Still River

by Hal Clement

  “Did the stream go perfectly straight for twelve meters, with a width varying from ninety-three to one hundred centimeters, then make a five-degree bend to the right, widening by twelve centimeters as it did so, and then take on a rather sinuous path for the next forty-five meters, making three oscillations with an amplitude of just under one meter, and…”

  “As nearly as I can recall, that’s about right; but I can’t be sure how much is honest memory and how much is coming from your description.”

  “Of course,” the Shervah remarked in an annoyed tone.

  That was stupid of me. I should have let you do the describing, to avoid suggestion.”

  “I could never have done it to anything like that detail. If you think the distance is right, you’re probably as close as you’ll get. The part of the stream I used for a back sight was just about perfectly straight; I do remember that.”

  “All right,” agreed Carol. “That hasn’t happened very often as I came along. We’ll hope this is it. Stand by while I reset these keys—there. No pressure response, straight line along the stream section at about three quarters the speed I can run in this gravity. I’ll flash a narrow beam straight ahead every little while; you look back when I do—I’ll tell you—and let me know if you see it.”

  “Why not keep the beam steadily pointed ahead?” asked Charley. Molly and Jenny chuckled audibly; Joe was too polite.

  “Because I’d have trouble looking at the rocks, of course,” Carol answered patiently.

  “And I’m not pointing mine back very often, because if I do run into anything I want some warning,” added Molly. “I do hope you get here soon, Carol; I’m getting rather tired of this Juggernaut.”

  Even Charley needed an explanation of that symbol. Molly had to admit that the metaphor was slightly strained.

  By the fifth time Carol’s light had shone ahead without reaching her, Molly was becoming discouraged again. If both robots were following straight paths and the Shervah had picked the right direction, the distance between them should be quite small by now. The lights were powerful, and there was certainly no other illumination to compete with them—though when Molly turned her own lamp off, subjective glows and flashes swam around her field of perception. The rescuer’s light, however, would presumably not move with the watcher’s eyeball, and for the moment the Human felt some confidence in her ability to separate illusion from reality. She was beginning to wonder, however, how long she could expect this to last. The place was light-less except for her own lamp, soundless except for her friends’ voices, and practically weightless. She knew that a nervous system without input, like a nervous system whose input was at the edge of its sensory limitations, tended to amplify and organize its own noise. So far she had heard no music and seen no canals, much less angels or faces, but she found herself looking forward more and more eagerly to Charley’s voice checks and even calling one or another of her friends when she had nothing in particular to report.

  On Carol’s seventh try with her light, Molly saw something flashing from her backtrack direction and almost fainted with relief. She was doubtful enough about her own perceptions by then to ask her friend to flash the beam on and off several times, but the spark blinked in and out of existence in the same pattern as the sender’s call.

  “It’s you all right! Can you see my light? I’m pointing it back at you.”

  “Yes. I’m glad you picked that straight bit of stream. We’re a couple of hundred meters apart laterally; my direction was a trifle off to the right. I’m correcting and will be with you in a moment.”

  “Don’t stop talking. My ears as well as my eyes were beginning to deceive me. I was beginning to hear faint rumbling noises, and deep hoots and bellows.”

  “That may not be illusion,” Charley interjected. “There’s another storm—a really wild one—going on up here, and you aren’t so far from the surface, after all. Even Joe noticed it, though he doesn’t really hear; the boat’s been vibrating a bit.”

  “But would sound get through rock—I don’t mean that; it would travel better in rock, of course—but would it get through the rock-air interface well enough to be audible down here?” Molly was more than doubtful.

  “Carol, you can hear. Are you picking it up?” asked Charley.

  “I think so, now that you call my attention to it. It wouldn’t have to cross the interface, remember; there’s a closed tube connecting us with the surface for a good deal of the distance. Anyway, it’s not very important; when I get to Molly, we can check whether we’re hearing the same sort of sounds, if she’s still worried about her objectivity. I’ll be with you inside of a minute, Mol.”

  “And there are only two people in the universe I’d rather see right now. Thanks, Carol.”

  “I’m not hurt. I have three. Set your light for diffuse; I don’t need a beam now to spot you. I’m doing the same. Where will we have the party when we get back to our own? Pearl or Topaz? Your gravity and no air, or my gravity and your air?”

  “Right now I’ll settle for anyplace where water will stay liquid and in a tub.”

  “My place, then. I can melt water in the party wing, and you’ll need the air. Taking a shampoo in armor is a bit pointless. You’d have to refrigerate for me and the Others on Pearl, and I want to play some more with water anyway. I can think of some really good party tricks with ice.”

  Molly watched the approaching patch of radiance containing the other robot and its tiny rider, and for the first time in what seemed like days felt really free to get off her own machine and walk along beside it. Carol pulled a few meters ahead, stopped her robot, and also dismounted, and the tiny humanoid leaped to meet her huge friend.

  “Don’t squash me!” she exclaimed. “I’m glad to see you, too, but let’s not get overemotional.” Molly set her back on her feet, and the Shervah turned her attention to the first robot. After a moment, she gave Molly more instructions.

