 On his return to England he married his second wife, Sarah Horne, who was a sister of John Horne Tooke.In 1755 he read a public course of lectures in the concert-room in Panton Street, and later gave private courses to members of the royal family, including the future King George III.In 1768, he was appointed Superintendent of the King's Observatory (or King's Astronomer) in Richmond, which King George III had commissioned from Sir William Chambers.