The Net

Early life

Isaac Newton was born (according to the Julian calendar in use in England at the time) on Christmas Day, 25 December 1642 (NS 4 January 1643) at Woolsthorpe Manor in Woolsthorpe-by-Colsterworth, a hamlet in Lincolnshire. His father, also named Isaac Newton, had died three months before. Born prematurely, Newton was a small child; his mother, Hannah Ayscough, said that he could have fit inside a quart mug. When Newton was three, his mother remarried and went to live with her new husband, the Reverend Barnabas Smith, leaving her son in the care of his maternal grandmother, Margery Ayscough (née Blythe). Newton disliked his stepfather and maintained some enmity towards his mother for marrying him, as revealed by this entry in a list of sins committed up to the age of 19: "Threatening my father and mother Smith to burn them and the house over them." Newton's mother had three children (Mary, Benjamin, and Hannah) from her second marriage.

The King's School

From the age of about twelve until he was seventeen, Newton was educated at The King's School in Grantham, which taught Latin and Ancient Greek and probably imparted a significant foundation of mathematics. He was removed from school by his mother and returned to Woolsthorpe by October 1659. His mother, widowed for the second time, attempted to make him a farmer, an occupation he hated. Henry Stokes, master at The King's School, and Reverend William Ayscough (Newton's uncle) persuaded his mother to send him back to school. Motivated by a desire for revenge against a schoolyard bully, whom Newton beat in a fight and humiliated, he became the top-ranked student, distinguishing himself mainly by building sundials and models of windmills.

University of Cambridge

In June 1661, Newton was admitted to Trinity College at the University of Cambridge. His uncle the Reverend William Ayscough, who had studied at Cambridge, recommended him to the university. At Cambridge, Newton started as a subsizar, paying his way by performing valet duties until he was awarded a scholarship in 1664, which covered his university costs for four more years until the completion of his MA. At the time, Cambridge's teachings were based on those of Aristotle, whom Newton read along with then more modern philosophers, including René Descartes and astronomers such as Galileo Galilei and Thomas Street. He set down in his notebook a series of "Quaestiones" about mechanical philosophy as he found it. In 1665, he discovered the generalised binomial theorem and began to develop a mathematical theory that later became calculus. Soon after Newton obtained his BA degree at Cambridge in August 1665, the university temporarily closed as a precaution against the Great Plague.

Although he had been undistinguished as a Cambridge student, his private studies and the years following his bachelor's degree have been described as "the richest and most productive ever experienced by a scientist". The next two years alone saw the development of theories on calculus, optics, and the law of gravitation, at his home in Woolsthorpe. The physicist Louis Trenchard More writes that "There are no other examples of achievement in the history of science to compare with that of Newton during those two golden years."

Newton has been described as an "exceptionally organized" person when it came to note-taking, further dog-earing pages he saw as important. Furthermore, Newton's "indexes look like present-day indexes: They are alphabetical, by topic." His books showed his interests to be wide-ranging, with Newton himself described as a "Janusian thinker, someone who could mix and combine seemingly disparate fields to stimulate creative breakthroughs." William Stukeley wrote that Newton "was not only very expert with his mechanical tools, but he was equally so with his pen", and further illustrated how Newton's lodging room wall at Grantham was covered in drawings of "birds, beasts, men, ships & mathematical schemes. & very well designed". He also noted his "uncommon skill & industry in mechanical works".

In April 1667, Newton returned to the University of Cambridge, and in October he was elected as a fellow of Trinity. Fellows were required to take holy orders and be ordained as Anglican priests, although this was not enforced in the Restoration years, and an assertion of conformity to the Church of England was sufficient. He made the commitment that "I will either set Theology as the object of my studies and will take holy orders when the time prescribed by these statutes [7 years] arrives, or I will resign from the college." Up until this point he had not thought much about religion and had twice signed his agreement to the Thirty-nine Articles, the basis of Church of England doctrine. By 1675 the issue could not be avoided, and his unconventional views stood in the way.

