Here’s an extended version of my article in Chemistry World on the "Books of Secrets" exhibition currently at the Chemical Heritage Foundation in Philadelphia.
You thought your chemistry textbook can be hard to follow sometimes? Consider what a student of chemistry might be faced with in the early seventeenth century:
“Antimony is the true bath of gold. Philosophers call it the examiner and the stilanx. Poets say that in this bath Vulcan washed Phoebus, and purified him from all dirt and imperfection. It is produced from the purest Mercury and Sulphur, under the genus of vitriol, in metallic form and brightness. Some philosophers call it the White Lead of the Wise Men, or simply the Lead…”
This is a small part of the description in The Aurora of the Philosophers, a book attributed to the sixteenth-century Swiss alchemist and physician Paracelsus (1493-1541), for making the “arcanum of Antimony”, apparently a component of the “Red Tincture” or philosopher’s stone, which could transmute base metals into gold. It is, Paracelsus averred, a “very red oil, like the colour of a ruby… with a most fragrant smell and a very sweet taste” (which you could discover at some peril). The book contains very detailed instructions for how to make this stuff – provided that you know what “aquafortis”, “crocus of Mars” and “calcined tutia” are, and that you take care to control the heat of the furnace, in case (the author warns) your glass vessels and perhaps even the furnace itself should shatter.
All this fits the image of the alchemist depicted by Pieter Bruegel the Elder in a print of around 1558, which shows a laboratory in turmoil, littered with paraphernalia and smoky from the fire, where a savant works urgently to make gold while his household descends into disarray all around him. Bruegel’s engraving set the tone for pictures of alchemists at work over the next two centuries or so, in which they were often shown as figures of fun, engaged on a fool’s quest and totally out of touch with the real world.
Pieter Bruegel the Elder, The Alchemist (c.1558)
But that caricature doesn’t quite stand up to scrutiny. For one thing, despite all its arcane language that only fellow adepts would understand, Paracelsus’s experimental procedure is in fact quite carefully recorded: it’s not so different, once you grasp the chemical names and techniques, from something you’d find in textbooks of chemistry four centuries later. The aim – transmutation of metals – might seem misguided from this distance, but there’s nothing so crazy about the methods.
Second, the frenzied experimentation in Brueghel’s picture, in which the deluded alchemist commits his last penny to the crucible, is being directed by a scholar who sits at the back reading a book. (The text is, however, satirical: the scholar points to the words “Alge mist”, a pun on “alchemist” meaning all is failed, and we see the alchemist’s future in the window as he leads his family to the poorhouse.)
Books are ubiquitous in paintings of alchemists, which became a genre in their own right in the seventeenth century. Very often the alchemist is shown consulting a text, and even when he is doing the bellowing and experimenting himself, a book stands open in front of him. Sometimes it’s the act of reading, rather than experimenting, that supplies the satire: in a painting by the Dutch artist Mattheus van Helmont (no relation, apparently, to the famous chemist Jan Baptista van Helmont), the papers tumble from the desk to litter the floor in ridiculous excess. “The use of books and texts in alchemical practice may not be discussed frequently, but it becomes obvious when looking at the actual manuscripts used by alchemists and at the multitude of paintings that depict them”, says Amanda Shields, curator of fine art at the Chemical Heritage Foundation (CHF) in Philadelphia.
After David Teniers the Younger, Alchemist with Book and Crucible (c.1630s)
Mattheus van Helmont, The Alchemist (17th century)
The complex relationship of alchemists to their books is explored in a current exhibition at the CHF called "Books of Secrets: Writing and Reading Alchemy". It was motivated by the Foundation’s recent acquisition of a collection of 12 alchemical manuscripts, mostly from the fifteenth century. They were bought from a dealer after having been auctioned by the Bibliotheca Philosophica Hermetica, a private collection of esoteric books based in Amsterdam and funded by the Dutch businessman Joost Ritman. Among the new acquisitions was one of just six existing complete copies of the highly influential Pretiosa margarita novella (Precious New Pearl) supposedly by the fourteenth-century Italian alchemist Petrus Bonus. The CHF already possessed one of the most substantial collections of paintings of alchemists in the world, mostly from the seventeenth to the nineteenth centuries, and while being keenly aware of the difference between the dates of the books and the paintings, Shields and the CHF’s curator of rare books James Voelkel saw an opportunity to use these two resources to explore what books meant for the alchemists and early chemists: who wrote them, who they were intended for, who actually bought them, and how they were read.
