THE LACTOMETER-ITS
UTILITY AND
RELIABILITY. By CHARLESE. XUNSELL, Ph. D.* After using the lactometer constantly for six years (1880 to 1885), an ex-milk inspector wishes to demonstrate its value, utility and reliability as a detector of adulteration, as well as to refute its alleged errors. To obtain scientific accuracy with the lactometer, it is necessary to have an instrument which is absolutely correct, that is, exact from 90 to 110 degrees, and not over one degree in error a t other points ; and the examiner must be an expert, who uses all the precautions that would be needed in employing other sensitive in strumonts, for the lactometer is the most delicate hydrometer in ordinary use, each degree being less than one-twentieth of a degree Baum6, its modulus being the highest, 3548&, while that of the Baume scale is 140. The compiler was extremely prejudiced against the lactometer when he commenced his inspections, for if analysis were useless, i t would be unnecessary to employ a chemist as an inspector ; therefore, for two years, no complaint was made by him unless the sample had been previously analyzed ; afterwards the analysis was dispensed with unless the lactometer stood above 95 degrees, as in every case the analysis showed from three to ten per cent. more added water than the lactometric indication. Whenever milk was found between 95 and 102 degrees, an attempt was made to discover its source, b u t in no instance was a cow found giving milk below 101 [degrees; of course, in this search strippers (cows nearly dry) were avoided, as the small quantities of milk given by them would have b u t little influence 4
Rcad before the American Chemical Society, June, 1888.
THE LACTOMETER.
123
on the specific gravity, when mixed with that of regular milkers in a forty quart can ; the sule of the milk from a cow that is nearly dry should be prohibited, the same as that of a cow shortly after calving, on account of its liability to contain pus and to be otherwise contaminated. The milk should be taken a t the regular milking time, as it is very easy to obtain samples a t irrcgular times which will have specific gravities as low as 1.0226. (78"); and the specific gravity immediately after milking and cooling is lessened by absorption of air. If the cream has risen it is difficult to mix the sample again ; and a sample taken from the top of a bottle or can is liable to contain an undue amount of fat. Therefore, if the specific gravity of a cow's milk is below 1.020 ; either the milk is abnormal, that is, from a diseased cow, or from one which is nearly dry or has lately calved ; or the sample tested is not a fair average of all the milk that could be obtained from the cow a t her regular time of milking ; or the sample has bee11 tampered with ; or is full of air ; or the lactometer used is incorrect ; or the temperature is above 60" Fahr. When the New York City Board of Health commenced its crnsade against the sale of adulterated milk in 1875, t h e citizens were paying over $10,000 daily for water sold as milk. During 1575, $2,300 ; 1876, $2,900 ; 1877, $5,100 ; 1878, $1,73G; and 1870, $527 were paid into the City Treasury as fines by milk dealers. I n 1880, a systematic store inspection was made throughout the city, which resulted in a reduction of the instances where the ltlctometric readings were below 100 degrees from one in threc to less than one in twenty, the average for the year being eleven per cent., the average specific gravity in about one-fourth of the stores in the city being 1.0308 or 106 degrees ; the fines for 1880 were $4,518. I n 1881, the store inspections were continued with weekly early morning inspections to examine the milk retailed from the wagons, and night inspections to test that brought to the city by the railroads and across the ferries ; these night inspections showed
1?4
THE LACTOMETER.
that dealers had ceased to deliver watered milk to the stores or consnmem, or to receive it from the farmers, as the dealer was constantly watching the milk sent by the farmer in order to refuse payment for it if watered. As the lactometer caused the detection of watered milk, the dealers formed a combination with the creameries for the sale of skimmed m i l k ; during the Summer of 1881, these creameries were visited under tlie direction of the New P o r k State Board of Health, and although n o complaints were made against them directly, the dealers, whoin they supplied, were watched and the milk was inspected a t the ferries: from five to ten thousand quarts of skimmed milk were destroyed a t each night inspection until the traffic was stopped and the dealers fined ; these fines amounted to 811,657 i n 1881 ; $9,058 in 1882 ; $2,265 in 1883 ; $3,101 in 1884 ; and $2,040 in 1885. The total fines collected from dealers for the sale of adulterated milk from 1875 to 1885 amounted to $45,202 ; besides nearly fifty imprisoiinients for terms of from ten days to three months. The combination of dealers and creamerymen resulted in a Milk Trust, known as tlie New York Milk Exchange, limited ; nine of the thirteen original directors of this exchange have been arrested for selling adulterated milk, and aided by the best lawyers and most depraved chemists they hired a man to act as the defendant in a test case with regard to the lawfulness of the sale of skimmed milk ; the trial resulted in his conviction a t General Sessions and his payment of a fine of $150. This exchange has since succeeded in having the aforesaid defendant appointed as an expert on the New York State Dairy Commission, and the consequence is that the farmers can obtain no better price for milk containing over 3 per cent. of fat than these creameries do for partially skimmed milk. The lactometer, or centesimal galactometer, was invented by Dinocourt ; for descriptions of this and other lactometers, galactometers, lactodensimeters, milk testers, and milk weighers, see Dr. H. A. Mott’s article in the Americait Chemist, April, 1877, Vol. VII., p. 369. The compiler was only employed as an inspector, and as such was kept busy examining the milk sold by his proportion of the
THE LACTOMETER.
