Carpenter and self-taught mechanic who pioneered the development of portable clocks.

In 1714 the British Government offered a prize of £20,000 to anyone who could accurately determine longitude at sea. In 1730 Harrison introduced his marine chronometer, or sea clock, which cracked the longitude problem. He scooped the prize in 1759 with his fourth clock (H4), but it was 1773 before he received all the money, equivalent to over £2 million today. H4 resembled a giant pocket watch, and is considered to be the forerunner of all precision watches.