Talk:Isaac Newton/Facts

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Woking verion: Revision as of 14:22, 2 September 2006 diff.

References

• "Newton, Sir Isaac". The Columbia Encyclopedia (6th ed. ed.). New York: Columbia University Press. 2004. {{cite encyclopedia}}: |edition= has extra text (help)
  • no mention of calendar used, but gives 1642 as date of birth
• Bell, E.T. (1986) [1937]. "On the Seashore: Newton". Men of Mathematics (Touchstone ed.). New York: Simon & Schuster.
  • (p. v) "For the principal dates and leading facts in the life of a particular man I have consulted the obituary notices (of the moderns); these are found in the proceedings of the learned societies of which the man in question was a member."
  • (p. v) "It would be rash to claim that every date or spelling of proper names in the book is correct"
  • (p. 90) "...born on Christmas Day ("old style" of dating), 1642,..."
• Cohen, Bernard (2002). "Introduction". The Cambridge Companion to Newton. Cambridge: Cambridge University Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Delambre, M. (1867). "Notice sur la vie et les ouvrages de M. le comte J. L. Lagrange". Oeuvres de Lagrange I. Paris: Secretaire perpetuel de l'Academie des Sciences. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
• Westfall, Richard S. (1983) [1980]. Never at Rest: A Biography of Isaac Newton. New York: Cambridge University Press.
  • (p. xvi) "Everywhere I have given dates as they were to the people involved...where confusion might arise, I have included in parentheses O.S. (Old Style) for the Julian calendar and N.S. (New Style) for the Gregorian."
• Westfall, Richard S. (1994). "Newton, Isaac". Catalog of the Scientific Community in the 16th and 17th Centuries. The Galileo Project. Retrieved 2006-09-11.
  • This is not an independent source, "Source: Richard S. Westfall, Never at Rest, (Cambridge, 1980). I have drawn up this sketch by skimming through my biography to remind myself of details." It is included because Westfall concisely summarizes information available in Never at Rest in an easy to use format.
• White, Michael (1999). Isaac Newton: The Last Sorcerer. Reading, MA: Perseus Books.

Isaac Newton

• Sir Isaac Newton
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• President of the Royal Society
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• birth 4 January 1643
  • (Westfall 1980, p. 40)
• death 31 March 1727
• birth OS: 25 December 1642
  • (Bell 1937, p. 90)
  • (Westfall 1980, p. 40)
• death OS: 20 March 1727
• was English
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Westfall 1994)
• was a mathematician
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Westfall 1994)
• was a physicist
  • "natural philosopher (physicist)" "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Westfall 1994) listed as subordinate scientific discipline
• was an astronomer
• was an alchemist
  • (Wesfall 1994) listed as subordinate scientific discipline, "Newton's long investigation of alchemy is well established from his surviving manuscripts."
• was a natural philosopher
  • "natural philosopher (physicist)" "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • note: (Cohen, Smith 2002, p. 2) calls this historically correct, but seriously misleading. " Newton's Principia is the single work that most effected the divorce of physics, and hence of science generally, from philosophy."
  • (Westfall 1994) listed as subordinate scientific discipline, " Newton always considered himself a natural philosopher, and the central strand of his scientific development consisted of his speculations on the nature of physical reality..."
  • (Westfall 1980, p. 270) "In [Hypothesis], Newton presented himself in his preferred role, not of positive scientist, but of natural philosopher confronting the entire sweep of nature."
• generally regarded as one of the greatest scientists in history
  • "is considered by many the greatest scientist that ever lived." "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• generally regarded as one of the greatest mathematicians in history
• wrote the Philosophiae Naturalis Principia Mathematica
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Cohen, Smith 2002, p. 2)
• in which he described universal gravitation
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• in which he described the three laws of motion
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• laying the groundwork for classical mechanics
• derived Kepler's laws of planetary motion from this system
  • (Bell 1937, p. 109)
• first to show that the motion of objects on Earth and of celestial bodies are governed by the same set of natural laws
• unifying and deterministic power of his laws was integral to the scientific revolution
• unifying and deterministic power of his laws was integral to the advancement of heliocentrism

• Among other scientific discoveries
• spectrum of colours observed when white light passes through a prism
• Roger Bacon claimed spectrum was added by the prisim
• realised spectrum inherent in the white light and not added by the prism
• notably argued that light is composed of particles
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
• developed a law of cooling,
• described the rate of cooling of objects when exposed to air
• enunciated the principles of conservation of momentum
• enunciated the principles of angular momentum
• studied the speed of sound in air
• voiced a theory of the origin of stars
• (Despite this)? renown in mainstream science
• spent more time working on alchemy than physics
  • "spent more of his life intensely involved with alchemy than he had delving into the clear blue waters of pure science." (White 1999, p. 2)
• wrote considerably more papers on the former than the latter

• played a major role in the development of calculus
• (today sharing or shared?) credit with Gottfried Leibniz
• made contributions to other areas of mathematics
• contributed the generalised binomial theorem
• mathematician and mathematical physicist Joseph Louis Lagrange
• birth 1736
• death 1813
• said "Newton was the greatest genius that ever existed and the most fortunate, for we cannot find more than once a system of the world to establish."
  • note: (Delambre 1867, p. xx) "aussi M. Lagrange, qui le citait souvent comme le plus grand génie qui eût jamais existé, ajoutait-il aussitôt: et le plus heureux; on ne trouve qu'une fois un système du monde à établir."

