tlarthquakes in Sicily. 229 



these products may not be extremely deep, and that yet 

 they may reach the surface ? Who knows but in other 

 places, those grand laboratories of nature, from causes which 

 will always elude our investigation, may be so deeply seated, 

 that their productions never arrive at the surface, and that 

 no other evidences of their existence, no other effects of 

 their action are perceptible, but the shaking of the earth, 

 and the rumblings which the aeriform elastic vapours make 

 in the cavities of the earth.* 



Three principal furnaces have their outlets on the three 

 sides of Sicily, and each with a force proportioned to the 

 circumstances v/hich supply it with combustible matter, 

 -^tna on the eastern side, by the immensity of its power, 

 rules the whole island. When in full action the island 

 trembles to its foundation, and feiils the mighty power which 

 has borne rule there from time immemorial. Its roarings 

 are heard from one extremity to the other; but the parts 

 most agitated are those in its neighbourhood, and those be- 

 tween it and Cape Passora, a space of about a hundred 

 miles. 



The mountain of Sciacca, on the southern shore towards 

 the west, seems to cover a place where the elements have 

 been in ceaseless operation for ages. From dark caverns, 

 which open in the more elevated parts, torrents of water, in 

 the form of heated vapour, with sulphurous gases, are 

 ejected. Having penetrated into the internal recesses, but 

 unable to extinguish the fermentation, the water becomes 

 invested with fire, is converted into vapour, and thus exhaled 

 into our atmosphere. The extrication of the steam causes 

 in the internal caverns, a deep roaring, and often fearful con- 

 vulsions, felt at a great distance. At such times, Sciacca, at 

 the foot of the mountain, experiences the most violent com- 

 motions. In 1578 it was reduced to ruins. In J 652, for fif- 



* The deficiency of volcanoes in any place, oug-ht not to be made an 

 argument against the existence of igneous fermentation under that 

 place, since it may be plead at a great depth, or at least not sufficiently 

 large to form an eruption. And indeed, notwithstanding the numerous 

 volcanoes which have burnt at one time or other, in almost every region, 

 may it not be possible that there is still but one great reservoir of fire, 

 the remains of that which in remote ages has burst out in Portugal, 

 Spain, the South of France, Italy, the Islands of Great Britain, Germany, 

 Bohemia, about the Bosphoms, on the coasts of Asia, and in many other 

 places. 



