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Published 4 March

"Uncommon Sense" (1945) by Hal Clement

This interesting tale of conflict and survival in a hostile and unknown land was first published in the September 1945 issue of the (great) Astounding Science-Fiction magazine, with the striking illustrations by Williams that we have reproduced here.

Its author Hal Clement [1] (1922-2003) was a trained astrophysicist who brought an emphasis on the "science" part of science-fiction that was particularly effective, interesting and convincing in this quite perfect little story that has so well passed the test of time.

He was serving as a pilot in the US Air Force at the time of publication of this story, and had flown dozens of combat missions during the war in Europe. He later retired with the rank of Colonel.

e-book versions of the story are available for downloading below


"So you’ve left us, Mr. Cunning­ham!" Malmeson’s voice sounded rougher than usual, even allowing for headphone distortion and the ever-present Denebian static. "Now, that’s too bad. If you’d chosen to stick around, we would have put you off on some world where you could live, at least. Now you can stay here and fry. And I hope you live long enough to watch us take off—without you!"
Laird Cunningham did not bother to reply. The ship’s radio compass should still be in working order, and it was just possible that his erstwhile assistants might start hunting for him, if they were given some idea of the proper direction to begin a search. Cunningham was too satisfied with his present shelter to be very anxious for a change. He was scarcely half a mile from the grounded ship, in a cavern deep enough to afford shel­ter from Deneb’s rays when it rose, and located in the side of a small hill, so that he could watch the activities of Malmeson and his com­panion without exposing himself to their view.
In a way, of course, the villain was right. If Cunningham per­mitted the ship to take off without him, he might as well open his face plate; for, while he had food and oxygen for several days’ normal consumption, a planet scarcely larger than Luna, baked in rays of one of the fiercest radiating bodies in the galaxy, was most unlikely to provide further supplies when these ran out. He wondered how long it would take the men to discover the damage he had done to the drive units in the few minutes that had elapsed between the crash landing and their breaking through the con­trol room door, which Cunningham had welded shut when he had dis­covered their intentions. They might not notice it at all; he had severed a number of inconspicuous connections at odd points. Perhaps they would not even test the drivers until they had completed repairs to the cracked hull. If they didn’t, so much the better.
Cunningham crawled to the mouth of his cave and looked out across the shallow valley in which the ship lay. It was barely visible in the starlight, and there was no sign of artificial luminosity to sug­gest that Malmeson might have started repairs at night. Cunning­ham had not expected that they would, but it was well to be sure. Nothing more had come over his suit-radio since the initial outburst, when the men had discovered his departure; he decided that they must be waiting for sunrise, to en­able them to take more accurate stock of the damage suffered by the hull.
He spent the next few minutes looking at the stars, trying to ar­range them into patterns he could remember. He had no watch, and it would help to have some warning of approaching sunrise on succeed­ing nights. It would not do to be caught away from his cave, with the flimsy protection his suit could afford from Deneb’s radiation. He wished he could have filched one of the heavier work suits; but they were kept in a compartment for­ward of the control room, from which he had barred himself when he had sealed the door of the latter chamber.
He remained at the cave mouth, lying motionless and watching alter­nately the sky and the ship. Once or twice he may have dozed; but he was awake and alert when the low hills beyond the ship’s hull caught the first rays of the rising sun. For a minute or two they seemed to hang detached in a black void, while the flood of blue-white light crept down their slopes; then, one by one, their bases merged with each other and the ground below to form a connected landscape. The silvery hull gleamed brilliantly, the reflection from it lighting the cave behind Cunningham and making his eyes water when he tried to watch for the opening of the air lock.
He was forced to keep his eyes elsewhere most of the time, and look only in brief glimpses at the dazzling metal; and in consequence, he paid more attention to the de­tails of his environment than he might otherwise have done. At the time, this circumstance annoyed him; he has since been heard to bless it fervently and frequently.
Although the planet had much in common with Luna as regarded size, mass, and airlessness, its land­scape was extremely different. The daily terrific heatings which it un­derwent, followed by abrupt and equally intense temperature drops each night, had formed an excellent substitute for weather; and eleva­tions that might at one time have rivaled the Lunar ranges were now mere rounded hillocks, like that con­taining Cunningham’s cave. As on the Earth’s moon, the products of the age-long spalling had taken the form of fine dust, which lay in drifts everywhere. What could have drifted it, on an airless and consequently windless planet, struck Cunningham as a puzzle of the first magnitude; and it bothered him for some time until his attention was taken by certain other objects upon and between the drifts. These he had thought at first to be outcrop­pings of rock; but he was at last convinced that they were specimens of vegetable life—miserable, lichenous specimens, but nevertheless vegetation. He wondered what liquid they contained, in an environ­ment at a temperature well above the melting point of lead.