Of course, there weren’t really any students of chemistry in the early seventeenth century. That discipline didn’t exist for at least another hundred years, and its emergence from alchemy was convoluted and disputed. Arguably the first real textbook of chemistry was Cours de chymie, published by the Frenchman Nicaise Lefebvre in 1660, who would have been identified by the transitional terms chymist or iatrochemist, the latter indicating the use of chemistry in medicine. Alchemy was still very much in the air throughout the seventeenth century: both Robert Boyle and Isaac Newton devoted a great deal of effort to discovering the philosopher’s stone, and neither of them doubted that the transmutation of metals was possible. But it wasn’t by any means all about making gold. In the sixteenth century just about any chemical manipulation, whether to make medicines, pigments and dyes, or simple household substances such as soap, would have been regarded as a kind of alchemy.
This is why the whole notion of an “alchemical literature” is ambiguous. Some writers, such as the late sixteenth-century physician Michael Maier, who directed alchemical experiments in the court of the Holy Roman Emperor Rudolf II in Prague, wrote about the subject in mystical and highly allegorical terms that would have been opaque to a craftsperson. Others, such as the Saxon Georg Bauer (known as Agricola), wrote highly practical manuals such as Agricola’s treatise on mining and metallurgy, De re metallica (1556). Paracelsus’s works, which became popular in the late sixteenth century (he died in 1541), were a mixture of abstruse “chemical philosophy” and straightforward recipes for making drugs and medicines. And aside from such intellectual writers both inside and outside the universities, during the Renaissance there arose a sometimes lucrative tradition of “how to” manuals known as Kunstbüchlein, which were hotch-potch collections of recipes from all manner of sources, including classical encyclopaedists such as Pliny and ill-reputed medieval books of magic. These often styled themselves as “books of secrets”, which of course made them sound very alluring – but often they were miscellanies more likely to give you a mundane recipe for curing toothache than the secret of how to turn lead into gold.
In other words, “secrets” weren’t necessarily about forbidden knowledge at all. According to historian of science William Eamon of New Mexico State University in Las Cruces, “the term was used to describe both trade secrets, in the sense of being concealed, and also “tricks of the trades,” in other words techniques.” Eamon adds that the word “secrets” also “carried a lot of weight owing to the medieval tradition of esoteric knowledge”, which remained prominent in the alchemical tradition of the Renaissance. This glamour meant that the term could be useful for selling books. But how could you allude to secrets while writing them down for all the world to read? Some writers argued that there was virtually a moral imperative to do so. In his introduction to the hugely popular Kunstbüchlein titled simply Secreti (1555), Alessio Piemontese (a pseudonym, probably for the Italian writer Girolamo Ruscelli) told an elaborate and perhaps concocted story of how, by withholding secrets from a physician, he had once been responsible for the death of the physician’s patient.
This tradition of compilations of “secrets” was an old one. The historian of experimental science Lynn Thorndike has suggested that “the most popular book in the Middle Ages” might have been a volume called the Secretum secretorum or “Secret of secrets” (how much more enticing a title could you get?), which has obscure origins probably in the Islamic literature from around the tenth century. It was often attributed to Aristotle, but it’s pretty certain that he never wrote it – as with so many medieval books, the association with a famous name is just a selling point. The book does, however, reflect the Islamic writers’ enthusiasm for Aristotle, and as well as alchemy it includes sections on medicine, astrology, numerology, magic and much else. It was a kind of pocketbook of all that the scholar might want to know – in the words of one historian, a “middle-brow classic for the layman.”
