FISHERIES, GAME AND FORESTS. 4II 



RAINFALL DATA IN THE UNITED STATES. 



The chief sources of information as to rainfall in the United States are (1) the 

 Annual Report of the United States Weather Bureau; (2) the monthly and annual 

 publications of the various State Weather Bureaus; and (3) a large amount of manu- 

 script records collected by the Smithsonian Institution previous to the establishment 

 of the United States Weather Bureau in 1871, and now in possession of the Chief of 

 the Weather Bureau, and to be had by investigators on correspondence with his office. 

 In addition to the stations of the United States Weather Bureau located at many of 

 the important cities of the country, all of the States and Territories maintain Weather 

 Bureaus and publish the results either in monthly or annual bulletins. The State 

 records are also tabulated in the Annual Report of the United States Weather Bureau. 

 The Annual Report of the Chief of the Weather Bureau has, however, only been 

 published in its present complete form since the year 1891, and it has the disad- 

 vantage to the student who desires up-to-date data, of being about two years behind 

 in publication. If, therefore, one desires the recent data, they may be obtained from 

 the Bulletins of the State and Territorial Bureaus, or by correspondence with the 

 Chief of the United States Weather Bureau. 



TEMPERATURE. 



The foregoing statements as to sources of information about precipitation may be 

 also taken as applying to temperature, hygrometry, etc., except that, generally 

 speaking, the State and Territorial weather services have not gone extensively into 

 hygrometric observations, the most of this work being confined to the stations of 

 the United States Weather Bureau. 



MEAN ANNUAL AND MONTHLY TEMPERATURES. 



A study of the table showing variation in meteorological conditions in different 

 parts of the United States on page 409, leads to the tentative conclusion, that evapora- 

 tion from the surface of the ground varies broadly. Thus, at Abilene, Texas, the 

 mean temperature for the period considered in the table is 63. 8°, while at El Paso, 

 Texas, 450 miles west, the mean temperature is shown to be 63. 4 . The mean dew 

 point at Abilene is 47. 3 , at 8 a. m., and 45.3° at 8 p. m. ; while at El Paso it is 30.8 

 at 8 a. m., and 24. 7 at 8 p. m. At Abilene the relative humidities, as per table, are 

 76.3 and 48.0 per cent. ; while at El Paso they are 49.3 and 23.8 per cent. Vapor 

 pressures at Abilene are 0.374 an d 0.340; and at El Paso, 0.206 and 0.166; the mean 

 rainfall at Abilene, 23.79 inches, and 7.1 1 inches at El Paso. The average hourly 

 velocity of the wind at Abilene is 1 1.0 miles, and at El Paso, 9.7 miles. The country 



