Category Archives: History of Technology

The Electric Showman

The are some figures in #histSTM, who, through some sort of metamorphosis, acquire the status of cult gurus, who were somehow super human and if only they had been properly acknowledged in their own times would have advanced the entire human race by year, decades or even centuries. The most obvious example is Leonardo da Vinci, who apparently invented, discovered, created everything that was worth inventing, discovering, creating, as well as being the greatest artist of all time. Going back a few centuries we have Roger Bacon, who invented everything that Leonardo did but wasn’t in the same class as a painter. Readers of this blog will know that one of my particular bugbears is Ada Lovelace, whose acolytes claim singlehandedly created the computer age. Another nineteenth century figure, who has been granted god like status is the Serbian physicist and inventor, Nikola Tesla (1856–1943).

The apostles of Tesla like to present him in contrast to, indeed in battle with, Thomas Alva Edison (1847–1931). According to their liturgy Tesla was a brilliant, original genius, who invented everything electrical and in so doing created the future, whereas Edison was poseur, who had no original ideas, stole everything he is credited with having invented and exploited the genius of other to create his reputation and his fortune. You don’t have to be very perceptive to realise that these are weak caricatures that almost certainly bear little relation to the truth. That this is indeed the case is shown by a new, levelheaded biography of Tesla by Iwan Rhys Morus, Tesla and the Electric Future.[1]


If anyone is up to the job of presenting a historically accurate, balanced biography of Tesla, then it is Morus, who is professor of history at Aberystwyth University and who has established himself as an expert for the history of electricity in the nineteenth century with a series of excellent monographs on the topic, and yes he delivers.

Anybody who picks up Morus’ compact biography looking for a blow by blow description of the epic war between Tesla and Edison is going to be very disappointed, because as Morus points out it basically never really took place; it is a myth. What we get instead is a superb piece of contextual history. Morus presents a widespread but deep survey of the status of electricity in the second half of the nineteenth century and the beginnings of the twentieth century into which he embeds the life story of Tesla.

We have the technological and scientific histories of electricity but also the socio-political history of the role that electricity during the century and above all the futurology. Electricity was seen as the key to the future in all areas of life in the approaching twentieth century. Electricity was hyped as the energy source of the future, as the key to local and long distant communication, and as a medical solution to both physical and psychological illness. In fact it appears that electricity was being touted as some sort of universal panacea for all of societies problems and ills. It was truly the hype of the century. Electricity featured big in the widely popular world exhibitions beginning with the Great Exhibition at Crystal Palace in 1851.


In these world fairs electricity literally outshone all of the other marvels and wonders on display.

The men, who led the promotion of this new technology, became stars, prophets of an electrical future, most notably Thomas Alva Edison, who became known as the Wizard of Menlo Park.


Far from the popular image of Edison being Tesla’s sworn enemy, he was the man, who brought Tesla to America and in doing so effectively launched Tesla’s career. Edison also served as a role model for Tesla; from Edison, Tesla learnt how to promote and sell himself as a master of the electric future.

Morus takes us skilfully through the battle of the systems, AC vs. DC in which Tesla, as opposed to popular myth, played very little active part having left Westinghouse well before the active phase. His technology, patented and licenced to Westinghouse, did, however, play a leading role in Westinghouse’s eventually victory in this skirmish over Edison, establishing Tesla as one of the giants in the electricity chess game. Tesla proceeded to establish his reputation as a man of the future through a series of public lectures and interviews, with the media boosting his efforts.

From here on in Tesla expounded ever more extraordinary, visionary schemes for the electric future but systematically failed to deliver.


His decline was long drawn out and gradual rather than spectacular and the myths began to replace the reality. The electric future forecast throughout the second half of the nineteenth century was slowly realised in the first half of the twentieth but Tesla played almost no role in its realisation.

Morus is himself a master of nineteenth century electricity and its history, as well as a first class storyteller, and in this volume he presents a clear and concise history of the socio-political, public and commercial story of electricity as it came to dominate the world, woven around a sympathetic but realistic biography of Nikola Tesla. His book is excellently researched and beautifully written, making it a real pleasure to read.  It has an extensive bibliography of both primary and secondary sources. The endnotes are almost exclusively references to the bibliography and the whole is rounded off with an excellent index. The book is well illustrated with a good selection of, in the meantime ubiquitous for #histSTM books, grey in grey prints.

Morus’ book has a prominent subtext concerning how we view our scientific and technological future and it fact this is probably the main message, as he makes clear in his final paragraph:

It is a measure of just what a good storyteller about future worlds Tesla was that we still find the story so compelling. It is also the way we still tend to tell stories about imagined futures now. We still tend to frame the way we think about scientific and technological innovation – the things on which our futures will depend – in terms of the interventions of heroic individuals battling against the odds. A hundred years after Tesla, it might be time to start thinking about other ways of talking about the shape of things to come and who is responsible who is responsible for shaping them.

If you want to learn about the history of electricity in the nineteenth century, the life of Nikola Tesla or how society projects its technological futures then I really can’t recommend Iwan Rhys Morus excellent little volume enough. Whether hardback or paperback it’s really good value for money and affordable for even the smallest of book budgets.

[1] Iwan Rhys Morus, Tesla and the Electric Future, Icon books, London, 2019



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

How Renaissance Nürnberg became the Scientific Instrument Capital of Europe

This is a writen version of the lecture that I was due to hold at the Science and the City conference in London on 7 April 2020. The conference has for obvious reasons been cancelled and will now take place on the Internet. You can view the revised conference program here.

The title of my piece is, of course, somewhat hyperbolic, as far as I know nobody has ever done a statistical analysis of the manufacture of and trade in scientific instruments in the sixteenth century. However, it is certain that in the period 1450-1550 Nürnberg was one of the leading European centres both for the manufacture of and the trade in scientific instruments. Instruments made in Nürnberg in this period can be found in every major collection of historical instruments, ranging from luxury items, usually made for rich patrons, like the column sundial by Christian Heyden (1526–1576) from Hessen-Kassel


Column Sundial by Christian Heyden Source: Museumslandschaft Hessen-Kassel

to cheap everyday instruments like this rare (rare because they seldom survive) paper astrolabe by Georg Hartman (1489–1564) from the MHS in Oxford.


Paper and Wood Astrolabe Hartmann Source: MHS Oxford

I shall be looking at the reasons why and how Nürnberg became such a major centre for scientific instruments around 1500, which surprisingly have very little to do with science and a lot to do with geography, politics and economics.

Like many medieval settlements Nürnberg began simply as a fortification of a prominent rock outcrop overlooking an important crossroads. The first historical mention of that fortification is 1050 CE and there is circumstantial evidence that it was not more than twenty or thirty years old. It seems to have been built in order to set something against the growing power of the Prince Bishopric of Bamberg to the north. As is normal a settlement developed on the downhill slopes from the fortification of people supplying services to it.


A fairly accurate depiction of Nürnberg from the Nuremberg Chronicle from 1493. The castles (by then 3) at the top with the city spreading down the hill. Large parts of the inner city still look like this today

Initially the inhabitants were under the authority of the owner of the fortification a Burggraf or castellan. With time as the settlement grew the inhabitants began to struggle for independence to govern themselves.

