The trees had utterly vanished, and studding the moss-carpeted plains were only clumps of a willowy shrub from which hung, like grapes, clusters of white waxen blooms. The light too had changed; gone were the dancing, sparkling atoms and the silver had faded to a soft, almost ashen greyness. Ahead of us marched a rampart of coppery cliffs rising, like all these mountainous walls we had seen, into the immensities of haze. Something long drifting in my subconsciousness turned to startled realization. The speed of the shell was slackening! The aperture containing the ionizing mechanism was still open; I glanced within, The whirling ball of fire was not dimmed, but its coruscations, instead of pouring down through the cylinder, swirled and eddied and shot back as though trying to re-enter their source. Rador nodded grimly. "The Shadow takes its toll," he said. We topped a rise--Larry gripped my arm. "Look!" he cried, and pointed. Far, far behind us, so far that the road was but a glistening thread, a score of shining points came speeding. "Lugur and his men," said Rador. "Can't you step on her?" asked Larry. "Step on her?" repeated the green dwarf, puzzled. "Give her more speed; push her," explained O'Keefe. Rador looked about him. The coppery ramparts were close, not more than three or four miles distant; in front of us the plain lifted in a long rolling swell, and up this the _corial_ essayed to go--with a terrifying lessening of speed. Faintly behind us came shootings, and we knew that Lugur drew close. Nor anywhere was there sign of Lakla nor her frogmen. Now we were half-way to the crest; the shell barely crawled and from beneath it came a faint hissing; it quivered, and I knew that its base was no longer held above the glassy surface but rested on it. "One last chance!" exclaimed Rador. He pressed upon the control lever and wrenched it from its socket. Instantly the sparkling ball expanded, whirling with prodigious rapidity and sending a cascade of coruscations into the cylinder. The shell rose; leaped through the air; the dark crystal split into fragments; the fiery ball dulled; died--but upon the impetus of that last thrust we reached the crest. Poised there for a moment, I caught a glimpse of the road dropping down the side of an enormous moss-covered, bowl-shaped valley whose sharply curved sides ended abruptly at the base of the towering barrier. Then down the steep, powerless to guide or to check the shell, we plunged in a meteor rush straight for the annihilating adamantine breasts of the cliffs!