The emergence of modern astronomy – a complex mosaic: Part XXI

A widespread myth in the popular history of astronomy is that Galileo Galilei (1564–1642) was the first or even the only astronomer to realise the potential of the newly invented telescope as an instrument for astronomy. This perception is very far from the truth. He was just one of a group of investigator, who realised the telescopes potential and all of the discoveries traditionally attributed to Galileo were actually made contemporaneously by several people, who full of curiosity pointed their primitive new instruments at the night skies. So why does Galileo usually get all of the credit? Quite simply, he was the first to publish.

Galileo’s “cannocchiali” telescopes at the Museo Galileo, Florence

Starting in the middle of 1609 various astronomers began pointing primitive Dutch telescopes at the night skies, Thomas Harriot (1560–1621) and his friend and student William Lower (1570–1615) in Britain, Simon Marius (1573–1625) in Ansbach, Johannes Fabricius (1587–1616) in Frisia, Odo van Maelcote (1572–1615) and Giovanni Paolo Lembo (1570–1618) in Rome, Christoph Scheiner (1573 or 1575–1650) in Ingolstadt and of course Galileo in Padua. As far as we can ascertain Thomas Harriot was the first and the order in which the others took up the chase is almost impossible to determine and also irrelevant, as it was who was first to publish that really matters and that was, as already stated, Galileo.

Harriot made a simple two-dimensional telescopic sketch of the moon in the middle of 1609.

Thomas Harriot’s initial telescopic sketch of the moon from 1609 Source: Wikimedia Commons

Both Galileo and Simon Marius started making telescopic astronomical observations sometime late in the same year. At the beginning Galileo wrote his observation logbook in his Tuscan dialect and then on 7 January 1610 he made the discovery that would make him famous, his first observation of three of the four so-called Galilean moons of Jupiter.

It was on this page that Galileo first noted an observation of the moons of Jupiter. This observation upset the notion that all celestial bodies must revolve around the Earth. Source: Wikimedia Commons

Galileo realised at once that he had hit the jackpot and immediately changed to writing his observations in Latin in preparation for a publication. Simon Marius, who made the same discovery just one day later, didn’t make any preparations for immediate publication. Galileo kept on making his observations and collecting material for his publication and then on 12 March 1610, just two months after he first saw the Jupiter moons, his Sidereus Nuncius (Starry Messenger of Starry Message, the original Latin is ambiguous) was published in Padua but dedicated to Cosimo II de Medici, Fourth Grand Duke of Tuscany. Galileo had already negotiated with the court in Florence about the naming of the moons; he named them the Medicean Stars thus taking his first step in turning his discovery into personal advancement.

Title page of Sidereus nuncius, 1610, by Galileo Galilei (1564-1642). *IC6.G1333.610s, Houghton Library, Harvard University Source: Wikimedia Commons

What exactly did Galileo discover with his telescope, who else made the same discoveries and what effect did they have on the ongoing astronomical/cosmological debate? We can start by stating quite categorically that the initial discoveries that Galileo published in his Sidereus Nuncius neither proved the heliocentric hypothesis nor did they refute the geocentric one,

The first discovery that the Sidereus Nuncius contains is that viewed through the telescope many more stars are visible than to the naked-eye. This was already known to those, who took part in Lipperhey’s first ever public demonstration of the telescope in Den Haag in September 1608 and to all, who subsequently pointed a telescope of any sort at the night sky. This played absolutely no role in the astronomical/cosmological debate but was worrying for the theologians. Christianity in general had accepted both astronomy and astrology, as long as the latter was not interpreted deterministically, because the Bible says  “And God said, Let there be lights in the firmament of the heaven to divide the day from night; and let them be for signs, and for seasons, and for days, and years:” (Gen 1:14). If the lights in the heavens are signs from God to be interpreted by humanity, what use are signs that can only be seen with a telescope?

Next up we have the fact that some of the nebulae, indistinct clouds of light in the heavens, when viewed with a telescope resolved into dense groups of stars. Nebulae had never played a major role in Western astronomy, so this discovery whilst interesting did not play a major role in the contemporary debate. Simon Marius made the first telescopic observations of the Andromeda nebula, which was unknown to Ptolemaeus, but which had already been described by the Persian astronomer, Abd al-Rahman al-Sufi (903–986), usually referred to simply as Al Sufi. It is historically interesting because the Andromeda nebula was the first galaxy to be recognised outside of the Milky Way.

Al Sufi’s drawing of the constellation Fish with the Andromeda nebula in fount of it mouth

Galileo’s next discovery was that the moon was not smooth and perfect, as required of all celestial bodies by Aristotelian cosmology, but had geological feature, mountains and valleys, just like the earth i.e. the surface was three-dimensional and not two-dimensional, as Harriot had sketched it. This perception of Galileo’s is attributed to the fact that he was a trained painter used to creating light and shadows in paintings and he thus recognised that what he was seeing on the moons surface was indeed shadows cast by mountains.

As soon as he read the Sidereus Nuncius, Harriot recognised that Galileo was correct and he went on to produce the first real telescopic map of the moon.

Thomas Harriot’s 1611 telescopic map of the moon Source: Wikimedia Commons

Galileo’s own washes of the moon, the most famous illustrations in the Sidereus Nuncius, are in fact studies to illustrate his arguments and not accurate illustrations of what he saw.

Galileo’s sketches of the Moon from Sidereus Nuncius. Source: Wikimedia Commons

That the moon was earth like and for some that the well-known markings on the moon, the man in the moon etc., are in fact a mountainous landscape was a view held by various in antiquity, such as Thales, Orpheus, Anaxagoras, Democritus, Pythagoras, Philolaus, Plutarch and Lucian. In particular Plutarch (c. 46–c. 120 CE) in his On the Face of the Moon in his Moralia, having dismissed other theories including Aristotle’s wrote:

Just as our earth contains gulfs that are deep and extensive, one here pouring in towards us through the Pillars of Herakles and outside the Caspian and the Red Sea with its gulfs, so those features are depths and hollows of the Moon. The largest of them is called “Hecate’s Recess,” where the souls suffer and extract penalties for whatever they have endured or committed after having already become spirits; and the two long ones are called “the Gates,” for through them pass the souls now to the side of the Moon that faces heaven and now back to the side that faces Earth. The side of the Moon towards heaven is named “Elysian plain,” the hither side, “House of counter-terrestrial Persephone.”

So Galileo’s discovery was not so sensational, as it is often presented. However, the earth-like, and not smooth and perfect, appearance of the moon was yet another hole torn in the fabric of Aristotelian cosmology.

Of course the major sensation in the Sidereus Nuncius was the discovery of the four largest moons of Jupiter.

Galileo’s drawings of Jupiter and its Medicean Stars from Sidereus Nuncius. Image courtesy of the History of Science Collections, University of Oklahoma Libraries. Source: Wikimedia Commons

This contradicted the major premise of Aristotelian cosmology that all of the celestial bodies revolved around a common centre, his homo-centricity.  It also added a small modicum of support to a heliocentric cosmology, which had suffered from the criticism, if all the celestial bodies revolve around the sun, why does the moon continue to revolve around the earth. Now Jupiter had not just one but four moons, or satellites as Johannes Kepler called them, so the earth was no longer alone in having a moon. As already stated above Simon Marius discovered the moons of Jupiter just one day later than Galileo but he didn’t publish his discovery until 1614. A delay that would later bring him a charge of plagiarism from Galileo and ruin his reputation, which was first restored at the end of the nineteenth century when an investigation of the respective observation data showed that Marius’ observations were independent of those of Galileo.

The publication of the Sidereus Nuncius was an absolute sensation and the book quickly sold out. Galileo went, almost literally overnight, from being a virtually unknown, middle aged, Northern Italian, professor of mathematics to the most celebrated astronomer in the whole of Europe. However, not everybody celebrated or accepted the truth of his discoveries and that not without reason. Firstly, any new scientific discovery needs to be confirmed independently by other. If Simon Marius had also published early in 1610 things might have been different but he, for whatever reasons, didn’t publish his Mundus Jovialis (The World of Jupiter) until 1614. Secondly there was no scientific explanation available that explained how a telescope functioned, so how did anyone know that what Galileo and others were observing was real? Thirdly, and this is a very important point that often gets ignored, the early telescopes were very, very poor quality suffering from all sorts of imperfections and distortions and it is almost a miracle that Galileo et al discovered anything with these extremely primitive instruments.

As I stated in the last episode, the second problem was solved by Johannes Kepler in 1611 with the publication of his Dioptrice.

