Opticks

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The first edition from 1704

Opticks: Or, a Treatise of the Reflexions, Refractions, Inflexions and Colors of Light is a scientific non-fiction book by the English natural philosopher Isaac Newton from 1704. In the book Newton analyzes the fundamental properties of light with regard to refraction in prisms and lenses , the diffraction of light in densely layered glass plates and the behavior of color mixing with spectral colors and pigment powder. Opticks was Newton's second major work in the field of natural science physics . The book is counted among the most important works in the history of science.

publication

The author explains the genesis of the book in the foreword as follows:

“Part of the ensuing Discourse about Light was written at the desire of some Gentlemen of the Royal Society, in the year 1675, an then sent to their Secretary, and read at their Meetings, and the rest was added about twelve years after to complete the theory; except the third Book, and the last Proposition of the Second, which were since put together out of scattered papers. To avoid being engaged in Disputes about these Matters, I have hitherto delayed the printing, and should still have delayed it, had not the opportunity of Friends prevailed upon me. "

“Part of the subsequent discourse on light was written at the request of some gentlemen of the Royal Society in 1675, and then sent to their secretary and read at their meetings, and the remainder was added about twelve years later to complete the theory; except for the third book and the final proposal of the second, which have since been compiled from scattered papers. So far, to avoid arguments about these matters, I have postponed the pressure and would have delayed it even more if the persistent harassment of friends hadn't made me do it. "

The book was published in English in 1704 . The author's name is missing on the cover of the first editions. A translation into school Latin by Newton's student Samuel Clarke appeared in 1706. The publication of Opticks was an important contribution to science that differed from , but in some ways competed with, Newton's first major work, Philosophiae Naturalis Principia Mathematica . The fourth English edition appeared posthumously in 1730. In 1898, the Dresden vice-principal William Abendroth translated and published a German version of the Opticks .

content

An edition from 1730

Opticks is largely a record of experiments and the conclusions drawn from them, covering a wide range of topics in later wave optics . The work is not a geometrical examination of catoptrics or dioptres , the traditional themes of the reflection of light by prisms of different shapes and the exploration of how light is refracted when it passes from one medium such as air to another such as water or glass. Rather, Opticks is a study of the nature of light and color and the various phenomena of diffraction , which Newton called the flexion of light.

In the book Newton described in detail his experiments on dispersion , the separation of light into its color spectrum , of which he reported to the Royal Society in London in 1672. He showed how the appearance of color is created through selective absorption , reflection or transmission of the various components of the incident light.

The centrality of Newton's work is that it overturned the dogma attributed to Aristotle or Theophrastus by Eresus and accepted by scholars in Newton's time, that "pure" light (like the light attributed to the sun) is fundamentally white or colorless and is changed by the interaction with matter in color by mixing with darkness. Newton proved the opposite: light is made up of different spectral hues (he describes seven: red, orange, yellow, green, blue, indigo, and purple), and all colors, including white, are produced by various mixtures of these hues. He demonstrated that color arises from a physical property of light and that each hue is refracted at a characteristic angle by a prism or a lens.

Newton also made it clear that color is a cognitive phenomenon and not an inherent property of material objects or light itself. For example, he shows that a red-violet (magenta) color can be mixed by superimposing the red and violet ends of two spectra, although this color can be mixed does not occur in the spectrum and is therefore not a light color. By connecting the red and purple ends of the spectrum with one another, he arranged all the colors in a color wheel that both quantitatively predicts the color mixture and qualitatively describes the perceived similarity of the hues.

Opticks and the Principia

Opticks differs from the Principia in many ways . The book was first published in English rather than Latin , which European philosophers normally used, and helped develop a more "popular" scientific literature. This marks a significant change in the history of the English language. With Britain's growing confidence and influence in the world, at least in part from the likes of Newton, the English language quickly became the language of science and business. The book is an example of popular science exposure : although Newton's English is a bit out of date and has a penchant for long sentences with many restrictions, the book is still easy to understand even for a modern reader. In contrast, many contemporary readers found the Principa difficult to access or understand. His formal but flexible style shows colloquial expressions and metaphorical choice of words.

In contrast to the Principia , Opticks does not build on statements about geometric properties that are either derived from previous statements, lemmas or basic concepts (or axioms). Instead, axioms define the meanings of technical terms or fundamental properties of matter and light, and the stated sentences are demonstrated through specific, carefully described experiments. The first sentence of the book states:

"My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments."

"It is not my intention in this book to explain the properties of light through hypotheses, but only to state them and to confirm them through calculation and experiment."

In an Experimentum crucis or " Kreuzesversuch " (Book I, Part II, Theorem ii) Newton showed that the light color corresponded to his "degree of breakability" (angle of refraction) and that this angle was not due to additional reflection or refraction or the passage of light can be changed by a color filter.

