The passage back of the White Throne is called the Serpentine Passage, and most of it is sufficiently high for traveling in an erect position; yet there are several places that require crawling. The first stopping point is the Gulf of Doom Room, or as it is also known, the Register Room, because here visitors usually write their names in the peculiar dark red clay, which is moist but firm and cuts with a polish. This room is twenty-five feet high and fifty feet wide, and looks off into the Gulf of Doom, which seems rightly named when a rock is thrown into it and you note the lapse of time before any sound returns; and when the awful Gulf is made visible by lights thrown in, one involuntarily seeks a firmer footing and clings to a projecting rock. The height of the Gulf is ninety-five feet and the distant sound of falling water is not reassuring. The walls are not smoothly worn away, but have the rough and weird appearance of having been torn by a torrent in a narrow mountain gorge, and are stained with the dark clay. Retracing our steps a short distance, if that style of locomotion could be called steps, we turned into Dore's Gallery, and surely that artist was in his usual working mood when he conceived this awful method of connecting the upper regions with the lower. Great bowlders have fallen down without helping to fill the black holes that received them, and into this real Inferno we proceeded to descend by narrow, ladder-like stairs provided with a light hand rail, and trembling slightly with the responsibility they assumed. If any one's courage trembled too, no notice was taken of it, and a record of exploring experiences does not necessarily include a confession of any doubts. On all the ladders in this Gallery was a fine white fungus growth in the form of a thick, heavy mold, that the lightest touch destroyed. In caves where some care is taken to protect this mold, it attains a growth of six or more feet and assumes the forms of sea-weed. Once down the first and longest flight of stairs, without any signs of a Dore dragon raising its huge body by heavy claws to a resting place among the rocks, awe divides more evenly with admiration; and being already well besmeared with mud, we climbed over the clay-covered bowlders and crawled through narrow holes with perfect satisfaction, enjoying each novel scene to the utmost.