Catalogue Entry: OTHE00015

Memoirs of the Life, Writings, and Discoveries of Sir Isaac Newton. Vol. 1 (Edinburgh: 1855)

Author: David Brewster

Source: Memoirs of the Life, Writings, and Discoveries of Sir Isaac Newton, vol. 1 (Edinburgh: 1855).

[1] This letter is docqueted by Conduiitt, "Letter sent by me concerning Sir I. N.'s Invention."

[2] I have not succeeded in ascertaining to whom this letter was addressed. It was probably a circular sent to more than one person. I have found a letter from John Craig, and a paper by De Moivre, which have the appearance of being answers to it, but the dates of both are earlier than that of Conduitt's letter. In a letter dated April 16, 1729, Conduitt made a similar application to Professor Machin.

[3] In a letter on the subject of a large "monumental picture to Newton's memory," for Conduitt himself. This letter is docqueted, "Sent to Westgarth," who seems to have been then in Italy.

[4] Life of Bentley, p. 180.

[5] The Marquis La Place. See his Exposition du Système du Monde, Livre 5me, chap. vi. p. 336.

[6]

The issue of this marriage was a son and two daughters, — Benjamin, Mary, and Hannah Smith, from whom were descended the four nephews and nieces who inherited Sir Isaac's personal estate.

The following account from Conduit's MSS. of Mrs. Newton's marriage to Mr. Smith, was given to Mr. Conduit "by Mrs. Hutton, whose maiden name was Ayscough:" —

"Mr. Smith, a neighboring clergyman, who had a very good estate, had lived a bachelor till he was pretty old, and one of his parishioners advising him to marry, he said he did not know where to meet with a good wife. The man answered, the widow Newton is an extraordinary good woman. But, saith Mr. Smith, how do I know she will have me, and I don't care to ask and be denied; but if you will go and ask her, I will pay you for your day's work. He went accordingly. Her answer was, she would be advised by her brother Ayscough. Upon which Mr. Smith sent the same person to Mr. Ayscough on the same errand, who, upon consulting with his sister, treated with Mr. Smith, who gave her son Isaac a parcel of land, being one of the terms insisted upon by the widow if she married him." This parcel of land was given by Mrs. Smith, and was probably her property of Sewstern. — See the Annual Register 1776, Characters, p. 25.

[7] It is a curious fact that Leibnitz, the rival of Newton, had laboured at similar inventions. In a letter written to Sir Isaac from Hanover, about a month after Leibnitz's death, on the 14th November 1716, the writer informs him that Leibnitz had laboured all his life to invent machines, which had never succeeded, and that he was particularly desirous of constructing a wind-mill for mines, and a carriage to be moved without horses. Fontenelle, in his Eloge on Leibnitz, mentions these two inventions in different terms. He had bestowed, says he, much time and labour upon his wind-mill for draining the water from the deepest mines, but was thwarted in its execution by certain workmen who had opposite interests. In the matter of carriages, his object was merely to render them lighter and more commodious; but a doctor, who believed that Leibnitz had prevented him from getting a pension from the King of Hanover, stated in some printed work, that he had contemplated the invention of a carriage which would perform the journey from Hanover to Amsterdam in twenty four hours. — Mém. Acad. Par. 1718. Hist. p. 115.

[8] One of these dials was taken down in 1844, along with the stone on which it was cut, by Mr. Turnor of Stoke Rochford, and presented by his uncle, the Rev. <12note> Charles Turnor, to the Museum of the Royal Society. The dial was traced on a large stone in the south wall, at the angle of the building, and about six feet from the ground. The name NEWTON, with the exception of the first two letters, which have been obliterated, may be seen under the dial in rude and capital letters. The other dial is smaller than this, but not in good preservation. The gnomons of these dials have unfortunately disappeared. In the woodcut representing the Manor-house of Woolsthorpe, the birth-place of Sir Isaac, are shown the places on the wall where the dials were traced. — See Phil. Trans. 1845, pp. 141, 142.

[9] Mrs. Hutton mentioned to Mr. Conduitt that this was the profession to which Newton was to be brought up.

[10] MSS. of Conduit among the family papers.

[11]

Mr. Conduit, in his MSS. notes, mentions two of these memorandum books in the following manner: — "I find in a paper book of his to which he has put his name, and 1659, — Rules for drawing and making colours;" and in another of the same year, "Prosodia written out." The first of these books I did not find among the family papers; but the second is the one referred to in the text. The following is its title: —

Quisquis in hunc librum

Teneros conjecit ocellos,

Nomen subscriptum perle-

gat ipse meum.

Isaac Newton,

Martii 19, 1659.

On the second page is the title Utilissimum Prosodiæ Supplementum, which terminates on the 33d page with the date March 26, and is followed by an Appendix of three pages.

At the end of the book there is a list of his expenses, entitled Impensa propria, occupying fourteen pages. On the 4th page the expenses are summed up thus

Totum,£356 Habui,400 ——— Habeo.0146

On the 5th page there are fourteen loans of money, extended thus:

Lent Agatha,£0111 Lent Gooch,100

and he then adds at the bottom of the page, lent out 13 shillings more than £4.

<18note> Among the entries areChessemen and dial,£014 Effigies amoris,010 Do.0010

and on the last page are entered seven loans, amounting to £3, 2s. 6d. There is likewise an entry of "Income from a glasse and other things to my chamber-fellow, £0 0 9." Another page is entitled

OTIOSE ET FRUSTRA EXPENSA. Supersedeas.Sherbet and reaskes. China ale.Beere. Cherries.Cake. Tart.Bread. Bottled beere.Milk. Marmelot.Butter. Custards.Cheese.

[12] MSS. of Conduit among the family papers.

[13]

"This class of students," says Mr. Edleston, "were required to perform various menial services, which now seem to be considered degrading to a young man who is endeavouring, by the force of his intellect, to raise himself to his proper position in society. The following extract from the Conclusion Book of Trinity College, <21> while it affords an example of one of their duties, will also serve to illustrate the rampant buoyancy of the academic youth at the time of the Restoration."

"Jan. 16, 1660-1. Ordered also that no Bachelor, of what condition soever, nor any Undergraduate, come into the upper butteries, save only a Sizar that is sent to see his tutor's quantum, and then to stay no longer than is requisite for that purpose, under penalty of 6d. for every time; but if any shall leap over the hatch, or strike a butler or his servant upon this account of being hindered to come into the butteries, he shall undergo the censure of the Masters and Seniors.' — Edleston's Correspondence of Sir Isaac Newton and Professor Cotes, Lond. 1850, p. xli.

[14] Collections for the History of the Town and Soke of Grantham, &c. By Edmund Turnor, F.R.S., F.S.A. Lond. 1806, pp. 159,160. Conduit's MSS. were written subsequently to the Memoirs above referred to.

[15] Demoivre says, that the Book on Astrology was bought at Stourbridge, the seat of the Cambridge fair, close to the town.

[16] Newton's copy of Descartes' Geometry I have seen among the family papers. It is marked in many places with his own hand, Error, Error, non est Geom.

[17] This statement is different from that of Conduit in his Memoirs, but I give it on his own authority, as founded on later inquiries.

[18] Pemberton's, View of Sir Isaac Newton's Philosophy. PREF.

[19] In this commonplace book we find the date November 1665, so that its contents were written in 1664 and 1665.

[20] In the commonplace book which contains the "annotations out of Schooten and Wallis," no expenses are entered, so that there must be another note-book which I have not found, in which the purchase of Schooten's Miscellanies and Descartes' Geometry is recorded. It is not likely that the second note-book of 1659, mentioned by Conduit, contained expenses incurred in 1663 and 1664.

[21] Conduit remarks that in reading this work he did not entirely understand it, especially what "relates to Quadratic and Cubic Equation" — MSS. A translation of the Clavis was published and recommended by Halley in 1694.

[22] The plague commenced in Westminster about the end of 1664. It raged during the hotter months of 1665, and had so far abated before the end of the year, that the inhabitants returned to their homes in December. The date of Newton's quitting Cambridge, viz., 1665, as written under his own hand in his commonplace book, coincides with these facts, and is on this account probably the correct one; but Pemberton makes the date 1666, which is adopted by Professor Rigaud, and seems to <24> be given by Newton himself in the Phil. Trans., vol. vi. p. 3080. Rigaud's Hist. Essay on the first publication of Sir Isaac Newton's Principia, p. 1, note.

[23] A village in Lincolnshire, near Sleaford, where Newton was probably on a visit.

[24] This comet passed its perihelion on the 4th December at midnight.

[25] Book II, Part IV, Obs. 13.

[26] Conduit's MSS.

[27] Edleston's Correspondence, &c. &c., App. xxi, xlv.

[28] Rigaud's Hist. Essay, &c., App. No. II. p. 20. From the Macclesfield MSS. Raphson Historia Fluxionum, Cap. 1. p. 1, Cap. xiii. p. 92, and English Edition, pp. 115, 116.

[29] These papers in the Macclesfield Collection are quoted by Newton himself in his Observations on Leibnitz's celebrated Letter to the Abbé Conti, dated 9th April 1716. See Raphson's Hist. of Fluxions, pp. 103 and 116.

[30] Neither Pemberton nor Whiston, who received from Newton himself the History of his first Ideas of Gravity, records the story of the falling apple. It was mentioned, however, to Voltaire by Catherine Barton, Newton's niece, and to Mr. Green by Martin Folkes, the President of the Royal Society. We saw the apple tree in 1814, and brought away a portion of one of its roots. The tree was so much decayed that it was taken down in 1820, and the wood of it carefully preserved by Mr. Turnor of Stoke Rocheford. See Voltaire's Philosophie de Newton, 3me part. Chap. III. Green's Philosophy of Expansive and Contractive Forces, p. 972, and Rigaud's Hist. Essay, p. 2.

[31] Phil. Trans. vol. vi. p. 3075.

