Still River

Chapter Twenty-Three Of Course I Can Get A Spectrum

Molly was more certain than ever that Joe could feel emotion as his latest report came through her translator.

“How do you know they’re missing?” She put the question as calmly as she could, remembering how the Nethneen had been so careful of her own feelings earlier. “I thought you couldn’t identify their individual signals.” “I can’t. That’s why I was so slow realizing what was happening. Several of the branches—the passages—in the present section of the model have simply stopped growing. Since others were extending normally and the pattern is fairly complex already, the frozen ones weren’t obvious without careful examination. Carol, with her memory, might have spotted the situation more quickly; I could not.” “Couldn’t the passages simply have reached dead ends?” “That would have been indicated; a good many have been. Some things I did foresee clearly enough to program. I cannot see any interpretation for this other than a stoppage of incoming signals, though the fact that the height of the surface over much of the mapped area has changed slightly—a centimeter or two—may also be relevant. I am of course heading for the nearest of the frozen branches as quickly as possible, to see for myself what’s happened.”

Molly just managed to restrain a comment about possible danger. Joe would be careful, of course, but he could no more ignore the situation than could Carol or, basically, than Molly herself. It was Carol who actually spoke, and it was some time before Molly realized that the Shervah was also giving prime thought to analyzing the danger—the danger to the mappers, of course.

“Joe, don’t go too fast. Please examine and describe as carefully as you can the nature of the rock, or whatever may form the walls of the passages you traverse. If you have time to stop and take samples, or even do a quick spectral analysis, do it.”

“You have an idea of what may have happened?”

“Not a full scenario. A possible backdrop. Get the data to me, please.”

“I will. I am just approaching the surface. I told you earlier that this area was much smoother, according to the radar model, between the actual tunnel openings than it is farther from the poles. I have not seen such material before on my own world. As I approach, the smoothness starts to show a pattern of cracks outlining polygons of usually five or six sides, anywhere from four or five centimeters across to eight or ten times that size, the edges rather curled up—pardon the word—away from the surface and toward Enigma’s interior.” One of Carol’s eyes rolled toward her companion; Molly caught the glance and nodded.

The Shervah interjected a question. “Is that concavity true of all the polygons, or are some of them flatter, rougher, and set farther from the surface—as though a curved plate such as you are describing had been removed?” Joe gave no answer for several seconds; Carol and Molly waited patiently, knowing that he must be making a careful search for the sort of feature she had suggested. Charley’s voice started to sound, and ceased again before he had completed a word.

“Your idea has substance,” the Nethneen responded at last. “A great many of the markings—fully an eighth, in the area I can see clearly—are as you describe. The percentage is greatest close to the tunnel mouth.”

Again Molly nodded. It was she who spoke this time. “Joe, can you take the time to stop and pry or kick loose a few of those polygons? We’d like to know where they go, and how fast.”

“Certainly. One to two minutes, please, while I check my armor.” Not even Charley made a sound this time.

“They are rather fragile.” The voice finally resumed. “Most of them break, no matter how carefully I try to detach them. They are attached to the substrate with some tenacity. Not enough to make them difficult to remove, but enough to make them hard to remove intact.”

“It doesn’t matter whether they break or not. The pieces will be just as useful. They aren’t falling, of course; but you didn’t report any floating around as you approached, so they must be leaving somehow. Which way are they going?”

“Toward the nearest tunnel mouth. They are being carried by the wind.”

“Right. Does your translator handle the word mud?”

“An approximation symbol comes through; I don’t know how it would return to you. Is slurry adequate?”

“Fairly. Mud would have less liquid and more viscosity, generally speaking, but I couldn’t give you a numerical boundary composition distinguishing the two. You’ve described a surface of mud that has dried, shrinking as it lost liquid, and some of the plates formed by the resultant cracking have been blown away. The rivers must get to the central hollow at some season or other of Enigma’s year…”

“First from one pole and then the other!” Charley interrupted gleefully. “I see. The mud season has passed, the mud left in the center has dried, and rivers are drying too under the hot wind. It makes sense.”

“Which does not necessarily make it true.” Molly felt she had to say it; it was more properly Joe’s line, but it was likely that he wouldn’t want to interrupt. This was neither emergency nor incipient quarrel. “I agree, Charley. A stratigraphic study of the mud should tell us a lot about Enigma—it might even contain enough organic remains to let us reconstruct the life history. For that matter, it might even tell us why the mud, when it does come, spreads out in a fairly smooth layer over this part of the inner surface, with what gravity there is tending to pull it toward the center.”

