Dr. BREWSTER'S Life of Newton, forming the Twenty-fourth Number of

the "Family Library," is the most creditable piece of biography which has for some time appeared in this country. The Life of Sir ISAAC NEWTON, like that of other philosophers, must necessarily consist chiefly of a history of the mind and the results of its exertions. Events and personal incidents can occupy but a small space in the history of a man who sits still all his life, and thinks. There are many men in this country well qualified to perform the task which Dr. BREWSTER has very ably executed; but it is scarcely creditable to us, that hitherto the only biography of this illustrious man that bore any pretensions to the name, was written by a French astronomer, M. BIOT ; whose very able work may be found in the columns of the Biographie Universelle. To that life, Dr. BREWSTER confesses his obligations ; and it has pro- bably furnished him with some valuable suggestions as to the form of his own work : it would, however, be the height of injustice to deny that Dr. BREWSTER'S Life is a wholly independent and ori- ginal undertaking, by a writer as well qualified as perhaps any man living to do entire justice to the subject.. The three great epochs of NEWTON'S life are the dates of his grand discoveries,--first, on Light ; second, on the system of Gra- vitation; third, the theory of Fluxion& The nature of discovery is such, and the peculiar manner in which NEWTON- held back his discoveries was so extraordinary, that a controversy which in- volved the republic of science, accompanied the announcement of all these sublime investigations•' more especially the first and third were attended by disputes and discussions which shook to its foundations the mathematical world. These controversies, which so implicate the fame of his subject, it becomes the duty of the biographer to analyze, estimate, and recount. This part, and one of the severest parts of his task, we are happy to say is exceedingly well performed ; unless, perhaps, it may be carried to somewhat too great an extent in the branch of the subject which may be supposed to be Dr. BREWSTER'S favourite from his own success in it,—namely, the experiments on Light. But assuredly we have but small reason for complaint on this head : when we see that the whole history of NEWTON'S life, private as well as scientific—an account of all his discoveries, of their nature, pro- gress, and value, together with a history _of the reception they met with in Europe, the controversies that ensued, and their final effect upon the state of science,—when we see all this, and much more, embraced in one duodecimo volume, at the price of five shillings, he must have a heart as iron as his countenance must be brazen who could turn round upon the author or the publisher with a grumble of discontent. NEWTON'S early propensity to scientific investigation, and his subsequent ardent pursuit of his mathematical studies at Cam- bridge, as well as the nature of his mild and amiable character, his philosophical temperament, and the facts of his high reputation and advancement in wealth and station during the latter half of his very long life, are circumstances well and popularly known. It is, however, only of late years, that a fact, or rather a rumour, has been published to the astonished world—that NEWTON, the calm, the philosophic, was at one period of his life insane. Nay, it has been maintained by the French mathematicians, by whom the question was first discussed, and who discovered a-part of the evidence on which it rests, that after this period of mental de- rangement, which took place about the forty-second year of his life, he never fully recovered his mental power ; that he never after- wards made another step in science ; and then only, in the decay and waste of his intellect, took to those theological pursuits in which he has undoubtedly not acquired the great name he won in the field of science. This most curious and interesting subject is discussed and examined at length by D;. BREWSTER; who, in his anxiety to confute the position of Bior and LA PLACES has hit upon several new facts relative. to NEWTON'S malady. Dr. BREW- STER has endeavoured 'to show, that what has been called insanity was only indigestion ;, that the intellect was never unsettled, Owe' the nerves were deranged ; and that, for a time, the tower of Wits in. a.StAte_ of unnatural irritobAhtlt. Viro: go, to ihr vritir the- Doctor as- to- believe- that l•Trarropr never was what is called insane : but it will be seen that his intellect was so far dis- ordered, that he did or wrote very absurd things, and did not afterwards recollect them. He complains of perpetual sleepless- ness—he does not get a quarter of an hour's repose in a fortnight, Sze. Medical men know that this is one of the first and surest symptoms of incipient insanity. It is not denied that all NEW- TON'S grand discoveries were made previous to this period, and that he afterwards felt some reluctance at venturing very deep into the minutia of his previous investigations. The story about the fire and the dog, Diamond, we believe to be some foolish anecdote which, whether true or false,. had no necessary connexion with NEWTON'S state of mind in 1693 and 1694, when he was, no doubt, labouring under disease of some kind or other, that more or less affected his conduct and temper. This disease may have been merely physical ; but, in a man of NEWTON'S abstemious and re- gular habits, at the close of a number of years of deep, intense, and anxious thought, it seems more probably to have been a reaction of the mind, after the exceeding, and we may say unnatural tension, at which it had been so long. kept. The whole history of these matters is to be found in the follow- ing extract ; the length of which must be pardoned for the sake of the great subject to which it refers, and the value of the new ma- terials first brought together by Dr. BREWSTER.

