meth-
ods are followed in the handling of the milk and its pro-
ducts. The table has been prepared in the following
manner:

It is assumed that the average loss of fat iu the skim milk is
.20 percent., aud that 85 Ibs. of skim milk is obtained from
each 100 Ibs. of whole milk; to this loss of fat is added that from
the butter milk; about 10 Ibs. of butter milk is obtained per 100
Ibs. of whole milk, testing on the average .30 per cent.

If/ designate the fat in 100 Ibs. of milk, then the fat recov-
ered in the butter from 100 Ibs. of milk will be

There is, on the other hand, an increase in weight in the
butter made, owing to the admixture of non-fatty components
therein, principally water and salt. Butter packed and ready
for the market will contain in the neighborhood of 84 per cent.
of fat (213), so that the fat recovered in the butter must be in-
creased by 'gQ4Q=1.19. If B therefore designate the yield of but
ter from 100 Ibs. of milk, the following formula will express the
relation between yield and fat content, provided there are no
other factors entering into the problem, viz. :

B=(f— .20) 1.19

Certain mechanical losses are, however, unavoidable in the
creamery, as in all other factory operations, viz., jnilk and
cream remaining in vats and separators, butter sticking to the
walls of the churn, etc. These losses have been found to aver-
age about 3 per cent, of the total fat in the milk handled, under
normal conditions and under good management (218); we
therefore deduct this amount from the preceding value for B,

and have:

B=(f— .20) 1.16

220. Table XI in the Appendix, founded on this form-
ula, may be used to determine the number of pounds of

186 Testing Milk and Its Products.

butter which milk containing 3 to 5.3 per cent, fat will
be likely to make. It presupposes good and careful work
at the separator, churn and butter worker, and under such
conditions will generally show yields of butter varying
but little from those actually obtained. It may be con-
veniently used by the butter maker or the manager to
check the work in the creamery; the average test of the
milk received during a certain period is found by divid-
ing the total butter fat received, by the total milk, and
multiplying the quotient by 100; the amount of butter
which the total milk of this average fat content will
make, according to the table, is then compared with the
actual churn yield.

Example: A creamery receives 200,000 Ibs. of milk during
a month; the milk of each patron is tested and the fat con-
tained therein calculated. The sum of these amounts of fat
may be 7583 Ibs.; the average test of the milk is then 3.79
per cent. According to table XI, 10,000 Ibs. of milk, testing 3.8,
will make 418 Ibs. of butter, and 200, 000 Ibs., therefore, 8360 Ibs.
of butter. The total quantity of butter made during the month
will not vary appreciably from this figure if the work in the
creamery has been properly done.

221. b. Use of overrun table. The table referred to
above gives a definite calculated butter yield for each
grade of milk, according to average creamery conditions.
As it may be found that this table will give uniformly
either too low or too high results, table XII in Appen-
dix is included, by means of which the butter yield cor-
responding to overruns from 10-20 per cent, may be
ascertained in a similar way as above described.

The total yield of butter is divided by the total num-
ber of pounds of fat delivered; the quotient will give the

Calculation of Butter- and Cheese Yield. 187

amount of butter made from one pound of fat, and this
figure multiplied by the fat delivered by each patron
shows the pounds of butter to be credited to each patron.
To use the table, find in the upper horizontal line the
number corresponding most nearly to the number of
pounds of butter from one pound of fat. The vertical
column in which this falls gives the pounds of butter
from 100 Ibs. of milk containing the per cents, of fat
given in the outside columns (Babcock1).

B. — CALCULATION OF YIELD or CHEESE.

222. a. From fat. The approximate yield of green
cheddar cheese from 100 Ibs. of milk may be found by
multiplying the per cent, of fat in the milk by 2.7; if/
designate the per cent, of fat in the milk, the formula
will, therefore, be:

Yield of cheese =2.7 f. (I)

The factor 2.7 will only hold good as the average of a
large number of cases. In extensive investigations dur-
ing three consecutive years, Van Slyke2 found that
the number of pounds of green cheese obtained for
each pound of fat in the milk varied from 2.51 to
3.06, the average figures for the three years 1892-' 94,
incl., being 2.73, 2.71, and 2.72 Ibs. respectively. The
richer kinds of milk will produce cheese richer in fat,
and will yield a relatively larger quantity of cheese,
pound for pound, than poor milk, for the reason that an
increase in the fat content of milk is accompanied by an

1 Woll, Handbook for Farmers and Dairymen, p. 307.

2 N. Y. experiment station (Geneva), bulletins No. 65 and 82.

188 Testing Milk and Its Products.

increase in the other cheese-producing solids of the milk.1
The preceding formula would not, therefore, be correct
for small lots of either rich or poor milk, but only for
milk of average composition, and for large quantities of
normal factory milk. For cured cheese the factor will
be somewhat lower, viz., about 2.6, on the average.

223. b. From solids not fat and fat. If the percentages
of solids not fat and of fat in the milk are known, the
following formula by Babcock will give close results:

Yield of green cheese = 1. 58 (y +.91 f) . . (II)
s being the per cent, of solids not fat in the milk, and /
the per cent, of fat.2

The solids not fat can be readily ascertained from the
lactometer reading and the per cent, of fat, as shown on
p. 100, by means of table VI in the Appendix.

Table XIII in the Appendix gives the yield of cheese
from 100 Ibs. of milk containing from 2.5 to 6.0 per cent,
fat, the lactometer readings of which range between 26
and 36. By means of this table cheese makers can cal-
culate very closely the yields of cheese which certain
quantities of milk will make: as it takes into considera-
tion the non-fatty solids as well as the fat of the milk,
the results obtained by the uee of this formula will be
more correct than those found by means of formula (I).
The uncertain element in the formula lies in the factor

i Investigations as to the relation between the quality of the milk and
the yield of cheese have been conducted by a number of experiment sta-
tions; the following references give the main contributions published on
this point: N. Y. (Geneva) exp. sta., reports 10-13, incl.; Wis. exp. sta.,
reports 11 and 12; Ont. Agr. College, reports 1891-'96, incl.; Minn. exp. sta.
reports 1892-'9i, incl.; Iowa exp. sta , bull. 21.

2 For derivation of this formula, see Wisconsin experiment station,
twelfth report, p. 105.

Calculation of Butter- and Cheese Yield. 189

1.58, which, as shown above, is based on an average water
content of 37 per cent, in the green cheese. This may,
however, be changed to suit any particular case, e. g., 35
per cent (V/=-54), 40 per cent. (W = 1-67)> etc- The
average percentages of water in green cheese found by
Van Slyke in his investigations referred to above, were
for the years 1892-' 94, respectively, 36.41, 37.05 and 36.70
per cent.

224. c. From casein and fat. If the percentages of
casein and fat in the milk are known, the yield of cheese
may be calculated by the following formula, also pre-
pared by Dr. Babcock:

Yield of cheese = l.l f+2.5 casein . . . (III).
This formula will give fairly correct results, but no
more so than formula (II); it is wholly empirical.

CHAPTEE XIII.
CALCULATING DIVIDENDS.

A.— CALCULATING DIVIDENDS AT CREAMERIES.

225. The simplest method of calculating dividends at
creameries is to find the number of pounds of butter fat
delivered to the creamery by each patron for a certain
length of time, and then multiply this number by the
price per pound of fat. Farmers are usually paid once
a month for their milk at the factory. Each lot of milk
is weighed when delivered at the creamery, and a small
quantity thereof is saved for the composite sample, as
previously explained under Composite tests (176).
Some creameries test these samples at the end of each
week, and others after collecting them for ten days or
two weeks. If the four weekly composite samples of a
patron's milk tested 3.8, 4.0, 3.9, 4.1 per cent., these
four tests are added together, and the sum divided by 4;
the result, 3.95 per cent., is used as the average test of
this milk. By multiplying the total number of pounds
of milk delivered by this patron, by his average test, the
total weight in pounds of butter fat delivered to the fac-
tory during the month is obtained. This weight of fat is
then multiplied by the price to be paid by the creamery
per pound of butter fat 5 the product shows the amount
of money due this patron for the milk delivered during
the time samples were taken.

226. Price per pound of butter fat. The method of ob
taining the price to be paid for one pound of butter fat

Calculating Dividends. 191

varies somewhat in different creameries, on account of
the different ways of paying for the cost of manufacturing
the butter. The method to be followed is generally deter-
mined by agreement between the manufacturer and the
milk producers, in case of proprietary creameries, or be-
tween the shareholders, in co-operative creameries. The
following methods of paying for the cost of manufacture
are at the present time met with in American creameries.

227. I. Proprietary creameries. First. — When the
creamery is owned by some one person or company, the
owner or owners agree to make the butter for 3 or 4 cents
a pound; the difference between the total receipts of the
factory and the amount due the owner is then divided
between the different parties, according to the amount of
butter fat contained in the milk which they delivered.

In the majority of cases, the price charged for making
butter is now 4 cents a pound; 3f and 3J cents are some-
times charged. The larger the amount of milk received
at a factory, the lower will naturally be the cost of man-
ufacturing the butter. l

Second. — The proprietor of the creamery sometimes
agrees to pay a certain price for 100 Ibs. of milk deliv-
ered, according to its fat content, the price of milk con-
taining 4 per cent, of butter fat being the standard. This
price may change during the different seasons of the year
by mutual agreement.

Third. — A creamery owner may offer to pay 1 to 2
cents, usually 1^ cents, below the average market price of
butter, for each pound of butter fat received in the milk.

228. II. Co-operative creameries. In this case, where
the creamery is owned by the patrons, one of the stock -

1 Wisconsin experiment station, bull. 56, p. 26.

192 Testing Milk and Its Products.

holders who is elected secretary attends to the details of
running the factory and selling the product. His ac-
counts show the amount of money received each month
for the butter and other products sold, and the expenses
of running the factory during this time. The expenses
are substracted from the receipts, and the balance is
divided among the patrons, each one receiving his pro-
portionate share according to the amounts of butter fat
delivered in each case (as shown by the total weight and
the average test of milk delivered during this time).

In nearly all cases, the farmers receive about eighty
pounds of skim milk for each hundred pounds of whole
milk they deliver to the factory, in addition to the
amount received for the milk, calculated according to
one or the other of the preceding methods.

229. Illustrations of calculations of dividends. In order
to illustrate the details of calculating dividends, or the
amount to be paid each patron for the milk supplied
each month, when payments are made by each of the
four systems given, it will be assumed that a creamery
receives 5000 pounds of milk daily for thirty days, and
makes 6650 Ibs. of butter from the 150,000 Ibs. of milk
received during this time. The average test of this milk
may be found by multiplying the total weight of milk
delivered by each patron by his average test, and divid-
ing the sum of these products by the total weight of milk
received at the creamery (in the example given, by 150,-
000), the quotient being multiplied by 100. Such calcu-
lations may show that, e. g., 5700 Ibs. of butter fat have
been received in all in the milk delivered by the differ-
ent patrons; this multiplied by 100 and divided by

Calculating Dividends.

193

150,000 gives 3.8 as the average test, or the average
amount of butter fat in each 100 Ibs. of milk received
during the month.

So far, the method of calculation is common for all dif-
ferent systems of payment given above ; the manner of
procedure now differs according to the agreement made
between owner and patrons, or between the shareholders,
in case of co-operative creameries.

230. I. First. — If the net returns for the 6650 Ibs. of
butter sold during the month were $1197, and the creamery
is to receive 4 cents per pound of butter as the cost of
manufacture, etc., the amount due the creamery is
6650 X. 04 -$266, and the patrons would receive $1197—
$266 =$931. This sum, $931, is to be paid to the patrons
for the 5700 Ibs. of butter fat, which, as shown above,
was the weight of fat contained in the 150,000 Ibs. of
milk delivered during the month. The price of one
pound of butter fat is then easily found: $931-^5700 =
16J cents. This price is paid to all patrons for each
pound of butter fat delivered in their milk during the
month. The monthly milk record of three patrons may,
e. g., be as given in the following table:

First week.

Second week

Third week

Fourth week

f.

Patrons

Total
Milk

Is

Milk
Ibs.

Test
pr.ct.

Milk
Ibs.

Test
per ct.

Milk
Ibs.

Test
pr.ct.

Milk
Ibs.

Test
per ct.

Ibs.

P

No. 1

3500

3.6

3000

3.5

3600

3.65

3450

3.45

13,550

3.55

" 2

700

3.8

665

3.8

720

3.6

750

3.7

2,825

3.73

" 3

2480

4.2

2000

3.8

1850

4.0

1500

3.6

7,830

3.90

Multiplying each patron's total milk by his average
test gives the number of pounds of butter fat in his milk,

13

194

Testing Milk and Its Products.

and this figure multiplied by .16J shows the money due
for his milk, as given below:

Patron.

Total milk
Ibs.

Average test
per cent.

Butter fat,
Ibs.

Price of fat
per lb., cents.

Amounts
due.

No. 1

13,550

3.55

481.0

16X

$78.56

No. 2 .

2,825

3.7

104.5

17 06

No 3

7 830

39

3054

Ifiv

48 96

231. Second. — When the proprietor of a creamery agrees
to pay a certain price for 100 Ibs. of 4 per cent. -milk, the
receipts for butter sold and the price per pound of butter
do not enter into the calculation of the amount due each
patron for his milk; but the weight and the test of each
patron's milk are just as important as before. If it is
agreed to pay 66 cents per 100 Ibs. of 4 per cent, -milk
(i. e., milk containing 4 per cent, of butter fat), the price
of one pound of butter fat will be 66-f-4=16J cents, and
the amount due each patron is found by multiplying the
total weight of butter fat in his milk by this price. To
facilitate this calculation, so-called Relative- Value Tables
have been constructed, the use of which is explained
below (237).

232. Third. — If a creamery agrees to pay for butter fat,
say 1 \ cents per pound below the average market price
of butter each month, the price of one pound of butter
fat is found by averaging the market quotations and sub-
tracting 1 \ cents therefrom. If the four weekly market
prices were 17J, 17, 16J and 19 cents, the average of these
would be 17^ cents, and this less 1J gives 16 cents as the
price per pound of fat to be paid to the patrons; this
price is then used in calculating the dividends as in case
of first method (230).

Calculating Dividends.

195

Patron.

Total milk
Ibs.

Average test
per cent.

Butter fat,
Ibs.

Price of fat
per lb., cents.

Amounts
due.

No. 1 ..

13,550
2,825
7,830

3.55
8.7
3.9

481.0
104.5
305.4

16
16
16

$76.96
16.72

48.86

No. 2
No. 3

233. II. If the creamery is owned by the farmers, the
running expenses for a month are subtracted from the
gross returns received for the butter, and the price to be
paid per pound of butter fat is found by dividing the
amount left, by the total number of pounds of butter fat
delivered during the month. This price is used for pay-
ing each patron for his milk according to the amount of
fat contained therein, as already explained under Pro-
prietary Creameries (230).

The monthly running expenses of a co-operative cream-
ery generally include such items as the wages of the
butter maker (and manager or secretary, if these officers
are salaried), labor (hauling, helper, etc. ), cost of butter
packages, coal or wood, salt and other supplies, freight
and commission on the butter sold, repairs and insurance
on buildings, etc. A certain amount is also paid into a
sinking fund (say 5 cents .per 100 Ibs. of milk), which
represents the depreciation of the property, wear and
tear of building and machinery, bad debts, etc. These
items are added together, and their sum subtracted from
the gross receipts for the butter sold during the month.

234. Assuming the receipts for the butter during the
month to be $1197, and the running expenses of the fac-
tory $285, the amount to be divided among the patrons is
$912; the quantity of butter fat received was 5700 Ibs.,

196 Testing Milk and Its Products.

and the price per pound of butter fat will therefore be 16
cents. The account will then stand as given in (232).

235. Other systems of payment. Besides these four
systems of payment, there are various other agreements
made between manufacturer and producer, but with
them all the one important computation is the price to
be paid per pound of butter fat; this forms the basis of
calculating the factory dividends, when milk is paid for
by the Babcock test.

236. Paying for butter delivered. In some instances
patrons desire to receive pay for the quantity of butter
which the milk delivered by them will make. This can
be ascertained quite accurately from the total receipts
and the total weights of both butter fat and butter. The
total money to be paid for butter (the net receipts) are
divided by the number of pounds of butter sold, to get
the price to be paid per pound of butter; the total yield
of butter divided by the total amount of butter fat
delivered in the milk, gives the amount of butter corre-
sponding to one pound of butter fat, and the pounds of
fat delivered by each patron is then multiplied by this
figure. This method requires more figuring than those
given in the preceding, and the dividends are no more
accurate, in fact less so, than when calculations are based
on the price per pound of fat.

237. Relative-value tables. These tables give many of
the multiplications used in computing the amount due
for various weights of milk testing from 3 to 6 per cent,
of fat. They can be easily constructed by any one as
soon as the price of one pound of fat is determined in
each case. If the price to be paid per pound of fat is,

Calculating Dividends. 197

say 15 cents, the value of each 100 Ibs. of milk of differ-
ent quality is found by multiplying its test by 15. If the
average tests of the different patrons' milk vary from 3
to 5 per cent., the relative- value table would be as
follows:

3.0Xl5=45c. per 100 Ibs.

3.1Xl5=46.5c. "

3.2xl5=48c. "

3.3Xl5=49.5c. "

3.4xl5=51c. "

3.5xl5=52.5c. "

3.6Xl5=54c. per 100 Ibs.
3.7Xl5=55.5c. "
3.8Xl5=57c. "

3.9X15-58.5C. u
4.0Xl5=60c. "

etc.

By continuing this multiplication, or adding the mul-
tiplier each time for each tenth of a per cent, up to 5 per
cent, of fat, a table is made that can be used for calcu-
lating the amount due per 100 Ibs. of milk, at this price
per pound, and the weight of milk delivered by each
patron is multiplied by the price per 100 Ibs. of milk
shown in the table opposite the figure representing his test.

Example: A patron supplies 2470 Ibs. of milk, testing 3.2
per cent, of fat; price per pound of fat, 15 cents; he should then
receive 24.70X.48=$11.85 (see above table). Another patron
delivering 3850 Ibs. of milk testing 3.8 per cent, will receive, at
the same price per pound of fat, 38.50X.57=$21.94.

The relative value tables in the Appendix give the
price per 100 Ibs. of milk testing between 3 and 6 per
cent, fat, when the price of three per cent, milk varies
from 30 to 90c. per 100 Ibs. In using the tables, first
find the figure showing the price which it has been de-
termined to pay for 100 Ibs. of milk of a certain quality,
say 3 or 4 per cent. -milk; the figures in the same vertical
column then give the price to be paid per 100 Ibs. of
milk testing between 3 and 6 per cent.

198

Testing Milk and Its Products.

Example 1: It has been decided to pay 90 cents per 100 Ibs.
of 4 per cent. -milk. The figure 90 is then sought in the table in
the same line as 4.0 per cent., and the vertical column in which
it is found gives the price per 100 Ibs. of 3 to 6 per cent.-milk.
3.8 per cent.-milk is thus worth 85 cents per 100 Ibs. and 4.2 per
cent.-milk, $1.01, under the conditions given. The prices of
milk of other qualities are found in the same way.

Example 2: In the example referred to under Illustrations
of calculating creamery dividends (I b, 231), the figures for the
patrons No. 1, 2 and 3, would be as follows:

Patron.

Milk delivered,
Ibs.

Average
test.

Price per 100 Ibs.
of milk, cents.

Amounts
due.

No. 1 ...

" 2

13550

2825

355
37

585
61 0

$7926
1723

" 3

7830

39

64.0

50 11

238. Milk and cream dividends. When cream from farm
hand separators or other sources is brought to a factory
receiving and skimming whole milk, the cream patron's
dividend should be calculated a little differently than
that of the milk patron.

In one case the dividend is based on the weight and the
test of cream and in the other on the weight and the test
of milk; the difference between the two being represented
by the fat left in the factory skim milk. This skim milk
fat is included in the milk patron's dividend and conse-
quently ought also to be allowed for in calculating the
amount due the cream patron. Such an allowance can
be very fairly made by multiplying the cream fat by 1.03.
This is assuming that the one-tenth or more of fat re-
turned to the milk patron in his skim milk is about
three per cent, of the total fat in his whole milk.

Both milk and cream patron suffer the same manufac-
turing loss in the factory butter milk so that an equaliza-

Calculating Dividends. 199

tion of the skimming losses is all that is necessary to put
both on a uniform basis for calculating dividends.

239. The following illustration may help to make these
calculations clearer. Milk patron No. 1 may deliver to
the creamery during the month 5320 Ibs. of milk testing

(coorv V" Q ft \
1(X) '-j

202 Ibs. butter fat. If the price paid the patrons is 20c
then the 202 Ibs.x20c amounts to $40.40 the money due
this patron for his milk. If however another patron
sent 485 Ibs. of cream testing 22.0 per cent, fat to the
same factory during the month the weight of fat in the
cream is first found in the same way as in the milk.

(48^22 ) =106.7 Ibs. butter fat. Now instead of mul-
tiplying this butter fat by 20c as was done for the milk
patron it must first be multiplied by 1.03 which makes
the necessary allowance for the skim milk fat that the
milk patron was paid for. 106.7 X 1.03 =109. 9 Ibs. but-
ter fat which is now multiplied by 20c per pound giving
$21.98. This is the amount due the cream patron when
both milk and cream are received at the same factory
and the cream from both patrons is churned together.1

B. — CALCULATING DIVIDENDS AT CHEESE FACTORIES.

240. The amount of cheese made from a certain quan-
tity of milk depends, as before shown, in a large measure
on the richness of the milk in butter fat (222). Rich
milk will give more cheese per hundredweight than
poor milk, and the increased yields will be nearly, but
not entirely, proportional to the fat contents of the dif-

1 17th Repor t Wis. expt station, p. 90.

200 Testing Milk and Its Products.

ferent kinds of milk. Since the quality of the cheese
produced from rich milk is better than that of cheese
made from thin milk and will demand a higher price, it
follows that no injustice is done by rating the value of
milk for cheese production by its fat content. This sub-
ject has been discussed frequently during late years in
experiment station publications and in the dairy press
(222). Among others, Babcock has shown that the price
of cheese stands in a direct relation to its fat content. *
Prof. Bobertson, the Dairy Commissioner of Canada, is
authority for the statement that the quality of the cheese
made from milk containing 3.0 to 4.0 per cent, of fat was
increased in value by one-eighth of a cent for every two-
tenths of a per cent, of fat in the milk,2 a figure which
is fully corroborated by Dr. Babcock' s results. The
injustice of the "pooling system," by which all kinds of
milk receive the same price, is evident from the preced-
ing; if the milk of a certain patron is richer than that of
others, it will make a higher grade of cheese, and more
of it per hundredweight; hence a higher price should be
paid for it.

Payment on the basis of the fat content of milk is,
therefore, the most equitable method of valuing milk for
cheese making, and in case of patrons of cheese factories
as with creamery patrons, dividends should be calcula-
ted on the basis of the results obtained by testiug the
milk delivered. The testing may be conveniently ar-
ranged by the method of composite sampling, in the way
already described for creameries (176).

1 Wisconsin exp. station, llth report, p. 134.

2 Hoard's Dairyman, March 29, 1895.

Calculating Dividends. 201

241. Calculation of dividends. As with creameries, the
first thing to be ascertained is the price to be paid per
pound of butter fat. The factory records should show
the number of pounds of cheese made from the total milk
delivered to the factory during a certain time, generally
one month, and the money received for this cheese. The
cost of making the cheese and all other expenses that
should be paid for out of the money received for the
cheese, are deducted from the total receipts, and the dif-
ference is divided among the patrons in proportion to
the amounts of butter fat delivered in the milk.

