In connection with the recent researches of Mr. K. Takahasi* and Mr. S. Watanabe* the now already classical works of Mr. T. Kameda and Prof T. Terada on the apparent periodicity observed in statistical series have again been taken in argument and extended so as to include the not necessarily independent series, whereby, however, we have been obliged to set a definite assumption as to the distribution function, namely to be that of Gauss' normal law. When very strong correlations between successive events are assumed, the, “apparent” periodicity will pass into the “real” periodicity, under which we understand, not the fixed, usual periodicity of definite phase and amplitude, but the dynamical periodicity of the equation of motion, which can possibly be supposed to govern the phenomenon considered. The general discussion of the minimum-minimum curve of Mr. Takahasi is accompanied by serious mathematical difficulties and complications and touched only in a case, which allows the simple mathematical treatment.
