Category Archives: History of Mathematics

Renaissance Science – XLIX

The mathematisation of science is considered to be one of the principle defining characteristics of the so-called scientific revolution in the seventeenth century. Knowledge presentation on the European, medieval universities was predominantly Aristotelian in nature and Aristotle was dismissive of mathematics. He argued that the objects of mathematics were not real and therefore mathematics could not produce knowledge (episteme/scientia). He made an exception for the so-called mixed disciplines: astronomy, geometrical optics, and statics. These were, however, merely functionally descriptive, and not knowledge. So, mathematical astronomy described how to determine the positions of celestial bodies at a given point in time, but it was non-mathematical cosmology that described the true nature of those celestial bodies. Knowledge production and knowledge acquisition was, for Aristotle and those who adopted his philosophy, non-mathematical.

With just a relatively superficial examination, it is very clear that the new knowledge delivered up in astronomy, physics etc in the seventeenth century was very mathematical, just consider the title of Newton’s magnum opus, Philosophiæ Naturalis Principia Mathematica (The Mathematical Principles of Natural Philosophy), something major had changed and two central questions for the historian of science are what and why? 

When I first started learning the history and philosophy of science several decades ago, there was a standard pat answer to this brace of questions. It was stated that there had been a change in philosophical systems underlying knowledge acquisition, Aristotelian philosophy and been replaced by a mathematical neo-Platonic philosophy; Plato had, according to the legend, famously the dictum, May no one ignorant of Geometry enter here Inscribed above the entrance to his school, The Academy. The belief that the mathematisation of science was driven by a Platonic renaissance was probably strengthened by the fact that the title page of Copernicus’ De Revolutionibus, the book that supposedly signalled the start of the scientific revolution, carried the same dictum. In fact, there is no evidence in Greek literature from the entire time that The Academy was open that the dictum existed. It was first mentioned by John Philoponus (c. 490­–c. 570) after Justinian had ordered The Academy closed in 529. De Revolutionibus is also not in anyway Platonic. 

To be fair to the proposers of the Plato replaced Aristotle thesis, Plato’s philosophy was definitively more mathematical than Aristotle’s and there was a neo-Platonic revival during the Renaissance, but it was more the esoteric and mystical Plato rather than the mathematical Plato, as I’ve already outlined in an earlier episode in this series.

So, what did drive the mathematisation? As already explained in explained in earlier episodes there were major expansions and developments in astronomy, cartography, surveying, and navigation starting in the fifteenth century during the Renaissance. All four disciplines demanded an intensive use of geometry and especially trigonometry. This can be seen in the publication of the first printed edition of Euclid by Erhard Ratdolt (1442–1528) in 1482, which was followed by significant printed translations in the vernacular throughout Europe.

A page with marginalia from the first printed edition of Euclid’s Elements, printed by Erhard Ratdolt in 1482
Folger Shakespeare Library Digital Image Collection
Source: Wikimedia Commons

In trigonometry, Johannes Petreius (c. 1497–1550) published Regiomontanus’ De triangulis omnimodis (On Triangles of All Kinds), edited by Johannes Schöner, in 1533. This was the first almost complete account of trigonometry published in Europe, the only thing that was missing was the tangent, but Regiomontanus had included the tangent in his earlier Tabula directionum, written in 1467 but first published in print in 1490. Regiomontanus’ trigonometry was followed by several important volumes on the topic during the sixteenth century. 


These areas of mathematical development were however for the Aristotelian academics at the universities not scientia and the mathematical practitioners, who did the mathematics were not considered to be academics but mere craftsmen. However, the widening reliance on mathematics in what had become important political areas of Renaissance society did much to raise the general status of mathematics.

Another area where a mathematical subdiscipline was on the advance was algebra, the basis for the analytical mathematics that would become so important in the seventeenth century. Already introduced in the twelfth century, with the translation of al-Khwarizmi’s text on the Hindu-Arabic number system into Latin, Algoritmi de numero Indorum along with the book that gave algebra its name, al-Kitāb al-Mukhtaṣar fī Ḥisāb al-Jabr wal-Muqābalah. It initially had minimal impact. However, reintroduced in the next century by Leonardo Pisano, with his Liber Abbaci, and although the acceptance was slow, only beginning to accelerate with the introduction of double entry bookkeeping at the end of the thirteenth century and beginning of the fourteenth. By the sixteenth century many abbaco schools (scuole d’abbaco or botteghe d’abbco) had been established throughout Europe teaching the Hindu-Arabic number system and algebra to apprentices using Libri d’abbaco, (abbacus books). In fact, the first ever printed mathematics book was an abbacus book, the so-called Treviso Arithmetic or Arte dell’Abbaco written in vernacular Venetian and published in Treviso in 1478. 

Once again, however, what was being taught here was not an academic discipline, which could generate scientia, but commercial arithmetic, very useful for an increasing commercial Europe dependent on extensive trade but not for the acquisition of academic knowledge. This began to change slowly in the sixteenth century beginning with the Summa de arithmetica, geometria, proportioni et proportionalita of Luca Pacioli (c. 1447–1517) published in 1496, still a book of practical mathematics and so not academic, but one which contained the false claim that there could not be a general solution of the cubic equation. This led on to Scipione del Ferro (1465–1526) discovering such a solution, Tartaglia (c. 1499–1557) rediscovering it and Gerolamo Cardano (1501–1576) seducing Tartaglia into revealing his solution and then publishing it in his Ars Magna. All of which I have outlined in more detail here. Cardano’s Ars magna, published in Nürnberg in 1545 by Johannes Petreius, has been called the first modern mathematics book, a term I don’t particularly like, but it did bring algebra into the world of academia, although it still wasn’t considered to be knowledge producing.


So, how did the change in status of mathematics on the universities come about and who was responsible for it if it wasn’t Plato? The change was brought about by Italian, humanist scholars in the sixteenth century and the responsibility lies not with a philosopher but with a mathematician, Archimedes. 

Bronze statue of Archimedes in Syracuse Source: Wikimedia Commons

Archimedes of Syracuse (c.287–c. 212 BCE) mathematician, physicist, engineer, and inventor is one of the most well-known figures in the entire history of science. Truly brilliant in a range of fields of study and immersed in a cloud of myths and legends. He is famous for the machines he invented and a legend for alleged machines he constructed to defend his hometown of Syracuse against the Romans. It is these war machines and the myth of his death at the hands of a Roman soldier that dominate the accounts of his life all written posthumously in antiquity. His mathematical work, which is what interest us here, remained largely unknown in antiquity. There only began to become known in the Early Middle Ages but, although translated into Arabic by Thābit ibn Qurra (836–901) and from there into Latin by Gerard of Cremona (c. 1114–1187) and again directly from Geek into Latin by William of Moerbeke (c. 1215–1286) and once more by Iacobus Cremonnensis (c. 1400–c. 1454), his work received very little attention in the Middle Ages.

Beginning, already in the fifteenth century, Renaissance humanist began to seriously re-evaluate the leading Greek mathematicians, in particular Euclid and Archimedes. Euclidian geometry was playing a much greater role in the evolving optics, in particular linear perspective, than it had ever played on the medieval universities. This led, as already noted above, to the publication of the first printed edition of The Elements, by Erhard Ratdolt, in 1482. Interestingly, the manuscript that Ratdolt used for edition was one that Regiomontanus (1436–1476) had brought with him to Nürnberg, where he established the world’s first scientific published endeavour, intending to publish it himself, as he announced in his published catalogue of intended publications. Unfortunately, he died before he could print most of this extensive catalogue of scientific and mathematical texts. 

This catalogue also included a manuscript of the works of Archimedes in the Latin translation of Iacobus Cremonnensis, which also fell foul of the Franconian mathematician’s early death. This manuscript would eventually be published in Basel, together with a Greek original brought from Rome by Willibald Pirckheimer (1470–1530), in a bilingual edition of the works edited by the Nürnberger theologian, humanist, and mathematician, Thomas Venatorius (1488–1551), in 1544. 

Venatorius’ edition of the works of Archimedes Source

The Italian astrologer, astronomer, and mathematician, Luca Gaurico (1475–1558), had published Archimedes’ works On the Parabola and On the Circle in the Latin translation by William of Moerbeke in 1503. Niccolò Fontana Tartaglia, who had published an Italian translation of The Elements in 1543, also published On the ParabolaOn the CircleCentres of Gravity, and On Floating Bodies in the Moerbeke translation in 1543. Later he would publish translation into Italian of these works, some of which appeared posthumously. Unlike, other later, Italian mathematicians, Tartaglia did not incorporate much of Archimedes’ work into his own highly influential, original Nova Scientia (1537), a mathematical work that did deliver, as the title says, scientia or knowledge. It is difficult to say how much Tartaglia was influenced by Archimedes in his approach to physics. 

Opera Archimedis Syracusani philosophi et mathematici ingeniosissimi per Nicolaum Tartaleam … (facsimile) Source

We have already seen in the episode on hydrostatics how Archimedes work On Floating Bodies, informed and influenced the work of both Tartaglia’s one time student, Giambattista Benedetti (1530–1590), and the engineer, Simon Stevin (1448–1620) in the Netherlands in their work on hydrostatics and on the laws of fall. As I have also outlined in great detail, Archimedes work on statics had a major influence on the Italian mathematicians of the so-called Urbino School. Federico Commandino (1509 – 1575), Guidobaldo dal Monte (1545 – 1607), and Bernardino Baldi (1553–1617), the first two also producing and publishing new improved translations of various of Archimedes work. Once again Simon Stevin also produced a major, Archimedes inspired work on statics. 

These mathematicians had, directly inspired, and heavily influenced by the work of Archimedes, now produced, in several fields, work that was indisputably scientia or knowledge by the use of mathematics and thus instigated the turn from Aristotelian philosophical knowledge to the mathematisation of knowledge production and this movement began to spread in the seventeenth century.

The Urbino School, in particular dal Monte, who was his patron, influenced Galileo, who openly declared that he had in his natural philosophy replaced Aristotle with Archimedes. Galileo’s pupils Vincenzo Viviani (1622–1703) and Evangelista Torricelli (1608–1647) followed his lead on this. Stevin’s work, written in Dutch was translated into Latin by Willebrord Snel (1580–1626) and heavily influenced the French natural philosophers such as, Marin Mersenne (1588–1648), who together with Pierre Gassendi (1592–1655) led the informal academic society, the Academia Parisiensis, a weekly gathering from 1633 onwards, which included the most important French, English and Dutch natural philosophers of the period. This group was of course also influenced by the work of Galileo. 

It was not the thoughts of a philosopher, Plato, that pushed Aristotelian philosophy from its throne on the medieval university as the purveyor of factual knowledge of the real world and replaced it with a mathematics-based system, but the work of a mathematician, Archimedes. As the century progressed Euclid and Archimedes would in turn be replaced by the algebra-based analytical mathematics that would eventually develop into calculus, although also here the method of exhaustion first developed by Eudoxus of Cnidus (c. 408–c. 355 BCE), but popularised by Archimedes was the basis of the integral calculus half of the new mathematics.


Filed under History of Mathematics, History of science, Renaissance Science

Starting off Fibonacci year…

The HistSci-Hulk woke up briefly from his winter slumbers to cast a bleary eye over a piece by Katie Steckles on the web site SciLogs celebrating, what some are calling the Fibonacci New Year, because it starts with 1/1/23 the first four digits of the so-called Fibonacci sequence. It doesn’t really because the sequence correctly begins with a zero and Fibonacci began it with 1, 2 not 1, 1, 2.

“I bet she doesn’t point out that old Leo wasn’t the first to elucidate this sequence,” the grumpy beast muttered as rubbed the sleep out of his eyes. 

Surprisingly he was wrong, as Steckles does actually point out that the sequence first appeared historically in Indian grammatical studies of Sanskrit prosody. However, much to the annoyance of out grumpy friend, her second paragraph is loaded historical with historical errors.

Leonardo Fibonacci, also known as Leonardo of Pisa, was an Italian mathematician born circa 1170 CE, who – like many historical mathematicians – is primarily remembered for one book he wrote. 

His name was never Leonardo Fibonacci. He was Leonardo Pisano, which translates as Leonardo of Pisa. The name Fibonacci, which unfortunately has become universal, was created in the nineteenth century by a French historian. 

In Fibonacci’s case, the book was called “Liber Abaci” – literally, “The Book of the Abacus” – although it was actually presented as an alternative to the then-common use of abaci for calculation. 

Liber Abaci, which on the title page is actually spelt Liber Abbaci, although Leonardo uses both spellings in the text, has absolutely nothing to do with the abacus or counting board. Abbaci comes from the then Italian term for calculate or reckon and the correct translation of the title is Book of Calculations.

Published in 1202, this was the first European work covering Indian and Arabian mathematics, and introduced the idea of Hindu-Arabic numerals – the standard digits 0-9 with a decimal system we use today – to Europe for the first time.

This was not the first European work covering Indian and Arabian mathematics, that honour probably goes to the Latin translations of al-Khwarizmi’s On the Calculation with Hindu Numerals, (Arabic original c. 825), Latin Algoritmi de numero Indorum, al-Kindi’s On the Use of the Hindu Numerals (Arabic original c. 830), and al-Khwarizmi’s The Compendious Book on Calculation by Completion and Balancing (Arabic original c. 820) all of which were available in Europe earlier than the Liber Abbaci.

The Liber Abbaci was the first presentation of the Hindu-Arabic number system written by a European author, and had a greater impact than the Latin translations of the Arabic works, because it was presented as commercial arithmetic, leading to the abbacus schools and abbacus books to teach commercial arithmetic to apprentice traders in a Europe, when trading was increasing exponentially.

A minor but important point is that the digits for 0-9 introduced by Leonardo looked very different to the ones we know today.

Evolution of the digits 0-9 Source: Wikimedia Commons

Another minor point is that the digits for 0-9 had already been introduced in the tenth century by Gerbert d’Aurillac (c. 946–1003) but not the number system. He used them to label the counters on his abacus.

A more detailed post on the history of the Hindu-Arabic number system can be found here


Filed under History of Mathematics

Renaissance Science – XLVIII

Using the simplest and widest definition as to what constitutes a scientific instrument, it is literally impossible to say who first created, devised, used a scientific instrument or when and where they did it. My conjecture would be that the first scientific instrument was some sort of measuring device, a rod, or a cord to standardise a unit of measurement, almost certainly taken from the human body: a forearm, the length of a stride or pace, maybe a foot, a unit that we still use today. It is obviously that all the early great civilisation, Indus valley, Yellow River, Yangtze River, Fertile Crescent and so on, definitely used measuring devices, possibly observational devices, instruments to measure or lay out angles, simple compasses to construct circles, all of them probably as much to do with architecture and surveying, as with anything we might now label science.

This is the Royal cubit rod of Amenemope – a 3320-year-old measuring rod which revealed that Egyptians used units of measurement taken from the human body. The basic unit was the cubit – the length from the elbow to the tip of the middle finger, about 45cm. Source: British Museum

Did the early astronomers in China, India, Babylon use some sorts of instruments to help them make their observations? We know that later people used sighting tubes, like a telescope without the lenses, to improve the quality of their observations, did those first astronomers already use something similar. Simple answer, we don’t really know, we can only speculate. We do know that Indian astronomers used a quadrant in their observation of solar eclipses around 1000 BCE. 

Turning to the Ancient Greeks we initially have a similar lack of knowledge. The first truly major Greek astronomer Hipparkhos (c. 190–c. 120 BCE) (Latin Hipparchus) definitely used astronomical instruments but we have no direct account of his having done so. Our minimal information of his instruments comes from later astronomers, such as Ptolemaios (c. 100–c. 170 CE). Ptolemaios tells us in his Mathēmatikē Syntaxis aka Almagest that Hipparkhos made observations with an equatorial ring.

The easiest way to understand the use of an equatorial ring is to imagine a ring placed vertically in the east-west plane at the Earth’s equator. At the time of the equinoxes, the Sun will rise precisely in the east, move across the zenith, and set precisely in the west. Throughout the day, the bottom half of the ring will be in the shadow cast by the top half of the ring. On other days of the year, the Sun passes to the north or south of the ring, and will illuminate the bottom half. For latitudes away from the equator, the ring merely needs to be placed at the correct angle in the equatorial plane. At the Earth’s poles, the ring would be horizontal. Source: Wikipedia

At another point in the book Ptolemaios talks of making observations with an armillary sphere and compares his observations with those of Hipparkhos, leading some to think that Hipparkhos also used an armillary sphere. Toomer in his translation of the Almagest say there is no foundation for this speculation and that Hipparkhos probably used a dioptra. [1]

Ptolemaios mentions four astronomical instruments in his book, all of which are for measuring angles: 

1) A double ring device and

Toomer p. 61

2) a quadrant both used to determine the inclination of the ecliptic.

