pasture in which the chasm is situated, having lost cattle by falling into it, made the attempt to fill it up, and threw down many loads of stones without any visible effect, some of which were probably those which choked the aperture reached by Mr. Lloyd. The whole extent and actual depth of Eldon Hole have not therefore been ascertained.

There is a second kind of caverns which are essentially distinguished from the first by the circumstance that they reach the daylight at both ends, piercing through the rocks in which they are situated, and forming natural shafts. Their appearance is very remarkable when they occur on the top of isolated mountain-peaks, or of independent masses of rock; and when they are so straight that the day-light appears through them, they present a very remarkable aspect, and have been designated by the name of transparent caverns. On this account, the so-named Martin's hole is particularly celebrated. It penetrates the Tschingel-peak, one of the highest mountains of the Dodi chain; and twice in the year, in March and in September, the sun appears as if through a pipe, and gives to the valley beneath a highly singular and pleasing light. A similar phenomenon has been described by Pontoppidan as occurring in Norway, where there is a perforation of the mountain of Torghatten in Helgeland, of fifty fathoms in height, and a hundred fathoms in length, through which the daylight appears. Like phenomena present themselves at the hollow stone of Muggendorf; likewise in Saxon Switzerland, and a whole series of these perforations occur on the coast of the island of Heligoland, and on the coast of New Zealand.

The third and most frequent form of caverns is unquestionably that in which there is a series of extensions of nearly similar height and direction, which are connected with each other by passages of greater or less extent. This is the form of the caverns of the Hartz, the cave of Caripe visited by Humboldt, of Antiparos, and of the Peak of Derbyshire,

the entrance to which, with the castle on its summit, is here represented. This is also the form of the more important caves of Franconia. The extent of these penetrations into the mountains, in particular of such as are situated in limestone, is often very extraordinary. In many of them the extremity has never been reached; and it appears from concurrent testimony that some of them have been explored for more than a mile in length. In this respect, the cave of Adelsberg, six miles from Trieste, is mentioned. as the greatest of all, excelling all known caverns, not only in length, but in height. Deep abysses of five and six hundred feet often occur in it; and in one of these, it was found necessary to give up the attempt to proceed farther. The entrance resembles a fissure in a huge rock caused by an earthquake. Here torches are always lighted to conduct visiters. The cavity itself

seems as if divided into several large halls and other apartments. The vast number of pillars by which it is ornamented by nature gives it a superb appearance; for they are as white as snow, and have a kind of transparent lustre. The bottom is of the same material; so that a person may imagine he is walking among the ruins of some stately palace, amidst noble pillars and columns, partly mutilated and partly entire. From the top, sparry icicles are seen everywhere suspended; in some places resembling wax tapers, which, from their radiant whiteness, appear extremely beautiful. Here occurs that extraordinary animal the Proteus, in shape between a lizard and an eel, transparently white, with a tinge of rose colour about the head. It adds, as Davy remarks, one instance more to the number already known of the wonderful manner in which life is produced and perpetuated, even in places which seem the least suited to organised existences-an animal to whom the presence of light is not essential, living indifferently in air and in water, on the surface of the rock, or in the depths of the mud.

Of an analogous kind is the Peak cavern in Castleton Dale, the approach to which is in the highest degree magnificent. The traveller passes through a chasm between two ranges of perpendicular rocks, having on his left a rivulet which issues from the cave, and pursues its splashing course over craggy and broken masses of limestone. A vast mass of rock suddenly appears before him, with the mouth of the cavern, which assumes the form of a depressed arch, a hundred and twenty feet in width, forty-two in height, and about ninety in receding depth. At the first entrance, a spectator is surprised to find that a number of twine makers have established their residence and manufactory within this gulf; and their rude appearance and machines singularly combine with the sublime features of the natural scenery. After proceeding about thirty yards, the roof becomes lower, and a narrow passage is reached where the blaze of day, which has been gradually softened into twilight, wholly disappears, and all further researches must be prosecuted by torch-light. After penetrating twenty or thirty yards in a stooping posture, there is a spacious opening, beyond which is the margin of a small lake called the First Water, the over

