Category Archives: Experimentation

How to Sublime Mercury: Reading Like a Philosopher in Medieval Europe

This month, we’re excited to collaborate with History of Knowledge to celebrate the upcoming conference, Learning by the Book: Manuals and Handbooks in the History of Knowledge. The five-day event takes place at Princeton in June and features a “blogged conference” to complement traditional panel presentations. For the next few Thursdays, the Recipes Project will cross-post selections from the conference (with RP readers noting  the extended length, in keeping with HoK posts). These features are just a taste of more than thirty works produced for the conference, and readers are invited to read the full selection here. Enjoy!

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Jennifer M. Rampling

When it comes to “how-to” books, alchemy poses particular problems. Medieval alchemical treatises claimed to offer detailed advice on a host of spectacular products and processes, ranging from the Philosophers’ Stone, a transmuting agent capable of turning base metals into gold and silver, to medicinal elixirs that offered cures for otherwise intractable diseases, as well as the prospect of renewed youth and an extended life span. Yet, at least to modern eyes, no amount of “know-how” could teach anyone how to make these things — they are impossible practices, which no alchemist can ever have successfully carried out, nor described in accurate, replicable instructions. What, then, is the function of a “manual” of alchemy?

First, many of the early readers who studied alchemical writings did consider these ends to be obtainable, while recognizing that their sources might not always include complete or accurate information. Even seemingly straightforward processes can be difficult to reproduce in practice. For instance, the Liber de aluminibus et salibus (Book of Alums and Salts), a Latin treatise translated from an Arabic exemplar and pseudonymously attributed to the Persian polymath al-Rāzī, includes a simple procedure for subliming mercury with vitriol (a metal sulphate) and “common” or “general” salt.[1] According to the text, this mixture will sublime to the top of the vessel in the form of “white and shining” crystals, a description that sounds a lot like corrosive sublimate (mercuric chloride, in modern parlance).

As it happens, corrosive sublimate was a staple ingredient of fourteenth- and fifteenth-century alchemy, although its manufacture normally requires a nitrous salt, such as saltpeter, rather than common salt. Working with Professor Lawrence Principe at the Johns Hopkins University, I have attempted to solve this puzzle by following al-Rāzī’s laconic instructions in a modern laboratory setting.

Figure 1. Grinding quicksilver, vitriol, and salt with mortar and pestle. Copyright of the author.
Figure 1. Grinding quicksilver, vitriol, and salt with mortar and pestle. Copyright of the author.

The Liber directs us to take as much quicksilver as we want, then grind it with equal quantities of vitriol and salt until the quicksilver “dies” in them — that is, until globules of mercury are no longer visible in the mixture. But does “quantity” refer to weight or volume? Although the recipe does not say, the answer must be weight, since measurement by volume results in an excess of quicksilver, which stubbornly refuses to die:

Figure 2. Excess quicksilver. Copyright of the author.
Figure 2. Excess quicksilver. Copyright of the author.

Once we have killed our quicksilver (the Liber tells us), we should leave the mixture in a bread oven overnight. In the morning, we moisten it with salt solution before returning it to the oven. We repeat the cycle of moistening and overnight heating until the mixture has tarnished to a reddish colour (an effect caused by the rusting of iron in the vitriol). Later recipes refine this process, suggesting different ways of achieving the same result. One Middle English procedure recommends grinding the mixture several times a day for two to three days, with “esy dryynge and moysty[n]g with a lytel vynegre.”[2] Another advises scooping the mixture onto an old potsherd and stirring it over hot embers until no moisture remains.[3] We left ours on a low heat overnight.

Figure 3. The mixture after being left overnight on a low heat. Copyright of the author.
Figure 3. The mixture after being left overnight on a low heat. Copyright of the author.