125
2,000 milk dealers and 6,000 stores in New York City, and did not investigate methods of analyzing milk, but used the method of Wanklyn, as improved by Dr. Waller, and published in Cairn's Quantitative Analysis ; what suggestions he would have made with regard to the analysis have been anticipated by Dr. W.H. Kent, and published in this journal (Vol. IX, p. 132, and Vol, S, p. 32.) Thetometers as obtained from the maker should be tested a t 60" Fehr.; this is done either by comparing with a standard lttctometer which is known to be absolutely correct (this is the best method when only one instrument is to be examined), or by means of standard solutions ; these solutions are made of salt or dilute sulphuric acid. A 3 per cent. solution of sodium chloride has a specific gravity of 1.0217 ( 7 5 O ) ; a 4 psr cent. 1.0% (100') ; a n d a 5 per cent. 1.036 (122O) ; these solutions, and others a t 90" and l l O o , should be tested with a specific gravity bottle a t GO" Fahr. With sulphuric acid a three per cent. solution has a specific gravity of 1.019 ( G G " ) ; a four per cent, 1.035G ( 8 8 " ) ; tl five percent, 1.033 (111'). The fault with the salt solutions is that they vary from evaporation ; the dilute sulphuric acid solutions are more constant, still they should be tested occasionally. It is necessary to allow the lactometer to descend into the milk slowly, as the milk which remains on the portion of the stem above the surface of the sample being tested, when the entire fitem is dipped, would lower the reading about two degrees ; the baniple should not be shaken any more than is necessary to mix any cream which may have risen, as it will absorb air ; and the foam on the surface should be removed, as it makes i t difficult to read the scale. When a cow is milked, it is necessary to take the entire quantity given a t the regular time of milking, as the first portions of the milk contain the most casein and sugar, and the last the most cream ; milk taken from a cow whose regular yield stands a t over 1 0 5 O will give milk standing below SO" if the cow is retnilked shortly after her regular time ; the milk should be allowed to
136
THE LACTOMETER.
stand for some time after it is drawn from the cow, and cooled before testing, so that the air absorbed during milking will be allowed to escape. For accurate tests the sample should be cooled (if above 60" Fahr.) by placing the bottle or cylinder in cold water or packing with ice ; or if below GO" Fahr. by setting in warn] water, rubbing the cylinder with the hand, or placing in a warm room. A difference in temperature of from 2 3 to 3* degrees Fahrenheit will cause a variation of one lactometric degree, different samples of milk having different coEfficients of expansion ; 3 degrees is t h e usual average, and is approximately correct from 40" to 70" Fahr. Beyond these temperatures its calculation is uncertain, particularly if the temperature is near freezing or so high t h a t the milk is liable to sour ; when once frozen, the constituents of t h e milk appear to separate, and after thawing the specific gravity is different When the contents of a can of milk are frozen, the water freezes first, pushing the cream and casein towards the center, in very cold weather forming an inner core of cream ; while, after melting, the ice around the exterior has a specific grtivity sometimes as low as 1.008 ; a common trick of milk dealers being to pour out the core, and then scrape out the ice, sometimes mixing i t with snow or iee. The consistence or thickness of milk can be easily determined by allowing i t to run off of the lactometer and noting its appearance over the black background of the shot in the lower bulb ; this consistence is an important test, as with the opacity due to the cream, the color and taste, the examiner, with some practice, will be able t o determine within one-half of one per cent. how much fat the sample contains when below three per cent., and approximately above that a m o u n t ; if t h e milk contains less than one-half of one per cent. of fat i t has a mother of pearl opalescence, which caxi easily be seen even by laniplight, i t also looks blue and tastes very sweet ; if less than one per cent., the opal lustre is still apparent, the color blueish, and tastes sweetish ; if under one and one-half per cent., t h e milk appears like glue, color neither blueish nor yellow, and tastes
.
