Page:The Biographical Dictionary of America, vol. 03.djvu/327

 DRAPER

DRAPER

DRAPER, John William, scientist, was born at St. Helens, near Liverpool, England, May 5, 1811 ; son of the Rev. John Christopher and Sarah (Ripley) Draper. He attended a Wesleyan acad- emy at Woodhouse Grove, and in 1829 studied chemistry at the University of London. He was married in 1831 to Antonia Coetana de Paiva Pereira, daugh- ter of Dr. Gardner of Rio Janeiro, attend- ing physician of Dom Pedro I., Emperor of Brazil. Her mother was the daughter of Sefior de Paiva Pereira of Portugal, whose great-grand- father was captain of Vasco de Gama's ship M'heu he circumnav- igated Africa in 1497. Before the Revolu- tionary war some of John W. Draper's an- cestors on his mother's side had emigrated to America, and had founded a small Wesleyan community in Virginia. Subsequently others of the family had joined them ; and after the death of his father in 1829 John "William was urged by these relatives to go to America. Accordingly in 1832 he settled in Christianville, Mecklenburg county, Va. His sister Catherine gave lessons in music and painting, and thus enabled him to take the course of lectures in the medical school of the University of Pennsylvania, from which he was graduated in 1836. In the same year he became professor of chemistry and physics at Hampdeu- Sidney college, Va. ' He resigned his chair in 1838 to accept that of chemistry and physiology in the University of the city of New York, which he held until his death. In 1841 he was instrumen- tal in founding the University medical college, in which he was professor of chemistry until 1881, and chief executive officer, 1850-73. Before the termination of his medical course his experiments resulted in the discovery that gases pass more or less rapidly, in some cases instantaneously, through barriers such as bubbles or membranes "having no proper pores." This showed that what had been knowTi as endosmosis was a process not confined to liquids, and elucidated the method of the oxygenation of the blood. He made this discovery the subject of his graduation thesis, which was published by the faculty, and at once attracted the attention of the scientific world. He continued his experiments, and contributed papers on their results to the principal scientific journals of America. He explained by practical demonstration the circulation of the sap in j^lants

and of the blood in animals, as being results of osmotic action ; and in 1844 published a volume entitled " A Treatise on the Forces that Produce the Organization of Plants. ' ' It combated the ex- istence of the so-called "vital force " of physiolo- gists. In 1839 he made the first daguerreotype of the human face, his sister being the sitter, and in 1840 made a daguerreotype of the moon one inch in diameter. He associated himself with Prof. S. F. B. Morse, then a portrait painter in the university building, in carrying on the experi- ments which resulted in the invention of the electric telegraph, aiding that inventor in the construction of batteries and other apparatus. He daguerreotyped the prismatic spectrum in 1842 and the diffraction spectrum in 1843. In the latter year he also invented a chlor-hydrogen photometer and a ferric-oxalate photometer. In- vestigating the phenomena of the solar spectiiim he doubled the number of discovered lines. In 1847 he studied the phenomena of incandescence and ascertained that it is only the spectrum of a gaseous body that shows lines at all. He thus anticipated Kirchoff"s conclusions by thirteen years. In 1848 he made a spectrum analysis of various flames, proving that of whatever origin they yield all the colors of the spectrum. The finest telescopes failed to resolve many of the nebulee into distinct points of light. Astronomers had been puzzled as to the explanation of this. Dr. Draper's discoveries in spectrum analysis showed that if the spectrum of an irresolvable nebula consist of bright lines, it is a gaseous body ; if on the other hand the spectrum is con- tinuous, that body is an incandescent solid ; thus affording means of inferring the constitution of the remote heavenly bodies. He was the first to make microscopic photographs, 1858. In 1872 he experimented on the distribution of heat and chemical force in the solar spectrum. For his " Researches in Radiant Energy " he was awarded by the American academy of arts and sciences in 1875 the Rumford gold medal. He was a member of many scientific societies, includ- ing the National academy of sciences ; the Ameri- can philosophical society ; the American academy of arts and sciences ; the Accademia dei Lincei of Rome ; and the Physical society of London. The College of New Jersey conferred upon him the degree of LL.D. in 1860. His bibliography, com- prising books, scientific memoirs, lectures and addresses, includes ninety-two titles. These may be found in Professor Barker's memoir of Pro- fessor Draper, read before the National academy of sciences. The books are as follows : Elements of Chemistry, by Robert Kane ; American edition edited by J. W. Draper (1842) ; A Treatise on the Forces tohich Produce the Organization of Plants (1844) ; Text-bool- on Chemisti-y (1846) ; Text-book