by Hal Clement
“I see. How long will it take to make enough gas to lift us?”
“I can’t tell; we don’t know the conductivity of the atmosphere. Once you start things going, there’s a bank of ammeters above the switches for each individual cell; if you’ll give me their reading after things start, I’ll try to calculate it for you.”
“All right. Where are the . . . oh, here; you labeled them decently. Upper right, a bank of twelve toggles, with a gang bar and a master?”
“That’s it. You can see the meters above them. Close the lot, hit the master, and give the readings.”
“All right.” The thin arm reached up and out of the field of vision, and everyone could hear the switches click. Easy pulled her hand back to her lap, settled back into the chair under her three hundred pounds of weight, eyed the dials one after another, and said, “The readings are all zero. What do I do now?”
TO BE CONTINUED
CLOSE TO CRITICAL
Second of Three Parts. The pressure down on Tenebra was enormous, and practically constant. But the political-psychological pressure in the research station was building up to exceed even Tenebra’s frightful pressure!
SYNOPSIS
The planet Tenebra, circling the star Altaic some sixteen light-years from the Solar system, has presented a major research problem. Its diameter and surface gravity are approximately three times those of Earth. Its temperature in the equatorial regions runs between three hundred seventy and three hundred eighty degrees Centigrade. Since its escape velocity permitted it to retain originally an amount of water per square mile about equal to that of Earth, the surface atmospheric pressure is about eight hundred times Earth normal. The atmosphere consists principally of water, laced with the biological by-products nitrogen, free oxygen, and, in this rather unusual case, oxides of sulfur.
It is an even more corrosive environment than that of Earth; in spite of the general acidity, the silicate surface rocks of the planet dissolve so rapidly that the crust is in a constant state of isostatic imbalance, and earthquakes are practically continuous.
After much engineering effort, a remote-controlled robot is designed and built capable of operating on Tenebra, and is successfully lowered to the surface. It explores for months, and finally achieves its intended purpose of locating a more or less intelligent indigenous race. The creatures appear to be in a stone-age culture, though only brief observations of them are made at first; when they are found to be egg-layers, the operators of the robot steal ten of their eggs, carry them to an isolated and uninhabited area, hatch them, and bring up the young creatures with the plan of educating them as go-betweens in the planned human-tenebran activities of the future.
The story actually opens as this project is about to get under way. The kidnaped natives have been educated for some sixteen years, and are presumed ready for work, though judging by their size they are not yet adult. They do not know their own background, but regard themselves as “Fagin’s people,” some humorist among the human operators having taught them to call the robot FAGIN. A vessel patterned after the ancient bathyscaphe is practically completed, ready to carry human explorers in person to Tenebra’s surface. Two political officers have come to the Vindemiatrix, the robot’s “mother ship,” to watch the start of the contact operation.
These officers are Councilor RICH, a human being, and Councilor AMINADABARLEE, a native of Dromm in the Eta Cassiopeia system. Both have brought members of their families, regarding the trip as little more than a routine affair, to be combined with a vacation if possible. The families are ELISE—“EASY” Rich, twelve-year-old daughter of the human officer, and AMINADORNELDO, son of the Drommian. The latter is physically as large as his father, but is actually about the equivalent of a human seven-year-old.
On the planet’s surface, one of the students has been sent out exploring, deliberately, in a direction likely to bring him into contact with his parent tribe. The student, NICK CHOPPER, does find the cave dwellers, learns their language after a fashion, and both shows and tells them some of the things he has learned from his teacher “back home”—the use of fire, the keeping of domestic animals, and such items. The leader of the cave tribe, SWIFT, has his cupidity aroused, and orders Nick to bring Fagin to the cave village. Nick agrees to do this provided the teacher agrees; Swift, a complete autocrat, takes violent exception to the condition mentioned and starts uttering threats. Nick becomes afraid for the safety of his fellows, and takes the unprecedented step of escaping from the cave village by night.
At night—Tenebra’s rotation period is nearly a hundred hours—enough heat is radiated from the upper layers of the atmosphere to allow it to shift into the liquid phase. This liquid water is enough denser than the still gaseous oxygen for separation to occur, and eventually huge raindrops reach the surface which contain only the truly dissolved oxygen. This is insufficient for active animals, and most Tenebran animal life collapses into more or less suspended animation when struck by one of the “clear” drops which fall after the first few hours of night. Nick is no exception to this rule; but he finds that by carrying torches he can see to avoid the drops and remain in breathable air. He starts his journey, failing to realize that Swift would cheerfully have let him escape even by daylight so that the cave dwellers could follow him back to Fagin’s village. Nick reaches home and reports to his teacher. The human beings realize the situation, but before they can form any plan of action Swift and his people attack. HELVEN RAEKER, the ecologist in charge of surface activities, watches helplessly while two of his pupils are killed and the village captured. Swift, in spite of the language problem, makes his wishes known to the robot operators; the machine has to go back to the cave village with him, or Swift will use fire on it. Since the destruction of the robot would wreck the entire project—even if another were built, it would take years to locate this particular area again on huge, unmapped, practically featureless Tenebra—the human beings have no choice.