The discovery of animal life—medium-sized, crablike things, covered with jet-black integument, that began to dig their way out of the drifts as the sun warmed them—completed the job of dragging Cunningham’s attention from his immediate problems. He was not a zoologist by training, but the sub­ject had fascinated for years; and he had always had money enough to indulge his hobby. He had spent years wandering the Galaxy in search of bizarre life forms—proof, if any were needed, of a lack of scientific training—and terrestrial museums had always been more than glad to accept the collections that resulted from each trip and usually to send scientists of their own in his footsteps. He had been in physical danger often enough, but it had always been from the life he studied or from the forces which make up the interstellar trav­eler’s regular diet, until he had overheard the. conversation which informed him that his two assistants were planning to do away with him and appropriate the ship for un­specified purposes of their own. He liked to think that the prompt­ness of his action following the discovery at least indicated that he was not growing old.
But he did let his attention wan­der to the Denebian life forms.
Several of the creatures were emerging from the dust mounds within twenty or thirty yards of Cunningham’s hiding place, giving rise to the hope that they would come near enough for a close ex­amination. At that distance, they were more crablike than ever, with round, flat bodies twelve to eighteen inches across, and several pairs of legs. They scuttled rapidly about, stopping at first one of the lichenous plants and then another, apparently taking a few tentative nibbles from each, as though they had delicate tastes which needed pampering. Once or twice there were fights when the same tidbit attracted the attention of more than one claim­ant; but little apparent damage was done on either side, and the victor spent no more time on the meal he won than on that which came un­contested.
Cunningham became deeply ab­sorbed in watching the antics of the little creatures, and completely for­got for a time his own rather pre­carious situation. He was recalled to it by the sound of Malmeson’s voice in his headphones.
"Don’t look up, you fool; the shields will save your skin, but not your eyes. Get under the shadow of the hull, and we’ll look over the damage."
Cunningham instantly transferred his attention to the ship. The air lock on the side toward him—the port—was open, and the bulky fig­ures of his two ex-assistants were visible standing on the ground be­neath it. They were clad in the heavy utility suits which Cunning­ham had regretted leaving, and appeared to be suffering little or no inconvenience from the heat, though they were still standing full in De­neb’s light when he looked. He knew that hard radiation burns would not appear for some time, but he held little hope of Deneb’s more deadly output coming to his assistance: for the suits were sup­posed to afford protection against this danger as well. Between heat insulation, cooling equipment, ra­diation shielding, and plain mechan­ical armor, the garments were so heavy and bulky as to be an almost insufferable burden on any major planet. They were more often used in performing exterior repairs in space.
Cunningham watched and lis­tened carefully as the men stooped under the lower curve of the hull to make an inspection of the dam­age. It seemed, from their con­versation, to consist of a dent about three yards long and half as wide, about which nothing could be done, and a series of radially arranged cracks in the metal around it. These represented a definite threat to the solidity of the ship, and would have to be welded along their full lengths before it would be safe to apply the stresses incident to second-order flight. Malmeson was too good an engineer not to realize this fact, and Cunningham heard him lay plans for bringing power lines out­side for the welder and jacking up the hull to permit access to the lower portions of the cracks. The latter operation was carried out im­mediately, with an efficiency which did not in the least surprise the hid­den watcher. After all, he had hired the men.

