TESTING DAIRY PRODUCTS BY THE BABCOCK TEST. 



71 



\ 



7 



the rate of 1,000 to 1,200 revolutions per minute. A steam 

 turbine machine is best for this purpose, but a hand or belt power 

 machine can be used, if hot water is put in the pan to keep the 

 fat melted. After the whirling is completed, the percentage of 

 fat can be read in the usual manner. 



For the modified test no change of 

 apparatus need be made; the writer, 

 however, prefers to have the base 

 portion of the bottle graduated, so 

 no' acid measure is required and only 

 one pouring of the acid is necessary. 

 By having the bottle marked at the 

 point A (fig. 6), at which mark it 

 holds 37.5 cubic centimeters, one can, 

 after the milk is measured in with the 

 pipette, run the acid in until it is filled 

 to this point. It was found imprac- 

 ticable to use a bottle like the one for 

 cream described farther on, because of 

 the larger amount of curd in milk than 

 in cream and the small size of the neck 

 of the milk bottle, necessitating more 

 space for shaking, breaking up the 

 curd and dissolving it in the acid. 



It would appear that the time re- 

 quired for the bottles to stand after 

 the acid is mixed with the milk, would * 

 offset that gained by omitting the 

 second whirling, which is made in the 

 old method; but the writer has often 

 found it necessary with many kinds of 

 milk, especially with that from cows 

 much advanced in the period of lacta- 

 tion, to allow the bottles to stand 

 awhile, even when working the two 

 whirling method, in order to get a clear separation of fat. How- 

 ever, every one who does much testing should have at least two 

 sets of bottles, so there would be no loss of time by this process. 

 When two sets of bottles are at hand, one set, charged with 

 the milk and acid, can stand while the second set is being filled, 



