Still River

Chapter Twenty Of Course I Couldn’t Know

Once again, Molly was unable to find the right words. The vision of hot food and hot bath went glimmering as it had before.

Carol happily decided, aloud, that the next thing to do was resume their trip down the river toward Enigma’s heart. It was only a matter of time before Charley made contact with them, and if for some reason the Kantrick failed, the new mappers would do the job. Five hundred certainly ought to be enough. With their armor batteries charged and the robot and its fuser standing by, there was nothing to keep them from work. Her beautiful brown fur might be sticky, matted, or even starting to fall out, but her armor would take care of any that did. She could shampoo later.

There were lots of questions to be answered. Was Enigma as spongy and cavernous as their experience was beginning to suggest, or was this something local? Were the caves really kames, and if so, were the original ice bodies that had molded them comet nuclei or something else? If they were comets, how had they incorporated themselves into Enigma’s mass without blowing up in the process, since the kinetic energy of a typical interplanetary collision is more than enough to vaporize iron? If they were comets, were there still some of them at greater depths to be found in their original state, to justify Molly’s ice hypothesis? If the basic idea was right, how had the silicates consolidated into rock hard enough to support these deep caves? Was Enigma really as young as its sun had to be? If so, how had it managed to develop highly complex life forms? Was biochemistry really the answer to the air-circulation problem? Was it also the answer to the problem of why the little world had air at all—their originally assigned research question? It could be; if gas precipitated as solid before getting far from the surface, it could hardly escape.

Even Molly, thinking all this over, was able to forget her personal discomfort and join in the planning. Clearly, they had to go deeper. However good Joe’s new little robots might be, they would not be able to select biological specimens for detailed analysis; researchers would have to do that themselves. Furthermore, geochemical data were badly needed, too; the lasers and picks would have to be put to more use.

Perhaps it was no longer really essential to follow the river, as there was now another way for the others to find them and get the group back together; but since they were now frankly seeking for a route down, the river seemed the obvious guide. Also, it would clearly be much easier for even the new robots to find rivers than explorers.

With the anxiety about the robot allayed and the collecting can of ammonia water poured gratefully out on the rock where the machine had stood so long, Molly and Carol resumed their journey.

Charley, too, was following a river—Jenny’s—but there was so far no evidence that it was either the same one as Molly and Carol’s or one of its tributaries. He, too, was finding much life. His verbal descriptions irritated Carol; the organisms were either decidedly different in structure from those she and Molly had been seeing, or he was doing a very poor job of describing. He was collecting specimens, of course, so there was no point in being critical until these could be examined, and the Shervah managed to restrain herself.

Time went on, on the whole happily. Everyone but Jenny got deeper into the planet, though for Joe it was by proxy; he remained at the antarctic surface, finding and charting more and more wind-caves and sending a small swarm of mapping robots into each as he found it. The halo of fist-sized cylinders that accompanied his own craft was growing smaller, though replacements were still homing in on him from the boat’s shop.

Even Carol and Molly were finding a gradual change in the life forms around them, though not enough, the former insisted, to account for the discrepancies in Charley’s descriptions. The temperature was rising significantly, though their armor prevented them from noticing the fact through their own senses. The real warning was the appearance on the rock around them of a faint, white mold.

Even Carol had reached the point where not every life form had to be examined closely, and neither had a container left in which to collect anything new, but this stuff got thicker as they progressed, and finally both felt that it deserved detailed attention. Molly scraped some from a convenient surface and spread it on her palm where they could both look at it. They saw a mass of needlelike crystals matted in a way that reminded the Human of the sparkling stuff she had seen in the first cavern.

This, however, was glassy rather than metallic. There was something else familiar about it, and as the women watched, the mass abruptly lost most of its whiteness and then slumped into a tiny puddle of liquid on the palm of Molly’s glove. She didn’t feel the local heat loss, as her suit had very efficient distributing apparatus even at the thin gloves, but what had happened was suddenly plain enough.

