The second day at the bellows began two hours before dawn. Just then, the dark rock walls of the workshop were still cold to the touch.
Old Monster Gui sat upon his three-legged stool beside the draft pit. An iron poker was resting across his knees. He had laid out four distinct types of coal on a split-pine plank. Porous pine charcoal, dense black-oak hard coal, rotten-egg bog coke, and rare iron-core charcoal dredged from underground stone veins.
“In the grand sect refining halls,” Gui said, his voice raspy as dry river pebbles, “they use Earth-Fire veins tapped with jade water gate-gates. The potion-maker turns a silver wheel, and the fire rises or falls by half an inch. Here, you have only hardwood, dry sheepskin, and coal. If you can’t read the fire by its eye, you’re blind.”
Gui pointed the iron poker at the hearth grate.
“Tell me what you see when coal burns.”
Pei Jing stood in the draft pit, his hands resting lightly on the oak lever. “Burning is the rapid rusting of carbon and volatile organic compounds. As the reaction accelerates, the radiant energy emitted shifts along a fixed magnetic spectrum.”
Gui blinked, his yellowed eyes narrowing. “Speak human words, clerk. What are the colors?”
