4 o8 THE POPULAR SCIENCE MONTHLY. 



tial chemistry ever made.' He was the first to obtain a photograph 

 of the fixed lines in the spectra of stars, and he continued the work 

 until he had obtained impressions of the spectra of more than one 

 hundred stars. 



When the commission was created by Congress for the purpose of 

 observing the transit of Venus, in 1874, Professor Draper was in- 

 trusted with the charge of the photographic department. He spent 

 much time in the preparations, for which he declined to receive any 

 compensation. So signal was the success of his disinterested exer- 

 tions, that the commissioners had a gold medal struck in his honor at 

 the Philadelphia Mint, bearing the inscription, though in an extinct 

 tongue, "He adds luster to ancestral glory." In 1878 he went to the 

 Rocky Mountains to observe the total eclipse of the sun, and there 

 successfully photographed the spectrum of the solar corona. For the 

 last two or three years he had been much engaged in the difficult work 

 of photographing nebulas, and he startled the scientific world by the 

 announcement that he had succeeded in getting a fine photograph of 

 the great nebula in Orion and of its spectrum. 



Professor Draper was not a prolific author, like his father, and 

 only wrote one book ; but he died in the prime of life, and had he 

 lived would undoubtedly have given to the world the results of his 

 ripened investigations in enduring treatises. He, however, wrote 

 much for the scientific periodicals, describing the results of his work. 

 He contributed several papers to the " American Journal of Science 

 and Arts " and to "Nature." He published in 1864 a " Text-Book of 

 Chemistry," and a paper on the " Philosophic Use of Silvered Glass 

 Reflecting Telescopes." The paper was published in "The Philo- 

 sophical Magazine." In the same year he published a pamphlet on 

 "Silvered Glass Telescopes and Celestial Photography." "The Quar- 

 terly Journal of Science," in 1865, published his views of " Petroleum, 

 its Importance and its History," and " American Contributions to the 

 Spectrum Analysis." The Smithsonian Institution, in its " Contribu- 

 tions, vol. xiv., of 1864," published a paper on " Construction of Sil- 

 vered Glass Telescopes, Fifteen and a Half-Inch Aperture, and their Use 

 in Celestial Photography." The following papers have been published 

 in "The American Journal of Science and Arts" : "On the Diffrac- 

 tion Spectrum Photography," in 1872 ; " Astronomical Observations 

 on the Atmosphere of the Rocky Mountains," and " Spectra of Venus 

 and a Lyrce," in 1877 ; " Discovery of Oxygen in the Sun by Photog- 

 raphy, and a New Theory of the Solar Spectrum," which was fol- 

 lowed by another paper on the same subject, entitled " On the Coin- 

 cidence of the Bright Lines of the Oxygen Spectrum with Bright 

 Lines in the Solar Spectrum," in 1877 ; " Eclipse of the Sun in 

 July, 1878," in 1878 ; Photographing the Spectra of the Stars 

 and Planets," in 1879 ; " Photograph of Jupiter's Spectrum," and 

 "Photograph of the Nebula in Orion, on September 30, 1880," in 



