FIZEAU, ARMAND HIPPOLYTE - ANNOUNCING FIZEAU EXPERIMENT ON THE VELOCITY OF LIGHT IN MEDIA.

Sur les Hypothèses relatives a Lèther lumineux. Et sur une expérience qui parait démontrer que le mouvement des corps change la vitesse avec laquelle la lumiere se propage dans leur interieur; (Extrait par l'auteur). (The Hypotheses Relating to the Luminous Aether, and an Experiment which Appears to Demonstrate that the Motion of Bodies Alters the Velocity with which Light Propagates itself in their Interior).

Paris, Bachelier, 1851. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences", Tome 33, No 13. With htitle and titlepage to tome 33. Pp. 329-360 (entire issue offered). Fizeau's paper: pp. 349-355. A stamp on erso of titlepage. Titlepage with faint brownspots.

First appearance of this paper, the first announcment of Fizeau's results of his experiments with the velocity of light.

"It (the paper) is less famous, for some reason, than the failure of Michelson and Morley to detect the aether drag, but NO LESS SIGNIFICANT. For it showed that the velocity of light increases in a medium according to the formula, v (1 - 1/n2), where v is the velocity of the medium, and n is the refractive index"(Gillespie in "The Edge of Objecticity" p. 427). Fizeau shows that the velocity of light is higher in water flowing in the direction of the beam than that of light propagating in the direction opposite the direction of flow. The paper offered is the shorter announcement of the research, the paper in full was published later in 1859 in "Annales de Chimie et de Physique". Albert Einstein later pointed out the IMPORTENCE OF THE EXPERIMENT FOR SPECIAL RELATIVITY.
Fizeau's result was replicated by Albert Michelson and Edward Morley in 1886 repeated the experiment on a larger scale and confirmed Fizeau's results., and in 1914 it was confirmed by Pieter Zeeman. It was Arago in 1838, who suggested this "crucial experiment" to decide between the corpuscular and undulatory theories of light by comparing the speed of light in water and in air.. It vindicated the undulatory position.

It was shown by Hendrik Lorentz (1892, 1895) that the experiment can be explained by the reaction of the moving water upon the interfering waves without the need of any aether entrainment. On this occasion, Lorentz introduced a different time coordinate for moving bodies within the aether, the so called Local time (an early form of the Lorentz transformation for small velocities compared to the speed of light). In 1895, Lorentz went a step further and explained the coefficient by local time alone and without mentioning any interaction of light and matter.

Order-nr.: 47033