Line-profile variability in the Wolf-Rayet stars WR 135 and WR 111

We have obtained time-resolved observations of line-profile variations of t he two Wolf-Rayet stars WR 135 and WR 111. The spectra, taken during two co nsecutive nights, cover a broad range from 4470 to 6590 Angstrom. The profi le variability of the C III emission line at 5696 Angstrom in WR 135 is sho wn in detail. The principal difficulties to constrain the velocity law from the frequency drift of discrete spectral features is discussed, emphasizin g the crucial dependence on the adopted location of the line-emission regio n, and the possible necessity to distinguish between the motion of structur es and the ow of the matter. - Full access to the observational data is pro vided via anonymous file transfer.