Category Archives: History of Chemistry

Microscopes & Submarines

The development of #histSTM in the early decades of the Dutch Republic, or Republic of the Seven United Netherlands, to give it its correct name, was quite extraordinary. Alongside the development of cartography and globe making, the most advanced in the whole of Europe, there were important figures such as the engineer, mathematician and physicist, Simon Stevin, the inventors of the telescope Hans Lipperhey and Jacob Metius, the mathematical father and son Rudolph and Willebrord Snel van Royan and Isaac Beeckman one of the founders of the mechanical philosophy in physics amongst others. However, one of the most strange and wonderful figures in the Netherlands during this period was, without doubt, the engineer, inventor, (al)chemist, optician and showman Cornelis Jacobszoon Drebbel (1571–1631).


Source: Wikimedia Commons

Drebbel is one of those larger than life historical figures, where it becomes difficult to separate the legends and the myths from the known facts, but I will try to keep to the latter. He was born to Jacob Drebbel an Anabaptist in Alkmaar in the province of North Holland. He seems not to have received much formal education but in about 1587 he started attending the Academy of the printmaker, draftsman and painter Hendrick Goltzius (1558–1617) in Haarlem also in North Holland.


Hendrick Goltzius – Self-Portrait, c. 1593-1594 – Google Art Project Source: Wikimedia Commons

Goltzius was regarded as the leading engraver in the Netherlands during the period and he was also an active alchemist. Drebbel became a skilled engraver under Goltzius’ instruction and also acquired an interest in alchemy. In 1595 he married Sophia Jansdochter Goltzius, Hendrick’s younger sister. They had at least six children of which four survived into adulthood. The legend says that Sophia’s prodigal life style drove Drebbel’s continual need to find better sources for earning money.


Drebbel’s town plan of Alkmaar 1597 Source: Wikimedia Commons

Drebbel initially worked as an engraver, cartographer and painter but somewhere down the line he began to work as an inventor and engineer.


Astronomy [from the series The Seven Liberal Arts]. Engraving by Drebbel Source: Wikimedia Commons

Not surprisingly, for a Netherlander, he a turned to hydraulic engineering receiving a patent for a water supply system in 1598. In 1600 he built a fountain at the Noorderpoort in Middelburg and at the end of his life living in England he was involved in a plan to drain the Fens. At some point, possibly when he was living in Middelburg, he learnt the craft of lens grinding, which would play a central roll in his life.

Also in 1598 he acquired a patent for Perpetuum mobile but which he, however, had not invented. The so-called Perpetuum mobile was a sort of clock, which was in reality powered in changes by the air temperature and air pressure had actually been invented by Jakob Dircksz de Graeff (1571–1638), an influential politician and natural philosopher, who was a friend of both Constantijn Huygens and René Descartes, and Dr Pieter Jansz Hooft (1574/5–1636) a politician, physician and schoolteacher.


Jakob Dircksz de Graeff Source: Wikimedia Commons


Pieter Jansz Hooft (1619), Attributed to Michiel van Mierevelt Source: Wikimedia Commons

Drebbel not only patented the Perpetuum mobile but also claimed to have invented it. His increasing reputation driven by this wonder machine earned his an invitation to the court of King James VI &I in London as the guest of the crown prince Henry in 1604. When on the court in London the Queen accidentally broke the Perpetuum mobile, Drebbel was unable to repair it.


The barometric clock of Cornelis Drebbel patented in 1598 and then known as “perpetuum mobile”. Print by Hiesserle von Choda (1557-1665) Source: Wikimedia Commons

At the court in London he was responsible for staging masques, a type of play with poetry, music, dance, and songs that was popular in the sixteenth and seventeenth centuries. He designed and built the stage sets and wonderful machines to enchant the audiences. Drebbel was by no means the only scientist-engineer to be employed to stage such entertainments during the Early Modern Period but he appears to have been very good at it. It was almost certainly Drebbel, who through his contacts imported from the Netherlands the first ever telescope to be seen in England, which was presented to James at the high point of a masque in 1609. He also built a magic lantern and a camera obscura with which he also entertained the members of the court.

Drebbel’s reputation grew to the point where he received an invitation to the court of the Holly Roman Empire, Rudolf II, in Prague in October 1610. Rudolf liked to surround himself with what might be termed wonder workers. Amongst those who had served in this capacity in Prague were Tycho Brahe, John Dee, Edward Kelley, Johannes Kepler and Jost Bürgi. There are no reports of any interactions between Drebbel and either Kepler or Bürgi, who were all on the court of Rudolf at the same time. In Prague he once again functioned as a court entertainer or showman.


AACHEN, Hans von – Portrait of Emperor Rudolf II Source: Wikimedia Commons

Rudolf was deposed by his brother Archduke Mathias in 1611and Drebbel was imprisoned for about a year. Following the death of Rudolf in 1612, Drebbel was released from prison and returned to London. Here, however, his situation was not as good as previously because Henry, his patron, had died in 1612. He kept his head above water as a lens grinder and instrument maker.

As a chemist Drebbel published his best-known written work Een kort Tractaet van de Natuere der Elemente (A short treatise of the nature of the elements) (Haarlem, 1621).


