Page:Electromagnetic phenomena.djvu/1

 Electromagnetic phenomena in a system moving with any velocity smaller than that of light

By Prof. H. A. Lorentz

§ 1. The problem of determining the influence exerted on electric and optical phenomena by a translation, such as all systems have in virtue of the Earth's annual motion, admits of a comparatively simple solution, so long as only those terms need be taken into account, which are proportional to the first power of the ratio between the velocity of translation w and the velocity of light c. Cases in which quantities of the second order, i.e. of the order $$\frac{w^{2}}{c^{2}}$$, may be perceptible, present more difficulties. The first example of this kind is 's well known interference-experiment, the negative result of which has led The Ether and the Earth's Atmosphere and myself to the conclusion that the dimensions of solid bodies are slightly altered by their motion through the aether.

Some new experiments in which a second order effect was sought for have recently been published. and have examined the question whether the Earth's motion may cause a body to become doubly refracting; at first sight this might be expected, if the just mentioned change of dimensions is admitted. Both physicists have however come to a negative result.

In the second place and  have endeavoured to detect a turning couple acting on a charged condenser, whose plates make a certain angle with the direction of translation. The theory