Biography

Early years

• at Woolsthorpe Manor
  • (Westfall 1980, p. 40)
• born in Woolsthorpe-by-Colsterworth
  • (Westfall 1980, p. 40)
• a hamlet in the county of Lincolnshire
  • (Westfall 1980, p. 40)
  • (White 1999, p. 7)
• born prematurely
  • (Bell 1937, p. 90)
  • (Westfall 1980, p. 48) "apparently premature"
  • note: (White 1999, p. 11) tries to cast doubt on this
• no one expected him to live
  • (Westfall 1980, p. 48)
  • note: (White 1999, p. 12) calls this "part of the legend"
• mother Hannah Ayscough
  • (Bell 1937, p. 90)
  • (Westfall 1980, p. 44) "Hannah Ayscough (or Askew)"
  • (White 1999, p. 9) "Hannah took the name Ayscough-Newton."
• his mother is reported to have said that his body at that time could have fit inside a quart mug
  • (Bell 1937, p. 90) "His mother said he was so undersized at birth that a quart mug could easily have contained all there was of him"
  • (Westfall 1980, p. 49) "S^r I. N. told me that he had been told that when he was born he was so little they could put him into a quart pot..."
  • (White 1999, pp. 11-12) "'Sir I. N. told me', [John] Conduitt recalled, 'that he had been told that when he was born he was so little they could put him into a quart pot"
• father also named Isaac
  • (Bell 1937, p. 90)
  • (Westfall 1980, p. 44)
  • (White 1999, p. 8)
• had been a farmer
  • (Westfall 1994) "was a yeoman farmer, who might perhaps be called gentry since he was the lord of a minor manor. The background of the family was yeoman, however,..."
  • (White 1999, p. 11)
• had died three months before Newton's birth
  • (Westfall 1980, p.47) "early in October, 1642"
  • (Westfall 1980, p. 48)
  • (White 1999, p. 10) "a few days before the battle of Edgehill"
• at the time of the English Civil War
  • (Westfall 1980, p.49)
• when two his mother remarried and went to live with her new husband
  • note: (Bell 1937, p. 91) "Mrs. Smith left her three-year-old son"
  • note: (Westfall 1980, p. 49) "immediately following his third birthday"
  • note: (White 1999, p. 16) gives 1646-01-27 and states Isaac was three
• left her son in the care of his maternal grandmother, Margery Ayscough
  • (Bell 1937, p. 91) "to the care of his grandmother"
  • (Westfall 1980, p. 53) "left in Woolsthorpe with his grandmother Ayscough"
  • (White 1999, p. 18) "in the care of his grandparents, James and Margery Ayscough"
• According to E.T. Bell (1937, Simon and Schuster) and H. Eves:

Newton began his schooling in the village schools and was later sent to The King's School, Grantham, where he became the top boy in the school. At Kings he lodged with the local apothecary, William Clarke and eventually became engaged to the apothecary's stepdaughter, Anne Storer, before he went off to Cambridge University at the age of 19. As Newton became engrossed in his studies, the romance cooled and Miss Storer married someone else. It is said he kept a warm memory of this love, but Newton had no other recorded "sweethearts" and never married.

• • note: (Bell 1937, pp. 91-2)

    The earliest part of Newton's education was received in the common village schools of his vicinity...quickly rose to the distinction of top boy in the school...While at the The King's School, Grantham, and subsequently while preparing for Cambridge, Newton lodged with a Mr. Clarke, the village apothecary...Clarke's stepdaughter, Miss Storey with whom he fell in love and to whom he became engaged before leaving Woolsthorpe for Cambridge in June, 1661, at the age of nineteen...absence and growing absorption in his work thrust romance into the background...Miss Storey became Mrs. Vincent.

• Bell and Eves' sources for this claim are William Stukeley and Mrs Vincent
  • note: (Bell 1937) does not mention any sources
• Mrs Vincent (the former Miss Storer--actually named Katherine, not Anne)
• merely say that Newton entertained "a passion" for Storer while he lodged at the Clarke house.

