158 FARM FRIENDS AND FARM FOES 



be thoroughly done. When a good powder gun is used, it 

 is not so necessary to dilute the poison. 



During recent years, arsenate of lead has become one of 

 the most generally used of arsenical insecticides. It is 

 made by combining arsenate of soda with acetate of lead 

 in water, and is commonly offered for sale in the form of 

 a thick paste. This insecticide has a great advantage over 

 Paris green in that it may be applied even to tender foliage 



A SIMPLE SPRAYING OUTFIT 



without injury to the plant. It also remains upon the leaves 

 longer than any other arsenical insecticides. Under special 

 conditions it may be advisable to prepare the arsenate of lead 

 at home, but usually this is scarcely worth while. A dry, 

 powdery form of this poison has lately been put upon the 

 market, and is likely to be very useful for applying with 

 various sorts of powder bellows. 



Trouble has been observed in some Western states in 

 injury to the health of trees from the use of arsenate of lead. 

 The poison appears to penetrate the soil and be absorbed 

 through the roots. On this account arsenic sulphide has 

 been substituted in an experimental way, and promises to be- 

 come an important insecticide. It is less soluble than other 

 forms of arsenic, and also less expensive. 



