Seasoning
(1978)
Isaac Asimov's Science Fiction Magazine, Sept - Oct 1978
Hal Clement

	The onshore wind had slackened, but was still strong enough to make the sturdiest bushes lean inland. The little sloop should be able to beat out against it, but Faivonen couldn't help watching. The Fahamu was his only link with the rest of Medea's humanity – a small population, but the only one that could mean anything to him now. Earth's billions were no longer part of his life.

	Sullivan had promised to be back by midsummer, thirty Medean days from now. Faivonen trusted him, of course, since unreliable people had been pretty well combed out of the colony's leadership, but any commitment on the new world carried the unspoken qualification, "If I'm still alive." In spite of the numerous children, there were very few more human beings on the satellite than had landed two decades before. Learning as much as possible as soon as possible about the new world was admitted to be a necessity for the colony, but had been hard on individual members.

	Faivonen, though his enjoyment of society had died with Riita, had not become a misanthrope, and he could not bring himself to turn his back on his vanishing friends just yet. There would be plenty of loneliness, not mere solitude, for the next couple of thousand hours, even with Beedee along.

	The vessel was getting hard to see, but he could make out that she was going onto the starboard tack, after a long reach which had carried the individual figures of her crew well out of sight. The light was dim, probably dim enough to have made him give up the watch thirty years before; but the human eye is adaptable, and the human memory constantly edits the standards of what can be expected. Even though the principal suns were not up yet, their location below the horizon revealed only by flecks of hydrogen crimson from their vast halo of prominences, Castor A and B were nearly overhead. Together they provided less light than Earth's full moon had done, but it was enough to satisfy him.

	"They'll clear the bay on the next tack." The voice was only slightly filtered by the speaker in the man's left ear; it would have sounded perfectly human to anyone not acquainted with the being who had spoken, who could hardly have been less so. Faivonen, without even glancing down at his arm, nodded.

	"That was my guess. Are you making a linear extrapolation, or allowing for wind changes?"

	"The wind will grow weaker for hours yet. Of course I allowed for that." There might have been indignation in the voice. "I have no reliable information on the currents, of course, but with no river flowing into this bay they should be simple. Are you going to watch the ship out of sight? That will waste valuable hours."

	"I'll watch for a while. There's no use getting started until the real suns are up, and there's nothing to check before we go. You wouldn't have let me forget anything important, and even if you had there'd be nothing that could be done about it now.:

	The voice made no answer; its owner knew it had taken the man's thoughts away, to some extent, from his vanishing companions. Faivonen, however, had little else to think of for the moment. The job ahead was already planned in as much detail as possible; it was to stay alive and to learn what he could about as much of the area as he could cover – preferably, but not quite as necessarily, in that order. If he didn't actually manage to stay alive, the things he learned could still be useful as long as his body and Beedee were found. It was this fact that had gripped his thoughts for the moment – the fact, and the memory it always evoked. He himself had found Beedee on Riita's skeleton; he had been searching for her, against the best advice. Success had made him for a time almost useless to himself, to their children, and to the colony. This time, he had extracted a firm promise from Sullivan: if Faivonen himself should fail to reappear to meet the ship, and it was decided that someone must go after Beedee and the information, it was not to be any of his and Riita's children. It was all right if they turned out to be explorers when they got old enough – as they nearly were, he suddenly reminded himself – but that sort of picture was too much to inflict on anyone of closer status than casual friend. The kids couldn't – 

	"Watch the ship, if you must, but get your mind off that line," Beedee's voice cut into his thoughts. "If you have nothing more constructive, or less destructive, to do than brood, I insist on getting started. The suns are practically up."

	This time Faivonen did glance down at the object strapped to his left wrist. He knew that Beedee could not actually read minds. He – or she, or it; the man had vacillated about the correct pronoun for most of the twenty-four years since he first met Riita and her strange possession – could do a very good job of reading the expression of anyone it knew, however. During the twenty years of their marriage, and the year since he had found and inherited the black diamond, it had plenty of opportunity to get to know him.

	"You're in no position to insist on anything," he pointed out, as usual when one of their conversations reached this point. Beedee made the usual counter.

	"Very true, but you know I'm right. We can see well enough for research. Get the rest of your equipment on, and let's start."

	"I'm hungry."

	"Well, you won't eat anything but cheese until you get moving. You managed to kill one meal here at the shore an hour after we landed, but nothing else has – "

	"All right. Hiking is easier than arguing." Faivonen attached knife, shovel, canteen, cheese incubator, shoulder pack, bow, and quiver to various parts of his person. Then he took a last look at the Fahamu silhouetted against the dull red patch on the horizon where Argo had set a few hours before, turned his back on the bay, and set off up the valley.

	From the sea, this had looked like a product of glaciation. No one had been surprised, since it led toward the cold hemisphere. However, there had been no sign of any stream or river flowing into the bay, in spite of the heavy vegetation which could be seen from shipboard. The plant life itself was a little startling for the latitude – eighty-six degrees north of the equator – where Castor C gave very little assistance to Argo in heating the world. When a careful check failed to show even a cove where a seasonal stream might have emptied, it was agreed that information was needed. Elisha Kent Kane Faivonen drew the job of getting it.

	A few facts had been ascertained before the ship had hoisted sail. There were animals which could serve as food, and plenty of the plants whose sap would serve as culture medium for the "cheese." This was a mixture of gene-tailored bacteria which produced the half-dozen amino acids needed by human beings and lacking in Medean life forms – one of the very few products of advanced Earth technology which the colonists had retained. They had not wanted to be dependent on anything which had to be replaced from Earth, but had little choice in this matter. Terrestrial plants were still struggling to become adjusted to the satellite, and until real crops of these could be grown, people lived on native food and cheese.

	Faivonen kept well to the left wall – his own left – of the valley as he travelled away from the ay. This would get the better light when the suns were a little higher, and they did have to see. Everything had to be examined; plants, animals, soil, rocks, wind, weather. The wind had been blowing on shore and up the valley for days before the Fahamu had reached the bay; a surface wind blowing toward the cold side of Medea was another peculiarity to be explained, though the explanation might be as trivial as the explanation of local weather so often was. Beedee claimed a special interest, however, and was constantly asking the man to hold it as high as possible so that its delicate pressure senses could record air currents with a minimum of ground disturbance.

	Faivonen didn't object, usually. The black diamond weighed only about three quarters of a kilogram, a negligible fraction of the equipment he was carrying. Whether the thing should be called equipment or personnel was still an open question, of course; he knew it was of artificial origin, but could not bring himself to regard it as merely a computer. It said too many things which smacked of personality. Somewhere in the lattice of carbon atoms which formed the thing's basic structure was a tendency – programmed, grown, or learned – to imitate human speech mannerisms and even voices. When he had found it with Riita's body it had spoken to him with her voice ...

	They had reached an understanding on that, right away: Beedee had promised not to repeat the offense. Courtesy? Sympathy? Faivonen couldn't know, but also couldn't help thinking of the device or creature as a person, as his wife always had.

	Of course, a person is alive, and living things don't operate from such simple energy sources as the flow of heat from a man's forearm to a near-freezing environment, or the potential difference between two metal bracelets with human sweat as an electrolyte. Living things, when their energy sources vanish and they stop operating, don't start up again after indefinitely long periods of time.

