Continually he was thrown into the rough wall at his right by the centrifugal force of the asteroid. How far did the passageway extend? Was Ku Sui at the end of it? It occurred to the Hawk that the asteroid was a developing shooting star, eating up the few hundred miles of life that remained, streaking down into the atmosphere, where waited quick friction and incandescence--and he down in the heart of it, blind, without clue to what lay in front of him, ignorant of everything, and with only minutes in which to achieve his end. There'd be no heat-warning through his insulated suit. Even now, perhaps, there was no time to get out; already the deadline might have been crossed; he could not know. He went on.... How far? A hundred yards; two hundred? Easily that, he thought, and still no variation in the blackness around him! The passageway seemed straight, so he might now be past the rim of the dome above. Then, for just a second, he saw a faint wisp of light ahead! Automatically Carse's raygun came up, but in the time that simple motion took the light was gone and the blackness was as deep and lifeless as before. But he was coming to something. He went on, perhaps a little faster, hot to discover the last emergency resource of Dr. Ku. He took no pains to avoid making noise, for he knew Ku Sui could not hear him through the airless space between. After another hundred yards or so the light from ahead winked again. It was stronger. Only a second of it, but he now suspected that it came at regular intervals. It was a machine, perhaps, working under the hands of the Eurasian. On--on! With the seconds fleeting by, building to the small total which would bring friction to the asteroid, and incandescence, and scalding death for him within it! Again, suddenly, the mysterious light. It left instantly as usual, but not before it revealed, well ahead, the end of the passage. Quickly he traversed the remaining distance and felt around with his hands. He found what he half expected. There was an opening, a doorway, to his right. The room beyond surely held the final secret of the asteroid. And if Dr. Ku Sui were anywhere, he was in there. * * * * * Carse restrained an impulse to rush in, deciding to wait for the recurring light. Everything in him told him that this was the climax, that through the door to his right lay the object of his chase; and in spite of his consciousness of the plunging asteroid, and the up-leaping skin of Earth's atmosphere, now so close, he stood full in the doorway, gun ready, waiting. Seconds were precious, but this was the part of common sense. He needed the light to show him what perils he must face; he could not go into that chamber ignorant of the situation there.