The rushing noise died away. Blup.

Leonard peered cautiously over the bench and smiled broadly. 'Ali! Happily, we appear to have achieved coffee,' he said.

'Coffee?'

Leonard walked over to the table and pulled a small lever on the device. A light . brown foam cascaded into a waiting cup with a noise like a clogged drain.

'Different coffee,' he said. 'Very fast coffee. I rather think you will like it. I'm calling this the Very-Fast-Coffee machine.'

'And that's today's invention, is it?' said Vetinari.

'Well, yes. It would have been a scale model of a device for reaching the moon and other celestial bodies, but I was thirsty.'

'How fortunate.' Lord Vetinari carefully removed an experimental pedal-powered shoepolishing machine from a chair and sat down. 'And I've brought you some more little... messages.'

Leonard almost clapped his hands. 'Oh, good! And I've finished the other ones you gave me last night.'

Lord Vetinari carefully removed a moustache of frothy coffee from his upper lip. 'I beg your...? All of them? You broke the cyphers on all those messages from Uberwald?'

'Oh, they were quite easy after I'd finished the new device,' said Leonard, rummaging through the piles of paper on a bench and handing the Patrician several closely written sheets. 'But once you realize that there are only a limited number of birth dates a person can have, and that people do tend to think the same way, cyphers are really not very hard.'

'You mentioned a new device?' said the Patrician.

'Oh, yes. The... thingy. It's all very crude at the moment, but it suffices for these simple codes.'

Leonard pulled a sheet off something vaguely rectangular. It seemed to Vetinari to be all wooden wheels and long thin spars which, he saw when he moved closer, were inscribed thickly with letters and numbers. A number of the wheels were not round but oval or heartshaped or some other curious curve. When Leonard turned a handle, the whole thing moved with a complex oiliness quite disquieting in something merely mechanical.

'And what are you calling it?'

'Oh, you know me and names, my lord. I think of it as the Engine for the Neutralizing of Information by the Generation of Miasmic Alphabets, but I appreciate that it does not exactly roll off the tongue. Er...'

'Yes, Leonard?'

'Er... it's not... wrong, is it—reading other people's messages?'

Vetinari sighed. The worried man in front of him, who was so considerate of life that he carefully dusted around spiders, had once invented a device that fired lead pellets with tremendous speed and force. He thought it would be useful against dangerous animals. He'd designed a thing that could destroy whole mountains. He thought it would be useful in the mining industries. Here was a man who, in his tea break, would doodle an instrument for unthinkable mass destruction in the blank spaces around an exquisite drawing of the fragile beauty of the human smile. With a list of numbered parts. And if you taxed him with it he'd say: ah, but such a thing would make war completely impossible, you see? Because no one would dare use it.

Leonard brightened up as a thought apparently struck him. 'But, on the other hand, the more we know about one another the more we will learn to understand. Now, you asked me to construct some more cyphers for you. I'm sorry, my lord, but I must have misunderstood your requirements. What was wrong with the first ones I did?'

Vetinari sighed. 'I'm afraid they were unbreakable, Leonard.'

'But surely—'

'It's hard to explain,' said Vetinari, aware that what to him were the lucid waters of politics were so much mud to Leonard. 'These new ones you have are... merely devilishly difficult?'

'You specified fiendishly, sir,' said Leonard, looking worried.

'Oh, yes.'

'There does not appear to be a common standard for fiends, my lord, but I did some research in the more accessible occult texts and I believe these cyphers will be considered "difficult" by more than 96 per cent of fiends.'

'Good.'

'They may perhaps verge on the diabolically difficult in places—'

'That is not a problem. I shall use them forthwith.'

Leonard still seemed to have something on his mind. 'It would be so easy to make them archdemonically diff—'

'But these will suffice, Leonard,' said Vetinari.

'My lord,' Leonard almost wailed, 'I really cannot guarantee that sufficiently clever people will be unable to read your messages!'

'Good.'

'But, my lord, they will know what you are thinking!'

Vetinari patted him on the shoulder. 'No, Leonard. They will merely know what is in my messages.'

'I really do not understand, my lord.'

'No, but on the other hand I cannot make exploding coffee. What would the world be like if we were all alike?'

Leonard's face clouded for a moment. 'I'm not sure,' he said, 'but if you'd like me to work on the problem I may be able to devise a—'

'It was merely a figure of speech, Leonard.'

Vetinari shook his head ruefully. It often seemed to him that Leonard, who had pushed intellect into hitherto undiscovered uplands, had discovered there large and specialized pockets of stupidity. What would be the point of cyphering messages that very clever enemies couldn't break? You'd end up not knowing what they thought you thought they were thinking...

'There was one rather strange message from Uberwald, my lord,' said Leonard. 'Yesterday morning.'

'Strange?'

'It was not cyphered.'

'Not at all? I thought everyone used codes.'

'Oh, the sender and recipient are code names, but the message is quite plain. It was a request for information about Commander Vimes, of whom you have often spoken.'

Lord Vetinari went quite still.

'The return message was mostly clear, too. A certain amount of... gossip.'

'All about Vimes? Yesterday morning? Before I—?'

'My lord?'

'Tell me,' said the Patrician. 'This message from Uberwald. It yields no clue at all to the sender?'

Sometimes, like a ray of light through clouds, Leonard could be quite perceptive. 'You think you might know the originator, my lord?'

'Oh, in my younger days I spent some time in Uberwald,' said the Patrician. 'In those days rich young men from Ankh-Morpork used to go on what we called the Grand Sneer, visiting farflung countries and cities in order to see at first hand how inferior they were. Or so it seemed, at any rate. Oh, yes. I spent some time in Uberwald.'

It was not often that Leonard of Quirm paid attention to what people around him were doing, but he saw the faraway look in Lord Vetinari's eye.

'You have fond memories, my lord?' he ventured.

'Hmm? Oh, she was a very... unusual lady but, alas, rather older than me,' said Vetinari.

'Much older, I have to say. But it was a long time ago. Life teaches us its small lessons and we move on.' There was that distant look again. 'Well, well, well...'

'And no doubt the lady is now dead,' said Leonard. He was not much good at this sort of conversation.

'Oh, I very much doubt that,' said Vetinari. 'I have no doubt she thrives.' He smiled. The world was becoming more... interesting. 'Tell me, Leonard,' he said. 'Has it ever occurred to you that one day wars will be fought with brains?'

Leonard picked up his coffee cup. 'Oh dear. Won't that be rather messy?' he said.

Vetinari sighed again. 'Not perhaps as messy as the other sort,' he said, trying the coffee. It really was rather good.

The ducal coach rolled past the last of the outlying buildings and on to the vast, flat Sto Plains. Cheery and Detritus had tactfully decided to ride on the top for the morning, leaving the Duke and Duchess alone inside. Skimmer was indulging in some uneasy class solidarity and riding with the servants for a while.