Great Britain abounds with caverns, and especially the county of Derby. Here there are no less than 28 of some celebrity, and some of lesser note. Several have already been alluded to in our notice of that county, as that stupendous recess, now converted from a rude and coarse appellation, to the Devil's Cave, or Peak Cavern, Elden Hole, and Pool's Hole, whence we shall restrict our observations to an abstract of Sir Richard Sullivans's ad venture in the Three Mile Cavern. This is an immense vacuity that has partly been effected by art, and which re ceives its name from its supposed extent. The descent is accomplished with much difficulty for 420 feet, and intro duces the spectator to two or three lofty caverns, beauti fully enamelled with spar. " Penetrating still farther," Sir Richard says, "we forced our way with infinite strug gles, through a narrow space between two rocks, and thence getting on our hands and knees, were, for the full distance of a mile, obliged to crawl, without ever daring to lift up our heads, the passage being both low and craggy ; and as it was likewise filled with mud, dirt, and a multi tude of bits of rock, our progress was painful indeed ; we still, however, hoped for something better. On we ac cordingly proceeded, till a dreadful noise rumbling along the horrible crevices of the cave, gave us to understand we were near a river. To this then we hurried; but des cription is inadequate to any thing like a representation of the scene ; a vast ocean seemed roaring in upon .us; in some places bursting with inconceivable impetuosity ; and at others falling through dreadful chasms, burst into shag gy forms to give it vent." It appears that this subter raucous stream is deep, and has a long course ; but whether it is absorbed in the earth, or finds a passage to the surface, is not explained. After having underwent many dangers and difficulties, not unattended with per sonal injury, the author concludes his narrative in these words : 44 Altogether, the depth we had descended was about 140 fathoms, or 980 feet, and the length about three miles, according to the miners' calculation. Neither at this distance were we at the end ; a passage still continued ; but so filled with water, and so full of peril, that the mi ners themselves were averse to further trial." Possibly the number and size of British grottos and caverns, ex ceed those within the same bounds of any other country with which we are acquainted ; nor are we aware that any spacious recess, (with the exception of the cave in Ken tucky,) opening directly from the earth, has been penetrat ed 2250 feet, as the Devil's Cave of Derbyshire.
In the limestone country of Virginia in North America, are several caverns of some extent, among which the most celebrated is Madison's cave, on the north side of the Blue Ridge. Its entrance is about two-thirds high in a mode rately elevated hill, into which it extends about 300 feet, branching out into subordinate caverns, sometimes ascen ding a little, but more generally descending, and at length terminates at different places in two basins of water of un known dimensions, that are never turbid. The vault of this cave is of solid limestone, from 20 to 40 or 50 Feet high, through which water perpetually percolates ; and trickling down its sides, has encrusted them with elegant drapery, or dripping from the top, generates conical stalactites both above and below.
Another cave, about 8 or 9 miles long, and with many branches, has lately been discovered in Kentucky. It is covered with stalactites : and a very remarkable mummy was found within it at a considerable distance from its mouth. See KENTUCKY, where we propose to give a full account of this interesting cavern.
Besides those curious excavations on the western coast of the Indian peninsula, some interesting rnvornc occur in that great range of mountains, which traversing Cochin China, penetrates the neighbouring countries. The inhabi tants retreat thither, or conceal their effects in them dur ing the time of war, and they are also kept concealed to avoid the expensive visits of the great men of the country. A naturalist, the late historian of these regions, affirms, would here find ample scope for observation : the caverns are full of petrifactions and crystallizations of various co lours: immense halls are formed, wherein may be seen the resemblance of altars or thrones; and quantities of fruits appear ready to drop from their trees. One most
remarkable grotto traverses a mountain throughout : its entrance and its exit being terminated by two fertile plains. The bottom is covered with water, which may be navigat ed by vessels ; and the roof, which is very lofty in some places, decreases elsewhere to 8 or 10 feet. There is ano ther in the same chain of mountains of vast extent, but abounding in deleterious exhalations ; and the water of a canal covering its bottom is dangerous to be drank. No one has hitherto ventured to explore its most distant ex tremities.
In various parts of Italy, we find several famous grottos, though less celebrated for their extent than from some other peculiarities ; and although known by the name of grottos, no crystallizations are seen in some of them. In Naples there is a spacious cavity, called Grotto dei Funaio li, or the Rope Makers' Grotto, because its entrance has long been devoted to this useful purpose. The roof exhi bits a rent, said to be the effects of lightning, and in other respects presents a menacing hut imposing asp,Ict, though the inhabitants carry on their operations in the most perfect confidence.
The grotto of Pausilippo near Naples, is a great excava tion, partly artificial, penetrating the mountain of that name 2316 feet. It is 89 feet high in the most lofty part, 24 where lowest, and about 22 in breadth, traversing vol canic tufa. The date of its formation is unknown ; but in modern times, Don John of Arragon, Viceroy of Naples, and Peter of Toledo, under Charles V. brought it to its present state, and now it serves for an ordinary', though disagreeable road from the city, with a glimmering light from two apertures above.
In the side of a hill, beside the lake Agnano, in Italy, there is an artificial excavation, unskilfully executed, call ed the Grotto del Cane. It is of limited dimensions, being only twelve feet deep, four broad, and nine in height at the entrance, but always decreasing as it recedes. The celebrity of this grotto, which had long been known, is owing to pestilential exhalations arising from the earth ; and it receives its name from the animal which is usually selected to demonstrate their presence. If a dog be brought within the sphere of the deleterious vapour, which remains within eighteen inches of the surface, its respiration im mediately becomes affected—the abdomen contracts—the eyes are fixed—and the tongue, now of a livid hue, hangs out during the first minute, while, in the next, the animal is totally deprived of motion. Death would inevitably fol low, but, on being speedily withdrawn, the lungs resume their play, and the creature gradually recovers its wonted strength and vigour ; nevertheless a severe shock is sus tained, as the same dog cannot support the experiment above twelve or fifteen times without destruction ; in which event it dies in convulsions. The Abbe Nollet, on stooping to inhale the vapour, felt as if he had swallowed boiling wa ter on the first inspiration, yet producing no painful sensa tions. On lowering his face, a kind of suffocation was ex perienced ; and probably, had the experiment been continu ed longer, dangerous consequences would have ensued. The vapour is whitish, and possesses some degree of heat. It never rises above eighteen inches from the earth ; and a torch immersed in it is extinguished, while the black smoke rolls over its surface without penetrating deeper. See Macleay, Description of the Spar. Cgve in Skye. Cat cott, Account of a Descent into Penpark Hole. Lloyd's Account of Elden Hole, Phil. Trans. vol. lxi. Leigh's His tory of Lancashire. Pilkington's View of Derbyshire. Farey's Survey of Derbyshire. Rudder's History of Gloucestershire. Hamilton, Canzpi, Phlagrei. Voyage Pittoresque d' Italie, torn. ii. Decouvertes des Savant Voyageurs, tom. i. p. 133. (c)