IN 1460, ONE OF MANY book-hunting monks in the employ of the great Cosimo de Medici returned to Florence from a monastery in Macedonia with a nearly complete manuscript of the Hermes Trismegistus’s Corpus Hermeticum. Cosimo (who was already 70 years old, and knew he was close to death) eagerly gave it to his translator, Marsilio Ficino, hoping to be able to read it before he died. At the time, the Corpus Hermeticum appeared, Ficino had been preparing a translation of Plato, but Cosimo ordered Ficino to set the Greek aside and turn to the Corpus Hermeticum instead. Ficino’s translation would in turn develop a life beyond his patron; in the next 150 years, it would go through 16 editions and spread like wildfire through the early modern world.

So far, this story may sound a bit like the opening of The Swerve: How the World Became Modern, in which Stephen Greenblatt tells of another book-hunter, Poggio Bracciolini, whose lucky find of a manuscript of Lucretius’ mystical epic On the Nature of Things revolutionized the Renaissance and “made the world modern.” But Hermes Trismegistus, then as now, lacked the credibility of Lucretius. He was and remains a mythical figure: no historical record of an actual person named “Hermes Trismegistus” exists, nor is it clear who actually authored the various books attributed to him. Additionally, those books — consisting of several dozen texts on astronomy, magic, and philosophy from the fourth century A.D. — hold little interest for 21st century scientists or philosophers. But Hermes Trismegistus was important for another reason: he was credited by many as being the founder of alchemy.

Alchemy runs alongside the traditional narrative of Western thought like a shadow. Long ignored, often discredited as pseudoscience, it has nonetheless had important effects on the cultures of Europe and the Middle East for the past two thousand (or more) years. It’s always been a hermetic field of inquiry, sealed off from mainstream intellectual pursuits, but its traces linger. The phrase “hermetically sealed,” after all, derives from the “Seal of Hermes,” the nickname for the stopper on the long-necked glass jar used in making the Philosopher’s Stone (the substance that would allow for a direct transmutation of an impure metal like lead into the pure silver or gold). We have alchemists to thank for the French name for a double boiler, the bain-marie (bagno-maria in Italian) — a reference to another apocryphal alchemist, Maria the Jew, and her method of heating slowly using water — and for the fact that we refer to quicksilver as “mercury.”

Beyond this, not much of alchemy remains in our modern culture, and what we do know is often wrong. The comic scene in Sterne’s Tristam Shandy, where the protagonist’s father tries to name his son “Trismegistus” only to have the name miscommunicated and reduced to “Tristam” by a forgetful maid and an arrogant priest, offers as good a metaphor as any for the inconsistent transmission of the history of alchemy and its secrets through the ages.

The goal of Lawrence M. Principe’s The Secrets of Alchemy is to begin to retrace that history. Principe, a professor at Johns Hopkins, has been writing on alchemy for years; his latest is a distillation, as it were, of years of academic scholarship into a more generally accessible book. Accordingly, it aims to offer a “reliable guide to the various secrets of alchemy” rather than a comprehensive history, which would not only “run to unreadable length but would also be premature, since scholars still have much to learn about it.” And while we may know more about alchemy now than we did only a few decades ago, much of this information has been published in obscure specialist journals in various languages, with the result that the scholarship threatens to become as hermetic as its subject. In translating this work into a more accessible idiom, Principe has produced a work that is eminently readable and that sacrifices none of its critical edge or erudition (and one that features a heavy index and bibliography for those looking for more than its 200 pages has to offer).

Among the more fascinating aspects of Principe’s book is his recreation of various ancient alchemical recipes. In the Leiden Papyrus, which dates from the third century A.D. and is one of the earliest known collection of writings on alchemy, there is a recipe for “the water of sulphur,” which reads: “Lime, one dram: sulfur, previously ground, an equal quantity. Put them together into a vessel. Add sharp vinegar or the urine of a youth; heat from underneath until the liquid looks like blood. Filter it from the sediments, and use it pure.” Dipping a piece of polished silver into this concoction will result in a patination of the sulfides on the silver’s surface, resulting in a deep, reddish-golden color. Keep the silver in the mixture for long enough and it will seem, to an untrained eye, that you have turned silver into gold — though Principe notes that he found, after some trial and error, urine works far better than vinegar. (You have to admire an author who cooks with his own urine for the sake of research.) Less easy to replicate is a recipe for the Philosopher’s Stone from a 12th century monk named Theophilus, which calls for “Spanish gold […] compounded from red copper, basilisk powder, human blood, and vinegar.” In order to synthesize basilisk powder, which may not be readily available in some markets, Theophilus offers the following instructions: lock up two old roosters and overfeed them until they copulate and lay eggs. Give the eggs to toads, who will hatch them into chicks with serpent tails and will eventually mature into basilisks. The basilisks are kept in kettles buried underground and then incinerated, their ashes constituting the necessary powder. These two recipes — one relatively practical, one fantastic and absurd — represent the variety and difficulty of coming to grips with alchemy. Just when one might be convinced there’s serious science lurking somewhere behind it all, the alchemists put forward some fanciful assertion that is either metaphor, hearsay, lunacy, or some combination of all three.

