Popular Science Monthly/Volume 54/December 1898/Speleology, or Cave Exploration
|SPELEOLOGY, OR CAVE EXPLORATION.|
THE not very graceful word speleology was composed a few years ago by M. Émile Rivière out of Greek elements, as a translation of the German Höhlenkunde, to signify the study of caves. The study claims a place among the sciences, and is, I believe, able to justify its claim. Caves have been subjects of interest and curiosity in all times and countries. In the primitive ages, when palæolithic man was obliged to defend himself against the large Quaternary wild beasts, and did not yet know how to construct cabins, he lived in the most inaccessible caves, or those easiest to close, which he could find. Afterward, when man had advanced in civilization to the neolithic stage, and had somewhat improved tools and arms, having learned to build huts and villages, caves became simply burial places. In the historical periods of antiquity they were transformed into pagan sanctuaries or temporary hiding places in times of revolt, civil war, or invasion. Down to the middle ages and the renascence, they shared this function with abandoned quarries. Through these changes they gradually became objects of popular fear and absurd legend. I have nearly everywhere in France found legendary and profound belief in some monstrous basilisk or dragon in the depths of dark caverns, guarding immense treasures; and woe to the rash adventurer who tried to steal these riches!
In short, caves have suffered their vicissitudes; their use as habitations seems to be inversely proportioned to the degree of civilization. The miserable aborigines of Australia have not yet quite abandoned them; and in France the present occupation of the grottoes of Ezy, in the Eure, by some outcast families, who lead a sordid existence in them, indifferent to all social conventions, has recently been cited as an extremely curious anthropological phenomenon.
Science, too, has laid its hold on caves only within a little more than a century; for it was not till 1774 that Esper recognized that the large bones taken from the caverns near Baireuth, in Bavaria, were not those of human giants, but of extinct animals, and he called them, they being petrified by limestone, zoöliths, or animal-stones; and it was his remarks upon them that drew Cuvier's attention to paleontology.
Three sciences have of late years been advanced by the explorations of caves: paleontology; prehistory, or research among the remains of primitive men and their industries; and zoölogy, or the study of living beings. The animals of caverns—crustaceans, insects, batrachians, and fishes—constitute a special fauna, which has been for fifty years a subject of study to naturalists of various nations, and to the anatomy of which M. Armand Viré, of the Natural History Museum of Paris, has been giving special attention for five years past.
There are other sciences the study of which in connection with caves, while capable of yielding valuable fruits, has been too long neglected: geology, for their origin and formation; mineralogy, for their relations to metallic veins; meteorology, for thermometrical and barometrical variations and the formation of carbonic acid; terrestrial physics, for the experiments on gravity that might be carried on in deep vertical pits, supplementing the observations of Foucault in the Pantheon at Paris, and Airy in the English mines; hydrology, which has hardly yet perceived that caves are predominantly great laboratories of springs; agriculture, which might transform them into reservoirs for times of drought or storage basins in case of flood; and public hygiene, which is just beginning to discover that they may harbor in their fissures hitherto unsuspected causes of contamination of the water of the springs that issue from them. The number and importance of these new problems that have arisen from the recent extension of underground investigations seem fully to justify the specialization of the science of caves—another creation of the Speleological Society, now four years old. This special interest in the science of caves began about fifteen years ago, when, in 1883, three members of the Austro-German Alpine Club—Herren Harske, Marinitsch, and Müller—resumed in the limestone plateaus of Istria and Carniola called the Karst, explorations which had been actively and profitably carried on in the middle of the century, from 1850 to 1857, by Dr. Adolf Schmidt, whose discoveries in the caves of Adelsberg, Planina, and St. Canzion won him a membership in the Vienna Academy of Sciences. Their efforts and those of Herr F. Kraus, who died last year, had the result of interesting the Austrian Government in the subject; and since 1886 various engineers have been commissioned by the Minister of Agriculture to make official explorations and construct economical works in the caves and underground rivers of Istria, Carniola, and Herzegovina. Credits are granted every year for enterprises which prove to be more useful than would at first be thought.
It was at the same time, between 1883 and 1885, that I made my first investigation in the Causses of Lozère, Aveyron, and the adjoining departments of France, the results of which were to reveal for the first time to the public, and even to geographers, the picturesque beauties, then unknown, and now becoming the fashion, of the gorges of the Tarn, Jenta, and Dourbie, the rocks of Montpelier le Vieux, etc. In my excursions over the plateaus of the Causses I frequently met, at the level of the surface, open, dark holes, and mouths of vertical wells—avens—the depths of which no one had ever looked into, unsoundable, they said, which the peasants naturally took to be real mouths of hell. Recollecting what I had admired at Adelsberg and in various caves of the Pyrenees, I guessed these avens might also be doorways to subterranean splendors and scientific treasures. So I began in 1888 the methodical exploration of the unexamined natural cavities of my own land first, and then of other countries of Europe; and since then I have devoted several weeks every year to this work.
These pits are simply horizontal holes opening upon the surface of the ground, of very different forms and dimensions. Herdsmen are very careful not to let their cattle go too near them, for they sometimes fall in.
