Arthur Clarke - Earthlight

“Please find Mr. Sadler for me. I want to speak to him again.”

There had been a subtle change in Sadler’s status since the director’s return. It was something that Sadler had known must happen, though he had done his best to guard against it. On his arrival, he had been treated with polite suspicion by everybody, and it had taken him several days solid public-relations work to break down the barriers. People had become friendly and talkative, and he could make some headway. But now they seemed to be regretting their earlier frankness, and it was uphill work once more.

He knew the reason. Certainly no one suspected his real purpose in being here, but everybody knew that the return of the director, far from limiting his activities, had somehow enhanced his position. In the echoing sounding-box of the Observatory, where rumor and gossip traveled at speeds scarcely inferior to that of light, it was hard to keep any secrets. The word must have gone out that Sadler was more important than he seemed. He only hoped it would be a long while before anybody guessed how much more important…

Until now, he had confined his attention to the Administrative section. This was partly a matter of policy, because this would be the way he would be expected to act. But the Observatory really existed for the scientists, not the cooks, typists, accountants and secretaries, however essential they might be.

If there was a spy in the Observatory, there were two main problems he had to face. Information is useless to a spy unless he can send it to his superiors. Mr. X must not only have contacts who passed material to him—he must have an out-going channel of communication as well.

Physically, there were only three ways out of the Observatory. One could leave it by monorail, by tractor, or on foot. The last case did not seem very likely to be important. In theory, a man might walk a few kilometers and leave a message to be picked up at some prearranged rendezvous. But such peculiar behavior would soon be noticed, and it would be very easy to check on the small number of men in Maintenance who were the only people who used suits regularly. Every exit and entrance through the airlocks had to be logged, though Sadler doubted that this rule was invariably obeyed.

The tractors were more promising, as they would give so much greater range. But their use would involve collusion, since they always carried a crew of at least two men—and this was one rule which was never broken, for safety reasons. There was the odd case of Jamieson and Wheeler, of course. Their backgrounds were being busily investigated now, and he should have the report in a few days. But their behavior, though irregular, had been too open to be really suspicious.

That left the monorail to Central City. Everybody went there, on the average, about once a week. There were endless possibilities for the exchange of messages here, and at this very moment a number of “tourists” were inconspicuously checking contacts and making all sorts of interesting discoveries about the private lives of the Observatory staff. There was little part that Sadler could play in this work, except to furnish lists of the most frequent visitors to the City.

So much for physical lines of communication. Sadler discounted them all. There were other, and subtler, means far more likely to be used by a scientist. Any member of the Observatory’s staff could build a radio transmitter, and there were countless places where one could be concealed. It was true that the patiently listening monitors had detected nothing, but sooner or later Mr. X would make a slip.

Meanwhile, Sadler would have to find what the scientists were doing. The high-pressure course in astronomy and physics he had taken before coming here would be totally inadequate to give him any real understanding of the Observatory’s work, but at least he would be able to get the general outline. And he might eliminate a few suspects from his depressingly long list.

The Computing Section did not detain him for long. Behind their glass panels, the spotless machines sat in silent cogitation while the girls fed the program tapes into their insatiable maws. In an adjacent sound-proofed room, the electric typewriters stormed away, printing endless rows and columns of numbers. Dr. Mays, the head of the section, did his best to explain what was going on—but it was a hopeless task. These machines had left far behind such elementary operations as integration, such kindergarten functions as cosines or logarithms. They were dealing with mathematical entities of which Sadler had never heard, and solving problems whose very statement would be meaningless to him.

That did not worry him unduly; he had seen what he wanted to. All the main equipment was sealed and locked; only the maintenance engineers who called once a month could get at it. Certainly there was nothing for him here. Sadler tiptoed away as from a shrine.

The optical workshop, where patient craftsmen shaped glass to a fraction of a millionth of an inch, using a technique unchanged for centuries, fascinated him but advanced his search no further. He peered at the interference fringes produced by clashing light waves, and watched them scurry madly back and forth as the heat of his body caused microscopic expansions in blocks of flawless glass. Here art and science met, to achieve perfections unmatched elsewhere in the whole range of human technology. Could there be any clue for him here in this buried factory of lenses, prisms and mirrors? It seemed most improbable.

He was, Sadler thought glumly, rather in the position of a man in a darkened coal cellar, looking for a black cat that might not be there. What was worse, to make the analogy more accurate he would have to be a man who didn’t know what a cat looked like, even when he saw one.

His private discussions with Maclaurin helped him a good deal. The director was still skeptical, but was obviously cooperating to the full if only to get this annoying interloper out of the way. Sadler could question him about any technical aspect of the Observatory’s work, though he was careful not to give any hints as to the direction his search was taking him.

He had now compiled a small dossier for every member of the staff—no mean achievement, even though the factual data had been supplied before he came to the Observatory. For most of his subjects, a single sheet of paper sufficed, but for some he had accumulated several pages of cryptic notes. The facts he was sure of he wrote in ink; the speculations were in pencil so that they could be modified when necessary. Some of these speculations were very wild and frequently libelous, and Sadler often felt very ashamed of them. It was hard, for example, to accept a drink from someone whom you had noted down as possibly susceptible to bribes owing to the cost of maintaining an expensive mistress in Central City…

This particular suspect had been one of the engineers in Construction. Sadler had soon ruled him out as a likely candidate for blackmail, since far from concealing the situation the victim was always complaining bitterly about his inamorata’s extravagances. He had even warned Sadler against incurring similar liabilities.

The filing system was divided into three parts. Section A contained the names of the ten or so men Sadler considered the most probable suspects, though there was not one against whom he had any real evidence. Some were down simply because they had the greatest opportunity for passing out information if they wished to do so. Wagnall was one of these; Sadler was practically certain that the secretary was innocent, but kept him on the list to be on the safe side.

Several others were listed because they had close relatives in the Federation, or because they were too openly critical of Earth. Sadler did not really imagine that a well-trained spy would risk arousing suspicion by behaving in this way, but he had to be on the watch for the enthusiastic amateur who could be just as dangerous. The records of atomic espionage during the Second World War had been very instructive in this respect, and Sadler had studied them with great care.