68 



TIfE BOOK OF BUTTER 



speeil. It is rcixn'ted that at one time early in the his- 

 tory t)f centrifugal separators, before the machines were 

 perfected, a separator howl burst at Hazelton, Kansas, 

 and killed se\'en ])ersons. A few similar accidents have 

 happened before and since because machines are often 

 overspeeded. This means that an operator should be well 



acquainted with the machine 

 itself and with the important 

 considerations affecting the sep- 

 aration of milk. In the follow- 

 ing paragraphs are some of these 

 important factors. 



47. Regulation of the fat in 

 the cream. — The richness, or 

 the percentage of fat, in cream 

 derived from whole milk by the 

 use of a centrifugal separator is 

 regidated !)>• either a cream 

 screw or a skimmed-milk screw. 

 Two main facts should be re- 

 membered when one sets either 

 of these screws. The first is 

 that the richness of the cream 

 depends on the point in the 

 bowl from which it is drawn. 

 The richest cream is drawn 

 from the center of the bowl, 

 and the richness decreases as the distance from the 

 center incrciiscs. The other fact is that the smaller the 

 proportion of crcatn to skimmed-milk, tlie richer is the 

 cream in f:it. The percentage of fat in cream should 

 be rcgulatcci :icc(irding to the use that is to be made 

 of the cre:iin. Ordinarily for churning purposes, the 



3 U'ri hiiih. TIlc Ix.wl way 

 11. i iiii'hea in iliamutur. 



