NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Classification of the methods for clearing the Lunar Distances
From: George Huxtable
Date: 2003 Apr 9, 12:40 +0100
From: George Huxtable
Date: 2003 Apr 9, 12:40 +0100
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@huxtable.u-net.com, by phone at 01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. ================================================================