Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    The history of Seafaring.
    From: George Huxtable
    Date: 2007 Dec 7, 18:30 -0000

    It's the time of year when some navigators hint to their wives what they
    might like as a Christmas present. And right on cue, a new book has appeared
    to tempt them. This is "The History of Seafaring", by Donald S Johnson and
    Juha Nurminen, ISBN9781844860401. Cover price in the UK from Conway Books is
    �40, but my copy came from Amazon.uk at �20 post paid. Here's my summary of
    what you get.
    
     First thing you notice is its immense size, nearly 14 inches by 10 inches,
    374 pages of thick paper, weighing over 6 pounds. It classes as a
    "coffee-table" book, simply because it's too big to fit comfortably on your
    knee in an armchair. It's beautifully bound and printed, on high-quality
    paper, to bring out the best in its many pictures. And those pictures are
    the next thing you notice. They are indeed superb! Selected for their visual
    impact, many spreading wall-to-wall across those wide double-pages, they
    really make up a wonderful picture-book. That spread allows the most to be
    got out of its many ancient maps and charts, oil paintings, and some
    beautiful modern pictures too, of the sea and its ships. And those pictures
    are reasonably well captioned. What's more, in general, they are not the
    same old illustrations that get rehashed from one text to another; most of
    them are new, to me at any rate. So, if you want a magnificent artwork about
    the sea and ships, this is for you. From that viewpoint, I have no
    reservations about this book.
    
    But the publishers, on the cover, claim much more. They claim that it
    "pieces together the advances in astronomy, navigation, shipbuilding,
    seamanship, and cartography ..." Note that astronomy and navigation come
    first on that list, and as those topics will interest Navlist readers
    particularly, let's assess the book on that basis. And on that basis, it
    fails, in my view, and fails badly.
    
    I think I can see some reasons why. At the start, there's a page that's
    largely given-over to telling us about the team that put the book together.
    As well as the two authors named above, there are two "other authors". There
    are 5 "editors", of various sorts. There's an "Executive Committee" with 5
    names. There are 5 others, designers, photographers, translators. So this is
    a book that's been written by a committee. And it shows. How it shows!
    
    The book has several different strands. There's a text-strand, presumably
    the work of Johnson, which is hard to follow through the book, as it gets
    broken into, sometimes for several pages at a time, by those pictures, which
    are usually quite irrelevant to the text they interrupt. Next there are
    what's described as "info boxes", also having little connection with the
    main text-strand, which appear to have been written by quite a different
    author or authors, in that there's much duplication of what's already been
    written. These "info boxes" can go on for 2 or 3 pages, often being hard to
    distinguish from the text they break into. Frequently, text gets
    superimposed on the background of a picture, spoiling that picture and
    rendering the text unreadable, to the detriment of both.
    
    There is no cross-referencing, not anywhere. The "info boxes" don't refer to
    the main text, or to the picture. The text-stream doesn't mention the "info
    boxes", or the pictures. The picture captions don't refer to the main text
    or the "info boxes". It's as if these strands had been compiled quite
    separately, perhaps in different continents, so that each creator was quite
    unaware of the context in which his own product would appear. Which makes
    the whole thing completely disjointed. And, to make matters much worse,
    there is NO INDEX of topics! Why ever not, I ask? There's an index of Names,
    only, for what that's worth.
    
    But let's, as I said. look at the astronomy, and the navigation. Perhaps, in
    this sort of work, you wouldn't expect to see much about its mathematical
    basis, and indeed, you don't. Not a single equation, trig expression,
    mathematical symbol: nothing. But wouldn't you expect, at least, a simple
    diagram showing how you can get latitude from an altitude of Polaris or
    midday Sun? Not even that.
    
    Many of the simpler concepts of astronavigation have been misunderstood. I
    will give page numbers in brackets here, in the absence of an index.
    
    (150) "Galileo designed an accessory for the telescope that enabled
    distances to be measured between Jupiter and its moons, thereby determining
    longitude at sea". Jupiter's moons provided time by their disappearance into
    shadow, not by measuring their distance from the planet.
    
    (151) With Zacuto's Sun declination tables "navigators could determine
    latitude from the Sun at any time of the day". How?
    
