The Escapement

7

After an uneventful ride, Ziani arrived back at Civitas Vadanis shortly before sunset and went straight to the factory. Daurenja was there, of course, in his office, sitting in his chair, checking through materials requisitions. It was a job Ziani particularly hated, and he usually made stupid, time-wasting mistakes. Daurenja always did them flawlessly in half the time.

"You're back," Daurenja said, jumping up out of the chair. "Excellent. Good trip?"

Ziani closed the distance but Daurenja didn't move. "What the hell were you playing at?" Ziani shouted, squeezing his voice to make it louder. "You must be out of your mind. I had to beg the duke not to have you strung up."

Daurenja looked back at him solemnly. "I know, he told me," he said. "I owe you my life. I promise you I won't ever forget-"

"Shut up, you bloody lunatic." Shouting at Daurenja was like trying to swat flies in the dark. "I've heard some stupid things in my time, but someone going absent without leave to join a battle is just perverse. What were you trying to achieve, for God's sake?"

He wanted to build up and maintain a good head of anger, to gain the advantage. But all the time Daurenja was watching him; bright, sharp eyes, missing nothing. "I've learned my lesson," was all he said, "and no harm done. But I'm sorry if I disappointed you. You know I have the deepest admiration-"

Ziani winced, as though he'd lashed out at Daurenja, missed and barked his knuckles on the wall. "Be quiet," he said. "And tell me what's been happening here while I've been away."

Immediately Daurenja changed, from humble penitent to invaluable assistant. "Steady progress," he said. "Shop seven have finished the torsion capstan bearings, I've got the night shift fettling and assembling the completed mechanisms. The lumber for the crossbars came in early, so shop five are shaping, planing and cutting tenons. Shop three, we found out what the glitch was with the rope-winding loom, so it ought to be up and running in time for the swing shift." He gulped down more air, like a frog swallowing a fly, then continued, "Shop two's standing by waiting for material for the stone-turning mill, so I took the liberty of putting them on preparing for a test of that theory of mine I mentioned a while back, coating the balls. You remember?"

Ziani frowned. "No."

"Ah." Daurenja's eyebrows flickered. "Well, the idea is, a smooth, uniformly round ball will fly faster and straighter than an irregular one, because it slips through the air easier. Turning the balls perfectly spherical takes too long with the men and machines we've got, so I thought, if we rough-cut the balls and then coat them with clay or, better still, lead, we can get much closer to a perfect sphere and save time in the process. I've arranged a test-firing from the prototype five-inch engine, noon tomorrow, if you can spare the time. I hope that's all right."

Good idea, Ziani thought; a very good idea, which I should've thought of myself. "Fine," he grunted. "If it works, we'll need to add another process line. Use the spare corner of shop eight, you can borrow time on the forge for melting the lead. There should be enough-"

"Eight hundredweight, in number nine shed," Daurenja interrupted promptly. "We got it in for making slingbolts for the staff-slings, but they got cancelled and we're stuck with it. Actually, I was wondering about casting round shot out of solid lead for the modified Type Three scorpions. It'd mean sparing a couple of the best masons to carve soapstone moulds, but it'd be one less calibre to turn, which'd save time in shop two. With your permission…"

"Yes, fine. Let me know how you get on." Ziani sat down in the chair. "Now, listen. I promised the duke we'd have sixty Type Two scorpions for him in six days. He wants to set up fixed artillery positions on the Lonazep road, in case they try and get it open again. Can we do that?"

Daurenja thought for a moment, a perfect study in concentration. "I believe we can," he said. "If you can let me have an extra two dozen unskilled for packing and loading. I'd rather not take skilled men off the lines."

"Use soldiers," Ziani said with a faint grin. "There's enough of them hanging about, and they must be good for something. Right. Anything else?"

Suddenly Daurenja smiled. "One other thing," he said. "You're not going to like it."

"Then what are you grinning for?"

The smile widened into a grin. "The prototype of the Class Six heavy bombard," he said. "They got it finished."

"About time."

Daurenja nodded. "The thing is," he said, "the project captain was so pleased at getting it done at last, he couldn't wait till you or I got back to test it, so he did it himself. Only," he went on, "he doesn't seem to have understood how the recoil dampers are supposed to work, because he didn't bother to tighten them right up before setting the thing off. As a result, when he pulled the lever…"

"Oh for crying out loud."

Daurenja nodded. "Exactly," he said. "The damper threads stripped, the cradle went right back against the stop, and so, of course, instead of shooting out at an optimum forty-five degrees, the ball flew straight up in the air." He paused. "According to the captain, it went up a good four hundred yards, which is very encouraging. But then, of course, it came straight down again. Nobody hurt, I'm delighted to say, but the machine's firewood."

Ziani was silent for a moment. "You know," he said, "I'm sorry I missed seeing that."

"Me too," Daurenja said. "I imagine it was quite a sight. Anyway, we'll have another prototype assembled by the morning. And at least we know the torsion spring's up to scratch. Four hundred yards straight up; that's better than I was expecting."

"Quite," Ziani said. "You'd better put the captain on report, though. Teach him not to play with things."

"Actually, I've already dealt with it," Daurenja said. "He was no good anyway."

Ziani froze. Daurenja was tidying up the papers on the desk, putting the stopper back in the ink bottle. "You dealt with it?"

Daurenja nodded. "I had him flogged and branded and discharged," he said. "There's a report in the personnel file. As a replacement, I was thinking, there's that Eremian in shop eight, he's showing a lot of promise. I'll send him up to see you when his shift ends, or I can see to it if you're busy."

Ziani let him go. It was easier; and, after all, the captain had been responsible for the destruction of a valuable piece of equipment…

(I'm afraid of him, Ziani thought. Every time I'm in the same room with him, I can't help watching him, following everything he does. I could've been rid of him so easily; Valens was furious, he didn't care about the volcano dust, but I said no, we need him. And we do. I do.)

