GAUSS, KARL FRIEDRICII, one of the most illustrious mathematicians of modern times, was h. at Brunswick on April 30, 1777. In 1795, he went to the university of Gottingen, where, at this early age, he made a number of important discoveries, one of which may be mentioned, as it had occupied the attention of geometers from the time of Euclid, viz., the division of the circle into 17 equal parts. He soon afterwards returned to Brunswick, and there, in 1801, published his Disquisitiones Mathernaticce, a work treating of indeterminate analysis or transcendental arithmetic, which contains, besides other important theorems, a new demonstration of that of Fermat concerning triangular numbers. While Gauss was at work ou these speculations, he was in great measure ignorant of what had been done in the same subject by previous mathemati cians, which accounts for the presence in his work of a number of old theorems. But the discovery of the planet Ceres on the first day of the 19th c. guided the energies of Gauss into a new field of research. He was one of the first to calculate the elements of its orbit, according to methods of his own invention, and his assiduous application; and the accuracy of his results; excited general admiration. Ou the discovery of Pallas by Olbers in 1802, Gauss set himself to calculate its orbit; and his results, valuable at the time, are even now models of ingenuity and research. For these labors, he received, in 1810, from the French institute, the medal founded by Lalande. In 1807, he was appointed director of the observatory at Gottingen, an office peculiarly suited to his tastes, and about this time commenced to prepalPe for publication his celebrated work, 77aeoria Motes Corporum Calestium in Seetionibus Conicis Ambientium, which appeared in 1809. In this work, Gauss has developed a method of calculating, in the most simple,
and at the same time most exact manner, the orbits of the bodies in the solar systein. It is also to him that the credit is chiefly due of discovering the great comet of 1811, the elements of whose orbit he calculated with the most surprising accuracy.
In 1821, Gauss was charged by the Hanoverian government with the triangulation of the kingdom of Hanover, and the measurement of an arc of the meridian. In exe cuting this work, Gauss found that the appliances then in use did not allow of the vertices of the triangles being seen from a considerable distance with sufficient distinct ness, and to remedy this defect, he invented the heliotrope (q.v.). About 1831, 'Wilhelm Edward Weber arrived at Gottingen, and communicated to Gauss a part of his own enthusiasm for magnetic researches. It would take up too much space to give a full account of the many discoveries he made in this new branch of study; suffice it to say, that he has invented a " magnetometer" which measures the " magnetic intensity" with great accuracy, and that he has probably contributed more to the advancement of this branch of science than any one before him. Gauss was pronounced by La Place to be the greatest mathematician of Europe. He died at Gottingen on /O. 23, 1855. Among his most celebrated works, besides the two above mentioned, are the Disquisitio de Ji2ementis Ellipticis cx Olvositionibus Annorum 1803-9 (1810); Theoria Comirinationis Obserrationum Erroribus Jfinimis Obnoxice (Gottingen, 1823), con taining a full explanation of his peculiar metbpd above mentioned; Intensitas 2i8 1114 netiece Terrestris act Afensuram Absolutam Revocata (1832), etc.