2 THE POPULAR SCIENCE MONTHLY. 



tory of modern physics — as in the case of the correlation of forces 

 and the undulatory theory of light — furnishes us with many in- 

 stances of wise thoughts floating like downy seeds in the atmos- 

 phere until the moment has come for them to take root. And so 

 it has been with the greatest achievement of modern thinking — 

 the doctrine of evolution. Students and investigators in all de- 

 partments, alike in the physical and in the historical sciences, 

 were fairly driven by the nature of the phenomena before them 

 into some hypothesis, more or less vague, of gradual and orderly 

 change or development. The world was ready and waiting for 

 Herbert Spencer's mighty work when it came, and it was for that 

 reason that it was so quickly triumphant over the old order of 

 thought. The victory has been so thorough, swift, and decisive 

 that it will take another generation to narrate the story of it so 

 as to do it full justice. Meanwhile, people's minds are apt to be 

 somewhat dazed with the rapidity and wholesale character of the 

 change ; and nothing is more common than to see them adopting 

 Mr. Spencer's ideas without recognizing them as his or knowing 

 whence they got them. As fast as Mr. Spencer could set forth 

 his generalizations they were taken hold of here and there by 

 special workers, each in his own department, and utilized therein. 

 His general system was at once seized, assimilated, and set forth 

 with new illustrations by serious thinkers who were already 

 groping in the regions of abstruse thought which the master's 

 vision pierced so clearly. And thus the doctrine of evolution has 

 come to be inseparably interfused with the whole mass of think- 

 ing in our day and generation. I do not mean to imply that peo- 

 ple commonly entertain very clear ideas about it, for clear ideas 

 are not altogether common. I suspect that a good many people 

 would hesitate if asked to state exactly what Newton's law of 

 gravitation is. 



Among the men in America whose minds, between thirty and 

 forty years ago, were feeling their way toward some such unified 

 conception of nature as Mr. Spencer was about to set forth in all 

 its dazzling glory — among the men who were thus prepared to 

 grasp the doctrine of evolution at once and expound it with fresh 

 illustrations — the first in the field was the man to whose memory 

 we have met here this evening to pay a brief word of tribute. It 

 is but a little while since that noble face was here with us and the 

 tones of that kindly voice were fraught with good cheer for us. 

 To most of you, I presume, the man Edward Livingston Youmans 

 is still a familiar presence. There must be many here this even- 

 ing who listened to the tidings of his death two years ago with a 

 sense of personal bereavement. No one who knew him is likely 

 ever to forget him. But for those who remember distinctly 

 the man it may not be superfluous to recount the principal in- 



