ON THE TEMPERATURE OF THE SUN AND ON 

 THE RELATIVE AGES OF THE STARS AND 

 NEBULAE.* 



T. J. J. See. 

 Part First. 



ON THE GRAVITATIONAL THEORY OF THE SUN'S HEAT. 



1. The Tlieory of Helmholtz for the Condensation of a 

 Sphere of Uniform Density, 



On the occasion of the Kant Commemoration at Konigs- 

 berg, Feb. 7, 1854, Helmholtz delivered a popular address on 

 the Interaction of Natural Forces, which contained the first 

 application of the mechanical theory of heat to the radiation 

 of the sun. In such a public discourse obviously nothing but 

 the results of the calculations could be announced, as the 

 mathematical methods involved are much too abstruse for 

 a general audience ; and hence in the Populdre Vortrdge 

 there are no indications of the processes by which the com- 

 putations were made. This justly celebrated address was 

 deemed worthy of translation and republication in the Philo- 

 sophical Magazine for 1856, p. 516 ; and fortunately in this 

 English edition the great physicist was induced to give the 

 rigorous formulae used in deriving the numerical results. 



The problem is : To find the heat developed by the condensa- 

 tion of a homogeneous sphere under the influence of its own 

 gravitation. 



The potential of a homogeneous sphere upon a unit mass at 

 its surface is 



r=3 7r^-^ (1) 



• Presented in abstract to The Academy of Science of St. Louis, March 

 SO, 1899. 



