uld have a massless medium being
composed of electrons which possess mass, and that would be a violation
of all experience, and therefore an unphilosophical statement.

APPENDIX B

The hypothesis of electricity being the fundamental basis of all matter
made in the last chapter on the "Unity of the Universe," receives
confirmation from Sir Oliver Lodge in his _Modern Views of Matter_,
where he writes, page 13: "The fundamental ingredient of which, in this
view, the whole of matter is made up, is nothing more or less than
electricity, in the form of an aggregate of an equal number of positive
and negative electric charges. This, when established, will be a
unification of matter such as has through all the ages been sought; it
goes further than had been hoped, for the substratum is not an unknown
and hypothetical protile, but the familiar electric charge."

APPENDIX C

The hypothesis that all elements have definite quantities of electricity
in them, or a definite number of electrons, as suggested on page 335,
receives added weight by the testimony of Sir Oliver Lodge in the work
already referred to. Writing on the subject, he says: "It is a
fascinating guess that the electrons constitute the fundamental
substratum of which all matter is composed. That a grouping of say 700
electrons, 350 positive and 350 negative, interleaved or interlocked in
a state of violent motion so as to produce a stable configuration under
the influence of their centrifugal inertia and their electric forces,
constitutes an atom of hydrogen. That sixteen times as many, in another
stable grouping, constitute an atom of oxygen. That some 16,000 of them
go to form an atom of sodium; about 100,000 an atom of barium; and
160,000 an atom of radium."

From these extracts, taken from _Modern Views of Matter_, the author
claims that the theory of the Aether presented to the reader in _Aether
and Gravitation_ receives added confirmation and support.

* * * * *

ERRATA

The author regrets that Professor J. J. Thomson's name has been
incorrectly spelled in several places.

INDEX

Aberration of light, 69, 149, 218

Absorption, 104-6

Acceleration, 239

Actinic rays, 141

Action at a distance, 96, 174, 176
and re-action, 20, 251

Adams' discovery of N