Still River

Chapter Eighteen Of Course There’s Inflow

“I don’t think I can take the temperature,” the Shervah explained. “I waded in that first brook for a while, and my feet were freezing even through the armor. If temperature gets too low, my air starts to condense.”

“That’s right; nitrosyl chloride has an awfully steep vapor pressure curve. Ail right, we’ll have to find shore somehow, or think of a way to dry out the inside of the robot and get it going again while we’re still swimming—that doesn’t seem awfully practical, somehow. But wait a minute—the temperature is a lot colder for me than for you, and your armor should insulate as well as mine. I’m perfectly comfortable—well, as far as that’s concerned, anyway. I’d give a lot to get out of this suit and wallow in hot water. Are you really getting cold?”

“Not yet. I’m reporting what happened earlier. My feet nearly froze while I was wading.”

“Did you measure the actual temperature of the brook?” “No.”

“Then the temperature of this puddle won’t tell us whether you’re really in trouble, but we’d better get it on general principles.”

Molly was somewhat mystified by the situation. As she had said, the ambient temperature was much worse for Human than for Shervah, and the small humanoid’s suit protection should be at least as good as Molly’s. Indeed, it must be; a vivid picture from fairly recent memory and more recent conversation preempted her thoughts for a moment. It was of a black, airless sky, dominated by half a dozen blazing O-type suns all within three or four parsecs. Much less impressive, though bright by Solar system standards at some seven hundred astronomical units, hung Fire and Smoke, the binary dwarves that formed the main mass of the School planetary system. None of their individual planets was noticeable at this distance. The foreground was a landscape of grayish, dirty methane ice, like the surface of Pluto. Molly and Carol had been together, just as they were now, with an assigned experiment. They had just reached Sink, the outermost common planet of the School suns, with its ten-Kelvin environment that was needed for their work, and this time it had been Molly who was uneasy. “Come on!” Carol had been saying. “It’s safe enough. There’s no gas to conduct; you can only lose heat to the ground, and there isn’t much contact area even for you. Don’t worry; I’ve been here before!”

Here on Enigma they did not have vacuum around them; maybe that made the difference in the Shervah’s mind. Molly would have to be the support.

She attempted to bring her set of wrist instruments in front of her helmet while swimming hard enough to keep from being sunk any further by the robot. She was not very successful and was a couple of meters below the surface by the time she had a reading. Its value surprised her enough to take all her attention, and the two went down even further as she called the others.

“Joe! Charley! The temperature is up about ten Kelvins from the value I reported in that upper cavern. Either we’ve come down an awfully long way, or something is carrying heat to this liquid. Do you check with that, Carrie?”

“Yes. I still don’t know whether it’s warm enough so I can stop worrying, though.”

“I’d think you’d be feeling cold already if your armor’s heaters weren’t handling the situation. I know ammonia doesn’t have the heat capacity of water, but…”

“But if this were liquid water, I wouldn’t be worried about the cold.”

“Is your armor refrigerating or heating right now?” “Heating.”

“Which was it doing when you were freezing your feet?”

“I don’t remember—didn’t notice. I suppose it was heating, but now that I think of it, maybe it was just trying to hold an average. I don’t know much about its heat distribution system or its internal sensing…”

“You should have made the armor yourself,” pointed out Charley. Carol, for once, had no answer; the criticism was completely right, and she knew it. The suit was part of her field equipment, and she should have known all there was to be known about it.

“Tell the rest of us if you feel the slightest bit cold or your air pressure seems to be dropping,” advised Molly. “We’ll look for dry land, but maybe we needn’t be as frantic about it as we thought. Let’s get back to the surface and try to see if we’re getting anywhere.”

But the surface came back to them. They might have been falling for several seconds—perhaps half a minute—before either of them realized that surface was all around them; they were once more inside a large drop rather than a whole river. They must have gone over another fall. Molly reported the fact, resignedly, to the three so far above.

“We’re trying to swim out of it, but the stuff is wet and sticks to us. It’s huge, too—the biggest by far of any we’ve seen yet.”

“Are your heads through the surface so you can see out?” asked Joe.

