326 
the largest tree subjected to the gas I used 18 ounces of the cyanide 
and the other ingredients in their proper proportions, employing the 
2-gallon jar for a generator, and this was large enough, to contain the 
chemicals during the process of generating the gas. 
Altogether, I treated 326 trees and shrubs with this gas ; these are as 
follows: pear, 187: apple, 8; quince, 4; plum, 24; peach, 13; cherry, 22; 
gooseberry, 17; currant, 9; JEleagnus longipes, 5; rose, 25 and lilac, 12. 
After the tent was placed on a tree and charged with the gas it was 
allowed to remain on the tree for half an hour. Four men could remove 
the four tents from the trees, place them over others, and charge them 
with gas in from fifteen to twenty minutes, according to the size of the 
trees. Six tents could easily have been operated by this number of 
men without any loss of time, since the tent first placed over a tree 
would be ready for removing by the time that the last tent was charged 
with the gas. This would result in treating twelve trees an hour, but 
in the case of small trees and shrubs several of these could be treated 
at a time by one of the tents. 
The chemicals used in this work were furnished the Division by one 
of the druggists of this city — the potassium cyanide at 60 cents per 
pound and the sulphuric acid at 3£ cents per pound. It is worthy of 
note that the fruit-growers of Southern California obtain this same 
brand of cyanide (Powers and Weightman's 58 per cent fused) at 39 
cents per pound, and that, too, after paying the freight on it almost 
across the continent. About 42 pounds of the cyanide and 90 pounds 
of the acid were used in treating the 326 trees and shrubs above 
mentioned. Assuming that the cyanide could be obtained at the same 
price that it can in California, that the four men could be employed at 
$1 per day, and that they could treat an average of twelve trees an 
hour, working ten hours a day, gives us the following as the probable 
cost of treating the 326 trees and shrubs mentioned above : 
42 pounds cyanide, at 39 cents per pound. $16. 38 
90 pounds sulphuric acid, at 3+ cents per pound 3. 15 
4 men 2£ days, at $1 each per day 10. 66 
Total $30.19 
This is an average of slightly over 9 cents for each of the 326 trees 
and shrubs treated with the gas. 
It was anticipated that considerable difficulty would be experienced 
in operating the tents on the leafless trees, which are so different from 
the Citrus trees, upon which this treatment has been principally per- 
formed in the past; but, with the exception of some large pear trees, 
the branches of which were more rigid and brittle than those of the other 
trees, but little trouble was experienced in this direction. It was 
found expedient to draw the tents off of the trees in the same direc- 
tion that they were drawn on ; any attempt at taking them off in an 
opposite direction is almost certain to result in the breaking of the 
branches. 
