"In one sense, and in one only, the idea of a continuous a order of things is admissible, in so far as the phenomena which introduced, and those which are to terminate, the existing dispensation, may have been, and may in future be, nothing more than a gigantic development of agencies which are in continual operation around us. The experience we possess of volcanic agency is not yet large enough to enable us to set limits to its force ; and as we see the rarity of subterraneous action generally proportioned to its violence, there may be appointed, in the natural order of things, convulsions to take place after certain epochs, on a scale which the human race has not yet lived long enough to witness. The soft silver cloud which writhes innocently on the crest of Vesuvius, rests there without intermission ; but the fury which lays cities in sepulchres of lava, bursts forth only after intervals of centuries; and the still fiercer indignation of the greater volcanoes, which make half the globe vibrate with earthquake, and shrivels up whole kingdoms with flame, is recorded only in dim distances of history: so that it is not irrational to admit that there may yet be powers dormant, not destroyed, beneath the apparently calm surface of the earth, whose date of rest is the endurance of the human race, and whose date of action must be that of its doom. But whether such colossal agencies are indeed in the existing order of things or not, still the effective truth, for us, is one and the same. The earth, as a tormented and trembling ball, may have rolled in space for myriads of ages before humanity was formed from its dust; and as a devastated ruin it may continue to roll, when all that dust shall again have been mingled with ashes that never were warmed by life, or polluted by sin. But for us the intelligible and substantial fact is that the earth has been brought, by forces we know not of, into a form fitted for our habitation: on that form a gradual, but destructive, change is continually taking place, and the course of that change points clearly to a period when it will no more be fitted for the dwelling-place of men" (John Ruskin, Of Mountain Beauty, XII.5).