Category Archives: Newton

April 8, 2026 · 7:57 am

From τὰ φυσικά (ta physika) to physics – LXIII

It would be no exaggeration to say that the publication of Newton’s Principia was like a tidal wave swamping the European scientific community in the closing stages of the seventeenth century. Newton’s theories would dominate the discourse in both mechanics and astronomy till at least the middle of the following century.

Godfrey Kneller portrait of Isaac Newton 1689 Source: Wikimedia Commons

In his biography of Newton, Richard Westfall wrote:

Nevertheless, nothing had prepared the world of natural philosophy for the Principia. The growing astonishment of Edmond Hally as he read successive versions of the work repeated itself innumerable times in single instalments. Almost from the moment of its publication, even those who refused to accept its central concept of action at a distance recognised the Principia as an epoch-making book. A turning point for Newton, who, after twenty years of abandoned investigations, had finally followed an undertaking to completion, the Principia also became a turning point for natural philosophy.^[1]

The advent of the book was not totally unexpected. Rumour had been ripe for much of 1687 and shortly before publication a long review appeared in the Philosophical Transactions of the Royal Society, who were after all the official publishers. The review was unsigned but it is known that Halley was the author. A fact that raises all sorts of ethical questions. The review, which summarises the Principia, begins:

The incomparable Author having at length been prevailed upon to appear in publick, has in this Treatise given a most notable instance of the extent of the powers of the Mind; and has at once shewn what are the Principles of Natural Philosophy, and so far derived from them their consequences, that he seems to have exhausted his Argument, and left little to be done by those who shall succeed him.^[2]

Newton’s own copy of his Principia, with hand-written corrections for the second edition
Source: Wikimedia Commons

The entire British mathematical community was eager to get its hands on a copy of this masterpiece and having done so rapidly discovered that it delivered an awful lot to chew on. John Locke (1632–1704), at the time of publication, a political refugee living on the European mainland, realised quickly that the mathematics was beyond him and so he asked Christiaan Huygens (1629–1695), whether the mathematics was sound. When Huygens answered in the affirmative, Locke proceeded to digest the propositions without the mathematical proofs.

Godfrey Kneller portrait of John Locke 1697 Source: Wikimedia Commons

Robert Hooke (1635–1703), who had loudly protested during the writing of the book that he should be acknowledged as the discoverer of the law of gravity, which almost drove Newton to abandon Book III, now seeing what he believed had been stolen from him protested even louder but simply got ignored.

Newtons book was greeted just as enthusiastically on the Continent as in Britain with lengthy reviews appearing in the spring and summer of 1688 in three of the leading journals: the Bibliothèque universelle in the Netherlands, the Journal des sçavans in France. And the Acta eruditorum in Germany.

The review in Bibliothèque universelle was purely a descriptive summary and was almost certainly written by John Locke. The Journal des sçavans stated that it presented “the most perfect mechanics that one can imagine” but fiercely rejected Newton’s physical concept–action at a distance. The Acta eruditorum devoted a total of eighteen pages to their review which warmly praised the book.

Halley had sent copies of the Principia to the leading natural philosophers on the Continent including Christiaan Huygens (1629–1695) and Gottfried Leibniz (1646–1716) both of whom were much impressed with Newton’s masterpiece but both of whom rejected the concept of action at a distance, Huygens called it absurd. However, he told his brother that he admired “the beautiful discoveries that I find in the work he sent me.”^[3]

Huygens paid his respects to Newton when he visited London in 1689. From then on until his death in 1695 his correspondence with Newton was dominated by topics related to the theories presented in the Principia. The same is true of the correspondence between Newton and Leibniz. Their strong interest in all aspects of the Principia, which dominated their correspondence demonstrated that with its publication Newton had advanced to the highest rank of European natural philosophers.

Portrait of Christiaan Huygens by Bernard Vaillant (1686) Source: Wikimedia Commons

In his letters Leibniz insisted that gravity must have a physical cause in the form of an aethereal vortex ala Descartes, a concept that Newton firmly rejected.

Portrait of Gottfried Leibniz by Andreas Scheits Source: Wikimedia Commons

However, Newton was himself not at all happy with the concept of action at a distance as he wrote in a letter to Richard Bently (1662–1742) in 1692

That one body may act upon another at a distance through a vacuum without the mediation of any thing else…is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking, can ever fall into it.

Newton played around with various concepts to account for gravity including a kind of aethereal explanation suggested by the Swiss mathematician, Nicolas Fatio de Duillier (1664–1753) and electricity. He finally adopted a kind of aethereal medium discussed in the Queries of the later editions of Opticks, which varies in density according to the matter of bodies located in it.^[4]

Newton’s search for a physical cause for gravity was tied up with his aim to revise or even rewrite the Principia. The process that he had gone through in the three years between De motu and Principia of constantly rewriting, expanding and improving his ideas didn’t cease with the publication of the Principia. The book had only just left the printer when Newton began revising and improving it. He had two copies of the book, one of which even had blank leaves interspersed between the printed pages, in which he began to note changes, improvements, additions for a second edition. Although, it would be 1713 before this planned second edition would appear, edited by Roger Coates (1685–1716) the first Plumian Professor of Astronomy at Cambridge University of whom Newton said, “If he had lived we would have known something.”

I’m not going to list and/or analyse the various technical changes that Newton made to the second edition but I will address the General Scholium added to the end of Book III where Newton addresses the problem of the physical cause of gravity and delivers up one of his most famous quotes. The General Scholium opens with another explanation from Newton as to why the vortex theory is not necessary to explain the workings of the cosmos. This is followed by a defence of the fact that God created the cosmos; Newton’s system had come under criticism for its supposed religious implication. However, it is what comes next that interests us here:

Thus far I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity. Indeed, this force arises from some cause that penetrates as far as the centres of the sun and planets without any diminution of its power to act, and that acts not in proportion to the quantity of the surfaces of the particles on which it acts (as mechanical causes are wont to do) but in proportion to the quantity of solid matter, and whose action is extended everywhere to immense distances, always decreasing as the squares of the distances. Gravity toward the sun is compounded to the gravities towards the individual particles of the sun, and at increasing distances from the sun decreases exactly as the squares of the distances as far out as the orbit of Saturn, as is manifest from the fact that the aphelia of the planets are at rest, and even as the far as the farthest aphelia of the comets, providing that those aphelia are at rest. I have not as yet been able to deduce from phenomena the reason for these properties, and I do not feign hypotheses [ my emphasis]. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental philosophy. In this experimental philosophy, propositions are deduced from the phenomena and are made general by induction. The impenetrability, mobility, and impetus of bodies, and the laws of motion and the law of gravity have been found by this method. And it is enough that gravity really exists and acts according to the laws that we have set forth and is sufficient to explain all the motions of the heavenly bodies and of our sea.

The emphasised phrase is, of course, the notorious Hypothese non fingo. What Newton is proposing here is a sort of provisional instrumentalism. He basically argues that I haven’t yet found the cause of gravity but it works mathematically so, I shall continue to accept and use it. He doesn’t exclude the possibility of eventually finding the cause. However, as is well known, or should be, a physical cause for Newton’s gravity has never been found and with time the successes of his theories led people to just ignore the fact that no cause had been found and to accept action at a distance as normal.

Another problem that readers of the Principia had was Newton’s mathematics. The widespread belief amongst those who have never read the book or even turned the pages is that Newton used analysis, of which he was, like Leibniz, one of those who produced a coherent system, to do his extensive mathematical work on motion. In fact, Newton had lost faith in the ability of analysis to provide undisputed mathematical proofs, so the whole Principia was composed and written in synthetic Euclidian geometry. However, traditional Euclidian geometry did not allow him to adequately model motion so, he devised a sort of analytical geometry, which he introduces as lemmas at the beginning of his work and then uses troughout the Principia. Even the leading mathematicians, such as Leibniz, had their problems with Newton’s innovations and both Leibniz and Jacob Hermann (1678–1733), a student of Jacob Bernoulli (1655–1705), translated Newton’s innovative geometry into Leibniz’s calculus.

Comets play a central role in Book III of the Principia the treatment of them taking up one third of the entire text. It was the demonstration that these apparently random visitors to the cosmos also obeyed Kepler’s laws of planetary motion and the law of gravity that sealed that claim that gravity was truly universal. Although, he had devoted so much time effort and space to the comets, Newton was still unsatisfied with his treatment of them. Following the publication of the Principia, he discussed this problem with Edmond Halley, who having already devoted time to the study of comets since the beginning of the 1680s offered to take on the task of further investigations. He did so, and the result of his investigations into the history of comet sighting led to his famous paper of 1705:

Portrait of Edmond Halley by Thomas Murray Source: Wikimedia Commons

Halley at first agreed with the longtime consensus that each comet was a different entity making a single visit to the Solar System. In 1705, he applied Newton’s method to 23 cometary apparitions that had occurred between 1337 and 1698. Halley noted that three of these, the comets of 1531, 1607, and 1682, had very similar orbital elements, and he was further able to account for the slight differences in their orbits in terms of gravitational perturbation by Jupiter and Saturn. Confident that these three apparitions had been three appearances of the same comet, he predicted that it would appear again in 1758–59

[…]

Halley’s predicted return date was later refined by a team of three French mathematicians: Alexis Clairaut (1713–1765),Joseph Lalande (1732–1807), and Nicole-Reine Lapaute (1723–1788), who predicted the date of the comet’s 1759 perihelion to within one month’s accuracy. (Wikipedia)

The successful prediction, based on Newton’s theories, of the return of what is now known as Comet Halley was a central factor in the victory of the Newtonian theories over the competing theories of the Cartesians. The other major victory concerned the debate over the shape of the Earth. Newton argued that the Earth was an oblate spheroid, flatted at the poles and bulging at the equator. Jean-Dominique Cassini and his son Jacques, both Cartesians, argued, based on measurements of a meridian, that the Earth was a prolate spheroid. Expeditions sent out by the French Academy of Science to Lapland and Peru to determine the length of one degree of longitude proved Newton right and the Cassini’s wrong. Both of these Newtonian victories in the middle of the eighteenth century led to a general acceptance that the cosmos was Newtonian.

As well these major scientific victories there was a second front working away to establish Newtonian mechanics against its Cartesian opponents that might be termed disciples spreading the Newtonian gospel. The Principia is for the normal human being impenetrable, a fact that is summed up by the, probably apocryphal, story about two students walking in Cambridge and spotting Newton on the street. “‘There goes a man,’ one of them said, ‘who writt a book that neither he nor anybody else understands.’” The following people made that impenetrable and the theories it contained accessible for a much wider range of people.

The first of those disciples were the Netherlander Willem ‘s Gravesande (1688–1742) and the French-born Englander John Theophilus Desagulier (1683–1744). ‘s Gravesande studied law at the University of Leiden whilst developing his interest in mathematics and astronomy, graduating with a doctorate in 1707. In 1715 he visited England with a Dutch delegation sent to welcome the Hanoverian succession in England. He met both George I and Isaac Newton and was elected a member of the Royal Society. In 1717, he was appointed professor of astronomy and mathematics in Leiden. In this position he began publicly to promote the Newtonian theories. In 1720, he published his Physices elementa mathematica, experimentis confirmata, sive introductio ad philosophiam Newtonianam (Mathematical Elements of Natural Philosophy, Confirmed by Experiments; or an Introduction to Newtonian Philosophy). In that book, he laid the foundations for the teaching of Newtonian mechanics through experimental demonstrations. He presented his work before audiences that included Voltaire, and Émilie du Châtelet. His book was highly influential well beyond the borders of the Netherlands.

Portrait of Willem ‘s Gravesande by Hendrik van Limborch Source: Wikimedia Commons

John Theophilus Desagulier was born in La Rochelle. However, his parents, Huguenot refugees moved to London in 1692. In 1705, he entered Christ Church College, Oxford graduating BA in 1709. He had attended lectures by John Keill (1671–1721) an inner circle Newtonian, who promoted Newtons work in lectures and experimental demonstrations. When Keill left Oxford in 1709, Desagulier continued his program of lectures and demonstrations, obtaining his MA in 1712. Having graduated he moved to London and began to offer public lectures in experimental philosophy, offering them in English, French and Latin. He was very successful holding over 140 courses of about 20 lectures per course on mechanics, hydrostatics, pneumatics, optics, and astronomy. In 1714, Newton had Desagulier appointed as demonstrator at the Royal Society, as successor to Francis Hauksbee (1660–1713). In this role he continued to support an experimental Newtonian science after Newton died and Hans Sloane (1660–1753) became president of the society. In 1720, the year it was published, Desagulier produced an English translation of ‘sGravesande, Willem, Mathematical Elements of Natural Philosophy Confirmed by Experiment, or an Introduction to Sir Isaac Newton’s Philosophy (London, 1720).

Portrait of John Desagulier after Hans Hysing Source: Wikimedia Commons

France was, of course, solidly Cartesian and on both sides not a little nationalism played a role in which system of science people supported. However, there was one small centre of Newtonism in Cirey-sur-Blaise the country seat of Gabrielle-Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (1706–1749), led by her lover François-Marie Arouet better known as Voltaire (1694–1778), writer, historian, philosopher, satirist. The two were actively supported in their Newtonism by the polymath Pierre Louis Moreau de Maupertuis (1698–1759), who led the expedition to Lapland to measure the length of a degree of arc of the meridian, which led to one of the major victories of Newton’s theories over those of Descartes, as already noted above. Also, by Alexis Clairaut (1713–1765) the mathematician and astronomer, who accompanied Maupertuis to Lapland and who played a central role in the recalculation of the return of Comet Halley, the other major victory of Newtonism.

