Category Archives: History of science

If you are going to blazon out history of science ‘facts’ at least get them right

Today’s Torygraph has a short video entitled 10 Remarkable Facts about rainbows, at 57 seconds it displays the following text:

Until the 17th Century, no one had

the faintest idea what a rainbow

was, how it got there or what it was

made of…

This is, of course, simply not true. In the 14th century the Persian scholar Kamal al-Din Hasan ibn Ali ibn Hasan al-Farisi (1267–1319) gave the correct scientific explanation of the rainbow in his Tanqih al-Manazir (The Revision of the Optics). Almost contemporaneously the German scholar Theodoric of Freiberg (c. 1250–c. 1310) gave the same correct explanation in his De iride et radialibus impressionibus (On the Rainbow and the impressions created by irradiance). The two scholars arrived at their conclusion independently of each other but both of them did experiments involving the study of light rays passing through glass spheres full of water and both scholars were influenced by the optical theories of Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham. Unfortunately both explanations disappeared and it was in fact first in the 17th Century that the Croatian scholar Marco de Antonio Dominis (1560–1624) once again gave an almost correct explanation of the rainbow in his Tractatus de radiis visus et lucis in vitris, perspectivis et iride.

De Dominis' explanation of the rainbow Source: Wikimedia Commons

De Dominis’ explanation of the rainbow
Source: Wikimedia Commons


Filed under History of Optics, History of Physics, History of science, Myths of Science

How do we kill off myths of science zombies?

The Internet is a sort of cyberspace limbo where myths in the history of science, which have been debunked a long time ago, keep popping up on social media as #histsci zombies, the history of science undead. One such that has popped up to haunt me several times in recent weeks is the claim that Johannes Kepler murdered Tycho Brahe. This claim was at best ludicrous and, having been thoroughly debunked, is now just pathetic but continues to ghost through cyberspace as a #histsci zombie. Where does it come from, who put it into the world and did it ever have any validity?

Portrait of Kepler by an unknown artist, 1610 Source: Wikimedia Commons

Portrait of Kepler by an unknown artist, 1610
Source: Wikimedia Commons

After protracted negotiations and a return to Graz to fetch his family Johannes Kepler began to work with Tycho Brahe in Prague as his assistant in late 1600, not as his student as is often falsely stated. In September 1601, Tycho managed to negotiate an official position for Kepler at the Imperial Court of the German Emperor Rudolph II. Their partnership was however short lived, as Tycho died 24 October 1601. According to Kepler’s account Tycho had retained his urine during a banquet eleven days earlier, so as not to breach etiquette by leaving the table. Upon returning home he was unable to urinate, fell ill and falling into delirium died, apparently of some sort of urinary infection. This was the state of play in 1601 and remained unchanged until 1901.

Tycho Brahe Source: Wikimedia Commons

Tycho Brahe
Source: Wikimedia Commons

In 1901 Tycho’s body was exhumed and an autopsy carried out that failed to establish a cause of death. However when the corpse was reburied a sample of his beard hair was retained. In 1990 this hair sample was analysed and found to contain abnormally high levels of mercury, which led to the speculation that Tycho had died of mercury poisoning. At this point there was no real suspicion of murder but more speculation about an accidental mercury poisoning. Tycho was a Paracelsian pharmacist, who along with his observatory on Hven ran a pharmacy that produced various medical remedies. The speculation was that he had either poisoned himself whilst working with mercury, a not uncommon problem amongst pharmacists in the Early Modern period when mercury was used extensively in medicines, or that he had poisoned himself by taking one of his own mercury containing remedies.

The first real accusations that Tycho had been murdered, that is poisoned by another person, came with the publication in 2004 of Joshua & Anne-Lee Gilder’s book Heavenly Intrigue: Johannes Kepler, Tycho Brahe, and the Murder Behind One of History’s Greatest Scientific Discoveries. Put simply the Gilders claimed that Kepler had poisoned Tycho to gain access to his astronomical data. The first part of their book, in which they outline the lives of Tycho and Kepler is actually well researched and well written but it’s when they come to the cause of Tycho’s death the book goes of the rails.

