Category Archives: History of science

Bringing the heavens down to earth

The Frisian Protestant pastor and amateur astronomer, David Fabricius, was beaten to death by one of his parishioners on 7 May 1617. Because he corresponded with both Tycho Brahe and Johannes Kepler and was quite a significant figure in Early Modern astronomy the Society for the History of Astronomy had a short post on Facebook commemorating his death on last Sunday, which contained the following claim:

David Fabricius was, following Galileo’s lead, one of the early users of the telescope in astronomy[1]

This claim contains two factual errors. The first is that it was Johannes, David’s son, who introduced the telescope into the Fabricius household and not David, although David soon joined his son in his telescopic observations. I’ll explain further later.

The Fabricii, father and son, remain largely unknown to the world at large but a monument to them both was erected in the churchyard in Osteel, where David had been village pastor, in 1895.

The second error is more serious because it indirectly perpetuates a widespread myth concerning the introduction of the telescope into astronomy and Galileo’s role in it. There is a popular perception that Galileo, and only Galileo, had the genius, the wit, the vision to realise that the newly invented telescope could be used as an astronomical instrument and that he singlehandedly pioneered this new discipline, telescopic astronomy. This is of course complete rubbish and seriously distorts the early history of the telescope in astronomy and does a major disservice to all of the others who contributed to that early history. I will admit to having done a small fist pump when I read the following in John Heilbron’s Galileo biography:

The transformation of the Dutch gadget into an instrument powerful to discover novelties in the heavens did not require a Galileo. His unique strength lay in interpreting what he saw.[2]

That the telescope could be used as an astronomical instrument was recognised during its very first public demonstration by its inventor, the German/Dutch spectacle maker Hans Lipperhey, which took place at the court of Prince Maurice of Nassau in Den Haag during the Dutch-Spanish Peace Conference on an unknown day between 25 and 29 September 1608. We have a detailed account of this demonstration from a French flyer or newsletter describing the first visit of the Ambassador of Siam to Europe, the Ambassador being present at the demonstration. Through this flyer the news of the new invention spread rapidly throughout Europe. Amongst the other descriptions of the wonderful abilities of this “…device by means of which all things at a very great distance can be seen as if they were nearby, by looking through glasses…” we can read the following:

The said glasses are very useful at sieges & in similar affairs, because one can distinguish from a mile’s distance & beyond several objects very well, as if they are near & even the stars which normally are not visible for us, because of the scanty proportion and feeble sight of our eyes, can be seen with this instrument. [my emphasis]

The first astronomer to build and use a telescope as an astronomical instrument was Thomas Harriot, who drew a sketch of the moon using a telescope on 26 July 1609 before Galileo even had a telescope.

Thomas Harriot’s 1609 telescopic sketch of the moon

This of course raises the question where Harriot obtained his knowledge of this instrument. In the early phase of the telescopes existence it became a common habit to present heads of state and other worthies telescopes as presents. In England James I (VI of Scotland) was presented with one at the end of an elaborate masque created for the occasion by Ben Jonson, the Renaissance playwright. The telescope was obtained from the United Provinces through the offices of Cornelis Drebbel, the Dutch inventor and scholar, who was employed at James’ court. This telescope was probably Harriot’s, who enjoyed good connections to court circles, introduction to the instrument.

Portrait often claimed to be Thomas Harriot (1602), which hangs in Oriel College, Oxford. Source: Wikimedia Commons

Harriot did not observe alone. In London he observed together with his instrument maker Christopher Tooke in London, whilst Harriot’s pupil the landowner and MP, Sir William Lower observed in Wales, together with his neighbour John Prydderch, with a telescope made by Harriot and Tooke. Each pair took turns in observing comparing their results and then Harriot and Lower compared results by letter. This meant that they could be reasonably certain that what they had observed was real and not some optical artefacts produced by the poor quality of the lenses they were using. So here we have four telescopic astronomical observers independent of Galileo’s activities.

In Franconia Simon Marius also built and used telescopes in 1609, at the time unaware of the similar activities of Galileo in Padua. As I have written in another blog post Marius discovered the four largest moons of Jupiter just one day later and independently of Galileo. Marius also made the first telescopic observations of the Andromeda Nebula, significant because the Andromeda Nebula would later become the first galaxy to be recognised as a galaxy outside of our galaxy.

Simon Marius frontispiece from his Mundus Jovialis

Another telescopic pioneer in Southern Germany was the Jesuit astronomer in Ingolstadt, Christoph Scheiner, who famously became embroiled in a dispute with Galileo over who had first observed sunspots with a telescope and what exactly they were.

Christoph Scheinet (artist unknown)

The dispute was rather pointless, as Harriot had actually observed sunspots earlier than both of them and Johannes Fabricius, to whom we will turn next, had already published a report on his sunspot observations unknown to the two adversaries. Christoph Scheiner and his assistant, another Jesuit astronomer, Johann Baptist Cysat, would go on to make several important contributions to telescopic astronomy.