The weights of the milk delivered and the tests of the
composite samples furnish data for calculating the quan-
tities of butter fat to be credited to each patron. The
money to be paid to the patrons is then divided by the
total weight of butter fat delivered to the factory and the
price of one pound of fat thus obtained. The money due
each patron is now found by multiplying the total num-
ber of pounds of butter fat in his milk by this price per
pound.

The illustrations already given for calculating patrons'
dividends at creameries according to the various methods
will serve equally well to show the manner in which div-
idends are calculated at a cheese factory. For the sake of
clearness an example is given that applies directly to
cheese factories.

242. Illustration of calculation of dividends. It may
be assumed that 15,000 Ibs. of green cheese is made
from 150,000 Ibs. of milk delivered to a factory in a
month. According to the weighings and the tests made,
the milk contained 5700 Ibs. of butter fat. If the cheese

202

Testing Milk and Its Products.

sold at an average price of 7 J cents a pound, the gross
receipts would be $1,125.00. The amount to be deducted
from the gross receipts will depend on the agreement
made between the factory operator and the patrons, in
case of proprietary cheese factories, or between the
shareholders and the maker, when the factory is run on
the co-operative plan. As before we shall consider these
systems separately.

243. I. Proprietary cheese factories. The owner of the
factory generally agrees to make the cheese for a certain
price per pound and to pay the patrons what is left after
deducting this amount. If the price agreed on is 1J
cents per pound of green cheese, this would amount to
$225 in the example given. Subtracting this sum from
the gross receipts, $1,125, leaves $900, which is to be
paid the patrons. The total amount of butter fat deliv-
ered by the patrons was 5700 Ibs. ; hence the price of one
pound of butter fat will be 900 -^-5700 = .157 7, or 15.8
cents. Taking the figures for the three patrons already
mentioned under Creamery Dividends, we then have:

Patron

Total milk,
Ibs.

Average
test,
per cent.

Butter fat,
Ibs.

Price
per Ib.
of fat,
cents.

Amounts
due.

No. 1

13,550

3.55

481.0

15.8

$76.00

No. 2

2,825

3.7

104.5

15.8

16.51

No. 3

7,830

3.9

305.4

15.8

48.25

244. Co-operative cheese factories. The method of
payment at co-operative cheese factories is nearly the
same as that already given, except that a certain sum
representing the expenses is subtracted from the gross
receipts for the cheese, and the balance is divided among

Calculating Dividends.

the patrons according to the amounts of butter fat fur-
nished by each, in the same manner as in the above case,
after the price of a pound of fat has been obtained.

The price per 100 Ibs. of milk can be calculated in the
same way as at creameries, by multiplying the test of
each lot by the price per pound of fat. *

i Suggestions regarding the organization of co-operative creameries
and cheese factories will be found in the Appendix, following Table XV.
Draft of constitution and by-laws for co-operative factory associations are
also given in the Appendix. It is hoped that these will prove helpful to
farmers who are about to form such associations.

CHAPTER XIV.
CHEniCAL ANALYSIS OP fllLK AND ITS PRODUCTS

245. An outline of the methods followed in determin-
ing quantitatively the main components of milk and its
products is given in the following for the guidance of
more advanced dairy students. This work cannot be
done outside of a fairly well-equipped chemical labora-
tory, or by persons who have not been accustomed to
handling delicate chemical apparatus and glassware,
analytical balances, etc., and who have not a knowledge
of at least the elements of chemistry and chemical

reactions.

A. — MILK.

246. In a complete milk analysis, the specific gravity
of the milk is determined, and the following milk com-
ponents: water, fat, casein and albumen, milk sugar,
and ash. The methods of analysis described in the fol-
lowing are those used in the chemical laboratory of the
Wisconsin experiment station, which in the main are the
same as those adopted by the Association of Official
Agricultural Chemists, and with but slight modifications,
in general use in the chemical laboratories of all Ameri-
can experiment stations and agricultural colleges.1

247. a. Specific gravity is determined by means of a
picnometer or specific-gravity bottle, since more accurate

1 The methods of analysis adopted by the Association of Official Agri-
cultural Chemists are published annually by the Chemical Division of the
U. S. Department of Agriculture; see Bull, No. 46, revised edition, p 54.

Chemical Analysis of Milk and its Products. 205

results will thus be reached than by using an ordinary
Queveime lactometer. A thermometer is ground into
the neck of the specific-gravity bottle so as to form a
stopper, and the bottle is provided with a glass stoppered
side-tube, to furnish an exit for liquids on expanding.
A specific-gravity bottle holding 100 grams of water is
preferably used. The empty and scrupulously cleaned
bottle is first weighed on a chemical balance. The bot-
tle is then filled with recently-boiled distilled water of a
temperature below 60° F. (15.5° C.); the thermometer
is inserted, and the bottle is warmed slightly by immers-
ing it for a moment in tepid water and left standing until
the thermometer shows 60° F. ; the opening of the side
tube is then wiped off and closed with the stopper, and
the water on the outsi'de of the bottle and in the groove
between its neck and the thermometer is wiped off with
filter paper or a clean handkerchief, when the bottle is
again weighed. The weight being recorded, the bottle is
emptied and dried in a water oven, or if sufficient milk
is at hand, the bottle is repeatedly rinsed with the milk,
the specific gravity of which is to be determined. It is
then filled with milk in a similar manner as in case of
water; the temperature of the milk should be slightly
below 60° F. and is slowly brought up to this degree
after the bottle has been filled, proceeding in the same
way as before with water; the weight of the bottle and
milk is then taken.

The weights of water and of milk contained in the
specific-gravity bottle are found by subtracting the
weight of the empty bottle from the second and the third
weights, respectively, and the specific gravity of the milk

206 Testing Milk and Its Products.

then found by dividing the weight of the milk by that of
the water.

Example: Weight of sp. gr. bottle-}- water... 146.91 13 grams.
Weight of sp. gr. bottle empty 46.9423 "

Weight of water .............. 99.9690 grams.

Weightofsp.gr. bottle+milk ..... 149.8708 grams.

Weight of sp. gr. bottle empty ..... 46.9423 "

Weight of milk ........... ,...102.9285 grams.

1O9

Sp.gr. of milk=--=1.0296

248. If a plain picnometer without a thermometer attached,
is available, the method of procedure is similar to that described,
with the difference that the temperature of the water and of
the milk must be brought to 60° F. before the picnometer is
filled, or the picnometer filled with either liquid is placed in
water in a small beaker, which is very slowly warmed to 60° F.
and kept at this temperature for some time so as to allow the
liquid in the picnometer to reach the temerature desired; the
temperature of the water in the beaker is ascertained by means
of an accurate chemical thermometer. The perforated stopper
is then wiped off, the picnometer is taken out of the water,
wiped and weighed. It is necessary to weigh very quickly if
the room temperature is much above 60° F., as in such cases the
expanding liquid will flow on to the balance pan, with a re-
sultant loss in weight from evaporation.

The weights of specific-gravity bottle or picnometer, empty
and filled with water, need only be determined a couple of
times, and the averages of these weighings are used in subse-
quent determinations.

249. Westphal balance. Where only a small amount
of milk is available, or in rapid work, the specific grav-
ity may be taken with considerable accuracy by means
of a Westphal balance. The arrangement and use of

Chemical Analysis of Milk and its Products. 207

this convenient little apparatus is readily explained
verbally.

For the determination of the specific gravity of loppered
milk, see 260.

250. b. Water. The milk is weighed into a perforated
copper tube filled with prepared dry asbestos. The tubes
are made from perforated sheet copper, with holes about
.7 mm. in diameter and about .7 mm. apart; they are
60 mm. long, 20 mm. in diameter and closed at the bot-
tom. The asbestos is prepared from clean fibrous asbes-
tos, which is ignited at low heat in a muffle oven, treated
with a little dilute HC1 (1 : 3) and then with distilled
water till all acid is washed out; it is then torn in loose
layers and dried at a low temperature in an air bath;
when dry it can be easily shredded in fine strings and is
placed in a wide-mouth, glass-stoppered bottle.

About two grams of asbestos are placed in each tube,
packing it rather loosely; the tube is then weighed, a
small narrow beaker being inverted over it on the scale
pan. 5 cc. of milk are now dropped on to the asbestos
from a 5 cc. fixed pipette, the beaker again placed over
the tube, and the weight of the 5 cc. of milk delivered
-f-copper tube taken. The weight of the milk is ob-
tained by difference. The tubes are then placed in a
steam oven and heated at 100° C. until they no longer
decrease in weight, which ordinarily will take about
three hours. Place in desiccator until cold, and weigh ;
the difference between the weight of the tube+milk and
this last weight gives the water contained in the milk,
which is then calculated in per cent, of the quantity of
milk weighed out.

208 Testing Milk and Its Products.

Example: Weight of tube+beaker-f-inilk 29.3004 grams.

Weight of tube-fbeaker 24.1772 "

Milk weighed out 5.1232 grams.

Weight of tube+beaker+milk 29.3004 grams.

Weight of tube-j-beaker-j-milk, dry 24.9257 "

Weight of water 4.3747 grains.

Per cent of water in milk=^^^:=85.39 per cent.

Note. The per cent, of total solids in milk is often given,
instead of that of water; this may be readily obtained by
subtracting the weight of the empty tube from that of
the tube filled with milk solids, and finding the per cent,
of the milk weighed out which this difference makes. In
the above example, the weight of milk solids thus is
24.9257— 24.1772:=. 7485 grams, and the per cent, of
total solids in the milk = 14. 61 per cent.

251. Alternate method. Five cc. of milk are measured out on
a weighed flat porcelain dish (50-60 mm. in diameter; porcelain
crucible covers will answer the purpose better than any other
vessel on the market, provided the handle be broken off or
ground off level on an emery wheel); this is weighed rapidly;
two or three drops of 30 per cent. -acetic acid are added, and the
dish is dried in a steam oven at 100° C. until no further loss in
weight is obtained. After cooling in desiccator, the weight of
the milk solids is obtained, and by calculation as before, the
per cent, of water or total solids in the milk.

252. c. Fat. The dried tubes from the water determi-
nation are placed in Caldwell extractors and connected
with weighed, numbered glass flasks (capacity, 2-3 oz.);
the extractors are attached to upright Liebig condensers
and the tubes extracted with pure ether, free from water,
alcohol or acid, until all fat is dissolved; 4-5 hours' ex-
traction is sufficient; in case of samples of skim milk it

Chemical Analysis of Milk and its Products. 209

is well to continue the extraction for at least 6 hours.
The ether is then distilled off and recovered, and the
flasks dried in a copper oven until constant weight; after
cooling they are weighed, and the amount of fat contained
in the quantity of milk originally weighed into the tubes
is thus ascertained, and the per cent, present in the milk
calculated.
Example: Weight of flask -f fat .................... 15.8039 grams.

Weight of flask ............................. 15.5171 "

Weight of fat ................... 2868 grams.

Milk weighed out ............................................. 5.1232 grams.

Per cent, of fat in milk= '^ =5.60 per cent.

253. d. Casein and albumen. The sum of these compo-
nents is generally determined by the Kjeldahl method.1
5 cc. of milk are measured carefully into a flat-bottom
800 cc. Jena flask, 20 cc. of concentrated sulfuric acid
(C. P. ; sp. gr., 1.84) are added, and .7 gram of mercuric
oxid (or its equivalent in metallic mercury); the mixture
is then heated over direct flame until it is straw-colored
or perfectly white; a few crystals of potassium perman-
ganate are now added till the color of the liquid remains
green. All the nitrogen in the milk has then been con-
verted into the form of ammonium sulfate. After cooling,
200 cc. of ammonia- free distilled water are added, 20 cc.
of a solution of potassium sulfid (containing 40 grams
sulfid per liter), and a fraction of a gram of powdered
zink. A quantity of semi-normal HCl-solution, more
than sufficient to neutralize the ammonia obtained in the
oxidation of the milk, is now carefully measured out
from a delicate burette (divided to ^0 cc.) into an

1 Fresenius' Zeitschrift, 22, p. 366; U. S. Dept. Agr., Chern. Div., bull. 43.
14

210 Testing Milk and Its Products.

Erlenmeyer flask, and the flask connected with a distilla-
tion apparatus. At the other end, the Jena flask con-
taining the watery solution of the ammonium sulfate is
connected, after adding 50 cc. of a concentrated soda
solution (1 pound "pure potash" dissolved in 500 cc. of
distilled water and allowed to settle); the contents of the
Jena flasks are now heated to boiling, and the distillation
is continued for forty minutes to an hour, until all
ammonia has been distilled over.

The excess of acid in the Erlenmeyer receiving-flask
is then accurately titrated back by means of a tenth-
normal standard ammonia-solution, using a cochineal -
solution1 as an indicator. From the amount of acid
used, the per cent, of nitrogen is obtained; and from it,
the per cent, of casein and albumen in the milk by multi-
plying by 6.25.2 The amount of nitrogen contained in
the chemicals used is determined by blank experiments
and deducted from the nitrogen obtained as described.

Example: The weight of 5 cc. of milk (as obtained in deter-
mining the water in the milk) was 5.1465 grams. 5 cc. of stand-
ard HC1 are added to the receiver, and 1.55 cc. of JQ alkali-
solution are used in titrating back the excess of acid. 1.55 cc.

of £ alkali = ^-=.51 cc. ^ acid-solution; the ammonia dis-
tilled over therefore neutralized 5.00 — .51=4.49 cc. acid. By
blank trials it was found that the reagents used furnish an
equivalent of .02 cc. acid in the distillate; this quantity sub-
tracted from the acid-equivalent of the nitrogen of the milk
leaves 4.47 cc. 1 cc. semi-normal HCl-solution corresponds to

7 milligrams or .007 grams of nitrogen; 4.47 cc. —• HC1 therefore

iSutton, Volumetric Analysis, 4th edition, p. 31.

2 The factor 6.30 or 6.37 is more correct for the albuminoids of milk, but
has not yet been generally adopted, (p. 15, foot note).

Chemical Analysis of Milk and its Products. 211

represents .03129 grams of nitrogen. This quantity of nitrogen
was obtained from the 5.1465 grams of milk measured out; the

milk therefore contains ^^~°=.608 per cent, of nitrogen,
and .608X6.25=3.80 per cent, of casein and albumen.

254. Casein and albumen may be determined separately
by Van Slyke's method:1 10 grams of milk are weighed
out and diluted with about 90 cc. of water at 40°-42° C.
1.5 cc. of a 10 per cent, acetic-acid solution are then
added; the mixture is well stirred with a glass rod and
the precipitate allowed to settle for 3-5 minutes. The
whey is decanted through a filter and the precipitate
washed two or three times with cold water. The nitro-
gen is determined in the filter paper and its contents by
the Kjeldahl method; blank determinations with the
regular quantities of chemicals and the filter paper used
are made, and the nitrogen found therein deducted.
The per cent, of nitrogen obtained multiplied by 6.25
gives the per cent, of casein in the milk.

255. Albumen is determined in the filtrate from the
casein- precipitate; the filtrate is placed on a water bath
and heated to boiling temperature of water for ten to
fifteen minutes. The washed precipitate is then treated
by the Kjeldahl method for the determination of nitro-
gen; the amount of nitrogen multiplied by 6.25 gives the
amount of albumen in the milk. The difference between
the total nitrogenous components found by the Kjeldahl
method, and the sum of the casein and the albumen, as
given above, is due to the presence in milk of a third
class of nitrogen compounds. (18).

1 Bulletin No, 43, p. 189, Chemical Division, U. S. Dept. of Agriculture.

212 Testing Milk and Its Products.

256. e. Milk sugar is generally determined by differ-
ence, the sum of fat, casein and albumen, (total N X 6.25),
and ash, being subtracted from the total solids. It may
be determined directly by means of a polariscope, or
gravimetrically by Fehling's solution; only the former
method, as worked out by Wiley, l will be given here.

The specific gravity of the milk is accurately deter-
mined, and the following quantities of milk are measured
out by means of a 100 cc. pipette graduated to .2 cc. (or
a 64 cc. pipette made especially for this purpose, with
marks on the stem between 63.7 and 64.3cc.), according
to the specific gravities given: 1.026, 64.3 cc. ; 1.028,
64.15 cc.; 1.030, 64.0 cc.; 1.032, 63. 9 cc.; 1.034, 63.8 cc,;
1.036, 63.7 cc. These quantities refer to the Schmidt-
Haensch half-shadow polariscopes, standardized for a
normal weight of 26.048 grams of sugar. The milk is
measured into a small flask graduated at 100 cc. and
102.6 cc. ; 30 cc. of mercuric- iodid solution (prepared
from 33.2 grams potassium iodid, 13.5 grams mercuric
chlorid, 20 cc. glacial acetic acid and 640 cc. water) are
added; the flask is filled to 102.6 cc. mark with distilled
water, the contents mixed, filtered through a dry filter,
and when the filtrate is perfectly clear, the solution is
polarized in a 200 millimeter tube. The reading of the
scale divided by 2, shows the per cent, of lactose (milk
sugar) in the milk. Take five readings of two different
portions of the filtrate, and average the results.

257. f. Ash. About 20 cc. of milk are measured into
a flat-bottom porcelain dish and weighed; about one- half
of a cc. of 30 per cent. -acetic acid is added, and the milk

1 Agricultural Analysis, iii, p. 275; Am. Chem. Jour., 6, p. 289 et. seq.

Chemical Analysis of Milk and its Products. 213

first dried on water bath and then ignited in a muffle oven

at a low red heat. Direct heat should not be applied in

determining the ash of milk, since alkali chlorids are

likely to be lost at the temperature to which milk solids

have to be heated to ignite all organic carbon.

Example: Weight of porcelain dish+milk ..... 49.0907 grams.

Weight of porcelain dish ............... 28.3538 grams.

Weight of milk .............. 20.7369 grams.

Weight of dish +milk,after ignition 28.5037 grams.
Weight of dish ................. ! ............. 28.3538 grams.

Weight of milk ash ......... 1499

.1499X100
Per cent, of ash = =.72 per cent.

The residue from the determination of solids (251)
may also be used for the ash determination.

258. Acidity of milk. The acidity of milk is conven-
iently determined by means of Farrington's alkaline
tablets (seep. 120), or by one-tenth normal soda solu-
tion. In the latter case, 20 cc. of milk are measured into
a porcelain casserole; a few drops of an alcoholic phe-
nolphtalein solution are added, and soda solution is drop-
ped in slowly from a burette until the color of the milk
remains uniformly pinkish on agitation. 1 cc. of N alkali
corresponds to .009 grams lactic acid, or to .045 per cent.,
when 20 cc. of milk are taken (see p. 112).

B. — CREAM, SKIM MILK, BUTTERMILK, WHEY, CON-
DENSED MILK.

259. The analysis of these products is conducted in
the same manner as in case of whole milk, and the same
constituents are determined, when a complete analysis is
wanted. Skim milk, butter milk, and whey generally

214 Testing Milk and Its Products.

contain only small quantities of solids, and especially of
fat, and it is, therefore, well to weigh out a larger quan-
tity than in case of whole milk; if possible, toward 10
grams. The acidity of sour milk and butter milk must be
neutralized with sodium carbonate previous to the dry-
ing and extraction, as lactic acid is soluble in ether and
would thus tend to increase the ether-extract (fat), if not
combined with an alkali previous to the extraction.

260. Specific gravity of butter milk. The specific grav-
ity of butter milk (as well as of sour or loppered milk)
is determined by Weibull's method; a known volume
of the milk is mixed with a certain amount (say 10
per cent. ) of ammonia of a definite specific gravity, and
the specific gravity of the liquid determined after thorough
mixing and subsequent standing for an hour. If A desig-
nate the volume of butter milk taken, B that of ammo-
nia, and C that of the mixture; and if furthermore s de-
signate the specific gravity of the butter milk^ that of
the ammonia, and s2 that of the mixture, we have

_Cs!i-B81
A

Klein1 has modified this method by weighing the
liquids, thus securing greater accuracy; 22 to 24 per cent. -
ammonia is used, one- tenth as much being taken as the
amount of milk weighed out. The results come uniformly
.0005 too high, and this correction should always be made.
The following formula will give the specific gravity of the
milk, which in case of careful work will be accurate to
one-half lactometer degree; if the letters given above
designate weights (instead of volume as before) and

specific gravities of the liquids, respectively, we have

A

s=-

C B

i Milchzeitung, 1896, p. 656.

Chemical Analysis of Milk and its Products. 215

261. Condensed milk. The same methods are, in gen-
eral, followed in the analysis of condensed milk as with
whole milk. Condensed milk is preferably diluted with
three times its weight of water prior to the analysis, both
because such a solution can be more easily handled
than the undiluted thick condensed milk, and the errors
of analysis are thereby reduced, and because the fat is
not readily extracted except when the milk has been
diluted. The same constituents are determined as in
case of whole milk, viz., solids, fat, casein and albumen,
ash, milk sugar, and cane sugar (if any has been added
to the milk). The milk sugar is determined by differ-
ence; if the student has a knowledge of the manipula-
tion of the polariscope and has had experience in gravi-
metric sugar analysis, the milk sugar is determined
gravimetrically, and the cane sugar by the difference
between the polariscope reading after inversion and the
milk sugar present.

The specific gravity of condensed milk may be determined
by a method similar to that of McGill. 1 50 gr. of the
thoroughly mixed sample are weighed into a tared beaker
and washed with warm water into a 250 cc. flask, cooled
to 60°, filled to the mark and carefully mixed. The
specific gravity of this solution (a) is then taken and the
original density is calculated by means of the following
formula:

Sp. gr. of condensed milk= ^\^

Concentration. The extent of concentration of con-
densed milk may be determined approximately by the
formula devised by McGill (loc. cit.):

i Bulletin 54, Laboratory, Inland Rev. Dept., Ottawa, Canada.

216 Testing Milk and Its Products.

Concentration (c)=^j-

where a and s designate the solids not fat and specific
gravity, respectively of the condensed milk, and al and
sl the corresponding data for the milk used. If s1 =1.030
and a1 —9 per cent., then c = <^ gives the concentration.

C. — BUTTER.

262. Sampling. A four- to eight-ounce sample of but-
ter is melted in a tightly- closed pint fruit jar, shaken
vigorously and cooled until the butter is hardened, the
jar being shaken vigorously at short intervals during the
cooling so as to keep the water of the butter evenly dis-
tributed in the mass.

263. a. Determination of water. Small pieces of but-
ter (about 2 grams in all) are taken from the sample by
means of a steel spatula and placed in glass tubes, seven-
eighths of an inch in diameter and two and a half inches
long, closed at the bottom by a layer of stringy asbestos,
and filled two- thirds full of asbestos prepared as for milk
analysis (250). The tubes are dried at 100° C. in a water
oven, until no further loss in weight takes place, and are
then cooled and weighed. The loss in weight shows the
per cent, of water present.

264. b. Fat. The tubes are placed in CaldwelPs ex-
tractors and extracted for four hours with anhydrous
ether; the ether is then distilled off, and the flasks dried
in the steam bath and weighed, the increase in weight
giving the fat in the samples of butter weighed out.

265. c. Casein. 10 grams of butter are weighed into
a small beaker provided with a lip, and treated twice
with about 50 cc. of gasoline each time; the solution is

Chemical Analysis of Milk and its Products. 217

filtered off, and the residue transferred to a filter and
dried; its nitrogen content is then determined by the
Kjeldahl method (253). The nitrogen in the filter and
the chemicals used is determined by blank trials and de-
ducted. The nitrogen multiplied by 6.25 gives the
casein in the butter.

266. d. Ash. 1. 10 grams of butter are weighed into
a porcelain dish and treated twice with gasoline, as in the
preceding determination; the solution is filtered through
an ash-free (quantitative) filter, and the filter when dry
is transferred to the dish. The dish is heated in an air-
bath for half an hour and then placed in a muffle oven,
where the contents are burnt to a light greyish ash; the
dish is now cooled in a desiccator and weighed. The
difference between this weight and that of the empty dish
gives the amount of ash in the butter weighed out.

