NOTES ON THE TRANSLATION OF NEWTON’S OPTICAL MEMOIRS.

1. On January 11, 1672, Newton was elected a member of the Royal Society. At the end of a letter to the Society’s secretary, Oldenburg, dated January 18 of the same year, Newton wrote: “I should like you, in your next letter, to inform me how much longer the weekly meetings of the Society will continue. If they continue for some time yet, I should like a communication to be heard and considered there concerning a certain philosophical discovery which led me to the construction of the above-mentioned telescope; I have no doubt that it will be received with considerably greater satisfaction than the communication about the instrument; in my judgment, it is the strangest, if not the most significant, discovery that has ever been made concerning the actions of nature” (Th. Birch. The History of the R. S. of London, v. III, 5, 1757). On February 8 of the same year, at a meeting of the Society, Newton’s new letter to Oldenburg was read, constituting the first translated memoir. By resolution of the Society, the letter was printed in Philosophical Transactions No. 80, p. 3075, for February 1671/2. The Russian translation was made from the reprint in Phil. Trans. in 1809 (The Philosophical Transactions of the R. S. of London from their commencement, in 1665 to the year 1800; abridged., v. I, p. 678, 1809) and was checked against the Latin text in the edition of Newton’s optical writings cited in the preface. The exact title of the memoir is: “A Letter of Mr. Isaac Newton, Professor of Mathematics at the University of Cambridge, containing his New Theory about Light and Colours.”

2. The history of the origin of Newton’s optical works may be found, for example, in F. Rosenberger, Isaac Newton, 1895.

3. The origin of prismatic colors from the different thicknesses of the glass in a prism was explained by de Dominis (1611). The treatise of de Dominis, published in Venice in 1611, was known to Newton. Cf. Rosenberger, l. c., p. 14.

4. Concerning certain experiments proposed for testing Newton’s theory in the Society (Phil. Trans. abridged., v. I, p. 714, 1809), Newton reports the following experiment: “Having reasoned that rays coming from the planet Venus are less inclined to one another than rays from opposite parts of the solar disk, I once made one or two experiments with its light. In order that it might be sufficiently strong, I considered it necessary first to collect the light of Venus by means of a broad lens. Then, placing a prism between the lens and its focus at such a distance that the light could pass through the prism, I found that the focus, which had earlier appeared as a luminous point, stretched out into a long shining line.” The same observation is set forth in the Optical Lectures (Part One, XX).

5. The phenomenon described here by Newton is now known under the name of the “Magnus effect” and has found technical application in Flettner’s rotor ship. A modern hydrodynamic explanation of the effect may be found, for example, in the article by L. Prandtl: “The Magnus Effect and the Wind Ship” (U. F. N., 5, p. 1, 1925).

6. In connection with the objections of O. Paris, Newton later placed in Phil. Trans. a drawing illustrating the experimentum crucis, which is reproduced here without further explanation.

Fig. 1.

7. Newton’s second telescope was sent at the end of 1671 to London, and was examined by the king and by members of the Royal Society: “They formed so good an opinion of the instrument (Birch. History of R. S., v. III, p. 1), that it was resolved to send, through the secretary, a description and a diagram with a letter to Mr. Huygens, who was then in Paris, in order to secure the author’s rights.” The description of Newton’s telescope, together with Huygens’s reply, were printed in Phil. Trans. for 1672.

8. The colors of thin plates, first described in measured detail by Hooke in his Micrographia (1667).

9. Subsequently (in the Opticks) Newton changed the nomenclature of colors: by “purple” he came to mean a compound color—the result of mixing violet with red in various proportions.

10. A tincture of nephritic wood, brought from Mexico, containing, apparently, a solution of aesculin. The color of the extract in transmitted light is yellow, while in reflected light a blue fluorescence is observed, excited by the extreme violet and ultraviolet rays. In this region of the spectrum Newton scarcely carried out his experiments with monochromatic illumination. In the other parts, scattered light was obtained from particles suspended in the liquid, coinciding completely in color with the incident light. Observations on the tincture of nephritic wood were made by Kircher, Grimaldi, Boyle, Hooke, and others.

11. Newton himself was unable to repeat this experiment of Hooke’s, as is clear from the corresponding passage in the Opticks. The experiment is discussed in detail by Newton in his reply to Hooke’s criticism (Phil. Trans. abr., v. II, p. 21, 1809).

11a. In the English text—bise; in the Latin translation—pulvis caeruleus montanus (blue mountain powder).

