1

Sallman Ken had never been really sure of the wisdom he had shown in acceding to Rade’s request. He was no policeman and knew it. He had no particular liking for physical danger. He had always believed, of course, that he could stand his share of discomfort, but the view he was now getting through the Karella’s port was making him doubt even that.

Rade had been fair enough, he had to admit. The narcotics chief had told him, apparently, everything he himself knew; enough so that Ken, had he used his imagination sufficiently, might even have foreseen something like this.

“There has never been much of it,” Rade had said. “We don’t even know what the peddlers call it — it’s just a ‘sniff’ to them. It’s been around for quite a few years now; we got interested when it first appeared, and then took most of our attention from it when it never seemed to amount to much.”

“But what’s so dangerous about it, then?” Ken had asked.

“Well, of course any habit-forming drug is dangerous — you could hardly be a teacher of science without knowing that. The special menace of this stuff seems to lie in the fact that it is a gas, and can therefore be administered easily without the victim’s consent; and it seems to be so potent that a single dose will insure addiction. You can see what a public danger that could be.” Ken had seen, clearly.

“I should say so. I’m surprised we haven’t all been overcome already. A generator in a building’s ventilation system — on board a ship — anything like that could make hundreds of customers for whoever has the stuff to sell. Why hasn’t it spread?” Rade had smiled for the first time.

“There seems to be two reasons for that, also. There are production difficulties, if the very vague stories we hear have anything in them; and the stuff doesn’t keep at normal temperature. It has to be held under extreme refrigeration; when exposed to normal conditions it breaks down in a few seconds. I believe that the active principle is actually one of the breakdown products, but no one had obtained a sample to prove it.”

“But where do I come in? If you don’t have any of it I can’t analyze it for you. I probably couldn’t anyway — I’m a school teacher, not a professional chemist. What else can I do?”

“It’s because you’re a teacher — a sort of jack-of-all-trades in scientific matters, without being an expert at any of them — that we think you can help us. I mentioned that there seemed to be production troubles with the drug.

“Certainly the producers would like to increase volume. They would like, of course, to get a first-rate production engineer. You know as well as I that they could never do it; no such person could be involved secretly in such a matter. Every competent engineer is well employed since Velio was discovered, and it would be too easy for us to trace one who was approached for such a purpose.

“You, however, are a comparatively inconspicuous person; you are on vacation, and will be for another year; no one will miss you — we expect these people to think. That’s why we took such extreme precautions in arranging this interview.”

“But you’ll have to publicize me some way, or they would never know I existed, either,” Ken pointed out.

“That can be done — in fact, has already started. I trust you’ll forgive us for that; but the job is important. The whisper has already started in criminal circles that you are the manufacturer of the bomb that wrecked the Storm plant. We can give you quite a reputation—”

“Which will prevent my ever getting an honest job again.”

“Which will never be heard of by your present employers, or by any respectable person not associated with the police.”

Ken was not yet sure why he had accepted. Maybe the occupation of policeman still carried a little subconscious glamour, though certainly it was now mostly laboratory work. This looked like an exception — or did it? He had as Rade expected been hired by an extremely short-spoken individual, who claimed to represent a trading concern. The understanding had been that his knowledge was to be placed at the disposal of his employers. Perhaps they would simply stick him in a lab with the outline or a production problem, and tell him to solve it. In that case, he would be out of a job very quickly, and if he were lucky might be able to offer his apologies to Rade.

For he certainly had learned nothing so far. Even the narcotics man had admitted that his people knew no one at all certainly connected with the ring, and it was very possible that he might be hired by comparatively respectable people — compared, of course, to drug-runners. For all Ken could tell at the moment, that might have happened. He had been shepherded aboard the Karella at the North Island spaceport, and for twenty-two days had seen nothing at all.

He knew, of course, that the drug came from off the planet. Rade had become sufficiently specific to admit that the original rush had been checked by examining incoming refrigeration apparatus. He did not know, however, that it came from outside the Sarrian planetary system. Twenty-two days was a long journey — if it had been made in a straight line.

Certainly the world that hung now beyond the port did not look as though it could produce anything. Only a thin crescent of it was visible, for it lay nearly between the ship and a remarkably feeble sun. The dark remainder of the sphere blotted out the Milky Way in a fashion that showed the planet to be airless. It was mountainous, inhospitable, and cold. Ken knew that last fact because of the appearance of the sun. It was dim enough to view directly without protection to the eyes; to Ken’s color sense, reddish in shade and shrunken in aspect. No world this far from such a star could be anything but cold.

Of course, Rade’s drug needed low temperature — well, if it were made here, Ken was going to resign, regardless. Merely looking at the planet made him shiver.

He wished someone would tell him what was going on. There was a speaker over the door of his room, but so far the only times it had been used was to tell him that there was food outside his room and the door was unlocked for the moment.

For he had not been allowed to leave his room. That suggested illegal proceedings of some sort; unfortunately it did not limit them to the sort he was seeking. With the trading regulations what they were, a mercantile explorer who found an inhabited system more often than not kept the find strictly for his own exploitation. The precaution of concealing its whereabouts from a new employee was natural.

At a venture, he spoke aloud. After all, the fact that they were hanging so long beside this world must mean something.

“Is this where I’m expected to work? You’ll pardon my saying that it looks extremely unpleasant.” A little to his surprise there was an answer, in a voice different from the one that had announced his meals.

“I agree. I have never landed there myself, but it certainly looks bad. As far as we know at present, your job will not require you to visit that world.”

“Just what is my job? Or don’t you want to tell me yet?”

“There is no harm in telling you more, anyway, since we have arrived at the proper planetary system.” Ken cast an uneasy eye at the feeble sun as he heard these words, but continued to listen without comment.

“You will find the door unlocked. Turn to your right in the corridor outside, and proceed for about forty yards — as far as you can. That will take you to the control room, where I am. It will be more comfortable to talk face to face.” The speaker’s rumble ceased, and Ken did as he was told. The Karella seemed to be a fairly common type of interstellar flyer, somewhere between one hundred fifty and two hundred feet in length, and about one third that diameter. It would be shaped like a cylinder with slightly rounded ends. Plenty of bulk — usable for passengers, cargo, or anything else her owner cared.

The control room contained nothing worthy of comment, except its occupants. One of these was obviously the pilot; he was strapped to his rack in front of the main control panel. The other was floating free in the middle of the room, obviously awaiting Ken’s arrival since he had both eyes on the door. He spoke at once, in a voice recognizable as the one which had invited the scientist forward.

“I was a little hesitant about letting you see any of us personally before having your final acceptance of our offer; but I don’t see that it can do much harm, after all. I scarcely ever visit Sarr nowadays, and the chance of your encountering me if we fail to reach a final agreement is small.”

“Then you are engaged in something illegal?” Ken felt that there could be little harm in mentioning a fact the other’s speech had made so obvious. After all, they would not expect him to be stupid.

“Illegal, yes, if the law be interpreted — strictly. I feel, however, and many agree with me, that if someone finds an inhabited planet, investigates it at his own expense, and opens relations with the inhabitants, that he has a moral right to profit from the fact. That, bluntly, is our situation.”

Ken’s heart sank. It began to look as though he had stumbled on the very sort of petty violation he had feared, and was not going to be very useful to Rade.

“There is certainly some justice in that viewpoint,” he said cautiously. “If that is the case, what can I do for you? I’m certainly no linguist, and know next to nothing of economic theory, if you’re hitting trading difficulties.”

“We are having difficulties, but not in that way. They stem from the fact that the planet in question is so different from Sarr that personal visits are impossible. We have had the greatest difficulty in establishing contact of a sort with even one group of natives — or perhaps a single individual; we can’t tell.”

“Can’t tell? Can’t you send a torpedo down with television apparatus, at least?”

“You’ll see.” The still nameless individual gave a rather unpleasant smile. “At any rate, we have managed to do a little trading with this native or natives, and found that they have something we can use. We get it, as you can well imagine, in trickles and driblets. Basically, your problem is — how do we get more of it? You can try to figure out some way of landing in person if you like, but I know you’re not an engineer. What I thought you could do was get a good enough analysis of the planet’s conditions — atmosphere, temperature, light, and so on — so that we could reproduce them in a more convenient location and grow our own product. That way, we wouldn’t be forced to pay the price the native asks, too.”

“That sounds simple enough. I notice you don’t seem to want me to know what the product is — except that it seems to be of vegetable nature — but that doesn’t bother me. I had a friend in the perfume business once, and the way he tried to keep secrets in elementary chemistry was a scandal. I’m certainly willing to try — but I warn you I’m not the Galaxy’s best chemist by a long shot, and I’ve brought no apparatus with me, since I didn’t know what you wanted me to do. Have you anything here in the ship?”