267. 2. About two grams of butter are weighed into a
small porcelain dish, half filled with stringy asbestos; the
dish is dried for an hour in the water oven, and the fat
then set fire to with a match, the asbestos fiber serving
as a wick. When the flame has gone out, the dish is
placed in a muffle oven, and the residue burnt to a grey-
ish ash. After cooling, the dish is weighed, and the per
cent, of ash in the butter calculated as under method 1.

268. Complete analysis of butter in the same sample.
About 2 grams of the butter are weighed into a platinum
gooch half filled with stringy asbestos, and dried in a water
oven at 100° C. to constant weight, cooled and weighed.
The difference gives water in the sample. The gooch is
then treated repeatedly with small portions of gasoline,
suction being applied, and again dried in the water oven,

218 Testing Milk and Its Products.

cooled, and weighed; the fat in the sample is obtained
from the difference between this and the preceding
weight. The gooch is then carefully heated over direct
flame until a light greyish ash is obtained; this operation
is preferably done in a muffle oven to avoid possible loss
of alkali chlorids. The loss in weight gives the casein in
the sample weighed out, and the increase in the weight
of the gooch over that of the empty gooch with asbestos,
gives the ash (mainly salt) of the butter. The salt in the
ash may be dissolved out by hot water, and the chlorin
content of the solution determined by means of a stand-
ard silver- nitrate solution, using potassium chromate as
an indicator.

269. A practical method of estimating the salt content
of butter. A method of estimating the salt content of
butter, which is applicable also outside of chemical lab-
oratories, has been worked out jointly by Messrs. Alfred
Vivian and C. L. Fitch.1 The salt of the butter is dis-
solved in hot water, and a certain portion of the solution
when cool is pipetted off and titrated with a silver-nitrate
solution prepared by dissolving one silver- nitrate tablet
in 50 cc. water, potassium chromate being used as an
indicator. The silver nitrate tablets are sold for 60 cents
per 100, which number is sufficient to make 100-150
tests. The method is advertised in the dairy press under
the name of " Fitch's Salt Analysis." Directions for
making tests by this method are furnished with the ap-
paratus when this is bought. The price of a complete
outfit is $4.50.

1 Wis. Experiment Station, XVII Report, pp. 98-101; Hoard's Dairy-
man, February 15, 1901, article: "Uniform Salting of Butter."

Chemical Analysis of Milk and its Products. 219

DETECTION OF ARTIFICIAL BUTTER.

270. Determination of the specific gravity of the fil-
tered butter fat serves as a good preliminary test. A

Apparatus used in "Fitch's Salt Analysis."

number of practical methods for the detection of artifi-
cial butter have been proposed, but they are either worth-
less, in case of samples containing a considerable propor-

220 Testing Milk and Its Products.

tion of natural butter, or give satisfactory results only in
the hands of experts. The Reichert-Wollny method
given in detail below is the standard method the world
over, and the results obtained by it are accepted in the
courts.

271. Filtering the butter fat. The butter to be exam-
ined is placed in a small narrow beaker and kept at 60°
C. for about two hours. The clear supernatant fat is
then filtered through absorbent cotton into a 200 cc. Erlen-
meyer flask, taking care that none of the milky lower
portion of the contents of the beaker be poured on the
filter. In sampling the butter fat, it is poured back and
forth repeatedly from a small warm beaker into the
flask, and the quantity wanted is then drawn off with a
warm pipette.

272. Specific gravity. This is generally determined at
100° C. The method of procedure is similar to that de-
scribed under milk (248). The picnometer (capacity
about 25 cc. ) is filled with dry filtered butter fat, free
from air bubbles; the fat is heated for 30 minutes in a
beaker, the water in which is kept boiling. On cooling,
the weight of picnometer and fat is obtained, and by cal-
culation as usual, the specific gravity of the fat.

The specific gravity of pure natural butter fat at 100° C.
ranges between .8650 and .8685, while artificial butter fat
(i. e., fat from other sources than cows' milk) has a spe-
cific gravity at 100° C. of below .8610, and generally
about .85.

273. Reichert-Wollny method (Volatile Acids). 5.75 cc.
of fat are measured into a strong 250 cc. weighed saponi-
fication flask, by means of a pipette marked to deliver

Chemical Analysis of Milk and its Products. 221

this amount, and the flask when cool is weighed again.
10 cc. of 95 per cent, -alcohol and 2 cc. of a concentrated
soda solution (1:1) are then added to the flask which is
securely stoppered with a cork stopper tied down with a
piece of twine. The flask is heated for an hour on the
water bath, being gently rotated from time to time in
order to facilitate the saponification. The flask is then
uncorked, the alcohol evaporated slowly and the heating
continued until the last traces of alcohol are gone.

100 cc. of recently boiled distilled water are now added,
and the flask heated on the water bath until the soap
formed is completely dissolved. When cooled to about
70° C., 40 cc. of dilute sulfuric acid (25 cc. cone. H2SO4
per liter) are added to the soap solution to decompose
the soap into free fatty acids and glycerol. The flask is
restoppered and heated until the insoluble fatty acids
separated out form a clear oily layer on the surface of
the acid solution in the flask. After cooling to room
temperature, a few pieces of pumice stone (prepared by
throwing the pieces at a white heat into distilled water
and keeping them under water until used) are added,
the flask connected with a glass condenser, heated slowly
till boiling begins, and the contents then distilled at such
a rate as will bring 110 cc. of the distillate over in as
nearly thirty minutes as possible.

The distillate is mixed thoroughly and filtered through
a dry filter; 100 cc. of the filtrate are poured into a 250 cc.
beaker and titrated with a deci-normal barium -hydrate
solution, half a cubic centimeter of phenolphtalein solu-
tion being used as an indicator. A blank test is made
in the same manner as described, and the amount of

222 Testing Milk and Its Products.

alkali solution used deducted from the results obtained
with the samples analyzed. The number of cubic centi-
meters of barium-hydrate solution used is increased by
one-tenth, and the so-called Reichert number thus obtained.
The Eeichert number for pure butter fat will ordinar-
ily come above 24 cc. ; butter fat from stripper cows will
have a low Reichert number. Pure olemargarine will have
a Eeichert number of 1-2 cc. ; and mixtures of artificial
and natural butters will give intermediate numbers.

274. Renovated or process butter. For detection and
examination of renovated or ' 'process' ' butter, see Coch-
ran Journ. Frankl. Inst., 1899, p. 94; Analyst, 1899, p. 88.

D. — CHEESE.
For method of sampling, see p. 89.

275. a. Water. Five grams of cheese cut into very
thin slices are weighed into a small porcelain dish filled
about one-third full with freshly-ignited stringy asbestos;
the dish is placed in a water oven and heated for ten
hours. The loss in weight is taken to represent water.

276. b. Fat. About 5 grams of cheese are ground
finely in a small porcelain mortar with about twice its
weight of anhydrous copper sulfate, until the mixture is
of a uniform light blue color and the cheese evenly dis-
tributed throughout the mass. The mixture is transferred
to a glass tube of the kind used in butter analysis (263),
only a larger size; a little copper sulfate is placed at the
bottom of the tube, then the mixture containing the
cheese, and on top of it a little extracted absorbent cotton
or ignited, stringy asbestos; the tube is placed in an
extraction apparatus and extracted with anhydrous ether

Chemical Analysis of Milk and its Products. 223

for fifteen hours. The ether is then distilled off, the
flasks dried in a water oven at 100° C. to constant weight,
cooled and weighed. The method is apt to give too low
results and, therefore, not to be preferred to the Babcock
test for cheese (102).

277. c. Casein (total nitrogen X 6. 25). About 2 grams
of cheese are weighed out on a watch glass and trans-
ferred to a Jena nitrogen flask, and the nitrogen in the
sample determined according to the Kjeldahl method
(253); the percentage of nitrogen multiplied by 6.25
gives the total nitrogenous components of the cheese.

278. d. Ash. The residue from the water determina-
tion is taken for the ash; it is preferably set fire to, in
the same manner as explained under determination of
ash in butter (267), before it is placed in the muffle oven
and incinerated. The increase in the weight above that
of the empty dish -(-asbestos, gives the amount of ash in
the sample weighed out.

279. e. Other constituents. The sum of the percent-
ages of water, fat, casein and ash, subtracted from 100,
will give the per cent, of other constituents, organic
acids, milk sugar, etc., in the cheese.

DETECTION OF OLEOMARGARINE CHEESE ("FILLED"
CHEESE).

280. About 25 grams of finely-divided cheese are
extracted with ether in a Caldwell extractor or a paper
extraction cartridge; the ether is distilled off, and the
fat dried in the water oven until there is no further loss
in weight. 5. 75 cc. of the clear fat are then measured
into a 250 cc. saponification flask and treated according

224 Testing Milk and Its Products.

to the Beichert-Wollny method, as already explained
under Detection of Artificial Butter (270). 1

TESTS FOR ADULTERATION or MILK AND CREAM.

281. The nitric acid test may prove useful as corrobora-
tive evidence that a sample of milk has been watered
(123). Normal fresh milk does not contain nitrates,
while common well-water, particularly on farms where
precautions to guard against contamination of the
water supply have not been taken, in general contains
appreciable amounts of nitrates, nitrites and ammonia
compounds, and watered milk will, therefore, in such cases
also contain nitrates.2 The method for detection of
small amounts of nitrates in milk, as given by Eich-
mond3 is as follows: Place a small quantity of diphenyl-
amin at the bottom of a porcelain dish, and add to it
about 1 cc. of pure H2SO4 (cone.); allow a few drops of
the milk serum (obtained by adding a little acetic acid
to the milk and warming) to flow down the sides of the
dish and over the surface of the acid. If a blue color
developes in the course of ten minutes, though it may
be faint, it shows the presence of nitrates, after ten
minutes a reddish-brown color is always developed from
the action of the acid on the serum. There should be
no difficulty in detecting an addition of 10 per ct. of
water to the milk by this test, if the water added con-
tained 5 parts of nitric acid, or more, per 100,000.

Besides by the methods given in the preceeding (pp.
101-107), watering or skimming of milk may be detected

1 See Arb. Kais. Ges.-Amt., 14, 506-598.

2 Uffelmann, Deutsche Vierteljahresschr. f. off. Ges.-pfl. 15, p. 663.

3 The Analyst, 1893, p. 272.

Chemical Analysis of Milk and its Products. 225

by determing the specific gravity of a, the skim milk,
£>, the milk serum, and c, the whey.

282. a. Specific gravity of skim milk. The milk is set
in a flat porcelain or glass dish for 12-24 hours in a cold
room; the layer of cream formed is then skimmed off,
and the sp. gr. of the skim milk determined at 60° F.
Skim milk has a sp. gr. of .002 to .0035 (2 to 3.5 lacto-
meter degrees) above that of the corresponding whole
milk; a smaller difference than this indicates that the
milk was skimmed. If both skimming and watering had
been practiced, the difference given above might be ob-
tained, but the analysis of the milk would in such case
easily disclose the adulteration.

283. b. Specific gravity of the milk serum. To 100 cc.
milk 2 cc. of 20 per ct. -acetic acid are added, and the
mixture heated in a covered beaker or closed flask for
5-10 min. on a water-bath at 55-65° C. After cooling,
the milk serum is filtered off and its sp. gr. determined
at 60° F. In case of pure milks, the sp. gr. of the milk
serum (at 60°) will come above 1.0270. Serum from
normal milks contain 6.3 to 7.5 per ct. solids and .22
to .28 per ct. fat; by the addition of 10 per ct. of water,
the solids in the serum are lowered .3 to .5 per ct., and
the sp. gr., .0005.1

c. Specific gravity of whey. 500 cc. of milk are warmed
in water of 40-50° C. until its temperature is 35° C.;
one-half cc. of rennet extract (12-15 drops) is added,
and the milk stirred thoroughly. After allowing the
curd to solidify for 10 minutes, it is cut and the whey
filtered off through several layers of cheese cloth. The

iKonig, Menschl. Nahrungsmittel II, p. 276.
15

226 Testing Milk and Its Products.

whey must be clear; it is cooled to 15° C. and its sp. gr.
determined. The sp. gr. of whey from normal milk ob-
tained in the manner given will range between 1.027
and 1.031. A sp. gr. of 1.026 or below indicates water-
ing. An addition of 4 per ct. of water lowers the sp. gr.
of the whey about 1 lactometer degree.1

284. Detection of coloring matter. Milk which has
been watered or skimmed, or both, is sometimes further
adulterated by unscrupulous milk peddlers through the
addition of a small quantity of cheese color; this will
mix thoroughly with the milk, and, if added judiciously,
will impart a rich cream color to it. The presence of
foreign coloring matter in milk is easily shown by shak-
ing 10 cc. of the milk with an equal quantity of ether;
on standing, a clear ether solution will rise to the surface;
if artificial coloring matter has been added to the milk,
the solution will be yellow colored, the intensity of the
color indicating the quantity added; natural fresh milk
will give a colorless ether solution.

A method given by Wallace 2 is claimed to detect one
part of coloring matter in 100,000 of milk.

Inorganic coloring matter like chromates and bi-
chromates have, although fortunately rarely, been used
to impart a rich color to adulterated milk or poor cream.
Chromates may be detected by the reddish yellow color
produced when a little 2 per cent. -silver nitrate solution
is added to a few cubic centimeters of the milk.

285. Detection of pasteurized milk or cream. Prof.
Storch, of Copenhagen, Denmark,3 in 1898 published a

i Siats, Unters. landw. wicht. Stoffe, p. 88.
•2N. J. Dairy Commissioner, report, 1896, p. 36.
340th report, Copenhagen experiment station.

Chemical Analysis of Milk and its Products. 227

simple method for ascertaining whether milk, cream,
butter or other dairy products have been heated to at
least 176° F. (80° C.). The test is made as follows: A
teaspoonful of the milk is poured into a test tube, and
1 drop of a weak solution of peroxid of hydrogen (2 per
cent.) and 2 drops of a paraphenylenediarnin-solution
(2 per cent. ) are added. The mixture is then shaken; if a
dark violet color appears at once, the milk has not been
heated, or at any rate not beyond 176° F. If a sample
of butter is to be examined, 25 grams are placed in a
small beaker and melted by being placed in water of
60° C. The clear butter fat is poured off, and the re-
maining liquid is diluted with an equal volume of water.
The mixture thus obtained is examined as in case of milk.

286. Boiled milk. The preceding test will serve to
distinguish between raw and boiled milk, and also to
ascertain if milk has been adulterated with diluted con-
densed milk. To what extent such an adulteration can
be practiced without being detected by this or similar
tests, has not been determined, but if a control test be
made at the same time with a sample of milk of known
purity, a small admixture of boiled (or diluted con-
densed) milk can doubtless be detected.1

287. Gelatine in cream. This method of adulteration
is sometimes practiced in the city cream trade, to impart
stiffness and an appearance of richness to the cream. To
detect the gelatine, a quantity of the suspected cream is
mixed with warm water, and acetic acid is added to
precipitate the casein and fat (1.5 cc. of 10 per cent.-

i See also Siats, Unters. landw. wicht. Stoffe, p. 60, and Molkerei-Ztg.
(Hildesheim), 1899, p. 677.

228 Testing Milk and Its Products.

acetic acid per 10 cc. of cream is sufficient). The pre-
cipitate is filtered off, and a few drops of a strong tannin
solution are added to the clear filtrate. Pure cream will
give a slight precipitate, while in the presence of gela-
tine a copious precipitate will come down.

The picric-acid method has also been proposed for the
detection of small quantities of gelatine in cream.1

288. Starch in Cream. Starch is mentioned in the dairy
literature as an adulterant of milk and cream. It is
doubtful, however, if it is ever used for this purpose at
the present time. In the case of ice-cream, on the other
hand, a small quantity of corn starch is often added to
thicken the milk used. It may in such a case be readily
detected by means of the iodin reaction. A solution of
iodin will produce a deep blue color in the presence of
starch; a small amount of iodin is taken up by the
cream before the blue coloration appears.

289. Microscopic impurities (particles of hay, litter,
woolen or cotton fibres, dung, etc.). These impurities
may be separated by repeated dilution of the milk with
pure distilled water, leaving the mixture undisturbed
for a couple of hours each time before the liquid is
syphoned off. When the milk has been entirely removed
in this manner, the residue is filtered off, dried and
weighed. A quart of milk or cream should not give any
visible sediment on standing for several hours.

DETECTION OF PRESERVATIVES IN DAIRY PRODUCTS.

290. a. Boracic acid (borax, borates, preservaline, etc.).
100 cc. of milk are made alkaline with a soda or potash
solution, and then evaporated to dryness and incinerated.

1 The Analyst, 1897, p. 320.

Chemical Analysis of Milk and its Products. 229

The ash is dissolved in water to which a little hydro-
chloric acid has been added, and the solution filtered.
A strip of tumeric paper moistened with the filtrate will
be colored reddish brown when dried at 100° C. on a
watch glass, if boracic acid is present.

If a little alcohol is poured over the ash to which con-
centrated sulfuric acid has been added, and fire is set to
the alcohol after a little while, it will burn with a yel-
lowish green tint, especially noticeable if the ash is
stirred with a glass rod and when the flame is about to
go out.

291. The following modification of the first test given is said
to show the presence of only a thousandth of a gram of borax
in a drop of milk (about .15 per cent.):1

Place in a porcelain dish one drop of milk with two drops of
strong hydrochloric acid and two drops of saturated tumeric
tincture; dry this on the water bath, cool and add a drop of
ammonia by means of a glass rod. A slaty blue color changing
to green is produced if borax is present.2

292. b. Bi-Carbonate of soda. 100 cc. of milk to which
a few drops of alcohol are added, are evaporated and
carefully incinerated; the proportion of carbonic acid in
the ash as compared with that of milk of known purity
is determined. If an apparatus for the determination of
carbonic acid is available, like the Scheibler apparatus,
etc., the per cent, of carbonic acid per gram of ash (and
quart of milk) can be easily ascertained. Normal milk
ash contains only a small amount of carbonic acid (less
than 2 percent.), presumably formed from the citric acid
of the milk in the process of incineration.

1 N. J. Dairy Commissioner, report 1896, p. 37.

2 See also 139, 144.

230 Testing Milk and Its Products.

The following qualitative test is easily made: To 10 cc.
of milk add 10 cc. of alcohol and a little of a one-per cent,
rosolic-acid solution. Pure milk will give a brownish
yellow color; milk to which soda has been added, a rose
red color. A control experiment with milk of known
purity should be made.

293. c. Fluroids. 100 cc. of milk are evaporated in a
platinum or lead crucible, and incinerated; the ash is
made strongly acid with concentrated sulfuric acid. If
fluorids are present, hydrofluoric acid will be generated
on gentle heating and will be apparent from its etching
a watch glass placed over the crucible.1

294. d. Salicylic acid (salicylates, etc.). 20 cc. of milk
are acidulated with sulfuric acid and shaken with ether;
the ether solution is evaporated, and the residue treated
with alcohol and a little iron-chlorid solution; a deep
violet color will be obtained in the presence of salicylic
acid.

295. e. Formalin, (a forty-per cent, solution of formal-
dehyde in water). A solution of diphenylarnin is made
with water and just enough sulfuric acid to dissolve it.
The milk to be tested, or better, the distillate therefrom,
is added to this solution and boiled. If formalin be pres-
ent, a white flocculent precipitate is formed; if the acid
used contained nitrates, a green precipitate will be
formed.

The following method by Hehner is stated to show the
presence of 1 part of formaldehyde in 200, 000 parts of
milk : the milk is diluted with an equal volume of water,

i Chromates in dairy products may be readily determined by the use of
a silver-nitrate solution, see Molkerei Ztg. (Berlin) 1899, p. 603.

Chemical Analysis of Milk and its Products. 231

and strong H2SO4 (sp. gr. 1.82-1.84) is added. A vio-
let ring is formed at the junction of the two liquids if
formaldehyde is present; if not, a slight greenish tinge
will be seen. The violet color is not obtained with milks
containing over .05 per cent, formaldehyde.1

i Chem. News, 1896, No. 71; Milchzeitung, 1896, 491; 1897, 40, 667; The An-
alyst, 1895, 152, 154, 157; 1896, 285.

APPENDIX.

Table I. Composition of milk and its products.

No. of
analyses.

Water.

Fat.

Casein
and
alb'men

Milk
sugar.

Ash.

Authority.

Cows' milk

793

pr. ct.

87.17
87.75
87.40
86.48
87.1
74.57
68.82
73.90
90.43
90.52
90.60
90.12
91.67
93.38
93.12

58.99

25.61
13.59
12.93
13.08
13.73
11.57

10.23
36.33
38.00
36.84
34.38

32.06
39.79
46.00
50.5

pr. ct.
3.69

3.40
3.75
4.20
4.1

3.59
22.66
17.60
.87
.32
.31
1.09
.27
.32
.27

12.42

10.35
84.39
84.53

84.26
84.82
84.70

85.74
40.71
30.25
33.83
32.71

34.43
23.92
11.65
1.2

pr. ct.

3.55
3.50
3.10
3.511

pr. ct.
4.88

4.60
5.10

"•.71

.75
.65

2.71

Konig.8
Fleischmann.

U (1

li «

900
2173
120,540
42
43
203
56
354
7
57
31
46

Van Slyke.
Holland.6
Vieth.
Konig.8

u

Holland.6
Konig.8
Holland.6
Konig.8

«

Holland.6
Konig.8
Van Slyke.

Konig.8

u

II

((

(( U

tl 11

Colostrum milk

17. 643
3.76

2.67
4.23

1.56
.53
.62
.70

Cream ..

Cream Cooley

Skim milk (gravity)

<( U 11

Skim milk (centrifugal)
Butter milk

3.26

4.74

3.06
4.03

5.29
4.04

.74

.72

it n

Whey...,

.86

.81

11.92

11.79
.74
.61
.81
1.1
A

A

18.84
25.35
23.72
26.38

28.00
29.67
34.06
43.1

4.79
5.

14.49

50.06
4.62
.68
.66
3
)5

)8
1.02
1.43
5.
2.95

5.
1.79
3.42

.65

80

2.18

2.19
.66
1.25
1.19
.09
2.78

3.05
3.10
4.97
61
3.58

51
4.73

4.87
5.2

u*

Condensed milk,
(no sugar added)
Condensed milk,
(sugar added)

36

64
302
10
11
78
350

9
127
143

Butter

" sweet cream

" sour cream

" unsalted

" World's Fair
u American pre-
mium

Farrington.

Morrow.
Konig.8

Van Slyke.
Drew.

Shutt.
Koni-

Storch.

Cheese cream

u full cream

" cheddar green.

" cheddar, cured ...
" World's Fair
mammoth
" half-skim

27

1
21
41

" skim

11 centrifugal skim.

1 Forty-two analyses.

2 Eight analyses.
313.60 percent, albumen.

4 .12 percent, lactic acid.
6 Mostly European samples.
6 Massachusetts' samples.

234

Testing Milk and Its Products.

I,

^ i

i •

1

j

W

ft

f Q *

ji

S

Q

^3 -2

•— • ^

H

tj

eoi

2M b

! §

2 -^

K

O

I:

ill

! !i

J« *

5

:a *

; i\

300 »-l
c5 9
ft

"*.

£t

a3 «

y II

t

BUTTER.

1

|

sl!

8

X

kC

.fe

m

X

"to

.