Revision of Geographia Generalis

The Lucasian Professor of Mathematics at Cambridge position included the responsibility of instructing geography. In 1672, and again in 1681, Newton published a revised, corrected, and amended edition of the Geographia Generalis, a geography textbook first published in 1650 by the then-deceased Bernhardus Varenius. In the Geographia Generalis, Varenius attempted to create a theoretical foundation linking scientific principles to classical concepts in geography, and considered geography to be a mix between science and pure mathematics applied to quantifying features of the Earth. While it is unclear if Newton ever lectured in geography, the 1733 Dugdale and Shaw English translation of the book stated Newton published the book to be read by students while he lectured on the subject. The Geographia Generalis is viewed by some as the dividing line between ancient and modern traditions in the history of geography, and Newton's involvement in the subsequent editions is thought to be a large part of the reason for this enduring legacy.

Scientific studies

Mathematics

Newton's work has been said "to distinctly advance every branch of mathematics then studied". His work on calculus, usually referred to as fluxions, began in 1664, and by 20 May 1665 as seen in a manuscript, Newton "had already developed the calculus to the point where he could compute the tangent and the curvature at any point of a continuous curve". His work by 1665 amounted to a systematic calculus that unified differentiation and integration, which he applied to the dynamic analysis of algebraic and transcendental curves, an approach described by scholar Tom Whiteside as "radically novel, indeed unprecedented" and which later directly informed the theory of central-force orbits in the Principia. Another manuscript of October 1666, is now published among Newton's mathematical papers. Newton recorded a definitive tract of calculus in what is called his "Waste Book". He was self-taught in mathematics and did his research without help, as according to scholar Richard S. Westfall, "By every indication we have, Newton carried out his education in mathematics and his program of research entirely on his own." His work De analysi per aequationes numero terminorum infinitas, sent by Isaac Barrow to John Collins in June 1669, was identified by Barrow in a letter sent to Collins that August as the work "of an extraordinary genius and proficiency in these things".

Newton later became involved in a dispute with the German polymath Gottfried Wilhelm Leibniz over priority in the development of calculus. Both are now credited with independently developing calculus, though with very different mathematical notations. However, it is established that Newton came to develop calculus much earlier than Leibniz. Despite this, the notation of Leibniz is recognised as the more convenient notation, being adopted by continental European mathematicians, and after 1820, by British mathematicians.

The historian of science A. Rupert Hall notes that while Leibniz deserves credit for his independent formulation of calculus, Newton was undoubtedly the first to develop it, stating:But all these matters are of little weight in comparison with the central truth, which has indeed long been universally recognized, that Newton was master of the essential techniques of the calculus by the end of 1666, almost exactly nine years before Leibniz . . . Newton's claim to have mastered the new infinitesimal calculus long before Leibniz, and even to have written — or at least made a good start upon — a publishable exposition of it as early as 1671, is certainly borne out by copious evidence, and though Leibniz and some of his friends sought to belittle Newton's case, the truth has not been seriously in doubt for the last 250 years. Hall further notes that in Principia, Newton was able to "formulate and resolve problems by the integration of differential equations" and "in fact, he anticipated in his book many results that later exponents of the calculus regarded as their own novel achievements." Hall notes Newton's rapid development of calculus in comparison to his contemporaries, stating that Newton "well before 1690 . . . had reached roughly the point in the development of the calculus that Leibniz, the two Bernoullis, L'Hospital, Hermann and others had by joint efforts reached in print by the early 1700s".

Optics

In 1666, Newton observed that the spectrum of colours exiting a prism in the position of minimum deviation is oblong, even when the light ray entering the prism is circular, which is to say, the prism refracts different colours by different angles. This led him to conclude that colour is a property intrinsic to light – a point which had, until then, been a matter of debate.

From 1670 to 1672, Newton lectured on optics. During this period he investigated the refraction of light, demonstrating that the multicoloured image produced by a prism, which he named a spectrum, could be recomposed into white light by a lens and a second prism. Modern scholarship has revealed that Newton's analysis and resynthesis of white light owes a debt to corpuscular alchemy.

In his work on Newton's rings in 1671, he used a method that was unprecedented in the 17th century, as "he averaged all of the differences, and he then calculated the difference between the average and the value for the first ring", in effect introducing a now standard method for reducing noise in measurements, and which does not appear elsewhere at the time. He extended his "error-slaying method" to studies of equinoxes in 1700, which was described as an "altogether unprecedented method" but differed in that here "Newton required good values for each of the original equinoctial times, and so he devised a method that allowed them to, as it were, self-correct." Newton "invented a certain technique known today as linear regression analysis", as he wrote the first of the two 'normal equations' known from ordinary least squares, averaged a set of data, 50 years before Tobias Mayer, the person originally thought to be the oldest to do so, and he also summed the residuals to zero, forcing the regression line through the average point. He differentiated between two uneven sets of data and may have considered an optimal solution regarding bias, although not in terms of effectiveness.

