Hammond.] ^^^ [March 3, 



The chemical actiou of light was a favorite study with liim. In 1844 he 

 published his work on the "Forces which produced the Organization of 

 Plants," in which he showed that the yellow ray of the solar spectrum is 

 the most poAvcrful in its influence over vegetation. One of the most im- 

 portant contributions made by him to science is that in which he demon- 

 strates that all solid substances become incandescent at about the tem- 

 perature of 977° F. 



Dr. Draper did not confine his studies to the Natural Sciences strictly 

 so-called. He was ambitious of distinction as a historian. His basis was, 

 that nations are subject to the same laws as individuals and that in their 

 migrations and stages of development they have been acted upon by purely 

 physical^ causes. We are inclined to think that he carried his views in 

 this respect, too far, and that he disregarded the undoubted influence of 

 intellectual and emotional factors as creators and modifiers of history. 



Dr. Draper's contributions to Scientific Periodicals and the Transactions 

 of Medical Societies have been very numerous. One paper only was pre- 

 sented to the American Philosophical Society, and this was May 27th, 1843. 

 He was elected a member of the Society January 19th, 1844, and conse- 

 quently this memoir was submitted before he joined us : its title is, "On 

 the Decomposition of Carbonic Acid and the Alkaline Carbonates by the 

 Light of the Sun." It is published in Vol. Ill of the Proceedings. 



His published volumes are as follows : 



" A Treatise on the Forces which produce the Organization of Plants," 

 1844. 



"A Text-Book of Chemistry," 1846. 



"A Text-Book of Natural Philosophj%" 1847. 



"A Treatise of Human Physiology," 1856. 



"History of the Intellectual Development of Europe," 1862. 



"Thoughts on the Future Civil Policy of America," 1865. 



"History of the American Civil War," 1867-70. 



" History of the Conflict between Religion and Science," 1877. 



In all these works Dr. Draper showed that he had read extensively and 

 thought deeply. He had great facility for expressing himself with clearness 

 and directness and hence for impressing his views upon others. Never- 

 theless it must be confessed, that his chief claim for distinction will rest 

 upon his labors in Chemistry and Natural Philosophy. His "Treatise on 

 Human Physiology" is in many respects fiinciful and speculative, and 

 theories are promulgated as well-founded which have no support from 

 facts. His historical works are characterized by an entire absence of refer- 

 ences to the sources of his information, and therefore they lost much of 

 the value which they would otherwise possess for students. 



In 1876 he was awarded the Rumford Medal by the American Academy 

 of Arts and Sciences, for his researches on Radiant Energy. In 1881 he 

 was elected one of the twelve honorary members of the Physical Society of 

 London. 



