After enjoying this rare exercise to our content, we began preparing for the night which was now coming on. The doctor had reminded me of my promise to return to our former position on the moon, and we agreed to set out the next day. Having fastened our car securely to the ground, so that we might not drift off toward the earth, we entered it and made ourselves as comfortable as possible. Our resting place was near the center of what seemed to be an immense crater, and some time before morning we were roused by a violent shaking of the ground beneath us, which startled us beyond expression. “What’s that?” I exclaimed. “That feels very much like a moon-quake,” replied my companion. I was terribly frightened, but resolved to follow the doctor’s example and make light of what we could not help. So I said: “But I thought the lunar volcanoes were all dead ages ago. I hope we haven’t camped in the crater of one that is likely to go off again.” “My opinion is,” answered the doctor, “that there is still water inside the moon which is gradually freezing. That operation would sometimes crack the surface, and this has probably caused the quaking that we have felt.” While we were talking the wind began to blow, and soon, although it was long before time for the sun to rise, we suddenly emerged from darkness into bright sunlight. We sprang up instinctively to look about us and try to discover what this could mean, when what was our consternation to find ourselves adrift! There, in full view of our wondering eyes, was the whole, round earth, hanging in space, and where were we? Then we began to realize gradually that the trembling of the ground was the grating of the moon against the earth as it left its resting place, and the wind was caused by our motion. The novelty of the situation took away for a time the sense of fear, and I exclaimed: “Another scientific certainty gone to smash! I thought you said the moon could never get away from the earth. What are we going to do now?” “Well,” replied the doctor, “this is certainly something I never dreamed of in my philosophy. I didn’t see how the moon could be drawn away from the earth when once actually attached to it, but I suppose the sun and planets all happen to be pulling in one direction just now and are proving too much for the earth’s attraction. But what concerns us more at this time is covered by your question, ‘What are we going to do now?’ And I will answer that I think we will stick to the moon for a while. You can see for yourself that we are held here much more firmly than when we were disporting ourselves in the air yesterday, and the earth is now too far away for us to throw ourselves and our balloon within its attraction.”