SEPARATION OF CREAM. 135 
it immediately begins to separate into three distinct layers. 
The centrifugal force acting in a horizontal direction forces 
the heaviest portions of the milk and the precipitated albu- 
minoids, ash, filth, and a multitude of germs over next to 
Fig. 73.—The Reid separator. Fic. 74.—The Sharples separator. 
the wall of the separator bowl, and into a solid and more or 
less gelatinous layer, which is known as the “ separator slime.” 
In very impure milk this substance is so plentiful that it is 
likely to clog the separator in a very short time, and before 
much separation is accomplished it is necessary to clean out 
the bowl. The second layer is the skim-milk, while the cream, 
being the lightest, is forced to the center of the bow] and forms 
the third portion mentioned. There is no distinct line of 
demarcation between the layers of skimmed milk and cream. 
They overlap each other and form a sort of zone, rather than 
a sharp separation. The richest cream is nearest the center 
of the bowl, and gets thinner toward the outer portion of the 
bowl; consequently, by turning the outlet for the cream, or 
cream-screw, nearer the center of the bowl, the cream is increased 
