Excerpt from The Electron Theory of Magnetism The theory, worked out by Langevin for paramagnetic gases only, was later extended by Weiss to ferromagnetic substances. Weiss introduced a new notion into the theory of magnetism, viz., that of an intrinsic or molecular magnetic field by means of which he could account in a very beautiful way for the magnetic properties of the crystal pyrrhotite and many of the magnetic properties of iron, nickel, and cobalt. He has also contributed most essentially to our experimental knowledge of the ferromagnetic phenomena. 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.