ght's interplay between worlds had to be conceived. The
existence of an all-pervasive medium called the luminiferous ether was
launched as a theory. Its reality has been so far demonstrated that
but very few doubters remain.

What facts of its conditions and powers can be known? It differs
almost totally from our conceptions of matter. Of the eighteen
necessary properties of matter perhaps only one, extension, can be
predicated of it. It is unlimited, all-pervasive; even where worlds
are non-attractive, does not accumulate about suns or other bodies; has
no structure, chemical relations, nor inertia; is not heatable, and is
not cognizable by any of our present senses. Does it not take us one
step toward an apprehension of the revealed condition of spirit?

Recall its actual activities. Two hundred and fifty-eight vibrations
of air per second produce on the ear the sensation we call _do_, or _C_
of the soprano scale; five hundred and sixteen give the upper _C_, or
an octave above. So the sound runs up in air till, above, say,
thirty-five thousand vibrations per second, there is plenty of sound
inaudible to our ears. But not inaudible to finer ears. To them the
morning stars sing together in mighty chorus:

"Forever singing as they shine,
'The hand that made us is divine.'"

Electricity has as great a variety of vibrations as sound. Since some
kinds of electricity do not readily pass through space devoid of air,
though light and heat do, it seems likely that some of the lower
intensities and slower vibrations of electricity are not in ether but
in air. Certainly some of the higher intensities are in ether.
Between two hundred and four hundred millions of millions of vibrations
of ether per second are the different sorts of heat. Between four
hundred and eight hundred vibrations are the different colors of light.
Beyond eight hundred vibrations there is plenty of light, invisible to
our eyes, known as chemical rays and probably the Roentgen rays.
Beyond these are there vibrations for thought-transference? Who
knoweth?

These familiar facts are called up to show the almost infinite
capacities and intensities of the ether. Matter is more forceful, as
it is less dense. Rock is solid, and has little force except obstinate
resistance. Steam is rarer and more forceful. Gases suddenly born of
dynamite touched by fire in the rock under a mountain have the
tremendous pressure of eighty thousand pounds to