He was supposedly involved in the invention of the explosive mercury fulminate, Hg(CNO)2, but this is disputed. He also developed other explosive mixtures. He invented a chicken incubator with a mercury thermostat to keep it at a constant, stable temperature. This is one of the earliest feedback controlled devices ever created. He also developed and demonstrated a functioning air conditioning system.


Error-controlled regulator using negative feedback, depicting Cornelius Drebbel’s thermostat-controlled incubator of circa 1600. Source: Wikimedia Commons

He didn’t himself exploit one of his most successful discoveries, one that he made purely by accident. He dropped a flask of aqua regia (a mixture of nitric and hydrochloric acid, normally used to dissolve gold) onto a tin windowsill and discovered that stannous chloride (SnCl2) makes the colour of carmine (the red dye obtained from the cochineal insect) much brighter and more durable. Although Drebbel didn’t exploit this discovery his daughters Anna and Catherina and their husbands the brothers, Abraham and Johannes Sibertus Kuffler (a German inventor and chemist) did, setting up dye works originally in Leiden and then later in Bow in London. The colour was known as Colour Kuffler of Bow Dye and was very successful. Kuffler later continued his father-in-law’s development of self-regulating ovens that he demonstrated to the Royal Society.

In the early 1620s Constantijn Huygens, the father of Christiaan, came to London on a diplomatic mission. He made the acquaintance of Drebbel, who demonstrated his magic lantern and his camera obscura for the Dutch diplomat. Huygens was much impressed by his landsman and for a time became his pupil learning how to grind lenses, a skill that he might have passed onto his sons.


Constantijn Huygens (1596-1687), by Michiel Jansz van Mierevelt. Source: Wikimedia Commons

It is not known, who actually invented the microscope and it’s more than likely that the principle of the microscope was discovered by several people, all around the same time, who like Galileo looked through their Galilean or Dutch telescope the wrong way round. What, however, seems to be certain is that Drebbel is the first person known to have constructed a Keplerian telescope, that is with two convex lenses rather than a concave and a convex lens. As with all of his other optical instruments, Drebbel put on microscope demonstration introducing people to the microscopic world, as always the inventor as showman.

Drebbel’s most famous invention was without doubt his submarine. This is claimed to be the first-ever navigable submarine but has become the stuff of legends, how much of story is fact is difficult to assess. His submarine consisted of a wooden frame covered in leather, and one assumes waterproofed in someway; it was powered by oar.


Artistic representation of Drebbel’s submarine, artist unknown Source: Wikimedia Commons

It had bladders inside that were filled with water to enable the submarine to submerge; the bladders were emptied when the vessel was required to surface. In total between 1620 and 1624 Drebbel built three different vessels increasing in size. The final submarine had six oars and could carry up to sixteen passengers. Drebbel gave public demonstrations with this vessel on the river Thames. According to reports the vessel dived to a depth of four to five metres and remained submerged for three hours traveling from Westminster and Greenwich and back again. Assuming the reports to be true, there has been much speculation as to how fresh air was supplied inside the closed vessel. These speculations include a mechanical solution with some form of snorkel as well as chemical solutions with some sort of chemical apparatus to generate oxygen. It is also reported that Drebbel took King James on a dive under the Thames. Despite all of this Drebbel failed to find anybody, who would be prepared to finance a serious use of his submarine.

In the later 1620s Drebbel served the Duke of Buckingham as a military advisor but his various suggestions for weapons proved impractical and failed, the British blaming  the inventor and Drebbel blaming the English soldiers, finally ruining whatever reputation he still had. As already stated above towards the end of his life he was supposedly involved in a scheme to drain the Fens but the exact nature of his involvement remains obscure. Drebbel died in financial straights in 1633 in London, where he was scraping a living running a tavern on the banks of the Thames.

















Filed under History of Alchemy, History of Cartography, History of Chemistry, History of Optics, History of Technology, Renaissance Science

Revealing the secrets of the fire-using arts

During the Middle Ages it was common practice for those working in the crafts to keep the knowledge of their trades secret, masters passing on those secrets orally to new apprentices. This protection of trade secrets, perhaps, reached a peak during the Renaissance in the glassmaking centre of Venice, where anybody found guilty of revealing the secrets of the glassmaking was sentenced to death. Although there were in some crafts manuscripts, which made it into print, describing the work processes involved in the craft these were of very limited distribution. All of this began to change with the invention of moving type book printing. Over the sixteenth and seventeenth centuries printed books began to appear describing in detail the work processes of various crafts. I have already written a post about one such book, De re metallica by Georgius Agricola (1494–1555). However, Agricola’s book was not the first printed book on metallurgy that honour goes to the Pirotechnia of Vannoccio Biringuccio published posthumously in Italian in 1540. Agricola was well aware of Biringuccio’s book and even plagiarised sections of it in his own work.


Title page, De la pirotechnia, 1540, Source: Science History Museum via Wikipedia Commons

Whereas Agricola was himself not a miner or metal worker but rather a humanist physician, whose knowledge of the medieval metallurgical industry was based on observation and questioning of those involved, Biringuccio, as we will see, spent his whole life engaged in one way or another in that industry and his book was based on his own extensive experiences.