THE QUESTION OF SIR ISAAC NEWTON'S INSANITY DISCUSSED BY DR. BREWSTER.

"An event however occurred, which will ever form an epoch in his his- tory ; and it is a singular circumstance, that this incident has been for more than a century unknown to his own countrymen, and has been accident- ally brought to light by the examination of the manuscripts of Huygens. This event has been magnified into a temporary aberration of mind, which is said to have arisen from a cause scarcely adequate to its produc- tion.

"While he was attending divine service in a winter morning, be had left 'in his study a favourite little doc, called Diamond. Upon returning from chapel he found that it had overturned a lighted taper on his desk, which :bet fire to several papers on which he had recorded the results of some optical experiments. These papers are said to have contained the labours of many years ; and it has been stated, that when Mr. Newton perceived the magnitude of his loss, he exclaimed, Oh Diamond, Diamond, little do you know the mischief you have done me!' It is a curious circum- stance, that Newton never refers to the experiments which he is said to have lost on this occasion, and his nephew, Mr. Conduit, makes no allu- sion to the event itself. The distress' however, which it occasioned is said to have been so deep as to affect even the powers of his under- standing.

"This extraordinary effect was first communicated to the world in the life of Newton by M. Blot, who received the following account of it from the celebrated M. Van Swinden.

"'There is among the manuscripts of the celebrated Huygens, a small. journal in folio, in which he used to note down different occurrences. It is side, No. 8, p. 112, in the catalogue .of the library of Leyden. The following extract is writted by Huygens himself, with whose hand- writing I am well acquainted, having had occasion to peruse several of his manuscripts and autograph letters. "On the 29th May 1694, M. Colin,* a Scotsman, informed me, that 18 months ago, the illustrious geometer, rsaac Newton, had become insane, either cm consequence of his too intense application to his studies, or from excessive grief at haring lost, by fire, his chemical laboratory and several manuscripts. When he came to the Arch- • Irishop of Cambridge, he made some observations which indicated an aliena- tion of mind. He was immediately taken care of by his friends who confined him to his house and applied remedies, by Means of which he had now solar recovered his health that he began to understand the Principia."' Huygens mentioned this circumstance to Leibnitz in a letter dated 8th June 1694, to-which Leibnitz replies in a letter dated the 23rd, I am very glad that I received, information of the cure of Mr. Newton at the same time that I first heard of his illness which doubtless must have been very alarming. It is to men like-you and him, Sir, that I wish a long life."

"The first publication of the preceding statement produced a strong sensation amorit the friends and admirers of Newton. They could not easily believe' in the prostration of that intellectual strength which had unbarred the strongholds of the universe. The unbroken equanimity of Newton's mind, the purity of his moral character, his temperate and ab- stemious life, his ardent and Unaffected piety, and the weakness of his imaginative powers, all indicated a mind which was not-likely to be over- set by any affliction to which it could .be exposed. The loss of a few ex- perimental records could never have disturbed the equilibrium of a mind like his. If they were the records of discoveries, the discoveries, them- selves indestructible, would have been afterwards given to the world. If they were merely the details of experimental results, a little time could have easily reproduced them. Had these records contained the first fruits of early genius—cif obscure talent, on which fame had not yet shed its rays, we might- have supposed that the first blight of such early ambition Would have unsettled the stability of an untried mind. But Newton was -satiated with fame. His mightiest discoveries were completed, and dif- fused over all Egrope, and he-must have felt himself, placed on the loftiest ,pinnacle of earthly ambition. The incredulity which such views could not fail to encourage, was increased by. the novelty of the information. No English biographer had ever alluded to such an event. History and 'tradition were equally silent ; and it was not easy to believe that the lucasian Professor of Mathematics at Cambridge, a member of the Eng- lish Parliament, and the first philosopher in 'Earope„could have lost his :reason without the dreadful fact being known to -his own countrymen. ' But if the friendi of Newton were surprised:by the natufE of the in- telligence; they were distressed- at the view which was taken of it by foreign philosophers. - :While one maintained that the intellectual exer- tions of Newton had terminated with the publication of the Principle, and that the derangement- of his mind was the cause Of his abandoning the sciences, others indirectly questioned. the sincerity of his religious views, and ascribed to the aberration-of his -Mind those theological pur- suits which gilded his declining age: But the-fact,' says M. Blot, of the derangement of his: intellect, whatever may. haye: been the muse of it, • of This N. Colin was probably n young Bachelor of Arta whom Newton seems afterwards to have employed in some of his calculations. These bachelors were distIn- guished by the title of Domints and it was,usual to-translate this word and to call them. Sir. In nletter from Newton-to Flaznstead, dated Cambridge, 29th June is the following passage : want not yaw calculations but, your observa- tions only, for besides myself, antrity servant, Sir Collins (whom I can employ-for a little money, which lyitlue riot); teas trze-thnt,he can calculate an eutipse.auci work truly.'" will explain why, after the publication of the-Principia in 1687, Newton-4 though only forty-five years old, never more published' a new work on‘

