"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 144 CLOSE TO CRITICAL.

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 emer- gency, 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 Ca.s.siopeia is half a pa.r.s.ec 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 Deduction; Education; Experimentation 145 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 sh.o.r.e for five or six hours now."

Raeker smiled. "Are you sure the sh.o.r.e 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 sh.o.r.e, 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. f.a.gin 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 f.a.gin 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 .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 146 Comprehension; Construction; Inundation 147 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 leaves 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 outcla.s.sed. The 148 CLOSE TO CRITICAL.

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 ash.o.r.e, 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."

"There's another problem," Betsey pointed out. "We're going to have quite a time doing whatever job it is f.a.gin wants done while trying to stand on one or more of these sacks. We'd better pay some attention to stability as well as support."

"That's true enough," Nick said. "Maybe now that we've done some experimenting, the Teacher will be will- Comprehension; Construction; Inundation 149 ing to give us a little more information. If he doesn't, there's that other person whose voice he sends us- the one he says is in this ship we're to look for- By the way, Bets, I've had an idea. You know, he's been explaining lately about the way voices can be sent from one place to another by machines. Maybe f.a.gin isn't really with us at all; maybe that's just a machine that brings his voice to us. What do you think of that?"

"Interesting, and I suppose possible; but what difference does it make?"

"It's information; and f.a.gin himself always says that the more you know the better off you are. I suppose we don't really know this, but it's something worth keeping in mind until evidence comes in."

"Now that you've thought of it, maybe he'll tell iis if we ask him," Betsey pointed out. "He usually answers questions, except when he thinks it's for the good of our education to work out the answers ourselves; and how could we check on this one experimentally-except by taking the Teacher apart?"

"That's a point. Right now, though, the really important thing is to get this boat designed and built. Let's stick to that question for a while; we can sneak the other one hi when there's less chance of getting a lecture about letting our minds wander."

"All right." This conversation had brought them to the top of the hill where the robot was standing, among the belongings of the village. Here they reported in detail the results of their experiment. f.a.gin heard them through in silence.

"Good work," he said at the end. "You've learned something, if not everything. Your question about stability is a good one. I would suggest that you build a wooden frame-oh, about the size and structure of one wall of a hut, but lying on the ground. Then the sacks can be fastened to the corners; any time one corner gets lower 150.

CLOSE TO CRITICAL.

than the others, the buoyant force on it will increase, so the whole thing ought to be fairly stable."

"But wood sinks. How can you make a boat out of it?"

"Just count it as part of the weight the sacks-let's call those floats, by the way-have'to carry. You'll need even more floats, but don't let it worry you. I'd suggest that the two of you start the frame now; you might be able to finish it by yourselves, since there's plenty of wood. Then you can start fastening floats to it whenever you can get hold of any; you make a few kills defending "the herd every day, so you should make some progress.

"While you're doing that, you might lend your minds to another problem. The bathyscaphe is not staying at sea, but is drifting toward the sh.o.r.e."

"But that's no problem; it solves our problems. We'll just have to travel south along the sh.o.r.e until we find it.s You had already decided it must be south of us, you said."

"Quite true. The problem is the fact that Swift, with most of his tribe, seems to be standing on the sh.o.r.e waiting for it. Strictly speaking, Easy hasn't recognized Swift, partly because she can't tell one of you from another yet and partly because they aren't close enough, but it's hard to imagine who else it could be. This raises the question of whether Swift is accepting our offer, or proposes to keep the bathyscaphe and those in it for his own purposes. I suppose it's a little early to expect an answer from him; but if we don't get one some time today, I think we'll have to a.s.sume we're on our own and act accordingly."

"How?"

"That is the problem I suggest you attack right now. I suspect that whatever solution you reach, you'll find the boat will figure in it; so go ahead with it, as far as you can."

The Teacher fell silent, and his students fell to work. As f.a.gin had said, there was plenty of wood around, since the camp had not been there very long. Much of it, of course, was unsuitable for any sort of construction, Comprehension; Construction; Inundation 151 having the brittleness of so many Tenebran plants; but a few varieties had branches or stems both long and reasonably springy, and the two were able to locate in an hour what they hoped would be enough of these.

