shown by the undulatory theory of light. Light is not a substance but is
the effect produced on the eye by the impinging of the ripples of the ether
upon the retina. These waves are excessively minute, ranging in length from
1-39,000th of an inch at the red end of the spectrum to 1-57,000th at the
violet end. Next remember that these waves are not composed of advancing
particles of the medium but pass onwards by the push which each particle in
the line of motion gives to the particle next to it, and then you will see
that if there were a break of one fifty-thousandth part of an inch in the
connecting ether between our eye and any source of light we could not
receive light from that source, for there would be nothing to continue the
wave-motion across the gap. Consequently as soon as we see light from any
source however distant, we know that there must be a continuous body of
ether between us and it. Now astronomy shows us that we receive light from
heavenly bodies so distant that, though it travels with the incredible
speed of 186,000 miles per second, it takes more than two thousand years to
reach us from some of them; and as such stars are in all quarters of the
heavens we can only come to the conclusion that the primary substance or
ether must be universally present.

This means that the raw material for the formation of solar systems is
universally distributed throughout space; yet though we find that millions
of suns stud the heavens, we also find vast interstellar spaces which show
no sign of cosmic activity. Then something has been at work to start cosmic
activity in certain areas while passing over others in which the raw
material is equally available. What is this something? At first we might be
inclined to attribute the development of cosmic energy to the etheric
particles themselves, but a little consideration will show us that this is
mathematically impossible in a medium which is equally distributed
throughout space, for all its particles are in equilibrium and so no one
particle possesses _per se_ a greater power of originating motion than any