II

The *Vent du Sud* hung at two thousand meters, nose into the wind, her envelope taut and her ducted fans turning at idle. She was a Bourbon patrol envelope — old, heavy, hydrogen-filled — but her belly had been cut open and rebuilt. Where the cargo hold used to be, there was now a rectangular bay, three meters long and one meter wide, sealed by two doors that opened outward like the valves of a heart. Inside the bay, mounted on a steel rail, was the launcher: a cradle of riveted iron and brass that held a single strike rocket — two meters of tungsten-tipped steel, its body wrapped in copper wire, its tail fins locked in the folded position, its gyroscope hidden inside the nose cone like a secret inside a fist.

The inventor's name was Farrère. He was thirty-six, thin, nervous, and he had built the gyroscope himself, in a workshop in Toulon, over eighteen months, using brass he could not afford and glass he could not replace. He was not a guild master. He was a navy civilian engineer, which meant he was paid a salary and owned nothing he built. The gyroscope was his. He had told the navy this. The navy had told him that the gyroscope was the navy's. He had stopped arguing because arguing with the navy was like arguing with the weather — it did not change the weather and it made you wet.

Farrère stood in the cabin, bent over the aiming apparatus. The apparatus was simple in concept and impossible in practice: a brass tube, mounted on a swivel, containing a series of lenses — Murano glass, hand-ground, set in brass rings — that projected a magnified image of the ground below onto a frosted glass screen set into the cabin floor. The screen showed the world upside down, because lenses invert, and Farrère had learned to read the world upside down the way a musician learns to read a score — not by translating but by seeing directly. The screen showed the Count's keep: a dark square on a dark hill, lit by the faint glow of lanterns in the courtyard. The keep was small on the screen. The targeting reticle — a brass crosshair etched into the glass — was larger than the keep. This was the problem. The reticle was too coarse. The rocket would hit the hill, or the vineyard, or the chapel, or nothing. It needed to hit the roof.

Farrère switched on the ray light. The ray light was a carbon-arc lamp — a hand-cranked device the size of a shoebox, mounted on a tripod, that produced a thin, blinding beam of white light by passing an electric current between two carbon rods. The current came from a Voltaic pile — a stack of copper and zinc discs in a brine-soaked hemp box — that sat on the cabin floor and smelled of acid and corrosion. The beam passed through the brass tube, through the lenses, and projected a bright dot onto the frosted glass screen. The dot was supposed to align with the reticle. If the dot was inside the crosshair, the aiming lens was aligned with the launcher rail. If the dot was outside the crosshair, the lens and the rail were misaligned, and the rocket would not go where the lens looked.

The dot was outside the crosshair. It was outside by three millimeters — a distance that, at two thousand meters, translated to forty meters of lateral deviation. Forty meters was the difference between the keep's roof and the vineyard.

Farrère adjusted the lens. He turned a brass knurled knob on the swivel mount, one degree, then half a degree. The dot moved. It moved too far. He turned back. The dot moved again. It was closer. It was inside the crosshair, but it was touching the edge, and touching the edge was not enough, because the wind was moving the ship, and the ship's movement moved the lens, and the lens's movement moved the dot, and the dot was dancing on the edge of the crosshair like a moth on a windowsill.

"Open the bay," Farrère said.

The pilot — a guild-licensed man named Vasseur, who had flown patrol envelopes for eleven years and who had never fired a weapon from one — looked at the lord standing beside him. The lord was the Duc de Rohan-Chabot's nephew, a young man named Blanchard, who held no title of his own but who carried his uncle's authority the way a courier carries a letter — visibly, carefully, and without understanding its contents.

Blanchard nodded. "Open the bay."

Vasseur pulled a lever. The bay doors opened. The sound was immediate and enormous — a roar of wind that tore through the cabin like a river through a gorge. Papers flew. Maps flew. The frosted glass screen vibrated so violently that the dot disappeared into a smear of light. The aiming apparatus, which had been steady a moment ago, was now shaking — the brass tube chattering against its mount, the lenses rattling in their rings, the ray light flickering as the carbon rods shifted in the wind.

