"I am as anxious as you." Anthony's slow words were dubious. "But it may still be dangerous. The gas may have cleared away only from our immediate vicinity. In hollows, or places where the air is stagnant, it may still be toxic. It is my opinion that only one should go at first, to investigate." A babble of volunteering cries burst out, but Dane's voice cut through the others. "Look here," the sentence tumbled from his lips. "I'm an extra here. It doesn't matter whether I live or die--I have no special knowledge. I cannot even father a family, since I have no wife. I am the only one to go out as long as there is danger." "The young man is right," some one said. "He is the logical choice." "Very well," agreed Anthony, who appeared the leader. "He shall be the first." * * * * * His instructions were few. One plane had been preserved, and was in the shaft. Allan was to make a circuit of the neighborhood. If he deemed it safe he was to visit the building, described to him, where the fourth couple had lived, and see if he could find trace of them. Then he was to return and report his findings. All stuffed their ears with cotton wool, and crowded against one end of the chamber. Anthony had the end of a long double wire in his hand, and it curled across the floor to the farther wall. He pressed the button of a pear-switch--and there was a concussion that hurled the watchers against the wall behind them. A great gap appeared in the farther wall, beyond it a black chasm, and a helicopter that was dimly illumined by the light from within the room. A quick inspection of the flier revealed that its alumino-steeloid had been unaffected by the passage of time, and Allan climbed into it. A wave of his hand simulated an insouciance he did not feel. Then he was rising through darkness. The sun's light struck down and enveloped him, and he was in the open air. He rose above the trees. Desolation spread out beneath him. In all the vastness that unfolded as the lone 'copter climbed into a clear sky, nothing moved. The air, that from babyhood Allan had seen crowded with bustling traffic, was a ghastly emptiness. Not even a tiny, wheeling speck betrayed the presence of a bird. And below--the gas that was fatal to animal life seemed to have stimulated vegetable growth--an illimitable sea of green rolled untenanted to where the first ramparts of New York rose against the sky. Roads, monorail lines, all the countless tracks of civilization had disappeared beneath the green tide. Nature had taken back its own.