Iron Winter

You can feel it dragging into your lungs, you can use pumps to evacuate it from a chamber — we all felt its lack up on the roof of the world. And the air is made up of several component parts, which can be separated with sufficient ingenuity. This was first achieved by Northlander scholars. We know there is vital air, an air full of energy, which we suspect is the agent that supports combustion — and indeed the slower fire that burns in our bodies to sustain life. And then there is fixed air. This was first identified by a scholar at Etxelur called Cleomedes, of Greek descent, who studied the burning of charcoal in a closed vessel.’

Bolghai said, ‘The scholars of Cathay have long shared their knowledge with Northland, a tradition I have sought, in my time, to maintain, or rather revive. I with my party was the first to travel to Northland after the conquests of the Great Khans. And, given the importance of the air to the weather which shapes all our destinies, as Pyxeas points out, we have continued its study here. Although Cathay scholars are perhaps of a more practical bent than those of Northland.’

Pyxeas sighed. ‘True, true, but the first Wall-builders would cringe to hear you say it. That’s the legacy of Pythagoras and his Greeks, who could be a bit contemplative.’

Bolghai gestured at his apparatus. ‘We have found ways to measure the presence and concentration of fixed air more precisely. For instance here, you see, the air from this chamber is fed through lime dissolved in water; it precipitates a kind of chalk whose weight we can determine. . The details are unimportant.’

‘Not to me, they’re not!’ thundered Pyxeas. ‘I want to examine every tube and valve, every seal and measuring gauge. Excellent experimental design,’ he said now, walking around the boxes. ‘Can you see it, Avatak? Why these empty boxes, for instance?’

That was easy; Avatak had seen similar set-ups in Pyxeas’ own studies. ‘They are for comparison. A horse in this box, not in that box that’s otherwise the same; you can subtract one from the other to see what difference the horse makes.’

‘Exactly!’

Bolghai said, ‘Of course the emissions and absorptions vary depending on the plant or beast enclosed, and indeed on its conditions — if the horse is agitated or not, resting or exercising, for instance. All these things we can study.’

Uzzia asked, ‘Who is the man in the box?’

Bolghai seemed puzzled by the question. 'Who? Why — he is the subject. I sent specifications to the slavers regarding size and weight and general health. I hope to extend the studies to compare different ethnicities, ages, health conditions — sex, of course. I am not concerned with who.

‘What is most important is the conclusion. Which is this.’ With the air of a showman he walked them past the compartments containing the grass, the grain. ‘Vegetables, plants, trees — as they grow these things absorb the fixed gas from the air. But if they are burned they release that gas again. Whereas animals, from sheep to pigs to men, they release the fixed gas as they breathe. All of this in the processes of their lives, you see — it seems accurate, as you say, Pyxeas, to think of life as a kind of slow burning, animal life at least. Plants and animals, absorption and release-’

‘Yes, yes. And together they shape the atmosphere — and it shapes them. But to what end, what end? And how does this relate to the longwinter? For somehow it must. .’

‘Quite so,’ Bolghai said. ‘To explore that I am also running studies of the physical properties of fixed air. Perhaps that will offer some clues. But the properties are subtle, the apparatus unwieldy and preliminary. Nevertheless I have some first results. We can proceed to that when we’re done here.’

‘Good, good,’ Pyxeas murmured. The two scholars wandered off, talking, debating.

Servants stood by Uzzia and Avatak, heads bent, waiting for instructions.

‘I want to get out of here,’ whispered Avatak.

‘Yes. And I’ve got deals to do. We’ve delivered Pyxeas to his scholar; we’ve done our jobs for now. Let’s go.’

42

Uzzia wandered through Daidu, reacquainting herself with a city she’d visited once before. Avatak followed her, gradually finding his bearings.

Within its double walls the city was laid out like a board game played by giants, the rectangle of walls enclosing a grid-pattern of streets, with tidy blocks of houses and inns and manufactories, temples and schools, all on a tremendous scale. Avatak, a boy from a chaotic land of ice and water, even having visited Northland’s mighty Wall, felt utterly out of place in this vision of stone and geometry.

But the vision could be pleasing. You would turn a corner and come upon a park gleaming green in the late autumn sunshine, with animals apparently roaming loose: squirrels, ermine, deer, even stags. A river ran right through the city, and people walked its banks and crossed delicate bridges. The people were both Cathay and Mongol, the latter in their colourful silk tunics and coats. People spoke Mongol, or one of the tongues of Cathay, or a rapid language that Uzzia identified as Persian, a common tongue for the traders who came here.

Some of the grander folk went on horseback. The cultured Cathay folk seemed to flinch at seeing horses inside a city, but the Mongols’ bond with their animals was indissoluble. Avatak saw one man ride along under a canopy of gold, carried by bearers who had to run alongside. Uzzia said this was probably a baron, one of the Khan’s top generals, who would command a hundred thousand men or more.

In one place by the river Avatak saw a tower, four or five times taller than a man, with a small waterwheel at its side. On the top was a brass construction, a ring showing the constellations, models of sun and moon. It was a representation of the sky, driven by the waterwheel, like a tremendously expanded version of Pyxeas’ oracle. Perhaps the links between Cathay and Northland really were deep and ancient, Avatak thought.

Uzzia said she wanted to go out of the city proper and into the suburbs, where the livelier markets were to be found. So they made their way to the northern wall, heading for a gate. The gates themselves were huge, like fortresses built into the walls, each hosting hundreds of soldiers. Uzzia spoke in her cursory Mongol to the guards, ensuring they could get back in later, even without Pyxeas’ paiza in their pockets. Beyond the gate they had to pass through the city’s outer layer of defences, over a moat filled with brackish water and then to an outer wall. There seemed to be a whole army of soldiers in rough camps in the space between the walls, with heaps of weapons, herds of the Mongols’ stocky ponies. ‘Not so much a city,’ murmured Uzzia as they walked, ‘as a fortress, and designed by Kublai to be that way. Well, I suppose it is inevitable; Old Hattusa was a fortress-city too, another capital of conquerors.’

The suburb beyond the outer walls was a city in itself, but much more disorderly, crowded, with a pall of greasy smoke rising from a hundred fires. There was a steady stream of traffic through the gates, of pedestrians, horse riders, and carts drawn by bullocks and horses. Avatak noticed a line of people, men, women and children, all of them shabby-looking, strung out along the length of the outer wall, leading away from the gate. They were waiting for something handed out at the gate itself by a team of soldiers; more tough-looking troops patrolled the line, weapons ready, prepared for any trouble.

Uzzia, evidently feeling more at home in this bustling market town, plunged into its narrow alleys. The houses here were of mud or sod bricks, and roofed by turf or wood slats. There was business being done everywhere, in inns, stores selling food or clothes or spices or precious goods, and brothels with exotic whores, both female and male, beckoning from doorways. Uzzia soon found a tremendous central marketplace, crowded with stalls. Avatak was baffled by the masses of porcelain, silks, plums, watermelons, and a blizzard of paper money. But the marketplace backed onto a stockyard where animals, distressed and calling out, were being lined up in huge numbers for slaughter in the open air. Corpses dangled from hooks, and the cobbles were sticky with old blood. Avatak had gutted seals and flensed walruses; he was far from squeamish. But the sheer scale of this slaughter, however necessary to feed the hungry city, repelled him.

With a word to Uzzia, he turned away and began to walk back towards the gate. He was curious about the line of people at the wall. When he came to the line he backtracked, trying to find the end, but the line stretched all the way to the corner of the wall’s rectangular layout, and back down the next side, and on out of his sight. There