Mandel, with an angry, incoherent cry, threw up the window and snatched it away. He shielded it in one cupped hand, staring out of hot and reddened eyes.

He said, "Wait here!"

There was nothing to say. When Mandel left, they sat down and stared stupidly at one another.

Mandel was back in twenty minutes. He said quietly (in a voice that gave the impression, somehow, that it was quiet only because its owner had passed far beyond the raving stage), "The corner in the crack wasn't overexposed. I could make out a few words. It is Villiers' paper.

The rest is ruined; nothing can be salvaged. It's gone."

"What next?" said Talliaferro.

Mandel shrugged wearily. "Right now, I don't care. Mass-transference is gone until someone as brilliant as Villiers works it out again. I shall work on it but I have no illusions as to my own capacity. With it gone, I suppose you three don't matter, guilty or not. What's the difference?" His whole body seemed to have loosened and sunk into despair.

But Talliaferro's voice grew hard. "Now, hold on. In your eyes, any of the three of us might be guilty. I, for instance. You are a big man in the field and you will never have a good word to say for me. The general idea may arise that I am incompetent or worse. I will not be ruined by the shadow of guilt. Now let's solve this thing."

"I am no detective," said Mandel wearily.

"Then call in the police, damn it."

Ryger said, "Wait a while, Tal. Are you implying that I'm guilty?"

"I'm saying that I'm innocent."

Kaunas raised his voice in fright. "It will mean the Psychic Probe for each of us. There may be mental damage-"

Mandel raised both arms high in the air. "Gentlemen! Gentlemen! Please! There is one thing we might do short of the police; and you are right, Dr. Talliaferro, it would be unfair to the innocent to leave this matter here."

They turned to him in various stages of hostility. Ryger said, "What do you suggest?"

"I have a friend named Wendell Urth. You may have heard of him, or you may not, but perhaps I can arrange to see him tonight."

"What if you can?" demanded Talliaferro. "Where does that get us?"

"He's an odd man," said Mandel hesitantly, "very odd. And very brilliant in his way. He has helped the police before this and he may be able to help us now."

Edward Talliaferro could not forbear staring at the room and its occupant with the greatest astonishment. It and he seemed to exist in isolation, and to be part of no recognizable world. The sounds of Earth were absent in this well-padded, windowless nest. The light and air of Earth had been blanked out in artificial illumination and conditioning.

It was a large room, dim and cluttered. They had picked their way across a littered floor to a couch from which book-films had been brusquely cleared and dumped to one side in a tangle.

The man who owned the room had a large, round face on a stumpy, round body. He moved quickly about on his short legs, jerking his head as he spoke until his thick glasses all but bounced off the thoroughly inconspicuous nubble that served as a nose. His thick-lidded, somewhat protuberant eyes gleamed in myopic good nature at them all, as he seated himself in his own chair-desk combination, lit directly by the one bright light hi the room.

"So good of you to come, gentlemen. Pray excuse the condition of my room." He waved stubby fingers in a wide-sweeping gesture. "I am engaged in cataloguing the many objects of extraterrological interest I have accumulated. It is a tremendous job. For instance-"

He dodged out of his seat and burrowed in a heap of objects beside the desk till he came up with a smoky-gray object, semi-translucent and roughly cylindrical. "This," he said, "is a Callistan object that may be a relic of intelligent nonhuman entities. It is not decided. Not more than a dozen have been discovered and this is the most perfect single specimen I know of."

He tossed it to one side and Talliaferro jumped. The plump man stared in his direction and said, "It's not breakable." He sat down again, clasped his pudgy fingers tightly over his abdomen and let them pump slowly in and out as he breathed. "And now what can I do for you?"

Hubert Mandel had carried through the introductions and Talliaferro was considering deeply. Surely it was a man named Wendell Urth who had written a recent book entitled Comparative Evolutionary Processes on Water-Oxygen Planets, and surely this could not be the man.

He said, "Are you the author of Comparative Evolutionary Processes, Dr. Urth?"

A beatific smile spread across Urth's face, "You've read it?"

"Well, no, I haven't, but-"

Urth's expression grew instantly censorious. "Then you should. Right now. Here, I have a copy-"

He bounced out of his chair again and Mandel cried at once, "Now wait, Urth, first things first. This is serious."

He virtually forced Urth back into his chair and began speaking rapidly as though to prevent any further side issues from erupting. He told the whole story with admirable word-economy.

Urth reddened slowly as he listened. He seized his glasses and shoved them higher up on his nose. "Mass-transference!" he cried.