	Beedee had been "dead" for over two years between Riita's death and Faivonen's discovery of her body. He(?) had been "dead" for over two billion years between the time he(?) had sunk with a surface vessel on the Earthlike world of his(?) makers, and the time he(?) had been discovered by Riita's grandmother on an airless planet, blistering under a red giant sun, in a pile of calcium oxide which had once been a deposit of marine limestone.

	Only machines can be turned off and on, so Beedee must be it, not he or she. So Faivonen's experience insisted – most of it.

	"Elisha! There is a fairly large animal beyond the bush – thirty meters at two o'clock. You're hungry; get ready!"

	They were two kilometers from the bay, and the man was even hungrier than when they had started; his bow was bent and an arrow nocked before the diamond had finished speaking. Silently, avoiding the ankle-high puffballs whose bursting would give audible warning of his approach, Faivonen stalked toward the bush. He was still a dozen meters away when a calf-sized creature with six legs leaped into view on the far side, clearly bent on departure. He put his arrow high in the trunk, between the first and second pair of legs. If it were like the animals he knew closer to the equator, it had no centralized heart; but a major aorta ran along its body just below the backbone. Severing the blood vessel or the major nerve cord should be equally effective. It was; the creature dropped on the next bound.

	Faivonen performed a combined butchering and anatomical dissection, with Beedee recording the data. Then he collected fuel, lighted a fire with pyrite and steel, and cooked a meal. He didn't enjoy eating it much; neither the Medean flesh nor the cheese was particularly tasty, but hunger was even less pleasant.

	He cut a couple of kilograms of the meat into thin strips for his next few meals, extracted the few remaining lumps of ripe cheese from the incubator's tank and put them in the storage chamber, refilled the tank with sap from the Cheddar plants he had already identified, and resumed his hike, after asking Beedee if his(?) own battery needed charging.

	"Oh, no – I'm running on – oh, you're being funny. Excuse me."

	It had happened before. The diamond's calculating processes, or reasoning if that was really what it could be called, operated at electronic speed; it had known he was joking long before its first word was uttered. Nevertheless, it had imitated a human double-take; it had been playing up to his humor. Whether it had felt anything corresponding to the strange relay-chatter with which the human nervous system responds to incongruity was something Faivonen couldn't guess. Whether it felt at all was an equally open question.

	By the time the Castor C twins were halfway around to their midday position a few degrees above the southern horizon, Faivonen was tired; even with frequent pauses to examine biological or geological data, they were more than thirty kilometers from the sea. He rested and ate again, and then settled into his sleeping bag. He knew that his own biological clock would never reset itself to Medea's seventy-five hour rotation, but sleep was as necessary as food; he slipped the blinders over his eyes and relaxed. Beedee would guard; it was unlikely that anything could approach without registering on its supersensitive pressure sense. Guarding might be necessary; Medean predators could get no more adequate nourishment from human tissue than the other way around, but none of them seemed to know it.

	This time the man was lucky, not waking up until Beedee's voice began hammering "Eight hours, loafer," into his ear. He sat up, slipped the pads from his eyes, and looked around. The suns were almost in the south, now, just above the spot where Argo had long ago disappeared. Two balloons floated a hundred meters overhead; Beedee might not have heard them, since they always seemed to ride the wind, but it didn't matter. No one knew much about the organisms – Faivonen wasn't even sure whether they were actually inedible, or merely had too little tissue to be worth hunting – but they were certainly harmless. At the moment they didn't seem to be moving at all, which was interesting.

	"Sullivan thought the wind was getting a little weaker each cycle," Faivonen remarked. "It looks as though he was right."

	"He was," agreed the diamond. "There was a pretty good chance of it when he was speaking, but there were too many unknown variables for real computation. You know, I am beginning to suspect that some of the variables lie in the shape of this valley. We'll have to get a long way inland to make sure."

	"Too far inland and Argo won't be rising at all. I want no part of Coldside," Faivonen pointed out. "You wouldn't like it either. There may be a lot to learn, but with your power off you wouldn't be learning it."

	"You could rig me a battery. I can think of ways you could set it up to operate even at dry-ice temperatures."

	"It gets colder than that – and you don't like being turned off any better than I'd like dying, even if you can switch on again."

	"I know. I hate to miss arriving information. Still, I believe right now that I'd like to take the chance; and I've heard you, and Sullivan, and many other people say that danger gives spice to existence."

	"I think we said life, not existence. And I know we said danger, not suicide. Forget it, Beedee; you stay with me, and I stop a long way short of dry ice even if this valley goes that far. You figure out what you can from the rocks and the weather and the life; that should be enough."

	"There is never enough. I can calculate, but then I have to see whether I was right. You should allow for that; your wife always did."

	Faivonen's silence was pointed. A human being would have been embarrassed at the faux pas, but Beedee didn't make such mistakes. He must have had – it must have had a reason, and it must have been a good one.

	The man knew that he probably wouldn't be able to guess it. The score of black diamonds which had been brought back by the Tammuz expedition had made no secret of their composition, though the knowledge had done human engineers no good – the techniques needed to make one of the things were far beyond current human ability.

	They were just what they were called – diamonds, structures of carbon with replacement atoms and crystal defects built deliberately into their lattices in ways which resembled mankind's operations on silicon chips for the last century or two – resembled them in much the same way that circuit chips resembled a flint knife. About twelve hundred unit cells of the diamond lattice composed a single basic structural unit of the devices; a much less reliable estimate, usually guessed at about five thousand, of these units had about the recording and decision-making capacity of a single human brain cell.

	The things themselves – Beedee was typical, though no two were identical – looked as though someone had made a cylinder of black glass a little over six centimeters in radius and not quite ten in length, fitted the ends with hemispheres of the same material and split them lengthwise into two units. With that volume – a little over two hundred milliliters – they had theoretical capacity for the equivalent of not quite 200,000,000 four-billion-cell human brains. Some people were afraid of them, and there had been loud demands – to destroy them or get them off Earth – by some of that planet's more paranoid inhabitants. It had not been entirely the high regard for private property rights characteristic of the culture of that time which had allowed Beedee to come to Castor.

	Faivonen himself was no more afraid of the thing than his wife had been, but he took for granted that it could think many times faster and with far more precise consideration of myriads of variables than any human being could. It had been one of Beedee's fellow machines, or beings, who (which?) had proved that chess was as trivial a game as tick-tack-toe.

	Some people had not forgiven them for that.

	Faivonen didn't go back over all that, consciously. He merely wondered why Beedee had mentioned Riita when it knew the man would be pained, assumed he would not be able to guess the answer, and turned to the day's work. He cooked and consumed another meal, loaded up his equipment, and not until they were under way did he speak to his computer-recorder again. Even then he changed the subject to one of more immediate importance.

	"There's still no river in this valley--"

	"There could hardly be one at all, if none reached the sea," Beedee pointed out.

	"There have also been no pools or puddles, though there is plenty of vegetation. I'm halfway through this two-liter canteen. Have you any practical suggestions?"

	"There is snow visible at the top of the cliffs from the sea. The temperature here is distinctly above freezing. Some water should flow over the edge, if only occasionally. Let's examine the base of the cliff more closely; the geological information will be useful in any case."

