Obituary. 167 



Natural Philosophy and Astronomy at Dartmouth, to which 

 position was attached the directorship of the Shattuck Observa- 

 tory. From here he was called in 1877 to become Professor of 

 Astronomy at Princeton, where he had connected with his 

 dwelling a good working observatory equipped with a nine-inch 

 equatorial, four-inch transit, pair of fine clocks with chrono- 

 graphs, etc. ; he was also director of the Halsted Observatory, 

 where in 1882 the 23-inch equatorial was installed. Here he 

 remained till 1905, when from failing health he resigned his 

 active duties and was made Professor Emeritus, returning to 

 spend the closing years of his life at his old home in Hanover. 



As might be expected from his training and his parentage, he 

 early showed a decided aptitude for astronomical observation, 

 and gave himself to that science, to which his life was devoted 

 and in which his well-deserved fame was won. He devised a 

 form of automatic spectroscope which has been in very general 

 use, and during his life made many new and important observa- 

 tions on the solar spectrum and prominences. He also verified 

 experimentally the fact that the Fraunhofer lines are slightly 

 shifted in one direction or the other, according as the source of 

 light is moving toward or from the earth, and by this method 

 was able to calculate the velocity of the sun's rotation. 



He took part in several astronomical expeditions of impor- 

 tance, observing nearly all the solar eclipses that have occurred 

 during his active life. On August 7, 1869, while at Dartmouth, 

 he had charge of the spectroscopic observations of the party to 

 observe the eclipse at Burlington, la., and at that time first saw 

 the "1474" line which characterizes the coronal spectrum (see 

 this Journal (2), xlviii, p. 288). On December 22, 1870, as a 

 member of the U. S. Coast Survey party under Professor Win- 

 lock, which observed the solar eclipse at Jerez, Spain, he for the 

 first time observed the reversal of the Fraunhofer lines of the 

 solar spectrum (this Journal (3), i, 156), an observation for which 

 in 1891 he received the Janssen medal from the French Academy 

 of Sciences. In the summer of 1872 he made spectroscopic 

 observations at Sherman, Wy., in connection with the U. S. Coast 

 Survey party, taking advantage of the high altitude (8300 feet), 

 and published lists of the lines reversed in the chromosphere 

 (this Journal (3), iv, 358)). In 1874 he was with the Watson 

 expedition to observe the transit of Venus at Pekin, China, 

 whose results were valuable, in spite of clouds. On July 29, 

 1878, the year after he went to Princeton, he had charge of the 

 Princeton expedition to observe the eclipse at Denver, Col., 

 (ibid., xv, 279). In 1882 he made observations of the transit 

 of Venus at Princeton, using the 23-inch refractor then recently 

 installed in the Halsted Observatory (ibid., xxv, 321), and in 

 1887 took a party to Russia to observe the eclipse of that year 

 at Rzev, 150 miles from Moscow, but was baffled by stormy 

 weather. Finally, May 28, 1900, he led a Princeton party to 

 observe the eclipse at Wadesboro, N. C, which was perhaps his 

 last active scientific work. 



