It was on the fourth day of the experiment. Pale with anxiety and fatigue, Dan still tapped out his messages; still listened at the radio. Suddenly he stood up, with a start. What was that sound he heard? That answering tap, tap, tap? Three shorts and a long--three shorts and a long! In their code, what did that mean? "Where are you? Tell me, where are you?" Or had he counted the signals wrongly. In desperate eagerness, he stood listening. Now there came two longs and a short; then a short and two longs-- "Well, old man, how's the work going?" Dan was so shocked that he leapt back several feet. Not more than a yard away, leering with a horse-like grin, was the face of Wiley! And just in the background, devilishly gaping, were Hogarth and Malvine. Dan's first thought was that the enemy knew what he was about, and had come to mock him at the moment of his seeming success. "Well, how's she going?" Wiley reiterated. "Any progress?" With an effort, Dan snapped out of his stupefied silence. "Oh, she's promising very well," he managed to say. Through the radio, with maddening insistency, came the rat-tat-tat of a message. It was impossible, under the circumstances, to record or translate it! The thought flashed over Dan that he had been tricked; that the message came from the Triumvirs, who were now enjoying his discomfiture! "What's that damned noise?" Hogarth demanded, as if to lend confirmation to this theory. Reaching for a secret switch, Dan snapped off the radio. Only a clever bluff, he knew, could save him now! "Oh, it's only the magnified sound of the impact of the gravitational rays upon the Deflector," he lied, glibly, still hoping against hope. "In other words, the vibrational impetus of--" "To hell with your long-winded explanations!" Wiley cut him short, impatiently. "What we want to know is, what progress have you made? Any sign of getting the earth back in place?" "Time we gave you is about up!" said Malvine. "If you're not getting results, better turn things over to some one else!" "Everything's in the devil's own mess!" sighed Hogarth. "It's hell on earth--people freezing to death right and left. By God! if I thought you weren't getting somewhere, I'd have you choked to death, just for the fun of it!" "Well, as a matter of fact," fabricated Dan, "the Super-Detectonic rays are a bit slow in getting into operation. But you can't expect miracles. If you'll give me a little more time--a few more days, maybe a week--I'll promise you results." A cold sweat had broken out all over him before he had explained, in scientific detail, just why he might succeed if given another week. Thank God! they had not suspected! Or had they suspected?--and were they only toying with him? In any case, they had, wittingly or unwittingly, broken into his experiment at the crucial point. Would he ever again catch the interrupted message?