Toomer p. 62

3) The armillary sphere, which he confusingly calls an astrolabe, used to determine sun-moon configurations. 

Toomer p. 218

4) His parallactic rulers, used to determine the moon’s parallax, which was called a triquetrum in the Middle Ages. 

Toomer p. 245

Ptolemaios almost certainly also used a dioptra a simple predecessor to the theodolite used for measuring angles both in astronomy and in surveying. As I outlined in the post on surveying, ancient cultures were also using instruments to carry out land measuring.

Graphic reconstruction of the dioptra, by Venturi, in 1814. (An incorrect interpretation of Heron’s description) Source: Wikimedia Commons

Around the same time as the armillary sphere began to emerge in ancient Greece it also began to emerge in China, with the earliest single ring device probably being used in the first century BCE. By the second century CE the complete armillary sphere had evolved ring by ring. When the armillary sphere first evolved in India is not known, but it was in full used by the time of Āryabhata in the fifth century CE.

Armillary sphere at Beijing Ancient Observatory, replica of an original from the Ming Dynasty

A parallel development to the armillary sphere was the celestial globe, a globe of the heavens marked with the constellations. In Greece celestial globes predate Ptolemaios but none of the early ones have survived.  In his Almagest, Ptolemaios gives instruction on how to produce celestial globes. Chinese celestial globes also developed around the time of their armillary spheres but, once again, none of the early ones have survived. As with everything else astronomical, the earliest surveying evidence for celestial globes in India is much later than Greece or China.

The Farnese Atlas holding a celestial globe is the oldest known surviving celestial globe dating from the second century CE Source: Wikimedia Commons

In late antiquity the astrolabe emerged, its origins are still not really clear. Ptolemaios published a text on the planisphere, the stereographic projection used to create the climata in an astrolabe and still used by astronomers for star charts today. The earliest references to the astrolabe itself are from Theon of Alexandria (c. 335–c. 414 CE). All earlier claims to existence or usage of astrolabes are speculative. No astrolabes from antiquity are known to have survived. The earliest surviving astrolabe is an Islamic instrument dated AH 315 (927-28 CE).

North African, 10th century AD, Planispheric Astrolabe Khalili Collection via Wikimedia Commons

Late Antiquity and the Early Middle Ages saw a steady decline in the mathematical sciences and with it a decline in the production and use of most scientific instruments in Europe until the disappeared almost completely. 

When the rapidly expanding Arabic Empire began filing their thirst for knowledge across a wide range of subjects by absorbing it from Greek, Indian and Chinese sources, as well as the mathematical disciplines they also took on board the scientific instruments. They developed and perfected the astrolabe, producing hundreds of both beautiful and practical multifunctional instruments. 

As well large-scale astronomical quadrants they produced four different types of handheld instruments. In the ninth century, the sine or sinical quadrant for measuring celestial angles and for doing trigonometrical calculations was developed by Muḥammad ibn Mūsā al-Khwārizmī. In the fourteenth century, the universal (shakkāzīya) quadrant used for solving astronomical problems for any latitude. Like astrolabes, quadrants are latitude dependent and unlike astrolabes do not have exchangeable climata. Origin unknown, but the oldest known example is from 1300, is the horary quadrant, which enables the uses to determine the time using the sun. An equal hours horary quadrant is latitude dependent, but an unequal hours one can be used anywhere, but its use entails calculations. Again, origin unknown, is the astrolabe quadrant, basically a reduced astrolabe in quadrant form. There are extant examples from twelfth century Egypt and fourteenth century Syria.

Horary quadrant for a latitude of about 51.5° as depicted in an instructional text of 1744: To find the Hour of the Day: Lay the thread just upon the Day of the Month, then hold it till you slip the small Bead or Pin-head [along the thread] to rest on one of the 12 o’Clock Lines; then let the Sun shine from the Sight G to the other at D, the Plummet hanging at liberty, the Bead will rest on the Hour of the Day. Source: Wikimedia Commons
Astrolabic quadrant, made of brass; made for latitude 33 degrees 30 minutes (i.e. Damascus); inscription on the front saying that the quadrant was made for the ‘muwaqqit’ (literally: the timekeeper) of the Great Umayyad Mosque of Damascus. AH 734 (1333-1334 CE) British Museum

Islamicate astronomers began making celestial globes in the tenth century and it is thought that al-Sufi’s Book of the Constellations was a major source for this development. However, the oldest surviving Islamic celestial globe made by Ibrahim Ibn Saîd al-Sahlì in Valencia in the eleventh century show no awareness of the forty-eight Greek constellations of al-Sufi’s book.

Islamicate mathematical scholars developed and used many scientific instruments and when the developments in the mathematical sciences that they had made began to filter into Europe during the twelfth century scientific renaissance those instruments also began to become known in Europe. For example, the earliest astrolabes to appear in Europe were on the Iberian Peninsula, whilst it was still under Islamic occupation.  

Canterbury Astrolabe Quadrant 1388 Source Wikimedia Commons
Astrolabe of Jean Fusoris, made in Paris, 1400 Source: Wikimedia Commons

The medieval period in Europe saw a gradual increase in the use of scientific instruments, both imported and locally manufactured, but the use was still comparatively low level. There was some innovation, for example the French Jewish scholar, Levi ben Geshon (1288–1344), published the first description of the cross staff or Jacob’s staff, used in astronomy, surveying, and navigation, in his Book of the Wars of the Lord (originally in Hebrew but also translated into Latin). 

…of a staff of 4.5 feet (1.4 m) long and about one inch (2.5 cm) wide, with six or seven perforated tablets which could slide along the staff, each tablet being an integral fraction of the staff length to facilitate calculation, used to measure the distance between stars or planets, and the altitudes and diameters of the Sun, Moon and stars

A Jacob’s staff, from John Sellers’ Practical Navigation (1672) Source: Wikimedia Commons

Also, the magnetic compass came into use in Europe in the twelfth century, first mentioned by Alexander Neckam (1157–1217) in his De naturis rerum at the end of the century.

The sailors, moreover, as they sail over the sea, when in cloudy whether they can no longer profit by the light of the sun, or when the world is wrapped up in the darkness of the shades of night, and they are ignorant to what point of the compass their ship’s course is directed, they touch the magnet with a needle, which (the needle) is whirled round in a circle until, when its motion ceases, its point looks direct to the north.

Petrus Pereginus (fl. 1269) gave detailed descriptions of both the floating compass and the dry compass in his Epistola de magnete

However, it was first in the Renaissance that a widespread and thriving culture of scientific instrument design, manufacture, and usage really developed. The steep increase in scientific instrument culture was driving by the substantial parallel developments in astronomy, navigation, surveying, and cartography that began around fourteen hundred that I have already outlined in previous episodes of this series. Renaissance scientific instrument culture is too large a topic to cover in detail in one blog post, so I’ll only do a sketch of some major points and themes with several links to other earlier related posts.

Already, the first Viennese School of Mathematics, which was heavily involved in the development of both astronomy and cartography was also a source of scientific instrument design and manufacture.Johannes von Gmunden (c. 1380–1442) had a notable collection of instruments including an Albion, a multipurpose instrument conceived by Richard of Wallingford (1292–1336).

Albion front side Source: Seb Falk’s Twitter feed
Albion rear Source: Seb Falk’s Twitter feed

Georg von Peuerbach (1423–1461) produced several instruments most notably the earliest portable sundial marked for magnetic declination.

Folding sundial by Georg von Peuerbach

His pupil Regiomontanus (1436–1476) wrote a tract on the construction and use of the astrolabe and there is an extant instrument from 1462 dedicated to Cardinal Bessarion and signed IOHANNES, which is assumed to have been made by him. At least eleven other Regiomontanus style astrolabes from the fifteenth century are known.

Regiomontanus style astrolabe Source: Wikimedia Commons

Elements of his design were adopted by both Johannes Stöffler (1452–1531), the first professor of astronomy at the University of Tübingen, and by the Nürnberger mathematicus Georg Hartmann (1489–1564).

Stöffler also made celestial globes and an astronomical clock.

Celestial Globe, Johannes Stöffler, 1493; Landesmuseum Württemberg Source: Wikimedia Commons

Mechanical astronomical clocks began to emerge in Europe in the fourteenth century, but it would not be until the end of the sixteenth century that mechanical clocks became accurate enough to be used as scientific instruments. The earliest clockmaker, who reached this level of accuracy being the Swiss instrument maker, Jost Bürgi (1552–1632)

Bürgi made numerous highly elaborate and very decorative mechanical clocks, mechanised globes and mechanised armillary spheres that were more collectors items for rich patrons rather than practical instruments.

Bürgi Quartz Clock 1622-27
Source: Swiss Physical Society

This illustrates another driving force behind the Renaissance scientific instrument culture. The Renaissance mathematicus rated fairly low in the academical hierarchy, actually viewed as a craftsman rather than an academic. This made finding paid work difficult and they were dependent of rich patrons amongst the European aristocracy. It became a standard method of winning the favour of a patron to design a new instrument, usually a modification of an existing one, making an elaborate example of it and presenting it to the potential patron. The birth of the curiosity cabinets, which often also included collections of high-end instruments was also a driving force behind the trend. Many leading instrument makers produced elaborate, high-class instruments for such collections. Imperial courts in Vienna, Prague, and Budapest employed court instrument makers. For example, Erasmus Habermel (c. 1538–1606) was an incredibly prolific instrument maker, who became instrument maker to Rudolf II. A probable relative Josua Habermel (fl. 1570) worked as an instrument maker in southern Germany, eventually moving to Prague, where he probably worked in the workshop of Erasmus.

 1594 armillary sphere by Erasmus Habermel of Prague.

Whereas from Theon onwards, astrolabes were unique, individual, instruments, very often beautiful ornaments as well as functioning instruments, Georg Hartmann was the first instrument maker go into serial production of astrolabes. Also, Hartmann, although he didn’t invent them, was a major producer of printed paper instruments. These could be cut out and mounted on wood to produce cheap, functional instruments for those who couldn’t afford the expensive metal ones. 

Hartmann astrolabe front
Hartmann astrolabe rear
Paper and Wood Astrolabe Hartmann Source: HSM Oxford

Hartmann lived and worked in Nürnberg, which as I have sketched in an earlier post, was for more than a century the scientific instrument capital of Europe with a massive produce of instruments of all sorts.

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

As well as astrolabes and his paper instruments Hartmann also produced printed globes, none of which have survived. Another Nürnberger mathematicus, Johannes Schöner (1477–1547) launched the printed pairs of terrestrial and celestial globes onto the market.

Celestial Globe by Johannes Schöner c. 1534 Source

His innovation was copied by Gemma Frisius (1508–1555), whose student Gerard Mercator (1512–1594) took up globe making on a large scale, launching the seventeenth century Dutch globe making industry. 

Gemma Frisius set up a workshop producing a range of scientific instruments together with his nephew (?) Gualterus Arsenius (c. 1530–c. 1580).  

Astronomical ring dial Gualterus Arsenius Source

In France, Oronce Fine (1494–1555), a rough contemporary, who was appointed professor at the Collège Royal, was also influenced by Schöner in his cartography and like the Nürnberger was a major instrument maker. In Italy, Egnatio Danti (1536–1586) the leading cosmographer was also the leading instrument maker. 

Egnation Danti, Astrolabe, ca. 1568, brass and wood. Florence, Museo di Storia della Scienza Source: Fiorani The Marvel of Maps p. 49

A major change during the Renaissance was the emergence, for the first time in Early Modern Europe, of large-scale astronomical observatories, Wilhelm IV (1532–1592) in Hessen-Kassel beginning in about 1560 and Tycho Brahe (1546–1601) on the Island of Hven beginning in 1575. Both men commissioned new instruments, many of which were substantially improved in comparison with their predecessors from antiquity.

Sternwarte im Astronomisch-Physikalischen Kabinett, Foto: MHK, Arno Hensmanns Reconstruction of Wilhelm’s observatory
Tycho Brahe, Armillary Sphere, 1581 Source
Tycho Brahe quadrant

Their lead was followed by others, the first Vatican observatory was established in the Gregorian Tower in 1580.

View on the Tower of Winds (Gregorian tower) in Vatican City (with the dome of Saint Peter’s Basilica in the background). Source: Wikimedia Commons

In the early seventeenth century, Leiden University in Holland established the first European university observatory and Christian Longomontanus (1562–1647), who had been Tycho’s chief assistant, established a university observatory in Copenhagen 

Drawing of Leiden Observatory in 1670, seen on top of the university building. Source: Wikimedia Commons
Copenhagen University Observatory Source: Wikimedia Commons

As in all things mathematical England lagged behind the continent but partial filled the deficit by importing instrument makers from the continent, the German Nicolas Kratzer (c. 1487–1550) and the Netherlander Thomas Gemini (c. 1510–1562). The first home grown instrument maker was Humfrey Cole (c. 1530­–1591). By the end of the sixteenth century, led by John Dee (1527–c. 1608), who studied in Louven with Frisius and Mercator, and Leonard Digges (c. 1515–c. 1559), a new generation of English instrument makers began to dominate the home market. These include Leonard’s son Thomas Digges (c. 1546–1595), William Bourne (c. 1535–1582), John Blagrave (d. 1611), Thomas Blundeville (c. 1522–c. 1606), Edward Wright (1561–1615), Emery Molyneux (d. 1598), Thomas Hood (1556–1620), Edmund Gunter (1581–1626) Benjamin Cole (1695–1766), William Oughtred (1574–1660), and others.

The Renaissance also saw a large amount of innovation in scientific instruments. The Greek and Chinese armillary spheres were large observational instruments, but the Renaissance armillary sphere was a table top instrument conceived to teach the basic of astronomy.

Armillary Sphere by Carlo Plato, Rome, 1588 Museum of the History of Science

In navigation the Renaissance saw the invention various variations of the backstaff, to determine solar altitudes.

Davis quadrant (backstaff), made in 1765 by Johannes Van Keulen. On display at the Musée national de la Marine in Paris. Source: Wikimedia Commons

Also new for the same purpose was the mariner’s astrolabe.

Mariner’s Astrolabe c. 1600 Source: Wikimedia Commons

Edmund Gunter (1581–1626) invented the Gunter scale or rule a multiple scale (logarithmic, trigonometrical) used to solve navigation calculation just using dividers.

Gunter scale front
Gunter scale back Source

William Oughtred (1574–1660) combined two Gunter scales to produce the slide rule.

New in surveying were the surveyor’s chain,

A Gunter chain photographed at Campus Martius Museum. Source: Wikimedia Commons

the plane table,

Surveying with plane table and surveyor’s chain

the theodolite

Theodolite 1590 Source:

and the circumferentor.

18th century circumferentor

All of which were of course also used in cartography. Another Renaissance innovation was sets of drawing instruments for the cartographical, navigational etc draughtsmen.

Drawing instruments Bartholomew Newsum, London c. 1570 Source

The biggest innovation in instruments in the Renaissance, and within its context one of the biggest instrument innovation in history, were of course the telescope and the microscope, the first scientific instruments that not only aided observations but increased human perception enabling researchers to perceive things that were previously hidden from sight. Here is a blog post over the complex story of the origins of the telescope and one over the unclear origins of the microscope.

The Renaissance can be viewed as the period when instrumental science began to come of age. 

[1] The information on Ptolemaios’ instruments and the diagrams are taken from Ptolemy’s Almagest, translated and annotated by G. J. Toomer, Princeton Paperbacks, 1998


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

God made all things by measure, number and weight[1]

God made all things by measure, number and weight[1]

The first history of science, history of mathematics book I ever read was Lancelot Hogben’s Man Must Measure: The Wonderful World of Mathematics, when I was about six years old.

It almost certainly belonged to my older brother, who was six years older than I. This didn’t matter, everybody in our house had books and everybody could and did read everybody’s books. We were a household of readers. I got my first library card at three; there were weekly family excursions to the village library. But I digress.

It is seldom, when people discuss the history of mathematics for them to think about how or where it all begins. It begins with questions like how much? How many? How big? How small? How long? How short? How far? How near? All of these questions imply counting, comparison, and measurement. The need to quantify, to measure lies at the beginning of all systems of mathematics. The histories of mathematics, science, and technology all have a strong stream of mensuration, i.e., the act or process of measuring, running through them. Basically, without measurement they wouldn’t exist. 

Throughout history measuring and measurement have also played a significant role in politics, often leading to political disputes. In modern history there have been at least three well known cases. The original introduction of the metric system during the French revolution, the battle of the systems, metric contra imperialism, during the nineteenth century, and most recently the bizarre wish of the supporters of Brexit to reintroduce the imperial system into the UK in their desire to distance themselves as far as possible from the evil EU. 