But even if some of these “secrets” seemed hardly worth keeping, alchemy was different – for it really could seem dangerous. If it was possible to make gold, what would that do to the currency and the economy? It was largely this kind of worry, rather than any perception that alchemy was wrong-headed, that gave it a bad reputation. In 1317 Pope John XXII made alchemy illegal and imposed harsh sentences on anyone found guilty of trying to make gold. There was, however, also concern – some of it justified – that alchemists were swindlers who were duping people with fake gold. The image of the alchemist as a trickster who blinded gullible clients with incomprehensible jargon was crystallized in Ben Jonson’s 1610 play The Alchemist, in which his wily charlatan Subtle is a figure of fun. What’s more, alchemy was often associated with religious non-conformism. Paracelsus was unorthodox enough to upset all parties during the Reformation, but he was often linked to the Protestant cause and was sometimes called the “Luther of medicine.” When the French iatrochemists, who adopted Paracelsian ideas, battled with the medical traditionalists in the royal court at the end of the sixteenth century, the dispute was as much about religion – Catholics versus French Protestants (Huguenots) – as it was about medicine.
In view of all this, the genuine alchemist had to tread carefully until at least the seventeenth century. He was vulnerable to suspicion, ridicule and condemnation. That’s one reason why alchemical texts were often written with “intentional obscurity”, according to Voelkel. If you wrote cryptically, you could always argue your way out of accusations that you’d said something heretical or illegal. But the alchemical writers also felt that their knowledge held real power and so should be made unintelligible to lay people. A third motivation will be familiar to anyone who has ever read postmodernist academics: if you wrote too plainly, people might think that what you were saying is trivial, whereas if it was hard to understand then it seems profound and mysterious. Even if the recipes were straightforward, you wouldn’t get far without knowing the “code names” (Decknamen) for chemical substances: that “stinking spirit” is sulphur, and the “grey wolf” or “sordid whore” is stibnite (antimony sulphide), say.
Probably all of these motives for concealment and obfuscation were important to some degree, says Eamon – but he suspects that the major factor in the recondite character of many alchemical books was “to enhance the status and mystery of the work.” Also, he adds, “one shouldn’t underestimate the sheer inertia of tradition: secrecy was a very ancient tradition and always connected with that idea of initiation. Its hold over alchemy was strong even after there was little need for it.” Even Robert Boyle, whose The Sceptical Chymist has often been misinterpreted as a dismissal of all of alchemy rather than just its mystical and cryptic excesses, “employed elaborate coding devices to conceal his recipes”, Eamon says – especially those involved in gold-making. Despite insisting that adepts should be less obscure and cagey, Boyle wasn’t averse to it himself. “He may simply have protecting his reputation”, says Eamon - he didn’t want to be associated with an art many regarded as foolish. Isaac Newton, whose notebooks attest to extensive alchemical experimentation, was similarly guarded about that work.
The alchemist’s library
Given the diversity of sources, what would an alchemist have had in his library? The answer would depend somewhat on the kind of alchemy (or chymistry) they did, says Eamon. “The more practically inclined alchemists would probably have owned few books,” he says, “and they would probably have been heavy on books on metallurgy such as Agricola’s De re metallica and works such as the Kunstbüchlein.” Alchemists who were more interested in gold-making and the more esoteric mysteries of the art “would have been drawn to works such as those of [the pseudonymous] Basil Valentine, one of the more celebrated chemists of the period, such as The Triumphal Chariot of Antimony.” The medieval texts attributed to the Arabic writer Jabir ibn Hayyan (Latinized to Geber) would also have been popular among this sort of alchemist, Eamon adds.
Alchemists who wrote about distillation, such as the Frenchman John of Rupescissa and authors who wrote under the name of the Spanish philosopher Ramon Llull, were popular in the sixteenth century, especially for alchemists mainly interested in medicine. “Works by Paracelsus and his followers would also be represented in the chymist’s library”, says Eamon. “For many alchemists, books of secrets would also have been quite useful, of which the most popular was Alessio Piemontese’s Secreti.”
The English writer John Evelyn claimed of Robert Boyle that he learnt “more from men, real experiments, & in his laboratory… than from books”. But in fact Boyle had a very large library that included many alchemical works. “Unfortunately the library was dispersed after Boyle’s death and no library catalogue exists,” says Eamon, “but historians have been able to identify several of his books from his notes.” These included, for example, Agricola’s De re metallica and works by Johann Glauber, Paracelsus and Daniel Sennert. Newton’s library is much better catalogued, and included well-used copies of Paracelsus’s On the Transmutation of Metals and an English translation of Novum lumen chymicum by the Moravian Paracelsian alchemist Michael Sendivogius.
