Why Longitude Mattered
For centuries, sailors could tell how far north or south they were by measuring the sun or stars. Latitude came from nature and was relatively easy to find. Longitude was different. There was no natural starting line, and a ship at sea could only find its longitude by knowing the time at its current location and the time at a fixed place back home.
That difference in time gave the answer because the Earth turns fifteen degrees each hour. If local noon on the ship came two hours later than noon in London, the ship was thirty degrees west of London. The idea was simple, but the tools were not. No clock in earlier centuries could keep steady time on a wet, rocking ship that moved through heat, cold, and storms.
The cost of this problem was terrible. In 1707, Admiral Sir Clowdisley Shovell’s fleet struck rocks near the Scilly Isles after a fatal mistake in position, and nearly two thousand men died. Other voyages dragged on for weeks or months because captains had to search blindly for land. Those delays often turned scurvy into a death sentence, as happened on George Anson’s voyage, where men died while the crew zigzagged in search of a supply island.
The problem also affected trade, war, and empire. Ships stayed on a few familiar routes because they could not trust their east-west position, which made them easier targets for pirates and enemy fleets. Nations lost money, cargo, and sailors. Britain finally treated longitude not as an abstract scientific puzzle but as a national emergency.
Full summary available in the Readsome app
