Cycle of Fire

VII. ENGINEERING

THEY NEEDN’T have worried. It was decidedly an anticlimax, but after more than an hour of searching the crater floor they were forced to conclude that there was no animal in the enclosure larger than a squirrel. This was a relief in one way, but left the reason for the trap in the tunnel even more obscure than it had been. They discussed this as they rested beside the pond and ate meat which Dar’s bow had provided.

“Finding nothing living here is reasonable, I suppose, with the city deserted, but you’d think that there’d at least be a skeleton,” Kruger remarked.

Dar scraped at the loamy soil with one claw.

“I don’t know about that. Even bones from which flesh has been entirely eaten don’t last very long, and if there’s much meat left they go immediately. Still, you’d expect some traces of occupancy in those dens along the wall — the ones we saw from overhead.” These openings had all been explored in search of either the inhabitant of the pit or another way out of it, but were nothing but concrete caves.

Kruger’s tendency was to sit and theorize about the possible function of the crater in the days when the city was inhabited; Dar had a rather more practical question.

“Whether it was to keep bad people or bad animals means little to us just now,” he said. “The trouble is it seems adequate to keep us, too. Admittedly, we will not starve; there is food and water. However, I have too few years to live to want to spend them in this place, and I am far from my books. Would it not be better to be planning a way out?”

“I suppose it would,” Kruger admitted. “Still, if we knew what was kept here we might have a better idea of how to do just that — if it was a lion cage and we knew it, we at least would know that the restraints were designed for lions. As it is…”

“As it is we know all about the restraints, as you call them. If we start up that tunnel it gets hot. I have no first-hand knowledge of what will happen if I walk into that steam, but I’m willing to assume that my Teachers had their reasons for keeping me away from such things. I notice that you, who are not afraid of fire, have shown no eagerness to get in front of those steam pipes either.”

“True enough. I’m not afraid of fire that I control, but that doesn’t apply here. But wait a minute — you said something just then. If we go up the tunnel we hit that trigger section of the floor, but that’s not right in front of the jets. It can’t extend very close to them, either, or we’d have been blistered on the way in. It should be possible to go up the corridor, get past the part of the floor that controls the valves, and wait there until the steam cuts off again, and then just walk out.”

Dar was a little doubtful. “It seems too simple,” he said. “What could they have been trying to hold here that would simply be scared of the noise? That’s all that was really keeping it in, if your idea is right.”

“Maybe that’s just what it was,” retorted Kruger. “Let’s try it, anyway.”

Neither of them was surprised this time when the roar of steam answered their weight on the significant floor section. Kruger led the way as close as he dared to the blast of hot gas, which emerged from nozzles at one side of the corridor and vanished — for the most part — into larger openings in the other. Bits of the streaming vapor eddied out of the line and curled about the two in swirling wisps of hot fog, but there was enough air to breathe, and for minute after minute they waited at the very edge of the jet of death.

At long last Kruger was forced to admit that Dar had been right. They were much closer to the steam than they had been when it first started on their way in, but it seemed that it was not going to stop now. Apparently the machinery was more complicated than Kruger had believed.

There was, of course, another possible interpretation. Kruger did not want to consider it. Whether or not it had occurred to Dar he did not know and carefully refrained from asking when they were back at the side of the pool.

“Do you suppose that the trap was for these little things we’ve been eating?” asked Dar after a long silence.

“Coming around to my logic?” queried Kruger. “I don’t know, and don’t see what good it will do us if it was.”

“Neither did I until you spoke as you did a little while ago. However, I started to wonder just how much weight it took to set off that valve. We know that our combined weights will; I think that yours alone would, but we don’t know whether mine would and if it did, how little could be placed on that part of the floor without starting the works.”

“If yours touches it off what good would any further knowledge be?”

“It is not necessary to place all one’s weight on one block, is it? It might be possible to place branches or logs on the floor so that we would…” Kruger was on his feet again; there was no need to finish the sentence. This time Dar led the way back up the tunnel, Kruger remaining several paces behind.

In due time the roar of steam showed that the trigger had been activated. Kruger stayed where he was, while Dar moved back toward him. The roar ceased; it was definitely Dar who had operated the valve. It was difficult to be sure of the precise position of the trigger block in the nearly dark passage. Dar moved back and forth until he had located the edge of the sensitive area to the last inch; then he spoke to his companion.

“Nils, if you will go back to the open space and find some rocks of various weights we’ll learn just how sensitive this thing is. I’ll stay here and mark the place.”

