326 



THE MONTHLY BULLETIN. 



ounces of water are used, while for sodium cj^anide one and a half liquid 

 ounces of sulphuric acid and two liquid ounces of water are used. As 

 this is a fixed ratio in each case, graduates have been made to measure 

 out the exact amount of the liquid required in the terms of the number of 

 ounces of cyanide ; for instance if it required twelve ounces of sodium 

 cyanide for a dose the acid graduate is so scaled that it would be filled 

 to the twelve ounce line, which would mean eighteen liquid ounces and 

 the water graduate to the twelve-ounce line, which would be twenty- 

 four liquid ounces. Such a scheme makes it -unnecessary to make men- 

 tal calculations and thus avoids mistakes. .... 



ACID GENERATORS. 



Acid generators are earthenware pots usually made in gallon, two- 

 gallon and three-gallon sizes and with or without lids (Fig. 314). The 

 lid has long been recognized as a valuable adjunct to a generator by 

 throwing the gas outward, thus preventing burnings directly above the 

 generator. It also prevents the sputtering over of the acid due to the 

 violent chemical reaction vv'hen the cyanide is added. So far there ap- 



FiG. 313. — A specially constructed chemical wagon. (Photo by. Fawcett. ) 



pears to be no lid manufactured which is entirely satisfactory, though 

 nearly all fumigators prefer those on the market to the open generator. 

 A suitable lid should be light and hinged so as to admit of easy 

 emptying. 



The two-gallon generator is more generally used because it more 

 nearly meets the requirements of large and small doses. Care should 

 be exercised not to fill a single pot more than one third full of acid and 

 water before the cyanide is added as the contents may boil over and nuich 