It was with some anticipation that I greeted the news that James Vincent had written and published Beyond MeasureThe Hidden History of Measurement.[2] Vincent’s book is not actually a history of measurement on a nuts and bolts level i.e., systems of measurement, units of measurement and so on, but what I would call a social history of the uses of measurement. This is not a negative judgement; some parts of the book are excellent exactly because it is about the use and abuse of methods of measurement rather than the systems of measurement themselves.

Although roughly chronological, the book is not a systematic treatment of the use of measurement from the first group of hunter gatherers, who tried to work out an equitable method of dividing the spoils down to the recent redefinition of the kilogram in the metric system. The latter being apparently the episode that stimulated Vincent into writing his book. Such a volume would have to be encyclopaedic in scope, but is rather an episodic examination of various passages in the history of mensuration. 

The first episode or chapter takes a rather sweeping look at what the author sees as the origins of measurement in the early civilisations of Egypt and Babylon. Whilst OK in and of itself, what about other cultures, civilisations, such as China or India just to mention the most obvious. This emphasises something that was already clear from the introduction this is the usual predominantly Eurocentric take on history. 

The second chapter moves into the realm of politics and the role that measurement has always played in social order, with examples from all over the historical landscape. Measurement as a tool of political control. This demonstrates one of the strengths of Vincent’s socio-political approach. Particularly, his detailed analysis of how farmers, millers, and tax collectors all used different tricks to their advantage when measuring grain and the regulation that as a result were introduced is fascinating.

Vincent is, however, a journalist and not a historian and is working from secondary sources and in the introduction, we get the first of a series of really bad takes on the history of science that show Vincent relying on myths and clichés rather than doing proper research. He delivers up the following mess:

Consider, for example, the unlikely patron saint of patient measurement that is the sixteenth-century Danish nobleman Tycho Brahe. By most accounts Brahe was an eccentric, possessed of a huge fortune (his uncle Jørgen Brahe was one of the wealthiest men in the country), a metal nose (he lost the original in a duel), and a pet elk (which allegedly died after drinking too much beer and falling down the stairs of one of his castles). After witnessing the appearance of a new star in the night sky in 1572, one of the handful of supernovae ever seen in our galaxy, Brahe devoted himself to astronomy.

Tycho’s astronomical work was financed with his apanage from the Danish Crown, as a member of the aristocratical oligarchy that ruled Denmark. His uncle Jørgen, Vice-Admiral of the Danish navy, was not wealthier than Tycho’s father or his independently wealthy mother. Tycho had been actively interested in astronomy since 1560 and a serious astronomer since 1563, not first after observing the 1572 supernova.

After describing Tycho’s observational activities, Vincent writes:

It was the data collected here that would allow Brahe’s apprentice, the visionary German astronomer Johannes Kepler, to derive the first mathematical laws of planetary motion which correctly described the elliptical orbits of the planets…

I don’t know why people can’t get Kepler’s status in Prague right. He was not Tycho’s apprentice. He was thirty years old, a university graduate, who had studied under Michael Mästlin one of the leading astronomers in Europe. He was the author of a complex book on mathematical astronomy, which is why Tycho wanted to employ him. He was Tycho’s colleague, who succeeded him in his office as Imperial Mathematicus. 

It might seem that I’m nit picking but if Vincent can’t get simple history of science facts right that he could look up on Wikipedia, then why should the reader place any faith in the rest of what he writes?

The third chapter launches its way into the so-called scientific revolution under the title, The Proper Subject of Measurement. Here Vincent selectively presents the Middle Ages in the worst possible anti-science light, although he does give a nod to the Oxford Calculatores but of course criticises them for being purely theoretical and not experimental. In Vincent’s version they have no predecessors, Philoponus or the Arabic scholars, and no successors, the Paris physicists. He then moves into the Renaissance in a section titled Measuring art, music, and time. First, we get a brief section on the introduction of linear perspective. Here Vincent, first, quoting Alberti, tells us:

I set this up between the eye and the object to be represented, so that the visual pyramid passes through the loose weave of the veil.

The ‘visual pyramid’ described by Alberti refers to medieval theories of optics. Prior to the thirteenth century, Western thinkers believed that vision worked via ‘extramission,’ with the eye emitting rays that interacted with the world like a ‘visual finger reaching out to palpated things’ (a mechanism captured by the Shakespearean imperative to ‘see feelingly’). Thanks largely to the work of the eleventh-century Arabic scholar Ibn al-Haytham, known in the West as Alhacen, this was succeeded by an ‘intromisionist’ explanation, which reverses the causality so that it is the eye that receives impressions from reality. It’s believed that these theories informed the work of artists like Alberti, encouraging the geometrical techniques of the perspective grids and creating a new incentive to divide the world into spatially abstract units.

Here, once again, we have Vincent perpetuating myths because he hasn’t done his homework. The visual pyramid is, of course, from Euclid and like the work of the other Greek promoters of geometrical optics was indeed based on an extramission theory of vision. As I have pointed out on numerous occasions the Greeks actually had both extramission and intromission theories of vision, as well as mixed models. Al-Haytham’s great achievement was not the introduction of an intromission theory, but was in showing that an intromission theory was compatible with the geometrical optics, inclusive visual pyramid, of Euclid et al. The geometrical optics of Alberti and other perspective theorists is pure Euclidian and does not reference al-Haytham. In fact, Alberti explicitly states that it is irrelevant whether the user of his system of linear perspective believes in an extramission or an intromission theory of vision. 

Linear perspective is followed by a two page romp through the medieval invention of musical notation before turning to the invention of the mechanical clock. Here, Vincent makes the standard error of over emphasising the influence of the mechanical clock in the early centuries after its invention and introduction. 

Without mentioning Thomas Kuhn, we now get a Kuhnian explanation of the so-called astronomical revolution, which is wonderfully or should that be horrifyingly anachronistic:

This model [the Aristotelian geocentric one] sustained its authority for centuries, but close observation of the night skies using increasingly accurate telescopes [my emphasis] revealed discrepancies. These were changes that belied its immutable status and movements that didn’t fit the predictions of a simple geocentric universe. A lot of work was done to make the older models account for such eccentricities, but as they accrued mathematical like sticky notes, [apparently sticky notes are the 21st century version of Kuhnian ‘circles upon circles’] doubts about their veracity became unavoidable. 

Where to begin with what can only be described as a clusterfuck. The attempts to reform the Aristotelian-Ptolemaic geocentric model began at the latest with the first Viennese School of Mathematics in the middle of the fifteenth century, about one hundred and fifty years before the invention of the telescope. Those reform attempts began not because of any planetary problems with the model but because the data that it delivered was inaccurate. Major contributions to the development of a heliocentric model such as the work of Copernicus and Tycho Brahe, as well as Kepler’s first two laws of planetary motion also all predate the invention of the telescope. Kepler’s third law is also derived from pre-telescope data. The implication that the geocentric model collapsed under the weight of ad hoc explanation (the sticky notes) was Kuhn’s explanation for his infamous paradigm change and is quite simply wrong. I wrote 52 blog posts explaining what really happened, I’m not going to repeat myself here.

We now get the usual Galileo hagiography for example Vincent tells us: 

It was Galileo who truly mathematised motion following the early attempts of the Oxford Calculators, using practical experiments to demonstrate flaws in Aristotelian wisdom.

Vincent ignores the fact that Aristotle’s concepts of motion had been thrown overboard long before and completely ignores the work of sixteenth century mathematicians, such as Tartaglia and Benedetti. 

He then writes:

In one famous experiment he dropped cannonballs and musket balls from the Leaning Tower of Pisa (an exercise that likely never took place in the way Galileo claims [my emphasis]) and showed that, contra to Aristotle, objects accelerate at a uniform rate, not proportionally to their mass.

Galileo never claimed to have dropped anything from the Leaning Tower, somebody else said that he had and if it ‘never took place’, why fucking mention it?

Now the telescope:

From 1609, Galileo’s work moved to a new plane itself. Using home-made telescopes he’d constructed solely by reading descriptions of the device…

The myth, created by himself, that Galileo had never seen a telescope before he constructed one has been effectively debunked by Mario Biagioli. This is followed by the usually one man circus claims about the telescopic discoveries, completely ignoring the other early telescope observers. Copernicus and Kepler now each get a couple of lines before we head off to Isaac Newton. Vincent tells us that Newton devised the three laws of motion and the universal law of gravitation. He didn’t he took them from others and combined them to create his synthesis.

The fourth chapter of the book is concerned with the invention of the thermometer and the problems of creating accurate temperature scales. This chapter is OK, however, Vincent is a journalist and not a historian and relies on secondary sources written by historians. There is nothing wrong with this, it’s how I write my blog posts. In this chapter his source is the excellent work of Hasok Chang, which I’ve read myself and if any reader in really interested in this topic, I recommend that they read Chang rather than Chang filtered by Vincent. Once again, we have some very sloppy pieces of history of science, Vincent writes: 

Writing in 1693, the English astronomer Edmond Halley, discoverer of the eponymous comet…”

Just for the record, Halley was much more than just an astronomer, he could for example have been featured along with Graunt in chapter seven, see below. It is wrong to credit Halley with the discovery of Comet Halley. The discoverer is the first person to observe a comet and record that observation. Comet Halley had been observed and recorded many times throughout history and Halley’s achievement was to recognise that those observations were all of one and the same comet.

 A few pages further on Vincent writes: 

Unlike caloric, phlogiston had mass, but Lavoisier disproved this theory, in part by showing how some substances gain weight when burned. (This would eventually lead to the discovery of oxygen as the key element in combustion.) [my emphasis]

I can hear both Carl Scheele and Joseph Priestley turning in their graves. Both of them discovered oxygen, independently of each other; Scheele discovered it first bur Priestly published first, and both were very much aware of its role in combustion and all of this well before Lavoisier became involved. 

Chapter five is dedicated to the introduction of the metric system in France correctly giving more attention to the political aspects than the numerical ones. Once again, an excellent chapter.

Chapter six which deals primarily with land surveying had a grandiose title, A Grid Laid Across the World, but is in fact largely limited to the US. Having said that it is a very good and informative chapter, which explains how it came about that the majority of US towns and properties are laid out of a unified rectangular grid system. Most importantly it explains how the land grant systems with its mathematical surveying was utilised to deprive the indigenous population of their traditional territories. The chapter closes with a brief more general look at how mathematical surveying and mapping played a significant role in imperialist expansion, with a very trenchant quote from map historian, Matthew Edney, “The empire exists because it can be mapped; the meaning of empire is inscribed into each map.”

Unfortunately, this chapter also contains some more sloppy history of science, Vincent tells us:

In such a world, measurement of the land was of the utmost importance. As a result, sixteenth-century England gave rise to one of the most widely used measuring tools in the world: the surveyor’s chain, or Gunter’s chain, named after its inventor the seventeenth-century English priest and mathematician Edmund Gunter. 

Sixteenth or seventeenth century? Which copy editor missed that one? It’s actually a bit of a problem because Gunter’s life starts in the one century and ends in the other, 1581–1626. However, we can safely say that he produced his chain in the seventeenth century. Vincent makes the classic error of attributing the invention of the surveyors’ chain to Gunter, to quote myself from my blog post on Renaissance surveying:

In English the surveyor’s chain is usually referred to as Gunter’s chain after the English practical mathematician Edmund Gunter (1581–1626) and he is also often referred to erroneously as the inventor of the surveyor’s chain but there are references to the use of the surveyor’s chain in 1579, before Gunter was born. 

Even worse he writes:

Political theorist Hannah Arendt described the work of surveying and mapping that began with the colonisation of America as one of three great events that ‘stand at the threshold of the modern age and determine its character’ (the other two being the Reformation of the Catholic Church and the cosmological revolution begun by Galileo) [my emphasis]

I don’t know whether to attribute this arrant nonsense to Arendt or to Vincent. Whether he is quoting her or made this up himself he should know better, it’s complete bullshit. Whatever Galileo contributed to the ‘cosmological revolution,’ and it’s much, much less than is often claimed, he did not in anyway begin it. Never heard of Copernicus, Tycho, Kepler, Mr Vincent? Oh yes, you talk about them in chapter three!

Chapter seven turns to population statistics starting with the Royal Society and John Graunt’s Natural and Political Observations Made Upon the Bills of Mortality. Having dealt quite extensively with Graunt, with a nod to William Petty, but completely ignoring the work of Caspar Neumann and Edmond Halley, Vincent now gives a brief account of the origins of the new statistics. Strangely attributing this entirely to the astronomers, completely ignoring the work on probability in games of chance by Cardano, Fermat, Pascal, and Christian Huygens. He briefly mentions the work of Abraham de Moivre but ignores the equally important, if not more important work of Jacob Bernoulli. He now gives an extensive analysis of Quetelet’s application of statistics to the social sciences. Quetelet, being an astronomer, is Vincent’s reason d’être for claiming that it was astronomers, who initial developed statistics and not the gamblers. Quetelet’s the man who gave us the ubiquitous body mass index. The chapter then closes with a good section on the abuses of statistics in the social sciences, first in Galton’s eugenics and secondly in the misuse of IQ tests by Henry Goddard. All in all, one of the good essays in the book

Continuing the somewhat erratic course from theme to theme, the eighth chapter addresses what Vincent calls The Battle of the Standards: Metric vs Imperial and metrology’s culture war. A very thin chapter, more of a sketch that an in-depth analysis, which gives as much space to the post Brexit anti-metric loonies, as to the major debates of the nineteenth century. This is mainly so that Vincent can tell the tale of his excursion with said loonies to deface street signs as an act of rebellion. 

In the ninth chapter, Vincent turns his attention to replacement of arbitrary definitions of units of measurement with definitions based on constants of nature, with an emphasis on the recent new definition of the kilogram. At various point in the book, Vincent steps out from his role of playing historian and presents himself in the first person as an investigative journalist, a device that I personally found irritating. In this chapter this is most pronounced. He opens with, “On a damp but cheerful Friday in November 2018, I travelled to the outskirts of Paris to witness the overthrow of a king.” He carries on in the same overblown style finally revealing that he, as a journalist was attending the conference officially launching the redefining of the kilogram, going on to explain in equally overblown terms how the kilogram was originally defined. The purple prose continues with the introduction of another attendee, his acquaintance, the German physicist, Stephan Schlamminger:

Schlamminger is something of a genius loci of metrology: an animating spirit full of cheer and knowledge, as comfortable in the weights and measures as a fire in a heath. He is also a key player in the American team that helped create the kilogram’s new definition. I’d spoken to him before, but always delighted in his enthusiasm and generosity. ‘James, James, James,’ he says in a rapid-fire German accent as he beckoned me to join his group. ‘Welcome to the party.’

We then get a long, overblown speech by Schlamminger about the history of the definitions in the metric system ending with an explanation, as to why the kilogram must be redefined.

This is followed by a long discourse over Charles Sanders Peirce and his attempts to define the metre using the speed of light, which failed. Vincent claims that Peirce was the first to attempt to attempt to define units of measurement using constants of nature, a claim that I find dubious, but it might be right. This leads on to Michelson and Morley defining the metre using the wavelength of sodium light, a definition that in modified form is still used today. The chapter closes with a long, very technical, and rather opaque explanation of the new definition of the kilogram based on Planck’s constant, h

The final chapter of Vincent’s book is a sociological or anthropological mixed basket of wares under the title The Managed Life: Measurements place in modern society in our understanding of ourselves, which is far too short to in anyway fulfil its grandiose title.

The book closes with an epilogue that left me simply baffled. He tells a personal story about how he came to listen to Beethoven’s Ninth Symphony only when he had a personal success in his life and through this came to ruin his enjoyment of the piece. Despite his explanation I fail to see what the fuck this has to do with measurement.

The book has a rather small, random collection of colour prints, related to various bits of the text, in the middle. There are extensive endnotes relating bits of the text to there bibliographical sources, but no separate bibliography, and an extensive index.

I came away feeling that there is a good book contained in Vincent’s tome, struggling to get out. However, there is somehow too much in the way for it to emerge. Some of the individual essays are excellent and I particularly liked his strong emphasis on some of the negative results of applying systems of measurement. People reading this review might think that I, as a historian of science, have placed too much emphasis on his truly shoddy treatment of that discipline; ‘the cosmological revolution begun by Galileo,’ I ask you? However, as I have already stated if we can’t trust his research in this area, how much can we trust the rest of his work?

