Magnetic Variations – VIII Magnetists at War

In the years following the publication of De Magnete in 1600 and the death of William Gilbert in 1603 a dispute developed between two leading English magnetists, William Barlow (1544 – 1625) and Dr Mark Ridley (1560–c. 1624), as to which of them was Gilbert’s true disciple. 

We have already met William Barlow, son of a bishop, who was a successful career Church of England cleric, who never went to sea but became an expert on magnetism and navigation and was especially known for his mariner’s compass and variation compass designs. In 1605, he was appointed tutor and chaplain to Henry Frederick, Prince of Wales (1594–1612). Later, 1608 or 1609, the mathematician Edward Wright (1561–1615) was also appointed a tutor of  Henry Frederick. Both Barlow and Wright were closely involved in the genesis of William Gilbert’s De Magnete. Barlow had also published a demonstration of Wright’s Mercator projection “obtained of a friend of mone of like professioin unto myself,” in his The Navigator’s Supply (1597). Both men lost  their positions as tutor, when Henry Frederick died.

Prince Henry Frederick Portrait by Robert Peake the Elder, c. 1610 Source: Wikimedia Commons

We now leave Barlow for the moment and turn our attention the Mark Ridley, who we first met as one of the residents of Gilbert’s Wingfield house in London. In many ways Ridley’s career paralleled that of his erstwhile landlord. Ridley was born the second son of the six children of the Lancelot Ridley rector of Stretham in Cambridgeshire. Lancelot Ridley was an early prominent Protestant, promoted under Thomas Cranmer and favoured  during the reign of Edward VI. He was subsequently deprived under Mary but rose again to prominence under Elizabeth I. Mark matriculated as a pensioner at Claire College Cambridge in 1577, graduating BA in 1581 and MA in 1584. He was licenced to practice medicine by the College of Physicians in 1590 and graduated MD in 1592.

Mark Ridley Source

On 27 May 1594 he was appointed by Elizabeth, on the recommendation of William Cecil, to serve Feodor Ivanovich, the tsar of Russia as physician.

Tzar Feodar I Source: Wikimedia Commons

He worked for five years in Moscow and on the death of Tsar Feodor in 1599, he was appointed physician to of his successor, Boris Godunov. Elizabeth requested that he be allowed to return to London in that year and Boris Godunov wrote to her commending him for his faithful service and releasing him. 

Ridley became an active member of the College of Physicians and like Gilbert before him rose in their ranks, being elected censor in 1607. Over the years he was regularly elected to various offices in the organisation. Interestingly, Ridley is perhaps more significant as the author of the two Russian-English dictionaries than for his writings on magnetism. 

While living in Russia between 1594 and 1599, he compiled two manuscript dictionaries of Russian: a Russian-English dictionary of 7,203 entries entitled A dictionarie of the vulgar Russe tongue and an English-Russian dictionary of 8,113 entries entitled A dictionarie of the Englishe before the vulger Russe tonnge. The former includes a short grammar of Russian on the first eight folios. Both dictionaries are now held at theBodleian Library at the University of Oxford (MSS Laud misc. 47a and 47b). (Wikipedia)

Gilbert’s De Magnete was, of course, not without its critics. But in the early phase things remained fairly quiet, especially in England, where the book and its author were much admired. However, between 1603 and 1604 the splendidly named and titled Guillaume de Nautonier, sieur de Castel-Franc au haut Languedoc, Géographe du roi Henri IV (1560– 1620)

Guillaume de Nautonier

 published the equally splendidly titled: 

Mecometrie de leymant cest a dire La maniere de mesurer les longitudes par le moyen de l’eymant. Par laquelle est enseigné, un tres certain moyen, au paravant inconnu, de trouver les longitudes geographiques de tous lieux,–aussi facilement comme la latitude. Davantage, y est monstree la declinaison de la guideymant, pour tous lieux. Œuvre nécessaire aux admiraux, cosmographes, astrologues, geographes, pilotes, geometriens, ingenieux, mestres des mines, architectes, et quadraniers. (The mecometry of the loadstone or the way to determining the longitude by means of the loadstone…)

In this work Le Nautonier accepts Gilbert’s claim that the Earth is a magnet but claims that he discovered this independently, although, unlike Gilbert, he offers no experiments or other proofs to back up his claim. He was the first to state that the Earth is a tilted dipole, giving 67°N and 67°S for their latitudes and by modern reckoning approximately 30°E and 150°W as their longitudes. He stated that the Earth was a perfect sphere, and, as the book title states, resurrected the already debunked theory that magnetic variation was regular and using it one could determine longitude. He devoted a lot of space to refuting Gilbert’s explanations of the irregularities in variation. Initially there was no reaction to this book in England, although it would be thoroughly debunked in France by Didier Dounot (1574–1640), professor for mathematics on the Académies du roi, in his Confutation de l’invention des longitudes ou De la mecometrie de l’eymant. Cy devant mise en lumiere souz le nom de Guillaume le Nautonnier, sieur de Castel-Franc au haut Languedoc (1611)

The first reactions in England were triggered in 1608 by the publication by Anthony Linton, chaplain to Charles, Lord Howard of Effingham, who served as High Admiral from 1585–1618, of his Newes of the Complement of the Art of Navigation. And of the Mightie Empire of Cataia Together with the Straits of Anian.

In this rather strange volume, Linton, “after citing the criticisms of the art of navigation of Humphrey Gilbert, Thomas Digges, William Borough, Richard Polter, and Edward Wright, whose chart he praised, he pointed out that in navigation position-finding was still imperfect.”^[1] Rather stating the obvious. He then claimed that any navigator could ‘make his conclusions of Latitude, Longitude, and Variation,’ as accurately ‘as is possible to be done in any other Mathematicall practice in use amongst us’ by ‘continued observation’, and by exploiting the existence of the two magnetic poles. By the use of certain globes and charts of his devising, obtainable at a price, and ‘in six other ways’, the navigator, knowing , ‘the vaiation of the Compasse and the Latitude of the place’  would find out by Aritmeticall calculation the true longitude of the same place’. However, for the satisfactory working of this admirable but obscurely worded system there appeared to be one serious drawback only, namely, that it required ‘professors of greater skill and practice in the Mathematics, then now commonly found’.^[2] This very jumbled account obviously preaches the same gospel as Le Nautonier’s early work and raises the question, whether Linton had plagiarised it, to which we don’t know the answer.

Both of Henry Frederick’s navigation tutors now responded to Linton and Le Nautonier’s arguments. De Magnete was written in Latin and first got translated into English in the nineteenth century. This meant that his theories were not accessible to the mariners who couldn’t read Latin. Barlow wrote a manuscript presenting and explaining Gilbert’s ideas on magnetism and the compass in English. In this work he argued against and debunked the theory propagated by  Linton and Le Nautonier. Barlow gave a copy of the manuscript to Sir Thomas Chaloner (1559–1615), a courtier and  Governor of the Courtly College for the household of Prince Henry Frederick, so basically Barlow’s employer as chaplain and tutor to the prince. Chaloner manage to lose this manuscript as well as a second copy that he had agreed to have published. This was the situation in 1615, when Chaloner died.

Monument of Sir Thomas Chaloner St Nicolas’ Church Chiswick

Edward Wright simply refuted the argument in an appendix to the expanded second edition of his Certaine Errors in Navigation, arising either of the Ordinarie Erroneous Making or Vsing of the Sea Chart, Compasse, Crosse Staffe, and Tables of Declination of the Sunne, and Fixed Starres Detected and Corrected published in 1610, in which he listed the observed variation in many places. The volume was dedicated to “THE HIGH AND MIGHTIE PRINCE HENRY; eldest Son to our soueraigne Lord King Iames: Prince of Wales, Duke of Cornwell, Earle of Chester, &c.”

Ridley entered the fray in 1613 with the publication of his first book on magnetism: 

A SHORT TREATISE of Magneticall Bodies and Motions. By Marke Ridley D^r in phisicke and Philosophie Latly Physition to the Emperour of Russia, and one of y^e eight principals or Elects of the Colledge of Physitions in London. London Printed by Nicholas Okes. 1613. 

Like Barlow he presented his theories in English for those who couldn’t read Latin. He debunked the various myths about the healing power of magnets etc and propagated the theories of Gilbert as presented in De Magnete. He then goes on to debunk the theories of Linton and Le Nautonier. After which he presents his own incorrect theory:

‘when travelling or sailing … it will be very necessary for thee to be stored with the Marriners Compasse for the sea … to know the way … and also to have the Inclinatory-needle truly placed in his ring, and the Directory needle, or a little flie Magneticall in the boxe, fastened at the bottome … for to know under what latitude thou art every day of thy voyage …’ Now one of the chief purposes of his book was to describe the benefits that would arise from the use of ‘the Directory-Magneticall-needle … for the description of Ports, Havens, Forelands, Capes, Bayes, and Rivers, for the more perfect making of Sea-cardes … and all Mathematicall instruments for measuring and surveying …’ and to explain the manner of using it.  Yet the instrument was fundamentally unsound, for the mutual attraction and repulsion of the magnetical needles in close juxtaposition, such as he envisaged, foredoomed it to failure because of the resultant errors.^[3]

Ridley then goes on to deliver a wide ranging account of loadstones and compasses followed by the latest discoveries of Galileo and Kepler. He gives accounts of Gilberts theory of variation, Blagrave’s Mathematicall  Jewell, preferring Blagrave’s astrolabe to that of Gemma Frisius, accounts of the work of Wright, Brigg’s tables in Blunderville’s book, The Seven Planets, a description of a quadrant and the log-line etc, etc.

The publication of Ridley’s  Magneticall Bodies possibly inspired a fifth editions of Robert Norman’s The Newe Attractive and William Borough’s A Discourse on the Variation of the Cumpas in 1614 and it almost certainly prompted Barlow to publish his manuscript from 1609 in 1616 as: 

MAGNETICALL Aduertisements : or DIVERS PERTINENT  obserruations, and approued experiments concerning the nature and properties of the Load-stone: Very pleasant for knowledge, and most needful for practice, or trauelling, or framing of Instruments fir for trauellers both by Sea and Land. 

Act. 17.26 He hath made of one bloud all nations of men for to dwell on the face of the earth, and hath determined the times before appointed, and the bounds of theior habitation, that they should seeke the Lord, &c.

LONDON; Printed by Edward Griffin for Timothy Barlow, and are to be sold at his shop in Pauls Church-yard at the signe of the Bull-head. 1616. 

He didn’t name Ridley directly but referred to his “propositions set abroad in another man’s name and yet some of them not rightly understood by the partie usurping them.”^[4] He wrote:

I was the first that made the inclinatory instrument transparent to be used pendant, with a glass on both sides, and a ring at the top … and moreover I hanged him in a compass box, wjere with two onces weight he will be fit for use at sea. I first found out and showed the difference between iron and steel, and their tempers for magnetical uses … I was also the first that showed the right way of touching needles …^[5]

To demonstrate that he, not Ridley, was Gilbert’s heir he stated that he had been researching magnetism since 1576 and that Gilbert had appreciated his contributions. To prove this, he included a letter that Gilbert had sent to him in 1602. This is in fact the only letter of Gilbert’s that has survived:

To the Worshipfull my good friend, Mr. William Barlowe at Easton by Winchester.

Recommendations with many thanks for your paines and courtesies, for your diligence and enquiring, and finding diuers good secrets, I pray proceede with double capping your load-stone you speake of, I shall bee glad to see you, as you write, as any man, I will haue  any leisure, if it were a moneth, to conferre with you, you have shewed mee more–and brought more light than any man hath done. Sir, I will commend you to my L. of Effingham, there is heere a wise learned man, a Secretary of Venice, he came sent by that State, and was honourably received by her Majesty, he brought me a lattin letter from a Gentle-man of Venice that is very well learned, whose name is Iohannes Franciscus Sagredus, he is a great Magneticall man, and writeth that hee hath conferred with diuers learned men in Venice and with Readers of Padua, and reporteth wonderfull liking of my booke, you shall have a copy of the letter: Sir, I propose to adioyne an appendix of six or eight sheets of paper to my booke after a while, I am in hand with it of some new inuentions and I would haue some of your experiments, in your name and inuention put into it, if you please, that you may be knowen for an augmener of that art. So for this time in haste I take my leaue the xiiyth of February.

