448 



HOUSEHOLD INSECTS 



into the jars placed in each room with the cyanide in bags 

 beside them. When all is ready, the operator should go 

 to the top floor and work downward, because the gas is 

 lighter than air, and tends to rise. 



The following account of the manner in which the 

 author has fumigated a large dormitory for several suc- 

 cessive years will give the method of procedure in working 

 with an entire building of large size : — 



The dormitory building in which the work has been 

 done is a large four-story structure in the form of an E, and 

 contains, all told, 253 rooms of different sizes on the differ- 

 ent floors. It takes about 340 pounds of cyanide (98 per 

 cent pure) and the same quantity of sulfuric acid to 

 give the building a single treatment, not including the 

 halls, which are thoroughly scrubbed with lye and water. 



Our first work was to measure the rooms and compute 

 the cubic contents of each. With the exception of a few 

 corner rooms, they are as follows : 



In computing the amounts of cyanide, water, and acid 

 to be used, we always raise the cubic feet in any given 

 room to the next even hundred. For example, the capac- 

 ity of each room on the fourth floor, which is I960 cubic 

 feet, was considered to be 2000 cubic feet. 



1 At this time we used 2 ounces of water to one ounce of acid and 

 considered 30 cubic centimeters as the equivalent of 1 ounce. 



