Fizeau's Experiment and the Principle of Relativity

Abstract

MR. CUNNINGHAM seems determined that the principle of relativity shall assert supremacy as regards the Fizeau effect on the velocity of light, arising from motion of the transmitting medium. This is a firstorder effect, while the principle of relativity was invented to account for the second order. Up to the first order the affairs of moving media hang entirely on the ascertained fundamental relations of electrodynamics; and any type of relativity which does not agree with the formula thence deduced must, if substantiated, upset our whole system of ideas.