Movement of Water as Effected by Free Energy and Pressure Gradients: II. Experimental Analysis of Porous Systems in Which Free Energy and Pressure Gradients Act in Opposite Directions

Osmotic pressures across compacted clays were measured. These pressures were compared with pressures calculated from theory developed in the first paper of this series. Tortuosities and effective thicknesses of films in which water flows, which are necessary for these calculations, were calculated from hydraulic conductivity and salt diffusion data. The measured and calculated values of osmotic pressure were in fair agreement and probable reasons were given for the discrepancies observed. The qualitative agreement supports the assumptions and theory developed in paper I of this series.