by Hal Clement
“You tell Joe how I’m doing, then—and me as well. I get less wind trouble if I stay mostly buried, and that keeps me from seeing very far. Let me know when I’m near the top.”
“All right. Don’t bury yourself entirely.”
During the next few minutes, only Charley’s terse remarks connected the group. “You’re about halfway.” “You’re digging in too deeply—I can hardly see you.” “Are you following the rope? You seem to be working around to the other side of the hill.” “You’re getting buried again.”
“I can’t help it,” Jenny replied to the last comment. “I’m not digging in; the hill is traveling like a dune, I think. The wind is trying to move it on top of me.”
“Are you sure?” cut in Joe.
“Not sure, but it’s the impression I get. Why?”
“Never mind.” The Nethneen fell silent again.
“I hadn’t noticed that the hill seemed any closer,” said Charley thoughtfully, “but that would explain why the rope seems to be leading you around to the other side.”
“So it—Oh! I get it! Joe! Nearly done?”
“Nearly. Get to the top as quickly as you can and report what, if anything, is left of the crater. Stay there as long as you can. Charley, get distance measures of her as exactly as possible at regular intervals after she gets to the top; we may want to know how fast that hill is traveling. Jenny, just do your best to stay on the crater rim, if there still is one, until I get to you. Carol? Molly?”
“Yes.” It was the Human’s voice.
“I take it you have not found your entry tunnel and that there is no wind to guide you.”
“Plenty of wind. It led us to the wrong tunnel, which was blocked with vegetation—to classify hastily—before we got far anyway. We’ve gone back to the big cave and are checking its walls at this height for the right opening.”
“How did you know it was the wrong tunnel?”
“We were pretty sure from the beginning because it was a lot lower than we thought it should be.” It was Carol’s voice this time. “Then it became a narrow, twisty tube of rock that finally got too narrow for the robot.”
“Why didn’t you tell us?” asked Charley.
“What could you have done about it? As long as we could get back to the big cave, there was nothing to worry about. It cost us only a few minutes, anyway. But, Joe—is there any point in trying to find the original tunnel now?”
“Possibly not, but what happened to your rope may still be useful data, and your memory will give us information on how much of the way is blocked.”
“What are you talking about?” asked Charley.
“Their guiding wind has stopped. Your hill is a moving dune. They don’t hear the storm any more. Jenny, are you at the top yet?”
“Nearly, I think. Charley, can you see me?”
“Yes, barely. Ten meters or so will bring you to the lip, as far as I can tell. I see what you mean now, Joe. But look—if they have a different wind, there must be other openings to the surface, even though this one may be blocked; and maybe we could dig through this sand…”
“That’s why I want to have Carol check the inside and Jenny the out. It’s too bad Jenny never saw the crater as it was before, but—wait; you did, Charley. Lift the boat and get a look into that hole yourself. Stay close to Jenny—you don’t want to pick her up by her safety line. You can let down and collect her when you’ve checked the crater, unless it looks as though digging were going to be quick and easy and she wants to start in at it.”
“I doubt that it will be” came the Rimmore’s rasp. “The hole I can see now is less than half as deep as the hill looks high from outside. That’s not what I remember the rest of you saying. I have no digging tools, anyway.”
“Any luck from inside, Molly and Carol?” asked the Nethneen.
“Four holes that might be tunnel openings so far, all of them different in detail from the one we came through, none of them with any air currents, and each with different kinds of stuff growing in it” was the Shervah’s answer. “We’ll keep looking, but more for wind than for similarity. I’m beginning to guess what happened to the rope. Are you up where you can see the crater yet, Charley?”
“Just a moment. Yes. I was a little too high; this wind is increasing, or at least the visibility is getting worse. The hole is half full. Stay where you are, Jenny; I’ll bring the boat down where you can reach it. You still have your own safety line, don’t you?”
“Of course. It’s fastened at the main personnel lock. Turn a quarter left—now straight down—ten meters to the right and about three aft—another two to the right—there. I have the lock open—I’m inside—outer door is closed, and I’m flushing the local air. You can do what seems good with the boat. Is the new machine ready, Joe?”
“Yes, but I’m not quite sure what we do with it now. Carol and Molly are blocked from us. We have no high-powered excavation equipment other than ordinary explosives, which it would be unsafe to use—for all we know of the local structure, we might bring the caverns down on them. We…”
“Pardon me, Joe” came Molly’s voice. “I think there is a pretty clear line of action. Since there are winds down here—we’ve found another, much fainter current and are following it—there must be other connections with the surface. I think you’d better get back to your air-current maps, maybe concentrating on the local area more than you would have done, and see how many passages you can find with winds blowing out and with winds blowing in. At the moment, Carol and I really have no basis for a guess on whether we should go upwind or down. Back to your wind maps, little friend!”
“Which were you doing with that current that led you into a narrow passage?” asked Charley.
“Downwind. The only evidence we had at the time was that we’d come in against the wind.”
“When its path got too narrow, did you backtrack?”
“Obviously.” Carol’s voice was a trifle impatient again.
