The Ringworld Engineers

could do that. “The mountains must have blocked us.”

“And what was it you discussed while we were cut off?”

“Mutiny. We decided against it.”

A momentary pause; then “Very wise,” said the Hindmost. “I want your interpretation of this hologram.”

One of the screens showed a kind of bracket poking out from the rim wall. The picture was slightly blurred, and oddly lit: taken in vacuum, in sunlight and light reflected from the Ringworld landscape on the right. The bracket seemed to be of a piece with the rim wall itself, as if scrith had been stretched like taffy. The bracket held a pair of washers or doughnuts separated by their own diameter. Nothing else showed save the top of the rim wall. It was impossible to guess the scale.

“This was taken from the probe,” the puppeteer said. “I have inserted the probe into the rim transport system, as advised. It is accelerating to antispinward.”

“Yah. What do you think, Chmeee?”

“It might be a Ringworld attitude jet. It would not be firing yet.”

“Maybe. There are a lot of ways to design a Bussard ramjet. Hindmost, do you get anything in the way of magnetic effects?”

“No, Louis, the machine seems dormant.”

“The superconductor plague wouldn’t have touched it in vacuum. It doesn’t look damaged. The controls could be somewhere else, though. On the surface. Maybe they can be repaired.”

“You would have to find them first. In the Repair Center?”

“Yah.”

The road ran between swampland and stony highlands. They passed what looked like another chemical plant. They must have been seen; there was a deep-throated foghorn sound and a blast of steam from what might have been a chimney. Chmeee didn’t slow down.

They saw no more of the boxy vehicles.

Louis had seen pale glimmers passing slowly among the trees, far into the swamp. They moved as slowly as mist on water, or as ocean liners docking. Now, far ahead, a white shape moved free of the trees and toward the road.

From a vast white bulk the beast’s sense-cluster rose on a slender neck. Its jaw was at ground level; it dropped like a shovel blade, scooping up swamp water and vegetation as the beast cruised uphill on rippling belly muscles. It was bigger than the biggest dinosaur.

“Bandersnatch,” Louis said. What were they doing here? Bandersnatchi were native to Jinx. “Slow down, Chmeee, it wants to talk to us.”

“What of it?”

“They’ve got long memories.”

“What would they remember? Swamp dwellers, muck-eaters, without hands to make weapons. No.”

“Why not? Maybe they could tell us what bandersnatchi are doing on the Ringworld in the first place.”

“That is no mystery. The protectors must have stocked their maps in the Great Ocean with samples of the species they considered potentially dangerous.”

Chmeee was playing dominance games, and Louis didn’t like it. “What’s the matter with you? We could at least ask!”

The bandersnatch dwindled behind them. Chmeee snarled, “You avoid confrontation like a Pierson’s puppeteer. Questioning muck-eaters and savages! Killing sunflowers! The Hindmost brought us to this doomed structure against our wills, and you delay our vengeance to kill sunflowers. Will it matter to the Ringworld natives a year from now that Louis the God paused in his passing to pull weeds?”

“I’d save them if I could.”

“We can do nothing. It is the road builders we want. Too primitive to threaten us, advanced enough to know answers to questions. We will find an isolated vehicle and swoop down on it.”

In midafternoon Louis took over the flying.

The swamp became a river that arched away to spinward, wide of its original bed. The crude road followed the new river. The original bed ran more nearly to port, in careful S-curves, with an occasional stretch of rapids or waterfall. It was dry as bone, running into bone-dry desert. The swamp must have been a sea before it silted up.

Louis dithered, then followed the original bed.

“I think we’ve got the timing right,” he told Chmeee. “Prill’s people evolved long after the engineers were gone. Of all the intelligent races here, they were the most ambitious. They built the big, grand cities. Then that odd plague knocked out most of their machinery. Now we’ve got the Machine People, and they could be the same species. The Machine People built the road. They did it after the swamp formed. But I think the swamp formed after Prill’s people’s empire collapsed.

“So what I’m doing is looking for an old Prill People city. We could get lucky and find an old library or a map room.”

They had found cities scarce during the first expedition. Today they traveled for some hours without seeing anything except, twice, a cluster of tents, and once, a sandstorm the size of a continent.

The floating city was still ahead of them, edge on, hiding detail. A score of towers reared around the edge; inverted towers dropped from nearer the center.

The dry river ended in a dry sea. Louis cruised along the shore, twenty miles up. The sea bed was strange. It was quite flat, except where artfully spaced islands with fluted edges rose from the bottom.

Chmeee called, “Louis! Set us on autopilot!”

“What have you found?”

“A dredge.”

Louis joined Chmeee at the telescope.

He had taken it for part of one of the bigger islands. It was huge and flat, disc-shaped, the color of seabottom mud. Its top would have been below sea level. Its seamless rim was angled like the blade of a wood planer. The machine had stalled up against the island it had dredged from the sea bottom.

So this was how the Ringworld engineers had kept the sludge flowing into the spillpipes. It wouldn’t flow of itself; the sea bottoms were too shallow. “The pipe blocked,” Louis speculated. “The dredge kept going till it broke down, or till something cut the power — something like the superconductor plague. Shall I call the Hindmost?”

“Yes. Keep him satisfied… ”

But the Hindmost had bigger news.

“Observe,” he said. He ran a quick succession of holograms on one of the screens. A bracket poked up and out from the rim wall, with a pair of toroids mounted at its tip. Another bracket, seen from farther away; and in this picture a spill mountain showed at the foot of the rim wall. The spill mountain was half the size of the bracket. A third bracket showed. A fourth, with structures next to it. A fifth — “Hold it!” Louis cried. “Go back!”

The fifth bracket stayed on the screen for a moment. Its tip held nothing at all. Then the Hindmost flipped back to the fourth hologram.

It was somewhat blurred by the probe’s velocity. There was heavy lifting machinery anchored to the rim wall next to the bracket: a crude fusion generator; a powered winch; a drum and a hook floating unsupported below it. The cable depending from the drum must be invisibly thin, Louis thought. It could be shadow square wire.

“A repair team already at work? Uurrr. Are they mounting attitude jets or dismounting them? How many are mounted?”

“The probe will tell us,” the Hindmost said. “I direct your attention to another problem. Recall to your mind those toroids that circle the waist of the one intact Ringworld spacecraft. We surmise that they generate the electromagnetic scoop fields for Bussard ramjets.”

Chmeee studied the screen. “The Ringworld ships were all of the same design. I wondered why. You may be right.”

Louis said, “I don’t understand. What has—”

Two one-eyed snakes looked out of a screen at him. “Halrloprillalar’s species built part of a transportation