[1] Wisdom of Solomon 11:20

[2] James Vincent, Beyond MeasureThe Hidden History of Measurement, Faber & Faber, London, 2022


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


Due to the impact of Isaac Newton and the mathematicians grouped around him, people often have a false impression of the role that England played in the history of the mathematical sciences during the Early Modern Period. As I have noted in the past, during the late medieval period and on down into the seventeenth century, England in fact lagged seriously behind continental Europe in the development of the mathematical sciences both on an institutional level, principally universities, and in terms of individual mathematical practitioners outside of the universities. Leading mathematical practitioners, working in England in the early sixteenth century, such as Thomas Gemini (1510–1562) and Nicolas Kratzer (1486/7–1550) were in fact immigrants, from the Netherlands and Germany respectively.

In the second half of the century the demand for mathematical practitioners in the fields of astrology, astronomy, navigation, cartography, surveying, and matters military was continually growing and England began to produce some home grown talent and take the mathematical disciplines more seriously, although the two universities, Oxford and Cambridge still remained aloof relying on enthusiastic informal teachers, such as Thomas Allen (1542–1632) rather than instituting proper chairs for the study and teaching of mathematics.

Outside of the universities ardent fans of the mathematical disciplines began to establish the so-called English school of mathematics, writing books in English, giving tuition, creating instruments, and carrying out mathematical tasks. Leading this group were the Welsh man, Robert Recorde (c. 1512–1558), who I shall return to in a later post, John Dee (1527–c. 1608), who I have dealt with in several post in the past, one of which outlines the English School, other important early members being, Dee’s friend Leonard Digges, and his son Thomas Digges (c. 1446–1595), who both deserve posts of their own, and Thomas Hood (1556–1620) the first officially appointed lecturer for mathematics in England.  I shall return to give all these worthy gentlemen, and others, the attention they deserve but today I shall outline the life and mathematical career of John Blagrave (d. 1611) a member of the landed gentry, who gained a strong reputation as a mathematical practitioner and in particular as a designer of mathematical instruments, the antiquary Anthony à Wood (1632–1695), author of Athenae Oxonienses. An Exact History of All the Writers and Bishops, who Have Had Their Education in the … University of Oxford from the Year 1500 to the End of the Year 1690, described him as “the flower of mathematicians of his age.”

John Blagrave was the second son of another John Blagrave of Bullmarsh, a district of Reading, and his wife Anne, the daughter of Sir Anthony Hungerford of Down-Ampney, an English soldier, sheriff, and courtier during the reign of Henry VIII, John junior was born into wealth in the town of Reading in Berkshire probably sometime in the 1560s. He was educated at Reading School, an old established grammar school, before going up to St John’s College Oxford, where he apparently acquired his love of mathematics. This raises the question as to whether he was another student, who benefitted from the tutoring skills of Thomas Allen (1542–1632). He left the university without graduating, not unusually for the sons of aristocrats and the gentry. He settled down in Southcot Lodge in Reading, an estate that he had inherited from his father and devoted himself to his mathematical studies and the design of mathematical instruments. He also worked as a surveyor and was amongst the first to draw estate maps to scale.

Harpsden a small parish near Henley-on-Thames Survey by John Blagrave 1589 Source

There are five known surviving works by Blagrave and one map, as opposed to a survey, of which the earliest his, The mathematical ievvel, from1585, which lends its name to the title of this post, is the most famous. The full title of this work is really quite extraordinary:


Shewing the making, and most excellent vse of a singuler Instrument So called: in that it performeth with wonderfull dexteritie, whatsoever is to be done, either by Quadrant, Ship, Circle, Cylinder, Ring, Dyall, Horoscope, Astrolabe, Sphere, Globe, or any such like heretofore deuised: yea or by most Tables commonly extant: and that generally to all places from Pole to Pole. 

The vse of which Ievvel, is so aboundant and ample, that it leadeth any man practising thereon, the direct pathway (from the first steppe to the last) through the whole Artes of Astronomy, Cosmography, Geography, Topography, Nauigation, Longitudes of Regions, Dyalling, Sphericall triangles, Setting figures, and briefely of whatsoeuer concerneth the Globe or Sphere: with great and incredible speede, plainenesse, facillitie, and pleasure:

The most part newly founde out by the Author, Compiled and published for the furtherance, aswell of Gentlemen and others desirous or Speculariue knowledge, and priuate practise: as also for the furnishing of such worthy mindes, Nauigators,and traueylers,that pretend long voyages or new discoueries: By John Blagave of Reading Gentleman and well willer to the Mathematickes; Who hath cut all the prints or pictures of the whole worke with his owne hands. 1585•

Dig the spelling!
Title Page Source Note the title page illustration is an  armillary sphere and not the Mathematical Jewel

Blagrave’s Mathematical Jewel is in fact a universal astrolabe, and by no means the first but probably the most extensively described. The astrolabe is indeed a multifunctional instrument, al-Sufi (903–983) describes over a thousand different uses for it, and Chaucer (c. 1340s–1400) in what is considered to be the first English language description of the astrolabe and its function, a pamphlet written for a child, describes at least forty different functions. However, the normal astrolabe has one drawback, the flat plates, called tympans of climata, that sit in the mater and are engraved with the stereographic projection of a portion of the celestial sphere are limited in their use to a fairly narrow band of latitude, meaning that if one wishes to use it at a different latitude you need a different climata. Most astrolabes have a set of plates each engraved on both side for a different band of latitude. This problem led to the invention of the universal astrolabe.

Full-page figure of the rete of Blagrave’s Jewel (Peterborough A.8.13) For more illustration from The Mathematical Jewel go here

The earliest known universal astrolabes are attributed to Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī al-Tujibi (1029-1100), known simply as al-Zarqālī and in Latin as Arzachel, an Arabic astronomer, astrologer, and instrument maker from Al-Andalus, and another contemporary Arabic astronomer, instrument maker from Al-Andalus, Alī ibn Khalaf: Abū al‐Ḥasan ibn Aḥmar al‐Ṣaydalānī or simply Alī ibn Khalaf, about whom very little is known. In the Biographical Encyclopedia of Astronomers (Springer Reference, 2007, pp. 34-35) Roser Puig has this to say about the two Andalusian instrument makers: 

ʿAlī ibn Khalaf is the author of a treatise on the use of the lámina universal (universal plate) preserved only in a Spanish translation included in the Libros del Saber de Astronomía (III, 11–132), compiled by the Spanish King Alfonso X. To our knowledge, the Arabic original is lost. ʿAlī ibn Khalaf is also credited with the construction of a universal instrument called al‐asṭurlāb al‐maʾmūnī in the year 1071, dedicated to al‐Maʾmūn, ruler of Toledo. 

The universal plate and the ṣafīḥa (the plate) of Zarqalī (devised in 1048) are the first “universal instruments” (i.e., for all latitudes) developed in Andalus. Both are based on the stereographic meridian projection of each hemisphere, superimposing the projection of a half of the celestial sphere from the vernal point (and turning it) on to the projection of the other half from the autumnal point. However, their specific characteristics make them different instruments.

Al-Zarqālī’s universal astrolabe was known as the Azafea in Arabic and as the Saphaea in Europe.

A copy of al-Zarqālī’s astrolabe Source: Wikimedia Commons

Much closer to Blagrave’s time, Gemma Frisius (1508–1555) wrote about a universal astrolabe, published as the Medici ac Mathematici de astrolabio catholico liber quo latissime patientis instrumenti multiplex usus explicatur, in 1556. Better known than Frisius’ universal instrument was that of his one-time Spanish, student Juan de Rojas y Samiento (fl. 1540-1550) published in his Commentariorum in Astrolabium libri sex in 1551.


Although he never really left his home town of Reading and his work was in English, Blagrave, like the other members of the English School of Mathematics, was well aware of the developments in continental Europe and he quotes the work of leading European mathematical practitioners in his Mathematical Jewel, such as the Tübingen professor of mathematics, Johannes Stöffler (1452–1531), who wrote a highly influential volume on the construction of astrolabes, his Elucidatio fabricae ususque astrolabii originally published in 1513, which went through 16 editions up to 1620

or the works of Gemma Frisius, who was possibly the most influential mathematical practitioner of the sixteenth century. Blagrave’s Mathematical Jewel was based on Gemma Frisius astrolabio catholico.

Blagrave’s Mathematical Jewel was obviously popular because Joseph Moxon (1627–1691), England first specialist mathematical publisher, cartographer, instrument, and globe maker republished it under the title:

The catholique planisphaer which Mr. Blagrave calleth the mathematical jewel briefly and plainly discribed in five books : the first shewing the making of the instrument, the rest shewing the manifold vse of it, 1. for representing several projections of the sphere, 2. for resolving all problemes of the sphere, astronomical, astrological, and geographical, 4. for making all sorts of dials both without doors and within upon any walls, cielings, or floores, be they never so irregular, where-so-ever the direct or reflected beams of the sun may come : all which are to be done by this instrument with wonderous ease and delight : a treatise very usefull for marriners and for all ingenious men who love the arts mathematical / by John Palmer … ; hereunto is added a brief description of the cros-staf and a catalogue of eclipses observed by the same I.P.

Engraved frontispiece to John Palmer (ed.), ‘The Catholique Planispaer, which Mr Blagrave calleth the Mathematical Jewel’ (London, Joseph Moxon, 1658); woman, wearing necklace, bracelet, jewels in her hair, and a veil, and seated at a table, on which are a design of a mathematical sphere, a compass, and an open book; top left, portrait of John Blagrave, wearing a ruff; top right, portrait of John Palmer; top centre, an angel with trumpets.
Engraving David Loggan Source: British Museum

John Palmer (1612-1679), who was apparently rector of Ecton and archdeacon of Northampton, is variously described as the author or the editor of the volume, which was first published in 1658 and went through sixteen editions up to 1973.

Following The Mathematical Jewel, Blagrave published four further books on scientific instruments that we know of: 

Baculum Familliare, Catholicon sive Generale. A Booke of the making and use of a Staffe, newly invented by the Author, called the Familiar Staffe (London, 1590)

Astrolabium uranicum generale, a necessary and pleasaunt solace and recreation for navigators … compyled by John Blagrave (London, 1596)

An apollogie confirmation explanation and addition to the Vranicall astrolabe (London, 1597)

None of these survive in large numbers.

Blagrave also manufactured sundials and his fourth instrument book is about this: 

The art of dyalling in two parts (London, 1609)


Here there are considerably more surviving copies and even a modern reprint by Theatrum Orbis Terrarum Ltd., Da Capo Press, Amsterdam, New York, 1968.

People who don’t think about it tend to regard books on dialling, that is the mathematics of the construction and installation of sundials, as somehow odd. However, in this day and age, when almost everybody walks around with a mobile phone in their pocket with a highly accurate digital clock, we tend to forget that, for most of human history, time was not so instantly accessible. In the Early Modern period, mechanical clocks were few and far between and mostly unreliable. For time, people relied on sundials, which were common and widespread. From the invention of printing with movable type around 1450 up to about 1700, books on dialling constituted the largest genre of mathematical books printed and published. Designing and constructing sundials was a central part of the profession of mathematical practitioners. 

As well as the books there is one extant map:

Noua orbis terrarum descriptio opti[c]e proiecta secundu[m]q[ue] peritissimos Anglie geographos multis ni [sic] locis castigatissima et preceteris ipsiq[ue] globo nauigationi faciliter applcanda [sic] per Ioannem Blagrauum gen[er]osum Readingensem mathesibus beneuolentem Beniamin Wright Anglus Londinensis cµlator anno Domini 1596 

This is described as:

Two engraved maps, the first terrestrial, the second celestial (“Astrolabium uranicum generale …”). Evidently intended to illustrate Blagrave’s book “Astrolabium uranicum generale” but are not found in any copy of the latter.
The original is in the Bodleian Library.

When he died in 1611, Blagrave was buried in the St Laurence Church in Reading with a suitably mathematical monument. 

Blagrave is depicted surrounded by allegorical mathematical figures, with five women each holding the five platonic solids and Blagrave (in the center) depicted holding a globe and a quadrant.
The monument was the work of the sculptor Gerard Christmas (1576–1634), who later in life was appointed carver to the navy. It is not known who produced the drawing of the monument. 
Modern reconstruction of the armillary sphere from the cover of The Mathematical Jewel created by David Harber a descendent of John Blagrave

Blagrave was a minor, but not insignificant, participant in the mathematical community in England in the late sixteenth century. His work displays the typical Renaissance active interest in the practical mathematical disciplines, astronomy, navigation, surveying, and dialling. He seems to have enjoyed a good reputation and his Mathematical Jewel appears to have found a wide readership.  


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

The Wizard Earl’s mathematici 

In my recent post on the Oxford mathematician and astrologer Thomas Allen, I mentioned his association with Henry Percy, 9th Earl of Northumberland, who because of his strong interest in the sciences was known as the Wizard Earl.

HENRY PERCY, 9TH EARL OF NORTHUMBERLAND (1564-1632) by Sir Anthony Van Dyck (1599-1641). The ‘Wizard Earl’ was painted posthumously as a philosopher, hung in Square Room at Petworth. This is NT owned. via Wikimedia Commons

As already explained there Percy actively supported four mathematici, or to use the English term mathematical practitioners, Thomas Harriot (c. 1560–1621), Robert Hues (1553–1632), Walter Warner (1563–1643), and Nathaniel Torporley (1564–1632). Today, I’m going to take a closer look at them.

Thomas Harriot is, of course, the most well-known of the four; I have already written a post about him in the past, so I will only brief account of the salient point here.

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

He graduatied from Oxford in 1580 and entered the service of Sir Walter Raleigh (1552–1618) in 1583. At Raleigh’s instigation he set up a school to teach Raleigh’s marine captains the newest methods of navigation and cartography, writing a manual on mathematical navigation, which contained the correct mathematical method for the construction of the Mercator projection. This manual was never published but we can assume he used it in his teaching. He was also directly involved in Raleigh’s voyages to establish the colony of Roanoke Island.

Sir Walter Ralegh in 1588 artist unknown. Source: Wikimedia Commons

In 1590, he left Raleigh’s service and became a pensioner of Henry Percy, with a very generous pension, the title to some land in the North of England, and a house on Percy’s estate, Syon House, in Middlesex.[1] Here, Harriot lived out his years as a research scientist with no obligations.

Syon House Attributed to Robert Griffier

After Harriot, the most significant of the Wizard Earl’s mathematici was Robert Hues. Like Harriot, Hues attended St Mary’s Hall in Oxford, graduating a couple of years ahead of him in 1578. Being interested in geography and mathematics, he was one of those who studied navigation under Harriot in the school set up by Raleigh, having been introduced to Raleigh by Richard Hakluyt (1553–1616), another student of Thomas Allen and a big promoter of English colonisation of North America.  

Hakluyt depicted in stained glass in the west window of the south transept of Bristol Cathedral – Charles Eamer Kempe, c. 1905. Source: Wikimedia Commons

Hues went on to become an experienced mariner. During a trip to Newfoundland, he came to doubt the published values for magnetic declination, the difference between magnetic north and true north, which varies from place to place.

In 1586, he joined with Thomas Cavendish (1560–1592), a privateer and another graduate of the Harriot school of navigation, who set out to raid Spanish shipping and undertake a circumnavigation of the globe, leaving Plymouth with three ships on 21 July. After the usual collection of adventures, they returned to Plymouth with just one ship on 9 September 1588, as the third ever ship to complete the circumnavigation after Magellan and Drake. Like Drake, Cavendish was knighted by Queen Elizabeth for his endeavours.

Thomas Cavendish An engraving from Henry Holland’s Herōologia Anglica (1620). Animum fortuna sequatur is Latin for “May fortune follow courage.” Source: Wikimedia Commons

Hues undertook astronomical observations throughout the journey and determined the latitudes of the places they visited. In 1589, he served with the mathematicus Edward Wright (1561–1615), who like Harriot worked out the correct mathematical method for the construction of the Mercator projection, but unlike Harriot published it in his Certaine Errors in Navigation in 1599.

Source: Wikimedia Commons

In August 1591, he set out once again with Cavendish on another attempted circumnavigation, also accompanied by the navigator John Davis (c. 1550–1605), another associate of Raleigh’s, known for his attempts to discover the North-West passage and his discovery of the Falkland Islands.

Miniature engraved portrait of navigator John Davis (c. 1550-1605), detail from the title page of Samuel Purchas’s Hakluytus Posthumus or Purchas his Pilgrimes (1624). Source: Wikimedia Commons

Cavendish died on route in 1592 and Hues returned to England with Davis in 1683. On this voyage Hues continued his astronomical observations in the South Atlantic and made determinations of compass declinations at various latitudes and the equator. 

Back in England, Hues published the results of his astronomical and navigational research in his Tractatus de globis et eorum usu (Treatise on Globes and Their Use, 1594), which was dedicated to Raleigh.