“Frost! Water!” the Human exclaimed. “What became of the ammonia? What’s the river made of now?”

The river at the moment was a dozen meters away from the parked robot. Carol headed for it, eagerly but with caution bred by the low gravity, took a sample, and made the same standard test she had used on the stream so far above.

“It’s not pure ammonia by a lot,” she reported after a moment. “This gadget makes it about seventy percent. I don’t know what the rest is.”

Molly’s armor lacked comparable testing gear, but she had a thermometer probe. She dipped this into the liquid on her glove and held it away from her suit, watching sample and reading as the substance froze again.

“Just under two seventy-two. Not pure, but mostly water. What’s going on here?”

“What’s the air temperature?” asked Charley.

“Wait a moment—it’s still dropping, now the stuff’s all frozen.” Charley waited, to Carol’s surprise. “About two sixty-four. Check, Carrie?”

“That’s what mine’s been saying.”

“And the river?” Another brief delay while the women made the test.

“About two fifty-five. Much too high for pure ammonia, much too low for water. I couldn’t begin to calculate percentage composition because it’s probably not an equilibrium mixture, I don’t know the constants for either association or ionization in those mixtures, and I certainly don’t know what else may be there. So what’s going on?”

“Very simple,” said Charley. Carol rolled her eyes wildly but managed to keep silent. “There’s heat below, warming the wind that comes up. Liquid is going down. The walls of the caves and passages connecting them give plenty of surface area and are rough enough for all sorts of turbulence. The planet is a countercurrent heat exchanger…”

“Better yet, it’s a reflux condenser!” Molly jumped enthusiastically at the suggestion. Carol, with her conditioned skepticism for Charley-hypotheses, remained silent. “But there goes the last chance of my finding any ice—even water ice—down below. Wouldn’t you say, Joe?”

“I gather you just found some.”

“You know what I mean. Masses of it. Chunks that would explain these caves being kames, not just frost deposits on cold rock from vapor picked up from the river.”

“I’m afraid so. I can’t yet guess how far down the caverns extend, and I don’t know how far down you are. My new robots have mapped downward a little over a hundred and fifty kilometers, but they’re not equipped to take pictures or specimens, and I regret to say they can’t measure temperature.”

“Joe!” Molly hoped that Carol’s shocked tone was not meant seriously. The Nethneen seemed unaffected; at least, he offered no further apology.

“To that depth,” he went on, “the crust remains about the same. Between a quarter and a third of its volume is open space, as measured by the radar of the small units.”

“How do you keep in touch with them for such a distance through rock?” Molly asked.

“I’ve programmed them to spread out in such a way as to be able to relay among themselves and all the way back to me. After the whole set of robots is completed and extended as far as practical, I’m going to have to go underground myself so that they won’t have to use so many units in relay to the surface that their mapping front is too greatly reduced.”

“So they each carry complete diagrams of the volume covered, and so does your own carrier.”

“Right. I’ll be able to follow down very quickly, when the time comes.”

“Fine,” said Molly happily. “Then downward to the warmth of the Underworld. This is starting to be fun. Oh—Carol, how about your armor’s refrigerator? Is it all right? Is there any reason to worry about it? What sort of backup does it have?”

“It’ll work. Standard equipment. No moving parts bigger than electrons to get out of order; I never heard of one failing. And I do wish you’d never given that word worry to my translator. Come along, and even if you can’t help worrying about yourself, stop fretting over me.”

Molly made no answer, though she wondered whether Carol or her own translator had come up with “fret”. She came along.

No one had bothered Jenny for a long time. Joe would not have dreamed of it, since she was presumably working; Molly would not have as long as Joe might notice; Carol had managed to resist by reminding herself that any questions would have made her look too much like Charley; what had held the Kantrick back no one wanted to ask.

When the Rimmore finally did speak, Carol immediately keyed the robot to a stop; she wanted to give full attention.

