A village carpenter who taught himself to build clocks — and solved the problem that the finest astronomers of Europe could not.
At sea in the 1700s, no captain could reliably say how far east or west he was. Latitude could be read from the Sun; longitude needed the exact time at home, and no clock could keep it on a rolling, salt-soaked, freezing-then-sweltering ship. Fleets ran aground on coasts they believed were far away. In 1714 Parliament offered £20,000 — a fortune — to anyone who could fix longitude at sea to within half a degree.
The astronomers expected to win it from the stars. Instead it was won by John Harrison, a Yorkshire carpenter's son with no university education, who built his first clocks out of wood and then spent the rest of his life making a clock that could cross an ocean without losing its place. He did it. It took him more than forty years to be paid for it.
Eighty-three years, to the day
The lifeline
1693
Born 24 March in Foulby, Yorkshire; raised in Barrow upon Humber
1713
At 20, finishes his first pendulum clock — made almost entirely of wood
1735
Brings H1, his first sea clock, to London; it sails to Lisbon in 1736
1759
Completes H4 — a watch just 13 cm across that beats the whole problem
1773
After petitioning King George III, Parliament awards him £8,750
1776
Dies in London on 24 March — his 83rd birthday
By the numbers
The measure of him
5.1s
Time H4 lost over 81 days at sea, England to Jamaica, 1761–62
19
Years he spent building a single machine, H3, from 1740 to 1759
£20,000
The prize set by the Longitude Act of 1714 — never formally awarded to him
43
Years from his first longitude design (1730) to Parliament's award (1773)
What he built
The work
1713
A clock of wood — oak wheels and pinions of lignum vitae, a tropical hardwood oily enough to run without lubrication.
c. 1722
The Brocklesby Park turret clock, built for a Lincolnshire estate. By the estate's account, it is still keeping time three centuries on.
1720s
The gridiron pendulum and grasshopper escapement — brass and steel rods that cancel each other's expansion, and an escapement with almost no sliding friction.
1735
H1, a 34-kilogram brass sea clock with linked balances that rode out a ship's motion. On the Lisbon voyage it corrected the master's reckoning.
1759
H3, which introduced the bimetallic strip and the caged roller bearing — two inventions still in everyday machines today.
1759
H4, the sea watch: 13 cm across, about 1.45 kg. A copy by Larcum Kendall went round the world with Captain Cook, who called it "our trusty friend the Watch."
Doubted, then vindicated
Recognition
In his lifetime
A self-taught craftsman facing a Board of Longitude weighted with astronomers
After H4's triumphs, made to strip it down before a panel of experts, and surrender his clocks, to win £10,000
Astronomer Royal Nevil Maskelyne championed the rival lunar-distance method
Had to appeal to the King at 79 to be paid more of what he was owed
Today
H1–H4 are displayed at the Royal Observatory, Greenwich
A memorial stone in Westminster Abbey, unveiled in 2006
Dava Sobel's Longitude (1995) made him an international name
"Clock B," built to his late principles, set a Guinness record in 2015: 5/8 of a second off in 100 days
The carpenter's village
Barrow upon Humber
His family moved to this Lincolnshire village on the south bank of the Humber estuary when he was a child. There he learned his father's trade of carpentry, led the church choir, surveyed land — and, with his brother James, built clocks with no formal training at all. The tidal estuary at his door ran out to the North Sea and the ships whose problem he would solve.
1713
His first wooden clock, made here at 20
c. 1722
The Brocklesby Park turret clock, built nearby
1735
He leaves for London with H1
"I think I may make bold to say, that there is neither any other Mechanical or Mathematical thing in the World that is more beautiful or curious in texture than this my watch or Time-keeper for the Longitude."
— John Harrison, of H4