The mixture is now ready to be sublimed. According to pseudo-Rāzī, it should be placed in an aludel, sealed, and heated (a process that takes longer in winter than in summer). We must use a soft rather than a hasty fire. Otherwise, as one fifteenth-century writer warns, the quicksilver will lose its active power and sublime in its “crude” form — a hazard that can easily be replicated in a modern laboratory. If performed correctly, the mixture sublimes into a substance as “white as milk.”[4]

Figure 4. Sublimation in a glass aludel over gentle heat. Copyright of the author.
Figure 4. Sublimation in a glass aludel over gentle heat. Copyright of the author.

This is the point when our reconstruction foundered. As already noted, corrosive sublimate requires a nitrous salt — common salt, as specified in both the Liber and the Middle English variants, should not work. In fact, our practice based on common salt conspicuously failed to generate any white crystals.

On the other hand, replacing the NaCl with sal niter immediately produced the desired effect:

Figure 5. Lawrence Principe removes corrosive sublimate from the aludel head. Copyright of the author.
Figure 5. Lawrence Principe removes corrosive sublimate from the aludel head. Copyright of the author.

 

Figure 6. White crystals of corrosive sublimate. Copyright of the author.
Figure 6. White crystals of corrosive sublimate. Copyright of the author.

Our initial failure illustrates the difficulty of precisely identifying ingredients from alchemical texts. Making corrosive sublimate seems to rely on an ability to distinguish between the properties of different salts, but can we acquire that knowledge entirely from books? Perhaps lack of technical expertise explains the “transmutation” of sal niter into common salt as a transcription error made by a scribe unversed in chemical procedures. Alternatively, our saline setbacks may result from our own lack of experience with this type of procedure.

We are certainly not the first experimenters to face this dilemma. Medieval and early modern recipe collections contain hundreds of procedures for subliming mercury, involving diverse salts and methods of preparation, and no doubt resulting in a variety of chemical products (even pseudo-Rāzī follows up his common salt recipe with a variant using sal ammoniac [5]). But readers also knew that not all recipes were reliable. As the English alchemist Thomas Norton warned the readers of his Ordinal of Alchemy (1477):

Avoide youre bokis writen of receytis,

For al such receptis be ful of deceytis.[6]

Norton was suspicious of recipes precisely because they offered fixed, literal readings of ingredients — but such readings could be wrong. The writers of alchemical treatises typically chose to present themselves as philosophers rather than artisans, whose knowledge stemmed from a profound understanding of nature gleaned not only from practice, but also from studying the writings of past authorities. These “philosophers” emphasized the privileged nature of alchemical knowledge and the need to preserve its secrets from impious or otherwise undeserving readers: an injunction manifested in their use of cover names, allegories, and other methods of obfuscation. In the hands of a self-identified alchemical philosopher, a term like “mercury” could take on almost as many identities as there are chemical substances.

This strategy placed a burden on readers, who sought to disentangle practical instruction from a web of possible meanings. Take, for instance, the opening procedure in one of the most influential works of Latin alchemy: the Testamentum. This lengthy treatise, probably written in the 1330s by a follower of the Catalan philosopher Ramon Llull (ca. 1232–ca. 1315), uses Lullian style diagrams to express alchemical doctrines and practices.[7] Here the writer plots his ingredients onto an alphabetical wheel:

Figure 7. Pseudo-Lullian wheel from the Practica Testamenti. New Haven, Yale University, Beinecke Rare Books & Manuscripts Library, MS Mellon 12 (mid. 15th cent.), fol. 97v. Courtesy of the Beinecke Library.
Figure 7. Pseudo-Lullian wheel from the Practica Testamenti. New Haven, Yale University, Beinecke Rare Books & Manuscripts Library, MS Mellon 12 (mid. 15th cent.), fol. 97v. Courtesy of the Beinecke Library.

The wheel begins with “A” (Deus), signifying God. The practice starts with B (defined in both text and diagram as quicksilver), C (saltpeter), and D (vitriol azoqueus), a combination that strongly hints at the making of corrosive sublimate. Has the author of the text simply decked a simple procedure in the garb of Lullian philosophy? Or are the terms merely cover names for other substances, as suggested by the fact that vitriol is qualified as “azoqueus”?

