’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 behind the other, I’ve got to waltz to larboard again, or I’ll have a misunderstanding with a snag that would snatch the keelson out of this steamboat as neatly as if it were a sliver in your hand.  If that hill didn’t change its shape on bad nights there would be an awful steamboat grave-yard around here inside of a year.’

It was plain that I had got to learn the shape of the river in all the different ways that could be thought of,—­upside down, wrong end first, inside out, fore-and-aft, and ’thortships,’—­and then know what to do on gray nights when it hadn’t any shape at all.  So I set about it.  In the course of time I began to get the best of this knotty lesson, and my self-complacency moved to the front once more.  Mr. Bixby was all fixed, and ready to start it to the rear again.  He opened on me after this fashion—­

’How much water did we have in the middle crossing at Hole-in-the-Wall, trip before last?’

I considered this an outrage.  I said—­

’Every trip, down and up, the leadsmen are singing through that tangled place for three-quarters of an hour on a stretch.  How do you reckon I can remember such a mess as that?’

’My boy, you’ve got to remember it.  You’ve got to remember the exact spot and the exact marks the boat lay in when we had the shoalest water, in everyone of the five hundred shoal places between St. Louis and New Orleans; and you mustn’t get the shoal soundings and marks of one trip mixed up with the shoal soundings and marks of another, either, for they’re not often twice alike.  You must keep them separate.’

When I came to myself again, I said—­

’When I get so that I can do that, I’ll be able to raise the dead, and then I won’t have to pilot a steamboat to make a living.  I want to retire from this business.  I want a slush-bucket and a brush; I’m only fit for a roustabout.  I haven’t got brains enough to be a pilot; and if I had I wouldn’t have strength enough to carry them around, unless I went on crutches.’

‘Now drop that!  When I say I’ll learn {footnote [’Teach’ is not in the river vocabulary.]} a man the river, I mean it.  And you can depend on it, I’ll learn him or kill him.’

Chapter 9 Continued Perplexities

There was no use in arguing with a person like this.  I promptly put such a strain on my memory that by and by even the shoal water and the countless crossing-marks began to stay with me.  But the result was just the same.  I never could more than get one knotty thing learned before another presented itself.  Now I had often seen pilots gazing at the water and pretending to read it as if it were a book; but it was a book that told me nothing.  A time came at last, however, when Mr. Bixby seemed to think me far enough advanced to bear a lesson on water-reading.  So he began—­