Nicolas de Largillierre, portrait of Voltaire Source: Wikimedia Commons

Voltaire had spent the period from 1726 to 1729 exiled to England and in 1733 he published his Letters concerning the English Nation in English and in French the following year. The twenty-four letters were a wide-ranging account of various aspects of English culture, society and government. Four of them dealt with various aspects of Newton’s work:

Letter XIV: On Descartes and Sir Isaac Newton
Letter XV: On Attraction
Letter XVI: On Sir Isaac Newton’s Optics
Letter XVII: On Infinites in Geometry, and Sir Isaac Newton’s Chronology

In 1738, Voltaire published Éléments de la philosophie de Newton (Elements of the Philosophy of Newton) coauthored with Émilie du Châtelet, as noted above both had been introduced to Newton’s science by Willem ‘s Gravesande. This was an extensive, detailed exposition of Newton’s work written in simple language. A second edition in 1745, was prefaced by a section on Newton’s metaphysics which Voltaire had originally published separately in 1740. Historian of science, Charles Coulston Gillispie (1918–2015) wrote:

Voltaire explained Newtonian science to the educated public more successfully than any other writer, perhaps because he took more pains to understand it.

Émilie du Châtelet wrote and published her own original Institutions de physique (Lessons in Physics)(1st ed., 1740; 2nd ed., 1742) combining the work of both Newton and Leibniz. This was translated into both German and Italian. In 1749, she completed her translation with extensive commentary of Newton’s Principia into French. It was published in 1759.

Gabrielle Émilie Le Tonnelier de Breteuil, marquise du Châtelet (1706-1749) Source: Wikimedia Commons

In Italy Francesco Algarotti (1712–1764) published his Neutonianismo per le dame (Newtonism for Ladies) dedicated to Bernard Le Bovier de Fontenelle (1657–1757) in 1737 – a work consisting of information on astronomy, physics, mathematics, women and science and education, which despite the title was actually addressed to the general reader. This was translated into English in 1739 also into French and German.

Francesco Algarotti portrait by Jean-Étienne Liotard Source: Wikimedia Commons

Also in Italy, Europe’s first female university professor Laura Bassi (1711–1778) was one of the key figures in introducing Newton’s ideas of physics and natural philosophy to Italy.

Laura Bassi portrait by Carlo Vandi Source: Wikimedia Commons

Our final Newtonian disciple is the polymath Martin Folkes (1690–1754), the only man to hold both the presidency of the Royal Society and the Society of Antiquities, made it his life’s mission to promote the work of Newton.

Portrait of Martin Folkes by John Vanderbank Source: Wikimedia Commons

Folkes went on a grand tour of Europe between 1732 and 1735 preaching the gospel of Newton to learned societies and individual savants, in particular demonstrating those of Newton’s optical experiments that others had had difficulty replicating.

From Anna Marie Roos, *Martin Folkes (1690–1754)*: *Newtonian, Antiquary, Connoisseur*, OUP, Oxford, 2021

Thanks to the efforts of all of these people and other lesser lights by about 1750, Newtonian physics and astronomy had come to totally dominate Europe.

^[1] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, CUP, ppb. 1983, p. 469.

^[2] Westfall pp 469-470

^[3] Westfall p. 473

^[4] Isaac Newton The Principia, Mathematical Principles of Natural Philosophy, A New Translation by I. Bernard Cohen and Anne Whitman assisted by Julia Budenz, Preceded by A Guide to Newton’s Principia by I. Bernard Cohen p. 62

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Filed under History of Astronomy, History of Mathematics, History of Physics, Newton

March 26, 2026 · 7:26 am

From τὰ φυσικά (ta physika) to physics – LXII

When Newton had his exchange with Robert Hooke in 1679 concerning Hooke’s hypothesis on planetary motion it rewoke his interest in the topic, which he had dabbled in around 1664 and led to him constructing a quick demonstration that forces vary inversely as the square of the distance at the two apsides of an ellipse and then the same relation holds for every point on an ellipse. However, in typical style he showed this demonstration to nobody. Hooke’s visit didn’t provoke any further action on the topic.

However, when Edmond Halley visited him in 1684 asked, “what he thought the Curve would be that would be described by the Planets supposing the force of attraction towards the Sun to be reciprocal to the square of the distance from it.” and he replied, “it would be an Ellipse.” Halley responded by asking how he knew this and Newton said, “I have calculated it” almost certainly referring to the calculation from 1680. He didn’t give Halley the earlier calculation but instead sat down an wrote the nine page manuscript De motu corporum in gyrum ( On the Motion of Bodies in an Orbit) which:

Not only did it demonstrate that an elliptical orbit entails an inverse-squared force to one focus, but it also sketched a demonstration of the original problem: An inverse-square force entails a conic orbit, which is an ellipse for velocities below a certain limit. Starting from postulated principles of dynamics, the treatise demonstrated Kepler’s second and third laws as well. It hinted at a general science of dynamics of a projectile through a resisting medium.^[1]

Having brought this manuscript to the attention of the Royal Society, Halley was naturally eager to see it published but Newton insisted on improving his initial effort and set about doing so, a process on very intensive work that would take him well into 1686 and would end with the publication of the first edition of his Philosophiæ Naturalis Principia Mathematica (The Mathematical Principles of Natural Philosophy), which finally appeared in July 1687, a monumental work of several hundred pages that would fundamentally change the course of physics. This was not a straight expansion of the original nine page manuscript or the bringing together of preexisting material but the creation of completely new concepts in a process of increasing awareness of what was needed, and the writing of a work then abandoning it to start again not just once but several times. During the period from the autumn of 1684 until the spring of 1686, Newton abandoned all other activities in his life.

Newton started out by redrafting and expanding De motu. We know this because there are three surviving manuscripts of this work. One is the original that Halley took to the Royal Society and is archived there. The second is an exact copy of this made by Halley. The third manuscript is amongst Newton’s papers and is substantially different to the other two.

Like the original this starts with the definition of centripetal force which impels or attracts a body to some point regarded as a centre. So, the opposite of Huygens centrifugal force, which Newton acknowledges inspired the name that he chose for this new force. This is the first innovation that Newton brought into the discussion of motion and forces but was by no means the last.

We have become so used to Newton’s three laws of motion, which we get introduced to beginning in school physics lessons–although the modern versions that we get taught differ substantially from what’s presented in Principia–that we somehow think that they are obvious, natural or god given. However, if one follows Newton’s work in the 1680s one can see how he searched for and found them over various revisions. Following two definitions, the original De motu has four hypotheses of which the first would eventually become Newton’s first law, the principle of inertia. In his reworking of De motu, Newton demoted hypotheses three and four to lemmas, changed the name from hypothesis to law and added three new ones, making now a total of five laws. Only over time and various revisions did he whittle them done to the three laws for which he is famous.

As he worked, Newton became aware of two omissions from his original work the correction of which lays at the heart of the innovation presented in Principia. Up till Newtons time all of the theories of motion were what we now term kinematics, that is the study of motion without reference to mass or force. Newton turned kinematics into dynamics by introducing the concept of mass. As Wikipedia puts it: The fundamental principle of dynamics is linked to Newton’s second law. Which we now famously render as F= ma but in the original reads: A change in motion is proportional to the motive force impressed and takes place along the straight line in which the force is impressed. Mass, which Newton calls quantity of matter is defined in the very first definition in Principia: Quantity of matter is a measure that arises from its density and volume jointly.

As we all learned in school mass is constant whereas weight varies according to the force acting on the mass so, you have the same mass but weigh less on the Moon, with its lower gravity, than you do on Earth. It is thought that Newton was led to the necessity of a definition of mass by the experiments of Jean Richer (1630–1696), during his time in Cayenne, French Guiana (1671–1673), in which he determined, using a second pendulum, that the force of gravity on the equator differs from the force of gravity in Paris and consequently the weight of objects also varies.

Astronomical and gravimetric observations made on the island of Cayenne by Jean Richer, after an engraving by Sébastien Leclerc. Source: Wikimedia Commons

Newton’s other omission in the original manuscript of De motu is a complete lack of a concept of universal gravity. Over the months that he worked on his revision he began to examine the whole concept of attraction within the cosmos. To do so he asked the Astronomer Royal, John Flamsteed (1646–1719), for the observational data on the planets Jupiter and Saturn that were approaching a major conjunctions to determine how much they deviated from the ideal orbit predicted by Kepler’s laws due to mutual attraction, or perturbation. From Flamsteed he also acquired data on the great comet of 1680. Analysing the data, Newton now became convinced that all bodies attract each other with a force for which he continued to use the term gravity. For terrestrial motion he stopped using the term gravity and consistently used he own freshly coined term centripetal force.

Portrait of John Flamsteed by Thomas Gibson 1712

For his two innovations, Newton had turned to data from Richer and Flamsteed. This is an important aspect of the evolution of Principia out of the original De motu. Although he cut himself off from his everyday world to concentrate on his writing, he reached out by letter to Flamsteed and others to get data and other information that he required. In particular Edmond Halley became his errand boy, finding and supplying information that Newton would demand at regular intervals. Although Newton did most of the heavy lifting, Principia was anything but a solo effort.

Portrait of Edmond Halley by Thomas Murray c. 1690 Source: Wikimedia Commons

By November 1685, Newton had expanded the original nine page manuscript into two books with a total of around one hundred pages. This he named De motu corporum (On the Motion of Bodies). Book I frequently called Lectiones de motu (Lessons on Motion) covers his terrestrial dynamics and he actually submitted it to the university as his professorial lectures for 1684 and 1685. Book II dealt with celestial mechanics applying the physics developed in Book I to the cosmos. This was submitted as his professorial lectures in 1687 and published shortly after his death as De mundi systemate (The System of the World) in 1728. What we now have are the drafts of Books I and III of the Principia.

Newton went back to the grind stone and began revising and expanding the two books of this De motu corporum. Book I was developed into Book I and Book II was expanded into Book III of Principia. At the end of the original nine page De motu, Newton had included a brief section on motion in a resisting medium, a novum in the seventeenth century literature on motion. He now developed this giving the subject a full expansion and this became Book II of Principia.

As this final version began to take shape, Edmond Halley took on the role of editor and publisher on behalf of the Royal Society. Newton would send sections of the book to Halley, who would correct them then send them back to Newton. When they were both satisfied with the section, Halley would then take it to the printers, now correcting the galley proofs. As is well known, Halley also took on another responsibility. The Society had spent all the money available for book publications on De Historia Piscium (Of the History of Fishes) by Francis Willughby (1635-1672) and John Ray (1627–1705) in 1686, which failed to sell, leaving the Society unable to fund the publication of Principia. Halley ended up paying the cost of publication of Principia out of his own pocket.

Halley formally presented the finished first volume to Samual Pepys (1633–1703), the then president of the Royal Society, who gave his imprimatur on 30 June 1686, licensing the book for publication. The book finally appeared in summer 1687. Between November 1684 and the summer of 1687 Newton’s epoch-making work had grown through a series of transformations from a nine page manuscript into a five hundred page, three volume, printed and published book.

Newton’s masterpiece was intentionally anti-Cartesian. The prominent inclusion of mathematical as a qualifier for principles was a direct challenge to Descartes own Principia Philosophiae (Principles of Philosophy) from 1644 in which he outlined his own theory of the cosmos with its mechanical particle filled space and vortex theory. Book II of the Principia with its motion in a resistant medium, is the least read and least impactful part of Newton’s work but it closes with a proof that Descartes’ vortex theory doesn’t work.

It is important to note that there is a certain amount of irony attached to the fact that Principia was written for and published by the Royal Society. The Royal Society was solidly Baconian in its outlook. Natural philosophy should be utilitarian, developed for the good of mankind. There was nothing of this in the Principia a solidly abstract mathematical work. Bacon didn’t approve of mathematics either. Even worse, Bacon preached that natural philosophy should proceed inductively, the researcher collecting observed facts from which the hypothesis would eventually naturally emerge. Principia was instead strictly Aristotelian, a set of axioms from which the philosophy is developed deductively.

The initial reception of Newton’s monumental masterpiece was very mixed and very complex and will be the subject of the next episode in this series.

^[1] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, CUP, ppb. 1983, p. 404

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Filed under History of Astronomy, History of Physics, Newton

March 11, 2026 · 8:37 am

From τὰ φυσικά (ta physika) to physics – LXI

More than twenty years would pass between Newton’s awakening and his extraordinary period of learning in the mid 1660s and his finally putting pen to paper and writing the Principia. That period of his life is one that in popular history is full of myths and legends.

The whole period starts with a tangle of myths. There is a myth that Newton already had the concept of universal gravitation, the central element of his Principia, in the middle of the 1660s. Central elements of this are the apple story, both myth and legend, and the Annus mirabilis myth. I have dealt with the apple story in great detail here and am not going to repat myself. As I explained, also in great detail, the Annus mirabilis, in which it is claimed that in one year during the plague in 1665, the young Newton, he turned twenty-three in that year, basically discovered everything–calculus, optics, universal gravity–for which he later became famous. As I point out in my analysis this is total rubbish but the myth persists. In all of this, Newton himself is to blame because of claims that he made fifty years later:

In the beginning of the year 1665 … [claims about mathematics and optics]

And in the same year I began to think of gravity extending to y^e orb of the Moon ] (having found out how to estimate the force with w^ch [a] globe revolving within a sphere presses the surface of the sphere) from Keplers rule of the periodic times of the Planets being in sesquialterate proportion of their distances from the centre of their Orbs, I deduced that the forces w^ch keep the Planets in their Orbs must [be] reciprocally as the squares of the distances from the centres about w^chthe revolve: & thereby compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the earth, & found them answer pretty nearly.^[1]

In his Waste Book, a large notebook inherited from his stepfather, during this period Newton, inspired by Descartes, made three geometrical determination of circular motion none of which is of particular importance. Of interest is that at this time he didn’t accept the law of inertia. However, these determinations led on to his comparison of the “endeavour of the Moon to recede from the centre of Earth” with the force of gravity at the surface of the earth. He found that gravity if somewhat more that 4,000 times as great. He also substituted Kepler’s third law (that the cubes of the mean radii of the planets vary as the squares of the periods) into his formular for centrifugal force [taken from Huygens]: “the endeavours of receding from the Sun [he discovered] will be reciprocally as the squares as their distances from the Sun.” Here was the inverse-square relation resting squarely on Kepler’s third law and the mechanics of circular motion.^[2]

Newton’s elaboration, in old age, on what he had actually achieved in the 1660s was designed to silence his critics and to establish his priority for everything, at the time motivated by his dispute with Leibniz over the calculus. The comments on gravity were posthumously aimed at Robert Hooke (1635–1703) and Hooke’s claim that Newton had the concept of universal gravity from him. This goes back to an exchange from 1679, Newton in he meantime being occupied with teaching, mathematics, alchemy, and theology, having done nothing more on the question of gravity.

