Iceworld

by Hal Clement

  “But your ideas on the native chemistry could hardly tell — or I suppose perhaps they could. Still, Drai knows perfectly well I’ve never worked for another trading company and I’m not a trader myself — why should I be treated like a commercial spy? I don’t care particularly what your stuff is — I’m interested in the planet.”

  “I don’t doubt it. Just the same, if I ever make any more slips like that, please keep whatever you learn to yourself. I thought there’d be a nuclear explosion when Drai walked in with you yelling ‘Tofacco!’ into the mike.”

  “He couldn’t really do much, though.” This was a ranging question; Ken had started to think again.

  “Well—” Feth was cautious about his answer—”he’s the boss, and this isn’t such a bad job. Just do the favor, if you don’t mind.” He turned back to the armor, with an expression on his face which indicated he was through talking for the time being. Ken found himself unable to get anything definite from the mechanic’s answer.

  He didn’t think about it very hard anyway, for the other problem proved too interesting. Feth was certainly a good mechanic; as good as some rated engineers Ken had known. He had opened the armor completely and removed all the service plates, and started the job by giving it a full overhaul inspection. That completed, he refilled the zinc circulating system and replaced and safe-tied the plates he had removed, but left the armor itself open. One eye rolled questioningly at the watcher, and he spoke for the first time in two hours.

  “Have you any ideas about instrument arrangement? You know best what you want to find out.”

  “Well, all we really need to know is whether the suit can maintain temperature and pressure. I suppose a single pressure gauge anywhere inside, and thermometers at the extremities, would tell enough. Can you use telemetering instruments, or will we have to wait until this torpedo gets back, too?”

  “I’m afraid we’ll have to wait. The instruments themselves would be easy enough to install, but the voice transmitter in the armor couldn’t handle their messages. I can put a multiple recorder in the body, connect the instruments to that, and arrange so you can turn it on and off by remote control — I’ll simply tie it in to one of the suit controls. I suppose you’ll want to be able to manipulate the suit heaters, as well?”

  “Yes. If it takes anywhere near full power to maintain liveable temperature, we ought to know it. I suppose extra heaters could be installed, if necessary?”

  “I expect so.” For the first time, Feth wore an expression approximating a grin. “I could probably mount blast furnaces on the feet. I’m not so sure you could walk around with them.”

  “Even if I can’t I can at least see.”

  “If you don’t have the same trouble with your visor that I did with TV tubes. Even quartz has its limitations.”

  “I still think it can take it. Anyway, it won’t cost us anything to find out. Let’s go ahead and mount those instruments — I’m rather curious to see which of us is right. Is this recorder all right?” He took from a cabinet a minute machine whose most prominent feature was the double reel of sensitized tape, and held it up as he spoke. Feth glanced at it.

  “Only one record. Get an L-7. You can recognize it by the reel — its tape is about five times as wide. I’m using the single barometer you suggested, and thermometers in head, trunk, one foot, and one sleeve as far out as I can mount it. That leaves a free band on the tape that you can use for anything you want.” The mechanic was working as he spoke, clamping tiny instruments from a well-stocked supply cabinet into the places he had mentioned. For a moment Ken wondered whether the existence of this more than adequate instrument stock did not invalidate his argument about the lack of scientific facilities; then he recognized that all the devices were perfectly standard engineering instruments, and represented nothing but a respectable financial outlay. Anyone could buy and almost anyone could use them.

  In spite of Feth’s evident skill, the job was a long one. They did not sleep, being Sarrians, but even they had to rest occasionally. It was during one of these rests that Ken happened to notice the time.

  “Say,” he remarked to his companion, “it must be daylight on that part of the planet by now. I wonder if Drai has made his landing yet?”

  “Very probably,” Feth replied, one eye following Ken’s gaze toward the clock. “He is more than likely to be back in space again — he doesn’t waste much time as a rule.”

  “In that case, would I be likely to be skinned for dropping in to the observatory?” Feth gazed at him narrowly for long enough to let Ken regret the question.

