On he went to the other opening of the valley, the one which gave upon the territory of the Tatar camp. But he did not sight any of the Mongols as he hacked down a sapling, trimmed, and smoothed it into a blunt-pointed lance. His sash-belt, torn into even strips and knotted together, gave him a rope which he judged would be barely long enough for his purpose. Then Travis made a chancy cast for the lower window of the nearest tower. On the second try the lance slipped in, and he gave a quick jerk, jamming the lance as a bar across the opening. It was a frail ladder but the best he could improvise. He climbed until the sill of the window was within reach and he could pull himself up and over. The sill was a wide one, at least a twenty-four-inch span between the inner and outer surface of the tower. Travis sat there for a minute, reluctant to enter. Near the end of his dangling scarf-rope the two coyotes lay on the pavement, their heads up, their tongues lolling from their mouths, their expressions ones of detached interest. Perhaps it was the width of the outer wall that subdued the amount of light in the room. The chamber was circular, and directly opposite him was a second window, the lowest of the matching diamond pattern. He took the four-foot drop from the sill to the floor but lingered in the light as he surveyed every inch of the room. There were no furnishings at all, but in the very center sank a well of darkness. A smooth pillar, glowing faintly, rose from its core. Travis' adjusting eyes noted how the light came in small ripples--green and purple, over a foundation shade of dark blue. The pillar seemed rooted below and it extended up through a similar opening in the ceiling, providing the only possible exit up or down, save for climbing from window to window outside. Travis moved slowly to the well. Underfoot was a smooth surface overlaid with a velvet carpet of dust which arose in languid puffs as he walked. Here and there he sighted prints in the dust, strange triangular wedges which he thought might possibly have been made by the claws of birds. But there were no other footprints. This tower had been undisturbed for a long, long time. He came to the well and looked down. There was dark there, dark in which the pulsations of light from the pillar shown the stronger. But that glow did not extend beyond the edge of the well through which the thick rod threaded. Even by close examination he could detect no break in the smooth surface of the pillar, nothing remotely resembling hand- or footholds. If it did serve the purpose of a staircase, there were no treads. At last Travis put out his hand to touch the surface of the pillar. And then he jerked back--to no effect. There was no breaking contact between his fingers and an unknown material which had the sleekness of polished metal but--and the thought made him slightly queasy--the warmth and very slight give of flesh!