“You do look a little beat. But then so am I. Trying to make sense of Wohler-9 is exhausting, and so far he's the best of the Averies. I learned very little today. We could both do with early tether. I'll see you in the morning, Sarco.”

“Wait up! You're not getting off that easy.”

But Synapo had already balled and was dropping, if not like a rock, still at an appreciable rate that put him out of earshot in a trice. Sarco sighed-a soft gentle emission of pure oxygen with a faint trace of unreacted ammonia-but did not follow immediately.

As Synapo approached the surface of the planet, he began braking, unfurling from his collar the tough filmy hide of his reflector, letting it flap and rattle in his wake as it dragged at him like a sea anchor. As he neared the trees on the side of the domed transparency away from the open sector, he sealed the gores of the thin, shiny reflector, sealing all but his head inside, leaving his hook and eyes protruding from the underside.

With gentle bursts of compressed hydrogen, he began to inflate the reflector, dissipating his momentum and slowing his descent until he was barely drifting downward. Ten meters above the top of a tall conifer, he let go his chitinous hook, letting out the tether of tough, stringy hide until the hook was dangling below a sturdy limb. A final burst of hydrogen filled the reflector, erasing the last crease to leave a smooth, unblemished, mirrorlike surface. The tether twanged taut, caught between the now buoyant silvery balloon and the hooked limb of the tree.

Synapo began the luxurious process of uncoiling his tense fibers, drifting into deep tether as he lay suspended within his own skin. His storage cells were not sated with a day's thermoelectric output from the sun's radiant heat as they normally would have been if the aliens had not been disturbing the atmosphere; but little of the radiation he had been exposed to that day had escaped the nearly perfect blackbody absorption of his other skin. That energy was all there, save only the small expenditure for intense thought and languid motion, and the large expenditure for electrolyzing water and compressing hydrogen; and the unusual expenditure that day to converse-if it could be called that-with Wohler-9. Still, he had a sufficient reserve of juice left in his cells. It would take little to get him through the night, just that amount needed to maintain body temperature, to make up for the minuscule amount of energy lost by radiation from his silvery hide.

Sarco stayed aloft until Synapo tethered. Then he balled and dropped and tethered nearby so as to confront Synapo the next morning, first thing.

The Avery robots continued to stream from the open sector of the dome like ants abandoning an anthill. Dusk was coming on rapidly, but night would not hamper their operations.

Wohler-9 stood just outside the open sector. He had watched Synapo and Sarco drop, but had not distinguished them from the rest of the blackbodies which, a half-hour later, began to fall from the sky like the gentle descent of a black snow that melted to bright raindrops as it neared the surface, raindrops inversely and miraculously suspended above the trees in defiance of gravity.

When the tiny amount of absorbed sunshine began to warm Synapo's reflector the next morning, he awoke and began to deflate. When his hook dangled free, he sucked in his tether and drifted to the ground, gently bouncing off the outer foliage of the tree.

When he reached the ground, he unsealed the front seam of his reflector and pulled it around him like a bathrobe to preserve his body heat. On his two short legs, he waddled through the forest to a small brook. Sarco was already there, having breakfast and waiting for him. His hook was turned to the back in nonaggressive posture, which was a good sign. Still, he was having breakfast. You could hardly expect anything else. Anger cannot abide alongside intense creature satisfactions.

During the night, the feathery cold-junction that protruded from Synapo's rump had warmed, and the millions of hot junctions distributed throughout his lampblack hide had cooled, so that both cold and hot junctions were now at the same median temperature; and he had fasted throughout the night. Now as he backed up to the brook beside Sarco, drew his reflector tight across his back to bunch it in front of him, and squatted to dip his cold junction into the icy water, he sighed contentedly as the fresh juice flowed into his storage cells. That fresh shot each morning was the best juice to be had all day.

Neither spoke, which was the custom at breakfast, nor would they speak until they were again on the wing. Speaking, unless forced by exigencies-such as the discussion with Wohler-9-was strictly a waste process, using the oxygen discarded from the electrolytic production of vital hydrogen. Electrolyzing when their hydrogen sacs were full, merely to generate oxygen for speaking, was a luxury they seldom permitted themselves and a necessity only under the rarest of circumstances.

That morning, however, Synapo again planned to allow himself only an hour on the wing before he resumed his discussion with Wohler-9. He timed it so that he could watch the Myostrians at work, as he had for the past several days. He was depleting his cells to well below what he found comfortable-he went around continually hungry-but at least he would be generating hydrogen during the discussion and not wasting juice as he would be otherwise. That was small comfort as his store of vital energy dropped lower and lower. But Synapo felt that discussion was vital, not for what it had revealed so far, but for what it promised to reveal in the future.

With breakfast over and the gores of their reflectors tightly rolled into black ruffled collars, they began the long climb to charge altitude. Synapo, with Sarco following, slowly circled upward with languid but powerful strokes of his great wings. He kept the hemispherical iridescence centered below, so that when he finished his short charge, he could drop rapidly to the open sector where he could see Wohler-9 still standing vigil, right where he had been as Synapo dropped to tether the evening before.

When they reached a comfortable altitude, Synapo slowed his flapping and rolled onto his back, a wingspread below Sarco, giving the other the dominant position as was his right as interrogator. That had been the status of their conversation the afternoon before when Synapo had terminated it unilaterally.

“Now, Sarco, you were saying?”

“Forget that,” Sarco said. “My tether was cut, and I was fuming yesterday evening, but it's no big deal. A new hook and a night's rest and it's the same as forgotten.”

Good,Synapo thought, but it wasn't an Avery, it was my own burning breath which sent you into far sunrise. He wouldn't have stooped to such a childish trick if the situation hadn't warranted it. The thought of that piece of unstatesmanship lingered, unsettling his conscience.

“What is important,” Sarco continued, “is getting the weather back under control and stopping the godawful screeching of those tin aliens on hyperwave. The weather I'll have under control as soon as my people finish neutralizing that node below. I figure to have the compensator complete day after tomorrow.

“But the hyperwave noise is about to drive us all nuts, Synapo. Haven't those metal morons heard of continuous modulation?”

“Of course. That's the way they arrived,” Synapo said. “But their discrete modulation of hyperwave and our small discomfort with the crosstalk on our continuous channels is a minor problem. The real problem is your construction of the node compensator. It's a mistake, Sarco. You'll have deactivated the aliens only temporarily. And if I'm right, as I am more and more sure I am, you'll have succeeded merely in deactivating a bunch of servants, and probably not for long, but you will have irritated their masters sure as the Great Petero is our guide.”