With surprising delicacy, his pudgy fingers maneuvered the Bell, feeling for one best spot. He adjusted it, steadying it daintily. Then, letting the Bell swing free, he brought down the thick end of the bone spoon and stroked the Bell softly.

It was as though a million harps h d sounded a mile away. It swelled and faded and returned. It came from no particular direction. It sounded inside the head, incredibly sweet and pathetic and tremulous all at once.

It died away lingeringly and both men were silent for a full minute.

Dr Urth said, ‘Not bad, eh?’ and with a flick of his hand set the Bell to swinging on its wire.

Davenport stirred restlessly. ‘Careful! Don’t break it.’ The fragility of a good Singing Bell was proverbial.

Dr Urth said, ‘Geologists say the Bells are only pressure-hardened pumice, enclosing a vacuum in which small beads of rock rattle freely. That’s what they say. But it’that’s all it is, why can’t we reproduce one? Now a flawless Bell would make this one sound like a child’s harmonica.’

‘Exactly,’ said Davenport, ‘and there aren’t a dozen people on Earth who own a flawless one, and there are a hundred people and institutions who would buy one at any price, no questions asked. A supply of Bells would be worth murder.’

The extraterrologist turned to Davenport and pushed his spectacles back on his inconsequential nose with a stubby forefinger. ‘I haven’t forgotten your murder case. Please go on.’

‘That can be done in a sentence. I know the identity of the murderer.’

They had returned to the chairs in the library and Dr Urth clasped his hands over his ample abdomen. ‘Indeed? Then surely you have no problem, Inspector.’

‘Knowing and proving are not the same, Dr Urth. Unfortunately he has no alibi.’

‘You mean, unfortunately he has, don’t you?’

‘I mean what I say. If he had an alibi, I could crack it somehow, because it would be a false one. If there were witnesses who claimed they had seen him on Earth at the time of the murd r, their stories could be broken down. If he had documentary proof, 1t could be exposed as a forgery or some sort of trickery. Unfortunately he has none of it.’

‘What does he have?’

Carefully Inspector Davenport described the Peyton estate in Colorado. He concluded, ‘He has spent every August there in the strictest isolation. Even the T.B.I. would have to testify to that. Any jury would have to presume that he was on his estate this August as well, unless we could present definite proof that he was on the Moon.’

‘What makes you think he was on the Moon? Perhaps he is innocent.’

‘No!’ Davenport was almost violent. ‘For fifteen years I’ve been trying to collect sufficient evidence against him and I’ve never succeeded. But I can smell a Peyton crime now. I tell you that no one but Peyton, n? one on Earth, would have the impudence or, for that matter, the practical business contacts to attempt disposal of smuggled Singing Bells. He is known to be an expert space pilot. He is known to have had contact with the murdered man, though admittedly not for some months. Unfortunately none of that is proof.’

Dr Urth said, ‘Wouldn’t it be simple to use the psychoprobe, now that its use has been legalized?’

Davenport scowled, and the scar on his cheek turned livid. ‘Have you read the Konski-Hiakawa law, Dr Urth?’

‘No.’

‘I think no one has. The right to mental privacy, the government says, is fundamental. All right, but what follows? The man who is psychoprobed and proves innocent of the cri_me for which he was psychoprobed is entitled to as much compensation as ?e can persuade the courts to give him. In a recent case a bank cashier was a:-1arded twenty-five thousand dollars for having been psychoprobed on mac urate suspicion of theft. It seems that the circumstantial evidence wh1c? seemed to point to theft actually pointed to a small spot f adult ry. His claim that he lost his job, was threatened by the husband m question and put in bodily fear, and finally was held up to ridicule and contumely because a news-strip man had learned the results of the probe held good in court.’

‘I can see the man’s point.’

‘So can we all. That’s the trouble. One more item to remember: Any man who has been psychoprobed once for any reason can never be psychoprobed again for any reason. No one man, the law says, shall be placed in mental jeopardy twice in his lifetime.’

‘Inconvenient.’

‘Exactly. In the two years since the psychoprobe has been legitimized, I couldn’t count the number of crooks and chiselers who’ve tried to get themselves psychoprobed for purse-snatching so that they could play the rackets safely afterward. So you see the Department will not allow Peyton to be psychoprobed until they have firm evidence of his guilt. Not legal evidence, maybe, but evidence that is strong enough to convince my boss. The worst of it, Dr Urth, is that if we come into court without a psychoprobe record, we can’t win. In a case as serious as murder, not to have used the psychoprobe is proof enough to the dumbest juror that the prosecution isn’t sure of its ground.’

‘Now what do you want of me?’

‘Proof that he was on the Moon sometime in August. It’s got to be done quickly. I can’t hold him on suspicion much longer. And if news of the murder gets out, the world press will blow up like an asteroid striking Jupiter’s atmosphere. A glamorous crime, you know – first murder on the Moon.’

‘Exactly when was the mm;der committed?’ asked Urth, in a sudden transition to brisk cross-examination.

‘August twenty-seventh.’

‘And the arrest was made when?’

‘Yesterday, August thirtieth.’

‘Then if Peyton were the murderer, he would have had time to return to Earth.’

‘Barely. Just barely.’ Davenport’s lips thinned. ‘If I had been a day sooner- If I had found his place empty—’

‘And how long do you suppose the two, the murdered man and the murderer, were on the Moon altogether?’

‘Judging by the ground covered by the footprints, a number of days. A week, at the minimum.’

‘Has the ship they used been located?’

‘No, and it probably never will. About ten hours ago, the University of Denver reported a rise in background radioactivity beginning day before yesterday at 6 P.M. and persisting for a number of hours. It’s an easy thing, Dr Urth, to set a ship’s controls so as to allow it to blast off without crew and blow up, fifty miles high, in a micropile short.’

‘If I had been Peyton,’ said Dr Urth thoughtfully, ‘I would have killed the man on board ship and blown up corpse and ship together.’

‘You don’t know Peyton,’ said Davenport grimly. ‘He enjoys his victories over the law. He values them. Leaving the corpse on the Moon is his challenge to us.’

‘I see.’ Dr Urth patted his stomach with a rotary motion and said, ‘Well, there is a chance.’

‘That you’ll be able to prove he was on the Moon?’

‘That I’ll be able to give you my opinion.’ ‘Now?’

‘The sooner the better. If, of course, I get a chance to interview Mr Peyton.’

‘That can be arranged. I have a non-grav jet waiting. We can be in Washington in twenty minutes.’

But a look of the deepest alarm passed over the plump extraterrologist’s face. He rose to his feet and pattered away from the T.B.I. agent toward the duskiest comer of the cluttered room.

‘No!’

‘What’s wrong, Dr Urth?’

‘I won’t use a non-grav jet. I don’t believe in them.’

Davenport stared confusedly at Dr Urth. He stammered, ‘Would you prefer a monorail?’

Dr Urth snapped, ‘I mistrust all forms of transportation. I don’t believe in them. Except walking. I don’t mind walking.’ He was suddenly eager. ‘Couldn’t you bring Mr Peyton to this city, somewhere within walking distance? To City Hall, perhaps? I’ve often walked to City Hall.’