“Right.” Kruger saw what the little fellow had in mind and obeyed without comment or question. He was back in five minutes with an armload of lava boulders whose total weight approximated Dar’s fifty-five pounds, and the two proceeded to roll them one by one across the fatal line. Some minutes of alternate roaring and silence yielded evidence that the trigger was indeed operated by weight and that approximately fifteen pounds was required to open the valves. Further, the fifteen pounds could be applied at any point in the width of the corridor for a distance of at least ten feet. Merely spreading their weights would do no good, it seemed; as soon as the total reached the fifteen-pound limit the steam came on.

“We can still make a bridge right across the thing,” pointed out Dar when this conclusion was reached.

“It’s going to be a job,” was Kruger’s rather pessimistic reply. “Two knives will mean quite a lot of whittling.”

“If you can think of something else I will be glad to try it. If not I suggest we start work.” As was so often the case Dar’s words seemed too sensible to oppose and they returned to the sunlight to seek materials.

Unfortunately, Kruger had been right too. They had the two knives, neither one particularly heavy. The trees of Abyormen differ among themselves as widely as those of any other planet, but none of them is soft enough to be felled with a sheath-knife in half an hour — or half a day. The travelers hoped to find something thick enough to carry them without bending noticeably and thin enough to cut and transport. The patch of forest in the crater was not very extensive, and they might have to be satisfied with much less than they wanted; neither could remember noticing a really ideal trunk during their earlier search, though of course they had had other matters in mind at the time.

Kruger was still dubious as they wandered about the crater floor. He was no lazier than the average, but the thought of attacking even a six-inch trunk with his knife did not appeal to him. That situation has probably been responsible for most of the discoveries and inventions of the last half million years, so it is not too surprising that his mind was busy with other things as they hunted.

Nor is it surprising that some facts which had been available in the filing-case of his mind for some time should suddenly fall together; that seems to be the way ideas are usually born.

“Say, Dar,” he said suddenly, “how come if this city is deserted, and the power plants presumably shut down, there is still all this steam? I can understand a simple lever-and-valve arrangement’s lasting this long, but what about the energy supply?”

“There is much steam around,” pointed out Dar. “Might they not have gone far underground, to tap the same fire that fed these volcanoes or the hot water at the village?” Kruger’s face fell a little, as he realized he should have thought of this himself.

“Just the same,” he said, “it seems to me that there can be only so much steam there. Why shouldn’t we leave some rocks on that trigger and just wait for the thing to run out?”

“It’s been running, on and off, for quite a while now,” said Dar doubtfully, “and hasn’t shown any signs of running down. Still, I suppose there’s a chance. Anyway, once the weight is in place it won’t use any of our time; we can go back to this job. Let’s do it.”

“It won’t take both of us. I’ll be right back.” Kruger returned to the tunnel, rolled one of the rocks they had left on the floor toward the trap until his ears told him it had gone far enough, and was back with Dar in less than two minutes.

By the perversity of fortune the only tree that seemed usable for their purpose was located about as far from the tunnel as it could be. Complaining about it would do no good, however, and the two set to work with their tiny blades. Its wood was softer than pine, but even so the seven-inch trunk took some time to cut through in the circumstances. They rested several times, and stopped to hunt and eat once, before the big plant came down.

This particular tree arranged its branches in more or less the fashion of a multi-layered umbrella, with four or five feet between layers. The plan was to save some of the branches from the layer nearest the base and from that nearest the top, so that they could serve as “legs” to keep the weight of the main trunk and its burdens off the ground. Kruger would not have been too surprised had the job taken a year, but determination and increasing skill paid their dividends and only a few terrestrial days passed before the work was ready to be dragged to the tunnel. Throughout that time the howl of the steam never subsided; there was no need to visit the tunnel to check the jets’ behavior. If there was any diminution in the sound it was too gradual for either of them to detect while they worked; the phenomenon that did attract their attention was its sudden stopping.

This happened just as they were starting to drag the log toward the tunnel. For a moment the echoes of the whistling roar played back and forth across the pit; then silence took their place. Dar and Kruger looked at each other for a moment, then, without pausing for discussion, started running toward the opening.

Dar reached it first in spite of his shorter legs; the undergrowth barring the way was sufficiently open to let him through fairly easily while Kruger had to force his way. The floor of the tunnel was wet with a trickle of near-boiling water, evidently from steam which had condensed on the walls and roof during the past few dozen hours. The air in the passage was only saved from being unbreathable by the draft entering it from the pit; only a few yards of the corridor could be seen in the swirling fog. Step by step they advanced as the current drove the mist curtain before it, and presently they reached the stones that had been left near the trigger block. Dar would have continued, but Kruger restrained him with a word of caution.