A book that Galileo, always rather arrogant, dismissed as unreadable. This was his triumph and nobody else was going to muscle in on his glory. The third problem was one that only time and improvements in both glass making and the grinding and polishing of lenses would solve. In the intervening years there were numerous cases of new astronomical discoveries that turned out to be artefacts produced by poor quality instruments.

The first problem was the major hurdle that Galileo had to take if he wanted his discoveries to be taken seriously. Upon hearing of Galileo discoveries, Johannes Kepler in Prague immediately put pen to paper and fired off a pamphlet, Dissertatio cum Nuncio Sidereo (Conversation with the Starry Messenger) congratulating Galileo, welcoming his discoveries and stating his belief in their correctness, which he sent off to Italy. Galileo immediately printed and distributed a pirate copy of Kepler’s work, without even bothering to ask permission, it was after all a confirmation from the Imperial Mathematicus and Kepler’s reputation at this time was considerably bigger than Galileo’s.

A reprint of Kepler’s letter to Galileo, originally issued in Prague in 1610

However, Kepler’s confirmations were based on faith and not personal confirmatory observations, so they didn’t really solve Galileo’s central problem. Help came in the end from the Jesuit astronomers of the Collegio Romano.

Odo van Maelcote and Giovanni Paolo Lembo had already been making telescopic astronomical observations before the publication of Galileo’s Sidereus Nuncius. Galileo also enjoyed good relations with Christoph Clavius (1538–1612), the founder and head of the school of mathematics at the Collegio Romano, who had been instrumental in helping Galileo to obtain the professorship in Padua. Under the direction of Christoph Grienberger (1561–1636), soon to be Clavius’ successor as professor for mathematics at the Collegio, the Jesuit astronomers set about trying to confirm all of Galileo’s discoveries. This proved more than somewhat difficult, as they were unable, even with Galileo’s assistance via correspondence, to produce an instrument of sufficient quality to observe the moons of Jupiter. In the end Antonio Santini (1577–1662), a mathematician from Venice, succeeded in producing a telescope of sufficient quality for the task, confirmed for himself the existence of the Jupiter moons and then sent a telescope to the Collegio Romano, where the Jesuit astronomers were now also able to confirm all of Galileo’s discovery. Galileo could not have wished for a better confirmation of his efforts, nobody was going to doubt the word of the Jesuits.

In March 1611 Galileo travelled to Rome, where the Jesuits staged a banquet in his honour at which Odo van Maelcote held an oration to the Tuscan astronomer. Galileo’s strategy of dedicating the Sidereus Nuncius to Cosimo de Medici and naming the four moons the Medicean Stars paid off and he was appointed court mathematicus and philosophicus in Florence and professor of mathematics at the university without any teaching obligations; Galileo had arrived at the top of the greasy pole but what goes up must, as we will see, come down.

 

 

 

 

The emergence of modern astronomy – a complex mosaic: Part XI

Despite the high level of anticipation De revolutionibus cannot be in anyway described as hitting the streets running; it was more a case of dribbling out very slowly into the public awareness. There are several reasons for this. Today there is a well-oiled machine, which goes into operations when an important new book is published. Book reviews and adverts in the relevant journals and newspapers, books delivered in advance to bookshops all over the country, radio and television interviews with the author and so on.

Absolutely none of this apparatus existed in anyway in the fifteenth century. There were no journals or newspapers, where reviews and adverts could be published. Information about a new publication was distributed over the academic grapevine by mail; the grapevine was quite efficient with scholars communicating with each other throughout Europe but the mail system wasn’t. Letters often took months and quite often never arrived at all. There were no bookstores, as we know them today and no book distribution network. Petreius had a stall on the local market place but he probably would not have sold many copies of De revolutionibus in Nürnberg itself.

A 19th century painting of the Nürnberg market place

In this context it is interesting that the town library doesn’t own a copy of the 1^st edition. For other sales, other than by mail, Petreius would have transported copies of the book packed into barrels to the annual fairs in Leipzig and Frankfurt, where, as well as private customers, other printer publishers would buy copies of the book to take back to their home towns to supplement their own production for their local customers. The Leipzig fair took place at Easter and in autumn, the Frankfurt fair only in autumn. Easter 1543 was in April so the distribution of De revolutionibus only really began in the autumn of that year.

Frankfurt Book Fair 1500

The next factors that slowed the reception of De revolutionibus were the price and the content. As a large book with a complex mathematical content with lots of tables and diagrams, De revolutionibus was a very expensive book putting it outside of the financial range of students or anybody without a substantial income or private fortune. A first edition bought by the astrologer Valentin Engelhart (1516-1562) in 1545 cost 1 florin = 12 groschen. A students university matriculation fees at this time cost between 6 and 10 groschens. It is indicative that Kepler could only afford to acquire a second hand copy. Owen Gingerich speculates that the high cost of the book is the reason for the comparatively high survival of copies, Gingerich estimates about fifty per cent. It was very expensive so people took good care of it. The high price and the complex contents very much limited potential sales.

De Revolutionibus woodcut of the heliocentric cosmos Source: Latin Wikisource

In terms of content this was a major, heavy duty, large-scale mathematical text and not in anyway something for the casual reader, no mater how well read. Copernicus’ Mathemata mathematicis scribuntur was meant very seriously. This suggests that the potential circle of purchasers was fairly strictly limited to the comparatively small group of mathematical astronomers, who would be capable of reading and understanding Copernicus’ masterpiece. Given his record in the field of mathematical and astronomical/astrological publishing Petreius naturally already had a group of customers to whom he could offer his latest coup in this genre, otherwise he probably would not have published De revolutionibus. However, even if he could get this very specialist book to its specialist group of readers, they would require a comparatively long time to read, work through and digest its complex contents. The earliest known published reaction to De revolutionibus was Gemma Frisius’ De radio astronomico et geometrico a booklet of a multipurpose astronomical and geometrical instrument published in 1545 two years after Copernicus’ volume.

De radio astronomico et geometrico 

Here at this comparatively early point Frisius, who knew of Copernicus’ hypothesis through the Narratio Prima and and had been invited by Dantiscus, Prince-Bishop of Frombork, one of his patrons, to come to Frombork and work with Copernicus, displays a very cautious attitude towards the new heliocentric astronomy although he is very critical towards Ptolemaeus’ work.

Johannes Dantiscus Source: Wikimedia Commons

Given that the main purpose of astronomy was, at this time, still to provide astronomical data for astrology, navigation and cartography many of those potentially interested in the new astronomy were waiting for new planetary tables and ephemerides before passing judgement. The earliest planetary tables, the Tabulae prutenicae (Prutenic Tables) based on De revolutionibus, but not exclusively, were produced by the professor for the higher mathematics (music and astronomy) at Wittenberg Erasmus Reinhold (1511–1553) and first published in 1551.

Source: Wikimedia Commons

These tables were financed by Albrecht I, Duke of Prussia hence the name Prutenic i.e. Prussia.

Albrecht, Duke of Prussia portrait by Lucas Cranach the elder Source: Wikimedia Commons

Interestingly Reinhold was not a supporter of heliocentricity. Ephemerides based on the Prutenic Tables were produced in the Netherlands by Johannes Stadius (1527–1579) a pupil of Gemma Frisius in 1554 with an introductory letter by his old teacher.

Johannes Stadius Source: Wikimedia Commons

A second set of ephemerides, also based on the Prutenic Tables, were produced in England by John Feild (c. 1525–1587), a pupil of John Dee (1527–1608) in 1557. Dee was another pupil of Gemma Frisius, so this might be a case of the academic grapevine in operation. These tables and ephemerides played an important roll in spreading awareness of the new heliocentric hypothesis.

Whereas with a modern publication reception will probably be judged in terms of months or even weeks for a popular book and a few years for a serious academic title; looking at De revolutionibus to judge its reception we really need to cover the sixty plus years following its publication up to the invention of the telescope, the next major game changer in astronomy.

There is a popular misconception that that reception can be quantified in terms of those for and those against the heliocentric hypothesis. This is very much not the case. As I tried to make clear at the beginning of this series the sixteenth century was very much characterised by very lively debates on various aspects of astronomy–the nature, status and significance of comet, a lively revival of the Aristotelian homocentric spheres model of the cosmos and a growing dissatisfaction with the quality of the available astronomical data. There were small smouldering fires of debate everywhere within the European astronomical community, Copernicus’ De revolutionibus turned them into a raging bush fire; the reactions to its publication were multifaceted and the suggested changes it provoked were wide-ranging and highly diverse. It would be more than a hundred years before the smoke cleared and a general consensus could be found within the astronomical community.

