A METHOD OF FUMIGATING SEED. 3 



When this apparatus is used for fumigation, the seeds, contained 

 in either a cloth bag or an open vessel, are placed in the chamber, and 

 the requisite amount of sodium or potassium cyanid in a small 

 beaker is so arranged that the neck of the dropping funnel extends 

 down into the beaker (fig. I,/). The cover is then clamped on and 

 the chamber exhausted. In extracting the air from the chamber, the 

 suction is continued until the gauge registers 30 inches or more 

 that is, the air in the chamber is exhausted until the pressure is the 

 equivalent of some fraction of an inch of mercury. The suction 

 is then cut off by means of the gas cock, and the required quantity 

 of diluted acid, which has been previously placed in the bulb of the 



FIG. 2. Air pump (a) and fumigation chamber (6) used in the experiments described in this bulletin. 



dropping funnel, is allowed to flow slowly upon the cyanid in the 

 beaker within the chamber. The hydrocyanic acid is thus prepared 

 in the chamber and no trace can get out. After the seeds are exposed 

 to the gas for the required time, the stopcock of the dropping fun- 

 nel is opened to let the air into the chamber. As the discharge 

 pipe of the air pump extends outside the building, the mixture 

 of hydrocyanic acid and air can not escape into the room. As 

 soon as convenient, the stopper and funnel are removed and, by 

 means of the air pump, air is sucked through the chamber, thus 

 washing the hydrocyanic acid out of the chamber .before the cover 

 is taken off and the seeds removed. In the experiments described 