“Not in the ship. We discovered this place around twenty years ago, and have built a fairly comfortable base on the innermost planet of this system. It keeps the same hemisphere facing the sun all the time, and we’ve been able to concentrate enough sunlight in a small valley to make the temperature quite bearable. There’s a fairly respectable laboratory and shop there, with a very good mechanic named Feth Allmer; and if you find yourself in need of something we don’t have, we can probably afford to get it for you. How does that sound?”

“Very good indeed. I’ll take your job, and do what I can.” Ken was a little happier at this point, partly because the job seemed interesting in itself and partly because of some of the other’s statements. If this product was a plant, as seemed to be the case, there was at least a slight possibility that he was not on a blind run after all. The matter of the need for refrigeration, of course, had not come up specifically — for all that had been said so far, the planet was as likely to be too hot as too cold for comfort; but what he had seen of this system’s sun made that seem doubtful. Then there was the reference to warming the innermost planet — no, the place was cold. Definitely, Chances improved again. He switched his attention from these thoughts, as he realized that his employer — if this were really the head of the concern — was speaking again.

“I was sure you would. You can give orders for anything you need, starting now. You may use this ship as you please, subject only to Ordon Lee’s veto if he considers the vessel in danger.” The pilot was indicated by the wave of a supple tentacle as the name was pronounced. “Incidentally, I am Laj Drai. You are working for me, and I am sure we will both be more comfortable if that fact is borne in mind. What do you think should be done first?”

Ken decided to ignore Drai’s subtle implication of superiority, and answered the question with another.

“Do you have any samples of the atmosphere or soil of this planet?” -

“Of the first, no. We have never been able to keep a sample; probably we did not collect it properly. One cylinder that was collected leaked and burned in our air, for what that may be worth. We do have bits of soil, but they were all exposed to our own air at one time or another, and may have been changed by that. You will have to decide that for yourself. All that I really know is that their atmosphere has a pressure around two thirds of Sarr-normal, and at its base the temperature is low enough to freeze most of the regular gases out of our own air — I believe it would even freeze potassium. Our mechanic claimed that was what happened to one device that failed to work.”

“How about size?”

“Bigger than Sarr — the figures are all at the base on Planet One; it would be easier to look them over there. I don’t pretend to remember any of them at all precisely — as a matter of fact, we don’t have any of them too precisely. You’re the scientist, as far as we are concerned; my people are just eyes and tentacles for you.

“We do have remote-controlled torpedoes, as you suggested. It might be well to tell me before you use them; we lost nineteen of the first twenty to reach the planet’s surface. We planted a permanent transmitter at the point where the twentieth landed, and we always home down on it now. Just what happened to the others we don’t exactly know, though we have a pretty good guess. I’ll tell you the whole story at the same time that you look over the other material. Is there anything you’d care to do before we leave the vicinity of the planet and go over to One?”

“Leave the vicinity? I thought you said that world was not the one in question.” Ken waved a tentacle at the cratered crescent.

“That one isn’t — that’s a satellite of Three, the one we’re interested in.”

A chill came back to Ken’s skin. The satellite had been frightening; the planet itself could be little if any warmer since it must be about the same distance from the sun. An atmosphere would help a little, of course; but still — cold enough to freeze potassium, and lead, and tin! He had not given real thought to that. His imagination was good— perhaps a little too good; and it began conjuring up out of nothing in particular an image of a world chilled to the core. It was rough, and an icy blizzard played over it, and nothing moved in the dim reddish light — a planet of death.

But that couldn’t be right; there were natives. Ken tried to imagine the sort of life that could exist under such hideous conditions, and failed completely. Maybe Laj Drai was wrong about the temperature; after all, he hadn’t been sure. It was just a mechanic’s opinion.

“Let’s see this place, since we’re so close to it. I might as well learn the worst,” he said at this point in his imagining. Laj Drai gestured to the pilot, and the hull of the Karella rotated slowly. The airless satellite slid out of sight, and stars followed it across the field of view. The ship must have spun a full hundred and eighty degrees before Planet Three itself hung in the apparent center of the port. They must be floating directly between planet and satellite, Ken thought. Not wise if the inhabitants had telescopes.

Since the sun was now behind them, the disc of the great world was fully illuminated. Unlike the bare moon, a fuzziness of outline showed that it possessed an extensive atmosphere, though Ken could not imagine what gases might be present. In spite of the definitely reddish sunlight, most of the surface had a decided blue tint. Details were impossible to make out; the atmosphere was extremely hazy. There were definite patches of white, and green, and brown, but there was no way of telling what any of them represented.

And yet, foggy as it was, there was something about the sight of the world which caused the shiver to caress the scientist’s skin once more. Perhaps it was the things he had been told, and the things he had deduced from the appearance of the sun; perhaps it was nothing objective at all. Whatever it was, the very sight of the world made him shudder, and he turned away abruptly.

“Let’s go to One, and look over that data,” he said, striving to control his voice diaphragm. The pilot obeyed without comment.

Earth, really, is not as bad as all that. Some people are even quite fond of it. Ken, of course, was prejudiced, as anyone is likely to be against a world where water is a liquid — when he has grown up breathing gaseous sulfur and, at rare intervals, drinking molten copper chloride.

2

Roger Wing, for example, would probably have been slightly shocked at Ken’s attitude. He was strongly in favor of Earth, at least the rather small portion which he knew. He had some justification, for the country around Lake Pend’ Oreille is very much worth knowing, particularly in spring and summer. The first glimpse of the lake each June was something to look forward to; all the way up the highway from Hayden Lake the children maintained shrill rivalry over who would be the first to sight the Ear Drop. Even with only four of them this year, the noise was nearly as great as usual; for the absent Donald had never contributed too much to the racket. Roger, left the senior member by his older brother’s absence, was determined to make the most of the opportunity; the more so since it was to last only another forty miles or so. Don was expected to fly to Sandpoint with a friend and meet the family there.

It was, all in all, a hilarious group; and the parents in the front seat had only moderate success in maintaining order. However, the northbound highway from Coeur d’Alene is a good one, and the disturbance in the rear was never really dangerous. The principal interruption occurred when the right rear tire of the station wagon went flat near Cocolalla. John Wing was a little slow in stopping the heavily loaded vehicle, and Roger got the first whiff of the sulfurous odor of burning rubber. He was to became much more familiar with sulfur during the course of the summer.

The children were a little quieter after that — the expression on their father’s face suggested that his patience might not have much farther to go; but the journey was never really silent. The causeway across the tip of Pend’ Oreille was greeted with ringing cheers, which ceased only momentarily while Mr. Wing purchased a new tire in Sandpoint. Then they proceeded to the small airport at the edge of the town, and the noise increased again as the youngsters caught sight of their oldest brother standing beside a Cub on the grass parking area.

He was tall, and rather slim, with dark hair and eyes and a narrow face like his father’s. Roger, who had grown considerably since the last September, discovered to his chagrin that Donald still overtopped him by half a head; but he did not let the annoyance lessen the exuberance of his greeting. Don shook hands with his father and Roger, kissed his mother and sisters, and swung six-year-old Billy to his shoulder. No, the flight from Missoula had not been eventful. Yes, his final grades had been good, if not outstanding. No, he had no luggage except the little handbag beside him — a Cub has sharp load limitations. They might as well continue their journey, and he could answer questions on the way. He tossed the bag at Roger and moved toward the station wagon, Billy still on his shoulder; and with the crowd settled more or less comfortably, they rolled on.

North from Sandpoint; east fork to Kootenai; around the north end of the question-mark-shaped lake to Hope, and on to Clark Fork. There the car was left, in a building that partook of the characteristics of storehouse and garage.

Don and Roger disappeared, and returned with an imposing array of pack and saddle horses. These were accoutered with a speed which suggested the maneuver was not a new one to the family; and the Wings, waving farewell to their acquaintances who had gathered to see them off, headed northward into the woods.

Donald grinned at his father as the town vanished behind them.

“How many campers do you suppose we’ll have this year?”

“It’s hard to say. Most of the folks who know us have come to mind their own business pretty well, and I didn’t notice any strangers in the town; but prospectors seem to turn up when least expected. I don’t mind honest prospecting — it lends protective coloration. It’s the ones who expect to benefit from our ‘strike’ that bother me. You boys will have to scout as usual — though I may want Don with me this time. If you’ve really gotten something out of freshman chemistry, Son, you may be able to help solve a problem or two. If he does go with me, Roger, you’ll have a bigger responsibility than usual.” The boy nodded, eyes shining.

He had only gradually come to realize the tremendous difference between the way his family and those of his schoolmates spent their summers. At first, the tales of trips to ranches, seashores, and mountains had aroused his envy; then he had begun to boast of his own mountain trips. When he finally realized the atmosphere of secrecy that surrounded certain aspects of those trips, his pride had exceeded his powers of restraint — until he had realized that his schoolmates simply didn’t believe that his father had a “secret mine in the mountains.” Pique had silenced his boasts for a while and by the time he had developed a convincing argument he had realized that silence might be better for all concerned.