[32] "Verum quod tenellæ matres factitant, a me depulsum partum amicorum haud recusantium nutriciæ curæ commisi, pront ipsis visum esset, educandum aut exponendum, quorum unus (ipsos enim honestum duco nominatim agnoscere) D. Isaacus Newtonus, collega noster (peregregiæ vir indolis ac insignis peritiæ) exemplar revisit, aliqua corrigenda monens, sed et de suo nonulla penu suggerens quæ nostris alicubi cum laude innexa cernes." The other friend was John Collins, whom he calls the Mersennus of our nation. Epist. ad Lectorem. The imprimatur of this volume is dated March 1668-9.

[33] The addition by Newton is a singularly elegant and expeditious method at the end of Lect. xiv., of determining geometrically in every case, the image formed by lenses, and describing the lens which projects the image on a given point.

[34] Barrow introduces the subject of colours by the following remarkable sentence: "Quoniam colorum incidit mentio, quid si de illis (etsi præter morem et ordinem) paucula divinavero?" — Lect. xii. ad finem.

[35]

The only information which we have relative to the times of Newton's leaving and returning to Cambridge, in consequence of the Plague, is contained in the following note by Mr. Edleston: —

"The College was 'dismissed' June 22d, on the reappearance of the Plague. The Fellows and Scholars were allowed their commons during their absence. Newton received on this account

3s. 4d. weekly, for 13 weeks, ending Michaelmas 1666. " " "12 "Dec. 21. " " "5 "Ladyday 1667."

The College had been also dismissed the previous year, August 8th, on the breaking out of the plague, but Newton must have left Cambridge before that, as his name does not appear in the list of those who received extra commons for 612 weeks on the occasion. "Aug. 7, 1665. — A month's commons (beginning Aug. 8th) allowed to all Fellows and Scholars which now go into the country upon occasion of the pestilence." — ( Conclusion Book.)

"On the continuance of the scourge, we find him with others receiving the allowance for commons for 12 weeks, in the quarter ending Dec. 21, 1665, and for 13 weeks ending Ladyday 1666." — Edleston's Correspondence, &c., p. xlii. note 8.

[36] Thomas Burnet, author of the Theoria Telluris Sacra, and a future friend and correspondent of Sir Isaac.

[37] This note-book, of which three-fourths is white paper, begins at one end with three pages of short-hand, which is followed by his expenses. At the other end of the book there is a Nova Cubi . . . . Tabella, and a number of problems in geometry and the Conic Sections.

[38] Flowers of Putty, an oxide of zinc used in polishing lenses and metallic specula.

[39]

As this list of expenses is very interesting, and as the book which contains them has obviously been preserved by Newton himself as evidence of the priority of some of his researches, the following abstract of it is presented to the reader: —

1665.

Received, May 23d, whereof I gave my tutor 5s., £5 0 0Remaining in my hands since last quarter, 3 8 4In all, £8 8 4

This account of expenses extends only to six and a half pages, and records many loans. The following are among the entries: —

Drills, gravers, a hone, a hammer, and a mandril, £0 5 0 A magnet, 0 16 0 Compasses, 0 3 6 Glass bubbles, 0 4 0 My Bachelor's account, 0 17 6 At the tavern several other times, 1 0 0 Spent on my cousin Ayscough, 0 12 6 On other acquaintance, 0 10 0 Cloth, 2 yards, and buckles for a vest, 2 0 0 Philosophical Intelligences, 0 9 6 The Hist. of the Royal Society, 0 7 0 Gunter's Book and Sector to Dr. Fox, 0 5 0 Lost at cards twice, 0 15 0 At the tavern twice, 0 3 6 I went into the country, Dec. 4, 1667. I returned to Cambridge, Feb. 12, 1667. Received of my mother, 30 0 0 My journey, 0 7 6 For my degree to the College, 5 10 0 To the proctor, 2 0 0 To three prisms, 3 0 0 Four ounces of putty, 0 1 4 Lent to Dr. Wickins, 1 7 6 Bacon's Miscellanies, 0 1 6 Expenses caused by my degree, 0 15 0 A Bible binding, 0 3 0 <33> For oranges for my sister, £0 4 2 Spent on my journey to London, and 4s. or 5s. more which my mother gave me in the country, 5 10 0 I went to London, Wednesday, August 5th, and returned to Cambridge on Monday, September 28, 1668. Lent Dr. Wickins, 0 11 0

April 1669.

For glasses in Cambridge. For glasses in London. For aquafortis, sublimate, oyle pink, fine silver, antimony, vinegar, spirit of wine, white lead, salt of tartar, 2 0 0 A furnace,0 8 0 Air furnace, 0 7 0 Theatrum chemicum, 1 8 0 Lent Wardwell 3s., and his wife 2s., 0 5 0

[40] See Letter to Oldenburgh, Feb. 1671-2, in Newtoni Opera, by Horsley, tom. iv. p. 295; and Letter to a Friend, Feb. 23, 1668-9, in Gregory's Catoptrics, edit. 3d, p. 259; or in the Macclesfield Collections, vol. ii. p. 289.

[41] See Appendix, No. I.

[42] Dioptrice, cap. viii. ix., 1629.

[43] Optica Promota: Definitiones, 3. Lond. 1663.

[44]

Isaaci Vossii De Lucis Natura et Proprietate, Amstel. 1662. As the opinions of Vossius have not been referred to by any of our historians of science, the following passages may be interesting.

"Primus itaque color, si tamen color dicendus sit, is est albus, pelluciditatem proxime hic accedit. Insunt itaque et lumini omnes colores, licet non semper visibiliter; nempe ut flamma intensa alba et unicolor apparet, eadem si per nebula aut aliud densius corpus spectetur, varios induit colores. Pari quoque ratione, Lux, licet invisibilis ant alba ut sic dicam, si per prisma vitreum, aut aerem roridum transeat, similiter varios colores induit." — P. 6.

"Omnem tamen lucem secum colores deferre et eo colligi potest quod si per lentem vitream, aut etiam per foramen, lumen in obscurum admittatur cubiculum in muro aut linteo remotiore manifeste omnes videantur colores, cum tamen in punctis decussationis radiorum et locis minimum lenti vicinis, nullus color sed purum tantum compareat lumen." — P. 64.

"Quapropter non recte ii sentiunt qui colorem vocant Lumen modificatum." — P. 59.

[45] Phil. Trans., vol. vii., No. 80. Feb. 19, 1672

[46] Phil. Trans., vol. vii., No. 81, p. 4004. March 25, 1672.

[47] See Journal des Savans , 1672, pp. 80 and 121; and Phil. Trans., No. 83, p. 4056, May 20, 1672.

[48] Gregory's Catoptrics, App. 261. In this controversy, Newton never claimed any credit for the invention of a new form of the reflecting telescope, and was certainly surprised at the notice it excited among persons that either were, or ought to have been, acquainted with the previous invention of Gregory. In his letter to Mr. Collins, he speaks in the kindest manner of Gregory. "I doubt not that when Mr. Gregory wrote his Optica Promota, he could have described more fashions than one of these telescopes, and perhaps have run through all the possible cases of them, if he had thought it worth his pains. Because Mr. Cassegrain propounded his supposed invention pompously, as if the main business was the contrivance of these instruments, I thought fit to signify that that was none of his contrivance, nor so advantageous as he imagined. And I have now sent you these farther considerations on Mr. Gregory's answer, only to let you see that I chose the most easy and practicable way to make the first trials. Others may try other ways, nor do I think it material which way these instruments are perfected, so they be perfected. — Dec. 10, 1672." See the Macclesfield Collections, vol. ii. pp. 346, 347, or Newtoni Opera by Horsley, vol. iv. p. 288.

[49] July 13, 1672, in the Macclesfield Collections, vol. ii. p. 333.

[50] Sir Isaac seems to have been the first person who suggested the idea that vision might be rendered indistinct by the collision of the rays when they cross one another at the focus of mirrors or lenses. In speaking of the use of more than one <51> eye-glass in the Gregorian telescope, he states, that "by the iterated decussations of the rays, objects will be rendered less distinct , as is manifest in dioptric telescopes, where two or three eye-glasses are applied to erect the object." — Letter to Collins, Dec. 10, 1672; Macclesfield Collections, vol. ii. p. 344. In the course or some experiments on this subject, I found that the sections of the cone of rays, are never so distinct and well-defined after the rays have crossed as before. — (Treatise on New Phil. Inst., pp. 44 & 193). And Captain Kater, in comparing two equal telescopes, the one Gregorian and the other Cassegrainian, found that the intensity of the light within the focus was nearly double of what it was without the focus. In other experiments, he found the ratio as 1000 to 788 — Phil. Trans., pp. 13, 14. Mr. Tulley, however, in making similar experiments, did not confirm the results obtained by Captain Kater. I have found, in confirmation of these facts, that the negative diffractive fringes produced by rays which do not cross one another before they enter the eye, are more distinct than the positive ones which do cross. — Treatise on Optics, Edit. of 1853, p. 117.

[51] Dr. Hook made several experiments with the speculum executed by Mr. Reeves, and did not find it so bad as Gregory thought. See Newton's letter above referred to.

[52] Letter from Gregory to Collins and Newton, Sept. 26. 1672.

[53] Biog. Brit., Art. Newton, p. 3217.

[54] Smith's Optics, vol. ii. Remarks, p. 80.

[55] Caleb Smith proposed to correct the colour produced by the two refractions, by a concave lens placed between the speculum and the small receiver, or by making the surface of a rectangular glass prism concave. — Phil. Trans. 1739, p. 326.

[56] See Prof. Rigaud's Biographical Account of John Hadley, Esq., pp. 7-11.

[57] Phil. Trans., vol. xxxii. No. 376, March and April, 1723, p. 303.

[58] Phil. Trans., July and August 1723, p. 382.

[59] Gregory's Catoptrics, pp. 250, 285.

[60] Ibid., p. 385

[61] The Hon. Samuel Molyneux and Hadley in Smith's Optics, vol. ii. p. 302, § 782.

[62] Ibid., p. 363, § 913.

[63] This telescope, according to Dr. Smith, was so excellent that it was scarcely inferior to Hadley's of 5 feet 212 inches in length. It bore a power of 226, as determined by Mr. Hawksbee, Mr. Folkes, and Dr. Jurin. See Smith's Optics; Remarks, p. 79.

