Citrination and its Discontents: Yellow as a Sign of Alchemical Change

Abstract

Many of the “signs and tokens” described in alchemical texts relate to colour, from the Crow’s Bill signifying putrefaction to the philosophical solvents disguised as Green Lions, Red Dragons, and Grey Wolves. While the process of yellowing, or citrination, often appears in medieval recipes, it seems to have interested commentators less than the more familiar processes of blackening, whitening, or reddening. Yet beyond these canonical colours, yellowness turns out to be ubiquitous in alchemy and its associated craft practices, both in Latin texts and vernacular translations. This paper uses source criticism and experimental reconstruction to interrogate the role of yellowness at the beginning, middle, and end of practice, focusing on fifteenth- and sixteenth-century England. As starting ingredients, yellow vitriol and litharge offered the potential for transmutation but also posed problems for identification and preparation. As an intermediate stage, yellowness offered promising signs of future success, in the form of dramatic colour changes and unexpected products. But yellowness also offered an end in itself, as appears from the many citrination processes attested in recipe collections which aimed to imitate the properties of gold – suggesting that yellowing was prized as a significant indicator of chemical change across diverse areas of craft practice.

Introduction

Sometymes black, sometymes was he redd,

Now like ashes, now Citrine of Colour:

Now of Safforne hew, now sanguine was his head,

Now white as a lylie he shewed him in his bower.¹

Change in colour was serious business for the medieval alchemist. As matter shifted from one state to another, practitioners paid close attention to visible, outward signs – especially colour – that might correspond to deeper, structural changes in the matter under examination. From terse, anonymous recipes to philosophising tracts attributed to major authorities, alchemical writings primed readers to observe and interpret even the most fleeting alterations in the colour of materials; transient phenomena that they often described as “signs” or “tokens.” This preoccupation with visible signs extended to the elaborate cover names used to disguise alchemical processes and materials, from the “Crow’s Bill” that signalled putrefaction, to the array of Green Lions, Red Dragons, and Grey Wolves whose names hint at their identities as philosophical solvents made from specific ingredients.

In this paper, I argue that alchemical practitioners trained themselves through both reading and practical experience to identify and replicate the chemical phenomena – the signs and tokens – described in their written sources. One of the most problematic of these effects was citrination: a term that generally indicated the process of becoming yellow, but which also served as a euphemism for the yellowing of base metal into gold during alchemical transmutation. The term citrinitas (from citrinus, the colour of a lemon or citron) served as a substitute for gold in both practical recipes and visual, allegorical representations of alchemical processes. At the same time, all that yellowed was not gold. Practitioners often observed curious, yellowing effects which they did not elide with metallic gold, but which they still chose to record, even in cases where the effect did not obviously alter the value of the matter being worked upon. Their value lay instead in their role as signa – the term often rendered by English translators as “signs and tokens.”²

Successful reproduction of authoritative signa suggested that practitioners were on the right track, encouraging them to persevere in practice. The ability to recreate an effect described in a text also cemented practitioners’ faith in their authorities. Tokens could be used to convince sceptics, and to demonstrate the practitioner’s technical prowess to their audiences, including prospective patrons. They might range from straightforward, primarily visual effects, such as colour changes, to complex, multi-sensory assemblages. John of Rupescissa, for instance, in his influential treatise on the quintessence of wine (1351/2), describes several tokens for identifying the quintessence: it floats on the surface of denser liquids and emits a fragrance so appealing that, if it is placed in a corner of the house, visitors will be attracted towards it.³ Another striking example is the growth of a mercurial “tree” within the glass; an effect described in alchemical writings from the fifteenth century on, and reproduced in modern times by Lawrence Principe on the basis of a seventeenth-century process.⁴

Citrination offers a useful case study for examining such chemical tokens precisely because yellow failed to accrue serious philosophical or symbolic significance as an alchemical colour in its own right; that is to say, once disentangled from its metallic alter-ego, gold. Among the familiar Decknamen it is unusual to find any that specifically evoke yellow as a colour distinct from gold.⁵ And although yellow pigments are used in visual imagery to depict a variety of substances and allegorical figures, these yellows tend not to suggest specific and consistent symbolism except in the case of obvious analogues for gold, such as the sun (Figure 1). They are seldom pinned to a particular alchemical stage, process, or ingredient – certainly not to the extent enjoyed by other, “canonical” colours, such as black (associated with putrefaction) or red (associated with the completion of the work).

FIGURE 1 Extensive use of yellow pigment in a copy of the Ripley Scroll by Leonard Smethley, made in 1624. The tree and its occupants are not coloured yellow in earlier copies of the Scroll. By permission of the Princeton University Library.

Drawing on both textual sources and experimental reconstruction, this paper traces how yellowing processes were first set down in late medieval alchemical texts, and later interpreted and recreated by sixteenth-century English practitioners.⁶ Practical texts, in contrast to more theoretical works, abound with references to yellow ingredients, yellow products, and surprise appearances of yellow in the midst of other operations. In part, these observations reflect the vast profusion of yellow ingredients and products available to pre-modern artisans, from pigments and dyes to drugs and culinary ingredients. In the context of alchemy, for instance, practitioners were well acquainted with the bright yellow of sulphur and orpiment (arsenic sulphide), as well as the host of yellow plants, from saffron to celandine, that also appear in alchemical recipes, sometimes as literal ingredients but also as Decknamen for mineral substances. These contexts were not exclusive – the London astrologer and alchemist Simon Forman filled hundreds of manuscript pages with texts on gold-making, but he also included saffron, orpiment, gold, and massicot (a lead oxide) in a list of pigments “for yellow.”⁷

Yellowing was more than a descriptor, it was also a dynamic process. For English practitioners like Samuel Norton (1548–1621), Clement Draper (ca. 1550–1620), and Edward Kelley (1555–1597/8), the moment of becoming yellow was a visible sign, a necessary precursor to more substantial change that could be observed across multiple chemical operations.⁸ Calcining minerals yielded a range of yellows, from metal oxides like massicot, litharge (another lead oxide), and crocus martis (crocus of iron, a calcined iron oxide), to a yellow form of vitriol (iron sulphate; see below). Distilling organic matter produced yellow-coloured waters and oils, often with medicinal uses.⁹ Yellow was also associated with the making of mineral acids, as when distilling a citrine “water” from a mixture of vitriol, saltpetre, and other ingredients.¹⁰ And heating silver with various chemical preparations tincted it yellow, to the extent that “citrination” eventually became synonymous with the imitation of gold.

While transmutational alchemists were in no danger of mistaking these changes in colour for actual gold, they nonetheless paid close attention to yellowing effects, often recording their appearance as citrinus rather than the more generally used flavus (golden or reddish yellow).¹¹ Yellow remained ubiquitous in alchemical practice, even as written authorities increasingly downplayed the colour’s theoretical significance except in connection to gold. One reason, I argue, is that citrinitas was still valued as a token of successful practice even as it became marginalised in theory: a source of evidence that practitioners may have found personally validating, but which also stoked the confidence of their readers, thereby cementing their own authority.

The decline of citrinitas in alchemical philosophy

The status of yellow as a primary or secondary colour fluctuated in ancient and medieval thought, an ambivalence already apparent in Aristotle’s Meteorology and On the Senses.¹² This uncertainty seems to have inflected Latin alchemical thinking, especially in the “philosophical” sections, or theoricae, of treatises, where yellow (as distinct from gold) was described in increasingly disparaging terms throughout the fourteenth and fifteenth centuries. This decline contrasts with the colour’s earlier prominence in the Graeco-Roman tradition, where yellowing (xanthosis) was considered to be one of four major colour stages.¹³ From these late antique roots, Latin alchemists eventually inherited the fourfold colour progression of black (nigredo), white (albedo), yellow (citrinitas or citrinatio), and red (rubedo).¹⁴ Yet this fourfold system failed to adequately account for innovations in theory and practice, as techniques central to Greek chemistry were first supplemented and then superseded by new approaches.¹⁵ While the trifecta of black, white, and red remained a prominent feature in Latin theoretical texts and visual imagery, the identity and prestige of citrinitas as a major alchemical colour began to fade, as yellowing was variously conflated with the final reddening stage (an approach that treats red as an intensified form of yellow), or else downgraded as a “false” or transient step on the way to more lasting change.¹⁶

Yellow’s very proximity to gold may have hastened its downfall as a philosophically-respectable hue. The fourteenth and fifteenth centuries witnessed increased interest in alchemical activity, not only among scholars but also in courtly and ecclesiastical circles where excitement about the potential of cheaply-transmuted bullion was tempered by concern over fraud and currency crime. This period also witnessed the first popular satires of alchemy, as poets from Petrarch to Chaucer recounted the various tricks supposedly employed by fraudulent practitioners.¹⁷ Against that background, turning metals yellow became a suspect activity that could easily (and perhaps, on occasion, rightly) be interpreted as the falsification of gold.

