Immediately the Earthman set himself to the task of examining everything in his prison. But as he had expected, there was little or nothing to discover. The walls which his tether permitted him to reach were all perfectly smooth and solid. He realized with a sheepish grin that it had been foolish of him to even dare to hope that they would be otherwise. The chain fastened to the fetter was quite adequate to hold him. The window, even if it might have been used as an avenue of escape, was securely fastened with bolts, so that it would have taken a man equipped with a heavy set of wrenches, an hour to remove it. To shatter the flexible pane was next to an impossibility. The table was firmly welded to the floor. Beyond the table, Shelby could not go, for the chain prevented him. But he was quite sure that there was nothing movable in the entire room massive enough to be used as a tool or weapon. He slumped down on his bunk, and let one hand rest on a small power-pipe which ran along the wall and up to the illumination globe above. For a minute dejection almost got a firm grip on him. But he fought it off. This was no time to give up. Why, the struggle hadn't even started yet! Shelby felt a faint vibration of the power-pipe under his hand. For a considerable time the impressions had been coming to him, but they had scarcely penetrated into his consciousness. They seemed no more significant than the hundred and one little noises and disturbances that go with the running of any space ship. Presently however, the regular sequence of the pulsations attracted his attention. Something made him think of the almost obsolete Morse code. Then the realization came to him. Someone in another room on he ship was tapping on the power-pipe--signaling--signaling him! He spelled the word out--A-u-s-t-i-n, repeated over and over again. His first thought was of Jan. It must be she who was calling him for there was no one else. Quickly, with his heavy signet ring, he tapped out an answer: "It is I, Jan, A. S. shoot--" With tensed muscles, and with fingers firmly clutching the power-pipe that he might not miss a single signal, Shelby crouched, receiving the message. Somehow there was an urgency, an insistence, an appeal about those hurried pulsations that no human voice could have conveyed. It was fantastically like communicating with one who is buried alive. "We must escape not later than five hours from now," the tapping spelled. "You have been unconscious for a long time--drugged. In five hours we land on Mars. Then escape will be impossible. "Hekki has told me much, and I have seen much. The horrors that are Selba's henchmen--three times some of them came to the ship, once in a band of over a hundred. Hekki is worried. He has not troubled me yet. Too busy I suppose. I have tried to make believe that I agree to his plans. I thought I could control him that way. But he has been taking the Elar drug.