Centuries-Old Longitude Clock Runs Again

douglips writes "BBC News has published a story about John Harrison's H4 chronometer and how it has been wound up for the UK's National Science Week. After 40 years of work [Harrison] proved in 1764 that a clock could be used to locate a ship's position at sea with extraordinary accuracy." Ah, the GPS system of its day. T. adds: This is the timekeeping device which Dava Sobel wrote about in Longitude .

Comments

H.4 Timepiece Background

[BrianGa]

This site tells much about Harrison's H.4 Timepiece (picture). Don't forget to visit the official site.

good example of a disruptive technology

[jgg]

Harrison's sea clocks are a great example of a disruptive technology. His clocks were competing against stellar navigation, and the judging for the award he earned after decades of stonewalling, was done by the royal astronomers. Also - I'm finally posting (my first post!) because for some reason it drove me crazy to read on the main page that it was a clock (singular) that provided a longitudinal position. It takes 2. One set to GMT, the other set to local time, determined by solar noon. The difference provided the longitude. (1 hour = 15 degrees) And it was the ability of H's clocks to keep gmt accurately - (to Jamaica and back!) that made it effective. JGG

Re:Longitude

[Graymalkin]

It wasn't about a cabinet maker coming up with the solution it was the Board of Longitude being top heavy with astronomers who were looking to solve the same problem by another means. The astronomical society was pitching hard for their method because it gave them some clout when asking for grant money to stare at things in a telescope. At the time academia familiar with the longitude problem were classified as Mechanics or Lunars depending on the particular method they supported to solve the problem.