On a Method of Making a Direct Comparison of Electrostatic with Electromagnetic Force [Abstract], pp. 449-450 in: Proceedings of the Royal Society, Vol. XVI, No. 103, June 18, 1868. EXPERIMENTAL PROOF THAT LIGHT IS AN ELECTROMAGNETIC WAVE

MAXWELL, James Clerk

Published by London: Taylor & Francis, 1868

First edition, journal issue in original printed wrappers, of the Abstract of the last of Maxwell's five important papers on the foundations of electromagnetic theory published between 1855 and 1868. In this paper Maxwell finally gives experimental proof that light consists of electromagnetic waves, which he had postulated in his fourth paper, the epoch-making 'A dynamical theory of the electromagnetic field' (1865). "[Michael] Faraday (1791-1867) had abandoned the notion of 'action at a distance' for the concept of the 'fields of force' surrounding bodies by which they act upon one another electromagnetically . . . Clerk Maxwell (1831-79), who may well be judged the greatest theoretical physicist of the nineteenth century, was happy to acknowledge his debt to Faraday; for what he did was to construct the mathematical theory of the field . . . the developed field-theory, expressed in twenty equations, was purely and elegantly mathematical" (PMM 355). In 'A dynamical theory' Maxwell showed that electromagnetic waves should propagate with a speed equal to the ratio of the electrostatic and electromagnetic units of charge. To prove his postulate on the nature of light, it was therefore necessary to accurately measure this ratio and compare it with direct measurements of the speed of light. Maxwell describes this experiment and its results in the present paper: he finds that the ratio is about 3% below the speed of light according to a recent measurement by the French physicist Léon Foucault (1819-68). The full version of this paper was published in the Philosophical Transactions (Vol. 158, pp. 643-657). Although that volume of the Phil. Trans. is 'for 1868', it is dated 1869 on the title page, so the present Abstract waa published at least six months earlier than the Phil. Trans. article. 8vo, pp. 419-482, lxxi-lxxviii. Original printed wrappers, stiched as issued (wrappers detached, rear wrapper chipped at inner edge, spine perished). Still a good to very good copy of a very fragile book. Seller Inventory # ABE-1689115527334

Bibliographic Details

Title: On a Method of Making a Direct Comparison of...
Publisher: London: Taylor & Francis
Publication Date: 1868
Binding: Soft cover
Condition: Very Good
Edition: 1st Edition