Category Archives: Marieke Hendriksen

The (lack of) power of gemstones

By Marieke Hendriksen

The idea of gemstones having curative powers has existed from ancient times until the present day. As I am interested in the use of chemical and mineral substances in eighteenth-century Dutch and particularly Boerhavian medicine, I am currently analysing medical and apothecary handbooks from this period and area to gain an idea of what eighteenth-century Dutch physicians and apothecaries thought of the alleged curative powers of gemstones. Unlike neighbouring countries, the Netherlands has no strong tradition of early modern lapidaries, so I was somewhat surprised to find regular mentions of gemstones in these sources anyway.

Front page of the 1741 Leiden edition of the Medicina Pharmaceutica
Front page of the 1741 Leiden edition of the Medicina Pharmaceutica

A number of examples can be found in a 1741 Dutch apothecary handbook about which I have written before here. It was re-edited by an apothecary, Schróder, and initiated by Boerhaave’s direct successor as professor of chemistry at Leiden University, Jerome Gaub: Medicina pharmaceutica, of Groote algemeene schatkamer der drôgbereidende geneeskonst, originally published by the Flemish apothecary and physician Robertus de Favarques. The new edition of this 1681 work appeared with the Leiden printer Severinus, and was received positively in the press. In De Favarques’/Schróder’s list of simples, an entire section is devoted to metals, minerals, and stones. Not only were the materials listed, but also an overview was given of where they were found and how they could be used in the apothecary shop. From these descriptions, it becomes clear that the powers of some metals and gemstones were still commonly accepted, whereas those of others seem to have fallen into disrepute.

Natural ultramarine pigment, made of powdered lapis lazily. Works a treat if you're feeling blue...
Natural ultramarine pigment, made of powdered lapis lazuli. Works a treat if you’re feeling blue…

Pulverised rock crystal for example is mentioned as a cure for diarrhoea, powdered lapis lazuli is prescribed to strengthen the heart and to alleviate melancholy. However, the authors are more sceptical about the uses of some other stones, especially when worn on the body. The eagle stone – not a true gemstone but some sort of hollow clay stone, is commonly believed to prevent miscarriage when worn around the neck, to ease labour when tied around the calf, and recommended by some in plasters to treat convulsions. However, the handbook warns, they are only good to stop bleeding and diarrhoea when taken in powdered form. Garnet and ruby, although commonly attributed with cordial powers, as well as with the power to ward off melancholy and venom, in this book too serve only in powdered form to curb sharpness in the body, to temper the flow of blood and faeces, and to dry. Similarly, it is said of sapphires that many powers are ascribed to them, which they do not possess, such as cordial, blood cleansing, and other powers. Basically, apart from lapis lazuli, all stones and gemstones in the list only qualify in powdered form as absorbents to stop bleeding and diarrhoea; no other applications are mentioned.

This focus on (gem)stones as only useful in medicine in powdered form to stop all kinds of bodily fluids from flowing freely suggests a strong humoural understanding of the medicinal powers of stones, the dry earthiness of which could temper the wetness of blood and phlegm. Moreover, the list shows a rejection of early modern understandings of (gem)stones as having curative powers from which one could benefit by wearing the stone on the body. Exactly why he seems to have thought lapis lazuli -the only source of expensive ultramarine pigment until the early nineteenth century- was an exception remains a mystery for now, but maybe I will be able to inform you about that in the near future…

Boerhaave’s contemporary fame: a letter from China to recipe books

By Marieke Hendriksen

Herman Boerhaave, J. Chapman, 1798. Source credit: http://ihm.nlm.nih.gov/images/B29694 via Wikimedia Commons.
Herman Boerhaave, J. Chapman, 1798. Source credit: http://ihm.nlm.nih.gov/images/B29694 via Wikimedia Commons.

My current research project focuses on how Herman Boerhaave’s (1668-1738) medical and chemical ideas, particularly those on metals, influenced the theories and practices of his students and other followers. The longer I work on this topic, the more I notice Boerhaave’s general influence on his contemporaries and the next generations. Already during his lifetime, Boerhaave was famous far beyond the borders of the Netherlands, even though he hardly left Leiden and the furthest journey he made during his life was to Harderwijk, a Dutch town about 100km from Leiden, where he gained his doctorate. A popular (alhough never documented) story told that a letter sent from China, addressed simply to ‘the illustrious prof. Boerhaave, physician in Europe,’ reached him without delay.