In 1200 the inhabitants received a town charter and in 1219 Friedrich II granted the town of Nürnberg a charter as a Free Imperial City. This meant that Nürnberg was an independent city-state, which only owed allegiance to the king or emperor. The charter also stated that because Nürnberg did not possess a navigable river or any natural resources it was granted special tax privileges and customs unions with a number of southern German town and cities. Nürnberg became a trading city. This is where the geography comes into play, remember that important crossroads. If we look at the map below, Nürnberg is the comparatively small red patch in the middle of the Holy Roman Empire at the beginning of the sixteenth century. If your draw a line from Paris to Prague, both big important medieval cities, and a second line from the border with Denmark in Northern Germany down to Venice, Nürnberg sits where the lines cross almost literally in the centre of Europe. Nürnberg also sits in the middle of what was known in the Middle Ages as the Golden Road, the road that connected Prague and Frankfurt, two important imperial cities.


You can also very clearly see Nürnberg’s central position in Europe on Erhard Etzlaub’s  (c. 1460–c. 1531) pilgrimage map of Europe created for the Holy Year of 1500. Nürnberg, Etzlaub’s hometown, is the yellow patch in the middle. Careful, south is at the top.


Over the following decades and centuries the merchant traders of Nürnberg systematically expanded their activities forming more and more customs unions, with the support of various German Emperors, with towns, cities and regions throughout the whole of Europe north of Italy. Nürnberg which traded extensively with the North Italian cities, bringing spices, silk and other eastern wares, up from the Italian trading cities to distribute throughout Europe, had an agreement not to trade with the Mediterranean states in exchange for the Italians not trading north of their northern border.

As Nürnberg grew and became more prosperous, so its political status and position within the German Empire changed and developed. In the beginning, in 1219, the Emperor appointed a civil servant (Schultheis), who was the legal authority in the city and its judge, especially in capital cases. The earliest mention of a town council is 1256 but it can be assumed it started forming earlier. In 1356 the Emperor, Karl IV, issued the Golden Bull at the Imperial Diet in Nürnberg. This was effectively a constitution for the Holy Roman Empire that regulated how the Emperor was to be elected and, who was to be appointed as the Seven Prince-electors, three archbishops and four secular rulers. It also stipulated that the first Imperial Diet of a newly elected Emperor was to be held in Nürnberg. This stipulation reflects Nürnberg’s status in the middle of the fourteenth century.

The event is celebrated by the mechanical clock ordered by the town council to be constructed for the Frauenkirche, on the market place in 1506 on the 150th anniversary of the Golden Bull, which at twelve noon displays the seven Prince-electors circling the Emperor.


Mechanical clock on the Frauenkirche overlooking the market place in Nürnberg. Ordered by the city council in 1506 to celebrate the 150th anniversary of the issuing of the Golden Bull at the Imperial Diet in 1356

Over time the city council had taken more and more power from the Schultheis and in 1385 they formally bought the office, integrating it into the councils authority, for 8,000 gulden, a small fortune. In 1424 Emperor, Sigismund appointed Nürnberg the permanent residence of the Reichskleinodien (the Imperial Regalia–crown, orb, sceptre, etc.).


The Imperial Regalia

This raised Nürnberg in the Imperial hierarchy on a level with Frankfurt, where the Emperor was elected, and Aachen, where he was crowned. In 1427, the Hohenzollern family, current holders of the Burggraf title, sold the castle, which was actually a ruin at that time having been burnt to the ground by the Bavarian army, to the town council for 120,000 gulden, a very large fortune. From this point onwards Nürnberg, in the style of Venice, called itself a republic up to 1806 when it was integrated into Bavaria.

In 1500 Nürnberg was the second biggest city in Germany, after Köln, with a population of approximately 40,000, about half of which lived inside the impressive city walls and the other half in the territory surrounding the city, which belonged to it.


Map of the city-state of Nürnberg by Abraham Ortelius 1590. the city itself is to the left just under the middle of the map. Large parts of the forest still exists and I live on the northern edge of it, Dormitz is a neighbouring village to the one where I live.

Small in comparison to the major Italian cities of the period but even today Germany is much more decentralised with its population more evenly distributed than other European countries. It was also one of the richest cities in the whole of Europe.


Nürnberg, Plan by Paul Pfinzing, 1594 Castles in the top left hand corner

Nürnberg’s wealth was based on two factors, trading, in 1500 at least 27 major trade routes ran through Nürnberg, which had over 90 customs unions with cities and regions throughout Europe, and secondly the manufacture of trading goods. It is now time to turn to this second branch of Nürnberg’s wealth but before doing so it is important to note that whereas in other trading centres in Europe individual traders competed with each other, Nürnberg function like a single giant corporation, with the city council as the board of directors, the merchant traders cooperating with each other on all levels for the general good of the city.

In 1363 Nürnberg had more than 1200 trades and crafts masters working in the city. About 14% worked in the food industry, bakers, butchers, etc. About 16% in the textile industry and another 27% working leather. Those working in wood or the building branch make up another 14% but the largest segment with 353 masters consisted of those working in metal, including 16 gold and silver smiths. By 1500 it is estimated that Nürnberg had between 2,000 and 3,000 trades and crafts master that is between 10 and 15 per cent of those living in the city with the metal workers still the biggest segment. The metal workers of Nürnberg produced literally anything that could be made of metal from sewing needles and nails to suits of armour. Nürnberg’s reputation as a producer rested on the quality of its metal wares, which they sold all over Europe and beyond. According to the Venetian accounts books, Nürnberg metal wares were the leading export goods to the orient. To give an idea of the scale of production at the beginning of the 16th century the knife makers and the sword blade makers (two separate crafts) had a potential production capacity of 80,000 blades a week. The Nürnberger armourers filled an order for armour for 5,000 soldiers for the Holy Roman Emperor, Karl V (1500–1558).

The Nürnberger craftsmen did not only produce goods made of metal but the merchant traders, full blood capitalists, bought into and bought up the metal ore mining industry–iron, copper, zinc, gold and silver–of Middle Europe, and beyond, (in the 16th century they even owned copper mines in Cuba) both to trade in ore and to smelt ore and trade in metal as well as to ensure adequate supplies for the home production. The council invested heavily in the industry, for example, providing funds for the research and development of the world’s first mechanical wire-pulling mill, which entered production in 1368.


The wirepulling mills of Nürnberg by Albrecht Dürer

Wire was required in large quantities to make chainmail amongst other things. Around 1500 Nürnberg had monopolies in the production of copper ore, and in the trade with steel and iron.  Scientific instruments are also largely made of metal so the Nürnberger gold, silver and copper smiths, and toolmakers also began to manufacture them for the export trade. There was large scale production of compasses, sundials (in particular portable sundials), astronomical quadrants, horary quadrants, torquetum, and astrolabes as well as metal drawing and measuring instruments such as dividers, compasses etc.

The city corporation of Nürnberg had a couple of peculiarities in terms of its governance and the city council that exercised that governance. Firstly the city council was made up exclusively of members of the so-called Patrizier. These were 43 families, who were regarded as founding families of the city all of them were merchant traders. There was a larger body that elected the council but they only gave the nod to a list of the members of the council that was presented to them. Secondly Nürnberg had no trades and crafts guilds, the trades and crafts were controlled by the city council. There was a tight control on what could be produced and an equally tight quality control on everything produced to ensure the high quality of goods that were traded. What would have motivated the council to enter the scientific instrument market, was there a demand here to be filled?

It is difficult to establish why the Nürnberg city corporation entered the scientific instrument market before 1400 but by the middle of the 15th century they were established in that market. In 1444 the Catholic philosopher, theologian and astronomer Nicolaus Cusanus (1401–1464) bought a copper celestial globe, a torquetum and an astrolabe at the Imperial Diet in Nürnberg. These instruments are still preserved in the Cusanus museum in his birthplace, Kues on the Mosel.


