Iron Winter

must be thousands of people in this one line, perhaps tens of thousands.

He walked back along the line towards its head. Every so often the waiting horde would move forward in a great rippling movement that spread along the line, and people jostled, making sure their neighbours didn’t try to jump a space. There were always fights somewhere, and soldiers would leap in with clubs raised to sort it out. Whatever it was these people were waiting for, they needed it badly.

The line ended at a simple table, manned by two officers and heavily guarded by a circle of troops. They backed onto a kind of storehouse built into the wall itself. The soldiers made a note of each supplicant’s name on a paper scroll, and then a bundle was handed over, wrapped in paper. The supplicant would hurry away with nods of obeisance and gratitude.

‘Bread,’ Uzzia murmured in his ear.

Avatak glanced around, surprised she’d found him. ‘Bread? That’s all?’

‘A daily hand-out from the Khan. And they send grain from the city stores to the provinces too. Apparently they have been feeding twenty thousand people from the city alone this way. But the granaries are emptying and every day the dole is cut down a little more. Of course the soldiers are always well fed. We need to get back inside the city.’

‘Why?’

‘A messenger found me. There’s been an explosion at the palace.’

‘There’s been a what?’

She grinned. ‘That rascal Pyxeas. You can’t leave him alone for a heartbeat, can you?’

They were brought to another corner of the palace, a smaller laboratory. Here another elaborate experimental apparatus had been set up, on a lesser scale — stands and tubes and flasks and pipes, mirrors, small oil heaters. But this equipment had been scattered around the room. The carpet was scorched, the paint on the wall blistered. One servant seemed to have been injured, a weeping woman, and a doctor was tending to her burned arm. Soldiers stood around, looking shocked, dismayed, as well they might, Avatak supposed. The explosion, deep inside the home of the Khan himself, must have made them fear assassins, and, worse, the punishment they would receive if any harm came to the Khan or his family.

And here was Pyxeas, a blissful smile on a soot-stained face, the fringe of white hair around his scalp vertical, his robe smeared black. Bolghai stood behind him, equally begrimed, rather more shamefaced. ‘Avatak!’ Pyxeas cried. ‘I hope you enjoyed your walk. You missed a bit of fun.’

‘I can see that. What were you making here — eruptors?’

‘Nothing of the sort! Though I can see you might have difficulty working it all out given that it’s lying in pieces everywhere. . Where is the gas tube, Bolghai?’

‘Over there,’ said the Mongol. ‘And there. Oh, and there’s a bit stuck in the ceiling, I think.’

As the philosophers and their servants gathered the fragments of the broken apparatus, gradually Avatak pieced together what Bolghai had been attempting here.

‘What controls our weather?’ Pyxeas asked. ‘The sun, whose position in the sky as determined by astronomical considerations fixes the amount of heat delivered to the world — and the air, through which that heat must pass. But how does the sun’s heat pass through the air? How much of it is blocked — and how much trapped, as the thinnest linen blanket will trap some of the warmth of the body? That’s what this apparatus seeks to determine.’

The core of it had been a long brass tube, held horizontally. One end of this was heated, either by reflected sunlight or an oil lamp. At the far end of the tube was a thin, upright glass flask containing oil; by seeing how the oil expanded and climbed up its flask you could tell how much heat was passed through the tube — or rather, through whatever was trapped inside.

‘Can you see?’ Pyxeas said, holding up a fragment of smashed-open tube. ‘The ends are sealed with rock salt, which passes heat without diminution. The tube can be evacuated altogether, emptied of any kind of air, or it can be blocked with metal plugs, so that virtually no heat passes. Thus we have a maximum and a minimum for the heat transfer. Then we can fill the tube with, well, whatever we like — ordinary air, fixed air, water vapour. And we can see how the various components of the air trap the heat differently.’

‘I think I see. And the conclusions?’

‘That the fixed air, even a trace of it, makes a very efficient blanket for the trapping of heat. Very efficient indeed.’

Uzzia was scowling. ‘Bits of gas in a tube, mirrors and flames — how did you manage to make all this blow up?’

‘That took some doing,’ Pyxeas admitted ruefully. ‘And on my first day here too. But — patience, my dear. Philosophical understanding grows as a child learns to walk, with one uncertain step at a time. Of course all these results are preliminary and need to be confirmed, which we can begin to do once we get this apparatus rebuilt. Where is that craftsman of yours, Bolghai? Got something better to do, has he? And can’t we get these wretched soldiers out of here?’

43

High on the Wall, fisherman Crimm didn’t want to get too close to the balcony rail. The day was clear and bitterly cold, and the balcony was thick with ice, slick and slippery and bright in the low winter sun that hung in the southern sky, shining straight in his eyes. Plenty of opportunity to go tumbling off this balcony, to go skimming down the length of the incongruously cheerful banners that had been unfurled down the face of the Wall, and to smash his head open on the heaps of rubble at the foot, thus getting himself killed before the day’s action even started.

Ayto, though, wasn’t troubled. He rested easy on the rail, arms folded, mittened hands stuck under his armpits, staring south, oblivious of the drop below. He waited calmly at Crimm’s side, just as they had so often faced a storm at sea about to fall on the Sabet.

Now there was motion on the ice-bound land, far to the south, black specks crawling under a clear blue sky. People approaching the Wall.

Ayto murmured, ‘Is it them?’

‘Not sure.’

‘They are coming up the Way, straight to Etxelur. .’

Despite the obvious approach there was no call yet from the lookouts on the Wall parapet. Crimm wasn’t surprised. You didn’t last long at sea without sharp eyes, and the lookouts would do no better than a couple of fishermen, stranded since the loss of the Sabet. And of course there was always a chance of snow blindness on a bright day like this. To the south, as he looked out now, all of Northland to the far horizon was locked under a covering of ice and heaped-up snow, a panorama in white and black and blue and streaks of silver-grey where ice lay on deeper water. Across a world locked in ice the Wall itself strode, its tremendous face frost-cracked and strewn with icicles, yet standing against the winter as it had defied the sea for millennia. But perhaps it had all been for nothing, Crimm thought, for those whom the Wall had been built to protect were now preparing to attack it.

Ayto stirred. ‘It’s them all right. It’s not just more nestspills. You can see the organisation. They’re moving as a pack. And there’s metal glinting.’

‘Weapons.’

‘That would be my guess,’ Ayto said drily.

The lookouts woke up at last. Calls went up all along the Wall, from the roof scouts, across the balconies and galleries. People emerged to take their places at the rails, grim-faced, scared, shivering with the biting cold, and yet determined to play their part in saving the Wall.

Ywa joined the fishermen, coming out from the inner Wall to the balcony. The Annid of Annids’ quilted coat was open to the waist so that her bronze chest plate could be seen, a very ancient and battle-scarred relic. She allowed herself one glance at Crimm. He took her arm, squeezed it, out of sight of the rest. They rarely had time alone nowadays.

‘So they come,’ she said. ‘The scheme is working. They’ve ignored the other Districts and are heading straight for us, for Etxelur.’