The book was a guide to the use of the terrestrial and celestial globes that Emery Molyneux (died 1598) had published in 1592 or 1593.

Molyneux CEltial Globe Middle Temple Library
A terrestrial globe by Emery Molyneux (d.1598-1599) is dated 1592 and is the earliest such English globe in existence. It is weighted with sand and made from layers of paper with a surface coat of plaster engraved with elaborate cartouches, fanciful sea-monsters and other nautical decoration by the Fleming Jodocus Hondius (1563-1611). There is a wooden horizon circle and brass meridian rings.

Molyneux belong to the same circle of mariners and mathematici, counting Hues, Wright, Cavendish, Davis, Raleigh, and Francis Drake (c. 1540–1596) amongst his acquaintances. In fact, he took part in Drake’s circumnavigation 1577–1580. These were the first globes made in England apparently at the suggestion of John Davis to his patron the wealthy London merchant William Sanderson (?1548–1638), who financed the construction of Molyneux’s globes to the tune of £1,000. Sanderson had sponsored Davis’ voyages and for a time was Raleigh’s financial manager. He named his first three sons Raleigh, Cavendish, and Drake.

Molyneux’s terrestrial globe was his own work incorporating information from his mariner friends and with the assistance of Edward Wright in plotting the coast lines. The circumnavigations of Drake and Cavendish were marked on the globe in red and blue line respectively. His celestial globe was a copy of the 1571 globe of Gerard Mercator (1512–1594), which itself was based on the 1537 globe of Gemma Frisius (1508–1555), on which Mercator had served his apprenticeship as globe maker. Molyneux’s globes were engraved by Jodocus Hondius (1563–1612), who lived in London between 1584 and 1593, and who would upon his return to the Netherlands would found one of the two biggest cartographical publishing houses of the seventeenth century.

Hues’ Tractatus de globis et eorum usu was one of four publications on the use of the globes. Molyneux wrote one himself, The Globes Celestial and Terrestrial Set Forth in Plano, published by Sanderson in 1592, of which none have survived. The London public lecturer on mathematics Thomas Hood published his The Vse of Both the Globes, Celestiall and Terrestriall in 1592, and finally Thomas Blundeville (c. 1522–c. 1606) in his Exercises containing six treatises including Cosmography, Astronomy, Geography and Navigation in 1594.

Hues’ Tractatus de globis has five sections the first of which deals with a basic description of and use of Molyneux’s globes. The second is concerned with matters celestial, plants, stars, and constellations. The third describes the lands, and seas displayed on the terrestrial globe, the circumference of the earth and degrees of a great circle. Part four contains the meat of the book and explains how mariners can use the globes to determine the sun’s position, latitude, course and distance, amplitudes and azimuths, and time and declination. The final section is a treatise, inspired by Harriot’s work on rhumb lines, on the use of the nautical triangle for dead reckoning. Difference of latitude and departure (or longitude) are two legs of a right triangle, the distance travelled is the hypotenuse, and the angle between difference of latitude and distance is the course. If any two elements are known, the other two can be determined by plotting or calculation using trigonometry.

The book was a success going through numerous editions in various languages. The original in Latin in 1593, Dutch in 1597, an enlarged and corrected Latin edition in 1611, Dutch again in 1613, enlarged once again in Latin in 1617, French in 1618, another Dutch edition in 1622, Latin again in 1627, English in 1638, Latin in 1659, another English edition also in 1659, and finally the third enlarged Latin edition reprinted in 1663. There were others.

The title page of Robert Hues (1634) Tractatvs de Globis Coelesti et Terrestri eorvmqve vsv in the collection of the Biblioteca Nacional de Portugal via Wikimedia Commons

Hues continued his acquaintance with Raleigh in the 1590s and was one of the executors of Raleigh’s will. He became a servant of Thomas Grey, 15th Baron Gray de Wilton (died 1614) and when Grey was imprisoned in the Tower of London for his involvement in a Catholic plot against James I & VI in 1604, Hues was granted permission to visit and even to stay with him in the Tower. From 1605 to 1621, Northumberland was also incarcerated in the Tower because of his family’s involvement in the Gunpowder Plot. Following Grey’s death Hues transferred his Tower visits to Northumberland, who paid him a yearly pension of £40 until his death in 1632.

He withdrew to Oxford University and tutored Henry Percy’s oldest son Algernon, the future 10th Earl of Northumberland, in mathematics when he matriculated at Christ’s Church in 1617.

Algernon Percy, 10th Earl of Northumberland, as Lord High Admiral of England, by Anthony van Dyck. Source: Wikimedia Commons

In 1622-23 he would also tutor the younger son Henry.

Oil painting on canvas, Henry Percy, Baron Percy of Alnwick (1605-1659) by Anthony Van Dyck Source: Wikimedia Commons

During this period, he probably visited both Petworth and Syon, Northumberland’s southern estates. He in known to have had discussion with Walter Warner on reflection. He remained in Oxford discussing mathematics with like minded fellows until his death.

Compared to the nautical adventures of Harriot and Hues, both Warner and Torporley led quiet lives. Walter Warner was born in Leicestershire and educated at Merton College Oxford graduating BA in 1579, the year between Hues and Harriot. According to John Aubrey in his Brief Lives, Warner was born with only one hand. It is almost certain that Hues, Warner, and Harriot met each other attending the mathematics lectures of Thomas Allen at Oxford. Originally a protégé of Robert Dudley, 1st Earl of Leicester, (1532–1588), he entered Northumberland’s household as a gentleman servitor in 1590 and became a pensioner in 1617. Although a servant, Warner dined with the family and was treated as a companion by the Earl. In Syon house, he was responsible for purchasing the Earl’s books, Northumberland had one of the largest libraries in England, and scientific instruments. He accompanied the Earl on his military mission to the Netherlands in 1600-01, acting as his confidential courier.       

Like Harriot, Warner was a true polymath, researching and writing on a very wide range of topics–logic, psychology, animal locomotion, atomism, time and space, the nature of heat and light, bullion and exchange, hydrostatics, chemistry, and the circulation of the blood, which he claimed to have discovered before William Harvey. However, like Harriot he published almost nothing, although, like Harriot, he was well-known in scholarly circles. Some of his work on optics was published posthumously by Marin Mersenne (1588–1648) in his Universæ geometriæ (1646).

Source: Google Books

It seems that following Harriot’s death Warner left Syon house, living in Charing Cross and at Cranbourne Lodge in Windsor the home of Sir Thomas Aylesbury, 1st Baronet (!576–1657), who had also been a student of Thomas Allen, and who had served both as Surveyor of the Navy and Master of the Mint. Aylesbury became Warner’s patron.

This painting by William Dobson probably represents Sir Thomas Aylesbury, 1st Baronet. 
Source: Wikimedia Commons

Aylesbury had inherited Harriot’s papers and encouraged Warner in the work of editing them for publication (of which more later), together with the young mathematician John Pell (1611–1685), asking Northumberland for financial assistance in the endeavour.

Northumberland died in 1632 and Algernon Percy the 10th Earl discontinued Warner’s pension. In 1635, Warner tried to win the patronage of Sir Charles Cavendish and his brother William Cavendish, enthusiastic supporters of the new scientific developments, in particular Keplerian astronomy. Charles Cavendish’s wife was the notorious female philosopher, Margaret Cavendish. Warner sent Cavendish a tract on the construction of telescopes and lenses for which he was rewarded with £20. However, Thomas Hobbes, another member of the Cavendish circle, managed to get Warner expelled from Cavendish’s patronage. Despite Aylesbury’s support Warner died in poverty. 

Nathaniel Torporley was born in Shropshire of unknow parentage and educated at Shrewsbury Grammar Scholl before matriculating at Christ Church Oxford in 1581. He graduated BA in 1584 and then travelled to France where he served as amanuensis to the French mathematician François Viète (1540–1603).

François Viète Source: Wikimedia Commons

He is thought to have supplied Harriot with a copy of Viète’s Isagoge, making Harriot the first English mathematician to have read it.


Torporley returned to Oxford in 1587 or 1588 and graduated MA from Brasenose College in 1591. 

He entered holy orders and was appointed rector of Salwarpe in Worcestershire, a living he retained until 1622. From 1611 he was also rector of Liddington in Wiltshire. His interest in mathematics, astronomy and astrology attracted the attention of Northumberland and he probably received a pension from him but there is only evidence of one payment in 1627. He was investigated in 1605, shortly before the Gunpowder Plot for having cast a nativity of the king. At some point he published a pamphlet, under the name Poulterey, attacking Viète. In 1632, he died at Sion College, on London Wall and in a will written in the year of his death he left all of his books, papers, and scientific instrument to the Sion College library.

Although his papers in the Sion College library contain several unpublished mathematical texts, still extant today, he only published one book his Diclides Coelometricae; seu Valuae Astronomicae universales, omnia artis totius munera Psephophoretica in sat modicis Finibus Duarum Tabularum methodo Nova, generali et facillima continentes, (containing a preface, Directionis accuratae consummata Doctrina, Astrologis hactenus plurimum desiderata and the Tabula praemissilis ad Declinationes et coeli meditations) in London in 1602.


This is a book on how to calculate astrological directions, a method for determining the time of major incidents in the life of a subject including their point of death, which was a very popular astrological method in the Renaissance. This requires spherical trigonometry, and the book is interesting for containing new simplified methods of solving right spherical triangles of any sort, methods that are normally attributed to John Napier (1550–1617) in a later publication. The book is, however, extremely cryptic and obscure, and almost unreadable. Despite this the surviving copies would suggest that it was widely distributed in Europe.

Our three mathematici came together as executors of Harriot’s will. Hues was charged with pricing Harriot’s books and other items for sale to the Bodleian Library. Hues and Torporley were charged with assisting Warner with the publication of Harriot’s mathematical manuscripts, a task that the three of them managed to bungle. In the end they only managed to publish one single book, Harriot’s algebra Artis Analyticae Praxis in 1631 and this text they castrated.


Harriot’s manuscript was the most advanced text on the topic written at the time and included full solutions of algebraic equations including negative and complex solutions. Either Warner et al did not understand Harriot’s work or they got cold feet in the face of his revolutionary new methods, whichever, they removed all of the innovative parts of the book making it basically irrelevant and depriving Harriot of the glory that was due to him.

For myself the main lesson to be learned from taking a closer look at the lives of this group of mathematici is that it shows that those interested in mathematics, astronomy, cartography, and navigation in England the late sixteenth and early seventeenth centuries were intricately linked in a complex network of relationships, which contains hubs one of which was initially Harriot and Raleigh and then later Harriot and Northumberland. 

[1] For those who don’t know, Middlesex was a small English county bordering London, in the South-West corner of Essex, squeezed between Hertfordshire to the north and Surry in the South, which now no longer exists having been largely absorbed into Greater London. 


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

The sixteenth century dispute about higher order algebraic equations and their solution

The Early Modern period is full of disputes between scholars about questions of priority and accusations of the theft of intellectual property. One reason for this is that the modern concepts of copyright and patent rights simply didn’t exist then, however, that is not the topic of this post. One of the most notorious disputes in the sixteenth century concerned Niccolò Fontana Tartaglia’s discovery of the solution to one form of cubic equation and Gerolamo Cardano’s publication of that solution, despite a promise to Tartaglia not to do so, in his book Artis Magnae, Sive de Regulis Algebraicis Liber Unus, commonly known as the Ars Magna in 1545. A version of this story can be found is every general history of mathematics book and there are numerous versions to be found on the Internet. I blogged about it twelve years ago and maths teacher and historian, Dave Richeson wrote about it just last month in Quanta Magazine

Despite all of this, I am going to review a book about the story that I recently acquired and read, Fabio Toscano, The Secret FormulaHow a Mathematical Duel Inflamed Renaissance Italy and Uncovered the Cubic Equation.[1] 

Unlike most of my book reviews this is not a new book, it was originally published in Italian as, La formula segreta, in 2009 and the English translation appeared in 2020. I caught a glimpse of it on the Princeton University Press website at half price in their summer sale and on a whim decided to buy it.[2] I’m glad that I did, as it is an excellent retelling of the story using all of the original documents, which adds a whole new depth to it, not found in the popular versions. 

Toscano’s book, which is comparatively short, has six chapters each of which deals with a distinctive aspect of the sequence of historical events that he is narrating. The opening chapters introduces one of the principal characters in this story Niccolò Fontana, describing his lowly birth, his facial disfigurement delivered by a soldier during the 1512 storm of Brescia, which gave him the stutter by which he was known, Tartaglia. How the autodidactic mathematician became an abaco master, a private teacher of arithmetic, algebra, bookkeeping and elementary geometry.

The second chapter is a brief sketch of history of algebra up to the Renaissance. The elementary nature of ancient Egyptian algebra, the much more advanced nature of Babylonian algebra including the partial general solution of the quadratic equation. Partial, because the Babylonians didn’t acknowledge negative solutions. Here we have one of the few, in my opinion, failures in the book. There is no mention whatsoever of the Indian contributions to the evolution of algebra. This is important as it was Brahmagupta who, in the sixth century CE, introduced the full arithmetic of both positive and negative numbers and the full general solution of the quadratic equation. More importantly the Islamic algebraists took their knowledge of algebra from the Indians and in particular Brahmagupta. Another failure in this section is that Toscano repeats the standard myth of the House of Wisdom. Very positive is the fact that he explains the terminology of rhetorical algebra, the problems are all written out in words not symbols. He also explains that whereas we now just handle quadratic or cubic equations through the general form, in the Renaissance every variation was regarded as a separate equation. So, for example, if the x2 is missing from a cubic equation, this is a new equation that is handled separately. There are in fact, according to Omar Khayyam, fourteen different types of cubic equation. Apart from the omission of Indian algebra this whole chapter is excellent.

Toscano, The Secret Formula page 39

The third chapter takes us to the heart of the story and the event that made Tartaglia famous and would eventually lead to his bitter dispute with Cardano, the public contest with Antonio Maria Fior. In the most influential mathematics book of the era, his Summa de arithmetica, geometria, proportioni et proportionalita (Summary of arithmetic, geometry, proportions and proportionality) published in Venice in 1494, Luca Pacioli (c. 1447–1517) had stated that there was no possible general solution to the cubic equation, Fior had, however, acquired a general solution to the cubic equations of the form x3 + bx = c  and thought he could turn this into capital for his career. He challenged Tartaglia to a public contest thinking he held all the trumps. Unfortunately, for him Tartaglia had also found this solution, so the contest turned into a debacle for Fior and a great triumph for Tartaglia. If you want to know the details read the book. Toscano’s account of what happened, based on the available original sources is much more detailed and informative that the usual ones. We also get introduced to Messer Zuanne Tonini de Coi, another mathematician, who doesn’t usually get mentioned in the general accounts of the story but who plays a leading role in several aspects of it. Amongst other things, he was the first who tries to get Tartaglia to divulge the partial solution of the cubic that he has discovered, and it was he, who he first told Cardano about Tartaglia’s discovery.

In chapter four we meet the villain of the story the glorious, larger than life, Renaissance polymath, Gerolamo Cardano. We get a sympathetic description of Cardano’s less than auspicious origins and his climb to success as a physician against all the odds. Toscano does not over emphasise Cardano’s oddities and he had lots of those. We now get a very detailed account, once more based on original documents, of Cardano’s attempts to woo Tartaglia and seduce the secret of the partial cubic solution out of him. Cardano’s seduction was eventually successful, and he obtained the solution but only after swearing a solemn oath to reveal the solution to nobody until Tartaglia had published in his planned book. 

Chapter five takes us to Cardano’s breaking of that oath, his, I think justifiable reasons for doing so, and Tartaglia’s understandable outrage. The chapter opens with more exchanges about Tartaglia’s solution, which Cardano hasn’t truly understood, because of an error in Tartaglia’s encrypted poetical revelation of it. Having cleared this up Tartaglia begins to panic because Cardano is planning to publish a maths book his, Practica arithmetice et mensurandi singularis (The Practice of Arithmetic and Simple Mensuration), and he fears it will include his solution, it didn’t, panic over for now. We now get introduced to Cardano’s brilliant pupil and foster son, Lodovico Ferrari. Between the two of them, starting from Tartaglia’s solution, they find the general solutions of the cubic and the quartic or biquadratic equations putting algebra on a whole new footing but are unable to publish because of Cardano’s oath to Tartaglia. However, in 1542, Cardano and Ferrari travelled to Bologna and discovered in a notebook of Scipione Dal Ferro Tartaglia’s partial solution of the cubic made twenty years earlier than Tartaglia and obviously the source of Fior’s knowledge of the solution. Cardano no longer felt constrained by his oath and in 1545, his Ars Magna was published by Johannes Petreius in Nürnberg, containing all the algebra that he and Ferrari had developed but giving full credit to Scipione Dal Ferro and Tartaglia for their contributions. Tartaglia went ballistic!

