Studies of the magnetic white dwarfs GD 229 and Feige 7.

Summary. The possibility that the circular polarization of the magnetic degenerate star GD 229 might change, led us to obtain five spectra spanning 394 day. No significant changes in strength or location of the unidentified lines were detected. Higher-resolution spectroscopy suggests some fine structure in the X4l 85 feature. Even if the absorber is unknown we conclude that either its location is not affected by quadratic Zeeman effect, or the field is remarkably constant and homogeneous. Interpreted as Landau transitions in a field exceeding 200 MG the constancy of the field is even more remarkable. In Feige 7, which has resolved Zeeman components of both H and He I, we find good agreement with other observers and add some He I transitions whose Zeeman structure has not been predicted. In addition, there is a general depression, at N < 5000 A, which accompanies the relatively sharp ir and a+ transitions. We interpret this as arising from the o components or even from the m components in regions of larger field. Model atmospheres run 20 to 40 per cent above the continuum observed. We briefly discuss some related stars.