TB

•i

+£

o

•^ ' ^ -^l

1

•

§

g*

^

CD

"E

Si

"5 *

o

CO CO ^,5

o

o^

^

oa Oi ag

"O

0>S

HCO

5

02 -H*

1

-g

lO Wt> t^ 'O

•t

*

s*

CO COCOCOCOCOCO CO

coco

1

S

M

M

Solids
not fat.

Per ct.

UD i — ii — ICO i — i i — i
QO^.^OSOS^ "^

5S

1

i-< ga

"S

(—1 r— HO 1C jj§5

, o

.

o§

5^

^' S 2 *3 2 S £-i ^ 2

co ^i <ri ci i-i

|

H8

:

i — ' i — i ac-I
cj

£

M

e I

"3 3 ^

S >-7

1

4

C

a

I .s jti ii
1 ||

i|l

S^» OJ 0> -g

"M .. ft ft (53

n s -j «>

Appendix.

*H*

235

^ H O O 00 15

3^3 *

livalent of 12 pe

f fl
°<S*

Iture.
intity the eqi

o o|«

CO ^'3^

.of Agricu
LI be in quc

iroducts.

0Q Cl eo* ^ *O OQ i-H

, U.S.Dept
I milk sha
ill be fat.
for dairy p

C5J3 to

O iO 00 O O t» 'O

faff

co^g^co <M'CO o

o co co co c^ cc *^ c^i co

•d'So'jj

**g as*

i — i i — i to C

a "a.10.0* a

• " ' ' ^^ ' '. ut) C^l • •
0 C»O5 C5

f|»S

<Ti 00 O>

: o : : coos

Is «

(M Q d)

.C^S ^

0000000 r— 0 ^ 10

||-gj

(N (N **g£ (M "^ C<1 (M r-

<N CO* <M' (^j (M* (M* (N* • CO ^g G<l

. ^"S^S

S1 • "-1 u

QQr-l 1 1

i ^ a^^"

Qsrf^

oJ

il U |
1i 11 ^

i 1 iSiil

i i i i i :| ! •§ 1 i^I
S i | I i^«5 PH |1|

Illlllj 8 ilS

I fl?l|g|3^ sj|w?

A .SWpqQflO^QQ T3^-^^
3 fl4*-1 ^^3 15 eg o3

i ss; ill l|

i State standards fro
2 In New York and (
k solids in crude mi
States not named ha

2^ ^3 § o» ^
O fi, «^> £

5 gg S^ fi § 1

: ^6 &q ^ o S

i

236 Testing Milk and Its Products.

Table III. Quevenne lactometer degrees corresponding to
N. Y. Board of Health degrees. (See p. 97. )

Bd. of Health
degrees.

Quevenne
scale.

Bd. of Health
degrees.

Quevenne
scale.

Bd. of Healtl
degrees.

Quevenne
scale.

60

17.4

81

23.5

101

29.3

61

17.7

82

23.8

102

29.6

62

18.0

83

24.1

103

29.9

63

18.3

84

24.4

104

30.2

64

18.6

85

24.6

105

30.5

65

18.8

86

24.9

106

30.7

66

19.1

87

25.2

107

31.0

67

19.4

88

25.5

108

31.3

68

19.7

89

25.8

109

31.6

69

20.0

90

26.1

110

31.9

70

20.3

91

26.4

111

32.2

71

20.6

92

26.7

112

32.5

72

20.9

93

27.0

113

32.8

73

21.2

94

27.3

114

33.1

74

21.5

95

27.6

115

33.4

75

21.7

96

27.8

116

33.6

76

22.0

97

28.1

117

33.9

77

22.3

98

28.4

118

34.2

78

22.6

99

28.7

119

34.5

79

22.9

100

29.0

120

34.8

80

23.2

Table IV. Value of — ^ for sp. gr. from 1.019 to 1.0369.

Sp.gr: (s) =

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.0009

1.019

1.864

1.874

1.884

1.894

1.903

1.913

1.922

1.932

1.941

1.951

1.020

1.961

1.970

1.980

1.990

1.999

2.009

2.018

2.028

2.038

2.047

1.021

2.057

2.066

2.076

2.086

2.095

2.105

2.114

2.124

2.133

2.143

1.022

2.153

2.162

2.172

2.181

2.191

2.200

2.210

2.220

2.229

2.239

1.023

2.249

2.258

2.267

2.277

2.286

2.296

2.306

2.315

2.325

2.334

1.024

2.344

2.353

2.363

2.372

2.382

2.391

2.401

2.410

2.420

2.430

1.025

2.439

2.449

2.458

2.468

2.477

2.487

2.496

2.506

2.515

2.525

1.026

2.534

2.544

2.553

2.563

2.573

2.582

2.591

2.601

2.610

2.620

1.027

2.629

2.638

2.648

2.657

2.667

2.676

2.686

2.695

2.705

2.714

1.028

2.724

2.733

2.743

2.752

2.762

2.771

2.781

2.790

2.799

2.809

1.029

2.818

2.828

2.837

2.847

2.856

2.865

2.875

2.884

2.893

2.903

1.030

2.913

2.922

2.931

2.941

2.951

2.960

2.969

2.979

2.988

2.997

1.031

3.007

3.016

3.026

3.035

3.044

3.054

3.063

3.072

3.082

3.091

1.032

3.101

3.110

3.120

3.129

3.138

3.148

3.157

3.166

3.176

3.185

1.033

3.195

3.204

3.213

3.223

3.232

3.241

3.251

3.260

3.269

3.279

1.034

3.288

3.298

3.307

3.316

3.326

3.335

3.344

3.354

3.363

3.372

1.035

3.382

3.391

3.400

3.410

3.419

3.428

3.438

3.447

3.456

3.466

1.036

3.475

3.484

3.494

3.503

3.512

3.521

3.531

3.540

3.549

3.559

(See directions for use, p. 105).

Appendix. 237

Table V. Correction-table for specific gravity of milk.

1*

Temperature of milk (in degrees Fahrenheit).

1

51

52

53

54

55

56

57

58

59

60

20

19.3

19.4

19.4

19.5

19.6

19.7

19.8

19.9

19.9

20.0

21

20.3

20.3

20.4

20.5

20.6

20.7

20.8

20.9

20.9

21.0

22

21.3

21.3

21.4

21.5

21.6

21.7

21.8

21.9

21.9

22.0

23

22.3

22.3

22.4

22.5

22.6

22.7

22.8

22.8

22.9

23.0

24

23.3

23.3

23.4

23.5

23.6

23.6

23.7

23.8

23.9

24.0

25

24.2

24.3

24.4

24.5

24.6

24.6

24.7

24.8

24.9

25.0

26

25.2

2-5.2

25.3

25.4

25.5

25.6

25.7

25.8

25.9

?G.O

27

26.2

26.2

26.3

26.4

26.5

26.6

26.7

26.8

26.9

27.0

28

27.1

27.2

27.3

27.4

27.5

27.6

27.7

27.8

27.9

28.0

29

28.1

28.2

28.3

28.4

28.5

28.6

28.7

28.8

28.9

29.0

30

29.1

29.1

29.2

29.3

29.4

29.6

29.7

29.8

29.9

30.0

31

30.0

30.1

30.2

30.3

30.4

30.5

30.6

20.8

30.9

31.0

32

31.0

31.1

31.2

31.3

31.4

31.5

31.6

31.7

31.9

32.0

33

31.9

32.0

32.1

32.3

32.4

32.5

32.6

32.7

32.9

33.0

34

32.9

33.0

33.1

33.2

33.3

33.5

33.6

33.7

33.9

34.0

35

33.8

33.9

34.0

34.2

34.3

34.5

34.6

34.7

34.9

35.0

61

62

63

64

65

66

67

68

69

70

20

20.1

20.2

20.2

20.3

20.4

20.5

20.6

20.7

20.9

21.0

21

21.1

21.2

21.3

21.4

21.5

21.6

21.7

21.8

22.0

22.1

22

22.1

22.2

22.3

22.4

22.5

22.6

22.7

22.8

23.0

23.1

23

23.

23.2

23.3

23.4

23.5

23.6

23.7

23.8

24.0

24.1

24

24.

24.2

24.3

24.4

24.5

24.6

24.7

24.9

25.0

25.1

25

25.

25.2

25.3

25.4

25.5

25.6

25.7

25.9

26.0

26.1

26

26.1

26.2

26.3

26.5

26.6

26.7

26.8

27.0

27.1

27.2

27

27.

27.3

27.4

27.5

27.6

27.7

27.8

28.0

28.1

28.2

28

28.

28.3

28.4

28.5

28.6

28.7

28.8

29.0

29.1

29.2

29

29.1

29.3

29.4

29.5

29.6

29.7

29.9

30.1

30.2

30.3

30

30.1

30.3

30.4

30.5

30.7

30.8

30.9

31.1

31.2

31.3

31

31.2

31.3

31.4

31.5

31.7

31.8

31.9

32.1

32.2

32.4

32

32.2

32.3

32.5

32.6

32.7

32.9

33.0

33. £

33.3

33.4

33

33.2

33.3

33.5

33.6

33.8

33.9

34.0

34.2

34.3

34.5

34

34.2

34.3

34.5

34.6

34.8

34.9

35.0

35.2

35.3

35.5

35

35.2

35.3

35.5

35.6

35.8

35.9

36.1

36.2

36.4

36.5

DIRECTIONS.— Bring the temperature of the milk to within 10° of
60° F. Take the reading of the lactometer and that of the temperature of
the milk; find the former in the first vertical column of the table and the
latter in the first horizontal row of figures; the figure where the horizontal
and vertical columns meet is the corrected lactometer reading; e.g., ob-
served, 31.0 at 67° F. ; corrected reading, 31.9.

238

Testing Milk and Its Products.

Table VI. Per cent, of solids not fat, corresponding to 0 to
6 per cent, of fat, and lactometer readings of 26 to

36. (See directions for use, p. 100. )

Vi

O

LACTOMETER READINGS AT 60° F.

tf •

IS

§3

26

27

28

29

30

31

32

33

34

35

36

1

0

6.50

6.75

7.00

7.25

7.50

7.75

8.00

8.25

8.50

8.75

9.00

0

0.1

6.52

6.77

7.02

7.27

7.52

;.77

8.02

8.27

8.52

8.77

9.02

0.1

0.2

6.54

6.79

7.04

7.29

7.54

7.79

8.04

8.29

8.54

8.79

9.04

0.2

0.3

6.56

6.81

7.06

7.31

7.56

7.81

8.06

8.31

8.56

8.81

9.06

0.3

0.4

6.58

6.83

7.08

7.33

7.58

7.83

8.08

8.33

8.58

8.83

9.08

0.4

0.5

6.60

6.85

7.10

7.35

7.60

7.85

8.10

8.35

8.60

8.85

9.10

0.5

0.6

6.62

6.87

7.12

7,37

7.62

7.87

8.12

8.37

8.62

8.87

9.12

0.6

0.7

6.64

6.89

7.14

7.39

7.64

7.89

8.14

8.39

8.64

8.89

9.14

0.7

0.8

6.66

6.91

7.16

7.41

7.66

7.91

8.16

8.41

8.66

8.91

9.16

0.8

0.9

6.68

6.93

7.18

7.43

7.68

7.93

8.18

8.43

8.68

8.93

9.18

0.9

1.0

6.70

6.95

7.20

7.45

7.70

7.95

8.20

8.45

8.70

8.95

9.20

1.0

1.1

6.72

6.97

7.22

7.47

7.72

7.97

8.22

8.47

8.72

8.97

9.22

.1

1.2

H.74

6.99

7.24

7.49

7.74

7.99

8.24

8.49

8.74

8.99

9.24

.2

1.3

6.76

7.01

7.26

7.51

7.76

8.01

8.26

8.51

8.76

9.01

9.26

.3

1.4

6.78

7.03

7.28

7.53

7.78

8.03

8.28

8.53

8.78

9.03

9.28

.4

1.5

6.80

7.05

7.30

7.55

7.80

8.05

8.30

8.55

8.80

9.05

9.30

.5

1 6

6 8ft

7 07

7 3ft

7 57

7 8ft

8 07

8 3ft

8 57

8 8?

9 07

9 3ft

C

1.7

6.84

7.09

7.34

7.59

7.84

8.09

8.34

8.59

8.84

9.09

9.34

.7

1.8

6.86

7.11

7.36

7.61

7.86

8.11

8.36

8.61

8.86

9.11

9.37

.8

1.9

6.88

7.13

7.38

7.63

7.88

8.13

8.38

8.63

8.88

9.13

9.39

.9

2.0

6.90

7.15

7.40

7.65

7.90

8.15

8.40

8.C6

8.91

9.16

9.41

2.0

2.1

6.92

7.17

7.42

7.67

7.92

8.17

8.42

8.68

8.93

9.18

9.43

2.1

2.2

6.94

7.19

7.44

7.69

7.94

8.19

8.44

8.70

8.95

9.20

9.45

2.2

2.3

6.96

7.21

7.46

7.71

7.96

8.21

8.46

8.72

8.97

9.22

9.47

2.3

2.4

6.98

7.23

7.48

7.73

7.98

8.23

8.48

8.74

8.99

9.24

9.49

2.4

2.5

7.00

7.25

7.50

7.75

8.00

8.25

8.50

8.76

9.01

9.26

9.51

2.5

2.6

7.02

7.27

7.52

7.77

8.02

8.27

8.52

8.78

9.03

9.28

9.53

2.6

2.7

7.04

7.29

7.54

7.79

8.04

8.29

8.54

8.80

9.05

9.30

9.55

2.7

2.8

7.06

7.31

7.56

7.81

8.06

8.31

8.57

8.82

9.07

9.32

9.57

2.8

2.9

7.08

7.33

7.58

7.83

8.08

8.33

8.59

8.84

9.09

9.34

9.59

2.9

Appendix. 239

Table VI. Per cent, of solids not fat (Continued).

LACTOMETER READINGS AT 60° F.

«!

u

u

&

26

27

28

29

30

31

32

33

34

35

36

$*

3.0

7.10

7.35

7.60

7.85

8.10

8.36

8.61

8.86

9.11

9.36

9.61

3.0

3.1

7.12

7.37

7.62

7.87

8.13

8.38

8.63

8.88

9.13

9.38

9.64

3.1

3.2

7.14

7.39

7.64

7.89

8.15

8.40

8.65

8.90

9.15

9.41

9.66

3.2

3.3

7.16

7.41

7.66

7.92

8.17

8.42

8.67

8.92

9.18

9.43

9.68

3.3

3.4

7.18

7.43

7.69

7.94

8.19

8.44

8.69

8.94

9.20

9.45

9.70

3.4

3.5

7.20

7.45

7.71

7.96

8.21

8.46

8.71

8.96

9.22

9.47

9.72

3.5

3.6

7.22

7.48

7.73

7.98

8.23

8.48

8.73

8.98

9.24

9.49

9.74

3.6

3.7

7.24

7.50

7.75

8.00

8.25

8.50

8.75

9.00

9.26

9.51

9.76

3.7

3.8

7.26

7.52

7.77

8.02

8.27

8.52

8.7.7

9.02

9.28

9.53

9.78

3.8

3.9

7.28

7.54

7.79

8.04

8.29

8.54

8.79

9.04

9.30

9.55

9.80

3.9

4.0

7.30

7.56

7.81

8.06

8.31

8.56

8.81

9.06

9.32

9.57

9.83

4.0

4.1

7.32

7.58

7.83

8.08

8.33

8.58

8.83

9.08

9.34

9.59

9.85

4.1

4.2

7.34

7.60

7.85

8.10

8.35

8.60

8.85

9.11

9.36

9.62

9.87

4.2

4 3

7 36

7 6?

7 87

8 12

8 37

8 6?

8 88

9 13

9 38

9 64

9 89

4.3

4.4

7.38

7.64

7.89

8.14

8.39

8.64

8.90

9.15

9.40

9.66

9.91

4.4

4.5

7.40

7.66

7.91

8.16

8.41

8.66

8.92

9.17

9.42

9.G8

9.93

4.5

4.6

7.43

7.68

7.93

8.18

8.43

8.68

8.94

9.19

9.44

9.70

9.95

4.6

4.7

7.45

7.70

7.95

8.20

8.45

8.70

8.96

9.21

9.46

9.72

9.97

4.7

4.8

7.47

7.72

7.97

8.22

8.47

8.72

8.98

9.23

9.48

9.74

9.99

4.8

4.9

7.49

7.74

7.99

8.24

8.49

8.74

9.00

9.25

9.50

9.76

10.01

4.9

5.0

7.51

7.76

8.01

8.26

8.51

8.76

9.02

9.27

9.52

9.78

10.03

5.0

5 1

7 53

7 78

8 03

8 28

8 53

8 79

9 04

9 29

9 54

9 80

10 05

5 1

5.2

7.55

7.80

8.05

8.30

8.55

8.81

9.06

9.31

9.56

9.82

10.07

5.2

5.3

7.57

7.82

8.07

8.32

8.57

8.83

9.08

9.33

9.58

9.84

10.09

5.3

5.4

7.59

7.84

8.09

8.34

8.60

8.85

9.10

9.36

9.61

9.86

10.11

5.4

5.5

7.61

7.86

8.11

8.36

8.62

8.87

9.12

9.38

9.63

9.88

10.13

5.5

5.6

7.63

7.88

3.13

8.39

8.64

8.89

9.15

9.40

9.65

9.90

10.15

5.6

5.7

7.65

7.90

8.15

8.41

8.66

8.91

9.17

9.42

9.67

9.92

10.17

5.7

5.8

7.67

7.92

8.17

8.43

8.68

8.94

9.19

9.44

9.69

9.94

10.19

5.8

5.9

7.69

7.94

8.20

8.45

8.70

8.96

9.21

9.46

9.71

9.96

10.22

5.9

6.0

7.71

7.96

8.22

8.47

8.72

8.98

9.23

9.48

9.73

9.98

10.21

6.0

240 Testing Milk and Its Products.

Directions for Use of Tables VII, VIII, IX, and XI.
TABLES VII, and VIII. Find the test of the milk in table VII or
of cream in table VIII; the first or last horizontal row of fig-
ures, the amounts of fat in ten thousand, thousands, hundreds,
tens, and units of pounds of milk are then given in this verti-
cal column. By adding the corresponding figures for any given
quantity of milk or of cream, the total quantity of butter fat
contained therein is obtained.

Example: How many pounds of fat is contained in 8925 Ibs. of milk
testing 3.6-5 per cent.? On p. 242, second column the test 3.65 is found, and
by going downward in this column we have :

8000 Ibs 292. Ibs.

900 Ibs 32.9 Ibs.

20 Ibs 7 Ibs.

6 Ibs 2 Ibs.

8925 Ibs. of milk. 325.8 Ibs. of fat.

8925 IbB. of milk testing 3.65 per cent., therefore, contains 325.8 Ibs. of
butter fat.

TABLE IX. The price per pound is given in the outside vertical
columns, and the weight of butter fat in the upper and lower
horizontal row of figures. The corresponding tens of pounds
are found by moving the decimal point one place to the left,
the units, by moving it two, and the tenths of a pound, by
moving it three places to the left. The use of the table is,
otherwise, as explained above.

Example: How much money is due for 325.8 Ibs. of butter fat at 15%
cents per pound? In the horizontal row of figures beginning with 15% on
p. 217, we find :

800 Ibs $46.50

20 Ibs 3.10

6 Ibs 77

.8 Ibs .12

325.8 Ibs. 850.49

825.8 Ibs. of butter fat at 15% cents per pound, therefore, is worth $50.49.

TABLE XI. Find the test of milk in the upper or lower hori-
zontal row of figures. The amounts of butter likely to be made
from ten thousand, thousands, hundreds, tens, and units of
pounds of milk are then given in this vertical column. The use
of the table is, otherwise, as explained above in case of table VII.

Example: How much butter will 5845 Ibs. of milk testing 3. 8 per cent,
be apt to make under good creamery conditions ? In the column headed
3.8, we find :

5000 Ibs 209.0 Ibs.

800 Ibs 33.4 Ibs.

40 Ibs 1.7 Ibs.

5 Ibs.... .2 Ibs.

5845 Ibs. 244.3 Ibs.

5845 Ibs. of milk testing 3.8 per cent, of fat will make about 244.3 Ibs, of
butter, under conditions similar to those explained on pp. 184-188,

Appendix.

241

Table VII. Pounds of fat in I to 10,000 Ibs. of milk, testing 3.0
to 5.35 per cent. (See directions for use, p. 240.)

-^

a

3.00

3.05

3.10

3.15

3.20

3.25

3.30

3.35

3.40

3.45

3.50

3.55

I

Milk

Milk

Ibs.

Ibs.

10,000

300

305

310

315

320

325

330

335

340

345

350

355

10,000

9,000

270

275

279

284

289

293

297

302

306

311

315

320

9,000

8,000

240

244

248

252

256

260

264

268

272

276

280

284

8,000

7,000

210

214

217

221

224

228

231

235

238

242

245

249

7,000

6,000

ISO

183

186

189

192

195

198

201

204

207

210

213

6,000

5,000

150

153

155

158

160

163

165

168

170

173

175

178

5,000

4,000

120

122

124

126

128

130

132

134

136

138

140

142

4,000

3,000

90.0

91.5

93.0

94.5

96.0

97.5

99.0

101

102

104

105

107

3,000

2,000

60.0

61.0

62.0

63.0

64.0

65.0

66.0

67.0

68.0

69.0

70.0

71.0

2,000

1,000

30.0

30.5

31.0

31.5

32.0

32.5

33.0

33.5

34.0

34.5

35.0

35.5

1,000

900

27.0

27.5

27.9

28.4

28.8

29.3

29.7

30.2

30.6

31.1

31.5

32.0

900

800

24.0

24.4

24.8

25.2

25.7

26.0

26.4

26.8

27.2

27.6

28.0

28.4

800

700

21.0

21.4

21.7

22.1

22.4

22.8

23.1

23.5

23.8

24.2

24.5

24.9

700

600

18.0

18.3

18.6

18.9

19.2

19.5

19.8

20.1

20.4

20.7

21.0

21.3

600

500

15.0

15.3

15.5

15.8

16.0

16.3

16.5

16.8

17.0

17.3

17.5

17.8

500

400

12.0

12.2

12.4

12.6

12.8

13.0

13.2

13.4

13.6

13.8

14.0

14.2

400

300

9 0

q 9

9 8

9 5

9 6

9 8

9 9

10 1

10 9

10 4

10 5

10 7

300

200

6.0

6.1

6.2

6.3

6.4

6.5

6.6

6.7

6.8

6.9

7.0

7.1

200

100

3.0

3.1

3.1

3.2

3.2

3.3

3.3

3.4

3.4

3.5

3.5

3.6

100

90

2.7

2.8

2.8

2.8

2.9

2.9

3.0

3.0

3.1

3.1

3.2

3.2

90

80

2.4

2.4

2.5

2.5

2.6

2.6

2.6

2.7

2.7

2.8

2.8

2.8

80

70

2J

2.1

2.2

2.2

2.2

2.3

2.3

2.3

2.4

2.4

2.5

2.5

70

60

1.8

1.8

1.9

1.9

1.9

2.0

2.0

2.0

2.0

2.1

2.1

2.1

60

50

Af\

1.5

19

1.5

1 9

1.6

19

1.6
i °,

1.6

10

1.6
i °,

1.7

10

1.7

10

1.7

1.7

1.8

1.8

50

Af\

rtU

30

.Z

.9

-L. Z

.9

,£i

.9

J. . O

.9

.0

1.0

j. .0
1.0

.0

1.0

.0

1.0

1.0

1.0

1.1

1.1

4U

30

20

.6

.6

.6

.6

.6

.7

.7

.7

.7

.7

.7

.7

20

10

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.4

.4

10

9

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

9

8

.2

.2

.2

.3

.3

.3

.3

.3

.3

.3

.3

.3

8

7

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

7

6

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

6

5

.2

.2

.2

.2

.2

.2

.2

0

.2

.2

.2

.2

5

4

.1

.1

.1

.1

.1

.1

.1

!i

.1

.1

.1

.1

4

3

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

3

2

.1

.1

.1

.1

.1

1

.1

.1

.1

.1

.1

.1

2

1

1

1

3.05

3.15

3.20

3.40

3.50

T

3.00

3.10

3.25

3.30

3.35

3.45

3.55

It)

242 Testing Milk and Its Products.

Table VH. Pounds of fat in I to 10,000 Ibs. of milk ( Continued}.

