CHAPTER II 

 HOW THE GAS IS MADE 



T|HK chemicals used for generating hydrocyanic 

 acid gas are ( i ) fused cyanide of potassium 

 (KCN), (2) sulphuric acid (H 2 SO 4 ), and 

 (3) water (H 2 O). The cyanide should be 

 guaranteed 98-99 per cent. , which is practically chem- 

 ically pure. There is upon the market in some places 

 an old brand of cyanide of about 5860 per cent, 

 purity. This should be avoided. 



The best grade of commercial sulphuric acid, with 

 a specific gravity of at least 1.83, should be used. A 

 grade known as chamber acid used ordinarily in the 

 manufacture of fertilizers will not do, and under no 

 circumstances should it be employed. Water from any 

 source will sufiice, the only requisite being that it 

 should be clean. 



In combining the chemicals (i), measure the acid in 

 the glass beaker marked ounces on the side, and pour 

 it in an earthenware crock, wooden bucket, tub, or 

 pickle jar; (2), measure the water in the same beaker 

 and pour it on the acid; (3), drop in the cyanide, bag 

 and all, if wrapped in paper, close the door or drop the 

 tent quickly, and leave desired length of time. 



Action of the chemicals. When the water is poured 

 into the jar upon the acid, a slight evolution of steam 

 arises, which is not dangerous. As soon as the cyanide 

 is dropped in the acid and water there is a bubbling 



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