TRUE VOLCANOES. 349 



The more improbable it is that the thickness of the crust 

 already solidified is the same in all regions, the more impor- 

 tant is the consideration of the number and geographical 

 position of the volcanoes which have been open in his- 

 torical periods. Such an examination of the geography of 

 volcanoes can only be perfected by frequently renewed 

 attempts. 



I. EUROPE. 



Etna, 



Volcano in the Liparis, 



Sfromboh, 



Iscliia, 



Vesuvius, 



Santorin, 



Lemnos, 



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 histo- 

 rical periods ; the burning mountain Mosychlos in Leninos, 

 which Homer names the favourite seat of Hephaestos was 

 only destroyed and sunk beneath the w r aves of the sea by 

 earthquakes, together with the island of Chryse, after the time 

 of the great Macedonian (Cosmos, vol. i, p. 246; Ukert, Geogr. 

 der Griechen und Rdmer, 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 similarity 

 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 

 frequently mentioned (Cosmos, vol. i, p. 239 ; vol. v, p. 229), 

 there are distinct traces of volcanic eruptions in the reddish 

 brown trachyte which rises from the limestone near Kai 

 menochari and Kaimeno (Curtius, Pelop. Bd.ii. s. 439). 

 Of prehistoric Volcanoes with frcFh traces of the emissioD 



