"I scarcely know what I did when I realized that I was hopelessly lost in this pitch black cavern. For one thing, I shouted for help, thinking that possibly Doctor Miranda might hear me. But the echoes from my voice were more terrifying than the silence. The air was stifling; the ground appeared to move beneath my feet; the darkness was like a heavy veil winding closer and closer about me. Then, unable, as it seemed to me, to move or breathe any longer, everything went from me. I sank to the floor unconscious. And that's all I remember." "But--how you say that? You are here, leetle fellow," blurted Miranda. "You are all right." "Yes, I am here," Andrew assented woefully. "But I don't know how I got here. When I came to myself again I was lying on the shore of the lake. It was quite dark. My horse had gone----" "That is right; I take him," corroborated Miranda, with satisfaction. "I don't know how I succeeded in doing it--I suppose it was instinct--but I managed to follow the trail on foot, and after a desperate struggle I reached the village where the people helped me to get back to Bogota." Andrew's story was variously received. No one could doubt his honesty. With such transparent simplicity as his, it would be difficult to suppose him capable of drawing--consciously at least--upon his fancy. Doctor Miranda suggested that he merely dreamed what he afterwards took to be reality. But the others, discrediting this theory, were apparently inclined to accept the story, so far as it went, in spite of its fantastic and well nigh incredible features. Raoul Arthur appeared particularly impressed and proposed immediate action. "I know the cleft in the rock," he said. "I have been over a small part of the passage to which it gives entrance. It was there, three years ago, in our attempt to undermine Lake Guatavita, that a charge of dynamite exploded, after which David Meudon disappeared. I had no idea that this passage extended back into the mountain as far as it does, according to Mr. Parmelee's story. But now--it strikes me, Mr. Leighton, that chance has given us the clew you were seeking last night. If you are still anxious to trace David's whereabouts, the path lies down the passage entered by Mr. Parmelee and his togaed, sandaled guide." "You want to explore it?" demanded Leighton. "I do." "But why, if it was already known to you, have you not done this before?" "The natives have always fought shy of going into it further than our mining operations made necessary. Besides, I never had any reason to suppose that it was more than a mere natural formation of rock--as it probably is--extending a short distance into the main body of the mountain." "And now?" "I have no theory to advance. But," he added significantly, "it was in this unexplored tunnel that David disappeared three years ago."