It was dark, and the lamp was burning down; the flame struggled as it starved and died, flicking yellow light around the walls. Ziani let it go out. There was more oil in a bottle somewhere, but he couldn't be bothered. Besides, in the dark he could see more clearly.

He traced out the lines, as though drawing a sketch. For each function, a mechanism. For each process, an assembly of components working together within the constraints of a frame. He labelled them in his mind: Eremians, Vadani, Cure Hardy; Valens, Orsea, Ducas, Veatriz; an unwieldy, unsatisfactory but functional sub-array designated Psellus; a system of belts, gears and shafts to drive them all from the power source. A group of functions economically combined in the ingenious component Daurenja, which he hadn't designed himself but rather cannibalised from an existing, damaged machine. He considered issues of tolerance and stress, with particular reference to bearings and strength of materials. He thought briefly about the disgraced project captain, tied to a door, flogged bloody and burned with a white-hot iron; about the shot fired straight up in the air, because a part of the mechanism hadn't been properly understood.

I have no right to do this, he thought.

He got up, groped around in the dark, found the bottle of oil and refilled the lamp. He had a genuine Mezentine flint-and-wheel tinderbox, a Type Sixteen. The light burned away the shape of the machine, like a sheet of paper turning to ash.

They had no right. They were going to kill me; and all I want is what was mine anyway. The stories about heroes who came back;

Ducas understood. You can't run away, go somewhere else, settle down and get a job like nothing has happened. It's like tensing a spring and just leaving it cocked. The steel has a memory. It has no choice.

But he didn't really believe it; because of course they had the right. Abomination can't go unpunished, or the stone flies straight up and smashes the machine. Daurenja understood that (but in that case, why did he run off and play at being a hero, when he knew that offences must be punished? Simple; because he's the crime and the punishment all rolled into one, a complex assembly performing many functions simultaneously. Leave him out of it).

The stone flies straight up, and when it lands it smashes the machine that launched it. Well of course, Ziani thought, as he trimmed the wick. That's what it's supposed to do. No choice. Shop thirteen was making the drills.

Ziani had seen a picture in a book, fifteen years ago. It showed a machine like a battering ram on a wheeled chassis, but it wasn't for bashing. Brick, the book explained, crumbles when hammered but doesn't shatter like stone. To wreck a brick wall, the approved procedure is to drill in it a series of three-inch holes no more than eight inches apart. Before drilling the next hole, insert a log, three-inch diameter, steeped in tar or pitch. Light the log-ends; by the time you've withdrawn to a safe distance, the logs will have burned through, leaving the now-unsupported wall to collapse. The book had been written for builders and stonemasons needing to demolish old buildings, so of course the ordnance department had never heard of it. A friend of his who worked the same shift at the ordnance factory had won a copy of it in a game of knucklebones and sold it to him for two quarters.

To make drills, he'd sent for the Vadani foresters. They knew exactly where to find what he needed: a stand of oaks planted on a steep hillside and neglected, never thinned out, with the result that they'd grown tall, straight and spindly, fighting to get above the forest canopy into the light. Ziani specified trunks seventy feet long, twelve inches in diameter at the base, eight at the top where the branches started to spread out. He had them cut off six inches short of that point, so that the end-grain would be tangled with knots and pins, and therefore resistant to splitting. The trunks were rolled down the hill to the river and floated to Civitas Vadanis in rafts of ten. The derricks and cranes built into the outside wall of shop thirteen lifted them easily and laid them down on the shop's long central floor, where they were planed and dressed. The carriages were ash; simple rectangular frames, inside which the oak trunk lay on an extending trolley with a bed of rollers. A cat's cradle of ropes running in pulleys turned it, and into its end was fitted a flat steel drill-bit three inches wide. The carriage had its own roof, tiled and sloping so that anything the defenders chose to drop or pour on it from above would slide or dribble harmlessly off. There wasn't time to build a geared transmission to drive the wheels, so it'd need forty men to push it along and twelve more to work the windlass that turned the drill. Jobs for the Aram Chantat.

With Duke Valens' book under his arm and a small bundle of sketches in his hand, Ziani went to see the foreman of shop thirteen. Yes, they'd just finished making the drill bits the previous evening; as it happened, they were just about to start fitting them. Ziani told the foreman what he wanted done instead, pinned him down to a firm time estimate and promised him a dozen blacksmiths to do the additional work.

Blacksmiths were, of course, in desperately short supply, but Daurenja's personnel roster showed him a dozen men he could reassign with the bare minimum of disruption and chaos. The men reported to him in the empty lumber store at the back of shop nine. Its principal merit was a long, plain plastered wall, which he'd had whitewashed. By the time the men arrived, he'd already drawn out the diagrams on the wall with a stump of charcoal.

He explained what he wanted, with reference to the diagrams. The men stared at him as though he was mad. But he was getting used to that sort of thing.

"Fine," he said. "All right, how many of you know how to forge a ploughshare?"

Eleven hands went up; there is, of course, always one who never admits to knowing anything.

"That's all right, then," he said. "Basically, it's just a toy windmill with four ploughshares instead of sails, rotating round a hub with a spindle stuck in it. Now, anybody got any problems with that?"

If they did, they kept quiet about it, so Ziani dismissed them and sent a note round to the stores, requisitioning fifteen of the large sheets of quarter-inch steel armour-plate. The quartermaster would, of course, scream and yell like mad and swear blind there weren't that many sheets left, and if there were, they were already earmarked for shop sixteen and the armourers. Daurenja could sort all that out. No point keeping a dog and snarling yourself.

