Note 33 — Chapter IX · CATHODE RAYS AND RADIOACTIVE BODIES

Polonium has now been shown to be no new element, but one of the transformation products of radium. Radium itself is also thought to be derived in some manner, not yet ascertained, from uranium. The same is the case with actinium, which is said to come in the long run from uranium, but not so directly as does radium. All this is described in Professor Rutherford's Radioactive Transformations (London, 1906).—ED.