April, ’24] 
SASSCER & WEIGEL: GREENHOUSE FUMIGATION 
215 
poisonous gas. To avoid this risk the following equipment was de¬ 
vised. 
Small bottles were spaced equidistant from each other and fastened by 
means of a small wooden plate to a revolving shaft made of one-half inch 
gas piping. Pipe extensions of a “T” at one end of the shaft served as a 
handle for turning over all the bottles at one time. The total amount of 
liquid hydrocyanic acid required for a given charge was divided among a 
definite number of bottles which were kept corked. When the gas was 
to be released the stoppers were removed in succession beginning at the 
far end and moving toward the door. The bottles were then upset simul¬ 
taneously by giving the shaft a half turn. The evaporation surface 
under each bottle was greatly increased by spreading newspapers in a 
cone-shaped manner over an inverted 10 inch flower pot. 
In utilizing the pot method of generating the gas the bottles were 
omitted, and in lieu of these, cups 3 inches high made of Ordinary metal 
spouting were attached to the wooden blocks on the shaft (Fig. 4). 
After pouring the water and acid into the generators, one of which is 
placed below each cup, the fumigator distributes the packages of sodium 
cyanide in the cups and by a turn of the handle the chemical is dumped 
simultaneously into each generator. In this manner he is not exposed 
to the gas as may sometimes be the case when the packages are dropped 
individually into the water and acid. 
After trying out this method several times successfully in a small 
greenhouse the device was installed in a long, single range type approxi¬ 
mately 225 feet in length. This improvement worked so satisfactorily 
that it was deemed desirable to bring it to the attention of entomologists 
since it overcomes the necessity of being in the house as the chemicals are 
mixed. Moreover, this feature will undoubtedly stimulate more interest 
among florists when they become familiar with it in the use of this gas. 
The fact that one man can safely fumigate a house or possibly a series 
of open range houses by this method should influence its adoption. 
In this connection it seems desirable to refer to Figures 5 and 6 
which illustrate a convenient arrangement which recently has been 
devised for opening the ventilators from the outside of the greenhouse. 
Experiments With Liquid Hydrocyanic Acid 
During the spring of 1923 investigations involving the use of liquid 
hydrocyanic acid were undertaken and very detailed and thorough box 
experiments were first conducted which were later followed by green- 
