ule of any
degree of complexity is very great, and it is {72} by the breaking down
of complex molecules into simple ones that all our mechanical work is
done. And this is not all, for not only can the molecule be thus
broken in pieces, but the atom itself is capable of disintegration.
"Although we do not know how to break atoms up, they are liable every
now and then themselves to explode, and so resolve themselves into
simpler forms." "Atoms of matter are not the indestructible and
immutable things they were once thought."[3] The idea of the amount of
energy thus revealed as available for all kinds of active work is so
vast as to baffle calculation and even imagination. It has been said
that there is energy enough in fifteen grains of radium, if it could
all be set free at once, to blow the whole British Navy a mile high
into the air. The thought that we are thus encompassed on every side
by pent up potentialities of force, which if uncontrolled might at any
moment work our destruction, may well deepen in us the sense of the
need, not only for an originating, but for a continually directing mind
to superintend the conduct of the universe.

We have referred to more than one change of view to which the new
discoveries have led. We shall doubtless find that there are other
scientific theories {73} which will have ere long to be modified.
Already it is recognised that the arguments of Lord Kelvin (he was then
Sir William Thomson) and of Clerk Maxwell, which were based upon
calculations as to the "dissipation of energy," can scarcely remain
unaffected by what we now know, and suspect, of the crumbling and
re-forming of atoms.

And there are hints abroad of even more revolutionary suggestions. If
there has been one principle more imperatively and unanimously insisted
upon than another, it has been the uniformity of Nature's laws. What
then are we to make of a remark like the following, made by Professor
J. J. Thomson, perhaps only half-seriously, to the British Association
at Cambridge, in 1904? "There was one law," he said, "which he felt
convinced nobody who had worked on this question"--the radio-activity
of matter--"would ever suggest, and that was the constancy of Nature."

Not less startling is it to be told that a question may yet be raised
which will challenge "the conception of a luminiferous aether, which
for half a century has dominated physical science. It is possible," so
we are informed, "that the f