The geological history of the Krakatoa volcano, especially the eruption of 1883, is amply described in the great work “Krakatau” by R. D. M. Verheer (1885), the Report of the Krakatoa Committee (Royal Soc. London 1888) and in the publications of B. G. Escher (Handel. 1e Nederl. Indisch Natuurwet enschapp. Congres 1919). In the last named the history of the Krakatoa-volcano is clearly shown in a block diagram series, which Professor Escher kindly permitted me to reproduce here as text figure 1. Before the famous Krakatoa-eruption of August 1883 took place, there were three islands: Lang-eiland (Long island), Verlaten-eiland (Deserted island) and Krakatau (Krakatoa).