Every few minutes, to Cunningham’s annoyance, one of the men would carefully examine the land­scape; first on the side on which he was working, and then walking around the ship to repeat the performance. Even in the low gravity, Cunningham knew he could not cross the half mile that lay between him and that inviting air lock, be­tween two of those examinations; and even if he could, his leaping figure, clad in the gleaming metal suit, would be sure to catch even an eye not directed at it. It would not do to make the attempt unless suc­cess were certain; for his unshielded suit would heat in a minute or two to an unbearable temperature, and the only place in which it was pos­sible either to remove or cool it was on board the ship. He finally decided, to his annoyance, that the watch would not slacken so long as the air lock of the ship remained open. It would be necessary to find some means to distract or—an unpleasant alternative for a civi­lized man—disable the opposition while Cunningham got aboard, locked the others out, and located a weapon or other factor which would put him in a position to give them orders. At that, he reflected, a weapon would scarcely be neces­sary; there was a perfectly good medium transmitter on board, if the men had not destroyed or dis­charged it, and he need merely call for help and keep the men outside until it arrived.
This, of course, presupposed some solution to the problem of getting aboard unaccompanied. He would, he decided, have to examine the ship more closely after sunset. He knew the vessel as well as his own home—he had spent more time on her than in any other home— and knew that there was no means of entry except through the two main locks forward of the control room, and the two smaller, emer­gency locks near the stern, one of which he had employed on his de­parture. All these could be clogged shut from within; and offhand he was unable to conceive a plan for forcing any of the normal entrances. The view ports were too small to admit a man in a spacesuit, even if the panes could be broken; and there was literally no other way into the ship so long as the hull re­mained intact. Malmeson would not have talked so glibly of welding them sufficiently well to stand flight, if any of the cracks incurred on the landing had been big enough to admit a human body—or even that of a respectably healthy garter snake.
Cunningham gave a mental shrug of the shoulders as these thoughts crossed his mind, and reiterated his decision to take a scouting sortie after dark. For the rest of the day he divided his attention between the working men and the equally busy life forms that scuttled here and there in front of his cave; and he would have been the first to ad­mit that he found the latter more in­teresting.
He still hoped that one would ap­proach the cave closely enough to permit a really good examination, but for a long time he remained unsatisfied. Once, one of the crea­tures came within a dozen yards and stood "on tiptoe"—rising more than a foot from the ground on its slender legs, while a pair of antennae terminating in knobs the size of human eyeballs extended themselves several inches from the black carapace and waved slowly in all directions. Cunningham thought that the knobs probably did serve as eyes, though from his distance he could see only a featureless black sphere. The antennae eventually waved in his direction, and after a few seconds spent, apparently in assimilating the presence of the cave mouth, the creature settled back to its former low-swung carriage and scuttled away. Cunningham wondered if it had been frightened at his presence; but he felt reasonably sure that no eye adapted to Denebian daylight could see past the darkness of his threshold, and he had remained motionless while the creature was conducting its inspec­tion. More probably it had some reason to fear caves, or merely darkness.
That it had reason to fear some­thing was shown when another creature, also of crustacean aspect but considerably larger than those Cunningham had seen to date, appeared from among the dunes and attacked one of the latter. The fight took place too far from the cave for Cunningham to make out many details, but the larger animal quickly overcame its victim. It then apparently dismembered the vanquished, and either devoured the softer flesh inside the black in­tegument or sucked the body fluids from it. Then the carnivore dis­appeared again, presumably in search of new victims. It had scarcely gone when another being, designed along the lines of a centi­pede and fully forty feet in length, appeared on the scene with the graceful flowing motion of its ter­restrial counterpart.