Your very louing friend,

W. Gilbert^[6]  

One major bone of contention between the two disciples of Gilbert was his embrace of Copernicanism with his assumption of a magnetic diurnal rotation of the Earth. As a conservative official of the Church, Barlow totally rejected this aspect of Gilbert’s work, remaining a staunch geocentrist. Ridley, however, going further than Gilbert, adopted a full heliocentric cosmology, as can be seen from his inclusion of the newest results from Galileo and Kepler in his book. 

Barlow’s veiled accusation of plagiarism did not escape Ridley and he responded with a pamphlet: Magneticall Animadversions. Made by Dr Mark Ridley, Doctor in Physicke. Upon certain Magneticall Advertisements, lately published, From Maister William Barlow.  (1617) His criticism was scathing:

‘There is almost no proposition in this book which most Mariners, Instrument-Makers, Compasse -makers, Cocke-makers, and Cutlers of the better and more understanding sort around London and the Suburbs have not known, practized, and made long before.’  His so-called inventions were ‘most of them in the Doctor Gilbert’s Booke, as I said before, or else such ordinary things that any ingenious workman hath or may easily invent or make; unles you hold all men Dulberts like your rare workman of Winchester.’^[7]

Barlow’s response came immediately in his, A Briefe Discovery of the Idle Animadversions of Marke Ridley (1618):

This time it was personal. He tried to discredit Ridley, suggesting that he had morally compromised himself in order to ‘in so short a time become [the Russian] Empoerors principall Physition.’ In a double entendre to Ridley’s observations or ‘looks’ with the new-fangled telescope, he insinuated that the youthful Ridley had seduced the Czar, ‘for his lookes … are his meanes.’^[8]

Ridley delivered a parting shot with his, Appendix or an Addition … unto his Magneticall Treatise in answer to M. Barlow (1618).

Despite Ridley’s attacks, Barlow reprinted his Magneticall Advertisements unchanged, except for a new title page, in 1618.

And so, the verbal war between the two heirs of William Gilbert ground to a halt. In their major publications, in this unpleasant exchange, both had made important contributions to the ongoing debate on magnetism and the compass, most importantly making much of Gilbert’s work accessible in English, for those unable to read Latin. However, at the same time they had made a public spectacle of themselves in their bitter dispute, a behaviour that was, unfortunately all too common amongst scholars during the Renaissance.  

---

^[1] David W. Waters, The Art of Navigation in England in Elizabethan and Early Stuart Times, Yale University Press, New Haven, 1958, p. 274. 

^[2] Waters pp.274-5.

^[3] Waters p. 334

^[4] Stephen Pumfrey, Latitude & The Magnetic Earth, Icon Books, Cambridge2003 p. 207

^[5] Waters p. 337

^[6] William Gilbert, De Magnete, trans. P. Fleury Motteley, Dover Books, NY, 1958, p. xxvi

^[7] Pumfrey, p. 209

^[8] Pumfrey, p. 209

Little things that made a big impact.

It is quite common that people get asked what they think is the most import development in technology or the most significant technological invention in human history. Apart from the ubiquitous wheel, which is almost certainly the most common answer, unless they are historians, they will almost always name something comparatively modern and usually big and impressive–the steam engine, the automobile, the airplane, the computer or whatever. However, having been at one time in my life, for a number of years, an archaeologist, I am very much aware of the massive impact that seemingly everyday things had on the development of human society–the most obvious is cooking with fire, but also making, ceramics, bricks, glass, simple tools, and many other things many of them seemingly small and insignificant. In response to a fascinating blog post by Rachel Laudan on the uses to which gourds were put in the history of cooking, I once wrote a blog post on the significance of the invention of the sewing needle. 

This being the case, I couldn’t resist when I came across reviews of Roma Agrawal’s book Nuts & Bolts and bought a copy, which I read with growing enthusiasm and delight. I couldn’t resist because the full title is Nuts & Bolts: Seven Small Inventions That Changed the World (in a Big Way).^[1]

Roma Agrawal is not a historian but a structural engineer, a graduate of Oxford University, BA physics, and Imperial college, MA Structural engineering, who has worked on major engineering project, including  the Shard in London. In her book she brings an engineer’s eyes to a popular historical view of the nail, the wheel, the spring, the magnet, the lens, string, and the pump. Outlining not only their origins, their evolution, the multiple forms they have taken and the multiple uses to which they have been put but also giving a soft scientific and engineering explanation of how they work in terms of forces and resistance. 

From the outset this book is wonderfully written and a delight to read. The world’s textbook writers could learn a lesson or two from Agrawal on how to hold a reader’s interest and entertain them whilst at the same time educating them. She makes it seem very easy. 

She starts with the nail, a very simple, small, seemingly insignificant everyday object that most people wouldn’t even think of when asked to list important historical invention. However, the nail is and has been a very important element in building projects of all sizes throughout the world for millennia. She traces its origins, its developments, and its very important transition from being hand forged to machine made.  She explains how the force of friction enables nails to hold things together. However, she doesn’t just deal with nails in this chapter but with screws, rivets, and nuts and bolts, which as she explains are all basically evolved forms of the humble nail. In this direction the mental leap that most surprised me is that the piles–wood, metal, concrete–driven into the ground to support building are in reality just very big nails.

After the nail, Agrawal turns to that perennial favourite greatest invention, the wheel. We of course get the wheel enabling transport but more significantly she takes her readers on a whirlwind tour of many of the other places where wheel can be found fulfilling an important function. We have the potter’s wheel,  cog wheels and gear wheels, the invention of the bicycle and the invention of the gyroscope. She includes a fascinating section on Josephine Cochran’s invention of the dishwasher. One facet of Agrawal’s narratives is that where possible she draws attention to the contributions made by women to the history of technology.  She takes us through the evolution of better wheels from the simple solid plank wheel down to the sophisticated spoked wheels of modern bicycles and closes by stating, “Human progress and the reincarnations of the wheel and axel are intricately intertwined. And that’s why we should absolutely continue to reinvent the wheel.”

Our next small invention is the humble spring, which doesn’t immediately spring to mind when asked about the greatest inventions. (I’ll let myself out!) One revelation that totally blew my mind when I first read it, is that the bow, as in bow and arrow, is a spring! If you want to know why the elaborately curved Mongolian bow is superior to the European longbow this is the place to go. Moving on via springs in guns Agrawal land at a device that lives from its springs the mechanical clock. Here we meet another aspect of Agrawal’s approach, hands on. The opening paragraphs of the nail section found her hand forging nails in a smithy, we now find in the workshop of Dr Rebecca Struthers, independent watchmaker and horologist. Struthers put out her own book Hands of Time: A Watchmaker’s History of Time (Hodder & Stoughton) in 2023. The lady engineer and the lady watchmaker take the reader through the history of the clock and the central role that springs came to play in their construction. John Harrison, of course, gets a nod on route. Fascinatingly the structural engineer introduces her readers to building, suspended on springs to protect them from earthquakes or to shield them from external vibrations. 

Our interest is now directed to the magnet, where it is not long before we get briefly introduced Dr William Gilbert and his De Magnete but we don’t linger, quickly progressing to the development in magnets and their materials now that magnetism had been established as a science. Having sketched the developed the modern magnet we get introduced to the electric telegraph, a massive communications revolution, that depended on magnets. The electric telegraph was superceded by the telephone another communications device dependent on the magnet. This capital argues for the magnet as the driver of modernity with the television following on the heels of the telegraph and telephone. Here Agrawal pulls another rabbit out of her hat, ignoring the western developers in favour of the story Takayanagi Kenjiro the independent Japanese inventor of the television. The section closes with the story of LEDs.

Up till now, whilst reading, I was really enjoying Agrawal’s fascinating and stimulating book and then I ran into her section on the lens, and soon wished I hadn’t. Readers of this blog will know that the history of optics is one of my special areas of study and I’m sorry but Agrawal’s story of the lens is a trainwreck! I’ll move on for now but return to the lens later.

As opposed to the chapter on the lens, the chapter on string is a delight. Agrawal opens with the steel cables that hold up suspension bridges, which is not what one normally thinks about when somebody uses the word string. However, as she points out the cables on smaller suspensions bridges, such as the one that was one of he first engineering projects, are twisted together out of steel fibres in exactly the same way as string is made by twisting together plant fibres. The heavier ones are made with a slightly different process but are also basically string. She then moves on to sewing and the sawing needle, sewing thread being, of course another form of string. Moving on we have cloth which is usually woven or knitted string. String has truly played a major roll in human history. The chapter closes with a discourse on music made with string instruments and instead of the violins or guitars, one might expect we get a fascinating detailed description on the tanpura, the drone instrument in Indian music, and how the strings are manipulated to produce the vibrating, droning sound. 

The final chapter is devoted to the pump, which Agrawal defines as a way of raising water to a higher level. After a brief sketch of the history of the water lifting devices, she turns to a description of the most fascinating of all pumps, the human heart. The heart is a small pump with an incredible performance. However, Agrawal is not deviating from engineering to biology but the description of the heart is used as an introduction to the story of the development of the heart-lung machine, a truly fascinating story of a piece of medical engineering history. After this excurse into the medical discipline we follow Agrawal into the equally fascinating story of the development of the breast milk pump, which Agrawal was led to through her own problems with breast feeding. 

We  return to the lens. This starts, as much of the book, with a personal anecdote about the conception of Agrawal’s daughter, which was by artificial insemination and a description of the microscope developed to study the insemination of ova. This is one of several personal stories in the book that illustrates Agrawal’s interest in the topic under discussion. Having introduced the lens through the microscope, we now move back to the origins and history of the lens, here she goes off the rails. She accepts that the so-called Nimrud  lenses (7^thcentury BCE) are lenses and not simply ground and polished pieces of lens shaped crystal, for which there is simply no proof whatsoever. I think they are more probably decorative stones.

She now moves on to the Greeks and writes the following:

The Greeks laid down some basic rules of how light reflects off mirrors and even bends through lenses.

The Greeks did indeed study the basics of refraction but those studies had almost nothing to do with lenses. The most extensive study of refraction was by Ptolemaeus, who was concerned with atmospheric refraction in astronomy and most important failed to determine the sine law of refraction.

Having quickly rubbished Greek theories of optics without going into detail we arrive at Ibn al-Haytham (b. 965 BCE). After a biographical sketch she makes the claim that “he finally explained correctly how sight works.” Although Ibn al-Haytham made great progress towards a correct explanation of how sight works, it is by no means completely correct and above all most of the elements he uses in his model are taken from the Greek sources that she doesn’t present. She then presents one of al-Haytham’s experiments claiming that it proves his theories, which it doesn’t. We then get the extraordinary statement:

Ibn al-Haytham’s work related to optics was groundbreaking for many reasons. For the first time, someone suggested correctly, that light exists independently of vision.

Sorry, but this is pure and utter garbage!

He also said that light travels in rays along straight lines, and these rays are not modified by other rays that cross their path.

This was already known to the Greeks.

For the first time, he conducted a scientific study of images formed by lenses.

Ibn al-Haytham did not conduct a scientific study of images formed by lenses. He made some minor comments on the images formed by spherical lenses. 

We then get the classic:

In another interesting link, physicist  Jim Al-Khalili writes that Ibn al-Haytham’s discussion on perspective-which was translated into Italian in the fourteenth century-enabled Renaissance artists to create the illusion of three-dimensional depth in their work. 

This illustrates a major problem in her work on al-Haytham, she uses the highly hagiographic and historically inaccurate work of Al-Khalili as her source, rather than the historically accurate, in depth studies of David C. Lindberg, A. Mark Smith, and A. I. Sabre. 

As far as the development of linear perspective during the Renaissance is concerned, the geometry of linear perspective is the optical geometry of Euclid, which is in no way dependent on anything al-Haytham wrote. Of the early developers of linear perspective Lorenzo Ghiberti (1378–1455) indeed quotes al-Haytham. However, we know nothing about the sources which inspired Filippo Brunelleschi (1377–1446) to carry out his famous demonstration of linear perspective. Finally, Mark Smith thinks that Leon Battista Alberti (1404–1472), who wrote and published the first explanation of linear perspective in his Della Pittura (1435)/De Pictura (1436) did not reference optical literature to write his book but that it was based on his work recording the architectural ruins in Rome using a plane table. More importantly, Alberti states clearly in his book that for linear perspective it is irrelevant whether one holds an extramission theory of optics, Euclid, or an intromission one, al-Haytham.  

