Day 4, Wednesday, June 27, 2018
Our last destination on our fourth day was the Royal Observatory in Greenwich, where you can see the Prime Meridian…
Everybody learns about the Prime Meridian in school, but perhaps you are like me and its significance loses its meaning over time. Short answer: it is critical for the navigation of ships.
For thousands of years, sailing has been a very dangerous business. If you don’t know where you are, you can easily get lost out there in a gazillion square miles of endless ocean. Latitude was apparently easy to calculate. I’m not sure I agree with that statement, but there you go. All you need to know was the calendar date, and then calculate with your instrument how far the sun rose above the horizon that day. Then, you just looked up that information in a book that had already been compiled for you and voila, easy peasy, you know where you are…
The longitude was way harder, and meant that for thousands of years, mariners had been using a method called dead reckoning… Perhaps the emphasis should be on the “dead,” because it was notoriously inaccurate on long voyages where you couldn’t see land. Remember how Columbus thought he was on mainland North America but he was actually on Caribbean islands? Yeah, that. That is actually a fairly successful outcome of dead reckoning.
First and foremost to calculate longitude, you needed to know what time it was. For longitude calculations, you needed to know the exact time; a set standard time, say Greenwich Mean Time. And clocks and watches of the day weren’t particularly accurate or reliable. A few seconds off and you were basically screwed. And when your clock wound down and stopped, who would you ask for the time? Yep… On land, you could ask the neighbor, but out on the open ocean, there was no one around to tell you the time. See? Screwed. Not to mention that all that pitching and rolling on ships made it very difficult for the clocks of the day to work accurately. Longitude was pretty much a matter of having a very accurate, very reliable clock, that would be accurate and reliable even on a ship that was getting tossed around on the open ocean.
The Longitude Act of 1714 attempted to change that accurate/reliable issue. Queen Anne was in power when the Act was passed, establishing a Board of Longitude (sounds like a super exciting volunteer opportunity), and a reward for finding a simple, way to determine longitude that would work on ships.
John Harrison felt up to the challenge and started working around 1727 on such a clock. His work produced four iterations, not always improving, and eventually, in 1761 he tested his fourth clock successfully. There is a lot more to the story than that, but I’ll spare you, since longitude really isn’t that thrilling, even for me.
However, even though his fourth clock was successfully tested, the Board of Longitude for whatever reason decided he should only get half of the prize money, or 10,000 pounds, awarded in 1765. That was a lot of money in the day, but Harrison had been working on this for over 35 years, and was, understandably, pissed. There were also lawsuits because Harrison felt that his methods should be protected, and the Board of Longitude wanted to publish them for mass production. I guess they weren’t super clear about patents and trade secrets when they drafted the act… There were other prizes awarded for other advancements as well, but Harrison made the most significant contribution and won the most money.
So long story short, a meridian is just an arbitrary line set to establish a base from which time can be calculated as you move east or west. It could have been anywhere, and arguments were made for lots of other places, but ultimately Greenwich won out in large part because the Royal Observatory was there, and because of the Longitude Act of 1714 and the fact that prize money was awarded to the winners.
Now, in the days of radar and GPS, the Prime Meridian in Greenwich is more of a tourist opportunity to stand on the line, sit on the line, pose with the line, and say you have been to the place where time begins, arbitrarily… So we did. Just so you know, the jumping photo was Taryn’s idea – that might explain my less enthusiastic liftoff…
The museum also explains all the nuance of calculating longitude, the 1714 Act, displays Harrison’s H1, H2, H3 and H4 prototypes, and other navigational instruments and telescopes. It is pretty interesting! The Observatory also has a pretty nice view of London across the Thames River, since it is located on a hill.
Costs: Royal Observatory – free with London Pass.