The Gilder’s build a chain of speculative, unsubstantiated, circumstantial evidence leading to their conclusions that Tycho was murdered and Johannes Kepler did the evil deed. Any able defence lawyer or competent historian of science could dismantle the Gilder’s rickety and highly dubious chain of evidence without too much effort leading to a full acquittal of the accused. Unfortunately most book reviewers are neither lawyers nor historians of science and the popular press reviewers jumped on the book and swallowed the Gilder’s arguments hook, line and sinker. The result was that Kepler went from being a hero of the scientific revolution to being a perfidious murderer, almost overnight.

Fascinatingly, the furore created by the popular press led to an international team of experts being granted permission to exhume Tycho’s corpse and to carry out yet another autopsy. The noble Dane would not be allowed to rest in peace. This was duly done in 2010 and the corpse, or what was left of it, was subjected to a battery of scientific tests. All of this activity led to the popular science press publishing a cart load of articles, many of them on the Internet, asking if Kepler had indeed poisoned Tycho most of them skewing their articles strongly in the direction of a guilty verdict.

The international team of archaeologists, forensic anthropologists, pathologists and whoever took their time but in 2012 they finally published their results. There was not enough mercury present in the samples to have caused mercury poisoning and there were no other poison found in any quantities whatsoever. Tycho was not poisoned by Johannes Kepler or anybody else for that matter. A second independent team re-analysed the beard hairs taken from the corpse in 1901 and confirmed that there was not enough mercury present to have caused mercury poisoning.

The press outlets both popular and scientific that had trumpeted the Gilder’s highly dubious claims out into the world did not apply the same enthusiasm to reporting the negative results of the autopsy. Those lengthy articles in the Internet claiming, implying, insinuating or suggesting that Kepler had done for his employer were not updated, amended or corrected to reflect the truth and the Gilder’s book was not withdrawn from the market or consigned to the wastepaper basket, where it very definitely belongs. Below is part of the sales pitch for that book taken just a couple of hours ago from

But that is only half the story. Based on recent forensic evidence (analyzed here for the first time) and original research into medieval and Renaissance alchemy—all buttressed by in-depth interviews with leading historians, scientists, and medical specialists—the authors have put together shocking and compelling evidence that Tycho Brahe did not die of natural causes, as has been believed for four hundred years. He was systematically poisoned—most likely by his assistant, Johannes Kepler.

An epic tale of murder and scientific discovery, Heavenly Intrigue reveals the dark side of one of history’s most brilliant minds and tells the story of court politics, personal intrigue, and superstition that surrounded the protean invention of two great astronomers and their quest to find truth and beauty in the heavens above.

The result of all this is that historian of astronomy of the Early Modern period are forced to indulge in a game of historical Whac-A-Mole every time that somebody stumbles across one of those articles in the Internet and starts broadcasting on Twitter, Facebook or wherever that Johannes Kepler murdered Tycho Brahe.





Filed under History of Astronomy, History of science, Myths of 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

Galileo Super Star – Galileo Galilei to get Hollywood biopic

My attention was drawn recently to a Hollywood gossip website that announced that a movie is to be made of a play by Richard Goodwin about Galileo, The Hinge of the World. I must admit that my curiosity was piqued, not least because I had never heard of either Mr Goodwin or his play and I naturally wondered what his line on the Tuscan mathematicus would be. It turns out that Richard Goodwin is a former high power Washington political advisor and speechwriter who served Presidents Kennedy and Johnson as well as JFK’s brother Robert, not exactly the best qualifications for the author of a play about the history of science. My doubts about this particular production were only heightened upon reading the full original title of the play, The Hinge of the World: In Which Professor Galileo Galilei, Chief Mathematician and Philosopher to His Serene Highness the Grand Duke of Tuscany, and His Holiness Urban VIII, Bishop of Rome, Battle for the Soul of the World. This title does not bode well for a historically accurate account of Galileo’s clash with the Catholic Church. However I will reserve judgement, because as I say, I do not know the play. I have however ordered a second hand copy that is at this very moment wending its way from some distant land to my humble abode and when it arrives and I have perused it with due diligence, I will report back with a critical assessment.

