On Volcanoes^, ' 219 



ON VOLCANOES. 



Caloric, another cause of combustion, whether it be a sub- 

 stance too fine for being found alone, or a mere phenomenon of 

 other bodies, is the grand agent which counteracts the law of 

 gravitation, and enables the motions and functions of life to be 

 carried on. Whatever is melted is melted by fire ; and whatever 

 is kept in that state, is so kept by the same. Caloric and ice 

 form water; the component parts of water, with more caloric, be- 

 comes oxygen and hydrogen gases; and if these be brought to- 

 gether in the proper proportions and a body applied that can cause 

 them to part with their caloric, water is the result; and by the 

 further abstraction of caloric, that water may be changed to ice. 

 There are powers in natural substances, by which caloric may be 

 made sensible without human aid, and the most remarkable of these 

 are volcanoes. The consideration of those phenomena of nature 

 called volcanoes, of which we have instances in the mountains 

 ^tna and Vesuvius, is very interesting. From these, at different 

 intervals, issue terrible eruptions of fiery matter. Sometimes only 

 a black vapor is seen to arise, and at the same time are heard 

 hollow rumbhng noises, often succeeded by strong flashes of fire, 

 and peals like thunder, accompanied with the sensation of an earth- 

 quake. The vapor then becomes luminous, and showers of 

 stones and lava are evolved, part of which fall again within the 

 crater, though enough fall without to lay waste the neighboring 

 country, and are sometimes whirled to a considerable distance. 

 These terrible explosions are sometimes even more violent. 

 With the noise of thunder, torrents of burning sulphur, and liquid 

 metals, enveloped with clouds of ashes and smoke, are hurled to 

 an immense distance. Rocks upborne by the force of the explo- 

 sion, fall with a dreadful crash; and cataracts of fire pour down 

 the steep of the mdiintain; the deluge pours over villages, planta- 

 tions, and cities; the earth rocks, and they who escape the flood, 

 fall within the gulf made by the earthquake, or, tossed from wave 

 to wave, are buried in the general wreck. 



A volcano, or burning mountain, is a wonderful phenomenon. 

 The crater, that is, orifice or mouth of a volcano, in some cases, 

 is more than a mile across; and from this mouth are emitted tor- 

 rents of smoke and flame; rivers of bitumen, sulphur, and melted 

 metal, the mixture bearing the name of lava; it ejects clouds of 

 cinders and stones, and sometimes enormous rocks, to many 

 leagues distant, when merely to stir them would baffle the utmost 

 efforts of human strength. The combustion is so terrible, and 



