<1r>

<2v>

About Midsummer 1664 {sic} he read Oughtred's Clavis wch he understood thou not entirely he having some difficulties about what the author calls scala secundi et tertij gradus relating to the solution of Quadratick cubic Æquations – * < insertion from the right column > * The opinion he had of Oughtred's Clavis appears by the following memorandum found among his papers sig writt in his own writing & signed with his name viz –

Mr Oughtred's Clavis being one of the best as well as one of the first Essays for reviving the Art of Geometrical Resolution & Composition – I agree with the Oxford professors that a correct edition thereof to make it more usefull & bring it into more hands will be both for the honour of our nation & advantage of Mathematicks —

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He then \young & in as he was/ took in hand Des-Cartes's Geometry (that book wch Descartes in his Epistles says is with a sort of defiance says is so difficult to understand) \*/ < insertion from the right column > * he began with the most crabbed studies \& books/ (like a high spirited horse who must be first broke in plowed grounds & the roughest & steepest ways or could otherwise be kept within no bounds < text from f 2v resumes >

When he had got over \read/ two or three pages <3r> & could understand no farther he \being too reserved or modest to trouble any person to instruct him/ began again & went \got over/ two or three or four more till he came to another difficult place, & then began again & advanced farther & continued so doing till he \not only/ made himself master of the whole without having the least light or instruction from any body but discovered the errors \of Descartes/, & \as appears by/ the original book is s wch he read <3v> at that time & is still ex in being & marked in many places with \in/ his own hand \writing/ with these words Error – Error non est Geom. *

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Like a high mettled horse learns to be * < insertion from lower down the right column > * a little before Xmas in the year 1664 he read Shooten's miscellanies & Wallis's works & made large and notes & remarks upon them still extant in being, this was his usual method in all the books he read < text from the right column resumes > he began with the most crabbed studies like a high mettled horse his who must be first galloped \broke/ in plowed grounds & the roughest ways \or otherwise could/ be {sic} kept {sic} him within \no/ bounds – < text from f 3v resumes >

Memm Mr Professor Smith told me he had seen the book it will be proper to mark the passages {sic} & shew they are errours

Soon after he was examined stood to be a Scholar of the House & Dr Barrow examined him in Euclid wch he knew so little of that Dr Barrow conceived a very indifferent opinion of him & for that time postponed his being ha |giving him that preferment till April 1664| <4r> a scholar of the house The Dr never asked him about Descartes's Geometry not imagining that any one could be master of that book without first reading Euclid & Sr Isaac was too modest to mention it himself |so that he was not made Scholar of the House till the year following|

Upon this Sr I. read Euclid over again & began to change his opinion of him when he read that Parallellograms upon the same base & between the same parallells are equal & that other proposition that in a right angled triangle the square of the Hypothonuse is equal to the squares of the two other sides * < insertion from the right column > * & in his latter days he consumed himself spoke with regret of his mistake at the beginning of his Mathematical Studies in applying himself to his Arithmeti at the beginning of his Mathematical Studies to the works of Descartes & other Algebraic writers before he had considered the Elements of Euclid with that attention wch so excellent a writer deserved – Pemberton in the preface < text from f 4r resumes >

<4v>

\About Xmas 1664/ He read next \Shooten's miscellanies &/ Dr Wallis's Arithmetica Infinitorum & on the occasion of a certain interpolation for the quadrature of the circle found that admirable Theorem for raising a binomial to a power given, but before that time a little after reading Des Cartes's Geometry wrote many things concerning the vortices Axes Diameters of curves wch afterwards gaue rise to that excellent tract de Curvis secundi generis \& made several notes & remarks on Shooten's miscellanies wch are still in being, that was his usual method in all the books he read — / ——

Memm. here follows what is writt by Mr Iones, at least must be disposed with it in proper places –

In the winter between the years 1664 & 1665 he found the method of infinite series, & in suer 1665 being forced from Cambridge by the plague computed the area of the Hyperbola at Boothby in Lincolnshire to two & fifty figures by the same method –

