He found himself moving closer to Davenport, who seemed insensible to the unpleasantness of the situation.

Davenport said in a low voice, 'He'll be here in a moment, sir.'

'Is it always like this?' asked Ashley.

'Always. He never leaves this place, as far as I know, except to trot across the campus and attend his classes.'

'Gentlemen! Gentlemen!' came a reedy, tenor voice. 'I am so glad to see you. It is good of you to come.'

A round figure of a man bustled in from another room, shedding shadow and emerging into the light.

He beamed at them, adjusting round, thick-lensed glasses upward so that he might look through them. As his fingers moved away, the glasses slipped downward at once to a precarious perch upon the round nubbin of his snub nose. 'I am Wendell Urth,' he said.

The scraggly gray Van Dyke on his pudgy, round chin did not in the least add to the dignity which the smiling face and the stubby ellipsoidal torso so noticeably lacked.

'Gentlemen! It is good of you to come,' Urth repeated, as he jerked himself backward into a chair from which his legs dangled with the toes of his shoes a full inch above the floor. 'Mr. Davenport remembers, perhaps, that it is a matter of-uh-some importance to me to remain here. I do not like to travel, except to walk, of course, and a walk across the campus is quite enough for me.'

Ashley looked baffled as he remained standing, and Urth stared at him with a growing bafflement of his own. He pulled a handkerchief out and wiped his glasses, then replaced them, and said, 'Oh, I see the difficulty. You want chairs. Yes. Well, just take some. If there are things on them, just push them off. Push them off. Sit down, please.'

Davenport removed the books from one chair and placed them carefully on the floor. He pushed the chair toward Ashley. Then he took a human skull off a second chair and placed the skull even more carefully on Urth's desk. Its mandible, insecurely wired, unhinged as he transferred it, and it sat there with jaw askew.

'Never mind,' said Urth, affably, 'it will not hurt. Now tell me what is on your mind, gentlemen ?'

Davenport waited a moment for Ashley to speak, then, rather gladly, took over. 'Dr. Urth, do you remember a student of yours named Jennings? Karl Jennings?'

Urth's smile vanished momentarily with the effort of recall. His somewhat protuberant eyes blinked. 'No,' he said at last. 'Not at the moment.'

'A geology major. He took your extraterrology course some years ago. I have his photograph here, if that will help.'

Urth studied the photograph handed him with nearsighted concentration, but still looked doubtful.

Davenport drove on. 'He left a cryptic message which is the key to a matter of great importance. We have so far failed to interpret it satisfactorily, but this much we see-it indicates we are to come to you.'

'Indeed? How interesting! For what purpose are you to come to me?'

'Presumably for your advice on interpreting the message.'

'May I see it?'

Silently Ashely passed the slip of paper to Wendell Urth. The extraterrologist looked at it casually, turned it over, and stared for a moment at the blank back. He said, 'Where does it say to ask me?'

Ashley looked startled, but Davenport forestalled him by saying, The arrow pointing to the symbol of the Earth. It seems clear.'

'It is clearly an arrow pointing to the symbol for the planet Earth. I suppose it might literally mean "go to the Earth" if this were found on some other world.'

'It was found on the Moon, Dr. Urth, and it could, I sup pose mean that. However, the reference to you seemed clear once we realized that Jennings had been a student of yours.'

'He took a course in extraterrology here at the University?'

That's right.'

'In what year, Mr. Davenport?'

'In '18.'

'Ah. The puzzle is solved.'

'You mean the significance of the message?' said Davenport.

'No, no. The message has no meaning to me. I mean the puzzle of why it is that I did not remember him, for I remember him now. He was a very quiet fellow, anxious, shy, self-effacing-not at all the sort of person anyone would remember. Without this'-and he tapped the message-'I might never have remembered him.'

'Why does the card change things?' asked Davenport.