2

3.60

3.65

3.70

3.75

3.80

3.85

3.90

3.95

4.00

4.05

4.10

4.15

r

Milk

Milk

Ibs.

Ibs.

10,000

360

365

370

375

380

385

390

395

400

405

410

415

10,000

9,000

324

329

333

338

342

347

351

356

360

365

369

374

9,000

8,000

288

292

296

300

304

308

312

316

320

324

328

332

8,000

7.000

252

256

259

263

266

270

273

277

280

284

287

291

7,000

6,000

216

219

222

225

228

231

234

237

240

243

246

249

6,000

5,000

180

183

185

188

190

193

195

198

200

203

205

208

5,000

4,000

144

146

148

150

152

154

156

158

160

162

164

166

4,000

3,000

108

110

111

113

114

116

117

119

120

122

123

125

3,000

2,000

72.0

73.0

74.0

75.0

76.0

77.0

78.0

79.0

80.0

81.0

82.0

83.0

2,000

1,000

36.0

36.5

37.0

37.5

38.0

38.5

39.0

39.5

40.0

40.5

41.0

41.5

1,000

900

32.4

32.9

33.3

33.8

34.2

34.7

35.1

35.6

36.0

36.5

36.9

37.4

900

800

28.8

29.2

29.6

30.0

30.4

30.8

31.2

31.6

32.0

32.4

32.8

33.2

800

700

25.2

25.6

25.9

26.3

26.6

27.0

27.3

27.7

28.0

28.4

28.7

29.1

700

600

21.6

21.9

22.2

22.5

22.8

23.1

23.4

23.7

24.0

24.3

24.6

24.9

600

500

18.0

18.3

18.5

18.8

19.0

19.3

19.5

19.8

20.0

20.3

20.5

20.8

500

400

14.4

14.6

14.8

15.0

15.2

15.4

15.6

15.8

16.0

16.2

16.4

16.6

400

300

10.8

11.0

11.1

11.3

11.4

11.6

11.7

11.9

12.0

12.2

12.3

12.5

300

200

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

200

100

3.6

3.7

3.7

3.8

3.8

3.9

3.9

4.0

4.0

4.1

4.1

4.2

100

90

3.2

3.3

3.3

3.4 3.4

3.5

3.5

3.6

3.6

3.7

3.7

3.7

90

80

2.9

2.9

3.0

3.0

3.0

3.1

3.1

3.2

3.2

3.2

3.3

3.3

80

70

2.5

2.6

2.6

2.6

2.7

2.7

2.7

2.8

2.8

2.8

2.9

2.9

70

60

2.2

2.2

2.2

2.3

2.3

2.3

2.3

2.4

2.4

2.4

2.5

2.5

60

50

1.8

1.8

1.9

1.9

1.9

1.9

2.0

2.0

2.0

2.0

2.1

2.1

50

40

1.4

1.5

1.5

1.5

1.5

1.5

1.6

1.6

1.6

1.6

1.6

1.7

40

30

1.1

1.1

1.1

1.1

1.1

1.2

1.2

1.2

1 2

1.2

1.2

1.2

30

20

.7

.7

.7

.8

.8

.8

.8

.8

.8

.8

.8

.8

20

10

4

4

4

4

4

4

4

4

4

4

4

4

10

9

.3

.3

.3

.3

.3

.3

.4

.4

.4

.4

.4

.4

9

8

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

8

7

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

7

6

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

6

5

.2

.2

.2

.2

.2

^

.2

.2

.2

.2

.2

.2

5

4

.1

.1

.1

.2

.2

'2

.2

.2

.2

.2

.2

.2

4

3

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

3

2

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

2

1

1

3.90

3.95

4. CO

4.05

1

3.60

3.65

3.70

3.75

3.80

3.85

4.10

4.15

I

Appendix.

243

Table VII. Pounds of fat in I to 10,000 Ibs. of milk ( Continued}.

1

4.20

4.25

4.30

4.35

4.40

4.45

4.50

4.55

4.60

4.65

4.70

4.75

I

Milk

Milk

Ibs.

Ibs.

10,000

420

425

430

435

440

445

450

455

460

465

470

475

10,000

9,000

378

383

387

392

396

401

405

410

414

419

423

428

9,000

8,000

336

340

344

348

352

356

360

364

368

372

376

380

8,000

7,000

294

298

301

305

308

312

315

319

322

326

329

333

7,000

6,000

252

255

258

261

264

267

270

273

276

279

282

285

6,000

5,000

210

213

215

218

220

223

225

228

230

233

235

238

5,OCO

4,000

168

170

172

174

176

178

180

182

184

186

188

190

4,000

3,000

126

128

129

131

132

134

135

137

138

140

141

143

3,000

2,000

84.0

85.0

86.0

87.0

88.0

89.0

90.0

91.0

92.0

93.0

94.0

95.0

2,000

1,000

42.0

42.5

43.0

43.5

44.0

44.5

45.0

45.5

46.0

46.5

47.0

47.5

1,000

900

37 8

38 3

38 7

39 ?

39 6

40 1

40 5

41 0

41 4

41 9

4?, 3

4fl 8

900

800

33.6

31.0

34.4

34.8

35.2

35.6

36.0

36.4

36.8

37.2

37.6

38.0

800

700

29.4

29.8

30.1

30.5

30.8

31.2

31.5

31.9

32.2

32.6

32.9

33.3

700

600

25.2

25.5

"5.8

26.1

26.4

26.7

27.0

27.3

27.6

27.9

28.2

28.5

600

500

21.0

21.3

21.5

21.8

22.0

22 3

22.5

22.8

23.0

23.3

23.5

23.8

500

400

16.8

17.0

17.2

17.4

17.6

17.8

18.0

18.2

18.4

18.6

18.8

19.0

400

300

12.6

12.8

12.9

13.1

13.2

13.4

13.5

13.7

13.8

14.0

14.1

14.3

300

200

8.4

8.5

8.6

8.7

8.8

8.9

9.0

9.1

9.2

9.3

9.4

9.5

200

100

4.2

4.3

4.3

4.4

4.4

4.5

4.5

4.6

4.6

4.7

4.7

4.8

100

90

3.8

3.8

3.9

3.9

4.0

4.0

4.1

4.1

4.1

4.2

4.2

4.3

90

80

3.4

3.4

3.4

3.5

3.5

3.6

3.6

3.6

3.7

3.7

3.8

3.8

80

70

2.9

3.0

3.0

3.0

3.1

3.1

3.2

3.2

3.2

3.3

3.3

3.3

70

60

2.5

2.6

2.6

2.6

2.6

2.7

2.7

2.7

2.8

2.8

2.8

2.9

60

50

2.1

2.1

2.2

2.2

2.2

2.2

2.3

2.3

2.3

2.3

2.4

2.4

50

40

1 7

1 7

1 7

1 7

1 8

1 8

1 8

1 8

1 8

1 9

1.9

1 9

40

30
20
10

13

.8

1.3
.9

1.3
.9

1.3

.9

1.3

.9

1.3
.9

.9
5

.9
5

.9
5

.9
5

.9
5

1.0
jj

30
20
10

9

4

4

4

4

4

4

4

4

4

4

4

4

9

8

s

3

3

4

4

4

4

4

4

4

4

8

7

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

7

6

.3

.3

.3

.3

.3

.3

.0

.3

.3

.3

.3

.3

6

5

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

5

4

.2

.2

.2

.2

.2

.2

2

.2

.2

.2

.2

.2

4

3

1

1

1

1

1

.1

T

1

1

1

1

1

3

2

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

2

1

1

i

4.20

4.25

4.30

4.35

4.40

4.45

4.50

4.55

4.60

4.65

4.70

4.75

I

244 Testing Milk and Its Products.

Table VII. Pounds of fat in I to 10.000 Ibs. of milk ( Continued}.

J_

4.80

4.85

4.90

4.95

5.00

5.05

5.10

5.15

5.20

5.25

5.30

5.35

I

Milk

Milk

Ibs.

Ibs.

10,000

480

485

490

495

500

505

510

515

520

525

530

535

10,000

9,000

432

437

441

446

450

455

459

464

468

473

477

482

9,000

8,000

384

388

392

396

400

404

408

412

416

420

424

428

8,000

7,000

336

340

343

347

350

354

357

361

364

368

371

375

7,000

6,000

288

291

294

297

300

303

306

309

312

315

318

321

6,000

5,000

240

243

245

248

250

253

255

258

260

263

265

268

5,000

4,000

192

194

196

198

200

202

204

206

208

210

212

214

4,000

3,000

144

146

147

149

150

152

153

155

156

158

159

161

3,000

•2,000

96.0

97.0

98.0

99.0

100

101

102

103

104

105

106

107

2,000

1,000

48.0

48.5

49.0

49.5

50.0

50.5

51.0

51.5

52.0

52.5

53.0

53.5

1,000

900

43.2

43.7

44.1

44.6

45.0

45.5

45.7

46.4

46.8

47.3

47.7

48.2

900

800

38.4

38.8

39.2

39.6

40.0

40.4

40.8

41.2

41.6

42.0

42.4

42.8

800

700

33.6

34.0

34.3

34.7

35.0

35.4

35.7

36.1

36.4

36.8

37.1

37.5

700

600

28.8

29.1

29.4

29.7

30.0

30.3

30.6

30.9

31.2

31.5

31.8

32.1

600

500

24.0

24.3

24.5

24.8

25.0

25.3

25.5

25.8

26.0

26.3

26.5

26.8

500

400

19.2

19.4

19.6

19.8

20.0

20.2

20.4

20.6

20.8

21.0

21.2

21.4

400

300

14.4

14.6

14.7

14.9

15.0

15.2

15.3

15.5

15.6

15.8

15.9

16.1

300

200

9.6

9.7

9.8

9.9

10.0

10.1

10.2

10.3

10.4

10.5

10.6

10.7

200

100

4.8

4.9

4.9

5.0

5.0

5.1

5.1

5.2

5.2

5.3

5.3

5.4

100

90

4.3

4.4

4.4

4.5

4.5

4.5

4.6

4.6

4.7

4.7

4.8

4.8

90

80

3.8

3.9

3.9

4.0

4.0

4.0

4.1

4.1

4.2

4.2

4.2

4.3

80

70

3.4

3.4

3.4

3.5

3.5

3.5

3.6

3.6

3.6

3.7

3.7

3.7

70

60

2.9

2.9

2.9

3.0

3.0

3.0

3.1

3.1

3.1

3.2

3.2

3.2

60

50

2.4

2.4

2.5

2.5

2.5

2.5

2.6

2.6

2.6

2.6

2.7

2.7

50

40

1.9

1.9

2.0

2.0

2.0

2.0

2.0

2.1

2.1

2.1

2.1

2.1

40

30

1.4

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.6

1.6

1.6

1.6

30

20

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.1

1.1

1.1

20

10

.5

.5

.5

.5

.5

.5

.5

.5

.5

.5

.5

.5

10

9

.4

.4

.4

.4

.5

.5

.5

.5

.5

.5

.5

.5

9

7

3

3

3

3

4

4

4

4

4

4

4

4

7

6

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

6

5

.2

.2

.2

.2

.3

.3

.b

.3

.3

.3

.3

.3

5

4

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

4

3

.1

.1

.1

.1

.2

.2

.2

.2

.2

.2

.2

.2

3

2

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

2

1

.1

.1

.1

.1

.1

.1

.1

.1

1

I

4.80

4.85

4.90

4.95

5.00

5.05

5.10

5.15

5.20

5.25

5.30

5.35

|

Appendix.

245

Table VIII. Pounds of fat in I to 1000 Ibs. of cream testing
12.0 to 50.0 per cent. fat.

(See directions for use, p. 240.)

1

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

ll

w"~

1000

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

270

280

290

300

«(K)

108

117

126

135

144

1.53

162

171

180

18«

198

207

216

225

2?*4

243

252

261

270

800

96

104

112

120

128

136

144

152

160

168

176

184

192

200

208

216

224

23*

240

700

84

91

98

105

112

119

126

133

HO

147

154

161

163

175

182

189

196

•208

210

600

72

78

84

90

96

102

108

114

120

126

132

138

144

150

156

162

168

174

180

600

60

65

70

75

80

85

90

95

100

105

110

115

120

125

130

135

140

145

150

400

48

52

56

60

64

68

72

76

80

84

88

92

96

100

104

108

112

116

120

300

36

39

42

45

48

51

54

57

60

63

66

69

72

75

78

81

84

87

90

200

24

26

28

30

32

34

36

38

40

42

44

46

48

50

52

54

6U

58

60

100

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

90

10.8

11.7

12.6

13.5

14.4

15.3

16.2

17.1

18.0

18.9

19.8

20.7

21.6

22.5

23.4

24.3

25.2

26.1

27.0

80

9.6

10.4

11.2

12.0

12.8

13.6

14.4

15.2

16.0

16.8

17.6

18.4

19.2

•20.0

20.8

21.6

22.4

23.2

24.0

70

8.4

9.1

9.8

10.5

11.2

11.9

12.6

13. »

14.0

14.7

15.4

16.1

16.8

17.5

18.2

18.9

19.6

20..3

21.0

60

7.2

7.8

8.4

9.0

9.6

10.2

10.8

11.4

12.0

12.6

13.2

13.8

14.4

15.0

15.6

16.2

16. &

17.4

18.0

50

6.0

6.5

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

12.5

13.0

13.5

14.0

4.5

15,0

40

4.8

5.2

5.6

6.0

6.4

6.8

7.2

7.6

8.0

8.4

8.8

9.2

9.6

10.0

10.4

10.8

11.2

11.6

12,0

30

3.6

3.9

4.2

4.5

4.8

5.1

5.4

5.7

6.0

6.3

6.6

6.9

7.2

7.5

7.8

8.1

8.4

8.7

9.0

20

2.4

2.6

2.8

3.0

3.2

3.4

3.6

4.0

4.2

4.4

4.6

4.8

5.0

5.2

5.4

5.6

5.8

6.0

10

1.2

1.3

1.4

1.5

1.6

1.7

1.8

l!9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

9

1.08

1.17

1.26

1.35

1.44

1.53

1.62

1.71

1.80

1.89

1.98

2.07

2.16

2.25

2.34

1.43

2.52

2.61

2.70

8

.96

1.04

1.12

1.20

1.28

1.36

1.44

1.52

1.60

1.68

1.76

1.84

1.92

2.00

2.08

2.16

2.24

2.32

2.40

7

.84

.91

.98

1.05

1.12

1.19

1.26

1.33

1.40

1.47

1.54

1.61

l.«8

1.75

1.82

1.89

1.96

2.03

2.10

«

.72

.78

.84

.90

.%

1.02

1.08

1.14

1.20

1.26

1.32

1.38

1.44

1.50

1.56

1.62

1.68

1.74

1.80

5

.60

.65

.70

.75

.80

.85

.90

.95

1.00

1.0.5

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

4

.48

.52

.56

.60

.64

.68

.72

.76

.80

.84

.88

.92

.9li

1.00

1.04

1.08

1.12

1.16

1.20

8

.36

.39

.42

.45

.48

.51

.54

.57

.60

.63

.66

.69

.72

.75

.78

.81

-.84

.87

.90

2

.24

.26

.28

.30

.32

.34

.36

.38

.40

.42

.44

.46

.48

.50

.52

.54

.56

.58

.60

1

.12

.13

.14

.15

.16

.17

.18

.19

.20

.21

.22

.23

.24

.25

.26

.27

.28

.29

.30

246

Testing Milk and Its Products.

Table VIII. Pounds of fat in I to 1000 Ibs. of cream (continued}.

i

31

32

88

34

35

86

37

38

39

40

41

42

4?

44

45

46

47

48

49

50

1000

310

320

330

340

350

360

870

380

390

400

410

420

430

440

450

460

470

480

49ft

500

900

279

288

297

306

315

324

333

342

351

360

369

378

387

896

405

414

423

432

441

450

800

248

256

264

272

280

288

296

304

312

320

328

336

344

352

360

368

376

384

892

400

700

217

224

231

238

245

252

259

266

273

280

287

294

301

308

315

322

329

336

343

350

600

186

192

198

204

210

216

222

228

234

240

246

252

258

264

270

276

282

288

294

300

500

155

160

165<

170

175

180

18-5

190

195

200

205

210

215

220

225

230

235

240

245

250

400

124

128

132

136

140

144

148

152

156

160

164

168

172

176

180

184

188

192

196

200

300

93

96

99

102

105

108

111

114

117

120

123

126

129

132

135

138

141

144

147

150

200

62

64

66

68

70

72

74

76

78

80

82

84

86

88

90

92

94

96

98

100

100

31

32

33

34

85

36

87

88

89

40

41

42

43

44

45

46

47

48

49

50

90

27.9

28.8

29.7

30.6

31.5

32.4

33.3

34.2

35.1

86.0

36.9

37.8

38.7

39.6

40.5

41.4

42.3

43.2

44.1

45.0

80

24.8

2i.6

26.4

27.2

28.0

28.8

29.6

30.4

21.2

32.0

32.8

33.6

34.4

a5.2

36.0

36.8

37.638.4

39.2

40.0

70

21.7

22.4

23.1

23.8

24.5

25.2

25.9

26.6

27.3

28.0

28.7

29.4

30.1

30.8

31.532.2

32.933.6

34.3

35.0

60

18.6

19.2

19.8

20.4

21.0

21.6

22.2

22.8

23.4

24.0

24.6

25.2

25.8

26.4

27.0

27.6

28.228.8

29.4

30.0

50

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

21.5

22.0

22.5

23.0

23.524.0

24.5

25.0

40

12.4

12.8

13.2

13.6

14.0

14.4

14.8

15.2

15.6

16.0

16.4

16.8

17.2

17.6

18.0

18.4

18.819.2

19.6

20.0

30

9.3

9.6

9.9

10.2

10.5

10.8

11.1

11.4

11.7

12.0

12.3

12.6

12.9

13.2

13.5

13.8

14.1

14.4

14.7

15.0

20

6.2

6.4

6.6

6.8

7.0

7.2

7.4

7.6

7.8

8.0

8.2

8.4

8.6

8.8

9.0

9.2

9.4

9.6

9.8

10.0

10

3.1

3.2

8.3

3.4

3.5

8.6

8.7

3.8

3.9

4.0

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

5.0

9

2.79

2.88

2.97

3.06

3.15

3.24

3.33

3.42

3.51

3.60

3.69

3.78

3.87

3.96

4.95

4.14

4.23

4.32

4.41

4.50

8

2.48

2.56

2.64

2.72

2.80

2.88

2.96

3.04

3.12

3.20

3.28

3.36

3.44

3.52

3.603.68

3.763.84

3.92

4.00

7

2.17

2.24

2.31

2.38

2.45

2.52

2.59

2.66

2.73

2.80

2.87

2.94

3.01

3.08

3.153.22

3.29

3.36

3.48

3.50

6

1.86

1.92

1.98

2.04

2.10

2.16

2.22

2.28

2.34

2.40

2.46

2.52

2.58

2,64

2.70!2.76

2.82

2.88

2.94

3.00

5

1.55

1.60

1.65

1.70

1.75

1.80

1.85

1.90

1.95

2.00

2.05

2.10

2.15

2.20

2.252.30

2.35

2.40

2.45

2.50

4

1.24

1.28

1.32

1.36

1.40

1.44

1.48

1.52

1.56

1.60

1.64

1.68

1.72

1.76

1.80,1.84

1.88

1.92

1.96

2.00

3

.93

.96

.99

1.02

1.05

1.08

1.11

1.14

1.17

1.20

1.23

1.26

1.29

1.32

1.351.38

1.41

1.44

1.47

1.50

2

.62

.64

.66

.68

.70

.72

.74

.76

.78

.80

.82

.84

.86

.88

.90 .92

.94

.96

.98

1.00

1

.31

.32

.33

.34

.35

.86

.37

.38

.39

.40

.41

.42

.43

.44

.45 .46

.47

.48

.49

.50

Appendix.

247

Table IX. Amount due for butter fat, in dollars and cents, at
12 to 25 cents per pound.

(See directions for use, page 240.)

-1

&§

fl) «-

Pounds of butter fat.

b

S-d

1,000

900

800

700

600

500

400

300

200

100

•* •

§1

P,

?

$

$

1

$

$

$

$

$

$

$

12

120.00

108.00

96.00

84.00

72.00

60.00

48.00

36.00

24.00

12.00

12

12}

122.50

110.25

98.00

85.75

73.50

61.25

49.00

36.75

24.50

12.25

12}

12*

125.00

112.50

100.00

87.50

75.00

62.50

50.00

37.50

25.00

12.50

12*

12f

127.50

114.75

102.00

89.25

76.50

63.75

51.00

38.25

25.50

12.75

12f

13

130.00

117.00

104.00

91.00

78.00

65.00

52.00

39.00

26.00

13.00

13

13}

132.50

119.25

106.00

92.75

79.50

66.25

53.00

39.75

26.50

13.25

13}

13*

135.00

121.50

108.00

94.50

81.00

67.50

54.00

40.50

27.00

13.50

L3*

13f

137.50

123.75

110.00

96.25

82.50

68.75

55.00

41.25

27.50

13.75

14

140.00

126.00

112.00

98.00

84.00

70.00

56.00

42.00

28.00

14.00

14

14}

142.50

128.25

114.00

99.75

85.50

71.25

57.00

42.75

28.50

14.25

14}

14i

145.00

130.50

116.00

101.50

87.00

72.50

58.00

43.50

29.00

14.50

14J

141

147.50

132.75

118.00

103.25

88.50

73.75

59.00

44.25

29.50

14.75

14|

15

150.00

135.00

120.00

105.00

90.00

75.00

60.00

45.00

30.00

15.00

15

15}

152.50

137.25

122.00

106.75

91.50

76.25

61.00

45.75

30.50

15.25

15}

15 i

155.00

139.50

124.00

108.50

93.00

77.50

62.00

46.50

31.00

15.50

15*

15|

157.50

141.75

126.00

110.25

94.50

78.75

63.00

47.25

31.50

15.75

15|

16

160.00

144.00

128.00

112.00

96.00

80.00

64.00

48.00

32.00

16.00

16

16]

162.50

146.25

130.00

113.75

97.50

81.25

65.00

48.75

32.50

16.25

16}

16*

165.00

148.50

132.00

115.50

99.00

82.50

66.00

49.50

33.00

16.50

16|

167.50

150.75

134.00

117.25

100.50

83.75

67.00

50.25

33.50

16.75

16f

17

170.00

153.00

136.00

119.00

102.00

85.00

68.00

51.00

34.00

17.00

17

17}

172.50

155.25

138.00

120.75

103.50

86.25

69.00

51.75

34.50

17.25

17}

17*

175.00

157.50

140.00

122.50

105.00

87.50

70.00

52.50

35.00

17.50

17*

17f

177.50

159.75

142.00

124.25

106.50

87.75

71.00

53.25

35.50

17.75

17|

18

180.00

162.00

144.00

126.00

108.00

90.00

72.00

54.00

36.00

18.00

18

18}

182.50

164.25

146.00

127.75

109.50

91.25

73.00

54.75

36.50

18.25

18}

18*

185.00

166.50

148.00

129.50

111.00

92.50

74.00

55.50

37.00

18.50

18*

187.50

168.75

150.00

131.25

112.50

93.75

75.00

56.25

37.50

18.75

181

V

1,000

900

800

700

600

500

400

300

200

100

•

248

Testing Milk and Its Products.