Other calls to make. By the time he'd finished, the day shift had gone and the night shift had started up. He felt tired, so that his eyes itched and his knees ached, but he had six hours completely free; and, more to the point, nobody was using the toolroom at the back of shop seven.

Forty-eight lamps, set up in four racks of twelve, lit the toolroom, which had no windows or skylight. Another borrowing from standard practice at the ordnance factory. Changes, even slight, in the angle of sunlight coming in through a window can distort the way the fine calibrations on a dial or handscrew stand out, which can in turn lead to error. A constant, controllable level of artificial light makes for consistent work.

In the middle of the room stood the Vadani alliance's one and only Type Twenty-Three engine lathe; seventy-two inches between centres, swinging twelve inches over the bed, back-geared, as specified, perfect. Sometimes he came here just to see it; other times, he couldn't bear to look at it. How it had found its way to Civitas Vadanis he had no idea. It was at least ninety years since the Mezentines had stopped exporting them, on the grounds that nobody outside the Republic could be trusted with the potential of such a perfect artefact. Judging by the serial number, this one was at least a hundred and fifty years old. At some point, a blasphemer had oiled the bed, a crime to which the grooves scored in it by particles of grit and swarf embedded in oily paste bore silent, grim witness. Ziani himself had turned new headstock bearings for it and replaced the saddle shims. Apart from that, it had suffered no violations beyond the usual gentle, even wear of long, respectful use. Ziani had heard stories about the temples of the ancient heathens, in which the god was believed to be present, sublimated in the eucharist. Until he'd come here, he hadn't really been able to understand what that was supposed to mean.

There was a simple block-and-tackle hoist on the far wall, and he used it to lift the length of steel bar into position. He'd chalked his initials and his personal requisition code on it just before he left, to make sure nobody interfered with it; the chances of getting another one were practically nonexistent. It was round stock, six-inch diameter, eight feet long, best hardening steel; he'd tested it himself on the edge of a grinding wheel, and the shower of fat orange sparks had confirmed it: nothing less than a section of overhead shaft from one of the Republic's own factories, and how it could possibly have found its way here, he couldn't begin to guess.

Very slowly and carefully, he guided it into place over the bed of the lathe. You and me, he thought; we shouldn't be here, but here we are, and we've got work to do.

He clamped it to the faceplate with cramps and dogs, set the tail-stock live centre in the dimple he'd already drilled in the other end, slacked off the winch and unbuckled the sling. Then, hardly daring to breathe in case the whole thing shook loose and wrecked the lathe, he let in the drive and watched it start to turn. A minute studying it by eye, then the necessary checks with gauges; it was set up straight and running true. He wound in the compound table and set the screw for a five-thousandth-of-an-inch cut.

Two cuts, two hours each; another two hours grinding, lapping and polishing. He'd been tired out before he started work. By the time he'd finished, winched the bar out of the machine and up on to its place in the long rack, he was in that rare but unmistakable state where exhaustion no longer matters. He was drawing his strength directly from the work, concentrating so intensely that he simply didn't have attention to spare for anything else. Dimly he heard the sound of voices; the swing shift taking off their coats and changing their boots on the other side of the toolroom door. He tried to chalk on the bar, but the surface was too smooth, so he wrote on the rack instead.

The last thing he did before he dragged himself back to his office and fell asleep in his chair was to scribble a note for Daurenja and give it to one of the messengers. As he handed it over, as his fingertips lost contact with it, he felt a dreadful surge of fear, and knew he was making a terrible mistake; as if he'd written out a death warrant, and carelessly put in his own name instead of the condemned man's.

The mandrel's ready, he'd written. We can start whenever you like. He woke up. The messenger was standing over him, looking worried. "He said to give it to you right away," the messenger said defensively. "Said it was very important."

The messenger's tone of voice made it unnecessary to ask who he was talking about. "All right," Ziani grumbled. "Give it here, thank you."

Daurenja's handwriting-neat, pointed, sloping at an exaggerated angle-across the bottom of the scrap of drawing paper Ziani had used for his note.

As soon as possible. Now. G.D.

Ziani groaned, reached for the top of the ink bottle, stabbed about in the ink like a woodpecker in a rotten tree, and scribbled:

Don't be bloody stupid. I've had a long day and I'm going to get some sleep. We'll start the forging an hour after sunset tomorrow. Get everything ready for then.

"No rush," he said, as the messenger took the paper from his hand. "Make the bastard wait."

Then he dragged himself to his feet, went outside on to the gallery, climbed the spiral stone staircase to the tower room where he slept, and went to bed. Much to his surprise, he slept well, and woke up in daylight. His room in the tower was circular, with one small, strangely shaped window about a foot off the floor. After a month or so of wild speculation, he'd got around to asking someone about it, and was told that the factory building had once been the keep of the citadel, before Valens' great-grandfather built the ducal palace on the other side of town. The upper gallery, where his office was, used to be the intermediate defensive ring, where archers shot down at besieging enemies and pushed scaling ladders away from the walls with long poles. The room he slept in, his informant added, was the watch platoon garderobe.

"I see," he'd said. "What the hell's a garderobe?" Basically, military terminology for a toilet; which explained, among other things, the position and shape of what he'd taken for a window. Boiling oil and molten lead weren't the only things you dropped on besiegers' heads, apparently.

He changed his shirt and trousers and put on a heavy-duty leather apron, and boots with steel toecaps, then went down to the gallery and along to the corner tower, where there was usually something to eat. Today, it was salt bacon, more salt than bacon, a basin of grey slop under a thick knobbly skin, and grey bread you could've sharpened axes on. He was hungry, but he couldn't bring himself to burst the skin on the grey slop. An earlier diner had left a hacksaw beside the bacon. It got the job done, eventually.

A little later, his mouth tasting uncomfortably of salt, he went to his office and attacked the paperwork for an hour, at the end of which his early-morning freshness had all gone. He felt blunt, like a knife misused for cutting lead, and he still had far too much to do.