The Cusanus Museum in Kue

In fact the demand for scientific instrument rose sharply in the 15th & 16th centuries for the following reasons. In 1406 Jacopo d’Angelo produced the first Latin translation of Ptolemy’s Geographia in Florence, reintroducing mathematical cartography into Renaissance Europe. One can trace the spread of the ‘new’ cartography from Florence up through Austria and into Southern Germany during the 15th century. In the early 16th century Nürnberg was a major centre for cartography and the production of both terrestrial and celestial globes. One historian of cartography refers to a Viennese-Nürnberger school of mathematical cartography in this period. The availability of the Geographia was also one trigger of a 15th century renaissance in astronomy one sign of which was the so-called 1st Viennese School of Mathematics, Georg von Peuerbach (1423–1461) and Regiomontanus (1436–176), in the middle of the century. Regiomontanus moved to Nürnberg in 1471, following a decade wandering around Europe, to carry out his reform of astronomy, according to his own account, because Nürnberg made the best astronomical instruments and had the best communications network. The latter a product of the city’s trading activities. When in Nürnberg, Regiomontanus set up the world’s first scientific publishing house, the production of which was curtailed by his early death.

Another source for the rise in demand for instruments was the rise in interest in astrology. Dedicated chairs for mathematics, which were actually chairs for astrology, were established in the humanist universities of Northern Italy and Krakow in Poland early in the 15th century and then around 1470 in Ingolstadt. There were close connections between Nürnberg and the Universities of Ingolstadt and Vienna. A number of important early 16th century astrologers lived and worked in Nürnberg.

The second half of the 15th century saw the start of the so-called age of exploration with ships venturing out of the Iberian peninsular into the Atlantic and down the coast of Africa, a process that peaked with Columbus’ first voyage to America in 1492 and Vasco da Gama’s first voyage to India (1497–199). Martin Behaim(1459–1507), son of a Nürnberger cloth trading family and creator of the oldest surviving terrestrial globe, sat on the Portuguese board of navigation, probably, according to David Waters, to attract traders from Nürnberg to invest in the Portuguese voyages of exploration.  This massively increased the demand for navigational instruments.


The Erdapfel–the Behaim terrestial globe Germanische National Museum

Changes in the conduct of wars and in the ownership of land led to a demand for better, more accurate maps and the more accurate determination of boundaries. Both requiring surveying and the instruments needed for surveying. In 1524 Peter Apian (1495–1552) a product of the 2nd Viennese school of mathematics published his Cosmographia in Ingolstadt, a textbook for astronomy, astrology, cartography and surveying.


The Cosmographia went through more than 30 expanded, updated editions, but all of which, apart from the first, were edited and published by Gemma Frisius (1508–1555) in Louvain. In 1533 in the third edition Gemma Frisius added an appendix Libellus de locorum describendum ratione, the first complete description of triangulation, the central method of cartography and surveying down to the present, which, of course in dependent on scientific instruments.


In 1533 Apian’s Instrumentum Primi Mobilis 


was published in Nürnberg by Johannes Petreius (c. 1497–1550) the leading scientific publisher in Europe, who would go on ten years later to publish, Copernicus’ De revolutionibus, which was a high point in the astronomical revival.

All of this constitutes a clear indication of the steep rise in the demand for scientific instruments in the hundred years between 1450 and 1550; a demand that the metal workers of Nürnberg were more than happy to fill. In the period between Regiomontanus and the middle of the 16th century Nürnberg also became a home for some of the leading mathematici of the period, mathematicians, astronomers, astrologers, cartographers, instrument makers and globe makers almost certainly, like Regiomontanus, at least partially attracted to the city by the quality and availability of the scientific instruments.  Some of them are well known to historians of Renaissance science, Erhard Etzlaub, Johannes Werner, Johannes Stabius (not a resident but a frequent visitor), Georg Hartmann, Johannes Neudörffer and Johannes Schöner.**

There is no doubt that around 1500, Nürnberg was one of the major producers and exporters of scientific instruments and I hope that I have shown above, in what is little more than a sketch of a fairly complex process, that this owed very little to science but much to the general geo-political and economic developments of the first 500 years of the city’s existence.

WI12; WI33 WI3; WI2; WI30;

One of the most beautiful sets on instruments manufactured in Nürnberg late 16th century. Designed by Johannes Pretorius (1537–1616), professor for astronomy at the Nürnberger University of Altdorf and manufactured by the goldsmith Hans Epischofer (c. 1530–1585) Germanische National Museum


**for an extensive list of those working in astronomy, mathematics, instrument making in Nürnberg (542 entries) see the history section of the Astronomie in Nürnberg website, created by Dr Hans Gaab.












Filed under Early Scientific Publishing, History of Astronomy, History of Cartography, History of Mathematics, History of Navigation, History of science, History of Technology, Renaissance Science

The Renaissance Mathematicus Christmas Trilogies explained for newcomers


Being new to the Renaissance Mathematicus one might be excused if one assumed that the blogging activities were wound down over the Christmas period. However, exactly the opposite is true with the Renaissance Mathematicus going into hyper-drive posting its annual Christmas Trilogy, three blog posts in three days. Three of my favourite scientific figures have their birthday over Christmas–Isaac Newton 25thDecember, Charles Babbage 26thDecember and Johannes Kepler 27thDecember–and I write a blog post for each of them on their respective birthdays. Before somebody quibbles I am aware that the birthdays of Newton and Kepler are both old style, i.e. on the Julian Calendar, and Babbage new style, i.e. on the Gregorian Calendar but to be honest, in this case I don’t give a shit. So if you are looking for some #histSTM entertainment or possibly enlightenment over the holiday period the Renaissance Mathematicus is your number one address. In case the new trilogy is not enough for you:

The Trilogies of Christmas Past

Christmas Trilogy 2009 Post 1

Christmas Trilogy 2009 Post 2

Christmas Trilogy 2009 Post 3

Christmas Trilogy 2010 Post 1

Christmas Trilogy 2010 Post 2

Christmas Trilogy 2010 Post 3

Christmas Trilogy 2011 Post 1

Christmas Trilogy 2011 Post 2

Christmas Trilogy 2011 Post 3

Christmas Trilogy 2012 Post 1

Christmas Trilogy 2012 Post 2

Christmas Trilogy 2012 Post 3

Christmas Trilogy 2013 Post 1

Christmas Trilogy 2013 Post 2

Christmas Trilogy 2013 Post 3

Christmas Trilogy 2014 Post 1

Christmas Trilogy 2014 Post 2

Christmas Trilogy 2014 Post 3

Christmas Trilogy 2015 Post 1

Christmas Trilogy 2015 Post 2

Christmas Trilogy 2015 Post 3

Christmas Trilogy 2016 Post 1

Christmas Trilogy 2016 Post 2

Christmas Trilogy 2016 Post 3

Christmas Trilogy 2017 Post 1

Christmas Trilogy 2017 Post 2

Christmas Trilogy 2017 Post 3

Christmas Trilogy 2018 Post 1

Christmas Trilogy 2018 Post 2

Christmas Trilogy 2018 Post 3






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Filed under History of Astronomy, History of Mathematics, History of Physics, History of science, History of Technology, Uncategorized

Mathematical aids for Early Modern astronomers.

Since its very beginnings in the Fertile Crescent, European astronomy has always involved a lot of complicated and tedious mathematical calculations. Those early astronomers described the orbits of planets, lunar eclipses and other astronomical phenomena using arithmetical or algebraic algorithms. In order to simplify the complex calculations needed for their algorithms the astronomers used pre-calculated tables of reciprocals, squares, cubes, square roots and cube roots.


