by Hal Clement
It was big. Although, in some unexplained manner, it had buried itself in the hillside, so that only a small sector of its top-surface showed above ground, the curve of its dull-grey, irregular and knotty metallic surface revealed a diameter of more than twenty feet. There it sat, immobile, apparently harmless—like a large piece of leaden-hued pewter discarded from a New England farmhouse attic.
“We found it! We fou-ound it!” Truck chanted, and then suddenly turned deathly pale, as the terrifying significance of the find’s brooding stillness and nearness and alienness was borne in upon him.
“Get off at once!” Parsons almost shrieked the words. “You don’t know what sort of radiations may be coming from it.” Truck swayed as if in mortal terror and scrambled down. “My God!” he breathed. “I left the Geiger counter back in the trailer.”
“Get it,” Parsons shot back to him. “And get the jeep as close as you can.” Apparently whatever is inside that thing can only communicate through the radio.”
“I know—sure,” said Truck. “I—I’ll be right back with the Geiger.”
He had just turned to carry out the order, when Candace uttered a small shrill scream and cried, “Look! Hal, stay back! It’s boiling the earth around it!”
Something very strange was happening. Invisible currents were making the once-sandy soil in which the object had settled seethe like boiling water in a kettle. As Parsons pulled his wife quickly away from the area of disturbance, he thought that her use of the word “boiling” had been singularly apt. From a safe distance up the hillside, the three of them watched the ground around the visitor act as solid matter was not supposed to act.
It was Truck who first sensed the visitor’s intentions. Stabbing a large grimy forefinger at it he announced, “For Pete’s sake, he’s coming up!”
They looked on in awe as the dull-grey globe that was not from Earth slowly emerged from its bed of soil, looming larger and larger as it rose, and revealing in what appeared to be its nose a pair of opaque, circular objects that looked like eyes.
VII
THE STAR-TRAVELER already knew, of course, that he was in a valley, partway up one of the sides. The hills bounding it were not particularly high, especially by the standards of this planet. In fact, the Conservationist had a pretty accurate idea of the dimensions of the Himalayas, distant as they were—though he had been more interested in determining the rate at which they were rising. He gave the local elevations only a passing thought, then sought to examine what lay closer to his vision-outlets—outlets which the Parsons group had quite correctly labeled “eyes.”
He failed. The details five miles away were clear and clouds of what must be water or ammonia droplets hanging at still greater distances in the atmosphere were still clearer. But, as he brought his attention to objects nearer and nearer to his ship, they grew, shapeless, and increasingly harder to examine.
Cursing himself for forgetting, he recognized the reason. His eyes were perfectly good instruments—for the purpose toward which they had been designed. They were carefully shaped lenses of calcium fluoride, designed with almost a full hemisphere of field and their curved focal surface was followed faithfully by the photosensitive material of his own flesh. The tiny metallic crystals in his stony tissues would, of course, be affected electrically by light, and, like many of his race, he had learned to interpret the light-images formed by lenses.
There was just one catch. There was no provision for changing either the shape or the position of the lenses. But actually, why should there be? They were designed to enable him to determine the directions of the stars, whose distances were for all practical purposes always infinite. He had never needed focusing arrangements until now.
The eyes were a foot across and almost as great in focal length. Objects a hundred yards away were blurs. At six feet they were scarcely interruptions to the background. He could just tell, by sight, that there were moving objects in his vicinity, and get a vague idea of their size. Beyond that, details were indistinguishable.
The nearest repair-shop where his. machinery could be modified was about six thousand light-years toward the galactic center. He could, of course, pull his flesh back from one or more of the lenses until the eye involved focused at a distance of a few feet—if the situation would wait for the necessary years or centuries. However, even if the situation did wait, the natives and their machines probably wouldn’t.
He could wait until they departed, and examine them when they were far enough away. Better than this, he could fly to a distance at which they were reasonably distinct in his sight. The question raised in that connection was, of course, how the natives would react to such a move on his part. However, if he did not move, he would probably learn nothing. Therefore, he resumed his rise from the soil, cleared its surface, and hurled his vessel half a mile upward.
To observe, and, in effect, to photograph the details of what lay below took only a few microseconds. Then he moved a few hundred yards to one side and repeated the procedure. Three seconds after takeoff, he was settling back into his original location with a fairly clear picture of the strange equipment surrounding it firmly painted in his mind.
He understood now why the seismic impulses had come in pairs. Each of the machines was supported by two struts, which were so hinged as to permit several degrees of freedom of motion. During his brief period of observation, they had traveled enough—away from the point where his ship had been resting—to permit him to analyze their startling method of travel. This seemed to consist in balancing on one strut, falling in the desired direction, and catching one’s mass with the other before collapsing completely. The process was repeated cyclically.