“I mean past the point where you first found the current? I got the impression you went looking right away for other winds.”
“Oh. Yes, that’s right. We don’t know where that one came from.”
“Then you have at least one more lead if the one you’re using now proves useless.”
“I suppose we do. I suspect we have several hundred. What we really need is for Joe to find an incurrent passage and flood it with something nice and smelly that we could follow to its source.”
“You’re not going to take your helmets off to smell the air.”
“I’m afraid not,” agreed Molly before Carol could counter. “Even if I risked an occasional sniff, I don’t suppose I could catch anything but ammonia—which probably doesn’t have any odor to the rest of you.”
“Actually, the idea has some merit,” Carol pointed out. “The robots can do a certain amount of gas analysis, can’t they, Joe? We might keep it in mind, if the right conditions arise. Anyway, I second Molly’s motion. Back to your maps.”
“I have a further suggestion,” said Jenny. “In addition to the normal mapping, two of us could search the area for caves leading underground. Charley could use the boat and I the new mapping robot Joe has just finished. With this storm, vision won’t be much help right around here, but we could head upwind to its edge and cover the topography in detail as it moves, following it back in this direction. We can map any promising places, and even if they seem too far from you to be very helpful yet, just getting an idea of their number and distribution should be of use.”
“Joe!” Carol snapped suddenly. “The robot just stopped!”
“What was guiding it? Did you see or hear anything change?”
“We were following another air current, as I said…” “Up- or downwind?”
“Down. It must have stopped. There’s roaring ahead—I’m not sure what’s happening…”
“The storm? You weren’t hearing that before. Maybe you’ve gotten close enough to an opening to outside…”
>
“It wouldn’t have been that sudden, Charley. Molly, can you see anything ahead? Use any kind of light you want—I’ll cover my eyes with the regular flare lids.”
“Nothing. The passage just goes on. But the racket is getting louder—back the way we came, Carrie! As fast as we can travel! It may not be falling rock, but I can’t think of anything else that might sound anything like it. Move this thing!”
“You mean the tunnel is collapsing?” cried Jenny.
“I don’t know. Not close enough to here for us to see, but that would explain the wind’s stopping. Get back to the big cavern, at least, Carol, and do some more checking on its wind patterns—let’s see whether the ones we found earlier still exist. If the structure of this labyrinth is changing much ...” Molly left the sentence unfinished, and none of the others tried to complete it. There were several minutes of silence. The people in the boat could think of nothing useful to do, and even Charley was afraid of distracting the fleeing couple with a badly timed question. The boat, indifferent to the wind, hovered above the rapidly filling crater where the women had vanished. Its occupants could only listen to their translators.
“Back in the big place.” Carol’s voice came at last.
“Can you still hear the falling rock, if that’s what it was?”
“No, Joe; that faded out within a few seconds. Whether we got away from it or it just stopped I don’t plan to find out. I can’t hear it, or the storm, or anything but your voices. You, Molly?”
The Human shook her head negatively, then remembered that only Carol could see her. “Nothing.”
“What next? Search this level for more tunnels?”
“I don’t think so. I say back down to the lake, or whatever it should be called, and find that passage we went along earlier. It had a wind, remember—so did the one you started into. Let’s see whether those are still blowing. I’m beginning to think we’d be best off going upwind looking for places where air currents go underground.”
“Why?”
“Well…”
“Going upwind is most likely to find your ice, isn’t it, Molly?” Jenny’s voice carried amusement.
“I hadn’t thought about ice for a couple of hours at least,” the Human replied, not even blushing. “It would be interesting to find it but wouldn’t get us out of here. Right now I’m beginning to doubt that there is any.”
“What?” This was Charley, of course. “You know the density of this planet as well as I do and have seen even more of the rock it’s made of. It can’t be all silicate—there must be hydrides.”
“That’s the logic,” Molly agreed.
“Well, where’s the hole in it? Don’t you believe it any more?”
“There’s a healthy doubt growing. This place could be a sponge rather than an iceberg. In any case, with no ice vaporizing, air would have to be blowing in to match what blows out, and we should have as good a chance going upwind as down—especially since two downwind searches have failed us now.”
“Three, if you count the hunt for the original entry,” pointed out Carol.
“All right, three.”
“But going upstream, a river tends to subdivide into smaller and smaller streams,” Charley pointed out. “Downstream it gets bigger. I’d think…”
“This isn’t a river, which cuts its own path,” Carol interrupted. “We don’t know what made this labyrinth, and so far we’ve observed only one of its surface connections. Frankly, I’d rather be moving. There was a river in the other tunnel, and maybe it will give some guidance. The only other thing we have is wind; the only choices we have are with or against, and I’m with Molly for the moment—let’s try against, as fast as the machine will take us.”
“How about recovering the other robot?” Carol thought for a moment.
“If you can put up with its loss, Joe, I think I’d rather not commit myself to an endless running back and forth keeping the two together, even if we are near the ground most or all of the time. If a sudden drop takes us by surprise, the way it did Molly awhile ago, it might be hard to get back together. I think it would be best if we rode the same machine, however uncomfortable.”
