In the vaulted distillation chamber of Entry hall 642, three levels below the Central Hearth, the great potion-made retort had been brought to working heat.
The retort was an extraordinary relic of First Dynasty building. A massive ball-shaped kettle four paces in width, cast from dense glowing-bronze that had aged to a lustrous, dark green rust patina. Suspended above a deep earth-heat fissure that blasted high-pressure fiery steam through fluted dark rock vents, the kettle hummed with an unbroken, low-hum deep ring that shook through the floorboards at eighty-two hertz.
Around the outer edge of the retort stood four cooling coils fashioned from spiraled tubes of pure copper, sunk in troughs of cold stone spring-water that ran through from the upper drain tubes. At the discharge end of each copper coil hung a series of teardrop-shaped flasks blown from clear underground quartz crystal, designed to collect the distilled fractions.
The vault itself was carved from dense chlorite flaky rock, its dark green walls glistening with condensed herbal oils. The floor had been paved with square blocks of stone-hard hardwood, providing a dry, secure footing for the healers as they stoked the steam gates and monitored the condensing tubes.
Clan-Mother Zhen presided over the fire platform, her nettle-silk robes tied back with woven hemp cords. Her eyeless face was calm, bathed in the amber glow of the steam vents, her webbed hands moving over the bronze stopcocks and pressure relief valves with intuitive, masterful certainty.
