Excerpt from Electromagnetic Theory of Light, Vol. 1 The Ether. - The medium assumed for the propagation of light is termed ether. Since ether evidently pervades not only terrestial but interstellar space, it cannot be identical with our atmosphere. Moreover, we must assume that ether pervades all transparent bodies, but, as the behaviour of light in such bodies is different from its behaviour in the air, that the ether pervading the former is different from that of the air that is, that the properties to be assigned the ether differ for different bodies or media. These properties are evidently determined by certain unknown actions (resistances) between the material particles of the given body and the particles (elements) of the ether pervading that body they thus differ for different bodies. Consequently, opaque bodies could also be conceived as permeated by ether, and thus ether itself as pervading not only all space, both terrestial and interstellar, but all bodies 3 that is, it may be regarded as a continuous medium. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.