Category Archives: History of Technology

The problem with Jonathan Jones and #histSTM

It cannot be said that I am a fan of Jonathan Jones The Guardian’s wanna be art critic but although I find most of his attempts at art criticism questionable at best, as a historian of science I am normal content to simply ignore him. However when he strays into the area of #histSTM I occasionally feel the desire to give him a good kicking if only a metaphorical one. In recent times he has twice committed the sin of publicly displaying his ignorance of #histSTM thereby provoking this post. In both cases Leonard da Vinci plays a central role in his transgressions, so I feel the need to make a general comment first. Many people are fascinated by Leonardo and some of them feel the need to express that fascination in public. These can be roughly divided into two categories, the first are experts who have seriously studied Leonardo and whose utterances are based on knowledge and informed analysis, examples of this first group are Matin Kemp the art historian and Monica Azzolini the Renaissance historian. The second category could be grouped together under the title Leonardo groupies and their utterances are mostly distinguished by lack of knowledge and often mind boggling stupidity. Jonathan Jones is definitely a Leonardo groupie.

Jones’ first foray into the world of #histSTM on 28 January with a piece entitled, The charisma droids: today’s robots and the artists who foresaw them, which is a review of the new major robot exhibition at the Science Museum. What he has to say about the exhibition doesn’t really interest me here but in the middle of his article we stumble across the following paragraph:

So it is oddly inevitable that one of the first recorded inventors of robots was Leonardo da Vinci, consummate artist and pioneering engineer [my emphasis]. Leonardo apparently made, or at least designed, a robot knight to amuse the court of Milan. It worked with pulleys and was capable of simple movements. Documents of this invention are frustratingly sparse, but there is a reliable eyewitness account of another of Leonardo’s automata. In 1515 he delighted Francois I, king of France, with a robot lion that walked forward towards the monarch, then released a bunch of lilies, the royal flower, from a panel that opened in its back.

Now I have no doubts that amongst his many other accomplishments Leonardo turned his amazingly fertile thoughts to the subject of automata, after all he, like his fellow Renaissance engineers, was a fan of Hero of Alexandria who wrote extensively about automata and also constructed them. Here we have the crux of the problem. Leonardo was not “one of the first recorded inventors of robots”. In fact by the time Leonardo came on the scene automata as a topic of discussion, speculation, legend and myth had already enjoyed a couple of thousand years of history. If Jones had taken the trouble to read Ellie Truitt’s (@MedievalRobots) excellent Medieval Robots: Mechanism, Magic, Nature and Art (University of Pennsylvania Press, 2015) he would have known just how wrong his claim was. However Jones is one of those who wish to perpetuate the myth that Leonardo is the source of everything. Actually one doesn’t even need to read Ms. Truitt’s wonderful tome, you can listen to her sketching the early history of automata on the first episode of Adam Rutherford’s documentary The Rise of the Robots on BBC Radio 4, also inspired by the Science Museums exhibition. The whole series is well worth a listen.

On 6 February Jones took his Leonardo fantasies to new heights in a piece, entitled Did the Mona Lisa have syphilis? Yes, seriously that is the title of his article. Retro-diagnosis in historical studies is a best a dodgy business and should, I think, be avoided. We have whole libraries of literature diagnosing Joan of Arc’s voices, Van Gough’s mental disorders and the causes of death of numerous historical figures. There are whole lists of figures from the history of science, including such notables as Newton and Einstein, who are considered by some, usually self declared, experts to have suffered from Asperger’s syndrome. All of these theories are at best half way founded speculations and all too oft wild ones. So why does Jonathan Jones think that the Mona Lisa had syphilis? He reveals his evidence already in the sub-title to his piece:

Lisa del Giocondo, the model for Leonardo’s painting, was recorded buying snail water – then considered a cur for the STD: It could be the secret to a painting haunted by the spectre of death.

That’s it folks don’t buy any snail water or Jonathan Jones will think that you have syphilis.

Let’s look at the detail of Jones’ amazingly revelatory discovery:

Yet, as it happens, a handful of documents have survived that give glimpses of Del Giocondo’s life. For instance, she is recorded in the ledger of a Florentine convent as buying snail water (acqua di chiocciole) from its apothecary.

Snail water? I remember finding it comical when I first read this. Beyond that, I accepted a bland suggestion that it was used as a cosmetic or for indigestion. In fact, this is nonsense. The main use of snail water in pre-modern medicine was, I have recently discovered, to combat sexually transmitted diseases, including syphilis.

So she bought some snail water from an apothecary, she was the female head of the household and there is absolutely no evidence that she acquired the snail water for herself. This is something that Jones admits but then casually brushes aside. Can’t let ugly doubts get in the way of such a wonderful theory. More importantly is the claim that “the main use of snail water snail water in pre-modern medicine was […] to combat sexually transmitted diseases, including syphilis” actually correct? Those in the know disagree. I reproduce for your entertainment the following exchange concerning the subject from Twitter.

Greg Jenner (@greg_jenner)

Hello, you may have read that the Mona Lisa had syphilis. This thread points out that is probably bollocks

 Dubious theory – the key evidence is her buying “snail water”, but this was used as a remedy for rashes, earaches, wounds, bad eyes, etc…

Greg Jenner added,

Seen this ‪@DrAlun ‪@DrJaninaRamirez ? What say you? I’ve seen snail water used in so many different Early Modern remedies

Alun Withey (@DrAlun)

I think it’s an ENORMOUS leap to that conclusion. Most commonly I’ve seen it for eye complaints.

Greg Jenner

‪@DrAlun @DrJaninaRamirez yeah, as I thought – and syphilis expert @monaob1 agrees

 Alun Withey

‪@greg_jenner @DrJaninaRamirez @monaob1 So, the burning question then, did the real Mona Lisa have sore eyes? It’s a game-changer!

Mona O’Brian (@monaob1)

‪@DrAlun @greg_jenner @DrJaninaRamirez interested to hear the art historical interpretation on the ‘unhealthy’ eyes comment!