Johann Baptist Cysat, holding a Jacob’s staff

Johannes Fabricius brought his telescope home from the University of Leiden, where he had almost certainly learnt of this instrument through the lectures of Rudolph Snel van Royan, professor of mathematics and father of the better know Willibrord Snel of Snell’s law of refraction fame. Rudolph Snel van Royan was probably the first university professor to lecture on the telescope as a scientific instrument already in 1610.

Rudolph Snel van Royan
Source: Wikimedia Commons

It is also known that Cort Aslakssøn and Christian Longomontanus acquired lenses and built their own telescopes in the first couple of years of telescopic astronomy in Copenhagen, but unfortunately I haven’t, until now, been able to find any more details of activities in this direction. If any of my readers could direct me to any literature on the subject I would be very grateful.

Christian Severin known as Longomontanus

Turning to Italy we find the astronomers on the Collegio Romano under the watchful eye of Christoph Clavius making telescopic astronomical observations before Galileo published his Sidereus Nuncius in 1610, using a Dutch telescope sent to Odo van Maelcote by one of his earlier students Peter Scholier. Grégoire de Saint-Vincent would later claim that he and Odo van Maelcote were probably the very first astronomers to observe Saturn using a telescope. It was the astronomers of the Collegio Romano, most notably Giovanni Paolo Lembo and Christoph Grienberger, who would then go on to provide the very necessary independent confirmation of the discoveries that Galileo had published in the Sidereus Nuncius.

As can be seen Galileo was anything but the singlehanded pioneer of telescopic astronomy in those early months and years of the discipline. What is interesting is that those working within the discipline were not isolated lone warriors but a linked network, who exchanged letter and publications with each other.

Some of the connections that existed between the early telescopic astronomers are listed here: Harriot had corresponded extensively with Kepler and was very well informed about what Tycho and the other continental astronomers were up to. David Fabricius corresponded with Kepler and Tycho and even visited Tycho in Prague but unfortunately didn’t meet Kepler on his visit. Johannes would later take up correspondence with Kepler. Tycho corresponded with Magini in Bologna who passed on his news to both Galileo and Clavius. Clavius was also very well informed of all that was going on in European astronomy by the Jesuit network. Almost all of the Jesuit astronomers were students of his. Marius corresponded with Kepler, who published many of his astronomical discoveries before he did, and with David Fabricius, whom he had got to know when he visited Tycho in Prague to study astronomy. Longomontanus had earlier been Tycho’s chief assistant and corresponded with Kepler after he left Prague to return to Copenhagen. Interestingly another of Tycho’s assistants, Johannes Eriksen, visited both David Fabricius in Friesland and Thomas Harriot in London on the same journey.

What we have here is not Galileo Galilei as singlehanded pioneer of telescopic astronomy but a loosely knit European community of telescopic astronomers who all recognised and utilised the potential of this new instrument shortly after it appeared. They would soon be joined by others, in this case mostly motivated by Galileo’s Sidereus Nuncius, a few of them even supplied with telescopes out of Galileo’s own workshop. However what is very important to note is that although Galileo was without doubt the best telescopic observer of that first generation and certainly won the publication race, all of the discoveries that he made were also made independently and contemporaneously by others, so nothing would have been lost if he had never taken an interest in the spyglass from Holland.






[1] Because I pointed out the errors contained in this claim in a comment, it has now been removed from the Facebook post!

[2] J. L. Heilbron, Galileo, OUP, 2010, p. 151


Filed under History of Astronomy, History of Optics, History of science, Uncategorized

One line to rule them all

A standard concept in the modern politico-military terminology is that of mission creep. This describes the, in the last sixty or seventy years often observed, phenomenon of a military intervention by a dominant power that starts with a so-called police action with a couple of hundred combatants and then within a couple of years grows to a full scale military operation involving thousands of troops and the expenditure of sums of money with an eye watering large number of zeros at the end. Famous examples of mission creep were the Americans in Viet Nam and the Russians in Afghanistan. In fact since the Second World War the American have become world champions in mission creep.

As a historian I, and I strongly suspect virtually all of my historian colleagues, experience a form of mission creep in every field of study to which I turn my attention. In fact the progress of my entire career as a historian of science has been one massive example of mission creep. It all started, at the age of sixteen, when I first learned that Isaac Newton was the (co)discoverer/inventor[1] of the calculus that I so loved at school. (Yes, I know that makes me sound a little bit strange but there’s no accounting for taste). This of course set me off on the trail of the whole history of mathematics, but that is not what I want to talk about here; let us stick with Newton. At some point I started to wonder why Newton, whom I saw as very much the theoretical mathematician and physicist, should have invented a telescope. This set me on the trail of the entire history of the telescope and because the telescope is an optical instrument, with time, the history of optics, not just in the early modern period but backwards through time into the European Middle Ages, the Islamic Empire and Antiquity. Of course Newton is most well known as physicist and astronomer and at some point I started investigating the pre-history of his work in astronomy. This eventually led me back to the Renaissance astronomers, not just Copernicus but all those whose work provided the foundations for Copernicus’s own work.

