HYDRO-ECONOMICS. 89 
lina, and Georgia. The work has since constantly enlarged from year 
to year, until it now includes every State in the humid region. 
A special department of the work, and one of a distinctly economic 
character, was established in 1897, when a detailed study of the sources 
of pollution of the Potomac Basin was undertaken. Samples of water 
for bacteriologic examination were collected in sterilized bottles at the 
mouths of all important tributaries, and at such other points along 
the river as were of special interest, as at locations of sawmills, tan- 
neries, and immediately below important towns. 
At about this time in the New England States, especially in Maine, 
the study of water powers Avas commenced. In four }^ears the subject 
was fairly well covered, and the results were published in Water- 
Supply Paper No. 69. 
During 1895, 1896, and 1898 a study of the hydrography of the 
streams of New York State was undertaken by the State engineer's 
office and the United States Board of Engineers on Deep Waterways. 
During 1900 the Geological Survey assumed charge of the stations, 
and, in cooperation with the State engineer and surveyor, extended 
and continued the work. 
In 1901, at the request of the water-supply department of the cit} r 
of New York, a detailed study of the hydrography of the streams that 
might possibly furnish a water supply for the city was undertaken by 
this Survey, and has been continued to date. 
Owing to the increased demand for information on water powers, 
municipal water supplies, sanitaiy conditions of rivers, flood preven- 
tions, and other allied questions, the division of hydro-economics was 
established in January, 1902. At that time its work was confined to 
reviewing chemical and board-of -health reports and extracting there- 
from such matter as applied directly to the quality of natural waters. 
From the results of this work there was prepared a report entitled 
Normal and Polluted Waters in Northeastern United States," which 
has been issued as Water-Supply and Irrigation Paper No. 79. 
Subsequently cooperative relations with various laboratories through- 
out the country were established. The arrangements involve the study 
of important problems concerning river pollution, river purification, 
and municipal water supply. The laboratories partaking in the initial 
scheme of cooperation were: Bowdoin College, Brunswick, Me.; Mas- 
sachusetts Institute of Technology, Boston, Mass. ; Rensselaer Poly- 
technic Institute, Troy, N. Y.; Cornell University, Ithaca, N. Y.; 
University of Rochester, Rochester, N. Y.; Dickinson College, Carlisle, 
Pa.; Earlham College, Richmond, Ind. ; Central University of Ken- 
tucky, Danville, Ky.; University of St. Louis, St. Louis, Mo.; Uni- 
versity of Missouri, School of Mines, Rolla, Mo. ; University of Kansas, 
Lawrence, Kans. 