“We’re sticking out,” Carol replied, “but there’s too much stuff on our helmets to let us see. Why is it important? There’d be nothing but more drops of river floating down around us.”

“Different size drops, and different density objects like you and the robot, should fall at different rates—there is air, remember. I was wondering whether you were in front of most of the stream or behind it.”

“I don’t see how we could be anywhere but middle” was Molly’s contribution. “What we need is to get to one side and dry out this piece of hardware. That’s worth the effort of getting out of the drop for, though. Come on, Carrie—we’ll give some momentum to the robot as long as it’s in the liquid, and as it’s about to emerge we’ll try to get out ourselves. With luck, we’ll be clear long enough for me to dry off your helmet again, and you’ll have a chance to tell whether there is any direction that will get us clear of this stuff. I suppose we’re in another cave.”

“That’s what I was taking for granted,” agreed Joe.

“All right.” Charley was practically authoritative. “You two try to get dry, and Jenny and I will get back to mapping. Now we look for any river, I’d say, and follow it down. Sooner or later we get to the same lake, or ocean, or something.”

“One more delay,” Joe said firmly.

“What?” grated the Rimmore.

“One more piece of apparatus for your mappers, and never mind remarks about whether I should have thought of it earlier. Come back here while we install radar units in your machines. Right now you have to explore any cavern you find visually and might still miss some connecting passages. This way you’ll get every open space you enter, logged in detail the moment you’re into it, and your computers will maintain a complete three-dimensional image set that you can display for your own convenience to help you see where you’ve been, how to get back, or where other things are—if you get a broad enough total picture. Head back here; I’ll have the units ready for you when you arrive.”

Not even Charley argued.

Twenty hours later, Molly woke. There had been no particular stimulus; there was still darkness except for her lights and Carol’s, and at the moment not even translator voices. They were far enough from the river, for the moment, so that it was nearly inaudible, not that it made much noise anyway. The hours they had spent trying to win free of the falling drops when they were falling and to work their way out of eddies and other currents when they were flowing had been the main reason she had had to sleep. They had finally struggled to the bank at a point where the stream was practically horizontal, and carried themselves and the robot far enough from the weirdly writhing current to feel safe from it; there, even Carol had collapsed. The Shervah was still lying motionless; for the first time in Molly’s recollection, her eyes were actually closed. For a moment the Human heart almost stopped as she missed the robot; then she saw it parked on the rock a couple of meters away. Was it dry yet and the energy converter that was their life usable?

Probably not, since the control access port was still closed. They had gone to sleep without unsealing it, she realized. Molly muttered something under her breath that she would not have said in Buzz’ hearing, went over to the machine, and got it open. Whether the surrounding air was far enough below saturation to do them any good could not be checked by any of her armor’s instruments, but at least it could now circulate inside the device. There was a fairly strong breeze; the feathery growths that had caught the Shervah’s attention before she had remembered about the robot, and caused her to unfasten her safety line and leave Molly to carry the machine unaided the last few meters, were nodding and waving as the air moved by them. Carol had not had time for much of an examination; like her companion, she had been too exhausted and had fallen asleep even before reporting the new life form to the others. Molly had refastened the rope to her small friend’s armor, stated only that they were ashore and perhaps drying off, and lost consciousness herself. She had made several thirty-kilometer swims, in reasonably warm water, in her time; she had twice done hundred-kilometer hikes carrying cooking and shelter equipment under the three-quarters-normal gravity of New Pembroke; but she had never in her life felt as exhausted as when she and Carol had emerged from the river. Armor made a difference that low gravity could not offset.

Sure that Carol’s translator would not let anything but vital messages through as long as she needed sleep, Molly reported the present situation, including the new life, to the other students. A close look, taken at Jenny’s insistence, revealed that there were several different organisms, or at least several different shapes. She tried to make sense out of their engineering, but had no real success. There were waving fronds, evidently maximum-area organs; they could hardly be intended to intercept light, like the leaves they resembled. Rootlike bases proved not to be roots—not only did they fail to penetrate the rock, they did not even cling to it. The things could be picked up easily and set down elsewhere without obvious effect. The “roots” hung limply even in Enigma’s gravity during the transfer, and made no effort to rearrange themselves when the organism was put down again. The stemlike parts connecting roots and fronds did bend back and forth, without apparent aid from the wind, both while they were being held and while they were standing where she first saw them. None of it made sense to the Human. She reported as much.

