The Intercepting Flint

Could eight hundred pounds of leaded flint glass cross two hundred paces of greasy cobbles before the midday bell tolled the death of three fishermen? Kiri'ata did not wait to debate the odds. She drove an iron crowbar under the timber skid supporting the Great North Beacon condenser, levering the oak frame until dry wood groaned against the stone floor of her western quay workshop.

"Take the trailing balk," she told Paora. "When I lift, kick the first tallow roller under the bevel."

Paora spat into the sawdust, planted his wide shoulders against the cradle, and hauled back on the hemp tackle. His broad face turned the color of boiled beetroot. "This cart was greased with stolen pig fat," he wheezed. "Cheap rendering, full of rancid bladder and gutter trimmings. A decent cooper uses mutton suet. My nostrils are peeling."

"Push, Paora," she said.

The heavy disk shifted. Eight hundred pounds of cast glass, four feet across and ground to an exact double-convex curve, slid forward on its oak cradle. Teuira caught the side stays with calloused hands, checking the iron strapping around the rim. Her navy coat was already gray with lime dust from the threshold.

"The marine patrol on the jetty changed guard ten minutes ago," Teuira said, nodding toward the half-open doors. Beyond the lintel, the gray basin of Ha'amene lay shrouded in lifting vapor. "Twelve men with bayonets, but their backs face the roadstead. Governor Tautoru ordered them to watch the civilian net-sheds for pitch pots. They will not look at an empty lighter if we keep low."

"We take the flat-bottomed timber lighter moored at the oil slip," Kiri'ata said, kicking the second roller into place and throwing her weight on the bar. "A skiff rolls too easily. A single wake would tilt our optical axis four degrees, and four degrees at four hundred paces throws the focal point thirty yards off the mark."

The three of them drove the skid through the double doors. Cold salt air struck them immediately, thin and wet, carrying the raw bite of the bay. Across the water, Barge Nine sat dead in the roadstead, its black oak hull chained to granite mooring buoys. Down in the forward hold, Marama and his two crewmen were held under marine guard beneath locked iron gratings, while ten casks of wet blasting powder lay secured in the aft magazine.

Kiri'ata wiped sweat from her brow with her sleeve, leaving a streak of grey emery across her cheek. The cloud deck above the high cliffs was tearing apart. Broad patches of pale winter blue opened over the bay.

"Forty minutes," Teuira said, checking the iron pocket chronometer pinned inside her tunic. "Eleven and forty. At twelve and twenty, the sun clears the parapet."

"Then move," Kiri'ata said.

They ran the heavy lens down the ramp of the oil slip. At the water's edge lay the timber lighter, a broad platform used for hauling coping stones. Paora jumped down onto the wet deck, his boots gripping the slimy fir planks. He caught the guide ropes and hauled the skid aboard until the craft settled with a sullen wallow.

Kiri'ata knelt upon the wet deck. She pulled a brass plummet and a length of waxed linen line from her leather apron, dropping the lead weight against the central thwart. She took out a stick of chalk.

"We do not anchor," she said, her voice clipped. "Anchors drag when the tide turns. Paora, take the aft sweep. Teuira, take the bow oar. We bring the lighter into the lane sixty yards northeast of Barge Nine. If we align directly in the vector from Tower Seven, the lens sits between the shooter and the powder."

"You want to catch an incendiary beam on four inches of bare glass?" Paora grunted, heaving on the stern sweep until the craft swung away from the jetty. "If that light can rip an oak timber in half, it will crack this beacon disk into sand."

"It will crack," Kiri'ata agreed, sighting along the timber cradle toward the high bulk of Tower Seven. The fortress tower rose two hundred feet above the harbor mouth, its slit embrasures dark and narrow. "Flint glass has high lead content. It absorbs heat four times faster than crown glass. But before it cracks, its curvature alters the angle of refraction. The sniper is projecting a convergent beam through a concave mirror. His light meets at a single killing point. Our lens is double-convex. When his beam enters our front surface, the leaded glass will bend the rays outward, making them divergent."

She drew a chalk line across the deck, marking the angle of declination.

"He wants a point of fire," she said. "We give him a scattered fan."

The lighter drifted into the middle channel. The marine guards on the distant jetty remained focused on the shore, their brass helmets gleaming under the pale sky. The water here was deeper, dark and cold, slapping against the blunt bow.

At eleven and fifty, the sun broke through the coastal fog.

The harbor transformed. The gray gloom vanished under a sheet of hard glare. Sunlight struck the green water, turning every ripple into a needle of silver. High above the roadstead, the granite face of Tower Seven began to glow in the midday light. Its southwest embrasure, a narrow gun port sixty paces below the lantern platform, caught the solar arc.

Kiri'ata stood beside the massive lens. With an oily rag, she wiped the tallow coating from the front face. The leaded flint emerged clear and pale green, thick as an ox's flank, reflecting her weathered face and scarred palms.

"Paora, hold the sweep two points to port," she commanded. "The wind is drifting our stern. Teuira, lash the front skid to the iron ring-bolt. It must not tilt when the swell hits."

Teuira worked the wet hemp, throwing two half-hitches over the ring. "Tamatoa is up there. I see the brass mounting bracket in the slit. It is trained on the barge."

Kiri'ata checked the chronometer on Teuira's chest.

Twelve and eighteen.

On the foredeck of Barge Nine, the marine sentry paced beside the locked forward hatch grating, adjusting his bayonet while looking out toward the southern jetty.

Twelve and nineteen.

A strange hush settled over the roadstead. The wind dropped, leaving the harbor basin flat as oil.

Kiri'ata threw her shoulder against the timber cradle, making the final alignment. She looked through the thick lens, keeping her eyes low to avoid the focal axis. Through the leaded crystal, Tower Seven appeared warped, its granite blocks twisted into a distorted curve.

At twelve and twenty, the light struck.

There was no sound, no flash of black powder, no warning smoke.

A circle of white heat, bright as the heart of a forge and barely a foot across, slammed into the front surface of the flint lens.

The air around the lighter hissed instantly. The salt water clinging to the hull turned to vapor with a sharp spit. The smell of scorched timber and hot lead rose in a blinding choke. Inside the glass, deep internal tensions began to sing, a high-pitched ringing vibrating through the deck planks beneath their boots.

"Hold the stay!" Kiri'ata shouted, her knuckles white against the oak lever.

The concentrated beam hit the convex curve. Instead of converging onto the powder casks of Barge Nine, the refracted light bent violently outward. A fan of scattered radiance sprayed across the open water, boiling the brine thirty yards wide of the target in a roaring froth of steam.

On Barge Nine, the marine sentries yelled in terror as the sea beside their hull erupted into boiling spray, completely untouched by fire.

Then came the thermal shock.

The leaded flint could not endure the unequal expansion. With a sharp crack that echoed across the granite roadstead like a cannonade, a web of fractures tore through the four-foot disk.

The jolt threw Kiri'ata back against the deck thwart. Paora lunged, catching her collar before she tumbled into the churning wake.

Above them, the shattered lens did not fall. Held together by its iron rim, the fractured crystal acted as a thousand tiny prisms. A brilliant back-reflection flared along the exact path of the incoming beam.

A needle of refracted light traced the vector across the bay, shooting upward in an unbroken line and striking straight into the southwest gun port of Tower Seven.

High in the dark slit, a figure recoiled from the brass bracket, throwing up an arm as the reflected glare struck him full in the face.

"Tower Seven," Teuira breathed, her voice cutting through the steam. "The southwest slit."

Kiri'ata pushed herself up from the wet deck, her burned fingers gripping the splintered cradle. Across the water, the path of the killer lay drawn in light.