[64] This process, drawn up partly by Molyneux, and partly by Hadley, is printed in Dr. Smith's Optics, vol. ii. p. 301.

[65] Maclaurin in Smith's Optics, vol. ii., Remarks, p. 81.

[66] This telescope was removed from the Observatory upon the establishment of the Astronomical Institution, and is, we believe, now lying dismantled in some garret of the city.

[67] For an account of the Decline of Science in England, here alluded to, we refer the reader to Sir John Herschel's Treatise on Sound, to Mr. Airy's Report on Astronomy, in the Report of the British Association for 1833, and to Mr. Babbage's interesting volume, On the Decline of Science. See also Quarterly Review, October 1830, and North British Review, vol. xiv. p. 235.

[68] See Transactions of the Astronomical Society, vol. ii. p. 413.

[69] A fine reflecting telescope, with a speculum two feet in diameter, and a focal length of twenty feet, has been recently constructed by Mr. Lassels, who has made with it several important discoveries within the limits of our own system.

[70] A box containing a second speculum is shewn at Y.

[71] This disc of flint-glass was executed by Messrs. Chance, Brothers, and Company, of the Smethwick Glass-works, and was rewarded with a council medal of the Great Exhibition. — See Reports of the Juries, p. 529.

[72] This proposal, which was first made by the author in September 1844, is likely to be now carried into effect. A committee of the British Association, and of the Royal Society, have, after a careful consideration of the subject, applied to Government for the necessary funds.

[73] Letters to Collins from 1669 to September 27, 1670. — Macclesfield Correspondence , Vol. ii.

[74] This work was never finished. It was published by Horsley, under the title of Geometria Analytica, from three different MSS. — See Newtoni Opera, tom. i. pp. 391-518. A translation of it had been published by Colson in 1736.

[75] The communication is dated 13th April 1672, and is published in the Transactions, No. 82, p. 4059, April 22, 1672.

[76] Phil. Trans., No. 84, p. 4091, June 17, 1672.

[77] Phil. Trans., No. 85, p. 5012, July 15, 1672.

[78] Ibid., p. 5014.

[79] Ibid., p. 5018.

[80] Phil. Trans., No. 84, p. 4080, June 17, 1672. This paper is part of a letter to Oldenburg, dated July 6, 1672, from Stoake Park, Northamptonshire.

[81] Phil. Trans., No. 110, p. 217.

[82] Phil. Trans., No. 121, p. 503.

[83] Phil. Trans., No. 121, p. 503

[84] Ibid., No. 123, p. 556.

[85] A short time before the commencement of this controversy, Linus communicated to the Royal Society a paper entitled Optical Assertions concerning the Rainbow, which appeared in their Transactions, No. 117, p. 386. How such a paper could have been published by so learned a body seems very incomprehensible. Linus was celebrated as a dial-maker. Mr. Charles Ellis mentions one of his dials at Liege, in which the hours were distinguished by touch, and says that they were "the originals of those formerly in our Privy Gardens." — Phil. Trans., No. 283, 1703, vol. xv. p. 1418.

[86] This view of Descartes' theory and of Hooke's opinions, is given by Newton in his letter to Oldenburg, dated 21st December 1675. General Dict. vol. vii. p. 783, or Macclesfield Correspondence, vol. ii. p. 378.

[87] Newtoni Opera, tom. iv. pp. 322-342.

[88] Phil. Trans., vol. viii. No. 96, p. 6086, July 1693.

[89] Phil. Trans., No. 97, p. 6108.

[90] Letter to Oldenburg without a date, but probably in April 1673.

[91] It is curious to observe how little accurate knowledge of the great optical discoveries of the age was possessed by Leibnitz. In a letter addressed to Huygens, dated 8th September 1679, he says, — "I hear from Mr. de Mariotte that you are about to give us your Dioptrics, so long wished for. I have a great desire to know beforehand if you are satisfied with the ratio of refraction proposed by Descartes. I confess that I am neither wholly satisfied with it, nor with the explanation of Mr. Fermat, given in the third volume (Lett. 51) of Descartes' Letters." — Ch. Hugenii, Exercit. Math., tom. i. pp. 7, 8; lett. iv., Hag. Com. 1833. Huygens made no reply to this question, though he answered Leibnitz's letter on the 22d November. In replying to this letter, Leibnitz repeats the same question, confessing that he was neither satisfied with the ratio of Descartes, nor that of Fermat deduced from an opposite supposition. To this question he adds, — "I wish to know also if you believe that the irregularity of refraction, — for example, that which Mr. Newton has remarked, — ought to hurt telescopes considerably?" — Ibid., lett. vi. p. 17. An answer to this question was given by Huygens in a subsequent letter, for we find Leibnitz, in a letter dated 26th June 1680, expressing his satisfaction that Huygens had formed the same opinion of the "pretended demonstration of the laws of refraction given by Descartes." — Ibid., lett. viii. p. 20. No reply is made to the question about Newton's doctrine of the cause of the imperfection of refracting telescopes; but ten years afterwards, when Leibnitz had received from Huygens a copy of his Traité de la Lumière, we find the following curious passage in his letter to Leibnitz, dated 24th August 1690: — "I have said nothing respecting colours in my Traité de la Lumière, finding this subject very difficult, and particularly from the great number of different ways in which colours are produced. Mr. Newton promised something on the subject, and communicated to me some very fine experiments which he had collected. It seems that you have also thought on the subject, and apparently to some purpose." — Ibid., lett. xi. pp. 27, 28.

[92] This letter is dated November 18, 1676, and was written after receiving an account of the experiments of Lucas. — Macclesfield Correspondence , vol. ii. p. 405.

[93] Gentleman's Magazine, 1799, Supplement, pp. 1186 and 999.

[94] Correspondence, &c., pp. xlviii. xlix. note, 38.

[95] This appears from a memorandum on the back of Newton's letter to him.

[96] The admission-money to the Royal Society was £2, and the payments one shilling a week.

[97] In reference to an application from Francis Aston for a dispensation similar to that received by Newton, Dr. Barrow, then Master of Trinity, in declining to grant it, says, — "Indeed a Fellowship with us is now so poor, that I cannot think it worth holding by an ingenuous person upon terms liable to so much scruple." — Edleston's Correspondence, p. 1.

[98] In a volume of MSS. in the British Museum relating to the Royal Society, there is, as Mr. Weld informs us, a sheet containing the names of Fellows who will probably pay, and give yearly one entertainment to the society. Opposite the names of Dr. Grew, Hooke, and Newton, are the words, "No pay, but will contribute experiments." The date of this list, if it has any, is not mentioned. See Baily's Life of Flamsteed, p. 90, note, and Weld's Hist. of the Royal Society, vol. i. p. 250, note.

[99] We found two copies of this scheme, one of which is more complete than the other. The first paragraph of the copy given in the text is wanting in the less perfect copy, but in other respects they are nearly the same. There is no date upon either of the copies.

[100] Written by mistake Meteorology; but in the other copy it is Mineralogy.

[101] See especially the Quarterly Review, October 1830, vol. xliii. pp. 305-342; Edinburgh Review, January 1835, vol. lx. p. 363; Edinburgh Journal of Science, passim; North British Review, vol. iv. pp. 410-412; vol. vi. p. 506; vol. xiv. pp. 281-288; from the last of which articles some of the paragraphs in the text are transferred.

[102] Corresponding to the Académiciens Libres of the Academy of Sciences in Paris.

[103] Optics, Prop. vii., Book ii., p. 91. In his reply to Hooke, who justly "reprehended him for laying aside the thoughts of improving optics by refractions," he seems to modify his opinion by saying that he tried what might be done "by two or more glasses or crystals, with water or some other fluid between them." "But what the results by theory or by trials have been, he might possibly find a more proper occasion to declare." This was written in 1672, and we can therefore say with certainty that he failed in this attempt, as it was in 1684 that he pronounced the case to be desperate. It is a curious circumstance that David Gregory, in his Lectures delivered in Edinburgh in 1684, suggests that, in imitation of the human eye, the {object-glasses} of telescopes might be composed of media of different density. In Brown's translation of Gregory, the sense of the passage is not brought out. See Gregory's Catoptries, Prop. xxiv., Schol., pp. 110, 111.

[104] See Tilloch's Philosophical Magazine, Nov. 1798, vol. ii. p. 177{,}

[105] See my Treatise on Optics, new edit., p. 506.

[106] Optics, Part, ii., Prop. iii., p. 110.

[107] Edinburgh Transactions, 1831, xii. p. 124.

[108] Phil. Mag. vol. xxx. p. 73.

[109] Bibl. Univers. Août 1847.

[110] Silliman'sJournal, vol. iv. p. 388. 1847.

[111] Hist. of Inductive Sciences, vol. ii. p. 361; and Edinburgh Review, vol. lxvi. p. 136, and vol. lxxiv. p. 288.

[112] Répetoire d'Optique, tom. ii. p. 459.

[113] Poggendorff's Annalen. 1852, No. 8.

[114] Ann. de Chim. et de Phys. tom xxxv. p. 385 &c.

[115] The changes of colour in the spectrum at different seasons of the year, and the different hours of the day, and when formed from different portions of the illuminated sky, as well as from the direct light of the sun, are very remarkable. We have mentioned one or two of them in the Edinburgh Review, vol. lxxiv. p. 284, Jan. 1842. One of these observations is as follows: — "October 23, 1832. 11th, The yellow comes distinctly up to F, and a little beyond it; i.e., the blue has been all absorbed in the green space of Fraunhofer's spectrum from E to F." In another observation on the 5th February 1833, the green space was wholly yellow.

[116] Letter to Oldenburg, Feb. 6, 1672, in Phil. Trans. No. 80, p. 3081, § 3.

[117] Phil. Trans. 1852.

[118] See my Treatise on Optics, new edition, pp. 182, 183.

[119] October 19, 1675. Macclesfield Correspondence, vol. ii. P. 280.

[120] "Harum . . . librationum causas Hypothesi elegantissima explicavit nobis vir cl. Isaac Newton, cujus humanitati hoc et aliis nominibus plurimum debere me lubens profiteor." — Mercator's Institutiones Astronomicæ; , p. 286.

