Sir Isaac Newton

Sir Isaac Newton, portrait gallery, 1833

Sir Isaac Newton
(25th December, 1642 – 20th March, 1727)
English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian

ISAAC NEWTON was born on Christmas-day, 1642 (0. S.), at Woolsthorpe, a hamlet in the parish of Colsterworth, in Lincolnshire. In that spot his family had possessed a small estate for more than a hundred years ; and his father died there a few months after his marriage to Harriet Ayscough, and before the birth of his son. The widow soon married again, and removed to North Witham, the rectory of her second husband, Mr. Smith, leaving her son, a weakly child who had not been expected to live through the earliest infancy, under the charge of her mother.

Early Life

Newton's education was commenced at the parish school, and at the age of twelve he was sent to Grantham for classical instruction. At first he was idle, but soon rose to the head of the school. The peculiar bent of his mind soon showed itself in his recreations. Ile was fond of drawing, and sometimes wrote verses ; but he chiefly amused himself with mechanical contrivances. Among these was a model of a wind-mill, turned either by the wind, or by a mouse enclosed in it, which he called the miller ; a mechanical carriage moved by the person who sat in it; and a water-clock, which was long used in the family of Mr. Clarke, an apothecary, with whom he boarded at Grantham.. This was not his only method of measuring time : the house at Woolsthorpe, whither he returned at the age of fifteen, still contains dials made by him during his residence there.

Death of father

Mr. Smith died in 1656, and his widow then returned to Woolsthorpe with her three children by her second marriage. She brought Newton himself also thither, in the hope that he might be useful in the management of the farm. This expectation was fortunately disappointed. When sent to Grantham on business, he used to leave its execution to the servant who accompanied him, and passed his time is reading, sometimes by the way-side, sometimes at the house of Mr. Clark. His mother no longer opposed the evident tendency of his disposition. He returned to school at Grantham, and was removed thence in his eighteenth year to Trinity College, Cambridge.

Trinity College

The 5th of June, 1660, was the day of his admission as a sizer into that distinguished society. He applied himself eagerly to the study of mathematics, and mastered its difficulties with an ease and rapidity
which he was afterwards inclined almost to regret, from an opinion that a closer attention to its elementary parts would have improved the elegance of his own methods of demonstration. In 1664 he became a scholar of his college, and in 1667 was elected to a fellowship, which he retained beyond the regular time of its expiration in 1675, by a special dispensation authorizing him to hold it without taking orders.
It is necessary to return to an earlier date, to trace the series of Newton's discoveries. This is not the occasion for a minute enumeration of them, or for any elaborate discussion of their value or explanation of their principles ; but their history and succession require some notice. The earliest appear to have related to pure mathematics. The study of Dr. Wallis's works led him to investigate certain properties of series, and this course of research soon conducted him to the celebrated Binomial Theorem. The exact date of his invention of the method of Fluxions is not known ; but it was anterior to 1666, when the breaking out of the plague obliged him for a time to quit Cambridge, and consequently when he was only about twenty-three years old.

Optical research

This change of residence interrupted his optical researches, in which he had already laid the foundation of his great discoveries. He had decomposed light into the coloured rays of which it is compounded,
and having thus ascertained the principal cause of the confusion of the images formed by refraction, he had turned his attention to the construction of telescopes which should act by reflection, and be free from this evil. He had not, however, overcome the practical difficulties of his undertaking, when his retreat from Cambridge for a time stopped this train of experiment and invention.


On quitting Cambridge Newton retired to Woolsthorpe, where his mind was principally employed upon the system of the world. The theory of Copernicus and the discoveries of Galileo and Kepler had at
length furnished the materials from which the true system was to be deduced. It was indeed all involved in Kepler's celebrated laws.

