( IGO ) 
IX. — Oil the Composition of Cream antl Skim-milk obtained hy 
De LavaVs Ccntrifiujal Cream-scparntor. By Dr. AUGUSTUS 
VOELCKER, F.R.S. 
DuiUXG the Exhibition at Kilburn I had an opportunity of 
ascertaining the composition of the cream and skim-milk which 
were obtained in the Kilburn trials with De Laval's centrifugal 
cream-separator, and as the results of my analyses are of some 
interest to dairymen, they may be briefly recorded in the 
' Journal of the Royal Agricultural Society.' 
The following is the composition of the milk used in the 
Kilburn trials on the 4tli of July, 1879, and of a sample of the 
skim-milk produced by Laval's cream-separator. 
.New JlilU. 
Skiiii-iiiilk 
Iroui 
Laval's 
Creani- 
Separatur. 
Water 
ST- 72 
90-71 
3-4.5 
-22 
Milk-sui;av 
5-11 
5-12 
•60 
•64 
100-00 
100-00 
.. . , 1 
•50 
•53 
1 
Milk well skimmed in the ordinary manner contains on 
an average about J per cent, of butter-fat, whereas the skim- 
milk obtained in Laval's cream-separator did not retain quite 
J per cent. 
Thus of the 'oi per cent, of butter-fat (in round numbers) 
3:^ per cent, were obtained in the cream, and onlv j per cent, 
of fat passed into the skim-milk, affording a striking proof of 
the perfect manner in which the butter- forming constituents 
are separated from milk in passing through Laval's rotatory 
machine. 
Had the milk been set in pans and skimmed thoroughly in 
the usual manner, instead of per cent, of pure butter-fat only 
2J per cent, would have been obtained from the new milk ; or, 
in other words, by Laval's separator IK) per cent, of the butter- 
fat were obtained in the cream and 7 per cent, only left in the 
skim-milk ; whilst by the usual plan of skimming only 78^ per 