We can map the changing status of citrinitas across several of the foundational works of alchemy written during the early fourteenth century, including major treatises attributed to Arnald of Villanova, John Dastin, and Raymond Lull. For instance, the question of whether there are three or four principal colours receives significant attention in the pseudo-Lullian alchemical corpus. Although not written by the historical Lull, these treatises were instrumental in shaping alchemical theories and practices as they developed through the fourteenth and fifteenth centuries. Yet we can detect a certain ambivalence with regard to citrination even in two of the earliest works of the corpus, the Testamentum and Codicillus, fourteenth-century treatises that make extensive use of concepts and diagrams drawn from authentic Lullian philosophy.¹⁸

This tension is not immediately obvious. The fourfold colour scheme is, in fact, a central tenet of the Codicillus, which introduces the “demonstrative general principles” of alchemy – that is to say, signs that inhere in material principles and that are known to skilled practitioners. These demonstrative principles, or signs, comprise “four principal colours”: black, white, citrine, and red. These are substantial colours from which all other, accidental colours can be derived through mixing.¹⁹ Furthermore, each of these four colours will physically manifest over the course of alchemical practice:

so that by knowing them, the careful workman may know how to administer that which, through demonstrable signs from nature, he will learn through practice, so that by following the given rule of the art he may know how to govern the matter.²⁰

This passage establishes the notion that colours were natural “signs” (signa), that practitioners must learn from their authorities and recognise in their practice. For the writer of the Codicillus, citrination still ranks among the four canonical colour changes, indicating both a substantial colour and a natural sign to guide attentive alchemists through the intricacies of the work.

Curiously, yellowing occupies a far less prestigious position in the earlier Testamentum. The writer of this substantial treatise, whom I shall refer to (following Michela Pereira) as the Magister Testamenti, claims that there are only three principal colours: black, white, and red.²¹ As in the Codicillus, these colours are important visible markers for the practitioner, indicating the achievement of specific chemical states: thus “when the blackening appears, it is a sign of the most noble corruption.”²² Yellow (citrinus) is mentioned only later in the text, and apparently as an intermediate rather than a principal colour. It is, in fact, a compound colour caused by the mixing of whiteness and redness – a notion that the Magister seems to have borrowed from another important theorica, the Rosarius philosophorum (incipit “Iste namque liber”) pseudonymously attributed to the Montpellier physician Arnald of Villanova.²³

In the Rosarius, Pseudo-Arnald uses white and yellow to refer specifically to silver, gold, and the two kinds of sulphur used to make them. Since gold requires the longest digestion, an alchemist must be capable of making silver (which requires a white sulphur) before he can move onto gold (which calls for a red one, and further digestion). Accordingly, the citrine colour, which is “compounded of much white and the purest red,”²⁴ must follow white:

For citrination is nothing other than perfect digestion, nor is whitening other than the removal of blackness. For heat acting in the moist first brings about blackness, and acting in the dry it produces whiteness, and in the white, citrinity.²⁵

The Magister Testamenti follows this passage closely, warning that citrine cannot be made until the white stage is completed: “seeing that no good citrine can be made from black until it is well whitened. For citrinity is caused by, and is essentially made from much white and just a little clear red.”²⁶ Importantly, however, the Magister omits Pseudo-Arnald’s references to gold and silver, as well as the practical context of preparing red and white sulphurs. As a result, the Testamentum seems to promote a more abstract progression of colours from black to white to yellow, while partially conflating citrinity with redness in a way that privileges the rubedo stage. The Magister’s preference for redness is evident elsewhere. When Pseudo-Arnald says that citrination is “perfect digestion,” he alludes to the making of gold, the most perfectly digested metal. The Magister replaces yellow with red, advising his readers that “this reddening is nothing else but complete digestion.”²⁷ However, he immediately follows this claim with a striking analogy that also associates yellow with digestion, and hence (by extension) with redness:

For when I rise from bed in the morning, if my urine is white and undigested then I know that I slept too little, and I return to bed to sleep. And when it happens that my urine is a citrine colour, then the heat of natural fire is extended and diffused through all of its urinary parts: by which nature clearly reveals that citrination is complete and perfect digestion.²⁸

Drawing an analogy between his matutinal observations and alchemical practice, the Magister concludes that a slow process of purification, cooking, and digestion is necessary to extract white and red sulphur from fine silver and gold. Yet his example also elides yellow with red – replacing red, which would clearly be inauspicious in the context of micturition, with the yellow colour typical of healthy urine. In this example, yellow therefore represents redness rather than marking a distinct alchemical process like the three other major colours. Yellow provides an intermediary step: a hue positioned somewhere between white and red, and hence capable of taking on the qualities of either of these “principal colours” as circumstance requires. In particular, the Magister seems to view yellow and red as closely related, at least in the context of digestion, an elision already observed in the Greek and Arabic alchemical traditions.²⁹

A similar ambiguity over the role of yellow can be detected in another of the foundational works of fourteenth-century alchemy, a Rosarius philosophorum with the incipit “Desiderabile desiderium” (The Desired Desire) often attributed to the English monk John Dastin.³⁰ The author – who is unlikely to have been the historical Dastin, but whom I shall here refer to as “Dastin” for the sake of narrative convenience – draws on both Pseudo-Arnald and Pseudo-Lull for his own account of citrination, and hence runs into the difficulty of reconciling several mutually contradictory texts. At first he seems to follow the Codicillus, by including yellow as one of “four principal colours.”³¹ But further examination reveals that Dastin did not view all of these colours as equal, with yellow occupying a decidedly inferior position.

For instance, Dastin paraphrases a passage already quoted above from Pseudo-Arnald, which positions citrine as a middle term between white and red, and hence as a necessary step towards attaining the rubedo. Dastin, however, alters his source to present citrine as a mixture of white and black:

No one can cross from the first to the third, except through the second; thus there is no crossing from the black to the citrine except through the white, because citrine is compounded of much white and very little black. Therefore unless this medicine is first whitened, you cannot made true red.³²

This bold substitution (present in manuscript copies as well as the printed edition cited here) severs the close association between yellowness and redness already present in the Arnaldian Rosarius, resulting in much more ambivalent melding of nigredo and albedo – a combination that evokes a colour closer to ashy grey than golden or reddish yellow.

The mystery deepens as Dastin turns to the Magister’s analogy with human digestion. He starts by borrowing the same anecdote about urine that we have already encountered in the Testamentum, which uses citrinity as an analogue for redness.³³ Taking the simile a step further, Dastin draws on the principles of Galenic medicine to observe that food is first digested in the stomach to make chyle, which is then further processed in the liver to make blood: “for as the first digestion in the stomach makes everything white, so the second in the liver makes everything red.”³⁴ Accordingly, after the appearance of a white colour inside the vessel, practitioners should augment their fire to bring about redness – although this colour may not appear immediately. Instead, a citrine colour will appear between white and red, “but this colour is not stable,” since once it has been observed, “the red shall not delay its coming.”³⁵ The appearance of this transient, unstable yellowness is therefore valueless except as a sign to the alchemist to keep working, reassured that he is close to obtaining the desired rubedo.

George Ripley’s “falce citryne”

This profound ambivalence concerning the place of citrinity, already apparent in the most influential alchemical theoricae of the fourteenth century, would culminate more than a hundred years later in the writings of the English alchemist and Augustinian canon George Ripley (fl. 1470s). Although yellow plays many and diverse roles in Ripley’s alchemical practice, the prestigious role of “principal colour” is not among them. Ripley mentions citrine only once in his famous English poem, the Compound of Alchemy (1471), when he groups it with other intermediate or unsatisfactory colours in his “Recapitulation of the Whole Work”:

Pale, and Black, wyth falce Citryne, unparfyt Whyte & Red,

Pekoks fethers in color gay, the Raynbow whych shall overgoe.³⁶

Not only does Ripley downplay the status of yellowness in the Compound, he seems to actively reject it as a principal colour, even in cases where rhetorical coherence demands a fourth colour. For instance, the “Wheel” diagram that Ripley appends to the Compound is designed around a series of quaternities, ranging from compass points to seasons and bodily humours. While the Wheel does include four colours, the fourth is not yellow but “pale,” a label that suggests a pallid, ashy colour.³⁷ Possibly Ripley had noted a correlation between alchemy and the horses of the four apocalyptic Horsemen in the Book of Revelation: white, black, red, and a fourth, ridden by Death, that is pale in hue.³⁸ A few years later, in his influential Medulla alchimiae (1476), Ripley plotted the alchemical colours onto the seasons of the year, an analogy that once again calls for four colours. Here Ripley skips from the summery albedo to the autumnal rubedo with only a slighting reference to yellow:

But when a white colour begins to appear, like the eyes of fishes, it may be known that summer is near; whom autumn will auspiciously follow with ripe and long-awaited redness, after ashy and citrine colour.³⁹

This disdain for citrinity appears in other works associated with Ripley, extending into vernacular works like the Accurtations of Raymond, a Middle English treatise that circulated widely under Ripley’s name. One recipe describes how to turn ceruse (white lead) to the “good colour of orpyment,” here indicating a strong red.⁴⁰ Heated, the ceruse will first turn a purple colour, but when the fire is increased “then will come a yelowe colour of no value.” The practitioner should make a stronger fire until the substance turns to a colour as red as vermillion, which “will not fayle.” Once again yellow appears as a mere waystation on the high road to red.