THE LACTOUETER.
127
flat ; if below two per cent., i t becomes more opaque, slightly yellow, and tastes more milky and not so sweet ; above two and onehalf per cent., it is opaque, yellow, niid the cream can be tasted in proportion to the amonnt contained. When the cows are kept confined in stables and fed on distillery swill, or are in an unhealthy condition and fed exclusively on decayed brewers’ grains, the odor of the milk will betray the fact ; but the odor of milk from cows fed on brewers’ grains mixed with other feed is not characteristic, if the milk is thoroughly cooled immediately after milking, so as to remove the animal heat. The principal complaint against the lactometer is t h a t ti person who never saw a sample of milk might be deceived by testing a liquid that had about the same specific gravity-a salted solution of white glue, for instance-if he made the test, as he might of a n unknown substance, from a book description. As it is necessary to add a solution of a t least four per cent. of salt to milk in ordcr not to reduce its specific gravity, i t can always be detected by its brackish taste ; and the addition of b u r n t sugar or annatto will not conceal the opalescence of skimmed milk or the thinness of watered milk. The following formula for a compound for circumventing t h e lactometer was devised by the chemist, who was employed by t h e Hester street coalition of dishonest dealers : (1) One gallon of water, (3) Three ounces of sugar, (lg) One and a half ounces of salt, and a little caramel ; This to be added to (4) Four gallons of milk. This gives a fluid which standd a t 99 degrees on the lactometer a t 60’ Fahr., and shows on analysis : Water, 89.06%; fat, 2.95% ; casein and sugar, &SO$; and salts, 1.19%; sodium chloride, 0.42$. The salt can be easily detected by its brackish taste, and the dealer who offered it for sale did the State one month’s service besides paying b fine. Usually the addition of water alone was sufficient for milk adulterators of the olden time, as the easiest and most convenient;
they tlieii ran the risk of detection, coiisidering that the fine-if they were caught-had been paid many times by the consumer; now, the adnlteration is mostly performed a t crciameries, where / ruth inilk from the farmers is changed into p i w e inilk for t h e city, by the addition of from twenty to fifty per cent. of skimmed Illilk. Objectioii has been made t o the u s e of the lactometer that it is nureliable, because, being an even scale hydrometer, the degrees are not accnrately graduated ; this error of construction IS T ery m a l l on ncconnt of the slight range of specific gravity which it records, the greatest error being a t the 50 degree mark, where the error is .;14 of one degree, or .O.?fj of an inch 011 the regular size of lactometer, whose scale from 0' to 100' is 3 2 inches. See Drs. TYdler and Hathaway's paper on the Modulus of IIydrorneters i n the School of Mines Quarterly, 1.01. ]*I., 13. 153 (January, 1835). To f i i i c l the error of a lactometric degree from the true position of tlic same, according t o the laws of graduation of hydrometers by the specific gravity. = 1701nme of lactometer immersed when floating iii water, that IS, volume of water of the same weight as lactometer. ly4, i r 5 ,etc., T l o=Volumes of lctctometer imI-,,\'. mersed when floating in solutions of gravities corresponding to IO', ?0 , , 40 , .io'. etc., 100' respectively, assuming that 10- = 1.+10X0.000'!9 ; 2u =1.+20x0.000'!9, etc. ].=Length of stem from 0- to 10(J". r.=.%rea of cross section, assnmed to be uniform throughout. I,.=Tmgth of lactometer assuming it to be all stem ; then Y=Lr. (1) Kow for a solution of gravity equal to 1.029 ; we have the volume of liquids of same weight as the lactometer 1- and ITlo. These are to each other inversely as the specific gravities of the solntions, or v : v, =l.029 : 1 l-lo=lu\g=T-. x0.9';1817. (2) Subtracting each member from ; \7-1T, ,=0.028153 1- (3) Or the stem of the lactometer between 0" and 100" is 0.028183 of the volume of the whole lactometer.
