And if above the earth was the kingdom of light, and purity, and holiness, what could be more plain, than that below it was the kingdom of darkness, and impurity, and sin? That was no theory to our forefathers: it was a physical fact. Had not even the heathens believed as much, and said so, by the mouth of the poet Virgil? He had declared that the mouth of Tartarus lay in Italy, hard by the volcanic lake Avernus; and after the unexpected eruption of Vesuvius in the first century, nothing seemed more clear than that Virgil was right; and that men were justified in talking of Tartarus, Styx, and Phlegethon as indisputable Christian entities. Etna, Stromboli, Hecla, were (according to this cosmogony) in like wise mouths of hell; and there were not wanting holy hermits, who had heard, from within those craters, shrieks, and clanking chains, and the howls of demons tormenting the souls of the endlessly lost. Our forefathers were not aware that, centuries before the Incarnation of our Lord, the Buddhist priests had held exactly the same theory of moral retribution; and that, painted on the walls of Buddhist temples, might be seen horrors identical with those which adorned the walls of many a Christian Church, in the days when men believed in this Tartarology as firmly as they now believe in the results of chemistry or of astronomy. And now--How is the earth shaken, and the heavens likewise, in that very sense in which the expression is used by him who wrote to the Hebrews? Our conceptions of them are shaken. How much of that mediaeval cosmogony do educated men believe, in the sense in which they believe that the three angles of a triangle are equal to two right angles, or that if they steal their neighbour's goods they commit a sin? The earth has been shaken for us, more and more violently, as the years have rolled on. It was shaken when Astronomy told us that the earth was not the centre of the universe, but a tiny planet revolving round a sun in a remote region thereof. It was shaken when Geology told us that the earth had endured for countless ages, during which continents had become oceans, and oceans continents, again and again. And even now, it is being shaken by researches into the antiquity of man, into the origin and permanence of species, which--let the result be what it will--must in the meanwhile shake for us theories and dogmas which have been undisputed for 1500 years. And with the rest of our cosmogony, that conception of a physical Tartarus below the earth has been shaken likewise, till good men have been fain to find a fresh place for it in the sun, or in a comet; or to patronize the probable, but as yet unproved theory of a central fire within the earth; not on any scientific grounds, but simply if by any means they can assign a region in space, wherein material torment can be inflicted on the spirits of the lost.