We then get the claim that that Ibn al-Haytham “laid the foundation of what we now describe as scientific method.” As al-Haytham’s experimental programme is an extended copy of that of Ptolemaeus’ programme this claim is simply refuted. 

Following an explanation of how lenses work, we get a horrible piece of ahistorical garbage:

The science of optics advanced significantly in the Islamic empires, but the practical applications of lenses remained largely limited to burning glasses and simple magnification. Centuries later, when the Islamic Golden Age of science [my emphasis] began to dim in the Middle East, and as light began to break through the Dark Ages in the West, [my emphasis] Europe’s Renaissance thinkers built on the work of their medieval counterparts to truly harness the superpower of lenses.

The concept of the Islamic Golden Age of science is, today, increasingly viewed with scepticism by historians as it is particularly difficult to define just when it was supposed to have ended. The term Dark Ages, however, is not just viewed with scepticism but has been totally banned from the vocabulary of serious historical discussion. 

Having written this paragraph, Agrawal then dives straight into the invention of the microscope, strangely making here no mention of either the invention of eyeglasses (spectacles) or the telescope. This is particularly bizarre as a couple of pages earlier she had written, “ He [Ibn al-Haytham] laid the foundations for scientists after him – including Newton, who published his work 700 years later – to not only study and explain light even further, but also to engineer spectacles, microscopes, telescopes, cameras, and more.” Note Newton gets a name check but a whole list of other significant contributors to the history of optics, Kepler for example, don’t. Without the invention of spectacles, no industry of lens making would have developed, and without spectacles no telescope, and without the telescope no microscope! 

Interestingly, the earliest date for the end of the so-called Islamic Golden Age of science is the fall of Baghdad at the hand of the Mongols in 1258, which almost coincides with the invention of spectacles in Northern Italy, which by the way, was in no way connected to the optical theories of Ibn al-Haytham. 

We get a few lines on Robert Hooke and his Micrographia before she writes the following:

No doubt inspired by Hooke’s work, a Dutch shopkeeper with little formal education decided to look closer, leading him to seeing many things that humans had never seen before.

The Dutch shopkeeper is, of course Antony Leeuwenhoek, who was actually quite a bit more than just a shop keeper. There is actually no evidence that Leeuwenhoek was inspired by Hooke. This is a purely speculative theory proposed by Brian J. Ford, who is the source that Agrawal uses for he comments on Leeuwenhoek.     

There follows an account of Leeuwenhoek’s single lens microscopes which ends with the following:

Holding the microscope up to his eye, he could peer through his handmade lenses, some of which could magnify objects by an astonishing 266 times. To put this in perspective, the microscopes with two lenses invented in the late sixteenth century by the Dutch father and son team, Hans and Zacharias Janssen[my emphasis], could only magnify up to a maximum of ten times, because of the limited quality of the lenses and blurring effects first studied by Ibn al-Haytham. 

The claim that Hans and Zacharias Janssen invented the microscope in the sixteenth century was very dubious at the best when it was first presented, apart from anything else Zacharias Janssen would have been only four-years-old at the time given in the story. However, modern research by Huib Zuidervaaart, has shown that Zacharias Janssen, who is also credited with the invention of the telescope, had nothing whatsoever to do with optics before 1616. 

We don’t actually know who invented the microscope but it is assumed that several early telescope makers and user, such as Galileo, looked through their Dutch or Galilean telescopes the wrong way round and realised that it functioned as a microscope. Several people in Galileo’s circle in the Accademia dei Lincei used such Galilean microscopes and it was Giovanni Faber of the Lincei, who gave the instrument its name. The first use of a Keplerian telescope, with two convex lenses, is credited to Cornelis Drebbel in 1619. 

We then get an account of Leeuwenhoek’s discoveries culminating in his discovery of sperm. Agrawal writes:

Combined with the theory that all female animals have eggs, which also made its appearance in the mid-1670s…

This theory originated with William Harvey in his De Generatione, Ex ovo omnia – All things come from an egg, in 1651.

The rest of the chapter deals with the development of the microscope and its use in artificial insemination followed by a long section on the history of the history of the camera, both more or less acceptable. 

Of course, the series of historical errors in this chapters leads on to speculate if the history in the other chapters is accurate. Unlike this chapter the others are not my speciality but as far as I could ascertain they are historically acceptable. 

The book has neither foot nor endnotes. There are lists of the experts consulted for each chapter and also a separate extensive bibliography of sources for each. There is also a useful index. The book has occasional black and white illustrations many of which are had drawn, one assumes by the author. Despite my complaints about the chapter on the lens, I recommend Roma Agrawal’s book, which is despite the flaws mentioned above an excellent read. 

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^[1] Roma Agrawal, Nuts & Bolts: Seven Small Inventions That Changed the World (in a Big Way), Hodder & Stoughton, London, 2023.

Origins of the astrolabe

In a recent excellent video on Hypatia – Myths and History, Tim O’Neill  correctly pointed out that the claim that Hypatia created the astrolabe was rubbish, going on to claim that it had existed for at least five centuries before she lived. Tim’s second claim is in fact wrong but is just one of many commons claims about the ancient origins of the astrolabe. I have decided to give a brief sketch of what we actually know about the origins of this multipurpose astronomical instrument. 

NATIONAL MARITIME MUSEUM, GREENWICH
In 694 ah (1294–95 ce), Mahmud ibn Shawka al-Baghdadi produced this astrolabe.

It would surprise most people to discover that the earliest known treatise on the astrolabe was written by Theon of Alexandria (c. 335–c. 405 CE), Hypatia’s father. This work is no longer extant but the Suda, the tenth-century Byzantine encyclopaedia, mentions it. Both the treatise on the astrolabe by the Greek, Christian scholar John Philoponus (c.490–c. 570) and that of the Syriac scholar Severus Sebokht (575–667) draw heavily on the treatise of Theon. It is not known and cannot be ascertained whether Theon invented the plane astrolabe or was merely writing about an already existing instrument.

The earliest surviving reference to the plane astrolabe is in a letter from Synesius of Cyrene (c. 373–c. 414), the Greek bishop of Ptolemais describing how Hypatia taught him how to construct a silver plane astrolabe as a gift for an official. This is the origin of the myth that she invented the astrolabe.

The invention of the astrolabe has been variously attributed to Ptolemaeus (c. 100–c. 170), Hipparchus (c. 190–c. 120 BCE) and Apollonius of Perga (c. 240–c. 190 BCE) but there is absolutely no evidence to support any of these attributions. Hipparchus and Apollonius both probably used a dioptra attached to a protractor to measure angles, which can be regarded as a precursor to the astrolabe.

A dioptra (Greek: διόπτρα) is a classical astronomical and surveying instrument, dating from the 3rd century BC. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand. If fitted with protractors, it could be used to measure angles. (Wikipedia) 

The reverse face of a plane astrolabe is basically a dioptra mounted on a protractor

Reverse face of an astrolabe with alidade (dioptra) North African, 9th century AD, Planispheric Astrolabe Khalili Collection Source: Wikimedia Commons

but it is the front of the instrument that is the key element of the instrument.

This is a stereographic projection of the celestial hemisphere known as a planisphere.

The planisphere face of an astrolabe

The earliest known reference to the planisphere is a text by Ptolemaeus:

The Planisphaeium (Greek: Ἅπλωσις ἐπιφανείας σφαίρας, lit. ’Flattening of the sphere’) contains 16 propositions dealing with the projection of the celestial circles onto a plane. The text is lost in Greek (except for a fragment) and survives in Arabic and Latin only. (Wikipedia)

Once again people try to attribute the origin of the planisphere to Hipparchus but as with the astrolabe, there is absolutely no evidence to support this attribution. 

Based on his authorship of the Planisphaeium, some try to attribute the invention of the astrolabe to Ptolemaeus but in his Mathēmatikē Syntaxis (Greek: Μαθηματικὴ Σύνταξις, lit. ’Mathematical Systematic Treatise’), better known as the Almagest, he describes the instrument that he used for his observations and it was an armillary sphere, not an astrolabe.

Magnetic Variations – VII One author, two authors, three authors, more

William Gilbert’s De Magnete is a book that covers a wide range of information on all aspects of magnetism, loadstones, magnets, and the magnetic compasses. He was a high ranking physician living in London and doesn’t appear to have travelled anywhere else let along sailed anywhere on a ship. This raises the justified question; how did he acquire much of the knowledge that he presents to his readers? Did he write the book alone, or were there others involved in its production? 

We know that he borrowed liberally from the works of Petrus Peregrinus de Maricourt (fl. 1269), Robert Norman (dates unknown), and William Barlow (1544–1625) without really acknowledging those borrowings. We would say he plagiarised them, but what he did was common practice amongst scientific authors during the Renaissance. There were, however, other parts of the book that relied on mariner’s knowledge to which Gilbert almost certainly did not have access. He boasts of having acquired knowledge of the behaviour of the mariner’s compass over all on the globe from conversations with the circumnavigators, Francis Drake (c. 1540–1596) and Thomas Cavendish (1560–1592) but were there others? 

We know according to the reports that at least one and possibly two others actually contributed text to De Magnete. Following Gilberts death, two other magnetists claimed the right to be considered his true disciple, William Barlow (1544–1625), who I dealt with in an earlier episode, and Mark Ridley (1560–c. 1624), who as I noted in an earlier episode lived in Wingfield House with Gilbert and whom I will deal with in the next post. Their rivalry developed into a mudslinging match in various publications, which I will also deal with in the next post. In one of his ripostes to Barlow,  Mark Ridley wrote:

[Edward Wright] was a verie skilful and painefull man in the Mathematickes, a worthy reader of that Lecture of Navigation for the East-India Company … [T]his man took great paines in the correcting the printing of Doctor Gilberts booke, and was very conversant with him, and considering of that sixt booke [of De Magnete] which you [Barlow] no way beleeve, I asked him whether it was any way of his making or assistance, for that I knew him to be most perfect in Copernicus from his youth, and he denied that he gave any aide thereunto, I replied that the 12 chapter of the 4 Booke must needs be his, because of the table of the fixed Starres, so he confessed that he was the author of that chapter, and inquiring further whether he observed the Author [Gilbert] skillfull in Copernicus, he answered that he did not, then it was found that one Doctor Gissope [Joseph Jessop] was much esteemed by him, and lodged in his house whom he knew alwaies to be a great Scholler in the Mathematick, who was a long time entertained by Sir Charles Chandish, he was a great assistance in that matter as we judged, and I have seen whole sheetes of this mans own hand writing of Demonstrations to this purpose out of Copernicus, in a book of Philosophie copied out in another hand[.] 

All that I can find about Joseph Jessop, who, according to Ridley, instructed Gilbert in Copernican cosmology is that he was apparently a fellow London physician and an erstwhile fellow of King’s. 

In contrast to the elusive Dr Jessop, Edward Wright (1561–1615) is one of the most prominent figures in relevant circles in the last quarter of the sixteenth century and the first quarter of the seventeenth. A leading mathematical practitioner, not just in England but in the whole of Europe, particularly in the areas of cartography and navigation. He had solved the mathematical problem of how to construct the Mercator projection and published it in one of the most important English books on navigation, his Certaine Errors in Navigation in 1599. He had made Simon Stevin’s equally important De Havenvinding (1599) available to English mariners by translating it into English and publishing it as The Hauen-finding Art, or The VVay to Find any Hauen or Place at Sea, by the Latitude and Variation also in 1599. He was the designer of important mathematical instruments, an advisor on and teacher of navigation and cartography.

Cover of Wright’s Certaine Errors Source: Wikimedia Commons

Source

As well as this supposed anonymous contribution to Gilbert’s masterpiece he is also a named contributor as the author of a so-called laudatory address at the beginning of the book or to give it its full title:

To the most learned Mr. William Gilbert, the distinguished London physician and father of the magnetic philosophy : a laudatory address concerning these books on magnetism, by Edward Wright. 

Wright lays it on thick in his opening paragraph:

Should there be any one, most worthy sir, who shall disparage these books and researchers of yours, and who shall deem these studies trifling and in no wise sufficiently worthy of a man consecrated to the graver study of medicine, of a surety he will be esteemed no common simpleton. For that the uses of the loadstone are very considerable, yea admirable, is too well known even among men of the lowest class to call for many words from me at this time or for any commendation. In truth in my opinion, there is no subject-matter of higher importance or of greater utility to the human race upon which you could have brought your philosophical talents to bear. 

