Fig.1: Example of the semidurnal oscillations observed
on the flow rate of a sodastraw
( Grotte du Sourcier, Sainte Eulalie-enroyans, Drome) during summer 1970,
T (in s) is the mean time between two drops. T is then inversely proportional to the
flow rate. Stars indicate the strong perturbations induced by nearby thunderstorms,
which were dry at the cave location.