by Hal Clement
They were not traveling, as he has deduced already. Furthermore, a fourth machine, hitherto unnoticed, had joined them. All four had settled to the ground, so that their main frames took the weight normally carried by the traveling struts, which appeared merely to be propping the roughly cylindrical shapes in a more or less vertical attitude. The different ways in which this was accomplished, in different cases, did not surprise the agent. It would not have occurred to him to expect any two machines to be precisely alike, except perhaps in such standard subcomponents as relays. And it was, of course, fortunate that every new development happened in sequence, enabling him to analyze carefully as he went along.
The upper struts were moving rather aimlessly in general, but it did not take long for him to judge that their primary function was manipulation. The objects being handled at the moment were for the most part meaningless—apparently stones, bits of metal without obvious function, utterly unrecognizable objects which might be aggregates of the unfamiliar carbon compounds, though the agent knew no way to prove it. There were one or two exceptions. The device that had projected the slug of metal at his hull was easy to recognize, even though he had not perceived all of it at the time it was being used.
He tried to decide what parts of the machines functioned as their eyes, and was able to find them. It was not difficult, for no other portion was reasonably transparent. He discovered that all these vision organs were now turned toward him, but saw nothing surprising in the fact. The operators must have been familiar with the rest of the landscape, and did not expect anything of interest to show up on it.
Then the traveler noticed that all four of the machines were rising to their struts. As he watched, they began to move toward him.
At the same time, one of them extended a handling member toward a smaller fabrication, which almost immediately turned out to be another electromagnetic radiator. It was put to use at once, being swiftly raised to the upper part of the largest machine in the vicinity of the eyes, while a minor appendage of the handling limb which held it closed a switch.
This started the carrier frequency, after a delay which the agent was able to identify as due to the slow growth of the ion-clouds in portions of the apparatus—apparently they were produced by heating metal—and to the inherent lag of mechanical operations. The relays in the device were fantastically huge. They took whole milliseconds to operate and since they rather obviously had components consisting of multicrystalline pieces of metal, they must have had a sharply limited service life.
Evidently the natives had not gone far enough with metal technology even to get the most out of one world’s supplies. This was a side-issue, however. A far more interesting development involved the modulation of the carrier. The agent found it possible actually to see the way this was being carried out.
An opening in the machine, not far below the eyes, rimmed with a remarkably flexible substance at whose nature he could only guess, began to open, shut and go through a series of changes of shape. He found it possible to correlate many of these contortions with the modulation of the electromagnetic signal. Apparently the opening was part of a device for generating pressure-wave patterns in the atmosphere.
The agent supposed that whatever plan the distant observers had been maturing must be moving into action, and he wondered what the machines were about to do.
He was naturally a little surprised, since he had not expected any developments of this sort so soon.
Then he wondered still more, for the advance toward him which had been commenced halted, as suddenly as it had begun. Whatever had motivated them had either ceased—or the whole affair was part of an operation whose nature was still obscure. It would be the better part of valor to assume the latter, he decided.
He watched all four of the machines with minute care. They were now balanced on their support struts. They were neither advancing nor retreating, and the upper members were moving in their usual random fashion. All eyes were still fixed on his ship.
Then he noticed that the pressure-wave assemblies of all four were functioning, although three did not possess any broadcaster whose signal could be modulated. He watched them in fascination. Sometimes—usually, in fact—only one would be generating waves. At others, two, three or all four would be doing so. Even the one with the broadcaster did not always have its main switch closed at such times. Something a little peculiar was definitely occurring.
It had already occurred to the agent that the atmospheric waves carried the control impulses for these machines. Why should the machines themselves be emitting them, however? Receivers should be enough for such machines. Then he recalled another of his passing thoughts, which might serve as an explanation. Perhaps there was only one operator for all of them. And after all, why not? It might be better to think of the whole group as a single machine.
In that case, the pressure waves, traveling among its components, might be coordination signals. They just might be. At any rate, some testing could be done along this line. Whatever limitations he and his ship might have on this world, he could at least set up pressure waves in its atmosphere. Perhaps he could take over actual control of one or more of these assemblies. He had had the idea earlier, in connection with radio waves, and nothing much had come of it. But there seemed no reason not to try it again with sound. Nothing could surpass the experimental method when it was pursued with one strongly likely probability in mind.
A logical pattern to use would be the one that had been broadcast back to the distant observer a few moments before. It had been connected with a fairly simple, definite series of actions, and he had both heard and seen its production. He tried it, causing his hull to move in the, complex pattern his memory had recorded a few seconds before. He tried it a second time.
“The thing’s howling like a fire-siren!”