Then there was Boerhaave’s stove, a small wooden box-like incubator Boerhaave described in one of his text books and which students, apothecaries and amateurs constructed at least till the early nineteenth century to conduct chemical experiments, prepare ingredients for drugs, and even hatch eggs. Another trace of Boerhaave’s influence on Dutch eighteenth-century culture was the continuing description of dark candy sugar as ‘Boerhaave’s sugar,’ because he prescribed it as an ingredient in cough syrups. Yet most clearly of all can his influence be seen in both professional and private eighteenth-century manuscript recipe books.

Brown candy sugar, also known as 'Boerhaave's sugar' in the eighteenth century
Brown candy sugar, also known as ‘Boerhaave’s sugar’ in the eighteenth century. Image credit: © Alice Wiegand / CC-BY-SA-3.0 via Wikimedia Commons.

Although it may seem obvious that Boerhaave’s medicine influenced that of other medical men, it is interesting to see how diverse his influence was. Lately I compared a number of eighteenth-century Dutch manuscript recipe books and was pleasantly surprised by the different ways in which Boerhaave’s medicine influenced both medical men and others. In an anonymous recipe book that was probably compiled by a medical man of some sort, four recipes are attributed to Boerhaave, and three to his direct successor at Leiden University, Jerome Gaub (1705-1780). That this book was most likely used by a medical professional can be told from the fact that most of the recipes were written down in Latin, and measurements were given in apothecary shorthand, i.e. weights were indicated in drams.[1] Moreover, recipes for analgesics and purges to be used in persistent illnesses such as venereal disease and epilepsy, often accompanied by a note that they are only to be used if all else fails, are dominant, and ingredients like mercury, antimony, and sulphur are frequently listed.

This forms a stark contrast with household recipe books from the same period, like the anonymous ‘Medicamentboek’ that contains recipes attributed to ‘Bourhavi’ [sic] against fever and coughing. The most remarkable difference with the first recipe book is that almost all recipes are in Dutch, and contain primarily readily available ingredients, such as beer, bread, wine, honey, candy sugar, herbs, spices, rhubarb, tongue of veal, red cabbage, liquorice, and vinegar. Moreover, instead of cures for persistent and grave illnesses such as advanced venereal disease, this recipe book lists cures for more common ailments such as dandruff, irritated gums, coughing and winter hands.  Although some recipes in this book have been written in apothecary shorthand, in Latin, or contain more exotic ingredients such as red coral and boiled puppies, these entries are all in a different hand than the bulk of the recipes, suggesting the recipe collector occasionally asked a medical professional to add a recipe to his or her household medical recipes book.[2]

Rather than reading all these attributions to Boerhaave as direct evidence of medical networks, which is problematic, as they do not prove that the compiler had any affiliation with the names source, they can be read as proof of the diverse yet widely dispersed influence of Boerhaave’s medicine in eighteenth-century Dutch society.[3] For medical men, he was a professional example whose recipes, especially the more complicated ones that contained potentially dangerous ingredients such as metals, were collected as a resource for extreme cases. For laymen, Boerhaave’s name and simpler recipes, based on more readily available ingredients and aimed at more common ailments, carried equal authority.


[1] Anonymous. “Receptenboekje”, ca. 1750. Museum Boerhaave Library, Leiden: BOERH a 313.

[2] “Medicament boek : met een recept van Boerhaave tegen koorts”, 17XX. Museum Boerhaave Library, Leiden: BOERH a 308.

[3] For more on interpreting early modern recipe books, see Michelle DiMeo and Sara Pennell, eds. Reading and Writing Recipe Books 1550-1800. Manchester and New York: Manchester University Press, 2013.

