BUREAU OF CHEMISTRY. 151 



(3) A study of methods of analysis in cooperation with the Associa- 

 tion of Official Agricultural Chemists. 



(4) Preparation of reports and replies to inquiries relating to sugar 

 and other carbohydrates. 



INSECTICIDES AND AGRICULTURAL WATER LABORATORY. 



Arrangements have been made with the Division of Entomologj^ to 

 continue the collaborative work on the composition of insecticides and 

 fungicides as they appear on the market. 



Work will be continued, in collaboration with the same Division, 

 on the amount of soluble arsenious oxid which may be present in 

 Paris green and other arsenical insecticides without injury to the 

 foliage resulting from their use. Such work will also be taken up in 

 collaboration with the agricultural experiment stations, since climatic 

 conditions have a marked effect on the action of soluble arsenious 

 oxid on foliage. 



Work in collaboration with the Office of Experiment Stations (irri- 

 gation investigations) will be continued upon a study of the irrigation 

 value of the waters of our Western streams, and especially of the 

 waters in the rice belt of Texas and Louisiana. Samples will be 

 collected, according to special instructions, and analyzed in this 

 laboratory. 



The work begun on a study of the arsenic content of wall papers, 

 fabrics, etc. , will be extended and pushed vigorously, and a thorough 

 investigation of these articles on the American market will be made. 



Analyses of miscellaneous samples of insecticides, fungicides, and 

 irrigation water will be made for farmers upon application for such 

 work. 



An investigation of the mineral and drinking waters now sold upon 

 the American market will be made. This study will be of great scien- 

 tific and practical importance, since it is believed that many waters 

 are advertised to contain ingredients possessing marked medicinal 

 qualities which either do not contain such ingredients at all or at 

 most only in traces. The drinking waters will also be examined as 

 to their effect on the health of the consumer. 



A study \\dll be made of as many samples of pyrethrum as can be 

 obtained to determine if lead or barium chromate have been added 

 to give them a bright j^ellow color. This laboratory has found that 

 these two substances are often used in insect ijowders, a practice 

 which is extremely reprehensible, since it is known that both lead 

 and chromium are poisonous to human beings when inhaled. 



It is hoped that during the present year an inv^estigation of the 

 quality of the water used in dairies and creameries may be begun. 

 Practical suggestions can then be made as to the purification of such 

 water supi^lies, it being a well-known fact that much disease is caused 

 by washing cans in impure water and that the keeping quality of the 

 butter is much influenced by the character of the water supply. 



SOIL LABORATORY. 



The work during the current year will be a continuation of the 

 cooperative work with the stations, as outlined in the first part of 

 this report. This laboratory will undertake the analytical work in 

 connection with these studies, leaving the stations free for research 

 work. 



