1941 Volume 23 Pages 142-159
γ-rays enitted from radioactive elements of Th and Ra series were investigated by the use of magnetie spectrometer. The relative intensities of several strong γ-rays whose existence was already confirmed by internal conversion β-rays were determined direetly. From these values and the absolute intensities of conversion β-rays the internal conversion coefficients were calculated and comparing them with the theoretical values obtained by Hulme et al the nature of radiations, whether dipple or quadripole, was deduced. In the case of Th series, improved level schemes for ThC and ThC' and ThD wire proposed in conneetion with β- and α- transformations