Iceworld

by Hal Clement

  Under the beam setting controls was a small drawer which also contained two sets of numbers — again, spatial coordinates; but this time Ken froze to attention as he realized that one set at least did not refer to planets — they contained no cyclic term. The set was short, consisting of six groups of numbers containing from six to ten digits each; but he recognized them. The first identified by spectrum a beacon star; the next three were direction cosines, giving the three-dimensional bearing to another sun; the fifth gave a distance. Normally he might not have recognized or remembered the lengthy figures; but those were the coordinates of the blazing A-class sun which warmed Sarr, his home planet. The final number was another range; and beyond question it represented the distance from the present point of observation to the listed star. Ken knew enough of the standard navigational notations to be sure of that.

  The other set of numbers, then, must give the direction of the same sun relative to some local set of coordinates; and not only was he ignorant of the coordinates, but the numbers were too long to remember. To copy them would be suicide, if anything more than commercial secrecy were involved. For long minutes Sallman Ken stood frozen in thought; then, abruptly, he slipped the sheet back into the drawer, closed the latter, and as quickly as was compatible with caution left the observatory. Since the information was there, it would not do for anyone to get the idea he had been there for any great length of time. It would be better if no one knew he had been there at all, but he had been seen on the way up the ramp. He proceeded to get back to his own quarters and assume an attitude of repose, though his mind still raced furiously.

  He knew his distance from home. Evidently the twenty-two days of the journey to this system had not been spent in straight-line flight; the distance was only two hundred twelve parsecs. Score one for Rade; that would be an expensive business precaution, but a normal criminal one.

  The direction home from this system he did not know. It did not matter too much anyway; what the Narcotics Bureau would want would be the opposite direction, on Galactic coordinates, and there would be no mathematical connection between the two except a purely arbitrary formula which would be harder to memorize than the direction itself.

  Of course, the beacon listed in the stellar coordinates was probably visible from here; but could he recognize it with any certainty without instruments? The instruments were available, of course, but it might not be wise to be caught using them. No, orientation was definitely the last job to be accomplished in his present location. At any rate, one fact had been learned and one point of probability had been added to the Rade theory. Sallman Ken decided that made a good day’s work, and allowed himself to relax on the strength of it.

  6

  Nearly three of Sarr’s thirteen-hour days passed uneventfully before the relay station circling Earth picked up the approaching torpedoes. As Feth Allmer had predicted — and Laj Drai had confirmed, after checking with his tables — the signals from the planted homing unit were coming from the dark side of the planet. Drai phoned down from the observatory to the shop, where Ken and Allmer were engaged in decelerating their missile.

  “You may as well drop straight down as soon as you swing around to the dark side,” he said. “You will pick up the beacon if you spiral in, keeping between forty and fifty-five degrees above the plane of the planet’s orbit, measured from the planet’s center. The beam can be picked up by your torpedo more than forty diameters out, so you can’t possibly miss it. You’d better ride the beam down automatically until you’re into atmosphere, then go manual and move off a couple of miles if you plan to go all the way to the ground. If the natives are camping near the beam transmitter, it would be a pity to touch off your chemicals right in their midst.”

  “True enough,” Ken replied. “Feth is swinging around into the shadow now, still about five diameters out. I wish there were a vision transmitter in that machine. Some time I’m going down close enough to use a telescope, unless someone builds a TV that will stand winter weather.”

  “You’ll get worse than frostbite,” Drai responded sincerely. “The time you were really looking at that world, you didn’t seem quite so anxious to get close to it.”

  “I hadn’t gotten curious then,” responded Ken.

  The conversation lapsed for a while, as Feth Allmer slowly spun the verniers controlling the direction of thrust from the torpedo’s drivers. The machine was, as Ken had said, cutting around into the shadow of the big planet, still with a relative speed of several miles per second to overcome. Allmer was navigating with the aid of a response-timer and directional loop in the relay station, whose readings were being reproduced on his own board; the torpedo was still too far from Earth for its reflection altimeter to be effective. For some minutes Ken watched silently, interpreting as best he could the motions of the flickering needles and deft tentacles. A grunt of satisfaction from the operator finally told him more clearly than the instruments that the beam had been reached; a snaky. arm promptly twisted one of the verniers as far as it would go.

  “I don’t see why they couldn’t power these things for decent acceleration,” Feth’s voice came in an undertone. “How much do you want to bet that we don’t run all the way through the beam before I can match the planet’s rotation? With nine-tenths of their space free for drivers and accumulators, you’d think they could pile up speed even without overdrive. These cheap—” his voice trailed off again. Ken made no reply, not being sure whether one was expected. Anyway, Allmer was too bright for his utterances to be spontaneous, and any answer should be carefully considered purely from motives of caution.

