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    Lewis and Clark Missouri Atlas
    From: George Huxtable
    Date: 2003 Dec 20, 22:54 +0000

    As many members of this list take an interest in the navigation of Lewis
    and Clark, I will, as promised, describe a very recent addition to the
    Lewis and Clark literature.
    
    This is the "Atlas of Lewis and Clark in Missouri" by James D Harlan and
    James M Denny, which has been published in the last month or so, by the
    University of Missouri Press, ISBN 0-8262-1473-8. It costs $60 (maybe less
    from Wal-Mart, I understand).
    
    First thing to say is that it's an impressively handsome volume, in large
    Format at 17 inches wide and 12 high, 180 pages. Finding a suitable
    shelf-space may present a problem.  But this great width pays off, in that
    each map is contained within a single page. It avoids that awful bugbear of
    many atlases, where the spot you want to investigate disappears into the
    cleavage between facing pages.
    
    Print quality is particularly important for any atlas, and is very high in
    this one, on glossy paper. There are several coloured illustrations, taken
    from paintings, which add interest.
    
    But members of this list will mainly be interested in the meat of the
    atlas, its maps showing the length of the river journey through, and
    bordering, the State of Missouri, This was just a part of that great voyage
    Lewis and Clark made, from the Ohio, up the Mississippi to St Louis, then
    up the Missouri, across the divide to the Pacific, returning to St Louis.
    
    I should point out that I'm not a geographer, have never visited Missouri,
    and have never seen any of those great rivers involved in the journey: my
    interest is in the historic navigation. My view of the atlas may be
    somewhat skewed by that viewpoint, which I will assume that Nav-l readers
    share. However, I love maps, and can spend hours reading good mapping.
    
    The really useful part of this atlas, to me, is its collection of maps,
    particularly the 25 maps covering the L&C upstream journey through Missouri
    (1803-4) in great detail, between (modern) Cairo and the Iowa border, South
    of (modern) Omaha, and another 4 maps showing their faster return to St
    Louis in 1806. There are additional maps showing the land-cover of the
    period. There are also many pages of text, a narrative describing the
    journey in some detail. About this text, more later.
    
    The important and valuable new feature of this publication is that Harlan
    and Denny have taken old survey maps of Missouri, made by the General Land
    Office (GLO) between 1815 and 1819 (so in the next decade after L&C),
    assembled that mosaic of survey maps into a whole, and plotted the L&C
    journey as if it had been made on the river that those maps show. It's
    immediatlely clear that the modern river (also indicated on those maps)
    differs significantly, due to changes in its course in the intervening two
    centuries. Doubtless, the 1815-19 survey data provides a much closer fit to
    the river-courses of L&C's passage, though it's likely that some
    significant changes occurred in that interval.
    
    River systems in general (and I know little of the Missouri and middle -
    Mississippi, though presumably they follow a similar pattern) change little
    during a year, except at the times when floods occur, and particularly at
    the infrequent great-floods, when major step-changes can result. The
    possibility has to be kept in mind that such great river-events could well
    have happened in the intervening few years between the journey and the
    survey (and may have been recorded).
    
    Another factor worth considering is that the GLO were making a land survey
    (mainly for the purpose of plot allocation, presumably) and not a river
    survey (for the purposes of navigation). So the rivers are shown as just a
    line indicating where the bank lay, and without any information as to the
    level of the river at that moment, as far as I can tell. No information
    about depths anywhere, nor much in the way of indicating where the main
    channel lay, between the numerous islands. These would, anyway, have been
    rather transient features, in a mobile river-bed. Although the authors use
    the term "historic hydrography", this is hydrography only in a very limited
    sense.
    
    It isn't clear to me, from the text, how precisely the GLO mosaic maps
    could then be (and can now be) correlated with each other and with
    geographical position of lat. and long. (especially long.) Presumably those
    coordinates, if recorded at all, would have been based, at that time, on
    astronomical observations by the surveyors. Precise longitudes were
    unavailable until the telegraph arrived. Presumably, modern coordinates for
    those old maps have now now been obtained by correlating identifiable and
    unchanging features (so, not the river-course) with modern maps on a known
    grid. The authors say something about the processes involved, but don't
    offer any estimates of the size of errors that might result.
    
