How to correct Plato, alchemically?

By Bojidar Dimitrov, AlchemEast Project

Jabir Ibn Hayyan is a figure of key importance for the development of alchemy and chemistry. A vast body of literature virtually covering the entire spectrum of ancient science has been attributed to the Islamic polymath, and yet much of the little we know about him remains shrouded in mystery. The very historicity of Jabir’s person and the authenticity of his works have been the subject of rigorous scholarly debate. This is largely due to the fact that the majority of the texts which belong to the Jabirian corpus have not been edited and published.

The scant biographical data provided by mediaeval Islamic sources and Jabir’s own works suggests that his lifetime spanned the period between ca. 721/725 and 812/815 AD. The so-called Jabir Problem mainly revolves around different aspects of this alleged historical context. The ambiguous relationship between the Arabic Jabirian corpus and the nascent alchemical tradition of the Latin West is the other major side of the conundrum. 

Paul Kraus’ ground-breaking studies on Jabir[1] proposed that the Jabirian corpus was probably compiled over a longer period of time by a school of alchemists who circulated their works under Jabir’s name. Similar doubts were already expressed by mediaeval Islamic scholars, and Kraus’ detailed analysis of the language and the content of seminal texts argues that the scientific terminology, doctrines and references to Greek authorities found in them point to a later stage of Islamic intellectual history, which began in the ninth century. Kraus’ conclusions have been debated by scholars since their publication in the 1940s, but the scope and depth of his research remain unmatched to this day.

One of the current objectives of the AlchemEast Project is to make available a collection of alchemical recipes belonging to a sub-genre of Jabir’s corpus. Plato’s Rectifications is the only surviving collection of a cycle of pseudepigraphical ‘rectifications’ associated with ancient authorities. The work is presented as a commentary on alchemical doctrines ascribed to Plato that the Greek sage is said to reveal to his disciple, Timaeus. The ninety recipes involve alchemical procedures with mercury which are intended to illustrate the application of Plato’s theories.

Socrates discussing philosophy with his disciples (from a thirteenth-century Arabic manuscript).

Jabir’s attribution of alchemical material to Plato is pertinent to the reception of Platonic influences in Islamic alchemy and the wider context of Islamic thought. While Jabir’s system incorporates key Neoplatonic traits of Greek philosophical alchemy, its experimental and arithmological developments are highly original and do not seem to derive from extant Greek texts. Furthermore, no alchemical texts are attributed to Plato (or Socrates) in the Greek tradition.[2] There are, however, Syriac recipes attributed to Plato, and he is generally accorded a prominent place in Arabic occult literature. Such facts may indicate that Jabir could have been influenced by late antique Neoplatonic traditions of a distinctly Near Eastern flavour.

An excerpt from Rectification Nr. 14 presents a recipe which involves the heating and cooling of mercury:

Then he said: take ten measures of spirit (i.e. mercury), put it in the middle gourd (i.e. glass vessel), and tighten upon it the alembic which has no aperture (i.e. valve). Heat it over gentle fire for ten days, then cool it off on the eleventh. Repeat the operation and gather the first water. The gourd containing mercury will be heated, or joined to the other gourd until it (i.e. mercury) dissolves in one of the two gourds. Take the thickened [residue], put it in the second gourd, and heat it until it melts, becomes liquid and turns red. Then heat the water until it boils and [the condensate] starts dripping all over the residue, [so that] it swells, absorbs some of the water and is incerated by it, and yields. It will become like wax, just as we described initially, and [even] better. If the procedure starts by heating the water until [the condensate] drips over the residue, it will be dissolved, and both will be dissolved, coagulated and incerated together, [and thus the procedure] is also complete. Peace.

Image 2: Depiction of alchemical apparatus with an alembic (MS, BNF Arabe 6915)

Depiction of alchemical apparatus with an alembic (MS BNF Arabe 6915).

