Mathematician. Born at Rothesay on the Isle of Bute, son of a minister. Educated at the University of Glasgow. Became Professor of Mathematics at the University of Edinburgh in 1747. His specialist field was geometry, and amongst other contributions, he made an attempt to calculate the sun's distance from the earth (he over-estimated the distance by about a third). His most famous work is his General Theorems published in 1746. Between 1775 and 1785, he shared the Chair with his son, Dugald Stewart (1753 - 1828).