He showed that coloured light does not change its properties by separating out a coloured beam and shining it on various objects, and that regardless of whether reflected, scattered, or transmitted, the light remains the same colour. Thus, he observed that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves. This is known as Newton's theory of colour. His 1672 paper on the nature of white light and colours forms the basis for all work that followed on colour and colour vision.

Philosophiæ Naturalis Principia Mathematica

Newton had been developing his theory of gravitation as far back as 1665. In 1679, he returned to his work on celestial mechanics by considering gravitation and its effect on the orbits of planets with reference to Kepler's laws of planetary motion. Newton's reawakening interest in astronomical matters received further stimulus by the appearance of a comet in the winter of 1680–1681, on which he corresponded with John Flamsteed. After his exchanges with Robert Hooke, Newton worked out a proof that the elliptical form of planetary orbits would result from a centripetal force inversely proportional to the square of the radius vector. He shared his results with Edmond Halley and the Royal Society in De motu corporum in gyrum, a tract written on about nine sheets which was copied into the Royal Society's Register Book in December 1684. As part of this work, Newton also coined the term centripetal force. This tract contained the nucleus that Newton would develop and expand to form the Principia.

The Philosophiæ Naturalis Principia Mathematica was published on 5 July 1687 with encouragement and financial help from Halley. In this work, Newton stated the three universal laws of motion. Together, these laws describe the relationship between any object, the forces acting upon it and the resulting motion, laying the foundation for classical mechanics. They contributed to numerous advances during the Industrial Revolution and were not improved upon for more than 200 years. Many of these advances still underpin non-relativistic technologies today. Newton used the Latin word gravitas (weight) for the effect that would become known as gravity, and formulated the law of universal gravitation. His work achieved the first great unification in physics. He solved the two-body problem, and introduced the three-body problem.

In the same work, Newton presented a calculus-like method of geometrical analysis using 'first and last ratios', gave the first analytical determination (based on Boyle's law) of the speed of sound in air, inferred the oblateness of Earth's spheroidal figure, accounted for the precession of the equinoxes as a result of the Moon's gravitational attraction on the Earth's oblateness, initiated the gravitational study of the irregularities in the motion of the Moon, provided a theory for the determination of the orbits of comets, and much more. Newton's biographer David Brewster reported that the complexity of applying his theory of gravity to the motion of the moon was so great it affected Newton's health: "[H]e was deprived of his appetite and sleep" during his work on the problem in 1692–93, and told the astronomer John Machin that "his head never ached but when he was studying the subject". According to Brewster, Halley also told John Conduitt that when pressed to complete his analysis Newton "always replied that it made his head ache, and kept him awake so often, that he would think of it no more". [Emphasis in original] He provided the first calculation of the age of Earth by experiment, and also described a precursor to the modern wind tunnel.

Other significant work

Newton studied heat and energy flow, formulating an empirical law of cooling which states that the rate at which an object cools is proportional to the temperature difference between the object and its surrounding environment. It was first formulated in 1701, being the first heat transfer formulation and serves as the formal basis of convective heat transfer, later being incorporated by Joseph Fourier into his work.

Newton was the first to observe and qualitatively describe what would much later be formalised as the Magnus effect, nearly two centuries before Heinrich Magnus's experimental studies. In a 1672 text, Newton recounted watching tennis players at Cambridge college and noted how a tennis ball struck obliquely with a spinning motion curved in flight. He explained that the ball's combination of circular and progressive motion caused one side to "press and beat the contiguous air more violently" than the other, thereby producing "a reluctancy and reaction of the air proportionably greater", an astute observation of the pressure differential responsible for lateral deflection.

Philosophy of science

Newton's role as a philosopher was deeply influential, and understanding the philosophical landscape of the late seventeenth and early eighteenth centuries requires recognising his central contributions. Historically, Newton was widely regarded as a core figure in modern philosophy. For example, Johann Jakob Brucker's Historia Critica Philosophiae (1744), considered the first comprehensive modern history of philosophy, prominently positioned Newton as a central philosophical figure. This portrayal notably shaped the perception of modern philosophy among leading Enlightenment intellectuals, including figures such as Denis Diderot, Jean le Rond d'Alembert, and Immanuel Kant.

