Olinthus Gregory (1774-1841), English mathematician and astronomer. Founder of both the London University and the Astronomical Society, where he was secretary. Gregory was professor of mathematics at the Royal Military Academy in Woolwich, London. He is the author of many books, and was instrumental in assisting engineers with problems relating to friction, kinematics (the motion of objects) and material strength. In 1823 he gave supporting evidence to the House of Commons Committee considering a grant application from Charles Babbage for his difference engine (calculating machine).