Although the yellow colour is valueless in itself, it has another role to play in the recipe – one that can be easily overlooked if we focus only on theoretical underpinnings or final ends. Together with the earlier purple stage, the yellow colour in the Accurtations offers a chemical signpost to practitioners: a marker that indicates whether they are on the right path and will eventually obtain their goal (in this case, a lasting red colour that can be used in further alchemical operations). This emphasis reminds us of Dastin’s encouragement to practitioners in the Desiderabile desiderium, to keep working even after producing yellowness rather than the hoped-for red. If they persevere, Dastin urges, the true colour will eventually come through. It appears that Ripley, who often quotes from Dastin and the Desiderabile, took this advice to heart, demoting yellow from the status of principal colour to that of a useful marker, or token, attesting to the validity of the process as a whole. It is therefore to the world of alchemical practice, rather than theory, that we now turn.

Signs of readiness: calcining vitriol

As we have seen, Ripley followed the theoretical trend by decisively rejecting citrinitas as a “canonical” colour stage in alchemy. Yet yellow appears at many other points throughout his practice, including at the start of the work. Ripley’s recipes for the transmuting mineral stone typically begin with the preparation of various solvents, or “fires”: in particular, a “natural fire” made by dissolving base metals in distilled vinegar, and a “fire against nature” made by subliming mercury with vitriol and saltpetre.⁴¹ In each case, his practice could be said to originate with a yellow, or yellow-ish, substance. One of the ingredients of natural fire is red lead, itself a product of yellow-orange litharge, discussed below. As for the corrosive fire against nature, its manufacture calls for vitriol: not the familiar blue or green varieties (copper and iron sulphate, respectively), but the much less well known yellow vitriol. Citrinity therefore features at the very beginning of Ripley’s practice.

Although Ripley’s interest in vitriol is well attested, his attention to yellow vitriol has not previously been noticed. We can infer it from one of his most substantial, yet little studied, works: the large compendium of recipes and treatises that together comprise the Bosome Book (ca. 1470), a manuscript that, while no longer extant in its original form, survives in numerous copies and translations dating from the 1570s onwards.⁴² The Bosome Book is packed with recipes that start by mixing Roman vitriol with other salts. Rather than using vitriol in its natural state, Ripley repeatedly directs his readers to first dry it out – usually by calcining or parching it (torrefactum) over a soft fire or hot coals – to bring it to another colour. Sometimes this colour is given as citrinus, allowing a relatively straightforward identification as yellow or citrine. More often, however, the word Ripley uses is glaucus, a term that usually designates a grey or greyish-white, but which several medieval English writers (including Bartolomaeus Anglicus, Robert Grosseteste, and Roger Bacon) also used to denote yellow.⁴³ This linguistic slippage creates problems not only for translation, but also for practice. Thus one recipe, titled simply “Vitriolum,” instructs that vitriol should “be calcined until it is ‘yellowed' [glaucescat].”⁴⁴ But is a yellowing process indeed what Ripley intends, or might glaucescat here indicate something closer to “brightening”? Might it even overlap with the ambiguous colouration that he elsewhere calls “ashy” or “pale”? To compound the problem, in a handful of recipes Ripley describes the effect of drying and heating vitriol more explicitly as citrinati (citrined), suggesting that a yellow colour is anticipated.⁴⁵

Certainly the identity of glaucus caused difficulties for Ripley’s later translators, who rendered the problematic term in various ways. The Bristolian alchemist Samuel Norton, who translated the entire Bosome Book into English around 1573 with a view to presenting it to Queen Elizabeth I, usually translates the term as a “shining” colour.⁴⁶ Roger Howes (fl. 1590s), on the other hand, who produced a separate translation of the Book in 1593, sticks to “yellow.”⁴⁷ For instance, Ripley’s recipe for Magna philosophorum corrosiva (The Philosophers’ Great Corrosive) starts with one pound of Roman vitriol “dried in glaucum colorem over a light fire.”⁴⁸ In translating this process, Norton follows his usual preference by rendering in glaucum colorem as “into bright shining colar.”⁴⁹ For Howes, the vitriol is made “into a yellow culler.”⁵⁰

In another recipe, Ripley describes a “philosophical” version of corrosive sublimate of mercury, a substance usually made by distilling vitriol, saltpetre, and mercury together in a vessel:

The sublimation of mercury with vitriol is done philosophically when our menstruum is put upon vitriol evaporated in glaucum and circulated in turn, until the matter on the surface whitens and dries into a crystalline species.⁵¹

In his translation of this passage, Norton moves even further from a “yellow” interpretation, describing the vitriol as “evaporated into bright white shyning.”⁵² Yet even Norton does sometimes recognise glaucus as denoting a golden colour. For instance, in the recipe Ad aurum alchemicum (For Alchemical Gold), Ripley again uses glaucus for the colour change:

Take therefore a good quantity of burning water, well rectified, and in it dissolve Roman vitriol, thoroughly “yellowed” [glaucescat] by calcining on the fire with evaporation of its superfluous wateriness.⁵³

This time, departing from his usual translation practice, Norton describes the vitriol as “well vapoured on the fire untill it be of golden colour shyninge.”⁵⁴

How can we explain the variety of translations of this single term, glaucus? Since Norton elsewhere claims to have tested Ripley’s recipes through his “owne severall practise,” one solution is to look for an answer in practical results.⁵⁵ In cases where an experiment generated a yellow-coloured vitriol, Norton may have allowed this result to inflect his translation, while retaining the more colour-neutral adjective “shining” for an outcome closer to white or grey. A complicating factor here is that the most commonly encountered forms of vitriol are not yellow at all, but blue (in the case of copper-rich vitriol) or green (iron-rich vitriol). The effect of heating it over coals, as Ripley’s recipes direct, will be determined by the proportion of metals in the vitriol, which in turn depends on where the vitriol is sourced from.

For instance, a nearly pure iron-based vitriol, green in colour, can indeed be yellowed by heating alone, provided the fire is at exactly the right temperature. Too soft, and the vitriol turns ashy-coloured but not yellow. Too hot, and it darkens to a red that is almost black.⁵⁶ However, copper-rich vitriol does not calcine to yellow in this way – it would first turn a greyish-white colour and then blacken on further heating; an effect that accords better with the traditional sense of glaucus than with citrinus.

Sometimes only practical experience can suggest an answer, and it is at moments like these, when textual sources alone cannot supply a clear answer, that the methodology of experimental reconstruction proves its worth – in this case, by applying our practical experience of calcining vitriol to fill lacunae in Ripley’s written accounts. This knowledge helps us to identify Ripley’s intended ingredient. In his most detailed description of Roman vitriol, in the Medulla alchimiae, Ripley states that it must be “green and azoqueus, which is not artificial but natural, that is to say, the droppings of copper.”⁵⁷ While clearly associating his vitriol with copper, Ripley’s reference to a green colour suggests iron-rich rather than copper-rich vitriol. Coupled with laboratory knowledge, this indicates that Ripley must have had access to a fairly pure sample of iron sulphate, since too much copper would not permit yellowing through heating alone.

While this looks like a straightforward solution to our identification problem, how can we be sure that is it the correct, or only, one? In this respect experimental reconstruction offers another service to researchers, by allowing us to speculate beyond the letter of the text. For there is a second way of making yellow vitriol that is easier and less risky than the dry calcination inferred from the Bosome Book, and which has the added advantage of working even with an impure mix of green and blue vitriol. This solution arises from an overlooked feature of Ripley’s recipes: namely, he always specifies that the vitriol changes colour as it dries, whether over coals or a soft fire – in some cases, as we have seen, with explicit mention of evaporating off “its superfluous wateriness.” But does that wateriness come from within the vitriol, or is it possible that the substance has to be moistened first?

Here I am indebted to my colleagues in the Department of Chemistry at Bologna, Marianna Marchini and Giacomo Montanari, for suggesting an experiment as simple as it is effective. They proposed dissolving the vitriol crystals in water to see what happened, using a vitriol made from half iron and half copper. Sure enough, within just a few hours the colour of the solution began to change: first to a greenish colour, and finally, after two days, to an unambiguous yellow (Figure 2). As the water began to evaporate off (a process that would of course be hastened by Ripley’s suggestion of gentle heating over coals), crystals of pale yellow vitriol started to form (Figure 3).

FIGURE 2 Vitriol (iron and copper sulphate) turns yellow in water. Copyright Marianna Marchini.

FIGURE 3 “Yellow vitriol” made by evaporating off the water from a solution of iron and copper sulphate. Laboratory of Dr Lucia Maini, University of Bologna. Copyright of the author.

