Opticks

Opticks is a book written by English physicist Isaac Newton that was released to the public in 1704. It about optics and the refraction of light, and is considered one of the great works of science in history.

Even if Newton had not made his better-known discoveries concerning gravity and the invention of the calculus, Opticks would have given him the reputation as one of the greatest scientists of his time.

The second of Newton's major writings on physical science was the Opticks, first published in 1704.

This work represents a major contribution to science, different from-but in some ways rivaling-the Principia. The Opticks is largely a record of experiments and the deductions made from them, covering a wide range of topics in what was later to be known as physical optics. That is, this work is not a geometric discussion of catoptrics or dioptrics, the traditional subjects of reflection of light by mirrors of different shapes and the exploration of how light is "bent" as it passes from one medium, such as air, into another, such as water or glass. Rather, the Opticks is a study of the nature of light and color and the various phenomena of diffraction, which Newton called the "inflexion" of light.

In this book Newton sets forth in full his experiments, first reported in 1672, on dispersion, or the separation of light into a spectrum of its component colors. He shows how colors arise from selective absorption, reflection, or transmission 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.

The Optics and the Principia The Opticks differs in many aspects from the Principia. First of all, it is written in English rather than Latin. Second, unlike the Principia, it is not presented in a strictly geometric form, with propositions proved by mathematics from either previous propositions or lemmas or first principles (or axioms). It does not prove its propositions by the use of ratios or equations, by the use of fluxions, 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 The 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. 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; the possible cause of gravity; electrical phenomena; the nature of chemical action; the way in which God created matter in "the Beginning;" the proper way to do science; and even the ethical conduct of human beings. These Queries are not really questions in the ordinary sense. They are almost all posed in the negative, as rhetorical questions. 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 is may go on for many pages. Clearly, as Stephen Hales (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 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, the Opticks established a kind of Newtonianism 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 giants as Benjamin Franklin, Antoine-Laurent Lavoisier, and James Black.

The Editions The Grace K. Babson Collection contains four copies of the 1704 Opticks. Why, it may be wondered, is it necessary to have more than one copy of this rare and valuable classic? A close examination and collation of these copies shows that they differ in at least one very interesting respect. After the book had been printed, Newton found a fault which seemed to him too gross to be corrected by merely adding an "erratum" at the end of the volume, which had already been printed. Accordingly, as was the practice in those, he ordered the printer to cut out a page and paste a substitute page (or cancel) onto the stub of the original. One of the Babson copies of the Opticks resembles most other copies in this regard, having the cancel instead of the original printed page, but a second copy has both the original page as well as the cancel. By means of these two copies we can trace the history of Newton's involvement in the printing of this book.

Soon after the Opticks had been published in English Newton commissioned a Latin version, which was made under his supervision by Samuel Clarke, the Clarke of the Leibniz-Clarke correspondence. The Babson Collection contains two copies of this work. These two copies reveal an interesting aspect of the change of mind of Newton immediately after the volume was printed.

In one of the letters in the Leibniz-Clarke correspondence, Leibniz declares boldly that in the "appendix" (the Queries) to Newton's Opticks of 1706, Newton said expressly that "Space is the Sensorium of God" ("l'Espace est le Sensorium de Dieu"). He thus contradicts Clarke, who had maintained that "Newton doth not say that Space is the Organ which God makes use of to perceive all things." To confute Leibniz, Clarke quotes a passage in Latin from Query XX of the Latin edition, in which Newton refers specifically to God in his infinite space, "tanquam Sensorio su," that is, "as if in his sensorium."

How could there be such a disagreement between the reading of the text of the 1706 Latin edition of the Opticks? A comparison of several copies of this edition reveals the answer. The passage quoted by Clarke occurs on a page which is cancel, pasted onto the stub of the original page. The original page, however, contains a rather different text, one in which the word "tanquam is missing. The existence of two versions of Query XX was originally discovered by Alexandre Koyré in examining the copy of this edition in the library of the Institute for Advanced Study in Princeton. The difference between these two versions are apparent at once in comparing page 315 in the two copies in the Grace K. Babson Collection. It was later found that at least sixteen copies exist in which the original page appears. Evidently the correction was either not done carefully or done after some copies of the book had been distributed. We may presume that Leibniz had gotten hold of a copy with the original page.

In 1717 Newton brought out a revised English version of the Opticks, now incorporating English versions of the queries that had been added in the Latin edition of 1706, plus some new ones. Then, in 1718, there was a second issue of this second English edition. Both issues are in the Babson Collection. No one has as yet discovered exactly why there were two issues of this second English edition of the Opticks, nor has anyone as yet compared the two issues to find out what changes, if any, were introduced by Newton into the second issue.sv:Opticks