Close to Critical

by Hal Clement

  “I’m afraid I’ve been a trifle negligent with your education,” remarked Raeker, “though I suppose the rather ambiguous nature of most of this planet’s liquid gives me some sort of excuse for leaving out Archimedes’ Principle. Try it again, Nick, and this time put a couple of stones in the bucket first.”

  As might have been expected anywhere on Tenebra except the actively orogenic regions, there were no loose stones in the neighborhood; but by packing the bottom third of the container with broken-off shrubbery, Nick contrived to achieve the spirit of the Teacher’s order. This time the bucket floated almost upright, and with a good deal of freeboard.

  “See how much more you can put in it before it sinks,” said Raeker. Nick obeyed, without asking for the meaning of the new verb; it was clear enough from context. To his unconcealed astonishment, it proved possible to fill the bucket with the brittle growths without actually forcing it under, though a ripple half an inch high would have accomplished this end—a fact Raeker at once proceeded to demonstrate. At his order, Nick splashed vigorously in the pool with his feet; waves curled over the edge of the bucket, and it sank almost at once.

  “Do you think it would be possible to make something on that general line, capable of keeping several people from sinking?” asked Raeker.

  Nick wasn’t sure. “Just on the face of things, I’d say yes,” he replied, “but I don’t really see why that works at all. If I knew, I could answer more sensibly. What use would it be if we had such a thing?”

  Raeker took this opportunity to give a rapid explanation of Archimedes’ Principle, plus an account of Easy’s reports, mentioning the brief appearance of the cave scout and concluding with the probability that the bathyscaphe had reached the sea. Nick could see the rest of the situation for himself, and, characteristically, went a trifle overboard in his enthusiasm.

  “I see!” he exclaimed. “The ship is in the ocean where no one can get at it, so you’ve showed us how to travel on the ocean itself. We could get out to the ship with this big bucket you want us to make, and pull the ship along with us to the other side, where Swift wouldn’t bother us. It’s a good idea. We’ll start making the bucket as soon as the others come back—in fact, we can start collecting leather for it right now—”

  “Hold up a minute, Nick. Crossing oceans, even oceans as small as Tenebra probably has, isn’t something you do quite that casually. Also, there’s another point to be considered. What if you were out in this—this bucket at night?”

  Nick thought briefly. “Why couldn’t we carry firewood and torches?”

  “You could; but that’s not the point. What happens to the ocean at night?”

  “It conies up; but wouldn’t the bucket go up with it?”

  “I’m afraid not. In going up, the ocean decreases enormously in density, and I’m afraid that rather early in the evening you’d find it oozing over the side of your bucket—and you saw what happened just now when the same thing occurred here in front of us.”

  “Yes,” admitted Nick thoughtfully. He was silent for a time. Then he became enthusiastic again. “Wait a minute. The bucket sinks because liquid gets into it, and it is no longer lighter than the liquid it displaces—right?”

  “That’s right.”

  “Suppose, then, that instead of a bucket we have a closed bag of air? If it’s tied shut the sea can’t get in, no matter how much it rises.”

  “But if the sea becomes no more dense than the air?”

  “At least when the water boils out of the sea in the morning the bag will float once more.”

  “All that is true only if your bag doesn’t leak at all. I’d rather you didn’t risk your lives by staying at sea during the night, though your idea of bags rather than buckets is a good one. It would be smart to make a ship of many bags tied together, so that if some of them do leak you will still float.”

  “That’s plain enough. But why shouldn’t we stay out at night? What if night falls before we get the ship across the ocean.”

  “You won’t cross the ocean. You’ll work on it during the daytime, and come ashore again at night.”

  “But how about Swift?”

  “I’ll take care of him. Don’t you plan to keep the agreement we offered to make with him?”

  Nick thought for a moment. “I suppose so, if he really agrees. If that was one of his scouts who found the ship last night, maybe he just decided to find it for himself.”

