We are this evening assembled to receive at the hands of the noble Patron of this Institution, the bust of our illustrious countryman, Sir Isaac Newton.1 On such an occasion it seems not inappropriate to devote a short time to the contemplation of the mind and character of that gifted individual. Through the partiality of friends, I have been requested to prepare an address on the genius and discoveries of Newton. In meeting this wish, I cannot but feel conscious of my own incompetency to do justice to so great a theme. It would not be difficult, indeed, to collect such materials as might afford a connected view of his life; or, if from popular anecdotes it were required to form an estimate of his character, the task would be easy, for with such the world has been abundantly supplied. Our present business is rather with the mind of Newton; and if, as the humblest of his disciples, I shall be thought to have succeeded in showing what were indeed the characteristics of that powerful mind, my end will be answered; or, failing in the attempt, I may hope for some measure of indulgence, when it is considered how vast a subject I have undertaken.
Sir Isaac Newton was born in the Manor House at Woolsthorpe, near Grantham, in the county of Lincoln, on Christmas Day, in the year 1642. The house in which this event took place is, I believe, now standing, and in the possession of the Turner family. In this habitation Newton continued until his 12th year, when he was sent to the free-school at Grantham. It was during his residence there, that the earliest recorded indications of talent were given.2 His mind appears at that time to have been much occupied with mechanical contrivances, yet not so deeply as to exclude the lighter amusements of drawing, and even poetry. The scientific adjustment of the paper-kite and its appendages, and the construction of sun-dials, water-clocks, and mill-work, afforded him a philosophical past-time, which could not fail to invigorate his natural powers of invention. Even his sleeping apartment is said to have been garnished round with the untutored productions of his knife and pencil.3
These circumstances have been considered as indicative of his future greatness, and we might give credence to the omen, were it not that the promise of early genius has been rarely answered. In the intellectual, as in the physical constitution, a too early development is often followed by a feeble and transient maturity. The youthful occupations of Newton rather manifest the workings of an ardent and inquiring spirit, than of a mind already invested with the features of genius: above all, they exhibit a character of resolution and untiring diligence, which is in every pursuit the surest and safest road to excellence.
At the age of eighteen, Newton was sent to Cambridge, and entered as a scholar of Trinity College. Previous to this period he does not appear to have made much progress in his studies; but his mental powers now attaining, after a long repose, their natural and healthy development, soon made up for the deficiency. Without preparatory reading, he made himself master of Des Cartes’ Geometry, of Wallis’ Arithmetic of Infinites, and of Kepler’s Optics. It has been said that on these subjects he became, while yet a student, more deeply learned than his tutors: but on what authority the assertion is made, I know not. On the resignation of Dr. Barrow, he was appointed his successor in the Lucasian chair of Mathematics, having previously obtained a Fellowship.
From this period we may date the commencement of his brilliant public career. The first subject of importance that engaged his attention was the phenomena of prismatic colours, observed a short time before by Grimaldi.4 The results of Newton’s inquiries were communicated to the Royal Society in the year 1675, and afterwards published with most important additions in 1704. The production was entitled “Optics; or, a Treatise on the Reflections, Refractions, Inflections, and Colours of Light.”5 It is certainly one of the most elaborate and original of his works, and carries on every page the traces of a powerful and comprehensive mind.
The doctrine of refraction had for some time engaged the attention of the learned, and considerable advances had been made; but it was Newton’s destiny to explore a new and untrodden path, invested with a far higher interest: the Philosophy of Colours. The opinions which prevailed before on this subject were purely hypothetical, yet wanting that which is most essential to an hypothesis: the merit of plausibility. At the very outset of his experiments, he deduced that fundamental truth, that white light is not homogeneous, but produced by a mixture of other colours. As he proceeded in his researches, a series of new and more intricate truths unfolded themselves till at length his labours were crowned by the completion of that magnificent theory, which is contained in the first book of his Optics.
From the analysis of solar light, Newton proceeded to speculations of a yet higher order. The colours of natural bodies had been hitherto totally inexplicable: I do not know that a rational solution of that difficult question had ever been attempted. If attempted, it must have been abandoned in despair. A field of rich discovery was waving its untried harvest before him, and waiting for that powerful hand which should have strength to wield the sickle.