At some point it became very clear to me that to talk of Renaissance astronomers was in some sense a misnomer because those who pursued the study of astronomy in this time did so within a discipline that encompassed not just astronomy but also astrology, cartography (with a large chunk of geography and history in the mix), navigation, surveying, geodesy as well as the mathematical knowledge necessary to do all of these things. These were not separate disciplines as we see them now but different facets of one discipline. Over the years my studies have expanded to cover all of these facets and one into which I have delved very deeply is the history of cartography with the associated history of surveying. All of this is a rather longwinded explanation of why I have been reading Charles Withers’ new book Zero Degrees[2]


This book describes the history of how the Greenwich Meridian became the Prime Meridian.

A brief explanation for those who are not really clear what a meridian is; a meridian (or line of longitude) is any ‘straight’ line on the globe of the of the earth connecting the North Pole with the South Pole, where here straight means taking the shortest path between the two poles, as a meridian is by nature curved because it lies on the surface of the globe. Meridians are by their very nature arbitrary, abstract and non-real. We can chose to put a meridian wherever we like, they are an artificial construct and not naturally given. The Prime Meridian is a singular, unique, universally accepted meridian from which all other meridians (lines of longitude) are measured. The recognition of the necessity for a Prime Meridian is a fairly recent one in human history and Withers’ book deals with the history of the period between that recognition in the Early Modern Period to the realisation of a Prime Meridian at the beginning of the twentieth century.

The first thing that Withers made me aware of is that a meridian is not a singular object but one that has at least four separate functions and at least two different realisations. Meridians are used for navigation, for time determination, for cartography and for astronomy. The latter is because astronomers project our latitude and longitude coordinate system out into space in order to map the heavens. Nothing says that one has to use the same meridians for each of these activities and for much of the period of history covered by Withers people didn’t.

On the realisation of meridians Withers distinguishes two geographical and observed. The majority of meridians in use before the late seventeenth century were geographical. What does this mean? It meant that somebody simply said that they make their measurements or calculations from an imaginary line, the meridian, through some given geographical point on the surface of the earth. Ptolemaeus to whom we own our longitude and latitude coordinate system, although he had predecessors in antiquity, used the Azores as his zero meridian although he didn’t know with any real accuracy where exactly the Azores lay. Also the Azores is a scattered island group and he doesn’t specify exactly where within this island group his zero meridian ran. We have a lovely example of the confusion caused by this inaccuracy. On 4 May 1493 Pope Alexander VI issued the papal bull Inter caetera, which granted the Crowns of Castile and Aragon all the lands to the west and south of a meridian 100 leagues and south of the Azores or the Cape Verde islands.

This led to a whole series of treaties and papal bulls carving up the globe between Spain (Castile and Aragon) and Portugal. The 1494 Treaty of Tordesillas moved the line to a meridian 370 leagues west of the Portuguese Cape Verde islands now explicitly giving Portugal all new discoveries east of this meridian. I’m not going to go into all the gory details but this led to all sorts of problems because nobody actually knew where exactly this meridian or its anti-meridian on the other side of the globe lay. Ownership disputes in the Pacific between Spain and Portugal were pre-programmed. These are classical examples of geographical meridians.

The Cantino planisphere of 1502 shows the line of the Treaty of Tordesillas.
Source: Wikimedia Commons

The first observed meridian in the Early Modern Period was the Paris Meridian surveyed by Jean-Félix Picard in the 1660s. Such meridians are called observed because their exact position on the globe is determined astronomically using a transit telescope.

In the Early Modern Period there was no consensus as to which meridian should be used for which purpose and on the whole each country used its own zero meridian. I fact it was not unusual for several different zero meridians to be used for different purposes or even the same purpose, with one country. For geographers, cartographers and navigators crossing borders chaos ruled. The awareness that a single Prime Meridian would be beneficial for all already existed in the seventeenth century but it wasn’t until the nineteenth century that serious moves were made to solve the problem.

The discussion were long and very complicated and involved scientific, political and pragmatic considerations, which often clashed with each other. On the political level nationalism, of course, raised its ugly head. Surprisingly, at least for me, there was also a very heated discussion as to whether the Prime Meridian should be a geographical or an observed meridian. I personally can discern no reasons in favour of a geographical Prime Meridian but various participants in the discussions could. Another problem was one or more Prime Meridians? Separate ones for cartography, navigation, astronomy and time determination.

Withers deals with all of these topics in great detail and very lucidly in his excellent summery of all of the discussions leading up to the International Meridian Conference in Washington in 1884, which forms the climax of his book.