any branch of science, but contented himself with -giving to the world'

those which he had composed long before that epoch, confining himself' to the completion of those parts which might require development. We.

may also remark, that even these developments appear always to be de-. rived from experiments and observations formerly made, such as the additions to the second edition of the Principia, published in 1713, the

experiments on thick plates,those on diffraction, and the chemical queries placed at the end of the Optics in 1704; for in giving an account of these experiments Newton distinctly says, that they were taken from ancient manuscripts which he had formerly composed ; and headds, that though. he felt the necessity of extending them, or rendering them more perfect, he was not able to resolve to do this these matters being no longer in his way. Thus it appears, that though he had recovered his health sufficiently to understand all his researches, and even in some cases to. make additions to them, and useful alterations, as appears from the se- cond edition of the Principia, for which he kept up a very active mathe- matical correspondence with Mr. Cotes, yet he did not wish to under- take new labours in those departments of science where he had done so much, and where he so distinctly saw what remained to be done.' Under the influence of the same opinion M. Biot finds it extremely probable- that his dissertation on the scale Of heat was written before the fire in his- laboratory ;' he describes Newton's conduct about the longitude bill as almost puerile on so solemn an occasion, and one which might lead to the strangest conclusions, particularly if we refer it to the fatal accident which Newton had suffered in 1695.'

" The celebrated Marquis de la Place viewed the illness of Newton in a light still more painful to his friends. He maintained that he never re-- covered the vigour of his intellect, and he was persaded that Newton's theological inquiries did not commence till after that afflicting epoch of his life. He even commissioned Professor Gautier of Geneva to make inquiries on this subject during his visit to England, as if it concerned, the interests of trutlrandjustice to show that Newton became a Christian- and a theological writer, only after the decay of his strength and the eclipse of his reason. " Such having been the consequences of the disclosure of Newton's i& ness.by the manuscript of Huygens, I felt it to be a sacred duty to the memory of that great man, to the feelings of his countrymen, and to the interests of Christianity itself, to inquire into the nature and history-of. that indisposition which seems to have been so much misrepresented and misapplied. From the ignorance of so extraordinary an event which has prevailed for such a long period in England, it might have been urged with some plausibility, that Huygens had mistaken the real import of the information that was conveyed to him ; or thatthe Scotebrnan from whom he received it had propagated an idle and a groundless rumour: But we are fortunately not confined to this very reasonable mode of defence. There exists at Cambridge a manuscript journal written by Mr. Abraham. de la Pryme, who was a student in the University while Newton was a- fellow of Trinity. This manuscript is entitled Ephemeris Vita% or Diary of my own Life, containing an account likewise of the most observable; and remarkable things that I have taken notice of from my youth up - hitherto.' Mr. de la Fume was born in 1671, and begins the diary in- 1685. This manuscript is in the possession of his collateral descendant, George Pryme, Esq. Professor of Political Economy at Cambridge, to whom I have been indebted for the following extract. " 1692, February 3rd.—What I heard to-day I must relate. There is. one Mr. Newton (whom I have very oft seen), Fellow of Trinity College, that is mighty famous for his learning, being a most excellent matilema.-. tician, philosopher, divine, &c. He has been Fellow of the Royal So- ciety these many years ; and amongst other very learned books and tracts _ he's written one upon the mathematical principles of philosophy, which has got him a mighty name, he having received, especially from Scotland, abundance of congratulatory letters for the same ; but of all the books that he ever wrote, there was one of colours and light, established upon, thousands of experiments which he had been twenty years of making,. and which had cost him many hundred of pounds. This book, which he valued so much, and which was so much talked of, had the ill luck to perish, and be utterly lost, just when the learned author was almost at putting a conclusion at the same, after this manner: In a winter's morn- ing, leaving it amongst his other papers on his study-table whilst he went to chapel, the candle, which he had unfortunately left burning there tic), catched hold by some means of other papers, and they fired the aforesaid book, and utterly consumed it and several other valuable writings; and which is most wonderful, did no further mischief. But when Mr. New- ton came from chapel, and had seen what was done, every one thought he would have run mad, he was so troubled thereat, that he was not himself for a month after. Along account of this his system of light and colours you may find in the Transactions of the Royal Society, which he had sent up to them iong before this sad mischance happened unto. him.'