  “This may be a trifle awkward. You’re going to have to walk or ride with the middle of your back, where your heat pump exhausts, as close as you can get it to this place here on the shell. Your ice coat has frozen the access panel shut, and we’ll have to melt it away before I can get at the keys. I’m not sure the laser is controllable enough, and if it vaporizes any metal I might lose my eyesight even if the beam itself doesn’t hit me.”

  “No problem,” replied Molly. “I could walk on my hands in this gravity, and actually you could carry me in the best position, I suspect. How about trying it?”

  That’s a thought. It never occurred to me that a living person could be used as a blowtorch, but we admit human beings are a bit special, don’t we?”

  By the time the ice had disappeared from the panel, both women were feeling a trifle uneasy; Carol’s robot was some distance behind them. However, with the frozen water gone, she set her giant friend back on her own feet, opened the panel, and quickly manipulated the keys inside. The metal cylinder obediently stopped for the first time in many hours and, in response to further control, started back the way it had come at a somewhat higher speed. In two or three minutes it had reached the other machine, and Carol stopped it again.

  “Relief mission accomplished,” she reported. “We are together, and Molly and both robots seem to be all right. I can find our way back easily. I suggest we go quickly as far as the big cave where the life was found and learn what we can there; we’ll need specimens. All right, Jenny?”

  “Fine. I’m tempted to meet you there but have no intention of going outside in this storm. I might not be as lucky as Joe when I blow away. There are a fair number of hills around to make eddies, but I’m not sure I’d get close to one, and anyway there seem to be electrical discharges. My armor has metal in it.”

  “A good excuse for staying in the big cave for a while and collecting, if an excuse is needed,” agreed Carol. “All right, I think you can trust us to pick up all you need—for a preliminary study, of course.” The Shervah looked at her companion, who nodded
wordlessly, and the smaller woman set first Molly’s robot and then her own back into a traveling mode. She estimated a proper direction to bring them back to the stream, using the detailed mental picture she had formed of the parts of the cavern she had traversed so far. It was not straight back along the way either of them had come, but a little to the right of Molly’s back track; it should, Carol judged, intercept the stream two or three hundred meters above the point where they had left it. She did not want to cut any farther to the right, since there was obviously something—wall or ridge—preventing the stream itself from coming in this direction. If anything, as far as she could tell, they were nearly under the first large cavern, though some hundreds of meters to the left of the path they had first followed from it. Like Molly, she was rather uncertain of slope, however, and would have been reluctant to claim real confidence about their position.

  Her senses of direction and location, like those of human beings, were simply integrated memories of turns made and distances traveled; she knew that accumulating uncertainties in both would eventually put her badly off the truth. With only her own lights here in the caverns, there was little chance of long-range sighting, so direction errors in particular could accumulate quickly. Much too quickly for comfort.

  The discomfort was vastly amplified when, at about the time Carol expected to get to the stream, they reached what looked like a channel that had no liquid flowing in it. It was not completely dry; there were puddles, which she quickly identified as ammonia, along the depression, but in no sense was it a stream or brook.

  She reported at once to the others.

  “Check carefully against your memory,” advised Joe. “The first thought to strike me is that it is your brook, run dry for some reason.”

  “The storm?” suggested Molly.

  “Conceivably but not obviously. It is precipitating heavily here, and I would assume that the liquid must be ammonia. It would be easier to imagine ways in which your stream could have been overfilled from the surface.”

  “Streams and lakes are temporary things,” Molly pointed out. “They cut new channels and dam old ones with sediment. I’d say we simply have another set of observations to make, if this does turn out to be the same stream.”

  “It is,” Carol said firmly. “I remember a lot of what we see now. We are just about where I expected to be, a little more than two hundred meters upstream from where Molly and I both left it awhile ago. In another four hundred or slightly more we should reach the point where it first came in from the side. Just a moment while I reset the robots. Yours first, Molly; let me at the panel.”

  “Are the sounds you thought might be the storm any louder yet?” asked Charley.

  “No,” both women answered at once. “Dead silence outside the armor,” added the Human.

  “Was the change sudden?” asked Joe.

  “I don’t really remember. Probably not. Do you recall, Carol?”

  “If anything, I am less sure than you, but inclined to agree. If I’d noticed at all, I’d certainly remember; it just didn’t catch my attention. I’d hear better with no helmet, but I don’t think…”

  “You shouldn’t risk taking that off!” exclaimed Charley in a horrified tone. Molly, feeling her usual pity for the Kan-trick when he was taking things too literally, quickly changed the subject; fortunately, opportunity had arisen.

  “Carol! Isn’t that your rope?”

  “It is. I was beginning to wonder—just a little—whether my own memory had been overpowered by suggestion, but that settles any possible argument about where we are. I knew we should reach it before we got to the place where the stream came in but didn’t want to set you looking for it. We’ll be back in the big cave almost at once; we’re going faster than you were before, remember. Hold on a moment—it will be better if you walk, I think. I’m going to have to run from one of these machines to the other to keep resetting the guidance—no, I can use the wind again, can’t I? Just set them to move away from ram pressure…”

  “Not mine,” Molly pointed out. “We didn’t clear off all the ice.”

