Comparison of the normalized total flux F_I (top; in this and in all similar figures the normalization is done at 7100 Å), the normalized polarized flux F_Q (we show thequantity −F_Q/max(|F_Q|) to facilitate the comparison with F_I), and the polarization P along a 90 deg inclination for the set of models differing in the value of V_blob. The radial optical depth of the blob decreases from 0.933 to 0.383, 0.098, and 0.029 as V_blob is increased from 2000, to 3000, 4000, and 5000 km s⁻¹ (the fractional blob velocity width is kept fixed). As discussed in the text, the polarization does not vary linearly with radial optical depth. Also apparent from the figure is the systematic increase in redshift of the polarized spectra with the increasing velocity of the blob. The blob opening angle is 20 deg in all four cases. The models have been smoothed with a Gaussian kernel (FWHM of 23.5 Å).