Alun Withey

‪@monaob1 @greg_jenner @DrJaninaRamirez doesn’t JJ say in the article there’s a shadow around her eyes? Mystery solved. *mic drop*

Greg Jenner

‪@DrAlun @monaob1 @DrJaninaRamirez speaking as a man who recently had to buy eye moisturiser, eyes get tired with age? No disease needed

 Mona O’Brian

@greg_jenner Agreed! Also against the pinning of the disease on the New World, considering debates about the disease’s origin are ongoing

Jen Roberts (@jshermanroberts)

‪@greg_jenner I just wrote a blog post about snail water for @historecipes –common household cure for phlegmy complaints like consumption.

Tim Kimber (@Tim_Kimber)

‪@greg_jenner Doesn’t the definite article imply the painting, rather than the person? So they’re saying the painting had syphilis… right?

Minister for Moths (@GrahamMoonieD)

‪@greg_jenner but useless against enigmatic smiles

Interestingly around the same time an advert was doing the rounds on the Internet concerning the use of snail slime as a skin beauty treatment. You can read Jen Roberts highly informative blog post on the history of snail water on The Recipes Project, which includes a closing paragraph on modern snail facials!




Filed under History of medicine, History of Technology, Renaissance Science, Uncategorized

Why Mathematicus?

“The Renaissance Mathematiwot?”

“Mathematicus, it’s the Latin root of the word mathematician.”

“Then why can’t you just write The Renaissance Mathematician instead of showing off and confusing people?”

“Because a mathematicus is not the same as a mathematician.”

“But you just said…”

“Words evolve over time and change their meanings, what we now understand as the occupational profile of a mathematician has some things in common with the occupational profile of a Renaissance mathematicus but an awful lot more that isn’t. I will attempt to explain.”

The word mathematician actually has its origins in the Greek word mathema, which literally meant ‘that which is learnt’, and came to mean knowledge in general or more specifically scientific knowledge or mathematical knowledge. In the Hellenistic period, when Latin became the lingua franca, so to speak, the knowledge most associated with the word mathematica was astrological knowledge. In fact the terms for the professors[1] of such knowledge, mathematicus and astrologus, were synonymous. This led to the famous historical error that St. Augustine rejected mathematics, whereas his notorious attack on the mathematici[2] was launched not against mathematicians, as we understand the term, but against astrologers.

The earliest known portrait of Saint Augustine in a 6th-century fresco, Lateran, Rome Source: Wikimedia Commons

The earliest known portrait of Saint Augustine in a 6th-century fresco, Lateran, Rome
Source: Wikimedia Commons

However St. Augustine lived in North Africa in the fourth century CE and we are concerned with the European Renaissance, which, for the purposes of this post we will define as being from roughly 1400 to 1650 CE.

The Renaissance was a period of strong revival for Greek astrology and the two hundred and fifty years that I have bracketed have been called the golden age of astrology and the principle occupation of our mathematicus is still very much the casting and interpretation of horoscopes. Mathematics had played a very minor role at the medieval universities but the Renaissance humanist universities of Northern Italy and Krakow in Poland introduced dedicated chairs for mathematics in the early fifteenth century, which were in fact chairs for astrology, whose occupants were expected to teach astrology to the medical students for their astro-medicine or as it was known iatro-mathematics. All Renaissance professors of mathematics down to and including Galileo were expected to and did teach astrology.

A Renaissance Horoscope Kepler's Horoskop für Wallenstein Source: Wikimedia Commons

A Renaissance Horoscope
Kepler’s Horoskop für Wallenstein
Source: Wikimedia Commons

Of course, to teach astrology they also had to practice and teach astronomy, which in turn required the basics of mathematics – arithmetic, geometry and trigonometry – which is what our mathematicus has in common with the modern mathematician. Throughout this period the terms Astrologus, astronomus and mathematicus – astrologer, astronomer and mathematician ­– were synonymous.

A Renaissance mathematicus was not just required to be an astronomer but to quantify and describe the entire cosmos making him a cosmographer i.e. a geographer and cartographer as well as astronomer. A Renaissance geographer/cartographer also covered much that we would now consider to be history, rather than geography.

The Renaissance mathematicus was also in general expected to produce the tools of his trade meaning conceiving, designing and manufacturing or having manufactured the mathematical instruments needed for astronomer, surveying and cartography. Many were not just cartographers but also globe makers.

Many Renaissance mathematici earned their living outside of the universities. Most of these worked at courts both secular and clerical. Here once again their primary function was usually court astrologer but they were expected to fulfil any functions considered to fall within the scope of the mathematical science much of which we would see as assignments for architects and/or engineers rather than mathematicians. Like their university colleagues they were also instrument makers a principle function being horologist, i.e. clock maker, which mostly meant the design and construction of sundials.

If we pull all of this together our Renaissance mathematicus is an astrologer, astronomer, mathematician, geographer, cartographer, surveyor, architect, engineer, instrument designer and maker, and globe maker. This long list of functions with its strong emphasis on practical applications of knowledge means that it is common historical practice to refer to Renaissance mathematici as mathematical practitioners rather than mathematicians.

This very wide range of functions fulfilled by a Renaissance mathematicus leads to a common historiographical problem in the history of Renaissance mathematics, which I will explain with reference to one of my favourite Renaissance mathematici, Johannes Schöner.

Joan Schonerus Mathematicus Source: Wikimedia Commons

Joan Schonerus Mathematicus
Source: Wikimedia Commons

Schöner who was a school professor of mathematics for twenty years was an astrologer, astronomer, geographer, cartographer, instrument maker, globe maker, textbook author, and mathematical editor and like many other mathematici such as Peter Apian, Gemma Frisius, Oronce Fine and Gerard Mercator, he regarded all of his activities as different aspects or facets of one single discipline, mathematica. From the modern standpoint almost all of activities represent a separate discipline each of which has its own discipline historians, this means that our historical picture of Schöner is a very fragmented one.

