218 FUMIGATION METHODS 
The front of the fumigator can be opened as a doubie 
door of a width equal to the shortest diameter of the 
box. Unbleached sheeting so treated as to be gas- 
tight is used asa cover. Careful tests ‘with this fumi- 
gator showed that it was practically gas-tight. 
Fumigation of orchard trees near Albany.—A series 
of tests were made by Dr. E. P. Felt, State Entomol- 
ogist, in the spring of 1900, with hydrocyanic acid gas 
for the purpose of ascertaining its efficiency and prac- 
ticability in the latitude of Albany, N. Y. A canvas 
tent 6x6x 8 feet with a fixed pyramidal hood 7 feet 
high, as shown in Fig. 81, was constructed of eight- 
ounce duck thoroughly oiled with boiled linseed oil. 
The rectangular part of the tent was supported on a 
light wooden frame, to reduce the variation in cubic 
contents as much as practicable. ‘The tent was lifted 
with a thirty-foot pole and eight-foot gaff, and thus 
dropped over the tree. The hood was kept extended 
during the process of fumigation, as shown in the fig- 
ure, illustrating also the manner of guying the pole 
and tent. The tent and apparatus for handling it cost 
about $38, but they could undoubtedly be made for less 
when several were needed. A good pole and gaff from 
near-by woods could be gotten at little expense. The 
bottom of the tent was provided with what Dr. Felt 
calls a ‘‘sod cloth.’’ It consists of a flap six to eight 
inches wide, which was covered with earth to prevent 
the escape ofthe gas. An uncovered space was always 
left on the windward side for. the insertion of the 
chemicals. The trees in these tests were exposed to 
the gas for 35 minutes. After fumigation the guy- 
lines were released, the sod cloth uncovered, and the 
