"And the moon-quakes?"

  "Just a by-product. There's a lot of magnetic rock around here, and I imagine it must get quite a jolt when that field goes on. You probably wouldn't notice that quake even if you were where it started, but our seismographs are so sensitive they can spot a meteor falling twenty kilometers away."

  Sadler listened to the resulting technical argument with great interest. With so many keen minds worrying around the facts, it was inevitable that some would guess the truth—and inevita­ble that others would counter it with their own theories. This was not important; what concerned him was whether anyone showed special knowledge or curiosity.

  But no one did, and Sadler was still left with his discour­aging three propositions: Mr. X was too clever for him; Mr. X was not here; Mr. X did not exist at all. . . .

  Chapter XI

  nova draconis was waning; no longer did it outshine all the suns of the Galaxy. Yet in the skies of Earth it was still

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  brighter than Venus at her most brilliant, and it might be a thousand years before men saw its like again.

  Though it was very near on the scale of stellar distances, N, Draconis was still so remote that its apparent magnitude did not vary across the whole width of the solar system. It shone with equal brilliance above the firelands of Mercury and the nitrogen glaciers of Pluto. Transient though it was, it had turned men's minds for a moment from their own affairs and made them think of ultimate realities.

  But not for long. The fierce violet light of the greatest nova in history shone now upon a divided system, upon planets that had ceased to threaten each other and were now preparing for deeds.

  The preparations were far more advanced than the public realized. Neither Earth nor the Federation had been frank with its people. In secret laboratories, men had been turning toward destruction the tools which had given them the free­dom of space. Even if the contestants had worked in entire independence, it was inevitable that they would have evolved similar weapons, since they were basing them on the same technologies.

  But each side had its agents and counter-agents, and each knew, at least approximately, the weapons which the other was developing. There might be some surprises—any one of which could be decisive—but on the whole the antagonists were equally matched.

  In one respect, the Federation had a great advantage. It could hide its activities, its researches and tests, among the scattered moons and asteroids, beyond any hope of discovery. Earth, on the other hand, could not launch a single ship without the information reaching Mars and Venus within a matter of minutes.

  The great uncertainty that plagued each side was the ef-fiency of its Intelligence. If this came to war, it would be a war of amateurs. A secret service requires a long tradition, though perhaps not an honorable one. Spies cannot be trained overnight, and even if they could, the kind of flair that char­acterizes a really brilliant agent is not easy to come by.

  No one was better aware of this than Sadler. Sometimes he

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  wondered if his unknown colleagues, scattered over the solar system, felt equally frustrated. Only the man at the top could see the complete picture—or something approaching it. He had never realized the isolation in which a spy must work, the horrible feeling that you are alone, that there is no one you can trust, no one with whom you can share your burdens. Since he had reached the Moon, he had—at least to his knowledge —spoken to no other member of Central Intelligence. All his contacts with the organization had been impersonal and in­direct. His routine reports—which to any casual reader would have seemed extremely dull analyses of the Observatory's ac­counts—went by the daily monorail to Central City, and he had little idea what happened to them after that. A few mes­sages had arrived by the same means, and in the event of teal emergency the teleprinter circuit was available.

  He was looking forward to his first meeting with another agent, which had been arranged weeks in advance. Though he doubted if it would be of much practical value, it would give his morale a badly needed boost.

  Sadler had not, to his own satisfaction at least, acquainted himself with all the main aspects of Administration and Tech­nical Services. He had looked (from a respectful distance) into the burning heart of the micro-pile which was the Observatory's main power source. He had watched the big mirrors of the solar generators, waiting patiently for the sunrise. They had not been used for years, but it was nice to have them around in case of any emergency, ready to tap the limitless resources of the sun itself.

  The Observatory farm had surprised and fascinated him most of all. It was strange that in this age of scientific mar­vels, of synthetic this and artificial that, there were still some things in which Nature could not be excelled. The farm was an integral part of the air-conditioning system, and was at its best during the long lunar day. When Sadler saw it, lines of fluorescent lamps were providing substitute sunlight, and metal shutters had been drawn over the great windows which would greet the dawn when the sun rose above the western wall of Plato.

  He might have been back on Earth, in some well-appointed

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  greenhouse. The slowly moving air passed along the rows of growing plants, gave up its carbon dioxide and emerged not only richer in oxygen, but also with that indefinable freshness which the chemists had never been able to duplicate.

  And here Sadler was presented with a small but very ripe apple, every atom of which had come from the Moon. He took it back to his room where he could enjoy it in privacy, and was no longer surprised that the farm was out of bounds to everyone except the men who tended it. The trees would soon be stripped if any casual visitor could wander through these verdant corridors.