Joe was unusually silent, even for him. The confirmation of highly organized life on Enigma had been hard for him to accept. However firmly an intelligent being may claim that it bows to facts, no mind accepts casually the readjustment of its basic beliefs; and Enigma had to be too young for this. Life might conceivably have gotten started—this seems to happen pretty early in the existence of most planets—but it could not by any recognized process have evolved so far in the time available. He badly wanted some of these organisms in Jenny’s lab; they needed detailed explaining.

Molly’s troubles, and later Molly’s report, had done something Joe’s work on the mapping robots had never managed to do; it had driven his wind-charting project entirely out of his mind for a time. With Charley and Jenny back underground busily but slowly building a three-dimensional diagram of the sponge that was Enigma’s crust, Joe would ordinarily have been standing in the tent in front of his display to see how the wind map was getting on. Instead, he stood motionless in the boat’s conning room before the controls, buried in thought, but doing nothing.

Even Carol’s more detailed information, when she finally woke up and began to study the organisms, took little of the Nethneen’s attention. He was already convinced of the facts and needed more details than Carol could supply to make them fit his ideas properly. The Shervah’s deepish voice alternating with Rimmore gratings—or Joe’s translator’s equivalents for these identifying qualities—were merely background symbols, not information. It took a direct call from Molly to bring him out of the trance.

“Joe! I suppose you’re back at your maps. Don’t they make sense yet? It will be nice to hear about something that does!”

“Sorry, Molly. I was allowing myself to get distracted, I’m afraid. I’m not in the tent. I’ll let you know as soon as possible what’s developed.”

The small being headed for the shop, however, not the tent.

Molly was too versed in Nethneen courtesy to pursue the matter until Joe chose to continue it. She turned her attention back to their local problem.

“Do you think this machine is going to dry out in any decent time, Carrie?” she asked.

The Shervah had not given the robot a thought since she had awakened; the vegetation, if that’s what it was, was much more interesting. She looked up with one eye and thought for a moment.

“I suppose so,” she said. “The rock seems to be dry enough. Maybe you should sit on it, or lean against it, to provide a bit more heat from your armor and speed up the process, if you can bear to stay away from these things. They don’t look a bit like the ones I saw up above.”

“Or the metal whiskers I told you about, which are just as likely to have been alive, I’d say now. Of course we’re a lot deeper, and it’s a lot warmer, and there might be a whole different ecology. It’s a pity we can’t stay here long enough to study it carefully.”

“Why can’t we?” asked Carol in surprise.

“Because the moment this robot dries out, we’ve got to drive it along the river in the hope of meeting the others. If we don’t make contact with some part of this rock sponge that they have mapped, none of the beautiful specimens you’re collecting there will ever get to a lab. We may be able to come back, and I’m as curious as you are, but I want to keep on living, too. Come on, little friend, be sensible.”

“I suppose you’re right. All right, you turn your heat exhaust on the robot; I’ll keep working on these things and collecting what seems best, while you get the machine dried out. All right?”

“All right. But I suspect your armor is using its refrigerator now, too, isn’t it?”

“Well, yes; but yours is a lot bigger and working a lot harder with all the heat you generate. Find out from Charley and Jenny whether they’ve found any more quick ways down like ours.”

“There was one, I thought” came Charley’s voice. “It was a really terrific wind; but it led to a passage too narrow for my mapper. I didn’t report it because I didn’t want to disappoint you. I’m still going down wherever there’s a choice, and so is Jenny; and we’re working our way south.”

“Which may not be the right direction any more,” Molly couldn’t help remarking.

