Strange glass: Vitrium Antimonii

Pure antimony
Pure antimony

During my research fellowship at the Max Planck Institute for the History of Science in Berlin I studied the overlap (or lack thereof) of knowledge about making coloured and stained glass in artisanal versus medical circles in the eighteenth century Netherlands. Although it turned out that much of this knowledge was so tacit that it was never put down in writing properly, I found one remarkable boundary object, or rather a boundary material or ingredient: antimonial glass, or vitrium antimonii. Antimony is a lustrous grey metalloid, that occurs in nature as the sulfide mineral stibnite or antimonite. Roasted in an iron pot, it turns into antimony. Known since ancient times, the name is derived from the Greek anti-mono, meaning ‘not alone,’ because it does not occur in its pure form in nature. Because of its natural occurrence, colour and melting point, antimony was often confused with stibnite or lead. To add to the confusion the Dutch/German word ‘Spiesglas’ sometimes seems to refer to crude antimony, and at other times to antimonial glass. Moreover, the processes for creating glass of antimony and subsequently a red pigment from that glass, as described in Basil Valentine’s 1604 Triumphal Chariot of Antimony, are anything but straightforward.
Supposed antimonial glass (unverified modern reproduction)

Antimony is toxic for humans, and in early modern medicine it was sometimes employed in antimony cups, about which I have written before. Yet antimony could be transformed into other forms, and was thus used in both early modern visual arts and medicine. Although the exact origins of the recipes are unclear, by the seventeenth century, antimonial glass was generally understood as a clear, yellow or red vitreous substance made from calcined (powdered and roasted) antimony. This ‘glass’ was subsequently powdered and both used as a pigment in glass paints and solved in wine as a very strong emetic, a purge. The transformation from a silvery (mercurial) substance into something yellow or red (sulfurous) played a central role in alchemy, and was even associated with the secret to the Philosopher’s Stone, which could either transform all metals into gold or contained the secret to the universal panacea. This characteristic of silvery antimony transforming into yellow or red antimonial glass partly explains the popularity of such a toxic material.

According to Leiden professor of medicine, chemistry and botany Herman Boerhaave (1668-1737), the symbol for antimony:Antimony symbol “Denotes a chaos, χάος, world, or one thing which includes all: this is the character of antimony; wherein is found gold [the circle symbol], with plenty of an arsenical corrosive [the cross at the top].”About antimonial glass he remarked “The glass of antimony is almost mortally emetic; and when infused in wine, that is not considerably acid, it renders the liquor vomitive, without any great loss of its substance.”[1] Antimonial glass remained a popular ingredient for purges well into the nineteenth century, as shows from various apothecary and medical handbooks, as well as a pigment. Only with the rise of synthetic pigments, bacteriology and antisepsis does it seem to have disappeared from art and medicine.
Sample of supposed ‘Vitrum antimonii,’ probably eighteenth century. Source: Pharmaziemuseum Brixen, Italy.

With this disappearance, precise knowledge about the highly toxic process of creating antimonial glass disappeared as well. Fortunately there are people like history of chemistry professor Lawrence Principe, who reproduced many alchemical experiments and processes, amongst others that of making antimonial glass.[2] Principe discovered that antimonial glass can only be produced from stibnite ore containing some quartz, not from pure antimony – the quartz is essential for the vitrification of antimony. Without the quartz, the process results in dull grey lumps. A sample of supposed antimonial glass, probably from the eighteenth century, shows that there were apothecaries in Boerhaave’s time who already failed to understand this. Similarly, many apothecaries and artisans will have failed to produce a red pigment from glass of antimony, as Principe shows that it was not the antimony, but the residue of iron instruments that gave a preparation of antimonial glass and vinegar its red colour. It is this kind of reconstructive research that is essential to truly understand the complexities of early modern artisanal and medical knowledge.

[1] Herman Boerhaave, Elements of Chemistry, vol. 1, 68, and vol. 3, 322-3.

[2] Principe, Lawrence M. The Secrets of Alchemy. Chicago: University of Chicago Press, 2012, 90, 142-3.

