Heavy Planet

by Hal Clement

  “There isn’t enough time for the job. The ice is still growing toward us. We might have to get the treads a whole body-length deeper before they’ll run free. Leave the trucks alone, Tak. We’ll have to try something else.”

  “All I want to know is what.” Beetchermarlf showed him. Taking a light with him this time, he climbed once more to the top of the truck. Takoorch followed, mystified. The younger sailor reared up against the shaft which formed the swiveling support of the truck, and attacked the mattress with his knife. “But you can’t hurt the ship!” Takoorch objected. “We can fix it later. I don’t like it any better than you do, and I’d gladly let the air out by the regular bleeder valve if we could only reach it; but we can’t, and if we don’t get the load off this truck very soon we won’t do it at all.” He continued slashing as he spoke. It was little easier than moving the stones. The mattress fabric was extremely thick and tough; to support the Kwembly it had to hold in a pressure more than a hundred pounds per square inch above the ground. One of the nuisances of the long trips was the need to pump the cells up manually or to bleed off excess pressure, when the height of the ground they were traversing changed more than a few feet. At the moment the mattress was a little flat, since no pumping had been done after the run down the river, but the inner pressure was that much higher. Again and again Beetchermarlf sliced at the same point on the tautstretched surface. Each time the blade went just a little deeper. Takoorch, convinced at last of the necessity, joined him. The second blade’s path crossed that of the first, the two flashing alternately in a rhythm almost too fast for a human eye to follow. A human witness, had one been possible, would have expected them to sever each other’s nippers at any moment. Even so, it took many minutes to get through. The first warning of success was a fine stream of bubbles which spread in all directions up the slope of the bulging gas cell. A few more slashes and the cross-shaped hole with its inch-long arms was gushing Dhrawnian air in a flood of bubbles that made the work invisible. The prisoners ceased their efforts. Slowly but visibly the stretched fabric was collapsing. The bubbles fled more slowly across its surface, gathering at the high point near the wall of ice. For a few moments Beetchermarlf thought the fabric would go entirely flat, but the weight of the suspended truck prevented that. The center of the cell or the point at which the truck was attached (neither of them knew just where the cell boundaries were) was straining downward: it was now pull instead of push. “I’ll start the engine again and see what happens,” said Beetchermarlf. “Get forward again for a minute.” Takoorch obeyed. The younger helmsman deliberately wedged a number of pebbles under the front ends of the treads, climbed the truck once more and settled down. He had kept the light with him this time, not to help him with handling controls but to make it easier to tell how and whether the unit moved. He looked at the point of attachment a few inches above him as he started the engine once more. The pebbles had provided some traction; the fabric wrinkled and the swivel tilted slightly as the truck strained forward. An upper socket, inaccessible inside the cell, into which the shaft telescoped, prevented the tilt from exceeding a few degrees. The trucks, of course, could not be allowed to touch each other but the strain could be seen. As the motion reached its limit the trucks continued moving, but this time they did not race free. Sound and tactile vibrations both indicated that they were slipping on the pebbles and after a few seconds the feel of swirling, eddying water became perceptible against Beetchermarlfs s air suit. He started to climb down from the truck and was nearly swept under one of the treads as he shifted grips. He barely stopped the motor in time with a hasty snatch at the control. He needed several seconds to regain his composure after that; even his resilient physique could hardly have survived being worked through the space between treads and rocks. At the very least, his air suit would have been ruined. Then he took time to trace very carefully the control cords leading from the reactor to the upper guides along the bottom of the mattress, following them by eye to the point above the next truck forward where he could reach them. A few seconds later he was on top of the other truck, starting the motor up again from a safe distance and mentally kicking himself for not having done it that way from the beginning. Takoorch reappeared beside him and remarked, “Well, we’ll soon know whether stirring water up does any warming.”

