THIi EAIITH. 67 



from the lowest abysues of the earth.' A volcano may be 

 considered as a cannon of immense size, the mouth of which is 

 often near two miles in circimiference. From this dreadful 

 aperture are discharged torrents of flame and sulphur, and rivers 

 of melted metal. Whole clouds of smoke and ashes, with rocks 

 of enormous size, are discharged to many miles' distance ; so 

 that the force of the most powerful artillery, is but as a breeze 

 agitating a feather in comparison. In the deluge of fire 

 and melted matter which runs down the sides of the moun- 

 tain, whole cities are sometimes swallowed u]) and consumed. 

 Those rivers of liquid fire are sometimes two hundred feet deep ; 

 and when they harden, frequently form considerable hills. Nor 

 is the danger of these confined to the eruption only : but tluj 

 force of the internal fire struggling for vent, frequently produces 

 earthquakes through the whole region where the volcano is situ- 

 ated. So dreadful have been these appearances, that men's terrors 

 have added new horrors to the scene, and they have regarded as 

 prodigies, what we know to be the result of natural causes. 

 Some philosophers have considered them as vents communicat- 

 ing with the fires of the centre ; and the ignorant as the mouths 

 of hell itself. Astonishment produces fear, and fear supersti- 

 tion : the inhabitants of Iceland believe the bellowings of Hecla 

 are nothing else but the cries of the damned, and that its erup- 

 tions are contrived to increase their tortures. 



But if we regard this astonishing scene of terror with a more 

 tranquil and inquisitive eye, we shall find that these con- 

 flagrations are produced by very obvious and naturnl causes. 

 We have already been apprised of the various mineral substances 

 in the bosom of the earth, and their aptness to burst out into 

 flames. Marcasites and pyrites, in particular, by being humi 

 fied with water or air, contract this heat, and often endeavour tu 

 expand with irresistible explosion. These, therefore, being 

 lodged in the depths of the earth, or in the bosom of mountains, 

 and being either washed by the accidental influx of waters be- 

 low, or fanned by air, insinuating itself through perpendiculai 

 fissures from above, take fire at first by only heaving in eaith- 

 quakes, but at length by bm-stiiig through every obstacle, and 

 making their dreadful discharge in a volcano. 



I Bufllin, vol. I p. 29U 



