Still River

by Hal Clement

  “Well—nothing special. It was the first thing I could think of that wouldn’t be as obvious as high winds or holes.”

  “Have you ever had experience with such a thing?” asked Joe.

  “Not personally. I’ve read about it.”

  “All right,” said Molly, “I’ll step carefully, and in this gravity I don’t think I need really worry about that, either. No, don’t say it, I know I’d sink just as deeply into any liquid here as on my home world, but I can use inertial effects more constructively here, I’d think. We’ll hope I don’t have to find out, though. I won’t be long; I’ll get water and mud for analysis and be right back.”

  Charley made no answer, but settled down at his dimly lit screen and keyed it to cover the area just outside the nearest lock. Molly quickly rechecked her armor and went out.

  There was more light than before; the clouds seemed to be thinner for a moment. She had already mastered the coordination needed for walking in seven-percent gravity, of course, and required no conscious thought for that problem, so she could focus full attention on the landscape before her.

  The nearest lake was about two hundred meters away. There was just enough wind to make its liquid state obvious by ruffling the surface into small waves, which moved with eye-catching slowness in Enigma’s gravity. Considering the temperature and pressure, its main constituent was presumably ammonia, but there was no reason to suppose it was very pure.

  The ground at her feet was mostly the light-colored material that Jenny claimed to be ammonium salts, but now it could be seen that smaller, darker pebbles were scattered through it. Molly collected several of these, finding that they were filled with tiny, sparkling metallic-looking particles when examined closely. She reported this to Jenny, and walked slowly on toward the lake.

  “Everything all right?” asked Charley.

  “Eh? Oh, yes. Sorry—I promised to keep reporting, didn’t I? So far nothing special. The surface holds me up well enough and seems perfectly dry so far. As you can see, I’m heading toward the lake now.”

  “Not too fast. You don’t have Jenny’s traction, and you want to be able to stop.”

  “True. I’ll watch it, though getting wet with ammonia shouldn’t hurt me in this suit. My batteries are up, and I could boil a lot of it away from around me before getting frostbite.”

  “But I couldn’t see you under the surface.”

  “I’m not sure I’d sink; I’ve never stopped to figure out my density in armor, and would have to look up that of the ammonia. In any case, if I go under for any reason, I’ll keep talking to you. In fact, now that I think of it, getting mud from the lake bed might be a good idea; if there’s any sort of microlife on this world, the bottom of a shallow body of liquid with some decent light shining on it would seem to be the best place to look for it. Now stop worrying, Charley. I can’t guarantee there’s nothing dangerous, but I’m not going to take any unreasonable chances. I want to see my husband and little boy again, the sooner the better as long as this job is properly done. Do calm down.”

  “All right. I didn’t mean to be giving orders. It’s just that I was so surprised when Joe blew…”

  “So was I, and so was he. The universe is full of surprises, thank goodness. Some of my ancestors believed in an evil god they called Satan, but his real name was Boredom. Hold on a minute, here’s a patch of something that looks different. Sort of pink, no, more orange, with little veins of yellow. Its texture is slimy, of all things. This is encouraging; maybe we have Jenny’s life already. I’ll can some of it ... there. It sticks to my gloves. Probably I can rinse them off in the lake. Wait a minute.” She took a long, gliding step that brought her ankle deep in the liquid. “It doesn’t shelve off too quickly. I’ll get some of the bottom stuff in another can while I’m here. There; at least the gloves look clean. I’ll rinse them off again with a couple of different solvents when I get back to the boat, and Jenny can play with those washings, too. Now I’ll go out a little farther and get some deeper tuff.”

  “Do you have to?”

  “Why are we here? If it will make you feel better, I’ll come back to the boat and let you do it, but that seems a waste of time with me here already.”

  “Well—I’ll go out next time.”

  “Fine. I was going to suggest that anyway.”

  Molly waded away from shore and boat, occasionally pushing her faceplate below the surface to get a clearer view of the bottom. It looked like plain mud or sand; there was nothing that suggested living beings, plant or animal, protist or argilloid, though she could hardly expect to see either of the last two except in colony form. She Finally reached waist depth.

  “I’m going to get some stuff from the bottom. One liquid sample, one mud or whatever. I’ll be down less than fifteen seconds, if I can get down at all.”

  “All right.” Charley tensed himself at his station. He was extremely uneasy in one way at losing sight of his partner, though he still had faith in the Faculty that had set their problem.

  He needn’t have worried. Molly had been able to immerse her face when she wanted to see the bottom, but getting entirely below the surface was another matter. She couldn’t sink, and her center of buoyancy was if anything below her center of mass. She just couldn’t reach the bottom. Getting her feet back down after lifting them off took some doing. Even Charley was amused. Swimming was not an art with his species; as he had said, they floated even in liquid ammonia, and with no need to breathe they had never regarded staying up as a problem. Their shape and mass distribution made it easy to stay right side—head pole—up if they were floating; Molly’s present need to go head down, coupled with her already weird shape, made the situation really funny.