• from the age of about twelve until seventeen was educated at The King's School,Grantham
  • note: (Westfall 1980, p. 55) "Free Grammar School of King Edward VI of Grantham"
  • note: (Westfall 1980, footnote 39, p. 56) mentions "considerable disagreement among biographers over the chronology of Newton's period in Grantham" but accepts: "By Newton's own testimony, he entered the school in Grantham when he was twelve" with reservations

    Newton was at Grantham initially four and a half years...He returned to Woolsthorpe for three-quarters of a year, and then came back to Grantham for three-quarters of a year...Projecting backwards from his admission to Trinity, he came back to Grantham about the beginning of September 1660; he returned to Woolsthorpe earlier, about the beginning of December 1659; and he went originally to Grantham in the late spring of 1655. Perhaps all of these dates should be set back by some indeterminate but necessarily fairly short interval to allow for a pause in Woolsthorpe between grammar school and the university, although there is no mention of such. There is evidence that we must set the dates back a bit over a month at the least. On 28 Oct. 1659, Newton was fined...and must therefore have been called home from school before the beginning of December.

• signature can still be seen upon a library window sill
  • (Westfall 1980, p. 60) "a stone windowsill still bears one of his signatures" (no mention of library)
• was removed from school
  • (Westfall 1980, p. 63) "late 1659"
  • (White 1999, p. 25) "late 1658"
• by Oct 1659 was to be found at Woolsthorpe
  • (Westfall 1980, p. 63) "records on the manor court of Colsterworth show that on 28 October 1659 Newton was fined..."
  • (White 1999, p. 25) "most of 1659 Isaac lived at the manor"
• mother attempted to make a farmer of him at Woolsthorpe
  • (Westfall 1980, p. 63) "face the realities of life and learn to manage his estate"
  • (White 1999, p. 25) "She saw little need for her son to be educated; her husband had demonstrated how the farm could be managed even without the benefit of literacy."
  • note: (Westfall 1980, footnote 20, p. 73) claims that Hannah Smith's household at this time was very wealthy, perhaps in the top 1500 of England, "make a farmer of him" may misrepresent things
• by later reports of his contemporaries,he was thoroughly unhappy with the work
  • (Westfall 1980, p. 63)
  • (White 1999, p. 25-7)
• Henry Stokes, master at the King's School
  • (Westfall 1980, p. 55)
  • (White 1999, p. 19)
• it appears to be Stokes who persuaded his mother to send him back to school so that he might complete his education.
  • note: (Westfall 1980, p. 64) mentions Ayscough but states: "Mr. Stokes, was if anything more insistent"
  • note: (White 1999, p. 27-8) also mentions William Ayscough and Humphrey Babington.
• completed education at the age of eighteen
• achieved an admirable final report
• His teacher said:

  His genius now begins to mount upwards apace and shine out with more strength. He excels particularly in making verses. In everything he undertakes, he discovers an application equal to the pregnancy of his parts and exceeds even the most sanguine expectations I have conceived of him.

