Catalogue Entry: OTHE00127

Chapter XI

Author: David Brewster

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

[Normalized Text] [Diplomatic Text]

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

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

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

[4] 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.

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

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

[7] 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.

[8] Astronomiæ Instauratæ Progymnasmata. 1602.

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

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

[11] 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.

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

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

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

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

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

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

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

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

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

[21] 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.

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

[23] 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.

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

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

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

[27] 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.

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

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

[30] 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.

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