MILK AND ITS CARE. 181 



to place the bottle in hot water between whirl- 

 ings before making the reading. The reading 

 of the fat column is taken from the extreme top 

 to the extreme bottom. 



(8) TESTING SKIM-MILK AND BUTTERMILK. 

 -The operator of a butter or cheese factory 



should keep close watch on the losses of butter 

 fat in the skim-milk and buttermilk by making 

 frequent tests. For testing these products 

 exactly the same method is used as described 

 for testing milk, except a special kind of bottle, 

 having two necks, is used, which allows finer 

 readings to be made. Each small division on 

 these bottles reads .05 of i per cent., and by 

 estimating readings can be made to .01 of i per 

 cent. 



(9) TESTING CREAM. It is far more difficult 

 to make an accurate test of butter fat in cream 

 than in milk. Cream varies greatly in amount 

 of butter fat present, ranging from 12 or 15 per 

 cent, to 60 per cent, of butter fat. As the milk 

 test-bottle only reads to 10 per cent., it is neces- 

 sary to have a special testing-bottle for cream 

 where much testing is to be done. 



Cream can be tested in ordinary milk test' 

 bottles by adding two measures of water to one 

 of cream, then testing the mixture in the same 

 manner as for milk, multiplying the reading by 

 three. When the common cream test-bottles 

 are at hand which read to 30 per cent., the 17.6 



