GAUSS, KARL FRIEDRICH German mathematician and physicist, was born at Brunswick on April 30, 17 7 7. He was the son of a bricklayer and owed his education to the influence of the reigning duke. He went to the Caroline college and later to Gottingen. In 1798 he returned to Bruns wick, where he tried to earn his living by teaching privately. When the new observatory at Gottingen was completed in 1807, Gauss became Director and Professor of Astronomy. lie prac tically never left the observatory until he died on Feb. 23, Gauss began his mathematical researches at an early age; this early work was incorporated in his Disquisitiones Aritlirneticae (18oi) which is a standard work on the theory of numbers. This was followed by a large number of memoirs in pure mathe matics. Because of this work he is ranked with Laplace and Lagrange among the three greatest masters of modern mathe matical analysis. Amongst other researches in this connection Gauss made extensive use of determinants and imaginaries ; he arrived at the method of least squares; observed the double peri odicity of elliptic functions ; applied vigorous tests on the con vergence of an infinite series, and worked out a solution for binomial equations. He wrote on biquadratic residues, and solved the problem of the representation of numbers by binary quadratic forms ; he also proved the law of quadratic reciprocity.
Gauss began his magnetic and electrical researches about 1830; his first memoir, Intensitas vis magneticae terrestris ad men suram absolutam revocata, was published in 1833 ; in this he pro posed a system of units based on the units of length, mass and time. He called these units absolute units and the unit of mag netic field has been named the Gauss. With Weber he constructed a magnetic observatory free from iron where they made observa tions and from which they sent telegraphic messages along a crude line which they erected. In connection with his magnetic meas urements, Gauss organized a German Magnetic Union so that magnetic observations were taken at a fixed time at various places in Europe. Gauss and Weber designed the instruments used in these measurements, notably an apparatus for measuring declina tion and the unifilar and bifilar magnetometers. The union worked from 1834 to 1842, and their results were published in memoirs Resultate aus den Beobachtungen des Magnetiscizen Vereins . In these memoirs we find the inverse square law and Gauss's theory on earth magnetism; this theory is a mathematical presentation of the distribution of magnetism over the earth's surface rather than a theory to account for the exist ence of earth magnetism. Gauss applied mathematics to electro static and electrodynamic problems; his theories were based on assumptions concerning the position and motion of imponderable electrified particles. He also carried out researches in optics and particularly on systems of lenses. These were published in Dioptrische Untersucliungen (1840). A memoir on capillary at traction contains a solution of a problem in the calculus of varia tion and another on attractions treats of the attraction of homo geneous ellipsoids. Gauss took part in geodetic surveys, and wrote two memoirs, Uber Gegenstdnde der hoheren Geodesie (1843 and 1846). He also wrote a treatise on astronomy, Tlieoria motus cor porum coelestium (1809) .