"From this extract we are enabled to fix the approximate date of the accident by. which Newton lost his papers. It must have been previous to the 3rd January 1692, a month before the date of the extract; but M we fix it by the dates in Huygens's manuscript, we should place it- about the 29th November 1692, eighteen months previous to the con- versation between Collins and Huygens. The manner in which Mr. Pryme refers to Newton's state of mind is that which is used every day: when we speak of the loss of tranquillity which arises from the ordinary afflictions of life ; and the meaning of the passage amounts to nothing- more than that Newton was very much troubled by the destruction of his papers, and did not recover his serenity, and return to his usual occu- pations, for a month. The very phrase, that every person thought he would have run mad, is in itself a proof that no such effect was produced; and, whatever degree of indisposition may be implied in the phrase, he was not himself for a month after,' we are entitled to inger that one- month was the period of its duration, -and that previous to the 3rd Fe- bruary 1692, the date of Mr. Pryme's memorandum, Newton was him.- self again.' "These facts and dates cannot be reconciled with those in Hoygens's: manuscript. It appears from that document, that, so late as May 1694,, Newton had only so far recovered his health as to begin to again under- stand the Principia. His supposed malady, therefore, was in force from

the 3rd of January 1692, till the month of May I694—a period of more i - than two years. Now, t is a most important circumstance, which

Blot ought to have known, that in the very middle of this period, Newton wrote his four celebrated letters to Dr. Bentley on the Existence of s.: Deity,—letters which evince a power a thought and a serenity_of M absolutely incompatible even with the slightest obscuration of his Ise ties. No man can peruse these letters without the conviction that their a.uthorithen possessed the full 'vigour of his reason,, and. was capable Og. understanding the most profs:lurid part* of his wrinngs. The first of these 1etter4 was W3Itten on the 10.1,b. December 1M, the second oil tbeflUb

throw much light upon the subject. mitted to his judgment.* more explicit letter to his friend Mr. Millington— and consequently during the illness under which he then laboured.

" ' 26th September 1693. " ' SIR—Being of opinion that you endeavoured to embroil me with wo- " 'SIR—After acknowledging your many old favours, give me leave to men, and by other means, I was so much affected with it, as that when do it a little more particularly upon occasion of the new one con- one told me you were sickly and would not live, I answered, 'twere better veyed to me by my nephew Jackson. Though, at the same time, I must if you were dead. I desire you to forgive me this uncharitableness ; for acknowledge myself not at the ease I would be glad to be at in reference I am now satisfied that what you have done is just, and I beg your pardon to the excellent Mr. Newton ; concerning whom (methinks) your answer for my having hard thoughts of you for it, and for representing that you labours under the same kind of restraint which (to tell you the truth) my struck at the root of morality, in a principle you laid in your book of asking did. For I was loth at first dash to tell you that I had lately received ideas, and designed to pursue in another book, and that I took you for a a letter from him so surprising to me for the inconsistency of every part Hobbist.t I beg your pardon also for saying or thinking that there was a of it, as to be put into great disorder by it, from the concernment I have design to sell me an office, or to embroil me.—I am your most humble for him, lest it should arise from that, which of all mankind I should least and unfortunate servant, Is. NEWTON.' dread from him and most lament for,—I mean a discomposure in head, "At the Bull, in Shoredltch, London, September 16th 1693.' or mind, or both. Let me therefore beg you, Sir, having now told you "To this letter Locke returned the following answer, so nobly dist in- the true ground of the trouble I lately gave you, to let mjknow the very guished by philosophical magnanimity and Christian charity— truth of the matter, as far, at least, as comes within your knowledge. " ' Oates, 5th October 1693.