 

 

 

 

 

 

The emergence of modern astronomy – a complex mosaic: Part IX

In 1542 the manuscript of De revolutionibus arrived at Petreius’ printing office in Nürnberg followed by Rheticus who intended to see it through the press. I argued in Part VII that Johannes Petreius had in fact commissioned Rheticus to see if Copernicus had written anything substantial on his astronomical theories and if so to persuade him to allow Petreius to publish it. Petreius’ printing office was certainly the right address for the publication of a major new work on astronomy, as he was certainly the leading scientific publisher–astrology, astronomy, mathematics–in the Holy Roman Empire of German States and probably the whole of Europe but who was Johannes Petreius?

The Petreius printing office in Nürnberg Photo by the author

He was born Hans Peter, whereby Peter is the family name, into a family of wealthy farmers in the Lower Franconia village of Langendorf near Hammelburg in 1496 or 1497. He matriculated at the university of Basel in 1512, graduating BA in 1515 and MA in 1517. He next appears as a witness in a court case in Basel in 1519, where he is described, as working as a proofreader for the Basler printer publisher Adam Petri. This explains why he had chosen to study in Basel, as Adam Petri was his uncle. Petri is the Swizz German version of the name Peter. Presumably, having learnt the black art, as printing was known, from his uncle he moved to Nürnberg in 1523 and set up his own printing office. The was almost certainly an attempt by the Peter family to cash in on the gradual collapse of the Koberger printing office following the death of Aton Koberger in 1513. The Petri-Froben-Amerbach printing cooperative had been Koberger’s licensees in Basel, printing his titles on commission.

Source: Wikimedia Commons

Hans Peter now sporting the Latinised name, Johannes Petreius, succeeded in establishing himself against the local competition and by 1535 was the leading printer publisher in Nürnberg. Like most other printer publishers Petreius’ main stock in trade was printing religious volumes but in the 1530s he began to specialise in printing scientific texts. Exactly why he chose to follow this business path is not known but it was probably the ready availability of the large number of mathematical, astrological and astronomical manuscripts brought to Nürnberg by Regiomontanus when he set up his own printing office in 1471. This hypothesis is supported by the fact that several of Petreius’ earliest scientific publications were all of manuscripts from this collection, all of which were edited for publication by Johannes Schöner, who would later be the addressee of Rheticus’ Narratio  Prima.

This series of publications started with Schöner’s edition of Regiomontanus’ own De Triangulis in 1533, a very important work in the history of trigonometry. This was also one of the volumes that Rheticus took with him to Frombork, as a present for Copernicus.

Source:

Schöner followed this with Regiomontanus’ Tabulae astronomicaein 1536. Petreius’ activities in the area were not however restricted to Schöner’s output. Earlier he published the first Greek edition of Ptolemaeus’ Tetrabiblos, under the title Astrologica, edited by Joachim Camerarius (1500–1574), which included Camerarius’ translation into Latin of Books I & II and partial translations of Books III & IV together with his notes on Books I & II and the Greek text of the Centiloquium, a collection of one hundred astrological aphorism falsely attributed to Ptolemaeus, with a Latin translation by Giovanni Pontano (1426–1503).

Opening chapter of the first printed edition of Ptolemy’s Tetrabiblos, transcribed into Greek and Latin by Joachim Camerarius (Nuremberg, 1535). Source: Wikimedia Commons

A year earlier Petreius had published Johann Carion’s Practica new – auffs 1532 mit einer auslegung des gesehen cometen. Through these publications it is clear that the principle interest is in astrology and it is here that money was to be made. Over the next twenty plus years Petreius published more texts from Regiomontanus edited by Schöner, some of Schöner’s own works on astronomy and cartography, reckoning and algebra books from Christoph Rudolff  (c. 1500–before 1543) and Michael Stifel (1487–1567). Various scientific texts edited by Peter Apian including his and Georg Tannstetter’s edition of Witelo’s Perspectiva (1535), another of the volumes that Rheticus took with him to Frombork for Copernicus. Various Arabic astrological texts, the Tractatus astrologicae (1540) of Lucas Gauricus (1575–1558), who along with Schöner and Cardano was one of the most important astrologers of the first half of the sixteenth century. Petreius became the publisher of Gerolamo Cardano (1501–1576) north of the Alps, publishing his works on mathematics, astronomy, medicine, astrology and philosophy, all of which were highly successful.

Source: Wikimedia Commons

He also published alchemical works from Abū Muḥammad Jābir ibn Aflaḥ better known in the West as Geber. As well as all this, Petreius commissioned and published the first German translation of Vitruvius’ De architectura, a bible for Renaissance artist-engineers.

Petreius’ scientific catalogue was very wide but also had depth, including as it did various classics by Regiomontanus, Schöner, Stifel, Cardano and Witelo. If anybody could adequately present Copernicus’ masterpiece to the world then it was Johannes Petreius.

Rheticus had originally intended seeing Copernicus’ manuscript through the press but Philipp Melanchthon had other plans for his errant protégée. In the meantime Rheticus had, at the request of Joachim Camerarius, who was now rector of the University of Leipzig and had obviously been impressed by Rheticus during their meeting in Tübingen, been offered a chair in mathematics at Leipzig.

Joachim Camerarius, 18th-century engraving by Johann Jacob Haid. Source: Wikimedia Commons

In the autumn of 1542 Rheticus, under pressure from Melanchthon, left Nürnberg and preceded to Leipzig, where he was appointed professor of higher mathematics i.e. astronomy and music and his direct involvement in De revolutionibus came to an end. Petreius still needed an editor to see Copernicus’ weighty tome through the press and this duty was taken over, with serious consequences by Nürnberg’s Lutheran Protestant preacher, Andreas Osiander (1496 or 1498–1552).

Andreas Osiander portrait by Georg Pencz Source: Wikimedia Commons

Osiander was born in the small town of Gunzenhausen to the south of Nürnberg, the son of Endres Osiander a smith and Anna Herzog. His father was also a local councillor who later became mayor. He matriculated at the University of Ingolstadt in 1515 where he, amongst other things, studied Hebrew under the great humanist scholar and great uncle of Melanchthon, Johannes Reuchlin. In 1520 he was ordained a priest and called to Nürnberg to teach Hebrew at the Augustinian Cloister, a hot bed of reformatory debate, where he also became a reformer. In 1522 he as appointed preacher at the St Lorenz church and became a leading voice for religious reform. Osiander achieved much influence and power in Nürnberg when the city-state became the very first Lutheran Protestant state.

Osiander first became involved with Petreius when the latter started publishing his religious polemics. Petreius also published numerous religious works by both Luther and Melanchthon. Where or how Osiander developed his interest and facility in the mathematical sciences is simply not know but they are attested to by Cardano in the preface to one of his books published by Petreius. In fact it was Osiander, who was responsible for the correspondence between Cardano and the Petreius printing office and he edited Cardano’s books there. When or how Osiander became an editor for Petreius is also not known. In his capacity as editor of De revolutionibus Osiander committed what many have as one of the greatest intellectual crimes in the history of science, he added the infamous ad lectorum, an address to the reader with which the book opens.

Latin Wikisource

The ad lectorum is an essay that it pays to read in full but here we will just consider the salient points, Osiander writes:

There have already been widespread reports about the new novel hypothesis of this work, which declares that the earth moves whereas the sun is at rest in the centre of the universe.

Here Osiander lets us know that knowledge of Copernicus’ heliocentric hypothesis was already widespread–spread by the Commentariolus, the Narratio Prima and by rumour–indicating that there was going to be a high level of expectancy to learn the mathematical details of the system. He goes on:

Hence certain scholars, I have no doubt, are deeply offended and believe that the liberal arts, which were established long ago on a sound basis, should not be thrown in confusion.

Anticipating criticism from conservative circles Osiander goes into defensive mode:

But if these men are willing to examine the matter closely, they will find that the author has done nothing that is blameworthy. For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study. Then he must conceive and devise the causes of these motions or hypotheses about them. Since he cannot in any way attain to the true causes, he will adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry for the future as well as the past.