A scene from the stage production of The Hinge of the World

A scene from the stage production of The Hinge of the World

The website report does however offer a précis of the contents of the soon to be film and this is possibly the most confused and inaccurate presentation of the affair and the events leading up to it that I have read in a very long time:

The film will stay true to the spirit of the play in that it will revolve around the one-time friends whose vehement disagreements led to the Church calling Galileo out for heresy when science started to challenge long-held beliefs.

Science had been challenging long held beliefs long before Galileo came along. Apart from anything else Galileo was tried for defending the truth of Copernicus’ heliocentric hypothesis and Copernicus had died twenty-one years before Galileo was born. Just for the record Copernicus was also by no means the first person to present science that challenged the Church’s long-held beliefs.

Just to be a little bit pedantic, the one-time friends, Galileo and Maffeo Barberini (Pope Urban VIII) only had one vehement disagreement.

During that time, around 1610, the Church was never questioned,…

Somebody really ought to have consulted a historian of the Catholic Church. People both inside and outside of the Church questioned it continuous, some with impunity, for example Galileo’s friend Paolo Sarpi, and some with dire consequences, such as Giordano Bruno.

…yet Galileo who had a passion, curiosity and a telescope started to question everything after logging what he was learning through his scientific research. He published much of his findings in a book that were disavowed by Pope Urban VIII and the Catholic Church. Despite delving into dangerous territory, Galileo continued his research into comets, tide movements until he was ultimately ordered by the Church to stop teaching his ideas.

 The above is just a historical train wreck. The book of Galileo’s disavowed by Urban VII and the Church was the Dialogue Concerning the Two Chief World Systems, published in 1632, which led directly to his trail and imprisonment in 1633. However, he was told to stop teaching the truth of the heliocentric hypothesis and only that, the rest of his ideas were not the subject of Church condemnation, in 1616 following the semi-public distribution of the so-called Letter to Castelli, much later published in expanded form, as the Letter to the Grand Duchess Christina. Also in 1616 Paul V was Pope and Maffeo Barberini was a mere Cardinal and still a good friend of Galileo’s.

 The brilliant scientist, engineer, physicist and mathematician who helped discover the law of the pendulum (which became the basis for modern-day clocks), who pushed scientists to conduct experiments to prove theorems, who continued the work of Nicolaus Copernicus to help understand our own universe and laid the groundwork for modern astronomy eventually lost his battle with the powerful Roman Catholic Church.

Again being somewhat pedantic, Galileo got the law of the pendulum wrong and modern day clocks stopped being pendulum driven some time ago. Also, and this is not so pedantic, it was Kepler, and not Galileo, who laid the groundwork for modern astronomy.

 He was tried for heresy and sentenced to imprisonment at the age of 68 where he would remain until his death nine years later at age 77.

A final point, that people love to forget because it rather spoils the image of Galileo the martyr, his sentence of imprisonment imposed for vehement suspicion of heresy, not heresy, was instantly commuted to house arrest, which whilst somewhat restrictive was by no means harsh.


All of this ties in rather nicely with an exchange that I took part in yesterday evening on twitter. Tim Skellet (@Gurdur) asked me and others, “what’s the very best, most comprehensive bio of Galileo, please?” My answer was, “I don’t think it exists. Read several: Wootton, Heilbron, Biagioli, Shea/Artigas.” I was not trying to be clever or awkward. I genuinely believe that if you wish to study any major figure out of the history of science then you should consult multiple sources, as all sources have their advantages and disadvantages. History is, to a large extent, a game of interpretation. There are facts but they only give a partial picture and it is the role or responsibility of the historian to complete that picture to the best of their ability. All historians have agendas and biases and to obtain a rounded picture it is always advisable to view the facts through the eyes of more than one historian.