For I own too great an esteem for Mr. Newton, as for a public good, to " ' SIR—I have been, ever since I first knew you so entirely and sin be able to let any doubt in me of this kind concerning him lie a moment cerely your friend, and thought you so much mine, that I could not have uncleared, where 1 can have any hopes of helping it. I am, with great believed what you tell me of yourself, had I had it from any body else. truth and respect, dear Sir, your most humble and most affectionate And, though I cannot but be mightily troubled that you should. have had servant, S. PEPTS? so many wrong and unjust thoughts of me, yet next to the return of " HONOR'D SIR—Coming home from a journey on the 28th instant at done me, since it gives me hopes I have not lost a friend I so much valued. night, I met with your letter which you were pleased to honour me with After what your letter expresses, I shall not need to say any thing to jus- of the 26th. I am much troubled I was not at home in time for the post, tify myself to you. I shall always think your own reflection on my car- that I might as soon as possible put you out of your generous payne riage, both to you and all mankind, will sufficiently do that. Instead of that you are in for the worthy Mr. Newton. I was, I must confess, very that, give me leave to assure you that I am more ready to forgive you much surprised at the inquiry you were pleased to make by your nephew

about the message that Mr. Newton made the ground of his letter to you, than you can be to desire it ; and I do it so freely and fully, that I wish for I was very sure I never either received from you or delivered to him for nothing more than the opportunity to convince you that I truly love of this had happened. To confirm this to you more fully, I should be any such ; and therefore I went immediately to wayt upon him, with ft and esteem you, and that I have the same good will for you as if nothing design to discourse him about the matter, but he was out of town, and glad to meet you anywhere, and the rather, because the conclusion of since I have not seen him, till upon the 28th I met him at Huntingdon, your letter makes me apprehend it would not be wholly useless to you. where, upon his own accord, and before I had time to ask him any ques- But whether you think it fit or n

tion, he told me that he had writt to you a very odd letter, at which he not, I leave wholly to you. I shall always shall was much concerned ; added, that it was in a distemper that much seized be ready to serve you to my utmost, in any way you shall like, and sha his head, and that kept him awake for above five nights together, which only need your commands or permission to do it.

occasion he desired I would represent to you, and beg your pardon, answer for the design with which I write it, yet, since you have so oppor- tunely given me notice of what you have said of it, I should take it as a " ' My book is going to press for a second edition ; and, though I can- upon ocche being very mucla,ashamed he should be so rude to a person for whom

he hath so great an honour. He is now very well, and, though I fear he

is under some small degree of melancholy, yet I think there is no reason favour if you would point out to me the places that gave occasion to that to suspect it hath at all touched his understanding, and I hope never censure, that, by explaining myself better, I may avoid being mistaken by others, or unawares doing the least prejudice to truth or virtue. I am 'will; and so I am sure all ought to wish that love learning or the honour of our nation, which it is a sign how much it is looked after, when such a sure you are so much a friend to them both, that, were you none to me, L person as Mr. Newton lye: so neglected by those in power. And thus, could expect this from you. But I cannot doubt but you would do a honoured Sir, I have made you acquainted with all I know of the cause of great deal more than this for my sake, who, after all, have all the con- such inconsistencys in the letter of so excellent a person ; and I hope it ern of a friend for you, wish you extremely well, and am, without cora-,

will remove the doubts and fears you are, with so much compassion and publickness of spirit, pleased to entertain about Mr. Newton ; but if I " To this letter Newton made the following reply :—

should have been wanting in any thing tending to the more full satisfac- " ' Cambridge, 5th October 1693.. tion, I shall, upon the least notice, endeavour to amend it with all grati- " 4 SIR—The last winter, by sleeping too often by my fire, I got an ill tude and truth. Honored Sir, your most faithfull and most obedient ser- habit of sleeping; and a distemper, which this summer has been epi- want, JOH. MILLINGTON? • "These three letters have been published by Lord Braybrooke in the Life and. "Mr. Pepys was perfectly satisfied with this answer, as appears from Correspondence of Mr. Pepys." following letter. t "This anxiety will beunderstoodfrom:the fact, that by an orderiof council, dated the fo

• "They are tints dated In tforsley's edition of Newton's Works,thefouraletter one shilling per week,' on account of his low circumstances, as he represented.'

having an earlier date than the third. : The system of Hobbes was at this time very prevalent. According to Dr. Bent.- t "See Newtont Opera, tome iv. p.480 ; .and Wallisii Opera, 1693, tome ii. p. 391- 2196. ley, "The taverns and coffeehouses, nay Westminster Hall, and the very churches,. s "Optics, Part iv. Ohs. 13. English infidel in a hundred was other than a Hobbist."—MonkitLife of Bentley,. s "For these letters I have been indebted to the kindness of Lord Braybrooke. • The draught of this letter is indorsed" J. L. to I. Newton." January 1693, the third on the 25th February, and the fourth on the " ' 3rd October 1693.