Having in a long passage of purple prose emphasised the importance of the invention of the compass for mariners, Wright initially concentrates on the topic of magnetic variation, seeming to believe in opposition to Gilbert that the use of variation to determine longitude is a real possibility. He then moves on to the topic of magnetic dip and the possibility that this seems to offer to determine latitude by inclement and overcast weather. Here his praise goes into overdrive:

Thus then, to bring our discourse back again to you, most  worthy and learned Mr. Gilbert (whom I gladly acknowledge as my master in this magnetic philosophy [my emphasis]), if these books of yours on the Loadstone contained nought save this one method of finding latitude from the magnetic dip, now first published by you, even so our British mariners as well as the French, the Dutch, the Dames, whenever they have to enter the British sea or the strait of Gibraltar from the Atlantic Ocean, will justly hold them worth no small sum of gold. 

With reference to the sentence in brackets that I have emphasised, it should be remembered that Wright is no humble mariner but a graduate of Cambridge University, who is a leading authority on all aspects of navigation and the magnetic compass, as well as a published author and translator, so high praise indeed. It should however be noted that the plan to determine latitude by magnetic dip propagated by Gilbert in his book and so highly praised here, by Wright, was never actually realised.

Wright goes on to address Gilbert’s theory of diurnal rotation and rehashes the standard physical argument in its favour, that it is more plausible to believe that the comparatively small sphere of the Earth rotates once every twenty-four hours than that the vastly larger sphere of the fixed stars does so. He considers the religious objection but finally comes down in favour of a geocentric model with diurnal rotation.

Towards the end of his laudatory address Wright references two other European experts:

Nor is there any doubt that those most learned men, Petrus Plantius (a most diligent student not so much of geography as of magnetic observations) and Simon Stevinius, a most eminent mathematician will be not a little rejoiced when first they set eyes on these your books and therein see their own 𝜆𝜄𝜇𝜈𝜀𝜐-𝜌𝜀𝜏𝜄𝜅ή𝜈 or method of finding ports so greatly and unexpectedly enlarged and developed; and of course they will, as far as the may be able, induce all navigators among their own countrymen to note the dip no less than the variation of the needle.

Petrus Plancius (1552–1622) was a Flemish astronomer, cartographer, and clergyman, who was an expert on safe maritime routes to India and the Spice Islands. He would go on to become one of the founders of the Dutch East India Company in 1602. He is famous for his celestial globes and in particular for training the navigator Pieter Dirkszoon Keyser (c. 1540–1596)to be one of the first to map the stars in the southern hemisphere. Simon Stevin is already known to us and Gilbert endorsed the scheme of Simon Stevin (1548–1620), put forward in his The Hauen-finding Art to provide tables of the correctly measured variation to compare with measured observations as an aid to navigation. It can be assumed that Wright as the translator of The Hauen-finding Art introduced Gilbert to Stevin’s work. 

Of interest is the following allusion:

Let your magnetic Philosophy, most learned Mr. Gilbert, go forth then under the best auspices­–that work held back not for nine years only, according to Horace’s Council, but for almost another nine…

Copernicus alludes to the same advice from Horace’s The Art of Poetry on the opening page of the preface to De Revolutionibus:

For he [Tiedemann Giese] repeatedly encouraged me and, sometimes adding reproaches, urgently requested me to publish this volume and finally permit it to appear after being buried among my papers and lying concealed not merely until the ninth year but by now the fourth period of nine years. 

Turning now to Book 4 Chapter 12 of De Magnete, which Ridley relates was authored by Wright we find a detailed technical section on the best way to determine magnetic variation, which I described in my post in this series on De Magnete so, The twelfth chapter of book four provides the best and most detailed description of how to determine variation published up till that time.

The chapter describes in great technical details the various ways of determining magnetic variation at sea and on land. It includes detailed instruction for the design and construction of special instruments for this task and  outlines the mathematics necessary to carry out the calculations. It includes Tycho Brahe’s value for the deviation of the Arctic pole-star from true north, 2 deg. 55 min. but gives 3 degrees as a good approximation. It also includes a list of the right ascension and declination of bright, brilliant stars not far from the equator for determining variation at night and the construction of an instrument to do so. It closes with instructions on how to construct an instrument for finding the ortive amplitude on the horizon. For those who don’t know, the ortive amplitude is defined thus:

The arc of the horizon between the true east or west point and the centre of the sun, or a star, at its rising or setting. At the rising, the amplitude is eastern or ortive. (Wiktionary)

Instrument for determining variation on land

Instrument for determining variation at sea at night

an instrument for finding the ortive amplitude on the horizon.

All the above is very much in Wright’s area of expertise rather than Gilbert’s, so the claim that he wrote this chapter is very plausible. This of course raises the question as to whether Wright was the author,  or co-author of, or advisor on other sections of the book of a similar technical nature. This question could probably only be answered if we could find Gilberts working notes, draft manuscript(s), or correspondence from when he was working on the book. Unfortunately, when he died he donated his library and one assumes his papers to the College of Physicians of which he was President. I say, unfortunately, because the College of Physicians and its entire library was lost in the Great Fire of London, so we will never know if Wright contributed more to De Magnete or not.

From τὰ φυσικά (ta physika) to physics – XVII

As I explained in episode XII of this series where I introduced the work of the ancient Greek engineers and their machines, the discipline mechanics derives its name from the study of machines.

Greek μηχανική mēkhanikḗ, lit. “of machines” and in antiquity it is literally the discipline of the so-called simple machines: lever, wheel and axel, pulley, balance, inclined plane, wedge, and screw. 

Just as some scholars during the ‘Abbāsid  Caliphate studies, absorbed, criticised, and developed the works of Aristotle and John Philoponus on motion, and those of Aristotle and Ptolemaeus on astronomy, so there were others who took up the translated works of the Greek engineers such as Hero of Alexandria and Philo of Byzantium, extending and improving their work on machines. The Islamic texts on machines have an emphasis on timekeeping and hydrostatics.

For the earliest Islamic book on machines, we turn once again to the translation power house, the Persian Banū Mūsā brothers  Abū Jaʿfar, Muḥammad ibn Mūsā ibn Shākir (before 803 – February 873); Abū al‐Qāsim, Aḥmad ibn Mūsā ibn Shākir (d. 9th century) and Al-Ḥasan ibn Mūsā ibn Shākir (d. 9th century), the sons of the astronomer and astrologer on the court of the ‘Abbāsid caliph al-Maʾmūn, Mūsā ibn Shākir. Amongst their approximately twenty books, of which only three survived, the most famous is Kitab al-Hiyal al Naficah (Book of Ingenious Devices), which draw on knowledge of the works of Hero and Philo but also on Persian, Chinese, and Indian sources but which goes well beyond anything achieved by their Greek predecessors.  

It contains designs for almost a hundred trick vessels and automata the effects of which, “were produces by a sophisticated, if empirical, use of the principles of hydrostatics, aerostatics, and mechanics. The components used included tanks, pipes, floats siphons, lever arms balanced on axles, taps with multiple borings, cone-valves , rack-and-pinion gears, and screw-and-pinion gears.”^[1]

A thirsty bull gets to drink. Courtesy of Library of Topkapi Palace Museum, Istanbul, manuscript A.3474, model 6.

How a thirsty bull gets to drink. From D. Hill, The Book of Ingenious Devices, model 6.

(Right) Lamp with a perpetual wick. Courtesy of Staatsbibliothek zu Berlin, Preußischer Kulturbesitz, arabischen Handschriften, manuscript 5562, model 96. (Left) Inner workings of a lamp with a perpetual wick. From D. Hill, The Book of Ingenious Devices, model 96.

In the ninth century the ‘Abbāsid caliph al-Mustaʿīn (c. 836 – 17 October 866) commissioned the philosopher, physician, mathematician, and astronomer Qusta ibn Luqa al-Ba’albakki (820–912) to translate Hero’s Mechanica, a text in which Hero explored the parallelograms of velocities, determined certain simple centres of gravity, analysed the intricate mechanical powers by which small forces are used to move large weights, discussed the problems of the two mean proportions, and estimated the forces of motion on an inclined plane, which has only survived in the Arabic translation. 

Ibn Khalaf al-Murādī

In al-Andalus in the eleventh century, the engineer Ibn Khalaf al-Murādī about whom we know almost nothing authored Kitāb al-asrār fī natā’ij al-afkār (The Book of Secrets in the Results of Ideas), which describes 31 models consisting of 15 clocks, 5 large mechanical toys (automata), 4 war machines, 2 machines for raising water from wells and one portable universal sundial.

When I looked at the science of engineering and saw that it had disappeared after its ancient heritage, that its masters have perished, and that their memories are now forgotten, I worked my wits and thoughts in secrecy about philosophical shapes and figures, which could move the mind, with effort, from nothingness to being and from idleness to motion. And I arranged these shapes one by one in drawings and explained them.

Al-Muradi, The Book of Secrets in the Results of Ideas

Page from The Book of Secrets in the Results of Ideas

Page from The Book of Secrets in the Results of Ideas

Page from The Book of Secrets in the Results of Ideas

The most spectacular of all the Islamicate text on machines and mechanics is the Kitab fi ma’rifat al-hiyal al-handasiya, (The Book of Knowledge of Ingenious Mechanical Devices) commissioned in Amid (modern day Diyarbakir in Turkey) in 1206 by the Artuqid ruler Nāṣir al-Dīn Maḥmūd (ruled 1201–1222) and created by the artisan, engineer artist and mathematician Badīʿ az-Zaman Abu l-ʿIzz ibn Ismāʿīl ibn ar-Razāz al-Jazarī (1136–after 1206).

All that we know about al-Jazarī comes from his book. He was born in 1136 in Upper Mesopotamia the son of the chief engineer at the Artuklu Palace, the residence of the Mardin branch of the Artuqids the vassal rulers of Upper Mesopotamia, a position he inherited from his father. Al-Jazarī was an artisan rather than a scholar, an engineer rather than an inventor. 

The book, which al-Jazarī wrote at the command of Nāsir al-Dīn, is divided into fifty chapters, grouped into six categories; I, water clocks and candle clocks (ten chapters); II, vessels and figures suitable for drinking sessions (ten chapters); III, pitchers and basins for phlebotomy and ritual washing (ten chapters); IV, fountains that change their shape and machines for the perpetual flute (ten chapters); V, machines for raising water (five chapters); and VI, miscellaneous (five chapters): a large ornamental door cast in brass and copper, a protractor, combination locks, a lock with bolts, and a small water clock. Donald R. Hill, DSB

A Candle Clock from a copy of al-Jazaris treatise on automata

Al-Jazari’s “peacock fountain” was a sophisticated hand washing device featuring humanoid automata which offer soap and towels.

His work was clearly derivative and he cites the  Banū Mūsā, the mathematician, astronomer, and astrolabe maker Abū Ḥāmid Aḥmad ibn Muḥammad al‐Ṣāghānī al‐Asṭurlābī (died, 990), Hibatullah ibn al-Husayn (d. 1139), and a Pseudo-Archimedes as sources. Many of his devices are improved models of ones described by Hero of Alexandria and Philo of Byzantium. He probably also drew on Indian and Chinese sources. 

The book is clearly written in straightforward Arabic; and the text is accompanied by 173 drawings, ranging from rudimentary sketches to full page paintings. On these drawings the individual parts are in many cases marked with the letters of the Arabic alphabet, to which al-Jazarī refers in his descriptions. The drawings are usually in partial perspective; but despite considerable artistic merit, they seem rather crude to modern eyes. They are, however, effective aids to understanding the text. Donald R. Hill, DSB

Diagram of a hydropowered perpetual flute from The Book of Knowledge of Ingenious Mechanical Devices by Al-Jazari in 1206.

The elephant clock was one of the most famous inventions of al-Jazari

The book was obviously fairly widespread in Islamicate culture judging by the number of surviving manuscripts but unlike the work of the Banū Mūsā it was first translated from the Arabic into a European language in modern times. 