  • note: (Westfall 1980, p. 65) attributes an almost identical quote to John Conduitt citing Keynes MS 130.2, p. 32-33
• matriculated to Trinity College, Cambridge June 1661
  • (Bell 1937, p. 96) "In June, 1661 Newton entered Trinity College, Cambridge..."
  • note: (Westfall 1980, p. 66-7) admitted Trinity College in June, matriculated to the University 8 July
  • (Westfall 1980, p. 86) "admitted to Trinity on 5 June 1661"
• at that time, the college's teachings were based on those of Aristotle
  • "focus centered on Aristotle" (Westfall 1980, p. 81-2)
• preferred to read the more advanced ideas of modern philosophers
• preferred to read Descartes
  • (Westfall 1980, p. 89)
• Descartes was a modern philospher
• preferred to read the more advanded ideas of astronomers
• preferred to read Galileo
• preferred to read Copernicus
• preferred to read Kepler
• discovered the generalised binomial theorem, 1665
  • (Bell 1937, p. 97) "His discovery of the binomial theorem...preceded this [manuscript dated 20 May 1665]"
  • note: (Bell 1937, p. 97-8) "A proof of the binomial theorem...came only in the nineteenth century, we need merely state here that...Newton satisfied himself that the theorem was correct for such values of a,b as he had occasion to consider in his work."
  • note: (Westfall 1980, p. 140) "...he assigned the binomial expansion to the winter between 1664 and 1665."
  • note: (Westfall 1980, p. 118) "It did not seriously occur to him that the principle of continuity on which he relied might betray him. Later he would recognize how flimsy the foundation was, and he would place the binomial expansion on a firmer footing."
• began to develop a mathematical theory that would later become calculus, 1665
  • (Bell 1937, p. 96) "three years 1664-66...he laid the foundation of all his subsequent work in scienc and mathematics"
  • (Westfall 1980, p. 114) "first important step beyond his mentors, which he dated on several occasions to the winter of 1664-5"
• obtained degree, 1665
  • note: (Bell 1937, p. 97) "took his B.A. degreee in January 1664"
  • (Westfall 1980, p. 86)
• the University closed down as a precaution against the Great Plague soon after
  • (Bell 1937, p. 97) "The Great Plague...of 1664-65, with its milder recurrence the following year...The University was closed, and for the better part of two years Newton retired to meditate at Woolsthorpe."
  • (Westfall 1980, p. 87) "In the summer of 1665, the university disperesed for most of two years"
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.) "most important discoveries were made during the two-year period from 1664 to 1666, when the university was closed" note: conflicts with article's "18 mo." and "soon after" 1665
  • (Westfall 1980, pp. 141-2) plague visited Cambridge for 2 years beginning summer 1665, city prohibited public meetings 1 September, university dicontinued exercises in the public schools 10 October, Trinity had made argements for absent residents 7 August but many had already left
• for the next 18 months he worked at home on calculus
  • (Bell 1937, p. 97) "In these two years he invented the method of fluxions"
  • note: (Westfall 1980, p. 142) Newton left Cambridge prior to 7 August, returned 20 March 1666, left again probably in June, returned late April 1667
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Westfall 1980, pp. 114-34) describes mathematical work from "winter of 1664-5, or sometime near then" to 13 November 1665
  • (Westfall 1980, pp. 135-9) describes the 14 May, 16 May, and October 1666 tracts
  • (Westfall 1980, p. 139) "His great period of mathematical creativity"
  • (Westall 1980, p. 144) concentrated on matematics nearly exclusively till about the beginning of 1666, returned to it briefly in May and again in October, then "did not touch mathematics at all" for the next two years.
• for the next 18 months he worked at home on optics
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Bell 1937, p. 97) "In these two years he...proved experimentally that white light is composed of light of all the colors"
  • note: (Westfall 1980, pp. 156-8) "the chronology of his optical research is confused." one account by Newton was that he "had the Theory of Colours" in Jnauary 1666, another that the plague years interrupted his optics work at Cambridge, Westfall states: "No resolution of the discrepancies is entirely satisfactory."
• for the next 18 months he worked at home on law of gravitation
  • "Newton, Sir Isaac", The Columbia Encyclopedia (6th ed.)
  • (Bell 1937, p. 97) "In these two years he...discovered the law of universal gravitation"
  • (Westfall 1980, p. 150) mentions measurment of g via pendulum but gives no clear date
  • (Westfall 1980, pp. 151-2) "in a paper which appears to date from the years immediately following his undergraduate career...Here was the inverse-square relation resting squarely on Kepler's third law"
  • (Westfall 1980, p. 155) "Universal gravitation did not yield to Newton at his first effort...spoke only of tendencies to recede...attraction at a distance was inadmissible...Nevertheless, Newton must have had something in mind when he compared the moon's centrifugal force with gravity..."
  • note: (Westfall 1980, pp. 151-5) somewhat downplays the work on gravity at this time, and especially "the notion that universal gravitation appeared to Newton in a flash of insight in 1666", that story Westfall says, "does not survive comparison with the record of his early work in mechanics"
  • note: (Westfall 1980, pp. 145-55) describes work on mechanics during this period
• often did not share concepts he had discovered unless he was asked
• formulated calculus 30 years before he told anyone else about it
  • note: (Westfall 1980, p. 202) "In 1669, events focused Newton's attention once more on his fluxional method...Though he did not then publish it, at least he made it known."
  • note: (Westfall 1980, p. 204) "[De analysi] did contrive to indicate something of the scope of the general method of fluxions."
  • "never tried to publish the tract of October 1666" (Westfall 1980, p. 138)

Middle years

Mathematical research

• Newton became a fellow of Trinity College in 1669.
  • note: (Bell 1937, p. 106) "elected fellow of Trinity in 1667"
  • note: (Westfall 1980, p. 179) "In October 1667, he became only a minor fellow of the college, but advancement to the status of major fellow would follow automatically when he was created Master of Arts nine months hence."
  • note: (Westfall 1980, p. 179) "Shortly after one o'clock on 2 October 1667, Newton became a fellow of the College of the Holy and Undivided Trinity..."
• In the same year he circulated his findings in De Analysi per Aequationes Numeri Terminorum Infinitas (On Analysis by Infinite Series),
  • note: (Westfall 1980, p. 202) De analysi per aequationes numero terminorum infinitas
  • (Westfall 1980, p. 202) About ten days later than late July 1669
  • note: (Westfall 1980, p. 202-6) gave paper to Isaac Barrow for transmission to John Collins, it was Collins who circulated De analysi, "[Newton] was suprised to learn just how widely the paper had been circulated"
  • note: (Westfall 1980, p. 204-5) describes the scope of De analysi, "concerned itself primarily with infinite series in the application to quadratures"
• and later in De methodis serierum et fluxionum (On the Methods of Series and Fluxions),
  • note: (Westfall 1980, p. 231-2) "the most remarkable thing about De methodis with its associated papers is the fact that Newton never completed it...an initial effort which came to a halt, a renewed attempt which advanced a bit further, and ultimate abandonment...Collins newver saw anything of the major treatise beyond the barest of tantalizing hints in a couple of letters."
  • note: (Westfall 1980, p. 226) "known as the Tractatus de methodis serierum et fluxionum (A Treatise of the Methods of Series and Fluxions), though Newton himself did not give it a title"
  • (Westfall 1980, p. 400) "Early in 1685, another Scot, John Craig came to Cambridge to meet him...allowed Craig to read De methodis..."
• whose title gave rise to the "method of fluxions".
  • note: (Bell 1937, p. 97) "He called his method 'fluxions'—from the idea of 'flowing' or variable quantities and their rates of 'flow' or 'growth'." describing a manuscript dated 20 May 1665
  • note: (Westfall 1980, p. 133) "From the idea of motion he derived the term 'fluxional'" describing a 13 November 1665 paper.
  • note: (Westfall 1980, p. 226) "Newton himself did not give it a title"

