selves on a back-ground of verdure, beyond the opening of the cavern. This is far, however, from being its whole extent, which appears never to have been fully explored, Indian superstition recoiling from the attempt to penetrate further, besides natural difficulties lying in the way.

The guacharo, of which this cavern is one of the chosen haunts, is a bird unknown apart from the mountains of Caraccas, about the size of a domestic fowl, of a dark bluish-grey plumage. Light is painful to it, and hence here the bird nestles in the day-time, issuing from its dark abode at night-fall in search of food, being one of the few examples that occur of a nocturnal bird, unlike our owls, feeding on fruits and seeds. Thousands of them, disturbed and frightened by the torches, when the cavern is visited, fill it with their wild cries, drowning every other noise, and add indescribably to the effect produced by the gloom of the place. Far in the interior, seeds carried by the guacharoes to feed their young, and accidentally dropped,. have germinated in the mould which the stream has deposited upon the calcareous incrustations. These traces of organization amid darkness, consisting of pale blanched stalks, several feet in height, with half-formed leaves, are gazed

upon by the Indians with wonder and fear, as phantoms banished from the face of the earth. It is their common superstition, that the souls of their ancestors sojourn in the deep recesses of this cave; and hence to die and join their fathers, and to go to the guacharoes, are synonymous expressions. To them "life and immortality" have not been "brought to light by the gospel," after years of connexion with the Spanish padres in the neighbouring convent of Caripe, who exact from the native race a tribute of guacharo-oil to keep the church lamp trimmed. The conduct pursued towards their forefathers by the European conquerors-ostensibly the missionaries of the cross, but the veriest slaves of mammon-was little calculated to conciliate the native races towards that corrupted form of Christianity presented to their attention; and their thinned and miserable descendants, often smarting under the same injurious dealing, may well cling to the idea of finding a resting-place in the future, apart from the white man's presence. Alas! how incalculably has the truth been crippled in its influence, and injured in its fair fame, by the alien spirit and conduct of nominal adherents to it!

CHAPTER VI.

ICE, MEPHITIC, AND OSSEOUS CAVERNS.

Accident to the emperor Tiberius-Summer-produced ice-caves -At Szelitze in Hungary-In Russia-Sir R. T. MurchisonIce caves in France-Explanation-Mephitic caverns-Grotto del Cane-Carbonic acid gas-Accidents-Crater at NeyrucDunsthole near Pyrmont-Poisoned valley of Java-DarwinFoersch-False statements of the Upas-Account of the treeAccount of the valley-Osseous caves-Wirksworth-Kirkdale -Hyæna den-German bone caves-Bauman's Höhle-Zahnloch-Gailenreuth-Kühloch-Estimate by Dr. BucklandInferences-Moral lessons.

TACITUS relates of the Roman emperor Tiberius, that, retiring to one of his country seats, called the Caverns, (Spelunca,) near Fundi, and contiguous to some natural cavities after which it was named, he was dining in one of them, for the sake of the coolness it afforded, when an accident occurred, which had well-nigh proved fatal to him. The roof suddenly gave way, and buried several of his attendants beneath its ruins, when Sejanus threw himself over the emperor to protect him with his own body, and was found in that position by the soldiers who The wealthy Romans were

came to his relief.

of the day begins to abate, and the nights grow cold, the ice begins to dissolve, and is quite cleared away by the arrival of Christmas, when the cavern is perfectly dry, has an agreeable temperature, and is the haunt of swarms of flies, gnats, bats, owls, hares, and foxes; resorting to it as a winter retreat, till the spring returns.

When travelling in Russia, sir Roderick Murchison met with a cavern of a similar description, near the imperial salt-works, at Iletski, on the south of the Ural mountains, where a series of natural hollows occur in a mass of gypsum, which the peasantry employ as storehouses. It was then summer, and the weather was exceedingly hot, but, at a short distance within the door, and on a level with the village street, beer and quash were found half frozen. Further on, solid undripping ice hung from the roof and sides, and the floor was a mass of hard · snow, ice, or frozen earth. But, during the winter-part of the year, when the weather is more rigorous, and the entire country without is frost-bound, this cavern, of which there are several similar to it in the district, is not only free from ice, but has so mild a temperature, that the Russian peasants affirm, they should not mind sleeping in it without their sheep

skins. แ Standing on the heated ground," sir Roderick remarks, ""and under a broiling sun, I shall never forget my astonishment, when the man to whom the cavern belonged unlocked a frail door, and a volume of air, so piercingly keen, struck the legs and feet, that we were glad to rush into the cold bath in front of us, to equalize the effect."

At the distance of about five leagues from Besançon, in France, there is another example of a grotto, containing ice in summer, a foot and-a-half thick on the floor, and festoons of icicles around the opening inside, which melt away as the winter approaches. This singular phenomenon here noticed, is susceptible of a very satisfactory explanation. It depends on the relation which subsists between the moisture in these caverns and the external air. In summer, when it is hot and dry outside, evaporation takes place. By this means, a considerable degree of warmth is withdrawn from the inclosed air, the vapours making their escape through the openings, and through fissures in the roofs. As the exterior temperature increases, the more rigorously the evaporation is carried on, producing a degree of cold in the interior, which may sink beneath

D