closely related phenomena of one single set of forces, and depend on
transverse vibrations of the ether. Light itself--whatever else it be--is
always and everywhere an electrical phenomenon. The ether itself is no
longer hypothetical; its existence can at any moment be demonstrated by
electrical and optical experiment. We know the length of the light wave
and the electric wave. Indeed, some physicists believe that they can even
determine approximately the density of ether. If by means of the airpump
we remove from a bell-jar the atmospheric air (except an insignificant
residue), the quantity of light within it remains unchanged; it is the
vibrating ether we see.[9] These advances in our knowledge of the ether
mean an immense gain for monistic philosophy. For they do away with the
erroneous ideas of empty space and _actio in distans_; the whole of
infinite space, in so far as it is not occupied by mass-atoms
("ponderable matter"), is filled by the ether. Our ideas of space and
time are quite other than those taught by Kant a hundred years ago; the
"critical" system of the great Koenigsberg philosopher exhibits in this
respect, as well as in his teleological view of the organic world and in
his metaphysics, dogmatic weaknesses of the most pronounced kind.[8] And
religion itself, in its reasonable forms, can take over the ether theory
as an article of faith, bringing into contradistinction the mobile cosmic
ether as creating divinity, and the inert heavy mass as material of
creation.[11] From this successfully scaled height of monistic knowledge
there open up before our joyously quickened spirit of research and
discovery new and surprising prospects, which promise to bring us still
nearer to the solution of the one great riddle of the world. What is the
relation of this light mobile cosmic ether to the heavy inert "mass," to
the ponderable matter which we chemically investigate, and which we can
only think of as constituted of atoms? Our modern analytical chemistry
remains for the present at a standstill, in presence of some seventy
irreducible elements, or so-called primary substances. But the reciprocal