Following their bitter dispute over optics, Hooke having rudely dismissed Newton’s first paper from 1672, the two had had no contact. However, in 1679, Hooke now secretary of the Royal Society wrote to Newton to reestablish contact. He asked Newton if he was aware of his hypothesis on planetary motions as compounded of a tangential motion and “ an attractive motion towards the centrall body…”

Hooke was referring to a remarkable paragraph that had concluded his Attempt to prove the Motion of the Earth (1647, republished in 1679 in his Lectiones Cutlerianae). There he had mentioned a system of the world he intended to describe.

This depends upon three Suppositions. First, That all Coelestial Bodies whatsoever, have an attraction or gravitating power towards their own Centers, whereby they attract not only their own parts, and keep them from flying from them, as we may observe the earth to do, but that they also attract all other Coeletial Bodies that are within the sphere of their activity … The second supposition is this, That all bodies whatsoever that are put into a direct and simple motion, will so continue to move forward in a streight line, till they are by some other effectual powers deflected and bent into Motion. Describing a Circle, Ellipsis, or some other compounded Curve Line. The third supposition is, That these attractive powers are so much more powerful in operating, by much how much the nearer the body wrought upon is to their own Centers. Now what these several degrees are I have not yet experimentally verified …^[3]

Hooke is on the way to the concept of universal gravity but hasn’t arrived there yet. He is, however, obviously progressing past the concept that each planet has its own gravity, as expressed, for example, by Copernicus in De revolutionibus. His second supposition is obviously the principle of inertia and he correctly defines the dynamic elements of orbital motion. It is, however, important to note that whilst Hooke gives a good verbal account of his hypothesis on planetary motions he doesn’t provide a rigorous mathematical demonstration of it, and in fact never did. The difference between what Hooke achieved and what Newton would go on to do was summed up very neatly by Alexis Clairaut (1713–1765), after reviewing Hooke’s work, he wrote:

“what a distance there is between a truth that is glimpsed and a truth that is demonstrated”^[4]

On the basis of this letter Hooke later claimed that he had given Newton the concept of universal gravitation. Newton countered by saying that Hooke’s letter had merely returned his thoughts to a topic that he had already thought through earlier. The exchange between the two disputatious scholars continued on the subject of how an object would fall from a high tower if the earth was moving. Newton made a mistake in his analysis of the case, which Hooke corrected, surprisingly mildly, and the exchange petered out.

We now arrive at the legend that supposedly led to Newton putting pen to paper and writing the Principia. This is the infamous coffee house meeting in London between Hooke, Christopher Wren (1632–1723) and Edmond Halley (1656–1742) following a meeting of the Royal Society in January 1684. I’ve described this in detail in an earlier post but I will give a brief summary here. The question raised during the conversation is, given an inversed squared law of gravity would this lead to Kepler’s elliptical planetary orbits and his three laws. Wren offered a prize of a book worth forty shillings–that’s two pounds and one should remember that ten pounds p.a. was a labourer’s wage–to the first to provide a demonstration that this was indeed the case. Hooke claimed that he already had the solution but would only reveal it when the other two had failed to find one.

In August, Edmond Halley travelled to Cambridge and visited Newton in his chambers. Whether he had gone there to specifically put the question to Newton or he was there on other business and took the opportunity to do so, is not known.

According the Newton’s account as told to Abraham DeMoivre many years later, Halley asked Newton, “what he thought the Curve would be that would be described by the Planets supposing the force of attraction towards the Sun to be reciprocal to the square of the distance from it. Sir Isaac replied immediately that it would be an Ellipse…” Here was Newton claiming to know the answer to Wren’s question. Halley asked Newton how he knew it and he replied, “I have calculated it…”

Newton searched for this calculation but failed to find it but then promised Halley that he would send him the solution. Although Newton’s search seems like a charade, the claimed earlier solution really did exist:

Recently a copy of the demonstration has been identified. In it, began (as he later asserted) by demonstrating Kepler’s law of areas. Using the law of areas and accepting Hook’s definition of the dynamic elements of orbital motion, he showed first that the forces vary inversely as the square of the distance at the two apsides of an ellipse and then the same relation holds for every point on an ellipse. If the inverse-square relation initially flowed from the substitution of Kepler’s third law into the formula for centrifugal force under the simplifying assumption of circular orbits, the demonstration of its necessity in elliptical orbits far excelled in difficulty what had been a simple substitution. In fact, the demonstration, which probably dated from early 1680, was one of the two foundation stones on which the concept of universal gravity rested.^[5]

In November of 1684, Halley received his solution in the form of the nine page manuscript De motu corporum in gyrum ( On the Motion of Bodies in an Orbit) brought to him by Edward Paget, a young fellow of Trinity College.

Not only did it demonstrate that an elliptical orbit entails an inverse-squared force to one focus, but it also sketched a demonstration of the original problem: An inverse-square force entails a conic orbit, which is an ellipse for velocities below a certain limit. Starting from postulated principles of dynamics, the treatise demonstrated Kepler’s second and third laws as well. It hinted at a general science of dynamics of a projectile through a resisting medium.^[6]

Halley realised that he was in possession of a potential revolution in celestial mechanics. He immediately returned to Cambridge to talk to Newton about this treatise and on 10 December made a report to the Royal Society:

Mr. Halley gave an account, that he had lately seen Mr. Newton at Cambridge. Who had shewed him a curious treatise, De motu; which, upon Mr Halley’s desire, was, he said, promised to be sent to the Society to be entered upon their register.

Mr Halley was desired to put Mr. Newton in mind of his promise for the securing his invention to himself till such time as he could be at leisure to publish it. Mr. Paget was desired to join with Mr. Halley.^[7]

Newton now set about revising his manuscript for publication with the same intensity and single mindedness that he had devoted to the study of the modern mathematics and sciences in the period between 1664 and 1670. The revision took the best part of three years and the final product the three volumes of his Philosophiæ Naturalis Principia Mathematica (The Mathematical Principles of Natural Philosophy) finally appeared in July 1687.

Newton’s own copy of *Principia* with Newton’s hand-written corrections for the second edition, now housed in the Wren Library at Trinity College, Cambridge Source: Wikimedia Commons

^[1] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, CUP, ppb. 1983, p. 143

^[2] Westfall p. 152.

^[3] Westfall p. 382.

^[4] Quoted by W.W. Rouse Ball, An Essay on Newton’s Principia (Macmillan, 1893) p. 69 via Wikipedia

^[5] Westfall pp. 387-88

^[6] Westfall p. 404

^[7] Westfall p. 404

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January 28, 2026 · 8:40 am

From τὰ φυσικά (ta physika) to physics – LIX

Towards the end of the last episode of this series where I outlined the early life of Isaac Newton, I noted that between 1664 and the early 1670s, he undertook one of the most impressive period of self-study ever. That period I outlined in a post debunking the myth of the mythical Annus mirabilis. A large part of that time was devoted to the experimental study of light, in particular what Newton terms “the phenomenon of colour.” Before Newton it was in general believed that colour resulted through the changing of white light by external influences, becoming discoloured when passing through a prism or a lens, for example. His research showed, as we all know today, that white light itself is actually composed of a myriad of colours each of which has a different index of refraction, the spectrum being produced by white light being refracted. The rainbow is produced by sunlight being refracted by drop of rain water. These discoveries led to Newton’s first appearances in public as a natural philosopher. The first of which was a resounding success and the second boarding on a disaster.

Before addressing these we need to catch up with Newton’s progress with in the University of Cambridge. In 1669, Isaac Barrow (1630–1677) resigned as Lucasian Professor of Mathematics and recommended the then twenty-six year old Newton as his successor, a recommendation that was accepted by the college authorities and the young Isaac was duly installed.

Portrait of a young Isaac Barrow by Mary Beale (1633–1699) Source: Wikimedia Commons

This simple historical fact throws up several red flags. Firstly, by 1669 Newton had published absolutely nothing, he was a blank sheet but he gets appointed to a professorship? His extreme talent for mathematics had obviously become known to Barrow, who after all recommended him, as probably did others, and he seemed to be the best man for the job so, he was appointed. I once wrote a whole blog post titled, “Only 26 and already a professor” in which I analysed the seemingly extraordinary fact of a twenty six year old unknown being appointed to what is now regarded as the most prestigious chair for mathematics in the world.

In fact, in its early decades the Lucasian chair was anything but prestigious. Its raise to fame would first begin with Newton’s later career and then be extended by the long list of famous mathematicians and physicists who followed Newton as its occupants. In those early years it was in fact totally insignificant and on the basically still Aristotelian university it almost literally interested no one. This was why Barrow resigned; it didn’t appeal to his self-image. Very, very few students found their way to Newton’s lectures if at all and he oft lectured to an empty lecture hall cutting his lecture short and going back to his chambers. However, it did have a salary, meaning Newton was free to get on with his intensive research.

In the late 1660s Newton’s main area of activity was his research into optics and he now preceded to make an appearance outside the university walls on two levels, practical and theoretical.

His research had shown him that light was made up of a spectrum of colours each with a different index of refraction. This had major consequences for lenses and telescopes. The images in seventeenth-century telescopes was anything but sharp. They were fuzzy with coloured fringes. It was assumed that this was due to spherical aberration. A spherical lens does not focus all the rays passing through it at a single point but over a mall stretch, leading to a diffuse image. This had been first identified by Ibn al-Haytham (965–c. 1040) in his Kitāb al-Manāẓir, which had been translated in to Latin as De Aspectibus or Perspectiva and was very well known. The theorectical solution was also known. Lenses needed to be ground in other forms–parabolic, hyperbolic–however, people lacked the technical know how to achieve this. It was known that increasing the focal length of the objective lens reduced the spherical aberration leading to the spectacular aerial telescopes of Christiann Huygens (1629–1695) and Johannes Hevelius (1611–1687).

The 140ft telescope of Johannes Hevelius Source

Newton realised that lenses, which are basically prisms, also suffered from chromatic aberration and that this contributed much more to the diffuse image than the spherical aberration. Newton thought that it would be impossible to constuct a lens free of chromatic aberration, a major scientic error in his life, and so he set about construction a telescope that used a mirror to focus the incomming light rays instead of a lens, a reflector.

Newton was by no means the first to think of using a mirror in place of a lens to focus light rays. The reflector telescope has a history that begins with Hero of Alexandia (1st century CE?) as I have documented here. As Newton was still an undergraduate, the Scotish mathematician and astronomer James Gregory (1638–1675) had published a design for a reflecting telescope in his Optica promota (1663) but found the mirrors too difficult to construct. He then moved to London with the hope that London’s best lens-maker, Richard Reeve, could make his mirrors, but he was also unable to achieve the necessary quality to produce a usable image.

The isolated school boy, Isaac Newton had spent much of his time constructing things with his hands. During his time a grammar school in Grantham the stories say that he made furniture for the doll’s house of the step-daughter of Mr Clarke the apothecary in whose house he lodged. He also made a working model of a windmill which he mounted on the roof of the house. Now having decided that a reflector was the solution to chromatic aberration in telescopes, he set his manual talents to building one. He cast the mirror using an alloy of his own making consisting of copper, tin, and arsenic, which give the mirror a white surface colour, and devised a new method of grinding and polishing, using pitch, to polish the surface. He built the tube and the mounts. The telescope was only about six inches long but magnified nearly forty time in diameter, which made it more powerful that a six foot refractor. This was in 1668 and in 1671 he made a second one which at the urgings of Isaac Barrow he sent to the Royal Society in London, which immediately elected him a fellow in January 1672. The recluse, Isaac Newton, had arrived on the public stage.

It should be noted that although Newton had cracked the problem of producing a functioning reflecting telescope, it was found almost impossible to repeat his success. It was first fifty years later that the mathematician John Hadly (1682–1744) developed ways to make precision aspheric and parabolic objective mirrors for reflecting telescopes. Going on to manufacture both Newtonian and Gregorian telescopes.

In the same year Newton sent a letter to the Royal Society outlining his optical experiments with prisms and the conclusions he had drawn from them:

A Letter of Mr. Isaac Newton, Professor of the Mathematicks in the University of Cambridge; Containing His New Theory about Light and Colors: Sent by the Author to the Publishee from Cambridge, Febr. 6. 1671/72; In Order to be Communicated to the R. Society

If he had only expected praise for his scientific endeavours he must have been disappointed.

The two leading experts for things optical, at this time, were Robert Hooke (1635–1703) in London and Christian Huygens (1629–1695) in Paris, both of whom reacted very negatively to Newton’s paper. When asked for his opinion by Oldenburg, the secretary of the Royal Society, Huygens was at first lukewarm and did not appear to see anything new in Newton’s work, implying that he had not really read the paper, but, when pressed, rejected Newton’s theories out of hand. Newton was enraged and in his reply addressed Huygens, a leading figure in European natural philosophy, as if he were addressing a particularly ignorant schoolboy. Huygens said that if the discussion was to be conducted at that level, he would not contribute.

One of Newton’s major problems was that he had used his discoveries to support his own view that light was corpuscular in nature; he argued that the refracting medium imparted spin to a light particle (in the same way as a tennis player imparts spin to the ball, Descartes influence can clearly be seen here), and the different indexes of refraction are a result of the different degrees of spin imparted to the particles of each colour. Both Huygens and Hooke had developed wave theories of light, and it was Hooke who took up the attack. He interpreted Newton as saying that his theory of colour was dependent on a corpuscular theory of light. Yet, as he, Hooke, had already philosophically demonstrated that light was propagated in waves, then Newton’s theory must be wrong. This was just the main one of many criticisms that Hooke brought that led to a very tempestuous exchange of letters through Oldenburg over a period of several years.

