at last it has been exploded, and instead of the atom being primary
and indivisible we find it a very complex affair, a kind of miniature
solar system, the centre of a varied attraction of molecules, corpuscles
and electrons. Had we held to the atomic theory and denied smaller
sub-divisions of matter there would be no accounting for the emissions
of radium, for as science now believes these emissions are merely the
expulsion of millions of electrons.

Radium gives off three distinct types of rays named after the first
three letters of the Greek alphabet--Alpha, Beta, Gamma--besides a
gas emanation as does thorium which is a powerfully radio-active
substance. The Alpha rays constitute ninety-nine per cent, of all the
rays and consist of positively electrified particles. Under the
influence of magnetism they can be deflected. They have little
penetrative power and are readily absorbed in passing through a sheet
of paper or through a few inches of air.

The Beta rays consist of negatively charged particles or corpuscles
approximately one thousandth the size of those constituting the Alpha
rays. They resemble cathode rays produced by an electrical discharge
inside of a highly exhausted vacuum tube but work at a much higher
velocity; they can be readily deflected by a magnet, they discharge
electrified bodies, affect photographic plates, stimulate strongly
phosphorescent bodies and are of high penetrative power.

The radiations are a million times more powerful than those of uranium.
They have many curious properties.

If a photographic plate is placed in the vicinity of radium it is
almost instantly affected if no screen intercepts the rays; with a