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Frank Reed referred to-

| ... a navigation workbook dating from 1886 from a (UK) navigation  class.
| The seller has posted almost thirty images of pages many of which are  clearly
| legible. These are examples of the practice of navigation teaching,  rather
| than the practice of navigation. So, for example, there are several  examples of
| working lunars (by Thomson's tables) despite the fact that they were
| essentially obsolete by this date. But they're still interesting!

The question of obsolescence of lunars by 1886 may be one of Frank's "sweeping statements", though I
wouldn't disagree with it in general. Certainly Lecky, writing of the British navigational
tradition, considered longitude-by-lunars to be a matter of history, in 1879.

But there are other maritime traditions, and other views. In this respect, I would like to bring to
the list's attention a book, "Marine Navigation Instruments", by Jean Randier, published in French
in 1977, and in English translation in 1980. I don't think it's been discussed on this list before.
Essentially, it's a picture book, though one which offers a full description of each illustration.
The linking chapter-text between the pictures is briefer than I would wish. Because it describes
instruments from a very French viewpoint, there are many devices shown, sometimes quirky ones
according to French tradition, that are missing from other English-language accounts. So it's worth
taking a look at. The descriptive text is generally good, and to-the-point, but not infallible.

Randier has some interesting things to say about the use of lunars in French vessels. He shows (fig
150) an undated plotting instrument, "Planisphere pour les distances lunaires" (planisphere for
lunar distances), a sort-of drawing-board carrying a calibrated turntable marked with a grid
pattern. The text states- "Seamen have always detested calculations with pencil and paper,
preferring to use diagrrammatic means. Indeed, our generation is acting true to form in adopting
pocket calculators. It was natural that a graphic instrument should come into being during the
period when the lunar distance method was in constant use, between 1880 and 1910. The planisphere
illustrated was designed by Hue, a professor of hydrography, and bought by the French Naval
Ordnance."

Both Frank and I would argue with that assessment of the lunar distance method as being "in constant
use between 1880 and 1910", particularly in view of the statement, elsewhere in that chapter, that
the French "connaissance des Temps" discontinued lunar distances in 1904.

We should also consider another statement, on page 183, in a passage dealing with chronometers,
where one finds this-

"In 1832, the French Naval Ordnance listed 143 chronometers, by Rerthoud, Breguet, and Motel
exclusively. The merchant navy still possessed none, and would not until about 1880."

That comes as something of a surprise, and I wonder how the "merchant navy" was defined, and doubt
that French merchant vessels would lack chronometers until so late a date. Particularly in view of
the fact that the French were so much to the fore in the development of marine chronometers, in the
late 1700s and early 1900s. I wonder if any of the list's French readers can offer more insight.

We have to regard it as possible that different maritime traditions continued using lunars later
than others, just as it seems that some groups of mariners may have adopted Sumner navigation
earlier than others did.

Frank's assessments may be coloured by his concentration on the logs of American vessels,
particularly whalers. Things may not be quite the same the whole world over.

George.

   

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