Because he produced no original mathematics historians of mathematics tend to ignore him and although they should really be looking at how the discipline evolved in this period, many just spring over it. Historians of astronomy treat him as a minor figure, whilst ignoring his astrology although it was this that played the major role in his relationship to Rheticus and thus to the publication of Copernicus’ De revolutionibus. For historians of astrology, Schöner is a major figure in Renaissance astrology although a major study of his role and influence in the discipline still has to be written. Historians of geography tend to leave him to the historians of cartography, these whilst using the maps on his globes for their studies ignore his role in the history of globe making whilst doing so. For the historians of globe making, and yes it really is a separate discipline, Schöner is a central and highly significant figure as the founder of the long tradition of printed globe pairs but they don’t tend to look outside of their own discipline to see how his globe making fits together with his other activities. I’m still looking for a serious study of his activities as an instrument maker. There is also, as far as I know no real comprehensive study of his role as textbook author and editor, areas that tend to be the neglected stepchildren of the histories of science and technology. What is glaringly missing is a historiographical approach that treats the work of Schöner or of the Renaissance mathematici as an integrated coherent whole.

Western hemisphere of the Schöner globe from 1520. Source: Wikimedia Commons

Western hemisphere of the Schöner globe from 1520.
Source: Wikimedia Commons

The world of this blog is at its core the world of the Renaissance mathematici and thus we are the Renaissance Mathematicus and not the Renaissance Mathematician.

[1] That is professor in its original meaning donated somebody who claims to possessing a particular area of knowledge.

[2] Augustinus De Genesi ad Litteram,

Quapropter bono christiano, sive mathematici, sive quilibet impie divinantium, maxime dicentes vera, cavendi sunt, ne consortio daemoniorum animam deceptam, pacto quodam societatis irretiant. II, xvii, 37


Filed under History of Astrology, History of Astronomy, History of Cartography, History of Mathematics, History of science, History of Technology, Renaissance Science

Christmas Trilogy 2016 Part 2: What a difference an engine makes

Charles Babbage is credited with having devised the first ever special-purpose mechanical computer as well as the first ever general-purpose mechanical computer. The first claim seems rather dubious in an age where there is general agreement that the Antikythera mechanism is some sort of analogue computer. However, Babbage did indeed conceive and design the Difference Engine, a special purpose mechanical computer, in the first half of the nineteenth century. But what is a Difference Engine and why “Difference”?

Both Babbage and John Herschel were deeply interested in mathematical tables – trigonometrical tables, logarithmic tables – when they were still students and Babbage started collecting as many different editions of such tables as he could find. His main object was to check them for mistakes. Such mathematical tables were essential for navigation and errors in the figures could lead to serious navigation error for the users. Today if I want to know the natural logarithm of a number, let’s take 23.483 for example, I just tip it into my pocket calculator, which cost me all of €18, and I instantly get an answer to nine decimal places, 3.156276755. In Babbage’s day one would have to look the answer up in a table each value of which had been arduously calculated by hand. The risk that those calculations contained errors was very high indeed.

Babbage reasoned that it should be possible to devise a machine that could carryout those arduous calculations free of error and if it included a printer, to print out the calculated answer avoiding printing errors as well. The result of this stream of thought was his Difference Engine but why Difference?

The London Science Museum's reconstruction of Difference Engine No. 2 Source: Wikimedia Commons

The London Science Museum’s reconstruction of Difference Engine No. 2
Source: Wikimedia Commons

Babbage needed to keep his machine as simple as possible, which meant that the simplest solution would be a machine that could calculate all the necessary tables with variations on one algorithm, where an algorithm is just a step-by-step recipe to solve a mathematical problem. However, he needed to calculate logarithms, sines, cosines and tangents, did such an algorithm exist. Yes it did and it had been discovered by Isaac Newton and known as the method of finite differences.

The method of finite differences describes a property shared by all polynomials. If it has been a while since you did any mathematics, polynomials are mathematical expressions of the type x2+5x-3 or 7x5-3x3+2x2-3x+6 or x2-2 etc, etc. If you tabulate the values of a given polynomial for x=0, x=1, x=2, x=3 and so on then subtract the first value from the second, the second from the third and so on you get a new column of numbers. Repeating the process with this column produces yet another column and so on. At some point in the process you end up with a column that is filled with a numerical constant. Confused? OK look at the table below!


x x3-3x2+6 xn+1-xn diff(1)n+1 –diff(1)n diff(2)n+1 – diff(2)n
0 6 -2 0 6
1 4 -2 6 6
2 2 4 12 6
3 6 16 18
4 22 34
5 56


As you can see this particular polynomial bottoms out, so to speak, with as constant of 6. If we now go back into the right hand column and enter a new 6 in the first free line then add this to its immediate left hand neighbour repeating this process across the table we arrive at the polynomial column with the next value for the polynomial. See below:


x x3-3x2+6 xn+1-xn diff(1)n+1 –diff(1)n diff(2)n+1 – diff(2)n
0 6 -2 0 6
1 4 -2 6 6
2 2 4 12 6
3 6 16 18 6
4 22 34
5 56


x x3-3x2+6 xn+1-xn diff(1)n+1 –diff(1)n diff(2)n+1 – diff(2)n
0 6 -2 0 6
1 4 -2 6 6
2 2 4 12 6
3 6 16 18 6
4 22 34 24
5 56


x x3-3x2+6 xn+1-xn diff(1)n+1 –diff(1)n diff(2)n+1 – diff(2)n
0 6 -2 0 6
1 4 -2 6 6
2 2 4 12 6
3 6 16 18 6
4 22 34 24
5 56 58


x x3-3x2+6 xn+1-xn diff(1)n+1 –diff(1)n diff(2)n+1 – diff(2)n
0 6 -2 0 6
1 4 -2 6 6
2 2 4 12 6
3 6 16 18 6
4 22 34 24
5 56 58
6 114

This means that if we set up our table and calculate enough values to determine the difference constant then we can by a process of simple addition calculate all further values of the polynomial. This is exactly what Babbage designed his difference engine to do.