	Faivonen refrained from comment, and started toward the nearer side of the valley. They had already learned that the valley had been cut in sedimentary rock--a fine sandstone--whose present elevation above sea level implied much about the tectonic forces available on Medea. There was rubble, inevitably, at the foot of the cliffs. Near the bay, this had been deposited so as to give a U-shaped contour to the valley, leading the explorers to assume former glaciation; closer examination had revealed only very fine material which appeared to be wind-borne. This far from the bay the roundness persisted and was even exaggerated; the cliff, on this side at least, seemed slightly undercut.

	Away from the walls, the soil was a fine-grained loess. Closer in, it contained rocks whose size increased with decreasing distance from the cliff. Exposed portions of the rocks were well rounded by some form of erosion.

	The soil itself was very dry, in spite of the abundant vegetation. The man had dug up several of the smaller plants, and found that their root systems did not go particularly deep; Beedee had agreed with his conclusion that there must be a fairly frequent supply of surface or near-surface water, since the plants themselves showed nothing unusual in the way of liquid storage capacity.

	The diamond, as usual, was right; the soil was detectably moister near the cliff, and part way up the slope they found occasional shallow puddles where the rocks had made dams to hold them. With a good deal of relief, Faivonen took the first long drink he had allowed himself since landing, and refilled his canteen.

	He was in a better humor now, willing to go on farther toward the cold. His garment was another bit of Earth technology which had been kept for special uses, a coverall of thin polymer whose thermal conductivity was extremely low, though it was quite transparent to near infra-red radiation – he could appreciate the heat of a fire or of the Castor C twins without having to take off anything to let the light in. With a headpiece like an ancient skiing mask, he would be able to face air temperatures well below the freezing point of water, even with fairly high winds. Dry ice temperatures would be something else, but it should take many days of travel to bring him anywhere near that sort of environment.

	He chatted good-naturedly with Beedee as they resumed their way up the valley, slanting back towards its level floor where walking was easier. The discussion was almost entirely about the facts they were observing – the diamond was seldom willing to play human to the extent of indulging in gossip or idle chatter – but it included some speculation. What had elevated this entire region of sedimentary rock practically as a unit for more than five hundred meters? Beedee had made several dip measurements where the exposure permitted, and nowhere found more than two degrees. What had cut this canyon, if not a river or glacier? And if it had been a river or glacier, why was there no trace of it now? Valleys without central streams are most unusual except the ones in deserts – and even those usually have empty stream beds where water once flowed.

	The two balloons had drifted down the valley – the wind had finally reversed, instead of merely slowing down. Could this be a tidal phenomenon, as Sullivan had guessed as they were approaching the region in the Fahamu? Beedee agreed that it could be, but declined to risk a prediction.

	If this is really a tidal current in the atmosphere, and is being funnelled into this valley from both ends, the width of the valley itself, the height of the walls, and the size of the feed areas are all relevant. At the sea end the supply reservoir is effectively infinite, but we have no observations about the other factors. Guessing that the canyon keeps its present width and height for its whole length is pointless as long as I don't know the length or the other variables. I can treat it mathematically as an organ pipe of rather unusual cross section with a forced input of one Medean day's period, but – "

	"Forget it." Faivonen was a perfectly good mathematician as human beings went, but knew the futility of trying to follow Beedee's brute-digital-force "estimates." "You keep your ideas inside, and we'll check their accuracy as we get farther up the organ pipe. Isn't that a new plant?"

	"Not really. It's quite common on some of the islands near the equator. It is the first time I have seen it so far north. Of course latitude means much less than longitude here as far as climate is concerned." The last sentence came after a slight pause, as though it were an afterthought.

	"Yes, I keep forgetting. It was very tactful of you to talk as though you forget too, but I don't really need that kind of coddling. I know what your brain is like."

	"Does it offend you? I have noticed that most human beings seem more at ease when I use such conversational artifacts."

	"Well – no, not really. Just don't ever let it waste time if we're in trouble."

	"Of course not."

	Whatever Faivonen may have thought consciously of Beedee, his feeling toward the thing was essentially ordinary friendship. It was a personality. It was even a person. Their running conversation might almost have been taped at a dining table during a scientific convention; and for the first two Medean days it was little more exciting than dining-table talk. The only complications arose from the endless phase problems between Faivonen's twenty-four- hour cycle and the satellite's seventy-five-plus-hour rotation. He had to waste waking hours at "night". The white suns and the continuous aurora gave enough light to permit travel when the orange suns were below the horizon, but the man and the machine were both reluctant to do this. Seeing was poor enough to give a high risk of missing important data, a possibility which bothered Beedee even more than it did the man. Gathering and storing information was the diamond's prime motivation – its equivalent of hunger, thirst, and libido combined.

	On the third day, Faivonen was awakened early from his morning sleep by Beedee's voice in his ear.

	"Elisha! Something is trying to creep up on us very silently! Have weapons ready."

	The man snaked out of his sleeping bag as quickly and quietly as possible. "How far away?" he asked, wondering whether bow, axe, or knife would be most appropriate.

	"I cannot tell the linear distance, since I don't know how much sound energy it is producing. If it maintains its recent average rate of approach, it will arrive in about one hundred seconds."

	Faivonen was on his feet by now; he nodded, seized the bow, and nocked an arrow. "Direction?" he asked.

	"Four o'clock from where you're facing now." The man whirled to his right. Nothing was yet visible, but there were many shrubs up to three meters in height which blocked the line of sight. He could not hear anything yet; the hard-packed soil was almsot completely covered with the bladder-covered, mosslike growths which filled the ecological niche of grass over much of Medea's surface, and even a very heavy animal would have made little noise.

	Argo was just rising, and its dull red disc, rimmed on the upper left by the brighter crescent where the twins lit its farther hemisphere, provided a blood-tinted background against which the newcomer should be silhouetted any moment. Faivonen wondered whether the creature was following his trail, or had simply winded him – the air tide, if it were actually that, had gone much more negative during the last couple of cycles and blown a stiff breeze down the valley toward the sea. This had fallen in the last few hours as the fire-planet rose, but could still be carrying the human scent to anything down-valley equipped to detect it.

	"It's stopped. It's only breathing now," Beedee said suddenly. Faivonen lifted his bow, and drew the arrow part way back. Some of the Medean predators could leap many meters – 

	This one didn't. It suddenly came into sight to one side of a large bush, running toward him at high speed. It was moving too fast, and the back-lighting was too poor, to let him count legs or spot other details; but research didn't occur to him until later, anyway. He drew the shaft back the rest of its length, aimed as best he could in the second or two available, and loosed. The creature swerved slightly, knocking him off his feet as it brushed by him. It must have had twice his own mass. He struggled back to his feet as rapidly as his muscles would permit, dropping his bow and drawing his machete.

	"Relax. It's still running. Your arrow is about half-shaft deep in a front left shoulder; you hurt it badly, perhaps killed it."

	"Any other details?"

	"It was a species of lancer, the largest I've seen. It had a radula – the toothy-tongue arrangement they all do, and was running with tongue extended. If you had missed with that arrow, the tongue would have hit your throat and left very little of your neck. I thought of telling you to dodge, but it was obvious that your reaction would have been very much too slow."

	"And it's still heading away from us?"

	"Yes. I see no likelihood of recovering your arrow?"

	"That wasn't quite what I was thinking about."