The closing chapter deals with the final act, Tartaglia’s indignation over what he saw as Cardano’s treachery and the reaction to his accusations. Tartaglia raged and Cardano remained silent. Although, he had been very vocal in obtaining the cubic solution from Tartaglia, Cardano now withdrew completely from the dispute, leaving Ferrari to act as his champion. Tartaglia and Ferrari exchanged a total of twelve pamphlets, six each, full of polemic, invective, accusations, and challenges. Tartaglia trying, the whole time, to provoke Cardano into a direct response, accusing him of ghost-writing Ferrari’s pamphlets. Ferrari, in turn, constantly challenged Tartaglia to a face-to-face public confrontation, which he steadfastly rejected. Toscano reproduces a large amount of the contents of those pamphlets, upon which he judiciously comments. It is this engagement by the author that makes the book such a good read. Tartaglia finally caved in, probably as a condition of a new job offer, and met Ferrari in the public arena in Milan, fleeing the city on the evening of the first day of the confrontation, his reputation in tatters. What exactly took place, we don’t know, as Cardano and Ferrari never commented on the meeting, and we have only Tartaglia’s account that relates that he realised that the crowd was stacked against him with Ferrari’s supporters, and he could never win and so he departed.

Given the nature of the book, it has no illustrations. However, given the authors extensive use of both primary sources as well as authoritative secondary sources, it has an impressive number of endnotes, unfortunately not footnotes. Most of these are simple references to the source quoted and here the book uses a convention that I personally dislike. These references are mostly just something like [21.e]. The authors in the bibliography are sequentially numbered and if the author of more than one text these are identified by the small case letters. So, you are interested in the origin of a quote, you go to the endnotes, find there such a number, and then leaf through the bibliography to find out who, what, why, where! I do not like! Many of the items in the bibliography are texts from Italian historians, so the English edition has a short, but high quality, extra list of English titles on the topic. There is an excellent index.

It may seem that I have revealed too much of the contents of the book to make it worth reading but I have only sketched the outline of the story as it appears in the book, a story, which as I said at the beginning is very well know, the devil is as they say in the detail. By his very extensive use of the original sources, Toscano has given the popular story a whole new dimension, making his book a totally fascinating read for anybody interested in the history of mathematics. His book is also a masterclass in how to write high quality popular history of mathematics. 

[1] Fabio Toscano, The Secret FormulaHow a Mathematical Duel Inflamed Renaissance Italy and Uncovered the Cubic Equation, Translated by Arturo Sangalli, Princeton University Press, Princeton and Oxford, 2020

[2] More accurately the dastardly Karl Galle drew my attention to it, and I couldn’t resist the temptation, as it was not only cheap but came with free p&p. When I ordered it, I had forgotten that PUP distribute their book in Europe out of the UK. I try to avoid ordering books from the UK because, since Brexit, I now have to pay customs duty on book from the UK, on top of which the German postal service adds a €6 surcharge for paying the customs duty in advance, this would, in this case almost double the cost of the book. Normally, when I receive books from the UK, I get a note in my post box and have to go to the post office to pay the money due and pick up the book. For some reason, in this case, the postman simply delivered the book despite the label saying how much I was supposed to pay and so I didn’t have to pay it. You win some, you lose some!


Filed under Book Reviews, History of Mathematics, Renaissance Science

Mathematician, astrologer, conjurer! 

It is almost impossible to imagine a modern university without a large mathematics department and a whole host of professors for an ever-increasing array of mathematical subdisciplines. Mathematics and its offshoots lie at the centre of modern society. Because popular history of science has a strong emphasis on the prominent mathematicians, starting with Euclid and Archimedes, it is common for people to think that mathematics has always enjoyed a central position in the intellectual life of Europe, but they are very much mistaken if they do so. As I have repeated on several occasions, mathematics had a very low status at the medieval European university and led a starved existences in the shadows. Some people like to point out that the basic undergraduate degree at the medieval university formally consisted of the seven liberal arts, the trivium and quadrivium, with the latter consisting of the four mathematical disciplines–arithmetic, geometry, music, and astronomy. If fact, what was largely taught was the trivium–grammar, logic, rhetoric–and large doses of, mostly Aristotelian, philosophy. A scant lip service was paid to the quadrivium at most universities, with only a very low-level introductory courses being offered in them. There were no professors for any of the mathematical disciplines.

Things only began to change during the Renaissance, when the first universities, in Northern Italy, began to establish chairs for mathematics, which were actually chairs for astrology, because of the demand for astrology for medical students. The concept of general chairs for mathematics for all educational institutions began with Philip Melanchthon (1497–1560), when he set up the school and university system for Lutheran Protestantism, to replace the previously existing Catholic education system, in the second quarter of the sixteenth century.

Melanchthon in 1526: engraving by Albrecht Dürer Translation of Latin caption: «Dürer was able to draw Philip’s face, but the learned hand could not paint his spirit».
Source: Wikimedia Commons

Melanchthon did so because he was a passionate advocate of astrology and to do astrology you need astronomy and to do astronomy you need arithmetic, geometry, and trigonometry, so he installed the full package in all Lutheran schools and universities. He also ensured that the universities provided enough young academic mathematicians to fill the created positions.  

Catholic educational institutions had to wait till the end of the sixteenth century before Christopher Clavius (1538–1612) succeeded in getting mathematics integrated into the Jesuit educational programme and installed a maths curriculum into Catholic schools, colleges, and universities throughout Europe over several decades. He also set up a teacher training programme and wrote the necessary textbooks, incorporating the latest mathematical developments.

Christoph Clavius. Engraving Francesco Villamena, 1606 Source: Wikimedia Commons

England lagged behind in the introduction of mathematics formally into its education system. Even as late as the early eighteenth century, John Arbuthnot (1667–1735) could write that there was not a single grammar school in England that taught mathematics.

John Arbuthnot, by Godfrey Kneller Source: Wikimedia Commons

This is not strictly true because The Royal Mathematical School was set up in Christ’s Hospital, a charitable institution for poor children, in 1673, to teach selected boys’ mathematics, so that they could become navigators. At the tertiary level the situation changed somewhat earlier. 

Gresham College was founded in London under the will of Sir Thomas Gresham (c. 1519–1579) in 1595 to host public lectures.

Gresham College 1740 Source: Wikimedia Commons

Sir Thomas Gresham by Anthonis Mor Rijksmuseum

Amongst other topics, professors were appointed to hold lectures in both geometry and astronomy. As with the Royal Mathematical School a century later these lectures were largely conceived to help train mariners. The instructions for the geometry and astronomy professors were as follows:

The geometrician is to read as followeth, every Trinity term arithmetique, in Michaelmas and Hilary terms theoretical geometry, in Easter term practical geometry. The astronomy reader is to read in his solemn lectures, first the principles of the sphere, and the theory of the planets, and the use of the astrolabe and the staff, and other common instruments for the capacity of mariners.

The first university professorships for mathematics were set up at Oxford University in 1619 financed by a bequest from Sir Henry Savile (1549–1622), the Savilian chairs for astronomy and geometry.

Henry Savile Source: Wikimedia Commons

Over the years it was not unusual for a Gresham professor to be appointed Savilian professor, as for example Henry Biggs (1561–1630), who was both the first Gresham professor and the first Savilian professor of geometry.

Henry Briggs

Henry Savile was motivated in taking this step by the wretched state of mathematical studies in England. Potential mathematicians at Cambridge University had to wait until a bequest from Henry Lucas (c. 1610–1663), in 1663, established the Lucasian Chair of Mathematics, whose first incumbent was Isaac Barrow (1630–1677), succeeded famously by Isaac Newton (1642–1726 os).  This was followed in 1704 with a bequest by Thomas Plume to “erect an Observatory and to maintain a studious and learned Professor of Astronomy and Experimental Philosophy, and to buy him and his successors utensils and instruments quadrants telescopes etc.” The Plumian Chair of Astronomy and Experimental Philosophy, whose first incumbent was Roger Cotes (1682–1716).

unknown artist; Thomas Plume, DD (1630-1704); Maldon Town Council;

Before the, compared to continental Europe, late founding of these university chairs for the mathematical sciences, English scholars wishing to acquire instruction in advanced mathematics either travelled to the continent as Henry Savile had done in his youth or find a private mathematics tutor either inside or outside the universities. In the seventeenth century William Oughtred (1574–1660), the inventor of the slide rule, fulfilled this function, outside of the universities, for some notable future English mathematicians. 

William Oughtred by Wenceslas Hollar 1646

One man, who fulfilled this function as a fellow of Oxford University was Thomas Allen (1542–1632), who we met recently as Kenhelm Digby’s mathematics tutor.

Thomas Allen by James Bretherton, etching, late 18th century Source: wikimedia Commons

Although largely forgotten today Allen featured prominently in the short biographies of the Alumni Oxonienses of Anthony Wood (1632–1695) and the Brief Lives of John Aubrey (1626–1697), both of them like Allen antiquaries. Aubrey’s description reads as follows: 

Mr. Allen was a very cheerful, facecious man and everybody loved his company; and every House on their Gaudy Days, were wont to invite him. The Great Dudley, Early of Leicester, made use of him for casting of Nativities, for he was the best Astrologer of his time. Queen Elizabeth sent for him to have his advice about the new star that appeared in the Swan or Cassiopeia … to which he gave his judgement very learnedly. In those dark times, Astrologer, Mathematician and Conjuror were accounted the same thing; and the vulgar did verily believe him to be a conjurer. He had many a great many mathematical instruments and glasses in his chamber, which did also confirm the ignorant in their opinion; and his servitor (to impose on Freshmen and simple people) would tell them that sometimes he should meet the spirits coming up his stairs like bees … He was generally acquainted; and every long vacation he rode into the country to visit his old acquaintances and patrons, to whom his great learning, mixed with much sweetness of humour, made him very welcome … He was a handsome, sanguine man and of excellent habit of body.

The “new star that appeared in the Swan or Cassiopeia” is the supernova of 1572, which was carefully observed by astronomers and interpreted by astrologers, often one and the same person, throughout Europe.

Star map of the constellation Cassiopeia showing the position of the supernova of 1572 (the topmost star, labelled I); from Tycho Brahe’s De nova stella. Source: Wikimedia Commons

Conjuror in the Early Modern Period meant an enchanter or magician rather than the modern meaning of sleight of hand artist and was closely associated with black magic. Allen was not the only mathematician/astrologer to be suspected of being a conjuror, the same accusation was aimed at the mathematician astronomer, and astrologer, John Dee (1527–c. 1609). At one public burning of books on black magic at Oxford university in the seventeenth century, some mathematics books were reputedly also thrown into the flames. Aubrey also relates the story that when Allen visited the courtier Sir John Scudamore (1542–1623), a servant threw his ticking watch into the moat thinking it was the devil. The anonymous author of Leicester’s Commonwealth (1584), a book attacking Elizabet I’s favourite Robert Dudley, Earl of Leicester (1532–1588) accused Allen of employing the art of “figuring” to further the earl of Leicester’s unlawful designs, and of endeavouring by the “black art” to bring about a match between his patron and the Queen. The same text accuses both Allen and Dee of being atheists. 

Anthony Wood described Allen as:

… clarrissimus vir [and] very highly respected by other famous men of his time … Bodley, Savile, Camden, Cotton, Spelman, Selden, etc. … a great collector of scattered manuscripts …  an excellent man, the father of all learning and virtuous industry, an unfeigned lover and furtherer of all good arts and sciences.

The religious controversialist Thomas Herne (d. 17722) called Allen:

… a very great mathematician and antiquary [and] a universal scholar. 

In his History of the Worthies of Britain (1662), the historian Thomas Fuller (1608–1661) wrote of Allen:

…he succeeded to the skill and scandal of Friar Bacon [and] his admirable writings of mathematics are latent with some private possessors, which envy the public profit thereof.

The jurist John Selden (1584–1654), even in comparison with the historian William Camden (1551–1623), the diplomat and librarian Thomas Bodley (1545–1613) and the Bible translator and mathematician Henry Savile, called Allen:

…the brightest ornament of the famous university of Oxford.

So, who was this paragon of scholarship and learning, whose praises were sung so loudly by his notable contemporaries?

Thomas Allen was the son of a William Allen of Uttoxeter in Staffordshire. Almost nothing is known of his background, his family, or his schooling before he went up to Oxford. It is not known how, where, when, or from whom he acquired his knowledge of mathematics. He began acquiring mathematical manuscripts very early and there is some indication that he was largely an autodidact. He went up to Trinity College Oxford comparatively late, at the age of twenty in 1561. He graduated BA in 1563 and was appointed a fellow of Trinity 1565. He graduated MA in 1567. He might have acquired his mathematical education at Merton College. There is no indication the Allen was a Roman Catholic, but he joined an exodus of Catholic scholars from Trinity, resigning his fellowship, and moving to Gloucester Hall in 1570.

In 1598 he was appointed a member of a small steering committee to supervise and assist Thomas Bodley (1535–1613) in furnishing a new university library. Allen and Bodley had both entered Oxford at around the same time, graduating BA in the same year, and remained live long friends. Allen’s patrons all played a leading role in donating to the new library. About 230 of Allen’s manuscripts are housed in the Bodleian, 12 of them donated by Allen himself when the library was founded and the rest by Kenhelm Digby, who inherited them in Allen’s will. 

Through his patron, Robert Dudley, 1st Earl of Leicester, Allen came into contact with John Dee and the two mathematician/astrologers became friends.

Robert Dudley, 1st Earl of Leicester artist disputed Source: Wikimedia Commons

The Polish noble and alchemist Olbracht Łaski (d. 1604), who took Dee with him back to Poland in 1583, also tried to persuade Allen to travel with him to the continent, but Allen declined the invitation. 

Olbracht Łaski Source: Wikimedia Commons

In this time of publish or perish for academics, where one’s status as a scholar is measured by the number of articles that you have managed to get published, it comes as a surprise to discover that Allen, who, as we have seen from the quotes, was regarded as one of the leading English mathematicians of the age, published almost nothing in his long lifetime. His reputation seems to be based entirely on his activities as a tutor and probably his skills as a raconteur. 

As a tutor, unlike a Christoph Clavius for example, there is not a long list of famous mathematicians, who learnt their trade at his feet. In fact, apart from Kenelm Digby (1603–1665) the only really well-known student of Allen’s was not a mathematician at all but the courtier and poet Sir Philip Sidney (1554–1586) for whom he probably wrote a sixty-two-page horoscope now housed in the Bodleian Library.

Sir Philip Sidney, by unknown artist, National Portrait Gallery via Wikimedia Commons

He may have taught Richard Hakluyt (1553–1616) the promotor of voyages of explorations.

Hakluyt depicted in stained glass in the west window of the south transept of Bristol Cathedral – Charles Eamer Kempe, c. 1905. Source: Wikimedia Commons

He did teach Robert Fludd (1574–1637) physician and occult philosopher

Source: Wikimedia Commons

as well as Sir Thomas Aylesbury (1576–1657), who became Surveyor of the Navy responsible for the design of the warships.

This painting by William Dobson probably represents Sir Thomas Aylesbury, 1st Baronet.
Source: Wikimedia Commons

At the end of his life, he taught and influenced the German scientific translator and communicator, Theodore Haak (1605–1690), who only studied in Oxford between 1628 and 1631.

Portrait of Theodore Haak by Sylvester Harding.Source: Wikimedia Commons

As a member of Gloucester Hall, he tutored the sons of many of the leading, English Catholic families. In this role, he tutored several of the sons of Henry Percy, 8th Earl of Northumberland the highest-ranking Catholic aristocrat in the realm. He probably recommended the Gloucester Hall scholar, Robert Widmerpoole, as tutor to the children of Henry Percy, 9th Earl of Northumberland. Percy went on to become Allen’s patron sometime in the 1580s.

HENRY PERCY, 9TH EARL OF NORTHUMBERLAND (1564-1632) by Sir Anthony Van Dyck (1599-1641). The ‘Wizard Earl’ was painted posthumously as a philosopher, hung in Square Room at Petworth. This is NT owned. Source: Wikimedia Commons

Allen became a visitor to Percy’s Syon House in Middlesex, where he became friends with the mathematician and astronomer Thomas Harriot (c. 1560–1621), who studied in Oxford from 1577 to 1580.

