But he soon raised himself. He had not come down here to be frightened, to let his nerves run away with him. He had come to find out things. What was it that this shell rested upon? Seizing two of the ribs with a strong clutch, he let himself hang over the sides of the shell until his feet were level with its lower side. They touched something hard. He pressed them downward; it was very hard. He raised himself and stood upon the substance which supported the shell. It was as solid as any rock. He looked down and saw his shadow stretching far beneath him. It seemed as if he were standing upon petrified air. He put out one foot and he moved a little, still holding on to the shell. He walked, as if upon solid air, to the foremost end of the long projectile. It relieved him to turn his thoughts from what was around him to this familiar object. He found its conical end shattered and broken. After a little he slowly made his way back to the other end of the shell, and now his eyes became somewhat accustomed to the great radiance about him. He thought he could perceive here and there faint indications of long, nearly horizontal lines--lines of different shades of light. Above him, as if it hung in the air, was the round, dark hole through which he had descended. He rose, took his hands from the shell, and made a few steps. He trod upon a horizontal surface, but in putting one foot forward, he felt a slight incline. It seemed to him that he was about to slip downward! Instantly he retreated to the shell and clutched it in a sudden frenzy of fear. Standing thus, with his eyes still wandering, he heard the bell of the telephone ring. Without hesitation he mounted the shell and got into the car. Bryce was calling him. “Come up,” he said. “You have been down there long enough. No matter what you have found, it is time for you to come up.” Roland Clewe was not accustomed to receive commands, but he instantly closed the sliding door of the car, seated himself, and put his mouth to the telephone. “All right,” he said. “You can haul me up, but go very slowly at first.” The car rose. When it reached the orifice in the top of the cave of light, Clewe heard the conical steel top grate slightly as it touched its edge, for it was still swinging a little from the motion given to it by his entrance; but it soon hung perfectly vertical and went silently up the shaft. CHAPTER XXII. CLEWE'S THEORY Seated in the car, which was steadily ascending the great shaft, Roland Clewe took no notice of anything about him. He did not look at the brilliantly lighted interior of the shaft, he paid no attention to his instruments, he did not consult his watch, nor glance at the dial which indicated the distance he had travelled. Several times the telephone bell rang, and Bryce inquired how he was getting along; but these questions he answered as briefly as possible, and sat looking down at his knees and seeing nothing.