    (167) The backstaff description would put it upside-down. The nocturnal is
    described as correcting for the "parallax" of Polaris.
    
    (177) The direction of a line trailed astern would provide "course over the
    ground". The effects of ocean currents on navigation could be "estimated by 
    their influence on the height and shape of the ocean waves. Not all 
    navigators possessed this skill ..."
    
    (194) Descibing the nocturnal. "An almanac provided the orientation at
    midnight for every night of the year". No almanac was necessary. A nocturnal
    has its own date-scale, which you set.
    
    (203) Labelling for spring tides diagram is wrong.
    
    (213) "Robert Hooke invented  a method of bringing the object and the
    horizon together into the field of view by using three mirrors". No, just
    one mirror.
    
    (214) "Local time would be established by observing the altitude of the Sun
    at noon". No, well away from noon. "Gemma's method ... remained only a
    theoretical solution for the next 250 years until a portable clock could be
    constructed that would be sufficiently accurate when taken to sea. Only then
    could longitude be determined and the art of navigation finally become a
    science". Thus are lunar distances dismissed. Presumably, he has been
    reading Sobel.
    
    (221) "By not considering the height of the eye above the water, it
    neglected the effect of parallax". Here. dip and parallax are confused.
    
    (292) "The advantage of using the Jovian moons, instead of the Earth's own
    Moon, was their high frequency of occurrence". No, it was because they
    provided an almost-instant moment in time, as they extinguished, without the
    need for precise measurement. "Galileo put forward his idea of using the
    moons of Jupiter to determine longitude, and supplied tables that could
    accurately predict their position". No, there were large errors in any such 
    predictions, ranging over a 15 minute error in time, or more. He refers to 
    Maskelyne's voyage in 1769 to observe the transit of Venus, but that was to 
    the 1761 transit.
    
    (294), referring to Harrison's clocks, "A pair of counter-balancing springs
    made the clock independent of gravity; any change in motion of one spring
    was balanced by the other spring". It did indeed have pairs of springs, but
    that misses the point, which was that it had two counter-rotating balance
    wheels, and THEY made it independent of the ship's motion.
    
    (339) About the binnacle- "Large iron balls placed on either side of the
    compass, a system developed later, took care of compass errors caused by
    non-ferromagnetic influences, such as electrical currents, on the vessel".
    Not at all, those are quadrantal correctors, there to correct for induced
    magnetisation in the iron of the vessel caused by the Earth's magnetic
    field.
    
    (344) Says Ross, in 1839, "sailed to within 200 miles of the geographic
    South Pole before a solid barrier of ice stopped him". Nonsense.
    
    (345) Says that Baffin in 1615 was "the first person to use lunar
    observations at sea to determine longitude". These were done in the ice,
    hardly at sea, and if Baffin had worked his arithmetic correctly those
    observations would have put him some thousands of miles EAST of Greenwich;
    not west of Greenwich as he was!
    
    (335) Confuses the Decca navigation chain with Radar!
    
    These are some basic errors in those aspects of the subject that I know a
    bit about. There are several more, that I haven't listed because they would
    call for somewhat more explanation. It makes me suspect that errors may
    similarly abound in those topics about which I am unfamiliar. There is an
    awful lot in that category, about early voyaging and mapping, which may well
    be of great value, but which I don't know enough about to assess.
    
    =====================
    
    Finally, there are no references to back up any of the statements that are
    made, anywhere. Not a single citation or footnote, in the whole book. There
    is, however, an extensive list, headed "Literature", at the back. It lists
    something like 300 works, some vital to the subject, others, in my view,
    worthless. As I've said, nothing in the text refers to those items. One
    wonders what that immense list is there for. Do the authors claim to have
    read all those, in producing this book? Do they recommend that readers
    should, somehow, look them all up? Or is it simply a list that has been put
    there to impress?
    
    =======================
    
    My summing-up, then is as follows- As a picture-gallery, it is superb. As a
    work about navigational astronomy, it's suspect, misleading, and erroneous.
    And as a work of reference and scholarship- forget it!
    
    But you may like to invest in it just the same. I don't think my �20 has
    been mis-spent.
    
    George.
    
    contact George Huxtable at george---.u-net.com
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site