The air in Entry hall 412 was rapidly becoming unbreathable.
From the cut fuel lines of the downed clockwork hound in the last hall, a thick, greasy yellow vapor was drifting northward along the ceiling vaults. It was the packed exhaust of an artificial spirit-fire. Distilled burning acid, rendered pig fat, and volatile sulfur-oil processed under high pressure by the alchemists of the Azure Firmament Sect.
Where the vapor brushed against the damp limestone stone wall-brackets, the stone hissed, shedding a thin skin of white, bubbling froth as the acid ate into the ancient white lime-chalk.
Qiao Ming walked briskly through the center of the gallery, his face covered by a square of coarse linen soaked in clean well-water and dusted with powdered wet lime plaster. The lime stopped the acid in the air. That let him draw shallow, steady breaths without burning his windpipe.
Behind him, Yan Zhiqiu wore a matching damp mask, her dark eyes watering slightly from the chemical fumes that slipped around the margins of the cloth. She carried her unstrung bow in its oiled case, keeping the precious horn stave away from the acid-burning mist.
“The outside sects poison everything they touch,” she said, her muffled voice thick with disgust. “Even their machines don’t burn clean oil. They burn skin-burning acid to wring every ounce of speed from their brass gears, heedless of the destruction it leaves in the air.”
