  We conducted a spectropolarimetic survey of 58 high proper-motion white
dwarfs which achieved uncertainties of >2 kG in the Halpha line and >5 kG in
the upper Balmer line series. The survey aimed at detecting low magnetic fields
(< 100 kG) and helped identify the new magnetic white dwarfs NLTT 2219, with a
longitudinal field B_l = -97 kG, and NLTT 10480 (B_l=-212 kG). Also, we report
the possible identification of a very low-field white dwarf with B_l = -4.6 kG.
The observations show that ~5% of white dwarfs harbour low fields (~10 to ~10^2
kG) and that increased survey sensitivity may help uncover several new magnetic
white dwarfs with fields below ~1 kG. A series of observations of the high
field white dwarf NLTT 12758 revealed changes in polarity occurring within an
hour possibly associated to an inclined, fast rotating dipole. Also, the
relative strength of the pi and sigma components in NLTT 12758 possibly
revealed the effect of a field concentration ("spot"), or, most likely, the
presence of a non-magnetic white dwarf companion. Similar observations of NLTT
13015 also showed possible polarity variations, but without a clear indication
of the timescale. The survey data also proved useful in constraining the
chemical composition, age and kinematics of a sample of cool white dwarfs as
well as in constraining the incidence of double degenerates.