    Now, for the maps themselves, and particularly the 19 showing the upstream
    passage, each one usually showing about 2 or 3 days of travel.. These are
    on a well-chosen scale of 1:174206, or 2.75 miles to the inch: just right,
    in my view, so show the river details, the islands, tributaries,
    communities, and the detailed (presumed) path of the explorers. They have
    plenty of overlap. Although the maps are printed in colour, all land is in
    grey-green, use of colour being in the river details only.
    
    The valley-bottom, within which the river slowly writhes over the
    centuries, is in a uniform shade, confined between bluffs, beyond which the
    land-relief is shown by shadowing. I must admit to a strong personal
    preference, here, for the precision of contours and altitude-colours,
    though hill-shading may give an instant-impression of how corrugated a land
    may be. However, it's the river that's important, not the land.
    
    Although the maps are all stated to be on a modern projection (Universal
    Transverse Mercator, zone 15), no grid squares are shown, not even any
    marks in the margins, for UTM or lat/long or anything else. There is just
    no way to relate positions in this atlas to positions on any other mapping,
    or (my special interest, and presumably that of other Nav-L members) to
    L&Cs celestial observations. I think this omission may be a serious matter
    for many users. Harlan has kindly supplied me with lat/long positions for
    some camp sites, (from which I can deduce other observation points) and has
    promised to supply the remainder, for which I am grateful. For any further
    edition, I strongly suggest that some grid data should be added, or at
    least coordinates for each corner of each map.
    
    In UTM projection, true North is vertically-upwards near the centre of the
    zone, and deviates from that, for maps East and West of that centre. On
    each page in this atlas a mall North arrow is shown, which the text states
    to show grid North. As the map boundaries are already aligned to grid
    North, that adds little, and I suggest that an indication of True North,
    with its angular offset from the margins, would be much more useful.
    
    The maps shows the presumed position of each overnight camp, at the river
    bank, and a presumed L&C track along the river between them. L&C divided
    each daily distance into a number of legs between what we would now call
    "waypoints", with courses and estimated distances given between the
    waypoints. I have presumed, until now, that those waypoints showed
    turning-points in the river, between straight reaches, at which the course
    changed, and I have also presumed that if those courses and distances were
    added, as a vector-sum, this would provide some sort of dead-reckoning
    assessment of their Northing and Westing, if an inaccurate one, with all
    those twists and turns.
    
    At some of those waypoints, the expedition would certainly pull in to the
    bank to make a noon observation. This atlas, however, takes the view that
    at EVERY such waypoint the craft would pull in to one bank or the other,
    and shows their presumed river-track as doing just that. I doubt if that
    interpretation would be agreed by every L&C investigator.
    
    There are inevitable discrepancies, sometimes major ones, between L&C's
    recorded courses-and-distances, and the "reconstructed" river, if only
    because of river changes in the intervening years. Harlan and Denny seem to
    take the view that when such a discrepancy occurs, it should be resolved by
    abandoning L&C's records in favour of their own river mapping. I'm not
    suggesting that this approach is wrong, because their new mapping is
    presumably better than anyone has seen before, but it may well provoke some
    argument in the L&C community. How did L&C represent their path around a
    bend?
    
    In at least one place, at the Cairo river-junstion, Clark surveyed and drew
    his own sketch-map, which differs significantly from the corresponding map
    in this atlas. Then his first leg to his first waypoint appears to be quite
    incompatible with both his own map and that in the current atlas.
    Incompatible in the sense that neither map shows nearly sufficient width of
    river to accommodate such a course-and-distance as was noted down for that
    leg, if it was indeed intended to represent a crow's flight from A to B. As
    always, when you look into the details, problems arise with L&C.
    
    The text that goes with the maps provides a good account of the journey
    from the explorers' point of view. It follows Gary Moulton's multi-volume
    edition of the journals, but has been completely rewritten into a
    third-person account, in modern language, and in modern spelling and
    punctuation, as opposed to L&C's dreadful manglings of the language. It
    thus becomes a lot more readable than the journals themselves are.
    Something is lost in this process, however, particularly the celestial
    observations and courses and distances, which have all been omitted. Each
    successive edition and rewriting is likely to introduce further errors and
    misunderstandings, and I have come across some errors in those passages
    that deal with the navigational details. For real technical detail, you
    will have to read Moulton, but even he isn't entirely reliable where
    navigation comes in.
    
    In spite of the quibbles I have raised, if you were to ask me whether I was
    satisfied with the atlas I have got for my $60 payment, I would answer-
    "without a doubt, yes."
    
    George Huxtable.
    
    
    
    
    
    
    ================================================================
    contact George Huxtable by email at george---.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
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