1912. 



PUBLIC DOCUMENT — No. 31. 



189 



work was performed on too small a scale to warrant positive 

 statements to that effect. 



Attention has already been called, on pages 180 and 181 to 

 two samples of Paris green supplied by different manufacturers 

 for the investigation, of which the second was employed in 

 actual spraying tests. The sample of instantaneous green was 

 made according to the method described, with the exception that 

 crystallized copper acetate was substituted for verdigris. The 

 slow process sample was selected from a factory run of commer- 

 cial green manufactured substantially as has been stated. 



Paris Green from Chemical Manufacturers. 



Both greens contained an excess of cupric oxide and acetic 

 acid, and may have been hydrolyzed somewhat by washing with 



' Determined by the entomological department of this station. 