T H E LACTOMETER.
129
Then lr=volunie of the stem between 0"and loo", and Ir= 0.028183 Lr from ( l ) , or dividing by r, I= 0.028183 L, or L=,,&,,l. (4) If the value of 1 is 38 (=3.625) inches, L 1 2 8 . 6 9 3 6 3 8 inches (or 10 feet 83 inches nearly). If 1 is 20 centimeters, L='709.647659 centimeters. If 1 is one meter, L=35.482383 meters. For solution of gravity of 50", specific gravity 1.0145. By t h e tame reasoning which gives us equat'ion (2), we obtain V : V6=1.0145 : 1; V , = V , g k = V X 0.985707. (51, and V--V,=0.014203V=O.O1~903Lr. (6) Volume of stem from 0" to 5Oo=1,r=3.014203Lr, or dividing through by r 1,=O. 014-2931; (7) If the 50" mark is placed just half way between 0" and 100"; i t is placed a t 1 below the 0" mark or from equation (4) a t 4 1=0.01400PL, then 16-+ i+o. 01.1293-0. oi.iooqrJ=o. O O O ~ O ~ L (8) or when placed half way between 0" and looo, it is by that amount above its true position, the measurement being made from t h e 0" mark, and I ) 3 1. Assuming the value for L obtained from (4), ( 8 ) gives; lo-+ 1=0.'3501'77 inches (9) l0=dab of 3.625=0.0:3G*25 inch, and the 50" mark is out of place by +:#+#"=$" nearly. If L=700.6476,50 centimeters, 1,- 3 1=0.143832 centimeters If L=35.488383 meters, 1,L0.7142GO centimeters. For solutions of other gravities, corresponding to loo, 90°, 30", 40°, etc.=1.0329, 1.0058, 1.0087, 1.0116, etc. v : v,=1.0030 : 1 ; vT.&~g=0'9971OYV V-V, =0.00:!89'JV=O. 002SO'?Lr=1* r dividing by r and substituting va!ue of L L128.623638 inches ; I1=0.3719Y1 inch, & 1=0.3625 inch ; difference=0.009481 inch too high (11 )& 1) L709.64'7659 centimeters ; diberence=0.052017 centimeters L35.48'7383 meters ; difference=0.9GOOYG centimeters
+
+
130
THE LACTOMETER.
For 90"=specific gravity of 1,0261 ; IT: IT,=1.02Gl : 1 ; \T--V,=0.'7543G\7, 1,=3.271680 inches ; 1$ 1=3.'?695 inches, difference=0.009180 inch t o o high (1 I$ 1) For l"=specific gravity of 1.00029 ; V--T-,=O.O00072SV ; difference=0.0000103
,>
inches too high. For 99"=specific gravity of 1.02871 ; 1, ,=3.58074 inches ; difference=0.00009 inches too high. Table showing difference between actual positions and proper positions for marks indicating lo", 20°, etc., respectively, measured from 0 mark.
-
'
Lactometric Degree ometei.
1
IEven Even Scale Re c i prroo c a li o tip )iffarciice o f ' 1.029 divide Reciprocals by 100 aril md 1.000000. multiplikd b, 10, 20, etc.
__
10" 20" 30" 40" 50" 60" 70" SO" 90"
100"
lloo 120"
~
Crror ol Eve Scale io dec mala of tt entire lengt of Lactom rer
Crror reduced to centimeters on a meter L -z
.000073 .000130 ,000170 .000194 .000201 .000193 .000168 .000128 ,0000$1 .000000 .000087 .000189
.86008G .4G1271 .GO3555 .G8'7649 .7142GO .683391 .596104 .452755 * 253344
55.482983
meters.
I
1,0029 .997108 1.00% .994233 1.0087 .991375 1.0116 .988533 1.0145 ,985'707 1.0174 .!I82808 1.0203 .980104 1.0232 .977326 1.0261 ,0745G4 1.0290 .971817 1.0319 .96908G 1.0348 .066370
.002892 ,005767 .OOY625 ,011467 .014293 .017102 .Ol98DG .022G74 .025436 .028153 .030914 .033630
.002818 .005637 ,008455 .011273 .014002 .016910 .0 1 9 ' 28 .022546 .025365 .028183 .031001 0 33819
.
.oooooo .309406 .G72391
131
T H E LbCT03IETER.