	At least, the incident killed boredom for a time. The diamond claimed not to understand this pointing out that if Faivonen had been killed he would have attained ultimate boredom. Faivonen failed to see any humor in this, but couldn't help wondering whether Beedee were actually trying to display some such human emotion. He put a leading question.

	"Do you really want all your predictions fulfilled and your calculations correct? I've heard you say that your fun consists of checking your figures against observation. Isn't it sort of – well – deadening if you're right all the time? Life needs some kind of spice."

	"I assume you speak figuratively, if the word you just used actually refers to the taste-only foods you left on Earth. I am aware that no research can be done without a little risk, but fail to see how adding to the danger improves the taste, if that matches your figure of speech, of learning or discovery."

	"You're just trying to make yourself sound more like a machine," retorted Faivonen.

	"Gambling should obviously be saved for the time the odds are with you. My knowledge of human gamblers is limited, but manipulating the odds in their favor has always appeared to be one of their standard procedures."

	"Those weren't gamblers. Look – you've just won a bet, since your existence is tied in with mine. If you don't get a kick thinking about that, you're just not alive."

	"I have never claimed to be alive," was the diamond's rather overwhelming answer. "Thank you for forgetting."

	Faivonen could think of nothing to say.

	There was no more night, even the brilliant night of aurora and the white Castor suns. The trip had started at the equinox; four Medean days later, sunrise and sunset points had met ahead of the travellers. The Castor C twins were in the sky for the rest of the journey; they would not set for thirty of Medea's revolutions around Argo. This at least resolved the question of whether or not to travel at night.

	No more attacks were experienced in the next few days, and boredom again began to threaten the morale of the human member of the exploring team. On the seventh day he felt the need to do something about it.

	Beedee, with its precise visual sense, had measured the distance they had travelled, mapping the valley as exactly as the human was ever likely to find necessary. They were now just over one hundred and fifty kilometers from the bay as the balloons travelled – as many of them did. The winds were increasing in speed both ways, and more and more of the organisms were apparently getting swept into the valley. The down-valley winds, back toward the bay, were less intense and shorter in duration than those blowing from behind the travellers, but a change in both qualities was becoming evident as the days went on.

	"Beedee," Faivonen remarked as he finished a breakfast during the seventh day, "I'm getting a little tired of waiting for something to happen. I was inclined a couple of days ago to liven things up – season this meal of knowledge you find so tasty – by making a bet or two with you. Then I couldn't think of anything either of us could use to pay off with; but I just have. The only trouble is that I'm not sure any bet could be really fair, since you can calculate things so much better than I can. Still, it's worth trying, if you'll tell me the truth."

	"Trying what? Why should I tell you anything but the truth?"

	"To the latter, I don't suppose you would; it would demand human characteristics you claim to lack. What I want to try, as I said, is a bet. For example, I've been wondering about those balloons – they're being carried farther toward the cold side than back this way by the winds, so far. If they get there, it's hard to see how they could do anything but freeze. We could bet on how much frozen balloon there is in the glaciers we both believe are a few hundred kilos along, with the uncertainties being things like natural methods of escape which I haven't been able to think of.

	"Or we could bet about the winds, which we both think are affected both by the season and the tides. How intense will they get by, say, the third noon from now? I can only extrapolate roughly, and you say your calculations wouldn't mean anything without data on the shape and length of the valley and the area beyond that feeds wind to it."

	"True. My set of possible solutions so far is so broad that any one of them could qualify as merely a guess. Yes, we could bet on that; but what possible currency could we use?"

	"If I lose, we go fifty kilometers farther than the point where my judgement says we ought to start back. You will collect that much more knowledge."

	"A very tempting offer. Will you state in advance the criteria on which you would base that judgement?"

	"Don't you trust me? I can give you several, actually, but can't guess which might happen first or demand highest weight. For example, if we went twenty hours or so without finding a food animal, I'd certainly think about return. If wind-chill got too close to the lower limit at which this suit could keep my alive ..."

	"But if we went beyond these points, you might die. Those are the same sort of factors which would make me recommend turning back."

	"Well, that would be just another bet. If I didn't survive, you'd still be found sometime, so you'd be the winner again."

	"I don't want to be turned off, even temporarily. I wouldn't regard it as a win."

	"And you won't bet?"

	"No. What are you trying to arrange" You haven't suggested what I should pay you if you win. I have never heard of a gambler who didn't have that factor his prime concern."

	"I told you – you've never met a real gambler. I'd be content with being right in a dispute with you. Didn't Riita ever challenge you to anything like that – both make predictions, and see who was right?"

	"I  thought you didn't want to discuss her with me. It seemed to cause you grave emotional distress."

	"This si not a discussion. I simply asked a question."

	"Yes, she sometimes tried to outguess me about what was to happen, but she never made a formal challenge of it."

	"Well, I want to."

	"I get the impression that you are trying to confuse me. The set of possible explanations – or rather, the set of explanations I can think of – for your action is larger than the set of possible solutions to the problem of the valley wind."

	"I have thought of something you could pay me. Just stop with those artifacts. The correction in your choice of words was intentional; you had planned that sentence long before the first sound wave came out of the speaker."

	"You said that this did not bother or annoy you."

	"It's beginning to. It reminds me, each time you do it, how much faster your brain works than mine does."

	"Then I will stop. No bet is needed."

	"Thanks – I guess. Well, I'm making a prediction anyway. I say that the wind coming down this valley at noon on the third day from now will have a speed greater than seventy-five kilometers an hour. Do you agree?"

	"This is very close to the median of my set of possibilities."

	"What's the median?"

	"Seventy-seven point one four."

	"All right, I say it will be higher than that – or do you want to take the high side?"

	"I see no basis for a choice. Let it be as you say. I will not, however, hold you to the pledge of extra distance if you turn out to be wrong."

	"You can't stop me from paying off if my conscience demands it," pointed out the man.

	"You mean you are doing all this to remind both of us that you control all our actions? It seems silly."

	"I hadn't thought of that. Thanks."

	"I wonder if that is really true."

	Faivonen made no answer, though the diamond's remark startled him considerably. He fell silent and gathered up equipment in readiness for the 'day's' next hike. The suns circled the horizon, hiding first behind one set of cliffs and then the other.

	Some ninety hours later the trip became interesting again without the aid of bets. Over a space of about two kilometers the hard soil of the valley became first slightly damp, then quite wet, and finally coated with frost. The man's first thought was radiation cooling, even though there had been no real night. Then he noticed that the frost extended about equally far on both sides of the valley, and part way up its walls, as though something had come down to this point to chill everything, and then retreated. The fact that frost crystals grew as deeply on the underside of branches and overhung rocks implied the same: things had cooled by some other process than radiating to the sky.

	"This is a good one," Faivonen remarked aloud. "Any ideas?"

	"Of course," replied Beedee. "This fact has narrowed my set of possible solutions by more than ninety-five percent."

	"Where does it leave my bet?"

	"You are well ahead. You are also in about fifty times as much personal danger as I had estimated."

	"How bad is that? You mean we should turn back now?"

	"I should be able to give you warning. Actually, the estimate remains grossly unreliable in view of the unknowns in the physiography ahead of us. If you are willing to face the risk of learning more of the pertinent facts, I most certainly am."

