RESULTS OF RECENT RESEARCHES IX COSAIICAL. 



EVOLUTION. 



(Plate XXXI.) 



By T. J. J. SEE. 

 {Read April 23, 1910.) 



Early in 1908 the writer was able to conclude the researches 

 on earthquakes, mountain formation, and kindred phenomena con- 

 nected with the physics of the earth, which this society did him the- 

 honor to publish in four memoirs,^ and it then became possible 

 to resume the study of the problems of cosmogony, which have- 

 been before him uninterruptedly since 1884. For a long time these 

 problems have defied the powers of the mathematician and natural 

 philosopher, yet for the last thirty years enough progress seemed" 

 always to be in sight to stimulate the hope and energy of investi- 

 gators; and many papers have appeared on the subject, especially 

 from Professor Sir G. H. Darwin, while lesser contributions have 

 been made by Lord Kelvin, Newcomb and Poincare, and others. 



The problem of the heat of the sun, due to condensation under 

 gravitation, had been successfully attacked by Helmholtz as early 

 as 1854, and subsequently much improved by the researches of 

 Lane, Lord Kelvin, Ritter and the writer ;- but the discoveries in 

 molecular physics made during the past decade have shown that the- 

 conclusions based on the theory of gravitation alone have to be modi- 

 fied to take account of the energy of molecular transformation 

 made familiar in radio-activity. By this hitherto unsuspected' 

 reservoir of natural forces the maintainance of the activity of the- 

 sun and stars is greatly prolonged. Accordingly, instead of reckon- 

 ing the life of the solar system in twenties of millions of years, as- 

 estimated by Helmholtz, it is now known that the actual duratiorL 



^ Cf. Proceedings, 1906-1908. 

 ^Ci. A. N., 4053. 