  “Blast!” exclaimed the Human when she was finally standing again. “I know ammonia’s a lot less dense than water, but so am I with this suit. The recycling gear takes up too much room. I ought to have designed it with the batteries in the feet. I should have learned more than organometallics when I was taking that course with Jenny on Ivory. The gravity made me spend a lot of time swimming there, and of course I didn’t use real armor—just good insulation, which bulked enough to let me float in the ammonia but didn’t keep me from diving.”

  Charley knew what she meant; he, too, had taken courses on the high-gravity fourth planet of Smoke, the fainter star of the binary system whose planets had been taken over almost completely by the University.

  “I’ll have to make do with shallow-water samples this time and rig up some sort of long-handled scoop for the future. I’m coming back. Don’t gloat.”

  “I’ve been listening, Molly” came the grating Rimmore tones. “If you need to make more equipment, how about coming back to the tent with the specimens you already have? I can’t wait to work on that slime you were talking about.”

  “Well—all right, Jenny.” Molly had intended to use the shop on the boat but could sympathize with her friend’s curiosity. “I wouldn’t mind knowing what the stuff is myself. You don’t mind waiting for stuff from other lakes?” She splashed out on the shore, noting that the material underfoot was more mud than sand; it clung to her feet and ankles. She made no great effort to get rid of it; specimens were specimens, even if they collected themselves.

  Actually, most of it had dried and fallen away by the time she reached the little spacecraft; her trail was marked not only by the indentations of her footprints but by the fragments of hardened mud. She did not stop to think of any implications of this rapid evaporation; after all, her armor was heated to keep her alive.

  “You might as well fly, Charley,” she remarked as she closed the outer lock behind her. “I’ll have to get this stuff properly recorded.” Her companion made no objection, and by the time they were back at the tent—a far shorter trip than the outbound one, since neither of them was bothering to observe and the Kantrick used far higher speed than before—she had labeled her specimen containers more completely, described each with a brief note covering its reason fo
r collection and location, canned several of the flakes of sediment still adhering to her armor, and topped off the batteries of the latter.

  Jenny received the material with eager nippers, listened to Molly’s backup information, and settled down happily to work. Charley and his Human friend went to see the beginnings of Joe’s air-current map; the Kantrick remained to watch it grow, though there was still little sense to be made of it. Molly retired to the shop to make a shovel. This was completed in a few minutes, the shop resources being what they were, and she then suddenly realized that she could use some sleep. No one had set up a watch system as yet; the students were doing what came to hand. There was no objection to further delay in the inspection of the daylit region.

  Sleep was rather uneasy this time; Enigma’s gravity was a great deal less than the normal Classroom acceleration, low as that was by Human standards, and Molly woke up several times from a falling dream.

  Her conscience eventually decided that she had rested enough, and she took a quick meal before going back to the tent. Her translator had of course blocked all nonemergency communication while she slept, and the first words to come through when contact was resumed rather surprised her.

  “Joe, I would never have thought it of you!” The voice was Carol’s; the machine was using the tone of honest surprise, but Molly rather suspected sarcasm. She was not yet in sight of the others, being twenty or thirty meters from the lock that led to the tent, and found herself at a loss for the motive behind the Shervah’s words. Had Joe actually interrupted someone at work, or what?

  She hurried, making full use of the handholds, but her first view of the tent occupants told her nothing. All four were gathered around Joe’s map, but there had been no more words and no one appeared to be doing anything but look. Molly joined them as quickly as she could, and looked the map over silently from all sides, hoping to learn what had provoked Carol’s remark; but she saw nothing surprising.

  The map itself was a holographic projection of the planet, about two meters in diameter. The sunlit side was indicated by what to the Human was slightly brighter illumination, and a coarse coordinate grid indicated the rotation axis.

  Faint reddish and orange lines, all so far extremely short, marked the paths that had been followed by the robots, and the locations of each of these were indicated by slightly brighter sparks of light at the appropriate end of each line. In each case, the starting point could easily be identified as the spot from which the trails of each robot and its five slaves radiated. Presumably, as the lines lengthened, it would become possible to make some sense out of their pattern, but Molly could see nothing organized so far.

  There was, of course, no meaningful connection between the starting points and the coordinate system. One of the twenty was at the arbitrarily chosen zero longitude, and neither rotation pole was anywhere near one of them, since chance had not brought them to the ground at an appropriate latitude—Molly realized with some embarrassment that she would have had some trouble calculating in her head just what an appropriate latitude would be. How many degrees apart on the circumscribed sphere were the vertices of a dodecahedron? She put that one firmly out of her mind, and returned to the possibly more immediate question.

  What had Joe done or said to surprise Carol? Of course, he would never have made a remark about the pattern’s already supporting his hypothesis—not Joe.

  “Does this make sense to anyone yet?” Molly asked.

  “Notice the summer end of the axis,” replied the Nethneen. What Molly actually noticed was that he had not really answered her question; but she backed a little farther from the globe image to get a better view of the area in question, and examined it more closely.

  The true arctic circle had not been located yet, since no one had bothered to check the orientation of the rotation axis with the planet’s current radius vector; but presumably it was farther from the pole than the circle now in total daylight. Within that circle were only two of the robot tracks, and Molly examined these very carefully. It was the area they knew to be more heavily clouded and that she and Charley had been examining more closely, but the map showed nothing of the clouds.

