The Salt-Pan Tidal Scour Gate rose out of the southern salt-marsh like the ruins of a giant stone castle built by an extinct race of giants.
It stood four miles south of Sunken Pilings. There, the broad, flat expanse of the upper tidal flats came together into a narrow stone throat between two natural limestone spurs. Four huge stone support pillars, each sixty feet high and twenty feet thick, built from rust-streaked gray granite blocks fitted without mortar, marched across the three-hundred-foot gap. Between these piers hung three massive bronze-faced water gate gates, each thirty feet wide and twenty feet tall, their lower edges resting upon an underwater doorstep of polished royal dark rock.
Behind the gates, held back by an earthen dike twelve feet high that stretched for three leagues across the salt-pans, lay twenty-two thousand acres of trapped marsh water. The surface of the pool was dark, oily, and still. He reflected the pale morning sky like a huge sheet of black glass. The water level stood ten feet higher than the empty river channel below—a huge, silent buildup of water-pressure potential. It waited behind forty tons of bronze and oak.
Tomas Reed, Nessa Vale, Sile Rook, and Captain Barnaby Miller stood upon the narrow timber narrow high walkway that crowned the central stone pier, fifty feet above the dry channel floor.
The wind up here was fierce and freezing. He smelled of cold mud, marsh gas, and the sharp, ozone tang of approaching weather. Tomas leaned against the iron safety railing. His right hand gripped his walking staff, his left wrist firmly supported by the buckled calfskin brace.
“Look at the balance weight drums,” Nessa said, her voice cutting through the whistling gale. She pointed her brass sighting transit down toward the machinery deck of the central pier.
Mounted upon heavy cast-iron pillow blocks were three huge winding drums of ribbed bronze, four feet in width, geared to massive spoked bull-wheels twelve feet across. Suspended from each drum by links of two-inch forged Swedish iron hung a huge box-shaped ash-wood box, filled with thirty tons of lead pig-iron and river boulders. The balance weights designed to lift the bronze water gates against the water pressure.
Around each winding drum, wrapped five times like an iron serpent, was a logging chain of forged two-inch links.
The chains were secured with three huge padlocks of cast bronze. It was stamped with the crossed-oar crest of the Silt-Road Trade ring. Clamped across each keyhole was a thick disc of stamped lead, hammered cold, bearing Bailiff Taggart’s personal seal.
To ensure the gearwork could never be turned by human hands, three heavy railway wedges of forged steel had been driven into the bronze teeth of the bull-wheels with eighteen-pound sledges, their heads peened over to lock them permanently into the gears.
“They didn’t just lock the gate,” Sile Rook rumbled. He leaned over the narrow high walkway railing. His hooked pruning blade was balanced across his shoulder. “They spiked the gearing. If you put six teams of oxen on that rope winch, the teeth would shear off before the drum turned an inch.”
Tomas ran his fingers along the massive granite blocks of the central pier.
The stone was gray biotite granite, quarried sixty years ago from the deep beds of Mount Sunder forty leagues upstream. Each block was five feet long, three feet high. Then he dressed with fine tooth-chisel margins that had defied two ages of salt spray. The joints between the stones were barely a sixteenth of an inch wide. It was sealed with lead wool driven into the seams with caulking irons. In modern Bellwether, contractors built with cheap river limestone that flaked into chalk after three winters. Here, the empire had built for three hundred years. It poured thousands of tons of dark rock and granite into the marsh to create an unbending monument to public transit.
“Look at the bronze tracks, Nessa,” Tomas said. He pointed to the upright guide slots cut into the pier faces.
The slots were lined with nonstop plates of cast naval bronze, four inches thick, secured to the granite with three-inch bronze spreading bolts. Inside the tracks, the bronze-faced shoes of the thirty-foot water gate gates rested in heavy grease-grooves, designed to allow forty tons of bronze and oak to slide upward without seizing against the stone.
Tomas climbed down the iron rungs set into the granite pier. He stepped onto the machinery deck.
The air here was damp, smelling of old grease, cold stone, and the sour rust of wet iron. He knelt beside the central bull-wheel. He ran his fingers over the peened steel wedge driven between two massive bronze teeth.
“The wedge can be backed out,” Tomas said. He tested the seam with the tip of his cold chisel. “They drove it cold. The bronze teeth yielded slightly, but the casting hasn’t cracked. If we dress the edges with an emery file and drive a hardwood wedge behind the lip, the steel will back out under a hand-sledge.”
