Milk. 
319 
broken, according to the degree of agitation to which the milk 
was exposed, in consequence of which the cream in the different 
samples had a variable composition. 
On comparing the milk of the 25th of March with that of the 
4th of March, it will be seen that the latter, notwithstanding its 
containing more pure fatty matter, threw up a little less cream in 
bulk than the former. 
The subjoined table gives the specific gravity of the different 
samples of milk of the 25th of March, before and after skimming. 
All determinations were made at 62^ Fahr. : — 
Specific Gravity at 62° F. 
before skimming. 
Specific Gravity 
at 62° F. 
after skimming. 
By Hydrometer. 
By Direct 
Weigtiing. 
By Direct 
Weighing. 
„ + 10 per cent of water .. 
.. + 20 „ 
,. +30 „ 
+ 40 „ 
+ 50 
1 • 0320 
1-0285 
1-0250 
1-0235 
1-0200 
1-0170 
' 1 '03141 
1 -0295 
1-0257 
1-0233 
1-0190 
1-0163 
1-0337 
1-0308 
1-0265 
1-0248 
1-0208 
1-0175 
This second series of experiments was made with great care, 
and the numbers obtained are probably more reliable than those 
of the first series. 
It will be seen that the hydrometer indications agree very 
nearly with the specific gravity determinations by direct weigh- 
ings. It follows, further, from the preceding experiments : — 
1. That good new milk has a specific gravity of about 1-030. 
2. That skim-milk is a little more dense than new milk, its 
specific gravity being about 1034. 
3. That milk which has a specific gravity of 1-025, or less, is 
either mixed with water, or naturally very poor. 
4. That when milk is deprived of about 10 per cent, of cream 
by bulk, and the original volume is made up by 10 per cent, of 
water, the specific gravity of such skimmed and watered milk is 
about the same as that of good new milk. 
5. That when unskimmed milk is mixed with only 20 per cent, 
of water, the admixture of water is indicated at once by the hydro- 
meter, which gives for such milk a specific gravity of about 
1-025. 
6. That for these reasons the hydrometer, or " lactometer," 
which gives the specific gravity of milk, is well adapted for de- 
tecting the admixture of water in milk, or to show an unusually 
poor condition of undiluted milk. 
In conclusion, it may be stated that the facts mentioned under 
VOL. XXIV. Y 
