Still River

by Hal Clement

  The Human described her technique briefly, not trying to comment on Charley’s words.

  “None of us can feel too guilty for not coming up with that one,” commented Jenny. “Who would have water in her armor?”

  “I’m not bragging,” assured Molly. “I should have gotten the notion long ago. Now, if you’ll forgive, I intend to stop observing for a while. I’m not sure I can really sleep on top of this thing, but I’m going to try.”

  “Are you sure that’s wise?” asked Charley.

  “No, I’m not at all sure; but it’s going to have to happen some time soon, and I feel safer right now than I have for some time past. I won’t turn the light out, and if anything really out of the way happens, the chances are I’ll notice—I hope. Right now, sleep is my prime order of business—unless I spot some life forms, of course, Carol and Jenny.”

  Joe, in the shop working on the new mapping robot, said nothing, and none of the others was in sight of him. If they had been, they would probably have been unable to guess his concern. Even Charley, who resembled him fairly closely in the eyes of the other three, was of a widely different body chemistry, physical engineering, and evolution, and would not have noticed or interpreted the suddenly increased effort the Nethneen put into his work as Molly finished talking.

  Joe might have been worried, but Carol, presumably in far more danger at the moment, was not. She rode the rim of her robot, holding on with one hand and grasping a collecting can in the other. Like Molly, she had clipped her light to her helmet for convenience; unlike the two males, she could turn her head, though her eye arrangement made this unnecessary. She was noticing only incidentally where she was going; like her Human friend, she could not feel the wind that was guiding the robot. She was, of course, hoping for more life forms; in spite of Joe’s emphatic denial of the possibility and her own knowledge that Enigma could not be a million years old and should not have evolved anything like the things she had collected, she knew what she had seen and had little doubt of its nature. A really close examination might prove her wrong, of course; she was burning to get the material back to the instruments in the bout and the tent, and the even more sophisticated equipment on Classroom, but she could postpone that while there was a chance of getting more data on Enigma. Her work, as initially planned, bridged that of Jenny and Molly; she was interested in the planet itself, physically, structurally, chemically, and biologically. She had not really expected the last aspect to appear, but since it seemed to have done so ...

  Carol’s emotions were less obvious than Charley’s, but she had them.

  She had found a stream, presumably the one that Molly had reported, and confirmed its composition with some of the safety equipment on her armor; it was not pure enough for her to drink, being loaded with dissolved salts, but it was ammonia. The robot was following fairly close to it, as Molly’s had done. The Human, when last heard from, had been following it back up, and it seemed likely that they would meet soon. Carol wondered in passing what Joe’s program would do with two robots in collision, but she didn’t waste any real time worrying about the matter. If anything of the sort seemed imminent, she could steer her own machine out of the way.

  The only thing that caused her anything like worry was the rope. She had made no effort to go back to her first landing point in the cave and lay a straight line to the new passage, so about a kilometer of it had been wasted by the supposed wind change. There was not very much left in the coil now, and she had not considered what to do if it ran out before she met her friend. She found herself keeping one eye more and more constantly on what was left, and as this dwindled to a few hundred meters she slipped one of her tiny, almost human hands into the control access opening in the body of the robot.

  “Jenny, Charley—I’m getting close to the end of the line and haven’t met Molly yet. Should I wait there with the robot, leave the rope and ride on, or leave rope and robot and scout around on foot, do you think?”

  Neither answer was surprising, but neither was very helpful.

  “Wait,” said Charley at once. “She should be back with you pretty soon.”

  “Scout on foot,” grated Jenny. “You can get more done while you’re waiting for her. She’ll see the robot if she gets to it.”

  “Not if she’s asleep,” countered the Shervah.

  “If she wakes up after passing it, she’ll see the rope.”

  “I wouldn’t count on it. It’s not very big, and I don’t know how its color contrasts with the rock to her eyes; do you?”

  “No, of course not. You have a point. It still seems a pity just to wait there, though.”

  “How long has she been asleep? Maybe we should wake her up when I get to the end.”

  “Not much over an hour. Nothing like her usual time. Make that a very last resort, I’d say.”

  “Right. Well, here comes the end. I’m stopping the machine for a moment at least, because the rope is fastened to it and if we decide I should take the robot farther I’ll have to untie it.”

  “How about pulling the rope straight?” asked Charley. From what you said, there’s a kilo or so been wasted by (he false trail.”

  “If I could do it myself, I might take the chance,” replied Carol. “With the robot doing the pulling, though, and its speed so firmly independent of outside factors, I’d never know until much too late if the rope caught on something and broke.”

  “Couldn’t you set the robot to pull just so hard?”

  “No. It has nothing to sense that. And don’t blame Joe; there was never any reason why it should.”

  “I wasn’t thinking of blaming anyone,” said Charley with surprising mildness. “Why don’t you scout on foot down the stream for a distance, after you park your machine? You’ll see Molly even if she does happen to be asleep.”

  Neither of the women could find fault with this suggestion. Carol left the rope attached as it had been and powered down the robot. Then, making sure that she still had several empty collecting cans clipped to her armor, she set off down the brook.

