This is due to the porosity of the soil in the former, and the very limited rainfall in the latter.
As a result of the porosity of the rock, many of the wells feel the influence of the sea and exhibit an ebb and flow.
For the growth of pot plants sand is an essential part of most composts, in order to give them the needful porosity to carry off all excess of moisture from the roots.
All those properties of soil known as texture, porosity, depth, inclination to the horizon, &c., are concerned here.
It is by no means an injudicious plan before laying out a system of water-meadows, which is intended to be at all extensive, to prepare a small trial plot, to aid in determining a number of questions relating to the nature and quantity of the water, the porosity of the soil, &c.
The anodes are made of retort-carbon or other chlorine-resisting material, and they are mounted in cells which serve as diaphragms. The material of these cells is usually cement, mixed with certain soluble salts which impart sufficient porosity to the material.
There is considerable distortion of the clay, resulting from combined shearing and tensile stress, above each of the steps of rock, and reaching its maximum at and above the highest rise ab, where it has proved sufficient to produce a dangerous line of weakness ac, the tension at a either causing actual rupture, or such increased porosity as to permit of percolation capable of keeping open the wound.