We can, if we please, get along Annales 162 without the notion of electric and magnetic fields. It is important to specify the sense of this affirmation. In the theory of light, for example, everything thus represented with regard to Lorentz's theory can be derived from elementary actions between ions in the luminous source, the ones in the dielectrics or conductors which constitute the optical display, and finally the ones in the retina or photographic plate which receives the impression. Thus, we are accustomed, for example, to describe the phenomena of diffraction that we observe in the case of a slit used with a screen by considering with Fresnel that the points of ether situated in the slit as so many centers of disturbance. This does not conform to the equation for retarded potentials though.
Electric charges are the only points of origin for waves.
It wouldn't be allowed any longer to say that the field is a purely mathematical intermediate which we could do without, if it were possible to perceive its existence in a region of ether without placing any matter in the region. Interference experiments would have put this speed into evidence. The hypothesis of all these motions, on the other hand, has not lent itself to any plausible mechanical explanation of electrical actions in their effects. We can even, after we have established the simple formulae that describe the motions of the particles, leave out the reasoning that spawned them and consider looking at these formulae as expressing a fundamental law comparable with those of Weber and Clausius. We can easily see that the notion of field introduces the notion of absolute motion as soon as the velocities come into play, either in the field expressions or in the expression for its action on bodies.