Our last Islamic engineer is the Ottoman Turk polymath Taqi ad-Din Muhammad ibn Ma’ruf ash-Shami al-Asadi (1526–1585), who as we saw in the last episode designed, built, and managed the observatory in Istanbul for Sultan Murad III (1546–1595). Taqī al-Dīn is famous for his mechanical clocks about which he wrote two books. 

1. The Brightest Stars for the Construction of Mechanical Clocks (al–Kawākib al–durriyya fī waḍ ^ҁ al–bankāmāt al–dawriyya) was written by Taqī al-Dīn in 1559 and addressed mechanical-automatic clocks. This work is considered the first written work on mechanical-automatic clocks in the Islamic and Ottoman world. Taqī al-Dīn mentions that he benefited from using Samiz ‘Alī Pasha’s private library and his collection of European mechanical clocks.
2. al–Ṭuruq al–saniyya fī al–ālāt al–rūḥāniyya is a second book on mechanics by Taqī al-Dīn that emphasizes the geometrical-mechanical structure of clocks, which was a topic previously observed and studied by the Banū Mūsā and al-Jazarī.

Mechanical clock of Taqī al-Dīn. Image taken from Sifat ālāt rasadiya bi-naw’in ākhar.

He also wrote The Sublime Methods in Spiritual Devices (al-Turuq al-saniyya fi’1-alat al-ruhaniyya) a treatise in six chapters 1) clepsydras, 2) devices for lifting weights, 3) devices for raising water, 4) fountains and continually playing flutes and kettle-drums, 5) irrigation devices, 6) self-moving spit. 

Sixteenth-century Ottoman scientist and engineer Taqi al-Din harnessed surging river water in his designs for an advanced six-cylinder pump, publishing his ideas in a book called ‘The Sublime Methods of Spiritual Machine’. 
The pistons of the pump were similar to drop hammers, and they could have been used to either create wood pulp for paper or to beat long strips of metal in a single pass.

The self-moving spit in part six uses an early steam turbine as motive power:

“Part Six: Making a spit which carries meat over fire so that it will rotate by itself without the power of an animal. This was made by people in several ways, and one of these is to have at the end of the spit a wheel with vanes, and opposite the wheel place a hollow pitcher made of copper with a closed head and full of water. Let the nozzle of the pitcher be opposite the vanes of the wheel. Kindle fire under the pitcher and steam will issue from its nozzle in a restricted form and it will turn the vane wheel. When the pitcher becomes empty of water bring close to it cold water in a basin and let the nozzle of the pitcher dip into the cold water. The heat will cause all the water in the basin to be attracted into the pitcher and the [the steam] will start rotating the vane wheel again.” 

Naturally by Taqī al-Dīn’s time the Renaissance was in full swing in Europe and European artist-engineers were already writing their own books on machines and mechanics. 

As can be seen Islamic engineers knew of and built on the work of their Greek predecessors and the work of the Banū Mūsā and Ibn Khalaf al-Murādī became known in Europe exercising an influence on the European developments in machines and mechanics. There was also an information flow in the 16^th century between the observatory in Istanbul and Europe.

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^[1] E. R. Truitt, Medieval Robots: Mechanisms, Magic, Nature, and Art, University of Pennsylvania Press, 2015 p. 20 quoting Donald Hill, “Medieval Arabic Mechanical Technology,” in Proceedings of the First International Symposium for the History of Arabic Science, Aleppo, April 5–12 1976, Aleppo: Institute forb the History of Arabic Science, 1979.

Politicians (not) taking advice from experts in 19th-century Britain.

Roland Jackson is a historian of nineteenth-century science in Great Britain, who is the author of a highly praised biography of John Tyndall, The Ascent of John Tyndall: Victorian Scientist, Mountaineer, and Public Intellectual (OUP, 2018), which given the nature of some of Tyndall’s research work established Jackson as an expert on the early history of the very actual climate debate. He has, also, in this capacity published some very sensible work on the, somewhat heated, “did Tyndall steal from Eunice Newton Foote” discussion. Tyndall also features in Jackson’s newest book, albeit as just one of a cast of a multitude of expert voices, Scientific Advice to the Nineteenth-Century British State (University of Pittsburgh Press, 2023)^[1].

Jackson’s book is a vast repository of information, detailing the interactions between experts­–scientists, engineers, medical advisers­–and politicians over an extraordinary wide range of topic, seemingly from every aspect of human activity, in Great Britain throughout the nineteenth century, cooked down to a bare minimum to fit it into its slightly more than three-hundred pages. If expanded to its fullest extent, the information packed into those pages would, with certainty, fill a multi-volume encyclopaedia. However, despite its compactness, Jackson’s tome is not dry and indigestible, but well written, highly readable, informative, lucid, at times almost lyrical and it left this reader, at least, with a strong desire to discover more in greater depth about, what seems like, a thousand different topics. 

In the nineteenth century expert advisors interacted with and were consulted on a myriad of different topic by politicians, including health and safety in mines, factories, and explosive stores, public heath, the building of railways and the prevention of rail accidents, the prevention of marine disasters, the design of weapons, taxation, and much more. To handle all of these diverse topics in one continuous, chronological narrative would, I think, produce a highly complex and probably unreadable text, but Jackson approaches the task with a different strategy. 

His book is divided into seven section, six of which, excluding the first, deals with an area of public political policy and in which Jackson then deals with separate and interrelated topics chronological, showing how the handling of them by politicians and their expert advisors developed throughout the century, the main divisions are–(II) Empire and War, (III) Food, (IV) Infrastructure and Transport, (V) Industry, (VI) Social Condition and Public Health, (VII) Revenue and Standards.

As already pointed out his opening section (I) is different and deals with the Rise of Science. The books opening sentences state: 

Any starting point for a history of scientific advice to the British state will be arbitrary. The founding in 1660 of the Royal Society of London for the Improvement of Natural Knowledge, generally known as the Royal Society, is as good a place as any to begin. That is because this organization, surviving today as Britain’s elite scientific institution, had strong links to the state from the outset. 

This is followed by a brief sketch of the evolution of science in general and the Royal Society in particular during the eighteenth century leading up to the major sea change that the Royal Society underwent in the early part of the nineteenth century and the emergence of new scientific bodies such as the British Association, the Geological Society, the Astronomical society, the Institute of Civil Engineers, and others. The medical profession had professional societies with much older roots. Jackson goes deeper into both the Royal Society and the British Association. 

Having established the sources of many of the expert advisors, in particular the Royal Society, Jackson now takes us, topic for topic, through those areas where politicians called upon those advisors to dispense their wisdom to the political decision making machine, the British Parliament in Westminster. On each topic the reader gets introduced to a seemingly endless flood of committees and Royal commissions that were formed and in which selected advisors were called upon to add their opinions to the weight of the decision making process. 

What is made very obvious, particular in the first half of the century in how little influence those selected advisors had on any given issue in comparison to other political factors and how often inquiries petered out without any substantial legislation making it onto the books. It becomes very clear the parliamentarians, who themselves come almost exclusively to the upper echelons, practiced what would now be labelled a libertarian attitude to reform, propagating the view that problems such as health and safety or pollution would be regulated by the owners of the factories, railways, or whatever because it was in their own interest and didn’t need the interference of the state in their private affairs. This attitude being oft contrary to the advice given by the experts. Whilst reading, the term that kept popping up in my head was laissez faire but as Jackson did not use the term in his main text, I began to wonder if I was misinterpreting his narrative. However, in his excellent twenty-seven page Conclusion, of which more later, he uses laissez faire to describe exactly those attitudes where it had occurred to me.

It is interesting to follow how as the century advanced this laissez faire approach was gradually eroded, as it became more and more obvious that the various areas were anything but self-controlling and/or self-improving and that legislation based on the advice proffered by the experts in those committees and commissions was actually necessary. Sometimes, this recognition and the necessary implementation took a look time to finally come to fruition. Jackson drops the example of air pollution, a constant theme throughout the nineteenth century was only finally, really tackled with the Clean Air Act of 1956! Decimalisation of the British currency was discussed and recommended by the experts for much of the century, but was rejected by the politicians on the grounds that it would not be understood and thus rejected by the great unwashed, probably leading to public disturbances, it was finally introduced on 15 February 1971! Metrication was on the table from early on in the century when the need for a unified national system of weights and measures was under discussion but was initially rejected in favour of the Imperial System as being too French and too revolutionary. It continued to be discussed and recommended by the experts throughout the century but despite the 1897 Weights and Measures Act, which finally legalised the use of metric units for trade, it was first 1965 before Britain began metrication, although as Jackson points out they still have miles and the pint!

Some random thoughts on the political side from the vast convolute that Jackson presents. The major influence on policies by members of both the House of Commons and the House of Lords was due to personal vested interests; these launching, disrupting, blocking, or even killing of policy initiatives on a regular basis. The number of times that proposed legislations was stymied by a change of government. The constant back and forth between the government and local authorities over responsibility for areas such as sewage disposal and public health before late in the century central bodies with responsibility for the area were finally established. The highly active role of the Privy Council in the nineteenth century, then still a powerful political force, unlike today. 

On the other side, within a long list of expert advisors who served on committees, gave evidence to Royal commissions, gave advice on specific problems, and were consulted on a bewildering range of topics, a small number of names, some of them well known from the history of science keep cropping up again and again asked to apply their expertise to the latest problem under discussion. One gets the feeling that figures such as Michael Faraday, George Airy, John Tyndall and Lyon Playfair must have spent their entire time rushing from one advisory meeting to another, in between doing extensive scientific research into some relevant political question or another. One aspect that I personally found fascinating was the battles between medical experts who supported the different theories of the hypothesised general causes of ill health, this being a period when the real answers were not yet know, a strong reminder how recent the discovery of the real scientific causes of disease is. 

The aspect of the book that most impressed me whilst reading is how Jackson manages to juggle the streams of information that he delivers to his readers without sending their brains into overload, truly a master class in succinct formulation and delivery. I mentioned earlier that the information that he delivers is very compact and if expanded to its fullest extent, the information packed into those pages would, with certainty, fill a multi-volume encyclopaedia. Jackson did, in his original manuscript unpack and expand some examples of how the problems were approached and handled in a series of case studies. The publishers decided the book was too long and the case studies were sacrificed in the service of comparative brevity. However, these have been published separately under the title Case Studies in Scientific Advice to the Nineteenth-Century British State: A companion to Scientific Advice to the Nineteenth-Century British State (University of Pittsburgh Press, 2023), two-hundred pages of absolutely fascinating reading available in hardback and paperback at very reasonable prices (the main book is not cheap) and almost given away as a Kindle.  

The book closes with a twenty-eight page Conclusion: Constraints on Influence, which summarises the entire contents of the book brilliantly and in its entirety would make for a much better review than my feeble efforts. 

There are sadly no illustrations, but there are very extensive endnotes that largely refer to the impressive bibliography but also contain occasional supplementary information to specific points. As already stated the bibliography is very long and very impressive, in particular the very, very long list of Parliamentary Papers that Jackson consulted during his research. There is also a very comprehensive index.

This book is, in my opinion, destined to become a classic and an obligatory read for scholars of virtually all aspects of nineteenth-century British science, engineering, and medicine, as well as scholars of nineteenth-century British politics. It is a serious academic tome and not really designed for the casual reader, although the case studies could definitely appeal to a wider audience. However, I suspect that those scholars who do take up Jackson’s excellent tome will, like myself, find themselves going, now that is fascinating or really!, I must find out more about it. 

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^[1] Roland Jackson, Scientific Advice to the Nineteenth-Century British State, University of Pittsburgh Press, Pittsburgh Pa., 2023

Hubble telescope and Leeuwenhoek bollocks from NdGT

Back in May 2023, Renaissance Mathematicus friend, Michael Barton, expert for all things Darwinian, drew our attention to a new piece of history of science hot air from the HISTSCI_HULK’s least favourite windbag, Neil deGrasse Tyson. This time it’s a clip from one of his appearances on the podcast of Joe Rogan, a marriage made in heaven; they compete to see who can produce the biggest pile of bullshit in the shortest time. NdGT is this time pontificating about Galileo and the telescope.