The making of yellow vitriol by dissolution, all but forgotten to modern chemistry, represents a splinter of lost tacit knowledge from the late fifteenth century.⁵⁸ A simple step towards preparing the work’s starting ingredient, the dissolving of vitriol may have seemed so obvious to Ripley that he did not consider it worth stating. Despite the change in hue, yellow vitriol retains the chemical properties of its “natural” form, with the result that it can still be used to make such familiar products as mineral acids and corrosive sublimate. In Aristotelian terms, the primary change is to its accidental rather than its substantial qualities. While we cannot be certain which of the two techniques Ripley actually used, the existence of multiple options casts new light not just on the original recipes, but also on the interpretative options available to subsequent readers.

Given the chemical similarities between yellow vitriol and its greenish parent, we might ask why Ripley troubled to yellow it at all. Why not simply leave the vitriol in its natural state? Further work on yellow vitriol may reveal telling changes that contribute to our understanding of this practice and the choices it embodies. Until then, it seems likely that the wider connotations of yellow – its brightness, its proximity to the colour of gold – may have weighed in its favour. Ripley knew, of course, that the lemon-colour of yellow vitriol did not approach the metallic shine of gold. At the same time, practitioners must surely have been struck (as we were in the laboratory) by the transformative colour change; an indication, perhaps, that the original substance has been “purified” by its passage through water and fire. At the start of a practice that relies on using the best and purest ingredients, Ripley may have determined that a yellow vitriol, rather than blue or green, offered the most auspicious starting point for his alchemical work.

Ripley may also have noted another feature of vitriol’s yellowness – its transience. The citrinity of yellow vitriol prepared using the water method depends on the persistence of water molecules within its crystalline structure even after the solvent water has evaporated. On further heating, the water of crystallization is lost and the yellowness with it, fading to an ash-grey colour. While a dramatic starting point for the work, vitriol’s citrinity does not linger; a transience that perhaps underlies Ripley’s seeming ambivalence towards a colour that he describes in recipes as both glaucus and citrinus; in the Medulla as an “ashy and citrine colour”; and in the Compound as “falce Citryne.” It also casts Samuel Norton’s translation dilemma in a new light, as Ripley’s Elizabethan follower sought to accurately replicate a process in which both text and practice were fraught with ambiguity.

Signs of progress: kindling lead

Ripley’s yellow vitriol is not the only striking appearance of citrinity in his oeuvre. In the course of his work distilling lead compounds, he noticed that heating powdered black lead caused the lead to ignite into a glowing golden colour, an effect that we would now attribute to the oxidization of metallic lead into litharge. For Ripley’s early modern readers, however, this striking effect offered more than a casual observation. It was a sign or token that marked satisfactory progress along the alchemical path. While no practitioner would have mistaken this easily-replicated effect for genuine transmutation, the ability to elicit a brilliant yellow colour from the darkness of lead prompted both wonder and speculation in early modern audiences.

Colour changes offered especially powerful tokens in the context of practice, a fact already recognised by Ripley’s fourteenth-century authorities, including later works in the pseudo-Lullian corpus – among them, the pseudonymous author of the hugely influential Liber de secretis naturae, seu quinta essentia, who declared that “colour is a sign to the worker for the mastery of the whole work.”⁵⁹ Dastin, too, emphasised the relationship between signs and technical mastery, noting the importance of both careful observation of colour changes and a natural philosophical understanding of their causes:

Third, the fire is to be strengthened until [the matter being worked upon] is made citrine and very red: however if you were negligent of these colours in the working, you will see nothing. Therefore when you are in the work, study all the signs [signa] which appear in every decoction, to put away in your mind, and search out their causes, because this is very necessary to the qualified artisan to the completion of the whole work.⁶⁰

Dastin also followed his authorities in turning to a particular chemical observation – the changing colour of lead when heated – to illustrate how signa might work in practice. It was already well known that various treatments of lead produced a variety of colours, ranging from powdered black lead to white ceruse, and from yellow-orange litharge to orange-red minium. These colours can be produced using various methods and in various sequences. For instance, litharge is made either by oxidizing lead (black to yellow) or by decomposing ceruse (white to yellow), while further heating of litharge in a reverberatory furnace produces minium (yellow to red).⁶¹ Such transformations provided a useful and easily replicated analogue for the more profound colour changes effected by alchemical decoction, as expounded in the pseudo-Arnaldian Rosarius: “And this can even be observed in the calcination of lead, which is changed into black ash, afterwards into white, then into abundant red.”⁶² The Dastinian Desiderabile silently borrows from this passage: “for the heat working in the moist first generates blackness, and in the dry is worked whiteness, just as is seen in lead, when minium is made from it.”⁶³

Although Dastin ignored the yellowing of lead in his example, in keeping with his generally dismissive attitude towards citrination, later practitioners continued to pay close attention to this arresting colour change. If anything, the citrination of lead increased in importance as lead-based practices received renewed attention during the fifteenth century. Ripley, in particular, did much to popularise the use of lead compounds in his own alchemical writings, since he used “red lead” as a Deckname for his preferred prime matter, a mixture of lead and copper compounds that, when dissolved in distilled vinegar, provided the essential ingredient for his “vegetable stone.”⁶⁴ Ripley was also aware of the value of colour changes as signs of future success, especially in relation to the nigredo, which he referred to as a “token” on several occasions.⁶⁵

Unsurprisingly, lead features prominently in Ripley’s Bosome Book, often disguised by cover names like “Adrop” or “sericon.”⁶⁶ In one extended practica, “Recipe Adrop,” Ripley describes the calcination of finely-divided black lead, made by dry distilling sugar of lead (modern lead acetate) to draw off a white vapour, leaving black dregs in the bottom of the vessel. Characteristically, Ripley does not use citrinus to describe the resulting effect, but our old friend, glaucus: “Then take the first black faeces, and let them be calcined in a soft fire for the space of a quarter of an hour until they become of a ‘yellow' colour [glauci].”⁶⁷

As reconstruction shows (Figure 4), the meaning of Ripley’s glaucus must have been immediately clear to anyone familiar with the dramatic yellowing initiated by this practice. However, Ripley’s process – which in the Book is mentioned only briefly, half-buried in the middle of a longer recipe – benefited from some unexpected promotion at the hands of one of its translators. As I have argued elsewhere, Samuel Norton plugged a gap in another of Ripley’s laconic practicae by splicing the process with a different recipe attributed to an alchemist known as “Master Ive.”⁶⁸ In Ive’s version, the black faeces are ignited not by heating over fire, but by contact with a hot coal. Norton’s spliced-together text – the same version that was eventually printed under Ripley’s name – reads as follows:

Then take all the rest of the aforesaid black Feces or black Dragon, and spread them somewhat thin upon a clean Marble, or other fit Stone, and put into the one side thereof a burning Coal, and the Fire will glide through the Feces within half an Hour, and Calcyne them into a Citrine Colour, very glorious to behold.⁶⁹

FIGURE 4 Spontaneous “citrination” of black lead over heat. Laboratory of Professor Lawrence Principe, Johns Hopkins University. Copyright of the author.

As the evocative wording suggests, the outcome of this procedure is a far more dramatic and impressive effect than that originally described by Ripley, as the golden colour slides implacably across the dark surface of the lead, transforming it into a striking orange-yellow (Figure 5). Certainly Norton seems to have been intrigued by the effect, since he refers to it again in his own treatise, the Key of Alchemy (1573) dedicated to Elizabeth I, where he explicitly credits Ripley with its invention: “followe this way of Ripley, take of the first blacke earth and calcine it till it be fayr and yellowe.”⁷⁰

FIGURE 5 The “gliding fire” prompted by a hot coal. Laboratory of Dr Peter Wothers, University of Cambridge. Copyright of the author.

This process quickly caught on in Elizabethan England as copies and translations of Ripley’s Bosome Book spread among alchemical cognoscenti. Around this time, the golden-orange “calcination” of lead began to appear in alchemical treatises, recipes, and annotations to earlier works – not as evidence of transmutation, but as an intriguing chemical token worthy of mention. Thus the cosmographer Richard Eden, another devoted reader of Ripleian alchemy, describes the appearance in the bottom of his flask of “A turfe or tofte of blacke earth, which if you spreade or bruse [it] vppon a stone, and put a burninge cole therto, the fyer runneth all ouer it like tynder & burneth it red.”⁷¹ One of the most famous alchemical practitioners of the sixteenth century, Edward Kelley, went so far as to insert a reference to the gliding fire into the Work of Dunstan, a manufactured treatise based on the Ripleian Accurtations of Raymond.⁷² This passage describes a black earth that remains in the vessel after distilling sugar of lead, which on exposure to air “will be kindled of its own accord, and calcine itself marvellously.”⁷³

Kelley may have hoped that, by planting this token into the text, he would later be able to impress patrons by reconstructing an effect seemingly associated with Saint Dunstan, an important (if pseudonymous) figure in the English alchemical tradition. This invented history received a further twist when the Work of Dunstan was translated back into English, giving a new lease of life to Ripley and Norton’s gliding fire. While those authors are not, of course, mentioned in the doctored Work, the link may have been spotted by the alchemical scribe Thomas Robson, who copied out the entire Work alongside Norton’s Key. The English version relates the by-now-familiar yellowing effect, while linking it to yet another famous token, the Crow’s Bill:

Recipe the feces lefte in the bottome as sone as they be cold, for they are the crowes bill much blacker then pitch, which you may kindle with a burning Coole, that of ther owne accord they may be Calcined into a most yellowe earth.⁷⁴

What made the gliding fire such a notable token was not the colour change alone (a well known property of litharge) but its combination with other features peculiar to the fine, pyrophoric powder produced by distilling sugar of lead. Norton, Eden, and Kelley, all writing in the context of patronage, chose to emphasize distinctive aspects of the transformation: for Norton and Eden, the gliding or tinder-like effect of the citrination following the application of a hot coal; for Kelley, the lead’s ability to kindle “of its own accord.”

