race, if you will--than a
perfect scholarship in all the dead languages of the world. Greek and
Latin! These have been very barriers to the advancement of knowledge!

Well, I was saying that my old teacher had taught me a few simple
problems in mensuration; and fortunately I still held them in my memory.
I could tell the solid contents of a cube, of a parallelopipedon, of a
pyramid, of a globe (nearly), of a cylinder, and of a cone. The last
was the figure that now interested me.

I knew that a barrel was a pair of cones--that is, truncated cones or
_frustums_--with the bases resting against each other. Of course, when
I was taught how to measure a cone, I was also instructed to do the same
with the frustum of one.

To ascertain the capacity of my butt, therefore, it was only necessary
for me to know its length--or its half-length would do as well--its
circumference at either end, and also its circumference around the
thickest part or "swell." These three measurements given me, I could
tell to a quart how much water would fill it--in other words, I could
calculate how many cubic inches of water it should contain. Knowing
this, I should simply have to divide by 69 and a small fraction over,
and this would give me the number of quarts, which another simple
division of 4 would reduce to gallons, if I required to use this
standard.

I perceived, therefore, that if I could get the three measurements, I
could soon tell the capacity of my butt; but therein lay the difficulty.
How were these measurements to be obtained?

I might have obtained the length, for that was before me from end to
end; but how should I get the circumference either of the middle or of
either end? I could not reach over the top, nor around the ends. Both
directions were blocked up against me.

Another difficulty stared me in the face. I had nothing wherewith to
measure them--neither rule nor tape--no standard by which I could
determine the number of feet or inches; so that even had all sides been
free to me, I should still have been in a dilemma.

I was determined, however, not to yield the point until I had given it a
good thinking. The occupation would help me to pass the time; and, as I
have already hinted, this was a matter of primary importance. Besides,
that faithful old schoolmaster had many a time impressed upon us the
valuable truth, that perseverance often finds success where success
appears impossible. Remembering this bit