282 Trans. Acad. Sci. of St. Louis. 



Eliminating R in the last two equations 



T= T,B-^. (28) 



There is reason to believe that the solar atmosphere extends 

 300,000 miles, or 4.828X10^" cm. above the solar surface. It 

 has been pointed out that the fineness of the Fraunhofer lines 

 in the spectrum of light originating at the photosphere, makes 

 it exceedingly improbable that a deeper atmosphere can exist. 

 The solar radius is 6.972X10^° cm. It will be assumed that 

 at the outer limit of the atmosphere, where R = R = 

 1.180X10" cm., the temperature is 1° C. At the solar sur- 

 face the temperature is at least 5500° C, and is probably 

 more. 



According to (26) and (27), by the elimination of B, the 

 temperature at the center of the sun is, 



'og ^' = E^ '"" ^- 



The numerical values aboTC given being inserted, T^ is 

 found to be 1.338X10^ degrees C. It is more than likely 

 that at the solar surface there exist condensation effects, in 

 the form of metallic clouds, fogs, and rains. The result will 

 probably be to diminish the temperature gradient somewhat, 

 for points within the sun. The law of temperature probably 

 changes at the solar surface. For such internal points it may 

 in fact be desirable or necessary to assume another logarithmic 

 curve, intersecting the one represented by (26), at the sur- 

 face of the sun, the constants of which shall be so assumed 

 that the known conditions of mass and surface temperature 

 shall be satisfied. As a preliminary to this study, it seems 

 desirable to learn the results of the assumption involved in 

 (26). 



As contraction of the solar nebula has proceeded, the dis- 

 tance R has diminished, and T, has increased. Those quanti- 

 ties are to be considered as time functions. In the beginning, 

 as equation (27) shows, the value of B must have been unity. 



