Elias Loomis, an American mathematician, born in Tolland co., Conn., in August, 1811. He graduated at Yale college in 1830, where he was tutor from 1833 to 1836. He was the first person in America to obtain a view of Halley's comet, at its return in August, 1835, and his observations on that body, with a computation of its orbit, were published in the "American Journal of Science." He also made a series of hourly observations on the declination of the magnetic needle, continued through more than a year. In 1836 he visited Europe, spending a year in Paris, where he attended the lectures of Poisson, Biot, Dulong, and Pouillet. Returning home in 1837, he became professor of natural philosophy in the Western Reserve college, Ohio. Here he made many astronomical and magnetic observations, and kept a full meteorological journal. The larger portion of his researches appear in 10 memoirs contributed to the " Transactions of the American Philosophical Society," vols, vii.-x. In 1844 he became professor of natural philosophy in the New York university, which office he retained till 1860. A portion of the time between 1845 and 1849 he was employed, under the direction of the superintendent of the coast survey, in determining the difference of longitude between New York and other cities, by means of the electric telegraph.

In the course of these experiments the velocity of the electric current through telegraph wires was first determined. In 1860 he succeeded Prof. Olmsted as professor of natural philosophy in Yale college. His contributions to science relate for the most part to astronomy, magnetism, and meteorology. Besides the memoirs above referred to, some 30 or more papers of his have appeared in the "American Journal of Science;" one, on storms, in the "Smithsonian Contributions to Knowledge;" two astronomical papers in Gould's "Astronomical Journal;" and one or more yearly in the "Proceedings of the American Association for the Advancement of Science." He has also published the following works: "Plane and Spherical Trigonometry" (New York, 1848); "Progress of Astronomy" (1850 and 1856); "Analytical Geometry and Calculus," and "Elements of Algebra" (1851); "Elements of Geometry and Conic Sections" (1851 and 1871); "Tables of Logarithms" (1855); " Natural Philosophy " (1858); " Practical Astronomy " (1855 and 1865); "Elements of Arithmetic" (1863); "Treatise on Meteorology" (1868); "Elements of Astronomy" (1869); and " The Descendants of Joseph Loo-mis" (1870).