Table IX. Amount due for butter fat (Continued}.

i

Pounds of butter fet.

Is

Q*O

o«

Pg

El

1,000

900

800

700

600

500

400

300

200

100

^trt

sl

a

?

$"

19

190.00

in. oo

152.00

133.00

114.00

95.00

76.00

57.00

38.00

19.00

19

19J

192.50

173.25

154.00

134.75

115.50

96.25

77.00

57.75

38.50

19.25

19}

19i

195.00

175.50

156.00

136.50

117.00

97.50

78.00

58.50

39.00

19.50

19*

19^

197.50

177.75

158.00

138.25

118.50

98.75

79.00

59.25

39.50

19.75

19|

20

200.00

180.00

160.00

140.00

120.00

100.00

80.00

60.00

40.00

20.00

20

201

202.50

182.25

162.00

141.75

121.50

101.25

81.00

60.75

40.50

20.25

20}

20^

205.00

184.50

164.00

143.50

123.00

102.50

82.00

61.50

41.00

20.50

20*

20f

207.50

186.75

166.00

145.25

124.50

103.75

83.00

62.25

41.50

20.75

20f

21

210.00

189.00

168.00

147.00

126.00

105.00

84.00

63.00

42.00

21.00

21

21}

212.50

191.25

170.00

148.75

127.50

106.25

85.00

63.75

42.50

21.25

211

21

215.00

193.50

172.00

150.50

129.00

107.50

86.00

64.50

43.00

21.50

21*

21

217.50

195.75

174.00

152.25

130.50

108.75

87.00

65.25

43.50

21.75

21|

22

220.00

198.00

176.00

154.00

132.00

110.00

88.00

66.00

44.00

22.00

22

22*

222.50

200.25

178.00

155.75

133.50

111.25

89.00

66.75

44.50

22.25

22}

22*

225.00

202.50

180.00

157.50

135.00

112.50

90.00

67.50

45.00

22.50

22*

22J

227.50

204.75

182.00

159.25

136.50

113.75

91.00

68.25

45.50

22.75

22f

23

230.00

207.00

184.00

161.00

138.00

115.00

92.00

69.00

46.00

23.00

23

23}

232.50

209.25

186.00

162.75

139.50

116.25

93.00

69.75

46.50

23.25

23}

23*

235.00

211.50

188.00

164.50

141.00

117.50

94.00

70.50

47.00

23.50

23*

23|

237.50

213.75

190.00

166.25

142.50

118.75

95.00

71.25

47.50

23.75

23£

24

240.00

216.00

192.00

168.00

144.00

120.00

96.00

72.00

48.00

24.00

24

24}

242.50

218.25

194.00

169.75

145.50

121.25

97.00

72.75

48.50

24.25

24}

24*

245.00

220.50

196.00

171.50

147.00

122.50

98.00

73.50

49.00

24.50

24^

24£

247.50

222.75

198.00

173.25

148.50

123.75

99.00

74.25

49.50

24.75

24f

25

250.00

225.00

200.00

175.00

150.00

125.00

100.00

75.00

50.00

25.00

25

1,000

900

800

700

600

500

400

300

200

100

Appendix.

249

Table X. Relative-value tables.

(See directions for use, pp. 19&-198.

5

li

Price of milk per 100 pounds, in dollars and cents.

B

PH '

3.0

.30

.31

.33

.34

.36

.37

.39

.40

.42

.43

.45

3.1

.31

.33

.34

.36

.37

.39

.40

.42

.43

.45

,4f;

3.2

.32

.34

.35

.37

.38

.40

.42

.43

.45

.46

.4*

3.3

.33

.35

.36

.38

.40

.41

.^3

.45

.46

.48

.40

3.4

.34

.36

.37

.39

.41

.42

.44

.46

.48

.49

.51

3.5

.35

.37

.38

.40

.42

.44

.45

.47

.49

.51

.55

3 6

.36 J

.38

40

41

.43

45

.47

.49

50

52

54

3.7

.37

.39

.41

.43

.44

.46

.48

.50

.52

.54

.55

3.8

.38

.40

.42

.44

.46

.47

.49

.51

.53

.55

.57

3.9

.39

.41

.43

.45

.47

.49

.51

.53

.55

.57

.58

4.0

.40

.42

.44

.46

.48

.50

.52

.54

.56

.58

.6C

4 1

41

43

.45

.47

49

.51

.53

.55

.57

.59

61

4 fl

.42

.44

.46

.48

.50

52

.55

.57

.59

.61

6.°

4.3

.43

.45

.47

.49

.52

.54

.56

.58

.60

.62

.64

4 4

.44

.46

.48

.51

.53

.55

.57

.59

.62

.64

66

4.5

.45

.47

.49

.52

.54

.56

.58

.61

.63

.65

.61

4 6

.46

.48

.51

.53

55

.57

60

.62

.64

67

6J-

4.7

.47

.49

.52

.54

.56

.59

.61

.63

.66

.68

.7C

4.8

.48

.50

.53

.55

58

.60

.62

.65

.67

.70

.72

4.8f

.49

.51

.54

.56

.59

.61

.64

.66

.69

.71

.72

5.0

.50

.52

.55

.57

.60

.62

.65

.67

.70

.72

.75

5.1

.51

.54

.56

.59

.61

.64

.66

.69

.71

.74

.76

5.2

.52

.55

.57

.60

.62

.65

.68

.70

.73

.75

.78

5.3

.53

.56

.58

.61

.64

.66

.69

.72

.74

.77

.79

5.4

.54

.57

.59

.62

.65

.67

.70

.73

.76

.78

.81

5.5

.55

.58

.60

.63

.66

.69

.71

.74

.77

.80

.82

5.6

.56

.59

.62

.64

.67

.70

.73

.76

.78

.81

.84

5.7

.57

.60

.63

.66

.68

.71

.74

.77

.80

.83

.85

5.8

.58

.61

.64

.67

.70

.72

.75

.78

.81

.84

.87

5.9

.59

.62

.65

.68

.71

.74

.77

.80

.83

.86

.88

6.0

.60

.63

.66 -

.60

.72

.75

.78

.81

.84

.87

.90

250

Testing Milk and Its Products.

Table X. Relative-value tables ( Continued).

Percent.
fat.

Price of milk per 100 pounds, in dollars and cents.

3.0
3 1

.46

.48

.48
.50

.49
.51

.51
.53

.52
.54

.54

.56

.55

.57

.57
.59

.58
.60

.60
62

3.2

.50

.51

.53

.54

.56

.58

.59

.61

.62

.64

3.3

.51

.53

.54

.56

.58

.59

.61

.63

.64

.66

3.4

.53

.54

.56

.58

.59

.61

.63

.65

.66

.68

3.5

.54

.56

.58

.59

.61

.63

.65

.66

.68

.70

3.6

.56

.58

.59

.61

.63

.65

.67

.68

.70

.72

3.7

.57

.59

.61

.63

.65

.67

.68

.70

.72

.74

3.8

.59

.61

.63

.65

.66

.68

.70

.72

.74

.76

3.9

.60

.62

.64

.66

.68

.70

.72

.74

.76

.78

4.0

.62

.64

.66

.68

.70

.72

.74

.76

.78

.80

4.1

.64

.66

.68

.70

.72

.74

.76

.78

.80

.82

4.2

.65

.67

.69

.71

.73

.76

.78

.80

.82

.84

4.3

.67

.69

.71

.73

.75

.77

.80

.82

.84

.86

4.4

.68

.70

.73

.75

.77

.79

.81

.84

.86

.88

4.5

.70

.72

.74

.76

.79

.81

.83

.85

.88

.90

4.6

.71

.74

.76

.78

.80

.83

.85

.87

.90

.92

4.7

.73

.75

.78

.80

.82

.85

.87

.89

.92

.94

4.8

.74

.77

.79

.82

.84

.86

.89

.91

.94

.96

4.9

.76

.78

.81

.83

.86

.88

.91

.93

.96

.98

5.0

.77

.80

.82

.85

.87

.90

.92

.95

.97

1.00

5.1

.79

.82

.84

.87

.89

.92

.94

.97

.99

1.02

5.2

.81

.83

.86

.88

.91

.94

.96

.99

1.01

1.04

5.3

.83

.85

.87

.90

.93

.95

.98

1.01

1.03

1.06

5.4

.84

.86

.89

.92

.94

.97

1.00

1.03

1.05

1.08

5.5

.85

.88

.91

.93

.96

.99

1.02

1.04

1.07

1.10

5.6

.87

.90

.92

.95

.98

l.OL

1.04

1.06

1.09

1.12

5.7

.88

.91

.94

.97

1.00

1.03

1.05

1.08

1.11

1.14

5.8

.90

.93

.96

.99

1.01

1.04

1.07

1.10

1.13

1.16

5.9

.91

.94

.97

1.00

1.03

1.06

1.09

1.12

1.15

1.18

6.0

.93

.96

.99

1.02

1.05

1.08

1.11

1.14

1.17

1.20

Appendix.

251

Table X. Relative-value tables (Continued).

In

r

Price of milk per 100 pounds, in dollars and cents.

3.0

.61

.63

.64

.66

.67

.69

.70

.72

.73

.75

3.1

.64

.65

.67

.68

.70

.71

.73

.74

.76

.78

3.2

.66

.67

.69

.70

.72

.74

.75

.77

.78

.80

3.3

.68

.69

.71

.73

.74

.76

.78

.79

.81

.83

3.4

.70

.71

.73

.75

.76

.78

.80

.82

.83

.85

3.5

.72

.73

.75

.77

.79

.80

.82

.84

.86

.88

3.6

.74

.76

.77

.79

.81

.83

.85

.86

.88

.90

3.7

.76

.78

.80

.81

.83

.85

.87

.89

.91

.93

3.8

.78

.80

.82

.84

.85

.87

.89

.91

.93

.95

3.9

.80

.82

.84

.86

.88

.90

.92

.94

.96

.98

4.0

.82

.84

.86

.88

.90

.92

.94

.96

.98

1.00

4.1

.84

.86

.88

.90

.92

.94

.96

.98

1.00

1.03

4.2

.86

.88

.90

.92

.94

.97

.99

1.01

1.03

1.05

4.3

.88

.90

.92

.95

.97

.99

1.01

J.03

1.05

1.08

4.4

.90

.92

.95

.97

.99

1.01

1.03

1.06

1.08

1.10

4.5

.92

.94

.97

.99

1.01

1.03

1.06

1.08

1.10

1.13

4.6

.94

.97

.99

1.01

1.03

1.06

1.08

1.10

1.13

1.15

4.7

.96

.99

1.01

1.03

1.06

1.08

1.10

1.13

1.15

1.18

4.8

.98

1.01

1.03

1.06

1.08

1.10

1.13

1.15

1.18

1.20

4.9

1.00

1.03

1.05

1.08

1.10

1.13

1.15

1.18

1.20

1.23

5.0

1.02

1.05

1.07

1.10

.12

1.15

.18

1.20

1.23

1.25

5.1

1.05

1.07

1.10

1.12

.15

1.17

.20

1.22

1.25

1.27

5.2

1.07

1.09

1.12

1.14

.17

1.20

.22

1.25

1.27

.30

5.3

1.09

1.11

1.14

1.17

.19

1.22

.25

1.27

1.30

.32

5.4

1.11

1.13

1.16

1.19

.21

1.24

.27

1.30

1.32

.35

5.5

1.13

1.15

1.18

1.21

1.24

1.26

.29

1.32

1.35

.38

5.6

1.15

1.18

1.20

1.23

1.26

.29

.32

1.34

1.37

.40

5.7

1.17

1.20

1.23

1.25

1.28

.31

.34

1.37

1.39

.43

5.8

1.19

1.22

1.25

1.28

1.30

.33

.36

1.39

1.42

.45

5.9

1.21

1.24

1.27

1.30

1.33

.36

1.39

1.42

1.45

1.48

6.0

1.23

1.26

1.29

1.32

1.35

.38

1.41

1.44

1.47

1.50

252

Testing Milk and Its Products.

Table X. Relative-value tables (Continued).

la

£

Price of milk per 100 pounds, in dollars and cents.

3.0

.76

.78

.79

.81

.82

.84

.85

.87

.88

.90

3.1

.79

.81

.82

.84

.85

.87

.88

.90

.91

.93

3.2

.82

.83

.85

.86

.88

.90

.91

.93

.94

.96

3.3

.84

.86

.87

.89

.91

.92

.94

.96

.97

.99

3.4

.87

.88

.90

.92

.93

.95

.97

.99

1.00

1.02

3.5

.89

.91

.93

.94

.96

.98

1.00

1.01

1.03

1.05

3.6

.92

.94

.95

.97

.99

1.00

.03

1.04

1.06

1.08

3.7

.94

.96

.98

1.00

1.02

1.03

.05

1.07

1.09

1.11

3.8

.07

.99

1.01

1.03

1.04

1.06

.08

1.10

1.12

1.14

3.9

.99

1.01

1.03

1.05

1.07

1.09

.11

1.13

1.15

1.17

4.0

.02

1.04

1.06

1.08

1.10

1.12

.14

1.16

1.18

1.20

4.1

.05

1.07

1.09

1.11

.13

1.15

.17

1.19

1.21

1.23

4.2

.07

1.09

1.11

1.13

.15

1.18

.20

1.22

1.24

1.26

4.3

.10

1.12

1.14

1.16

.18

1.20

.23

1.25

1.27

.29

4.4

.12

1.14

1.17

1.19

.21

1.23

1.25

1.28

1.30

.32

4.5

.15

1.17

1.19

1.21

.24

1.26

1.28

1.30

1.33

.35

4.6

.17

1.20

.22

1.24

.26

1.29

1.31

1.33

1.36

.38

4.7

1.20

1.22

.25

1.27

.29

1.32

1.34

1.36

1.39

.41

4.8

1.22

1.25

.27

1.30

1.32

1.34

1.37

1.39

1.42

1.44

4.9

1.25

1.27

.30

1.32

1.35

1.37

1.40

1.42

1.45

1.47

5.0

1.27

1.30

.32

1.35

1.37

1.40

1.42

.45

1.47

1.50

5.1

1.30

1.33

.35

1.38

1.40

1.43

1.45

.48

1.50

1.53

5.2

1.33

1.35

1.37

1.40

1.43

1.46

1.48

.51

1.53

1.56

5.3

1.35

1.38

1.40

1.43

1.46

1.48

1.51

.54

1.56

1.59

5.4

1.38

1.40

1.43

1.46

1.48

1.51

1.54

1.57

1.59

1.62

5.5

1.40

1.43

1.46

1.48

1.51

1.54

1.57

1.60

1.62

1.65

5.6

1.43

1.46

1.48

1.51

1.54

1.57

1.60

1.62

1.65

1.68

5.7

1.45

1.48

1.51

1.54

1.57

1.60

1.62

1.65

1.68

1.71

5.8

1.48

1.51

1.54

1.57

1.59

1.62

1.65

1.68

1.71

1.74

5.9

1.50

1.53

1.56

1.59

1.62

1.65

1.68

1.71

1.74

1.77

6.0

1.53

1.56

1.59

1.62

1.65

1.68

1.71

1.74

1.77

1.80

Appendix. 253

Table XL Butter chart, showing calculated yield of butter (in
Ibs.) from I to 10,000 Ibs. of milk, testing 3.0 to 5.3 per
cent. (See directions for use, p. 240.)

8

3.00

3 10

3 20

3 30

3 40

3 50

3 60

3 70

3 80

3 90

4 00

4 10

H

1

Milk,

Milk,

Ibs.

Ibs.

1.0,000

325

336

348

360

371

383

394

406

418

429

441

452

10,000

9,000

293

302

313

324

334

345

355

365

376

386

397

407

9,000

S,000

260

269

278

288

297

306

315

325

334

343

353

362

8,000

7,000

228

235

244

252

260

268

276

284

293

300

309

316

7,000

6,000

195

202

209

216

223

230

236

244

251

257

265

271

6,000

5,000

163

168

174

180

186

192

197

203

209

215

221

226

5,000

4,000

130

134

139

144

148

153

158

162

167

172

176

181

4,000

3,000

97.5

101

104

108

111

115

118

122

125

129

132

136

3,000

2,000

65.0

67.2

69.6

72.0

74.2

76.6

78.8

81.2

83.6

85.8

88.2

90.4

2,000

1,000

32.5

33.6

34.8

36.0

37.1

38.3

39.4

40.6

41.8

43.9

44.1

45.2

1,000

900

29.3

30.2

31.3

32.4

33.4

34.5

35.5

36.5

37.6

38.6

39.7

40.7

900

800

26.0

26.9

27.8

28.8

29.7

30.6

31.5

32.5

33.4

34.3

35.3

36.2

800

700

22.8

23.5

24.4

25.2

26.0

26.8

27.6

28.4

29.3

30.0

30.9

31.6

700

600

19.5

20.2

20.9

21.6

22.3

23.0

23.6

24.4

25. 3

25.7

26.5

27.1

600

500

16.3

16.8

17.4

18.0

18.6

19.2

19.7

20.3

20.9

21.5

22.1

22.6

500

400

13.0

13.4

13.9

14.4

14.8

15.3

15.8

16.2

16.7

17.2

17.6

18.1

400

300

9.7

10.1

10.4

10.8

11.1

11.5

11.8

12.2

12.5

12.9

13.2

13.6

300

200

6.5

6.7

6.9

7.2

7.4

7.6

7.9

8.1

8.3

8.6

8.8

9.0

200

100

3.2

3.4

3.5

3.6

3.7

3.8

3.9

4.1

4.2

4.3

4.4

4.5

100

90

2.9

3.0

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4.1

90

80

2.6

2.7

2.8

2.9

3.0

3.1

3.2

3.3

3.4

3.4

3.5

3.6

80

70

2.3

2.3

2.4

2.5

2.6

2.7

2.8

2.8

2.9

3.0

3.1

3.2

70

60

1.9

2.0

2.1

2.2

2.2

2.3

2.4

2.4

2.5

2.6

2.7

2.7

60

50

1.6

1.7

1.7

1.8

1.9

1.9

2.0

2.0

2.1

2.2

2.2

2.3

50

40

1.3

1.3

1.4

1.4

1.5

1.5

1.6

1.6

1.7

1.7

1.8

1.8

40

30

1.0

1.0

1.0

1.1

1.1

1.2

1.2

1.2

1.3

l!3

1.3

1.4

30

20

.6

.7

.7

.7

.7

.8

.8

.8

.8

.9

.9

.9

20

10

3

3

4

4

4

4

4

4

4

4

4

5

10

9

.3

.3

.3

.3

.3

.3

.4

.4

.4

.4

.4

.4

9

8

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.4

.4

8

7

.2

.2

.2

.3

.3

.3

.3

.3

.3

.3

.3

.0

7

6

.2

.2

.2

.2

.2

.2

.2

.2

.3

.3

.3

.3

6

5

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

r

5

4

.1

.1

.1

.2

.2

.2

.2

.2

.2

.2

.2

2

4

3

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

3

2

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

2

1

1

~T

3.40

3.70

3.80

3.90

4.00

3.00

3.10

3.20

3.30

3.50

3.60

4.10

H

H

P

254

Testing Milk and Its Products.
Table XI. Butter chart ( Continued}.

I

4.20

4.30

4.40

4.50

4.60

4.70

4.80

4.90

5.00

5.10

5.20

5.30

1

Milk

Milk

Ibs.

Ibs.

10,000

464

476

487

499

510

522

534

545

557

568

580

592

10,000

9,000

418

428

438

449

459

470

481

491

501

511

522

533

9,000

8,000

371

381

390

399

408

418

427

436

446

454

464

474

8,000

7,000

325

333

341

349

357

365

374

382

390

398

406

414

7,000

6,000

278

286

292

299

306

313

320

327

334

341

348

355

6,000

5,000

232

238

244

250

255

261

267

273

279

284

290

296

5,000

4,000

186

190

195

200

204

209

214

218

223

227

232

237

4,000

3,000

139

143

146

150

153

157

160

164

167

170

174

178

3,000

2,000

92.8

95.2

97.4

99.8

102

104

107

109

111

114

116

118

2,000

1,000

46.4

47.6

48.7

49.9

51.0

52.2

53.4

54.5

55.7

56.8

58.0

59.2

1,000

900

41.8

42.8

43.8

44.9

45.9

47.0

48.1

49.1

50.1

51.1

52.2

)3.3

900

800

37.1

38.1

39.0

39.9

40.8

41.8

42.7

43.6

44.6

45.4

46.4

47.4

800

700

32.5

33.3

34.1

34.9

35.7

36.5

37.4

38.2

39.0

39.8

40.6

41.4

700

600

27.8

28.6

29.2

29.9

30.6

31.3

32.0

32.7

3:3.4

34.1

34.8

35.5

600

500

23.2

23.8

24.4

25.0

25.5

26.1

26.7

27.3

27.9

28.4

29.0

29.6

500

400

18.6

19.0

19.5

20.0

20.4

20.9

21.4

21.8

22.3

22.7

23.2

23.7

400

300

13.9

14.3

14.6

15.0

15.3

15.7

16.0

16. 4

16.7

17.0

17.4

17.8

300

200

9.3

9.5

9.7

10.0

10.2

10.4

10.7

10.9

11.1

11.4

11.6

11.8

200

100

4.6

4.8

4.9

5.0

5.1

5.2

5.3

5.5

5.6

5.7

5.b

5.9

100

90

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

5.0

5.1

5.2

5.3

90

80

3.7

3.8

3.9

4.0

4.1

4.2

4.8

4.4

4.5

4.5

4.6

4.7

80

70

3.3

3.3

3.4

3.5

3.6

3.7

3.7

3.8

3.9

4.0

4.1

4.1

70

60

2.8

2.9

2.9

3.0

3.1

3.1

3.2

3.3

3.3

3.4

3.5

3.6

60

50

2.3

2.4

2.4

2.5

2.6

2.6

2.7

2.7

2.8

2.8

2.9

3.0

50

40

1.9

1.9

2.0

2.0

2.0

2.1

2.1

2.2

2.2

2.3

2.3

2.4

40

30

1.4

1.4

1.5

1.5

1.5

1.6

1.6

1.6

1.7

1.7

1.7

1.8

30

20

.9

1.0

1.0

1.0

1.0

1.0

1.1

1.1

1 1

1.1

1.2

1.2

20

10

.5

.5

.5

.5

.5

.5

.5

.6

.6

.6

.6

.6

10

9

.4

.4

.4

.5

.5

.5

.5

.5

.5

.5

.5

.5

9

8

4

4

4

4

4

4

.4

4

5

5

5

8

7

.3

.3

.3

.4

.4

.4

.4

.4

.4

.4

.4

.4

7

6

.3

.3

.3

.3

.3

.3

.3

.3

.3

.3

.4

.4

6

5

.2

.2

.2

.3

.3

.3

.3

.3

.3

.3

.3

.3

5

4

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

4

3

.1

.1

.2

.2

.2

.2

.2

t\
. z

.2

.2

.2

.2

3

2

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

2

1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

.1

1

1

4.20

4.30

4.40

4.50

4.60

4.70

4.80

4.90

5. CO

5.10

5.20

5.30

T~

Appendix.

255

Table XII. Overrun table, showing pounds of butter from
one hundred Ibs. of milk. (See directions for use,
p. 186.)

Per

Per

cent.

1.10

1.11

1.12

1.13

1.14

1.15

1.16

1.17

1.18

1.19

1.20

cent.

fat.

fut.