  “I still think that find was sheer chance. If it should turn out that you’re right, we’ll solve that one when we face it. Easy is willing to face Swift, she says. Right, young lady?”

  “Certainly.”

  “Do you like Swift?” Nick asked her in some surprise. “I can’t forget that he killed two of my friends.”

  “I’ve never met him,” Easy pointed out. “I admit it was bad for him to attack your village that way, but probably he couldn’t think of any other way to get what he wanted. If you’re smart, Nick, I’ll bet you could have him doing just what you want—and make him think it’s his own idea all the time.”

  “I never heard of such a thing!” exclaimed Nick.

  “Well, listen in if Swift finds us again,” replied the girl, with a confident tone that surprised even her father. “You’ll learn something.”

  Rich signed to Raeker to cut off his transmitter for a moment, and made a comment. “I hope that young squirt isn’t getting too cocky. I admit she’s giving Nick just what I’ve given her on and off all her life; I just hope she’s up to it if the occasion arises. That Swift isn’t human, or Drommian either!”

  Raeker shrugged. “I’m hoping she won’t have to try. In the meantime, I’d much rather have her confident than scared senseless.”

  “I suppose you’re right.” Rich looked at the screen, where his daughter’s confident expression glowed as she enlarged on her theme to the surprised and still doubtful Nick. Raeker listened with amusement for a while, but finally suggested tactfully that she tell him something about boat-building; Nick knew even less about that than he did about diplomacy, and was more likely to need the information. Easy was perfectly willing to change the subject as long as she could keep talking.

  Presently ’Mina, who had kept faithfully to his watchman’s duties at one of the windows, called to her with the information that he thought he could see the surface. Easy broke off and left the control room hastily, calling back after a moment that her young friend seemed to be right. It was not until the upper observation windows of the bathyscaphe had actually emerged into the “air” that Raeker remembered something; he had missed an opportunity to check on the mysterious sea life originally reported by Nick. Aminadorneldo had made no mention of any such creatures during his last period of watch, but Raeker didn’t know the young Drommian well enough to feel sure he’d have reported them without special instructions. This was obviously not the time to ask; Easy’s eager tongue was busy with more up-to-date reports.

  “We’re farther out to sea than you thought we would be, Dr. Raeker,” she called. “I can just barely see the shore, at the very limit of our hottest lights. I can’t make out any details, really; but I think maybe there are some points, or maybe islands, sticking out our way.”

  “Can ’Mina see anything more?”

  “He says not,” came Easy’s answer after a brief pause. “He doesn’t seem to see quite as well as I do, anyway, I’ve noticed.”

  “I see. I suppose you can’t tell whether you’re moving or not.”

  “The ocean is perfectly smooth, and there aren’t any waves around us. There’s nothing to tell by. The only things to see are those big jellyfish things floating in the air. They’re moving slowly in different directions, more of them toward shore than away from it, I think. Let me watch them for a minute.” It was considerably more than a minute before she could make up her mind that the first impression had been right. Even then she admitted willingly enough that this was not evidence of the bathyscaphe’s motion.

  “All rig
ht,” said Raeker when this had been settled. “Just keep an occasional eye on the ocean to make sure nothing happens, and give advice to Nick as long as he’ll listen to you. He’ll do what he and Betsey can about it, but that won’t be much before the others get back. They’ll probably be gone until tomorrow night, Tenebra time— between five and six days on your clock.”

  “All right, Doctor. We’ll be fine. It’s rather fun watching those flying jellyfish.” Raeker opened his mike switch and settled back thoughtfully, and with some satisfaction. Everything seemed to be progressing properly; perhaps somewhat more slowly than he would have liked, but as rapidly as could reasonably be hoped. This feeling must have showed on his face, for his thoughts were read quite accurately.

  “Pleased with yourself, I take it, Man!” The speaker did not need to introduce himself. Raeker endeavored to control both his features and his feelings, with questionable success.