That had been the spring when he was ten years old. His father had somehow heard about the whole story, and seemed pleased for some reason; that summer he had extended to Roger the responsibility which Don had been carrying alone, of scouting the territory around their summer home before and during Mr. Wing’s trips into the mountains. The find, their father had told him, was his own secret; and for reasons he would explain later it must be kept that way.

That summer and the two following he had continued to make his trips alone; now it looked as though there might be a change. Don, Roger knew, had been told a little just before leaving for college the preceding fall; his courses had been partly selected on the basis of that information — chemistry, astronomy and mathematics. The first seemed logical, but Roger failed to see the point of the others. Certainly astronomy seemed of doubtful value in anything connected with mining.

Still, he would find that out in due course; perhaps sooner than Don had, since their father seemed to be letting down the bars. His problem for the moment was to figure out a way by which one boy could keep himself informed about every person who came within a mile of the summer house in any direction — and farther than that in some directions. Roger, of course, knew the topography of the neighborhood quite well; but he began right then planning a series of exploration jaunts to make more certain of some points. He was a young man who took things seriously, if they were presented to him in that light.

Like anyone else of his own age, however, he tended even more strongly to fly off on the interests of the moment; and he was easily aroused from his reverie when Edie caught him in the face with a fir cone slyly tossed over her shoulder. She burst into laughter as he looked around fruitlessly for a means of retaliation — there seemed to be no more cones within reach, and the trail at this point was too narrow for the horses to travel side by side. The pack horse the girl was leading formed, for the time being, an impassable barrier.

“Why don’t you wake up and join the party?” Edith finally gurgled out between spasms of laughter. “You looked as though you’d just remembered leaving your favorite fishpole in Spokane!” Roger assumed a mantle of superiority.

“Of course, you girls have nothing to do between now and September,” he said. “There’s a certain amount of men’s work to be done, though, and I was deciding how to go about it.”

“Men’s work?” The girl raised her eyebrows in mock surprise. “I know Dad will be busy, but what’s that to you?” She knew perfectly well what Roger’s summer duties were, but had reasons of her own for speaking as she did. “Does it take a man to stroll around the house on sentry-go a couple of times a day?” Roger stiffened.

“It takes more than a girl to do a good job of it,” he retorted. The words were hardly out when he regretted them; but he had no time to think of a way out of the corner into which he had talked himself.

“Evidence!” Edith responded quietly, and Roger mentally kicked himself. She had been playing for just that. Family rules required that any statement made by a member of the family be backed up with evidence if another member required it — a rule the elder Wing had instituted, with considerable foresight. He was seldom caught by it himself, being a thoughtful man by nature.

“You’ll have to let me try, now,” Edith remarked, “and you’ll have to give me a fair amount of teaching. To be really fair, you’ll have to let Margie try, too—” The last was an afterthought, uttered principally for its explosive effect. Roger almost left his saddle, but before he succeeded in expressing himself a thought struck him. After all, why couldn’t the girls help? He could show them what he and Don had done in the past, and they might very well have ideas of their own. Roger’s masculine pride did not blind him to the fact that girls in general, and his sisters in particular, did have brains. Edie and Marge could both ride, neither was afraid of the woods, and all things considered would probably make extremely useful assistants. Edith was so near to his own age that he could not dismiss her as too young for the work, and even the eight-year-old had at least sense enough to keep quiet when silence was needed and obey orders when argument would be injudicious.

“All right. You can both try it.” Roger brought his cogitation to an end. “Dad won’t mind, I guess, and Mother won’t care if the work gets done. We’ll have a conference tonight.”

The conversation shifted to other matters, and the caravan wound on up the river. Two or three hours out of Clark Fork they crossed the stream and headed eastward toward the Montana border; and there were still several hours of daylight remaining when they reached the “summer cottage.”

It was hardly a cottage. Built well up on a steep hillside, though still below the timber line, it boasted enough rooms to house the Wing family without any fear whatever of crowding. It possessed a gasoline-powered electric plant, a more or less limited supply of running water piped from a spring farther up the hill, and in general bore witness to Mr. Wing’s luck or skill in the prospecting which was supposed to be the source of his income.

A short distance downhill from the dwelling was another building which combined the functions of storehouse and stable. Both structures were solidly built, and had never suffered serious damage from the Northwest winters. The foundation of the house was part of the bedrock core of the mountain, and its walls were well insulated. The family could easily have lived there the year round, and the parents had vague plans of doing so once the children had all finished school.

The first floor consisted of a big room which did duty as dining room and parlor, with a kitchen at one end and bedroom at the other. An open stair well by the kitchen door went down to a basement, containing work benches cluttered with woodworking and radio paraphernalia as well as the wherewithal for various games. The stair to the second floor was at the other end; this was divided into six much smaller rooms, one serving as bedroom for each of the children and the remaining one filled with the various odd articles of furniture and bric-a-brac which are apt to find their way into a spare room over a period of years.

The Wings dismounted by the porch which ran along the front of the dwelling, and promptly dispersed to their various duties. Mrs. Wing and the girls unlocked the front door and disappeared inside. Billy began unscrewing and removing the shutters on the more accessible windows — those along the porch, and the first-floor ones on the uphill side of the dwelling. Mr. Wing and Donald began unloading the pack animals, while Roger took the other horses down to the stable, unsaddled, and fed them.

By sunset, the house had assumed an inhabited air. Everyone had eaten, dishes had been washed, Billy and Marjorie were in bed, and the remaining members of the family had settled down for a few minutes of relaxation in the main room. There had been some debate as to whether the fireplace should be used, which had been won by the affirmatives — not so much because of the temperature, though even a June night can be chilly in the Cabinets, but simply because they liked to sit around a fire.

The parents were ensconced in their respective seats on each side of the stone fireplace. Donald, Roger and Edith sprawled on rugs between; Roger had just put forth the suggestion that the girls help in the scouting job. His father thought for a minute or two.

“Do you know your way around well enough, in directions other than toward town?” he finally asked Edith.

“Not as well as the boys, I suppose, but they had to Learn sometime or other,” she countered.

“True enough. I wouldn’t want you to turn up missing, and your mother can’t be expected to do all the housework herself. Well, Roger seems to have let himself in for proving a point, so let’s put it this way. It will be a week or ten days before I go out for the first time. In that time the two of you, working together, will turn in a satisfactory map of the territory within three miles of this house, and a patrol schedule that will permit Edie’s housework to be done at times satisfactory to your mother. Margie may go with you, but is not to go beyond the half-mile marks alone — the old rules hold for the younger people, still. That is subject to any additions or alterations your mother may see fit to make.” He looked across at his wife, with a half smile on his face. She returned the smile, and nodded.

“That seems all right. Roger has a few duties of his own, I believe; hadn’t they better be included in the last item?”

“Fair enough. Does that suit you, Rog? Edie? all right,” as the two nodded, “time for bed. You seem to have the time for the next few days pretty well filled.” The two youngsters grimaced but obeyed; Don and his parents remained. They talked seriously in low tones far into the night. The four younger children had been asleep for several hours when Donald finally climbed the stairs to his room, but the fact did not lessen his caution. He had no desire to spend the rest of the night ducking Roger’s questions about what had gone on downstairs.

In spite of the rather strenuous day just finished, the entire family was up early the next morning. As a “special favor” to his younger brother, Donald volunteered to take the surplus horses back to town — they kept only a few at the summer house, as fodder was a little difficult to obtain. That left the younger boy free, once the shutters were removed from the upstairs windows, to get out on the mapping job, as far as his own work was concerned. Edith was delayed for a while dusting off china and washing cooking utensils — they had cleaned only enough for a sketchy meal the night before — but Roger conquered any slight distaste he might have had for women’s work and helped out. The sun was not yet very high when they emerged onto the porch, consulted briefly, and started uphill around the house.

The boy carried a small Scout compass and a steel tape which had turned up in the basement workshop; his sister had a paper-covered notebook, a school relic still possessed of a few blank pages. Between his father’s teaching and a year in a Scout troop, Roger was sure he could produce a readable map of the stipulated area with no further equipment. He had not considered at all carefully the problem of contours.

High as the Wing house was located, there was still a long climb above it; and both youngsters were quite willing to rest by the time they reached the top. They were willing, too, to sit and look at the view around them, though neither was a stranger to it.

The peaks of the Cabinets extended in all directions except the West. The elevation on which they were located was not high enough to permit them to see very far; but bits of Pend’ Oreille were visible to the southwest and the easily recognized tip of Snowshoe Peak rose between east and south. Strictly speaking, there was no definite timber line; but most of the peaks managed to thrust bare rock through the soil for at least a few hundred feet. The lower slopes were covered with forest, principally the Douglas fir which is so prevalent in the Pacific Northwest. One or two relatively clear areas, relics of forest fires of the last few years, were visible from the children’s point of vantage.

