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Opticks is a book written by English
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 physicist Isaac Newton
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...

 that was released to the public in 1704. It is about optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...

 and the refraction
Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...

 of light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

, and is considered one of the great works of science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

 in history. Opticks was Newton's second major book on physical science.


The publication of Opticks represented a major contribution to science, different from but in some ways rivaling the Principia
Philosophiae Naturalis Principia Mathematica
Philosophiæ Naturalis Principia Mathematica, Latin for "Mathematical Principles of Natural Philosophy", often referred to as simply the Principia, is a work in three books by Sir Isaac Newton, first published 5 July 1687. Newton also published two further editions, in 1713 and 1726...

. Opticks is largely a record of experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...

s and the deduction
Deductive reasoning
Deductive reasoning, also called deductive logic, is reasoning which constructs or evaluates deductive arguments. Deductive arguments are attempts to show that a conclusion necessarily follows from a set of premises or hypothesis...

s made from them, covering a wide range of topics in what was later to be known as physical optics
Physical optics
In physics, physical optics, or wave optics, is the branch of optics which studies interference, diffraction, polarization, and other phenomena for which the ray approximation of geometric optics is not valid...

. That is, this work is not a geometric
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....

 discussion of catoptrics
Catoptrics deals with the phenomena of reflected light and image-forming optical systems using mirrors. From the Greek κατοπτρικός ....

 or dioptrics
Dioptrics is the study of the refraction of light, especially by lenses. Telescopes that create their image with an objective that is a convex lens are said to be "dioptric" telescopes....

, the traditional subjects of reflection
Reflection (physics)
Reflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...

 of light by mirror
A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection...

s of different shapes and the exploration of how light is "bent" as it passes from one medium
Medium (optics)
An optical medium is material through which electromagnetic waves propagate. It is a form of transmission medium. The permittivity and permeability of the medium define how electromagnetic waves propagate in it...

, such as air, into another, such as water or glass. Rather, the Opticks is a study of the nature of light and colour and the various phenomena of diffraction
Diffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...

, which Newton called the "inflexion" of light.

In this book Newton sets forth in full his experiments, first reported in 1672, on dispersion
Dispersion (optics)
In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency.Media having such a property are termed dispersive media...

, or the separation of light into a spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...

 of its component colours. He shows how colours arise from selective absorption, reflection, or transmission
In optics and spectroscopy, transmittance is the fraction of incident light at a specified wavelength that passes through a sample. A related term is absorptance, or absorption factor, which is the fraction of radiation absorbed by a sample at a specified wavelength...

 of the various component parts of the incident light. His experiments on these subjects and on the problems of diffraction (which he never fully mastered) set the subject of optics on a new level.

Newton's contribution to prismatic dispersion
Dispersive prism
In optics, a dispersive prism is a type of optical prism, normally having the shape of a geometrical triangular prism. It is the most widely-known type of optical prism, although perhaps not the most common in actual use. Triangular prisms are used to disperse light, that is, to break light up into...

 was remarkable since he outlined qualitatively multiple-prism configurations. Multiple-prism arrays, as beam expanders, became central to the design of the tunable laser
Tunable laser
A tunable laser is a laser whose wavelength of operation can be altered in a controlled manner. While all laser gain media allow small shifts in output wavelength, only a few types of lasers allow continuous tuning over a significant wavelength range....

 more than 275 years later thus encouraging the development of the multiple-prism dispersion theory
Multiple-prism dispersion theory
The first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813. A modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959...


Opticks and the Principia

Opticks differs in many aspects from the Principia. First of all, it is written in English rather than Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

. Second, unlike the Principia, it is not presented in a strictly geometric form, with proposition
In logic and philosophy, the term proposition refers to either the "content" or "meaning" of a meaningful declarative sentence or the pattern of symbols, marks, or sounds that make up a meaningful declarative sentence...

s proved by mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 from either previous propositions or lemma
Lemma (mathematics)
In mathematics, a lemma is a proven proposition which is used as a stepping stone to a larger result rather than as a statement in-and-of itself...

s or first principles (or axiom
In traditional logic, an axiom or postulate is a proposition that is not proven or demonstrated but considered either to be self-evident or to define and delimit the realm of analysis. In other words, an axiom is a logical statement that is assumed to be true...

s). It does not prove its propositions by the use of ratio
In mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...

s or equation
An equation is a mathematical statement that asserts the equality of two expressions. In modern notation, this is written by placing the expressions on either side of an equals sign , for examplex + 3 = 5\,asserts that x+3 is equal to 5...

s, by the use of fluxions
Method of Fluxions
Method of Fluxions is a book by Isaac Newton. The book was completed in 1671, and published in 1736. Fluxions is Newton's term for differential calculus...

