It has been 6 years since Mason et al. [ApJ, 647, L65-L68, 2006] drew attention to a remarkable
aspect of the behavior of energetic ions in some solar energetic particle (SEP) events. If the intensity
histories j(E,t) of ions of two species (O and Fe) were compared for two different values of
energy/nucleon (EO≠EFe) by normalizing their hour-averaged intensities near the maximum of the event,
their histories remained almost identical for more than a day.