“Maybe, but we have nothing else to go by. After all, we needn’t worry; a lot of this planet seems to be open space, and the radars do a cavern very quickly. If it keeps the same average, we should be able to map the whole volume in barely two thirds of a million years—a good deal less if Joe will build another robot and join us.” Charley’s dead-pan remark completely silenced even Carol for a moment, and before cither she or Molly could think of anything to say, the Kantrick went on. “The real need, of course, is another river to follow down. The farther down, the fewer the branches, one would expect. I’m getting more and more convinced there must be a sort of ocean somewhere below, and your river and any other must lead to it. If nothing else, working our way in what was your direction should get us to your river or one of its tributaries.”

“That seems reasonable,” admitted Molly.

“In that case,” Carol pointed out promptly, “we might as well stay right here, as we wanted to do awhile earlier, and let them catch up with us.”

“Two minor objections,” replied her big friend. “They might not encounter the same river, and there should be more of this ecology to be seen as we keep going.” Carol was silent but made a hand gesture of agreement. Molly, too, forbore to pursue the subject further; she did not want to admit how much more the first of the two points now meant to her. Not, at least, in Joe’s hearing, and of course it would be going out of her way to shift to private channel just to make the remark to Carol.

The Nethneen’s voice sounded on top of her thought of him.

“Molly, I don’t suppose your robot’s power is on yet. About how much time do you two have left in your batteries?”

“I’m about eighty hours,” Molly replied promptly—she had no need to look at her gauges for that information. “Carol’s batteries carry more energy, but her size gives her a poorer surface-to-volume ratio than mine, and she must have had to use more on temperature control. How about it, Carrie?”

The smaller woman had no need to look, either.

“About ten hours less than you. I’m taking it easy on eating until we can charge up again.”

The Nethneen spoke thoughtfully. “It might be a good idea for me to join the underground mapping. It won’t take long to finish another machine; I started the parts on automatic down in the shop as soon as I finished the radars for Charley and Jenny.”

“You mean you aren’t back at your map yet?” Molly asked with mock severity.

“I have just reached the tent for a quick look—I suppose the data might be useful, even in the present emergency ...” His voice trailed off; none of the others could even guess what he was thinking.

“For Pete’s sake—if that doesn’t translate, never mind—get into the tent and look your own work over.” Molly was not entirely mocking. “We’ve been guided by air currents most of the time since we’ve gone underground. We haven’t the faintest idea what the rules about wind are on this silly world, except that there’s something peculiar about them—Jenny found out before we got here that the high ones were circulating toward the summer pole, which I at least would expect the surface currents to be doing instead. Stay there for a few hours and see if you can figure out enough of the pattern to make a real guide for us. Rivers have their good points, but this one seems to be taking us toward the middle of the planet, and there’s a limit to how far I want to go in that direction. Get to your map and think!”

The Human caught her breath and blushed; she hadn’t meant to get so intense, and just what Joe did probably wouldn’t make that much difference. Maybe nothing would. Was she, Mary Warrender Chmenici, getting panicky? Thoughts of Rovor, and Buzz, and planets where one could walk around without armor, and even swim or sleep outdoors, went flashing through her mind; she suppressed them sternly. Reality right now was Enigma.

“All right, Molly.” Joe’s voice was as quiet as ever; she couldn’t tell how much he had read of her feelings. “I’ll let you know how the map is doing; you can help in the analysis, perhaps. I’ll be in the tent in a few seconds, but will no doubt be longer working up a meaningful description for you.”

Carol looked at her huge friend curiously, but decided to say nothing. No doubt the Human would explain the thought behind her outburst in good time. The Shervah, with a real research problem holding her attention, was genuinely unable to get her mind onto the fact that she was in actual physical danger—though the suggestion that her mind was at all similar to Charley’s would have been taken as a serious insult.

Molly, more aware of the danger than of anything else but quite ashamed of the fact, deliberately turned her attention to the robot. Carol might not have been serious when she suggested that the heat from the Human’s armor might help dry the machine out, but the point seemed well taken anyway. She was beginning to wish that her heat pump exhausted almost anywhere except between her shoulders; she had used it so often as a tool lately that the problem of aiming its microwave beam was becoming a major nuisance. She seated herself, most uncomfortably, on the field disc of the robot in front of its control access port and bent forward as sharply as the armor itself permitted. She was reminded emphatically of a lab exercise she had had to do in crystallography, involving some hours of looking into a microgoniometer, the week before Buzz’ birth. She couldn’t see whether she was really throwing heat into the open port; she wasn’t contortionist enough to see the port itself, or enough of a cold-worlder to detect the beam with her own senses. She comforted herself with the thought that the radiation had to be striking some part of the machine and producing at least a little effect.

