INSECTICIDES. 3 



PARIS GREEN. An aceto-arsenite of copper. When pure, 

 it contains about 58 per cent of arsenic ; but the commer- 

 cial article usually contains less often as little as 30 per 

 cent, and rarely none. The following may be considered 

 an average analysis : Arsenic, 47.68 per cent ; copper oxide, 

 27.47 ; sulphuric acid, 7.16 ; moisture, 1.35 ; insoluble resi- 

 due, 2.34. It is applied in either a wet or dry condition ; 

 but in any case, it must be much diluted. For making a 

 dry mixture, plaster, flour, air-slaked lime, road dust, or 

 sifted wood ashes may be used. The strength of the mix- 

 ture required depends upon the plants and insects to which 

 it is to be applied. The strongest dry mixture now recom- 

 mended is 1 part of poison to 50 of the diluent ; but if the 

 mixing is very thoroughly done, 1 part to 100, or even 200, 

 is sufficient. 



Paris green is practically insoluble in water. When mixed 

 with water, the mixture must be kept in a constant state 

 of agitation, else the poison will settle, and the liquid from 

 the bottom of the cask will be so strong as to do serious 

 damage, while that from the top will be useless. For 

 potatoes, apple trees, and most species of shade trees, 1 

 pound of poison to 200 or 250 gallons of water is a good 

 mixture. For the stone fruits, 1 pound to 300, or even 

 350, gallons of water is a strong enough mixture. Peach 

 trees are very apt to be injured by arsenites ; and for them 

 the mixture should be no stronger than 1 pound to 300 

 gallons. In all cases, the liquid should be applied with 

 force, in a very fine spray. At some seasons of the year, 

 foliage is more liable to injury than at others. The addi- 

 tion of a little lime (twice the bulk of lime as of Paris 

 green) to the mixture, will prevent any caustic injury 

 upon the foliage. 



Spraying with Paris green or London purple does not 

 endanger stock pastured in the orchard. 



COMBINATIONS OF ARSENITES AND FUNGICIDES. The arse- 

 nites may be used in connection with some fungicides, and 

 both insects and plant diseases in this manner may be 



