They swallowed this offering as they would never have his other explanation.
“If you will lead the way,” they said, “we will return. We put our lives in your hands.”
Before going into the cave he paused to take another survey. From his spot in the clearing, which was almost on the top of the hill, he could look over the tree tops and see most of the island, except where other hills barred his view. The island had stopped moving and had settled down against the plain itself. Now, to the untutored eye, the entire mass looked like a clump of dirt, rocks and vegetation for some reason rising from the grassy seas. It would remain so until dusk, when it would again launch itself upon its five-mile-an-hour journey to the east. And once having reached a certain point there, it would reverse itself and begin its nocturnal pilgrimage toward the west. Back and forth, shuttling for how many thousands of years? What was its purpose, and whom had its builders been? Surely they could not have conceived in their wildest dreams of its present use, a mobile fortress for a tribe of cannibals?
Nor could they have seen to what uses their dust-collectors would be put. They couldn’t have guessed that, millennia thence, men ignorant of their originally intended purpose would be using the devices as part of their religious ritual and of human sacrifice.
Green left the others in the room next to the one where the explosion had taken place. They lay down on the hard floor and at once went to sleep. He, however, felt that there were certain things that had to be done and that he was the only one physically capable of doing them.
20
Though he hated to go back into the altar room, he forced himself. The scene of carnage was bad enough, but not as repulsive as he’d expected. Dust had thrown a gray veil of mercy over the bodies. They looked like peaceful gray statues; most of them had not burned on the outside but had died because they’d breathed the first lung-scorching wave of air directly. Nevertheless, despite the look of peace and antiquity, the odor of burned flesh from Aga hung heavy. Lady Luck bristled and arched her back, and for a moment Green thought she was going to leap from his shoulder and run away.
He said, “Take it easy,” then decided that she must have smelled this often before. Her present reaction was based on past episodes; probably, there had been great excitement then. The cats, being taboo animals, must have been figures of some importance in the sacrificial ceremonies.
Cautiously, the man approached the wall of dirt behind the altar, even though he did not think there would be any danger for some time to come. The altar itself was comparatively undamaged. Surprised at this, he ran his hand over it and found out that it was composed of baked clay, hard as rock. The chair and metal rod had not been torn loose. Both were tightly bolted down with huge studs which he supposed had been taken off wrecked ‘rollers.
The victims that were tied in the chair by the savages must have been sitting looking at the audience, so that their backs were to the wall itself. That meant that when the rod was dropped to make contact between the wall and victim, the discharge only burned the sacrifice’s head. Evidence of that was the fact that only skulls were stacked around the altar. The charred head was severed and the body carted outside to one destination or another.
What puzzled Green was how the audience managed to escape the fury of the blast and of the dust, even if they stood at the farthest end of the big room. Determined to find out what happened at those times, he returned to the doorway. Just around its corner, in the second room, he discovered what he’d not noticed before, probably because it was placed so upright and so firmly against one side of the wall. And because its back, which was turned away from the wall, was also made of gray metal. When he switched it around so he could see its other side, he was staring into a mirror about six feet high and four feet wide.
Now he could visualize the ceremony. The victim was strapped into the chair and a rope was tied around the rod. Everybody but the priestess, or whoever conducted the rites, retreated from the altar room. The conductor himself, or herself, then stood in the doorway and released the cord. Before the rod could make contact, the conductor had stepped around the corner. And there the audience saw in the mirror, placed in the doorway so it reflected the interior of the altar room, the ravening discharge of a tremendous electrostatic blast. And immediately afterward, no doubt, they saw nothing because of the dust that would fill the two rooms.
Strange and strong magic to the savages. What myths they must have built about this room, what tales of horrible and powerful gods or demons imprisoned in that wall of dirt! Surely their old women must whisper to the wide-eyed children stories of how the Great Cat-Spirit had been caught by their legendary strong man and savior, some analog to Hercules or Gilgamesh or Thor, and how the Cat-Spirit was the tribe’s to keep prisoner with their magic and to appease from time to time with human kills from other tribes lest it become so angry it burst through the wall of earth and devour everybody upon the floating island!
Green knew that it was hopeless to try to dig through that wall, even if it would be safe for days. It might only be several feet thick, or it might be twenty or more.
But however thick it was, he bet that anybody who had the tools, time and strength to excavate would find, embedded somewhere in that mass, several large dust-collectors. He didn’t know what shape they’d take, because that would depend on the culture that had built them, and their tastes in decorations would differ from Green’s multimillennia-later society. But if they had architectural ideas similar to present-day Terrans they would have constructed the collectors in the shape of busts or of animals’ heads or even of bookcases with false backs of books filling them, books that would in reality have been both chargers and filters. The busts or books would have been pierced with many tiny holes, and through these holes the charged particles of dust would have drifted. Once inside the collectors, they would have been burned.
Looking at the blank dirt before him, Green could see what had happened through the ages. Some part of the burning mechanism had gone wrong—as was the custom of mechanisms everywhere. But the charging effect had continued. And though the dust had piled up around the collectors, the extraordinarily powerful fields had continued to work even through the thick blanket. In the beginning, of course, their field could not have caused any human being harm. But these batteries must have been built to adjust to whatever demand was made of them, though their builders, of course, could have had no idea of how great that demand would some day be. Nevertheless it had come, and the batteries had been equal to it. By the time the savages had found this room they were blocked off by this imposing wall.
Through the death of their fellows they had discovered that touching the wall caused a terrible discharge of electrostatic electricity. The rest of the apparatus for execution and the ritual that went with it was foregone and logical, religiously speaking.
Green swore with frustration. How he would love to get through that dirt before another charge built up! On the other side must be another doorway, and it must lead to the fuel and control rooms for this whole island. If he could get inside and there figure out the controls, he’d turn this island upside down and shake off the man-eating monsters. There’d be no holding him then!
He remembered the story of Samdroo, the Tailor Who Turned Sailor. The legend went that Samdroo, his ‘roller wrecked upon just such a roaming island as this one, had wandered into just such a cave and through rooms like these. But he’d found no barrier of electrically charged dirt and had walked into a room which contained many strange things. One of them was a great eye that allowed Samdroo to see in it what was happening outside the cave. Another was a board which contained many round faces over which raced little squiggles and lines. Of course, the story had its own explanations for what these things were, but Green could hardly fail to recognize TV, oscilloscopes and other instruments.
Unfortunately his knowledge was going to