George Sinclair

George Sinclair (Sinclar) (ca.1630–1696) was a Scottish mathematician, engineer and demonologist. The first Professor of Mathematics at the University of Glasgow, he is known for Satan's Invisible World Discovered, (c. 1685), a work on witchcraft. He wrote in all three areas of his interests, including an account of the "Glenluce Devil", a poltergeist case from , in a 1672 book mainly on hydrostatics but also a pioneering study of geological structures through his experience in coal mines. Life He was probably from the East Lothian area. He became a professor of the University of Glasgow, 18 April 1654, initially in a philosophy chair, then in a chair founded for mathematics. In 1655 he made descents in a diving bell off the Isle of Mull, to look at the wreck of a ship from the Spanish Armada there. He was deprived of his university post in 1666, as a Presbyterian. He then worked as a mineral surveyor and engineer, and was employed in particular by Sir James Hope. He was brought in by the magistrates of Edinburgh, about 1670, to oversee piping of water from Comiston into the city. On 3 March 1691, University of Edinburgh appointed him again to the professorship of mathematics, which had been vacant.