234 CHAP. XIII. On the Destruction of Rocks. If the interest of geological facts bears any proportion to their importance as they affect the condition of organized beings, there is none in the whole range of the science more calculated to attract attention than that which relates to the destruction of rocks, to the sure though tedious process by which they are con verted into earth and soil. On this process, depends the very existence of all the races of terrestrial vege tables and animals. In the smallest fragment that falls from the precipice, in the ceaseless flow of the torrent and the river, in the summer’s rain and the frosts of winter, the Geologist contemplates the agencies by which Nature renews and extends the animated surface of the earth; and, recurring to the commencement of these actions, beholds it a dreary waste of naked untenanted rock. Of the chemical Agents which tend to destroy Rocks. In enumerating the agents by which Nature operates her important purposes of demolition and destruction, if some shall appear insignificant in their power, or tedious in their effects, there are others, of which the results are rapid, important, and sensible to us where- ever we turn our eyes. Even the agency of those chemical causes which at first appears so feeble, is often highly efficacious in preparing the way for the