Thanks for the Sansa Clip suggestion. It looks like I'll definitely have to buy a compatible device to listen to audible books because audible will not play on just any MP3 player. They're as protectionist and anti-competitive as Australian publishers.
No rock is completely impermeable, but some porous rocks like shale and pumice are mostly impermeable, because the pores are not interconnected, thus not allowing fluids or gases to pass through them. This is why shale makes a good cap-rock, and pumice floats instead of sinking.
pores. This facility is known as the permeability of the soil, and permeability is one of the more important soil proÂ¬ perties required in engineering studies involving soils. A general definition of permeability is that permeability is a measure of the ability of a porous medium to permit the flow of fluid through its pores.