A naive reader may have tried to follow the instructions as they stand. A reader more familiar with the conventions of alchemical writing might regard several of the terms with suspicion. Is ordinary mercury intended, for instance, or does B denote some other “mercury”? And if a procedure fails to work, who is to blame — the authority for setting down a faulty procedure or the reader for supplying a faulty interpretation? Under such circumstances, what the novice alchemist really needs is not a manual of chemical practice, but advice on how to read such practices in a philosophical way. It is in this regard that works like the Testamentum truly come into their own.

 

I am grateful to Professor Lawrence Principe (Johns Hopkins University) and to the David A. Gardner ’69 Magic Project (Princeton University) for supporting the experimental reconstructions detailed above.

[1] Ps. Razi, Liber de aluminibus et salibus, in Robert Steele, “Practical Chemistry in the Twelfth Century. Rasis de aluminibus et salibus,” Isis 12, 1 (1929): 10-46, on p. 24; see also Julius Ruska, Das Buch der Alaune und Salze. Ein Grundwerk der spätlateinisches Alchimie (Berlin: Verlag Chemie, 1935). The Arabic version of the text is currently being edited by Gabriele Ferrario.

[2] Oxford, Bodleian Library, MS Ashmole 1451, fol. 5v.

[3] Oxford, Bodleian Library, MS Ashmole 759, fol. 42r.

[4] MS Ashmole 759, fol. 42v.

[5] Steele, “Practical Chemistry,” 24.

[6] Thomas Norton’s Ordinal of Alchemy, ed. John Reidy (London: Published for the Early English Text Society by the Oxford University Press, 1975), 7.

[7] On the Testamentum and its author, see Michela Pereira and Barbara Spaggiari, Il Testamentum alchemico attribuito a Raimondo Lullo: Edizione del testo latino e catalano dal manoscritto Oxford, Corpus Christi College, 255 (Florence: SISMEL, 1999).

 

Blog Series: Learning by the Book

Join the conversation on Twitter with the hashtag #lbtb18. Tweet or email links to related discussions. Read more posts in this series, and check out the conference website.

Vicissitudes in Soldering. Reading and Working with a Historical Gold- and Silversmithing Manual

This month, we’re excited to collaborate with History of Knowledge to celebrate the upcoming conference, Learning by the Book: Manuals and Handbooks in the History of Knowledge. The five-day event takes place at Princeton in June and features a “blogged conference” to complement traditional panel presentations. For the next few Thursdays, the Recipes Project will cross-post selections from the conference (with RP readers noting  the extended length, in keeping with HoK posts). These features are just a taste of more than thirty works produced for the conference, and readers are invited to read the full selection here. Enjoy!

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Thijs Hagendijk and Tonny Beentjes

In 1721, the Dutch craftsman Willem van Laer (1674-1722) published a Guidebook for Upcoming Gold- and Silversmiths. Intended as a manual to educate young novices, the Guidebook discussed a variety of different practices, techniques, and skills that ranged from assays to determine the quality of precious metals to sand mold casting and polishing (Figure 1). Four different editions, including one pirated copy, appeared in less than fifty years, attesting to its popularity. The book was explicitly aimed at teaching young readers how to do and make things. Van Laer reassured readers by saying “there will be few young gold- or silversmiths, who won’t find anything to their liking and benefit while reading this book; they will be led by hand to the knowledge of many things.”[1] Yet, however confident Van Laer might come across in this passage, there is sufficient reason to question the actual success of Guidebook at explaining and delivering these skills. Practical knowledge is often better demonstrated than written down. Van Laer was very well aware of this fact and offered disclaimers warning his readers that full comprehension of the text was only achieved when complemented with manual instruction. This begs the question of what could, in fact, be learned from the Guidebook.

Figure 1. Title page of the Guidebook. Copy held by the Rijksmuseum Research Library, Amsterdam. (Call number: 305 E 33). Photo by Thijs Hagendijk.
Figure 1. Title page of the Guidebook. Copy held by the Rijksmuseum Research Library, Amsterdam. (Call number: 305 E 33). Photo by Thijs Hagendijk.

