In 1737, John Harrison, a self-taught clockmaker from Yorkshire, stunned London’s scientific establishment by presenting an idiosyncratic solution to the most important and notorious technological problem of the 18th century. He was hoping to win a then-fabulous prize of £20,000 (about £5m today) for anyone who could devise a way for a ship’s navigator to determine its longitude and therefore its position at sea. Harrison’s approach was to build a clock that would keep Greenwich time faithfully; by comparing local time (measured using the position of the sun) with the time in London, the navigator would know how far east or west the ship had sailed. The theory was sound, but given the rolling of ships and changing temperature and humidity, the leading scientists of the day – including Sir Isaac Newton – reckoned that a sufficiently accurate clock would be impossible to build. Harrison proved otherwise.

The longitude prize, sponsored by the British government, was not unique. Prizes were also offered in France for a functional water turbine, and for a method of preserving food for Napoleon’s armies. The latter prize quickly inspired the tin can, more of a blessing than food snobs might acknowledge.