Turning to the special case of Galileo, the two most recent complete biographies are J. L. Heilbron’s Galileo (OUP, 2010) and David Wootton’s Galileo: Watcher of the Skies (Yale University Press, 2010). Both are very good but differ in their interpretations and emphases. I wouldn’t recommend one over the other, so if you only want to read one then toss a coin or something. If you really want to get to grips with Galileo then read both. One important aspect of Wootton’s book is that he systematically dismantles the myth that Galileo was a good devout Catholic. This myth is trotted out regularly to make the Church look even worse for having persecuted him. Wootton demonstrates, I think convincingly, that Galileo was at best an indifferent Catholic and in no way the devout son of the Church that historical myth has made him out to be.

Although not a complete biography in the traditional sense I would also strongly recommend Mario Biagioli’s Galileo Courtier: The Practice of Science in the Culture of Absolutism (University of Chicago Press, 1993) Biagioli examines Galileo the social climber who uses his scientific discoveries to further his social status rather than for any idealistic belief in truth. Biagioli’s work is a useful complement to the more conventional scientific style of biography; what did Galileo discover and when. In what is effectively a second volume to his first book, Galileo’s Instruments of Credit: Telescopes, Images, Secrecy (University of Chicago Press, 2006), Biagioli explains how Galileo used the telescopes that he manufactured and the images that he produced to broker social advantages.

William R. Shea’s and Mariano Artigas’ Galileo in Rome: The Rise and Fall of a Troublesome Genius (OUP; 2003) just deals with the six extended visits that Galileo made to Rome, the home-base of the Church and the centre of political and social power in the period, during his lifetime. These include, his triumphal visit in 1611, as the author of his sensational Sidereus Nuncius, his visit in 1615-1616 and his failed attempt to prevent the Church condemning heliocentricity and finally his summons to his trial in 1633. By concentrating only on Galileo’s interactions with the Roman culture of the period the authors succeed in shedding light from a different angle on Galileo’s fateful path to his condemnation and fall.

At some point David Wootton joined the Twitter discussion and he recommended Pietro Redondi’s Galileo Heretic (Princeton University Press, 1992), a recommendation that I would one hundred pro cent endorse. Although Redondi’s central thesis, that Galileo was actually attacked by the Church for his atomism has, in the meantime, been largely refuted this is a superb book and still very much worth reading by anyone who wishes to learn about Galileo and the culture in which he lived and worked.

If you read all of the books that I have recommended above you should, by the time you have finished, have a fairly good all round picture of the life and work of Galileo Galilei and the footnotes and bibliographies will have given you lots of information for further reading. I will however close with a warning, do not read Michael White’s Galileo Antichrist: a Biography (Weidenfeld & Nicolson, 2007). I can deliver a comprehensive and profound review of White’s book in three words, “It is crap!”



Filed under History of Astronomy, History of science, Myths of Science, Renaissance Science

Isaac and the apple – the story and the myth

The tale of Isaac Newton and the apple is, along with Archimedes’ bath time Eureka-ejaculation and Galileo defiantly mumbling ‘but it moves’ whilst capitulating before the Inquisition, is one of the most widely spread and well known stories in the history of science. Visitors to his place of birth in Woolsthorpe get to see a tree from which the infamous apple is said to have fallen, inspiring the youthful Isaac to discover the law of gravity.

The Woolsthorpe Manor apple tree Source:Wikimedia Commons

The Woolsthorpe Manor apple tree
Source:Wikimedia Commons

Reputed descendants of the tree exist in various places, including Trinity College Cambridge, and apple pips from the Woolsthorpe tree was taken up to the International Space Station for an experiment by the ‘first’ British ISS crew member, Tim Peake. Peake’s overalls also feature a Principia patch displaying the apple in fall.

