The Ringworld Engineers

Louis focused the telescope on the patch of steam. He could see water boiling. Plants would be starting to die. A five-mile strip of plants was getting no sunlight; plants around them were wasting their light on a steam cloud instead of making sugar with it. But a five-mile strip was nothing, nothing. The patch was half the size of a world.

He saw something else that made him swing the view straight upward.

The silver wire was falling, drifting to spinward in the wind. The sunflowers had burned through Sinclair molecule chain. Louis softly spoke a one-syllable word meaning impotence. But the thread of superconductor was still black.

It would hold. Sure it would.

It would be no hotter than boiling water, and everywhere the same temperature. More light from the plants wouldn’t change that; it would only boil the water faster. And this was a big sea. And water vapor doesn’t just vanish. Heat it and it rises.

“God eats well,” the king giant said. He was munching on a head of Boston butter lettuce: his twentieth or maybe thirtieth. He stood beside Chmeee, watching, and like Chmeee he did not speculate on what was happening outside.

Sea water boiled merrily. The sunflowers were sure as tanj determined to knock down that bit of potential fertilizer, that possible sunflower-eating bird. They couldn’t judge altitude or distance. Evolution wouldn’t let them keep that up until they starved. Time off for each blossom to focus on the green photosynthetic node, while others took turns.

Quietly Chmeee said, “Louis. The island.”

Something large and black stood waist-deep in the water offshore. It was not human and not otter, but a little of both. It waited patiently, watching the lander with large brown eyes.

Louis spoke calmly, but with effort. “Is this sea peopled?”

“We did not know it,” said the king giant.

Louis slid the lander toward the beach. The humanoid waited without fear. He was covered with short, oily black fur, and nicely streamlined: thick neck, drastically sloping shoulders, a broad nose flattened against his chinless face.

Louis activated the microphones. “Do you use the speech of the Grass Giants?”

“I can use it. Talk slowly. What are you doing there?”

Louis sighed. “Heating the sea.”

The creature’s self-possession was remarkable. The idea of heating a sea didn’t faze him. He asked the mobile building, “How hot?”

“Very hot at this end. How many are you?”

“Thirty-four of us now,” said the amphibian. “We were eighteen when we came here fifty-one falans past. Will the starboard part of the sea grow hot?”

Louis sagged with relief. He’d had visions of hundreds of thousands of people cooked because Louis Wu had played god. He croaked, “You tell me. The river inlet’s at that end. How much warmth can you stand?”

“Some. We will eat better; fish like warmth. It is polite to ask before you destroy even part of a home. Why are you doing this?”

“To kill off the fire plants.”

The amphibian considered. “Good. If the fire plants die, we can send a messenger upstream to Fuboobish’s Son’s Sea. They must think us long dead.” He added, “I forget my manners. Rishathra is acceptable to us if you will state your sex, and if you can function underwater.”

Louis needed a moment to regain his voice. “None of us mate in water.”

“Few do,” said the amphibian, with no obvious disappointment.

“How did you come here?”

“We were exploring downstream. Rapids carried us into the realm of the fire plants. We could not go ashore, to walk. We must let the river carry us to this place, which I named Tuppugop’s Sea, for myself. It is a good place, though one must be wary of the fire plants. Can you really kill them with fog?”

“I think so.”

“I must move my people,” the amphibian said. He disappeared without a splash.

“I thought you would kill him,” Chmeee told the ceiling, “for his impudence.”

“It’s his home,” said Louis. He turned off the intercom. He was weary of the game. I’m boiling someone’s home, he thought, and I don’t even know it’ll work! He wanted the droud. Nothing else could help, nothing but the vegetable happiness of current running in his brain; nothing else would stop the black rage that had him pounding the arms of his chair and making animal noises with his eyes squeezed tightly shut.

That, and time. Time passed, and the spell passed, and he opened his eyes.

Now he could see neither the black wire nor the boiling of the water. It was all a vast fog bank drifting to spinward, catching fire as it reached shore, ten miles inward and gone. Then only the flare of sunflowers… and a pair of parallel lines at the horizon.

White line above, black below, across fifty degrees of horizon.

Water vapor doesn’t just disappear. Heated, it had gone up, and recondensed in the stratosphere. White edge of cloud, blazing under sunflower attack; black shadow across a tremendous patch of sunflowers. It must be five hundred to a thousand miles away, to be seen so near to its own shadow, and hundreds of miles across. And it was spreading — excruciatingly slowly, but it was spreading.

In the stratosphere the air would be forced outward from the center of the sunflower patch. Some of the cloud would rain out, but some water vapor would meet the steam from the boiling sea and flow inward, recirculating.

His arms hurt. Louis realized that he had a death grip on the chair arms. He let go. He turned on the intercom.

“Louis has kept his promise,” the king giant was saying, “but the dying plants may be out of our reach. I don’t know—”

“We’ll spend the night here,” Louis told them. “In the morning we’ll know better.”

He set the lander on the antispinward side of the island. Seaweed had washed ashore in great heaps. Chmeee and the king giant spent an hour stuffing seaweed into a hatch in the lander’s hull, feeding the converter- kitchen with raw material. Louis took the opportunity to call Hot Needle of Inquiry.

The Hindmost was not on the flight deck. He must be in the hidden part of Needle. “You have broken your droud,” he said.

“I know it. Have you done anything—”

“I have a replacement.”

“I don’t care if you’ve got a dozen. I quit. Do you still want the Ringworld engineers’ transmuter?”

“Of course.”

“Then let’s cooperate a little. The Ringworld control center has to be somewhere. If it’s been built into one of the spill mountains, then the transmuters that came off the ships on the spaceport ledge have to be there. I want to know everything about the situation before I go into it.”

The Hindmost thought it through.

Behind his flat weaving hands, massive buildings glowed with light. A wide street, with stepping discs at intersections, dwindled to a vanishing point. The street swarmed with puppeteers. Their coiffeured manes glowed in glorious variety; they seemed always to move in groups. In a sliver of sky between buildings, two farming worlds hovered, each surrounded by orbiting points of light. There was a background sound like alien music, or like a million puppeteers holding conversations too far away to be heard clearly.

The Hindmost had a piece of his lost civilization here: tapes and a holo wall and, probably, the smell of his own kind constantly in the air. His furniture was all soft curves, with no sharp corners to bump a knee on. An oddly shaped indentation in the floor was probably a bed.

“The back of the rim wall is quite flat,” the Hindmost said abruptly. “My deep-radar won’t penetrate it. I can afford to risk one of my probes. It will still serve as a relay between Needle and the lander; in fact, it will serve better as it rises higher. Accordingly I will place a probe in the rim wall transport