592 ANNUAL REPORTS OF THE DEPARTMENT OF AGRICULTURE. 



Waticr Laiioratory. 



Durinfj the year the water laboratory examined 4G7 samples, 

 classified as follows: 



IntiTstjite saini)le.s 202 



Foreigu samples 43 



Miscellaneous samples 222 



Of the 202 interstate samples, 18 were found to be adulterated 

 and misbrandod and 2 seizures were made. Of the 43 foreign sam- 

 ples, 8 were found to be niisbi-anded and their exclusion from the 

 United States recommended. The miscellaneous samples examined 

 for this department or other branches of the Government service 

 were received from : 



R[oiiihors of Con.cress 6 



Deimrtment of Coiunierce and Labor 5 



War Departmeut 4 



Office of Experiment Stations 10 



Forest Service 7 



Bureau of Plant Industry 7 



Unlisted 5 



Investigations of mineral springs at source have been continued 

 and the collection of the data of the springs of New York, New 

 Jersey, and Pennsylvania has been completed. 



An investigation of considerable magnitude was undertaken in 

 collaboration with the bacteriological laboratory for the purpose of 

 determining the character and source of pollution of the Potomac 

 River and the effect of such pollution upon oysters and other shell- 

 fish. This work involved the exan.iination of 133 samples of water 

 and two trips doAvn the river in the effort to determine the probable 

 sources of contamination. 



Investigation of the radioactivity of certain mineral waters has 

 been continued, with special study of some of the Virginia mineral 

 springs. A limited amount of time has been devoted in collaboration 

 with other chemists of the Association of Official Agricultural Chem- 

 ists to a study of methods for the analysis of water for sanitary, tech- 

 nical, and industrial purposes, report of which work was published 

 in the proceedings for 1911. The investigation of the character of 

 certain chemicals used in water purification and of their effect from 

 hygienic and sanitary standpoints has been carried on. 



The study of methods for the determination of lithium which has 

 been in progress for the past three or four years has been brought to 

 final completion, and the data obtained have been collated and pub- 

 lished as Bulletin 153 of this bureau. 



Insecticides and Fungicides. 



The composition and methods of manufacture of insecticides and 

 fungicides, as well as the effect they have on foliage, are studied with 

 the idea of increasing their efficiency and suggesting methods of 

 avoiding injury to vegetation, and also of suggesting to the farmer or 

 fruit grower how such products may be prepared. Investigations to 

 improve and discover new insecticides are always under way, and 

 methods of analyzing the various materials of this nature are being 

 studied and any improvements made therein are adopted. 



