7(\ THE UNITED STATES GEOLOGICAL SURVEY. [bull.227. 
investigation. He also made special reference to the work of gaging 
streams, and in concluding suggested the clause which was afterwards 
embodied in the first part of the act. In this he recommended that 
the sum of $250,000 be appropriated to start the work. This amount 
was reduced by Congress to $100,000. 
In expending the $100,000 appropriated by Congress on October 2, 
1888, the law was interpreted as not authorizing the construction of 
works of irrigation, but only as directing a comprehensive investiga- 
tion of conditions, and the money was expended in such way as to 
obtain the desired information in the shortest time. 
The work was found to divide naturally into two parts — the topo- 
graphic features and the engineering features. 
The topographic work consisted of surve}^s delineating the topo- 
graphic features of the country, the areas of all drainage basins, the 
courses of streams, the situations of lakes, springs, and other bodies of 
water, the positions of possible reservoir sites, the locations of dams 
and canal lines, and the altitude, position, and general character of all 
irrigable lands. These surveys were undertaken by the topographic 
branch of the Geological Surve}^, and immediately after the passage 
of the act operations were begun in Montana, Nevada, Colorado, 
and New Mexico. The methods in use by the Geological Survey were 
found to be well suited to this work, and in many localities there was 
necessary only a continuation of the work already in progress. 
The hydraulic work consisted of measuring the flow of rivers, rain- 
fall, evaporation, and matter carried in suspension by water. It also 
included the study of general meteorology, ascertaining the duty of 
water, and determining the mode and cost of constructing dams and 
reservoirs. 
At the instruction camp established, as has been said, early in the 
fall of 1888 on the Rio Grande, near Embudo, N. Mex., there were 14 
student hydrographers, whose work consisted in practicing stream 
measurements by the various methods, measuring the rise and fall of 
the stream from day to day, the daily evaporation, and the amount of 
water carried in suspension. Observations were also made with 
meteorologic instruments. 
At that time the four principal methods of gaging streams were by 
weirs, floats, formula, and meter. These methods were compared, 
both scientifically and practically, and at the close of the winter of 
1888-89 sufficiently well-defined methods had been developed to enable 
the men to be assigned to practical field duty. 
At the end of the first year methods for carrying on the various 
branches of the work had been developed, an aggregate of about 12,000 
square miles had been topographically surveyed, and gaging stations 
had been established on the more important streams in the territory 
under investigation. This was an excellent showing, for the work 
