<Tr> <Td_colspan="2"> Scientific career </Td> </Tr> <Tr> <Th> Fields </Th> <Td> Horology </Td> </Tr> <P> John Harrison (3 April (O.S. 24 March) 1693--24 March 1776) was a self - educated English carpenter and clockmaker who invented a marine chronometer, a long - sought - after device for solving the problem of calculating longitude while at sea . </P> <P> His solution revolutionized navigation and greatly increased the safety of long - distance sea travel . The problem he solved was considered so important following the Scilly naval disaster of 1707 that the British Parliament offered financial rewards of up to £ 20,000 (equivalent to £ 2.89 million today) under the 1714 Longitude Act . </P>

Who solved the problem of longitude at sea