What did Wilton want? What was he trying to do? As far as could be judged, they had now reached an altitude of 37,000 feet--nearly seven miles. The mists closed in again. The thread of life was on the point of breaking. Linton became half conscious that a thick crust of ice had formed upon his clothes, his breath was freezing on his lips and in his nostrils. He glanced again with an agonizing effort at the moving record of their elevation. Another 1,000 feet, and then 2,000 feet. Needles of ice were pricking at his eyes. Close to him the prone form of Wilton seemed to be covered with minute crystals from head to foot. Linton tried to stretch out his hands to touch him, but found that they were helpless, numbed. What, he vaguely wondered, was Wilton doing now? What mad idea was this? With an exhausting effort the engineer had just smashed the lens of his telescope. Then his hands seemed again to fail him. Watching him helplessly, Linton felt that everything was useless, hopeless, lost. It would soon be over. But Wilton had gripped the broken glass of the telescope between his teeth. What was he doing now? Why was he sawing frantically, convulsively, at that tightened cord? Ah! that was it! Well done, Wilton. But it was hopeless, quite hopeless, after all. Linton rolled his head feebly. They had climbed another 1,000 feet, and they were mounting still. No! What was this? There was a change. Something had happened. Linton was sensible of a strange eddying, a pause, a feebler flapping of the aeroplanes. Merciful God! The boat had ceased to rise. Now she was sinking, sinking, with appalling speed, yet checked to some extent by the broad aeroplanes, just as a bird would be when, with extended wings, it floated down to earth. He tried to frame some words; tried to touch Wilton with his hand; failed to do either. Wilton lay motionless, with bleeding lips. * * * * * Out of the blur of mental chaos, Linton Herrick found himself roughly dragged back to consciousness. Kneeling in the boat, he discovered that he was submerged in water to the waist; flecks of salt water smote him in the face; all around there was a welter of wild, tossing waves. In his ears, to add to his distraction, there sounded a harsh and melancholy bell. It was tolling, tolling, close at hand. The _Bladud_, water-logged, tossed feebly in the trough of the angry sea. Built on a theory that she could float for a considerable period, it nevertheless rushed in upon Linton's mind that in a few minutes she would sink. He struggled to his feet, grasping the rigging as he did so. Something arrested his attention. What was that silent log-like thing the waves were rolling yonder in the semi-darkness? It must be Wilton, poor Wilton, who had saved their lives--or tried to save them, only to lose his own. Wilton! Dead!