21 



II. GREEN ARSENITE. 



Under this name the Adler Color and Chemical Works have 

 placed upon the market an arsenical which may be used in place 

 of ordinary Paris green. As stated in the Fifteenth Annual 

 Report of this Station, pagts 536-539. samples were sent to the 

 Station in 1896 for experiment. During 1897 two other samples 

 were sent for the same purpose. In addition to the experiments 

 the poison has been extensively used in place of Paris green in 

 the station orchard during the past two seasons with excellent 

 results. 



NATURE AND COMPOSITION OF GREEN ARSENITE. 



In general appearance green arsenite resembles ordinary Paris 

 green. It differs chemically from this poison in being a simple 

 arsenite instead of an aceto-arsenite of copper, and physically in 

 being an impalpable powder while Paris green is crystalline. 



Green arsenite is said to be similar to if not identical with 

 Scheele's green, but according to samples sent by the manufac- 

 turers to the Station the percentage of arsenious oxide may vary 

 from 41.04 to 62 per cent, while Scheele's green contains, theoret- 

 ically 52.94 per cent. 



WHEN FIRST USED USED AS AN INSECTICIDE. 



Mr. C. L,. Marlatt of the United States Department of Agricul- 

 ture, Division of Entomology, was probably the first to use 

 green arsenite in place of Paris green. Mr. Marlatt' states that 

 copper arsenite ( green arsenite ) was especially made for him in 

 1894 by a prominent manufacturer of Paris green and that it is in 

 reality Paris green, without the addition of acetic acid which is 

 added to produce a more or less coarsely crystalline product. 



In a publication of the Department of Agriculture, Mr. Mar- 

 latt' gives the results of experiments with this insecticide. He 



8 Insect Ivife, 7: 408-411. 



9U. S. Dept. Agr. Div. Ent. Bui. 2, n. ser. 