If you’ve been paying attention you might notice that the method of finite differences applies to polynomials and Babbage wished to calculate were logarithmic and trigonometrical functions. This is however not a serious problem, through the use of other bits of higher mathematics, which we don’t need to go into here, it is possible to represent both logarithmic and trigonometrical functions as polynomials. There are some problems involved with using the method of finite differences with these polynomials but these are surmountable and Babbage was a good enough mathematician to cope with these difficulties.

Babbage now had a concept and a plan to realise it, all he now needed was the finances to put his plan into action. This was not a problem. Great Britain was a world power with a large empire and the British Government was more than ready to cough up the readies for a scheme to provide reliable mathematical tables for navigation for the Royal Navy and Merchant Marine that serviced, controlled and defended that empire. In total over a period of about ten years the Government provided Babbage with about £17, 000, literally a fortune in the early nineteen hundreds. What did they get for their money, in the end nothing!

Why didn’t Babbage deliver the Difference Engine? There is a widespread myth that Babbage’s computer couldn’t be built with the technology available in the first half of the nineteenth century. This is simply not true, as I said a myth. Several modules of the Difference Engine were built and functioned perfectly. Babbage himself had one, which he would demonstrate at his scientific soirées, amongst other things to demonstrate his theory of miracles.

The Difference Engine model used by Babbage for his demonstrations of his miracle theory Source: Wikimedia Commons

The Difference Engine model used by Babbage for his demonstrations of his miracle theory
Source: Wikimedia Commons

Other Difference Engines modules were exhibited and demonstrated at the Great Exhibition in Crystal Palace. So why didn’t Babbage finish building the Difference Engine and deliver it up to the British Government? Babbage was not an easy man, argumentative and prone to bitter disputes. He became embroiled in one such dispute with Joseph Clement, the engineer who was actually building the Difference Engine, about ownership of and rights to the tools developed to construct the engine and various already constructed elements. Joseph Clement won the dispute and decamped together with said tools and elements. By now Babbage was consumed with a passion for his new computing vision, the general purpose Analytical Engine. He now abandoned the Difference Engine and tried to convince the government to instead finance the, in his opinion, far superior Analytical Engine. Having sunk a fortune into the Difference Engine and receiving nothing in return, the government, not surprisingly, demurred. The much hyped Ada Lovelace Memoire on the Analytical Engine was just one of Babbage’s attempts to advertise his scheme and attract financing.

However, the story of the Difference Engine didn’t end there. Using knowledge that he had won through his work on the Analytical Engine, Babbage produced plans for an improved, simplified Difference Engine 2 at the beginning of the 1850s.

Per Georg Schutz Source: Wikimedia Commons

Per Georg Schutz
Source: Wikimedia Commons

The Swedish engineer Per Georg Scheutz, who had already been designing and building mechanical calculators, began to manufacture difference engines based on Babbage’s plans for the Difference Engine 2 in 1855. He even sold one to the British Government.

Scheutz Difference Engine No. 2. (1859) Maschine im Science Museum, London Source: Wikimedia Commons

Scheutz Difference Engine No. 2. (1859) Maschine im Science Museum, London
Source: Wikimedia Commons


Filed under History of Computing, History of Mathematics, History of Technology, Myths of Science

Werner von Siemens and Erlangen

I (almost)[1] live in the town of Erlangen in Franconia, in Southern Germany. Erlangen is a university town with an official population of about 110 000. I say official because Erlangen has a fairly large number of inhabitants, mostly student, who are registered as living elsewhere with Erlangen as their second place of residence, who are not included in the official population numbers. I suspect that the population actually lies somewhere between 120 and 130 000. Erlangen is dominated by the university, which currently has 40 000 students, although several departments are in the neighbouring towns of Furth and Nürnberg, and is thus the second largest university in Bavaria, and the company Siemens. Siemens, one of Germany’s largest industrial firms, is a worldwide concern and Erlangen is after Berlin and Munich the third largest Siemens centre in Germany, home to large parts of the company’s research and development. It is the home of Siemens’ medical technology branch, Siemens being a world leader in this field. 13 December is the two hundredth anniversary of the birth of Werner von Siemens the founder of the company.

Werner von Siemens (Portrait by Giacomo Brogi) Source: Wikimedia Commons

Werner von Siemens (Portrait by Giacomo Brogi)
Source: Wikimedia Commons

Werner Siemens (the von came later in his life) was born in Lenthe near Hanover the fourth child of fourteenth children of the farmer Christian Ferdinand Siemens and his wife Eleonore Henriette Deichmann on13 December 1894. The family was not wealthy and Werner was forced to end his education early. In 1835 he joined the artillery corps of Prussian Army in order to get an education in science and engineering; he graduated as a lieutenant in 1838.

Werner Siemens as Second-Lieutenant in the Prussian Artillery, 1842 Source: Wikimedia Commons

Werner Siemens as Second-Lieutenant in the Prussian Artillery, 1842
Source: Wikimedia Commons

He was sentenced to five years in military prison for acting as a second in a duel but was pardoned in 1842 and took up his military service. Whilst still in the army he developed an improved version of Wheatstone’s and Cooke’s electrical telegraph in 1846 and persuaded the Prussian Army to give his system field trials in 1847. Having proved the effectiveness of his system Siemens patented it and in the same year founded together with the fine mechanic Johann Georg Halske the Telegraphen-Bauanstalt von Siemens & Halske. They received a commission to construct Prussia’s first electrical telegraph line from Berlin to Frankfurt, which was completed in 1849, when Werner left the army to become an electrical engineer and entrepreneur. The profession of electrical engineer didn’t exist yet and Werner Siemens is regarded as one of its founders.