“There’s obviously a lot yet to check” came the grating tones, “but you’ll all want to hear this much right away. The organisms I picked up represent at least two basically different life forms—that is, different in genetic coding. They are cellular in structure, which is not surprising, since that is the easiest way to engineer the nutrition-in and waste-out problem for any creature above microscopic size. The interesting point is that they do contain high energy compounds, as was suggested. There are hydrazine and hydrazine derivatives in all of them, nitrates in some, hydrogen peroxide in others with some overlap, and azides in a few. One had so much hydrazoic acid I’m a little surprised I’m not scattered around the cavern where I found it, so watch yourselves, all of you.”

Carol reacted gleefully. “The next step is to find how they make the compounds. The primary energy source practically has to be the sun, but…”

“It’s getting hotter as you go down,” Charley interjected. Carol was silenced for a moment.

Molly decided to play safe, and made the obvious answer. “Another point to check as we go. I wonder how hot it will really get. Even in this gravity, there must be a limit before the rock creeps and these caverns close.”

“Well, it’s a young planet, we’ve been assuming. Maybe the creeping is still going on.” Molly looked uneasily at the sections of cavern wall that her light and Carol’s allowed them to see.

“I’m not sure I really like that thought. If you must dwell on it in conversation, please stress the word creep. Anyway, we’ll look for more life, now that the liquid has changed to water. Things certainly ought to be different.”

“But it isn’t all water,” Carol reminded her. “Ammonia from above is still mixing with it—which I suppose contributes to some of the heating that’s been worrying us. The pure water has been vapor, condensing on cold walls.”

“Right. Right. But do you know any life forms that operate anywhere near fifty-fifty ammonia-water mix? All I’ve ever heard of are either one or the other, with the one not the main solvent usually quite poisonous in more than trace amounts. My own body produces ammonia, but I have a couple of very complex organs we call kidneys whose main job is to get rid of it and some chemical machinery to turn it into something less toxic until they do. There are plants, if they are plants, growing in that river, Carrie. Are they water-based with evolutionary provision to avoid the ammonia, like me, or the other way around, or what?”

“Collect them. We’ll see.” Carol actually examined her own carefully labeled cans, selected one, discarded its contents, and replaced it with material from the river. She re-sealed the cover and redid the label, looking almost defiantly at Molly with one eye as she did so.

The Human said nothing to the implied challenge, but after a moment remarked, “We’ll be back, you know.”

“I know. Specific answers are more interesting than general ones, though.” The giant had to agree, at least for the moment. They remounted the robot, and continued down river and through caves, sometimes more or less horizontally, quite often chasing another fall from top to bottom—much more cautiously now. They had less to go on but were inclined to agree with Joe’s estimate that a quarter to a third of Enigma’s volume was open. At the thought of the increasing thickness of planet above, Molly found herself less and less resentful of the negligible gravity. Maybe it was just as well that the rock didn’t weigh much.

Wherever enough wall area could be seen, she checked carefully for evidence of faulting, hoping it would not appear. Sometimes she went to the length of sweeping mud out of the way to get a better look at underlying rock. She kept reminding herself that some of the laboratories on Think were over two hundred kilometers below the surface, and Think was an ice body, presumably less rigid than Enigma’s silicate structure, and unless the hollows weakened the latter ...

She put that possibility out of her mind, firmly. After all, Enigma had presumably had a million years or so to collapse in, if it were going to do any such thing; why should it pick the moment she was visiting the place?

“The last of the little mappers has arrived,” Joe finally reported. “I’m going underground to get as wide a search front as I can. Things aren’t going quite as fast as I hoped; apparently my machines aren’t spreading out as widely as I had planned. Don’t worry, though, the diagram is growing fast enough, and if it seems to slow too much, I’ll come out and hit the planet from your end.”

“I wasn’t worrying, and I’m sure Carol wasn’t,” replied Molly. “Keep your eye open for life forms; we’ll want to compare the two hemispheres.”

“Certainly. I have entered a cave that, according to my recorded diagram, provides a relatively quick path to the lowest level my machines have reached so far. I have seen no living organisms yet but am keeping lights on all around me. I’ve set my controller to follow the passage recorded and can devote full attention to observing. I will report anything worthy of note.”