A couple of weeks back, another Renaissance Mathematicus friend, David Hop, drew my attention once again to the same Rogan/Tyson interview, this time a longer section in which NdGT extemporises about the space telescope, Hubble, and Antoni Leeuwenhoek before he reaches the section I dissected back in May last year. As to be expected Motor-Mouth-Tyson spews out a non-stop stream of pure drivel, which truly demands the attention of the HIST_SCI HULK: 

NdGT: Why do you think the Hubble Telescope…the mirror issues notwithstanding, which were ultimately fixed when, it was first launched…Why was it so successful? Version of the Hubble telescope previously launched by the military, looking down. The model for that telescope had already been conceived and built and was operating. Then we said we want one of those OK but that’s not public that this is going on. The telescope gets designed has the benefit of previous versions of it having been used successfully but looking down. We look up, this the perennial two way street astronomy in the old days and in modern times astrophysics. 

One doesn’t need to be a fucking rocket scientist to recognise that a military spy satellite, looking down, is technically, optically, functionally, conceptionally different to a space telescope, looking up. But is there any truth in Tyson’s stream of verbal garbage? Now neither Hulky nor I are experts on the Hubble Telescope, it wasn’t built in the seventeenth century, but Wikipedia has good articles on the history of Hubble and on the history of military spy satellites too. Tyson could have taken the time to read them before opening his mouth. But what the hell, why ruin a good story with facts? Neil, “who cares about facts”, Tyson obviously didn’t bother. 

The Hubble Space Telescope as seen from the departing Space Shuttle Atlantis, flying STS-125, HST Servicing Mission 4. Source: Wikimedia Commons

To save you having to turn to Wikipedia, a brief synopsis. We start with the military as Motor-Mouth-Tyson thinks they started the ball rolling and NASA jumped on the bus having seen that it works. 

The United States Army Ballistic Missile Agency launched the first American satellite, Explorer I, for NASA’s Jet Propulsion Laboratory on January 31, 1958. The information sent back from its radiation detector led to the discovery of the Earth’s Van Allen radiation belts.

Wikipedia

Note the date!

The theoretical idea goes back a bit further:

Herman Potočnik explored the idea of using orbiting spacecraft for detailed peaceful and military observation of the ground in his 1928 book, The Problem of Space Travel. He described how the special conditions of space could be useful for scientific experiments. The book described geostationary satellites (first put forward by Konstantin Tsiolkovsky) and discussed communication between them and the ground using radio, but fell short of the idea of using satellites for mass broadcasting and as telecommunications relays.

Wikipedia

Note once again both civil and military!

Turning to space telescopes and Hubble: 

In 1923, Hermann Oberth—considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky—published Die Rakete zu den Planetenräumen (“The Rocket into Planetary Space”), which mentioned how a telescope could be propelled into Earth orbit by a rocket.

Wikipedia

So not exactly a recent idea! 

The history of the Hubble Space Telescope can be traced to 1946, to astronomer Lyman Spitzer’s paper “Astronomical advantages of an extra-terrestrial observatory.” 

Wikipedia

Note the date, twelve years before that first military launch of a satellite looking down!

Spitzer devoted much of his career to pushing for the development of a space telescope. In 1962, a report by the U.S. National Academy of Sciences recommended development of a space telescope as part of the space program, and in 1965, Spitzer was appointed as head of a committee given the task of defining scientific objectives for a large space telescope.

Wikipedia

Liman Spitzer Source: Wikimedia Commons

Also crucial was the work of Nancy Grace Roman, the “Mother of Hubble”. Well before it became an officialNASA approved, she became the program scientist, setting up the steering committee in charge of making astronomer needs feasible to implement and writing testimony to Congress throughout the 1970s to advocate continued funding of the telescope. Her work as project scientist helped set the standards for NASA’s operation of large scientific projects. 

Space-based astronomy had begun on a very small scale following World War II, as scientists made use of developments that had taken place in rocket technology. The first ultraviolet spectrum of the Sun was obtained in 1946, and NASA launched the Orbiting Solar Observatory (OSO) to obtain UV, X-ray, and gamma-ray spectra in 1962. An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel programme, and in 1966 NASA launched the first Orbiting Astronomical Observatory (OAO) mission. OAO-1’s battery failed after three days, terminating the mission. It was followed by Orbiting Astronomical Observatory 2(OAO-2), which carried out ultraviolet observations of stars and galaxies from its launch in 1968 until 1972, well beyond its original planned lifetime of one year.

Wikipedia

I could go on, but I think that is enough to show that the Hubble Space Telescope was definitively not a case of the civil space programme copying an idea from the military space programme and that Motor-Mouth-Tyson is, as per usual, spreading high grade bovine manure.

NdGT: The invention of the telescope [babble between Tyson and Rogan] Galileo perfects the telescope He learns that the telescope has just been invented in the Netherlands the Dutch were opticians, so they invented the telescope and the microscope within a couple of years of one another This transforms science.

The Dutch were opticians! So what? So were people all over Europe. Funnily enough the man credited with having invented the telescope, Hans Lipperhey, lived in Middelburg in the Netherlands but was actually a German. The invention of the telescope and/or microscope had nothing to do with nationality. 

Rogan: Why did they invent the eyeglass the reading glass?

NdGT: The reading glass was earlier than that, but I don’t know when, The real advance was putting two lenses in line with one another. Trivial in modern times but that was a huge conceptual leap and what you would accomplish [sic] and in so doing depending on how you curve them and how you grind the shape of those lenses you would get a microscope or a telescope. And we’re off to the races! 

It you are going to pontificate about the history of optics and the invention of the telescope and the microscope, you really should know when eyeglasses were invented, as one of the central questions, in that history, is why did it take so long from the invention of eyeglasses, around 1260, to the invention of the telescope in 1608?  The accepted thesis in answer to this question is contained in Rolf Willach’s magisterial Long Route to the Invention of the Telescope: A Life of Influence and Exile (American Philosophical Society, 2008). Willach argues convincingly that it was not putting two lenses in line with one another that led to the telescope, several people had done that without creating a telescope, but masking or stopping down the lens. The shape or form of a hand ground lens becomes more inaccurate the further one goes from the middle. These inaccuracies in the outer areas of the lens cause a distorted image, no problem in eyeglasses where one looks through the centre of the lens, but a major problem in the attempt to create a telescope. Lipperhey was probably the first to mask or stop down the lens so that only the central, correctly ground, portion of the lens gets used to create the image. 

I could write a whole book about Motor-Mouth-Tyson, “depending on how you curve them and how you grind the shape of those lenses you would get a microscope or a telescope.” Let’s just say an explanation it is somewhat wanting in more ways than one. 

NdGT: That’s basically the birth of modern science as we think of it and conduct it. Because you say to yourself, my senses I don’t trust them to be the full record of what’s going on in front of me. 

That the telescope and the microscope extended human perception and added new layers of empiricism to the study of nature is beyond discussion but to call it the birth of modern science is typical Motor-Mouth-Tyson hyperbole. 

NdGT: You pull out a microscope, oh my gosh, Leeuwenhoek , the microscope guy, he got a drop of pond water, puts it under his microscope, just to think to do this, it’s just water, why do you think that’s something interesting to do? He said, I wonder, he was curious and puts it under and sees little, what he described as animalcules happily aswimming.

Rogan: Animalcules!

NdGT: Animalcules, these are like the amoebas and paramecia. So, he writes to…he reports on this to the scientific authorities, and they don’t believe him. They say Van Leeuwenhoek, we think you might have had too much gin before you wrote this letter. Why would anyone believe this that there’s entire creatures, an entire universe of creatures thriving in a drop of pond water. And so, the way science works, one report does not make it true, you need verification. They sent people to the Netherlands to verify his results and there it was the birth of microscopy and then they look at everything. Cells you know, they need vocabulary to describe what you are seeing. 

Antoni van Leeuwenhoek Portrait by Jan Verkolje, after 1680 Source Wikimedia Commons

Leeuwenhoek now gets the Motor-Mouth-Tyson stir some half facts with a portion of liquid bovine manure and splatter the result over the listener treatment. Leeuwenhoek did not put his drop of pond water under his microscope because that is not how his single lens microscopes worked. Wait a minute didn’t our narrator just explain that to make a microscope you need to put two lenses in line with one another? If you are building a compound microscope you do indeed need at least two lenses and often more, but Leeuwenhoek is famous for the fact that he used single lens microscopes of his own special design.

A replica of a microscope by Van Leeuwenhoek Source: Wikimedia Commons

The small spherical lens is embedded in a metal plate and the specimen to be viewed in placed on the spike behind the lens and the whole apparatus is held up to the light. At the time Leeuwenhoek examined pond water with his microscope, microscopists were examining anything and everything with their microscopes, so nothing very special in this act. “He reports on this to the scientific authorities” sounds like something out of a dystopian novel by Kafka or Orwell. At the time he was corresponding with the Royal Society in London, basically, at the time, a private gentleman’s club for those interested in natural philosophy, who were publishing the results of Leeuwenhoek’s microscopic investigation in the Philosophical Transactions.

The letter with the animalcules, a term coined by Henry Oldenburg Secretary of the Royal Society, when translating from Leeuwenhoek’ original colloquial Dutch was sent in 1676 and was by no means his first letter. 

.. this was for me, among all the marvels that I have discovered in nature, the most marvellous, and I must say that, for me, up to now there has been no greater pleasure in my eye as these sights of so many thousands of living creatures in a small drop of water, moving through each other, each special creature having its special motion.

Leeuwenhoeks animalcules letter to Oldenburg

The prominent Dutch physician Reinier de Graaf made Oldenburg aware of Leeuwenhoek’s investigations in a letter from 1673:

That it may be the more evident to you that the humanities and science are not yet banished among us by the clash of arms, I am writing to tell you that a certain most ingenious person here, named Leewenhoek [sic], has devised microscopes which far surpass those which we have hitherto seen, manufactured by Eustacio Divini and others. The enclosed letter from him, wherein he describes certain things which he has observed more accurately than previous authors, will afford you a sample of his work: and if it please you, and you would test the skill of this most diligent man and give him encouragement, then pray send him a letter containing your suggestions, and proposing to him more difficult problems of the same kind.

Oldenburg followed de Graaf’s suggestion and from then on the Royal Society regularly published Leeuwenhoek’s letters with his latest investigations until his death in 1723. 

Motor-Mouth-Tyson’ comment, “They say Van Leeuwenhoek, we think you might have had too much gin before you wrote this letter” is a piss poor joke and has no place in an account of the history of science. Leeuwenhoek’s discovery of single cell organisms did indeed cause some consternation because the Royal Society’s  resident microscopists, Robert Hooke and Nehemiah Grew where initially unable to replicate his observations, their microscopes were not powerful enough. Later Hooke would succeed but in the meantime the Royal Society was justifiably sceptical. The situation was not improved by Leeuwenhoek’s refusal to explain his methods out of fear of being plagiarised. 

Tyson is quite correct that scientific results have to be verified, usually by replication. Galileo’s telescopic discoveries, which Tyson introduces in the part of the interview that I dissected last time, were also initially met with scepticism, particularly as people were unable to replicate them. Something Tyson doesn’t mention. They were only accepted after the Jesuit astronomers of the Collegio Romano had finally succeed in replicating them. 

The Royal Society did indeed send a delegation to control Leeuwenhoek’s results. This was not in anyway exceptional in the seventeenth century where personal testimony from reliable witnesses was a common form of verification. When the Royal Society doubted the accuracy of Johannes Hevelius’ astronomical observations, because he refused to use telescopic sights on his instruments, they sent Edmond Halley to Danzig to investigate the matter. The measuring of atmospheric pressure using a primitive barometer by Pascal’s brother in law, Florin Périer, was witnessed and confirmed by Minim Fathers from a local friary. Here we have an interesting aspect of personal witness verification, church officials, rather than natural philosophers, were regarded as the most reliable and trustworthy witnesses. The delegation that went to visit Leeuwenhoek to investigate his animalcules’ reports was led by Alexander Petrie, minister to the English Reformed Church in Delft; Benedict Haan, at that time Lutheran minister at Delft; and Henrik Cordes, then Lutheran minister at the Hague. The visit was for Leeuwenhoek a success and his observations were fully acknowledged by the Royal Society.

NdGT: … and there it was the birth of microscopy and then they look at everything. Cells you know, they need vocabulary to describe what you are seeing. 

