64 Testing Milk and Its Products. 



per is soon dissolved by the acid and rendered useless. 

 If the bottle is left uncorked, the acid will absorb 

 moisture from the air and after a time will 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 cov- 

 ered 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 

 should 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; the ammonia must, however, be 

 applied while the stain is fresh, and is in its turn 

 washed off with water. 



73. Testing the strength of acid. The strength of 

 the acid can be easily tested by the use of a balance like 

 that shown in fig. 34 (91). A dry test bottle is weighed, 

 and then filled with acid exactly to the zero mark, or 

 to any other particular line of the scale. It is then 

 again weighed accurately; the difference between the 

 two weights will give the weight of the acid in the bot- 

 tle. The bottle is then emptied and thoroughly rinsed 

 with water (until the water has no longer an acid 

 taste) ; it is then filled with water to the same line as 

 before and weighed; the difference between this weight 

 and that of the empty bottle gives the weight of the 



