“I should have paid more attention to the programs in these things. What will they do if they can’t go forward?” “How can that happen?”
“Meaning you didn’t consider it in the program. The wind is coming through a horizontal crack that seems to start thirty or forty meters to my left and is about thirty centimeters high at the point I’m approaching. It continues to get higher to my right, as far as my light will let me see. This machine won’t fit into a crack of this height. It’s going to run into the rock and stop, and either the controls are going to do something about the situation, or something is going to break. Which will it be, Joe?”
The Nethneen was silent for a number of seconds, and Molly resumed her report.
“About ten meters to go. Should I get off? Will anything burn out if it tries to push the planet out of the way? This machine has a fusion unit in it, after all.”
“No. It won’t push hard enough to damage its drive or its shell; that’s basic to the control system, and I had nothing to do with it,” the little being finally said. “Nothing should burn out, blow up, or break. I’ll have to think out whether being held motionless will be treated like an eddy—let’s see—it can’t count the number of times around, obviously…”
“Contact,” reported the Human. Silence followed.
“If you’re just staying there, I’ll be able to catch you that much quicker,” Carol had time to say.
“I’m not. It’s going to the right, just scraping against the wall. That’s the way the crack is getting wider. If that continues, the machine will fit in pretty soon and I’ll be scraped off the top. Why is it doing this, Joe?”
“At the moment, I have no idea. Please keep reporting.”
“What’s the rock like?” asked Carol. “Is the crack a fault, or an erosion product, or what?”
“I wouldn’t know even if I could see it better, I’m afraid. Obviously wind goes through it; if that ever carries sand, it would explain any amount of erosion. I haven’t seen any liquid yet. The top of the crack is nearly up to the top of the robot; the bottom has been a continuation of the cave floor all along, not that that makes it very level. I’m getting off and following on foot. If the thing does go in, I can too, though not very comfortably. The top rises rather suddenly to nearly my own height, about eight or ten meters ahead, and then levels off, and then the crack comes to an end as far as I can see. It would be nice if your mystery controller showed enough liking for a Human to go over to that point before going in, Joe.”
“I don’t see why it should—nothing personal, of course—but then I don’t see why it’s doing this anyway. If it goes to the high part—hmmm. Let’s see.”
“Don’t start calculating yet. That’s not even a hypothesis, dear colleague. Wait.”
“For how long?”
“Ten ... five, four, three, two, sorry—speed not as constant as I thought. Wall’s curved. We’re there, and it’s going in. I don’t like the idea, but I guess I’d better follow.”
“Wouldn’t it be wiser to wait for me?” asked Carol.
“If there were no doubt that you’d avoid all trouble on the way, and I suppose it is a pretty safe bet, yes. However, if you don’t get here—if you run out of rope because measures were off, or your robot doesn’t follow the same track as this one because the underground winds aren’t as steady as we’re hoping, or something none of us has thought of yet—then I’d better stay in reach of that machine. My armor has battery power for a few days—just how long depends on what it has to do in the way of temperature control—but any longer and I’ll have to recharge. The robot has a fuser, and I can plug into the slave feeder on the top. That machine could be air, food, and drink to me for months, much as I hate the thought of being in here anything like that long.”
“You’re not really serious about that, are you?” Charley’s tone was as protesting as his choice of words.
“Very serious about not wanting it. I consider the possibility too serious to ignore. I’m staying with the machine until Carol catches me, though I’m nearly certain that she will. I’m not going to report for a while, unless it’s something urgent. I’m still connected by rope, but this passage isn’t quite high enough for real walking, and even in this gravity I don’t want my armor to be dragged.”
“If you have a chance to turn your light to both sides, Molly, you might tell me something about the shape of the passage you’re in. I know where you entered it was higher than it had previously been; the portion passed, which I judge is now to your left, was at that time lower. Might I hazard a guess that you are now under a rather low roof and that it gets higher to your left, and that there is very little of the passage at all to your right?”
“Wait a minute. If you’re right, I could go to my left and stand up, which would be a relief—all right, you diminutive genius, how did you work that one out?”
“I claim no more than a guess—there probably was, and remains, a vast number of possibilities that have not yet occurred to me. However, there must have been a small wind component, or a pressure effect that the robot would interpret as one, to the right along the cave wall outside, or it would not have traveled in that direction. If the outward wind speed was higher where the crack was low and decreasing as you went along, Bernoulli effect would produce a slightly lower pressure on the left of the robot as you faced the wall. To have such a velocity change, there should be a relatively large chamber or passage beyond the crack. There were really too many possible variables. I repeat, it was a guess, and I should prefer not to make another such.”
Joe, the women knew, was genuinely embarrassed; Charley might have been less aware of his colleague’s feelings, but even he recognized that it was better to let the subject drop.
“Carol,” called the Kantrick, “have you reached that long drop yet?”
“Almost at its edge. I was just going to call you so Joe could check his timing. I’m over emptiness ... now!” “Any trouble with the rope?”
“None. We should have thought to provide some regular marking system along it, so that a really good measurement of distance could be obtained.”
“Welcome to the club!” came three voices.
“It would have added some time to that needed for making it, though,” added Jenny.
“I suspect even Molly, at the wrong end of the road, would admit that it would have been time well spent,” retorted the little planetologist. “Wouldn’t you, big friend?”
The Human’s answer was affirmative, but possibly not as immediate or enthusiastic as the Shervah would have liked. Joe was the one to alter the subject this time.
“I’m losing touch with your robot, too, Carol. I have been getting the same sort of depth measurements by triangulation that I did with Molly and feel quite sure that the uncertainties are due to the rock effects. If we really want to map your underground regions, we’ll have to make a new robot with a really good inertial system equipped to integrate its readings.”
“Fine! Let’s do it, as soon as Molly’s out of trouble!” exclaimed Jenny.
“Remember, friends—wind maps!” called Molly softly. “We have plans, which are already somewhat out of shape, and we have only so much time before Classroom gets back.”
“If we get something really new, as you seem to hope, Molly, maybe we could stay here longer; they could fit Eighty-eight into the next run, I should think, without too much trouble, and pick us up then.”
“We’d better not plan on it, Charley,” replied the Human, “though I agree it’s a tempting idea. My impression is that Classroom is scheduled years ahead, and making a change would have an avalanche effect on other schedules. What we really need is a breakthrough—something that will convince the Faculty that this isn’t just a matter of adding trivial details to a picture whose outline is known. That might persuade them to arrange a special investigator of its own for Enigma. Unfortunately, we don’t know that we have one here. I’d like to believe that sort of thing could happen, but I’m not conceited enough to expect that I’ll be the one to do it.”