For a few moments the new­comer nosed around the remains of the carnivore’s feast, and devoured the larger fragments. Then it ap­peared to look around as though for more, evidently saw the cave, and came rippling toward it, to Cun­ningham’s pardonable alarm. He was totally unarmed, and while the centipede had just showed itself not to be above eating carrion, it looked quite able to kill its own food if necessary. It stopped, as the other investigator had, a dozen yards from the cave mouth; and like the other, elevated itself as though to get a better look. The baseball-sized black "eyes" seemed for sev­eral seconds to stare into Cunning-ham’s more orthodox optics; then, like its predecessor, and to the man’s intense relief, it doubled back along its own length and glided out of sight. Cunningham again wondered whether it had de­tected his presence, or whether caves or darkness in general spelled danger to these odd life forms.
It suddenly occurred to him that, if the latter were not the case, there might be some traces of pre­vious occupants of the cave; and he set about examining the place more closely, after a last glance which showed him the two men still at work jacking up the hull.
There was drifted dust even here, he discovered, particularly close to the walls and in the corners. The place was bright enough, owing to the light reflected from outside ob­jects, to permit a good examination—shadows on airless worlds are not so black as many people believe—and almost at once Cunningham found marks in the dust that could easily have been made by some of the creatures he had seen. There were enough of them to suggest that the cave was a well-frequented neighborhood; and it began to look as though the animals were staying away now because of the man’s presence.
Near the rear wall he found the empty integument that had once covered a four-jointed leg. It was light, and he saw that the flesh had either been eaten or decayed out, though it seemed odd to think of decay in an airless environment suf­fering such extremes of tempera­ture—though the cave was less sub­ject to this affect than the outer world. Cunningham wondered whether the leg had been carried in by its rightful owner, or as a separate item on the menu of something else. If the former, there might be more relics about.
There were. A few minutes’ ex­cavation in the deeper layers of dust produced the complete exo­skeleton of one of the smaller crab-like creatures; and Cunningham carried the remains over to the cave mouth, so as to examine them and watch the ship at the same time.
The knobs he had taken for eyes were his first concern. A close examination of their surfaces revealed nothing, so he carefully tried to detach one from its stem. It finally cracked raggedly away, and proved, as he had expected, to be hollow. There was no trace of a retina in­side, but there was no flesh in any of the other pieces of shell, so that proved nothing. As a sudden thought struck him, Cunningham held the front part of the delicate black bit of shell in front of his eyes; and sure enough, when he looked in the direction of the brightly gleaming hull of the space­ship, a spark of light showed through an almost microscopic hole. The sphere was an eye, constructed on the pinhole principle—quite an adequate design on a world fur­nished with such an overwhelming luminary. It would be useless at night, of course, but so would most other visual organs here; and Cun­ningham was once again faced with the problem of how any of the crea­tures had detected his presence in the cave—his original belief, that no eye adjusted to meet Deneb’s glare could look into its relatively total darkness, seemed to be sound.
He pondered the question, as he examined the rest of the skeleton in a half-hearted fashion. Sight seemed to be out, as a result of his examination; smell and hearing were ruled out by the lack of at­mosphere; taste and touch could not even be considered under the cir­cumstances. He hated to fall back on such a time-honored refuge for ignorance as "extrasensory percep­tion", but he was unable to see any way around it.

