|
|
Subject: Re: Classification of the methods for clearing the Lunar Distances
From: George Huxtable (george@XXX.XXX)
Date: Wed Apr 09 2003 - 07:40:59 EDT
Herbert Prinz said, of Bowditch-
"I came to realize that it was the general trend of this publication after
the death of Bowditch to let new technology mature for a quarter of a
century before taking it into consideration. (First brief mentioning of
Sumner line in 1855, intercept method around WWI)"
It's not the only publication to behave in that way.
I have recently acquired a copy of "Navigation and Nautical Astronomy", by
J R Young ("formerly professor of mathematics in Belfast College"). This
copy was published as one of "Weale's Scientific and Technical series",
"New Edition 1903". This was the Young behind Young's method for clearing
the lunar distance, referred to in Cotter.
In itself, Young's is quite a useful little book, with quite a lot of
pertinent information about lunars. This was rather a pleasant surprise, as
by 1903 the lunar distance method must have been quite dead: indeed, within
a couple of years, lunar distances would be omitted from the Nautical
Almanac.
That wasn't the only surprise. The book contains a number of examples of
navigational calculations, backed by relevant extracts from a Nautical
Almanac. The surprise was in the date for these examples and extracts,
which was 1858, 45 years earlier. It became clear that the 1903 "new
edition" was based on an earlier edition of the 1850s, in which the
examples had not been updated.
Delving into the contents provided further surprises. There was no mention
of position lines, or Sumner, or St Hilaire's "New Navigation", which dates
from 1875. Finding a ship's position was described entirely in terms of
obtaining the latitude and then, separately, the longitude: the techniques
of a generation of navigators, long before that "new edition" of 1903. It
appears that little or nothing had been updated for that "new edition".
It seems to me something of a scandal that such a text should have been
peddled at that date, presumably to aspiring navigators who wished to learn
their craft from it. It's relevance in 1903 was largely historical. No
wonder the poor fellows got confused.
George Huxtable.
================================================================
contact George Huxtable by email at george@XXX.XXX by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
================================================================
|