98 
ORCHARD MOTH CATERPILLARS. 
In order further to remove risk from inhaling dust in process of 
mixing, Messrs. Blundell & Spence arranged that where wished they 
would slightly moisten the powder before forwarding it to the 
purchaser; this is the form known as “ Paris-green paste,” which is 
mentioned in the recommendations of the Experimental Committee. 
In use, the above directions should be followed; in fact, ordinary 
care and caution should be used; like others of the poisons which are 
used in various agricultural treatments, Paris-green may be used 
without the slightest danger or damage if reasonable care is taken ; 
if not, there is necessarily a possibility, in this as in other cases, of dis¬ 
agreeable effects or dangerous illness ensuing, or possibly death. 
The cost of the Paris-green is very little .—The firm with whom I 
have corresponded on the subject inform me that, as wholesale 
manufacturers, they could furnish quantities of 1 cwt. and over, at the 
rate of lOd. per lb. Retail traders would probably not furnish the 
pure article under Is. 3d. per lb. 
In the use of Paris-green as a fluid dressing , or spray, one of the 
first points to be borne in mind is that this chemical does not dissolve 
in water. It is simply held in suspension. The powder merely mixes 
with the water, and unless this mixture is kept stirred, the Paris-green 
powder will sink to the bottom of the barrel, pump, or other apparatus, 
instead of beiug evenly distributed throughout the fluid. 
For this reason it is necessary to keep the mixture in agitation 
during application, and also it is necessary to have the barrel “ well 
washed out after it has been filled ten or twelve times.” If this is not 
done the mixture will very soon be too weak at the top and too strong 
at the bottom, and the gradually increasing settlement will presently 
(in all probability) cause a seriously too strong overdose. 
One great point therefore, in selection of spraying machines, is that 
either by mechanical contrivances (when on a large scale), or in the 
portable forms by arrangements which will make the movement of the 
bearer serve the same purpose, the mixture should be so kept in 
movement that the powder should not settle down. The mixture 
should be kept at an even strength throughout, during the whole time 
of distribution, and also it should be so distributed that it will be 
thrown as a fine spray, or mist, and will rest and remain both on the 
upper and under sides of the sprayed leafage as a fine film or dew. 
It should on no account whatever be thrown so as to “ swill ” or 
“ souse ” the trees, and run off the leaves in drops, or streams ; this is 
bad practice in every way. It uses a great deal more of the chemical 
than is needed; the leaves get little but pure water at their highest 
part, and much too strong application where the fluid has settled at 
the tips; and also a drip is caused on to the ground beneath, which # 
may render the grass temporarily poisonous, 