Joe fell silent, and routine supervened. Molly, supposedly looking out for noteworthy material, was letting her mind wander once more; she was wondering who would be next to break the silence and trying to decide whether Charley deserved odds if she were to bet on the point. She hoped partly that it would be Jenny, with more details about the local life chemistry, and partly that it would be Joe.

She was also keeping rather close watch on her thermometer, since another thought had occurred to her. The local air was now well above the melting point of ice, but the last check had shown the river still to be somewhat below that temperature; it was evidently not yet pure water.

It was Joe who won, perhaps half an hour after he had started underground.

“There’s something strange about my diagram,” he reported. “It seems to be growing narrower at the lower end, as though the machines were finding fewer and fewer ways to go, and those were all funneling closer together. I find that both surprising and disturbing.”

“So do I,” admitted Molly. “If only the polar regions are porous, you’ll really have to go back out and come for us the other way.”

“And it will be necessary to rethink our ideas about planetary air circulation from the beginning. I shall investigate in person, of course, before committing us to any premature conclusions.”

“Of course.” Molly hoped she had kept sarcasm out of her voice; if she had not, she was sure now that the Nethneen would spot it. She maintained silence for more minutes, wondering what Joe’s investigation would disclose.

“This is a bit embarrassing,” the quiet voice resumed at length. “There seems to be no real change in the planetary structure. I made another thoughtless mistake in programming.”

“Do you care to be specific?” Molly wasn’t sure she should have asked even that much, but couldn’t resist.

“Of course; it will serve as a warning for all. I had, of course, equipped the machines to detect and home to free metal, since the search for you and your robot carries high priority.”

“Of course. That seems perfectly reasonable so far.”

“True. My mistake was in failing to provide for shutting off all the other metal sensors when one had responded. It appears that one of the machines has found a metal object, and all are now converging on it. I regret to admit that I am going to have to reset them individually when I get there. This will take some little time; I trust you will forgive me.”

“It seems a natural mistake. I wonder what metal they found? Offhand, I see no reason for there being anything of the sort—how far?—two hundred, nearly three hundred kilometers below Enigma’s surface.” Molly was not just being polite; even she was more curious about the discovery than amused or resentful at the Nethneen’s planning slip. Not even Charley sounded superior as all chimed in with comforting remarks.

“I will certainly examine what they have found, but will be some time getting to it. I suspect the approaching passages will be somewhat clogged with my robots.”

“Maybe it will be in a cave.”

“Maybe. I will let you know. I assume you are still traveling.”

“Yes. Nothing to report. You, too, Charley?”

“Nothing much. My river has joined a larger one; I am continuing to follow downstream.” None of them asked Jenny, presumably busy in her laboratory.

It was more than two hours before Joe reported again.

“It is in an open cave, but my machines are so clustered around whatever they found that I can’t see it yet.”

“Maybe it’s just as well they didn’t find us,” Carol remarked.

“Oh, they can’t be in actual contact; they were set to stop a few meters away and keep reporting position. I’ll have to reset a lot of them before I can see what’s there, though; if I merely push them out of the way, they go back as close as they can without interfering with each other. I’m starting to work now. Five or ten seconds will be enough on each—I’ll simply turn off the metal search.”

With five hundred—but he won’t have to do all of them before getting to the middle of the pile, Molly thought. Well, we’ve waited longer before. She kept the thought to herself; there are times when ordinary courtesy goes in line with mere decency.

The minutes passed, and the women resolutely kept their eyes and minds on the passing scenes revealed by their lights. There was still vegetation, if that’s what it really was. Neither of them had seen anything resembling animal life, in the sense that it could move around under its own power. Bushlike, grasslike, and totally strange growths showed both beside the river and in it. Again they stopped to check liquid temperature and, as far as they could, composition. It seemed fairly certain that the water percentage was now nearly total; there was nothing obvious to tell what the plants were doing about this. There was no point in collecting anything else; they would have had to discard something else, probably just as informative. They went on.