As I pointed out in an earlier post this was not the birth of microscopy, although Leeuwenhoek took it to a new level. Marcello Malpighi (1628–1694), Jan Swammerdam (1637–1680), Robert Hooke (1635–1703, and Nehemiah Grew (1641–1712) were all prominent microscopist contemporaries of Leuwenhoek, who all started their investigations and also published some of their results before Leeuwenhoek began his investigations. The were also not to first and these scholars, particularly Robert Hooke, had already been looking at everything. Ironically, Motor-Mouth-Tyson’s example “cells” had already been discovered by Hooke. His Micrographia (1665) contains a microscopic image of the cells in cork. Hooke coined the term because he thought they looked like the monk’s cells in monasteries.

Robert Hooke’s microscopic image of cork displaying the cell structure Source: Wikimedia Commons

NdGT That was the journey down small then the journey went big, and Galileo perfects the telescope… 

This is where the section of the interview that we dissected back in May last year begins. Motor-Mouth-Tyson is slowly becoming the HISTSCI_HULKS favourite punch bag although the man is so dumb, it’s a bit like shooting fish in a barrel. On a serious note, NdGT is wildly successful all over the Internet and almost everything he spews forth, and there’s an awful lot fit, about the history of science is either highly inaccurate or simply false and unfortunately his adoring fans don’t know better. Equally unfortunate is the fact that he simply ignores the criticisms of those who know better.

From τὰ φυσικά (ta physika) to physics – XII

As I explained at the very beginning of this series the Greek concept ta physika was very different from what we envision when we hear the word physics today. In fact, this series is an attempt to sketch the path from the ta physika of Greek antiquity to the emergence of our modern physics in the Early Modern Period. We can find fragments of the roots of physics is various different areas of thought in antiquity and I have already looked at the philosophers, the mathematicians, the astronomers, ancient Greek optics, and statics. Today, I will turn my attention to the engineers, which means basically the first century BCE Roman architect, Vitruvius (c. 75–after c. 15 BCE)

A 1684 depiction of Vitruvius presenting De Architectura to Augustus. Source: Wikimedia Commons

and the first century CE Greek engineer and mathematician, Hero of Alexandria (fl. 60 CE).

Image of Hero of Alexandria from a 1688 German translation of Hero’s Pneumatics Source: Wikimedia Commons

Although there are other aspects to their work the principal reason for including them is their work on machines, as I pointed out in the last episode, mechanics comes from study of machines.  

Greek μηχανική mēkhanikḗ, lit. “of machines” and in antiquity it is literally the discipline of the so-called simple machines: lever, wheel and axel, pulley, balance, inclined plane, wedge, and screw. 

As I explained in my series on Renaissance Science the re-emergence of the works of Vitruvius and Hero in the Renaissance triggered a whole culture of artist engineers and of machine books, both of which played a significant role in the cross over between the theoretical book knowledge of the scholastics and the practical knowledge of the artisans or better said the dissolving of the boundary between them creating a meld between the two types of knowledge that would over the next two and a half centuries lead to the modern concept of knowledge or science. Whereas the early knowledge of machines consisted of how they function and how to construct them, the emerging modern physics explained why they work.

Both Vitruvius and Hero of Alexandria were building on a long tradition of machine-building, Ancient Greek engineers, most of whose work has not survived but who are referenced by later authors such as Vitruvius, Hero, and Pliny. We have the fourth century BCE military engineer Polyidus of Thessaly, who served under Philip II of Macedon (382–336) and his two students Diades of Pella and Charias, all three of whom are referenced by Vitruvius in his own section on siege engines in Book X of De architectura.

Polyidus of Thessaly is credited with the Helepolis siege tower, shown as model above Source: Wikimedia Commons

They are also included in a list of “those who have written about machines” in the preface to Book VII on Finishing:

…those who have written about machines like Diades, Archytas, Archimedes, Ctesibios, Nymphodoros, Philo of Byzantium, Diphilos, Democles, Charias, Polyidos, Pyrrhos, and Agesistratos. 

Taken from Vitruvius Ten Books on Architecture Ed. Ingrid D Rowland & Thomas Nobel Howe

Nymphodoros, Diphilos, and Democles are not otherwise known. Pyrrhos (318–272 BCE), King of Epirus, was a renowned military strategist, who wrote a thesis on siegecraft.

A marble bust of Pyrrhos from the Villa of the Papyri at the Roman site of Herculaneum, now in the National Archaeological Museum of Naples, Italy Source: Wikimedia Commons

I have a separate post on Archimedes (c. 287–c. 212 BCE), who is without doubt the most well-known engineer in antiquity. Archytas (c. 420–c. 355 BCE) was a mathematician associated with the Pythagoreans. He is thought to have been a pupil of the Pythagorean, Philolaus (c. 470–c. 385 BCE) and to have been the teacher of Eudoxus of Cnidus (c. 390–c. 340 BCE). Like many figures in antiquity much was written about him but none of his own writings have survived. He is credited with the creation of the concept of the quadrivium–arithmetic, geometry, music, astronomy–which became the basis of mathematical education first on the Latin schools and later the universities in the Middle Ages. Vitruvius’ Book X Chapters 13, 14, and 15 are almost identical to chapters on siegecraft from the Περὶ μηχανημάτων Perì mēchanēmátōn (On Machines) by Athenaeus Mechanicus (fl. mid-to-late 1^st century BCE) and the, no longer extant book, of Agesistratos (late 2^nd century BCE), about whom almost nothing in known, is thought to be the common source. 

This just leaves Ctesibios and Philo of Byzantium from Vitruvius’ list. Ctesibios (fl. 285–222 BCE) wrote extensively on compressed air, i.e. pneumatics, but none of his work survives. However, he is referenced by Athenaeus, Vitruvius, Pliny, Proclus, and Philo of Byzantium.

Hydraulic clock of Ctesibius, reconstruction at the Technological Museum of Thessaloniki Source: Wikimedia Commons

Philo of Byzantium (c. 280–c. 220 BCE), also known as Philo Mechanicus, only gets referenced by Vitruvius, Hero, and the mathematician Eutocius of Ascalon (c. 480s–c. 520s CE), who discussed his method for doubling a cube. Almost nothing is known about him, other than that he spent most of his life in Alexandria. He left only one known work is an encyclopaedic book on mechanics the Syntaxis (Μηχανική Σύνταξη, Mēkhanikḗ Sýntaxē). This only survives in fragments, but internal references allow us to recreate the titles of all nine sections:

•  Isagoge (Εἰσαγωγή, Eisagōgḗ) – Introduction (general mathematics)
• Mochlica (Μοχλικά, Mokhliká) – Leverage (mechanics)
• Limenopoeica (Λιμενοποιικά, Limenopoiiká) – Harbour Construction
• Belopoeica (Βελοποιικά, Belopoiiká) – Siege Engine Construction
• Pneumatica (Πνευματικά, Pneumatiká) – Pneumatics
• Automatopoeica (Αὐτοματοποιητικά, Automatopoiētiká) – Automatons (mechanical toys and diversions)
• Parasceuastica (Παρασκευαστικά, Paraskeuastiká) – Preparations (for sieges) 
• Poliorcetica (Πολιορκητικά, Poliorkētiká) – Siegecraft
• Peri Epistolon (Περὶ Ἐπιστολῶν, Perì Epistolō̂n) – On Letters (coding and hidden letters for military use)

Belopoeica, Parasceuastica, and Poliorcetica are extant in Greek, as are fragments of Isagoge and Automatopoeica. For a long time only the first sixteen chapters of Pneumatica were known in a Latin translation of an Arabic text but in the early twentieth century three new fuller Arabic manuscripts were found, one in the Bodleian and two in the library of the Hagia Sophia.

Philo of Byzantium. Pneumatica: Facsimile and Transcript of the Latin … 534, Bayerische Staatsbibliothek Munchen

As can be seen Vitruvius and Hero are part of a tradition of Greek mechanics that extends over more than five centuries but it is only with the two of them that we have complete books that were rediscovered, translated, and printed in the Early Modern Period, contributing significantly to the practical turn that was an important feature of the emergence of modern science.

Once again with Vitruvius, we have a figure from antiquity about whom we know very little. He seems to have worked in some capacity for Julius Caesar (100–44 BCE) and as a military engineer for Caesar’s grandnephew and adopted heir, Gaius Octavius (63 BCE–14 CE), later the Emperor Augustus. Upon retirement he came under the patronage of Augustus’ sister Octavia Minor (c. 66­–11 BCE). 

He is, of course, renowned as the author of De Architectura Libri Decem, (Ten Books on Architecture), which is actually a description not a title, signifying ten parchment scrolls on the subject of architecture. As with the Elements of Euclid, there is a discussion as to whether Vitruvius actually wrote all ten books or merely brought together and edited the contents produced by several authors. The ten books are:

• Book 1: First Principles and the Layout of Cities
• Book 2: Building Materials
• Book 3: Temples
• Book 4: Corinthian, Doric, and Tuscan Temples
• Book 5: Public Buildings
• Book 6: Private Buildings
• Book 7: Finishing
• Book 8: Water
• Book 9: Astronomy, Sundials and Clocks
• Book 10: Machines

Viewed from our standpoint a peculiar mixture of themes but in antiquity there existed no division between architecture and mechanical engineering. In fact, service as a military engineer, like Vitruvius, was one of the two available sources for architectural training. The other was an apprenticeship as a builder. Although this seems strange to us now, we should remember that Leon Battista Alberti (1404–1472), who wrote the first architectural treatise in the Renaissance, De re aedificatoria (On the Art of Building) based on Vitruvius, written between 1443 and 1452 but published in 1485 as the first printed book on architecture, was a mathematician, who considered mathematics as the foundation of the arts and the sciences.  Also following the Great Fire of London in 1666, the two architects who rebuilt London were Christopher Wren (1632–1723), astronomer, mathematician and physicist, and Robert Hooke (1635–1703), a polymath, who was predominantly a physicist Neither of them was a trained architect. 

Of the ten books, it is the last three that in the Early modern period had an influence on the emergence of physics. Book 8, which deals with the practical side of water supplies is in some respects a treatise on applied hydrostatics. 

All illustration from Vitruvius taken from Vitruvius Ten Books on Architecture Ed. Ingrid D Rowland & Thomas Nobel Howe, CUP, ppb. 2001 There are many more and I heartily recommend this book

Book 9 deals with time a central theme in physics and the water clocks that he describes also, like parts of Book 8, an application of hydrostatics, with the more complex ones also involving the construction of machines.

It is Book 10 he opens up the full panoply of mechanics, the construction of machines. We find pully systems, cranes for building sites, cranes for ships and harbours, methods for hauling large blocks, winches, water wheels, bucket chains, the water screw, water pumps, hydraulic organs, hodometers (a mileometer) on land and on water, and to close a wide range of military weapons and siege engines. All of these machines are on a theoretical level examples of applied physics and explaining how and why they worked in terms of forces was a natural consequence of the Renaissance machine culture that Vitruvius’s book helped to inspire.

Note the aeolipile in the middle of the second row under Pneumatic

Included amongst Vitruvius’ machines is the toy steam engine, the aeolipile, which is most commonly associated with Hero of Alexandria to whom we now turn.

Illustration accompanying Hero’s entry in Pneumatica, published in the first century AD. “No. 50. The Steam-Engine. PLACE a cauldron over a fire: a ball shall revolve on a pivot. A fire is lighted under a cauldron, A B, (fig. 50), containing water, and covered at the mouth by the lid C D; with this the bent tube E F G communicates, the extremity of the tube being fitted into a hollow ball, H K. Opposite to the extremity G place a pivot, L M, resting on the lid C D; and let the ball contain two bent pipes, communicating with it at the opposite extremities of a diameter, and bent in opposite directions, the bends being at right angles and across the lines F G, L M. As the cauldron gets hot it will be found that the steam, entering the ball through E F G, passes out through the bent tubes towards the lid, and causes the ball to revolve, as in the case of the dancing figures.” Source: Wikimedia Commons

Unlike Philo of Byzantium and Vitruvius, who each only wrote one book, Hero left us with several works and that is all that he left us. As one source put it, apart from his works we know nothing at all about him. The earliest mention of his works is by Pappus around 300 CE and he himself quotes Archimedes making c. 250 BCE another terminus. He has been dated from 150 BCE to 250 CE, but Otto Neugebauer demonstrated that a lunar eclipse that Hero describes, in his Dioptra, having observed took place in 62 CE, hence flourished c. 60 CE.