• Newton and Gottfried Leibniz developed the calculus independently,
  • (Westfall 1980, p. 261) "Building on his own earlier progress, Leibniz achieved the fundamental insights of his differential calculus..."
  • (Westfall 1980, p. 266) "In effect, Leibniz had arrived where Newton had been ten years earlier. He had just invented the calculus."
• using different notations.
  • (Westfall 1980, p. 261) "[Leibniz] developed his distinctive notation, in which the calculus still expresses itself..."
• Although Newton had worked out his method years before Leibniz,
  • (Westfall 1980, p. 266)
• he published almost nothing about it until 1693,
• and did not give a full account until 1704.
• Meanwhile, Leibniz began publishing a full account of his methods in 1684.
• Moreover, Leibniz's notation and "differential Method" were universally adopted on the Continent,
• and after 1820 or so, in the British Empire.
• Newton claimed that he had been reluctant to publish his calculus because he feared being mocked for it.
• Starting in 1699, other members of the Royal Society accused Leibniz of plagiarism,
• and the dispute broke out in full force in 1711.
• Thus began the bitter calculus priority dispute with Leibniz,
  • (Westfall 1980, p. 267) "Newton eventually harvested the bitter fruit his own neuroses had planted. He forced Leibniz to share it with him."
• which marred the lives of both Newton and Leibniz until the latter's death in 1716.
• This dispute created a divide between British and Continental mathematicians
• that may have retarded the progress of British mathematics by at least a century.

• Newton is generally credited with the generalised binomial theorem,
• valid for any exponent.
• He discovered Newton's identities,
• Newton's method,
• classified cubic plane curves (polynomials of degree three in two variables),
• made substantial contributions to the theory of finite differences,
• and was the first to use fractional indices and to employ coordinate geometry to derive solutions to Diophantine equations.
• He approximated partial sums of the harmonic series by logarithms (a precursor to Euler's summation formula),
• and was the first to use power series with confidence and to revert power series.
• He also discovered a new formula for pi.

• He was elected Lucasian Professor of Mathematics in 1669.
  • (Bell 1937, p. 106) "in 1669...succeeded Barrow as Lucasian Professor of Mathematics."
  • note: (Westfall 1980, p. 206-7) Newton was appointed by two executors of Henry Lucas
• In that day, any fellow of Cambridge or Oxford had to be an ordained Anglican priest.
  • note: (Westfall 1980, p. 179) "The incumbents of two specific fellowships excepted, the sixty fellows of the college were required to take holy orders in the Anglican church within seven years of incepting M.A."
• However, the terms of the Lucasian professorship required that the holder not be active in the church
  • note: (Westfall 1980, p. 207) "allowed them to hold ecclesiastical appointments that did not entail cure of souls."
• (presumably so as to have more time for science).
• Newton argued that this should exempt him from the ordination requirement,
• and Charles II, whose permission was needed, accepted this argument.
• Thus a conflict between Newton's religious views and Anglican orthodoxy was averted.

Optics

• From 1670 to 1672 he lectured on optics
  • (Westfall 1980, p. 211) "He delivered a course of lectures in the Lent term of 1670...As the topic for his first course of lectures, Newton chose...optics"
  • (Westfall 1980, p. 252) "As far as we know, Newton completed his lectures on optics in the autumn of 1672..."
  • note: (Westfall 1980, pp. 208-211) describes the record of Newton's teaching to 1687, at Cambridge lectures had given way to tutoring, as Westfall put it "there were the weekly lectures. Or perhaps there were the weekly lectures...In all, he eventually deposited four manuscripts that purported to contain annual courses of lectures through 1687. Questions have been raised about all four, so that it is quite impossible to know for sure on what he lectured."
  • (Westfall 1980, p. 212) "there is reason to think that Newton had resumed his investigation of colors before his appointment, and that he chose to lecture on the topic then foremost in his mind."
• During this period he investigated the refraction of light,
  • note: (Westfall 1980, pp. 212-3) Newton resumed his investigations before 1670, "accounts recored the purchase of three prisms some time after February 1668...His earliest surviving letter, dated 23 February 1669, described his first reflecting telescope and referred obliquely to his theory of colors...As he clarified the theory in 1669..."
  • note: (Westfall 1980, pp. 213-4) dates Newton's experimentum crucis to 1669
• demonstrating that a prism could decompose white light into a spectrum of colours,
• and that a lens and a second prism could recompose the multicoloured spectrum into white light.
• He also showed that the coloured light does not change its properties,
• by separating out a coloured beam and shining it on various objects.
• Newton noted that regardless of whether it was reflected or scattered or transmitted, it stayed the same colour.
• Thus the colours we observe are the result of how objects interact with the incident already-coloured light, not the result of objects generating the colour.
• Many of his findings in this field were criticized by later theorists,
• the most well-known being Johann Wolfgang von Goethe,
• who postulated his own colour theories.

