Finding myself alone, I began to investigate the surroundings with a view of escape. It would have been useless to return as I had come, for even had my chamber door been open, the other end of the passage was closed against me; but the man had fastened the great stone portal after him; it was immovable in its stone socket. I was sealed up alive in a vault whose only opening was far above my head. How to reach that outlet was now what most concerned me. Here I again observed the peculiar odor of those gigantic birds; if it became much stronger I thought it would stifle me. Examining the walls of my prison I found them in many places rough enough to afford a lodgment, huge blocks, projecting into the apartment; but the height was great, and I dared not attempt climbing to the opening above unless sure of finding a passable way to the top. The outlet was not directly in the apex of the roof, but upon one side, near the spring of the arch. The light was dim, and it was some time before I had fully mastered the bearings, but after a careful search I discovered in a remote corner a regular ledge of projecting rock, which appeared to go all the way to the ceiling. Indeed it looked as if it might have been used as a stairway to communicate with the roof. I lost no time in trying this, feeling uncertain as to what fate awaited me. And so, with the little barrel still upon my back, commenced the ascent immediately. As I had thought, it led without difficulty to the aperture, and I begun to congratulate myself with the thought that there was no intention of making me a prisoner after all, when so easy a way had been provided for my escape. But this idea was quickly dispelled on finding myself upon the top of this lofty formation, which fell away upon every side in great chasms, and awful rifts, impossible to cross or descend with any means at my disposal. It was clear enough why there had been no effort to prevent my emerging here. Far out over the desert the atmosphere still quivered in the dreadful heat, but even at this tremendous elevation I could see nothing of the air ship. Was it too small an object to be recognized so far away, or was it hid by the undulations of the sand; or, could it be possible, no, I could not believe it was possible, but still the thought would come to me, that Torrence had repaired the damage, and sailed away alone to continue the exploration by himself? I am sure such a conception would never have entered my mind were it not for the awful strain I had been subjected to.