“If you think that’s safest, do it that way. We can replace robots. Go ahead as you suggest. We’ll follow, as nearly overhead as we can, in the boat as long as there is any contact with the one you’re riding.” The women agreed briefly, and Carol sent their mount downward more rapidly than she had risked up to this point.
Molly kept her light beamed below and gave warning as the liquid surface approached. They were out of sight of the cavern wall, and not even the Shervah was precisely sure of direction, but she sent the cylinder quickly in what she hoped was more or less the right one.
It took two or three minutes to reach the edge of the lake, grown thicker with the grass here; Molly wondered whether time or location had made the difference. The arrival brought no relief.
“Joe! Charley! The level is higher! There’s no place along the edge to travel now. It’s right against the cave wall and partway up—I can’t tell how far.”
“About three meters since we were last here. The passages we used—yours and mine both—are off to the right,” Carol interjected.
“How far?”
“Yours, about seven hundred meters. We’d better hurry.” “Why?”
“Do you want to ride, swim, or get washed down that passage?”
“I’m not sure I want to go along it at all now.” “You’d rather wait until this place fills with ammonia?” “It couldn’t!”
“I’d like to believe that, too. Where’s the stuff coming from? How big is the source? Maybe it’s going to keep raining into the lakes in this neighborhood for the next twenty years. Maybe one of the lakes up above is draining into these caves.”
“But…”
“Come.” Carol said only the one word, and Molly regained her self-control. Of course her little friend was right.
Unless the ammonia turned out to be coming in from below ...
Carol sent the robot on.
Chapter Sixteen
Of Course He’d Fail
“What if the passage you’re looking for is already full of ammonia?” Charley asked anxiously.
“I don’t see how it could be.” Molly comforted him and herself. “There’s a lot of space—I have no idea how much, but I’m almost sure it’s more than this cavern here, judging by my own wanderings—to fill once it starts overflowing that way. The stream should be flowing again, though; maybe that will be some sort of guide.” “Not to the surface!”
“Well, no. But at least this particular place would have to be filling very fast indeed to cover that opening completely. We don’t have to worry about being able to get into it, I’d guess.”
“You mean you’ll go down that passage, away from the surface, in spite of…”
“Unless,” snapped Carol, “you can tell us that the storm up there, which is blowing sand fast enough to block our original entrance with a mountain-sized dune and apparently precipitating enough liquid to fill sizable caverns, is either a very small one or is about to end, yes. We are going down that passage if there is wind coming out of it. If not, we will go down any other passage we can find wind coming out of. I can’t see anything else to do. If this idiotic ball of salt kept its surface features from one century to the next—at least we can see why there was no way to match our maps with the old ones—or had a magnetic field strong enough for an ordinary person to feel, or Joe had provided some way for a person riding this robot to read its inertial sensor…”
“I did, in the new one.” An interruption by Joe was so startling that even Carol, playing straighten-out-Charley, was silenced for a moment.
Her attention shifted. “Good. Thanks. We’ll still have to use air currents for a guide, though, and following rivers upstream doesn’t seem very promising, as Charley pointed out awhile ago. For one thing, if this turns into a real river, it will probably have started out at the top from s
eepage; and I’m not that small. I also think we’ll have to drop this policy of keeping the robot down to a speed we can catch on foot. We don’t know how far we’ll have to go.” “But if one of you falls off…”
“If Molly falls off, I can stop the thing and wait or go back for her. If I—I’d better not.”
“I still have some surplus water,” Molly said thoughtfully. “I’d rather not use it for glazing robots, of course. But maybe we could rig some kind of gadget that would let me stop the thing with a single key—I know the controls well enough; it’s just that my hand is too big to get at them, even if I take off a glove and risk freezing my skin to the metal. All I really need is a piece of stiff wire about twenty centimeters long. I can see in as long as my light’s working—at least the keyboard faces the opening in the body! That’s luck. With Joe’s tendrils, it didn’t really have to. Sorry, Joe; that was unkind.”
“Deserved, I fear. On a less painful note, what do you have in your armor or equipment that will let you reach the keys?”
“Until I figure that out, we’ll keep multiple safety lines attached to Carol. Here comes the tunnel, doesn’t it, Carrie?”
“Yes. This lake’s draining into it, as you thought it might. We can get in at the farther side, where the opening is high enough for the robot, and see how full the stream is…”
“And whether there is any wind!” exclaimed Charley.
“And whether there is any wind,” admitted the Shervah. “That first, actually. You’ll have to duck more than I will, big friend; here it comes.”
Charley, far above, waited tensely. He could not picture clearly how close the women would have to come to the flood he imagined spilling down into Enigma’s bowels and was visualizing the worst. His faith that none of them, especially Molly, could be in real physical danger was eroding u trifle, to his own surprise, though he considered the underlying theory still valid. He continued to expect that the Human would report a new situation at any moment now, which would further complicate the group’s assigned test, but he was finding it harder and harder to feel sure that this was all that would happen. He wished briefly that he could see, or even hear, directly what was going on so far below, instead of getting everything via translators.