"I saw it with my own eyes," said Mandel.

"And you never told me."

"I was sworn to secrecy. The man was-peculiar. I explained that."

Urth pounded the desk. "How could you allow such a discovery to remain the property of an eccentric, Mandel? The knowledge should have been forced from him by Psychic Probe, if necessary."

"It would have killed him," protested Mandel.

But Urth was rocking back and forth with his hands clasped tightly to his cheeks. "Mass-transference. The only way a decent, civilized man should travel. The only possible way. The only conceivable way. If I had known. If I could have been there. But the hotel is nearly thirty miles away."

Ryger, who listened with an expression of annoyance on his face, interposed, "I understand there's a flitter line direct to Convention Hall. It could have gotten you there in ten minutes."

Urth stiffened and looked at Ryger strangely. His cheeks bulged. He jumped to his feet and scurried out of the room.

Ryger said, "What the devil?"

Mandel muttered, "Damn it. I should have warned you."

"About what?"

"Dr. Urth doesn't travel on any sort of conveyance. It's a phobia. He moves about only on foot."

Kaunas blinked about in the dimness. "But he's an extraterrologist, isn't he? An expert on life forms of other planets?"

Talliaferro had risen and now stood before a Galactic Lens on a pedestal. He stared at the inner gleam of the star systems. He had never seen a Lens so large or so elaborate.

Mandel said, "He's an extraterrologist, yes, but he's never visited any of the planets on which he is expert and he never will. In thirty years, I doubt if he's ever been more than a mile from this room."

Ryger laughed.

Mandel flushed angrily. "You may find it funny, but I'd appreciate your being careful what you say when Dr. Urth comes back."

Urth sidled in a moment later. "My apologies, gentlemen," he said in a whisper. "And now let us approach our problem. Perhaps one of you wishes to confess."

Talliaferro's lips quirked sourly. This plump, self-imprisoned extraterrologist was scarcely formidable enough to force a confession from anyone. Fortunately, there would be no need of his detective talents, if any, after all.

Talliaferro said, "Dr. Urth, are you connected with the police?"

A certain smugness seemed to suffuse Urth's ruddy face. "I have no official connection, Dr. Talliaferro, but my unofficial relationships are very good indeed."

"In that case, I will give you some information which you can carry to the police."

Urth drew in his abdomen and hitched at his shirttail. It came free, and slowly he polished his glasses with it. When he was quite through and had perched them precariously On his nose once more, he said, "And what is that?"

"I will tell you who was present when Villiers died and who scanned his paper."

"You have solved the mystery?"

"I've thought about it all day. I think I've solved it." Talliaferro rather enjoyed the sensation he was creating.

"Well, then?"

Talliaferro took a deep breath. This was not going to be easy to do, though he had been planning it for hours. "The guilty man," he said, "is obviously Dr. Hubert Mandel."

Mandel stared at Talliaferro in sudden, hard-breathing indignation. "Look here, Doctor," he began, loudly, "if you have any basis for such a ridiculous-"

Urth's tenor voice soared above the interruption. "Let him talk, Hubert, let us hear him. You suspected him and there is no law that forbids him to suspect you."

Mandel fell angrily silent.

Talliaferro, not allowing his voice to falter, said, "It is more than just suspicion, Dr. Urth. The evidence is perfectly plain. Four of us knew about mass-transference, but only one of us, Dr. Mandel, had actually seen a demonstration. He knew it to be a fact. He knew a paper on the subject existed. We three knew only that Villiers was more or less unbalanced. Oh, we might have thought there was just a chance. We visited him at eleven, I think, just to check on that, though none of us actually said so-but he just acted crazier than ever."

"Check special knowledge and motive then on Dr. Mandel's side. Now, Dr. Urth, picture something else. Whoever it was who confronted Villiers at midnight, saw him collapse, and scanned his paper (let's keep him anonymous for a moment) must have been terribly startled to see Villiers apparently come to life again and to hear him talking into the telephone. Our criminal, in the panic of the moment, realized one thing: he must get rid of the one piece of incriminating material evidence.

"He had to get rid of the undeveloped film of the paper and he had to do it in such a way that it would be safe from discovery so that he might pick it up once more if he remained unsuspected. The outer window sill was ideal. Quickly he threw up Villiers' window, placed the strip of film outside, and left. Now, even if Villiers survived or if his telephoning brought results, it would be merely Villiers' word against his own and it would be easy to show that Villiers was unbalanced."