10 
suspension better. Arsenate of soda costs wholesale about 10 cents a 
pound, and first-class acetate of lead about 10 cents a pound. 
Arsenate of lead may be used at any strength from 3 to 15 pounds’ 
to 100 gallons of water without injury to the foliage, for the reason 
that it contains little, if any, soluble arsenic. It is ordinarily used 
at the rate of 4 to 6 pounds to the 100 gallons of water or Bordeaux 
mixture. In later years it has come into general use, especially for 
spraying plants sensitive to arsenical poisoning, such as peach, and 
also in cases where it is necessary to make heavy applications. Its 
safety as regards the burning of foliage and its adhesive quality 
offset its greater cost, and it is now much used in the codling moth 
work and general arsenical spraying. 
In the home preparation of this arsenical, the number of pounds 
of the poison per 100 gallons of water as given in directions for use 
should be understood to mean the combined weights of the two 
ingredients. In point of fact, the resulting lead arsenate is only 
about half the actual weight of the two ingredients, which explains 
in part the apparently excessive amounts used as compared with 
other arsenicals. 
A good many brands of arsenate of lead can be purchased on the 
market, usually in the form of heavy pastes. As already indicated, 
they have not the same power of remaining in suspension as the 
freshly made product, but are otherwise, if properly made, quite 
satisfactory. The water content, which is variable, should be spe- 
cifically indicated and guaranteed, to make it possible to use the 
poison at the strength desired. 
Arsenite of lead is a compound very similar to the arsenate of lead, 
but it contains a less percentage of arsenic. It is prepared from 
sodium arsenite. 
General considerations.—In point of solubility and corresponding 
danger of scalding the foliage, these arsenicals fall in the following 
order, the least soluble first: Arsenate of lead, arsenite of lime, Paris 
green, copper arsenite, and London purple. In point of cost the 
arsenite of lime is much cheaper than the other arsenicals, and the 
arsenate of lead, at the rate at which it is necessary to use it, much the 
most expensive. But after all the main cost is in the application, 
and it is therefore well worth while to secure a good arsenical and 
get the best results. 
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. 
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