It may seem unbelievable that a man in the position Laird Cunningham occupied could let his mind become so utterly absorbed in a problem unconnected with his per­sonal survival. Such individuals do exist, however; most people know someone who has shown some trace of such a trait; and Cunningham was a well-developed example. He had a single-track mind, and had intentionally shelved his personal problem for the moment.
His musings were interrupted, be­fore he finished dissecting his speci­men, by the appearance of one of the carnivorous creatures at what appeared to constitute a marked dis­tance—a dozen yards from his cave mouth, where it rose up on the ends of its thin legs and goggled around at the landscape. Cunningham, half in humor and half in honest curiosity, tossed one of the dis­membered legs from the skeleton in his hands at the creature. It obviously saw the flying limb; but it made no effort to pursue or de­vour it. Instead, it turned its eyes in Cunningham’s direction, and pro­ceeded with great baste to put one of the drifts between it and what it evidently considered a dangerous neighborhood.
It seemed to have no memory to speak of, however; for a minute or two later Cunningham saw it creep into view again, stalking one of the smaller creatures which still swarmed everywhere, nibbling at the plants. He was able to get a better view of the fight and the feast that followed than on the pre­vious occasion, for they took place much nearer to his position; but this time there was a rather differ­ent ending. The giant centipede, or another of its kind, appeared on the scene while the carnivore was still at its meal, and came flowing at a truly surprising rate over the dunes to fall on victor and van­quished alike. The former had no inkling of its approach until much too late; and both black bodies dis­appeared into the maw of the crea­ture Cunningham had hoped was merely a scavenger.
What made the whole episode of interest to the man was the fact that in its charge, the centipede loped unheeding almost directly through a group of the plant-eaters; and these, by common consent, broke and ran at top speed directly toward the cave. At first he thought they would swerve aside when they saw what lay ahead; but evidently he was the lesser of two evils, for they scuttled past and even over him as he lay in the cave mouth, and began to bury themselves in the deepest dust they could find. Cunningham watched with pleasure, as an excellent group of specimens thus collected themselves for his convenience.
As the last of them disappeared under the dust, he turned back to the scene outside. The centipede was just finishing its meal. This time, instead of immediately wan­dering out of sight, it oozed quickly to the top of one of the larger dunes, in full sight of the cave, and deposited its length in the form of a watch spring, with the head rest­ing above the coils. Cunningham realized that it was able, in this position, to look in nearly all direc­tions and, owing to the height of its position, to a considerable dis­tance.
With the centipede apparently settled for a time, and the men still working in full view, Cunningham determined to inspect one of his specimens. Going to the nearest wall, he bent down and groped cau­tiously in the dust. He encountered a subject almost at once, and dragged a squirming black crab into the light. He found that if he held it upside down on one hand, none of its legs could get a purchase on any­thing; and he was able to examine the underparts in detail in spite of the wildly thrashing limbs. The jaws, now opening and closing futilely on a vacuum, were equipped with a set of crushers that sug­gested curious things about the plants on which it fed; they looked capable of flattening the metal fin­ger of Cunningham’s spacesuit, and he kept his hand well out of their reach.
He became curious as to the in­ternal mechanism that permitted it to exist without air, and was faced with the problem of killing the thing without doing it too much mechani­cal damage. It was obviously able to survive a good many hours with­out the direct radiation of Deneb, which was the most obvious source of energy, although its body tem­perature was high enough to be causing the man some discomfort through the glove of his suit; so "drowning" in darkness was im­practical. There might, however, he some part of its body on which a blow would either stun or kill it ; and he looked around for a suitable weapon.

There were several deep cracks in the stone at the cave mouth, caused presumably by thermal ex­pansion and contraction; and with a little effort he was able to break loose a pointed, fairly heavy frag­ment. With this in his right hand, he laid the creature on its back on the ground, and hoped it had some­thing corresponding to a solar plexus.
It was too quick for him. The legs, which had been unable to reach his hand when it was in the center of the creature’s carapace, proved supple enough to get a purchase on the ground; and before he could strike, it was right side up and de­parting with a haste that put to shame its previous efforts to escape from the centipede.
Cunningham shrugged, and dug out another specimen. This time he held it in his hand while he drove the point of his rock against its plastron. There was no apparent effect; he had not dared to strike too hard, for fear of crushing the shell. He struck several more times, with identical results and in­creasing impatience; and at last there occurred the result he had feared. The black armor gave way, and the point penetrated deeply enough to insure the damage of most of the interior organs. The legs gave a final twitch or two, and ceased moving, and Cunningham gave an exclamation of annoyance.
On hope, he removed the broken bits of shell, for a moment looked in surprise at the liquid which seemed to have filled the body cavi­ties. It was silvery, even metallic in color; it might have been mer­cury, except that it wet the organs bathed in it and was probably at a temperature above the boiling point of that metal. Cunningham had just grasped this fact when he was violently bowled over, and the dead creature snatched from his grasp. He made a complete somer­sault, bringing up against the rear wall of the cave; and as he came up­right he saw to his horror that the assailant was none other than the giant centipede.
It was disposing with great thor­oughness of his specimen, leaving at last only a few fragments of shell that had formed the extreme tips of the legs; and as the last of these fell to the ground, it raised the fore part of its body from the ground, as the man had seen it do before, and turned the invisible pin­points of its pupils on the space-suited human figure.
Cunningham drew a deep breath, and took a firm hold of his pointed rock, though he had little hope of overcoming the creature. The jaws he had just seen at work had seemed even more efficient than those of the plant-eater, and they were large enough to take in a human leg.
For perhaps five seconds both beings faced each other without mo­tion; then, to the man’s inexpress­ible relief, the centipede reached the same conclusion to which its pre­vious examination of humanity had led it, and departed in evident haste. This time it did not remain in sight, but was still moving rapidly when it reached the limit of Cunningham’s vision.