The book is a vademecum on the skill of the experimenter and shows many examples of how observations can be used to derive factual generalizations about the physical world and then rule out competing explanations through specific experimental tests.

In contrast to the Principia , which goes beyond the deductive method and follows the principle of Hypotheses non fingo , Opticks develops light hypotheses outside of deduction that go beyond the experimental evidence: For example, that the physical behavior of light is due to its corpuscular nature of small particles or that perceived colors are harmoniously proportioned like the notes of a diatonic scale .

The queries

Opticks ends with a set of questions ( The Queries ). In the first edition there were sixteen such questions; the number rose in the Latin edition published in 1706 and again in the revised English edition published in 1717/18. The first questions were kept short, while the later ones were formulated into short essays that filled many pages. In the fourth edition of 1730 there were 31 questions, and it was the famous 31st question that sparked much speculation and theories about chemical affinity over the next 200 years .

These questions, especially the later ones, deal with a multitude of physical phenomena that go far beyond any narrow interpretation of the subject of "optics". They concern the nature and transfer of heat ; the possible cause of gravity ; electrical phenomena; the nature of the chemical reaction ; the way in which God created matter in the "beginning"; the correct use of science; and even people's ethical behavior . The questions asked are not questions in the traditional sense. Almost all of them are asked negatively, as rhetorical questions. That is, Newton does not ask whether light “is” or has a “body”. Rather, he explains: "Is light not a body?"

reception

Opticks has been widely read and discussed in England and continental Europe . The presentation of the work at the Royal Society sparked a bitter argument between Newton and Robert Hooke over the corpuscle theory of light, which led Newton to postpone publication of the book until after Hooke's death in 1703. On the continent, and particularly in France, both the Principia and Opticks were initially rejected by many natural philosophers who continued to defend Cartesian natural philosophy and the Aristotelian ideas of color, claiming that Newton's prism experiments were difficult to reproduce. In fact, the Aristotelian theory of the fundamental nature of white light was defended well into the 19th century, for example by the German writer Johann Wolfgang von Goethe in his work " On the theory of colors ".

Newtonian science became a central theme in the attack by philosophers in the Age of Enlightenment against a natural philosophy based on the authority of ancient Greek or Roman naturalists or on the deductive reasoning of first principles (the method of the French philosopher René Descartes ) rather than the Applying mathematical reasoning to experience or experiment. Voltaire made Newtonian science known in his book Elements de la philosophie de Newton in 1738 . It was not until around 1750 that the combination of the experimental methods of the Opticks and the mathematical methods from Principia established itself as a uniform and comprehensive model of Newtonian science. Some of the followers of this new philosophy were such prominent figures as Benjamin Franklin , Antoine Laurent de Lavoisier and Joseph Black .

After Newton, many theories were revised. The English physicist Thomas Young (1773–1829) and Augustin Jean Fresnel combined Newton's particle theory with the wave theory of the Dutch physicist Christiaan Huygens to show that color is the visible manifestation of the wavelength of light. Science increasingly recognized the difference between color perception and mathematical optics.

The German poet Goethe could not shake the Newtonian foundation with his epic diatribe "On the theory of colors", but the Irish natural scientist John Tyndall noted in 1880:

“One hole Goethe did find in Newton's armor… Newton had committed himself to the doctrine that refraction without color was impossible. He therefore thought that the object glasses of telescopes must for ever remain imperfect, achromatism and refraction being incompatible. This inference was proved by Dollond to be wrong. "

“Goethe found a hole in Newton's armor… Newton had devoted himself to the teaching that refraction without color was impossible. He therefore thought that the objective lenses of telescopes must remain imperfect because achromatism and refraction are incompatible. This conclusion was refuted by Dollond . "

literature

Web links

Wikisource: Opticks  - Sources and full texts (English)
Commons : Optics  - collection of images, videos and audio files

Complete and freely accessible English editions of Newton's Opticks :

Individual evidence

  1. ^ Isaac Newton: Opticks: or, a treatise of the reflections, refractions, inflexions and colors of light. Also two treatises of the species and magnitude of curvilinear figures . Octavo, Palo Alto, California 1998, ISBN 1-891788-04-3 (annotated by Nicholas Humez).
  2. ↑ Sir Isaac Newton: Optics or Treatise on Reflections, Refractions, Diffraction and Colors of Light . Verlag von Wilhelm Engelmann, Leipzig 1898 ( archive.org - translated and edited by William Abendroth ).
  3. ^ Isaac Newton: Hydrostatics, Optics, Sound and Heat . Cambridge University Library ( cudl.lib.cam.ac.uk - Scanned manuscript in English and Latin).
  4. ^ Newton Query 31 . In. ncsu.edu . (PDF; 42.46 kB; English)
  5. ↑ John Tyndall: Goethe's color theory . In: Popular Science Monthly. Volume 17, July 1880. (English)