Vast echoes resounded in Hilary's mind. "Weather machine--weather machine," he puzzled, holding Joan the tighter. There was more to this than met the eye. He must think. The Viceroy turned suddenly, stared at them, fingering his tube. "I could of course have you killed at once," he thought aloud, "and have no further trouble; but then Urga would be angry." His lidless eyes rested fleetingly on Joan. "And I would lose my public warning to the few Earth dogs who will survive. If it weren't that I needed them to till the fields, and work the machines, I would not leave a single one alive." He seemed to come to a decision. "You'll wait my return." He spoke sharply to the guard. "Bind them up well. Thrust gags into their mouths." He grimaced. "I can taste mine yet. And remember, if they escape, just turn that sun-tube of yours on yourself. It will be pleasanter for you. Understand?" "Yes, Magnificent." The obsequious guard caught hold of Hilary, under the watchful tube of Artok, and proceeded with clumsy weighted fingers to tie him up. Hilary did not resist. An idea was slowly forming in his mind. Joan's turn came next. When they were trussed so tightly that neither could move, the Viceroy smiled mockingly. "We shall meet again, Earth dogs," he said, and was gone. CHAPTER VIII _Rescued_ The guard looked at his captives sourly, kicked viciously at Hilary to relieve his feelings. There was fighting to be had outside; Earth slaves to be tortured and slain, and he was out of it--wet nurse to a couple of prisoners. He growled disconsolately. Through an open slide window giving out on the terrace, a confused roaring, a babel of sounds came filtering through. There was trouble below--fighting already, very likely. The Mercutian glanced back at his bound and gagged prisoners. They were immobile, helpless. He looked guiltily about. The great room was bare, silent. With almost furtive movements he opened the door leading to the terrace, stumbled out, and was leaning over the parapet, absorbed in the spectacle of Great New York below. Instantly, Hilary lifted his head, exerting to the utmost his muscles. He could just see the guard's back, strained over the side. Hilary relaxed rolled painfully over to Joan. She stared at him wide-eyed. If only he could make her understand. He must get the gag out of his mouth. Every moment was precious; the guard might return momentarily. He screwed his face into tremendous contortions, wiggled his feet as much as he could, worked his jaws, trying desperately to convey his meaning. Joan watched him puzzled; trying to follow those strange contortions. Beads of perspiration started on his brow as her face registered blank incomprehension. Just as he was giving up in despair, she grasped the idea. Her face brightened, and her shapely head nodded stiffly.