  “Not exactly, Councillor—”

  “Why not exactly?” shrilled Aminadabarlee. “Why should you feel any remote sense of satisfaction? Have you accomplished anything at all?”

  “I think so,” Raeker answered in some surprise. “We know very nearly where your boy is, and we should have a rescue team out there in a week or ten days—”

  “A week or ten days! And then you’ll have to give the team members degrees in electrical engineering, and then hope the wiring of that ridiculous craft hasn’t corroded beyond repair in the interval. How long do you think the actual rescue will take?”

  “I’m afraid I couldn’t hazard a guess,” Raeker answered as mildly as he could. “As you point out so clearly, we don’t know how much damage may have been done to wiring exposed by the inspection ports. I realize that it is hard to wait, but they’ve been getting on all right for a month now—”

  “How stupid can even a human being get?” asked the Drommian of the world at large. “You were talking to the ground just now, and heard as clearly as I did the human child’s remark that my son didn’t see as well as she did.”

  “I heard it, but I’m afraid the significance escaped me,” admitted the man.

  “Drommian eyesight is as good and acute as that of human beings, if not better, and my son’s has always been normal for his age. If he can’t see as well as the human with him, something’s wrong; and my guess is that the low oxygen concentration is affecting him. I gather your engineers made no particular provision for altering that factor of the vessel’s environment.”

  “They probably didn’t, since the crew was to be human,” admitted Raeker. “I did not recognize the emergency, I must admit, Councillor; I’ll try to find means of speeding up the operation—for example, I can probably get pictures of the wiring exposed by the ports from the engineers, and have Nick briefed on what to look for while he’s waiting for the others. My relief is due in half an hour; as a matter of fact, he’d probably be willing to come now if I called him. Have you been able to get medical advice from Dromm yet? I understand a human doctor arrived a few hours ago, and has been finding out what he can about the diet available on the bathyscaphe.”

  “Eta Cassiopeia is half a parsec farther from here, and I did not get a message off quite so quickly,” admitted the Drommian. “One should be here shortly, however.”

  Raeker felt that he had made a smart move in forcing the nonhuman to make such an admission; unfortunately, admitting mistakes under pressure does not improve the temper of the average human being, and Aminadabarlee’s race was quite human in this respect. He could not be insultingly superior for the moment; even his standards prevented that; but the required repression of choler was a good deal more dangerous to peace than his usual superciliousness. He retired to his own room—which the “incompetent” human engineers had at least set up with a decent atmosphere—and brooded darkly. There were many more message torpedoes.

  With the Drommian gone, Raeker decided not to bring his relief on too early; but as soon as the fellow did show up, he made his way to the engineering section and outlined the proposal he had made on the spur of the moment to Aminadabarlee. Sakiiro and his colleagues agreed that it was worth trying, and they all settled down with their blueprints to decide what would be the best things to tell Nick and the easiest way to get the information across.

  They spent some hours at this. Then Raeker went to eat, and back to his own room to sleep for a few hours. When he reappeared in the observation room, his relief rose gladly.

  “Easy has something to report,” he Said, “but she wants to tell you personally.” Raeker raised his eyebrows, dived into his station, and energized the microphone.

  “I’m here, Easy,” he said. “What’s happened?”

  “I thought I’d better tell you, since you’re the one who said we’d stay put,” the girl responded at once. “We’ve been drifting closer to shore for five or six hours now.”

  Raeker smiled. “Are you sure the shore isn’t just getting closer to you?” he asked. “Remember, the sea level had a long way to go down even after you got to the surface.”

  “I’m quite sure. We’ve been able to keep our eyes on one piece of shore, and the sea has stayed right by it while we got closer. It has a feature which makes it easy to recognize, though we weren’t able to make out very clearly just what the feature was until now.”

  “What is it?” asked Raeker, seeing that he was expected to.

  Easy looked at him with the expression children reserve for adults who have made a bad mistake.

  “It’s a crowd of about fifty natives,” she said.