Newton began his researches by observations on the phenomena of coloured rings. These he accounted for by the theory of “Fits of Easy Reflection and Transmission”; a theory which, though it only rests on hypothesis, serves sufficiently well to explain the appearances.6 The results of this investigation he applied by a most beautiful analogy to explain the colours of thin plates, and to determine the relation between the thickness of the plate and the colour produced. I may refer for a familiar illustration to the splendid colouring of soap bubbles: in this instance the colour is not owing to the material of which the bubble is formed, but depends on the thickness of its sides. The colour indeed is not presented until the sides have assumed a certain degree of attenuation.
On these grounds, Newton’s theory of the colours of natural bodies is founded. His argument is as follows: First, The colour of a thin plate depends upon its relative degree of attenuation. Second, If a thin plate be divided into shreds and fragments, a mass of such fragments will preserve the original colour of the plate. Lastly, The parts of all natural bodies, being like so many fragments of a plate, must, on the same grounds, preserve the same colour.
The above theory is sufficient to account for some of the more vivid and beautiful of Nature’s hues. The colours of feathers, insects’ wings, gossamer, etc., are doubtless owing to this cause; but as a general theory of colour it is manifestly inadequate. Philosophers have been at some pains to point out its defects, though unfortunately they have been unable to find another half as general to supply its place.
Notwithstanding all the objections which may be urged, it still remains a gigantic memorial of the vastness of that mind in which it was conceived. One characteristic of Newton’s mind it strongly exemplifies: the faculty of generalizing; and this, if I mistake not, was one of his chief points. In the instance before us, he commences his research by experimenting on thin plates of air: from this he deduces the germ of his theory, and to its laws he subjects, in the course of his inquiry, the whole superstructure of material things. It is true that his theory has been left imperfect; admit that in some of the applications it has failed. But at the same time we must acknowledge that in what he failed he did not fail as a common mortal, and that the marshalled intellect of Europe has vainly endeavoured to fill up the chasm!
There is in the very idea of light something so vague and intangible, that our imagination can with difficulty attribute to it an independent and material existence. Yet granting this, and assuming as our data, that under certain known circumstances, known impressions are received which we designate colour, the analysis of its primitive elements, and of the laws and effects of their combinations, would still remain a mighty problem. It is singular, that of all the subtle and mysterious agencies, light, heat, electricity, attraction, connected by one general link, and commissioned by their Author to confer upon dead matter the life and beauty of the universe, light is the only one that has yet thoroughly unfolded the harmony of its laws and submitted itself to human scrutiny. That genius which stands foremost in the triumph was the calm, patient, all-surmounting genius of Newton.
Newton’s earlier optical labours were interrupted by the breaking out of the plague in Cambridge. He then retired to Woolsthorpe, and there continued two years. During that period he conceived the idea that the moon’s motion might be regulated by the attraction of the earth. It is generally supposed that his attention was directed to this subject by observing the falling of an apple. If this tradition be correct, it strongly teaches us what vast effects may arise from trivial or common occurrences, when the latent energies of nature or of mind are thereby roused into action. The falling of an apple was an every-day occurrence, yet its moral consequences have been, to all human appearance, greater than the downfall of an empire. It had touched upon some hidden spring—some sleeping and folded energy: a train of thought was excited, which, though interrupted, was never abandoned, until the foundation was laid of the great science of Physical Astronomy, that science which, in its subsequent developments, has, above all others, demonstrated the economy of the universe, the capabilities of our own immortal nature, and the majesty of the Being who created them.
I have said that Newton’s inquiries on gravitation met with an interruption: that interruption was occasioned by an error in his data. In his calculations he had made use of the common but erroneous admeasurement of 60 miles to a degree of the terrestrial meridian, instead of the more accurate approximations which have been since obtained.7 The primary object of his inquiries was to compare the force of gravity in the lunar orbit with that obtaining on the earth’s surface. The results at which he arrived did not, as might be expected, answer his ideas. The subject was laid aside until more accurate data enabled him to verify his hypothesis.