  The Signals section was just about as great a contrast as could be imagined. Here were the circuits that linked the Observatory with Earth, with the rest of the Moon, and if neces­sary with the planets direct. It was the greatest and most obvious danger point. Every message that came or went was moni­tored, and the men who operated the equipment had been checked and rechecked by Security, Two of the staff had been transferred, without knowing the reason, to less sensitive jobs. Moreover—even Sadler did not know this—a telescopic camera thirty kilometers away was taking a photograph every minute of the big transmitting arrays which the Observatory used for long-distance work. If one of these radio searchlights happened to point for any length of time in an unauthorized direction, the fact would soon be known.

  The astronomers, without exception, were all very willing to discuss their work and explain their equipment. If they won­ dered at some of Sadler's questions, they gave no sign of it. For his part, he was very careful not to step outside of his adopted role. The technique he used was the frank man-to­ man one: "Of course this isn't really my job, but I'm quite interested in astronomy, and while I'm here on the Moon I went to see all I can. Naturally, if you're too busy at the mo­ ment " It always worked like a charm.

  Wagnall usually made the arrangements and smoothed the way for him. The secretary had been so helpful that at first Sadler wondered if he was trying to safeguard himself, but further inquiry had shown that Wagnall was like that. He was one of those people who cannot help trying to create a good

  impression, simply because they want to be on good terms with everybody. He must find it singularly frustrating, Sadler thought, working for a cold fish like Professor Maclaurin.

  The heart of the Observatory was, of course, the thousand-centimeter telescope—the largest optical instrument ever made by man. It stood on the summit of a slight knoll some distance from the residential area and was impressive rather than elegant. The enormous barrel was surrounded by a gantry-like structure which controlled its vertical movement, and the whole frame­work could rotate on a circular track.

  "It's not a bit like any of the telescopes back on Earth," ex­plained Molton as they stood together inside the nearest obser­vation dome, looking out across the plain. "The tube, for in­stance. That's so we can still work during t
he day. Without it, we'd get sunlight reflected down into the mirror from the supporting structure. That would ruin our observations, and the heat would distort the mirror. It might take hours to settle down again. The big reflectors on Earth haven't got to worry about this sort of thing. They're only used at night—those that are still in action at all."

  "I wasn't sure that there were any active observatories left on Earth," Sadler remarked.

  "Oh, there are a few. Nearly all training establishments, of course. Real astronomical research is impossible down in that pea-soup of an atmosphere. Look at my own work, for instance —ultra-violet spectroscopy. The Earth's atmosphere is com­pletely opaque to the wavelengths I'm interested in. No one ever observed them until we got out into space. Sometimes I wonder how astronomy ever started down on Earth."

  "The mounting looks odd to me," Sadler remarked thought­fully, "It's more like that of a gun than any telescope I've ever seen."

  "Quite correct. They didn't bother about an equatorial mounting. There's an automatic computer that keeps it tracking any star we set it on. But come downstairs and see what hap­pens at the business end."

  Molton's laboratory was a fantastic maze of half-assembled equipment, scarcely any of which Sadler could recognize. When he complained about this, his guide seemed highly amused.

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  "You needn't feel ashamed of that We've designed and built most of it here; we're always trying out improvements. But roughly speaking, what happens is this. The light from the big mirror—we're directly underneath it here—is piped down through that tube over there. I can't demonstrate at the moment, as someone is taking photographs and it's not my turn for another hour. But when it is, I can select any part of the sky I like from this remote-control desk here and lock the instrument on to it. Then all I have to do is to analyze the light with these spectroscopes. You can't see much of their works, I'm afraid—they're all totally enclosed. When they're in use the whole optical system has to be evaluated, because as I mentioned just now even a trace of air blocks the far ultra­violet rays."

  Sadler was suddenly struck by an incongruous thought.

  "Tell me," he said, glancing round the maze of wiring, the batteries of electronic counters, the atlases of spectral lines, "have you ever looked through this telescope?"

  Molton smiled back at him.

  "Never," he said. "It wouldn't be hard to arrange, but there would be absolutely no point in it. All these really big tele­scopes are super-cameras. And who wants to look through a camera?"

  There were, however, telescopes at the Observatory through which one could look without too much trouble. Some of the smaller instruments were fitted with TV cameras which could be swung into position when it was necessary to search for comets or asteroids whose exact locations were unknown. Once or twice Sadler managed to borrow one of these instruments, and to sweep the skies at random to see what he could find. He would dial a position on the remote-control board, then peer into the screen to see what he had caught. After a while he discovered how to use the Aeronautical Almanac, and it was a great moment when he set up the co-ordinates for Mars and found it bang in the middle of the field.