Here we have the crux of Osiander’s defence. Astronomers are here to produce geometrical models in order to provide accurate predictions of celestial motions and not to determine the unobtainable true causes of those motions. This argument has been dubbed instrumentalist and some hail Osiander as the first instrumentalist philosopher of science. Instrumentalism is a metaphysical attitude to scientific theories that enjoyed a lot of popularity in modern physics in the twentieth century; it doesn’t matter if the models we use describe reality, all that matters in that they predict the correct numerical results. Osiander expands on this viewpoint:

For these hypotheses need not be true or even probable. On the contrary, if they provide a calculus consistent with the observations, that alone is enough.

Here we have the core of why the ad lectorum caused so much outrage over the centuries. Osiander is stating very clearly that the mathematical models of astronomers are useful for predictive purposes but not for describing reality. A view that was fairly commonplace over the centuries amongst those concerned with the subject. Copernicus, however, very clearly deviates from the norm in De revolutionibus in that he presents his heliocentric system as a real model of the cosmos. Osiander’s ad lectorum stands in clear contradiction to Copernicus’ intentions. Osiander then goes into more detail illustrating his standpoint before closing his argument as follows:

…the astronomer will take as his first choice that hypothesis which is easiest to grasp. The philosopher will perhaps rather seek the semblance of the truth. But neither of them will understand or state anything certain, unless it has been divinely revealed to him.

Here we have Osiander restating the standard scholastic division of responsibilities, astronomers provide mathematical models to deliver accurate predictions of celestial motions for use by others, philosophers attempt to provide explanatory models of those motions but truth can only be delivered by divine revelation. The modern astronomy, whose gradual emergence we are tracing had to break down this division of responsibilities in order to become accepted as we shall see in later episodes. Osiander closes with a friendly appeal to the reader to permit the new hypotheses but not to take them too seriously, and thereby make a fool of himself.

Therefore alongside the ancient hypotheses, which are no more probable, let us permit these new hypotheses also the become known, especially since they are admirable as well as simple and bring with them a huge treasure of very skilful observations. So far as hypotheses are concerned, let no one expect anything certain from astronomy, which cannot furnish it, lest he accept as the truth ideas conceived for another purpose, and depart from this study a greater fool than he entered it. Farewell.

There is a widespread belief that Osiander somehow smuggled his ad lectorum into De revolutionibus without the knowledge of either Copernicus or Petreius but the historical evidence speaks against this. There are surviving fragments of a correspondence between Osiander and Copernicus that make it clear that Osiander discussed the stratagem of presenting De revolutionibus as a hypothesis rather that fact with him; although we don’t know how or even if Copernicus reacted to this suggestion. More telling is the situation between Petreius and Osiander.

There is absolutely no way that Osiander could have added the ad lectorum without Petreius’ knowledge. This is supported by subsequent events. When the book appeared Tiedemann Giese was outraged by the presence of the ad lectorum and wrote a letter to the city council of Nürnberg demanding that it be removed and the book reissued without this blemish. The council consulted Petreius on the subject and he let them know in no uncertain terms that it was his book and what he put in it was his business and nobody else’s.

Petreius’ reaction illustrates an important point that modern commentators often overlook. Our concept of copyright didn’t exist in the sixteenth century, the rights to a publish work in general lay with the publisher and not the author. This is clearly demonstrated by the fact that when a publication provoked the ire of the authorities, civil or clerical, it was the printer publisher, who first landed before the court and then in goal rather than the author.

The ad lectorum was anonym but any reader, who was paying attention should have realised through the phrasing that Copernicus was not the author. The Nürnberger astronomer and instrument maker Johannes Pratorius (1537–1615), another Wittenberg graduate, wrote in his copy of De revolutionibus that Rheticus, when Pratorius visited him in 1569, had revealed to him that Osiander was the author of the ad lectorum.

Source: Wikimedia Commons

Michael Maestlin’s copy contains the same information also from Rheticus via Peter Apian. Kepler’s second hand copy had this information added by its original owner Hieronymus Schreiber (birth date unknown–1547), yet another Wittenberg graduate, who had received a gift copy signed by Petreius, because he had substituted for Rheticus in Wittenberg during the latter’s time in Frombork. All of this indicates that Osiander’s authorship of the ad lectorem was circulating on the astronomers’ grapevine by 1570 at the latest. It was first put into print, and thus made general public, by Kepler in his Astronomia Nova in 1609.

As with most books in the Early Modern Period there was no publication date for De revolutionibus but it seems to have been finished by 20^thApril 1543, as Rheticus signed a finished copy on this date. According to a legend, put in the world by Tiedemann Giese, Copernicus received his copy, which was placed into his hands, on his dying day the 24^thMay 1543. Owen Gingerich, who is the expert on the subject, estimates that the 1^stedition probably had a print run of about 400 copies, which carried the mathematical details of Copernicus’ hypothesis out into the wide world.

 

 

 

 

 

Renaissance Heavy Metal

One of the most fascinating and spectacularly illustrated Renaissance books on science and technology is De re metallica by Georgius Agricola (1494–1555). Translated into English the author’s name sounds like a figure from a game of happy families, George the farmer. In fact, this is his name in German, Georg Pawer, in modern German Bauer, which means farmer or peasant or the pawn in chess. Agricola was, however, anything but a peasant; he was an extraordinary Renaissance polymath, who is regarded as one of the founders of modern mineralogy and geology.

Georg Bauer was born in Glauchau on 24 March 1494, the second of seven children, to Gregor Bauer (born between 1518 and 1532) a wealthy cloth merchant and dyer. He was initially educated at the Latin school in Zwickau and attended the University of Leipzig, where he studied theology, philosophy and philology from 1514 to 1517. From 1518 to 1522 he worked as deputy director and then as director of schools in Zwickau. In 1520 he published his first book, a Latin grammar. The academic year 1522-23 he worked as a lecturer at the University of Leipzig. From 1523 to 1526 he studied medicine, philosophy and the sciences at various Northern Italian university graduating with a doctorate in medicine. In Venice he worked for a time for the Manutius publishing house on their edition of the works of Galen.

From 1527 to 1533 Agricola worked as town physician in St. Joachimsthal*, today Jáchymov in the Czech Republic. In those days Joachimsthal was a major silver mining area and it is here that Agricola’s interest in mining was ignited.

Silver mining in Joachimsthal (1548) Source: Wikimedia Commons

In 1530 he issued his first book on mining, Bermannus sive de re metallica, published by the Froben publishing house in Basel. It covered the search for metal ores, the mining methods, the legal framework for mining claims, the transport and processing of the ores. Bermannus refers to Lorenz Bermann, an educated miner, who was the principle source of his information. The book contains an introductory letter from Erasmus, who worked as a copyeditor for Froben during his years in Basel.

Source

In 1533 he published a book on Greek and Roman weights and measures, De mensuris et ponderibus libri V, also published Froben in Basel.

From 1533 to his death in 1555 he was town physician in Chemnitz. He was also district historian for the Saxon aristocratic dynasty. From 1546 onwards he was a member of the town council and served as mayor in 1546, 1547, 1551 and 1553. In Chemnitz he also wrote a book on the plague, De peste libri tres, his only medical book,  as ever published by Froben in 1554.

Source: Internet Archive

Having established himself as an expert on mining with the Bermannus, Agricola devoted more than twenty years to studying and writing about all aspects of mining and the production of metals. He wrote and published a series of six books on the subject between 1546 and 1550, all of them published by Froben.

De ortu et causis subterraneorum libri V, Basel 1546

The origin of material within the earth

De natura eorum, quae effluunt ex terra, Basel 1546

The nature of the material extruded out of the earth

De veteribus et novis metallis libri II, Basel 1546

Ore mining in antiquity and in modern times

De natura fossilium libri X, Basel 1546

The nature of fossils whereby fossils means anything found in the earth and is as much a textbook of mineralogy

De animantibus subterraneis liber, Basel 1549

The living underground

De precio metallorum et monetis liber III, 1550

On precious metals and coins

At the same time he devoted twenty years to composing and writing his magnum opus De re metallica, which was published posthumously in 1556 by Froben in Basel, who took six years to print the book due to the large number of very detailed woodcut prints with which the book is illustrated. These illustrations form an incredible visual record of Renaissance industrial activity. They are also an impressive record of late medieval technology. Agricola’s pictures say much more than a thousand words.

De re metallicahas twelve books or as we would say chapters. What distinguishes Agricola’s work from all previous writings on mineralogy and geology is the extent to which they are based on empirical observation rather than philosophical speculation. Naturally this cannot go very far as it would be several hundred years before the chemistry was developed necessary to really analyse mineralogical and geological specimens but Agricola’s work was a major leap forward towards a modern scientific analysis of metal production.

