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George Huxtable wrote:
>
> I disagree somewhat with Gordon Talge, who wrote-
>
> =======================
>
> >PS: The British, and rightly so, complained bitterly about us
> >"up starts" ripping them off, with copyright violations. We copied
> >without regard, by reprinting tons of British
> >books and documents. It was kind of a sore in their side.
> >
> >The British Navy, in spite of America's victories in Revolutionary War
> >and in the War of 1812, was still the best in the world and we knew it.
>
> =====================
>
> Although what Gordon says may have been true in many respects, it did NOT
> apply to the provision of almanac information, from 1855 onwards, which was
> the topic we were discussing.

Without doing any real research on the exact date of changes in the
American Nautical Almanac, and I will take that 1855 was a pivotal year,
I do know that American Nautical Publications relied heavily on
British Admiralty Publications. We did not come really into our own
until after the American Civil War ( or as us Southerns like to say,
the War for Southern Independence ). Simon Newcomb was, if I remember
right, the main man that really advanced the Nautical Almanac Office.
A top notch astronomer.

I do know that in one of the navigation books I have,
John Hamilton Moore's "New Practical Navigator" 1798, he complains
about Americans copying his books without permission and the other book,
Andrew Mackay's "Complete Navigator" 1807 is a unabashed copy, printed
in Philadelphia of a British edition.

>
> As for other matters raised by Gordon-
>
> >It would seem to me that by 1855, having the correct time via
> >accurate chronometers was not really much of an issue, if you
> >could afford a good one. I think that doing Lunar Distances at sea
> >was not that common.
>
> Unless they had a full kit of three chronometers (and few ships did) then
> there was no check a prudent mariner could make, to ensure that his
> tick-tock, with its pivots and gears and escapement, had not been affected
> by a bit of grit in the wrong place. Not without making the occasional
> lunar-distance observation. Chauvenet is emphatic, in 1868,  about the
> importance of this matter for US Navy vessels.
> >
> >They may have been done on land or in port for getting time in
> >isolated places, but I think the Noon Sun Sight ruled, and maybe
> >still does. It is the easiest to do, and requires the least
> >calculations.
>
> The Noon Sun Sight gives latitude accurately, but not longitude, even if a
> chronometer provides precise Greenwich Time. Some sort of Time-Sight, at a
> time OTHER than noon, is required before precise longitude can be deduced.
> We have discussed that matter at some length on this list in the past.

While it is true that you can't get longitude from a Noon Sun Sight, it
still was the most popular. Ex-Altitude Sights were also done, but
I don't think that LDs were that popular. There are ways around knowing
your exact position and still hitting your target. I remember hearing
that
Emila Erheart  flew from South America to Dakar, Senegal. Her
navigator wanted to head 50 miles North of Dakar and when they hit the
African Coast turn right and follow the coastline down to Dakar, which
sounds good to me. Emila had her own ideas and turned left instead,
putting them way off course and set them back a day or so. She probably
didn't listen to her navigator in the Pacific either.


> >I don't think that 30 seconds difference would be that big of
> >a deal between the British and American Almanacs, LD's seem to
> >me to be very hard to do right and accurate, especially on board
> >a ship.
>
> Well, we can agree with Gordon that LD's are very hard to do right and
> accurate, especially from a sailing vessel at sea, with violent motion of
> the deck and most of the sky obscured by sails. But however well or badly
> they are done, errors in the almanac always increase the overall possible
> error, making an uncertain observation even less certain. A 30-second arc
> error is enough to add an uncertainty of an extra 15 miles to the
> longitude, in equatorial waters. Well worth eliminating, when that's
> possible. And the American Almanac showed, from 1855, that it WAS possible!
>
> Astronomy, it seems to me, was the earliest scientific endeavour in which
> the new nation of America showed that it could compete on equal terms with
> the rest of the world. And Chauvenet was an important figure behind making
> that happen.
>
> George.

This is true, but although we were a important power, we really didn't
come on to the world's radar screen until about 1898 and didn't really
come
into our own until World War II.

I know that in mathematics, Europe was the place to be. Germany, France
and
Poland in particular. Almost all scientific papers, whether written by
Germans or not where written in German. In the 1930s as the turmoil and
oppression of war was starting, many, many European Mathematicians and
Scientists came to America. The scientific language switched from German
to English.

Of course, the British, as we now know invented the first computer
to break the German codes and made advances in Radar that was critical
to the war effort, so not everything moved the America by a long shot.

There was a man named R.V. Jones who wrote a book called "Wizard's War"
that focues on science in Britain during the war.

As an unrelated side bar. It is interesting to note that one of the
largest, if not the largest publishers of mathematics books is the
German publisher "Springer Verlag". They publish in English, German,
French and who know what else. I have maybe 50 of their yellow books.

To sum my ramblings up. I don't think that LDs were that poplular. There
were hard to do right and required a lot of calculations. Knowing your
EXACT position at sea was not that critial. Only near land is it a
EXACT postion critical. That is where the ships get wrecked on rocks
and reefs, etc. Note that by 1917 LDs were dropped from the NA.
I would say that it is a case of "theory vs practice".

-- Gordon

PS: It has been a while, but I did read most of Chauvenet's book. It is
excellent.

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| Gordon Talge WB6YKK         mail: gtalge AT silcon DOT com |
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