And the Silver Man settling himself on a ledge above the bath. "Captain Ling, what's going to happen to the rest of your tribe? Just how much rescue are they going to need? Harp tried to tell me a little-"

"Yes. Well, splitting is how integral trees breed." Ling showed no anger at being confronted in his bath. "They fall apart. Now, the half that's falling in, in, it's got only the in tuft, stet? The other end was the midpoint; it's just broken wood. it's got only the in tuft, stet? The other end was the midpoint; it's just broken wood.

"So the wind is blowing just on the in tuft, so it blows the whole tree east, the way the Smoke Ring turns. You push the tree east, it wants a wider orbit. East takes you out. Likewise the other half-tree, which is falling out-" out-"

"So they're both being pushed back to the median."

"Exactly. The wind blows it west, against its motion, so it wants a narrower orbit. Then again, the out half-tree had the rocket motor. It can get back by itself."

"So now you've got two Capability Trees?"

"Maybe. Maybe inhabited by corpses. We'll be very glad of your rescue maneuvers."

A man began scrubbing Aim's upper back; a woman started on his lower back. Then they traded. Body language and blooming romance across AIm's back. It would have been fun without the treefeeding Silver Man. . . who.

He said, "Guardian, thank you for your courtesy to my son." Fair's fair.

Maxell Curtz was glad that he had bathed earlier. Older citizens often said that the Clump had grown crowded; but they never got as close together as this! His inclination was to loll in the foliage somewhere and remember Harp while he listened to Harp's voice. Instead, with Renho and Dunninger, he perched on the rim of the bowl and tried to make conversation.

To Aim Newbry he said, "Not at all. Stevn guided us to where we could do some real good." The so-called Kitemaster was in his thirties, short (but not dwarfed) and muscular, like any climber, but with a kite-man's startling muscular development in his wrists and forearms. Maxell asked, "Your people used to live here?"

"Up to a couple of years ago. A little after we joined the Grove, most of the crops died. We had to move out. Sitzen and Research and Capability Trees gave us seeds, but we still had to get to the Admiralty and buy more. It's the only time any of us have gone to the Admiralty."

"Good thing you were already in reach," Maxell said. Give. Buy. Give. Buy. For sixty people in a tree, it was easy to keep obligations straight. For eleven trees in a Grove, not so easy. A tree might move, or come apart. For two thousand people in a region that changed shape faster than any artist could draw a map . . For sixty people in a tree, it was easy to keep obligations straight. For eleven trees in a Grove, not so easy. A tree might move, or come apart. For two thousand people in a region that changed shape faster than any artist could draw a map . .

Money was less fragile than memory; money lost shape less easily than an obligation.

Admiralty ships had contacted a good many trees over past centuries. Some moved into the East Grove, for access to the Admiralty and the benefits of civilization. Too many did not. For that matter- "How did you get into the Grove, Kitemaster? We looked for a steam rocket."

"Guardian, that's cla.s.sified."

The man was within his rights. Maxell changed the subject. "Captain Ling, we are gathering civilization. Why is it that any tree doesn't come to us right away?"

Harp's music had faded: she was listening.

"Our ships go out through the Smoke Ring to find the places of Man. We talk. We leave word how to find the Admiralty. We leave plans for steam rockets. You need a way to move your tree anyway, anyway, because any pa.s.sage past Gold can hurl you out into the gas torus where you'il suffocate." because any pa.s.sage past Gold can hurl you out into the gas torus where you'il suffocate."

"We built our rocket without help," Ling said. AIm Newbry said nothing.

A tree couldn't just drift drift into the Grove, could it? Sure it could. It wasn't likely, but it could happen . . . and a treeful of climbers might well enjoy bewildering the au-powerful Admiralty. into the Grove, could it? Sure it could. It wasn't likely, but it could happen . . . and a treeful of climbers might well enjoy bewildering the au-powerful Admiralty.

"The Admiralty is the center of knowledge throughout the Smoke Ring. Why would any tribe hesitate?"

Harp was quietly settling between Curtz and Stevn.

Ling said, "I wouldn't want to offend our rescuers."

"I seriously want to know, Captain."

Captain Ling said, "Well, your Admiralty isn't all all good." good."

"How so?"

