all at home in the dark. Because you know the
shape of it. You can't see it.'

'Do you mean to say that I've got to know all the million trifling
variations of shape in the banks of this interminable river as well as I
know the shape of the front hall at home?'

'On my honor, you've got to know them BETTER than any man ever did know
the shapes of the halls in his own house.'

'I wish I was dead!'

'Now I don't want to discourage you, but--'

'Well, pile it on me; I might as well have it now as another time.'

'You see, this has got to be learned; there isn't any getting around it.
A clear starlight night throws such heavy shadows that if you didn't
know the shape of a shore perfectly you would claw away from every bunch
of timber, because you would take the black shadow of it for a solid
cape; and you see you would be getting scared to death every fifteen
minutes by the watch. You would be fifty yards from shore all the time
when you ought to be within fifty feet of it. You can't see a snag in
one of those shadows, but you know exactly where it is, and the shape of
the river tells you when you are coming to it. Then there's your pitch-
dark night; the river is a very different shape on a pitch-dark night
from what it is on a starlight night. All shores seem to be straight
lines, then, and mighty dim ones, too; and you'd RUN them for straight
lines only you know better. You boldly drive your boat right into what
seems to be a solid, straight wall (you knowing very well that in
reality there is a curve there), and that wall falls back and makes way
for you. Then there's your gray mist. You take a night when there's one
of these grisly, drizzly, gray mists, and then there isn't any
particular shape to a shore. A gray mist would tangle the head of the
oldest man that ever lived. Well, then, different kinds of MOONLIGHT
change the shape of the river in different ways. You see--'

'Oh, don't say any more, please! Have I got to learn the shape of the
river according to all these five hundred thousand different ways? If I
tried to carry all that cargo in my head it would make me stoop-
shouldered.'

'NO! you only learn THE shape of the river, and you learn it with such
absolute certainty that you can always steer by the shape that's IN YOUR
HEAD, and never mind the one that's before your eyes.'

'Very well, I'll try it; but after I have learned it can I depend on it.
Will it keep the same form and not go fooli