hanging rock descending in one place to within twenty inches of its surface. The lake is crossed in a boat or skiff, partly filled with straw, in which the passenger lies down, and is conveyed to the other side, where a spacious vacuity opens 220 feet in length, 200 feet broad, and in some parts 120 feet high; but from the want of light, neither the roof nor the sides of this great cavity can be plainly discerned. Proceeding onwards by the side of the Second Water, there is a projecting pile of rocks popularly called Roger Rain's House, on account of the water incessantly dripping from the crevices of the roof. Beyond this, another hollow opens, called the Chancel, where the rocks appear much broken, and the sides are covered with stalactical incrustrations. Here the stranger is generally surprised by an invisible vocal concert, which bursts in wild and discordant tones from the upper regions of the cavern, where a group of women and children are stationed for the purpose, the inhabitants of some of the huts at the entrance. After leaving the Chancel, and passing the Devil's Cellar, and the Half-way House, the path leads beneath three natural arches to another vast concavity, termed Great Tom of Lincoln, from its resemblance to a bell. Here, under the influence of a strong light, the arrangements of the rock, the spiracles in the roof, and the flowing stream, produce a striking scene. From this point the vault gradually descends, the passage contracts, and at length leaves only room sufficient for the stream. The entire length of this great excavation is 2250 feet, and its depth from the surface of the mountain about 620. A striking effect is frequently produced by the explosion of a small quantity of powder, wedged into a crevice of the rock, the report of which rolls along the roof and sides like a heavy and prolonged peal of overwhelming thunder. On returning from this dark recess, the effect of the light is singularly impressive. The rocks appear as if highly illuminated, and the plants and mosses upon them so vividly green, as to produce the impression that the sun must be shining brilliantly upon them, when the day is really dull and hazy. The Peak cavern is thus an example of a succession of great chambers connected together by narrow passages; and when we remember the soluble nature of the stone, and the stream that flows through it, there can be no doubt that, if not formed altogether by the action of water, it yet owes its present condition to that agency. A more extraordinary spot, perhaps, is in the neighbourhood, at the foot of the Winnats, or Windgates, called also the "portals of the winds," a deep and narrow inclined chasm, about a mile in length, the lower descent of which commands a fine view of the beautiful vale of Castleton. Here is the Speedwell mine, an artificial excavation, leading to a great natural cavern. After descending upwards of a hundred steps, and reaching the blackness of darkness, the visitor embarks upon a canal so narrow as to be able to touch the rock on both sides, and the ceiling above. Proceeding along this channel, which is not far short of half a mile in length, the guide pushing along the boat, an immense vacuity in the mountain is reached, and landing upon a ledge of rock, the scene becomes indescribably strange and appalling with the aid of a Bengal light. On the one hand there is an abyss of unknown depth, appropriately called the Bottomless Pit, into which the water from the level falls with a startling sound, and which swallowed up forty thousand tons of material in the excavation of the mine. On the other hand an enormous cavity opens above, the ceiling of which no light can reach, for rockets have been here let off, and have given out their brilliant coruscations as freely as from the surface of the earth.

Humboldt describes a somewhat dissimilar but very remarkable cavern in the western world, in the province of New Andalusia, not far from the convent of Caripe, called the Cavern of the Guacharo-the name of a class of nocturnal birds who make it their abode. The exterior of the place was majestic even to one accustomed to the picturesque scenery of the Alps. He had visited the Peak Cavern, and was acquainted with the different caves

of Franconia, the Hartz and Carpathian mountains; and the uniformity generally observable in all these, led him to expect a scene of a similar character in that which he explored in the New World: but the reality far exceeded his expectations; for, if the structure of the cave resembled those he had elsewhere witnessed, the majesty of equinoctial vegetation gave an individual character and indescribable superiority to the entrance of the Cavern of the Guacharo. The entrance is a vaulted arch, eighty feet broad and seventy-two feet high; the steep rock that surmounts this opening is covered with gigantic trees, mixed with creeping and climbing plants and shrubs, brilliant with blossoms of the richest colours and the most varied forms. These form natural festoons, which hang from the mouth of the cave, and are gently agitated by the passing currents of air. Among them Humboldt enumerates a Dendrobium, an orchideous plant, with golden flowers spotted with black, and three inches long; a Bignonia, with a violet blossom; a purple Dolichos; and a magnificent Solandra, the deep orange flower of which has a fleshy tube four inches long. But this luxuriant vegetation was not alone confined to the exterior. The traveller, on following the banks of a subterranean stream into the grotto, beheld them, with astonishment, adorned for thirty or forty yards with the Praga palm tree, plantain-leaved heliconias, eighteen feet high, and arms that resembled trees in their size! It was not found necessary to light their torches till they had reached the distance of 430 feet, owing to the continuous direction of the cavern, which allows the light of day to penetrate thus far; and when this began to fail, the hoarse cries of the nocturnal birds began to be audible from a distance. The shrill discordant noise made by thousands of these birds, brought from the inmost recesses of the cave, and reverberated from the arched roofs, formed an indescribable clamour. The Indian guides, by fixing torches to the ends of long poles, showed the traveller the nests of the bird, which were constructed in funnel-shaped holes, with which the roof of the grotto was pierced in all directions, and generally at about sixty feet high. Still pursuing the course of the river, the cavern preserved the same width and height to the distance of 1458 feet from the mouth. The traveller, on turning round, was struck with the singularly beautiful appearance which a hill covered with the richest vegetation, immediately fronting the entrance of the grotto, presented. This, brilliantly illumined by the sun's rays, and seen through the vista of the dark cave, formed a striking contrast to the surrounding obscurity; while the large stalactites depending from the roof were relieved against the luminous back-ground of verdure. After surmounting, with some difficulty, an abrupt rise in the ground where the stream forms a small cascade, he found that the cave diminished in height to forty feet, but retained its original direction. Here a blackish mould was found, either brought by the rivulet, or washed down from the roof by the rain-water which penetrates the crevices of the rock; and in this he found seeds growing, which had been brought thus far by the birds, but so altered by the deprivation of light, that the species of plant, thus produced under such unfavourable circumstances, could not even be recognised. It was found impossible to persuade the Indian guides to advance further. The cries of the birds, rendered still more horrible by the contraction of the cave, had such an effect on their minds, that they absolutely refused to proceed; and, to the regret of Humboldt, he was compelled to retrace his steps.