The best way to answer this question is to look at historical evidence, primarily in the form of marginalia or other signs of usage, that indicates how the Guidebook was read and used on the shop floor. Unfortunately, not much of this evidence has survived for reasons that historians Natasha Glaisyer and Sara Pennell have observed in their study of early modern didactic literature. They note an irony in the fact that books that were most read and used did not make it to our libraries.[2] Indeed, most Guidebooks that reside in Dutch libraries are neat and almost spotless copies – we even found a copy with its pages still uncut! (We ended up cutting its pages almost three hundred years after publication, but that is another story). This virtual lack of historical evidence pushed us in a different direction. We decided to approach the Guidebook experimentally by performing historical re-enactments. By reading and working with the text as if we were learning how to make and do things, we were able to get a better grasp of Van Laer’s potential audience and the role the book might have played in historical learning practices and the acquisition of practical skills. The re-enactments gave rise to various insights.[3] In this post, we discuss one specific result, which is a story involving both success and failure.

Part of Van Laer’s discussion of soldering features the introduction of a “convenient soldering lamp.” Even though the better part of soldering usually happened in the forge, Van Laer presents his soldering lamp so that “the maker won’t need to put the entire piece back into the fire for a tiny leak or mistake only.”[4] For a silversmith, putting a soldered piece back into the fire was always risky as the soldered joints could melt again and cause more trouble than initially was the case. The preferable method was to repair a soldered piece without having to expose it again to relatively high temperatures, which is where the soldering lamp comes in. Basically, the soldering lamp resembles a modified oil lamp with an extended snout. To reach temperatures high enough to melt the solder, one had to use a small blowpipe to blow additional air through the flame. Skillful blowing would subsequently result in a second tiny yet feisty blue flame hot enough to locally melt silver. That is, at least, what Van Laer seemed to suggest: “when the tip of the flame of such burning Lamp is blown against the spot that needs to be soldered, it makes it hotter over there and the solder will easily run.”[5]

Figure 2. Engraving of gold- and silversmithing tools. Numbers 7 and 8 indicate the soldering lamp, number 9 the blowpipe. Copy of the Guidebook held by the Rijksmuseum Library, Amsterdam (Call number: 305 E 33). Photo by Thijs Hagendijk.
Figure 2. Engraving of gold- and silversmithing tools. Numbers 7 and 8 indicate the soldering lamp, number 9 the blowpipe. Copy of the Guidebook held by the Rijksmuseum Library, Amsterdam (Call number: 305 E 33). Photo by Thijs Hagendijk.

To find out whether we could indeed solder this way, we decided to build a soldering lamp following Van Laer’s instructions. Luckily, Van Laer was meticulously detailed with respect to the lamp, discussing its dimensions and the materials needed to produce it. According to him, the lamp should be made from brass and should measure 3 inches across and 1 inch in height. Additionally, there should be a wooden handle at its back and at the front a snout of about 5 or 6 inches long. To make sure he was well understood, Van Laer also included a schematic engraving of the lamp (Figure 2). We had more than enough information to work with, and based on his drawings and instructions we produced a much-desired replica of the lamp (Figure 3). We also laid our hands on a few historical blowpipes. Now that we had the materials, we could learn to handle the tool.

Figure 2 (Detail). Engraving of gold- and silversmithing tools. Numbers 7 and 8 indicate the soldering lamp, number 9 the blowpipe. Copy of the Guidebook held by the Rijksmuseum Library, Amsterdam (Call number: 305 E 33). Photo by Thijs Hagendijk.
Figure 2 (Detail). Engraving of gold- and silversmithing tools. Numbers 7 and 8 indicate the soldering lamp, number 9 the blowpipe. Copy of the Guidebook held by the Rijksmuseum Library, Amsterdam (Call number: 305 E 33). Photo by Thijs Hagendijk.

 

Figure 3. Replica of the soldering lamp. Photo by Thijs Hagendijk.
Figure 3. Replica of the soldering lamp. Photo by Thijs Hagendijk.

