idly with the carbon, giving out heat
and light and carbon dioxide, but why it does so admits of no
explanation. Herein again is where life differs from fire; we can
describe combustion in terms of chemistry, but after we have described
life in the same terms something--and this something is the main
thing--remains untouched.

The facts of radio-activity alone demonstrate the truth of the atomic
theory. The beta rays, or emanations from radium, penetrating one foot
of solid iron are very convincing. And this may go on for hundreds of
years without any appreciable diminution of size or weight of the
radio-active substance. "A gram of such substance," says Sir Oliver
Lodge, "might lose a few thousand of atoms a second, and yet we could
not detect the loss if we continued to weigh it for a century." The
volatile essences of organic bodies which we detect in odors and
flavors, are not potent like the radium emanations. We can confine them
and control them, but we cannot control the rays of radio-active matter
any more than we can confine a spirit. We can separate the three
different kinds of rays--the alpha, the beta, and the gamma--by magnetic
devices, but we cannot cork them up and isolate them, as we can musk and
the attar of roses.

And these emanations are taking place more or less continuously all
about us and we know it not. In fact, we are at all times subjected to a
molecular bombardment of which we never dream; minute projectiles,
indivisible points of matter, are shot out at us in the form of
electrons from glowing metals, from lighted candles, and from other
noiseless and unsuspected batteries at a speed of tens of thousands of
miles a second, and we are none the wiser for it. Indeed, if we could
see or feel or be made aware of it, in what a different world we should
find ourselves! How many million-or billion-fold our sense of sight and
touch would have to be increased to bring this about! We live in a world
of collisions, disruptions, and hurtling missiles of which our senses
give us not the slightest evidence, and it is well that they do not.
There is a tremendous activity in the air we breathe, in the water we
drink, in the food we eat, and in the soil we walk upon, which, if
magnified till our senses could take it in, would probably drive us mad.
It is in this interior world of molecular activity, this world of
electric vibrations and oscillations, that the many transformations of
energy take place. This