Karl Friedrich Gauss, a German mathematician, born in Brunswick, April 30, 1777, died in Gottingen, Feb. 23, 1855. He early displayed such remarkable capacity for mathematical calculation, that the duke of Brunswick took charge of his education. At the age of 18 he solved a problem which had occupied geometers from the time of Euclid, that of the division of the circle into 17 equal parts. In 1801 he published his Disquisitiones Arithmetical, treating of indeterminate analysis or transcendental arithmetic, and containing, besides many new and curious theorems, a demonstration of the famous theorem of Fermat concerning triangular numbers. This gave him at once a distinguished place among scientific men. He was one of the first to calculate by a new method the orbit of the newly discovered planet Ceres, and afterward that of Pallas, for which he received from the French institute in 1810 the medal founded by Lalande. In 1807 he was appointed professor of mathematics and director of the new observatory at Gottingen, a position which he retained till his death. Having undertaken for the government of Hanover in 1821 the measurement of an arc of the meridian for trigonometrical purposes, he introduced important improvements in geodesy.

To render the angles visible at as great a distance as possible, he invented the heliotrope, which accomplishes the object by reflecting the rays of the sun, and devised a method for the correction of the errors which occur in an extensive system of triangulation. After the arrival of Weber in Gottingen in 1831 Gauss employed his leisure principally in the investigation of magnetism. He invented the magnetometer for ascertaining the variations of the magnetic needle, and became member of the Magnetischer Verein, through the instrumentality of which valuable observations on terrestrial magnetism were made and the results published (6 vols., Gottingen, 1837-43). His works mark an era in the history of science. As a mathematician he was pronounced by Laplace the greatest in Europe. Among the more important of his works are: Theoria Motus Cor-porum Coelestium (Hamburg, 1809; translated into English by C. H. Davis, Boston, 1857, and into German by Haase, Hanover, 1865); In-tensitas Vis Magneticoe Terrestris (Gottingen, 1833); Atlas des Erdmagnetismus (3 vols., Leipsic, 1840); Dioptrische Untersuchungen (Gottingen, 1841); and Untersuchungen uber Gegenstande der hohern Geodesie (1845-'7).