There were a number of points visible within the distance specified by Mr. Wing which looked as though they might serve as reference stations, and presently Roger took out the compass and began taking bearings on as many of these as he could. Edith was already making a free-hand sketch map of their surroundings, and the bearings were entered on this. Distances would come later; Roger knew neither his own altitude nor those of the points he was measuring, and could not have used the information had he possessed it. He knew no trigonometry and had no means of measuring angles of depression.

Details began to crowd the rough chart even before they left the hilltop; and presently the two were completely absorbed in their task. Mrs. Wing was not particularly surprised when they came in late for dinner.

3

The station on Planet One was a decidedly primitive installation, though a good deal of engineering had obviously been needed to make it habitable at all. It was located in the bottom of a deep valley near the center of the planet’s sunward hemisphere, where the temperature was normally around four hundred degrees Centigrade. This would still have been cold enough to liquefy the sulfur which formed the principal constituent of the atmosphere Ken’s people needed; but the additional hundred degrees had been obtained by terracing the valley walls, cutting the faces of the terraces to the appropriate slope, and plating them with iron. The dark-colored metal dome of the station was, in effect, at the focus of a gigantic concave mirror; and between the angular size of sun and the actual size of the dome, solar libration never moved the focus to a serious extent.

The interstellar flyer settled onto a smooth sheet of bare rock beside the dome. There were no cradling facilities, and Ken had to don vacuum armor to leave the vessel. Several other space-suited figures gathered in the airlock with him, and he suspected that most if not all of the ship’s crew were “going ashore” at the same time though, of course, they might not be crew; one operator could

handle a vessel of the Karella’s class. He wondered whether or not this was considered safe practice on a foreign planet; but a careful look around as he walked the short distance from ship to dome revealed no defensive armament, and suggested that those manning the station had no anxiety about attack. If, as had been suggested, the post had been here for twenty years, they probably should know.

The interior of the dome was comfortable enough, though Ken’s conductor made constant apology for the lack of facilities. They had a meal for which no apology was required, and Ken was shown private quarters at least as good as were provided by the average Sarrian hotel. Laj Drai took him on a brief tour of the station, and made clear the facilities which the scientist could use in his assigned job.

With his “real” job usually in mind, Ken kept constant watch for any scrap of evidence that might suggest the presence of the narcotic he sought. He was reasonably certain, after the tour, that there was no complex chemical processing plant anywhere around; but if the drug were a natural product, there might not have to be. He could name more than one such substance that was horribly effective in the form in which it was found in nature — a vegetable product some primitive tribes on his own world still used to poison their arrows, for example.

The “trading” equipment, however, proved more promising, as might have been foreseen by anyone who had considered the planet with which the trading was done. There were many remote-control torpedoes, each divided into two main sections. One of these contained the driving and control machinery and was equipped with temperature control apparatus designed to keep it near normal; the other was mostly storage space and refrigeration machinery. Neither section was particularly well insulated, either from the other or the surrounding medium. Ken examined one of the machines minutely for some time, and then began asking questions.

“I don’t see any vision transmitter; how do you see to control the thing on the planet’s surface?”

“There is none,” a technician who had been assisting Drai in the exposition replied. “They all originally had them, of course, but none has survived the trip to Three yet. We took them out, finally — it was too expensive. The optical apparatus has to be exposed to the planet’s conditions at least partly, which means we must either run the whole machine at that temperature or have a terrific temperature difference between the optical and electrical elements. We have not been able to devise a system that would stand either situation — something goes completely haywire in the electrical part under those freezing conditions, or else the optical section shatters between the hot and cold sections.”

“But how do you see to control?”

“We don’t. There is a reflection altimeter installed, and a homing transmitter that was set up long ago on the planet. We simply send the torpedo down, land it, and let the natives come to it.”

“And you have never brought any physical samples from the surface of the planet?”

“We can’t see to pick up anything. The torpedo doesn’t stay airtight at that temperature, so we never get a significant amount of the atmosphere back; and nothing seems to stick to the outer hull. Maybe it lands on a solid metal or rock surface — we wouldn’t know.”

“Surely you could make the thing hold air, even below the freezing point of sulfur?”

“Yes, I guess so. It’s never seemed to be worth the trouble. If you want a sample, it would be easier to send a smaller container down, anyway — you can work with it better afterwards.”

A thought suddenly struck Ken.

“How about the stuff you get from the natives? Doesn’t that give any clue? Could I work with some of it?” Laj Drai cut in at this point.

“You said you were not a specialist. We have tried to get the stuff analyzed by people who were, without success. After all, if it were possible to synthesize the material, do you think we’d be going to all this trouble to trade for it? That’s why we want you to get the planetary conditions for us — when you’ve done that, we’ll figure out a means of getting seeds from the natives and growing our own.”

“I see,” Ken replied. The statement was certainly reasonable enough, and did not necessarily imply anything about the nature of the material they were discussing.

It did not refute anything, either.

Ken thought that one over for a time, letting his eyes wander over the exposed machinery as he did so. He had a few more questions in mind, but he wanted to dodge anything that might be interpreted as unhealthy curiosity, if these people actually were drug-runners.

“What do these natives get from you for this product?” he asked finally. “Is it a manufactured article they can’t make, or a substance they don’t have? In the latter case, I might be able to draw some conclusions about the planet.” Drai sent a ripple down his tentacles, in a gesture equivalent to a human shrug.

“It’s material — heavy metals that don’t sulfide easily. We’ve been giving them platinum-group nuggets most of the time — they’re easiest to come by; there’s an outcropping of the stuff only a short distance from this station, and it’s easy to send a man out to blast off a few pieces. I don’t know what they use them for — for all I know they may worship the torpedo, and use the nuggets as priests’ insignia. I can’t say that I care, as long as they keep filling their end of the bargain.” Ken made the gesture of agreement, and spoke of something which had caught his attention during the last speech.

“What in the Galaxy is a loudspeaker and microphone doing in that thing? Surely they don’t work at the temperatures you mentioned — and you can’t be speaking to these natives!”

The technician answered the first question.

“It works, all right. It’s a crystal outfit without vacuum tubes, and should work in liquid hydrogen.”

Drai supplemented the other answer. “We don’t exactly talk to them, but they can apparently hear and produce sounds more or less similar to those of our speech.”

“But how could you ever have worked out a common language, or even a code, without visual contact? Maybe, unless you think it’s none of my business and will not be any help in what is, you’d better give me the whole story from the beginning.”

“Maybe I had,” Laj Drai said slowly, draping his pliant form over a convenient rack. “I have already mentioned that contact was made some twenty years ago— our years, that is; it would be nearer thirty for the natives of Planet Three.

“The Karella was simply cruising, without any particular object in view, when her previous owner happened to notice the rather peculiar color of Planet Three. You must have remarked that bluish tint yourself. He put the ship into an orbit at a safe distance beyond the atmosphere, and began sending down torpedoes. He knew better than to go down himself — there was never any doubt about the ghastly temperature conditions of the place.

“Well, he lost five projectiles in a row. Every one lost its vision connection in the upper atmosphere, since no one had bothered to think of the effect of the temperature on hot glass. Being a stubborn character, he sent them on down on long-wave instruments, and every one went out sooner or later; he was never sure even whether they had reached the surface. He had some fair engineers and plenty of torpedoes, though, and kept making changes and sending the results down. It finally became evident that most of them were reaching the surface— and going out of action the instant they did so. Something was either smashing them mechanically or playing the deuce with their electrical components.

“Up to then, the attempts had all been to make the landings on one of the relatively smooth, bluish areas; they seemed the least complicated. However, someone got the idea that this steady loss of machines could not be due to chance; somewhere there was intelligent intervention. To test the idea, a torpedo was sent down with every sort of detecting and protecting device that could be stuffed aboard — including a silver mesh over the entire surface, connected to the generators and capable of blocking any outside frequency which might be employed to interfere with control. A constantly changing control frequency was used from our end. It had automatic heat control — I tell you, it had everything. Nothing natural and darned little that was artificial should have been able to interfere with that machine; but it went out like the others, just as the reflection altimeter reported it as almost touching the surface.

“That was enough for the boss. He accepted as a working theory the idea that a race lived on the flatter parts of the planet; a race that did not want visitors. The next torpedo was sent to one of the darker, rougher areas that could be seen from space, the idea being that these beings might avoid such areas. He seems to have been right, for this time the landing was successful. At any rate, the instruments said the machine was down, it proved impossible to drive it lower, and it stayed put with power off.

“That was encouraging, but then no one could think of what to do. We still couldn’t see, and were not certain for some time whether or not the microphone was working. It was decided not to use the loudspeaker for a while. There was a faint humming sound being picked up whose intensity varied without apparent system, which we finally decided might be wind rather than electrical trouble, and once or twice some brief, harsh, quite indescribable noises which have not yet been identified; the best guess is that they may have been the voices of living creatures.