The delegates to the International Meridian Conference in Washington in 1884
Source: Wikimedia Commons

This is a truly fascinating piece of the history of science and in Withers it has found a more than worthy narrator and I recommend his book whole-heartedly for anybody who might be interested in the topic. Very important is his penultimate chapter Washington’s Afterlife. Every year in October people in the Internet announce that on this day in 1884 (I can’t be bothered to look up the exact date) the Greenwich Meridian became the world’s Prime Meridian and every year my #histsci soul sisterTM Rebekah ‘Becky’ Higgitt (who played a significant role in the genesis of Withers’ book, as can be read in the acknowledgements) announces no it didn’t, the resolutions reached in Washington were non-binding. In fact the acceptance of Greenwich as the Prime Meridian took quite some time after the Washington Conference, some even accepting it initial only for some but not all the four functions sketched above. France, whose Paris Meridian was the main contender against Greenwich, only finally accepted Greenwich as the Prime Meridian in 1912.

I do have a couple of minor quibbles about Withers’ book. In the preface he outlines the structure of the book saying what takes place in each section. He repeats this in greater detail in the introduction. Then he starts each chapter with a synopsis of the chapter’s contents, often repeating what he has already said in the introduction, and closes the chapter with a summary of its contents. It was for this reader a little bit too much repetition. My second quibble concerns the illustrations and tables of which there are a fairly large number in the book. These are all basically black and white but are in fact printed black on a sort of pastel grey. I assume that the book designer thinks this makes them somehow artistically more attractive but I personally found that it makes it more difficult to determine the details, particularly on the many maps that are reproduced. Whatever I wouldn’t let these rather personal minor points interfere with my genuine whole-hearted recommendation.

[1] Chose the word that best fits your personal philosophy of mathematics

[2] Charles W. J. Withers, Zero Degrees: Geographies of the Prime Meridian, Harvard University Press, Cambridge Massachusetts, London England, 2017

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Filed under History of Cartography, History of Navigation, History of science

The problem with superlatives

I have on several occasions in the past written about the problems of the use of certain superlative terms in presentations of the history of science, in particular in popular ones, such as first, father of, founder of and the greatest, as they only lead to a distortion of what really happens in the historical evolution of the scientific disciplines.

The term the greatest reared its ugly head again last week in the form of a tweet by Professor Frank McDonough (@FXMC1957) (historian).

18 April 1955. Albert Einstein (aged 76) died. He was arguably the greatest scientist who ever lived.

If Einstein is arguably the greatest scientist who ever lived, it raises the question, who his competitors might possibly be for this obviously coveted accolade. A typical discussion would almost certainly immediately throw up the names Isaac Newton, Galileo Galilei and Archimedes, going backwards in time. This almost canonical list, including of course Einstein, throws up a whole series of problems.

For me personally the first problem is that the list almost never includes Johannes Kepler, although any serious and unbiased comparison of their achievements, and they were contemporaries, would show quite clearly that Kepler actually contributed significantly more to the evolution of the sciences than Galileo. However for various reasons Kepler lacks the historical nimbus that Galileo has acquired down the centuries.

The second problem is that one is not actually comparing like with like. The mathematician and maths historian Eric Temple bell, whose book Men of Mathematics ignited my interest in the history of mathematics as a teenager, asked the question, “who was the greatest mathematician of all times?” He came up with a list of three names Archimedes, Isaac Newton and Johann Carl Friedrich Gauss (Gauss was also an extraordinary polymath who made important and significant contributions to astronomy, geodesy, cartography, optics, mechanics and, and…, so why isn’t he ever on the greatest scientist lists?). Bell then argued that it was impossible to say, which of the three was the greatest in terms of their mathematical achievements but Archimedes was operating on a much smaller basis of pre-existing knowledge so his achievements should be judged as greater.

Bell’s argument has a certain historical validity and makes us very much aware of the problems and dangers of trying to compare the achievements of practitioners of science across the depths of time. Galileo’s achievements can only be judged against the background of the late sixteenth century and early seventeenth, Newton’s against the background of the late seventeenth, when the situation in physics and astronomy was very different to that at the beginning of the century. Both of them are separated by a vast gulf in time from Archimedes and although the gap between Newton and Einstein is smaller the difference in background situations is immense. In the end we can only really compare a given scientist with his contemporaries.

Another problem that the canonical list immediately calls to attention is that all four of our candidates are basically mathematical physicists, which displays a strong bias against all the other scientific disciplines. This bias has existed for a very long time and is one of the things that current historians of science try to combat. For a very long time the history of science was seen principally as the history of the exact sciences i.e. mathematics, astronomy and physics. All other disciplines tended to be treaded as somehow secondary. Also the philosophy of science tended to be defined as the philosophy of physics. Returning to our list and its built in bias, not a few life scientists on reading it would say, quite correctly, what about Charles Darwin? Is not the discovery of the principle of evolution equal or even superior to anything discovered by the physicists or the astronomers? Having opened that can of worms somebody might put in a vote for Watson and Crick, after all Matthew Cobb’s excellent book on the discovery of the structure of DNA is titled, Life’s Greatest Secret! Oh dear that nasty superlative has crept in again.