At first Newton was content to answer, and he even showed that his theory worked equally well for a wave theory of light at the same time producing the best mathematical model for such a theory in the 17th century. A Serie’s of Quere’s Propounded by Mr. Isaac Newton, to be Determin’d by Experiments, Positively and Directly Concluding His New Theory of Light and Colours; and Here Recommended to the Industry of the Lovers of Experimental Philosophy, as they Were Generously Imparted to the Publisher in a Letter of the Said Mr. Newtons of July 8.1672 published in the Philosophical Transactions of the Royal Society.

During this period Newton worked on a long exhaustive essay on optics covering all of his research work up until this time, which he intended to publish in the Philosophical Transactions as a glorious rebuttal of all of his critics. However, Hooke did not let up, and Newton was further beset by criticisms from Ignace Gaston Pardies (1636–1673), a highly respected Jesuit scientist living in Paris who was also something of an expert for optics, and a second Jesuit, the Englishman Francis Hall (1595–1675), also known as Linus of Liège. The dispute with Pardies passed off relative quietly, but the one with Linus dragged on for six years and was continued by his student John Gasgoines after Linus’ death.

Although Linus was not a well-known philosopher, his objections are interesting and significant from a methodological point of view: he complained that he had been unable to repeat Newton’s experiments! This was not an isolated incident as the same thing occurred to Italian Newtonians at the beginning of the 18th century. In the case of the Italians, it turned out that the problem lay in the quality of the glass prisms that they were using and when they replaced them with better quality glass they were able to achieve the same results as Newton. One can assume that something similar happened in the case of Linus, but we will never know.

The results of this mass of criticism were fairly monumental. Newton’s patience, never very good at the best of times, gave out. He withdrew the extended optics essay that he had been writing and refused to have any more direct dealing with the Royal Society until 1704. He never established a relationship with Huygens. The feud with Hooke was patched up, only to break out again in the 1680s when Hooke accused Newton of having stolen the inverse square law of gravitation from him (but that, as they say, is another story). In fact, Newton’s first venture into publishing as such a disaster that he published nothing else until 1687, when he published his magnum opus Philosophiæ Naturalis Principia Mathematica ( The Mathematical Principles of Natural Philosophy)^[1].

In 1704, now that both Huygens and Hooke were finally dead, Newton published, in English, that “long exhaustive essay on optics covering all of his research work up until this time”, expanded into his Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light.

A Latin edition was published in 1706. Opticks is the most comprehensive volume on the topic published in the early modern period and it covers all then known areas of optics experimentally and mathematically. The opening sentence reads:

My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments.

This is a direct challenge to the Cartesians, of which Huygens was one, who expected philosophical explanations of optical phenomena. When he had published that original paper in 1672, one challenge from his critics was that he didn’t explain the nature of colour. Descartes as we saw believed that white light was homogeneous, that is monochrome, so, he had to explain the colours of the rainbow or the spectrum in general, as produced by a prism, for example. Experimenting with a prism Descartes produced the following argument. He stated that the particle of the second element, those that transmitted light, when refracted and rubbing against the particle of the third element, matter, acquired an uneven rotation which manifested itself as colours.

For Newton it was coloured light that was fundamental not white light and he considered that he had demonstrated this experimentally with his so-called Experimentum Crusis, Newton himself never used the term, (Book I, Part II, Theorem ii), Newton showed that the colour of light corresponded to its “degree of refrangibility” (angle of refraction), and that this angle cannot be changed by additional reflection or refraction or by passing the light through a coloured filter.

Folio 45v of Isaac Newton’s manuscript, New College MS 351/2, Oxford, which contains Newton’s diagram of the *experimentum crucis*, made at the request of Pierre Varignon for a French translation of the *Opticks*, 1722 (new.ox.ac.uk) Source Linda Hall Library

In his experiment he passed a beam of sunlight through a prism to produce a spectrum that he then masked so that only a single coloured ray, blue for example, progressed further. He passed this single ray of coloured light through a second prism and observed that although refracted again the ray didn’t change colour in any way. He concluded that the prisms were not added colour to the white light as it passed through, as had been previously believed.

Newton’s experimentum crucis . Within the darkroom a solar spectrum is projected onto the screen DE via the prism ABC and the aperture G in the screen DE . Only a monochromatic section of the spectrum passes through the small aperture in the screen, that is again deflected using a second prism abc but hardly undergoes any further spreading. In this way Newton showed that the colourless sunlight is made up of irreducible coloured light elements. The illustration is from Newton’s Opticks of 1704, but has been inverted here and has been reproduced with a retrospectively coloured spectrum. Source

Although it still had its critics Opticks became the standard work on optics during the eighteenth century only to be dethroned in the early nineteenth century, when Thomas Young (1773–1829), François Arago (1786-1853) , and Augustin-Jean Fresnel (1788–1827) produced a series of experiments that could not be explain by Newton’s corpuscular theory of light and replaced it with a wave theory.

As a small foot note, because of his theory of colour, Newton is considered one of those who provided the scientific explanation of the rainbow. We now teach schoolchildren that the rainbow has seven colures–red, orange, yellow, green, blue, indigo, violet–with lots of mnemonics to help them remember the correct order. Before Newton, people mostly thought that the rainbow had three, four or five colours and it was Newton who extended the list to seven. In his Opticks he wrote:

In the Experiments of the fourth Proposition of the first Part of this first Book, when I had separated the heterogeneous Rays from one another, the Spectrum pt formed by the separated Rays, did in the Progress from its End p, on which the most refrangible Rays fell, unto its other End t, on which the most refrangible Rays fell, appear tinged with this Series of Colours, violet, indigo, blue, green, yellow, orange, red, together with all their intermediate Degrees in a continual Succession perpetually varying . So that there appeared as many Degrees of Colours, as there were sorts of Rays differing in Refrangibility.

Newton, a closet Pythagorean, did so because there seven note on the diatonic scale.

^[1] The preceding six paragraphs are largely lifted from a post I wrote on the topic in 2008 on Will Thomas’ Ether Wave Propaganda blog.

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December 25, 2025 · 10:03 am

Christmas Trilogy 2025 Part 1: Pictures of Isaac

Humans are strongly guided by their visual perception. Naturally the other senses—smell, hearing, taste, touch—play a role but seeing is predominant. This is reflected in everyday speech. When we want to draw somebody’s attention to something or emphasise a point we often say “Look!” or “Look here!” even when we are only going to say rather than show something. We use the word “see” to signal understanding, “I see” or “do you see”.

Visual perception also played a strong role in the early evolution of science. People developed theories to try and explain what they could see. This was particularly true in astrology-astronomy where the only empirical evidence available was visual. It is significant that the period that most people believe is the nativity of modern science, the early seventeenth century, saw the invention of both the telescope and the microscope, the first instruments to extend the perception of one of the senses, namely vision, allowing researchers to see and examine things that were previously hidden from their sight.

Visual presentation plays an increasing role in the presentation of the history of science with historians examining and interpreting visual representation from times past. One thing that interests people, and not just historians, is what did a given scientist look like. Unfortunately, in popular presentations the portraits or photographs used tend to be those of said scientist as a dignified senior citizen, maybe when receiving that Nobel Prize or the tenth honorary doctorate, rather than as a young researcher when they were actually doing the work for which they were honoured. The further back we go the real difficulty is knowing whether the visual representation is real, i.e. true to life, or some artists ideal of the person in question.

Over the next three days I going to be taking a look at the surviving portraits of the three scholars, who make up my Christmas Trilogy every year—Isaac Newton, Charles Babbage, and Johannes Kepler.

Newton’s family were not by any means poor, when he inherited the family estates they provided him with an income of £600 p.a. at a time when the income of the Astronomer Royal was £100 p.a., but they were relatively simple puritan farmers so, there are no youthful portraits of Isaac, as a child. This, of course, all changed when he became the most famous natural philosopher and from the later part of his life we have quite a lot of portraits which documents his advancing age.

There is however one engraved portrait from 1677 on which the caption reads “Sir Isaac Newton. when Bachelor of Arts in Trinity College, Cambridge. Engraved by B. Reading from a Head painted by Sir Peter Lily in the Possession of the Right Honorable Lord Viscount Cremorne.”

Source: National Portrait Galery vis Wikimedia Commons

Sir Peter Lely was actually Pieter van der Faes, a Dutch portrait painter, who became a master of the Guild of St Luke, the city guild for painters, in Haarlem in 1637.

Peter Lely self-portrait c. 1660 Source: Wikimedia Commons

He moved to London in 1643 and succeeded Anthony van Dyck (1599–1641) as London’s most fashionable portrait painter going on to paint portraits of the rich, powerful, and famous including both Charles I and Oliver Cromwell, as well as Charles’ most famous mistress Nell Gwynne.

Peter Lely: long-time mistress of Charles II of England, Nell Gwynne as Venus, with her son, Charles Beauclerk, as Cupid.

Interestingly when Robert Hooke first came to London it was an apprentice to Lely but he then attended Westminster school instead.

Probably the most well-known portraits of Newton are those painted by Sir Godfrey Kneller (1646–1723). Kneller like Lely, whom he succeeded as London’s most fashionable portrait painter, was like him not English.

Godfrey Kneller self-portrait 1685 Source: Wikimedia Commons

He was born Gottfried Kniller in Lübeck the son of Zacharias Kniller a portrait painter. He first studied in Leiden but then became a pupil of Ferdinand Bol (1616–1680) a pupil of Rembrandt Harmenszoon van Rijn (1606–1669) and of Rembrandt himself. Together with his brother Johann Zacharias Kniller (1642–1702) he spent the early 1670s painting in Rome and Venice before the two moved to London in 1676 and Godfrey inherited Lely’s crown as the in portrait painter. Kneller set up a portrait studio and specialised almost exclusively in painting portraits. His production rate was almost unbelievable and he achieved it by a streamlined work process. At sittings he only made sketches of the face of the sitter and then filled in the rest without reference to the sitter. We don’t know if his Newton portraits were done in this manner.

Godfrey Kneller portrait of Isaac Newton 1702 Source: Wikimedia Commons

There are a series of four formal portraits of Newton in his eighties as the President of the Royal Society. These were painted by John Vanderbank (1694–1739), this time an English born painter but the son of the Huguenot refugee from Paris, John Vanderbank Snr. well-to-do proprietor of the Soho Tapestry Manufactory and Yeoman Arras-maker to the Great Wardrobe, supplying the royal family with tapestries from his premises in Great Queen Street, Covent Garden.

John Vanderbank self-portrait drawing c. 1720 Source: Wikimedia Commons

John Vanderbank studied composition and painting first under his father and then the painter Jonathan Richardson (1667–1745) before becoming a pupil of Godfrey Kneller in 1711 at his art academy in Great Queen Street, Covent Garden next door to his father’s tapestry workshop. Like Kneller, Vanderbank became a renowned portrait painter.

Vanderbank, John; Isaac Newton ,1725 Fellow, Source: Trinity College, Cambridge;

Vanderbank, John; Isaac Newton 1726; Source: The Royal Society

Vanderbank, John; Isaac Newton 1727, Source: Trinity College, Cambridge;

Vanderbank, John; Isaac Newton not dated; Source: The Royal Society;

There is a single, oft reproduced, portrait of Newton by the Irish painter Charles Jervas (c. 1675–1739) who was another pupil of and assistant to Godfrey Kneller and succeeded Kneller as Principle Painter in Ordinary to George I in 1723.

Self Portrait aged fifty, 1725 (oil on canvas) by Jervas, Charles (1675-1739)
oil on canvas

Newton portrait by Charles Jervas Source: Royal Society

John Smith (c. 1652–c. 1742), a very prolific English mezzotint engraver, was also a member of Godfrey Kneller’s circle and, as to be expected, he also produced an engraved portrait of Newton.

John Smith the Engraver 1696 painted by Sir Godfrey Kneller 1646-1723 Source: Tate Gallery

John Smith’s engraved portrait of Newton

Also from the Godfrey Kneller’s circle was the English engraver George Vertue (1684–1756), who produced an engraving of a Vanderbank portrait.

George Vertue, portrait by Jonathan Richardson (1733) Source: Wikimedia Commons

George Vertue’s portrait of Newton Source: Royal Society

There is a single portrait of Newton by Enoch Seeman the Younger (1689–1745), who was born in Gdańsk and was brought to London by his father Enoch Seeman the Elder, also a painter, in around 1704. He also painted in the style of Godfrey Kneller.

Self-portrait of Enoch Seeman Source: Wikimedia Commons

Enoch Seeman the Younger; Isaac Newton (1642-1727), Trinity College Cambridge

There is a portrait of Newton painted in 1712 by the English artist James Thornhill (1675/6–1734)

Purchased for the Newton family home of Woolsthorpe Manor. It is a rare depiction of the great man without a wig.

Woolsthorpe Manor portrait of Newton by James Thornhill

There is a second Thornhill portrait, also without wig, in Trinity College Cambridge

James Thornhill; Isaac Newton Trinity College, University of Cambridge;

Trinity College Cambridge, Newton’s college has a full sized marble statue of Newton produced by the French sculptor Louis-François Roubillac (1702–1762), who moved to London in 1730. This was presented to the college by the mathematician and Master of Trinity Robert Smith (1690–1768) in 1755 and cost £3000, a vast sum in those days.

Louis-François Roubillac marble statue of Isaac Newton, Trinity College Cambridge Source: Wikimedia Commons

Posthumously Newton rose to the status of a scientific god so, there are many engraved portrait from the later eighteenth and the nineteenth century often based on the Kneller portraits. Due to his fame and status, especially in later life, there are many portraits of Isaac Newton and I’m sure I’ve missed one or the other but the selection above should give you an impression of what England’s most famous scientist looked like.

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December 25, 2024 · 8:18 am

Christmas Trilogy 2024 Part 1: Isaac the alchemist

When Isaac Newton died on 20 March 1726 os. (31 March 1727 ns) he was the most feted natural philosopher and mathematician in Europe. Even his opponents amongst the Cartesians and Leibnizians, whilst rejecting his highly dubious action at a distance, were prepared to admit his mathematical genius.