The naturalist returned some­what shakily to the cave mouth, seated himself where he could watch his ship, and began to ponder deeply. A number of points seemed interesting on first thought, and on further cerebration became positively fascinating. The centi­pede had not seen, or at least had not pursued, the plant-eater that had escaped from Cunningham and run from the cave. Looking back, he realized that the only times he had seen the creature attack was after "blood" had been already shed —twice by one of the carnivorous animals, the third time by Cunning­ham himself. It had apparently made no difference where the vic­tims had been—two in full sunlight, one in the darkness of the cave. More proof, if any were needed, that the creatures could see in both grades of illumination. It was not strictly a carrion eater, however; Cunningham remembered that car­nivore that had accompanied its vic­tim into the centipede’s jaws. It was obviously capable of overcom­ing the man, but had twice retreated precipitately when it had excellent opportunities to attack him. What was it, then, that drew the creature to scenes of combat and bloodshed, but frightened it away from a man; that frightened, indeed, all of these creatures?
On any planet that had a respect­able atmosphere, Cunningham would have taken one answer for granted—scent. In his mind, how­ever, organs of smell were associ­ated with breathing apparatus. which these creatures obviously lacked.
Don’t ask why he took so long. You may think that the terrific adaptability evidenced by those strange eyes would be clue enough: or perhaps you may be in a mood to excuse him. Columbus prob­ably excused those of his friends who failed to solve the egg prob­lem.
Of course, he got it at last, and was properly annoyed with himself for taking so long about it. An eye, to us, is an organ for forming images of the source of such radia­tion as may fall on it; and a nose is a gadget that tells its owner of the presence of molecules. He needs his imagination to picture the source of the latter. But what would you call an organ that forms a picture of the source of smell?
For that was just what those "eyes" did. In the nearly perfect vacuum of this little world’s surface, gases diffused at high speed—and their molecules traveled in practically straight lines. There was nothing wrong with the idea of a pinhole camera eye, whose retina was composed of olfactory nerve endings rather than the rods and cones of photosensitive organs.
That seemed to account for everything. Of course the crea­tures were indifferent to the amount of light reflected from the object they examined. The glare of the open spaces under Deneb’s rays, and the relative blackness of a cave, were all one to them—provided something were diffusing molecules in the neighborhood. And what doesn’t? Every substance, solid or liquid, has its vapor pressure; under Deneb’s rays even some rather un­likely materials probably evaporated enough to affect the organs of these life forms—metals, particularly. The life fluid of the creatures was obviously metal—probably lead, tin, bismuth, or some similar metals, or still more probably, several of them in a mixture that carried the sub­stances vital to the life of their body cells. Probably much of the make­up of those cells was in the form of colloidal metals.
But that was the business of the biochemists. Cunningham amused himself for a time by imagining the analogy between smell and color which must exist here; light gases, such as oxygen and nitrogen, must be rare, and the tiny quantities that leaked from his suit would be ab­solutely new to the creatures that intercepted them. He must have af­fected their nervous systems the way fire did those of terrestrial wild animals. No wonder even the cen­tipede had thought discretion the better part of valor!

