The rivulet, by the side of which we walked to the Fantastical Tree, receives several streams as it flows along; and, as if it left with regret so beautiful a residence, after forming a thousand serpentine windings in the meadow, it glides gently towards its mouth. In that place, a hole, formed by an opening of the earth, receives and transmits it through subterraneous channels. We came to the place where it was broadest. The bottom was of smooth gravel, and the water not above an inch deep. The Prefect went in and I followed him. I had gone but a few paces, when the bottom gave way: I sunk, but it was only to my waste; and I remained in that posture, without being able to get to one side or the other. Fear nothing, says the Prefect, calmly enjoy the last spectacle I have reserved for thee. I then gave myself up to the efforts of the waters, which carried me away, and I soon entered into the subterraneous cavities, where they were lost. At a little distance, the rivulet flowed into another, and soon after, both ran into a river. I was carried from stream to stream; I crossed gulphs, lakes, and seas. As long as a faint light permitted, I contemplated the internal frame of the earth. It is a labyrinth of immense caverns, deep grottos, irregular crevices, which have a communication with one another. The waters that flow in these subterranean places, spread themselves sometimes into vast basons, and seem to stagnate; sometimes they run with a rapid stream through narrow straits; and dash against the rocks with such impetuosity, as to produce the phosporus and flashes of lightening; very often they fall from the top of the vaults with a dreadful noise. The dazzled eye sees, as it imagines, the foundations of the earth shake; one would think, that the whole was turned upside down, and falling into chaos. When the glimmering light, which I had enjoyed some time, came to fail, I found myself buried in profound darkness, which increased the horror, I had conceived at what I had seen. A hideous noise, mixed with the murmuring of the streams, with the whistling of the gulfs, with the roaring of the torrents, threw me into great perturbation of mind; and my troubled fancy formed to itself a thousand frightful images. I went on a good while in this darkness; and I know not how far I had gone when a faint light struck my eyes. It was not like that which precedes sun-rising, or follows sun-set; but that melancholy light, which a town on fire spreads at a distance in the shade of the night. I was some time before I saw whence it came: At last, I found myself close to the most terrible of all the sights.