At dawn I got up and went to look for the ponies. I climbed one of the low dunes and gazed over the gray infinity of sand, but not a sign of them rewarded my look. I tried to trail them. I found where they had been hobbled, and followed the tracks of each to a place where the hoofs had cut deep in the sandy turf. Beyond there was no trace. Then I was certain of what I had already known, that the Thing had carried them away. Then I found something stranger still--the prints of bare human feet, half erased by the wind that had blown while the terror had hung there. That unearthly laugh, and the footprints! Was there a land of madmen behind the mountain? And what was the thing that had come and gone in the night? Those were questions I could not answer, but daylight dulled my wondering fear. The sun would not rise on my side of the mountain until nearly noon, and the cold dark shadow of the cliff was upon me when the desert all about was a shimmering white in the heat of the sun. Austen's call had mentioned a ladder. I set out to find it. Just north of the peak I came upon it, running straight up like a silver ribbon to the top of the cliff. It was not the clumsy affair of ropes that I expected. In fact, I at once abandoned any idea that Austen had made it at all. It was of an odd-looking white metal, and it seemed very old, although it was corroded but little. The rungs were short white bars, riveted to long straps which were fastened on the rock by spikes of the same silvery metal. I have said that the mountain rises straight from the sand. And the ladder goes on into the ground. That suggests that the sand has piled in on the base of the mountain since the ladder was put there. At any rate, I am sure that it is incredibly old. I went back to camp; packed together my guns, a little food, and Austen's equipment; and started up the ladder. Although it was no more than six hundred feet to the top, heavily laden as I was, I got very tired before I reached it. I stopped several times to rest. Once, looking down on the illimitable sea of rolling sand, with the tiny tent and the sharp shadow of the mountain the only definite features, I had a terrible attack of vertigo, and my fears of the night returned, until I almost wished I had never started up the ladder. But I knew that if I were suddenly back in Perth again I would be more eager than ever to set out upon the adventure. At last I reached the top and crawled up in the mouth of a narrow canyon, with the black stone walls rising straight to the peaks on either side. Down the crevice was a smooth curving pathway, very much worn, it seemed, more by time than human feet. It was not yet noon. I waited a few minutes to rest; then walked up the path with a very keen curiosity as to where it led. It grew so deep that the sky overhead was but a dark blue ribbon in which I saw Venus gleaming whitely. It widened. I walked out on a broad stone platform. And below me lay--the abyss.