iv OBITUARY NOTICES OF MEMBERS DECEASED. 



of physics and of the calculus of probabilities in the University of 

 Paris and in 1896 became professor of mathematical astronomy at 

 the same university. In 1904 he was also made professor of general 

 astronomy at the ficole Polytechnique. Since 1902 he occupied the 

 chair of electricity at the Ecole professionnelle superieure des Postes 

 et des Telegraphes. He died on the 17th of July, 1912. 



The importance of his scientific contributions was recognized 

 from the very beginning of his career. He received practically all 

 the distinctions which are open to a mathematician. Among the 

 most notable were : Election to the Academy of Science of France 

 (Section of Geometry) in 1887, election to the French Academy in 

 1908, and the Bolyai Prize for excellence in all fields of mathematics 

 in 1905. He was elected a member of the American Philosophical 

 Society in 1899. 



Poincare was particularly distinguished among his contemporaries 

 by the wide range of his creative power. He left behind enduring 

 works not only in the several branches of pure mathematics but in 

 astronomy, physics and philosophy. He has often been described 

 as the last of the universals. Indeed in this respect as well as in 

 the brilliance of his individual works, he is like those earlier heroes 

 of science whom Klein compared to the chain of lofty mountains. 



It goes without saying that one could not expect to give an ade- 

 quate account of Poincare's complete work in a short address like 

 this one. I shall try, however, to mention certain main divisions of 

 his work, taking them up in an order which is roughly chronological. 

 Naturally, the periods to which I shall refer all overlap but I shall 

 trv to arrange them according to the dates of the central papers in 

 each subject. 



Poincare's doctoral dissertation, which was his first published 

 work of importance, appeared in 1879. Its title was "On the Prop- 

 erties of Functions Defined by Partial Dififerential Equations " and 

 it supplies the existence theorem for solutions in the neighborhood 

 of singular points of a very general type. This memoir initiated a 

 long series of brilliant contributions to the theory of dififerential 

 equations, especially to that of linear dififerential equations. ]\Iost 

 of these papers appeared in the period before 1886. 