Starting with the second edition of his Principia, Newton included a final section on science philosophy or method. It was here that he wrote his famous line, in Latin, "hypotheses non fingo", which can be translated as "I don't make hypotheses," (the direct translation of "fingo" is "frame", but in context he was advocating against the use of hypotheses in science).

Newton's rejection of hypotheses ("hypotheses non fingo") emphasised that he refused to speculate on causes not directly supported by phenomena. Harper explains that Newton's experimental philosophy involves clearly distinguishing hypotheses—unverified conjectures—from propositions established through phenomena and generalised by induction. According to Newton, true scientific inquiry requires grounding explanations strictly on observable data rather than speculative reasoning. Thus, for Newton, proposing hypotheses without empirical backing undermines the integrity of experimental philosophy, as hypotheses should serve merely as tentative suggestions subordinate to observational evidence.

Newton contributed to and refined the scientific method. In his work on the properties of light in the 1670s, he showed his rigorous method, which was conducting experiments, taking detailed notes, making measurements, conducting more experiments that grew out of the initial ones, he formulated a theory, created more experiments to test it, and finally described the entire process so other scientists could replicate every step.

In his 1687 Principia, he outlined four rules, which together form the basis of modern science:

Later life

Royal Mint

In the 1690s, Newton wrote a number of religious tracts dealing with the literal and symbolic interpretation of the Bible. A manuscript Newton sent to John Locke in which he disputed the fidelity of 1 John 5:7—the Johannine Comma—and its fidelity to the original manuscripts of the New Testament, remained unpublished until 1785.

Newton was also a member of the Parliament of England for Cambridge University in 1689 and 1701, but according to some accounts his only comments were to complain about a cold draught in the chamber and request that the window be closed. He was, however, noted by the Cambridge diarist Abraham de la Pryme to have rebuked students who were frightening locals by claiming that a house was haunted.

Newton moved to London to take up the post of Warden of the Mint during the reign of King William III in 1696, a position that he had obtained through the patronage of Charles Montagu, 1st Earl of Halifax, then Chancellor of the Exchequer. He took charge of England's great recoining, clashed with Robert Lucas, 3rd Baron Lucas of Shenfield, the Governor of the Tower, and secured the job of deputy comptroller of the temporary Chester branch for Edmond Halley. Newton became perhaps the best-known Master of the Mint upon the death of Thomas Neale in 1699, a position he held for the last 30 years of his life. These appointments were intended as sinecures, but Newton took them seriously. He retired from his Cambridge duties in 1701, and exercised his authority to reform the currency and punish clippers and counterfeiters.

As Warden, and afterwards as Master, of the Royal Mint, Newton estimated that 20 per cent of the coins taken in during the Great Recoinage of 1696 were counterfeit. Counterfeiting was high treason, punishable by the felon being hanged, drawn and quartered. Despite this, convicting even the most flagrant criminals could be extremely difficult, but Newton proved equal to the task.

Disguised as a habitué of bars and taverns, he gathered much of that evidence himself. For all the barriers placed to prosecution, and separating the branches of government, English law still had ancient and formidable customs of authority. Newton had himself made a justice of the peace in all the home counties. A draft letter regarding the matter is included in Newton's personal first edition of Philosophiæ Naturalis Principia Mathematica, which he must have been amending at the time. Then he conducted more than 100 cross-examinations of witnesses, informers, and suspects between June 1698 and Christmas 1699. He successfully prosecuted 28 coiners, including the serial counterfeiter William Chaloner, who was hanged.

Knighthood

In April 1705, Newton was knighted by Queen Anne during a royal visit to Trinity College, Cambridge. The knighthood is likely to have been motivated by political considerations connected with the parliamentary election in May 1705, rather than any recognition of Newton's scientific work or services as Master of the Mint. Newton was the second scientist to be knighted, after Francis Bacon.