ERROR OF
THE
DEGREE
EACH DEGREE IN
LACTOMETER FOR
DISTANCE FROM
xr 0" IS
Degree
___ 1 2 3
4 5 6 Iy
8 9 10 11 12 13 14 15 16 17
15 19 20 21 22 23 24 25 26 27 28 99 30
-
Centimeters. Degree
2.056 3.054 4.11 5.13 G.1G 7.13
I 32 1
1
8.20 9.23 10.3'30
11.95 12.30 13.32 14.34 15.33 16.38
33
34 35
3G 37 3s 39
31.G1 32.G2 33.G3
34.64 35.65
1
X.66
37.G6 3S.G;
39.GS
61 69 G3 G4 G5 GG G7 GY GO
40
41
I
42 43
I 44
45
1 46
19.44 49 20.4G1 1 50 21.48 51 52 22.50 53 23.52 24.54 I 51 25.55 1 55 2G.5G 5G 27.57 28.55 29.59 30. GO3 ~
42.69 43.69 44.70 45.70 46.70 47.70 4s.71
72 73 74 I 7.5 7G 77
49.71
79
55.705
S5
56.703
SG
I
7s
1
' ~
S7 5S.694 ss 39.GS9 SO GO.GS:; 90 I I
1i
CENTIMETERS ;
0" TO 100" B E I K G OXE JIETER. LENGTH OF 1.028 CENTIMETERS, AT 100" .98 CENTIJIETEHS.
57.GDS
:entimetere.
G1.GS 62.137 G3.M
1
Degree
91 92 93
Centimeters,
91.23 92.20 93.15 94.1G 95.135 9G. 108 97.0S3 95.05 99.02 100.OG 100.97 101. !)4 102.91 103. ss
104.55 105.83 106.';9 107.7(j 10s.73 109. G91 ll0.CjS 111.G5 ll?.G9 113.59 111.53 115.51 llG.46 117.41 113.37 119. 33
I
.
.
.
.
.
TO M E T E R S . Board
of Used
IO0
*=1.0 2 9 I O Oo=
by
Milkmen.
1.03 4 I O Oo= 1.038 10 Oo= 1.080
i
uy
JJACTOUETRIC S T A N D I N G S AT 60' FAIIR.-~UITTING SAMPLES SKIXMED MILK. Lactomet,et.
1
1880.
---
-__
1
1881.
1
___
_--
1
__1
---
--1
--i 1 1
---
2
1
56
5 1
--1
11 1;
4
45 30 18
---I I
!!!~ -__
2 9 6 10 2 15 10 22 40 25 21 64 66 67 61 80 87 102 116 122 126 119 94 84
---I
I
__-----
1 2 2 2 9
1882.
_ _ i-
_--
-_-
___
4 3 3 6 13 6 43 20 37 56 61
75 108 91 114 111 89 101 77 32 25 8
2 1 1 1 1 1 1 1 3 1 1 3 3 4 4
4 8
---
--1 1 1
OF
5 5
2 3
41
2 4
- - 3-1
5 3 14 13 18 18 32 37 47 90 97 125 143 141 177 161 158 121 114 98 67 49 19
I! 4 9 14 13 17 14 19 36 51 76 51 92 130 159 145 149 108 135 116 53 31 9
Iy
i ----_
---
3 1
----_-_
3 2 1 1
3 6 6 15 25 24 30 34 35 59 68 94 117 201 169 237 208 173 218 192 133
110 16 6
---I -_-----
1 3 3 10 24 21 34 22 35 50 48 85 118 160 214 210 255 134 227 178 129 99 13
___
___ ___
--_ ---
--_
-_- --___
12 12 15 12 19 16 37 47 77 106 118 137 '219 239 354 406 496 632 842 926 989 1007 764 889 745 470 359 95 37 14 4 2 3
Total _ _ _ _ _ _ _ _ _ _ _ _ 1514 1116 1776 1470 2195 2078 10149 Ayerage - - - - - - - - - 106.12 107.06 106.26 107.12 107.71 107.97 107.12 No. below 100"--- 167 57 121 86 125 101 657 Percentage 11.0 5.1 6.7 5.8 5.7 48 &4
__ ____
134
THE LACTOMETER.
AXALSSIS,
.-
pL.-
i
l
k*
,
9
il
K
I
-
-a:*
k
m
-
~
5.03 ,3? 5.10 * 32 5.54 A 3
159
1ss 1 ;1 13 24s :;5
ss
1.023.’