  Apparently the mechanic had been unduly pessimistic; for in a matter of minutes he had succeeded in fighting the torpedo into a vertical descent. Even Ken was able to read this from the indicators; and before long the reflection altimeter began to register. This device was effective at a distance equal to Sarr’s diameter — a trifle over six thousand miles — and Ken settled himself beside the operator as soon as he noted its reaction. There was not far to go.

  His own particular bank of instruments, installed on a makeshift panel of their own by Allmer, were still idle. The pressures indicated zero, and the temperatures were low — even the sodium had frozen, apparently. There had been little change for many hours — apparently the whole projectile was nearly in radiative equilibrium with the distant sun. Ken watched tensely as the altimeter reading dropped, wondering slightly whether atmosphere would first make itself apparent through temperature or pressure readings.

  As a matter of fact, he did not find out. Feth reported pressure first, before any of Ken’s indicators had responded; and the investigator remembered that the door was shut. It had leaked before, of course, but that had been under a considerably greater pressure differential; apparently the space around the door was fairly tight, even at the temperature now indicated.

  “Open the cargo door, please,” Ken responded to the report. “We might as well find out if anything is going to react spontaneously.”

  “Just a minute; I’m still descending pretty fast. If the air is very dense, I could tear the doors off at this speed.”

  “Can’t you decelerate faster?”

  “Yes, now. Just a moment. I didn’t want to take all night on the drop, but there’s only about twenty miles to go now. You’re the boss from here in.” The needle of the altimeter obediently slowed in its march around the dial. Ken began warming up the titanium sample — it had the highest meeting point of all. In addition, he was reasonably sure that there would be free nitrogen in the atmosphere; and at least one of the tests ought to work.

  At five miles above the ground, the little furnace was glowing white hot, judging from the amount of light striking the photocell inside the nose compartment. Atmospheric pressure was quite measurable, though far from sufficient from the Sarrian point of view, if the Bourdon gauge could be trusted; and Feth claimed to have worked out a correction table by calibrating several of them on the dark side of Planet One.

/>   “Can you hold it at this height for a while?” Ken asked. “I’m going to let this titanium act up here, if I possibly can. There’s atmosphere, and we’re high enough not to be visible, I should think.” Allmer gestured to the reading of the photocell.

  “The door is open, and that furnace is shining pretty brightly. You’d do better to shut the door, only that would keep air pretty well out. A light like that so far from the ground must show for scores of miles.”

  “I never thought of that.” Ken was a trifle startled. He thought for a moment, then, “Well, let’s close the door anyway. We have a pressure reading. If that drops, we’ll know that some sort of action is taking place.”

  “True enough.” Allmer snapped the toggle closing the door and waited silently while Ken manipulated his controls. Deprived of the opening through which a good deal of heat had been radiating, the compartment temperature began to climb. By rights, the pressure should have done the same; but to Ken’s intense satisfaction, it did not — it fell, instead. At his request, the door was opened for an instant and promptly closed again; results were consistent. The pressure popped back to its former value, then fell off once more. Apparently the titanium was combining with some gaseous component of the surrounding atmosphere, though not violently enough for the reaction to be called combustion.

  “If you’re far enough to one side of the beam, let’s go down to the surface,” the investigator finally said. “I’d like to find out what percentage of the air will react this way, and for any sort of accuracy I’ll need all the atmospheric pressure I can get to start with.”

  Feth Allmer gave the equivalent of a nod.

  “We’re a couple of miles to one side,” he said. “I can drop straight down whenever you want. Do you want the door open or closed?”

  “Closed. I’ll let the sample cool a little, so we can get normal pressure after landing without using it all up. Then I’ll warm it up again, and see how much of the air in the compartment is used up.” Feth gestured agreement, and a faint whistling became audible as the torpedo began to fall without power — like the others, it had speaker and sound pickups, which Allmer had not bothered to remove. Four miles — three — two — one — with deceptive casualness, the mechanic checked the plunge with a reading of one hundred fifty feet on the altimeter, and eased it very cautiously downward. As he did so, he gestured with one tentacle at another dial; and Ken, after a moment, understood. The projectile was already below the level of the homing station.

  “I suppose the transmitter is on a mountain, and we’re letting down into a valley,” Feth elaborated, without taking his eyes from his work.

  “Reasonable enough — this was always supposed to be a rough section of the planet,” agreed Ken. “It’s good— there’s that much less chance of being visible from a distance. What’s the matter — aren’t you down, after all?”

  The altimeter had reached zero, but nothing had checked the descent. Faint rustlings had become audible in the last few seconds, and now these were supplemented by louder snappings and cracklings. Descent ceased for a moment. Apparently an obstacle sufficient to reflect radar waves and take the machine’s weight had been encountered; but when a little downward drive was applied, the crackling progress continued for some distance. Finally, however, it ceased — noise and motion alike — even when Allmer doubled and quadrupled the power for several seconds. He opened his drive switches and turned to Ken with a gesture equivalent to a shrug.