Nick and the other survivors, contemptuously left behind, move their herd and personal belongings away from the village. They plan to rescue Fagin, and want a base of operations unknown to the cave dwellers. They find a site on a peninsula projecting into a sea to the east of the old village, and set up a camp; unfortunately, no one stops to think what may happen to the sea level at night.
On the Vindemiatrix the two children have been taken on a sightseeing tour by a crewman. This trip includes a visit to the practically completed bathyscaphe, orbiting just above Tenebra’s atmosphere. Failing to realize that Aminadorneldo is not an adult, the guide allows them to enter the ship unattended, and remains in the shuttle rocket which brought them from the Vindemiatrix. Raeker, Rich, and Aminadabarlee discover this during a radio conversation with the man; the Drommian becomes virtually hysterical as he points out the “stupid error”, and his anxiety is transmitted too well.
In his haste to get back to the children, the crewman makes the error of touching the bathyscaphe’s hull while still in contact with that of the tender; the potential difference is enough to set up a sneak circuit which fires a set of the bathyscaphe’s booster rockets—outboard attachments designed to get the ship into an entry orbit when the time came. The crewman is kicked onto one indeterminable vector and lost; the ship onto another.
Easy is able to report on the ‘scaphe’s radio, but before another shuttle can be readied and taken across the hundred and sixty thousand miles between Vindemiatrix and planet, her ship has entered atmosphere and is no longer interceptible. The elder Drommian can hardly find words to express his opinion of human stupidity; Raeker points out that the ship was made for just such a trip, is perfectly capable of getting down to atmospheric speed under automatic control, and once down has electrolysis apparatus able to get hydrogen from Tenebra’s atmosphere to fill its buoyancy cells and get back to where rockets will work and an interception be managed. The politicians do feel better for a while, after the ship succeeds in landing after a rough descent. Its automatic pilot, energ
ized by Easy on careful instructions from the Vindemiatrix’s engineers, has brought it down somewhere near the robot, though no one can tell just how near.
At first no one cares, since it is presumed that the ship can take off again unaided; but when the girl, under the engineers’ directions, closes the switches of the electrolyzers, they draw no current.
PART 2
V
NICK had chosen a fire on the landward side of the hill, so he was the first to have to consider the sea-level problem. In the home valley, of course, the water at night had never gotten more than thirty or forty feet deep; slow as the runoff was, enough always escaped at the valley foot to keep the village itself dry. He knew, from Fagin’s lectures, that the water which flowed away must eventually reach something like a sea or lake; but not even Fagin had stopped to think of what would happen then—naturally enough; the surface area of Earth’s oceans compared to the volume of an average day’s rainfall doesn’t correspond to much of a sea-level rise, to put it mildly.
On Tenebra, the situation is a trifle different. There is no single giant sea basin, only the very moderate-sized lake beds, which are even less permanent than those of Earth. What this difference could mean in terms of “sea” level might possibly have been calculated in advance, but not by any of Nick’s people.
At first, there was nothing to worry about. The great, cloudy drops drifted into sight from far above, settled downward, and faded out as the radiation from the fires warmed them a trifle. Then they came lower, and lower, until they were actually below the level of the hilltop on all sides.
Once a sharp quake struck and lasted for half a minute or more, but when Nick saw that the spit of land joining the hill to the shore was still there he put this from his mind. Something much more unusual was starting to happen. At home, raindrops which touched the ground after the latter had been cooled down for the night flattened into great, foggy half-globes and drifted around until a fire obliterated them; here they behaved differently. Drops striking the surface of the sea vanished instantly and by Nick’s standards, violently. The difference in pressure and temperature made the reaction between oleum and water much less noticeable than it would be in an Earthly laboratory, but it was still quite appreciable.
After each such encounter, it could be seen that further raindrops falling on the same area faded out a little higher than usual for a few minutes; Nick judged correctly that some heat was being released by the reaction.
He had been watching this phenomenon for some time, interrupted twice by the need to relight his fire when a particularly close drop smothered it, when he noticed that the hill was now an island. This startled him a trifle, and he turned all his attention to the matter. The quake hadn’t done it; he particularly recalled seeing the tombolo intact after the shaking was done. It didn’t take him too long to conclude that if the land wasn’t sinking, the sea must be rising; and a few minutes’ close watch of the shore line proved that something of that sort was happening. He called the others, to tell them of what he had seen, and after a few minutes they agreed that the same thing was happening on all sides of the hill.
“How far will it come, Nick?” Betsey’s voice was understandably anxious.
“I don’t see how it can get this high,” Nick answered. “After all, it hasn’t risen as much as the water in our own valley would have by this time of night, and this hill is nearly as high as the village. We’re safe enough.”