The launcher, visible through the open bay floor, was trembling. The iron cradle vibrated on its rail. The rocket sat in the cradle, its copper wire catching the carbon-arc light in bright flashes. The trembling was not violent. It was continuous — a high-frequency oscillation, caused by the wind passing over the open bay and creating a vortex inside the cavity. The vortex shook the rail, and the rail shook the cradle, and the cradle shook the rocket, and the rocket's gyroscope — Farrère's gyroscope, his eighteen months of brass and glass — was spinning inside its housing, absorbing the vibration, trying to hold its axis, but Farrère could not know if it was holding, because the gyroscope was inside the rocket and the rocket was hanging in the wind and the wind did not care about tolerances.

"The alignment is lost," Farrère said. "The lens is shaking. I cannot read the screen."

"Can you fire?" Blanchard asked.

"Not without alignment. The rocket will go where the rail points. The rail is pointing at — I do not know. The vineyard. The chapel. Somewhere that is not the roof."

"Can you estimate?"

"I did not build a gyroscope so that I could estimate."

Farrère stood. He pulled a leather harness from a hook on the wall — a webbing of hemp and brass buckles, designed for cargo handling in the bay. He strapped it around his chest and waist. He clipped the harness to a steel cable that ran from the cabin ceiling to a bolt above the bay opening.

"What are you doing?" Blanchard asked.

"The lens must be aligned with the rail. The lens is up here. The rail is down there. I must go down and align the rail to the lens. The lens is stable enough to read. The rail is not. I will adjust the rail by hand, from below, while you hold the lens steady from above."

"You cannot go into the bay. The bay is open. The ground is two thousand meters below."

"The ground is not my concern. The rail is my concern. The rail is one meter below the bay floor. I will hang from the cable. My feet will be on the bay doors. My hands will be on the rail. I will adjust the elevation screw until the rail aligns with the lens. Then I will come back up. Then we will fire."

"The wind —"

"The wind is fourteen kilometers per hour, gusting to twenty. The cable is rated for three hundred kilograms. I weigh seventy. The harness is hemp and brass. It will hold."

"And if it does not?"

"Then you will need a new inventor."

Farrère walked to the bay opening. He looked down. The ground was black. There were no lights below — no villages, no roads, just the dark mass of the Pyrenean foothills and, far below, the faint glow of the Count's keep. The wind roared through the bay, pulling at his shirt, his hair, his harness. The rocket hung in its cradle, trembling, its tungsten tip pointing at nothing.

He stepped into the bay.

The wind hit him like a wall. Not a gust — a wall. A continuous, horizontal force that pressed against his chest and pulled at his legs and tried to peel him off the cable like a label off a bottle. He locked his feet against the inner edge of the bay door — the door was open outward, lying flat against the hull, and its inner edge was a lip of steel three centimeters wide. He stood on the lip. He held the cable with both hands. He leaned forward, into the wind, until his chest was over the rocket.

The launcher was in front of him. The iron cradle. The brass elevation screw. The rail. He could see the vibration — not feel it, see it, the way the rail hummed against its mounting bolts, the way the cradle chattered against the rail. He reached out and pressed his left hand flat against the rail. The vibration traveled up his arm and into his shoulder. He held the rail steady — not still, because no human hand can still a vibrating rail in a twenty-kilometer wind, but steadier. Steadier was enough.

His right hand found the elevation screw. The screw was a brass threaded rod, one centimeter in diameter, that connected the rear of the rail to the mounting bracket. Turning the screw raised or lowered the rear of the rail, changing the launch angle. He turned it. A quarter-turn. The rail tilted. He could not see the lens from here — the lens was in the cabin above him, and the frosted glass screen was beyond his line of sight. He could only align the rail to the lens by feel and by memory.

He had aligned the rail on the ground, in Toulon, in a hangar with no wind. He had marked the elevation screw with a scratch of black paint — a line on the brass that indicated the correct angle for a target at two thousand meters. The scratch was there. He found it with his thumbnail. The scratch was two millimeters to the left of the reference mark. Two millimeters. He turned the screw. The scratch moved. It aligned with the reference mark.

