Crawling through forty feet of three-foot baked-clay channel was second nature to Ada Morland. In thirty years of commercial upkeep in Harrowby, she had squeezed through Victorian brick sewers beneath the textile mills, squirmed through hospital pipe chases packed with asbestos lagging. Then she slid on her belly through flooded crawlspaces beneath town swimming baths.
“Good canvas, this,” Ada’s voice echoed back to Pella as they neared the junction. Her headlamp beam danced across the inside seams. “Dima’s done a proper double-stitch on the lap. Air’s coming through sweet enough. A bit of soot and cedar dust from your yard, but nothing that’ll choke a set of lungs.”
Pella crawled directly behind her, holding the spare lantern and the wooden tool roll. The air in the gallery grew noticeably hotter as they passed the thirty-foot mark. The smell of pipe lime was intense. It mixed with the heavy sulfur steam that puffed intermittently from the fractured baked-clay crown ahead.
Every six feet, Ada paused to tap the baked-clay wall with her gloved knuckles. ‘Hear that?’ she called over her shoulder. ‘The clay sounds dead on the bottom side where the silt sits, but up on top it’s ringing like fine bone china. That means the pipe is under tension. The pressure inside is trying to turn an oval bore into a true circle, and glass-fused clay hates being stretched. It has great crushing strength, but zero pulling yield. You put fifteen pounds of internal high-pressure stretch on clay. It shatters like a dropped teapot.’
Pella observed the craftsmanship of the channel as they advanced. The terracotta segments had been fitted with spigot-and-socket bells. It was sealed with beaten oakum rope and a thick fillet of high-pressure lime mortar. Where the steam had leaked, the lime had softened into a wet paste that smeared like gray curd under their knees.
When Ada reached the low granite junction vault, she didn’t rush toward the bronze saddle. She sat back on her haunches on the damp flat stone slabs. Her eyes swept the room in a careful, skilled circle. Her white headlamp lit up the vaulted ceiling, the wet stonework walls. The heavy ash timber balks Eren had wedged under the stone arches.
“Eren know what he’s doing with an adze?” Ada asked, reaching out to tap one of the upright timber props with the knuckle of her glove.
“His family built the ferry slips for three ages,” Pella answered. She crouched beside her in the narrow stone space. “He framed the whole lower wharf.”
“Thought so,” Ada murmured, nodding in test. “Good timbering. Ash holds its grain under damp squeezing better than pine. He’s cross-braced the header into the granite stone wall-brackets with proper oak wedges. If that roof decides to settle another half inch, the wood’ll groan and give us three minutes of warning before the stone drops. That’s honest carpentry.”
She swung her headlamp downward. She pointed the sharp beam directly at the massive bronze saddle clamped over Hal Rook’s baked-clay main. The brass eye of the College of Summoners gleamed through the water drops. It was surrounded by weeping crusts of chalky copper green rust and scorched red lead paste.
“Good timbering. Bad plumbing,” Ada said flatly, her voice dropping into the no-nonsense register she used when inspecting an apprentice’s botched radiator installation. “Look at that clamping arrangement. Four six-inch bronze studs driven through mild iron saddle straps, seated right on glass-fused clay without a single rubber or fiber seal ring to take the differential spreading. What did they think was going to happen when the pipe took eighty-degree water?”
“They didn’t think about heat,” Pella said. She wiped a runnel of sweat from her cheek with her apron bib. “They thought about static pressure. They needed to force the water through the Crown’s turbines. They used Hal’s line as a blind plug.”
“Idiots,” Ada pronounced with cold and exact finality. “Look at the electric-shock rusting between the bronze studs and those mild iron straps. The iron is flaking away in sheets like puff pastry. The moment those straps rust through, the clamping force transfers directly to the baked-clay bell. That’s why your cracks are running lengthwise instead of circumferential.”
Ada pulled a pocket heat gauge from her vest, touching the copper probe to the baked-clay surface four inches from the bronze pipe rim. The digital needle climbed rapidly, settling at sixty-two degrees.