Tim Peake's Mission Logo

Tim Peake’s Mission Logo

All of this is well and good but it leads automatically to the question, is the tale of Isaac and the apple a real story or is it just a myth? The answer is that it is both.

Modern historians of Early Modern science tend to contemptuously dismiss the whole story as a myth. One who vehemently rejects it is Patricia Fara, who is an expert on Newtonian mythology and legend building having researched and written the excellent book, Newton: The Making of Genius[1]. In her Science: A Four Thousand Year History she has the following to say about the apple story[2]:

More than any other scientific myth, Newton’s falling apple promotes the romantic notion that great geniuses make momentous discoveries suddenly and in isolation […] According to simplistic accounts of its [Principia’s] impact, Newton founded modern physics by introducing gravity and simultaneously implementing two major transformations in methodology: unification and mathematization. By drawing a parallel between an apple and the Moon, he linked an everyday event on Earth with the motion of the planets through the heavens, thus eliminating the older, Aristotelian division between the terrestrial and celestial realms.


Although Newton was undoubtedly a brilliant man, eulogies of a lone genius fail to match events. Like all innovators, he depended on the earlier work of Kepler, Galileo, Descartes and countless others […]


The apple story was virtually unknown before Byron’s time. [Fara opens the chapter with a Byron poem hailing Newton’s discovery of gravity by watching the apple fall].

Whilst I would agree with almost everything that Fara says, here I think she is, to quote Kepler, guilty of throwing out the baby with the bath water. But before I explain why I think this let us pass review of the myth that she is, in my opinion, quite rightly rejecting.

The standard simplistic version of the apple story has Newton sitting under the Woolsthorpe Manor apple tree on a balmy summer’s day meditation on mechanics when he observes an apple falling. Usually in this version the apple actually hits him on the head and in an instantaneous flash of genius he discovers the law of gravity.

This is of course, as Fara correctly points out, a complete load of rubbish. We know from Newton’s notebooks and from the draughts of Principia that the path from his first studies of mechanics, both terrestrial and celestial, to the finished published version of his masterpiece was a very long and winding one, with many cul-de-sacs, false turnings and diversions. It involved a long and very steep learning curve and an awful lot of very long, very tedious and very difficult mathematical calculations. To modify a famous cliché the genius of Principia and the theories that it contains was one pro cent inspiration and ninety-nine pro cent perspiration.

If all of this is true why do I accuse Fara of throwing out the baby with the bath water? I do so because although the simplistic story of the apple is a complete myth there really was a story of an apple told by Newton himself and in the real versions, which differ substantially from the myth, there is a core of truth about one step along that long and winding path.

Having quoted Fara I will now turn to, perhaps Newton’s greatest biographer, Richard Westfall. In his Never at Rest, Westfall of course addresses the apple story:

What then is one to make of the story of the apple? It is too well attested to be thrown out of court. In Conduitt’s version one of four independent ones, …

Westfall tells us that the story is in fact from Newton and he told to on at least four different occasions to four different people. The one Westfall quotes is from John Conduitt, who was Newton’s successor at the Royal Mint, married his niece and house keeper Catherine Barton and together with her provided Newton with care in his last years. The other versions are from the physician and antiquarian William Stukeley, who like Newton was from Lincolnshire and became his friend in the last decade of Newton’s life, the Huguenot mathematician Abraham DeMoivre, a convinced Newtonian and Robert Greene who had the story from Martin Folkes, vice-president of the Royal Society whilst Newton was president. There is also an account from Newton’s successor as Lucasian professor, William Whiston, that may or may not be independent. The account published by Newton’s first published biographer, Henry Pemberton, is definitely dependent on the accounts of DeMoivre and Whiston. The most well known account is that of Voltaire, which he published in his Letters Concerning the English Nation, London 1733 (Lettres philosophiques sur les Anglais, Rouen, 1734), and which he says he heard from Catherine Conduitt née Barton. As you can see there are a substantial number of sources for the story although DeMoivre’s account, which is very similar to Conduitt’s doesn’t actually mention the apple, so as Westfall says to dismiss it out of hand is being somewhat cavalier, as a historian.