3.0

3.30

3.33

3.36

3.39

3.42

3.45

3.48

3.51

3.54

3.57

3.60

3.0

3.1

3.41

3.44

3.47

3.50

3.53

3.57

3.60

3.63

3.66

3.68

3.72

3.1

3.2

3.52

3.55

3.58

3.62

3.65

3.68

3.71

3.74

3.78

3.81

3.84

3.2

3 3

3 63

3 66

3 70

3 73

3 76

S 80

3 83

3 86

3 89

3 93

3 96

3.3

3.4

3.74

3.77

3.81

3.84

3.88

3.91

3.94

3.98

4.01

4.05

4.08

3.4

3.5

3.85

3.89

3.92

3.96

3.99

4.03

4.06

4.10

4.13

4.17

4.20

3.5

3.6

3.96

4.00

4.03

4.07

4.10

4.14

4.18

4.21

4.25

4.28

4.31:

3.6

3 7

4 07

4 11

4 14

4 18

4 99

4 ?6

4 *>o,

4 33

4 37

4 40

4 44

3.7

3.8

4.18

4.22

4.26

4.29

4.33

4.37

4.41

4.45

4.48

4.52

4.56

3.8

3.9

4.29

4.33

4.37

4.41

4.45

4.49

4.52

4.56

4.60

4.64

4.68

3.9

4.0

4.40

4.44

4.48

4.52

4.56

4.60

4.64

4.68

4.72

4.76

4.80

4.0

4.1

4.51

4.55

4.59

4.63

4.67

4.72

4.76

4.80

4.84

4.88

4.92

4.1

4.2

4.62

4.66

4.70

4.75

4.79

4.83

4.87

4.91

4.96

->.oo

5.04

4.2

4.3

4.73

4.77

4.82

4.86

4.90

4.95

4.99

5.03

5.07

5.12

5.16

4.3

4.4

4.84

4.88

4.93

4.97

5.02

5.06

•5.10

5.15

5.19

5.24

5.28

4.4

4.5

4.95

5.00

5.04

5.09

5.13

5.18

5.22

5.27

5.31

5.36

5.40

4.5

4.6

5.06

5.11

5.15

5.20

5.24

5.29

5.34

5.38

5.43

5.47

5.52

4.6

4.7

5.17

5.22

5.26

5.31

5.36

5.41

5.45

5.49

5.55

5.59

5.64

4.7

4.8

5.28

5.33

5.38

5.42

5.47

5.52

5.57

5.62

5.66

5.71

5.7h

4.8

4.9

5.39

5.44

5.49

5.54

5.59

5.64

5.68

5.73

5.78

5.83

5.88

4.9

5.0

5.50

5.55

5.60

5.65

5.70

5.75

5.80

5.85

5.90

5.95

6.00

5.0

5.1

5.61

5.66

5.71

5.76

5.81

5.87

5.92

5.97

6.02

6.07

6.12

5.1

5.2

5.72

5.77

5.82

5.88

5.93

5.98

6.03

6.08

6.14

6.19

6.24

5.2

5.3

5.83

5.88

5.94

5.99

6.04

6.10

6.15

6.20

6.25

6.31

6.36

5.3

5.4

5.94

5.99

6.05

6.10

6.16

6.21

6.26

6.32

6.37

6.43

6.48

5.4

5.5

6.05

6.11

6.16

6.22

6.27

6.33

6.38

6.44

6.49

6.55

6.60

5.5

5.6

6.16

6.22

6.27

6.33

6.38

6.44

6.50

6.55

6.61

6.66

6.72

5.6

5.7

6.27

6.33

6.38

6.44

6.50

6.56

6.61

6.67

6.73

6.78

6.84

5.7

5.8

6.38

6.44

6.50

6.55

6.61

6.67

6.73

6.79

6.84

6.90

6.96

5.8

5.9

6.49

6.55

6.61

6.67

6.73

6.79

6.84

6.90

6.96

7.02

7.08

5.9

6.0

6.60

6.666.72

6.78

^.84

6.90

6.96

7.02

7.08

7.14

7.20

6.0

256

Testing Milk and Its Products.

Table XIII. Yield of cheese, corresponding to 2.5 to 6 per cent,
of fat, with lactometer readings from 26 to 36. (See p. 188.)

J

Ijj

LCTOMI

:TEB r

EGREl

:s.

^

C5+i

I*

26

27

28

29

30

31

32

33

34

35

36

I*

2.5

7.28

7.41

7.54

7.67

7.81

7.94

8.07

8.20

8.33

8.47

8.60

2.5

2.6

7.44

7.57

7.70

7.83

7.96

8.09

8.22

8.35

8.49

8.62

8.76

2.6

2.7

7.59

7.72

7.85

7.99

8.12

8.25

8.38

8.51

8.64

8.77

8.91

2.7

2 8

7.74

7.87

8.00

8.14

8.27

8.40

8.53

8.67

8.80

8.94

9 07

91 8

2 9

7.90

8.03

8.16

8.30

8.44

8.56

8.69

8.82

8.95

9.09

9.22

•? 9

3.0

8.05

8.18

8.31

8.4o

8.58

8.71

8.84

8.97

9.11

9.24

9.37

3.0

3.1

8.21

8.34

8.47

8.60

8.74

8.87

9.00

9.13

9.26

9.39

9.53

3.1

3.2

8.36

8.4»

8.62

8.75

8.89

9.02

9.15

9.28

9.42

9.55

9.68

3.2

3.3

8.52

8.65

8.78

8.91

9.05

9.18

9.31

9.44

9.57

9.70

9.84

3.3

3.4

8.67

8.80

8.93

9.06

9.20

9.33

9.46

9.59

9.73

9.86

9.99

3.4

3.5

8.82

8.96

9.09

9.22

9.35

9.48

9.62

9.75

9.88

10.01

10.15

3.5

3.6

8.98

9.11

9.24

9.37

9.50

9.63

9.77

9.90

10.03

10.17

10.30

3.6

3.7

9.13

9.26

9.39

9.52

9.65

9.78

9.92

10.05

10.19

10.32

10.46

3.7

3>

9.29

9.42

9.55

9.68

9.81

9.94

lo. Oh

10.21

10.34

10.48

10.61

3.8

3.9

9.44

9.57

9.70

9.84

9.97

10.10

10.23

10.36

10.50

10.64

10.77

3.9

4.0

9.60

9.73

9.86

10.00

10.13

10.26

10.39

10.53

10.66

10.79

10.93

4.0

4.1

9.75

9.88

10.02

10.15

10.28

10.39

10.54

10.68

10.81

10.94

11.08

4.1

4.2

9.90

10.03

10.17

10.30

10.43

10.57

10.70

10.84

10.97

11.10

11.24

4.2

4.3

10.06

10.19

10.32

10.45

10.58

10.72

10.85

10.99

11.12

11.25

11.39

4.3

4.4

10.21

10.34

10.48

10.61

10.74

10.87

11.00

11.14

11.27

11.41

11.55

4.4

4.5

10.36

10.49

10.63

10.76

10.89

11.03

11.16

11.29

11.42

11.56

11.70

4.5

4.6

10.52

10.65

10.78

10.92

11.05

11.18

11.31

11.45

11.58

11.71

11.85

4.6

4.7

10.67

10.81

10.94

11.07

11.20

11.34

11.47

11.60

11.73

11.87

12.01

4.7

4.8

10.83

10.96

11.09

11.22

11.36

11.49

11.62

11.76

11.89

12.02

12.16

4.8

4.9

10.98

11.11

11.25

11.38

11.51

11.65

11.78

11.91

12.04

12.18

12.32

4.9

5.0

11.14

11.27

11.40

11.54

11.67

11.80

11.93

12.07

12.20

12.34

12.48

5.0

5.1

11.29

11.42

11.55

11.69

11.82

11.96

12.09

12.23

12.36

12.49

12.63

5.1

5.2

11.45

11.58

11.71

11.85

11.98

12.11

12.24

12.38

12.52

12.66

12.80

5.2

5.3

11.60

11.73

11.86

11.99

12.13

12.27

12.40

12.53

12.67

12.71

12.85

5.3

5.4

11.76

11.89

12.02

12.16

12.29

12.42

12.55

12.69

12.83

12.97

13.01

5.4

5.5

11.91

12.04

12.17

12.31

12.44

12.58

12.71

12.85

12.99

13.12

13.25

5.5

5.6

12.07

12.20

12.33

12.47

12.60

12.73

12.87

13.00

13.14

13.28

13.41

5.6

5.7

12.22

12.35

12.48

12.62

12.75

12.89

13.02

13.16

13.30

13.44

13.57

>.7

5.8

12.38

12.51

12.64

12.77

12.91

13.05

13.18

13.31

13.45

13.59

13.72

5.8

5.9

12.53

12.66

12.79

12.93

13.06

13.19

13.33

13.47

13.60

13.74

13.87

5.9

6.0

12.69

12.82

12.95

13.09

13.22

13.35

13.49

13.62

13.75

13.89

14.02

6.0

Appendix.

257

fable XIV. Comparisons of Fahrenheit and Centigrade
(Celsius) thermometer scales.

Fahren-
heit.

Centi-
grade.

Fahren-
heit.

Centi-
grade.

Fahren-
heit.

Centi-
grade.

+212

+100

+176

+80

+140

+60

211

99.44

175

79.44

139

59.44

210

98.89

174

78.89

138

58.89

209

98.33

173

78.33

137

58.33

208

97.78

172

77.78

136

57.78

207

97.22

171

77.22

135

57.22

206

96.67

170

76.67

134

56.67

205

96.11

169

76.11

133

56.11

204

95.55

168

75.55

132

55.55

203

95

167

75

131

55

202

94.44

166

74.44

130

54.44

201

93.89

165

73.89

129

53.89

200

93.33

164

72.33

128

53.33

199

92.78

163

72.78

127

52.78

198

92.22

162

71.22

126

52.22

197

91.67

161

71.67

125

51.67

196

91.11

160

71.11

124

51.11

195

90.55

159

70.55

123

50.55

194

90

158

70

122

50

193

89.44

157

69.44

121

49.44

192

88.89

156

68.89

120

48.89

191

88.33

155

68.33

119

48.33

190

87.78

154

67.78

118

47.78

189

87.22

153

67.22

117

47.22

188

86.67

152

66.67

116

46.67

187

86.11

151

66.11

115

46.11

186

85.55

150

65.55

114

45.55

185

85

149

65

113

45

184

84.44

148

64.44

112

44.44

183

83.89

147

63.89

111

43.89

182

83.33

146

63.33

110

43.33

181

82.78

145

62.78

109

42.78

180

82.22

144

62.22

108

42.22

179

81.67

143

61.67

107

41.67

178

81.11

142

61.11

106

41.11

177

80.55

141

60.55

105

40.55

258

Testing Milk and Its Products.

Table XIV. Comparisons of thermometer scales ( Continued. )

Fahren-
heit.

Centi-
grade.

Fahren-
heit.

Centi-
grade.

Fahren-
heit.

Centi-
grade.

+104

+40

+68

+20

+32

+o

103

39.44

67

19.44

31

—0.55

102

38.89

66

18.89

30

1.11

101

38.33

65

18.33

29

1.67

100

37.78

64

17.78

28

2.22

99

37.22

63

17.22

27

2.78

' 98

36.67

62

16.67

26

3.33

97

36.11

61

16.11

25

3.89

96

35.55

60

15.55

24

4.44

95

35

59

15

23

5

94

34.44

58

14.44

22

5.55

93

33.89

57

13.89

21

6.11

92

33.33

56

13.33

20

6.67

91

32.78

55

12.78

19

7.22

90

32 22

54

12.22

18

7.78

89

31.67

53

11.67

17

8.33

88

31.11

52

11.11

16

8.89

87

30.55

51

10.55

15

9.44

86

30

50

10

14

10

85

29.44

49

9.44

13

10.55

84

28.89

48

8.89

12

11.11

83

28.33

47

8.33

11

11.67

82

27.78

46

7.78

10

12.22

81

27.22

45

7.22

9

12.78

80

26.67

44

6.67

8

13.33

79

26.11

43

6.11

7

13.89

78

25.55

42

5.55

6

14.44

77

25

41

5

5

15.00

76

24.44

40

4.44

4

15.55

75

23.89

39

3.89

3

16.11

74

23.33

38

3.33

2

16.67

73

22.78

37

2.78

1

17.22

72

22.22

36

2.22

0

17.78

71

21.67

35

1.67

—1

18.33

70

21.11

34

1.11

2

18.89

69

20.55

33

0.55

3

19.44

To convert deg. Fahrenheit to corresponding deg. Centigrade:
Subtract 32, multiply difference by 5, and divide by 9.
Example: Which degree Centigrade corresponds to 110° F.? 110 — 32 =

78; 78 X 5 = 390; 390 -i- 9 = 43.33.

To convert deg. Centigrade to corresponding deg. Fahrenheit:
Multiply by 9, divide product by 5, and add 32 to quotient.
Example: Which degree Fahrenheit corresponds to 95.5° C.? 95.5 X 9 =

859.5; 869.5 -H 5 = 171.9; 171.9 + 32 = 203.6.

Appendix.

259

Table XV. Comparison of metric and customary weights and

measures.

Customary
weights and
measures.

Equivalents in
metric system.

Metric weights
and
measures.

Equivalents in
customary system.

inch

2.54 centimeters.
.3048 meter.
1.6094 kilometers.
6.452 sq. centimeters.
9.29 sq. decimeters.
.836 sq. meter.
.4047 hectare.
16.387 cc.
.0283 cub. meter.
.765 cub. meter.
.3552 hectoliter.
29.57 cc.
.9464 liter.
3.7854 liters.
64.8 milligrams.
28.35 grams.
.4536 kilogram.

1 meter

39.37 inches.
1.0936 yards.
.6214 mile.
.155 sq. inch.
10. 764 sq. feet.
1.196 sq. yards.
2.471 acres.
.061 cubic inch.
61.023 cubic inches.
35.314 cub. feet.
2.8377 bushels.
.0338 fluid ounce.
1.0567 quarts.
2.6417 quarts.
15.43 grains.
.035274 ounce.
2. 2046 pounds (av.)

foot

1 meter

mile

1 kilometer
1 sq. centimeter
1 square meter..
1 square meter..
1 hectare

square inch.,
square foot ..
square yard,
acre

cubic inch...
cubic foot....
1 cubic yard...
1 bushel

1 cc

1 cub. decimeter
1 cub. meter
1 hectoliter
1 cc

1 fluid ounce..
1 quart

1 liter

1 gallon .

1 decaliter
1 eram.

1 grain

1 ounce (av.)..
1 pound (av.)

1 gram

1 kilogram

2GO Testing Milk and Its Products.

SUGGESTIONS regarding the organization of co-operative
creameries and cheese factories.

When the farmers of a neighborhood are considering the
establishment of a creamery or cheese factory, they should first
of all make an accurate canvas of the locality to ascertain the
number of cows that can be depended on to supply the factory
with milk. The area which may be drawn from will vary
according to the kind of factory which it is desired to operate.
A successful separator creamery will need at least 400 cows
within a radius of four to five miles from the proposed factory.1
Small cheese factories can be operated with less milk, and
gathered-cream and butter factories generally cover a much
larger territory than that mentioned. In all cases, however,
the question of the number of cows contributing to the enter-
prise must be fully settled before further steps are taken, since
this is a point upon which success will largely depend.

Methods of organization. The farmers should form their own
organization, and not accept articles of agreement proposed by
traveling agents. An agreement to supply milk from a stated
number of cows should be signed by all expecting to join the
association. When a sufficient number of cows has been
pledged to insure the successful operation of a factory, the farm-
ers agreeing to supply milk should meet and form an organi-
zation. This may be done according to either of the following
plans which have been known to give good satisfaction.

Raising money for building and equipment.

First. — Each member will sign an agreement to pay on or
before a given date for a certain number of shares in the com-
pany at dollars per share; or,

Second. — An elected board of directors may be authorized to

borrow a sum of money not exceeding thousand dollars

on their individual responsibility, and the sum of cents,

(usually five cents) per hundred pounds of milk received at
the factory shall be reserved for the payment of this borrowed
money.

ifiull. 56, Wisconsin experiment station.

Appendix. 261

Constitution and by-laws of a co-operative association are drawn
up and signed by the prospective members of the association
when it has been determined to form such an association. It
is impossible to include in an illustration all the articles and
rules that may be found useful in each particular instance; the
following suggestions in regard to some of the points to be in-
cluded in the documents are given as a guide only. It may be
found advisable to modify them in various ways to meet the
needs of the organization to be formed.

After the constitution and by-laws have been drawn up and
made plain to all the members of the association, they should
be printed and copies distributed to all parties interested.

CONSTITUTION

OB
ARTICLES OF AGREEMENT OF THE ASSOCIATION.*

1. The undersigned, residents within the Counties of ,

State of , hereby agree to become members of the

Co-operative Association, which is formed for the purpose of
manufacturing butter or cheese from whole milk.

2. The regular meetings of the association shall be held an-
nually on the day of the month of Special

meetings may be called by the president, or on written request
of one-third of the members of the association, provided three
day's notice of such meeting is sent to all members.

Meetings of the board of directors may be called in the same
way, either by the president or by any two members of the
board of directors.

3. Ten members of the association, or three of the board of
directors, shall constitute a quorum for the transaction of busi-
ness.

4. The officers of the association shall include president, sec-
retary, treasurer, one of whom is also elected manager, and
these officers together with three other members of the associa-

iThe following publications have been freely used in preparing this
constitution and by-laws: Woll, Handbook f. Farmers and Dairymen;
Minn, experiment station, bull. No. 35; Ontario Agriculture College, spec-
ial bulletin, May 1897.

2G2 Testing Milk and Its Products.

tion shall constitute the board of directors. Each of these six
officers shall be elected at the annual meeting and hold office
for one year, or until their successors have been elected and
qualified. Any vacancies in the board of directors may be filled
by the directors until the next annual meeting of the association.

5. The duties of the president shall be to preside at all meet-
ings of the association, and perform the usual duties of such
presiding officers. He shall sign all drafts and documents of
any kind relating to the business of the association, and pay
all money which comes into his possession by virtue of his
office, to the treasurer, taking his receipt therefor. He shall
call special meetings of the association when deemed necessary.

In the absence of the president, one of the board of directors
shall temporarily fill the position.

6. The secretary shall attend all business meetings of the
association and of the board of directors and shall keep a care-
ful record of the minutes of the meetings. He shall also give
notices of all meetings and all appointments on committees,
etc. He shall sign all papers issued, conduct the correspond-
ence and general business of the association, and keep a correct
financial account between the association and its members. He
shall have charge of all property of the association not other-
wise disposed of, give bonds for the faithful performance of his
duties, and receive such compensation for his services as the
board of directors may determine.

7. The treasurer shall receive and give receipt for all money
belonging to the association, and pay out the same upon orders
signed by the president and the secretary. He shall give such
bonds as the board of directors may require.

8. The board of directors shall audit the accounts of the
association, invest its funds, appoint agents, and determine all
compensations. They shall prescribe and enforce the rules and
regulations of the factory. They shall cause to be kept a rec-
ord of the weights and tests of the milk or cream received from
each patron, the products sold, the running expenses, etc., and
si all divide among the patrons the money due them each
month. They shall also make some provision for the with-

Appendix. 2 33

drawal of any member from the association, and make a report
in detail to the association at the annual meeting. Such report
shall include the gross amount of milk handled during the
year, the receipts from products sold, and all other receipts, the
amounts paid for milk and for running expenses, and a com-
plete statement of all other matters pertaining to the business
of the association.

9. Among the rules and regulations to be enforced by the
board of directors may be included some or all of the following:

a. Patrons shall furnish all the milk from all the cows prom-
ised at organization of the association.

b. Only sweet and pure milk will be accepted at the factory,
and any tainted or sour milk shall be refused.

c. The milk of each patron shall be tested at least three times
a month.

d. Any patron proved to be guilty of watering, skimming or
otherwise adulterating the milk sent to the factory, or by tak-
ing more than 80 pounds of skim milk or whey for every 100
pounds of whole milk delivered to the factory, shall be fined as
agreed by the association.

e. A partron's premises may be inspected at any time by the
board of directors, or their authorized agent, for the purpose of
suggesting improvements in the methods of caring for the milk
or the cows, in drainage and general cleanliness; or to secure
samples of the milk of his cows for examination when it is
deemed necessary.

10. Any changes or amendments to the by-laws or constitu-
tion of the association must be made in writing by the parties
proposing the same, and posted prominently in a conspicuous
place at the creamery, at least two weeks previous to their being
acted upon. Such changes to be in force must be adopted by a
two-thirds vote of the stockholders.

11. In voting at any annual or special meeting of the asso-
ciation, the members shall be entitled to one vote for each cow
supplying milk to the factory, or for each share of the stock
owned by them, as agreed upon.

INDEX.

The figures refer to pages in the book.

Acid measures, 33, 46, 54.
Acid tester, Swedish, 66.
Acidity of cream, 118; estimation

of, 123.

Acidity of milk, cause of, 108; de-
termination of, 109, 213; methods

of testing, 120.

Accuracy of alkaline tablets, 117.
Adulteration of milk, 101, 106, 224;

calculation of, 106.
Adulterated butter, 219; cheese, 223.
Albumen, 15; determination of, in

milk, 209, 211.
Albuminoids, 15.
Albumose, 16.
Alkaline tablet test, 113; standard

solution of, 116; accuracy, 117,
Alkaline tabs, 124.
American cheddar cheese, 22.
Amphoteric reaction of milk, 108.
Analysis, chemical, of butter, 216,

217; butter milk, 2:3; cheese, 222;

condensed milk, 215; cream, 213;

milk, 204; skim milk, 213; whey,

213.

Appendix, 233.

Artificial butter, detection of, 219.
Ash, determination of, in butter,

217, 218; in cheese, 223; in milk, 17,

212.

Babcock test, the, 6, 28; Bartlett's
modification of, 72; directions for,
29; discussion of details, 37; for
butter milk, 89; for cheese, 89; for
condensed milk, 90; for cream, 74,
169; for skim milk, 85; for whey,
89; glassware used in, 38; modifi-
cations of, 71; scales for weighing
cream, cheese, etc., 82; water to be
used in, 69.

Bartlett's modification of Babcock
test, 72.

Bausch and Lomb centrifuge, 73.

Beimling test, 5. '

Bi-carbonate of soda, detection of,
in milk, 229.

Bi-cromate of potash, 98, 156; solu-
tion of, 99.

Board of health degrees, 97, 236.

Boiled milk, detection of, 227.

Boracic acid, in dairy products, 124,
228.

Borax in dairy products, 228.

B. & W. bottle, 87.

Butter, artificial, 13; detection of,
219.

Butter chart, 253; use of, 185.

Butter, 20; chemical analysis of,
216; complete analysis in same
sample, 217; composition of, 21,
233; determination of ash, 217;
casein, 216; fat, 216; water, 216;
renovated, 222; sampling for analy-
sis, 216; variations in composition,
177; yield, calculation of, 176.

Butter fat, conversion factor for,
183; determination of specific
gravity, 220; volatile fatty acids,
220; expansion co-efficient, 36;
price per pound, 190; specific grav-
ity, 38; table showing amounts
due for, at 12 to 25 cents per pound,
247; test and yield of butter, 176,

Butter making, quantities of pro-
ducts obtained in, 21.

Butter milk, 21; Babcock test for,
89; chemical analysis of, 213; com-
position of, 233; specific gravity
Of, 214.

Calculation of adulteration, 106; of
concentration of condensed milk,
216; of milk solids, 99, 100; of over-
run, 183; of sp. gr. of milk solids,
103; of yield of butter, 176, 182, 184;
of cheese, 187; of dividends, at
creameries, 190; at cheese factor-
tories, 199; of percentages, 159.