The actual cutting of them with their stone blades took rather longer, and binding them into a framework whose strength satisfied all concerned took longest of all. When completed, it was a rectangle of some fifteen by twenty feet, made of about three dozen rods of wood which an Earth-man would probably have described as saplings, lashed at right angles to each other to form a reasonably solid grillwork. Thinking of it as a floor, neither Nick nor Betsey was particularly happy; the s.p.a.ces were quite large enough to let their feet through, and the said feet were even less prehensile than those of a human being. They decided, however, that this was an inconvenience rather than a serious weakness, and shifted their attention to the problem of getting floats.

All this was reported to the Teacher, who approved. The approval was more casual than the two realized, for at the moment Raeker's attention was otherwise occupied. The bathyscaphe had now drifted within fifty yards of the sh.o.r.e and had there run aground, according to Easy. She had offered neither observation nor opinion as to the cause of the drift, and none of the scientists who had taken so many reels of data about the planet had been able to do any better. Easy herself did not seem bothered; she was now engaged in language practice across the narrow span of liquid that kept the bathyscaphe out of Swift's reach.

Raeker lacked even the minor comfort of being able to hear the conversation. The microphones of the outside speakers were, somewhat sensibly, located by the observation ports, so that the girl had taken up her station where she would have to shout to be heard in the Vindemiatrix. She did not bother to shout; most of the time she didn't even think of Raeker or, to be embarra.s.singly frank, of her father. She had not been inter- 152 CLOSE TO CRITICAL.

ested in the biology, geology, or the virtually nonexistent climatology of Tenebra; her interest in the rescue operation, while profound and personal, had reached the point where she could only wait for information which was always the same; but here were people, and people she could talk to-at least, after a fashion. Therefore, she talked, and only occasionally could anyone above get her attention long enough to learn anything.

She did find out that Swift was one of those present on the nearby sh.o.r.e, and Raeker duly relayed this information to Nick; but when questions were asked such as whether Swift planned to follow the suggestion he must by now have received via Nick's ex-prisoner, or how he had been able to find the bathyscaphe so quickly, no satisfactory answer was forthcoming. Raeker couldn't decide whether the trouble was Easy's incomplete mastery of the language, her lack of interest in the questions themselves, or a deliberate vagueness on Swift's part. The whole situation was irritating to a man who had exercised fairly adequate control over affairs on Tenebra for some years past; at the moment a majority of his agents were out of contact, what might be called the forces of rebellion were operating freely, and the only human being on the planet was neglecting work for gossip. Of course, his viewpoint may have been slightly narrow.

Things looked up toward the middle of the Tenebran afternoon. Jim and Jane returned, long before they had been expected, to increase the strength of the shipbuilding crew. They reported unusually easy travel and high speed, so they had reached their first search area on the initial day's travel, examined it, and been able to cover the other and return in something like half the expected time. They had found nothing in their own areas. They had seen a light to the south, but judged that John and Nancy would cover it, and had decided to stick to their own itinerary and get the desired report in. It was quite impossible, of course, for them to read any expression Comprehension; Construction; Inundation 153 from the robot, and Raeker managed to keep his feelings out of his voice, so they never suspected that their report was hi any way unsatisfactory. For a short tune, Raeker toyed with the thought of sending them out again to check the light; but then he reflected that in the first place John and Nancy would, as Jim said, have done so, and in the second place the 'scaphe had effectively been located, and he decided the pair were of more use getting leather. The lack of initiative they had displayed tended to support this conclusion. He spoke accordingly, and the two promptly took their spears up again and went hunting.

"One point may have struck you, Nick," Raeker said after they had gone.

"What is that, Teacher?"

"They saw the light to the south of their search area. That suggests strongly that the sh.o.r.e of this sea bends westward as it is followed south; and since the caves of Swift lie in the same direction, it is fairly likely that they are closer to the sh.o.r.e than we realized. This may account for Swift's finding the ship so quickly."

"It may," admitted Nick.

"You sound dubious. Where is the hole hi the reasoning?"

"It's just that I hunted with Swift's people for a good many days, and covered a lot of territory around his caves in the process, without either encountering the sea myself or hearing it mentioned by any of his people. It seems hard to believe that the lights of your missing ship could be seen a hundred miles, and something like that would be necessary to reconcile both sets of facts."

"Hmph. That's a point I should have considered. That light may call for more investigation, after all. Well, we'll know more when John and Nancy come hi."

"We should," agreed Nick. "Whether we actually will remains to be seen. I'm going to get back to fastening this float we've just glued onto the frame. I'm a lot surer that something constructive will come from that." He went 154 CLOSE TO CRITICAL.

off to do as he had said, and Raeker devoted himself to listening. Thinking seemed unprofitable at the moment.

