Entry hall 225 was the westernmost castle wall of the Drowned Siphons—the great end-post gatehouse of Sluice-Gate Seven.
Here, the stonework of the Second Epoch met the raw, crushing violence of the outer cosmic ocean. The chamber was a huge upright shaft, seventy arm-lengths square and ninety arm-lengths high, quarried directly from the densest black dark rock bedrock. Suspended in massive, oil-greased granite guide-rails that spanned the entire height of the shaft hung Sluice-Gate Seven. A massive stone drop-gate of green-veined dark rock and naval bronze, sixteen arm-lengths wide, twelve arm-lengths high, and five arm-lengths thick, weighing twelve hundred tons.
Suspended above it were twin tube-shaped balance weights of solid lead, each thirty feet long, tethered by four-inch cables of woven glowing-bronze wire that ran over huge six-spoke pulley wheels cast during the First Dynasty.
Outside the green dark rock gate, the outer deep pit was waking.
Through the thick stone inner walls, Qiao Ming could feel the deep, rhythmic shudder of the moon-tide line-up tide. Twice every lunar cycle, the posture of the drowned moons exerted a huge gravity pull upon the cosmic deeps, forcing trillions of tons of deep-sea water against the outer hull of the Ark. The outside pressure was mounting steadily toward two point four tons of pressure—enough force to crush an iron void-ship into a crumpled ball of foil.
