He was so tense in the morning that he could scarcely force himself to pretend to work. Lo stayed near him. Fear and hope battled within him. Failure now would mean that Johann Adam would wait in vain, out in the forest, for him to come back. He would know Rog could not help him, at last, and then ... what? He would become older rapidly, for he had many years on his shoulders already. Time would almost surely cut him down before he could find anyone in any of the tribes intelligent enough to know he was not a devil. A cold sweat broke out on his forehead at the thought of so much knowledge being wasted. Though he could not know it, his concern for the secrets of the museum marked him as the first scientist in many thousands of years. When the sun had climbed high over the tops of the leafy trees Rog saw his chance. The others had scattered, paying him little attention. In a flash he had darted to Lo's side and hissed, "Now! We must run fast!" * * * * * They crept to the edge of the clearing and then sprang into the thick, cool darkness of the underbrush. Under the swift feet the miles slipped past. Rog was tense and anxious, Lo eager as a child and a little frightened. She did not know what he did: That upon their reaching the sphere safely depended thousands of years of evolution. And then, almost without warning, they were springing into the small circle of bare ground surrounding the shining ball of metal. They stopped just a few feet away from the closed door and stood hand in hand while Rog shouted. After a moment the bar across the portal began to turn. Then it had swung open ... and in that same instant something took place that drained every drop of blood from Rog's face and left him shivering in dumb despair. Not fifty feet behind them a confused shouting arose, and to their shocked gazes were revealed the running forms of a dozen of the tribesmen, led by Sarak, himself! A groan of despair came from the lips of Johann Adam. Lo sank to the ground and waited for the clubs to end her life with that of Rog. But Rog was too stupefied to do or say anything. His club hung from nerveless fingers. The sight of twelve men rushing upon him seemed not to register in his mind. Then he moved. The club swung up over one shoulder, and he stepped forward one pace. His words carried strongly across the intervening distance. "Wait!" he shouted. "I would do battle with Sarak alone. One so weak and stupid as he has no right to rule!" They stopped. It was a young man's right, if he were so foolish, to challenge the Old Man to battle. It meant that his wisdom and strength were questioned, and only by a battle to the death could it be settled. Sarak roared his acceptance, and the others were bound to wait. He strode from the knot of savage tribesmen, cudgel lofted over his head. Taunts and threats crowded his flabby lips.