6 
than any of the other poisons. Bought wholesale, the acetate of lead 
costs about 74 cents a pound, and the arsenite of soda 5 cents a pound. 
It may be used at any strength from 3 to 15 pounds to the 100 gallons 
of water without injury to the foliage, and in this respect is much safer 
on delicate plants than any other arsenical. Its use is advised where 
excessive strengths are desirable or with delicate plants where scalding 
is otherwise liable to result. 
In point of solubility and corresponding danger of scalding the 
foliage these arsenicals fall in the following order, the least soluble 
first: Arsenite of lead, Paris green, Scheele’s green, and London purple. 
The difference between the first three is not great in the particulars 
noted nor also in point of effectiveness against larvie or other insects. 
London purple is ordinarily considerably less effective. 
HOW TO APPLY ARSENICALS. 
There are three principal methods of applying arsenicals. The wet 
method, which consists in using these poisons in water in the form of 
spray, is the standard means, secures uniform results at least expense, 
and is the only practical method of protecting fruit and shade trees. 
The dry application of these poisons in the form of a powder, which is 
dusted over plants, is more popular as a means against the cotton 
worm in the South, where the rapidity of treatment possible by this 
method, and its cheapness, give it a value against this insect, in the 
practical treatment of which prompt and economical action are the 
essentials. This method is also feasible for any low-growing crop, such 
as the potato, young cabbages, or other plants not to be immediately 
employed as food. The third method consists in the use of the arsen- 
icals in the form of poisoned baits, and is particularly available for such 
insects as cutworms, wireworms, and locusts in local invasions. 
The wet method.—Hither Paris green, Scheele’s green, or London pur- 
ple may be used at the rate of 1 pound to 100 to 250 gallons of water, 
or 1 ounce to 6 to 15 gallons. The stronger mixtures are for such vig- 
orous foliage as that of the potato for the Colorado potato-beetle, and 
the greater dilutions for the more tender foliage of the peach or plum. 
An average of 1 pound to 150 gallons of water is a good strength for 
general purposes. The poison should be first made into a thin paste 
in a small quantity of water and powdered or quick lime added in 
amount equal to the poison used to take up the free arsenic and remove 
or lessen the danger of scalding. An excess of lime will do no injury. 
The poisons thus mixed should be strained into the spray tank or res- 
ervoir, care being taken that all the poison is pulverized and washed 
through the meshes of the strainer. The use of the lime is especially 
desirable in the case of the peach and plum, the foliage of which, par- 
ticularly the former, is very tender and easily scalded. To the stronger 
foliage of the apple and most shade trees Paris green may be applied 
without danger at the strength of 1 pound to 150 gallons of water; 
with London purple it is always better to use the lime. 
