SPRAYS AND SPRAYING 137 



creased the yield of potatoes from 175 bushels per acre, 

 on plats where bugs were removed by hand, to 221 

 bushels per acre, and that it was better applied in 

 water than in lime water. 



Lead Compounds. Insoluble arsenate and arsen- 

 ite of lead are recommended because they contain no 

 injurious soluble arsenic, a heavy dose will do no 

 harm, they lead all other materials in remaining in 

 suspension, they adhere to the foliage, and they can 

 be easily made at home and their purity insured. The 

 articles required are sugar of lead (acetate of lead), 

 costing 7^ cents per pound, wholesale, and arsenate 

 of soda, costing 5 cents per pound, wholesale, at pres- 

 ent. They may be dissolved in cold water, but for 

 quick solution hot water is better. The formula for 

 making i pound of arsenate of lead enough for 100 

 gallons is: 



Dissolve 24 ounces of sugar of lead in i gallon of 

 cold water, and 10 ounces of arsenate of soda in 3 

 quarts of water, both in wooden vessels. 1 When dis- 

 solved, pour together into the spraying-tank. Pre- 

 pared in this way, it is superior to any ready prepared 

 sample. Of the latter there are several makes, which 

 may be used if but a small amount is required. ' ' Swift's 

 Arsenate of Lead ' ' may be purchased in a white 

 powder form or as a paste; it is easily mixed with 

 w r ater, but both forms settle more quickly in the spray- 

 tank than the freshly made. Disparene retails at 25 

 cents per pound, and is a heavy white paste which 

 finally mixes well with water, but takes some time. 



Cal. Bui. 151. (N. Y.) Geneva Bui. 243. 