Ilth • February 1693. His mind was, therefore, strong and vigorous on " ' SIR—You have delivered me from a fear that indeed gave me much

these four occasions; and as the letters were written at the express re- trouble, and from my very heart I thank you for it, an evil to Mr. Newton quest of Dr. Bentley, who had been appointed to deliver the lecture being what every good man must feel for his own sake as well as his. God founded by Mr. Boyle for vindicating the fundamental principles of na- grant it may stopp here. And for the kind reflection bee has since made- tural and revealed religion, we must consider such a request as showing upon his letter to mee, I dare not take upon mee to judge what answer 1

his opinion of the strength and freshness of his friend's mental powers. should make him to it, or whether any or no ; and therefore pray that you " In 1692, Newton, at the request of Dr. Wallis, transmitted to him the will bee pleased either to bestow on mee what directions you see fitt for first proposition of his book on quadratures, with examples of it in first, my own guidance towards him in it, or to say to him in my name, but second, and third fluxions.t These examples were written in conse- your own pleasure, whatever you think may be most welcome to him upon quence of an application from his friend ; and the author of thesreview it and most expressive of my regard and affectionate esteem of him, and of the Commercium Epistolicum, in which this fact is quoted, draws the concernment for him. • • • • Dear Sir, your most humble and most conclusion, that he had not at that time forgotten his method of second faithful servant, S. PEPYS? fiuxions. It appears, also, from the second book of the Optics, : that in " It does not appear, from the memoirs of Mr. Pepys, whether he ever the month of June 1692 he had been occupied with the subject of haloes, returned any answer to the letter of Mr. Newton which occasioned this and had made accurate observations both on the colours and the diame- correspondence ; but we find that in less than two months after the date ters of the rings in a halo which he had then seen around the sun. of the preceding letter, an opportunity occurred of introducing to him a

" But though these facts stand in direct contradiction to the statement Mr. Smith, who wished to have his opinion on some problem in the doe- recorded by Huygens, the reader will be naturally anxious to know the trine of chances. This letter from Pepys is dated 22nd November 1693. real nature and extent of the indisposition to which it refers. The fol- Sir Isaac replied to it on the 26th of November, and wrote to Pepys again lowing letters, written by Newton himself, Mr. Pepys, Secretary to the on the 16th of December 1693 ; and in both these letters he enters fully Admiralty, and Mr. Millington, of Magdalene College, Cambridge, will into the discussion of the mathematical question which had been sub-

" Newton, as will bepresently seen, had fallen into a bad state of health " It is obvious from Newton's letter to Mr. Pepys, that the subject of some time in 1692, in consequence of which both his sleep and his appe- his receiving some favour from the government had been a matter of tite were greatly affected. About the middle of September 1693, he had anxiety with himself, and of discussion among his friends.1- Mr. Mil- been kept awake for five nights by this nervous disorder, and in this con- lington was no doubt referring to this anxiety, when he represents New- dition he wrote the following letter to Mr. Pepys. ton as an honour to the nation, and expresses his surprise ' that such a

" ' 13th September 1693. person should lye so neglected by those in power.' And we find the same sub- " ' SIR—Some time after Mr. Millington had delivered your message, he ject distinctly referred to in two letters written to Mr. Locke during the pressed me to see you the next time I went to London. I was averse ; preceding year. In one of these, dated January 26th 1691-2, he says, but upon his pressing, consented, before I considered what I did, for I ' Being fully convinced that Mr. Montague, upon an old grudge which I am extremely troubled at the embroilment I am in, and have neither ate thought had been worn out, is false to me, I have done with him, and in- nor slept well this twelvemonth, nor have my former consistency of tend to sit still, unless my Lord Monmouth be still my friend.' Mr. mind. I never designed to get any thing by your interest, nor by King Locke seems to have assured him of the continued friendship of this no. James's favour, but am now sensible that I must withdraw from your ac- bleman, and Mr. Newton, still referring to the same topic, in a letter quaintance, and see neither you nor the rest of my friends any more, if I dated February 16th 1691-2, remarks, ' I am very glad Lord Monmouth is may but leave them quietly. I beg your pardon for saying I would see still my friend, but intend not to give his Lordship and you any farther

you again, and rest your most humble and most obedient servant, trouble. My inclinations are to sit still.' In a later letter to Mr. Locke, dated " ' Is. NEWTON.' September 1693, and given in the following page, he asks his pardon for

