Air pressure was an unpaid laborer with an inexhaustible work ethic.
At the lip of the flooded Lower Karst Basin, five thousand feet below the surface, Giles Croft adjusted the brass fine-scale measuring tongs on his liquid silver empty pocket gauge.
The dark waters of the underground lake stretched into the vast, echoing cave like a sheet of black glass, rippling gently against half-sunk limestone arches.
Beside Giles stood Aldous Swift-Current, the colony’s chief high-pressure engineer.
Aldous held a flanged wrench, his oilskin coat dripping with water drops from the high cave vault.
Behind them, Master Borin Bronze-Lung’s dwarven mechanics were tightening the final bolts on a thirty-six-inch ductile cast-iron channel pipe.
The heavy pipe snaked up over a natural limestone saddle thirty feet above the water level before plunging down into a deep upright sinkhole shaft leading to the mountain’s lower drainage deep pit.
“The air empty pocket pump has evacuated thirty inches of liquid silver from the channel apex,” Aldous reported. He tapped the glass dial with his fingernail. “The entire two-thousand-foot line is sealed tight.
