  The Seyfert 1 galaxy NGC 3783 was intensely monitored between 1991 December
and 1992 August. We present the results from the ground-based observations in
the optical and near-IR, which complement the data-set from the IUE, discussed
elsewhere. Spectroscopic and photometric data from many observatories were
combined in order to obtain well sampled light curves of the continuum and of
H-Beta. During the campaign the source varied significantly. The light curves
of the optical continuum and of H-Beta are similar to those obtained with the
IUE. The near-IR flux did not vary significantly except for an increase at the
end of the campaign. The optical continuum and the flux of H-Beta lag the UV
continuum by 1 day or less and by 8 days respectively. These results confirm
that the continuum variations are simultaneous or have a very small lag across
the entire UV-optical range, and that the lines of NGC 3783 respond to ionizing
continuum variations with less delay than those of NGC 5548. As in NGC 5548,
the lag of H-Beta is greater than those of the high ionization lines.
