The descent into the clockwork vaults beneath Sluice Nine was like climbing down into the hollow ribs of an iron giant beast.
Following Qiao Ming down a spiral stairs cut directly into the living solid mountain stone, Yan Zhiqiu felt the air turn freezing, damp, and overwhelmingly heavy with the stone scent of wet iron and stone-hard cedar. Sixty arm-lengths beneath the floor of the writing hall, the spiral stairs opened into a cavernous vaulted gallery two hundred paces long. There were no decorative friezes here, no carved star-patterns, no calm marble statues.
This was the engine room of the tides.
Massive gears of cast sea-bronze, eight paces in width, were mounted on axles of hammered star-fallen iron thicker than a ship’s mainmast. Their teeth, each the size of an anvil, were coated with thick, dark animal fat that smelled of mutton fat and pine-rosin. Huge chains of hand-forged bronze links—each link as heavy as an ox—dangled from overhead pulleys into upright stone shafts that vanished into the lightless underground deep pit below.
At the far end of the gallery rose the Great Leaf of Sluice Nine. A huge massive stone slab of black dark rock, forty arm-lengths wide and thirty arm-lengths high, sliding in upright bronze-faced guide channels anchored six deep-water lengths into the bedrock.
