VOLCANOES 241 



nietory of all islands of elevation. For upwards of 2000 

 years, as far as history and tradition certify, it would appear 

 as if nature were striving to form a volcano in the midst of 

 the crater of elevation.''* Similar insular elevations, and 

 almost always at regular intervals of 80 or 90 years,f have 

 been manifested in the Island of St. Michael, in the Azores ; 

 hut in this case the bottom of the sea has not been elevated 

 at exactly the same parts. J The island which Captain Tillard 

 named Sabrhm, appeared unfortunately at a time (the 30th of 

 January, 1811), when the political relations of the maritime 

 nations of Western Europe prevented that attention being 

 bestowed upon the subject by scientific institutions, which 

 was afterwards directed to the sudden appearance (the 2nd 

 July, 1831), and the speedy destruction of the igneous island 

 of Ferdinandea in the Sicilian sea, between the limestone 



* Leop. von Buch, Physik. Beschr. der Canar. Inseln, s. 356-358, 

 and particularly the French translation of this excellent work, p. 402 ; 

 and his memoir in Poggendorff's Annalen, bd. xxxviii. s. 183. A sub- 

 marine island has quite recently made its appearance, within the crater 

 of Santorino. In 1810 it was still fifteen fathoms below the surface of 

 the sea, but in 1830 it had risen to within three or four. It rises 

 steeply, like a great cone, from the bottom of the sea, and the con- 

 tinuous activity of the submarine crater is obvious from the circum- 

 stance that sulphurous acid vapours are mixed with the sea water, in 

 the eastern bay of Neokammeni, in the same manner as at Yromolimni, 

 near Methana. Coppered ships lie at anchor in the bay, in order to 

 get their bottoms cleaned and polished by this natural (volcanic) 

 process. (Yirlet, in the Bulletin de la Societe Geologique de France, 

 t. iii. p. 109, and Fiedler, Seise durch Griechenland, th. ii. s. 469 

 and 584.) 



t Appearance of a new island near St. Miguel, one of the Azores, 

 llth June, 1638, 31st December, 1719, 13th June, 1811. 



J [My esteemed friend, Dr. Webster, Professor of Chemistry and 

 Mineralogy :>t Harvard College, Cambridge, Massachusetts, U. S., in 

 his Description of the Island of St. Michael, <kc., Boston, 1822, gives 

 an interesting account of the sudden appearance of the island named 

 Sabrina, which was about a mile in circumference, and two or three 

 hundred feet above the level of the ocean. After continuing for some 

 weeks, it sank into the sea. Dr. Webster describes the whole of 

 the Island of St. Michael as volcanic, and containing a number of 

 conical hills of trachyte, several of which have craters, and appear at 

 some former time to have been the openings of volcanoes. The hot 

 springs which abound in the island are impregnated with sulphuretted 

 aydrogen and carbonic acid gases, appearing to ittest ihe existence {/ 

 roicanic action.} TV. 



