The Radioactivity ofMn56andI128

The purpose of this work was to examine the $\beta$-ray spectra of ${\mathrm{Mn}}^{56}$ and ${\mathrm{I}}^{128}$ as seen in the Wilson cloud chamber in an effort to correlate the measurements with the existing empirically regarded relations of the Fermi or the Konopinski-Uhlenbeck theory. A further study of the $\gamma$-rays which accompany these $\beta$-rays was made. In all measurements the difficulties of cloud-chamber technique were critically investigated. The results appear to fit the Fermi rather better than the K-U theory. However, the errors of cloud-chamber measurement are seen to be very serious in this type of work.