In obvious response, an Xian colossus of metal dashed forward from a far corner, its gleaming thumbs poised. Rick, dodging to one side, was forced to loosen his hold a little. Fane tore free. Lattimer used the blaster. With a dazing glare its neutron stream cut the legs from the robot. The latter clanked to the floor. "You found a remote control device, Fane," Rick accused. "The war robots are largely automatic, but you are directing them. Why?" Fane made no denial. His face was a grimace of fury. He lunged behind another pillar. "Get him before he really brings hell down on us!" Rick yelled. Lattimer blazed away. Finden, who still had his original blaster, did likewise, discharging the weapon's last energy. Incandescent chunks were torn from the walls and columns. Rick, Finden, and Lattimer ran after Fane but he managed always to keep some obstacle between them and himself. Twice, metal giants lunged at his pursuers and were cut down. One victory the three loyal Survey Service men had. They drove Fane from that hall, with its row of the breech-ends of great tubes. Had he been able to stay a minute longer, calling more ancient battle forces to his aid, they would have been killed without further delay. But there was defeat, too, in his escape from the hall. Considering what forces he must wield outside that was far from good. Rick and his companions chased Fane up a spiral ramp, where the horny tendrils of Martians must once have scurried, and where, at the last, Xians must have fought them. Up and up the spiral went--it was hard to say how far. At last it seemed to be ascending inside a tower, for there were windows glazed with some clear substance. But beyond these panes, and close against them, there was nothing but whiteness. The tower was all but buried. The climb ended in a round chamber fitted with an airlock. But when the men reached the latter, Fane had already passed through it to the outside. Rick rubbed the rime of frozen atmosphere from a window, and they all peered out at a level waste, pale under the stars. Here at the center of the dark hemisphere, the deposit of congealed oxygen and nitrogen and water was so deep that it seemed even to have buried the mountains utterly. Perhaps the tower itself was on a mountain top. Even so, only its cupola projected above the desolation. That and a row of gigantic pipe ends slanting upward from the super-frigid drifts. Their maws yawned black in the still bleakness. For a moment the men almost forgot Fane, as they wondered what it was that they looked upon. "Space ship launching tubes?" Finden suggested. "I'm thinking of something else," Lattimer answered, his voice hollow and awed, yet somehow less tired.