NavList:

   

Reply

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@huxtable.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.
================================================================

   

Reply