Born in Siena 20 October 1480 the son of Lucrezia and Paolo Biringuccio, an architect.


Siena 1568

As a young man Vannoccio travelled throughout Italy and Germany studying metallurgical operations. In Siena he was closely associated with the ruling Petrucci family and after having run an iron mine and forge for Pandolfo Petrucci, he was appointed to a public position at the arsenal and in 1513 director of the mint.


Petrucci coat of arms Source: Wikimedia Commons

He was exiled from Siena in 1516 after the Petruccis fell from power and undertook further travels throughout Italy and visited Sicily in 1517. In 1523 the Petruccis were reinstated and Vannoccio returned to Siena and to his position in the arsenal. In 1526 the Petruccis fell from power again and he was once again forced to leave his hometown. He worked in both the republics of Venice and Florence casting cannons and building fortifications. In 1531 in a period of political peace he returned once more to Sienna, where he was appointed a senator, and architect and director of building construction. Between 1531 and 1535 he cast cannons and constructed fortification in both Parma and Venice. In 1536 he was offered a job in Rome and after some hesitation accepted the post of head of the papal foundry and director of papal munitions. It is not known when or where he died but there is documentary evidence that he was already dead on 30 April 1539.

His Pirotechnia was first published posthumously in Venice in 1540, it was printed by Venturino Roffinello, published by Curtio Navo and dedicated to Bernardino di Moncelesi da Salo. Bernardino is mentioned both in the book’s preface as well as in the text. The Pirotechnia consists of ten books, each one dealing with a separate theme in the world of Renaissance metallurgy, transitioning from the wining of metal ores, over their smelting to the use of the thus produced materials in the manufacture of metal objects and dealing with a whole host of side topic on the way. Although by no means as lavishly illustrated as De re metallica, the book contains 84 line drawings** that are as important in imparting knowledge of the sixteenth century practices as the text.

Book I, is titled Every Kind of Mineral in General, after a general introduction on the location of ores it goes on the deal separately with the ores of gold, silver, copper, lead, tin and iron and closes with the practice of making steel and of making brass.



Book II continues the theme with what Biringuccio calls the semi-minerals an extensive conglomeration of all sorts of things that we wouldn’t necessarily call minerals. Starting with quicksilver he moves on to sulphur then antimony, marcasite (which includes all the sulphide minerals with a metallic luster), vitriol, rock alum, arsenic, orpiment and realgar.



This is followed by common salt obtained from mine or water and various other salts in general then calamine Zaffre and manganese. The book now takes a sharp turn as Biringuccio deals with the loadstone and its various effects and virtues. His knowledge in obviously not first hand as he repeats the standard myths about loadstones losing their power and virtue in the presence of diamonds, goat’s milk and garlic juice. He now move on to, ochre, bole, emery, borax, azure and green azure. Pointing out that many of the things he has dealt with are rocks rather than metals he now introduces rock crystal and all important gems in general before closing the book with glass.


Book III covers the assaying and smelting metal ores concentring on silver, gold and copper.





Book IV continues with a related theme, the various methods for separating gold from silver.



Having covered separation of gold and silver Book V covers the alloys of gold, silver, copper, lead and tin.

Following the extraction of metals, their assays, separation and alloys, Book VI turns to practical uses of metals: the art of casting in general and particular.







Book VII the various methods of melting metals.







Having dealt with the casting of bells and cannons in Book VII, Book VIII deals the small art of casting.


Book IX is a bit of a mixed bag titled, Concerning the Procedure of Various Operations of Fire. The book opens with a very short chapter on alchemy. Biringuccio has already dealt with alchemical transmutation fairy extensively in Book I when discussing the production of gold. He doesn’t believe in it: These men [alchemists] in order to arrive at such a port have equipped their vessels with sails and hard-working oarsmen and have sailed with guiding stars, trying every possible course, and, finally submerged in the impossible (according to my belief) not one of them to my knowledge has yet come to port. In Book XI he acknowledges that although transmutation doesn’t work, alchemists have developed many positive things: …it is surely a fine occupation, since in addition to being very useful to human need and convenience, it gives birth every day to new and splendid effects such as the extraction of medicinal substances, colours and perfumes, and an infinite number of compositions of things. It is known that many arts have issued solely from it; indeed, without it or its means it would have been impossible for them ever to have been discovered by man except through divine revelation.The next chapter deal briefly with sublimation and very extensively with distillation both of which he acknowledges are products of the alchemists.




He now takes a sharp turn left with a chapter on Discourse and Advice on How to Operate a Mint Honestly and with Profit. This is followed with chapters on goldsmith, coppersmith, ironsmith and pewterer work, leading on to chapters on wire drawing, preparing gold for spinning, removing gold from silver and other gilded objects, and the extraction of every particle of gold and silver from slags of ore.



The book closes with making mirrors from bell metal and three chapters on working with clay.


Book X closes out Biringuccio’s deliberations with essays on making saltpetre and gunpowder, then moving on to the uses of gunpowder in gunnery, military mining, and fireworks, the later in both military and civil circumstances.



