Mankind had worked itself up to the point where it had too much leisure, and turned its energy to the destruction of others. The inevitable result was self-destruction. But the ten he had seen in the pictures stole away and created this museum of history and science, to aid mankind when it must again struggle upward. Under Luk-no's subtle whispering the tribe grew incensed against Rog and watched him constantly, seeking to learn where he went on the days he was absent. They resented the things he "invented" with such regularity. Little did they realize he was but copying things he saw in the sphere. The thing that astounded them most, even Rog himself, was the wheel. He hacked a section of a log into a rough cylinder about three feet thick and bored a hole through it for an axle. Two of these "wheels" he joined together by a peeled pole and made a crude sort of cart, more, perhaps, like a wheelbarrow. But the simple contraption did the work of many men in hauling rocks and meat. Had it not been for the tremendous jealousy it aroused among other young men in the settlement, he would have been acclaimed a hero. Another day he fashioned a device consisting of a bent stick held in a permanent arc by a piece of rawhide. When a notched branch, skinned clean of bark and twigs, was launched by the bowstring, it flew with sufficient force to kill a squirrel. Rog was as delighted as a child with his bow and arrow, and spent many hours practicing with it. There were other things in the museum that brought deep lines to his forehead. He was already beginning to comprehend the principle of the water-wheel and the pulley, but when he saw a man hanging from a great bag high in the air, or a hunter killing a bear by pointing a smoking stick at it, he was stupefied. * * * * * Just six weeks after his discovery of the ball, he found something that froze him with sheer terror, that sent him running away, vowing never to return. On this day he had gone down the stairs through a number of floors, until he came to a room in the very bottom of the sphere. The door to the chamber was closed. It was an unusual door, of a gleaming material that made him blink, and had a single character in the center of it: a red circle from which a small sector had been removed. The sector hovered over the gap, as if asking to be replaced. Rog pushed the door open and went in, suddenly stopped. His face froze, then brightened with eagerness. Hastily he went to the bubble-like dome of glass in the middle of the room. Then he was standing rigid with shock. On a low couch under the glass bell lay an old man clad in flowing, white garments. But he was different from the tribe's old men. He was taller and frailer. His brow was lofty, instead of being crowded down over his eyebrows, and his expression was serene in death.