In the absence of these unique features, the changing colour of lead seems not to have been viewed as alchemically significant, insofar as we can tell from other accounts. Thus the popular Work on Saturn, attributed to the Dutch alchemist Isaac Hollandus, gives a fairly straightforward description of the calcination of lead (the “Saturn” of the work’s title), noting that it will remain in the bottom of the vessel “in a Masse or Lumpe; or else in dust or Powder of a yellow russett or darke redd, much like [th]e shell of a Pomegranett, or of Honye.”⁷⁵ The English alchemist William Blomfild, too, was more pragmatic than effusive when directing his readers to “Calcine your Lead thus,” by melting lead in a crucible over strong fire, and stirring with an iron rod until it “will come to an yellowe dust.”⁷⁶ Identification rather than spectacle is the object of such matter-of-fact accounts, as one man’s sign becomes another’s chemical commonplace.

Signs of completion: imitating gold

So far I have discussed yellowing primarily as a token of change, or demonstrative principle, in the specific context of metallic transmutation. In these alchemical texts, the final goal of practice is not a temporary or accidental yellowing, but citrination of another kind – the radical transmutation of base metal into a lasting gold. In this context, the value of an intermediate colour stage depends on its transience, as a temporary marker soon to be superseded by newer, better colours and forms. Achieving a durable yellow too early would bring the quest for transmutation to a premature end.

Such transience was less appreciated in other artisanal settings. In a host of crafts, from textile dyeing to pigment making, durable yellow was not viewed as an intermediate stage but as the desired end of practice. In particular, yellowing was an essential step in practices aimed at making a stable, artificial gold colour, as appears from the numerous recipes for golden inks and metallic surface effects that survive in late antique papyri.⁷⁷ Such imitative practices continued to flourish alongside alchemical procedures throughout the Islamic and Christian Middle Ages. By the sixteenth century, enterprising practitioners had access to an enormous variety of yellowing (or, more accurately, goldening) practices, from the pursuit of a universal transmuting agent capable of producing authentic gold, to scores of particularia intended to produce imitative surface effects.

A sample of the recipes gathered by the merchant Clement Draper during his imprisonment for debt in London’s King’s Bench Prison conveys the flavour and diversity of these particularia.⁷⁸ The practices shared by Draper’s informants, who included both fellow prisoners and sources from outside the Bench, offer a remarkable cross-section of the alchemical and metallurgical knowledge circulating in sixteenth-century England. They include many recipes for yellowing metals, often labelled as “citrinations.” Typically these involve applying a mineral mixture to silver in order to “citrine” it to the colour of gold – citrine here functioning as a verb rather than an adjective, and signifying a metallic, golden colour rather than the bright, mineral yellow of sulphur, orpiment, or crocus of iron.

For instance, one anonymous recipe for a “good citrination” begins with silver, which is first prepared with mercury, then gradually mixed with vitriol, sal ammoniac, alum roche, and “smith’s water.” Steel is then added, ground as thin as the back of a knife, and the mixture is boiled for a day and a night. If the resulting colour is unsatisfactory, the silver can be amalgamated with fresh mercury and the process repeated “till [th]e culler please you.”⁷⁹ Three drams of silver “so cittrined” are then melted with two drams of fine gold and a small piece of antimony to make an alloy that will pass as gold.

A similar approach to citrination appears in a recipe attributed to “[th]e Lerde of Markeston in Scotlande” – probably Sir Archibald Napier (1534–1608), Laird of Merchiston and general of the Scottish mint.⁸⁰ This process starts with white copperas, a term that might denote either natural white vitriol or a prepared vitriol of the kind we have already encountered, here calcined to white rather than yellow. This is made into a corrosive lye with sal ammoniac and verdigris, which, according to Napier, when heated with silver “dothe cittrine above all other.”

These recipes show that certain core ingredients tend to recur in the making of metallic yellowing agents, notably vitriol, sal ammoniac, and metallic compounds such as verdigris, aes ustum (burnt copper), and cinnabar. Other recipes bolster these mineral staples with ingredients from across the kingdoms of nature. For instance, “a citrination good and perfectly tested for gold,” copied from Sir William Bowper, starts with a strong lye made from the ashes of vine cuttings and lime, mixed with the urine of twelve-year old children or, alternatively, “men that drinke wyne.”⁸¹ The resulting lye is applied to a mineral mixture of salts, including sal ammoniac, sal alkali, vitriol, and verdigris, mixed with a little honey and distilled. This distillate is eventually absorbed by ground-up emery stone to make a powder, one ounce of which, cast upon six ounces of silver, “will make & cittrine it into good crowne gold.”

The framing of these recipes is very different from the alchemical practicae examined above, where yellow features primarily as a marker of progress towards making a transmuting agent. In citrination recipes there is no pretence that the silver has altered in substance, since true metallic transmutation is not the end of these processes. Rather, the value of the citrination depends on how closely it evokes the colour and shine of metallic gold – often with a clear hint that the metal, if properly citrined, will pass as genuine gold suitable for making jewellery, vessels, or even coin. Thus one “cittrination” (made from crocus of iron, burnt copper, sal ammoniac, and verdigris) specifies that the silver will attain the colour of 22-carat gold.⁸² Another procedure melts together silver, gold, and the usual set of mineral salts to produce a colour that will test as well as a gold coin on the touchstone.⁸³ And another, this time adding cinnabar to the salt mix, produces a “tincture of the sun” that, when cast onto silver, converts it into fixed gold capable of passing all trials, but “lacking in weight.”⁸⁴

Legally speaking, any practitioner who attempted to sell such artificially-yellowed metal in England would fall foul of a 1404/5 statute against metallic multiplication, designed to protect the coinage from debasement.⁸⁵ Citrination recipes nonetheless circulated widely, testifying to keen interest in such techniques among practitioners of diverse social backgrounds, including those who, like Napier, had an official interest in sourcing bullion and minting specie.

These recipes also offer a new perspective on the tokens recorded in alchemical practicae. During a citrination process, the signs that most accurately denote success are not intermediary effects, but final ones – indications that the citrined metal will convincingly pass as gold. Weight, quality of colour, and the ability to weather the touchstone and other trials are all signa of successful completion, convincing to the eye but also capable of withstanding the battery of assaying techniques available to early modern goldsmiths and mint workers. Such stable properties contrast with the eclectic array of less durable tokens set down in alchemical recipes, which, for all their interpretative difficulties, might still offer hope and reassurance to practitioners in the absence of actual samples of transmuted gold.

Conclusion: reconstructing alchemical signs

The double meaning of citrination, as both a temporary colour change and a means of falsifying metal, left its mark on alchemical literature. Anxiety about fraudulent, “multiplied” gold is already apparent in the critiques of non-metallic ingredients often found in alchemical theoricae, including those of Pseudo-Arnald, John Dastin, and George Ripley. In their theoretical writings (more so than in their practicae), Latin authorities excoriated the use of salts, vitriol, and a host of organic ingredients, a trope already present in Arabic alchemical writings where it fulfilled the same polemical purpose.⁸⁶ Such non-metallic ingredients could be discounted on philosophical grounds, but they are also, as we have seen, exactly the kind of ingredients that tend to flourish in citrination recipes, acquiring ever more dubious associations in the process. Citrination made metal appear golden; transmutation made metal gold. These processes were not the same.

Yet colours also instructed practitioners in how to work. The appearance of the right colour at the right time was a strong indicator, even in the absence of more concrete evidence, that practitioners were reading their instructions correctly. No colour – or the wrong one – might signify an inappropriate choice of starting ingredient, over-enthusiastic heating, or a failure of observation on the alchemist’s part. The observation of an anticipated yellowing effect, on the other hand, instilled confidence in both practitioners and their audiences: a marker of change that early modern alchemists, primed by their reading, learned to anticipate and record in their practice.

