Entry hall 214 was a sound engine forged during the height of the First Architectural Dynasty.
The hall was ninety paces long and forty arm-lengths high, shaped like the inside of an inverted ship’s hull. Unlike the stone chambers of the upper cloisters, the walls here were sheathed in linked plates of cold cast bronze, five inches thick, pinned to the dark rock bedrock with massive copper rivets. Thirty-six hollow fluted pillars rose from the floor to meet the ribbed ceiling, each pillar punched holes in with curved sound-chimney pipes tuned to specific shaking frequencies.
To the ignorant eye, it looked like a grand ritual hall of bronze kings. To a water mapper who understood sound mechanics, it was a massive sound amplifier designed to fade moving blast waves through sonic standing waves.
Qiao Ming stood on the high gallery beside the northern water-hammer gearwork, forty arm-lengths above the floor. His bare calloused feet rested upon the cold bronze plates, feeling the faint, unending hum of the metal.
The metal was ice-cold to the touch, coated with a thin film of green rust that gave off the sharp, metal scent of rusted copper. In his left hand, he held his ash stave. In his right, he held a heavy copper-headed pin used to release the high-pressure trip-lever.
