The Boy Tar

by Mayne Reid

One of these I next folded in triple, and creased for cutting as before. This was a delicate operation, and required all the skill of my fingers to accomplish, for it is much easier to divide a string into two equal parts than into three. I was a good long time before I could get it trebled to my satisfaction; but I succeeded at length, and then severed the parts.

My object in thus cutting into three, was to get the pieces in even fractions of four inches each, in order that by two more doublings I might arrive more accurately at the inch.

And in two more doublings I found it.

To make sure that I had committed no error, I took up the knotted piece, which I had laid aside, and after placing the other fragments where they could be got at, I reduced the second half of the string as I had done the first.

To my gratification, the inch I obtained from both exactly corresponded. There was not a hair’s breadth of difference.

I was now in possession of a guide to the true graduation of my measuring-stick. I had pieces of one foot, of four inches, of two, and of one; and by the help of these I proceeded to mark my rod after the manner of a draper’s yard-stick.

It occupied some time, for I worked with care and caution; but my patience was rewarded by finding myself in possession of a measure upon which I could rely, even in a calculation involving the question of my life.

I was not much longer in deciding the point. The diameters were now measured by feet and inches, and the mean of the two taken. This was reduced to surface measure by the usual method of squaring the circle (multiplying by eight, and dividing by ten). This gave the base of the hollow cylinder, which would be equal to the frustum of a cone of like altitude; and another multiplication by the length produced the entire cubic content.

Dividing by sixty-nine, I got the number of quarts, and so gallons.

The butt, when full, had contained somewhat above 100 gallons—as near as I could calculate, about 108—and therefore it was in all likelihood an old pipe that had once contained sherry.