Biringuccio’s efforts proved successful with Italian editions of the book appearing in 1540 (Sienna), 1550 (Venetia), 1558/9 (Venegia), 1559 (Venetia), 1678 (Bologna), and 1914 (Barese). French editions appeard in 1556 (Paris), 1572 (Paris), 1627 (Rouen), and 1856 (Paris). A German edition appeared in 1925 (Braunschweig). There were only partial translation into English in 1555 (London) and 1560 (London). The first full English translation was made by Martha Teach Gnudi & Cyril Stanley Smith with notes and an introduction in 1941 (New Haven), which was republished by Dover Books in New York in 1990. It is the Dover edition that forms the basis of this blog post.

Biringuccio’s Pirotechnia is an important publication in the histories of technology, metallurgy, inorganic chemistry and the crafts and trades in general and deserves to be much better known.

**I have only chosen a selection of the drawings. On some subjects such as the use of bellows Biringuccio brings wholes rows of illustrations to demonstrate the diverse methods used.








Filed under History of Chemistry, History of Technology, Renaissance Science

How Chemistry came to its first journal – and a small-town professor to lasting prominence

Being fundamentally a lazy sod I am always very pleased to welcome a guest blogger to the Renaissance Mathematicus, because it means I don’t have to write anything to entertain the mob. Another reason why I am pleased to welcome my guest bloggers is because they are all better educated, better read and much more knowledgeable than I, as well as writing much better than I ever could, meaning I get princely entertained and educated by them. Todays new guest blogger, Anna Gielas, maintains the high standards of the Renaissance Mathematicus guests. Anna, who’s a German studying in Scotland whereas I’m an English man living in Germany, helps me to put together Whewell’s Gazette the #histSTM weekly links list. I’ll let her tell you somewhat more about herself.

 I’m a doctoral candidate at the University of St Andrews (Dr Aileen Fyfe and Prof Frank James from the Royal Institution of Great Britain are my supervisors) and I study the editorship and the establishment of early scientific journals in Britain and the German lands. I focus on the decades between 1760 and 1840 because this was the time when commercial (as opposed to society-based) science periodicals took off and became a central means of scientific communication and knowledge production

 As you can see Anna is an expert for the history of scientific journals and her post honours the 200th anniversary of the death Lorenz Crell, 7 June 1816, who edited and published the world’s first commercial journal devoted exclusively to chemistry. Read and enjoy.




In early February 1777, the famous Swiss physiologist Albrecht von Haller received a letter from an obscure small-town professor named Lorenz Crell. Crell had studied medicine, travelled Europe and returned to his hometown, where he succeeded his former professor of medicine at the local university.

The young professor asked Haller for feedback on a few essays he had submitted anonymously. Haller’s favourable comments encouraged Crell not only to reveal his name but also his risky plan: “I have a chemical journal in the works”, Crell announced to Haller in February 1777.

Lorenz Crell Source: Wikimedia Commons

Lorenz Crell
Source: Wikimedia Commons

The thirty-three year old professor had hardly any experiences with publishing, let alone with editing a learned journal. Yet his periodical would go on to become the first scientific journal devoted solely to chemical research—and would influence the course of chemical research throughout the German speaking lands.

In February of 1777—roughly one year before the inaugural issue of his Chemisches Journal appeared—things looked rather dire for Crell. At this time, there were essentially two professional groups in the German speaking lands devoted to chemical endeavours: university professors and apothecaries. The core of professorial work—and the task they were paid for—was teaching. And chemistry was taught as part of the medical curriculum. Apothecaries, in turn, focused mainly on producing remedies. Neither profession was based on chemical research. Experimentation would remain secondary until the nineteenth century.

So whom did Crell expect to pick up his periodical? He hoped to garner the attention of the eminent Andreas Sigismund Marggraf and his peers. Marggraf was the first salaried chemist at the Royal Prussian Academy of Sciences in Berlin. Like most of the leading chemical researchers, Marggraf was an apprenticed apothecary. He had audited lectures and seminars at the University of Halle, an epicentre of the Enlightenment, but he never graduated. Before taking on his post at the Academy, Marggraf earned his living through the apothecary shop that he had inherited from his father, the “Apotheke zum Bären” (Bear’s Pharmacy) on Spandauer Straße in Berlin.

Hoping that renowned chemical experimenters like Marggraf would pick up Crell’s journal was one thing—catching their attention and actually persuading them to contribute to the periodical a very different one. But Crell, it appears, had a plan. Later in 1777 he contacted Friedrich Nicolai, a famous publisher and bookseller of the German Enlightenment, and asked for the honour of reviewing a few chemical books for Nicolai’s Allgemeine deutsche Bibliothek (ADB). Crell picked a good moment to do so: in 1777, the ADB experienced record sales. But the editor-to-be approached Nicolai without any letter of introduction, which according to the mores of his times, the Prussian Aufklärer could have easily interpreted as impudence. Nicolai apparently saw moxie where others might have seen brazenness: the publisher commissioned reviews from Crell within days of receiving his letter. Within roughly two months, from November 1777 until mid-January 1778, Crell submitted no less than eleven pieces for Nicolai’s famous periodical. “I still owe you five reviews which shall follow quickly”, he wrote to the Prussian publisher in January. Nicolai received them by February.

