3D 
Size of tree.; 
Cyanide of 
potassium. 
Bicarbon- 
ate of 
soda. 
Sulphuric 
acid. 
Feet. 
Fluid ozs. 
Founds. 
Fhiid ozs. 
4 
. 7 
.05 
.4 
5 
1.6 
. 11 
.3 
6 
2.5 
. 20 
1.3 
7 
4. 0 
. :9 
2. 1 
8 
6. 0 
.44 
3.1 
9 
8.5 
.63 
4. 5 
10 
11.5 
.><7 
6.2 
1L 
15. 5 
1. 14 
8.2 
12 
20. 0 
1. 50 
11.6 
13 
25.4 
1.90 
13.5 
14 
31.6 
2. 50 
16. 6 
15 
39.2 
2. 92 
20.7 
16 
47.5 
3. 55 
25.2 
17 
57.5 
4. 23 
30. 1 
18 
67.7 
5. 05 
35.8 
19 
70.9 
5. 93 
42.1 
20 
90.5 
6. 93 
49.2 
In order to apply the doses easily they are prepared so that the re- 
quired amounts of each ingredient can be directly measured. The cyan- 
ide solution is prepared by dissolving, say, 10 pounds of the solid salt in 
about 2J gallons of water, warmed nearly to the boiling point, stirring 
at intervals, cooling, and then diluting to 2J gallons. This solution 
will contain about one ounce of cyanide of potassium to 2£ fluid ounces 
of the liquid. 
The bicarbonate of soda is pulverized finely and measured off in a 
vessel marked, so as to designate pounds and fractions of a pound of 
the solid material. It is then placed in the generator, and the dose of 
cyanide mixed with it, and, if necessary, a little water added to make 
it into a thin paste. After adding the measured dose of sulphuric acid, 
the pump is worked slowly at first, and moie rapidly after the gas has 
passed into the tent. The time for each treatment must be determined 
by future experiments j fifteen minutes seemed to be quite sufficient 
when the cyanide alone was used, but it may be desirable to extend the 
treatment to thirty minutes when the foliage is protected by the car- 
bonic acid gas. 
It is advisable that the treatments should follow cultivation after 
about four days, so that all weeds and places where the insect may find 
lodgment would be destroyed. The insect will then be on, or very near, 
the tree ; the fitting of the tent to the ground is thus also much easier. 
The eggs of the insect remained apparently uninjured wherever pro- 
tected by the woolly covering. A second treatment, to destroy such as 
may afterward hatch, will, therefore, be necessary. 
It must not be understood that these experiments definitely settle the 
mode of operation and the size of the doses to be used. They are merely 
suggestive of a general plan which can be so perfected in the future that 
the application of this remedy to other kinds of trees and insects must 
be attended with good results. It simply remains for the ingenious cul- 
tivator to devise the necessary appliances for its use, on a small scale, 
on all sorts of fruit trees, shrubs, and plants. 