With two more hunters, the raft progressed more rapidly than anyone had expected. The region of the new camp was not, of course, as badly hunted out as had been the neighborhood of the old village, and skins came in about as fast as they could be processed. Float after float was fastened in place, each corner being supplied in turn to keep the balance-Nick and Betsey were very careful about that. By the late afternoon so many had been attached that it was less a matter of keeping track of which corner came next than of finding a spot not already occupied-the frame was virtually paved with the things. No one attempted to calculate the result of its stability. If anyone thought of such a problem, he undoubtedly postponed it as something more easily determined empirically.

The work was not, of course, completely uninterrupted. People had to eat, there was the need to gather firewood for the night, and the herd to be guarded. This last, of course, frequently helped in the "shipyard" by providing leather without the need of hunting, but sometimes the fighting involved was less profitable. Several times the creatures attacking the herd were floaters, to everyone's surprise.

These creatures were reasonably intelligent, or at least learned rapidly as a rule to avoid dangerous situations.

They were also rather slow-flying things-resembling, as Easy had said, the medusae of her home world in their manner of motion-so that after a fairly short time in any one spot, when a reasonable number of them had been killed, the survivors learned to leave the herd alone. Nick and his friends had believed this end accomplished for the present camp; but in the late afternoon no less than four of the creatures had to be faced by the herders in not much over an hour. The situation was both unusual and quite painful: while a competent spearsman could count surely enough on grounding such a-creature, it was Comprehension; Construction; Inundation 155 nearly impossible to do so without suffering from its tentacles, whose length and poisonous nature went far to offset their owner's slow flight.

The attention of all four members of the group was naturally drawn to this peculiar state of affairs, and even the work on the raft was suspended while the problem was discussed. It was natural enough that an occasional floater should drift into the area from elsewhere, but four in an hour was stretching coincidence. The group's crests scanned the heavens in an effort to find an explanation, but the gentle air current toward the southwest was still too feeble at this distance from the volcano even to be felt, much less seen. The sky of Tenebra during the daytime is much too featureless to permit easy detection of something like a slow, general movement of the floaters; and the individual movement of the creatures didn't help. Consequently, the existence of the wind was not discovered until rainfall.

By this time, the raft seemed to be done, in that it was hard to see where any more floats could be attached. No one knew, of course, how many people it would support; it was planned to carry it to the ocean when the others returned, and determined this by experiment.

When the evening fires were lighted, however, it was quickly seen that the rain was not coming straight down. It was the same phenomenon that John and Nancy had observed the night before, complicated by the lack of an obvious cause. After some discussion, Nick decided to light three extra fires on the northeast side of the usual defenses, compensating for the extra fuel consumption by letting an equal number on the opposite side of the outer ring burn out. A little later he let go even more on the southwest, since no drops at all came from that direction even after the convection currents of the camp were well established. He reported the matter to f.a.gin.

"I know," replied the Teacher. "The same thing is happening where the ship is down, according to Easy.

The 156 CLOSE TO CRITICAL.

drops are slanting very noticeably inland. I wish she had some means of telling direction; we could find out whether the coast is actually sloping east where she is, or the rain actually moving in a slightly different direction. Either fact, if we know it, could be useful."

"I suppose she can't feel any wind?" asked Nick.

"Not inside the ship. Can you?"

"A little, now that the motion of the drops proves there must be some. I felt more around those fires I lighted when we getting away from the caves, but that's the only time. I think it's getting stronger, too."

"Let me know if you become more certain of that," replied Raeker. "We'll keep you informed of anything from the other end which may have a bearing on the phenomenon." Raeker's use of "we" was apt; the observation and communication rooms were filling with geologists, engineers, and other scientists. The news that Tenebra was putting on its first really mysterious act in a decade and a half had spread rapidly through the big ship, and hypotheses were flying thick and fast.

Easy was giving a fascinating, and fascinated, description of events around the bathyscaphe; for while she and her companion had by now seen plenty of the nightly rainfall, they were for the first time at a place where they could actually observe its effect on sea level. The sh.o.r.e was in sight, and the way the sea bulged up away from it as water joined the oleum was like nothing either child had ever seen. Looking downhill at the nearby sh.o.r.e was rather disconcerting; and it continued, for as the bathyscaphe rose with the rising sea level it was borne easily inland with the bulging surface. This continued until the density of the sea fell too low to float the ship; and even then an occasional b.u.mp intimated that its motion had not stopped entirely.