He held it. The wind pulled at him. The cable groaned. His feet ached on the steel lip. His left hand was numb from the rail's vibration. His right hand was clamped on the screw, holding it in place, because the wind was trying to turn the screw for him, and the wind did not know the tolerance.

He needed to tighten the lock nut. The lock nut was a brass hex nut below the elevation screw, designed to clamp the screw in place once the angle was set. He could not tighten it with his right hand — his right hand was holding the screw. He needed both hands.

He let go of the rail.

The wind took him. Not off the cable — the cable held — but sideways, swinging him out over the bay, his feet leaving the lip, his body hanging at an angle over two thousand meters of dark air. The cable swung. The harness dug into his ribs. He grabbed the cable with both hands and pulled himself back. His feet found the lip. He pressed himself against the hull.

He reached for the lock nut. He found it. He tightened it with his fingers — not tight enough, because fingers cannot tighten a brass nut against a vibrating rail in a twenty-kilometer wind, but tighter. He needed a wrench. He did not have a wrench. He had his hands.

He looked up. The bay opening was above him. The cabin light spilled through the opening — a yellow rectangle of warmth and still air. He could see the silhouette of a man leaning over the edge. It was not Blanchard. It was the intendant — Dorléac, who had been standing in the back of the cabin, silent, watching, holding a clipboard, because Dorléac's job was to observe and document, and he documented everything, including the moment when an inventor hung from a cable over an open bay and tried to tighten a brass nut with his fingers.

"Give me the wrench," Farrère shouted. The wind tore the words from his mouth.

"What?" Dorléac shouted.

"The wrench! The brass wrench! In the tool kit on the bulkhead!"

Dorléac disappeared. He returned with the wrench. He held it over the edge. The wind caught it and pulled it sideways. Dorléac gripped it tighter. He leaned further over the edge to reach Farrère's outstretched hand.

The ship lurched. A gust — a real gust, not the steady wind but a sudden, violent shift — hit the envelope from the side. The *Vent du Sud* rolled three degrees to port. The bay tilted. The cable swung. Dorléac, leaning over the edge with the wrench, lost his balance.

His feet slid on the cabin floor. His torso tipped forward. His left hand grabbed the edge of the bay opening — the steel lip, the same lip Farrère was standing on — and his right hand, still holding the wrench, swung out over the void. His clipboard fell. It tumbled, spinning, into the dark.

Farrère saw it happen. He saw the intendant's face — white, wide-eyed, the face of a man who has just discovered that the ground is real. He saw the fingers of Dorléac's left hand sliding on the steel lip. He saw the wrench in Dorléac's right hand, held out over nothing.

Farrère let go of the cable.

He did not think about it. Thinking would have taken too long. He released the cable with his left hand and grabbed Dorléac's wrist — the left wrist, the one attached to the hand that was sliding off the lip. He gripped it. The wrist was thin, thinner than he expected, and the skin was cold, and the bones under the skin were the bones of a man who spent his life at a desk, and the bones were sliding through his fingers because the wind was pulling Dorléac and the harness was pulling Farrère and the two forces were fighting over the same body.

Farrère's right hand found the cable. He pulled. The harness groaned. Dorléac dangled from Farrère's left hand, his feet kicking in the wind, the wrench still clutched in his right hand, his face inches from the rocket's trembling tail fins.

"Hold the wrench," Farrère said. His voice was calm. He did not know why it was calm. It should not have been calm. He was hanging from a cable, holding an intendant over a bay, and the rocket was vibrating against his shoulder. But his voice was calm because his hands were busy, and when his hands were busy, his voice followed.

"I am holding the wrench," Dorléac said. His voice was not calm. His voice was the voice of a man who is being held over two thousand meters of darkness by a thin inventor who weighs less than he does.

"Good. Now give me the wrench."

"You want the wrench? Now?"

"I need the wrench. I need to tighten the lock nut. Let go of the wrench and place it in my palm. Do not drop it."

"If I let go of the wrench —"

"You are holding the wrench. You are not holding me. I am holding you. Let go of the wrench."

Dorléac looked at the wrench. He looked at Farrère. He looked at the dark below. He opened his hand. The wrench did not fall. Farrère's right hand, still gripping the cable, opened slightly — three fingers on the cable, two fingers reaching — and caught the wrench as it dropped. He caught it by the jaw. The handle swung. He shifted it into his palm.