" From this letter we learn, on his own authority, that his complaint saying or thinking that there was a design to sell him an office. In these had lasted for a twelvemonth, and that during that twelvemonth he nei- letters Mr. Newton no doubt referred to some appointment in London ther ate nor slept well nor enjoyed his former consistency of mind. It is which he was solicitous to obtain, and which Mr. Montague and his other not easy to understand exactly what is meant by not enjoying his former friends may have failed in procuring. This opinion is confirmed by the consistency of mind ; but whatever be its import, it is obvious that he letter of Mr. Montague, announcing to him his appointment to the War- must have been in a state of mind so sound as to enable him to compose denship of the Mint, in which he says that he is very glad he can at last the four letters to Bentley, all of which were written during the twelve- give him good proof of his friendship.

month here referred to. " In the same month in which Newton wrote to Mr. Pepys, we find him

" On the receipt of this letter, his friend Mr. Pepys seems to have writ- in correspondence with Mr. Locke. Displeased with his opinions respect- ten to Mr. Millington of Magdalene College, to inquire after Mr. New- ing innate ideas, he had rashly stated that they struck at the root of all ton's health ; hut the inquiry having been made in a vague manner, an morality; and that he regarded the author of such doctrines as a Hob- answer equally vague was returned. t'Mr. Pepys, however, who seems to bist. Upon reconsidering these opinions, he addressed the following re. have been deeply anxious about Newton's health, addressed the following markable letter to Locke, written three days after his letter to Mr. Pepys, " ' 26th September 1693. " ' SIR—Being of opinion that you endeavoured to embroil me with wo- " 'SIR—After acknowledging your many old favours, give me leave to men, and by other means, I was so much affected with it, as that when do it a little more particularly upon occasion of the new one con- one told me you were sickly and would not live, I answered, 'twere better veyed to me by my nephew Jackson. Though, at the same time, I must if you were dead. I desire you to forgive me this uncharitableness ; for acknowledge myself not at the ease I would be glad to be at in reference I am now satisfied that what you have done is just, and I beg your pardon to the excellent Mr. Newton ; concerning whom (methinks) your answer for my having hard thoughts of you for it, and for representing that you labours under the same kind of restraint which (to tell you the truth) my struck at the root of morality, in a principle you laid in your book of asking did. For I was loth at first dash to tell you that I had lately received ideas, and designed to pursue in another book, and that I took you for a a letter from him so surprising to me for the inconsistency of every part Hobbist.t I beg your pardon also for saying or thinking that there was a of it, as to be put into great disorder by it, from the concernment I have design to sell me an office, or to embroil me.—I am your most humble

" To this letter Mr. Millington made the following reply— good offices, such as from a sincere good will I have ever done you, I re-

"' Coll. Magd. Comb. September the 30 1693. ceive your acknowledgment of the contrary as the kindest thing you have

pliment, &c.' * 28th January 1674-5, Mr. Newton was excused from making the usual payments of

were full of it ;" and he was convinced, from personal observation, that "not one- demical, put me farther out-of order, so that when I wrote to you, I had not slept an hour a night for a fortnight together, and for five days to- gether not a wink. I remember I wrote to you, but what I said of your book I remember not. If you please to send me a transcript of that passage, I will give you an account of it if I can.—I am your most humble servant, Is. NEWTON.'

" Although the first of these letters evinces the existence of a nervous irritability which could not fail to arise from want of appetite and of rest, yet it is obvious that its author was in the full possession of his mental powers. The answer of Mr. Locke, indeed, is written upon that suppo- sition ; and it deserves to be remarked, that Mr. Dugald Stewart, who first published a portion of these letters, never imagines for a moment that Newton was labouring under any mental alienation. " The opinion entertained by La Place, that Newton devoted his atten- tion to theology only in the latter part of his life, may be considered as deriving some countenance from the fact, that the celebrated general scholium, at the end of the second edition of the Principle, published in 1713, did not appear in the first edition of that work. This argument has been ably controverted by Dr. J. C. Gregory of Edinburgh, on the autho- rity of a manuscript of Newton, which seems to have been transmitted to his ancestor, Dr. David Gregory, between the years 1687 and 1698. This manuscript, which consists of twelve folio pages in Newton's hand- writing, contains, in the form of additions, and scholia to some propo- sitions in the third book of the Principia, an account of the opinions of the ancient philosophers on gravitation and motion, and on natural theo. logy, with various quotations from their works. Attached to this manu- script are three very curious paragraphs. The two first appear to have been the original draught of the general scholium already referred to ; and the third relates to the subject of an ethereal medium, respecting which he maintains an opinion diametrically opposite to that which he afterwards published at the end of his Optics.t The first paragraph ex- presses nearly the same idea as some sentences in the scholium beginning 'Dens summus est ens mternum, infinitum, absolute perfectum ;' and it is remarkable that the second paragraph is found only in the third edi- tion of the Principle, which appeared in 1726, the year before Newton's death.

