Calculation of Butter- and Cheese Yield. 191 



salt, etc., in the manufacture of butter. Considering 

 first the losses of fat in skim milk and butter milk, the 

 separator will usually, when run at normal speed and 

 capacity, leave the same per cent, of fat in skim milk, 

 whether rich or poor milk is skimmed. An exception 

 to this may be found in separating rich milk having 

 large fat globules, or milk from fresh milkers, in either 

 of which cases the large size of the fat globules occa- 

 sions a more complete separation of fat by the centri- 

 fugal force. But generally speaking, the statement 

 holds good that the total loss of fat in separator skim 

 milk is a factor of the quantity of milk run through the 

 separator, rather than of its quality. 



216. The losses from poor, rich and average milk, as 

 received at creameries and cheese factories, can be traced 

 from the following statement; this gives the quantities 

 of fat lost in handling milk of four grades, viz.: 2.5, 

 3.5, 4.0 and 6.0 per cent., in case of each grade calcu- 

 lated to a standard of 100 Ibs. of fat in the milk. 



To supply 100 Ibs. of fat would require the following 

 amounts of the different grades of milk: 



4000 Ibs. of milk testing 2.5 per cent will contain 100 Ibs. of fat. 

 2857 " " " 35 " " " 100 " " " 



2500 (( tt 40 ( ( (i ( ( -J^QQ (i ( ( tt 



1666 ":."" " 6.0 " " " 100 " (< " 



Assuming that the skim milk contains .1 per cent, of 

 fat and makes up 85 per cent, of the whole milk, and 

 that the butter milk tests .3 per cent., and forms 10 

 per cent, of the whole milk, the butter-fat record of 

 the quantities of different grades of milk containing 100 

 Ibs. of fat will be as given in the following table. Cer- 