To be fair to Fara she does quote Stukeley’s version before the dismissal that I quoted above, so why does she still dismiss the story. She doesn’t, she dismisses the myth, which has little in common with the story as related by the witnesses listed above. Before repeating the Conduitt version as quoted by Westfall we need a bit of background.

In 1666 Isaac, still an undergraduate, had, together with all his fellow students, been sent down from Cambridge because of an outbreak of the plague. He spent the time living in his mother’s house, the manor house in Woolsthorpe, teaching himself the basics of the modern terrestrial mechanics from the works of Descartes, Huygens and the Salisbury English translation of Galileo’s Dialogo. Although he came nowhere near the edifice that was the Principia, he did make quite remarkable progress for a self-taught twenty-four year old. It was at this point in his life that the incident with the apple took place. We can now consider Conduitt’s account:

In the year 1666 he retired again from Cambridge … to his mother in Lincolnshire & whilst he was musing in a garden it came to his thought that the power of gravity (wch brought an apple from the tree to the ground) was not limited to a certain distance from the earth but that this power must extend much further than was normally thought. Why not as high as the moon said he to himself & if so that must influence her motion & and perhaps retain her in her orbit, where-upon he fell to calculating what would be the effect of this supposition but being absent from books & taking common estimate in use among Geographers & our seamen before Norwood had measured the earth, that 60 English miles were contained in one degree latitude on the surface of the Earth his computation did not agree with his theory & inclined him to entertain a notion that together with the force of gravity there might be a mixture of that force wch the moon would have if it was carried along in a vortex…[3]

As you can see the account presented here by Conduitt differs quite substantially from the myth. No tree, no apple on the head, no instantaneous discovery of the theory of gravity. What we have here is a young man who had been intensely studying the theory of forces, in particular forces acting on a body moving in a circle, applying what he had learnt to an everyday situation the falling apple and asking himself if those forces would also be applicable to the moon. What is of note here is the fact that his supposition didn’t work out. Based on the data he was using, which was inaccurate, his calculations showed that the forces acting on the apple and those acting on the moon where not the same! An interesting thought but it didn’t work out. Oh well, back to the drawing board. Also of note here is the reference to a vortex, revealing Newton to be a convinced Cartesian. By the time he finally wrote the Principia twenty years later he had turned against Descartes and in fact Book II of Principia is devoted to demolishing Descartes’ vortex theory.

In 1666 Newton dropped his study of mechanics for the meantime and moved onto optics, where his endeavours would prove more fruitful, leading to his discoveries on the nature of light and eventually to his first publication in 1672, as well as the construction of his reflecting telescope.

The Newtonian Reflector Source: Wikimedia Commons

The Newtonian Reflector
Source: Wikimedia Commons

Over the next two decades Newton developed and extended his knowledge of mechanics, whilst also developing his mathematical skills so that when Halley came calling in 1684 to ask what form a planetary orbit would take under an inverse squared law of gravity, Newton was now in a position to give the correct answer. At Halley’s instigation Newton now turned that knowledge into a book, his Principia, which only took him the best part of three years to write! As can be seen even with this briefest of outlines there was definitely nothing instantaneous or miraculous about the creation of Newton’ masterpiece.