Cuniform reciprocal table Source

The ancient Greeks, who inherited their astronomy from the Babylonians, based their astronomical models on geometry rather than algebra and so needed other calculation aids. They developed trigonometry for this work based on chords of a circle. The first chord tables are attributed to Hipparkhos (c. 190–c. 120 BCE) but they did not survive. The oldest surviving chord tables are in Ptolemaeus’ Mathēmatikē Syntaxis written in about 150 CE, which also contains a detailed explanation of how to calculate such a table in Chapter 10 of Book I.


Ptolemaeus’ Chord Table taken from Toomer’s Almagest translation. The 3rd and 6th columns are the interpolations necessary for angles between the given ones

Greek astronomy travelled to India, where the astronomers replaced Ptolemaeus’ chords with half chords, that is our sines. Islamic astronomers inherited their astronomy from the Indians with their sines and cosines and the Persian astronomer Abū al-Wafāʾ (940–998 CE) was using all six of the trigonometrical relations that we learnt at school (didn’t we!) in the tenth century.


Abū al-Wafāʾ Source: Wikimedia Commons

Astronomical trigonometry trickled slowly into medieval Europe and Regiomontanus (1536–1576)  (1436–1476) was the first European to produce a comprehensive work on trigonometry for astronomers, his De triangulis omnimodis, which was only edited by Johannes Schöner and published by Johannes Petreius in 1533.

Whilst trigonometry was a great aid to astronomers calculating trigonometrical tables was time consuming, tedious and difficult work.

A new calculating aid for astronomers emerged during the sixteenth century, prosthaphaeresis, by which, multiplications could be converted into additions using a series of trigonometrical identities:

Prosthaphaeresis appears to have first been used by Johannes Werner (1468–1522), who used the first two formulas with both sides multiplied by two.

However Werner never published his discovery and it first became known through the work of the itinerant mathematician Paul Wittich (c. 1546–1586), who taught it to both Tycho Brahe (1546–1601) on his island of Hven and to Jost Bürgi (1552–1632) in Kassel, who both developed it further. It is not known if Wittich learnt the method from Werner’s papers on one of his visits to Nürnberg or rediscovered it for himself. Bürgi in turn taught it to Nicolaus Reimers Baer (1551–1600) in in exchange translated Copernicus’ De revolutionibus into German for Bürgi, who couldn’t read Latin. This was the first German translation of De revolutionibus. As can be seen the method of prosthaphaeresis spread throughout Europe in the latter half of the sixteenth century but was soon to be superceded by a superior method of simplifying astronomical calculations by turning multiplications into additions, logarithms.

As is often the case in the histories of science and mathematics logarithms were not discovered by one person but almost simultaneously, independently by two, Jost Bürgi and John Napier (1550–1617) and both of them seem to have developed the idea through their acquaintance with prosthaphaeresis. I have already blogged about Jost Bürgi, so I will devote the rest of this post to John Napier.


John Napier, artist unknown Source: Wikimedia Commons

John Napier was the 8th Laird of Merchiston, an independently owned estate in the southwest of Edinburgh.


Merchiston Castle from an 1834 woodcut Source: Wikimedia Commons

His exact date of birth is not known and also very little is known about his childhood or education. It is assumed that he was home educated and he was enrolled at the University of St. Andrews at the age of thirteen. He appears not to have graduated at St. Andrews but is believed to have continued his education in Europe but where is not known. He returned to Scotland in 1571 fluent in Greek but where he had acquired it is not known. As a laird he was very active in the local politics. His intellectual reputation was established as a theologian rather than a mathematician.

It is not known how and when he became interested in mathematics but there is evidence that this interest was already established in the early 1570s, so he may have developed it during his foreign travels. It is thought that he learnt of prosthaphaeresis through John Craig (d. 1620) a Scottish mathematician and physician, who had studied and later taught at Frankfurt an der Oder, a pupil of Paul Wittich, who knew Tycho Brahe. Craig returned to Edinburgh in 1583 and is known to have had contact with Napier. The historian Anthony à Wood (1632–1695) wrote:

one Dr. Craig … coming out of Denmark into his own country called upon John Neper, baron of Murcheston, near Edinburgh, and told him, among other discourses, of a new invention in Denmark (by Longomontanus as ’tis said) to save the tedious multiplication and division in astronomical calculations. Neper being solicitous to know farther of him concerning this matter, he could give no other account of it than that it was by proportionable numbers. [Neper is the Latin version of his family name]

Napier is thought to have begum work on the invention of logarithms about 1590. Logarithms exploit the relation ship between arithmetical and geometrical series. In modern terminology, as we all learnt at school, didn’t we:

Am x An = Am+n

Am/An = Am-n

These relationships were discussed by various mathematicians in the sixteenth century, without the modern notation, in particularly by Michael Stefil (1487–1567) in his Arithmetica integra (1544).


Michael Stifel Source: Wikimedia Commons


Michael Stifel’s Arithmetica Integra (1544) Source: Wikimedia Commons

What the rules for exponents show is that if one had tables to convert all numbers into powers of a given base then one could turn all multiplications and divisions into simple additions and subtractions of the exponents then using the tables to covert the result back into a number. This is what Napier did calling the result logarithms. The methodology Napier used to calculate his tables is too complex to deal with here but the work took him over twenty years and were published in his Mirifici logarithmorum canonis descriptio… (1614).


Napier coined the term logarithm from the Greek logos (ratio) and arithmos (number), meaning ratio-number. As well as the logarithm tables, the book contains seven pages of explanation on the nature of logarithms and their use. A secondary feature of Napier’s work is that he uses full decimal notation including the decimal point. He was not the first to do so but his doing so played an important role in the acceptance of this form of arithmetical notation. The book also contains important developments in spherical trigonometry.

Edward Wright  (baptised 1561–1615) produced an English translation of Napier’s Descriptio, which was approved by Napier, A Description of the Admirable Table of Logarithmes, which was published posthumously in 1616 by his son Samuel.


Gresham College was quick to take up Napier’s new invention and this resulted in Henry Briggs (1561–1630), the Gresham professor of geometry, travelling to Edinburgh from London to meet with Napier. As a result of this meeting Briggs, with Napier’s active support, developed tables of base ten logarithms, Logarithmorum chilias prima, which were publish in London sometime before Napier’s death in 1617.


He published a second extended set of base ten tables, Arithmetica logarithmica, in 1624.


Napier’s own tables are often said to be Natural Logarithms, that is with Euler’s number ‘e’ as base but this is not true. The base of Napierian logarithms is given by:

NapLog(x) = –107ln (x/107)

Natural logarithms have many fathers all of whom developed them before ‘e’ itself was discovered and defined; these include the Jesuit mathematicians Gregoire de Saint-Vincent (1584–1667) and Alphonse Antonio de Sarasa (1618–1667) around 1649, and Nicholas Mercator (c. 1620–1687) in his Logarithmotechnia (1688) but John Speidell (fl. 1600–1634), had already produced a table of not quite natural logarithms in 1619.


Napier’s son, Robert, published a second work by his father on logarithms, Mirifici logarithmorum canonis constructio; et eorum ad naturales ipsorum numeros habitudines, posthumously in 1619.


This was actually written earlier than the Descriptio, and describes the principle behind the logarithms and how they were calculated.

The English mathematician Edmund Gunter (1581–1626) developed a scale or rule containing trigonometrical and logarithmic scales, which could be used with a pair of compasses to solve navigational problems.