	"But what caused this frost? And why is it taking so long to melt, even with the suns shining on it?"

	"Before I answer that question, I must ask you one – one which involves your wife. Do you object?"

	Faivonen hesitated, then said, "Go ahead."

	"It was her very clearly expressed wish that I not solve a problem for her which I believed she might reasonably solve by herself. She may never have told you in so many words, but she did not wish to become dependent on me; she felt some guilt about bringing me to Medea at all. She fully supported the policy that you colonists should not be or become dependent on anything they could not produce here. If you share her policy views, I cannot answer your question. I know you have enough data, and I think you have enough reasoning power, to solve it yourself."

	Faivonen thought silently for several seconds. He was willing to take on the problem himself – it would help fight the boredom of pure fact collecting. However, he was less sure of the general policy suggested. Beedee, in spite of the need for independence, was highly important to the colony; it carried most of the data so far accumulated about Medea in its memory. Some of the group had objected to letting the device go out on exploring trips, yielding the point only because so much better quantitative information could be obtained through its senses. Several of the Fahuma's crew had been clearly more concerned about the machine than about Faivonen when they left the ship.

	If, as Beedee had just said, the danger was now greater, perhaps it would be better to turn back now and get the information so far gathered back to the colony.

	On the other hand, as he was quite sure the diamond would claim, what they had learned already would be greatly multiplied in value if more were known about this area; the local meteorolgy, especially, would provide clues to the cold-side conditions which might take years to gather any other way or from any other place. It was not just a matter of Beedee's burning thirst for information; Medea's weather, and still more its climate, could be very literally matters of life and death for Medean humanity. There was no way of getting knowledge without risk, and knowledge itself was life.

	"All right," he finally said. "I'll figure it out myself. Let's go on." Beedee approved briefly.

	The suns were slowly melting the frost from the branches and leaves of the bushes, but were making much less progress with the coating on soil and rocks. The presumption was that the latter had been chilled to a considerable depth, which in turn suggested conductive rather than radiative loss of heat; beyond this, for the moment, Faivonen could not get. The only change made by ten kilometers of travel was a thicker frost; with some evidence of snow as well – piles of feathery crystals which had apparently blown into sheltered areas by wind coming down the valley, and then strangely, had had frost crystals grow on top of them. The distinction between the material which had blown from elsewhere and that which had grown in place was quite definite, according to Beedee, and Faivonen himself could see it.

	He could not see the physical situation which would produce such a phenomenon. There had been no clouds even a few kilometers down the valley; it was hard to see how snow could fall without them. On the other hand, it was hard to see how radiation cooling sufficient for frost could occur if clouds were present. A brief show shower, possibly, followed by a quick clearing, would explain things after a fashion. However, it did not explain why he and Beedee had seen nothing of the shower. Such a phenomenon should have been part of a travelling system – a weather front; and why such a thing should have stopped and retreated, or died out after coming within a few kilometers of the last camp, was hard to see. There had not been a cloud; all that either of them had seen in the sky since the suns had stopped setting had been the balloons.

	These had been floating in ever-increasing numbers, sometimes back toward the bay, sometimes passing the explorers on the way toward the cold side. The tides, if the valley winds really were tidal phenomena, still seemed to favor motion away from Argo.

	The creatures seemed to be drifting lower each day. A hundred hours ago some had been only a few tens of meters up; now many were practically skimming the frost. It occurred to him that the converse was also true. However, he refused to worry, as usual.

	"I suggest," Beedee cut into this line of thought, "that we examine some of the clefts or chimneys in the cliff. We might get more evidence about the nature of this strange heat sink."

	"All right," agreed the man. "While I'm climbing, you might look out over the valley for animal life. We're short of meat, and I can't live indefinitely on cheese. I can't help wondering whether this freeze may not have driven the local animals away, or into underground hibernation, or something like that."

	"A good thought," agreed the diamond. "It would be a pity to have to turn back just as data are starting to cut down the possibilities to a really manageable set. I predict that the valley will at least double its width in the next ten kilometers."

	"I'll go that far without any food, if you're that near a solution. But let's check this chimney first."

	The feature in question was a fairly typical crack, ranging from one to two meters wide, in the cliff wall. It appeared to start at the point where the rock itself became nearly vertical; probably it went lower, but was hidden by the rubble which formed the rounded base of the wall. A climb of nearly a hundred meters was necessary to make the study they wanted.

	This took only a few minutes. The numerous projecting rocks which served as steps were worn very smooth, presumably by blowing dust or sand, but were so firmly buried in loess as to be completely safe. With frost crystals crunching under his feet, Faivonen took a zigzag path to the bare rock; from that point he was able to follow a shelf where coarser and evidently softer sandstone had been eroded away, straight to the chimney itself.

	The examination was brief; the crack was almost solidly choked with frost.

	"Not radiation cooling," Faivonen remarked categorically.

	"I agree," replied Beedee.

	"You know what did it." The man's words were a declaration, not a question.

	"I believe I have a unique solution for this aspect of the problem."

	"And I should be able to find the same one."

	"You should. All pertinent data are available to you."

	Faivonen thought deeply as he picked his way back down to the valley floor and headed up the valley once more, but failed to come up with any solutions, unique or even believable. Increasing hunger finally diverted his attention from the problem.

	"Did you see any animals while we were up there?" he asked the diamond.

	"None, nothing moving in any part of the valley I could examine. I did not mention it because you said you would go at least ten kilometers farther anyway."

	"Thanks. What do you think the chances are of finding them in this frozen area?"

	"I have not enough information for a reliable estimate."

	"Could these animals survive the conditions which you believe caused the frost?"

	"Not by any special physiological machinery we have found in them. Such techniques as hibernation would involve biochemical factors not obvious to gross examination, of course."

	"Could I survive those conditions?"

	"No."

	"But you can warn me in time to escape them."

	"I believe so. There are variables – "

	"I know there are variables, blast you. Are you walking me into something I'd have to catch a couple of dozen balloons to life me out of?"

	"That number would be insufficient, and you might have trouble securing their cooperation – "

	"Cut it out! You know perfectly well when I'm being figurative!"

	"I am never certain about it. Your wife was much easier to judge in such – "

	"Shut up!

	Faivonen strode on in silence for two or three kilometers. After the first five minutes or so, he realized that Beedee had done a competent job of changing the subject on him and he still didn't know how much risk he was taking; but he didn't see any use going back to the matter, and he felt reasonably sure that the diamond would not take really serious chances with its own transportation. Gradually, he cooled down to the point where he could pay attention to his business once more.

	The frost was slowly vanishing from the near side of the valley, under the rather unimpressive glow of the twin suns – a glow currently reduced by the fact that one of them was eclipsing the other. Argo, the real heat source for its satellite, was too low to help even if a slight turn in the canyon, some scores of kilometers back, had not blocked its radiation from the valley floor anyway.

	When he finally spoke to Beedee again, it was not about personal risks.

	"How much useful information do you really think we can get by going, say, a hundred kilometers farther, if that is possible?" he asked. "We have a good idea of the local geology – at least, as good as we can get without drilling – and an even better one of the biology and ecology. Of course, any additional information is always good – I go along with you on that, even if I don't have your burn for detailed knowledge – but aren't we maybe getting to the point where what we've already learned should be brought back and reported?"