 

We filled the lamp’s reservoir with olive oil and stuffed its snout with a cotton lump. When we finally lit the lamp, the burning oil filled the room with a scent of grilled food. As an initial exercise, we took a small brass strip and tried to heat it until it started to glow. Here is how it went down, as recorded by Thijs in our fieldnotes:

Glowing the metal strip did not happen before we learned our first big lesson. Intuitively, Tonny and I started out by blowing hard through the blowpipe. The more air, the hotter the flame we thought. After trying for quite some time, it seemed as if we weren’t making any progress. We could steer the yellow flame, but were not able to get the blue flame where we wanted it. Yet, after I tried some more, it suddenly appeared that I had been blowing way too hard. By blowing rather softly on to the flame, suddenly the little blue flame emerged. In general, the blowing required much exercise. When later that afternoon a visitor dropped by for an interview, we saw the amount of skill that we already acquired. She too tried to produce a feisty blue flame by blowing through the flame, but did not succeed. To my own surprise, I was immediately able to point out what went wrong. The tip of the blowpipe should almost touch the pit of the flame, while one should blow out of the flame, both from beneath and from the inside-out. Cheeks filled with air, meanwhile breathing in, breathing out, breathing in, breathing out, filling the cheeks again and keep blowing at the same time. A rhythm occurs in blowing and breathing, which maybe most resembles what happens to your breathing when running.(Fieldnotes Thijs, April 4th, 2017).

Until this point, then, the story was quite successful. We were able to reverse-engineer the soldering lamp, and, like Van Laer explained, we could reproduce the feisty blue flame. Moreover, the blue flame proved rather hot indeed, as indicated by the different oxidation colors on the brass strip. However, as soon as we tried taking it to the next level, we ran into trouble.

Still happy with the progress we made, we now wanted to solder a very basic joint. We took another brass strip, hammered it round, and set out to solder its ends together to make a tiny cylinder. We fixed the cylinder in a standing pair of tweezers to free both our hands so we could steer the soldering lamp and hold the blowpipe. A little piece of solder was put on top of the joint, as well as little bit of borax, which is a flux used to facilitate the flow of melted solder. We lit the lamp and started blowing (Figure 4).

Figure 4. Soldering a brass ring. Note the tiny blue flame. Photo by Thijs Hagendijk.
Figure 4. Soldering a brass ring. Note the tiny blue flame. Photo by Thijs Hagendijk.

One hour later we were so out of breath that we stopped, but the cylinder had not yet been soldered. We failed. Even though we raised the temperature high enough to make the solder curl up like a drop, we never reached the final state in which it flows out and runs into the joint. Using the soldering lamp appeared less straightforward than we thought it would be.

We were curious to know what went wrong, but after several more days of trial-and-error, the list of questions and issues had only grown. We turned to the Guidebook and read and re-read the passages, only to discover that Van Laer was actually quite silent on the matter. Indeed, he carefully described how to assemble the soldering lamp, but spent hardly any time on how to handle it in practice. Should the object be pre-heated, or could the soldering lamp be used on cold objects, too? We blew and soldered against a piece of charcoal to create a reverberating heat source, but was this also how Van Laer meant to use the soldering lamp? Moreover, what type of solder should we use? Van Laer listed three distinct recipes for solder with different melting points, but did not indicate which one to use in combination with the soldering lamp. To date, we still have not been able to solder a proper joint using the lamp.

Interestingly, if we compare the above experiences with other re-enactments we performed, a general pattern starts to emerge.[6] For example, with respect to sand mold casting, Van Laer vividly described how to prepare and process the sand, but left his readers hanging when it came time to assemble a mold from it. Moreover, in his discussion of chasing, he meticulously described how to transfer a design to silver, but gave no guidance on how to perform the actual chasing process. Why would Van Laer alternate between exacting detail and virtual silence? What does this say about the usability of the book? And what could, in fact, be learned from this text?

