The Ringworld Engineers

Louis crouched behind the front seat while Vala stowed packages through the passenger’s door. Soon they were moving again.

An hour later, far from any habitation, Vala puffed off the road. Louis climbed down from his gu

Vala smiled. “Not till night. But I will drink with you.” She took the colored glass bottle around to the back of the vehicle and ran clear fluid into the nectar. She drank, then passed the bottle. Louis drank.

Alcohol, of course. You couldn’t have oil wells on the Ringworld, could you? But you could build alcohol distilleries anywhere there were plants for fermenting. “Vala, don’t some of the, ah, subject races get to like this stuff too much?”

“Sometimes.”

“What do you do about it?”

The question surprised her. “They learn. Some become useless from drinking. They supervise each other if they must.”

It was the wirehead problem in miniature, with the same solution: time and natural selection. It didn’t seem to bother Vala … and Louis couldn’t afford to let it bother him. He asked, “How far is it to the city?”

“Three or four hours to the air road, but we would be stopped there. Louis, I have given thought to your problem. Why can’t you just fly up?”

“You tell me. I’m for it if nobody shoots at me. What do you think—would somebody shoot at a flying man, or would they let him talk?”

She sipped from the bottle of fuel and nectar. “The rules are strict. None but the City Builder species may come unless invited. But none have flown to the city either!”

She passed him the bottle. The nectar was sweet: like watered grenadine syrup, with a terrific kick from what must be 200 proof alcohol. He set it down and turned his goggles on the city.

It was vertical towers in a lily-pad-shaped clump, in a jarring variety of styles: blocks, needles tapered at top and bottom, translucent slabs, polyhedral cylinders, a slender cone moored tip down. Some buildings were all window; some were all balconies. Gracefully looping bridges or broad, straight ramps linked them at unpredictable levels. Granted that the builders weren’t quite human, Louis still couldn’t believe that anyone would build such a thing on purpose. It was grotesque.

“They must have come from thousands of miles around,” he said. “When the power stopped, there were buildings with independent power supplies. They all got together. Prill’s people mushed them all up into one city. That’s what happened, isn’t it?”

“Nobody knows. But, Louis, you speak as if you watched it happen!”

“You’ve lived with it all your life. You don’t see it the way I do.” He kept looking.

There was a bridge. From a low, windowless building at the top of a nearby hill, it rose in a graceful curve to touch the bottom of a huge fluted pillar. A poured stone road switchbacked uphill to the hilltop building.

“I take it the invited guests have to go through that place at the top, then up the floating bridge.”

“Of course.”

“What happens in there?”

“They are searched for forbidden objects. They are questioned. If the City Builders are choosy about whom they let up, why, so are we! Dissidents have sometimes tried to smuggle bombs up. Mercenaries hired by the City Builders once tried to send them parts to repair their magic water collectors.”

“What?”

Vala smiled. “Some still work. They collect water from the air. Not enough water. We pump water to the city from the river. If we argue over policy, they go thirsty, and we do without the information they gather, until a compromise is reached.”

“Information? What have they got, telescopes?”

“My father told me about it once. They have a room that shows what happens in the world, better than your goggles. After all, Louis, they have height and a view.”

“I should be asking your father all this. How—”

“That may not be a good idea. He is very … he does not see …”

“I’m the wrong shape and color?”

“Yes, he would not believe you can make things like the things you own. He would take them.”

Tanj dammit. “What happens after they let the tourists through?”

“My father comes home with his left arm inscribed in a language only the City Builders know. The script gleams like silver wire. It does not wash off, but it fades in a falan or two.”

That sounded less like a tattoo than like printed circuitry. The City Builders might have more control over their guests than their guests knew. “Okay. What do the guests do up there?”

“They discuss policy. They make gifts: large quantities of food and some tools. The City Builders show them wonders and do rishathra with them.” Vala stood suddenly. “We should be moving.”

They had left the threat of bandits behind. Louis rode in front, beside Vala. Noise was as much a problem as the bumping; they had to raise their voices. Louis shouted, “Rishathra?”

“Not now, I’m driving.” Vala showed a wide expanse of teeth. “The City Builders are very good at rishathra. They can deal with almost any race. It helped them hold their ancient empire. We use rishathra for trading and for not having children until we want to mate and settle down, but the City Builders never give it up.”

“Do you know anyone who could get me invited up as a guest? Say, because of my machines.”

“Only my father. He wouldn’t.”

“Then I’ll have to fly up. Okay, what’s under the city? Can I just stroll underneath and float up?”

“Underneath is the shadow farm. You might pass for a farmer if you leave your tools behind. The farmers are of all races. It is a dirty job. The city sewer outlet is above, and sewage must be spread for the plants. The plants are all cave life, plants that grow in darkness.”

“But … Oh, sure, I see it now. The sun never moves, so it’s always dark under the city. Cave life, huh? Mushrooms?”

She was staring at him. “Louis, how can you expect the sun to move?”

“I forgot where I was.” He grimaced. “Sorry.”

“How can the sun move?”

“Well, of course it’s the planet that moves. Our worlds are spi

The car began to weave. Vala was shaking, her face pale. Gently Louis asked, “Too much strangeness for you?”

“Not that.” She made an odd barking sound. Agonized laughter? “The shadow squares. Obvious to the stupidest of people. The shadow squares mock the day and night cycle for spherical worlds. Louis, I really hoped you were mad. Louis, what can we do?”

He had to give her some kind of answer. He said, “I thought of punching a hole under one of the Great Oceans, just before it reaches the point closest to the sun. Let several Earth-masses of water spew into space. The reaction would push the Ringworld back where it belongs. Hindmost, are you listening?”

The too-perfect contralto said, “It does not seem feasible.”

“Of course it’s not feasible. For one thing, how would we plug the hole afterward? For another, the Ringworld would wobble. A wobble that big would probably kill everything on the Ringworld, and lose the atmosphere too. But I’m trying. Vala, I’m trying.”

She made that odd barking sound and shook her head hard. “At least you do not think too small!”

“What would the Ringworld engineers have done?

“What if some enemy shot away most of the attitude jets? They wouldn’t have built the Ringworld without pla