The diameter of these pits varies from a few inches to several hundred yards, and they are sometimes more than six hundred feet deep. It is not easy to go down into them, especially when they are on high levels away from habitations and roads. In such cases a considerable apparatus of ropes, rope ladders, telephone, portable boat, tent, etc., has to be taken along. The first measurement with the sounding line gives the depth only of the first pit—and there are often several succeeding one another. A rope ladder long enough to reach the bottom is then let down, and the man who descends has a rope tied about him for additional security, which is held by the people above. A great many pits are narrower at the top than lower down, forming something like a reversed speaking trumpet, so that the explorer finds it very difficult to make himself heard at the top; hence I have adopted the practice of taking a telephone along. The interior shapes of the pits are very diverse. The narrower ones are easiest to go down, because they permit one partly to support himself against their walls. The wider ones leave him hanging loose, in a position which he feels to be very precarious. When there is a second or third pit, and we have not ladders enough, we have to trust ourselves to a simple rope with a board fastened at the end of it for a seat. The gouffre of Vigne Close, in Ardèche, which is about six hundred feet deep, has five successive pits, and its complete exploration required three days. The bottom of the pit may be a simple cleft in the rock, or an immense cathedrallike chamber; as at Rabanel, near Ganges, and Hérault, the deepest abyss in France, the vault of which expands into a gigantic nave, five hundred feet high, which is lighted by the beam of light that falls through the opening, presenting a grand and indescribable spectacle. Some pits of less depth, as the Tin doul de la Vayssière, in Aveyron, and the Padirac well, in Lot, both leading to underground rivers, enjoy a still more complete illumination. Considerable talus banks close the ends of these broad pits, and are generally produced by the caving in of the roofs of caves.
Lively controversies and gross errors have prevailed concerning the geological formation of abysses. The abyss of Jean Nouveau, Vaucluse, among others, furnishes evidence against the false hypothesis that such pits are as a rule the results of cave-ins, whereas pits of that origin are rare and exceptional. These pits are for the most part fissures, the principal feature of which is their narrowness. At Jean Nouveau the greatest breadth is not more than about sixteen feet. It is the deepest vertical pit of a single shaft without intermediate terraces that we know of, and is about five hundred and thirty feet from the surface of the ground to its floor. The mass of stone rubbish at the bottom prevented our descending into a second pit.
Pits composed, like Vigne Close, of several successive wells, destroy another hypothesis—that of the formation of gouffres by the emissions from thermal springs.
The greatest danger in descending these pits arises from the showers of stones that sometimes come down upon the head of the explorer. These are often started by his friends the hunters, or by their dogs gamboling around at will.
While some of the caverns I have explored were stopped up by obstacles of one kind or another that prevented further progress, in others we found considerable rivers running a nearly free course. We rarely found pits formed by the collapse of the roofs of the cave in cases where the distance from the subterranean river which by its work of erosion provoked the catastrophe to the surface was more than one hundred metres. The pit of the Mas Raynal, Aveyron, is one hundred and six metres deep, and abuts upon a large subterranean river, which supplies the Sorgues of Saint-AfTrique, one of the finest springs of France. When we explored it, in 1889, we could not pass the low chambers which occur in it because the water was too high, and we have not visited it since. Its exploration in a dry season might reveal many very interesting chambers.
In the cave of Rabanel, the first well, which ends in a talus of fallen stones, furnishes an instance of a vertical fissure grafted, if we may use the word, upon an interior grotto that already existed. A stream runs through this grotto which falls into a second well twenty-six metres, and is then lost in smaller passages so nearly stopped up with earth that we were not able to follow it through its course of about a mile till it comes out at the Brissac spring.
The cave of Trebiciano, in Istria, near Trieste, the deepest known, has a total depth of more than a thousand feet. It is not, however, entirely natural, but is composed of numerous vertical fissures which lead, at about eight hundred and fifty feet below the surface, to a large cavern, at the bottom of which flows the subterranean river Recca. The fissures do not naturally communicate directly with one another, but the engineer Lindner was commissioned in 1840-'41 by the city of Trieste to construct for the municipality a supply of potable water from the underground streams, and after eleven months of labor made artificial connections between the different parts of the chasm.
These vertical pits are formed by the wearing down, from the top, by the waters which become ingulfed in them. This mode of their formation was demonstrated to me in 1895, when I was in Great Britain under a commission from the French Minister of Instruction. I then explored several caves in which the rivers were still running, and satisfied myself that the pits were simply absorbing wells. Such wells are not effective now in southern France and Austria, but in northern Europe, where rain is more abundant, they are still operative. I found the plainest evidence of this fact in Yorkshire, at the Gaping Ghyll, Ingleborough, where a river precipitates itself at one leap one hundred metres under the earth. English investigators and travelers had tried without success to descend into it in 1845, 1870, and 1894, having conquered only about one hundred and ninety-five feet of its total depth of two hundred and twenty-nine feet. It took me twenty-five minutes to go down upon a rope ladder which was suspended in the midst of the cascade. Fortunately, the pit had the daylight to the very bottom—a wonderful spectacle, compensating me for all my trouble and the long douche bath which greeted me at the end of the descent, where stretched an immense Roman nave nearly five hundred feet long, eighty feet wide, and ninety feet high, without any sustaining pillar. From the middle of the roof of this colossal cavern fell the cascade in a great nimbus of vapor and light—a wonderful fantastic scene, such as Gustave Doré or Jules Verne could never have imagined. The most pleasant feature of the whole of it, however, to me was the thought that I had succeeded where the English had failed, and on their own ground. The people were nevertheless very pleasant to me, and at my instance have continued the exploration and made some new discoveries.—Translated for the Popular Science Monthly from the Revue Scientifique.
- From an address before the Société des Amis des Sciences.