 

Book I: Discusses the industry of mining and ore smelting

Book II: Discusses ancient mines, finding minerals and metals and the divining rod

Book III: Discusses mineral veins and seams and plotting with the compass

Book IV: Discusses the determination of mine boundaries and mine organisation

Book V: Discusses the principles of mining, the metals, ancient mining and mine surveying

Book VI: Discusses mining tools and equipment, hoists and pumps, ventilation and miners’ diseases

Book VII: Discusses assaying ores and metals and the touchstone

Book VIII: Discusses preparing ores for roasting, crushing and washing and recovering gold by mercury

Book IX: Discusses ores and furnaces for smelting copper, iron and mercury and the use of bellows

Book X: Discusses the recovery of precious metals from base metals as well as separating gold and silver by acid

Book XI: Discusses the recovery of silver from copper by liquidation as well as refining copper

Book XII: Discusses salts, solvents, precipitates, bitumen and glass

Agricola’s wonderfully illustrated volume became the standard reference work on metal mining and production for about the next two hundred years. The original Latin edition appeared in Basel in 1556 and was followed by a German translation in 1557, which was in many aspects defective but remained unchanged in two further editions. There were further Latin editions published in 1561, 1621, and 1657 and German ones in 1580, and 1621, with an improved German translation in 1928 and 1953. There was an Italian translation published in 1563.

 

Of peculiar interest is the English translation. This was first published in 1912 in London, the work of American mining engineer Herbert Hoover (1874–1964) and his wife the geologist Lou Henry (1874–1944). A second edition was published in 1950. Hoover is, of course, better know as the 31^stPresident of the USA, who was elected in 1928 and served from 1929–1933.

Herbert Hoover in his 30s while a mining engineer Source: Wikimedia Commons

Lou Henry, circa 1930 Source: Wikimedia Commons

Agricola’s tome also represents an important development in the history of trades and professions. Before De re metallicaknowledge of trades and crafts was past from master to apprentice verbally and kept secret from those outside of guild, often on pain of punishment. Agricola’s book is one of the first to present the methods and secrets of a profession in codified written form for everyone to read, a major change in the tradition of knowledge transfer.

*A trivial but interesting link exists between St. Joachimsthal and the green back. A silver coin was produced in St. Joachimsthal, which was known as the Joachimsthaler. This got shortened in German to thaler, which mutated in Dutch to daalder or daler and from there in English to dollar.

All illustrations from De re metallica are taken from Bern Dibner, Agricola on Metals, Burndy Library, 1958

 

 

 

 

The emergence of modern astronomy – a complex mosaic: Part VIII

We left Georg Joachim Rheticus[1](1514–1574) just setting out on his journey from Feldkirch to Frombork for what would turn out to be one of the most fateful meetings in the history of science. Our wealthy professor of mathematics travelled in style accompanied by a famulus Heinrich Zell (?–1564), a Wittenberg student, who would later have a career as cartographer, astronomer and librarian. What is rarely mentioned in detail is that Rheticus travelled from Feldkirch to Wittenberg, which is where he collected Zell, and then having acquired permission to extend his sabbatical, continued on his way to Frombork. In total this is a journey of more than 1500 kilometres, hard enough even today but a major expedition in the middle of the sixteenth century.

We have no direct account of the initial meeting between the twenty-five year old mathematics professor and the sixty-six year old cathedral canon.

Portrait of Copernicus holding a lily of the valley, published in Nicolaus Reusner’s Icones (1587), based on a sketch by Tobias Stimmer (c. 1570), allegedly based on a self-portrait by Copernicus. Source: Wikimedia Commons

They obviously got on well, as Rheticus ended staying in the area for two and a half years. Shortly after his arrival Rheticus fell ill and Copernicus took him to Löbau, the home of his friend Tiedemann Giese (1480–1550) Bishop of Kulm, to convalesce.

Portrait of Tiedemann Giese by Hans Schenck, Source: Wikimedia Commons

This episode illustrates an important aspect of Rheticus’ visit. Here was a Lutheran Protestant professor of mathematics from the home of Lutheran Protestantism, Wittenberg University visiting a Catholic cathedral canon in the middle of a deeply Catholic area. Despite the fact that this visit took place in the middle of the Reformation and the beginnings of the Counter Reformation Rheticus was always treated as an honoured guest by all those, who received him whether Protestant, Albrecht, Duke of Prussia,

Albrecht, Duke of Prussia portrait by Lucas Cranach the elder Source: Wikimedia Commons

or Catholic, Copernicus, Giese and above all the Prince-Bishop of Frombork, Johannes Danticus (1485–1548), who although strongly anti-Reformation was also an admirer of Philipp Melanchthon (1497–1560), whom he had met personally.

Johannes Dantiscus Source: Wikimedia Commons

This courtesy across the religious divide amongst scholars during this period of European religious turmoil was actually very common and contradicts a popular image of hate, rejection and bigotry on all fronts and at all levels.

We know of Rheticus’ convalescence in Löbau, because he mentions it on the first page of his Narratio Prima (The First Account) the booklet he wrote shortly after his arrival in Frombork and the first published account of Copernicus’ heliocentric system. He explains that because of his illness he has had barely ten weeks to familiarise himself with the manuscript of Copernicus’ magnum opus in order to describe and explain it in the Narratio Prima, which is an open letter to Johannes Schöner, his Nürnberger astrology teacher and one of Johannes Petreius’ expert editors.

Johannes Schöner Source: Wikimedia Commons

The introduction also makes clear that he had promised Schöner, and probably through him Petreius, this report before leaving Nürnberg. Johannes Petreius’ dedicatory letter to Rheticus in his edition of the fourteenth-century physician Antonius de Motulmo’s De iudiciis nativitatumwas a direct response to the Narratio Prima. He goes on to give a very brief outline of the work, making no mention of the fact that Copernicus’ system is heliocentric. He says that he has mastered the first three books, of six, grasped a general idea of the forth and begun to conceive the hypotheses of the rest. He says he is going to skip the first two books for which he has a special plan; he originally intended to write a Narratio Secunda, which never materialised. He then plunges into his description.

The first four sections are technical astronomical accounts of: The Motion of the Fixed Stars, General Considerations of the Tropical Year, The Change in the Obliquity of the Ecliptic, and The Eccentricity of the Sun and the Motion of the Solar Apogee. In the fifth section, The Kingdom of the World Change with the Motion of the Eccentric, Rheticus changes tack completely and presents us with an astrological theory of cyclical historical change. I shall quote the beginning of this extraordinary section:

I shall add a prediction. We see that all kingdoms have had their beginnings when the centre of the eccentric was at a special point on the small circle. Thus, when the eccentricity of the sun was at its maximum, the Roman government became a monarchy; as the eccentricity decreased, Rome too declined, as aging, and then fell. When the eccentricity reached the boundary and quadrant of mean value, the Mohammedan faith was established; another great empire came into being and increased very rapidly, like the change in the eccentricity. A hundred years hence, when the eccentricity will be at its minimum, this empire too will complete its period.

…

This calculation does not differ much from the saying of Elijah, who prophesied under divine inspiration that the world would endure only 6,000 years, during which time nearly two revolutions are completed[2].

There is nothing about this to be found in Copernicus’ De revolutionibus but Copernicus certainly read the Narratio Prima before it was published and didn’t object to it or ask Rheticus to remove it. Such astrological cyclical theories of history were en vogue during the Early Modern Period. The most well known one was written by Johannes Carion (1499–1537), who together with Philipp Melanchthon was a student of Johannes Stöffler (1442–1531). Carion had also received language tuition from the slightly older Melanchthon.  Carion was court astrologer to the Elector Joachim I of Brandenburg (1484–1535).

Johann Carion, portrait by Lucas Cranach the Elder Source: Wikimedia Commons

Carion wrote a chronicle based on Biblical prophecies, which divided world history into three 2000-year periods. The chronicle was published shortly after Carion’s death. Following Carion’s death this chronicle passed into Melanchthon’s hands, who reworked it and published it again. Rheticus a student of Melanchthon obviously joined the Carion tradition in his astrological excurse in the Narratio Prima, which goes into long technical detail on the following pages.

In the next section Rheticus returns to Copernicus’ astronomy, Special Consideration of the Length of the Tropical Year. Up till now we have no indication at all from Rheticus that the system he is describing is a heliocentric one. We are now about one third of the way through and Rheticus’ next section is General Considerations Regarding the Motions of the Moon,Together with the New Lunar Hypothesis. At the end of this section we can read:

These phenomena, besides being ascribed to the planets, can be explained, as my teacher shows, by a regular motion of the spherical earth; that is, by having the sun occupy the centre of the universe, while the earth revolves instead of the sun on the eccentric, which it has pleased him to name the great circle. Indeed, there is something divine in the circumstance that a sure understanding of celestial phenomena must depend on the regular and uniform motions of the terrestrial globe alone.

