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 to it, and the exasperating thing would begin to melt away and fold back into the bank!

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 “thort-ships,”—­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 every one 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 a man the river I mean it. 
    And you can depend on it, I’ll learn him or kill him.”

We have quoted at length from this chapter because it seems of very positive importance here.  It is one of the most luminous in the book so far as the mastery of the science of piloting is concerned, and shows better than could any other combination of words something of what is required of the learner.  It does not cover the whole problem, by any means—­Mark Twain himself could not present that; and even considering his old-time love of the river and the pilot’s trade, it is still incredible that a man of his temperament could have persisted, as he did, against such obstacles.