So have we said all that needs to be said about Newton and his apple, both the story and the myth? Well no. There still remains another objection that has been raised by historians, who would definitely like to chuck the baby out with the bath water. Although there are, as noted above, multiple sources for the apple-story all of them date from the last decade of Newton’s life, fifty years after the event. There is a strong suspicion that Newton, who was know to be intensely jealous of his priorities in all of his inventions and discoveries, made up the apple story to establish beyond all doubt that he and he alone deserved the credit for the discovery of universal gravitation. This suspicion cannot be simply dismissed as Newton has form in such falsification of his own history. As I have blogged on an earlier occasion, he definitely lied about having created Principia using the, from himself newly invented, calculus translating it back into conventional Euclidian geometry for publication. We will probably never know the final truth about the apple-story but I for one find it totally plausible and am prepared to give Isaac the benefit of the doubt and to say he really did take a step along the road to his theory of universal gravitation one summer afternoon in Woolsthorpe in the Year of Our Lord 1666.

[1] Patricia Fara, Newton: The Making of Genius, Columbia University Press, 2002

[2] Patricia Fara, Science: A Four Thousand Year History, ppb. OUP, 2010, pp. 164-165

[3] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, ppb. CUP, 1980 p. 154


Filed under History of Astronomy, History of Mathematics, History of Optics, History of Physics, History of science, Myths of Science, Newton

The Astrolabe – an object of desire

Without doubt the astrolabes is one of the most fascinating of all historical astronomical instruments.

Astrolabe Renners Arsenius 1569 Source: Wikimedia Commons

Astrolabe Renners Arsenius 1569
Source: Wikimedia Commons

To begin with it is not simply one object, it is many objects in one:


  • An astronomical measuring device
  • A timepiece
  • An analogue computer
  • A two dimensional representation of the three dimensional celestial sphere
  • A work of art and a status symbol


This Medieval-Renaissance Swiss Army penknife of an astronomical instrument had according to one medieval Islamic commentator, al-Sufi writing in the tenth century, more than one thousand different functions. Even Chaucer in what is considered to be the first English language description of the astrolabe and its function, a pamphlet written for a child, describes at least forty different functions.

The astrolabe was according to legend invented by Hipparchus of Nicaea, the second century BCE Greek astronomer but there is no direct evidence that he did so. The oldest surviving description of the planisphere, that two-dimensional representation of the three-dimensional celestial sphere, comes from Ptolemaeus in the second century CE.

Modern Planisphere Star Chart c. 1900 Source: Wikimedia Commons

Modern Planisphere Star Chart c. 1900
Source: Wikimedia Commons

Theon of Alexandria wrote a thesis on the astrolabe, in the fourth century CE, which did not survive and there are dubious second-hand reports that Hypatia, his daughter invented the instrument. The oldest surviving account of the astrolabe was written in the sixth century CE by John Philoponus. However it was first the Islamic astronomers who created the instrument, as it is known today, it is said for religious purposes, to determine the direction of Mecca and the time of prayer. The earliest surviving dated instrument is dated 315 AH, which is 927/28 CE.

The Earliest  Dated Astrolabe Source: See Link

The Earliest Dated Astrolabe
Source: See Link

It is from the Islamic Empire that knowledge of the instrument found its way into medieval Europe. Chaucer’s account of it is based on that of the eight-century CE Persian Jewish astrologer, Masha’allah ibn Atharī, one of whom claim to fame is writing the horoscope to determine the most auspicious date to found the city of Baghdad.

So-called Chaucer Astrolabe dated 1326, similar to the one Chaucer describes, British Museum Source: Wikimedia Commons

So-called Chaucer Astrolabe dated 1326, similar to the one Chaucer describes, British Museum
Source: Wikimedia Commons

However this brief post is not about the astrolabe as a scientific instrument in itself but rather the last point in my brief list above the astrolabe as a work of art and a status symbol. One of the reasons for people’s interest in astrolabes is the fact that they are simply beautiful to look at. This is not a cold, functional scientific instrument but an object to admire, to cherish and desire. A not uncommon reaction of people being introduced to astrolabes for the first time is, oh that is beautiful; I would love to own one of those. And so you can there are people who make replica astrolabes but buying one will set you back a very pretty penny.