“We kept listening for a full rotation of the planet— nearly two of our days — and heard nothing else except a very faint buzzing, equally faint scratching sounds, and an irregular tapping that might or might not have been the footsteps of a hoofed creature on a hard surface. You may listen to the records we made, if you like, but you’d better have company around when you do. There’s something weird and unnerving about those noises out of nothing.

“I forgot to mention that the cargo port of the torpedo had been opened on landing, and microphones and weight detectors set to tell us if anything went in. Nothing did, however — a little surprising if there were small forms of wild life; the opening would have made a natural-looking shelter for them.

“Nothing even remotely suggestive of intelligence was heard during that rotation; and it was finally decided to use the loudspeaker. Someone worked out a schedule— starting at minimum power, repeating a tape for one rotation of the planet, then repeating with doubled output and so on until we reached the maximum which could be attained with that equipment. The program was followed, except that the boss was getting impatient and arranged to make the step-up each quarter rotation instead of the suggested time. Some humorist recorded a poem on the tape, and we started broadcasting.

“The first result was a complete cessation of the sounds we had tentatively associated with life forms. Presumably they were small animals, and were scared away by the noise. The wind, if that’s what it was, continued as expected. The first time we increased the noise, after a quarter rotation of the planet, we began to get a faint echo. That suggested that the sound was at least not being muffled very close to the speaker, and if any intelligent beings came within a considerable radius they would hear it.

“To make a long story short, we got a response after the fourth increase of power. We thought it was a distorted echo at first, but it got louder while our power remained constant, and finally we could tell that the sounds were different. They formed a tremendously complex noise pattern, and every one of us who heard them was sure from the beginning that they represented intelligent speech.

“Eventually we began to hear more footstep-sounds between the bursts of alien language, and we cut off our own broadcast. It became evident that the creature was close enough to detect the torpedo by other means than hearing, for the footsteps continued to approach. At first they were interrupted every few seconds by a loud call; but presently the thing must have actually reached the machine, for the sounds suggested that it was walking around at a nearly constant distance, and the calls were replaced by much less powerful but longer and more complex speech-noises. Probably the creatures can see much as we do, though the light is so much weaker on that planet.

“Presently the photocell inside the cargo compartment indicated that something had cut off much of the light One of the operators moved to close the door, and the boss knocked him clean out of the control room. He took the torpedo controls himself, and began attempting to imitate the voice sounds of the creature we couldn’t see. That produced results, all right! If noise means anything, the native got wildly excited for a minute or two; then he buckled down to producing apparently as wide a variety of sounds as his vocal apparatus would permit. Certainly we couldn’t imitate them all.

“That lasted for some time, with nobody making any real progress. Nobody had any way of telling what any of the other fellow’s noises meant, of course. It began to look as though we’d gone as far as we could, in learning about the planet, and that the knowledge was not going to do anyone any good.

“Then someone remembered the old swap-boxes. I don’t know whether you’ve heard of them; they were used, I guess, before our race ever left the home planet, when people who didn’t speak each other’s language wanted to trade. They are simply two trays, hinged together, each divided into a number of small compartments. One side is empty, while the compartments of the other are filled with various articles that are for sale. A glass lid covers each of the full compartments, and cannot be removed until something has been placed in the corresponding compartment of the other tray. It takes a pretty stupid savage not to get the idea in fairly short order.

“We didn’t have any such gadget, of course, but it was not difficult to rig one up. The trouble was that we could not tell what had been put in the empty tray until the box came back to us. Since we were more interested in talking than trading, that didn’t matter too much at the time. We sent the box down in another torpedo, homing it on the location signal of the first and hoping the flat-land people wouldn’t detect it, opened the thing up, and waited.

“The native promptly investigated; he was apparently intelligent enough to put curiosity ahead of fear, even though he must have seen the second torpedo in flight. He behaved exactly as expected with the box, though of course we couldn’t watch him — he put something in every compartment of the empty section, and presumably cleaned out the other; but he put most of the stuff back. One of the things he gave us proved useful — the stuff we still trade for — so we sent the box back with only the compartment corresponding to the one he had put that stuff in full. He got the idea, and we’ve been on fine terms ever since.”

“But about the language?”

“Well, we know his words for ‘yes’ and ‘no,’ his names for a few metals, and his name for the stuff he sells us. I can give you either a tape of his pronunciation or a written record, if you want to talk to him.”

“Thanks a lot. That makes the whole situation a good deal clearer. I take it you have had no more trouble from these flatlanders?”

“None. We have carefully avoided contacting any other part of the planet. As I said, our interests are now commercial rather than scientific. Still, if you want to send down machines on your own, I suppose we shouldn’t interfere with you. Please be careful, though; we’d hate to have contact cut off before we were in a position to do our own producing.”

Ken gave the equivalent of a grin. “I notice you are still carefully refraining from telling me what the stuff is. Well, I won’t butt in. That’s none of my business, and I don’t see how knowing it could help me out. Right now, I guess, it would be best for you to give me all the physical data you have on the planet. Then I can make a guess at its atmosphere, and send a torpedo down with equipment to confirm or deny the guess. That will be easier than trying to bring back samples for analysis, I imagine.” Drai pulled himself together from the rack on which he was sprawled, and gave the equivalent of an affirmative nod. “I’m not saying you shouldn’t know what we get from the planet,” he said. “But I shall most certainly make a hammock from the skin of the first member of this organization who lets you find out!” The technician, who had been listening in the background, turned back to the mechanism of another torpedo, and spoke for the first time without looking up.

“That won’t be difficult; there’s little to tell. The planet is about three-tenths larger than ours in diameter, making its volume rather over twice as great as that of Sarr. Its mass is also over twice ours, though its average density is a shade less. Surface gravity is one and a quarter Sarr normal. Mean temperature is a little below the freezing point of potassium. Atmospheric pressure uncertain, composition unknown. Period of rotation, one point eight four Sarr days.”

“I see. You could duplicate temperature readily enough on this planet, by choosing a point far enough around toward the dark side; and if necessary, there wouldn’t be too much trouble in reproducing the periodicity of night and day. Your problem is atmosphere. I’ll spend some time thinking out ways and means of getting that, then.” Sallman Ken moved slowly away in the direction of his assigned quarters. His thoughts were not exclusively occupied with the problem of atmosphere analysis; he was thinking more of a mysterious race inhabiting the flat, bleak plains of Planet Three and the possibility of cutting off trade with the planet — always, of course, assuming that its mysterious product was what he feared.

He was also wondering if he had overdone his disclaimer of interest in the planet’s chief export.

4

A circle of three-mile radius has an area of slightly over twenty-eight square miles, or roughly eighteen thousand acres. It follows that the map prepared by Roger and Edith Wing was not as detailed as it might have been. On the other hand, as their father was forced to admit, a tree-covered mountain side does not offer too many details to put on a map; and the effort the children turned in did show every creek and trail of which Mr. Wing had knowledge. Still more to the point, it showed clearly that they had actually travelled over the area in question. This was the defect in the girl’s experience which he had wanted corrected before she was released from the “stick-to-the-trail” rule.

He looked up presently from the tattered notebook. The family was gathered around the fireplace again, and the two cartographers were ensconced on either arm of his chair. Don was on the floor between the seats with Billy draped across his neck; Marjorie was in her mother’s lap. All were listening for the verdict.

“You seem to have done a pretty good job here,” Mr. Wing said at last. “Certainly anyone could find his way around the area with the aid of this map. Edie, how do you think you could do without it?”

“All right, Dad, I’m sure,” the girl replied in a slightly surprised tone. “Do I have to?” Her father shrugged.

“You know best whether you want to carry this with you all the time. No, you don’t have to, as far as I’m concerned. How have the two of you made out on the patrol schedule?” Roger took over the conversation, curling a little closer to his father’s shoulder and using the map to illustrate his points.

“There are eight trails leading into the three-mile circle at different points. Don and I used to go around the circle each day, going along each one far enough to be sure no one had been using it. There are spots on each which it’s practically impossible to go through without leaving some sort of trail. Going from one trail to another we’d try to cut across places of the same sort — where we could tell if people had been through.

“This time we’re working it a little differently. I’m still checking the ends of those trails, but we’ve been listing places from which people could watch anyone bound away from here — there aren’t nearly so many of those. Edie can cover nearly all of them in two hour-and-a-half walks morning and afternoon — we’ve tried it; and I can do the rest when I take the outer trails. That’s a lot like the way you’ve always worked it when you were going out, anyway; you took a zigzag path, and had us checking for watchers, so that one of us could cut across and warn you if we saw anyone — we never have, that I can remember, but I don’t suppose that proves anything.” Mr, Wing smiled briefly.

“I may be stretching the precautions a little too far,” he said. “Still I have certain reasons for not wanting the place I get the metal to become known. Half a dozen of the reasons are in this room with me. Besides, I think you get fun out of it, and I know it keeps you outdoors where you ought to be this time of year. If two or three more of you grow up to be scientists, we may be able to do some work together that will let us forget about secrecy.”

The younger girl, who had been displaying increasing signs of indignation during her brother’s talk, cut in the instant she thought her father had finished.