The soldering story followed a similar pattern. While Van Laer carefully discussed each and every condition needed to succeed – the soldering lamp, recipes to prepare multiple types of solder, different sorts of fluxes – we failed once we arrived at the procedure itself. Is this due to our lack of skill in operating the blowpipe and soldering lamp, or are there aspects of eighteenth-century soldering that we no longer understand? In any case, the Guidebook’s guiding principle seems to be that core operations are best demonstrated rather than put into words. Van Laer did in fact confirm this with respect to the casting procedure. Just as he came to the very heart of the procedure, he abandoned his detailed exposition, stating that “the molding and casting cannot be learned as well as through manual education.”[7]

During our re-enactments, we therefore came to interpret the Guidebook as a text containing advanced practical knowledge, including tips, tricks, and best practices. Learning new skills from scratch, such as soldering, casting, or chasing, is still best done through manual education, but once mastered, the Guidebook can indicate new routes, spell out different paths, and show new variations on a theme.

 

[1] Willem van Laer, Weg-wyzer Voor Aankoomende Goud en Zilversmeden: Verhandelende veele wetenschappen, die Konsten raakende, zeer nut voor alle Jonge Goud en Zilversmeeden (Amsterdam: Fredrik Helm, 1721).

[2] Natasha Glaisyer and Sara Pennell, “Introduction,” in Didactic Literature in England 1500-1800, edited by Natasha Glaisyer, Sara Pennell (London: Ashgate, 2003), 7.

[3] For a more elaborate and contextualized overview of the re-enactments performed on the Guidebook, see Thijs Hagendijk, “Learning a Craft from Books. Historical Re-enactment of Functional Reading in Gold- and Silversmithing,” Nuncius 33, no. 2 (forthcoming Summer 2018).

[4] van Laer, Weg-wyzer, 125.

[5] Ibid, 126.

[6] Hagendijk, “Learning a Craft from Books.”

[7] van Laer, Weg-wyzer, 134.

Blog Series: Learning by the Book

Join the conversation on Twitter with the hashtag #lbtb18. Tweet or email links to related discussions. Read more posts in this series, and check out the conference website.

Gershom Bulkeley (1635-1713): A Sensory Chymist in Colonial Connecticut

By Donna Bilak

Who was Gershom Bulkeley? (you may well ask). A Harvard-educated Puritan gentleman from an important New England family, Bulkeley spent most of his life in Connecticut as a colonial divine, physician, and magistrate of upstanding (and by contemporary accounts obstinate) character. Bulkeley was also an iatrochymist – an aspect of his work that is only now starting to receive scholarly attention – and prolific compiler of notes about the medico-alchemical experiments that he conducted in his laboratory, likely a part of his dwelling place.

About 25 miles from where Bulkeley once lived, there now exists a kind of biblio-bunker in the University of Connecticut Health Center. This is where the Hartford Medical Historical Society Library keeps its collection of rare books and manuscripts. And this is where twenty-four manuscripts that are either by or associated with Bulkeley ended up. NB: there is treasure buried in this underground archive! (I am sure that as a Puritan with millenarian expectations, Gershom himself would be comforted to know that in the event of some kind of apocalyptic event, his notebooks will survive intact.)

I came across this cache back in 2011 while chasing down different leads for my dissertation about one of Bulkeley’s contemporaries, another Harvard-trained Puritan minister-physician-alchemist named John Allin (1623-1683). But in going through the various manuscripts, I was drawn to one of Bulkeley’s notebooks in particular: Bulkeley MS 5.