It got a little harder to stick to this belief as the hours passed and the sea grew higher. They could see the pools on shore swell and overflow into the main body; as time went on, more than one great river formed, carrying runoff from no one knew what drainage area. Some of the rivers were frightening, their centers as high or higher than the hill itself before they spread out and merged with the sea. By this time the violence of water-meeting-acid had subsided; the sea, at least near the shore, was pretty dilute.
Of course, “near the shore” might be too casual a statement. No one on the hilltop could tell for certain just where the shore was now. The route they had followed was deep under the acid sea, and the only evidence that dry land existed was the rivers which still came into view above sea level.
The island that had been a hill shrank steadily. The cattle seemed unperturbed, but were driven inside the ring of fires. Then this had to be drawn in—or rather, others built closer to the hilltop; and at last people and animals huddled together behind a single ring of glowing heat, while the sea bulged upward at their feeble protection. The raindrops were clear now; they had fallen from high enough levels to lose their suspended oxygen, and inevitably the last fires succumbed. Their heat had for many minutes past been maintaining a hollow in the surface of the sea; and as they cooled, the ocean reclaimed its own. Seconds after the last spark died every living being on the hilltop was unconscious, and a minute later only a turbulent dimple in the surface of the sea showed where the slightly warmer hilltop was covered. Nick’s iast thought was to the effect that at least they were safe from animals; they would be uncovered long before anything could get at them.
Apparently he wasn’t quite right. When they woke up the next morning and brushed the thin frost of quartz crystals from their scales, all the people were there, but the herd seemed to have diminished. A count confirmed this; ten cattle were gone, with only a few scales left behind. It was fortunate that the animals were of a species whose scale armor was quite frail, and which depended more on its breeding powers to survive; otherwise the meat-eaters who had come in the night might have made a different choice.
The realization that things lived in the sea came as a distinct shock to the entire party. They knew just about enough physical science to wonder where any such creature got its oxygen.
But the new situation called for new plans.
“There seems to be a catch in the idea of telling Fagin just to hunt along the seashore until he finds us,” Nick commented after breakfast. “The seashore doesn’t stay put too well. Also, we can’t afford to stay near it, if we’re going to lose eight or ten per cent of our animals every night.”
“What we’ll have to do is some more mapping,” commented Jim. “It would be nice to find a place protected by sea but which doesn’t get submerged every night.”
“You know,” remarked Nancy in a thoughtful tone, “one could find a rather useful employment for this place right here, if the proper people could be persuaded to visit it.” Everyone pondered this thought for a time, and the tone of the meeting gradually brightened. This did sound promising. Idea after idea was proposed, discussed, rejected or modified; and two hours later a definite —really definite—course of action had been planned.
None of it could be carried out, of course, until it was possible to get off the island, and this was not for a dozen hours after sunrise. Once the tombolo appeared, however, everyone went into furious activity.
The herd—what was left of it—was driven ashore and on inland by Betsey and Oliver. Nick, making sure he had his ax and fire-making equipment, started inland as well, but in a more southerly direction. The other five fanned out from the base of the peninsula and began mapping the countryside for all they were worth. They were to determine as much as possible, no later than the second night following, the area which was submerged by the sea at its highest. The group was then to pick a more suitable camp site to the north of the previous night’s unfortunate choice. They were to settle at this point, and send a pair of people each morning to the base of the peninsula until either Nick returned or ten days had passed; in the latter event, they were to think of something else.
Nick himself had the task of contacting Fagin. He alone of the group was just a trifle unclear on how he was to accomplish his job. Tentatively, he planned to approach the cave village at night, and play by ear thereafter. If Swift’s people had gotten into the habit of moving around at night with torches, things would be difficult. If not, it might be easy—except that his own approach would then be very noticeable.
Well, he’d have to see.
The journey was normal, with enough fights to keep him in food, and he approached the cliff on the evening of the second day. He had circled far around to the west in order to come on the place from the cliff top; but even so he halted at a safe distance until almost dark. There was no telling where hunting parties might be encountered, since there was a path up the cliffs in nearly constant use by them.
As darkness fell, however, Nick felt safe in assuming that all such groups would be back at their caves; and checking his fire-lighting equipment once more, he cautiously approached the cliff top. He listened at the edge for some time before venturing to push his crest over, but no informative sounds filtered up and he finally took the chance. The cliff was some three hundred fifty feet high at that point, as he well knew; and he realized that even a single spine would be quite visible from below by daylight. It might be somewhat safer now, since no fires appeared to have been lighted yet.
When he finally did look, there was nothing to see. There were no fires, and it was much too dark for him to see anything without them.
He drew back again to think. He was sure the village and its inhabitants lay below, and was morally certain that Fagin was with them. Why they had no fires going was hard to understand, but facts were facts. Perhaps it would be safe to try to sneak up to the village in the dark—but the rain would come soon, and that would be that.
