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Centuries-Old Longitude Clock Runs Again

Posted by Hemos on from the and-the-old-shall-become-new-again dept.

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 .

10 of 144 comments (clear)

  1. H.4 Timepiece Background by BrianGa · · Score: 5, Informative

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

  2. Pratchett and Time by Bonker · · Score: 3, Informative

    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.

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  3. Re:Longitude by rhysweatherley · · Score: 3, Informative
    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.

  4. Re:H.4 Timepiece -- ERRORS by hugecyberpenis · · Score: 1, Informative
    First of all, your references pertain only to the 1st version, NOT to the 2nd (or 3rd or 4th). To really determine the significance of this, one needs to look at better sources. See:

    Former demonstrations at Antioch

    Pluaralism and the Last Century; implications on H.4

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  5. good example of a disruptive technology by jgg · · Score: 5, Informative

    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

  6. Re:The remarkable, unique Harrison clocks by Ben+Jackson · · Score: 3, Informative
    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.
  7. Movies vs. History by Bolen · · Score: 2, Informative

    I confess I haven't seen the movie. I hope the movie didn't say the first 3 clocks didn't work at sea.

    The H1 worked quite well during its sea trial. Harrison could have won the Longitude prize based on the trial of the H1 if he hadn't been such a perfectionist, and declared he could do even better, thus putting off an immediate financial gain. By the time the H2 was ready, there was a change in leadership at the Royal Observatory, now hostile to Harrison's efforts.

    (I'm writing this from memory, so I don't remember the details. I believe at least 3 of the clocks were tested at sea, some under conditions intended to make them look bad, such as not being wound consistently.)

    1. Re:Movies vs. History by twitchkat · · Score: 2, Informative

      According to the movie, the first H1 was effective at sea, but not up to the inventor's desires.

      I'm not sure if this was added for drama or not, but the plot went like this: SPOILER? his calculations differed from the captain's calculations at a critical point in the voyage.

      Disagreeing with the captain at sea was not a good idea at the time -- it would have been considered mutiny.

      They were following the captain's calculations, but they had the inventor's concerns in mind. Because of these concerns, they were able to determine they were in fact off course before it was "too late" and were able to change to a safe course.

      The captain chose not to put this incident into the ship's log, so the inventor had no evidence of this until a first mate came forward.

      The inventor then got the funding to continue development with the H2, where more significant accuracy issues were discovered...

  8. Re:Longitude by Graymalkin · · Score: 4, Informative

    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.

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  9. More the rage than you might think by tdyson · · Score: 2, Informative

    Mechanical watches are made by dozens of companies today, including Swiss Rolex, Omega, IWC and dozens of others, even Swatch. Even Seiko makes mechanicals (although mostly for the Asian market). The Chinese make a bunch of cheap movements and the Russian company Poljot makes an interesting line of affordable watches. Accuracy ranges from +/- 1 second per day on high-end Swiss watches to +/- 20 seconds per day on the Russians. In general anything under +/- 6 seconds per day is considered good. However, there can be a great deal of variation from watch to watch. Rolex, Omega and other mass market companies do little or no hand work in their mass market lines. When you get to a company link JLC, and others, every watch gets some hand fit and finish. However, none of them can be wound only once per month. Most have about a 40 hour power reserve. A few have an 8 day reserve (notably an IWC, and an Eberhard. Of course just about every company offers an automatic watch that is wound by the movement of the wrist through out the day. Those watches should "never" need winding if worn every day or two. Everything you ever wanted to know about mechanical watches can be found at Timezone. Be forewarned, most of these guys think of watches under about $5,000 as "mid priced".