John Harrison (1693- 1776) was a self-educated English carpenter and clockmaker. He invented the marine chronometer, a long-sought after device for solving the problem of establishing the East-West position or longitude of a ship at sea, thus revolutionising and extending the possibility of safe long-distance sea travel in the Age of Sail. The problem was considered so important, that the British Parliament offered financial rewards of up to £20,000 (£2.75 million) under the 1714 Longitude Act.