[121] Newton's letter had been forwarded to Mr. Lucas, and therefore the sentence does not appear in it. — See Phil. Trans., No. 128, p. 703.

[122] Eddleston's Correspondence, App. No. xvi. p. 260.

[123] He wrote a work entitled, Herefordshire Orchards a Pattern for England, 1656. See Birch's Hist. of the Royal Society, vol. iv. p. 235.

[124] See Appendix, No. II.

[125] Dr. Whewell states that Descartes regarded light as "consisting of small particles emitted by the luminous body," but Mr. Vernon Harcourt (Letter to Lord Brougham, p. 32) has shewn the incorrectness of this opinion. See Œuvres de Descartes, tom. vii. pp. 193, 240.

[126] Newtoni Opera, tom. iv. pp. 325, 326.

[127] Phil. Trans., 1672, No. 88, p. 5088.

[128] Newtoni Opera, tom. iv. pp. 378-381; or Birch, vol. iii. p. 278.

[129] In a paper entitled "Observations," which accompanied this letter, but which was not printed, Newton says that Hooke, in his Micrographia, had "delivered many very excellent things concerning the colours of thin plates, and other natural bodies, which he had not scrupled to make use of as far as they were for his purpose."

[130] In his Optics, published many years after this, in 1704, Newton does not give Hooke the credit of having made these observations.

[131] Letter to Boyle, Newtoni Opera, tom. iv. pp. 385-395.

[132] Phil. Trans., 1801; or Lectures on Natural Philosophy, vol. ii. p. 614.

[133] Ibid., vol. i. p. 477.

[134] Optics, edit. 3d, 1720, pp. 336, 339.

[135] Fatio D'huillier, the particular friend of Newton.

[136] Huygenii Exercitationes Mathematicæ, &c., Fascic. i. p. 173.

[137] Experiments and Observations touching Colours. Exp. xix. p. 243, London, 1664.

[138] " Micrographia, or some Physiological Descriptions of Minute Bodies made by magnifying-glasses, with Observations and Inquiries thereupon." In many of the copies the date is 1667, but the title-page which bears this date was a trick of the printer, to indicate a second edition, which was never printed. The imprimatur of the President of the Royal Society is Nov. 23, 1664. See Ward's Life of Hooke, in the Lives of the Gresham Professors, p. 190.

[139] The reader will observe that the orders here given, and their colours, differ somewhat from those published nearly thirty years afterwards in his " Optics."

[140] Optics, Book ii. Part i., Obs. 7, 18.

[141] Comptes Rendus, &c. &c., tom. xxv. p. 498. 1850.

[142] Treatise on Light, Art. 670.

[143] It is curious that Newton here makes no mention of an ethereal medium as that in which the vibrations are executed, as he does in his Hypothesis, formerly described. See p. 136.

[144] " On the Connexion between the Phenomena of the Absorption of Light and the Colours of Thin Plates." — Phil. Trans. 1837, p. 245.

[145] Edinburgh Journal of Science, vol. i. p. 108. June 1824.

[146] These observations, thirteen in number, entitled " Observations concerning the Reflections and Colours of thick transparent polished Plates, form the fourth part of the Second Book of Optics.

[147] Mém. Acad. par. 1705.

[148] Phil. Trans. 1807.

[149] Edinburgh Transactions, 1815, vol. vii. p. 435.

[150] Art. Chromatics in Encyclopædia Brittanica.

[151] Treatise on Light, § 688-695.

[152] Edinburgh Transactions, 1832, vol. xii.

[153] Optics, Book i., Part ii., Prop. 10.

[154] Optics, Book ii., Part iii.

[155] A full account of these experiments, with coloured drawings of the spectra, will be found in the Edinburgh Transactions, 1833, vol. xii. pp. 538-545.

[156] See Phil. Trans. 1814, p. 397, and 1836, pp. 55, 56.

[157] See Layard's Discoveries in the Ruins of Nineveh, 1853, pp. 674-676; and Phil. Trans. 1837, p. 249.

[158] See Edinburgh Transactions, 1829, vol. xi. p. 322; and Reports of the British Association, 1844, p. 9.

[159] See Phil. Trans. 1814, p. 397; and 1829, p. 301.

[160] See Edinburgh Transactions, 1833, vol. xii. p. 512; and 1846, vol. xvi. p. 111; Reports of the British Association, 1838, pp. 10-12; Phil. Trans. 1845, p. 143; and 1852, p. 463.

[161] In his Memoir on Diffraction, Fresnel has thrown out the idea that, at great incidences, and with very thin laiminæ, the law of refraction may not follow the proportionality of the sines.

[162] See Edinburgh Transactions, vol. xvi. p. 112.

[163] See Birch's Hist. Royal Society, vol. iii. pp. 63, 194, and Hooke's Posthumous works, pp. 186-190.

[164] Physico-Mathesis de Lumine, Coloribus, et Iride, aliisque annexis. Bononiæ, 1665. 4to.

[165] A concave lens is preferable to a convex one, for reasons which will presently be seen; and we recommend that it should be achromatic.

[166] This result had been previously obtained by Sir Isaac Newton.

[167] The hyperbolic form of the fringes had been previously discovered by Dr. Young. — Lect., vol. i. p. 287.

[168] See the Phil. Trans., 1829, pp. 301-317.

[169] These effects are so beautiful, that we have recommended the use of a diffracting apparatus for suggesting patterns for ribands. — See Reports of British Association, 1838, vol. vii. p. 12; Treatise on Optics, Edit. 1853, p. 117.

[170] See Reports of British Association, vol. vii. p. 12, 1838.

[171] Phil. Trans. 1796, p. 227; and 1797, p. 352.

[172] Lord Brougham uses the term polarisation "merely because the effect of the first edge resembles polarisation, and without giving any opinion as to its identity."

[173] Phil. Trans., 1850, pp. 235-260.

[174] Part iii., Prop. viii. ix., &c.

[175] Probably Sulphate of Barytes.

[176] Optics, Book ii., Part iii., Prop. x.

[177] See Transactions of the Geological Society, 2d Series, vol. iii. p. 455; and North British Review, vol. xviii. p. 227.

[178] Journal Book of the Royal Society.

[179] It was published in the Phil. Trans. 1671, p. 2039.

[180] Traité de Lumière, chap. v. p. 57 ; and Maseres' Scriptores Opticæ, p. 234.

[181] Query 25th and 26th at the end of the work.

[182] The term unusual, and the ratio of the sines, viz. 5 to 3, were given by Bartholinus in the abstract of his Paper in the Phil. Trans., No. 67, Jan. 1670-1, pp. 20, 39.

[183] Traité de Mineralogie, tom. i. p. 159, Note.

[184] Hauy's Elements of Nat. Phil., by Gregory, vol. ii p. 337.

[185] See Appendix, No. III.

[186] Correspondence, &c. pp. 264-273. From the originals in the British Museum, Add. MSS., 4237, fol. 32 and 34.

[187] Hooke's Collections, March 1682, No. 6, p. 167.

[188] The Thalami Nervorum Opticorum.

[189] Briggs considers this muscle necessary to prevent squinting, by "keeping the eye even and in sight." — Hooke's Coll., March 1682, p. 170.

[190] Dated Trin. Coll. Cambridge, September 12, 1682. Appendix, No. IV.

[191] Descartes himself distinctly states that we see objects single with two eyes in exactly the same way as we feel objects single with two hands, forgetting that we see them double by the displacement of the coincident images, and never feel them double by the two hands. See Descartes' Dioptrice, cap. 6, De Visione, Art. X. The experiment of feeling a pea double between two fingers, is not hostile to this observation.

[192] This is precisely the theory of Rohault, see p. 229.

[193] This letter contains, as will be seen in the Appendix, No. IV., a paragraph respecting the opinions of a Mr. Sheldrake, who, as Mr. Edleston informs us, was a Fellow of Corpus Christi College, and seven years senior to Newton. Mr. Sheldrake <224> states that vision is more distinct when the eye is directed to the object, than when the object is above or below the optic axes. I do not recollect that this curious fact has been stated by any previous writer on vision.

[194] See Appendix, No. V.

[195] Dated Cambridge, May 1685.

[196] The one the Theory of Vision, and the other his Ophthalmographia. Cantab. 1676, and Lond. 1687.

[197] See Appendix, No. VI.

[198] See Appendix, NO. VII.

[199] Although it is evident, from a careful perusal of the 15th Query, that it contains the same doctrine of the semi-decussation of the optic nerves which is given in the MS., yet it has been misunderstood by Dr. Reid, who obviously had not seen the copy of it in Harris's Optics. "Sir Isaac Newton," says Dr. Reid, (Inquiry, cap. vi. sect. 13), "who was too judicious a philosopher and too accurate an observer to have offered even a conjecture which did not tally with the facts which had fallen under his observation, proposes a query with respect to the cause of it, (namely, the relation and sympathy between corresponding points of the two retinæ.)" — Optics, Query 15. Dr. Reid seems not to have detected the doctrine of semi-decussation in the Query, and to have believed that individual nerves, not half-nerves, from the two sides of both eyes, united before they reached the brain, and there produced a joint and single impression; and Dr. Alison has either taken up Dr. Reid's opinion, or misunderstood the Query, and also the theory of semi-decussation. "It is well-known," he says, "that an explanation (of single vision by means of double images) was proposed by Newton, fully considered by Reid, and since supported by Wollaston, (often called the theory of Wollaston, but quite incorrectly,) proceeding on the supposition of a semi-decussation of the human optic nerves at their commissure, whereby the fibres from the right half of the retina go to the right optic lobe in the brain, and vice versa." This is the theory of Rohault, and not of Newton and Wollaston, in which the half-fibres, from the right half of the retina of each eye, unite into one fibre at their commissure GH in Fig. 12, and then go to the right optic lobe.

[200] Sir Isaac draws other four conclusions from his theory, but they will find a fitter place in the Appendix, No. VIII.