The text exemplifies the fluidity of content that alchemical recipes often exhibit. The procedures it describes are relatively simple, but the textual variants in the manuscripts allow different possibilities. The translation above is not conclusive, since the relationship of the alembic and the two vessels is somewhat ambiguous. According to certain readings, for instance, the second vessel and the alembic must be alternated during the process of dissolution. The examination of further textual variants and manuscripts can expand our understanding of Jabir’s technical methodology. Ultimately, the intertextuality of Platonic pseudepigrapha found in Jabir and other traditions calls for an overarching discussion of Plato’s role in alchemical discourse. Whether this role was itself rectified by practitioners over the centuries, or the fluctuations we encounter in manuscripts are of a purely textual nature, are the main questions AlchemEast aims to address.

[1] Paul Kraus, Jābir ibn Ḥayyān. Contribution à l’histoire des idées scientifiques dans l’Islam, Vol. II. Jābir et la science grecque (Cairo: Mémoires de l’Institut d’Égypte 45.1, 1942).

[2] Ibid., p. 58.

Archaeology and early modern glassmaking recipes: The case of Oxford’s Old Ashmolean laboratory.

By Umberto Veronesi

Crystal blown bottle decorated with milk glass festoon (festoni di lattimo), c. 17th c., Venice.  Image courtesy of Wikimedia Commons.
Crystal blown bottle decorated with milk glass festoon (festoni di lattimo), c. 17th c., Venice. Image courtesy of Wikimedia Commons.

The product of human ingenuity, glass perfectly embodies the alchemical power to imitate nature by art and since the Bronze Age it has proved an incredibly hard substance to classify. Although glass only requires sand, salts and the action of fire, a quick look at any recipe collection will reveal that glassmakers have used a vast array of ingredients depending on what materials were available to them and on the physico-chemical characteristics desired. Colours and opacity were provided by the addition of the right metallic oxides, but even a perfectly colourless glass required specific reagents.[i]

Here, I am going to explore three 17th-century recipes for white enamels, what Venetians called lattimo. Enamels are glass pastes that could be coloured according to the need and then used as paint or to counterfeit gems. There are plenty of recipes out there, many are listed in Antonio Neri’ L’Arte Vetraria. However, in this post I am going to take my start from a different set of “primary” sources, namely the very crucibles used to manufacture white enamel at one of Europe’s leading chymical laboratories, the Old Ashmolean in Oxford. The residues found stuck to the walls of the vessels (Fig. 1) contain the chemical fingerprint of the ingredients used. The analysis of small cross-sections of such residues with a scanning electron microscope (SEM) are therefore a way to explore the recipes.

Figure 2. Crucible fragments analysed with glassmaking residues.
Figure 2. Crucible fragments analysed with glassmaking residues.

The chemical composition of the three residues shows both similarities and important differences. All of them have high levels of silica, corresponding to sand, the main component of glass. To melt silica a fondant is essential, and it needs to be added to the crucible. Here, two residues (B and C) bear the traces of a potassium-based fondant, probably saltpetre or even salt of tartar. Residue A has sodium oxide instead, which means that a different fondant was, pure soda most likely. Recipe-wise, this is the first relevant difference. Next, a reagent must also be added in order to render the glass paste white and opaque. A look at the microstructure of the residues (Fig. 2-4) helps identify what such reagents were and what different choices were made[ii].A (Fig. 2). The white aggregates visible in cross-section are the remnant of a mixture made of lead and tin calcined and then added to the crucible. This, together with somewhat large grains of sand, would produce the required colour and opacity.

Figure 3. SEM image of residue A showing dark sand grains and remains of lead-tin calx used as opacifying agent.
Figure 3. SEM image of residue A showing dark sand grains and remains of lead-tin calx used as opacifying agent.

B (Fig. 3). Here too crystals can be seen scattered throughout the glass and, like before, these are responsible for an opaque white enamel. However, these are made of tin oxide only, indicating that in this case the calx did not contain lead.

Figure 4. SEM image of residue B showing the tin oxide crystals as opacifying agent.
Figure 4. SEM image of residue B showing the tin oxide crystals as opacifying agent.