A dialogue in the lab
The CHF exhibition shows that such alchemical books weren’t at all treated like sacred texts. While they were still hand-copied these books could cost a fortune, but that didn’t mean they were kept in pristine form. They are well thumbed and evidently much used, sometimes showing signs of a benchtop life just as the later paintings imply. One book, a collection of recipes from Italian and English sources dated around 1470-75, has pages begrimed with what looks like soot. When the conservator used by the CHF, Rebecca Smyrl at the Conservation Center for Art and Historic Artifacts in Philadelphia, offered to remove the offending substance, Voelkel implored her not to, for he figured that this might be the debris from an actual experiment.
Cooked in the furnace: are these soot stains in a fifteenth-century alchemical text the debris from use in the lab?
What’s more, the readers scribbled all over the pages. Since paper itself was expensive, you might as well use the original text as your notebook, and margins were left deliberately generous to accommodate the annotations. In a copy of Christophorus Parisiensis’ Opera from 1557 there is not a square centimeter wasted, and the notes are recorded in a neat hand almost to tiny to read without magnification. Readers didn’t just mine the book for information: they engaged in a dialogue with the author, making corrections or arguing about interpretations. “There was a real conversation going on”, says Erin McLeary, director of the CHF museum. These markings attest that the books were anything but status symbols to be filed away ostentatiously on the shelf. “Reading was a huge part of alchemical practice”, says Voelkel.
The pages of a sixteenth-century alchemical book with marginal notes from a reader.
The CHF’s newly acquired manuscripts are particularly revealing because they date from the moment when print culture was emerging. The printing press lowered the financial and practical barriers to book ownership. “It made alchemical books widely available and relatively affordable”, says Eamon. “You can already see the decline of the notion of books as luxury items in the early sixteenth century.” Printing enabled the Kunstbüchlein artisan’s manuals to become bestsellers in the early sixteenth century: “they were cheaply printed, widely translated, and produced in large numbers”, says Eamon. Alessio Piemontese’s Secreti went through over 100 editions, and its likely author Ruscelli seems to have been something of a hack (the polite term was poligrafo) churning out whatever his publisher demanded. Print culture drove the trend of writing books in vernacular languages rather than Latin (which many potential buyers couldn’t read), and this opening up of new audiences was exploited as much by religious dissenters – Martin Luther was one of the first to spot the possibilities – as by publishers of scientific tracts, such as the Aldine Press of the Venetian humanist Aldus Pius Manutius.
The transition is fascinating to see in the CHF’s books. The early typefaces were designed to look like handwritten text, and some of the abbreviations used by scribes, such as the ampersand (&) were carried over to print – in this case with the origin as a stylized Latin et still evident. Some early printed books left a space at the start of chapters for the ornate initial capital letters to be added by hand. Quite often, the owners decided to save on the expense, so that the chapters begin with a blank.
As time passed and alchemy turned into chymistry and then chemistry, the image of the alchemist recorded by the painters became more tolerant and less satirical. In the hands of one of the most prolific and influential artists of this genre, the Antwerp-born David Teniers the Younger (1610-1690), the alchemist is less Breugel’s foolish agent of chaos and more a sober laboratory worker. If his floor is still strewn with vessels of brass, glass and clay, that’s simply because it allows Teniers to show off his skill at painting textures. In The Village Chemist (1760) by Justus Juncker, the physician sits calmly taking notes in his well-lit study-workshop; François-Marius Granet’s The Alchemist (early 19th century) shows a sober, monk-like figure in a spacious, sparsely furnished chamber; and Charles Meer Webb’s The Search for the Alchemical Formula (1858) makes the alchemist a romanticized, Gothic savant.
But what are they all doing? Reading (and writing). The text was always there.
François-Marius Granet, The Alchemist (early 19th century)
Charles Meer Webb, The Search for the Alchemical Formula (1858)
W. Eamon, Science and the Secrets of Nature (Princeton University Press, 1996).
L. M. Principe & L. DeWitt, Transmutations: Alchemy in Art (Chemical Heritage Foundation, 2002).
L. M. Principe, The Aspiring Adept (Princeton University Press, 2000).