94 FUMIGATION METHODS 



fumi gator is employed, however, this difficulty is over- 

 come, as the cubic content is constant and the amount 

 of chemicals used does not vary. The danger of error 

 is eliminated when a box or house is used. It matters 



FIG. 47 BOX USED BY SOME NURSERYMEN IN THE SOUTH 

 (AFTER SHERMAN) 



not whether one or several thousand trees are placed 

 in the enclosure, the amount of gas generated must re- 

 main constant. 



Small boxes. Many nurserymen find small boxes 

 very useful. Fig. 47 is a box used in North Carolina. 

 The details for construction are given by Prof. Frank- 