It appeared, mathematically, that the value of the planet’s gravitational acceleration would put an upper limit on the rate of travel possible by this means. The agent found himself a little dubious about the engineering advantages of it. If one had to travel on the surface, wheels seemed easier—although an irregular surface might present further difficulties. Few Conservationists, surely, had confronted problems so difficult to resolve.
At least, he had eliminated the last possible doubt that the things were non-metallic, non-electric machines, since he had actually seen them move in a manner which verified and complemented his seismic observations. This implied that the natives were not merely cultured, but had developed a physical science equal to, perhaps greater, than that of the agent’s own race. The latter was certainly possible, since he had not the faintest idea of what was the operative principle of the devices. It was a disturbing speculation, but he refused to enlarge upon it emotionally. Oviously they had some electrical equipment. The signal detector and broadcasting device, as well as the ionization cylinder, were quite evidently as artificial as his own ship. Their science, regardless of its development, could not be entirely alien. It might be possible for him to learn something about it. If so, it was important that he begin—for the equipment needed to stop the moles would have to be obtained from these people in rather short order.
The agent examined once more, as precisely as his sensory equipment permitted, every detail of the things around him, which were now returning slowly, after their hasty withdrawal. He broadcast his “Hello” again, and carefully noted the way it affected the receiver. When the answer came, he checked with equal care the source of the modulating energy.
The result was interesting. The receiver apparently did not consider the carrier waves important. It damped them out and used, through most of its circuitry, a secondary signal consisting of the original modulations. This was caused to vary the strength of a magnetic field which, as nearly as the agent could tell, was used to impart mechanical motion to an object principally non-metallic.
He could get only a rough idea of its size and shape from the space left for it in the mechanism. The evidence seemed to indicate that the whole device simply rebroadcast the modulation of the original signal mechanically into the atmosphere.
He knew, of course, th
at a gas could carry compression waves, though it had never occurred to him that they might be of any particular use. He had simply never stopped to wonder why his method of digging was more effective on a planet with atmosphere. It did no good to blame oneself for such oversights when the fat was in the fire. Anyway, he was sure of one thing. The waves were being used to carry the signals controlling the machines. Certainly no others were.
They also served for communication, since similar waves appeared to be received by the same disc in the signal device, and were used to modulate its broadcast electromagnetic impulses. This process seemed pointless, except as a means of long-distance communication. Probably pressure waves did not transmit energy so effectively through a gas as electromagnetic radiation carried it through space. So far, so good.
It all tied in, more or less, with the evident fact that these machines were not electrical, even if it did not begin to explain how they actually worked. Some sort of more precise analysis would, of course, be needed. The metal he could detect about the things seemed quite purposeless, and he did not see that it was likely to help.
It was present in small, disconnected bits and was devoid of electrical energy, if you brushed aside the minute currents generated by its motion in the planet’s magnetic field.
The machines, then, were made virtually entirely of nonconductors, and should be about as easy for the agent to examine as a device consisting exclusively of gas jets and magnetic fields would be for a human being.
This meant that the analysis would have to be by highly indirect methods. A chemist, with his laboratory machine, might be able to do the job in microseconds. But a traveling device, like the scoutship, had no equipment designed with any such purpose in mind.
He suspected that this was one of the situations where the sensile members of his race—the great majority—would leap at the chance to show their superiority over one who was bound to a machine. It had always been that way. It was a common enough feeling among those whose lives were primarily intellectual. The doers, like the agent, countered it with a clear recognition of the necessity for their work. At the moment, however, the agent rather wished that a normal person had been present, to show his intellectual superiority.
Then he realized that his own possession of machinery did not disqualify him as an intelligent being. If a member of his race could solve this problem, it was as likely to be himself as anyone else. He would have to use all his knowledge, of course, not just the specialized information which was all the millennia of flight demanded.
Enough knowledge should be there. He had, of course, been young when he had elected this life, but he had had much thinking time before his career was actually begun. Also, there had been a good deal of time to think as he drifted among the stars, and opportunities to gather data that planetbound thinkers had never possessed.
He would have to go back to the most elemental principles of thought—if he could. First, he had decided, on the basis of what seemed adequate evidence, that the planet was inhabited—that its inhabitants used machines and, therefore, had freedom of motion—and that these machines were based on a technology almost, but not quite wholly, alien to his own.
Nevertheless, the devices must operate under the same physical laws that obtained elsewhere in the universe. This meant that they must take in some form of energy, must perform a desired action, and must eventually account for the energy as heat.
The energy was not electric or magnetic, since he could have detected the presence of that kind of energy directly. It was not gravitational, since the gravitational potential of these machines—when measured as a function of their distance from the planet’s center—had actually increased since he had first detected them. It was barely possible, of course, that some primary source beyond his detection-range might work on such a basis. But for the moment that hardly bothered him. It could be filed away for future reference.
There was almost certainly no direct mechanical link with a distant energy source. He felt sure that he would have seen any such, during his brief trip aloft.