He casual drops the information that we are indeed in a heliocentric world system in passing, as if were the most natural thing in the world. Having in the previous sections demonstrated Copernicus’ abilities as a theoretical astronomer he finally lets the cat out of the bag. There now follow eight sections in which he explains how the new hypothesis functions with the whole of astronomy.

The book closes with a non-astronomical section, In Praise of Prussia. This is a general polemic about how wonderful Prussia and the Prussian are and how well Rheticus has been received and treated by his Prussian hosts. It does, however, contain a section describing Giese’s attempts to persuade Copernicus to publish De revolutionibus and that Copernicus’ response to these enticements is to suggest that he will publish his tables of astronomical data without revealing the methods used to obtain them.

The Narratio Prima is dated 23 September 1539 by Rheticus, who took the manuscript to Danzig where it was printed and published by Franz Rhode in 1540 with the help of a donation towards the printing costs from Johann von Werden (c. 1495–1554) the mayor of Danzig. The title page is interesting as it begins with an honourable address to Johannes Schöner followed by The Books of Revolutions then an equally honourable naming of Copernicus but Rheticus, the author, is simply described as a young student of mathematics[3].

Title page of the 1st edition of the Narratio Prima Source: Wikimedia Commons

The Narratio Prima was fairly obviously conceived as a test balloon for Copernicus’ heliocentric hypothesis. It seems to have been well received and one recipient took his enthusiasm for the text much further. Rheticus had sent a copy to his mentor Achilles Pirmin Gasser (1505-1577),

Achilles Permin Gasser Source: Wikimedia Commons

who published a second edition of the book with a new dedicatory letter and Rheticus named on the title page in Basel in 1541.

First page of a later edition of the Narratio Prima with Rheticus named as author

The positive reception of the Narratio Prima and the lack of negative reactions seem to have finally convinced Copernicus to allow De revolutionibus to be published.

The Narratio Prima is rather long winded, strong on rhetoric and polemic but rather weak on its scientific content. There are no diagrams and Rheticus tends to rely on philosophical arguments rather than mathematical ones. He does, however, display a high degree or erudition, his text is full of classical quotes and allusions, which doesn’t actually make it easier for those who don’t have a classical eduction to plow through his, at times, rather turgid prose.

A third edition of the Narratio Prima was included in the second edition of De revolutionibus published by Heinric Petri in Basel in 1566. The forth and a fifth editions were included in the first and second editions of Johannes Kepler’s Mysterium Cosmographicum in 1597 and 1621. As such, more people probably learnt of Copernicus’ heliocentric system from the Narratio Prima than any other source.

Rheticus stayed in Frombork helping Copernicus to prepare his manuscript for publication by Petreius in Nürnberg. In October 1541 Rheticus left for Wittenberg, where he published an edited and improved version of the trigonometrical section of Derevolutionibusunder Copernicus’s name, De lateribus et angulis triangulorum (On the Sides and Angles of Triangles), which appeared in 1542.

This very useful publication also helped to increase Copernicus’ reputation in astronomical and mathematical circles. Rheticus would dedicate much of his future life to the publication of improved trigonometrical table.

In 1542 the manuscript of De revolutionibus arrived at Petreius’ printing office in Nürnberg followed by Rheticus who intended to see it through the press.

[1]There are no known portraits of Rheticus

[2]The Elijah prophecy is from the Talmud not the Bible.

[3]AD CLARISSMUM VIRUM D. IOANNEM SCHONERUM, DE LIBRIS REVOLUTIONUM eruditissimi viri & Mathematici excellentissimi, Reverendi D. Doctoris Nicolai Copernici Torunnaei, Canonici Varmiensis, per quendam Iuvenem, Mathematicae studiosum NARRATIO PRIMA (To that Famous Man Johann Schöner Concerning the Books of Revolutions of That Most Learned Man and Excellent Mathematician, the Venerable Doctor Nicolaus Copernicus of Toruń, Canon of Warmia, by a certain young student of mathematics)

 

 

The emergence of modern astronomy – a complex mosaic: Part VI

Copernicus first put his concept for a heliocentric cosmos in writing in a manuscript that today bears the title Nicolai Copernici de hypothesibus motuum coelestium a se constitutis commentariolus (roughly translated: Nicolas Copernicus’ short commentary on his hypothesis about the movement of the celestial bodies) of which three manuscripts are known to exist today. None of them, however, in Copernicus’ own handwriting. There is almost no direct evidence for the existence of this document in the sixteenth century and almost everything that we can say about its origin, its distribution and its impact is based on reasonable, speculative interpretation of indirect evidence.

It is disputed whether the title Commentariolus, for short, was written by Copernicus or was added at a later date; it has been speculated that it was added by Tycho Brahe, who possessed a copy, which is one of the three surviving copies and is now housed in the Viennese Court Library. In his Astronomiae Instauratae Progymnasmata (1602) Tycho wrote that his copy was given to him by Thaddaeus Hagecius (1525–1600). He also said that he had made several copies and distributed them to friends.

Title page of the Viennese Commentariolus manuscript Source: Wikimedia Commons

The Viennese manuscript was first found in 1877 but it is incomplete, missing a substantial part of Copernicus’ lunar theory. In 1881 a complete manuscript was found in the library of the Stockholm Observatory bound into a second edition of De Revolutionibus, which had been the property of Hevelius. The third manuscript was also found bound into a second edition of De revolutionibus that had belonged to Duncan Liddel (1561–1613) in the library of Saint Andrews University in Scotland. Liddel studied at various North German universities and was later a professor for mathematics at Helmstedt University before going on to qualify as a physician and becoming a professor for medicine. A fairly normal career path in the sixteenth century. He knew Tycho Brahe and visited him at least twice on the island of Hven. It should be noted that all three surviving copies of the Commentariolus were owned by people who lived after the publication of De revolutionibus and the death of its author.

The first probably mention of the Commentariolus occurred in 1514. The Cracovian physician, geographer and historian, Matthias of Miechow (1457–1523) noted in a library catalogue in the Jagiellonian Library dated 1 May 1514 the following:

Item sexternus theorice asserentis terram moveri, Solem vero quiescere

A quire of six leaves (sexternus) of a theory asserting that the Earth moves whereas the Sun is at rest.

It is assumed that this is a reference to the Commentariolus, probably a copy originally given by Copernicus to his Cracovian friend Canon Bernard Wapowski (1450–1535) a cartographer and historian.

Excerpt from the library catalogue of Matthias von Miechow (1457–1523) 1. Mai 1514 with the Commentariolus hint: „Item sexternus theorice asserentis terram moveri, Solem vero quiescere“. Source: Wikimedia Commons

There are no direct references to the Commentariolus before the publication of De Revolutionibus in 1543. However, there are various episodes in Copernicus’ life that can probably be attributed to knowledge of the Commentariolus.

Paul of Middelburg (1446–1534) sent out a general call to astronomers and rulers asking for suggestions and contributions towards a proposed calendar reform at the Lateran Council (1512–1517). Paul noted in 1516 that one of those who answered that call was Copernicus in a letter that no longer exists. Perhaps Copernicus was on Paul’s list because of the Commentariolus, he had at this point published no other astronomical works that might have motivate Paul to consult him.

In 1533 Johann Albrecht Widmannstetter (1506–1557), who was a papal secretary held a series of lectures to an audience of Pope Clement VII and some cardinals outlining Copernicus’ heliocentric theories for which he was richly rewarded by the Pope with a rare manuscript. It can be assumed that his source of knowledge of those theories was the Commentariolus.  Following the death of Pope Clement in 1534 Widmannstetter became secretary to Cardinal Nikolaus von Schönberg (1472–1537), who wrote a letter to Copernicus in 1536 concerning his theories and offering to have the manuscript of his theories (De revolutionibus) copied at his expense. This letter would be included in the published version of De revolutionibus.

