190 FUMIGATION METHODS 
cubic feet capacity, of which the horizontal dimensions 
were 13% feet by 1% feet and the vertical 114 feet. 
The experiments covered five different cases, and it 
appears first that there is less uniformity than with 
the box of 60 cubic feet. This may be due, and prob- 
ably is in part, to the structure of the two boxes, the 
former having rawhide roofing paper sides and the 
latter double sides with paper lining. Hence in the 
case of the box under discussion outside disturbing 
influences may have been felt to a greater degree. 
‘‘ With the intake at the same end of the box as 
the generator, after three minutes’ diffusion time there 
appeared in a single instance a deficit of acid vapor as 
compared with the normal, in two other instances a 
considerable excess. The extreme fluctuations found 
show forcibly the inconstancy of spontaneous diffusion, 
especially with this arrangement and after a short 
interval of time. With the generator at the middle of 
the box and the intake at the end there is greater uni- 
formity and after ten minutes a considerable deficit, 
which deficit remains practically the same for a half 
hour ; the amount of vapor then gradually diminishes, 
doubtless through leakage. It appears then that of 
these two arrangements, viz., the generator in one 
case at the end of the box and again in the middle, 
the latter gives more uniform results and also a more 
even distribution of the acid vapor. This is, perhaps, 
what would be expected, but it must be noted that 
even in the latter case the quantity of vapor in one 
instance is double what it is in two other instances. 
‘“In summary, then, be it noted of these cases of 
spontaneous diffusion that within a half hour of diffu- 
