The equipment didn't help. She scrounged what she could from the guild, but a real alchemical laboratory should be full of the kind of glassware that looked as if it were produced during the Guild of Glassblowers All-Comers Hiccuping Contest. A proper alchemist did not have to run tests using as her beaker a mug with a picture of a teddy-bear on it, which Corporal Nobbs was probably going to be very upset about when he found it missing.

When she judged that the fumes had cleared she ventured back into her tiny room.

That was another thing. Her books on alchemy were marvellous objects, every page a work of the engraver's art, but they nowhere contained instructions like 'Be sure to open a window'. They did have instructions like 'Adde Aqua Quirmis to the Zinc untile Rising Gas Yse Vigorously Evolved', but never added 'Don't Doe Thys Atte Home' or even 'And Say Fare-thee-Welle to Thy Eyebrows'.

Anyway...

The glassware remained innocent of the brown-black sheen that, according to The Compound of Alchemic, would indicate arsenic in the sample. She'd tried every type of food and drink she could find in the palace pantries, and pressed into service every bottle and jar she could discover in the Watch House.

She tried one more time with what said on the packet it was Sample #2. Looked like a smear of cheese. Cheese? The various fumes thronging around her head were making her slow. She must have taken some cheese samples. She was pretty sure Sample #17 had been some Lancre Blue Vein, which had reacted vigorously with the acid, blown a small hole in the ceiling and covered half the work-bench with a dark green substance that was setting like tar.

She tested this one anyway.

A few minutes later she was scrabbling furiously through her notebook. The first sample she'd taken from the pantry (one portion of duck pate) was down here as Sample #3. What about #1 and #2? No, #1 had been the white clay from Misbegot Bridge, so what had been #2?

She found it.

But that couldn't be right!

She looked up at the glass tube. Metallic arsenic grinned back at her.

She'd retained a bit of the sample. She could test again, but... perhaps it would be better to tell someone...

She hurried along to the main office, where a troll was on duty. 'Where's Commander Vimes?'

The troll grinned. 'In der Gleam... Little-bottom. '

'Thank you.'

The troll turned back to address a worried-looking monk in a brown cassock. 'And?' he said.

'Best if he tells it himself,' said the monk. 'I only work on the next bench.' He put a small jar of dust on the desk. It had a bow tie around it.

'I want to complain most emphatically,' said the dust, in a shrill little voice. 'I was working there only five minutes and then splash. It's going to take days to get back into shape!'

'Working where?' said the troll.

'Nonesuch Ecclesiastical Supplies,' said the worried monk, helpfully.

'Holy water section,' said the vampire.

'You've found arsenic?' said Vimes.

'Yes, sir. Lots. The sample's full of it. But ...

'Well?'

Cheery looked at her feet. 'I tried my process again with a test sample, sir, and I'm sure I'm doing it right...'

'Good. What was it in?'

'That's just it, sir. It wasn't in anything from the palace. Because I'd got a bit confused and tested the stuffl found under Father Tubelcek's fingernails, sir.'

'What?

There was grease under his nails, sir, and I thought maybe it could've come from whoever attacked him. Off an apron or something... I've still got some left if you want a second opinion, sir. I wouldn't blame you.'

'Why would the old man be handling poison?' said Carrot.

'I thought he might have scratched the murderer,' said Cheery. 'You know ... put up a fight...'

'With the Arsenic Monster?' said Angua.

'Oh, gods,' said Vimes. 'What time is it?'

'Bingely bingely beep bong!'

'Oh, damn

'It's nine of the clock,' said the organizer, poking its head out of Vimes's pocket. ' I was unhappy because I had no shoes until I met a man with no feet. '

The Watchmen exchanged glances.

'What?' said Vimes, very carefully.

'People like it if I occasionally come up with a little aphorism or inspiring Thought For The Day,' said the imp.

'So how did you meet this man with no feet?' said Vimes.

'I didn't actually meet him,' said the imp. 'It was a general metaphorical statement.'

'Well, that's it, then,' said Vimes. 'If you'd met him you could have asked him if he had any boots he didn't have any use for.'

There was a squeak as he pushed the imp back into its box.

'There's more, sir,' said Cheery.

'Go on,' said Vimes wearily.

'And I had a careful look at the clay we found at the murder scene,' said Cheery. 'Igneous said it had a lot of grog in it - old powdered pottery. Well... I chipped a bit off Dorfl to compare and I can't be sure but I got the iconograph demon to paint really small details and ... I think there's some clay just like his in there. He's got a lot of iron oxide in his clay.'

Vimes sighed. All around them people were drinking alcohol. One drink would make it all so clear.

'Any of you know what any of this means?' he said.

Carrot and Angua shook their heads.

'Is it supposed to make sense if we know how all the pieces fit together?' Vimes demanded, raising his voice.

'Like pieces of a jigsaw, sir?' Cheery ventured.

'Yes!' said Vimes, so loudly that the room went quiet. 'Now all we need is the corner bit with the piece of sky and the leaves and it'll all be one big picture?'

'It's been a long day for all of us, sir,' said Carrot.

Vimes sagged. 'Okay,' he said. Tomorrow... I want you, Carrot, to check on the golems in the city. If they're up to something I want to know what it is. And you, Littlebottom... you look everywhere in the old man's house for more arsenic. I wish I could believe that you'll find any.'

Angua had volunteered to walk Littlebottom back to her lodgings. The dwarf was surprised that the men let her do this. After all, it'd mean that Angua would then have to walk on home by herself.

'Aren't you afraid?' Cheery said as they ambled through the damp clouds of fog.

'Nope.'

'But I imagine muggers and cut-throats would be out in a fog like this. And you said you lived in the Shades.'

'Oh, yes. But I haven't been bothered lately.'

'Ah, perhaps they're frightened of the uniform?'

'Possibly,' said Angua.

'Probably they've learned respect.'

'You may be right.'

'Er ... excuse me ... but are you and Captain Carrot... ?'

Angua waited politely.

'... Er...'

'Oh, yes,' said Angua, taking pity. 'We're er. But I stay at Mrs Cake's boarding house because you need your own space in a city like this.' And an understanding landlady sympathetic to those with special needs, she added to herself. Like doorhandles that a paw could operate, and a window left open on moonlit nights. 'You've got to have somewhere where you can be yourself. Anyway, the Watch House smells of socks.'

'I'm staying with my Uncle Armstrangler,' said Cheery. 'It's not very nice there. People talk about mining most of the time.'

'Don't you?'

'There's not a lot you can say about mining. I mine in my mine and what's mine is mine, ' said Cheery in a singsong voice. 'And then they go on about gold which, frankly, is a lot duller than people think.'

'I thought dwarfs loved gold,' said Angua.

They just say that to get it into bed.'

'Are you sure you're a dwarf? Sorry. That was a joke.'

'There must be more interesting things. Hair. Clothes. People.'

'Good grief. You mean girl talk?