wave; while if the electron stops suddenly, a
kind of pulsation is transmitted through the ether, and thus we obtain
Roentgen rays.

Sec. 4. NEW VIEWS ON THE CONSTITUTION OF THE ETHER AND OF MATTER

New and valuable information is thus afforded us regarding the
properties of the ether, but will this enable us to construct a
material representation of this medium which fills the universe, and
so to solve a problem which has baffled, as we have seen, the
prolonged efforts of our predecessors?

Certain scholars seem to have cherished this hope. Dr. Larmor in
particular, as we have seen, has proposed a most ingenious image, but
one which is manifestly insufficient. The present tendency of
physicists rather tends to the opposite view; since they consider
matter as a very complex object, regarding which we wrongly imagine
ourselves to be well informed because we are so much accustomed to it,
and its singular properties end by seeming natural to us. But in all
probability the ether is, in its objective reality, much more simple,
and has a better right to be considered as fundamental.

We cannot therefore, without being very illogical, define the ether by
material properties, and it is useless labour, condemned beforehand to
sterility, to endeavour to determine it by other qualities than those
of which experiment gives us direct and exact knowledge.

The ether is defined when we know, in all its points, and in magnitude
and in direction, the two fields, electric and magnetic, which may
exist in it. These two fields may vary; we speak from habit of a
movement propagated in the ether, but the phenomenon within the reach
of experiment is the propagation of these variations.

Since the electrons, considered as a modification of the ether
symmetrically distributed round a point, perfectly counterfeit that
inertia which is the fundamental property of matter, it becomes very
tempting to suppose that matter itself is composed of a more or less
complex assemblage of electrified centres in motion.

This complexity is, in general, very great, as is demonstrated by the
examination of the luminous spectra produced by the atoms, and it is
precisely because of the compensations produced between the different
movements that the essential properties of matter--the law of the
conservation of inertia, for example--are not contrary to the
hypothesis.

The forces of cohesion thus would be due to the mutual attractions
which occur in th