Quade's face twitched perceptibly. His eyes were nervous. "Is that true, Quade?" Holmes asked. There was a steely note in his voice. "Why--no, of course not," the other said hastily, uncertain whether to lie or not. "Of course I didn't!" Phil Holmes looked square into his eyes. He bluffed. "You couldn't desert us, Quade. You haven't the guts. You haven't the guts." His face and eyes burned with the contempt that was in his words. It cut Quade to the raw. But he could not avoid Phil's eyes. He stared at them for a full moment, trembling slightly. Slowly, by inches, he started to back toward the sphere; then suddenly he ran for it with all his might, Holmes after him. Quade got to it first, and inside, as he yanked in the searchlight and slammed and locked the door, he yelled: "You'll see, you damned pup! You'll see!" And there was the smothered sound of half-maniacal laughter.... Phil threw all his weight against the metal door, but it was hopeless and he knew it. He had gathered himself for another rush when he heard Guinness yell: "Back, Phil--back! He'll turn on the side disintegrators!" Mad with rage as the young man was, he at once saw the danger and leaped away--only to almost fall over the professor's prone body. With hurrying, trembling fingers he untied the pair's bonds, and they struggled to their feet, cramped and stiff. Then it was Phil who warned them. "Back as far as you can! Hurry!" He grabbed Sue's hand and plunged toward the uncertain protection of a huge rock far in the rear. At once he made them lie flat on the ground. * * * * * As yet the sphere had not stirred nor emitted a whisper of sound, though they knew the man inside was conning the controls in a fever of haste to leave the cavern. But they hadn't long to wait. There came a sputter, a starting cough from the rocket tubes beneath the sphere. Quickly they warmed into life, and the dully glimmering ball rocked in the hole it lay in. Then a cataract of noise unleashed itself; a devastating thunder roared through the echoing cavern as the rockets burst into full force. A wave of brilliant orange-red splashed out from under the sphere, licked back up its sides, and seemed literally to shove the great ball up towards the hole in the ceiling. Its ascent was very slow. As it gained height it looked--save for its speed--like a fantastic meteor flaming through the night, for the orange plumage that streamed from beneath lit the ball with dazzling color. A glowing sphere, it staggered midway between floor and ceiling, creeping jerkily upwards. "He's not going to hit the hole!" shouted Guinness. The borer had not risen in a perfectly straight line; it jarred against the rim of the hole, and wavered uncertainly. Every second the roar of its rockets, swollen by echoes, rose in a savage crescendo; the faces of the three who watched were painted orange in the glow.