The dark, pungent liquid bubbling in the distillery retorts behind the blast fire was not alcohol. It was certainly not drinking beer.
It was light peat-tar fire-oil. A volatile, dark amber distillate condensed from the exhaust gases of the peat coking ovens at three hundred degrees.
In the storage yard below the terrace, four massive wooden water tanks banded in heavy wrought-iron hoops held four thousand gallons of the refined hydrocarbon liquor.
The liquid had a specific gravity of zero point eight four—lighter than water, slick as whale oil, and possessing an energy thickness of nearly forty megajoules per gallon.
Giles Croft stood on the timber platform above the central pool. He tested the discharge petcock of a four-inch copper delivery channel.
“The heat energy stored in this pool exceeds one hundred and sixty thousand megajoules,” Giles said. He wiped an oily smear from his wooden ruler. “Equivalent to forty tons of dried black powder, but infinitely more stable in storage.
It needs nonstop oxygen and a pre-heated starting front to sustain burning. It can’t detonate in the tank.”
Mistress Pippa the Fermenter stood beside the copper pipe hub. She held a small glass test retort with long iron tongs.
She touched a glowing charcoal splinter to the neck of the retort.
FWOOSH.
A blinding puff of clear, roaring orange flame leaped three feet into the air, burning with intense, crackling fury that left zero black soot on the glass.
Pippa let out a shrill, delighted cackle, her eyes dancing behind her wire glasses.
“One drop of this wash would roast a bullock whole, Lord Giles,” Pippa crowed. He waved the smoking retort. “It smells like pine pitch, sulfur, and lightning!
When those swamp crawlers wade into the canal, they won’t just drown... They’ll come out crispier than Sunday cracklings!”
“It’s not intended for culinary processing, Pippa,” Giles replied dryly.
“It’s an area-denial heat shield designed to eat the oxygen supply of massed infantry formations and induce rapid heat spallation on hard shell back shells.”
Master Caleb Thorne-Wood and twenty carpenters were working knee-deep in the cold water of the drainage canal below the levee.
They were spiking down one thousand yards of four-inch copper tubing along the concrete centerline of the canal bed. They anchored the pipe with heavy forged iron saddles driven into the floor.
Every three feet along the upper crown of the pipe, small slotted discharge orifices had been punched through the metal, directed upward toward the water surface.
“The pipe stays underwater beneath two feet of canal water,” Caleb called up, checking an anchor strap with his adze.
“If an enemy archer shoots a fire-arrow into the ditch before you’re ready, the water keeps the copper cold. The fuel can’t light inside the pipe!”
“Correct,” Giles said. “The underwater pipe hub remains hydraulically isolated. When the master quick-release gate valve at the pool is opened, water-pressure head forces four thousand gallons of light fire-oil out through the underwater slots.”
Giles gestured toward the straight canal channel stretching between the concrete dykes.
“Because the fire-oil has a specific gravity of point-eight-four, it rises right away through the water column and spreads across the surface in a nonstop, floating four-inch hydrocarbon sheet,” Giles explained.
“It blankets the entire twenty-foot width of the canal for a distance of six hundred yards. One friction igniter dropped into the channel converts the water surface into a nonstop twenty-two-hundred-degree heat incinerator.”
Captain Kenneth Drake walked the canal bank. His pacing rod measured the distance between the water gate and the proposed starting weir.
“A river of fire that flows on top of cold water,” Kenneth murmured, his hand resting on his sword handle knob.
“The Dun-Krag tunnel diggers used pitch cooking pots in the mountain tunnels. But we never had four thousand gallons of boiling grease running in a ditch.”
“Pitch cooking pots are clumsy batch weapons with severe handling risks,” Giles noted. “A nonstop gravity pipeline operates on deep water pressure alone. Zero manpower needed once the valve is tripped.”
To verify that the light fire-oil would form an unbroken surface film without breaking into discrete droplets, Giles conducted a bench test in a copper water chute.
“The spreading multiplier of an immiscible fluid,” Giles explained, adjusting his hair-width, “is determined by the difference between the water’s skin of water and the sum of the water’s skin of the fuel plus the interfacial tension between the two liquids.
Water has a very high water’s skin of seventy-two dynes per half-inch. Because of that, and light peat fire-oil has a water’s skin of only twenty-six dynes, the spreading multiplier is strongly positive. The oil will spontaneously spread into a nonstop razor-thin sheet within seconds.”
Caleb Thorne-Wood scratched his grey temple with a pencil. “So it doesn’t bunch up like animal fat in a cold stew?”
“It flows like water on glass,” Giles said.
“It creates a uniform liquid fuel blanket twenty feet wide across the entire length of the channel. Even against a moderate headwind, surface holding power holds the sheet intact until the starting line is struck.”
Lady Millicent Croft climbed up the access stairs, her tally-book open and her brass nib clicking sharply.
“Four thousand gallons of refined peat fire-oil,” Millicent stated, reviewing the fuel ledgers.
“That represents sixty days of lamp oil and heating spirit for the entire riverport settlement. If you burn that fuel in ten minutes to roast swamp monsters, Giles, the citizens will be eating cold porridge in the dark by midwinter.”