Just as when he had tried the same test with radio waves, there was no doubt that an effect had been produced, though it was not quite the effect the agent had hoped for. The handling appendages on all four of the things dropped whatever they were holding and snapped toward the upper part of their bodies. Once there, their flattened tips pressed firmly against the sides of the turrets on which their eyes were mounted.
For a moment, none of them produced any waves of its own. Then, the one with the broadcaster began to use it at great length. The agent wondered whether or not to attempt reproduction of the entire pattern it used this time, and decided against it. It was far more likely to be a report than involved in control. He decided to wait and see whether any other action ensued.
What did result might have been foreseen even by one as unfamiliar with mankind as the Conservationist. The machine with the broadcaster began producing more pressure waves, watching the ship as it did so. The agent realized, almost at once, that the controller was also experimenting. He regretted that he could not receive the waves directly, and wondered how he could make the other—or others—understand that their signals should be transmitted electromagnetically.
As a matter of fact, the agent could have detected the sound waves perfectly well, had it occurred to him to extend one of his seismic receptor-rods into the air. A sound wave carries little energy and only a minute percentage of that will pass into a solid from a gas. But an instrument capable of detecting the seismic disturbance set up by a walking man a dozen miles away is not going to be bothered by quantitative problems of that magnitude. However, this fact never dawned on the agent. Yet few would deny that he had done very well.
As it happened, no explanation was necessary for the hidden observer. He must have remembered, fairly quickly, that all the signals the agent had imitated had been radioed, and drawn the obvious conclusion. At any rate, the broadcaster was very shortly pressed into service again. A signal would be transmitted by radio, and the agent would promptly repeat it in sound waves.
Since the Conservationist had not the faintest idea of the significance of any of the signals this was not too helpful—but the native had a way ar
ound that. A machine advanced to the hull of the ship and scraped the clay from one of its eyes. The particular eye was the most conveniently located one, to the agent’s annoyance. But fortunately it was not the only one through which he could see the things.
Then, an ordered attempt was begun, to provide him with data which would permit him to attach meanings to the various signal groups. Once he had grasped the significance of pointing, matters went merrily on for some time.
They pointed at rocks, mountains, the sun, each other—each had a different signal group, confirming the agent’s earlier assumption that they were not identical devices. But there also seemed to be a general term which took them all in.
He was not quite sure whether this term stood for machines in general, or could be taken as implying that the devices present were part of a single assembly, as he had suspected earlier. While the lessons went on, two of them wandered about the valley seeking new objects to show him. One of these objects proved the spark for a very productive line of thought.
Its shape, when it was brought back and shown to him, was as indescribable as that of many other things he had been shown by them. Its color was bright green and the agent, perceiving a rather wider frequency band than was usable by human eyes, did not see it or think of it as a green object. He narrowed its classification down to a much finer degree.
He did not know the chemical nature of chlorophyll, but he had long since come to associate that particular reflection spectrum with photosynthesis. The thing did not seem to possess much rigidity. Its bulbous extensions sagged away from either side of the point where it was being supported. The handling extension that gripped it seemed to sink slightly into its substance.
He had never seen such a phenomenon elsewhere, and had no thought or symbol from the term pulpy. However, the concept itself rang a bell in his mind, for the machines facing him seemed fabricated from material of a rather similar texture. It was a peculiarity of their aspect that had been bothering him subconsciously ever since he had seen them moving. Now a nagging puzzlement—subconscious frustration was always unpleasant—was lifted from his mind.
The connection was not truly a logical one. Few new ideas have strictly logical connection with pre-existing knowledge. Imagination follows its own paths. Nevertheless, there was a connection, and, from the instant the thought occurred to him, the agent never doubted seriously that he was essentially correct. The natives of this planet did not merely use active carbon compounds as fuel for their machines. They constructed the machines themselves of the same sort of materials.
Under the circumstances it was a reasonable thing to do—if one could succeed at it. The reactions of such chemicals were undoubtedly rapid enough to permit as speedy action as anyone could desire—at least as fast as careful thought could control. The agent’s race had long since learned the dangers inherent in machines capable of responding to casual, fleeting thoughts and his ship’s pickup-circuits were less sensitive, by far, than they might have been.
It was obvious why these devices were controlled from a distance, instead of being ridden by their operators, too. There must be some dangerous reactions, indeed, going on inside them. The agent decided it was just as well that his temporary prisoner had merely looked at the inside of his ship, without touching anything, and resolved to take no more such chances.
At any rate, there should be no more need for that sort of experiment. Language lessons were well under way. He had recorded a good collection of nouns, some verbs the machines had acted out, even an adjective or two. He was puzzled by the tremendous length of some of the signal groups, and suspected them of being descriptions, rather than individual basic words.
But even that theory had difficulties. The signal which, apparently, stood for the machines themselves, one which should logically have called for a rather long and detailed description, was actually one of the shortest—though even this took several hundred milliseconds to complete. The agent decided that there was no point in trying to deduce grammar rules. He could communicate with memorized symbols, and they would have to suffice.