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

When he died Harriot left instructions in his will to return several manuscripts that he had borrowed from Allen. Percy was an avid fan of the sciences known for his enthusiasm as The Wizard Earl. He carried out scientific and alchemical experiments and assembled one of the largest libraries in England. Allen with his experience as a manuscript collector and founder of the Bodleian probably advised Percy on his library. Harriot was not the only mathematician in Percy’s circle, he also patronised Robert Hues (1553–1632), who graduated from Oxford in 1578, Walter Warner (1563–1643), who also graduated from Oxford in 1578, and Nathaniel Torporley (1564–1632), who graduated from Oxford in 1581. Torporley was amanuensis to François Viète (1540–1603) for a couple of years. Torpoley was executor of Harriot’s papers, some of which he published together with Warner. All three of them were probably recommended to Percy by Allen. 

When Allen died, he had little to leave to anybody having spent all his money on his manuscript collection, which he left to Kenelm Digby, who in turn donated them to the Bodleian Library. But as we have seen he was warmly regarded by all who remembered him and, in some way, he helped to keep the flame of mathematics alive in England, at a time when it was burning fairly low. 


Filed under History of Mathematics, Renaissance Science, Uncategorized

The swashbuckling, philosophical alchemist

If you go beyond the big names, big events version of the history of science and start looking at the fine detail, you can discover many figures both male and female, who also made, sometime significant contribution to the gradual evolution of science. On such figure is the man who inspired the title of this blog post, the splendidly named Sir Kenelm Digby (1603–1665), who made contributions to a wide field of activities in the seventeenth century.

Kenelm Digby (1603-1665) Anthony van Dyck Source: Wikimedia Commons

To show just how wide his interests were, I first came across him not through my interest in the history of science, but through my interest in the history of food and cooking, as the author of an early printed cookbook, The Closet of the Eminently Learned Sir Kenelme Digbie Kt. Opened (H. Brome, London, 1669).

Source: Wikimedia Commons

Born 11 June in Gayhurst, Buckinghamshire, in 1603 into a family of landed gentry noted for their nonconformity, he, as we will see, lived up to the family reputation. His grandfather Everard Digby (born c. 1550) was a Neoplatonist philosopher in the style of Ficino, and fellow of St John’s College Cambridge, (Fellow 1573, MA 1574, expelled 1587), who authored a book that suggested a systematic classification of the sciences in a treatise against Petrus Ramus, De Duplici methodo libri duo, unicam P. Rami methodum refutantes, (Henry Bynneman, London, 1580, and what is considered the first English book on swimming, De arte natandi, (Thomas Dawson, London, 1587). The latter was published in Latin but translated into English by Christopher Middleton eight years later. 

Source: Wikimedia Commons
Source: Wikimedia Commons

His father Sir Everard Digby (c. 1578–1606) and his mother Mary Mulsho of Gayhurst were both born Protestant but converted to Catholicism.

Sir Everad Digby artist unknown Source: Wikimedia Commons

His father was executed in 1606 for his part in the Gunpowder Plot and Kenelm was taken from his mother and made a ward first of Archbishop Laud (1573–1645) and later of his uncle Sir John Digby (1508-1653), who took him on a sixth month trip (August 1617–April 1618) to Madrid in Spain, where he was serving as ambassador.

Sir John Digby portrait by Cornelis Janssens van Ceulen Source: Wikimedia Commons

Returning from Spain, the fifteen-year-old Kenelm entered Gloucester Hall Oxford, where he came under the influence of Thomas Allen (1542–1632).

Thomas Allen by James Bretherton, etching, late 18th century Source: wikimedia Commons

 Thomas Allen was a noted mathematician, astrologer, geographer, antiquary, historian, and book collector. He was connected to the circle of scholars around Henry Percy, Earl of Northumberland (1564–1632), the so-called Wizard Earl, through whom he became a close associate of Thomas Harriot (c. 1560–1621). Through another of his patrons Robert Dudley, Early of Leicester, (1532–1588) Allen also became an associate of John Dee (1527–c. 1608). Allen had a major influence on Digby, and they became close friends. When he died, Allen left his book collection to Digby in his will: 

… to Sir Kenelm Digby, knight, my noble friend, all my manuscripts and what other of my books he … may take a liking unto, excepting some such of my books that I shall dispose of to some of my friends at the direction of my executor.

Digby donated this very important collection of at least 250 items, which contained manuscripts by Roger Bacon, Robert Grosseteste, Richard Wallinford, amongst many others to the Bodleian Library.

Digby left Oxford without a degree in 1620, not unusual for a member of the gentry, and took off on a three-year Grand Tour of the continental. In France Maria de Medici (1575–1642) is said to have cast an eye on the handsome young Englishman, who faked his own death and fled France to escape her clutches. In Italy he became accomplished in the art of fencing. In 1623 he re-joined his uncle in Madrid, this time for a nearly a year and became embroiled in the unsuccessful negotiations to arrange a marriage between Prince Charles and the Infanta Maria. Despite the failure of this mission, when he returned to England in 1623, the twenty-year-old Kenelm was knighted by James the VI &I and appointed a Gentleman to Prince Charles Privy Chamber at the time converting to Anglicanism. In 1625 he secretly married his childhood sweetheart Venetia Stanley (1600–1633). They had two sons Kenelm (1626) and John (1627) before the marriage was made public. 

Venetia, Lady Digby by Anthony van Dyck Source: Wikimedia Commons

Out of favour with Buckingham, Digby now became the swashbuckler of the title. Fitting out two ships, the 400-ton Eagle under his command and the 250-ton Barque under the command of Sir Edward Stradling (1600–1644), he set off for the Mediterranean to tackle the problem of French and Venetian pirates, as a privateer, a pirate sanctioned by the crown.

Arbella, previously the Eagle Digby’s flagship

Capturing several Flemish and Dutch prize on route, on 11 June 1628 they attacked the French and Egyptian ships in the bay of Scanerdoon, the English name for the Turkish port of Iskender. Successful in the hard-fought battle, Digby returned to England with both ships loaded down with the spoils, in February 1629, where he was greeted by both the King and the general public as a hero. He was appointed a naval administrator and later Governor of Trinity House. 

The next few years were spent in England as a family man surrounded by a circle of friends that included the poet and playwright Ben Johnson (1572–1637), the artist Anthony van Dyck (1599–1641), the jurist and antiquary John Seldon (1584–1654), and the historian Edward Hyde (1609–1674) amongst many others. Digby’s circle of friends emphasises his own scholarly polymathic interests. His wife Venetia, a notable society beauty, died unexpectedly in 1633 and Digby commissioned a deathbed portrait and from van Dyck and a eulogy by Ben Johnson, now partially lost. 

Venetia Stanley on her Death Bed by Anthony van Dyck, 1633, Dulwich Picture Gallery Source: Wikimedia Commons

Digby stricken by grief entered a period of deep mourning, secluding himself in Gresham College, where he constructed a chemical laboratory together with the Hungarian alchemist and metallurgist János Bánfihunyadi (Latin, Johannes Banfi Hunyades) (1576–1646), where they conducted botanical experiments. 

In 1634, having converted back to Catholicism he moved to France, where he became a close associate of René Descartes (1596–1650). He returned to England in 1639 and became a confidant of Queen Henrietta Maria (1609–1669) and becoming embroiled in her pro-Catholic politics made it advisable for him to return to France.

Henrietta Maria portrait by Anthony van Dyck Source: Wikimedia Commons

Here he fought a duel against the French noble man Mont le Ros, who had insulted King Charles, and killed him. The French King pardoned him, but he was forced to flee back to England via Flanders in 1642. Here he was thrown into goal, however his popularity meant that he was released again in 1643 and banished, so he returned to France, where he remained for the duration of the Civil War.

Henrietta Maria established a court in exile in Paris in 1644 and Digby was appointed her chancellor. In this capacity he undertook diplomatic missions on her behalf to the Pope. Henrietta Maria’s court was a major centre for philosophical debates with William Cavendish, the Earl of Newcastle, his brother Charles both enthusiastic supporters of the new sciences, William’s second wife Margaret Lucas, who had been one of Henrietta Maria’s chamber maids and would go on to great notoriety as Margaret Cavendish prominent female philosopher, Thomas Hobbes, and from the French side, Descartes, Pierre Gassendi (1592–1655), Pierre Fermat (1607–1665), and Marin Mersenne. Digby was in his element in this society.

Margaret Cavendish and her husband, William Cavendish, 1st Duke of Newcastle-upon-Tyne portrait by Gonzales Coques Source: Wikimedia Commons

After unsuccessfully trying to return to England in 1649, in 1653, he was granted leave to return, perhaps surprisingly he became an associate of Cromwell, whom he tried, unsuccessfully, to win for the Catholic cause. He spent 1657 in Montpellier to recuperate, but returned to England in 1658, where he remained until his death. 

He now became friends with John Wallis (1616–1703), Robert Hooke (1635–1703), and Robert Boyle (1627–1691) and was heavily involved in the moves to form a scientific society, which would lead to the establishment of the Royal Society of which he was a founder member. On 23 January 1660/61 he read his paper A discourse concerning the vegetation of plants before the founding members of the Royal Society at Gresham College, which was the first formal publication to be authorised by that still unnamed body. The Discourse would prove to be his last publications, as his health declined, and he died in 1665.

Source: Wikimedia Commons

Up till now the Discourse is the only publication that I’ve mentioned, but it was by no means his only one. Digby was a true polymath publishing works on religion, A Conference with a Lady about choice of a Religion(1638), Letters… Concerning Religion (1651), A Discourse, Concerning Infallibility in Religion (1652). Autobiographical writings including, Articles of Agreement Made Betweene the French King and those of Rochell… Also a Relation of a brave and resolute Sea Fight, made by Sr. Kenelam Digby (1628), and Sr. Kenelme Digbyes honour maintained (1641). Critical writings on Sir Thomas Browne, Observations upon Religio Medici (1642), and on Edmund Spencer, Observations on the 22. Stanza in the 9th Canto of the 2d. Book of Spencers Faery Queen (1643). 

What, however, interests us here are his “scientific” writings. The most extensive of these is his Two Treatises, in One of which, the Nature of Bodies; in the Other, the Nature of Mans Soule, is looked into: in way of discovery, of the Immortality of Reasonable Soules originally published in Paris in 1644 but with further editions published in London in 1645, 1658, 1665, and 1669. Although basically still Aristotelian, this work shows the strong influence of Descartes and contains a positive assessment of Galileo’s Two New Sciences, which was still relatively unknown in England at the time. It also contains a form of mechanical atomism, which, however, is different to those of Epicure or Descartes.


Digby’s most controversial work was his A late discourse made in solemne assembly … touching the cure of wounds by the powder of sympathy, originally published in French in 1658 and then translated into English in the same year. This was a discourse that Digby had held publicly in Montpellier during his recuperation there.


This was a variation on Weapon Salve, an ointment that was applied to the weapon that caused a wound rather than to the wound itself. Digby was by no means the first to write positively about this supposed cure. It has its origins in the theories of Paracelsus and the Paracelsian physician Rudolph Goclenius the Younger (1572–1621), professor at the University of Marburg, first published on it in his Oratio Qua defenditur Vulnus Non Applicato Etiam Remedio, in 1608. In England the divine William Forster (born 1591), the physician and alchemist Robert Fludd (1574–1637), and the philosopher Francis Bacon (1561–1626) all wrote about it before Digby, but it was Digby’s account that attracted the most attention and ridicule. In 1687, an anonymous pamphlet suggested using it to determine longitude. A dog would be wounded with a blade and placed aboard a ship before it sailed. Then every day at noon the weapon salve would be applied to the blade causing the dog to react, thus tell those on board that it was noon at their point of departure. 

Also in 1658, John Wallis dedicated his Commercium epistolicum to Digby who was also author of some of the letters it contained.

John Wallis by Sir Godfrey Kneller Source: Wikimedia Commons

In 1657, Wallis had published his Arithmetica Infinitorum, an important contribution to the development of calculus.


Digby brought the book to the attention of Pierre Fermat and Bernard Frénicle de Bessy (c. 1604 – 1674) in France, Fermat wrote a letter to the English mathematician, posing a series of problems to be solved. Wallis and William Brouncker (1620–1684), who would later become the first president of the Royal Society, took up the challenge and an enthusiastic exchange of views developed between the French and English mathematicians, with Digby acting as conduit for the correspondence. Wallis collected the letter together and published them as his Commercium epistolicum

As already stated, A discourse concerning the vegetation of plants was Digby’s final publication and was to some extent his most interesting. Digby was interested in the question of how to revive dying plants and his approach was basically alchemical. He argued that saltpetre was necessary to the process of revival and that it attracted vital air, which is the food of the lungs. He is very obviously here close to discovering oxygen and in fact he supports his argument with the information that Cornelius Drebbel had used saltpetre to refresh the air in his submarine. In the paper he also hypothesises something very close to photosynthesis. Others such as Jan Baptist van Helmont (1580–1644) were conducting similar investigations at the time. These early investigations would lead on in the eighteenth century to the work of Stephen Hales (1677–1761) and the pneumatic chemists of the eighteenth century. 

Digby made no major contributions to the advancement of science, but he played a central role as facilitator and mediator between groups of philosophers, mathematicians, and scientists promoting and stimulating discussions in both France and England in the first half of the seventeenth century. He also played an important role in raising the awareness in England of the works of Descartes and Galileo. Although largely forgotten today, he was in his own time a respected member of the scientific community.

Digby is best remembered, today, for two things, his paper on the powder of sympathy, which I dealt with above, and his cookbook, to which I will now return. The Closet of the Eminently Learned Sir Kenelme Digbie Kt. Opened was first published posthumously by one of his servants in 1669 and has gone through numerous editions down to the present day, where it is regarded as a very important text on Early Modern food history. However, this was only one part of his voluminous recipe collection. Two other parts were also published posthumously. Choice and experimental receipts in physick and chirugery was first published in 1668 and went through numerous editions and translation by 1700, and A choice collection of rare chymical secrets and experiments in philosophy first published in 1682, which also saw many editions. What we have here is not three separate recipe collections covering respectively nutrition, medicine, and alchemy but three elements of a related recipe spectrum. We find a similar convolute in the work of Katherine Jones, Viscountess Ranelagh (1615–1691), Robert Boyle’s sister, an alchemist/chemist in her own right and an acquaintance of Digby’s. 

There is little doubt in my mind that Sir Kenelm Digby Kt. was one of the most fascinating figures of the seventeenth century, a century rich in fascinating figures. 

As was also believed when he died on his birthday in 1665, his epitaph read

‘Under this Tomb the Matchless Digby lies;

Digby the Great, the Valiant, and the Wise:

The Ages Wonder for His Nobel Parts;

Skill’d in Six Tongues, and Learn’d in All the Arts.

Born on the Day He Dy’d, Th’Eleventh of June,

And that Day Bravely Fought at Scanderoun.

‘Tis Rare, that one and the same Day should be

His Day of Birth, of Death, and Victory.’


Filed under History of Alchemy, History of Chemistry, History of Mathematics, History of science

NIL deGrasse Tyson knows nothing about nothing

They are back! Neil deGrasse Tyson is once again spouting total crap about the history of mathematics and has managed to stir the HISTSCI_HULK back into butt kicking action. The offending object that provoked the HISTSCI_HULK’s ire is a Star Talk video on YouTube entitled Neil deGrasse Tyson Explains Zero. The HISTSCI_HULK thinks that the title should read Neil deGrasse Tyson is a Zero!

You simple won’t believe the pearls of wisdom that NdGT spews out for the 1.75 million Star Talk subscribers in a video that has been viewed more than one hundred thousand times. If there ever was a candidate in #histSCI for cancellation, then NdGT is the man.

 Before we deal with NdGT’s inanities, we need some basic information on number systems. Our everyday Hindu-Arabic number system is a decimal, that’s base ten, place value number system, which means that the value of a number symbol is dependent on its place within the number. An example:

If we take the number, 513 it is actually:

 5 x 10+ 1 x 101 + 3 x 100

A quick reminder for those who have forgotten their school maths, any number to the power of zero is 1. Moving from right to left, each new place represents the next higher power of ten, 100, 101, 102, 103, 104, 105, etc, etc. As we will see the Babylonians [as usual, I’m being lazy and using Babylonian as short hand for all the cultures that occupied the Fertile Crescent and used Cuneiform numbers] also had a place value number system, but it was sexagesimal, that’s base sixty, not base ten. It is a place value number system that requires a zero to indicate an empty place. There are in fact two types of zero. The first is simply a placeholder to indicate that this place in the number is empty. The second is the number zero, that which occurs when you subtract a number from itself.

Now on to the horror that is NdGT’s attempt to tell us the history of zero:

HISTSCI_HULK: Not suitable for those who care about the history of maths

 NdGT: I pick these based on how familiar we think we are about the subject and then throw in some things you never knew

HISTSCI_HULK: All NildGT throws in, in this video, is the contents of the garbage pail he calls a brain.