“If we don’t burn that fuel in ten minutes,” Giles replied evenly, “ten thousand hard-shelled hunting beasts will breach the southern dyke, destroy the blast fire, and eat the citizens along with their porridge.
In the hierarchy of town needs, physical survival takes precedence over evening light.”
Millicent paused, tapping her chin with her pencil. “A sound prioritization of heat assets. I have debited the fuel reserves to the emergency civil defense account.”
* * *
By late afternoon, the installation of the copper drain tube channel was complete.
The master control station sat within a heavy concrete pillbox atop Sluice Tower One, directly overlooking the narrowest choke-point of the canal hall.
Inside the pillbox, two heavy brass levers controlled the gravity discharge gates.
Beside the levers rested a row of four magnesium-tipped incendiary darts, connected to tripwire friction strikers mounted upon the canal coping stones.
Giles stood in the watching slit with Toby Karr, inspecting the water flow through the water gate gates.
“Flow speed is steady at four point two feet per second,” Toby reported, reading the floating dial gauge.
“If we open the fuel valve, the fire-oil sheet will cover the entire six-hundred-yard kill-zone in three minutes and twenty seconds.”
“Time your release carefully,” Giles instructed. “If you trip the igniters too early, you waste fuel on empty water tiles.
If you trip them too late, the vanguard monsters will have already scaled the concrete stone retaining walls. The starting must be triggered when the target thickness reaches saturation.”
Before Toby could reply, a desperate commotion broke out along the southern approach path.
Sprinting through the withered reeds, her wild moss-woven cloak shredded by briars, stumbled Yvaine of the Sunken Hollow.
The peat-weaver collapsed onto the crushed dark rock ballast before the pillbox, her earthen mycelium smudge pot rolling across the stones and spewing gray, bitter smoke.
Her hands were covered in black, skin-burning burns, and her face was streaked with mud and blood.
Rook Red-Mane and Kenneth Drake caught her by the arms, lifting her from the sharp stones.
“Yvaine,” Kenneth said urgently. “What happened at the Hollow?”
Yvaine looked up, her dark eyes wild with ancient, ancient dread.
“The deep mire has drowned,” Yvaine gasped, her voice rattling like dried reeds in winter wind. “Hesketh...
He brought sixty offering virgins to the Mother Sump. He split their veins and fed their warm blood into the ancient wallow.”
She turned her shaking hand toward the southern sky, pointing into the heart of the creeping yellow fog.
“She has risen,” Yvaine whispered, tears cutting through the mud on her cheeks. “The Three-Headed Rot-Hydra.
She is sixty arm-lengths from jaw to tail. Her scales are black as midnight, and her three throats cry the acid that dissolves the world.”
Sister Teresa knelt beside Yvaine on the ballast, her emergency medical basket open on the gravel.
With practiced, gentle hands, Teresa washed the black, weeping burns on the peat-weaver’s wrists with a cool solution of harsh cleaning acid and boiled rainwater.
“The venom burns with acid fire,” Teresa murmured, applying a thick healing wrap of powdered zinc oxide and goose grease.
“It bites into the flesh like lye. But the living water tank brings healing to the afflicted. Drink this, daughter.”
She offered Yvaine a horn cup of warm peppermint tea laced with willow-bark extract.
Yvaine drank with trembling gulps, her breath shuddering as the pain began to recede.
“The cultists are marching behind her,” Yvaine whispered, clutching Teresa’s linen sleeve with wild grip. “Hesketh has draped them in dried wolframite armor and black bone plates.
They carry burning brands of sulfur and pitch. They intend to drown the town in black rot before midnight.”
“They will find our town washed clean and our ditches fortified,” Teresa said with cold, calm conviction. “No unclean monster shall cross this threshold while the faithful hold the lances.”
The ground beneath their boots shuddered with a sudden, violent jolt.
Out in the deep marsh, three leagues away, a terrifying sound rose into the gathering twilight.
It wasn’t a beast’s roar.
It was a rhythmic, wet, sloshing surge. The sound of forty tons of draconic flesh dragging through the peat muck, with the wet, clicking scuttle of ten thousand hard-shelled limbs.
The air grew heavy and cold.
A sickly sweet stench of rotting marrow, sulfuric bile, and decomposed swamp gas swept over the levee, so thick that Toby Karr choked and covered his mouth with his sleeve.
Giles Croft reached to his belt, pulling his dark-tinted ironworker’s goggles over his eyes.
He turned toward the control levers, his face as calm and impassive as carved granite.
“Massed bio-threat confirmed,” Giles said, his voice ringing clearly through the pillbox.
Kenneth Drake drew his broadsword, resting the naked blade against the concrete doorstep.
“The men are at the firing steps, my lord,” Kenneth said, his eyes scanning the gathering dark. “The archers have their magnesium arrows nocked. The rail batteries are manned and locked on the firing stakes.”
Giles adjusted his glasses, his hand resting on the polished brass lever of the master drain tube gate.
“Maintain fire discipline,” Giles commanded. “Don’t release the fire-oil until the vanguard enters the concrete throat. We want every gallon of fuel to count. All batteries stand to stations. Prime the fire-oil valves. The raid wave has arrived.”