12. This obscure and cautiously written passage was understood by Hooke as an assertion by Newton of the corporeality of light (Birch, v. III, p. 14). In his long, witty reply to Hooke, which in many respects supplements the main memoir (Phil. Trans., v. II, p. 13, 1809), Newton writes: “It is true that from my theory I infer the corporeality of light, but I do this without any decisive insistence (absolute positiveness), as is indicated by the word ‘perhaps.’ At most, this is a very probable consequence of the doctrine, but not a basic proposition, or part of one; all the propositions are collected in the preceding points. I am somewhat surprised how the critic could imagine that, having asserted the theory with the greatest rigor, I should thereafter carelessly speak of the basic proposition only as of something that ‘perhaps’ is. If such a hypothesis had entered into my intention, I would have explained it somewhere. But I knew that the properties of light which I assert may to some extent be explained

not only this one, but also many other mechanical hypotheses. Therefore I decided to reject them all and to speak of light in general terms, discussing it abstractly as something that always propagates in straight lines from luminous bodies, without defining what it is: whether it is a disordered mixture of diverse qualities, modes of bodies, the bodies themselves, or certain abilities, forces, or anything else.” In the Latin translation the last phrase of the text is rendered as: ego vero incerta certis miscere nolo.

13. Newton gave a detailed description of the collimator arrangement in the Opticks.

14. The controversy over Newton’s theory and his experiments lasted almost continuously for four years and then immediately died down. In Phil. Trans. for 1672–1676 there appeared 19 numbers by Newton and his opponents on this question. The controversy was begun by Hooke (Birch, v. III, p. 10); the last objection in time (1676) was made by Lucas (Liège), whose spectrum length proved considerably smaller than Newton’s. Newton answered his opponents at length, performed new experiments, described the details of old ones, and in the Society committees were appointed to repeat Newton’s experiments. However, the superficial polemical attacks, based to a significant degree on inept repetitions of the experiments or on a failure to understand the new theory, irritated Newton exceedingly. In March 1673 Newton intended to leave the Society; in June of the same year he asked Oldenburg, if possible, not to forward to him any objections or letters. Finally, on November 18, 1676, he wrote to Oldenburg: “I see that I have become a slave to philosophy. But when I have finished with Mr. Lucas’s affair, I shall resolutely and forever part with it, except for what I do for my own pleasure and what I shall leave for publication after my death. I have now learned that either one must not communicate anything new at all, or else one has to spend all one’s strength in defending one’s discovery.” From 1676 Newton’s name disappears from the pages of Phil. Trans. and appears again only at the end of 1679. For a detailed account of the controversy see Rosenberger. The text of the controversy is collected in the edition of Newton’s optical writings cited in the preface.

15. In a letter of November 13, 1675, Newton informed Oldenburg of his intention to send the Society a new discourse on colors. The lengthy manuscript that was received began to be read on December 9. The reading continued on December 16, January 20, and February 3 and 10. In the accompanying letter Newton wrote: “From the erasures and insertions between the lines you can see that the hypothesis was written hastily and that I did not have time to copy it out, which compels me to reserve the freedom to make additions; I should like you to return to me both this and the other articles when the need for them has passed.” During Newton’s lifetime the memoir was not printed and was published in full in the History of the Royal Society (Th. Birch, History of R. S., v. III, p. 248, 1757). The second part of the memoir was included almost in its entirety by Newton in the Opticks, with slight changes. The first part of the memoir has been translated into Russian.

16. Cf. note 12. A detailed exposition of Hooke’s objections and Newton’s reply is given by Rosenberger.

17. Newton was present at the meeting of the Society on March 11, 1675. In connection with the reading of Boyle’s discourse on the luminescence of rotting meat, there arose a dispute about the nature of light, during which Hooke expressed the following considerations (Birch, v. III, p. 193): “Light is an oscillatory or trembling motion of the medium, occurring as a consequence of a similar motion of the luminous body, like sound, which is always explained by the trembling of the medium conducting it, produced by the trembling motion of the sounding body. Just as in sound proportional vibrations produce different harmonies, so too in light different strange and pleasant colors are obtained through the mixture of proportional and harmonious motions. Some are perceived by the ear, others by the eye.” At the following meeting, on March 18, Hooke read his discourse on the nature and properties of light, based on his diffraction experiments. It may be thought that

these two meetings of the Society and served as the occasion for the emergence of Newton’s new memoir.