Learning to recognise and follow these chemical signposts was therefore an important aspect of doing alchemy, and one that continues to guide modern-day scholars who seek to replicate the practices described in written accounts. Reconstruction takes us beyond the letter of textual descriptions, foregrounding forgotten or misunderstood chemical effects by focusing our attention on details that might have been easily missed from reading alone. As my chemist collaborators and I learned from the case of water-yellowed vitriol, it is all too easy to pass over the significance – even the existence – of visual markers on the written page, especially in the terse and laconic environment of alchemical recipe literature. Of course, changes are easy to miss in practice as well, and careful observation is critical, especially in the case of a transient colour like yellow that might only be visible for the space of a minute, or a few seconds. The success of Ripley’s “gliding fire” rests partly on the ease with which it can be reproduced outside a sealed vessel, thereby making it accessible to multiple observers at once, garnering testimony and generating consensus. We no longer trust in signs and tokens to lead us to the philosophers’ stone, but through them we may, perhaps, discern the footsteps of the philosopher-practitioners who so avidly sought it.

Acknowledgements

I am grateful to my co-contributors in this special issue for invaluable comments on an early draft, and especially for the support and insight of Giacomo Montanari and Marianna Marchini while replicating Ripley’s vitriol recipes. Lawrence Principe, Peter Wothers, and Lucia Maini generously provided laboratory space, materials, and chemical expertise for experimental reconstructions. This work was supported by the award of an Innovation grant from the Office of the Dean for Research at Princeton University, and by a visiting fellowship at the Department of Philosophy and Communication at the University of Bologna, the latter funded by the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (GA 724914 - AlchemEast) and the joint FARE project AlchemEast in the West. Graeco-Arabic Alchemy in Western Europe (Italian Ministry of University and Research, project ID: R18W2STNE2). An early draft of this paper was presented at a workshop funded by the ERC under the European Union's Horizon 2020 Research and Innovation Program (GA 852732 - DURARE).

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Additional information

Notes on contributors

Jennifer M. Rampling

Jennifer Rampling is Associate Professor of History at Princeton University, where she teaches in the Program in History of Science. She is a former editor of Ambix, and author of The Experimental Fire: Inventing English Alchemy, 1300–1700 (Chicago, 2020). She is currently working on two book projects on alchemical imagery, including a history of the illuminated manuscripts known as “Ripley Scrolls.” E-mail: [email protected]

Notes

1 “The Worke of John Dastin,” in Theatrum Chemicum Britannicum, ed. Elias Ashmole (London, 1652), 257–68 (on 268).

2 See, for example, the sixteenth-century English translations of the Liber de secretis naturae, seu quinta essentia, British Library, MS Sloane 3707 (fols. 14v, 16r, and passim); Expositio Cantilenae, Bodleian Library, MS Ashmole 1508 (fol. 190v); and Stella complexionis, MS Ashmole 1459 72. The phrase “signs and tokens” also appears in vernacular texts, such as the Vegetable Work attributed to George Ripley (e.g. MS Sloane 3667, fol. 6v). On the multivalence of the Old English word ‘token,’ see Oxford English Dictionary, s.v. “Token.”

3 John of Rupescissa, De consideratione Quintae essentiae rerum omnium, opus sanè egregium (Basel, 1597), 27–28.

4 Lawrence M. Principe, “Apparatus and Reproducibility in Alchemy,” in Instruments and Experimentation in the History of Chemistry, ed. Frederic L. Holmes and Trevor H. Levere (Cambridge, MA: MIT Press, 2000), 55–74; Lawrence M. Principe, The Secrets of Alchemy (Chicago, IL: University of Chicago Press, 2013), 164–66.

5 On the place of yellowness in medieval culture more broadly, see Michel Pastoureau, Jaune: Histoire d’une Couleur (Paris: Éditions du Seuil, 2019); translated as Yellow: The History of a Color, trans. Jody Gladding (Princeton, NJ: Princeton University Press, 2019); Hermann Pleij, Colors Demonic and Divine: Shades of Meaning in the Middle Ages and After, trans. Diane Webb (New York: Columbia University Press, 2004); and the Introduction to this special issue.

6 On experimental reconstruction as a methodology in the history of alchemy and early modern chemistry, see Hjalmar Fors, Lawrence M. Principe, and Otto Sibum, eds., “From the Library to the Laboratory and Back Again: Experiment as a Tool for the History of Science,” special issue, Ambix 63, no. 2 (2016): 85–97. On reconstruction of craft practices more generally, Pamela H. Smith, From Lived Experience to the Written Word: Reconstructing Practical Knowledge in the Early Modern World (Chicago, IL: University of Chicago Press, 2022).

7 See Oxford, Bodleian Library, MS Ashmole 802, fol. 209v, where Forman also lists pigments suitable for making green, blue, red, white, and black. On Forman’s varied interests, see Lauren Kassell, Medicine and Magic in Elizabethan London: Simon Forman: Astrologer, Alchemist, and Physician (Oxford: Clarendon Press, 2005).

8 Chemistry was not, of course, the only field of knowledge to link the observation of visible signs to the “prognosis” of an operation. On the role of signs in scholastic medicine, see Ian Maclean, Logic, Signs and Nature in the Renaissance: The Case of Learned Medicine (Cambridge: Cambridge University Press, 2002).

9 On medical distillation techniques, see Tillmann Taape, “Hieronymus Brunschwig and the Making of Vernacular Knowledge in Early German Print” (PhD thesis, Pembroke College, University of Cambridge, 2017).

10 For instance, in the Rosarius minor attributed to “Hortulanus” in Theatrum chemicum, præcipuos selectorum auctorum tractatus de chemiæ et lapidis philosophici antiquitate, veritate, iure, præstantia et operationibus … , comp. Lazarus Zetzner (Ursel, 1602), vol. 2, 466–85 (on 478): “continua ignem lentum, donec alembicus intus colore citrino fit coloratus.”

11 Flavus is occasionally used for alchemical yellowing: thus Albertus Magnus, who usually prefers citrinus, uses flavus once to describe the superficial (as opposed to substantial) yellowing of metal: see Albertus Magnus, Book of Minerals, trans. Dorothy Wyckoff (Oxford: Oxford University Press, 1967), 176 n.7 (Wyckoff also notes here that Albertus’s favoured term for blue, blavus, was sometimes misread in printed editions as flavus). Edward Kelley, who also generally prefers citrinus, describes the yellowing of matter as “flavedine tingit” in Leipzig University Library MS 0398, fol. 124r. However, such instances are uncommon.

12 Aristotle implies in Meteorology, Book 3, that yellow may not be a “real” colour: thus, in rainbows “the appearance of yellow is due to contrast; for the red is whitened by its juxtaposition with green”; see Meteorology, trans. E. W. Webster, in The Complete Works of Aristotle, ed. Jonathan Barnes (Princeton, NJ: Princeton University Press, 1984), vol. 1, 603. On the complicated medieval reception of Aristotle’s colour theory, see Eric Kirchner and Mohammad Bagheri, “Color Theory in Medieval Islamic Lapidaries: Nıshābūrı, Tūsı and Kāshānı,” Centaurus 55 (2012): 1–19.

13 The usual order is melanosis (blackening), leukosis (whitening), xanthosis (yellowing), and iosis (purpling). For an early but thorough discussion, see Arthur John Hopkins, Alchemy: Child of Greek Philosophy (New York: Columbia University Press, 1934), 94–101. On links between yellow dyes and alchemy, see Caterina Manco and Matteo Martelli, “Is Gold Yellow? Plant Dyes and Gold-Making in the Ancient Chemical Arts,” in this issue.

14 This sequence is frequently acknowledged in secondary scholarship: see, for instance, Gareth Roberts, The Mirror of Alchemy: Alchemical Ideas and Images in Manuscripts and Books from Antiquity to the Seventeenth Century (London: British Library, 1994), 55–57.

15 Thus Hopkins argued in Alchemy that the fourfold scheme originally referred to a specific set of practices related to bronzing and colouring metal that arose in the specific context of Graeco-Roman Egypt. Interestingly, he supported his case using evidence from contemporary reconstruction; see Hopkins, “Bronzing Methods in the Alchemistic Leyden Papyri,” Chemical News 85 (1902): 49–52.

16 Centuries later, this decline was noted by the psychologist C. G. Jung in an oft quoted passage: “later, about the fifteenth or sixteenth century, the colours were reduced to three, and the xanthosis, otherwise called the citrinitas, gradually fell into disuse or was but seldom mentioned”; C. G. Jung, Psychology and Alchemy, trans. Gerhard Adler and R. F. C. Hull (Princeton, NJ: Princeton University Press, 1968), 333. Jung sought the answer in “inner psychological reasons,” rejecting a practical explanation for declining interest in citrination.

17 On alchemy, fraud, and satire, see Tara Nummedal, Alchemy and Authority in the Holy Roman Empire (Chicago, IL: University of Chicago Press, 2007); for alchemy and currency crime in England, see Jennifer M. Rampling, The Experimental Fire: Inventing English Alchemy, 1300–1700 (Chicago, IL: University of Chicago Press, 2020), 25–31.

