“I’m afraid I was thinking of merely detecting lights,” said Tebbetts. “Pinpointing the sources will be harder, especially from here. I’m pretty sure we can solve your problem, though… that is, if your missing helis are shining their lights. If you think they may have crashed, I shouldn’t think there’d be much chance of light, but I’ll get right to it.”

“How about their power plants?” asked Barlennan, demanded to learn the worst now that he had started. “Aren’t there other radiations than light given off in nuclear reactions?”

By the time this question reached the station Tebbets had left according to his promise, but fortunately Benj was able to supply the answer — the information happened to be basic to the Project, which had been carefully explained to him right after his arrival.

“The fusion converters give off neutrinos which we can detect, but we can’t spot their source exactly,” he told the commander. “That’s what the shadow satellites are for. They detect neutrinos, which are practically all coming from the sun. The power plants on Dhrawn and up here don’t count for much against that, even if it isn’t much of a sun. The computers keep track of where the satellites are, and especially wheter the planet is between a given one and the sun, so there’s a measure of the neutrino absorption through different parts of the planet. In a few years we hope to have a statistical X ray of Dhrawn — maybe that isn’t a good analogy for you. I mean a good idea of the density and composition of the planet’s insides. They’re still arguing, you know, wheter Dhrawn should be called a planet or a star, and wheter the extra heat is from hydrogen fusion in the middle or radioactivity near the surface.

“But I’m sure as can be that they couldn’t find your missing fliers from their neutrino emission, even if all their converters are still on.”

Barlennan managed to conceal his glee at this news, and merely answered, “Thanks. We can’t have everything. I take it you’ll tell me when your astronomer finds anyth9ng, or when he is sure he’ll find nothing; I’d like to know if I have to stop counting on that. I’m through talking for now, Benj, but call here if anything comes up on either the fliers or those friends of yours — after all, I’m concerned about them, though perhaps not the way you are about Beetchermarlf. Takoorch is the one I remember.”

Barlennan, with more direct contact with human beings and, to be honest, more selfish reasons to develop such skills, had been able to read more accurately between the lines of Benj’s talk and obtain a more nearly correct picture of the boy’s feelings than Dondragmer had. It would, he was sure, be useful; but he put it from his mind as he turned away from the communicator.

“That could be bother better and worse,” he remarked to the two scientists. “It’s certainly just as well we didn’t set up that blinker system for night communication; they’d have seen us certainly.”

“Not certainly,” objected Deeslenver. “The human said they could spot such slights, but there was no suggestion that they made a habit of looking for them If it takes instruments, I’d bet the instruments are busy on more important things.”

“So would I, if the stakes weren’t so high,” returned Barlennan. “Anyway, we wouldn’t dare use it now, because we know they’ll be looking this way with the best machines they have. We just asked them to.”

“But they won’t be looking here. They’ll be searching the neighborhood of the Kwembly, millions of cables from here.”

“Think of yourself back home looking up at Toorey. If you were supposed to examine one part of it closely with a telescope, how much of a slip would it take to make you glance at another?”

Deeslenver conceded the point with a gesture.

“Then we either wait for sunrise, or fly a special if we want to use the Esket as you suggested. I admit I haven’t thought of anything else. I haven’t even thought of what we might do there which would make a good test.”

“It shouldn’t matter too much. The real question would be how soon, and how accurately and completely, the human beings do report whatever we set up for them to see. I’ll think of something in the next couple of hours. Aren’t you researchers setting up for a flight to leave soon, anyway?”

“Not that soon,” said Bendivence. “Also, I don’t agree with you that details don’t matter. You don’t want hem to get the idea that we could possibly have anything to do with that they see happen at the Esket, and they certainly aren’t stupid.”

“Of course. I didn’t mean that they should. It will be something natural, making full allowance for the fact that the human beings know even less than we do about what’s natural on this world. You get back to the labs and tell everyone who has equipment to get onto the Deedee that departure time has been moved ahead. I’ll have a written message for Destigmet in two hours.”

“All right.” The scientists vanished through the door, and Barlennan followed them more slowly. He was just beginning to realize how valid Bedivence’s point was. What could be made to happen, in range of one of the Esket’s vision transmitters, which would not suggest that there were Mesklinites in the neighborhood, but which would attract human interest — and tempt the big creatures to edit their reports? Could he think of such a thing without knowing why the reports were being held up? Or, for that matter, without being quite sure that they were?

It was still possible that the delay on the Kwembly matter had been a genuine oversight; as the young human had suggested, each person might have thought that someone else had attended to the matter. To Barlennan’s sailor’s viewpoint this smacked of gross incompetence and inexcusable disorganization; but it would not be the first time he had suspected human beings — not as a species, of course, but on an individual basis — of these qualities.

The test certainly had to be made, and the Esket’s transmitters must surely be possible tools for the purpose. As far as Barlennan knew, these were still active. Naturally, care had been taken that no one enter their field of view since the “loss” of the cruiser, and it had been long since any human being had made mention of them. They would have been shuttered rather than avoided, since this obviously left the Mesklinites at the place much greater freedom of action; but the idea of the shutters had not occurred until after Destigmet had departed with his instructions to set up a second Settlement unknown to the human beings.

As Barlennan remembered, one of the transmitters had been at the usual spot on the bridge, one in the laboratory, one in the hangar where the helicopters were kept — these had been out on routine flights when the “catastrophe” occurred — and the fourth in the life-support section, though not covering the entrance. It had been necessary to take much of the equipment from this chamber, of course.

With all the planning, the situation was still inconvenient; having the lab and life rooms out of bounds, or at best possible to visit with only the greatest care, , had caused Destigmet and his first officer caused Destigmet and his first officer, Kabremm, much annoyance. They had more than once requested permission to shutter the sets, since the technique had been invented. Barlennan had refused, not wanting to call human attention back to the Esket; but now — well, maybe the same net could take two fish. The sudden blanking of one, or perhaps all four, of those screens would certainly be noticed from above. Wheter the humans would feel any inclination to hide the event from the Settlement there was no way of telling; one could only try.

The more he thought it over, the better the plan sounded. Barlennan felt the glow familiar to every intelligent being, regardless of species, who has solved a major problem unassisted. He enjoyed it for fully half a minute. At the end of that time, another of Guzmeen’s runners caught up with him.