138 THE POTATO 



It has great adhesive power, and will not burn foliage. 

 The Adler lead compounds are similar. 



Arsenite of lead is made by dissolving separately 1 2 

 ounces of sodium arsenite and 4 pounds of sugar of 

 lead, then pouring them into 150 gallons of water. 

 The home-made mixture remains in suspension longer 

 than the prepared. Pink arsenoid is arsenite of lead 

 colored; it is no more dangerous to foliage than Paris 

 green, and is cheap. It will remain in suspension about 

 twice as long as Paris green. 



Green arsenoid (copper arsenite) sometimes con- 

 tains considerable soluble white arsenic, and is then 

 dangerous to foliage, especially in a dry climate or 

 time. 



White arsenoid (barium arsenite) is dangerous to 

 foliage. 



Calco green and laurel green do not contain enough 

 arsenic to render them of much value, and some sam- 

 ples cause serious injury to foliage. 1 



Paragrene is a prepared compound containing, in 

 some cases, considerable soluble ' ' white arsenic, ' ' which 

 is objectionable. 



Arsenic and lime is a cheap mixture. Boil i pound 

 of white arsenic, costing 7 cents per pound, with 2 

 pounds of lime in 2 gallons of water for forty minutes 

 and add to 150 or 200 gallons of water. It cannot be 

 safely applied alone, even with the addition of consid- 

 erable lime, but may be used in Bordeaux mixture. 

 The copper sulphate in the Bordeaux mixture seems 

 to prevent the caustic action. If the lime and arsenic 

 fail to combine, the mixture is dangerous. 



1 Vt. Report, 1899, p. 271. Cal. Bui. 151, p. 24. 



