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George H, you wrote:
"Certainly Lecky,  writing of the British navigational tradition, considered
longitude-by-lunars to  be a matter of history, in 1879."

Of course, even a man like Lecky, fully  aware that lunars were dead and
buried, also wrote some very interesting  practical comments on lunars over the
course of something like six or seven  pages in his book. Interest in lunars,
either from a technical/mathematical  standpoint or a lunarian romantic
standpoint, has never died out, and we find  them entertaining today. But by 1879,
they were apparently no longer in use by  practical navigators and handn't been
aboard Royal Navy vessels since the 1820s  or so.

From Randier (in translation), you quoted:
"Seamen have  always detested calculations with pencil and paper, preferring
to use  diagrammatic means."

I consider this seriously unhistorical. Diagramatic  methods caught on VERY
slowly in celestial navigation. There was a significant  bias in favor of
calculation (meaning columns of numbers, added and subtracted)  in 19th century
navigation. Perhaps Randier was simply extrapolating backward to  those earlier
days the very modern preference for crossing lines of position. As  for the
"planisphere" that you say accompanied these words, how accurate do you  suppose
it was? There were lots of these mechanical contrivances invented over  the
years, and it seems as if every inventor thought that he had brought some
wondrous relief from the terrible drudgery of working lunars. But in fact, it is
largely myth that lunars were painfully tedious to work out. From the earliest
period there were very good methods of working lunars that require only about
 three times as much work as an ordinary time sight, and they are very
similar in  calculational procedure to time sights, too. The calculational
"difficulty" was  not a showstopper, and "planispheres" for solving navigational
problems (beyond  star identification) were oddities. And that's part of the reason
that these  "weird inventions" have survived in museum collections.

And you  wrote:
"Both Frank and I would argue with that assessment of the lunar  distance
method as being 'in constant use between 1880 and 1910' "

That's  for sure. To me it strongly suggests that Randier had no clue what he
was  talking about. Arguably reasonable dates for the French 'constant use'
of lunars  would be 1780 to 1810 --a FULL CENTURY earlier. Makes me wonder
whether the  author might simply have mis-read his notes when he was compiling his
book. How  can you place ANY value on a source like this (on lunars
specifically, that  is)?

"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."

The evidence that I have mentioned on this list is  an important component of
the material I have examined, but it ain't the whole  boatload! For French
primary resources, I would love to examine logbooks and  navigation notebooks.
Perhaps someday I'll have that luxury. Nonetheless, I have  read some primary
French sources from the era, and I highly doubt that French  usage of lunars
lasted any later than British usage. I will make this claim:  that French usage
of lunars was essentially synchronized with British usage plus  or minus a
decade. And I would put money on it! This year, the US mint has  issued coins
with genuine lunarians (yes, men who understood lunar distances) on  both the
obverse and reverse. I will bet twenty of these valuable coins that the  dates I
have suggested are closer by at least 50 years than the dates Randier  has
suggested [ please understand this 'bet' is just for laughs-- for  those of
you who have not figured it out, the "minted lunarians" I am referring  to are
Thomas Jefferson and Lewis & Clark on the latest US nickel. My  "twenty
valuable coins" amounts to one whole US dollar, and no more (I believe  in
gentlemen's bets but not otherwise)].

I would love to see real  evidence --not just some late 20th century author's
unsubstantiated claim-- that  I am wrong on this point. If you're interested,
I can point you to contemporary  (late 19th century articles) in French
decrying the complete obsolescence of  lunars at sea and their "nearly forgotten"
status.

-FER
42.0N 87.7W,  or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars

   

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