CAVERXS. 



239 



contribute to invest the cavities of the earth with exciting interest ; nor is it strange to 

 find them interwoven with the traditions and mythologies of unenlightened nations. On 

 account of their sombre interior and strange outline being adapted to impose upon an 

 ignorant populace, and give effect to religious observances, the priesthoods of antiquity 

 localised in caverns their false divinities, and celebrated sanguinary rites upon the 

 natural altars found in their recesses. A cave, with a priestess seated upon a tripod at 

 its mouth, pretending to inhale a vapour from the interior which inspired a knowledge 

 of future events, the gift of Apollo, was the original Delphian oracle, reverenced by the 

 mind of Greece, and resorted to by the proudest monarchs of the ancient world. The 

 cavern, along with the deep forest, commended itself to the primitive inhabitants of 

 northern Europe by its mystery and gloom as an appropriate spot for the performance of 

 a barbarous worship, and many local titles of such sites preserve the memory of their 

 former uses. An instance of this we have in Thor's cave, or, as Darwin calls it, 



" The blood-smear'd mansion of gigantic Thor," 



a broad excavation on the face of a huge rock in the limestone district of Derbyshire, 

 divided into two chambers, one beyond the other, with a detached stone at the further 

 extremity, where the light of day is very much subdued. But in India the largest use 

 has been made of caverns for religious purposes, and immense pains have been taken 

 with their adornment, extension, and architecture, at Elephanta, Salsette, and Ellora, 

 where there are elaborately Avrought temples constructed, probably out of small natural 

 crevices in the rock. We shall now refer to a few of those cavities which are entirely 

 the workmanship of nature, with whose form man has not intermeddled, and notice the 

 principal phenomena which they exhibit. 



That extensive cavities exist in the interior of the crust of the globe is evident from 

 the phenomena of volcanoes and earthquakes. They are not accessible to observation, 

 but the repeated tremblings of the soil in various places, and experiments made of 

 oscillations of the pendulum, point to the conclusion, that there are large underlying 

 hollows, at no great distance from the surface, of which the superficial land forms the 

 ^ , roof. The table-land of Quito, sur 



rounded by the most powerful volcanoes 

 upon the earth, and the remarkable 

 plain of Jorullo, are supposed to be ex 

 amples of this. Condamine believed 

 that a considerable portion of the 

 former district was to be regarded as 

 the dome of an enormous vault ; and 

 Parrot has shown it to be highly pro 

 bable, by a careful calculation, that a 

 cavity of at least a cubic mile and a 

 half exists beneath its surface. The 

 rumbling noise, like that of distant 

 thunder, which on the testimony of 

 Humboldt usually precedes and accom 

 panies 'the eruption of its volcanoes, 

 affords evidence in favour of this sup 

 position, and as an increase of the subterranean vacuity must be the necessary conse 

 quence of every outbreak, it is not at all an improbable event, that the blooming landscape 

 will ultimately fall in, and this piece of table-land become an immense depression. 

 The quantity of material scooped out of the interior of the earth by volcanic action is 



Jorullo, Mexico. 