Table of Trigonometry, from the 1728 Cyclopaedia, Volume 2 featuring a Gunter’s scale Source: Wikimedia Commons

Out of two Gunter scales laid next to each other William Oughtred (1574–1660) developed the slide rule, basically a set of portable logarithm tables for carry out calculations.

Napier developed other aids to calculation, which he published in his Rabdologiae, seu numerationis per virgulas libri duo in 1617; the most interesting of which was his so called Napier’s Bones.


These are a set of multiplication tables embedded in rods. They can be used for multiplication, division and square root extraction.


An 18th century set of Napier’s bones Source: Wikimedia Commons

Wilhelm Schickard’s calculating machine incorporated a set of cylindrical Napier’s Bones to facilitate multiplication.

The Swiss mathematician Jost Bürgi (1552–1632) produced a set of logarithm tables independently of Napier at almost the same time, which were however first published at Kepler’s urging as, Arithmetische und Geometrische Progress Tabulen…, in 1620. However, unlike Napier, Bürgi delivered no explanation of the how his table were calculated.


Tables of logarithms became the standard calculation aid for all those making mathematical calculations down to the twentieth century. These were some of the mathematical tables that Babbage wanted to produce and print mechanically with his Difference Engine. When I was at secondary school in the 1960s I still carried out all my calculations with my trusty set of log tables, pocket calculators just beginning to appear as I transitioned from school to university but still too expensive for most people.


Not my copy but this is the set of log tables that accompanied me through my school years

Later in the late 1980s at university in Germany I had, in a lecture on the history of calculating, to explain to the listening students what log tables were, as they had never seen, let alone used, them. However for more than 350 years Napier’s invention served all those, who needed to make mathematical calculations well.














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

Revealing the secrets of the fire-using arts

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


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

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

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


Siena 1568

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


Petrucci coat of arms Source: Wikimedia Commons

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

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

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



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



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


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





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



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

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







Book VII the various methods of melting metals.







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


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




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



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


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



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

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

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








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

A book for lunatics

The world has currently gone moon crazy, because it is now fifty years since a couple of American went for a walk on the moon. This has meant the usual flood of books, journal, magazine and newspaper articles, blog post and, Twitter and Facebook postings that now accompany any such #histSTM anniversary that is considered by the media world to be significant enough. With the following statement I shall probably lose half of my Twitter following overnight but personally I don’t find this particular anniversary especially interesting. I do have one peculiar biographical quirk in that I don’t think I actually watched that first moon landing; at least I have absolutely no memory of having done so. The last weeks of the school year 1968–69 were a highly emotional time for me. I had just been expelled from boarding school but was still living there as my fees were paid up to the end of the school year and my parents were away on sabbatical in Indonesia. Somehow all of that was more important in my life than some guys going for a walk on the moon.

Although I have skimmed the occasional newspaper/magazine/Internet article I have not and will not bother to buy and read any of the apparently X zillion books that have been thrown onto the market to celebrate the occasion. I will admit to having treated myself to Ewen A. Whitaker’s Mapping and Naming the MoonA History of Lunar Cartography and Nomenclature (CUP, ppb. 2003), which actually has little to do with the actual anniversary. I have however acquired and read one book written specifically for the anniversary Oliver Morton’s The Moon: A History for the Future (The Economist Books, 2019). I got this for free because I read and suggested corrections for those bits of the book dealing with the Early Modern Period. Although, I saved the author from making, what I consider to be a serious error but which the normal reader probably wouldn’t even have noticed, I think my contribution to the final product was so minimal that I can safely review it without fear of personal bias.


We’ll start at the top with the very simple statement; this is truly an excellent book. I would be very tempted to say, if you only read one book on the moon this year then you could do worse than choose this one. However, not having read any of the others, this would not be very fair to the other moon book authors. Back to the praise, Morton’s book is a wonderful literary tour de force, which is also incredibly informative. He combines the histories of astronomy, technology, the moon landings and science fiction to create a stimulating potpourri of lunar lore and selenology.

The book is divided into eight sections rather than chapters, each of which deals with a different aspect of humanity’s relationship with the Moon. Section I introduces the reader to the phenomenon of earthshine, the light reflected from the Earth that illuminates those parts of the Moon not lit by the Sun, both its discovery in the Early Modern Period and its use in modern times for scientific experiments. Section II deals with studies of the Moon’s appearance from the High Middle Ages down to the twentieth century. Section III takes us along the path of the development of rocketry up to Apollo and then with Armstrong, Aldrin and Collins on Apollo 11 to that first ever moon landing. Section IV takes a look at the various theories to explain the origins of the Moon and its geology. Section V deals with the end or better said the collapse of the Apollo program and then over the years the various suggestions for economically viable schemes to return to the Moon, here Morton demonstrates his strengths as a narrator. Although he is obviously a space fan he carefully details why such schemes were largely unrealistic or impractical. Section VI examines the various schemes currently being developed for a real return. Having got there, section VII discusses what to do when we get there if we do go back. Section VIII looks at negative literary depictions of the Moon illustrating rather nicely that maybe the Moon isn’t such an attractive place to visit.

This listing of the main themes of each section doesn’t do Morton’s inventiveness justice. He weaves lots of side topics into the weft of his main narratives taking his readers down many highways and byways, leaving the readers with the impression that he has consumed a vast library of lunar information, an impression strengthened by the extensive bibliography.  His real achievement is to pack so much fascinating information into so few pages, whilst retaining a wonderful light readable style. His book is both an encyclopaedia and a work of art.




Filed under Book Reviews, History of Astronomy, History of science, History of Technology

Renaissance Heavy Metal

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


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

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


Silver mining in Joachimsthal (1548) Source: Wikimedia Commons

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

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


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


Source: Internet Archive

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

De ortu et causis subterraneorum libri V, Basel 1546

The origin of material within the earth

De natura eorum, quae effluunt ex terra, Basel 1546

The nature of the material extruded out of the earth

De veteribus et novis metallis libri II, Basel 1546

Ore mining in antiquity and in modern times

De natura fossilium libri X, Basel 1546

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

De animantibus subterraneis liber, Basel 1549

The living underground

De precio metallorum et monetis liber III, 1550

On precious metals and coins

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

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


Book I: Discusses the industry of mining and ore smelting

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

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

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

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

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

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Book VII: Discusses assaying ores and metals and the touchstone

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

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

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

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

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

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

metallica tp001


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


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


Lou Henry, circa 1930 Source: Wikimedia Commons

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

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

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






Filed under Early Scientific Publishing, History of Technology, Mediaeval Science, Renaissance Science

The Jesuit Mirror Man

Although the theory that a curved mirror can focus an image was already known to Hero of Alexandria in antiquity and also discussed by Leonardo in his unpublished writings; as far as we know, the first person to attempt to construct a reflecting telescope was the Italian Jesuit Niccolò Zucchi.


Niccolò Zucchi Source: Wikimedia Commons

Niccolò Zucchi, born in Parma 6 December 1586, was the fourth of eight children of the aristocrat Pierre Zucchi and his wife Francoise Giande Marie. He studied rhetoric in Piacenza and philosophy and theology in Parma, probably in Jesuit colleges. He entered the Jesuit order as a novice 28 October 1602, aged 16. Zucchi taught mathematics, rhetoric and theology at the Collegio Romano and was then appointed rector of the new Jesuit College in Ravenna by Cardinal Alessandro Orsini, who was also a patron of Galileo.