At this point the chemists, who always get left out of such discussions, could well chime in with claims for Joseph Priestley, Antoine Lavoisier, Humphry Davy, Justus von Liebig and of course Marie Curie (after all she got two Nobels whereas Albert only got one!). Having brought up Humphry Davy a self taught, brilliant scientist, one should immediately think of his famous assistant and successor, the equally self taught, Michael Faraday; now there is a serious candidate for the greatest.

Another problem with this form of historical deification of scientists, the greatest, is that it fosters and perpetuates the myth of the lone genius. Returning to Einstein, undoubtedly an incredibly productive physicist, who contributed substantially to two of the biggest fields in twentieth century physics, his work built on the work of many, many others and contributions were made to the development of his own major discoveries, Relativity and Quantum Theory, by a fairly large group of other mathematicians, physicists and astronomers. No scientist exists in a vacuum but is part of a collective endeavour pushing forward the boundaries of their discipline. Historians of science should not concern themselves with the irrelevant and uninformative question, who’s the greatest, but should rather try to embed individuals into the context in which they did their work and the nexus of others who contributed to that work and those effected by it in their own efforts. Context is everything could well be the motto of this blog.


Filed under History of science, Myths of Science

Measure for measure

The Brexit vote in the UK has produced a bizarre collection of desires of those Leavers eager to escape the poisonous grasp of the Brussels’ bureaucrats. At the top of their list is a return of the death penalty, a piece of errant stupidity that I shall leave largely uncommented here. Not far behind is the wish to abandon the metric system and to return to selling fruit and vegetables in pounds and ounces. This is particularly strange for a number of reasons. Firstly the UK went metric in 1965, six years before it joined the EU. Secondly EU regulations actually allows countries to use other systems of weights and measures parallel to the metric system, so there is nothing in EU law stopping greengrocers selling you a pound of carrots or bananas. Thirdly the country having gone metric in 1965, anybody in the UK under the age of about fifty is going to have a very hard time knowing what exactly pounds and ounces are.

Most readers of this blog will have now gathered that I have spent more than half my life living in Germany. Germany is of course one of the founding states of the EU and as such has been part of it from the very beginning in 1957. The various states that now constitute Germany also went metric at various points in the nineteenth century, the earliest in 1806-15, and the latest in 1868. However the Germans are a very pragmatic folk and I can and do buy my vegetables on the market place in Erlangen in pounds and half pounds. The Germans like most Europeans used variation of the predecessors to the so-called Imperial system of weights and measures and simple re-designated the pound (Pfund in German) to be half a kilo. The Imperial pound is actually approximately 454 grams and for practical purposes when buying potatoes or apples the 46-gram difference if negligible. Apparently the British are either too stupid or too inflexible to adopt such a pragmatic solution.

At the beginning of the month Tory dingbat and wanna be journalist Simon Heffer wrote an article in The Telegraph with the glorious title, Now that we are to be a sovereign nation again, we must bring back imperial units. I haven’t actually read it because one has to register in order to do so and I would rather drink bleach than register with the Torygraph. I shall also not link to the offending article, as it will only encourage them. Heffer charges into the fray thus:

But I know from my postbag that there is another infliction from the decades of our EU membership that many would like to be shot of, and that was the imposition of the metric system on large parts of our life. 

Consumer resistance ensured that our beer is still served in pints (though not in half-pint and pint bottles when bought in supermarkets: brewers please note), and that our signposts are still marked in miles.

As pointed out above it was not the EU who imposed the metric system on British lives but the British government before the UK joined the EU. According to EU regulations you can serve drinks in any quantities you like just as long as the glasses are calibrated, so keeping the traditional pint glasses and mugs in British pubs was never a problem. Alcohol is sold in Germany in a bewildering range of different size glasses depending on the local traditions. My beer drinking German friends (the Germans invented the stuff, you know) particularly like pints of beer because they say that they contain a mouthful more beer that a half litre glass. Sadly many bars in Franconia have gone over to selling beer in 0.4litre glasses to increase their profits, but I digress.

UK signposts are still marked in miles because the government could not afford the cost of replacing all of them when the UK went metric. Expediency not national pride was the motivation here.

Just before Heffer’s diatribe disappears behind the registration wall he spouts the following:

But we have been forced on to the Celsius temperature scale, which is less precise than Fahrenheit

When I read this statement I went back to check if the article had been published on 1 April, it hadn’t! Is the international scientific community aware of the fact that they have been conned into using an inaccurate temperature scale? (I know that scientist actually use the Kelvin temperature scale but it’s the same as the Celsius scale with a different zero point, so I assume by Heffer’s logic(!) it suffers from the same inaccuracy). Will all of those zillions of experiments and research programmes carried out using the Celsius/Kelvin scale have to be repeated with the accurate Fahrenheit scale? Does Simon Heffer actually get paid for writing this crap?