1. Great virtuosos.

2. Cf. the end of note 14. In his accompanying letter to Oldenburg, Newton wrote: “Sir, I had previously intended never to write hypotheses about light and colors, fearing that they would involve me in empty disputes. But I hope that the solution I have declared—not to answer everything that looks like an objection—may protect me from such dangers.”

3. Later, experiments with a pendulum in a vacuum, for the same purpose of determining the damping of oscillations in the ether, were carried out by Lambert (cf. L. Eulers und J. H. Lamberts Briefwechsel. Aus den Abh. der Preuss. Ak. d. W., No. 2, 1924).

4. In the original: phlegmatic.

5. In the original: spirits. The word spiritus was used by Newton and his contemporaries in the most varied senses. Sometimes spiritus corresponds to spirit, essence; sometimes it denotes acids; in certain cases spiritus means “spirit” in the modern sense. When Newton calls one of the kinds of ether spiritus, the word “gas” is used throughout in the translation.

6. In the original: protoplast.

7. Newton’s electrical experiments were repeated in the Society, at first unsuccessfully, then, after additional instructions from Newton (Birch, v. III, p. 261), with complete success.

8. Here we have the first indications of Newton’s work on the question of gravitation.

9. This phrase may be interpreted as the first indication of the inverse-square law.

10. In this phrase it is easy to notice the extension of the principle of gravitation to the solar system.

11. Newton subsequently abandoned this explanation of capillary phenomena (“Optics,” Query 29); in the Optics the rise of liquids in capillary tubes illustrates the presence of molecular attractions.

12. In the original: “the animal spirits are neither like the liquor, vapour, or gas of spirit of wine.” Cf. note 22.

13. Acid spirits. Cf. note 22.

14. An echo of the teaching of Descartes.

15. Cf. note 28.

16. In a letter to Oldenburg of December 14, 1675, sent immediately after the memoir concerning the electrical experiments mentioned above, Newton wrote: “I ask you to convey my respectful greetings to Mr. Boyle, if you see him, and to thank him for the conversation with which he honored me this spring. My idea of catching the ether in a trap (trepaning the common aether), as he was pleased to express it, seems to me not as ridiculous as it seemed to him (makes me begin to have the better thoughts on that he was pleased to entertain it with a smile). I hope that, if he proposes to make a series of experiments with his air pump, he will also try how compression or expansion of mercury acts upon its softening or hardening, elongation and contraction” (Birch, v. III, p. 261).

17. The derivation of this theorem is included in the Principia (Russian translation by Acad. A. N. Krylov, vol. I, p. 250 ff.).

18. The second part of the memoir being translated, later included in the Optics.

19. The front part of a wave corresponds here, for example, to the phase of compression; the rear part, to the phase of expansion. Newton incidentally passes over this important point of the hypothesis, as difficult for it as for the purely wave conception.

20. Sensorium.

1. The analogy between the spectrum and the musical scale is set forth somewhat differently in the Opticks. Concerning a modern evaluation of this analogy, cf., for example, R. Houstoun, Light and Colour, 1926, GIZ.

2. In reply to Hooke’s statement that Newton’s hypothesis coincides with his own, Newton observes: “I have nothing in common with him, except the supposition that the ether is a medium capable of vibrations; but I make use of this supposition in quite a different way from him: he supposes that the vibrations are light, whereas I suppose that this is not so. In this there is a great difference both from him and from Descartes” (Birch, vol. III, p. 279).

3. In the same year in which Newton thus estimated the upper limit for the velocity of light, Rømer’s discovery was published. The communication about this was placed in Phil. Trans. in 1677.

4. The so-called achromatic rings, obtained when Newton’s rings are viewed through a prism and by other methods. See, for example, H. Bouasse and Z. Carrière, Interférences, p. 339, 1923.

5. Hooke read to the Society about his diffraction experiments on 18 March 1675.

6. Grimaldi’s book, Physico Mathesis de Lumine, Coloribus et Iride etc. Bononiae, 1665, was reviewed in Phil. Trans. in 1672. Judging by the text of the memoir, Newton had not read Grimaldi’s treatise before that time. The author he cites, Honoré Fabri, was an Italian and a Frenchman (born in 1607 near Lyons). The title of the book used by Newton is: Dialogi Physici; quorum Primus de Lumine etc. Lugduni Galliarum, 1669. The book is not borrowed from Grimaldi, but contains objections against him.

7. Judging from the fact that Newton sets forth another person’s experiment, one may think that until the end of 1675 he himself had not performed diffraction experiments. His own experiments are set forth in the Opticks.

Responsible editors: N. N. Lazarev and E. V. Shpolsky.