96 
ORCHARD MOTH CATERPILLARS. 
4 
given to all who were inclined to think that if good was done by a weak 
application much more would be done by a strong one, and where over¬ 
doses took place (without accidental help from rainfall), injury 
followed. 
The only point which has come under my notice in the enormous 
quantity of reporting sent to my hands on the subject, that does not 
appear as yet to be quite clear is whether bright sunshine soon after 
spraying does or does not cause it to have some degree of injurious 
effect. In the coming season when we may have the benefit of 
apparatus to throw the fine hazy moisture in the proper manner, this 
difficulty will probably vanish. 
But we have now proof from thoroughly publicly tried experiments 
on a working scale, that here, as in America, when properly applied 
the Paris-green mixture will kill the caterpillars without injuring the 
leafage; that these operations have been followed by an exceedingly 
good harvesting of fruit, and this again by a good promise for next 
year by the amount of forming buds on the trees, and by notable 
diminution of Winter Moth appearance in autumn. 
Our experiments have been mainly directed to, and the reports mainly 
concern, Paris-green. Though some observers have experimented and 
thought well of the arsenical preparation known as London-purple, 
in these notes and recommendations, I have strictly limited myself 
to Paris-green, which I can give evidence of successful use of, from 
the Government reports of the United States and Canada, and of 
publicly tried and tested experiment here.* 
Nature of Paris or Emerald-green, and cautions requisite to be 
observed in its use .—“ Paris-green ” is an aceto-arsenite of copper, and 
of a poisonous nature, and therefore should be used with care in 
mixing, and should not be applied to fruit or to vegetables that are used 
for food. But, as will have been seen in the previous observations, the 
quantity to which it, in order to be beneficial, is requisite to limit 
application in spraying for prevention of moth caterpillars (see p. 86) 
is excessively small, and our English experiences of the past season, 
as well as those on the Continent of America where Paris-green has 
been used regularly in farm and orchard prevention for many years, 
show that with proper care it may be used with perfect safety. 
On application to Messrs. Blundell & Spence, of Hull, as being 
well known manufacturers and great exporters of Paris-green, for 
information as to the precise constituents of this chemical, and the 
different names under which it was described, Mr. E. Dixon (Manager) 
replied to me as follows :—“ Emerald-green, Paris-green, Schweinfurtli- 
green, are different names for the same thing. The first name is 
* For paper on nature and serviceableness of London-purple see Index. 
