Chapter 14: The Green and the Gray

The return journey from the Soummam valley was a slow, heavy march against the
rising winter damp. The freight wagons, their oak axles creaking under the
weight of three tons of raw, glittering gray galena and green-veined
chalcopyrite, arrived at Bordj Hamza in the third week of February 1828.

The courtyard of the fort was instantly transformed into a noisy, smoke-filled
metallurgical yard. Amine had no interest in letting the raw ore sit in the
storage sheds; he needed the metals now.

"The lead is simple, Lounes," Amine said, standing by a newly built cupola
furnace near the blast furnace. "Galena is lead sulfide. We roast it first to
burn away the sulfur as gas, turning the gray stones into a red-brown lead
oxide. Then we smelt it in this furnace with charcoal. The carbon in the wood
will strip the oxygen from the lead, and the liquid metal will run out like
water. We can cast it into fifty-pound pigs with no trouble."

"And the copper?" Lounes asked, looking at the piles of green, brassy
chalcopyrite. "My grandfather used to smelt copper in a clay pot, but it was
always full of holes, and it broke when we hammered it."

"Because copper is a stubborn metal," Amine said, his mind projecting the
complex chemical sequence of the Welsh process—the multi-stage smelting method
that had made Swansea the copper capital of the world. "Chalcopyrite is a triple
compound: copper, iron, and sulfur. If you melt it in a simple pot, the iron and
sulfur remain trapped in the copper, making it brittle and useless for drawing
into sheets."

He traced the stages on his stone chalkboard.

"We must smelt it in four distinct fires. First: The Roasting. We burn the
crushed ore on a flat bed of limestone to turn the iron sulfide into iron oxide,
while the copper remains as a sulfide."

"Second: The Matte Smelting," Amine continued. "We melt the roasted ore in our
reverberatory furnace with sand. The silica in the sand will combine with the
iron oxide, forming a liquid slag that floats on top. We drain this slag,
leaving behind 'copper matte'—a dense, dark mixture of copper and sulfur that is
roughly forty percent pure."

"Third: The Blistering," Amine said. "We melt the matte again, but this time we
blow a continuous stream of air over the surface of the liquid metal. The oxygen
from the air reacts with the remaining sulfur, turning it into sulfur dioxide
gas which bubbles out of the liquid. When the bubbling stops, we are left with
'blister copper'—nearly ninety-eight percent pure, but still full of dissolved
oxygen."

"And the fourth fire?" Lounes asked, fascinated by the complexity.

"The Poling," Amine said, his eyes reflecting the yellow light of the forge. "We
melt the blister copper in a deep hearth, covering the surface with charcoal to
exclude the air. Then, we take a green, wet branch of wild oak and thrust it
deep into the liquid metal."

Lounes blinked. "A green branch? Inside the hot metal? It will burn instantly,
Sidi."

"It will burn," Amine agreed. "But as it burns, the moisture and sap in the
green wood will vaporize, releasing a massive cloud of steam, hydrogen, and
carbon monoxide gas. This gas will bubble violently through the molten copper,
stripping the remaining oxygen from the metal. When the copper is pure, it will
turn a beautiful, pale pink color, soft and ductile enough to be hammered or
rolled into sheets as thin as paper. We call this 'tough-pitch' copper."

The poling of the first copper charge was a spectacular, violent event.

Inside the refinery shed, a deep, brick-lined hearth held five hundred pounds of
molten blister copper. The surface of the liquid was covered in a black layer of
crushed oak charcoal, glowing with a dull orange heat.

"Get the pole!" Lounes roared to Meziane and Yusuf.

The two men carried a long, green branch of wild oak, nearly four meters long
and as thick as a man's thigh, which they had cut from the forest that morning.
They positioned the butt of the pole over the hearth.

"Push it down!" Amine ordered.

They thrust the green wood deep into the molten metal.

The effect was instantaneous and terrifying. With a roar like a steam boiler
exploding, the green wood vaporized. A massive geyser of green-white flame and
sparks erupted from the hearth, throwing a blinding, brilliant light up to the
timber roof. The liquid copper bubbled and boiled violently, a thick cloud of
sweet, woody steam filling the room.

Lounes and Yusuf held the pole with all their strength, their faces shielded by
wet wool rags, as the copper violently cleansed itself.

"The color is changing, Sidi!" Lounes shouted over the roar of the bubbling
metal.

Amine peered through his green glass. The dark, bubbling surface of the copper
was turning. The violent boiling was subsiding, replaced by a smooth, oily
ripple. The liquid metal had turned a pale, brilliant pink, glowing with a
clean, incandescent light.

"Pull it out!" Amine called. "It is tough-pitch! Cast it into the sheet molds!"

They withdrew the charred stump of the oak branch, and Lounes tapped the hearth.
The pure, ductile copper ran into flat, shallow iron molds, cooling into flat,
smooth plates of pinkish-gold metal, ten millimeters thick.

The rolling of the copper plates into thin sheets was done on a new machine
Amine had designed and mounted next to the boring engine.

