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    Re: timepiece history - when did second accuracy become feasible
    From: Greg R_
    Date: 2007 Oct 28, 09:58 -0800
    > The concept of a second of time, a minute of time as
    > fractions of an hour and of a day.  I wonder what civilization
    > had the thought to breakdown the hour and what reasonable
    > technology was available. 
     
    I'll leave the discussion of what technology was available (and when) to others with more resources (and more time...  ;-)).
     
    But as I understand the concept, dividing the day up into hours was considered to be "accurate enough" for civilization a couple hundred years ago (i.e. "We're expecting Caroline to arrive on the hour"). Then when it became necessary to divide time into finer increments, the term "minute" was coined (as in "extremely small"), and when a further division became necessary it was called the "second minute" (later shortened to just "second" as we know it today).
     
    Wonder what they'd think of our nano-, pico-, and femto-seconds (etc.) that are in common use today?
     
    > Among my faults, is a tendency to fall into survival mode
    > thinking.  What if no  battery powered timepieces, no
    > computers (i.e) back to computing by hand trignometric
    > tables.
     
    What you call a "fault" I'd consider to be an asset - someone with that "what if" mentality and mindset would be more than welcome on any crew that I was a part of.  :-)
     
    --
    GregR
     
     
    ----- Original Message -----
    Sent: Sunday, October 28, 2007 7:31 AM
    Subject: [NavList 3676] timepiece history - when did second accuracy become feasible


    This is a multipart question so I hope that I dont leave
    something unasked as to the scope.

    The concept of a second of time, a minute of time as
    fractions of an hour and of a day.  I wonder what civilization
    had the thought to breakdown the hour and what reasonable
    technology was available.   My quess is the water clock with
    the drip set to 60 per minute but this is pure speculation.
    I also have to wonder what drove the person who decided
    that subdividing the hour was necessary.   Perhaps even
    the concept of a second was quite the leap.


    Since the length of the day changes throughout the year, some
    technology perhaps sundials, or again water clocks made the
    observer aware that measuring an hour with some measure
    of accuracy was desirable.  I know that on ships a sandglass
    was used to to time watches.

    Although Harrison was among the first to make a timepiece
    of sufficient accuracy for use at sea,  I wonder how much
    earlier land based timepieces were up to the task.

    Among my faults, is a tendency to fall into survival mode
    thinking.  What if no  battery powered timepieces, no
    computers (i.e) back to computing by hand trignometric
    tables.

    Peace


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