C (Fig. 4). There seems to be a third lattimo recipe being tested at the Old Ashmolean. This is more than a simple variant because it used a wholly different type of reagent, the antimony ore stibnite. The glass is indeed rich in antimony oxide while the microstructure reveals small white opacifying particles. These are a compound made of calcium and antimony that form when stibnite is added to the glass and heated. Such recipe is less common in technical writings, but it is reported in Christopher Merret’s commentary to Antonio Neri’s glassmaking treatise.[iii]

Figure 5. SEM image of residue C, showing the small opacifying crystals of calcium antimonate.
Figure 5. SEM image of residue C, showing the small opacifying crystals of calcium antimonate.

From this necessarily brief survey we can see that there is more than one way to make an opaque white glass paste. What is interesting is that such diversity happened at one of the leading chymical laboratories of its time, giving us an idea of the experimental nature of this enterprise. Making glasses was certainly a way of investigating nature, of looking at how transformations come about. At the same time, it was a way to test recipes for the industry. In this sense, artifacts can become a powerful tool for the history of recipes, another way to enter the arena of artisanal knowledge.

[i] Cable Michael 2001, p. 307.

[ii] Neri’s recipes for white enamel can be found in: Cable Michael. The world’s most famous book on glassmaking. The Art of glass by Antonio Neri, translated into English by Christopher Merrett (The Society of Glass Technology, 2001), Book 3.

[iii] For a general survey on glassmaking I suggest chapters from: Janssens Koen (Ed.). Modern Methods for Analysing Archaeological and Historical Glass, 2013.

Umberto Veronesi  is a Ph.D. candidate at the Institute of Archaeology, University College London. His dissertation entitled, “The archaeology of laboratory experiments and early chemistry: Oxford to Jamestown and back” focuses on exploring the practice of alchemy through the lenses of the archaeological materials coming from early chemical laboratories and uses scientific archaeology as a means to inform historical research and questions. Veronesi received his BA in Archaeology from the Sapeinza Universita di Roma in 2013, and his MSc Technology and Analysis of Archaeological Materials from the Institute of Archaeology, University College London in 2014.

True Colors, or the Revelatory Nature of Cold

By Thijs Hagendijk

Heat is transformative, brings about change, separates substances or bring them together. Every student of chemistry knows how to enable or enhance a chemical reaction by applying energy to a system, usually in the form of heat. Early modern practitioners did not think otherwise. Fire was the transformative element and key to the production of all kinds of different materials, ranging from the philosopher’s stone to artisanal products such as glass, porcelain or pigments. Applying heat to bring about change is publicly ingrained thermodynamics, but one thing is even more obvious. Once heated, things have to cool down again.

Figure 1: Eikelenberg’s notes on the art of painting, comprising five different manuscripts. Photograph: Regionaal Archief Alkmaar.

When the request came to write a blogpost on cold and recipes, I was somewhat hesitant. Heat seems to elicit the most interesting stories and anecdotes, but interesting cases with respect to cold failed to come to mind immediately. Hence, I tried a different approach and looked at how cold featured in a collection of overtly practical notes on the preparation of paint materials collected by the Dutch polymath and painter Simon Eikelenberg (1663-1738). Intended for publication, he promised his readers an “accurate descriptions of the origin of making, preparation and general use of paint materials, oils, mix-fluids and varnishes.”[1]  It was within the confines of this manuscript that I began to discern two themes with respect to cold in practices of making.

Figure 2: Reconstruction of one of Eikelenberg’s varnish recipes. The varnish was prepared in a glazed pot, placed in a sand bath and heated on fire. Photograph: Thijs Hagendijk.

It is only when things have cooled down that the transformative work of heat can really be judged. Eikelenberg describes for instance how he experimented with minium, a red lead-based pigment, which he heated in a crucible and placed in a fire. “The more it glowed, the more the minium turned yellow near the sides of the crucible, the lowest parts alike; which, when it was cold, appeared to be nothing else but yellow massicot.” [2] Eikelenberg also describes the preparation of various varnishes. Here too, quality and properties of substances are explicitly observed after the varnishes have cooled down. “When the varnish was cold I found that it was rather thin and that it did not cover well.” [3]  Another varnish was prepared on a hot sand bath, after which Eikelenberg “filtered it through a cloth and let it cool: it appeared then as a thickish and yellowish varnish.” [4]  Pay attention to the word “then”: there is a clear order of things that speaks through Eikelenberg’s notes. Being cold is a condition that precedes testing and Eikelenberg makes that rather explicit.