  X. COMPREHENSION; CONSTRUCTION; INUNDATION

  Nick, for the hundredth time, looked toward the ocean and fumed. He couldn’t see it, of course; to be out of its reach by night the camp had had to be placed well out of its sight by day, but he knew it was there. He wanted to see it, though; not only to see it but to ride on it. To explore it. To map it. That last idea presented a problem which occupied his mind for some time before he dropped it. Fagin would know the answer; in the meantime there was a boat to be built. That was the real annoyance. Nothing, really, could be done about that until the search teams got back. While it didn’t actually take all of his and Betsey’s time to watch the herd and gather firewood, neither could do any very effective hunting with those jobs in the background; and the boat was very obviously going to take a lot of skins.

  Nick wasn’t sure just how many, and to his surprise Fagin had refused to offer even a guess. This was actually reasonable, since Raeker, who was not a physicist, was ignorant of the precise densities of Tenebra’s oceans and atmosphere, the volume of the average leather sack which might be used in the proposed boat, and even the weight of his pupils. He had told Nick to find out for himself, a remark which he had made quite frequently during the process of educating his agents.

  Even this, however, called for a little hunting, since it seemed a poor idea to sacrifice one of the herd to the experiment. Betsey was now scouring the surrounding valleys in the hope of finding something big enough to serve—the floaters of the vicinity had already learned to leave herd and herders alone, and those killed or grounded in the process had long since been disposed of by scavengers. Besides, their skins were much too frail to make good leather.

  There was no serious doubt that Betsey would find a skin, of course, but Nick wished she’d be quicker about it. Patience was not one of his strong points, as even Easy had already noticed.

  He was a little mollified when she came; she had brought not only the kill, but the skin already removed and scaled—a job which Nick didn’t mind doing himself, but it was at least that much less tune spent before the actual experiment. Betsey had kept in mind the purpose to which the skin was to be put, and had removed it with a minimum of cutting; but some work was still needed to make a reasonably liquid-tight sack. It took a while to prepare the glue, though not so long for it to dry—strictly speaking, the stuff didn’t dry at all, but formed at once a reasonably tenacious bond between layers of materials such as lea
ves or skin. Eventually the thing was completed to their satisfaction and carried down to the pool where the bucket had floated a few hours before.

  Nick tossed it in and was not in the least surprised to see that it, too, floated; that was not the point of the experiment. For that, he waded hi himself and tried to climb onto the half-submerged sack.

  The results didn’t strike either Nick or Betsey as exactly funny, but when Raeker heard the story later he regretted deeply not having watched the experiment. Nick had a naturally good sense of balance, having spent his life on a high-gravity world where the ground underfoot was frequently quite unstable; but in matching reflexes with the bobbing sack of air he was badly outclassed. The thing refused to stay under him, no matter what ingenious patterns he devised for his eight limbs to enable them to control it. Time and again he splashed helplessly into the pool, which fortunately came only up to his middle. A ten-year-old trying to sit on a floating beach ball would have gone through similar antics.

  It was some time before anything constructive came of the experiment, since each time Nick fell into the pool he became that much more annoyed and determined to succeed in the balancing act. Only after many tries did he pause and devote some really constructive thought to the problem. Then, since he was not particularly stupid and did have some understanding of the forces involved— Raeker felt he had not been a complete failure as a teacher —he finally developed a solution. At his instruction, Betsey waded into the pool to the other side of the sack and reached across it to hold hands with him. Then, carefully acting simultaneously, they eased the weight from their feet. They managed to keep close enough together to get all the members concerned off the bottom of the pool for a moment, but this unfortunately demonstrated rather clearly that the sack was not able to support both of them.

  Getting their crests back into the air, they waded ashore, Nick bringing the bag with him. “I still don’t know how many of these we’re going to need, but it’s obviously a lot,” he remarked. “I suppose six of us will go, and two stay with the herd, the way the Teacher arranged it this time. I guess the best we can do until the others get back is hunt and make more of these things.”