  He stared with mixed feelings at the green-and-ocher disk almost filling the screen. One of the polar caps was tilted slight­ly sunward—it was the beginning of spring, and the great frost-covered tundras would be slowly thawing after the iron

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  winter. A beautiful planet to watch from space, but a hard planet on which to build a civilization. No wonder its sturdy children were losing patience with Earth.

  The image of the planet was incredibly sharp and clear. There was not the slightest tremor or unsteadiness as it floated in the field of view, and Sadler, who had once glimpsed Mars through a telescope on Earth, could now see with his own eyes how astronomy had been liberated from its chains when the atmosphere had been left behind. Earth-bound observers had studied Mars for decades through instruments larger than this, but he could see more in a few hours than they could have glimpsed in a lifetime. He was no nearer to Mars than they had been—indeed, the planet was now at a considerable dis­tance from Earth—but there was no dancing, quivering haze of air to veil his view.

  When he had gazed his fill at Mars, he searched for Saturn. The sheer beauty of the spectacle took his breath away: it seemed impossible that he was not looking at some perfect work of art, rather than a creation of nature. The great yellow globe, slightly flattened at the poles, floated at the center of its intricate system of rings. The faint bands and shadings of atmospheric disturbances were clearly visible, even across two thousand million kilometers of space. And beyond the con­centric girdles of the rings, Sadler could count at least seven of the planet's moons.

  Though he knew that the instantaneously operating eye of the television camera could never rival the patient photo­graphic plate, he also looked for some of the distant nebulae and star clusters. He let the field of view drift along the crowded highway of the Milky Way, checking the image when­ever some particularly beautiful group of stars, or cloud of glowing mist appeared upon the screen. After a while, it seemed to Sadler that he had become intoxicated with the infinite splendor of the skies; he needed something that would bring him back into the realm of human affairs. So he turned the telescope on Earth.

  It was so huge that even under the weakest power he could get only part of it on the screen. The great crescent was shrink­ing fast, but even the unlit portion of the disk was full of

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  interest. Down there in the night were the countless phos­phorescent glows that marked the positions of cities—and down there was Jeannette, sleeping now, but perhaps dream­ing of him. At least he knew that she had received his letter; her puzzled but guarded reply had been reassuring, though its loneliness and unspoken reproach had torn at his heart. Had he, after all, made a mistake? Sometimes he bitterly re­gretted the conventional caution which had ruled the first year of their married life. Like most couples on the overpopulated planet that swam before his eyes, they had waited to prove their compatibility before embarking on the adventure of parent­hood. In this age, it was a definite social stigma to have chil­dren before one had been married for several years—it was a proof of fecklessness and irresponsibility.

  They had both wanted a family, and now that such matters could be decided in advance had intended to start with a son. Then Sadler had received his assignment, and realized for the first time the full seriousness of the interplanetary situa­tion. He would not bring Jonathan Peter into the uncertain future that lay ahead.

  In earlier ages, few men would have hesitated for such a reason. Indeed, the possibility of their own extinction had often made them even more anxious to seek the only immor­tality human beings can know. But the world had been at peace for two hundred years, and if war came now the complex and fragile pattern of life on Earth might be broken into fragments. A woman burdened with a child might have little chance of survival.

  Perhaps he was being melodramatic, and had let his fears overpower his sense of judgment. If Jeannette had known all the facts, she would still not have hesitated; she would have taken the chance. But because he could not talk to her freely, he would not take advantage of her ignorance.

  It was too late for regret; all that he loved lay there on that sleeping globe, sundered from him by the abyss of space. His thoughts had come full circle. He had made the journey from star to man, across the immense desert of the Cosmos to the lonely oasis of the human soul.

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  Chapter XII

  "I'VE no reason TO suppose," said the man in the blue suit, "that anyone suspects you, but it would be difficult to meet in­conspicuously in Central City. There are too many people around, and everybody knows everybody else. You'd be sur­prised how hard it is to get any privacy."

  "You don't think it will seem odd for me to come here?" asked Sadler.

  "No, most visitors do, if they can manage it. It's like going to Niagara Fails—someth
ing no one wants to miss. You can't blame them, can you?"

  Sadler agreed. Here was one spectacle that could never be a disappointment, that would always surpass any advance public­ity. Even now the shock of stepping out onto this balcony had not completely worn off; he could well believe that many people were physically incapable of coming as far as this.

  He was standing above nothingness, encased in a transparent cylinder jutting out from the edge of the canyon. The metal catwalk beneath his feet, and the slim hand rail, were the only tokens of security granted to him. His knuckles still grasped that railing tightly.

  The Hyginus Cleft ranks among the greatest wonders on the Moon. From end to end it is more than three hundred kilo­meters long, and in places it is five kilometers wide. It is not so much a canyon as a series of interlinked craters, branching out in two arms from a vast central well. And it is the gateway through which men have reached the buried treasures of the Moon.