173 349 102 193
91.1s 90.0 7
300 330 9 57 20 17 327 2;
89.88 S9.48 !IO. 94 90.5G Sd. 79 no. G G
.! 9 1(i
14 3; 12 56 31 342 32 2
*
90.92 90. 9!) 8s. 94 90. G 1
!HI.25
s
1;s 86 3.I
1
9.8 2.24 3.76 2 . (i1 2 . so 1.S3 2.71 2.!)4 3.32
91 -
....
* .4l *
.?;. .x ’
.34
;.45
.!.;:I
$9. T,L‘
3.00
7.51 7.40 ‘7.53 7.4s ‘7.29
X0.9G
89.s; 89.7 s 89.154 S9.90 90.16 39.7; S9.ljO
Other signs used in this table are as follows :
Salts included with Casein and Sugar. t Cow seen milked. $ Creamery milk. $ Cows kept in Stablee, and fed on Brewers’ Grains.
5b “4 $2 .j
__
*
:i 3
.33
21.0 20.0 1 !). 8
2 .38 25
Y;
3.75 1.2; 2 . .!?
43
. t
7.29
no.. 3s
19.0
24 61
28. :1, 19.s
* * *
1.84
99.74
*? 5.0
15 4G
13
2.15
39.37 90. 08
-_
G.06 6.47 G . 76 6.2s 6.23 6.76
40.7 39. s 33.7 32.6 23.s 24, S 24.4
, .j3 ?;
* , 60 ,
:,8
* * * * * *
-39 5G
19.0 l;:! 10.5 1
-
.
17.2 12.0 16.4 17.0 1;.0
16.3 18.4 13.1 17.0 14.0 13.6
10
--
5; “9 9 -5
20 14
10 1v
-.
-_ 21
14 13
135
THE LACTOMETER.
I
308 343 64 23 19 344 321 32 30 34s 169 22 238 2s 351 346 345 185
1s
294 15 316 328 164 317 352 65 293 223 58 290 162 147 347 6 254 240
I
94
_-
A NALYPIS
I
1.0273
__ __
-_ --
-__ 95
--
__
-_
96
--
__
__ __ __
--
__ __ __
97
__ __
-_ -_
__ __
--
__
98
__
-_ __
__
99
-----
I
I
89.72 89.54 89.22 89.18 59.13 88.92 58.53 88.32 s9.22 89.21 88.95 88.35 91-04 89.80 89.4G 89.40 89.09 89.01 88.78 88.64 58.51 88.44 89.59 89.65 89.57 89.18 89.09 89.05 88.88 88.73 88.26 89.71 89.55 89.41 89.21 89.01 90.49
2.59 2.3s 3.20 3.00 3.10 3.22 3.31 3.90 2.83 2.72 2.98 3.53 1.37 2.41 2.44 2.55 2.77 2.9G 3.3s 3.16 3.6G 3.32 1-55 2.49 2.51 2.57 3.19 2.75 3.10 3.06 3.36 1.82 2.33 2.48 2.25 2.95
.90
I
/
7.10 .59 7.47 -61 7.04 .54 7.82 *
14.6 10.2 15.8 13.1 IY r .p.r r3 * 18.4 7.27 .59 12.7 7.29 -57 12.7 7.78 * 13.4 7.95 * 11.5 7.47 .GO 10.3 7.46 . G l 10.3 8.12 * 9.8 6.98 . G 1 15.7 7.79 * 13.4 7.49 . G l 10.0 7.46 .59 10.G 7.51 .e4 9.5 7.49 .55 10.7 1?.8 7.84 * 7.61 .59 8.9 7.83 * 12.7 7.61 .G3 8.5 7.92 - 6 4 5.2 7.25 . G 1 12.7 7.31 . G 1 12.0 7.G3 .G2 8.3 7.04 .cis 14.2 7 . 5 2 ,135 9.2 7.40 .G2 ~10.9 8.21 * 8.8 7.75 -63 G.9 7.S1 .G6 5.9 7.65 .66 7.7 7.50 .61 10.0 8.54 * 5.1 7.48 .56 10.7 ,
7.88 .64
5.3
14 20
--
---
--
-_
__
6 9
__
-_ 54 20 19 15
; __ __ I-
__
__
48 1'7 16 21
__ 8 __ ---
39 22 17 25 2 67
136
T H E LACTOMETEH.
