aching the Rocky mountains, they now changed
their course to the south, and leaving those insulated hills to the
right proceeded across the plain. In this direction captain Lewis had
gone about two miles when his ears were saluted with the agreeable sound
of a fall of water, and as he advanced a spray which seemed driven by
the high southwest wind arose above the plain like a column of smoke and
vanished in an instant. Towards this point he directed his steps, and
the noise increasing as he approached soon became too tremendous to be
mistaken for any thing but the great falls of the Missouri. Having
travelled seven miles after first hearing the sound he reached the falls
about twelve o'clock, the hills as he approached were difficult of
access and two hundred feet high: down these he hurried with impatience
and seating himself on some rocks under the centre of the falls, enjoyed
the sublime spectacle of this stupendous object which has since the
creation had been lavishing its magnificence upon the desert, unknown to
civilization.

[Illustration: The Falls and Portage]

The river immediately at its cascade is three hundred yards wide, and is
pressed in by a perpendicular cliff on the left, which rises to about
one hundred feet and extends up the stream for a mile; on the right the
bluff is also perpendicular for three hundred yards above the falls.
For ninety or a hundred yards from the left cliff, the water falls in
one smooth even sheet, over a precipice of at least eighty feet. The
remaining part of the river precipitates itself with a more rapid
current, but being received as it falls by the irregular and somewhat
projecting rocks below, forms a splendid prospect of perfectly white
foam two hundred yards in length, and eighty in perpendicular elevation.
This spray is dissipated into a thousand shapes, sometimes flying up in
columns of fifteen or twenty feet, which are then oppressed by larger
masses of the white foam, on all which the sun impresses the brightest
colours of the rainbow. As it rises from the fall it beats with fury
against a ledge of rocks which extend across the river at one hundred
and fifty yards from the precipice. From the perpendicular cliff on the
north, to the distance of one hundred and twenty yards, the rocks rise
only a few feet above the water, and when the river is high the stream
finds a channel across them forty yards wide, and near the higher parts
of the ledge which