Upminster ☿ 18 Iul: 1733.

HondHonoured SrSir

According to your desire, I here send you some matters relating to my excellent Friend SrSir Is:Isaac Newton: wchwhich you should have had sooner, but I have not been long in this place, where my Memorials are; & have ever since I came been so afflicted wthwith the Colick, ytthat I was not able to dispatch any considerable business.

I had the HonrHonour & Happiness of SrSir Isaac's Acquaintance about 30 years. And by our frequent Conversation (for the most part about Philosophical matters) had opportunites of discerning his great Genius, & admirable Parts Of wchwhich he hath given the learned World abundant Proof in his Works(2)Works: in wchwhich he hath shewed his Acumen & Penetration to be equal, if not superior, to ytthat of Archimedes, Euclid, & other the greatest Wits of former Ages.

One great sign of wchwhich, may be the Ambition wchwhich some of the greatest Genij of SrSir Isaac's time, had, of robbing him of some of his Inventions. Of wchwhich I shall instance in two, because I had some concern in them.

The first is the Controversy wchwhich SrSir Isaac had wthwith Mr. Leibnitz. Which affair was transacted in the Royal Society whilst I had the HonrHonour to be one of the Council of thereof, & produced some Original Letters ytthat I found among the Papers of Rich.Richard Townley EsqrEsquire (now in my hands) wchwhich plainly demonstrate SrSir Isaac's just Title to wtwhat he claims. Which Letters being (as far as relates(3)relates to this Controversy) published in the Com̄mmercium Epistolicum, I shall give no account of: only I think fit to cite, in his own words ytthat wchwhich Mr Collins writes to Mr Strode, viz. Mr Newton & Mr Gregory intend to write of this Method in Latin: but Mr Gregory will not anticipate Mr Newton, the first Inventor thereof Vid. Com̄mmerc. Epist.Commercium Epistolicum p. 29.

When SrSir Is:Isaac & I discoursed about these matters, he gave me this short History of them, viz. That when he was a Iunior at the University, he had thoughts of these things, but brought them to no perfection, by reason he was forced to leave the University in the Plague-year 1665 & 1666. But at his return to Cambridge, Mercator's Logarithmotechia, & what Dr Wallis published about ytthat time, revived his his thoughts of these matters, and then(4)then he brought them to more perfection, & Com̄mmunicated them to Dr Barrow, at ytthat time of the same College, who approving of them, acquainted Mr Collins & other wthwith them. Thus far SrSir Isaac.

Mr Collins (a man born to promote Mathematicks) I find was so taken wthwith SrSir Isaac's Discovery, ytthat he wrote to divers persons about it in 1669, 1670, &c, as appears by his LrsLettters in my hands.

How Mr Leibnitz came to be informed of SrSir Isaac's Method, & afterwards to dress it up with different Terms, & claim it as his own, SrSir Is–Isaac always spake wthwith great modesty, with relation to himself, & great honour & regard to the excellent Parts and Capacity of Mr. Leibnitz. He thought it probable(5)probable ytthat when Mr Leibnitz was in England in the years 1673 & 1676, he might get information of a matter talked of, in his own way, among the Mathematicians, or ytthat his Countryman Mr Oldenburgh might give him information of it But how so great a Genius as Mr Leibnitz came to dresse it up in different colours, & publish it as his own, SrSir Is.Isaac left to the judgment of others.

The other thing wchwhich I said was claimed, was by Dr Hook, & was no lesse a matter than SrSir Isaac's Doctrine of the Mundane Systeme. This happened to come into our discours, as Dr Hook and I were discoursing talking about Mr Huygens's celebrated Watch, & the Doctor's Inventions in Watchwork. At which(6)which time the DrDoctor took occasion to tell me, ytthat he had discovered the reciprocal Gravitation of the Planets &c, long before SrSir Is:Isaac Newton, & complained to me of the injury SrSir Is:Isaac had done him in robbing him of the Invention. This I thought my self bound, by the Rules of Friendship, to acquaint SrSir Is:Isaac with. To wchwhich he (wthwith greater warmth & peevishness than was usual in him) gave me this Answer, That he believed Dr Hook could not perform ytthat wchwhich he pretended to: let him give Demonstrations of it: I know he hath not Geometry enough to do it. I confess I was surprized at this Answer, knowing Dr Hook to be a very considerable man. But by Letters I find among Dr Hooks Papers (wchwhich are now in(7)in my hands) I perceive ytthat this matter was controverted, & SrSir Is:Isaac teized about the year 1686. In a Letter of SrSir Is:Sir to Dr Halley of Iun. 20. 1686, he says In one of my Papers written above 15 years agoe, the Proportion of the Forces of the Planets from the Sun reciprocally duplicate of to their Distances from the Sun him, is exprest: & the Proportion of our Gravity to the Moon's Conatus recedendi a centro terræ is calculated, though not accurately ennough. And in another LrLetter of this same date, SrSir Is:Isaac says he wrote a LrLetter of Thanks to Hugenius for the his Present of his Horologium Oscillatorium, & directed it to Mr Oldenburgh, who used to keep the Originals, & his Papers coming into Mr Hook's hands, he might have(8)have the curiosity to look into ytthat LrLetter, and thence take the Notion of comparing yethe Forces of the Planets arising from their ciruclar motion; & so what he wrote to me afterwards about the Ratio of Gravity, might be nothing but the Pursuit of my own Garden. And in another LrLetter of Iul. 27. 1686. SrSir Isaac speaking of a LrLetter of his, part of wchwhich, about Colours, was published in Phil: Trans:Philosophical Transactions Nr 96. saith, It is evident from wtwhat I is said there, ytthat I was at ytthat time versed in the Theory of the Forces arising from Circular Motions, & had an eye upon the Forces of the Planets, knowing how to compare them by the Proportions of their Periodical Revolutions Distances from the Center they move about: An instance of wchwhich you have here(9) here in the comparison of the Forces of the Moon arising from her menstrual Motion about the Earth, and annual about the Sun. So then in this Theory I am plainly before Mr Hook. For he about a year after, in his Attempt to prove the Motion of the Earth, declared expresly that the Degrees by wchwhich Gravity decreased, he had not then experimentally verified, ytthat is, He knew not how to gather it from Phænomena, & therefore recom̄mmends it to the prosecution of others. Thus much I find in the Papers remaining in the my hands: but more is in some of the DrDoctor's Papers, wchwhich I delivered up some time since to the R.Royal Society.

