Thus when Coleridge's imagination was set free, the mode of feeling declared itself which had persisted down the ages to the present. The primitive experience is there in its essentials, enriched by the aesthetic and intellectual gains of the intervening centuries. Doubtless there is a living idea, or rather a group of living ideas, behind the phenomena of subterranean waters. Wordsworth has described a more personal experience which chimes in with all that has been said. "Through a rift Not distant from the shore on which we stood, A fixed, abysmal, gloomy, breathing place-- Mounted the roar of waters, torrents, streams Innumerable, roaring with one voice! Heard over earth and sea, and, in that hour, For so it seemed, felt by the starry heavens." If the modern poet could be thus affected, how much more the primitive man who looked down on water falling into chasms, or rushing through their depths. It was natural that such experiences should find expression in his systems of mythology. The general form they assume is that of springs and rivers in the underworld, the best known of which appear in the Graeco-Roman conceptions of Hades. Homer makes Circe direct Odysseus thus. He is to beach his ship by deep-eddying Oceanus, in the gloomy Cimmerian land. "But go thyself to the dank house of Hades. Thereby into Acheron flow Pyriphlegethon and Cocytus, a branch of the water of the Styx, and there is a rock and the meeting of the two roaring waters." Such were the materials which, with many additions and modifications, developed into the Hades of Virgil's sixth AEneid, with its lakes, and swamps and dismal streams. The subterranean waters figured also in the Greek mysteries, and are elaborated with much detail in Plato's great Phaedo Myth--in all these cases with increasing fullness of mystical meaning. In the popular mind they were incrusted with layers of incongruous notions and crude superstitions. But, as Plato, for one, so clearly saw, there is always at their core a group of intuitions which have their bearing on the deepest problems of human life, and are capable of moulding spiritual concepts.