'Mveeyil" tx PtRaix. 169 



however, soon passes away." At ordinary temperature it 

 vaporizes rapidly, forming a heavy gas, which is highly 

 inflammable and a powerful poison. 



Ap])lication. — It may be apj)lied directly to the infested 

 grain or seed without injury to its edible or germinative 

 principles by spraying with an ordinary watering-can 

 having a fine rose nozzle. In moderately tight bins it is 

 more effective, however, evaporating more slowly and 

 diffusing more evenly, if placed in shallow dishes or pans, 

 or on bits of cloth or cotton waste distributed about on 

 the surface of the grain or infested material. The liquid 

 volatilizes rapidty, and, being heavier than air, descends 

 and permeates the mass of grain, killing all insects and 

 other vermin present. 



Amount to Use. — The bisulfide 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 one to 

 three pounds to 100 bushels 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. Bins may be rendered 

 nearly air-tight by covering with cloths, blankets, or 

 canvas. 



The amount of bisulfide to be used depends very largely 

 upon the shape of the space to be fumigated. If the grain 

 is in approximately a cubical form, the above amounts will 

 be sufficient; but if spread out with but little depth, two 

 to four or five times as much will be found necessary. 



Time to Fumigate. — '^Infested grain is generally sub- 

 jected to the bisulfide treatment for twenty-four hours, but 

 may be exposed much longer without harming it for mill- 

 ing purposes. If not exposed for more than thirty-six 



