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SIR ISAAC NEWTON (1642-1727)

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Originally appearing in Volume V19, Page 588 of the 1911 Encyclopedia Britannica.
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SIR See also:ISAAC See also:NEWTON (1642-1727)  , See also:English natural philosopher, was See also:born on the 25th of See also:December 1642 (o.s.), at Woolsthorpe, a See also:hamlet in the See also:parish of Colsterworth, See also:Lincolnshire, about 6 m. from See also:Grantham . His See also:father (also See also:Isaac See also:Newton) who farmed a small See also:freehold See also:property of his own, died before his son's See also:birth, a few months after his See also:marriage to Hannah See also:Ayscough, a daughter of See also:James Ayscough of See also:Market-Overton . When Newton was little more than two years old his See also:mother married See also:Barnabas See also:Smith, See also:rector of See also:North See also:Witham . Of this marriage there was issue, See also:Benjamin, See also:Mary and Hannah Smith, and to their See also:children See also:Sir Isaac Newton subsequently See also:left the greater See also:part of his property . After having acquired the rudiments of See also:education at two small See also:schools in hamlets See also:close to Woolsthorpe, Newton was sent at the See also:age of twelve to the See also:grammar school of Grantham . While attending Grantham school Newton lived in the See also:house of Mr See also:Clark, an See also:apothecary of that See also:town . According to his own See also:confession he was far from industrious, and stood very See also:low in his class . An unprovoked attack from the boy next above him led to a fight, in which Newton's See also:pluck gave him the victory . This success seems to have led him to greater exertions, and he See also:rose to be the See also:head boy of the school . He displayed very See also:early a See also:taste and an aptitude for See also:mechanical contrivances . He made windmills, See also:water-clocks, kites and dials, and he is said to have invented a four-wheeled See also:carriage which was to be moved by the rider . In 1656 Mr Smith died, and Newton's mother came back with her three children to Woolsthorpe .

Newton was then in his fifteenth See also:

year, and, as his mother in all See also:probability intended him to be a See also:farmer, he was taken away from school . He was frequently sent on market days to Grantham with an old and trusty servant, who made all the purchases, while Newton spent his See also:time among the books in Mr Clark's house . It soon became apparent to Newton's relatives that they were making a See also:great See also:mistake in attempting to turn him into a farmer, and he was therefore sent back again to school at Grantham . His mother's See also:brother, See also:William Ayscough, the rector of See also:Burton Coggles, the next parish, was a See also:graduate of Trinity See also:College; See also:Cambridge, and when he found that Newton's mind was wholly devoted to mechanical and mathematical problems, he urged upon Mrs Smith the desirability of sending her son to his own college . He was accordingly admitted a member of Trinity College on the 5th of See also:June 1661, as a subsizar, and was matriculated on the 8th of See also:July . We have scarcely any See also:information as to his attainments when he commenced See also:residence, and very little as to his studies as an undergraduate . It is known that while still at Woolsthorpe See also:Sanderson's See also:Logic had been read by him to such purpose that his See also:tutor at Trinity College excused his attendance at a course of lectures on that subject . Newton tells us himself that, when he had See also:purchased a See also:book on See also:astrology at See also:Stourbridge See also:fair, a fair held close to Cambridge, he was unable, on See also:account of his See also:ignorance of See also:trigonometry, to• understand a figure of the heavens which was See also:drawn in this book . He therefore bought an English edition of See also:Euclid with an See also:index of propositions at the end of it, and, having turned to two or three which he thought likely to remove his difficulties, he found them so self-evident that he put aside Euclid " as a trifling book," and applied himself to the study of See also:Descartes's See also:Geometry . It is reported that in his examination for a scholarship at Trinity, to which he was elected on the 28th of See also:April 1664, he was examined in Euclid by Dr Isaac See also:Barrow, who formed a poor See also:opinion of his knowledge, and that in consequence Newton was led to read the Elements again with care, and thereby to See also:form a more favourable estimate of Euclid's merits . The study of Descartes's Geometry seems to have inspired Newton with a love of the subject, and to have introduced him to the higher See also:mathematics . In a small See also:commonplace book, bearing on the seventh See also:page the date of See also:January 1663/1664, there are several articles on angular sections, and the squaring of curves and " crooked lines that may be squared," several calculations about musical notes, geometrical propositions from See also:Francis See also:Vieta and Frans See also:van Schooten, annotations out of See also:Wallis's See also:Arithmetic of Infinities, together with observations on See also:refraction, on the grinding of " spherical optic glasses," on the errors of lensesand the method of rectifying them, and on the extraction of all kinds of roots, particularly those "in affected See also:powers." And in this same commonplace book the following entry made by Newton himself, many years afterwards, gives a further account of the nature of his See also:work during the See also:period when he was an undergraduate: "July 4, 1699.-By consulting an account of my expenses at Cambridge, in the years 1663 and 1664, I find that in the year 1664 a little before See also:Christmas, I, being then See also:Senior Sophister, bought Schooten's Miscellanies and Cartes' Geometry (having read this Geometry and See also:Oughtred's Clavis clean over See also:half a year before), and borrowed Wallis's See also:works, and by consequence made these annotations out of Schooten and Wallis, in See also:winter between the years 1664 and 1665 .

