Other engines displayed different solutions to the challenge of multiplying fire. Here was a great wheel set horizontally, mounted with cannon spread radially like the petals of a daisy, which turned and spat fire when each gun was brought to the right position.
And now, shaking itself to life with a series of crashing explosions, here came the most spectacular machine of all. It was the testudo, named by the brothers after the famous formation of the Roman legions. It was a great shell of steel, immensely heavy, tough enough to withstand a direct hit from any of the defenders' petty weapons. Cannon fired from ports in all the forward angles, and as it advanced it shook and shuddered, smoke billowing from its ports from the internal detonations that drove it forward. It was unstoppable, inhuman. The testudo simply crushed a crumbling stone wall beneath its great hidden wheels, and the defenders, their shot and bolts and arrows simply bouncing off the mighty shell, fled, probably terrified out of their wits by the noise alone.
From James's elevated vantage he could smell nothing of the battle; he could hear little save the distant crump of explosions and the shouting of men like birds' cries, sounds drowned by the hiss of the wind in his wings, and his own rapid breathing. It was like watching a battle played out with toys, he thought – distant and abstract enough to quash his own conscience, and to allow him to savour the exhilaration of his extraordinary flight over these engines of carnage.
Now it was time for James himself to deliver the finishing blow. He tugged on guide ropes so that his wooden bird swooped to a line that led straight to the mock fortress. He glanced to his left to the observers' canvas pavilion, to see if Bartolomeo Colon and the rest were watching him. He saw Grace in a bright purple gown. He grinned, and the wind was cold on his teeth, and his heart beat even faster.
He banked over the fortress. As his huge shadow crossed the village some of the defenders ran, their superstitious fear overwhelming them, though they knew it was James. Now he pulled at the leather tags at his belt, one, two, three, four. The metal eggs were released and fell straight down, their bird-like shapes cutting through the air, the fins at their backs stabilising their fall.
All four landed in the heart of the fortress, splashing fire as they hit. The noise of the explosions hit him, and a sudden updraught of hot air pushed him higher. He whooped with an unreasonable joy. James was a man of peace, but he was young enough to relish the sheer exhilaration of such a complicated and dangerous game.
And as the fires bloomed he thought of Grace, Grace pushed down before him, Grace begging for his forgiveness – begging him to stop.
He looked over at the pavilion. Grace and the others were standing and pointing – not towards James and the fortress, but east. James craned his neck to see that way.
Something was wrong.
XVIII
'The testudo,' Ferron said weakly, 'is astounding. Devilish!'
'Not the devil,' Grace said smoothly. 'It is all the work of man, his imagination divinely inspired.'
'But how is it possible for such a weight even to drag itself over the earth? There must be a herd of horses in there.' He cupped his ears in gloved hands. 'And the noise-'
'Not horses. Bacon's black powder.' And, sitting beside Ferron in the wooden viewing stand, she tried to explain how the gunpowder had been harnessed into an engine. 'There are a series of pistons. When the gunpowder charge explodes above each piston, air is forced out of a chamber of iron, and the piston is dragged up, as a man inhaling may draw a feather into his mouth. That motion is translated into a turning of the great wheels, by a complicated mechanism James could no doubt describe for you. And so the steel beast travels forward, powered by a beating heart, each pulse a detonation that could kill ten men…'
While Bartolomeo Colon stared, fascinated, it seemed to be too much for Ferron. He held his hands over his ears, flinching from each new explosion. 'Devilish,' he repeated. 'Devilish.'
She tried to distract him with the manufactory's new sort of arquebus; one of them was set up on display before them. 'Then consider this, brother. The old sort of hand gun, as Isabel is deploying against the Moors even now, is slow to reload, and unreliable to fire, for you must apply a flame to the powder that propels the shot. Now we have a new sort of gun – based, again, on the designs in the Codex – which is fired not by flame but by a spark.' She showed him how, when a trigger was pulled, a hammer slammed a bit of flint against a steel plate; the resulting sparks were funnelled into a chamber to ignite the gunpowder.
Ferron was distracted by the glistening mechanism as she operated it. 'I see,' he said. 'I see.'
'It is still difficult to reload – we will work on that – but the reliability is so much improved, the weapon is so much safer, that it will be as if we have double the number of soldiers in the field. And furthermore-'
'What,' Ferron said, pointing, 'is that?'
It was a woman – young, scrawny, dirty. Grace had no idea who she was. She was running. She fled towards the battlefield. Grace could not have imagined a more unexpected sight.
And now monks followed her, grimy, blinking in the light. They too ran towards the noise and smoke of the field, not pursuing the girl, just running. But one of them called over his shoulder to the spectators in the viewing stand. 'The manufactory! Get away, my lady – the manufactory!'
'Dear God,' Ferron said.
Grace was bewildered, unable to understand what was happening. 'I think-'
The explosion was a roar, all around her. She was thrown forward onto the ground, helpless as a doll.
From the air, James saw fire erupt from the ground, a line of searing fountains. Monks and novices squirmed out of hatches like moles emerging from their holes, and ran off. James understood immediately. The fire was breaking out of the ground through the air vents of the underground manufactory. The explosions must have come from within the compound. It was the store of gunpowder, it could only be that. Some accidental spark had ignited it – or perhaps, he thought suddenly, it had been deliberate.
James had to concentrate on his own flight. His mechanical bird was dipping towards the ground. He had only a few heartbeats left in which he could control his descent. He scanned the ground anxiously, looking for a clear space to land.
But a fresh set of explosions broke out over the location of the main manufactory, distracting him, and James saw bones hurled into the sky. The gunpowder must have broken open a plague pit. It was an extraordinary, unnatural sight to see those bones go flying up into the air and then fall back, a grotesque parody of the Day of Judgement.
XIX
Harry, with Abdul and Geoffrey, had been watching the display from a distance, with appalled fascination. The wooden bird in the sky especially was an awful, unnatural sight.
But when the fires began to erupt from the ground they all knew something had gone badly wrong. Abandoning all attempts to conceal themselves, they ran towards the party coming from the viewing pavilion.
They met the others not far from the entrance to the manufactory. The explosions had stopped now, but smoke still poured from the ground. No more monks clambered out of the hatches, and Harry wondered how many had died that day.
Diego Ferron was unmistakable, a tall, pale cleric. He was holding a woman by her hair, a wretched, skinny girl in a grubby white gown. Beside Ferron and his captive was Grace Bigod. She was a hard woman of nearly fifty, her face smeared with soot and twisted in fury. It was the first time Harry had met this remote cousin.