There was nothing except an immense central shaft, up which ran a hollow pole of glass, cut off by the invisible paint at the summit of the dome. The inside of this glass pole was glowing with colored fires, and it was from this that the intolerable heat came, though its function Dick could not imagine.
One thing was clear: It was growing hotter each moment. To remain in that rotunda meant death within a brief period of time.
_And there was no way out!_ Dick glared around him, searching the glass walls in vain. No semblance of a stairway or ladder, even. Yet the workman must have entered by some ingress--if only Dick could discover it!
He began running round the interior of the dome in the brilliant sunshine, searching frantically for that ingress. And it was growing hotter! The sweat was pouring down his face beneath the invisible garment.
Dick was vaguely aware that the silence switch had been thrown in the room, for his feet made no sound, but the knowledge was latent in his mind. Two or three times he circumnavigated the interior of the dome, like a rat in a trap.
Then suddenly he saw a section of the flooring rise in a corner, and a workman in a blue blouse appear out of the trap door.
He stood there, his face muscles working as he shouted for his companion, but no sound came from his lips. He looked about him, and saw the unconscious man beside the window. He started in his direction.
With a shout, Dick hurled himself toward him. And he checked himself even as he was about to leap. For he realized that the second workman neither saw nor heard him.
Yet some subconscious impression of danger must have reached his mind, for the workman stopped too, instinctively assuming an attitude of defense. Dick gathered a dozen links of his wrist-chain in his right hand, leaped and struck.
The workman crumpled to the floor, a little thread of blood creeping from his right temple.
It was the thing upon which Dick looked back afterward with less satisfaction than any other, leaving the two unconscious men in that room of death. Yet there was nothing else he could have done. He ran to the trap, and saw a ladder leading down. In a moment he had swung himself through and closed the trap behind him.