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being heavier than air descends and permeates the mass of grain, kill- 
ing all insects and other vermin present. 
The bisulphide is usually evaporated in vessels containing one-fourth 
or one-half of a pound each, and is applied in tight bins at the rate of 
a pound to a pound and a half to the ton of grain, and in more open 
bins a larger quantity is used. For smaller masses of grain or other 
material an ounce is evaporated to every 100 pounds of the infested 
matter. Binsmay be rendered nearly air-tight by covering with cloths, 
blankets, or canvas. 
Infested grain is generally subjected to the bisulphide treatment for 
twenty-four hours, but may be exposed much longer without harming 
it for milling purposes. If not exposed for more than thirty-six hours 
its germinating power will not be impaired. In open cribs and badly 
infested buildings it may sometimes be necessary to use a double quan- 
tity of the reagent and repeat treatment at intervals of about six 
weeks during the warmest weather. 
Mr. H. E. Weed, entomologist of the Mississippi Experiment Station, 
claims that 1 pound to 100 bushels of grain is amply sufficient to 
destroy all insects, even in open cribs. 
Mills and other buildings, when found to be infested throughout, 
may be thoroughly fumigated and rid of insects by a liberal use of the 
same chemical. A good time for this work is during daylight on a 
Saturday afternoon or early Sunday morning, closing the doors and 
windows as tightly as possible and observing the precaution of station- 
ing a watchman without to prevent anyone from entering. It is best 
to begin in the lowest story and work upward, to escape the settling 
gas. The building should then be thoroughly aired and the grain 
stirred early Monday morning. 
For the fumigation of a building or a reasonably close room it is 
customary to evaporate a pound of the bisulphide for every thousand 
feet of cubic space. In comparatively empty rooms, and in such as do 
not admit of being tightly closed, two or three times the above quantity 
of the chemical is sometimes necessary. 
Certain precautions should always be observed. The vapor of 
bisulphide is deadly to all forms of animal life if inhaled in sufficient 
quantity, but there 1s no danger in inhaling a small amount. The 
vapor is inflammable, but with proper care that no fire of any kind, as, 
for example, a lighted cigar, be brought into the vicinity until the 
fumes have entirely passed away, no trouble will be experienced. 
Bisulphide of carbon retails at from 20 to 50 cents a pound, but at 
wholesale, in 50-pound cans, may be obtained for 10 cents a pound. A 
grade known as “fuma bisulfide,” for sale at the latter price, is said to 
be more effective than the ordinary commercial article. 
At the rate used the cost of treatment is from 10 cents and upward 
for each ton of grain. 
