The hidden room was cool, but Garry Connell wiped the sweat from his eyes when he ceased his frantic efforts. The metal bar clanged loudly upon the floor beside him. He stood, breathing heavily, his eyes on the metal cover that refused to move. And in the silence there came to him again that strange, prickling apprehension. He caught himself looking quickly behind him as if to find another person there. His eyes were accustomed now to the pale light, and the sculptured figures on the walls stood out with startling distinctness. Garry turned to look at the nearer wall and the figure that was repeated over and over again. It was a man, tall and lean, his robes, undimmed by the years, blazed in crimson and gold. But the face above! Garry shivered in spite of himself at the devilish ugliness the artist had copied. It was dead black in color, with slitted eyes that had been touched up artfully to bring out their venomous stare. The head itself rose up to a rounded point that added to the inhuman brutality of the face. He was seated on a throne, Garry saw, and other figures, less skilfully carved, were kneeling before him. Again, he was standing above a prostrate enemy, a triple-pointed spear raised to deliver the final blow. Silently, Garry let his eyes follow around the room with its repetition of the horrible being who was evidently a king. Then he whistled softly. "Nice kind of hombre, he must have been," he said. And, "Boy," he told the carved image familiarly, "whoever you were, you've been dead a long time, and I don't mind telling you I'm glad of it." He was slowly circling the first casket. Beyond it was the slender rod with its mushroom head that seemed more like a bell as he looked from below. The head's inner surface was emblazoned, like the figures on the wall, with crimson and gold in strange designs. He saw now that the base of it was connected with a smaller box, placed like the two beside it on a stone pedestal. He came slowly beside it to study the box with narrowed eyes. He expected the metal cover would be as immovable as the others, and he started back and caught his breath sharply as the metal raised at his touch and the green radiance from above flashed back from within the box in a thousand scintillant lights. Then he stooped to see the brilliant, silvery sheen of metal wheels that moved on jeweled bearings. * * * * * A mechanism of some sort--but what? he wondered. He had some knowledge of the stream of electrons that discharged continuously from the light above, and he knew how they could charge an electroscope that would automatically discharge to produce motion. He nodded in half-understanding as the fluttering gold-leaf fell and allowed a tiny wheel to move one notch in its escapement. "Clockworks!" he told himself--it was as near as he could come to a name for the machine--"and it's been running here all this time.... What for, I wonder? What was it supposed to do?"