326 CONNECTICUT EXPERIMENT STATION REPORT, I907-I908. 



received quotations as follows: In loo lb. kegs, from 9.5 to 13 

 cents per lb.; in 5 to 20 lb. buckets, from il to 16 cents per 

 lb.; and in i lb: cans from 11.5 to 17 cents per lb. The 

 advantage of purchasing in quantity is apparent. 



ITS ADVANTAGES. 



Lead arsenate is very effective against leaf-eating insects. Its 

 chief advantages over Paris green are its greater adhesive power 

 and its harmlessness to the foliage. A single treatment of lead 

 arsenate will adhere to the foliage for a period during which two 

 or three sprayings with Paris green would be necessary to secure 

 the same effect. The insolubility of its arsenic makes possible 

 the use of large quantities ■(vithout danger even in inexperienced 

 hands. Prom the standpoint of effectiveness lead arsenate, 

 although containing but from one-third to one- fourth as much 

 actual arsenic as Paris green, is nearly as economical as the latter 

 poison when sold at the same price. Purchased at the wholesale 

 quotations noted elsewhere, and considering the duration and 

 safety of its action, it is actually somewhat cheaper than Paris 

 green. Furthermore, its greater power of suspension makes it 

 more easily used and insures a more uniform distribution of the 

 poison over the plant. 



PARIS GREEN. 



There is no law in this State regulating the sale of Paris green, 

 but where a state inspection is in effect the requirements are 

 generally very similar to those in the New Jersey law,* section 

 3 of which reads : 



" Paris green, or any product analogous to it, when sofd, offered or 

 exposed tor sale as such, in this State, shall comply with the following 

 retjiiirbments : 



"First. It shall contain arsenic, in combination with copper, equivalent 

 to not less than fifty per centum arsenious oxide. 



" Second. It shall not contain arsenic in water-soluble forms equivalent 

 to more than three and one-half per centum of arsenious oxide." 



Many analyses of Paris green have been made by the various 

 Experiment Stations, showing the green to be of variable com- 

 position. These variations are chiefly due to different methods 

 of manufacture or carelessness in carrying out the same. In 

 many cases a large amount of the arsenic exists as free arsenious 



* New Jersey Expt. Station, Bull. 195. 



