REPOET OF THE SECRETARY. 41 



EVAPORATION STUDIES. 



Studies of evaporation were continued at the Salton Sea, and a 

 summary of the observations is being prepared. The problem of 

 the rate of evaporation has been a difficult one to solve. The rates 

 differ greatly for different points on or near the water and under 

 different conditions of wind movement and elevation. The records 

 of the Geological Survey show that the sea has been falhng at the 

 rate of about 55 inches annually for the past three years. The 

 coefficients of evaporation deduced by the Weather Bureau from its 

 experiments indicate an annual evaporation from the surface of 

 about 70 inches. As the annual water inflow is thought to be about 

 15 inches, it will be seen that the results arrived at experimentally 

 by the Bureau are in close accord with the observed general facts at 

 that point, and, furthermore, that the coefficients established will 

 probably be equally applicable to conditions of evaporation any- 

 where. 



NEW APPARATUS. 



Observations were made during the winter of 1909-10 with various 

 forms of snow gauges suited for installation in the mountain districts 

 of the West, whereby an accurate catch could be obtained and also 

 be presei'ved for measurement at extended intervals. Further 

 experiments will doubtless soon develop the best form of apparatus. 

 New methods of measuring the intensity of solar radiation in abso- 

 lute units of heat, by the use of the electrical resistance thermometer, 

 were perfected during the year, and detailed drawings of a seismo- 

 graph adapted to record very destructive earthquakes was supplied 

 to the University of CaUfornia by the Bureau. 



It appears proper at tliis point to renew a former recommendation 

 that Congress be requested to authorize and provide for seismo- 

 logical work, and to place it under the control of the Weather Bureau, 

 which is already prepared through its widely distributed corps of 

 regular and cooperative observers to collect and study earthquake 

 observations. That the Bureau is prepared to conduct tliis work in 

 an effective manner and at far less expense than any other depart- 

 ment of the Government has already been recognized by the Seismo- 

 losical Committee of the American Association for the Advancement 

 of Science, which, at its meeting in Wasliington in 1907, voted that 

 the Federal Government be requested to support seismological work, 

 and that the appropriations therefor be made tlirough the Weather 

 Bureau. 



MARINE WORK. 



The Marine Division continued to prepare and publish pilot and 

 meteorological charts for the oceans, and will shortly begin the issue 

 of a meteorological chart for the Great Lakes. A duplicate of the 