FIG 01 shows the spine of the 19th-century book cover (constructed of boards covered with period cloth of a by now indeterminate greenish-blue color), the spine bears the imprint “Parley’s Fables 1834” in faded gold letting.
(author’s own photograph)
FIG 02 the eighth page of the first (8-page) set of lab notes at the start of the book; on the right hand side is the start of the Institutiones medicae (shows for comparison of scrawly lab hand, and nice neat and TINY copy hand)
(author’s own photograph)

This is a small book that has been rebound using the cover from a 19th-century book of fairy tales, and it contains a series of entries about alchemical experiments that Bulkeley undertook between 1703 and 1706 scrawled across eight pages, with an additional sixty-three pages oriented upside down at the back of the book of more extensive laboratory notes of ongoing experiments, dated 1702 to 1707. At some point in time, both sets of notes were bound together with Bulkeley’s (undated) abridged copy of the Institutiones medicae by Lazare Rivière (1589-1655) – i.e., two hundred and forty-four densely written pages of Latin in a neat and minute hand ­– sandwiched between the aforementioned two sets of laboratory records. Intriguing stuff…

…because Bulkeley crammed this notebook full of particulars about chymical substances, instrumentation, and techniques. Bulkeley worked with different chymical substances for pharmaceutical production. His recorded experiments are filled with actions (tasting, weighing, drying, stirring, observing, waiting), and his laboratory entries document a range of output (he made salts, spirits, powders, pills, oils, dissolvents, elixirs). In their preparations, Bulkeley worked with iron, copper, and antimonial substances, as well as mercury, arsenic, silver, coral, and turpentine, and he used various chymical processes (calcination, coagulation, sublimation, evaporation, distillation). Bulkeley also detailed the equipment he used, describing things like various retorts (one is silver) and curcurbits (a glass one, a silver one), heavy and light scales, a blue jug, a copper vessel, an alembic, a receiver.

Another striking feature of this notebook is Bulkeley’s use of naked senses – taste, touch, and sight – as tools of investigation in his experiments. Bulkeley describes the consistency of experimental matter in comparison to common foodstuffs (“pudding” features large in his notes as a standard for assessing viscosity). Bulkeley also records the presence, or absence, of “lixiviate”, “vinegar”, “alcalisate”, or “urinous” tastes; interestingly, these references to tasting generally occur (when they do) at the conclusion of a given entry. Bulkeley’s haptic perception in the lab comes across in three entries, which record experiments that took place between January 27 and February 1, 1702. Here, Bulkeley detailed a distillation process involving nitre, mineral iron, and oil of vitriol (the objective appeared to be the production of aqua fortis), whereby an outcome of these distillation experiments was to harvest the caput mortuum.

Bulkeley observed that the dregs from January 27th “looked pretty white,” while that from January 29th was reddish, and he concluded with the comment, “Both the Cap. mort came out easily enough & crumbly but the 2d was not so soft & easy as the first/”. This seems to indicate mixed results in Bulkeley’s estimation. A third (and likely final) entry dated February 1 indicates the continuation of this experiment, with some changes in ingredients (i.e., the addition of flowers of sulphur) and procedure (Bulkeley undertook the sublimation of the matter in question). Notably, Bulkeley recorded that he did not lute his receiver (meaning that he did not undertake the preventative measure of smearing a claylike compound around this vessel to seal and thusly protect it in heating procedures).

This time, things did not go so well with the experiment:

I could not get no more off the broken pot: & flowers in the head that I could save, [6…] : that is in all. But it was the same pitcher in which I had destilled A. F. put in before, suc. Janr 27. & 29. & now it was cracked & had leaked a little out into the sand, had drunke up some into it; & I could not get the Cap. mort cleane off, nor the flowers absolutely cleane: & tis very Pbable some might evaporate, the Rec. not being luted on./ The sulphur in the Capt Mort was not fixt, but which upon a coale readily smoake & flame burne with a very fine blew flame./

FIG 03 LH page: Feb.1, 1702 caput mortuum experiment entry (goes with my transcription) (author’s own photograph)

These entries about the caput mortuum show Bulkeley’s bodily way of knowing as a form of assay, a testing procedure that links sensory analysis with chemical analysis in his evaluation of the progress of his work. This also shows that Bulkeley paid just as much attention to detailed sensory descriptions of his failures in the lab as he did to successes.

Bulkeley MS 5 is a valuable artifact of Bulkeley’s heuristic laboratory methods in the production of chemical pharmaceuticals, likely destined for use in his medical practice. While this notebook presents us with puzzles (what prompted its compilation? how was it used?), at the same time we are granted open access into Bulkeley’s experimental activities, a window into his dynamic medico-alchemical operations in a colonial community at the turn of the 18th century.

