Hal Clement - Cycle of Fire

“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.