  “It will,” replied Beetchermarlf. “Besides, the treads are rubbing against the stones on the bottom instead of kicking them out of the way this time. Whether or not you believe that stirring makes heat, you certainly know that friction does. Watch the ice, or tell me if the neighborhood is getting too hot. I’m at the lowest power setting, but that’s still a lot of energy.” Takoorch rather pessimistically went over to a point where the cairn should be visible if it were ever freed of ice. He settled down to wait. The currents weren’t too bad here, though he could feel them tugging at his not-too-well-ballasted body. He anchored himself to a couple of medium-sized rocks and stopped worrying about being washed under the treads. He did not really see how merely stirring water could heat anything but Beetchermarlf. point about friction was comforting. Also, while he would not have admitted it in so many words, he tended to give more weight to the younger sailor’s opinion than to his own and he fully expected to see the ice yielding very shortly. He was not disappointed; within five minutes he thought that more of the stony bottom was becoming visible between him and the barrier. In ten he was sure, and a hoot of glee apprised Beetchermarlf of the fact. The latter took the risk of leaving the control lines untended to come to see for himself and agreed. The ice was retreating. Immediately he began to plan. “All right, Tak. Let’s get the other units going as fast as they melt free and we can get at their controls. We should be able to melt the Kuvmbly loose from this thing, besides getting ourselves out from under.” Takoorch asked a question. “Are you going to puncture the cells under all the powered units? That will let the air out of a third of the mattress.” Beetchermarlf was taken slightly aback. “I’d forgotten that. No, well, we could patch them all, but-no, that’s not so good. Let’s see. When we get another power unit clear we can mount it on the other truck that’s on this cell we’ve drained already; that will give us twice as much heat. After that I don’t know. We could see about digging under the others-no, that didn’t work so well-I don’t know. Well, we can set one more driver going, anyway. Maybe that will be enough.”