The reference to me is a play on words. Earth-Urth. Not very subtle, of course, but that is Jennings. His unattainable delight was the pun. My only clear memory of him is his occasional attempts to perpetrate puns. I enjoy puns, I adore puns, but Jennings-yes, I remember him well now-was atrocious at it. Either that, or distressingly obvious at it, as in this case. He lacked all talent for puns, yet craved them so much---'

Ashley suddenly broke in. This message consists entirely of a kind of wordplay, Dr. Urth. At least, we believe so, and that fits in with what you say.'

'Ah!' Urth adjusted his glasses and peered through them once more at the card and the symbols it carried. He pursed his plump lips, then said cheerfully, 'I make nothing of it.'

'In that case---' began Ashley, his hands balling into fists.

'But if you tell me what it's all about,' Urth went on, 'then perhaps it might mean something.'

Davenport said quickly, 'May I, sir? I am confident that this man can be relied on-and it may help.'

'Go ahead,' muttered Ashley. 'At this point, what can it hurt?'

Davenport condensed the tale, giving it in crisp, telegraphic sentences, while Urth listened carefully, moving his stubby fingers over the shining milk-white desktop as though he were sweeping up invisible cigar ashes. Toward the end of the recital, he hitched up his legs and sat with them crossed like an amiable Buddha.

When Davenport was done, Urth thought a moment, then said, 'Do you happen to have a transcript of the conversation reconstructed by Ferrant?'

'We do,' said Davenport. 'Would you like to see it?'

'Please.'

Urth placed the strip of microfilm in a scanner and worked his way rapidly through it, his lips moving unintelligibly at some points. Then he tapped the reproduction of the cryptic message. 'And this, you say, is the key to the entire matter? The crucial clue?'

'We think it is, Dr. Urth.'

'But it is not the original. It is a reproduction.'

'That is correct.'

The original has gone with this man, Ferrant, and you believe it to be in the hands of the Ultras.'

'Quite possibly.'

Urth shook his head and looked troubled. 'Everyone knows my sympathies are not with the Ultras. I would fight them by all means, so I don't want to seem to be hanging back, but-what is there to say that this mind-affecting object exists at all ? You have only the ravings of a psychotic and your dubious deductions from the reproduction of a mysterious set of marks that may mean nothing at all.'

'Yes, Dr. Urth, but we can't take chances.'

'How certain are you that this copy is accurate? What if the original has something on it that this lacks, something that makes the message quite clear, something without which the message must remain impenetrable?'

'We are certain the copy is accurate.'

'What about the reverse side? There is nothing on the back of this reproduction. What about the reverse of the original?'

'The agent who made the reproduction tells us that the back of the original was blank.'

'Men can make mistakes.'

'We have no reason to think he did, and we must work on At least until such time as the original is regained.'

'Then you assure me,' said Urth, 'that any interpretation to be made of this message must be made on the basis of exactly what one sees here.'

'We think so. We are virtually certain,' said Davenport with a sense of ebbing confidence.

Urth continued to look troubled. He said, 'Why not leave the instrument where it is? If neither group finds it, so much the better. I disapprove of any tampering with minds and would not contribute to making it possible.'

Davenport placed a restraining hand on Ashley's arm sensing the other was about to speak. Davenport said, 'Let me put it to you. Dr. Urth, that the mind-tampering aspect is not the whole of the Device. Suppose an Earth expedition to a distant primitive planet had dropped an old-fashioned radio there, and suppose the native population had discovered electric current had been not yet developed the vacuum tube.

The population might discover that if the radio was hooked up to a current, certain glass objects within it would grow warm and would glow, but of course they would receive no intelligible sound, merely, at best, some buzzes and crackles. However, if they dropped the radio into a bathtub while it was plugged in, a person in that tub might be electrocuted. Should the people of this hypothetical planet therefore conclude that the device they were studying was designed solely for the purpose of tilling people?'

'I see your analogy.' said Urth. 'You think that the mind tampering property is merely an incidental function of the Device?'

'I'm sure of it,' said Davenport earnestly. 'If we can puzzle out its real purpose, earthly technology may leap ahead centuries.'

Then you agree with Jennings when he said'-here Urth consulted the microfilm-' "It might be the key to-who knows what? It might be the clue to an unimaginable scientific revolution."'