“Wind, of course,” remarked Charley. Molly glanced toward her small companion. The latter’s mouth was almost invisible even when she was not wearing armor, since her face did not include a chin, but silent lip motion could be discerned. Molly made a silencing gesture, and the Shervah nodded. Her friend went on, “I admit hydrogen bonds are stronger than gravity, but I have a very foggy mental picture there. The main point right now is that the mud flakes, when loosened, blow into the tunnels. There must be a lot of detritus there. Much of it may get reduced to the sort of powder we met blowing from the surface, much of it may get cycled through life forms, but some of it right now may be causing the trouble with Joe’s mappers.” “How?”

“I don’t pretend to know. With no gravity at all, practically speaking, it could hardly be any sort of tunnel collapse. You said there’d been some surface change. Just keep any eye on the passage walls as you go, Joe.”

“Most assuredly.” Joe was always happier with a working hypothesis around, even though he always expected it to need modification. “I’m entering the passage now.”

“Are the walls still mud? Do they show any stratification?”

“To the first, apparently yes. To the second, I can’t tell, Carol. I would expect to have to section the deposit to see.”

“I was wondering whether there might have been a river through that passage to do the sectioning. How such a system would behave in weightlessness I can’t guess. We’ll have to come back two or three decades from now and try to catch this place with water reaching the inside, at one or another of the poles.”

“I am sure that will be done. I wouldn’t mind being one of those to do it, but if I manage my Respected Opinion rating I’ll presumably be working somewhere else long before then.”

“You don’t have it yet, Joe?” Charley was clearly startled.

“Of course not. I was under the impression that none of us was even up to Considered Word. I did not, of course, inquire how far any of the rest of you had to go, but one more really successful project after this one—if this turns out as well as I’m beginning to hope—should satisfy my requirements. One must admit, of course, that a certain subjectivity occasionally shows in Faculty ratings, as even most Faculty members will concede, but one does not worry about facts beyond actual control.”

Charley made no comment. He might have wanted to, but Carol rather pointedly repeated her question about the composition of the walls surrounding the Nethneen. Joe returned to business. The passage still appeared to be winding its way through dried mud, though whether this represented a thin covering over rock or a bore through kilometers of sediment could not be told by simple inspection.

“I’d vote for lots of sediment,” Carol said thoughtfully “It’s an interesting bet whether this temporary hollow is going to fill first from rock creep or sediment transfer. There’s no way it can last indefinitely. Yes, I said creep, Molly.”

The mud itself was very salty and rather brittle; Joe stopped and emerged from his mapper long enough to ascertain these facts. He did not try to dig into it for any distance. The flare from his laser indicated, even to his eyes, that either the salt or the mud itself was very rich in sodium, but detailed information would have to wait until the fragments he collected reached the laboratory.

He had passed wind-borne flakes of what seemed to be surface mud other than those he had detached himself, and judged that the wind loosened these occasionally and bore them on up toward the outer surface. He wondered what would happen when gravity became strong enough to oppose the wind effectively for one of these, and began to get an inkling of what might be going on in the tunnels ahead. He thought of slowing his flight, then remembered the women and continued as he was.

The inactive branches were mostly well away from the inner surface, but one seemed to start less than twenty kilometers from the original passage mouth, measured along the route he had to follow. The path showed clearly enough in the computer model, but as he approached the indicated tunnel the Nethneen slowed somewhat and watched carefully ahead, using his mapper’s lights and radar as effectively as he could. He had now set his computer to warn of any change in the tunnel shape or topology by the same contrasting color technique. If he had done this somewhat earlier, he would have been spared inconvenience and anxiety.

Nothing gave any warning, however, for nearly another ten kilometers. Then he reached a section where, according to the model, there was barely enough room for his own vehicle to pass. Had there been too little, the small machines would have interpreted it as a dead end and stopped mapping, but they had gone on. Joe did the same.

He had become a little remiss by now in checking the details of the passage walls; Carol had stopped reminding him. Molly insisted afterward that it would have made no difference. Even she, used to winds and their peculiarities, would not have expected to foresee just what happened; Joe, from a practically airless world, would hardly have had a chance.

Joe himself insisted that Charley’s experience at the crater where Molly and Carol had entered the caverns should have been warning enough if he had kept properly alert.