18 On the pseudo-Lullian corpus, see Michela Pereira, The Alchemical Corpus Attributed to Raymond Lull (London: Warburg Institute, 1989); Pereira, L’oro dei filosofi: saggio sulle idee di un alchimista del Trecento (Spoleto: Centro Italiano di Studi sull’Alto Medioevo, 1992).

19 Codicillus, seu, Vade mecum Raymundi Lulli (Rouen, 1651), 11–12: “Demonstratiua principia generalia … sunt illa signa quae magis habitu fixo, materialibus principiis successiue in decoctionibus emittuntur, vt sunt quatuor principales colores, scilicet nigredo, albedo, citrinatio & rubedo: & ex illis emanant tot colores mixti per accidens, quot in tota natura excogitari poterunt, sed non remanent in effectu, nisi tantummodo quatuor supradicti colores essentiales veluti directores totius magisterij.” On this passage see also Pereira, L’oro dei filosofi, 142–43.

20 Codicillus, 12: “vt per illorum notitiam administrare sciat cautus artista, id de quo a natura per signa demonstrabilia cognoscet in practica, vt secundum regulam artis traditam, suam sciat gubernare materiam.”

21 Pereira, L’oro dei filosofi, 94.

22 Michela Pereira and Barbara Spaggiari, eds., Il Testamentum alchemico attribuito a Raimondo Lullo: Edizione del testo latino e catalano dal manoscritto Oxford, Corpus Christi College, 255 (Florence: Sismel, 1999), 58: “Verumptamen, fili, in mutacione lapidis attendes tres colores principales … quando apparebit nigredo, est signum corrupcionis multum nobilis.”

23 Arnald of Villanova [pseud.], Rosarius philosophorum, in Les oeuvres alchimiques attribuées à Arnaud de Villeneuve: Grand œuvre, médecine et prophétie au Moyen-Âge, ed. Antoine Calvet (Paris and Milan: S.É.H.A., Archè, 2011), 268–357 (hereafter Rosarius).

24 Rosarius, 284: “Non ergo potest fieri transitus de nigro ad perfectum citrinum nisi primo fuerit album, quoniam citrinum ex multo albo et purissimo rubeo est compositum.”

25 Rosarius, 284: “quoniam citrinatio nil aliud est quam completa digestio, nec albedo aliud est quam nigredinis ablatio. Calor namque agens in humido primo efficit nigredinem et agens in sicco operatur albedinem ac in albo citrinitatem.”

26 Testamentum, 58: “quoniam de nigro non potest fieri aliquod bonum citrinum, quousque sit bene album … Nam citrinitas causatur et est ex multo albo et pauco rubeo claro essencialiter.”

27 Testamentum, 60: “Ob hoc scias, fili, quod ista rubificacio non est aliud, nisi completa digestio.” Cf. n. 19, above. The colour red was closely associated with gold in both alchemical theory and craft practice more generally: see Smith, From Lived Experience to the Written Word, 83–87.

28 Testamentum, 60: “Qui dum a lecto in mane respicio, si mea urina est alba et indigesta, tunc cognosco, quod parum dormivi et repono me in lecto ad dormiendum. Et de facto urina citrinatur iccirco, quando calor ignis nature est extensus et diffusus per omnes suas partes urinales: per quod monstrat manifeste natura, quod citrinacio est completa et perfecta digestio. Et ideo potes recolligere quod sulphur album et rubeum habetur solummodo ab una materia metalli, / videlicet ab argento fino cum igne fini auri. Sed primo est necesse quod dicta materia sit fortiter depurata et cocta et digesta per modum differencialis.” On colours of urine in Graeco-Arabic medicine, see Lucia Raggetti, “The Humours and the Dyes: A New Witness to the Arabic Tradition of Galenic Summaries on Urine,” Nuncius 38 (2023): 397–443.

29 See the Introduction to this special issue.

30 (Pseudo-)John Dastin, “Rosarium, Arcanum Philosophorum secretissimum comprehendens,” in Bibliotheca chemica curiosa, ed. J.-J. Manget, 2 vols. (Geneva, 1702), vol. 2, 309–26 (hereafter BCC). On Dastin, see Lynn Thorndike, A History of Magic and Experimental Science, 8 vols. (New York: University of Columbia Press, 1923–1958), vol. 3, 85–102; W. R. Theisen, “John Dastin’s Letter on the Philosopher’s Stone,” Ambix 33 (1986): 78–87; José Rodríguez-Guerrero, “Un Repaso a la Alquimia del Midi Francés en al Siglo XIV (Parte I),” Azogue: Revista electrónica dedicada al estudio histórico crítico de la alquimia 7 (2010–2013): 75–141. The Desiderabile draws heavily on the Rosarius philosophorum of pseudo-Arnald of Villanova: see Antoine Calvet, Les oeuvres alchimiques attribuées à Arnaud de Villeneuve: Grand œuvre, médecine et prophétie au Moyen-Âge (Paris and Milan: S.É.H.A., Archè, 2011), 128–30.

31 BCC, 320.

32 BCC, 313: “nemo potest transire de primo ad tertium, nisi per secundum: sic non est transitus de nigro ad citrinum nisi per album, quia citrinum ex multo albo & paucissimo nigro est compositum; ideoque nisi hanc medicinam primo dealbaveris, verum rubeum facere non poteris.” Cf. BCC, 321.

33 BCC, 322.

34 BCC, 322: “nam prima digestio stomachi omnia dealbat, secunda vero hepatis omnia rubificat.” The Galenic theory of digestion was summarised in the widely-taught Isagoge ad Tegni Galieni of Hunayn ibn Ishaq al-Ibadi (Johannitius); for an overview, see Cornelius O’Boyle, The Art of Medicine: Medical Teaching at the University of Paris, 1250–1400 (Leiden: Brill, 1998), 83–86; Owen Temkin, Galenism: The Rise and Decline of a Medical Philosophy (Ithaca, NY: Cornell University Press, 1973).

35 BCC, 322: “medius tamen inter illos colores apparebit citrinus; sed ille color non est stabilis, quia post illum rubeus non moratur venire.”

36 George Ripley, “Compound of Alchymy,” in Ashmole, Theatrum, 88. The white and red mentioned here are not the true albedo and rubedo, but temporary and imperfect colour changes that Ripley warns of earlier in the poem.

37 Ashmole, Theatrum, 117 (fold-out). On the symbolism of Ripley’s Wheel, see Jennifer M. Rampling, “Depicting the Medieval Alchemical Cosmos: George Ripley’s Wheel of Inferior Astronomy,” Early Science and Medicine 18 (2013): 45–86.

38 Revelation 6:1–8. In the original Greek, the mount of the fourth Horseman is described as sickly green (chloros), a word translated in the Latin Vulgate as “pale” (equus pallidus). The pale horse is sometimes represented as yellow in medieval art.

39 George Ripley, Medulla alchimiae, Cambridge, Trinity College Library MS R.14.58, Pt. 3, fol. 3v: “Sed cum color albus instar oculorum piscium inceperit apparere: sciri poterit quam prope est estas quam post cinericium et citrinum cum matura et expectata rubedine autumpnus prospere insequetur.” See also Rampling, “Depicting the Medieval Alchemical Cosmos,” 71–72. The “eyes of fishes” (oculi piscium) are a common sign in medieval alchemical writings, seemingly indicating a whitish, pearlescent quality. When transcribing text from manuscripts, I have retained original spelling and capitalisation, using italics to denote the expansion of contractions or abbreviations. Information necessary to convey the sense of a word or passage (including the translation of symbols) is included within square brackets.

40 Bodleian Library, MS Ashmole 759, fol. 46v; cf. fol. 91r. Orpiment, a compound of arsenic, is usually yellow in colour; it is possible the author has confused it with realgar, a red arsenical compound.

41 On the two fires, see Rampling, Experimental Fire, 81–97.

42 On the Bosome Book, see Rampling, Experimental Fire, chaps. 3, 7, 8; Jennifer M. Rampling, “John Dee and the Alchemists: Practising and Promoting English Alchemy in the Holy Roman Empire,” Studies in History and Philosophy of Science (2012): 498–508.

43 The Dictionary of Medieval Latin from British Sources variously defines glaucus as: “grey, greyish-blue, silvery-grey”; “sparkling, shiny, brilliant”; and “greyish-yellow, yellow or orange.” On using glaucus to describe yellow in the late twelfth to thirteenth centuries, see Rolf Kuehni and Andreas Schwarz, Color Ordered: A Survey of Color Systems From Antiquity to the Present (Oxford: Oxford University Press, 2008), 28–30.

44 London, British Library MS Harley 2411, fol. 45v: “Torrifiat vsque glaucescat.”

45 E.g. MS Harley 2411, fol. 68r: “Trahe tincturam vitrioli Romani (super carbones) citrinati.”

46 On Norton’s translation of the Bosome Book, see Rampling, Experimental Fire, chap. 7.

47 Howes’ translation is in Bodleian Library MS Ashmole 766, Pt 3. It was copied several times by Thomas Robson. On Howes as a translator of alchemical texts, see Rampling, Experimental Fire, 262–63.