  It was not very deep, as she ascertained by wading in it. She was careful about this; her temperature tolerance was the narrowest of any of the group, and the present environment was about ten degrees below her minimum. Ammonia was her body fluid base, but was liquid at her temperature only because of the high pressure at which she normally lived. Her armor had good insulation, naturally, but she could feel the chill creeping into her feet before many minutes, and moved out of the stream.

  As Molly had said, there was nothing remotely suggestive of life to be seen, a fact that would not have surprised any of the group had it not been for Carol’s own find back in the big cave. Why it was there, and not here where liquid was available, was far from obvious. Several times the little Shervah knelt and examined the rock as closely as she possibly could, but it remained just rock. No glittering crystals, no slippery coating, no sticky material; nothing but rock. She announced as much.

  “Get a specimen or two, anyway,” advised Jenny. “Remember the planet has seasons. Maybe there are spores, or cell detritus, that we can find if we look hard enough.”

  “The hammer doesn’t get it loose; I’ll have to use the laser.”

  “Just don’t cook the whole specimen.”

  Carol followed the suggestion, but with no great enthusiasm. Rock analysis was all very well, and she enjoyed it in its place, but life on a world like this was something new. There ought to be more of it if there was any; life didn’t just occur in small, isolated bits. It came in whole ecologies, when it came.

  “Any sign of Molly?” It was Charley, of course.

  “Not yet.” Carol swept her beam downstream as she spoke. “No, not in sight.”

  “Judging by times and speeds, it seems to me you should have met by now. You didn’t get so absorbed in things that she might have gone by you without your noticing, did you?”

  Carol was too honest to make an absolute denial, but felt pretty sure that nothing of th
e sort had happened, and said so.

  “Did you get any distance from the stream?”

  “No. I’ve been in sight of it all along.”

  “Then that’s all right, I guess. Wait a minute, though! Since you left the robot, are you sure the stream has been going into the wind? Can you feel the wind yourself?”

  The Shervah spun and began leaping back toward the robot as quickly as she dared. Her normal gravity was less than Molly’s, but still far greater than that of Enigma, and she had the usual trouble coordinating her leaps so as to stay upright while off the ground. She answered as she ran.

  “No, I’m not, and no, I can’t. She could have gotten past me, at that.”

  Joe cut in. “I’m afraid it’s worse than that. Carol, you would remember; Molly would not have been aware. Has the stream been perfectly straight while you have been following it?”

  “No, not at all. I didn’t worry about it; in fact, I was hoping it would turn out that the stream had something to do with eroding this passage. After all, the robots followed it going into the wind all the time, so the passage must have been guiding the wind pretty much the same way—oh!”

  “Precisely. When Molly sealed one side of her robot to make it think the wind was coming from the other, in effect she would have caused it to fall back on its inertial system. That keeps the case of the machine oriented the same way, so it would have read pressure from the same inertial direction…”

  “Planet’s rotation, too!” interjected Charley.

  “Not significantly, in this time interval. The point is that she wouldn’t have followed back up the stream; she’d have gone straight in the direction that was upstream when she put on the ice coat. If she’s anywhere near the stream, it’s luck—of course, the passage can’t be too wide if the wind has been turning along with the river, so she shouldn’t be too far from it. Still, she could have reached the side and maybe worked into a side passage the way she did this one. Molly!”

  Several seconds passed. The Human, in spite of the limited area of the cylinder top, had fallen deeply asleep; she was still lashed in place, and the feeble gravity permitted head and extremities to be over the side with no particular discomfort. It took several repetitions of her name, in several voices, to bring her back to awareness. She had been wise enough to leave her light on, and avoided the panic that might have come from waking to a combination of total darkness and near-total weightlessness.

  “What’s the matter?” she asked as she pushed herself to a more nearly upright position. “Is Carol in trouble? I don’t see her.”

  “Of course you don’t; I’m nowhere near you, I’m afraid. The real question is whether you see the stream.”

  It took perhaps a second for the points that Joe had just covered with the others to marshall themselves in Molly’s mind, and suddenly she felt close to real panic.

  “Of course I don’t,” she replied in an unsteady voice.

  Chapter Twelve

  Of Course We’re Lost

  Carol cut in promptly and incisively, “Were you right at the stream when you started back, Molly, or some distance to one side?”

  “Ten or fifteen meters to one side—the right, in the direction I was going originally.”

  “All right. Joe?”

  “Yes, Carol.”

  “Everything has been logged since Molly went underground, hasn’t it? Instrument and conversation records?” “Certainly.”

  “Please give me, as quickly as you can, the time between Molly’s entering the crack—the one her robot almost didn’t fit and I had so much trouble finding—and the time she reported starting back. Molly, can you judge how much time you spent putting the ice coating on your robot?”

  “Fairly well. It was pretty quick—eight or ten minutes.”

  “How far did you travel between the time you started doing it and the time you finished and started back? Did your robot make any really wide or strange turns while you were doing it?”

  “No, to the second question. Not more than fifty or a hundred meters, to the first.”