“Carol,” she remarked, very carefully on private channel, “I’ve just thought of another attachment for the next robot design. They should have internal heaters to dry them out automatically.”

“I don’t think even Charley would have suggested that seriously,” the Shervah replied.

“I certainly hope not. You know, little friend, your suit must be refrigerating much more enthusiastically than mine at this point; the environment is really hot for you. Wouldn’t you do as much, or more, good than I here—quite aside from the fact that you’d fit better?”

“Maybe. Let me finish checking out this stuff here, and I’ll spell you.”

Molly forbore to ask how long the checking out might take and settled herself for an indefinite wait. She never knew how long she sat there, but was not too surprised that it was not Carol who brought the session to an end.

“Molly, I have a problem.” It was Joe’s voice, calm as ever.

“With your map? Isn’t it growing properly?”

“Very nicely, but very unexpectedly. Your remark that winds aloft were traveling from winter to summer pole, and that this surprised you, was what I checked first; the upperlevel robots seem to be agreeing with you. Naturally I assumed that the surface circulation would be in the opposite direction, but the lower-level machines don’t agree. Except for minor deflection one would expect from inertial effects—the rotation is slow, but Enigma does rotate—the air at all levels is going from winter to summer hemisphere.”

“Then the return circulation must be underground—that must be the wind pattern we need for guidance!”

“No, Molly. Think. The air is coming out of every cave in your area that you, or Charley, or Jenny have found—there was even some coming up through the sand where Carol was trapped, and that was all in the summer hemisphere. Where does it come from?”

“And where does it go? You need a sink as well as a source!”

“Precisely. I think I have an answer to the sink, but not to the source question—or rather, I think that Jenny provided us with the sink answer.”

“How?” grated the chemist. Molly simply waited for an answer. She was not surprised that Joe had one; he would probably not have mentioned the question until he did.

“You told us, when we first arrived, that a lot of the dust in the air was ammonium carbamate, which you would expect to form from ammonia and carbon dioxide since the two are quite unstable with respect to each other. The dust is solid and takes up far less room than the gas. If it forms primarily at the summer pole, it is using up gas and dropping the local pressure at all altitudes. The drop in volume would far more than offset the rise in temperature from the reaction heat.”

“And why would it form primarily at the summer pole?” asked Jenny.

“I would suggest that Arc’s radiation is supplying the activation energy for the reaction. I don’t know how big that is, offhand, but carbon dioxide is stable enough so that a reasonably large kick must be needed.”

“I agree,” said the Rimmore at once. “I don’t have the actual value in my head, either, but your point is a good one.”

“All right, I see that, but where does the gas come from?” No one was surprised that the question came from Charley, but for once no one blamed him—not even Carol, who had been on the point of asking it herself.

“I can think of two possibilities,” Joe replied, much more slowly. “I’m afraid I don’t like either one very much, but—well, here they are. One is that Molly’s ice, which made the kames you folks are exploring, is still below in large quantities and is still boiling out of the planet.”

“And the other? " Carol thought she knew what was coming. She was right.

“The other is that your life forms are returning the gases to circulation, seasonally or constantly.”

“Then we were wrong to go upwind; there are no inbound currents anywhere on the planet!” exclaimed Molly.

“I wouldn’t say that. It’s a quantitative question. Huge masses of atmosphere travel from winter to summer hemisphere; it seems quite possible that some of it goes below the surface.”

“Of course! There must be inward currents at the winter pole!” cried Charley.

“You make my hearts leap out of time,” Carol said, in a tone that needed no translation. “There’s no ’must be’ about it!”

“If my numbers are right, so is Charley,” Joe’s went on calmly. Carol silently came over to Molly and began to help heat the robot.

Molly wondered whether she could blush under her fur.