Pointer telegraph, 1847 (replica) Source: Siemens

Pointer telegraph, 1847 (replica)
Source: Siemens

Already a successful electrical telegraph construction company the next major step came when Werner discovered the principle of dynamo self-excitation in 1867, which enabled the construction of the worlds first practical electric generators. Werner was not alone in making this discovery. The Hungarian Anyos Jedlik discovered it already in 1856 but didn’t patent it and his discovery remained unknown and unexploited. The Englishman Samuel Alfred Avery patented a self-exciting dynamo in 1866, one year ahead of both Siemens and Charles Wheatstone who also independently made the same discovery.

Structure (with cross section) of the dynamo machine 1866 Source: Siemens

Structure (with cross section) of the dynamo machine 1866
Source: Siemens

Throughout his life Werner Siemens combined the best attributes of a scientists, an engineer, an inventor and an entrepreneur constantly pushing the range of his companies products. He developed the use of gutta-percha as material for cable insolation, Siemens laying the first German transatlantic telegraph cable with their own specially constructed cable laying ship The Faraday in 1874. The world’s first electric railway followed in 1879, the world’s first electric tram in 1881 and the world’s first trolleybus in 1882.

The Faraday, cable laying ship of Siemens Brothers & Co. 1874 Source: Wikimedia Commons

The Faraday, cable laying ship of Siemens Brothers & Co. 1874
Source: Wikimedia Commons

Werner Siemens was a great believer in scientific research and donated 500,000 Marks (a fortune), in land and cash, in 1884 towards the establishment of the Physikalisch-Technische Reichsanstalt a state scientific research institute, which finally came into being in 1887 and lives on today under the name Physikalisch-Technische Bundesanstalt (PTB). From the very beginning Werner Siemens thought in international terms sending his brother Wilhelm off to London in 1852 to represent the company and another brother Carl to St Petersburg in 1853, where Siemens built Russia’s first telegraph network. In 1867 Halske left the company and Carl and Wilhelm became partners making Siemens a family company. In 1888, four years before his death, Werner was ennobled becoming Werner von Siemens.

The research and development department of Siemens moved to Erlangen after the Second World War, as their home in Berlin became an island surrounded by the Russian occupation zone. Erlangen was probably chosen because it was already the home of Siemens’ medical technology section. In order to understand how this came to be in Erlangen we need to go back to the nineteenth century and the live story of Erwin Moritz Reiniger.

Siemens-Administration in the 1950s „Himbeerpalast“ Designed by  Hans Hertlein  Note the Zodiac clock dial Source: Wikimedia Commons

Siemens-Administration in the 1950s „Himbeerpalast“ Designed by Hans Hertlein
Note the Zodiac clock dial
Source: Wikimedia Commons

Reiniger born 5 April 154 in Stuttgart was employed as an experiment demonstrator at the University of Erlangen in 1876. He was also responsible for the repair of technical equipment in the university institutes and clinics. Realising that this work could become highly profitable, Reiniger set up as a self-employed fine mechanic in Schlossplatz 3 next door to the university administration in the Schloss (palace) in 1877, producing fine mechanical, physical, optical and simple electro-medical instruments.

Schloss Erlangen (university Administration) Source: Wikimedia Commons

Schloss Erlangen
(University Administration)
Source: Wikimedia Commons

Schlossplatz 3. Site of Reindeer's original workshop Source: Wikimedia Commons

Schlossplatz 3. Site of Reiniger’s original workshop
Source: Wikimedia Commons

Plaque on Schlossplatz 3

Plaque on Schlossplatz 3

By 1885 Reiniger was employing fifteen workers. In 1886 he went into partnership with the mechanics Max Gebbert and Karl Friedrich Schall forming the Vereinigte physikalisch-mechanische Werkstätten von Reiniger, Gebbert & Schall– Erlangen, New York, Stuttgart (RGS). The workshops in New York and Stuttgart were soon abandoned and the company concentrated on Erlangen. Karl Schall left the company in 1888 and Reiniger was bought out by Gebbert in 1895.

Reiniger Gebiert & Schall Letterhead 1896 Source: Wikimedia Commons

Reiniger Gebiert & Schall Letterhead 1896
Source: Wikimedia Commons

Wilhelm Conrad Röntgen discovered X-rays on 8 November 1895 and published his discovery in three scientific papers between then and January 1896.

Wilhelm Conrad Röntgen Source: Wikimedia Commons

Wilhelm Conrad Röntgen
Source: Wikimedia Commons

Famously he didn’t patent his discovery and RGS were already, as the very first company in the world, producing X-ray tubes and X-ray machines in 1896 and this would become the mainstay of their business. There is a rather sweet letter in the Siemens archive from Röntgen, who was professor in Würzburg, not too far away from Erlangen, asking if he could possibly get a rebate if he purchased his X-ray tubes from RGS.

Reiniger, Gebbert & Schall AG Factory in Erlangen constructed in 1883. Now a protected building. Source: Wikimedia Commons

Reiniger, Gebbert & Schall AG Factory in Erlangen constructed in 1883. Now a protected building.
Source: Wikimedia Commons

Following the First World War, RGS got into financially difficulties due to bad management and in 1925 the company was bought by Siemens & Halske, who transferred their own medical technology production to Erlangen thus establishing the medical technology division of Siemens in Erlangen where it still is today. Originally called the Siemens-Reiniger-Werke AG it has gone through more name changes than I care to remember currently being called ‘Healthineers’ to the amusement of the local population, who on the whole find the name ridiculous.

Siemens Medical Museum in the Reiniger, Gebbert & Schall AG Factory Building

Siemens Medical Museum in the Reiniger, Gebbert & Schall AG Factory Building

What of the future? Last week saw the laying of the foundation stone of the new Siemens Campus in Erlangen a 500 million Euro building project to provide Siemens with a new R&D centre for the twenty-first century.

Siemens Campus Architects Model

Siemens Campus Architects Model



[1] I actually live in a small village on the outskirts of Erlangen but the town boundary is about 150 metres, as the crow flies, from where I am sitting typing this post.