  “We seem to be down, though I can’t guarantee it’s ground as we know it. It seems to be as low as we can get, though. There’s the door switch, in case you didn’t know. You’re on your own, unless you don’t mind my hanging around to watch. I suppose the boss will be here soon, too; he should have his machine in an orbit by this time.”

  “Sure — stick around. I’ll be glad to have you. Maybe we’ll have to move the thing around, for all I can tell at the moment.” He had opened the door as he spoke, and watched with interest as the pressure gauge snapped up to a value about two thirds of Sarr normal. At the same instant, the temperature dial of the still hot titanium furnace began to rise spontaneously — apparently the greater atmospheric density was more than able to offset the slight amount of cooling that had taken place; the metal was actually burning. Ken hastily shut the door.

  The temperature continued to rise a short distance, while the light intensity in the cargo compartment of the torpedo held at a value that would have been intense even to eyes accustomed to Sarr’s fervent sun. The most interesting information, however, came from the pressure gauge; and it was on this that Ken kept his attention glued.

  For perhaps twenty seconds the reaction continued unabated; then it began to die out, and in ten more the temperature began once more to drop. The reason was evident; pressure had dropped to less than two percent of its former value. There was literally nothing left to carry on the reaction.

  Ken emitted the booming drone from his sound-diaphragm that was the Sarrian equivalent of a whistle of surprise.

  “I knew molten titanium would react to completion in our atmosphere, but I didn’t think it would possibly do it here. I guess I was wrong — I was rather expecting a mixture of compounds, whose heats of formation would prevent any such reaction. Still, I suppose at this planet’s temperature, they wouldn’t have to be very stable from our point of view. .” his voice trailed off.

  “Means nothing to me, but it certainly burned,” Feth

  Allmer remarked. “How about your other samples? Are you going to run them off right away, or wait for things to cool down again to planet-normal?” Another dial caught Ken’s eye before he could answer.

  “Hey — who lit the sodium?” he asked, heedless of Allmer’s query. “It’s cooling now, but it must have been burning, too, for a while when there was air.”

  “Let more in and see.” The toggle snapped over, and there was a distinct popping sound as air rushed into the rear-vacuum. The sodium continued to cool.

  “Maybe a spark from the titanium pot lighted it up.” Without answering, Ken closed the door once more and began to warm up the sodium container. Apparently Feth’s suggestion was not too far from the mark; very little additional heat was needed to ignite the metal. This time the reaction stopped after pressure had dropped about a sixth. Then the door was opened again, and another touch of artificial head caused the reaction to resume. This time it continued, presumably, until the sodium was consumed.

  “I want enough material to work on when we get it back,” Ken explained. “I’m not the Galaxy’s best analytical chemist.”

  The crucible of carbon dust gave decidedly peculiar results. Something certainly happened, for the material not only maintained but even increased its temperature for some time after the heating current was cut off; but there was no evidence either of consumption or production of gas in the closed chamber. Both Ken and Feth were slightly startled. The former, in response to the mechanic’s quizzical expression, admitted the fact was probably significant but could offer no explanation.

  Samples of iron, tin, lead, and gold followed in due course. None of these seemed greatly affected by the peculiar atmosphere at any temperature, with the possible exception of the iron; there the pressure drop was too small to be certain, since in each of these cases the heating had caused an increase in pressure which had to be allowed for. Magnesium behaved remarkably like sodium, except that it burned even more brightly than the titanium.

  Here again Ken decided to finish off the metal by relighting it with the door open; and here the testing program received a sudden interruption.

  Both Sarrians were perfectly aware that with the door open a beam of light must be stabbing out into the darkness. Both had ceased to worry about the fact; it had been equally true, though perhaps the radiance was fainter, with the blazing sodium and almost as much so when the sheer heat of the samples of iron and gold had been exposed. They had completely ceased to worry about being seen; a full hour had already passed since the
y had landed the torpedo, owing to the cooling periods necessary between tests, and there had been no sign that any attention had been attracted. Ken should have remembered the difficulty that had been encountered in reaching the ground.

  The possibility was brought back to their attention with the relighting of the magnesium sample. As the photocell reported the reestablishment of combustion, a shrill sound erupted from the speaker above the control board and echoed through the ship. Neither had to be told what it was; both had heard the recordings of the voice of the Third Planet native who had found the original torpedo.

  For an instant both remained frozen on their racks, exploring mentally the possibilities of the situation. Feth made a tentative gesture toward the power switches, only to be checked by an imperious snap of Ken’s tentacles.

  “Wait! Is our speaker on?” The words were whispered.

  “Yes.” Feth pulled a microphone down to chest level and retreated a step. He wanted no part in what Ken seemed about to do. Sallman himself, however, had once more become completely absorbed in the mystery of the World of Ice, to the exclusion of all other matters; he saw no reason for leaving the site where his activities had been discovered. It did not even occur to him not to answer the native who appeared to have made the discovery. With his speaking diaphragm close to the microphone, he emulated the “boss” of so many years before, and tried to imitate the sounds coming from the speaker.