The equable description of areas proved the existence of a central force ; the elliptical form of the planetary orbits, and the relation between their magnitude and the time occupied in describing them, ascertained the law of its variation. But no one had arisen to demonstrate these necessary consequences, or even to conjecture the universal principle from which they were derived. The existence of a central force had been surmised, and the law of its action guessed at; but no proof had been given of either, and little attention had been awakened by the conjecture.

The apple falls

Newton's discovery appears to have been quite independent of any speculations of his predecessors. The circumstance attending it are well known : the very spot in which it first dawned upon him is ascertained. He was sitting in the garden at Woolsthorpe, when the fall of an apple called his attention to the force which caused its descent, to the probable limits of its action and law of its operation. Its power was not sensibly diminished at any distance at which experiments had been made : might it not then extend to the moon and guide that luminary in her orbit ? It was certain that her motion was regulated in the same manner as that of the planets round the sun : if, therefore, the law of the sun's action could be ascertained, that by which the earth acted would also be found by analogy. Newton, therefore, proceeded to ascertain by calculation from the known elements of the planetary orbits, the law of the sun's action.

The great experiment remained : the trial whether the moon's motions showed the force acting upon her to correspond with the theoretical amount of terrestrial gravity at her distance. The result was disappointment. The trial was to be made by ascertaining the exact space by which the earth's action turned the moon aside from her course in a given time. This depended on her actual distance from the earth, which was only known by comparison with the earth's diameter. The received estimate of that quantity was very erroneous ; it proceeded on the supposition that a degree of latitude was only sixty English miles, nearly a seventh part less than its actual length. The calculation of the moon's distance and of the space described by her, gave results involved in the same proportion of error ; and thus the space actually described appeared to be a seventh part less than that which corresponded to the theory. It was not Newton's habit to force the results of experiments into conformity with hypothesis. He could not, indeed, abandon his leading idea, which rested, in the case of the planetary motions, on something very nearly amounting to demonstration. But it seemed that some modification was required before it could be applied to the moon's motion, and no satisfactory solution of the difficulty occurred. The scheme therefore was incomplete, and, in conformity with his constant habit of producing nothing till it was fully matured, Newton kept it undivulged for many years.

Reflecting telescopes

On his return to Cambridge Newton again applied himself to the construction of reflecting telescopes, and succeeded in effecting it in 1668. In the following year Dr. Barrow resigned in his favour the Lucasian professorship of mathematics, which Newton continued to hold till the year 1703, when Whiston, who had been his deputy from 1699, succeeded him in the chair. On January 11, 1672, Newton was elected a Fellow of the Royal Society. He was then be known by the invention of the reflecting telescope ; but immediately on his election he communicated to the Society the particulars of his theory of light, on which he had already delivered three courses of lectures at Cambridge, and they were shortly afterwards published in the Philosophical Transactions.

It is impossible here to state the various phenomena of light and colours which were- first detected and explained by Newton. They entirely changed the science of optics, and every advance which has since been made in it has only added to the importance and confirmed the value of his observations. The success of the new theory was complete. Newton, however, was much vexed and harassed by the discussions which it occasioned. The annoyance which he thus experienced made him even think of abandoning the pursuit of science, and although it failed to withdraw him from the studies to which he was devoted, it confirmed him in 'his unwillingness to publish their results.

The next few years of Newton's life were not marked by any remarkable events. They were passed almost entirely at Cambridge, in the prosecution of the researches in which he was engaged. The most important incident was the communication to Oldenburgh, and, through him, to Leibnitz, that he possessed a method of determining maxima and minima, of drawing tangents, and performing other difficult mathematical operations. This was the method of fluxions, but he did not announce its name or its processes. Leibnitz, in return, explained to him the principles and processes of the Differential Calculus. This correspondence took place in the years 1676 and 1677: but the method of fluxions had been communicated to Barrow and Collins as early as 1669, in a tract, first printed in 1711, under the title 'Analysis per equationes numero terminorum infinitas.' Newton had indeed intended to publish his discovery as an introduction to an edition of Kinckhuysen's Algebra, which he undertook to prepare in 1672 ; but the fear of controversy prevented him, and the method of fluxions was not publicly announced till the appearance of the Principia in 1687. The edition of Kinckhuysen's treatise did not appear; but the same year, 1672, was marked by Newton's editing the Geography of Varenius.

