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THE ESSENTIALS OF AGRICULTURE 



system and gave an im- 

 perfect separation, leaving 

 from one fifth to over one 

 third of the fat in the skim 

 milk. Later it was discov- 

 ered that a more complete 

 separation could be insured 

 in less time by setting the 

 milk in deep, narrow cans. 

 This was known as the 

 deep-setting system. Under 

 this system only about one 

 fifteenth of the butter fat 

 was lost, because the milk 

 cools more quickly in the 

 deep cans 



FIG. 189. The barrel churn 



and the 

 quicker it 



cools, the more complete is the separation. 

 491. The Centrifugal System. By this 

 system less than a hundredth of the fat is 

 left in the skim milk. The milk is poured 

 through a bowl that is revolved at a high 

 speed. The heavier particles of the milk are 

 thrown to the outside of the bowl, while the 

 lighter particles, the fat globules, are crowded 

 toward the center. Near the outside of the 

 bowl is an outlet for the removal of the skim 

 milk, and near the center is a cream tube 

 through which the fat globules, with more or 

 less milk, are removed. Centrifugal sepa- 

 rators differ in construction, but each kind 

 has its advantages and each will do good 

 work under proper conditions. Advantages 

 of the centrifugal separator (Fig. 188) are: 

 the cream can be separated immediately and 



The old- 

 fashioned dash 

 churn 



