The Babcock Test. 63 



cent. fat. Some of the most recent makes of turbine test- 

 ers are provided with holes in the cover and dampers. 

 A thermometer is also placed in the cover. 



3 SULPHURIC ACID. 



72. The sulfuric acid to be used in the Babcock test 

 should have a specific gravity of 1.82 -1.83. 1 The com- 

 mercial oil of vitriol which can be bought for about 

 2 cents a pound in carboy lots, is commonly used. One 

 pound of acid is sufficient for fifteen tests. The acid 

 should be kept in stoppered glass bottles, preferably 

 glass or rubber stoppered ones, since a cork stopper is 

 soon dissolved by the acid and rendered useless. If the 

 bottle is left uncorked the acid will absorb moisture from 

 the air and will after a time become too weak for use in 

 this test. Lead is the only common metal which is not 

 dissolved by strong sulfuric acid; where considerable 

 milk testing is done, it is therefore desirable to provide 

 a table covered with sheet lead on which the acid may 

 be handled. 



The acid dissolves iron, tin, wood and cloth, and burns 

 the skin. If acid is accidently spilled, plenty of water 

 should be used at once to wash it off. Ashes, potash, 

 soda, and ammonia neutralize the action of the acid, and 

 a weak solution of any one of these alkalies can be used 

 after the acid has been washed off with water. The red 

 color caused by the action of the acid on clothing can be 

 removed by wetting the spot with weak ammonia water; 



i A specific gravity of 1.82 means that a given volume of the acid weighs 

 1.82 times as much as the same volume of water at the same temperature 

 (see also under Lactometer, 106). 



