A METHOD OF FUMIGATING SEED. 3 



Wten this apparatus is used lor fumigation, the seeds, contained 

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

 the requisite amomit of sodium or potassium cyanid in a small 

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

 dowii into the beaker (fig. 1,/). The cover is then clamped on and 

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

 suction is continued mitil the gauge registers 30 inches or more — 

 that is, the au' 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 



Flo. J. -Ail ;.ui;i 



jii 1 (iimig.iiioii chainiicr ih) ased in (he exppiimenls described in this bulletin. 



<lropping furuiel, is allowed to flow slowly upon the cyanid in the 

 beaker witliin the chamber. Tlic 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 i.s opened to let the air into the chand)er. As the discluuge 

 pipe of the air puni]) extcuids outside the l)uil(ling, i\w. mixture 

 of hydrocyanic ac^id and air can not e.scajxi into the room. As 

 soon a.s convenient, th(? stopper and funnel ar(^ removed and, by 

 means of the air pump, air is sucked ihrougli llie chamber, thus 

 washing the liydrocyanic acid out of tlic chamber before the cover 

 is taken off and the seeds removed. In Ihc experiments descnbed 



