Rather to Molly’s surprise—her optimism was suffering another setback—this confidence proved justified and the small woman set out on the opposite leg of her journey. Molly’s presumed path was not within this range, either; and once again back at the robot, Carol had to make a decision.
“You should come back and go out again when we make a mapping robot of the sort Joe suggested. It seems there is a complicated set of caves down there, that the winds change capriciously—or at least that we do not yet know the pattern of their changes—and a real map will be needed” was Jenny’s firm opinion. Joe said nothing; rather to Molly’s surprise, Charley was also silent. She herself did not feel very objective at this point. She very much hoped that Carol would not go back, but for purely Human reasons was embarrassed to say anything.
“I’m staying,” said the Shervah flatly. “There is no way we could map this whole place fast enough to catch up with Molly while she’s moving. If you want to come down yourself with such a machine, Jenny, I’m all for it; but I’m looking for Molly.”
“I agree,” said Joe. “I take it you will ride the robot now all around the cave wall. That place can’t be too big. It would probably be best to leave the rest of the rope where you are now; unwinding it around the circumference of the cavern will accomplish nothing that I can see.”
“Good point,” agreed Carol. “It will be easier riding without it, too; I won’t have to watch out for being caught as it pays out. There, it’s off. Here I go. Any supernatural basis for a decision between left and right?”
No one proffered any, and she set out with no further remarks. There was little said in the boat, either. “Give this one a body that can be ridden comfortably, Joe,” grated Jenny’s voice, to tell Molly all she needed to know what was going on above. She reflected that the wind chart was still being made back at the tent, even if its designer wasn’t there to watch. Poor Joe would get a look at it eventually, and of course she had no way of knowing that until that look was taken, she would be getting deeper and deeper into trouble.
A little rill of liquid, presumably ammonia since the surroundings were too cold for liquid water and much too hot for liquid methane even at this pressure, joined her path from one side and kept her company thereafter, picking up tributaries occasionally until it was a brook half a meter across. The passage she was following had widened gradually until she could see neither roof nor sides, and the wind dropped below her personal detection ability, though the robot still seemed to have an opinion about it. It was still coming from downslope, and the slope itself was getting much steeper; the stream was becoming a series of rapids and even falls of several meters height. She was carried some distance first to one side and then the other of the brook, but the latter never went out of sight. She kept the others informed of all this; Carol acknowledged with interest. They had seen no rivers at any point on the surface.
“Keep your light on and your eyes open for more life!” the Shervah exclaimed. “It certainly ought to be around any liquid. If the passage levels off and there are pools or lakes, be really alert.”
“As alert as I can,” replied the Human. “There’s going to be another trouble before too long, though. I don’t know how much longer I can keep awake; and if the wind isn’t reliable, as it didn’t seem to be in the big cave, any more gaps in my own recollection of where I’ve been could be pretty serious.”
“That was one reason I stayed down here,” replied Carol. “If we could think of a way for you to stop while you slept, things would be much less tense. It would be rather nice if that machine were to jam in a narrow passage for a few hours, wouldn’t it?”
“It found its way around the only narrow passage I’ve seen so far, but I’m all for another,” admitted Molly. “I’ll look for that as well as your life forms; the more I have to think of, the better I can stay awake—I hope.”
“I’ve been about four kilos along this wall so far. It’s hard to believe the cavern wind could have changed so much. It probably means I started the wrong way. I’d be tempted to go back, only for all I know I may be more than halfway around this thing by now. As Jenny said, a real map would be useful. I wish I had some idea what could have made this space; I might be able to make an intelligent guess at its size. On any decent planet, gravity would prevent a cave from getting too big before its roof caved in, but this is not a decent planet. I could almost believe this was a big bubble, maintained by gas pressure.”
“Except,” pointed out Molly, “that there is direct communication with the outside air, and the pressure in here can’t be significantly different.”
“Not even from altitude difference?” asked Joe. “You could really be a kilometer or two down by now.”
“And what difference would even five kilos make with this atmosphere at this temperature in this gravity?” asked Molly, who had had time to do some mental arithmetic since the question had come up earlier.
Joe took a second or two to run through the same figures. “Less than a thousandth of an atmosphere,” he said at last.
“Which would not show on my suit gauge, I’m afraid. If I do get deep enough in this planet to read it there, I’m not sure I want to know it. I’ll be facing a long, long trip back up again.”
“How about a kame?” asked Charley.
“A what? Oh, I remember…”
“A place where a deposit of the ice you’re looking for used to be, but melted or vaporized out, leaving your cave.”
“Where did you learn about that? I didn’t think ammonia behaved that much like ice.”
“I don’t know whether it does. I’ve done a lot of reading about your world since you people showed up. It’s a fantastic place. I can’t get over water’s expanding when it freezes…”
“Neither could Carol when she found how slippery that made it,” Molly remarked drily. “Say, I wonder…”
“Molly! I think I’ve found where you went in!” came Carol’s excited voice. “Wait a bit, I’ll check a few hundred meters around out in the cavern. Yes, your crystal region, and what seem to be your traces are here.”
“About how far did you have to go to find it?” asked Molly.
“I’m estimating about six kilometers.” The others knew that with the combination of depth judgment and memory possessed by the Shervah, this was probably good within ten percent. “That leaves another question. Am I most of the way around the cave, so that it will be quicker to go on for the rope than to go back, or not?”
“We’d better hope you are,” said Joe drily. “If not, the rope is nowhere nearly long enough. With Molly getting farther away all the time, there is already some doubt about its reaching her.”
“Right. I’ll go on.
“Also,” added Carol happily, “that will give us a good chance to find the actual size of this cave and maybe start some reasonable guessing about what formed it.”
This rather barbed implication about Charley’s suggestion was not taken up, even by the Kantrick.
“You’re traveling as you talk, I hope,” remarked Molly.
“Absolutely. I’ve gone about four hundred meters from the narrow end of the crack—the end you didn’t go into—and you will be pleased to know that I remember this part of the cavern. The rope is a kilo farther along. I’ll be with you soon.”
“You mean if you’d gone only a little farther to the right on your original foot search, you’d have saved an hour or so?” asked Charley.
“You seem to have the picture. If Joe hasn’t tied up all the tools, you might start some more rope in the shop while you’re waiting. Jenny must have filed the specs. I hope we won’t need it, but I certainly can’t promise we won’t.”