318 
Milk. 
GraTity. ^^^^ 
Pure milk at 62= Fahr r0320 .. llj 
and 10 per cent, of water at 02° Fahr. .. 1-0315 . . 10 
20 „ „ 1-0305 .. 9 
30 „ „ 1-0290 .. 8 
40 „ „ 1-0190 .. 6 
50 „ „ 1-OlCO .. 5 
After removal of the cream from each sample, the specific 
gravity of the skim-milk at 62° Fahr. was determined, and found 
as follows : — 
Pure skim milk 1-0350 
„ and 10 per cent of water 1-0320 
„ 20 and 30 per cent, of water (spoiled by accident). 
„ 40 per cent, of water 1-0210 
50 „ I-OISO 
In the preceding Experiments the specific gravity of the milk 
was determined by means of an hydrometer. But as results 
obtained in this way are not considered so accurate as determi- 
nations made by direct weighings on a delicate balance ; and, 
moreover, as the second of the series accidentally failed, I made 
a new set of experiments on the 25th of March last. 
The milk was analysed, and had the following composition : — 
Water 88-10 
Pure fatty matters (butter) 2-61 
*Casein and albumen 3-12 
Milk- sugar 5-46 
Mineral matters (asb) "71 
100-00 
*Containing nitrogen '.50 
Percentage of solid matter 11*90 
Its specific gravity at 62', ascertained by hydrometer, was 
1-0320; and by direct weighing 1-03141. After standing 24 
hours it gave 12 per cent, of cream by volume ; having Jjeen 
shaken, and then left to stand for 24 hours, it gave 8 per cent, 
of cream by volume. 
Percentage- 
of Cream 
by bulk. 
Tbis milk and 10 per cent, of water, after 24 bours' standing at G2=, gave 10.^ 
„ 20 „ „ „ 10 
„ 30 „ „ „ G 
40 5 
»> 50 „ „ 4j . 
The relative proportions of cream in these samples do not agree 
with the amount of water that has been purposely added to each. 
I account for these variations by the fact that in mixing the milk 
and water together, the cream globules have been more or less 