[201] A Latin translation of Rohault's work was published in 1708, by Dr. Clarke, "with annotations chiefly from the philosophy of Newton, and yet no notice is taken of Newton's Theory, as contained in his l5th Query, although Dr. Clarke had translated the Optics into Latin. He adds a note stating, that the conjecture <230> respecting the fibres of the optic nerve had not yet been confirmed by dissection. Part I. cap. 31, p. 225, note.

[202] The suffusio dimidians of other authors

[203] See Transactions of the Medical and Physical Society of Calcutta, vol. ii. p. 151; or Edinburgh Journal of Science, July 1828, vol. ix. p. 143.

[204] Wagner's Handwörterbuch der Physiologie, vol. iii. part ii. p. 297.

[205]

If by the sense of touch we could make the two images appear one, then we should also see an object single when it is doubled by looking either at a nearer or a more distant object, or when it is made 100 by a multiplying glass; but if a man were to live a 1000 years, he would still see the two or the hundred images, though he knew there was only one object. In order to illustrate his opinion, Dr. Brown says that the two English words he conquered, excite the same idea as the one Latin world vicit. In reply to this Dr. Whewell says, "that to make this pretended illustration of any value, it ought to be true that when a person has thoroughly learned the Latin language, he can no longer distinguish any separate meaning in he and in conquered." With this assertion we cannot concur. The two words he conquered un <232> doubtedly convey the same meaning as vicit. If we unite the two words thus, heconquered or conqueredhe, we cannot doubt that the word he is as truly included in the termination it of vicit, as he is in the single word heconquered, unless it is alleged that vicit may also mean she conquered.

Dr. Brown's real mistake consists in not taking two exactly similar words, as vicit, vicit, like what he considers as the two exactly similar images. The two words pronounced in succession convey certainly only one idea, but the mind recognised the same in succession or its duplicity, just as it would do the two similar and united images, if one of them were slipped from its superposition on the other by pressing aside one of the eye-balls.

Dr. Brown's views are affected with another error, namely, in the assumption that the pictures in each eye are exactly similar.

[206] Edinburgh Transactions, vol. xiii. p. 479.

[207] There is no opposition between the impressions on the concave retina and on a concave surface of the body. If we hold up the hand vertically, and bend it into a concavity, an impression made on the upper part of the concavity, will be felt as coming from below, and an impression on the lower part of the concavity will be felt as coming from above, exactly as in the case of the concave retina.

[208] We have not noticed the additional explanation adopted by Dr. Alison, "that impressions on the upper part of the retina are impressions on the lower part of the optic lobes, i.e., of the sensorium;" because he has not told us what requires as much explanation as inverted vision, namely, why the lower part of the sensorium makes the object seem lower! Is the sensorium a plane, or a convexity, or a concavity ? If it is a concavity, a physical impression on the lower part will correspond to the top of the object, and an impression on the upper part with the bottom of it.

[209] I omit all consideration of the question, whether the choroid coat or retina is the seat of vision, or whether the foramen centrale is or is not an opening in the retina.

[210] See Edinburgh Transactions, vol. xv. p. 360.

[211] When a ray falls obliquely upon the retina (or any other surface of sensation) its action may be decomposed into two, the one lying in the surface of the membrane, and acting laterally upon the papillæ, and the other perpendicular, and acting in the direction of the axis of the papillæ, and therefore passing to the brain.

[212] See Edinburgh Transactions, vol. xv. pp. 350-353, and North British Review, vol. xvii. p. 165.

[213] Experiments and Considerations touching Colours, chap. ii. § 9, p. 19. Lond. 1664.

[214] King's Life of Locke, vol. i. pp. 404-408. Edit. 1830.

[215] Art. Accidental Colours, in the Edinburgh, Encyclopædia, vol. i. pp. 91, 92.

[216] See Phil. Trans., 1742-43, vol. xlii. p. 155.

[217] Phil. Trans. 1731, p. 147.

[218] Sprot's Hist. of the Royal Society, p. 246. Lond. 1667.

[219] The Posthumous Works of Robert Hooke, M.D., p. 503, tab. xi. fig. 2. Lond. 1705. In the description given of it by Waller, his biographer, the invention is mentioned as "an instrument for taking angles at one prospect, which he found described on a loose paper."

[220] Grant's Hist. of Physical Astronomy, p. 487; and Nautical Mag. vol. i. p. 351.

[221] See Edinburgh Journal of Science, vol. vi. p. 61; Encyclopædia Brit., Art. Microscope, vol. xv. p. 41.

[222] Newtoni Opera, tom. iv. p. 300.

[223] Sir Isaac does not seem to have afterwards described this construction.

[224] See Edinburgh Transactions, vol. ix. p. 433; and the Edinburgh Journal of Science, July 1829, No. I. new series, p. 108.

[225] See Newtoni Opera, tom. iv. p. 276.

[226] Treatise on Optics, edit. of 1853, p. 404.

[227] It is a curious fact, that "there is the same peculiarity about the preface to the Principia{.}" — Edleston's Correspondence &c. &c., pp lviii and lxxi.

[228] " Probably Slaughters' Coffee-house in St. Martin's Lane." — Edleston's Correspondence, p. lxxiv.

[229] Eloge, by Fontenelle. — Mém. Acad. Par. 1727. Hist. p. 151.

[230] The English edition was reprinted at London in 1717, 1721, and 1730, and the Latin one at London in 1719, 1721, 1728, at Lausanne in 1740, and at Padua in 1773.

[231] Biographia Brit. Art. Newton, vol. vii. p. 779.

[232] An analysis of the Lectiones Opticæ has been given by the author of the Life of Newton in the General Dictionary, vol. vii. p. 779, note; but it is by some mistake confined to the first Part, as if there were no second Part. The same mistake is committed in the Biographia Britannica, vol. v. p. 3215, note, where it is obvious that the author knew nothing of the second Part, as he calls the last portion of the first Part the "Last Section of these Lectures."

[233] See Art. Optics in Edin. Encyclopædia, vol. xv. p. 462.

[234] The Cardinal's letter is published in the work of Copernicus afterwards mentioned.

[235] These facts are recorded by Copernicus himself in the preface to his work.

[236] Nicolai Copernici Torinensis De Revolutionibus orbium cœlestium, Lib. vi. Fol. A second edition in folio appeared at Basle in 1566, and a third edition in quarto was published at Amsterdam in 1617, with notes, by Nicolas Muler, under the title of Astronomia Instaurata, &c.

[237] Copernicus died in 1543, at the age of 70.

[238] " Neque enim necesse est, eas hypotheses esse veras, imo ne verisimiles quidem, sed sufficit hoc unum, si calculum observationibus congruentem exhibeant." Ad Lectorem.

[239] Paul III., a member of the Farnese family, who held the Pontificate from 1534 to 1550. The year in which this preface was written is not known.

[240] Astronomiæ Instauratæ Progymnasmata. 1602.

[241] Published at the end of the Rudolphine Tables.

[242] These researches were published in his Prodromus Dissertationum Cosmographicorum, &c. Tubingæ, 1596, 4to.

[243] Kepler was foiled in his attempt to find out the law of refraction, afterwards discovered by Snellius. His optical discoveries will be found in his Paralipomena ad Vitellionem, Francof. 1604; and in his admirable Dioptrica. Franc. 1611.

[244] Nova Astronomia seu Physica Celestis tradita Commentariis de Motibus Stellæ Martis. Pragæ, 1609, fol.

[245] Harmonia Mundi, lib. v. Linzii, 1619, fol.

[246] Harmonia Mundi, lib. v. Linzii, 1619, fol. p. 178.

[247] Professor Moll, Journal of Royal Institution, 1831, vol. i. p. 496.

[248] Sirturus, De Telescopio. Francofurtæ, 1618.

[249] " Nescio quo fato ductus." — Sidereus Nuncius, p. 20.

[250] The satellites were observed by our celebrated countryman, Harriot, on the 17th October 1610. — See Martyrs of Science, Life of Galileo, pp. 40, 41.

[251] See Edinburgh Encyclopædia, Art. Mechanics, vol. xiii. p. 502, where we have given a copious abstract of the mechanical discoveries of Galileo.

[252] Life of Galileo, chap. vi., in the Martyrs of Science.

[253] Ismaelis Bullialdi Astronomia Philolaica. — Paris, 1645, p. 23. Sir Isaac admitted that Bullialdus here gives the true "proportion on gravity." — Letter to Halley, June 20, 1686, postscript.

[254] Theoricæ Mediæorum Planetarum ex causis physicis deuctæ A Alphonso Borellio. — Florentiæ, 1666.

[255] Newton (in his posthumous work, De Systemate Mundi, § 2, Opera, tom. iii. p. 180, and in his postscript in his letter to Halley, June 20, 1686, where he says "that Borelli did something") and Huygens have attached greater value to the views of Borelli. The last of these philosophers thus speaks of them: — " Refert Plutarchus in libro supramemorato de Facie in Orbe Lunæ, fuisse jam olim qui putaret ideo manere lunam in orbe suo, quod vis recedendi a terra, ob motum circularem, inhiberetur pari vi gravitatis, qua ad terram accedere conaretur. Idemque ævo nostro, non de luna tantum sed et planetis ceteris statuit Alphonsus Borellius, ut nempe primariis eorum gravitas esset solem versus; lunis vero ad Terram Jovem et Saturnum quos comitantur. Multoque diligentius, subtiliusque idem nuper explicuit Isaacus Newtonus, et quomodo ex his causis nascantur Planetarum orbes Elliptici, quos Keplerus excogitaverat ; in quorum foco altero Sol ponitur. Christiani Hugenii Cosmotheoros, lib. ii. ad finem. Opera, tom. ii. p. 720.

[256] Angelo Fabroni, Lettere inedite d'uomini illustri, tom. i. p. 173.

[257] Birch's Hist. of Royal Society, vol. ii. pp. 69-72.

[258] Ibid., vol. ii. pp. 90-92.

[259] This pendulum consisted of a wire fastened to the roof of the room, with a large wooden ball of lignum vitæ at the end of it. — Waller's Life of Hooke, p. xii.

[260] Waller's Life of Hooke, p. xii.; and Birch's Hist., vol. ii. p. 92.

[261] An Attempt to prove the Motion of the Earth from Observations made by Robert Hooke, 4to. See Phil. Trans., No. 101, p. 12.

