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    Re: Sextant averager
    From: Douglas Denny
    Date: 2010 Oct 11, 08:41 -0700

    Gary wrote:-
    "Here is the patent on the Dreimel-Black averager used in the Kollsman
    sextant. The patent used an A-10 sextant to illustrate the invention".
    ------------

    Most interesting indeed. Using a ball/disc integrator in a sextant. I note the patent is for 1950 which fixes the date precisely for this development. Hughes uses the same principle. Coincidence? I think probably not.
    --------

    Ball and disc or ball/cone integrators were a well-known mechanical method of making "computers" for maths calculation. The planimeter for measuring under graph curves was invented in 1814; and the ball/disc integrator which is a development of the planimeter principle was invented by the brother of Lord Kelvin in 1886. Lord Kelvin used it in his Harmonic Analyser for calculating tides.

    Douglas Denny.
    Chichester. England.
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