Chapter 13 A Pilot's Needs
BUT I am wandering from what I was intending to do, that is, make plainer than perhaps appears in the previous chapters, some of the peculiar requirements of the science of piloting. First of all, there is one faculty which a pilot must incessantly cultivate until he has brought it to absolute perfection. Nothing short of perfection will do. That faculty is memory. He cannot stop with merely thinking a thing is so and so; he must know it; for this is eminently one of the 'exact' sciences. With what scorn a pilot was looked upon, in the old times, if he ever ventured to deal in that feeble phrase 'I think,' instead of the vigorous one 'I know!' One cannot easily realize what a tremendous thing it is to know every trivial detail of twelve hundred miles of river and know it with absolute exactness. If you will take the longest street in New York, and travel up and down it, conning its features patiently until you know every house and window and door and lamp-post and big and little sign by heart, and know them so accurately that you can instantly name the one you are abreast of when you are set down at random in that street in the middle of an inky black night, you will then have a tolerable notion of the amount and the exactness of a pilot's knowledge who carries the Mississippi River in his head. And then if you will go on until you know every street crossing, the character, size, and position of the crossing-stones, and the varying depth of mud in each of those numberless places, you will have some idea of what the pilot must know in order to keep a Mississippi steamer out of trouble. Next, if you will take half of the signs in that long street, and CHANGE THEIR PLACES once a month, and still manage to know their new positions accurately on dark nights, and keep up with these repeated changes without making any mistakes, you will understand what is required of a pilot's peerless memory by the fickle Mississippi.
I think a pilot's memory is about the most wonderful thing in the world. To know the Old and New Testaments by heart, and be able to recite them glibly, forward or backward, or begin at random anywhere in the book and recite both ways and never trip or make a mistake, is no extravagant mass of knowledge, and no marvelous facility, compared to a pilot's massed knowledge of the Mississippi and his marvelous facility in the handling of it. I make this comparison deliberately, and believe I am not expanding the truth when I do it. Many will think my figure too strong, but pilots will not.
And how easily and comfortably the pilot's memory does its work; how placidly effortless is its way; how UNCONSCIOUSLY it lays up its vast stores, hour by hour, day by day, and never loses or mislays a single valuable package of them all! Take an instance. Let a leadsman cry, 'Half twain! half twain! half twain! half twain! half twain!' until it become as monotonous as the ticking of a clock; let conversation be going on all the time, and the pilot be doing his share of the talking, and no longer consciously listening to the leadsman; and in the midst of this endless string of half twains let a single 'quarter twain!' be interjected, without emphasis, and then the half twain cry go on again, just as before: two or three weeks later that pilot can describe with precision the boat's position in the river when that quarter twain was uttered, and give you such a lot of head-marks, stern-marks, and side-marks to guide you, that you ought to be able to take the boat there and put her in that same spot again yourself! The cry of 'quarter twain' did not really take his mind from his talk, but his trained faculties instantly photographed the bearings, noted the change of depth, and laid up the important details for future reference without requiring any assistance from him in the matter. If you were walking and talking with a friend, and another friend at your side kept up a monotonous repetition of the vowel sound A, for a couple of blocks, and then in the midst interjected an R, thus, A, A, A, A, A, R, A, A, A, etc., and gave the R no emphasis, you would not be able to state, two or three weeks afterward, that the R had been put in, nor be able to tell what objects you were passing at the moment it was done.