Just as alterations in the electrical condition of space give rise to the appearance of a magnetic field, any alteration of the magnetic state of space gives rise to the appearance of an electrical field. This process is called electromagnetic induction. With its discovery, the generation of electricity through friction and in the galvanic way was supplemented by a third way. By this means the practical use of electricity on a large scale became possible for the first time. If our picture of the two earlier processes of generating electricity is correct, then this third way must also fit into the picture, although in this case we have no longer to do with any direct atomization of physical matter. Our picture of magnetism will indeed enable us to recognize in electromagnetic induction the same principle on which we found the two other processes to rest.