Engraving of *Portrait of Newton* by John Vanderbank Source: Wikimedia Commons

He had written and published, what would be for the next century and a half, the definitive account of the theory of light with his Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light (English 1704, Latin Translation by Samuel Clarke (1675–1729) 1706), although his corpuscular theory of light was overthrown in the middle on the nineteenth century by the wave theory that had been propagated by Leibniz (1646-1716) and Hooke (1635–1703). His master work, truly a magnum opus, Philosophiæ Naturalis Principia Mathematica , first published in 1687 with a second revised edition in 1713, and a third, once again revised, edition in 1726, combined, in strict mathematical sentences, celestial and terrestrial mechanics creating a new astronomy and a new physics.

He was collator and systemiser, of the elements of calculus into a unified system, creating the most powerful mathematical tool available at the time, as was Leibniz. A situation that led to one of the most bitter priority and plagiarism disputes in the history of science. Although Newton lost faith in his own creation and did not use it to write his Principia.

By the time of his death, he had been president of the Royal Society of London for more than twenty years, ruling over it like an eastern potentate. Foreign tourists visiting London would attend meetings of the Royal Society just to witness the living legend, that was Newton, in the flesh. For thirty years he had also ruled over the Royal Mint with an iron fist, first as Warden in 1696 and then as Master from 1699 onwards. Regarded by previous Wardens as a sinecure, Newton took on the post as a hands on chief overseeing a major recoinage and generally taking a keen interests in all of the Mint’s activities. He was knighted in 1705 to increase his chances of wining a parliamentary election. It didn’t help he lost. Despite losing the vast sum of £20,000 ((£4.4 million in 2020) in the South Sea Bubble disaster, he died an extremely rich man.

Having become a national monument, he was given a state funeral and buried in Westminster Abbey along with the kings and queens of England. There is a spectacular monument to Newton in the Abbey in the nave against the choir screen. It was executed by the sculptor Michael Rysbrack (1694-1770) to the designs of the architect William Kent (1685-1748). It was finished in August 1730 and unveiled the following year. It has the following inscription:

The Newton Monument in Westminster Abbey

H. S. E. ISAACUS NEWTON Eques Auratus, / Qui, animi vi prope divinâ, / Planetarum Motus, Figuras, / Cometarum semitas, Oceanique Aestus. Suâ Mathesi facem praeferente / Primus demonstravit: / Radiorum Lucis dissimilitudines, / Colorumque inde nascentium proprietates, / Quas nemo antea vel suspicatus erat, pervestigavit. / Naturae, Antiquitatis, S. Scripturae, / Sedulus, sagax, fidus Interpres / Dei O. M. Majestatem Philosophiâ asseruit, / Evangelij Simplicitatem Moribus expressit. / Sibi gratulentur Mortales, / Tale tantumque exstitisse / HUMANI GENERIS DECUS. / NAT. XXV DEC. A.D. MDCXLII. OBIIT. XX. MAR. MDCCXXVI

This can be translated as follows:

Here is buried Isaac Newton, Knight, who by a strength of mind almost divine, and mathematical principles peculiarly his own, explored the course and figures of the planets, the paths of comets, the tides of the sea, the dissimilarities in rays of light, and, what no other scholar has previously imagined, the properties of the colours thus produced. Diligent, sagacious and faithful, in his expositions of nature, antiquity and the holy Scriptures, he vindicated by his philosophy the majesty of God mighty and good, and expressed the simplicity of the Gospel in his manners. Mortals rejoice that there has existed such and so great an ornament of the human race! He was born on 25th December 1642, and died on 20th March 1726.

The biggest surprise following Newton’s death was in the form of his nachlass. He had published comparatively little in his long life but it turned out that he had written vast amounts, which mostly never saw the light of day. To give some idea of the dimensions, for example, he published only two mathematical papers during his life, although he did pass round his unpublished mathematical manuscripts to his acolytes, who assembled at his feet in the coffee houses of London, the original Newtonians, usually after meetings of the Royal Society, so his work was known. The Mathematical Papers of Isaac Newton (1967 to 1981) edited by D. T. Whiteside (1932–2008) consists of eight large, thick volumes.

The real surprise was that there were far more ‘non-scientific’ papers than scientific ones. There were an estimated four million words on various theological topics, covering amongst other things Bible chronology, Biblical prophecies, the dimensions of the Temple of Solomon, and corruption of the Bible by the Catholic Church. Newton, who had maintained the public persona of a devout mainstream Anglican, was in fact a highly heterodox anti-trinitarian. He had toyed with the publication of a first theological text on Bible chronology but got cold feet, and in the end his The Chronology of Ancient Kingdoms Amended was first published posthumously in 1728.

Worse than this were the estimated one million words devoted to alchemy. It is now well known that Newton devoted at least thirty years of his life to the intensive study of alchemy. Beginning in about 1666 and continuing till he moved to London in 1696, Newton devoted a substantial amount of his time to reading, copying and annotating alchemy texts and conducting alchemical experiments. He even constructed a laboratory in his garden at Trinity college to carry out his experiments.

On the right of the gate to Trinity College is Newton’s Garden

After he moved to London he reduced the time and effort that he gave to the subject but didn’t stop altogether. It should be noted that during those thirty years, Newton carried out the experiments and wrote the texts that would later make up his Opticks, wrote most of the mathematical papers that went into those eight posthumous volumes, and composed, wrote and published the first edition of Principia.

With the ambition to become an adept, Newton kept his alchemical studies a secret and over the centuries the fact that the man, who many regard as the greatest scientist who ever lived devoted any time or effort at all to the study of something so unscientific as alchemy has caused commentators to shake their heads in disbelief. The combination of the arcane theological studies and the alchemy are a side to Newton that many of his admirers would prefer to see buried and forgotten. In fact, they trumpet loudly, one doesn’t need to know this stuff to understand his science and mathematics and recognise his genius. I prefer to think that to really get to grips with Newton you need to be open to all aspects of his life and work and not simply filter out the bits you like, whilst ignoring the rest.

In the following I shall sketch the reactions to and comprehension or oft incomprehension of Newton’s alchemical studies from the time of his death down to the present. This is inspired by the publication in 2019 of the first truly in depth study of all of Newton’s alchemical writings Newton the Alchemist: Science, Enigma, and the Quest for Nature’s “Secret Fire”^[1] by the leading historian of alchemy, William R. Newman. This is not a review of the book of which I have only read parts, but what follows comes mostly from it or from Newman’s essay A preliminary reassessment of Newton’s alchemy in The Cambridge Companion to Newton^[2].

Before looking at the reception of reactions to Newton the alchemist, one should mention that the vast majority of Newton’s papers disappeared from public scrutiny after his death only really emerging in the twentieth century. What happened to them is a long and complex story that I shan’t be dealing with here but if anyone is interested there is a very good account by Sarah Dry, The Newton Papers: The Strange & True Odyssey of Isaac Newton’s Manuscripts.^[3]

Before surveying the reactions to Newton’s alchemy, it pays to first examine the status of alchemy in the late seventeenth century and also to briefly sketch Newton’s commitment to it. The seventeenth and eighteenth century saw the gradual transition from alchemy to chemistry and it is during this period now referred to by the historians of the discipline as chymistry. In the late seventeenth century, when Newton was an active alchemist, alchemy, including transmutation, was still socially acceptable. In the latter part of his life, in the first third of the eighteenth century, Newton could have been aware of the that chrysopeia, (literally “gold making”) was heavily under attack from leading chymists, such as Georg Ernst Stahl (1659–1734) and Herman Boerhaave (1668–1738) and chemistry was beginning to emerge from its mother alchemy. In the late seventeenth century Newton was not the only major scientific figure of the period who was a practicing alchemist or chymist, other practitioners included Gottfried Leibniz (1646–1716), John Locke (1632–1704), and Robert Boyle (1627–1691). In fact, Boyle was one of Newton’s earliest and strongest influences on his alchemical studies.

Portrait of Robert Boyle by Johann Kerseboom, 1689 Source: Wikimedia Commons

On a side note, I find it intriguing that the alchemist that Newton most studied was not one of the great medieval alchemists but the contemporary alchemist George Starkey (1628–1665) writing under the pseudonym Eirenaeus Philalethes.

There should also be no doubt whatsoever that Newton was a fully committed alchemist, who donated much time and effort into investigations and experiments to discovery the philosopher’s stone. Investigations and experiments that were carried out with the same scientific rigour as his work in physics and astronomy.

The first reaction to the discovery of Newton’s alchemical writings came from his friend the antiquarian and physician William Stukeley (1687–1765), who “complied a draft biography of Newton after his friend’s death, he went so far as to suggest that Newton’s work in chymistry had the potential of freeing from the irrational belief in transmutation. Ironically, Newton the alchemist had been transmuted into Newton the Enlightenment chemist.”^[4]

Portrait of the English antiquarian William Stukeley attributed to Richard Collins Source: Wikimedia Commons

Following Newton’s death his alchemical writing were inherited by John Conduitt (1688–1737) and his wife, Newton’s niece and housekeeper, Catherine Conduitt née Barton (1679–1739). In turn they were inherited by their only child, Catherine (b. 1721), who married John Wallop, Viscount Lymington (1718–1749), the eldest son of the Earl of Portsmouth . Catherine’s son John Wallop (1742–1779) succeeded his grandfather to the peerage. In possession of the Portsmouth family, the papers literally disappeared into a trunk and were not mentioned again until 1855, when the physicist and inventor, David Brewster (1781–1868) wrote a biography or better said a hagiography of Newton, his “Memoirs of the Life, Writings and Discoveries of Sir Isaac Newton, a work which embodied the results of more than 20 years’ investigation of original manuscripts and other available sources.” (Wikipedia)

Brewster was totally unable to digest what he discovered in the Portsmouth papers. He was a staunch Presbyterian, even licenced as a minister, and he simply refused to believe that his hero Newton was a unitarian, which led to a vitriolic change of opinions on the topic with Augustus De Morgan (1806–1871), who was a unitarian. Even stronger was Brewster reaction to his discovery that Newton was an alchemist:

Newton’s biographer David Brewster marvelled at the fact that “a mind of such power, and so nobly occupied with the abstractions of geometry” could concern itself with the alchemical charlatanry “of a fool and a knave.”^[5]

Brewster expressed his amazement that Newton “could stoop to become even the copyist of the most contemptible alchemical poetry,” a fact that the Scottish scientist could only explain as the mental folly of a previous age.^[6]

For an excellent account of Brewster’s Newton hagiography and his dispute with De Morgan, I heartily recommend Rebekah Higgitt’s Recreating Newton,^[7] which I reviewed fourteen years ago!

Following Brewster indignant outburst, Newton’s alchemy once again disappeared into the mists until the Portsmouth Papers were auctioned by Sotheby’s on 13 and 14 July 1936. The economist John Maynard Keynes (1883–1946) bought a large number of the theological and alchemical manuscripts, and in a meantime almost legendary essay Newton the Man that was published posthumously in 1947 he wrote:

Newton was not the first of the age of reason. He was the last of the magicians, the last of the Babylonians and Sumerians, the last great mind which looked out on the visible and intellectual world with the same eyes as those who began to build out intellectual inheritance rather less than 10,000 years ago…He believed that by the same powers of his introspective imagination he would read the riddle of the Godhead, the riddle of the past and future events, divinely fore-ordained, the riddle of the elements and their constitution from the original undifferentiated first matter, the riddle of health and immortality.

In the same article, Keynes would add that Newton’s alchemical manuscripts were “wholly magical and wholly devoid of scientific value.”

[…]

Like Frazer, [Sir James Frazer in The Golden Bough] Keynes assimilated various “occult” pursuits such as alchemy and the quest for secret correspondences in nature under the same amorphous category, labelling them as magical. It is highly likely that Keynes had Frazer in the back of his mind when he unselfconsciously elided the borders between magic and alchemy, two disciples that Newton for the most part kept rigorously distinct.^[8]

Finally, in the late 1950s, Newton’s activities as an alchemist drew the attention of professional historians of science. A. Rupert Hall (1920–2009), who was editing Newton’s unpublished scientific papers and who would go on to become the first professor for the history of science in England, and his later wife, Maria Boas (1919–2009), the historian of Renaissance science, published a paper in 1958, Newton’s Chemical Experiments, (Archives internationales d’histoire des sciences, 11 pp. 113–53). The two were apparently unable to conceive that the great Newton would indulge in something as fraudulent as alchemy and asserted:

“Alchemy was never disinterested chemical research” and the adopted the goal of showing that “there is no evidence that any of <Newton’s> processes are of the kind necessarily preliminary to the Great Work, or that he ever hoped to fabricate a factitious gold.” These assertions are clearly belied by the obvious alchemical character of Newton’s “Of Natures obvious laws & processes in vegetation.” A text that the Halls seem not to have known in 1958. More than this, the Halls’ interpretation is challenged even by Newton’s experimental notebooks [which they had studied].^[9]

In 1971, the great Newton biographer, Richard S. Westfall (1924–1996) in his book Force in Newton’s Physics (Macdonald and Company):

… explicitly linked gravitational force to alchemy and what he called “the hermetic tradition,” a locution that clearly betrays the influence of Frances Yate’s 1964 Giordano Bruno and the Hermetic Tradition. Westfall developed this idea further in an article of 1972. [ “Newton and the Hermetic Tradition,” In A. G. Debus, Science, Medicine and Society in the Renaissance (New York: Science History Publications, 1972), vol. 2, pp. 183–98]. there he argued that Newton’s concept of force at a distance “derived initially from the world of terrestrial phenomena, especially chemical reactions.” In fact, Westfall even went so far as to claim that Newton’s concept of gravitational attraction emerged only after “he applied his chemical idea of attraction to the cosmos.”^[10]

Betty Jo Teeter Dobbs (1930–1994) took up and expanded Westfall’s thesis that Newton’s action at a distance came from his alchemical investigations in the first ever book-length. historical study of Newton’s alchemy The Foundations of Newton’s Alchemy, or the Hunting of the Greene Lyon, CUP, 1975). When it was published the book caused a minor sensation. After Dobbs’ investigations there could be no doubt that Isaac was a full blood alchemist with everything that it entailed.

On a personal note, I’m old enough that when I first got heavily involved in the history of science the so-called occult sciences–alchemy, astrology, natural magic– were tabu, not something a respectable historian should dirty their hands with. For me Dobbs’ book was a revelation, it convinced me that the occult sciences were definitely something that a historian of science should investigate.