.-m'
:a
h
c
n
2
I
I _ _ _ -
350 276 298 392 295 163 89 247 1 40
146 251 208 253 100 181
8'; 83 226 123 55 299 209 245 297 246 211 331
176 212 228 36 74 191 48 99 72
89.06 68.81 88.49 88.18
2.50 2.67 1 3.19 3.26 1 89.42 2.24 89.20 1 2 . 2 2 89.01 ' 3.40 88.94 2.58 2.06 88.89 88.65 3.02 88.60 3.11 88.55 3.09 88.32 3.47 88.19 3.23 88.76 2.78 90.6G 1-30 89.61 69.14 80.05 85.89 2.92 88. YO 2.85 58.18 3.70 90.24 1.53 89.17 5.52 88.69 3.10 88.55 2 . 7 8 88.55 3.05 88.24 2.65 1.42 90.26 1.75 00.04 89.76 1.83 89.06 2.54 88.15 3.06 87.16 3.74 88.54 2 . 77 86.1s 4.55 5.38 85.45
.61 .61 .63 .61 .61 7.92 , 66 6.99 .60 7.87 ,61 9.05 * 8. 33 * 7.68 .61 7.70 .66 '7, 60 .G 1 7.96 I.62 7 , 7 8 .GX 7.41 .G:i * 65 , 64 .70 '7.83 7.91 7.69 7.95 7.73
~
n
-. .64
I
31
7 . g -7.1 8. 8 4.7
t
10.7 8.8
10.0 6.7
*
9.0 7 .2
61 ,63
9.8 8.3 7.6 8. 8 3.7 6.7
1.33
8.35 7.51 7 .GO 7.76 7.56 8.04 7.76 8.45 7.71 7 .G5
6.2 17 5.3 11 7.6 I _ _ 5.0 ! - 7 . 3 1 95 4.; 26 15.7 ' _ _
I
.55
.65 -63 .64 -66 .61 -59 r + 1. i G .67 8:40 * 8.13 .66 8.45 ,65 8.69 * 8.60 ,67 8.45 .72
$
7.6 8.8 5.2 6.6
8
st t
t
137
THE LACTOIXETER.
-ANALYPIP.
d
-
K
32 E4 %
d m "0
&:
f
s iI W
4
150 210 239 31 8 214 341 332 154 155 38 236 282 152 184 233 148 304 180 277 2 30 227 101 302 93 94 53 353 179 214 288 130 243 123 280 286 235 291
90.54 90.2 9 89.45 89.25 88.51 88.48 88.36 88-27 89.48 89.18 88.84 88. 68 88.63 88.38 88.38 88.15 as. 90 89.30 88.83 88.79 88.37 88.48 87.64 87.48 87.25 86.08 91.39 90.01 89.38 89.19 89.16 89.00 88.71 88.52 88.48 88.26 88.22
1.03 1.54 1.77 2.33 2.85 2.53 2.90 3.24 1.97 2.04 2.82 2.74 2.46 2.5s 2.68 3.29 3.41 1.06 2.40 2.18 2.69 2.75 3. 67 3. GS 3.84 4.58 1.50 I.31 2.02 2.47 2.22 2.14 2.42 2.86 3.03 2.36 2. 61
6. 3 7.81 .62 N 15P I. I I -60 7.0 8.09 69 2.5 t-15 i. 16 G6 6.5 8.05 * 59 4.0 ? 8.35 .(i5 2.9 8.07 .67 7.80 .69 5.7 5.0 7.96 .59 8.78 * 2.5 7.74 .60 7.4 8.01 ,57 4.2 8.38 .63 2 ? 8.43 G 1 ? 8.31 .63 4.9 7. 89 .67 7.97 .72 t 2.9 8.05 .69 3.1 8.05 .66 8.31 .68 2 8.14 .71 t 8.01 .76 t 7.98 .71 t 8.08 ,76 t 8.25 .70 t 9.34 * t 6.51 .GO 21.0 3 .G 8.06 .62 4.6 7.96 63 N15 7.3 .62 I . (2 4.2 7.93 .69 8.15 .7l 2 8.20 67 2 4.2 8.02 -60 5.7 7.88 .61 8.70 .68 2 8.53 e8 i
. .
.
.
.
.
i
c)
V
66 48 41 22 5 16 31
__
34 32 6 9 18 14 10
-t
35 18 27 10
t t
t t t
50 5G 33 18 26 29 19 5
--
21 13
135
THE LACTOUETER.
