“Well . . . I’ve got all this stuff at home, all these birds and whatnot, but it’s a bit ridiculous. See, I’ve studied pigeons, robins, merlins, Jabber knows what else, but I’ve not yet seen a fucking garuda up close. So I’m going to go hunting. I’ve put it off, but I think the time’s come. I’m going to Spatters.” Isaac grimaced and let that sink in. He took another big bite. When he had swallowed, he looked at her from under his brows. “I don’t suppose . . . D’you want to come?”

Isaac, she signed immediately, don’t say that if you don’t mean it because I do want to come and I’ll say yes if you’re not careful. Even to Spatters.

“Look . . . I really . . . I do mean it. I’m serious. If you’re not working on your magnum opus this morning, come and knock about.” The conviction in his voice strengthened as he spoke. “Come on, you can be my mobile lab assistant. No, I know what you can do: you can be my heliotypist for the day. Bring your camera. You need a break.”

Isaac was getting bolder. He and Lin left the house together, without him displaying any signs of unease. They wandered a little way north-west along Shadrach Street, towards the Salacus Fields Station, but Isaac became impatient and hailed a cab on the way. The hirsute driver raised his eyebrows at Lin, but he kept any objections quiet. He inclined his head while he murmured to his horse, indicating Isaac and Lin inside.

“Where to, guv?” he asked.

“Spatters, please.” Isaac spoke rather grandly, as if making up in his tone of voice for his destination.

The driver turned to him incredulously. “You’ve got to be joking, squire. I ain’t going into Spatters. I’ll take you as far as Vaudois Hill, but that’s your lot. Ain’t worth my while. Down Spatters way, they’ll have the wheels off me cab while I’m still driving.”

“Fine, fine,” said Isaac irritably. “Just get us as close as you dare.”

As the rickety hansom cab rolled across the cobbles through Salacus Fields, Lin caught Isaac’s attention.

Is it really dangerous? she signed nervously.

Isaac glanced round, then answered her with signs himself. He was much slower and less fluent than her, but using signing he could be ruder to the cabdriver.

Well . . . just fuck poor. They’ll nick whatever’s going, but not especially violent. Arsehole here’s just cowardly. Reads too many . . . Isaac faltered and screwed up his face with concentration.

“Don’t know the sign,” he murmured. “Sensational. Reads too many sensational papers.” He sat back and looked out of the window at the skyline of Howl Barrow that wobbled unsteadily to his left.