“Daddy, I thought I was supposed to be helping with this. I heard Roger say so yesterday, and you said it the first night.”

“Oh? And how did you hear what I said that night? As I recall, the matter was not discussed until after you were in bed. What I said then goes — you can go with either Roger or Edie on their walks, but you still observe the limits when you’re by yourself. Billie, you too! There’ll be plenty of long trips for all of you, without your having to go off on your own, and there’s always been plenty to keep you occupied around here. I’ve been promising for five or six years to get a load of cement up here if you folks would get enough loose rock together to make a dam out here — I’d like a swimming pool myself. Don doesn’t think we need cement for it, but that’s something he’ll have to prove. I’ll be glad if he can do without it, of course.” He leaned back and stretched his legs. Billy promptly transferred his perch from Don’s shoulders to his father’s shins, and put his own oar into the conversation. He wanted one of the trips before his father went prospecting, and expressed himself at considerable length on the subject. Mr. Wing remained non-committal until the striking of the clock brought relief. He pulled in his legs abruptly, depositing the youngster on the floor.

“Small fry to bed!” he pronounced solemnly.

“Story!” yelled Margie. “You haven’t read since we got here!” Her father pursed his lips.

“How long do you suppose it would take them to be ready for bed?” he asked, as though to himself. There was a flurry of departing legs. Mr. Wing turned to the bookcase beside the fireplace, and encountered the grinning face of his second son. “All right, young man, we need some fun — but some of us need discipline, too. Suppose you and Edie save time by popping upstairs and imitating the excellent example of your juniors!” Still chuckling, the two did so.

For some reason, the story lasted until quite late. The beginning was vastly exciting, but the pace calmed down later, and Billy and Margie were both carried up to bed at the end — though they refused to believe the fact in the morning.

Roger tried at breakfast to make the small boy tell the end of the story and was surprised when Billy refused to accept his inability to do so as evidence that he had been asleep. The older boy gave up at last and went to saddle the horses; he was constitutionally unfitted to hold his own in an argument where the opponent’s only words were “I was not either!”

It was shopping day, and Roger’s turn to go down to Clark Fork with his mother to obtain the necessities for the next week. They left as soon after breakfast as the animals could be readied. Edie and the younger children went off on their own; as soon as everyone was away from the house Mr. Wing and Don dressed themselves in hiking clothes and headed east. Roger would have given much to see them go.

The trails were good, and for a couple of hours the two made very satisfactory progress. For the most part they followed the creeks, but once or twice the older man led the way over open spurs of rock which involved considerable climbing.

“This is about the quickest way to the transmitter, Don,” he said at one point. “It’s a lot closer to the house than even your mother realizes — though goodness knows I wouldn’t hide it from her if she cared to come on one of these hikes. On the regular trips, I follow a very roundabout path I worked out years ago when I was really afraid of being followed. That was just after the first World War, long before I’d even met your mother. There were a number of people around this part of the country then who would cheerfully have tossed me off a hilltop for a fraction of the value I brought back from the first trip. I tell you, I did some pretty serious thinking on the way in from that trip. You’ll see why very shortly.”

Don made no immediate answer to this. His attention seemed to be fully taken up with negotiating the slope of loose rock they were traversing at the moment. It was a section practically impossible to cross without leaving prominent traces, and he had been a little puzzled at his father’s going this way until he realized that the idea was probably to permit a check on any trailers as they returned. Once across the treacherous stuff and angling back down the slope, he finally spoke.

“You said a while back, Dad, that we were the reasons you didn’t make public this source of metal. It seems to me that even that shouldn’t have carried weight while the war was on — it might have been better to let the government develop the find and use it. I don’t mean that I don’t appreciate getting a college education, but — well—” he paused a little uncomfortably.

“You have a point, son, and that was another matter for thought when the war started, with you in high school and Billy just learning to walk. I think I might have done as you suggest, except for the fact that the most probable result of publicity would be to remove the source of metal. Just be patient a little longer — we’ll be there in a few minutes, and you will see for yourself.”

Donald nodded acceptance of this, and they proceeded in silence for a short time. The course Mr. Wing was following had led them into a narrow gully after crossing the scree; now he turned up this, making his way easily along the bank of the tiny brook which flowed down its center. After some ten minutes’ climb the trees began to thin out, and a few more rods found them on practically bare rock. This extended for some distance above them, but the older man seemed to have no desire to get to the top of the hill.

Instead, he turned again, moving quickly across the bare rock as though a path were plainly marked before him; and in a few steps reached the edge of a shallow declivity which appeared to have acted as a catch basin for rocks which had rolled from farther up the hill. Winding his way among these, with Donald close at his heels, he finally stopped and moved to one side, permitting his son to see what lay before them.

It was an almost featureless structure of metal, roughly cubical in shape and a little less than a yard on each edge. There was a small opening on one side, containing a single projection which had the appearance of a toggle switch. Several bolt heads of quite conventional appearance were also visible on different parts of the surface.

After allowing his son to look the object over for a few moments, Mr. Wing took a small screwdriver from his pocket and set to work on the bolts, which seemed very loose. Don, lacking tools, tried a few of the projecting heads with his fingers and had little difficulty with them; in two or three minutes, the older man was able to remove several metal plates and expose the interior of the block to view. Don looked, and whistled.

“What is it, Dad? Not an ordinary radio, certainly!”

“No. It seems to be a radio of some sort, however. I don’t know what sort of wave it uses, or its range, or its power source — though I have some ideas about the last two. There’s nothing to using it; I imagine the makers wanted that to be easy, and there is only the single control switch. I’m not so sure that the interior was meant to be so accessible.”

“But where did it come from? Who made it? How did you get hold of it?”

“That’s a rather long story, and happened, as I said, before you were born.

“I was just out of college, and had gotten interested in this part of the country; so I decided to see some of it first hand, and eventually found myself here in the hills. I started at Helena, and went on foot up to Flathead, through Glacier Park, west along the border to the Kootenai, and back along the river past Bonner’s Ferry into the Cabinets. It wasn’t a very exciting jaunt, but I saw a lot and had a pretty good time.

“I was crossing the brook we just followed up here, just after I had gotten under way one morning, when I heard the weirdest racket from up the hill. I really didn’t know too much about the neighborhood, and was a bit on the uneasy side; but I had a rifle, and managed to convince myself that I was out to satisfy my curiosity, so I headed up toward the noise.

“When I got out from among the trees, the noise began to sound more and more like spoken language; so I yelled a few words myself, though I couldn’t understand a word of it. There was no answer at first — just this tremendous, roaring voice blatting out the strangely regular sounds. Finally, a little way up the hill from here, on a rather open spot, I saw the source; and at almost the same instant the noise stopped.

“Lying out in the open, where it could be seen from any direction, was a thing that looked like a perfectly good submarine torpedo — everyone was familiar with those at the time, as they played a very prominent part in the first World War. Science-fiction had not come into style then, and Heaven knows I wasn’t much of a physical scientist, but even so I found it hard to believe that the thing had been carried there. I examined it as thoroughly as I could, and found a few discrepancies in the torpedo theory.

“In the first place, it had neither propellers nor any type of steering fin. It was about twenty feet long and three in diameter, which was reasonable for a torpedo as far as I knew, but the only break in the surface was a section of the side, near what I supposed to be the front, which was open rather like a bomb bay. I looked in, though I didn’t take a chance on sticking an arm or my head inside, and saw a chamber that occupied most of the interior of the nose section. It was empty, except for a noticeable smell of burning sulfur.

“I nearly had a heart attack when the thing began talking again, this time in a much lower tone — at any rate I jumped two feet. Then I cussed it out in every language

I knew for startling me so. It took me a minute or two to get command of myself, and then I realized that the sounds it was making were rather clumsy imitations of my own words. To make sure, I tried some others, one word at a time; and most of them were repeated with fair accuracy. Whoever was speaking couldn’t pronounce ‘P’ or ‘B,’ but got on fairly well with the rest.

“Obviously there was either someone trapped in the rear of the torpedo, or it contained a radio and someone was calling from a distance. I doubted the first, because of the tremendous volume behind the original sounds; and presently there was further evidence.

“I had determined to set up camp right there, early as it was. I was going about the business, saying an occasional word to the torpedo and being boomed at in return, when another of the things appeared overhead. It spoke, rather softly, when it was still some distance up — apparently the controllers didn’t want to scare me away! It set-tied beside the first, trailing a thin cloud of blue smoke which I thought at first must have to do with driving rockets. However, it proved to be leaking around the edges of a door similar to that in the first torpedo, and then a big cloud of it puffed out as the door opened. That made me a little cautious, which was just as well — the metal turned out to be hot enough to feel the radiation five feet away. How much hotter it had been before I can’t guess. The sulfur smell was strong for a while after the second torpedo landed, but gradually faded out again.

