"First, raw iron is forged into thin sheets, called 'pot iron.' These are arranged in a vitriol tank in overla…
"First, raw iron is forged into thin sheets, called 'pot iron.' These are arranged in a vitriol tank in overlapping rows like fish scales and left to soak for several days. The iron sheets are gradually eaten away by the solution and covered with a reddish deposit. This deposit is scraped off, washed, and placed in a furnace for smelting and refining. After three courses of smelting, the copper is complete. Any iron that has not yet dissolved is replaced with fresh sheets and returned to the tank."