James Quade laughed. "That's better. You always were essentially reasonable, though somewhat impulsive for a man of your age. The rash way you severed our partnership, for instance.... But enough of that. I think we'd better leave immediately. Into the sphere, please. You first, Miss Guinness." "Must she come?" "I'm afraid so. I can't very well leave her here all unprotected, can I?" Quade's voice was soft and suave, but an undercurrent of sarcasm ran through it. Guinness winced under it; his whole body was trembling with suppressed rage and indignation. As he stepped to the door of the earth-borer he turned and asked: "How did you know our plans? About the radium?--the borer?" Quade told him. "Have you forgotten," he said, "that you talked the matter over with me before we split last year? I simply had the laboratory watched, and when you got new financial backing from young Holmes, and came here. I followed you. Simple, eh?... Well, enough of this. Get inside. You first, Sue." Trembling, the girl obeyed, and when her father hesitated Quade jammed his gun viciously into his ribs and pushed him to the door. "Inside!" he hissed, and reluctantly, hatred in his eyes, the professor stepped into the control compartment after Sue. Quade gave a last quick glance around and, with gun ever wary, passed inside. The door slammed shut: there was a click as its lock shot over. The sphere was a sealed ball of metal. Inside, David Guinness obeyed the automatic's imperious gesture and pulled a shiny-handled lever slowly back, and the hush that rested over the Mojave was shattered by a tremendous bellow, a roar that shook the very earth. It was the disintegrating blast, hurled out of the bottom in many fan-shaped rays. The coarse gray sand beneath the machine stirred and flew wildly; the sphere vibrated madly; and then the thunder lowered in tone to a mighty humming and the earth-borer began to drop. Slowly it fell, at first, then more rapidly. The shiny top came level with the ground: disappeared; and in a moment there was nothing left but a gaping hole where a short while before a round monster of metal had stood. The hole was hot and dark, and from it came a steadily diminishing thunder.... * * * * * For a long time no one in the earth-borer spoke--didn't even try to--for though the thunder of the disintegrators was muted, inside, to a steady drone, conversation was almost impossible. The three were crowded quite close in the spherical inner control compartment. Sue sat on a little collapsible stool by the bowed, but by no means subdued, figure of Professor David Guinness, while Quade sat on the wire guard of the gyroscope, which was in the exact center of the floor.