INJURIOUS INSECTS OF 1903. HI 



enclosed. To determine the exact amount of cyanide 

 necessary to fumigate a room, car, ship or building of any 

 kind, the cubic contents must be accurately computed. 

 As an example, a room 20x30x10 feet contains 6,000 cubic 

 feet of air space. To estimate the amount of cyanide re- 

 quired for this enclosure, multiply 6,000 by 0.25; thus: 

 6,000x0.25=1,500 grammes. To reduce this to ounces, 

 divide by 28.35, ^s there are 28.35 grammes in an ounce ; 

 thus: 1,500-^28.35=53 ounces, the exact amount of cy- 

 anide needed for the enclosure. It is now easy to deter- 

 mine the amount of acid and water, as a half more acid, 

 liquid measure, than cyanide, and a half more water than 

 acid are used; thus: 53-^2:=26.5, which, added to 53, 

 equals 79.5 ounces of acid, or practically 5 pounds, liquid 

 measure. Again, 79.5, or practically 80, as we usually 

 discard fractions, divided by 2 equals 40, which, added to 

 80, makes 120 ounces of water." — Fumigation Methods, 

 Johnson. 



In combining the chemicals, measure the acid and pour 

 it into an earthenware dish, wooden bucket, tub, etc. ; 

 measure the water and pour it in with the acid ; if a room 

 is to be fumigated have the bag containing the potassium 

 cyanide suspended from a pulley directly above the jar of 

 acid, and from a distance drop in the cyanide, bag and 

 all ; if the space is under a tent, the cyanide can be 

 dropped in directly from the hand; close the door tightly 

 or drop the tent quickly, and leave for the desired length 

 of time. 



For nursery stock an air-tight building, made by 

 double boarding and padding with felt, etc., is employed, 

 into which the nursery stock is taken and there fumigated. 

 Exposure, 30 to 40 minutes. 



For dormant trees a canvas tent is used to enclose the 

 entire tree, or if the tree is small enough a fumigator, a 

 box frame covered with canvas, is placed over the tree, 

 and the gas generated in the enclosed space. An expos- 

 ure of 30 minutes is usually sufficient. 



For greenhouse pests, although the treatment is yet in 

 the experimental stage, some horticulturists fumigate 



