Alexander Bruce, 2nd Earl of Kincardine

Alexander Bruce, 2nd Earl of Kincardine FRS (1629–1681) was a Scottish inventor, politician, judge and freemason, responsible for developing the pendulum clock, in collaboration with Christiaan Huygens.
His grandfather, Sir George Bruce had built up a fortune in coal-mining and salt-production, building Culross Palace in Fife in 1597.
In 1659 he married Veronica, a sister of Cornelis van Aerssen van Sommelsdijck and delivered stone or marble of the townhall of Amsterdam. On 20 June 1667 Bruce is listed as a Treasurer of Scotland. In the same year he was an Extraordinary Lord of Session.
Bruce was one those making up the 1660 committee of 12 that led to formation of the Royal Society of London, and he conducted extensive correspondence with fellow freemason Sir Robert Moray, the first President of the Royal Society. These letters are the main source of biographical information on Bruce.