Calibration of glassware, 47.

Carbohydrates, 16.

Casein, 14; determination of, in but-
ter, 216; in cheese, 223; in milk,
209, 211.

Centrifugal machines, 54.

Chamberland filters, 15.

Cheddar cheese, American, 22; com-
position, 233.

Index.

265

Cheese, 22; Babcock test for, 89; cal-
culating yield of, from casein and
fat, 189; from fat, 187; from solids
not fat and fat, 188; composition,
233; chemical analysis of, 222; de-
termination of ash, 223; casein,
223; fat, 222; water, 222; " filled,"
detection of, 223; quality of, from
milk of different richness, 200;
sampling, 89; yield, calculation
of, 187; yield of, and quality of
milk, relation between, 188.

Cheese factories, calculating divi-
dends at, 199; co-operative, 202;
proprietary, 202.

Cholesterin in milk, 19.

Citric acid in milk, 19.

Cleaning solutions for test bot-
tles, 43.

Cleaning test bottles, 40; apparatus
for, 42.

Cochran's test, 5.

Coloring matter in milk, foreign,
detection of, 226.

Colostrum milk, 19; composition
of, 233.

Composite samples, 148; care of, 158;
case for holding, 154; methods of
taking, 148; preservatives for, 155.

Composite sampling, accuracy of,
154; use of drip sample, 150; one-
third sample pipette, 153; Scovell
sampling, tube, 151; tin dipper,
149; equity milk sampler, 153.

Composition of butter, 233; butter
milk, 233; cheese, 233; colostrum
milk, 233; condensed milk, 233;
cream, 233; milk, 233; skim milk,
233; whey, 233.

Condensed milk, 22; analysis of,
215; composition of, 233; determi-
nation of concentration, 216; of
sp. gr. of, 215; testing of, 90, 91.

Control sample of milk, 101;

Conversion factor for butter fat, 183;

Conversion tables for thermometer
scales, 257; for weights and meas-
ures, 258.

Cows, number of tests required in
testing, 136; when to test, 13$.

Cows' milk, composition of, 19, 233.

Cream, 20; acidity of, 120; avoiding
errors of measuring in testing, 75;
Babcock test for, 74, 169; bottles,
the bulb-necked, 78; the Winton,
79; care in sampling, necessity of,
171; determination of acidity of,
114, 123; errors of measuring in
testing, 75; gelatine in, detection
of, 227; pasteurized, detection of,
226; separator, 20; separation of,
influence of temperature, 174;
spaces, 165; specific gravity, 76;
starch in, 228; testing, 74; testing
outfit, 170; testing at creameries,
165; use of 5 cc. pipette in, 81; use
of milk test bottles in, 80; test bot-
tles, 78; weighing, in cream test-
ing, 81; weight of, delivered by a
17.6 cc. pipette, 76.

Creameries, calculating dividends
at, 190, 192; co-operative, 191; cream
testing at, 165; proprietary, 191.

Creamery inch, 1, 167.

Curd test, the Wisconsin improved,
125.

DeLaval's butyrometer, 8.

Devarda's acidimeter, 113.

Diameter of tester and speed re-
quired, relation between, 57.

Dividends, calcinating, at cheese
factories, 199; at creameries, 190;
of both milk and cream at the
same factory, 198.

Dividers, 37.

Double-necked test bottles, 87; value
of divisions of, 87.

Draining rack for test bottles, 43.

Equity milk sampler, 153.
Expansion coefficient for butter
fat, 36.

Failyer and Willard's test, 5.

Farrington's alkaline tablet test,
113.

Fat, 12; color of, an index to strength
of acid used, 67; content, causes of
variation in, 135; determination
of, in butter, 216; in cheese, 222; in
milk, 208; globules, 12; influence

266

Testing Milk and Its Products.

of temperature on separation of,
69; measuring of, in cream test-
ing, 83; in milk testing, 35; pounds
in 1-10,000 Ibs. of milk, testing 3 to
5.35 per cent., 241; speed required
for complete separation of, 56.

Fermentation test, the, 128.

Filled cheese, detection of, 223.

" Fitch's Salt Analysis," 218.

Fjord's centrifugal cream test, 9.

Fluorids detection of, in milk, 230.

Food, influence of, on quality of
milk, 143, 145.

Fool pipettes, 45.

Formalin, detection of, in milk, 230.

Frozen milk, sampling of, 27.

Gauges of cream, 165.

Gelatine in cream, detection of, 227.

Gerber's acid-butyrometer, 7; fer-
mentation test, 128.

Glassware used in the Babcock test,
38; calibration of, 47.

Globulin, 15.

Glycerides of fatty acids, 13.

Goat cheese, 14.

Grain-feeding, heavy, influence of,
on quality of milk, 143.

Gurler's method of testing cows, 136.

Hand testers, 59.

Hemi-albumose, 15.

Herd milk,variationsin, 142; ranges

in variation of, 143.
Hypoxanthin, 19.

Introduction, 1.
Iowa station test, 5.

Lactic acid in milk, 16.

Lactocrite, 5, 8.

Lactose, 16.

Lactochrome, 19.

Lactometer, the, and its applica-
cation, 93; bi-chromate, influence
on, 98; cleaning of, 99; degrees, 94;
N. Y. board of health, 96, 236; Q,ue-
venne, 93; reading the, 97; time of
taking readings, 98.

Lecithin in milk, 19.

LefFmann and Beam test, 5.

Legal standards for milk, 102; 235.

Liebermann's method, 5.

Manns' test, 110.

Marshall rennet test, 130.

Measuring fat column in testing
cream, 83; in testing milk, 35.

Mercury, calibration with, 47; clean-
ing, 48.

Metric and customary systems of
weights and measures, compari-
son of, 259.

Milk, acidity of, 108; adulteration
of, 101; amphoteric 'reaction of,
108; ash, composition of, 19; boiled,
detection of, 227; chemical analy-
sis of, 204; cholesterin in, 19; citric
acid in, 19; colostrum, 19; compo-
sition of, 11; table showing com-
position of, 233; composite samp-
ling of, 148; condensed, 22, 90, 233;
correction table for specific grav-
ity of, 237; detection of preserva-
tives in, 124, 228; determination of
acidity, 120, 213; of ash, 212; of
casein and albumen, 209, 211; of
fat, 208; of milk sugar, 212; of spe-
cific gravity, 204; of water, 207, 208;
fat available for butter in differ-
ent grades of, 182; from cows in
heat, 102; from sick cows, 102; from
single cows, sampling of, 139; vari-
ations in, 131; frozen, sampling of,
27; gases, 19; hypoxanthin, 19; lac-
tochrome, 19; lecithin, 19; legal
standards, 102, 234; microscopic
impurities, 228; mineral compo-
nents, 18; partially churned, samp-
ling of, 24; quality of, influence of
food, 145; of heavy grain feeding,
143; of pasture, 145; method of im-
proving, 146; sampling, 23; scales,
139; serum, 11; skimming, 156;
solids, 11; calculation of, 99; spe-
cific gravity of, 103; souring of, 16;
sour, sampling of, 25; standards,
102, 234; sugar, 16; testing purity
of, 125; urea, 19; water, 12; water-
ing of, 106; watering and skim-

. ming, 106.

Milk test, a practical need of, 1; re-
quirements of, 6; bottle, use of, in
testing cream, 80; Russian, 71.

Index.

267

Milk tests, Beimling (Leffmann
and Beam) 5; Cochran,5; DeLaval
butyrometer, 8; Failyer and Wil-
lard, 5; Fjord, 9; foreign, 7; Ger-
ber acid-butyrometer, 7; introduc-
tion of, 4; lactocrite, 5, 8; Leiber-
mann, 5; Nahm, 5; Parson, 5; Pat-
rick (Iowa station test), 5; re-
fractometer, 10; Rose-Gottlieb, 5;
Schmied, 5; Short, 4; Thorner, 5.

Milk products, composition of, 19.

Monrad rennet test, the, 129.

Milk testing, 29; on the farm, 181.

N. Y. board of health lactometer,
96; degrees corresponding to Q,ue-
venne lactometer degrees, 236.

Nans modification of test bottle
calibrator, 52.

Nitric acid test for adulteration of
milk, 224.

Non-fatty milk solids, 11.

Normal solutions, 110.

" No-tin " test, 60.

Nuclein, 15.

Oil-test churn, 2, 166.

Ohlsson test bottle, 87.

Oleomargarine, detection of, 219;
cheese, detection of, 223.

One-third sampling pipette, use of,
153.

Organization of co-operative cream-
eries and cheese factories, sugges-
tions concerning, 260.

Overrun, 179; calculation of, 183;
factors influencing, 179; table, 186,
255.

Parson's test, 5.

Pasteurized milk or cream, detec-
tion of, 226.

Pasture, influence of, on quality of
milk, 145.

Patrick's test, 5.

Patron's dilemma, a, 161.

Percentages, average, methods of
calculation, 160; fallacy of averag-
ing, 159.

Phenol phtalein, 111.

Physician's centrifuge, use of, in
milk testing, 73.

Pipettes, 44, 54; proper construction
of points, 45; proper method of
emptying, 31.

Potassium bi-chromate, 156.

Power testers, 61.

Preservaline, 124, 220; detection of,
in milk, 124.

Preservatives, for composite sam-
ples, 156; in milk, detection of, 124,
220.

Primost, 14.

Process butter, detection of, 222.

Proteose, 15.

Quevenne lactometer, the, 93; de-
grees corresponding to scale of N.
Y. board of health lactometer, 96,
236.

Recknagel's phenomenon, 98.

Refractometer, 10.

Reichert number, 221.

Reichert-Wollny method, 220.

Relative-value tables, 196, 249.

Rennet tests, 129.

Reservoir for water in Babcock

test, 71.

Rose-Gottlieb method, 5.
Russian milk test, the, 71.

Salicylic acid, in milk, detection of,
230.

Salt estimation in butter, 218.

Sampling cheese, 89, milk, 23, 29;
milk from single cows, 139.

Sampling tube, for cream, 171; Sco-
vell, 151; equity, 153.

Schmied method, the, 5.

Scovell sampling tube, 151.

Serum solids, 11.

Short's test, 4.

Siegf eld's modification of Babcock's
test, 73.

Sinking fund, 195.

Separator cream, 20.

Skimming of milk, detection of,
106.

Skim milk, 20; Babcock test for, 85;
chemical analysis of, 213; compo-
sition of, 233; test bottles, 87. 88.

Solids not fat, 11; formulas for cal-
culating, 100; tables showing, cor-

268

Testing Milk and Its Products.

responding to 0-6 per cent, fat and
26-36 lactometer degrees, 238.

Sour milk, sampling of, 26.

Space system, the, 165.

Specific gravity, 93; cylinders, 94, 97;
influence of temperature, 95; of
butter fat, determination of, 220;
of butter milk, 214; of condensed
milk, 215; of milk, 204, 206; of
milk solids, 103; of sour milk, 214;
temperature correction table, 237.

Speed required for complete sepa-
ration of fat, 56.

Spillman's cylinder, 120.

Standard measure for calibrating
test bottles, 52.

Starch in cream, 228.

Steam turbine testers, 61, 62.

Sulfuric acid, 63; table showing
strength of, 65; testing strength
of, 64.

Sweetened condensed milk, 91.

Swedish acid bottles, 47.

Swedish acid tester, 66.

Tank for cleaning test bottles, 43.

Temperature of turbine testers, 62;
of fat when tests are read, 36.

Test bottles, 31, 38; apparatus for
cleaning, 42; bulb-necked cream,
78; calibration, 53; cleaning, 40;
cream, 78; double-necked, 87;
draining-rack for, 41; marking, 39;
for cream testing, 78; for skim
milk testing, 87; rack for use in
creameries and cheese factories,
154; tank for cleaning, 43; Winton
cream, 79.

Testers, 54; ascertaining speed of, 58;
hand, 59; power, 61.

Testing cows, number of tests re-
quired during a period of lacta-
tion, 136.

Testing milk and its products, 1; on
the farm, 131.

Test sample, size of, 142.

Thermometer scales, comparison
of, 257.

Thermometer in frame of turbine
testers, 63.

Thorner's method, 5.

Total solids in milk, 11; determina-
tion of, 208.

Trowbridge method of calibration,
50.

Turbine testers, 61, 62, 63.

Variation in composition of butter,

177.
Variation in quality of milk, 131,

143; causes of, 135; latitude of, 102;

ranges in, 143.
Volatile acids, 220.

Wagner skim milk bottle, 88.

Waste acid jar, 41.

Water, calibration with, 49; deter-
mination of, in butter, 216; in
cheese, 222; in milk, 207, 208; oil-
stove for heating, 34; reservoir for,
71; to be used in the Babcock
test, 71.

Watering of milk, detection of, 106.

Watering and skimming of milk,
detection of, 106.

Weights and measures, comparison
of metric and customary, 257.

Westphal balance, 206.

Whey, 22; Babcock test for, 89;
chemical analysis of, 213; compo-
sition of, 233.

Winton cream bottle, the, 79.

Wisconsin creamery butter, sum-
mary of analyses, 178.

Wisconsin curd test, the improved,
125.

Wollny's refractometer, 10.

World's Fair breed tests, composi-
tion of butter from, 177; variation
in quality of milk, 142.

Yield of butter, calculation of, 176;
and butter fat test, 176; from milk
of different richness, 182; tablb
showing, from 1 to 10,000 Ibs. of
milk, testing 3 to 5.35 per cent.,
253.

Yield of cheese, calculation of; 187;
relation between, and quality of
milk, 187; table showing, corres-
ponding to 2.5 to 6 per cent, of fat,
with lactometer readings of 26 to
36,1256.

300,000

MACHINES IN USE

Ten Times all other makes com
bined .......

The Standard of all that's best in
Dairying in every country in the
world .......

That's the history of the

De Laval

Cream

Separators

Send for new
" 20th Century" catalogue

*

The DC Laval Separator Co,

General Offices:

74 Cortlandt St, NEW YOBK

Randolph & Canal Sts., Chicago 327 Commissioners St., Montreal
1102 Arch St., Philadelphia 75-77 York St., Toronto

103-105 Mission St., San Francisco 248 McDermot Ave., Winnipeg

f""1" .............. Illlllll ..... II ..... I ......... I ..... n, „ ...... IMIIIIIIIIIIIIIIIIIIIIHII ..... HI

testers]

FACILE

IRONFRAMEMAGHINES

Most Accurately
Built and Best
Known Machines
on the Market

-FOR BOTH-

Steam and Hand Power

"B.4W."

Potassium Bi-
chromate and
Corrosive Subli-
mate Tablets for
preserving milk
samples

Scales for

Weighing Solids

for Testing

D. H. BURRE,LL «5 CO.,

LITTLE. FALLS, NE.W YORK.

....Cheese Factory and Creamery Apparatus and Supplies.., f

IIIIIIIIIIIIIIIIIIIMIMI ,,,,,),, iimiiii.MmM.iiuiiii.ii,, ,,, inn iiiiiiiiiiiiuiir

t The Improved U. S. Cream Separator *

f AMD

f The Agos Cast Iron Babcock Tester

ARE THE LEADERS.

At the Pan-American Model Dairy, the U. S.
Separator demonstrated its superior skimming
qualities very conclusively.

Although other separators were invited, yet
only one make entered in competition with the U. S.,
and this '-' would-be" competitor left twenty-five
per cent, more butter-fat in the skim milk and eleven
per cent, more in the buttermilk than the U. S., the
average test of the skim milk from the U. S., as re-
ported by the Superintendent, being .0138.

The U. S. Separator does the same superior
work at the Experiment Stations and Dairies, as
witness the following statements:

Missouri College of Agriculture,

Columbia, Mo., Oct. 30, 1901.

The machine (U. S.) did excellent work, and, as a rule, I be-
lieve it skimmed a little closer than the others we had in use.
The record was invariably .02 of one per cent, or lower, some-
times a mere trace of fat in the skim milk.

C. L. WILLOUGHBY, Instructor.

Professor Spillman, Director Washington Experiment Station,
in Ranch and Range. Seattle, August 15, 1901, reports the follow-
ing tests of skim milk from dairymen using the U. S. Separator: —
.00, .00, .01, .01, .04.

As to the value of the Agos Testers, we only
need to call attention to the following letter from
Professor Farrington, of the Wisconsin Dairy
School, where they are used more than any other
make.

Wisconsin Agricultural Experiment Station,

Madison, Wis., Jan. 24, 1902.

The Turbine and Hand Agos Babcock Milk Testers, which you
make, have been used in our Dairy School for several years. We
have been well pleased with them, as they runsmoothly and wear
well. I am glad to recommend them to anyone wanting a Bab-
cock Milk Tester.

E. H. FARRINGTON, (Prof. Dairy Husbandry.)

We make different sizes and styles to suit the needs of the purchaser.
Our new Style B. Agos Tester is made specially to take long neck A
cream bottles. Write for special descriptive catalogues.

VERMONT FARM MACHINE CO,, Bellows Falls, Vermont, t

CHR. HANSEN'S LACTIC FERMENT

improves the flavor, uniformity and 1
keeping quality of butter and cheese. L

THE -MARSCHALL- RENNET- TEST fe

E
E

is indispensible for testing the milk
in the Cheese Vat.

We are the manufacturers of Chr. Hanson's
Danish Kennet Extract, Cheese Color, Rennet
Tablets and Cheese Color Tablets, Danish But-
ter Color and Columbian Butter Color.

Write us for descrip-
tive circulars

GHR. HANSEN'S
LABORATORY

LITTLE FALLS, N.Y

The Mower-Harwood

Company...Cedar Rapids, Iowa

. . . DEALERS IN ...

CRE,AME,RY MACHINERY AND
SUPPLIES, BOILERS, E,NGINES,
ENGINEERS' SUPPLIES, E/TC.

COMPLETE OUTFITS A SPECIALTY
A Catalogue Sent for the Asking NOT IN THE TRUST

General Western Agents for Manufacturers of

Reid Hand and Power Separators Hill's Automatic Skim

Reid Pasteurizers and Coolers Milk Distributor

Facile Improved Hand Emily's Perfection Starter

and Power Testers Can

Dairy Queen Combined Churn and Butter Workers
Troemner's Cream Weighing Scale

ACCURATE

GLASSWARE

We are the inventors and sole proprietors of the

"NH" TESTING APPARATUS

(referred to in this book) used in
testing all our Milk and Cream
Bottles and Russian Tubes.

We give a guarantee with each piece of
glassware we send out. If you wish perfect
accuracy and thorough satisfaction in every
detail, write us.

LOUIS F. NAFIS & CO.

120-122 Randolph St., CHICAGO

SCIENTIFIC INSTRUMENTS AND DAIRY GLASSWARE

A

Cream Bottle

CREAM-WEIGHING SCALE'

PRICE, $10.00

For use in Connection
'with the Babcock Test

«?HIS SCALE is especially designed
*-* for very accurate weighing of
cream. All bearings are agate; plates
are porcelain; base and under connec-
tions are galvanized, making a rust-
proof scale. It has a side bar in front to
balance the test bottle, and is provided
with the necessary weights. Base of
scale 10% in. long; porcelain plates, Sin.
square. Manufactured by
710 Market St., Philadelphia, Pa. HENRY TROEMNER

| Star Sanitary Dairy Apparatus

Is in use at a large number of the Agricultural Colleges
and Sanitary Institutions of this country, among
them the University of Wisconsin. In the construc-
tion of this apparatus is combined Sanitary, Scientific
and Practical features together with the best material
and workmanship. No machine is put on the market
that cannot be thoroughly cleaned and that has not
been tested in every way. In our 1902 catalogue you
will find many new features and attractive pi-ices.
Send for it.

STAR MILK COOLER CO., Haddonfield, N. J.

THE WAGNEB GLASS WORKS 8

of NEW YOBK CITY

are a most reliable firm where to obtain accurate
Glassware. They have made numerous inventions
and improvements on Apparatus and Instruments
for testing Milk and its products. Amongst their

latest inventions may be , „

mentioned a Test Bottle
with INDELIBLE GRADU-
ATION. The graduation
does not require any re-
blackening; it will always
remain jet black no mat-
ter what acids or chem-
icals are used for cleaning
the test bottles after a
test has been made. This
last improvement fills a
long-felt want.

The Wagner
Glass Works

New York

ooooooooooocco:

9 *** 333 444 444 444 444 444 444 444 444 444 444

RIGHT
NOW!

We pride ourselves up-
on the quality we put
into our complete line of

Butter Workers

Churns

Butter Printers
Babcock Testers

Skimmed Milk Weigh-
ers

Cheese Vats

Curd Mills

Cheese Presses

Milk Vats
Cream Cans, Etc.

Write for descriptive
circulars

The Tubular

I
I

Dairy
Separators

Excel all
Competitors for

CLEAN SKIMMING, EASE
Or OPERATION, EASE
OE CLEAN I NO, CONVEN-
IENCE AND BEAUTY.,

They are altogether different
from other separators; a dif-
ference which you will ap-
preciate. A small, light bowl,
fed from the bottom. A low-
down supply can that saves
lifting heavy milk cans. It's
just the separator you want.

Write for free descriptive
catalogue.

Che Sharpies Co.

28, 30 and 32 Canal St.
CHICAGO, ILL.

fi' BOOKS ""!

'' =^=^= 1

The following baoks on dairying and related topics T

will be sent, postage prepaid, upon receipt of the price i

given. ^

Woll, Handbook for Farmers and Dairymen. Second ed.,

New York, 1900, 437 pp $150 £

Grotenfelt-Woll. Principles of Modern Dairy Practice.

Third ed., New York, 1899, 286 pp $2 00

Wing, Milk and its Products. Third ed., New York, 1900,

311 pp $1 00

Fleischmann, The Book of the Dairy. London and New

York, 1896, 344 pp $4 00

Richmond, Dairy Chemistry. London and Philadelphia,

1900, 384 pp $4 50

Snyder, Chemistry of Dairying. Easton, Pa., 1897, 157 pp. .. $1 50

Decker, Cheese Making. Columbus, O., 1900, 192 PP $1 75

Russell, Dairy Bacteriology. Fifth ed., Madison, Wis., 1902.

215 pp $1 00

Gurler, American Dairying. Chicago, 1894, 2.67 pp $1 00

Monrad. A B C in Buttermaking. Winnetka, 111., 1900,68pp. 50

Monrad, A B C in Cheesemaking. Winnetka, 111., 1900, 68pp. 50

Vye, Creamery Accounting. St. Anthony Park, Minn., 1900. $100

Bailey, Principles of Agriculture. New York, 1901, 300 pp. 11 25

Storer, Agriculture. Seventh ed., New York, 1897, 3 vols. $5 00
Henry, Feeds and Feeding. Fourth ed., Madison, Wis.,

1902, 657 pp $2 00

Jordan, The Feeding of Animals. New York, 1901, 450 pp. $1 25

Woll, A Book on Silage. Revised ed., Chicago, 1901,234pp. $1 00
Peer, Soiling, Ensilage, and Stable Construction. New

York, 1900, 247 pp $1 00

Shaw, The Study of Breeds. New York, 1901; 371 pp $1 50

Craig, Judging Live Stock. Seconded.. Des Moines, la.,

1901, 193 pp i $2 00

King, The Soil. New York, 1900, 303 pp $1 00

W King, The Physics of Agriculture. Second ed., Madison,

Wis., 1901, 604 pp , $1 75

Hopkins, Veterinary Elements. Second ed., 1901, 286 pp. .. $1 50
Goff, Principles of Plant Culture. Second ed., Madison,

Wis., 1899, 276 pp f 1 25

Adams, The Modern Farmer. San Francisco, Cal., 1899,

662 pp $5 00

k

MENDOTA BOOK CO.

MADISON?WIS.

YB 16413