Whilst acknowledging Dobbs’ important role in opening the can of worms that was Newton’s alchemy, amongst other things she researched and decoded the alchemical Decknamen, the mystical terms, such as Hunting of the Greene Lyon, behind which alchemist hid their reagents and experiment, Newman says that there is very little evidence in Newton’s writings to support the Westfall/Dobbs thesis that action at a distance was taken from alchemy.

In a second book The Janus Faces of Genius: The Role of Alchemy in Newton’s Thought (CUP; 1991) Doobs advanced the thesis that Newton’s interest in alchemy was integral to his unorthodox religiosity.

This thesis had already been aired by Mary S. Churchill in her 1967 paper The Seven Chapters, with Explanatory Notes (Chymia Vol. 12, 27–57).

In alchemical writings, Newton must have believed, lay hidden a religious expression stripped of sacerdotal dogmas, which was very close to his own belief. To him the Roman Catholic Church had usurped authority. It had abused and degraded Christianity by its drive for power, its use of confession, absolution, and indulgences, and by the corruption of the clergy. To him the alchemists must have represented the true unsullied wisdom of the past. They were the preservers of the teachings of the ancient wise men and of the earliest Christian Church. They kept in its true form the secret of salvation, regeneration and immortality, a mater of individual growth and conscience, not to be legislated by popes or bishops. (Churchill p. 38)^[11]

Newman says that “Churchill used the idea of the analytical psychologist Cark Jung that the “religious elements in alchemy quite outweigh its technical aspects.” ^[12]

Newman says of the religious thesis of Churchill and Dobbs that since the majority of Newton’s theological and religious writings have been digitalised it is possible to make a text analysis and comparison and there in no indication of a deep link between his theological and alchemistic writings.

The last decades have seen a growth on the number of high quality historians of alchemy who have devoted much energy to researching and analysis the alchemical literature, amongst others Bruce Moran, Tara Nummedal, Lawrence Principe, Jenny Rampling, and of course William Newman himself, who have raised the study of alchemy to a new academic level. As general introductions to the history of alchemy I recommend William R. Newman & Lawrence M. Principe, Alchemy Tried by Fire, (University of Chicago Press, 2002)

and Lawrence M. Principe The Secrets of Alchemy (University of Chicago Press, 2013).

Newman’s Newton the Alchemist: Science, Enigma, and the Quest for Nature’s “Secret Fire” is one of the most recent in depth studies to emerge as a result of this wave of scholarship.

Having dismissed the theories that Newton’s concept of action at a distance, and hence his theory of gravity, was tied up with his alchemy and that his alchemy was part of his theological heterodoxy, Newman telly us that in fact his study of alchemy influenced his thoughts on optics. Following Newman, Newton drew parallels between Boyle’s “redintegration” of saltpetre or niter, modern potassium nitrate, (described in his Certain Physiological Essays, 1661) where “redintegration refers to resynthesis after analysis – the dissolution of saltpetre into its ingredients and the subsequent recombination of those ingredients to arrive once more at saltpetre^[13]– and his own optical experiment where he used a prism to split white light into the coloured spectrum and recombined the colours into white light.

Newman also tells us that that as a result of his alchemical studies Newton developed a “theory of everything” that would explain organic life, the origin of heat and flame, the mechanical causes of gravitation, cohesion, the generation of metals and minerals, and so forth, by making an appeal to circulatory processes involving the interaction of metallic vapours, the atmosphere, and various forms of ether. This comprehensive theory emerges already in Newton’s early interpretation and summary of chymical theory, “Of Natures obvious laws and processes in vegetation,” where it is heavily indebted to early modern alchemist such as Michael Sendivogius (1566–1636) and Johann Grasseus (c. 1560–1623).^[14]

This post is already far too long and I’m going to break off here. If you want to learn more about Isaac’s alchemical endeavours than I suggest you read Newton the Alchemist: Science, Enigma, and the Quest for Nature’s “Secret Fire”.

^[1] William R. Newman, Newton the Alchemist: Science, Enigma, and the Quest for Nature’s “Secret Fire”, Princeton University Press, 2019

^[2] William R. Newman, A preliminary reassessment of Newton’s alchemy in The Cambridge Companion to Newton 2^nd ed., eds. Robert Iliffe and George E. Smith, CUP, 2016 pp. 454–484

^[3] Sandra Dry, The Newton Papers: The Strange & True Odyssey of Isaac Newton’s Manuscripts, OUP, 2014

^[4] Newman, Newton the Alchemist, p. 2

^[5] Newman, A preliminary reassessment, p. 454

^[6] Newman, Newton the Alchemist, p. 2

^[7] Rebekah Higgitt, Recreating Newton: Newtonian Biography and the Making of Nineteenth-Century History of Science, Pickering & Chatto, London, 2007.

^[8] Newman, Newton the Alchemist, p. 3

^[9] Newman, A preliminary reassessment, p. 462

^[10] Newman, A preliminary reassessment, p. 455

^[11] Quoted in Newman, A preliminary reassessment, pp. 479-80

^[12] Newman, A preliminary reassessment, p. 459

^[13] Newman, A preliminary reassessment, p. 466

^[14] Newman, A preliminary reassessment, pp. 468–9

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December 25, 2022 · 9:03 am

Christmas Trilogy 2022 Part 1: The amicable Isaac

There is a widespread popular view of Isaac Newton, the man, as an unfriendly cantankerous, argumentative, curmudgeonly nasty piece of work ready to start a slanging match at the drop of a bodkin, self-righteous, possessive, jealous, unable to accept any form of criticism. Summa summarum, not a nice person at all, in fact rather to be avoided if you know what’s good for you. This immediately raises the question, is it true? Was Newton such an anti-social monster, hidden in a dark corner of his chambers, biting the heads off kittens?

OK, my opening salvo is somewhat(?) hyperbolic but in general Isaac Newton is presented as an asocial, grumpy old man, who loved nobody and was loved by nobody. It might come as a surprise to some that this portrait is very one sided and, although he could never be described as gregarious, in fact, Isaac had acquaintances with whom he was on good terms, genuine friends and also that he was a kind and loving family man. What? He didn’t have a family, so how could he be a kind and loving family man? In what follows I present a brief, semi-chronological sketch, of the amicable Isaac.

Isaac Newton portrait 1702 by Godfrey Kneller Source: Wikimedia Commons

During his time as a fellow at Cambridge, Newton shared his chambers with two men, who both worked for him as an amanuensis. From 1663 to 1683, he shared with John Wickins, about whom we know almost nothing, although we do know from a letter written by Wickins’ son, in 1728, how the liaison came about:

My Father’s intimacy with him came by mere accident. My Father’s first Chamber-fellow being very disagreeable to him he retired one day into the walks where he found Mr Newton solitary & dejected; Upon entering into discourse they found their cause of Retirement the same &thereupon agreed to shake off their present disorderly Companions & Chum together, which they did as soon as conveniently they could &and so continued as long as my Father stayed at College. ^[1]

After Wickins left Cambridge to become vicar of Stock Edith, his place was taken by Humphrey Newton (a young man from Grantham who was no relation), who lived with Newton for five years. There is no record of any strife, disagreement, or whatever between Newton and his roommates, so at least here we can see an amicable Isaac.

Another Cambridge acquaintance, who we can fairly describe as a friend, was Charles Montagu (1661–1715), who later in his role as Chancellor of the Exchequer played an important role as Newton’s benefactor, giving him the position of Warden of the Mint in 1696, enabling his escape from Cambridge. They became friends when Montagu was a student and Newton already a professor and the depth of their friendship is demonstrated by the fact that Montagu used his political influence to have Newton appointed to the position at the Mint, when he wanted out of Cambridge. He even emphasised that it was a sinecure, and that Newton wasn’t actually required to do anything, although we know that Newton ignored this suggestion becoming a very active Warden and later Master.

Portrait of Charles Montagu by Is Godfrey Kneller Source: Wikimedia Commons

Apart from Montagu, the most important friendship Newton forged during his years at Cambridge was certainly that with Edmond Halley (1656–1742). It was Halley travelling to Cambridge in 1684 to ask Newton what shape the planetary orbits would be under an inverse squared law of gravity that lit the blue touch paper that led to the scientific explosion that is Philosophiæ Naturalis Principia Mathematica. Halley helped to pay the publishing cost of the Principia when the Royal society ran out of money. He also worked closely with Newton, particularly on the question of the flight paths of comets leading to his own Astronomae cometicae synopsis (A Synopsis of the Astronomy of Comets) in 1705, which contained his analysis of the orbit of what is now known as Comet Halley. The two men remained firm friends throughout Newton’s life, and he even helped Halley financially by appointing him deputy comptroller of the Chester Mint, a post he held for two years.

Portrait of Edmond Halley as Savilian Professor, artist unknown Source: Wikimedia Commons

Another academic protégé of Newton’s was David Gregory (1659–1708) the nephew of the astronomer and mathematician, with whom Newton was on good terms despite the fact the James Gregory (1638–1675) was a rival for the honour of having invented the reflecting telescope. Thanks to Newton’s support David Gregory was appointed Savilian Professor of Astronomer in 1691 at Oxford University. Newton’s support was somewhat surprising given that the other applicant was Halley. Gregory was a very active supporter of Newton’s work publishing his Astronomiae physicae et geometricae elementa, a semi-popular presentation of Newton’s theories in 1702.

Remaining with the academic side and Cambridge, Newton was on good terms with both Richard Bentley (1662–1742), who became Master of Trinity College, and William Whiston (1667–1752), who Newton had appointed as his successor as Lucasian Professor. Whiston was, like Gregory, a populariser of Newton’s work. When Whiston was expelled from Cambridge for being an Arian, Newton began to distance himself, afraid that his own unorthodoxy might become public. Bentley and Whiston were responsible for getting the prodigy Roger Cotes (1682–1716) appointed Plumian Professor at Cambridge. When Newton granted the privilege of editing the second edition of Principia to Richard Bentley, Bentley in turn entrusted the actual work to Cotes with Newton’s approval. Amongst other things Cotes added a preface to the book.

Engraving of Richard Bentley portrait by Arthur Thomas Malkin Source: Wikimedia Commons

Portrait of William Whiston artist unknown Source: Wikimedia Commons

Both William Whiston and Richard Bentley were, amongst other things, theologians, anther Cambridge theologian, who played an important positive role in Newton’s life was Samuel Clarke (1675–1729), who went into battle with Leibniz over the theological implications of Newton’s theory of gravity. Their exchanged letters form the Leibniz-Clarke correspondence an important document in the history of eighteenth-century science.

Samuel Clarke, portrait attributed to Charles Jervas. Source: Wikimedia Commons

Another, perhaps somewhat surprising, active supporter of Newton’s was the physician, satirist, and mathematician, John Arbuthnot (1667–1735), who was alongside Edmond Halley was one of Newton’s most important lieutenants. Perhaps surprising, because Arbuthnot was, like his friend Jonathan Swift, a staunch Tory, whereas Newton was very much a Whig. Newton had been a Whig MP for the University of Cambridge in 1689 and 1701 and was knighted in 1705 to get him re-elected in 1705, a strategy that failed. Also, his patron Charles Montagu was one of the most important Whig politicians of the period. All of this was doing a period of very intense political war between the two political parties, especially during the transition from the Stuart to the Hanoverian monarchy. Despite their positions on opposite sides of this deep political divide, Newton and Arbuthnot were good friends.

Portrait of John Arbuthnot attributed to Geoffrey Kneller Source: Wikimedia Commons

In my introductions I mentioned that Newton was a kind and loving family man, a comment likely to provoke a reaction from some. Newton was a half orphan from his birth on, never married and even claimed to be virgin, when he died, so what family? When Newton’s mother Hannah Newton-Smith née Ayscough died in 1679, he inherited the Newton estate, which provided him with an annual income of £600, making him a wealthy man. He also, so to speak, inherited his three half siblings from Hannah’s marriage to the Reverend Barnaby Smith. Despite being an absentee landowner took over direct management of his estate, a job that he carried out with his usual thoroughness. Also, aware of his responsibilities as the eldest he took care of his half siblings with great care. It is obvious from the surviving correspondence that he didn’t just do this out of a feeling of obligation but with genuine affection.

Most famously, when settled in London, he brought his half-niece Catherine Barton (1679–1739), the daughter of his half-sister Hannah and her husband the Reverend Robert Barton, to the city to act as his housekeeper, where she succeeded in establishing herself as a prominent member of society. Later, she married the landowner, politician and soldier, John Conduitt (1688–1737), who assisted Newton in his final years as Master of the Mint, inheriting his position when after Newton’s death.

Artist unknown Source: Wikimedia Commons

This painting by Hogarth shows a performance of a heroic drama, written by John Dryden (1631–1700) and first performed in 1665, being performed by a group of children in the drawing room of the town house of John Conduitt (1688–1737), the husband of Newton’s niece and one time housekeeper, Catherine Barton; Conduitt was also Newton’s successor as Master of the Mint.

Without doubt the highest level of affection displayed by Newton was in the letter he exchanged with the young Swiss mathematician Nicolas Fatio de Duillier (1664-1753) in the early 1690s. Those very intimate letters that can, without a very great stretch of the imagination, be described as love letters. We don’t know if it was purely platonic or an active physical relationship. A third possibility, as I wrote in an earlier blog post, is, Newton having perhaps seen something of himself in the young Fatio had adopted him like a mother hen. The tone of some of Newton’s letters would certainly support such an interpretation.

Fatio c. 1700 Artist unknown
Source: Wikimedia commons

Coffee shops were all the rage in early eighteenth-century London, and when he became established and President of the Royal Society, Newton would hold court at his favourite coffee shop, surrounded by his acolytes, distributing wisdom, and passing around his treasure trove of unpublished mathematical papers. Participants in these sessions included such as Edmond Halley and David Gregory, when in London, but also Gregory’s fellow Scots, the Keill brothers, the physician James (1673–1719) and the mathematician John (1671–1721), who famously ignited the dispute with Leibniz over the invention of the calculus. Also often present was the Huguenot refugee, Abraham de Moivre (1667–1754).

