BIOGRAPHICAL MEMOIR OF JOHN WILLIAM DRAPER. 



Mit. President and Gentlemen of the A.cadeht: 



The growth of science during the last half century is nowhere 

 better illustrated than in the changes which have taken place in 

 our views with regard to the doctrine of energy. Fifty years ago 

 the imponderables held full sway and heat light and electricity 

 were considered forms of matter quite as much a.s oxygen and sul- 

 phur and iron. True here and there an advanced thinker offered 

 his protests against this conception and even made experiments to 

 prove its fallacy ; but it was not until 1844 that Melloni established 

 the essential identity of radiant light and heat, and not until 1860 

 that Foucault made his experimentum cruris with regard to light. 

 No one in America, it is believed, had a larger share in contrib- 

 uting to this entire revolution of scientific opinion than the eminent 

 man who is the subject of this notice. For more than forty years 

 he labored earnestly, persistently, successfully in the field of radi- 

 ant energy. Viewed from the standpoint of to-day much of his 

 work may be criticised, of course ; but, as he himself has said, to 

 an observer " imbued with the true spirit of philosophy even the 

 shortcomings which are detectable in it are not without a charm. 

 From the better horizon he has gained he watches his author, who, 

 like a pioneer, is doubtfully finding his way, here traveling on a 

 track that leads to nothing, then retracing his footsteps, and again, 

 undeterred, making attempts until success crowns his exertions. 

 To explore the path to truth implies many wanderings, many in- 

 quiries, many mistakes." ** ' - v 



John William Drapes was born in the parish of St. Helens, 

 near Liverpool, England, on the 5th of May, 1811. His father, 

 the Rev. John C. Draper, was a clergyman of the Wesleyan de- 

 nomination and, like others in the same calling, was in quite 

 moderate circumstances. He was always greatly interested in 

 scientific subjects, however, especially in chemistry and astronomy, 

 and owned a Gregorian reflecting telescope, with which he made 



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