The Secrets of Alchemy

Detail from Secretioris naturae secretorum scrutinium chymicum, Michael Maier (1687) (CHF Collections/Gregory Tobias)

Detail from Secretioris naturae secretorum scrutinium chymicum, Michael Maier (1687) (CHF Collections/Gregory Tobias)

Zosimos was active around 300 AD. He was born in the Upper Egyptian city of Panopolis, now called Akhmim. Zosimos is thought to have written twenty-eight books about alchemy; alas, most of what he wrote is now lost. We have only scraps: the prologue to a book titled On Apparatus and Furnaces, several chapters from other works, and scattered excerpts. Some of Zosimos’s writings are addressed to Theosebeia, a woman who seems to have been his pupil in alchemical matters, although whether she was a real person or a literary device we will never know for sure. Despite the fragmentary nature of what survives and the difficulty in interpreting it, these writings provide the best window we have onto Greek alchemy. These early texts establish many concepts and styles that would remain fundamental for much of later alchemy.

Zosimos’s orientation toward a central goal (metallic transmutation), his insightful engagement with the practical problems in reaching it, his search for the means of surmounting these problems, and his formulation and application of theoretical principles clearly underscore his writings as something new. Zosimos’s texts witness a coherent program of research that draws on both material and intellectual resources. He describes a wide array of useful apparatus—for distillation, sublimation, filtration, fixation, and so forth—in great detail.

Many of these instruments are adapted from cooking utensils or items used in perfumery or other crafts. Zosimos did not devise all these instruments himself, indicating how developed practical chrysopoeia must already have become by the start of the fourth century AD. The writings of his predecessors form a key resource for him, and he cites them frequently. One of the most prominent authorities is named Maria—sometimes called Maria Judaea or Mary the Jew—and Zosimos credits her with the development of a broad range of apparatus and techniques. Maria’s techniques include a method of gentle, even heating using a bath of hot water rather than an open flame. This simple but useful invention preserved the legacy of Maria the ancient alchemist, not only for the rest of alchemy’s history, but even down to the present day. It is her name that remains attached to the bain-marie or bagno maria of French and Italian cookery.

Several of the pieces of apparatus Zosimos describes—for example, one called the kerotakis—are designed to expose one material to the vapors of another. Indeed, he seems particularly interested in the action of vapors on solids. This interest is partly grounded on practical observations. Ancient craftsmen knew that the vapors released by heated cadmia (or calamine, a zinc-containing earth) could turn copper golden by transforming it into brass (an alloy of zinc and copper). The vapors of mercury and arsenic whiten copper to a silvery color. Perhaps knowledge of these color changes induced Zosimos to seek analogous processes that would bring about true transmutations. Guiding theories are certainly discernible in his writings. Today there is a common misconception that alchemists worked more or less blindly—stumbling about mixing a little of this and a little of that in a random search for gold. This notion is far from the truth; already with Zosimos we can identify theoretical principles that guided his practical work, as well as practical observations that supported or modified his theories. Many theoretical frameworks for alchemy would develop in various times and places, and these frameworks both supported the possibility of transmutation and suggested avenues for pursuing it practically.

Across the gulf of ages, Zosimos’s observant, active, questioning mind makes itself apparent. In one passage, he notices the disparate effects of sulfur vapor on different substances, and expresses his astonishment that while the vapor is white and whitens most substances, when it is absorbed by mercury, which is itself white, the resulting composition is yellow. Always ready to criticize his contemporaries, Zosimos chides them by saying that “they should inquire into this mystery first of all.” He likewise expresses his surprise that when the vapor of sulfur turns mercury into a solid, not only does the mercury lose its volatility and become fixed (that is, nonvolatile), but the sulfur also becomes fixed and remains combined with the mercury. Zosimos’s observation is now recognized as a basic principle of chemistry: when substances react with one another, their properties are not “averaged,” as they would be in a mere mixture, but are instead completely changed. Clearly, Zosimos was a careful observer who thought deeply about what he witnessed experimentally.