“I had to wait a while before the thing was cool enough to approach with comfort. When I did, I found that the nose compartment this time was not empty. There was an affair rather like a fishing-box inside, with the compartments of one side full of junk and those on the other empty. I finally took a chance on reaching in for it, once it was cool enough to touch.

“When I got it out in the sunlight, I found that the full compartments were covered with little glassy lids, which were latched shut; and there was a: tricky connection between the two sides which made it necessary to put something in an empty compartment and close its lid before you could open the corresponding one on the other side. There were only half a dozen spaces, so I fished out some junk of my own — a wad of paper from my notebook, a chunk of granite, a cigarette, some lichen from the rocks around, and so on — and cleaned out the full compartments. One of the things was a lump of platinum and related metals that must have weighed two pounds.

“Right then I settled down to some serious thinking. In the first place, the torpedo came from off this planet. The only space ship I’d ever heard of was the projectile in Jules Verne’s story, but people of this planet don’t send flying torpedoes with no visible means of propulsion carrying nuggets of what I knew even then was a valuable metal; and if they do, they don’t call attention to the practice by broadcasting weird languages loudly enough to be heard a mile away.

“Granting that the torpedo came from outer space, its behavior seemed to indicate only one thing — its senders wanted to trade. At any rate, that was the theory I decided to act on. I put all the junk except the platinum nugget back where it came from, and put the box back in the nose of the torpedo. I don’t yet know if they could see me or not — I rather doubt it, for a number of reasons — but the door closed almost at once and the thing took off — straight up, out of sight. I was sorry I hadn’t had much of value to stuff in my side of the box. I had thought of sending them a rifle cartridge to indicate we had a mechanical industry, but remembered the temperature at which the thing had arrived and decided against it.

“It took two or three hours for the torpedo to make its round trip. I had set up my tent and rounded up some firewood and water by the time it came back, and I found out my guess was right. This time they had put another platinum nugget in one compartment, leaving the others empty; and I was able to remember what I had put in the corresponding space on the previous visit.

“That about tells the story.” Mr. Wing grinned at his son. “I’ve been swapping cigarettes for platinum and indium nuggets for about thirty years now — and you can see why I wanted you to study some astronomy!” Don whistled gently.

“I guess I do, at that. But you haven’t explained this,” he indicated the metal cube on which his father was sitting.

“That came down a little later, grappled to a torpedo, and the original one took off immediately afterwards. I have always supposed they use it to find this spot again. We’ve sort of fallen into a schedule over the years. I’m never here in the winter any more, and they seem to realize that; but from two to three days after I snap this switch off and on a few times, like this,” he demonstrated, “the exchequer gets a shot in the arm.”

Don frowned thoughtfully, and was silent for a time.

“I still don’t see why you keep it a secret,” he said at last. “If the affair is really interplanetary, it’s tremendously important.”

“That’s true, of course. However, if these people wanted contact with mankind in general, they could certainly establish it without any difficulty. It has always seemed to me that their maintaining contact in this fashion was evidence that they did not want their presence generally known; so that if experts began taking their transmitter apart, for example, or sending literature and machinery out to them in an effort to show our state of civilization, they would simply leave.”

“That seems a little far-fetched.”

“Perhaps; but can you offer a better suggestion why they don’t land one of these things in a city? They’re paying tremendous prices for darned small quantities of tobacco — and a corner drug store could stock them for years at their rate of consumption.

“Don’t get me wrong, son; I certainly appreciate the importance of all this, and want very much to find out all I can about these things and their machines; but I want the investigating done by people whom I can trust to be careful not to upset the apple cart. I wish the whole family were seven or eight years older; we’d have a good research team right here. For the moment, though, you and I — principally you — are going to have to do the investigating, while Rog and Edie do the scouting. I expect they’ll sneak over to watch us, of course; Roger’s curiosity is starting to keep him awake nights, and he has the makings of a man of action. I’m wondering whether we don’t find his tracks or Edie’s on the way back — he might have persuaded her to go to town for him. There’s nothing more to be done here, unless you want to look this communicator over more closely; we might as well head back, and find out how enterprising the younger generation is.”

“There’s no hurry, Dad. I’d like to look this thing over for a while. It has some of the earmarks of a short wave transmitter, but there are a lot of things I’d like to get straight.”

“Me, too. I’ve learned a good deal about radios in the last twenty years, but it’s a bit beyond me. Of course, I’ve never dared take off more than the outer casing; there are parts too deeply stowed to be visible, which might be highly informative if we could see them.”

“Exactly what I was thinking. There should be some way to look into it — we ought to dig up one of those dentist’s mirrors.”

“You don’t catch me sticking anything made of metal into a gadget that almost certainly uses astronomical voltages.”

“Well — I suppose not. We could turn it off first, if we were sure which position of that switch were off. We don’t really know whether you’re calling them with a short transmission when you move it, or whether you’re breaking a continuous one. If they use it for homing, it would be the latter; but we can’t be sure.”

“Even if we were, turning it off wouldn’t be enough. Condensers can hold a nasty bite for a long time.”

Don admitted the justice of this point, and spent only a few minutes peering through the openings left by the removal of the plates.

“Most of the inside seems to be blocks of bakelite anyway,” he said at last. “I suppose they have everything sealed in for permanence. I wonder how they expect to service it? I guess you’re right — we may as well go home until the torpedo comes.” He slung the pack that had contained their lunch — or rather, the sandwiches they had eaten in route — over his shoulder, and straightened up. His father nodded in agreement, and they began to retrace their steps down the hillside.

Don was wrapped in thought, and his father forbore to interrupt. He knew how he had reacted to the events he had just described, when he had been very little older than his son was now; also, he had a high opinion of his children’s intelligence, and believed firmly in letting them solve problems for themselves as much as was safe. He reflected somewhat ruefully that nothing he could say would be too much help, in any case.

There was no trace of anyone’s having followed them at any point on the trail home, though they split up to take opposite sides of the scree they had deliberately crossed on the way out. Neither found this very surprising, for it turned out that Edith had made her scheduled patrols and spent the rest of the day with the younger children, while Roger had gone to town as expected. If he had thought of finding a substitute and following his father, nothing had come of it. Mr. Wing was not sure whether he ought to be pleased or disappointed.

5

Laj Drai found his hired schoolteacher beside one of the torpedoes, checking off its contents with loops of one tentacle. The mechanic was listening as he named off the items.

“Magnesium cell; titanium cell; sodium — oh, hello, Drai. Anything going on?”

“Hard to say. You are setting up a research project, I take it?”

“Just checking some hypotheses. I’ve listed all the elements that would be gaseous under the conditions of Planet Three, and as many compounds as I could find in the Tables. Some are a little doubtful, since I have no pressure data; they might be liquid. Still, if they are there in any quantity, their vapors should be present.

“Then I eliminated as many as possible on theoretical grounds, since I can’t test for everything at once.”

“Theoretical grounds?”

“Yes. For example, while fluorine is still gaseous under those conditions, it’s much too active to be expected in the free state. The same is true of chlorine — which may be liquid — and oxygen. On the other hand, hydrogen seems very likely, along with hydrogen sulfide and other volatile compounds of both those elements. Nitrogen should be present, and the inert gases — though I don’t know how I can test for those.

“I’ve built little cells containing various materials, along with built-in heaters; and I’m going to warm them up one at a time after landing this torpedo and opening it to the atmosphere. Then I’ll bring it back and see what the air did to my samples. I have magnesium and titanium, which should detect the nitrogen, and sodium, and a couple of sulfides which should be reduced if there’s much hydrogen, and so on. The report may not be complete, but we should learn something.”

“So I should say, from what little I know about it Were you planning to send the torpedo out right away?”

“Yes; everything seems to be ready, unless there are complications from your department.”

“Nothing much. We were just going to send one out ourselves; our native signalled a short time ago.”

“Can you control two torpedoes at once?”

“Yes, easily. It occurs to me, however, that it might be best for you to keep a mile or two away from our homing station, and make your descent when that part of the planet is in darkness. The natives are diurnal, we are sure; and it would be a pity to scare them off if any of your chemical reactions are bright or noisy or smelly.”

“Or affect some sense we don’t know about. All right; you have a good point. Do you want me to wait until you have finished your trading, or go ahead of you if the chance occurs?”

“I don’t see that it matters much. I don’t remember whether it will be night or day there when the torpedoes arrive overhead; there’s a table for figuring it up in the office, and we’ll check before arrival time. I’d say if it was day, we’d go right down while you waited, and if it’s night you get first shot.”

“All right with me.”

“You’ll have to control from down here — there’s only one unit up in the observatory. It won’t matter, since you’ll be “working blind anyway. I’ll go up and tell them that you’re operating too — we have a relay unit with detection apparatus circling the planet now, and there’s no point in having the observers think the flatlanders are out in space.”

“Have you been getting activity from them?”