'Exactly!'

'And yet the mind-tampering aspect is there and is infinitely dangerous. Whatever the radio's purpose, it does electrocute.'

'Which is why we can't let the Ultras get it.'

'Or the government either, perhaps ?'

'But I must point out that there is a reasonable limit to caution. Consider that men have always held danger in their hands. The first flint knife in the old Stone Age; the first wooden club before that could kill. They could be used to bend weaker men to the will of stronger ones under threat of force and that, too, is a form of mind-tampering. What counts, Dr. Urth, is not the Device itself, however dangerous it may be in the abstract, but the intentions of the men who make use of the Device. The Ultras have the declared intention of killing off more than 99-9 per cent of humanity. The government, whatever the faults of the men composing it, would have no such intention.'

'What would the government intend?'

'A scientific study of the Device. Even the mind-tampering aspect itself could yield infinite good. Put to enlightened use, it could educate us concerning the physical basis of mental function. We might learn to correct mental disorders or cure the Ultras. Mankind might learn to develop greater intelligence generally.'

'How can I believe that such idealism will be put into practice?'

'I believe so. Consider that you face a possible turn to evil by the government if you help us, but you risk the certain and declared evil purpose of the Ultras if you don't.'

Urth nodded thoughtfully. 'Perhaps you're right. And yet I have a favor to ask of you. I have a niece who is, I believe quite fond of me. She is constantly upset over the fact that I steadfastly refuse to indulge in the lunacy of travel. She states that she will not rest content until someday I accompany her to Europe or North Carolina- or some other outlandish place---'

Ashley leaned forward earnestly, brushing Davenport's restraining gesture to one side. 'Dr. Urth, if you help us find the Device and if it can be made to work, then I assure you that we will be glad to help you free yourself of your phobia against travel and make it possible for you to go with your niece anywhere you wish.'

Urth's bulging eyes widened and he seemed to shrink within himself. For a moment he looked wildly about as though he were already trapped. 'No.'' he gasped. 'Not at all! Never!'

His voice dropped to an earnest, hoarse whisper. 'Let me plain the nature of my fee. If I help you, if you retrieve the Device and learn its use, if the fact of my help becomes public, then my niece will be on the government like a fury. She is a terribly headstrong and shrill-voiced woman who will raise public subscriptions and organize demonstrations. She will stop at nothing. And yet you must not give in to her. You must not! You must resist all pressures. I wish to be left alone exactly as I am now. That is my absolute and minimum fee.'

Ashley flushed. 'Yes, of course, since that is your wish.'

'I have your word?'

'You have my word.'

'Please remember. I rely on you too, Mr. Davenport.'

'It will be as you wish,' soothed Davenport. 'And now, I presume, you can interpret the items?'

The items?' asked Urth, seeming to focus his attention with difficulty on the card. 'You mean these markings, XY2 and so on?'

'Yes. What do they mean ?'

'I don't know. Your interpretations are as good as any, I suppose.'

Ashley exploded. 'Do you mean that all this talk about helping us is nonsense ? What was this maundering about a fee, then?'

Wendell Urth looked confused and taken aback. 'I would like to help you.'

'But you don't know what these items mean.'

'I-I don't. But I know what this message means.'

'You do?' cried Davenport.

'Of course. It's meaning is transparent. I suspected it halfway through your story. And I was sure of it once I read the reconstruction of the conversations between Strauss and Jennings. You would understand it yourself, gentlemen, if you would only stop to think.'

'See here,' said Ashley in exasperation, 'you said you don't know what the items mean.'

'I don't. I said I know what the message means.'

'What is the message if it is not the items ? Is it the paper, for Heaven's sake?'

'Yes, in a way.'

'You mean invisible ink or something like that?'

'No! Why is it so hard for you to understand, when you yourself stand on the brink?'

Davenport leaned toward Ashley and said in a low voice, 'Sir, will you let me handle it, please ?'

Ashley snorted, then said in a stifled manner, 'Go ahead.'