As a result of a report written by Newton on 21 September 1717 to the Lords Commissioners of His Majesty's Treasury, the bimetallic relationship between gold coins and silver coins was changed by royal proclamation on 22 December 1717, forbidding the exchange of gold guineas for more than 21 silver shillings. This inadvertently resulted in a silver shortage as silver coins were used to pay for imports, while exports were paid for in gold, effectively moving Britain from the silver standard to its first gold standard. It is a matter of debate as to whether he intended to do this or not. It has been argued that Newton viewed his work at the Mint as a continuation of his alchemical work.

Toward the end of his life, Newton spent some time at Cranbury Park, near Winchester, the country residence of his niece and her husband, though he primarily lived in London. His half-niece, Catherine Barton, served as his hostess in social affairs at his house on Jermyn Street in London. In a surviving letter written in 1700 while she was recovering from smallpox, Newton closed with the phrase "your very loving uncle", expressing familial concern in a manner typical of seventeenth-century epistolary style. The historian Patricia Fara notes that the letter's tone is warm and paternal, including medical advice and attention to her appearance during convalescence, rather than conveying any romantic implication.

Wealth

Newton was an active investor at times, including in the South Sea Company and lost at least £10,000, and plausibly more than £20,000 (£4.4 million in 2020) when it collapsed in the South Sea Bubble around 1720. Since Newton was already rich before the bubble, he still died rich, at estate value around £30,000, the equivalent of nearly £1 billion measured as a share of contemporary GDP, or roughly £6 million by standard inflation measures.

Death

Newton died in his sleep in London on 20 March 1727 (NS 31 March 1727), aged 84. Newton was given a state funeral—the first in England for someone recognized primarily for intellectual achievement. The Lord Chancellor, two dukes, and three earls bore his pall, with most of the Royal Society following. His body lay in state in Westminster Abbey for eight days before burial in the nave. Newton was the first scientist to be buried in the abbey. Voltaire may have been present at his funeral. Newton's death received sizable attention in the contemporary press. Several gazettes announced his death, while The Political State of Great Britain devoted three pages to praising his achievements and described him as "the greatest of Philosophers, and the Glory of the British Nation." Poet James Thomson's "Poem Sacred to the Memory of Sir Isaac Newton" also went through five editions before the end of the year. A bachelor, he had divested much of his estate to relatives during his last years, and died intestate. His papers went to John Conduitt and Catherine Barton.

Shortly after his death, a plaster death mask was moulded of Newton. It was used by the Flemish sculptor John Michael Rysbrack in making a sculpture of Newton. It is now held by the Royal Society.

Newton's hair was posthumously examined and found to contain mercury, probably resulting from his alchemical pursuits. Mercury poisoning could explain Newton's eccentricity in late life.

Personality

Newton has been described as an incredibly driven and disciplined man who dedicated his life to his work. He is known for having a prodigious appetite for work, which he prioritised above his personal health. He maintained strict control over his physical appetites, being sparing with food and drink; contemporary accounts report that he refused to eat rabbits because they were strangled and avoided black pudding because it was made from blood. According to Catherine Conduitt, these choices were motivated by ethical concerns rather than personal taste, with Newton regarding strangling as a cruel method of killing animals and believing that consuming blood encouraged brutality. He has been described as an "incredible polymath" who was "immensely versatile", with some of his first studies relating to a potential phonetic alphabet and universal language. His interests also extended into economics and monetary affairs later in life. As the Master of the Mint, Newton became involved in combating counterfeiting and in matters concerning monetary theory and international currency.

Newton's diverse range of interests is seen in his library, which contained 1,752 books that could be identified. A large portion consisted of works on theology (27.2%, or 477 books), followed by alchemy (9.6%, 169 books), mathematics (7.2%, 126 books), physics (3.0%, 52 books), and finally astronomy (1.9%, 33 books). Ultimately, books related to his famous scientific work made up slightly less than 12% of the total collection.

Although it was claimed that he was once engaged, Newton never married. Voltaire, who was in London at the time of Newton's funeral, said that he "was never sensible to any passion, was not subject to the common frailties of mankind, nor had any commerce with women—a circumstance which was assured me by the physician and surgeon who attended him in his last moments."

Newton had a close friendship with the Swiss mathematician Nicolas Fatio de Duillier, whom he met in London around 1689; some of their correspondence has survived. Their relationship came to an abrupt and unexplained end in 1693, and at the same time Newton suffered a nervous breakdown, which included sending wild accusatory letters to his friends Samuel Pepys and John Locke. His note to the latter included the charge that Locke had endeavoured to "embroil" him with "woemen & by other means".