At such time I found the method of See also:

Infinite See also:Series; and in summer 1665, being forced from Cambridge by the See also:plague, I computed the See also:area of the See also:Hyperbola at Boothby, in Lincolnshire, to two and fifty figures by the same method." That Newton must have begun early to make careful observations of natural phenomena is sufficiently testified by the follow- . See also:ing remarks about halos, which appear in his See also:Optics, book ii. part iv. obs . 13: " The like Crowns appear sometimes about the See also:moon; for in the beginning of the Year 1664, See also:February 19th, at See also:night, I saw two such Crowns about her . The See also:Diameter of the first or innermost was about three Degrees, and that of the second about five Degrees and an half . Next about the moon was a Circle of See also:white, and 'next about that the inner See also:Crown, which was of a bluish See also:green within next the white, and of a yellow and red without, and next about these See also:Colours were See also:blue and green on the inside of the Outward Crown, and red on the outside of it . At the same time there appear'd a See also:Halo about 22 Degrees 35' distant from the center of the moon . It was elliptical, and its See also:long Diameter was perpendicular to the See also:Horizon, verging below farthest from the moon." In January 1665 Newton took the degree of B.A . The persons appointed (in See also:conjunction with the proctors, See also:John See also:Slade of Catharine See also:Hall, and Benjamin Pulleyn of Trinity College, Newton's tutor) to examine the questionists were John See also:Eachard of Catharine Hall and See also:Thomas Gipps of Trinity College . It is a curious See also:accident that we have no information about the respective merits of the candidates for a degree in this year, as the " ordo senioritatis " of the bachelors of arts for the year is omitted in the " See also:Grace Book." It is supposed that it was in 1665 that the method of fluxion first occurred to Newton's mind . There are several papers still existing in Newton's See also:handwriting bearing See also:dates 1665 and 1666 in which the method is described, in some of which dotted or dashed letters are used to represent fluxion,' and in some of which the method is explained without the use of dotted letters . Both in 1665 and in 1666 Trinity College was dismissed on account of the plague . On each occasion it was agreed, as appears by entries in the " Conclusion Book " of the college, bearing dates See also:August 7th, 1665, and June 22nd, 1666, and signed by the See also:master of the college, Dr See also:Pearson, that all See also:fellows and scholars who were dismissed on account of the pestilence be allowed one See also:month's See also:commons . Newton must have left college before August 1665, as his name does not appear in the See also:list of those who received extra commons on that occasion, and he tells us him-self in the See also:extract from his commonplace book already quoted that he was " forced from Cambridge by the plague " in the summer of that year .

He was elected a See also:

fellow of his college on the 1st of See also:October 1667 . There were nine vacancies, one of which was caused by the See also:death of See also:Abraham See also:Cowley in the previous summer, and the nine successful candidates were all of the same academical See also:standing . A few See also:weeks after his See also:election to a fellowship Newton went to Lincolnshire, and did not return to Cambridge till the February following, On the 16th of See also:March 1668 he took his degree of M.A . During the years 1666 to 1669 Newton's studies were of a very varied See also:kind . It is known that he purchased prisms and lenses on two or three several occasions, and also chemicals and a See also:furnace, apparently for chemical experiments;.; but he also employed part of his time on the theory of fluxions and other branches of pure mathematics . He wrote a See also:paper See also:Analysis per Equationes Numero Terminorum Infinitas, which, he put, See also:pro bably in June 1669, into the. hands of Isaac Barrow (them Lucasian See also:professor of mathematics), at the same time giving him permission to communicate the contents,to their See also:common friend John See also:Collins (1624-1683), a mathematician of no mean See also:order . Barrow did this on the 31st of July 1669, but kept the name of the author a See also:secret, and merely told Collins that he was a friend staying at Cambridge, who had a powerful See also:genius for such matters . In a subsequent See also:letter on the loth of August, Barrow expressed his See also:pleasure at See also:hearing the favourable opinion which Collins had formed of the paper, and added, " the name of the author is Newton, a fellow of our college, and a See also:young See also:man, who is only in his second year since he took the degree of master of arts, and who, with an unparalleled genius (eximio quo est acumine), has made very great progress in this See also:branch of mathematics." Shortly afterwards Barrow resigned his See also:chair, and was instrumental in securing Newton's election as his successor . Newton was elected Lucasian professor on the 29th of October 1669 . It was his See also:duty as professor to lecture at least once a See also:week in See also:term time on some portion of geometry, arithmetic, See also:astronomy, See also:geography, optics, See also:statics, or some other mathematical subject, and also for two See also:hours in the week to allow an See also:audience to any student who might come to consult with the professor on any difficulties he had met with . The subject which Newton See also:chose for his lectures was optics . The success which attended his researches in optics must have been great, although the results were known only through his own oral lectures, until he presented an account of them to the Royal Society in the See also:spring of 1672 .

On the 21st of December 1671 he was proposed as a See also:

candidate for See also:admission into the Royal Society by Dr See also:Seth See also:Ward, See also:bishop of See also:Salisbury, and on the 11th of January 1672 he was elected a fellow of the Society . At the See also:meeting at which Newton was elected a description of a reflecting See also:telescope which he had in-vented was read, and " it was ordered that a letter should be written by the secretary to Mr Newton to acquaint him of his election into the Society, and to thank him for the communication of his telescope, and to assure him that the Society would take care that all right should be done him with respect to this invention." In his reply to the secretary on the 18th of January 1672, Newton writes: " I See also:desire that in your next letter you would inform me for what time the society continue their weekly meetings; because, if they continue them for any time, I am purposing them to be considered of and examined an account of a philosophical See also:discovery, which induced me to the making of the said telescope, and which I doubt not but will prove much more grateful than the communication of that See also:instrument being in my See also:judgment the oddest if not the most considerable detection which hath hitherto been made into the operations of nature." The promise here made was fulfilled in a communication which Newton addressed to See also:Henry See also:Oldenburg, the secretary of the Royal Society, on the 6th of February 1672, and which was read before the society two days afterwards . The whole is printed in No . 8o of the Philosophical Transactions . After explaining his discovery of the See also:composition of white See also:light, he proceeds: " When I understood this, I left off my aforesaid See also:Glass works; for I saw, that the perfection of Telescopes was hitherto limited, not so much for want of glasses truly figured according to the prescriptions of Optick Authors (which all men have hitherto imagined), as because that Light itself is a Heterogeneous mixture of differently refrangible Rays . So that, were a glass so exactly figured as to collect any one sort of rays into one point, it could not collect those also into the same point, which having the same Incidence upon the same See also:Medium are See also:apt to suffer a different refraction . See also:Nay, I wondered, that seeing the difference of refrangibility was so great, as I found it, Telescopes should arrive to that perfection they are now at." He then points out why " the See also:object-glass of any Telescope cannot collect all the rays which come from one point of an object, so as to make them convene at its See also:focus in less See also:room than in a circular space, whose diameter is the Both part of the Diameter of its See also:Aperture: which is an irregularity some hundreds of times greater, than a circularly figured See also:Lens, of so small a See also:section as the Object-glasses of long Telescopes are, would cause by the unfitness of its figure, were Light See also:uniform." He adds: "This made me take reflections into See also:consideration, and finding them See also:regular, so that the See also:Angle of Reflection of all sorts of Rays was equal to their Angle of Incidence; I understood, that by their See also:mediation Optick See also:instruments might be brought to any degree of perfection imaginable, provided a Reflecting substance could be found, which would See also:polish as finely as Glass, and reflect as much light, as glass transmits, and the See also:art of communicating to it a Parabolick figure be also attained .. But these seemed very great difficulties, and I have almost thought them insuperable, when I further considered, that every irregularity in a reflecting superficies makes the rays stray 5 or 6 times more out of their due course, than the like irregularities in a refracting one; so that a much greater curiosity would be here requisite, than in figuring glasses for Refraction . " Amidst these thoughts I was forced from Cambridge by the Intervening Plague, and it was more than two years before I proceeded further . But then having thought on a See also:tender way of polishing, proper for metall, whereby, as I imagined, the figure also would be corrected to the last; I began to try, what might be effected in this kind, and by degrees so far perfected an Instrument (in the essential parts of it like that I sent to See also:London), by which I could discern Jupiters 4 Concomitants, and shewed them See also:divers times to two others of my acquaintance . I could also discern the Moon-like phase of See also:Venus, but not very distinctly, nor without some niceness in disposing the Instrument . " From that time I was interrupted till this last Autumn, when I made the other .