, or the tools of mathematics. Rather, the proofs generally proceed "by Experiments." In many ways, therefore, this work is a vade mecum of the experimenter's art, displaying in many examples the way to make experiments and to draw proper conclusions from them.

The Queries

See main: The Queries
The Queries
In science, The Queries or simply "Queries" is the third book to English physicist Isaac Newton's Opticks, with various numbers of Query sections or "question" sections , expanded on from 1704 to 1718, that contains Newton's final thoughts on the future puzzles of science...

Opticks concludes with a set of "Queries." In the first edition, these were sixteen such Queries; that number was increased in the Latin edition, published in 1706, and then in the revised English edition, published in 1717/18. The first set of Queries were brief, but the later ones became short essays, filling many pages. In the fourth edition of 1730, there were 31 Queries, and it was the famous "31st Query" that, over the next two hundred years, stimulated a great deal of speculation and development on theories of chemical affinity
Chemical affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds...


These Queries, especially the later ones, deal with a wide range of physical phenomena, far transcending any narrow interpretation of the subject matter of "optics." They concern the nature and transmission of heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

; the possible cause of gravity; electrical
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 phenomena; the nature of chemical action
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

; the way in which God created matter in "the Beginning;" the proper way to do science; and even the ethical
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...

 conduct of human beings. These Queries are not really questions in the ordinary sense. They are almost all posed in the negative, as rhetorical question
Rhetorical question
A rhetorical question is a figure of speech in the form of a question posed for its persuasive effect without the expectation of a reply. Rhetorical questions encourage the listener to think about what the answer to the question must be. When a speaker states, "How much longer must our people...

s. That is, Newton does not ask whether light "is" or "may be" a "body." Rather, he declares: "Is not Light a Body?" Not only does this form indicate that Newton had an answer, but that it may go on for many pages. Clearly, as Stephen Hales
Stephen Hales
Stephen Hales, FRS was an English physiologist, chemist and inventor.Hales studied the role of air and water in the maintenance of both plant and animal life. He gave accurate accounts of the movements of water in plants, and demonstrated that plants absorb air...

 (a firm Newtonian of the early eighteenth century) declared, this was Newton's mode of explaining "by Query."

Other scientists followed Newton's lead. They saw that he had been setting forth a kind of exploratory natural philosophy
Natural philosophy
Natural philosophy or the philosophy of nature , is a term applied to the study of nature and the physical universe that was dominant before the development of modern science...

 in which the primary source of knowledge was experiment. This Newtonian tradition of experimental natural philosophy was different from the one based on mathematical deductions. In this sense, Opticks established a kind of Newtonianism
Newtonianism is a doctrine that involves following the principles and using the methods of natural philosopher Isaac Newton. While Newton's influential contributions were primarily in physics and mathematics, his broad conception of the universe as being governed by rational and understandable laws...

 that in the eighteenth century rivaled in importance the mathematical natural philosophy of the Principia. Some of the primary adepts in this new philosophy were such prominent figures as Benjamin Franklin
Benjamin Franklin
Dr. Benjamin Franklin was one of the Founding Fathers of the United States. A noted polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, musician, inventor, satirist, civic activist, statesman, and diplomat...

, Antoine-Laurent Lavoisier, and James Black.

See also

  • Color
    Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...

  • Color theory
    Color theory
    In the visual arts, color theory is a body of practical guidance to color mixing and the visual impacts of specific color combinations. Although color theory principles first appeared in the writings of Leone Battista Alberti and the notebooks of Leonardo da Vinci , a tradition of "colory theory"...

  • Prism (optics)
    Prism (optics)
    In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use...

  • Theory of Colours (book)
  • Book of Optics
    Book of Optics
    The Book of Optics ; ; Latin: De Aspectibus or Opticae Thesaurus: Alhazeni Arabis; Italian: Deli Aspecti) is a seven-volume treatise on optics and other fields of study composed by the medieval Muslim scholar Alhazen .-See also:* Science in medieval Islam...

  • Elements of the Philosophy of Newton
    Elements of the Philosophy of Newton
    Elements of the Philosophy of Newton is a book written by the philosopher Voltaire in 1738 that helped to popularize the theories and thought of Isaac Newton...

  • Multiple-prism dispersion theory
    Multiple-prism dispersion theory
    The first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813. A modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959...

External links

Full and free online editions of Newton's Opticks