Chapter 18: The Wings of the Mountain

To the military theorists of the early nineteenth century, the defense of a
mountainous territory required the dispersal of troops. A commander had to place
garrisons at every pass, build fortresses at every crossroads, and keep
thousands of men sitting in cold stone outposts, waiting for an enemy who might
never come.

But to Amine, this was a mathematical error. Dispersal was weakness. An army
that was everywhere was strong nowhere.

"If we place fifty men at every pass in the Djurdjura, Yusuf," Amine said,
standing on the high northern parapet of the fort, his telescope focused on the
distant, white-capped peak of Lalla Khedidja, "we will have no army left to
fight. The French or the Janissaries will attack a single pass with five
thousand men, crush our sixty defenders, and march into our valley before the
next outpost even knows they have crossed the border."

Yusuf adjusted his wool cloak against the sharp spring wind. "But Sidi, if we do
not garrison the passes, how will we know they are coming? A scout on a fast
horse still takes three hours to ride from the eastern gate at Tizi N'Ait Aicha
to this fort. By the time he arrives, his horse is dead, his news is old, and
the enemy is already in our olive groves."

"We do not need a horse to carry the news, Yusuf," Amine said. "We will use the
wind."

He turned to his drafting table, which had been set up on the flat stone of the
battlements, held down by heavy brass weights. On the parchment was a drawing of
a tall wooden mast, ten meters high, carrying three movable wooden arms at the
top.

"This is an optical telegraph," Amine said, his pencil tracing the mechanical
joints. "The French call it the Chappe Semaphore. It was the secret of
Napoleon's speed. With this machine, we can send a message across forty miles
of mountains in less than five minutes."

"With wood and rope?" Yusuf asked, squinting at the drawing.

"With wood, iron wire, and brass gears," Amine corrected him. "At the top of the
mast is a long, central horizontal beam—the regulator. At each end of the
regulator is a smaller, independent arm—the indicator. Inside the stone tower
below, the operator turns three brass dials connected to the arms by
high-tensile iron wires and copper pulleys. By manipulating the dials, the
operator can place the arms into one hundred and ninety-six distinct positions."

He picked up a small, leather-bound booklet from the table. Its pages were
filled with columns of neat, hand-written numbers and words in both Tamazight
and Arabic.

"This is the codebook," Amine said. "Each position of the semaphore arms
corresponds to a number. The first signal will indicate the page in this book;
the second signal will indicate the line. A two-number code can convey nearly
four thousand distinct words and phrases—'cavalry approaching,' 'infantry in the
pass,' 'send forty Zouaoua,' or 'the road is clear.'"

He looked at Lounes, who was assembling the brass dial mechanism on the bench.

"We will build three towers, Lounes. The first will be at the eastern pass of
Tizi N'Ait Aicha. The second will be on the high peak of Lalla Khedidja—the
highest point of the range, looking down upon the entire valley. The third will
be here, on the gatehouse of the fort."

"And how will the men at the second tower see the first?" Lounes asked. "It is
fifteen miles of mountain air between them."

"They will use the brass glass," Amine said.

He picked up a long, leather-wrapped telescope. It was different from the crude
spyglasses sold by the Algiers merchants. Amine had used the Algiers
glass-workers to grind a pair of custom doublet lenses—one of dense flint glass,
the other of light crown glass—cemented together with Canada balsam. It was an
achromatic lens, eliminating the blurry, rainbow-colored halos that plagued
cheap optics, providing a razor-sharp, magnified image even in the hazy air of a
summer noon.

"With these glasses," Amine said, "the operator at Lalla Khedidja will be able
to read the arms of the eastern tower as clearly as if they were ten paces away.
They will replicate the signal within thirty seconds, and we will read it here
at the fort a minute later."

The construction of the mountain towers was a feat of grueling, physical
heroism.

For two weeks, teams of twenty Zouaoua hauled heavy oak timbers, coils of iron
wire, stone blocks, and the delicate brass gear assemblies up the steep, rocky
slopes of Lalla Khedidja. The peak was over two thousand meters above the sea, a
windswept wilderness of gray limestone and ice where the clouds often sat on the
rocks like wet wool.

