ABSTRACT
This paper gives examples of the utility of the Greinacher method in counting α-particles under different conditions, and to describe a new method for analysing in detail the complexity of the α rays expelled from certain radioactive bodies. The results we have just described show the usefulness of the new methods-especially of the differential method-in investigating the complexity of α- ray groups. It appears that in the nuclei of radium C and and of thorium C and there must be a number of possible ray levels, some higher and some lower than the normal levels. It is probably significant that these bodies, radium C, thorium C and actinium C, which give complex α rays, are all of odd atomic number, with the exception of protoactinium, are of even atomic number. The large area of the counting chamber, comparatively weak sources of a-radiation like the long-range α particles from radium C and thorium C can be analysed.