Nessa dropped to her knees beside him, her pocket magnifying glass in hand. She inspected the two-inch logging chains that bound the drum.
“Look at the chain links, Tomas,” Nessa noted, tapping the metal with her iron scraper. “This isn’t common bog-iron. This is low-carbon Swedish puddle-iron, forged in the naval yards. It has huge pulling strength, but puddle-iron is stringy. It splits along the melted rock waste stringers if you strike it on the corner with a cold chisel. If we take our twelve-pound sledges and focus every blow on the welded seam of a single link, the joint will shear in eighteen minutes.”
Captain Miller walked to the edge of the machinery deck. He looked up at the huge expanse of water pressing against the upstream face of the gates.
“How much water is sitting behind that timber, Nessa?” Miller asked, his rough voice subdued by the sheer scale of the building.
“Twenty-eight million gallons,” Nessa replied without pause. “Forty-two thousand long tons of liquid head. The water is pressing against the upstream face of these bronze plates with two hundred and eighty pounds of water-pressure force per square foot. That’s why the gates are wedge-shaped: the higher the water rises, the tighter the bronze plates are forced into the granite mortises.”
She pointed to the three-foot upright gap between the lower doorstep and the channel bed below.
“When those three balance weight boxes drop,” Nessa explained, her eyes bright with exact fire, “the gates will rise four feet in six seconds. The forty-two thousand tons of water will plunge into that drop-basin, convert into a thirty-foot wall of moving scouring foam, and rush down the ten miles of raised stone road at thirty-two feet per second. It will hit the silt bar at the Black Shingle like a solid battering ram of water, washing fourteen years of mud straight out into the deep sea trench.”
Tomas stood up. He looked north across the vast expanse of the lower delta. There, the timber towers of Toll-Post One and Toll-Post Two sat upon their earthen mounds.
“Corve knows we have the court injunction,” Tomas said, his voice flat and steady. “He knows Captain Wren’s cutter is at Sunken Pilings. His only play now is to keep this gate shut until the spring rains come and the flood washes away our survey marks.”
“He has forty hired blades stationed at the gatehouse on the south levee,” Sile said. He pointed toward a fortified stone blockhouse half a mile across the dike. “They have three six-pound swivel guns mounted on the low roof wall.”
Captain Miller walked the length of the machinery platform, his sea-boots ringing on the granite flags.
He stopped beside the third winding drum. He peeked down into the dark, churning gap between the pier and the earthen dike. “Thirty-five years ago, Tomas, when I was an apprentice on my father’s barge, I saw this gate open during the great spring thaw. The lock-keeper blew three blasts on an iron horn to clear the channel. When the balance weights dropped, the water didn’t just rush down the chute. It sounded like the roar of a thousand cavalry horses charging across a wooden bridge. In twenty minutes, the entire delta was swept clean of gravel. Every skiff within two miles floated on four deep-water lengths of crystal water.”
Miller touched the cold iron of the trade ring’s padlock, his jaw working bitterly. “And then Holt and Corve put this pig-iron on the drum. They stole the river’s broom, Tomas. They stole the broom and charged us five crowns to walk in the dirt.”
Tomas examined the heavy Swedish iron chain once more through his pocket lens.
The links were three-eighths of an inch thicker than standard anchor chain, their surfaces coated with a black enamel of boiled linseed oil and powdered graphite to resist salt water. He measured the link width with his brass measuring tongs: exactly four inches across the outer bow. It was naval harbor chain, made thirty years ago by the Royal Sea-court for the deep-water booms at Port-Reach.
“A chain like this costs forty silver crowns per fathom, Tomas,” Captain Miller said. He shook his head. “The trade ring didn’t buy this iron out of their pocket. They requisitioned it from the town defense stores during the war scare of Year 030. They used public naval defense iron to lock a public navigation gate.”
“And that makes it a sovereign conversion under Section Three of the Treason Act,” Tomas replied. He closed his measuring tongs. “Every link is an indictment.”
Tomas reached into his courier satchel, pulling out his dark leather ledger. He opened to the new page where the Lower Delta Association charter was inscribed with seventy-four signed names.
“Corve has forty hired men with swivel guns,” Tomas said. “We have eighty wagon drivers with sledges, twenty-eight million gallons of water, and the King’s charter. We start the cut at fourth bell tomorrow morning.”