Anders Celcius Portrait by Olof Arenius Source: Wikimedia Commons


Daniel Gabriel Fahrenheit

Like myself on being confronted with the bring back imperial weights and measures madness lots of commentators pointed out that the UK went metric in 1965 but is this true? No, it isn’t! The UK actually went metric, by act of parliament over one hundred years earlier in 1864! The nineteenth century contains some pretty stirring history concerning the struggles between the metric and imperial systems and we will now take a brief look at them.

As soon as it became in someway necessary for humans to measure things in their environment it was fairly obvious that they would use parts of their body to do so. If we want a quick approximate measure of something we still pace it out or measure it with the length of an arm or the span of our fingers. So it was natural that parts of the body became the units of measurement, the foot, the forearm, the arm span and so on and so forth. This system of course suffers from the fact that we are not all the same size. My foot is shorter than yours; my forearm is longer than my partners. This led cultures with a strong central bureaucracy to develop standard feet and forearms. The various Fertile Crescent cultures developed sophisticated weights and measures systems, as did the Roman Empire and it is the latter that is the forefather of the imperial system. The Roman foot was between 29.5 and 30 cm, the pace was 2.5 feet and the Roman mile was 5000 feet. The word mile comes from the Latin for thousand, mille. The Roman military, which was very standardised, carried the Roman system of weights and measures to large parts of Europe thus establishing their standards overall.

With the collapse of the Roman Empire their standardised system of weights and measures slowly degenerated and whilst the names were retained their dimensions varied from district to district and from town to town. In the eighth and ninth centuries Karl der Große (that’s Charlemagne for the Brits) succeeded in uniting a substantial part of Europe under his rule. Although he was uneducated and illiterate he was a strong supporter of education and what passed at the time for science and amongst his reforms he introduced a unified system of weights and measures for his entire empire, another forefather of the imperial system. Things are looking quite grim for the anti-European supporters of the imperial system; it was born in Rome the birthplace of the EU and was reborn at the hands of a German, nothing very British here.

Karl’s attempt to impose a unified system of weights and measures on his empire was not a great success and soon after his death each district and town went back to their own local standards, if they ever left them. Throughout the Middle Ages and deep into the Early Modern Period traders had to live with the fact that a foot in Liège was not the same as a foot in Venice and a pound in Copenhagen was not a pound in Vienna.

This chaos provided work for the reckoning masters producing tables of conversions or actually doing the conversions for the traders, as well as running reckoning schools for the apprentice traders where they taught the arithmetic and algebra necessary to do the conversions, writing the textbooks for the tuition as well. The lack of unity in currency and mensuration in medieval Europe was a major driving force in the development algebra – the rule of three ruled supreme.

At the beginning of the seventeenth century Simon Stevin and Christoph Clavius introduced decimal fractions and the decimal point into European mathematics, necessary requirements for a decimal based metric system of mensuration. Already in the middle of the seventeenth century just such a system emerged and not from the dastardly French but from a true blue English man, who was an Anglican bishop to boot, polymath, science supporter, communicator, founding member of the Royal Society and one of its first secretaries, John Wilkins (1614–1672).

Greenhill, John, c.1649-1676; John Wilkins (1614-1672), Warden (1648-1659)

Greenhill, John; John Wilkins (1614-1672), Warden (1648-1659); Wadham College, University of Oxford;

Asked by the society to devise a universal standard of measure he devoted four pages of his monumental An Essay towards a Real Character and a Philosophical Language (1668) to the subject.


Title Page Source: Wikimedia Commons

He proposed a decimal system of measure based on a universal measure derived from nature for use between ‘learned men’ of various nations. He considered atmospheric pressure, the earth’s meridian and the pendulum as his universal measure, rejecting the first as susceptible to variation, the second as immeasurable and settled on the length of the second pendulum as his measure of length. Volume should be the cubic of length and weight a cubic standard of water. To all extents and purposes he proposed the metric system. His proposal fell, however, on deaf ears.


European units of length in the first third of the 19th century Part 1


European units of length in the first third of the 19th century Part 2

As science developed throughout the seventeenth and eighteenth century it became obvious that some sort of universal system of measurement was a necessity and various people in various countries addressed to subject. In 1790 the revolutionary Assemblée in France commissioned the Académie to investigate the topic. A committee consisting of Jean-Charles de Borda, Joseph-Louis Lagrange, Pierre-Simon Laplace, Gaspard Monge and Nicolas de Condorcet, all leading scientific figures, recommended the adoption of a decimal metric system based on one ten-millionth of one quarter of the Earth’s circumference. The proposal was accepted by the Assemblée on 30 March 1791. Actually determining the length of one quarter of the Earth circumference turned into a major project fraught with difficulties, which I can’t do justice to here in an already overlong blog post, but if you are interested then read Ken Adler’s excellent The Measure of All Things: The Seven-Year Odyssey That Transformed The World.


