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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: "A history of marine navigation" by Per Collinder, and Neckam
From: Ken Muldrew
Date: 2009 Jul 17, 09:32 -0600
From: Ken Muldrew
Date: 2009 Jul 17, 09:32 -0600
On 17 Jul 2009 at 10:35, George Huxtable wrote: Some of what Collinder writes should be taken with a pinch of salt. For > example, in the extract Frank quoted in [9078], Collinder referred to the > requirement for a timekeeper for the longititude prize as "an average > error > of less than three seconds (of time) a day., adding - "There was no > pendulum > clock on land capable of that.". That last bit's nonsense. There had been > many regulators, in observatories, with much better performance than > that, > such as Tompions's great clocks at Greenwich, built 70 years earlier > (which > still survive). In WJH Andrewes "Quest for Longitude" there is a chapter on Harrison's regulators by Martin Burgess where it is claimed that he was able to keep time to one second in three months; the limit achievable with a pendulum in air clock. I don't think Tompion's regulators ever went better than 2 seconds per week, but that figure is from memory and could very well be wrong. Ken Muldrew. --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---