It is a very prevalent, but mistaken opinion, that the doctrine of universal gravitation originated exclusively with Newton. The existence of such an influence is strongly advocated by Plutarch; it is indistinctly intimated in the mystic writings of Plato. It is certain, too, that about the time of Newton’s investigations, an opinion was spreading among the more profound thinkers of the age, that the celestial motions were in some measure influenced by the action of such a principle; but the prevalent and orthodox opinion was, that the planets were carried round the sun by the revolutions of an everlasting whirlpool, like straws on an eddy of water. This system was invented by Des Cartes [René Descartes], and is for that reason generally called the Cartesian Philosophy, or the System of Vortices.
In the awarding of scientific honours, it is admitted that the discovery of a new principle is due to him who first proves its existence. On this ground Newton’s claim to the discovery of universal gravitation must rest. He found it an unsupported hypothesis—he left it an established truth. The discovery of this principle, with its most important applications, was announced to the world in the year 1687, by the publication of the “Principia, or Mathematical Principles of Natural Philosophy.”8 The title of the Work is such as to render it a forbidden book to the generality of readers; but since the subjects of which it treats are among the most interesting as well as the sublimest of human studies, it may not be amiss briefly to advert to its contents.
The object of the “Principia” is twofold: to demonstrate the law of planetary influence, and to apply that law to the purposes of calculation. It is true, that in certain portions of the work, investigations of a different nature are introduced, but it is possible to trace throughout them all a greater or lesser degree of connection with the main topic.
Three properties of the celestial motions had been discovered by Kepler, the astronomer, from whom they borrowed their name. By these properties the truth of a new theory was to be tested. The first of Kepler’s laws (for thus they are designated), defined the orbit or path of a planet to be an ellipse; the second law determined the velocity of the body in any portion of that orbit; and the third expressed the whole time of a revolution in an orbit of known dimensions. Newton showed that these laws were the necessary results of a gravitating force according to the assumed law of its variation, and thus placed the existence of that principle beyond all legitimate doubt. The first object of the “Principia” was now attained. He had fully shown the principal motions of the planets to be such as would obtain in a system of bodies revolving by a mutual attraction varying in intensity as the inverse square of the distance. But there yet remained many important phenomena to be accounted for: the tides of the ocean, the spheroidal figure of the earth and planets, and the irregularities of the lunar orbit. All these requiring the application of his new principle, may be considered as the second object of the “Principia.” To accomplish the explanation of these, some more powerful analysis than had hitherto been employed was necessary. For this purpose he unfolded the principles of the celebrated doctrine of fluxions or limits, and applied them with consummate skill in his subsequent researches. But from the imperfect form in which his new calculus then existed, the objects of its application were but partially attained. Yet his attempts, though not always, from the reason I have stated, completely successful, are never unworthy of their author. It was the struggle of a great mind with limited means, always exhibiting a mastery over them, and often rising far above them. There are instances in which he seems to have abandoned the ordinary mode of inquiry as insufficient or inelegant, and to have relied on the sole force of his genius in detecting and employing those hidden analogies which could alone surmount the difficulty.
The peculiar disadvantages under which Newton laboured will be better understood when a few remarks have been made on the nature of his proposed investigations, and the means which he possessed of pursuing them. And, perhaps, the simplest case for illustration will be found in the inequalities of the moon’s motions. It is, moreover, the foundation upon which his ulterior researches on the subjects we are considering, mainly depend.
To determine with accuracy the position of the moon at any given period, had long been a desideratum in practical science. Until this object should be attained, all substantial improvements in the art of navigation, and in the accuracy of sea charts, were hopeless. Now it had been shown in the earlier portion of the “Principia,” that the motions of a planetary body, when influenced by the sole attraction of another, were accurately elliptical. Such relations of velocity and time had also been assigned, as rendered its position determinable to any required exactness. Had the moon, therefore, been solely under terrestrial influence, no further search would have been necessary, and the most important branch of physical astronomy would have begun and ended with Newton. But in the actual operations of nature, such a case is far from obtaining. The moon is not only swayed by the attraction of the earth, but in some measure influenced by that of the sun. The action of the latter body has been technically called disturbance, because its effects are to disturb, or in some measure, derange the motions of the attracted body. To account for the extent and variations of every observed derangement by the theory of gravity, was Newton’s first aim; to calculate the amount of the principal derangement, his second. In both attempts the profound skill of the workman and the imperfection of his means, are powerfully shown. The instrument of his research was, as I have stated, the method of limits, and the fluxionary calculus; the latter existing, as I have likewise observed, in a rude form, but susceptible of indefinite improvement. But when the same instrument was applied to the same end by his disciples in France, it had become doubly commodious and powerful, from the aggregate improvements of a century.
