THE 



POPULAR SCIENCE 



MONTHLY. 



PEBEUARY, 1902. 



STELLAR EVOLUTION IN THE LIGHT OF RECENT 



RESEARCH.* 



By Peofessoe GEORGE E. HALE, 



DIEECTOE OF THE YEEKES OBSEEVATOBY, 

 UNIVEESITY OF CHICAGO. 



"A /TANY attempts have been made to sum up the work of 

 -^'-L the nineteenth century, and to define its principal lines of 

 progress. In estimates of the relative importance of the books pub- 

 lished during this period there has been some divergence of view, but 

 regarding one of them no element of doubt seems to have entered the 

 minds of the critics. By unanimous consent Darwin's 'Origin of 

 Species' is accorded a commanding position among the works which 

 have influenced the intellectual life of the century. It would be diflS- 

 cult to overestimate the effect which the doctrine of evolution has 

 wrought. The principle of orderly and harmonious development 

 which it embodies has found application, not only in explaining the 

 v/ide diversity of organic species, but in unifying the events of history, 

 in elucidating the origin of language, and in throwing light on diffi- 

 cult questions in every department of human knowledge. The idea of 

 evolution may indeed be traced back through the writings of many cen- 

 turies. The early philosophers, though not possessed of the immense 

 collection of recorded phenomena by which modern men of science may 

 test their theories, were constantly occupied with great problems de- 

 manding the widest generalization. In attempting to account for the 

 earth and its inhabitants they made the first steps in the direction 

 which Darwin subsequently pursued. 



• Revised from an address delivered on June 5, 1901, before the Minnesota 

 Chapter of the Honorary Scientific Society of Sigma XI, University of Minne- 

 sota. 



