74 THE UNITED STATER GEOLOGICAL SURVEY. [bull. 227. 
The subject of magnetic declination has been studied by this division, 
and an extensive compilation of the measurements of declination taken 
within the United States has been made, including a complete canvass 
of the data available in the United States Land Office, Avhere hundreds 
of thousands of measurements derived from the subdivision service are 
recorded. By the aid of these data the magnetic declination in the 
Central and Western States is now as well known as it was formerly 
in the Northeastern States. The secular variation has been studied, 
and its movements during the last century within the limits of the 
United States have been ascertained. 
The subject of physiography has received attention, especially as 
illustrated by the atlas sheets of this Survey. Their use as a means 
of instruction in the schools has been forwarded by the preparation 
and publication of three folios — two of them entitled "Physiographic 
Types" and the third "Physical Geography of the Texas Region." 
The compilation of a gazetteer of the United States, to comprise all 
names found on the atlas sheets, has been commenced by the prepara- 
tion of gazetteers of the States. Thirteen such gazetteers have been 
compiled. 
The profiles of the rivers of the United States have been studied and 
a publication has been made thereon (Water-Supply Paper -1-1). 
The compilation of measurements of altitudes has been continued, 
and the results have been presented in a revised and extended edition 
of the "Dictionary of Altitudes" (Bulletin 160). 
The stud} 7 of the boundaries of the States and of the United States, 
with a history of their development, has been continued, and three 
bulletins on that subject have been issued (Bulletins 13, 171, 226). 
A compilation has been made of the origin of place names, and the 
results have been published in a bulletin, which contains such informa- 
tion regarding about 10,000 names in the United States (Bulletin 197). 
For titles of all publications prepared by this division see the 
Survey's list of publications. 
HYDROGRAPHIC BRANCH. 
The hydrographic investigations of the Geological Survey began, as 
a distinct feature of its work, in the fall of 1888 with the establish- 
ment of a camp of instruction at Embudo, N. Mex., under the charge 
of the present chief of the branch. They have been continued and 
gradually expanded, the work being strengthened as larger funds 
became available. The first specific appropriation for gaging streams 
was made in an act of Congress approved August 18, 1894, being 
$12,500. This amount has been added to from time to time, and the 
work has expanded to a point where several divisions and sections 
have been organized to cover the various needs of different parts of 
the countrv. 