• From this work he concluded that any refracting telescope would suffer from the dispersion of light into colours,
• and invented a reflecting telescope (today known as a Newtonian telescope) to bypass that problem.
• By grinding his own mirrors, using Newton's rings to judge the quality of the optics for his telescopes,
• he was able to produce a superior instrument to the refracting telescope,
• due primarily to the wider diameter of the mirror.
• (Only later, as glasses with a variety of refractive properties became available, did achromatic lenses for refractors become feasible.)
• In 1671 the Royal Society asked for a demonstration of his reflecting telescope.
  • (Westfall 1980, p. 234) "asked to see it late in 1671. At the very end of the year, Barrow delivered it to them."
• Their interest encouraged him to publish his notes On Colour,
  • (Westfall 1980, p. 234-40) describes the paper on colors
  • note: (Westfall 1980, p. 239) Newton agreed to Society publishing in Philosophical Transactions
  • note: (Westfall 1980, p. 238) paper was "in the form of a letter addressed to Henry Oldenburg", Westfall never mentions a title as presented to the Society or published in Philosophical Transactions
  • note: (Westfall 1980, p. 238) Newton had already been revising his lectures for publication, at Barrow's behest
• which he later expanded into his Opticks.
  • (Westfall 1980, p. 239) "...his Opticks, finally published in 1704, merely restated conclusions worked out int the late 1660's..."
• When Robert Hooke criticised some of Newton's ideas,
  • (Westfall 1980, p. 241) "...within two weeks he received a lengthy critique from Robert Hooke...a condescending comentary...denied the conclusions Newton drew..."
• Newton was so offended that he withdrew from public debate.
  • note:(Westfall 1980, p. 241) "Initially, Newton chose to ignore Hooke's tone"
  • note:(Westfall 1980, p. 247) "Hooke was not the sole cause of Newton's exasperation."
  • (Westfall 1980, p. 252) "...for the moment, a modicum of criticism had sufficed, first to incite him to rage, and then to drive him into isolation."
  • (Westfall 1980, p. 279) "With that [letter of May 1678 telling Aubrey not to send anymore corespondence from Anthony Lucas] he brought his correspondence about colors to an end...As far as he could, he isolated himself. To the best of our knowledge he wrote only two letters...between June 1678 and December 1679"
  • note: (Westfall 1980, pp. 238-80) details critisism of others besides Hooke 1672-1678
• The two men remained enemies until Hooke's death.
  • (Westfall 1980, p. 247) "Newton's reply was viciously insulting—a paper filled with hatred and rage. It established a pattern for his relations with Hooke that was never broken."

• In one experiment, to prove that colour perception is caused by pressure on the eye, Newton slid a darning needle around the side of his eye until he could poke at its rear side,
• dispassionately noting "white, darke & coloured circles" so long as he kept stirring with "y^e bodkin."

• Newton argued that light is composed of particles,
• but he had to associate them with waves to explain the diffraction of light (Opticks Bk. II, Props. XII-L).
• Later physicists instead favoured a purely wavelike explanation of light to account for diffraction. *Today's quantum mechanics restores the idea of "wave-particle duality",
• although photons bear very little resemblance to Newton's corpuscles (e.g., corpuscles refracted by accelerating toward the denser medium).

• Newton is believed to have been the first to explain precisely the formation of the rainbow from water droplets dispersed in the atmosphere in a rain shower.
• Figure 15 of Part II of Book One of the Opticks shows a perfect illustration of how this occurs.