Hero was a mathematician and an engineer and based on his texts he is judged by historians to have been a practical man rather than a scholar, although some of his texts appear to be the lectures of a teacher. His work also shows him to have carried out much in the way of experiments. His surviving works are:

• Pneumatica (Πνευματικά), a description of machines working on air, steam or water pressure, including the hydraulis or water organ 
• Automata, a description of machines which enable wonders in banquets and possibly also theatrical contexts by mechanical or pneumatical means (e.g. automatic opening or closing of temple doors, statues that pour wine and milk, etc.) 
• Mechanica, preserved only in Arabic, written for architects, containing means to lift heavy objects
• Metrica, a description of how to calculate surfaces and volumes of diverse objects
• On the Dioptra, a collection of methods to measure lengths, a work in which the odimeter and the dioptra, an apparatus which resembles the theodolite, are described
• Belopoeica, a description of war machines 
• Catoptrica, about the progression of light, reflection, and the use of mirrors 

Automata by Hero of Alexandria (1589 edition) Source: Wikimedia Commons

Spiritali di Herone Alessandrino ridotti in lingua volgare da Alessandro Giorgi da Vrbino. – In Vrbino : appresso Bartholomeo, e Simone Ragusij fratelli, 1592. – [4], 82 c. : ill. ; 4º Source: Wikimedia Commons

Modern reconstruction of wind organ and wind wheel of Heron of Alexandria (1st century AD) according to W. Schmidt: Herons von Alexandria Druckwerke und Automatentheater, Greek and German, 1899 (Heronis Alexandrini opera I, Reprint 1971), p. 205, fig. 44; cf. introduction p. XXXIX Source: Wikimedia Commons

There are other works attributed to him, but the attributions are considered doubtful. As can be seen, apart from the Catoptics, which I dealt with separately in the episode on optics, his surviving work covers much of the same territory as the mechanical chapters of Vitruvius Like Vitruvius, Hero was a major influence on the evolution of the anti-scholastic scientific thought, when his texts became known in the Early Modern Period. 

Jim Bennett (1947–2023) authority par excellence on the history of scientific instrument.

It’s Sunday afternoon and I’m sitting at my computer writing a blog post for my Magnetic Variations series on Robert Norman, sixteenth-century instrument maker and discoverer of magnetic dip. As I usually do when I’m writing, I took a short break to survey my social media channels and to check my emails and discovered that the leading historian of scientific instruments, Jim Bennett, has just died. One of the sources that I’m using for my bog post is the Oxford Dictionary of National Biography article on Robert Norman, written by one J. A. Bennett.

You can’t really call yourself a historian of early modern science and/or technology without having read, studied, and internalized some of Jim Bennett’s output on the history of scientific instruments. In my case, probably the most important piece of his output that I read was his The Mechanics’ Philosophy and the Mechanical Philosophy (Hist. Sci., xxiv (1986), but there is so much more. 

I only had one very brief online encounter with Jim Bennet, but it left me glowing like an immature schoolboy. In 2020, good Renaissance Mathematicus friend, Becky Higgitt, organised a conference Science and the City, which was to be held in London and at which I was due to hold a lecture, How Renaissance Nürnberg became the Scientific Instrument Capital of Europe. Unfortunately, a pandemic by the name of Covid got in the way and the conference was transferred online. Speakers were requested to post there lectures online, mine is here, and the participants read them there, after which there was an extended online discussion about the paper with the author. I was both delighted and more than a bit awed when Jim Bennett entered the discussion on my lecture, both asking intelligent questions and offering further information. He was kind and generous with his comments about my humble efforts and left me with a very satisfied glow. 

The history of science and technology community yesterday lost another one of its true giants and all over the Internet historians of science and technology are mourning his departure. 

She sought it here, she sought it there, she found elusive longitude everywhere

In 1995, Dava Sobel, a relatively obscure science writer, published her latest book, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time^[1]. Sobel is a talented writer and she relates with great pathos the tale of the humble, working class carpenter turned clock maker, John Harrison, who struggled for decades against the upper echelons of the establishment and the prejudices of the evil Astronomer Royal, Nevil Maskelyne, to get recognition and just rewards for his brilliantly conceived and skilfully constructed maritime chronometers, which were the long sort after solution to the problem of determining longitude at sea. 

The book caught the popular imagination and became a runaway best seller, spawning a television series and a luxury picture book second edition. There is little doubt that it remains the biggest selling popular history of science book ever published. 

There is, however, a major problem with Ms Sobel’s magnum opus, never one to let such a thing as the facts get in the way of a good story her book is for large parts closer to a historical novel than a history of science book. In order to maintain her central narrative of good, John Harrison, versus evil, the Board of Longitude and Nevil Maskelyne, Sobel twists and mutates the actually historical facts beyond legitimate interpretation into a warped parody of the actual historical occurrences.  

From 2010 to 2015 the Maritime Museum in Greenwich and the Department for the History and Philosophy of Science at the University of Cambridge cooperated on a major research project into the history of the Board of Longitude under the leadership of Simon Schaffer for Cambridge and with Rebekah Higgitt and Richard Dunn as Co-investigators for Greenwich. The other participants were Alexi Baker, Katy Barrett, Eóin Phillips, Nicky Reeves, and Sophie Waring. This project produced a wonderful blog (archived here)^[2], workshops, conferences, and public events. As well as creating a digital achieve of the Board of Longitude papers, the project produced a more public finale with the major travelling exhibition in the Maritime Museum, Ships, Clocks & Stars: The Quest for Longitude, in 2014 to celebrate the 300^th anniversary of the Longitude Act. After Greenwich the exhibition was also presented in the Mystic Seaport Museum in Mystic, Connecticut, USA from 19 September 2015 to 28 March 2016, and the Australian Maritime Museum from 5 May 2016 to 30 October 2016. 

To accompany the exhibition a large format, richly illustrated book was published, not a catalogue, Finding Longitude: How ships, clocks and stars helped solve the longitude problem by Richard Dunn and Rebekah Higgitt.^[3] This volume, which I reviewed here, is wider reaching and much better researched than Sobel’s book and does much to correct the one-sided, warped account of the story that she presented. Unfortunately, it won’t be read by anything like the number who read Sobel.

In 2015 the project also delivered up the books Maskelyne: Astronomer Royal, edited by Rebekah Higgitt (The Crowood Press) and Navigational Enterprises in Europe and its Empires, 1730–1850 (Cambridge Imperial and Post-Colonial Studies) edited by Richard Dunn and Rebekah Higgitt (Palgrave Macmillan)

Now, the Board of Longitude research project has birthed a new publication, Katy Barrett’s Looking for Longitude: A Cultural History.^[4] This text, originally written as a doctoral thesis during her tenure as a researcher in the Board of Longitude research project has been reworked and published as the volume under review here. However, potential readers need have no fear that this assiduously researched, and exhaustively documented volume is a dry academic tome, only to be taken down from the library shelf for reference purposes. Barrett takes her readers on a vibrant and scintillating journey through the engravings, satires, novels, plays, poems, erotica, religion, politics, and much more of eighteenth-century London. 

Satire, plays, poems, erotica…? Isn’t this supposed to be a book about the history of the problem of determining longitude at sea and the solution that were eventually found to this problem? Regular readers of this blog will be aware of the fact that I’m a great supporter of the contextual history of science and technology. Historical developments in science and technology don’t take place in a vacuum but are imbedded in the social, cultural, and political context in which they took place. If you wish to truly understand those historical developments, then you have to understand that context. Katy Barrett has produced a master class in contextual history. 

From the very beginning, following the passing of the Longitude Act, the problem of determining longitude and the search for a solution to this problem because a major social theme and eighteenth-century London and the term longitude became, what we would now term, a buzzword and remained so for many decades. It is this historical phenomenon that Barrett’s truly excellent book investigates and illuminates in great detail. 

Barrett’s research covers a very wide range of topics with longitude turning up in all sorts of places and contexts. Following an introduction, What Was the Problem with Longitude, which sets out the territory to be explored and the reasons for doing so, the book is divided into three general sections, each divided into two chapters. 

The first section deals with visual aspects of the longitude story. Chapter one being centred on cartographical problems and presentations. Chapter two takes us into the world of visual presentations of instruments on paper. A practice with relation to proposed solutions for the longitude problem led eventually to accurate, technical visual presentations becoming standard in patent applications, as Barrett tells us. 

The second section views longitude as a mental problem with Chapter three showing how proposed solutions became viewed in the same way as other schemes proposed by the so-called projectors. Schemes designed to produce solutions to a wide range of intractable problems from the realms of finance, politics, religion etc. Here longitude acquired the dubious distinction of becoming compared to such perennial no-hopers as perpetual motion and the philosophers’ stone. Chapter four bears the provocative title Madness or Genius? And looks at the contemporary theories of madness and how they were applied to the proposers of solutions to the longitude problem in particular by the satirists. 

The third section introduces the social problem. Chapter five has the intriguing title Polite or Impolite Science? Polite science introduces us, amongst other things, to the fascinating eighteenth century genre in which men explain the new sciences to ladies, a topic that, of course, includes the longitude problem. We also have much on the elegant and informative presentation of instruments and their usage through engravings. Impolite science takes the reader into the fascinating world of scientific erotica, in which both latitude and longitude are frequently used as euphemisms. The sixth and final offering, A Cultural Instrument, continues the metaphorical use of navigation instruments both in erotica and beyond.

It is impossible within the framework of this review to even begin to present or assess the myriad of visual and verbal sources that Barrett examines, analyses, and presents to the reader, woven together in an ever-exhilarating romp through, it seems, all aspects of educated London society in the eighteenth century, illuminating ever more fascinating aspects of the widespread longitude discussion. 

Recurring themes that turn up again and again in the different sections of the book are the writings of the satirists, who made the eighteenth century a highpoint in the history of English literary satire, Swift, Arbuthnot, Pope, et al, the equally famous engravings of William Hogarth, and of course the struggles of carpenter turned clockmaker John Harrison, although here he is not presented as a lone hero but as just one of many struggling to present his ideas clearly to the Board of Longitude both visually in engravings and verbally in his writings. 

The book has eighty-four captivating illustrations in its scant two-hundred and fifty pages. Here I have to say I have my only complaint. The illustrations are grayscale reproductions of engravings and unfortunately quite a few of them are so dark that it is extremely difficult to make out the fine details about which Barrett writes in her astute analysis. 

The illustrations are listed and clearly described in an index at the front of the book. The seeming endless list of primary and secondary sources are included in a complete bibliography at the back, and the pages are full of footnote references to those sources. An index completes the academic apparatus. 

I could fill another couple of thousand words with wonderful quotes that Barrett delivers up by the barrow load for her readers, but I will restrict myself to just one riddle:

“Why is a Woman like a Mathematician?”

Surely a riddle to rival Lewis Carroll’s immortal “Why is a raven like a writing desk?”

I shall not reveal the answer, for that you will have to read Katy Barrett’s wonderful book.

As regular readers will know I do a history of astronomy tour of the Renaissance city of Nürnberg. One of the stations on that tour is Fembo House, now the home of the museum of the city of Nürnberg.

Fembo House

From 1730 to 1852, it was the seat of the cartographical publishing house Homännische Erben, that is “Homann’s Heirs” in English. In its time the biggest cartographical publishing house in Germany and probably the biggest in Europe. For six years from 1745, it was the workplace of Tobias Mayer (1723–1762), who was the astronomer-cartographer, who solved the problem of determining longitude by the Lunar Distance method.

Tobias Mayer

He did the work on this during his time in Nürnberg. I talk on my tour about Sobel’s Longitude, which most of my visitors have heard of and even often read and explain why it’s bad and I recommend that they read Dunn& Higgitt’s Finding Longitude instead. In future I shall add that when they have finished that, they should then read Katy Barrett’s Looking for Longitude: A Cultural History!

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^[1] Dava Sobel, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, Walker & Company, 1995

^[2] Click on Show Filters then and then find Quest for longitude under the Explore Themes menu – all there, 2010-2015. Thanks to Becky Higgitt for helping me find where Royal Museums Greenwich had hidden them!

^[3] Richard Dunn & Rebekah Higgitt, Finding Longitude: How ships, clocks and stars helped solve the longitude problem, Royal Museums Greenwich, Collins, London 2014

^[4] Katy Barrett, Looking for Longitude: A Cultural History, Liverpool University Press, Liverpool, 2022