The foreman of shop eleven rescued him in the nick of time; something about the bearings on the reciprocating saw, which nobody else was allowed to touch if it went wrong. Ziani smiled, abandoned the paperwork and spent a pleasant couple of hours in the small toolroom, turning up new bearings on the little toymakers' lathe he'd built himself. He stretched the job out a little, pretending to himself that a mirror finish was essential for the smooth running of the saw. Once upon a time, he thought, there was a man who worked in a factory rather like this one, only better; he checked tolerances and fought his way through paperwork, and when something broke he fixed it himself, because that was quicker and easier than explaining to someone else how to do it; he didn't like the administration much, and when he found an excuse to get away from it for an hour or so and spend time actually cutting and shaping metal, he used to wonder why the hell he'd ever wanted to be the foreman instead of an ordinary engineer; once upon a time, in a distant land, and also here, now, where the avenging hero had finally settled down, made new friends and got a job. The difference, the tolerance, the margin of error, was something you checked with a simple piece of metal, a yes/no gauge. If you put the gauge over the finished component and it fit, the piece was good. If not, scrap. Yes or no; no tolerance.

The bearing fitted perfectly, which was how it should be. After all, he thought, I do good work, and everything I make fits and does its job; which is why I can't be satisfied with sleeping in a toilet in a watchtower, while my wife and daughter think I'm dead or never coming home again. No fit; scrap.

The rest of the day passed rather too quickly. He knew the sun was setting when the light through the arrow slits in the wall of shop nine blazed a garish orange in the freshly cut steel of the catapult ratchets. An hour to go. He went back to the corner tower and ate some more of the grit-hard bread.

Then Daurenja came for him, like an executioner. There was a big covered space at the back of the factory. In the old days, they'd told him, it had been the castle mews, where the hawks and falcons were kept, a dark, quiet place, suitable for savage, neurotic creatures in captivity. Now it was just a shell with a high roof and no windows. On Daurenja's orders, they'd cut a hole in the roof for a flue, rising up out of a broad funnel-shaped canopy, hung by wires from the rafters. Directly under it they'd dug a wide, shallow pit, lined it with firebrick and run in two-inch-bore clay pipes to conduct the blast from four enormous double-action bellows. Surrounding the pit like a moat was a channel, six inches deep and three wide, filled with water. Against one wall lay a mountain of charcoal.

Two heavy A-shaped iron frames stood a little to the right of the pit, supporting the two ends of the tool-steel mandrel Ziani had turned on the lathe. Next to that, two five-hundredweight double-horned anvils, and lying on the floor around them buckets of water, mops, bundles of cloth, wide-mouthed pails of water, with whole fleeces stuffed in them to soak, iron cans and dippers fixed on the ends of long poles. Two dozen men in aprons stood by the far wall, looking nervous.

"I've already hardened and tempered the mandrel," he heard Daurenja say, and for a moment he couldn't think what he was talking about. "It's going to be tricky keeping the frames from burning through. We'll just have to make sure they're damped down all the time."

A table, liberated from somebody's kitchen. On it lay eight pairs of tongs, sixteen sledgehammers, a big stone pestle and mortar, clay jars, rolls of three-sixteenth iron wire, a clutter of small, commonplace tools, a tinderbox, two fire-rakes, four wire brushes. "I think we've got everything," Daurenja was saying, and Ziani realised he sounded worried, the first time ever. It reminds me of something, Ziani thought, and realised it was two things, not one: preparations for an execution, and the midwife getting the kitchen ready, the day Moritsa was born.

"Swage blocks," Ziani said. "You've forgotten the swage blocks."

Daurenja shook his head. "Over there," he said, pointing into the shadows. "It's so dark in here you can't see them. Look, will somebody get some lamps lit, for crying out loud?"

It'd have to be dark once they started, of course; they needed to be able to see the fine differences in the blinding white of iron at welding heat, and the soft glow of a single candle might be enough to deceive them. "Get the blocks over here by the hearth," Daurenja was telling someone. "And have the staves laid out in order, we don't want to be fooling about dry-fitting once we're up and running. And then you might as well get the fire lit. The sooner we start, the sooner we'll see."

Someone picked up the tinderbox, but Daurenja took it from him. They were laying kindling in the middle of the pit; first small dry twigs and hay, then thin splinters of scrap planed wood stacked in a cone. Daurenja turned the tinderbox handle, blew on it, swore, called for more dried moss and shavings (Ziani smiled; he always had trouble getting a fire going himself). Someone leaned over his shoulder, offering to help, and was pushed out of the way. A little curl of smoke from the box. Daurenja took a long stride towards the pit and dumped the smouldering rubbish out of the box into the hole in the top of the stack of kindling. One of the bellows wheezed gently. An orange glow swelled and burst, like over-ripe fruit, into flames.

Two men started shovelling charcoal, sprinkling it slowly on to the fire as the second bellows started up. Apparently satisfied, Daurenja turned his back on the fire-pit and shouted something Ziani couldn't catch over the huff and roar of the bellows. Four men dragged a long wooden box out of the shadows, and two of them stooped and lifted out an iron plate, bending their knees and straightening up under the weight. The plate was five feet long, about a handspan wide, two inches thick. They laid it down on the table and stepped back, as Daurenja darted forward to examine the edges.

"Bloody rust," he shouted. "I thought I told you to keep the staves dry." He was scrubbing the edges with a small chunk of brick. "Got to keep the edges clean or the welds won't take." Someone handed him a clay pot, flux mixed with water to the consistency of thick porridge. He scooped out a thick blob with his finger, examined it and started smearing it on the freshly scrubbed edge.

