Abstract
The outward velocity and acceleration through the solar corona of the disturbances responsible for the emission of 50 type III bursts recorded on the Dapto radio spectrograph are investigated by applying standard electron density models for the corona to the frequency drift of each burst. If current models for an active region are assumed, the velocities often remain unchanged from the lower corona out to heights of at least two solar radii above the photosphere. The mean velocity is about ie. Speeds of sources of type III bursts followed by type V continuum are similar to those for isolated type III bursts.