TABLES 159-162. SOLAR ENERGY. 179 



TABLE 159. Solar Energy and Its Absorption by the Earth's Atmosphere. 



The following values depend upon the formula e m = too., where e m is the observed value of the 

 solar energy after transmission through a mass of air, m; m = unity when the sun is in the zenith, 

 and approximately=sec. zenith distance for other positions of the sun. e = the energy which 

 would have been observed had there been no absorbing atmosphere ; a is the amount transmitted 

 when the sun is in the zenith or when m = i. 



* These may be too high because of the usual increased humidity towards noon at Mount Wilson. 



TABLE 160. - Solar Constant 



Solar constant (amount of energy falling at normal incidence on one square centimetre per min- 

 ute on body at earth's mean distance) = 1.92 small calories. Mount Wilson and Mount Whitney 

 observations. 



Computed effective temperature of the sun : Goldhammer's method (Ann. der Phys. (4) 25, 

 905, 1908), 6200 Absolute ; from form of black body curves, 6000 to 7000 j from A. max. = 2930, 

 6370 ; from Total Radiation, J = 76.8X1 o~ 12 , 5830. 



TABLE 161. -Distribution of Brightness (Radiation) over the Solar Disk. 



(These observations extend over only a small portion of a sun-spot cycle.) 



TABLE 162. Relative Distribution in Normal Spectrum of Son and Sky-light at Mount Wilson. 



Zenith distance about 50. 



Derived from vol. II and unpublished data of the Astrophysical Observatory of the Smithsonian Institution! Abbot 

 and Fowle, Astrophysical Journal, 29, 1909, and Schwartzchild and Villiger, same Journal, 93, 1906. 



SMITHSONIAN TABLES. 



