At eight o’clock in the evening on the twenty-first day, Senior Inspector Korr Var led the check party through the heavy bronze back gate into the central upkeep ring of the Sluice Crown. The door was four inches of solid bell-metal, sealed with three lead-lined rubber rings. He swung shut behind them with a muffled, tomb-like thud that cut off the sound of the rain.
The inside of the vault was a huge underground cave hollowed out of the living limestone of the High Tor, two hundred feet beneath the Senate House. It was fifty yards across, lit only by the eerie, sickly green soft glow streaming from hundreds of glass holding tubes mounted along the circular gallery walls. The heat hit them like an open fire door. Forty-four degrees of damp, choking steam that coated their wool clothes in oily water drops within thirty seconds.
At the center of the cave, suspended forty feet above a boiling pool of river water, hung the central rig. A huge, tube-shaped cage of interlaced cast-bronze bars, forty feet in width and sixty feet high. Inside that cage, churning with terrifying violence, was the elemental spirit Senn. A vast, branching current of glowing river water that thrashed against the bronze bars like a harpooned giant beast. It sent showers of scalding white spray cascading into the deep pit below.