There was yet another disadvantage attaching to the whole of Newton’s physical inquiries, which, though it gave rise to the most sublime applications of geometry, must yet be considered as having presented an insurmountable barrier to his progress, the want of an appropriate notation for expressing the conditions of a dynamical problem, and the general principles by which its solution must be obtained. By the labours of La Grange, the motions of a disturbed planet are reduced with all their complication and variety to a purely mathematical question. It then ceases to be a physical problem; the disturbed and disturbing planet are alike vanished; the ideas of time and force are at an end; the very elements of the orbit have disappeared, or only exist as arbitrary characters in a mathematical formula.
In Newton’s investigations this felicitous transformation could not take place. Nature must be combated on her own grounds: the disturbing force is analyzed: its effect must be considered in every variety of position—above, below, and in coincidence with the ecliptic plane: from syzigy to quadrature, and thence again to syzigy, the same influence is to be followed, and its resulting effects determined. The everlasting wheels of the universe are before us, and their revolutions are to be traced through all the changing varieties of cause, circumstance, and effect. It is not to be denied, that this mode of investigation is attended with such complication as to render it decidedly inferior, both in power and facility, to the methods now pursued. Yet there is one respect which it possesses an advantage. Following step by step the process of Newton’s demonstrations, we become more familiar with the machinery which they are intended to unravel, than if our results were immediately obtained by the discussion of an analytical formula. This consideration is, I am persuaded, of some importance to the young astronomer.
In speaking of Newton’s optical discoveries, I have remarked on the power of generalizing as a prominent feature of his mind: a portion of the “Principia,” on which I have now been commenting, abounds with instances of this faculty. Perhaps its most remarkable exercise may be the observed problem of equinoctial precession. In this particular case he passes from the consideration of solar influence on a revolving satellite, a point already determined, to the influence of the same power on an ellipsoidal shell encompassing a revolving planet. Of such investigations, however, sufficient has already been said.
But it was not in the power of generalizing alone that Newton differed from all other men. In this one respect, indeed, he resembles the lawgiver of an old philosophy, Aristotle. But there is this material difference, that in the latter it was the main and distinguishing feature; in Newton, it was subservient to, and perhaps resulted from, qualities of a much loftier order: vastness of comprehension, a deep and far-seeing penetration, and last and chief (the attribute of character rather than of mind), unwearied and unconquerable resolution. These were the elements of his intellectual greatness. They have stamped with immortality every page of the “Principia.”
It has often been observed, that the biography of eminent literary men presents but few objects of general interest. The progress of their lives seems only measured by the order of their attainments and productions. From these we estimate the gradual rise and advance of mind and character, through every successive change, from the nursery to the grave. But in Newton’s history there was one circumstance of a different order, which, from the remarkable effect it produced, cannot be passed over in silence. I allude to the well-known circumstance of the burning of his papers by the throwing down of a lighted candle. The accident was occasioned by a little dog, and called forth that remarkable expression of patience, “Oh Diamond, Diamond, thou little knowest the mischief thou hast done.”9
The sudden loss of the labours of many years, acting on a frame already morbid with the irritation of an epidemic disorder, is believed for some time to have affected his understanding. But whatever may have been the nature of the affection, one thing is certain, the course of his life was altered. From this period he entered upon no extended field of scientific inquiry. The volume of nature was, in a great measure, relinquished, and that of revelation henceforth occupied its place. A change so important as the one alluded to, has by some been imagined to proceed from the temporary aberration which he is supposed to have experienced. Such a conclusion appears to me at best to be far-fetched. It is not difficult to conceive that illness may have deepened the tone of a naturally solemn and devotional mind. Perhaps, too, that universal satiety which mingles even with the cup of knowledge may in some measure have fallen upon him, who of any men had drank most deeply; or the advance of years, and the impossibility of restoring his lost papers, may have been of themselves sufficient to effect the change. I do not say that to any of these circumstances his theological writings are due, because all our suppositions are only founded on probability; but I would intimate that it is unphilosophical to attribute to a temporary insanity, those religious impressions which so many other causes may have tended to develop.
