BUEEAU OF CHEMISTRY. 479 



The most important of the 83 unclassified samples examined were 

 hops, food dyes, and macaronis analyzed to determine whether or 

 not arsenic was present. The greater part of these miscellaneous sam- 

 ples were examined at the request of other departments or other 

 bureaus of the Department of Agriculture. 



Examination of waters. — The Water Laboratory under the food 

 and drugs act examines samples of mineral and table waters which 

 enter into interstate commerce 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 

 waters for irrigation and technical purposes and mineral springs of 

 the United States from source, and studies improved methods of 

 water analysis. 



During the year 349 samples were examined, and out of the 50 

 foreign waters 18 were found to be mislabeled. Of the 241 inter- 

 state samples of bottled mineral and table waters and ice 37 were 

 found to be illegal. Thirty complete analyses of samples of water 

 from fish-hatchery stations in various sections of the country were 

 made at the request of the Bureau of Fisheries of the Department 

 of Commerce and Labor. Miscellaneous samples examined for other 

 branches of the government service were as follows: War Depart- 

 ment, 2 ; United States Senate, 1 ; Interior Department, 31 ; Bureau 

 of Plant Industry, 10; Bureau of Forestry, 8; Drainage Investiga- 

 tions, 3. 



The investigation of mineral springs at source has been continued, 

 and data previously obtained collated. 



Several other lines of original research previously begun have 

 been continued. The investigation of a method for determining very 

 small amounts of lithium has been completed, and has been of great 

 value in determining lithium in samples of mineral waters collected 

 under the food and drugs act. The investigation of the radio- 

 activity of certain mineral waters has been continued, and the data 

 obtained have been used in examining products claiming radio-active 

 products. A study of sulphur waters and of the several forms of 

 sulphur compounds existing in waters was begun. Some time has 

 also been devoted to the perfecting of methods for the analysis of 

 waters for sanitary, technical, and industrial purposes. 



Insecticides and fungicides. — The composition and method of 

 manufacture of insecticides and fungicides are studied, as well as 

 the effects that they have on foliage, with the idea of increasing the 

 efficiency of these products and suggesting methods of avoiding 

 injury to vegetation. Investigations to discover new and improved 

 insecticides are being constantly made and improved methods of 

 examining various insecticides are being studied. 



The greater number of the 214 samples examined were the products 

 of cooperative work with the Bureau of Entomology and the Bureau 

 of Plant Industry. In addition to the examination of samples sub- 

 mitted for analysis considerable time was given to the investigation 

 of problems connected with the use and application of insecticides. 

 Questions are always arising in their use which require the coopera- 

 tion of the chemist in their solution. During the past year 8 inves- 

 tigations of this character, requiring more than 300 determinations, 

 were made. One of the most important of these was in collaboration 