In 1623 he accompanied Orsini, the Papal legate, on a visit to the court of the Holy Roman Emperor Ferdinand II in Vienna. Here he met and got to know Johannes Kepler the Imperial Mathematicus. Kepler encouraged Zucchi’s interest in astronomy and the two corresponded after Zucchi’s return to Italy. Later when Kepler complained about his financial situation, Zucchi sent him a refracting telescope at the suggestion of Paul Guldin (1577–1643) a Swiss Jesuit mathematician, who also corresponded regularly with Kepler. Kepler mentions this gift in his Somnium. These correspondences between Kepler and leading Jesuit mathematicians illustrate very clearly how the scientific scholars in the early seventeenth century cooperated with each other across the religious divide, even at the height of the Counter Reformation.

Zucchi’s scientific interests extended beyond astronomy; he wrote and published two books on the philosophy of machines in 1646 and 1649. His unpublished Optica statica has not survived. He also wrote about magnetism, barometers, where he a good Thomist rejected the existence of a vacuum, and was the first to demonstrate that phosphors generate rather than store light.

Today, however Zucchi is best remember for his astronomy. He is credited with being the first, together with the Jesuit Daniello Bartoli (1608–1685), to observe the belts of Jupiter on 17 May 1630.  He reported observing spots on Mars in 1640. These observations were made with a regular Galilean refractor but it is his attempt to construct a reflecting telescope that is most fascinating.

In his Optica philosophia experimentis et ratione a fundamentis constituta published in 1652 he describes his attempt to create a reflecting telescope.


Optica philosophia title page Source: Linder Hall Library

As I said at the beginning, and have described in greater detail here, the principle that one could create an image with a curved mirror had been known since antiquity. Zucchi tells us that he replaced the convex objective lens in a Galilean telescope with bronze curved mirror. He tried viewing the image with the eyepiece, a concave lens looking down the tube into the mirror. He had to tilt the tube so as not to obstruct the light with his head. He was very disappointed with the result as the image was just a blur, although as he said the mirror was, “ab experto et accuratissimo artifice eleboratum nactus.” Or in simple words, the mirror was very well made by an expert.


Optica philosophia frontispiece

Zucchi had stumbled on a problem that was to bedevil all the early attempts to construct a reflecting telescope. Mirror that don’t distort the image are much harder to grind and polish than lenses. (The bending of light in a lens diminishes the effect of imperfections, whereas a mirror amplifies them). The first to solve this problem was Isaac Newton, proving that he was as skilled a craftsman as he was a great thinker. However, it would be more that fifty years before John Hadley could consistently repeat Newton’s initial success.

All the later reflecting telescope models had, as well as their primary mirrors, a secondary mirror at the focal point that reflected the image either to the side (a Newtonian), or back through the primary mirror (a Gregorian or a Cassegrain) to the eyepiece; the Zucchi remained the only single mirror telescope in the seventeenth century.

In the eighteenth century William Herschel initially built and used Newtonians but later he constructed two massive reflecting telescopes, first a twenty-foot and then a second forty-foot instrument.


Herschel’s Grand Forty feet Reflecting Telescopes A hand-coloured illustration of William Herschel’s massive reflecting telescope with a focal length of forty feet, which was erected at his home in Slough. Completed in 1789, the telescope became a local tourist attraction and was even featured on Ordnance Survey maps. By 1840, however, it was no longer used and was dismantled, although part of it is now on display at the Royal Observatory, Greenwich. This image of the telescope was engraved for the Encyclopedia Londinensis in 1819 as part of its treatment of optics. Herschel’s Grand Forty feet Reflecting Telescopes Source: Wikimedia Commons

These like Zucchi’s instrument only had a primary mirror with Herschel viewing the image with a hand held eyepiece from the front of the tube. As we name telescopes after their initial inventors Herschel giant telescopes are Zucchis, although I very much doubt if he even knew of the existence of his Jesuit predecessor, who had died at the grand old age of eighty-three in 1670.



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

Apples & Pears – comparing print technologies


On Facebook I recently stumbled across a link to a piece on 3 Quarks Daily, which in turn was only a lede for a short essay on the London Review of Books entitled, The Oldest Printed Book in the World. This is an article about the Chinese Dunhuang Diamond Sūtra


Frontispiece of the Chinese Diamond Sūtra, the oldest known dated printed book in the world. The colophon, at the inner end, reads: Reverently [caused to be] made for universal free distribution by Wang Jie on behalf of his two parents on the 13th of the 4th moon of the 9th year of Xiantong [i.e. 11th May, CE 868 ] Source: British Library via Wikimedia Commons

 from the ninth century explaining its origin and how it came to be housed in the British Library. The article contains the following sentence:

A colophon at the end of the Dunhuang Diamond Sūtra scroll dates it to 868, nearly six centuries before the first Gutenberg Bible.

Although not stated explicitly the intention of this sentence seems to be, the Chinese invented book printing six hundred years before the Europeans. Although on a very superficial level this is true it is actually a case of comparing apples with pears, as the two books in question are printed with very different reproduction technologies. The Dunhuang Diamond Sūtra is a woodblock print, whereas the Gutenberg Bible is printed with movable type.


First page of the first volume: The Epistle of St. Jerome from the University of Texas copy. Source: Ransom Center of the University of Texas at Austin via Wikimedia Commons

For woodblock printing the image to be printed is carved into a woodblock or rather the parts that are not to be printed are cut away with a knife or chisel. This is then inked and pressed onto the sheet of material, cloth or paper, to be printed. The used block produced by this difficult process can only be used to print this one page. With moveable type the individual pieces of type, or sorts, are composed into the image to be printed, inked and pressed into the sheet of material to be printed. When finished the sorts can be reused to compose a new page and so on. Once cut a set of woodblocks can only be used to print the same book over and over again. A full set of type can be continually reconfigured to print literally thousand of different books. This difference is important and the six hundred year gap throws up some very important and intriguing historical questions.


A case of cast metal type pieces and typeset matter in a composing stick Source: Wikimedia Commons

Central to these is the question of technological transfer. Woodblock printing was developed in East Asia sometime before the third century CE. The oldest fragments of printed cloth date to 220 CE. The oldest woodblock prints on paper date to the late seventh century CE. And as stated above to oldest extant woodblock printed book the Dunhuang Diamond Sūtra dates to 868 CE. Although the Chinese invention of paper arrived in Spain via the Islamic Empire in the late eleventh century CE and crossed the Alps into Northern Europe in the late fourteenth century CE, woodblock printing does not appear to have accompanied it. Strangely European books printed with woodblocks, block books, apparently only appeared after Gutenberg had introduced printing with movable type in the second half of the fifteenth century. There are a very limited number of such books mostly dating from the 1460s and 1470s and printed in the Netherlands of Southern Germany.


Block book – Biblia Pauperum (“Bible of the Poor”) Netherlands 1460s/70s Source: Wikimedia Commons

Gutenberg was by no means the first to use moveable type. Around 1040 CE a Chinese inventor, Bi Sheng (990–1051) invented a form of moveable type with the pieces of type made of ceramics. Beyond a short description of his invention nothing more is known about it and nothing he might have printed has survived. This was followed in East Asia by various other forms of moveable type carved from wood or made of various metals. The oldest book printed with wooden movable type was Records of Jingde County printed by Wang Zhen in 1298. In 1313 he published an account of his invention A method of making moveable wooden types for printing books.


A revolving typecase for wooden type in China, from Wang Zhen’s book published in 1313 Source: Wikimedia Commons

The oldest known book printed with metal moveable type is the two volume Jikji, a collection of excerpts from the analects of revered Buddhist monks, printed with metal type in Korea in 1377; that is at least seventy years before Gutenberg’s famous Bible. However, whereas 49 copies of Gutenberg’s Bible still exist, of which 21 are complete, only one copy of the second volume of the Jikji is still extant.