From the period of this critical illness until that which terminated in death, the current of his days glided calmly and evenly along. All disputes on the merit and originality of his discoveries were now at an end, and he was daily receiving those tributes of honour and affection which had long been acknowledged his due. In the year 1699 he was appointed Master of the Mint; subsequently the honour of knighthood and the Presidency of the Royal Society were conferred upon him. The intervals of his public duties were chiefly employed in theological enquiries, yet so as not to neglect the subsidiary studies of chronology and history. All these sciences he has enriched. His chronology, and the occasional speculations in mathematics which he has left us, are sufficient to show that the vigour of his early years had not departed. His observations on the book of Daniel and the Revelation of St. John will remain as monuments of his vast learning and deep sagacity so long as the pages of the prophet and the evangelist shall continue to retain their claim on the interest and veneration of mankind.
We cannot but consider this later portion of Newton’s life as highly and singularly happy: all that can make old age honourable he possessed, with scarce a shadow of its dotage and infirmities. He was not a father, but the natural affections were in him expanded into the broad principle of universal philanthropy. Subdued passions, moderate wealth, and the much-loved blessing of peace, all tended to smooth and to illumine the rugged path of declining life. If desire of fame had been the meteor of his youth, it could not now disturb his repose, for he had long been at the summit of all earthly ambition. If the recollection of the “single talent well employed” be attended with a pleasure, surely that pleasure must have been felt in its keenest relish by him, who had received from his Maker ten golden talents, and well employed them all. These are the materials of happiness, and all these were possessed by Newton. But more than these, the support and solace of his faith, the prospect of future happiness which grows brighter as all other prospects decay, these were unalienably his. And though genius has too often been a wandering star, the minister of licentiousness, or the associate of scepticism, in his life we have ample testimony that such is not a natural or a necessary alliance. Nor perhaps is there less to admire in the high excellence and unblemished purity of his moral character, than in that halo of philosophical glory which has gathered around his name.
In the year 1722 Newton felt the first inroads of that fatal malady, which at length terminated in death. By rigid economy of diet he was enabled to ward off for some years the final catastrophe, and to enjoy long intervals of health. His disease was of a trying and painful nature, and encouraged no hopes of an ultimate recovery. In the February of 1727 it assumed a more virulent form, and indicated, with no dubious symptoms, the rapid approach of death. The paroxysms of the disorder were now frequent and violent, and during their continuance the sweat of agony often started upon his brow. He did not complain. Newton never murmured at the severity and length of his affliction. His intellect continued bright and settled until within a short period of his dissolution. On the evening of Saturday the 18th of the following March, he fell into a state of insensibility; on Monday the 20th, Sir Isaac Newton was no more.
He lies buried in Westminster Abbey: a monument is there erected to his memory, bearing a Latin inscription, of which the following is a translation, as literal as the transfer of idiom will allow.
Here lies SIR ISAAC NEWTON, KNIGHT,
Who, with a vigour of mind almost superhuman,
Guided by the light of his own Mathesis,
First demonstrated the motions and figures of the planets,
The paths of the comets, and the tides of the ocean.
He thoroughly investigated
What none before had even suspected,
The different varieties of the rays of light,
And the properties of the colours thence proceeding:
A diligent, sagacious, and faithful interpreter
Of Nature, of Antiquity and of the Holy Scriptures,
He asserted in his Philosophy the Majesty of God,
And exhibited in his conduct the simplicity of the Gospel.
Let mortals rejoice
That there has existed such and so great an ornament of the human race.
Born 25th Dec. 1648, died 20th March 1727.10
We cannot but feel struck, on reading this inscription, with the variety of talent, and depth, and universality of attainments, which it is intended to commemorate. Contemplating even now the efforts of his transcendent genius, we can scarcely tell what field of knowledge, human or divine, he has most assiduously cultivated. Independent of those greater productions of which a sketch has been attempted, his career was marked by a succession of brilliant discoveries, inferior in importance to these, yet many of them singly sufficient to immortalize his name; in some, descending from the higher walks of science, to illustrate its earliest principles; in others, he has soared beyond the spirit of his time in striking out new paths of inquiry, and anticipating the discoveries of a future age.
