SIR JOSEPH LARMOR has kindly pointed out to me that it is incorrect, in the interpretation of Fizeau's experiment, to assume that the velocity of propagation of light is the group velocity, so that I ...

Due to their stable design, Fizeau interferometers are used to determine the topography of surfaces such as, e.g., plane surfaces. PTB has now developed a method which makes it possible to analyze ...

The road in Paris named after French physicist Hippolyte Fizeau, as drawn by an artist in 1896. (Credit: F Séguin, Dessinateur. Musée Carnavalet, Histoire de Paris. D.10405) An 1851 experiment in ...

The beam of a laser is expanded by a telescope (expander) to illuminate a point source array (PSA). The PSA contains diffractive microlenses on its front side that focus the incoming light onto a ...

THERE was no intention in the letter to which Sir Joseph Larmor refers (NATURE, October 29, p. 226) of suggesting that the principle of relativity and the fundamental relations of electro-dynamics ...