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Donna Bilak is a historian of early modern science specializing in material culture, and works on the history of alchemy in British North America, England and the Continent, the study of emblematics, and jewelry history and craft technology. Donna’s current research focuses on Atalanta fugiens (1618), a musical alchemical emblem book by the German physician and alchemist, Michael Maier; she is currently a Fellow at the Italian Academy for Advanced Studies in America (Columbia), working on her book about Atalanta fugiens and playful humanism; and Donna is co-editing a digital edition of this extraordinary work with Tara Nummedal supported by Brown University Library’s Mellon-funded Digital Publishing Initiative.

Indigo or no indigo?

Marieke Hendriksen

Fermenting indigo at Ock Pop Tock, Laos. January 2018.

When you say indigo, the first thing many people will think of is blue – jeans blue. (Or if you’re me, you’ll think first of a seventeenth-century recipe to make decorative blue prunes from wax with indigo. Occupational deformation.) But historically, indigo has been used in many more ways, and to make more dye colours than just blue, as I recently discovered. Today, most jeans are died using a synthetic blue dye, but indigo dyes, made from some of the over 750 species of the genus Indigofera as well as from some other plants, have been used to dye textiles for at least 6,000 years, while other subspecies of Indigofera were traditionally used as analgesics with anti-inflammatory properties.

The term ‘indigo’ according to the OED started to occur from the sixteenth century onwards in various European languages to denote blue dyes from India (or east Asia more generally), but can now also refer more generally to dyes, violet-blue light, or blue hues. It might be argued that the term only really applies to dyes created from Indigofera subspecies, while it could also be said that indigo is any dye created from plants through the decomposition of the glucoside indican, which exists not merely in the indigo-plant, but in woad and various other plants too.

Wash the freshly picked leaves…

While on holiday in Luang Prabang, Laos, I took a weaving and dying workshop with Ock Pop Tock, an organization that was established to preserve the traditional Laotian craft of making hand-loomed textiles. There, I discovered that there is more indigo besides Indigofera, and that one indigo plant can give many more dyes than just blue. They also have a wonderful informative website on natural dyes. At Ock Pop Tock, the plant species used to create indigo dyes is Persicaria tinctoria, or long leaf Japanese indigo, a plant indigenous not to Japan but to China, Vietnam, and Laos. Depending on how the leaves are treated, it can be used to create blue, green, black, and mauve.

…give them a good pounding to create a dye.

Using the fresh leaves creates a green dye, fermenting them for at least five days and adding limestone as a mordant gives a blue dye. Traditionally, the Lao believed that the dye was female, and that it fermented because it attracted a male spirit. To coax the spirit, the pots containing the dye would be dressed in a skirt, and a knife placed on top of the lid to ward off evil spirits that could ruin the dye. The fermentation is actually a naturally occurring oxidation process, with atmospheric oxygen as the oxidant. Regular stirring ensures the process continues. The longer the indigo mixture is left to ferment, the darker it turns. If this mixture is boiled, it turns black. Alternatively, a rare indigenous plant, mak bow or bow vine, can be added to the blue dye to create mauve.

The end result: a beautiful scarf

As part of the half-day workshop, I got to dye a silk scarf with a dye of my choice. I love green hues and wanted to make a dye from start to finish, so I chose to dye my scarf ‘indigo’ green. This was, apart from some pretty intense pounding of leaves, surprisingly easy. I got to pick fresh Persicaria tinctoria leaves in the beautiful garden, washed them, and mashed them vigorously in a mortar for about five minutes. Then I transferred the mashed leaves into a tub, added some cold water and then the raw silk scarf. After kneading the dye into the fabric for a couple of minutes, I could rinse my scarf and hang it to dry. The end result is a beautiful soft green scarf, that is not just a souvenir, but a tangible reminder of the traditional Laotian knowledge about natural dyes preserved and shared at Ock Pop Tock.