"In the fire," he snapped; two men clamped heavy tongs on the plate, locking the handles shut with rings, and heaved it into the lire-pit, while other men raked orange-hot charcoal over it until it was buried. The bellows sighed, provoking the fire into a wild outburst of flame. Five men were dragging up the massive square iron swage block. A wide groove, like a gutter but shallower, was cut into the upper face. Daurenja nodded to two of the men, and they each took a sledgehammer from the table. Daurenja himself lifted the top swage, a half-round bar on a long handle; it must have weighed forty pounds, but he moved it easily. He rested it in the groove on the top of the block, and peered into the fire as the third and fourth bellows started to blow, stirring up six-foot plumes of flame.

"Keep the charcoal coming," Daurenja yelled. "Got to keep the heat even." Sweat was pouring out of his face, as though he was melting or leaking. "Right, that'll do, get it out."

The iron plate rose out of the fire-pit like the sun rising, a blazing yellow shape that defeated the eye as it swooped down on top of the groove in the block. Daurenja set the curved face of the top swage down lengthways, exactly in the middle, and nodded to the hammermen, who started striking the swage's flat back, squeezing the hot, soft plate down into the groove, as the men with the tongs drew it down the block, an inch between the fall of each hammer blow. By the time they were halfway down, the bright yellow had faded to orange; Daurenja lifted the top swage clear, and the plate went back into the fire to heat up again. Men came forward to scrub clinker out of the groove with wire brushes.

"You could have done this bit earlier," Ziani said. "You don't need me here for this."

Daurenja swung round and looked at him as though he didn't recognise who was talking to him. "I'm sorry," he said, "but I wanted to keep the heat in the fire. Once this lot cools down…"

It was a fair point, but Ziani made no sign of acknowledging it. "How many staves?" he asked.

"Eight," Daurenja replied.

"Fine. I might go outside for some air."

But he stayed, as they swaged down all eight staves, quenched them, cleaned up and squared off the edges and laid them one at a time on the mandrel to make sure they fitted snugly on the curved face. He wasn't sure why; it was painfully noisy and unbearably hot, and there was nothing for him to do except stand still and quiet and admire the frightening intensity of Daurenja's concentration. For once, he felt no desire whatever to take part, not even to set a square or a pair of callipers on the quenched, fettled staves to test them for straightness or uniformity of thickness. He found his own reluctance disturbing, but couldn't decide why.

"As near as makes no odds," Daurenja panted in his ear; which was his way of saying that the staves fitted together perfectly around the mandrel, their long edges lying so tight that the blade of a rule wouldn't slip in between them. Ziani nodded grudgingly (was it simple jealousy, he wondered; because this was the greatest, most ambitious piece of work he'd ever seen, and all he could do was watch? A part of it, yes, but only a small one), as Daurenja ordered the staves laid flat on the ground, dropped to his knees and began smothering the edges with flux. He worked quickly but with extraordinary care, verging on tenderness, like a mother feeding her baby some pulped-up mess with her fingers. Behind him, everybody was moving; carrying water, shovelling charcoal, damping down the mandrel, the tongs, the air-pipes, brushing off and sweeping up scale, grinding flux, laying out tools in order for the next stage, while Daurenja knelt beside the components of his dream like a man at prayer. Ziani glanced at him as he looked up, and saw that he was wide-eyed and pale with fear.

He's vulnerable now, Ziani thought, for the first time ever. I could get to him now and hurt him. He thought about that, as unconsciously he counted the slow, even gasps of the bellows. A few sharp, insidious words to wreck his confidence, get him worrying; pretend to find fault or foresee a problem. He was so tense that the slightest thing would break him, like a single drop of water on the red-hot air-pipes. It was like watching a lover waiting for an answer (yes or no, like the gauges; either everything fits together or it doesn't), one man kneeling still and quiet while everything behind him was fire and movement. Two possibilities. A genuine choice.

He tried to think straight. If Daurenja failed, what would he do? It was impossible to say. Valens would want to know, would want an informed and reasoned opinion, whether it'd be worth letting him try again, or whether the project was impractical, a waste of precious time and resources. But it wasn't about rational decisions; it was whether to kill the monster now, while he was weak, his guard down, stripped of his impenetrable armour by love and desire. It's the only thing he wants, Ziani thought, so is it better to stop him having it, or let him win his beloved and hope he'll be satisfied and go away?

"Right," he heard him say, in a voice as hard and brittle as glass. "We've only got one chance. If anything goes wrong, we're screwed." He wasn't talking to anybody; he mouthed the words like the responses in a religious service, a prayer, a general confession.

Two of the staves were in the fire, buried under a glazed roof of glowing charcoal. Ziani forced himself to clear his mind. When the staves were white hot, at the precise moment when the surface but not the core of the iron was just starting to melt, they'd be hauled out of the fire and held on the mandrel side by side. In the two seconds during which the surfaces were still molten, they could be joined by firm but gentle hammering, little more than a brisk smack; and that was what Daurenja didn't know how to do.

Success or failure; yes or no.

Rather than choose, Ziani watched the fire, looking for the stray white sparks drifting lazily upwards out of the charcoal oven that would tell him the iron was approaching welding heat. Apart from the snoring of the bellows there was dead silence. They'd put the lamps out, so he could judge precisely the colour of the glowing iron. As he waited, he could feel the tension in his mind, yes or no, the gauge set on the work, and he desperately wished he knew the grounds on which he was supposed to decide.