That astrolabes are expensive is not, however, a modern phenomenon. Hand crafted brass, aesthetically beautiful, precision instruments, they were always very expensive and the principal market would always have been the rich, often the patrons of the instrument makers. The costs of astrolabes were probably even beyond the means of most of the astronomers who would have used them professionally and it is significant that most of the well know astrolabe makers were themselves significant practicing astronomers; according to the principle, if you need it and can’t afford it then make it yourself. Other astronomers would probably have relied on their employers/patrons to supply the readies. With these thoughts in mind it is worth considering the claim made by David King, one of the world’s greatest experts on the astrolabe, that the vast majority of the surviving astrolabes, made between the tenth nineteenth centuries – about nine hundred – were almost certainly never actually used as scientific instruments but were merely owned as status symbols. This claim is based on, amongst other things, the fact that they display none of the signs of the wear and tear, which one would expect from regular usage.

Does this mean that the procession of astrolabes was restricted to a rich elite and their employees? Yes and no. When European sailors began to slowly extend their journeys away from coastal waters into the deep sea, in the High Middle Ages they also began to determine latitude as an element of their navigation. For this purpose they needed an instrument like the astrolabe to measure the elevation of the sun or of chosen stars. The astrolabe was too complex and too expensive for this task and so the so-called mariners astrolabe was developed, a stripped down, simplified, cheaper and more robust version of the astrolabe. When and where the first mariner’s astrolabe was used in not known but probably not earlier than the thirteenth century CE. Although certainly not cheap, the mariner’s astrolabe was without doubt to be had for considerably less money than its nobler cousin.


Mariner’s Astrolabe Francisco de Goes 1608 Source: Istituto e Museo di Storia della Scienza, Firenze

Another development came with the advent of printing in the fifteenth century, the paper astrolabe. At first glance this statement might seem absurd, how could one possibly make a high precision scientific measuring instrument out of something, as flexible, unstable and weak as paper? The various parts of the astrolabe, the planisphere, the scales, the rete star-map, etc. are printed onto sheets of paper. These are then sold to the customer who cuts them out and pastes them onto wooden forms out of which he then constructs his astrolabe, a cheap but serviceable instrument. One well-known instrument maker who made and sold printed-paper astrolabes and other paper instruments was the Nürnberger mathematician and astronomer Georg Hartmann. The survival rate of such cheap instruments is naturally very low but we do actually have one of Hartmann’s wood and paper astrolabes.

Hartmann Paper Astrolabe Source: Oxford Museum of History of Science

Hartmann Paper Astrolabe
Source: Oxford Museum of History of Science

In this context it is interesting to note that, as far as can be determined, Hartmann was the first instrument maker to develop the serial production of astrolabes. Before Hartmann each astrolabe was an unicum, i.e. a one off instrument. Hartmann standardised the parts of his brass astrolabes and produced them, or had them produced, in batches, assembling the finished product out of these standardised parts. To what extent this might have reduced the cost of the finished article is not known but Hartmann was obviously a very successful astrolabe maker as nine of those nine hundred surviving astrolabes are from his workshop, probably more than from any other single manufacturer.

Hartmann Serial Production Astrolabe Source: Museum Boerhaave

Hartmann Serial Production Astrolabe
Source: Museum Boerhaave


If this post has awoken your own desire to admire the beauty of the astrolabe then the biggest online collection of Medieval and Renaissance scientific instruments in general and astrolabes in particular is the Epact website, a collaboration between the Museum of the History of Science in Oxford, the British Museum, the Museum of the History of Science in Florence and the Museum Boerhaave in Leiden.

This blog post was partially inspired by science writer Philip Ball with whom I had a brief exchange on Twitter a few days ago, which he initiated, on our mutual desire to possess a brass astrolabe.






Filed under History of Astrology, History of Astronomy, History of science, History of Technology, Mediaeval Science, Renaissance 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