Title page from the Chemisches Journal for 1778 Source: Wikimedia Commons

Title page from the Chemisches Journal for 1778
Source: Wikimedia Commons

Crell was aware that Nicolai had close ties to leading chemical investigators. The publisher was about to become an extraordinary member of the Prussian Academy of Sciences and chemical researchers such as Johann Christian Wiegleb and Johann Friedrich Gmelin contributed to the ADB. Wiegleb was a pharmacist who expanded his laboratory in Langensalza to teach chemistry. Wiegleb’s students lived, learned, and—most importantly—researched at his Privat-Institut. Johann Friedrich Göttling was one of Wiegleb’s pupils—as was the English industrialist Matthew Boulton.

Crell tried to tap into this network when he first contacted Nicolai. Maybe he even hoped to recruit the renowned chemical researchers for the inaugural issue of his Chemisches Journal. But the editor had to pace himself: the first issue of his periodical was almost entirely authored by himself and Johann Christian Dehne, a close friend and physician from a neighbouring village.

Ultimately, Crell’s concerted efforts as a regular contributor to the ADB and the editor of the Chemisches Journal paid off: all three—Wiegleb, Gmelin and Göttling—submitted articles for the second issue of Crell’s novel journal. Throughout the years many other joined them, including the Irish chemist Richard Kirwan, the Scottish researcher Joseph Black and the German Martin Heinrich Klaproth, the first professor of chemistry at the University of Berlin. Andreas Sigismund Marggraf, however, never published in Crell’s journal, maybe due to health issues following a stroke.

Crell devoted decades of his life to his journals. Within nearly 27 years he published nine periodicals, the longest-running and most famous of which is the Chemische Annalen (1784-1804). It was here that the German chemists debated (and death-bedded) phlogiston. During a busier year, such as 1785, Crell published over 2,000 pages of chemical facts, findings and flapdoodle.

Today, some scientists and historians belittle his role in chemistry, arguing that Crell did not contribute anything crucial to science. To judge Crell by what he did not achieve in his laboratory is to present science as a solitary undertaking, tucked away in labs. But if we acknowledge that science is a joint endeavour, based on communication, on-going exchange and discussions, Crell’s contribution appears vital.

According to the Berkeley-historian Karl Hufbauer, Crell’s Chemische Annalen was crucial in the formation of the German chemical community. Even more, Crell provided German and European researchers with an instrument for the production of chemical knowledge.

Today is the 200th anniversary of his death. Let’s use the date to commemorate all the editors throughout the centuries who spent countless hours at their desks—and contributed to the giant’s shoulders on which we stand today.




Filed under Early Scientific Publishing, History of Chemistry, History of science


DO IT! is the title of a book written by 1960s Yippie activist Jerry Rubin. In the 1970s when I worked in experimental theatre groups if somebody suggested doing something in a different way then the response was almost always, “Don’t talk about it, do it!” I get increasingly pissed off by people on Twitter or Facebook moaning and complaining about fairly trivial inaccuracies on Wikipedia. My inner response when I read such comments is, “Don’t talk about it, change it!” Recently Maria Popova of brainpickings posted the following on her tumblr, Explore:

The Wikipedia bio-panels for Marie Curie and Albert Einstein reveal the subtle ways in which our culture still perpetuates gender hierarchies in science. In addition to the considerably lengthier and more detailed panel for Einstein, note that Curie’s children are listed above her accolades, whereas the opposite order appears in the Einstein entry – all the more lamentable given that Curie is the recipient of two Nobel Prizes and Einstein of one.

How ironic given Einstein’s wonderful letter of assurance to a little girl who wanted to be a scientist but feared that her gender would hold her back. 

When I read this, announced in a tweet, my response was a slightly ruder version of “Don’t talk about it, change it!” Within minutes Kele Cable (@KeleCable) had, in response to my tweet, edited the Marie Curie bio-panel so that Curie’s children were now listed in the same place as Einstein’s. A couple of days I decided to take a closer look at the two bio-panels and assess Popova’s accusations.

Marie Curie c. 1920 Source Wikimedia Commons

Marie Curie c. 1920
Source Wikimedia Commons

The first difference that I discovered was that the title of Curie’s doctoral thesis was not listed as opposed to Einstein’s, which was. Five minutes on Google and two on Wikipedia and I had corrected this omission. Now I went into a detailed examination, as to why Einstein’s bio-panel was substantially longer than Curie’s. Was it implicit sexism as Popova was implying? The simple answer is no! Both bio-panels contain the same information but in various areas of their life that information was more extensive in Einstein’s life than in Curie’s. I will elucidate.

