There was no doubt in either Bob's or the Hunter's minds about its being the same object they had seen Apu years before. This was no longer the main question. Bob and Jenny were trying to see what might have caught the Hunter's notice the day before; Maeta, who had no reason to expect anything special, simply reexamined it with interest.

About a third of the metal surface was exposed, and about as much more was so thinly covered with marine growth that its underlying shape was still plain. From the rest, the limy branches grew in random contortions which even the alien found decorative; the branches were covered with the ribbed cups that had once contained living polyps. On the bare metal were patterns of fine scratches which were perfectly legible to the Hunter, though only their essential regularity was apparent to the human beings..

The mere fact that the manufacturer's name, serial number, and various sets of mounting and servicing instructions were present was not the peculiarity which had caught the Hunter's attention the day before. Far more surprising to him was the uniformity with which each of these areas of engraving was ex-posed to view. There were no partly hidden words or phrases or numbers. Each symbol or group of symbols was completely free of coral and other growth, as was the metal for several millimeters around it. The coral did not seem to have been broken away, but it might possibly have been dissolved.

After waiting for some minutes for his host to notice this, the Hunter posed several leading questions. These also failed to bring Bob's attention to the strange regularity, and the alien finally gave, up and pointed it out. Then, of course, it was perfectly clear to the man, and he couldn't understand why he had failed to notice it before.

"Well, you see it now," said his symbiont. "Now let's find out if it was that way when Miss Teroa found it, or if it has become that way since." He left Bob with the problem of executing this simple request.

Logically, the man started with the most general questions possible.

"Mae, are you sure nothing has changed about this thing since you found it?"

"Not perfectly sure, but it definitely hasn't changed very much. Certainly no branches are broken. I admit I don't remember either the exact branch pattern or the arrangement of the patches of bare metal well enough to draw a picture, but if either of these has changed, I don't think it can be very much, either."

"The metal looks the same?"

"As far as I can remember. I'm afraid metal is just metal to me, unless it has a real color like copper or gold."

Bob saw no choice other than to get specific. "I was wondering about the scratches on the metal. They seem to be only on the bare parts-they never run out of sight under the coral. Of course there may be some scratches entirely under it, but it looks sort of as though someone had been making marks on the steel or whatever it is after the coral had grown."

"I see what you mean." Maeta nodded thoughtfully. "I don't remember really noticing the scratches before; maybe someone has been at it. I doubt it, though. The case it's been on is pretty high for young children to reach, and I don't think an adult would spoil it that way." Maeta, like Jenny, had not taken the college option, and for a brief moment Bob was startled by her naivety. He made no comment, however, even to the Hunter.

They moved around the table, examining the object from all sides. If any bit of the engraving was hidden at all, it was completelyhidden, as Bob had said. This, the Hunter feltsure, could not possibly be a matter of chance; andfrom the near despair of that morning, when Bob had awakened with the joint pains, the Hunter suddenly felt happier than he had in two Earth years. Perhapsthat was why he made a mistake.

"Bob," he said. There can't be any doubt. It can't

be an accident. Those areas were uncovered carefully, usingacid, to let someone read the engraving, and only my own people could either have expected to find anything to read or have counted on understanding it after it was uncovered!"

It was a forgivable mistake-not the logic, which was perfectly sound, but the failure to see the results of the remark. After all, Bob had seemed to be taking the situation very calmly-unbelievably calmly. If the young man's physical condition had been normal, the Hunter might have been able to spot the emotional tension of his host; but since the alien himself was handling, more or less directly, most of the hormone systems which emotion tends to affect, he had failed to do so. Bob's reaction took both of them by surprise.

"Then they are here!" he exclaimed happily-aloud. Jenny understood, naturally. Maeta, just as naturally, didn't, and was understandably surprised.

"Who is here?" she asked. "You mean you recognize the sort of ship this came from? That doesn't prove anything-I found this years ago, remember."

Bob covered fairly well, but not perfectly. "That's true," he admitted. "I wasn't thinking for the moment. Can you remember just when that was? You told us pretty well where."

The young woman was silent for some time, the rest watching with varying degrees of patience.

"Let's see," she said slowly at last. "The library was finished early in '51-I remember because I started to work here after school, as soon as it opened, and my first working day was my sixteenth birthday. I'd had this thing quite a while then. A year? No, longer. I never went out in the Haerehaere very often-the first time I was only twelve, and that was the year you came home so early and stayed so long, and when Charlie got his first ship job."

Bob nodded encouragingly, but managed to keep quiet this time. The year he had "stayed so long" was

the one in which the Hunter's first problem had been solved. Maeta went on.

"It must have been some time in March, either '48 or '49-oh, I remember. I'd been taking care of your sister a lot, and she was walking then, so it must have been March of '49, a little over five years ago."

"Good. Beautiful. Thanks a lot."

"So they, whoever they are, may have been here then, but they don't have to be here now," finished Maeta.

But Bob and the Hunter were sure they knew better.

"Bob, have you time to give us some help?"

The Hunter and his host were both startled. They were still standing around, the table which bore the generator case, but there had been several minutes of silence. Everyone had been pursuing his or her own line of thought, some of which had led pretty far from Ell. Maeta's question had not been an interruption, however, since neither Bob nor the Hunter had found a really promising line of thought to follow.

"I guess so," Bob answered. "What is it?"

"Those books you brought back have been brought to the library, and we have to catalog and shelve them. Can you help with the sorting? I'll recognize subjects all right; but we like to have some estimate of scope and difficulty. You've read them-I suppose."

"For the most part," Bob grinned. "All right, I might as well. Jenny, you want to stay and help?"

"No, thanks, I'm not at home in college books, and might feel lost-at least, I wouldn't be much help. I'll go ask Mr. Tavake that question we didn't get around to yesterday."

"All right, good idea." Bob read nothing between the lines of her refusal to stay. "Will you be home afterward? I think it's time we talked things over with your father. The next part of the job won't be easy even if Tavake comes through."

Jenny hesitated a moment; the Hunter assumed, she had made other plans and was weighing their importance. Bob gave no thought to the pause.

"All right," she finally said. "I'll see you-when? A couple of hours, Mae?"