“Not much. Within the last three or four years we have picked up some radiation suspiciously like radar, but it’s all been constant frequency so far. We put quarter-wave coatings of plastic with a half-reflecting film of metal on all the torpedoes, and we haven’t had any trouble. They only use a dozen different frequencies, and we’re set up for all of them — when they change, we simply use another drone. I suppose they’ll start using two or more wave lengths in one area or maybe frequency modulation eventually, and we’ll have to get a non-reflective coating. That would be simpler anyway — only it’s more expensive. I learned that when I had the Karella coated. I wonder how we’ll get around it if they learn to pick up infra-red? The torps are enough hotter than the planet to show up like novae, when we happen to start them from the ship just outside the atmosphere.”

“Let ‘em hang in space until they cool off,” Ken and the mechanic replied in chorus. “Or send them all from here, as we’ve been doing,” added the latter. Laj Drai left without further remark.

“That fellow needs a whole scientific college,” the mechanic remarked as the door closed. “He’s so darned suspicious he’ll hire only one man at a time, and usually fires them before long.”

“Then I’m not the first?”

“You’re the first to get this far. There were a couple of others, and he got the idea they were poking into his business, so I never even found out what ideas they had. I’m no scientist, but I’m curious — let’s get this iron cigar into space before he changes his mind about letting it go.”

Ken gestured agreement, but hung back as the mechanic cut the test controller into the main outside beam circuit — two multiphase signals could be handled as easily as one on the beam, and both torpedoes would be close enough together so that one beam would suffice. The mechanic’s information was interesting; it had never occurred to him that others might have preceded him on this job. In a way, that was good — the others had presumably not been narcotics agents, or Rade would have told him. Therefore he had better protective coloration than he had supposed. Drai might even be getting used to having outsiders connected with his project.

But just what did this mechanic know? After all, he had apparently been around for some time, and Drai was certainly not afraid to talk in his presence. Perhaps he might be worked up into a really effective source of information; on the other hand, it might be dangerous to try — quite conceivably one of his minor duties was keeping a watchful eye on Sallman Ken’s behavior. He was a rather taciturn individual and Ken had not given him much attention so far.

At the moment he was all technician. He was draped over the rack in front of the control board, his tentacles resting on the various toggles and verniers, and a rising hum indicated that the tubes were warming. After a moment, he twisted a vernier knob slightly, and the torpedo on which Ken had been working lifted gently from the cradle. He spoke without turning his eyes backward:

“If you’ll go to the far end of the room, I’ll run it down there and we can test the microphone and speaker. I know you don’t plan to use them, but we might as well have them serviceable.”

Ken followed the suggestion, testing first the sound apparatus and then the various recorders and other instruments in the cargo chamber which were intended to tell whether or not any violent chemical reactions took place — photocells and pyrometers, and gas pumps connected to sample flasks and precipitators. Everything appeared in working order and was firmly clamped in place.

Assured of this, the operator guided the little vessel to a tunnel-like air lock in one wall of the room, maneuvered it in, pumped back the air, and drove the torpedo out into the vacuum of Mercury’s surface. Without further ado he sent it hurtling away from the planet, its control keyed in with a master achronic beam running from the station to the relay unit near Earth. No further attention would be needed until it approached the planet.

The mechanic rose from in front of the panel, and turned to Ken.

“I’m going to sleep for a while,” he said. “I’ll be back before arrival time. In case you care, you’ll be making the first landing. It takes one and a half revolutions of Planet Three, more or less, to get the torpedo there when the planets are in their present relative positions — we can’t use overdrive on the drones — and the signal must have come during the local daytime. I’ll see you. Have me paged if you want me for anything.”

Ken gave the equivalent of an affirmative nod.

“All right — and thanks. Your name is Allmer, isn’t it?”

“Right — Feth Allmer.” Without further speech the mechanic disappeared through the door, moving with the fluid ease of a person well accustomed to Mercury’s feeble gravity, and leaving Sallman Ken in a very thoughtful mood behind him.

Almost unconsciously the investigator settled onto the rack deserted by Allmer, and stared blankly at the indicators in front of him. One of his troubles, he reflected ruefully, was his tendency to get interested in two problems at once. In one way, that might be good, of course; the genuine absorption in the problem of Planet Three was the best possible guard against suspicion of his other job; but it didn’t help him to concentrate on that other. For hours now he had thought of practically nothing but his test project, until Allmer’s parting remarks had jarred him back to duty.

He had assumed Allmer was a competent technician, but somehow he had not expected the acuity the elderly fellow had just displayed. Ken himself had missed the implication of Drai’s statement concerning the habits of the natives of the third planet; apparently Drai had not even thought of doing his own reasoning.

But could he be that stupid? He, unlike Ken, knew the distances involved in a flight to that world, and the speed of the torpedoes; he had, on his own word, been trading here for years. What purpose could he have in trying to appear more stupid than he really was?

One possibility certainly existed. Ken might already be under suspicion, and facing a conspiracy to make him betray himself by overconfidence. Still, why in that case had the mechanic betrayed his own intelligence? Perhaps he was building himself up as a possible confidant, in case Ken were to grow communicative. If that were so, Feth was his greatest danger, since he was most in Ken’s company and in best position to serve as a spy. On the other hand, the fellow might be completely innocent even if the group as a whole were engaged in smuggling, and his recent words might have been motivated by a sincere desire to be helpful. There seemed no way of telling at the moment which of these possibilities was the more likely; Ken gave the problem up for the moment as insoluble with the data on hand.

The other problem was demanding his attention, anyway. Some of the indicators on the board in front of him were fluctuating. He had learned the panel fairly well in the last day or two, and was able to interpret the readings himself. It seemed, he noted, that pressure and temperature were both going down in the cargo chamber of the projectile. Well, that was reasonable. There were no heaters working, and the pressure would naturally drop as the gas cooled. Then it occurred to him that the temperature of Planet Three was low enough to freeze sulfur, and his test units would be covered with a crust of the stuff. Something should be done about that.

As a matter of fact, most of the pressure drop was due to leakage; the cargo door had cooled and contracted sufficiently to let air escape slowly around its edges. Ken, however, did not think of that; he found the appropriate switch and tripped it, watching the pressure drop instantly to zero as the door opened. The temperature was almost unaffected — if anything, it dropped more slowly, for the recording pyrometers were now insulated by a vacuum and the expansion of the gaseous sulfur into empty space had had no cooling effect to speak of. A touch on some of the switches which were designed to heat the test substances showed that the little furnaces were still in working order, and after a moment’s thought Ken allowed the magnesium and titanium specimens to come up to melting temperature. Then, sure that they were as free of contaminating gases as could be managed, he watched the recorders as the samples cooled again. Through all this, the torpedo hurtled on, unaffected by the extra drain on its power.

For some minutes Ken continued to wait, one eye roving over the dials and the other glancing casually about the great room; but finally he decided that Allmer had picked a good time to go off duty. He did not feel tired himself, but gradually he became convinced that there must be something a little more constructive to do. He suspected that, even if there were to be any drugs around the station, they would not have arrived yet, so there was no use making a search for them; but preparations might be made to see just what came back in the other torpedo.

As a first step, it might be well to go up to the observatory to find out just who was guiding that missile. If it were Drai himself, it would be a point in favor of Rade; if not, it would be another person from whom information might be obtained. There seemed little doubt that no one would be allowed to run the trading torpedo who did not know exactly what was being obtained on the third planet — the Planet of Ice, as Ken was coming to think of it (not that he thought of ice as a substance; he had never seen the material and would have thought of it as hydrogen oxide in any case. Planet of Solid Sulfur comes closer to the way he would have expressed the thought).

Ken was basing his supposition on his memory of how Drai had refrained from naming the substance obtained from the planet; and, determined to find at least one small brick of data to add to his edifice of information, the investigator headed up the spiral ramp toward the observatory at the station’s highest level. No one attempted to stop him on the way, though he met a couple of workers who flipped tentacles in casual recognition. The door of the observatory was not locked, as a trial push showed, and he entered, still without opposition. He was braced for a prompt request to depart, and was a little surprised when nothing at all was said. A moment later, when his eyes had become accustomed to the dimness of the big room, he realized to his chagrin that no one was there.

“No business secrets loose so far,” he muttered.

He was about to return the way he had come, when it occurred to him that he might as well make sure of that fact. There were not many places where paper work of any sort could be kept, at least at first glance; and these he rapidly covered. They were mostly cabinets built under instrument panels, and seemed to contain nothing but tables of the motions of the planets of this system. These seemed rather valueless; their most probable use would be in navigation, and Ken could not imagine anyone’s wanting to navigate anywhere in this system except to the world of Ice. They could also be used to direct the instruments, if anyone wanted to look at the planets in question; but that seemed even less helpful.

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

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

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

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

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

6

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

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

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

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

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

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

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

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

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

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

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

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

“Can’t you decelerate faster?”

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

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

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

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

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

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

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

Feth Allmer gave the equivalent of a nod.

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

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

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

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

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

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

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

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

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

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

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

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

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