"Well," suddenly laughed Stern, with a strange accent in his voice, "well then, here goes for the operator in the Eiffel Tower, eh?"
Again he glanced keenly, in the failing light, at the apparatus there before him.
"She'll do, I guess," judged he, slipping on the rusted head-receiver. He laid his hand upon the key and tried a few tentative dots and dashes.
Breathless, the girl watched, daring no longer to question him. In the dielectric, the green sparks and spurts of living flame began to crackle and to hiss like living spirits of an unknown power.
Stern, feeling again harnessed to his touch the life-force of the world that once had been, exulted with a wild emotion. Yet, science-worshiper that he was, something of reverent awe tinged the keen triumph. A strange gleam dwelt within his eyes; and through his lips the breath came quick as he flung his very being into this supreme experiment.
He reached for the ondometer. Carefully, slowly, he "tuned up" the wave-lengths; up, up to five thousand metres, then back again; he ran the whole gamut of the wireless scale.
Out, ever out into the thickening gloom, across the void and vacancy of the dead world, he flung his lightnings in a wild appeal. His face grew hard and eager.
"Anything? Any answer?" asked Beatrice, laying a hand upon his shoulder--a hand that trembled.
He shook his head in negation. Again he switched the roaring current on; again he hurled out into ether his cry of warning and distress, of hope, of invitation--the last lone call of man to man--of the last New Yorker to any other human being who, by the merest chance, might possibly hear him in the wreck of other cities, other lands. "S. O. S.!" crackled the green flame. "S. O. S.! S. O. S.!--"
Thus came night, fully, as they waited, as they called and listened; as, together there in that tiny structure on the roof of the tremendous ruin, they swept the heavens and the earth with their wild call--in vain.
Half an hour passed and still the engineer, grim as death, whirled the chained lightnings out and away.
"Nothing yet?" cried Beatrice at last, unable to keep silence any longer. "Are you quite sure you can't--"
The question was not finished.
For suddenly, far down below them, as though buried in the entrails of the earth, shuddered a stifled, booming roar.
Through every rotten beam and fiber the vast wreck of the building vibrated. Some wall or other, somewhere, crumbled and went crashing down with a long, deep droning thunder that ended in a sliding diminuendo of noise.