  A significant fraction of novae exhibit a series of rebrightenings on the
decline branch of their light curves. We use visual observations to study this
phase in several well-observed novae. We find that these rebrightenings are
isolated flare-like events on otherwise smooth light curves and we show that in
most novae in our sample the time intervals between consecutive flares
gradually increase as a geometric series; rebrightenings are equally spaced in
logarithmic time. We also find a correlation between the rate of increase in
the time between rebrightenings with the speed class of the nova in the sense
that slower novae tend to increase the time intervals faster. We attribute
these rebrightenings to instabilities in the envelope hydrogen burning and we
mention other cases of such timing pattern in astronomy and natural sciences in
general.
