John Harrison

John Harrison (March 24, 1693 - March 24, 1776) was an English clockmaker who revolutionised and extended the possibility of safe long distance sea travel in the Age of Sail by inventing a long-sought and critically-needed key piece in the problem of accurately establishing the East-West position, or longitude, of a ship at sea. The problem was so intractable that the British Parliament offered a huge fortune for the day (£20,000, roughly £6 million in 2007 terms) for a solution.

Harrison finally designed and built the world's first successful marine chronometers, a highly accurate maritime time-keeping instrument which for the first time allowed a navigator to accurately assess his ship's position in longitude. On long voyages, cumulative errors in dead reckoning frequently led to shipwrecks and lost lives. Avoiding maritime tragedies became imperative in Harrison's lifetime because this was an era when trade and navigation were on an explosive increase around the globe due to the maturing of other technologies, and also due to geo-political circumstances.