  “That’s right. We should have washed it at one of the puddles we passed. Here’s one now; let me stop the thing—there. I still have some empty specimen cans, and sloshing ammonia against it should do the trick. I haven’t worked much with ice, but if polarity means anything it ought to be soluble.”

  The cleaning process took only a minute or two, and the robots resumed their journey in somewhat wavering fashion; “downwind” was a less definite direction than the inertial one Carol had been using. The passage narrowed, as even Molly remembered, and presently the women emerged into the vast open space where Carol had first lost her friend’s trail. The fishline led off to the right.

  “We’d better stay with it. I wouldn’t want to guess how many openings there might be in the upper part of this hole, or where they might go, and I couldn’t see enough for real guidance on the way down.” Molly, who had never considered doing otherwise, fully agreed, and the robot controls were again reset. This time Carol did have to move back and forth for frequent readjustments; the wind was no longer a guide, and she had only a rough idea of the curvature of the rock wall.

  As Molly knew from the earlier conversations, there was about a kilometer to go before the rope trail would turn out across the cavern floor, and both students paid far more attention to the floor itself. There were the sparkling crystals that might be alive, the slippery patches and other areas that almost had to be, or that at least could represent chemistry on its way to becoming alive—a more believable state of affairs. Carol had paid little attention to this kilometer of distance, though she had traversed it three times already—once searching for the passage Molly had taken, and again and back to get the rope after finding the way. The first time, her attention had been on the wall, and the other two she had been in a hurry.

  Even so, she was aware of a difference as her light beam probed across the cavern floor. Then it had been irregular rock, sometimes bare, sometimes hidden by the mysterious growths and coverings they had both encountered. Now, however ...

  “Molly!” said the Shervah in a puzzled tone. “You never saw any liquid on the cave floor at all, did you—not even the little puddles I did?”

  “Nothing. There might have been some under the crystals, but all I found was that sticky stuff. We have some of it, and if I don’t encounter any more of it I’ll be just as happy.”

  “But look out there now! That’s not just a puddle!”

  The Human swept her own light in the indicated direction and saw that her friend was right. It wasn’t just a puddle. It was a lake, extending as far as the light could carry her eyesight. This was not too far—perhaps a couple of hundred meters, since she could not use really bright light with Carol beside her—but they had not yet come that far from “her” tunnel. She must have crossed this part of the floor only a few hours ago, and it was certainly no lake then.

  “The glittery stuff was all over this place earlier,” she pointed out. “We’d better see if it’s still there, underwater—I mean under the ammonia. I can’t really dive in this armor, but I should be able to see; how about you?”

  “We’ll both look. Come on.”

  The two explorers approached the edge of the lake cautiously, reporting the situation in detail to Charley and the others as they went.

  “Both of you watch your temperatures” was the warning. Not even Charley tried to discourage the research.

  Molly, fortunately, was ahead of her companion. “Watch out! Sticky!” she called suddenly, and with some difficulty retreated from the spot where her armored feet had tried to stay. She had not even reached the edge of the liquid, still half a dozen meters away. “This stuff was under the crystals before. I wonder what became of them?”

  “The part you met was under the crystals. We don’t know it was nowhere else,” the Shervah pointed out cautiously.

  “True. Let’s try a little farther along.” Molly approach
ed the verge more carefully this time, but was able to wade ankle deep before encountering the same difficulty. She bent over and groped with a gloved hand, again finding no trace of the glitter before she reached the adhesive. “You’d better stay out of this, Carol,” she advised. “I can pull free, but you’d find it harder. We should go back to the line I followed across here, as nearly as I can remember, and ... no, the crystals didn’t grow this close to the wall. We’d have to get well out in the lake to make sure they really aren’t there any more. Let’s go along the rope and check your line.”

  Carol agreed, and started the robots again. Twice they had to ride them, where the lake came to the very wall; one of these places, to Carol’s annoyance, was where she had slipped on something. There was no way to check if it were still there; the liquid was too deep. She mentioned this to her companion.

  The Human shrugged. “You got a sample before. If it had been ice, it would have dissolved in the ammonia anyway.”

  Then another problem claimed their attention. A little farther on, the rope turned and led toward the middle of the great cavern, as they had expected. Carol set the robot directions as precisely as she could from the lie of the rope. They mounted their machines, and Molly took the cord in one hand, allowing it to slip through her fingers as they floated slowly across the lake a few centimeters above the surface.

  “You should have taken this thing,” the Human remarked after a minute or two. “There’s a lot of your slimy stuff stuck to it, and I don’t have any collecting cans left.”

  “Let’s see,” said Carol from some two meters away. She turned her light on Molly as the latter held the line up for inspection. “Just a moment—I’ll steer closer and get some.”

  Molly agreed, and as the other robot drew alongside, she held the slippery length of material out so that her friend could scrape the lip of a can along it.

  “Of course, we could have waited and done this more easily where it lifts out of the lake,” the Shervah remarked, “but…”