86 



MODERN METHODS OF TESTING MILK 



parts of the sample of buUer, prepared as above de- 

 scribed, small pieces of butter and places them in the 

 funnel-shaped tube of the bottle until the sample weighs 

 9 grams. The bottle is then placed in hot 

 water until the butter melts and runs into 

 the test-bottle. The fat adhering to the 

 inside wall of the funnel is washed down 

 into the bottle with 8.8 cc. of hot water 

 and the same amount of sulphuric acid 

 (8.8 cc.) is added. After the contents 

 are thoroughly mixed, the bottle is placed 

 in a tester and whirled for about 5 min- 

 utes. To read the result, fill the funnel- 

 shaped tube with hot water, which raises 

 the fat-column in the graduated neck. 

 By gently pressing down or gently draw- 

 ing up the rubber cork at the top of the 

 graduated neck, the fat-column may be 

 moved in the graduated neck so as to 

 bring the lower end of the fat-column 

 level with zero mark, which is indicated 

 by a ring below the bulb. The percent- 

 age of fat is read directly. Before read- 

 ing the test, let the bottle stand for ten 

 minutes in water at 120 I3OF. 



FIG. 30 



BOTTLE FOR USE 



IN TESTING 



BUTTER 



GRAY'S RAPID TEST FOR WATER IN BUTTER 



The method described below for the determination 

 of water in butter has been recently devised by Mr. 

 C. E. Gray, Assistant Dairyman in the Dairy Division, 

 Bureau of Animal Industry, U. S. Department of Ag- 

 riculture. (Circular No. 100, Dec. 31, 1906.) The 



