The shift from the sunlit round hall into the South Aqueduct was a descent into an unbroken mountain night.
The roar of the open tiered arena, where sixteen hundred voices had shouted their farewell from the upper galleries, died behind the four-hundred-foot stern of the Brass Sovereign. In its place rose the deep, enclosed hollow thunder of sixty thousand cubic arm-lengths of high-pressure salt water racing through a seamless tube of native granite.
The aqueduct was a building monument of the First Dynasty. Carved thirty arm-lengths wide and twenty-four arm-lengths high through the roots of the Southern Shelf, its walls bore the rhythmic, slanted tooth-marks of bronze chisels swung eight hundred years ago. There were no pillars, no timber braces, and no mortar seams. The entire water chute was a single negative sculpture carved out of the mountain’s living skeleton.
The high-pressure shape of the channel had been calculated to prevent standing blast waves. The cross-section was neither box-shaped nor circular, but an inverted curved catenary that kept a uniform flow speed across the entire wetted outer edge. As eighty thousand tons of water rushed down the granite raceway, the boundary friction against the stone generated a paper-thin sheath of tiny air-bubbles. A natural lubrication film that allowed the vessel to glide with near-zero drag.