And as that was sensibly better than the first (especially for See also:

Day-See also:Objects), so I doubt not, but they will be still brought to a much greater perfection by their endeavours, who, as you inform me, are taking care about it at London." After a remark that microscopes seem as capable of improvement as telescopes, he adds: " I shall now proceed to acquaint you with another more notable difformity in its Rays, wherein the Origin of See also:Colour is unfolded: Concerning which I shall See also:lay down the See also:Doctrine first, and then, for its examination, give you an instance or two of the Experiments, as a specimen of the See also:rest . The Doctrine you will find comprehended and illustrated in the following propositions: " 1 . As the Rays of light differ in degrees of Refrangibility, so they also differ in their disposition to exhibit this or that particular colour . Colours are not Qualifications of Light, derived from Refractions, or Reflections of natural Bodies (as 'tis generally believed), but See also:original and connate properties, which in divers Rays are divers . Some Rays are disposed to exhibit a red colour and no other; some a yellow and no other, some a green and no other, and so of the rest . Nor are there only Rays proper and particular to the more eminent colours, but even to all their intermediate gradations . " 2 . To the same degree of Refrangibility ever belongs the same colour, and to the same colour ever belongs the same degree of Refrangibility . The least Refrangible Rays are all disposed to exhibit a Red colour, and contrarily those Rays, which are disposed to exhibit a Red colour, are all the least Refrangible: So the most refrangible Rays are all disposed to exhibit a deep See also:Violet Colour, and contrarily those which are apt to exhibit such a violet colour are all the most Refrangible . " And so to all the intermediate colours in a continued series belong intermediate degrees of refrangibility . And this See also:Analogy 'twixt colours, and refrangibility is very precise and strict; the Rays always either exactly agreeing in both, or proportionally disagreeing in both . " 3 .

The See also:

species of colour, and degree of Refrangibility proper to any particular sort of Rays, is not mutable by Refraction, nor by Reflection from natural bodies, nor by any other cause, that I could yet observe . When any one sort of Rave hath been well parted from those of other kinds, it hath afterwards obstinately retained its colour, notwithstanding my utmost endeavours to See also:change it . I have refracted it with Prismes, and reflected it with Bodies, which in Day-light were of other colours; I have intercepted it with the coloured film of See also:Air interceding two compressed plates of glass, transmitted it through coloured Mediums, and through Mediums irradiated with other sorts of Rays, and diversly terminated it; and yet could never produce any new colour out of it . It would by contracting or dilating become more brisk, or faint, and by the loss of many Rays, in some cases very obscure and dark; but I could never see it changed in specie . " Yet seeming transmutations of Colours may be made, where there is any mixture of divers sorts of Rays . For in such mixtures, the component colours appear not, but, by their 'mutual allaying each other constitute a midling colour." Further on, after some remarks on the subject of See also:compound colours, he says: " I might add more instances of this nature, but I shall conclude with this See also:general one, that the Colours of all natural Bodies have no other origin than this, that they are variously qualified to reflect one sort of light in greater plenty then another . And this I have experimented in a dark Room by See also:illuminating those bodies with uncompounded light of divers colours . For by that means any See also:body may be made to appear of any colour . They have there no appropriate colour, but ever appear of the colour of the light See also:cast upon them, but yet with this difference, that they are most brisk and vivid in the light of . their own day-light colour . Minium appeareth there of any colour indifferently, with which 'tis illustrated, but yet most luminous in red, and so Bise appeareth indifferently of any colour with which 'tis illustrated, but yet most luminous in blew . And therefore minium reflecteth Rays of any colour, but most copiously those indeed with red; and consequently when illustrated with day-light, that is with all sorts of Rays promiscuously blended, those qualified with red shall abound most in the reflected See also:binocular See also:vision . He also invented a reflecting See also:sextant for observing. the distance between the moon and the fixed stars,—the same in every essential as the instrument which is still in everyday use at See also:sea under the name of See also:Hadley's quadrant .

