25 Texas AGRICULTURAI. EXPERIMENT STATIONS. 
apidly, and this gas, or vapor, is a little more than two and one-half 
times as heavy as air. This is a point to be remembered in its use, since 
it goes first to the bottom of whatever it is confined in. When mixed 
with air it becomes highly inflammable and sometimes explosive. Such 
a mixture of air and bisulfide gas may be exploded by even a spark, such 
as might be made by hitting a nail with a hammer. The liquid, on 
evavoration, leaves a residue of impurities. Its rate of evaporation is In 
proportion to the temperature and the area of the exposed surface. Its 
efficiency is greatest with rapid evaporation, and this is secured in rela- 
tively warm weather, but artificial heat must never be used to hasten its 
change into gas. Carbon bisulfide is obtainable from practically every 
druggist. 
When carbon bisulfide is to be used for fumigation of infested material, 
the greatest precaution should be used to keep all fire, such as lights, 
‘cigarettes, etc., away from the liquid and where it is being used. For 
this reason it is well to take the material that is to be fumigated to.some 
place out of doors and at least a liundred feet away from any building. 
The infested material should be placed in supers or hive-bodies if possible. 
These are piled as high as is convenient and all cracks between the supers 
made as nearly gas-proof as possible. Especially should the bottom be 
tight. A good plan is to place an inverted hive cover on the ground, lay 
a piece of canvas over it, and then tier up the supers on this. After the 
pile has been completed, an emptv super should be put on top. In this 
should be placed a large shallow pan into which the bisulfide is to be 
poured. ‘When all is in readiness, pour the bisulfide into the pan and 
immediately put a hive cover on the top of the tier to confine the gas. 
This operation is best performed in the evening and the pile of supers 
should be left intact until the following morning. When the supers are 
taken down the confined gas will escape from them immediately, even 
before they can be carried, separately, into a building. 
The results of fumigating infested material with carbon bisulfide is 
shown in the following table: 
