The Dragon in the Vessel (Aurora Consurgens)

A medieval-style illumination depicting an alchemical operation set against a dark green ground. On the left, a figure wears a pink tunic and green-and-white mi-parti hose, leaning over a wooden apparatus to press a white substance. To the right, a large, translucent, bell-shaped vessel sits amidst stylized orange flames. Inside or encircling the base of the vessel is a blue dragon with spotted flanks, its tail curving upward. A small black bird, often representing the nigredo or putrefaction stage of alchemy, stands atop the dragon's back. The scene is framed by a simple border.

This image is a quintessential illustration from the 'Aurora Consurgens', a 15th-century alchemical treatise attributed to Thomas Aquinas. It visualizes the chemical transmutation processes of the Great Work, specifically the stages of dissolution and heating within the athanor.