THE author discusses the experimental work done on the origin and transformations of actinium, and the various hypotheses which have been put forward as to the successive changes in the actinium series. He concludes that at some stages, besides α-and β-particles, particles of mass 3 and charge 2 are emitted. There is a detailed list of references, including some so recent as the year 1921.
Das Problem der Genesis des Actiniums.
Von. Sonderausgabe aus der Sammlung chemischer und chemisch-technischer Vorträge. Herausgegeben von Prof. Dr. W. Hertz. Band XXVI. Pp. iii + 64. (Stuttgart: Ferdinand Enke, 1921.) 5 marks.