The Mississippi is notable for its varying length. Within the memory
of the oldest pilot the length of the river between St. Louis and New
Orleans has varied more than one hundred and fifty miles, being
sometimes longer and sometimes shorter, as the year may be one of
drought or of excessive rainfall. Occasionally the river will shorten
itself a score of miles at a single leap. The shortening invariably
takes place at one of its long sinuous curves for which it is so
remarkable. At a season when the volume of water begins to increase,
the narrow neck of the loop gives way little by little under the
continuous impact of the strengthening current. Narrower and narrower
it grows as the water ceaselessly cuts away the bank. Finally the
barrier is broken; there is a tumultuous meeting of waters; the next
steamboat that comes along goes through a new cut; and a moat or
ox-bow lake is the only reminder of the former channel.[5]
[Footnote 5: One of the most noteworthy examples of these cut-offs is
Davis'. This cut-off occurred at Palmyra Bend, eighteen miles below
Vicksburg. The mid-channel distance around the bend was not far from
twenty miles; the neck was only twelve hundred feet across. The fall
of the river, measured around the bend, was about four inches per
mile; the slope, measured across the neck, was about five and one-half
feet, nearly twenty feet per mile.
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