James Clerk Maxwell, Scottish physicist, c 1870s.

SCOTLAND - JUNE 10: Engraving by C H Jeens of James Clerk Maxwell (1831-1879. Maxwell was one of the world�s greatest theoretical physicists. Born in Edinburgh, Scotland he studied mathematics at Trinity College, Cambridge. After graduating in 1854, he became a professor first at Aberdeen (1856) and then at King's College, London (1860). He was also the first Cavendish Professor of Physics at Cambridge University (1871). Maxwell�s most important work was on the theory of electromagnetic radiation, and in 1873 he published �A Treatise on Electricity and Magnetism�. He also formulated the kinetic theory of gases. (Photo by SSPL/Getty Images)