"The air's thick with garbage."

"There are garbage collectors." collectors."

"They don't collect it all."

Ling had hit a nerve. The garbage probiem had increased with the population, even in Maxell's brief lifespan.

Ling said, "We don't visit the Clump that often, but word does pa.s.s among the trees, Guardian. We're told about the garbage, the crime rate theft. . . violence. . . fringe addiction."

"Don't you have these things in a tree?"

"Not really. We know each other, don't you see? You can't use what you steal. It'll be recognized. If you're a bully, six of us other bullies will give you flying lessons, and if it keeps up, you'll do it without wings. Fringe . . . well, fringe is fun, but it messes up your head. But n.o.body robs somebody for fringe. He finds it on the trunk. If he gets too fond of the stuff, we'll still take care of him. He'll be keeping the cookpot clean instead of hunting."

He was getting reasonable answers. Joy! Maxell asked, "Couldn't you be robbed by another tree?"

"They'd face hunting tools. Knives, harpoons, bows. But your Navy doesn't like it when climbers carry those things in the Clump, so we can be robbed there."

"Rescue?"

Harp spoke just beside him. "We hear stories about that too. We're in debt now, aren't we?"

Again? "Well, yes and no, Harp. The Admiralty thinks that charity works best if it pays for itself."

"If I don't understand that right away, it's because Capability Tree never heard about money until we reached the Grove. So how are we expected to pay?"

"Labor, and there's no hurry. You'll pay some of the debt in mud."

"Mud?"

"You have property rights in the mud that was the core of your tree. That stuff makes fine fertilizer."

Harp laughed.

Dunninger said, "I hauled mud myself before I joined the Navy." Aim Newbry asked, "Can that be done with kites?"

"That's how we did it." Dunninger lifted his arms. "See?"

"Kiteman?"

"Right."

"If Brighton had had money, we could have just bought bought kites from a pa.s.sing citizen. And kite-making instructions. And flying lessons. I don't mind how hard I had to work for my kites," Newbry said, "but what are we missing that we never thought of? We should have gone to the Clump long before. Then again . . . mud. We'd be competing with Admiralty kitemen. And you've been at it a lot longer than we have." kites from a pa.s.sing citizen. And kite-making instructions. And flying lessons. I don't mind how hard I had to work for my kites," Newbry said, "but what are we missing that we never thought of? We should have gone to the Clump long before. Then again . . . mud. We'd be competing with Admiralty kitemen. And you've been at it a lot longer than we have."

"Yup. And we've got ships to haul the bigger blocks. Too bad," said Dunninger.

Renho said, "You're closer, though."

"About ten times closer." Newbry was suffering badly from indecision.

"You could be in there now," Dunninger said. "Can't deal with the Admiralty unless you tree has money. The Vivarium pays money for mud. Half goes to the hauler. And if you're in there pulling mud around, you might run across a last refugee, the one who's injured and can't yell for help."

Curtz was wishing he'd planned this. He thought he knew what would end Newbry's hesitation. "The Admiralty merchants won't even be in the easterly fringes for twenty or thirty days. Take some time to rest, you'd still make it."

"Maybe." Newbry pulled himself out of the water. "Time we were going. Come on, Stevn."

YEAR 419 DAY 121.

Where the lift lines turned at the midpoint, Aim and Stevn let go and kept coasting along the bark. Their kites were furled in their hands.

"You're going," Stevn said.

"I think so. Tow some of the mud from Capability Tree to the Vivarium. You want to come along?"

"Do I have a choice?"

Aim heard bitterness and didn't like it. "This isn't lives at stake, and the other boys have had time to rest. So?"

No answer.

"Bertam and Giliy and Marlow must have had five days' sleep already. I'm dead tired, but I'm the Kitemaster, and h.e.l.l can freeze over before I let the Admiralty take all all our mud. You're dead tired too. So stay in the tuft." our mud. You're dead tired too. So stay in the tuft."

Stevn said, "I was scared all the time."

