328 cosmos. 



that the thickness of the crust already solidified is the same 

 in all regions, the more important is the consideration of the 

 number and geographical position of the volcanoes which 

 have been open in historical periods. Such an examination 

 of the geography of volcanoes can only be perfected by fre- 

 quently-renewed attempts. 



I. Europe. 



JEtn a, 



Volcano in the Lijparis, 



Stromboli, 



Ischia, 



Vesuvius, 



Santorin, 



LemnoSj 



All belong to the great basin of the Mediterranean, but to 

 its European and not to its African shores ; and all these 

 seven volcanoes are still, or have been, active in known his- 

 torical periods ; the burning mountain Mosychlos in Lemnos, 

 wnjch Homer names the favorite seat of Hephrestos, was 

 only destroyed and sunk beneath the waves of the sea by 

 earthquakes, together with the island of Chryse, after the 

 time of the great Macedonian {Cosmos, vol. i., p. 24G ; Ukert, 

 Geogr. der Griechen unci Romer, th. ii., abth. 1, s. 198). The 

 great upheaval of the three Kaimenes in the middle of the 

 Gulf of Santorin (partly inclosed by Thera, Therasia, and 

 Aspronisi), which has been repeated several times within 

 about 1900 years (from 186 B.C. to 1712 of our epoch), had 

 in their production and disappearance a remarkable similar- 

 ity with the relatively unimportant phenomenon of the tem- 

 porary formation of the islands which were called Graham, 

 Julia, and Ferdinandea, between Sciacca and Pantellaria. 

 Upon the peninsula of Methana, which has already been fre- 

 quently mentioned (Cosmos, vol. i., p. 240; vol. v., p. 218), 

 there are distinct traces of volcanic eruptions in the reddish* 

 brown trachyte which rises from the limestone near Kaime^ 

 nochari and Kaimeno (Curtius, Pelop., bd. ii., s. 439). 



Of pre-historic volcanoes with fresh traces of the emission 

 of lava from craters there are, counting from north to south, 

 those of the Eifel (ALosenberg, Geroldstein), farthest to the 

 north ; the great crater of elevation in which Schemnitz is 

 situated; Auvergr.c (Chaine des Puys or of the Monts Domes 



