of the river
to the other, that will help the bank tell you when there is water
enough in each of these countless places--like that stump, you know.
When the river first begins to rise, you can run half a dozen of the
deepest of them; when it rises a foot more you can run another dozen;
the next foot will add a couple of dozen, and so on: so you see you have
to know your banks and marks to a dead moral certainty, and never get
them mixed; for when you start through one of those cracks, there's
no backing out again, as there is in the big river; you've got to go
through, or stay there six months if you get caught on a falling river.
There are about fifty of these cracks which you can't run at all except
when the river is brim full and over the banks.'

'This new lesson is a cheerful prospect.'

'Cheerful enough. And mind what I've just told you; when you start into
one of those places you've got to go through. They are too narrow to
turn around in, too crooked to back out of, and the shoal water is
always up at the head; never elsewhere. And the head of them is always
likely to be filling up, little by little, so that the marks you reckon
their depth by, this season, may not answer for next.'

'Learn a new set, then, every year?'

'Exactly. Cramp her up to the bar! What are you standing up through the
middle of the river for?'

The next few months showed me strange things. On the same day that we
held the conversation above narrated, we met a great rise coming down
the river. The whole vast face of the stream was black with drifting
dead logs, broken boughs, and great trees that had caved in and been
washed away. It required the nicest steering to pick one's way through
this rushing raft, even in the day-time, when crossing from point to
point; and at night the difficulty was mightily increased; every now and
then a huge log, lying deep in the water, would suddenly appear right
under our bows, coming head-on; no use to try to avoid it then; we could
only stop the engines, and one wheel would walk over that log from one
end to the other, keeping up a thundering racket and careening the boat
in a way that was very uncomfortable to passengers. Now and then we
would hit one of these sunken logs a rattling bang, dead in the center,
with a full head of steam, and it would stun the boat as if she had hit
a continent. Sometimes this log would lodge, and stay right across
our nose, and back the Mississippi up before it; we