L00MIS, Elias, physicist, born in Willington, Connecticut, 7 August, 1811. He was fitted for college by his father, and graduated at Yale in 1830, where in 1833-'6 he held the office of tutor. In November, 1834, for two weeks, from 4 to 6 A. M., with Alexander C. Twining, of West Point, he made observations for determining the altitude of shooting-stars. These are believed to have been the first concerted observations of this kind made in the United States. For fourteen months, in 1834-'5, he made hourly observations from 5 or 6 A. M. till 10 P. M. of the declination of the magnetic needle. He was the first person in this country to discover Halley's comet on its return to perihelion in 1835, and he computed the elements of its orbit from his own observations. In 1836-'7 he spent a year in Paris attending the lectures of Arago, Biot, Dulong, Poisson, Pouillet, and others. On his return he became professor of mathematics and natural philosophy in Western Reserve college, Ohio, where he remained until 1844, making diligent use of the philosophical and meteorological instruments that he had purchased in Europe. Professor Loomis observed during these years 260 moon culminations for longitude, 69 culminations of Polaris for latitude, 16 occultations of stars, and made a series of observations upon five comets, sufficiently extended to determine their orbits. He also observed the dip of the magnetic needle at over 70 stations, spread over 13 states, extending from the Atlantic to the Mississippi river. In 1844 he became professor of natural philosophy in the University of the city of New York, which chair he continued to fill until 1860. During this period he prepared a series of text-books embracing the entire range of mathematical subjects that are taught in high-schools and colleges, and they were subsequently extended to embrace natural philosophy, astronomy, and meteorology. This series attained an aggregate circulation of more than 500,000 copies ; his treatise on astronomy has been used as a textbook in England; that on analytical geometry and calculus translated into Chinese ; and his "Meteorology" into Arabic. A part of his time between 1846 and 1849 was employed in telegraphic comparisons for longitude with Sears C. Walker. The difference in longitude between New York and Washington was determined in 1847, that between New York and Cambridge, Massachusetts, in 1848, and the difference between Philadelphia and the observatory in Hudson, Ohio, in 1849. In the two former comparisons Professor Loomis had charge of the observations in New York, and in the latter comparison he had charge of those in Hudson. The first observations by which the velocity of the electric fluid on telegraph-wires was determined were made on 23 January, 1849, between Washington, Philadelphia, New York, and Cambridge, under the direction of Sears C. Walker, a clock in Philadelphia being employed to break the electric cir cult. In these comparisons Professor Loomis had charge of the observations in New York. In 1860 he became professor of natural philosophy and astronomy in Yale, and has since devoted a large part of his time to original researches, the most important of which are a series of articles published in the "American Journal of Science," under the title of "Contributions to Meteorology." He is now engaged in revising these papers, and arranging the different topics in systematic order, at the same time subjecting each principle to more rigid investigation by comparison with the numerous observations which have recently been published in the United States or abroad. These revised contributions, when completed, will present a very full discussion of the principles of dynamic meteorology. The titles of his scientific papers exceed 100 in number, and they have appeared both in this country and abroad in journals and in transactions of societies of which he is a member. In 1854 he received the degree of LL. D. from the University of the city of New York. Professor Loomis is a member of scientific societies in the United States and in Europe, and in 1873 was elected to the National academy of sciences. Besides "On Certain Storms in Europe and America" (Washington, 1860), forming part of one of the Smithsonian contributions, he has published "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 Loomis " (1870).