freely from one atom to another, in copper, it is calculated, the
electron combines with an atom and is liberated again a hundred
million times a second. Even chemical action enters the sphere of
explanation.

However these hypotheses may fare, the electron is a fact, and
the atom is very probably a more or less stable cluster of
electrons. But when we go further, and attempt to trace the
evolution of the electron out of ether, we enter a region of pure
theory. Some of the experts conceive the electron as a minute
whirlpool or vortex in the ocean of ether; some hold that it is a
centre of strain in ether; some regard ether as a densely packed
mass of infinitely small grains, and think that the positive and
negative corpuscles, as they seem to us, are tiny areas in which
the granules are unequally distributed. Each theory has its
difficulties. We do not know the origin of the electron, because
we do not know the nature of ether. To some it is an elastic
solid, quivering in waves at every movement of the particles; to
others it is a continuous fluid, every cubic millimetre of which
possesses "an energy equivalent to the output of a
million-horse-power station for 40.000,000 years" (Lodge); to
others it is a close-packed granular mass with a pressure of
10,000 tons per square centimetre. We must wait. It is little
over ten years since the vaults were opened and physicists began
to peer into the sub-material world. The lower, perhaps lowest,
depth is reserved for another generation.

But it may be said that the research of the last ten years has
given us a glimpse of the foundations of the universe. Every
theory of the electron assumes it to be some sort of nodule or