Thirty feet into the gallery, the ancient baked-clay trunk opened into a low, vaulted junction chamber where the stonework was built of squared granite cut stone instead of common river brick. Here, the floor was slick with warm, stone-heavy water drops that dripped from the ceiling arches in steady, rhythmic plinks.
Pella raised her lantern. Bolted directly over a box-shaped breach in Hal Rook’s baked-clay pipe sat a massive, gleaming piece of modern machinery. It was a heavy bronze saddle, four feet long and curved to fit the outside width of the glass-fused trunk. Unlike the rustic iron collars of the old ferry line, this casting was flawless, polished bright and sealed with heavy red lead paste around its outer edge.
Cast into the crown of the bronze saddle was the embossed crest of the College of Summoners. An open eye surrounded by seven streaming water gate gates. Above the crest, an iron running wheel projected vertically toward the low stone ceiling. Its threaded bronze stem was held fast by a heavy locking nut. Droplets of water drops sizzled against the warm casing, giving off a sharp aroma of pipe lime and hot metal.
The metal was so hot that when Pella touched the outer pipe rim with her bare knuckle, she pulled back with a sharp hiss of pain. The heat streaming from the bronze was intense, turning the small granite chamber into a stifling vapor bath. Droplets of water striking the upper casing turned instantly to steam. It filled the chamber with the sharp, healing odor of hot sulfur and pipe lime.
“It’s an academy restrictor,” Pella said. Her voice shook with anger as she inspected the mounting. She knelt carefully on the wet stonework. That kept her wool trousers clear of the scalding puddle beneath the valve. “They didn’t just ignore Hal’s tag. They tapped directly into his relief bypass and clamped a high-pressure throttle onto it.”
Eren crawled into the chamber on his hands and knees. He dragged his heavy toolbox and a lantern behind him. When his eyes adjusted to the warm glow, he let out a low whistle through his teeth. “Look at the mass of that casting. That’s two hundredweight of bell bronze. That wasn’t hauled down through our larder. They must have lowered that from the street under-road drain when they rebuilt the High Sluice bridge three winters ago.”
He reached into his leather bag and pulled out a brass-bound wooden folding rule. He unfolded the segments with crisp clicks. He laid the wood across the pipe rim. “Four-inch throat on a thirty-six-inch baked-clay pipe. That’s like trying to force a draft horse through a dog door. Look at the neck of that valve bonnet. The bronze is cast with reinforcing ribs, but the studs are standard naval bronze.”
“They’re dumping the Crown’s boiling overflow right into Hal’s drainage trunk,” Pella said. She ran her brass measuring tongs over the clamping studs. “The saddle is forcing high-pressure discharge down a pipe designed for gravity flow. Look at the mortar seams on either side of the casting. The river silt is baking dry, and the baked-clay is starting to craze under heat shock.”
Eren set his hand against the granite wall. The entire bedrock block was humming with a dull, sickening ringing hum that set the teeth in his jaw buzzing. “They’ve choked the bypass down to keep the pressure high in the central pipe hub upstream. If this throttle gate is jammed shut, where does the excess water go when the river rises?”
“It goes into the cellars,” Pella answered, her voice cold with certainty. “It backs up through every back kitchen trap, every brewery sump, and every tenement well in Lowbank. They’re using our foundations as an unvented pressure tank so Master Sorell’s fountains can spray fifty feet in the air on the High Terraces.”
She took a piece of chalk and marked the position of the bronze stem on the valve collar. It was screwed down to within three threads of the bottom stop. The valve was almost entirely closed. It allowed only a fraction of the necessary relief volume to pass through.
Eren pulled a scrap of sourdough crust from his apron pocket. That turned it over in his fingers without eating it. “Fourteen years of quiet flooding. Every time an old woman on Fish Street complained about water in her coal bin, the ward court guard told her it was high tide. It wasn’t the tide. It was this damned bronze saddle choking the life out of the river.”
