down from a computed course of two thousand
■ of water as large as that of the
Missouri itaelf. Hiver after river pour in their floods;
yet however great, tbey appear to produce no effect
oD the main stream. Various causes arc alleged in
explanation of this, besides that of great evaporation.
The whole bed of the Missouri appears to be a loose
shifting sand, through which vast (|uantities of water
are supposed to Alter. Further, it is urged, that
the wide alluvial tracts, io connection with the
river, are based on a porous soil of sand and loam,
which absorbs much of its volume; conveying large
portions into the main valley of the Mississippi by
subterraneous channels. In the same way it may be
argued that the small quantity of water visibly
entering the Gulf by the Mississippi, may be ac-
counted for, by the quantity drawn into that great
general reservoir, by many concealed drains of the
same character.
The upward navigation of the Missouri by ordinary
bouts may be conceived to have always been a most
perilous and arduous task, and even since the intro-
duction of steam-boats, it is found more uncertain
and hazardous than that of any other Western river.
The vast length of its tributaries, and the distance
of its sources, render it liable to frequent floods, of
which three are always confidently looked forward
to at certain intervals in the course of every year.
The first rise that takes place is in the early spring,
when the lower tributaries give forth their surplus



l:



THE MISSOURI.