Theory of gravitation

In 1679 Newton's attention was again called to the theory of gravitation, and by a fuller investigation of the conditions of elliptical motion, he was confirmed in the opinion that the phenomena of the planets were referable to an attractive force in the sun, of which the intensity varied in the inverse proportion of the square of the distance. The difficulty about the amount of the moon's motion remained, but it was shortly to be removed. In 1679 Picard effected a new measurement of a degree of the earth's surface, and Newton heard of the result at a meeting of the Royal Society in June, 1682. He immediately returned home to repeat his former calculation with these new data. Every step of the process made it more probable that the discrepance which had so long perplexed him would wholly disappear and so great was his excitement at the prospect of entire success that he was unable to proceed with the calculation, and intrusted its completion to a friend. The triumph was perfect, and he found the theory of his youth sufficient to explain all the great phenomena of nature.

From this time Newton devoted unremitting attention to the development of his system, and a period of nearly two years was entirely absorbed by it. In 1684 the outline of the mighty work was finished; yet it is likely that it would still have remained unknown, had not Halley, who was himself on the track of some part of the discovery, gone to Cambridge in August of that year to consult Newton about some difficulties he had met with. Newton communicated to him a treatise De Motu Corporum, which afterwards, with some additions, formed the first two books of the Principia. Even then Halley found it difficult to persuade him to communicate the treatise to the Royal Society, but he finally did so in April, 1686, with a desire that it
should not immediately be published, as there were yet many things to complete. 'Hooke, whose unwearied ingenuity had guessed at the true law of gravity, immediately claimed to himself the honour of the
discovery ; how unjustly it is needless to say, for the merit consisted not in the conjecture but the demonstration. Newton was inclined in consequence to prevent the publication of the work, or at least of
the third part, be Mundi Systemate, in which the mathematical conclusions of the former books were applied to the system of the universe. Happily his reluctance was overcome, and the whole work was published in May, 1687. Its doctrines were too novel and surprising to meet with immediate assent; but the illustrious author at once received the tribute of admiration for the boldness which had formed, and the skill which had developed his theory, and he lived to see it become the common philosophical creed of all nations.

University of Cambridge and the Benedictine monk

We next find Newton acting in a very different character. James II. had insulted the University of Cambridge by a requisition to admit a Benedictine monk to the degree of Master of Arts without taking the oaths enjoined by the constitution of the University. The mandate was disobeyed ; and the Vice-Chancellor was summoned before the Ecclesiastical Commission to answer for the contempt. Nine delegates, of whom Newton was one, were appointed by the University to defend their proceedings ; and their exertions were successful. He was soon after elected to the Convention Parliament as  member for the University of Cambridge. That parliament was dissolved in February, 169Q, and Newton, who was not a candidate for a seat in the one which succeeded it, returned to Cambridge, where he continued to reside for some years, notwithstanding the efforts of Locke, and some other distinguished persons with whom he had become acquainted in London, to fix him permanently in the metropolis.

During this time he continued to be occupied with philosophical research, and with scientific and literary correspondence. Chemical investigations appear to have engaged much of his time ; but the principal results of his studies were lost to the world by a fire in his chambers about the year 1692. The consequences of this accident have been very differently related. According to one version, a favourite dog, called Diamond, caused the mischief, and the story has been often told, that Newton was only provoked, by the loss of the labour of years, to the exclamation, " Oh, Diamond ! Diamond ! thou little knowest the mischief thou hast done." Another, and probably a better authenticated account, represents the disappointment as preying deeply on his spirits for at least a month from the occurrence.
We have more means of tracing Newton's other pursuits about this time. History, chronology, and divinity were his favourite relaxations from science, and his reputation stood high as a proficient in these studies. In 1690 he communicated to Locke his Historical account of two notable corruptions of the Scriptures,' which was first published long after his death. About the same time he was engaged in those researches which were afterwards embodied in his Observations on the Prophecies : and in December, 1692, he was in correspondence with Bentley on the application of his own system to the support of natural theology.

