5 Conclusions

New broad-band linear polarization measurements have been obtained for a sample of 47 QSOs down to an accuracy of $\sim 0.2\%$. Most data are first-time measurements. The sample includes 27 BAL QSOs and 2 gravitational lens candidates (B1429-0053 and B2149-2745). With previous surveys by Hutsemékers et al. (1998) and Schmidt & Hines (1999), approximately 70 BAL QSOs have now measured polarization.

The present data show little contamination by interstellar polarization, and virtually any QSO with $p \geq 0.6\%$ is intrinsically polarized. Nine objects have $p \geq 1.0\%$, and one BAL QSO, B1333+2840, has $p = 5.9\%$. No polarization variability is detected, except, possibly, for the gravitational lens candidate B1429-0053.

Acknowledgements

It is a pleasure to thank Ingunn Burud for her participation in the September 99 observations, and Pierre Leisy for efficient support. This research is supported in part by contracts ARC 94/99-178 and PAI P4/05.