Do(n’t) try this at home: Simon Witgeest’s New Theatre of Arts

To improve Memory

Take the hearts out of seven living Swallows and five Turtledoves, take dry Mint, Pennyroyal, Verbena, Eyebright, prepared Coriander, and Sage, a drachm each, a drachm and a half of flowers of Rosemary, two drachms each of Sweet flag and Cinnamon, one and a half drachm of Cloves, eight grains each of Musk and Gallia Muscata, five drachms each of Anacardium Honey and Styrax Calamita: make cookies out of this with Fennel-water. Every night when you go to bed, you should stick one of these cookies in your right nostril, and close it off with a ball of cotton until you have read thirty Verses from Vergil; when you have done this for some days, you should wet a cookie with Rose-water and stick it into your left nostril, and all you have read, you will remember for sure. Meanwhile, one should stay clear of the games of Venus, drunkenness, and other irregularities. After the meal one should chew on some Coriander and swallow one of the cookies, or dissolve one in Lavender-water, and cover the head with it while sleeping.[1]

Frontispiece of the first edition of Witgeest's 'New Theatre of Arts', 1659.
Frontispiece of the first edition of Witgeest’s ‘New Theatre of Arts’, 1659.

In my search for recipes for coloured glass for the project I am currently working on, I delve into all kinds of sources: manuscripts, chemistry books, apothecary handbooks, company archives. Yet one of the most fascinating I have seen so far is a small book that first appeared in Leiden in 1659, entitled Het nieuwe Toneel der Konsten, or new theatre of arts. It is a book containing sections on magic tricks, recipes and instructions for painting, etching, and making glass, as well as home remedies and recipes for fireworks. The glass recipes in the New Theatre were of little use to me, as they were abbreviated translations from Antonio Neri’s well-known 1612 De Arte Vitraria, but the book is fascinating nonetheless, making you want to test some of the recipes yourself.

Willem Goeree, by D. van der Plaets/P. van Gunst, source:
Willem Goeree, by D. van der Plaets/P. van Gunst, source:

Simon Witgeest is most likely a pseudonym – Witgeest literally means ‘white spirit’ in Dutch, and it probably served to indicate to readers that the recipes were innocent, rather than black magic. It has been argued that Witgeest was a pseudonym of Willem Goeree (1635-1711), a Dutch book trader and publisher of Dutch books on art theory and practices.[2] However, the arguments for this are limited, and given the thorough character of Goeree’s other books, it seems unlikely that he would he would have invested time or effort in the rather frivolous Theatre of Arts, even under a pen-name.

Some of the recipes, like the one quoted above to improve memory, border on the impossible and seem outright ridiculous, whereas others, such as a recipe that advises to lather winter hands with palm oil or chicken fat daily are quite common sense. Some appeal to the imagination, and one would be tempted to try them if the ingredients and the possible results were not so dangerous; take for example a recipe that advises a mixture of vinegar, egg white and quicksilver to make ones hands ‘fire proof.’ Or what to think of a recipe ‘to write in human skin, which cannot be undone:’ tattoos made with a needle and gunpowder, minium, or smalt.

The author stated in the preface that the book was meant to ‘shorten wintery nights,’ although many of the activities described would only be feasible for those with a lot of time, space and money. Following the recipes copied from Neri’s book on making glass for example would require a glass oven that can be fired up to 1200 degrees Celsius. This was probably why in the many subsequent editions that appeared in Dutch and German throughout the seventeenth and eighteenth century, the title was changed to The improved and extended natural magic book, or the new theatre of arts, and the sections on glass, drawing and etching were ditched in favour of more magic tricks, practical jokes, riddles, and entertainment with mathematical and astronomical brainteasers, as well as small chemical and physics experiments. Although it is highly unlikely that Witgeest’s contemporaries actually tried the recipes for making coloured glass, the other recipes will certainly have shortened winter nights for many.

[1] Witgeest, Simon. Het Nieuw Toneel Der Konsten, Bestaande Uyt Sesderley Stukken : Het Eerste, Handelt van Alderley Aardige Speeltjes En Klugjes : Het Tweede, van de Verligt-Konst in ’T Verwen En Schilderen : Het Derde, van Het Etzen En Plaat-Snijden : Het Vierde, van de Glas-Konst : Het Vijfde, Heeft Eenige Aardige Remedien Tegen Alderley Ziekten : Het Zesde, Is van de Vuur-Werken. Leiden: A.W. Sijthoff, 1659, p. 252-3.

[2] Landwehr, John, ‘Simon Witgeest’s Natuurlyk Tover-boek et alia,’ in Volkskunde, 1967, vol. I, p. 70-71.