Filed under History of Physics, History of science, History of Technology

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

Printing mistakes

Today during my usual early morning perusal of my Twitter steam I came across the following tweet:

Today is not just the anniv. Of Gutenberg printing his first bible, this is the day of our literacy liberation

Now I found this tweet, to say the least, more than somewhat bizarre, as we are not even certain in which year Gutenberg printed his first bible let alone on which day. In fact it is absolutely certain that there was no publication date for this epoch defining work but that it rather dribbled gradually into the public sphere over quite a wide period of time. That this supposed anniversary is totally fictitious is confirmed by a Time magazine article from yesterday:

It’s hard to pin down the exact day the book was born, but August 24 is as fine a day to celebrate as any: it was on this day in 1456 that at least one copy of the original Gutenberg Bible was completed.

It seems that it is in order now to make up historical anniversaries.

My curiosity awakened I read through the responses to this tweet and stumbled across this even more fascinating claim concerning the history of printing:

How about “Muslims were practising the craft of printing for some five centuries before Gutenberg”

Now I’ve read an awful lot about the history of printing and although I’m well aware that Gutenberg was by no means the first person to invent movable type I was not familiar with any Muslim predecessors, in fact I thought the exact opposite to be true; that is the Arabic Empire had never invented our acquired movable type printing. So it was with some interest that I followed the supplied link to an article with the title Muslim Printing Before Gutenberg.

The article starts with a whole paragraph presenting an overblown statement of the author’s qualifications and expertise for writing the article. I wouldn’t mention this if the article didn’t contain a fundamental flaw, which I will elucidate shortly and which no qualified expert should have made. We will let the author introduce himself in all his glory:

Dr Geoffrey Roper is an international bibliographical and library consultant, working with the Institute for the Study of Muslim Civilisations in London and other scholarly bodies. Educated at the University of Durham and the American University in Cairo, he was from 1982 to 2003 head of the Islamic Bibliography Unit at the University of Cambridge and editor of Index Islamicus, the major current comprehensive bibliography and search tool for publications on all aspects of Islam and the Muslim world. He has also been editor of Al-Furqan Foundation’s World Survey of Islamic Manuscripts, Chairman of the Middle East Libraries Committee (MELCOM-UK) and contributor to various reference works. He has researched, written and lectured extensively on bibliography and the history of printing and publishing in the Muslim world, and has curated exhibitions on the subject at Cambridge University Library and the Gutenberg Museum in Mainz. He is currently an Associate Editor of the forthcoming Oxford Companion to the Book. For a comprehensive list of his publications, see below at the end of this article.

We now turn to Gutenberg and the history of printing:

The 15th-century German craftsman Johannes Gutenberg of Mainz is often credited with inventing the art and craft of printing. There is no doubt that this brought about a tremendous revolution in human communication and accumulation of knowledge, but was it really “invented” in 15th-century Europe?

The straight answer to Roper’s question is no, and once again I shall be returning to it again shortly. Roper gives he own answer to his question.

Gutenberg does seem to have been the first to devise a printing press, but printing itself, that is, making multiple copies of a text by transferring it from one raised surface to other portable surfaces (especially paper) is much older. The Chinese were doing it as early as the 4th century, and the oldest dated printed text known to us is from 868: the Diamond Sutra, a Chinese translation of a Buddhist text now preserved in the British Library

This answer is totally correct as far as it goes, except that the earliest examples of Chinese printing date back to the second century CE. So far so good but what about the Muslims? Roper now turns to them:

What is much less well known is that, little more than 100 years later, Arab Muslims were also printing texts, including passages from the Qur’an.

This I have to admit was new to me and an interesting addition to my knowledge of the history of printing. It should be pointed out, because it is somewhat ambiguous, that 100 years later is one hundred years after the printing of the Diamond Sutra and not after the fourth century. What follows, is some details of the history of Arabic printing and the inevitable question as to whether it influenced the introduction of printing into Europe; for which Roper admits there is no evidence before he closes with the conclusion already stated in the title:

What is not in doubt is that Muslims were practising the craft of printing for some five centuries before Gutenberg.

I wouldn’t deny this statement so what’s my beef? Why am I writing this post and what is the author’s fundamental flaw that I alluded to earlier?

Our supposed expert on printing is, in his article, confounding and confusing two different technologies, block printing, and movable type printing, which whilst related are not the same at all. Worse than this, his claim that the Muslims got there five hundred before Gutenberg is based on this confusion.

His article is about the history of block printing, that is when a relief is cut out of a block of material, wood or as many of us know from our childhood even the humble potato, is smeared with some form of pigment, paint or ink, then pressed on to an absorbent surface, fabric, paper or whatever, to produce a reverse image of the cut out relief. All of the printing that Roper describes is block printing including the Diamond Sutra, the earliest known example of a so-called block book. This technique has its origins in the shapes pressed into unfired clay using seals and stamps, going back thousands of years, and as a form of printing appears to have first appeared in China around the beginning of the Common Era.

What Gutenberg is credited with having introduced into Europe is movable type printing, a different beast altogether. In moving type printing the texts to be printed are composed of individual letters carved or cast in reverse, which can be then taken apart and reused in different combination multiple times.

This technology was not first invented by Gutenberg but had been invented several times before. The Chinese used both wood and ceramic movable type in the eleventh century CE, the latter replacing the former as it proved problematic. The Chinese were also using bronze metallic movable type by the twelfth century CE, using it to print money and documents. There is evidence that they also used it to print books but the oldest surviving Chinese book printed using movable type post dates Gutenberg. The Koreans are known to have printed books using bronze movable type in the thirteenth century CE but the oldest surviving Korean printed book dates from the fourteenth century, i.e. before Gutenberg.

This brief sketch of the history of printing throws up some interesting questions. If block printing dates back to the first century CE, or possibly even earlier, why did this technique only appear in Europe in the fifteenth century around the same time as Gutenberg invented his version of movable type printing? I know of no reasonable answer to this question.