  “I probably would be if Drai found out I’d encouraged you,” was the answer. “I think it would be better if you stayed here. There’s plenty for us to do.” He rose and returned to his labors, although the rest period had scarcely started. Ken, realizing he did not intend to say any more, joined him.

  The work turned out to be timed rather nicely. By the time the armor had survived a one-hour leakage and radiation-loss test in the vacuum of the shadowed airlock, had been clamped to the load rings of another torpedo, and launched into the void on automatic control, the other projectile was on the point of landing. The automatic control, in fact, was necessary — the second missile could not be handled by radio until the first had been docked, since the other controlling station was still being used by Drai to bring his own load back to Mercury.

  A single rest period fitted nicely between the launching of the suit and the landing of the mobile laboratory; and Ken was awaiting the latter with eagerness when it finally drifted through the air lock under Feth’s expert control. He would have pounced on it at once, but was restrained by a warning cry from the mechanic.

  “Hold on! It’s not as cold as it was out on Planet Three, but you’ll still freeze to it. Look!” A tentacle waved toward the gleaming hull, on which drops of liquid sulfur were condensing, running together and trickling to the floor, where they promptly boiled away again. “Let that stop, first.”

  Ken stopped obediently, feeling the icy draft pour about his feet, and backed slowly away. The air that reached him was bearable, but the hull of the torpedo must be cold enough to freeze zinc, if it had reached radiative equilibrium for this distance from the sun.

  Long minutes passed before the metal was warmed through and the drip of liquid sulfur ceased. Only then did Feth open the cargo door, whereupon the process was repeated. This time the straw-colored liquid made a pool on the floor of the cargo compartment, flooding around the crucibles and making Ken wonder seriously about the purity of his samples. He turned on all the heaters at low strength to get rid of the stuff as fast as possible. Since there was a serious chance of further reaction with the air if a high temperature were attained, he opened the switches again the moment the hissing and bubbling of boiling air ceased; and at last he was free to examine his results. As Roger Wing could have told him, they were quite a sight!

  9

  Some of the little pots were full; most of these appeared to be unchanged. Others, however, were not. The contents of most of these were easy to find, but Ken could see that they were going to be hard to identify.

  A white powder was literally over everything, as Roger had already seen. The yellow flecks of sodium peroxide were turning grayish as they decomposed in the heat. The gold crucible had been pulled from its base, but was otherwise unchanged; the iron had turned black; sodium, magnesium and titanium had disappeared, though the residue in each crucible gave promise that some of the scattered dust could be identified. There was still carbon in the container devoted to that substance, but much less of it than there had been.

  All these things, however, interesting and important as they might be, only held the attention of Feth and Ken for a moment; for just inside the cargo door, imprinted clearly in the layer of dust, was a mark utterly unlike anything either had ever seen.

  “Feth, dig up a camera somewhere. I’m going to get Drai.” Ken was gone almost before the words had left his diaphragm, and for
once Feth had nothing to say. His eyes were stall fixed on the mark.

  There was nothing exactly weird or terrifying about it; but he was utterly unable to keep his mind from the fascinating problem of what had made it. To a creature which had never seen anything even remotely like a human being, a hand print is apt to present difficulties in interpretation. For all he could tell, the creature might have been standing, sitting, or leaning on the spot, or sprawled out in the manner the Sarrians substituted for the second of those choices. There was simply no telling; the native might be the size of a Sarrian foot, making the mark with his body — or he might have been too big to get more than a single appendage into the compartment. Feth shook his head to clear it — even he began to realize that his thoughts were beginning to go in circles. He went to look for a camera.

  Sallman Ken burst into the observatory without warning, but gave Drai no chance to explode. He was bursting himself with the news of the discovery — a little too much, in fact, since he kept up the talk all the way back to the shop. By the time they got there, the actual sight of the print was something of an anticlimax to Drai. He expressed polite interest, but little more. To him, of course, the physical appearance of Earth’s natives meant nothing whatever. His attention went to another aspect of the compartment.

