Theory of Oentrifugal Separation. 109 
outlet. In this way the milk as it enters is divided 
into two portions: one, the larger, drawn from the 
extreme 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 matters with some fat globules 
adhering, and any particles 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  separa- 
tion.—The completeness of the separation is depend- 
ent upon the centrifugal force generated, the rate 
of inflow, the temperature of the milk, and the 
physical condition of the milk. : 
The amount of centrifugal force generated depends 
upon the diameter of the bowl and the velocity of 
rotation. 
Roughly speaking, the centrifugal force increases 
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