He now had: two fingers on the cable, an intendant hanging from his left hand, and a wrench in his right hand. He needed to tighten a lock nut on an elevation screw that was one meter below him and slightly to the left.

He pulled Dorléac up. Not onto the lip — he did not have the leverage — but high enough that Dorléac's elbow was on the lip and Dorléac could grab the edge with his own hand.

"Hold the edge," Farrère said.

Dorléac grabbed the edge. Farrère released his wrist. He dropped to his knees on the lip — both knees, pressed against the steel, his center of gravity as low as he could make it. He reached down with the wrench. He found the lock nut. He fitted the wrench over the nut. He turned. The nut tightened. He turned again. The nut locked. The elevation screw was fixed. The rail was aligned.

He pulled himself up. He grabbed the cable. He pulled Dorléac up. Dorléac grabbed the cable above him. The two men climbed — Farrère first, then Dorléac — hand over hand, the cable swaying, the wind roaring, the bay below them dark and open and indifferent.

They reached the cabin. Vasseur hauled them over the edge. Farrère lay on the cabin floor, breathing. Dorléac lay beside him, breathing. The wrench was still in Farrère's right hand. He could not open his fingers to release it. His hand had locked around the handle, and the lock was not muscular but neurological — his brain had told his hand to hold, and his hand was still holding, and it would hold until his brain told it to stop, and his brain was busy breathing.

Blanchard stood over them. He looked at the two men on the floor. He looked at the open bay. He looked at the rocket, hanging in its cradle, trembling in the wind.

"Is it aligned?" Blanchard asked.

Farrère opened his fingers. The wrench clattered on the floor. He stood. He walked to the aiming apparatus. He looked at the frosted glass screen. The dot was inside the crosshair. Not on the edge. Inside. Centered. The lock nut was holding. The rail was aligned. The lens and the rail agreed.

"It is aligned," Farrère said.

Blanchard looked at Vasseur. "Fly over the keep," he said. "Level flight. Two thousand meters. When the keep is in the reticle, we fire."

Vasseur brought the ship around. The ducted fans increased their pitch. The *Vent du Sud* moved forward, her nose dipping slightly as the airspeed increased. The wind was from the west. The keep was to the east. Vasseur turned into the wind, then east, leveling the ship at two thousand meters.

Farrère sat at the aiming apparatus. The screen showed the ground moving below — dark fields, dark roads, the faint silver line of the river. The keep appeared at the bottom of the screen, small, square, a faint glow of lanterns in the courtyard.

The ship moved. The keep grew on the screen. Farrère watched the reticle. The keep moved toward it — slowly, then faster, as the ship closed the distance.

"The gyroscope," Blanchard said. "Will it compensate for the ship's movement? The rocket will inherit the ship's forward velocity."

"The gyroscope compensates for deviation from the launch axis," Farrère said. "It does not compensate for the ship's velocity. The rocket will travel forward as well as down. This is why the alignment must account for the ship's speed. The ship is moving at sixty kilometers per hour. The rocket's terminal velocity is four hundred. The forward component is —"

He stopped. He was explaining physics to a lord who did not want physics. The lord wanted the rocket to hit the roof. Farrère wanted the rocket to hit the roof. The physics was the conversation between the wanting and the hitting.

"The gyroscope will hold the rocket on its launch axis," Farrère said. "When the rocket leaves the rail, the gyroscope is spinning. If the wind pushes the rocket left, the gyroscope detects the deviation and adjusts the right fin to correct. If the wind pushes right, it adjusts the left fin. The correction is not perfect. The correction is — I do not know the word. It is what I built. It is what it does. I have tested it seven times on the ground. I have never tested it from an airship."

"Seven times."

"Seven times."

"Successfully?"

"Five times successfully. Twice the gyroscope locked. I do not know why it locked. I believe the lock was caused by vibration in the launch rail. The vibration on this rail is — significant."

"Significant."

"Significant."

