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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 .

2 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. 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