  “What’s all that white stuff?”

  “I don’t know yet,” Ken admitted. “The torpedo just got back. It’s whatever Planet Three’s atmosphere does to the samples I sent down.”

  “Then you’ll know what the atmosphere is before long? That will be a help. There are some caverns near the dark hemisphere that we’ve known about for years, which we could easily seal off and fill with whatever you say. Let us know when you find out anything.” He drifted casually out of the shop, leaving Ken rather disappointed. It had been such a fascinating discovery.

  He shrugged the feeling off, collected what he could of his samples without disturbing the print, and bore them across the room to the bench on which a makeshift chemical laboratory had been set up. As he himself had admitted, he was not an expert analyst; but compounds formed by combustion were seldom extremely complex, and he felt that he could get a pretty good idea of the nature of these. After all, he knew the metals involved — there could be no metallic gases except hydrogen in Planet Three’s atmosphere. Even mercury would be a liquid, and no other metal had a really high vapor pressure even at Sarrian temperature. With this idea firmly in mind like a guiding star, Ken set blithely to work.

  To a chemist, the work or a description of it would be interesting. To anyone else, it would be a boringly repetitious routine of heating and cooling, checking for boiling points and melting points, fractionating and filtering. Ken would have been quicker had he started with no preconceived notions; but finally even he was convinced. Once convinced, he wondered why he had not seen it before.

  Feth Allmer had returned long since, and photographed the hand print from half a dozen angles. Now, seeing that Ken had stopped working, he roused himself from the rack on which he had found repose and approached the work bench.

  “Have you got it, or are you stumped?” he queried.

  “I have it, I guess. I should have guessed long ago. It’s oxygen.”

  “What’s so obvious about that? Or, for that matter, why shouldn’t it be?”

  “To the latter question, no reason. I simply rejected it as a possibility at first because it’s so active. I never stopped to think that it’s little if any more active at that temperature than sulfur is at ours. It’s perfectly possible to have it free in an atmosphere — provided there’s a process constantly replacing what goes into combination. You need the same for sulfur. Blast it, the two elements are so much alike! I should have thought of that right away!”

  “What do you mean — a replacement process?”

  “You know we breath sulfur and form sulfides with our metabolic processes. Mineral-eating life such as most plants, on the other hand, breaks down the sulfides and releases free sulfur, using solar energy for the purpose. Probably there is a similar division of life forms on this planet — one forming oxides and the other breaking them down. Now that I think of it, I believe there are some micro-organisms on Sarr that use oxygen instead of sulfur.”

  “Is it pure oxygen?”

  “No — only about a fifth or less. You remember how quickly the sodium and magnesium went out, and what the pressure drop was with them.”

  “No, I don’t, and I can’t say that it means much to me anyway, but I’ll take your word for it. What else is there in the atmosphere? The titanium took about all of it, I do remember.”

  “Right. It’s either nitrogen or some of its oxides — I can’t tell which without better controlled samples for quantity measurement. The only titanium compounds I could find in that mess were oxides and nitrides, though. The carbon oxidized, I guess — the reason there was no pressure change except that due to heat was that the principal oxide of carbon has two atoms of oxygen, and there is therefore no volume change. I should have thought of that, too.”

  “I’ll have to take your word for that, too, I guess. All we have to do, then, is cook up a four-to-one mixture of nitrogen and oxygen and fill the caves the boss mentioned to about two-thirds normal pressure with it?”

  “That may be a little oversimplified, but it should be close enough to the real thing to let this tofacco stuff grow — if you can get specimens here alive, to start things off. It would be a good idea to get some soil, too — I don’t suppose that powdering the local rock would help much. I may add in passing that I refuse even to attempt analyzing that soil. You’ll have to get enough to use.” Feth stared.

  “But that’s ridiculous! We need tons, for a decent-sized plantation!” Sallman Ken shrugged.