Newton appeared to be relatively modest about his achievements, writing in a later memoir, "I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." Nonetheless, he could be fiercely competitive and did on occasion hold grudges against his intellectual rivals, not abstaining from personal attacks when it suited him—a common trait found in many of his contemporaries. In a letter to Robert Hooke in February 1675, for instance, he confessed "If I have seen further it is by standing on the shoulders of giants." Some historians argued that this, written at a time when Newton and Hooke were disputing over optical discoveries, was an oblique attack on Hooke who was presumably short and hunchbacked, rather than (or in addition to) a statement of modesty. On the other hand, the widely known proverb about standing on the shoulders of giants, found in the 17th-century poet George Herbert's Jacula Prudentum (1651) among others, had as its main point that "a dwarf on a giant's shoulders sees farther of the two", and so in effect place Newton himself rather than Hooke as the 'dwarf' who saw farther.

Theology

Religious views

Although born into an Anglican family, by his thirties Newton had developed unorthodox beliefs, with historian Stephen Snobelen labelling him a heretic. Despite this, Newton in his time was considered a knowledgeable and insightful theologian who was respected by his contemporaries, with Thomas Tenison, the then Archbishop of Canterbury, telling him "You know more divinity than all of us put together", and the philosopher John Locke describing him as "a very valuable man not onely for his wonderful skill in Mathematicks but in divinity too and his great knowledg in the Scriptures where in I know few his equals". By 1680, his reputation in biblical scholarship was established. John Mill sought his advice on a critical New Testament edition, and the two had a short correspondence on interpreting the early chapters of Genesis as well. Thomas Burnet consulted Newton on drafts of Telluris theoria sacra, and with Henry More he discussed the interpretation of the Apocalypse at Cambridge.

William Stukeley wrote of Newton’s diligence in reading and studying the Bible:No man in England read the Bible more carefully than he did, none study’d it more, as appears by his printed works, by many pieces he left which are not printed, and even by the Bible which he commonly used, thumbd over, as they call it, in an extraordinary degree, with frequency of use.By 1672, he had started to record his theological researches in notebooks which he showed to no one and which have only been available for public examination since 1972. Over half of what Newton wrote concerned theology and alchemy, and most has never been printed. His writings show extensive knowledge of early Church texts and reveal that he sided with Arius, who rejected the conventional view of the Trinity and was the losing party in the conflict with Athanasius over the Creed. Newton "recognized Christ as a divine mediator between God and man, who was subordinate to the Father who created him." He was especially interested in prophecy, but for him, "the great apostasy was trinitarianism."

Newton tried unsuccessfully to obtain one of the two fellowships that exempted the holder from the ordination requirement. At the last moment in 1675, he received a government dispensation that excused him and all future holders of the Lucasian chair.

Worshipping Jesus Christ as God was, in Newton's eyes, idolatry, an act he believed to be the fundamental sin. In 1999, Snobelen wrote, that "Isaac Newton was a heretic. But ... he never made a public declaration of his private faith—which the orthodox would have deemed extremely radical. He hid his faith so well that scholars are still unraveling his personal beliefs." Snobelen concludes that Newton was at least a Socinian sympathiser (he owned and had thoroughly read at least eight Socinian books), possibly an Arian and almost certainly an anti-trinitarian.

Religious thought

Newton and Robert Boyle's approach to mechanical philosophy was promoted by rationalist pamphleteers as a viable alternative to pantheism and enthusiasm. It was accepted hesitantly by orthodox preachers as well as dissident preachers like the latitudinarians. The clarity and simplicity of science was seen as a way to combat the emotional and metaphysical superlatives of both superstitious enthusiasm and the threat of atheism, and at the same time, the second wave of English deists used Newton's discoveries to demonstrate the possibility of a "Natural Religion".

The attacks made against pre-Enlightenment "magical thinking", and the mystical elements of Christianity, were given their foundation with Boyle's mechanical conception of the universe. Newton gave Boyle's ideas their completion through mathematical proofs and, perhaps more importantly, was very successful in popularising them.

