13 October 1884: Greenwich adopted as the prime meridian
On this day in 1884, Greenwich was chosen as the prime meridian of longitude, settling the matter of time once and for all.
Before the industrial revolution, time was a fairly local thing. When the sun was at its peak, it was around midday. Everybody was happy.
But the arrival of the railways changed things. Even in Britain, the difference in time between the most easterly and westerly points is around 30 minutes. For large places, it could be hours. This played havoc with timetables. In the USA, for example, each railway company worked to its own clock, set at the location of its head office. Nobody knew which train was due when. Clearly, this could not go on.
Time was also crucial for navigation. Latitude was easy enough to reckon, but working out your longitude meant you had to know the exact time both at the place you happened to be, and at a fixed spot somewhere else.
One problem was that nobody could quite agree where somewhere else should be. Britain used Greenwich. France used Paris. Others used Cadiz, or St Petersburg. People had been trying to standardise time for years, but nobody could agree. And so, to settle the subject once and for all, in 1884 a conference was called by the president of the USA, Chester Arthur.
On 13 October, 1884, the International Meridian Conference resolved by 22 votes to one, and two abstensions (one of which was France, obviously), that Greenwich would be the prime meridian of longitude. It was, after all, the most practical solution. Around 65% of the world's ships already used it; America used it; the British Empire used it. All of those people were hardly going to start using Paris, now, were they?