The aqueduct was an open trench of black snake-like stone, four arm-lengths wide and two arm-lengths deep, cut into the center of the hall floor. In the ancient days of the First Epoch, it had carried fresh meltwater from the high alpine reservoirs down into the cooling drain pits of the central writing hall, preserving the humidity needed to keep delicate silk rolls and thick parchment leaves from turning brittle in the dry mountain air. Now, it was choked with a solid plug of hardened silt that had hardened into white stone over ten thousand years of flooding.
Qiao Ming knelt beside the stone channel, his bare knees resting upon the wet pale limestone flags. He laid his horn lantern on the stonework coping and drew his green rust bone-awl from his leather cross-belt. With a practiced, rhythmic flick of his wrist, he drove the sharp three-sided tip of the awl into the upper crust of the deposit.
The stone layer cracked with a dry, glassy snap, parting to reveal the internal stratigraphy of the silt-bed. He brought the lantern close, leaning down until his weathered face was inches from the fracture, his nostrils flaring as he tested the scent of the exposed settled mud.
