(1809-1868) Natural Philosopher, son of Sir William Forbes, of Pitsligo, was born and educated at Edinburgh. He studied law, and was called to the Bar, but devoted himself to science, in which he gained a great reputation both as a discoverer and teacher. He was Professor of Natural Philosophy at Edinburgh, 1833-1859, when he succeeded Sir D. Brewster, as Principal of the United College at St. Andrews. He was one of the founders of the British Association in 1831. His scientific investigations and discoveries embraced the subjects of heat, light, polarisation, and specially glaciers. In connection with the last of these he wrote Travels through the Alps (1843), Norway and its Glaciers (1853), Tour of Mont Blanc and Monte Rosa (1855), and Papers on the Theory of Glaciers.