Did Gutenberg or the other Europeans who were experimenting with movable type around the same time have knowledge of the Asian movable type? Was there a technology transfer? This question has been thoroughly investigated from all sides by many scholars and absolutely no evidence of a technology transfer has been found leading to the tentative conclusion that Gutenberg’s was an independent invention. It should also be pointed out that Gutenberg seems to have been the first to use movable type in a printing press and also to have been the inventor of an oil based ink that greatly facilitated the process of printing on paper.

Another interesting question that relates directly to Roper’s article is, if the Muslims acquired the technique of paper making (along with many other things) from the Chinese, which Roper mentions in his article, and which they passed onto the Europeans through Spain, why didn’t they also acquire the technique of movable type printing? This is a question that has also been investigated by many scholars without reaching any really convincing conclusions.

I find Roper’s article both disingenuous and disturbing. For people not knowledgeable in the various types of printing and their histories it would appear that Roper has uncovered another example of Europeans claiming credit for an invention that by rights belongs to the Muslims of the Arabic Empire. However this is not the case and I personally think that somebody as qualified as Roper should have made this clear in his article.


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Filed under History of Technology

Made in Nürnberg

In the period from roughly 1550 and 1650 Nürnberg was the leading centre in Europe, and thus probably the world, for the manufacture of scientific instruments. It is historically interesting to look at how this town in the middle of Europe came to acquire this status and also to take a brief look at some of the more famous of the Nürnberger instrument makers from this ‘golden’ period.

Like many European towns and cities, Nürnberg, as an entity, began to emerge at the beginning of the High Middle Ages, probably around the year 1000 CE. Like many such settlements it was initially not much more than a fortified hill top at a crossroads. The first record of the name is 1050 CE as nuorenberc, which later evolved into Nuremberg, the name by which it is still known in English. This name is the subject of a rare German bad pun; the Germans don’t really go in for puns. According to folk etymology the name was originally ‘Nur einem Berg’, which translates as ‘just a hill’. The geographical position of Nürnberg played an important role in its development. If you take an outline map of Europe and draw a straight line from Kiel, in Northern Germany, to Northern Italy and a second one from Paris to Prague, the point where they cross is Nürnberg. This led to Nürnberg becoming a major European trading hub in the medieval period; importing wares from the Northern Italian trading cities and then distributing them throughout Europe.

Germany didn’t exist as a country in the Middle Ages but was a loose conglomerate of large and small states interconnected through a network of feudal obligations and vaguely held together in the so-called Holy Roman Empire, which as somebody once quipped was neither holy nor Roman nor an empire. Within this patchwork of large and small Germanic states Nürnberg was one of the so-called Free Imperial Cities, small independent city-states, which only owed feudal allegiance to the Holy Roman Emperor. From 1105 CE Nürnberg was ruled by a hereditary Burggraf, a title that translates as Lord of the castle. From 1192 till 1427 the Burggrafen of Nürnberg came from the Hohenzollern family, who would go on to play a significant role in German history. In 1427 the rich traders of Nürnberg, of whom more shortly, bought the Burggraf rights from the Hohenzollern and from then on until 1806, when Nürnberg became part of Bavaria, the city was ruled by the town council. Although dominated by the rich trader families the town council was surprisingly democratic with three groups of councillors being appointed/elected from the three tiers of citizenry at regular intervals. During the Renaissance Nürnberg, like one of its major trading partners Venice, called itself a republic.

The Holy Roman Emperor granted the city of Nürnberg special tax privileges, which combined with its favourable geographical position and the large Europe wide demand for the spices that came into Europe through the Northern Italian trading cities meant that the Nürnberg traders became very, very wealthy. This led to them looking for new opportunities to invest their surplus profits. The High Middle Ages saw a steeply rising demand for metals (gold, silver, copper, lead, iron) and with it an expansion of the metal ore mining industry. The major ore deposits, and thus the mines, were situated in the eastern part of Middle Europe, Eastern Germany, Hungary, Rumania, Austria etc. Realising that it was an expanding business with a future the Nürnberg traders began investing in the metal ore mines and soon controlled a large part of this industry. At first content just to sell the ore they soon realised that they could make more profit if they smelted the ore themselves and so built their own smelters and began selling refined metal. It did not take long before the artisans of Nürnberg began to work the metal themselves producing finished metal objects for sale. By the fifteenth century Nürnberg had become one of the major metal working centres of Europe producing quite literally everything that could be made from metal from pins and needles to suits of armour. A sign of this development is that the first mechanical wire drawing machine was developed in Nürnberg. The Nürnberg guilds were incredibly well organised with single families responsible for the production of one object or group of objects. When Karl V (Holly Roman Emperor 1519–1556) ordered 5000 suits of armour from Nürnberg, one group of families was responsible for the leg plates, another for the breast plates and so on. Highly organised piecework.

Nürnberg as depicted in the Nuremberg Chronicles 1493

Nürnberg as depicted in the Nuremberg Chronicles 1493

Of course many scientific instruments are made of metal, mostly brass, and so Nürnberg in its all inclusiveness became a major centre for the manufacture of all types of scientific instruments. In fact it became the leading European centre for this work and thus, most probably, the leading world centre in the fifteenth and sixteenth centuries. We have two important historical attestations of Nürnberg’s supremacy in this area. The philosopher Nicholas of Cusa (Cusanus) (1401–1464) was very interested in astronomy and he purchased a celestial globe and other astronomical instruments from Nürnberg and this can still be viewed in the Cusanus Museum in his birthplace Kues. In 1470 when Johannes Regiomontanus set out to reform and modernise astronomy he moved from Budapest to Nürnberg because, as he tells us in a letter, Nürnberg had a good communications network through which he could communicate with other astronomers and because the best astronomical instruments were manufactured in Nürnberg. The communications network was an essential element of any Renaissance trading city and Nürnberg’s was second only to that of Venice.