The sound of welding-hot iron is unmistakable; almost a crackle, almost a smacking of lips, against a background of hissing. Ziani took the rake from someone's hand and gently opened a window in the roof of shining coals. Almost immediately a spark shot up, bright as a star, burst and went out. He could hear the hiss but not the crackle. The problem was the thickness of the staves. Welding thin pieces was easy enough, so long as you didn't let them get too hot and burn; but thick pieces like these had to be welding-hot all the way through, or else the seam would be weak and false. The biggest risk lay in waiting too long once the sparks began to fly, burning the outside while waiting for the inside to run. Then there was dirt, rust or scale in the seam, which would stop the edges merging into one piece-the flux was meant to guard against that, but if you waited too long the flux would burn away, scale would start to form. Pull the staves out too soon, before the melt started, and you could hammer as hard as you liked and nothing would happen. He felt the skin on his forehead burn, and his eyes were bleached from staring into the painful brightness of the fire, but he found he couldn't move away, not until the moment came…

(It was yes, then. He took it calmly, with resignation, putting the implications away at the back of his mind for later.)

Seven plump white sparks soared up out of the fire, and the crackle was like snapping twigs. "Now," he heard himself yell. He felt a hammer-shaft in the palm of his hand-someone must've put it there-as the two staves rose up from the glowing heap, white as the moon. As they moved through the air towards the mandrel, he noted dispassionately the slimy, wet look of the surfaces where the iron was softening into liquid. Everything was perfect as the staves slid gently on to the mandrel and the edges to be welded nudged together and touched, needing only his gentle strokes, his caress, to join them inseparably for ever.

I know how to do this, he thought as he lifted the hammer; not a prayer or an exhortation, a simple fact. He struck, and a shower of burning white stars, droplets of molten iron, shot up in front of his eyes like a fountain. He felt some of them on his cheeks, his wrists, the backs of his hands, melting his skin as he struck again, patting and squidging the wet staves together like a potter moulding clay. There were good smiths, excellent smiths, who never managed to learn the knack of the forge-weld, lacking the touch, the passion, the love. One blow slightly too hard would spring the joint before it had a chance to form; slightly too soft and the skin on the wet surfaces wouldn't burst and open up to each other. The sparks scattered and buzzed round him like furious bees, sweat flowed down his forehead and the bridge of his nose-one drop on the seam could ruin it, but he didn't dare wipe his face or move his head at all-while his arm rose and fell, his wrist delivering the delicate pecks, like kisses. People who believed in gods reckoned that a creator made the world. For a short while Ziani was prepared to believe in something like that; a god who gripped the Earth in mighty tongs, lifted it white hot out of the sun and joined its seams with careful, passionate taps, filling the night sky with sparks, somehow made sense; and whether he made it as a paradise for the righteous or a trap or a weapon had no bearing on the holiness of the moment when the edges fused into a seam, and the mountains sank hissing into the sea.

"Well?" Daurenja's chin was on his shoulder. "Has it taken?"

He didn't know; unbelievably, he wasn't even looking. "Too late now if it hasn't," he shouted back. "You'd better look for yourself, I can hardly see."

Which was true enough. He closed his eyes, but the all-consuming white glare was still there. "It looks fine," Daurenja yelled in his ear. "It's taken, we're all right."

Ziani opened his eyes, but he couldn't see anything. "Good," he said. "Now for the tricky bit. Get the mandrel in the fire, quick, before it takes cold."

The tricky bit; because to weld on the remaining five staves and close up the final seam, they had to keep the piece he'd just welded at or just under welding heat for the rest of the procedure; and that, as far as Ziani knew, was impossible. Someone was pouring water over his head and shoulders; someone else was binding strips of soaking wet cloth round his forearms. They'd lifted the two staves he'd already joined off the mandrel and nestled them back into the fire, a little further out towards the edge, while the next stave was buried deep in the heart of the coals, close to the mouths of the four air-tubes. His forehead was already dry again. Someone took the hammer from his hand and quenched it in the water-filled trench. It hissed, and a round ball of steam drifted upwards.

As he listened for the iron, he allowed his mind to wander. He tried to picture the City-the factory, his home, the Guild school, the house where he'd been born-but the light was too bright. So he searched in it for the faces of his wife and daughter, and found he couldn't quite form their shapes. They were two white pools, two pieces at welding heat, but however hard he tried (though the edges were clean as arrow blades and he was using blood as a flux), nothing he could do was quite enough to form a seam. Right at the heart of the fire was a cold spot. No matter how forcefully the bellows blew (they were piling on the charcoal, they were throwing on cartloads of sawn timber, wrecked wagons, smashed arrows, dead horses, dead men, whole cities, and each breath of the bellows bathed the fuel in white light and burned it away), still the cold spot was there, in his house, in her eyes, the night they came to search for the illegal mechanical doll. He could see it clearly now that the light had bleached his mind. He could see the door opening, the faces of strangers, a cold draught blowing into the warm house, lamplight on a halberd blade. I don't understand, she says; Ziani, what are they talking about, I don't understand. He understands, of course; he's guilty, he shares a truth with the strangers but not with his wife. He looks at her, sees fear and confusion and a refusal to believe, but something else as well, a cold spot. But it's a totally new procedure, an innovation, an abomination, and so he has no frame of reference, not until now, when he sees the same flaw in the white iron, and the two moments touch and weld…

He was hammering. The sparks lashed his face like rain, and he couldn't tell for certain whether the salt he could taste as he licked his lips was sweat or tears or just the last of the salt bacon. But somehow the cold spot had collapsed; he pecked at the growing seam and watched the shadow inside the translucent iron wince, as liquid metal flowed from one piece into another. "It's taken," Daurenja howled, and quietly, in the back of his mind, Ziani agreed. Not a thunderbolt or a sudden stab of understanding; it was more that, when he probed the thought, like a man with toothache feeling with his tongue, he knew that he could no longer believe in what he used to believe. The cold spot was still there, as thought cooled and it became too late to make it good.

