“As I drew near to the bottom of the cave, the bold balcony, on which I walked, expanded into a large sloping space, composed of thousands of broken vertical columns. The bottom was bounded by a compact range of pillars of an unequal height, and resembling the front of an organ.”
It is worthy of remark, that at the time when Mr. Troil visited the cave, the sea, by one of those uncommon chances which do not happen once in ten years, was so calm, that it permitted him to enter with a boat.
“At the very bottom of the cave, (says he,) and a little above the surface of the water, there is a kind of small cave, which sends forth a very agreeable noise every time that the water rushes into it.”—Letters on Iceland.
“As the sea was far from being completely still when I visited it, I heard a noise of a very different nature every time that the waves, in a rapid succession, broke against its bottom. This sound resembled that which is produced by striking a large hard body with great weight and force against another hard body in a subterraneous cavity. The shock was so violent, that it was heard at some distance, and the whole cavern seemed to shake with it. Being close to the place whence the sound issued, and where the water is not so deep, upon the retreat of the wave, I endeavoured to discover the cause of this terrible collision. I soon observed, that, a little below the basis which supported the organ-fronted colonnade, there was an aperture which formed the outlet of a hollow, or perhaps a small cave. It was impossible to penetrate into this cavity; but it may be presumed that the tremendous noise was occasioned by a broken rock, driven by the violent impetuosity of the surge against its sides. By the boiling motion of the water, however, in the same place, it is evident that there are several other small passages, through which it issues, after rushing into the principal aperture in a mass. It is therefore not impossible, when the sea is not sufficiently agitated to put the imprisoned rock in motion, that the air, strongly compressed by the weight of the water, which is in incessant fluctuation, should, on rushing out by the small lateral passages, produce a particularly strange sound. It might then be truly regarded as an organ created by the hand of nature; and this circumstance would fully explain why the ancient and real name of this cave, in the Erse language, is, The Melodious Cave.”
Sir Joseph Banks, in the description which he has given us of the cave of Staffa, says, that “between the angles a yellow stalagmitic matter has exuded, which seemed to define the angles precisely.” That is true; but the learned naturalist has not told us the nature of this yellowish matter.
Mr. Troil mentions it also: he says, that the “colour of the columns is a dark gray, but that the joints are filled with a quartzose stalactites, which distinctly marks the separation of the columns, and which, by the variety of its tints, has the most agreeable effect on the eye. On breaking off several pieces of it, which it is not very easy to do, owing to the height of the vault, I found that it was nothing but a calcareous matter, coloured by the decomposition of the iron of the lava, and intermixed with a little argillaceous earth. This stalactites has also very little adhesion, and is, in general, of an earthy nature. In several of the prisms I found some globules of zeolites, but in very small quantity. I also broke off from between two prisms, which were so apart as to admit of introducing my hand, an incrustation in which the white and transparent zeolites was formed into very perfect small cubical crystals, several of which were coloured red by the ferruginous lime arising from the decomposition of the lava. But I must repeat, that zeolites is very rare in this cave, and having myself broken off all the specimens that I was able to see, I doubt whether those who may visit the place after me will find any quantity of it.”
Dimensions of the Cave of Fingal.—Breadth of the entrance, taken at the mouth and at the level of the sea, thirty-five feet; height, from the level of the sea to the pitch of the arch, fifty-six feet; depth of the sea, opposite to the entrance, and twelve feet distant from it, at noon of the 27th of September, fifteen feet; thickness of the roof, measured from the pitch of the arch without to its highest part, twenty feet; interior length of the cave from the entrance to the extremity, one hundred and forty feet; height of the tallest columns on the right side of the entrance, forty-five feet; depth of the sea in the interior part of the cave, ten feet nine inches, in some places eight feet, and towards the bottom somewhat less.
Cave near Mexico.—A traveller of credit gives us an account, in the Philosophical Transactions, of a remarkable cave, some leagues to the north-west of Mexico, gilded all over with a sort of leaf-gold, which had deluded many Spaniards by its promising colour, but they could never reduce it into a body, either by quicksilver or fusion. This traveller went thither one morning with an Indian for his guide, and found its situation was pretty high, and in a place very proper for the generation of metals.
As he entered into it, the light of the candle soon discovered on all sides, but especially over his head, a glittering canopy of these mineral leaves, at which he greedily snatching, there fell down a great lump of sand, that not only put out his candle, but almost blinded him, and calling aloud to his Indian, who stood at the entrance of the cave, as being afraid of spirits and hobgoblins, it occasioned such thundering and redoubled echoes, that the poor fellow, imagining he had been wrestling with some infernal ghosts, soon quitted his station, and thereby left a free passage for some rays of light to enter, and serve him for a better guide. The traveller’s sight was somewhat affected by the corrosive acrimony of the mineral dust; but having relighted his candle, he proceeded in the cave, heaped together a quantity of the mineral mixed with sand, and scraped off from the surface of the earth some of the glittering leaves, none of which exceeded the breadth of a man’s nail, but with the least touch were divided into many lesser spangles, and with a little rubbing they left his hand gilded all over.
We must not neglect to notice The Nitre Caves of Missouri.—“On the banks of the Merrimack and the Gasconade are found numerous caves, which yield an earth impregnated largely with nitre, which is procured from it by lixiviation. On the head of Current’s river are also found several caves from which nitre is procured, the principal of which is Ashley’s cave, or Cave Creek, about eighty miles south-west of Potosi. This is one of those stupendous and extensive caverns, that cannot be viewed without exciting our wonder and astonishment, which is increased by beholding those complete works for the manufacture of nitre, situated in its interior.