• In his Hypothesis of Light of 1675,
  • note: (Westfall 1980, p. 269) "An Hypothesis explaining the Properties of Light discoursed of in my severall Papers" though Westfall later gives: "Hypothesis of Light"
  • (Westfall 1980, p. 268-9) sent to Oldenburg 7 December 1675 "Discourse of Observations" and "Hypothesis of Light"
  • note: (Westfall 1980, p. 269) "In many respects, the "Hypothesis of Light" was also not new. He had begun to draft it in 1672 as part of his reply to Hooke, and things like it had appeared already in his essay "Of Colours" in 1666"
• Newton posited the existence of the ether
  • (Westfall 1980, pp. 270-1)
• to transmit forces between particles.
  • (Westfall 1980, p. 270) "a general system of nature based on the same aether."
  • note:(Westfall 1980, pp. 270-1) "All of the crucial phenomena that appeared in his "Quaestiones" a decade earlier appeared now in the "Hypothesis" either to be explained by aetherial mechanisms or to offer illustrative analogies." Westfall mentions: cohesion of bodies, surface tension, static electricity, and notably gravity; however "transmit forces between particles" may be taking the description a bit far
• Newton was in contact with Henry More,
• the Cambridge Platonist
  • (Westfall 1980, p. 301)
• who was born in Grantham,
  • (Westfall 1980, p. 349)
• on alchemy,
  • note: (Westfall 1980, pp. 348-9) "Although much has been written about the influence of More on Newton, and much speculated on the basis of their common origin in Grantham, concerning their mutual contact in Cambridge, we know very little that is concrete about their relations."
• and now his interest in the subject revived.
  • note: When?
• He replaced the ether with occult forces based on Hermetic ideas of attraction and repulsion between particles.
• John Maynard Keynes, who acquired many of Newton's writings on alchemy,
• stated that "Newton was not the first of the age of reason: he was the last of the magicians."
  • Keynes, John Maynard (1972). ""Newton, The Man"". The Collected Writings of John Maynard Keynes Volume X. pp. pp. 363-4. {{cite book}}: |pages= has extra text (help); Unknown parameter |publiser= ignored (|publisher= suggested) (help)
• Newton's interest in alchemy cannot be isolated from his contributions to science.
• (This was at a time when there was no clear distinction between alchemy and science.)
• Had he not relied on the occult idea of action at a distance, across a vacuum,
• he might not have developed his theory of gravity. (See also Isaac Newton's occult studies.)
  • (Westfall 1980, p. 390) "As it appears to me, Newton's philosophy of nature underwent a profound conversion in 1679-80 under the combined influence of alchemy and the cosmic problem of orbital mechanics, two unlikely partners which made common cause on the issue of action at a distance."

• In 1704 Newton wrote Opticks,
• in which he expounded his corpuscular theory of light.
• He considered light to be made up of extremely subtle corpuscles,
• that ordinary matter was made of grosser corpuscles
• and speculated that through a kind of alchemical transmutation "Are not gross Bodies and Light convertible into one another,...and may not Bodies receive much of their Activity from the Particles of Light which enter their Composition?"
  • Dobbs, J.T. (1982). "Newton's Alchemy and His Theory of Matter". Isis. 73 (4): p. 523. {{cite journal}}: |pages= has extra text (help); Unknown parameter |month= ignored (help) quoting Opticks
• Newton also constructed a primitive form of a frictional electrostatic generator,
• using a glass globe (Optics, 8th Query).