It was her, the cold spot said. She told…

The hissing again, like the voices of other people who knew something he didn't. Sparks; he could smell his own hair burning. "Now," he called out without even needing to look; and they dragged out the two pieces; seven eighths of a cylinder, and the missing eighth stave. There were a dozen men straining on the tongs now, staggering under the weight of the blurred white shape as they slid it over the mandrel like a sleeve and Daurenja laid the eighth stave gently on top. Two seams to make in one heat, there wouldn't be time. He worked them alternately, hardly thinking about what he was doing, going by the feel of the soft iron under the hammer, since he could no longer see. His face was raw from the heat, even the hammer's wooden handle was too hot to grip. His throat and lungs were burning, he was drowning in heat and light, but all he could think about was the cold spot, the flaw in everything. It was her, she told them; in which case…

Suppose (in his mind, by contrast, it was bitter cold) he was Duke Valens. Suppose he found out that Ziani Vaatzes opened the gates of Civitas Eremiae. Just suppose. Needless to say, it would change everything. It was a cold spot in the war, a flaw in everything. But the war must be fought to the end, and without Ziani Vaatzes it couldn't be won, and so the cold spot had to be overlooked, the seam had to be closed up around it, he had to forget about it or pretend he didn't know it was there. Now (let's suppose) he's Ziani Vaatzes, staring at the cold spot in the heart of the white glow, knowing that everything he's done is unsound, so brittle that one tap in the right place will shatter it. If the cold spot had been in the first seam, or the second, the third, the fourth, fifth, sixth or seventh; but the eighth seam, as they shovel the last city on to the fire and lean on the bellows handles, with Daurenja standing over him twitching and whimpering with lust… The eighth and last seam, closing up the tube.

"That's it." Daurenja's voice, raw as though the lining of his throat had been scraped with glass. "That's it, leave it, you've done it."

"It's no good." Daurenja was trying to pull him away, take the hammer out of his hand. He struggled, put his hand on Daurenja's face and shoved him. "There's a cold spot. There's a fucking cold spot in the last seam."

Daurenja shouldered past him, thrust his face, his bright eyes and his stupid little button nose, so close to the yellow iron that his eyelashes shrivelled. "Where?" he yelled. "Where is it? I can't see anything."

Funny joke. Ziani could barely see at all, only round the edges of the terrible white hole. He wondered how he could possibly explain. "It's there," he said. "I felt it."

Daurenja was huddled over the glowing tube like a mother over a cradle. He was bathed in the steam from his drenched clothes, the wet sheepskin he'd draped round his head and shoulders. The light from the bright iron shone in the cloud. "There's nothing there," he said. "It's all right, you're imagining it. It worked, you did it. I knew you could do it. It worked."

Two men were trying to pull him away now, before he scorched his face and ruined his eyes, but his skin hadn't burnt and he wasn't even blinking. Only a hero or a monster could get that close to yellow iron and not burn. (Wasn't that what the savages believed, that you could try a man with hot iron? If he burned, it meant he was guilty, or was it the other way round?) "You bloody genius, Ziani," he was yelling, his voice high and shrill, "I knew you'd be able to do it, I knew all along, right from the first time I saw you, and I was right, wasn't I? I knew there had to be a reason, I knew it was the right thing to do." They were trying to make him move, hauling at his shoulders and arms, but they couldn't shift him, and as the iron gradually cooled, he seemed to grow even stronger, as if the heat was leaving the tube and draining away into him (but he didn't burn, only sweated).

"Right." Ziani heard his own voice, barely recognised it. "Get the hoops in the fire, I want this job finished. Wait till the tube's gone dull red and then quench it; oil, not water. I need to sit down for a bit and close my eyes."

"Yes, of course." Daurenja was still staring into the light, cooling it with his eyes. "Get the first hoop up to white, and for crying out loud keep them in order." At last he turned his head away, looking at Ziani. "There wasn't a cold spot, was there? I looked, but I couldn't see anything."

"I don't know," Ziani replied. "I could've been wrong. I thought I saw it, but…"

"There wasn't one," Daurenja said. "You imagined it. Hardly surprising, staring into the weld all that time, it's enough to screw up anybody. Look, we can finish now, shrinking the hoops on is no big deal. Why don't you go and lie down or something? You must be wrecked."

"I'll just go outside for a while," Ziani replied. "It's a bit too warm in here."

The night was dark and cold, and the stars were just sparks from the weld, he knew that now, just as the moon was hot iron and the clouds were steam. He stared into the darkness until the white rip began to heal, gradually shrinking until all that was left of it was a scar, a blemish, like a fault in a seam. It was still there when he closed his eyes. It was her, then. She told them.

Well, then. The City would still have to fall, he couldn't prevent that; no choice now. He'd condemned it to death a long time ago, in the bright white light of his lamp, when he changed the specification. By the illuminating glow of the cold spot-how much would he be able to see before its light faded?-he saw her standing in the doorway of his workshop, a silhouette with the firelight behind her, her head a little on one side as she watched him.

"What are you doing?" she said.

"Just drawing."

She came a step closer. "Work?"

"No. Actually, it's for Moritsa. Something I'm thinking of making for her."

A step closer still, and her body was between him and the yellow glow, so that he could only just see the paper in front of him on the table. "That's nice. What is it?"

Carefully he put the pen back in the ink bottle. "You remember when we went to the Guild fair, and they had those dancing mechanical dolls?"

A pause; then, "Oh yes. They were funny. She really liked them."

"I know." He looked for her face, but it was in shadow. "I thought I'd make her one."

"Really? Do you think you could?"

The surprise in her voice delighted him. He'd always known she admired him, was proud of having such a clever husband. It'd be a present for them both, in a way. "I don't see why not," he said. "Basically it's just clockwork, with some cams and levers. I got the specification from the library this afternoon, I was just drawing it out. Here, take a look if you like. Don't suppose it'll mean much to you, though."

He felt her hair on his shoulder as she leaned over him. "It's all just lines and squiggles," she said. He laughed. "Will it dance like the ones at the fair?"

