Across (or rather down) these unearthly waters, the guide can convey but four passengers at once. The lamps are fastened to the prow; the images of which, are reflected in the dismal pool. If you are impatient of delay, or eager for new adventures, you can leave your companions lingering about the shore, and cross the Styx by a dangerous bridge of precipices overhead. In order to do this, you must ascend a steep cliff, and enter a cave above, 300 yards long, from an egress of which, you find yourself on the bank of the river, eighty feet above its surface, commanding a view of those in the boat, and those waiting on the shore. Seen from this height, the lamps in the canoe glare like fiery eye-balls; and the passengers, sitting there so hushed and motionless, look like shadows. The scene is so strangely funereal and spectral, that it seems as if the Greeks must have witnessed it, before they imagined Charon conveying ghosts to the dim regions of Pluto. Your companions thus seen, do indeed-- "Skim along the dusky glades, Thin airy souls, and visionary shades." If you turn your eyes from the canoe to the parties of men and women whom you left waiting on the shore, you will see them by the gleam of their lamps, scattered in picturesque groups, looming out in bold relief from the dense darkness around them. Having passed the Styx, (much the smallest of the rivers,) you walk over a pile of large rocks, and are on the banks of Lethe; and looking back, you will see a line of men and women descending the high hill from the cave, which runs _over_ the river Styx. Here are two boats, and the parties, which have come by the two routes, _down_ the Styx or _over_ it, uniting, descend the Lethe about a quarter of a mile, the ceiling for the entire distance being very high--certainly not less than fifty feet. On landing, you enter a level and lofty hall, called the Great Walk, which stretches to the banks of the Echo, a distance of three or four hundred yards. The Echo is truly a river: it is wide and deep enough, at all times, to float the largest steamer. At the point of embarkation, the arch is very low, not more than three feet, in an ordinary stage of water, being left for a boat to pass through. Passengers, of course, are obliged to double up, and lie upon each others shoulders, in a most uncomfortable way, but their suffering is of short duration; in two boat lengths, they emerge to where the vault of the cave is lofty and wide. The boat in which we embarked was sufficiently large to carry twelve persons, and our voyage down the river was one of deep, indeed of most intense interest. The novelty, the grandeur, the magnificence of every thing around elicited unbounded admiration and wonder. All sense of danger, (had any been experienced before,) was lost in the solemn, quiet sublimity of the scene. The rippling of the water caused by the motion of our boat is heard afar off, beating under the low arches and in the cavities of the rocks.