Ill Health

During the latter part of 1692 and the beginning of 1693 Newton's health was considerably impaired, and he laboured in the summer under some epidemic disorder. It is not likely that the precise character or amount of his indisposition will ever be discovered ; but it seems, though the opinion has been much controverted, that for a short time it affected his understanding, and that in September, 1693, he was not in the full possession of his mental faculties. The disease was soon removed, and there is no reason to suppose that it ever recurred. But the course of his life was changed ; and from this time forward he devoted himself chiefly to the completion of his former works, and abstained from any new career of continued research.
His time indeed was less at his own disposal than it had been.

Wardenship of the Mint

In 1696, Mr. Montague, the Chancellor of the Exchequer, an early friend of Newton, appointed him to the Wardenship of the Mint, and in 1699 he was raised to the office of Master. He removed to London, and was much occupied, especially during the new coinage in 1696 and 1697, with the duties of his office. Still he found time to superintend the editions of his earlier works, which successively appeared with very material additions and improvements. The great work on Optics appeared for the first time in a complete form in 1704, after the death of Hooke had freed Newton from the fear of new controversies. It was accompanied by some of his earlier mathematical treatises ; and contained also, in addition to the principal subject of the work,suggestions on a variety of subjects of the highest philosophical interest, embodied in the shape of queries. Among these is to, be found the first suggestion of the polarity of light ; and we may mention at the same time, although they occur in a different part of the work, the remarkable conjectures, since verified, of the combustible nature of the diamond, and the existence of an inflammable principle in water.
The second edition of the Principia appeared under the care of Cotes in 1713, after having been the subject of correspondence between Newton and his editor for nearly four years. Dr. Pemberton published a third edition in 1725, and he frequently communicated about the work with Newton who was then eighty-two years old.

Latter life

These were the chief scientific employments of Newton's latter life: and it is not necessary to particularize all its minor, details. In 1712 he made some improvements in his Arithmetica Universalis, a work containing his algebraical discoveries, of which Whiston had surreptitiously published an edition in 1707. It is also worthy of remark that at the beginning of the year 1697, John Bernouilli addressed two problems as a challenge to the mathematicians of Europe, and that Leibnitz in 1716 made a similar appeal to the English analysts; and that Newton in each case undertook and succeeded in the investigation.

This enumeration of Newton's philosophical employments has far outrun the order of time. After his return to London, compliments and honours flowed in rapidly upon him. In 1699 he was elected one of the first foreign associates of the Academie des Sciences at Paris; and in 1701 he was a second time returned to Parliament by the 'University of Cambridge. He did not, however, long retain his seat. At the election in 1705 he was at the bottom of the poll, and he does not appear again to have been a candidate. In 1703 he was chosen President of the Royal Society, and held that office till his death. In 1705 he was knighted by Queen Anne upon her visit to Cambridge.

Newton's life in London was one of much dignity and comfort. He was courted by the distinguished of all ranks, and particularly by the Princess of Wales, who derived much pleasure from her intercourse both with him and Leibnitz. His domestic establishment was liberal, and was superintended during great part of his time by his niece, Mrs. Barton, a woman of much beauty and talent, who married Mr. Conduitt, his assistant and successor at the Mint. Newton's liberality was almost boundless, yet he died rich.