Then Joe’s voice sounded, with the near-whisper that indicated use of the private channel.

“Carol! Molly! There is a problem here. I am not sure what I should—no, I’ll have to face it and solve it myself.” He shifted to the general translator channel.

“I’ve found what attacked the robots, and it is a little disconcerting.” He paused, long enough for Charley to get in his inevitable question.

“What is it?”

“It seems to be two suits of environmental armor, designed for different species. One I do not recognize by name, though I have seen members at the School. The other, while its design is not just like any I have ever seen, would fit a Kantrick. You could get into it, Charley, except for one fact.”

“What’s that?”

“It is already occupied, I regret to report.”

“You mean there’s a—a…” Charley produced a choking sound that Molly had never heard from him. Before she could begin to speculate on what her translator was doing, and what sort of signal her fellow student was actually putting out, Joe responded.

“Yes, I mean there are remains of the original occupants in both suits. I am not a good historian, but would guess from some of the more obvious engineering features of the armor that they have been here for perhaps a thousand years.”

The stammering that had afflicted the Kantrick for a moment disappeared. “Have you examined them closely?” “Not very, and only by eye.”

“What’s left of the bodies? Can you tell how they died?”

“Very little is left. The Kantrick’s exoskeleton is there; soft parts such as eyes are not. The armor apparently remained functional long enough for biodegrading reactions to go well toward normal completion. The other being appears to have had a hard endoskeleton like Carol, Molly, and Jenny, and tissue seems to have shrunk around it. That may not be accurate; as I say, I am not really familiar with the species in question. The armor has no visible damage, and I would guess they died of chemical deprivation—suffocation, hunger, or thirst. What we feared was going to happen to Carol and Molly, before they managed to revive their robot. A power connection links the suits, which suggests that the two shared what resources they had as long as there were any. I would like to believe that, certainly.”

“Any sign of how they got there?”

“None. None that I recognize, at least.”

Charley was silent for perhaps half a minute. Lor the first time, Carol seemed to have had her emotional armor pierced; she was clutching Molly’s arm tightly and breathing hard. The giant slipped her other arm around the small form and held her as close as their armor allowed. Molly herself had been afraid all along, but more afraid to admit it; the silence and darkness of Enigma’s caverns, coupled with the knowledge that nothing there would supply her with usable food or safe drink, had haunted the edges of her mind from the time she had gone underground. She had envied Carol’s ability to ignore the dangers, or inability to face up to them, whichever it was. Now the envy was gone, with real sympathy taking its place.

Well as the two knew each other, Molly realized that their attitudes toward death were still hidden. She knew nothing whatever of the customs or religious beliefs of a single one of the School species, not even the Nethneen. It occurred to her that in an institution of several tens of thousands of beings, most of them as far as she had heard with life spans comparable to the Human one, there must have been numerous deaths since she and Rovor had arrived; but she had not been aware of a single one of them. Some aspect of Joe’s excessive privacy-consciousness? She couldn’t even guess; and she could not really tell how the Kantrick was reacting to the word of what appeared to be the death of one of his own people.

Charley’s voice caught their attention again, and the Shervah released her grip on Molly. The Human kept her arm around the other as they listened.

“Is there any record of students being lost doing lab work here?”

“None that I know of.”

“Molly, do you know?”

“Of course I don’t. How could I? I’m among the first of my people ever to attend this institution; there hasn’t been a human being in this part of the galaxy until a very few years ago. You said yourself the planet had been used as a student lab for thousands. I should think you’d know if anyone does, Charley. You kept telling us about earlier student results being sealed or destroyed so that the lab work could be done over by new classes, but it seems unlikely to me that accident reports would get the same disposal.”

“Then you honestly don’t know.”

“I really and truly don’t.”

There were several more seconds of silence from the Kantrick. When he did speak, it was very slowly, and on private channel to Molly.

“I should have guessed.”