ON THE FOURTH PLANET by J. F. BONE Illustrated by FINLAY [Transcriber's Note: This etext was produced from Galaxy Magazine April 1963. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] To Kworn the object was a roadblock, threatening his life. But it was also a high road to a magnificent future! The Ul Kworn paused in his search for food, extended his eye and considered the thing that blocked his path. He hadn't notice the obstacle until he had almost touched it. His attention had been focused upon gleaning every feeder large enough to be edible from the lichens that covered his feeding strip. But the unexpected warmth radiating from the object had startled him. Sundown was at hand. There should be nothing living or non-living that radiated a fraction of the heat that was coming from the gleaming metal wall which lay before him. He expanded his mantle to trap the warmth as he pushed his eye upward to look over the top. It wasn't high, just high enough to be a nuisance. It curved away from him toward the boundaries of his strip, extending completely across the width of his land. A dim racial memory told him that this was an artefact, a product of the days when the Folk had leisure to dream and time to build. It had probably been built by his remote ancestors millennia ago and had just recently been uncovered from its hiding place beneath the sand. These metal objects kept appearing and disappearing as the sands shifted to the force of the wind. He had seen them before, but never a piece so large or so well preserved. It shone as though it had been made yesterday, gleaming with a soft silvery luster against the blue-black darkness of the sky. As his eye cleared the top of the wall, he quivered with shock and astonishment. For it was not a wall as he had thought. Instead, it was the edge of a huge metal disc fifty raads in diameter. And that wasn't all of it. Three thick columns of metal extended upward from the disc, leaning inward as they rose into the sky. High overhead, almost beyond the range of accurate vision, they converged to support an immense cylinder set vertically to the ground. The cylinder was almost as great in diameter as the disc upon which his eye first rested. It loomed overhead, and he had a queasy feeling that it was about to fall and crush him. Strange jointed excresences studded its surface, and in its side, some two-thirds of the way up, two smaller cylinders projected from the bigger one. They were set a little distance apart, divided by a vertical row of four black designs, and pointed straight down his feeding strip.