A seventeenth-century miner’s brandy recipe

A mine, print from Goossen van Vreeswijck, Cabinet der Mineralen, Amsterdam 1675
A mine, print from Goossen van Vreeswijck, Cabinet der Mineralen, Amsterdam 1675

By Marieke Hendriksen

Recently, I’ve been studying, amongst others, the works of a seventeenth-century Dutch bergwerker, freely translated a miner, or rather a mining specialist. Goossen van Vreeswijck (ca. 1626- after 1689) was an adventurous man, who worked in the Low Countries, the German lands, Sweden, England, and even in regions presently in Surinam and Canada. He published a number of works on mining and alchemy in Dutch – a unique body of work that has been given little attention by historians of chemistry so far. Although Van Vreeswijck probably did not have a university education, he was well versed in the important alchemical and mining literature of his time, as he frequently discusses and criticizes authors such as Basil Valentine and Georg Agricola. His books are clearly aimed at other Dutchmen who will have to work in mines in faraway regions; they offer all kinds of practical and technical advice regarding the establishment and operation of a mine and the subtraction and chemistry of metals.

I am primarily interested in the use of metals in early modern chemistry and medicine, yet Van Vreeswijck’s work contains so many other gems that I could not withstand sharing one of them with you here. Probably because Van Vreeswijck’s audience was likely to spend long periods away from civilization, he also included recipes for the production of staples, such as brandy. In his book De Roode Leeuw, of het Sout der Philosophen (The Red Lion, or the Salt of the Philosophers, 1672), the title of which suggests a treatise on the matter of the Tincture or the Philosoher’s Stone, Van Vreeswijck discusses a wide variety of topics, ranging from the production of saltpetre from charcoal to the explanation of dreams and the best way to make brandy. Dutch brandy was usually made from grains like wheat or rye, but, Van Vreeswijck warned, this was not such a good idea as it might induce God’s wrath. He based this admonition on Isaiah 55:2, which says:

Wherefore do ye spend money for that which is not bread? and your labour for that which satisfieth not? hearken diligently unto me, and eat ye that which is good, and let your soul delight itself in fatness.

Exactly why it would be a better idea to make brandy from all other kinds of fruits and vegetables, as Van Vreeswijck continues to argue, does not become entirely clear – but he seems to imply he did not find these satisfying or good to eat (fattening) as such, and brandy was seen as a necessity with medicinal qualities. It was used, amongst others, as a diuretic and purgative.

Van Vreeswijck illustrated most of his work with images he had copied from the popular emblem books of Jacob Cats - who used this image of a hand picking up grapes as an emblem of virginity, rather than  to refer to brandy.
Van Vreeswijck illustrated most of his work with images he had copied from the popular emblem books of Jacob Cats – who used this image of a hand picking up grapes as an emblem of virginity, rather than to refer to brandy. Source: Jacob Cats, Maechden-plicht, Middelburg, 1618.

The list that follows, of what can be used as a basis for brandy, is impressive: anything from grapes, apples, pears, prunes, to raspberries and cherries, even cabbage will do. As grapes can be grown in most mild climates, instructions are given on how to set up and manage a vineyard. Another benefit of using grapes for brandy was the appearance of tartar and lees as by-products, which, Van Vreeswijck points out, are used in medicine, dying, and many other crafts. Yet if grapes were not available almost any other fruit would do. The fermentation process might need some encouragement, for which yeast, sourdough, tartar, alkaline salt, wine vinegar, saltpetre, or antimony could be used. Amounts are not mentioned, as they would have depended on the kind and amount of fruit used, nor are there any specific instructions for distillation. Goossen van Vreeswijck’s brandy ‘recipe’ should thus be seen in the context of his works – a set of practical pointers for miners and others who needed to produce things they otherwise would have bought. By including some Biblical references and illustrating his work with copies of emblems from the works of the hugely popular Dutch author Jacob Cats (1577-1660), he stressed his reliability.

Recipes for Glauber salt and the serendipity of research

Johan Rudolf Glauber (1604-1670)
Johan Rudolf Glauber (1604-1670)

By Marieke Hendriksen

The German apothecary and alchemist Johan Rudolf Glauber (1604-1670) spent much of his working life in Amsterdam. There, he used the facilities of a commercial glasshouse–“The Two Roses”–on the Rozengracht for some of his experiments.[1] By extracting the colours of metals by melting them into glass, Glauber hoped to come closer to the unveiling of the Philosopher’s Stone.[2] Although he never achieved this, his experiments proved highly relevant for understanding a number of chemical substances and compounds. The reason Glauber’s name still sounds familiar to us today is that he discovered how to artificially create hydrate sodium sulfate, a compound highly relevant for glassmaking, which Glauber called sal mirabile.[3] This white crystalline solid is still commonly known as Glauber salt, and can be bought from online chemists to intensify the colours of textile dyes.[4]

Frontispice to the English translation of Glauber's work, containing a recipe for sal miracle: "The works of the highly experienced and famous chymist, John Rudolph Glauber," transl. Christopher Packe, London: Thomas Milbourne, 1689
Frontispice to the English translation of Glauber’s work, containing a recipe for sal mirabile.