NdGT: For this segment, we’re gonna talk about zero … so zero is a number, but it wasn’t always a number. In fact, no one even imagined how to imagine it, why would you? What were numbers for?

Chuck Nice, Star Talk Host: Right, who counts nothing?

NdGT: Right, numbers are for counting … nobody had any use to count zero … For most of civilisation this was the case. Even through the Roman Empire…

 Here NdGT fails to distinguish between ordinal numbers, which label the place that object take in a list and cardinal numbers which how many things are in a collection or set. A distinction that at one point later will prove crucial.

HISTSCI_HULK: When it comes to the history of mathematics NildGT is a nothing

CN: They were so sophisticated their numbers were letters!

In this supposedly witty remark, we have a very popular misconception. Roman numerals were not actually letters, although in later mutated forms they came to resemble letters. Roman numbers are collections of strokes. One stroke for one, two strokes for two, and so one. To save space and effort, groups of strokes are bundled under a new symbol. The symbol for ten was a crossed or struck out stroke that mutated into an X, the symbol for five, half of ten, was the top half of this X that mutated into a V; originally, they used the bottom half, an inverted V.  The original symbol for fifty was ↓, which mutated into an L and so on. As the Roman number system is not a place value number system it doesn’t require a place holder symbol for zero. If Romans wanted to express total absence, they did so in words not numbers, nulla meaning none. This was first used in a mathematical context in the Early Middle Ages, often simply abbreviated to N. 

NdGT: [Some childish jokes about Roman numeral] … I don’t know if you’ve ever thought about this Chuck, you can’t write zero with Roman numerals. There is no symbol for zero.

The Roman number system is not a place value number system but a stroke counting system that can express any natural number, that’s the simple counting numbers, without the need for a zero. The ancient Egyptian number system was also a stroke counting system, whilst the ancient Greeks used an alpha-numerical system, in which letters do represent the numerals, that also doesn’t require a zero to express the natural numbers.

NdGT: It’s not that they didn’t come up with it, it’s the concept of zero was not yet invented. 

HISTSCI_HULK: I wish NildGT had not been invented yet

This is actually a much more complicated statement than it at first appears. It is true, that as far as we know, the concept of zero as a number had indeed not been invented yet. However, the verbal concept of having none of something had already existed linguistically for millennia. Imaginary conversation, “Can I have five of your flint arrowheads?” Sorry, I can’t help you, I don’t have any at the moment. Somebody came by and took my entire stock this morning.” 

Although the Egyptian base ten stroke numeral system had no zero, by about 1700 BCE, they were using a symbol for zero in accounting texts. Interestingly, they also used the same symbol to indicate ground level in architectural drawings in much the same way that zero is used to indicate the ground floor in European elevators. 

Also, the place holder zero did exist during the time of the Roman Empire. The Babylonian sexagesimal number system emerged in the third millennium BCE and initially did not have a zero of any sort. This meant that the number 23 (I’m using Hindu-Arabic numerals to save the bother of trying to format Babylonian ones) could be both 2 x 601 + 3 x 600 = 123 in decimal, or 2 x 602 + 3 x 600 = 7203 in decimal. They apparently relied on context to know which was correct. By about 700 BCE the first placeholder zero appeared in the system and by about 300 BCE placeholder zeros had become standard. 

During the Roman Empire, the astronomer Ptolemaeus published his Mathēmatikē Syntaxis, better known as the Almagest, around 150 CE, which used a weird number system. The whole number part of numbers were written in a ten-base system in Greek alphanumerical symbols, whereas fractional parts were written in the Babylonian sexagesimal number system, with the same symbols, with a placeholder zero in the form of small circle, ō.

HISTSCI_HULK NildGT now takes off into calendrical fantasy land.

NdGT: So, when they made the Julian calendar, that’s the one that has a leap day every four years, … That calendar … that anchored its starter date on the birth of Jesus, so this obviously came later after Constantine, I think that Constantine brought Christianity to the Roman Empire. So, in the Julian calendar they went from 1 BC, BC, of course, stands for before Christ, to AD 1, and AD is in Latin, Anno Domini the year of our Lord 1, and there was no year zero in that transition. So, when would Jesus have been born? In the mythical year between the two? He can’t be born in AD 1 cause that’s after and he can’t be born in 1 BC, because that’s before, so that’s an issue.

CN: I’ve got the answer, it’s a miracle.

The Julian calendar was of course introduced by Julius Caesar in AUC 708 (AUC is the number of years since the theoretical founding date of Rome) or as we now express it in 44 BCE. The Roman’s didn’t really have a continuous dating system, dating things by the year of the reign of an emperor. Constantine did not bring Christianity to the Roman Empire, he legalised it. Both Jesus and Christianity were born in Judea a province of the Roman Empire, so it was there from its very beginnings. For more on Constantine and Christianity, I recommend Tim O’Neill’s excellent History for Atheists Blog. 

To quote myself in another blog post criticising NdGT’s take on the Gregorian calendar

The use of Anno Domini goes back to Dionysius Exiguus (Dennis the Short) in the sixth century CE in his attempt to produce an accurate system to determine the date of Easter. He introduced it to replace the use of the era of Diocletian used in the Alexandrian method of calculating Easter, because Diocletian was notorious for having persecuted the Christians. Dionysius’ system found very little resonance until the Venerable Bede used it in the eight century CE in his Ecclesiastical History of the English People. Bede’s popularity as a historian and teacher led to the gradual acceptance of the AD convention. BC created in analogy to the AD convention didn’t come into common usage until the late seventeenth century CE. [Although BC does occur occasionally in late medieval chronicles.]

As NdGT says Anno Domini translates as The Year of Our Lord, so Jesus was born in AD 1 the first year of our Lord, simple isn’t it. 

I wrote a whole blog post about why you can’t have a year zero, but I’ll give an abbreviated version here. Although we speak them as cardinal numbers, year numbers are actually ordinal numbers so 2022 is the two thousand and twenty second year of the Common Era. You can’t have a zeroth member of a list. The year zero is literally a contradiction in terms, it means the year that doesn’t exist. 

HISTSCI_HULK You can’t count on NilDGT

NdGT: So now, move time forward. Going, it was in the six hundreds, seven hundreds, I’ve forgotten exactly when. In India, there were great advances in mathematics there and they even developed the numerals, early versions of the numerals we now use, rather than Roman numerals. Roman numerals were letters [no they weren’t, see above], these were now symbolic shapes that would then represent the numbers. In this effort was the hint that maybe you might want a zero in there. So, we’re crawling now before we can walk, but the seeds are planted. 

We have a fundamental problem dating developments in Hindu mathematics because the writing materials they used don’t survive well, unlike the Babylonian clay tablets. The decimal place value number system emerged some time between the first and fourth centuries CE. The symbols used in this system evolved over a long period and the process is too complex to deal with here. 

The earliest known reference to a placeholder zero in Indian mathematics can be found throughout a commercial arithmetic text written on birch bark, the Bakhshali manuscript, the dating of which is very problematical and is somewhere between the third and seventh centuries CE. 

The Aryasiddhanta a mathematical and astronomical work by Āryabhaṭa (476–550 n. Chr.) uses a decimal place value number system but written with alphanumerical symbols and without a zero. The Āryabhaṭīyabhāṣya another mathematical and astronomical work by Bhāskara I (c. 600–c. 680 n. Chr.) uses a decimal place value number system with early Hindu numerals and a zero. With the Brāhmasphuṭasiddhānta an astronomical twenty-four chapter work with two chapters on mathematics by Brahmagupta (c. 598–c. 668 n. Chr.) we arrive out our goal. Brahmagupta gives a complete set of rules for addition, subtraction, multiplication, and division for positive and negative numbers, as well as for zero as a number. The only difference between his presentation and one that one might find in a modern elementary arithmetic text is that Brahmagupta tried to define division by zero, which as we all learnt in school is not defined, didn’t we? Far from being “hint that maybe you might want a zero in there” this was the real deal. 

HISTSCI_HULK: NildGT would be in serious trouble with the Hindu Nationalist propagators of Hindu science if they found out about his garbage take on the history of Hindu mathematics.

NdGT: These [sic] new mathematics worked their way to the Middle East. Baghdad specifically, a big trading post from all corners of Europe and Asia, and Africa and there it was. Ideas were put across the table. This was the Golden Age of Islam, major advances were made in all…in engineering, in astronomy, in biology, physiology, and vision. The discovery that vision is a passive phenomenon not active. So, all of this is going on and zero was perfected. They called those numerals Hindu numerals; we today call them Arabic numerals. 

What NdGT doesn’t point out is that the Golden Age of Islam lasted from about 700 to 1600 CE and took place in many centres not just in Baghdad. The Brāhmasphuṭasiddhānta was translated into Arabic by Ibrahim ibn Habib ibn Sulayman ibn Samura ibn Jundab al-Fazri (ges. 777 n. Chr.), Muhammad ibn Ibrahim ibn Habib ibn Sulayman ibn Samura ibn Jundab al-Fazri (ges. c. 800 n. Chr.), and Yaʿqūb ibn Ṭāriq (ges. c. 796 n. Chr.) in about 770 CE. This meant that Islamicate[1] mathematical scientists had a fully formed correct theory of zero and negative numbers from this point on. They didn’t develop it, they inherited it. 

Today, people refer to the numerals as Hindu-Arabic numerals!

NdGt: So, this is the full tracking because in the Middle East algebra rose up, the entire arithmetic and algebra rose up invoking zero and you have negative numbers, so mathematics is off to the races. Algebra is one of the very common words in English that has its roots in Arabic. A lot of the a-l words, a-l is ‘the’ in Arabic as I understand it. So, algebra, algorithm, alcohol these are all traceable to that period. … So, I’m saying just consider how late zero came in civilisation. The Egyptian knew nothing of zero [not true, see above]. 

The Persian mathematician Muḥammad ibn Mūsā al-Khwārizmī (c. 780–c. 850) wrote a book on the Hindu numeral system of which no Arabic text is known, but a Latin translation Algoritmi de Numero Indorum was made in the twelfth century. The word algorithm derives from the Latin transliteration Algoritmi of the name al-Khwārizmī. He wrote a second book al-Kitāb al-Mukhtaṣar fī Ḥisāb al-Jabr wal-Muqābalah (c. 82O), the translation of the title is The Compendious Book on Calculation by Completion and Balancing. The term al-Jabr meaning completion or setting together became the English algebra. 

The first time I heard this section I did a double take. “The entire arithmetic and algebra rose up invoking zero and you have negative numbers, so mathematics is off to the races”, you what! Ancient cultures had been doing arithmetic since at least three thousand years BCE and probably much earlier. I can’t do a complete history of algebra in this blog post but by the early second millennium BCE the Babylonians could solve linear equations and had the general solution to quadratic equations but only for positive solutions as they didn’t have a concept of negative numbers. The also could and did solve some cubic equations. In the middle of the first millennium BCE they had astronomical algorithms to predict planetary orbits, as well as lunar and solar eclipses. Brahmagupta’s work includes the general solution of linear equations, and the full general solution of quadratic equations, as we still teach it today. NdGT’s statement is total rubbish.

Of historical interest in the fact that although Islamicate mathematical scientists acquired negative numbers from Brahmagupta, they mostly didn’t use them, regarding them with scepsis 

HISTSCI_HULK: NildGT is off with the fairies

CN: What is this that I hear about the Mayans and zero?

NdGT: I don’t fully know my Mayan history other than that they really worshipped Venus, so their calendar was Venus based. The calendar in ancient Egypt was based on the star Sirius [something unintelligible about new year]. It’s completely arbitrary when you say the new year’s just began. Pick a date whatever matters in your culture and call it new year. Even today when is the Chinese New Year, it’s late January, February. Everybody’s got a different starter date.

The Mayan culture developed a vigesimal, base twenty, place value number system, which included a placeholder zero, independent of the developments in the Middle East and India. The Dresden Codex, one of the most important Maya written documents contains a mixture of astronomy, astrology, and religion, in which observations of Venus play a central role. The first day of Chinese New Year begins on the new moon that appears between 21 January and 20 February

HISTSCI_HULK: I’d worship Venus, she was a very beautiful lady

CN: The Jewish New Year is another new year that…

NdGT: Everybody’s got another new year. The academic calendar’s got a new year that’s September the first…

I assume that NdGT is referring to the US American academic calendar, other countries have different academic years. In Germany where I live, each German state has a different academic year, in order to avoid that the entire population drive off into their summer holidays at the same time. 

NdGT: …and by the way one quick question you’ve got a hundred dollars in your bank account, and you go and withdraw a hundred dollars from the cash machine and the bank tells you what?


So, here’s the thing, you have no money left in the bank and that’s bad, but what worse is to have negative money in the bank and so this whole concept of negative numbers arose and made complete sense once you pass through zero. Now instead of something coming your way, you now owe it. The mathematics began to mirror commerce and the needs of civilisation, as we move forward, because we are doing much more than just counting. 

CN: So, this is like the birth of modern accounting. Once you find zero that’s when you’re actually able to have a ledger that shows you minuses and pluses and all that kind of stuff.

One doesn’t need negative numbers in order to do accounting. In fact, the most commonly used form of accounting, double entry bookkeeping, doesn’t use negative numbers; credits and debits are both entered with positive numbers. 

Numbers systems and arithmetic mostly have their origin in accounting. The Babylonians developed their mathematics in order to do the states financial accounting. 

HISTSCI_HULK: There’s no accounting for the stupidity in this podcast

NdGT: So now we’re into negatives and this keeps going with math and you find other needs of culture and civilisation, where whole other branches of math have to be developed and we got trigonometry. All those branches of math where you thought the teacher was just being angry with you giving you these assignments, entire branches of math zero started it all. Where it gives you deeper insights into the operations of nature. 

I said I did a double take when NdGT claimed that arithmetic and algebra first took off when the Islamic mathematicians developed zero and negative numbers, which of course they didn’t, but his next claim completely blew my mind. So now we’re into negatives and this keeps going with math and you find other needs of culture and civilisation, where whole other branches of math have to be developed and we got trigonometry. I can hear Hipparchus of Nicaea (c. 190–c. 120) BCE, who is credited with being the first to develop trigonometry revolving violently in his grave.

HISTSCI_HULK: I could recommend some good books on the history of trigonometry, do you think NildGT can read?

There is another aspect to the whole history of zero that NdGT doesn’t touch on, and often gets ignored in other more serious sources. The ancient cultures that didn’t develop a place value number system, didn’t actually need zero. Almost all people in those cultures, who needed to do and did in fact do arithmetical calculations, didn’t do their calculation by writing them out step for step as we all learnt to do in school, they did them using the oldest analogue computer, the abacus or counting board. The counting board was the main means of doing arithmetical calculation from some time a couple of thousand years BCE, we don’t know exactly when, all the way down to the sixteenth century CE. An experienced and skilled user of the counting board could add, subtract, multiply, divide and even extract square roots much faster than you or I could do the same calculations with paper and pencil. 

The lines or column on a counting board represent the ascending powers of ten in a decimal place value number system, powers of sixty on a Babylonian counting board. During a calculation, an empty line or column represents an implicit zero. In fact, there is one speculative theory that realising this led someone to make that zero explicit when writing out the results of a calculation and that is how the zero came into existence. Normally, when using a counting board only the initial problem and the result are recorded in writing and if one is using a stroke collection, ancient Romans and Egyptians, or an alphanumerical, ancient Greeks, as well as ancient Indian and Arabic cultures before they adopted Hindu numerals, number system, then, as already noted above, you don’t need a zero to express any number. 

This blog post is already far too long but before I close a personal statement. I am baffled as to why a supposedly intelligent and highly educated individual such as Neil deGrasse Tyson chooses to pontificate publicly, to a large international audience, on a topic that he very obviously knows very little about, without taking the trouble to actually learn something about the topic before he does so. Maybe the fact that the podcast is heavily sponsored and littered with commercial advertising is the explanation. He’s just doing in for the money.

His doing so is an insult to his listeners, who, thinking he is some sort of expert, believe the half-digested mixture of half-remembered half-facts and made-up rubbish that he spews out. It is also a massive insult to all the historian of mathematics, who spent their lives finding, translating, and analysing the original documents in order to reconstruct the real history. 

HISTSCI_HULK: If I were a teacher and he had handed this in as an essay, I wouldn’t give him an F, I would give it back to him, tell him to burn it, and give him a big fat ZERO!

[1] Islamicate is the preferred adjective used by historians for mathematics and science produced under Islamic hegemony and published mostly in Arabic. It is used to reflect that fact that those producing it were by no means only Arabs or indeed Muslim


Filed under History of Mathematics, Myths of Science