rge to the
mass. We then find for this relation precisely that value which we
have already met with so many times. Such a coincidence cannot be
fortuitous, and we have the right to believe that the electron
revealed by the luminous wave which emanates from it, is really the
same as the one made known to us by the study of the cathode rays and
of the radioactive substances.

However, the elementary theory does not suffice to interpret the
complications which later experiments have revealed. The physicists
most qualified to effect measurements in these delicate optical
questions--M. Cornu, Mr Preston, M. Cotton, MM. Becquerel and
Deslandres, M. Broca, Professor Michelson, and others--have pointed
out some remarkable peculiarities. Thus in some cases the number of
the component rays dissociated by the magnetic field may be very
considerable.

The great modification brought to a radiation by the Zeeman effect
may, besides, combine itself with other phenomena, and alter the light
in a still more complicated manner. A pencil of polarized light, as
demonstrated by Signori Macaluzo and Corbino, undergoes, in a magnetic
field, modifications with regard to absorption and speed of
propagation.

Some ingenious researches by M. Becquerel and M. Cotton have perfectly
elucidated all these complications from an experimental point of view.
It would not be impossible to link together all these phenomena
without adopting the electronic hypothesis, by preserving the old
optical equations as modified by the terms relating to the action of
the magnetic field. This has actually been done in some very
remarkable work by M. Voigt, but we may also, like Professor Lorentz,
look for more general theories, in which the essential image of the
electrons shall be preserved, and which will allow all the facts
revealed by experiment to be included.

We are thus led to the supposition that there is not in the atom one
vibrating electron only, but that there is to be found in it a
dynamical system comprising several material points which may be
subjected to varied movements. The neutral atom may therefore be
considered as composed of an immovable principal portion positively
charged, round which move, like satellites round a planet, several
negative electrons of very inferior mass. This conclusion leads us to
an interpretation in agreement with that which other phenomena have
already suggested.

These electrons, which thus have a variable velocity