"In the middle of the year 1694, about the time when our author is said to be beeinning to understand the Principia, we find him occupied with the difficult and profound subject of the lunar theory. In order to procure observations for verifying the equations which he had deduced from the theory of gravity, he paid a visit to Flamstead, at the Royal Observatory of Greenwich, on the 1st September 1694, when he re- ceived from him a series of lunar observations. On the 7th of October he wrote to Flamstead that he had compared the observations with his theory, and had satisfied himself that by both together 'the moon's theory may be reduced to a good degree of exactness, perhaps to the ex- actness of two or three minutes.' He wrote him again on the 24th Oc- tober, and the correspondence was continued till 1698, Newton making constant application for observations to compare with his theory of the planetary motions ; while Flamstead, not sufficiently aware of the im- portance of the inquiry, received his requests as if they were idle intru- sions in which the interests of science were but slightly concerned.

"In reviewing the details which we have now given respecting the health and occupations of Newton from the beginning of 1692 till 1695, it is im- possible to draw any other conclusion than that he possessed a sound wind, and was perfectly capable of carrying on his mathematical, his metaphysical, and his astronomical inquiries. His friend and admirer, Mr. Pepys, residing within fifty miles of Cambridge, had never heard of Ms being attacked with any illness till he inferred it from the letter to himself written in September 1693. Mr. Millington, who lived in the same University, had been equally unacquainted with any such attack, and, after a personal interview with Newton, for the express purpose of ascertaining the state of his health, he assures Mr. Pepys 'that he is very well,—that he fears he is under some small degree of melancholy, but that there is no reason to suspect that it hath at all touched his under- standing.'

"During this period of bodily indisposition, his mind, though in a state of nervous irritability, and disturbed by want of rest, was capable of putting forth its highest powers. At the request of Dr. Wallis be drew up an example of one of his propositions on the quadrature of curves in second fluxions. He composed, at the desire of Dr. Bentley, his profound and beautiful letters on the existence of the Deity. He was requested by Locke to reconsider his opinions on the subject of innate ideas, and we find him grappling with the difficulties of the lunar theory.

"But with all these proofs of a vigorous mind, a diminution of his mental powers has been rashly inferred from the cessation of his great discoveries, and from his unwillingness to enter upon new investigations. The facts, however, here assumed, are as incorrect as the inference which is drawn from them. The ambition of fame is a youthful passion, which is softened, if not subdued by age. Success diminishes its ardour, and early preeminence often extinguishes it. Before the middle period of his life, Newton was invested with all the insignia of immortality; but endowed with a native humility of mind, and animated with those hopes which teach us to form a humble estimate of human greatness, he was satisfied with the laurels which he had won, and he sought only to perfect and complete his labours. His mind was principally bent on the im- provement of the Principia; but he occasionally diverged into new fields of scientific research,—he solved problems of great difficulty which had been proposed to try his strength,—and he devoted much of his time to profound inquiries in chronology and in theological literature.

"The powers of his mind were therefore in full requisition ; and, when we consider that he was called to the discharge of high official functions which forced him into public life, and compelled him to direct his genius into new channels, we can scarcely be surprised that he ceased to produce any original works on abstract science. In the direction of the affairs of the Mint and of the Royal Society, to which we shall now follow him, he found ample occupation for his time; while the leisure of his declining years was devoted to those exalted studies in which philosophy yields to the supremacy of faith, and hope administers to the aspirations of genius."

t Dr. Gregory concludes his account of this manuscript, which he has kindly permitted me to read, in the following words:—" I do not know whether it is true, as stated by Huygens, Newtonum incidisse in Phrenitim but I think every gen- tleman who examines this manuscript will be of opinion that he must have tho- roughly recovered from his phrenitis before he wrote either the Commentary on the Opinions of the Ancients, or the Sketch of his own Theological and Philosophical Opinions, which it contains."