Glauber salt was, and is, of great use in the making of glass, where an alkaline is necessary to lower the melting point of the ingredients for glass and to obtain good results. Before the discovery of Glauber salt, or soda ash (sodium carbonate) that had been extracted from the ashes of plants, was commonly used. The downside of using soda ash though, as Herman Boerhaave (1668-1738) put it in his Theory of Chemistry, was that ‘the ashes of plants us’d herein, also vary the goodness of glass.’[5] The relative ease with which Glauber salt could be made (Glauber’s own recipe!) requires nothing more than plain salt, water, a retort and a fire. Its purity ensured a more stable glass quality than soda ash. But Glauber and his contemporaries thought that his newly discovered salt was miraculous for another reason: its perceived therapeutic qualities. Glauber salt was long used as a laxative and a styptic.[6]

Sodium sulfate or Glauber salt
Sodium sulfate or Glauber salt

These useful applications meant that the popularity of Glauber salt in the eighteenth and nineteenth century was enormous, as also shown by the numerous recipes for it in medical and chemical handbooks. In a manuscript with lecture notes, a student of the Leiden professor of chemistry Gaub (1705-1780) devoted almost ten pages to the description of three processes to create Glauber Salt.[7] Reversing these recipes, the Dutch apothecary Petrus Johannes Kasteleyn (1746-1794), who aimed to stimulate the public’s interest in chemistry in the eighteenth century, wrote in his Chemical exercises for the lovers of chemistry in general, and the apothecaries, producers, and dealers in particular that through chemical analysis he had found that  ’16 ounces of pure Glauber salt consist of 2 ounces of vitriolic acid, and 3.5 ounces of pure alkali.[8]

From the early twentieth century onwards, the use of Glauber salt in medicine declined as safer alternatives were discovered, but it is still widely used industrially today. The story of the recipe for Glauber salt shows us the serendipity of research: while looking for something entirely different–the Philosopher’s Stone–Glauber discovered a substance that would become widely used in medicine, crafts and industry for centuries to come.


[1] AAR (Amsterdamse Archeologische Rapporten) 61, 2011, p. 44. The glasshouse was housed at the Rozengracht 1657 and 1679.

[2] D. Von Kerssenbrock-Krosigk, Glass of the alchemists : lead crystal-gold ruby, 1650-1750 (Corning, NY: Corning Museum of glass, 2008), p. 17.

[3] For Glauber’s recipe for sal mirabile, see The works of the highly experienced and famous chymist, John Rudolph Glauber, trans. Christopher Packe (London: Thomas Milbourne, 1689), p. 225.

[4] http://www.stoftotverven.nl/Glauberzout-500-gram; http://www.dharmatrading.com/chemicals/glaubers-salt.html

[5] H. Boerhaave, Elementa chemiae, quae anniversario labore docuit in publicis, privatisque scholis. 2 vols, vo.l. I, Leiden: Isaak Severinus, 1732, p. 183.

[6] Pinkhof, ‘Glauberzout als Bloedstelpend Middel,’ Nederlands Tijdschrift voor Geneeskunde, 1897, 41, pp. 297-8.

[7] H.D. Gaub, “Chemiae praxis. Notes of lectures by an unnamed student. Produced in Leyden.”, z.d. WMS 4  MS.2479, Wellcome Library, London, pp. 67-79.

[8] P.J. Kasteleyn, ‪Chemische oefeningen voor de beminnaars der scheikunst in ‘t algemeen, en de apothekers, fabriekanten en trafiekanten in ‘t bijzonder, vol. 2 (Amsterdam: ‪A. J. van Toll, 1872), p. 83. For more on Kastelyn’s educational purposes, see L. Roberts, ‘P. J. Kasteleyn and the “Oeconomics” of Dutch Chemistry,’ Ambix 53, 3 (2006): 255-272.