12 FUMIGATION OF APPLES FOR SAN JOSE SCALE. 
(fig. 1, box C), against wien it was tightly ppeeced by the six 
Ceiaps to each Ko (fig. 1, box E; fie? 7 1G) 
To permit quick tea of gas at cts of period of exposure, 
each box was supplied on lower rear side and at top with a 2-inch 
pipe opening and a tight valve, the lower series (fig. 1, Sa) con- 
necting with the common outlet pipe (8), extending to the outside 
of the building and opening above the level of the roof, the upper 
series (Sa) joined to a pipe (5), connected with the electric blower 
(6), for generating the air blast. This arrangement permitted the 
simultaneous clearing out of the gas in all of the boxes, or one or 
more boxes could be operated independently of the others. About 
fifteen minutes were required to clear the boxes of gas, though this ~ 
was of course greatly diluted with fresh air almost immediately 
after the blower was put in operation. 
To insure a uniform distribution of gas in the boxes from the 
start, a small generating box was constructed and placed on the 
floor at about the center, as shown in detail in figure 2, A, B, 3 a—d. 
This box, except as noted, was fairly tight, with a door in front 
for introducing the chemicals and four square hollow arms with the 
ends open and seven 4-inch holes along each side. A shaft of heavy 
steel wire extended from side to side in the upper part of the box, 
projecting on one side in the form of a crank. A small metal cup 
was rigidly attached to the middle of the wire shaft to receive the 
potassium cyanid (fig. 2, A, 5b). Beneath the cyanid cup was space 
for the introduction of a small jar containing the necessary sulphuric 
acid and water (3c). A string was attached to the crank end of 
the shaft bearing the cyanid cup, by means of which the cup could 
_ be inverted and the cyanid thus dropped into the jar beneath. With 
the door of the generating box closed, the gas was mostly forced 
out through the four arms, insuring a fairly uniform distribution 
from the moment the chemicals were brought together. 
A heavy slat platform (fig. 2, A, 2) was provided somewhat 
above the generating box, and on this were placed all packages of 
fruit to be treated, as barrels, baskets, boxes, etc. The apparatus 
as described proved well suited for the work in hand, and it is 
believed was as tight as it was practicable to make it. At no time 
during fumigation could the odor of escaping gas be detected at 
cracks or around the door, though the gas was forced out into the 
room to some extent when the air blast was turned on. 
In the operation of fumigation the two valves of a box were 
first closed, the package of fruit to be fumigated placed on the slat 
platform, the weighed cyanid lightly wrapped in tissue paper, put 
into the cyanid cup, and just before closing the fumigating box the 
jar of measured acid and water was inserted into the generating box 
