THE COASTS OF SICILV. 129 



sea sometimes vanish as rapidly as they have ap- 

 peared, as those islands of the seas of Iceland and the 

 Azores which rise from the waves, eject flames and 

 then sink into the abysses, from whence they had 

 emerged ; as, for instance, the Isle of Julia, which 

 in 1831 rose in the Sicilian waters, although not 

 a trace of it now remains ; at other times, these 

 islands become solidified and increase in number, as, 

 for instance, in the case of Santorin, the Aleutian 

 Islands, and the Azores, where in 1757 nine new 

 islands were formed in less than a twelvemonth. At 

 one place we find that in a single night plains have 

 been upheaved, bristling with volcanic cones, as was 

 the case atMechoacham at the time of the formation of 

 the volcano of Jorullo in 1759; while, in another place, 

 we find that they are buried in the entrails of the 

 globe, as, for instance, at Sorca, where forty villages 

 disappeared with the land on which they stood. 

 Mountains crumble away and are replaced by lakes, 

 whilst others, on the contrary, rise from the earth, 

 block up the course of rivers, or replace a bay by a 

 cape. Earthquakes cause our fields to undulate, 

 like an agitated sea overthrowing and engulfing 

 our cities, and even at times shaking both hemi- 

 spheres at once. We see therefore that everything 

 teaches us that the crust which we crJl terra Jirma, 

 in reality very little merits that title. We see how 

 thin and fragile is that pellicle which envelopes the 

 fluid part of our globe*, and we learn to understand 



* A very erroneous idea is generally entertained in reference to 

 VOL. II. K 



