102 The Phosphates of America. 



If the entire product from the chambers were put through 

 the Glover tower, the gravity could be run up to 60 or even 62 

 B. and the concentrated liquid could be easily reduced to any 

 required strength by the addition of water, as shown by a table 

 in a subsequent chapter. 



The composition of pure H 2 SO 4 is made up of 81.63 parts of 

 sulphuric anhydride and 18.37 parts of water. 



For every 100 pounds by weight it contains: 



Hydrogen 2.041 pounds 



Sulphur 32.653 " 



Oxygen 66.306 " 



Total 100 



Hence the quantity of acid produced by 100 pounds of sulphur 

 should be: 



Sulphur 100. 00 pounds 



Hydrogen 6.20 " 



Oxygen 199.80 " 



Total H 2 SO 4 equals 306 



In other words, one pound of sulphur, when properly burned, 

 theoretically yields 3.06 pounds of the monohydrate, with a 

 specific gravity of 1.842 at 15 C. and 66 according to 

 Beaume's hydrometer. In practice, a regular average yield of 

 about 2.95 pounds of 66 Beaume, or even 4.50 pounds of 52 

 Beaume, is considered an excellent result, and while the state- 

 ments of manufacturers who claim to do better than this must 

 be received with caution, it may nevertheless be laid down as an 

 axiom that from every pound of sulphur really burned, whether 

 it be in the form of brimstone or of pyrites, the same amount of 

 sulphurous-acid gas, and consequently of sulphuric acid, will, 

 under all equal conditions, be produced. 



A reference to the annexed analytical table will show the pro- 

 portion of sulphur contained in the pyrites now mined and used in 

 this country. 



