Despite its size, it was a toy, an absurd and pitiful toy. Real genius and lunacy had many an over-lapping line, Jerry reflected as he approached to look inside. But he found Winslow in a room surrounded by a network of curving, latticed struts. The machine was no makeshift of a demented builder: it was a beautiful bit of construction that Jerry Foster examined. "How did you ever get it here?" he marveled. "What you had in the cave you could pack in, but this--all these parts--castings--cases of supplies--" The inventor did not even turn. He was busy with some final adjustments. "Flew it in," he said shortly. "Built it in an old shop I owned out near Oakland." "And it flew?" Jerry was still incredulous. "Certainly it flew! On a drop or less of the liquids you saw." He pointed to a heavy casting at the center of the machine. There were braces tying it strongly to the entire structure, braces designed to receive and transmit a tremendous thrust. "This is the generator. Blast expelled through the big exhaust at the stern. These smaller exhausts go above and below--right and left at the bow. Perfect control!" "And you flew it here!" Jerry was still trying to grasp that incontrovertible fact. "And you were going to take me to the moon, you said." He looked above him where a pale, silvery segment showed dimly in the sky. "But why the moon?" he questioned. "Even granting that this will fly through space...." "It will," the other interrupted. "I tried it. Went up to better than fifty miles." Jerry Foster took a minute to grasp that statement, then continued: "Granting that, why go to the moon? There is nothing there, no air to speak of, no water! It's all known." * * * * * The inventor turned to face the younger man in the doorway. "There is _nothing_ known," he stated. "The modern telescopes reach out a million light years into space. But the one place they have never seen--can never see--is less than two hundred and fifty thousand miles away. The moon, as of course you know, always keeps the same side toward us. The other side of the moon has never been seen. "Listen," he said, and his deep-set eyes were afire with an intense emotion. "The moon is no tiny satellite; it is a sister planet. It is whirled on the end of a rope (we call it gravitation), swung around and around the earth. How could there be water or anything fluid on this side? It is all thrown to the other side by the centrifugal force. Who knows what life is there? No one--no one! I am going to find out." Jerry Foster was silent. He was thinking hard. He looked about him at the clean hills, the trees, the world he knew. And he was weighing the secure life he knew against a great adventure. He took one long breath of the clear air as one who looks his last at a familiar scene. He exhaled slowly. But he stepped firmly into the machine. "Winslow," he said, "have you any rope handy?"