In 1539 Martin Luther (1483–1546), in his cups, reputedly launched an attack on Copernicus’ heliocentric hypothesis, as recorded by Anton Lauterbach in the Tischreden (Table Talk) first published in 1566. (More details here)

There was mention of a certain astrologer who wanted to prove that the earth moves and not the sky, the sun, and the moon. This would be as if somebody were riding on a cart or in a ship and imagined that he was standing still while the earth and the trees were moving. [Luther remarked] “So it goes now. Whoever wants to be clever must agree with nothing that others esteem. He must do something of his own. This is what that fellow does who wishes to turn the whole of astronomy upside down. Even in these things that are thrown into disorder I believe the Holy Scriptures, for Joshua commanded the sun to stand still and not the earth [Jos. 10:12].”

Copernicus was not mentioned by name in Luther’s tirade and also no great details of the hypothesis. It can be assumed that indirect knowledge of the Commentariolus had come to Luther’s ears.

Our last possible indirect knowledge of the Commentariolus can be attributed to Georg Joachim Rheticus (1514–1574), who famously persuaded Copernicus to publish De revolutionibus. Rheticus set off for Frombork in 1539 already aware of the fact that Copernicus was propagating a heliocentric hypothesis. Did this knowledge come directly or indirectly from the Commentariolus?

So what does the Commentariolus consist of? In a very brief introduction Copernicus writes:

           Our Ancestors assumed, I observe, a large number of celestial spheres for this reason especially, to explain the apparent motion of the planets by the principle of regularity. For they thought it altogether absurd that a heavenly body, which is a perfect sphere, should not always move uniformly. They saw that by connecting and combining regular motions in various ways they could make any body appear to move to any position.

Callippus and Eudoxus, who endeavoured to solve the problem by use of concentric spheres, were unable to account for all planetary movements; they had to explain not merely the apparent revolutions of the planets but also the fact that these bodies appear to us sometimes to mount higher in the heavens, sometimes to descend; and this fact is incompatible with the principle of concentricity. Therefore it seemed better to employ eccentrics and epicycles, a system which most scholars finally accepted.

Yet the planetary theories of Ptolemy and most other astronomers, although consistent with the numerical data, seemed likewise to present no small difficulty. For these theories were not adequate unless certain equants were also conceived; it then appeared that a planet moved with uniform velocity neither on its deferent nor about the center of its epicycle. Hence a system of this sort seemed neither sufficiently absolute nor sufficiently pleasing to the mind.

Having become aware of these defects, I often considered whether there could perhaps be found a more reasonable arrangement of circles, from which every apparent inequality would be derived and in which everything would move uniformly about its proper center, as the rule of absolute motion require. After I had addressed myself to this very difficult and almost insoluble problem, the suggestion at length came to me how it could be solved with fewer and much simpler constructions than were formally used, if some assumptions (which are axioms) were granted me. They follow in this order[1].

In this brief introduction, which I have given here in full, Copernicus makes very clear why he thinks that astronomy needs reforming. He is in principle quite happy with an epicycle-deferent model but not with the use of equants, which he sees as violating the fundamental principle of uniform circular motion, a philosophically founded astronomical axiom that he wholeheartedly accepts. The equant point is an abstract off-centre point inside the orbit of a planet, which when used as the viewing point gives the planet on its epicycle-deferent uniform motion.

equant: A sphere that is centered at the center of the universe, but whose motion varies irregularly as if it were centered at another spot, called the equant point. This geometrical tool allowed Ptolemaic astronomers to construct orbits with the observed variations of speed without resorting to the ugliness of a sphere that was actually off center (an eccentric). The Planet is actually on the outer circle below, centered at E, the center of the universe. The sphere, however, moves as if it were centered at the point marked equant below, so that it takes equal times for the planet to move from 1 to 2, from 2 to 3, from 3 to 4 and from 4 back to 1, even though the distances vary. This produces a variation in the observed speed of the planet. Source

What is interesting is that he gives no indication of the bombshell that he is about to lob into the astronomy-cosmology debate with the assumptions that he wishes to be granted by his readers. They follow immediately on the introduction. He merely wishes to substitute a heliocentric system for the universally accepted geocentric system. Even more interesting, and totally frustrating for historians of astronomy, he gives absolutely no indication whatsoever how or why he came to adopt this radical step in order to rescue the uniform circular motion axiom. Copernicus’ assumptions (axioms) read as follows[2]:

1: There is no one center of all the celestial circles or spheres.

That there is, is one of the fundamental axioms of Aristotelian cosmology

2: The center of the earth is not the center of the universe, but only of gravity and the lunar sphere

That the earth is the centre of the universe is another of the Aristotelian axioms

3: All the spheres revolve about the sun as their mid-point, and therefore the sun is the center of the universe.

Bombshell lobed without comment!

4: The ratio of the earth’s distance from the sun to the height of the firmament is so much smaller than the ratio of the earth’s radius to its distance from the sun that the distance from the earth to the sun is imperceptible in comparison with the height of the firmament.

Copernicus needs this assumption to explain the lack of observable stellar parallax. Much is made of Copernicus’ vast increase in the size of the cosmos in comparison to Ptolemaeus. However in the Almagest Ptolemaeus states, “Moreover, the earth has, to the senses, the ratio of a point to the distance of the sphere of the so-called fixed stars[3].” Even Ptolemaeus’ cosmos is in principle unimaginably large.

5: Whatever motion appears in the firmament arises not from any motion of the firmament, but from the earth’s motion. The earth together with its circumjacent elements performs a complete rotation on its fixed poles in a daily motion, while the firmament and highest heaven abide unchanged.

The concept of diurnal rotation, the earth’s daily rotation about its own axis, had been hypothesised on many occasions throughout the history of astronomy as I explained in an earlier blog post. Copernicus would call upon some of those earlier examples as support for his own views in De revolutionibus. More interesting is the phrase “together with its circumjacent elements”, where Copernicus is basically saying that the earth carries its atmosphere with it when it rotates. This counters some of the arguments already listed by Ptolemaeus against diurnal rotation. The problem for Early Modern supporters of heliocentricity or simply diurnal rotation is they lacked the physics to explain how the earth could carry its atmosphere with in on its daily spin. We will return to this topic in a later episode.

6: What appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve around the sun like any other planet. The earth has, then, more than one motion.

The first sentence merely confirms the consequences of a heliocentric model. The second states another break with the Aristotelian axioms. According to Aristotle celestial bodies have just one type of natural motion, uniform circular motion and the earth also has just one type of natural motion upward or downward perpendicular to the earth’s surface.

7: The apparent retrograde and direct motion of the planets arises not from their motion but from the earth’s. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens.

This last assumption is, of course, the biggest selling point for the adoption of a heliocentric system but in the debates following the publication of De revolutionibus, the other arguments against heliocentricity weighed so heavily that this explanation for retrograde planetary motion got largely ignored.

Second page of the Stockholm manuscript with the assumptions Source: Wikimedia Commons

Copernicus now begins to fill in the details:

            Having set forth these assumptions, I shall endeavor briefly to show how uniformity of the motions can be saved in a systematic way. However I have thought it well, for the sake of brevity, to omit from this sketch mathematical demonstrations…[4]

Once again we have a confirmation that Copernicus’ main interest, as he sees it, is to restore the uniform circular motion axiom. I shall not into detail about the rest but the section headings are:

The Order of the Spheres

The Apparent Motion of the Sun

Equal Motion Should Be Measured Not by the Equinoxes but by the Fixed Stars

The Moon

The Three Superior Planets Saturn–Jupiter–Mars

Venus

Mercury[5]

Of interest here is that some of the epicycle-deferent models he outlines here differ from those that he would later develop for De revolutionibus indicating that this is an initial concept that would undergo development in the following thirty plus years, although he announces his intention to produce a larger more detailed work in the sentence I broke off above:

However I have thought it well, for the sake of brevity, to omit from this sketch mathematical demonstration, reserving these for my larger work[6].