The rolling mill consisted of two massive, highly polished cylinders of hardened
crucible steel, each fifteen centimeters in diameter, mounted one above the
other in a heavy cast-iron frame. The gears that turned the rollers were
connected to the main waterwheel drive, providing an immense, steady torque.

Amine took one of the cast copper plates, which had been annealed—heated to a
dull red and quenched in water to make it soft—and fed it between the rollers.

"Engage the gears, Meziane," Amine said.

The waterwheel caught the load. The wooden gears creaked, and the steel rollers
began to turn with a slow, heavy hum.

The copper plate was drawn between the rollers. With a metallic shhh-clack, it
emerged from the other side, its length doubled, its thickness reduced by half.

They passed the plate through the rollers ten times, adjusting the distance
between the cylinders by a fraction of a millimeter with each pass using a pair
of heavy brass screws at the top of the frame.

By the fifth pass, the copper plate had been transformed into a long, smooth,
glittering ribbon of pink-gold metal, exactly half a millimeter thick—uniform
across its entire width to within a fraction of a hair.

"It is like silk, Sidi," Meziane said, his hand running over the cool, smooth
surface of the copper strip. "It is as flat as the glass of your windows."

"This is the food for our press," Amine said.

The progressive die stamping press was assembled in the center of the workshop.

It was a compact, powerful machine of dark cast-iron, dominated by a massive,
polished flywheel that weighed nearly one hundred kilograms. The crankshaft of
the press was connected to a heavy steel ram that slid up and down between
machined guide-ways.

Amine stood by the machine, his hand on the flywheel.

"The dies are made of our hardest tool steel, Lounes," Amine said. "The
progressive punch has two sections. The first is the blanking punch, which cuts
a circular disk twelve millimeters in diameter from the copper strip. The second
is the drawing punch, which pushes that disk through a polished, tapered die,
drawing the flat copper into a hollow cup with a small, flanged rim."

He fed the end of the rolled copper strip into the guide template of the press.

"Meziane," Amine said. "Turn the wheel."

Meziane seized the handle of the flywheel, spinning it until the heavy iron mass
was turning at fifty revolutions a minute, its weight creating a steady,
rhythmic hum.

Amine engaged the clutch lever.

CLACK-CLACK-CLACK.

The press began its work. With every rotation of the flywheel, the steel ram
descended with a sharp, heavy thud.

As Amine slowly pushed the copper strip through the guide, the machine worked
with a terrifying, efficient speed. The first punch cut the disk; the second
punch drew the cup; and a small, spring-loaded iron finger ejected the finished
cap from the die, dropping it through a copper chute into a wicker basket below.

Clack-clack-clack-clack.

Within one minute, the basket was filled with dozens of perfect, shining copper
percussion caps, every one of them identical in height, diameter, and wall
thickness to within a hundredth of a millimeter.

Lounes knelt by the basket, his large hand reaching inside to pick up a handful
of the caps. He held them up to the light, his eyes wide with a look of
profound, silent astonishment. He had spent his entire life making things one by
one, his eyes and hands negotiating with the metal for every fraction of a
millimeter.

Now, he was looking at a pile of identical objects, born of a machine that did
not tire, did not hesitate, and did not make mistakes.

"This is not blacksmithing, Sidi Amine," the old man whispered, his voice
cracking. "This is... this is a creation. A man cannot count these. They are
like the sands of the sea."

"We do not need to count them, Lounes," Amine said, his voice quiet. "We only
need to fill our cartridge boxes."

The priming of the caps was the final, most delicate stage.

Because dry mercury fulminate was highly sensitive to friction and static
electricity, Amine did not allow his men to handle the powder in its dry state.
Instead, he designed a "wet-priming" process.

The mercury fulminate was mixed with a small amount of gum-water and alcohol
into a wet, creamy paste that was completely safe to handle.

Using a multi-hole brass plate—a template containing one hundred small holes
that aligned perfectly with one hundred copper caps held in a wooden
tray—Meziane used a flat rubber spatula to spread the wet paste across the
plate, filling the holes with an exact, microscopic dose of the explosive.

A second brass plate, containing one hundred small pins, was then pressed down
through the template, pushing the wet paste into the bottom of the copper caps.

The trays of primed caps were then carried to a drying room heated to a steady
twenty-five degrees by a warm-water pipe from the boiler. As the alcohol and
water vaporized, the paste dried into a solid, stable cake of explosive at the
bottom of each cap.

Finally, a single drop of thin shellac varnish was placed over the dried
explosive in each cap to protect it from dampness and prevent the powder from
shaking out during transport.

By the end of February 1828, the drying room held ten wooden trays.

Each tray held one thousand finished, primed, waterproof percussion caps—shining
like gold in the dim light of the drying room.

Ten thousand caps. Enough to fire ten thousand rounds from the Sabaa rifles.

Amine stood in the doorway of the drying room, his hands tucked into his
sleeves, his face reflecting the warm, orange glow of the heating pipe.

"We have the caps, Yusuf," Amine said. "And the first forty Zouaoua are trained.
Now, we must begin the mass production of the barrels."