194 EXPERIMENT STATION. [Jan. 



l>iit unstable, hvdrolizing readily under favorable conditions. It 

 has a low power of suspension though its fineness permits of 

 reasonable distril)ution. It is a poor indicator without lime 

 of the leaf surface covered, but 2:)ossesses fair adhesive quali- 

 ties. 



B. Calcium Arsenite. 

 Historical. 



Early attempts to use arsenous oxide as an insecticide by 

 IJiley ^ in 1869 and Saunders and Reed - in 1871 were unsatis- 

 factory. John Smith ^ in 1808 appears to have been more 

 successful, applying it in water, but the practice proved too 

 hazardous to warrant its continuance, although freshly prepared 

 mixtures have been applied in numerous instances without 

 injury. The relatively high cost of Paris green and London 

 purple, and the necessity of adding lime to neutralize the free 

 arsenic, led to the production of lime arsenite. So far as known 

 this has always been a farm prej^aration and not a commercial 

 product. 



Kilgore ^ recommended adding 1 pound of white arsenic to 

 2 pounds of lime in 2 to 5 gallons of water and boiling thirty 

 minutes. Taft ^ advised adding 2 pounds of freshly slaked 

 lime to 1 pound of arsenic in 2 gallons of water and boiling- 

 forty minutes. Kedzie ^ suggested dissolving the arsenic in a 

 solution of sal soda and otiered the formula which bears his 

 name. Boil 2 pounds of arsenic with 8 pounds of sal soda in 

 2 gallons of water until dissolved. Slake 2 pounds of lime, 

 add to 40 gallons of water and stir in 1 pint of the arsenic 

 solution. Stewart ^ evidently noted the undue amount of sal 

 soda in the Kedzie formula and reported better results, using 

 equal parts, 2 pounds of arsenic and 2 pounds of sal soda. E. 

 L. Smith ^ recommended 2 pints of Kedzie mixture to 6 to 10 

 pounds of lime in 50 gallons of water, and claimed that the 

 additional lime increased safety and adhesiveness. 



' Potato Pests, p. 60 (1876). 

 ' Can. Ent., 3, pp. 45^7 (1871). 



' Western Poinologi.st, 2, p. 125 (1871). Cited by Lodeman. 

 < N. Car. Exp. Sta., Bui. No. 77b, pp. 7-8 (1891). 



' Mich. Bd. Agr. Rept., 35, p. 119 (1897). In Ropt. 37, p. 466 (1899), the amount of lime was 

 increased 8 pounds on application. 

 « Mich. Farmer, 31. p. 132 (1897). 

 ' Penn. Exp. Sta., Bui. No. 99, p. 11 (1910). 

 • Cal. Exp. Sta., Bui. No. 126, p. 24 (1899). 