Standard meter on the left of the entrance of the french Ministère de la Justice, Paris, France. Source: Wikimedia Commons

However Britain needed a unified system of mensuration, as they still had the problem that every town had different local standards for foot, pound etc. John Herschel the rising leading scientific figure wanted a new decimal imperial system based on the second pendulum but in the end parliament decide to stick with the old imperial system taking a physical yard housed in the Houses of Parliament as the standard for the whole of the UK. Unfortunately disaster struck. The Houses of Parliament burnt down in 1834 and with it the official standard yard. It took the scientists several years to re-establish the length of the official yard and meanwhile a large number were still advocating for the adoption of the metric system.


The informal public imperial measurement standards erected at the Royal Observatory, Greenwich, London, in the 19th century: 1 British yard, 2 feet, 1 foot, 6 inches, and 3 inches. The inexact monument was designed to permit rods of the correct measure to fit snugly into its pins at an ambient temperature of 62 °F (16.66 °C) Source: Wikimedia Commons

The debate now took a scurrile turn with the introduction of pyramidology! An English writer, John Taylor, developed the thesis that the Great Pyramid was constructed using the imperial system and that the imperial system was somehow divine. Strangely his ideas were adopted and championed by Charles Piazzi Smyth the Astronomer Royal of Scotland and even received tacit and indirect support from John Herschel, who rejected the pyramidology aspect but saw Taylor’s pyramid inch as the natural standard of length.

However wiser heads prevailed and the leaders of the British Victorian scientific community made major contributions to the expansion of the metric system towards the SI system, used internationally by scientists today. They applied political pressure and in 1864 the politicians capitulated and parliament passed the Metric (Weights and Measures) Act. This permitted the use of weights and measures in Britain. Further acts followed in 1867, 1868, 1871 and 1873 extending the permitted use of the metre. However the metric system could be used for scientific purposes but not for business. For that, Britain would have to wait another one hundred and one years!

Interestingly, parallel to the discussion about systems of mensuration in the nineteenth century, a discussing took place about the adoption of a single prime meridian for cartographical, navigational, and time purposes. In the end the two main contenders were the observatories in Paris and Greenwich. Naturally neither Britain nor France was prepared to concede to the other. To try and solve the stalemate it was suggested that in exchange for Paris accepting Greenwich as the prime meridian London should adopt the metric system of measurement. By the end of the nineteenth century both countries had nominally agreed to the deal without a formal commitment. Although France fulfilled their half of this deal sometime early in the twentieth century, Britain took until 1965 before they fulfilled their half.

Should the Leavers get their wish and the UK returns to the imperial system of measurement then they will be joining an elite group consisting of the USA, Myanmar and Liberia, the only countries in the world that don’t have the metric system as their national system of measurement for all purposes.


Filed under History of Mathematics, History of Navigation, History of science, Uncategorized

A birthday amongst the stars

Readers will probably be aware that as well as writing this blog I also hold, on a more or less regular basis, semi-popular, public lectures on the history of science. These lectures are as diverse as this blog and have been held in a wide variety of places. However I have, over the years, held more lectures in the Nürnberg Planetarium than anywhere else and last Thursday I was once again under the dome, this time not to hold a lecture but to help celebrate the ninetieth birthday of this august institution.

Before the twentieth century the term planetarium was a synonym for orrery, a mechanical model, which demonstrates the movements of the planets in the solar system. The beginnings of the planetarium in the modern sense was as Walther Bauersfeld, an engineer of the German optics company Zeiss, produced the plans for the construction of a planetarium projector based on earlier concepts. In 1923 the world’s first planetarium projector, the Zeiss Mark I, was demonstrated in the Zeiss factory in Jena and two months later on 21 October in the Deutschen Museum in Munich. Following further developments the first planetarium was opened in the Deutschen Museum on 7 May 1925.

Zeiss Mark I Planetarium Projector

Various German town and cities followed suit and the city council of Nürnberg signed a contract with Zeiss for a planetarium projector on 12 February 1925. The contract called for the city council to pay Zeiss 150, 000 Reichsmark ( a small fortune) in three instalments and 10% of the takings from the public shows. In a building on Rathenauplatz designed by Otto Ernst Schweizer the Nürnberg planetarium opened ninety years ago on 10 April 1927.

Original Nürnberg Planetarium

Fitted out with a new Zeiss Mark II projector the first of the so-called dumbbell design projectors with a sphere at each end for the north and south hemispheres. It was the world’s ninth planetarium.

