Having thus followed the exhalations of ocean to the end of what may be called the first stage of their journey, and seen them descend in a condensed form upon the surface of the dry land, I will now accompany them in their ulterior progress to the bosom of the seas. A great part of them have many transformations and changes to undergo ere they can accomplish their return; repeatedly rising in vapours from the solid earth, and falling in showers upon its surface; or circulating through the tissues of organic life: but after all these intermediate stages and delays, they ultimately find their way into rivulets or streams, which after many a meander restore them to the vast reservoir from which they arose. The waters that descend upon solid rocks, or fall in large quantities upon abrupt declivities, immediately flow into the brooks or rivers; but when they gently and gradually alight upon a porous soil, they are absorbed by the earth, and, displacing in virtue of capillary attraction, and of their superior weight, the air which fills the interstices between its solid particles, sink deeper and deeper until they meet with a solid and impenetrable stratum. If this forms a hollow basin, they naturally settle in the cavity; whence they are slowly displaced by fresh accessions and evaporation; but if its deepest declivity lies somewhere near the surface, they gradually gush forth under the form of sources or springs, having unequal distances to perform before they can reach the orifice. If no fresh supply of water falls, ere the most distant particles have reached their journey's end, the source dries up: but if new atmospheric precipitations continually take place, the source is perennial, although naturally of unequal strength at different times. The temperature of springs varies from icy coldness to boiling heat. Cold springs arise when the waters, by which they are fed, descend from high mountains or do not penetrate a great way into the bowels of the earth; but if the filtering waters reach a depth which is constantly of a higher temperature, they then gush forth in the form of warm or even boiling springs.