Albert Einstein during a lecture in Vienna in 1921 Source: Wikimedia Commons

Albert Einstein during a lecture in Vienna in 1921
Source: Wikimedia Commons

Under ‘Residences’ we have two for Curie and seven for Einstein. Albert moved around a bit more than Marie. Marie only had two ‘Citizenships’, Polish and French whereas Albert notched up six. Under ‘Fields’ both have two entries. Turning to ‘Institutions’ Marie managed five whereas Albert managed a grand total of twelve. Both had two alma maters. The doctoral details for both are equal although Marie has four doctoral students listed, whilst Albert has none. Under ‘Known’ for we again have a major difference, Marie is credited with radioactivity, Polonium and Radium, whereas the list for Albert has eleven different entries. Under ‘Influenced’ for Albert there are three names but none for Marie, which I feel is something that should be corrected by somebody who knows their way around nuclear chemistry, not my field. Both of them rack up seven entries under notable awards. Finally Marie had one spouse and two children, whereas Albert had two spouses and three children. In all of this I can’t for the life of me see any sexist bias.

Frankly I find Popova’s, all the more lamentable given that Curie is the recipient of two Nobel Prizes and Einstein of one, comment bizarre. Is the number of Nobel Prizes a scientist receives truly a measure of their significance? I personally think that Lise Meitner is at least as significant as Marie Curie, as a scientist, but, as is well known, she never won a Nobel Prize. Curie did indeed win two, one in physics and one in chemistry but they were both for two different aspects of the same research programme. Einstein only won one, for establishing one of the two great pillars of twentieth-century physics, the quantum theory. He also established the other great pillar, relativity theory, but famously didn’t win a Nobel for having done so. We really shouldn’t measure the significance of scientists’ roles in the evolution of their disciplines by the vagaries of the Nobel awards.



Filed under History of Chemistry, History of Physics, History of science, Ladies of Science

The Phlogiston Theory – Wonderfully wrong but fantastically fruitful

There is a type of supporter of gnu atheism and/or scientism who takes a very black and white attitude to the definition of science and also to the history of science. For these people, and there are surprisingly many of them, theories are either right, and thus scientific, and help the progress of science or wrong, and thus not scientific, and hinder that progress. Of course from the point of view of the historian this attitude or stand point is one than can only be regarded with incredulity, as our gnu atheist proponent of scientism dismisses geocentrism, the phlogiston theory and Lamarckism as false and thus to be dumped in the trash can of history whilst acclaiming Copernicus, Lavoisier and Darwin as gods of science who led as out the valley of ignorance into the sunshine of rational thought.

I have addressed this situation before on more than one occasion but as a historian of science I think that it’s a lesson that needs to be repeated at regular intervals. Because it is the American Chemical Society’s “National Chemistry Week 2015” I shall be re-examining the Phlogiston Theory whose creator Georg Ernst Stahl was born on 22 October 1659 in Ansbach, which is in Middle Franconia just down the road from where I live.


Georg Ernst Stahl (1660–1734) Source: Wikimedia Commons

Stahl had a fairly conventional career, studying medicine at Jena University from 1679 to 1684. 1687 he became court physician to the Duke of Sachen-Weimar and in 1694 he was appointed professor of medicine at the newly founded University of Halle, where he remained until 1715 when he became personal physician to Friedrich Wilhelm I, King of Prussia. Stahl like most chemists in the Early Modern Period was a professional physician, chemistry only existing within the academic context as a sub-discipline of medicine.

To understand the phlogiston theory we need to go back and take a brief look at the development of the theory of matter since the ancient Greeks. Empedocles introduced the famous four-element theory, Earth, Water, Air and Fire, in the fifth century BCE and this remained the basic theory in Europe until the Early Modern Period. In the ninth century CE Abu Mūsā Jābir ibn Hayyān added Sulphur and Mercury to the four-elements as principles, rather than substances, to explain the characteristics of the seven metals. In the sixteenth century CE, Paracelsus took over al- Jābir’s Sulphur and Mercury adding Salt as his tria prima to explain the characteristics of all matter. In the seventeenth century, when Paracelsus’ influence was at its height, many alchemists/chemists adopted a five-element theory – Earth, Water, Sulphur, Mercury and Salt – dropping air and fire. Robert Boyle, in his The Sceptical Chymist (1661), threw out both the Greek four-element theory and Paracelsus’ tria prima, groping towards a more modern concept of element. We now arrive at the origins of the phlogiston theory.

The German Johann Joachim Becher (1635–1682), a physician and alchemist, was a big fan of Boyle and his theories and even travelled to London to learn at the feet of the master.


Johann Joachim Becher (1635-1682) Source: Wikimedia Commons

Like Boyle he rejected both the Greek four-element theory and Paracelsus’ tria prima, in his Physica Subterranea (1667) replacing them with a two-element theory Earth and Water with Air present just as a mixing agent for the two. However he basically reintroduced Paracelsus’ tria prima in the form of three different types of Earth.

