TESTING THE VALUE OF FUMIGATING AGENTS 



there is three inches' overlapping of the door and window upon the 

 framing, to minimize the loss of fumigant. In actual practice we 

 have found the leakage from this source is practically nil. 



The small door in the back, measuring one foot square, is so 

 arranged that one may paste paper or any fabric over the opening 

 in such a way as to determine its permeability to a given fumigating 

 agent. It is frequently necessary to do this, particularly if one 

 wishes to know the value of such material when employed for closing 



BACK Fig. 4. 



FIG. 4. Back view of box. 



FIG. 5. Closing device for door; the overlapping is the same as the front door. 



openings in buildings which are to be fumigated. The function of 

 the glass windows, each one foot square, upon the sides, has already 

 been commented upon. 



Holes measuring one and one-half inches in diameter are bored 

 at regular intervals through the bottom, top, sides, front, and back 

 of the box. Particular attention is paid to have the alignment 

 with reference to the height above the floor exact, because the dis- 

 tance above the floor is a very important factor to consider with 

 many fumigating substances, particularly if the fumes are light, 

 and consequently very dense at the top of the room, but practically 



