Stephen Alexander, LL. D., an American astronomer, born in Schenectady, N. Y., Sept. 1, 1800. He was educated at Union college and at Princeton theological seminary, was appointed tutor in the college of New Jersey in 1833, adjunct professor of mathematics in the same institution in 1834, professor of astronomy in 1840, of mathematics in 1845, and of mechanics and astronomy in 1854. In 1860 he went to the coast of Labrador at the head of an expedition to observe the solar eclipse of July 18. He has written many scientific papers, which have excited considerable interest, including one on the "Physical Phenomena attendant upon Solar Eclipses," read before the American philosophical society at their centenary meeting in 1843; one on the "Fundamental Principles of Mathematics," read before the American association for the advancement of science in 1848; one on the "Origin of the Forms and the Present Condition of some of the Clusters of Stars, and several of the Nebulae," read at the meeting of the American association at Albany in 1850; and several communications to the same association relative to the " Form and Equatorial Diameter of the Asteroid Planets," and also on the "Harmonies in the arrangement of the Solar System, which seem to be confirmatory of the Nebular Hypothesis of Laplace."