Two lamp-wax storm lanterns hung from the blackened oak ceiling beams of the vaulted cellar beneath the Fish Street Cooperage. He cast warm yellow light across stacks of iron-hooped ale casks and an exposed six-inch lead drainage main running along the river wall. The cellar smelled of sour hops, wet oak staves, animal fat pipe-joint compound, and the faint, warm stone breath of the river bed outside. Pella Rook stood beside a pine backboard clamped to the stonework pier. There, a three-foot U-shaped glass tube half-filled with red-dyed water was coupled to a brass test cock on the drain line.
Her voice was unrushed and clear against the low thrum of the stone wall, her fingers stained faint carmine from mixing cochineal dye into the pressure gauge water an hour earlier. Standing before the pine board were Garr and Tomas, two barrel-chested brewery draymen in leather aprons whose hands were calloused thick as horsehide from rolling five-hundred-pound hogsheads up cellar skids. But who leaned toward the fragile glass tube with hushed, squinting concentration.
With the tip of her wooden ruler, Pella pointed to the two levels of red liquid inside the upright glass legs. Because the right leg was open to the cellar air. Meanwhile, the left leg took the static head of the town drain pipe through a brass needle snubber, the fourteen-inch upright difference between the two red meniscuses reported exactly half a pound of backing-up pressure per inch. While the tiny, rhythmic tiny bounce at the top…