	"In those fields, perhaps yes," was the answer. "However, the meteorology still baffles me seriously. We really must learn more about the atmospheric tides which I believe are controlling so much of what goes on in this valley. If I can work them out in detail, I believe we can infer more about the physiography of the cold side of Medea than could be learned by many hundreds of man-days of surface mapping even if men could venture there. I consider it vital that we go on for a while yet."

	"Regardless of risk." It was not a question.

	"Not entirely, of course. I will do my best to keep you well enough informed to get us back safely, though like you I accept the fact that research entails risk. After all, while I was quite certain that you would come looking for your wife and therefore would find me, I am not nearly so sure that anyone would – or could or should, I this part of the world – come looking for you."

	"They'd surely come for you."

	"I doubt it. Sullivan would be the most strongly tempted, but would certainly not leave his ship. I would not be willing to bet my consciousness on the chance of someone else on the Fahuma coming, even if Sullivan were willing to work such a trip into the ship's schedule. I am as strongly concerned about your safety as I was about – " The machine's voice broke off.

	Faivonen knew what the missing word would have been, just as well as he knew that the interrupted sentence had not actually been a mistake; it was another deliberate action by the diamond. He decided not to play up, this time.

	"All right. We'll go on for at least twelve hours, unless you warn me back. Keep your senses tuned up for animals please. The food situation is getting a little tense."

	Beedee acknowledged the request, and another score of kilometers were traversed with little worth noting except the melting of most of the frost and the fulfilling of Beedee's valley-width prophecy. They finally stopped for rest. There was nothing to eat but cheese, since they had seen no animal life, but he lit a fire anyway; and with some trouble, dug a shallow sleeping pit in the not-quite-frozen ground. The wind was starting to strain the performance of coverall and sleeping bag; balloons were now sweeping by them from behind at running speed, at times bouncing against bushes.

	"Do you suppose it's the low temperature that brings them down this far?" the man wondered aloud.

	"Not for simple physical reasons. A given mass of hydrogen or other light gas would have the same lift in a given atmosphere at any temperature. The balloons do not seem to have shrunk, and a temperature drop for a given volume, if shared by the surrounding atmosphere, would increase the lift. Of course, if the creatures can alter internal pressure by muscular contraction of their sacks, or do something to raise internal temperature, the set of possible responses is greatly enlarged. A detailed examination of one of them would be interesting and useful."

	"Hasn't anyone done it already?"

	"It has not been reported to me. The creatures seem to have been given a very low research priority after being found inedible. I would not have approved, myself, of such an evaluation."

	"Naturally not. Well, we'll fit that in if we can. Stay on your toes; I'm going to sleep for a few hours." Faivonen slipped the blinders on.

	He woke up five or six hours later, unpleasantly chilled. Keeping as low as possible behind the low pile of soil he had excavated – the wind was not strong, but very noticeable – he placed most of the fuel he had stacked beside his sleeping pit to help break the wind on the remains of the long-dead fire, and lighted it. When it blazed up he rose to sitting position to let is radiation reach more of his body; and as he did so, Beedee's voice – no, it was Riita's voice! – suddenly sounded.

	"Elisha! Get to the cliff and start climbing at once! Waste no time!"

	Being human, Faivonen did waste a little time. He reached for the equipment he had discarded on lying down, which cost him a second or two; as he ran toward the nearby valley wall, still fastening gear about his person, he looked up the valley and almost lost several more.

	Some kilometers away – he could not judge more precisely – an almost featureless white cloud was bearing down on them. It spread low across the valley from wall to wall. Its upper surface was sharply defined, but he could see for some distance into the lower portion. Its height was somewhat under half that of the canyon walls.

	From ground level he could not judge its speed, but had a strong impression that it was approaching rapidly. Beedee's evident opinion that it was dangerous could probably be trusted, anyway, and Faivonen ran his hardest.

	It was only a short distance to the point where the wind-rounded rubble began to slow him down. It also, very shortly, brought him to a height where he could judge the distance and speed of the menace for himself. Neither item of information was encouraging. He saw little chance of getting above it before it reached him, but he had no idea of giving up and spending the time before it arrived in thinking up reasons why it was probably harmless.

	Details became clearer as the thing drew closer and the man climbed higher. He remembered seeing something like it in a museum on Earth, in a wave demonstration tank where two immiscible liquids sloshed back and forth. He remembered the crawl of the denser fluid along the tank bottom as the container slowly tilted, and how the lighter material was forced up and out of the way.

	He remembered pictures of a similar situation which he had seen later, when he was studying meteorology – the cross section of a cold front ...

	And suddenly he realized what it must be, and redoubled his climbing effort. Cursing his own shortsightedness could come later, when the breath might be available.

	"Beedee!" he panted, "I suppose this was your solution. I take it you didn't call the time quite correctly."

	"It is. I couldn't. The region beyond our sight must broaden into a bowl in its general arrangements, but I have no data on the bowl's size. Hence, the sloshing of the dense gas under tidal influence has a natural period which I was unable to calculate, though the observed changes in the valley wind eliminated many possibilities. There must be funneling effects at various places along the valley, and these are quite impossible to calculate. There must be some critical time, as spring advances, when the contents of the bowl not only pour for some distance down the valley but actually start a siphoning effect. I trust this is not the time. When that happens, there will be a high, uninterrupted wind of carbon dioxide all the way to the sea – no doubt the cause of the peculiar erosional features we have observed from the beginning."

	"I guessed about the CO2 when I saw how sharp the upper surface of the gas river was. It's the coldest cold front anyone every saw – "

	"Don't waste your breath in speech. You seem to have analyzed the situation correctly, but you will have to get above that gas surface or drown. You probably see now as well as I do how the thing formed in the first place, but this is not the time to discuss it. Climb!"

	"All right. Just don't use Riita's voice again, no matter how urgently you want my attention."

	Beedee made no answer to this, and Faivonen continued up the steepening slope, still snatching occasional glances at the approaching river of frigid gas. Its boundary was clearly marked by the water it froze out of the air it met. Tiny snowflakes settled through it, giving the mass a foggy appearance from a distance. The upper surface looked sharp mostly because the man's line of sight was nearly parallel to it.

	It was also marked, he saw as it drew nearer, by larger specks which he finally realized were balloons. Their buoyancy, as he and Beedee had seen, was for some reason low enough to let them reach the ground in ordinary air, but they floated on top of the carbon dioxide to emphasize the outline provided by the snow.

	Looking back and down, in the brief instants he dared do so, he could see the creatures being scooped up as the front reached them. They looked as helpless as he was beginning to feel. His arms and legs ached, his breath was scratching at his throat, and his heart was pounding. He was tempted to drop some of his equipment, but it was already at a minimum likely to keep him alive if he got through the present jam.

	The front at the valley floor level was within a kilometer of his camp – farther back, thank goodness, at his present height – it had a shallow slope; every meter he climbed was giving him more time – that could be a good calculus exercise – no, waste of time, Beedee must have it figured out already except for a few variables involved in terrain he was trying to climb over – it was funny what a person's mind would do when it wasn't being put to important work.

