1 Introduction

This paper is one of a series given by the authors, describing the magnetic field structure in magnetic CP stars and its relation to the surface distribution of the chemical elements. The existence of such a relation was suspected and verified in the papers by Michaud (1970), Glagolevskij (1994), Hatzes (1997) and other authors. The longitudinal effective magnetic field $B_{\rm e}$ was measured photoelectrically from the hydrogen lines by Borra & Landstreet (1980). The distribution of He and Si over the surface was studied by Goncharskij et al. (1983), Hiesberger et al. (1995), Hatzes (1997), and Kuschnig et al. (1999). Despite this task had already been performed formerly, we repeated it by applying our new method of "magnetic charge distribution" (Gerth et al. 1997, 1998, 1999, 2000), which offers new possibilities of modelling the magnetic field structure.