The number of β-particles from Radium E

Using an electrical counter, the number of α- and β-particles from a source of Radium D, Radium E and Radium F in equilibrium has been measured: it has been found that after correction for reflection at the source, their numbers were about equal. According to previous work on their absorption, the β-particles from Radium D would not be recorded under the conditions of these experiments. On this assumption the observed β-radiation was due to disintegration of Radium E, and since this was in equilibrium with Radium F, it follows that about one β-particle is emitted per disintegrating atom of Radium E.