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Robert Block wrote-

>I am sure this tread has come and gone, but refresh
>me, if you will be so kind.  Which book on subject
>of Longitude is recommended at this time.
>I list the following two books for convenience,
>there may be others.
>
>Many thanks,
>
>1-The Illustrated Longitude by Dava Sobel, William J. H. Andrewes (1995)
>
>2-The Quest for Longitude : The Proceedings of the Longitude Symposium Harvard
>University, Cambridge, Massachusetts November 4-6, 1993           by William J.
>H. Andrewes (Editor)
>
>Robert Block

================

I have strong feelings on this matter, and I am going to let them show.

In my opinion, judging by my 1995 hardback editionn, Sobel's work is a
despicable little bookling. It leaves the reader understanding little more
about determining longitude than when he started. Partly, this is because
the author has not bothered to include any diagrams. Without diagrams,
there isn't a hope of providing any satisfactory explanation. The only
illustrations are provided for the purpose of decoration, to prettify the
book rather than to illuminate the text.

However, I have to qualify the above comments. I understand that in a later
edition (which I have not seen) the author has sought to incorporate some
much-needed illustrations. If these include explanatory diagrams that
really illuminate the text, and if the text has been adapted to refer to
those diagrams, then that could alter my judgment somewhat.

However, that is not the only reason I dislike Sobel's book. She turns the
search for longitude into a historical romance, with a Hero (Harrison) and
a Villain (Maskelyne). Harrison can do no wrong: Maskelyne can do no right.
And yet, it was Maskelyne's (and Meyer's) lunar-distance technique that the
ordinary mariner continued to use, for the next 50 to 100 years. The cost
of a chronometer could approach the value of his vessel. If he had to trust
his life to longitude measured by chronometer, how could he be sure that it
kept good time? A speck of grit could lead him into life-threatening
danger. He might carry a second chronometer for comparison, but even then,
a discrepancy between the two wouldn't inform him which of the two told the
truth. For that, he needed a third chronometer. These instruments were
unaffordable.

So right up to the time of Joshua Slocum's circumnavigation, the lunar
distance technique continued in (diminishing) use.

In stating the above, I don't wish to belittle Harrison's achievement, not
at all. Although few of his many innovations were incorporated in the
chronometers that followed his own, Harrison showed that accurate
timekeeping at sea could be achieved, when everyone else considered it
impossible.

================

"The Quest for Longitude" as a book of quite a different character. It
stemmed, as did the Sobel book, from a 1993 symposium on Longitude at
Harvard. It's written by a collection of authors, each an expert in his
field, which lends great authority, but also means that the information is
less coordinated than one would wish, with some material duplicated.

It's thorough, detailed, authoritative, factual, sober, satisfying,
well-balanced, beautifully illustrated, well-produced: everything that
Sobel is not. Also rather expensive, and heavy to hold. The diagrams and
photographs are a delight.

Comparing these two books, then, is like comparing chalk and cheese. They
inhabit different worlds. Readers of this list will enjoy reading the
"Quest", I'm certain. As for the Sobel, I wonder how many share my own
opinion. Perhaps some of you enjoyed it.

==============

There are other works which deal with the question of longitude, or aspects
of it.

I would recommend "Marine Chronometers" by Rupert Gould, the man who
restored the four Harrison instruments. First published in 1923, several
reprints by The Holland Pess, London, to at least 1978.

"Greenwich Time and the Longitude" by Derek Howse, pub. National Maritime
Museum, London, 1997. This has many attractive illustrations, though like
other texts is short on good explanatory diagrams.

There are useful chapters on the subject in "From Sails to Satellites", by
J E D Williams, Oxford, 1992, though it could do with more and better
diagrams.

A pamphlet entitled "Man is not lost" was produced jointly by the National
Maritime Museum and the Royal Greenwich Observatory (HMSO 1968). It
describes rather well the history of the Nautical Almanac and its relevance
to navigation.

For anyone that's looking at a complete history of navigation up to the
invention of the chronometer, "The Haven-finding Art", by E G R Taylor
(Hollis & Carter, London, 1971) provides a satisfying and thorough read,
though the Longitude problem is treated only in the final chapter, and in
words rather than with pictures.

Those that can cope with a mathematical slant could try "A History of
Nautical Astronomy", Charles H Carter, Hollis & Carter, London, 1968. This
goes fully into the complex calculations that the mariner had to deal with
in getting from an observation to a longitude. There were many tricks for
simplifying the working, but even so the problems were formidable. Carter
isn't easy going, but very comprehensive, and knows his trigonometry.
There's stuff here that you are unlikely to find elsewhere.

What books on this topic do other readers recommend?

George Huxtable.



------------------------------

george@huxtable.u-net.com
George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
Tel. 01865 820222 or (int.) +44 1865 820222.
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