ABSTRACT
This chapter gives the results of a corresponding analysis of the long range α-particles from thorium C and an analysis of the groups of a-particles emitted from actinium C. In the present experiments, however, instead of recording the α-particles photo-graphically on a moving film; they have mainly employed the automatic method of counting, using thyratrons in place of the oscillograph. In interpreting the photographic records of the radium C experiment, it was necessary, to count only deflections of magnitudes lying between an upper and lower limit. The counting limits were measured electrically by the application of artificial potential surges of known magnitudes, so that it was possible to adjust the automatic recorder to count on the same basis as that normally used in analysing the photographic records of α-particles. In consequence of the emission of a β-particle from radium C, it is supposed that the resulting radium C nucleus is left in an excited state.