Zeiss Mark II Planetarium Projector

From the very beginning the planetarium was born under a bad sign as the NSDAP (Nazi) city councillor, Julius Streicher, (notorious as the editor of the anti-Semitic weekly newspaper Der Stürmer) vehemently opposed the plans of the SPD council to build the planetarium. On 30 January 1933 the NSDAP seized power in Germany and the days of the planetarium were numbered. In November the planetarium director was ‘persuaded’ to recommend closing the planetarium and at the beginning of December it was closed. There were discussions about using the building for another purpose but Streicher, now Gauleiter (district commissioner) of Franconia was out for revenge. In March 1934 the planetarium was demolished on Streicher’s orders, with the argument that it looked too much like a synagogue! However the projector, and all the technical equipment, was rescued and put into storage.

Historischer Kunstbunker Entrance: There are guided tours

During the Second World War the projector was stored together with the art treasures of the city in the Historischer Kunstbunker (historical art bunker), a tunnel under the Castle of Nürnberg.

Following the war, in the 1950s, as Nürnberg was being rebuilt the city council decided to rebuild the planetarium and on 11 December 1961 it was reopened on the new site on the Plärrer, with an updated Zeiss Mark III. During the celebrations for the five hundredth anniversary of the death of Nicolaus Copernicus in 1973, whose De revolutionibus was printed and published in Nürnberg, the planetarium became the Nicolaus-Copernicus-Planetarium. In 1977 the Mark III projector was replaced with a Mark V, which is still in service and in 2010 the planetarium entered the twenty-first century with a digital Full-Dome projector.

Nicolaus-Copernicus-Planetarium am Plärrer in Nürnberg (2013)

The Zeiss Mark V Planetarium Projector in Nürnberg

Since the 1990’s the planetarium has been part of the City of Nürnberg’s adult education complex and alongside the planetarium programme it is used extensively for STEM lectures. I shall be holding my next lecture there on 28 November this year about Vannevar Bush, Claude Shannon, Robert H Goddard and William Shockley- Four Americans Who Shaped the Future (in German!) and if you’re in the area you’re welcome to come and throw peanuts.





Filed under Autobiographical, History of Astronomy, History of Optics, History of science, Uncategorized

Has The Renaissance Mathematicus gone over to the dark side?

As the ultimate anti-establishment, indie rock band, The Grateful Dead, was inducted into the Rock and Roll Hall of fame, lead guitarist, Jerry Garcia, commented something along the lines of, it’s like the neighbourhood whore, if she stands on the corner long enough then eventually she becomes part of the establishment. And so it has came to pass than your friendly neighbourhood indie, anti-establishment, arse kicking, history of science blogger, The Renaissance Mathematicus, got asked, no, not asked, invited to submit an article to the latest edition[1] of the British Society for the History of Science online journal Viewpoints! He, being the publicity whore that he is, putting aside all thoughts of tarnishing his brand or weakening his reputation accepted with alacrity. And so it is that you, dear readers, can peruse his words of wisdom in the latest edition of that honourable establishment publication. For those that brave of vicissitudes of this dubious blog at regular intervals there is nothing in the latest outpourings of the #histsci hooligan that will be new to you but there are, with certainty, many other good and worthy things to read in this excellent journal, so why don’t you just stroll on over and indulge in some first class history of science story telling.

[1] When I originally wrote this post it was the latest edition of Viewpoint but I couldn’t find a link so I never posted this. Now that I have found a link it’s still the latest issue but no longer dew fresh.


Filed under Autobiographical, History of science, Myths of Science

Sorry Caroline but you were not the first, Maria was

Today is the birthday of Caroline Herschel, important member of the Herschel astronomical clan and significant astronomer in her own right, who was born 16 March 1750.

Caroline Herschel
Source: Wikimedia Commons

Throughout the Internet this anniversary is being acknowledged and celebrated, and quite rightly so, but all of those doing so that I have stumbled across, including such august organisations as the BBC, the Royal Society, NASA and ESA amongst other, have all being perpetuating a history of astronomy myth, namely that Caroline Herschel was the first woman to discover a comet. She wasn’t Maria Kirch was!

Caroline Herschel made her first cometary discovery, having been trained to sweep for comets by her brother William and being provided by him with her own comet sweeping telescope, on 1 August 1786, almost sixty-six years after the death of her fellow German female astronomer and the real first woman to discover a comet, Maria Kirch.

Maria Kirch, who I’ve written about briefly in the past, was the wife and working partner of Gottfried Kirch, who was a pupil of Erhard Weigel and who became the first Prussian state astronomer in Berlin in 1700. Maria and Gottfried had married in 1692. On 21 April 1702 Maria discovered the so-called comet of 1702 (C/1702 H1). You will note this is eighty-four years before Caroline Herschel discovered her first comet. Unfortunately for Maria, the sexist eighteenth century attributed the discovery to her husband Gottfried and not to her. Although Gottfried publically attributed the discovery to Maria in 1710 the official attribution has not been changed to this day.

Not only was Maria Kirch robbed of recognition of her discovery in the sexist eighteenth century but people too lazy to check their facts deny her achievement every time they falsely claim that Caroline Herschel was the first woman to discovery a comet.




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