With his less essential problem solved for the nonce, Cunningham turned his attention to that of his own survival; and he had not pon­dered many moments when he real­ized that this, as well, might be solved. He began slowly to smile, as the discrete fragments of an idea began to sort themselves out and fit properly together in his mind—an idea that involved the vapor pres­sure of metallic blood, the leaking qualities of the utility suits worn by his erstwhile assistants, and the bloodthirstiness of his many-legged acquaintances of the day; and he had few doubts about any of those qualities. The plan became com­plete, to his satisfaction; and with a smile on his face, he settled him­self to watch until sunset.
Deneb had already crossed a con­siderable arc of the sky. Cunning­ham did not know just how long he had, as he lacked a watch; and it was soon borne in on him that time passes much more slowly when there is nothing to occupy it. As the afternoon drew on, he was forced away from the cave mouth; for the descending star was beginning to shine in. Just before sunset, he was crowded against one side; for Deneb’s fierce rays shone straight through the entrance and onto the opposite wall, leaving very little space not directly illuminated. Cun­ningham drew a sigh of relief for more reasons than one when the upper limb of the deadly luminary finally disappeared.
His specimens had long since recovered from their fright, and left the cavern; he had not tried to stop them. Now, however, he emerged from the low entryway and went directly to the nearest dust dune, which was barely visible in the star­light. A few moment’s search was rewarded with one of the squirming plant-eaters, which he carried back into the shelter; then, illuminating the scene carefully with the small torch that was clipped to the waist of his suit, he made a fair-sized pile of dust, gouged a long groove in the top with his toe, with the aid of the same stone he had used be­fore, he killed the plant-eater and poured its "blood" into the dust mold.
The fluid was metallic, all right; it cooled quickly, and in two or three minutes Cunningham had a silvery rod about as thick as a pencil and five or six inches long. He had been a little worried about the centipede at first; but the creature was either not in line to "see" into the cave, or had dug in for the night like its victims.
Cunningham took the rod, which was about as pliable as a strip of solder of the same dimensions, and, extinguishing the torch, made his way in a series of short, careful leaps to the stranded spaceship. There was no sign of the men, and they had taken their welding equipment inside with them—that is, if they had ever had it out; Cunning­ham had not been able to watch them for the last hour of daylight. The hull was still jacked up, how­ever; and the naturalist eased him­self under it and began to examine the damage, once more using the torch. It was about as he had de­duced from the conversation of the men; and with a smile, he took the little metal stick and went to work. He was busy for some time under the hull, and once he emerged, found another plant-eater, and went back underneath. After he had fin­ished, he walked once around the ship, checking each of the air locks and finding them sealed, as he had expected.
He showed neither surprise nor disappointment at this; and with­out further ceremony he made his way back to the cave, which he had a little trouble finding in the star­light. He made a large pile of the dust, for insulation rather than bed­ding, lay down on it, and tried to sleep. He had very little success, as he might have expected.
Night, in consequence, seemed unbearably long; and he almost re­gretted his star study of the pre­vious darkness, for now he was able to see that sunrise was still distant, rather than bolster his morale with the hope that Deneb would be in the sky the next time he opened his eyes. The time finally came, how­ever, when the hilltops across the valley leaped one by one into bril­liance as the sunlight caught them; and Cunningham rose and stretched himself. He was stiff and cramped, for a spacesuit makes a poor sleep­ing costume even on a better bed than a stone floor.
As the light reached the spaceship and turned it into a blazing silvery spindle, the air lock opened. Cun­ningham had been sure that the men were in a hurry to finish their task, and were probably awaiting the sun almost as eagerly as he in order to work efficiently; he had planned on this basis.