[262] In quoting this passage, which Delambre admits to be very curious, we think he scarcely does justice to Hooke, when he says that what it contains is found expressly in Kepler. It is quite true that Kepler mentioned as probable the law of the squares of the distances, but he afterwards, as Delambre admits, rejected it for that of the simple distances. Hooke, on the contrary, announces it as a truth. — See Astronomie du 18me Siècle, pp. 9, 10. Clairaut has justly remarked, that the example of Hooke and Kepler shews how great is the difference between a truth conjectured or asserted, and a truth demonstrated.

[263] In 1673, Huygens had announced the relations between attractive force and velocity in circular motion.

[264] Whiston's Memoirs of his own Life, p. 37.

[265] Eratosthenes Batavus, 1617.

[266] Seaman's Practice, 1636.

[267] Mr. Rigaud remarks, that "we do not know when Norwood's determination became known to Newton, but we are certain that he was well aware of Snellius's measures quite as soon as he was of Picard's, — probably much sooner, since the specific mention of them is made in Varenius's Geography, (cap. iv., pp. 24-26, 1672,) of which he edited a new edition at Cambridge in 1672." — Historical Essay, p. 12. "Had he adopted," as Mr. Rigaud adds, "28,500 Rhinland perches, the length of a degree given by Snellius, he would have obtained for the moon's deflexion, in a minute, 15.5 feet."

[268]

Among the manuscripts of Conduit, we found the following statement regarding Newton's "resuming his former thoughts concerning the moon:" —

"In 1673, Dr. Hooke wrote to him to send him something new for the Transactions, whereupon he sent him a little dissertation to confute the common objection, that if it were true that the earth moved from east to west, all falling bodies would be left to the west; and maintained that, on the contrary, they would fall a little eastward, and, having described a curve with his hand to represent the motion of a falling body, he drew a negligent stroke with his pen, from whence Dr. Hooke took occasion to imagine that he meant the curve would be a spiral, whereupon the Doctor wrote to him that the curve would be an ellipsis, and that the body would move according to Kepler's notion, which gave Sir. Isaac Newton an occasion to <292> examine the thing thoroughly; and for the foundation of the calculus he intended, he laid down this proposition, that the areas described in equal times were equal, which, though assumed by Kepler, was not by him demonstrated, of which demonstration the first glory is due to Newton."

Immediately after this statement, Conduit adds, — " Pemberton, in his preface, mentions this in another manner," and he quotes part of that preface.

The above extraordinary story of Hooke's having considered a negligent stroke of Newton's pen as a spiral, and on that ground having charged him with maintaining that falling bodies would describe such a curve, could not have been given on Newton's authority, but must have been invented by an enemy of Hooke's. Newton himself admits, in his letter to Halley, July 27, 1686, that Hooke's "correcting his spiral occasioned his finding the theorem by which he afterwards examined the ellipsis."

In the preceding extract, the date 1673 is obviously erroneous. The document was copied for me by the late Henry Arthur Wallop Fellowes, the elder brother of the present Earl of Portsmouth, who kindly assisted me in the examination of Newton's papers, and who placed at the top of the document the words, (P. 49 in Jones,) which I cannot explain.

[269] Robison's Works, vol. ii. p. 94, 1822. Tradition is, we believe, the only authority for this anecdote. It is not supported by what is known of Newton's character.

[270] Principia, lib. i., Prop. iv., Schol.

[271] These various facts are stated in a letter from Halley to Newton, dated June 29, 1686. "According to your desire in your former, I waited upon Sir Christopher Wren, to inquire of him if he hid the first notion of the reciprocal duplicate proportion from Mr. Hooke. His answer was, that he himself very many years since had had his thoughts upon making out the planet's motions by a composition of a descent towards the sun and an impressed motion; but that at length he gave over, not finding the means of doing it. Since which time Mr. Hooke had frequently told him that he had done it, and attempted to make it out to him, but that he never was satisfied that his demonstrations were cogent. And this I know to be true, that in January 1683-4, I, having from the consideration of the sesquialterate proportion of Kepler, concluded that the centripetal force decreased in the proportion of the squares of the distances reciprocally, came on Wednesday to town (from Islington) where I met with Sir Christopher Wren and Mr. Hooke, and falling in discourse about it, Mr. Hooke affirmed that upon that principle all the laws of the celestial motions were to be demonstrated, and that he himself had done it. I declared the ill success of my attempts, and Sir Christopher to encourage the inquiry, said that he would give Mr. Hooke some two months' time to bring him a convincing demonstration thereof, and besides the honour, he of us that did it should have from him the present of a book of forty shillings. Mr. Hooke then said he had it, but that he would conceal it for some time, that others trying and failing might know how to value it when he should make it public. However, I remember that Sir Christopher was little satisfied that he could do it, and though Mr. Hooke then promised to shew it him, I do not find that in that particular he has been so good as his word."

[272] Letter to Halley, June 20, 1686. See also Rigaud's Hist. Essay, pp. 51, 52.

[273] It appears from Birch, in his Hist. of the Royal Society, vol. iii. p. 1, that Newton had written to Oldenburg a letter, dated January 6, 1673.

[274] July 14, 1686. Rigaud's Hist. Ess., App. pp. 39, 40.

[275] The erroneous calculations from his having used an incorrect measure of the earth's diameter.

[276]

In both the editions of the Commercium Epistolicum, drawn up by a committee of Newton's best friends, there occurs the following passage, which has misled several of Newton's biographers. "Anno . . . 1683, in . . . Actis Lipsicis pro mense Octobri, calculi differentialis elementa primum edidit D. Leibnitius, literis A. G. L. designatus. Anno autem 1683 ad finem vergente, D. Newtonus propositiones principales, earum quæ in Philosophiæ Principiis Mathematicis habentur Londinum misit," &c., No. LXXI. It is certain that 1684 should have been substituted for 1683. Mr. Rigaud, who justly remarks that this could not have been an error of the press, as "the argument with reference to Leibnitz would fall to the ground if 1684 were substituted for it," has endeavoured successfully to find out the cause of the mistake. In the Macclesfield Collection he found two Memoranda on the first communication of the Principia to the Royal Society, said to be "from <297> an original paper of Newton," which we presume means in Newton's handwriting. In the first the date 1683 is given, and in the second the correct date of 1684, "the 3 having been evidently altered to 4," by Newton himself, so that the editors of the Commercium Epistolicum made a grave mistake in adopting the date 1683.

Since the publication of Mr. Rigaud's Historical Essay, Mr. Edleston has thrown a new light on this subject. The two Memoranda mentioned by Mr. Rigaud are the commencement of a critique by Newton himself on three papers by Leibnitz, in the Leipsic Acts for January and February 1689. The critique, which Mr. Edleston thinks was probably written in 1712, occupied nearly six pages, and is preserved among the Lucasian Papers. The first sentence is given in four different forms. In the two first the date 1684 is used, and in the two last 1683. "Newton," says Mr. Edleston, "first of all clearly wrote 1684, then altered the 4 to a 3, afterwards crossed all the figures out, and wrote distinctly 1683 . . . . Newton, therefore, after endeavouring to recollect the exact year in which he sent up the fundamental proposition of the Principia to London, antedated the event by a twelvemonth," so that no blame can be cast upon the editors of the Commercium Epistolicum, for the erroneous date which they adopted. The critique is given by Mr. Edleston in his Appendix, p. 307. See Rigaud's Hist. Essay, pp. 16-18, and his Appendix, No. xix.

[277] We have given this account of Halley's interview with Newton, nearly as we find it in Conduit's manuscript, in which May is erroneously mentioned as the time of Halley's visit. Halley's own account is more brief: — "The August following <298> when I did myself the honour to visit you, I then learned the good news that you had brought the demonstration to perfection, and you were pleased to promise me a copy thereof, which I received with a great deal of satisfaction from Mr. Paget." — Letter to Newton, June 29, 1686.

[278] " Dr. Halley has often valued himself to me," says Conduit, "for being the Ulysses which produced this Achilles."

[279] Mr. Paget was Mathematical Master in Christ's Hospital. He was a friend of Newton's, and was recommended by him to Flamsteed on the 3d April, 1682, as a competitor for the Mastership. Flamsteed joined in the recommendation, and after his appointment found him "an able mathematician." He gave such satisfaction to the Governors indeed, that they sent Flamsteed "a staff," and made him one of their number. Flamsteed has left it on record that this accomplished young man, before seven years had expired, became a drunkard, neglected his duties, lost his character, and banished himself to India. What a lesson to the young who are accidentally associated with great men after whom posterity inquire! As the bearer of the germ of the Principia to Halley, Paget's name has for nearly two centuries been mentioned with honour. As a protégé of Newton and Flamsteed, who failed in justifying their recommendation, a blot has been left upon his name, which but for that honour would never have been known. See Baily's Flamsteed, p. 125.

[280] Mr. Rigaud has published it in his Historical Essay. He is of opinion that it is not the same paper, a copy of which was brought to Halley by Mr. Paget in November 1684, on the ground that that paper was never mentioned to the Royal Society by Halley, and that Halley did not see the "curious treatise De Motu till his second visit to Cambridge, in November or December 1684." Mr. Edleston, <300> however, is of opinion that the treatise De Motu was part of the lectures delivered by Newton as Lucasian Professor, which commenced in October 1684, and a copy of which is preserved in the University library; and that the paper sent to Halley in November was the germ of this treatise, and the one registered by Mr. Aston. In a letter from Cotes to Jones, published in Edleston's Correspondence, p. 209, it is stated that the manuscript at Cambridge was "the first draught of the Principia," as Newton read it in his lectures, — a statement to which Mr. Edleston refers in support of his opinion. There are certainly expressions in the letters both of Newton and Halley unfavourable to both these opinions, but we think that the following view of the question is the most probable. Halley went to Cambridge to learn if Newton had a demonstration of the proposition that a force varying reciprocally with the square of the distance would produce a motion in an ellipsis. Newton told him that he "had brought this demonstration to perfection," but that having mislaid it, he would send him "a copy thereof." This copy was sent to Halley in November obviously for his own information. Halley does not lay it before the Society, but is so pleased with it, that he goes again to Cambridge in order to "confer with Newton about it." He now saw the treatise De Motu which Newton promised to send to the Society, and which was registered. Now when Halley says (letter to Newton, June 29, 1686) that he went to Newton to confer with him about it, that is, the demonstration, and adds immediately, "since which time it has been entered upon the register books of the Society," he can only mean that the demonstration was entered as part of the treatise De Motu, of which it was certainly the leading feature. If the two its mean the same thing, then Halley received in November the same treatise that was afterwards sent to Aston in the following February, which is scarcely admissible even upon Mr. Edleston's conjecture that Halley did produce the paper on the 10th December, though the fact is not recorded in the journal book. In Newton's letter to Halley, July 14, 1686, he says, that having tried the calculation in the Ellipsis, he had thrown them by for about five years, till upon Dr. Halley's request "he sought for that paper, (namely, the calculation in the Ellipsis,) and not finding it, did it again, and reduced it into the propositions (we read proposition) showed you by Mr. Paget." — See Rigaud's Hist. Essay, p. 14, and Edleston's Correspondance, pp. lv. and 209.

