I now reasoned thus with myself: "If the axis of the earth is hollow,--about which I have no doubt,--and open at both ends,--inasmuch as it is winter at the south pole when it is summer at the north, and _vice versa_,--there must always be a strong current of air passing through it,--the cold air of one extreme rushing into the warmer region at the opposite pole. I have, then, only to find some way of introducing my body into the interior of this axis; and, by taking advantage of the current, I shall soon be able to see daylight again." The next thing, therefore, to be done was to find out whether it would be possible for me to get inside the cylinder. I had observed, that in some places the metal of which it was composed, showed the appearance of being honey-combed; and this gave me some encouragement. I now crawled, or rather swam, about the surface of this cylindrical mass of metal, and soon found an orifice large enough for me to thrust in my hand and arm up to the elbow. True enough, there _was_ a strong draught in there, so strong that it seemed as if my arm would be wrenched from the socket. Every doubt and difficulty were now removed, if I could only find a hole in the cylinder three feet in diameter; and after an hour's search, I lighted upon just what I wanted,--a good smooth opening, and somewhat larger than was actually needed to pass my body through. This, however, was fortunate, because I must have space enough to project myself with some force from the orifice, or I might strike the side of the cylinder, and be dashed into fragments. Every thing was now ready: nerving my whole system for the terrible effort and the frightful risk, I sprang with all my might into the axis of the earth. After what I had experienced when I put my arm into the cylinder, I expected, of course, as soon as my whole body was thrown in there, that I should undergo the terrible sensation of being whirled upward by a tornado. Instead of this, to my astonishment, the moment that I had cleared the orifice through which I jumped I felt as though I were floating stationary in the air. Could it be that I was deceived in regard to the existence of the current? This could hardly be: it was not possible that I was stationary, for the hole through which I leaped had vanished in a flash. It then for the first time occurred to me, that being in the current, and as it were _a part_ of the current, moving in it and _with_ it without any resistance, it was impossible for me to tell whether I was advancing or not; and then I remembered how men that went up in balloons, after they had lost sight of the earth, could not perceive whether they were in motion or at rest; and how our teacher at the Roxbury school used to explain the fact that we were not conscious of the rotation of the globe on which we stood, upon the same principle. When I thought of all this, I broke into a loud laugh, and for a long time I could hear the echoes thundering through the cylinder.