' 'Ah. ~ "I got the sails set, and I was never sure they were right. At first I was going way way wide of the Navy ship, but I got myself turned, and then I still wasn't sure. How far in can I go before the tree's too far behind me to ever get back? What if the fog thickens up and I get lost? The sky goes on forever. What if the navvies never see me? The Scientist says if I get too far from the air I'll pa.s.s out. Then what?" wide of the Navy ship, but I got myself turned, and then I still wasn't sure. How far in can I go before the tree's too far behind me to ever get back? What if the fog thickens up and I get lost? The sky goes on forever. What if the navvies never see me? The Scientist says if I get too far from the air I'll pa.s.s out. Then what?"

"Yeah."

"I didn't want to say so."

The other pulley was near. Aim s.n.a.t.c.hed at an edge of bark sheet with one hand, got Stevn's ankle with the other, and stopped their flight. "Here's your ride down."

Stevn didn't move.

"I thought I was going to die, my first solo flight," Aim said. "Everything I did took me farther from the tree. A triune family looked me over and never even bothered to separate."

Stevn laughed.

"The only reason I was out there was, I didn't want to be Liftmaster's Apprentice the rest of my life. It looked like Liftmaster Kent was going to live forever. Still does.

"So you go on. Tell the Captain what's going on, and ask him to send the other boys up. Tell your mother I'm going to make Brighton rich-"

"Dad, why don't you tell them yourself?"

"No, I'll stay on the trunk. I need the rest."

"The Silver Man says you've got twenty or thirty days to rest! Talk things over with the Captain. See what we want from the Clump. You might even talk Mom into something."

Stevn's face closed down. He reached for the lift line.

Aim said, "Hold it. I see a lob. Let's geta meal before we go down."

"Where?"

"He's poking an eye over the bark, just there. That must be where his burrow is.. Got your harpoon?"

"Yeah."

"I just don't like arguing," Aim said. "I'd rather fly away, and I d.a.m.n sure know some places n.o.body can follow me. I know I have to talk sometime, but it's . . . it's just . . . But if I can't talk to your mother, mother, my children's my children's mother, mother, then I can't talk to anyone, can I? Even you." then I can't talk to anyone, can I? Even you."

"You're coming down?"

"Yeah. But first I'll show you how to boil a lob in zero tide."

In the aft and side views, all detail had become tiny: integral trees were toothpicks, ponds were drops of glitter, everything seemed embedded in fog. Gold had become a bulge within a larger lens of cloud patterns that trailed off to east and west: a storm pattern that spread across the Smoke Ring. The hidden planet seemed indecently close.

THE INTEGRAL TREES, 1983.

THE ALIEN IN OUR MINDS.

The only universal message in science fiction reads as follows: There are minds that think as well as we do, or better, but differently.

The appropriate questions are, why do you care? Why should they they care? And, where are they? care? And, where are they?

I want to call your attention to humankind's ancient fascination with aliens. There's evolution at work here.

1)Meeting aliens has been a normal thing for humankind. For most of human history, successful tribes have numbered about a hundred. Hunter-gatherer economies need lots of territory, and they have to move frequently.

A hundred thousand years ago, or a million, all humankind was hunter-gatherers. There were strangers around. A wandering tribe might stumble across something different, with odd, ugly faces, bizarre customs, strangely colored skin-and new and useful tools, or new and fearsome weapons.

People who couldn't deal with aliens had to fight when they met. People who could, had their choices. They could trade, they could make agreements including treaties, they could postpone a fight until they had the advantage, they could set rules for war that would allow more survivors. And . . . a man who can talk persuasively to aliens, can also talk persuasively to his own tribe. A persuasive speaker was likely to become the chief.

But even without the external aliens, there were aliens enough.

2)There were wolves. There were horses. There were saber-toothed cats. There were caribou and pigs and rabbits and woolly mammoths.

A recent article in a.n.a.log a.n.a.log pointed out that men are cursorial hunters. pointed out that men are cursorial hunters.

Most predators sprint after their prey. Our ancestors didn't. They picked their target and chased it down over hours or days. A hunter had a better chance of feeding his tribe if he could learn to think like a deer.

So. Somewhere there was a man who found and kept a litter of wolf pups and raised them to know obedience. The tame wolves that didn't learn to think like men didn't live to breed. And somewhere there was a man who leapt on a horse's back and rode it to exhaustion. That tribe had enough to eat, so they didn't eat the horse. Presently they were riding horses.