On the interpretation of the magnetic curves of the Ap stars as determined by the photographic technique.
Theoretical Zeeman-analyzed line profiles in magnetic stars have been computed for decentered dipole configurations of the magnetic field. It is found, on the basis of these profiles, that if the core of the lines are emphasized during the reduction of Zeeman-analyzed photographic plates, the longitudinal field obtained deviates from its true value. The deviations predicted are successful in producing the anharmonic variations observed in several Ap stars. Subject headings: line profiles - magnetic stars - peculiar A stars - Zeeman effect