We have no idea how many copies of the Commentariolus Copernicus made and distributed or how many further copies were made by others. As I have indicated above there is circumstantial evidence that it was read but the lack of any direct mentions before the publication of De revolutionibus, plus the fact that there seems to have been no heliocentricity debate triggered by it, as opposed to the debate triggered by Fracastoro’s Homocentrica (1538),and a couple of other contemporary published texts on the homocentric spheres model, indicate that the Commentariolus had very little impact on the sixteenth-century astronomical community.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[1]3 Copernican Treatises: The Commentariolus of Copernicus, The Letter Against Werner, The Narratio Prima of Rheticus, Translated with Introduction, Notes and Bibliography by Edward Rosen, Dover Publications, Inc., New York, 1959 pp. 57-58

[2]Copernicus/Rosen pp. 58-59

[3]Ptolemy’s AlmagestTranslated and Annotated by G. J. Toomer, Princeton University Press, Princeton New Jersey, ppb. 1998 p. 43

[4]Copernicus/Rosen p. 59

[5]Copernicus/Rosen pp. 59-90

[6]Copernicus/Rosen p. 59

The emergence of modern astronomy – a complex mosaic: Part IV

Part I  Part II Part III

There is general agreement amongst historians of science that a major factor in the emergence of modern science in general and modern astronomy in particular was the (re)invention of moveable type printing and the arrival of the printed book in the middle of the fifteenth century. I say reinvention because moveable type printing emerged twice before in China in the eleventh century CE and in Korea in the fourteenth century, as I explained in an earlier post. For a long time it was a commonplace in the historical narrative that the printed book, like gunpowder and the compass, was a Chinese invention but extensive long-term research has failed to produce any evidence of a technology transfer and it is now thought that Johannes Gutenberg’s was an independent invention. Even within Europe Gutenberg was not the first to experiment with moveable type and his real invention was the printing press, inclusive printing ink.

Book Printers from Jost Amman  Professionals and Craftsmen

Less than twenty years after Gutenberg published his Bible, Regiomontanus printed and published the first printed astronomy book Peuerbach’s Theoricae Novae Planetarum (Nürnberg, 1473) followed by a handful of other astronomy/astrology books. Unfortunately he died before he could publish their Epytoma in almagesti Ptolemei, which was first published by Ratdolt in Venice in 1496. Both titles became standard astronomy textbooks throughout Europe for more than one hundred years. Famously also being the texts from which Copernicus learnt his astronomy and cosmology.

Theoricae Novae Planetarum Source: Wikimedia Commons

This marked the start of a wave of printed astronomy/astrology books throughout the sixteenth and seventeenth centuries including the works of Apian, Copernicus, Tycho, Kepler, Galileo and many other less well-known figures. Printing made reliable, consistent text available to a wide circle of readers. Whereas a copy of a manuscript in Copenhagen might well have serious deviations compared with a manuscript of the same work in Venice, printed copies of a book were in theory the same wherever their owners lived and worked.

The Astronomer from Jost Amman’s Professionals and Craftsmen Source: Wikimedia Commons

As I pointed out in a reply to an earlier comment in this series the printed great works of astronomy, such as Copernicus’ De revolutionibusor Apian’s Astronomicum Caesareum, would have been way beyond the pocket of the average university student of the period but the professional astronomers, their patron and the institutions could and did acquire copies thus making them, at least potentially, accessible to those students. Interestingly Kepler bought a second hand copy of Copernicus’ De revolutionibus when he was still a student.

However, printing advanced the general dissemination and progress of astronomy and its related fields through purpose written textbooks. The most obvious example of this is Peter Apian’s Cosmographia, originally published by the author in Landshut in 1524. This was a basic introduction to astronomy, astrology, surveying, cartography etc. In total, over the sixteenth century, the book went through thirty-two expanded and improved editions all of which were, somewhat strangely, edited and published by Gemma Frisius and not Apian. Similar textbooks were produced by Oronce Fine, Michael Mästlin and many other sixteenth century mathematical authors.

Title page of Apian’s Cosmpgraphia

It was not just major monographs that profited from the invention of movable type printing. Such astronomical/astrological tools as ephemerides benefited from a certain level of consistency given by print as opposed to hand written manuscripts with their copying errors. In fact a large part of Regiomontanus’ posthumous reputation was based on his printed ephemeris, one of the few books he was able to publish before his untimely demise.

Regiomontanus also led the way in producing printed astronomical/astrological calendars, volumes much in demand from all those working in the wider field of astronomy. In fact astronomical/astrological ephemera of all types–calendars, prognostica, single-sheet wall calendars, almanacs–became a mainstay of the early printing industry providing a much need flow of ready cash.

Regiomontanus Calendar Source: University of Glasgow

To give an idea of the scope of this activity, one of the calendars of Simon Marius (1573–1625), which had to be withdrawn because of political complaints by the local authorities, was said by the printer publisher to have had an edition of 12,000. Marius was only a small local astrologer; the editions of the calendars and prognostica of an Apian or a Kepler would have been much larger. An astronomical monograph, such as De revolutionibus, would have had high production costs and an edition of maybe 500. It would take several years before it turned a profit for the printer publisher if at all. The author got nothing for his troubles. A calendar (wall or pocket), prognostica or almanac had comparatively low production costs, a large edition and if the author was established sold very rapidly. The profits were usually shared fifty-fifty between the printer and the author, a reliable stream of income for both parties. Gutenberg raised some of the finance for his Bible by printing and issuing an astro-medical single-sheet wall calendar.

In an important work, Astrology and the Popular Press: English Almanacs 1500–1800historian Bernard Capp showed that astrological ephemera made up by far and away the largest sector of publishing in the early centuries of printing and more importantly that the editorial sections of the cheap almanacs were one of the major sources for disseminating the latest developments in astronomy, in particular, in the seventeenth century, heliocentricity.

Almanack by John Tulley, 1692. Book exhibited in the Cambridge Public Library, Cambridge, Massachusetts Source: Wikimedia Commons

Along with the development of moving type printing came an increased use of illustrations leading to a rapid development in the techniques used to produce them–woodblock printing, copperplate engraving and etching.

Woodblock cutter Jost Amman’s Professionals and Craftsmen Source: Wikimedia Commons

These techniques were then extended to other field related to astronomy, cartography and globe making. Printed copies of Ptolemaeus’ Geographia with maps were already being printed in the last quarter of the fifteenth century. There also quickly developed a market for large scale printed wall maps, the most famous early example being Waldseemüller’s world map that gave the very recently discovered fourth part of the world the name America after Amerigo Vespucci (1454–1512). Waldseemüller also seems to have printed the first terrestrial globe, a small globe containing the same map of the world. Unfortunately we only have a small number of printed globe gores and no surviving finished globes.

Waldseemüller World Map 1507 (Wikipedia Commons)

Johannes Schöner (1477–1547) was the first to start producing serial printed globes, his first terrestrial globe in 1515 and the matching celestial globe in 1517, establishing a tradition for matching pairs of printed globes that continued until the end of the nineteenth century. Judging by comments from his correspondence his globe printing enterprise was both very successful and very lucrative. Gemma Frisius (1508–1555) took up the baton producing printed globes to be sold with reprints of Schöner’s cosmographia, the descriptive book sold with each globe to explain how to use it. Gemma’s assistant was Gerhard Mercator, who would go on to become the most successful printed globe maker of the second half of the sixteenth century. Mercator’s globes inspired both the great Dutch cartographical houses of Hondius and Blaeu, who would dominate the European globe making and cartography industry in the seventeenth century. England’s first commercial globe printer, Joseph Moxon (1627–1691) learnt his handwork from Willem Janszoon Blaeu (c. 1570–1630). Printed globe making was big business in the sixteenth and seventeenth centuries and the globes were used to teach both astronomy and astrology.

Pair of globes by Gerard Mercator (Globe Museum, Austrian National Library).

Of course all of the above applies equally well to printed maps. Along with the demand for large wall maps, a market developed for collections of printed maps, what we now call atlases. Bound collection of manuscript maps existed before the invention of printing but being the product of hundreds of hours of manual labour these tended to be art treasures for rich patrons rather than practical books for everyday usage. The man, who did most to change this was Abraham Ortelius (1527–1598), whose Theatrum Orbis Terrarum, a bound, standardised, collection of maps, produced especially for traders first published in 1570 was a runaway success. Initial less successful was the more academic Atlas of his good friend and rival Gerhard Mercator. However, both publications laid the foundations for the commercial success of the cartographical publications of Blaeu and Hondius.

Theatrum Orbis Terrarum Title Page Source: Wikimedia Commons

A somewhat different approach was taken by Sebastian Münster (1488–1552), with his Cosmographia, first published in 1544, which was not just a collection of maps but also a full geographical and historical description of the world. In its numerous editions it was almost certainly the biggest selling book in the sixteenth century.

Title page of the first edition of Münster’s Cosmographia Source: Wikimedia Commons

Like nearly-all-the-other globe makers and cartographers described here Münster was an astrologer and astronomer. Other astrologer/astronomers in the sixteenth century, who were also commercially successful as cartographers were Peter and Philipp Apian, Oronce Fine and Michael Mästlin.

It should be clear from the above that the advent of movable type printing had a very large impact on the dissemination of astronomy and its related fields at the same time raising its status in the Early Modern Period in Europe and bringing it to a much wider audience.