The fire pit was three feet lower than the workshop floor, dug directly into the fractured black dark rock to tap the natural updraft of the gorge.
At the center sat the brick burning hearth, fed from an underground air under-road drain that ran forty paces beneath the alley to draw fresh air from the outer cliff face. Between the under-road drain and the grate stood the workshop’s lung. A double-acting box bellows built of heavy hardwood planks, clamped with wrought-iron bands, and driven by a four-foot level oak lever.
Old Monster Gui stood before the draft pit at sunrise.
The Three-Legged Mottled Brass Cauldron rested upon its stone base above the hearth, loaded with sixty pounds of crushed river sand and twenty bundles of coarse Earth-Blood Root. It was a low-margin contract batch. Eighty pots of crude blood-clotting salve ordered by the dredger gangs of the lower swamp.
Gui held the iron draft lever in his left hand and a long brass skimming ladle in his right.
“Watch the flame eye,” Gui rasped. He pointed with the ladle toward the mica peephole set into the fire door. “The Earth-Blood Root must boil at the heat where pine pitch softens, but before sulfur catches fire. If you pump too fast, the sap chars against the brass wall. If you pump too slow, the water cools, the medicine curdles. You get forty pounds of grey glue.”
