LEAD ARSENATE

Pbs (AsO.)2 sometimes known as gypsine because he it was used to exterminate the caterpillar of the gypsy moth. Occurs as white crystals or as a paste, An exceedingly poisonous corapound widely used in solution for spraying trees and plants to destroy insects and caterpillars, for which purpose it is often mixed with jime or sulphur. It is preferred to other poisons because it causes very little d|leaf scorching. It is prepared by adding a, solution containing 7 oz. of lead acetate to a solution containing 2 oz. of dry, or 3 oz. of crystallized, sodium arsenate. For use as a spray, the mixture is diluted to ten gallons. Lead nitrate may be used in place of the acetate, the resulting compound then haying the formula