Portrait of Abraham de Moivre artist unknown Source: Wikimedia Commons

A late addition was the Welsh mathematician, William Jones (1675–1749), famous for being the first to use π for the ration of circumference to diameter of the circle.

Towards the end of his life Newton formed a strong friendship with the physician and antiquarian William Stukeley (1687–1765), who like Isaac was a Lincolnshire lad. Stukeley wrote one of the earliest biographies of Newton, which is one of the sources of the infamous apple story.

Perhaps the strangest of Newton’s friendships was with Caroline of Brandenburg-Ansbach (1683–1737), daughter-in-law to George I and wife of George II, who came to England in 1714 with her father-in-law. A woman of intelligence she was friends with both John Arbuthnot and Jonathan Swift. She corresponded with Leibniz, her father-in-law’s librarian, and facilitated the Leibniz-Clarke correspondence. Newton was comparatively oft a visitor to St James’ Palace, Caroline’s residence, where the two of them would indulge in long philosophical discussions.

Portrait of Caroline in 1716 by Godfrey Kneller Source: Wikimedia Commons

I hope that in this brief sketch I have managed to convey a different view of Isaac Newton to the usual popular cliché of the grumpy and aggressive introvert ready, as I said, to pick an argument at the drop of a bodkin.

^[1] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, CUP, Cambridge etc., 1980 p. 74

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March 2, 2022 · 7:44 am

Chronology, history, or prophecy?

Bible chronology is a fascinating Early Modern intellectual phenomenon that combines science, history, and theology. Put simply, it is basically the attempt, assuming the Old Testament to be true and historically accurate, to develop the time frame of that history bringing into accord with what was known of the histories of the ancient cultures and calculate backwards to the point of God’s creation of the world. Although aware of its existence for a long time I paid it little heed because there were/are so many other things that interest me and occupy my time. This changed when the so-called gnu-atheists, whom I regard as smug ignoramuses, who give atheism a bad name, started to mock the Irish mathematician and theologian, James Ussher, Archbishop of Armagh, and Primate of All Ireland, on the “earth’s birthday”, 22 October, the date that Ussher calculated for the day of creation in his Bible chronology. A date well known amongst Protestants because it was enshrined in the Book of Common Prayer. I took up cudgels on Ussher’s behalf and wrote a blog post, In defence of the indefensible, pointing out that in the framework within which Ussher was working his calculations were in fact totally rational. In this post I wrote amongst other things:

Ussher was by no means the only prominent Bible chronologist of the 16^th and 17^thcenturies the most famous being the philologist and historian Joseph Justus Scaliger and of course Isaac Newton; others such as Johannes Kepler and Phillip Melanchthon also dabbled.

Now, it is well known that I am interested in everything that Isaac Newton indulged in during his long and unbelievably productive life, but that unbelievable productivity is exactly the problem. Newton wrote literally millions of words over a vast range of topics. If James Brown could crown himself, the hardest working man in show business, then Newton could crown himself the hardest working man in the history of science. Although I did write a brief post sketching Newton’s involvement in Bible chronology entitled, Newton was one too, the topic got put very definitely on the back burner. I wrote another post on Bible chronology, about Joseph Justus Scaliger’s involvement, Counting the days, because his Julian Year Count, converted to the Julian Day Count became, in the nineteenth century, the universal dating system for astronomers.

Returning to Newton’s impossibly vast intellectual output, most people over the decades and centuries since his death concentrated on his mathematics, astronomy, and physics, actually by far the smallest part, whilst quietly ignoring the rest. There have been notable exceptions, which I’m not going to list here, but they were on the whole piecemeal. In more recent times the historian Rob Iliffe set up the Newton Project to systematically edit, comment upon, and make available Newtons vast inheritance, initially in Cambridge, and then somewhat ironically moving the whole to Oxford University, where it still current resides. There is a parallel Chymistry of Isaac Newton project at Indiana University. The Newton Project has been producing first class results and publishing first class material, such as Iliffe’s Priest of Nature: The Religious Worlds of Isaac Newton (OUP, 2019) for some time now and one of the most recent publications is Cornelius J Schilt, Isaac Newton and the Study of Chronology: Prophecy, History, and Method (Amsterdam University Press, 2021), which could also be titled everything you ever wanted to know about Bible chronology in general and Isaac Newton’s involvement in it in particular. Yes, it really is that comprehensive!

The first thing to note is that this is a very serious piece of academic research and not in anyway a popular book. However, Schilt writes in a clear accessible style, so that anybody, who is interested, and is prepared to invest the effort can read the book with profit, even if they come to the topic as Bible chronology virgins, so to speak.

A short introduction sets out the purpose of Schilt’s research, the problems that it entailed and a brief guide to the sections of the book. It closes with an unusually feature of the book. Instead of the usual massive bibliography at the end of the book, each section, and I will explain the sections shortly, closes with an, often extensive, bibliography for that section. The book is divided into four sections, each of which deals with a different aspect of Newton’s work and Schilt’s research into that work.

The first section is a comparatively short and concise, but highly informative, explanation of what exactly Bible chronology was in the Early Modern period. It illustrates how individual Bible chronologist approached the topic and what they hoped to achieve through their work. Having explained Bible chronology, Schilt closes the section with the question, Isaac Newton … Chronologist? Here Schilt discusses Newton’s two published chronology text, the first during his lifetime and heavily criticised and the second put together from his convolute of manuscripts by his acolytes after his death. Here Schilt touches upon, for the first time, the sheer volume of manuscripts and manuscript fragments on the topic, none of them noticeable finished, that Newton left behind in a total chaos, when he died, for historians to try and make some sort of sense out of. This section closes with an extremely extensive bibliography. If one just wished to read an introduction to Bible chronology and not Newton’s work in particular, then this section provides an excellent one.

In the second section, Schilt introduces the reader to the mind of Isaac Newton and how it worked when he was producing his chronological work. We start with his library, the books he owned. The books that he read to inform himself about ancient history. Primary text by ancient authors for their historical content. Books by contemporary authors for information about which other ancient books he should read. Lists of books that he wished to acquire to further his knowledge. This is followed by Newton’s note taking habits. Here we run into major problems of which I was already aware from other areas of Newton’s work, mathematics, physics, astronomy. Newton was anything but organised in his note taking, using random sheets of paper, using the same sheet two-times years apart etc. etc. How Newton marked passages in books, not by underlining but by dogearing pages bending them over so far that the corner pointed to the passage in question.

The section closes out with a discussion of the fact Newton was an outsider, an independent scholar with no connections to others working in the same or related fields. Newton worked for himself not with others.

The second section makes very obvious that on a meta-level throughout the book we also get a very clear picture of how the researcher, Schilt, worked. He doesn’t just present the results of his research but outlines in detail how he extracted his results from the chaos that is both Newton’s papers and his approaches to his work over the years. This meta-level continues throughout the book and gives powerful insights into how to approach such a research task and carry it through to completion.

The third section takes the reader into the development history of Newton’s earliest chronological treatise, Theologiae gentilis origines philosophicae, known as Origines for short created literally over decades. This is simply not a working manuscript but an extensive collection of manuscripts, fragments, paragraphs, chapters, outlines. Schilt takes his reader through his analysis of what belongs where and why. Explaining his reasons for dating various pieces of writing and why he thinks over separately produced manuscripts belong to the Origines.

The reader gets presented with a master class in academic research detective work.

In the fourth and final section, Schilt does the same for the Chronology of Ancient Kingdoms Amended, as he did for Origines in section three. This is the manuscript on which Newton was working when he died, and which was edited and published by John Conduitt and Martin Folkes. Schilt also delivers a deep analysis as to why Newton was involved in chronological studies at all. Another master class in academic research detective work. As with the first two sections two and three both have their own bibliographies.

I’m not going to go into any details of what Newton is trying the achieve with his chronological work, you’ll have to read the book for that, but his work is very different from that of the other Bible chronologists that the reader meets in section one. At the end of that first segment Schilt poses the question, is Newton a chronologist. His conclusion at the end of the fourth section is no he isn’t really. Newton’s chronology serves the higher purpose of helping him to analyse the Bible prophecies a central concern of his whole approach to religion.

The book closes with “Some Concluding Remarks” which gives a one sentence summary of the book better then any I could create:

In this book, I have purposely presented the narrative of Newton’s chronological studies from the bottom up, as a quest in search of the real Chronology of Ancient Kingdoms Amended and the real Newton

This he does brilliantly. He goes on the point out that given the vast quantity of manuscript material that Newton left behind when he died and which became spread out all over the world when Newton’s papers were sold off in public auction in the 1930s, his work and the work in general of the Newton Project and the Chymistry of Isaac Newton project, has only become possible because of digitation of the material making it available to researchers.

The book is excellently presented, it closes with another general bibliography and an excellent index. Each of the four sections starts with a clear and informative short abstract explaining its contents. It has extensive footnotes, not the dreaded endnotes. There are illustrations that are just excerpts from manuscripts, which, however, are interesting as they often show Newton actively editing his work. There are also diagrammatical presentations of Schilt’s reconstructions of the order in which individual pieces of work were created and how various manuscripts fit together (see above).

I suspect Schilt’s book is compulsory reading for any serious student of the whole Newton, i.e., not just those interested in the maths and physics and also for scholars of Bible chronology. However, I think it can also be read by those more generally interested in Newton the man, a complex, puzzling and totally fascinating figure. Schilt has opened another window on that conundrum that is J M Keynes’ “the last of the magicians” Woolsthorpe’s finest, Isaac Newton.

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Filed under Book Reviews, Newton

January 10, 2022 · 10:06 am

STOMP, STOMP, STOMP … NEWTON DID WOT!

Oh dear! The HISTSCI_HULK has been woken from his post festive slumbers and is once again on the rampage. What has provoked this outbreak so early in the new year? He chanced to see a post, that one of my followers on Facebook had linked to, celebrating Newton’s new-style birthday on 4 January. As is well-known, we here at the Renaissance Mathematicus celebrate Newton’s old-style birthday, but that’s another story.

The post is on a website called Wonders of Physics, is the work of an Indian physicist, Vedang Sati, and is titled:

10 Discoveries By Newton That Changed The World

I have reproduced the whole horror show below. Let us examine it.

Isaac Newton is one of the few names that will forever be enshrined in physics history and that too with a lot of glamour associated. Contributions of none other physicist match, his, well, Einstein’s, or not even his!? The following are Newton’s ten most well-known works that changed the world later on.

A strong hagiographical vibe going down here, which doesn’t bode well.

Laws of motion
1. An object will remain at rest or move in a straight line unless acted upon by an external force.
2. F=ma.
3. For every action, there is an equal and opposite reaction.

Newton’s three laws of motion, along with thermodynamics, stimulated the industrial revolution of the 18th and 19th centuries. Much of the society built today owes to these laws.

Remember these are supposedly the things that Newton discovered. His first law of motion, the law of inertia, was first formulated by Galileo, who, however, thought it only applied to circular motion. For linear motion it was first formulated by Isaac Beeckman and taken over from him by both René Descartes and Pierre Gassendi. Newton took it from Descartes. The second law, which was actually slightly different in the original form in which Newton used it, was taken from Christiaan Huygens. The third law was probably developed out of the studies of elastic and inelastic collision, which again originates by Descartes, who got much wrong which was corrected by both Huygens and Newton. Newton’s contribution was to combine them as axioms from which to deduce his mechanics, again probably inspired by Huygens. He tried out various combinations of a range of laws before settling on these three. Sati’s following statement is quite frankly bizarre, whilst not totally false. What about the Principia, where they occur, as the foundation of classical mechanics and perhaps more importantly celestial mechanics.

Binomial Theorem
Around 1665, Isaac Newton discovered the Binomial Theorem, a method to expand the powers of sum of two terms. He generalized the same in 1676. The binomial theorem is used in probability theory and in the computing sciences.

The binomial theorem has a very long history stretching back a couple of thousand years before Newton was born. The famous presentation of the binomial coefficients, known as Pascal’s Triangle, which we all learnt in school (didn’t we?), was known both to Indian and Chinese mathematicians in the Middle Ages. Newton contribution was to expand the binomial theorm to the so-called general form, valid for any rational exponent.

Inverse square law
By using Kepler’s laws of planetary motion, Newton derived the inverse square law of gravity. This means that the force of gravity between two objects is inversely proportional to the square of the distance between their centers. This law is used to launch satellites into space.

I covered this so many times, it’s getting boring. Let’s just say the inverse square law of gravity was derived/hypothesized by quite a few people in the seventeenth century, of whom Newton was one. His achievement was to show that the inverse square law of gravity and Kepler’s third law of planetary motion are mathematically equivalent, which as the latter in derived empirically means that the former is true. Newton didn’t discover the inverse square law of gravity he proved it.

Newton’s cannon
Newton was a strong supporter of Copernican Heliocentrism. This was a thought experiment by Newton to illustrate orbit or revolution of moon around earth (and hence, earth around the Sun)

He imagined a very tall mountain at the top of the world on which a cannon is loaded. If too much gunpowder is used, then the cannon ball will fly into space. If too little is used, then the ball wouldn’t travel far. Just the right amount of powder will make the ball orbit the Earth.

This thought experiment was in Newton’s De mundi systemate, a manuscript that was an originally more popular draft of what became the third book of the Principia. The rewritten and expanded published version was considerably more technical and mathematical. Of course, it has nothing to do with gunpowder, but with velocities and forces. Newton is asking when do the inertial force and the force of gravity balance out, leading to the projectile going into orbit. It has nothing to do directly with heliocentricity, as it would equally apply to a geocentric model, as indeed the Moon’s orbit around the Earth is. De mundi systemate was first published in Latin and in an English translation, entitled A Treatise of the System of the World posthumously in 1728, so fifty years after the Principia, making it at best an object of curiosity and not in any way world changing.

Calculus
Newton invented the differential calculus when he was trying to figure out the problem of accelerating body. Whereas Leibniz is best-known for the creation of integral calculus. The calculus is at the foundation of higher level mathematics. Calculus is used in physics and engineering, such as to improve the architecture of buildings and bridges.