Korean movable type from 1377 used for the Jikji Source: Wikimedia Commons


Jikji or “Selected Teachings of Buddhist Sages and Seon Masters”, published in 1377, Korea during the Goryeo Dynasty. Source: Wikimedia Commons

Even within Europe Gutenberg was not the first to use moveable type, with several people experimenting with varying system. However Gutenberg was the first to produce anything functional and in reality his greatest inventions were not so much moveable type as the printing press (he converted a wine press) and printing ink or to put it another way he didn’t just invent moveable type but the whole printing process.


Replica of the Gutenberg press at the International Printing Museum in Carson, California Source: Wikimedia Commons

Although extensive effort has been invested into the research on the topic, no evidence has been found of a technology transfer from East Asia to Europe and it is thought that Gutenberg’s was an independent (re)invention.

Although my account is itself only a sketch of the development of printing, both woodblock and moveable type ( I don’t even touch upon book (re)production before woodblock printing or after moveable type), my main argument is that the London Review of Books article in just making its invalid comparison between the Dunhuang Diamond Sūtra and Gutenberg’s Bible creates an inadequate and distorted impression of a long and complex historical process; an impression that uninformed readers will take away with them. A mythical historical meme has been created “the first printed book is the Dunhuang Diamond Sūtra and not the Gutenberg Bible” to replace the Eurocentric myth that Gutenberg invented movable type printing and his Bible is the earliest printed book. If writing short popular historical pieces for the general public we should avoid simplistic descriptions and thereby the risk of creating myths rather than transmitting real knowledge.



Filed under Early Scientific Publishing, History of Technology, Uncategorized

The telescope – claims and counterclaims

Sometime between the 25thand 29thof September 410 years ago Hans Lipperhey, a spectacle maker from Middelburg in Zeeland, gave the earliest known public demonstration of the telescope to Maurits of Nausau and assembled company at a peace conference in Den Hague.


Source: Wikimedia Commons

His demonstration was recorded in a French newsletter, AMBASSADES DV ROY DE SIAM ENVOYE’ A L’ECELence du Prince Maurice, arriué à la Haye le 10. Septemb. 1608., recording the visit of the ambassador of the King of Siam (Thailand), who was also present at the demonstration.

A few days before the departure of Spinola from The Hague a spectacle-maker from Middelburg, a humble man, very religious & pious, offered His Excellency certain glasses as a present, by which one is able to trace & observe clearly objects at a distance of three or four miles, as if there is a distance as little as one hundred footsteps. From the tower of The Hague with the said glasses one can observe clearly the clock on the tower of Delft, & the windows of the Church of Leiden, despite the fact that one of the said towns is at a distance of one & a half hours and the other one at three and a half hours walking distance. The States-General were already well informed about this and sent them to His Excellency to show, adding that with these glasses one could observe the impostures of the enemy. Spinola also saw them with great astonishment & told Prince Hendrik; from this moment on I will not be safe anymore, because you can observe me from afar. Whereupon the said Prince answered: we will prohibit our people to shoot at you. The craftsman who has manufactured the said glasses has received three hundred écu & he will receive more on condition that he will tell nobody about the said proficiency, which he promised with most pleasure as he doesn’t want the enemy will be able to use this, 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 very 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.[1]

This was not however the first written account of Lipperhey’s new invention. The Councillors of Zeeland had given him a letter of introduction, dated 25 September, to the States-General in Den Hague, it begins:

The bearer of this, who claims to have a certain device, by means of which all things at a great distance can be seen as if they were nearby, by looking through glasses which he claims to be a new invention, would like to communicate the same to His Excellency [Prince Maurits]. Your Honour will please recommend him to His Excellency, and, as the occasion arises, be helpful to him according to what you think of the device…[2]

On 2 October 1608, Lipperhey submitted an application for a patent for his device to the States-General, from here on things, which had looked so promising for our humble spectacle-maker from Middelburg started to turn decidedly pear shaped.


Hans Lipperhey’s unsuccessfully patent request Source: Wikimedia Commons

On 14 October 1608, an, until now, unidentified young man offered to sell a telescope to the Councillors of Zeeland, who dutifully informed the States-General of this new development. On 15 October the States-General received a letter from Jacob Adriaenszoon (after 1571–1628) called Metius, a spectacle-maker from Alkmaar also requesting a patent for his instrument on which he had been working for two years and which, so he claimed, was a least as good as the instrument from Middelburg. Given these developments, telescopes were apparently available on every street corner, the States-General denied Lipperhey his desired patent but they did commission him to make six pairs of binoculars for a total of 900 guilders, a very large sum. Interestingly they demanded that the lenses be made of rock crystal rather than glass, because of the poor quality of the glass lenses, something that would remain a problem for telescope makers throughout the seventeenth century.

The problem with who actually invented the telescope does not end there. In his Mundus Jovialis, published in 1614, Simon Marius, one of the earliest telescopic astronomers, recounts how his patron Johan Philip Fuchs von Bimbach was offered a telescope at the Autumn Frankfurt Fair in 1608.


Engraved image of Simon Marius (1573-1624), from his book Mundus Iovialis, 1614 Source: Houghton Library via Wikimedia Commons

He didn’t purchase the proffered instrument because one of the lenses was cracked and the asking price was apparently too high. In many accounts of the invention of the telescope, this story is used as an illustration of how fast the new invention spread after Lipperhey’s unveiling in Den Hague. However, there is a major problem here; the Autumn Fair in Frankfurt in 1608 took place before Lipperhey’s demonstration. We have yet another unclear source for the ‘first telescope’.


Hans Philipp Fuchs von Bimbach Source: Wikimedia Commons

Up till 2008 it had become common practice to claim that the seller in Frankfurt and the unknown young man in Middelburg were one and the same and identified as Zacharias Janssen (1585-pre. 1632) and that he and not Lipperhey was the true inventor of the telescope and for good measure also the microscope.  How this all came about is almost Byzantine.


Zacharias Janssen Source: Wikimedia Commons

In 1655, the French scholar Pierre Borel (c. 1620–1671) published the first full history of the invention of the telescope, De vero telescopii inventore.


De vero telescopii inventore 1665 Title page Source

In his book he followed the account of the Dutch Ambassador to France, Willem Boreel (1591–1668). Born in Middelburg, Boreel had memories of having met the inventor of the telescope in 1610. Not sure of his memory forty-five years later he wrote to a local magistrate in Middelburg to investigate the matter. The magistrate interviewed a then unknown spectacle-maker Johannes Zachariassen, the son of Zacharias Janssen. Johannes claimed that his father and his grandfather had invented the microscope and telescope in 1590. Johannes would also tell a similar story to Isaac Beeckman, when he was teaching him lens grinding, also claiming that he and his father had also invented the long, i.e. astronomical, telescope in 1618. Boreel confirmed Johannes account as agreeing with his memories and Borel’s account that Zacharias Janssen and not Hans Lipperhey was the true inventor of the telescope.


Portrait of Pierre Borel by Jacques Pauthe Source: Wikimedia Commons

The last of Johannes’ claims is easily disposed of because it was Johannes Kepler, who first described the astronomical telescope in his Dioptrice in 1611. As to the other claim in 1590 Johannes’ grandfather was already dead and his father Zacharias was a mere four or five years old. These objections were simply swept aside over the years and Janssen’s invention simply moved forward to 1604 another date claimed by Johannes. However modern research by Huib Zuidervaart into the life of Zacharias Janssen have shown the first contact that he had with lens grinding or spectacle-making was when he became guardian the children of another spectacle-maker ‘Lowys Lowyssen, geseyt Henricxen brilmakers’. There is no other evidence that Zacharias was ever a spectacle-maker.[3]

The unknown youth in Middelburg and the telescope seller in Frankfurt remain unknown and probably forever unknowable.

