SEPARATION OF CREAM. 139 



of the skim-niilk outlet, due to a more rapid discharge 

 through the skim-milk outlet. The slower the bowl re- 

 volves the less skimmed milk will be discharged, and conse- 

 quently, if the inlet is constant, more and thinner cream will 

 be the result. It should be stated in connection with this 

 that the efficiency of skimming depends to a large extent 

 upon the speed, and if attempts are made to increase the amount 

 of cream and decrease the percentage of fat in it, by lowering 

 the speed, an abnormal amount of fat will be left in the skimmed 

 milk. 



4. Temperature. — The temperature of milk usually does not 

 influence the relative amount of milk and cream very much. 

 The higher the temperature the more fluid the milk becomes, 

 and consequently, all other conditions being the same, shghtly 

 more milk will run through at a high temperature than is the 

 case with a lower temperature. This increase will show itself 

 chiefly in the amount of cream, as the higher temperature 

 has a greater relative effect upon the cream than it has upon 

 the milk. By increasing the temperature of the milk, shghtly 

 more and thinner cream is obtained. 



Conditions Affecting Efficiency of Separators. 



I. Manner of Heating Milk. — Owing to the fact that fat- 

 globules rapidly change their shape and property by exposing 

 them to heat and excessive agitation, it is essential that care 

 should be taken in heating milk previous to skimming. When 

 fat-globules are heated they become more liquid, and if stirred 

 very much the clusters of fat-globules break up more rapidly. 

 The individual globules, if stirred violently, will break or sub- 

 divide into several small ones. The higher the temperature 

 of the milk, the more fluid the milk becomes, and the easier 

 the separation. If milk is stirred violently, the individual fat- 

 globules break up into smaller ones, which are separated from 

 milk with difficulty. The following table * illustrates what 



* Hoard's Dairyman, Fort Atkinson, Wis. 



