Top: the observed p_v% vs the interstellar E(B−V). The solid line represents the mean interstellar polarization (~3E(B−V)). E(B−V) values are not available for all ten objects. In all the panels the stars from the CH star catalogue are represented by solid triangles and the carbon stars from Hamburg/ESO survey by solid circles. The star represented by a solid square corresponds to HE 0519-2053. Bottom: the observed V-band percentage polarization (p_v%) vs the effective temperatures for the same objects as in Fig. 1. Polarization does not seem to have any correlation with temperature.