Theory of Centrifugal Separation 181 



nearest the outside of the bowl. These outlets are made 

 of such size in comparison with the size of the bowl, 

 the speed of the machine, and the size of the inflow 

 tube, that they have a capacity of discharging the 

 milk from .4 to .9 as fast as it runs in; the remain- 

 ing contents of the bowl are then forced toward the 

 center, and find an exit through the cream outlet. 

 In this way the milk as it enters is divided into 

 two portions: one, the larger, drawn from the ex- 

 treme outer portion of the bowl, consisting of 

 skimmed milk, and the other, the smaller, escaping 

 from the center of the bowl, the cream. A third 

 portion also usually accompanies centrifugal sepa- 

 ration. A part of the semi-solid constituents of 

 the milk, being heavier than the milk serum, are 

 thrown to the outside of the bowl, and adhere to 

 the walls in the form of a creamy or gelatinous mass 

 which is ordinarily called separator slime. It consists 

 mainly of albuminous matter with some fat globules 

 adhering, and any p'articles of dirt or foreign mat- 

 ter that may be mechanically mixed with the milk. 

 It varies greatly at different times and seasons. 

 Usually the amount is not large, but not infrequently 

 it is sufficient to clog the outlets of the separator 

 after a run of an hour or two. The separator slime is 

 largely composed of matter deleterious to the qual- 

 ity of cream and butter, and its removal is to a 

 great extent a purification of the cream. The various 

 conditions affecting this operation are as follows: 



Conditions affecting the completeness of separation. 

 The completeness of the separation is dependent upon 