This discovery was communicated by him to See also:

Edmund See also:Halley in 1700, but was not published, or communicated to the Royal Society, till after Newton's death, when a description of it was found among his papers . In March 1673 Newton took a prominent part in a dispute in the university . The public oratorship See also:fell vacant, and a contest arose between the heads of the colleges and the members of the See also:senate as to the mode of electing to the See also:office . The heads claimed the right of nominating two persons, one of whom was to be elected by the senate . The senate insisted that the proper mode was by an open election . The See also:duke of See also:Buckingham, who was the See also:chancellor of the university, endeavoured to effect a See also:compromise which, he says, " I See also:hope may for the See also:present satisfy both sides . I propose that the heads may for this time nominate and the body comply, yet interposing (if they think See also:fit) a protestation concerning their plea that this election may not here-after pass for a decisive precedent in See also:prejudice of their claim," and, " whereas I understand that the whole university has chiefly consideration for Dr Henry Paman of St John's and Mr See also:Craven of Trinity College, I do recommend them both to be nominated." The heads, however, nominated Dr Paman and See also:Ralph Sanderson of St John's, and the next day one See also:hundred and twenty-one members of the senate recorded their votes for Craven and ninety-eight for Paman . On the See also:morning of the election a protest in which Newton's name appeared was read, and entered in the See also:Regent House . But the See also:vice-chancellor admitted Paman the same morning, and so ended the first contest of a non-scientific See also:character in which Newton took part . On the 8th of March 1673 Newton wrote to Oldenburg, the secretary of the Royal Society: " Sir, I desire that you will procure that I may be put out from being any longer Fellow of the Royal Societ : for though I See also:honour that body, yet since I see I shall neither profit them, nor (by See also:reason of this distance) can partake of the See also:advantage of their assemblies, I desire to withdraw." Oldenburg must have replied to this by an offer to apply to the Society to excuse Newton the weekly payments, as in a letter of Newton's to Oldenburg, dated the 23rd of June 1673, he says, " For your proffer about my quarterly payments, I thank you, but I would not have you trouble yourself to get them excused, if you have not done it already." Nothing further seems to have been done in the See also:matter until the 28th of January 1675, when Oldenburg informed " the Society that Mr Newton is now in such circumstances that he desires to be excused from the weekly payments." Upon this " it was agreed to by the See also:council that he be dispensed with, as several others are." On the 18th of February 1675 Newton was formally admitted into the Society . The most probable explanation of the cause why Newton wished to be excused from these payments is to be found in the fact that, as he was not in See also:holy orders, his fellowship at Trinity College would See also:lapse in the autumn of 1675 . It is true that the loss to his income which this would have caused was obviated by a patent from the crown in April 1675, allowing him as Lucasian professor to retain his fellowship without the See also:obligation of taking holy orders .

This must have relieved Newton's mind from a great See also:

deal of anxiety about pecuniary matters, as we find him in . See also:November 1676 subscribing £4o towards the See also:building of the new library of Trinity College . It is supposed that it was at Woolsthorpe in the summer of 1666 that Newton's thoughts were directed to the subject of gravity . See also:Voltaire is the authority for the well-known See also:anecdote about the See also:apple . He had his information from Newton's favourite niece Catharine See also:Barton, who married Conduitt, a fellow of the Royal Society, and one of Newton's intimate See also:friends . How much truth there is in what is a plausible and a favourite See also:story can never be known, but it is certain that tradition marked a See also:tree as that from which the apple fell, till 182o, when, owing to decay, the tree was cut down and its See also:wood carefully. preserved . light, and. by their prevalence cause it to appear of that colour . And for the same reason Bise, reflecting blew most copiously, shall appear blew by the excess of those Rays in its reflected Iight; and the like of other bodies . And that this is the intire and adequate cause of their colours, is See also:manifest, because they have no See also:power to change or alter the colours of any sort of Rays incident apart, but put on all colours indifferently, with which they are inlightened . Reviewing what I have written, I see the discourse it self will See also:lead to divers Experiments sufficient for its examination: And therefore I shall not trouble you further, than to describe one of those, which I have already insinuated . " In a darkened Room make a hole in the shut of a window whose diameter may conveniently be about a third part of an See also: