(MORS, HEINRICH 'WILHELM MATISIAS, a celebrated Gernatti physician and astrono mer, was born at Arbergen. a small village of Bremen, Oct. 11, 1758. He studied medi cine at Gottingen from till 1780, and subsequently commenced to practice at Bremen, where, both as a physician and as a man, he was esteemed by his fellow citizens. In 1811 he was a successful competitor for the prize proposed by Napoleon for the best "Memoir on the Croup." Others wrote little on medical subjects, for, froM 1779. all the leisure time which he could abstract from professional occupations was devoted to the enthusiastic study of astronomy. The first thing which brought him into notice was his calculation of the orbit of the comet of 1779, which was performed by hitt - while watching by the bedside of a sick patient,. and was found to be very accurate: a Comets were the chief objects of his investigation. and he seems to have been seized with an irresistible predilection for these vagabonds of lie solar system, which his two impor tant discoveries of the planets Pallas (1802)and Vesta (1807) could not diminish. In 1781 he had the honor of first re-discovering the planet Uranus. which liad previously beet supposed, even by Herschel himself, to be a comet, and which had been sought for in vain. He also discovered five comets. in 1798, 1802, 1804, 1815, and 1821, all of Which with the excep on of that of 1S15 (hence called OlberA's cornet). had been some days pre viously observed at Paris. His observations, calculations, and notices of various comets; which are of inestimable value to astronomers, were published hi the. Annuai•e of Bode (1782-1829), in the Annuai•e qf Encice (1832). and in three Collections by the baron di Zach. Most of these calculations were made after a new method, discovered by himself, for determining the orbit of a comet from three observations; a method which, for facil ity and accuracy, he considered as greatly preferable to those then in use. A detail of it
appeared in a journal published at Weimar (17971, and a new edition by Eneke in 1847. Olbers was one of that small band of astronomers which included also Schroter, Gansi Piazzi. Bode, Harding, etc., who in the first ten years of the 19th c. devoted their ener gies to the observation of those planets which were coming to light between Mars and Jupiter. As above stated, two of them. the second and fourth in order of discovery, were detected by Olbers himself; and the general equality of the elements of the four planetoids led him to propound the well-known theory, that these. and the other planet oids (q.v.) since discovered, are _ telt. fragments of. some „large planet which formerly revolved round the sun at a equal to the :mean of the planetoids from the same luminary. It was this theory which led him, after the discovery of Pallas, to seek for more fragments of the.supposed planet, it search resulting in the discovery of Vesta. Olbers also made some important researches on the probable lunar origin of meteoric stones, and invented a method for calculating the velocity of falling stars. Olbers died at Bremen, Mar. 2, 1840; and in 1850 his fellow-citizens erected a marble statue in honor of him. Olbers, as a writer, possessed great powers of thought, com bined with equal clearness and elegance of expression. The dissertations with which he enriched the various branches of astronomy are scattered through various collections, journals, and other periodicals.