2990 Rerort OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
The fumigators used in our experiments were provided with smal} 
windows, one on either side, so that the bag could be watched as 
it fell into the acid and the action of the acid noted. 
During some of our experiments the strips of canvas at the 
base of the fumigator were covered with dirt, as shown at Plate 
XLVI. This method was finally discarded and bags half full of 
sand substituted, as they were found to be more easily handleg 
and equally effective in making the base of the fumigator tight. 
A stout water-proof bag 6 feet long and of small diameter, two- 
thirds full of sand, will be found convenient for this purpose. 
Four would be required for each fumigator and could be handled 
easily. 
The time required for moving the fumigator from one tree to 
another and putting it in place will vary somewhat; but in our 
experiments in an orchard of standard Bartlett pear trees two 
men moved the fumigator from one tree to another and set it up 
in ten minutes without unusual effort. 
SOME ADVANTAGES OF THIS STYLE OF FUMIGATOR. 
There are at least four advantages over the tent and its modi- 
fications which may be claimed for this style of fumigator. 
1. Its cubic contents can be accurately computed, thus ensur- 
ing correct treatment with the gas. 
2. The same amounts of chemicals are used for each charge, 
thus avoiding the necessity of changing the amount for each 
tree, and of weighing cyanide in the field, which usually requires 
an extra man where three or four fumigators are in operation. 
The slight cost of chemicals that might be saved on trees not 
large enough to fill the fumigator is immaterial unless the trees 
are very small. In such cases, if there are many of them, a fumi- 
gator of smaller size could be used. 
3. Fewer men are required to handle it than would ordinarily | 
be required to handle a tent large enough to cover trees that can 
be treated with the size of fumigator described. 
4. As the fumigator does not rest upon the tree there is little ~ 
if any danger of serious injury to buds or breaking of small limbs. 
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