BUREAU OF CHEMISTRY, 



453 



Agriculture, and other laboratories of the Bureau of Chemistry, as 

 follows : 



Treasury Department 2 



War Department 9 



Department of Commerce and Labor 2 



Interior Department 5 



Isthmian Canal Commission 13 



Department of Agriculture: 



Bureau of Plant Industry 386 



Bureau of Entomology 347 



Bureau of Forestry- 15 



Irrigation and Drainage Investigations 4 



Bureau of Animal Industry 1 



Unclassified samples examined for various other departments and bureaus and 



other laboratories of the Bureau of Chemistry 78 



Total 862 



EXAMINATION OP WATERS. 



The water laboratory, under the food and drugs act, examines 

 samples of mineral and table waters wliich enter into interstate com- 

 merce, and also those which are imported into this country. It also 

 analyzes public water supplies for the purpose of detecting pollution 

 and suggesting remedies therefor; examines water for irrigation and 

 technical purposes, and mineral springs of the United States from 

 source, and studies improved methods of water analysis. 



During the year 257 samples were examined, classified as follows: 



Interstate samples 161 Miscellaneous water samples 53 



Foreign samples 39 Miscellaneous samples 4 



Of the 161 interstate samples, 39 were found to be adulterated or 

 misbrandcd, and 6 seizures were made. Of the 39 samples of foreign 

 waters considered, 11 were found to be mlsbranded and their exclu- 

 sion from the United States was recommended. The miscellaneous 

 samples examined for this department and other branches of the 

 Government service were as follows: 



War Department 5 



Interior Department 5 



Commerce and Labor 2 



4 



Drainage investigations 



Plant Industry 3 



Forest Service 12 



Unlisted 26 



The investigation of mineral springs at source has been continued 

 and the data obtained collated. The first section of this investiga- 

 tion, which includes the springs from New Enlgand, has been issued 

 as Bulletin 139, Bureau of Chemistry. Several other lines of original 

 research previously begun have been continued. The spectroscopic 

 method for lithium, which has been perfected in this laboratory, has 

 been subjected during the past year to further trial and investigation 

 and has definitely proved its reliability and worth. The investiga- 

 tion of the radioactivity of certain mineral waters has been con- 

 tinued and the technique of the method employed has been greatly 

 improved. Some time has been devoted also to the perfecting of 

 methods for the analysis of water for sanitary, technical, and indus- 

 trial purposes, in cooperation with other official chemists. The 

 character of certain chemicals used in water purification is being 

 investigated, and the quantity of such substances remaining in the 

 water determined. 



