YOUNG Charles Augustus, astronomer, born in Hanover, New Hampshire, 15 December, 1834. He was graduated at Dartmouth in 1853, and then taught classics at Phillips Andover academy for three years, during one year of which he studied at the theological seminary. In 1856 he was called to fill the chair of mathematics, natural philosophy, and astronomy at Western reserve college, Ohio. During the civil war he was captain of a company lathe 85th Ohio volunteers for three months in 1862. He was chosen professor of natural philosophy and astronomy at Dartmouth in 1865, which post had been held by his father, Ira Young, in 1838-'58, and remained there until 1877, when he accepted the chair of astronomy at Princeton. Professor Young was a member of the astronomical party" that was sent to observe the total solar eclipse of 7 August, 1869, at Burlington, Iowa., and was given charge of the spectroscopic observations of the party. On this occasion he discovered the green line of the coronal spectrum, and identified it with the line 1,474 of the solar spectrum. He was also a member of the expedition under Professor Joseph Winlock to observe the eclipse of 1870, at Jerez, Spain, and then discovered that the so-called "reversing layer" of the solar atmosphere produces a bright-line spectrum correlative to the ordinary dark-line spectrum of sunlight. In August, 1872, he was stationed at Sherman, Wyoming, to make solar spectroscopic observations, he went to Pekin as assistant astronomer under Professor James C. Watson to observe the transit of Venus on 8 December, 1874, and in 1878 he had charge of the astronomical expedition that was organized by Princeton to observe the eclipse of 29 July of that year. He devised a form of automatic spectroscope, which has been very generally adopted, and has made a great number of new observations on solar prominences. He has also verified experimentally what is known as Doppler's principle as applied to light, showing that the lines of the spectrum are slightly shifted to one direction or the other according as the source of light is moving toward the earth or away from it. By this means he has been enabled to measure the velocity of the sun's rotation. Professor Young has given popular lectures at the Peabody institute in Baltimore and the Lowell institute in Boston, and courses at Williams college, and elsewhere. The degree of Ph. D. was given him by the University of Pennsylvania in 1870, and that of LL. D. by Wesleyan university in 1876. He was elected an associate fellow of the American academy of arts and sciences in 1871, and in 1872 a foreign associate of the Royal astronomical society of Great Britain. In 1872 he was chosen to the National academy of sciences, and in 1876 served as vice-president of the American association for the advancement of science, of which organization he was president in 1883. Besides large contributions to astronomical journals, scientific addresses, and magazine articles, he has published "The Sun," in the "International Scientific Series" (New York, 1882), and "A Text-Book of General Astronomy" (Boston, 1888).