The brick maintenance flue descending from the River Lantern’s cellar vault to the subterranean Re-Claim Chamber had been laid five centuries ago by masons who worked in dressed granite and Roman cement, building a four-foot-wide vaulted passage on a thirty-degree slope deep into the belly of the Old Hill. In earlier cycles, when Jon Hale and Alden Bram had crept down these forty stone steps with a hooded lantern to inspect the bronze viewing plate, the tunnel walls had been weeping cold marsh groundwater that smelled of iron rust and wet fern.
Tonight the bricks were dry and radiating a fierce, baking heat that made the leather of Jon’s boots curl at the welts.
Running parallel to the left-hand wall at shoulder height, the twelve-inch cast-iron pipe of the municipal cold-water brake shuddered on its forged iron wall-brackets. Inside that iron skin, the river water diverted through the twenty connected cellars of Low Sike and South Lane was fighting a losing war against the thermal output of the three-ringed Crown Furnace below. Every three seconds, a violent hydraulic hammer—the sound of steam pockets collapsing and re-forming against cast iron—went boom-clank down the length of the pipe, shaking flakes of ancient lime-scale onto Jon’s shoulders as he descended step by step with the stone bowl cradled in his left arm.
