One of the most remarkable and largest caverns known is that of Antiparos, a description of which is given by M. de Tournefort. We enter a rustic cavern about thirty feet broad, divided by some natural pillars; between two of which, on the right, the ground is on a gentle slope, and then becomes more steep to the bottom, about twenty feet; this is the passage to the grotto, or internal cavern, which is very dark, and cannot be entered without stooping and the assistance of torches. We then descend an horrible precipice by the assistance of a rope, fastened at the entrance, into another still more frightful, the borders of which are very slippery, with dark abysses on the left. By the assistance of a ladder we pass a perpendicular rock, and then continue to go through places somewhat less dangerous: but when we think ourselves in a safe path, we are stopped short by a tremendous obstruction, and are obliged to crawl on our hands and knees, or slide on our back, the length of a large rock, and then descend by a ladder. When we are at the bottom of the ladder, we still have to stumble over pieces of rocks for some time, and then we reach the celebrated grotto. It is computed to be three hundred fathoms deep from the surface of the earth, appears to be forty fathoms high by fifty broad. It is filled with large beautiful stalactites of various forms, as well from the roof of the vault as on the bottom.[AG]
[AG] See the Voyage de Levant, page 188, and also Remarks in a Journey from Paris to Constantinople, which contains a copious description of this astonishing phenomenon.
In part of Greece called Livadia (the Achaia of the ancients) there is a large cavern in a mountain which was formerly famous for the oracles of Trophonius; it is between the lake Livadia and the adjacent sea; at the nearest part it is about forty miles; and there are forty subterraneous passages across the rock, through which the waters flow.[AH]
[AH] See Gordon's Geography, 1733, page 179.
In all countries which produce sulphur, volcanos, and earthquakes, there are caverns. The ground of most of the Archipelago islands is cavernous; the islands of the Indian ocean, principally that of the Malacca's, appear to be supported by vaults and cavities. The land Azores, the Canaries, the islands of Cape de Verd, and in general almost every small island, is in many parts hollow and cavernous; because these islands are, as we have observed, only points of mountains where considerable ebullitions are made, either by the action of volcanos, of the water, of frosts, or other injuries of the weather. In the Cordeliers, where there are many volcanos, and where earthquakes are frequent, there are also a great number of caverns.
The famous labyrinth of the island of Candia, is not the work of nature alone; M. de Tournefort assures us that it has evidently been greatly enlarged by men; and most likely this cavern is not the only one which has been augmented by human labour. Every day mines and quarries are digging, and when abandoned for a long time, it is not easy to discover whether they have been the productions of nature, or formed by the hands of men. We know of quarries of considerable extent; for example that of Maestricht, where it is said 50,000 men may conceal themselves, and which is supported by upwards of 1000 pillars, twenty-four feet high, and the earth and rock above is more than twenty-five fathoms thick.[AI]
[AI] See Abridg. Phil. Trans. vol. XI. page 461.
The salt mines in Poland form still greater excavations than the above. There are generally vast quarries near large towns. But we cannot proceed farther in particulars; besides, the labour of man, however great, will ever hold but a small place in the history of nature.
Volcanos and waters which produce caverns internally, form also external clefts, precipices, and abysses. At Cajeta, in Italy, there is a mountain which had formerly been separated by an earthquake, in a manner so as to appear as if the division was made by the hands of men. We have already spoken of the divisions in the island of Machian, of the abyss of mount Azarat, of the gap in the Cordeliers, and that of Thermopyle, &c. To these may be added, the gap in the mountain of Troglodytes, in Arabia, which nature only sketched out, and which Victor Amadeus caused to be finished. Water as well as subterraneous fires produce considerable sinking of the earth, fall of rocks, and overthrow mountains, of which we can give many examples.
"In the month of June 1714, a part of the mountain of Diableret, in Valois, fell suddenly, and some time after, the sky being serene, it appeared to have taken a conical figure. Fifty-three huts belonging to the boors were destroyed, together with several people and a great many cattle, covering a square league with the ruins it occasioned. A profound darkness was caused by the dust; the heaps of stones thrown together were above thirty perches in height, stopped the currents of the water, and formed new and very deep lakes. In all this there was not the least trace of bitumen, sulphur, lime, nor consequently any subterraneous fire, and apparently the base of this great rock was perished and reduced to dust.[AJ]"