At its best, alchemy was both a practical art, focused on the creation of gold and/or silver (a process known as “chrysopoeia”) and a larger theoretical approach to the world. As Principe explains, “Alchemy, like other scientific pursuits, is more than a collection of recipes. There must also exist some body of theory that provides an intellectual framework, that undergirds and explains practical work, and that guides pathways for the discovery of new knowledge.” Alchemy, in its true form, was less about gaining material fortune than it was about aligning oneself with greater principles; gold became the de facto aim not for its economic value but because it was thought the purest substance on earth. (Which is not to say that alchemy wasn’t often used as a cover for more dubious methods of getting rich quick. In the 16th century, Pope Leo X sent an emissary to Northern Africa, and among the reports he sent back was of the alchemists in the Moroccan city of Fez, who reeked of sulfur and gathered nightly to discuss their craft: “But their chiefest drift is to coin counterfeit money,” he wrote, “for which cause you shall see most of them in Fez with their hands cut off.”) Others still were eager to adapt the principles of alchemy towards Christian ends, as in an anonymous 14th century manuscript that used alchemy as a metaphor for divine transubstantiation: “Christ was the example of all things, and our elixir can be understood according to the conception, generation, nativity, and passion of Christ, and can be compared to Christ in regard to the sayings of the prophets.”

While the precise definition of alchemy is ever mercurial, the pattern that begins to emerge is one of more, not less ambiguity. This, too, was by design. Alchemy is built on dissembling, often in the form of decknamen, or “cover names:” various code words, allegorical symbols, and other obfuscating signs meant to confuse the casual reader. The fourth century alchemist Zosimos of Panopolis described how alchemists “call a single thing by many names while they call many things a single name”; likewise, the author of another text, attributed to the likely fictitious Abu Musa Jabir ibn-Hayyan, wrote: “my method is to present knowledge by cutting it up and dispersing it into many places.” As Principe notes, a “persistent problem facing historians of alchemy is figuring out if an author really is who he says he is, and if he lived when and where he claims. Anonymity, pseudonymity, secrecy, mysteries, false trails, and subterfuge fill the entire subject from beginning to end.”

It’s precisely the fact that alchemy is such an elusive target, and such a mélange of the practical and the ridiculous, the physical and the metaphysical, that makes Principe’s book so engaging. The Secrets of Alchemy is one of those rare books that, in the best possible sense, asks many more questions than it can answer, with each answered question suggesting a host of other lines of thought. Just as alchemists favored the Latin slogan, Liber librum aperit (“one book opens another”), so too does Principe’s book open up onto a labyrinth of other books, from the bizarrely titled alchemical treatises he discusses — On Apparatuses and Furnaces, On the Congelation and Gluing-Together of Stones, On the Consideration of the Fifth Essence of All Things, and The Book of the Secret of Secrets, to name just a few — to literary and scientific works like Dante’s Divine Comedy, Thomas Browne’s Religio Medici, Kepler’s Harmonices Mundi, Anthanasius Kircher’s The Magnet, and on and on.

The Secrets of Alchemy moves swiftly through the history of the practice, from its earliest Egyptian, Greek, and Roman origins, through to its adoption and development in the early medieval Arab world, and on to its rediscovery by Christian Europe in the High Middle Ages. Indeed, as Principe shows, this mystical science remained remarkably malleable in its ability to respond to issues of the day, and reveals its comprehensive impact on more respectable strands of philosophy and religion. This wide-ranging narrative complicates a traditional picture of history that we’ve become accustomed to from books like The Swerve, with its direct line between the Classical world and the Renaissance. In Greenblatt’s narrative of history, the period between the fall of Ancient Rome and the rise of early modern Florence was mostly a dead zone, a time of ignorant Christians, or, worse, Muslims, about whom little was known and even less said. (Greenblatt includes only one reference to Arabic culture in The Swerve, a footnote in which he discusses how they destroyed books.) The very etymology of the word “alchemy,” combining as it does the Arabic definite article “al-“ to the Greek cheo, “to melt or to fuse” rejects this prejudice, and any recognition of the stubborn influence of alchemy on the past two thousand years should dispel once and for all these over-determined and overly reductive narratives.