  • terra fluida or mercurial Earth giving material the characteristics, fluidity, fineness, fugacity, metallic appearance
  • terra pinguis or fatty Earth giving material the characteristics oily, sulphurous and flammable
  • terra lapidea glassy Earth, giving material the characteristic fusibility

Stahl took up Becher’s scheme of elements concentrating on his terra pinguis, making it his central substance and renaming it phlogiston. In his theory all substances, which are flammable contain phlogiston, which is given up when they burn, the combustion ceasing when the phlogiston is exhausted. The classic demonstration of this was the combustion of mercury, which turns to ash, in Stahl’s terminology (mercuric oxide in ours). If this ash is reheated with charcoal the phlogiston is restored (according to Stahl) and with it the mercury. (In our view the charcoal removes the oxygen restoring the mercury). In a complex series of experiment Stahl turned sulphuric acid into sulphur and back again, explaining the changes once again through the removal and return of phlogiston. Through extension Stahl, an excellent experimental chemist, was able to explain, what we now know as the redox reactions and the acid-base reactions, with his phlogiston theory based on experiment and empirical observation. Stahl’s phlogiston theory was thus the first empirically based ‘scientific’ explanation of a large part of the foundations of chemistry. It is a classic example of what Thomas Kuhn called a paradigm and Imre Lakatos a scientific research programme.

Viewed with hindsight the phlogiston theory is gloriously, wonderfully and absolutely wrong in all of its aspects thus leading to the scorn with which it is viewed by our gnu atheist proponent of scientism, however they are wrong to do so. I prefer Lakatos’ scientific research programme to Kuhn’s paradigm exactly because it describes the success of the phlogiston theory much better. For Lakatos it’s irrelevant whether a theory is right or wrong, what matters are its heuristics. A scientific research programme that produces new facts and phenomena that fit within the descriptive scope of the programme has a positive heuristic. One that produces new facts and phenomena that don’t fit has a negative heuristic. Scientific research programmes have both positive and negative heuristics simultaneously throughout their existences, so long as the positive heuristic outweighs the negative one the programme continues to be accepted. This was exactly the case with the phlogiston theory.

Most European eighteenth-century chemist accepted and worked within the framework of the phlogiston theory and produced a great deal of new important chemical knowledge. Most notable in this sense are the, mostly British, so-called pneumatic chemists. Working within the phlogiston theory Joseph Black (1728–1799), professor for medicine in Edinburgh, isolated and identified carbon dioxide whilst his doctoral student Daniel Rutherford (1749–1819) isolated and identified nitrogen. The Swede Carl Wilhelm Scheele (1742–1786) produced, identified and studied oxygen for which he doesn’t get the credit because although he was first, he delayed in publishing his results and was beaten to the punch by Joseph Priestley (1733–1804), who had independently also discovered oxygen labelling it erroneously dephlogisticated air. Priestley by far and away the greatest of the pneumatic chemists isolated and identified at least eight other gases as well as laying the foundations for the discovery of photosynthesis, perhaps his greatest achievement.

Henry Cavendish (1731–1810) isolated and identified hydrogen, which he thought for a time might actually be phlogiston, before going on to make the most important discovery within the framework of the phlogiston theory, the structure of water. By a series of careful experiments Cavendish was able to demonstrate that water was not an element but a compound consisting of two measures of phlogiston (hydrogen) with one of dephlogisticated air (oxygen). With the same level of precision he also demonstrated that normal air consists of four parts of nitrogen to one of oxygen or better said not quite. He constantly found something he couldn’t identify present in one one-hundredth and twentieth of the volume of nitrogen. In the nineteenth century this would finally be identified as the gas argon.

All of these discoveries are to be counted to the positive heuristic of the phlogiston theory. What weighed heavily on the negative side is the fact that as the accuracy of measurement increased in the eighteenth century it was discovered that the ashes, of mercury for example, left behind on burning were heavier than the original substance being burnt. This was troubling as combustion was supposed to be the release of phlogiston. Some supporters of the theory even suggested negative phlogiston to explain this anomaly. This suggestion, which never caught on, gets particularly mocked today, something I find somewhat strange in an age that has had to accept anti-matter and is now being asked to accept dark matter and dark energy to explain known anomalies in current theories.

Ironically it was the discoveries of oxygen and the composition of water that gave Lavoisier the necessary building blocks to dismantle the phlogiston theory and build his own competing theory, which would in the end prove successful and commit the phlogiston theory to the scrap heap of the history of chemistry. However one should never forget that it was exactly this theory that delivered him the tools he needed to do so. As I wrote in my sub-title even a theory that is wonderfully wrong can be fantastically fruitful and should be treated with respect when viewed with hindsight.



Filed under History of Chemistry, History of science, Myths of Science

A breath of fresh air

I’m supposed to be preparing a lecture on the eighteenth-century pneumatic chemists and I noticed this morning that today is the birthday of Stephen Hales who was responsible for a small invention that made pneumatic chemistry possible, so I decided to write a post about him.

Stephen Hales, aged 82, by J.McArdell after T. Hudson Source: Wikimedia Commons

Stephen Hales, aged 82, by J.McArdell after T. Hudson
Source: Wikimedia Commons

Hales, who is largely unknown today, except by experts, was regarded in the eighteenth century as one of the most important English natural historians with an international reputation amongst both natural historians and chemists. Born on the 17th September 1677 the tenth child and sixth son of Thomas Hales, heir to the Baronetcy of Beakesbourne and Brymore. As a younger son he was destined for the clergy and duly ordained in 1703 after graduating BA in 1700 at Corpus Christi College Cambridge. He obtained a fellowship in the same year and qualified MA in 1704. He remained in Cambridge until 1708 devoting his time to the study of the sciences mostly in tandem with William Stukeley, who would later become Newton’s physician. The two of them, being Cambridge men, studied Newton’s physics and astronomy as well as John Ray’s natural history.

