106 DEPARTMENTAL REPORTS. 



never been a systematic study of the chemistry of our forest products, 

 and this work j)romises much of interest and benefit in this direction. 



DAIRY CHEMISTRY. 



In collaboration with the Bureau of Animal Industry, the study of 

 dairy products will be continued. Many problems of great importance 

 await investigation, and work will be done in this line in so far as the 

 routine analyses of dairy products will permit. 



REVISION OF BULLETIN NO. 13. 



The early editions of the parts of Bulletin No. 13, on food adultera- 

 tion, are out of print. Work has already been commenced toward the 

 revision of these parts, for which such an unusual demand has been 

 made. A large amount of material for the rewriting of Part I, on 

 dairy products, has already accumulated. Work has alreadj^ been 

 commenced for the rewriting of the part devoted to tea, coffee, and 

 chocolate. Other parts of the bulletin will be revised and brought 

 up to date as soon as possible. 



INSECTICIDES. 



The study of insecticides, in collaboration with the Division of Ento- 

 mology, will be continued for the purpose of making a complete stud}' 

 of the chemical composition of all the insecticides sold in the United 

 States. This work will be devoted to the study of the composition of 

 new forms of insecticides as the}^ are brought upon the market. 



COLLABORATION W^ITH THE ASSOCIATION OF OFFICIAL 

 AGRICULTURAL CHEMISTS. 



This very important part of our work will be continued during the 

 year in all branches of investigation. The Secretary of Agriculture 

 has made the referees of the association special correspondents of the 

 Department, whereby they are privileged to use the frank of the 

 Department in correspondence relating to their work and in transmit- 

 ting samples for comparative study. There is probably no branch of 

 the work of the Division, now Bureau, of Cliemistry which has been 

 of such direct i^ractical benefit to the farming interests as the work 

 of this association. The existence of the association has been made 

 possible only through the patronage of the Department, which lias 

 made its work a part of the studies of the Division, and enabled the 

 results of its proceedings to be placed in a suitable form in the hands 

 of agricultural analysts tlirougliout the countiy. This work has been 

 fully appreciated, not only in this country, but also in Europe, and 

 the official methods adopted by the association are now accepted 

 throughout the world as standard methods of analysis. 



INVESTIGATION OF ROAD MATERIALS. 



The laboratory for the investigation of road materials will be more 

 fully e(juipped during the year, and, in collaboration with the Ofiice 

 of Public Road IiKjuiries, an extensive investigation will be made of 

 the physical and chemical i)roi)erties of the materials used for road 

 building. 



