and south of the equator is studied. In March to May of 1992, repeated sudden disappearances of the filaments
were noted. These sudden disappearances are dynamical rather than thermal in nature, because they are pre-
ceded by a great expansion of the filaments, which suggests their slow rise invariably heralding their rapid take-
off. The evolution of the filaments was accompanied by their rotation around the so-called pivot points near
their eastern ends. The northern and southern filaments rotated in opposite directions. We succeeded in record-
ing the last sudden disappearance—the takeoff on May 24 beyond the W limb of an eruptive prominence cor-
responding to the S filament—on a patrol film. The true height of the prominence was estimated to be of the
order of R
. The pattern of motions of five knots in the prominence was examined, and the time–velocity and height–velocity relations were derived.