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CHEMISTRY OF FARM PRACTICE 



of the paste or half of that quantity of the powder, to 50 

 gallons of the spray solution. Whether used as paste or 

 powder, the lead arsenate should first be stirred or ground 

 very thoroughly in a small amount of the spray solution, 

 and gradually diluted until a very smooth paste is formed. 



Paris green is a mixture of copper acetate and copper 

 arsenite. It is somewhat more soluble than is lead arsenate 



FIG. 72. Knapsack sprayer. The handle can be removed and the 

 tank carried in the hand instead of on the back, if desired. (Far- 

 mers' Bulletin 243, U. S. Dept. Agr.) 



and, for this reason, it may injure tender foliaged plants. 

 Paris green has been largely superseded as an insecticide by 

 lead arsenate. It may be applied dry by diluting with from 

 10 to 50 parts of land plaster, flour or road dust. When used 

 in this way, there is danger of burning tender foliage. A 

 solution of 1 pound of Paris green and 3 pounds of stone 

 lime in 100 to 250 gallons of water, depending on the foliage, 

 is advised. 



