About six feet from the floor he discovered a sleeping-perch near one end of the apartment. He asked An-Tak about it, but the Galu said that no Weiroo had occupied the place since he had been incarcerated there. Again and again Bradley went over the floor and walls as high up as he could reach. Finally he swung himself to the perch, that he might examine at least one end of the room all the way to the ceiling.

In the center of the wall close to the top, an area about three feet square gave forth a hollow sound when he rapped upon it. Bradley felt over every square inch of that area with the tips of his fingers. Near the top he found a small round hole a trifle larger in diameter than his forefinger, which he immediately stuck into it. The panel, if such it was, seemed about an inch thick, and beyond it his finger encountered nothing. Bradley crooked his finger upon the opposite side of the panel and pulled toward him, steadily but with considerable force. Suddenly the panel flew inward, nearly precipitating the man to the floor. It was hinged at the bottom, and when lowered the outer edge rested upon the perch, making a little platform parallel with the floor of the room.

Beyond the opening was an utterly dark void. The Englishman leaned through it and reached his arm as far as possible into the blackness but touched nothing. Then he fumbled in his haversack for a match, a few of which remained to him. When he struck it, An-Tak gave a cry of terror. Bradley held the light far into the opening before him and in its flickering rays saw the top of a ladder descending into a black abyss below. How far down it extended he could not guess; but that he should soon know definitely he was positive.

"You have found it! You have found the way out!" screamed An-Tak. "Oh, Luata! And now I am too weak to go. Take me with you! Take me with you!"

"Shut up!" admonished Bradley. "You will have the whole flock of birds around our heads in a minute, and neither of us will escape. Be quiet, and I'll go ahead. If I find a way out, I'll come back and help you, if you'll promise not to try to eat me up again."

"I promise," cried An-Tak. "Oh, Luata! How could you blame me? I am half crazed of hunger and long confinement and the horror of the lizards and the rats and the constant waiting for death."

"I know," said Bradley simply. "I'm sorry for you, old top. Keep a stiff upper lip." And he slipped through the opening, found the ladder with his feet, closed the panel behind him, and started downward into the darkness.

Below him rose more and more distinctly the sound of running water. The air felt damp and cool. He could see nothing of his surroundings and felt nothing but the smooth, worn sides and rungs of the ladder down which he felt his way cautiously lest a broken rung or a misstep should hurl him downward.

As he descended thus slowly, the ladder seemed interminable and the pit bottomless, yet he realized when at last he reached the bottom that he could not have descended more than fifty feet. The bottom of the ladder rested on a narrow ledge paved with what felt like large round stones, but what he knew from experience to be human skulls. He could not but marvel as to where so many countless thousands of the things had come from, until he paused to consider that the infancy of Caspak dated doubtlessly back into remote ages, far beyond what the outer world considered the beginning of earthly time. For all these eons the Wieroos might have been collecting human skulls from their enemies and their own dead—enough to have built an entire city of them.

Feeling his way along the narrow ledge, Bradley came presently to a blank wall that stretched out over the water swirling beneath him, as far as he could reach. Stooping, he groped about with one hand, reaching down toward the surface of the water, and discovered that the bottom of the wall arched above the stream. How much space there was between the water and the arch he could not tell, nor how deep the former.