“Let’s hold it a moment and see whether the rock I put on the trigger is still there. Maybe it got washed off by the stream; it wasn’t very heavy.” Dar privately felt that a fifteen-pound boulder would need something more powerful than the trickle in the tunnel to shift it, but stopped anyway. Only a few moments were needed to see that the rock was still in place; presumably the trigger was still depressed, and therefore the steam had been shut off by some other cause. A little uneasily, Kruger shifted his own weight forward until he was beside the rock. Nothing happened, and for several seconds the two looked thoughtfully at each other. The same possibilities were passing through their minds.

Neither knew the details of the valve system that controlled the steam. There might be any number of safety devices for shutting it off before complete exhaustion of the supply — devices which could be overridden by other triggers if a determined effort was made to escape through the corridor. The trouble was that the makers were not human and, as far as could be told, not members of Dar’s race either; there was simply no way of guessing what they might have considered logical design.

“I guess there’s only one way to find out, Dar. You’d better let me go first; I could probably stand a brief dose if the thing started up, but from what your Teachers have said there’s no telling what it would do to you.”

“That’s true, but my weight is less. Perhaps it would be better if I were to start.”

“What good will that do? If it doesn’t trip for you we still won’t know that it won’t for me. You just be set to come on the double if I make it.” Dar offered no further argument but helped his big companion make sure that the small amount of equipment he carried was securely fastened — neither one wanted to come back for anything that was dropped. With this accomplished Kruger wasted no more time; he set off up the tunnel as fast as his strength would allow.

Dar watched until he was sure that the boy was well past the steam jets; then he followed. He caught up with Kruger at the mouth of the tunnel, but the two did not stop until they were outside the building from which the passage led. No sound had come from behind them, and gradually Kruger’s panting slowed as he waited and listened.

“I guess that did it,” he said at last. “Now what do we do? We’re something like half a year late for our talk with that Teacher back at the village; do you think we can persuade him that our lateness was accidental, and that he’ll be in a mood to give back your books?”

Dar thought for some time. Even he had become a little tired of being put off each time he asked for his property, and Kruger’s implied point was a good one. Dar was fair-minded enough to admit to himself that their lateness was not entirely accidental; they should have started back to the village well before the time they became trapped in the crater.

“I wonder why the villagers did not come after us?” he asked suddenly. “They knew about where we were and they certainly were able to find us the other time.”

“That’s a good question and I can’t see any answer offhand. The steam shouldn’t have scared them away; they were used to those geysers.”

“Do you suppose they could have known we were trapped and been satisfied to leave us where we were? A searching party could have heard the steam from a long distance and checked up on us by simply looking over the crater edge.”

“That’s a distinct possibility — except that the trap was so easy to get out of that they would hardly suppose we could be permanently held by it. In that case there would still be guards around, and they’d probably have met us on the way out.”

“Perhaps there was only a single guard, who didn’t think the noise would lead to anything — they might think of the jet as inexhaustible; I’m sure I would have. In that case he might only have just started for reinforcements. I’m armed, and he might not feel it his duty to attempt Our capture single-handed.”

“A possibility which we have no means of checking — except by waiting here to see whether the soldiers turn out. Should we do that?”

“I — guess not.” Dar was still a little reluctant in his answer. “You were probably right all along. We have been wasting time and I have only sixteen years. We had better start for the Ice Ramparts once more and hope we can get there in time to return here with enough aid to get the books.”

“That suits me — it always has. This steam bath gets no more comfortable with time; in fact, I’d swear it got a little hotter each year. Let’s go — and fast.” They suited action to the word and left mountain and city behind them without further discussion.

Travel was a little easier along the seacoast. The beach was usually of hard-packed sand, though it was almost always narrow — Abyormen had no moon massive enough to raise noticeable tides, and this close to the pole even those caused by Theer were not enough to measure. Kruger had been a little doubtful about their traveling on a surface that took their tracks so clearly, but Dar pointed out that they had told enough since their capture to give any would-be pursuers the proper direction. Speed, and speed alone, was all that would serve the fugitives at this point.

There were numerous animals in the forest, which came unbroken to the beach, and none of them seemed to have any particular fear of the travelers. Time and again Dar’s crossbow knocked over their dinner, which was dissected on the spot and eaten either as they traveled or during the occasional stops which were needed for sleep.

Once or twice the tips of volcanic cones could be seen well inland, but only once did one of them hamper their travel in any way. Then they had to spend some hours working their way across a small field of lava which had flowed into the sea at some time in the past.

Usually they could see the coast for miles behind them, and oftener than not one of Dar’s eyes was turned in that direction, but the only moving things he ever saw were wild animals, usually quite unconcerned with the travelers.

The trip became a monotony of walking in steaming heat or unpleasantly warm rain. Occasionally Kruger interrupted the traveling with a bath in the sea; warm though the water was, the refreshment resulting from the swim made him feel the risk was worth while. He did this only when Dar wanted to rest, since the Abyormenite had no use for swimming and seemed to think of little except the amount of time they were spending en route.

