To you it may seem so, but it did not to me. I had thought of this before. I should not have proceeded as far as I had done—taking so much pains and trouble with the splitting and splicing of my sticks, and making my measurements so exact—had I not foreseen this difficulty, and thought of a way to surmount it. All this had been prospectively arranged. I knew before-hand that I could measure my sticks, and tell their linear dimensions to the exactness of an inch.
“How?”
Thus, then—
When I said just a little ago that I had no standard about my person, I spoke the truth only literally. Although not exactly about my person, I had one in my person—I was myself that standard! You will now remember my having submitted myself to a measurement, which showed me to be four feet in length. Of what value that knowledge now proved to me!
Knowing, then, my own height to be very nearly four feet, I could notch off that measure upon one of the sticks, which would give me a measuring-rule of four feet in length.
I proceeded to obtain this result without delay. The process was simple and easy. Laying myself horizontally, I planted my feet against one of the great ribs of the ship, and rested the end of the stick between them. I now stretched myself out at full length, and guiding the rod so as to keep it parallel to the axis of my body, I brought it across my forehead, and beyond. With my fingers I could tell the point that was opposite the crown of my head, and carefully marking this point, I afterwards notched it with the knife. I now possessed a four-foot rule, exact enough for my purpose.
But there were difficulties yet to be encountered. With a four-foot rule, I was but little advanced towards my computation. I might make a nearer approach to the measurement of my diameters, but that would not avail. I must know them exactly. I must know them in inches, and even fractions of inches; for, as I have said, an error of half an inch in some of my data would make a difference of gallons in the result. How, then, was I to divide a four-foot stick into inches, and register the inches upon its edge? How was this to be done?
It seems simple enough. The half of my four feet—already ascertained—would give me two feet; and the half of that again would reduce the standard to a foot. This again notched in the middle would make two lengths of six inches each. Then I could subdivide those into lengths of three inches, which, if not small enough for my calculation, could be still further subdivided into three equal parts, each of which would be the desired minimum of an inch.
Yes, all this seems easy enough in theory, but how was it to be put in practice upon a piece of plain straight stick, and in the midst of as perfect darkness as that which surrounds a blind man? How was I to find the exact middle—for it must be exact—of even the four feet, much less divide and subdivide till I got down to the inches?
I confess that I was puzzled for awhile, and had to pause and reflect.