The next Remark I shall make shall be of a somewhat out of the way Proof of God, wchwhich SrSir Isaac mentioned in some discourse

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These Controversies wthwith Leibnitz, Hooke, & Linus, & others about Colours, made SrSir Is:Isaac very uneasy; who abhorred all Contests, accounting Peace a substantial Good. And for this reason, namely to avoid being baited by little smatterers in Mathematicks, he told me, he designedly made his Principia abstruse; but yet so as to be understood by able Mathematicians, who he imagined, by comprehending his Demonstrations, would concurr wthwith him in his Theory.

The next Remark I shall make shall be a peculiar sort of Proof of God, wchwhich SrSir Is:Isaac mentioned in some discourse wchwhich he & I had soon after I published my Astro-Theology. He said there were 3 things in the Motions of the Heavenly Bodies, ytthat were plain Evidences(101)ces of Omnipotence & wise Counsel: 1. That the Motion imprest upon these Globes was Lateral, or in a Direction perpendicular to their Radij, not along them or parallel wthwith them. 2. That the motions of them tend the same way. 3 That their Orbits have all the same, or nearly the same Inclination.

As SrSir Is:Isaac Newton was well skilled in Chymistry, & particularly had made divers trials on the Fusion of Metals for Reflecting Telescopes, so I think some of his Observations on this subject worth your Cognizance, SrSir. He told me, If the Block-Tin is put into the Crucible to be melted with the Copper, ytthat the greater part will thereof will be evaporated; & therefore ought not to be put in untill the Copper is melted. Also if the Tin is too hot, & boyls, it makes the Metal porous. Therefore he advised, when(12) when the Tin is put in to the melted Copper, and is it self melted, ytthat it should be stirred two or three times wthwith the Spatula, & suddainly poured into the Mold: & ytthat the cooler & thicker the Melted Metal is, whien run into the Mold, so much the better it is, than when too hot & thin.

The last thing, SrSir, ytthat I shall trouble you with, shall be a Passage relating to the Coynage of the Copper-money some years agoe, wchwhich pleased me much, as setting forth the Integrity of my Friend, SrSir IsIsaac. The occasion of our Discourse was, The great inconveniences which many underwent by the Delay of the Coynage of this sort of Money. The occasion of which Delay, SrSir Is:Isaac told me, was from the numerous Petitions ytthat were presented then; in most of wchwhich some person or other of Quality was concerned. Amongst others he told me, ytthat an Agent of one had(13) had made him an Offer of above 6000 lipounds. WchWhich SrSir Is:Isaac refusing on account of its being a Bribe; the Agent said, he saw no dishonesty in the acceptance of the Offer & ytthat SrSir Is:Isaac understood not his own Interest. To wchwhich SrSir Is:Isaac replied ytthat he knew well enough wtwhat was his Duty, & ytthat no Bribes should corrupt him. The Agent then told him ytthat he came from a great Dutchesse, & pleaded her Quality & Interest. To wchwhich SrSir Is:Isaac roughly answered, I desire you to tell the Lady, ytthat if she was here her self, & had made me the Offer, I would have desired her to go out of my house, & so I desire you, or you shall be turned out. Afterwards he learnt who the Dutchesse was.

Thus, SrSir, I have given you an Account, as far as my Memory reaches, of the most material passages ytthat occurred(14)red in my Conversation wthwith SrSir Is:Isaac Newton. There were multitudes of lesser matters, ytthat it is scarce worth while to trouble you with. And whether these may be of any use to the kind Design you mentioned to me, you are the best Iudge of; my Intent & I leave it to you to omit, or insert, & in a word, to make wtwhat use you please of them; my Intent in sending them to you being not only to shew my Veneration of the Memory of SrSir Is.Isaac Newton, but also the Regard I have to your Request, & ytthat I am with great Respect

HondHonoured SrSir

Your humble servtservant

Wm Derham.