They had no precise means of measuring the distance they traveled, so that not even Dar could guess when the islands they were seeking would appear; but appear they eventually did. Dar gave a grunt of relief when the first of the little humps appeared far out on the horizon.

“Fifteen years to go. We’ll make it yet.” His confidence may have been a trifle misplaced, but Kruger’s ignorance of the scale of the maps he had seen kept him from realizing that the island chain by which Dar meant to proceed led across eight hundred miles of ocean, and that almost as much land lay between its end and the point on the ice cap which was their goal. He assumed the native’s judgment to be sound and almost relaxed.

“How do we get across the sea?” he contented himself with asking.

“We float.” And Dar Lang Ahn meant it.

This worried Kruger, and his worry did not grow less as time went on. It became increasingly evident that Dar intended to make his trip on a raft, which was the only sort of craft their tools would allow them to build; and even his ignorance of the distance to be covered did not make the boy any happier at the prospect. There was no provision being made for sails; when Kruger mentioned this and finally managed to explain what sails were the pilot explained that the wind always blew against them anyway. They would have to paddle.

“Does the wind never change?” Kruger asked in dismay as he considered the task of moving by muscle power the unwieldy thing that was beginning to take shape on the beach.

“Not enough to matter.”

“But how do you know?”

“I have been flying this route all my life, and a glider cannot be flown by one who does not know what the currents are doing.”

“Didn’t you say that this island chain marked the air route your gliders always take to the Ice Ramparts?” Kruger asked suddenly.

“Those coming from Kwarr, yes.”

“Then why haven’t we seen any?”

“You have not been looking up. I have seen three since we reached this spot. If your eyes were only on the sides of your head and stuck out a little more…”

“Never mind my optical deficiencies! Why didn’t you signal them?”

“How?”

“You were going to reflect sunlight from your belt buckles when I found you; or we could light a fire.”

“Your fire-lighter is in the keeping of our friends whom we have left behind, and even if we lighted one you should know by now that one of my people would not approach a fire. If the pilot saw the smoke he would avoid it and more than likely report it as a new center of volcanic activity.”

“But how about the reflection? Your buckles are still shiny!”

“How does one aim a beam of light from a mirror? I was using the method when you found me because it was the only possible one; I would have been as dead, had you not appeared, as I shall be less than fifteen years from now.”

“Can’t you see the beam of light that the buckle reflects?”

“No. I once saw a mirror so perfectly flat that one could see the ray of sunlight coming from it if there were a little haze in the air, but my buckles are not in that class.”

“Then if they spread the beam it should be that much easier to hit something with it. Why do you not try, at least?”

“I think it would be a waste of time, but if you can suggest a way of pointing the beam reasonably closely you may try the next time a glider comes in sight.”

“Let me see the buckles, please.”

Dar complied with the air of one amusing a rather dull child. Kruger examined the plates of metal carefully. They were more nearly flat than Dar’s words had led him to hope, rectangular in shape, about two inches wide and four long. Two holes about an inch square were present in each one, and between these a single small circular hole which in service held a peg for securing the leather straps threaded through the larger openings. Kruger smiled as he finished his examination, but handed them back to their owner without any comment except, “I’ll take you up on that offer. Let me know when another glider appears, if I don’t see it myself.”

Dar went back to work with little interest in Kruger’s idea, whatever it might be, but he obediently kept one eye roving about the horizon. He was a little annoyed that Kruger was now constantly lifting his head to do the same thing, but was fair-minded enough to admit that the poor creature couldn’t help it. He was even more annoyed when Kruger proved the first to spot an approaching aircraft, but watched with interest as the boy prepared to use the buckles in signaling.

All he saw, however, was that a buckle was held before one of the small eyes, which apparently sighted through the center hole at the approaching glider. Dar could see no reason why this should give any assistance in aiming the reflected beam. He did see the spot of light shining through the same central opening on Kruger’s face, but had no means of telling that the boy had so placed the mirror that the reflection of his own features in its back had taken a definite position — one which brought the spot of sunlight on the reflected face directly on the hole through which he was looking at the glider. Holding himself as motionless as possible, he spoke.

“Do you have any special signal that depends on flashes of light — something the pilot would definitely recognize?”

“No.”

“Then we’ll just have to hope that he’ll be curious about a constant blink.” Kruger began rocking the mirror back and forth as he spoke.

Dar Lang Ahn was astonished when the actions of the aircraft showed plainly that its occupant had seen the flashes and he made no secret of the fact. Kruger passed it off as an everyday occurrence. He was still young, after all.