Part 1 of this dissertation describes a pressures apparatus for simultaneous measurement of the variation in the initial magnetic susceptibility and satu-rated isothermal remanence. The performance of the apparatus was checked using maghemite (y-Fe2O3)sample, of dimension 1 cm in diameter and 1.5cm in length, which may be heated up to 700C and subjected to pseudo-hydrostatic pressure up to 160MP a in an evacuated environment. The susceptibility of the sample is measured using a split-coil, which forms two arms of an ac inductance bridge operating at 703Hz. The noise level is 2 x 10-9m3, which is equivalent to the susceptibility of about 4mg of magnetic recording material such as acicular y-Fe2O3. Isothermal remanence of the sample is measured using apair of fluxgate probes that are aligned horizontal and connected in series opposition to combart environmental noise. The noise level is about 5 x 10-5A m2, equivalent to the saturation remanence of about 1mg of randomly oriented y-Fe2O3. For ease of data processing the magnetic susceptibility, remanence, temperature and pressure signals, obtained during an experimental, are acquired using a microcomputer. A magnetic technique, used to determine thatthe temperature of a confined sample, is described. results from preliminarystudies on the inversion of y-Fe2O3 are presented. Part 2 of this dissertation describes an automatic remanence hysteresis loop plotter. The design stresses on inexpensive and non-destructive method for quality control of magnetic tapes. Absolute measurement is not required. Quality is simply based on specifications of successful magnetic tapes. The relevant parameters are saturated remanent magnetic moment, m3r and remanent coercivity, Her. These are obtained from remanence hysteresis loop obtained using simple record and replay heads.