But the men worked with a quiet, fierce discipline, their movements regulated by
the shifts of the clepsydra and the promise of pure silver. They built the
towers of thick, dry-stone masonry, designed to withstand the violent winter
gales of the high range, with a small living quarters at the base for the three
operators.

By the first week of May 1828, the three towers were complete.

The white wooden arms of the semaphore on Lalla Khedidja rose against the blue
sky like the wings of a great bird, silent, watchful, and commanding.

"Let us test the reach," Amine said, standing in the gatehouse of the fort, his
achromatic telescope mounted on a heavy brass tripod.

Yusuf stood beside him, a wooden slate in his hand, while Meziane was stationed
at the dials of the fort's own semaphore mast on the roof.

Ten miles away, on the high peak of Lalla Khedidja, the tiny white arms of the
second tower were visible through the glass. They sat in a horizontal line—the
position of rest.

Suddenly, the arms moved.

The central regulator tilted forty-five degrees to the left; the right indicator
swung downward; the left indicator pointed straight up.

"First signal," Amine said, his eye fixed on the lens. "Page forty-two."

Meziane instantly turned his dials, the iron wires clattering through the copper
pulleys as the fort's own mast replicated the position.

On Lalla Khedidja, the arms shifted again, swinging into a new, complex
geometry.

"Second signal," Amine said. "Line eighteen."

Yusuf's finger ran down the columns of the codebook. His face, usually tanned
and dark from the sun, went suddenly pale as he read the translation.

"Sidi..." Yusuf whispered, looking up from the book. "The message is from the
eastern pass. It says: 'Cavalry approaching from the east. Eighty horsemen.
Moving at a trot.'"

Amine did not hesitate. "It is the mock alarm I ordered Yusuf. The scouts at the
pass have simulated an invasion. Let us see how fast our Riders can fly."

He turned to the courtyard below, where the fifty Khayala were stationed, their
horses saddled, their Sabaa rifles resting in their leather scabbards.

"Mount!" Yusuf's voice roared, his saber flashing in the sun.

The fifty riders swung into their saddles, their movements coordinated and
rapid. They did not carry heavy baggage or tents. Each man carried only his
rifle, his cartridge box containing fifty rounds of glazed powder, and his Zouad
wooden box containing four glass jars of preserved mutton and beans.

"The road is clear," Amine said, looking through the telescope as the Lalla
Khedidja tower signaled the final "go" code.

The gates of the fort swung open.

With a thunderous, rhythmic roar of hooves on the compacted stone, the fifty
Khayala broke into a gallop, their gray wool cloaks flying behind them as they
hit the new macadam road.

Because the road was hard and dry, the horses did not slip; they did not sink
into the clay. They moved with a terrifying, continuous speed, the three-team
squads riding in perfect formation.

Amine turned his telescope back to Lalla Khedidja.

Through the glass, he watched the progress of the cavalry. From his high vantage
point, he could see the riders moving along the gray ribbon of the road, five
miles away, their movement so rapid they looked like a shadow sweeping across
the valley floor.

Two miles from the fort, the road entered a deep forest of oak trees.

The Khayala disappeared into the green canopy. A minute later, the tower on
Lalla Khedidja signaled: Riders in the pass. All clear.

"Thirty miles a day," Yusuf said, leaning over the parapet, his eyes bright with
a sudden, overwhelming realization of what they had built. "With this road, and
with these towers, we can defend this entire valley with fifty men. We do not
need to wait for the enemy to find us. We can meet them at the border before
they even know we have left the fort."

"We have conquered distance, Yusuf," Amine said, his voice quiet, his hand
resting on the brass telescope. "An army that has information and speed is an
army that can never be surprised. And an army that cannot be surprised is an
army that cannot be defeated."

He looked toward the north, where the blue peaks of the Atlas met the gray sky.

"The spring is passing. The French ships are mapping the coast. We have our
defense; now, we must begin the final preparation for the siege."