"Well, no. They were Type Sevens, this is a Type Four. Type Seven is a restricted pattern."

"Oh." It wasn't much. A little inflection, probably not even intended. A cold spot. "Well, never mind. Will it be able to turn its head and move its arms?"

"Of course. Here, look, this is the linkage mechanism. This arm here bears on this cam, which raises this pawl here…"

She giggled. "If you say so," she said. "But it looks really difficult and fiddly, all those bits and pieces. It'll be a lot of work, won't it?"

"I'll just do a bit at a time, when I've got a spare moment. I'll enjoy it. It's been ages since I did any small work."

"I know she'd really like it," she said. "But you work so hard as it is, at the factory. You'll wear yourself out, you will."

He smiled. "You know me," he said. "I hate just sitting still. Anyway, I like making things. That's why I became an engineer, right?"

He wasn't looking at her face, but he could feel the warmth of her smile, like the heat of a fire making his cheek glow. "It'd mean a lot to her," she said. "Specially if you made it for her. She's very proud of her clever daddy."

"Well, then."

She neither moved nor spoke, but she didn't need to. The moment's hesitation, a cold spot, said it for her: it's a shame it won't dance, though, like the ones at the fair. And at that moment (the white rip was fading from his vision, he could barely see) it occurred to him that it would be better if it could dance, even though it was a Type Four. Why couldn't a Type Four dance? Well, because it wasn't a Type Seven. Sevens dance, Fours turn their heads and move their arms, that's why we have types. Dumb question. You might as well ask why the sun doesn't shine at night.

She left him, and when she'd gone the light came in through the doorway and he could see the machine again, lines on paper. Why couldn't a Type Four dance? But it could, if you duplicated the pivot-and-socket assembly, driving it off the main spindle with an auxiliary train…

He froze in his seat, suddenly cold all over. Just thinking about it was enough to make him shudder. Type Four was the kind that didn't dance; for dancing, there was the Type Seven, and that pattern was restricted. It wasn't hard to understand, for crying out loud. He could almost feel pain from the guilty thought, lodged in his head like an arrowhead in a wound; as if they could cut the top off his skull and find it there in his brain. He screwed his eyes tight shut, as if concentrating could crush the malignant thought like gallstones.

But it could be done. Worse than that; if it was done, the result would be better, an improvement, just like the modifications to scorpion mechanisms he'd submitted to the governors of the ordnance factory. Yes, he told himself, but that's permitted, one specific exception to the otherwise inviolable rule.

It would mean so much to her. He thought about that. To deviate from Specification was forbidden; but just because a thing's forbidden doesn't mean it's not possible. Quite the opposite. Murder, for example. Murder was forbidden, but it was possible and it happened. There was no need to prohibit walking in fire or flying through the air. Murder happened all the time. It was possible to do it, and possible to get away with it, provided that nobody ever found out.

"Dinner's ready": her voice from the other room. It would be as bad as murder; worse, in the eyes of the Guild, since it was a crime against the whole Republic rather than just one man. Very well, he thought; I've been tempted, just as I've been tempted to kill people, and of course I've resisted the temptation; because I know right from wrong; because I daren't run the risk of getting caught.

It would mean…

He blinked. The great white glare was closing up, and he couldn't see through it any more. Suddenly he realised it was raining. His hair was dripping wet, and water was running in streams down his forehead into his eyes. Only an idiot stands out in the rain when he doesn't have to. He opened the door, and heard the dull, heavy sound of hammers on hot metal.

They were shrinking on the strengthening bands. He watched as someone lifted a white-hot hoop out of the fire, carried it gripped in tongs to the mandrel and slid it tentatively on to the tube. Someone else teased it quickly down the tube with a length of brass rod, until it rested up against the previous band; straight away, someone else stepped forward and poured water on to it from a brass jug, quenching it so that it shrank, gripping the tube so hard it could only be removed by cutting. It would be a long job, since every inch of the tube had to be reinforced, but it was straightforward enough, just a slight variant on the technique used for fitting an iron tyre to a wheel. Another hoop went in the fire; further back, two men were welding hoops over the horns of the anvil, scattering white sparks as they patted the glowing iron. But he didn't want to watch. Simple welds, they didn't need him for that. He yawned.

Someone walked past him, stopped. "Are you all right?" He thought about that and realised that no, he wasn't. Every square inch of his exposed skin was scorched, and the muscles and tendons of his arms were aching horribly. He looked down at the palm of his right hand, then at his forearm, where the welding sparks had pitched and raised fat white blisters. "No," he said.

"You want to get those burns seen to," whoever it was said. He sounded concerned, which was strange. "And then you want to get some rest. You've earned it."

He recognised the voice. It was Daurenja. "You look terrible," he said.

Daurenja laughed. "Quite likely," he said. "But who give a damn? It worked, that's all that matters. You did it."

Ziani shook his head. "There's a cold spot," he said.

The words melted against Daurenja's smile like drops of water falling on the hot iron. "No there isn't," he said. "And if there is, it'll be all right, the bands'll hold it. Tube and bands together, that's three inches of forged wrought iron. Nothing on earth's going to get through that."

"Maybe not," Ziani replied. "But there's a cold spot."

Daurenja turned away and walked past him without another word. That pleased him, and he thought about something Duke Valens had tried to teach him, about the way to a man's heart. Through the eye, into the brain, deep into the mind until you reached the place where the staves didn't join and the seam was weak. Valens hadn't seen fit to mention that the entry channel of the wound closed up once the sword was pulled out, like an underground shaft caving in, leaving the damage buried deep inside, stoppered like a bottle with a scar until something, a bright light perhaps, opened it up again, and for a moment or so you could look into the wounded man's eye and see the damage looking back at you from the mirror.