What time is it?

Two days ago, I would have no idea what this beautiful machine was. Well, I could probably guess it was some kind of clock, but I wouldn't know why it was so important -- and important it is, my friends. This is John Harrison's first chronometer -- a clock made especially for keeping true time on a ship at sea, and his first contribution towards solving the longitude problem that plagued sea captains for hundreds of years.

The problem is basically this: It is easy to figure out your Latitude (the horizontal one), because it is all determined by the poles and the equator and you can just look up at the sky and know where you are. Longitude is harder because those lines are arbitrarily set by people -- in fact, until the late 1700s, the prime meridian would change depending on who was measuring and who was in charge, and it wasn't until 1884 that it was officially placed in Greenwich (and even later for the French to give up the Paris meridian). To figure out your longitude, you need to know how far away you are from where you started. A good way to do this would be to know what time it is exactly at your home port, and then compare it to the local time on the ship (which you can easily tell at noon when the sun is directly ahead). Since time and distance are closely related, you've got your location. But, for most of sailing history, people either used sundials, pendulum clocks (waves and pendulums don't mix), or pocket watches that could gain or lose minutes at unpredictable rates depending on the temperature and humidity, and which completely stop when they wind down.

If you don't know your longitude, you have a pretty good chance of completely missing your target, or ramming your ship into some other target and sinking the whole thing. Most people solved this problem by running all their ships on the set shipping routes that everyone else used. The problem with this is that pirates and rival countries know exactly where your riches-filled ships are and they can just take all your stuff. That is no good. So, figuring out the longitude problem was so important to the British government that they made a prize of a kings ransom (which would be like millions of dollars in modern monies) to whoever could solve it. Then they made a panel of judges who would review the proposals.

The problem, for John Harrison, is that most of the panel was made up of astronomers, and astronomers thought that the longitude problem should be solved by astronomical observation, not by some silly mechanical clock. This set up a decades long struggle between the clockmaker and the star-watcher, both struggling to get to the prize money first.

And why I am now an expert in said longitude problem? Why it is because I just blasted through Dana Sobel's very readable book Longitude: The True Story of a Lone Genius who Solved the Greatest Scientific Problem of His Time. Earlier this year I read Galileo's Daughter, also by Sobel, and I really enjoyed that one as well. History of science is basically awesome if you can find someone that can flesh out the characters and explain the scientific bits in a way that anyone can understand. Sobel is that kind of author.

Harrison eventually made four other chronometers (there are pictures of them at the "longitude problem" link above, which links to a truly awesome site at the National Maritime Museum). And, after decades of work, the British monopoly on chronometers arguably allowed them to rule the seas and expand into that oh-so-popular British empire one is always hearing about.