He was never sure whether his vehicle actually brushed the loose mud of the passage wall as a result of careless piloting, or simply left such a narrow space for air to get by that the wind did the damage. Whichever happened, some of the sediment broke free, leaving a hole that gave the wind a real grip on the rest; and within seconds the passage ahead of him was full of blowing material ranging from fine dust grains to fist-sized clods. Joe’s unfortunate reaction was to cut power for a moment to let the stuff get ahead of him; it was blinding in both visual and radar wavelengths. Unfortunately, the local gravity was still less than three millimeters per second squared, and the wind was quite able to move the robot he was riding. The shuttle-shaped polymer hull, a meter and a half in diameter and five in length, twisted erratically, and first one pointed end and then the other struck the passage wall, gouging out more clay and salt before jamming in place. Large fragments flying from the original disturbance site struck it. Some of these pulverized and were blown past, other proved more resistant and in many cases got themselves jammed between hull and passage wall. Before the Nethneen had a clear idea of an appropriate maneuver, the wind had stopped, blocked by a new plug composed of freshly moved sediment and his own mapping machine.

It did not seem a dangerous situation, particularly. He had lost his personal sense of direction for a moment, but there was enough gravity to tell him which way was down, after a little careful checking with loose items he had on board. He could not see outside, of course, being completely buried, but he was sure the burial could not be very deep. If the robot’s power would not push it through the deposit without damaging the hull, he could go outside himself and do some digging—with due precaution against being blown away again when he did get through and the air was once more free to move. Once was quite enough, even weightless.

At this point Molly, of all people, asked whether there were any evidence of what had happened to the mapping robots. Since it seemed clear that the tiny objects could never have triggered an event like this—their automatic controls would have prevented them from touching the walls, and their size would have kept them from changing wind speed significantly in any passage large enough for his own machine—he replied truthfully, he felt, that no evidence was yet forthcoming. He preferred to say nothing about his present minor predicament until he was out of it, of course.

He then applied driving power, gradually increasing the thrust until he began to worry about the strength of the robot’s shell. There was no motion that he could feel in his craft or see in the surrounding sediment.

He thought briefly again of digging, but then remembered that the hatch opened outward. He did not even try to move it. He was strong—nearly as strong as Molly, in spite of the feeble gravity of his home world—but knew his limitations too well for that.

After a few seconds more of thought, he returned to the control keys, concentrating this time on attitude rather than motion. It proved possible, finally, to rotate the robot on its long axis—Joe remembered, with a slight shudder, that he had briefly considered giving the machine an elliptical rather than a circular lateral cross section merely for appearance’s sake—and within a few minutes his equipment was boring its way gently out of its tomb.

Once free, he reported in full, including his reasons for doubting that this was what could have happened to the small mappers. “I’m a little bit unsure about whether to go back through this mess and continue checking this branch, or check out one of the others,” he concluded. “I am sorry to say I dug my way out on the downward side of the block without thinking.”

“You were thinking better then than you are now!” snapped Carol. “Your next maneuver is to get back out of the tunnels into the open and recall your machines. Count them out where you’re safe, and incidentally where their radars will pick up Molly and me when we get through. Leave them out there, or most of them. Spread them to cover as much of that inner surface as possible. When that’s done, you might take a few and go check one of your dead tunnels, if you like—well, of course you have to—but don’t get all your mappers committed to an area that seems to be eating them, just yet. Get them out of there. I’m very glad we know about what this mud or clay can do in a high wind and no weight, and we will be extremely careful when we reach tunnels that seem to be made of it, but untie the knots in them before you stretch your arms any farther.”

Molly sympathized with her companion, though she could never have brought herself to be that emphatic with Joe. She added a quiet “It would be nice to know just how many of those little mappers really are left” to Carol’s diatribe, and waited for his answer, which was quite predictable.

“You are quite right; I should have withdrawn the other robots before starting this investigation. I’ll go back and take care of that immediately.”

“And please tell us when you’re out in the open again,” added the Human.

“There are no more such constrictions on the way out, but I will certainly report. It will take a little while to make even an approximate count of the robots; I should have included provision for individual monitoring.”

“You can’t either foresee or take care of everything, Joe. A fiction writer, years ago on my home world, complained that the trouble with writing adventure stories was that adventures happened only to the incompetent and he or she—I don’t remember which it was—felt unhappy writing about incompetent characters. The readers, he felt, were bound to recognize each mistake as it happened and sneer at them. It just doesn’t happen that way; if it did, none of us would make mistakes—and life could actually become boring. Horrid thought. Go on back to the hollow, Joe, check your machines, and keep in touch with us. Even there, things might happen that none of us has foreseen. I think we’re in more danger at the moment than you are, but I’m far from certain of it.”

