'They do that all right.' He pulled his horse a little ahead of me, ending the conversation, and we rode on in silence. I kept raising my hand to remove the sweat that was falling into my eyes. I was not used to criss-crossing London like this. The heat was baking the rubbish in the streets, releasing all its vile humours. Beneath my doublet my armpits were damp with sweat and my breeches felt as though they were stuck to Chancery's saddle. This was a trial for him too: he was finding it hard to keep up with Barak's mare. I resolved that in future we would travel by water when we could. It was all very well for Barak and his horse – each was a decade younger than Chancery and me.

BY THE TIME we arrived back at Chancery Lane the sun was low. I told Joan to fetch us some food. In my parlour I dropped gratefully into my armchair; Barak collected some cushions together and sprawled inelegantly on the floor.

'Well, where are we now?' he asked. 'This day's nearly done. Then only ten more.'

'We've had more new leads than answers so far. But that's what I'd expect at the start of an investigation as complicated as this. We must visit that whore. And I think the goodwife is still holding something back. Is your man Smith staying with her?'

'Till otherwise instructed.' He retrieved his orange and sucked it noisily. 'I told you she was a nasty old crow.'

'It's something to do with the apparatus. I don't think they kept it the house.'

'Then where?'

'I don't know. Some warehouse? But there was nothing about any other property among their papers.'

'You looked?'

'Yes.'

I took the bottle from my pocket and handed it carefully to Barak. 'There was a pool of this stuff on the floor. It's almost colourless, has no smell, but if you taste it you get a kick like a mule.'

He unstoppered the bottle and sniffed the contents carefully, then put a little on his fingers. He touched it to his tongue and made a grimace, as I had. 'Jesu, you're right!' he said. 'It's not Greek Fire, though. I told you, that had a fearsome stink.'

I took the bottle back, stoppered it and shook it gently, watching the colourless liquid swirl within. 'I want to take this to Guy.'

'So long as you're careful what you tell him.'

'God's wounds, how many times do I have to tell you I will be?'

'I'll come with you.'

'As you will.'

'What exactly did you get out of the two lawyers?'

'Marchamount and Bealknap both insist they were just middlemen. I'm not sure about Bealknap. He's involved with Richard Rich in some way, though I don't know whether it relates to Greek Fire. Incidentally, he has dealings with foreign merchants, says he represents them in negotiations with the Custom House. I saw some papers on his desk. Lord Cromwell will have access to the records of trade. Could someone in his office check them? I've too little time.'

Barak nodded. 'I'll send a note. I've been trying to remember where I've seen that arsehole Bealknap's face before, but it hasn't come to me. It was a long time ago, I'm sure.'

There was a knock and Joan entered with a tray. She clucked at the dusty state of our clothes and I asked her to lay out new ones upstairs. I winced at a spasm from my back as I bent to pour some beer.

'You shouldn't overtire yourself, sir,' she said.

'I'll be all right when I've had some rest.'

As she left us, we both took welcome draughts of beer.

'The Duke of Norfolk was in a confident mood today,' I said. 'Baiting reformers at the lunch. A friend of mine baited him back, he'll be in trouble now.'

'I thought lawyers were all reformers.'

'Not all. And they'll turn to follow the wind, just like everyone else in London, if Cromwell falls. From fear and hope of advancement.'

'We've so little time,' Barak said. 'Are you sure we need to go to Barry's with that librarian tomorrow? I agree you need to talk to him, but you could see him at his chantry.'

'No. I need to see the roots of this, to go back to where it all started. Tomorrow we'll go to Barry's, then to see Guy and to the whorehouse in Southwark to see if that girl has anything to say. I've my interview with the Wentworths as well.' I sighed.

'Ten days.' He shook his head.

'Barak,' I said, 'I may be a melancholy man, but you have all the marks of a sanguine humour. You would rush at things too much if it was left to you.'

'We need this finished. And don't forget how we were followed yesterday,' he added gloomily. 'We might be in danger too.'

'I know that only too well.' I stood up. 'And now I am going to look at more of those old papers.'

I left him and went up to my bedroom, reflecting how I had felt afraid when I walked alone to the Inn earlier. I had to admit that when I was out I felt safer with Barak, the man of the streets, around. But I wished I did not have the necessity.

NEXT MORNING, the thirty-first of May, was hotter than ever. Again we left early on horseback; the way to St Bartholomew's lay due northward so we could not use the river. The sun was still low in the sky, turning a bank of thin cloud on the horizon to bright pink. Barak had gone out again the evening before and I had been asleep when he returned. At breakfast he seemed in a surly mood; perhaps he had a hangover, or a girl had sent him packing and dented his vanity. I packed a couple of the alchemical books into the battered old leather satchel my father had given me when first I came to London. I wanted Guy to look at them later.

The City was coming to life after the Sunday rest; shutters and shelves clattered as the shopkeepers made ready for the new week, shifting beggars from their doorways with curses. The homeless ones stumbled into the street, faces red and chapped with constant exposure to the sun. One, a little girl, almost stumbled into Chancery.

'Careful there,' I called.

'Careful yourself, shitting hunchback bastard!' Furious eyes stared at me from a filthy face, and I recognized the girl who had caused the commotion at the baker's shop. I watched her limp away, dragging one leg. 'Poor creature,' I said. 'When people say that beggars lick the sweat from the true labourers' brows, I wonder if they think of waifs like that?'

'Ay.' Barak paused. 'Did you manage to ferret any more out of those old papers last night?'

'There is a lot about the Greek wars in those manuscripts. There was much trickery in them. Once, to deceive their opponents into thinking they had more troops than they did, Alexander tied torches to the tails of a flock of sheep. The Persians, looking at his camp at night, thought he had far more men than was true.'

Barak grunted. 'Sounds like balls. The sheep would have bolted. Anyway, what's that to do with our business?'

'The story stuck in my head for some reason. There is reference as well to some sort of liquid being used in Rome's wars in Babylonia. There are a few books on the Roman wars at Lincoln's Inn; I'll try to find them.'

'So long as it doesn't take too much time.'

'Did you write to Lord Cromwell about Bealknap and the customs?'

'Ay. And last night I tried to find some more about that man who followed us. No luck.'

'We haven't seen him again. Perhaps he's given up.'

'Maybe, but I'll keep my eyes open.'

We passed a dead mastiff in an alleyway, its bloated carcass stinking to heaven. Why did people flock to the City, I wondered, to the ratlike scrabble for subsistence that so often ended in begging on the streets? The lure of money, I supposed; hopes of scraping a living and dreams of becoming rich.

St Sepulchre's was one of a number of streets giving onto the wide open space of Smithfield. It was quiet this morning, for it was not one of the fair days when drovers brought hundreds of cattle in to market. To one side the hospital of St Bartholomew's stood silent and empty behind its high wall, an Augmentations guard at the gate. When the monastery went down the year before, the patients had been turned out to fend for themselves as best they could; talk of a new hospital paid for by subscriptions from the rich had come to nothing yet.