1903.] 



PUBLIC DOCUMENT — No. 33. 



23 



As in the past, we have collected and analyzed samples 

 of Paris green and other insecticides found in our general 

 markets. The analysis of these materials will be found in 

 oui' March bulletin, No. 81, for 1902. 



We have been eno-ag-ed in work for the Association 

 of Official Agricultural Chemists, to assist in the selection 

 of the best methods of analysis of insecticides, etc., and 

 have taken up co-operation work for the association on 

 new methods of potash determination. The results of this 

 work do not appear in our publications, the work being of 

 technical nature, and of value only to the Association of 

 Official Agricultural Chemists in the establishment of new 

 methods of analysis. 



We are constantly occupied with investigations of new 

 methods for the determination of the available plant food in 

 soils, and new and improved methods for the ash analysis of 

 plants, and have been to considerable expense in procuring 

 the equipment for the latter work, being obliged to import 

 most of the apparatus from Germany. The equipment con- 