Alchemy

Of an estimated ten million words of writing in Newton's papers, about one million deal with alchemy. Many of Newton's writings on alchemy are copies of other manuscripts, with his own annotations. Alchemical texts mix artisanal knowledge with philosophical speculation, often hidden behind layers of wordplay, allegory, and imagery to protect craft secrets. Some of the content contained in Newton's papers could have been considered heretical by the church.

In 1888, after spending sixteen years cataloguing Newton's papers, Cambridge University kept a small number and returned the rest to the Earl of Portsmouth. In 1936, a descendant offered the papers for sale at Sotheby's. The collection was broken up and sold for a total of about £9,000. John Maynard Keynes was one of about three dozen bidders who obtained part of the collection at auction. Keynes went on to reassemble an estimated half of Newton's collection of papers on alchemy before donating his collection to Cambridge University in 1946.

All of Newton's known writings on alchemy are currently being put online in a project undertaken by Indiana University: "The Chymistry of Isaac Newton" and has been summarised in a book.

Newton's fundamental contributions to science include the quantification of gravitational attraction, the discovery that white light is actually a mixture of immutable spectral colors, and the formulation of the calculus. Yet there is another, more mysterious side to Newton that is imperfectly known, a realm of activity that spanned some thirty years of his life, although he kept it largely hidden from his contemporaries and colleagues. We refer to Newton's involvement in the discipline of alchemy, or as it was often called in seventeenth-century England, "chymistry."

In June 2020, two unpublished pages of Newton's notes on Jan Baptist van Helmont's book on plague, De Peste, were being auctioned online by Bonhams. Newton's analysis of this book, which he made in Cambridge while protecting himself from London's 1665–66 epidemic of the bubonic plague, is the most substantial written statement he is known to have made about the plague, according to Bonhams. As far as the therapy is concerned, Newton writes that "the best is a toad suspended by the legs in a chimney for three days, which at last vomited up earth with various insects in it, on to a dish of yellow wax, and shortly after died. Combining powdered toad with the excretions and serum made into lozenges and worn about the affected area drove away the contagion and drew out the poison".

Legacy

Recognition

The mathematician and physicist Joseph-Louis Lagrange frequently asserted that Newton was the greatest genius who ever lived, and once added that Newton was also "the most fortunate, for we cannot find more than once a system of the world to establish." The English poet Alexander Pope wrote the famous epitaph:

Nature, and Nature's laws lay hid in night.

God said, Let Newton be! and all was light.

But this was not allowed to be inscribed in Newton's monument at Westminster. The epitaph added is as follows:

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,

which 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.

Science writer John G. Simmons ranked Newton first in The Scientific 100, based on a qualitative assessment in which he ordered the scientists according to overall influence, and described him as "the most influential figure in the history of Western science". Physicist Peter Rowlands described him as "the central figure in the history of science", who "more than anyone else is the source of our great confidence in the power of science." New Scientist called Newton "the supreme genius and most enigmatic character in the history of science". The philosopher and historian David Hume also declared that Newton was "the greatest and rarest genius that ever arose for the ornament and instruction of the species". In his home of Monticello, Thomas Jefferson, a Founding Father and President of the United States, kept portraits of John Locke, Sir Francis Bacon, and Newton, whom he described as "the three greatest men that have ever lived, without any exception", and who he credited with laying "the foundation of those superstructures which have been raised in the Physical and Moral sciences". The writer and philosopher Voltaire wrote of Newton that "If all the geniuses of the universe were assembled, Newton should lead the band". The neurologist and psychoanalyst Ernest Jones wrote of Newton as "the greatest genius of all times". The mathematician Guillaume de l'Hôpital had a mythical reverence for Newton, which he expressed with a profound question and statement: "Does Mr. Newton eat, or drink, or sleep like other men? I represent him to myself as a celestial genius, entirely disengaged from matter."

Apple story

Newton often told the story that he was inspired to formulate his theory of gravitation by watching the fall of an apple from a tree. The story is believed to have passed into popular knowledge after being related by Catherine Barton, Newton's niece, to Voltaire. Voltaire then wrote in his Essay on Epic Poetry (1727), "Sir Isaac Newton walking in his gardens, had the first thought of his system of gravitation, upon seeing an apple falling from a tree."

