We propose to determine the field strength of a sample of
 magnetic cataclysmic variable stars in which the field strengths
 are expected to be in the range 2-10MG.
 Until now only 2 stars in this group have had their field
 strengths determined, (to within a factor of ~2).
 An accurate determination of the magnetic field strength of these
 systems is important in a number of ways:
 Firstly, recent high quality spectra obtained using ASCA has opened
 up a new era of observational astronomy in these objects.
 However, to model their spectra fully, an accurate determination of
 their magnetic field strength is necessary.
 Secondly, the accretion flow onto the white dwarf is influenced
 by the magnetic field. An accurate magnetic field
 strength is necessary to fully model the accretion flow.
 Thirdly, the magnetic field strength of the these objects is also
 needed to make progress in understanding the evolution of magnetic
 CVs - an area of particular contention at present.