Uxviii NOTES. 



small variations of atmospheric pressure which accompany different winds, are far 

 from enabling us to assign, as yet, any satisfactory explanation. Bembo, who 

 was educated in Sicily by Greek refugees, has given us a pleasing relation of his 

 youthful wanderings in his jEtna Dialogus, written in the middle of the sixteenth 

 century, in which he propounds the theory of the introduction of sea water to 

 the focus of volcanic activity, and of the necessity of the proximity of the sea 

 to the existence of active volcanoes. During the ascent of ^Etna, the following 

 questions were proposed : " Explana potius nobis qua? petimus, ea incendia 

 unde oriantur et orta quomodo perdurent ? In omni tellure nuspiam majores 

 fistulse aut meatus ampliores sunt quam in locis, qua? vel mari vicina sunt, Vel 

 a mari protinus alluuntur : mare erodit ilia facillime pergitque in viscera terras. 

 Itaque cum in aliena regna sibi viam faciat, veutis etiam facit ; ex quo fit, ut 

 loca quseque maritima maxime terrse motibus subjecta sint, parum mediter- 

 rauea. Habes quum in sulfuris venas venti furentes inciderint, unde inceudia 

 oriantur JEtnsR tuse. Vides, quse mare in radicibus habeat, qua? sulfurea sit, 

 quae cavernosa, qua? a mari aliquando perforata ventos admiserit astuantes, 

 per quos idonea flammse materies incenderetur. 



C 235 ) p. 232. Compare Gay-Lussac, " sur les Volcans," in the Annales de 

 Chimie, T. xxii. p. 427 ; and Bischof, Warmelehre, S. 272. The eruptions 

 of smoke and of aqueous vapour which have been seen at different times round 

 Lancerote, Iceland, and the Kurile islands during eruptions of the neighbouring 

 volcanoes, show a reaction of the volcanic foci, in which the hydrostatic 

 pressure of the waters of the adjacent sea is overcome by the greater expansive 

 force of the vapours or gases. 



C 236 ) p. 232. Abel-Re'musat, Lettre a M. Cordier, in the Aimales de 

 Mines, T. v. p. 137. 



P) p. 232. Humboldt, Asie centrale, T. ii. pp. 3033, 3852, 7080, 

 and 426 428. The existence of active volcanoes in Kordofan, 540 miles 

 from the Red Sea, has been recently contradicted by Riippell (Reisen in 

 Nubien, 1829, S. 151). 



C 238 ) p. 234. Dufrenoy et Elie de Beaumont, Explication de la Carte 

 geologique de la France, T. i. p. 89. 



C 239 ) p. 234. Sophocl. Philoct. v. 971 and 972. On the supposed epoch 

 of the extinction of the "Lemnian fire" in the time of Alexander, compare 

 Buttmann, in Museum der Alterthumswissenschaft, Bd. i. 1807, S. 295 ; 

 Dureau de la Malle, in Malte-Brun, Annales des Voyages, T. ix. 1809, p. 5 ; 

 Ukert, in Bertuch, Geogr. Ephemeriden, Bd. xxxix. 1812, S. 361 ; Rhode, 

 Res Lemnicsc, 1829, p. 8; and Walter iiber Abnahme der vulkauischen 

 Thatigkeit in historischen Zeiten, 1844, S. 24. Choiseul's Chart of Lemnos 



