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    Re: "A history of marine navigation" by Per Collinder, and Neckam
    From: George Huxtable
    Date: 2009 Jul 17, 18:29 +0100

    I had questioned Collinder on the accuracy possible with pendulum clocks on
    land in the mid 1700s, and Ken added-
    |
    | 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.
    
    Quite so.
    
    I doubt if that claim for one second in 100 days, for Harrison's regulator
    clocks, is accepted by all authorities, but he had certainly made great
    strides in the precision of pendulum clocks.
    
    Tompion's earlier clocks suffered from being before the days of
    temperature-compensation of the pendulum.
    
    George.
    
    contact George Huxtable, at  george{at}hux.me.uk
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
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