Figure 3: It is hard to achieve a homogeneous mixture when preparing varnishes. A whitish sediment is developing in this varnish, which is in coherence with Eikelenberg’s notes. Photograph: Thijs Hagendijk.

Whereas heat is transformative, it is only in the absence of heat that things can be trusted to stay the same. Continuing with the varnishes, Eikelenberg was well aware that their preparation does not stop after the ingredients have been heated and combined. As long as it is still hot, the apparently homogeneous concoction can easily coagulate and fall apart. Eikelenberg wrote in his notes: “We can conclude that to prevent curdling it is necessary not to stop stirring before the mixture is cold.” [5] Indeed, each time he made varnishes, Eikelenberg made sure to keep stirring until everything was cooled down: “stirring steadily until all was cold” or “having stirred until it became cold”.[6]

Figure 4: Eikelenberg mentions that: “[w]e can conclude that to prevent curdling it is necessary not to stop stirring before the mixture is cold.” Passage marked in red. Photograph: Regionaal Archief Alkmaar.

For Eikelenberg, heat was both friend and foe and until his varnishes reached firm, cool ground, they required careful guidance and attention. Cooling down was thus as arduous a process as heating the mixture was in the first place. Yet, once cooled down, true colors are revealed – deprived from heat and stabilized by the cold.

[1] Simon Eikelenberg, “Aantekeningen betreffende schilderen,” MS 391, Collectie Aanwinsten, Regionaal Archief Alkmaar: fol. 1. “Naukeurige beschrijving van de oorsprong of making, bereiding en ’t algemeen gebruik der verfstoffen, olijen, mengvogten en vernissen.”
[2] Simon Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, Collectie Aanwinsten, Regionaal Archief Alkmaar, fol. 806. Original: “na mate dat het gloejend wierd, veranderde de menij die naast tegen de zijden van de kroes aan-zat en wierd geel, gelyk ook ’t onderdtste; ‘t welk doe ‘t kout was niet anders dan gele masticot geleek”.
[3] Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 827. Original: “Doe de vernis koud was bevond ik ze wat dun en datze niet genoeg dekte.” Translation from: A. van Schendel, “Simon Eikelenberg’s Experiments on the Preparation of Varnishes,” Studies in Conservation 3 (1958), 130.
[4] Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 802. Original: “Doe ‘t wel vermengt was, kleijnsde ik ‘t door een doek en liet het kout worden, wanneer ‘tzelve een dikagtige en geelagtige vernis vertoonde” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 128.
[5] Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 824. Original: “Hieruijt kan men afnemen dat om ’t schiften voor te komen, men niet moet op-houden met roeren voordat se kout is.” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 129.
[6] Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 827. Original: “gestadig omroerende totdat het gantschelijk koud was.” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 130. Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 832. Original: “tot koutwordens toe geroert te hebben”.


Alchemical Recipes in the AlchemEast Project

By Matteo Martelli

What makes a recipe alchemical? Its inclusion in an alchemical treatise, one might suggest. Indeed, naïve as it may sound, such a simple answer opens an interesting perspective from which to look at the ancient alchemical tradition.

The earliest alchemical writings produced in Graeco-Roman Egypt (1st-2nd c. AD) include recipes that describe a variety of techniques for dyeing and manipulating the natural world – a spectrum of practices that goes far beyond simple attempts to produce gold out of ‘vile’ metals. Some of these techniques, ancient authors claim, were inherited from the Egyptian or Babylonian tradition; others reached Byzantium or Baghdad, often through translations of Greek texts into Syriac and Arabic.

This long-lasting tradition is as fluid as the boundaries of ancient alchemy. By mapping the specific practices and recipes detailed in each alchemical work, it will be possible to investigate changing ideas of alchemy over time as well as how these ideas responded to specific technological settings. On top of that, it will also be possible to follow the trajectories of single recipes which moved across works written in different languages or pertaining to different disciplines, such as medicine or natural philosophy.