  “Good. I know, to within a few meters, how far into this passage I have come. Joe’s time, when he gives it, should tell me how far upwind you traveled; and you are sure you never went very far from the stream going down it. I’ll calculate where you made the turn and get my machine there as quickly as I can, checking the brook to make sure the wind hasn’t changed too greatly. It shouldn’t be very long. Maybe there’ll be some trace of your work—some of the water you sprayed may be on the rock as recognizable ice. I’m not the chemist Jenny is, but anyone can recognize water by color. Just in case there isn’t any trace, you can spend the time I’m on the way describing the area as exactly as you can remember it. I know that won’t be very exactly, but any data can help. From there, we’ll have to—I’ll have to—take a chance that what seemed like the opposite direction along the stream to you will seem the same to me, closely enough so that when I set my machine along a line it will be the right one.”

  “You’ll be beyond the rope, Carol,” Charley pointed out. “You already are.”

  “Can’t help it. Can’t wait. Molly’s still traveling. I can remember what I see well enough to get back to it. I thought of going after her on foot for a moment—I’d be more able to spot any trail she might have left, or details she might remember—but it seems safer to keep the robot with me, and it should be able to go wherever hers has.”

  “Nothing very remarkable to report so far,” Molly interjected.

  “Since you woke up, you mean. All right, I’m ready to start as soon as I get Joe’s log figures.”

  The Nethneen responded at once, and after a few moments of mental arithmetic Carol was traveling. “I should get to the place where you did your ice job in less than an hour at this rate, and if I manage to hit your line closely enough I should catch you in maybe an hour or an hour and a quarter more, Molly.”

  The Human acknowledged; she had not finished doing the arithmetic herself and didn’t think she was getting quite the same answer; but of course Joe would have used either School or his own time and distance units, and her translator would have rounded both of these—no, that couldn’t be it; Joe would have expressed himself quite precisely, and the computer on her wrist would have gone equally far in significant figures. Probably Carol was considering factors of her own, like time to reset her own robot’s programming. Molly wasn’t really awake yet, she began to realize, and this wasn’t good. She must see and remember as much as possible of the route she was following, so that she could give the Shervah some sort of reasonable description if one were needed.

  She swung her light around—that might serve another purpose; if they were still in the same cavern, Carol might see it. Certainly the place she was in was large; no wall was in sight in any direction. There must be a roof, but it was too far above to let her distinguish any real details. The floor, of course, was right below. Molly shone her beam alternately forward and backward, trying to decide whether or not the floor was level, but was unable to make up her mind. Presumably the cylinder’s own attitude was erect, but it was small, and her own semicircular canals were of little help in this gravity. She found herself sure at one moment that she was going down a fairly steep slope and seconds later just as sure that she was climbing.

  The floor was rock, not quite like any she had seen before on Enigma, but not very different; whether the change meant anything she could not be sure. It still seemed rather loose, friable stuff. Nothing resembling igneous rocks with which she was familiar had shown up so far on Enigma. She dismounted and took a closer look, reporting the nature of the material as precisely as she could to the others and cutting out a specimen at Carol’s request.

  “I know I can get one myself if I find you, but your dig will make a mark that will tell me I’m on the right track. We should have thought of this earlier. Make a hole in the rock every few minutes—use your laser if you have to.”

  “I haven’t seen much that
really needed it yet,” replied Molly, “but I’ll do better than that. I’ll mark an arrow—does that symbol translate?—all right—to indicate which way the robot is going. I might even run off to the sides every now and then and make arrows pointing toward the trail, just to improve your chances of hitting it. There are occasional patches of dust now; I won’t always have to use the hammer, even.”

  “Dust or salt?” asked Jenny.

  “I couldn’t say. Very, very fine powder; I don’t have equipment to check the composition—I certainly don’t intend to check whether it’s water-soluble, and the ammonia brook is still out of sight. To forestall your next request, I have no more unused collecting cans, Jenny; you’ll have to hope Carol hasn’t filled all hers before she gets here.”

  Silence fell for some time, interrupted only by Charley’s occasional check questions and, more rarely, by Molly’s description of some change in her surroundings. She was almost, but not quite, sure now that her path was again descending quite steeply.

  “Any wind that you can feel?” asked Joe.

  " ’Fraid not. That doesn’t mean there is none—wait a minute; here’s another patch that might be sand or dust. Let me try something—hey, Carol, there’s a crust on this; the surface is hard. It looks like dried, cracked mud. There’s fine stuff underneath, though. Just a minute. Joe, there’s a very slight breeze, enough to carry some of the finest dust as I drop it, going roughly from right to left across my present path. Very weak indeed—in the centimeters-per-second class, I’d say, though at the rate things fall here my time sense is getting ruined, too.”

  “Note that, Carol.”

  “Don’t worry, I wasn’t going to use wind to follow her, Joe. I think I’m about at the place where she used the water now. You said you were a few meters to the right of the stream, Molly?”

  “That’s right.”

  “Well, I don’t see any ice stains on the rock, but I suppose you’d have been careful not to waste any.” “I certainly was.”