Although some question the veracity of the apple story, acquaintances of Newton attribute the story to Newton himself, though not the apocryphal version that the apple actually hit Newton's head. William Stukeley, whose manuscript account of 1752 has been made available by the Royal Society, recorded a conversation with Newton in Kensington on 15 April 1726:

we went into the garden, & drank thea under the shade of some appletrees, only he, & myself. amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. "why should that apple always descend perpendicularly to the ground," thought he to him self: occasion'd by the fall of an apple, as he sat in a comtemplative mood: "why should it not go sideways, or upwards? but constantly to the earths centre? assuredly, the reason is, that the earth draws it. there must be a drawing power in matter. & the sum of the drawing power in the matter of the earth must be in the earths center, not in any side of the earth. therefore dos this apple fall perpendicularly, or toward the center. if matter thus draws matter; it must be in proportion of its quantity. therefore the apple draws the earth, as well as the earth draws the apple."

John Conduitt, Newton's assistant at the Royal Mint and husband of Newton's niece, also described the event when he wrote about Newton's life:

In the year 1666 he retired again from Cambridge to his mother in Lincolnshire. Whilst he was pensively meandering in a garden it came into his thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from earth, but that this power must extend much further than was usually thought. Why not as high as the Moon said he to himself & if so, that must influence her motion & perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that supposition.

Commemorations

Newton's monument (1731) can be seen in Westminster Abbey, at the north of the entrance to the choir against the choir screen, near his tomb. It was executed by the sculptor Michael Rysbrack (1694–1770) in white and grey marble with design by the architect William Kent. The monument features a figure of Newton reclining on top of a sarcophagus, his right elbow resting on several of his great books and his left hand pointing to a scroll with a mathematical design. Above him is a pyramid and a celestial globe showing the signs of the Zodiac and the path of the comet of 1680. A relief panel depicts putti using instruments such as a telescope and prism.

From 1978 until 1988, an image of Newton designed by Harry Ecclestone appeared on Series D £1 banknotes issued by the Bank of England (the last £1 notes to be issued by the Bank of England). Newton was shown on the reverse of the notes holding a book and accompanied by a telescope, a prism and a map of the Solar System.

A statue of Isaac Newton, looking at an apple at his feet, can be seen at the Oxford University Museum of Natural History. A large bronze statue, Newton, after William Blake, by Eduardo Paolozzi, dated 1995 and inspired by William Blake's etching, dominates the piazza of the British Library in London. A bronze statue of Newton was erected in 1858 in the centre of Grantham where he went to school, prominently standing in front of Grantham Guildhall.

The manor house at Woolsthorpe is a Grade I listed building by Historic England through being his birthplace and "where he discovered gravity and developed his theories regarding the refraction of light".

The Institute of Physics, or IOP, has its highest and most prestigious award, the Isaac Newton Medal, named after Newton, which is given for world-leading contributions to physics. It was first awarded in 2008.

The Enlightenment

It is held by European philosophers of the Enlightenment and by historians of the Enlightenment that Newton's publication of the Principia was a turning point in the Scientific Revolution and started the Enlightenment. It was Newton's conception of the universe based upon natural and rationally understandable laws that became one of the seeds for Enlightenment ideology. John Locke and Voltaire applied concepts of natural law to political systems advocating intrinsic rights; the physiocrats and Adam Smith applied natural conceptions of psychology and self-interest to economic systems; and sociologists criticised the current social order for trying to fit history into natural models of progress. James Burnett, Lord Monboddo and Samuel Clarke resisted elements of Newton's work, but eventually rationalised it to conform with their strong religious views of nature.

Works

Published in his lifetime

De analysi per aequationes numero terminorum infinitas (1669, published 1711)

Of Natures Obvious Laws & Processes in Vegetation (unpublished, c. 1671–75)

De motu corporum in gyrum (1684)

Philosophiæ Naturalis Principia Mathematica (1687)

Scala graduum Caloris. Calorum Descriptiones & signa (1701)

Opticks (1704)

Reports as Master of the Mint (1701–1725)

Arithmetica Universalis (1707)

Published posthumously

De mundi systemate (The System of the World) (1728)

Optical Lectures (1728)

The Chronology of Ancient Kingdoms Amended (1728)

Observations on Daniel and The Apocalypse of St. John (1733)

Method of Fluxions (1671, published 1736)

An Historical Account of Two Notable Corruptions of Scripture (1754)