[281] See Baily's Flamsteed, p. 50, note.

[282] This letter is not extant, but its date and character appear from Newton's answer.

[283] Mr. Baily, whose views respecting the quarrel which subsequently arose between Newton and Flamsteed, we shall afterwards have occasion to controvert, acknowledges that he cannot find in these two letters of Newton "any foundation for Flamsteed's censure." It is very obvious, indeed, from the highly complimentary terms in which Flamsteed at this time wrote to Newton, that he did not consider Newton as "magisterially ridiculing his opinions."

[284] At this time, and even in 1684, when he wrote his treatise De Motu, Newton had very erroneous views regarding the motions of comets; and it was not till September 19, 1685, that he acknowledged, in a letter to Flamsteed, that "it seemed very probable that the comets of November and December were the same comet." In the first edition of the Principia, p. 494, he went farther, and acknowledged that Flamsteed was right. In giving an account of the treatise De Motu, Mr. Rigaud thus speaks of Newton's views respecting the motions of comets: — " He certainly at this time had not resolved the difficult question of the paths of comets. In the Arithmetica Universalis, (Prob. 56,), he had proceeded on their supposed uniform rectilinear motion, and, in the present case, he still holds expressly to that earlier theory. How, under such conditions, (if strictly adhered to,) they could return, is not easy to understand; but waving this question, his reasoning seems to show that if they did, they might be recognised by a similarity in their motions. To determine this, he proposes to reduce the places of the comet to analogous points in an imaginary ellipse, of which the focus is occupied by the sun; and these places having been calculated by means of the auxiliary curve, were to be verified by their application to the rectilinear path. It seems wonderful, when we consider his extraordinary acuteness, that such an hypothesis did not immediately lead him to the truth; but as he so repeatedly and so distinctly describes the supposed motion of the comet to be in a straight line, it is impossible not to conclude, that even his most powerful mind required the assistance of time to emancipate itself from preconceived opinions." — Rigaud's Hist. Essay, p. 29.

[285] The dates of these letters, which are published in the General Dictionary, vol. vii. pp. 793-797, are, September 19, 1685; September 25, 1685; October 14, 1685; December 30, 1685 (?); January (?) 1686; September 3, 1686. Excepting the second, which is from Flamsteed, they are all from Newton.

[286] This letter has no date, but Flamsteed says that it was written about 1685, or January 1685-86.

[287] Edleston's Correspondence, &c., p. xxix.; and Newton's letter to Halley, June 20, 1686.

[288] Phil. Trans., 1686, pp. 6-8.

[289] We here express the opinion of Mr. Rigaud, who, after a careful and repeated examination of the Royal Society's minutes, from 1686 to 1699, "ventures to say," that "there is no notice of any pecuniary aid having been extended to the Principia." Halley was a married man with a family, and at "a considerable pecuniary risk provided for the disbursement, precisely at that period of his life when he could least afford it." — Rigaud's Hist. Essay, pp. 33-37.

[290] June 20,1686. Appendix, No. IX.

[291] It was not expressed in the letter, as Newton afterwards admits. See Appendix, No. X. Letter, July 27, 1686.

[292] The manuscript of the Principia, without the preface, bound in one volume, is in the possession of the Royal Society. Mr. Edleston is of opinion that the manuscript is not in Newton's autograph, and he believes it to be by the same hand as the first draught of the Principia in the University library, the author's own handwriting being easily recognised in the additions and alterations in both manuscripts. Edleston's Correspondence, &c{.}, pp. lvii. lviii. In a very interesting letter from Dr. Humphrey Newton to Conduitt, which is printed in our second volume, p. 91, he informs him, that "he copied out the Principia before it went to press." Pemberton states that the Principia was written in a year and a half. "Sir Isaac Newton says in one of his papers, that he wrote the Principia in seventeen or eighteen months, beginning the end of December 1684, and sending it to the Society in May 1686, except about ten or twelve of the propositions, which were composed before, viz., two in 1679, and the rest in June and July 1684." — Conduitt's MS. See p. 471.

[293] A copy of the Principia was presented to the King by Halley, accompanied with a paper giving a general account of the Book, and more especially an explanation of the notes, a subject in which the King was likely to take a deep interest, from his having as Lord High Admiral commanded the British fleet in the war with the United Provinces. See Phil. Trans., vol. xix. p. 445, and Rigaud's Hist. Essay, App. p. 77.

[294] See Appendix, No. XI.

[295] The number of copies printed is not known. The original price seems to have been ten shillings.

[296] See Rigaud's Hist. Essay, pp. 89-95.

[297] Correspondence, &c., Præf. p. xi.

[298] Ibid. Præf. p. xiv.

[299] Baily's Flamsteed, p. 138.

[300] It would appear from a conversation between Sir Isaac and Conduitt, that Bentley was at the expense of printing the second edition of the Principia, and received the profits of the work. "I asking him, (Newton,") says Conduitt, "how he came to let Bentley print his Principia, which he did not understand — 'Why,' said he, 'he was covetous, and I let him do it to get money.' " — Conduitt's MS. See vol. ii. pp. 248-254.

[301] Monk's Life of Bentley, p, 180.

[302] These letters, relating to questions connected with the new edition of the Principia, are seventy-two in number, and extend from May 21, 1709, to March 31, 1713. Mr. Edleston has added other fifty, connected with the Principia, from Newton, Cotes, Keill, Jones, Brook Taylor, and others, and in an Appendix he has published thirty-four letters, chiefly from Newton, and collected principally from original sources. Mr. Edleston has enriched this valuable work with an excellent synoptical view of Newton's life, and a large number of notes of the highest interest.

[303] The critique by Newton, already mentioned, bore upon this paper by Leibnitz, see p. 296, Note.

[304] Some account of this interesting and distinguished person, whose name is so indissolubly associated with that of Newton, and with the Principia, will be found in Appendix, No. XII.

[305] A third edition of the Principia was published in 1726, by Dr. Henry Pemberton, from materials furnished by Newton himself. Pemberton tells us that he had much personal intercourse with Newton, and that "a great number of letters passed between them on this account." This correspondence, however, has been lost. It is stated in Conduit's manuscript, that Sir Isaac "gave Pemberton two hundred guineas for printing his Principia," and that he had 3000 subscriptions at a guinea each for his "View of Sir Isaac Newton's Philosophy," published in 1728.

[306] The celebrated Lagrange, who frequently asserted that Newton was the greatest genius that ever existed, used to add — and the most fortunate, for we cannot find more than once a system of the world to establish. — Delambre, Notice sur la Vie de Lagrange, Mém. de l'Institut. 1812, p. xlv.

[307] This was first observed by Richer, who found that a clock regulated to mean time at Paris lost 2′28″ daily at Cayenne.

[308] Newton made it only 1° 31′ 28″, just one-half of its real value. Clairaut obtained the same result, but afterwards, by a more accurate calculation, found it to be 3° 4′, agreeing exactly with observation.

[309] Mém. Acad. Par. 1720.

[310] In 1738 Voltaire published a popular exposition of Newton's discoveries, which contributed greatly to their reception on the Continent.

[311] Whiston's Memoirs of his own Life," p. 36.

[312]

It does not appear at what time the Newtonian Philosophy was received at Oxford. Judging from Addison's "Oration in Defence of the New Philosophy," spoken in the Theatre at Oxford, July 7, 1693, six years after the publication of the Principia, we have no doubt that the Cartesian Philosophy, which is obviously the "New Philosophy," defended by Addison, was in full force at that date. This oration, "done from the Latin original," is appended to the English translation of Fontenelle on the Plurality of Worlds ; and on the title-page to that work it is called "Mr. Addison's Defence on the Newtonian Philosophy." Our readers will decide from the following extract whether the New Philosophy means the Newtonian or the Cartesian Philosophy : —

"How long, gentlemen of the University, shall we slavishly tread in the steps of the ancients, and be afraid of being wiser than our ancestors? How long shall we religiously worship the triflings of antiquity as some do old wives' stories? It is indeed shameful, when we survey the great ornament of the present age, (Newton,) to transfer our applauses to the ancients, and to take pains to search into ages past for persons fit for panegyrick." So far the New Philosophy may mean that of Newton, but the following passage contradicts any such inference : — "The ancient philosophy has had more allowed than it could reasonably pretend to; how often has Sheldon's Theatre rung with encomia on the Stagyrite, who, greater than his own Alexander, has long, unopposed, triumphed in our school desks, and had the whole world for his pupils? At length rose Cartesius, a happier genius, who has bravely asserted the truth against the united force of all opposers, and has brought on the stage a new method of philosophizing. But shall we stigmatize with the name of novelty, that philosophy which, though but lately revived, is more ancient than the peripatetic, and as old as the mother from whence it is derived ? A great man <335> indeed he was, and the only one we envy France, (Descartes.) He solved the difficulties of the universe almost as well as if he had been its architect." The name of Newton or his philosophy is never again mentioned. — Author.

