*This post was first published on the Recipes Project on 13 December 2018*

By Ruben Verwaal and Marieke Hendriksen

Ruben Verwaal is curator of the historical collections at Erasmus Medical Centre, Rotterdam, and at the Museum for Communication in The Hague. He obtained his PhD in June 2018 with a thesis on the role of bodily fluids in eighteenth-century chemistry. Marieke Hendriksen is a researcher on the Artechne Project and PI at the Art DATIS Project at Utrecht University and a long-time contributor to The Recipes Project. She specializes in the material culture of science and art in the long eighteenth century. Ruben and Marieke share an obsession with an eighteenth-century object that has since disappeared: a small chemical furnace. In a previous post, they wrote about reconstructing Boerhaave’s little furnace. Now they have two…

In August of this year, we wrote about our first attemptto recreate Boerhaave’s little furnace from old coal stoves. Meanwhile, Marieke’s dad, André, who is a skilled carpenter, was building a furnace from scratch, using Boerhaave’s description and a nineteenth-century example of a Boerhaave furnace in the collection of Museum Gouda as his guidelines. This resulted in a sturdy furnace of solid dried oak, much larger than the furnace we created from coal stoves.

The interesting thing about Boerhaave’s furnace is that many of the experiments that he described in his chemistry book, the Elementa Chemiae, for which the furnace can be used, required a very moderate degree of heat – one could say a cool rather than a hot oven. Two examples we mentioned previously were the distillation of rosemary, and the hatching of eggs, which Boerhaave said he believed his furnace could be used for too. The kind of egg is not specified, but for chicken eggs, the ideal temperature for hatching is 37,6 Celsius. Could we attain that temperature with our furnaces?

Boerhaave advised to use glowing coals or Dutch turf as fuel, with which a constant and moderate heat should be achieved that could be kept up to 24 hours. As turf is no longer won in the Netherlands, we started with some ordinary barbeque coals – and indeed managed to establish a fairly constant heat of around 30 Celsius in the large oven for an hour or so. But coals did not hatch any chicks.

Suspecting that turf may give better results, we set out to buy turf, which is still won in regions in Germany and Ireland. It turned out to be surprisingly difficult to buy in the Netherlands though. Eventually we managed to purchase a box of Irish turf through the American website of the online retailer we love to hate – but it took eight weeks (!) to arrive.  Though our cool oven still hasn’t incubated a chicken, the first results look promising.

Meanwhile, we started thinking about the experiments we’d like to recreate once we had all necessary materials. Since Ruben wrote his PhD thesis about bodily fluids, he is keen on reconstructing an experiment with milk from different mammals. Preferably, we’d compare the effects of prolonged mild heat on cow’s milk and human breast milk. Raw cow’s milk can be purchased at some farms, so Ruben cycled out to get some, while Marieke hesitantly contacted a friend who was pumping to feed her infant daughter to ask if she was willing to donate some of her leftovers to science. Note for future generations: Marieke has the coolest friends – she instantly said yes! For weeks, she gathered the left overs that her daughter did not drink in freezer bags.

Suddenly, it is December, and we have two furnaces, a box of Irish peat, and milk in two freezers. Now we ‘only’ have to make time for this reconstruction experiment… We live an hour apart and this is our pet project, so we’re desperately searching for a couple of days when we can take time of work. It turns out that the most difficult aspect of this reconstruction project is not the building of the furnaces or the sourcing of the necessary materials, but the absence of what Boerhaave obviously did have: cheap labour in the form of young assistants, who could take turns keeping the furnaces going day and night. We can only hope that once we do manage to take those days off, the Dutch winter is still as mild as it has been up till now!

This post first appeared on The Recipes Project on 23 August 2018.

By Ruben Verwaal and Marieke Hendriksen

Ruben Verwaal is curator of the historical collections at Erasmus Medical Centre, Rotterdam, and at the Museum for Communication in The Hague. He obtained his PhD in June 2018 with a thesis on the role of bodily fluids in eighteenth-century chemistry. Marieke Hendriksen is a postdoctoral researcher on the Artechne Project at Utrecht University and a long-time contributor to The Recipes Project. She specializes in the material culture of science and art in the long eighteenth century. Ruben and Marieke share an obsession with an eighteenth-century object that has since disappeared: a small chemical furnace.

With the introduction of chemistry into the university curriculum in the late seventeenth century, new practical needs arose for students  such as being able to perform experiments. Would it be possible to build a chemical furnace that provides a gentle heat, yields no smoke, and is safe for students to use? Herman Boerhaave (1668–1738) believed he found the perfect solution in, what came to be called, Boerhaave’s little furnace.

Boerhaave was professor of medicine, botany and chemistry at Leiden University in the early 18th century.[1] Instead of starting with the most difficult experiments with metals and minerals, he was convinced that students were better off when they learned the techniques of through simpler processes, such as distilling leaves and flowers, and fermenting bodily fluids. But most chemical laboratories were equipped with elaborate devices too complicated for freshmen students, who in the eighteenth century could be as young as fourteen. Moreover, the brick-build furnaces were designed to create high temperatures, in which small and delicate materials like rosemary leaves would burn instantly.[2] Boerhaave hence needed a device that was low-cost, user-friendly, and would provide a gentle heat.