News of the wonderful new invention spread really fast throughout Europe with telescopes on sale as novelties in Paris by the early summer 1609. The enthusiasm with which the new invention was greeted and the speed with which it spread throughout Europe rather puts the lie to all the competing theories that the telescope was already invented by (insert your favourite candidate) at some date before Lipperhey’s first demonstration. If it had been, we would certainly have heard about it. As far as we know, the first astronomer to make observations with the new instrument was Thomas Harriot, who drew a sketch of the moon observed with a six-power telescope dated 26 July 1609 os (5 August ns).


Harriot’s sketch of the moon 1609

Following on to his encounter with a telescope at the Frankfurt Fair, Fuchs von Bimbach together with Simon Marius obtained, with some difficulty, suitable lenses and the two of them constructed their own telescope. Simon Marius began his own astronomical observations sometime also in 1609. Galileo Galilei heard of the telescope through his friend Paolo Sarpi and it is now thought that his claim that he devised the construction of his telescope purely on the basis of having heard of it is not true and that he had in fact seen and handled a telescope before he began his own efforts at construction.


Galileo Galilei. Portrait by Ottavio Leoni Marucelliana Source: Wikimedia Commons

Galilei/ Fernrohre / Aufnahme

Galileo’s telescopes Source: Wikimedia Commons

Galileo, ever on the look out to make a quick buck and further his career, first marketed ‘his invention’ to the civil authorities, demonstrating a six-power telescope to the aristocrats of Venice 21 August 1609. On the 24thof the month he presented said telescope formally to the Doge and Senate of Venice. The following day the authorities granted him a lifetime contract as professor of mathematics at the university with the extraordinary salary of 1,000 florins p.a. with however the condition that he would never receive another pay rise. The Senate was apparently more than somewhat miffed when they discovered that the telescope was not the invention of their talented mathematics professor but was readily available on every street corner in Europe to knockdown prices. Galileo repaid their generosity by beginning plans to leave Venice and return to Florence.

We don’t know for certain when Galileo began his astronomical observations but we do know that he was an exceptionally talented observer and was soon viewing the skies on clear nights with a twenty-power instrument of his own construction. On 7 January 1610 he knew he had hit the jackpot when he first observed three of the moons of Jupiter. Simon Marius made the same discovery one day later on 8 January. More accurately he realised he had hit the jackpot only a couple of days later when it became clear that what he had discovered were satellites and not fixed stars. Marius waited four years before he published his discovery, Galileo didn’t! He immediately changed from Italian to Latin in his observing blog log and began making plans to publish his telescopic observation before he could be beaten to the gun by some unknown rival.

He decided to dedicate his planned publication to Cosimo II De’ Medici Fourth Grand Duke of Tuscany and started negotiations with the Tuscan Court over which names/names they would prefer for the newly discovered moons. In the end the term Medicean Stars was decided upon and Galileo’s Sidereus Nuncius was published with a preface dated forth day before the Ides of March 1610, that’s 12 March in modern money.


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

Seldom has a book hit the streets with such an impact. It truly marks the beginning of a new epoch in the history of astronomy and a new phase in the life of its author. Galileo got what he was angling for, he was appointed court mathematicus and philosophicus to the court in Florence and given a professorship at the university without teaching obligations but with a salary of 1,000 florins p.a.

The very poor quality of the glass available to make lenses and the errors in grinding and polishing made it very difficult for observers to see anything at all through the early telescopes, a problem that would continue to plague telescope users throughout the seventeenth century. There were as many claims made for discoveries that didn’t exist as for real ones.  All of this made it difficult for others to confirm Galileo’s spectacular claims. In the end the Jesuit astronomers of the Collegio Romano in Rome were able with much effort and many setbacks to confirm all of his discoveries. In 1611 he made a triumphant tour of Rome, which included a celebration banquet put on by the Jesuits at the Collegio. At a second banquet put on by Prince Frederico Cesi, founder and President of the Accademia dei Lincae of which Galileo would become a member, the telescope first received its name, in Greek teleskopos.

Another central problem in the first months of telescopic astronomical observation was that there existed no scientific explanation of how or why the telescope functions. This allowed critics to reject the discoveries as imaginary artefacts produced by the instrument itself. The man who came to the rescue was Johannes Kepler. Already in 1604 in his Ad Vitellionem Paralipomena Astronomiae pars optica, Kepler had published the first explanation of how lenses focus light rays and how eyeglasses work to compensate for short and long sightedness so he already had a head start on explaining how the telescope functions.

Francesco Maurolico (1494–1575) had covered much of the same ground in his Theoremata de lumine et umbra earlier than Kepler but this work was only published posthumously in 1611, so the priority goes to Kepler.


Source: Wikimedia Common


In 1611 Kepler published his very quickly written Diotrice, in which he covered the path of light rays through single lenses and then through lens combinations. In this extraordinary work he covers the Dutch or Galilean telescope, convex objective–concave eyepiece, the astronomical or Keplerian telescope, convex objective–convex eyepiece, the terrestrial telescope, convex objective–convex eyepiece–convex–field–lens to invert image, and finally for good measure the telephoto lens! Galileo’s response to this masterpiece in the history of geometrical optics was that it was unreadable!


Source: Wikimedia Commons

One small footnote to the whole who–invented–what story is that Kepler attributed the invention of the telescope to Giambattista della Porta (1535?–1615).


Giambattista della Porta Source: Wikimedia Commons

Della Porta did indeed describe the magnifying effect of the lens combination of the Dutch telescope in his Magiae Naturalis(various editions 1558 to 1589).

With a concave you shall see small things afar off, very clearly; with a convex, things neerer to be greater, but more obscurely: if you know how to fit them both together, you shall see both things afar off, and things neer hand, both greater and clearly.

He provided a primitive sketch in a letter to Prince Cesi in 1609.

Della Porta Telescope Sketch

Kepler assumed that the Dutch spectacle-maker, he didn’t know Lipperhey’s name, had somehow learnt of della Porta’s idea and put it into practice. It is more probable that della Porta was actually describing some sort of compound magnifying glass rather than a telescope and that Lipperhey had no idea of della Porta’s work.

Despite the confusion that surrounds the origins of the telescope, today most historians attribute the honours to Hans Lipperhey, whose demonstration set the ball rolling. We have come a long way since Lipperhey demonstrated his simple invention to Prince Maurits in Den Hague. I don’t suppose the humble spectacle–maker from Middelburg could have conceived the revolution in astronomy he set in motion on that day four hundred and ten years ago.

[1]Embassies of the King of Siam Sent to His Excellency Prince Maurits Arrived in The Hague on 10 September 1608,Transcribed from the French original, translated intoEnglish and Dutch, introduced by Henk Zoomers and edited by Huib Zuidervaart after a copy in the Louwman Collection of Historic Telescopes, Wassenaar, 2008 pp. 48-49 (original pagination: 9-11)

[2]Taken from Fred Watson, Stargazer: the life and times of the Telescope, Da Capo Press, Cambridge MA, 2005

[3]For more details of the Dutch story of the invention of the telescope see Huib J. Zuidervaart, The ‘true inventor’ of the telescope. A survey of 400 years of debate, in The origins of the telescope, ed. Albert van Helden, Sven Dupré, Rob van Gent, Huib Zuidervaart, KNAW Press, Amsterdam, 2010


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