Malmeson was the first to leap to the ground, judging by their conversation, which came clearly through Cunningham’s phones. He turned back, and his companion handed down to him the bulky di­ode welder and a stack of filler rods. Then both men made their way for­ward to the dent where they were to work. Apparently they failed to notice the bits of loose metal ly­ing on the scene—perhaps they had done some filing themselves the day before. At any rate, there was no mention of it as Malmeson lay down and slid under the hull, and the other began handing equipment in to him.
Plant-eaters were beginning to struggle out of their dust beds as the connections were completed, and the torch started to flame. Cun­ningham nodded in pleasure as he noted this; things could scarcely have been timed better had the men been consciously co-operating. He actually emerged from the cave, keeping in the shadow of the hil­lock, to increase his field of view; but for several minutes nothing but plant-eaters could be seen moving.
He was beginning to fear that his invited guests were too distant to receive their call, when his eye caught a glimpse of a long, black body slipping silently over the dunes toward the ship. He smiled in sat­isfaction; and then his eyebrows suddenly rose as he saw a second snaky form following the tracks of the first.
He looked quickly across his full field of view, and was rewarded by the sight of four more of the mon­sters—all heading at breakneck speed straight for the spaceship. The beacon he had lighted had reached more eyes than he had ex­pected. He was sure that the men were armed, and had never intended that they actually be overcome by the creatures; he had counted on a temporary distraction that would let him reach the air lock unop­posed.
He stood up, and braced himself for the dash, as Malmeson’s helper saw the first of the charging centi­pedes and called the welder from his work. Malmeson barely had time to gain his feet when the first pair of attackers reached them; and at the same instant Cunningham emerged into the sunlight, putting every ounce of his strength into the leaps that were carrying him to­ward the only shelter that now existed for him.
He could feel the ardor of De­neb’s rays the instant they struck him; and before he had covered a third of the distance the back of his suit was painfully hot. Things were hot for his ex-crew as well; fully ten of the black monsters had reacted to the burst of—to them—overpoweringly attractive odor—or gorgeous color?—that had resulted when Malmeson had turned his welder on the metal where Cun­ningham had applied the frozen blood of their natural prey; and more of the same substance was now vaporizing under Deneb’s in­fluence as Malmeson, who had been lying in fragments of it stood fight­ing off the attackers. He had a flame pistol, but it was slow to take effect on creatures whose very blood was molten metal; and his companion, wielding the diode unit on those who got too close, was no better off. They were practically swamped under wriggling bodies as they worked their way toward the air lock; and neither man saw Cun­ningham as, staggering even under the feeble gravity that was present, and fumbling with eye shield misted with sweat, he reached the same goal and disappeared within.
Being a humane person, he left the outer door open; but he closed and clogged the inner one before proceeding with a more even step to the control room. Here he un­hurriedly removed his spacesuit, stopping only to open the switch of the power socket that was feeding the diode unit as he heard the outer lock door close. The flame pistol would make no impression on the alloy of the hull, and he felt no qualms about the security of the inner door. The men were safe, from every point of view.
With the welder removed from the list of active menaces, he fin­ished removing his suit, turned to the medium transmitter, and coolly broadcast a call for help and his position in space. Then he turned on a radio transmitter, so that the rescuers could find him on the planet; and only then did he contact the prisoners on the small set that was tuned to the suit radios, and tell them what he had done.
"I didn’t mean to do you any harm," Malmeson’s voice came back. "I just wanted the ship. I know you paid us pretty good, but when I thought of the money that could be made on some of those worlds if we looked for something besides crazy animals and plants, I couldn’t help myself. You can let us out now; I swear we won’t try anything more—the ship won’t fly, and you say a Guard flyer is on the way. How about that?"
"I’m sorry you don’t like my hobby," said Cunningham. "I find it entertaining; and there have been times when it was even useful, though I won’t hurt your feelings by telling you about the last one. I think I shall feel happier if the two of you stay right there in the air lock; the rescue ship should be here before many hours, and you’re fools if you haven’t food and water in your suits."
"I guess you win, in that case," said Malmeson.
"I think so, too," replied Cun­ningham, and switched off.


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[1Hal Clement was the pen name of Harry Clement Stubbs.