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    Re: Lunar eclipse report
    From: Alexandre Eremenko
    Date: 2004 Nov 1, 09:45 -0500

    Dear Herbert,
    Thank you for your interesting information.
    If Ptolemy and Brahe did not use water clock,
    then what did they use for the timing?
    > Ptolemy, on the use of water clocks in antiquity
    > (Almagest, V 14,
    > Translation by Toomer, p. 252):
     "Of the various methods used to solve
    > the latter [i.e. the timing] problem,
    > we have rejected those claiming to
    > measure the luminaries by measuring [the flow of] water [...],
    > since
    > such methods cannot provide an accurate result
    > for the matter in hand."
    > Tycho Brahe picked up the idea, replacing the water by mercury.
    > (Progymnasmatum Prima Pars,
    > Opera Omnia, Tomus II, ed. Dreyer, pp157ff).
    > He makes no quantitative statements about accuracy.
    > Nothing must have
    > come of it, otherwise we would find a description of such
    > a clock in his
    > Astronomiae instauratae mechanica. If you want to blame me of an
    > argumentum ex silentio, I shall take it in stride.

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