The A B C of atoms

by Bertrand Russell

-rays consist of particles, each of which is the nucleus of a helium atom;

-rays also consist of particles, but in this case they are electrons;

-rays do not consist of particles, but are of the nature of light-waves, only with a very much higher frequency, higher even (sometimes 20 times higher) than that of X-rays. We need not further consider the

-rays, which do not concern the transformations of the nucleus. It is the

-rays and