ium. I feel that we
are but beginning the list. And we know now that the atom, that once
we thought hard and impenetrable, and indivisible and final
and--lifeless--lifeless, is really a reservoir of immense energy. That
is the most wonderful thing about all this work. A little while ago
we thought of the atoms as we thought of bricks, as solid building
material, as substantial matter, as unit masses of lifeless stuff,
and behold! these bricks are boxes, treasure boxes, boxes full of the
intensest force. This little bottle contains about a pint of uranium
oxide; that is to say, about fourteen ounces of the element uranium. It
is worth about a pound. And in this bottle, ladies and gentlemen, in the
atoms in this bottle there slumbers at least as much energy as we could
get by burning a hundred and sixty tons of coal. If at a word, in one
instant I could suddenly release that energy here and now it would blow
us and everything about us to fragments; if I could turn it into the
machinery that lights this city, it could keep Edinburgh brightly lit
for a week. But at present no man knows, no man has an inkling of how
this little lump of stuff can be made to hasten the release of its
store. It does release it, as a burn trickles. Slowly the uranium
changes into radium, the radium changes into a gas called the radium
emanation, and that again to what we call radium A, and so the process
goes on, giving out energy at every stage, until at last we reach the
last stage of all, which is, so far as we can tell at present, lead. But
we cannot hasten it.'

'I take ye, man,' whispered the chuckle-headed lad, with his red hands
tightening like a vice upon his knee. 'I take ye, man. Go on! Oh, go
on!'

The professor went on after a little pause. 'Why is the change gradual?'
he asked. 'Why does only a minute fraction of the radium disintegrate
in any particular second? Why does it dole itself out so slowly and
so exactly? Why does not all the uranium change to radium and all
the radium change to the next lowest thing at once? Why this decay by
driblets; why not a decay en masse? . . . Suppose presently we find it
is possible to quicken that decay?'

The chuckle-headed lad nodded rapidly. The wonderful inevitable idea was
coming. He drew his knee up towards his chin and swayed in his seat with
excitement. 'Why not?' he echoed, 'why not?'

The professor lifted his forefinger.

'Given that knowledge,' he said, 'mark what we should be a