Beyond the general archives of the storehouse lay a specialized hemispherical chamber known as Entry hall 685: The Solar Clock Nook. Here, the heat dropped several degrees, chilled by the massive granite blocks that formed the ceiling dome. In the center of the room stood a huge level sky-high dial, twelve arm-lengths in width, cast from solid star-fallen bronze.
Engraved upon the surface of the bronze dial were nested logarithmic spirals that recorded the precise radiant output of the central sun over a period of four hundred years. Inlaid silver wires traced the declining luminosity curve. He dropped from a broad, radiant arc on the outer edge down into a tiny, shrunken point at the center of the dial.
Qiao Ming approached the dial with bare, silent feet. His calloused soles were cold against the granite paving, but he barely felt the chill. His eyes were fixed on the silver timeline. Beside the dial stood a self-running gnomon. An upright column of dark smoky quartz, six arm-lengths tall, that had once cast a shadow from a beam of sunlight directed down from the surface through a system of high sight relay tubes.
Now, the quartz gnomon was dark, devoid of light. The sight relay tubes eighty leagues above had been crushed by the deluge thousand years ago, choked with deep-sea silt and crushed dark rock. The dial lay in unending underground shadow, lit up only by the amber flicker of their horn lantern.
