THE METHOD BRIEFLY DESCRIBED 355 



of cyanide required having been determined, order it from a 

 reliable dealer, insisting upon 98 or 99 per cent grade of fused 

 cyanide of potash. Avoid the use of a low grade. 



A half more sulfuric acid than cyanide will be needed. For 

 instance, if a building required 500 pounds of cyanide, 750 pounds 

 avoirdupois of sulfuric acid are needed. This acid must be the 

 best grade of commercial add with a specific gravity of 1.83 or 

 over. Anything below that should be rejected. 



The water should always be placed in the jar first (see page 

 62 for specific directions) and the acid added. Each jar will 

 contain six and three-quarter pounds of water (about three and 

 one-half quarts) and four and one-half pounds avoirdupois of acid. 

 If it is impossible to secure cyanide of potash, cyanide of sodium 

 may be employed, using one-half more acid; for example, three 

 pounds of cyanide of potash call for four and one-half pounds of 

 acid, while three pounds of cyanide of soda would require six and 

 three-fourths pounds of acid. Further, three pounds of cyanide 

 of soda will give off more gas than an equal amount of cyanide of 

 potash. Or, in order to give economy of material due considera- 

 tion, only four-fifths as much cyanide of sodium is necessary as 

 cyanide of potash. When three pounds of cyanide of potash are 

 called for, one may employ two and one-half pounds of cyanide 

 of sodium. The same quantity of acid and water as directed for 

 use with the potash compound will give best results. 



Get from a grocer a hundred or more manila sacks, No. 8, 

 10, or 12. One will need two sacks for every three pounds of 

 cyanide. Do not use the heavy paper sacks, so-called "sugar 

 sacks." Cloth sacks must never be employed. These paper bags 

 are to be doubled, one being carefully placed inside another. The 

 cyanide, after being broken up, is placed in these sacks within an 

 hour or two of the time when it is to be used, but must not be 

 left in the sacks for any length of time four hours or over night, 

 for example. Torn sacks must be rejected. 



When ready to fumigate, but not before, this cyanide should 

 be done up in three-pound packages, use double manila bags 

 that is, one inside another of such size as to permit the paper 

 to be brought together and securely tied above the cyanide, 

 without tearing. As many four-gallon crocks should be rented or 

 purchased as there are packages of cyanide. If, however, the 

 entire plant is not to be treated at one time, only sufficient jars 

 are needed for the portion to be treated, since the same crocks 



