STALACTITE CAVERN AT AGGTELEK, HUNGARY: THE CAVE OF BORODLA.
CHAPTER XII.
ON CAVES IN GENERAL.
Their various Forms—Natural Tunnels—The Ventanillas of Gualgayoc—Eimeo—Torgatten—Hole in the Mürtschenstock—The Trebich Cave—Grotto of Antiparos—Vast Dimensions of the Cave of Adelsberg and of the Mammoth Cave—Discovery of Baumann’s Cave—Limestone Caves—Causes of their Excavation—Stalactites and Stalagmites—Their Origin—Variety of Forms—Marine Caves—Shetland—Fingal’s Cave—The Azure Cave—Cave under Bonifacio—Grotta di Nettuno, near Syracuse—The Bufador of Papa Luna—Volcanic Caves—The Fossa della Palomba—Caves of San Miguel—The Surtshellir.
The natural excavations which abound in many mountain chains, or on rocky shores washed by the stormy sea, are extremely various in their forms. Many are mere rents or crevices in the disruptured rocks; others wide vaults, not seldom of hall or dome-like dimensions, or long and narrow passages branching out in numerous ramifications. Not seldom the same cave alternately expands into spacious chambers, and then again contracts into narrow tunnels or galleries. The walls of many are smooth and nearly parallel; the sides of others are irregular and rugged. Many have narrow entrances and swell at greater depths into majestic proportions; while others open with wide portals, and gradually diminish in size as they penetrate into the rock. Sometimes an excavation pierces a mountain from side to side like a natural tunnel, so as to allow a passage to the light of day. Such, among others, are the numerous perforations or windows (ventanillas) in the serrated bastions of the rich silver mountain Gualgayoc in the Peruvian Andes, or the opening through one of the high peaks of the romantic island of Eimeo which rises within sight of Tahiti out of the dark blue ocean. According to a popular tradition, this hole owes its origin to Oro, the powerful god of war, who, having one day quarrelled with the minor god of Eimeo, hurled his mighty spear at him over the sea. As even gods, when losing their temper, are apt to miss their aim, the puny delinquent escaped unhurt, while the dreadful lance flew like a thunderbolt through the mountain, leaving the perforation as a lasting memorial of its passage. In Europe we likewise meet with several remarkable instances of such natural tunnels. One of the most celebrated is the grotto of Torgatten in Norway, which perforates a huge rock, 400 feet above the level of the sea. Its proportions are truly colossal, as it is no less than 900 feet long by from 80 to 100 feet broad; and the arches of its vast portals measure respectively 200 and 120 feet. Its floor is nearly horizontal, and covered with fine sand; its sides are smooth, as if they had been chiselled by the hand of man. The sea, with its numberless cliffs and white-crested breakers, appears through the immense gallery as through the tube of a gigantic telescope, and in fine sunny weather affords a spectacle of incomparable beauty.
Whoever has visited the romantic lake of Wallenstädt, in Switzerland, will have had his attention directed to a tunnel near the summit of the almost inaccessible Mürtschenstock, a favourite resort of the chamois. It is visible from the lake near the hamlet of Mühlehorn, and, though of considerable dimensions, appears to the eye like a mere speck of snow on the huge grey rockwall, which towers to a height of 7,517 feet. From the 1st to the 3rd of February, at 2 o’clock in the afternoon, the inhabitants of Mühlehorn see through this aperture the disk of the sun for the first time after a long winter.
In the structure of some caves a vertical direction predominates; as, for instance, in the Trebich Cave, three leagues from Trieste, which consists of several perpendicular shafts, connected by narrow transversal passages, and descending one after another, until finally, at a depth of more than a thousand feet, the cavern terminates in a wide vaulted space spanning a subterranean river. Such, also, is the renowned Grotto of Antiparos, into which the visitor is let down by a rope to a depth of about twenty fathoms. After reaching a tolerably even platform, he is obliged to descend another precipice, and then to proceed over slippery rocks until he finally reaches the terminal vault.
In most caverns, however, the chief direction is horizontal, either on several planes, separated from each other by more or less steep passages, or on a single level. The dimensions of caves are as various as their forms. Many are small and of inconsiderable depth—mere holes worn in the rock; while others are of a truly astonishing size, and fatigue the wondering spectator as he wanders through their lofty halls or endless galleries. The famous Cave of Adelsberg in Carniola has been explored to a distance of 1,243 fathoms from the chief entrance; and in the Mammoth Cave in Kentucky no less than 226 avenues branch out to the right and left from the main gallery, so as to form a network of subterranean passages and halls of various dimensions, whose total length has been computed at about 160 miles!
As many caves are without any visible communication with the external world, and the entrance of others is frequently narrow, and concealed behind rocks in solitary ravines on wild hill slopes or steep sea shores, far from the busy haunts of man, we cannot wonder that chance has frequently been instrumental in their discovery. Sometimes a hunter pursuing a wild animal has been led to the hidden cave in which it sought a refuge, or the workmen in a quarry have been suddenly surprised at meeting with a hollow in the rock, which opened an unexpected passage into the bowels of the mountain. The digging of wells, of cellars, of foundations, the boring for mines or Artesian wells, has often revealed the existence of unknown subterranean chambers; and so recently as 1868, one of the finest known caverns, which already attracts a number of delighted visitors, was discovered in the neighbourhood of the thriving manufacturing town of Iserlohn in Westphalia, on blasting a rock for the making of a railway. We may thus infer that a vast number of caves must still be totally unknown; many so situated that chance may one day lead to their discovery; while others are hollowed out at such vast depths in the earth-rind as to be for ever inaccessible to man.
Even of those caves which have been objects of curiosity for centuries, many have still been by no means thoroughly explored. In the year 1848 an American gentleman persuaded the guides of Baumann’s Cave in the Harz Mountains to accompany him on a voyage of discovery through parts of the cavern hitherto untrodden by man. It was no easy task to clamber over slippery rocks and deep chasms yawning into black abysses; but curiosity and the spirit of adventure kept leading them on from passage to passage and vault to vault, when suddenly the lights began to burn more dimly; and the glass of the guiding compass having been accidentally broken warned them to retrace their steps. They had been wandering for twenty-four hours in the subterranean labyrinth, and after so long an absence from the light of day, joyfully hailed the green hill slope which decks that mysterious palace of the gnomes. Franz Baumann, the first discoverer of the cavern, was less fortunate. Its tortuous windings confused the expert and intrepid miner, who lost his way in the recesses of the cave. While seeking in vain for an outlet, his sparing light went out. Three days he groped about in darkness, until at length, worn out and exhausted, he was led by a wonderful chance to the mouth of the cave. Before he died he had yet sufficient strength briefly to mention the wonders he had seen during his fatal expedition. His descendants still enjoy the privilege of serving as guides to the visitors of the cave, and never fail to relate the melancholy end of their ill-fated forefather.
Grottoes and caves occur in every kind of rock, in lavas, basalt, slate, and granite, as well as in limestone, dolomite, and gypsum; for the volcanic powers are capable of rending the hardest stone, and the foaming breakers of a turbulent ocean meet with no cliff that is able ultimately to resist their never-tiring assaults.