332 MILK AND MILK PRODUCTS. XIV. 



40% ; whilst with the separator, by adjusting the rate at which 

 the milk passes away, almost any richness of cream may be 

 obtained. 



The aqueous portion of cream contains the usual solids of 

 milk almost in the same proportion as in milk itself. The 

 amount of solids not fat is usually slightly higher than in milk, 

 due probably to evaporation of water during the setting. This 

 is especially the case with " clotted cream," prepared by the 

 Devonshire method, and whose composition is more uniform 

 than that of ordinary cream. According to Richmond the 

 average composition of this substance is water 34-26%, fat 

 58-16, ash 0-60, solids not fat 7'52. 



The specific gravity of cream can only conveniently be deter- 

 mined directly if its fat is below 30%. If stiffer than this it 

 must be diluted with an equal volume of separated milk and 

 the specific gravity of the mixture taken. Richmond gives the 

 following numbers : 



Specific gravity. % fat. Specific gravity. % fat. 



1-0035 29-0 1-0125 21-3 



1-0070 26-0 1-0130 20-8 



1-0090 24-0 1-0210 13-5 



arid he gives as a formula connecting the specific gravity 

 and percentage of fat in cream the following : 



f* 

 F 32-0-0-892 jy 



where F = per cent, of fat, G = lactometer reading (i.e., specific 

 gravity x 1000 1000) and D = true specific gravity. 



This formula does not apply to clotted cream. 



Skimmed Milk is of course similar in composition to ordi- 

 nary milk, with the exception of containing little or no fat. 

 The other constituents water, sugar, casein, &c. though 

 preserving the same ratio to each other, are slightly raised in 

 percentages. Skimmed milk from shallow setting usually con- 

 tains anything between 0-4 and 2% of fat, while with a good 

 separator the amount is usually from 0*05 to 0'3 %. Its specific 



