THE CHEMICAL COMPOSITION OF INSECTICIDES AND 



FUNGICIDES. 



INTRODUCTION. 



Since the data on the chemical composition of insecticides and fungi- 

 cides is extremely meager and no systematic work has been done, to the 

 knowledge of the writer, in this direction by either State experiment 

 stations, private individuals, or the National Government, it was consid- 

 ered that it would be interesting as well as instructive to make a chemical 

 study of this class of compounds. It is true that several States have laws 

 relating to the composition and sale of Paris Green, notably, Texas, 

 California, Louisiana, and New York, and the last of these States pub- 

 lishes (Mich year the composition of insecticides other than Paris Green, 

 but such work as is done, excluding Paris Green, is, up to the present 

 date, very meager. Even in those States having laws governing the 

 composition of Paris Green, California is the only one. so far as the 

 writer is informed, which requires that the free arsenious oxid shall 

 bo below a certain fixed percentage. 



In pursuance of the study of the subject the chief of the Bureau of 

 Chemistry in the spring of 1900 requested the chief of the Division 

 of Entomology to collect samples of as many insecticides and fungi- 

 cides as possible throughout the United States. This branch of the 

 work was placed in the hands of Mr. R. S. Clifton, of the Division of 

 Entomology. The following circular letter was sent to all State experi- 

 ment stations and to several of the special agents of the Department 

 in different localities: 



U. S. DEPARTMENT OF AGRICULTURE, 



DIVISION OF ENTOMOLOGY, 

 }Yaxhimjt<ni, I). C, March 28, 1900. 



DEAR SIR: The Division of Chemistry of this Department is about to undertake, 

 in collaboration with this Division, an extended investigation of the insecticides 

 which are being sold on the open market in all parts of the country. With your 

 experience you can readily understand that if the samples to be analyzed were pur- 

 chased direct by this Department from the ifianufacturers we would have no guaranty 

 that they would not be doctored, and it seems necessary therefore to avoid giving 

 the information that they are purchased for chemical analysis. 1 have thought that 

 the best way we can secure them is to ask tor your assistance, together with that of 

 other members of the American Association of Economic Entomologists. Canyon, 



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