while the land undergoes a continual change. Hills are insensibly mouldering away, valleys are ever being widened and deepened, rocky coasts and low alluvial shores suffer a constant abrasion, while even within the bowels of the earth the process of decomposition uninterruptedly proceeds. And thus, in place of remaining unchanged from the beginning, we know of nothing more mutable than the land on which we dwell, so that if the waste everywhere so apparent were to go on unchecked or unmodified, island and continent would eventually disappear beneath the waves. Here, however, another principle comes into operation. The debris removed from the land, as we have seen, is not annihilated. Slowly borne seawards, it settles down at river mouths or on the floor of the ocean as an ever-thickening deposit, which eventually hardens into rock, as solid and enduring as that whence it was derived. But it does not always remain there. Owing to the action of subterranean agencies with which we are but slightly acquainted, different parts of the sea-bottom are continually rising. Sometimes this process goes on very slowly, as along the shores of Sweden, where the coast has been ascertained to emerge in some localities at the rate of about thirty inches in a century; sometimes with prodigious rapidity, as on the coast of Chili, where the land was upheaved from two to seven feet in a single night. There can thus be no doubt that the mysterious agency which produces earthquakes and volcanoes on the land affects equally that portion of the earth's crust covered by the waters of the ocean, and must be ceaselessly employed in elevating large areas of sea-bottom into new continents, that will ere long become clothed with vegetation and peopled with animals. In contemplating, therefore, the constant decay in progress on the surface of the land, we see not a mere isolated process of waste, but a provision for future renovation. The sandstone cliffs of the shore are battered down and their debris carried out to sea, but when sea-bottom comes to be land-surface, they may be sandstone cliffs again, lashed once more by the breakers, and once more borne as sediment to the depths of the sea. And thus, in what may seem to us sublime antagonism, land is ever rising in the domain of ocean, and ocean ever encroaching on the regions of land. No sooner does a new island, or mountain peak, or wide area of continent, appear above the waves, than the abrading agencies are at work again. Rain, air, frost, rivers, currents, breakers, all begin anew the process of destruction, and cease not until the land has utterly disappeared, and its worn debris has sunk in mid-ocean to be in process of time once more dry land, and suffer another slow process of obliteration.