Pella reached out and examined the four heavy bronze studs securing the saddle. They were crusted with turquoise copper green rust, but the threads were undamaged. “The hardware is sound, but the internal gate is frozen under backing-up pressure. We need a tone check before anyone touches that wheel. If we force it, the bronze gate will crack, and forty pounds of steam will blow right into our faces.”
She took her dark oak-ink bottle and a small wooden ruler from her pocket. She drew a line across the pipe rim seam to serve as a witness mark, then recorded the bolt spacing on her tally slate. Beside the bronze collar, the dark silt stench of the lower sump wafted up from an open check hole, thick with rotting weed and sulfur.
“Look at the packing gland on the spindle,” Eren pointed out, shining his lantern directly into the bonnet recess. “They used lead-impregnated flax packing. But the high-pressure steam has cooked the animal fat out of the fibers. It’s as hard as horn. If we try to turn that iron handwheel without loosening the gland nuts, the spindle will seize on the threads.”
“We don’t touch the wheel today,” Pella decided, her voice steadying. “Not until Ada has sounded the gate. She has an ear for seated bronze. She can tell from a hammer tap whether a valve is frozen on its guides or just bound by scale.”
“And if it’s frozen?” Eren asked, wiping the red lead smudge from his thumb onto his leather apron.
“Then we rig a bypass around the saddle before we touch a wrench,” she said. “We don’t gamble with eighty pounds of steam in a stone vault that has no back door.”
They spent twenty minutes checking the four granite stone wall-brackets supporting the vault ceiling. The stonework was stable. But the mortar between the granite blocks had turned powdery from nonstop heat cycling. Pella took her measuring tongs and measured the gap between the bronze pipe rim and the baked-clay pipe bell: exactly three-sixteenths of an inch. The saddle had settled half an inch into the clay.
“It’s crushing the pipe,” Eren muttered. “The weight of that casting is resting directly on Hal’s baked-clay wall. We need to brace this vault with ash timbers before Ada steps foot inside, or one good hammer tap will send two hundred pounds of bronze straight through the floor.”
Pella picked up a handful of loose river sand from the floor. That let the fine gray grains slip through her fingers. “Hal always said that bronze was a liar. It looks clean and expensive on the outside. But when you put thirty years of river silt against it, it seizes up tighter than church doors on tax day. We need Ada’s wrench, and we need her patience.”
Eren took his scraper and carefully chipped away a hardened lump of pipe lime that had formed over the lower bonnet seam. Beneath the white crust, the original green paint of the College Water Power was still visible. It was stamped with an inventory number: S-414. ‘They cataloged it,’ he said, his voice flat with disgust. ‘It’s on their books as a seasonal pressure control valve. They knew exactly how much water they were choking off from the lower district.’
Pella picked up her grease pencil and wrote the inventory number directly onto her check slate, underlining it twice with black dark oak-ink. ‘When the town court guard asks why the cellars on Fish Street are floating, we won’t show him a horoscope. We’ll show him S-414, bolted to a thirty-six-inch baked-clay main with four bronze studs and twenty pounds of lead paste. Let Master Sorell explain why his seasonal control valve has been screwed shut for three winters.’
Beside them, the boiling puddle on the granite flags hissed softly as a drop of cold water drops fell from the roof arch. everyone could feel the smell of wet stonework and old iron. But the measurements were taken. Every stud, every thread, and every hairline fracture was recorded on the slate. They had the physical truth of the channel locked in numbers, ready for the plumber’s eye.
They crawled back toward the air-flow chute, dragging their tools behind them in the narrow bore. The cool surface draft was a welcome relief against their burning faces. It carried away the stinging stench of heated sulfur. ‘Hal always said that an honest measurement never apologized to a town elder,’ Pella murmured as she reached the mouth of the larder. ‘We’ve got the numbers now. Let’s see what Harrowby makes of them.’