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Hi George

I make the error in displacement to be 18.54 miles further west.  Allow me to explain.

The miles for one degree of longitude, at latitude, can be found by 

    A = Cos(latitude)*60.   {Dutton, article 202}

So for the equator, we have 60 miles for one degree.  Then we can determine 
the number of miles in 15 degrees, 15*A.  For the equator this is 900 miles.

    B = A*15

Since 15 degrees in longitude is one hour, we can resolve the number of miles per second

    MPS = B/3600

For the equator, this resolves to 0.25 miles per second.  Inverting, we get 4 
seconds per mile, that familiar saw.

Now let me insert the latitude of Cape Belsham on Elephant Island.  

    A=Cos(61.10611)*60 = 28.991 miles for one degree of longitude
    B = 28.991 * 15 = 434.870 miles for 15 degrees
    MPS = B/3600 = 0.12079 miles per second
    Inverting, we get 8.279 seconds per mile

Finally, we have Worsley's (to him unknown) chronometer error of 2 minutes 
33.5 seconds.  This is 153.5 seconds.  Divide 153.5 by 8.279 and you get 
18..54 miles.

We can see the result of this on 8 May1916, when he makes his position to be 
South 54 degrees 19 minutes West 39 degrees 36 minutes.  He should be able to 
reach out and touch South Georgia Island.  Yet he cannot see it.  At 12:30 
that day, he finally does,  at an estimated distance of 9 miles.  

Best Regards
Brad



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