Gout? Kidney stones? Have a cup of tea!

Here I am, one month into a visiting fellowship at the Max Planck Institute for the History of Science in Berlin – a wonderful institution full of scholars from all around the world working on a wide variety of topics. As you can imagine, a lot of tea and coffee is consumed here to keep everyone going. With all those different backgrounds, that leads to heated discussions about where the best coffee in the neighbourhood is sold, and what the right way is to make tea. That, combined with a remark about tea not spoiling in green glass in a text I was researching, reminded me of Cornelis Bontekoe (1647 – 1685), alias the tea doctor, who was born in Alkmaar (the Netherlands) and died here in Berlin.

Cornelis Bontekoe. Copperplate by Adriaen Haelweg.
Cornelis Bontekoe.
Copperplate by Adriaen Haelweg.

Bontekoe was born Cornelis Dekker, but took the surname Bontekoe (literally ‘spotted cow’ in Dutch) after the spotted cow on the shield of his father’s grocery shop. After obtaining his M.D. at Leiden University in 1667, he established a practice as a physician in Alkmaar. Bontekoe strongly advocated the use of fashionable products such as tea, coffee, cacao and tobacco to improve one’s health, which led to suspicions that he had a deal with the Dutch East Indian Company, the big importer of these products at the time. Deal or not, Bontekoe, who was known in intellectual circles as a passionate Cartesian and who went on to have a career as a university professor and court physician in Hamburg, Frankfurt, and Berlin, would go down in history as ‘the tea doctor.’

This was mainly due to his Tractaat van het excellenste kruyd Thee, or tractate on the most excellent herbal tea, subtitle ‘which shows the right use, and the great powers of it in health, and sickness, printed in The Hague in 1678 and reprinted repeatedly. The first part of the tractate is rather curious, an anti-Aristotelian rant that criticizes the wide-spread beliefs that drinking water is bad for you, beer, wine, and butter milk preferable, and the apparent dominant ideal of beauty:

People hate and despise the small and delicate, the skinny and emaciated Bodies, which resemble a ghost or a skeleton rather than a man. People want to be fat, big, and coarse, stout and well-build, full of power and vigor; one should be able to hold down one’s liquor, that is health!

Title page to Cornelis Bontekoe's Tractate on Tea
Title page to Cornelis Bontekoe’s Tractate on Tea

In over 300 pages, Bontekoe refutes common misunderstandings about tea, such as that it would dry out the body, weaken the stomach, stimulate the production of bile, cause shaky limbs, epilepsy, and even infertility. He argues that although drinking cold water is unhealthy, boiled water with the added benefit of the ‘herb of tea’ has a beneficent effect on the mouth, digestive system, blood, and mind, hydrating the body without intoxicating it, stimulating digestion and reducing flatulence.

Tea according to Bontekoe stimulates the mind, improves ones mood, prevents kidney and bladder stones, can help cure gout and he common cold, and warms the blood, but mixed with milk and sugar tempers excessive heat in the body. My favourite argument however is that of the huge size and population of countries like China and Japan, where people drink tea all their lives.

Ladies drinking tea, Pieter van den Berge, ca. 1694 - 1737. The verse at the bottom of the page satirizes the fashion of drinking tea. Courtesy of the Rijksmuseum.
Ladies drinking tea, Pieter van den Berge, ca. 1694 – 1737. The verse at the bottom of the page satirizes the fashion of drinking tea. Courtesy of the Rijksmuseum.

The tractate closes with a chapter on what good tea is: as fresh and white as possible, not too bitter, made with fresh, clean rain water that has not been boiled too long, and it should be drunk from earthenware or tin cups instead of copper ones. Tea should be not too strong, and no sugar should be added. Although there is no limit to the amount that can be had, yet those who want to sleep well at night should not drink it after midday.

As for Boerhaave’s remark that tea spoils in clear glass but remains uncorrupted in green glass; this appears to have had something to do with the fact that “by using a great deal of salt to a small quantity of flints, the glass becomes very clear; but is weak and frail, apt to crack by fire and water, and by age grows dull; and even infects liquors put in it, and sometimes destroys them utterly.” Green glass was generally stronger than clear glass, although the green colour came from copper oxides – the one substance Bontekoe warned not to drink one’s tea from….

Cup of tea, anyone?


