84 THE UNITED STATES GEOLOGICAL SURVEY. [bull. 227. 
(Sec PL IX.) This is indicated by a buzz. The cable serves the 
double purpose of supporting the meter and of transmitting the cur- 
rent from the battery. A tail keeps the meter headed against the 
current, and leaden weights hold it at the proper depth. With the 
exception of the conical cups the various parts and appliances of this 
meter have been modified by "hydrographers of the Geological Survey. 
The data collected by this division have formed the basis of all 
reclamation investigations, and the success of the reclamation service 
is largely dependent upon the hydrographic studies of the last fifteen 
years. In the East, where the data are principally used in estimates 
for water-power developments, power plants costing in the aggregate 
millions of dollars have been built, based upon information furnished 
by the hydrographic division. 
The records of the division have been of great value in estimating 
available water supplies for large cities, and the data have proved of 
great importance in lawsuits or arbitration for settling satisfactorily 
the relative rights of various claimants on the basis of the physical 
facts. Information in regard to floods is a later but no less important 
feature of its investigations. 
For publications prepared by this division see the Survey's list of 
publications. 
DIVISION OF HYDROLOGY. 
Eastern and Western Sections. 
The division of hydrology deals with underground waters, in the 
same manner that the division of hydrography deals with surface 
waters, the aim being to obtain and publish for the benefit of the 
people information relating to the occurrence, movements, methods 
of obtaining, and uses of artesian and other underground waters, 
including those reaching the surface both in wells and in springs. 
As underground waters are intimately connected with many geo- 
logic features, more or less attention has been given to them through- 
out the existence of the Survey, but mostly in connection with the 
investigation of other problems. Two special reports, one on the 
conditions of artesian wells and another on the hot-spring deposits of 
the Yellowstone National Park, were published in the Fifth and Ninth 
annual reports, respectively; and papers on potable waters and on 
natural mineral waters appeared in the Fourteenth Annual Report. 
To carry out the provision of the act of October 2, 1888, previously 
quoted (p. 75), the hydrographic work of the Survey was organized, 
and during the first year some progress was made in the investigation 
of underground water supplies. Every year since 1888 more or less 
hydrologic work has been done, by field investigations in both the 
West and the East. These have yielded a number of reports on under- 
ground-water resources, and a large collection of data is preserved in 
the oflice for future reference and elaboration. 
