pposed to be constituted of aetherial atoms, or atoms of
electricity, may unite with any other vortex ring, thus producing a
vortex ring of double density, which would possess double the
electricity of the unit vortex ring. If we united three vortex rings,
then the result would be an atom of threefold the density and strength
of the unit vortex ring.

We might conceive of four or any number of these rings uniting together
to form a separate element, and then each element would simply be a
multiple of the unit vortex ring, and so possess regular multiples of
the atoms of electricity, each multiple representing a distinct element.

We will now let Professor Thomson speak for himself on the matter, and
will describe the theory in his own words, always keeping in mind the
hypothesis that the unit vortex ring is itself composed of a definite
number of atoms of electricity or electrons, as proved by Faraday. See
_Appendix C_.

In the work already referred to, Professor Thomson states: "We may
suppose that the union or pairing in this way of two vortex rings of
different kinds is what takes place, when two elements of which these
vortex rings are atoms combine chemically; while, if the vortex rings
are of the same kind, this process is what occurs when atoms combine to
form molecules. Now let us suppose that the atoms of different chemical
elements are made up of vortex rings, all of the same strength, but that
some of these elements consist of only one ring, others of two rings
linked together, others of three loops, and so on. Then if any of these
rings combine to form a permanent combination, the strength of all the
primaries in the system so formed by the combination must be equal."

"Thus an atom of one element may combine with another atom of the same
kind, to form a molecule of that substance consisting of two atoms.
Again, three of these atoms may combine, and form a system consisting of
three primary elements, but the chance of their doing so is small
compared with the chance of two pairing; so that the number of systems
of this kind will be small compared with the number of the systems
consisting only of two atoms. We might have systems of four atoms, but
the number would be small compared with the number of systems that
consist of three atoms."

"Now, suppose that an atom of one element is to combine with an atom of
another. Suppose, to fix our ideas, that the atom consisting of two
vortex rings linked together