By 1500 Nürnberg was the second biggest German city with a population of around 40 000, half of which lived inside the city walls and the other half in the surrounding villages, which belonged to the city. It was one of the richest cities in the whole of Europe and enjoyed a high level of culture, investing both in representative architecture and the arts, with many of the leading German Renaissance artists fulfilling commissions for the rich Nürnberg traders, known locally as the Patrizier; most famously Albrecht Dürer. Interesting in our context, Dürer’s maths book contained the first printed instructions in German of how to design and construct sundials. The first half of the sixteenth century was the golden age of scientific instrument production in Nürnberg with many of the leading instrument makers selling their wares throughout Europe, where they can still be found in museums in many different countries. In what follows I shall give brief sketches of a couple of the more well known of these craftsmen.

Nürnberg was famous for it’s portable sundials with family dynasties producing high quality products over three, four or even five generations. At the beginning of the sixteenth century the most significant sundial maker was Erhard Etzlaub (ca. 1460–1532) who like many other Nürnberger instrument makers was as much as a scholar as an artisan. As a cartographer he produced the first map of the Nürnberg region. He followed this with the so-called Rome pilgrimage map displaying the routes to Rome for the Holy Year of 1500, which famously Copernicus also attended. This map plays an important role in the history of modern cartography because it’s the first map with a scale, enabling the pilgrim to plan his daily journeys.

Etzlaub's Rome Pilgrim Map Source: Wikimedia Commons

Etzlaub’s Rome Pilgrim Map
Source: Wikimedia Commons

Etzlaub also constructed a map on the cover of one of his compasses in 1511 that is drawn in a projection that comes close to the Mercator projection. Etzlaub was a member of the so-called Pirckheimer Circle. A group of like minded proponents of the mathematical sciences centred around Willbald Pirckheimer, soldier, politician humanist scholar and translator from Greek into Latin of Ptolemaeus’ Geographia; a translation that became a standard work.

Willibald Pirckheimer, porträtiert von Albrecht Dürer (1503) Source: Wikimedia Commons

Willibald Pirckheimer, porträtiert von Albrecht Dürer (1503)
Source: Wikimedia Commons

This group of mathematical scholars demonstrated their interest in the mathematical sciences and in the construction of complex instruments in the highly complex sundial that they painted on the side of the Lorenzkirche in 1502, which also displays the time according to the Great Nürnberger Clock:

Lorenzkirche Sundial Source: Astronomie in Nürnberg

Lorenzkirche Sundial
Source: Astronomie in Nürnberg

And the clock on the Frauenkirche constructed in 1506:

Frauenkirche Clock

Frauenkirche Clock

The gold and blue ball above the clock dial displays the phases of the moon and is still accurate today.

Another member of the Pirckheimer Circle was Johannes Schöner(1477–1547), addressee of Rheticus’ Naratio Prima, the first published account of Copernicus’ heliocentrism.

Johannes Schöner Source: Wikimedia Commons

Johannes Schöner
Source: Wikimedia Commons

Schöner was the first producer of serial production printed globes both terrestrial and celestial. He also wrote, printed and published pamphlets on the design and manufacture of various scientific instruments. Schöner was Europe’s leading globe maker whose globes set standards for globe making, which influenced the manufacture of globes down to the nineteenth century.

Schöner Celestial Globe 1535 Source: Science Museum London

Schöner Celestial Globe 1535
Source: Science Museum London

Also a member of the Pirckheimer Circle and a close friend of Schöner’s was Georg Hartman (1489–1564).

Georg Hartmann Source: Astronomie in Nürnberg

Georg Hartmann
Source: Astronomie in Nürnberg

Hartmann like Schöner was a globe maker although none of his globes have survived. He was also one of the leading sundial makers of his generation and his complex and beautiful dials can still be found in many museums.

Hartmann Bowl Sundial Source: Wikimedia Commons

Hartmann Bowl Sundial
Source: Wikimedia Commons

In the early sixteenth century Nürnberg was the main European centre for the production of astrolabes and here Hartmann played a leading role. As far as can be ascertained Hartmann was the first person to produce astrolabes in series.

Hartmann Astrolabe Yale Source: Wikimedia Commons

Hartmann Astrolabe Yale
Source: Wikimedia Commons

Previously all astrolabes were produced as single pieces, Hartmann, however, produced series of identical astrolabes, probably employing other craftsmen to produce the individual parts according to a pre-described plan and them assembling them in his workshop. As a young man Hartmann had spent several years living in Italy where he was friends with Copernicus’ brother Andreas. As a scholar Hartmann was the first to investigate magnetic inclination or dip. However his studies were never published and so the credit for this discovery went to the English mariner Robert Norman.

Handmade metal instruments were, of course, very expensive and could in reality only be purchased by the wealthy, who often bought them as ornaments of status symbols rather than to be used. To make scientific instruments available to those with less money both Schöner and Hartmann produced paper instruments. These consisted of the scales and tables, normally found engraved on the metal instruments, printed accurately on paper, which the user could then paste onto a wooden background and so construct a cheap but functioning instrument.

Paper and Wood Astrolabe Hartmann Source: MHS Oxford

Paper and Wood Astrolabe Hartmann
Source: MHS Oxford

A later instrument maker was Christian Heiden (1526–1576) who like Schöner was professor for mathematics on the Egidiengymnasium in Nürnberg, Germany’s first gymnasium (similar to a grammar school). He made a wide range of instruments but was especially well known for his elaborate and elegant sundials, as much works of art as scientific instruments these were much prized amongst the rich and powerful and could be found on many a German court.

Column Sundial by Christian Heyden Source: Museumslandschaft Hessen-Kassel

Column Sundial by Christian Heyden
Source: Museumslandschaft Hessen-Kassel

This is of course only a very, very small sample of the Nürnberger instrument makers, the history pages of the Astronomie in Nürnberg website, created and maintained by Dr Hans Gaab, lists 44 globe makers, 38 astronomical instrument makers and more than 100 sundial makers between the fifteenth and nineteenth centuries; with the greatest concentration in the sixteenth century. Nürnberg was known throughout Europe for the quality and the accuracy of its scientific instruments and examples of the Nürnberger handwork can be found in museums in many countries, even outside of Europe.


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