8 
green and arsenate of lead, are less known and not so easily obtainable, 
but in some respects are better than the first-mentioned poisons, as 
will be shown later. The use of powdered white arsenic is not recom- 
mended, on account of its great liability to scald foliage, as well as for 
the fact that it is apt to be mistaken for harmless substances. The 
arsenicals mentioned have the following characteristics: 
Paris green is a definite chemical compound of arsenic, copper, and 
acetic acid (known as the aceto-arsenite of copper), and should have a 
nearly uniform composition. It is a rather coarse powder, or, more 
properly speaking, crystal, and settles rapidly in water, which is its 
greatest fault. Its excessive cost, about 20 cents a pound, is due to 
its being crystallized with acetic acid, making it a more brilliant pig- 
ment, but giving it a coarse grain and rendering it a much poorer 
insecticide. 
Scheele’s green is similar to Paris green in color, and differs from it 
only in lacking acetic acid; in other words, it is a simple arsenite of 
copper. It is a much finer powder than Paris green, and therefore 
more easily kept in suspension, and has the additional advantage of 
costing only about half as much per pound. When properly washed 
and prepared by the manufacturers it is less harmful to foliage even 
than Paris green, is quicker in effect, and should supplant the latter as 
an insecticide. It is used in the same way and at about the same 
streneth as Paris green and London purple. 
London purple is a waste product in the manufacture of aniline dyes 
and contains a number of substances, chief of which are arsenic and 
lime. It is quite variable in the amount of arsenic and is not so 
effective as the green poisons and is much more apt to scald unless 
mixed with lime. It comes as a very fine powder, and is more easily 
kept in suspension than Paris green. It costs about 10 cents a pound. 
Arsenate of lead is prepared by combining, approximately, 3 parts 
of the arsenate of soda with 7 parts of the acetate of lead (white sugar 
of lead) in water. These substances when pulverized unite readily and 
form a white precipitate, which is more easily kept suspended in water 
than any of the other poisons. Bought wholesale, the crystallized 
acetate of lead costs about 74 cents a pound (or the uncrystallized 
brown sugar of lead, 5 cents), and the arsenate of soda 5 cents a pound. 

small gardens, but is too expensive for large operations. It kills insects in the same 
way as the arsenicals, as an internal poison, and is less dangerous to man and the 
higher animals; but if sufficient be taken it will cause death. It is particularly 
effective against the larvee of sawflies, such as the cherry slug, rose slug, currant 
worms, and strawberry worms. 
It may be applied as a dry powder, preferably diluted with from 5 to 10 parts of 
flour, and dusted on the plants through a muslin bag or with powder bellows. The 
application should be made in the evening, when the plants are moist with dew. 
Used as a wet application, it should be mixed with water in the proportion of 1 
ounce to the gallon of water and applied as a spray. 
meee 