A small wooden oven was the answer. Boerhaave claimed he had designed this type of furnace when he himself was studying chemistry in the 1690s. He opened the chapter on instruments in his chemistry textbook with the words: “I shall begin with my simplest furnace; which I invented forty years ago, when I practiced chemistry in no large study, where there was only one little chimney, and where I required several furnaces at once.”[3]

This kind of device was probably inspired by ordinary foot stoves. These little stoves, also known as foot warmers, were very popular in the Dutch Republic. Coming in a wide variety of shapes (square, octagonal, cylinder), these stoves often feature in books and paintings. Filled with glowing coals or peat, women placed the little stoves under their robes or blankets to keep warm.[4] Many foot stoves were equipped with a wire bail handle for lifting and easy transportation. Such stoves were used in carriages, sleighs, at home and in church to keep one’s feet warm. This ordinary foot warmer got new applications too, namely as tea and coffee stove,   and we suspect it was the model for the ‘simplest furnace’ in the Leiden chemical laboratory.

The gentle heat produced by Boerhaave’s small oven proved very useful in performing all kinds of chemical experiments. Take rosemary, for example, the evergreen aromatic shrub. Distilled atop a “violent fire”, it would have been turned to flame, smoke, and ashes. But when rosemary instead was distilled at “summer-heat” (approx. 85º F), the mild operation would instead reveal the most volatile, fragrant and aromatic part of the plant ordinarily exhaled in summer. The same process could be applied to Angelica, basil, and all other aromatic plants.

Boerhaave, in other words, attributed the success of his device to one’s control over gentle heat. Whenever the wooden oven was filled with hot pieces of coal or Dutch turf that was no longer smoking, it established a constant and moderate heat that could be kept up to 24 hours. As such, the instrument was perfect for students to perform all kinds of heating processes and distillations. In fact, he was so excited about this apparatus, that he claimed that “I believe eggs may be hatched by it”.[5]

Was Boerhaave’s little furnace really that user-friendly and effective as he claimed it was? We checked it out by recreating Boerhaave’s stove and performing experiments with it. Check out our next blog to entry to find out whether we succeeded!

References:

[1] More on Boerhaave, see Marieke Hendriksen, “Boerhaave’s Mineral Chemistry and Its Influence on Eighteenth-Century Pharmacy in the Netherlands and England”, Ambix(2018) and Ruben Verwaal, “The Nature of Blood: Debating Haematology and Blood Chemistry in the Eighteenth-Century Dutch Republic”, Early Science and Medicine(2017).

[2] Boerhaave, Elementa Chemiae (Leiden:  Isaac Severinus, 1732), vol 2, experiment 1.

[3] Ibid., vol 1.

[4] Le Francq van Berkhey,Natuurlyke historie van Holland (Amsterdam: Yntema and Tieboel, 1769–1778), vol. 3, 706-707, 1200.

[5] Boerhaave, Elementa Chemiae, vol 1.

This blog first appeared on The Recipes Project on 15 March 2018

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.

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.

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.

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 freshPersicaria 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.

Front page to a 1796 reprint of Dossie’s Handmaid

*This post first appeared on The Recipes Project Blog on 7 December 2017*

By Marieke Hendriksen

Robert Dossie (1717-1777) was and English apothecary, experimental chemist, and writer. Within just three years, he published three very successful handbooks: The elaboratory laid open (1758) on chemistry and pharmacy for ‘all practitioners of medicine’, Theory and practice of chirurgical pharmacy (1761) for surgeons, and The handmaid to the arts (1758), which taught ‘a perfect knowledge of the Materia Pictoriae’ such as painting, gilding, and japanning. Gibbs (1951, 1953) has written a short overview of Dossie’s life and work, with a focus on his role in the Society of the Arts, but paid no attention to the cohesion of his seemingly divergent work.

Lowengard (2006) has briefly noted that Dossie used a form typical for books about materia medica for his book on the arts, grouping the contents according to techniques employed as well as by the media to which they might be applied, yet his work has never been thoroughly analyzed. Did Dossie indeed transmit a way of structuring and presenting practical knowledge in text from one realm to another? Recipe collections and how-to books before the eighteenth century were often a mixture of medicinal and artisanal recipes and instructions, and the boundaries between medicine, chemistry, and the preparation and application of artist’s materials often so fluid as to be almost non-existent.

Moreover, some earlier printed books on painting and dying techniques did employ the format of a systematic discussion of materials and their preparations, followed by their application, for example Willem Goeree’s 1760 Verlichterie-kunde  What was novel about Dossie’s Handmaid of the Arts though was the combination of this way of presenting practical artisanal knowledge, his attempt to be encyclopaedic in his collection – listing the uses of the same base materials in the production of various artistic and decorative objects, and his very intentional use of the term ‘Materia Pictoriae’.