48 MS Harley 2411, fol. 54v: “Recipe Vitriol Romani dessicati in glaucum colorem super ignem lentum Libram vnam.”

49 British Library MS Sloane 2175, fol. 159r.

50 MS Ashmole 766, Pt 3, fol. 34r.

51 MS Harley 2411, fol. 39v: “Sublimatio [mercu]rij a vitriolo Philosophicae fit quando menstruum ponitur super vitriolum evaporatum in glaucum et circulantur invicem, donec materia in superficie dealbetur & desiccetur in speciem Crystallinam.”

52 MS Sloane 2175, fols. 158v–159r.

53 MS Harley 2411, fol. 24v: “Recipe ergo aquam ardentem bene rectificatam in bona quantitate, et in ea soluatur vitriolum Romanum bene vsque glaucescat torrefactum ad ignem cum evaporatione suas superfluae aquositatis.”

54 MS Harley 2411, fol. 37r. At another point, he explains that the vitriol used “to make aqua fortis to dissolve [gold] after .G[eorge]. R[ipley].” must be “vapered into Cytryne”: British Library MS Sloane 3667, fol. 170r. However, since the Latin version is not extant for this recipe, it is not clear whether his source text used glaucus or citrinus.

55 Samuel Norton, The Key of Alchemy, Getty Research Institute MS 18, vol. 10, pt 2, 8. See Rampling, Experimental Fire, 277–78.

56 In modern parlance, a red iron oxide. Ripley’s recipes tend to specify a softer heat, by placing over hot coals.

57 Medulla, fol. 3r: “vitriolum viride & azoqueum. hoc est non artificiale: sed naturale. scilicet stillicidium cupri.” Two centuries later, Nicolas Lémery (1645–1715) noted in his Cours de chymie (Paris, 1675) that both Roman vitriol and English vitriol were iron-based and green in colour. Nicolas Lémery, A Course of Chemistry Containing an Easie Method of Preparing Those Chymical Medicins Which Are Used in Physick …  (London, 1686), 330: “There are three sorts of Green Vitriol, the German, English, and the Roman … That of England partakes of Iron, and is proper to make the Spirit of Vitriol. The Roman is much like the English Vitriol, excepting that it is not so easie to dissolve.”

58 In chemical terms, dissolution causes some of the ferrous ions to oxidise into ferric ions, producing the distinctive yellow colour. Giacomo Montanari is currently preparing a scientific paper based on his investigations into the effects of dissolution on vitriol.

59 (Pseudo-)Raymond Lull, De alchimia opuscula (Nuremberg, 1546) fol. 81v: “Tamen k est ipsi artistae signum in magisterium totius operis.” The letter K here designates the colours of the work according to the author’s alphabetical scheme.

60 BCC, 314: “tertio fortificandus est ignis, quousque citrinum fiat & multum rubeum: verum si in operando negligens fueris, istorum colorum nihil videbis. Idcirco cum in opere fueris, studeas omnia signa, quae in qualibet decoctione apparent, in mente recondere, & illorum causas investigare, quia hoc multum necesarium est artifici idoneo ad totius operis complementum.”

61 The colours of lead compounds are well attested in both medieval and early modern sources: see, for instance, Albertus Magnus, Book of Minerals, 38–40, 211–12; Lémery, A Course of Chemistry, chap. 5.

62 Rosarius, 284: “Et hoc quidem in calcinatione plumbi attendi potest, quod convertitur in cinerem nigrum, postea in album, deinde in nimium rubeum.” This passage is closely cited in the pseudo-Lullian Codicillus, 133: “& hoc in calcinatione plumbi videtur, quod primo in cinerem nigrum vertitur, post in album, deinde in citrinum, & postmodum in rubeum.” Calcining lead would usually result in a progression from black-yellow-red, suggesting that Pseudo-Arnald has tweaked the usual order to fit the alchemical colour sequence expounded elsewhere in the text.

63 BCC, 315: “quod est signum solutionis verae: nam calor agens in humido generat primo nigredinem, & in sicco operatur albedinem, & in albo citrinatem, sicut est videre in plumbo, cum ex eo fit minium.”

64 On the identification of Ripley’s red lead, see Rampling, Experimental Fire, 92–97.

65 Ripley, Compound of Alchemy, in Ashmole, Theatrum, 133–34: “one token trew” (on Crow’s Head); “that tokyn call we” (on Crow’s Bill).

66 Jennifer M. Rampling, “Transmuting Sericon: Alchemy as ‘Practical Exegesis’ in Early Modern England,” Osiris 29 (2014): 19–34; Rampling, Experimental Fire, chap. 2 and passim.

67 MS Harley 2411, fol. 33r: “Tunc recipe primas faeces nigras, et lento igne per spacium 4tae partis vnius horae calcinentur vsque dum fiant coloris glauci.”

68 Rampling, Experimental Fire, 275–78.

69 “The Bosome-Book of Sir George Ripley, Canon of Bridlington. Containing His Philosophical Accurtations in the making the Philosophers Mercury and Elixirs,” in Collectanea Chymica: A Collection of Ten Several Treatises in Chymistry, concerning The Liquor Alkahest, the Mercury of Philosophers, and other Curiosities worthy the Perusal …  (London: for William Cooper, 1684), 101–21 (on 104).

70 Samuel Norton, Key of Alchemy, Bodleian Library MS Ashmole 1421, fol. 181r.

71 Cambridge, Trinity College MS R.14.56, fol. 88r. It is notable that Eden interprets the colour as red rather than yellow. Eden probably started compiling this manuscript while working on behalf of his patron, Richard Whalley: Rampling, Experimental Fire, 221–28.

72 As I argue elsewhere, Kelley used practices from the Bosome Book in East Central Europe to promote his reputation as an alchemical philosopher: Rampling, Experimental Fire, chap. 8; Rampling, “John Dee and the Alchemists.”

73 Leipzig University Library MS 0398, fol. 4v: “Hac ratione nigra illa terra sua Sponte incendetur, seque Calcinabit mirifice.” The same text, with some minor alterations, was later appended to the treatise published under Kelley’s name as the Via humida: Edward Kelley, Tractatus duo egregii, de lapide philosophorum (Hamburg: Schultze, 1676), 83. See Rampling, Experimental Fire, 311–12.

74 Work of Dunstan, MS Ashmole 1421, fol. 151v (in a chapter titled “Of the feces”).

75 “John Isack his Great worke of Saturne, Translated out of Flemmish,” in Bodleian Library MS Ashmole 1459, pt 2, 172. The Opus saturni was printed in German translation in Basilius Valentinus, Triumphwagen Antinomii, ed. Johann Thölde (Leipzig: Jacob Apel, 1604), 465–510; see Annelies van Gijsen, “Isaac Hollandus Revisited,” in Chymia: Science and Nature in Medieval and Early Modern Europe, ed. Miguel López Pérez, Didier Kahn, and Mar Rey Bueno (Newcastle-upon-Tyne: Cambridge Scholars, 2010), 310–30.

76 Bodleian Library MS Ashmole 1415, fol. 98r-v.

77 Matteo Martelli, “‘Alchemical’ Inks in the Syriac Tradition,” in Traces of Ink: Experiences of Philology and Replication, ed. Lucia Raggetti (Leiden: Brill, 2021), 79–104.

78 Draper compiled notebooks full of alchemical recipes, collected from diverse sources, while interred in the King’s Bench prison. See Deborah E. Harkness, The Jewel House: Elizabethan London and the Scientific Revolution (New Haven: Yale University Press, 2007), chap. 5.

79 “Citrinacio Bona,” British Library MS Sloane 3657, fol. 28r.

80 “A citrination,” MS Sloane 3657, fol. 30v. On Napier, see Julian Goodare, “Napier, Sir Archibald, of Merchiston (1534–1608),” Oxford Dictionary of National Biography, s.v.

81 “Citrinatio Bona et perfecta approbato per .[solem],” MS Sloane 3657, fol. 27v.

82 “A cittrination,” MS Sloane 3657, fol. 30r: “it wilbe a culler of 22 carrattis.” This seems to be the translation of a Latin “Citrinacio” on fol. 26v.

83 “For a citrinacion,” MS Sloane 3657, fol. 33v: “as highe [sol] as [th]e Ryall on the touche.” On the Henry VII gold ryal, see C. E. Challis, The Tudor Coinage (New York: Manchester University Press, 1978), 52 and passim.

84 “Tinctura solis,” MS Sloane 3657, fol. 29r: “et conuertit in Solem fixam, ad omnie Judicium sed defficit in pondere.” While the metal is said to “convert” into sol (gold), the weight deficit shows that this conversion was not viewed as true transmutation.

85 National Archives, Statutes of the Realm, 5 Henry IV, cap. IV; translated in D. Geoghegan, “A Licence of Henry VI to Practise Alchemy,” Ambix 6 (1957): 10–17. See also Rampling, Experimental Fire, 29–31.

86 See, for instance, Ashmole, Theatrum, 189–91.