are, as everybody knows, continually disintegrating,
discharging the enormous energy that is imprisoned in their molecules.
It may take generations, epochs, centuries, for them to get rid of it
and transform themselves into other substances, but they will inevitably
do so eventually. They're doing with more or less of a rush what all the
elements are doing at their leisure. A single ounce of uranium contains
about the same amount of energy that could be produced by the combustion
of ten tons of coal--but it won't let the energy go. Instead it holds on
to it, and the energy leaks slowly, almost imperceptibly, away, like
water from a big reservoir tapped only by a tiny pipe. 'Atomic energy'
Rutherford calls it. Every element, every substance, has its ready to be
touched off and put to use. The chap who can find out how to release
that energy all at once will revolutionize the civilized world. It will
be like the discovery that water could be turned into steam and made to
work for us--multiplied a million times. If, instead of that energy just
oozing away and the uranium disintegrating infinitesimally each year, it
could be exploded at a given moment you could drive an ocean liner with
a handful of it. You could make the old globe stagger round and turn
upside down! Mankind could just lay off and take a holiday. But _how_?"

Bennie enthusiastically waved his pipe at Thornton.

"How! That's the question. Everybody's known about the possibilities,
for Soddy wrote a book about it; but nobody's ever suggested where the
key could be found to unlock that treasure-house of energy. Some chap
made up a novel once and pretended it was done, but he didn't say _how_.
But"--and he lowered his voice passionately--"I'm working at it,
and--and--I've nearly--nearly got it."

Thornton, infected by his friend's excitement, leaned forward in his
chair.

"Yes--nearly. If only my transformers hadn't melted! You see I got the
idea from Savaroff, who noticed that the activity of radium and other
elements wasn't constant, but varied with the degree of solar activity,
reaching its maximum at the periods when the sun spots were most
numerous. In other words, he's shown that the breakdown of the atoms of
radium and the other radioactive elements isn't spontaneous, as Soddy
and others had thought, but is due to the action of certain extremely
penetrating rays given out by the sun. These particular rays are the
result of the enormous temperature of