Gravity and motion

• In 1679, Newton returned to his work on mechanics, i.e., gravitation and its effect on the orbits of planets,
  • (Westfall 1980, pp. 382-8) describes the correspondence w/ Hooke beginning late in 1679
  • (Westfall 1980, p. 387) "Whether it was Hooke's explicit proposal or the one implicit in the whole conversation that moved him, Newton later acknowleged that he took up the challenge."
  • (Westfall 1980, p. 388) "the demonstration, which probably dated from early 1680, was one of the two foundation stones on which the concept of universal gravitation rested"
  • note: (Westfall 1980, pp. 382-8) this was a brief period of work, a hasty response to Hooke in 1679, another reply accepting Hooke's correction, then the 1680 investigation. Westfall states: "Newton did not even consider sending [the 1680 demonstration] to Hooke. Neither, in 1680, did he pursue it any further himself. He had worn out his affection for philosophy and now devoted his time to other studies..."
• with reference to Kepler's laws of motion,
  • (Westfall 1980, p. 387) "In [the 1680 demonstration], Newton began...by demonstrating Kepler's law of areas. Using the law of areas and accepting Hooke's definition of the dynamic elements of orbital motion, he showed first that the force varies inversely as the square of the distance..."
  • (Westfall 1980, p. 405) "Under Hooke's stimulus, he had extended the inverse-square force to account for Kepler's first law."
• and consulting with Hooke and Flamsteed on the subject.
  • note: (Westfall 1980, p. 382) Hooke asked for Newton's opinion on his hypothesis that planetary motions are a composition of tangential motion and an attrative motion towards the center; (p. 383) Newton declined but did suggest an experiment to test diurnal rotation; (p. 384-5) Hooke corrected a mistake of Newton's concerning the path of a body falling toward a rotating earth; (p. 385-6) Newton accepts the correction, shows the path of a body falling under uniform gravity, and briefly mentions how the orbit might vary if gravity were not constant; (p. 386) Hooke again corrects Newton and mentions the inverse-square relation, Westfall says of Hooke's response: "On close analysis, its apparent derivation of the inverse-square law turns out to be a bastard demonstartion resting on a deep confustion about dynaics and accelerated motion.", (p. 388) "Newton did not even consider sending [the 1680 demonstration] to Hooke."
  • note: (Westfall 1980, p. 383) Hooke remarked about an observation by Flamsteed which led to Newton's suggested experiment to demonstrate diurnal rotation, but there is no mention of any direct correspondence (with Flamsteed)
  • note: (Westfall 1980, p. 408-9) detail the correspondence w/ Flamsteed after De Motu had been give to Halley
• He published his results in De Motu Corporum (1684).
  • (Westfall 1980, pp. 403-3) "In November [1684]...Halley received...a small treatise of nine pages with the title De Motu corporum in gyrum (On the Motion of Bodies in an Orbit).
  • note: (Westfall 1980, pp. 403-4) Westfall does not mention publication of De Motu corporum in gyrum, (p. 423) but Newton expanded the tract into 2 books to which he gave the title De motu corporum (On the Motion of Bodies); Book I was later called Lectiones de motu (Lectures on Motion) and Book II was published after his death as De mundi systemate (On the System of the World).
  • note: (Westfall 1980, p. 403) Newton delayed giving Halley the 1680 demonstration and discovered an error in his earlier calculations; "Not one to give up, he started anew and finally achieved his goal."
  • note: (Westfall 1980, p. 405) the 1680 demonstration "had extended the inverse-square force to account for Kepler's first law" and (p. 387) "Using the law of areas and accepting Hooke's definition of the dynamic elements of orbital motion, he showed first that the force varies inversely as the square of the distance..."; (p. 404) The 1684 De motu demonstrated "that an elliptical orbit entails an inverse-square force to one focus...An inverse-square force entails a conic orbit...demonstrated Kepler's second and third laws as well...hinted at a general science of dynamics by further deriving the trajectory of a projectile throught a resisting medium."
  • note: (Westfall 1980, p. 404) De Motu was not the end result of a period of work as the article text implies, but rather a beginning, "The problem had seized Newton and would not let him go." (p. 407) "...he had completed nothing. By 1684 he had littered his study with unfinished mathematical treatises...The period 1684-7 brought an end to the tentative years...this time the sheer grandeur of the theme carried him through to completion."
• This contained the beginnings of the laws of motion that would inform the Principia.
  • (Westfall 1980, p. 404) "Starting from postulated principles of dynamics, the treatise demonstrated..."
  • (Westfall 1980, p. 405) "Initially the treatise contained four theorems and five problems that dealt whith motion..."
  • note:(Westfall 1980, p. 411) "One cannont stress too much the crudity of the dynamic foundation on which the brilliant structure of De motu rested."
  • note:(Westfall 1980, pp. 411-3) Newton used three concepts of force to examine circular motion, discrete impules (f=Δmv), continuous forces producing uniform acceleration (f=ma), and an inherent force maintaining uniform velocity (f=mv), Westfall states: "Newton could not have built the Principia on a foundation so uncertain."
  • (Westfall 1980, 413-4) There are three surviving versions of De Motu, the first registered w/ the Society, the second a copy of the first by Halley, "The third version, on the other hand, contained the beginning of Newton's reconstruction of his dynamics."
  • (Westfall 1980, p. 415) "In two papers of revisions that followed that third version of De motu, Newton completed the transformation of his dynamics into its ultimate form."
  • note:(Westfall 1980, p. 417) "He had seized on the essence of his second law twenty years before and had never altered it as he wrestled with the first law."
• The Philosophiae Naturalis Principia Mathematica
• (now known as the Principia)
• was published on 5 July, 1687
• with encouragement and financial help from Edmond Halley.
  • (Westfall 1980, p. 405) "In August 1684, Halley evoked the same splendor anew, and this time Newton surrendered utterly to its allure. Halley later liked to say that he had been 'the Ulysses who produced this Achilles,' but Halley in London did not understand what was happening in Cambridge. Halley did not extract the Principia from a reluctant Newton. He merely raised a question at a time when Newton was receptive to it."
  • (Westfall 1980, p. 445) "Increasingly anxious that Newton should have some response, Halley apparently seized the initiative and raised the question [publication of Principia] at the society's meeting on 19 May...If the resolution was indeed Halley's work, he took a considerable risk in promoting it."
• In this work Newton stated the three universal laws of motion
• that were not to be improved upon for more than two hundred years.
• He used the Latin word gravitas (weight) for the force that would become known as gravity,
• and defined the law of universal gravitation.
• In the same work he presented the first analytical determination, based on Boyle's law, of the speed of sound in air.

• With the Principia, Newton became internationally recognised.
• He acquired a circle of admirers,
• including the Swiss-born mathematician Nicolas Fatio de Duillier,
• with whom he formed an intense relationship
• that lasted until 1693.
• The end of this friendship led Newton to a nervous breakdown.