72 
ORCHARD INSECTS. 
With regard to depth of tint, Mr. Dixon added that:—“ Colour alone 
is not an all-sufficient test. To a small extent the dark shade may be 
reduced with aniline green, and, in the matter of judging colour, all 
are not equally proficient. Though not met with in trade, an emerald- 
green can be made very much paler than the palest sample we sent 
you, and still he pure. We send you a sample of the palest pure we 
have ever made; for your purpose this might be the best.”—J. D. 
With regard to methods of distribution. — So far as I am aware, 
the best method of distributing the fluid application in the fine even 
spray which is desirable would be by means of the Strawsonizer set to 
have a vertical action, or by throwing it from some of the washing- 
engines so high that it might fall again in a gentle spray. For more 
complete work, such insecticide appliances as those known as the Riley 
or Cyclone nozzle used in America, or the modifications of them which 
could be fully as well made by our own as by continental firms, would 
in the end be probably by far the best. 
The subject was first brought forward by Prof. Riley (now Ento¬ 
mologist of the Department of Agriculture of the United States of 
America), at the National Congress of the United States in 1872, as a 
likely means of destroying the “Cotton-worm” (the caterpillar of a 
moth which causes great injury to the Cotton-crops), and the results 
of trial fully realized his expectations *; but the great success which 
brought Paris-green before the American agricultural public, and gave 
it a place as a serviceable insecticide, which it has held ever since, was 
its effect, when other special measures failed, in destroying the hordes 
of the Colorado Potato-beetle, “which were invading and threatening 
the entire ruin of every Potato-field throughout the Northern and 
Middle United States east of the Rocky Mountains, and southward 
into North Carolina, and Northern Texas.Paris-green is a 
a combination of arsenic and copper. .... In its pure state it 
contains fifty-eight per cent, of arsenic (arsenious acid).” f 
In Dr. Lintner’s paper, quoted above, some of the results are also 
given of the series of experiments undertaken officially by Dr. William 
M‘Murtrie as Chemist of the United States Department of Agriculture, 
in order to ascertain the effects of Paris-green on soil and the plants 
grown therein. Of these the following are of importance with regard 
to some of the ordinary objections made to the use of Paris-green :— 
Dr. Lintner notes :—“ The results obtained were these :— 
“1. An aggregate of 906.4 pounds of Paris-green per acre must be 
applied before any injurious effects on plant-growth | are appreciable. 
* ‘ Eighth Annual Report of the Noxious Insects of the State of Missouri,’ by 
C. V. Riley, State Entomologist. 
t ‘First Annual Report of Injurious, &c., Insects of the State of New York,’ by 
Dr. J. A. Lintner, State Entomologist, 1882, p. 26. 
\ This, it will be noticed, refers to growth, not to effect when applied on leafage. 
