2io THE POPULAR SCIENCE MONTHLY 



windings and caprices of the continuous laws that join quantities together, there 

 is not one of his works which has not the masterly touch, not one of his fifteen 

 hundred publications which does not show the lion's claw. 



At the age of twenty-seven, the Faculty of Sciences offered this young 

 conqueror its chair of physical mechanics. At thirty-three the Academy of 

 Sciences opened its door, an example soon followed by the learned academies of 

 the entire world; for there was no body of scientists in Europe or America 

 which did not feel that it honored itself in adjoining the cooperation of Henri 

 Poincare\ 



But the mathematical sciences were for this illustrious analyst only a mani- 

 fold and prodigious measuring instrument admirably adapted to the comparative 

 etudy of the phenomena of the universe. This instrument he set himself to use, 

 and what skill he displayed! At the age of thirty, he astonished the physicists 

 by his critique of the general principles of their science; that was but the 

 beginning of bold speculations which led him year by year up to the very edge 

 of the unknown, to the constitution of matter, to the paradoxical mechanics 

 that sprung up after the unexpected discovery of the mysterious radioactivity. 



Yet this was only part of his activity: geodesy, cosmogony, astronomy, 

 philosophy of science, he included them all, penetrated all, explored all. His 

 celestial mechanics would be glory enough. It was this that revealed him first 

 to a wide public. King Oscar II. of Sweden, Maecenus of science, enlightened 

 and generous, in 1887 opened an international competition in mathematics. In 

 1889, at the end of the contest, France learned with joy that the great gold 

 medal, supreme prize of this new tournament, had been awarded to one of her 

 children, a young scientist thirty-five years of age, for a marvelous study of the 

 mechanical stability of our universe; and the name of Henri Poincare' was 

 famous. 



Gentlemen, the Theban hero dying after two victories said: "I leave two 

 immortal daughters. ' ' This hero of the world of thought who has just suc- 

 cumbed, leaves in the ideal world, as real as the other world, an immortal pos- 

 terity which will guide the future researches of men. Indeed his life will remain 

 an example as harmonious in its faultless lines as the orbits of those stars whose 

 eternal past and eternal future he desired to know. 



To this eulogy of Professor Painleve certainly I could add nothing, 

 and it does not seem necessary to enumerate the many other honors of 

 Poincare's. I shall undertake only to consider briefly his conception of 

 science in its chief phases, and in the light of this conception to con- 

 sider at more length in particular his ideas of research. As an investi- 

 gator his opinions carry extraordinary weight, as he was a subtle phi- 

 losopher and a skilled psychologist. We may treat three phases of sci- 

 entific activity as distinct, pure science, industrial science and what we 

 may call euthenic science. 



In speaking of the death of Brouardel, 3 who did much for the study 



of hygiene, and had helped in preventing three invasions of cholera, 



without disturbing commerce, Poincare said before the Academie des 



Sciences : 



In this direction scientists can scarcely count on the satisfaction of dis- 

 covering general laws, exterior as it were to space and time, but there are other 



l C. B., 143 (1906), p. 996. 



