Maxwell, James Clerk (klärk) [key], 1831–79, great Scottish physicist. After a brilliant career at Edinburgh and Cambridge, where he won early recognition with mathematical papers, he was professor at Marischal College, Aberdeen (1856–60), and at King's College, London (1860–65). In 1871 he was appointed first professor of experimental physics at Cambridge, where he directed the organization of the Cavendish Laboratory. He is known especially for his work in electricity and magnetism, summarized in A Treatise on Electricity and Magnetism (1873). Basing his own study and research on that of Faraday, he developed the theory of the electromagnetic field on a mathematical basis and made possible a much greater understanding of the phenomena in this field. He was led to the conclusion that electric and magnetic energy travel in transverse waves that propagate at a speed equal to that of light; light is thus only one type of electromagnetic radiation. Maxwell's electromagnetic theory occupies a position in classical physics comparable to Newton's work on mechanics. One of his early papers, "On the Stability of Motion of Saturn's Rings" (1859), was especially important and foreshadowed his later investigations of heat and the kinetic theory of gases. He is also known for his studies of color (which led to his invention of the color disk named for him), and color blindness. In addition to his papers in these fields, he wrote a classic elementary text in dynamics, Matter and Motion (1876).