VOLCANO. 



hiftorians of that period. Flames «?«re alfo obferved to 

 burft from the neighbouring mountains during the earth- 

 quake at Lifbon in 1755. Though thefe phenomena may 

 proceed from fubterranean fire as the primary caufe, yet 

 they differ from volcanic fires, as the latter throw out 

 their contents in an ignited ftate ; but the flames which ac- 

 company earthquakes, appear to arife from the ignition of 

 vapour at the furface. 



Burning and Exl'mSl Volcanoes. — When we take a general 

 view of the terreftrial globe, we obferve volcanoes in every 

 parallel of latitude, from Iceland and Kamtfchatka, in the 

 north, to Terra del Fuego in the fouth. They are more 

 abundantly fcattered over the ocean than the continent, and 

 are more numerous in America than in the old world. They 

 are found at every degree of elevation, from the depths of 

 tlie fea to the fummits of the Andes. Ancient volcanic 

 craters, which have been for ages extinft or dormant, have 

 left undoubted velliges of their prior ftate of aftivity in 

 various countries where no volcanoes at prefent exift ; and 

 volcanic rocks are found even where all veftiges of volcanic 

 craters have been long obliterated. 



Our knowledge of volcanic geography is at prefent im- 

 perfeA, as a large portion of the earth's furface has not yet 

 been examined ; and our knowledge of volcanic iflands in 

 the Indian and Pacific oceans is confined to thofe which 

 were in a Hate of aftive eruption at the time they were 

 pafled by navigators. Of the fubmarine volcanoes fcattered 

 over the bed of the ocean we have no account, and it is only 

 when they occur in the vicinity of civihzed countries, that 

 vre can afcertain their locahty. At the beginning of the 

 prefent century, the aftivc volcanoes then known were 

 Hated at about two hundred. Travellers and navigators 

 have fince enlarged the number. Perhaps it would not be 

 exceeding the faft, were we to eftimate the number of aftive 

 volcanoes in the world at one thoufand, including all thofe 

 virhich ftill preferve a confiderable degree of heat, and prefent 

 other indications that they are not extinguifhed, but dormant. 



The only aftive volcano on the continent of Europe is 

 Vefuvius. The Solfatara and .Monte Nuovo in the vicinity 

 may be regarded as dormant. Hillory mentions a volcano 

 in Albania, which deilroyed Durazzo in 1269. 



Of the European iflands, Iceland is the moft extenfively 

 volcanic, the whole foil of that country is apparently the 

 produft of fire. It contains fix large aftive volcanoes, be- 

 fides numerous fmaller ones, and boiling fprings. 



Sicily contains Etna and the various volcanic mountains 

 on its fides, with the mud volcano of Maccaluba. 



Three of the Lipari iflands are at prefent aftive : Strom- 

 boli, Vulcano, and Vulcanello. 



Santorini and the neighbouring ifles are evidently placed 

 near or over a great fubmarine volcano, by which they have 

 at different times been formed. 



The ifland of Milo, about twenty leagues to the eaft of 

 Santorini, has a volcano in an aftive Hate ; the whole of the 

 ifland is alfo ilated to be volcanic. 



The extinft or dormant volcanoes in Europe are far more 

 numerous than thofe which are at prefent aftive. In Cam- 

 pania alone, between Naples and Cumea, in the fpace of 

 twenty miles in length and ten in breadth, according to 

 Breiflak, there are no lefs than fixty craters, without rec- 

 koning thofe in the neighbouring iflands, which are nu- 

 merous. Some of the craters are larger than that of Vefu- 

 vius. The crater of Quarto even greatly exceeds that of 

 Etna ; its diameter is nearly two miles. The crater on 

 which the ancient city of Cumea is fituated, has thrown out 

 a torrent of lava nine hundred feet broad, and from twenty- 

 five to thirty feel in depth. 



This crater belongs to a volcano extinft from the moft 

 remote ages. The foundation of Cumea was about twelve 

 hundred years prior to the Chriftian era, hence Breiflak 

 adds, the laft eruptions muft have taken place more than 

 three thoufand years fince, as the Greeks would not have 

 founded their city on the mouth of an aftive volcano. 



The other parts of Italy, from the Veronefe and the Vi- 

 centin territory, with that of Padua, to the extremity of 

 Calabria, are covered with the inconteftible veftiges of 

 ancient volcanoes. 



Sicily prefents a great number of extinft volcanoes, with- 

 out reckoning thofe on the fides of Etna, of which fome 

 are equal to Vefuvius. Many of the Mediterranean iflands, 

 at prefent in a ftate of repofe, have formerly been volcanic, 

 as the iflands of Elba, Sardinia, Ifchia, Procita, the whole 

 of the Lipari iflands, with the greater part of tlie iflands in 

 the Grecian Archipelago. Lemnos was formerly regarded 

 as the arfenal of Vulcan. 



In Spain and Portugal there are volcanic craters ftill to 

 be traced. The Souffriere of Conilla, near Cadiz, is an 

 ancient volcano. The environs of Burgos are entirely com- 

 pofed of lava, pumice, and other volcanic produfts. The 

 famous falt-minc of Pofa, near Burgos, is ftated to be 

 fituated in the midft of an immenfe crater. 



In France there are numerous extinft volcanoes, as thofe 

 of the Vivarais and Velay, defcribed by Faujas St. Fond ; 

 and thofe of Auvergne, defcribed by DaubuifTon. The ex- 

 tinft volcanoes in Languedoc and Provence are faid to be 

 very numerous. The alps of Dauphiny, according to La- 

 manon, contain a crater of large extent. 



There are entire chains of volcanic mountains on the 

 banks of the Rhine, in the Brifgau, and the environs of 

 Andernach. 



The northern countries of Europe poffefs fewer indu- 

 bitable veftiges of volcanic craters, though volcanic pro- 

 dufts and rocks, nearly aUied to lavas, exift in various parts 

 of Germany and Hungary, and are fuppofed by many geo- 

 logifts to be formed by fubterranean fire, at a very remote 

 period. 



According to the Italian geologift BreifljJt, the famous 

 gold and tellurium mine of Nagyag is fituated in the crater 

 of an extinft volcano. See Tellurium Mines. 



In Great Britain, on the weftern fide, particularly in the 

 mountains of North Wales and Cumberland, are various 

 circular cavities, partly filled with water, which bear a near 

 refemblance to extinft craters. The rocks by which they 

 are furrounded are generally a porphyritic trap, a rock 

 wliich is fuppofed by many geologifts to have had an igneous 

 origin. See Trap, and RowLEY-i?aj-. 



Above the village of Buttermere, in Cumberland, be- 

 tween the fummits of the mountains called Redpike and 

 Highftile, there is a large elevated crater of this kind, con- 

 taining in its centre a fmall tarn or lake. The rocks which 

 furround it confift of clink-ftone-porphyry which melts 

 with great facility, and porphyritic red felfpar, and are in 

 fome parts rudely columnar. The fide neareft the lake is 

 broken down. We have no doubt, from an examination of 

 the place, that it would be defcribed by many geologifts 

 on the continent, as the well-defined crater of an extinft 

 volcano. Von Buch, whofe acquaintance with volcanoes is 

 extenfive, after a recent tour through this part of England, 

 informed us that many of the mountains in Cumberland re- 

 femble thofe in Auvergne, and other parts of the world, 

 which are fuppofed to have been foftened and elevated by 

 fubterranean heat, without ever having flowed as lavas. 



The bafaltic hills of many parts of Scotland have been 

 defcribed by Faujas St. Fond as volcanic, and the bafaltic 



mountains 



