Mallett gestured swiftly toward those upward-striving masses.
"They can't flow up the cone's steep sides," he said. "Munson knew it when he loosed them on the world. But turning off the condenser now will not destroy those protoplasm masses, nor those over all the world."
"But how——?" Ralton began, to be interrupted by the other.
"Our only chance is to switch the condenser's control," he told him swiftly, "to turn it from the cosmic ray vibration wave-length to the radio-active vibration wave-length. Then instead of attracting and concentrating the cosmic ray vibrations on all earth it would do so with radio-active vibrations and would disintegrate and destroy the protoplasm instantly."
They had turned toward the other window, the one that gave upon the clearing, and gazing through it into the open space they could see that no one moved in it, could hear faintly the voices of Munson and the others, and the occasional tap of tools, from the white-lit laboratory building to the right, which was out of their line of vision. Open and unprotected lay the great condenser at the clearing's center, its vast globe gleaming dully, its glass-faced dials on the black switch-box reflecting the starlight faintly. As they watched, one of those from the laboratory, a dark, intent figure that Ralton recognized as Kingsford, the electrical expert, approached the box, inspected the dials, and then as though satisfied turned back to the laboratory building from which he had come, and from which in another moment they could make out his voice again. Mallett turned swiftly toward his friend.
"They're busy on something," he said, excitedly, "and if ever we're to try for a break now is the time."
Swiftly he produced from his pockets a few odd bits of metal that he had rudely sharpened upon the room's concrete sides, and with these the two began the slow digging and scratching at the cement at the base of one of the bars which was their single chance for freedom. It seemed to Ralton that though they worked madly at the painful task they were making no impression upon the hard cement, in which Mallett had during the past days made some shallow cuts, but still they toiled on at it, hands bruised and bleeding, while the great condenser in the clearing hummed on, and the star-groups above wheeled slowly down toward the west with the near approach of dawn.
In the time that followed, a time that seemed unending to Ralton's dulled senses, they were mocked by the unyieldingness of the cement upon which they worked, and only by continued toil could they make even shallow scratches upon the rough cement. Around the bar's base, silently and unceasingly, though, they worked, hands bloody now, while there came still the occasional murmur of voices from the laboratory building to the right which they could not see. In the clearing the great condenser lay unprotected as ever, but as they worked on it seemed that they were no nearer freedom, and now a gray tinge of light in the dark skies above was bespeaking the coming of dawn. Once, from the window, Ralton glimpsed the gleaming masses at the great cone's base, still surging upward, and saw that they had managed to gain a hold half-way up its steep sides and were vainly and blindly striving to pour still farther upward.
It was not those glistening floods on the barren island below, however, that were central in the thoughts of Mallett and Ralton as they worked on at the bar, bloody and blind with sweat, all but exhausted; it was those other gigantic floods that both knew were even then sweeping over coasts and islands, engulfing the peoples of earth as they rolled on. Neither spoke of that; neither spoke at all as they labored on with all their waning force at the stubborn bar, but the thought was as though visible between them, spurring all their strength into their efforts. And at last, when the dawn-light was strengthening swiftly eastward, they had scratched away the cement from one side of the bar's base, and straightened up, all but exhausted.
"It's all we can do!" panted Mallett. "Our only chance is to get the bar out now—if we wait longer it'll be broad day."