Chemical energy, however, remained a distinct possibility. Normally—which usually meant, he reflected wryly, circumstances in which intelligence had not taken a hand—chemical reactions were too slow to provide useful energy, even though they were responsible for life. However, on a planet infested with such weirdly active carbon compounds, it would not do to be dogmatic on the matter.
It was known that reactions, in such circumstances, did go with enormous speed, though little actual quantitative work had been done on the matter of the energy involved. It was quite conceivable, in any case, that there might be some method of turning chemical directly into mechanical energy, without involving electricity as an intermediate stage.
Looked at from this viewpoint, several more possibilities as to the planet became evident. Its natives could survive, either by nature or intelligent adaptation, in an oxygen-rich atmosphere. Oxygen was one of the most virulently active elements in existence. Hence, it might not be too surprising to find such a people developing a chemical technology and bypassing the electricity a living creature should logically use—but wait. They had not bypassed electricity.
There were auxiliary machines, among the vehicles facing him, which did use it. Perhaps, these people had originally developed a normal technology, but, for some unaccountable reason, had never mastered space-flight! That was more than likely, if one assumed they did not merely tolerate oxygen, but needed it.
In that case, they would inevitably exhaust, in a relatively short time, the metal resources of a single planet.
They would be faced with the choice of developing machines that did not make demands on the metal supply, or of sinking to barbarism during the millions of years it would take new metal deposits to concentrate to usability.
This race might have succeeded in accomplishing the former—in which case, the exhaustion of the local ore veins could not be blamed on the poachers after all. The marauder might have planted the torpedoes in momentary pique, believing that a regular freighter had been there first and hoping to throw the production schedule of this planet out of step with that which had been recorded for it.
It was a very attractive idea, but the agent decided he should not go quite so far in pure speculation. There should be other possible sources of energy besides chemical activity, promising as such energy appeared to be. He could, for example, detect a pressure against his hull which seemed to be due to currents in the atmosphere. These must necessarily carry energy, though it seemed, at first estimate, that it could hardly be quantitatively adequate to run these machines.
There was nuclear energy. Obviously, these aliens did not use it directly, yet the possibility remained that it was their primary source and was stored in some non-self-destructive form within them. Strength was lent to this possibility by the presence of the ionization tube, which might well be used to locate radioactive materials. If, of course, the normal senses of the creatures were inadequate for the task. Atomic energy not under rigid control was always a rather frightening thing to contemplate, and he did not dwell on certain other unlikely possibilities concerning it.
He had already thought of solar energy, but had seen nothing to offset any of his earlier objections to this theory. On the whole, the chemical idea seemed the most worth following up.
He searched his memory for the little he knew about the highspeed chemical reactions of free-oxygen environments, and found a few helpful items. For one, they did involve solar energy—they employed it usually in breaking down water. The oxygen was freed to the surroundings, and the hydrogen combined with oxides of carbon to produce carbohydrates.
These, in turn, could react upon each other, with simple compounds and with some of the free oxygen, to produce incredibly complex substances whose detailed structure had never been worked out by any chemist of his people. This situation should, of course, result in a continual increase of free oxygen in the planet’s atmosphere at the expense
of the water.
Observation indicated that, actually, an equilibrium was usually attained in this respect. Whether the oxygen re-combined spontaneously with the hydrogen in the compounds, or whether still other high-speed reactions, of the same general type as the photosynthetic ones, did the trick, was still a matter of debate. Even the agent could understand, however, that the combination of oxygen with almost any of the complex carbon-hydrogen compounds would return the energy originally supplied by the sun.
If the compounds had any reasonable density, it should be possible to store quite a fuel supply in a very small space that way, using atmospheric oxygen to combine with it whenever desired. Even without precise figures, he felt sure that this would constitute an adequate energy-source for the machines he had been watching.
Was there anything he had overlooked? No—he was nothing if not thorough when he undertook a task of objective scientific analysis. A doer had his own pride to safeguard, and if he was not an intellectual in a strict sense, he did possess a first-rate mind.
How could this theory be checked experimentally? If it proved correct, there should be, somewhere on or within these machines, a store of hydrogen-carbon compounds. They should be absorbing atmospheric oxygen at a fairly high rate. And they should be exhausting water and, possibly, oxides of carbon.
He had no means for recognizing the hydrogen-carbon compounds, even if he found them, so there seemed little point in trying to take one of the mechanisms apart. No point even if its operator proved willing to allow it. However, there seemed to be a possible way of attacking the problem through the other facts. If an oxidizing reaction of the sort he had envisioned went on in a confined space, what would happen to the pressure? He pondered the problem.
Producing solid oxides would reduce pressure by removing oxygen. The formation of carbon dioxide would leave it unchanged, for there would be the same number of molecules after the reaction as before. Making water or carbon monoxide would give a pressure increase, since each molecule of oxygen would go into two molecules of the product.