	Now the ground-level leading edge of the front had passed below him. The valley to his right was floored with a foggy whiteness which became sharper and more opaque as the eye followed it toward the horizon. The top of the snowstorm was climbing toward his feet, the site of his camp disappearing through the thickening precipitation. The fire had vanished between two breaths; its only trace a vague patch of smoke which had been lifted like the balloons and was spreading into invisibility as it rose toward him.

	"Elisha! To your right – ten meters – a chimney. Get into it!"

	"Why?" Faivonen slanted in the direction mentioned, even though the reason was not yet clear to him. "It will fill with gas as quickly as the rest of the valley, and there's no reason to suppose I can climb any faster there."

	"You probably can't, but I sense turbulence at its edges. The gas is mixing with air there, and should remain breathable longer. Try it. As I read the currents where the front has reached it lower down, there must be good air being forced up from below inside the crack."

	Faivonen didn't see what he could lose, and where hand- and foot-holds permitted a choice he favored the way toward the opening. He was by now well above the talus and climbing bare but greatly weathered rock. As has been the case farther down the valley, occasional layers of softer sediment had eroded more rapidly to provide shelves and steps; the climbing was not essentially difficult, but hoisting his eighty kilograms of self and equipment even with good footing at the speed which seemed necessary called for a high power consumption.

	But climbing inside the chimney would be too slow, though he knew the techniques well enough. Beedee saw this, once they were able to look in, as quickly as the man did.

	"Stay as close as you can. There'll be oxygen for longer. Another fifty or sixty meters will get us out of danger anyway."

	"I – "

	"Don't talk! Keep quiet and climb! I'm talking so you won't. Listen all you want, but if you disagree with me keep it to yourself until later. I just remembered another factor; I wish I could evaluate it numerically. The gas lake feeding this river must not only be sloshing under tidal influence, but be expanding thermally as spring advances. It's getting deeper, and would overflow down this valley, I judge, even without the tides. The diurnal variation in solar heating would have the same frequency as the tide, of course, but probably not the same phase – a really interesting new family of variables – "

	Faivonen glanced back and down, which was what Beedee had been hoping to forestall. The snowflakes were very close below.

	"Twenty more meters should make us relatively safe. There's a good ledge there – "

	Cold suddenly bit through the coverall. The rock seemed almost hot by contrast, and he was tempted to press against it and stop climbing. The air coming into his nose felt like fire, and he pulled his mask completely over the lower half of his face. The chill may have helped save him; he could feel the urge to breathe faster as the gas reached his blood, but the pain drove him to inhale as slowly as possible. Hyperventilation, especially in Medea's oxygen-rich atmosphere, could have cost him his physical coordination.

	There must be some mixing; he was holding on to consciousness, so there must be enough oxygen – or nearly enough; there was a curtain of darkness twisting about the edges of his field of vision. Beedee was talking again, giving very precise directions where to put his hand, and then his other hand, and then one foot, and then the other ...

	His vision cleared, and his mind slowly followed. The snow was below him again, and he could breathe without pain. He was not, however, out of trouble.

	He was on a ledge, presumably the one Beedee had mentioned, and seemed in no immediate danger of falling from it; but there was no obvious way of getting off it by any other method, either. Below, the way he had come, the cliff was climbable but bathed in the frigid gas. Above, the rock was sheer and, at first glance at least, impossible to negotiate. To his left as he faced outward, the shelf came to an end several meters short of the chimney; in the opposite direction it extended farther, but its end was quite visible.

	"Is the gas going to get this high?" he asked.

	"Not as long as it flows this way. The gas lake, I judge, is now emptying smoothly."

	"Then maybe its level will go down as it empties," the man hoped aloud.

	"Maybe. I have no basis for estimating its total volume. It seems obvious that it is fed by glaciers of alternating layers of water ice, flowing under pressure even at farside temperatures, and carbon dioxide ice, deposited in alternate seasons. No numbers are available, I fear."

	Faivonen got wearily to his feet; there seemed nothing to do but make really sure about other ways off the ledge. Fifteen minutes later he settled to the same spot with a grunt of greater weariness. No ways up, and the only ones down all led into the gas.

	"Well, Beedee, I guess I can only wish you luck. Maybe someone will come by in a few years looking for you. I just hope it isn't one of the kids."

	The machine responded only to the first sentences.

	"Perhaps you could improvise a cell to power me and keep me conscious until then. You have several metal objects in your possession, and if you strapped two pieces of different composition on my round and flat faces respectively, using a strip of leather from one of the balloons, there should be an adequate potential difference. Natural moisture in the tissue should provide electrolyte, probably to very low temperatures – it would be far from pure water. You should try before the balloons blow off the shelf."

	Faivonen had paid no attention to the half dozen of the creatures which had apparently been blown into the relatively calm area of the shelf. Even though they were big – some of them over two meters in diameter – it would have taken dozens of them to support his weight even it he had trimmed off their excess tissues and left only gas bags.

	"You do want to do a bit of gambling, then? I told you it was the spice of – let's call it existence, since you don't claim to be alive."

	"I don't see it as gambling; I am merely trying to increase my odds of remaining able to observe. You said that wasn't true gambling."

	"So it isn't. All right, I'll do my own gambling. There's a bush farther up the cliff, between us and the chimney. I have twenty meters of line, and a climbing grapnel. If I can hook to the bush, I can work across to the chimney with the rope carrying our weight."

	"I noticed the bush. It is twenty-seven meters from the nearest point on the shelf."

	"Then let's use leather, if you can call it that, from the balloons to lengthen my line."

	"I doubt that it is strong enough; lightness must be its primary quality."

	"Right. That's what I call gambling."

	He rose and approached the nearest of the balloons. It was obviously alive – the rootlike tentacles were moving, apparently aimlessly. It showed no obvious awareness of his approach, and did not react even when he stepped within reach of the tentacles and poked it experimentally with his machete. The gas bag was rather taller than his own height, thin enough to be translucent, delicately tinted pink and orange. The vital organs, if they could be called that – no one was sure if the things were animals, plants, or something entirely new – were clustered in a structure about the size of a human head at the lower end; the roots radiated from just above this, at what Faivonen couldn't help thinking as the Antarctic circle.

	If the thing were really animal in any sense, however, it seemed to be unresponsive – perhaps the cold, the man thought. Deciding it was safe, he squatted down and examined the "head" closely. The roots continued their aimless writhing.

	After close examination which told neither of them anything useful, he dissected the central mass rapidly, letting Beedee see everything he did. The organs, their shapes, and their arrangements conveyed no meaning to the man, and the machine cast no illuminating comments although its insatiable thirst for information was presumably being slaked. The balloons, Faivonen judged, must form a kingdom of their own; they showed no clear relation to other life, Medean or Terrestrial.

	The tissues of the deflated bag were as flimsy as predicted, but Faivonen began cutting strips from them. Rope making would be a long job, and time seemed limited.

	"You will have to make the cord as far overstrength as we can estimate," remarked Beedee. "It is unfortunate that we have no way to test it before completion. How long do you think you will need?"

	"Longer than we probably have. I'm hungry and thirsty now; there's little cheese; and, by that time, less water."

	"We should have started sooner, but it was impossible. I fear our lack of data has cost another human life, though I tried to avoid my earlier mistake."

	Faivonen snapped a startled question. "You mean it was a situation like this that caused Riita's death?"