Memm – This is writt in a pocket book in Sr I.'s own hand writing

<5r>

In August 1664\4\5// or {sic} 1665 Sr I. bought a prism at Sturbridge fair to try some experiments upon Descartes's book of colours [2] & when he came home & made a \small/ hole in his \window/ shutter & darkened the room & put \placed/ his prism between \at it/ that & the wall he found instead of a circle the light made an {sic} parallellogram |oblong form| with strait sides & \with semi/ circular ends &c wch convinced him Desca of the falsity of Descartes's Hypothesis of Colours <5v> & \he/ then found out his own Theory * thou he could not demonstrate it for want of another prism for wch (with a patience much to be admired in so new & engaging a discovery) he staid till next Sturbridge Fair & then proved what he had before found out — * < insertion from the right column > \X Thus/ Truth as it often happens arose {sic} out of \those/ errors wch gave occasion to the {sic} inquiries by wch themselves were detected.

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In the year 1666 {sic} [3] he retired \again/ from Cambridge on acct of the plague to his mother at Boothby in Lincolnshire {sic} & whilst he was musing in a garden it came <6r> into his thought that the \same/ power of gravity (wch brought \made/ an apple \fall/ from the tree to the ground) was not limited to a certain distance from the earth but that this power must extend much farther than was usually thought – Why not as high as the Moon said he to himself & if so \that must influence/ her motion must be influenced by it \&/ perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that calculation \supposition/ but tak being absent from books & taking the coon estimate in use among Geographers & our sea men before Norwood <6v> had measured the earth, that 60 English miles were contained in one degree of latitude on the surface of the Earth his computation did not agree with his Theory & inclined him then \then/ to think entertain a notion that together with the force \power/ of gravity there might be a mixture of that force wch the moon would have if it was carried along in a vortex, but when the Tract of Picard of the measure \of the/ earth came out shewing that a degree was \about/ 69$\frac{1}{2}$ English miles <7r> He began his calculation a new & found it perfectly agreable to the \his/ Theory –

See Pemberton's account of this particular in his preface who says there that it was a letter from Hook wch put Sr I. upon recalculating & that letter Du Moivre says was not writt till 1673 – the difference may be ascertained by examining when Picard's book came out — * < insertion from the right column > \* Generally/ Often the whole life of those who should push farther & strike out new paths is spent in make new discoveries is spent in learning only what is already found out but Sr Is # < text from f 7r resumes > # Having read only the few books already mentioned some of wch rather led him into errors, & <7v> & without the least help or instruction from any person he laid the foundation of all his discoveries before hee {sic} was 24 years old * |Like \Like This/ Alexander he had| < insertion from the right column > He had run over |  made himself master in Philosophy subdued all Nature at an age when \even/ the Cesars in learning were but just setting out | beginning their conquests – & must call to every one's mind that passage in Iob. 32. c. 7. verse – I said days should speak & multitude of years should teach wisdom, but there is a spirit in man & the inspiration of the Almighty giveth them understanding

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Soon after

When he was in the warmest pursuit of his discoveries he |going out| left a candle on his table amongst his papers & being |meeting somebody who| diverted \him/ from returning \as he intended/ when he went out, the candle sett fire to his papers & upon my asking <8r> him wether they related to his opticks or the method of Fluxions {sic} – he said to both & that he was forced to begin \work them all over/ again – Memm Dr Stukeley says he \had also/ writt {sic} a piece of Chymistry explaining the principles of that mysterious art upon experimental & mathematical proof & valued it much but it was unluckily burnt in his laboratory wch casually took fire, & he would never undertake that work again – Nor is there any \compleat/ treatise on {sic} this subject <8v> amongst his papers thou there are several volumes in his own hand writing wch are cheifly extracts out of Chymical authus {sic} Nor is it to be thought he spent so many hours in that study without producing something \more/ regular \& larger/ treatise upon it, & \than/ the Queries at the end of the Opticks wch are certainly the result of long labour & study & contain a fund of Philosophy wch will employ the learned world for many centuries

[1] * (wch Hobbes say calls the mother of all Philosophy) – Human nature – p. 112 –

[2] Memm Sr I. in the Philosophica {sic} transactions – 1. Vol. {Cowlturp} p. 128 – says it was 1666 – but in the same page he mentions using 2 prisms wch he told me he did not buy the 2d till the year following – NB. he does not name Descartes but calls his book the celebrated Phænomena of colours

[3] Memm. he says so p. 296 Phil. Tran. Abrid. p. 196 –