This really hurts. Newton and Leibniz both collated and codified systems of calculus that included both differential and integral calculus. Neither of them invented it. Both of them built on a two-thousand-year development of the discipline, which I have sketch in a blog post here. On the applications of calculus, I recommend Steven Strogatz’s “Infinite Powers”

Rainbow
Newton was the first to understand the formation of rainbow. He also figured out that white light was a combination of 7 colors. This he demonstrated by using a disc, which is painted in the colors, fixed on an axis. When rotated, the colors mix, leading to a whitish hue.

In the fourteenth century both the German Theodoric of Freiberg and the Persian Kamal al-Din al-Farsi gave correct theoretical explanations of the rainbow, independently of one another. They deliver an interesting example of multiple discovery, and that scientific discoveries can get lost and have to be made again. In the seventeenth century the correct explanation was rediscovered by Marco Antonio de Dominis, whose explanation of the secondary rainbow was not quite right. A fully correct explanation was then delivered by René Descartes.

That white light is in fact a mixture of the colours of the spectrum was indeed a genuine Newton discovery, made with a long series of experiments using prisms and then demonstrated the same way. Newton’s paper on his experiments was his first significant publication and, although hotly contested, established his reputation. It was indeed Newton, who first named seven colours in the spectrum, there are in fact infinitely many, which had to do with his arcane theories on harmony. As far as can be ascertained the Newton Disc was first demonstrated by Pieter van Musschenbroek in 1762.

Reflecting Telescope
In 1666, Newton imagined a telescope with mirrors which he finished making two years later in 1668. It has many advantages over refracting telescope such as clearer image, cheap cost, etc.

Once again, the reflecting telescope has a long and complicated history and Newton was by no means the first to try and construct one. However, he was the first to succeed in constructing one that worked. I have an article that explains that history here.

Law of cooling
His law states that the rate of heat loss in a body is proportional to the difference in the temperatures between the body and its surroundings. The more the difference, the sooner the cup of tea will cool down.

Whilst historically interesting, Newton’s law of cooling holds only for very small temperature differences. It didn’t change the world

Classification of cubics
Newton found 72 of the 78 “species” of cubic curves and categorized them into four types. In 1717, Scottish mathematician James Stirling proved that every cubic was one of these four types.

Of all the vast amount of mathematics that Newton produced, and mostly didn’t publish, to choose his classification of cubics as one of his 10 discoveries that changed the world is beyond bizarre.

Alchemy
At that time, alchemy was the equivalent of chemistry. Newton was very interested in this field apart from his works in physics. He conducted many experiments in chemistry and made notes on creating a philosopher’s stone.
Newton could not succeed in this attempt but he did manage to invent many types of alloys including a purple copper alloy and a fusible alloy (Bi, Pb, Sn). The alloy has medical applications (radiotherapy).

Here we have a classic example of the Newton was really doing chemistry defence, although he does admit that Newton made notes on creating a philosopher’s stone. If one is going to call any of his alloys, world changing, then surely it should be speculum, an alloy of copper and tin with a dash of arsenic, which Newton created to make the mirror for his reflecting telescope, and which was used by others for this purpose for the next couple of centuries.

Of course, the whole concept of a greatest discovery hit list for any scientist is totally grotesque and can only lead to misconceptions about how science actually develops. However, if one is going to be stupid enough to produce one, then one should at least get one’s facts rights. Even worse is that things like the classification of the cubics or Newton’s Law of Cooling are anything but greatest discoveries and in no way “changed the world.”

You might wonder why I take the trouble to criticise this website, but the author has nearly 190,000 followers on Facebook and he is by no means the only popular peddler of crap in place of real history of science on the Internet. I often get the feeling that I and my buddy the HISTSCI_HULK are a latter-day King Cnut trying to stem the tide of #histSTM bullshit.

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Filed under History of science, Myths of Science, Newton

December 25, 2021 · 8:30 am

Christmas Trilogy 2021 Part 1: The evolving views of the Last of the Magicians

Some time back, it seemed that several times a year someone would post an article or a blog post on the Internet along the lines of, “Shock! Horror! Outrage! did you know that Isaac Newton was a practicing alchemist?” All the historians of science, who know their Newton, would shrug their shoulders, and quietly repeat, actually we have known about this for a long time. It is quite interesting to look at how the views of Newton the alchemist have changed over time, but first a little bit of general background on his alchemical activities.

There are two more or less popular takes from people who have never bothered to investigate the topic. There are those, who claim that Newton merely dabbled a bit in alchemy, so historian shouldn’t take it seriously. Others claim that Newton first took up alchemy in his dotage, after his scientific career was over, an old man’s foible. Both of these are fundamentally wrong.

Newton was a dedicated student and practitioner of alchemy for thirty years from 1666 to 1696, massively reducing his engagement when he moved to London. He had a shed built in the gardens of Trinity College, which he used as his alchemical laboratory for six weeks before the start of winter and six weeks at the end of winter every year.

Isaac Newton’s rooms. View of the rooms occupied by Sir Isaac Newton (1642-1727) at Trinity College, Cambridge. His rooms were on the first floor between the Great Gate and the Chapel. The small room projecting from the Chapel was probably his alchemical laboratory. Source:

This is of course the same period in which he did all of his ground-breaking work in mathematics, astronomy, physics, and optics. In these decades, he also did extensive work on theology and historical chronology. I sometimes get the impression that he never slept.

He accumulated a substantial library of books on alchemy, as well of hermeticism, at least 170 titles. There are quite literally reams of his writings on alchemy, a total of over one million words! He took notes on his readings and even copied out pages of some alchemical texts. Apparently, Newton seldom made annotations in the books that he owned but he heavily annotated two of his alchemical volumes, Eyraeneus Philaletha Cosmopolita, aka George Starkey’s Secrets Reveal’d and Lazarus Zetzner’s Theatrum chemicum.^{^[1]}

From his readings, Newton complied lexica of alchemical symbols and veiled terms in an attempt to decode the texts he was consuming. It is very obvious that Newton’s engagement was very serious and on a very large scale.

So, how did his contemporaries react to Newton’s alchemical activities? The straightforward answer is they didn’t because they didn’t know about them. Newton stuck to, what might be termed, the alchemists’ honour code that is only to communicate about his alchemical activities with other adepts and even then, in veiled terms. He even once rebuked Robert Boyle, a fellow practitioner, for publishing an article on alchemy.

When Newton died, his papers passed into the possession of his half-niece Catherine Barton and her husband John Conduitt. When they died the papers passed into the possession of their only daughter Catherine, who was born in 1721. In 1740, Catherine married John Wallop, Viscount Lymington, the eldest son of the Earl of Portsmouth. Catherine’s son John Wallop inherited the title from his grandfather in 1762. John Wallop senior had died in 1742. Newton’s papers, now in possession of the Portsmouth family were stored in a trunk and basically forgotten about for about for more than a century.

In 1872, Isaac Newton Wallop^[2], 5^th Earl of Portsmouth donated Newton’s papers to Trinity College both his and Newton’s alma mater.

*“Horseflesh”*, the 5th Earl of Portsmouth, caricature by Spy in Vanity Fair, 1 July 1876. Source: Wikimedia Commons

A committee chaired by the astronomer John Couch Adams and the physicist George Stokes was set up to review the papers. In a process that lasted sixteen years, this committee only selected Newton’s mathematical and scientific papers rejecting the rest to protect the reputation of their scientific hero. The bulk of the papers were returned to the Portsmouth family. One could describe this action as, “if we ignore Newton’s alchemical, theological, and chronological activities, then we can pretend they never took place”.

This committee’s behaviour was not the only negative reaction to Newton’s alchemical activities during the nineteenth century. In 1831, the Scottish physicist, David Brewster (1781–1868),

Inner picture of a cigar box from the early 1900s with a portrait of Brewster. Source: Wikimedia Commons

nowadays best known in popular culture as the inventor of the kaleidoscope, published a hagiographical biography of his personal hero Isaac Newton, The Life of Sir Isaac Newton (J. Murry, 1831), as a reaction to the, as he saw it, denigrating biography written by the French astronomer, physicist, and mathematician, Jean-Baptiste Biot (1774–1862) and published in 1822. During the research for his biography, Brewster was mortified when he discovered that his hero had dabbled in alchemy, he wrote:

There is no problem of more difficult solution than that which relates to a belief in alchemy … by men of high character and lofty attainments.

He further argued that Newton was of “a peculiar bent of mind”, the same mind that was otherwise “of such a power and so nobly occupied with the abstraction of geometry.”

Brewster also refused to believe that Newton was a unitarian, stating that he was upright, orthodox, church-going Anglican. This led to a dispute with Augustus De Morgan (1806–1871, himself a unitarian, who vigorously defended Newton’s Unitarianism. Newton, in fact, devoted a lot of time and effort trying to prove that the Catholic Church had falsified the Bible to create the Trinitarian doctrine^[3].

In 1936, the Portsmouth family sold of the baulk of Newton’s papers by public auction. An act that brings tears to the eyes of every dedicated historian of science. Fortunately, the economist John Maynard Keynes (1883–1946), a true Cambridge man born so to speak, into the university, his father was a Cambridge lecturer, bought up a large chunk of Newton’s papers, also acquiring other papers from other buyers after the auction and donated them to King’s College Library.

Caricature of J M Keynes by David Low, 1934

He read through the documents that he had acquired and like Brewster was disappoint that his hero was a practicing alchemist and baptised him, in an essay, “the last of the magicians”, hence the title of this post. He also wrote “the last wonder child to whom the Magi could do sincere and appropriate homage.” Like Brewster he couldn’t understand why Newton would engage in something “wholly devoid of scientific value” and viewing Newton’s obsession as an aberration stated, “geniuses are very peculiar.”

In the late 1950s, two professional historians of science, Rupert Hall (1920–2009) and Marie Boas (1919–2009), began to examine the Portsmouth papers and came up with a, for professionals, peculiar reaction, in that they simply denied that Newton had practiced alchemy. For Hall and Boas, it was unthinkable that the scientist Newton would indulge in anything so unscientific as alchemy, what he was doing was legitimate chemistry and be merely consulted alchemical texts for their descriptions of laboratory methods. Well after all, nearly all the standard laboratory analytical practices in chemistry were devised/discovered/created/invented by alchemists. To be fair to Hall and Boas, Newton did in fact use the knowledge of chemical analysis that he had acquired through his alchemical activities to devise new, improved methods for assaying metals, when working at the Royal Mint. It was also Hall and Boas, who insisted that Newton’s “chemical activities” took place after he had effectively stopped producing real science and mathematics. The old man dabbling. I think the most charitable thing one can say about Hall and Boas’ efforts is, there are none so blind as those that will not see.

The Big Bang in research into Newton’s alchemy can be dated to the publication of The Foundations of Newton’s Alchemy, or the Hunting of the Green Lyon by Betty Jo Teeter Dobbs (1930–1994) in 1975 by CUP.

Here was a full-length monograph that dealt with Newton’s alchemy, as alchemy, in great depth and detail. No denial, no repulsion, just a highly readable but seriously academic analysis of the alchemical activities of the good Isaac, without value judgement. It was through this book that I first became aware of Newton the alchemist and the book also changed my attitude to the so-called occult sciences. Like most people of my generation, these were not science and so were not of interest to an apprentice historian of science. These days I spend at least as much time and effort defending the study of the occult science, as I do the “real” sciences.

Dobbs wrote several more books on Newton’s alchemy and how it fitted, in her opinion, into the rest of his activities, both scientific and theological. Important in the acceptance of her work was the active support that she and her theories received from Richard Westfall (1924–1996), author of the, up till now, best biography of Newton, Never at Rest CUP, 1980). As well as establishing beyond any reasonable doubt that Newton was a serious alchemist, Dobbs developed a theory based on her interpretation of the evidence that Newton had adopted the concept of action at a distance, against the prevailing mechanical philosophy leading to severe criticism from Leibniz and the Cartesians, from his alchemical research. This theory found a lot of general acceptance and up till recently, I too accepted it.

In 1988, Oxford University Press published a reader Let Newton Be! A new perspective on his life and works, with essays on all aspects of his work including his occult activities. Two of the essays Newton, matter, and magic by John Henry and The secret life of an alchemist by Jan Golinski accept and deal with Newton’s alchemy as a normal part of his intellectual makeup. Both accept Dobbs’ hypothesis that Newton’s concept of force derived from concepts of occult power.

In 2016, Cambridge University Press published the second edition of their Newton reader, The Cambridge Companion to Newton, which contains an essay from William R. Newman, one of a group of prominent historians of alchemy, who in recent years have completely rewritten the history of the topic. In his essay, A preliminary reassessment of Newton’s alchemy, Newman effectively demolishes the Dobbs theory showing that it doesn’t work. Instead, he proposes a new theory that Newton’s alchemical studies influenced his optic investigations in the late 1660s.

Newman was working on an in-depth study and analysis of Newton’s alchemy, which appeared as a book in 2018, Newton the Alchemist: Science, Enigma, and the Quest for Nature’s “Secret Fire” (Princeton University Press).

This will certainly prove to be the definitive account of Newton’s alchemy for the next years and my copy is somewhere near the top of my to read list, I hope to delve not to far in the future.

Over the centuries the reactions to Newton the alchemist have gone from ignorance, we didn’t know he was one, to abhorrence and bewilderment, to if we ignore it it doesn’t exist, to acceptance and serious historical analysis.

^[1] I owe this snippet of information to Cornelius J. Schilt’s excellent Isaac Newton and the Study of Chronology: Prophecy, History, and Method (Amsterdam University Press, 2021) p. 96. The book is my current bedtime reading and a review will follow sometime next year.

^[2] Yes, that really is his name!

^[3] For an excellent analysis of the 19^th century Newton biographies I heartily recommend Rebekah Higgitt’s Recreating Newton: Newtonian Biography and the Making of Nineteenth-Century History of Science (Pickering & Chatto, 207), which I reviewed here

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Christmas Trilogy 2025 Part 1: Pictures of Isaac

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STOMP, STOMP, STOMP … NEWTON DID WOT!

Christmas Trilogy 2021 Part 1: The evolving views of the Last of the Magicians

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