But the long tradition of willful obfuscation, of fraud, and of constant reinterpretations and misunderstandings surrounding alchemy explains why Principe, having moved chronologically towards the Early Modern Period, suddenly breaks this sequence, leapfrogging to the 19th century. He does this in order to debunk, in advance, many of the misconceptions surrounding alchemy that emerged in the past 200 years, which disrupt our ability to see clearly how the Early Moderns actually saw their own world. For starters, alchemy’s long association with con artists led to fundamental distortions about its true nature and made it the target of repeated attacks from intellectuals and theologians. In 1783 Christoph Martin Wieland, writing in the German Mercury, labeled gold-making “The ancient enemy of true wisdom”; another writer from the same journal, Johann Christian Wiegleb, denounced it as witchcraft. Meanwhile, the useful aspects of alchemy were spun off to form the basis of chemistry; any hint that they had emerged from the ancient art of chrysopoeia was gradually forgotten. Principe concludes: “This strategy proved remarkably successful at the time, and remarkably invisible by hindsight,” and it suggests that the history of respectable science is itself something of an alchemical process: impurities are extracted over centuries via cynicism and ridicule, resulting in only the pure, hard, real stuff.

Attempts to rescue alchemy’s reputation resulted in other problematic distortions. Mary Anne Atwood’s 1850 A Suggestive Inquiry into the Hermetic Mystery first put forward the idea that alchemical texts described not so much a physical process as a spiritual quest, an idea that gradually gained considerable traction; Carl Jung, for one, claimed in 1936 that alchemy “does not deal at all, or for the most part at least, with chemical experiments, but probably with something like psychic processes expressed in pseudochemical language.”

All of this may well be far off the mark, but if so, it’s because alchemy was a victim of its own success: its long history of evasion and dissemblance worked so well that later commentators couldn’t hope to understand its true intentions. These rhetorical distortions keep us from cutting through the muck of history to get at how the early moderns truly saw alchemy. Principe’s own home experiments confirm that not all of alchemy was fraudulent, and his historical research proves that it was never meant to be understood as an abstract spiritual journey. In his painstaking recreation of alchemical experiments (at least those that don’t involve basilisk powder), he confirms that the scientific knowledge was usually rigorous (at least on its own terms), and that the cryptic allegorical symbols employed by alchemists can, with some study, be decoded and made sense of. While he’s never able to turn lead into gold himself, he concludes that “at least some cryptic texts and emblems dealing with making the Philosopher’s Stone do encode real chemical processes that their authors carried out.” As for the “bizarre allegories and emblems […] [they] can be rationally and methodically deciphered, meaning that their authors constructed them carefully, not only to conceal their knowledge but also to reveal it in a measured way to the most talented and thus the most worthy readers.” In this way, then, alchemists may have anticipated the modernist aesthetics of writers like Pound, Eliot and Joyce, with their hermeneutic games of obfuscation and decipherment.

Principe’s book ends with two divergent, though not contradictory, conclusions. First: if alchemy fell into disrepute and misunderstanding, it was likely because it was too specialized to find a foothold in the modern world. Despite its long history, the study of alchemy never found a proper place in the university; further, few first-rate writers or philosophers ever fully embraced it. Sir Thomas Browne may have claimed that the search for the Philosopher’s Stone, “hath taught me a great deal of divinity, and instructed my beliefe, how that immortall spirit and incorruptible substance of my soule may lye obscure, and sleepe a while within this house of flesh,” but such an admission was an exception, not the rule. For the most part the writers who did approach alchemy approached it with scorn (such as Dante, who put alchemists in the eighth circle of Hell, along with other fraudsters) or ridicule (such as Ben Jonson, whose 1610 play The Alchemist savaged the practice and those foolish enough to fall for its claims).

Second, and more central: any study of alchemy reveals the stubborn fact that early modern thought was far more universalizing in its scope than our own age’s tendency to compartmentalize fields of knowledge, and approaching alchemy on its own terms means rethinking our own relationship to the intellectual past. Whereas we regard art, chemistry, religion, and philosophy as separate, discrete areas of study, the early moderns didn’t think like this. Alchemy blends together a variety of disciplines, methods, and philosophies, and any attempt to isolate its chemistry or its symbolism out from the rest is a willful misreading. As Principe stresses repeatedly, “premoderns tended to conceive of and visualize the world in multivalent terms, where each individual thing was connected to many others by webs of analogy and metaphor. This view stands in contrast to the modern tendency to compartmentalize and isolate things and ideas into separate disciplines.”

The lasting value of a book like this one is its reminder that we misunderstand the past because we constantly look for ourselves in it. We misunderstand alchemy because we expect it to conform to our current ideas of science, magic, and philosophy. “The significant links between alchemy and religion,” Principe warns, “might sometimes seem to mark it out as something alien from ‘science,’ but only if the comparison is made with reference to the science of our own day.” Alchemy remains a perpetual challenge to how we view the world, how we understand the divine and the natural world around us. And this is precisely why it remains important, and why any serious intellectual history — of science, of Europe or the Middle East, of the Renaissance — must take account of it. For, despite attempts by both mainstream scholars and alchemists to hermetically seal it off from the greater world, this fascinating chemical history continues to boil over, out of the shadows and into the light.

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