76 



THE BOOK OF BUTTER 



the manufacturer is careful not to state a rate of speed 

 that will give results just above the border line of poor 

 separation. If these instructions of the manufacturers 



are followed carefully, the 

 45- separation of milk will be 



found to be thorough. The 

 fact remains, however, that 

 the rate of speed may drop 

 several hundred revolu- 

 tions of the bowl below the 

 number designated, and 

 still the skimmed-milk will 

 contain approximately the 

 same percentage of milk-fat 

 as when the bowl is re- 

 volving at the so-called 

 normal speed. In the case 

 of the hand separators, 

 this amounts to five or ten 

 revolutions of the crank 

 less than the number given 

 for normal speed. 



50. Percentage of fat in 

 whole milk. — The percent- 

 age of fat in whole milk is 

 variable. In this respect, 

 the milk from individual 

 cows may vary as much as 

 two or three per cent from 

 one milking to another, and yet the cow may appear 

 to be in a normal condition. The fat-content of the 

 milk of a herd is not so variable as that from a single 

 cow. Other things being equal, the larger the herd, the 



Percentage 3 4 6 3 4 5 



Separator 1 Separator 2 



Fig. 38. — A diagram representing 

 the percentage of tat in cream aa 

 influenced by tlie percentage of fat 

 in whole milk. The figm-es on the 

 left of the diagram represent per- 

 centage of fat in cream, and those 

 underneath represent percentage of 

 fat in whole milk. 



