retches from the
North pole of the sun to the South pole, there will ever be an electric
vibration, which is put into motion by the elasticity of the aetherial
vortex atoms. So that on every side of the sun there is ever going on
this electric vibration, along the lines of force which correspond to a
section of the aetherial shell, the surface of which really constitutes
the wave front.

Therefore it can readily be seen, that, as these lines are at right
angles to the propagation of the ray of light, the electric vibration is
at right angles to the lines of propagation, and is thus in accordance
with the result demanded by Maxwell's theory.

We have now to give a physical conception of the magnetic vibration or
motion of the Aether, and this has to be at right angles to both the
electric vibration and the line of propagation.

In Art. 91 we have learned that the Aether possesses a rotatory motion, by
which it rotates round the central body of the solar system, the sun. So
that if we take any point, for example, in the path of the ray as _S_{1},
_S_{2}, _S_{3}, and _S_{4}, situated upon some definite equipotential
surface or lines of force, and if we will imagine those lines to rotate
round the sun, as the sun rotates on its axis, then in time the points
will have described half the circle, and will come to the position on the
right of the sun indicated by the same Nos. _S_{1}, _S_{2}, _S_{3},
_S_{4}. Thus there has been an aetherial motion at right angles to the
electric motion, as the Aether circulates round the sun, because this
motion may be represented as taking place from west to east of the sun,
while the electric vibration takes place from north to south, or
transverse to the line of propagation.

We have, however, learned that the Aether has an electro-magnetic basis,
and therefore the rotation of the Aether gives rise to electro-magnetic
currents; hence the motion west to east is really the motion of
electro-magnetic currents which circulate round the sun. As these are at
right angles to the line of propagation, and we have seen that they are
at right angles to the electric vibration, it follows that all three are
at right angles to each other, which is in accordance with the
requirements as laid down by Maxwell.

We have considered these vibrations, first, from the view of the solar
system as a whole in its relation to the universal Aether; but the same
principle holds good if considered from the aetheria