"I can't see anything more, Dad," Easy called at last. "We might as well stop reporting. I'm getting sleepy, anyway. You can wake us up if you need to."

Comprehension; Construction; Inundation 157 "All right, Easy." Rich made the answer for Raeker and the other listeners. "There's nothing much going on at Nick's camp right now except the wind, and that seems more surprising than critical." The girl appeared briefly on the screen, smiled good night at them, and vanished; Aminadorneldo's narrow face followed, and that station had signed off for the night.

Attention naturally shifted to the observation room, where the surface of Tenebra could actually be seen.

Nothing much was happening, however. The robot was standing as usual in the middle of the rather unbalanced fire circle, with the four natives s.p.a.ced around it-not evenly, tonight; three of them were rather close together on the northeast side and the fourth paced a beat that covered the remaining three- quarters of the circle. It was easy to see the reason with a few minutes' observation; for every fire snuffed out on the single man's beat, a full dozen went on the northeast. Someone was continually having to lope forward with a torch to relight one or two of the outer guard flames on that side. Occasionally even an inner fire would be caught, as a second drop blew too soon through the s.p.a.ce left unguarded by the effect of a first. There seemed no actual danger, however; none of the natives themselves had been overcome, and their manner betrayed no particular excitement.

While Raeker had been eating, his a.s.sistant had had one of the pupils pace off a course which he compared with the robot's length, and then by timing the pa.s.sage of a raindrop along it clocked the wind at nearly two miles an hour, which as far as anyone knew was a record; the information was spread among the scientists, but none of them could either explain the phenomenon or venture a prediction of its likely effects. It was an off-duty crewman, relaxing for a few minutes at the door of the observation chamber, who asked a question on the latter subject.

"How far from the sea is that camp?" he queried.

158 CLOSE TO CRITICAL.

"About two miles from the daytime coast line."

"How about the night one?"

"The sea reaches the valley just below that hill."

"Is that margin enough?"

"Certainly. The amount of rainfall doesn't vary from one year to the next. The ground moves, of course, but not without letting you know."

"Granting all that, what will this wind do to the sh.o.r.e line? With the sea not much denser than the air, the way it is late at night, I should think even this measly two-mile hurricane might make quite a difference."

Raeker looked startled for a moment; then he glanced around at the others in the room. Their faces showed that this thought had not occurred to any of them, but that most- the ones, he noted, most ent.i.tled to opinions-felt there was something to it. So did Raeker himself, and the more he thought of it the more worried he became. His expression was perfectly plain to Rich, who had lost none of his acuteness in the last month of worry.

"Think you'd better move them back while there's time, Doctor?" he asked.

"I'm not sure. It isn't possible to move the whole camp with just the four of them, and I hate to leave any of their stuff to be washed away. After all, they're fifty feet higher on that hill than the sea came before."

"Is fifty feet much, to that sea?"

"I don't know. I can't decide." The expression on Rich's face was hard to interpret; after all, he had spent his life in a profession where decisions were made whenever they had to be, with the consequences accepted as might be necessary.

"You'll have to do something, I should think," he said. "You'll lose everything if the sea gets them while they're there."

"Yes, but-"

"But nothing! Look there!" It was the same crewman who had raised the wind question who cut into the ex- Comprehension; Construction; Inundation 159 change. His eyes were fixed on the screen which looked seaward, and both Raeker and Rich knew what he had seen in the split second before they were looking for themselves. They were quite right.

Hours before they were normally due, the oily tongues of the sea were creeping into sight around the bases of the eastern hills. For perhaps a second no words were uttered; then Raeker proceeded to destroy the image the diplomat had been forming of him-that of a slow-thinking, rather impractical, indecisive "typical scientist." With the safety of project and pupils in obvious and immediate danger, he planned and spoke rapidly enough.

"Nick! All of you! Take one second to look east, then get to work. Make sure that all the written material, maps especially, is wrapped securely and fastened to the raft. Make them firm, but leave enough rope to fasten yourselves to it as well. You and the maps are top priority, and don't forget it.. With those as safe as possible, do the best you can at securing your weapons to yourselves or the raft. Hop to it!"

A question floated back from Nick; the transmission lag made it uncertain whether or not he had availed himself of the proffered observation time.