any creature I ever saw before. What did you suppose he
wanted to know for?'

I said I thought it might be a convenience to him.

'Convenience D-nation! Didn't I tell you that a man's got to know the
river in the night the same as he'd know his own front hall?'

'Well, I can follow the front hall in the dark if I know it IS the front
hall; but suppose you set me down in the middle of it in the dark and
not tell me which hall it is; how am I to know?'

'Well you've GOT to, on the river!'

'All right. Then I'm glad I never said anything to Mr. W---- '

'I should say so. Why, he'd have slammed you through the window and
utterly ruined a hundred dollars' worth of window-sash and stuff.'

I was glad this damage had been saved, for it would have made me
unpopular with the owners. They always hated anybody who had the name
of being careless, and injuring things.

I went to work now to learn the shape of the river; and of all the
eluding and ungraspable objects that ever I tried to get mind or hands
on, that was the chief. I would fasten my eyes upon a sharp, wooded
point that projected far into the river some miles ahead of me, and go
to laboriously photographing its shape upon my brain; and just as I was
beginning to succeed to my satisfaction, we would draw up toward it and
the exasperating thing would begin to melt away and fold back into the
bank! If there had been a conspicuous dead tree standing upon the very
point of the cape, I would find that tree inconspicuously merged into
the general forest, and occupying the middle of a straight shore, when I
got abreast of it! No prominent hill would stick to its shape long
enough for me to make up my mind what its form really was, but it was as
dissolving and changeful as if it had been a mountain of butter in the
hottest corner of the tropics. Nothing ever had the same shape when I
was coming downstream that it had borne when I went up. I mentioned
these little difficulties to Mr. Bixby. He said--

'That's the very main virtue of the thing. If the shapes didn't change
every three seconds they wouldn't be of any use. Take this place where
we are now, for instance. As long as that hill over yonder is only one
hill, I can boom right along the way I'm going; but the moment it splits
at the top and forms a V, I know I've got to scratch to starboard in a
hurry, or I'll bang this boat's brains out against a rock; and then the
moment one of the prongs of the V swings b