Blanchard looked at the screen. The keep was filling the reticle. The lanterns in the courtyard were distinct — individual points of light, not a glow. The roof was visible — a dark square with a lighter patch where the slate had been repaired after a storm.

"Fire," Blanchard said.

Farrère placed his hand on the firing lever. The lever was a simple switch — a brass contact that closed an electric circuit, sending a current from the Voltaic pile to an electric match inside the rocket's motor. The match ignited the solid propellant. The propellant burned for three seconds, accelerating the rocket off the rail. After three seconds, the motor burned out and the rocket coasted, guided by the gyroscope, falling toward the target.

He pulled the lever.

The circuit closed. The match fired. The motor ignited. The sound was a sustained, tearing hiss, like a blowtorch magnified a thousand times, and the rocket moved. It slid forward on the rail, accelerated, cleared the rail, and was gone in half a second. The bay filled with smoke — thick, white, acrid smoke that rolled through the cabin and stung their eyes. The ship lurched — the rocket's departure shifted the ship's center of gravity, and the envelope rose slightly, and Vasseur corrected with the elevator trim.

Farrère ran to the bay. He leaned over the edge. He could not see the rocket. The rocket was below and ahead, falling,its tungsten tip pointing at the ground, its motor burned out, its gyroscope spinning and its fins adjusting when the wind pushed the rocket out of course like it had a mind of his own. He could not see it because it was dark and small and fast and the ground was two thousand meters below.

He ran back to the aiming screen. The screen showed the keep. The keep was still there. The lanterns were still lit. The roof was still intact.

He waited.

The gyroscope was spinning. The fins were adjusting. The rocket was falling. The movement did not care about the reticle or the alignment or the inventor or the intendant or the lord. The movement cared about weight, speed, angle of attack, and the resistance of the air, and these things were happening whether Farrère watched or not, and Farrère watched still trying to figure out the situation he was in.

The keep disappeared.

Not gradually. Not in pieces. The screen went white. A flash — bright, orange, filling the entire frosted glass — and then the screen went dark, because the flash had overloaded the lenses and the frosted glass had absorbed the light and held it for a fraction of a second before releasing it.

Then the screen showed the keep again. But the keep was different. Part of the roof was gone. In its place was a dark circle — a hole — and from the hole, spawning a quarter of the area, a faint orange glow. The lanterns in the courtyard were out. The courtyard was dark.

Dorléac was standing at a second apparatus — a hand-cranked camera, mounted on a tripod, aimed through a port hole in the cabin wall. The camera used a strip of celluloid film, like the ones used to film tournaments and project them at the cinemas. Dorléac was cranking the handle at two turns per second, which produced sixteen frames per second, which was enough to capture the impact and the aftermath in a flickering, unsteady sequence of black-and-white images that would be developed in a darkroom in Marseille and projected before the Bourbon council and said to be proof.

The film showed what the screen showed. The flash. The hole. The glow. The dark courtyard. The smoke — a thin plume, rising from the roof, bending east in the wind.

"Is it done?" Blanchard asked.

Farrère looked at the screen. The glow in the hole was growing. The petrol-stone shell had shattered. The hemp beneath was burning. The fire was spreading. The keep was eating itself from the inside, the way a body eats itself from the heart outward.

"It is done," Farrère said.

He sat on the cabin floor, looked at his hands. His hands were shaking. Not from the cold. Not from the wind. From the knowledge that the gyroscope had worked — that the brass disc he had built in a workshop in Toulon, the disc that had locked twice in seven tests, the disc that he had filed and balanced and re-balanced and prayed over — had spun true for three seconds of flight and had held the rocket on its axis and had delivered two meters of tungsten-tipped steel through the roof of a keep from two thousand meters in the dark.

The rocket fell, and the roof broke, and the keep burned, and the inventor sat on the floor and looked at his hands and his hands were shaking because they had built the thing that did the thing and the thing was done. He didn't know how many died in the explotion, four died and ten were injured of varying severity.

Blanchard ordered Vasseur to return to the neighboring county that served as base. The bay doors closed. The wind stopped. 

The *Vent du Sud* turned west. The keep fell behind them. The fire was a point of light on the dark mass of the hills, growing smaller, then gone.