rrested by the
phenomena of a steadily burning flame, say that of a lamp. The
oil is sucked up into the wick and slowly decreases in volume.
At the point where the flame begins it rises in vapour, becomes
brilliant, and, in the case of a clear flame, disappears. There is
thus a constant movement from below upwards. The flame has
all the appearance of a "thing," with comparatively definite
form and continued existence, and yet is never really the same,
not for the minutest fraction of a moment. It is an appearance
born of incessant motion--let the motion stop, the flame is gone.
Where the burning is accompanied by smoke, there is an
apparent return of volatilised matter to solid form.

Now let a philosopher like Heracleitus be meditating on nature
as a circulatory system, and let him, by chance or otherwise,
bring together in his mind the phenomena of a burning lamp and
the cosmic facts for which he seeks an explanation--is it
difficult to imagine his Eureka? At any rate, Heracleitus felt that
in the phenomena of combustion he had gained an insight into
the ultimate constitution of nature. And he concluded from them
that there is no such thing as substance, properly so called, but
simply constant movement; the movement _is_ substance. The
great solid-seeming cosmos is motion; some of it visible, some
of it imperceptible; some of it rising upward to serve as fuel,
some of it falling downward, after having fed the flame, to form
the constituents of the present world. The motion is constant,
the stream ever-flowing: no "thing" is ever at rest, and, if it
were at rest, would disappear.

The marvel is that with such scanty data, Heracleitus was able
to attain to views which are in truly remarkable harmony with
the most advanced theories as to the constitution of matter.
Nowadays the very qualities of hardness and impenetrability are
being ascribed to motion--to the almost inconceivable rapidity
of the whirling of electrons within the system of the atom. Le
Bon, for example, in his "Evolution of Matter" and his
"Evolution of Forces," contends that atoms are continually
breaking down, radium presenting merely an extreme case of a
general rule, and that the final product is something which is
no longer matter. Robbed of motion, what we call matter
disappears! It eludes detection by any methods known to us, and
ceases, therefore, so far as we are concerned, to be existent.
Atoms, then, according to this modern doctrine, are