Cinnabar (from the Monte Amiata mine, Tuscany) and metallic mercury

But let’s take an example from a set of texts that are being investigated in the framework of the ERC project AlchemEast, acronym for “Alchemy in the Making From ancient Babylonia via Graeco-Roman Egypt into the Byzantine, Syriac and Arabic traditions (1500 BCE – 1000 AD)”. Ancient natural philosophers and physicians recorded specific techniques for extracting mercury from cinnabar, its natural ore.

In his book On stones, Theophrastus, successor of Aristotle as head of the Lyceum, explained that it is possible to produce mercury by grinding cinnabar with vinegar in a copper mortar with a copper pestle.[1] The same procedure is described by Pliny the Elder, in book 32 of his Natural History, where the medical uses of minerals – mercury included! – are illustrated (NH 32.123).

Modern chemists noticed that these accounts actually described a mechano-chemical reaction between copper and cinnabar, a mercury sulfide: copper would react with sulfur, thus liberating free metallic mercury (chemically speaking, a redox reaction).[2] With the assistance of Lucia Maini and Massimo Gandolfi, two chemists of the AlchemEast team, we did replicate the technique with some adjustments. Rather than using a copper mortar – which proved to be very difficult to find in the shops that supply chemical labs today! – we decided to use a ceramic mortar where to grind pure cinnabar, acetic acid and copper powder.

Pure cinnabar, acetic acid and copper powder in a ceramic mortar

After grinding the mixture for a while, we were actually able to produce a layer of blackish powder (a mixture of metacinnabar and copper sulfide) on which a few drops of ‘dirty’ mercury were moving.

Mercury “floating” on a blackish layer of residues

The same procedure is described in ancient alchemical texts as well. The Graeco-Egyptian alchemist Zosimus of Panopolis (3rd-4th century AD) credits legendary figures, such as Maria the Jewess or Chymes, the eponymous hero of alchemy (called chymeia in Antiquity), with the use of similar technique for grinding cinnabar with vinegar in a lead or tin mortar.[3] Different metals were therefore used. In the lab, we actually tried to use tin rather than copper powder, thus obtaining a shiny mercury-tin amalgam.

Mercury-tin amalgam

We may preliminarily observe how this extraction technique was a kind of transdisciplinary know-how, shared by experts in different fields. A certain degree of variation is detectable in alchemical texts, which mention various metals. Moreover, ancient alchemists believed that mercury could be extracted from any metallic (or even mineral) body:  did this idea in some way depend on the empirical evidence they tried to conceptualize when treating cinnabar with a variety of metals?

This kind of questions are at the basis of the AlchemEast project, which explores ancient recipes from a double angle: as textual units that travelled over time and space; as invaluable windows on a wide spectrum of real practices and techniques. Textual criticism, replications, and historical investigations are critical keys to unlock ancient alchemical sources, from Babylonian tablets to Greek, Syriac and Arabic manuscripts.  This post is only a first, tentative attempt to illustrate how we applied this method, a preliminary result of our investigation, which, needless to say, is still “in the making.” We plan to continue keeping you posted in the following months.

[1] David E. Eichholz, Theophrastus, De Lapidibus, edited with Introduction, Translation and Commentary (Oxford: Clarendon Press, 1965), 81.
[2] Lazlo Takacs, “Quicksilver from Cinnabar. The First Documented Mechanochemical Reaction?” JOM. Journal of the Minerals, Metals and Materials Society, 52 (2000): 12-13.
[3] Marcelin Berthelot and Charles-Émile Ruelle, Collection des anciens alchimistes grecs (Paris: G. Steinheil, 1887-1888), vol. 2, 172. Part of Zosimus’ writings is only preserved in Syriac translation, where one finds further interesting details: cinnabar must be ground in the sun; copper filings are added to cinnabar and vinegar before grinding. The Syriac books of Zosimus will be published within the AlchemEast project.