Ten hours later, Charley reported a gravity of thirty in the usual units; presumably he was over halfway to the center. Jenny had found fundamental genetic biochemistry suggesting eight different planetary origins in the specimens she herself had found and brought back to the tent; there seemed no reasonable doubt that Enigma had been repeatedly seeded, and ordinary evolution been busily at work developing a fascinating ecology of the results. She was still working. The original atmosphere problem had been almost forgotten; objectively speaking, the guess that had been made toward a solution was still in the hypothesis class, but the flood of new questions had left the group willing to accept it so their attention could be freed for other things.

Joe had found that many of his robots were indeed missing, but fewer than he had guessed; there were still three hundred ten in service. This, of course, did not lesson the problem of what had happened to the other two hundred or so; he would long since have returned to the caves in search of them if another difficulty had not developed.

Molly and Carol were still following a river of unknown size. Gravity suggested that they might be nearly halfway to the inner surface by now, according to Carol’s observations; but Molly was unable to check them.

Her vision had been getting progressively worse. The urge to blink and squint had increased, the blurring had grown more and more extreme, and occasionally she could feel liquid running down her cheek—slowly, and only when an accumulation that made seeing hopeless had finally been dislodged from her cornea by frantic blinking and head shaking. She had nothing to serve as a mirror and could not tell whether the liquid was ordinary tears or something else. Carol, who could see the drops, was not familiar enough with Human physiology to report anything useful. Her color sense was different enough from Molly’s to make even basic description quite useless; there was no way for the translator to handle color symbols, and it simply reported the fact.

Both carried elementary first aid equipment in their armor, of course. Carol’s was, except for purely mechanical items like wound dressings, incompatible with Human chemistry. Molly’s seemed inappropriate to the present trouble, but she lacked the medical knowledge to offer more than a guess at her present trouble.

The Shervah could guess equally well, and with more conviction. “I told you it was insane to take that bath. School only knows what was in that part of the river besides water.”

“But I didn’t get any of it in my eyes. I had them shut tightly when I submerged.”

“You didn’t get much of it in your eyes. What’s its vapor pressure at the temperature of that bath? What does it do to your chemistry? How much does it take to destroy your eyes?”

“Since I don’t know what it is…” “Precisely. All right, I’m sorry to overtrack; you know as well as I do how silly it all was—and I know as well as you do that I might have done the same under the same drive. Let’s be reasonable, if you’ve been poisoned by something in that river, the stuff is water soluble. You will have to decide whether you can spare enough water from your armor system, and open your helmet long enough in this environment, to try swabbing your eyes out with a water-soaked dressing. I know it may be too late, and whatever happened will have to run its course; I know whatever caused the trouble may still be around us as vapor. I have wound dressings that will hold water if you decide to try it—so do you, I imagine.”

“I do. Let me think.”

“May I make a point?” It was Joe.

“Of course.”

“If you have suffered chemically from the river, it might be well to get away from the river before you attempt first aid. This will delay your arrival at the hollow and therefore the time when we can get you back to the tent; but this may make little difference, since real treatment probably cannot be started until Classroom with others of your species returns. If you can wait without too much pain, it might be a good idea to hold off opening your helmet until your river has gone, as Charley’s did. Is there very much pain involved, or is it a matter of the inconvenience of not seeing?”

“Mostly the blindness. I can wait, for a while at least. If you can do all the watching for narrow passages and low ceilings, Carrie…”

“I’ll have to do that anyway. I don’t expect just swabbing out will be a cure.”

“It might let normal healing go faster.”

“And it might expose you to another dose that would blind you permanently.” Molly noted with gratitude that her companion refrained from adding anything like “if you aren’t already,” and wondered for a moment whether Charley might cut in with one of his infelicitous remarks. If he were so inclined, Carol gave him no chance. “I can keep alert as well as you, and for a lot longer, and even when 1 have to doze I can still stay on watch after a fashion You know that. We won’t have to stop. You relax—sleep if you can. I’ll tell you if the river disappears, and you can decide then whether you want to try washing your eyes or not. Until then, let me run things, and be thankful it’s your eyes instead of mine. Would you like to have to do the lookout job and face the delay of telling me what to do with the robot every time something came up?”

“Your logic is overwhelming. I am quite delighted.” Molly didn’t care whether Joe got the sarcasm, but rather hoped Carol wouldn’t. If she did, she said nothing.

Charley came through, on private channel.

