“Our speed does not seem to be increasing,” I remarked, “as would follow were we approaching the vortex of a true whirlpool.” “I think I can explain it, sir,” said Norton. “It is merely due to the action of the Lunar Eighth Ray which still remains in the forward buoyancy tank. Its natural tendency is to push itself away from the Moon, which, as far as we are concerned, is represented by the rim of this enormous crater. As each portion of the surface repels us in its turn we are pushed gently along in a lessening circle, because, as we drop nearer the summit of the peak the greater the reaction of the Eighth Lunar Ray. If I am not mistaken in my theory our circle will cease to narrow after we have dropped beneath the rim of the crater.” “I guess you are right, Norton,” I said. “At least it is a far more tenable theory than that we are being sucked into the vortex of an enormous whirlpool. There is scarcely enough atmosphere for that, it seems to me.” As we dropped slowly below the rim of the crater the tenability of Norton’s theory became more and more apparent, for presently, though our speed increased slightly, the diameter of our circular course remained constant, and, at a little greater depth, our speed as well. We were descending now at the rate of a little over ten miles an hour, the barometer recording a constantly increasing atmospheric pressure, though nothing approximating that necessary to the support of life upon Earth. The temperature rose slightly, but not alarmingly. From a range of twenty-five or thirty below zero, immediately after we had entered the shadow of the crater’s interior, it rose gradually to zero at a point some one hundred and twenty-five miles below the summit of the giant extinct volcano that had engulfed us. During the next ten miles our speed diminished rapidly, until we suddenly realized that we were no longer falling, but that our motion had been reversed and we were rising. Up we went for approximately eight miles, when suddenly we began to fall again. Again we fell, but this time for only six miles, when our motion was reversed and we rose again a distance of about four miles. This see-sawing was continued until we finally came to rest at about what we estimated was a distance of some one hundred and thirty miles below the summit of the crater. It was quite dark, and we had only our instruments to tell us of what was happening to the ship, the interior of which was, of course, brilliantly illuminated and comfortably warm. Now below us, and now above us, for the ship had rolled completely over each time we had passed the point at which we came finally to rest, we had noted the luminosity that Norton had first observed from above the mouth of the crater. Each of us had been doing considerable thinking, and at last young Norton could contain himself no longer.