Bontekoe, Cornelis, Tractaat van het excellenste kruyd thee: ‘t Welk vertoond het regte gebruyk, en de grote kragten van ‘t selve in gesondheid, en siekten: benevens een kort discours op het leven, de siekte, en de dood: mitsgaders op de medicijne, en de medicijns van dese tijd, en speciaal van ons land. Ten dienste van die gene, die lust hebben, om langer, gesonder, en wijser te leven, als de meeste menschen nu in ‘t gemeen doen. (The Hague: Pieter Hagen, 1678).

Boerhaave, Herman. Elementa chemiae, quae anniversario labore docuit in publicis, privatisque scholis. vol. i (Leiden: Isaak Severinus, 1732).

A gemstone for every ailment?

Last week, I wrote about Boerhaave’s admiration for the stained glass windows in the St. John church in Gouda, and how his appreciation can be understood in the context of his life and times. Yet of course, the learned man did not write about stained glass windows in his chemistry book just because he thought they were beautiful. Always the scholar, Boerhaave had another reason to be interested in coloured glass, rooted in the medical and chemical theory of the day. In the Elements of Chemistry, Boerhaave described a number of ways to make coloured glass, but warns that this tends to result in artificial gems that, however lustrous, are more brittle than the real thing.[1]

Brooch, 1740-1750, Silver set with pastes (glass). Courtesy of the V&A (object nr. M.198-2007)
Brooch, 1740-1750, Silver set with pastes (glass). Courtesy of the V&A (object nr. M.198-2007)

Fake gemstones were used frequently in jewellery and fashion in the eighteenth century, but Boerhaave’s interest in them may still seem a bit curious. However, it is quite understandable in the light of a 1672 treatise by Robert Boyle, one of the alchemists Boerhaave admired. Boyle’s An essay, about the origine and virtue of gems argues that gem stones are infused with mineral and metal juices or particles when they are formed in the earth, either through great pressure, cold, or heat.[2]

These minerals and metals have medicinal qualities, and by grinding gemstones to powder, the medicinal qualities can be used in curative potions, creams, et cetera. But gemstones were rare, so it was beneficial for the early modern physician/chemist/natural philosopher to be able to create artificial gemstones with the same properties as real ones. As artificial gemstones are made mimicking the natural process, by infusing crystal with metals, it made perfect sense for Boyle, Boerhaave, and their contemporaries to use both natural and artificial gemstones as materia medica, basic medical materials.

Title page of Robert Boyle's 1673 'An essay, about the origine and virtue of gems.'
Title page of Robert Boyle’s 1672 ‘An essay, about the origine and virtue of gems.’

Artificial gemstones are an interesting case, as they shows that in the early modern period, the same artisanal and chemical knowledge and practices were relevant for experts in a number of fields, such as glassmaking, jewellery making, chemistry, pharmacy, and medicine. Often, these fields overlapped in more than one respect of course, and as I mentioned last week, studying the use of materials in the early modern period is a route into understanding the work of hybrid experts, people who combined artisanal and scholarly theories and practices.[3]

In the future, I hope to make the creation and use of gemstones in eighteenth-century chemistry and medicine one of the case studies in my research project. These initial findings raise questions about how involved university-trained chemists actually were in the making of materials such as artificial gemstones. Did they make them themselves in their laboratories? Or did they obtain them from glassmakers or apothecaries? And exactly how were the gemstones used in medicine and pharmacy? What were the various theories about their curative properties, and how were they transferred to the patient? Was the alchemical understanding of gemstones significantly different from the chemical understanding, or were alchemical theories and practices transferred into the chemistry and medicine of the late eighteenth century?

But first, summer, and on my program are a research trip to London, to look into a massive manuscript containing lecture notes taken by a student of the Leiden chemistry professor Hieronymus Gaub (1705-1780), presenting a paper at the huge and hugely exciting ICHSTM conference in Manchester, and delving into the work of Abraham Kaau Boerhaave (1715-1758), Boerhaave’s deaf nephew. I aim to keep the Medicine Chest filled with updates!

[1] Boerhaave, Herman. A new method of chemistry, 2 Vols, Vol. I, tranl. by Peter Shaw, London, 1741, p. 182-187.

[2] Boyle, Robert. An essay, about the origine and virtue of gems, London, 1673.