“I have a lot of Human information in my personal library but can’t get at it until we’re back in electromagnetic range of the boat. A lot of it’s probably medical, and might help. Do you think it will be worthwhile for me to go back now to check it out?”

The offer was tempting. However, the likelihood that Charley had really detailed enough medical material available, even if he had simply transferred whole banks of information unselectively for later browsing, seemed too low to be worth anyone’s time. Molly refused the offer with thanks, not guessing what that would do to confuse further the already undecided Kantrick.

Joe did not hear the offer, of course—the private channels were genuinely private—but the same notion had occurred to him. There was medical data appropriate to all members of the team in the boat, though he knew nothing of Charley’s special collection. He could, with its aid, have set a bone for Molly, Carol, or Jenny, repaired even serious cracks in Charley’s exoskeleton, sewn up or cemented wounds for any of them, treated burns and radiation injury, taken appropriate steps for lack of food or solvent or even air for those who used it; but chemical poisoning was a different game tank. There might be relevant and recognizable information. He might find it quickly enough to be of use. It might involve treatment that Molly and Carol could apply with what they had with them, following directions he could transmit. So he asked Jenny to check for the appropriate information and stayed where he was.

It was far more likely that the real need would be for transportation to the boat. Until Charley reached the interior, the only known way back to the surface was stored in Joe’s mappers; and this meant that Joe could not risk his machine in the tunnels again until the women reached the hollow or were stopped so that he clearly had to go to them. He didn’t like it, but he hung near the inner surface, doing a little very cautious tunnel mapping with his small machines, and otherwise simply waiting.

Charley raced through passages when there was only one way to go, stopped to check wind whenever there was a branch, and groped with his rope flag for appropriate exits when the course led through large caverns. His speed, so much greater than that of Molly and Carol when he had had a river to follow, averaged only a small fraction of its earlier value.

He envied Joe for being already in the hollow, where he could be useful. Joe envied Charley for having something to occupy his attention. Molly envied Carol for being able to see where they were going. Carol envied Jenny for being in the lab getting something practical accomplished.

Jenny, happy as a scientist can be only when the data are falling smoothly into a coherent picture, envied nobody. She made a run-through of the boat’s Human information at Joe’s request, found nothing that seemed relevant, and returned to the real work—properly concerned about her Human friend, but quite clear in mind and conscience that there was nothing more she could do about the matter just then. Joe, or conceivably Charley, would establish physical contact eventually; more effective steps could then be taken. In the meantime, a picture of a tightly coordinated ecology, involving life that seemed to have originated on at least nine different worlds and been interacting here for some unknown length of time, was beginning to emerge. Two fundamentally unrelated forms produced hydrogen peroxide; six contained considerable amounts of hydrazine in their body solvents; and one, with a genetic basis she had never seen or heard of, consumed both, apparently getting its energy by reacting the two to water and nitrogen. At least, this seemed to fit their structures; actual life processes would now have to be checked. Jenny kept happily at work.

“Joe!” Charley’s voice came through the Rimmore’s translator, but failed to catch her attention at first. “I’ve found another river—I think.”

“Why is there doubt?”

“It’s not traveling. I entered a big kame—irregular, over thirty kilometers one way, nearly forty at right angles, and over twenty-five deep—from about the middle of the north side. There was some radar ambiguity from near the top, and I went to check it. There are huge drops of what I suppose must be water just hanging here, drifting around, sometimes coming together and joining. When they do that they start to sink, but before they reach the bottom of the cave, they always break into smaller ones and start up again. It’s sort of river’s end, I’d say—maybe Carol and Molly’s.”

“Possible. Theirs seemed to be larger than your original one, and size would be needed to get that deep against rising hot air. It’s a long way from certain, of course, but maybe you should make another gravity check to see how your depth compares with theirs, and if they aren’t too different, you might wait for a little while anyway. If you can meet them, travel in your machine, especially for Molly, will be a lot better than on theirs.”

“Right. I’ll check.”

Carol chimed in. “You know, if that’s the real limit of the river, whether it’s ours or not, the water or whatever it is ought to be loaded with salts; and if the drops are evaporating all the time and getting fed from above, there ought to be crystals around. Why don’t you check the cave walls for that, too? It would be a pity to wait and do nothing.”

“All right. The laser would give an easy check for dissolved salts; I could boil one of the drops, and if there is solid dust, vaporize it and get a spectrum. I’ll…”

“Charley! DON’T!”

The Rimmore’s grating call was too late; Charley had been acting as he spoke.