JOHN WILLIAM DRAPER. 



architectural subjects, but wholly unsuited to landscape scenery or 

 to portraits. The inventor himself' had made attempts at applying 

 it to the taking of likenesses, but had given it up in despair. S< .< .n 

 after the publication of Daguerre's invention in America a series 

 of experiments was conducted in our laboratory with a view of de- 

 termining whether the difficulties could be removed." The results 

 were successful, and the taking of portraits from life by daguerreo- 

 type became before long an everyday operation. 



The great value of Dr. Draper's contributions to science has been 

 cordially recognized by the highest authorities. Melloni,the creator, 

 as it were, of the science of radiant heat, warmly congratulated him 

 on his memoir on this subject, presented an abstract of it to the 

 Royal Academy of Sciences at Naples, and in his own subsequent 

 memoir warmly commends the ingenuity and ability of the Amer- 

 ican scientist. Herschel was equally cordial in praise of his photo- 

 chemical researches. Berzelius, a few days before his death, sent 

 to Dr. Draper his portrait with a kind message conveying his ap- 

 preciation of what he had done for science. Kirchhoff, in 1862, 

 thus speaks of his heat experiments : " Draper has derived from ex- 

 periment the conclusion that all solid bodies begin to glow at the 

 same temperature, but he has observed in his experiments that cer- 

 tain bodies, as chalk, marble, and fluor-spar, shine at a lower tem- 

 perature than they should according to this law; he calls this light 

 phosphorescent and observes that it is distinguished from the glow 

 by its color. But whatever name may be given to the light it eon 

 tradicts the law, and a body which shows it cannot satisfy the as- 

 sumption which is made in proving the law ; it cannot remain un- 

 changed, the temperature remaining the same ; the phosphoresence 

 is not the simple influence of heat, it is not exclusively conditioned 

 on temperature, but it is caused by changes in the body ; if these 

 changes, be they chemical or of any other kind, cease, then the 

 phosphoresence must also vanish." Bunsen and Roscoehave recog- 

 nized Dr. Draper most fully as the pioneer in the investigation of 

 the action of light upon chlorine, a subject worked out successfully 

 by them. 



Dr. Draper was elected a member of many of the learned societies 

 of Europe, among them the Aecadeinia dei Lincei, at Rome, and 

 the Physical Society of London. In 1843 he was elected a member 

 of the American Philosophical Society at Philadelphia, and in 

 1860 he received the degree of LL. D. from the college of New 



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