THE HALL SCALE ERADICATION PROJECT ila? 
Figure 7.—A, covering a tree; B, removing the tent from a fumigated tree. 
The tents were made of cloth with a plastic coating. The first tents did 
not remain gastight through one season. A local coating firm assisted in 
developing a mixture that could be applied with a brush each year. With 
the cooperation of several coating companies tents were gradually improved, 
as shown by the following average gas losses between 5 and 40 minutes 
after introduction of the gas: 
Percent 
NOAG Ay eens eee ee ees 5D) 
NOAH 4 Cie eree iy were a ek DO 
OA BAO Rake ora anon Meee er cote eas | 
HOAO= | ONAG eet ere ee ee oes oO) 
NOD OR ee ee et ae eee aye EEO, 
