‘I appreciate it, John. It’s nice to be kept informed.’ There was a slight pause there, an invitation for Rebus to join Lauderdale’s ‘camp’. And after the pause: ‘Any progress on Professor Costello’s books?’

Rebus sighed. ‘No, sir.’

‘Oh well. Mustn’t keep you chatting then. Bye, John.’

‘Goodbye, sir.’ Rebus wiped his palm across his forehead. It was hot in here, like a dress rehearsal for the Calvinist hell.

The fan had been installed and turned on, and an hour or so later Doctor Curt provided the shit to toss at it.

‘Murder, yes,’ he said. ‘Almost definitely murder. I’ve discussed my findings with my colleagues, and we’re of a mind.’ And he went on to explain about froth and unclenched hands and diatoms. About problems of differentiating immersion from drowning. The deceased, a woman in her late twenties or early thirties, had imbibed a good deal of drink prior to death. But she had been dead before she’d hit the water, and the cause of death was probably a blow to the back of the head, carried out by a right-handed attacker (the blow itself having come from the right of the head).

But who was she? They had a photograph of the dead woman’s face, but it wasn’t exactly breakfast-time viewing. And though her description and a description of her clothes had been given out, nobody had been able to identify her. No identification on the body, no handbag or purse, nothing in her pockets . . .

‘Better search the area again, see if we can come up with a bag or a purse. She must have had something.’

‘And search the river, sir?’

‘A bit late for that probably, but yes, better give it a shot.’

‘The alcohol,’ Dr Curt was telling anyone who would listen, had ‘muddied the water, you see’, after which he smiled his slow smile. ‘And the fish had eaten their fill: fish fingers, fish feet, fish stomach . . .’

‘Yes, sir. I see, sir.’

All of which Rebus mercifully avoided. He had once made the mistake of making a sicker pun than Dr Curt, and as a result found himself in the doctor’s favour. One day, he knew, Holmes would make a better pun yet, and then Curt would have himself a new pupil and confidant . . . So, skirting around the doctor, Rebus made for Lauderdale’s office. Lauderdale himself was just getting off the phone. When he saw Rebus, he turned stony. Rebus could guess why.

‘I just sent someone round to Glass’s bedsit.’

‘And he’s gone,’ Rebus added.

‘Yes,’ Lauderdale said, his hand still on the receiver. ‘Leaving little or nothing behind him.’

‘Should be easy enough to pick him up, sir.’

‘Get on to it, will you, John? He must still be in the city. What is it? – an hour since he left here. Probably somewhere in the Granton area.’

‘We’ll get out there right away, sir,’ said Rebus, glad of this excuse for a little action.