The two old Adepti from the University of Adua scraped up like a pair of priests given a personal audience with God. The one called Denka was ghoul-pale and trembling. The one called Saurizin had a sheen of sweat across his wrinkled forehead which sprang back as fast as he could wipe it off.

‘Lord Bayaz.’ He tried to bow and grin at once and couldn’t manage either with any conviction. ‘I believe the weather has improved to the point where the devices can be tested.’

‘At last,’ snapped the Magus. ‘Then what are you waiting for, the Midwinter Festival?’

The two old men fled, Saurizin snarling fiercely at his colleague. They had an ill-tempered discussion with the dozen aproned engineers about the nearest tube, including a deal of arm-waving, pointing at the skies and reference to some brass instruments. Finally one produced a long torch, flames licking at the tarred end. The Adepti and their minions hurried away, squatting behind boxes and barrels, covering their ears. The torch-bearer advanced with all the enthusiasm of a condemned man to the scaffold, touched the brand at arm’s length to the top of the tube. A few sparks flew, a lick of smoke curled up, a faint pop and fizzle were heard.

Gorst frowned. ‘What is—’

There was a colossal explosion and he shrank to the ground, hands clasped over his head. He had heard nothing like it since the Siege of Adua, when the Gurkish put fire to a mine and blew a hundred strides of the walls to gravel. Guardsmen peeped terrified from behind their shields. Exhausted labourers scrambled gaping from their fires. Others struggled to control terrified horses, two of which had torn a rail free and were galloping away with it clattering behind them.

Gorst slowly, suspiciously, stood. Smoke was issuing gently from the end of one of the pipes, engineers swarming around it. Denka and Saurizin were arguing furiously with each other. What had been the effect of the device beyond the noise, Gorst had not the slightest idea.

‘Well.’ Bayaz stuck a finger in one ear and waggled it around. ‘They’re certainly loud enough.’

A faint rumble echoed over the valley. Something like thunder, though it seemed to Craw the weather was just clearing up.

‘You hear that?’ asked Splitfoot.

Craw could only shrug up at the sky. Plenty of cloud still, even if there were a few blue patches showing. ‘More rain, maybe.’

Dow had other things on his mind. ‘How are we doing at the Old Bridge?’

‘They came just after first light but Scale held ’em,’ said Splitfoot. ‘Drove ’em back across.’

‘They’ll be coming again, ’fore too long.’

‘Doubtless. Reckon he’ll hold?’

‘If he don’t we got a problem.’

‘Half his men are across the valley with Calder.’

Dow snorted. ‘Just the man I’d want at my back if I was fighting for my life.’

Splitfoot and a couple of the others chuckled.

There was a right way of doing things, far as Craw was concerned, and it didn’t include letting men laugh at your friends behind their backs, however laughable they may be. ‘That lad might surprise you,’ he said.