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.

Pratchett and Time

[Bonker]

I saw the special about Harrison and his clock just a few days after I read 'The Theif of Time', arguably one of Pratchett's better books of the aging Discworld series. Not surprisingly, the non-plot themes are somewhat similar... the quest for the perfect material with which to build clock springs.

Reading about this makes me want to read it again.

Re:Longitude

[rhysweatherley]

It was on the ABC in Australia last year, starring Michael Gambon and Jeremy Irons. A BBC series originally I believe.

It was one of the best science-related history shows I've ever seen, tracing the story of H1 through H4 in a way anyone could appreciate.

The show also told the story of the WWI soldier, emotionally damaged by his war experiences, who painstakingly restored the clocks in the early part of the 20th century.

It's amazing how much we owe to Harrison. It's a pity that he had to fight so hard for his compensation, because the upper-class science types of the time refused to believe that a cabinet maker could come up with the solution.

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:The remarkable, unique Harrison clocks

[Ben Jackson]

The interesting thing about the Harrison clocks, is not only were they the GPS of their day, they were also the atomic clocks of their day.

Not only is GPS the GPS of today, GPS is also the atomic clock of today. And a great source of accurate time if you want to run NTP on an isolated network.

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.