O Tensorze Przepuszczalności
By means of geometrical interpretation of the tensor and making use of the geometrical properties of the terrain, it is shown that the necessary and sufficient condition for the permeability to be isotropic is that the tensor Pi should have the form (3). Analogous argument leads to the form (4) for a soil where the direction of gravity forces is treated as special. This form is symmetric if «mirror symmetry» of the soil is assumed. The paper contains also a section concerning the permoability of a layered soil.