  We have detected longitudinal magnetic fields between 2 and 4kG in three
normal DA white dwarfs (WD0446-790, WD1105-048, WD2359$-$434) out of a sample
of 12 by using optical spectropolarimetry done with the VLT Antu 8 m telescope
equipped with FORS1. With the exception of 40 Eri B (4kG) these are the first
positive detections of magnetic fields in white dwarfs below 30kG. A detection
rate of 25% (3/12) may indicate now for the firsttime that a substantial
fraction of white dwarfs have a weak magnetic field.This result, if confirmed
by future observations, would form a cornerston for our understanding of the
evolution of stellar magnetic fields.