	"Not exactly, though her problems involved the use of the balloons. There were human emotions involved which I had not evaluated properly, long as I had known here. She refused to kill any creatures, which could have been put to effective use, when I told her they were intelligent. I was more careful this time, fearing that you might react in the same way."

	Faivonen fought off an urge to retch. "I certainly would have. How do you know they are intelligent? Are you sure?"

	"Of course. The motion patterns of their tentacles and the changing colors of their gas bags are repetitious, and seem to correlate with their actions in rising and sinking. I have been watching relays of messages going up and down the valley from one of the creatures to the next."

	"Then they can see? We didn't find anything like eyes I this one."

	"A very interesting problem, I agree."

	Faivonen fell silent, and thought for several minutes. Then he removed and opened his shoulder pack, groped through its contents, and pulled out several pieces of metal.

	"You're giving up on your gamble?" asked the diamond.

	"Not exactly." Faivonen said no more. He selected two of the metal fragments, and cut a long strip from the gas bag, five or six centimeters wide. Then he removed the straps which held Beedee to his wrist, placed one piece of metal against its flat surface and the other on the curved one, and wrapped the skin around everything. He left the rounded ends of the machine, where its eyes and pressure senses were located, clear. Then he cut several much narrower strips and used them to tie the "bandage" in place. The package seemed secure.

	"Current flowing, Beedee?"

	"Adequately, thank you."

	"Good. I've noticed that there is a breeze at our level coming from down the valley, while the gas river is still flowing in the opposite direction. Any explanation?"

	"Certainly. The gas is siphoning – enough weight has flowed down the valley to maintain the current. The last time it got to the point where we first met the frost, and then was forced back by the tidal wind; this time it's set for the season, I judge. What we feel is the regular wind, riding over the carbon dioxide."

	"So the gas river will flow for several weeks."

	"It seems likely."

	"And I can't get away."

	"I don't see how."

	"All right." Faivonen picked up the diamond and approached another of the balloons, now shifting a little in the rising wind. With more strips of skin, he bound the package to one of the thicker tendrils, still taking pains to leave the diamond's sense organs unobstructed. Then he stood up and looked down at the glassy half-cylinder for several seconds.

	"Nothing personal," he said at last. "You put my wife in a situation which would kill her unless she changed her personality. You've done the same with me. Perhaps you aren't guilty of killing us – those human quirks you've mentioned, which are good for species survival but not for individuals, are probably doing that – but I don't choose to quibble. If my kids ever come looking for me, I don't' want them to find you."

	"The balloon won't support me." Beedee's voice was fainter, but quite audible.

	"It will support you in carbon dioxide. Try calculating which wind will carry you. I'm betting on coldside – you wanted to see it anyway." Faivonen pushed the balloon off the shelf with his foot.

	"Thank you, Elisha." The voice was much fainter, but the words could be made out. "I am coming to understand human beings. This was the action I hoped you would take. Depending on glacier speed, I should be back with your people in a few millennia – I, too, am betting on the wind towards the cold side. I seem to be winning. Of course, if these creatures have a way of coming back, I may see men sooner. I regret that you won't be there; you have been almost as interesting a property as your wife. Of course, if I do happen to get back in months instead of centuries, it would be inadvisable to have your report of my admittedly unhuman behavior waiting for me."

	The voice stopped. Faivonen watched the balloon for several minutes as it drifted slowly up the valley. Then he walked to the end of the shelf nearest the chimney, took out his rope and grapnel, and made sure the latter was firmly attached.

	Then he began climbing down.

	"But how will we do without the diamond?" Sullivan was quite frankly horrified.

	"Quite well, I should think," replied Faivonen. "We do without simpler calculators, aircraft, radios, and all sorts of other things we decided to eliminate until we could make them ourselves from local materials. This ship of yours shows we can do what has to be done. Come on – you know we couldn't afford to be dependent on anything we couldn't produce here. Beedee was left out of the original deal because he, or it, was private property, and anyway no one could decide whether he was alive or not – he might have been a citizen. Some of the younger generation have been claiming there was no use learning to read and write – Beedee would remember everything and tell us everything – that he wanted for us to believe. That, friend Sullivan, is very bad indeed, and you know it."

	"I know it, but a lot of others don't. They'll want to lynch you for losing all the knowledge of Medea we've picked up in twenty years, and they'll be right; we can't live without it."

	"They won't and they'd be wrong," said Faivonen. "In the first place I didn't lose it; most of what has been learned is either common knowledge, or has been written or remembered by someone with special interest. In the second – look, Sully: Beedee knew years ago that the balloons were intelligent, but didn't tell anyone because he foresaw it would interfere with his life style. He knew perfectly well that with the carbon dioxide river flowing one way and the air the other, the gases would be turbulent and mix at the interface – there would be oxygen enough for meters below the so-called surface of the gas river, which he wanted me to think of as the drowning line, to let me breathe and climb over to the chimney and back up again. It hurt, and was hard to keep breathing control, but I could do it and did do it. Did he tell me? No. He didn't really care whether I died there on the shelf, but he wanted to make sure I sent him off to coldside. He wants knowledge the way a baby wants milk or a teen-ager wants sex, and he's as completely selfish about the appetite as a baby or an untrained adolescent; humanity is a convenience to him, but its individual members are expendable conveniences. The key fact is that we can't trust him, and once people realize that, no one's going to want to lynch me."

	"You mean he's done this sort of thing to us before? We don't know what to believe, out of what he's recorded for us?"

	"Just that. I'd have smashed him for killing Riita, only the fact that he didn't get away or stay conscious makes me believe he made an honest mistake that time. Maybe, if he gets back early and I'm still alive and cooled off enough, I'll be able to ask him for the real details."

	"You've been calling Beedee him, instead of it. You really regard – him – as alive, don't you?"

	"Yes, As alive as I am, or you are, and potentially just as much a member of society. But what use is a liar to any society?"

The End

Isaac Asimov's Science Fiction Magazine
September-October 1978

	For several years I have been playing with the astonomical possibility, which seems to me quite a good probability, that there are numerous bodies a little too low in mass to be real stars and a little too big to be planets--if only because the old definition of planet says tht it doesn't shine by its own light. Such a microsun might last a long time, especially if it contained a reasonable amount of heavy radioactives, and warm one or more satellites even it if didn't light them very well. If such a body orbited a more normal star as Jupiter orbits Sol, interesting complications would arise for the satellites.

	When Harlan Ellison put in his emergency request for a planet with interesting details, to present ot a group of authors onstage at UCLA so that they could cook up story ideas in public, I already had a good deal of background ready, therefore.

	The sun of the system is Castor C, a red dward eclipsing binary that we already know a good deal about, and a flare star to boot (just to provide more variation). Medea is a basically Earthlike satellite of a superjovian body which I had already worked out. Locked rotation gives a side heated by Argo, the superjovian, and a cold side heated intermittently by the Castor C suns. A tilted orbit plan supplies regions of alternate permanent light and dark like Earths Arctic and Antarctic regions. I did the arithmetic on all this, and passed it on to Poul Anderson, Larry Niven, and Fred Pohl, who fleshed out my astronomy. I won't give all the details here; you'll read some of the stories which have resulted in this magazine, maybe some in others, and – eventually – all of them in a nice big book, Medea: Harlan's World, which will contain all the figures, arguments, and what have you from the UCLA meeting.

Hal Clement