The mounting of Panel Four was the critical clockwork compromise of the entire Quarry installation.
The plate possessed a three-inch hairline fissure running diagonally across its lower left corner. The result of the heat shock suffered during the kerosene explosion in the Salt Works five hours earlier. If that fissure were exposed to the full, high-pressure steam blast inside the main water jacket, the heat cycling would propagate the crack across the entire eight-foot span, shattering the plate and blowing the seal.
Edda had solved the problem not with magic, but with shape.
She had designed an asymmetric mounting frame for the fourth bay. The lead pressure seal ring was set six inches inward from the glass edge, sealing the intact body of the panel firmly against the water jacket. Meanwhile, the cracked three-inch margin protruded into the open air of the drainage gutter.
“Lower it slow,” Edda ordered the chain-hoist crew. “The cracked corner must clear the steel retaining lip by an eighth of an inch. If the glass touches the steel during the drop, the shock will run the crack.”
Varner Crane and Venn held the heavy plate by its padded canvas edges. Their muscles shook as they lowered the two-hundred-pound glass slab into the steel cradle. The cracked corner hung over the wet limestone gutter. It shook slightly in the draft from the air-flow chimney pipes.