“Sixty-two on the clay,” Ada noted. She took a stick of grease pencil from her pocket and writing the number directly on the granite cut stone behind her shoulder. “And the water inside must be running near boiling under that head. The clay is expanding at one rate, the bronze saddle is expanding at twice that rate. The granite vault is cold as river ice. The materials are fighting each other for room to breathe, Pella. That’s why your baked-clay is crazing.”
She leaned closer to the three hairline fractures Pella had marked earlier. The cracks were leaking tiny. It spat jets of scalding salt water that hissed against the stone floor. It filled the vault with a hot, saline fog that smelled of ancient silt stench and heated sulfur.
“The cracks haven’t opened to an eighth of an inch yet,” Ada observed. She ran the tip of her brass feeler gauge along the narrowest fracture. “They’re still hairline. That means the glass-fused core is holding its hoop tension, but only just. If someone drops a water gate upstream and sends a blast wave down this bore, the whole section will unzip like a cheap paper bag.”
She reached into her cantilever box. Then she pulled out a sixteen-ounce brass ball-peen hammer and an eight-inch six-sided brass drift punch. The metal of the tools gleamed clean and bright in the headlamp beam, fully free of the mystical engravings and rune tracks that academy summoners insisted on carving into their instruments.
Ada laid down a thick rubber kneeling mat over the sharp rubble, protecting her knees from the wet flat stone slabs. ‘A dry knee makes for a calm hand,’ she told Pella. ‘If you’re squirming because cold water is soaking through your trousers, you rush the job. And rushing a seized valve is how you break the spindle.’
She looked up at the ceiling stone wall-brackets where water from the street above dripped in steady, cold drops. ‘We’re thirty feet below stone floor level. If this vault floods, we’ve got ninety seconds before that crawlway fills to the crown. That’s why you never enter a dead-end chamber without an approved exit protocol. Your Courtesy Bridge isn’t magic, Pella. It’s an emergency fire door with a sound alarm.’
Ada inspected the four foundation bolts holding the saddle straps to the granite footing. She took a wire brush from her pocket, scouring away the green rust until the bolt threads were exposed. ‘Ten threads per inch, standard Whitworth form,’ she noted, taking out her thread pitch gauge. ‘Your local guild smiths didn’t invent this thread. They bought these studs from foreign ironmongers in the upper port. The nuts are six-sided, but they’re cast soft. If we put a heavy socket on them, the corners will round off like butter.’
Pella knelt beside her, recording the bolt measurements on her tally slate with black dark oak-ink. The air in the chamber had cooled slightly with the nonstop canvas draft. But the stone beneath their knees still shook with the deep, sickening pulse of the trapped river. ‘Hal left three spare collars in the old ferry warehouse,’ Pella said. ‘Forged iron with lead rubber rings. If this saddle ever cracks, we could replace it with a bolted sleeve.’
Ada nodded, adjusting the headlamp strap. ‘A bolted sleeve with a full-face rubber seal ring is ten times safer than this rigid casting. A rigid saddle on a flexible clay pipe is an invitation to disaster. The moment the ground settles, the bronze acts like an anvil and breaks the pipe’s back. But first, we need to know what’s happening inside that gate.’
She checked her watch again. Nineteen minutes and forty-five seconds leftover. The clock was ticking, but her pulse was steady as an iron piston. She took a deep breath of the canvas-fed air, set her drift punch against the bronze casting. Then she leaned in close.
“Right,” Ada said, settling her weight squarely over the tool. “Let’s see if this gate is seated or stuck. Keep your fingers clear of that pipe rim, love. When bronze talks, you want to be listening, not bleeding.”
Pella held the second lantern high against the arched roof. She watched the older woman’s square dark shape against the sweating granite. She pulled a piece of grease pencil from her pocket, noting the time and the forty-two pound heat estimate on the margin of her slate. The canvas chute continued to hiss beside them, delivering its rhythmic cargo of fresh autumn air and the distant, reassuring clatter of Lowbank’s carts.
Down here in the dark, thirty feet below the bells of St. Jude’s, the city’s grand summonses were stripped of their incense, their gold foil, and their high holy Latin. All that remained was six inches of cast bronze, four seized iron studs, and the cold, unbending pressure of three thousand tons of river water waiting to find a crack in the mortar.