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Bruce:

"The American Practical Lunarian and Seman's Guide" was authored by one
Thomas Arnold, and was published at Philadelphia, PA, in August 1822. I
believe my copy, which has been in my possession for over 60-years,  is
one of very few remaining. There is a copy in the Library of Congress,
and one was offered for sale some years ago on the internet - otherwise
the book appears relatively unknown, although it treats the subject of
Lunars, at least in my opinion, better than do either Bowditch or Norie.

According to the book itself, Thomas Arnold operated a Nautical Academy
at 295 South Front Street where he, and I quote ... " Continues to
instruct gentlemen designed for and engaged in a seafaring life, in
Navigation and Lunar Observations, ascertaining the Longitude by
Chronometers ..." etc.

On Wed, 21 Apr 2004 23:47:25 EDT Bruce Stark  writes:
> Henry,
>
> Thanks for getting down your old vernier octant to check my notion.
> Looks
> like my 15� interval idea doesn't fly.   But now I don't think it
> was of any
> consequence. All that would be required for such a blunder would be
> that the 60�
> engraving would be on the part of the arc Lewis would have seen in
> the opening
> of the index arm.
>
> As I recall, the moon was not long past full at the time of the
> observation.
> But George considered the wrong limb possibility and several other
> List member
> examined it too. It doesn't explain anything, not by itself anyway.
>
> Quite a few graphical and mechanical methods of clearing the
> distance were
> invented. Seems like one was mentioned in an edition of Maskelyne's
> Requisite
> Tables. Janet Taylor invented one. Maybe it will come up in the
> Greenwich
> lecture on Mrs. Taylor that George posted us on.
>
> I'd never heard of Arnold's Lunarian before. Sounds interesting.
>
> Bruce

   

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