Caverns, especially those which are situated in limestone, commonly present the formations called stalactites, from a Greek word signifying distillation or dropping. The manner of their production admits of a very plain and simple explanation. They proceed from water trickling through the roofs containing carbonate of lime, held in solution by carbonic acid. Upon exposure to the air the carbonic acid is gradually disengaged, and a pellicle of lime is deposited. The process proceeds, drop after drop, and, eventually, descending points hanging from the roof are formed, resembling icicles, which are com

posed of concentric rings of transparent pellicles of lime, presenting a very peculiar appearance, and, from their connection with each other, producing a variety of singular shapes. These descending points are the stalactites properly so called, from which the stalagmites are to be distinguished, which cover the floors of caverns with conical inequalities. These are produced by the evaporation of the larger drops which have fallen to the bottom, and are stalactites rising upwards from the ground. Frequently, in the course of ages, the ascending and descending points have been so increased as to meet together, forming natural columns, a series of which bears a striking resemblance to the pillars and arches of Gothic architecture.

The amount of this deposition which we find in caverns capable of producing it, is, in fact, enormous, and gives us an impressive idea of their extraordinary antiquity. The grotto of Antiparos-one of the islands of the Grecian Archipelago-is particularly celebrated on account of the size and diversity of form of these deposits. It extends nearly a thousand feet beneath the surface, in primitive limestone, and is accessible by a narrow entrance which is often very steeply inclined, but divided by level landing-places. After a series of descents, the traveller arrives at the Great Hall, as it is called, the sides and roof of which are covered with immense incrustations of calcareous matter. The purity

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of the surrounding stone, and the thickness of the roof in which the unfiltered water can deposit all impure admixtures, give to its stalactites a beautiful whiteness. Tall pillars stand in many places free, near each other, and single groups of stalagmites form figures so strongly resembling plants, that Tournefort endeavoured to prove from them a vegetable nature in stone. The remark of that intelligent traveller is an amusing example of over confidence: "Once again I repeat it, it is impossible this should be done by the droppings of water, as is pretended by those who go about to explain the formation of congelations in grottoes. It is much more probable that these other congelations we speak of, and which hang downwards or rise out different ways, were produced by our principle, namely, vegetation." The sight of the whole is described, by those who have visited this cavern, as highly imposing. In the middle of the Great Hall there is a remarkably large and fine stalagmite, more than twenty feet in diameter, and twenty-four feet high, termed the Altar, from the circumstance of the Marquis de Nointel, the ambassador from Louis XIV. to the Sultan, having caused high mass to be celebrated here in the year 1673. The ceremony was attended by five hundred persons; the place was illuminated by a hundred large wax torches; and four hundred lamps burned in the grotto, day and night, for the three days of the Christmas festival. This cavern was known to the ancient Greeks, but seems to have been completely lost sight of till the seventeenth century. Some of the caves of France and Germany have a high reputation for the number and beauty of their deposits; but the finest examples are found in the Cave of Adelsberg, to which reference has been made. The stalagmites here have formed two bridges over the subterranean river, which are situated almost a mile apart from each other, the inner one of which hangs suspended from eighty to a hundred fathoms over the abyss. An American visitor graphically describes some of the principal objects: -“We advanced with ease," he states, "through the windings of the cavern, which at times was so low as to oblige us to stoop, and at times so high that the roof was lost in the gloom. But every where the most wonderful varieties of stalactites and crystals met our admiring view. At one time we saw the guides lighting up some distant gallery far above our heads, which had all the appearance of verandahs adorned with Gothic tracery. At another, we came into what seemed the long-drawn aisles of a Gothic cathedral, brilliantly illuminated. The whimsical variety of forms surpasses all the powers of description. Here was a butcher's shop, which seemed to be hung with joints of meat; and there, a throne with a magnificent canopy. There was the appearance of a statue with a