  “I don’t see anything very different about them, she admitted at last. She was embarrassed again; if Joe had spotted a difference, surely there must be one. What could be expected to show this quickly? The region was presumably getting more heat, of course—potentially higher winds, but if anything the patterns of radiating lines were smaller suggesting slower air currents. It couldn’t be that.

  “See the wind strength?” Carol still sounded sarcastic. Would Joe be drawing conclusions already about general circulation? It was a temptation common to Human minds—she wasn’t sure about many of the other species—to notice things that supported one’s one preconceived ideas. Surely Joe was above that, though; or was he: Did the robots measure vertical components? She tried to remember.

  Then she suddenly saw the larger pattern. “Oh! Of course! What can have happened? When did it happen?”

  “I only noticed it a few minutes ago,” replied Joe. “I’ve had to take some readings from other sensors on the slaves to make sure, but the air is generally rising over that area, and…”

  “But I meant the other thing—the missing robot!” exclaimed Molly. “Isn’t that what you were talking about?”

  “Oh, no. That couldn’t happen. Of course they’re all…” Joe fell silent as he realized that Molly was quite right.

  Chapter Eight

  Of Course, It’ll Be Soft

  The boat hovered a hundred meters above Enigma’s surface, with all five occupants staring intently into their screens. It was daylight, though dim, even by Molly’s standards, since they were close to the summer pole, and all were using the light that most nearly suited their own eyes. Meter by square meter they were searching the landscape for the missing robot.

  The surface was different here. Rock and sand were interspersed, as they had been elsewhere, but crater-topped cones were scattered freely; they had seen dozens in the last two or three hundred kilometers as they approached the final recorded position of the lost machine, and five were visible from where they now hung. Nobody wanted to believe in active vulcanism on a planet this small and young, but nobody could think of another name, or another explanation, for the cones.

  And nobody could see the glint of metal against the sand or the rock. Joe, dividing his attention between his visual screen and receivers set for the robot’s telemetry broadcast, had had nothing to report, either. Jenny had put her chemical work aside and was searching as earnestly as Molly, but neither had seen anything worthy of comment. Carol was very interested in the local topography and might conceivably have been paying more attention to the hills than to possible metal cylinders, but she was tactful enough not to make irrelevant comments. Charley was the least restrained, as usual.

  “Joe, have you picked up anything from the slaves of the missing unit?” he asked after many minutes of futile circling.

  “I haven’t tried. They were on a different frequency and were transmitting to the master to be relayed from it. Naturally, we lost touch with them when it went out.”

  “But if they are anywhere around broadcasting, couldn’t we pick them up directly?”

  “We should be able to. I’ll try it.” The Nethneen operated his keys briefly, and his voice showed emotion that might have been enthusiasm or might have been annoyance—Molly could have sympathized with the latter. Why did Charley have to be right? “Yes. They’re radiating—all five of them.”

  “Where are they?” came several voices at once.

  “That will take some work. The original setup was designed to locate them relative to the master. We may have to get directions and go back to crude triangulation ...” Joe fell silent and his tendrils worked keys again.

  “What were their heights?” asked Molly from the boat controls. “I’ll get us level, or nearly level, with each of them in turn, and we can home in on it if you can
get direction.” She sent the craft floating upward as she waited for Joe’s reply, knowing that the lowest of the slaves was at five or six kilometers. She also set up an outside pressure reading for her own screen, remembering that the things had been set for pressure rather than absolute altitudes.

  Twenty minutes located all five of the devices, since Joe elected not to bother to bring them aboard. Horizontally, they were all within about fifteen kilometers of the spot where the master robot had last indicated its position, and very much closer than that to each other. There was still no sign of it in that neighborhood, however, and no obvious place where it could have been hidden. Enigma showed no evidence of tectonic activity hereabout unless the “volcanoes” counted; there were no canyons, caves, or cliffs with landslide evidence—or without, for that matter. There were no lakes within ten kilometers, and the few that lay within twice that distance seemed at casual inspection to be shallow, though this might have to be checked. There were no biological hiding places like forests.

  “Will radar get through ammonia far enough to check those lakes, or will we have to do each one personally?” queried Joe.

  “Depends on their depth,” replied Carol. “It won’t go very deep. The ammonia must have electrolytes in it—right, Jenny?—and will be a fairly good conductor. We’ll try. Who’s densest?”

  “I’m made of water,” replied Molly, “and we can add enough weight to my armor to let me submerge. I can almost certainly see farther than any of you through the stuff, with my short-wave eyes. That would let me do a search most quickly.”

  “That is all true,” replied Joe, “but any of the rest of us, except perhaps Carol, would be safer. Jenny’s done it so far, with no trouble. The ammonia is, for us, at a relatively comfortable temperature. While your armor should keep you alive, if anything should go wrong with it you would be in far more danger than one of us. I suggest that Jenny and I search the lakes, weighting our armor as she did before; I because it is my problem, and Jenny because she would be able to observe and sample the lake bottoms, in connection with her own work, at the same time.”