The only material drawback to Newton's enjoyment during this portion of his life, seems to have arisen from controversies as to the history and originality of his discoveries ; a molestation to which his slowness to publish them very naturally exposed him. There was a long and angry dispute with Leibnitz about the priority of fluxions or the differential calculus ; and, after the fashion of most disputes, it diverged widely from the original ground, and it became necessary for Newton to vindicate the religious and metaphysical tendencies of his greatest works. His success was complete on all points. Leibnitz does not appear to have been acquainted with the method of fluxions at the time of his own discovery, but there is now no doubt of Newton's having preceded him by some years ; and the attacks made on the tendency of Newton's discoveries have long been remembered only as disgracing their author. But such discussions had always been distasteful to Newton, and this controversy, which was conducted with great rancour by his opponents and some of his supporters, embittered his later years.

The same fate awaited him in another instance. His system of Chronology had been long conceived, but he had not communicated it to any one until he explained it to the Princess of Wales. At her desire, he afterwards, in 1718, drew up a short abstract of it for her use, and sent it to her on condition that no one else should see it. She afterwards requested that the Abbe Conti might have a copy of it, and Newton complied, but still on the terms that it should not be farther divulged. Conti, however, showed the manuscript at Paris to Freret, who, without the author's permission, translated and published it with observations in opposition to its doctrines. Newton drew up a reply which was printed in the Philosophical Transactions for 1725, and this was the signal for a new attack by Souciet. Newton was then roused to his last great exertion, that of fully digesting his system ; which as yet existed only in confused papers, and preparing it for the press. He did not live to complete his task, but the work was left in a state of great forwardness, and was published in 1728 by Mr. Conduitt. Its value is well known. As a refutation of the systems of chronology then received, it is almost demonstrative ; and the affirmative conclusions, if not always minutely correct, or even generally satisfactory, are yet among the most valuable contributions which science has made to history.

With the exception of the attack of 1693, Newton's health had usually been very good. But he suffered much from stone during the last few years of his life. His mental faculties remained in general unaffected, but his memory was much impaired. From the year 1725 he lived at Kensington, but was still fond of going occasionally to London, and visited it on February 28th, 1727, to preside at a meeting of the Royal Society. The fatigue appears to have been too great : for the disease attacked him violently on the 4th of March, and he lingered till the 20th, when he died. His sufferings were severe, but his temper was never soured, nor the benevolence of his nature obscured. Indeed his moral was not less admirable than his intellectual character, and it was guided and supported by that religion, which he had studied not from speculative curiosity, but with the serious application of a mind habitually occupied with its duties, and earnestly desirous of its advancement.


Newton died without a will, and his property descended to Mrs. Conduitt and his other relations in the same degree. He was buried with great pomp in Westminster Abbey, where there is a monument to his memory, erected by his relations. His Chronology appeared, as has been already mentioned, almost immediately after his death ; and the Lectiones Opticae, the substance of his lectures at Cambridge in the years 1669, 1670, and 1671, were published from his manuscripts in 1729. In 1733, Mr. Benjamin Smith, one of the descendants of his mother's second marriage, published the Observations on the Prophecies. These, in addition to the works already mentioned, are Newton's principal writings ; there are, however, several small-- tracts, some of which appeared during his lifetime, and some after death, which it is not necessary here to specify. They would have conferred much honour on most philosophers ;—they are hardly remembered- bered in reckoning up Newton's titles to fame.

Many portraits of Newton are in existence. The Royal Society-possesses two ; and Lord Egremont is the owner of one, which engraved as the frontispiece to Dr. Brewster's Life of Newton.. Trinity College, Cambridge, abounds in memorials of its greatest ornament. Almost every room dedicated to public purposes possesses a picture of him, and the chapel is adorned by Roubiliac's noble statue The library also has a bust by the same artist, of perhaps even superior excellence. As works of art these are far superior to any of the paintings extant : but they have not the claim to authenticity possessed by the contemporary portraits. It is remarkable, that until the recent publication of Dr. Brewster's life, no one had thought it worth while to devote an entire work to the history of so remarkable a man as Newton. There is, however, an elaborate memoir of him, written by M. Biot, in the Biographic Universelle, which has been republished in the Library of Useful Knowledge.