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    Re: Lost people DO follow circles, says research
    From: Douglas Denny
    Date: 2009 Aug 22, 17:45 -0700

    Oh curmudgeonly one of little faith!
    It is as I said.
    A mirror mounted on the vehicle allowing a good view behind.
    
    The expedition was the Australian Antarctic Research Expedition in 1960.
    
    It seems they were cleverer than the Brits with their expedtition when they 
    were putting out sticks to steer by, and did not like getting out in the 
    freezing cold to pick them up again in all the snow and ice and so devised 
    this method.
    
    I note having read it again they used a stick on the vehicle for reference in 
    the line of sight of the view of the mirror: effectively doing the same job 
    as getting out playing around with sticks in the snow.
    
    Appparently they could track within + or - half a degree.
    
    Quite a simple clever idea.
    See the enclosed pdf file.
    
    Douglas Denny.
    Chichester. England.
    
    =====================
    
    Original Copy:-
    
    Douglas Denny wrote, in ]9852]-
    
    "In the 1950s (or was it 60s - can't remember)  the Antartic expeditions
    using caterpillar tracked vehicles to get to the Sotuh Pole used a mirror
    set-up in the driver's vision of the front vehicle, to enable him to look
    backwards so the driver could look back along his track made in the snow,
    and thus keep a straight line ahead.  It was very effective apparently as he
    was making a continuous back-bearing on his own tracks with which he could
    see immediately if he veered off track."
    
    ========================
    
    I presume Douglas Denny refers to 1958, when the trans-Antarctic expedition
    were trying to get from, not to, the South Pole, in the last stages of their
    crossing. This took the party near the South Magnetic Pole, when their
    magnetic compasses (at least, those aboard their tracked vehicles) became
    useless, and with sky overcast, the Sun position was of no help..
    
    My reading of the technique, as described by Fuchs and Hillary in their book
    "The crossing of Antarctica", bears little relation to that description
    given by Douglas Denny above. I can find no mention of using alignment, in a
    mirror, with the vehicle's own tracks, as he described. If it's there, or
    perhaps in an account of another expedition altogether, a reference would be
    helpful.
    
    Having somehow established an intended direction and marked it with a pair
    of flags, they continued it indefinitely by having a collection of marker
    flags carried in the leading vehicle. Before the flags behind them had
    disappeared from sight, one of the team would get out and place a new marker
    precisely aligned with those that had gone before. In this way, they kept a
    chain of four flags constantly in view. As I see it, three flags would have
    sufficed, but no doubt four provided belt and braces.
    
    The flags, when no longer needed, were collected by the trailing vehicle,
    and eventually recycled.
    
    In this way the straight path could be extended on and on, and a large
    radius of curvature could be maintained. The angle-of-bend, at each new
    flag, was kept small, being limited (in radians) to the error in aligning
    each new flag with its predecessors, divided by the spacing between the
    flags. Hopefully, that error would not always be in the same direction, but
    inevitably, an error in direction would accumulate. However, the sky cleared
    after about 100 miles of travel had been accomplished by this technique.
    
    George.
    
    contact George Huxtable, at  george---me.uk
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
    File:

      
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