336. 



STATE BOARD OF AGRICULTURE. 



An even number of bottles should always be whirled at the same time 

 and they should be placed about the disc in opposite positions if the 

 machine is not filled so that the equilibrium of the tester will not be 

 disturbed. 



In the case of hand testers, it is sometimes beneficial to put hot water 

 in the jacket during cold weather to keep the bottles warm enough; 

 the water should not rise quite to the level of the bottoms of the test 

 bottles when the machine is at rest. 



Adding Hot Water. — 



Water used during the test should be at a temperature of about 130° F. 

 The best water to use is that free from minerals, hence rain water or 

 pure distilled water is good. 



The object in washing the fat with water twice is to free it from all 

 adhering impurities. 



Reading the Percentage of Fat. — 



The line of division between the fat column and the liquid beneath is 

 nearly straight, making it easy to read. But the upper surface of the fat 

 column is markedly concave, making it somewhat difficult to determine 

 the proper point at which to take the reading. The correct reading is 

 taken at the line where the extreme upper limit of the fat column touches 

 the side of the neck. See ill. 5. 



Illustration 5. 



Chemists have found that enough fat is left in the bowl of the bottle 

 to make up for the concavity in the upper surface of the fat column. 

 The length of the fat column is first determined b*y means of the 