Of course, the symbols that could be demonstrated on the spot were hardly adequate to explain the nature of Earth’s danger. The Conservationist had long since decided just what he wished to say in that matter, and was waiting impatiently for enough words to let him say it.
It gradually became evident, however, that if he depended on chance alone to bring them into the lessons he was going to wait a long time. This meant little to him, personally. But the mole robots were not waiting for any instruction to be completed. They were burrowing on. The agent tried to think of some means for leading the lessons in the desired direction.
This took a good deal of imagination on his part, obvious as his final solution would seem to a human being. The idea of having to learn a language had been utterly strange to him, and he was still amazed at the ingenuity the natives showed in devising a means for teaching one. It was some time before it occurred to him that he might very well perform some actions, just as they were doing. If he did not follow his own acts with signal groups of his own, these natives might not understand that he wanted theirs. The time had come for a more direct and audacious approach to the entire problem, and at the thought of what he was about to do his spirits soared.
He did it. He lifted the ship a few feet into the air, settled back to show that he was not actually leaving, and then rose again. He waited, expectantly.
“Up.”
“Rise.”
“Go.”
Each of the watching machines emitted a different signal, virtually simultaneously. Three of them came through very faintly, since the speakers were some distance from the radio. But he was able to correlate each with the lip-motions of its maker. He was not too much troubled by the fact that different signals were used. He was more interested in the evidence that a different individual was controlling each machine. This was a little confusing, in view of his earlier theories. But he stuck grimly to the problem at hand.
VI
The agent dropped back to the ground and went through his actions again. This time only the individual with the radio spoke. The word it used was rise. This was not the one it had used the other time. To make sure, the agent went through the act still again, and got the same word. Evidently, once their minds were made up, they intended to stick to their decisions. What could he think?
Then he tried burrowing into the ground, which seemed a useful action to be able to mention. The word given on the radio was dig, though two of the other machines apparently had different ideas once more.
It did not occur to him that these things might be detecting the by-products of his digging as well as his deliberate attempts to produce sound waves, or that his efforts to focus his third eye lens, a little while before, had actually been the cause of their sudden interest in his ship at that moment. He was much too pleased with himself at this point to entertain such extraneous ideas.
Having taken over the initiative in the matter of language lessons, he concentrated on the words he wanted, and, within a fairly short time, felt sure that he could get the basic facts of Earth’s danger across to his listeners. After all, only four signal groups were involved in the concept. Satisfied that he had these correctly, he proceeded to use them together. In his progress now he felt the surge of a very personal kind of pride.
“Man dig—mountain rise.”
For some unexplained reason the listening machines did not burst into frantic activity at the news. For a moment, he hoped that the controllers had turned to more suitable equipment to cope with the danger, leaving inactive that which they had been using. But he was quickly disabused of that bit of wishful thinking. The machine with the radio began to speak again.
“Man dig.” It bent over and began to push the loose dirt aside with the flattened ends of its upper struts. The agent realized, with some dismay, that its operator must suppose he was merely continuing the language lesson. He spoke again, more loud
ly, the two signal groups which the other seemed to be ignoring.
“Mountain rise.”
All the machines looked at the hill across the valley, but nothing constructive seemed likely to come from that. If they waited for that one to rise noticeably, it would be too late to do anything about enlightening them as to the robots. He tried, frantically, to think of other words he had learned, or combinations which would serve his purpose. One seemed promising to him.
“Mountain break—Earth break—man break.” The verb did not quite fit what was to happen, according to its earlier demonstration, but it did carry an implication of destruction, at least. His audience turned back to the ship, but gave no obvious sign of understanding.
He thought of another concept which might apply, but no word for it had yet appeared in the lessons. So, to illustrate it, he turned his ship’s weapon on a patch of soil, a hundred yards from the bow. Twenty seconds’ exposure to that needle of intolerable flame reduced the ground which it struck to smoking lava.
Even before he had finished the word fire came from one of the watchers. The observer made no comment on the fact that the tube which threw slugs of metal had been leveled at his hull, during most of the performance. He simply made use of the new word.
“Man dig—Earth fire—mountain fire.”
One of the machines produced its ionization tube and cautiously approached the patch of cooling slag. This had a slight amount of radioactivity from the beam, and its effect on the tube gave rise to much mutual signaling on the part of the machines. This culminated in a lengthy radio broadcast, not addressed to the agent. Then the language lessons were resumed, with the natives once more taking the initiative.
“Iron—copper—lead.” Samples were shown individually.
“Metal.” All the samples were shown together.
“Melt” This was demonstrated, when they finally made him understand that the weapon should be used again.