[3] Klein, Ursula, en Emma C. Spary. “Introduction: Why Materials?” In Materials and Expertise in Early Modern Europe. Between Market and Laboratory., Ursula Klein and Emma C. Spary (eds.), 1–23. Chicago and London: University of California Press, 2010, 1, 6.

Metals and chemical knowledge in unexpected places: stained glass windows

This week I am diverting a little from my usual focus – I just found this too fascinating not to share it. So far, I’ve mainly concentrated on the use of metals in medicine and chemistry. Yet of course, metals were used in numerous other ways in the eighteenth century. There are the obvious applications if making tools and instruments, for money, jewellery, locksmithing, and cutlery. Metals were also essential in other arts and crafts, such as the creation of (coloured) glass. This may seem utterly artisanal, but the skills and knowledge involved were indeed relevant for academic chemists as well, as shows form Herman Boerhaave’s 1732 chemistry handbook.

In a section of the use of chemistry for the arts and crafts, he devotes over six pages to making glass, and how to colour it. Partly this makes sense, as a chemist was (and is) dependent on glass objects such as phials and bottles.

Glass retorts used in the chemical laboratory, from Boerhaave, Elementa Chemiae.
Glass retorts used in the chemical laboratory, from Boerhaave, Elementa Chemiae.

For example, Boerhaave explains that experiments have been made to aggravate glass with lead, but that these have failed so far as the addition of the lead tends to make glass brittle, rendering it unusable. Yet why would an academic chemist be interested in applications such as the creation of coloured glass? Boerhaave writes admiringly about the ‘Gouda glasses,’ the stained glass windows in the St Jan church in Gouda:

“There is also a […] kind of painting, which represents things on glass the most beuatiful yet transparent colours: the wonders of this art we see in great perfection in the windows of a church at Guada in Holland; which no modern performance can come up to. By means of this art they lay colours on the surface of the glass, which being baked by force of fire, their former lustre improved, and their substance diffused to a perfect transparency, penetrates the body of the glass, yet without passing a hair’s breadth beyond their assigned limits, or blending with the adjacent ones. I scarce know of any thing more curious and beautiful, or that contributes more to the ornament of churches, halls, and other buildings. The recovery of this art, now almost lost, is hardly to be expected, except from some chemist who should apply the discoveries of his art to this use.”[1]

The birth of Jesus, window 12 in the St Jan church in Gouda, made in 1564.
The birth of Jesus, window 12 in the St Jan church in Gouda, made in 1564.

Subsequently, Boerhaave lists other uses of glass, and the various methods to make it, and how to colour it with different metals. His admiration of the Gouda windows is one of the few insights he gave into his personal preferences outside his professional life. To understand this rare expression of emotion on a subject so different from his usual discourse, it is important to keep two things in mind. First, as convincingly argued by Knoeff in her 2002 book on Boerhaave, the man was deeply devout. Although the church windows at Gouda also contained more worldly, politically inspired images, the biblical representations in the impressive windows must have moved a religious man in a predominantly Protestant country, in which religious pictures -unlike religious symbols- in the public domain were quite rare.

Secondly, the Gouda church windows were and are among the great monuments in the Netherlands. For Boerhaave, who hardly travelled and whose farthest journey had been to Harderwijk, about one hundred kilometres from Leiden, these windows must have been one of the most beautiful monuments he saw in his life.

However, Boerhaave’s knowledge about and admiration for the craft of glass staining in general and for the Gouda windows in particular also confirms recent scholarship on the boundary nature of early modern chemical and technical knowledge and practices. Studying the use of materials in the early modern period is a route into understanding  mixed artisanal and learned practices, and reveals the existence of what Klein and Spary call ‘hybrid experts,’ men and women who combined artisanal and scholarly skills, terms, reasoning and explanations.[2] The hybrid expertise of people like Boerhaave and his contemporaries in turn can give us insights in issues such as discipline formation, and the epistemological and socio-economical developments preceding the industrial revolution.

        [1] Boerhaave, Herman. Elementa chemiae, quae anniversario labore docuit in publicis, privatisque scholis. 2 vols, vo.l. I, Leiden: Isaak Severinus, 1732, p. 180 cont.

[2] Klein, Ursula, en Emma C. Spary. “Introduction: Why Materials?” In Materials and Expertise in Early Modern Europe. Between Market and Laboratory., Ursula Klein and Emma C. Spary (eds.), 1–23. Chicago and London: University of California Press, 2010, 1, 6.