To determine the magnetic susceptibility and the magnetization at saturation point, we used a quick method that it based on Gouy’s relation and leads to good results in the case of magnetic fluids with small susceptibility. It is studied the way magnetic fluids with different densities behave in magnetic field, at different intensities of the field. It is measured the magnetic susceptibility and the magnetization MS at saturation point for three cylindrical probes suspended in a magnetic field perpendicular to the probes. The results obtained in Timişoara are very close to those obtained using Gouy’s method. As a conclusion, one can say that Gouy’s method is a simple, correct and very efficient method.