Gregory, James,1638–75, Scottish mathematician. He invented a reflecting telescope (1661), which he described in his Optica promota (1663). In 1668 he became professor of mathematics at the Univ. of St. Andrews and, in 1674, professor of mathematics at the Univ. of Edinburgh. He originated a photometric mode of measuring the distance of stars and wrote Geometriae pars universalis (1668) and Exercitationes geometricae (1668).
Born 1638 in Aberdeen; died 1675 in Edinburgh. Scottish mathematician and astronomer. Member of the Royal Society of London (1668).
Gregory was a professor at the University of St. Andrews (from 1669) and the University of Edinburgh (from 1674). He developed one of the first designs for a reflecting telescope. He worked out a technique for calculating the area of a sector of a circle, hyperbola, and ellipse. This was related to his attempt to prove that circular and logarithmic functions cannot be reduced to algebraic operations. He calculated areas using series. In 1668, Gregory derived the formula for approximate integration, later rediscovered by the English mathematician T. Simpson.