Only by a strong exercise of will-power could he hold the biplane to her course. His every instinct was to veer, to retreat back to solid earth, and land somewhere, and once more, at all hazards, get the contact of reality. But Stern resisted all these impulses, and now already had driven the Pauillac right to the lip of the vast nothingness. Now they were over! "My God!" he cried, stunned by the realization of this thing. "Sheer space! No bottom anywhere!" For all at once they had shot, as it were, out into a void which seemed to hold no connection at all with the earth they now were quitting. Stern caught a glimpse of the tall forest growing up to within a hundred yards of the edge, then of smaller trees, dwindling to bushes and grasses, and strange red sand that bordered the gap--sand and rocks, barren as though some up-draft from the void had killed off vegetable growth along the very brink. Then all slid back and away. The red-ribbed wall of the great chasm, shattered and broken as by some inconceivable disaster, some cosmic cataclysm, fell away and away, downward, dimmer and more dim, until it faded gradually into a blue haze, then vanished utterly. And there below lay nothingness--and nothingness stretched out in front to where the sight lost itself in pearly vapors that overdimmed the sky. Beatrice glanced at Stern as the Pauillac sped true as an arrow in its flight, out into this strange and incomprehensible vacuity. Just a shade paler now he seemed. Despite the keen wind, a glister of sweat-drops studded his forehead. His jaw was set, set hard; she could see the powerful maxillary muscles knotted there where the throat-cords met the angle of the bone. And she understood that, for the first time since their tremendous adventure had begun, the man felt shaken by this latest and greatest of all the mysteries they had been called upon to face. Already the verge lay far behind; and now the sense of empty space above and on all sides and there below was overpowering. Stern gasped with a peculiar choking sound. Then all at once, throwing the front steering plane at an angle, he brought the machine about and headed for the distant land. He spoke no word, nor did she; but they both swept the edge of the chasm with anxious eyes, seeking a place to light. It was with tremendous relief that they both saw the solid earth once more below them. And when, five minutes later, having chosen a clear and sand-barren on the verge, some two miles southward along the abyss, Stern brought the machine to earth, they felt a gratitude and a relief not to be voiced in words. "By Jove!" exclaimed the man, lifting Beatrice from the seat, "if that isn't enough to shake a man's nerve and upset all his ideas, geological or otherwise, I'd like to know what is!" "Going to try to cross it?" she asked anxiously; "that is, if there is any other side? I know, of course, that if there is you'll find out, some way or other!"