  “I know it. I tell you clearly that it will be easier to get those tons than to get an accurate soil analysis out of me. I simply don’t know enough about it, and I doubt if Sarr’s best chemist could hazard a prediction about the chemicals likely to be present in the solid state on that planet. At that temperature, I’ll bet organic compounds could exist without either fluorine or silicon.”

  “I think we’d better get Drai back here to listen to that. I’m sure he was planning to have you synthesize both atmosphere and soil, so that we could set up the plantation entirely on our own.”

  “Perhaps you’d better. I told him my limitations at the beginning; if he still expects that, he has no idea whatever of the nature of the problem.” Feth left, looking worried, though Ken was unable to understand what particular difference it made to the mechanic. Later he was to find out.

  The worried expression was still more evident when Feth returned.

  “He’s busy now. He says he’ll talk it over with you after that suit comes back, so that any alternatives can be considered, too. He wants me to take you out to the caves so you can see for yourself what he has in mind for making them usable.”

  “How do we get there? They must be some distance from here.”

  “Ordon Lee will take us around in the ship. It’s about two thousand miles. Let’s get into our suits.”

  Ken heroically swallowed the impulse to ask why the whole subject should have come up so suddenly in the midst of what seemed a totally different matter, and went to the locker where the space suits were stowed. He more than suspected the reason, anyway, and looked confidently forward to having the trip prolonged until after the return of the trading torpedo.

  His attention was shifted from these matters as he stepped onto the surface of Mercury, for the first time since his arrival at the station. The blistered, baked, utterly dry expanse of the valley was not particularly strange to him, since Sarr was almost equally dry and even hotter; but the blackness of the sky about the sun and the bareness of the ground contributed to a dead effect that he found unpleasant. On Sarr, plant life is everywhere in spite of the dryness; the plants with which Ken was familiar were more crystalline than organic and needed only the most minute amounts of liqu
id for their existence.

  Also, Sarr has weather, and Mercury does not. As the ship lifted from the valley, Ken was able to appreciate the difference. Mercury’s terrain is rugged, towering and harsh. The peaks, faults and meteor scars are unsoftened by the blurring hand of erosion. Shadows are dark where they exist at all, relieved only by light reflected from nearby solid objects. Lakes and streams would have to be of metals like lead and tin, or simple compounds like the “water” of Sarr — copper chloride, lead bromide, and sulfides of phosphorus and potassium. The first sort are too heavy, and have filtered down through the rocks of Mercury, if they ever existed at all; the second are absent for lack of the living organisms that might have produced them. Sallman Ken, watching the surface over which they sped, began to think a little more highly even of Earth.

  A vessel capable of exceeding the speed of light by a factor of several thousand makes short work of a trip of two thousand miles, even when the speed is kept down to a value that will permit manual control. The surface was a little darker where they landed, with the sun near the horizon instead of directly overhead and the shadows correspondingly longer. It looked and was colder. However, the vacuum and the poor conducting qualities of the rock made it possible even here to venture out in ordinary space suits, and within a few moments Ken, Feth and the pilot were afoot gliding swiftly toward a cliff some forty feet in height.

  The rock surface was seamed and cracked, like nearly all Mercurian topography. Into one of the wider cracks Lee unhesitatingly led the way. It did not lead directly away from the sun, and the party found itself almost at once in utter darkness. With one accord they switched on their portable lamps and proceeded. The passage was rather narrow at first, and rough enough on both floor and walls to be dangerous to space suits. This continued for perhaps a quarter of a mile, and quite suddenly opened into a vast, nearly spherical chamber. Apparently Mercury had not always been without gases — the cave had every appearance of a bubble blown in the igneous rock. The crack through which the explorers had entered extended upward nearly to its top, and downward nearly as far. It had been partly filled with rubble from above, which was the principal reason the going had been so difficult. The lower part of the bubble also contained a certain amount of loose rock. This looked as though it might make a climb down to the center possible, but Ken did not find himself particularly entranced by the idea.