Rubia tinctorium (madder), one of the many plants that was both materia medica and materia pictoria

The latter appears to have been an attempt to subtly elevate the status of the visual and decorative arts by paralleling the materia pictoriae to the materia medica. Finally, the intended audience gives us more insight in how Dossie understood his own work. From the preface of the book, it appears that Dossie did not so much aim at the people creating visual and decorative objects, but at the professional preparers of artist’s materials, of whom he wrote: “a much greater share of knowledge in natural history, experimental philosophy, and chymistry, is required to the understanding the nature of the simples [sic], and principles of the composition, in a speculative light, than is consistent with the study of other subjects more immediately necessary to an artist.” (p. vii-viii)

In eighteenth-century England, high street chemists and druggists were evolving from preparers and sellers of chemical substances to compounders, stockists, and sellers of drugs and dispensers of medical advice, and it is in this light that Dossie’ work and his division between materia medica and materia pictorial must be seen. Did Dossie intentionally and successfully adapt and implement formats and language traditionally used in one field (medicine) for the organization and transmission of practical knowledge in text to others (chemistry and the arts)? To me it appears that in his mind, materia medica and materia pictoriae were both branches on the tree of chemistry, and that his corpus, which we now tend to see as divergent, was actually a cohesive body of work to him and his contemporaries.

Dupré, Sven, ed. Laboratories of Art : Alchemy and Art Technology from Antiquity to the 18th Century. Archimedes 37. Cham [u.a.]: Springer, 2014.

Gibbs, F.W. “Robert Dossie (1717–77) A Further Bibliographical Note.” Annals of Science 9, no. 2 (1953): 191–93.

Gibbs, F.W.  “Robert Dossie (1717–1777) and the Society of Arts.” Annals of Science 7, no. 2 (1951): 149–72.

Lowengard, Sarah. The Creation of Color in Eighteenth-Century Europe. Columbia University Press, 2006. http://www.gutenberg-e.org/lowengard/C_Chap05.html.

Worling, Peter M. ‘Pharmacy in the Early Modern World, 1617 to 1841 AD’, in Making Medicines: A Brief History of Pharmacy and Pharmaceuticals, ed. by Stuart Anderson (London: Pharmaceutical Press, 2005), pp. 57–76.

*This blog was originally published on The ARTECHNE Project Blog on 26 September 2017*

By Marieke Hendriksen

“Peintures en huile, en miniature et encaustique,” Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 8 (plates) (Paris, 1771). Plate I: Painting, Atelier, Paint Pallet and Brushes.

The terms ‘technique’ and ‘technical’ are used widely in relation to art, art history and science today, both to refer to the technical analysis of artworks and to a more holistic analysis of creative processes. Yet we do not have a history of the shifting meanings of the term ‘technique’ in the arts and sciences. The word ‘technique’ was a neologism in the vernacular, and started to appear in treatises on arts and sciences from the middle of the eighteenth century. Rooted in the Greek techne, which was translated routinely as ‘art’ until the mid-eighteenth century, technique referred to processes of making or doing and their products. Such processes had been described to previously as ‘art’, ‘methods’, ‘manners’ or ‘mechanics’ in the vernacular, and they were recorded in text with the intention of documenting and/or transmitting practical skills and knowledge.

On 26 and 27 October, Sven Dupré and I are hosting an international workshop at Utrecht University with the aim of bridging the gap between the changing concept of technique and the practices currently described by it. Questions we seek to answer are for example: how was what we now call ‘technique’ in the arts and sciences described and understood before the term took hold? More specifically, how were techniques in the arts described between 1500 and 1900? What kind of written sources can we distinguish, which terms were used to describe and instruct technique in various languages, and who were the intended audiences of these works?

Hans-Jörg Rheinberger will give a public keynote lecture, entitled “The Hands of the Engraver – Albert Flocon meets Gaston Bachelard”

Moreover, we will look at the linguistic history of technique in the arts, with questions such as why the term ‘technique’ first emerged around 1750, and what did it mean initially to artists, art theorists, and natural philosophers? Is there a connection with the emergence of categories such as aesthetics, fine art, craft, mechanics, and technology? Did the meaning of ‘technique’ and related concepts vary between periods, practices, and European languages, and how can we use data and concept mining to understand this? What do we mean by ‘technique’ in relation to art now, and can we use the same word to describe historical knowledge and practices?

Another issue closely related to the understanding of the concept of ‘technique’ in the arts is the development of so-called somatic language. Somatic language to describe measurements and sensory characteristics of materials traditionally played an important role in technical art texts, but seems to become rarer or more standardized over time. This kind of language guides the reader’s posture, as well as the use of their own body, and tools and materials, yet it is often unspecific and metaphorical (‘shift your weight’, ‘a handful’, ‘like yoghurt’), and meanings and interpretation can vary wildly in different languages, times, and cultures. How did the use of this kind of somatic language change in Europe between 1500 and 1950? What was the influence of standardization on conservation practices?

During the workshop, we will discuss these and related questions in panels of specialists from a variety of fields, such as history, art history, intellectual history, philosophy, and linguistics. Each interdisciplinary panel will focus on a particular concept, but there will also be ample time for exchange between the various panels.

Limited seating is available, please contact j.briggeman@uu.nl if you are interested in attending.