But the arena of his boldest triumphs was the science of Astronomy. In the very choice which thus directed his inquiries there was something most auspicious for his fame. Those bright and distant worlds, whose laws it was reserved for him to investigate, have ever been the objects of human curiosity. In their silent and eternal courses they have received the idolatry of a hundred generations. Through the annals of human superstition their influence has been ever predominant, presiding by some mysterious and fearful agency over the chances and calamities of life. That feeling of dread with which they were once regarded is past; a better philosophy has dispelled the terror, but it has not diminished the interest; it has taught us to consider them not as omnipotent over the fortunes and interest of earth, but as individually possessing an interest of their own, the abodes of other forms of organic life, of other orders of intelligent existence. Such are the prospects of modern astronomers: they are bold, yet scarcely conjectural. In the very circumstance of their being admissible, we recognise the sublimity of the science. There is a high and melancholy pleasure in reading, even on a monumental stone, the records of its great establisher, NEWTON.
The very pertinacity with which error retains its hold, is one of the strongest arguments for the final and eternal establishment of truth: it results from a natural fear, that in the wreck of received opinions, the very foundation of credibility should be destroyed, and mankind a second time involved in darkness and uncertainty. For this reason, perhaps, there have been few of ancient kingdoms, which have not bequeathed to other times, a faith, or a philosophy, more enduring than themselves. The Coliseum and the Acropolis are in ruins, but the philosophies which sprung up beneath their shadows are yet deep in the tide of human opinions, still influencing, with an unseen but mighty influence, the character of the age. The dark creed of the ancient Persian is yet descending from sire to son in the sacred annals of the Guebres; and the faith and fame of Zoroaster are yet triumphant against the desolation of his country, and the sword and the Koran of its Mahometan oppressors. But more especially is this truth to be observed in the records and remains of more ancient dynasties—in patriarchal Assyria—in sepulchral Egypt. The long succession of their kings and warriors is now doubtful or forgotten—the colossal relics of their primeval architecture are daily mouldering; but their sombre religion—their wild astrology, originating in the days of their greatness, are perpetuated when the very shadow of that greatness is no more. If, from the history of false and discarded systems, we may pass by analogy to the more enduring influence of truth, we shall perceive how high above the chances of time and vicissitude, the pedestal of Newton’s immortality is founded.
Among different nations, and in the succession of ages, the posthumous honours of genius have proportionally differed. There has been a period when the author of a “Principia” would have been deemed more than a mortal: that period of idolatry is past, and with it have passed the honours of its earth-born Divinities. We do not in this day consecrate the shrine or the temple in adoration of the dead; but the tribute which we now pay to the memory of Newton, shall be the tribute of all ages, and of climes—the admiration of his talents, and the imitation of his virtues!
It is now time that I should conclude. Perhaps I have erred, in reverting at such length on an evening of festivity to a theme of more solemn interest, the recollections of Newton. If the veneration which I bear for that great name has thus far misled me, I know I shall be forgiven; but I am encouraged to hope that the hour we have spent has not been wholly barren of instruction. The details of a sage’s history, no less than the productions of his retirement, are pregnant with golden wisdom; but it is that homely and practical wisdom, which is accessible to all its suitors. When this marble shall call up to our memories the career of Newton—his patient struggles, his eternal triumphs—it shall not be without a responsive chord from our own bosoms. If, in that silent admonition, one human spirit shall be awakened to its great duties, to suffer with fortitude, or triumph with humility, to expand with science, or warm with philanthropy, that marble shall not have left its native quarry in vain; but I am persuaded that this sacred influence will not be confined to an individual breast, but breathe into each of our bosoms; so shall we show more effectually than words can express our estimation of the value of the gift, and our gratitude to the noble giver; and I cannot but regard it as a most auspicious omen, when I see on this interesting occasion the distinguished representative of an illustrious house, cooperating heart and soul in that noblest work of British patriotism, the education, the enlightenment, and the happiness of his fellow countrymen.