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    Re: the Shovell Disaster
    From: Ted Gerrard
    Date: 2007 Nov 12, 15:20 -0000

    Nicolas wrote

    ....what I would like to know is if it was explicitly written down that those 7 observations were
    done using back-staffs.

    Reply from Ted
    As I said before, I have absolutely no idea, or at least no hard evidence that any of the navigators in the Shovell fleet specifically used back-staffs to take any of those 7 noon sights on that fateful day. However most certainly at least one ship in the fleet carried _quadrants_ ... Sir William Jumper, (a member of the Paramore Court Martial sitting in judgement on Edmond Halley's first officer, Edward Harrison) captain of the 70 gun Lennox.

    The term used by Jumper is discussed by May (Naval compasses in 1707, p409) who was of the opinion that Jumper may have been referring to a Davis Quadrant or Backstaff.

    Edward Harrison, for all his faults a brilliant navigator and certainly as good as any in the RN bar Halley prior to his dismissal by Shovell), made very good use of a back-staff fitted with a Flamsteed lens (invented by Robert Hooke) during the first Paramore expedition in 1698.

    Ted Gerrard


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