  “We can hope,” said Takoorch dubiously. The youngster’s uncertainty had rather disappointed him, and he wasn’t too impressed with the toned-down substitute for a plan; but he had nothing better himself to offer. “What do I do first?” he asked. “I’d better go back and stand by those ropes, though I suppose everything’s safe enough,” replied Beetchermarlf indirectly. “Why don’t you keep checking around the edges of the ice, and get hold of another converter as soon as one is unfrozen? We can put it into that truck,” he indicated the other one attached to the deflated cell, “and start it up as soon as possible. All right?” Takoorch gestured agreement and started surveying the ice barrier. Beetchermarlf returned to the control lines, waiting passively. Takoorch made several circuits of the boundary, watching happily as the ice retreated in all directions. He was a little bothered by the discovery that the process was slowing down as the cleared space increased but even he was not too surprised. He made up his mind eventually which of the frozen-in power boxes would be the first to be released and settled down near it to wait. His attitude, like that of his companion waiting at the controls, cannot be described exactly to a human being. He was neither patient nor impatient in the human sense. He knew that waiting was unavoidable, and he was quite unaffected emotionally by the inconvenience. He was reasonably intelligent and even imaginative by both human and Mesklinite standards, but he felt no need of anything even remotely resembling daydreaming to occupy his mind during the delay. A half-conscious mental clock caused him to check the progress of the melting at reasonably frequent intervals; this is all a human being can grasp, much less describe, about w
hat went on in his mind. He was certainly neither asleep nor preoccupied, because he reacted promptly to a sudden loud thud and a scattering of pebbles around him. The spot where he was lying was almost directly aft of the truck which was running, so he knew instantly what must have happened. So did Beetchermarlf, and the power unit was shut down by a tug on the control line before a man would have perceived any trouble. The two Mesklinites met a second or two later beside the truck which had been running. It was in a predictable condition, Beetchermarlf had to admit to himself. Mesklinite organics are very, very tough materials and the tread would have lasted for many more months under ordinary travel wear: deliberate friction against unyielding rocks, even with very modest engine power, was a little too much for it. Perhaps the word “unyielding” does not quite describe the rocks; those which had been under the moving band of fabric had been visibly flattened on top by the wear of the last hour or so. Some of them were more than half gone. The young helmsman decided, after careful examination, that the failure of the tread had been due less to simple wear than to a cut started by a formerly spherical pebble which had worn down to a thin slice with sharp edges. Takoorch agreed, when the evidence was pointed out to him. There was no question about what to do, and they did it at once. In less than five minutes the power converter had been removed from the damaged truck and installed in the one aft of it, which had also been unloaded by puncturing the pressure cell. Without worrying about the certainty of destroying another set of treads, Beetchermarlf started this one up promptly. Takoorch was uneasy now. The reasonable optimism of an hour before had had the foundation cut from under it; he was doubtful that the second set of treads would last long enough to melt a path all the way to freedom. It occurred to him, after some minutes of wrestling with the question, that concentrating the warmed water on one spot might be a good idea and he suggested this to his companion. Beetchermarlf was annoyed with himself for not having thought of the same thing earlier. For half an hour the two labored, heaping pebbles between and around the trucks surrounding their heat source. They eventually produced a fairly solid wall confining some of the water they were heating to a region between the truck and the nearest part of the ice wall. Takoorch had the satisfaction of seeing the ice along a two-yard front toward the starboard side of the Kwembly melting back almost visibly. He was not completely happy, of course. It did not seem possible to him, any more than it did to Beetchermarlf, that the treads could last very long on the second truck either; and if they went before the way out was clear, it was hard to see what else they could do toward their own salvation. A man in such a situation can sometimes sit back and hope that his friends will rescue him in time; he can, in fact, carry that hope to the last moment of consciousness. Few Mesklinites are so constituted, and neither of the helmsmen was among the number. There was a Stennish word which Easy had translated as “hope” but this was one of her less successful inferences from context. Takoorch, driven by this indefinable attitude, stationed himself between the humming truck and the melting ice, hugging the bottom to keep from deflecting the warmed current of water, trying to watch both simultaneously. Beetchermarlf remained at the control lines. Since no digging had been done under the second truck, the friction was greater and the heating effect stronger. The control was for speed rather than power, in spite of the words the helmsman had used. Naturally but unfortunately, the wear on the treads was also greater. The heavy thud which announced their failure came annoyingly soon after the completion of the rubble wall. As before, the two bands of fabric gave way almost simultaneously: the jerk imparted to the drive shaft as one let go was enough to take care of the other. Again the Mesklinites acted instantly, in concert, and without consultation. Beetchermarlf cut the power as he plunged away from his station toward the melting surface; Takoorch got there before him only because he started from halfway there. Both had blades out when they reached the barrier, and both began scraping frantically at the frosty surface. They knew they were fairly close to the Kuembly’s side; less than a body length of ice remained to be penetrated, at least horizontally. Perhaps before freezing took over once more sheer muscle could get them through … Takoorch’s knife broke in the first minute. Several of the human beings above would have been interested in the sounds he made, though not even Easy Hoffman would have understood them. Beetchermarlf cut them off with a suggestion. “Get behind me and move around as much as you can, so that the water cooled by the ice is moved away and mixed with the rest. I’ll keep scraping, you keep stirring.” The older sailor obeyed, and several more minutes passed with no sound except that of the knife. Progress continued, but both could see that its rate was decreasing. The heat in the water around them was giving out. Though neither knew it, the only reason that their environment had stayed liquid for so long was that the freezing around them had cut of the escape of the ammonia. The theoreticians, both human and Mesklinite, had been perfectly correct, though they had been no help to Dondragmer. The freezing under the Kwembly had been more a matter of ammonia slowly diffusing into the ice through the still-liquid boundaries between the solid crystals. The captain, even with this information, could have done no more about it than his two men now trapped under his ship. Of course, if the information had come as a prediction instead of an inspired afterthought, he might have driven the Kwembly onto dry land, if she had been able to move in time. Even if Beetchermarlf had had all this information at the time, he would not have been considering it consciously. He was far too busy. His knife flashed in the lamp light as rapidly and as hard as he dared. His conscious mind was concerned solely with getting the most out of the tool with the least risk of breaking it. But break it he did. He never cared to discuss the reason later. He knew that his progress was slowing, with the urge to scrape harder changing in inverse proportion; but being the person he was, he disliked the faintest suggestion that he might have been the victim of panic. Being what he was also prevented him, ever, from making any suggestion that the bone of the knife might have been defective. He himself could think of no explanations but those two. Whatever the reason, the knife gripped in his right-forward pair of chelae was suddenly without a blade, and the sliver of material lying in front of him was no more practical to handle for his nippers than it would have been for human fingers. He flung the handle down in annoyance and since he was under water didn?t even have the satisfaction of hearing it strike the bottom violently. Takoorch grasped the situation immediately. His comment would have been considered cynical if it had been heard six million miles above, but Beetchermarlf took it at face value. “Do you think it would be better to stay here and freeze up near the side or get back toward the middle? The time won’t make much difference, I’d say.”

  “I don’t know. Near the side they might find us sooner; it would depend on where they come through first, if they manage to do it at all. If they don’t, I can’t see that it will make any difference at all. I wish I knew what being frozen into a block of ice would do to a person.”

  “Well, someone will know before long,” said Takoorch. “Maybe. Remember the Erket.”

  “What has that to do with it? This is a genuine emergency.”

  “Just that there are a lot of people who don’t know what happened there.”

  “Oh, I see. Well, personally I’m going back to the middle and think while I can.” Beetchermarlf was surprised. “What’s there to think about? We’re here to stay unless someone gets us out or the weather warms and we thaw out naturally. Settle down.”