[313] Dr. Reid states, that James Gregory, Professor of Philosophy at St. Andrews, printed a Thesis at Edinburgh in 1690, containing twenty-five positions, of which twenty-two were a compend of Newton's Principia.

[314] Cotes states in his preface to the second edition of the Principia, that copies of the first edition were scarce, and could only be obtained at an immense price. Sir William Brown, when at college, gave more than two guineas for a copy, and owing to the difficulty of procuring one at a reasonable price, the father of Dr. John Moore of Glasgow transcribed the whole work with his own bind. See Nichol's Literary Anecdotes, vol. iii. p. 322, and Encyc. Brit., Art. Moore.

[315] See the Museum Criticum, vol. ii. p. 514.

[316] The following passage in Whiston's Life of Dr. Clarke, is not in accordance with some of the preceding statements. "About the year 1697, while I was chaplain to Dr. John Moor, then Bishop of Norwich, I met at one of the coffee-houses in the market-place at Norwich, a young man, to me then wholly unknown ; his name was Clarke, pupil to that eminent and careful tutor, Mr. Ellis, of Gonvil and Caius College in Cambridge. Mr. Clarke knew me so far at the university, I being about eight years elder than himself, and so far knew the nature and success of my studies, as to enter into a conversation with me about that system of Cartesian philosophy his tutor had put him to translate, — I mean Rohault's Physics; and to ask my opinion about the fitness of such a translation. I well remember the answer I made him, that, 'since the youth of the university must have, at present, some system of Natural Philosophy for their studies and exercises; and since the true system of Sir Isaac Newton's was not yet made easy enough for the purpose; it was not improper, for their sakes, yet to translate and use the system of Rohault, (who was esteemed the best expositor of Descartes,) but that as soon as Sir Isaac Newton's philosophy came to be better known, that only ought to be taught, and the other dropped.' Which last part of my advice, by the way, has not been followed, as it ought to have been, in that university: But, as Bishop Hoadley truly observes, Dr. Clarke's Rohault is still the principal book for the young students there. Though such an observation be no way to the honour of the tutors in that university, who, in reading Rohault, do only read a philosophical romance to their pupils, almost perpetually contradicted by the better notes thereto belonging. And certainly to use Cartesian fictitious hypotheses at this time of day, after the principal parts of Sir Isaac Newton's certain system have been made easy enough for the understanding of ordinary mathematicians, is like the continuing to eat old acorns after the discovery of new wheat, for the food of mankind. However, upon this occasion, Mr. Clarke and I fell into a discourse about the wonderful discoveries made in Sir Isaac Newton's philosophy ; — and the result of that discourse was, that I was greatly surprised that so young a man as Mr. Clarke then was, not much I think above twenty-two years of age, should know so much of those sublime discoveries which were then almost a secret to all, but to a few particular mathematicians."

[317] Preface to Desaguliers' Course of Experimental Philosophy, vol. i. p. viii. Dr. Desaguliers says that he was told this anecdote several times by Sir Isaac Newton himself.

[318] The Life of John Locke. Edit. 1830, vol. i. pp. 389-400.

[319] Principia, lib. i. prop. i.

[320] Principia, lib. i. prop. xi.

[321] See Appendix, No. XIII. The original of these directions was given by Richard Cumberland, the relation of Bentley, to Trinity College, along with the originals of the five celebrated letters from Newton to Bentley, to which our attention will be afterwards directed.

[322] Lord Aston, "a great lover of the mathematics, who would gladly be satisfied in a difficulty or two on that science," requested Mr. Greves and Sir E. Southcote to submit these difficulties to Sir Isaac Newton. Mr. Greves accordingly went on Monday, the 30th November 1702, and gives the following account of the conversation. "He owns there are a great many faults in his book, and has crossed it and interleaved it, and writ in the margin of it, in a great many places. It is talked he designs to reprint it, though he would not own it. I asked him about his proof of a vacuum, and said that if there is such a matter as escapes through the pores of all sensible bodies, this could not be weighed ….. I find he design to alter that part, for he has writ on the margin, Materia sensibilis; perceiving his reasons do not conclude in all matter whatsoever." — Edleston's Correspondence, Pref. p. xiv., and Tixall's Letters, II. 152, quoted there.

[323] Improvement of the mind, Part I. chap. xx. Art. vi. and xvi., or his Works, vol. v. pp. 301, 306.

[324] These lectures were first published in Latin in 1718, and afterwards in English in 1721 and 1739, under the title of An Introduction to the true Astronomy, or Astronomical Lectures, read in the Astronomical School of the University of Oxford. by John Keill, M.D., F.R.S.

[325] Desauglier's, ut supra, Preface, pp. viii, x.

[326] Phil. Trans. vol. xvi. p. 296.

[327] Systéme du Monde, Edit. 2de, 1799, p. 336.

[328] Systéme du Monde, p. 336.

[329] Ibid., p. 340.

[330] Professor Playfair adds, that this was "the more remarkable, as the interests of navigation were deeply involved in the question of the lunar theory, so that no motive which a regard to reputation or to interest could create was wanting to engage the mathematicians of England in the inquiry." — Edinburgh Review, vol. xi., p. 280. Jan. 1808.

[331] History of Physical Astronomy, &c., p. 108. London, 1852. Mr. Grant also remarks, "that with the exception of Maclaurin and Thomas Simpson, hardly any individual of these islands deserves even to be mentioned in connexion with the history of physical astronomy during that period ;" and that, at the beginning of <348> the present century, "there was hardly an individual in this country who possessed an intimate acquaintance with the methods of investigation which had conducted the foreign mathematicians to so many sublime results."

[332]

Referring our readers to the statement at the end of Chapter IV., as showing the probable cause of the success of the French mathematicians, and of the inglorious failure of our own, we beg their attention to the following confirmation of our views by one of the wisest and most eminent of our Scottish mathematicians. In a review of Laplace's Systéme du Monde, Professor Playfair makes the following observations.

"The literary institution which has most completely produced its effect of any in modern times, and that has been most successful in promoting the interests of science, is that of the Royal Academy of Sciences of Paris, where small pensions and great honours, bestowed on a few men for devoting themselves exclusively to works of invention and discovery, have been the means of advancing the mathematical sciences in France to a state of unexampled prosperity.

"In England, where such an institution as that just mentioned was wanting, and where the public is perpetually prepared, with the question cui bono, to repress what seems the luxury of science, the same progress has not been made ; and our mercantile prejudices have so far defeated our own purpose, that if the matter had been left to us, the theory of the moon's motion would still have been extremely imperfect, and the great nautical problem of finding the longitude could have received nothing like an accurate solution." — Edinburgh Review, vol. xv. p. 39. Jan. 1810.

[333] See the Article Mathematics in the Edinburgh Encyclopædia, vol. xiii. p. 380, where Sir John Herschel pronounces a beautiful eulogium on the conduct of Euler.

[334] M. Leverrier has recently shewn that the earth's eccentricity will diminish during the period of twenty-four thousand years!

[335] History of Physical Astronomy, pp. 63, 64.

[336] Edinburgh Review, vol. xi. p. 261.

[337] The Academy of Sciences proposed the moon's acceleration as the subject of their prize for 1770. Euler gained it, but came to the conclusion that it was not produced by the force of gravity. The same subject was again proposed in 1772, and the prize was divided between Euler and Lagrange. Euler ascribed the acceleration to a resisting medium, and Lagrange evaded the difficulty. The prize was again offered in 1774, and was gained by Lagrange, and he now doubted the existence of the inequality. It was under these circumstances that Laplace took up the ect, and obtained the results which we have mentioned.

[338] Mécanique Céleste, tom. ii., liv. iii., chap. v.; and Système du Monde, liv. iv., chap. vii.

[339] Mécanique Céleste, part i., liv. iv., chap. i., tom. ii., p. 171; and Système du Monde, liv. iv., chap. x., p. 248.

[340] See Mécanique Céleste, part i., liv. iv., chap. ii., tom. ii., p. 204; and Système du Monde, liv. iv., chap. xi., p. 265.

[341] Système du Monde, liv. iv., chap. xiii., pp. 276, 277. See also Mécanique Céleste, part i., liv. v., chap. i., tom. ii., p. 347.

[342] Mécanique Céleste, tom. ii., pp. 354, 355.

[343] Laplace has shewn that the stability of the equilibrium of the rings requires that they be irregular solids, unequally wide in different parts of their circumference, so that their centres of gravity do not coincide with their centres of figure. — See Mécanique Céleste, part i., liv. iii., chap. vi., tom. ii., p. 155; Système du Monde, liv. iv., chap. viii., p. 242.

[344] Considérations sur l'ensemble du Système des petites Planètes situées entre Mars et Jupiter par M. U. J. Leverrier. Lu 28 Nov. 1853. Comptes Rendus, &c., tom. xxxvii. pp. 793-798.

[345] M. Leverrier takes occasion to remark, "that we might perhaps find some systematic difference between the mean direction of the ascending nodes of the planets near the Sun, and that of the ascending nodes of the more distant planets, and that we may thus conjecture that these planets belong in reality to three distinct groups." — Comptes Rendus, &c., tom. xxxvii. p. 795.

[346] Sir John Herschel has ventured to say, "that the orbit of Biela's comet so nearly intersects that of the Earth, that an actual collision is not impossible, and indeed (supposing neither orbit variable) must, in all likelihood, happen in the lapse of some millions of years." — Outlines of Astronomy, § 585.

[347] This comet ought to have appeared thirteen times since 1770, and, as it has not been since seen, it must be lost. Burckhardt supposed that it might have become a satellite to Jupiter, from its aphelion being near that planet!

[348] A table of the elements of their orbits is given by Sir John Herschel in his Outlines of Astronomy, § 843.

[349] M. Madler has adduced an instance, (p Ophiuchi,) where he regards the deviations from an elliptic orbit too considerable to be accounted for by an error of observation ; but we cannot view a single fact of this kind as affecting the generality of the law of gravity.

[350] M. Prévost, who used Mayer's proper motions, made the right ascension only 230°.

[351] Etudes d'Astronomie Stellaire, of which we have given a copious abstract in the North British Review, vol. viii. pp. 523-534.

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