“What an awful place!” shuddered Ralph, glancing about him nervously. “Yes, let us be pushing on. It is high time we—Great heavens, look here!” The captain had stopped abruptly at the rock on which Jack had dried out his dripping garments. What he had seen had been the ashes of the fire the lad had kindled. “Some one has lit a fire here,” cried Ralph as he, too, saw the embers. “Yes, and not long ago, either.” Captain Atkinson bent over and picked up a handful of the blackened embers, examining them carefully. “This fire is not over forty–eight hours old,” he exclaimed in a voice that fairly shook with suppressed excitement. “And that means that Jack has————” “In some miraculous way been swept over those falls and survived. Let us press on at once. Before dark we may have him with us again.” At these words new life seemed to course through the veins of the two exhausted young Rangers. They plucked up energy and courage from the captain’s manner. “Forward,” cried their leader, plunging into the narrow passage which we have seen Jack traverse. Entering the valley, they had hardly gotten over the first shock of their surprise at its extent and formation when the keen eyes of Captain Atkinson discovered the figure of the Mexican. “What can this mean?” he exclaimed. “Yonder is a man watching us. Let us go up to him at once and find out what this means; perhaps Jack has found friends; perhaps the valley is inhabited.” It was a moment later that the scene of recognition which we have described took place. “How came you here, señors?” demanded the Mexican, who, seemingly, was the first to recover his self–possession. For reply Captain Atkinson whipped out his revolver with incredible swiftness and leveled it at the fellow’s head. “Speak the truth, Alvarez,” he snapped, “or it will be the worse for you. Where is Jack Merrill?” “If you mean the boy who was dashed over the falls with me,” was the reply, “he has gone.” “Gone?” “Si, señor.” “Where?” “Quien sabe.” “Answer me quick, Alvarez.” The brow of Captain Atkinson puckered angrily, his countenance grew dark. “It is as I say, señor. What object would I have in lying to you? The boy climbed yonder cliff but this minute and has vanished.” Although they would have liked to disbelieve the fellow’s story, and incredible as it seemed that a human being could have climbed that cliff, there was an unmistakable ring of sincerity in the man’s tone; it was impossible to make light of his tale. “Boys, we have run against a blank wall,” spoke Captain Atkinson at length, with heavy anxiety in his tone. “Do you think Jack is safe?” breathed Ralph. “Heaven, in whose power he is, alone knows,” was the earnest rejoinder. CHAPTER XVI. LOST IN THE BURNING DESERT.