139
THE LACTOMETER.
I
ANALYSIS.
-m d
c
c)
-: # i P 3
34
309 312 313 255 45 59 71 242 232 285 229 151 5
250 54 168 98 60 52 158 132 109 231 25 21 121 225 128 137 75 167 306 311 259 310 215 174
87.96 87.93 87.59 87.58 87.08 84.23 89.78 89.03 88.85 88.68 88.66 88.62 88.48 88.21 87.90 87.78 87.34 86.54 85.76 91.25 89.52 89.47 89.04 88.71 88.32 88.27 87.87 87. 78 87.72 86.81 84.27 87.88 87.82 87.31 87.07 89.33 88.82
3.10 2.89 3.45 2.99 3.63 5.32 1.38 2.17 2.19 2.37 1.95 2.29 2.71 2.96 2. 78 2.01 3.32 3.58 4.34 -11 1.56 1.68 1.67 2.31 2.62 2.54 2.58 2.93 2.96 3.58 6.03 2.93 2.87 3.46 3.39 1.76 1.75
-
8.24 8.53 8.29 8.85 9.29 9.74 8.84 8.09 8.31 8.32 8.56 8.44 8.81 8.23 9.32 8.68 8.63 9.28 9.90 7.92 8.92 8.16 8.59 8.98 9-06 8.46 8.88 8.58 9.32 8.92 9.08 8.51 8.68 8.51 8.91 8.29 8.74
-
.70 .65 .67 .58
tt ti
.71
t t
*
*
.71
2.0 2.3
t t t
54 27
-65 .63 .70 .65
*
I
60
*
-63 .71 .60
* .72 * I
69
,SI0
* *
I73 69 I
* ,69 62 ,67 62 I72 63 ,62 ,69 I
I
I
E B
t t t 4.0 t
I
t t t t t t
1
t t t t
1
10 1 r,
it t t
96 48 44 44 23 12 17 14 2
1
I
t t t t
41 42
-
140
THE LACTOJIETEK.
141
THE LACTOMETER.
ANALTPIS.
- --
.-i t,
j?
g4
'4
i
5
a .
B"
a-
L
76 264 79 307 256 119 110 159 24 281 34 355 266 43 26 218 10 224 92 356 357 265
88.10 88.06 87.90 86.91 86.28 90.55 89.86 90.70 90.69 90.23 88.78 88.23 88.12 86.87 90.73 90.38 88.62 88.53 86.91 80. 65 89.46 89. 61
2.48 2. $9 2.61 3.65 4.19 -06 .71 .OS .51 .49 1.83 1.94 2.54 3.39 .18 .06 1.87 2,14 2.13 .26 .49 .55
-
.z0 tc3
11
I= I
m
be
-8.71 8.46 8.'76 8.74 8.88 8.70 8. 74 8.50 8.80 8.59 9.39 9.17 8.61 9.84 9.09 8.89 9.51 8.66 LO. 21 9.47 9.39 9.11
.71 .69 .73 *
?O
.65 .69 .69 ,72
a
r
E
0
P
0
17 c
13
t t
.6G .73
98 76 97 83 84 39 35 15
.70 e75 * 62 .66 .73
94 98 38 29 29 91 84 82
* *
.69
* * .68 *
t
142
THE LACTO3TETER.
The percentages of water added and cream removed in the preceding analyses were calculated from the standards of the States of New York and New Jersey, namely, over 9 per cent. of solids, not fat, over 3 per cent. of fat, and less than SS per cent. of water. For details with regard to the samples taken from cows which were seen milked, and the names of owners of some of the samples of adulterated milk, see Report on Fresh and Condensed Milk in the Fourth Annual Report (1853-4) of the New York State Board of Health. I n conclusion : The lactometer is an accurate instrument for taking the specific gravity of milk. The specific gravity of the entire quantity of milk given by a healthy cow a t her regular time of milking is rarely, if ever, below 1.049. The specific gravity of pure milk increases with the quality, that is, with the dccreased percentage of water ; while it decreases in proportion to the water added itnd increases with the cream removed, either or both adnlterations being apparent to the senses of an expert. If the test is performed by an expert, it is impossible to tamper with a sample of milk, to the extent of commercial adulteration, without being detected by the specific gravity taken in connection with evidence of the senses.