Family connections found a curacy for Hales, which was the start of his long and successful church career, the high point of which was being appointed private chaplain to Princess Augusta, Dowager Princess of Wales and mother of George III in 1751. He was awarded a Doctor of Divinity by the University of Oxford in 1733 and is said to have turned down the offer of a canonry at Windsor from George II. Princess Augusta held him in such esteem that she had a monument erected to his memory in Westminster Abbey after his death in 1761, at the ripe old age of 83.

Stephen Hales monument Westminster Abbey Copyright: Westminster Abby

Stephen Hales monument Westminster Abbey
Copyright: Westminster Abby

However as stated above Hales was not only a successful pastor but also a very successful and important amateur natural historian making him an excellent example of the eighteenth- and nineteenth-century Anglican clergymen who devoted themselves to the study of the sciences making substantial advances to many fields. This historical phenomenon, of course, makes a mockery of the claims of the Gnu Atheists that religion and science are incompatible and that belief in God somehow hinders scientific thought.

Hales who became a member of the Royal Society in 1718 devoted his scientific studies to the circulatory systems of plants and animals. The results of his experimental studies on plants where published in his Vegetable Staticks. Hales determined the direction and force of sap flow in plants by inserting glass tubes into the stump of a vine with the branches cut off. He also inserted glass tubes containing water into the root systems of plants to determine the water absorption rate. Hales’ greatest achievement in his plant studies was to measure the transpiration rate. Through a series of complex and ingenious experiments he was able to determine how much water a plant perspired during its growing season and to demonstrate that this transpiration helped to draw water up through the roots.

Hales carries out similar experiments over many years on the circulatory systems of animals, which he published in his Haemastaticks in 1733. He later published both books together as his Statical Essays. Using the same method of inserting glass tubes into arteries and veins of various animals, Hales made the first ever blood pressure measurements. He then went on to measure cardiac output and compare pulse rates and blood pressure. These experiments were conducted on live animals without the benefits of sedation, which led his friend and neighbour, Alexander Pope, a dog lover, to condemn him for his cruelty to animals.

During his plant experiments Hales noted that air was expelled by his plants along with the water and he set out to devise methods to collect and measure the quantities of air thus produced. This is where Hales becomes interesting for the pneumatic chemists, who succeeded him in the eighteenth century and thus for my planned lecture. Hales devised a series of apparatuses to collect the air, which culminated in his invention of the pneumatic trough. A device that could be set to the general purpose of collecting gases separated from the generating apparatus.

Pneumatic Tr From Vegetable Staticks, opposite page 262 Source: Wikimedia Commons

Pneumatic Tr From Vegetable Staticks, opposite page 262
Source: Wikimedia Commons

The pneumatic trough would go on to be further developed by Henry Cavendish, William Brownrigg, Joseph Priestly and Antoine Lavoisier all of whom would use it in the discovery of various gasses, most notably hydrogen and oxygen; discoveries that would lead to the discovery of the composition of water and the beginnings of modern molecular chemistry. All of these researchers acknowledged their debt to Hales and his invention.

Throughout the late eighteenth century and the nineteenth century all of the great natural historians who laid the foundations of modern biology also acknowledge their debt to Hales for his pioneering work in both animal and plant physiology. It is only in the late nineteenth century that he began to be forgotten and to slide into obscurity; to become only the subject of study of specialist historians of science and no longer to be counted amongst the great natural historians.

As we have seen Hales was not just a brilliant theorist but also a very practical investigator designing and building complex experimental apparatus with which to conduct his researches. He applied this practical bent to the solution of an important social problem. His researches into air were a continuation of work begun in the seventeenth century by people such as Boyle and Hooke into air and its properties. One of the central concerns of these researches was the investigation of bad or foul airs, like those found in swamps, mines and enclosed spaces, such as prisons or ships. In fact Brownrigg’s development of Hales’ pneumatic trough was dedicated to this research. Hales was one of several researchers to invent a ventilator driven by bellows worked by hand and in larger versions by windmills to provide fresh air to enclosed spaces. Hales’ ventilators were a success and were widely employed in ships, prisons and mines.

Image of a Ventilation Bellows devised by Stephen Hales Source: Wellcome Library via Wikimedia Commons

Image of a Ventilation Bellows devised by Stephen Hales
Source: Wellcome Library via Wikimedia Commons

Addendum: 17 September 2020

Matthew Paskins on Facebook made the following important comment:

I think it’s an important part of Hales’ legacy that his celebrated ventilators were trialled by his contacts among slaveship owners, and that ventilation was advanced by supporters of slavery as a meliorist response to the conditions on board slaveships.

Hales is a classic example of those small scientific researchers, who upon investigation turn out not to be so small after all, who get lost and forgotten in our hagiographical presentation of the so-called giants of science. Next time you are at your doctors having your blood pressure checked spare a thought for the Reverend Stephen Hales the very first person to measure blood pressure.


Filed under History of Chemistry, History of medicine