ABSTRACT
This chapter includes early papers written in New Zealand, at the Cavendish Laboratory and during the Montreal period (1894-1906), as well as an introduction to Lord Rutherford's early work by Sir Edward Appleton, and some reminiscences of his time in Canada by Professors H. L. Bronson and Otto Hahn. In order to explain the presence of helium in radium on ordinary chemical lines, it has been suggested that radium is not a true element, but a molecular compound of helium with some substance known or unknown. On the theory that the radio-elements are undergoing atomic disintegration, the helium must be considered to be a constituent of the radium atom. The dis-integration takes place in successive stages, and at most of the stages a helium atom is projected with great velocity. If the particle is a helium atom, at least three particles must be expelled from uranium to reduce its atomic weight to that of radium.
