'Tell me we checked the salt,' he said.
'That's the pepper, sir,' said Carrot helpfully.
'Salt! Mustard! Vinegar! Pepper!' said Vimes. 'We didn't check all the food and then let his lordship tip poison on to suit his taste, did we? Arsenic's a metal. Can't you get ... metal salts? Tell me we asked ourselves that. We aren't that stupid, are we?'
'I'll check directly,' said Carrot. He looked around desperately. 'I'll just put the tray down - '
'Not yet,' said Vimes. 'I've been here before. We don't rush off shouting Give me a towel! just because we've had one idea. Let's keep looking, shall we? The spoon. What's it made of?'
'Good point. I'll check the cutlery, sir.'
'Now we're cooking with charcoal! What's he been drinking?'
'Boiled water, sir. We've tested the water. And I checked the glasses.'
'Good. So... we've got the tray and you put the tray in the dumbwaiter and then what?'
'The men in the kitchen haul on the ropes and it goes up to the sixth floor.'
'No stops?'
Carrot looked blank.
'It goes up six floors,' said Vimes. 'It's just a shaft with a big box in it that can be pulled up and down, isn't it? I'll bet there's a door into it on every floor.'
'Some of the floors are hardly used these days, sir - '
'Even better for our poisoner, hmm? He just stands there, bold as you like, and waits for the tray to come by, right? We don't know that the meal which arrives is the one that left, do we?'
'Brilliant, sir!'
'It happens at night, I'll swear,' said Vimes. 'He's chipper in the evenings and out like a light next morning. What time is his supper sent up?'
'While he's poorly, around six o'clock, sir,' said Carrot. 'It's got dark by then. Then he gets on with his writing.'
'Right. We've got a lot to do. Come on.'
The Patrician was sitting up in bed reading when Vimes entered. 'Ah, Vimes,' he said.
'Your supper will be up shortly, my lord,' said Vimes. 'And can I once again say that our job would be a lot easier if you let us move you out of the palace?'
'I'm sure it would be,' said Lord Vetinari.
There was a rattle from the dumbwaiter. Vimes walked across and opened the doors.
There was a dwarf in the box. He had a knife between his teeth and an axe in each hand, and was glowering with ferocious concentration.
'Good heavens,' said Vetinari weakly. 'I hope at least they've included some mustard.'
'Any problems, Constable?' said Vimes.
'Nofe, fir,' said the dwarf, unfolding himself and removing the knife. 'Very dull all the way up, sir. There was other doors and they all looked pretty unused, but I nailed 'em up anyway like Captain Carrot said, sir.'
'Well done. Down you go.'
Vimes shut the doors. There was more rattling as the dwarf began his descent.
'Every detail covered, eh, Vimes?'